OpenWrt – Blame information for rev 2

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1 office 1 /* 464xlatcfg.c
2 *
3 * Copyright (c) 2015 Steven Barth <cyrus@openwrt.org>
4 * Copyright (c) 2017 Hans Dedecker <dedeckeh@gmail.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2
8 * as published by the Free Software Foundation
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 */
15  
16 #include <netinet/icmp6.h>
17 #include <netinet/in.h>
18 #include <sys/socket.h>
19 #include <arpa/inet.h>
20 #include <net/if.h>
21 #include <unistd.h>
22 #include <stdlib.h>
23 #include <signal.h>
24 #include <stdio.h>
25 #include <netdb.h>
26  
27 static void sighandler(__attribute__((unused)) int signal)
28 {
29 }
30  
31 int main(int argc, const char *argv[])
32 {
33 char buf[INET6_ADDRSTRLEN], prefix[INET6_ADDRSTRLEN + 4];
34 int pid;
35  
36 if (argc <= 1) {
37 fprintf(stderr, "Usage: %s <name> [ifname] [ipv6prefix] [ipv4addr] [ipv6addr]\n", argv[0]);
38 return 1;
39 }
40  
41 snprintf(buf, sizeof(buf), "/var/run/%s.pid", argv[1]);
42 FILE *fp = fopen(buf, "r");
43 if (fp) {
44 if (fscanf(fp, "%d", &pid) == 1)
45 kill(pid, SIGTERM);
46  
47 unlink(buf);
48 fclose(fp);
49 }
50  
51 if (!argv[2])
52 return 0;
53  
54 if (!argv[3] || !argv[4] || !(fp = fopen(buf, "wx")))
55 return 1;
56  
57 signal(SIGTERM, SIG_DFL);
58 setvbuf(fp, NULL, _IOLBF, 0);
59 fprintf(fp, "%d\n", getpid());
60  
61 prefix[sizeof(prefix) - 1] = 0;
62 strncpy(prefix, argv[3], sizeof(prefix) - 1);
63  
64 if (!prefix[0]) {
65 struct addrinfo hints = { .ai_family = AF_INET6 }, *res;
66 if (getaddrinfo("ipv4only.arpa", NULL, &hints, &res) || !res) {
67 sleep(3);
68 if (getaddrinfo("ipv4only.arpa", NULL, &hints, &res) || !res)
69 return 2;
70 }
71  
72 struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)res->ai_addr;
73 inet_ntop(AF_INET6, &sin6->sin6_addr, prefix, sizeof(prefix) - 4);
74 strcat(prefix, "/96");
75 freeaddrinfo(res);
76 }
77  
78 int i = 0;
79 int sock;
80 struct sockaddr_in6 saddr;
81  
82 do {
83 socklen_t saddrlen = sizeof(saddr);
84 struct icmp6_filter filt;
85  
86 sock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
87 ICMP6_FILTER_SETBLOCKALL(&filt);
88 setsockopt(sock, IPPROTO_ICMPV6, ICMP6_FILTER, &filt, sizeof(filt));
89 setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, argv[2], strlen(argv[2]));
90 memset(&saddr, 0, sizeof(saddr));
91 saddr.sin6_family = AF_INET6;
92 saddr.sin6_addr.s6_addr32[0] = htonl(0x2001);
93 saddr.sin6_addr.s6_addr32[1] = htonl(0xdb8);
94 if (connect(sock, (struct sockaddr*)&saddr, sizeof(saddr)) ||
95 getsockname(sock, (struct sockaddr*)&saddr, &saddrlen))
96 return 3;
97  
98 if (!IN6_IS_ADDR_LINKLOCAL(&saddr.sin6_addr) || argv[5])
99 break;
100  
101 close(sock);
102 sleep(3);
103 i++;
104 } while (i < 3);
105  
106 struct ipv6_mreq mreq = {saddr.sin6_addr, if_nametoindex(argv[2])};
107 if (!argv[5]) {
108 if (IN6_IS_ADDR_LINKLOCAL(&mreq.ipv6mr_multiaddr))
109 return 5;
110  
111 srandom(mreq.ipv6mr_multiaddr.s6_addr32[0] ^ mreq.ipv6mr_multiaddr.s6_addr32[1] ^
112 mreq.ipv6mr_multiaddr.s6_addr32[2] ^ mreq.ipv6mr_multiaddr.s6_addr32[3]);
113 mreq.ipv6mr_multiaddr.s6_addr32[2] = random();
114 mreq.ipv6mr_multiaddr.s6_addr32[3] = random();
115 } else if (inet_pton(AF_INET6, argv[5], &mreq.ipv6mr_multiaddr) != 1) {
116 return 1;
117 }
118  
119 if (setsockopt(sock, SOL_IPV6, IPV6_JOIN_ANYCAST, &mreq, sizeof(mreq)))
120 return 3;
121  
122 inet_ntop(AF_INET6, &mreq.ipv6mr_multiaddr, buf, sizeof(buf));
123 fputs(buf, stdout);
124 fputc('\n', stdout);
125 fflush(stdout);
126  
127 FILE *nat46 = fopen("/proc/net/nat46/control", "w");
128 if (!nat46 || fprintf(nat46, "add %s\nconfig %s local.style NONE local.v4 %s/32 local.v6 %s/128 "
129 "remote.style RFC6052 remote.v6 %s\n", argv[1], argv[1], argv[4], buf, prefix) < 0 ||
130 fclose(nat46))
131 return 4;
132  
133 if (!(pid = fork())) {
134 fclose(fp);
135 fclose(stdin);
136 fclose(stdout);
137 fclose(stderr);
138 chdir("/");
139 setsid();
140 signal(SIGTERM, sighandler);
141 pause();
142  
143 nat46 = fopen("/proc/net/nat46/control", "w");
144 if (nat46) {
145 fprintf(nat46, "del %s\n", argv[1]);
146 fclose(nat46);
147 }
148 } else {
149 rewind(fp);
150 fprintf(fp, "%d\n", pid);
151 }
152  
153 return 0;
154 }