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 1.1.2.68 2003/10/06 13:57:12 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 "device.h"
  44 #include "ethernet.h"
  45 #include "ipv4.h"
  46 #include "ipv6.h"
  47 #include "logger.h"
  48 #include "net.h"
  49 #include "protocol.h"
  50 #include "route.h"
  51 #include "subnet.h"
  52 #include "utils.h"
  53
  54 rmode_t routing_mode = RMODE_ROUTER;
  55 bool priorityinheritance = false;
  56 int macexpire = 600;
  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 += *(unsigned char *)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 void learn_mac(mac_t *address)
 108 {
 109         subnet_t *subnet;
 110         avl_node_t *node;
 111         connection_t *c;
 112
 113         cp();
 114
 115         subnet = lookup_subnet_mac(address);
 116
 117         /* If we don't know this MAC address yet, store it */
 118
 119         if(!subnet || subnet->owner != myself) {
 120                 ifdebug(TRAFFIC) logger(LOG_INFO, _("Learned new MAC address %hx:%hx:%hx:%hx:%hx:%hx"),
 121                                    address->x[0], address->x[1], address->x[2], address->x[3],
 122                                    address->x[4], address->x[5]);
 123
 124                 subnet = new_subnet();
 125                 subnet->type = SUBNET_MAC;
 126                 memcpy(&subnet->net.mac.address, address, sizeof(mac_t));
 127                 subnet_add(myself, subnet);
 128
 129                 /* And tell all other tinc daemons it's our MAC */
 130
 131                 for(node = connection_tree->head; node; node = node->next) {
 132                         c = node->data;
 133                         if(c->status.active)
 134                                 send_add_subnet(c, subnet);
 135                 }
 136         }
 137
 138         subnet->net.mac.lastseen = now;
 139 }
 140
 141 void age_mac(void)
 142 {
 143         subnet_t *s;
 144         connection_t *c;
 145         avl_node_t *node, *next, *node2;
 146
 147         cp();
 148
 149         for(node = myself->subnet_tree->head; node; node = next) {
 150                 next = node->next;
 151                 s = node->data;
 152                 if(s->type == SUBNET_MAC && s->net.mac.lastseen && s->net.mac.lastseen + macexpire < now) {
 153                         ifdebug(TRAFFIC) logger(LOG_INFO, _("MAC address %hx:%hx:%hx:%hx:%hx:%hx expired"),
 154                                            s->net.mac.address.x[0], s->net.mac.address.x[1],
 155                                            s->net.mac.address.x[2], s->net.mac.address.x[3],
 156                                            s->net.mac.address.x[4], s->net.mac.address.x[5]);
 157
 158                         for(node2 = connection_tree->head; node2; node2 = node2->next) {
 159                                 c = node2->data;
 160                                 if(c->status.active)
 161                                         send_del_subnet(c, s);
 162                         }
 163
 164                         subnet_del(myself, s);
 165                 }
 166         }
 167 }
 168
 169 static node_t *route_mac(vpn_packet_t *packet)
 170 {
 171         subnet_t *subnet;
 172
 173         cp();
 174
 175         /* Learn source address */
 176
 177         learn_mac((mac_t *)(&packet->data[6]));
 178
 179         /* Lookup destination address */
 180
 181         subnet = lookup_subnet_mac((mac_t *)(&packet->data[0]));
 182
 183         if(subnet)
 184                 return subnet->owner;
 185         else
 186                 return NULL;
 187 }
 188
 189 /* RFC 792 */
 190
 191 static void route_ipv4_unreachable(vpn_packet_t *packet, uint8_t code)
 192 {
 193         struct ip ip;
 194         struct icmp icmp;
 195
 196         struct in_addr ip_src;
 197         struct in_addr ip_dst;
 198         uint32_t oldlen;
 199
 200         if(ratelimit(3))
 201                 return;
 202
 203         cp();
 204
 205         /* Copy headers from packet into properly aligned structs on the stack */
 206
 207         memcpy(&ip, packet->data + ether_size, ip_size);
 208         memcpy(&icmp, packet->data + ether_size + ip_size, icmp_size);
 209
 210         /* Remember original source and destination */
 211
 212         memcpy(&ip_src, &ip.ip_src, sizeof(ip_src));
