www.tinc-vpn.org Git - tinc/blob - src/multicast_device.c

   1 /*
   2     device.c -- multicast socket
   3     Copyright (C) 2002-2005 Ivo Timmermans,
   4                   2002-2014 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
  58         if(!space) {
  59                 logger(LOG_ERR, "Port number required for %s", device_info);
  60                 free(host);
  61                 return false;
  62         }
  63
  64         *space++ = 0;
  65         port = space;
  66         space = strchr(port, ' ');
  67
  68         if(space) {
  69                 *space++ = 0;
  70                 ttl = atoi(space);
  71         }
  72
  73         ai = str2addrinfo(host, port, SOCK_DGRAM);
  74
  75         if(!ai) {
  76                 free(host);
  77                 return false;
  78         }
  79
  80         device_fd = socket(ai->ai_family, SOCK_DGRAM, IPPROTO_UDP);
  81
  82         if(device_fd < 0) {
  83                 logger(LOG_ERR, "Creating socket failed: %s", sockstrerror(sockerrno));
  84                 free(host);
  85                 return false;
  86         }
  87
  88 #ifdef FD_CLOEXEC
  89         fcntl(device_fd, F_SETFD, FD_CLOEXEC);
  90 #endif
  91
  92         static const int one = 1;
  93         setsockopt(device_fd, SOL_SOCKET, SO_REUSEADDR, (void *)&one, sizeof(one));
  94
  95         if(bind(device_fd, ai->ai_addr, ai->ai_addrlen)) {
  96                 closesocket(device_fd);
  97                 logger(LOG_ERR, "Can't bind to %s %s: %s", host, port, sockstrerror(sockerrno));
  98                 free(host);
  99                 return false;
 100         }
 101
 102         switch(ai->ai_family) {
 103 #ifdef IP_ADD_MEMBERSHIP
 104
 105         case AF_INET: {
 106                 struct ip_mreq mreq;
 107                 struct sockaddr_in in;
 108                 memcpy(&in, ai->ai_addr, sizeof(in));
 109                 mreq.imr_multiaddr.s_addr = in.sin_addr.s_addr;
 110                 mreq.imr_interface.s_addr = htonl(INADDR_ANY);
 111
 112                 if(setsockopt(device_fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (void *)&mreq, sizeof(mreq))) {
 113                         logger(LOG_ERR, "Cannot join multicast group %s %s: %s", host, port, sockstrerror(sockerrno));
 114                         closesocket(device_fd);
 115                         free(host);
 116                         return false;
 117                 }
 118
 119 #ifdef IP_MULTICAST_LOOP
 120                 setsockopt(device_fd, IPPROTO_IP, IP_MULTICAST_LOOP, (const void *)&one, sizeof(one));
 121 #endif
 122 #ifdef IP_MULTICAST_TTL
 123                 setsockopt(device_fd, IPPROTO_IP, IP_MULTICAST_TTL, (void *)&ttl, sizeof(ttl));
 124 #endif
 125         }
 126         break;
 127 #endif
 128
 129 #ifdef IPV6_JOIN_GROUP
 130
 131         case AF_INET6: {
 132                 struct ipv6_mreq mreq;
 133                 struct sockaddr_in6 in6;
 134                 memcpy(&in6, ai->ai_addr, sizeof(in6));
 135                 memcpy(&mreq.ipv6mr_multiaddr, &in6.sin6_addr, sizeof(mreq.ipv6mr_multiaddr));
 136                 mreq.ipv6mr_interface = in6.sin6_scope_id;
 137
 138                 if(setsockopt(device_fd, IPPROTO_IPV6, IPV6_JOIN_GROUP, (void *)&mreq, sizeof(mreq))) {
 139                         logger(LOG_ERR, "Cannot join multicast group %s %s: %s", host, port, sockstrerror(sockerrno));
 140                         closesocket(device_fd);
 141                         free(host);
 142                         return false;
 143                 }
 144
 145 #ifdef IPV6_MULTICAST_LOOP
 146                 setsockopt(device_fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, (const void *)&one, sizeof(one));
 147 #endif
 148 #ifdef IPV6_MULTICAST_HOPS
 149                 setsockopt(device_fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, (void *)&ttl, sizeof(ttl));
 150 #endif
 151         }
 152         break;
 153 #endif
 154
 155         default:
 156                 logger(LOG_ERR, "Multicast for address family %x unsupported", ai->ai_family);
 157                 closesocket(device_fd);
 158                 free(host);
 159                 return false;
 160         }
 161
 162         free(host);
 163         logger(LOG_INFO, "%s is a %s", device, device_info);
 164
 165         return true;
 166 }
 167
 168 static void close_device(void) {
 169         close(device_fd);
 170
 171         free(device);
 172         free(iface);
 173
 174         if(ai) {
 175                 freeaddrinfo(ai);
 176         }
 177 }
 178
 179 static bool read_packet(vpn_packet_t *packet) {
 180         int lenin;
 181
 182         if((lenin = recv(device_fd, (void *)packet->data, MTU, 0)) <= 0) {
 183                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 184                        device, strerror(errno));
 185                 return false;
 186         }
 187
 188         if(!memcmp(&ignore_src, packet->data + 6, sizeof(ignore_src))) {
 189                 ifdebug(SCARY_THINGS) logger(LOG_DEBUG, "Ignoring loopback packet of %d bytes from %s", lenin, device_info);
 190                 packet->len = 0;
 191                 return true;
 192         }
 193
 194         packet->len = lenin;
 195
 196         device_total_in += packet->len;
 197
 198         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 199                                 device_info);
 200
 201         return true;
 202 }
 203
 204 static bool write_packet(vpn_packet_t *packet) {
 205         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 206                                 packet->len, device_info);
 207
 208         if(sendto(device_fd, (void *)packet->data, packet->len, 0, ai->ai_addr, ai->ai_addrlen) < 0) {
 209                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 210                        strerror(errno));
 211                 return false;
 212         }
 213
 214         device_total_out += packet->len;
 215
 216         memcpy(&ignore_src, packet->data + 6, sizeof(ignore_src));
 217
 218         return true;
 219 }
 220
 221 static void dump_device_stats(void) {
 222         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 223         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
 224         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
 225 }
 226
 227 const devops_t multicast_devops = {
 228         .setup = setup_device,
 229         .close = close_device,
 230         .read = read_packet,
 231         .write = write_packet,
 232         .dump_stats = dump_device_stats,
 233 };
 234
 235 #if 0
 236
 237 static bool not_supported(void) {
 238         logger(LOG_ERR, "Raw socket device not supported on this platform");
 239         return false;
 240 }
 241
 242 const devops_t multicast_devops = {
 243         .setup = not_supported,
 244         .close = NULL,
 245         .read = NULL,
 246         .write = NULL,
 247         .dump_stats = NULL,
 248 };
 249 #endif