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

   1 /*
   2     route.c -- routing
   3     Copyright (C) 2000-2003 Ivo Timmermans <ivo@o2w.nl>,
   4                   2000-2003 Guus Sliepen <guus@sliepen.eu.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
  17     along with this program; if not, write to the Free Software
  18     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19
  20     $Id: route.c,v 1.1.2.70 2003/12/12 19:52:25 guus Exp $
  21 */
  22
  23 #include "system.h"
  24
  25 #ifdef HAVE_NET_ETHERNET_H
  26 #include <net/ethernet.h>
  27 #endif
  28 #ifdef HAVE_NET_IF_ARP_H
  29 #include <net/if_arp.h>
  30 #endif
  31 #ifdef HAVE_NETINET_IP_ICMP_H
  32 #include <netinet/ip_icmp.h>
  33 #endif
  34 #ifdef HAVE_NETINET_ICMP6_H
  35 #include <netinet/icmp6.h>
  36 #endif
  37 #ifdef HAVE_NETINET_IF_ETHER_H
  38 #include <netinet/if_ether.h>
  39 #endif
  40
  41 #include "avl_tree.h"
  42 #include "connection.h"
  43 #include "ethernet.h"
  44 #include "ipv4.h"
  45 #include "ipv6.h"
  46 #include "logger.h"
  47 #include "net.h"
  48 #include "protocol.h"
  49 #include "route.h"
  50 #include "subnet.h"
  51 #include "utils.h"
  52
  53 rmode_t routing_mode = RMODE_ROUTER;
  54 bool priorityinheritance = false;
  55 int macexpire = 600;
  56 int multicastexpire = 375;
  57 bool overwrite_mac = false;
  58 mac_t mymac = {{0xFE, 0xFD, 0, 0, 0, 0}};
  59
  60 /* Sizes of various headers */
  61
  62 static const size_t ether_size = sizeof(struct ether_header);
  63 static const size_t arp_size = sizeof(struct ether_arp);
  64 static const size_t ip_size = sizeof(struct ip);
  65 static const size_t icmp_size = sizeof(struct icmp) - sizeof(struct ip);
  66 static const size_t ip6_size = sizeof(struct ip6_hdr);
  67 static const size_t icmp6_size = sizeof(struct icmp6_hdr);
  68 static const size_t ns_size = sizeof(struct nd_neighbor_solicit);
  69 static const size_t opt_size = sizeof(struct nd_opt_hdr);
  70
  71 /* RFC 1071 */
  72
  73 static uint16_t inet_checksum(void *data, int len, uint16_t prevsum)
  74 {
  75         uint16_t *p = data;
  76         uint32_t checksum = prevsum ^ 0xFFFF;
  77
  78         while(len >= 2) {
  79                 checksum += *p++;
  80                 len -= 2;
  81         }
  82
  83         if(len)
  84                 checksum += *(uint8_t *)p;
  85
  86         while(checksum >> 16)
  87                 checksum = (checksum & 0xFFFF) + (checksum >> 16);
  88
  89         return ~checksum;
  90 }
  91
  92 static bool ratelimit(int frequency) {
  93         static time_t lasttime = 0;
  94         static int count = 0;
  95
  96         if(lasttime == now) {
  97                 if(++count > frequency)
  98                         return true;
  99         } else {
 100                 lasttime = now;
 101                 count = 0;
 102         }
 103
 104         return false;
 105 }
 106
 107 static bool checklength(node_t *source, vpn_packet_t *packet, length_t length) {
 108         if(packet->len < length) {
 109                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Got too short packet from %s (%s)"), source->name, source->hostname);
 110                 return false;
 111         } else
 112                 return true;
 113 }
 114
 115 static void learn_mac(mac_t *address)
 116 {
 117         subnet_t *subnet;
 118         avl_node_t *node;
 119         connection_t *c;
 120
 121         cp();
 122
 123         subnet = lookup_subnet_mac(address);
 124
 125         /* If we don't know this MAC address yet, store it */
 126
 127         if(!subnet) {
 128                 ifdebug(TRAFFIC) logger(LOG_INFO, _("Learned new MAC address %hx:%hx:%hx:%hx:%hx:%hx"),
 129                                    address->x[0], address->x[1], address->x[2], address->x[3],
 130                                    address->x[4], address->x[5]);
 131
 132                 subnet = new_subnet();
 133                 subnet->type = SUBNET_MAC;
