1 /*
2 * Copyright 2018 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 *
16 * main.c - main function
17 */
18
19 #include <arpa/inet.h>
20 #include <errno.h>
21 #include <netinet/in.h>
22 #include <stdint.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <sys/capability.h>
26 #include <unistd.h>
27
28 #include "clatd.h"
29 #include "common.h"
30 #include "config.h"
31 #include "logging.h"
32
33 #define DEVICEPREFIX "v4-"
34
35 /* function: stop_loop
36 * signal handler: stop the event loop
37 */
stop_loop()38 static void stop_loop() { running = 0; };
39
40 /* function: print_help
41 * in case the user is running this on the command line
42 */
print_help()43 void print_help() {
44 printf("android-clat arguments:\n");
45 printf("-i [uplink interface]\n");
46 printf("-p [plat prefix]\n");
47 printf("-4 [IPv4 address]\n");
48 printf("-6 [IPv6 address]\n");
49 printf("-t [tun file descriptor number]\n");
50 printf("-r [read socket descriptor number]\n");
51 printf("-w [write socket descriptor number]\n");
52 }
53
54 /* function: main
55 * allocate and setup the tun device, then run the event loop
56 */
main(int argc,char ** argv)57 int main(int argc, char **argv) {
58 struct tun_data tunnel;
59 int opt;
60 char *uplink_interface = NULL, *plat_prefix = NULL;
61 char *v4_addr = NULL, *v6_addr = NULL, *tunfd_str = NULL, *read_sock_str = NULL,
62 *write_sock_str = NULL;
63 unsigned len;
64
65 while ((opt = getopt(argc, argv, "i:p:4:6:t:r:w:h")) != -1) {
66 switch (opt) {
67 case 'i':
68 uplink_interface = optarg;
69 break;
70 case 'p':
71 plat_prefix = optarg;
72 break;
73 case '4':
74 v4_addr = optarg;
75 break;
76 case '6':
77 v6_addr = optarg;
78 break;
79 case 't':
80 tunfd_str = optarg;
81 break;
82 case 'r':
83 read_sock_str = optarg;
84 break;
85 case 'w':
86 write_sock_str = optarg;
87 break;
88 case 'h':
89 print_help();
90 exit(0);
91 default:
92 logmsg(ANDROID_LOG_FATAL, "Unknown option -%c. Exiting.", (char)optopt);
93 exit(1);
94 }
95 }
96
97 if (uplink_interface == NULL) {
98 logmsg(ANDROID_LOG_FATAL, "clatd called without an interface");
99 exit(1);
100 }
101
102 if (tunfd_str != NULL && !parse_int(tunfd_str, &tunnel.fd4)) {
103 logmsg(ANDROID_LOG_FATAL, "invalid tunfd %s", tunfd_str);
104 exit(1);
105 }
106 if (!tunnel.fd4) {
107 logmsg(ANDROID_LOG_FATAL, "no tunfd specified on commandline.");
108 exit(1);
109 }
110
111 if (read_sock_str != NULL && !parse_int(read_sock_str, &tunnel.read_fd6)) {
112 logmsg(ANDROID_LOG_FATAL, "invalid read socket %s", read_sock_str);
113 exit(1);
114 }
115 if (!tunnel.read_fd6) {
116 logmsg(ANDROID_LOG_FATAL, "no read_fd6 specified on commandline.");
117 exit(1);
118 }
119
120 if (write_sock_str != NULL && !parse_int(write_sock_str, &tunnel.write_fd6)) {
121 logmsg(ANDROID_LOG_FATAL, "invalid write socket %s", write_sock_str);
122 exit(1);
123 }
124 if (!tunnel.write_fd6) {
125 logmsg(ANDROID_LOG_FATAL, "no write_fd6 specified on commandline.");
126 exit(1);
127 }
128
129 len = snprintf(tunnel.device4, sizeof(tunnel.device4), "%s%s", DEVICEPREFIX, uplink_interface);
130 if (len >= sizeof(tunnel.device4)) {
131 logmsg(ANDROID_LOG_FATAL, "interface name too long '%s'", tunnel.device4);
132 exit(1);
133 }
134
135 Global_Clatd_Config.native_ipv6_interface = uplink_interface;
136 if (!plat_prefix || inet_pton(AF_INET6, plat_prefix, &Global_Clatd_Config.plat_subnet) <= 0) {
137 logmsg(ANDROID_LOG_FATAL, "invalid IPv6 address specified for plat prefix: %s", plat_prefix);
138 exit(1);
139 }
140
141 if (!v4_addr || !inet_pton(AF_INET, v4_addr, &Global_Clatd_Config.ipv4_local_subnet.s_addr)) {
142 logmsg(ANDROID_LOG_FATAL, "Invalid IPv4 address %s", v4_addr);
143 exit(1);
144 }
145
146 if (!v6_addr || !inet_pton(AF_INET6, v6_addr, &Global_Clatd_Config.ipv6_local_subnet)) {
147 logmsg(ANDROID_LOG_FATAL, "Invalid source address %s", v6_addr);
148 exit(1);
149 }
150
151 logmsg(ANDROID_LOG_INFO, "Starting clat version %s on %s plat=%s v4=%s v6=%s", CLATD_VERSION,
152 uplink_interface, plat_prefix ? plat_prefix : "(none)", v4_addr ? v4_addr : "(none)",
153 v6_addr ? v6_addr : "(none)");
154
155 // Loop until someone sends us a signal or brings down the tun interface.
156 if (signal(SIGTERM, stop_loop) == SIG_ERR) {
157 logmsg(ANDROID_LOG_FATAL, "sigterm handler failed: %s", strerror(errno));
158 exit(1);
159 }
160
161 event_loop(&tunnel);
162
163 logmsg(ANDROID_LOG_INFO, "Shutting down clat on %s", uplink_interface);
164
165 if (running) {
166 logmsg(ANDROID_LOG_INFO, "Clatd on %s waiting for SIGTERM", uplink_interface);
167 while (running) sleep(60);
168 logmsg(ANDROID_LOG_INFO, "Clatd on %s received SIGTERM", uplink_interface);
169 } else {
170 logmsg(ANDROID_LOG_INFO, "Clatd on %s already received SIGTERM", uplink_interface);
171 }
172 return 0;
173 }
174