Packet Location Interface

13 files changed, 475 insertions, 5 deletions

diff --git a/Makefile.am b/Makefile.am
index 01f9879..e1c47b9 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -6,6 +6,9 @@ SUBDIRS = include lib src doc
 
 pkgconfig_DATA = libnl-2.0.pc
 
+sysconfdir = @sysconfdir@/libnl
+sysconf_DATA = etc/pktloc
+
 .PHONY: cscope
 cscope:
 	cscope -b -q -R -Iinclude -slib -ssrc;
diff --git a/configure.in b/configure.in
index 02b5119..1fcdb64 100644
--- a/configure.in
+++ b/configure.in
@@ -6,7 +6,7 @@
 #	License as published by the Free Software Foundation version 2.1
 #	of the License.
 #
-# Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
+# Copyright (c) 2003-2010 Thomas Graf <tgraf@suug.ch>
 #
 
 AC_INIT(libnl, 2.0, tgraf@suug.ch)
@@ -18,6 +18,8 @@ AC_PROG_CC
 AM_PROG_CC_C_O
 AC_PROG_INSTALL
 AM_PROG_LIBTOOL
+AM_PROG_LEX
+AC_PROG_YACC
 
 AC_C_CONST
 AC_C_INLINE
diff --git a/etc/pktloc b/etc/pktloc
new file mode 100644
index 0000000..db36d40
--- /dev/null
+++ b/etc/pktloc
@@ -0,0 +1,44 @@
+#
+# Location definitions for packet matching
+#
+
+# name		alignment	offset		mask
+ip.version	u8		net+0		0xF0
+ip.hdrlen	u8		net+0		0x0F
+ip.diffserv	u8		net+1
+ip.length	u16		net+2
+ip.id		u16		net+4
+ip.df		u8		net+6		0x40
+ip.mf		u8		net+6		0x20
+ip.offset	u16		net+6		0x1FFF
+ip.ttl		u8		net+8
+ip.proto	u8		net+9
+ip.chksum	u16		net+10
+ip.src		u32		net+12
+ip.dst		u32		net+16
+
+
+#
+# Transmission Control Protocol (TCP)
+#
+# name		alignment	offset		mask
+tcp.sport	u16		tcp+0
+tcp.dport	u16		tcp+2
+tcp.seq		u32		tcp+4
+tcp.ack		u32		tcp+8
+tcp.off		u8		tcp+12		0xF0
+tcp.reserved	u8		tcp+12		0x0F
+# FLAGS
+tcp.win		u16		tcp+14
+tcp.csum	u16		tcp+16
+tcp.urg		u16		tcp+18
+tcp.opts	u32		tcp+20
+
+#
+# User Datagram Protocol (UDP)
+#
+# name		alignment	offset		mask
+udp.sport	u16		tcp+0
+udp.dport	u16		tcp+2
+udp.length	u16		tcp+4
+udp.csum	u16		tcp+6
diff --git a/include/netlink-local.h b/include/netlink-local.h
index 1fafb51..e0c79db 100644
--- a/include/netlink-local.h
+++ b/include/netlink-local.h
@@ -23,6 +23,7 @@
 #include <stdarg.h>
 #include <ctype.h>
 #include <sys/types.h>
+#include <sys/stat.h>
 #include <sys/socket.h>
 #include <inttypes.h>
 #include <assert.h>
diff --git a/include/netlink/errno.h b/include/netlink/errno.h
index 0b43da0..c8a376e 100644
--- a/include/netlink/errno.h
+++ b/include/netlink/errno.h
@@ -45,8 +45,9 @@ extern "C" {
 #define NLE_PROTO_MISMATCH	26
 #define NLE_NOACCESS		27
 #define NLE_PERM		28
+#define NLE_PKTLOC_FILE		29
 