 134                 subnet->expires = now + macexpire;
 135                 subnet->net.mac.address = *address;
 136                 subnet_add(myself, subnet);
 137
 138                 /* And tell all other tinc daemons it's our MAC */
 139
 140                 for(node = connection_tree->head; node; node = node->next) {
 141                         c = node->data;
 142                         if(c->status.active)
 143                                 send_add_subnet(c, subnet);
 144                 }
 145         }
 146
 147         if(subnet->expires)
 148                 subnet->expires = now + macexpire;
 149 }
 150
 151 void age_subnets(void)
 152 {
 153         subnet_t *s;
 154         connection_t *c;
 155         avl_node_t *node, *next, *node2;
 156
 157         cp();
 158
 159         for(node = myself->subnet_tree->head; node; node = next) {
 160                 next = node->next;
 161                 s = node->data;
 162                 if(s->expires && s->expires < now) {
 163                         ifdebug(TRAFFIC) {
 164                                 char netstr[MAXNETSTR];
 165                                 if(net2str(netstr, sizeof netstr, s))
 166                                         logger(LOG_INFO, _("Subnet %s expired"), netstr);
 167                         }
 168
 169                         for(node2 = connection_tree->head; node2; node2 = node2->next) {
 170                                 c = node2->data;
 171                                 if(c->status.active)
 172                                         send_del_subnet(c, s);
 173                         }
 174
 175                         subnet_del(myself, s);
 176                 }
 177         }
 178 }
 179
 180 static void route_mac(node_t *source, vpn_packet_t *packet)
 181 {
 182         subnet_t *subnet;
 183
 184         cp();
 185
 186         /* Learn source address */
 187
 188         if(source == myself)
 189                 learn_mac((mac_t *)(&packet->data[6]));
 190
 191         /* Lookup destination address */
 192
 193         subnet = lookup_subnet_mac((mac_t *)(&packet->data[0]));
 194
 195         if(!subnet) {
 196                 broadcast_packet(source, packet);
 197                 return;
 198         }
 199
 200         if(subnet->owner == source) {
 201                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Packet looping back to %s (%s)!"), source->name, source->hostname);
 202                 return;
 203         }
 204
 205         send_packet(subnet->owner, packet);
 206 }
 207
 208 /* RFC 792 */
 209
 210 static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, uint8_t code)
 211 {
 212         struct ip ip = {0};
 213         struct icmp icmp = {0};
 214
 215         struct in_addr ip_src;
 216         struct in_addr ip_dst;
 217         uint32_t oldlen;
 218
 219         if(ratelimit(3))
 220                 return;
 221
 222         cp();
 223
 224         /* Copy headers from packet into properly aligned structs on the stack */
 225
 226         memcpy(&ip, packet->data + ether_size, ip_size);
 227
 228         /* Remember original source and destination */
 229
 230         ip_src = ip.ip_src;
 231         ip_dst = ip.ip_dst;
 232
 233         oldlen = packet->len - ether_size;
 234
 235         if(oldlen >= IP_MSS - ip_size - icmp_size)
 236                 oldlen = IP_MSS - ip_size - icmp_size;
 237
 238         /* Copy first part of original contents to ICMP message */
 239
 240         memmove(packet->data + ether_size + ip_size + icmp_size, packet->data + ether_size, oldlen);
 241
 242         /* Fill in IPv4 header */
 243
 244         ip.ip_v = 4;
 245         ip.ip_hl = ip_size / 4;
 246         ip.ip_tos = 0;
 247         ip.ip_len = htons(ip_size + icmp_size + oldlen);
 248         ip.ip_id = 0;
 249         ip.ip_off = 0;
 250         ip.ip_ttl = 255;
 251         ip.ip_p = IPPROTO_ICMP;
 252         ip.ip_sum = 0;
 253         ip.ip_src = ip_dst;