 213         memcpy(&ip_dst, &ip.ip_dst, sizeof(ip_dst));
 214
 215         oldlen = packet->len - ether_size;
 216
 217         if(oldlen >= IP_MSS - ip_size - icmp_size)
 218                 oldlen = IP_MSS - ip_size - icmp_size;
 219
 220         /* Copy first part of original contents to ICMP message */
 221
 222         memmove(packet->data + ether_size + ip_size + icmp_size, packet->data + ether_size, oldlen);
 223
 224         /* Fill in IPv4 header */
 225
 226         ip.ip_v = 4;
 227         ip.ip_hl = ip_size / 4;
 228         ip.ip_tos = 0;
 229         ip.ip_len = htons(ip_size + icmp_size + oldlen);
 230         ip.ip_id = 0;
 231         ip.ip_off = 0;
 232         ip.ip_ttl = 255;
 233         ip.ip_p = IPPROTO_ICMP;
 234         ip.ip_sum = 0;
 235         memcpy(&ip.ip_src, &ip_dst, sizeof(ip_src));
 236         memcpy(&ip.ip_dst, &ip_src, sizeof(ip_dst));
 237
 238         ip.ip_sum = inet_checksum(&ip, ip_size, ~0);
 239
 240         /* Fill in ICMP header */
 241
 242         icmp.icmp_type = ICMP_DEST_UNREACH;
 243         icmp.icmp_code = code;
 244         icmp.icmp_cksum = 0;
 245
 246         icmp.icmp_cksum = inet_checksum(&icmp, icmp_size, ~0);
 247         icmp.icmp_cksum = inet_checksum(packet->data + ether_size + ip_size + icmp_size, oldlen, icmp.icmp_cksum);
 248
 249         /* Copy structs on stack back to packet */
 250
 251         memcpy(packet->data + ether_size, &ip, ip_size);
 252         memcpy(packet->data + ether_size + ip_size, &icmp, icmp_size);
 253
 254         packet->len = ether_size + ip_size + icmp_size + oldlen;
 255
 256         write_packet(packet);
 257 }
 258
 259 static node_t *route_ipv4(vpn_packet_t *packet)
 260 {
 261         subnet_t *subnet;
 262
 263         cp();
 264
 265         if(priorityinheritance)
 266                 packet->priority = packet->data[15];
 267
 268         subnet = lookup_subnet_ipv4((ipv4_t *) &packet->data[30]);
 269
 270         if(!subnet) {
 271                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: unknown IPv4 destination address %d.%d.%d.%d"),
 272                                    packet->data[30], packet->data[31], packet->data[32],
 273                                    packet->data[33]);
 274
 275                 route_ipv4_unreachable(packet, ICMP_NET_UNKNOWN);
 276                 return NULL;
 277         }
 278
 279         if(!subnet->owner->status.reachable)
 280                 route_ipv4_unreachable(packet, ICMP_NET_UNREACH);
 281
 282         return subnet->owner;
 283 }
 284
 285 /* RFC 2463 */
 286
 287 static void route_ipv6_unreachable(vpn_packet_t *packet, uint8_t code)
 288 {
 289         struct ip6_hdr ip6;
 290         struct icmp6_hdr icmp6;
 291         uint16_t checksum;
 292
 293         struct {
 294                 struct in6_addr ip6_src;        /* source address */
 295                 struct in6_addr ip6_dst;        /* destination address */
 296                 uint32_t length;
 297                 uint32_t next;
 298         } pseudo;
 299
 300         if(ratelimit(3))
 301                 return;
 302
 303         cp();
 304
 305         /* Copy headers from packet to structs on the stack */
 306
 307         memcpy(&ip6, packet->data + ether_size, ip6_size);
 308         memcpy(&icmp6, packet->data + ether_size + ip6_size, icmp6_size);
 309
 310         /* Remember original source and destination */
 311
 312         memcpy(&pseudo.ip6_src, &ip6.ip6_dst, sizeof(ip6.ip6_src));
 313         memcpy(&pseudo.ip6_dst, &ip6.ip6_src, sizeof(ip6.ip6_dst));
 314
 315         pseudo.length = ntohs(ip6.ip6_plen) + ip6_size;
 316
 317         if(pseudo.length >= IP_MSS - ip6_size - icmp6_size)
 318                 pseudo.length = IP_MSS - ip6_size - icmp6_size;
 319
 320         /* Copy first part of original contents to ICMP message */
 321
 322         memmove(packet->data + ether_size + ip6_size + icmp6_size, packet->data + ether_size, pseudo.length);
 323
 324         /* Fill in IPv6 header */
 325
 326         ip6.ip6_flow = htonl(0x60000000UL);
 327         ip6.ip6_plen = htons(icmp6_size + pseudo.length);
 328         ip6.ip6_nxt = IPPROTO_ICMPV6;
 329         ip6.ip6_hlim = 255;
 330         memcpy(&ip6.ip6_src, &pseudo.ip6_src, sizeof(ip6.ip6_src));
 331         memcpy(&ip6.ip6_dst, &pseudo.ip6_dst, sizeof(ip6.ip6_dst));
