tinc-vpn.org Git - tinc/blob - src/net_packet.c

   1 /*
   2     net_packet.c -- Handles in- and outgoing VPN packets
   3     Copyright (C) 1998-2005 Ivo Timmermans,
   4                   2000-2011 Guus Sliepen <guus@tinc-vpn.org>
   5                   2010      Timothy Redaelli <timothy@redaelli.eu>
   6                   2010      Brandon Black <blblack@gmail.com>
   7
   8     This program is free software; you can redistribute it and/or modify
   9     it under the terms of the GNU General Public License as published by
  10     the Free Software Foundation; either version 2 of the License, or
  11     (at your option) any later version.
  12
  13     This program is distributed in the hope that it will be useful,
  14     but WITHOUT ANY WARRANTY; without even the implied warranty of
  15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16     GNU General Public License for more details.
  17
  18     You should have received a copy of the GNU General Public License along
  19     with this program; if not, write to the Free Software Foundation, Inc.,
  20     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21 */
  22
  23 #include "system.h"
  24
  25 #include <openssl/rand.h>
  26 #include <openssl/err.h>
  27 #include <openssl/evp.h>
  28 #include <openssl/pem.h>
  29 #include <openssl/hmac.h>
  30
  31 #ifdef HAVE_ZLIB
  32 #include <zlib.h>
  33 #endif
  34
  35 #ifdef HAVE_LZO
  36 #include LZO1X_H
  37 #endif
  38
  39 #include "splay_tree.h"
  40 #include "cipher.h"
  41 #include "conf.h"
  42 #include "connection.h"
  43 #include "crypto.h"
  44 #include "digest.h"
  45 #include "device.h"
  46 #include "ethernet.h"
  47 #include "graph.h"
  48 #include "list.h"
  49 #include "logger.h"
  50 #include "net.h"
  51 #include "netutl.h"
  52 #include "protocol.h"
  53 #include "process.h"
  54 #include "route.h"
  55 #include "utils.h"
  56 #include "xalloc.h"
  57
  58 int keylifetime = 0;
  59 int keyexpires = 0;
  60 #ifdef HAVE_LZO
  61 static char lzo_wrkmem[LZO1X_999_MEM_COMPRESS > LZO1X_1_MEM_COMPRESS ? LZO1X_999_MEM_COMPRESS : LZO1X_1_MEM_COMPRESS];
  62 #endif
  63
  64 static void send_udppacket(node_t *, vpn_packet_t *);
  65
  66 unsigned replaywin = 16;
  67
  68 #define MAX_SEQNO 1073741824
  69
  70 // mtuprobes == 1..30: initial discovery, send bursts with 1 second interval
  71 // mtuprobes ==    31: sleep pinginterval seconds
  72 // mtuprobes ==    32: send 1 burst, sleep pingtimeout second
  73 // mtuprobes ==    33: no response from other side, restart PMTU discovery process
  74
  75 static void send_mtu_probe_handler(int fd, short events, void *data) {
  76         node_t *n = data;
  77         vpn_packet_t packet;
  78         int len, i;
  79         int timeout = 1;
  80
  81         n->mtuprobes++;
  82
  83         if(!n->status.reachable || !n->status.validkey) {
  84                 ifdebug(TRAFFIC) logger(LOG_INFO, "Trying to send MTU probe to unreachable or rekeying node %s (%s)", n->name, n->hostname);
  85                 n->mtuprobes = 0;
  86                 return;
  87         }
  88
  89         if(n->mtuprobes > 32) {
  90                 if(!n->minmtu) {
  91                         n->mtuprobes = 31;
  92                         timeout = pinginterval;
  93                         goto end;
  94                 }
  95
  96                 ifdebug(TRAFFIC) logger(LOG_INFO, "%s (%s) did not respond to UDP ping, restarting PMTU discovery", n->name, n->hostname);
  97                 n->mtuprobes = 1;
  98                 n->minmtu = 0;
  99                 n->maxmtu = MTU;
 100         }
 101
 102         if(n->mtuprobes >= 10 && n->mtuprobes < 32 && !n->minmtu) {
 103                 ifdebug(TRAFFIC) logger(LOG_INFO, "No response to MTU probes from %s (%s)", n->name, n->hostname);
 104                 n->mtuprobes = 31;
 105         }
 106
 107         if(n->mtuprobes == 30 || (n->mtuprobes < 30 && n->minmtu >= n->maxmtu)) {
 108                 if(n->minmtu > n->maxmtu)
 109                         n->minmtu = n->maxmtu;