 254         ip.ip_dst = ip_src;
 255
 256         ip.ip_sum = inet_checksum(&ip, ip_size, ~0);
 257
 258         /* Fill in ICMP header */
 259
 260         icmp.icmp_type = ICMP_DEST_UNREACH;
 261         icmp.icmp_code = code;
 262         icmp.icmp_cksum = 0;
 263
 264         icmp.icmp_cksum = inet_checksum(&icmp, icmp_size, ~0);
 265         icmp.icmp_cksum = inet_checksum(packet->data + ether_size + ip_size + icmp_size, oldlen, icmp.icmp_cksum);
 266
 267         /* Copy structs on stack back to packet */
 268
 269         memcpy(packet->data + ether_size, &ip, ip_size);
 270         memcpy(packet->data + ether_size + ip_size, &icmp, icmp_size);
 271
 272         packet->len = ether_size + ip_size + icmp_size + oldlen;
 273
 274         send_packet(source, packet);
 275 }
 276
 277 static void route_ipv4_unicast(node_t *source, vpn_packet_t *packet)
 278 {
 279         subnet_t *subnet;
 280
 281         cp();
 282
 283         subnet = lookup_subnet_ipv4((ipv4_t *) &packet->data[30]);
 284
 285         if(!subnet) {
 286                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet from %s (%s): unknown IPv4 destination address %d.%d.%d.%d"),
 287                                 source->name, source->hostname,
 288                                 packet->data[30],
 289                                 packet->data[31],
 290                                 packet->data[32],
 291                                 packet->data[33]);
 292
 293                 route_ipv4_unreachable(source, packet, ICMP_NET_UNKNOWN);
 294                 return;
 295         }
 296
 297         if(subnet->owner == source) {
 298                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Packet looping back to %s (%s)!"), source->name, source->hostname);
 299                 return;
 300         }
 301
 302         if(!subnet->owner->status.reachable)
 303                 route_ipv4_unreachable(source, packet, ICMP_NET_UNREACH);
 304
 305         if(priorityinheritance)
 306                 packet->priority = packet->data[15];
 307
 308         send_packet(subnet->owner, packet);
 309 }
 310
 311 static void route_ipv4(node_t *source, vpn_packet_t *packet)
 312 {
 313         cp();
 314
 315         if(!checklength(source, packet, ether_size + ip_size))
 316                 return;
 317
 318 #if 0
 319         if(packet->data[30] & 0xf0 == 0xe0) {
 320                 route_ipv4_multicast(source, packet);
 321                 return;
 322         }
 323 #endif
 324
 325         route_ipv4_unicast(source, packet);
 326 }
 327
 328 /* RFC 2463 */
 329
 330 static void route_ipv6_unreachable(node_t *source, vpn_packet_t *packet, uint8_t code)
 331 {
 332         struct ip6_hdr ip6;
 333         struct icmp6_hdr icmp6 = {0};
 334         uint16_t checksum;
 335
 336         struct {
 337                 struct in6_addr ip6_src;        /* source address */
 338                 struct in6_addr ip6_dst;        /* destination address */
 339                 uint32_t length;
 340                 uint32_t next;
 341         } pseudo;
 342
 343         if(ratelimit(3))
 344                 return;
 345
 346         cp();
 347
 348         /* Copy headers from packet to structs on the stack */
 349
 350         memcpy(&ip6, packet->data + ether_size, ip6_size);
 351
 352         /* Remember original source and destination */
 353
 354         pseudo.ip6_src = ip6.ip6_dst;
 355         pseudo.ip6_dst = ip6.ip6_src;
 356
 357         pseudo.length = packet->len - ether_size;
 358
 359         if(pseudo.length >= IP_MSS - ip6_size - icmp6_size)
 360                 pseudo.length = IP_MSS - ip6_size - icmp6_size;
 361
 362         /* Copy first part of original contents to ICMP message */
 363
 364         memmove(packet->data + ether_size + ip6_size + icmp6_size, packet->data + ether_size, pseudo.length);
 365
 366         /* Fill in IPv6 header */
 367
 368         ip6.ip6_flow = htonl(0x60000000UL);