 332
 333         /* Fill in ICMP header */
 334
 335         icmp6.icmp6_type = ICMP6_DST_UNREACH;
 336         icmp6.icmp6_code = code;
 337         icmp6.icmp6_cksum = 0;
 338
 339         /* Create pseudo header */
 340
 341         pseudo.length = htonl(icmp6_size + pseudo.length);
 342         pseudo.next = htonl(IPPROTO_ICMPV6);
 343
 344         /* Generate checksum */
 345
 346         checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0);
 347         checksum = inet_checksum(&icmp6, icmp6_size, checksum);
 348         checksum = inet_checksum(packet->data + ether_size + ip6_size + icmp6_size, ntohl(pseudo.length) - icmp6_size, checksum);
 349
 350         icmp6.icmp6_cksum = checksum;
 351
 352         /* Copy structs on stack back to packet */
 353
 354         memcpy(packet->data + ether_size, &ip6, ip6_size);
 355         memcpy(packet->data + ether_size + ip6_size, &icmp6, icmp6_size);
 356
 357         packet->len = ether_size + ip6_size + ntohl(pseudo.length);
 358
 359         write_packet(packet);
 360 }
 361
 362 static node_t *route_ipv6(vpn_packet_t *packet)
 363 {
 364         subnet_t *subnet;
 365
 366         cp();
 367
 368         subnet = lookup_subnet_ipv6((ipv6_t *) &packet->data[38]);
 369
 370         if(!subnet) {
 371                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: unknown IPv6 destination address %hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx"),
 372                                    ntohs(*(uint16_t *) &packet->data[38]),
 373                                    ntohs(*(uint16_t *) &packet->data[40]),
 374                                    ntohs(*(uint16_t *) &packet->data[42]),
 375                                    ntohs(*(uint16_t *) &packet->data[44]),
 376                                    ntohs(*(uint16_t *) &packet->data[46]),
 377                                    ntohs(*(uint16_t *) &packet->data[48]),
 378                                    ntohs(*(uint16_t *) &packet->data[50]),
 379                                    ntohs(*(uint16_t *) &packet->data[52]));
 380                 route_ipv6_unreachable(packet, ICMP6_DST_UNREACH_ADDR);
 381
 382                 return NULL;
 383         }
 384
 385         if(!subnet->owner->status.reachable)
 386                 route_ipv6_unreachable(packet, ICMP6_DST_UNREACH_NOROUTE);
 387
 388         return subnet->owner;
 389 }
 390
 391 /* RFC 2461 */
 392
 393 static void route_neighborsol(vpn_packet_t *packet)
 394 {
 395         struct ip6_hdr ip6;
 396         struct nd_neighbor_solicit ns;
 397         struct nd_opt_hdr opt;
 398         subnet_t *subnet;
 399         uint16_t checksum;
 400
 401         struct {
 402                 struct in6_addr ip6_src;        /* source address */
 403                 struct in6_addr ip6_dst;        /* destination address */
 404                 uint32_t length;
 405                 uint32_t next;
 406         } pseudo;
 407
 408         cp();
 409
 410         /* Copy headers from packet to structs on the stack */
 411
 412         memcpy(&ip6, packet->data + ether_size, ip6_size);
 413         memcpy(&ns, packet->data + ether_size + ip6_size, ns_size);
 414         memcpy(&opt, packet->data + ether_size + ip6_size + ns_size, opt_size);
 415
 416         /* First, snatch the source address from the neighbor solicitation packet */
 417
 418         if(overwrite_mac)
 419                 memcpy(mymac.x, packet->data + ETH_ALEN, ETH_ALEN);
 420
 421         /* Check if this is a valid neighbor solicitation request */
 422
 423         if(ns.nd_ns_hdr.icmp6_type != ND_NEIGHBOR_SOLICIT ||
 424            opt.nd_opt_type != ND_OPT_SOURCE_LINKADDR) {
 425                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: received unknown type neighbor solicitation request"));
 426                 return;
 427         }
 428
 429         /* Create pseudo header */
 430
 431         memcpy(&pseudo.ip6_src, &ip6.ip6_src, sizeof(ip6.ip6_src));
 432         memcpy(&pseudo.ip6_dst, &ip6.ip6_dst, sizeof(ip6.ip6_dst));
 433         pseudo.length = htonl(ns_size + opt_size + ETH_ALEN);
 434         pseudo.next = htonl(IPPROTO_ICMPV6);
 435
 436         /* Generate checksum */
 437
 438         checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0);