 110                 else
 111                         n->maxmtu = n->minmtu;
 112                 n->mtu = n->minmtu;
 113                 ifdebug(TRAFFIC) logger(LOG_INFO, "Fixing MTU of %s (%s) to %d after %d probes", n->name, n->hostname, n->mtu, n->mtuprobes);
 114                 n->mtuprobes = 31;
 115         }
 116
 117         if(n->mtuprobes == 31) {
 118                 timeout = pinginterval;
 119                 goto end;
 120         } else if(n->mtuprobes == 32) {
 121                 timeout = pingtimeout;
 122         }
 123
 124         for(i = 0; i < 3; i++) {
 125                 if(n->maxmtu <= n->minmtu)
 126                         len = n->maxmtu;
 127                 else
 128                         len = n->minmtu + 1 + rand() % (n->maxmtu - n->minmtu);
 129
 130                 if(len < 64)
 131                         len = 64;
 132
 133                 memset(packet.data, 0, 14);
 134                 randomize(packet.data + 14, len - 14);
 135                 packet.len = len;
 136                 packet.priority = 0;
 137
 138                 ifdebug(TRAFFIC) logger(LOG_INFO, "Sending MTU probe length %d to %s (%s)", len, n->name, n->hostname);
 139
 140                 send_udppacket(n, &packet);
 141         }
 142
 143 end:
 144         event_add(&n->mtuevent, &(struct timeval){timeout, 0});
 145 }
 146
 147 void send_mtu_probe(node_t *n) {
 148         if(!timeout_initialized(&n->mtuevent))
 149                 timeout_set(&n->mtuevent, send_mtu_probe_handler, n);
 150         send_mtu_probe_handler(0, 0, n);
 151 }
 152
 153 void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
 154         ifdebug(TRAFFIC) logger(LOG_INFO, "Got MTU probe length %d from %s (%s)", packet->len, n->name, n->hostname);
 155
 156         if(!packet->data[0]) {
 157                 packet->data[0] = 1;
 158                 send_udppacket(n, packet);
 159         } else {
 160                 if(n->mtuprobes > 30) {
 161                         if(n->minmtu)
 162                                 n->mtuprobes = 30;
 163                         else
 164                                 n->mtuprobes = 1;
 165                 }
 166
 167                 if(len > n->maxmtu)
 168                         len = n->maxmtu;
 169                 if(n->minmtu < len)
 170                         n->minmtu = len;
 171         }
 172 }
 173
 174 static length_t compress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level) {
 175         if(level == 0) {
 176                 memcpy(dest, source, len);
 177                 return len;
 178         } else if(level == 10) {
 179 #ifdef HAVE_LZO
 180                 lzo_uint lzolen = MAXSIZE;
 181                 lzo1x_1_compress(source, len, dest, &lzolen, lzo_wrkmem);
 182                 return lzolen;
 183 #else
 184                 return -1;
 185 #endif
 186         } else if(level < 10) {
 187 #ifdef HAVE_ZLIB
 188                 unsigned long destlen = MAXSIZE;
 189                 if(compress2(dest, &destlen, source, len, level) == Z_OK)
 190                         return destlen;
 191                 else
 192 #endif
 193                         return -1;
 194         } else {
 195 #ifdef HAVE_LZO
 196                 lzo_uint lzolen = MAXSIZE;
 197                 lzo1x_999_compress(source, len, dest, &lzolen, lzo_wrkmem);
 198                 return lzolen;
 199 #else
 200                 return -1;
 201 #endif
 202         }
 203
 204         return -1;
 205 }
 206
 207 static length_t uncompress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level) {
 208         if(level == 0) {
 209                 memcpy(dest, source, len);
 210                 return len;
 211         } else if(level > 9) {
 212 #ifdef HAVE_LZO
 213                 lzo_uint lzolen = MAXSIZE;
 214                 if(lzo1x_decompress_safe(source, len, dest, &lzolen, NULL) == LZO_E_OK)
 215                         return lzolen;
 216                 else
 217 #endif
 218                         return -1;
 219         }
 220 #ifdef HAVE_ZLIB
 221         else {