 369         ip6.ip6_plen = htons(icmp6_size + pseudo.length);
 370         ip6.ip6_nxt = IPPROTO_ICMPV6;
 371         ip6.ip6_hlim = 255;
 372         ip6.ip6_src = pseudo.ip6_src;
 373         ip6.ip6_dst = pseudo.ip6_dst;
 374
 375         /* Fill in ICMP header */
 376
 377         icmp6.icmp6_type = ICMP6_DST_UNREACH;
 378         icmp6.icmp6_code = code;
 379         icmp6.icmp6_cksum = 0;
 380
 381         /* Create pseudo header */
 382
 383         pseudo.length = htonl(icmp6_size + pseudo.length);
 384         pseudo.next = htonl(IPPROTO_ICMPV6);
 385
 386         /* Generate checksum */
 387
 388         checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0);
 389         checksum = inet_checksum(&icmp6, icmp6_size, checksum);
 390         checksum = inet_checksum(packet->data + ether_size + ip6_size + icmp6_size, ntohl(pseudo.length) - icmp6_size, checksum);
 391
 392         icmp6.icmp6_cksum = checksum;
 393
 394         /* Copy structs on stack back to packet */
 395
 396         memcpy(packet->data + ether_size, &ip6, ip6_size);
 397         memcpy(packet->data + ether_size + ip6_size, &icmp6, icmp6_size);
 398
 399         packet->len = ether_size + ip6_size + ntohl(pseudo.length);
 400
 401         send_packet(source, packet);
 402 }
 403
 404 static void route_ipv6_unicast(node_t *source, vpn_packet_t *packet)
 405 {
 406         subnet_t *subnet;
 407
 408         cp();
 409
 410         subnet = lookup_subnet_ipv6((ipv6_t *) &packet->data[38]);
 411
 412         if(!subnet) {
 413                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet from %s (%s): unknown IPv6 destination address %hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx"),
 414                                 source->name, source->hostname,
 415                                 ntohs(*(uint16_t *) &packet->data[38]),
 416                                 ntohs(*(uint16_t *) &packet->data[40]),
 417                                 ntohs(*(uint16_t *) &packet->data[42]),
 418                                 ntohs(*(uint16_t *) &packet->data[44]),
 419                                 ntohs(*(uint16_t *) &packet->data[46]),
 420                                 ntohs(*(uint16_t *) &packet->data[48]),
 421                                 ntohs(*(uint16_t *) &packet->data[50]),
 422                                 ntohs(*(uint16_t *) &packet->data[52]));
 423
 424                 route_ipv6_unreachable(source, packet, ICMP6_DST_UNREACH_ADDR);
 425                 return;
 426         }
 427
 428         if(subnet->owner == source) {
 429                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Packet looping back to %s (%s)!"), source->name, source->hostname);
 430                 return;
 431         }
 432
 433         if(!subnet->owner->status.reachable)
 434                 route_ipv6_unreachable(source, packet, ICMP6_DST_UNREACH_NOROUTE);
 435
 436         send_packet(subnet->owner, packet);
 437 }
 438
 439 #ifdef ENABLE_MULTICAST
 440 static void route_ipv6_multicast(node_t *source, vpn_packet_t *packet)
 441 {
 442         avl_node_t *node;
 443         subnet_t *subnet, search = {0};
 444
 445         cp();
 446
 447         search.type = SUBNET_IPV6;
 448         search.net.ipv6.address = *(ipv6_t *)(packet->data + ether_size + ip6_size + icmp6_size);
 449         search.net.ipv6.prefixlength = 128;
 450         search.owner = NULL;
 451
 452         ifdebug(TRAFFIC) logger(LOG_INFO, _("Multicasting packet of %d bytes from %s (%s)"), packet->len, source->name, source->hostname);
 453
 454         for(node = avl_search_closest_smaller_node(myself->subnet_tree, &search); node; node = node->next) {
 455                 subnet = node->data;
 456
 457                 if(subnet->type != SUBNET_IPV6 || memcmp(&subnet->net.ipv6.address, packet->data + ether_size + ip6_size + icmp6_size, sizeof(ipv6_t)))
 458                         break;
 459
 460                 if(subnet->owner != source)