-#define NLE_MAX			NLE_PERM
+#define NLE_MAX			NLE_PKTLOC_FILE
 
 extern const char *	nl_geterror(int);
 extern void		nl_perror(int, const char *);
diff --git a/include/netlink/route/pktloc.h b/include/netlink/route/pktloc.h
new file mode 100644
index 0000000..28e1dc2
--- /dev/null
+++ b/include/netlink/route/pktloc.h
@@ -0,0 +1,44 @@
+/*
+ * netlink/route/pktloc.h         Packet Location Aliasing
+ *
+ *	This library is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU Lesser General Public
+ *	License as published by the Free Software Foundation version 2.1
+ *	of the License.
+ *
+ * Copyright (c) 2010 Thomas Graf <tgraf@suug.ch>
+ */
+
+#ifndef NETLINK_PKTLOC_H_
+#define NETLINK_PKTLOC_H_
+
+#include <netlink/netlink.h>
+#include <netlink/cache.h>
+#include <netlink/route/tc.h>
+
+#include <linux/tc_ematch/tc_em_cmp.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct rtnl_pktloc
+{
+	char *			name;
+	uint8_t			align:4;
+	uint8_t			layer:4;
+	uint8_t			flags;
+	uint16_t		offset;
+	uint32_t		mask;
+
+	struct nl_list_head	list;
+};
+
+extern int rtnl_pktloc_lookup(const char *, struct rtnl_pktloc **);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/lib/Makefile.am b/lib/Makefile.am
index 1c2ae99..082408c 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -1,6 +1,6 @@
 # -*- Makefile -*-
 
-AM_CFLAGS  = -Wall -I${top_srcdir}/include -D_GNU_SOURCE
+AM_CFLAGS  = -Wall -I${top_srcdir}/include -D_GNU_SOURCE -DSYSCONFDIR=\"$(sysconfdir)/libnl\"
 
 lib_LTLIBRARIES = \
 	libnl.la libnl-genl.la libnl-route.la libnl-nf.la
@@ -23,6 +23,19 @@ libnl_nf_la_SOURCES = \
 	netfilter/netfilter.c netfilter/nfnl.c netfilter/queue.c \
 	netfilter/queue_msg.c netfilter/queue_msg_obj.c netfilter/queue_obj.c
 
+BUILT_SOURCES = route/pktloc_syntax.h
+CLEANFILES = \
+	route/pktloc_grammar.c route/pktloc_grammar.h \
+	route/pktloc_syntax.c route/pktloc_syntax.h
+
+# Hack to avoid using ylwrap. It does not function correctly in combination
+# with --header-file=
+route/pktloc_grammar.c: route/pktloc_grammar.l
+	$(LEX) --header-file=route/pktloc_grammar.h $(LFLAGS) -o $@ $^
+
+route/pktloc_syntax.c: route/pktloc_syntax.y
+	$(YACC) -d $(YFLAGS) -o $@ $^
+
 libnl_route_la_LDFLAGS = -version-info 2:0:0
 libnl_route_la_LIBADD  = libnl.la
 libnl_route_la_SOURCES = \
@@ -40,4 +53,6 @@ libnl_route_la_SOURCES = \
 	route/sch/fifo.c route/sch/htb.c route/sch/netem.c route/sch/prio.c \
 	route/sch/red.c route/sch/sfq.c route/sch/tbf.c \
 	\
-	fib_lookup/lookup.c fib_lookup/request.c
+	fib_lookup/lookup.c fib_lookup/request.c \
+	\
+	route/pktloc_syntax.c route/pktloc_grammar.c route/pktloc.c
diff --git a/lib/error.c b/lib/error.c
index b94a235..9a9fac7 100644
--- a/lib/error.c
+++ b/lib/error.c
@@ -42,6 +42,7 @@ static const char *errmsg[NLE_MAX+1] = {
 [NLE_PROTO_MISMATCH]	= "Protocol mismatch",
 [NLE_NOACCESS]		= "No Access",
 [NLE_PERM]		= "Operation not permitted",
+[NLE_PKTLOC_FILE]	= "Unable to open packet location file",
 };
 
