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/* 464xlatcfg.c
*
* Copyright (c) 2015 Steven Barth <cyrus@openwrt.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <netinet/icmp6.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <unistd.h>
#include <stdlib.h>
#include <signal.h>
#include <stdio.h>
#include <netdb.h>
static void sighandler(__attribute__((unused)) int signal)
{
}
int main(int argc, const char *argv[])
{
char buf[INET6_ADDRSTRLEN], prefix[INET6_ADDRSTRLEN + 4];
int pid;
if (argc <= 1) {
fprintf(stderr, "Usage: %s <name> [ifname] [ipv6prefix] [ipv4addr] [ipv6addr]\n", argv[0]);
return 1;
}
snprintf(buf, sizeof(buf), "/var/run/%s.pid", argv[1]);
FILE *fp = fopen(buf, "r");
if (fp) {
fscanf(fp, "%d", &pid);
kill(pid, SIGTERM);
unlink(buf);
fclose(fp);
}
if (!argv[2])
return 0;
if (!argv[3] || !argv[4] || !(fp = fopen(buf, "wx")))
return 1;
signal(SIGTERM, sighandler);
prefix[sizeof(prefix) - 1] = 0;
strncpy(prefix, argv[3], sizeof(prefix) - 1);
if (!prefix[0]) {
struct addrinfo hints = { .ai_family = AF_INET6 }, *res;
if (getaddrinfo("ipv4only.arpa", NULL, &hints, &res) || !res) {
sleep(3);
if (getaddrinfo("ipv4only.arpa", NULL, &hints, &res) || !res)
return 2;
}
struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)res->ai_addr;
inet_ntop(AF_INET6, &sin6->sin6_addr, prefix, sizeof(prefix) - 4);
strcat(prefix, "/96");
freeaddrinfo(res);
}
struct sockaddr_in6 saddr = {.sin6_family = AF_INET6, .sin6_addr = {{{0x20, 0x01, 0x0d, 0xb8}}}};
socklen_t saddrlen = sizeof(saddr);
int sock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
struct icmp6_filter filt;
ICMP6_FILTER_SETBLOCKALL(&filt);
setsockopt(sock, IPPROTO_ICMPV6, ICMP6_FILTER, &filt, sizeof(filt));
setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, argv[2], strlen(argv[2]));
if (connect(sock, (struct sockaddr*)&saddr, sizeof(saddr)) ||
getsockname(sock, (struct sockaddr*)&saddr, &saddrlen))
return 3;
struct ipv6_mreq mreq = {saddr.sin6_addr, if_nametoindex(argv[2])};
if (!argv[5]) {
srandom(mreq.ipv6mr_multiaddr.s6_addr32[0] ^ mreq.ipv6mr_multiaddr.s6_addr32[1] ^
mreq.ipv6mr_multiaddr.s6_addr32[2] ^ mreq.ipv6mr_multiaddr.s6_addr32[3]);
mreq.ipv6mr_multiaddr.s6_addr32[2] = random();
mreq.ipv6mr_multiaddr.s6_addr32[3] = random();
} else if (inet_pton(AF_INET6, argv[5], &mreq.ipv6mr_multiaddr) != 1) {
return 1;
}
if (setsockopt(sock, SOL_IPV6, IPV6_JOIN_ANYCAST, &mreq, sizeof(mreq)))
return 3;
inet_ntop(AF_INET6, &mreq.ipv6mr_multiaddr, buf, sizeof(buf));
fputs(buf, stdout);
fputc('\n', stdout);
fflush(stdout);
FILE *nat46 = fopen("/proc/net/nat46/control", "w");
if (!nat46 || fprintf(nat46, "add %s\nconfig %s local.style NONE local.v4 %s/32 local.v6 %s/128 "
"remote.style RFC6052 remote.v6 %s\n", argv[1], argv[1], argv[4], buf, prefix) < 0 ||
fclose(nat46))
return 4;
if (!(pid = fork())) {
fclose(fp);
fclose(stdin);
fclose(stdout);
fclose(stderr);
chdir("/");
setsid();
pause();
nat46 = fopen("/proc/net/nat46/control", "w");
if (nat46) {
fprintf(nat46, "del %s\n", argv[1]);
fclose(nat46);
}
} else {
fprintf(fp, "%d\n", pid);
}
return 0;
}
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