 439         checksum = inet_checksum(&ns, ns_size, checksum);
 440         checksum = inet_checksum(&opt, opt_size, checksum);
 441
 442         if(checksum) {
 443                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: checksum error for neighbor solicitation request"));
 444                 return;
 445         }
 446
 447         /* Check if the IPv6 address exists on the VPN */
 448
 449         subnet = lookup_subnet_ipv6((ipv6_t *) &ns.nd_ns_target);
 450
 451         if(!subnet) {
 452                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: neighbor solicitation request for unknown address %hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx"),
 453                                    ntohs(((uint16_t *) &ns.nd_ns_target)[0]),
 454                                    ntohs(((uint16_t *) &ns.nd_ns_target)[1]),
 455                                    ntohs(((uint16_t *) &ns.nd_ns_target)[2]),
 456                                    ntohs(((uint16_t *) &ns.nd_ns_target)[3]),
 457                                    ntohs(((uint16_t *) &ns.nd_ns_target)[4]),
 458                                    ntohs(((uint16_t *) &ns.nd_ns_target)[5]),
 459                                    ntohs(((uint16_t *) &ns.nd_ns_target)[6]),
 460                                    ntohs(((uint16_t *) &ns.nd_ns_target)[7]));
 461
 462                 return;
 463         }
 464
 465         /* Check if it is for our own subnet */
 466
 467         if(subnet->owner == myself)
 468                 return;                                 /* silently ignore */
 469
 470         /* Create neighbor advertation reply */
 471
 472         memcpy(packet->data, packet->data + ETH_ALEN, ETH_ALEN);        /* copy destination address */
 473         packet->data[ETH_ALEN * 2 - 1] ^= 0xFF; /* mangle source address so it looks like it's not from us */
 474
 475         memcpy(&ip6.ip6_src, &ns.nd_ns_target, sizeof(ip6.ip6_src));    /* swap destination and source protocol address */
 476         memcpy(&ip6.ip6_dst, &ip6.ip6_src, sizeof(ip6.ip6_dst));        /* ... */
 477
 478         memcpy(&opt + opt_size, packet->data + ETH_ALEN, ETH_ALEN);     /* add fake source hard addr */
 479
 480         ns.nd_ns_cksum = 0;
 481         ns.nd_ns_type = ND_NEIGHBOR_ADVERT;
 482         ns.nd_ns_reserved = htonl(0x40000000UL);        /* Set solicited flag */
 483         opt.nd_opt_type = ND_OPT_TARGET_LINKADDR;
 484
 485         /* Create pseudo header */
 486
 487         memcpy(&pseudo.ip6_src, &ip6.ip6_src, sizeof(ip6.ip6_src));
 488         memcpy(&pseudo.ip6_dst, &ip6.ip6_dst, sizeof(ip6.ip6_dst));
 489         pseudo.length = htonl(ns_size + opt_size + ETH_ALEN);
 490         pseudo.next = htonl(IPPROTO_ICMPV6);
 491
 492         /* Generate checksum */
 493
 494         checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0);
 495         checksum = inet_checksum(&ns, ns_size, checksum);
 496         checksum = inet_checksum(&opt, opt_size, checksum);
 497
 498         ns.nd_ns_hdr.icmp6_cksum = checksum;
 499
 500         /* Copy structs on stack back to packet */
 501
 502         memcpy(packet->data + ether_size, &ip6, ip6_size);
 503         memcpy(packet->data + ether_size + ip6_size, &ns, ns_size);
 504         memcpy(packet->data + ether_size + ip6_size + ns_size, &opt, opt_size);
 505
 506         write_packet(packet);
 507 }
 508
 509 /* RFC 826 */
 510
 511 static void route_arp(vpn_packet_t *packet)
 512 {
 513         struct ether_arp arp;
 514         subnet_t *subnet;
 515         struct in_addr addr;
 516
 517         cp();
 518
 519         /* First, snatch the source address from the ARP packet */
 520
 521         if(overwrite_mac)
 522                 memcpy(mymac.x, packet->data + ETH_ALEN, ETH_ALEN);
 523
 524         /* Copy headers from packet to structs on the stack */
 525
 526         memcpy(&arp, packet->data + ether_size, arp_size);
 527
 528         /* Check if this is a valid ARP request */
 529
 530         if(ntohs(arp.arp_hrd) != ARPHRD_ETHER || ntohs(arp.arp_pro) != ETH_P_IP ||
 531            arp.arp_hln != ETH_ALEN || arp.arp_pln != sizeof(addr) || ntohs(arp.arp_op) != ARPOP_REQUEST) {
 532                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: received unknown type ARP request"));