 /**
diff --git a/lib/route/pktloc.c b/lib/route/pktloc.c
new file mode 100644
index 0000000..f0d0155
--- /dev/null
+++ b/lib/route/pktloc.c
@@ -0,0 +1,168 @@
+/*
+ * lib/route/pktloc.c     Packet Location Aliasing
+ *
+ *	This library is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License as
+ *	published by the Free Software Foundation version 2 of the License.
+ *
+ * Copyright (c) 2008-2010 Thomas Graf <tgraf@suug.ch>
+ */
+
+/**
+ * @ingroup tc
+ * @defgroup pktloc Packet Location Aliasing
+ * Packet Location Aliasing
+ *
+ * The packet location aliasing interface eases the use of offset definitions
+ * inside packets by allowing them to be referenced by name. Known positions
+ * of protocol fields are stored in a configuration file and associated with
+ * a name for later reference. The configuration file is distributed with the
+ * library and provides a well defined set of definitions for most common
+ * protocol fields.
+ *
+ * @subsection pktloc_examples Examples
+ * @par Example 1.1 Looking up a packet location
+ * @code
+ * struct rtnl_pktloc *loc;
+ *
+ * rtnl_pktloc_lookup("ip.src", &loc);
+ * @endcode
+ * @{
+ */
+
+#include <netlink-local.h>
+#include <netlink-tc.h>
+#include <netlink/netlink.h>
+#include <netlink/utils.h>
+#include <netlink/route/pktloc.h>
+
+#include "pktloc_syntax.h"
+#include "pktloc_grammar.h"
+
+/** @cond */
+#define PKTLOC_NAME_HT_SIZ 256
+
+static struct nl_list_head pktloc_name_ht[PKTLOC_NAME_HT_SIZ];
+
+/* djb2 */
+unsigned int pktloc_hash(const char *str)
+{
+	unsigned long hash = 5381;
+	int c;
+
+	while ((c = *str++))
+		hash = ((hash << 5) + hash) + c; /* hash * 33 + c */
+
+	return hash % PKTLOC_NAME_HT_SIZ;
+}
+
+
+void rtnl_pktloc_add(struct rtnl_pktloc *loc)
+{
+	nl_list_add_tail(&loc->list, &pktloc_name_ht[pktloc_hash(loc->name)]);
+}
+
+extern int pktloc_parse(void *scanner);
+
+/** @endcond */
+
+static void rtnl_pktloc_free(struct rtnl_pktloc *loc)
+{
+	if (!loc)
+		return;
+
+	free(loc->name);
+	free(loc);
+}
+
+static int read_pktlocs(void)
+{
+	YY_BUFFER_STATE buf;
+	yyscan_t scanner = NULL;
+	static time_t last_read;
+	struct stat st = {0};
+	char *path;
+	int i, err;
+	FILE *fd;
+
+	asprintf(&path, "%s/pktloc", SYSCONFDIR);
+
+	/* if stat fails, just try to read the file */
+	if (stat(path, &st) == 0) {
+		/* Don't re-read file if file is unchanged */
+		if (last_read == st.st_mtime)
+			return 0;
+	}
+
+	if (!(fd = fopen(path, "r")))
+		return -NLE_PKTLOC_FILE;
+
+	for (i = 0; i < PKTLOC_NAME_HT_SIZ; i++) {
+		struct rtnl_pktloc *loc, *n;
+
+		nl_list_for_each_entry_safe(loc, n, &pktloc_name_ht[i], list)
+			rtnl_pktloc_free(loc);
+
+		nl_init_list_head(&pktloc_name_ht[i]);
+	}
+
+	if ((err = pktloc_lex_init(&scanner)) < 0)
+		return -NLE_FAILURE;
+
+	buf = pktloc__create_buffer(fd, YY_BUF_SIZE, scanner);
+	pktloc__switch_to_buffer(buf, scanner);
+
+	if ((err = pktloc_parse(scanner)) < 0)
+		return -NLE_FAILURE;
+
+	if (scanner)
+		pktloc_lex_destroy(scanner);
+
+	free(path);
+	last_read = st.st_mtime;
+
+	return 0;
+}
+
+/**
+ * Lookup packet location alias
+ * @arg name		Name of packet location.
+ *
+ * Tries to find a matching packet location alias for the supplied
+ * packet location name.
+ *
+ * The file containing the packet location definitions is automatically
+ * re-read if its modification time has changed since the last call.
+ *
+ * @return 0 on success or a negative error code.
+ * @retval NLE_PKTLOC_FILE Unable to open packet location file.
+ * @retval NLE_OBJ_NOTFOUND No matching packet location alias found.
+ */
+int rtnl_pktloc_lookup(const char *name, struct rtnl_pktloc **result)
+{
+	struct rtnl_pktloc *loc;
+	int hash, err;
+
+	if ((err = read_pktlocs()) < 0)