 461                         send_packet(subnet->owner, packet);
 462         }
 463 }
 464 #endif
 465
 466 /* RFC 2461 */
 467
 468 static void route_neighborsol(node_t *source, vpn_packet_t *packet)
 469 {
 470         struct ip6_hdr ip6;
 471         struct nd_neighbor_solicit ns;
 472         struct nd_opt_hdr opt;
 473         subnet_t *subnet;
 474         uint16_t checksum;
 475
 476         struct {
 477                 struct in6_addr ip6_src;        /* source address */
 478                 struct in6_addr ip6_dst;        /* destination address */
 479                 uint32_t length;
 480                 uint32_t next;
 481         } pseudo;
 482
 483         cp();
 484
 485         if(!checklength(source, packet, ether_size + ip6_size + ns_size + opt_size + ETH_ALEN))
 486                 return;
 487
 488         if(source != myself) {
 489                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Got neighbor solicitation request from %s (%s) while in router mode!"), source->name, source->hostname);
 490                 return;
 491         }
 492
 493         /* Copy headers from packet to structs on the stack */
 494
 495         memcpy(&ip6, packet->data + ether_size, ip6_size);
 496         memcpy(&ns, packet->data + ether_size + ip6_size, ns_size);
 497         memcpy(&opt, packet->data + ether_size + ip6_size + ns_size, opt_size);
 498
 499         /* First, snatch the source address from the neighbor solicitation packet */
 500
 501         if(overwrite_mac)
 502                 memcpy(mymac.x, packet->data + ETH_ALEN, ETH_ALEN);
 503
 504         /* Check if this is a valid neighbor solicitation request */
 505
 506         if(ns.nd_ns_hdr.icmp6_type != ND_NEIGHBOR_SOLICIT ||
 507            opt.nd_opt_type != ND_OPT_SOURCE_LINKADDR) {
 508                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: received unknown type neighbor solicitation request"));
 509                 return;
 510         }
 511
 512         /* Create pseudo header */
 513
 514         pseudo.ip6_src = ip6.ip6_src;
 515         pseudo.ip6_dst = ip6.ip6_dst;
 516         pseudo.length = htonl(ns_size + opt_size + ETH_ALEN);
 517         pseudo.next = htonl(IPPROTO_ICMPV6);
 518
 519         /* Generate checksum */
 520
 521         checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0);
 522         checksum = inet_checksum(&ns, ns_size, checksum);
 523         checksum = inet_checksum(&opt, opt_size, checksum);
 524         checksum = inet_checksum(packet->data + ether_size + ip6_size + ns_size + opt_size, ETH_ALEN, checksum);
 525
 526         if(checksum) {
 527                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: checksum error for neighbor solicitation request"));
 528                 return;
 529         }
 530
 531         /* Check if the IPv6 address exists on the VPN */
 532
 533         subnet = lookup_subnet_ipv6((ipv6_t *) &ns.nd_ns_target);
 534
 535         if(!subnet) {
 536                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: neighbor solicitation request for unknown address %hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx"),
 537                                    ntohs(((uint16_t *) &ns.nd_ns_target)[0]),
 538                                    ntohs(((uint16_t *) &ns.nd_ns_target)[1]),
 539                                    ntohs(((uint16_t *) &ns.nd_ns_target)[2]),
 540                                    ntohs(((uint16_t *) &ns.nd_ns_target)[3]),
 541                                    ntohs(((uint16_t *) &ns.nd_ns_target)[4]),
 542                                    ntohs(((uint16_t *) &ns.nd_ns_target)[5]),
 543                                    ntohs(((uint16_t *) &ns.nd_ns_target)[6]),
 544                                    ntohs(((uint16_t *) &ns.nd_ns_target)[7]));
 545
 546                 return;
 547         }
 548
 549         /* Check if it is for our own subnet */
 550
 551         if(subnet->owner == myself)
