Merge "Upgrade curl to curl-7_70_0" am: 47cd0cac1b am: ea155d05e7

Change-Id: I487c81955205e3bb979e2f0d41b53c68ab72dd17

74 files changed, 2719 insertions, 1348 deletions

diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index e73efb90..1d71e149 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -1,3 +1,24 @@
+#***************************************************************************
+#                                  _   _ ____  _
+#  Project                     ___| | | |  _ \| |
+#                             / __| | | | |_) | |
+#                            | (__| |_| |  _ <| |___
+#                             \___|\___/|_| \_\_____|
+#
+# Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
+#
+# This software is licensed as described in the file COPYING, which
+# you should have received as part of this distribution. The terms
+# are also available at https://curl.haxx.se/docs/copyright.html.
+#
+# You may opt to use, copy, modify, merge, publish, distribute and/or sell
+# copies of the Software, and permit persons to whom the Software is
+# furnished to do so, under the terms of the COPYING file.
+#
+# This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+# KIND, either express or implied.
+#
+###########################################################################
 set(LIB_NAME libcurl)
 
 if(BUILD_SHARED_LIBS)
@@ -71,6 +92,11 @@ add_library(
   ${HHEADERS} ${CSOURCES}
   )
 
+add_library(
+  ${PROJECT_NAME}::${LIB_NAME}
+  ALIAS ${LIB_NAME}
+  )
+
 if(MSVC AND NOT BUILD_SHARED_LIBS)
   set_target_properties(${LIB_NAME} PROPERTIES STATIC_LIBRARY_FLAGS ${CMAKE_EXE_LINKER_FLAGS})
 endif()
@@ -122,5 +148,5 @@ install(TARGETS ${LIB_NAME}
 
 export(TARGETS ${LIB_NAME}
        APPEND FILE ${PROJECT_BINARY_DIR}/libcurl-target.cmake
-       NAMESPACE CURL::
+       NAMESPACE ${PROJECT_NAME}::
 )
diff --git a/lib/Makefile.Watcom b/lib/Makefile.Watcom
index 942cd0c7..6ea975b5 100644
--- a/lib/Makefile.Watcom
+++ b/lib/Makefile.Watcom
@@ -6,7 +6,7 @@
 #                             \___|\___/|_| \_\_____|
 #
 # Copyright (C) 2005 - 2009, Gisle Vanem <gvanem@yahoo.no>.
-# Copyright (C) 2005 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
+# Copyright (C) 2005 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
 #
 # This software is licensed as described in the file COPYING, which
 # you should have received as part of this distribution. The terms
diff --git a/lib/Makefile.am b/lib/Makefile.am
index 516a2394..f2886ec6 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -5,7 +5,7 @@
 #                            | (__| |_| |  _ <| |___
 #                             \___|\___/|_| \_\_____|
 #
-# Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+# Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
 #
 # This software is licensed as described in the file COPYING, which
 # you should have received as part of this distribution. The terms
@@ -29,7 +29,8 @@ EXTRA_DIST = Makefile.m32 config-win32.h config-win32ce.h           \
  makefile.amiga Makefile.netware nwlib.c nwos.c config-win32ce.h    \
  config-os400.h setup-os400.h config-symbian.h Makefile.Watcom      \
  config-tpf.h mk-ca-bundle.pl mk-ca-bundle.vbs $(CMAKE_DIST)        \
- firefox-db2pem.sh config-vxworks.h Makefile.vxworks checksrc.pl
+ firefox-db2pem.sh config-vxworks.h Makefile.vxworks checksrc.pl    \
+ setup-win32.h
 
 lib_LTLIBRARIES = libcurl.la
 
diff --git a/lib/Makefile.inc b/lib/Makefile.inc
index 46ded90b..e3cf4189 100644
--- a/lib/Makefile.inc
+++ b/lib/Makefile.inc
@@ -20,71 +20,66 @@
 #
 ###########################################################################
 
-LIB_VAUTH_CFILES = vauth/vauth.c vauth/cleartext.c vauth/cram.c         \
-  vauth/digest.c vauth/digest_sspi.c vauth/krb5_gssapi.c                \
-  vauth/krb5_sspi.c vauth/ntlm.c vauth/ntlm_sspi.c vauth/oauth2.c       \
-  vauth/spnego_gssapi.c vauth/spnego_sspi.c
+LIB_VAUTH_CFILES = vauth/cleartext.c vauth/cram.c vauth/digest.c             \
+  vauth/digest_sspi.c vauth/krb5_gssapi.c vauth/krb5_sspi.c vauth/ntlm.c     \
+  vauth/ntlm_sspi.c vauth/oauth2.c vauth/spnego_gssapi.c vauth/spnego_sspi.c \
+  vauth/vauth.c
 
-LIB_VAUTH_HFILES = vauth/vauth.h vauth/digest.h vauth/ntlm.h
+LIB_VAUTH_HFILES = vauth/digest.h vauth/ntlm.h vauth/vauth.h
 
-LIB_VTLS_CFILES = vtls/openssl.c vtls/gtls.c vtls/vtls.c vtls/nss.c     \
-  vtls/mbedtls_threadlock.c vtls/wolfssl.c vtls/schannel.c              \
-  vtls/schannel_verify.c vtls/sectransp.c vtls/gskit.c vtls/mbedtls.c   \
-  vtls/mesalink.c vtls/bearssl.c
+LIB_VTLS_CFILES = vtls/bearssl.c vtls/gskit.c vtls/gtls.c vtls/mbedtls.c \
+  vtls/mbedtls_threadlock.c vtls/mesalink.c vtls/nss.c vtls/openssl.c    \
+  vtls/schannel.c vtls/schannel_verify.c vtls/sectransp.c vtls/vtls.c    \
+  vtls/wolfssl.c
 
-LIB_VTLS_HFILES = vtls/openssl.h vtls/vtls.h vtls/gtls.h vtls/nssg.h    \
-  vtls/mbedtls_threadlock.h vtls/wolfssl.h vtls/schannel.h              \
-  vtls/sectransp.h vtls/gskit.h vtls/mbedtls.h vtls/mesalink.h          \
-  vtls/bearssl.h
+LIB_VTLS_HFILES = vtls/bearssl.h vtls/gskit.h vtls/gtls.h vtls/mbedtls.h \
+  vtls/mbedtls_threadlock.h vtls/mesalink.h vtls/nssg.h vtls/openssl.h   \
+  vtls/schannel.h vtls/sectransp.h vtls/vtls.h vtls/wolfssl.h
 
 LIB_VQUIC_CFILES = vquic/ngtcp2.c vquic/quiche.c
 
 LIB_VQUIC_HFILES = vquic/ngtcp2.h vquic/quiche.h
 
-LIB_VSSH_CFILES = vssh/libssh2.c vssh/libssh.c vssh/wolfssh.c
+LIB_VSSH_CFILES = vssh/libssh.c vssh/libssh2.c vssh/wolfssh.c
 
 LIB_VSSH_HFILES = vssh/ssh.h
 
-LIB_CFILES = file.c timeval.c base64.c hostip.c progress.c formdata.c   \
-  cookie.c http.c sendf.c ftp.c url.c dict.c if2ip.c speedcheck.c       \
-  ldap.c version.c getenv.c escape.c mprintf.c telnet.c netrc.c         \
-  getinfo.c transfer.c strcase.c easy.c security.c curl_fnmatch.c       \
-  fileinfo.c ftplistparser.c wildcard.c krb5.c memdebug.c http_chunks.c \
-  strtok.c connect.c llist.c hash.c multi.c content_encoding.c share.c  \
-  http_digest.c md4.c md5.c http_negotiate.c inet_pton.c strtoofft.c    \
-  strerror.c amigaos.c hostasyn.c hostip4.c hostip6.c hostsyn.c         \
-  inet_ntop.c parsedate.c select.c tftp.c splay.c strdup.c socks.c      \
-  curl_addrinfo.c socks_gssapi.c socks_sspi.c                           \
-  curl_sspi.c slist.c nonblock.c curl_memrchr.c imap.c pop3.c smtp.c    \
-  pingpong.c rtsp.c curl_threads.c warnless.c hmac.c curl_rtmp.c        \
-  openldap.c curl_gethostname.c gopher.c idn_win32.c                    \
-  http_proxy.c non-ascii.c asyn-ares.c asyn-thread.c curl_gssapi.c      \
-  http_ntlm.c curl_ntlm_wb.c curl_ntlm_core.c curl_sasl.c rand.c        \
-  curl_multibyte.c hostcheck.c conncache.c dotdot.c                     \
-  x509asn1.c http2.c smb.c curl_endian.c curl_des.c system_win32.c      \
-  mime.c sha256.c setopt.c curl_path.c curl_ctype.c curl_range.c psl.c  \
-  doh.c urlapi.c curl_get_line.c altsvc.c socketpair.c rename.c
+LIB_CFILES = altsvc.c amigaos.c asyn-ares.c asyn-thread.c base64.c            \
+  conncache.c connect.c content_encoding.c cookie.c curl_addrinfo.c           \
+  curl_ctype.c curl_des.c curl_endian.c curl_fnmatch.c curl_get_line.c        \
+  curl_gethostname.c curl_gssapi.c curl_memrchr.c curl_multibyte.c            \
+  curl_ntlm_core.c curl_ntlm_wb.c curl_path.c curl_range.c curl_rtmp.c        \
+  curl_sasl.c curl_sspi.c curl_threads.c dict.c dotdot.c easy.c escape.c      \
+  file.c fileinfo.c formdata.c ftp.c url.c ftplistparser.c getenv.c getinfo.c \
+  gopher.c hash.c hmac.c hostasyn.c hostcheck.c hostip.c hostip4.c hostip6.c  \
+  hostsyn.c http.c http2.c http_chunks.c http_digest.c http_negotiate.c       \
+  http_ntlm.c http_proxy.c idn_win32.c if2ip.c imap.c inet_ntop.c inet_pton.c \
+  krb5.c ldap.c llist.c md4.c md5.c memdebug.c mime.c mprintf.c mqtt.c        \
+  multi.c netrc.c non-ascii.c nonblock.c openldap.c parsedate.c pingpong.c    \
+  pop3.c progress.c psl.c doh.c rand.c rename.c rtsp.c security.c select.c    \
+  sendf.c setopt.c sha256.c share.c slist.c smb.c smtp.c socketpair.c socks.c \
+  socks_gssapi.c socks_sspi.c speedcheck.c splay.c strcase.c strdup.c         \
+  strerror.c strtok.c strtoofft.c system_win32.c telnet.c tftp.c timeval.c    \
+  transfer.c urlapi.c version.c warnless.c wildcard.c x509asn1.c
 
-LIB_HFILES = arpa_telnet.h netrc.h file.h timeval.h hostip.h progress.h \
-  formdata.h cookie.h http.h sendf.h ftp.h url.h dict.h if2ip.h         \
-  speedcheck.h urldata.h curl_ldap.h escape.h telnet.h getinfo.h        \
-  strcase.h curl_sec.h memdebug.h http_chunks.h curl_fnmatch.h          \
-  wildcard.h fileinfo.h ftplistparser.h strtok.h connect.h llist.h      \
-  hash.h content_encoding.h share.h curl_md4.h curl_md5.h http_digest.h \
-  http_negotiate.h inet_pton.h amigaos.h strtoofft.h strerror.h         \
-  inet_ntop.h curlx.h curl_memory.h curl_setup.h transfer.h select.h    \
-  easyif.h multiif.h parsedate.h tftp.h sockaddr.h splay.h strdup.h     \
-  socks.h curl_base64.h curl_addrinfo.h curl_sspi.h                     \
-  slist.h nonblock.h curl_memrchr.h imap.h pop3.h smtp.h pingpong.h     \
-  rtsp.h curl_threads.h warnless.h curl_hmac.h curl_rtmp.h              \
-  curl_gethostname.h gopher.h http_proxy.h non-ascii.h asyn.h           \
-  http_ntlm.h curl_gssapi.h curl_ntlm_wb.h curl_ntlm_core.h             \
-  curl_sasl.h curl_multibyte.h hostcheck.h conncache.h                  \
-  curl_setup_once.h multihandle.h setup-vms.h dotdot.h                  \
-  x509asn1.h http2.h sigpipe.h smb.h curl_endian.h curl_des.h           \
-  curl_printf.h system_win32.h rand.h mime.h curl_sha256.h setopt.h     \
-  curl_path.h curl_ctype.h curl_range.h psl.h doh.h urlapi-int.h        \
-  curl_get_line.h altsvc.h quic.h socketpair.h rename.h
+LIB_HFILES = altsvc.h amigaos.h arpa_telnet.h asyn.h conncache.h connect.h    \
+  content_encoding.h cookie.h curl_addrinfo.h curl_base64.h curl_ctype.h      \
+  curl_des.h curl_endian.h curl_fnmatch.h curl_get_line.h curl_gethostname.h  \
+  curl_gssapi.h curl_hmac.h curl_ldap.h curl_md4.h curl_md5.h curl_memory.h   \
+  curl_memrchr.h curl_multibyte.h curl_ntlm_core.h curl_ntlm_wb.h curl_path.h \
+  curl_printf.h curl_range.h curl_rtmp.h curl_sasl.h curl_sec.h curl_setup.h  \
+  curl_setup_once.h curl_sha256.h curl_sspi.h curl_threads.h curlx.h dict.h   \
+  dotdot.h easyif.h escape.h file.h fileinfo.h formdata.h ftp.h url.h         \
+  ftplistparser.h getinfo.h gopher.h hash.h hostcheck.h hostip.h http.h       \
+  http2.h http_chunks.h http_digest.h http_negotiate.h http_ntlm.h            \
+  http_proxy.h if2ip.h imap.h inet_ntop.h inet_pton.h llist.h memdebug.h      \
+  mime.h mqtt.h multihandle.h multiif.h netrc.h non-ascii.h nonblock.h        \
+  parsedate.h pingpong.h pop3.h progress.h psl.h doh.h quic.h rand.h rename.h \
+  rtsp.h select.h sendf.h setopt.h setup-vms.h share.h sigpipe.h slist.h      \
+  smb.h smtp.h sockaddr.h socketpair.h socks.h speedcheck.h splay.h strcase.h \
+  strdup.h strerror.h strtok.h strtoofft.h system_win32.h telnet.h tftp.h     \
+  timeval.h transfer.h urlapi-int.h urldata.h warnless.h wildcard.h           \
+  x509asn1.h
 
 LIB_RCFILES = libcurl.rc
 
diff --git a/lib/Makefile.m32 b/lib/Makefile.m32
index ac6b3de6..fe8701bd 100644
--- a/lib/Makefile.m32
+++ b/lib/Makefile.m32
@@ -99,7 +99,7 @@ LDFLAGS = $(CURL_LDFLAG_EXTRAS) $(CURL_LDFLAG_EXTRAS_DLL) -s
 AR = $(CURL_AR)
 RANLIB = $(CURL_RANLIB)
 RC = $(CROSSPREFIX)windres
-RCFLAGS = --include-dir=$(PROOT)/include -DDEBUGBUILD=0 -O COFF
+RCFLAGS = --include-dir=$(PROOT)/include -DDEBUGBUILD=0 -O coff
 STRIP   = $(CROSSPREFIX)strip -g
 
 # Set environment var ARCH to your architecture to override autodetection.
diff --git a/lib/Makefile.netware b/lib/Makefile.netware
index 752d3d6f..2c16adba 100644
--- a/lib/Makefile.netware
+++ b/lib/Makefile.netware
@@ -669,8 +669,6 @@ endif
 	@echo $(DL)#endif$(DL) >> $@
 ifdef CABUNDLE
 	@echo $(DL)#define CURL_CA_BUNDLE "$(CABUNDLE)"$(DL) >> $@
-else
-	@echo $(DL)#define CURL_CA_BUNDLE getenv("CURL_CA_BUNDLE")$(DL) >> $@
 endif
 
 $(EXPORTF): $(CURL_INC)/curl/curl.h $(CURL_INC)/curl/easy.h $(CURL_INC)/curl/multi.h $(CURL_INC)/curl/mprintf.h
diff --git a/lib/Makefile.vxworks b/lib/Makefile.vxworks
index 7ff197f0..ada87fbd 100644
--- a/lib/Makefile.vxworks
+++ b/lib/Makefile.vxworks
@@ -1,3 +1,24 @@
+#***************************************************************************
+#                                  _   _ ____  _
+#  Project                     ___| | | |  _ \| |
+#                             / __| | | | |_) | |
+#                            | (__| |_| |  _ <| |___
+#                             \___|\___/|_| \_\_____|
+#
+# Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
+#
+# This software is licensed as described in the file COPYING, which
+# you should have received as part of this distribution. The terms
+# are also available at https://curl.haxx.se/docs/copyright.html.
+#
+# You may opt to use, copy, modify, merge, publish, distribute and/or sell
+# copies of the Software, and permit persons to whom the Software is
+# furnished to do so, under the terms of the COPYING file.
+#
+# This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+# KIND, either express or implied.
+#
+###########################################################################
 #*****************************************************************************
 #
 #
diff --git a/lib/checksrc.pl b/lib/checksrc.pl
index e1bb1a63..b074f274 100755
--- a/lib/checksrc.pl
+++ b/lib/checksrc.pl
@@ -6,7 +6,7 @@
 #                            | (__| |_| |  _ <| |___
 #                             \___|\___/|_| \_\_____|
 #
-# Copyright (C) 2011 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+# Copyright (C) 2011 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
 #
 # This software is licensed as described in the file COPYING, which
 # you should have received as part of this distribution. The terms
@@ -80,6 +80,7 @@ my %warnings = (
     'MULTISPACE'       => 'multiple spaces used when not suitable',
     'SIZEOFNOPAREN'    => 'use of sizeof without parentheses',
     'SNPRINTF'         => 'use of snprintf',
+    'ONELINECONDITION' => 'conditional block on the same line as the if()',
     );
 
 sub readwhitelist {
@@ -457,13 +458,34 @@ sub scanfile {
             }
         }
 
-        if($nostr =~ /^((.*)(if) *\()(.*)\)/) {
+        if($nostr =~ /^((.*\s)(if) *\()(.*)\)(.*)/) {
             my $pos = length($1);
-            if($4 =~ / = /) {
+            my $postparen = $5;
+            my $cond = $4;
+            if($cond =~ / = /) {
                 checkwarn("ASSIGNWITHINCONDITION",
                           $line, $pos+1, $file, $l,
                           "assignment within conditional expression");
             }
+            my $temp = $cond;
+            $temp =~ s/\(//g; # remove open parens
+            my $openc = length($cond) - length($temp);
+
+            $temp = $cond;
+            $temp =~ s/\)//g; # remove close parens
+            my $closec = length($cond) - length($temp);
+            my $even = $openc == $closec;
+
+            if($l =~ / *\#/) {
+                # this is a #if, treat it differently
+            }
+            elsif($even && $postparen &&
+               ($postparen !~ /^ *$/) && ($postparen !~ /^ *[,{&|\\]+/)) {
+                print STDERR "5: '$postparen'\n";
+                checkwarn("ONELINECONDITION",
+                          $line, length($l)-length($postparen), $file, $l,
+                          "conditional block on the same line");
+            }
         }
         # check spaces after open parentheses
         if($l =~ /^(.*[a-z])\( /i) {
diff --git a/lib/config-dos.h b/lib/config-dos.h
index aa83c4be..349e7563 100644
--- a/lib/config-dos.h
+++ b/lib/config-dos.h
@@ -151,8 +151,6 @@
   #define ssize_t  int
 #endif
 
-#define CURL_CA_BUNDLE  getenv("CURL_CA_BUNDLE")
-
 /* Target HAVE_x section */
 
 #if defined(DJGPP)
diff --git a/lib/config-os400.h b/lib/config-os400.h
index a302828e..7beb81fa 100644
--- a/lib/config-os400.h
+++ b/lib/config-os400.h
@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -97,9 +97,6 @@
 /* Define if you have the <crypto.h> header file. */
 #undef HAVE_CRYPTO_H
 
-/* Define if you have the <des.h> header file. */
-#undef HAVE_DES_H
-
 /* Define if you have the <errno.h> header file. */
 #define HAVE_ERRNO_H
 
diff --git a/lib/config-riscos.h b/lib/config-riscos.h
index 4af94981..0ddf487e 100644
--- a/lib/config-riscos.h
+++ b/lib/config-riscos.h
@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -98,9 +98,6 @@
 /* Define if you have the <crypto.h> header file. */
 #undef HAVE_CRYPTO_H
 
-/* Define if you have the <des.h> header file. */
-#undef HAVE_DES_H
-
 /* Define if you have the <errno.h> header file. */
 #define HAVE_ERRNO_H
 
diff --git a/lib/config-symbian.h b/lib/config-symbian.h
index 82a27bfe..7f17dce2 100644
--- a/lib/config-symbian.h
+++ b/lib/config-symbian.h
@@ -122,9 +122,6 @@
 /* Define to 1 if you have the <crypto.h> header file. */
 /* #undef HAVE_CRYPTO_H */
 
-/* Define to 1 if you have the <des.h> header file. */
-/* #undef HAVE_DES_H */
-
 /* Define to 1 if you have the <dlfcn.h> header file. */
 #define HAVE_DLFCN_H 1
 
diff --git a/lib/config-tpf.h b/lib/config-tpf.h
index a79afae6..199dfbcd 100644
--- a/lib/config-tpf.h
+++ b/lib/config-tpf.h
@@ -115,10 +115,6 @@
 /* #undef HAVE_CRYPTO_H */
 #define HAVE_CRYPTO_H 1
 
-/* Define to 1 if you have the <des.h> header file. */
-/* #undef HAVE_DES_H */
-#define HAVE_DES_H 1
-
 /* Define to 1 if you have the <errno.h> header file. */
 #define HAVE_ERRNO_H 1
 
diff --git a/lib/config-vxworks.h b/lib/config-vxworks.h
index 2769cdfd..14bf0be4 100644
--- a/lib/config-vxworks.h
+++ b/lib/config-vxworks.h
@@ -137,9 +137,6 @@
 /* Define to 1 if you have the <crypto.h> header file. */
 /* #undef HAVE_CRYPTO_H */
 
-/* Define to 1 if you have the <des.h> header file. */
-/* #undef HAVE_DES_H */
-
 /* Define to 1 if you have the <dlfcn.h> header file. */
 #define HAVE_DLFCN_H 1
 
diff --git a/lib/config-win32.h b/lib/config-win32.h
index d19665d7..516baca0 100644
--- a/lib/config-win32.h
+++ b/lib/config-win32.h
@@ -719,12 +719,15 @@ Vista
 #endif
 
 /* Define to use Unix sockets. */
-#if defined(_MSC_VER) && (_MSC_VER >= 1500)
-/* sdkddkver.h first shipped with Platform SDK v6.0A included with VS2008 */
-#include <sdkddkver.h>
-#if defined(NTDDI_WIN10_RS4)
 #define USE_UNIX_SOCKETS
-#endif
+#if !defined(UNIX_PATH_MAX)
+  /* Replicating logic present in afunix.h of newer Windows 10 SDK versions */
+# define UNIX_PATH_MAX 108
+# include <ws2tcpip.h>
+  typedef struct sockaddr_un {
+    ADDRESS_FAMILY sun_family;
+    char sun_path[UNIX_PATH_MAX];
+  } SOCKADDR_UN, *PSOCKADDR_UN;
 #endif
 
 /* ---------------------------------------------------------------- */
diff --git a/lib/connect.c b/lib/connect.c
index 0a7475cb..421f9041 100644
--- a/lib/connect.c
+++ b/lib/connect.c
@@ -167,11 +167,12 @@ tcpkeepalive(struct Curl_easy *data,
 static CURLcode
 singleipconnect(struct connectdata *conn,
                 const Curl_addrinfo *ai, /* start connecting to this */
-                int sockindex);          /* 0 or 1 among the temp ones */
+                int tempindex);          /* 0 or 1 among the temp ones */
 
 /*
  * Curl_timeleft() returns the amount of milliseconds left allowed for the
- * transfer/connection. If the value is negative, the timeout time has already
+ * transfer/connection. If the value is 0, there's no timeout (ie there's
+ * infinite time left). If the value is negative, the timeout time has already
  * elapsed.
  *
  * The start time is stored in progress.t_startsingle - as set with
@@ -555,13 +556,27 @@ static bool verifyconnect(curl_socket_t sockfd, int *error)
   return rc;
 }
 
+/* update tempaddr[tempindex] (to the next entry), makes sure to stick
+   to the correct family */
+static Curl_addrinfo *ainext(struct connectdata *conn,
+                             int tempindex,
+                             bool next) /* use current or next entry */
+{
+  Curl_addrinfo *ai = conn->tempaddr[tempindex];
+  if(ai && next)
+    ai = ai->ai_next;
+  while(ai && (ai->ai_family != conn->tempfamily[tempindex]))
+    ai = ai->ai_next;
+  conn->tempaddr[tempindex] = ai;
+  return ai;
+}
+
 /* Used within the multi interface. Try next IP address, return TRUE if no
    more address exists or error */
 static CURLcode trynextip(struct connectdata *conn,
                           int sockindex,
                           int tempindex)
 {
-  const int other = tempindex ^ 1;
   CURLcode result = CURLE_COULDNT_CONNECT;
 
   /* First clean up after the failed socket.
@@ -572,38 +587,15 @@ static CURLcode trynextip(struct connectdata *conn,
   conn->tempsock[tempindex] = CURL_SOCKET_BAD;
 
   if(sockindex == FIRSTSOCKET) {
-    Curl_addrinfo *ai = NULL;
-    int family = AF_UNSPEC;
-
-    if(conn->tempaddr[tempindex]) {
-      /* find next address in the same protocol family */
-      family = conn->tempaddr[tempindex]->ai_family;
-      ai = conn->tempaddr[tempindex]->ai_next;
-    }
-#ifdef ENABLE_IPV6
-    else if(conn->tempaddr[0]) {
-      /* happy eyeballs - try the other protocol family */
-      int firstfamily = conn->tempaddr[0]->ai_family;
-      family = (firstfamily == AF_INET) ? AF_INET6 : AF_INET;
-      ai = conn->tempaddr[0]->ai_next;
-    }
-#endif
+    Curl_addrinfo *ai = conn->tempaddr[tempindex];
 
     while(ai) {
-      if(conn->tempaddr[other]) {
-        /* we can safely skip addresses of the other protocol family */
-        while(ai && ai->ai_family != family)
-          ai = ai->ai_next;
-      }
-
       if(ai) {
         result = singleipconnect(conn, ai, tempindex);
         if(result == CURLE_COULDNT_CONNECT) {
-          ai = ai->ai_next;
+          ai = ainext(conn, tempindex, TRUE);
           continue;
         }
-
-        conn->tempaddr[tempindex] = ai;
       }
       break;
     }
@@ -688,58 +680,56 @@ bool Curl_addr2string(struct sockaddr *sa, curl_socklen_t salen,
    connection */
 void Curl_updateconninfo(struct connectdata *conn, curl_socket_t sockfd)
 {
-  if(conn->transport != TRNSPRT_TCP)
-    /* there's no TCP connection! */
-    return;
-
+  if(conn->transport == TRNSPRT_TCP) {
 #if defined(HAVE_GETPEERNAME) || defined(HAVE_GETSOCKNAME)
-  if(!conn->bits.reuse && !conn->bits.tcp_fastopen) {
-    struct Curl_easy *data = conn->data;
-    char buffer[STRERROR_LEN];
-    struct Curl_sockaddr_storage ssrem;
-    struct Curl_sockaddr_storage ssloc;
-    curl_socklen_t plen;
-    curl_socklen_t slen;
+    if(!conn->bits.reuse && !conn->bits.tcp_fastopen) {
+      struct Curl_easy *data = conn->data;
+      char buffer[STRERROR_LEN];
+      struct Curl_sockaddr_storage ssrem;
+      struct Curl_sockaddr_storage ssloc;
+      curl_socklen_t plen;
+      curl_socklen_t slen;
 #ifdef HAVE_GETPEERNAME
-    plen = sizeof(struct Curl_sockaddr_storage);
-    if(getpeername(sockfd, (struct sockaddr*) &ssrem, &plen)) {
-      int error = SOCKERRNO;
-      failf(data, "getpeername() failed with errno %d: %s",
-            error, Curl_strerror(error, buffer, sizeof(buffer)));
-      return;
-    }
+      plen = sizeof(struct Curl_sockaddr_storage);
+      if(getpeername(sockfd, (struct sockaddr*) &ssrem, &plen)) {
+        int error = SOCKERRNO;
+        failf(data, "getpeername() failed with errno %d: %s",
+              error, Curl_strerror(error, buffer, sizeof(buffer)));
+        return;
+      }
 #endif
 #ifdef HAVE_GETSOCKNAME
-    slen = sizeof(struct Curl_sockaddr_storage);
-    memset(&ssloc, 0, sizeof(ssloc));
-    if(getsockname(sockfd, (struct sockaddr*) &ssloc, &slen)) {
-      int error = SOCKERRNO;
-      failf(data, "getsockname() failed with errno %d: %s",
-            error, Curl_strerror(error, buffer, sizeof(buffer)));
-      return;
-    }
+      slen = sizeof(struct Curl_sockaddr_storage);
+      memset(&ssloc, 0, sizeof(ssloc));
+      if(getsockname(sockfd, (struct sockaddr*) &ssloc, &slen)) {
+        int error = SOCKERRNO;
+        failf(data, "getsockname() failed with errno %d: %s",
+              error, Curl_strerror(error, buffer, sizeof(buffer)));
+        return;
+      }
 #endif
 #ifdef HAVE_GETPEERNAME
-    if(!Curl_addr2string((struct sockaddr*)&ssrem, plen,
-                         conn->primary_ip, &conn->primary_port)) {
-      failf(data, "ssrem inet_ntop() failed with errno %d: %s",
-            errno, Curl_strerror(errno, buffer, sizeof(buffer)));
-      return;
-    }
-    memcpy(conn->ip_addr_str, conn->primary_ip, MAX_IPADR_LEN);
+      if(!Curl_addr2string((struct sockaddr*)&ssrem, plen,
+                           conn->primary_ip, &conn->primary_port)) {
+        failf(data, "ssrem inet_ntop() failed with errno %d: %s",
+              errno, Curl_strerror(errno, buffer, sizeof(buffer)));
+        return;
+      }
+      memcpy(conn->ip_addr_str, conn->primary_ip, MAX_IPADR_LEN);
 #endif
 #ifdef HAVE_GETSOCKNAME
-    if(!Curl_addr2string((struct sockaddr*)&ssloc, slen,
-                         conn->local_ip, &conn->local_port)) {
-      failf(data, "ssloc inet_ntop() failed with errno %d: %s",
-            errno, Curl_strerror(errno, buffer, sizeof(buffer)));
-      return;
-    }
+      if(!Curl_addr2string((struct sockaddr*)&ssloc, slen,
+                           conn->local_ip, &conn->local_port)) {
+        failf(data, "ssloc inet_ntop() failed with errno %d: %s",
+              errno, Curl_strerror(errno, buffer, sizeof(buffer)));
+        return;
+      }
 #endif
-  }
+    }
 #else /* !HAVE_GETSOCKNAME && !HAVE_GETPEERNAME */
-  (void)sockfd; /* unused */
+    (void)sockfd; /* unused */
 #endif
+  } /* end of TCP-only section */
 
   /* persist connection info in session handle */
   Curl_persistconninfo(conn);
@@ -816,6 +806,7 @@ static void post_SOCKS(struct connectdata *conn,
     Curl_pgrsTime(conn->data, TIMER_CONNECT); /* connect done */
   Curl_updateconninfo(conn, conn->sock[sockindex]);
   Curl_verboseconnect(conn);
+  conn->data->info.numconnects++; /* to track the number of connections made */
 }
 
 /*
@@ -880,6 +871,7 @@ CURLcode Curl_is_connected(struct connectdata *conn,
         conn->sock[sockindex] = conn->tempsock[i];
         conn->ip_addr = conn->tempaddr[i];
         conn->tempsock[i] = CURL_SOCKET_BAD;
+        post_SOCKS(conn, sockindex, connected);
         connkeep(conn, "HTTP/3 default");
       }
       return result;
@@ -905,9 +897,10 @@ CURLcode Curl_is_connected(struct connectdata *conn,
       }
 
       /* should we try another protocol family? */
-      if(i == 0 && conn->tempaddr[1] == NULL &&
+      if(i == 0 && !conn->parallel_connect &&
          (Curl_timediff(now, conn->connecttime) >=
           data->set.happy_eyeballs_timeout)) {
+        conn->parallel_connect = TRUE; /* starting now */
         trynextip(conn, sockindex, 1);
       }
     }
@@ -967,7 +960,7 @@ CURLcode Curl_is_connected(struct connectdata *conn,
 
         conn->timeoutms_per_addr = conn->tempaddr[i]->ai_next == NULL ?
           allow : allow / 2;
-
+        ainext(conn, i, TRUE);
         status = trynextip(conn, sockindex, i);
         if((status != CURLE_COULDNT_CONNECT) ||
            conn->tempsock[other] == CURL_SOCKET_BAD)
@@ -984,7 +977,7 @@ CURLcode Curl_is_connected(struct connectdata *conn,
 
     /* if the first address family runs out of addresses to try before
        the happy eyeball timeout, go ahead and try the next family now */
-    if(conn->tempaddr[1] == NULL) {
+    {
       result = trynextip(conn, sockindex, 1);
       if(!result)
         return result;
@@ -1113,7 +1106,7 @@ void Curl_sndbufset(curl_socket_t sockfd)
  */
 static CURLcode singleipconnect(struct connectdata *conn,
                                 const Curl_addrinfo *ai,
-                                int sockindex)
+                                int tempindex)
 {
   struct Curl_sockaddr_ex addr;
   int rc = -1;
@@ -1129,15 +1122,12 @@ static CURLcode singleipconnect(struct connectdata *conn,
   int optval = 1;
 #endif
   char buffer[STRERROR_LEN];
-  curl_socket_t *sockp = &conn->tempsock[sockindex];
+  curl_socket_t *sockp = &conn->tempsock[tempindex];
   *sockp = CURL_SOCKET_BAD;
 
   result = Curl_socket(conn, ai, &addr, &sockfd);
   if(result)
-    /* Failed to create the socket, but still return OK since we signal the
-       lack of socket as well. This allows the parent function to keep looping
-       over alternative addresses/socket families etc. */
-    return CURLE_OK;
+    return result;
 
   /* store remote address and port used in this connection attempt */
   if(!Curl_addr2string((struct sockaddr*)&addr.sa_addr, addr.addrlen,
@@ -1257,7 +1247,7 @@ static CURLcode singleipconnect(struct connectdata *conn,
     else if(conn->transport == TRNSPRT_QUIC) {
       /* pass in 'sockfd' separately since it hasn't been put into the
          tempsock array at this point */
-      result = Curl_quic_connect(conn, sockfd, sockindex,
+      result = Curl_quic_connect(conn, sockfd, tempindex,
                                  &addr.sa_addr, addr.addrlen);
       if(result)
         error = SOCKERRNO;
@@ -1315,7 +1305,7 @@ CURLcode Curl_connecthost(struct connectdata *conn,  /* context */
   struct Curl_easy *data = conn->data;
   struct curltime before = Curl_now();
   CURLcode result = CURLE_COULDNT_CONNECT;
-
+  int i;
   timediff_t timeout_ms = Curl_timeleft(data, &before, TRUE);
 
   if(timeout_ms < 0) {
@@ -1325,30 +1315,35 @@ CURLcode Curl_connecthost(struct connectdata *conn,  /* context */
   }
 
   conn->num_addr = Curl_num_addresses(remotehost->addr);
-  conn->tempaddr[0] = remotehost->addr;
-  conn->tempaddr[1] = NULL;
-  conn->tempsock[0] = CURL_SOCKET_BAD;
-  conn->tempsock[1] = CURL_SOCKET_BAD;
+  conn->tempaddr[0] = conn->tempaddr[1] = remotehost->addr;
+  conn->tempsock[0] = conn->tempsock[1] = CURL_SOCKET_BAD;
 
   /* Max time for the next connection attempt */
   conn->timeoutms_per_addr =
     conn->tempaddr[0]->ai_next == NULL ? timeout_ms : timeout_ms / 2;
 
-  /* start connecting to first IP */
-  while(conn->tempaddr[0]) {
-    result = singleipconnect(conn, conn->tempaddr[0], 0);
-    if(!result)
-      break;
-    conn->tempaddr[0] = conn->tempaddr[0]->ai_next;
-  }
+  conn->tempfamily[0] = conn->tempaddr[0]?
+    conn->tempaddr[0]->ai_family:0;
+  conn->tempfamily[1] = conn->tempfamily[0] == AF_INET6 ?
+    AF_INET : AF_INET6;
+  ainext(conn, 1, FALSE); /* assigns conn->tempaddr[1] accordingly */
 
-  if(conn->tempsock[0] == CURL_SOCKET_BAD) {
-    if(!result)
-      result = CURLE_COULDNT_CONNECT;
-    return result;
+  DEBUGF(infof(data, "family0 == %s, family1 == %s\n",
+               conn->tempfamily[0] == AF_INET ? "v4" : "v6",
+               conn->tempfamily[1] == AF_INET ? "v4" : "v6"));
+
+  /* get through the list in family order in case of quick failures */
+  for(i = 0; (i < 2) && result; i++) {
+    while(conn->tempaddr[i]) {
+      result = singleipconnect(conn, conn->tempaddr[i], i);
+      if(!result)
+        break;
+      ainext(conn, i, TRUE);
+    }
   }
+  if(result)
+    return result;
 
-  data->info.numconnects++; /* to track the number of connections made */
   Curl_expire(conn->data, data->set.happy_eyeballs_timeout,
               EXPIRE_HAPPY_EYEBALLS);
 
diff --git a/lib/curl_addrinfo.c b/lib/curl_addrinfo.c
index 16c4779c..b2dd8342 100644
--- a/lib/curl_addrinfo.c
+++ b/lib/curl_addrinfo.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -50,10 +50,6 @@
 #  define in_addr_t unsigned long
 #endif
 
-#if defined(WIN32) && defined(USE_UNIX_SOCKETS)
-#include <afunix.h>
-#endif
-
 #include <stddef.h>
 
 #include "curl_addrinfo.h"
diff --git a/lib/curl_config.h b/lib/curl_config.h
index e5b99a79..21cd2f89 100644
--- a/lib/curl_config.h
+++ b/lib/curl_config.h
@@ -97,6 +97,9 @@
 /* to disable verbose strings */
 /* #undef CURL_DISABLE_VERBOSE_STRINGS */
 
+/* to enable MQTT */
+/* #undef CURL_ENABLE_MQTT */
+
 /* Definition to make a library symbol externally visible. */
 #define CURL_EXTERN_SYMBOL __attribute__ ((__visibility__ ("default")))
 
@@ -299,16 +302,6 @@
 /* Define to 1 if you have a working gmtime_r function. */
 #define HAVE_GMTIME_R 1
 
-/* Define to 1 if you have the `gnutls_alpn_set_protocols' function. */
-/* #undef HAVE_GNUTLS_ALPN_SET_PROTOCOLS */
-
-/* Define to 1 if you have the `gnutls_certificate_set_x509_key_file2'
-   function. */
-/* #undef HAVE_GNUTLS_CERTIFICATE_SET_X509_KEY_FILE2 */
-
-/* Define to 1 if you have the `gnutls_ocsp_req_init' function. */
-/* #undef HAVE_GNUTLS_OCSP_REQ_INIT */
-
 /* if you have the function gnutls_srp_verifier */
 /* #undef HAVE_GNUTLS_SRP */
 
@@ -503,6 +496,9 @@
    */
 /* #undef HAVE_OLD_GSSMIT */
 
+/* Define to 1 if using OpenSSL 3 or later. */
+/* #undef HAVE_OPENSSL3 */
+
 /* Define to 1 if you have the <openssl/crypto.h> header file. */
 #define HAVE_OPENSSL_CRYPTO_H 1
 
@@ -989,6 +985,9 @@
 /* if ngtcp2 is in use */
 /* #undef USE_NGTCP2 */
 
+/* if ngtcp2_crypto_gnutls is in use */
+/* #undef USE_NGTCP2_CRYPTO_GNUTLS */
+
 /* if ngtcp2_crypto_openssl is in use */
 /* #undef USE_NGTCP2_CRYPTO_OPENSSL */
 
diff --git a/lib/curl_config.h.cmake b/lib/curl_config.h.cmake
index 98cdf514..57a86e50 100644
--- a/lib/curl_config.h.cmake
+++ b/lib/curl_config.h.cmake
@@ -1,3 +1,24 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
 /* lib/curl_config.h.in.  Generated somehow by cmake.  */
 
 /* when building libcurl itself */
@@ -42,6 +63,9 @@
 /* to disable LDAPS */
 #cmakedefine CURL_DISABLE_LDAPS 1
 
+/* to enable MQTT */
+#undef CURL_ENABLE_MQTT
+
 /* to disable POP3 */
 #cmakedefine CURL_DISABLE_POP3 1
 
@@ -145,9 +169,6 @@
 /* Define to 1 if you have the <crypto.h> header file. */
 #cmakedefine HAVE_CRYPTO_H 1
 
-/* Define to 1 if you have the <des.h> header file. */
-#cmakedefine HAVE_DES_H 1
-
 /* Define to 1 if you have the <dlfcn.h> header file. */
 #cmakedefine HAVE_DLFCN_H 1
 
@@ -945,6 +966,9 @@ ${SIZEOF_TIME_T_CODE}
 /* if BearSSL is enabled */
 #cmakedefine USE_BEARSSL 1
 
+/* if WolfSSL is enabled */
+#cmakedefine USE_WOLFSSL 1
+
 /* if libSSH2 is in use */
 #cmakedefine USE_LIBSSH2 1
 
diff --git a/lib/curl_config.h.in b/lib/curl_config.h.in
index 8f29f51c..abb6c078 100644
--- a/lib/curl_config.h.in
+++ b/lib/curl_config.h.in
@@ -96,6 +96,9 @@
 /* to disable verbose strings */
 #undef CURL_DISABLE_VERBOSE_STRINGS
 
+/* to enable MQTT */
+#undef CURL_ENABLE_MQTT
+
 /* Definition to make a library symbol externally visible. */
 #undef CURL_EXTERN_SYMBOL
 
@@ -298,16 +301,6 @@
 /* Define to 1 if you have a working gmtime_r function. */
 #undef HAVE_GMTIME_R
 
-/* Define to 1 if you have the `gnutls_alpn_set_protocols' function. */
-#undef HAVE_GNUTLS_ALPN_SET_PROTOCOLS
-
-/* Define to 1 if you have the `gnutls_certificate_set_x509_key_file2'
-   function. */
-#undef HAVE_GNUTLS_CERTIFICATE_SET_X509_KEY_FILE2
-
-/* Define to 1 if you have the `gnutls_ocsp_req_init' function. */
-#undef HAVE_GNUTLS_OCSP_REQ_INIT
-
 /* if you have the function gnutls_srp_verifier */
 #undef HAVE_GNUTLS_SRP
 
@@ -502,6 +495,9 @@
    */
 #undef HAVE_OLD_GSSMIT
 
+/* Define to 1 if using OpenSSL 3 or later. */
+#undef HAVE_OPENSSL3
+
 /* Define to 1 if you have the <openssl/crypto.h> header file. */
 #undef HAVE_OPENSSL_CRYPTO_H
 
@@ -1006,6 +1002,9 @@
 /* if ngtcp2 is in use */
 #undef USE_NGTCP2
 
+/* if ngtcp2_crypto_gnutls is in use */
+#undef USE_NGTCP2_CRYPTO_GNUTLS
+
 /* if ngtcp2_crypto_openssl is in use */
 #undef USE_NGTCP2_CRYPTO_OPENSSL
 
diff --git a/lib/curl_ntlm_core.c b/lib/curl_ntlm_core.c
index f9b823b4..32e29a93 100644
--- a/lib/curl_ntlm_core.c
+++ b/lib/curl_ntlm_core.c
@@ -342,7 +342,7 @@ static bool encrypt_des(const unsigned char *in, unsigned char *out,
 
   /* Acquire the crypto provider */
   if(!CryptAcquireContext(&hprov, NULL, NULL, PROV_RSA_FULL,
-                          CRYPT_VERIFYCONTEXT))
+                          CRYPT_VERIFYCONTEXT | CRYPT_SILENT))
     return FALSE;
 
   /* Setup the key blob structure */
diff --git a/lib/curl_setup.h b/lib/curl_setup.h
index 4ecda6a9..56e6db83 100644
--- a/lib/curl_setup.h
+++ b/lib/curl_setup.h
@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -231,64 +231,20 @@
 #endif
 
