release/src/router/tinc/src/multicast_device.c

   1 /*
   2     device.c -- multicast socket
   3     Copyright (C) 2002-2005 Ivo Timmermans,
   4                   2002-2013 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 struct addrinfo *ai = NULL;
  35 static mac_t ignore_src = {{0}};
  36
  37 static bool setup_device(void) {
  38         char *host = NULL;
  39         char *port;
  40         char *space;
  41         int ttl = 1;
  42
  43         device_info = "multicast socket";
  44
  45         get_config_string(lookup_config(config_tree, "Interface"), &iface);
  46
  47         if(!get_config_string(lookup_config(config_tree, "Device"), &device)) {
  48                 logger(DEBUG_ALWAYS, LOG_ERR, "Device variable required for %s", device_info);
  49                 goto error;
  50         }
  51
  52         host = xstrdup(device);
  53         space = strchr(host, ' ');
  54         if(!space) {
  55                 logger(DEBUG_ALWAYS, LOG_ERR, "Port number required for %s", device_info);
  56                 goto error;
  57         }
  58
  59         *space++ = 0;
  60         port = space;
  61         space = strchr(port, ' ');
  62
  63         if(space) {
  64                 *space++ = 0;
  65                 ttl = atoi(space);
  66         }
  67
  68         ai = str2addrinfo(host, port, SOCK_DGRAM);
  69         if(!ai)
  70                 goto error;
  71
  72         device_fd = socket(ai->ai_family, SOCK_DGRAM, IPPROTO_UDP);
  73         if(device_fd < 0) {
  74                 logger(DEBUG_ALWAYS, LOG_ERR, "Creating socket failed: %s", sockstrerror(sockerrno));
  75                 goto error;
  76         }
  77
  78 #ifdef FD_CLOEXEC
  79         fcntl(device_fd, F_SETFD, FD_CLOEXEC);
  80 #endif
  81
  82         static const int one = 1;
  83         setsockopt(device_fd, SOL_SOCKET, SO_REUSEADDR, (void *)&one, sizeof one);
  84
  85         if(bind(device_fd, ai->ai_addr, ai->ai_addrlen)) {
  86                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to %s %s: %s", host, port, sockstrerror(sockerrno));
  87                 goto error;
  88         }
  89
  90         switch(ai->ai_family) {
  91 #ifdef IP_ADD_MEMBERSHIP
  92                 case AF_INET: {
  93                         struct ip_mreq mreq;
  94                         struct sockaddr_in in;
  95                         memcpy(&in, ai->ai_addr, sizeof in);
  96                         mreq.imr_multiaddr.s_addr = in.sin_addr.s_addr;
  97                         mreq.imr_interface.s_addr = htonl(INADDR_ANY);
  98                         if(setsockopt(device_fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (void *)&mreq, sizeof mreq)) {
  99                                 logger(DEBUG_ALWAYS, LOG_ERR, "Cannot join multicast group %s %s: %s", host, port, sockstrerror(sockerrno));
 100                                 goto error;
 101                         }
 102 #ifdef IP_MULTICAST_LOOP
 103                         setsockopt(device_fd, IPPROTO_IP, IP_MULTICAST_LOOP, (const void *)&one, sizeof one);
 104 #endif
 105 #ifdef IP_MULTICAST_TTL
 106                         setsockopt(device_fd, IPPROTO_IP, IP_MULTICAST_TTL, (void *)&ttl, sizeof ttl);
 107 #endif
 108                 } break;
 109 #endif
 110
 111 #ifdef IPV6_JOIN_GROUP
 112                 case AF_INET6: {
 113                         struct ipv6_mreq mreq;
 114                         struct sockaddr_in6 in6;
 115                         memcpy(&in6, ai->ai_addr, sizeof in6);
 116                         memcpy(&mreq.ipv6mr_multiaddr, &in6.sin6_addr, sizeof mreq.ipv6mr_multiaddr);
 117                         mreq.ipv6mr_interface = in6.sin6_scope_id;
 118                         if(setsockopt(device_fd, IPPROTO_IPV6, IPV6_JOIN_GROUP, (void *)&mreq, sizeof mreq)) {
 119                                 logger(DEBUG_ALWAYS, LOG_ERR, "Cannot join multicast group %s %s: %s", host, port, sockstrerror(sockerrno));
 120                                 goto error;
 121                         }
 122 #ifdef IPV6_MULTICAST_LOOP
 123                         setsockopt(device_fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, (const void *)&one, sizeof one);
 124 #endif
 125 #ifdef IPV6_MULTICAST_HOPS
 126                         setsockopt(device_fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, (void *)&ttl, sizeof ttl);
 127 #endif
 128                 } break;
 129 #endif
 130
 131                 default:
 132                         logger(DEBUG_ALWAYS, LOG_ERR, "Multicast for address family %hx unsupported", ai->ai_family);
 133                         goto error;
 134         }
 135
 136         logger(DEBUG_ALWAYS, LOG_INFO, "%s is a %s", device, device_info);
 137
 138         return true;
 139
 140 error:
 141         if(device_fd >= 0)
 142                 closesocket(device_fd);
 143         if(ai)
 144                 freeaddrinfo(ai);
 145         free(host);
 146
 147         return false;
 148 }
 149
 150 static void close_device(void) {
 151         close(device_fd);
 152
 153         free(device);
 154         free(iface);
 155
 156         if(ai)
 157                 freeaddrinfo(ai);
 158 }
 159
 160 static bool read_packet(vpn_packet_t *packet) {
 161         int lenin;
 162
 163         if((lenin = recv(device_fd, (void *)packet->data, MTU, 0)) <= 0) {
 164                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
 165                            device, strerror(errno));
 166                 return false;
 167         }
 168
 169         if(!memcmp(&ignore_src, packet->data + 6, sizeof ignore_src)) {
 170                 logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Ignoring loopback packet of %d bytes from %s", lenin, device_info);
 171                 return false;
 172         }
 173
 174         packet->len = lenin;
 175
 176         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 177                            device_info);
 178
 179         return true;
 180 }
 181
 182 static bool write_packet(vpn_packet_t *packet) {
 183         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Writing packet of %d bytes to %s",
 184                            packet->len, device_info);
 185
 186         if(sendto(device_fd, (void *)packet->data, packet->len, 0, ai->ai_addr, ai->ai_addrlen) < 0) {
 187                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't write to %s %s: %s", device_info, device,
 188                            strerror(errno));
 189                 return false;
 190         }
 191
 192         memcpy(&ignore_src, packet->data + 6, sizeof ignore_src);
 193
 194         return true;
 195 }
 196
 197 const devops_t multicast_devops = {
 198         .setup = setup_device,
 199         .close = close_device,
 200         .read = read_packet,
 201         .write = write_packet,
 202 };