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