 /*
- * Use getaddrinfo to resolve the IPv4 address literal. If the current network
- * interface doesn't support IPv4, but supports IPv6, NAT64, and DNS64,
- * performing this task will result in a synthesized IPv6 address.
- */
-#ifdef  __APPLE__
-#define USE_RESOLVE_ON_IPS 1
-#endif
-
-/*
- * Include header files for windows builds before redefining anything.
- * Use this preprocessor block only to include or exclude windows.h,
- * winsock2.h, ws2tcpip.h or winsock.h. Any other windows thing belongs
- * to any other further and independent block.  Under Cygwin things work
- * just as under linux (e.g. <sys/socket.h>) and the winsock headers should
- * never be included when __CYGWIN__ is defined.  configure script takes
- * care of this, not defining HAVE_WINDOWS_H, HAVE_WINSOCK_H, HAVE_WINSOCK2_H,
- * neither HAVE_WS2TCPIP_H when __CYGWIN__ is defined.
+ * Windows setup file includes some system headers.
  */
 
 #ifdef HAVE_WINDOWS_H
-#  if defined(UNICODE) && !defined(_UNICODE)
-#    define _UNICODE
-#  endif
-#  if defined(_UNICODE) && !defined(UNICODE)
-#    define UNICODE
-#  endif
-#  include <winerror.h>
-#  include <windows.h>
-#  ifdef HAVE_WINSOCK2_H
-#    include <winsock2.h>
-#    ifdef HAVE_WS2TCPIP_H
-#      include <ws2tcpip.h>
-#    endif
-#  else
-#    ifdef HAVE_WINSOCK_H
-#      include <winsock.h>
-#    endif
-#  endif
-#  include <tchar.h>
-#  ifdef UNICODE
-     typedef wchar_t *(*curl_wcsdup_callback)(const wchar_t *str);
-#  endif
+#  include "setup-win32.h"
 #endif
 
 /*
- * Define USE_WINSOCK to 2 if we have and use WINSOCK2 API, else
- * define USE_WINSOCK to 1 if we have and use WINSOCK  API, else
- * undefine USE_WINSOCK.
+ * Use getaddrinfo to resolve the IPv4 address literal. If the current network
+ * interface doesn't support IPv4, but supports IPv6, NAT64, and DNS64,
+ * performing this task will result in a synthesized IPv6 address.
  */
-
-#undef USE_WINSOCK
-
-#ifdef HAVE_WINSOCK2_H
-#  define USE_WINSOCK 2
-#else
-#  ifdef HAVE_WINSOCK_H
-#    define USE_WINSOCK 1
-#  endif
+#ifdef  __APPLE__
+#define USE_RESOLVE_ON_IPS 1
 #endif
 
 #ifdef USE_LWIPSOCK
diff --git a/lib/dict.c b/lib/dict.c
index 208a2336..c802deef 100644
--- a/lib/dict.c
+++ b/lib/dict.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -46,6 +46,8 @@
 
 #ifdef HAVE_SYS_SELECT_H
 #include <sys/select.h>
+#elif defined(HAVE_UNISTD_H)
+#include <unistd.h>
 #endif
 
 #include "urldata.h"
diff --git a/lib/doh.c b/lib/doh.c
index aaa8f15c..10867cc3 100644
--- a/lib/doh.c
+++ b/lib/doh.c
@@ -174,7 +174,7 @@ UNITTEST DOHcode doh_encode(const char *host,
 }
 
 static size_t
-doh_write_cb(void *contents, size_t size, size_t nmemb, void *userp)
+doh_write_cb(const void *contents, size_t size, size_t nmemb, void *userp)
 {
   size_t realsize = size * nmemb;
   struct dohresponse *mem = (struct dohresponse *)userp;
@@ -318,6 +318,9 @@ static CURLcode dohprobe(struct Curl_easy *data,
     }
     if(data->set.proxy_ssl.no_revoke)
       ERROR_CHECK_SETOPT(CURLOPT_PROXY_SSL_OPTIONS, CURLSSLOPT_NO_REVOKE);
+    else if(data->set.proxy_ssl.revoke_best_effort)
+      ERROR_CHECK_SETOPT(CURLOPT_PROXY_SSL_OPTIONS,
+                         CURLSSLOPT_REVOKE_BEST_EFFORT);
     if(data->set.str[STRING_SSL_CAPATH_PROXY]) {
       ERROR_CHECK_SETOPT(CURLOPT_PROXY_CAPATH,
         data->set.str[STRING_SSL_CAPATH_PROXY]);
@@ -351,6 +354,8 @@ static CURLcode dohprobe(struct Curl_easy *data,
     }
     if(data->set.ssl.no_revoke)
       ERROR_CHECK_SETOPT(CURLOPT_SSL_OPTIONS, CURLSSLOPT_NO_REVOKE);
+    else if(data->set.ssl.revoke_best_effort)
+      ERROR_CHECK_SETOPT(CURLOPT_SSL_OPTIONS, CURLSSLOPT_REVOKE_BEST_EFFORT);
     if(data->set.ssl.fsslctx)
       ERROR_CHECK_SETOPT(CURLOPT_SSL_CTX_FUNCTION, data->set.ssl.fsslctx);
     if(data->set.ssl.fsslctxp)
@@ -434,7 +439,7 @@ Curl_addrinfo *Curl_doh(struct connectdata *conn,
   return NULL;
 }
 
-static DOHcode skipqname(unsigned char *doh, size_t dohlen,
+static DOHcode skipqname(const unsigned char *doh, size_t dohlen,
                          unsigned int *indexp)
 {
   unsigned char length;
@@ -458,12 +463,12 @@ static DOHcode skipqname(unsigned char *doh, size_t dohlen,
   return DOH_OK;
 }
 
-static unsigned short get16bit(unsigned char *doh, int index)
+static unsigned short get16bit(const unsigned char *doh, int index)
 {
   return (unsigned short)((doh[index] << 8) | doh[index + 1]);
 }
 
-static unsigned int get32bit(unsigned char *doh, int index)
+static unsigned int get32bit(const unsigned char *doh, int index)
 {
    /* make clang and gcc optimize this to bswap by incrementing
       the pointer first. */
@@ -475,7 +480,7 @@ static unsigned int get32bit(unsigned char *doh, int index)
   return ( (unsigned)doh[0] << 24) | (doh[1] << 16) |(doh[2] << 8) | doh[3];
 }
 
-static DOHcode store_a(unsigned char *doh, int index, struct dohentry *d)
+static DOHcode store_a(const unsigned char *doh, int index, struct dohentry *d)
 {
   /* silently ignore addresses over the limit */
   if(d->numaddr < DOH_MAX_ADDR) {
@@ -487,7 +492,9 @@ static DOHcode store_a(unsigned char *doh, int index, struct dohentry *d)
   return DOH_OK;
 }
 
-static DOHcode store_aaaa(unsigned char *doh, int index, struct dohentry *d)
+static DOHcode store_aaaa(const unsigned char *doh,
+                          int index,
+                          struct dohentry *d)
 {
   /* silently ignore addresses over the limit */
   if(d->numaddr < DOH_MAX_ADDR) {
@@ -500,7 +507,7 @@ static DOHcode store_aaaa(unsigned char *doh, int index, struct dohentry *d)
 }
 
 static DOHcode cnameappend(struct cnamestore *c,
-                           unsigned char *src,
+                           const unsigned char *src,
                            size_t len)
 {
   if(!c->alloc) {
@@ -525,7 +532,7 @@ static DOHcode cnameappend(struct cnamestore *c,
   return DOH_OK;
 }
 
-static DOHcode store_cname(unsigned char *doh,
+static DOHcode store_cname(const unsigned char *doh,
                            size_t dohlen,
                            unsigned int index,
                            struct dohentry *d)
@@ -580,7 +587,7 @@ static DOHcode store_cname(unsigned char *doh,
   return DOH_OK;
 }
 
-static DOHcode rdata(unsigned char *doh,
+static DOHcode rdata(const unsigned char *doh,
                      size_t dohlen,
                      unsigned short rdlength,
                      unsigned short type,
@@ -630,7 +637,7 @@ static void init_dohentry(struct dohentry *de)
 }
 
 
-UNITTEST DOHcode doh_decode(unsigned char *doh,
+UNITTEST DOHcode doh_decode(const unsigned char *doh,
                             size_t dohlen,
                             DNStype dnstype,
                             struct dohentry *d)
@@ -770,12 +777,12 @@ UNITTEST DOHcode doh_decode(unsigned char *doh,
 
 #ifndef CURL_DISABLE_VERBOSE_STRINGS
 static void showdoh(struct Curl_easy *data,
-                    struct dohentry *d)
+                    const struct dohentry *d)
 {
   int i;
   infof(data, "TTL: %u seconds\n", d->ttl);
   for(i = 0; i < d->numaddr; i++) {
-    struct dohaddr *a = &d->addr[i];
+    const struct dohaddr *a = &d->addr[i];
     if(a->type == DNS_TYPE_A) {
       infof(data, "DOH A: %u.%u.%u.%u\n",
             a->ip.v4[0], a->ip.v4[1],
diff --git a/lib/doh.h b/lib/doh.h
index fc053edd..f6154ffd 100644
--- a/lib/doh.h
+++ b/lib/doh.h
@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 2018 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 2018 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -99,7 +99,7 @@ DOHcode doh_encode(const char *host,
                    unsigned char *dnsp, /* buffer */
                    size_t len,  /* buffer size */
                    size_t *olen); /* output length */
-DOHcode doh_decode(unsigned char *doh,
+DOHcode doh_decode(const unsigned char *doh,
                    size_t dohlen,
                    DNStype dnstype,
                    struct dohentry *d);
diff --git a/lib/easy.c b/lib/easy.c
index b648e80c..d08c6066 100644
--- a/lib/easy.c
+++ b/lib/easy.c
@@ -884,14 +884,25 @@ struct Curl_easy *curl_easy_duphandle(struct Curl_easy *data)
     goto fail;
 
 #ifdef USE_ARES
-  if(Curl_set_dns_servers(outcurl, data->set.str[STRING_DNS_SERVERS]))
-    goto fail;
-  if(Curl_set_dns_interface(outcurl, data->set.str[STRING_DNS_INTERFACE]))
-    goto fail;
-  if(Curl_set_dns_local_ip4(outcurl, data->set.str[STRING_DNS_LOCAL_IP4]))
-    goto fail;
-  if(Curl_set_dns_local_ip6(outcurl, data->set.str[STRING_DNS_LOCAL_IP6]))
-    goto fail;
+  {
+    CURLcode rc;
+
+    rc = Curl_set_dns_servers(outcurl, data->set.str[STRING_DNS_SERVERS]);
+    if(rc && rc != CURLE_NOT_BUILT_IN)
+      goto fail;
+
+    rc = Curl_set_dns_interface(outcurl, data->set.str[STRING_DNS_INTERFACE]);
+    if(rc && rc != CURLE_NOT_BUILT_IN)
+      goto fail;
+
+    rc = Curl_set_dns_local_ip4(outcurl, data->set.str[STRING_DNS_LOCAL_IP4]);
+    if(rc && rc != CURLE_NOT_BUILT_IN)
+      goto fail;
+
+    rc = Curl_set_dns_local_ip6(outcurl, data->set.str[STRING_DNS_LOCAL_IP6]);
+    if(rc && rc != CURLE_NOT_BUILT_IN)
+      goto fail;
+  }
 #endif /* USE_ARES */
 
   Curl_convert_setup(outcurl);
diff --git a/lib/file.c b/lib/file.c
index 24923707..576a7946 100644
--- a/lib/file.c
+++ b/lib/file.c
@@ -136,7 +136,7 @@ static CURLcode file_connect(struct connectdata *conn, bool *done)
   struct Curl_easy *data = conn->data;
   char *real_path;
   struct FILEPROTO *file = data->req.protop;
-  int fd = -1;
+  int fd;
 #ifdef DOS_FILESYSTEM
   size_t i;
   char *actual_path;
@@ -181,9 +181,7 @@ static CURLcode file_connect(struct connectdata *conn, bool *done)
       return CURLE_URL_MALFORMAT;
     }
 
-  if(strncmp("\\\\", actual_path, 2))
-    /* refuse to open path that starts with two backslashes */
-    fd = open_readonly(actual_path, O_RDONLY|O_BINARY);
+  fd = open_readonly(actual_path, O_RDONLY|O_BINARY);
   file->path = actual_path;
 #else
   if(memchr(real_path, 0, real_path_len)) {
diff --git a/lib/firefox-db2pem.sh b/lib/firefox-db2pem.sh
index 45489324..ee820261 100644
--- a/lib/firefox-db2pem.sh
+++ b/lib/firefox-db2pem.sh
@@ -6,7 +6,7 @@
 # *                            | (__| |_| |  _ <| |___
 # *                             \___|\___/|_| \_\_____|
 # *
-# * Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel@haxx.se>, et al.
+# * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
 # *
 # * This software is licensed as described in the file COPYING, which
 # * you should have received as part of this distribution. The terms
diff --git a/lib/ftp.h b/lib/ftp.h
index 984347f2..06421c6a 100644
--- a/lib/ftp.h
+++ b/lib/ftp.h
@@ -150,7 +150,6 @@ struct ftp_conn {
      connection to */
   char *newhost;          /* this is the pair to connect the DATA... */
   unsigned short newport; /* connection to */
-
 };
 
 #define DEFAULT_ACCEPT_TIMEOUT   60000 /* milliseconds == one minute */
diff --git a/lib/getinfo.c b/lib/getinfo.c
index 2b8f2303..84d9fc1c 100644
--- a/lib/getinfo.c
+++ b/lib/getinfo.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -147,6 +147,33 @@ static CURLcode getinfo_long(struct Curl_easy *data, CURLINFO info,
     long          *to_long;
   } lptr;
 
+#ifdef DEBUGBUILD
+  char *timestr = getenv("CURL_TIME");
+  if(timestr) {
+    unsigned long val = strtol(timestr, NULL, 10);
+    switch(info) {
+    case CURLINFO_LOCAL_PORT:
+      *param_longp = (long)val;
+      return CURLE_OK;
+    default:
+      break;
+    }
+  }
+  /* use another variable for this to allow different values */
+  timestr = getenv("CURL_DEBUG_SIZE");
+  if(timestr) {
+    unsigned long val = strtol(timestr, NULL, 10);
+    switch(info) {
+    case CURLINFO_HEADER_SIZE:
+    case CURLINFO_REQUEST_SIZE:
+      *param_longp = (long)val;
+      return CURLE_OK;
+    default:
+      break;
+    }
+  }
+#endif
+
   switch(info) {
   case CURLINFO_RESPONSE_CODE:
     *param_longp = data->info.httpcode;
@@ -212,8 +239,11 @@ static CURLcode getinfo_long(struct Curl_easy *data, CURLINFO info,
     *param_longp = data->info.conn_local_port;
     break;
   case CURLINFO_CONDITION_UNMET:
-    /* return if the condition prevented the document to get transferred */
-    *param_longp = data->info.timecond ? 1L : 0L;
+    if(data->info.httpcode == 304)
+      *param_longp = 1L;
+    else
+      /* return if the condition prevented the document to get transferred */
+      *param_longp = data->info.timecond ? 1L : 0L;
     break;
   case CURLINFO_RTSP_CLIENT_CSEQ:
     *param_longp = data->state.rtsp_next_client_CSeq;
@@ -258,6 +288,27 @@ static CURLcode getinfo_long(struct Curl_easy *data, CURLINFO info,
 static CURLcode getinfo_offt(struct Curl_easy *data, CURLINFO info,
                              curl_off_t *param_offt)
 {
+#ifdef DEBUGBUILD
+  char *timestr = getenv("CURL_TIME");
+  if(timestr) {
+    unsigned long val = strtol(timestr, NULL, 10);
+    switch(info) {
+    case CURLINFO_TOTAL_TIME_T:
+    case CURLINFO_NAMELOOKUP_TIME_T:
+    case CURLINFO_CONNECT_TIME_T:
+    case CURLINFO_APPCONNECT_TIME_T:
+    case CURLINFO_PRETRANSFER_TIME_T:
+    case CURLINFO_STARTTRANSFER_TIME_T:
+    case CURLINFO_REDIRECT_TIME_T:
+    case CURLINFO_SPEED_DOWNLOAD_T:
+    case CURLINFO_SPEED_UPLOAD_T:
+      *param_offt = (curl_off_t)val;
+      return CURLE_OK;
+    default:
+      break;
+    }
+  }
+#endif
   switch(info) {
   case CURLINFO_FILETIME_T:
     *param_offt = (curl_off_t)data->info.filetime;
@@ -282,7 +333,7 @@ static CURLcode getinfo_offt(struct Curl_easy *data, CURLINFO info,
     *param_offt = (data->progress.flags & PGRS_UL_SIZE_KNOWN)?
       data->progress.size_ul:-1;
     break;
-  case CURLINFO_TOTAL_TIME_T:
+   case CURLINFO_TOTAL_TIME_T:
     *param_offt = data->progress.timespent;
     break;
   case CURLINFO_NAMELOOKUP_TIME_T:
@@ -316,6 +367,27 @@ static CURLcode getinfo_offt(struct Curl_easy *data, CURLINFO info,
 static CURLcode getinfo_double(struct Curl_easy *data, CURLINFO info,
                                double *param_doublep)
 {
+#ifdef DEBUGBUILD
+  char *timestr = getenv("CURL_TIME");
+  if(timestr) {
+    unsigned long val = strtol(timestr, NULL, 10);
+    switch(info) {
+    case CURLINFO_TOTAL_TIME:
+    case CURLINFO_NAMELOOKUP_TIME:
+    case CURLINFO_CONNECT_TIME:
+    case CURLINFO_APPCONNECT_TIME:
+    case CURLINFO_PRETRANSFER_TIME:
+    case CURLINFO_STARTTRANSFER_TIME:
+    case CURLINFO_REDIRECT_TIME:
+    case CURLINFO_SPEED_DOWNLOAD:
+    case CURLINFO_SPEED_UPLOAD:
+      *param_doublep = (double)val;
+      return CURLE_OK;
+    default:
+      break;
+    }
+  }
+#endif
   switch(info) {
   case CURLINFO_TOTAL_TIME:
     *param_doublep = DOUBLE_SECS(data->progress.timespent);
diff --git a/lib/gopher.c b/lib/gopher.c
index b296c62d..c48098f7 100644
--- a/lib/gopher.c
+++ b/lib/gopher.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -28,6 +28,7 @@
 #include <curl/curl.h>
 #include "transfer.h"
 #include "sendf.h"
+#include "connect.h"
 #include "progress.h"
 #include "gopher.h"
 #include "select.h"
@@ -83,8 +84,10 @@ static CURLcode gopher_do(struct connectdata *conn, bool *done)
   char *query = data->state.up.query;
   char *sel = NULL;
   char *sel_org = NULL;
+  timediff_t timeout_ms;
   ssize_t amount, k;
   size_t len;
+  int what;
 
   *done = TRUE; /* unconditionally */
 
@@ -139,19 +142,29 @@ static CURLcode gopher_do(struct connectdata *conn, bool *done)
     else
       break;
 
+    timeout_ms = Curl_timeleft(conn->data, NULL, FALSE);
+    if(timeout_ms < 0) {
+      result = CURLE_OPERATION_TIMEDOUT;
+      break;
+    }
+    if(!timeout_ms)
+      timeout_ms = TIMEDIFF_T_MAX;
+
     /* Don't busyloop. The entire loop thing is a work-around as it causes a
        BLOCKING behavior which is a NO-NO. This function should rather be
        split up in a do and a doing piece where the pieces that aren't
        possible to send now will be sent in the doing function repeatedly
        until the entire request is sent.
-
-       Wait a while for the socket to be writable. Note that this doesn't
-       acknowledge the timeout.
     */
-    if(SOCKET_WRITABLE(sockfd, 100) < 0) {
+    what = SOCKET_WRITABLE(sockfd, timeout_ms);
+    if(what < 0) {
       result = CURLE_SEND_ERROR;
       break;
     }
+    else if(!what) {
+      result = CURLE_OPERATION_TIMEDOUT;
+      break;
+    }
   }
 
   free(sel_org);
diff --git a/lib/http.c b/lib/http.c
index bff3adc1..c3f7c350 100644
--- a/lib/http.c
+++ b/lib/http.c
@@ -1229,8 +1229,21 @@ CURLcode Curl_add_buffer_send(Curl_send_buffer **inp,
     memcpy(data->state.ulbuf, ptr, sendsize);
     ptr = data->state.ulbuf;
   }
-  else
+  else {
+#ifdef CURLDEBUG
+    /* Allow debug builds override this logic to force short initial sends */
+    char *p = getenv("CURL_SMALLREQSEND");
+    if(p) {
+      size_t altsize = (size_t)strtoul(p, NULL, 10);
+      if(altsize)
+        sendsize = CURLMIN(size, altsize);
+      else
+        sendsize = size;
+    }
+    else
+#endif
     sendsize = size;
+  }
 
   result = Curl_write(conn, sockfd, ptr, sendsize, &amount);
 
@@ -1320,7 +1333,6 @@ CURLcode Curl_add_bufferf(Curl_send_buffer **inp, const char *fmt, ...)
 {
   char *s;
   va_list ap;
-  Curl_send_buffer *in = *inp;
   va_start(ap, fmt);
   s = vaprintf(fmt, ap); /* this allocs a new string to append */
   va_end(ap);
@@ -1331,9 +1343,7 @@ CURLcode Curl_add_bufferf(Curl_send_buffer **inp, const char *fmt, ...)
     return result;
   }
   /* If we failed, we cleanup the whole buffer and return error */
-  free(in->buffer);
-  free(in);
-  *inp = NULL;
+  Curl_add_buffer_free(inp);
   return CURLE_OUT_OF_MEMORY;
 }
 
@@ -1350,9 +1360,7 @@ CURLcode Curl_add_buffer(Curl_send_buffer **inp, const void *inptr,
     /* If resulting used size of send buffer would wrap size_t, cleanup
        the whole buffer and return error. Otherwise the required buffer
        size will fit into a single allocatable memory chunk */
-    Curl_safefree(in->buffer);
-    free(in);
-    *inp = NULL;
+    Curl_add_buffer_free(inp);
     return CURLE_OUT_OF_MEMORY;
   }
 
@@ -2602,8 +2610,10 @@ CURLcode Curl_http(struct connectdata *conn, bool *done)
   if(conn->bits.altused && !Curl_checkheaders(conn, "Alt-Used")) {
     altused = aprintf("Alt-Used: %s:%d\r\n",
                       conn->conn_to_host.name, conn->conn_to_port);
-    if(!altused)
+    if(!altused) {
+      Curl_add_buffer_free(&req_buffer);
       return CURLE_OUT_OF_MEMORY;
+    }
   }
 #endif
   result =
@@ -3044,7 +3054,7 @@ CURLcode Curl_http(struct connectdata *conn, bool *done)
   }
   if(result)
     return result;
-  if(!postsize)
+  if(!postsize && (http->sending != HTTPSEND_REQUEST))
     data->req.upload_done = TRUE;
 
   if(data->req.writebytecount) {
diff --git a/lib/http2.c b/lib/http2.c
index 41d8db68..93dfbdb7 100644
--- a/lib/http2.c
+++ b/lib/http2.c
@@ -1727,8 +1727,6 @@ static ssize_t http2_recv(struct connectdata *conn, int sockindex,
 
     return retlen;
   }
-  /* If this stream is closed, return 0 to signal the http routine to close
-     the connection */
   if(stream->closed)
     return 0;
   *err = CURLE_AGAIN;
diff --git a/lib/if2ip.c b/lib/if2ip.c
index d003de67..b283f67f 100644
--- a/lib/if2ip.c
+++ b/lib/if2ip.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -129,11 +129,11 @@ if2ip_result_t Curl_if2ip(int af, unsigned int remote_scope,
               unsigned int ifscope = Curl_ipv6_scope(iface->ifa_addr);
 
               if(ifscope != remote_scope) {
-                /* We are interested only in interface addresses whose
-                   scope matches the remote address we want to
-                   connect to: global for global, link-local for
-                   link-local, etc... */
-                if(res == IF2IP_NOT_FOUND) res = IF2IP_AF_NOT_SUPPORTED;
+                /* We are interested only in interface addresses whose scope
+                   matches the remote address we want to connect to: global
+                   for global, link-local for link-local, etc... */
+                if(res == IF2IP_NOT_FOUND)
+                  res = IF2IP_AF_NOT_SUPPORTED;
                 continue;
               }
 
diff --git a/lib/libcurl.plist b/lib/libcurl.plist
index 0b521b0f..a02dfaa7 100644
--- a/lib/libcurl.plist
+++ b/lib/libcurl.plist
@@ -15,7 +15,7 @@
 	<string>se.haxx.curl.libcurl</string>
 
 	<key>CFBundleVersion</key>
-	<string>7.69.1</string>
+	<string>7.70.0</string>
 
 	<key>CFBundleName</key>
 	<string>libcurl</string>
@@ -27,9 +27,9 @@
 	<string>????</string>
 
 	<key>CFBundleShortVersionString</key>
-	<string>libcurl 7.69.1</string>
+	<string>libcurl 7.70.0</string>
 
 	<key>CFBundleGetInfoString</key>
-	<string>libcurl.plist 7.69.1</string>
+	<string>libcurl.plist 7.70.0</string>
 </dict>
 </plist>
diff --git a/lib/makefile.amiga b/lib/makefile.amiga
index 673b147c..29df6543 100644
--- a/lib/makefile.amiga
+++ b/lib/makefile.amiga
@@ -1,3 +1,24 @@
+#***************************************************************************
+#                                  _   _ ____  _
+#  Project                     ___| | | |  _ \| |
+#                             / __| | | | |_) | |
+#                            | (__| |_| |  _ <| |___
+#                             \___|\___/|_| \_\_____|
+#
+# Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
+#
+# This software is licensed as described in the file COPYING, which
+# you should have received as part of this distribution. The terms
+# are also available at https://curl.haxx.se/docs/copyright.html.
+#
+# You may opt to use, copy, modify, merge, publish, distribute and/or sell
+# copies of the Software, and permit persons to whom the Software is
+# furnished to do so, under the terms of the COPYING file.
+#
+# This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+# KIND, either express or implied.
+#
+###########################################################################
 #
 # libcurl Makefile for AmigaOS ...
 #
diff --git a/lib/makefile.dj b/lib/makefile.dj
index 941f8ce6..6ea79e4b 100644
--- a/lib/makefile.dj
+++ b/lib/makefile.dj
@@ -6,7 +6,7 @@
 #                             \___|\___/|_| \_\_____|
 #
 # Copyright (C) 2003 - 2008, Gisle Vanem <gvanem@yahoo.no>.
-# Copyright (C) 2003 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
+# Copyright (C) 2003 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
 #
 # This software is licensed as described in the file COPYING, which
 # you should have received as part of this distribution. The terms
diff --git a/lib/md4.c b/lib/md4.c
index 38f1b2bc..10e6fc53 100644
--- a/lib/md4.c
+++ b/lib/md4.c
@@ -29,6 +29,10 @@
 
 #ifdef USE_OPENSSL
 #include <openssl/opensslconf.h>
+#if defined(OPENSSL_VERSION_MAJOR) && (OPENSSL_VERSION_MAJOR >= 3)
+/* OpenSSL 3.0.0 marks the MD4 functions as deprecated */
+#define OPENSSL_NO_MD4
+#endif
 #endif /* USE_OPENSSL */
 
 #ifdef USE_MBEDTLS
@@ -146,7 +150,7 @@ static void MD4_Init(MD4_CTX *ctx)
   ctx->hHash = 0;
 
   if(CryptAcquireContext(&ctx->hCryptProv, NULL, NULL, PROV_RSA_FULL,
-                         CRYPT_VERIFYCONTEXT)) {
+                         CRYPT_VERIFYCONTEXT | CRYPT_SILENT)) {
     CryptCreateHash(ctx->hCryptProv, CALG_MD4, 0, 0, &ctx->hHash);
   }
 }
diff --git a/lib/md5.c b/lib/md5.c
index 3f601b3a..76615878 100644
--- a/lib/md5.c
+++ b/lib/md5.c
@@ -186,8 +186,8 @@ typedef struct {
 
 static void MD5_Init(MD5_CTX *ctx)
 {
-  if(CryptAcquireContext(&ctx->hCryptProv, NULL, NULL,
-                         PROV_RSA_FULL, CRYPT_VERIFYCONTEXT)) {
+  if(CryptAcquireContext(&ctx->hCryptProv, NULL, NULL, PROV_RSA_FULL,
+                         CRYPT_VERIFYCONTEXT | CRYPT_SILENT)) {
     CryptCreateHash(ctx->hCryptProv, CALG_MD5, 0, 0, &ctx->hHash);
   }
 }
diff --git a/lib/memdebug.c b/lib/memdebug.c
index ede60094..1c6b1514 100644
--- a/lib/memdebug.c
+++ b/lib/memdebug.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -328,7 +328,7 @@ void curl_dbg_free(void *ptr, int line, const char *source)
     (Curl_cfree)(mem);
   }
 
-  if(source)
+  if(source && ptr)
     curl_dbg_log("MEM %s:%d free(%p)\n", source, line, (void *)ptr);
 }
 
diff --git a/lib/mime.c b/lib/mime.c
index b7273231..e13d92e9 100644
--- a/lib/mime.c
+++ b/lib/mime.c
@@ -1778,6 +1778,23 @@ const char *Curl_mime_contenttype(const char *filename)
   return NULL;
 }
 
+static bool content_type_match(const char *contenttype, const char *target)
+{
+  size_t len = strlen(target);
+
+  if(contenttype && strncasecompare(contenttype, target, len))
+    switch(contenttype[len]) {
+    case '\0':
+    case '\t':
+    case '\r':
+    case '\n':
+    case ' ':
+    case ';':
+      return TRUE;
+    }
+  return FALSE;
+}
+
 CURLcode Curl_mime_prepare_headers(curl_mimepart *part,
                                    const char *contenttype,
                                    const char *disposition,
@@ -1829,7 +1846,7 @@ CURLcode Curl_mime_prepare_headers(curl_mimepart *part,
       boundary = mime->boundary;
   }
   else if(contenttype && !customct &&
-          strcasecompare(contenttype, "text/plain"))
+          content_type_match(contenttype, "text/plain"))
     if(strategy == MIMESTRATEGY_MAIL || !part->filename)
       contenttype = NULL;
 
@@ -1905,7 +1922,7 @@ CURLcode Curl_mime_prepare_headers(curl_mimepart *part,
     curl_mimepart *subpart;
 
     disposition = NULL;
-    if(strcasecompare(contenttype, "multipart/form-data"))
+    if(content_type_match(contenttype, "multipart/form-data"))
       disposition = "form-data";
     for(subpart = mime->firstpart; subpart; subpart = subpart->nextpart) {
       ret = Curl_mime_prepare_headers(subpart, NULL, disposition, strategy);
diff --git a/lib/mk-ca-bundle.pl b/lib/mk-ca-bundle.pl
index 09e8e5b9..b9c7ed25 100755
--- a/lib/mk-ca-bundle.pl
+++ b/lib/mk-ca-bundle.pl
@@ -63,7 +63,7 @@ $opt_d = 'release';
 # If the OpenSSL commandline is not in search path you can configure it here!
 my $openssl = 'openssl';
 
-my $version = '1.27';
+my $version = '1.28';
 
 $opt_w = 76; # default base64 encoded lines length
 
@@ -531,6 +531,11 @@ while (<TXT>) {
     } else {
       my $data = $cka_value;
       $cka_value = "";
+
+      if(!length($data)) {
+          # if empty, skip
+          next;
+      }
       my $encoded = MIME::Base64::encode_base64($data, '');
       $encoded =~ s/(.{1,${opt_w}})/$1\n/g;
       my $pem = "-----BEGIN CERTIFICATE-----\n"
diff --git a/lib/mk-ca-bundle.vbs b/lib/mk-ca-bundle.vbs
index 8da27926..34871711 100755
--- a/lib/mk-ca-bundle.vbs
+++ b/lib/mk-ca-bundle.vbs
@@ -5,7 +5,7 @@
 '*                            | (__| |_| |  _ <| |___

 '*                             \___|\___/|_| \_\_____|

 '*

-'* Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.

+'* Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.

 '*

 '* This software is licensed as described in the file COPYING, which

 '* you should have received as part of this distribution. The terms

diff --git a/lib/mqtt.c b/lib/mqtt.c
new file mode 100644
index 00000000..43a3b6e5
--- /dev/null
+++ b/lib/mqtt.c
@@ -0,0 +1,627 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 2019, Björn Stenberg, <bjorn@haxx.se>
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+
+#include "curl_setup.h"
+
+#ifdef CURL_ENABLE_MQTT
+
+#include "urldata.h"
+#include <curl/curl.h>
+#include "transfer.h"
+#include "sendf.h"
+#include "progress.h"
+#include "mqtt.h"
+#include "select.h"
+#include "strdup.h"
+#include "url.h"
+#include "escape.h"
+#include "warnless.h"
+#include "curl_printf.h"
+#include "curl_memory.h"
+#include "multiif.h"
+#include "rand.h"
+
+/* The last #include file should be: */
+#include "memdebug.h"
+
+#define MQTT_MSG_CONNECT   0x10
+#define MQTT_MSG_CONNACK   0x20
+#define MQTT_MSG_PUBLISH   0x30
+#define MQTT_MSG_SUBSCRIBE 0x82
+#define MQTT_MSG_SUBACK    0x90
+#define MQTT_MSG_DISCONNECT 0xe0
+
+#define MQTT_CONNACK_LEN 2
+#define MQTT_SUBACK_LEN 3
+#define MQTT_CLIENTID_LEN 12 /* "curl0123abcd" */
+
+/*
+ * Forward declarations.
+ */
+
+static CURLcode mqtt_do(struct connectdata *conn, bool *done);
+static CURLcode mqtt_doing(struct connectdata *conn, bool *done);
+static int mqtt_getsock(struct connectdata *conn, curl_socket_t *sock);
+static CURLcode mqtt_setup_conn(struct connectdata *conn);
+
+/*
+ * MQTT protocol handler.
+ */
+
+const struct Curl_handler Curl_handler_mqtt = {
+  "MQTT",                             /* scheme */
+  mqtt_setup_conn,                    /* setup_connection */
+  mqtt_do,                            /* do_it */
+  ZERO_NULL,                          /* done */
+  ZERO_NULL,                          /* do_more */
+  ZERO_NULL,                          /* connect_it */
+  ZERO_NULL,                          /* connecting */
+  mqtt_doing,                         /* doing */
+  ZERO_NULL,                          /* proto_getsock */
+  mqtt_getsock,                       /* doing_getsock */
+  ZERO_NULL,                          /* domore_getsock */
+  ZERO_NULL,                          /* perform_getsock */
+  ZERO_NULL,                          /* disconnect */
+  ZERO_NULL,                          /* readwrite */
+  ZERO_NULL,                          /* connection_check */
+  PORT_MQTT,                          /* defport */
+  CURLPROTO_MQTT,                     /* protocol */
+  PROTOPT_NONE                        /* flags */
+};
+
+static CURLcode mqtt_setup_conn(struct connectdata *conn)
+{
+  /* allocate the HTTP-specific struct for the Curl_easy, only to survive
+     during this request */
+  struct MQTT *mq;
+  struct Curl_easy *data = conn->data;
+  DEBUGASSERT(data->req.protop == NULL);
+
+  mq = calloc(1, sizeof(struct MQTT));
+  if(!mq)
+    return CURLE_OUT_OF_MEMORY;
+  data->req.protop = mq;
+  return CURLE_OK;
+}
+
+static CURLcode mqtt_send(struct connectdata *conn,
+                          char *buf, size_t len)
+{
+  CURLcode result = CURLE_OK;
+  curl_socket_t sockfd = conn->sock[FIRSTSOCKET];
+  struct Curl_easy *data = conn->data;
+  struct MQTT *mq = data->req.protop;
+  ssize_t n;
+  result = Curl_write(conn, sockfd, buf, len, &n);
+  if(!result && data->set.verbose)
+    Curl_debug(data, CURLINFO_HEADER_OUT, buf, (size_t)n);
+  if(len != (size_t)n) {
+    size_t nsend = len - n;
+    char *sendleftovers = Curl_memdup(&buf[n], nsend);
+    if(!sendleftovers)
+      return CURLE_OUT_OF_MEMORY;
+    mq->sendleftovers = sendleftovers;
+    mq->nsend = nsend;
+  }
+  return result;
+}
+
+/* Generic function called by the multi interface to figure out what socket(s)
+   to wait for and for what actions during the DOING and PROTOCONNECT
+   states */
+static int mqtt_getsock(struct connectdata *conn,
+                        curl_socket_t *sock)
+{
+  sock[0] = conn->sock[FIRSTSOCKET];
+  return GETSOCK_READSOCK(FIRSTSOCKET);
+}
+
+static CURLcode mqtt_connect(struct connectdata *conn)
+{
+  CURLcode result = CURLE_OK;
+  const size_t client_id_offset = 14;
+  const size_t packetlen = client_id_offset + MQTT_CLIENTID_LEN;
+  char client_id[MQTT_CLIENTID_LEN + 1] = "curl";
+  const size_t curl_len = strlen("curl");
+  char packet[32] = {
+    MQTT_MSG_CONNECT,  /* packet type */
+    0x00,              /* remaining length */
+    0x00, 0x04,        /* protocol length */
+    'M','Q','T','T',   /* protocol name */
+    0x04,              /* protocol level */
+    0x02,              /* CONNECT flag: CleanSession */
+    0x00, 0x3c,        /* keep-alive 0 = disabled */
+    0x00, 0x00         /* payload1 length */
+  };
+  packet[1] = (packetlen - 2) & 0x7f;
+  packet[client_id_offset - 1] = MQTT_CLIENTID_LEN;
+
+  result = Curl_rand_hex(conn->data, (unsigned char *)&client_id[curl_len],
+                         MQTT_CLIENTID_LEN - curl_len + 1);
+  memcpy(&packet[client_id_offset], client_id, MQTT_CLIENTID_LEN);
+  infof(conn->data, "Using client id '%s'\n", client_id);
+  if(!result)
+    result = mqtt_send(conn, packet, packetlen);
+  return result;
+}
+
+static CURLcode mqtt_disconnect(struct connectdata *conn)
+{
+  CURLcode result = CURLE_OK;
+  result = mqtt_send(conn, (char *)"\xe0\x00", 2);
+  return result;
+}
+
+static CURLcode mqtt_verify_connack(struct connectdata *conn)
+{
+  CURLcode result;
+  curl_socket_t sockfd = conn->sock[FIRSTSOCKET];
+  unsigned char readbuf[MQTT_CONNACK_LEN];
+  ssize_t nread;
+  struct Curl_easy *data = conn->data;
+
+  result = Curl_read(conn, sockfd, (char *)readbuf, MQTT_CONNACK_LEN, &nread);
+  if(result)
+    goto fail;
+
+  if(data->set.verbose)
+    Curl_debug(data, CURLINFO_HEADER_IN, (char *)readbuf, (size_t)nread);
+
+  /* fixme */
+  if(nread < MQTT_CONNACK_LEN) {
+    result = CURLE_WEIRD_SERVER_REPLY;
+    goto fail;
+  }
+
+  /* verify CONNACK */
+  if(readbuf[0] != 0x00 || readbuf[1] != 0x00) {
+    failf(data, "Expected %02x%02x but got %02x%02x",
+          0x00, 0x00, readbuf[0], readbuf[1]);
+    result = CURLE_WEIRD_SERVER_REPLY;
+  }
+
+fail:
+  return result;
+}
+
+static CURLcode mqtt_get_topic(struct connectdata *conn,
+                               char **topic, size_t *topiclen)
+{
+  CURLcode result = CURLE_OK;
+  char *path = conn->data->state.up.path;
+
+  if(strlen(path) > 1) {
+    result = Curl_urldecode(conn->data, path + 1, 0, topic, topiclen, FALSE);
+  }
+  else {
+    failf(conn->data, "Error: No topic specified.");
+    result = CURLE_URL_MALFORMAT;
+  }
+  return result;
+}
+
+
+static int mqtt_encode_len(char *buf, size_t len)
+{
+  unsigned char encoded;
+  int i;
+
+  for(i = 0; (len > 0) && (i<4); i++) {
+    encoded = len % 0x80;
+    len /= 0x80;
+    if(len)
+      encoded |= 0x80;
+    buf[i] = encoded;
+  }
+
+  return i;
+}
+
+static CURLcode mqtt_subscribe(struct connectdata *conn)
+{
+  CURLcode result = CURLE_OK;
+  char *topic = NULL;
+  size_t topiclen;
+  unsigned char *packet = NULL;
+  size_t packetlen;
+  char encodedsize[4];
+  size_t n;
+
+  result = mqtt_get_topic(conn, &topic, &topiclen);
+  if(result)
+    goto fail;
+
+  conn->proto.mqtt.packetid++;
+
+  packetlen = topiclen + 5; /* packetid + topic (has a two byte length field)
+                               + 2 bytes topic length + QoS byte */
+  n = mqtt_encode_len((char *)encodedsize, packetlen);
+  packetlen += n + 1; /* add one for the control packet type byte */
+
+  packet = malloc(packetlen);
+  if(!packet) {
+    result = CURLE_OUT_OF_MEMORY;
+    goto fail;
+  }
+
+  packet[0] = MQTT_MSG_SUBSCRIBE;
+  memcpy(&packet[1], encodedsize, n);
+  packet[1 + n] = (conn->proto.mqtt.packetid >> 8) & 0xff;
+  packet[2 + n] = conn->proto.mqtt.packetid & 0xff;
+  packet[3 + n] = (topiclen >> 8) & 0xff;
+  packet[4 + n ] = topiclen & 0xff;
+  memcpy(&packet[5 + n], topic, topiclen);
+  packet[5 + n + topiclen] = 0; /* QoS zero */
+
+  result = mqtt_send(conn, (char *)packet, packetlen);
+
+fail:
+  free(topic);
+  free(packet);
+  return result;
+}
+
+/*
+ * Called when the first byte was already read.
+ */
+static CURLcode mqtt_verify_suback(struct connectdata *conn)
+{
+  CURLcode result;
+  curl_socket_t sockfd = conn->sock[FIRSTSOCKET];
+  unsigned char readbuf[MQTT_SUBACK_LEN];
+  ssize_t nread;
+  struct mqtt_conn *mqtt = &conn->proto.mqtt;
+
+  result = Curl_read(conn, sockfd, (char *)readbuf, MQTT_SUBACK_LEN, &nread);
+  if(result)
+    goto fail;
+
+  if(conn->data->set.verbose)
+    Curl_debug(conn->data, CURLINFO_HEADER_IN, (char *)readbuf, (size_t)nread);
+
+  /* fixme */
+  if(nread < MQTT_SUBACK_LEN) {
+    result = CURLE_WEIRD_SERVER_REPLY;
+    goto fail;
+  }
+
+  /* verify SUBACK */
+  if(readbuf[0] != ((mqtt->packetid >> 8) & 0xff) ||
+     readbuf[1] != (mqtt->packetid & 0xff) ||
+     readbuf[2] != 0x00)
+    result = CURLE_WEIRD_SERVER_REPLY;
+
+fail:
+  return result;
+}
+
+static CURLcode mqtt_publish(struct connectdata *conn)
+{
+  CURLcode result;
+  char *payload = conn->data->set.postfields;
+  size_t payloadlen = (size_t)conn->data->set.postfieldsize;
+  char *topic = NULL;
+  size_t topiclen;
+  unsigned char *pkt = NULL;
+  size_t i = 0;
+  size_t remaininglength;
+  size_t encodelen;
+  char encodedbytes[4];
+
+  result = mqtt_get_topic(conn, &topic, &topiclen);
+  if(result)
+    goto fail;
+
+  remaininglength = payloadlen + 2 + topiclen;
+  encodelen = mqtt_encode_len(encodedbytes, remaininglength);
+
+  /* add the control byte and the encoded remaining length */
+  pkt = malloc(remaininglength + 1 + encodelen);
+  if(!pkt) {
+    result = CURLE_OUT_OF_MEMORY;
+    goto fail;
+  }
+
+  /* assemble packet */
+  pkt[i++] = MQTT_MSG_PUBLISH;
+  memcpy(&pkt[i], encodedbytes, encodelen);
+  i += encodelen;
+  pkt[i++] = (topiclen >> 8) & 0xff;
+  pkt[i++] = (topiclen & 0xff);
+  memcpy(&pkt[i], topic, topiclen);
+  i += topiclen;
+  memcpy(&pkt[i], payload, payloadlen);
+  i += payloadlen;
+  result = mqtt_send(conn, (char *)pkt, i);
+
+fail:
+  free(pkt);
+  free(topic);
+  return result;
+}
+
+static size_t mqtt_decode_len(unsigned char *buf,
+                              size_t buflen, size_t *lenbytes)
+{
+  size_t len = 0;
+  size_t mult = 1;
+  size_t i;
+  unsigned char encoded = 128;
+
+  for(i = 0; (i < buflen) && (encoded & 128); i++) {
+    encoded = buf[i];
+    len += (encoded & 127) * mult;
+    mult *= 128;
+  }
+
+  if(lenbytes)
+    *lenbytes = i;
+
+  return len;
+}
+
+#ifdef CURLDEBUG
+static const char *statenames[]={
+  "MQTT_FIRST",
+  "MQTT_REMAINING_LENGTH",
+  "MQTT_CONNACK",
+  "MQTT_SUBACK",
+  "MQTT_SUBACK_COMING",
+  "MQTT_PUBWAIT",
+  "MQTT_PUB_REMAIN",
+
+  "NOT A STATE"
+};
+#endif
+
+/* The only way to change state */
+static void mqstate(struct connectdata *conn,
+                    enum mqttstate state,
+                    enum mqttstate nextstate) /* used if state == FIRST */
+{
+  struct mqtt_conn *mqtt = &conn->proto.mqtt;
+#ifdef CURLDEBUG
+  infof(conn->data, "%s (from %s) (next is %s)\n",
+        statenames[state],
+        statenames[mqtt->state],
+        (state == MQTT_FIRST)? statenames[nextstate] : "");
+#endif
+  mqtt->state = state;
+  if(state == MQTT_FIRST)
+    mqtt->nextstate = nextstate;
+}
+
+
+/* for the publish packet */
+#define MQTT_HEADER_LEN 5    /* max 5 bytes */
+
+static CURLcode mqtt_read_publish(struct connectdata *conn,
+                                  bool *done)
+{
+  CURLcode result = CURLE_OK;
+  curl_socket_t sockfd = conn->sock[FIRSTSOCKET];
+  ssize_t nread;
+  struct Curl_easy *data = conn->data;
+  unsigned char *pkt = (unsigned char *)data->state.buffer;
+  size_t remlen;
+  struct mqtt_conn *mqtt = &conn->proto.mqtt;
+  struct MQTT *mq = data->req.protop;
+  unsigned char packet;
+
+  switch(mqtt->state) {
+  MQTT_SUBACK_COMING:
+  case MQTT_SUBACK_COMING:
+    result = mqtt_verify_suback(conn);
+    if(result)
+      break;
+
+    mqstate(conn, MQTT_FIRST, MQTT_PUBWAIT);
+    break;
+
+  case MQTT_SUBACK:
+  case MQTT_PUBWAIT:
+    /* we are expecting PUBLISH or SUBACK */
+    packet = mq->firstbyte & 0xf0;
+    if(packet == MQTT_MSG_PUBLISH)
+      mqstate(conn, MQTT_PUB_REMAIN, MQTT_NOSTATE);
+    else if(packet == MQTT_MSG_SUBACK) {
+      mqstate(conn, MQTT_SUBACK_COMING, MQTT_NOSTATE);
+      goto MQTT_SUBACK_COMING;
+    }
+    else if(packet == MQTT_MSG_DISCONNECT) {
+      infof(data, "Got DISCONNECT\n");
+      *done = TRUE;
+      goto end;
+    }
+    else {
+      result = CURLE_WEIRD_SERVER_REPLY;
+      goto end;
+    }
+
+    /* -- switched state -- */
+    remlen = mq->remaining_length;
+    infof(data, "Remaining length: %zd bytes\n", remlen);
+    Curl_pgrsSetDownloadSize(data, remlen);
+    data->req.bytecount = 0;
+    data->req.size = remlen;
+    mq->npacket = remlen; /* get this many bytes */
+    /* FALLTHROUGH */
+  case MQTT_PUB_REMAIN: {
+    /* read rest of packet, but no more. Cap to buffer size */
+    struct SingleRequest *k = &data->req;
+    size_t rest = mq->npacket;
+    if(rest > (size_t)data->set.buffer_size)
+      rest = (size_t)data->set.buffer_size;
+    result = Curl_read(conn, sockfd, (char *)pkt, rest, &nread);
+    if(result) {
+      if(CURLE_AGAIN == result) {
+        infof(data, "EEEE AAAAGAIN\n");
+      }
+      goto end;
+    }
+    if(!nread) {
+      infof(data, "server disconnected\n");
+      result = CURLE_PARTIAL_FILE;
+      goto end;
+    }
+    if(data->set.verbose)
+      Curl_debug(data, CURLINFO_DATA_IN, (char *)pkt, (size_t)nread);
+
+    mq->npacket -= nread;
+    k->bytecount += nread;
+    Curl_pgrsSetDownloadCounter(data, k->bytecount);
+
+    /* if QoS is set, message contains packet id */
+
+    result = Curl_client_write(conn, CLIENTWRITE_BODY, (char *)pkt, nread);
+    if(result)
+      goto end;
+
+    if(!mq->npacket)
+      /* no more PUBLISH payload, back to subscribe wait state */
+      mqstate(conn, MQTT_FIRST, MQTT_PUBWAIT);
+    break;
+  }
+  default:
+    DEBUGASSERT(NULL); /* illegal state */
+    result = CURLE_WEIRD_SERVER_REPLY;
+    goto end;
+  }
+  end:
+  return result;
+}
+
+static CURLcode mqtt_do(struct connectdata *conn, bool *done)
+{
+  CURLcode result = CURLE_OK;
+  struct Curl_easy *data = conn->data;
+
+  *done = FALSE; /* unconditionally */
+
+  result = mqtt_connect(conn);
+  if(result) {
+    failf(data, "Error %d sending MQTT CONN request", result);
+    return result;
+  }
+  mqstate(conn, MQTT_FIRST, MQTT_CONNACK);
+  return CURLE_OK;
+}
+
+static CURLcode mqtt_doing(struct connectdata *conn, bool *done)
+{
+  CURLcode result = CURLE_OK;
+  struct mqtt_conn *mqtt = &conn->proto.mqtt;
+  struct Curl_easy *data = conn->data;
+  struct MQTT *mq = data->req.protop;
+  ssize_t nread;
+  curl_socket_t sockfd = conn->sock[FIRSTSOCKET];
+  unsigned char *pkt = (unsigned char *)data->state.buffer;
+  unsigned char byte;
+
+  *done = FALSE;
+
+  if(mq->nsend) {
+    /* send the remainder of an outgoing packet */
+    char *ptr = mq->sendleftovers;
+    result = mqtt_send(conn, mq->sendleftovers, mq->nsend);
+    free(ptr);
+    if(result)
+      return result;
+  }
+
+  infof(data, "mqtt_doing: state [%d]\n", (int) mqtt->state);
+  switch(mqtt->state) {
+  case MQTT_FIRST:
+    /* Read the initial byte only */
+    result = Curl_read(conn, sockfd, (char *)&mq->firstbyte, 1, &nread);
+    if(result)
+      break;
+    if(data->set.verbose)
+      Curl_debug(data, CURLINFO_HEADER_IN, (char *)&mq->firstbyte, 1);
+    /* remember the first byte */
+    mq->npacket = 0;
+    mqstate(conn, MQTT_REMAINING_LENGTH, MQTT_NOSTATE);
+    /* FALLTHROUGH */
+  case MQTT_REMAINING_LENGTH:
+    do {
+      result = Curl_read(conn, sockfd, (char *)&byte, 1, &nread);
+      if(result)
+        break;
+      if(data->set.verbose)
+        Curl_debug(data, CURLINFO_HEADER_IN, (char *)&byte, 1);
+      pkt[mq->npacket++] = byte;
+    } while((byte & 0x80) && (mq->npacket < 4));
+    if(result)
+      break;
+    mq->remaining_length = mqtt_decode_len(&pkt[0], mq->npacket, NULL);
+    mq->npacket = 0;
+    if(mq->remaining_length) {
+      mqstate(conn, mqtt->nextstate, MQTT_NOSTATE);
+      break;
+    }
+    mqstate(conn, MQTT_FIRST, MQTT_FIRST);
+
+    if(mq->firstbyte == MQTT_MSG_DISCONNECT) {
+      infof(data, "Got DISCONNECT\n");
+      *done = TRUE;
+    }
+    break;
+  case MQTT_CONNACK:
+    result = mqtt_verify_connack(conn);
+    if(result)
+      break;
+
+    if(conn->data->set.httpreq == HTTPREQ_POST) {
+      result = mqtt_publish(conn);
+      if(!result) {
+        result = mqtt_disconnect(conn);
+        *done = TRUE;
+      }
+      mqtt->nextstate = MQTT_FIRST;
+    }
+    else {
+      result = mqtt_subscribe(conn);
+      if(!result) {
+        mqstate(conn, MQTT_FIRST, MQTT_SUBACK);
+      }
+    }
+    break;
+
+  case MQTT_SUBACK:
+  case MQTT_PUBWAIT:
+  case MQTT_PUB_REMAIN:
+    result = mqtt_read_publish(conn, done);
+    break;
+
+  default:
+    failf(conn->data, "State not handled yet");
+    *done = TRUE;
+    break;
+  }
+
+  if(result == CURLE_AGAIN)
+    result = CURLE_OK;
+  return result;
+}
+
+#endif /* CURL_ENABLE_MQTT */
diff --git a/lib/mqtt.h b/lib/mqtt.h
new file mode 100644
index 00000000..37463d58
--- /dev/null
+++ b/lib/mqtt.h
@@ -0,0 +1,59 @@
+#ifndef HEADER_CURL_MQTT_H
+#define HEADER_CURL_MQTT_H
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 2019 - 2020, Björn Stenberg, <bjorn@haxx.se>
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+
+#ifdef CURL_ENABLE_MQTT
+extern const struct Curl_handler Curl_handler_mqtt;
+#endif
+
+enum mqttstate {
+  MQTT_FIRST,             /* 0 */
+  MQTT_REMAINING_LENGTH,  /* 1 */
+  MQTT_CONNACK,           /* 2 */
+  MQTT_SUBACK,            /* 3 */
+  MQTT_SUBACK_COMING,     /* 4 - the SUBACK remainder */
+  MQTT_PUBWAIT,    /* 5 - wait for publish */
+  MQTT_PUB_REMAIN,  /* 6 - wait for the remainder of the publish */
+
+  MQTT_NOSTATE /* 7 - never used an actual state */
+};
+
+struct mqtt_conn {
+  enum mqttstate state;
+  enum mqttstate nextstate; /* switch to this after remaining length is
+                               done */
+  unsigned int packetid;
+};
+
+/* protocol-specific transfer-related data */
+struct MQTT {
+  char *sendleftovers;
+  size_t nsend; /* size of sendleftovers */
+
+  /* when receiving */
+  size_t npacket; /* byte counter */
+  unsigned char firstbyte;
+  size_t remaining_length;
+};
+
+#endif /* HEADER_CURL_MQTT_H */
diff --git a/lib/multi.c b/lib/multi.c
index e10e7529..d4f03187 100644
--- a/lib/multi.c
+++ b/lib/multi.c
@@ -700,6 +700,10 @@ CURLMcode curl_multi_remove_handle(struct Curl_multi *multi,
   if(!data->multi)
     return CURLM_OK; /* it is already removed so let's say it is fine! */
 