 222                 unsigned long destlen = MAXSIZE;
 223                 if(uncompress(dest, &destlen, source, len) == Z_OK)
 224                         return destlen;
 225                 else
 226                         return -1;
 227         }
 228 #endif
 229
 230         return -1;
 231 }
 232
 233 /* VPN packet I/O */
 234
 235 static void receive_packet(node_t *n, vpn_packet_t *packet) {
 236         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Received packet of %d bytes from %s (%s)",
 237                            packet->len, n->name, n->hostname);
 238
 239         n->in_packets++;
 240         n->in_bytes += packet->len;
 241
 242         route(n, packet);
 243 }
 244
 245 static bool try_mac(node_t *n, const vpn_packet_t *inpkt) {
 246         if(!digest_active(&n->indigest) || inpkt->len < sizeof inpkt->seqno + digest_length(&n->indigest))
 247                 return false;
 248
 249         return digest_verify(&n->indigest, &inpkt->seqno, inpkt->len - n->indigest.maclength, (const char *)&inpkt->seqno + inpkt->len - n->indigest.maclength);
 250 }
 251
 252 static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 253         vpn_packet_t pkt1, pkt2;
 254         vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
 255         int nextpkt = 0;
 256         vpn_packet_t *outpkt = pkt[0];
 257         size_t outlen;
 258         int i;
 259
 260         if(!cipher_active(&n->incipher)) {
 261                 ifdebug(TRAFFIC) logger(LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet",
 262                                         n->name, n->hostname);
 263                 return;
 264         }
 265
 266         /* Check packet length */
 267
 268         if(inpkt->len < sizeof inpkt->seqno + digest_length(&n->indigest)) {
 269                 ifdebug(TRAFFIC) logger(LOG_DEBUG, "Got too short packet from %s (%s)",
 270                                         n->name, n->hostname);
 271                 return;
 272         }
 273
 274         /* Check the message authentication code */
 275
 276         if(digest_active(&n->indigest)) {
 277                 inpkt->len -= n->indigest.maclength;
 278                 if(!digest_verify(&n->indigest, &inpkt->seqno, inpkt->len, (const char *)&inpkt->seqno + inpkt->len)) {
 279                         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Got unauthenticated packet from %s (%s)", n->name, n->hostname);
 280                         return;
 281                 }
 282         }
 283         /* Decrypt the packet */
 284
 285         if(cipher_active(&n->incipher)) {
 286                 outpkt = pkt[nextpkt++];
 287                 outlen = MAXSIZE;
 288
 289                 if(!cipher_decrypt(&n->incipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
 290                         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Error decrypting packet from %s (%s)", n->name, n->hostname);
 291                         return;
 292                 }
 293
 294                 outpkt->len = outlen;
 295                 inpkt = outpkt;
 296         }
 297
 298         /* Check the sequence number */
 299
 300         inpkt->len -= sizeof inpkt->seqno;
 301         inpkt->seqno = ntohl(inpkt->seqno);
 302
 303         if(replaywin) {
 304                 if(inpkt->seqno != n->received_seqno + 1) {
 305                         if(inpkt->seqno >= n->received_seqno + replaywin * 8) {
 306                                 if(n->farfuture++ < replaywin >> 2) {
 307                                         logger(LOG_WARNING, "Packet from %s (%s) is %d seqs in the future, dropped (%u)",
 308                                                 n->name, n->hostname, inpkt->seqno - n->received_seqno - 1, n->farfuture);
 309                                         return;
 310                                 }
 311                                 logger(LOG_WARNING, "Lost %d packets from %s (%s)",
 312                                                 inpkt->seqno - n->received_seqno - 1, n->name, n->hostname);