 552                 return;                                 /* silently ignore */
 553
 554         /* Create neighbor advertation reply */
 555
 556         memcpy(packet->data, packet->data + ETH_ALEN, ETH_ALEN);        /* copy destination address */
 557         packet->data[ETH_ALEN * 2 - 1] ^= 0xFF; /* mangle source address so it looks like it's not from us */
 558
 559         ip6.ip6_dst = ip6.ip6_src;                      /* swap destination and source protocoll address */
 560         ip6.ip6_src = ns.nd_ns_target;
 561
 562         memcpy(packet->data + ether_size + ip6_size + ns_size + opt_size, packet->data + ETH_ALEN, ETH_ALEN);   /* add fake source hard addr */
 563
 564         ns.nd_ns_cksum = 0;
 565         ns.nd_ns_type = ND_NEIGHBOR_ADVERT;
 566         ns.nd_ns_reserved = htonl(0x40000000UL);        /* Set solicited flag */
 567         opt.nd_opt_type = ND_OPT_TARGET_LINKADDR;
 568
 569         /* Create pseudo header */
 570
 571         pseudo.ip6_src = ip6.ip6_src;
 572         pseudo.ip6_dst = ip6.ip6_dst;
 573         pseudo.length = htonl(ns_size + opt_size + ETH_ALEN);
 574         pseudo.next = htonl(IPPROTO_ICMPV6);
 575
 576         /* Generate checksum */
 577
 578         checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0);
 579         checksum = inet_checksum(&ns, ns_size, checksum);
 580         checksum = inet_checksum(&opt, opt_size, checksum);
 581         checksum = inet_checksum(packet->data + ether_size + ip6_size + ns_size + opt_size, ETH_ALEN, checksum);
 582
 583         ns.nd_ns_hdr.icmp6_cksum = checksum;
 584
 585         /* Copy structs on stack back to packet */
 586
 587         memcpy(packet->data + ether_size, &ip6, ip6_size);
 588         memcpy(packet->data + ether_size + ip6_size, &ns, ns_size);
 589         memcpy(packet->data + ether_size + ip6_size + ns_size, &opt, opt_size);
 590
 591         send_packet(source, packet);
 592 }
 593
 594 /* RFC 2710 */
 595
 596 #ifdef ENABLE_MULTICAST
 597 static void route_membershipreport(node_t *source, vpn_packet_t *packet)
 598 {
 599         struct ip6_hdr ip6;
 600         struct icmp6_hdr icmp6;
 601         subnet_t *subnet, search = {0};
 602         uint16_t checksum;
 603
 604         struct {
 605                 struct in6_addr ip6_src;        /* source address */
 606                 struct in6_addr ip6_dst;        /* destination address */
 607                 uint32_t length;
 608                 uint32_t next;
 609         } pseudo;
 610
 611         cp();
 612
 613         if(!checklength(source, packet, ether_size + ip6_size + icmp6_size + sizeof(ipv6_t)))
 614                 return;
 615
 616         if(source != myself) {
 617                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Got membership report from %s (%s) while in router mode!"), source->name, source->hostname);
 618                 return;
 619         }
 620
 621         /* Copy headers from packet to structs on the stack */
 622
 623         memcpy(&ip6, packet->data + ether_size, ip6_size);
 624         memcpy(&icmp6, packet->data + ether_size + ip6_size + 8, icmp6_size);
 625
 626         /* Create pseudo header */
 627
 628         pseudo.ip6_src = ip6.ip6_src;
 629         pseudo.ip6_dst = ip6.ip6_dst;
 630         pseudo.length = htonl(icmp6_size + sizeof(ipv6_t));
 631         pseudo.next = htonl(IPPROTO_ICMPV6);
 632
 633         /* Generate checksum */
 634
 635         checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0);
 636         checksum = inet_checksum(&icmp6, icmp6_size, checksum);
 637         checksum = inet_checksum(packet->data + ether_size + ip6_size + 8 + icmp6_size, sizeof(ipv6_t), checksum);
 638
 639         if(checksum) {
 640                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: checksum error for membership report"));
 641                 return;
 642         }
 643
 644         /* Check if the IPv6 address exists on the VPN */
 645
 646         search.type = SUBNET_IPV6;