+  /* Prevent users from trying to remove an easy handle from the wrong multi */
+  if(data->multi != multi)
+    return CURLM_BAD_EASY_HANDLE;
+
   if(multi->in_callback)
     return CURLM_RECURSIVE_API_CALL;
 
diff --git a/lib/select.c b/lib/select.c
index b372efff..d91b20a4 100644
--- a/lib/select.c
+++ b/lib/select.c
@@ -24,6 +24,8 @@
 
 #ifdef HAVE_SYS_SELECT_H
 #include <sys/select.h>
+#elif defined(HAVE_UNISTD_H)
+#include <unistd.h>
 #endif
 
 #if !defined(HAVE_SELECT) && !defined(HAVE_POLL_FINE)
@@ -101,6 +103,82 @@ int Curl_wait_ms(int timeout_ms)
 }
 
 /*
+ * This is a wrapper around select() to aid in Windows compatibility.
+ * A negative timeout value makes this function wait indefinitely,
+ * unless no valid file descriptor is given, when this happens the
+ * negative timeout is ignored and the function times out immediately.
+ *
+ * Return values:
+ *   -1 = system call error or fd >= FD_SETSIZE
+ *    0 = timeout
+ *    N = number of signalled file descriptors
+ */
+int Curl_select(curl_socket_t maxfd,
+                fd_set *fds_read,
+                fd_set *fds_write,
+                fd_set *fds_err,
+                time_t timeout_ms)     /* milliseconds to wait */
+{
+  struct timeval pending_tv;
+  struct timeval *ptimeout;
+  int pending_ms;
+  int r;
+
+#if SIZEOF_TIME_T != SIZEOF_INT
+  /* wrap-around precaution */
+  if(timeout_ms >= INT_MAX)
+    timeout_ms = INT_MAX;
+#endif
+
+#ifdef USE_WINSOCK
+  /* WinSock select() can't handle zero events.  See the comment below. */
+  if((!fds_read || fds_read->fd_count == 0) &&
+     (!fds_write || fds_write->fd_count == 0) &&
+     (!fds_err || fds_err->fd_count == 0)) {
+    r = Curl_wait_ms((int)timeout_ms);
+    return r;
+  }
+#endif
+
+  ptimeout = &pending_tv;
+
+  if(timeout_ms < 0) {
+    ptimeout = NULL;
+  }
+  else if(timeout_ms > 0) {
+    pending_ms = (int)timeout_ms;
+    pending_tv.tv_sec = pending_ms / 1000;
+    pending_tv.tv_usec = (pending_ms % 1000) * 1000;
+  }
+  else if(!timeout_ms) {
+    pending_tv.tv_sec = 0;
+    pending_tv.tv_usec = 0;
+  }
+
+#ifdef USE_WINSOCK
+  /* WinSock select() must not be called with an fd_set that contains zero
+    fd flags, or it will return WSAEINVAL.  But, it also can't be called
+    with no fd_sets at all!  From the documentation:
+
+    Any two of the parameters, readfds, writefds, or exceptfds, can be
+    given as null. At least one must be non-null, and any non-null
+    descriptor set must contain at least one handle to a socket.
+
+    It is unclear why WinSock doesn't just handle this for us instead of
+    calling this an error.
+  */
+  r = select((int)maxfd + 1,
+             fds_read && fds_read->fd_count ? fds_read : NULL,
+             fds_write && fds_write->fd_count ? fds_write : NULL,
+             fds_err && fds_err->fd_count ? fds_err : NULL, ptimeout);
+#else
+  r = select((int)maxfd + 1, fds_read, fds_write, fds_err, ptimeout);
+#endif
+
+  return r;
+}
+
+/*
  * Wait for read or write events on a set of file descriptors. It uses poll()
  * when a fine poll() is available, in order to avoid limits with FD_SETSIZE,
  * otherwise select() is used.  An error is returned if select() is being used
@@ -123,20 +201,18 @@ int Curl_wait_ms(int timeout_ms)
 int Curl_socket_check(curl_socket_t readfd0, /* two sockets to read from */
                       curl_socket_t readfd1,
                       curl_socket_t writefd, /* socket to write to */
-                      time_t timeout_ms)     /* milliseconds to wait */
+                      timediff_t timeout_ms)     /* milliseconds to wait */
 {
 #ifdef HAVE_POLL_FINE
   struct pollfd pfd[3];
+  int pending_ms;
   int num;
 #else
-  struct timeval pending_tv;
-  struct timeval *ptimeout;
   fd_set fds_read;
   fd_set fds_write;
   fd_set fds_err;
   curl_socket_t maxfd;
 #endif
-  int pending_ms = 0;
   int r;
   int ret;
 
@@ -158,10 +234,6 @@ int Curl_socket_check(curl_socket_t readfd0, /* two sockets to read from */
      when function is called with a zero timeout or a negative timeout
      value indicating a blocking call should be performed. */
 
-  if(timeout_ms > 0) {
-    pending_ms = (int)timeout_ms;
-  }
-
 #ifdef HAVE_POLL_FINE
 
   num = 0;
@@ -184,9 +256,11 @@ int Curl_socket_check(curl_socket_t readfd0, /* two sockets to read from */
     num++;
   }
 
-  if(timeout_ms < 0)
+  if(timeout_ms > 0)
+    pending_ms = (int)timeout_ms;
+  else if(timeout_ms < 0)
     pending_ms = -1;
-  else if(!timeout_ms)
+  else
     pending_ms = 0;
   r = poll(pfd, num, pending_ms);
 
@@ -249,46 +323,17 @@ int Curl_socket_check(curl_socket_t readfd0, /* two sockets to read from */
       maxfd = writefd;
   }
 
-  ptimeout = (timeout_ms < 0) ? NULL : &pending_tv;
-
-  if(timeout_ms > 0) {
-    pending_tv.tv_sec = pending_ms / 1000;
-    pending_tv.tv_usec = (pending_ms % 1000) * 1000;
-  }
-  else if(!timeout_ms) {
-    pending_tv.tv_sec = 0;
-    pending_tv.tv_usec = 0;
-  }
-
-  /* WinSock select() must not be called with an fd_set that contains zero
-     fd flags, or it will return WSAEINVAL.  But, it also can't be called
-     with no fd_sets at all!  From the documentation:
-
-     Any two of the parameters, readfds, writefds, or exceptfds, can be
-     given as null. At least one must be non-null, and any non-null
-     descriptor set must contain at least one handle to a socket.
-
-     We know that we have at least one bit set in at least two fd_sets in
+  /* We know that we have at least one bit set in at least two fd_sets in
      this case, but we may have no bits set in either fds_read or fd_write,
      so check for that and handle it.  Luckily, with WinSock, we can _also_
      ask how many bits are set on an fd_set.
 
-     It is unclear why WinSock doesn't just handle this for us instead of
-     calling this an error.
-
      Note also that WinSock ignores the first argument, so we don't worry
      about the fact that maxfd is computed incorrectly with WinSock (since
      curl_socket_t is unsigned in such cases and thus -1 is the largest
      value).
   */
-#ifdef USE_WINSOCK
-  r = select((int)maxfd + 1,
-             fds_read.fd_count ? &fds_read : NULL,
-             fds_write.fd_count ? &fds_write : NULL,
-             &fds_err, ptimeout);
-#else
-  r = select((int)maxfd + 1, &fds_read, &fds_write, &fds_err, ptimeout);
-#endif
+  r = Curl_select(maxfd, &fds_read, &fds_write, &fds_err, (time_t)timeout_ms);
 
   if(r < 0)
     return -1;
@@ -336,9 +381,9 @@ int Curl_socket_check(curl_socket_t readfd0, /* two sockets to read from */
  */
 int Curl_poll(struct pollfd ufds[], unsigned int nfds, int timeout_ms)
 {
-#ifndef HAVE_POLL_FINE
-  struct timeval pending_tv;
-  struct timeval *ptimeout;
+#ifdef HAVE_POLL_FINE
+  int pending_ms;
+#else
   fd_set fds_read;
   fd_set fds_write;
   fd_set fds_err;
@@ -346,7 +391,6 @@ int Curl_poll(struct pollfd ufds[], unsigned int nfds, int timeout_ms)
 #endif
   bool fds_none = TRUE;
   unsigned int i;
-  int pending_ms = 0;
   int r;
 
   if(ufds) {
@@ -367,15 +411,13 @@ int Curl_poll(struct pollfd ufds[], unsigned int nfds, int timeout_ms)
      when function is called with a zero timeout or a negative timeout
      value indicating a blocking call should be performed. */
 
-  if(timeout_ms > 0) {
-    pending_ms = timeout_ms;
-  }
-
 #ifdef HAVE_POLL_FINE
 
-  if(timeout_ms < 0)
+  if(timeout_ms > 0)
+    pending_ms = timeout_ms;
+  else if(timeout_ms < 0)
     pending_ms = -1;
-  else if(!timeout_ms)
+  else
     pending_ms = 0;
   r = poll(ufds, nfds, pending_ms);
 
@@ -418,39 +460,7 @@ int Curl_poll(struct pollfd ufds[], unsigned int nfds, int timeout_ms)
     }
   }
 
-#ifdef USE_WINSOCK
-  /* WinSock select() can't handle zero events.  See the comment about this in
-     Curl_check_socket(). */
-  if(fds_read.fd_count == 0 && fds_write.fd_count == 0
-     && fds_err.fd_count == 0) {
-    r = Curl_wait_ms(timeout_ms);
-    return r;
-  }
-#endif
-
-  ptimeout = (timeout_ms < 0) ? NULL : &pending_tv;
-
-  if(timeout_ms > 0) {
-    pending_tv.tv_sec = pending_ms / 1000;
-    pending_tv.tv_usec = (pending_ms % 1000) * 1000;
-  }
-  else if(!timeout_ms) {
-    pending_tv.tv_sec = 0;
-    pending_tv.tv_usec = 0;
-  }
-
-#ifdef USE_WINSOCK
-  r = select((int)maxfd + 1,
-             /* WinSock select() can't handle fd_sets with zero bits set, so
-                don't give it such arguments.  See the comment about this in
-                Curl_check_socket().
-             */
-             fds_read.fd_count ? &fds_read : NULL,
-             fds_write.fd_count ? &fds_write : NULL,
-             fds_err.fd_count ? &fds_err : NULL, ptimeout);
-#else
-  r = select((int)maxfd + 1, &fds_read, &fds_write, &fds_err, ptimeout);
-#endif
+  r = Curl_select(maxfd, &fds_read, &fds_write, &fds_err, timeout_ms);
 
   if(r < 0)
     return -1;
diff --git a/lib/select.h b/lib/select.h
index ec3021aa..0fd8ed51 100644
--- a/lib/select.h
+++ b/lib/select.h
@@ -72,13 +72,19 @@ struct pollfd
    therefore defined here */
 #define CURL_CSELECT_IN2 (CURL_CSELECT_ERR << 1)
 
+int Curl_select(curl_socket_t maxfd,
+                fd_set *fds_read,
+                fd_set *fds_write,
+                fd_set *fds_err,
+                time_t timeout_ms);
+
 int Curl_socket_check(curl_socket_t readfd, curl_socket_t readfd2,
                       curl_socket_t writefd,
-                      time_t timeout_ms);
+                      timediff_t timeout_ms);
 #define SOCKET_READABLE(x,z) \
-  Curl_socket_check(x, CURL_SOCKET_BAD, CURL_SOCKET_BAD, (time_t)z)
+  Curl_socket_check(x, CURL_SOCKET_BAD, CURL_SOCKET_BAD, z)
 #define SOCKET_WRITABLE(x,z) \
-  Curl_socket_check(CURL_SOCKET_BAD, CURL_SOCKET_BAD, x, (time_t)z)
+  Curl_socket_check(CURL_SOCKET_BAD, CURL_SOCKET_BAD, x, z)
 
 int Curl_poll(struct pollfd ufds[], unsigned int nfds, int timeout_ms);
 int Curl_wait_ms(int timeout_ms);
diff --git a/lib/setopt.c b/lib/setopt.c
index 4648c872..04785a68 100644
--- a/lib/setopt.c
+++ b/lib/setopt.c
@@ -2134,6 +2134,7 @@ CURLcode Curl_vsetopt(struct Curl_easy *data, CURLoption option, va_list param)
       (bool)((arg&CURLSSLOPT_ALLOW_BEAST) ? TRUE : FALSE);
     data->set.ssl.no_revoke = !!(arg & CURLSSLOPT_NO_REVOKE);
     data->set.ssl.no_partialchain = !!(arg & CURLSSLOPT_NO_PARTIALCHAIN);
+    data->set.ssl.revoke_best_effort = !!(arg & CURLSSLOPT_REVOKE_BEST_EFFORT);
     break;
 
 #ifndef CURL_DISABLE_PROXY
@@ -2143,6 +2144,8 @@ CURLcode Curl_vsetopt(struct Curl_easy *data, CURLoption option, va_list param)
       (bool)((arg&CURLSSLOPT_ALLOW_BEAST) ? TRUE : FALSE);
     data->set.proxy_ssl.no_revoke = !!(arg & CURLSSLOPT_NO_REVOKE);
     data->set.proxy_ssl.no_partialchain = !!(arg & CURLSSLOPT_NO_PARTIALCHAIN);
+    data->set.proxy_ssl.revoke_best_effort =
+      !!(arg & CURLSSLOPT_REVOKE_BEST_EFFORT);
     break;
 #endif
 
diff --git a/lib/setup-win32.h b/lib/setup-win32.h
new file mode 100644
index 00000000..45b58476
--- /dev/null
+++ b/lib/setup-win32.h
@@ -0,0 +1,123 @@
+#ifndef HEADER_CURL_SETUP_WIN32_H
+#define HEADER_CURL_SETUP_WIN32_H
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+
+/*
+ * Include header files for windows builds before redefining anything.
+ * Use this preprocessor block only to include or exclude windows.h,
+ * winsock2.h, ws2tcpip.h or winsock.h. Any other windows thing belongs
+ * to any other further and independent block.  Under Cygwin things work
+ * just as under linux (e.g. <sys/socket.h>) and the winsock headers should
+ * never be included when __CYGWIN__ is defined.  configure script takes
+ * care of this, not defining HAVE_WINDOWS_H, HAVE_WINSOCK_H, HAVE_WINSOCK2_H,
+ * neither HAVE_WS2TCPIP_H when __CYGWIN__ is defined.
+ */
+
+#ifdef HAVE_WINDOWS_H
+#  if defined(UNICODE) && !defined(_UNICODE)
+#    define _UNICODE
+#  endif
+#  if defined(_UNICODE) && !defined(UNICODE)
+#    define UNICODE
+#  endif
+#  include <winerror.h>
+#  include <windows.h>
+#  ifdef HAVE_WINSOCK2_H
+#    include <winsock2.h>
+#    ifdef HAVE_WS2TCPIP_H
+#      include <ws2tcpip.h>
+#    endif
+#  else
+#    ifdef HAVE_WINSOCK_H
+#      include <winsock.h>
+#    endif
+#  endif
+#  include <tchar.h>
+#  ifdef UNICODE
+     typedef wchar_t *(*curl_wcsdup_callback)(const wchar_t *str);
+#  endif
+#endif
+
+/*
+ * Define USE_WINSOCK to 2 if we have and use WINSOCK2 API, else
+ * define USE_WINSOCK to 1 if we have and use WINSOCK  API, else
+ * undefine USE_WINSOCK.
+ */
+
+#undef USE_WINSOCK
+
+#ifdef HAVE_WINSOCK2_H
+#  define USE_WINSOCK 2
+#else
+#  ifdef HAVE_WINSOCK_H
+#    define USE_WINSOCK 1
+#  endif
+#endif
+
+/*
+ * Define _WIN32_WINNT_[OS] symbols because not all Windows build systems have
+ * those symbols to compare against, and even those that do may be missing
+ * newer symbols.
+ */
+
+#ifndef _WIN32_WINNT_NT4
+#define _WIN32_WINNT_NT4            0x0400   /* Windows NT 4.0 */
+#endif
+#ifndef _WIN32_WINNT_WIN2K
+#define _WIN32_WINNT_WIN2K          0x0500   /* Windows 2000 */
+#endif
+#ifndef _WIN32_WINNT_WINXP
+#define _WIN32_WINNT_WINXP          0x0501   /* Windows XP */
+#endif
+#ifndef _WIN32_WINNT_WS03
+#define _WIN32_WINNT_WS03           0x0502   /* Windows Server 2003 */
+#endif
+#ifndef _WIN32_WINNT_WIN6
+#define _WIN32_WINNT_WIN6           0x0600   /* Windows Vista */
+#endif
+#ifndef _WIN32_WINNT_VISTA
+#define _WIN32_WINNT_VISTA          0x0600   /* Windows Vista */
+#endif
+#ifndef _WIN32_WINNT_WS08
+#define _WIN32_WINNT_WS08           0x0600   /* Windows Server 2008 */
+#endif
+#ifndef _WIN32_WINNT_LONGHORN
+#define _WIN32_WINNT_LONGHORN       0x0600   /* Windows Vista */
+#endif
+#ifndef _WIN32_WINNT_WIN7
+#define _WIN32_WINNT_WIN7           0x0601   /* Windows 7 */
+#endif
+#ifndef _WIN32_WINNT_WIN8
+#define _WIN32_WINNT_WIN8           0x0602   /* Windows 8 */
+#endif
+#ifndef _WIN32_WINNT_WINBLUE
+#define _WIN32_WINNT_WINBLUE        0x0603   /* Windows 8.1 */
+#endif
+#ifndef _WIN32_WINNT_WINTHRESHOLD
+#define _WIN32_WINNT_WINTHRESHOLD   0x0A00   /* Windows 10 */
+#endif
+#ifndef _WIN32_WINNT_WIN10
+#define _WIN32_WINNT_WIN10          0x0A00   /* Windows 10 */
+#endif
+
+#endif /* HEADER_CURL_SETUP_WIN32_H */
diff --git a/lib/sha256.c b/lib/sha256.c
index 352d577e..00d98ce4 100644
--- a/lib/sha256.c
+++ b/lib/sha256.c
@@ -207,8 +207,8 @@ typedef struct {
 
 static void SHA256_Init(SHA256_CTX *ctx)
 {
-  if(CryptAcquireContext(&ctx->hCryptProv, NULL, NULL,
-                         PROV_RSA_AES, CRYPT_VERIFYCONTEXT)) {
+  if(CryptAcquireContext(&ctx->hCryptProv, NULL, NULL, PROV_RSA_AES,
+                         CRYPT_VERIFYCONTEXT | CRYPT_SILENT)) {
     CryptCreateHash(ctx->hCryptProv, CALG_SHA_256, 0, 0, &ctx->hHash);
   }
 }
diff --git a/lib/smb.h b/lib/smb.h
index 9ce6b561..136a89ce 100644
--- a/lib/smb.h
+++ b/lib/smb.h
@@ -8,7 +8,7 @@
  *                             \___|\___/|_| \_\_____|
  *
  * Copyright (C) 2014, Bill Nagel <wnagel@tycoint.com>, Exacq Technologies
- * Copyright (C) 2018, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 2018 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -193,7 +193,6 @@ struct smb_nt_create_response {
   unsigned int ext_file_attributes;
   curl_off_t allocation_size;
   curl_off_t end_of_file;
-
 } PACK;
 
 struct smb_read {
diff --git a/lib/smtp.c b/lib/smtp.c
index e1872871..bf65f246 100644
--- a/lib/smtp.c
+++ b/lib/smtp.c
@@ -625,8 +625,7 @@ static CURLcode smtp_perform_mail(struct connectdata *conn)
         utf8 = TRUE;
 
       if(host.name) {
-        free(from);
-        from = aprintf("<%s@%s>", address, host.name);
+        auth = aprintf("<%s@%s>", address, host.name);
 
         Curl_free_idnconverted_hostname(&host);
       }
@@ -636,8 +635,6 @@ static CURLcode smtp_perform_mail(struct connectdata *conn)
         auth = aprintf("<%s>", address);
 
       free(address);
-      if(!from)
-        return CURLE_OUT_OF_MEMORY;
     }
     else
       /* Empty AUTH, RFC-2554, sect. 5 */
@@ -1741,10 +1738,10 @@ static CURLcode smtp_parse_custom_request(struct connectdata *conn)
  * Notes:
  *
  * Should a UTF-8 host name require conversion to IDN ACE and we cannot honor
- * that convertion then we shall return success. This allow the caller to send
+ * that conversion then we shall return success. This allow the caller to send
  * the data to the server as a U-label (as per RFC-6531 sect. 3.2).
  *
- * If an mailbox '@' seperator cannot be located then the mailbox is considered
+ * If an mailbox '@' separator cannot be located then the mailbox is considered
  * to be either a local mailbox or an invalid mailbox (depending on what the
  * calling function deems it to be) then the input will simply be returned in
  * the address part with the host name being NULL.
@@ -1765,7 +1762,7 @@ static CURLcode smtp_parse_address(struct connectdata *conn, const char *fqma,
   if(dup[length - 1] == '>')
     dup[length - 1] = '\0';
 
-  /* Extract the host name from the addresss (if we can) */
+  /* Extract the host name from the address (if we can) */
   host->name = strpbrk(dup, "@");
   if(host->name) {
     *host->name = '\0';
diff --git a/lib/socks.c b/lib/socks.c
index 37099130..18affbc9 100644
--- a/lib/socks.c
+++ b/lib/socks.c
@@ -62,13 +62,15 @@ int Curl_blockread_all(struct connectdata *conn, /* connection data */
   int result;
   *n = 0;
   for(;;) {
-    timediff_t timeleft = Curl_timeleft(conn->data, NULL, TRUE);
-    if(timeleft < 0) {
+    timediff_t timeout_ms = Curl_timeleft(conn->data, NULL, TRUE);
+    if(timeout_ms < 0) {
       /* we already got the timeout */
       result = CURLE_OPERATION_TIMEDOUT;
       break;
     }
-    if(SOCKET_READABLE(sockfd, timeleft) <= 0) {
+    if(!timeout_ms)
+      timeout_ms = TIME_T_MAX;
+    if(SOCKET_READABLE(sockfd, timeout_ms) <= 0) {
       result = ~CURLE_OK;
       break;
     }
diff --git a/lib/socks_gssapi.c b/lib/socks_gssapi.c
index 97ee7183..7f66675f 100644
--- a/lib/socks_gssapi.c
+++ b/lib/socks_gssapi.c
@@ -227,7 +227,8 @@ CURLcode Curl_SOCKS5_gssapi_negotiate(int sockindex,
 
     gss_release_buffer(&gss_status, &gss_send_token);
     gss_release_buffer(&gss_status, &gss_recv_token);
-    if(gss_major_status != GSS_S_CONTINUE_NEEDED) break;
+    if(gss_major_status != GSS_S_CONTINUE_NEEDED)
+      break;
 
     /* analyse response */
 
diff --git a/lib/transfer.c b/lib/transfer.c
index e76834eb..b9581d7a 100644
--- a/lib/transfer.c
+++ b/lib/transfer.c
@@ -48,6 +48,8 @@
 
 #ifdef HAVE_SYS_SELECT_H
 #include <sys/select.h>
+#elif defined(HAVE_UNISTD_H)
+#include <unistd.h>
 #endif
 
 #ifndef HAVE_SOCKET
@@ -568,17 +570,20 @@ static CURLcode readwrite_data(struct Curl_easy *data,
     bool is_empty_data = FALSE;
     size_t buffersize = data->set.buffer_size;
     size_t bytestoread = buffersize;
+#ifdef USE_NGHTTP2
+    bool is_http2 = ((conn->handler->protocol & PROTO_FAMILY_HTTP) &&
+                     (conn->httpversion == 20));
+#endif
 
     if(
-#if defined(USE_NGHTTP2)
+#ifdef USE_NGHTTP2
        /* For HTTP/2, read data without caring about the content
           length. This is safe because body in HTTP/2 is always
           segmented thanks to its framing layer. Meanwhile, we have to
           call Curl_read to ensure that http2_handle_stream_close is
           called when we read all incoming bytes for a particular
           stream. */
-       !((conn->handler->protocol & PROTO_FAMILY_HTTP) &&
-         conn->httpversion == 20) &&
+       !is_http2 &&
 #endif
        k->size != -1 && !k->header) {
       /* make sure we don't read too much */
@@ -621,9 +626,14 @@ static CURLcode readwrite_data(struct Curl_easy *data,
       k->buf[nread] = 0;
     }
     else {
-      /* if we receive 0 or less here, the server closed the connection
-         and we bail out from this! */
-      DEBUGF(infof(data, "nread <= 0, server closed connection, bailing\n"));
+      /* if we receive 0 or less here, either the http2 stream is closed or the
+         server closed the connection and we bail out from this! */
+#ifdef USE_NGHTTP2
+      if(is_http2 && !nread)
+        DEBUGF(infof(data, "nread == 0, stream closed, bailing\n"));
+      else
+#endif
+        DEBUGF(infof(data, "nread <= 0, server closed connection, bailing\n"));
       k->keepon &= ~KEEP_RECV;
       break;
     }
@@ -1707,12 +1717,19 @@ CURLcode Curl_follow(struct Curl_easy *data,
     break;
 
   case 303: /* See Other */
-    /* Disable both types of POSTs, unless the user explicitly
-       asks for POST after POST */
-    if(data->set.httpreq != HTTPREQ_GET
-      && !(data->set.keep_post & CURL_REDIR_POST_303)) {
-      data->set.httpreq = HTTPREQ_GET; /* enforce GET request */
-      infof(data, "Disables POST, goes with %s\n",
+    /* 'See Other' location is not the resource but a substitute for the
+     * resource. In this case we switch the method to GET/HEAD, unless the
+     * method is POST and the user specified to keep it as POST.
+     * https://github.com/curl/curl/issues/5237#issuecomment-614641049
+     */
+    if(data->set.httpreq != HTTPREQ_GET &&
+       ((data->set.httpreq != HTTPREQ_POST &&
+         data->set.httpreq != HTTPREQ_POST_FORM &&
+         data->set.httpreq != HTTPREQ_POST_MIME) ||
+        !(data->set.keep_post & CURL_REDIR_POST_303))) {
+      data->set.httpreq = HTTPREQ_GET;
+      data->set.upload = false;
+      infof(data, "Switch to %s\n",
             data->set.opt_no_body?"HEAD":"GET");
     }
     break;
@@ -1779,6 +1796,12 @@ CURLcode Curl_retry_request(struct connectdata *conn,
     retry = TRUE;
   }
   if(retry) {
+#define CONN_MAX_RETRIES 5
+    if(conn->retrycount++ >= CONN_MAX_RETRIES) {
+      failf(data, "Connection died, tried %d times before giving up",
+            CONN_MAX_RETRIES);
+      return CURLE_SEND_ERROR;
+    }
     infof(conn->data, "Connection died, retrying a fresh connect\n");
     *url = strdup(conn->data->change.url);
     if(!*url)
@@ -1821,15 +1844,21 @@ Curl_setup_transfer(
 {
   struct SingleRequest *k = &data->req;
   struct connectdata *conn = data->conn;
+  struct HTTP *http = data->req.protop;
+  bool httpsending = ((conn->handler->protocol&PROTO_FAMILY_HTTP) &&
+                      (http->sending == HTTPSEND_REQUEST));
   DEBUGASSERT(conn != NULL);
   DEBUGASSERT((sockindex <= 1) && (sockindex >= -1));
 
-  if(conn->bits.multiplex || conn->httpversion == 20) {
+  if(conn->bits.multiplex || conn->httpversion == 20 || httpsending) {
     /* when multiplexing, the read/write sockets need to be the same! */
     conn->sockfd = sockindex == -1 ?
       ((writesockindex == -1 ? CURL_SOCKET_BAD : conn->sock[writesockindex])) :
       conn->sock[sockindex];
     conn->writesockfd = conn->sockfd;
+    if(httpsending)
+      /* special and very HTTP-specific */
+      writesockindex = FIRSTSOCKET;
   }
   else {
     conn->sockfd = sockindex == -1 ?
@@ -1857,7 +1886,6 @@ Curl_setup_transfer(
       k->keepon |= KEEP_RECV;
 
     if(writesockindex != -1) {
-      struct HTTP *http = data->req.protop;
       /* HTTP 1.1 magic:
 
          Even if we require a 100-return code before uploading data, we might
diff --git a/lib/url.c b/lib/url.c
index 47fc66ae..03c27443 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -114,6 +114,7 @@ bool curl_win32_idn_to_ascii(const char *in, char **out);
 #include "http_ntlm.h"
 #include "curl_rtmp.h"
 #include "gopher.h"
+#include "mqtt.h"
 #include "http_proxy.h"
 #include "conncache.h"
 #include "multihandle.h"
@@ -232,6 +233,10 @@ static const struct Curl_handler * const protocols[] = {
   &Curl_handler_gopher,
 #endif
 
+#ifdef CURL_ENABLE_MQTT
+  &Curl_handler_mqtt,
+#endif
+
 #ifdef USE_LIBRTMP
   &Curl_handler_rtmp,
   &Curl_handler_rtmpt,
@@ -3040,7 +3045,14 @@ static CURLcode parse_connect_to_slist(struct Curl_easy *data,
 
 #ifdef USE_ALTSVC
   if(data->asi && !host && (port == -1) &&
-     (conn->handler->protocol == CURLPROTO_HTTPS)) {
+     ((conn->handler->protocol == CURLPROTO_HTTPS) ||
+#ifdef CURLDEBUG
+      /* allow debug builds to circumvent the HTTPS restriction */
+      getenv("CURL_ALTSVC_HTTP")
+#else
+      0
+#endif
+       )) {
     /* no connect_to match, try alt-svc! */
     enum alpnid srcalpnid;
     bool hit;
diff --git a/lib/urldata.h b/lib/urldata.h
index fbb8b645..50d8b84a 100644
--- a/lib/urldata.h
+++ b/lib/urldata.h
@@ -49,6 +49,7 @@
 #define PORT_RTMPT PORT_HTTP
 #define PORT_RTMPS PORT_HTTPS
 #define PORT_GOPHER 70
+#define PORT_MQTT 1883
 
 #define DICT_MATCH "/MATCH:"
 #define DICT_MATCH2 "/M:"
@@ -128,6 +129,7 @@ typedef ssize_t (Curl_recv)(struct connectdata *conn, /* connection data */
 #include "http.h"
 #include "rtsp.h"
 #include "smb.h"
+#include "mqtt.h"
 #include "wildcard.h"
 #include "multihandle.h"
 #include "quic.h"
@@ -258,6 +260,8 @@ struct ssl_config_data {
   BIT(enable_beast); /* allow this flaw for interoperability's sake*/
   BIT(no_revoke);    /* disable SSL certificate revocation checks */
   BIT(no_partialchain); /* don't accept partial certificate chains */
+  BIT(revoke_best_effort); /* ignore SSL revocation offline/missing revocation
+                              list errors */
 };
 
 struct ssl_general_config {
@@ -957,6 +961,7 @@ struct connectdata {
   curl_socket_t sock[2]; /* two sockets, the second is used for the data
                             transfer when doing FTP */
   curl_socket_t tempsock[2]; /* temporary sockets for happy eyeballs */
+  int tempfamily[2]; /* family used for the temp sockets */
   Curl_recv *recv[2];
   Curl_send *send[2];
 
@@ -1078,6 +1083,7 @@ struct connectdata {
     struct smb_conn smbc;
     void *rtmp;
     struct ldapconninfo *ldapc;
+    struct mqtt_conn mqtt;
   } proto;
 
   int cselect_bits; /* bitmask of socket events */
@@ -1098,7 +1104,7 @@ struct connectdata {
   struct http_connect_state *connect_state; /* for HTTP CONNECT */
   struct connectbundle *bundle; /* The bundle we are member of */
   int negnpn; /* APLN or NPN TLS negotiated protocol, CURL_HTTP_VERSION* */
-
+  int retrycount; /* number of retries on a new connection */
 #ifdef USE_UNIX_SOCKETS
   char *unix_domain_socket;
   BIT(abstract_unix_socket);
@@ -1113,6 +1119,8 @@ struct connectdata {
                               handle */
   BIT(sock_accepted); /* TRUE if the SECONDARYSOCKET was created with
                          accept() */
+  BIT(parallel_connect); /* set TRUE when a parallel connect attempt has
+                            started (happy eyeballs) */
 };
 
 /* The end of connectdata. */
@@ -1325,7 +1333,6 @@ struct urlpieces {
 };
 
 struct UrlState {
-
   /* Points to the connection cache */
   struct conncache *conn_cache;
 
diff --git a/lib/version.c b/lib/version.c
index 8170106e..14e50960 100644
--- a/lib/version.c
+++ b/lib/version.c
@@ -85,14 +85,17 @@ static size_t brotli_version(char *buf, size_t bufsz)
  * generate the exact same string and never write any temporary data like
  * zeros in the data.
  */
+
+#define VERSION_PARTS 14 /* number of substrings we can concatenate */
+
 char *curl_version(void)
 {
-  static char out[250];
+  static char out[300];
   char *outp;
   size_t outlen;
-  const char *src[14];
+  const char *src[VERSION_PARTS];
 #ifdef USE_SSL
-  char ssl_version[40];
+  char ssl_version[200];
 #endif
 #ifdef HAVE_LIBZ
   char z_version[40];
@@ -103,7 +106,7 @@ char *curl_version(void)
 #ifdef USE_ARES
   char cares_version[40];
 #endif
-#if defined(USE_LIBIDN2) || defined(USE_WIN32_IDN)
+#if defined(USE_LIBIDN2)
   char idn_version[40];
 #endif
 #ifdef USE_LIBPSL
@@ -127,6 +130,16 @@ char *curl_version(void)
   int i = 0;
   int j;
 
