149 lines
3.8 KiB
C
149 lines
3.8 KiB
C
/* 464xlatcfg.c
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*
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* Copyright (c) 2015 Steven Barth <cyrus@openwrt.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <netinet/icmp6.h>
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#include <netinet/in.h>
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#include <sys/socket.h>
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#include <arpa/inet.h>
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#include <net/if.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <signal.h>
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#include <stdio.h>
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#include <netdb.h>
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static void sighandler(__attribute__((unused)) int signal)
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{
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}
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int main(int argc, const char *argv[])
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{
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char buf[INET6_ADDRSTRLEN], prefix[INET6_ADDRSTRLEN + 4];
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int pid;
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if (argc <= 1) {
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fprintf(stderr, "Usage: %s <name> [ifname] [ipv6prefix] [ipv4addr] [ipv6addr]\n", argv[0]);
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return 1;
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}
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snprintf(buf, sizeof(buf), "/var/run/%s.pid", argv[1]);
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FILE *fp = fopen(buf, "r");
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if (fp) {
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fscanf(fp, "%d", &pid);
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kill(pid, SIGTERM);
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unlink(buf);
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fclose(fp);
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}
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if (!argv[2])
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return 0;
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if (!argv[3] || !argv[4] || !(fp = fopen(buf, "wx")))
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return 1;
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signal(SIGTERM, sighandler);
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prefix[sizeof(prefix) - 1] = 0;
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strncpy(prefix, argv[3], sizeof(prefix) - 1);
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if (!prefix[0]) {
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struct addrinfo hints = { .ai_family = AF_INET6 }, *res;
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if (getaddrinfo("ipv4only.arpa", NULL, &hints, &res) || !res) {
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sleep(3);
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if (getaddrinfo("ipv4only.arpa", NULL, &hints, &res) || !res)
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return 2;
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}
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struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)res->ai_addr;
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inet_ntop(AF_INET6, &sin6->sin6_addr, prefix, sizeof(prefix) - 4);
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strcat(prefix, "/96");
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freeaddrinfo(res);
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}
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int i = 0;
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int sock;
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struct sockaddr_in6 saddr;
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do {
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socklen_t saddrlen = sizeof(saddr);
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struct icmp6_filter filt;
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sock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
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ICMP6_FILTER_SETBLOCKALL(&filt);
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setsockopt(sock, IPPROTO_ICMPV6, ICMP6_FILTER, &filt, sizeof(filt));
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setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, argv[2], strlen(argv[2]));
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memset(&saddr, 0, sizeof(saddr));
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saddr.sin6_family = AF_INET6;
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saddr.sin6_addr.s6_addr32[0] = htonl(0x2001);
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saddr.sin6_addr.s6_addr32[1] = htonl(0xdb8);
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if (connect(sock, (struct sockaddr*)&saddr, sizeof(saddr)) ||
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getsockname(sock, (struct sockaddr*)&saddr, &saddrlen))
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return 3;
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if (!IN6_IS_ADDR_LINKLOCAL(&saddr.sin6_addr) || argv[5])
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break;
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close(sock);
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sleep(3);
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i++;
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} while (i < 3);
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struct ipv6_mreq mreq = {saddr.sin6_addr, if_nametoindex(argv[2])};
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if (!argv[5]) {
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if (IN6_IS_ADDR_LINKLOCAL(&mreq.ipv6mr_multiaddr))
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return 5;
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srandom(mreq.ipv6mr_multiaddr.s6_addr32[0] ^ mreq.ipv6mr_multiaddr.s6_addr32[1] ^
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mreq.ipv6mr_multiaddr.s6_addr32[2] ^ mreq.ipv6mr_multiaddr.s6_addr32[3]);
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mreq.ipv6mr_multiaddr.s6_addr32[2] = random();
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mreq.ipv6mr_multiaddr.s6_addr32[3] = random();
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} else if (inet_pton(AF_INET6, argv[5], &mreq.ipv6mr_multiaddr) != 1) {
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return 1;
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}
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if (setsockopt(sock, SOL_IPV6, IPV6_JOIN_ANYCAST, &mreq, sizeof(mreq)))
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return 3;
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inet_ntop(AF_INET6, &mreq.ipv6mr_multiaddr, buf, sizeof(buf));
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fputs(buf, stdout);
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fputc('\n', stdout);
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fflush(stdout);
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FILE *nat46 = fopen("/proc/net/nat46/control", "w");
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if (!nat46 || fprintf(nat46, "add %s\nconfig %s local.style NONE local.v4 %s/32 local.v6 %s/128 "
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"remote.style RFC6052 remote.v6 %s\n", argv[1], argv[1], argv[4], buf, prefix) < 0 ||
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fclose(nat46))
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return 4;
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if (!(pid = fork())) {
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fclose(fp);
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fclose(stdin);
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fclose(stdout);
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fclose(stderr);
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chdir("/");
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setsid();
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pause();
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nat46 = fopen("/proc/net/nat46/control", "w");
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if (nat46) {
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fprintf(nat46, "del %s\n", argv[1]);
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fclose(nat46);
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}
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} else {
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fprintf(fp, "%d\n", pid);
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}
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return 0;
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}
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