08d44d4173ffe4b18ed5997f95fe05b8056f1ff7
[oweals/tinc.git] / src / multicast_device.c
1 /*
2     device.c -- multicast socket
3     Copyright (C) 2002-2005 Ivo Timmermans,
4                   2002-2012 Guus Sliepen <guus@tinc-vpn.org>
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 as published by
8     the Free Software Foundation; either version 2 of the License, or
9     (at your option) any later version.
10
11     This program is distributed in the hope that it will be useful,
12     but WITHOUT ANY WARRANTY; without even the implied warranty of
13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14     GNU General Public License for more details.
15
16     You should have received a copy of the GNU General Public License along
17     with this program; if not, write to the Free Software Foundation, Inc.,
18     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
19 */
20
21 #include "system.h"
22
23 #include "conf.h"
24 #include "device.h"
25 #include "net.h"
26 #include "logger.h"
27 #include "netutl.h"
28 #include "utils.h"
29 #include "route.h"
30 #include "xalloc.h"
31
32 static char *device_info;
33
34 static uint64_t device_total_in = 0;
35 static uint64_t device_total_out = 0;
36
37 static struct addrinfo *ai = NULL;
38 static mac_t ignore_src = {0};
39
40 static bool setup_device(void) {
41         char *host;
42         char *port;
43         char *space;
44         int ttl = 1;
45
46         device_info = "multicast socket";
47
48         get_config_string(lookup_config(config_tree, "Interface"), &iface);
49
50         if(!get_config_string(lookup_config(config_tree, "Device"), &device)) {
51                 logger(LOG_ERR, "Device variable required for %s", device_info);
52                 return false;
53         }
54
55         host = xstrdup(device);
56         space = strchr(host, ' ');
57         if(!space) {
58                 logger(LOG_ERR, "Port number required for %s", device_info);
59                 return false;
60         }
61
62         *space++ = 0;
63         port = space;
64         space = strchr(port, ' ');
65
66         if(space) {
67                 *space++ = 0;
68                 ttl = atoi(space);
69         }
70
71         ai = str2addrinfo(host, port, SOCK_DGRAM);
72         if(!ai)
73                 return false;
74
75         device_fd = socket(ai->ai_family, SOCK_DGRAM, IPPROTO_UDP);
76         if(device_fd < 0) {
77                 logger(LOG_ERR, "Creating socket failed: %s", sockstrerror(sockerrno));
78                 return false;
79         }
80
81 #ifdef FD_CLOEXEC
82         fcntl(device_fd, F_SETFD, FD_CLOEXEC);
83 #endif
84
85         static const int one = 1;
86         setsockopt(device_fd, SOL_SOCKET, SO_REUSEADDR, (void *)&one, sizeof one);
87
88         if(bind(device_fd, ai->ai_addr, ai->ai_addrlen)) {
89                 closesocket(device_fd);
90                 logger(LOG_ERR, "Can't bind to %s %s: %s", host, port, sockstrerror(sockerrno));
91                 return false;
92         }
93
94         switch(ai->ai_family) {
95 #ifdef IP_ADD_MEMBERSHIP
96                 case AF_INET: {
97                         struct ip_mreq mreq;
98                         struct sockaddr_in in;
99                         memcpy(&in, ai->ai_addr, sizeof in);
100                         mreq.imr_multiaddr.s_addr = in.sin_addr.s_addr;
101                         mreq.imr_interface.s_addr = htonl(INADDR_ANY);
102                         if(setsockopt(device_fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (void *)&mreq, sizeof mreq)) {
103                                 logger(LOG_ERR, "Cannot join multicast group %s %s: %s", host, port, sockstrerror(sockerrno));
104                                 closesocket(device_fd);
105                                 return false;
106                         }
107 #ifdef IP_MULTICAST_LOOP
108                         setsockopt(device_fd, IPPROTO_IP, IP_MULTICAST_LOOP, (const void *)&one, sizeof one);
109 #endif
110 #ifdef IP_MULTICAST_TTL
111                         setsockopt(device_fd, IPPROTO_IP, IP_MULTICAST_TTL, (void *)&ttl, sizeof ttl);
112 #endif
113                 } break;
114 #endif
115
116 #ifdef IPV6_JOIN_GROUP
117                 case AF_INET6: {
118                         struct ipv6_mreq mreq;
119                         struct sockaddr_in6 in6;
120                         memcpy(&in6, ai->ai_addr, sizeof in6);
121                         memcpy(&mreq.ipv6mr_multiaddr, &in6.sin6_addr, sizeof mreq.ipv6mr_multiaddr);
122                         mreq.ipv6mr_interface = in6.sin6_scope_id;
123                         if(setsockopt(device_fd, IPPROTO_IPV6, IPV6_JOIN_GROUP, (void *)&mreq, sizeof mreq)) {
124                                 logger(LOG_ERR, "Cannot join multicast group %s %s: %s", host, port, sockstrerror(sockerrno));
125                                 closesocket(device_fd);
126                                 return false;
127                         }
128 #ifdef IPV6_MULTICAST_LOOP
129                         setsockopt(device_fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, (const void *)&one, sizeof one);
130 #endif
131 #ifdef IPV6_MULTICAST_HOPS
132                         setsockopt(device_fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, (void *)&ttl, sizeof ttl);
133 #endif
134                 } break;
135 #endif
136         
137                 default:
138                         logger(LOG_ERR, "Multicast for address family %hx unsupported", ai->ai_family);
139                         closesocket(device_fd);
140                         return false;
141         }
142
143         logger(LOG_INFO, "%s is a %s", device, device_info);
144
145         return true;
146 }
147
148 static void close_device(void) {
149         close(device_fd);
150
151         free(device);
152         free(iface);
153
154         if(ai)
155                 freeaddrinfo(ai);
156 }
157
158 static bool read_packet(vpn_packet_t *packet) {
159         int lenin;
160
161         if((lenin = recv(device_fd, packet->data, MTU, 0)) <= 0) {
162                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
163                            device, strerror(errno));
164                 return false;
165         }
166
167         if(!memcmp(&ignore_src, packet->data + 6, sizeof ignore_src)) {
168                 ifdebug(SCARY_THINGS) logger(LOG_DEBUG, "Ignoring loopback packet of %d bytes from %s", lenin, device_info);
169                 packet->len = 0;
170                 return true;
171         }
172
173         packet->len = lenin;
174
175         device_total_in += packet->len;
176
177         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
178                            device_info);
179
180         return true;
181 }
182
183 static bool write_packet(vpn_packet_t *packet) {
184         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
185                            packet->len, device_info);
186
187         if(sendto(device_fd, packet->data, packet->len, 0, ai->ai_addr, ai->ai_addrlen) < 0) {
188                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
189                            strerror(errno));
190                 return false;
191         }
192
193         device_total_out += packet->len;
194
195         memcpy(&ignore_src, packet->data + 6, sizeof ignore_src);
196
197         return true;
198 }
199
200 static void dump_device_stats(void) {
201         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
202         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
203         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
204 }
205
206 const devops_t multicast_devops = {
207         .setup = setup_device,
208         .close = close_device,
209         .read = read_packet,
210         .write = write_packet,
211         .dump_stats = dump_device_stats,
212 };
213
214 #if 0
215
216 static bool not_supported(void) {
217         logger(LOG_ERR, "Raw socket device not supported on this platform");
218         return false;
219 }
220
221 const devops_t multicast_devops = {
222         .setup = not_supported,
223         .close = NULL,
224         .read = NULL,
225         .write = NULL,
226         .dump_stats = NULL,
227 };
228 #endif