+#ifdef DEBUGBUILD
+  /* Override version string when environment variable CURL_VERSION is set */
+  const char *debugversion = getenv("CURL_VERSION");
+  if(debugversion) {
+    strncpy(out, debugversion, sizeof(out)-1);
+    out[sizeof(out)-1] = '\0';
+    return out;
+  }
+#endif
+
   src[i++] = LIBCURL_NAME "/" LIBCURL_VERSION;
 #ifdef USE_SSL
   Curl_ssl_version(ssl_version, sizeof(ssl_version));
@@ -146,14 +159,11 @@ char *curl_version(void)
   src[i++] = cares_version;
 #endif
 #ifdef USE_LIBIDN2
-  if(idn2_check_version(IDN2_VERSION)) {
-    msnprintf(idn_version, sizeof(idn_version),
-              "libidn2/%s", idn2_check_version(NULL));
-    src[i++] = idn_version;
-  }
-#elif defined(USE_WIN32_IDN)
-  msnprintf(idn_version, sizeof(idn_version), "WinIDN");
+  msnprintf(idn_version, sizeof(idn_version),
+            "libidn2/%s", idn2_check_version(NULL));
   src[i++] = idn_version;
+#elif defined(USE_WIN32_IDN)
+  src[i++] = (char *)"WinIDN";
 #endif
 
 #ifdef USE_LIBPSL
@@ -198,6 +208,8 @@ char *curl_version(void)
   }
 #endif
 
+  DEBUGASSERT(i <= VERSION_PARTS);
+
   outp = &out[0];
   outlen = sizeof(out);
   for(j = 0; j < i; j++) {
@@ -261,6 +273,9 @@ static const char * const protocols[] = {
   "ldaps",
 #endif
 #endif
+#ifdef CURL_ENABLE_MQTT
+  "mqtt",
+#endif
 #ifndef CURL_DISABLE_POP3
   "pop3",
 #endif
@@ -377,9 +392,6 @@ static curl_version_info_data version_info = {
 #if defined(USE_ALTSVC)
   | CURL_VERSION_ALTSVC
 #endif
-#ifdef USE_ESNI
-  | CURL_VERSION_ESNI
-#endif
   ,
   NULL, /* ssl_version */
   0,    /* ssl_version_num, this is kept at zero */
@@ -394,7 +406,17 @@ static curl_version_info_data version_info = {
   NULL, /* brotli version */
   0,    /* nghttp2 version number */
   NULL, /* nghttp2 version string */
-  NULL  /* quic library string */
+  NULL, /* quic library string */
+#ifdef CURL_CA_BUNDLE
+  CURL_CA_BUNDLE, /* cainfo */
+#else
+  NULL,
+#endif
+#ifdef CURL_CA_PATH
+  CURL_CA_PATH  /* capath */
+#else
+  NULL
+#endif
 };
 
 curl_version_info_data *curl_version_info(CURLversion stamp)
diff --git a/lib/vquic/ngtcp2.c b/lib/vquic/ngtcp2.c
index 2f6ee8bd..5f7b6e2e 100644
--- a/lib/vquic/ngtcp2.c
+++ b/lib/vquic/ngtcp2.c
@@ -26,7 +26,9 @@
 #include <ngtcp2/ngtcp2.h>
 #include <ngtcp2/ngtcp2_crypto.h>
 #include <nghttp3/nghttp3.h>
+#ifdef USE_OPENSSL
 #include <openssl/err.h>
+#endif
 #include "urldata.h"
 #include "sendf.h"
 #include "strdup.h"
@@ -69,10 +71,18 @@ struct h3out {
 #define QUIC_MAX_STREAMS (256*1024)
 #define QUIC_MAX_DATA (1*1024*1024)
 #define QUIC_IDLE_TIMEOUT 60000 /* milliseconds */
+
+#ifdef USE_OPENSSL
 #define QUIC_CIPHERS                                                          \
   "TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_"               \
   "POLY1305_SHA256:TLS_AES_128_CCM_SHA256"
 #define QUIC_GROUPS "P-256:X25519:P-384:P-521"
+#elif defined(USE_GNUTLS)
+#define QUIC_PRIORITY \
+  "NORMAL:-VERS-ALL:+VERS-TLS1.3:-CIPHER-ALL:+AES-128-GCM:+AES-256-GCM:" \
+  "+CHACHA20-POLY1305:+AES-128-CCM:-GROUP-ALL:+GROUP-SECP256R1:" \
+  "+GROUP-X25519:+GROUP-SECP384R1:+GROUP-SECP521R1"
+#endif
 
 static CURLcode ng_process_ingress(struct connectdata *conn,
                                    curl_socket_t sockfd,
@@ -101,6 +111,7 @@ static void quic_printf(void *user_data, const char *fmt, ...)
 }
 #endif
 
+#ifdef USE_OPENSSL
 static ngtcp2_crypto_level
 quic_from_ossl_level(OSSL_ENCRYPTION_LEVEL ossl_level)
 {
@@ -117,14 +128,32 @@ quic_from_ossl_level(OSSL_ENCRYPTION_LEVEL ossl_level)
     assert(0);
   }
 }
+#elif defined(USE_GNUTLS)
+static ngtcp2_crypto_level
+quic_from_gtls_level(gnutls_record_encryption_level_t gtls_level)
+{
+  switch(gtls_level) {
+  case GNUTLS_ENCRYPTION_LEVEL_INITIAL:
+    return NGTCP2_CRYPTO_LEVEL_INITIAL;
+  case GNUTLS_ENCRYPTION_LEVEL_EARLY:
+    return NGTCP2_CRYPTO_LEVEL_EARLY;
+  case GNUTLS_ENCRYPTION_LEVEL_HANDSHAKE:
+    return NGTCP2_CRYPTO_LEVEL_HANDSHAKE;
+  case GNUTLS_ENCRYPTION_LEVEL_APPLICATION:
+    return NGTCP2_CRYPTO_LEVEL_APP;
+  default:
+    assert(0);
+  }
+}
+#endif
 
 static int setup_initial_crypto_context(struct quicsocket *qs)
 {
   const ngtcp2_cid *dcid = ngtcp2_conn_get_dcid(qs->qconn);
 
   if(ngtcp2_crypto_derive_and_install_initial_key(
-         qs->qconn, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, dcid,
-         NGTCP2_CRYPTO_SIDE_CLIENT) != 0)
+         qs->qconn, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+         dcid) != 0)
     return -1;
 
   return 0;
@@ -150,6 +179,7 @@ static void quic_settings(ngtcp2_settings *s,
 }
 
 static FILE *keylog_file; /* not thread-safe */
+#ifdef USE_OPENSSL
 static void keylog_callback(const SSL *ssl, const char *line)
 {
   (void)ssl;
@@ -157,37 +187,52 @@ static void keylog_callback(const SSL *ssl, const char *line)
   fputc('\n', keylog_file);
   fflush(keylog_file);
 }
-
-static int init_ngh3_conn(struct quicsocket *qs);
-
-static int quic_set_encryption_secrets(SSL *ssl,
-                                       OSSL_ENCRYPTION_LEVEL ossl_level,
-                                       const uint8_t *rx_secret,
-                                       const uint8_t *tx_secret,
-                                       size_t secretlen)
+#elif defined(USE_GNUTLS)
+static int keylog_callback(gnutls_session_t session, const char *label,
+                    const gnutls_datum_t *secret)
 {
-  struct quicsocket *qs = (struct quicsocket *)SSL_get_app_data(ssl);
-  int level = quic_from_ossl_level(ossl_level);
+  gnutls_datum_t crandom;
+  gnutls_datum_t srandom;
+  gnutls_datum_t crandom_hex = { NULL, 0 };
+  gnutls_datum_t secret_hex = { NULL, 0 };
+  int rc = 0;
+
+  gnutls_session_get_random(session, &crandom, &srandom);
+  if(crandom.size != 32) {
+    return -1;
+  }
 
-  if(ngtcp2_crypto_derive_and_install_key(
-         qs->qconn, ssl, NULL, NULL, NULL, NULL, NULL, NULL, level, rx_secret,
-         tx_secret, secretlen, NGTCP2_CRYPTO_SIDE_CLIENT) != 0)
-    return 0;
+  rc = gnutls_hex_encode2(&crandom, &crandom_hex);
+  if(rc < 0) {
+    fprintf(stderr, "gnutls_hex_encode2 failed: %s\n",
+            gnutls_strerror(rc));
+    goto out;
+  }
 
-  if(level == NGTCP2_CRYPTO_LEVEL_APP) {
-    if(init_ngh3_conn(qs) != CURLE_OK)
-      return 0;
+  rc = gnutls_hex_encode2(secret, &secret_hex);
+  if(rc < 0) {
+    fprintf(stderr, "gnutls_hex_encode2 failed: %s\n",
+            gnutls_strerror(rc));
+    goto out;
   }
 
-  return 1;
+  fprintf(keylog_file, "%s %s %s\n", label, crandom_hex.data, secret_hex.data);
+  fflush(keylog_file);
+
+ out:
+  gnutls_free(crandom_hex.data);
+  gnutls_free(secret_hex.data);
+  return rc;
 }
+#endif
 
-static int quic_add_handshake_data(SSL *ssl, OSSL_ENCRYPTION_LEVEL ossl_level,
-                                   const uint8_t *data, size_t len)
+static int init_ngh3_conn(struct quicsocket *qs);
+
+static int write_client_handshake(struct quicsocket *qs,
+                                  ngtcp2_crypto_level level,
+                                  const uint8_t *data, size_t len)
 {
-  struct quicsocket *qs = (struct quicsocket *)SSL_get_app_data(ssl);
   struct quic_handshake *crypto_data;
-  ngtcp2_crypto_level level = quic_from_ossl_level(ossl_level);
   int rv;
 
   crypto_data = &qs->crypto_data[level];
@@ -216,6 +261,42 @@ static int quic_add_handshake_data(SSL *ssl, OSSL_ENCRYPTION_LEVEL ossl_level,
   return 1;
 }
 
+#ifdef USE_OPENSSL
+static int quic_set_encryption_secrets(SSL *ssl,
+                                       OSSL_ENCRYPTION_LEVEL ossl_level,
+                                       const uint8_t *rx_secret,
+                                       const uint8_t *tx_secret,
+                                       size_t secretlen)
+{
+  struct quicsocket *qs = (struct quicsocket *)SSL_get_app_data(ssl);
+  int level = quic_from_ossl_level(ossl_level);
+
+  if(level != NGTCP2_CRYPTO_LEVEL_EARLY &&
+     ngtcp2_crypto_derive_and_install_rx_key(
+         qs->qconn, ssl, NULL, NULL, NULL, level, rx_secret, secretlen) != 0)
+    return 0;
+
+  if(ngtcp2_crypto_derive_and_install_tx_key(
+         qs->qconn, ssl, NULL, NULL, NULL, level, tx_secret, secretlen) != 0)
+    return 0;
+
+  if(level == NGTCP2_CRYPTO_LEVEL_APP) {
+    if(init_ngh3_conn(qs) != CURLE_OK)
+      return 0;
+  }
+
+  return 1;
+}
+
+static int quic_add_handshake_data(SSL *ssl, OSSL_ENCRYPTION_LEVEL ossl_level,
+                                   const uint8_t *data, size_t len)
+{
+  struct quicsocket *qs = (struct quicsocket *)SSL_get_app_data(ssl);
+  ngtcp2_crypto_level level = quic_from_ossl_level(ossl_level);
+
+  return write_client_handshake(qs, level, data, len);
+}
+
 static int quic_flush_flight(SSL *ssl)
 {
   (void)ssl;
@@ -303,6 +384,193 @@ static int quic_init_ssl(struct quicsocket *qs)
   SSL_set_tlsext_host_name(qs->ssl, hostname);
   return 0;
 }
+#elif defined(USE_GNUTLS)
+static int secret_func(gnutls_session_t ssl,
+                       gnutls_record_encryption_level_t gtls_level,
+                       const void *rx_secret,
+                       const void *tx_secret, size_t secretlen)
+{
+  struct quicsocket *qs = gnutls_session_get_ptr(ssl);
+  int level = quic_from_gtls_level(gtls_level);
+
+  if(level != NGTCP2_CRYPTO_LEVEL_EARLY &&
+     ngtcp2_crypto_derive_and_install_rx_key(
+         qs->qconn, ssl, NULL, NULL, NULL, level, rx_secret, secretlen) != 0)
+    return 0;
+
+  if(ngtcp2_crypto_derive_and_install_tx_key(
+         qs->qconn, ssl, NULL, NULL, NULL, level, tx_secret, secretlen) != 0)
+    return 0;
+
+  if(level == NGTCP2_CRYPTO_LEVEL_APP) {
+    if(init_ngh3_conn(qs) != CURLE_OK)
+      return -1;
+  }
+
+  return 0;
+}
+
+static int read_func(gnutls_session_t ssl,
+                     gnutls_record_encryption_level_t gtls_level,
+                     gnutls_handshake_description_t htype, const void *data,
+                     size_t len)
+{
+  struct quicsocket *qs = gnutls_session_get_ptr(ssl);
+  ngtcp2_crypto_level level = quic_from_gtls_level(gtls_level);
+  int rv;
+
+  if(htype == GNUTLS_HANDSHAKE_CHANGE_CIPHER_SPEC)
+    return 0;
+
+  rv = write_client_handshake(qs, level, data, len);
+  if(rv == 0)
+    return -1;
+
+  return 0;
+}
+
+static int alert_read_func(gnutls_session_t ssl,
+                           gnutls_record_encryption_level_t gtls_level,
+                           gnutls_alert_level_t alert_level,
+                           gnutls_alert_description_t alert_desc)
+{
+  struct quicsocket *qs = gnutls_session_get_ptr(ssl);
+  (void)gtls_level;
+  (void)alert_level;
+
+  qs->tls_alert = alert_desc;
+  return 1;
+}
+
+static int tp_recv_func(gnutls_session_t ssl, const uint8_t *data,
+                        size_t data_size)
+{
+  struct quicsocket *qs = gnutls_session_get_ptr(ssl);
+  ngtcp2_transport_params params;
+
+  if(ngtcp2_decode_transport_params(
+         &params, NGTCP2_TRANSPORT_PARAMS_TYPE_ENCRYPTED_EXTENSIONS,
+         data, data_size) != 0)
+    return -1;
+
+  if(ngtcp2_conn_set_remote_transport_params(qs->qconn, &params) != 0)
+    return -1;
+
+  return 0;
+}
+
+static int tp_send_func(gnutls_session_t ssl, gnutls_buffer_t extdata)
+{
+  struct quicsocket *qs = gnutls_session_get_ptr(ssl);
+  uint8_t paramsbuf[64];
+  ngtcp2_transport_params params;
+  ssize_t nwrite;
+  int rc;
+
+  ngtcp2_conn_get_local_transport_params(qs->qconn, &params);
+  nwrite = ngtcp2_encode_transport_params(
+    paramsbuf, sizeof(paramsbuf), NGTCP2_TRANSPORT_PARAMS_TYPE_CLIENT_HELLO,
+    &params);
+  if(nwrite < 0) {
+    fprintf(stderr, "ngtcp2_encode_transport_params: %s\n",
+          ngtcp2_strerror((int)nwrite));
+    return -1;
+  }
+
+  rc = gnutls_buffer_append_data(extdata, paramsbuf, nwrite);
+  if(rc < 0)
+    return rc;
+
+  return (int)nwrite;
+}
+
+static int quic_init_ssl(struct quicsocket *qs)
+{
+  gnutls_datum_t alpn = {NULL, 0};
+  /* this will need some attention when HTTPS proxy over QUIC get fixed */
+  const char * const hostname = qs->conn->host.name;
+  const char *keylog_filename;
+  int rc;
+
+  if(qs->ssl)
+    gnutls_deinit(qs->ssl);
+
+  gnutls_init(&qs->ssl, GNUTLS_CLIENT);
+  gnutls_session_set_ptr(qs->ssl, qs);
+
+  rc = gnutls_priority_set_direct(qs->ssl, QUIC_PRIORITY, NULL);
+  if(rc < 0) {
+    fprintf(stderr, "gnutls_priority_set_direct failed: %s\n",
+            gnutls_strerror(rc));
+    return 1;
+  }
+
+  gnutls_handshake_set_secret_function(qs->ssl, secret_func);
+  gnutls_handshake_set_read_function(qs->ssl, read_func);
+  gnutls_alert_set_read_function(qs->ssl, alert_read_func);
+
+  rc = gnutls_session_ext_register(qs->ssl, "QUIC Transport Parameters",
+                                   0xffa5, GNUTLS_EXT_TLS,
+                                   tp_recv_func, tp_send_func,
+                                   NULL, NULL, NULL,
+                                   GNUTLS_EXT_FLAG_TLS |
+                                   GNUTLS_EXT_FLAG_CLIENT_HELLO |
+                                   GNUTLS_EXT_FLAG_EE);
+  if(rc < 0) {
+    fprintf(stderr, "gnutls_session_ext_register failed: %s\n",
+            gnutls_strerror(rc));
+    return 1;
+  }
+
+  keylog_filename = getenv("SSLKEYLOGFILE");
+  if(keylog_filename) {
+    keylog_file = fopen(keylog_filename, "wb");
+    if(keylog_file) {
+      gnutls_session_set_keylog_function(qs->ssl, keylog_callback);
+    }
+  }
+
+  if(qs->cred)
+    gnutls_certificate_free_credentials(qs->cred);
+
+  rc = gnutls_certificate_allocate_credentials(&qs->cred);
+  if(rc < 0) {
+    fprintf(stderr, "gnutls_certificate_allocate_credentials failed: %s\n",
+            gnutls_strerror(rc));
+    return 1;
+  }
+
+  rc = gnutls_certificate_set_x509_system_trust(qs->cred);
+  if(rc < 0) {
+    fprintf(stderr, "gnutls_certificate_set_x509_system_trust failed: %s\n",
+            gnutls_strerror(rc));
+    return 1;
+  }
+
+  rc = gnutls_credentials_set(qs->ssl, GNUTLS_CRD_CERTIFICATE, qs->cred);
+  if(rc < 0) {
+    fprintf(stderr, "gnutls_credentials_set failed: %s\n",
+            gnutls_strerror(rc));
+    return 1;
+  }
+
+  switch(qs->version) {
+#ifdef NGTCP2_PROTO_VER
+  case NGTCP2_PROTO_VER:
+    /* strip the first byte from NGTCP2_ALPN_H3 */
+    alpn.data = (unsigned char *)NGTCP2_ALPN_H3 + 1;
+    alpn.size = sizeof(NGTCP2_ALPN_H3) - 2;
+    break;
+#endif
+  }
+  if(alpn.data)
+    gnutls_alpn_set_protocols(qs->ssl, &alpn, 1, 0);
+
+  /* set SNI */
+  gnutls_server_name_set(qs->ssl, GNUTLS_NAME_DNS, hostname, strlen(hostname));
+  return 0;
+}
+#endif
 
 static int cb_initial(ngtcp2_conn *quic, void *user_data)
 {
@@ -556,9 +824,11 @@ CURLcode Curl_quic_connect(struct connectdata *conn,
   struct quicsocket *qs = &conn->hequic[sockindex];
   char ipbuf[40];
   long port;
+#ifdef USE_OPENSSL
   uint8_t paramsbuf[64];
   ngtcp2_transport_params params;
   ssize_t nwrite;
+#endif
 
   qs->conn = conn;
 
@@ -574,9 +844,11 @@ CURLcode Curl_quic_connect(struct connectdata *conn,
         sockfd, ipbuf, port);
 
   qs->version = NGTCP2_PROTO_VER;
+#ifdef USE_OPENSSL
   qs->sslctx = quic_ssl_ctx(data);
   if(!qs->sslctx)
     return CURLE_QUIC_CONNECT_ERROR;
+#endif
 
   if(quic_init_ssl(qs))
     return CURLE_QUIC_CONNECT_ERROR;
@@ -613,6 +885,7 @@ CURLcode Curl_quic_connect(struct connectdata *conn,
   if(rc)
     return CURLE_QUIC_CONNECT_ERROR;
 
+#ifdef USE_OPENSSL
   ngtcp2_conn_get_local_transport_params(qs->qconn, &params);
   nwrite = ngtcp2_encode_transport_params(
     paramsbuf, sizeof(paramsbuf), NGTCP2_TRANSPORT_PARAMS_TYPE_CLIENT_HELLO,
@@ -625,6 +898,7 @@ CURLcode Curl_quic_connect(struct connectdata *conn,
 
   if(!SSL_set_quic_transport_params(qs->ssl, paramsbuf, nwrite))
     return CURLE_QUIC_CONNECT_ERROR;
+#endif
 
   rc = setup_initial_crypto_context(qs);
   if(rc)
@@ -676,12 +950,22 @@ static CURLcode ng_disconnect(struct connectdata *conn,
   struct quicsocket *qs = &conn->hequic[0];
   (void)dead_connection;
   if(qs->ssl)
+#ifdef USE_OPENSSL
     SSL_free(qs->ssl);
+#elif defined(USE_GNUTLS)
+    gnutls_deinit(qs->ssl);
+#endif
+#ifdef USE_GNUTLS
+  if(qs->cred)
+    gnutls_certificate_free_credentials(qs->cred);
+#endif
   for(i = 0; i < 3; i++)
     free(qs->crypto_data[i].buf);
   nghttp3_conn_del(qs->h3conn);
   ngtcp2_conn_del(qs->qconn);
+#ifdef USE_OPENSSL
   SSL_CTX_free(qs->sslctx);
+#endif
   return CURLE_OK;
 }
 
diff --git a/lib/vquic/ngtcp2.h b/lib/vquic/ngtcp2.h
index 30d442fd..06337f6f 100644
--- a/lib/vquic/ngtcp2.h
+++ b/lib/vquic/ngtcp2.h
@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -28,7 +28,11 @@
 
 #include <ngtcp2/ngtcp2.h>
 #include <nghttp3/nghttp3.h>
+#ifdef USE_OPENSSL
 #include <openssl/ssl.h>
+#elif defined(USE_GNUTLS)
+#include <gnutls/gnutls.h>
+#endif
 
 struct quic_handshake {
   char *buf;       /* pointer to the buffer */
@@ -44,8 +48,13 @@ struct quicsocket {
   ngtcp2_cid scid;
   uint32_t version;
   ngtcp2_settings settings;
+#ifdef USE_OPENSSL
   SSL_CTX *sslctx;
   SSL *ssl;
+#elif defined(USE_GNUTLS)
+  gnutls_certificate_credentials_t cred;
+  gnutls_session_t ssl;
+#endif
   struct quic_handshake crypto_data[3];
   /* the last TLS alert description generated by the local endpoint */
   uint8_t tls_alert;
diff --git a/lib/vssh/libssh.c b/lib/vssh/libssh.c
index 08d9f9e0..8988e239 100644
--- a/lib/vssh/libssh.c
+++ b/lib/vssh/libssh.c
@@ -403,6 +403,9 @@ static int myssh_is_known(struct connectdata *conn)
           knownkey.keytype = CURLKHTYPE_RSA1;
           break;
         case SSH_KEYTYPE_ECDSA:
+        case SSH_KEYTYPE_ECDSA_P256:
+        case SSH_KEYTYPE_ECDSA_P384:
+        case SSH_KEYTYPE_ECDSA_P521:
           knownkey.keytype = CURLKHTYPE_ECDSA;
           break;
         case SSH_KEYTYPE_ED25519:
@@ -470,6 +473,11 @@ static int myssh_is_known(struct connectdata *conn)
         foundkey.keytype = CURLKHTYPE_RSA1;
         break;
       case SSH_KEYTYPE_ECDSA:
+#if LIBSSH_VERSION_INT >= SSH_VERSION_INT(0,9,0)
+      case SSH_KEYTYPE_ECDSA_P256:
+      case SSH_KEYTYPE_ECDSA_P384:
+      case SSH_KEYTYPE_ECDSA_P521:
+#endif
         foundkey.keytype = CURLKHTYPE_ECDSA;
         break;
 #if LIBSSH_VERSION_INT >= SSH_VERSION_INT(0,7,0)
@@ -2141,6 +2149,7 @@ static CURLcode myssh_connect(struct connectdata *conn, bool *done)
   CURLcode result;
   curl_socket_t sock = conn->sock[FIRSTSOCKET];
   struct Curl_easy *data = conn->data;
+  int rc;
 
   /* initialize per-handle data if not already */
   if(!data->req.protop)
@@ -2167,38 +2176,70 @@ static CURLcode myssh_connect(struct connectdata *conn, bool *done)
     return CURLE_FAILED_INIT;
   }
 
-  ssh_options_set(ssh->ssh_session, SSH_OPTIONS_FD, &sock);
+  rc = ssh_options_set(ssh->ssh_session, SSH_OPTIONS_HOST, conn->host.name);
+  if(rc != SSH_OK) {
+    failf(data, "Could not set remote host");
+    return CURLE_FAILED_INIT;
+  }
+
+  rc = ssh_options_parse_config(ssh->ssh_session, NULL);
+  if(rc != SSH_OK) {
+    infof(data, "Could not parse SSH configuration files");
+    /* ignore */
+  }
+
+  rc = ssh_options_set(ssh->ssh_session, SSH_OPTIONS_FD, &sock);
+  if(rc != SSH_OK) {
+    failf(data, "Could not set socket");
+    return CURLE_FAILED_INIT;
+  }
 
-  if(conn->user) {
+  if(conn->user && conn->user[0] != '\0') {
     infof(data, "User: %s\n", conn->user);
-    ssh_options_set(ssh->ssh_session, SSH_OPTIONS_USER, conn->user);
+    rc = ssh_options_set(ssh->ssh_session, SSH_OPTIONS_USER, conn->user);
+    if(rc != SSH_OK) {
+      failf(data, "Could not set user");
+      return CURLE_FAILED_INIT;
+    }
   }
 
   if(data->set.str[STRING_SSH_KNOWNHOSTS]) {
     infof(data, "Known hosts: %s\n", data->set.str[STRING_SSH_KNOWNHOSTS]);
-    ssh_options_set(ssh->ssh_session, SSH_OPTIONS_KNOWNHOSTS,
-                    data->set.str[STRING_SSH_KNOWNHOSTS]);
+    rc = ssh_options_set(ssh->ssh_session, SSH_OPTIONS_KNOWNHOSTS,
+                         data->set.str[STRING_SSH_KNOWNHOSTS]);
+    if(rc != SSH_OK) {
+      failf(data, "Could not set known hosts file path");
+      return CURLE_FAILED_INIT;
+    }
   }
 
-  ssh_options_set(ssh->ssh_session, SSH_OPTIONS_HOST, conn->host.name);
-  if(conn->remote_port)
-    ssh_options_set(ssh->ssh_session, SSH_OPTIONS_PORT,
-                    &conn->remote_port);
+  if(conn->remote_port) {
+    rc = ssh_options_set(ssh->ssh_session, SSH_OPTIONS_PORT,
+                         &conn->remote_port);
+    if(rc != SSH_OK) {
+      failf(data, "Could not set remote port");
+      return CURLE_FAILED_INIT;
+    }
+  }
 
   if(data->set.ssh_compression) {
-    ssh_options_set(ssh->ssh_session, SSH_OPTIONS_COMPRESSION,
-                    "zlib,zlib@openssh.com,none");
+    rc = ssh_options_set(ssh->ssh_session, SSH_OPTIONS_COMPRESSION,
+                         "zlib,zlib@openssh.com,none");
+    if(rc != SSH_OK) {
+      failf(data, "Could not set compression");
+      return CURLE_FAILED_INIT;
+    }
   }
 
   ssh->privkey = NULL;
   ssh->pubkey = NULL;
 
   if(data->set.str[STRING_SSH_PUBLIC_KEY]) {
-    int rc = ssh_pki_import_pubkey_file(data->set.str[STRING_SSH_PUBLIC_KEY],
-                                        &ssh->pubkey);
+    rc = ssh_pki_import_pubkey_file(data->set.str[STRING_SSH_PUBLIC_KEY],
+                                    &ssh->pubkey);
     if(rc != SSH_OK) {
       failf(data, "Could not load public key file");
-      /* ignore */
+      return CURLE_FAILED_INIT;
     }
   }
 
diff --git a/lib/vtls/bearssl.c b/lib/vtls/bearssl.c
index 67f94583..1a6530c8 100644
--- a/lib/vtls/bearssl.c
+++ b/lib/vtls/bearssl.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 2019, Michael Forney, <mforney@mforney.org>
+ * Copyright (C) 2019 - 2020, Michael Forney, <mforney@mforney.org>
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -56,8 +56,6 @@ struct ssl_backend_data {
   size_t pending_write;
 };
 
-#define BACKEND connssl->backend
-
 struct cafile_parser {
   CURLcode err;
   bool in_cert;
@@ -300,6 +298,7 @@ static CURLcode bearssl_connect_step1(struct connectdata *conn, int sockindex)
 {
   struct Curl_easy *data = conn->data;
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   const char * const ssl_cafile = SSL_CONN_CONFIG(CAfile);
   const char *hostname = SSL_IS_PROXY() ? conn->http_proxy.host.name :
     conn->host.name;
@@ -343,7 +342,7 @@ static CURLcode bearssl_connect_step1(struct connectdata *conn, int sockindex)
   }
 
   if(ssl_cafile) {
-    ret = load_cafile(ssl_cafile, &BACKEND->anchors, &BACKEND->anchors_len);
+    ret = load_cafile(ssl_cafile, &backend->anchors, &backend->anchors_len);
     if(ret != CURLE_OK) {
       if(verifypeer) {
         failf(data, "error setting certificate verify locations:\n"
@@ -356,24 +355,24 @@ static CURLcode bearssl_connect_step1(struct connectdata *conn, int sockindex)
   }
 
   /* initialize SSL context */
-  br_ssl_client_init_full(&BACKEND->ctx, &BACKEND->x509.minimal,
-                          BACKEND->anchors, BACKEND->anchors_len);
-  br_ssl_engine_set_versions(&BACKEND->ctx.eng, version_min, version_max);
-  br_ssl_engine_set_buffer(&BACKEND->ctx.eng, BACKEND->buf,
-                           sizeof(BACKEND->buf), 1);
+  br_ssl_client_init_full(&backend->ctx, &backend->x509.minimal,
+                          backend->anchors, backend->anchors_len);
+  br_ssl_engine_set_versions(&backend->ctx.eng, version_min, version_max);
+  br_ssl_engine_set_buffer(&backend->ctx.eng, backend->buf,
+                           sizeof(backend->buf), 1);
 
   /* initialize X.509 context */
-  BACKEND->x509.vtable = &x509_vtable;
-  BACKEND->x509.verifypeer = verifypeer;
-  BACKEND->x509.verifyhost = verifyhost;
-  br_ssl_engine_set_x509(&BACKEND->ctx.eng, &BACKEND->x509.vtable);
+  backend->x509.vtable = &x509_vtable;
+  backend->x509.verifypeer = verifypeer;
+  backend->x509.verifyhost = verifyhost;
+  br_ssl_engine_set_x509(&backend->ctx.eng, &backend->x509.vtable);
 
   if(SSL_SET_OPTION(primary.sessionid)) {
     void *session;
 
     Curl_ssl_sessionid_lock(conn);
     if(!Curl_ssl_getsessionid(conn, &session, NULL, sockindex)) {
-      br_ssl_engine_set_session_parameters(&BACKEND->ctx.eng, session);
+      br_ssl_engine_set_session_parameters(&backend->ctx.eng, session);
       infof(data, "BearSSL: re-using session ID\n");
     }
     Curl_ssl_sessionid_unlock(conn);
@@ -389,16 +388,16 @@ static CURLcode bearssl_connect_step1(struct connectdata *conn, int sockindex)
 #ifdef USE_NGHTTP2
     if(data->set.httpversion >= CURL_HTTP_VERSION_2 &&
        (!SSL_IS_PROXY() || !conn->bits.tunnel_proxy)) {
-      BACKEND->protocols[cur++] = NGHTTP2_PROTO_VERSION_ID;
+      backend->protocols[cur++] = NGHTTP2_PROTO_VERSION_ID;
       infof(data, "ALPN, offering %s\n", NGHTTP2_PROTO_VERSION_ID);
     }
 #endif
 
-    BACKEND->protocols[cur++] = ALPN_HTTP_1_1;
+    backend->protocols[cur++] = ALPN_HTTP_1_1;
     infof(data, "ALPN, offering %s\n", ALPN_HTTP_1_1);
 
-    br_ssl_engine_set_protocol_names(&BACKEND->ctx.eng,
-                                     BACKEND->protocols, cur);
+    br_ssl_engine_set_protocol_names(&backend->ctx.eng,
+                                     backend->protocols, cur);
   }
 
   if((1 == Curl_inet_pton(AF_INET, hostname, &addr))
@@ -414,9 +413,9 @@ static CURLcode bearssl_connect_step1(struct connectdata *conn, int sockindex)
     hostname = NULL;
   }
 
-  if(!br_ssl_client_reset(&BACKEND->ctx, hostname, 0))
+  if(!br_ssl_client_reset(&backend->ctx, hostname, 0))
     return CURLE_FAILED_INIT;
-  BACKEND->active = TRUE;
+  backend->active = TRUE;
 
   connssl->connecting_state = ssl_connect_2;
 
@@ -428,6 +427,7 @@ static CURLcode bearssl_run_until(struct connectdata *conn, int sockindex,
 {
   struct Curl_easy *data = conn->data;
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   curl_socket_t sockfd = conn->sock[sockindex];
   unsigned state;
   unsigned char *buf;
@@ -436,9 +436,9 @@ static CURLcode bearssl_run_until(struct connectdata *conn, int sockindex,
   int err;
 
   for(;;) {
-    state = br_ssl_engine_current_state(&BACKEND->ctx.eng);
+    state = br_ssl_engine_current_state(&backend->ctx.eng);
     if(state & BR_SSL_CLOSED) {
-      err = br_ssl_engine_last_error(&BACKEND->ctx.eng);
+      err = br_ssl_engine_last_error(&backend->ctx.eng);
       switch(err) {
       case BR_ERR_OK:
         /* TLS close notify */
@@ -468,7 +468,7 @@ static CURLcode bearssl_run_until(struct connectdata *conn, int sockindex,
     if(state & target)
       return CURLE_OK;
     if(state & BR_SSL_SENDREC) {
-      buf = br_ssl_engine_sendrec_buf(&BACKEND->ctx.eng, &len);
+      buf = br_ssl_engine_sendrec_buf(&backend->ctx.eng, &len);
       ret = swrite(sockfd, buf, len);
       if(ret == -1) {
         if(SOCKERRNO == EAGAIN || SOCKERRNO == EWOULDBLOCK) {
@@ -478,10 +478,10 @@ static CURLcode bearssl_run_until(struct connectdata *conn, int sockindex,
         }
         return CURLE_WRITE_ERROR;
       }
-      br_ssl_engine_sendrec_ack(&BACKEND->ctx.eng, ret);
+      br_ssl_engine_sendrec_ack(&backend->ctx.eng, ret);
     }
     else if(state & BR_SSL_RECVREC) {
-      buf = br_ssl_engine_recvrec_buf(&BACKEND->ctx.eng, &len);
+      buf = br_ssl_engine_recvrec_buf(&backend->ctx.eng, &len);
       ret = sread(sockfd, buf, len);
       if(ret == 0) {
         failf(data, "SSL: EOF without close notify");
@@ -495,7 +495,7 @@ static CURLcode bearssl_run_until(struct connectdata *conn, int sockindex,
         }
         return CURLE_READ_ERROR;
       }
-      br_ssl_engine_recvrec_ack(&BACKEND->ctx.eng, ret);
+      br_ssl_engine_recvrec_ack(&backend->ctx.eng, ret);
     }
   }
 }
@@ -504,13 +504,14 @@ static CURLcode bearssl_connect_step2(struct connectdata *conn, int sockindex)
 {
   struct Curl_easy *data = conn->data;
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   CURLcode ret;
 
   ret = bearssl_run_until(conn, sockindex, BR_SSL_SENDAPP | BR_SSL_RECVAPP);
   if(ret == CURLE_AGAIN)
     return CURLE_OK;
   if(ret == CURLE_OK) {
-    if(br_ssl_engine_current_state(&BACKEND->ctx.eng) == BR_SSL_CLOSED) {
+    if(br_ssl_engine_current_state(&backend->ctx.eng) == BR_SSL_CLOSED) {
       failf(data, "SSL: connection closed during handshake");
       return CURLE_SSL_CONNECT_ERROR;
     }
@@ -523,6 +524,7 @@ static CURLcode bearssl_connect_step3(struct connectdata *conn, int sockindex)
 {
   struct Curl_easy *data = conn->data;
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   CURLcode ret;
 
   DEBUGASSERT(ssl_connect_3 == connssl->connecting_state);
@@ -530,7 +532,7 @@ static CURLcode bearssl_connect_step3(struct connectdata *conn, int sockindex)
   if(conn->bits.tls_enable_alpn) {
     const char *protocol;
 
-    protocol = br_ssl_engine_get_selected_protocol(&BACKEND->ctx.eng);
+    protocol = br_ssl_engine_get_selected_protocol(&backend->ctx.eng);
     if(protocol) {
       infof(data, "ALPN, server accepted to use %s\n", protocol);
 
@@ -558,7 +560,7 @@ static CURLcode bearssl_connect_step3(struct connectdata *conn, int sockindex)
     session = malloc(sizeof(*session));
     if(!session)
       return CURLE_OUT_OF_MEMORY;
-    br_ssl_engine_get_session_parameters(&BACKEND->ctx.eng, session);
+    br_ssl_engine_get_session_parameters(&backend->ctx.eng, session);
     Curl_ssl_sessionid_lock(conn);
     incache = !(Curl_ssl_getsessionid(conn, &oldsession, NULL, sockindex));
     if(incache)
@@ -581,6 +583,7 @@ static ssize_t bearssl_send(struct connectdata *conn, int sockindex,
 {
   struct Curl_easy *data = conn->data;
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   unsigned char *app;
   size_t applen;
 
@@ -588,23 +591,23 @@ static ssize_t bearssl_send(struct connectdata *conn, int sockindex,
     *err = bearssl_run_until(conn, sockindex, BR_SSL_SENDAPP);
     if (*err != CURLE_OK)
       return -1;
-    app = br_ssl_engine_sendapp_buf(&BACKEND->ctx.eng, &applen);
+    app = br_ssl_engine_sendapp_buf(&backend->ctx.eng, &applen);
     if(!app) {
       failf(data, "SSL: connection closed during write");
       *err = CURLE_SEND_ERROR;
       return -1;
     }
-    if(BACKEND->pending_write) {
-      applen = BACKEND->pending_write;
-      BACKEND->pending_write = 0;
+    if(backend->pending_write) {
+      applen = backend->pending_write;
+      backend->pending_write = 0;
       return applen;
     }
     if(applen > len)
       applen = len;
     memcpy(app, buf, applen);
-    br_ssl_engine_sendapp_ack(&BACKEND->ctx.eng, applen);
-    br_ssl_engine_flush(&BACKEND->ctx.eng, 0);
-    BACKEND->pending_write = applen;
+    br_ssl_engine_sendapp_ack(&backend->ctx.eng, applen);
+    br_ssl_engine_flush(&backend->ctx.eng, 0);
+    backend->pending_write = applen;
   }
 }
 
@@ -612,19 +615,20 @@ static ssize_t bearssl_recv(struct connectdata *conn, int sockindex,
                             char *buf, size_t len, CURLcode *err)
 {
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   unsigned char *app;
   size_t applen;
 
   *err = bearssl_run_until(conn, sockindex, BR_SSL_RECVAPP);
   if(*err != CURLE_OK)
     return -1;
-  app = br_ssl_engine_recvapp_buf(&BACKEND->ctx.eng, &applen);
+  app = br_ssl_engine_recvapp_buf(&backend->ctx.eng, &applen);
   if(!app)
     return 0;
   if(applen > len)
     applen = len;
   memcpy(buf, app, applen);
-  br_ssl_engine_recvapp_ack(&BACKEND->ctx.eng, applen);
+  br_ssl_engine_recvapp_ack(&backend->ctx.eng, applen);
 
   return applen;
 }
@@ -739,8 +743,8 @@ static bool Curl_bearssl_data_pending(const struct connectdata *conn,
                                       int connindex)
 {
   const struct ssl_connect_data *connssl = &conn->ssl[connindex];
-
-  return br_ssl_engine_current_state(&BACKEND->ctx.eng) & BR_SSL_RECVAPP;
+  struct ssl_backend_data *backend = connssl->backend;
+  return br_ssl_engine_current_state(&backend->ctx.eng) & BR_SSL_RECVAPP;
 }
 
 static CURLcode Curl_bearssl_random(struct Curl_easy *data UNUSED_PARAM,
@@ -786,21 +790,23 @@ static CURLcode Curl_bearssl_connect_nonblocking(struct connectdata *conn,
 static void *Curl_bearssl_get_internals(struct ssl_connect_data *connssl,
                                         CURLINFO info UNUSED_PARAM)
 {
-  return &BACKEND->ctx;
+  struct ssl_backend_data *backend = connssl->backend;
+  return &backend->ctx;
 }
 
 static void Curl_bearssl_close(struct connectdata *conn, int sockindex)
 {
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   size_t i;
 
-  if(BACKEND->active) {
-    br_ssl_engine_close(&BACKEND->ctx.eng);
+  if(backend->active) {
+    br_ssl_engine_close(&backend->ctx.eng);
     (void)bearssl_run_until(conn, sockindex, BR_SSL_CLOSED);
   }
-  for(i = 0; i < BACKEND->anchors_len; ++i)
-    free(BACKEND->anchors[i].dn.data);
-  free(BACKEND->anchors);
+  for(i = 0; i < backend->anchors_len; ++i)
+    free(backend->anchors[i].dn.data);
+  free(backend->anchors);
 }
 
 static void Curl_bearssl_session_free(void *ptr)
@@ -836,9 +842,7 @@ static CURLcode Curl_bearssl_sha256sum(const unsigned char *input,
 
 const struct Curl_ssl Curl_ssl_bearssl = {
   { CURLSSLBACKEND_BEARSSL, "bearssl" },
-
   0,
-
   sizeof(struct ssl_backend_data),
 
   Curl_none_init,
diff --git a/lib/vtls/gskit.c b/lib/vtls/gskit.c
index 32153dd0..b0864b5f 100644
--- a/lib/vtls/gskit.c
+++ b/lib/vtls/gskit.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -524,7 +524,6 @@ static int pipe_ssloverssl(struct connectdata *conn, int sockindex,
   int m;
   int i;
   int ret = 0;
-  struct timeval tv = {0, 0};
   char buf[CURL_MAX_WRITE_SIZE];
 
   if(!connssl->use || !connproxyssl->use)
@@ -544,7 +543,7 @@ static int pipe_ssloverssl(struct connectdata *conn, int sockindex,
     if(n < conn->sock[sockindex])
       n = conn->sock[sockindex];
   }
-  i = select(n + 1, &fds_read, &fds_write, NULL, &tv);
+  i = Curl_select(n + 1, &fds_read, &fds_write, NULL, 0);
   if(i < 0)
     return -1;  /* Select error. */
 
diff --git a/lib/vtls/gtls.c b/lib/vtls/gtls.c
index 5f740eeb..4ed3ea5c 100644
--- a/lib/vtls/gtls.c
+++ b/lib/vtls/gtls.c
@@ -72,36 +72,11 @@ static void tls_log_func(int level, const char *str)
 #endif
 static bool gtls_inited = FALSE;
 