 647         search.net.ipv6.address = *(ipv6_t *)(packet->data + ether_size + ip6_size + 8 + icmp6_size);
 648         search.net.ipv6.prefixlength = 128;
 649         search.owner = myself;
 650
 651         subnet = avl_search(myself->subnet_tree, &search);
 652
 653         if(!subnet) {
 654                 avl_node_t *node;
 655                 connection_t *c;
 656
 657                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Learned new IPv6 multicast address %hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx"),
 658                                 ntohs(*(uint16_t *) &packet->data[70]),
 659                                 ntohs(*(uint16_t *) &packet->data[72]),
 660                                 ntohs(*(uint16_t *) &packet->data[74]),
 661                                 ntohs(*(uint16_t *) &packet->data[76]),
 662                                 ntohs(*(uint16_t *) &packet->data[78]),
 663                                 ntohs(*(uint16_t *) &packet->data[80]),
 664                                 ntohs(*(uint16_t *) &packet->data[82]),
 665                                 ntohs(*(uint16_t *) &packet->data[84]));
 666
 667                 subnet = new_subnet();
 668                 subnet->type = SUBNET_IPV6;
 669                 subnet->net.ipv6.address = *(ipv6_t *)(packet->data + ether_size + ip6_size + 8 + icmp6_size);
 670                 subnet->net.ipv6.prefixlength = 128;
 671                 subnet->expires = now + multicastexpire;
 672                 subnet_add(myself, subnet);
 673
 674                 /* And tell all other tinc daemons it's ours */
 675
 676                 for(node = connection_tree->head; node; node = node->next) {
 677                         c = node->data;
 678                         if(c->status.active)
 679                                 send_add_subnet(c, subnet);
 680                 }
 681         }
 682
 683         if(subnet->expires)
 684                 subnet->expires = now + multicastexpire;
 685 }
 686 #endif
 687
 688 static void route_ipv6(node_t *source, vpn_packet_t *packet)
 689 {
 690         cp();
 691
 692         if(!checklength(source, packet, ether_size + ip6_size))
 693                 return;
 694
 695         if(packet->data[20] == IPPROTO_ICMPV6 && checklength(source, packet, ether_size + ip6_size + icmp6_size) && packet->data[54] == ND_NEIGHBOR_SOLICIT) {
 696                 route_neighborsol(source, packet);
 697                 return;
 698         }
 699
 700 #ifdef ENABLE_MULTICAST
 701         if(packet->data[20] == IPPROTO_HOPOPTS && checklength(source, packet, ether_size + ip6_size + 8)
 702                         && packet->data[54] == IPPROTO_ICMPV6 && checklength(source, packet, ether_size + ip6_size + 8 + icmp6_size)
 703                         && packet->data[62] == ICMP6_MEMBERSHIP_REPORT) {
 704                 route_membershipreport(source, packet);
 705                 return;
 706         }
 707
 708         if(packet->data[38] == 0xff && packet->data[39] & 0x0c) {
 709                 route_ipv6_multicast(source, packet);
 710                 return;
 711         }
 712 #endif
 713
 714         route_ipv6_unicast(source, packet);
 715 }
 716
 717 /* RFC 826 */
 718
 719 static void route_arp(node_t *source, vpn_packet_t *packet)
 720 {
 721         struct ether_arp arp;
 722         subnet_t *subnet;
 723         struct in_addr addr;
 724
 725         cp();
 726
 727         if(!checklength(source, packet, ether_size + arp_size))
 728                 return;
 729
 730         if(source != myself) {
 731                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Got ARP request from %s (%s) while in router mode!"), source->name, source->hostname);
 732                 return;
 733         }
 734
 735         /* First, snatch the source address from the ARP packet */
 736
 737         if(overwrite_mac)
 738                 memcpy(mymac.x, packet->data + ETH_ALEN, ETH_ALEN);
