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