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author | Daniel Drown <dan-android@drown.org> | 2012-03-23 10:42:54 -0500 |
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committer | JP Abgrall <jpa@google.com> | 2012-11-12 15:59:12 -0800 |
commit | a45056e35c1af2a0f0a6eed258fd5fdf4846a79f (patch) | |
tree | 5dd035946e9ab1201289292f7343af3230a26433 /dns64.c | |
parent | 62ea9b6658a4c2116eeb6450c8244269448e79aa (diff) | |
download | android_external_android-clat-a45056e35c1af2a0f0a6eed258fd5fdf4846a79f.tar.gz android_external_android-clat-a45056e35c1af2a0f0a6eed258fd5fdf4846a79f.tar.bz2 android_external_android-clat-a45056e35c1af2a0f0a6eed258fd5fdf4846a79f.zip |
android clat service
This software provides the nat 4->6 translation needed for the "clat" part of
the 464xlat standard. It is needed for better IPv4 application support while
on an IPv6-only mobile network connection using 464xlat's nat64 (such as
T-Mobile's IPv6 trial).
A general diagram of how 464xlat works:
http://dan.drown.org/android/clat/Clat-Plat.png
Depends-on: I2392f8127dcd90d16b0f20ff31bcc5aa096db464
Change-Id: If2bc6916fc66fd4bca7cc241c83cfae839b82e15
Signed-off-by: Daniel Drown <dan-android@drown.org>
Diffstat (limited to 'dns64.c')
-rw-r--r-- | dns64.c | 91 |
1 files changed, 91 insertions, 0 deletions
@@ -0,0 +1,91 @@ +/* + * Copyright 2011 Daniel Drown + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + * + * dns64.c - find the nat64 prefix with a dns64 lookup + */ + +#include <sys/socket.h> +#include <netinet/in.h> +#include <arpa/inet.h> +#include <netdb.h> +#include <strings.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> + +#include "dns64.h" +#include "logging.h" + +/* function: plat_prefix + * looks up an ipv4-only hostname and looks for a nat64 /96 prefix, returns 1 on success, 0 on temporary failure, -1 on permanent failure + * ipv4_name - name to lookup + * prefix - the plat /96 prefix + */ +int plat_prefix(const char *ipv4_name, struct in6_addr *prefix) { + struct addrinfo hints, *result, *p; + int status, plat_addr_set, ipv4_records, ipv6_records; + struct in6_addr plat_addr, this_plat_addr; + struct sockaddr_in6 *this_addr; + + result = NULL; + plat_addr_set = 0; + ipv4_records = ipv6_records = 0; + + bzero(&hints, sizeof(hints)); + hints.ai_family = AF_UNSPEC; + status = getaddrinfo(ipv4_name, NULL, &hints, &result); + if(status != 0) { + logmsg(ANDROID_LOG_ERROR,"plat_prefix/dns(%s) status = %d/%s\n", ipv4_name, status, gai_strerror(status)); + return 0; + } + + for(p = result; p; p = p->ai_next) { + if(p->ai_family == AF_INET) { + ipv4_records++; + continue; + } + if(p->ai_family != AF_INET6) { + logmsg(ANDROID_LOG_WARN,"plat_prefix/unexpected address family: %d\n", p->ai_family); + continue; + } + ipv6_records++; + this_addr = (struct sockaddr_in6 *)p->ai_addr; + this_plat_addr = this_addr->sin6_addr; + this_plat_addr.s6_addr32[3] = 0; + + if(!plat_addr_set) { + plat_addr = this_plat_addr; + plat_addr_set = 1; + continue; + } + + if(!IN6_ARE_ADDR_EQUAL(&plat_addr, &this_plat_addr)) { + char plat_addr_str[INET6_ADDRSTRLEN], this_plat_addr_str[INET6_ADDRSTRLEN]; + logmsg(ANDROID_LOG_ERROR,"plat_prefix/two different plat addrs = %s,%s", + inet_ntop(AF_INET6, &plat_addr, plat_addr_str, sizeof(plat_addr_str)), + inet_ntop(AF_INET6, &this_plat_addr, this_plat_addr_str, sizeof(this_plat_addr_str)) + ); + } + } + if(result != NULL) { + freeaddrinfo(result); + } + if(ipv4_records > 0 && ipv6_records == 0) { + logmsg(ANDROID_LOG_WARN,"plat_prefix/no dns64 detected\n"); + return -1; + } + *prefix = plat_addr; + return 1; +} |