 739
 740         /* Copy headers from packet to structs on the stack */
 741
 742         memcpy(&arp, packet->data + ether_size, arp_size);
 743
 744         /* Check if this is a valid ARP request */
 745
 746         if(ntohs(arp.arp_hrd) != ARPHRD_ETHER || ntohs(arp.arp_pro) != ETH_P_IP ||
 747            arp.arp_hln != ETH_ALEN || arp.arp_pln != sizeof(addr) || ntohs(arp.arp_op) != ARPOP_REQUEST) {
 748                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: received unknown type ARP request"));
 749                 return;
 750         }
 751
 752         /* Check if the IPv4 address exists on the VPN */
 753
 754         subnet = lookup_subnet_ipv4((ipv4_t *) &arp.arp_tpa);
 755
 756         if(!subnet) {
 757                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: ARP request for unknown address %d.%d.%d.%d"),
 758                                    arp.arp_tpa[0], arp.arp_tpa[1], arp.arp_tpa[2],
 759                                    arp.arp_tpa[3]);
 760                 return;
 761         }
 762
 763         /* Check if it is for our own subnet */
 764
 765         if(subnet->owner == myself)
 766                 return;                                 /* silently ignore */
 767
 768         memcpy(packet->data, packet->data + ETH_ALEN, ETH_ALEN);        /* copy destination address */
 769         packet->data[ETH_ALEN * 2 - 1] ^= 0xFF; /* mangle source address so it looks like it's not from us */
 770
 771         memcpy(&addr, arp.arp_tpa, sizeof(addr));       /* save protocol addr */
 772         memcpy(arp.arp_tpa, arp.arp_spa, sizeof(addr)); /* swap destination and source protocol address */
 773         memcpy(arp.arp_spa, &addr, sizeof(addr));       /* ... */
 774
 775         memcpy(arp.arp_tha, arp.arp_sha, ETH_ALEN);     /* set target hard/proto addr */
 776         memcpy(arp.arp_sha, packet->data + ETH_ALEN, ETH_ALEN); /* add fake source hard addr */
 777         arp.arp_op = htons(ARPOP_REPLY);
 778
 779         /* Copy structs on stack back to packet */
 780
 781         memcpy(packet->data + ether_size, &arp, arp_size);
 782
 783         send_packet(source, packet);
 784 }
 785
 786 void route(node_t *source, vpn_packet_t *packet)
 787 {
 788         cp();
 789
 790         if(!checklength(source, packet, ether_size))
 791                 return;
 792
 793         switch (routing_mode) {
 794                 case RMODE_ROUTER:
 795                         {
 796                                 uint16_t type;
 797
 798                                 type = ntohs(*((uint16_t *)(&packet->data[12])));
 799                                 switch (type) {
 800                                         case ETH_P_ARP:
 801                                                 route_arp(source, packet);
 802                                                 break;
 803
 804                                         case ETH_P_IP:
 805                                                 route_ipv4(source, packet);
 806                                                 break;
 807
 808                                         case ETH_P_IPV6:
 809                                                 route_ipv6(source, packet);
 810                                                 break;
 811
 812                                         default:
 813                                                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet from %s (%s): unknown type %hx"), source->name, source->hostname, type);
 814                                                 break;
 815                                 }
 816                         }
 817                         break;
 818
 819                 case RMODE_SWITCH:
 820                         route_mac(source, packet);
 821                         break;
 822
 823                 case RMODE_HUB:
 824                         broadcast_packet(source, packet);
 825                         break;
 826         }
 827 }