 313                                 memset(n->late, 0, replaywin);
 314                         } else if (inpkt->seqno <= n->received_seqno) {
 315                                 if((n->received_seqno >= replaywin * 8 && inpkt->seqno <= n->received_seqno - replaywin * 8) || !(n->late[(inpkt->seqno / 8) % replaywin] & (1 << inpkt->seqno % 8))) {
 316                                         logger(LOG_WARNING, "Got late or replayed packet from %s (%s), seqno %d, last received %d",
 317                                                 n->name, n->hostname, inpkt->seqno, n->received_seqno);
 318                                         return;
 319                                 }
 320                         } else {
 321                                 for(i = n->received_seqno + 1; i < inpkt->seqno; i++)
 322                                         n->late[(i / 8) % replaywin] |= 1 << i % 8;
 323                         }
 324                 }
 325
 326                 n->farfuture = 0;
 327                 n->late[(inpkt->seqno / 8) % replaywin] &= ~(1 << inpkt->seqno % 8);
 328         }
 329
 330         if(inpkt->seqno > n->received_seqno)
 331                 n->received_seqno = inpkt->seqno;
 332
 333         if(n->received_seqno > MAX_SEQNO)
 334                 regenerate_key();
 335
 336         /* Decompress the packet */
 337
 338         length_t origlen = inpkt->len;
 339
 340         if(n->incompression) {
 341                 outpkt = pkt[nextpkt++];
 342
 343                 if((outpkt->len = uncompress_packet(outpkt->data, inpkt->data, inpkt->len, n->incompression)) < 0) {
 344                         ifdebug(TRAFFIC) logger(LOG_ERR, "Error while uncompressing packet from %s (%s)",
 345                                                  n->name, n->hostname);
 346                         return;
 347                 }
 348
 349                 inpkt = outpkt;
 350
 351                 origlen -= MTU/64 + 20;
 352         }
 353
 354         inpkt->priority = 0;
 355
 356         if(!inpkt->data[12] && !inpkt->data[13])
 357                 mtu_probe_h(n, inpkt, origlen);
 358         else
 359                 receive_packet(n, inpkt);
 360 }
 361
 362 void receive_tcppacket(connection_t *c, char *buffer, int len) {
 363         vpn_packet_t outpkt;
 364
 365         outpkt.len = len;
 366         if(c->options & OPTION_TCPONLY)
 367                 outpkt.priority = 0;
 368         else
 369                 outpkt.priority = -1;
 370         memcpy(outpkt.data, buffer, len);
 371
 372         receive_packet(c->node, &outpkt);
 373 }
 374
 375 static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
 376         vpn_packet_t pkt1, pkt2;
 377         vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
 378         vpn_packet_t *inpkt = origpkt;
 379         int nextpkt = 0;
 380         vpn_packet_t *outpkt;
 381         int origlen;
 382         size_t outlen;
 383 #if defined(SOL_IP) && defined(IP_TOS)
 384         static int priority = 0;
 385 #endif
 386         int origpriority;
 387         int sock;
 388
 389         if(!n->status.reachable) {
 390                 ifdebug(TRAFFIC) logger(LOG_INFO, "Trying to send UDP packet to unreachable node %s (%s)", n->name, n->hostname);
 391                 return;
 392         }
 393
 394         /* Make sure we have a valid key */
 395
 396         if(!n->status.validkey) {
 397                 time_t now = time(NULL);
 398
 399                 ifdebug(TRAFFIC) logger(LOG_INFO,
 400                                    "No valid key known yet for %s (%s), forwarding via TCP",
 401                                    n->name, n->hostname);
 402
 403                 if(n->last_req_key + 10 < now) {
 404                         send_req_key(n);
 405                         n->last_req_key = now;
 406                 }
 407
 408                 send_tcppacket(n->nexthop->connection, origpkt);
 409
 410                 return;
 411         }
 412
 413         if(n->options & OPTION_PMTU_DISCOVERY && inpkt->len > n->minmtu && (inpkt->data[12] | inpkt->data[13])) {