-#if defined(GNUTLS_VERSION_NUMBER)
-#  if (GNUTLS_VERSION_NUMBER >= 0x020c00)
-#    undef gnutls_transport_set_lowat
-#    define gnutls_transport_set_lowat(A,B) Curl_nop_stmt
-#    define USE_GNUTLS_PRIORITY_SET_DIRECT 1
-#  endif
-#  if (GNUTLS_VERSION_NUMBER >= 0x020c03)
-#    define GNUTLS_MAPS_WINSOCK_ERRORS 1
-#  endif
-
-#  if HAVE_GNUTLS_ALPN_SET_PROTOCOLS
-#    define HAS_ALPN
-#  endif
-
-#  if HAVE_GNUTLS_OCSP_REQ_INIT
-#    define HAS_OCSP
-#  endif
-
-#  if (GNUTLS_VERSION_NUMBER >= 0x030306)
-#    define HAS_CAPATH
-#  endif
+#if !defined(GNUTLS_VERSION_NUMBER) || (GNUTLS_VERSION_NUMBER < 0x03010a)
+#error "too old GnuTLS version"
 #endif
 
-#if (GNUTLS_VERSION_NUMBER >= 0x030603)
-#define HAS_TLS13
-#endif
-
-#ifdef HAS_OCSP
 # include <gnutls/ocsp.h>
-#endif
 
 struct ssl_backend_data {
   gnutls_session_t session;
@@ -111,58 +86,10 @@ struct ssl_backend_data {
 #endif
 };
 
-#define BACKEND connssl->backend
-
-/*
- * Custom push and pull callback functions used by GNU TLS to read and write
- * to the socket.  These functions are simple wrappers to send() and recv()
- * (although here using the sread/swrite macros as defined by
- * curl_setup_once.h).
- * We use custom functions rather than the GNU TLS defaults because it allows
- * us to get specific about the fourth "flags" argument, and to use arbitrary
- * private data with gnutls_transport_set_ptr if we wish.
- *
- * When these custom push and pull callbacks fail, GNU TLS checks its own
- * session-specific error variable, and when not set also its own global
- * errno variable, in order to take appropriate action. GNU TLS does not
- * require that the transport is actually a socket. This implies that for
- * Windows builds these callbacks should ideally set the session-specific
- * error variable using function gnutls_transport_set_errno or as a last
- * resort global errno variable using gnutls_transport_set_global_errno,
- * with a transport agnostic error value. This implies that some winsock
- * error translation must take place in these callbacks.
- *
- * Paragraph above applies to GNU TLS versions older than 2.12.3, since
- * this version GNU TLS does its own internal winsock error translation
- * using system_errno() function.
- */
-
-#if defined(USE_WINSOCK) && !defined(GNUTLS_MAPS_WINSOCK_ERRORS)
-#  define gtls_EINTR  4
-#  define gtls_EIO    5
-#  define gtls_EAGAIN 11
-static int gtls_mapped_sockerrno(void)
-{
-  switch(SOCKERRNO) {
-  case WSAEWOULDBLOCK:
-    return gtls_EAGAIN;
-  case WSAEINTR:
-    return gtls_EINTR;
-  default:
-    break;
-  }
-  return gtls_EIO;
-}
-#endif
-
 static ssize_t Curl_gtls_push(void *s, const void *buf, size_t len)
 {
   curl_socket_t sock = *(curl_socket_t *)s;
   ssize_t ret = swrite(sock, buf, len);
-#if defined(USE_WINSOCK) && !defined(GNUTLS_MAPS_WINSOCK_ERRORS)
-  if(ret < 0)
-    gnutls_transport_set_global_errno(gtls_mapped_sockerrno());
-#endif
   return ret;
 }
 
@@ -170,10 +97,6 @@ static ssize_t Curl_gtls_pull(void *s, void *buf, size_t len)
 {
   curl_socket_t sock = *(curl_socket_t *)s;
   ssize_t ret = sread(sock, buf, len);
-#if defined(USE_WINSOCK) && !defined(GNUTLS_MAPS_WINSOCK_ERRORS)
-  if(ret < 0)
-    gnutls_transport_set_global_errno(gtls_mapped_sockerrno());
-#endif
   return ret;
 }
 
@@ -284,7 +207,8 @@ static CURLcode handshake(struct connectdata *conn,
 {
   struct Curl_easy *data = conn->data;
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
-  gnutls_session_t session = BACKEND->session;
+  struct ssl_backend_data *backend = connssl->backend;
+  gnutls_session_t session = backend->session;
   curl_socket_t sockfd = conn->sock[sockindex];
 
   for(;;) {
@@ -383,51 +307,6 @@ static gnutls_x509_crt_fmt_t do_file_type(const char *type)
   return -1;
 }
 
-#ifndef USE_GNUTLS_PRIORITY_SET_DIRECT
-static CURLcode
-set_ssl_version_min_max(int *list, size_t list_size, struct connectdata *conn)
-{
-  struct Curl_easy *data = conn->data;
-  long ssl_version = SSL_CONN_CONFIG(version);
-  long ssl_version_max = SSL_CONN_CONFIG(version_max);
-  long i = ssl_version;
-  long protocol_priority_idx = 0;
-
-  switch(ssl_version_max) {
-    case CURL_SSLVERSION_MAX_NONE:
-    case CURL_SSLVERSION_MAX_DEFAULT:
-#ifdef HAS_TLS13
-      ssl_version_max = CURL_SSLVERSION_MAX_TLSv1_3;
-#endif
-      ssl_version_max = CURL_SSLVERSION_MAX_TLSv1_2;
-      break;
-  }
-
-  for(; i <= (ssl_version_max >> 16) &&
-        protocol_priority_idx < list_size; ++i) {
-    switch(i) {
-      case CURL_SSLVERSION_TLSv1_0:
-        protocol_priority[protocol_priority_idx++] = GNUTLS_TLS1_0;
-        break;
-      case CURL_SSLVERSION_TLSv1_1:
-        protocol_priority[protocol_priority_idx++] = GNUTLS_TLS1_1;
-        break;
-      case CURL_SSLVERSION_TLSv1_2:
-        protocol_priority[protocol_priority_idx++] = GNUTLS_TLS1_2;
-        break;
-      case CURL_SSLVERSION_TLSv1_3:
-#ifdef HAS_TLS13
-        protocol_priority[protocol_priority_idx++] = GNUTLS_TLS1_3;
-        break;
-#else
-        failf(data, "GnuTLS: TLS 1.3 is not yet supported");
-        return CURLE_SSL_CONNECT_ERROR;
-#endif
-    }
-  }
-  return CURLE_OK;
-}
-#else
 #define GNUTLS_CIPHERS "NORMAL:-ARCFOUR-128:-CTYPE-ALL:+CTYPE-X509"
 /* If GnuTLS was compiled without support for SRP it will error out if SRP is
    requested in the priority string, so treat it specially
@@ -445,77 +324,59 @@ set_ssl_version_min_max(const char **prioritylist, struct connectdata *conn)
     ssl_version_max = CURL_SSLVERSION_MAX_DEFAULT;
   }
   switch(ssl_version | ssl_version_max) {
-    case CURL_SSLVERSION_TLSv1_0 | CURL_SSLVERSION_MAX_TLSv1_0:
-      *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
-                      "+VERS-TLS1.0:" GNUTLS_SRP;
-      return CURLE_OK;
-    case CURL_SSLVERSION_TLSv1_0 | CURL_SSLVERSION_MAX_TLSv1_1:
-      *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
-                      "+VERS-TLS1.0:+VERS-TLS1.1:" GNUTLS_SRP;
-      return CURLE_OK;
-    case CURL_SSLVERSION_TLSv1_0 | CURL_SSLVERSION_MAX_TLSv1_2:
-      *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
-                      "+VERS-TLS1.0:+VERS-TLS1.1:+VERS-TLS1.2:" GNUTLS_SRP;
-      return CURLE_OK;
-    case CURL_SSLVERSION_TLSv1_1 | CURL_SSLVERSION_MAX_TLSv1_1:
-      *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
-                      "+VERS-TLS1.1:" GNUTLS_SRP;
-      return CURLE_OK;
-    case CURL_SSLVERSION_TLSv1_1 | CURL_SSLVERSION_MAX_TLSv1_2:
-      *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
-                      "+VERS-TLS1.1:+VERS-TLS1.2:" GNUTLS_SRP;
-      return CURLE_OK;
-    case CURL_SSLVERSION_TLSv1_2 | CURL_SSLVERSION_MAX_TLSv1_2:
-      *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
-                      "+VERS-TLS1.2:" GNUTLS_SRP;
-      return CURLE_OK;
-    case CURL_SSLVERSION_TLSv1_3 | CURL_SSLVERSION_MAX_TLSv1_3:
-#ifdef HAS_TLS13
-       *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
-                       "+VERS-TLS1.3:" GNUTLS_SRP;
-      return CURLE_OK;
-#else
-       failf(data, "GnuTLS: TLS 1.3 is not yet supported");
-      return CURLE_SSL_CONNECT_ERROR;
-#endif
-    case CURL_SSLVERSION_TLSv1_0 | CURL_SSLVERSION_MAX_DEFAULT:
-      *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
-                      "+VERS-TLS1.0:+VERS-TLS1.1:+VERS-TLS1.2:"
-#ifdef HAS_TLS13
-                      "+VERS-TLS1.3:"
-#endif
-                      GNUTLS_SRP;
-      return CURLE_OK;
-    case CURL_SSLVERSION_TLSv1_1 | CURL_SSLVERSION_MAX_DEFAULT:
-      *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
-                      "+VERS-TLS1.1:+VERS-TLS1.2:"
-#ifdef HAS_TLS13
-                      "+VERS-TLS1.3:"
-#endif
-                      GNUTLS_SRP;
-      return CURLE_OK;
-    case CURL_SSLVERSION_TLSv1_2 | CURL_SSLVERSION_MAX_DEFAULT:
-      *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
-                      "+VERS-TLS1.2:"
-#ifdef HAS_TLS13
-                      "+VERS-TLS1.3:"
-#endif
-                      GNUTLS_SRP;
-      return CURLE_OK;
-    case CURL_SSLVERSION_TLSv1_3 | CURL_SSLVERSION_MAX_DEFAULT:
-      *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
-                      "+VERS-TLS1.2:"
-#ifdef HAS_TLS13
-                      "+VERS-TLS1.3:"
-#endif
-                      GNUTLS_SRP;
-      return CURLE_OK;
+  case CURL_SSLVERSION_TLSv1_0 | CURL_SSLVERSION_MAX_TLSv1_0:
+    *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
+      "+VERS-TLS1.0";
+    return CURLE_OK;
+  case CURL_SSLVERSION_TLSv1_0 | CURL_SSLVERSION_MAX_TLSv1_1:
+    *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
+      "+VERS-TLS1.0:+VERS-TLS1.1";
+    return CURLE_OK;
+  case CURL_SSLVERSION_TLSv1_0 | CURL_SSLVERSION_MAX_TLSv1_2:
+    *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
+      "+VERS-TLS1.0:+VERS-TLS1.1:+VERS-TLS1.2";
+    return CURLE_OK;
+  case CURL_SSLVERSION_TLSv1_1 | CURL_SSLVERSION_MAX_TLSv1_1:
+    *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
+      "+VERS-TLS1.1";
+    return CURLE_OK;
+  case CURL_SSLVERSION_TLSv1_1 | CURL_SSLVERSION_MAX_TLSv1_2:
+    *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
+      "+VERS-TLS1.1:+VERS-TLS1.2";
+    return CURLE_OK;
+  case CURL_SSLVERSION_TLSv1_2 | CURL_SSLVERSION_MAX_TLSv1_2:
+    *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
+      "+VERS-TLS1.2";
+    return CURLE_OK;
+  case CURL_SSLVERSION_TLSv1_3 | CURL_SSLVERSION_MAX_TLSv1_3:
+    *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
+      "+VERS-TLS1.3";
+    return CURLE_OK;
+  case CURL_SSLVERSION_TLSv1_0 | CURL_SSLVERSION_MAX_DEFAULT:
+    *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
+      "+VERS-TLS1.0:+VERS-TLS1.1:+VERS-TLS1.2"
+      ":+VERS-TLS1.3";
+    return CURLE_OK;
+  case CURL_SSLVERSION_TLSv1_1 | CURL_SSLVERSION_MAX_DEFAULT:
+    *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
+      "+VERS-TLS1.1:+VERS-TLS1.2"
+      ":+VERS-TLS1.3";
+    return CURLE_OK;
+  case CURL_SSLVERSION_TLSv1_2 | CURL_SSLVERSION_MAX_DEFAULT:
+    *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
+      "+VERS-TLS1.2"
+      ":+VERS-TLS1.3";
+    return CURLE_OK;
+  case CURL_SSLVERSION_TLSv1_3 | CURL_SSLVERSION_MAX_DEFAULT:
+    *prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:-VERS-TLS-ALL:"
+      "+VERS-TLS1.2"
+      ":+VERS-TLS1.3";
+    return CURLE_OK;
   }
 
   failf(data, "GnuTLS: cannot set ssl protocol");
   return CURLE_SSL_CONNECT_ERROR;
 }
-#endif
 
 static CURLcode
 gtls_connect_step1(struct connectdata *conn,
@@ -523,6 +384,7 @@ gtls_connect_step1(struct connectdata *conn,
 {
   struct Curl_easy *data = conn->data;
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   unsigned int init_flags;
   gnutls_session_t session;
   int rc;
@@ -535,26 +397,8 @@ gtls_connect_step1(struct connectdata *conn,
 #else
   struct in_addr addr;
 #endif
-#ifndef USE_GNUTLS_PRIORITY_SET_DIRECT
-  static const int cipher_priority[] = {
-  /* These two ciphers were added to GnuTLS as late as ver. 3.0.1,
-     but this code path is only ever used for ver. < 2.12.0.
-     GNUTLS_CIPHER_AES_128_GCM,
-     GNUTLS_CIPHER_AES_256_GCM,
-  */
-    GNUTLS_CIPHER_AES_128_CBC,
-    GNUTLS_CIPHER_AES_256_CBC,
-    GNUTLS_CIPHER_CAMELLIA_128_CBC,
-    GNUTLS_CIPHER_CAMELLIA_256_CBC,
-    GNUTLS_CIPHER_3DES_CBC,
-  };
-  static const int cert_type_priority[] = { GNUTLS_CRT_X509, 0 };
-  int protocol_priority[] = { 0, 0, 0, 0 };
-#else
   const char *prioritylist;
   const char *err = NULL;
-#endif
-
   const char * const hostname = SSL_IS_PROXY() ? conn->http_proxy.host.name :
     conn->host.name;
 
@@ -574,7 +418,7 @@ gtls_connect_step1(struct connectdata *conn,
     sni = FALSE; /* SSLv3 has no SNI */
 
   /* allocate a cred struct */
-  rc = gnutls_certificate_allocate_credentials(&BACKEND->cred);
+  rc = gnutls_certificate_allocate_credentials(&backend->cred);
   if(rc != GNUTLS_E_SUCCESS) {
     failf(data, "gnutls_cert_all_cred() failed: %s", gnutls_strerror(rc));
     return CURLE_SSL_CONNECT_ERROR;
@@ -585,14 +429,14 @@ gtls_connect_step1(struct connectdata *conn,
     infof(data, "Using TLS-SRP username: %s\n", SSL_SET_OPTION(username));
 
     rc = gnutls_srp_allocate_client_credentials(
-           &BACKEND->srp_client_cred);
+           &backend->srp_client_cred);
     if(rc != GNUTLS_E_SUCCESS) {
       failf(data, "gnutls_srp_allocate_client_cred() failed: %s",
             gnutls_strerror(rc));
       return CURLE_OUT_OF_MEMORY;
     }
 
-    rc = gnutls_srp_set_client_credentials(BACKEND->srp_client_cred,
+    rc = gnutls_srp_set_client_credentials(backend->srp_client_cred,
                                            SSL_SET_OPTION(username),
                                            SSL_SET_OPTION(password));
     if(rc != GNUTLS_E_SUCCESS) {
@@ -605,10 +449,10 @@ gtls_connect_step1(struct connectdata *conn,
 
   if(SSL_CONN_CONFIG(CAfile)) {
     /* set the trusted CA cert bundle file */
-    gnutls_certificate_set_verify_flags(BACKEND->cred,
+    gnutls_certificate_set_verify_flags(backend->cred,
                                         GNUTLS_VERIFY_ALLOW_X509_V1_CA_CRT);
 
-    rc = gnutls_certificate_set_x509_trust_file(BACKEND->cred,
+    rc = gnutls_certificate_set_x509_trust_file(backend->cred,
                                                 SSL_CONN_CONFIG(CAfile),
                                                 GNUTLS_X509_FMT_PEM);
     if(rc < 0) {
@@ -622,10 +466,9 @@ gtls_connect_step1(struct connectdata *conn,
             SSL_CONN_CONFIG(CAfile));
   }
 
-#ifdef HAS_CAPATH
   if(SSL_CONN_CONFIG(CApath)) {
     /* set the trusted CA cert directory */
-    rc = gnutls_certificate_set_x509_trust_dir(BACKEND->cred,
+    rc = gnutls_certificate_set_x509_trust_dir(backend->cred,
                                                SSL_CONN_CONFIG(CApath),
                                                GNUTLS_X509_FMT_PEM);
     if(rc < 0) {
@@ -638,19 +481,18 @@ gtls_connect_step1(struct connectdata *conn,
       infof(data, "found %d certificates in %s\n",
             rc, SSL_CONN_CONFIG(CApath));
   }
-#endif
 
 #ifdef CURL_CA_FALLBACK
   /* use system ca certificate store as fallback */
   if(SSL_CONN_CONFIG(verifypeer) &&
      !(SSL_CONN_CONFIG(CAfile) || SSL_CONN_CONFIG(CApath))) {
-    gnutls_certificate_set_x509_system_trust(BACKEND->cred);
+    gnutls_certificate_set_x509_system_trust(backend->cred);
   }
 #endif
 
   if(SSL_SET_OPTION(CRLfile)) {
     /* set the CRL list file */
-    rc = gnutls_certificate_set_x509_crl_file(BACKEND->cred,
+    rc = gnutls_certificate_set_x509_crl_file(backend->cred,
                                               SSL_SET_OPTION(CRLfile),
                                               GNUTLS_X509_FMT_PEM);
     if(rc < 0) {
@@ -675,14 +517,14 @@ gtls_connect_step1(struct connectdata *conn,
   init_flags |= GNUTLS_NO_TICKETS;
 #endif
 
-  rc = gnutls_init(&BACKEND->session, init_flags);
+  rc = gnutls_init(&backend->session, init_flags);
   if(rc != GNUTLS_E_SUCCESS) {
     failf(data, "gnutls_init() failed: %d", rc);
     return CURLE_SSL_CONNECT_ERROR;
   }
 
   /* convenient assign */
-  session = BACKEND->session;
+  session = backend->session;
 
   if((0 == Curl_inet_pton(AF_INET, hostname, &addr)) &&
 #ifdef ENABLE_IPV6
@@ -699,62 +541,6 @@ gtls_connect_step1(struct connectdata *conn,
   if(rc != GNUTLS_E_SUCCESS)
     return CURLE_SSL_CONNECT_ERROR;
 
-#ifndef USE_GNUTLS_PRIORITY_SET_DIRECT
-  rc = gnutls_cipher_set_priority(session, cipher_priority);
-  if(rc != GNUTLS_E_SUCCESS)
-    return CURLE_SSL_CONNECT_ERROR;
-
-  /* Sets the priority on the certificate types supported by gnutls. Priority
-   is higher for types specified before others. After specifying the types
-   you want, you must append a 0. */
-  rc = gnutls_certificate_type_set_priority(session, cert_type_priority);
-  if(rc != GNUTLS_E_SUCCESS)
-    return CURLE_SSL_CONNECT_ERROR;
-
-  if(SSL_CONN_CONFIG(cipher_list) != NULL) {
-    failf(data, "can't pass a custom cipher list to older GnuTLS"
-          " versions");
-    return CURLE_SSL_CONNECT_ERROR;
-  }
-
-  switch(SSL_CONN_CONFIG(version)) {
-    case CURL_SSLVERSION_SSLv3:
-      protocol_priority[0] = GNUTLS_SSL3;
-      break;
-    case CURL_SSLVERSION_DEFAULT:
-    case CURL_SSLVERSION_TLSv1:
-      protocol_priority[0] = GNUTLS_TLS1_0;
-      protocol_priority[1] = GNUTLS_TLS1_1;
-      protocol_priority[2] = GNUTLS_TLS1_2;
-#ifdef HAS_TLS13
-      protocol_priority[3] = GNUTLS_TLS1_3;
-#endif
-      break;
-    case CURL_SSLVERSION_TLSv1_0:
-    case CURL_SSLVERSION_TLSv1_1:
-    case CURL_SSLVERSION_TLSv1_2:
-    case CURL_SSLVERSION_TLSv1_3:
-      {
-        CURLcode result = set_ssl_version_min_max(protocol_priority,
-                sizeof(protocol_priority)/sizeof(protocol_priority[0]), conn);
-        if(result != CURLE_OK)
-          return result;
-        break;
-      }
-    case CURL_SSLVERSION_SSLv2:
-      failf(data, "GnuTLS does not support SSLv2");
-      return CURLE_SSL_CONNECT_ERROR;
-    default:
-      failf(data, "Unrecognized parameter passed via CURLOPT_SSLVERSION");
-      return CURLE_SSL_CONNECT_ERROR;
-  }
-  rc = gnutls_protocol_set_priority(session, protocol_priority);
-  if(rc != GNUTLS_E_SUCCESS) {
-    failf(data, "Did you pass a valid GnuTLS cipher list?");
-    return CURLE_SSL_CONNECT_ERROR;
-  }
-
-#else
   /* Ensure +SRP comes at the *end* of all relevant strings so that it can be
    * removed if a run-time error indicates that SRP is not supported by this
    * GnuTLS version */
@@ -764,11 +550,11 @@ gtls_connect_step1(struct connectdata *conn,
       break;
     case CURL_SSLVERSION_DEFAULT:
     case CURL_SSLVERSION_TLSv1:
-      prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0:"
+      prioritylist = GNUTLS_CIPHERS ":-VERS-SSL3.0"
 #ifdef HAS_TLS13
-                     "+VERS-TLS1.3:"
+                     ":+VERS-TLS1.3"
 #endif
-                     GNUTLS_SRP;
+                     ;
       break;
     case CURL_SSLVERSION_TLSv1_0:
     case CURL_SSLVERSION_TLSv1_1:
@@ -787,32 +573,39 @@ gtls_connect_step1(struct connectdata *conn,
       failf(data, "Unrecognized parameter passed via CURLOPT_SSLVERSION");
       return CURLE_SSL_CONNECT_ERROR;
   }
-  rc = gnutls_priority_set_direct(session, prioritylist, &err);
-  if((rc == GNUTLS_E_INVALID_REQUEST) && err) {
-    if(!strcmp(err, GNUTLS_SRP)) {
-      /* This GnuTLS was probably compiled without support for SRP.
-       * Note that fact and try again without it. */
-      int validprioritylen = curlx_uztosi(err - prioritylist);
-      char *prioritycopy = strdup(prioritylist);
-      if(!prioritycopy)
-        return CURLE_OUT_OF_MEMORY;
 
+#ifdef USE_TLS_SRP
+  /* Only add SRP to the cipher list if SRP is requested. Otherwise
+   * GnuTLS will disable TLS 1.3 support. */
+  if(SSL_SET_OPTION(authtype) == CURL_TLSAUTH_SRP) {
+    size_t len = strlen(prioritylist);
+
+    char *prioritysrp = malloc(len + sizeof(GNUTLS_SRP) + 1);
+    if(!prioritysrp)
+      return CURLE_OUT_OF_MEMORY;
+    strcpy(prioritysrp, prioritylist);
+    strcpy(prioritysrp + len, ":" GNUTLS_SRP);
+
+    rc = gnutls_priority_set_direct(session, prioritysrp, &err);
+    free(prioritysrp);
+
+    if((rc == GNUTLS_E_INVALID_REQUEST) && err) {
       infof(data, "This GnuTLS does not support SRP\n");
-      if(validprioritylen)
-        /* Remove the :+SRP */
-        prioritycopy[validprioritylen - 1] = 0;
-      rc = gnutls_priority_set_direct(session, prioritycopy, &err);
-      free(prioritycopy);
     }
   }
+  else {
+#endif
+    rc = gnutls_priority_set_direct(session, prioritylist, &err);
+#ifdef USE_TLS_SRP
+  }
+#endif
+
   if(rc != GNUTLS_E_SUCCESS) {
     failf(data, "Error %d setting GnuTLS cipher list starting with %s",
           rc, err);
     return CURLE_SSL_CONNECT_ERROR;
   }
-#endif
 
-#ifdef HAS_ALPN
   if(conn->bits.tls_enable_alpn) {
     int cur = 0;
     gnutls_datum_t protocols[2];
@@ -834,18 +627,16 @@ gtls_connect_step1(struct connectdata *conn,
 
     gnutls_alpn_set_protocols(session, protocols, cur, 0);
   }
-#endif
 
   if(SSL_SET_OPTION(cert)) {
     if(SSL_SET_OPTION(key_passwd)) {
-#if HAVE_GNUTLS_CERTIFICATE_SET_X509_KEY_FILE2
       const unsigned int supported_key_encryption_algorithms =
         GNUTLS_PKCS_USE_PKCS12_3DES | GNUTLS_PKCS_USE_PKCS12_ARCFOUR |
         GNUTLS_PKCS_USE_PKCS12_RC2_40 | GNUTLS_PKCS_USE_PBES2_3DES |
         GNUTLS_PKCS_USE_PBES2_AES_128 | GNUTLS_PKCS_USE_PBES2_AES_192 |
         GNUTLS_PKCS_USE_PBES2_AES_256;
       rc = gnutls_certificate_set_x509_key_file2(
-           BACKEND->cred,
+           backend->cred,
            SSL_SET_OPTION(cert),
            SSL_SET_OPTION(key) ?
            SSL_SET_OPTION(key) : SSL_SET_OPTION(cert),
@@ -858,14 +649,10 @@ gtls_connect_step1(struct connectdata *conn,
               gnutls_strerror(rc));
         return CURLE_SSL_CONNECT_ERROR;
       }
-#else
-      failf(data, "gnutls lacks support for encrypted key files");
-      return CURLE_SSL_CONNECT_ERROR;
-#endif
     }
     else {
       if(gnutls_certificate_set_x509_key_file(
-           BACKEND->cred,
+           backend->cred,
            SSL_SET_OPTION(cert),
            SSL_SET_OPTION(key) ?
            SSL_SET_OPTION(key) : SSL_SET_OPTION(cert),
@@ -881,7 +668,7 @@ gtls_connect_step1(struct connectdata *conn,
   /* put the credentials to the current session */
   if(SSL_SET_OPTION(authtype) == CURL_TLSAUTH_SRP) {
     rc = gnutls_credentials_set(session, GNUTLS_CRD_SRP,
-                                BACKEND->srp_client_cred);
+                                backend->srp_client_cred);
     if(rc != GNUTLS_E_SUCCESS) {
       failf(data, "gnutls_credentials_set() failed: %s", gnutls_strerror(rc));
       return CURLE_SSL_CONNECT_ERROR;
@@ -891,7 +678,7 @@ gtls_connect_step1(struct connectdata *conn,
 #endif
   {
     rc = gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE,
-                                BACKEND->cred);
+                                backend->cred);
     if(rc != GNUTLS_E_SUCCESS) {
       failf(data, "gnutls_credentials_set() failed: %s", gnutls_strerror(rc));
       return CURLE_SSL_CONNECT_ERROR;
@@ -917,10 +704,6 @@ gtls_connect_step1(struct connectdata *conn,
   gnutls_transport_set_push_function(session, gnutls_transport_push);
   gnutls_transport_set_pull_function(session, gnutls_transport_pull);
 
-  /* lowat must be set to zero when using custom push and pull functions. */
-  gnutls_transport_set_lowat(session, 0);
-
-#ifdef HAS_OCSP
   if(SSL_CONN_CONFIG(verifystatus)) {
     rc = gnutls_ocsp_status_request_enable_client(session, NULL, 0, NULL);
     if(rc != GNUTLS_E_SUCCESS) {
@@ -928,7 +711,6 @@ gtls_connect_step1(struct connectdata *conn,
       return CURLE_SSL_CONNECT_ERROR;
     }
   }
-#endif
 
   /* This might be a reconnect, so we check for a session ID in the cache
      to speed up things */
@@ -1020,17 +802,17 @@ gtls_connect_step3(struct connectdata *conn,
   unsigned int verify_status = 0;
   gnutls_x509_crt_t x509_cert, x509_issuer;
   gnutls_datum_t issuerp;
-  char certbuf[256] = ""; /* big enough? */
+  gnutls_datum_t certfields;
+  char certname[65] = ""; /* limited to 64 chars by ASN.1 */
   size_t size;
   time_t certclock;
   const char *ptr;
   struct Curl_easy *data = conn->data;
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
-  gnutls_session_t session = BACKEND->session;
+  struct ssl_backend_data *backend = connssl->backend;
+  gnutls_session_t session = backend->session;
   int rc;
-#ifdef HAS_ALPN
   gnutls_datum_t proto;
-#endif
   CURLcode result = CURLE_OK;
 #ifndef CURL_DISABLE_VERBOSE_STRINGS
   unsigned int algo;
@@ -1127,7 +909,6 @@ gtls_connect_step3(struct connectdata *conn,
   else
     infof(data, "\t server certificate verification SKIPPED\n");
 
-#ifdef HAS_OCSP
   if(SSL_CONN_CONFIG(verifystatus)) {
     if(gnutls_ocsp_status_request_is_checked(session, 0) == 0) {
       gnutls_datum_t status_request;
@@ -1230,7 +1011,6 @@ gtls_connect_step3(struct connectdata *conn,
   }
   else
     infof(data, "\t server certificate status verification SKIPPED\n");
-#endif
 
   /* initialize an X.509 certificate structure. */
   gnutls_x509_crt_init(&x509_cert);
@@ -1257,11 +1037,11 @@ gtls_connect_step3(struct connectdata *conn,
           SSL_SET_OPTION(issuercert)?SSL_SET_OPTION(issuercert):"none");
   }
 
-  size = sizeof(certbuf);
+  size = sizeof(certname);
   rc = gnutls_x509_crt_get_dn_by_oid(x509_cert, GNUTLS_OID_X520_COMMON_NAME,
                                      0, /* the first and only one */
                                      FALSE,
-                                     certbuf,
+                                     certname,
                                      &size);
   if(rc) {
     infof(data, "error fetching CN from cert:%s\n",
@@ -1322,16 +1102,16 @@ gtls_connect_step3(struct connectdata *conn,
 
     if(SSL_CONN_CONFIG(verifyhost)) {
       failf(data, "SSL: certificate subject name (%s) does not match "
-            "target host name '%s'", certbuf, dispname);
+            "target host name '%s'", certname, dispname);
       gnutls_x509_crt_deinit(x509_cert);
       return CURLE_PEER_FAILED_VERIFICATION;
     }
     else
       infof(data, "\t common name: %s (does not match '%s')\n",
-            certbuf, dispname);
+            certname, dispname);
   }
   else
-    infof(data, "\t common name: %s (matched)\n", certbuf);
+    infof(data, "\t common name: %s (matched)\n", certname);
 
   /* Check for time-based validity */
   certclock = gnutls_x509_crt_get_expiration_time(x509_cert);
@@ -1416,9 +1196,10 @@ gtls_connect_step3(struct connectdata *conn,
         gnutls_x509_crt_get_version(x509_cert));
 
 
-  size = sizeof(certbuf);
-  gnutls_x509_crt_get_dn(x509_cert, certbuf, &size);
-  infof(data, "\t subject: %s\n", certbuf);
+  rc = gnutls_x509_crt_get_dn2(x509_cert, &certfields);
+  if(rc != 0)
+    return CURLE_OUT_OF_MEMORY;
+  infof(data, "\t subject: %s\n", certfields.data);
 
   certclock = gnutls_x509_crt_get_activation_time(x509_cert);
   showtime(data, "start date", certclock);
@@ -1426,14 +1207,14 @@ gtls_connect_step3(struct connectdata *conn,
   certclock = gnutls_x509_crt_get_expiration_time(x509_cert);
   showtime(data, "expire date", certclock);
 
-  size = sizeof(certbuf);
-  gnutls_x509_crt_get_issuer_dn(x509_cert, certbuf, &size);
-  infof(data, "\t issuer: %s\n", certbuf);
+  rc = gnutls_x509_crt_get_issuer_dn2(x509_cert, &certfields);
+  if(rc != 0)
+    return CURLE_OUT_OF_MEMORY;
+  infof(data, "\t issuer: %s\n", certfields.data);
 #endif
 
   gnutls_x509_crt_deinit(x509_cert);
 
-#ifdef HAS_ALPN
   if(conn->bits.tls_enable_alpn) {
     rc = gnutls_alpn_get_selected_protocol(session, &proto);
     if(rc == 0) {
@@ -1459,7 +1240,6 @@ gtls_connect_step3(struct connectdata *conn,
     Curl_multiuse_state(conn, conn->negnpn == CURL_HTTP_VERSION_2 ?
                         BUNDLE_MULTIPLEX : BUNDLE_NO_MULTIUSE);
   }
-#endif
 
   conn->ssl[sockindex].state = ssl_connection_complete;
   conn->recv[sockindex] = gtls_recv;
@@ -1577,13 +1357,14 @@ static bool Curl_gtls_data_pending(const struct connectdata *conn,
 {
   const struct ssl_connect_data *connssl = &conn->ssl[connindex];
   bool res = FALSE;
-  if(BACKEND->session &&
-     0 != gnutls_record_check_pending(BACKEND->session))
+  struct ssl_backend_data *backend = connssl->backend;
+  if(backend->session &&
+     0 != gnutls_record_check_pending(backend->session))
     res = TRUE;
 
   connssl = &conn->proxy_ssl[connindex];
-  if(BACKEND->session &&
-     0 != gnutls_record_check_pending(BACKEND->session))
+  if(backend->session &&
+     0 != gnutls_record_check_pending(backend->session))
     res = TRUE;
 
   return res;
@@ -1596,7 +1377,8 @@ static ssize_t gtls_send(struct connectdata *conn,
                          CURLcode *curlcode)
 {
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
-  ssize_t rc = gnutls_record_send(BACKEND->session, mem, len);
+  struct ssl_backend_data *backend = connssl->backend;
+  ssize_t rc = gnutls_record_send(backend->session, mem, len);
 
   if(rc < 0) {
     *curlcode = (rc == GNUTLS_E_AGAIN)
@@ -1611,19 +1393,20 @@ static ssize_t gtls_send(struct connectdata *conn,
 
 static void close_one(struct ssl_connect_data *connssl)
 {
-  if(BACKEND->session) {
-    gnutls_bye(BACKEND->session, GNUTLS_SHUT_WR);
-    gnutls_deinit(BACKEND->session);
-    BACKEND->session = NULL;
+  struct ssl_backend_data *backend = connssl->backend;
+  if(backend->session) {
+    gnutls_bye(backend->session, GNUTLS_SHUT_WR);
+    gnutls_deinit(backend->session);
+    backend->session = NULL;
   }
-  if(BACKEND->cred) {
-    gnutls_certificate_free_credentials(BACKEND->cred);
-    BACKEND->cred = NULL;
+  if(backend->cred) {
+    gnutls_certificate_free_credentials(backend->cred);
+    backend->cred = NULL;
   }
 #ifdef USE_TLS_SRP
-  if(BACKEND->srp_client_cred) {
-    gnutls_srp_free_client_credentials(BACKEND->srp_client_cred);
-    BACKEND->srp_client_cred = NULL;
+  if(backend->srp_client_cred) {
+    gnutls_srp_free_client_credentials(backend->srp_client_cred);
+    backend->srp_client_cred = NULL;
   }
 #endif
 }
@@ -1641,6 +1424,7 @@ static void Curl_gtls_close(struct connectdata *conn, int sockindex)
 static int Curl_gtls_shutdown(struct connectdata *conn, int sockindex)
 {
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   int retval = 0;
   struct Curl_easy *data = conn->data;
 
@@ -1651,10 +1435,10 @@ static int Curl_gtls_shutdown(struct connectdata *conn, int sockindex)
      we do not send one. Let's hope other servers do the same... */
 
   if(data->set.ftp_ccc == CURLFTPSSL_CCC_ACTIVE)
-      gnutls_bye(BACKEND->session, GNUTLS_SHUT_WR);
+    gnutls_bye(backend->session, GNUTLS_SHUT_WR);
 #endif
 
-  if(BACKEND->session) {
+  if(backend->session) {
     ssize_t result;
     bool done = FALSE;
     char buf[120];
@@ -1665,7 +1449,7 @@ static int Curl_gtls_shutdown(struct connectdata *conn, int sockindex)
       if(what > 0) {
         /* Something to read, let's do it and hope that it is the close
            notify alert from the server */
-        result = gnutls_record_recv(BACKEND->session,
+        result = gnutls_record_recv(backend->session,
                                     buf, sizeof(buf));
         switch(result) {
         case 0:
@@ -1695,18 +1479,18 @@ static int Curl_gtls_shutdown(struct connectdata *conn, int sockindex)
         done = TRUE;
       }
     }
-    gnutls_deinit(BACKEND->session);
+    gnutls_deinit(backend->session);
   }
-  gnutls_certificate_free_credentials(BACKEND->cred);
+  gnutls_certificate_free_credentials(backend->cred);
 
 #ifdef USE_TLS_SRP
   if(SSL_SET_OPTION(authtype) == CURL_TLSAUTH_SRP
      && SSL_SET_OPTION(username) != NULL)
-    gnutls_srp_free_client_credentials(BACKEND->srp_client_cred);
+    gnutls_srp_free_client_credentials(backend->srp_client_cred);
 #endif
 
-  BACKEND->cred = NULL;
-  BACKEND->session = NULL;
+  backend->cred = NULL;
+  backend->session = NULL;
 
   return retval;
 }
@@ -1718,9 +1502,10 @@ static ssize_t gtls_recv(struct connectdata *conn, /* connection data */
                          CURLcode *curlcode)
 {
   struct ssl_connect_data *connssl = &conn->ssl[num];
+  struct ssl_backend_data *backend = connssl->backend;
   ssize_t ret;
 
-  ret = gnutls_record_recv(BACKEND->session, buf, buffersize);
+  ret = gnutls_record_recv(backend->session, buf, buffersize);
   if((ret == GNUTLS_E_AGAIN) || (ret == GNUTLS_E_INTERRUPTED)) {
     *curlcode = CURLE_AGAIN;
     return -1;
@@ -1836,18 +1621,15 @@ static CURLcode Curl_gtls_sha256sum(const unsigned char *tmp, /* input */
 
 static bool Curl_gtls_cert_status_request(void)
 {
-#ifdef HAS_OCSP
   return TRUE;
-#else
-  return FALSE;
-#endif
 }
 
 static void *Curl_gtls_get_internals(struct ssl_connect_data *connssl,
                                      CURLINFO info UNUSED_PARAM)
 {
+  struct ssl_backend_data *backend = connssl->backend;
   (void)info;
-  return BACKEND->session;
+  return backend->session;
 }
 
 const struct Curl_ssl Curl_ssl_gnutls = {
diff --git a/lib/vtls/mbedtls.c b/lib/vtls/mbedtls.c
index f057315f..cbf3d3de 100644
--- a/lib/vtls/mbedtls.c
+++ b/lib/vtls/mbedtls.c
@@ -75,8 +75,6 @@ struct ssl_backend_data {
   const char *protocols[3];
 };
 
-#define BACKEND connssl->backend
-
 /* apply threading? */
 #if defined(USE_THREADS_POSIX) || defined(USE_THREADS_WIN32)
 #define THREADING_SUPPORT
@@ -196,6 +194,7 @@ set_ssl_version_min_max(struct connectdata *conn, int sockindex)
 {
   struct Curl_easy *data = conn->data;
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   int mbedtls_ver_min = MBEDTLS_SSL_MINOR_VERSION_1;
   int mbedtls_ver_max = MBEDTLS_SSL_MINOR_VERSION_1;
   long ssl_version = SSL_CONN_CONFIG(version);
@@ -227,9 +226,9 @@ set_ssl_version_min_max(struct connectdata *conn, int sockindex)
     return result;
   }
 
-  mbedtls_ssl_conf_min_version(&BACKEND->config, MBEDTLS_SSL_MAJOR_VERSION_3,
+  mbedtls_ssl_conf_min_version(&backend->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                mbedtls_ver_min);
-  mbedtls_ssl_conf_max_version(&BACKEND->config, MBEDTLS_SSL_MAJOR_VERSION_3,
+  mbedtls_ssl_conf_max_version(&backend->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                mbedtls_ver_max);
 
   return result;
@@ -241,6 +240,7 @@ mbed_connect_step1(struct connectdata *conn,
 {
   struct Curl_easy *data = conn->data;
   struct ssl_connect_data* connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   const char * const ssl_cafile = SSL_CONN_CONFIG(CAfile);
   const bool verifypeer = SSL_CONN_CONFIG(verifypeer);
   const char * const ssl_capath = SSL_CONN_CONFIG(CApath);
@@ -261,9 +261,9 @@ mbed_connect_step1(struct connectdata *conn,
 
 #ifdef THREADING_SUPPORT
   entropy_init_mutex(&ts_entropy);
-  mbedtls_ctr_drbg_init(&BACKEND->ctr_drbg);
+  mbedtls_ctr_drbg_init(&backend->ctr_drbg);
 
-  ret = mbedtls_ctr_drbg_seed(&BACKEND->ctr_drbg, entropy_func_mutex,
+  ret = mbedtls_ctr_drbg_seed(&backend->ctr_drbg, entropy_func_mutex,
                               &ts_entropy, NULL, 0);
   if(ret) {
 #ifdef MBEDTLS_ERROR_C
@@ -273,11 +273,11 @@ mbed_connect_step1(struct connectdata *conn,
           -ret, errorbuf);
   }
 #else
-  mbedtls_entropy_init(&BACKEND->entropy);
-  mbedtls_ctr_drbg_init(&BACKEND->ctr_drbg);
+  mbedtls_entropy_init(&backend->entropy);
+  mbedtls_ctr_drbg_init(&backend->ctr_drbg);
 
-  ret = mbedtls_ctr_drbg_seed(&BACKEND->ctr_drbg, mbedtls_entropy_func,
-                              &BACKEND->entropy, NULL, 0);
+  ret = mbedtls_ctr_drbg_seed(&backend->ctr_drbg, mbedtls_entropy_func,
+                              &backend->entropy, NULL, 0);
   if(ret) {
 #ifdef MBEDTLS_ERROR_C
     mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
@@ -288,10 +288,10 @@ mbed_connect_step1(struct connectdata *conn,
 #endif /* THREADING_SUPPORT */
 
   /* Load the trusted CA */
-  mbedtls_x509_crt_init(&BACKEND->cacert);
+  mbedtls_x509_crt_init(&backend->cacert);
 
   if(ssl_cafile) {
-    ret = mbedtls_x509_crt_parse_file(&BACKEND->cacert, ssl_cafile);
+    ret = mbedtls_x509_crt_parse_file(&backend->cacert, ssl_cafile);
 
     if(ret<0) {
 #ifdef MBEDTLS_ERROR_C
@@ -306,7 +306,7 @@ mbed_connect_step1(struct connectdata *conn,
   }
 
   if(ssl_capath) {
-    ret = mbedtls_x509_crt_parse_path(&BACKEND->cacert, ssl_capath);
+    ret = mbedtls_x509_crt_parse_path(&backend->cacert, ssl_capath);
 
     if(ret<0) {
 #ifdef MBEDTLS_ERROR_C
@@ -321,10 +321,10 @@ mbed_connect_step1(struct connectdata *conn,
   }
 
   /* Load the client certificate */
-  mbedtls_x509_crt_init(&BACKEND->clicert);
+  mbedtls_x509_crt_init(&backend->clicert);
 
   if(ssl_cert) {
-    ret = mbedtls_x509_crt_parse_file(&BACKEND->clicert, ssl_cert);
+    ret = mbedtls_x509_crt_parse_file(&backend->clicert, ssl_cert);
 
     if(ret) {
 #ifdef MBEDTLS_ERROR_C
@@ -338,13 +338,13 @@ mbed_connect_step1(struct connectdata *conn,
   }
 