+		return err;
+
+	hash = pktloc_hash(name);
+	nl_list_for_each_entry(loc, &pktloc_name_ht[hash], list) {
+		if (!strcasecmp(loc->name, name)) {
+			*result = loc;
+			return 0;
+		}
+	}
+
+	return -NLE_OBJ_NOTFOUND;
+}
+
+static int __init pktloc_init(void)
+{
+	int i;
+
+	for (i = 0; i < PKTLOC_NAME_HT_SIZ; i++)
+		nl_init_list_head(&pktloc_name_ht[i]);
+	
+	return 0;
+}
diff --git a/lib/route/pktloc_grammar.l b/lib/route/pktloc_grammar.l
new file mode 100644
index 0000000..f710430
--- /dev/null
+++ b/lib/route/pktloc_grammar.l
@@ -0,0 +1,42 @@
+%{
+ #include <netlink-local.h>
+ #include <netlink-tc.h>
+ #include <netlink/netlink.h>
+ #include <netlink/utils.h>
+ #include <netlink/route/pktloc.h>
+ #include "pktloc_syntax.h"
+%}
+
+%option 8bit
+%option reentrant
+%option warn
+%option noyywrap
+%option nounput
+%option bison-bridge
+%option bison-locations
+%option prefix="pktloc_"
+
+%%
+
+[ \t\r\n]+
+
+"#".*
+
+[[:digit:]]+		|
+0[xX][[:xdigit:]]+	{
+				yylval->i = strtoul(yytext, NULL, 0);
+				return NUMBER;
+			}
+
+"+"			{ return yylval->i = yytext[0]; }
+
+[lL][iI][nN][kK]	{ yylval->i = TCF_LAYER_LINK; return LAYER; }
+[nN][eE][tT]		{ yylval->i = TCF_LAYER_NETWORK; return LAYER; }
+[tT][cC][pP]		{ yylval->i = TCF_LAYER_TRANSPORT; return LAYER; }
+
+[^ \t\r\n+]+		{
+				yylval->s = strdup(yytext);
+				if (yylval->s == NULL)
+					return ERROR;
+				return NAME;
+			}
diff --git a/lib/route/pktloc_syntax.y b/lib/route/pktloc_syntax.y
new file mode 100644
index 0000000..05d609a
--- /dev/null
+++ b/lib/route/pktloc_syntax.y
@@ -0,0 +1,108 @@
+%{
+#include <netlink-local.h>
+#include <netlink-tc.h>
+#include <netlink/netlink.h>
+#include <netlink/utils.h>
+#include <netlink/route/pktloc.h>
+%}
+
+%locations
+%error-verbose
+%define api.pure
+%name-prefix "pktloc_"
+
+%parse-param {void *scanner}
+%lex-param {void *scanner}
+
+%union {
+	struct rtnl_pktloc *l;
+	uint32_t i;
+	char *s;
+}
+
+%{
+extern int pktloc_lex(YYSTYPE *, YYLTYPE *, void *);
+extern void rtnl_pktloc_add(struct rtnl_pktloc *);
+
+static void yyerror(YYLTYPE *locp, void *scanner, const char *msg)
+{
+	/* FIXME */
+}
+%}
+
+%token <i> ERROR NUMBER LAYER
+%token <s> NAME
+
+%type <i> mask layer
+%type <l> location
+
+%destructor { free($$); } NAME
+
+%start input
+
+%%
+
+input:
+	def
+		{ }
+	;
+
+def:
+	/* empty */
+		{ }
+	| location def
+		{ }
+	;
+
+location:
+	NAME NAME layer NUMBER mask
+		{
+			struct rtnl_pktloc *loc;
+
+			if (!(loc = calloc(1, sizeof(*loc)))) {
+				/* FIXME */
+			}
+
+			if (!strcasecmp($2, "u8"))
+				loc->align = TCF_EM_ALIGN_U8;
+			else if (!strcasecmp($2, "h8")) {
+				loc->align = TCF_EM_ALIGN_U8;
+				loc->flags = TCF_EM_CMP_TRANS;
+			} else if (!strcasecmp($2, "u16"))
+				loc->align = TCF_EM_ALIGN_U16;
+			else if (!strcasecmp($2, "h16")) {
+				loc->align = TCF_EM_ALIGN_U16;
+				loc->flags = TCF_EM_CMP_TRANS;
+			} else if (!strcasecmp($2, "u32"))
+				loc->align = TCF_EM_ALIGN_U32;
+			else if (!strcasecmp($2, "h32")) {
+				loc->align = TCF_EM_ALIGN_U32;
+				loc->flags = TCF_EM_CMP_TRANS;
+			}
+			
+			free($2);
+
+			loc->name = $1;
+			loc->layer = $3;
+			loc->offset = $4;
+			loc->mask = $5;
+
+			rtnl_pktloc_add(loc);
+
+			$$ = loc;
+		}
+	;
+
+layer:
+	/* empty */
+		{ $$ = TCF_LAYER_NETWORK; }
+	| LAYER '+' 
+		{ $$ = $1; }
+	;
+
+mask:
+	/* empty */
+		{ $$ = 0; }
+	| NUMBER
+		{ $$ = $1; }
+	;
diff --git a/src/Makefile.am b/src/Makefile.am
index ca37843..4e2b57c 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -20,7 +20,8 @@ noinst_PROGRAMS = \
 	nl-route-add nl-route-delete nl-route-get nl-route-list \
 	nl-fib-lookup \
 	nl-list-caches nl-list-sockets \
-	nl-util-addr
+	nl-util-addr \
+	nl-pktloc-lookup
 