 414                 ifdebug(TRAFFIC) logger(LOG_INFO,
 415                                 "Packet for %s (%s) larger than minimum MTU, forwarding via %s",
 416                                 n->name, n->hostname, n != n->nexthop ? n->nexthop->name : "TCP");
 417
 418                 if(n != n->nexthop)
 419                         send_packet(n->nexthop, origpkt);
 420                 else
 421                         send_tcppacket(n->nexthop->connection, origpkt);
 422
 423                 return;
 424         }
 425
 426         origlen = inpkt->len;
 427         origpriority = inpkt->priority;
 428
 429         /* Compress the packet */
 430
 431         if(n->outcompression) {
 432                 outpkt = pkt[nextpkt++];
 433
 434                 if((outpkt->len = compress_packet(outpkt->data, inpkt->data, inpkt->len, n->outcompression)) < 0) {
 435                         ifdebug(TRAFFIC) logger(LOG_ERR, "Error while compressing packet to %s (%s)",
 436                                    n->name, n->hostname);
 437                         return;
 438                 }
 439
 440                 inpkt = outpkt;
 441         }
 442
 443         /* Add sequence number */
 444
 445         inpkt->seqno = htonl(++(n->sent_seqno));
 446         inpkt->len += sizeof inpkt->seqno;
 447
 448         /* Encrypt the packet */
 449
 450         if(cipher_active(&n->outcipher)) {
 451                 outpkt = pkt[nextpkt++];
 452                 outlen = MAXSIZE;
 453
 454                 if(!cipher_encrypt(&n->outcipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
 455                         ifdebug(TRAFFIC) logger(LOG_ERR, "Error while encrypting packet to %s (%s)", n->name, n->hostname);
 456                         goto end;
 457                 }
 458
 459                 outpkt->len = outlen;
 460                 inpkt = outpkt;
 461         }
 462
 463         /* Add the message authentication code */
 464
 465         if(digest_active(&n->outdigest)) {
 466                 digest_create(&n->outdigest, &inpkt->seqno, inpkt->len, (char *)&inpkt->seqno + inpkt->len);
 467                 inpkt->len += digest_length(&n->outdigest);
 468         }
 469
 470         /* Determine which socket we have to use */
 471
 472         for(sock = 0; sock < listen_sockets; sock++)
 473                 if(n->address.sa.sa_family == listen_socket[sock].sa.sa.sa_family)
 474                         break;
 475
 476         if(sock >= listen_sockets)
 477                 sock = 0;                               /* If none is available, just use the first and hope for the best. */
 478
 479         /* Send the packet */
 480
 481 #if defined(SOL_IP) && defined(IP_TOS)
 482         if(priorityinheritance && origpriority != priority
 483            && listen_socket[sock].sa.sa.sa_family == AF_INET) {
 484                 priority = origpriority;
 485                 ifdebug(TRAFFIC) logger(LOG_DEBUG, "Setting outgoing packet priority to %d", priority);
 486                 if(setsockopt(listen_socket[sock].udp, SOL_IP, IP_TOS, &priority, sizeof priority))     /* SO_PRIORITY doesn't seem to work */
 487                         logger(LOG_ERR, "System call `%s' failed: %s", "setsockopt", strerror(errno));
 488         }
 489 #endif
 490
 491         if(sendto(listen_socket[sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, &(n->address.sa), SALEN(n->address.sa)) < 0 && !sockwouldblock(sockerrno)) {
 492                 if(sockmsgsize(sockerrno)) {
 493                         if(n->maxmtu >= origlen)
 494                                 n->maxmtu = origlen - 1;
 495                         if(n->mtu >= origlen)
 496                                 n->mtu = origlen - 1;
 497                 } else
 498                         logger(LOG_ERR, "Error sending packet to %s (%s): %s", n->name, n->hostname, sockstrerror(sockerrno));
 499         }
 500
 501 end:
 502         origpkt->len = origlen;
 503 }
 504
 505 /*
 506   send a packet to the given vpn ip.