   /* Load the client private key */
-  mbedtls_pk_init(&BACKEND->pk);
+  mbedtls_pk_init(&backend->pk);
 
   if(SSL_SET_OPTION(key)) {
-    ret = mbedtls_pk_parse_keyfile(&BACKEND->pk, SSL_SET_OPTION(key),
+    ret = mbedtls_pk_parse_keyfile(&backend->pk, SSL_SET_OPTION(key),
                                    SSL_SET_OPTION(key_passwd));
-    if(ret == 0 && !(mbedtls_pk_can_do(&BACKEND->pk, MBEDTLS_PK_RSA) ||
-                     mbedtls_pk_can_do(&BACKEND->pk, MBEDTLS_PK_ECKEY)))
+    if(ret == 0 && !(mbedtls_pk_can_do(&backend->pk, MBEDTLS_PK_RSA) ||
+                     mbedtls_pk_can_do(&backend->pk, MBEDTLS_PK_ECKEY)))
       ret = MBEDTLS_ERR_PK_TYPE_MISMATCH;
 
     if(ret) {
@@ -359,10 +359,10 @@ mbed_connect_step1(struct connectdata *conn,
   }
 
   /* Load the CRL */
-  mbedtls_x509_crl_init(&BACKEND->crl);
+  mbedtls_x509_crl_init(&backend->crl);
 
   if(ssl_crlfile) {
-    ret = mbedtls_x509_crl_parse_file(&BACKEND->crl, ssl_crlfile);
+    ret = mbedtls_x509_crl_parse_file(&backend->crl, ssl_crlfile);
 
     if(ret) {
 #ifdef MBEDTLS_ERROR_C
@@ -377,14 +377,14 @@ mbed_connect_step1(struct connectdata *conn,
 
   infof(data, "mbedTLS: Connecting to %s:%ld\n", hostname, port);
 
-  mbedtls_ssl_config_init(&BACKEND->config);
+  mbedtls_ssl_config_init(&backend->config);
 
-  mbedtls_ssl_init(&BACKEND->ssl);
-  if(mbedtls_ssl_setup(&BACKEND->ssl, &BACKEND->config)) {
+  mbedtls_ssl_init(&backend->ssl);
+  if(mbedtls_ssl_setup(&backend->ssl, &backend->config)) {
     failf(data, "mbedTLS: ssl_init failed");
     return CURLE_SSL_CONNECT_ERROR;
   }
-  ret = mbedtls_ssl_config_defaults(&BACKEND->config,
+  ret = mbedtls_ssl_config_defaults(&backend->config,
                                     MBEDTLS_SSL_IS_CLIENT,
                                     MBEDTLS_SSL_TRANSPORT_STREAM,
                                     MBEDTLS_SSL_PRESET_DEFAULT);
@@ -394,20 +394,20 @@ mbed_connect_step1(struct connectdata *conn,
   }
 
   /* new profile with RSA min key len = 1024 ... */
-  mbedtls_ssl_conf_cert_profile(&BACKEND->config,
+  mbedtls_ssl_conf_cert_profile(&backend->config,
                                 &mbedtls_x509_crt_profile_fr);
 
   switch(SSL_CONN_CONFIG(version)) {
   case CURL_SSLVERSION_DEFAULT:
   case CURL_SSLVERSION_TLSv1:
-    mbedtls_ssl_conf_min_version(&BACKEND->config, MBEDTLS_SSL_MAJOR_VERSION_3,
+    mbedtls_ssl_conf_min_version(&backend->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                  MBEDTLS_SSL_MINOR_VERSION_1);
     infof(data, "mbedTLS: Set min SSL version to TLS 1.0\n");
     break;
   case CURL_SSLVERSION_SSLv3:
-    mbedtls_ssl_conf_min_version(&BACKEND->config, MBEDTLS_SSL_MAJOR_VERSION_3,
+    mbedtls_ssl_conf_min_version(&backend->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                  MBEDTLS_SSL_MINOR_VERSION_0);
-    mbedtls_ssl_conf_max_version(&BACKEND->config, MBEDTLS_SSL_MAJOR_VERSION_3,
+    mbedtls_ssl_conf_max_version(&backend->config, MBEDTLS_SSL_MAJOR_VERSION_3,
                                  MBEDTLS_SSL_MINOR_VERSION_0);
     infof(data, "mbedTLS: Set SSL version to SSLv3\n");
     break;
@@ -426,25 +426,25 @@ mbed_connect_step1(struct connectdata *conn,
     return CURLE_SSL_CONNECT_ERROR;
   }
 
-  mbedtls_ssl_conf_authmode(&BACKEND->config, MBEDTLS_SSL_VERIFY_OPTIONAL);
+  mbedtls_ssl_conf_authmode(&backend->config, MBEDTLS_SSL_VERIFY_OPTIONAL);
 
-  mbedtls_ssl_conf_rng(&BACKEND->config, mbedtls_ctr_drbg_random,
-                       &BACKEND->ctr_drbg);
-  mbedtls_ssl_set_bio(&BACKEND->ssl, &conn->sock[sockindex],
+  mbedtls_ssl_conf_rng(&backend->config, mbedtls_ctr_drbg_random,
+                       &backend->ctr_drbg);
+  mbedtls_ssl_set_bio(&backend->ssl, &conn->sock[sockindex],
                       mbedtls_net_send,
                       mbedtls_net_recv,
                       NULL /*  rev_timeout() */);
 
-  mbedtls_ssl_conf_ciphersuites(&BACKEND->config,
+  mbedtls_ssl_conf_ciphersuites(&backend->config,
                                 mbedtls_ssl_list_ciphersuites());
 
 #if defined(MBEDTLS_SSL_RENEGOTIATION)
-  mbedtls_ssl_conf_renegotiation(&BACKEND->config,
+  mbedtls_ssl_conf_renegotiation(&backend->config,
                                  MBEDTLS_SSL_RENEGOTIATION_ENABLED);
 #endif
 
 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
-  mbedtls_ssl_conf_session_tickets(&BACKEND->config,
+  mbedtls_ssl_conf_session_tickets(&backend->config,
                                    MBEDTLS_SSL_SESSION_TICKETS_DISABLED);
 #endif
 
@@ -454,7 +454,7 @@ mbed_connect_step1(struct connectdata *conn,
 
     Curl_ssl_sessionid_lock(conn);
     if(!Curl_ssl_getsessionid(conn, &old_session, NULL, sockindex)) {
-      ret = mbedtls_ssl_set_session(&BACKEND->ssl, old_session);
+      ret = mbedtls_ssl_set_session(&backend->ssl, old_session);
       if(ret) {
         Curl_ssl_sessionid_unlock(conn);
         failf(data, "mbedtls_ssl_set_session returned -0x%x", -ret);
@@ -465,15 +465,15 @@ mbed_connect_step1(struct connectdata *conn,
     Curl_ssl_sessionid_unlock(conn);
   }
 
-  mbedtls_ssl_conf_ca_chain(&BACKEND->config,
-                            &BACKEND->cacert,
-                            &BACKEND->crl);
+  mbedtls_ssl_conf_ca_chain(&backend->config,
+                            &backend->cacert,
+                            &backend->crl);
 
   if(SSL_SET_OPTION(key)) {
-    mbedtls_ssl_conf_own_cert(&BACKEND->config,
-                              &BACKEND->clicert, &BACKEND->pk);
+    mbedtls_ssl_conf_own_cert(&backend->config,
+                              &backend->clicert, &backend->pk);
   }
-  if(mbedtls_ssl_set_hostname(&BACKEND->ssl, hostname)) {
+  if(mbedtls_ssl_set_hostname(&backend->ssl, hostname)) {
     /* mbedtls_ssl_set_hostname() sets the name to use in CN/SAN checks *and*
        the name to set in the SNI extension. So even if curl connects to a
        host specified as an IP address, this function must be used. */
@@ -483,7 +483,7 @@ mbed_connect_step1(struct connectdata *conn,
 
 #ifdef HAS_ALPN
   if(conn->bits.tls_enable_alpn) {
-    const char **p = &BACKEND->protocols[0];
+    const char **p = &backend->protocols[0];
 #ifdef USE_NGHTTP2
     if(data->set.httpversion >= CURL_HTTP_VERSION_2)
       *p++ = NGHTTP2_PROTO_VERSION_ID;
@@ -492,19 +492,19 @@ mbed_connect_step1(struct connectdata *conn,
     *p = NULL;
     /* this function doesn't clone the protocols array, which is why we need
        to keep it around */
-    if(mbedtls_ssl_conf_alpn_protocols(&BACKEND->config,
-                                       &BACKEND->protocols[0])) {
+    if(mbedtls_ssl_conf_alpn_protocols(&backend->config,
+                                       &backend->protocols[0])) {
       failf(data, "Failed setting ALPN protocols");
       return CURLE_SSL_CONNECT_ERROR;
     }
-    for(p = &BACKEND->protocols[0]; *p; ++p)
+    for(p = &backend->protocols[0]; *p; ++p)
       infof(data, "ALPN, offering %s\n", *p);
   }
 #endif
 
 #ifdef MBEDTLS_DEBUG
   /* In order to make that work in mbedtls MBEDTLS_DEBUG_C must be defined. */
-  mbedtls_ssl_conf_dbg(&BACKEND->config, mbed_debug, data);
+  mbedtls_ssl_conf_dbg(&backend->config, mbed_debug, data);
   /* - 0 No debug
    * - 1 Error
    * - 2 State change
@@ -516,7 +516,7 @@ mbed_connect_step1(struct connectdata *conn,
 
   /* give application a chance to interfere with mbedTLS set up. */
   if(data->set.ssl.fsslctx) {
-    ret = (*data->set.ssl.fsslctx)(data, &BACKEND->config,
+    ret = (*data->set.ssl.fsslctx)(data, &backend->config,
                                    data->set.ssl.fsslctxp);
     if(ret) {
       failf(data, "error signaled by ssl ctx callback");
@@ -536,15 +536,16 @@ mbed_connect_step2(struct connectdata *conn,
   int ret;
   struct Curl_easy *data = conn->data;
   struct ssl_connect_data* connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   const mbedtls_x509_crt *peercert;
   const char * const pinnedpubkey = SSL_IS_PROXY() ?
-        data->set.str[STRING_SSL_PINNEDPUBLICKEY_PROXY] :
-        data->set.str[STRING_SSL_PINNEDPUBLICKEY_ORIG];
+    data->set.str[STRING_SSL_PINNEDPUBLICKEY_PROXY] :
+    data->set.str[STRING_SSL_PINNEDPUBLICKEY_ORIG];
 
   conn->recv[sockindex] = mbed_recv;
   conn->send[sockindex] = mbed_send;
 
-  ret = mbedtls_ssl_handshake(&BACKEND->ssl);
+  ret = mbedtls_ssl_handshake(&backend->ssl);
 
   if(ret == MBEDTLS_ERR_SSL_WANT_READ) {
     connssl->connecting_state = ssl_connect_2_reading;
@@ -566,10 +567,10 @@ mbed_connect_step2(struct connectdata *conn,
   }
 
   infof(data, "mbedTLS: Handshake complete, cipher is %s\n",
-        mbedtls_ssl_get_ciphersuite(&BACKEND->ssl)
+        mbedtls_ssl_get_ciphersuite(&backend->ssl)
     );
 
-  ret = mbedtls_ssl_get_verify_result(&BACKEND->ssl);
+  ret = mbedtls_ssl_get_verify_result(&backend->ssl);
 
   if(!SSL_CONN_CONFIG(verifyhost))
     /* Ignore hostname errors if verifyhost is disabled */
@@ -594,7 +595,7 @@ mbed_connect_step2(struct connectdata *conn,
     return CURLE_PEER_FAILED_VERIFICATION;
   }
 
-  peercert = mbedtls_ssl_get_peer_cert(&BACKEND->ssl);
+  peercert = mbedtls_ssl_get_peer_cert(&backend->ssl);
 
   if(peercert && data->set.verbose) {
     const size_t bufsize = 16384;
@@ -664,7 +665,7 @@ mbed_connect_step2(struct connectdata *conn,
 
 #ifdef HAS_ALPN
   if(conn->bits.tls_enable_alpn) {
-    const char *next_protocol = mbedtls_ssl_get_alpn_protocol(&BACKEND->ssl);
+    const char *next_protocol = mbedtls_ssl_get_alpn_protocol(&backend->ssl);
 
     if(next_protocol) {
       infof(data, "ALPN, server accepted to use %s\n", next_protocol);
@@ -701,6 +702,7 @@ mbed_connect_step3(struct connectdata *conn,
 {
   CURLcode retcode = CURLE_OK;
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   struct Curl_easy *data = conn->data;
 
   DEBUGASSERT(ssl_connect_3 == connssl->connecting_state);
@@ -716,7 +718,7 @@ mbed_connect_step3(struct connectdata *conn,
 
     mbedtls_ssl_session_init(our_ssl_sessionid);
 
-    ret = mbedtls_ssl_get_session(&BACKEND->ssl, our_ssl_sessionid);
+    ret = mbedtls_ssl_get_session(&backend->ssl, our_ssl_sessionid);
     if(ret) {
       if(ret != MBEDTLS_ERR_SSL_ALLOC_FAILED)
         mbedtls_ssl_session_free(our_ssl_sessionid);
@@ -750,9 +752,10 @@ static ssize_t mbed_send(struct connectdata *conn, int sockindex,
                          CURLcode *curlcode)
 {
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   int ret = -1;
 
-  ret = mbedtls_ssl_write(&BACKEND->ssl,
+  ret = mbedtls_ssl_write(&backend->ssl,
                           (unsigned char *)mem, len);
 
   if(ret < 0) {
@@ -772,15 +775,16 @@ static void Curl_mbedtls_close_all(struct Curl_easy *data)
 static void Curl_mbedtls_close(struct connectdata *conn, int sockindex)
 {
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
-  mbedtls_pk_free(&BACKEND->pk);
-  mbedtls_x509_crt_free(&BACKEND->clicert);
-  mbedtls_x509_crt_free(&BACKEND->cacert);
-  mbedtls_x509_crl_free(&BACKEND->crl);
-  mbedtls_ssl_config_free(&BACKEND->config);
-  mbedtls_ssl_free(&BACKEND->ssl);
-  mbedtls_ctr_drbg_free(&BACKEND->ctr_drbg);
+  struct ssl_backend_data *backend = connssl->backend;
+  mbedtls_pk_free(&backend->pk);
+  mbedtls_x509_crt_free(&backend->clicert);
+  mbedtls_x509_crt_free(&backend->cacert);
+  mbedtls_x509_crl_free(&backend->crl);
+  mbedtls_ssl_config_free(&backend->config);
+  mbedtls_ssl_free(&backend->ssl);
+  mbedtls_ctr_drbg_free(&backend->ctr_drbg);
 #ifndef THREADING_SUPPORT
-  mbedtls_entropy_free(&BACKEND->entropy);
+  mbedtls_entropy_free(&backend->entropy);
 #endif /* THREADING_SUPPORT */
 }
 
@@ -789,11 +793,12 @@ static ssize_t mbed_recv(struct connectdata *conn, int num,
                          CURLcode *curlcode)
 {
   struct ssl_connect_data *connssl = &conn->ssl[num];
+  struct ssl_backend_data *backend = connssl->backend;
   int ret = -1;
   ssize_t len = -1;
 
   memset(buf, 0, buffersize);
-  ret = mbedtls_ssl_read(&BACKEND->ssl, (unsigned char *)buf,
+  ret = mbedtls_ssl_read(&backend->ssl, (unsigned char *)buf,
                          buffersize);
 
   if(ret <= 0) {
@@ -1029,7 +1034,8 @@ static bool Curl_mbedtls_data_pending(const struct connectdata *conn,
                                       int sockindex)
 {
   const struct ssl_connect_data *connssl = &conn->ssl[sockindex];
-  return mbedtls_ssl_get_bytes_avail(&BACKEND->ssl) != 0;
+  struct ssl_backend_data *backend = connssl->backend;
+  return mbedtls_ssl_get_bytes_avail(&backend->ssl) != 0;
 }
 
 static CURLcode Curl_mbedtls_sha256sum(const unsigned char *input,
@@ -1051,8 +1057,9 @@ static CURLcode Curl_mbedtls_sha256sum(const unsigned char *input,
 static void *Curl_mbedtls_get_internals(struct ssl_connect_data *connssl,
                                         CURLINFO info UNUSED_PARAM)
 {
+  struct ssl_backend_data *backend = connssl->backend;
   (void)info;
-  return &BACKEND->ssl;
+  return &backend->ssl;
 }
 
 const struct Curl_ssl Curl_ssl_mbedtls = {
diff --git a/lib/vtls/nss.c b/lib/vtls/nss.c
index ef51b0d9..16ec409e 100644
--- a/lib/vtls/nss.c
+++ b/lib/vtls/nss.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -87,8 +87,6 @@ struct ssl_backend_data {
   PK11GenericObject *obj_clicert;
 };
 
-#define BACKEND connssl->backend
-
 static PRLock *nss_initlock = NULL;
 static PRLock *nss_crllock = NULL;
 static PRLock *nss_findslot_lock = NULL;
@@ -462,6 +460,7 @@ static CURLcode nss_create_object(struct ssl_connect_data *connssl,
 
   const int slot_id = (cacert) ? 0 : 1;
   char *slot_name = aprintf("PEM Token #%d", slot_id);
+  struct ssl_backend_data *backend = connssl->backend;
   if(!slot_name)
     return CURLE_OUT_OF_MEMORY;
 
@@ -495,14 +494,14 @@ static CURLcode nss_create_object(struct ssl_connect_data *connssl,
   if(!obj)
     return result;
 
-  if(insert_wrapped_ptr(&BACKEND->obj_list, obj) != CURLE_OK) {
+  if(insert_wrapped_ptr(&backend->obj_list, obj) != CURLE_OK) {
     PK11_DestroyGenericObject(obj);
     return CURLE_OUT_OF_MEMORY;
   }
 
   if(!cacert && CKO_CERTIFICATE == obj_class)
     /* store reference to a client certificate */
-    BACKEND->obj_clicert = obj;
+    backend->obj_clicert = obj;
 
   return CURLE_OK;
 }
@@ -1084,7 +1083,8 @@ static CURLcode cmp_peer_pubkey(struct ssl_connect_data *connssl,
                                 const char *pinnedpubkey)
 {
   CURLcode result = CURLE_SSL_PINNEDPUBKEYNOTMATCH;
-  struct Curl_easy *data = BACKEND->data;
+  struct ssl_backend_data *backend = connssl->backend;
+  struct Curl_easy *data = backend->data;
   CERTCertificate *cert;
 
   if(!pinnedpubkey)
@@ -1092,7 +1092,7 @@ static CURLcode cmp_peer_pubkey(struct ssl_connect_data *connssl,
     return CURLE_OK;
 
   /* get peer certificate */
-  cert = SSL_PeerCertificate(BACKEND->handle);
+  cert = SSL_PeerCertificate(backend->handle);
   if(cert) {
     /* extract public key from peer certificate */
     SECKEYPublicKey *pubkey = CERT_ExtractPublicKey(cert);
@@ -1136,11 +1136,12 @@ static SECStatus SelectClientCert(void *arg, PRFileDesc *sock,
                                   struct SECKEYPrivateKeyStr **pRetKey)
 {
   struct ssl_connect_data *connssl = (struct ssl_connect_data *)arg;
-  struct Curl_easy *data = BACKEND->data;
-  const char *nickname = BACKEND->client_nickname;
+  struct ssl_backend_data *backend = connssl->backend;
+  struct Curl_easy *data = backend->data;
+  const char *nickname = backend->client_nickname;
   static const char pem_slotname[] = "PEM Token #1";
 
-  if(BACKEND->obj_clicert) {
+  if(backend->obj_clicert) {
     /* use the cert/key provided by PEM reader */
     SECItem cert_der = { 0, NULL, 0 };
     void *proto_win = SSL_RevealPinArg(sock);
@@ -1153,7 +1154,7 @@ static SECStatus SelectClientCert(void *arg, PRFileDesc *sock,
       return SECFailure;
     }
 
-    if(PK11_ReadRawAttribute(PK11_TypeGeneric, BACKEND->obj_clicert, CKA_VALUE,
+    if(PK11_ReadRawAttribute(PK11_TypeGeneric, backend->obj_clicert, CKA_VALUE,
                              &cert_der) != SECSuccess) {
       failf(data, "NSS: CKA_VALUE not found in PK11 generic object");
       PK11_FreeSlot(slot);
@@ -1503,11 +1504,12 @@ static void Curl_nss_cleanup(void)
 static int Curl_nss_check_cxn(struct connectdata *conn)
 {
   struct ssl_connect_data *connssl = &conn->ssl[FIRSTSOCKET];
+  struct ssl_backend_data *backend = connssl->backend;
   int rc;
   char buf;
 
   rc =
-    PR_Recv(BACKEND->handle, (void *)&buf, 1, PR_MSG_PEEK,
+    PR_Recv(backend->handle, (void *)&buf, 1, PR_MSG_PEEK,
             PR_SecondsToInterval(1));
   if(rc > 0)
     return 1; /* connection still in place */
@@ -1521,26 +1523,27 @@ static int Curl_nss_check_cxn(struct connectdata *conn)
 static void nss_close(struct ssl_connect_data *connssl)
 {
   /* before the cleanup, check whether we are using a client certificate */
-  const bool client_cert = (BACKEND->client_nickname != NULL)
-    || (BACKEND->obj_clicert != NULL);
+  struct ssl_backend_data *backend = connssl->backend;
+  const bool client_cert = (backend->client_nickname != NULL)
+    || (backend->obj_clicert != NULL);
 
-  free(BACKEND->client_nickname);
-  BACKEND->client_nickname = NULL;
+  free(backend->client_nickname);
+  backend->client_nickname = NULL;
 
   /* destroy all NSS objects in order to avoid failure of NSS shutdown */
-  Curl_llist_destroy(&BACKEND->obj_list, NULL);
-  BACKEND->obj_clicert = NULL;
+  Curl_llist_destroy(&backend->obj_list, NULL);
+  backend->obj_clicert = NULL;
 
-  if(BACKEND->handle) {
+  if(backend->handle) {
     if(client_cert)
       /* A server might require different authentication based on the
        * particular path being requested by the client.  To support this
        * scenario, we must ensure that a connection will never reuse the
        * authentication data from a previous connection. */
-      SSL_InvalidateSession(BACKEND->handle);
+      SSL_InvalidateSession(backend->handle);
 
-    PR_Close(BACKEND->handle);
-    BACKEND->handle = NULL;
+    PR_Close(backend->handle);
+    backend->handle = NULL;
   }
 }
 
@@ -1551,15 +1554,16 @@ static void Curl_nss_close(struct connectdata *conn, int sockindex)
 {
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
   struct ssl_connect_data *connssl_proxy = &conn->proxy_ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
 
-  if(BACKEND->handle || connssl_proxy->backend->handle) {
+  if(backend->handle || connssl_proxy->backend->handle) {
     /* NSS closes the socket we previously handed to it, so we must mark it
        as closed to avoid double close */
     fake_sclose(conn->sock[sockindex]);
     conn->sock[sockindex] = CURL_SOCKET_BAD;
   }
 
-  if(BACKEND->handle)
+  if(backend->handle)
     /* nss_close(connssl) will transitively close also
        connssl_proxy->backend->handle if both are used. Clear it to avoid
        a double close leading to crash. */
@@ -1773,6 +1777,7 @@ static CURLcode nss_fail_connect(struct ssl_connect_data *connssl,
                                  CURLcode curlerr)
 {
   PRErrorCode err = 0;
+  struct ssl_backend_data *backend = connssl->backend;
 
   if(is_nss_error(curlerr)) {
     /* read NSPR error code */
@@ -1788,7 +1793,7 @@ static CURLcode nss_fail_connect(struct ssl_connect_data *connssl,
   }
 
   /* cleanup on connection failure */
-  Curl_llist_destroy(&BACKEND->obj_list, NULL);
+  Curl_llist_destroy(&backend->obj_list, NULL);
 
   return curlerr;
 }
@@ -1799,10 +1804,11 @@ static CURLcode nss_set_blocking(struct ssl_connect_data *connssl,
                                  bool blocking)
 {
   static PRSocketOptionData sock_opt;
+  struct ssl_backend_data *backend = connssl->backend;
   sock_opt.option = PR_SockOpt_Nonblocking;
   sock_opt.value.non_blocking = !blocking;
 
-  if(PR_SetSocketOption(BACKEND->handle, &sock_opt) != PR_SUCCESS)
+  if(PR_SetSocketOption(backend->handle, &sock_opt) != PR_SUCCESS)
     return nss_fail_connect(connssl, data, CURLE_SSL_CONNECT_ERROR);
 
   return CURLE_OK;
@@ -1818,6 +1824,7 @@ static CURLcode nss_setup_connect(struct connectdata *conn, int sockindex)
   struct Curl_easy *data = conn->data;
   curl_socket_t sockfd = conn->sock[sockindex];
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   CURLcode result;
   bool second_layer = FALSE;
   SSLVersionRange sslver_supported;
@@ -1835,10 +1842,10 @@ static CURLcode nss_setup_connect(struct connectdata *conn, int sockindex)
 #endif
   };
 
-  BACKEND->data = data;
+  backend->data = data;
 
   /* list of all NSS objects we need to destroy in Curl_nss_close() */
-  Curl_llist_init(&BACKEND->obj_list, nss_destroy_object);
+  Curl_llist_init(&backend->obj_list, nss_destroy_object);
 
   PR_Lock(nss_initlock);
   result = nss_init(conn->data);
@@ -1960,7 +1967,7 @@ static CURLcode nss_setup_connect(struct connectdata *conn, int sockindex)
     char *nickname = dup_nickname(data, SSL_SET_OPTION(cert));
     if(nickname) {
       /* we are not going to use libnsspem.so to read the client cert */
-      BACKEND->obj_clicert = NULL;
+      backend->obj_clicert = NULL;
     }
     else {
       CURLcode rv = cert_stuff(conn, sockindex, SSL_SET_OPTION(cert),
@@ -1973,10 +1980,10 @@ static CURLcode nss_setup_connect(struct connectdata *conn, int sockindex)
     }
 
     /* store the nickname for SelectClientCert() called during handshake */
-    BACKEND->client_nickname = nickname;
+    backend->client_nickname = nickname;
   }
   else
-    BACKEND->client_nickname = NULL;
+    backend->client_nickname = NULL;
 
   if(SSL_GetClientAuthDataHook(model, SelectClientCert,
                                (void *)connssl) != SECSuccess) {
@@ -2017,8 +2024,8 @@ static CURLcode nss_setup_connect(struct connectdata *conn, int sockindex)
   }
 
   /* import our model socket onto the current I/O stack */
-  BACKEND->handle = SSL_ImportFD(model, nspr_io);
-  if(!BACKEND->handle) {
+  backend->handle = SSL_ImportFD(model, nspr_io);
+  if(!backend->handle) {
     if(!second_layer)
       PR_Close(nspr_io);
     goto error;
@@ -2029,36 +2036,36 @@ static CURLcode nss_setup_connect(struct connectdata *conn, int sockindex)
 
   /* This is the password associated with the cert that we're using */
   if(SSL_SET_OPTION(key_passwd)) {
-    SSL_SetPKCS11PinArg(BACKEND->handle, SSL_SET_OPTION(key_passwd));
+    SSL_SetPKCS11PinArg(backend->handle, SSL_SET_OPTION(key_passwd));
   }
 
 #ifdef SSL_ENABLE_OCSP_STAPLING
   if(SSL_CONN_CONFIG(verifystatus)) {
-    if(SSL_OptionSet(BACKEND->handle, SSL_ENABLE_OCSP_STAPLING, PR_TRUE)
+    if(SSL_OptionSet(backend->handle, SSL_ENABLE_OCSP_STAPLING, PR_TRUE)
         != SECSuccess)
       goto error;
   }
 #endif
 
 #ifdef SSL_ENABLE_NPN
-  if(SSL_OptionSet(BACKEND->handle, SSL_ENABLE_NPN, conn->bits.tls_enable_npn
+  if(SSL_OptionSet(backend->handle, SSL_ENABLE_NPN, conn->bits.tls_enable_npn
                    ? PR_TRUE : PR_FALSE) != SECSuccess)
     goto error;
 #endif
 
 #ifdef SSL_ENABLE_ALPN
-  if(SSL_OptionSet(BACKEND->handle, SSL_ENABLE_ALPN, conn->bits.tls_enable_alpn
+  if(SSL_OptionSet(backend->handle, SSL_ENABLE_ALPN, conn->bits.tls_enable_alpn
                    ? PR_TRUE : PR_FALSE) != SECSuccess)
     goto error;
 #endif
 
 #if NSSVERNUM >= 0x030f04 /* 3.15.4 */
   if(data->set.ssl.falsestart) {
-    if(SSL_OptionSet(BACKEND->handle, SSL_ENABLE_FALSE_START, PR_TRUE)
+    if(SSL_OptionSet(backend->handle, SSL_ENABLE_FALSE_START, PR_TRUE)
         != SECSuccess)
       goto error;
 
-    if(SSL_SetCanFalseStartCallback(BACKEND->handle, CanFalseStartCallback,
+    if(SSL_SetCanFalseStartCallback(backend->handle, CanFalseStartCallback,
         conn) != SECSuccess)
       goto error;
   }
@@ -2082,24 +2089,24 @@ static CURLcode nss_setup_connect(struct connectdata *conn, int sockindex)
     memcpy(&protocols[cur], ALPN_HTTP_1_1, ALPN_HTTP_1_1_LENGTH);
     cur += ALPN_HTTP_1_1_LENGTH;
 
-    if(SSL_SetNextProtoNego(BACKEND->handle, protocols, cur) != SECSuccess)
+    if(SSL_SetNextProtoNego(backend->handle, protocols, cur) != SECSuccess)
       goto error;
   }
 #endif
 
 
   /* Force handshake on next I/O */
-  if(SSL_ResetHandshake(BACKEND->handle, /* asServer */ PR_FALSE)
+  if(SSL_ResetHandshake(backend->handle, /* asServer */ PR_FALSE)
       != SECSuccess)
     goto error;
 
   /* propagate hostname to the TLS layer */
-  if(SSL_SetURL(BACKEND->handle, SSL_IS_PROXY() ? conn->http_proxy.host.name :
+  if(SSL_SetURL(backend->handle, SSL_IS_PROXY() ? conn->http_proxy.host.name :
                 conn->host.name) != SECSuccess)
     goto error;
 
   /* prevent NSS from re-using the session for a different hostname */
-  if(SSL_SetSockPeerID(BACKEND->handle, SSL_IS_PROXY() ?
+  if(SSL_SetSockPeerID(backend->handle, SSL_IS_PROXY() ?
                        conn->http_proxy.host.name : conn->host.name)
      != SECSuccess)
     goto error;
@@ -2116,6 +2123,7 @@ error:
 static CURLcode nss_do_connect(struct connectdata *conn, int sockindex)
 {
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   struct Curl_easy *data = conn->data;
   CURLcode result = CURLE_SSL_CONNECT_ERROR;
   PRUint32 timeout;
@@ -2136,7 +2144,7 @@ static CURLcode nss_do_connect(struct connectdata *conn, int sockindex)
 
   /* Force the handshake now */
   timeout = PR_MillisecondsToInterval((PRUint32) time_left);
-  if(SSL_ForceHandshakeWithTimeout(BACKEND->handle, timeout) != SECSuccess) {
+  if(SSL_ForceHandshakeWithTimeout(backend->handle, timeout) != SECSuccess) {
     if(PR_GetError() == PR_WOULD_BLOCK_ERROR)
       /* blocking direction is updated by nss_update_connecting_state() */
       return CURLE_AGAIN;
@@ -2147,7 +2155,7 @@ static CURLcode nss_do_connect(struct connectdata *conn, int sockindex)
     goto error;
   }
 
-  result = display_conn_info(conn, BACKEND->handle);
+  result = display_conn_info(conn, backend->handle);
   if(result)
     goto error;
 
@@ -2156,7 +2164,7 @@ static CURLcode nss_do_connect(struct connectdata *conn, int sockindex)
     char *nickname = dup_nickname(data, SSL_SET_OPTION(issuercert));
     if(nickname) {
       /* we support only nicknames in case of issuercert for now */
-      ret = check_issuer_cert(BACKEND->handle, nickname);
+      ret = check_issuer_cert(backend->handle, nickname);
       free(nickname);
     }
 
@@ -2260,13 +2268,14 @@ static ssize_t nss_send(struct connectdata *conn,  /* connection data */
                         CURLcode *curlcode)
 {
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   ssize_t rc;
 
   /* The SelectClientCert() hook uses this for infof() and failf() but the
      handle stored in nss_setup_connect() could have already been freed. */
-  BACKEND->data = conn->data;
+  backend->data = conn->data;
 
-  rc = PR_Send(BACKEND->handle, mem, (int)len, 0, PR_INTERVAL_NO_WAIT);
+  rc = PR_Send(backend->handle, mem, (int)len, 0, PR_INTERVAL_NO_WAIT);
   if(rc < 0) {
     PRInt32 err = PR_GetError();
     if(err == PR_WOULD_BLOCK_ERROR)
@@ -2297,13 +2306,14 @@ static ssize_t nss_recv(struct connectdata *conn,  /* connection data */
                         CURLcode *curlcode)
 {
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   ssize_t nread;
 
   /* The SelectClientCert() hook uses this for infof() and failf() but the
      handle stored in nss_setup_connect() could have already been freed. */
-  BACKEND->data = conn->data;
+  backend->data = conn->data;
 
-  nread = PR_Recv(BACKEND->handle, buf, (int)buffersize, 0,
+  nread = PR_Recv(backend->handle, buf, (int)buffersize, 0,
                   PR_INTERVAL_NO_WAIT);
   if(nread < 0) {
     /* failed SSL read */
@@ -2364,6 +2374,9 @@ static CURLcode Curl_nss_md5sum(unsigned char *tmp, /* input */
   PK11Context *MD5pw = PK11_CreateDigestContext(SEC_OID_MD5);
   unsigned int MD5out;
 
+  if(!MD5pw)
+    return CURLE_NOT_BUILT_IN;
+
   PK11_DigestOp(MD5pw, tmp, curlx_uztoui(tmplen));
   PK11_DigestFinal(MD5pw, md5sum, &MD5out, curlx_uztoui(md5len));
   PK11_DestroyContext(MD5pw, PR_TRUE);
@@ -2379,6 +2392,9 @@ static CURLcode Curl_nss_sha256sum(const unsigned char *tmp, /* input */
   PK11Context *SHA256pw = PK11_CreateDigestContext(SEC_OID_SHA256);
   unsigned int SHA256out;
 
+  if(!SHA256pw)
+    return CURLE_NOT_BUILT_IN;
+
   PK11_DigestOp(SHA256pw, tmp, curlx_uztoui(tmplen));
   PK11_DigestFinal(SHA256pw, sha256sum, &SHA256out, curlx_uztoui(sha256len));
   PK11_DestroyContext(SHA256pw, PR_TRUE);
@@ -2407,8 +2423,9 @@ static bool Curl_nss_false_start(void)
 static void *Curl_nss_get_internals(struct ssl_connect_data *connssl,
                                     CURLINFO info UNUSED_PARAM)
 {
+  struct ssl_backend_data *backend = connssl->backend;
   (void)info;
-  return BACKEND->handle;
+  return backend->handle;
 }
 
 const struct Curl_ssl Curl_ssl_nss = {
diff --git a/lib/vtls/openssl.c b/lib/vtls/openssl.c
index 1d09cadc..176fa522 100644
--- a/lib/vtls/openssl.c
+++ b/lib/vtls/openssl.c
@@ -228,8 +228,6 @@ struct ssl_backend_data {
 #endif
 };
 
-#define BACKEND connssl->backend
-
 /*
  * Number of bytes to read from the random number seed file. This must be
  * a finite value (because some entropy "files" like /dev/urandom have
@@ -1269,19 +1267,19 @@ static struct curl_slist *Curl_ossl_engines_list(struct Curl_easy *data)
   return list;
 }
 
-
 static void ossl_close(struct ssl_connect_data *connssl)
 {
-  if(BACKEND->handle) {
-    (void)SSL_shutdown(BACKEND->handle);
-    SSL_set_connect_state(BACKEND->handle);
+  struct ssl_backend_data *backend = connssl->backend;
+  if(backend->handle) {
+    (void)SSL_shutdown(backend->handle);
+    SSL_set_connect_state(backend->handle);
 
-    SSL_free(BACKEND->handle);
-    BACKEND->handle = NULL;
+    SSL_free(backend->handle);
+    backend->handle = NULL;
   }
-  if(BACKEND->ctx) {
-    SSL_CTX_free(BACKEND->ctx);
-    BACKEND->ctx = NULL;
+  if(backend->ctx) {
+    SSL_CTX_free(backend->ctx);
+    backend->ctx = NULL;
   }
 }
 
@@ -1310,6 +1308,7 @@ static int Curl_ossl_shutdown(struct connectdata *conn, int sockindex)
   int buffsize;
   int err;
   bool done = FALSE;
+  struct ssl_backend_data *backend = connssl->backend;
 
 #ifndef CURL_DISABLE_FTP
   /* This has only been tested on the proftpd server, and the mod_tls code
@@ -1318,10 +1317,10 @@ static int Curl_ossl_shutdown(struct connectdata *conn, int sockindex)
      we do not send one. Let's hope other servers do the same... */
 
   if(data->set.ftp_ccc == CURLFTPSSL_CCC_ACTIVE)
-      (void)SSL_shutdown(BACKEND->handle);
+      (void)SSL_shutdown(backend->handle);
 #endif
 
-  if(BACKEND->handle) {
+  if(backend->handle) {
     buffsize = (int)sizeof(buf);
     while(!done) {
       int what = SOCKET_READABLE(conn->sock[sockindex],
@@ -1331,8 +1330,8 @@ static int Curl_ossl_shutdown(struct connectdata *conn, int sockindex)
 
         /* Something to read, let's do it and hope that it is the close
            notify alert from the server */
-        nread = (ssize_t)SSL_read(BACKEND->handle, buf, buffsize);
-        err = SSL_get_error(BACKEND->handle, (int)nread);
+        nread = (ssize_t)SSL_read(backend->handle, buf, buffsize);
+        err = SSL_get_error(backend->handle, (int)nread);
 
         switch(err) {
         case SSL_ERROR_NONE: /* this is not an error */
@@ -1377,7 +1376,7 @@ static int Curl_ossl_shutdown(struct connectdata *conn, int sockindex)
 
     if(data->set.verbose) {
 #ifdef HAVE_SSL_GET_SHUTDOWN
-      switch(SSL_get_shutdown(BACKEND->handle)) {
+      switch(SSL_get_shutdown(backend->handle)) {
       case SSL_SENT_SHUTDOWN:
         infof(data, "SSL_get_shutdown() returned SSL_SENT_SHUTDOWN\n");
         break;
@@ -1392,8 +1391,8 @@ static int Curl_ossl_shutdown(struct connectdata *conn, int sockindex)
 #endif
     }
 
-    SSL_free(BACKEND->handle);
-    BACKEND->handle = NULL;
+    SSL_free(backend->handle);
+    backend->handle = NULL;
   }
   return retval;
 }
@@ -1712,13 +1711,13 @@ static CURLcode verifystatus(struct connectdata *conn,
   const unsigned char *p;
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-
   OCSP_RESPONSE *rsp = NULL;
   OCSP_BASICRESP *br = NULL;
   X509_STORE     *st = NULL;
   STACK_OF(X509) *ch = NULL;
+  struct ssl_backend_data *backend = connssl->backend;
 
-  long len = SSL_get_tlsext_status_ocsp_resp(BACKEND->handle, &status);
+  long len = SSL_get_tlsext_status_ocsp_resp(backend->handle, &status);
 
   if(!status) {
     failf(data, "No OCSP response received");
@@ -1748,8 +1747,8 @@ static CURLcode verifystatus(struct connectdata *conn,
     goto end;
   }
 
-  ch = SSL_get_peer_cert_chain(BACKEND->handle);
-  st = SSL_CTX_get_cert_store(BACKEND->ctx);
+  ch = SSL_get_peer_cert_chain(backend->handle);
+  st = SSL_CTX_get_cert_store(backend->ctx);
 
 #if ((OPENSSL_VERSION_NUMBER <= 0x1000201fL) /* Fixed after 1.0.2a */ || \
      (defined(LIBRESSL_VERSION_NUMBER) &&                               \
@@ -1825,7 +1824,8 @@ static CURLcode verifystatus(struct connectdata *conn,
   }
 
 end:
-  if(br) OCSP_BASICRESP_free(br);
+  if(br)
+    OCSP_BASICRESP_free(br);
   OCSP_RESPONSE_free(rsp);
 
   return result;
@@ -2270,7 +2270,7 @@ set_ssl_version_min_max_legacy(ctx_option_t *ctx_options,
 #ifdef TLS1_3_VERSION
     {
       struct ssl_connect_data *connssl = &conn->ssl[sockindex];
-      SSL_CTX_set_max_proto_version(BACKEND->ctx, TLS1_3_VERSION);
+      SSL_CTX_set_max_proto_version(backend->ctx, TLS1_3_VERSION);
       *ctx_options |= SSL_OP_NO_TLSv1_2;
     }
 #else
@@ -2419,6 +2419,7 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
   const bool verifypeer = SSL_CONN_CONFIG(verifypeer);
   const char * const ssl_crlfile = SSL_SET_OPTION(CRLfile);
   char error_buffer[256];
+  struct ssl_backend_data *backend = connssl->backend;
 
   DEBUGASSERT(ssl_connect_1 == connssl->connecting_state);
 
@@ -2477,25 +2478,25 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
     return CURLE_SSL_CONNECT_ERROR;
   }
 
-  if(BACKEND->ctx)
-    SSL_CTX_free(BACKEND->ctx);
-  BACKEND->ctx = SSL_CTX_new(req_method);
+  if(backend->ctx)
+    SSL_CTX_free(backend->ctx);
+  backend->ctx = SSL_CTX_new(req_method);
 
-  if(!BACKEND->ctx) {
+  if(!backend->ctx) {
     failf(data, "SSL: couldn't create a context: %s",
           ossl_strerror(ERR_peek_error(), error_buffer, sizeof(error_buffer)));
     return CURLE_OUT_OF_MEMORY;
   }
 
 #ifdef SSL_MODE_RELEASE_BUFFERS
-  SSL_CTX_set_mode(BACKEND->ctx, SSL_MODE_RELEASE_BUFFERS);
+  SSL_CTX_set_mode(backend->ctx, SSL_MODE_RELEASE_BUFFERS);
 #endif
 
 #ifdef SSL_CTRL_SET_MSG_CALLBACK
   if(data->set.fdebug && data->set.verbose) {
     /* the SSL trace callback is only used for verbose logging */
-    SSL_CTX_set_msg_callback(BACKEND->ctx, ssl_tls_trace);
-    SSL_CTX_set_msg_callback_arg(BACKEND->ctx, conn);
+    SSL_CTX_set_msg_callback(backend->ctx, ssl_tls_trace);
+    SSL_CTX_set_msg_callback_arg(backend->ctx, conn);
   }
 #endif
 
@@ -2561,8 +2562,8 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
     /* "--sslv2" option means SSLv2 only, disable all others */
     case CURL_SSLVERSION_SSLv2:
 #if OPENSSL_VERSION_NUMBER >= 0x10100000L /* 1.1.0 */
-      SSL_CTX_set_min_proto_version(BACKEND->ctx, SSL2_VERSION);
-      SSL_CTX_set_max_proto_version(BACKEND->ctx, SSL2_VERSION);
+      SSL_CTX_set_min_proto_version(backend->ctx, SSL2_VERSION);
+      SSL_CTX_set_max_proto_version(backend->ctx, SSL2_VERSION);
 #else
       ctx_options |= SSL_OP_NO_SSLv3;
       ctx_options |= SSL_OP_NO_TLSv1;
@@ -2579,8 +2580,8 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
     /* "--sslv3" option means SSLv3 only, disable all others */
     case CURL_SSLVERSION_SSLv3:
 #if OPENSSL_VERSION_NUMBER >= 0x10100000L /* 1.1.0 */
-      SSL_CTX_set_min_proto_version(BACKEND->ctx, SSL3_VERSION);
-      SSL_CTX_set_max_proto_version(BACKEND->ctx, SSL3_VERSION);
+      SSL_CTX_set_min_proto_version(backend->ctx, SSL3_VERSION);
+      SSL_CTX_set_max_proto_version(backend->ctx, SSL3_VERSION);
 #else
       ctx_options |= SSL_OP_NO_SSLv2;
       ctx_options |= SSL_OP_NO_TLSv1;
@@ -2607,7 +2608,7 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
       ctx_options |= SSL_OP_NO_SSLv3;
 
 #if (OPENSSL_VERSION_NUMBER >= 0x10100000L) /* 1.1.0 */
-      result = set_ssl_version_min_max(BACKEND->ctx, conn);
+      result = set_ssl_version_min_max(backend->ctx, conn);
 #else
       result = set_ssl_version_min_max_legacy(&ctx_options, conn, sockindex);
 #endif
@@ -2620,11 +2621,11 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
       return CURLE_SSL_CONNECT_ERROR;
   }
 