 genl_ctrl_list_SOURCES = genl-ctrl-list.c 
 genl_ctrl_list_LDADD = -lnl-genl -lnl-route
@@ -95,3 +96,6 @@ nl_list_sockets_LDADD = -lnl-route
 
 nl_util_addr_SOURCES = nl-util-addr.c
 nl_util_addr_LDADD = -lnl-route
+
+nl_pktloc_lookup_SOURCES = nl-pktloc-lookup.c
+nl_pktloc_lookup_LDADD = -lnl-route
diff --git a/src/nl-pktloc-lookup.c b/src/nl-pktloc-lookup.c
new file mode 100644
index 0000000..09b04b2
--- /dev/null
+++ b/src/nl-pktloc-lookup.c
@@ -0,0 +1,37 @@
+/*
+ * src/nl-pktloc-lookup.c     Lookup packet location alias
+ *
+ *	This library is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU Lesser General Public
+ *	License as published by the Free Software Foundation version 2.1
+ *	of the License.
+ *
+ * Copyright (c) 2010 Thomas Graf <tgraf@suug.ch>
+ */
+
+#include <netlink/cli/utils.h>
+#include <netlink/route/pktloc.h>
+
+static void print_usage(void)
+{
+	printf("Usage: nl-pktloc-lookup <name>\n");
+	exit(0);
+}
+
+int main(int argc, char *argv[])
+{
+	struct rtnl_pktloc *loc;
+	int err;
+
+	if (argc < 2)
+		print_usage();
+
+	if ((err = rtnl_pktloc_lookup(argv[1], &loc)) < 0)
+		nl_cli_fatal(err, "Unable to lookup packet location: %s",
+			nl_geterror(err));
+
+	printf("%s: %u %u+%u 0x%x %u\n", loc->name, loc->align,
+		loc->layer, loc->offset, loc->mask, loc->flags);
+
+	return 0;
+}