 507 */
 508 void send_packet(node_t *n, vpn_packet_t *packet) {
 509         node_t *via;
 510
 511         if(n == myself) {
 512                 if(overwrite_mac)
 513                          memcpy(packet->data, mymac.x, ETH_ALEN);
 514                 n->out_packets++;
 515                 n->out_bytes += packet->len;
 516                 write_packet(packet);
 517                 return;
 518         }
 519
 520         ifdebug(TRAFFIC) logger(LOG_ERR, "Sending packet of %d bytes to %s (%s)",
 521                            packet->len, n->name, n->hostname);
 522
 523         if(!n->status.reachable) {
 524                 ifdebug(TRAFFIC) logger(LOG_INFO, "Node %s (%s) is not reachable",
 525                                    n->name, n->hostname);
 526                 return;
 527         }
 528
 529         n->out_packets++;
 530         n->out_bytes += packet->len;
 531
 532         via = (packet->priority == -1 || n->via == myself) ? n->nexthop : n->via;
 533
 534         if(via != n)
 535                 ifdebug(TRAFFIC) logger(LOG_INFO, "Sending packet to %s via %s (%s)",
 536                            n->name, via->name, n->via->hostname);
 537
 538         if(packet->priority == -1 || ((myself->options | via->options) & OPTION_TCPONLY)) {
 539                 if(!send_tcppacket(via->connection, packet))
 540                         terminate_connection(via->connection, true);
 541         } else
 542                 send_udppacket(via, packet);
 543 }
 544
 545 /* Broadcast a packet using the minimum spanning tree */
 546
 547 void broadcast_packet(const node_t *from, vpn_packet_t *packet) {
 548         splay_node_t *node;
 549         connection_t *c;
 550
 551         ifdebug(TRAFFIC) logger(LOG_INFO, "Broadcasting packet of %d bytes from %s (%s)",
 552                            packet->len, from->name, from->hostname);
 553
 554         if(from != myself) {
 555                 send_packet(myself, packet);
 556
 557                 // In TunnelServer mode, do not forward broadcast packets.
 558                 // The MST might not be valid and create loops.
 559                 if(tunnelserver)
 560                         return;
 561         }
 562
 563         for(node = connection_tree->head; node; node = node->next) {
 564                 c = node->data;
 565
 566                 if(c->status.active && c->status.mst && c != from->nexthop->connection)
 567                         send_packet(c->node, packet);
 568         }
 569 }
 570
 571 static node_t *try_harder(const sockaddr_t *from, const vpn_packet_t *pkt) {
 572         splay_node_t *node;
 573         edge_t *e;
 574         node_t *n = NULL;
 575         bool hard = false;
 576         static time_t last_hard_try = 0;
 577         time_t now = time(NULL);
 578
 579         if(last_hard_try == now)
 580                 return NULL;
 581         else
 582                 last_hard_try = now;
 583
 584         for(node = edge_weight_tree->head; node; node = node->next) {
 585                 e = node->data;
 586
 587                 if(e->to == myself)
 588                         continue;
 589
 590                 if(sockaddrcmp_noport(from, &e->address)) {
 591                         if(last_hard_try == now)
 592                                 continue;
 593                         hard = true;
 594                 }
 595
 596                 if(!try_mac(e->to, pkt))
 597                         continue;
 598
 599                 n = e->to;
 600                 break;
 601         }
 602
 603         if(hard)
 604                 last_hard_try = now;
 605
 606         return n;
 607 }
 608
 609 void handle_incoming_vpn_data(int sock, short events, void *data) {
 610         vpn_packet_t pkt;
 611         char *hostname;
 612         sockaddr_t from;
 613         socklen_t fromlen = sizeof from;
 614         node_t *n;
 615         int len;
 616
 617         len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
 618
 619         if(len <= 0 || len > MAXSIZE) {
 620                 if(!sockwouldblock(sockerrno))
 621                         logger(LOG_ERR, "Receiving packet failed: %s", sockstrerror(sockerrno));
 622                 return;
 623         }
 624
 625         pkt.len = len;
 626
 627         sockaddrunmap(&from);           /* Some braindead IPv6 implementations do stupid things. */
 628
 629         n = lookup_node_udp(&from);
 630
 631         if(!n) {
 632                 n = try_harder(&from, &pkt);
 633                 if(n)
 634                         update_node_udp(n, &from);
 635                 else ifdebug(PROTOCOL) {
 636                         hostname = sockaddr2hostname(&from);
 637                         logger(LOG_WARNING, "Received UDP packet from unknown source %s", hostname);
 638                         free(hostname);
 639                         return;
 640                 }
 641                 else
 642                         return;
 643         }
 644
 645         receive_udppacket(n, &pkt);
 646 }
 647
 648 void handle_device_data(int sock, short events, void *data) {
 649         vpn_packet_t packet;
 650
 651         if(read_packet(&packet)) {
 652                 myself->in_packets++;
 653                 myself->in_bytes += packet.len;
 654                 route(myself, &packet);
 655         }
 656 }