-  SSL_CTX_set_options(BACKEND->ctx, ctx_options);
+  SSL_CTX_set_options(backend->ctx, ctx_options);
 
 #ifdef HAS_NPN
   if(conn->bits.tls_enable_npn)
-    SSL_CTX_set_next_proto_select_cb(BACKEND->ctx, select_next_proto_cb, conn);
+    SSL_CTX_set_next_proto_select_cb(backend->ctx, select_next_proto_cb, conn);
 #endif
 
 #ifdef HAS_ALPN
@@ -2652,12 +2653,12 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
     /* expects length prefixed preference ordered list of protocols in wire
      * format
      */
-    SSL_CTX_set_alpn_protos(BACKEND->ctx, protocols, cur);
+    SSL_CTX_set_alpn_protos(backend->ctx, protocols, cur);
   }
 #endif
 
   if(ssl_cert || ssl_cert_type) {
-    if(!cert_stuff(conn, BACKEND->ctx, ssl_cert, ssl_cert_type,
+    if(!cert_stuff(conn, backend->ctx, ssl_cert, ssl_cert_type,
                    SSL_SET_OPTION(key), SSL_SET_OPTION(key_type),
                    SSL_SET_OPTION(key_passwd))) {
       /* failf() is already done in cert_stuff() */
@@ -2669,7 +2670,7 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
   if(!ciphers)
     ciphers = (char *)DEFAULT_CIPHER_SELECTION;
   if(ciphers) {
-    if(!SSL_CTX_set_cipher_list(BACKEND->ctx, ciphers)) {
+    if(!SSL_CTX_set_cipher_list(backend->ctx, ciphers)) {
       failf(data, "failed setting cipher list: %s", ciphers);
       return CURLE_SSL_CIPHER;
     }
@@ -2680,7 +2681,7 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
   {
     char *ciphers13 = SSL_CONN_CONFIG(cipher_list13);
     if(ciphers13) {
-      if(!SSL_CTX_set_ciphersuites(BACKEND->ctx, ciphers13)) {
+      if(!SSL_CTX_set_ciphersuites(backend->ctx, ciphers13)) {
         failf(data, "failed setting TLS 1.3 cipher suite: %s", ciphers13);
         return CURLE_SSL_CIPHER;
       }
@@ -2691,7 +2692,7 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
 
 #ifdef HAVE_SSL_CTX_SET_POST_HANDSHAKE_AUTH
   /* OpenSSL 1.1.1 requires clients to opt-in for PHA */
-  SSL_CTX_set_post_handshake_auth(BACKEND->ctx, 1);
+  SSL_CTX_set_post_handshake_auth(backend->ctx, 1);
 #endif
 
 #ifdef USE_TLS_SRP
@@ -2700,18 +2701,18 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
 
     infof(data, "Using TLS-SRP username: %s\n", ssl_username);
 
-    if(!SSL_CTX_set_srp_username(BACKEND->ctx, ssl_username)) {
+    if(!SSL_CTX_set_srp_username(backend->ctx, ssl_username)) {
       failf(data, "Unable to set SRP user name");
       return CURLE_BAD_FUNCTION_ARGUMENT;
     }
-    if(!SSL_CTX_set_srp_password(BACKEND->ctx, SSL_SET_OPTION(password))) {
+    if(!SSL_CTX_set_srp_password(backend->ctx, SSL_SET_OPTION(password))) {
       failf(data, "failed setting SRP password");
       return CURLE_BAD_FUNCTION_ARGUMENT;
     }
     if(!SSL_CONN_CONFIG(cipher_list)) {
       infof(data, "Setting cipher list SRP\n");
 
-      if(!SSL_CTX_set_cipher_list(BACKEND->ctx, "SRP")) {
+      if(!SSL_CTX_set_cipher_list(backend->ctx, "SRP")) {
         failf(data, "failed setting SRP cipher list");
         return CURLE_SSL_CIPHER;
       }
@@ -2719,10 +2720,37 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
   }
 #endif
 
+#if defined(OPENSSL_VERSION_MAJOR) && (OPENSSL_VERSION_MAJOR >= 3)
+  /* OpenSSL 3.0.0 has deprecated SSL_CTX_load_verify_locations */
+  if(ssl_cafile) {
+    if(!SSL_CTX_load_verify_file(backend->ctx, ssl_cafile)) {
+      if(verifypeer) {
+        /* Fail if we insist on successfully verifying the server. */
+        failf(data, "error setting certificate file: %s", ssl_cafile);
+        return CURLE_SSL_CACERT_BADFILE;
+      }
+      /* Continue with a warning if no certificate verification is required. */
+      infof(data, "error setting certificate file, continuing anyway\n");
+    }
+    infof(data, "  CAfile: %s\n", ssl_cafile);
+  }
+  if(ssl_capath) {
+    if(!SSL_CTX_load_verify_dir(backend->ctx, ssl_capath)) {
+      if(verifypeer) {
+        /* Fail if we insist on successfully verifying the server. */
+        failf(data, "error setting certificate path: %s", ssl_capath);
+        return CURLE_SSL_CACERT_BADFILE;
+      }
+      /* Continue with a warning if no certificate verification is required. */
+      infof(data, "error setting certificate path, continuing anyway\n");
+    }
+    infof(data, "  CApath: %s\n", ssl_capath);
+  }
+#else
   if(ssl_cafile || ssl_capath) {
     /* tell SSL where to find CA certificates that are used to verify
        the servers certificate. */
-    if(!SSL_CTX_load_verify_locations(BACKEND->ctx, ssl_cafile, ssl_capath)) {
+    if(!SSL_CTX_load_verify_locations(backend->ctx, ssl_cafile, ssl_capath)) {
       if(verifypeer) {
         /* Fail if we insist on successfully verifying the server. */
         failf(data, "error setting certificate verify locations:\n"
@@ -2746,18 +2774,20 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
           ssl_cafile ? ssl_cafile : "none",
           ssl_capath ? ssl_capath : "none");
   }
+#endif
+
 #ifdef CURL_CA_FALLBACK
   else if(verifypeer) {
     /* verifying the peer without any CA certificates won't
        work so use openssl's built in default as fallback */
-    SSL_CTX_set_default_verify_paths(BACKEND->ctx);
+    SSL_CTX_set_default_verify_paths(backend->ctx);
   }
 #endif
 
   if(ssl_crlfile) {
     /* tell SSL where to find CRL file that is used to check certificate
      * revocation */
-    lookup = X509_STORE_add_lookup(SSL_CTX_get_cert_store(BACKEND->ctx),
+    lookup = X509_STORE_add_lookup(SSL_CTX_get_cert_store(backend->ctx),
                                  X509_LOOKUP_file());
     if(!lookup ||
        (!X509_load_crl_file(lookup, ssl_crlfile, X509_FILETYPE_PEM)) ) {
@@ -2766,7 +2796,7 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
     }
     /* Everything is fine. */
     infof(data, "successfully load CRL file:\n");
-    X509_STORE_set_flags(SSL_CTX_get_cert_store(BACKEND->ctx),
+    X509_STORE_set_flags(SSL_CTX_get_cert_store(backend->ctx),
                          X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL);
 
     infof(data, "  CRLfile: %s\n", ssl_crlfile);
@@ -2781,7 +2811,7 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
        https://rt.openssl.org/Ticket/Display.html?id=3621&user=guest&pass=guest
     */
 #if defined(X509_V_FLAG_TRUSTED_FIRST) && !defined(X509_V_FLAG_NO_ALT_CHAINS)
-    X509_STORE_set_flags(SSL_CTX_get_cert_store(BACKEND->ctx),
+    X509_STORE_set_flags(SSL_CTX_get_cert_store(backend->ctx),
                          X509_V_FLAG_TRUSTED_FIRST);
 #endif
 #ifdef X509_V_FLAG_PARTIAL_CHAIN
@@ -2790,7 +2820,7 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
          trust-anchors, in the same way as self-signed root CA certificates
          are. This allows users to verify servers using the intermediate cert
          only, instead of needing the whole chain. */
-      X509_STORE_set_flags(SSL_CTX_get_cert_store(BACKEND->ctx),
+      X509_STORE_set_flags(SSL_CTX_get_cert_store(backend->ctx),
                            X509_V_FLAG_PARTIAL_CHAIN);
     }
 #endif
@@ -2800,13 +2830,13 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
    * fail to connect if the verification fails, or if it should continue
    * anyway. In the latter case the result of the verification is checked with
    * SSL_get_verify_result() below. */
-  SSL_CTX_set_verify(BACKEND->ctx,
+  SSL_CTX_set_verify(backend->ctx,
                      verifypeer ? SSL_VERIFY_PEER : SSL_VERIFY_NONE, NULL);
 
   /* Enable logging of secrets to the file specified in env SSLKEYLOGFILE. */
 #if defined(ENABLE_SSLKEYLOGFILE) && defined(HAVE_KEYLOG_CALLBACK)
   if(keylog_file_fp) {
-    SSL_CTX_set_keylog_callback(BACKEND->ctx, ossl_keylog_callback);
+    SSL_CTX_set_keylog_callback(backend->ctx, ossl_keylog_callback);
   }
 #endif
 
@@ -2814,14 +2844,14 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
    * callback. Use the "external storage" mode to avoid that OpenSSL creates
    * an internal session cache.
    */
-  SSL_CTX_set_session_cache_mode(BACKEND->ctx,
+  SSL_CTX_set_session_cache_mode(backend->ctx,
       SSL_SESS_CACHE_CLIENT | SSL_SESS_CACHE_NO_INTERNAL);
-  SSL_CTX_sess_set_new_cb(BACKEND->ctx, ossl_new_session_cb);
+  SSL_CTX_sess_set_new_cb(backend->ctx, ossl_new_session_cb);
 
   /* give application a chance to interfere with SSL set up. */
   if(data->set.ssl.fsslctx) {
     Curl_set_in_callback(data, true);
-    result = (*data->set.ssl.fsslctx)(data, BACKEND->ctx,
+    result = (*data->set.ssl.fsslctx)(data, backend->ctx,
                                       data->set.ssl.fsslctxp);
     Curl_set_in_callback(data, false);
     if(result) {
@@ -2831,10 +2861,10 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
   }
 
   /* Lets make an SSL structure */
-  if(BACKEND->handle)
-    SSL_free(BACKEND->handle);
-  BACKEND->handle = SSL_new(BACKEND->ctx);
-  if(!BACKEND->handle) {
+  if(backend->handle)
+    SSL_free(backend->handle);
+  backend->handle = SSL_new(backend->ctx);
+  if(!backend->handle) {
     failf(data, "SSL: couldn't create a context (handle)!");
     return CURLE_OUT_OF_MEMORY;
   }
@@ -2842,23 +2872,23 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
 #if (OPENSSL_VERSION_NUMBER >= 0x0090808fL) && !defined(OPENSSL_NO_TLSEXT) && \
     !defined(OPENSSL_NO_OCSP)
   if(SSL_CONN_CONFIG(verifystatus))
-    SSL_set_tlsext_status_type(BACKEND->handle, TLSEXT_STATUSTYPE_ocsp);
+    SSL_set_tlsext_status_type(backend->handle, TLSEXT_STATUSTYPE_ocsp);
 #endif
 
 #if defined(OPENSSL_IS_BORINGSSL) && defined(ALLOW_RENEG)
-  SSL_set_renegotiate_mode(BACKEND->handle, ssl_renegotiate_freely);
+  SSL_set_renegotiate_mode(backend->handle, ssl_renegotiate_freely);
 #endif
 
-  SSL_set_connect_state(BACKEND->handle);
+  SSL_set_connect_state(backend->handle);
 
-  BACKEND->server_cert = 0x0;
+  backend->server_cert = 0x0;
 #ifdef SSL_CTRL_SET_TLSEXT_HOSTNAME
   if((0 == Curl_inet_pton(AF_INET, hostname, &addr)) &&
 #ifdef ENABLE_IPV6
      (0 == Curl_inet_pton(AF_INET6, hostname, &addr)) &&
 #endif
      sni &&
-     !SSL_set_tlsext_host_name(BACKEND->handle, hostname))
+     !SSL_set_tlsext_host_name(backend->handle, hostname))
     infof(data, "WARNING: failed to configure server name indication (SNI) "
           "TLS extension\n");
 #endif
@@ -2872,14 +2902,14 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
     if(connectdata_idx >= 0 && sockindex_idx >= 0) {
       /* Store the data needed for the "new session" callback.
        * The sockindex is stored as a pointer to an array element. */
-      SSL_set_ex_data(BACKEND->handle, connectdata_idx, conn);
-      SSL_set_ex_data(BACKEND->handle, sockindex_idx, conn->sock + sockindex);
+      SSL_set_ex_data(backend->handle, connectdata_idx, conn);
+      SSL_set_ex_data(backend->handle, sockindex_idx, conn->sock + sockindex);
     }
 
     Curl_ssl_sessionid_lock(conn);
     if(!Curl_ssl_getsessionid(conn, &ssl_sessionid, NULL, sockindex)) {
       /* we got a session id, use it! */
-      if(!SSL_set_session(BACKEND->handle, ssl_sessionid)) {
+      if(!SSL_set_session(backend->handle, ssl_sessionid)) {
         Curl_ssl_sessionid_unlock(conn);
         failf(data, "SSL: SSL_set_session failed: %s",
               ossl_strerror(ERR_get_error(), error_buffer,
@@ -2899,9 +2929,9 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
     DEBUGASSERT(handle != NULL);
     DEBUGASSERT(bio != NULL);
     BIO_set_ssl(bio, handle, FALSE);
-    SSL_set_bio(BACKEND->handle, bio, bio);
+    SSL_set_bio(backend->handle, bio, bio);
   }
-  else if(!SSL_set_fd(BACKEND->handle, (int)sockfd)) {
+  else if(!SSL_set_fd(backend->handle, (int)sockfd)) {
     /* pass the raw socket into the SSL layers */
     failf(data, "SSL: SSL_set_fd failed: %s",
           ossl_strerror(ERR_get_error(), error_buffer, sizeof(error_buffer)));
@@ -2920,24 +2950,25 @@ static CURLcode ossl_connect_step2(struct connectdata *conn, int sockindex)
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
   long * const certverifyresult = SSL_IS_PROXY() ?
     &data->set.proxy_ssl.certverifyresult : &data->set.ssl.certverifyresult;
+  struct ssl_backend_data *backend = connssl->backend;
   DEBUGASSERT(ssl_connect_2 == connssl->connecting_state
               || ssl_connect_2_reading == connssl->connecting_state
               || ssl_connect_2_writing == connssl->connecting_state);
 
   ERR_clear_error();
 
-  err = SSL_connect(BACKEND->handle);
+  err = SSL_connect(backend->handle);
   /* If keylogging is enabled but the keylog callback is not supported then log
      secrets here, immediately after SSL_connect by using tap_ssl_key. */
 #if defined(ENABLE_SSLKEYLOGFILE) && !defined(HAVE_KEYLOG_CALLBACK)
-  tap_ssl_key(BACKEND->handle, &BACKEND->tap_state);
+  tap_ssl_key(backend->handle, &backend->tap_state);
 #endif
 
   /* 1  is fine
      0  is "not successful but was shut down controlled"
      <0 is "handshake was not successful, because a fatal error occurred" */
   if(1 != err) {
-    int detail = SSL_get_error(BACKEND->handle, err);
+    int detail = SSL_get_error(backend->handle, err);
 
     if(SSL_ERROR_WANT_READ == detail) {
       connssl->connecting_state = ssl_connect_2_reading;
@@ -2977,7 +3008,7 @@ static CURLcode ossl_connect_step2(struct connectdata *conn, int sockindex)
          (reason == SSL_R_CERTIFICATE_VERIFY_FAILED)) {
         result = CURLE_PEER_FAILED_VERIFICATION;
 
-        lerr = SSL_get_verify_result(BACKEND->handle);
+        lerr = SSL_get_verify_result(backend->handle);
         if(lerr != X509_V_OK) {
           *certverifyresult = lerr;
           msnprintf(error_buffer, sizeof(error_buffer),
@@ -3026,8 +3057,8 @@ static CURLcode ossl_connect_step2(struct connectdata *conn, int sockindex)
 
     /* Informational message */
     infof(data, "SSL connection using %s / %s\n",
-          get_ssl_version_txt(BACKEND->handle),
-          SSL_get_cipher(BACKEND->handle));
+          get_ssl_version_txt(backend->handle),
+          SSL_get_cipher(backend->handle));
 
 #ifdef HAS_ALPN
     /* Sets data and len to negotiated protocol, len is 0 if no protocol was
@@ -3036,7 +3067,7 @@ static CURLcode ossl_connect_step2(struct connectdata *conn, int sockindex)
     if(conn->bits.tls_enable_alpn) {
       const unsigned char *neg_protocol;
       unsigned int len;
-      SSL_get0_alpn_selected(BACKEND->handle, &neg_protocol, &len);
+      SSL_get0_alpn_selected(backend->handle, &neg_protocol, &len);
       if(len != 0) {
         infof(data, "ALPN, server accepted to use %.*s\n", len, neg_protocol);
 
@@ -3171,8 +3202,9 @@ static CURLcode get_cert_chain(struct connectdata *conn,
   struct Curl_easy *data = conn->data;
   numcert_t numcerts;
   BIO *mem;
+  struct ssl_backend_data *backend = connssl->backend;
 
-  sk = SSL_get_peer_cert_chain(BACKEND->handle);
+  sk = SSL_get_peer_cert_chain(backend->handle);
   if(!sk) {
     return CURLE_OUT_OF_MEMORY;
   }
@@ -3458,13 +3490,14 @@ static CURLcode servercert(struct connectdata *conn,
   long * const certverifyresult = SSL_IS_PROXY() ?
     &data->set.proxy_ssl.certverifyresult : &data->set.ssl.certverifyresult;
   BIO *mem = BIO_new(BIO_s_mem());
+  struct ssl_backend_data *backend = connssl->backend;
 
   if(data->set.ssl.certinfo)
     /* we've been asked to gather certificate info! */
     (void)get_cert_chain(conn, connssl);
 
-  BACKEND->server_cert = SSL_get_peer_certificate(BACKEND->handle);
-  if(!BACKEND->server_cert) {
+  backend->server_cert = SSL_get_peer_certificate(backend->handle);
+  if(!backend->server_cert) {
     BIO_free(mem);
     if(!strict)
       return CURLE_OK;
@@ -3475,19 +3508,19 @@ static CURLcode servercert(struct connectdata *conn,
 
   infof(data, "%s certificate:\n", SSL_IS_PROXY() ? "Proxy" : "Server");
 
-  rc = x509_name_oneline(X509_get_subject_name(BACKEND->server_cert),
+  rc = x509_name_oneline(X509_get_subject_name(backend->server_cert),
                          buffer, sizeof(buffer));
   infof(data, " subject: %s\n", rc?"[NONE]":buffer);
 
 #ifndef CURL_DISABLE_VERBOSE_STRINGS
   {
     long len;
-    ASN1_TIME_print(mem, X509_get0_notBefore(BACKEND->server_cert));
+    ASN1_TIME_print(mem, X509_get0_notBefore(backend->server_cert));
     len = BIO_get_mem_data(mem, (char **) &ptr);
     infof(data, " start date: %.*s\n", len, ptr);
     (void)BIO_reset(mem);
 
-    ASN1_TIME_print(mem, X509_get0_notAfter(BACKEND->server_cert));
+    ASN1_TIME_print(mem, X509_get0_notAfter(backend->server_cert));
     len = BIO_get_mem_data(mem, (char **) &ptr);
     infof(data, " expire date: %.*s\n", len, ptr);
     (void)BIO_reset(mem);
@@ -3497,15 +3530,15 @@ static CURLcode servercert(struct connectdata *conn,
   BIO_free(mem);
 
   if(SSL_CONN_CONFIG(verifyhost)) {
-    result = verifyhost(conn, BACKEND->server_cert);
+    result = verifyhost(conn, backend->server_cert);
     if(result) {
-      X509_free(BACKEND->server_cert);
-      BACKEND->server_cert = NULL;
+      X509_free(backend->server_cert);
+      backend->server_cert = NULL;
       return result;
     }
   }
 
-  rc = x509_name_oneline(X509_get_issuer_name(BACKEND->server_cert),
+  rc = x509_name_oneline(X509_get_issuer_name(backend->server_cert),
                          buffer, sizeof(buffer));
   if(rc) {
     if(strict)
@@ -3527,8 +3560,8 @@ static CURLcode servercert(struct connectdata *conn,
               " error %s",
               ossl_strerror(ERR_get_error(), error_buffer,
                             sizeof(error_buffer)) );
-        X509_free(BACKEND->server_cert);
-        BACKEND->server_cert = NULL;
+        X509_free(backend->server_cert);
+        backend->server_cert = NULL;
         return CURLE_OUT_OF_MEMORY;
       }
 
@@ -3537,8 +3570,8 @@ static CURLcode servercert(struct connectdata *conn,
           failf(data, "SSL: Unable to open issuer cert (%s)",
                 SSL_SET_OPTION(issuercert));
         BIO_free(fp);
-        X509_free(BACKEND->server_cert);
-        BACKEND->server_cert = NULL;
+        X509_free(backend->server_cert);
+        backend->server_cert = NULL;
         return CURLE_SSL_ISSUER_ERROR;
       }
 
@@ -3549,19 +3582,19 @@ static CURLcode servercert(struct connectdata *conn,
                 SSL_SET_OPTION(issuercert));
         BIO_free(fp);
         X509_free(issuer);
-        X509_free(BACKEND->server_cert);
-        BACKEND->server_cert = NULL;
+        X509_free(backend->server_cert);
+        backend->server_cert = NULL;
         return CURLE_SSL_ISSUER_ERROR;
       }
 
-      if(X509_check_issued(issuer, BACKEND->server_cert) != X509_V_OK) {
+      if(X509_check_issued(issuer, backend->server_cert) != X509_V_OK) {
         if(strict)
           failf(data, "SSL: Certificate issuer check failed (%s)",
                 SSL_SET_OPTION(issuercert));
         BIO_free(fp);
         X509_free(issuer);
-        X509_free(BACKEND->server_cert);
-        BACKEND->server_cert = NULL;
+        X509_free(backend->server_cert);
+        backend->server_cert = NULL;
         return CURLE_SSL_ISSUER_ERROR;
       }
 
@@ -3571,7 +3604,7 @@ static CURLcode servercert(struct connectdata *conn,
       X509_free(issuer);
     }
 
-    lerr = *certverifyresult = SSL_get_verify_result(BACKEND->handle);
+    lerr = *certverifyresult = SSL_get_verify_result(backend->handle);
 
     if(*certverifyresult != X509_V_OK) {
       if(SSL_CONN_CONFIG(verifypeer)) {
@@ -3596,8 +3629,8 @@ static CURLcode servercert(struct connectdata *conn,
   if(SSL_CONN_CONFIG(verifystatus)) {
     result = verifystatus(conn, connssl);
     if(result) {
-      X509_free(BACKEND->server_cert);
-      BACKEND->server_cert = NULL;
+      X509_free(backend->server_cert);
+      backend->server_cert = NULL;
       return result;
     }
   }
@@ -3610,13 +3643,13 @@ static CURLcode servercert(struct connectdata *conn,
   ptr = SSL_IS_PROXY() ? data->set.str[STRING_SSL_PINNEDPUBLICKEY_PROXY] :
                          data->set.str[STRING_SSL_PINNEDPUBLICKEY_ORIG];
   if(!result && ptr) {
-    result = pkp_pin_peer_pubkey(data, BACKEND->server_cert, ptr);
+    result = pkp_pin_peer_pubkey(data, backend->server_cert, ptr);
     if(result)
       failf(data, "SSL: public key does not match pinned public key!");
   }
 
-  X509_free(BACKEND->server_cert);
-  BACKEND->server_cert = NULL;
+  X509_free(backend->server_cert);
+  backend->server_cert = NULL;
   connssl->connecting_state = ssl_connect_done;
 
   return result;
@@ -3810,14 +3843,15 @@ static ssize_t ossl_send(struct connectdata *conn,
   int memlen;
   int rc;
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
 
   ERR_clear_error();
 
   memlen = (len > (size_t)INT_MAX) ? INT_MAX : (int)len;
-  rc = SSL_write(BACKEND->handle, mem, memlen);
+  rc = SSL_write(backend->handle, mem, memlen);
 
   if(rc <= 0) {
-    err = SSL_get_error(BACKEND->handle, rc);
+    err = SSL_get_error(backend->handle, rc);
 
     switch(err) {
     case SSL_ERROR_WANT_READ:
@@ -3884,14 +3918,15 @@ static ssize_t ossl_recv(struct connectdata *conn, /* connection data */
   ssize_t nread;
   int buffsize;
   struct ssl_connect_data *connssl = &conn->ssl[num];
+  struct ssl_backend_data *backend = connssl->backend;
 
   ERR_clear_error();
 
   buffsize = (buffersize > (size_t)INT_MAX) ? INT_MAX : (int)buffersize;
-  nread = (ssize_t)SSL_read(BACKEND->handle, buf, buffsize);
+  nread = (ssize_t)SSL_read(backend->handle, buf, buffsize);
   if(nread <= 0) {
     /* failed SSL_read */
-    int err = SSL_get_error(BACKEND->handle, (int)nread);
+    int err = SSL_get_error(backend->handle, (int)nread);
 
     switch(err) {
     case SSL_ERROR_NONE: /* this is not an error */
@@ -4097,8 +4132,9 @@ static void *Curl_ossl_get_internals(struct ssl_connect_data *connssl,
                                      CURLINFO info)
 {
   /* Legacy: CURLINFO_TLS_SESSION must return an SSL_CTX pointer. */
+  struct ssl_backend_data *backend = connssl->backend;
   return info == CURLINFO_TLS_SESSION ?
-         (void *)BACKEND->ctx : (void *)BACKEND->handle;
+         (void *)backend->ctx : (void *)backend->handle;
 }
 
 const struct Curl_ssl Curl_ssl_openssl = {
diff --git a/lib/vtls/schannel.c b/lib/vtls/schannel.c
index f665ee34..49659bb7 100644
--- a/lib/vtls/schannel.c
+++ b/lib/vtls/schannel.c
@@ -520,8 +520,15 @@ schannel_connect_step1(struct connectdata *conn, int sockindex)
         DEBUGF(infof(data, "schannel: disabled server certificate revocation "
                      "checks\n"));
       }
+      else if(data->set.ssl.revoke_best_effort) {
+        schannel_cred.dwFlags |= SCH_CRED_IGNORE_NO_REVOCATION_CHECK |
+          SCH_CRED_IGNORE_REVOCATION_OFFLINE | SCH_CRED_REVOCATION_CHECK_CHAIN;
+
+        DEBUGF(infof(data, "schannel: ignore revocation offline errors"));
+      }
       else {
         schannel_cred.dwFlags |= SCH_CRED_REVOCATION_CHECK_CHAIN;
+
         DEBUGF(infof(data,
                      "schannel: checking server certificate revocation\n"));
       }
@@ -578,11 +585,12 @@ schannel_connect_step1(struct connectdata *conn, int sockindex)
     /* client certificate */
     if(data->set.ssl.cert) {
       DWORD cert_store_name;
-      TCHAR *cert_store_path;
+      TCHAR *cert_store_path = NULL;
       TCHAR *cert_thumbprint_str;
       CRYPT_HASH_BLOB cert_thumbprint;
       BYTE cert_thumbprint_data[CERT_THUMBPRINT_DATA_LEN];
       HCERTSTORE cert_store;
+      FILE *fInCert = NULL;
 
       TCHAR *cert_path = Curl_convert_UTF8_to_tchar(data->set.ssl.cert);
       if(!cert_path)
@@ -590,54 +598,143 @@ schannel_connect_step1(struct connectdata *conn, int sockindex)
 
       result = get_cert_location(cert_path, &cert_store_name,
                                  &cert_store_path, &cert_thumbprint_str);
-      if(result != CURLE_OK) {
-        failf(data, "schannel: Failed to get certificate location for %s",
-              cert_path);
+      if((result != CURLE_OK) && (data->set.ssl.cert[0]!='\0'))
+        fInCert = fopen(data->set.ssl.cert, "rb");
+
+      if((result != CURLE_OK) && (fInCert == NULL)) {
+        failf(data, "schannel: Failed to get certificate location"
+              " or file for %s",
+              data->set.ssl.cert);
         Curl_unicodefree(cert_path);
         return result;
       }
 
-      cert_store =
-        CertOpenStore(CURL_CERT_STORE_PROV_SYSTEM, 0,
-                      (HCRYPTPROV)NULL,
-                      CERT_STORE_OPEN_EXISTING_FLAG | cert_store_name,
-                      cert_store_path);
-      if(!cert_store) {
-        failf(data, "schannel: Failed to open cert store %x %s, "
-              "last error is %x",
-              cert_store_name, cert_store_path, GetLastError());
-        free(cert_store_path);
+      if(fInCert) {
+        /* Reading a .P12 or .pfx file, like the example at bottom of
+           https://social.msdn.microsoft.com/Forums/windowsdesktop/
+           en-US/3e7bc95f-b21a-4bcd-bd2c-7f996718cae5
+        */
+        void *certdata = NULL;
+        long filesize = 0;
+        CRYPT_DATA_BLOB datablob;
+        WCHAR* pszPassword;
+        size_t pwd_len = 0;
+        int str_w_len = 0;
+        int continue_reading = fseek(fInCert, 0, SEEK_END) == 0;
+        if(continue_reading)
+          filesize = ftell(fInCert);
+        if(filesize < 0)
+          continue_reading = 0;
+        if(continue_reading)
+          continue_reading = fseek(fInCert, 0, SEEK_SET) == 0;
+        if(continue_reading)
+          certdata = malloc(((size_t)filesize) + 1);
+        if((certdata == NULL) ||
+           ((int) fread(certdata, (size_t)filesize, 1, fInCert) != 1))
+          continue_reading = 0;
+        fclose(fInCert);
         Curl_unicodefree(cert_path);
-        return CURLE_SSL_CERTPROBLEM;
-      }
-      free(cert_store_path);
 
-      cert_thumbprint.pbData = cert_thumbprint_data;
-      cert_thumbprint.cbData = CERT_THUMBPRINT_DATA_LEN;
+        if(!continue_reading) {
+          failf(data, "schannel: Failed to read cert file %s",
+                data->set.ssl.cert);
+          free(certdata);
+          return CURLE_SSL_CERTPROBLEM;
+        }
 
-      if(!CryptStringToBinary(cert_thumbprint_str, CERT_THUMBPRINT_STR_LEN,
-                              CRYPT_STRING_HEX,
-                              cert_thumbprint_data, &cert_thumbprint.cbData,
-                              NULL, NULL)) {
-        Curl_unicodefree(cert_path);
-        return CURLE_SSL_CERTPROBLEM;
-      }
+        /* Convert key-pair data to the in-memory certificate store */
+        datablob.pbData = (BYTE*)certdata;
+        datablob.cbData = (DWORD)filesize;
+
+        if(data->set.ssl.key_passwd != NULL)
+          pwd_len = strlen(data->set.ssl.key_passwd);
+        pszPassword = (WCHAR*)malloc(sizeof(WCHAR)*(pwd_len + 1));
+        if(pwd_len > 0)
+          str_w_len =
+            MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS,
+                                data->set.ssl.key_passwd, (int)pwd_len,
+                                pszPassword, (int)(pwd_len + 1));
+
+        if((str_w_len >= 0) && (str_w_len <= (int)pwd_len))
+          pszPassword[str_w_len] = 0;
+        else
+          pszPassword[0] = 0;
+
+        cert_store = PFXImportCertStore(&datablob, pszPassword, 0);
+        free(pszPassword);
+        free(certdata);
+        if(cert_store == NULL) {
+          DWORD errorcode = GetLastError();
+          if(errorcode == ERROR_INVALID_PASSWORD)
+            failf(data, "schannel: Failed to import cert file %s, "
+                  "password is bad", data->set.ssl.cert);
+          else
+            failf(data, "schannel: Failed to import cert file %s, "
+                  "last error is 0x%x", data->set.ssl.cert, errorcode);
+          return CURLE_SSL_CERTPROBLEM;
+        }
 
-      client_certs[0] = CertFindCertificateInStore(
-        cert_store, X509_ASN_ENCODING | PKCS_7_ASN_ENCODING, 0,
-        CERT_FIND_HASH, &cert_thumbprint, NULL);
+        client_certs[0] = CertFindCertificateInStore(
+            cert_store, X509_ASN_ENCODING | PKCS_7_ASN_ENCODING, 0,
+            CERT_FIND_ANY, NULL, NULL);
 
-      Curl_unicodefree(cert_path);
+        if(client_certs[0] == NULL) {
+          failf(data, "schannel: Failed to get certificate from file %s"
+                ", last error is 0x%x",
+                data->set.ssl.cert, GetLastError());
+          CertCloseStore(cert_store, 0);
+          return CURLE_SSL_CERTPROBLEM;
+        }
 
-      if(client_certs[0]) {
         schannel_cred.cCreds = 1;
         schannel_cred.paCred = client_certs;
       }
       else {
-        /* CRYPT_E_NOT_FOUND / E_INVALIDARG */
-        return CURLE_SSL_CERTPROBLEM;
-      }
+        cert_store =
+          CertOpenStore(CURL_CERT_STORE_PROV_SYSTEM, 0,
+                        (HCRYPTPROV)NULL,
+                        CERT_STORE_OPEN_EXISTING_FLAG | cert_store_name,
+                        cert_store_path);
+        if(!cert_store) {
+          failf(data, "schannel: Failed to open cert store %x %s, "
+                "last error is 0x%x",
+                cert_store_name, cert_store_path, GetLastError());
+          free(cert_store_path);
+          Curl_unicodefree(cert_path);
+          return CURLE_SSL_CERTPROBLEM;
+        }
+        free(cert_store_path);
+
+        cert_thumbprint.pbData = cert_thumbprint_data;
+        cert_thumbprint.cbData = CERT_THUMBPRINT_DATA_LEN;
+
+        if(!CryptStringToBinary(cert_thumbprint_str,
+                                CERT_THUMBPRINT_STR_LEN,
+                                CRYPT_STRING_HEX,
+                                cert_thumbprint_data,
+                                &cert_thumbprint.cbData,
+                                NULL, NULL)) {
+          Curl_unicodefree(cert_path);
+          CertCloseStore(cert_store, 0);
+          return CURLE_SSL_CERTPROBLEM;
+        }
+
+        client_certs[0] = CertFindCertificateInStore(
+          cert_store, X509_ASN_ENCODING | PKCS_7_ASN_ENCODING, 0,
+          CERT_FIND_HASH, &cert_thumbprint, NULL);
+
+        Curl_unicodefree(cert_path);
 
+        if(client_certs[0]) {
+          schannel_cred.cCreds = 1;
+          schannel_cred.paCred = client_certs;
+        }
+        else {
+          /* CRYPT_E_NOT_FOUND / E_INVALIDARG */
+          CertCloseStore(cert_store, 0);
+          return CURLE_SSL_CERTPROBLEM;
+        }
+      }
       CertCloseStore(cert_store, 0);
     }
 #else
@@ -1534,13 +1631,13 @@ schannel_send(struct connectdata *conn, int sockindex,
     /* send entire message or fail */
     while(len > (size_t)written) {
       ssize_t this_write;
-      timediff_t timeleft;
+      timediff_t timeout_ms;
       int what;
 
       this_write = 0;
 
-      timeleft = Curl_timeleft(conn->data, NULL, FALSE);
-      if(timeleft < 0) {
+      timeout_ms = Curl_timeleft(conn->data, NULL, FALSE);
+      if(timeout_ms < 0) {
         /* we already got the timeout */
         failf(conn->data, "schannel: timed out sending data "
               "(bytes sent: %zd)", written);
@@ -1548,8 +1645,9 @@ schannel_send(struct connectdata *conn, int sockindex,
         written = -1;
         break;
       }
-
-      what = SOCKET_WRITABLE(conn->sock[sockindex], timeleft);
+      if(!timeout_ms)
+        timeout_ms = TIMEDIFF_T_MAX;
+      what = SOCKET_WRITABLE(conn->sock[sockindex], timeout_ms);
       if(what < 0) {
         /* fatal error */
         failf(conn->data, "select/poll on SSL socket, errno: %d", SOCKERRNO);
@@ -2203,7 +2301,7 @@ static void Curl_schannel_checksum(const unsigned char *input,
   memset(checksum, 0, checksumlen);
 
   if(!CryptAcquireContext(&hProv, NULL, NULL, provType,
-                          CRYPT_VERIFYCONTEXT))
+                          CRYPT_VERIFYCONTEXT | CRYPT_SILENT))
     return; /* failed */
 
   do {
diff --git a/lib/vtls/schannel_verify.c b/lib/vtls/schannel_verify.c
index e75132ca..3dbc11f0 100644
--- a/lib/vtls/schannel_verify.c
+++ b/lib/vtls/schannel_verify.c
@@ -636,6 +636,15 @@ CURLcode Curl_verify_certificate(struct connectdata *conn, int sockindex)
       CERT_SIMPLE_CHAIN *pSimpleChain = pChainContext->rgpChain[0];
       DWORD dwTrustErrorMask = ~(DWORD)(CERT_TRUST_IS_NOT_TIME_NESTED);
       dwTrustErrorMask &= pSimpleChain->TrustStatus.dwErrorStatus;
+
+      if(data->set.ssl.revoke_best_effort) {
+        /* Ignore errors when root certificates are missing the revocation
+         * list URL, or when the list could not be downloaded because the
+         * server is currently unreachable. */
+        dwTrustErrorMask &= ~(DWORD)(CERT_TRUST_REVOCATION_STATUS_UNKNOWN |
+          CERT_TRUST_IS_OFFLINE_REVOCATION);
+      }
+
       if(dwTrustErrorMask) {
         if(dwTrustErrorMask & CERT_TRUST_IS_REVOKED)
           failf(data, "schannel: CertGetCertificateChain trust error"
diff --git a/lib/vtls/sectransp.c b/lib/vtls/sectransp.c
index 7dd028fb..6b2d436f 100644
--- a/lib/vtls/sectransp.c
+++ b/lib/vtls/sectransp.c
@@ -138,8 +138,6 @@ struct ssl_backend_data {
   size_t ssl_write_buffered_length;
 };
 
-#define BACKEND connssl->backend
-
 /* pinned public key support tests */
 
 /* version 1 supports macOS 10.12+ and iOS 10+ */
@@ -201,7 +199,8 @@ static OSStatus SocketRead(SSLConnectionRef connection,
   UInt8 *currData = (UInt8 *)data;
   /*int sock = *(int *)connection;*/
   struct ssl_connect_data *connssl = (struct ssl_connect_data *)connection;
-  int sock = BACKEND->ssl_sockfd;
+  struct ssl_backend_data *backend = connssl->backend;
+  int sock = backend->ssl_sockfd;
   OSStatus rtn = noErr;
   size_t bytesRead;
   ssize_t rrtn;
@@ -230,7 +229,7 @@ static OSStatus SocketRead(SSLConnectionRef connection,
             break;
           case EAGAIN:
             rtn = errSSLWouldBlock;
-            BACKEND->ssl_direction = false;
+            backend->ssl_direction = false;
             break;
           default:
             rtn = ioErr;
@@ -261,7 +260,8 @@ static OSStatus SocketWrite(SSLConnectionRef connection,
   size_t bytesSent = 0;
   /*int sock = *(int *)connection;*/
   struct ssl_connect_data *connssl = (struct ssl_connect_data *)connection;
-  int sock = BACKEND->ssl_sockfd;
+  struct ssl_backend_data *backend = connssl->backend;
+  int sock = backend->ssl_sockfd;
   ssize_t length;
   size_t dataLen = *dataLength;
   const UInt8 *dataPtr = (UInt8 *)data;
@@ -281,7 +281,7 @@ static OSStatus SocketWrite(SSLConnectionRef connection,
     theErr = errno;
     if(theErr == EAGAIN) {
       ortn = errSSLWouldBlock;
-      BACKEND->ssl_direction = true;
+      backend->ssl_direction = true;
     }
     else {
       ortn = ioErr;
@@ -1276,6 +1276,7 @@ set_ssl_version_min_max(struct connectdata *conn, int sockindex)
 {
   struct Curl_easy *data = conn->data;
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   long ssl_version = SSL_CONN_CONFIG(version);
   long ssl_version_max = SSL_CONN_CONFIG(version_max);
   long max_supported_version_by_os;
@@ -1326,30 +1327,30 @@ set_ssl_version_min_max(struct connectdata *conn, int sockindex)
       return result;
     }
 
-    (void)SSLSetProtocolVersionMin(BACKEND->ssl_ctx, darwin_ver_min);
-    (void)SSLSetProtocolVersionMax(BACKEND->ssl_ctx, darwin_ver_max);
+    (void)SSLSetProtocolVersionMin(backend->ssl_ctx, darwin_ver_min);
+    (void)SSLSetProtocolVersionMax(backend->ssl_ctx, darwin_ver_max);
     return result;
   }
   else {
 #if CURL_SUPPORT_MAC_10_8
     long i = ssl_version;
-    (void)SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+    (void)SSLSetProtocolVersionEnabled(backend->ssl_ctx,
                                        kSSLProtocolAll,
                                        false);
     for(; i <= (ssl_version_max >> 16); i++) {
       switch(i) {
         case CURL_SSLVERSION_TLSv1_0:
-          (void)SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+          (void)SSLSetProtocolVersionEnabled(backend->ssl_ctx,
                                             kTLSProtocol1,
                                             true);
           break;
         case CURL_SSLVERSION_TLSv1_1:
-          (void)SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+          (void)SSLSetProtocolVersionEnabled(backend->ssl_ctx,
                                             kTLSProtocol11,
                                             true);
           break;
         case CURL_SSLVERSION_TLSv1_2:
-          (void)SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+          (void)SSLSetProtocolVersionEnabled(backend->ssl_ctx,
                                             kTLSProtocol12,
                                             true);
           break;
@@ -1373,6 +1374,7 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
   struct Curl_easy *data = conn->data;
   curl_socket_t sockfd = conn->sock[sockindex];
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   const char * const ssl_cafile = SSL_CONN_CONFIG(CAfile);
   const bool verifypeer = SSL_CONN_CONFIG(verifypeer);
   char * const ssl_cert = SSL_SET_OPTION(cert);
@@ -1395,10 +1397,10 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
 
 #if CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS
   if(SSLCreateContext != NULL) {  /* use the newer API if available */
-    if(BACKEND->ssl_ctx)
-      CFRelease(BACKEND->ssl_ctx);
-    BACKEND->ssl_ctx = SSLCreateContext(NULL, kSSLClientSide, kSSLStreamType);
-    if(!BACKEND->ssl_ctx) {
+    if(backend->ssl_ctx)
+      CFRelease(backend->ssl_ctx);
+    backend->ssl_ctx = SSLCreateContext(NULL, kSSLClientSide, kSSLStreamType);
+    if(!backend->ssl_ctx) {
       failf(data, "SSL: couldn't create a context!");
       return CURLE_OUT_OF_MEMORY;
     }
@@ -1406,9 +1408,9 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
   else {
   /* The old ST API does not exist under iOS, so don't compile it: */
 #if CURL_SUPPORT_MAC_10_8
-    if(BACKEND->ssl_ctx)
-      (void)SSLDisposeContext(BACKEND->ssl_ctx);
-    err = SSLNewContext(false, &(BACKEND->ssl_ctx));
+    if(backend->ssl_ctx)
+      (void)SSLDisposeContext(backend->ssl_ctx);
+    err = SSLNewContext(false, &(backend->ssl_ctx));
     if(err != noErr) {
       failf(data, "SSL: couldn't create a context: OSStatus %d", err);
       return CURLE_OUT_OF_MEMORY;
@@ -1416,31 +1418,31 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
 #endif /* CURL_SUPPORT_MAC_10_8 */
   }
 #else
-  if(BACKEND->ssl_ctx)
-    (void)SSLDisposeContext(BACKEND->ssl_ctx);
-  err = SSLNewContext(false, &(BACKEND->ssl_ctx));
+  if(backend->ssl_ctx)
+    (void)SSLDisposeContext(backend->ssl_ctx);
+  err = SSLNewContext(false, &(backend->ssl_ctx));
   if(err != noErr) {
     failf(data, "SSL: couldn't create a context: OSStatus %d", err);
     return CURLE_OUT_OF_MEMORY;
   }
 #endif /* CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS */
-  BACKEND->ssl_write_buffered_length = 0UL; /* reset buffered write length */
+  backend->ssl_write_buffered_length = 0UL; /* reset buffered write length */
 
