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