 533                 return;
 534         }
 535
 536         /* Check if the IPv4 address exists on the VPN */
 537
 538         subnet = lookup_subnet_ipv4((ipv4_t *) &arp.arp_tpa);
 539
 540         if(!subnet) {
 541                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: ARP request for unknown address %d.%d.%d.%d"),
 542                                    arp.arp_tpa[0], arp.arp_tpa[1], arp.arp_tpa[2],
 543                                    arp.arp_tpa[3]);
 544                 return;
 545         }
 546
 547         /* Check if it is for our own subnet */
 548
 549         if(subnet->owner == myself)
 550                 return;                                 /* silently ignore */
 551
 552         memcpy(packet->data, packet->data + ETH_ALEN, ETH_ALEN);        /* copy destination address */
 553         packet->data[ETH_ALEN * 2 - 1] ^= 0xFF; /* mangle source address so it looks like it's not from us */
 554
 555         memcpy(&addr, arp.arp_tpa, sizeof(addr));       /* save protocol addr */
 556         memcpy(arp.arp_tpa, arp.arp_spa, sizeof(addr)); /* swap destination and source protocol address */
 557         memcpy(arp.arp_spa, &addr, sizeof(addr));       /* ... */
 558
 559         memcpy(arp.arp_tha, arp.arp_sha, ETH_ALEN);     /* set target hard/proto addr */
 560         memcpy(arp.arp_sha, packet->data + ETH_ALEN, ETH_ALEN); /* add fake source hard addr */
 561         arp.arp_op = htons(ARPOP_REPLY);
 562
 563         /* Copy structs on stack back to packet */
 564
 565         memcpy(packet->data + ether_size, &arp, arp_size);
 566
 567         write_packet(packet);
 568 }
 569
 570 void route_outgoing(vpn_packet_t *packet)
 571 {
 572         uint16_t type;
 573         node_t *n = NULL;
 574
 575         cp();
 576
 577         if(packet->len < ether_size) {
 578                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Read too short packet"));
 579                 return;
 580         }
 581
 582         /* FIXME: multicast? */
 583
 584         switch (routing_mode) {
 585                 case RMODE_ROUTER:
 586                         type = ntohs(*((uint16_t *)(&packet->data[12])));
 587                         switch (type) {
 588                                 case ETH_P_IP:
 589                                         if(packet->len < ether_size + ip_size) {
 590                                                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Read too short packet"));
 591                                                 return;
 592                                         }
 593
 594                                         n = route_ipv4(packet);
 595                                         break;
 596
 597                                 case ETH_P_IPV6:
 598                                         if(packet->len < ether_size + ip6_size) {
 599                                                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Read too short packet"));
 600                                                 return;
 601                                         }
 602
 603                                         if(packet->data[20] == IPPROTO_ICMPV6 && packet->len >= ether_size + ip6_size + ns_size && packet->data[54] == ND_NEIGHBOR_SOLICIT) {
 604                                                 route_neighborsol(packet);
 605                                                 return;
 606                                         }
 607                                         n = route_ipv6(packet);
 608                                         break;
 609
 610                                 case ETH_P_ARP:
 611                                         if(packet->len < ether_size + arp_size) {
 612                                                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Read too short packet"));
 613                                                 return;
 614                                         }
 615
 616                                         route_arp(packet);
 617                                         return;
 618
 619                                 default:
 620                                         ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: unknown type %hx"), type);
 621                                         return;