   /* check to see if we've been told to use an explicit SSL/TLS version */
 #if CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS
   if(SSLSetProtocolVersionMax != NULL) {
     switch(conn->ssl_config.version) {
     case CURL_SSLVERSION_TLSv1:
-      (void)SSLSetProtocolVersionMin(BACKEND->ssl_ctx, kTLSProtocol1);
+      (void)SSLSetProtocolVersionMin(backend->ssl_ctx, kTLSProtocol1);
 #if (CURL_BUILD_MAC_10_13 || CURL_BUILD_IOS_11) && HAVE_BUILTIN_AVAILABLE == 1
       if(__builtin_available(macOS 10.13, iOS 11.0, *)) {
-        (void)SSLSetProtocolVersionMax(BACKEND->ssl_ctx, kTLSProtocol13);
+        (void)SSLSetProtocolVersionMax(backend->ssl_ctx, kTLSProtocol13);
       }
       else {
-        (void)SSLSetProtocolVersionMax(BACKEND->ssl_ctx, kTLSProtocol12);
+        (void)SSLSetProtocolVersionMax(backend->ssl_ctx, kTLSProtocol12);
       }
 #else
-      (void)SSLSetProtocolVersionMax(BACKEND->ssl_ctx, kTLSProtocol12);
+      (void)SSLSetProtocolVersionMax(backend->ssl_ctx, kTLSProtocol12);
 #endif /* (CURL_BUILD_MAC_10_13 || CURL_BUILD_IOS_11) &&
           HAVE_BUILTIN_AVAILABLE == 1 */
       break;
@@ -1456,20 +1458,20 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
         break;
       }
     case CURL_SSLVERSION_SSLv3:
-      err = SSLSetProtocolVersionMin(BACKEND->ssl_ctx, kSSLProtocol3);
+      err = SSLSetProtocolVersionMin(backend->ssl_ctx, kSSLProtocol3);
       if(err != noErr) {
         failf(data, "Your version of the OS does not support SSLv3");
         return CURLE_SSL_CONNECT_ERROR;
       }
-      (void)SSLSetProtocolVersionMax(BACKEND->ssl_ctx, kSSLProtocol3);
+      (void)SSLSetProtocolVersionMax(backend->ssl_ctx, kSSLProtocol3);
       break;
     case CURL_SSLVERSION_SSLv2:
-      err = SSLSetProtocolVersionMin(BACKEND->ssl_ctx, kSSLProtocol2);
+      err = SSLSetProtocolVersionMin(backend->ssl_ctx, kSSLProtocol2);
       if(err != noErr) {
         failf(data, "Your version of the OS does not support SSLv2");
         return CURLE_SSL_CONNECT_ERROR;
       }
-      (void)SSLSetProtocolVersionMax(BACKEND->ssl_ctx, kSSLProtocol2);
+      (void)SSLSetProtocolVersionMax(backend->ssl_ctx, kSSLProtocol2);
       break;
     default:
       failf(data, "Unrecognized parameter passed via CURLOPT_SSLVERSION");
@@ -1478,19 +1480,19 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
   }
   else {
 #if CURL_SUPPORT_MAC_10_8
-    (void)SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+    (void)SSLSetProtocolVersionEnabled(backend->ssl_ctx,
                                        kSSLProtocolAll,
                                        false);
     switch(conn->ssl_config.version) {
     case CURL_SSLVERSION_DEFAULT:
     case CURL_SSLVERSION_TLSv1:
-      (void)SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+      (void)SSLSetProtocolVersionEnabled(backend->ssl_ctx,
                                          kTLSProtocol1,
                                          true);
-      (void)SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+      (void)SSLSetProtocolVersionEnabled(backend->ssl_ctx,
                                          kTLSProtocol11,
                                          true);
-      (void)SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+      (void)SSLSetProtocolVersionEnabled(backend->ssl_ctx,
                                          kTLSProtocol12,
                                          true);
       break;
@@ -1505,7 +1507,7 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
         break;
       }
     case CURL_SSLVERSION_SSLv3:
-      err = SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+      err = SSLSetProtocolVersionEnabled(backend->ssl_ctx,
                                          kSSLProtocol3,
                                          true);
       if(err != noErr) {
@@ -1514,7 +1516,7 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
       }
       break;
     case CURL_SSLVERSION_SSLv2:
-      err = SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+      err = SSLSetProtocolVersionEnabled(backend->ssl_ctx,
                                          kSSLProtocol2,
                                          true);
       if(err != noErr) {
@@ -1534,12 +1536,12 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
                 " SSL/TLS version");
     return CURLE_SSL_CONNECT_ERROR;
   }
-  (void)SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx, kSSLProtocolAll, false);
+  (void)SSLSetProtocolVersionEnabled(backend->ssl_ctx, kSSLProtocolAll, false);
   switch(conn->ssl_config.version) {
   case CURL_SSLVERSION_DEFAULT:
   case CURL_SSLVERSION_TLSv1:
   case CURL_SSLVERSION_TLSv1_0:
-    (void)SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+    (void)SSLSetProtocolVersionEnabled(backend->ssl_ctx,
                                        kTLSProtocol1,
                                        true);
     break;
@@ -1553,7 +1555,7 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
     failf(data, "Your version of the OS does not support TLSv1.3");
     return CURLE_SSL_CONNECT_ERROR;
   case CURL_SSLVERSION_SSLv2:
-    err = SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+    err = SSLSetProtocolVersionEnabled(backend->ssl_ctx,
                                        kSSLProtocol2,
                                        true);
     if(err != noErr) {
@@ -1562,7 +1564,7 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
     }
     break;
   case CURL_SSLVERSION_SSLv3:
-    err = SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+    err = SSLSetProtocolVersionEnabled(backend->ssl_ctx,
                                        kSSLProtocol3,
                                        true);
     if(err != noErr) {
@@ -1596,7 +1598,7 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
       /* expects length prefixed preference ordered list of protocols in wire
        * format
        */
-      err = SSLSetALPNProtocols(BACKEND->ssl_ctx, alpnArr);
+      err = SSLSetALPNProtocols(backend->ssl_ctx, alpnArr);
       if(err != noErr)
         infof(data, "WARNING: failed to set ALPN protocols; OSStatus %d\n",
               err);
@@ -1657,7 +1659,7 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
       certs_c[0] = cert_and_key;
       certs = CFArrayCreate(NULL, (const void **)certs_c, 1L,
                             &kCFTypeArrayCallBacks);
-      err = SSLSetCertificate(BACKEND->ssl_ctx, certs);
+      err = SSLSetCertificate(backend->ssl_ctx, certs);
       if(certs)
         CFRelease(certs);
       if(err != noErr) {
@@ -1720,7 +1722,7 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
   if(SSLSetSessionOption != NULL) {
 #endif /* CURL_BUILD_MAC */
     bool break_on_auth = !conn->ssl_config.verifypeer || ssl_cafile;
-    err = SSLSetSessionOption(BACKEND->ssl_ctx,
+    err = SSLSetSessionOption(backend->ssl_ctx,
                               kSSLSessionOptionBreakOnServerAuth,
                               break_on_auth);
     if(err != noErr) {
@@ -1730,7 +1732,7 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
   }
   else {
 #if CURL_SUPPORT_MAC_10_8
-    err = SSLSetEnableCertVerify(BACKEND->ssl_ctx,
+    err = SSLSetEnableCertVerify(backend->ssl_ctx,
                                  conn->ssl_config.verifypeer?true:false);
     if(err != noErr) {
       failf(data, "SSL: SSLSetEnableCertVerify() failed: OSStatus %d", err);
@@ -1739,7 +1741,7 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
 #endif /* CURL_SUPPORT_MAC_10_8 */
   }
 #else
-  err = SSLSetEnableCertVerify(BACKEND->ssl_ctx,
+  err = SSLSetEnableCertVerify(backend->ssl_ctx,
                                conn->ssl_config.verifypeer?true:false);
   if(err != noErr) {
     failf(data, "SSL: SSLSetEnableCertVerify() failed: OSStatus %d", err);
@@ -1760,7 +1762,7 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
    * Both hostname check and SNI require SSLSetPeerDomainName().
    * Also: the verifyhost setting influences SNI usage */
   if(conn->ssl_config.verifyhost) {
-    err = SSLSetPeerDomainName(BACKEND->ssl_ctx, hostname,
+    err = SSLSetPeerDomainName(backend->ssl_ctx, hostname,
     strlen(hostname));
 
     if(err != noErr) {
@@ -1786,7 +1788,7 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
      higher priority, but it's probably better that we not connect at all than
      to give the user a false sense of security if the server only supports
      insecure ciphers. (Note: We don't care about SSLv2-only ciphers.) */
-  err = SSLGetNumberSupportedCiphers(BACKEND->ssl_ctx, &all_ciphers_count);
+  err = SSLGetNumberSupportedCiphers(backend->ssl_ctx, &all_ciphers_count);
   if(err != noErr) {
     failf(data, "SSL: SSLGetNumberSupportedCiphers() failed: OSStatus %d",
           err);
@@ -1803,7 +1805,7 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
     failf(data, "SSL: Failed to allocate memory for allowed ciphers");
     return CURLE_OUT_OF_MEMORY;
   }
-  err = SSLGetSupportedCiphers(BACKEND->ssl_ctx, all_ciphers,
+  err = SSLGetSupportedCiphers(backend->ssl_ctx, all_ciphers,
                                &all_ciphers_count);
   if(err != noErr) {
     Curl_safefree(all_ciphers);
@@ -1890,7 +1892,7 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
         break;
     }
   }
-  err = SSLSetEnabledCiphers(BACKEND->ssl_ctx, allowed_ciphers,
+  err = SSLSetEnabledCiphers(backend->ssl_ctx, allowed_ciphers,
                              allowed_ciphers_count);
   Curl_safefree(all_ciphers);
   Curl_safefree(allowed_ciphers);
@@ -1903,9 +1905,9 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
   /* We want to enable 1/n-1 when using a CBC cipher unless the user
      specifically doesn't want us doing that: */
   if(SSLSetSessionOption != NULL) {
-    SSLSetSessionOption(BACKEND->ssl_ctx, kSSLSessionOptionSendOneByteRecord,
+    SSLSetSessionOption(backend->ssl_ctx, kSSLSessionOptionSendOneByteRecord,
                       !data->set.ssl.enable_beast);
-    SSLSetSessionOption(BACKEND->ssl_ctx, kSSLSessionOptionFalseStart,
+    SSLSetSessionOption(backend->ssl_ctx, kSSLSessionOptionFalseStart,
                       data->set.ssl.falsestart); /* false start support */
   }
 #endif /* CURL_BUILD_MAC_10_9 || CURL_BUILD_IOS_7 */
@@ -1919,7 +1921,7 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
     if(!Curl_ssl_getsessionid(conn, (void **)&ssl_sessionid,
                               &ssl_sessionid_len, sockindex)) {
       /* we got a session id, use it! */
-      err = SSLSetPeerID(BACKEND->ssl_ctx, ssl_sessionid, ssl_sessionid_len);
+      err = SSLSetPeerID(backend->ssl_ctx, ssl_sessionid, ssl_sessionid_len);
       Curl_ssl_sessionid_unlock(conn);
       if(err != noErr) {
         failf(data, "SSL: SSLSetPeerID() failed: OSStatus %d", err);
@@ -1937,7 +1939,7 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
                 verifypeer, SSL_CONN_CONFIG(verifyhost), hostname, port);
       ssl_sessionid_len = strlen(ssl_sessionid);
 
-      err = SSLSetPeerID(BACKEND->ssl_ctx, ssl_sessionid, ssl_sessionid_len);
+      err = SSLSetPeerID(backend->ssl_ctx, ssl_sessionid, ssl_sessionid_len);
       if(err != noErr) {
         Curl_ssl_sessionid_unlock(conn);
         failf(data, "SSL: SSLSetPeerID() failed: OSStatus %d", err);
@@ -1954,7 +1956,7 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
     }
   }
 
-  err = SSLSetIOFuncs(BACKEND->ssl_ctx, SocketRead, SocketWrite);
+  err = SSLSetIOFuncs(backend->ssl_ctx, SocketRead, SocketWrite);
   if(err != noErr) {
     failf(data, "SSL: SSLSetIOFuncs() failed: OSStatus %d", err);
     return CURLE_SSL_CONNECT_ERROR;
@@ -1964,8 +1966,8 @@ static CURLcode sectransp_connect_step1(struct connectdata *conn,
   /* We need to store the FD in a constant memory address, because
    * SSLSetConnection() will not copy that address. I've found that
    * conn->sock[sockindex] may change on its own. */
-  BACKEND->ssl_sockfd = sockfd;
-  err = SSLSetConnection(BACKEND->ssl_ctx, connssl);
+  backend->ssl_sockfd = sockfd;
+  err = SSLSetConnection(backend->ssl_ctx, connssl);
   if(err != noErr) {
     failf(data, "SSL: SSLSetConnection() failed: %d", err);
     return CURLE_SSL_CONNECT_ERROR;
@@ -2346,6 +2348,7 @@ sectransp_connect_step2(struct connectdata *conn, int sockindex)
 {
   struct Curl_easy *data = conn->data;
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   OSStatus err;
   SSLCipherSuite cipher;
   SSLProtocol protocol = 0;
@@ -2357,12 +2360,12 @@ sectransp_connect_step2(struct connectdata *conn, int sockindex)
               || ssl_connect_2_writing == connssl->connecting_state);
 
   /* Here goes nothing: */
-  err = SSLHandshake(BACKEND->ssl_ctx);
+  err = SSLHandshake(backend->ssl_ctx);
 
   if(err != noErr) {
     switch(err) {
       case errSSLWouldBlock:  /* they're not done with us yet */
-        connssl->connecting_state = BACKEND->ssl_direction ?
+        connssl->connecting_state = backend->ssl_direction ?
             ssl_connect_2_writing : ssl_connect_2_reading;
         return CURLE_OK;
 
@@ -2371,7 +2374,7 @@ sectransp_connect_step2(struct connectdata *conn, int sockindex)
       case -9841:
         if(SSL_CONN_CONFIG(CAfile) && SSL_CONN_CONFIG(verifypeer)) {
           CURLcode result = verify_cert(SSL_CONN_CONFIG(CAfile), data,
-                                        BACKEND->ssl_ctx);
+                                        backend->ssl_ctx);
           if(result)
             return result;
         }
@@ -2580,7 +2583,7 @@ sectransp_connect_step2(struct connectdata *conn, int sockindex)
 
 #ifdef SECTRANSP_PINNEDPUBKEY
     if(data->set.str[STRING_SSL_PINNEDPUBLICKEY_ORIG]) {
-      CURLcode result = pkp_pin_peer_pubkey(data, BACKEND->ssl_ctx,
+      CURLcode result = pkp_pin_peer_pubkey(data, backend->ssl_ctx,
                             data->set.str[STRING_SSL_PINNEDPUBLICKEY_ORIG]);
       if(result) {
         failf(data, "SSL: public key does not match pinned public key!");
@@ -2590,8 +2593,8 @@ sectransp_connect_step2(struct connectdata *conn, int sockindex)
 #endif /* SECTRANSP_PINNEDPUBKEY */
 
     /* Informational message */
-    (void)SSLGetNegotiatedCipher(BACKEND->ssl_ctx, &cipher);
-    (void)SSLGetNegotiatedProtocolVersion(BACKEND->ssl_ctx, &protocol);
+    (void)SSLGetNegotiatedCipher(backend->ssl_ctx, &cipher);
+    (void)SSLGetNegotiatedProtocolVersion(backend->ssl_ctx, &protocol);
     switch(protocol) {
       case kSSLProtocol2:
         infof(data, "SSL 2.0 connection using %s\n",
@@ -2631,7 +2634,7 @@ sectransp_connect_step2(struct connectdata *conn, int sockindex)
       if(__builtin_available(macOS 10.13.4, iOS 11, tvOS 11, *)) {
         CFArrayRef alpnArr = NULL;
         CFStringRef chosenProtocol = NULL;
-        err = SSLCopyALPNProtocols(BACKEND->ssl_ctx, &alpnArr);
+        err = SSLCopyALPNProtocols(backend->ssl_ctx, &alpnArr);
 
         if(err == noErr && alpnArr && CFArrayGetCount(alpnArr) >= 1)
           chosenProtocol = CFArrayGetValueAtIndex(alpnArr, 0);
@@ -2674,19 +2677,20 @@ show_verbose_server_cert(struct connectdata *conn,
 {
   struct Curl_easy *data = conn->data;
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   CFArrayRef server_certs = NULL;
   SecCertificateRef server_cert;
   OSStatus err;
   CFIndex i, count;
   SecTrustRef trust = NULL;
 
-  if(!BACKEND->ssl_ctx)
+  if(!backend->ssl_ctx)
     return;
 
 #if CURL_BUILD_MAC_10_7 || CURL_BUILD_IOS
 #if CURL_BUILD_IOS
 #pragma unused(server_certs)
-  err = SSLCopyPeerTrust(BACKEND->ssl_ctx, &trust);
+  err = SSLCopyPeerTrust(backend->ssl_ctx, &trust);
   /* For some reason, SSLCopyPeerTrust() can return noErr and yet return
      a null trust, so be on guard for that: */
   if(err == noErr && trust) {
@@ -2712,7 +2716,7 @@ show_verbose_server_cert(struct connectdata *conn,
      Lion or later. */
   if(SecTrustEvaluateAsync != NULL) {
 #pragma unused(server_certs)
-    err = SSLCopyPeerTrust(BACKEND->ssl_ctx, &trust);
+    err = SSLCopyPeerTrust(backend->ssl_ctx, &trust);
     /* For some reason, SSLCopyPeerTrust() can return noErr and yet return
        a null trust, so be on guard for that: */
     if(err == noErr && trust) {
@@ -2732,7 +2736,7 @@ show_verbose_server_cert(struct connectdata *conn,
   }
   else {
 #if CURL_SUPPORT_MAC_10_8
-    err = SSLCopyPeerCertificates(BACKEND->ssl_ctx, &server_certs);
+    err = SSLCopyPeerCertificates(backend->ssl_ctx, &server_certs);
     /* Just in case SSLCopyPeerCertificates() returns null too... */
     if(err == noErr && server_certs) {
       count = CFArrayGetCount(server_certs);
@@ -2754,7 +2758,7 @@ show_verbose_server_cert(struct connectdata *conn,
 #endif /* CURL_BUILD_IOS */
 #else
 #pragma unused(trust)
-  err = SSLCopyPeerCertificates(BACKEND->ssl_ctx, &server_certs);
+  err = SSLCopyPeerCertificates(backend->ssl_ctx, &server_certs);
   if(err == noErr) {
     count = CFArrayGetCount(server_certs);
     for(i = 0L ; i < count ; i++) {
@@ -2933,34 +2937,36 @@ static CURLcode Curl_sectransp_connect(struct connectdata *conn, int sockindex)
 static void Curl_sectransp_close(struct connectdata *conn, int sockindex)
 {
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
 
-  if(BACKEND->ssl_ctx) {
-    (void)SSLClose(BACKEND->ssl_ctx);
+  if(backend->ssl_ctx) {
+    (void)SSLClose(backend->ssl_ctx);
 #if CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS
     if(SSLCreateContext != NULL)
-      CFRelease(BACKEND->ssl_ctx);
+      CFRelease(backend->ssl_ctx);
 #if CURL_SUPPORT_MAC_10_8
     else
-      (void)SSLDisposeContext(BACKEND->ssl_ctx);
+      (void)SSLDisposeContext(backend->ssl_ctx);
 #endif  /* CURL_SUPPORT_MAC_10_8 */
 #else
-    (void)SSLDisposeContext(BACKEND->ssl_ctx);
+    (void)SSLDisposeContext(backend->ssl_ctx);
 #endif /* CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS */
-    BACKEND->ssl_ctx = NULL;
+    backend->ssl_ctx = NULL;
   }
-  BACKEND->ssl_sockfd = 0;
+  backend->ssl_sockfd = 0;
 }
 
 static int Curl_sectransp_shutdown(struct connectdata *conn, int sockindex)
 {
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   struct Curl_easy *data = conn->data;
   ssize_t nread;
   int what;
   int rc;
   char buf[120];
 
-  if(!BACKEND->ssl_ctx)
+  if(!backend->ssl_ctx)
     return 0;
 
 #ifndef CURL_DISABLE_FTP
@@ -3033,11 +3039,12 @@ static size_t Curl_sectransp_version(char *buffer, size_t size)
 static int Curl_sectransp_check_cxn(struct connectdata *conn)
 {
   struct ssl_connect_data *connssl = &conn->ssl[FIRSTSOCKET];
+  struct ssl_backend_data *backend = connssl->backend;
   OSStatus err;
   SSLSessionState state;
 
-  if(BACKEND->ssl_ctx) {
-    err = SSLGetSessionState(BACKEND->ssl_ctx, &state);
+  if(backend->ssl_ctx) {
+    err = SSLGetSessionState(backend->ssl_ctx, &state);
     if(err == noErr)
       return state == kSSLConnected || state == kSSLHandshake;
     return -1;
@@ -3049,11 +3056,12 @@ static bool Curl_sectransp_data_pending(const struct connectdata *conn,
                                         int connindex)
 {
   const struct ssl_connect_data *connssl = &conn->ssl[connindex];
+  struct ssl_backend_data *backend = connssl->backend;
   OSStatus err;
   size_t buffer;
 
-  if(BACKEND->ssl_ctx) {  /* SSL is in use */
-    err = SSLGetBufferedReadSize(BACKEND->ssl_ctx, &buffer);
+  if(backend->ssl_ctx) {  /* SSL is in use */
+    err = SSLGetBufferedReadSize(backend->ssl_ctx, &buffer);
     if(err == noErr)
       return buffer > 0UL;
     return false;
@@ -3119,6 +3127,7 @@ static ssize_t sectransp_send(struct connectdata *conn,
 {
   /*struct Curl_easy *data = conn->data;*/
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   size_t processed = 0UL;
   OSStatus err;
 
@@ -3137,15 +3146,15 @@ static ssize_t sectransp_send(struct connectdata *conn,
      over again with no new data until it quits returning errSSLWouldBlock. */
 
   /* Do we have buffered data to write from the last time we were called? */
-  if(BACKEND->ssl_write_buffered_length) {
+  if(backend->ssl_write_buffered_length) {
     /* Write the buffered data: */
-    err = SSLWrite(BACKEND->ssl_ctx, NULL, 0UL, &processed);
+    err = SSLWrite(backend->ssl_ctx, NULL, 0UL, &processed);
     switch(err) {
       case noErr:
         /* processed is always going to be 0 because we didn't write to
            the buffer, so return how much was written to the socket */
-        processed = BACKEND->ssl_write_buffered_length;
-        BACKEND->ssl_write_buffered_length = 0UL;
+        processed = backend->ssl_write_buffered_length;
+        backend->ssl_write_buffered_length = 0UL;
         break;
       case errSSLWouldBlock: /* argh, try again */
         *curlcode = CURLE_AGAIN;
@@ -3158,13 +3167,13 @@ static ssize_t sectransp_send(struct connectdata *conn,
   }
   else {
     /* We've got new data to write: */
-    err = SSLWrite(BACKEND->ssl_ctx, mem, len, &processed);
+    err = SSLWrite(backend->ssl_ctx, mem, len, &processed);
     if(err != noErr) {
       switch(err) {
         case errSSLWouldBlock:
           /* Data was buffered but not sent, we have to tell the caller
              to try sending again, and remember how much was buffered */
-          BACKEND->ssl_write_buffered_length = len;
+          backend->ssl_write_buffered_length = len;
           *curlcode = CURLE_AGAIN;
           return -1L;
         default:
@@ -3185,11 +3194,12 @@ static ssize_t sectransp_recv(struct connectdata *conn,
 {
   /*struct Curl_easy *data = conn->data;*/
   struct ssl_connect_data *connssl = &conn->ssl[num];
+  struct ssl_backend_data *backend = connssl->backend;
   size_t processed = 0UL;
   OSStatus err;
 
   again:
-  err = SSLRead(BACKEND->ssl_ctx, buf, buffersize, &processed);
+  err = SSLRead(backend->ssl_ctx, buf, buffersize, &processed);
 
   if(err != noErr) {
     switch(err) {
@@ -3215,7 +3225,7 @@ static ssize_t sectransp_recv(struct connectdata *conn,
       case -9841:
         if(SSL_CONN_CONFIG(CAfile) && SSL_CONN_CONFIG(verifypeer)) {
           CURLcode result = verify_cert(SSL_CONN_CONFIG(CAfile), conn->data,
-                                        BACKEND->ssl_ctx);
+                                        backend->ssl_ctx);
           if(result)
             return result;
         }
@@ -3233,8 +3243,9 @@ static ssize_t sectransp_recv(struct connectdata *conn,
 static void *Curl_sectransp_get_internals(struct ssl_connect_data *connssl,
                                           CURLINFO info UNUSED_PARAM)
 {
+  struct ssl_backend_data *backend = connssl->backend;
   (void)info;
-  return BACKEND->ssl_ctx;
+  return backend->ssl_ctx;
 }
 
 const struct Curl_ssl Curl_ssl_sectransp = {
diff --git a/lib/vtls/vtls.c b/lib/vtls/vtls.c
index dfefa1bd..f1b52522 100644
--- a/lib/vtls/vtls.c
+++ b/lib/vtls/vtls.c
@@ -174,6 +174,9 @@ int Curl_ssl_init(void)
   return Curl_ssl->init();
 }
 
+#if defined(CURL_WITH_MULTI_SSL)
+static const struct Curl_ssl Curl_ssl_multi;
+#endif
 
 /* Global cleanup */
 void Curl_ssl_cleanup(void)
@@ -181,6 +184,9 @@ void Curl_ssl_cleanup(void)
   if(init_ssl) {
     /* only cleanup if we did a previous init */
     Curl_ssl->cleanup();
+#if defined(CURL_WITH_MULTI_SSL)
+    Curl_ssl = &Curl_ssl_multi;
+#endif
     init_ssl = FALSE;
   }
 }
@@ -489,6 +495,7 @@ CURLcode Curl_ssl_addsessionid(struct connectdata *conn,
   store->scheme = conn->handler->scheme;
 
   if(!Curl_clone_primary_ssl_config(ssl_config, &store->ssl_config)) {
+    Curl_free_primary_ssl_config(&store->ssl_config);
     store->sessionid = NULL; /* let caller free sessionid */
     free(clone_host);
     free(clone_conn_to_host);
diff --git a/lib/vtls/wolfssl.c b/lib/vtls/wolfssl.c
index 8c2d3f4a..5040b059 100644
--- a/lib/vtls/wolfssl.c
+++ b/lib/vtls/wolfssl.c
@@ -96,12 +96,9 @@ struct ssl_backend_data {
   SSL*     handle;
 };
 
-#define BACKEND connssl->backend
-
 static Curl_recv wolfssl_recv;
 static Curl_send wolfssl_send;
 
-
 static int do_file_type(const char *type)
 {
   if(!type || !type[0])
@@ -124,6 +121,7 @@ wolfssl_connect_step1(struct connectdata *conn,
   char *ciphers;
   struct Curl_easy *data = conn->data;
   struct ssl_connect_data* connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   SSL_METHOD* req_method = NULL;
   curl_socket_t sockfd = conn->sock[sockindex];
 #ifdef HAVE_SNI
@@ -203,11 +201,11 @@ wolfssl_connect_step1(struct connectdata *conn,
     return CURLE_OUT_OF_MEMORY;
   }
 
-  if(BACKEND->ctx)
-    SSL_CTX_free(BACKEND->ctx);
-  BACKEND->ctx = SSL_CTX_new(req_method);
+  if(backend->ctx)
+    SSL_CTX_free(backend->ctx);
+  backend->ctx = SSL_CTX_new(req_method);
 
-  if(!BACKEND->ctx) {
+  if(!backend->ctx) {
     failf(data, "SSL: couldn't create a context!");
     return CURLE_OUT_OF_MEMORY;
   }
@@ -222,11 +220,11 @@ wolfssl_connect_step1(struct connectdata *conn,
      * defaults to TLS 1.1) so we have this short circuit evaluation to find
      * the minimum supported TLS version.
     */
-    if((wolfSSL_CTX_SetMinVersion(BACKEND->ctx, WOLFSSL_TLSV1) != 1) &&
-       (wolfSSL_CTX_SetMinVersion(BACKEND->ctx, WOLFSSL_TLSV1_1) != 1) &&
-       (wolfSSL_CTX_SetMinVersion(BACKEND->ctx, WOLFSSL_TLSV1_2) != 1)
+    if((wolfSSL_CTX_SetMinVersion(backend->ctx, WOLFSSL_TLSV1) != 1) &&
+       (wolfSSL_CTX_SetMinVersion(backend->ctx, WOLFSSL_TLSV1_1) != 1) &&
+       (wolfSSL_CTX_SetMinVersion(backend->ctx, WOLFSSL_TLSV1_2) != 1)
 #ifdef WOLFSSL_TLS13
-       && (wolfSSL_CTX_SetMinVersion(BACKEND->ctx, WOLFSSL_TLSV1_3) != 1)
+       && (wolfSSL_CTX_SetMinVersion(backend->ctx, WOLFSSL_TLSV1_3) != 1)
 #endif
       ) {
       failf(data, "SSL: couldn't set the minimum protocol version");
@@ -238,7 +236,7 @@ wolfssl_connect_step1(struct connectdata *conn,
 
   ciphers = SSL_CONN_CONFIG(cipher_list);
   if(ciphers) {
-    if(!SSL_CTX_set_cipher_list(BACKEND->ctx, ciphers)) {
+    if(!SSL_CTX_set_cipher_list(backend->ctx, ciphers)) {
       failf(data, "failed setting cipher list: %s", ciphers);
       return CURLE_SSL_CIPHER;
     }
@@ -248,7 +246,7 @@ wolfssl_connect_step1(struct connectdata *conn,
 #ifndef NO_FILESYSTEM
   /* load trusted cacert */
   if(SSL_CONN_CONFIG(CAfile)) {
-    if(1 != SSL_CTX_load_verify_locations(BACKEND->ctx,
+    if(1 != SSL_CTX_load_verify_locations(backend->ctx,
                                       SSL_CONN_CONFIG(CAfile),
                                       SSL_CONN_CONFIG(CApath))) {
       if(SSL_CONN_CONFIG(verifypeer)) {
@@ -285,7 +283,7 @@ wolfssl_connect_step1(struct connectdata *conn,
   if(SSL_SET_OPTION(cert) && SSL_SET_OPTION(key)) {
     int file_type = do_file_type(SSL_SET_OPTION(cert_type));
 
-    if(SSL_CTX_use_certificate_file(BACKEND->ctx, SSL_SET_OPTION(cert),
+    if(SSL_CTX_use_certificate_file(backend->ctx, SSL_SET_OPTION(cert),
                                      file_type) != 1) {
       failf(data, "unable to use client certificate (no key or wrong pass"
             " phrase?)");
@@ -293,7 +291,7 @@ wolfssl_connect_step1(struct connectdata *conn,
     }
 
     file_type = do_file_type(SSL_SET_OPTION(key_type));
-    if(SSL_CTX_use_PrivateKey_file(BACKEND->ctx, SSL_SET_OPTION(key),
+    if(SSL_CTX_use_PrivateKey_file(backend->ctx, SSL_SET_OPTION(key),
                                     file_type) != 1) {
       failf(data, "unable to set private key");
       return CURLE_SSL_CONNECT_ERROR;
@@ -305,7 +303,7 @@ wolfssl_connect_step1(struct connectdata *conn,
    * fail to connect if the verification fails, or if it should continue
    * anyway. In the latter case the result of the verification is checked with
    * SSL_get_verify_result() below. */
-  SSL_CTX_set_verify(BACKEND->ctx,
+  SSL_CTX_set_verify(backend->ctx,
                      SSL_CONN_CONFIG(verifypeer)?SSL_VERIFY_PEER:
                                                  SSL_VERIFY_NONE,
                      NULL);
@@ -324,7 +322,7 @@ wolfssl_connect_step1(struct connectdata *conn,
 #ifdef ENABLE_IPV6
        (0 == Curl_inet_pton(AF_INET6, hostname, &addr6)) &&
 #endif
-       (wolfSSL_CTX_UseSNI(BACKEND->ctx, WOLFSSL_SNI_HOST_NAME, hostname,
+       (wolfSSL_CTX_UseSNI(backend->ctx, WOLFSSL_SNI_HOST_NAME, hostname,
                           (unsigned short)hostname_len) != 1)) {
       infof(data, "WARNING: failed to configure server name indication (SNI) "
             "TLS extension\n");
@@ -334,7 +332,7 @@ wolfssl_connect_step1(struct connectdata *conn,
 
   /* give application a chance to interfere with SSL set up. */
   if(data->set.ssl.fsslctx) {
-    CURLcode result = (*data->set.ssl.fsslctx)(data, BACKEND->ctx,
+    CURLcode result = (*data->set.ssl.fsslctx)(data, backend->ctx,
                                                data->set.ssl.fsslctxp);
     if(result) {
       failf(data, "error signaled by ssl ctx callback");
@@ -352,10 +350,10 @@ wolfssl_connect_step1(struct connectdata *conn,
 #endif
 
   /* Let's make an SSL structure */
-  if(BACKEND->handle)
-    SSL_free(BACKEND->handle);
-  BACKEND->handle = SSL_new(BACKEND->ctx);
-  if(!BACKEND->handle) {
+  if(backend->handle)
+    SSL_free(backend->handle);
+  backend->handle = SSL_new(backend->ctx);
+  if(!backend->handle) {
     failf(data, "SSL: couldn't create a context (handle)!");
     return CURLE_OUT_OF_MEMORY;
   }
@@ -378,7 +376,7 @@ wolfssl_connect_step1(struct connectdata *conn,
     strcpy(protocols + strlen(protocols), ALPN_HTTP_1_1);
     infof(data, "ALPN, offering %s\n", ALPN_HTTP_1_1);
 
-    if(wolfSSL_UseALPN(BACKEND->handle, protocols,
+    if(wolfSSL_UseALPN(backend->handle, protocols,
                        (unsigned)strlen(protocols),
                        WOLFSSL_ALPN_CONTINUE_ON_MISMATCH) != SSL_SUCCESS) {
       failf(data, "SSL: failed setting ALPN protocols");
@@ -394,11 +392,11 @@ wolfssl_connect_step1(struct connectdata *conn,
     Curl_ssl_sessionid_lock(conn);
     if(!Curl_ssl_getsessionid(conn, &ssl_sessionid, NULL, sockindex)) {
       /* we got a session id, use it! */
-      if(!SSL_set_session(BACKEND->handle, ssl_sessionid)) {
+      if(!SSL_set_session(backend->handle, ssl_sessionid)) {
         char error_buffer[WOLFSSL_MAX_ERROR_SZ];
         Curl_ssl_sessionid_unlock(conn);
         failf(data, "SSL: SSL_set_session failed: %s",
-              ERR_error_string(SSL_get_error(BACKEND->handle, 0),
+              ERR_error_string(SSL_get_error(backend->handle, 0),
                                error_buffer));
         return CURLE_SSL_CONNECT_ERROR;
       }
@@ -409,7 +407,7 @@ wolfssl_connect_step1(struct connectdata *conn,
   }
 
   /* pass the raw socket into the SSL layer */
-  if(!SSL_set_fd(BACKEND->handle, (int)sockfd)) {
+  if(!SSL_set_fd(backend->handle, (int)sockfd)) {
     failf(data, "SSL: SSL_set_fd failed");
     return CURLE_SSL_CONNECT_ERROR;
   }
@@ -426,6 +424,7 @@ wolfssl_connect_step2(struct connectdata *conn,
   int ret = -1;
   struct Curl_easy *data = conn->data;
   struct ssl_connect_data* connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   const char * const hostname = SSL_IS_PROXY() ? conn->http_proxy.host.name :
     conn->host.name;
   const char * const dispname = SSL_IS_PROXY() ?
@@ -439,15 +438,15 @@ wolfssl_connect_step2(struct connectdata *conn,
 
   /* Enable RFC2818 checks */
   if(SSL_CONN_CONFIG(verifyhost)) {
-    ret = wolfSSL_check_domain_name(BACKEND->handle, hostname);
+    ret = wolfSSL_check_domain_name(backend->handle, hostname);
     if(ret == SSL_FAILURE)
       return CURLE_OUT_OF_MEMORY;
   }
 
-  ret = SSL_connect(BACKEND->handle);
+  ret = SSL_connect(backend->handle);
   if(ret != 1) {
     char error_buffer[WOLFSSL_MAX_ERROR_SZ];
-    int  detail = SSL_get_error(BACKEND->handle, ret);
+    int  detail = SSL_get_error(backend->handle, ret);
 
     if(SSL_ERROR_WANT_READ == detail) {
       connssl->connecting_state = ssl_connect_2_reading;
@@ -516,7 +515,7 @@ wolfssl_connect_step2(struct connectdata *conn,
     curl_asn1Element *pubkey;
     CURLcode result;
 
-    x509 = SSL_get_peer_certificate(BACKEND->handle);
+    x509 = SSL_get_peer_certificate(backend->handle);
     if(!x509) {
       failf(data, "SSL: failed retrieving server certificate");
       return CURLE_SSL_PINNEDPUBKEYNOTMATCH;
@@ -558,7 +557,7 @@ wolfssl_connect_step2(struct connectdata *conn,
     char *protocol = NULL;
     unsigned short protocol_len = 0;
 
-    rc = wolfSSL_ALPN_GetProtocol(BACKEND->handle, &protocol, &protocol_len);
+    rc = wolfSSL_ALPN_GetProtocol(backend->handle, &protocol, &protocol_len);
 
     if(rc == SSL_SUCCESS) {
       infof(data, "ALPN, server accepted to use %.*s\n", protocol_len,
@@ -592,8 +591,8 @@ wolfssl_connect_step2(struct connectdata *conn,
   connssl->connecting_state = ssl_connect_3;
 #if (LIBWOLFSSL_VERSION_HEX >= 0x03009010)
   infof(data, "SSL connection using %s / %s\n",
-        wolfSSL_get_version(BACKEND->handle),
-        wolfSSL_get_cipher_name(BACKEND->handle));
+        wolfSSL_get_version(backend->handle),
+        wolfSSL_get_cipher_name(backend->handle));
 #else
   infof(data, "SSL connected\n");
 #endif
@@ -609,6 +608,7 @@ wolfssl_connect_step3(struct connectdata *conn,
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
 
   DEBUGASSERT(ssl_connect_3 == connssl->connecting_state);
 
@@ -617,7 +617,7 @@ wolfssl_connect_step3(struct connectdata *conn,
     SSL_SESSION *our_ssl_sessionid;
     void *old_ssl_sessionid = NULL;
 
-    our_ssl_sessionid = SSL_get_session(BACKEND->handle);
+    our_ssl_sessionid = SSL_get_session(backend->handle);
 
     Curl_ssl_sessionid_lock(conn);
     incache = !(Curl_ssl_getsessionid(conn, &old_ssl_sessionid, NULL,
@@ -655,12 +655,13 @@ static ssize_t wolfssl_send(struct connectdata *conn,
                            CURLcode *curlcode)
 {
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
   char error_buffer[WOLFSSL_MAX_ERROR_SZ];
-  int  memlen = (len > (size_t)INT_MAX) ? INT_MAX : (int)len;
-  int  rc     = SSL_write(BACKEND->handle, mem, memlen);
+  int memlen = (len > (size_t)INT_MAX) ? INT_MAX : (int)len;
+  int rc = SSL_write(backend->handle, mem, memlen);
 
   if(rc < 0) {
-    int err = SSL_get_error(BACKEND->handle, rc);
+    int err = SSL_get_error(backend->handle, rc);
 
     switch(err) {
     case SSL_ERROR_WANT_READ:
@@ -682,31 +683,33 @@ static ssize_t wolfssl_send(struct connectdata *conn,
 static void Curl_wolfssl_close(struct connectdata *conn, int sockindex)
 {
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
 
-  if(BACKEND->handle) {
-    (void)SSL_shutdown(BACKEND->handle);
-    SSL_free(BACKEND->handle);
-    BACKEND->handle = NULL;
+  if(backend->handle) {
+    (void)SSL_shutdown(backend->handle);
+    SSL_free(backend->handle);
+    backend->handle = NULL;
   }
-  if(BACKEND->ctx) {
-    SSL_CTX_free(BACKEND->ctx);
-    BACKEND->ctx = NULL;
+  if(backend->ctx) {
+    SSL_CTX_free(backend->ctx);
+    backend->ctx = NULL;
   }
 }
 
 static ssize_t wolfssl_recv(struct connectdata *conn,
-                           int num,
-                           char *buf,
-                           size_t buffersize,
-                           CURLcode *curlcode)
+                            int num,
+                            char *buf,
+                            size_t buffersize,
+                            CURLcode *curlcode)
 {
   struct ssl_connect_data *connssl = &conn->ssl[num];
+  struct ssl_backend_data *backend = connssl->backend;
   char error_buffer[WOLFSSL_MAX_ERROR_SZ];
-  int  buffsize = (buffersize > (size_t)INT_MAX) ? INT_MAX : (int)buffersize;
-  int  nread    = SSL_read(BACKEND->handle, buf, buffsize);
+  int buffsize = (buffersize > (size_t)INT_MAX) ? INT_MAX : (int)buffersize;
+  int nread = SSL_read(backend->handle, buf, buffsize);
 
   if(nread < 0) {
-    int err = SSL_get_error(BACKEND->handle, nread);
+    int err = SSL_get_error(backend->handle, nread);
 
     switch(err) {
     case SSL_ERROR_ZERO_RETURN: /* no more data */
@@ -758,11 +761,12 @@ static void Curl_wolfssl_cleanup(void)
 
 
 static bool Curl_wolfssl_data_pending(const struct connectdata* conn,
-                                     int connindex)
+                                      int connindex)
 {
   const struct ssl_connect_data *connssl = &conn->ssl[connindex];
-  if(BACKEND->handle)   /* SSL is in use */
-    return (0 != SSL_pending(BACKEND->handle)) ? TRUE : FALSE;
+  struct ssl_backend_data *backend = connssl->backend;
+  if(backend->handle)   /* SSL is in use */
+    return (0 != SSL_pending(backend->handle)) ? TRUE : FALSE;
   else
     return FALSE;
 }
@@ -776,10 +780,11 @@ static int Curl_wolfssl_shutdown(struct connectdata *conn, int sockindex)
 {
   int retval = 0;
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct ssl_backend_data *backend = connssl->backend;
 
-  if(BACKEND->handle) {
-    SSL_free(BACKEND->handle);
-    BACKEND->handle = NULL;
+  if(backend->handle) {
+    SSL_free(backend->handle);
+    backend->handle = NULL;
   }
   return retval;
 }
@@ -950,10 +955,11 @@ static CURLcode Curl_wolfssl_sha256sum(const unsigned char *tmp, /* input */
 }
 
 static void *Curl_wolfssl_get_internals(struct ssl_connect_data *connssl,
-                                       CURLINFO info UNUSED_PARAM)
+                                        CURLINFO info UNUSED_PARAM)
 {
+  struct ssl_backend_data *backend = connssl->backend;
   (void)info;
-  return BACKEND->handle;
+  return backend->handle;
 }
 
 const struct Curl_ssl Curl_ssl_wolfssl = {
diff --git a/lib/warnless.h b/lib/warnless.h
index ea4c4395..ab78f944 100644
--- a/lib/warnless.h
+++ b/lib/warnless.h
@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -94,19 +94,6 @@ unsigned short curlx_htons(unsigned short usnum);
 
 unsigned short curlx_ntohs(unsigned short usnum);
 
-#ifndef BUILDING_WARNLESS_C
-#  undef  FD_ISSET
-#  define FD_ISSET(a,b) curlx_FD_ISSET((a),(b))
-#  undef  FD_SET
-#  define FD_SET(a,b)   curlx_FD_SET((a),(b))
-#  undef  FD_ZERO
-#  define FD_ZERO(a)    curlx_FD_ZERO((a))
-#  undef  htons
-#  define htons(a)      curlx_htons((a))
-#  undef  ntohs
-#  define ntohs(a)      curlx_ntohs((a))
-#endif
-
 #endif /* __INTEL_COMPILER && __unix__ */
 
 #endif /* HEADER_CURL_WARNLESS_H */