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