 622                         }
 623                         if(n)
 624                                 send_packet(n, packet);
 625                         break;
 626
 627                 case RMODE_SWITCH:
 628                         n = route_mac(packet);
 629                         if(n)
 630                                 send_packet(n, packet);
 631                         else
 632                                 broadcast_packet(myself, packet);
 633                         break;
 634
 635                 case RMODE_HUB:
 636                         broadcast_packet(myself, packet);
 637                         break;
 638         }
 639 }
 640
 641 void route_incoming(node_t *source, vpn_packet_t *packet)
 642 {
 643         if(packet->len < ether_size) {
 644                 ifdebug(TRAFFIC) logger(LOG_WARNING, _("Read too short packet"));
 645                 return;
 646         }
 647
 648         switch (routing_mode) {
 649                 case RMODE_ROUTER:
 650                         {
 651                                 node_t *n = NULL;
 652                                 uint16_t type;
 653
 654                                 type = ntohs(*((uint16_t *)(&packet->data[12])));
 655                                 switch (type) {
 656                                         case ETH_P_IP:
 657                                                 if(packet->len < ether_size + ip_size) {
 658                                                         ifdebug(TRAFFIC) logger(LOG_WARNING, _("Read too short packet"));
 659                                                         return;
 660                                                 }
 661
 662                                                 n = route_ipv4(packet);
 663                                                 break;
 664
 665                                         case ETH_P_IPV6:
 666                                                 if(packet->len < ether_size + ip6_size) {
 667                                                         ifdebug(TRAFFIC) logger(LOG_WARNING, _("Read too short packet"));
 668                                                         return;
 669                                                 }
 670
 671                                                 n = route_ipv6(packet);
 672                                                 break;
 673
 674                                         default:
 675                                                 n = myself;
 676                                                 break;
 677                                 }
 678
 679                                 if(n) {
 680                                         if(n == myself) {
 681                                                 if(overwrite_mac)
 682                                                         memcpy(packet->data, mymac.x, ETH_ALEN);
 683                                                 write_packet(packet);
 684                                         } else
 685                                                 send_packet(n, packet);
 686                                 }
 687                         }
 688                         break;
 689
 690                 case RMODE_SWITCH:
 691                         {
 692                                 subnet_t *subnet;
 693
 694                                 subnet = lookup_subnet_mac((mac_t *)(&packet->data[0]));
 695
 696                                 if(subnet) {
 697                                         if(subnet->owner == myself)
 698                                                 write_packet(packet);
 699                                         else
 700                                                 send_packet(subnet->owner, packet);
 701                                 } else {
 702                                         broadcast_packet(source, packet);
 703                                         write_packet(packet);
 704                                 }
 705                         }
 706                         break;
 707
 708                 case RMODE_HUB:
 709                         broadcast_packet(source, packet);       /* Spread it on */
 710                         write_packet(packet);
 711                         break;
 712         }
 713 }