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 "logger.h"
  49 #include "net.h"
  50 #include "netutl.h"
  51 #include "protocol.h"
  52 #include "process.h"
  53 #include "route.h"
  54 #include "utils.h"
  55 #include "xalloc.h"
  56
  57 int keylifetime = 0;
  58 #ifdef HAVE_LZO
  59 static char lzo_wrkmem[LZO1X_999_MEM_COMPRESS > LZO1X_1_MEM_COMPRESS ? LZO1X_999_MEM_COMPRESS : LZO1X_1_MEM_COMPRESS];
  60 #endif
  61
  62 static void send_udppacket(node_t *, vpn_packet_t *);
  63
  64 unsigned replaywin = 16;
  65
  66 #define MAX_SEQNO 1073741824
  67
  68 // mtuprobes == 1..30: initial discovery, send bursts with 1 second interval
  69 // mtuprobes ==    31: sleep pinginterval seconds
  70 // mtuprobes ==    32: send 1 burst, sleep pingtimeout second
  71 // mtuprobes ==    33: no response from other side, restart PMTU discovery process
  72
  73 static void send_mtu_probe_handler(int fd, short events, void *data) {
  74         node_t *n = data;
  75         vpn_packet_t packet;
  76         int len, i;
  77         int timeout = 1;
  78
  79         n->mtuprobes++;
  80
  81         if(!n->status.reachable || !n->status.validkey) {
  82                 ifdebug(TRAFFIC) logger(LOG_INFO, "Trying to send MTU probe to unreachable or rekeying node %s (%s)", n->name, n->hostname);
  83                 n->mtuprobes = 0;
  84                 return;
  85         }
  86
  87         if(n->mtuprobes > 32) {
  88                 if(!n->minmtu) {
  89                         n->mtuprobes = 31;
  90                         timeout = pinginterval;
  91                         goto end;
  92                 }
  93
  94                 ifdebug(TRAFFIC) logger(LOG_INFO, "%s (%s) did not respond to UDP ping, restarting PMTU discovery", n->name, n->hostname);
  95                 n->mtuprobes = 1;
  96                 n->minmtu = 0;
  97                 n->maxmtu = MTU;
  98         }
  99
 100         if(n->mtuprobes >= 10 && n->mtuprobes < 32 && !n->minmtu) {
 101                 ifdebug(TRAFFIC) logger(LOG_INFO, "No response to MTU probes from %s (%s)", n->name, n->hostname);
 102                 n->mtuprobes = 31;
 103         }
 104
 105         if(n->mtuprobes == 30 || (n->mtuprobes < 30 && n->minmtu >= n->maxmtu)) {
 106                 if(n->minmtu > n->maxmtu)
 107                         n->minmtu = n->maxmtu;
 108                 else
 109                         n->maxmtu = n->minmtu;
 110                 n->mtu = n->minmtu;
 111                 ifdebug(TRAFFIC) logger(LOG_INFO, "Fixing MTU of %s (%s) to %d after %d probes", n->name, n->hostname, n->mtu, n->mtuprobes);
 112                 n->mtuprobes = 31;
 113         }
 114
 115         if(n->mtuprobes == 31) {
 116                 timeout = pinginterval;
 117                 goto end;
 118         } else if(n->mtuprobes == 32) {
 119                 timeout = pingtimeout;
 120         }
 121
 122         for(i = 0; i < 3; i++) {
 123                 if(n->maxmtu <= n->minmtu)
 124                         len = n->maxmtu;
 125                 else
 126                         len = n->minmtu + 1 + rand() % (n->maxmtu - n->minmtu);
 127
 128                 if(len < 64)
 129                         len = 64;
 130
 131                 memset(packet.data, 0, 14);
 132                 randomize(packet.data + 14, len - 14);
 133                 packet.len = len;
 134                 packet.priority = 0;
 135
 136                 ifdebug(TRAFFIC) logger(LOG_INFO, "Sending MTU probe length %d to %s (%s)", len, n->name, n->hostname);
 137
 138                 send_udppacket(n, &packet);
 139         }
 140
 141 end:
 142         event_add(&n->mtuevent, &(struct timeval){timeout, 0});
 143 }
 144
 145 void send_mtu_probe(node_t *n) {
 146         if(!timeout_initialized(&n->mtuevent))
 147                 timeout_set(&n->mtuevent, send_mtu_probe_handler, n);
 148         send_mtu_probe_handler(0, 0, n);
 149 }
 150
 151 static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
 152         ifdebug(TRAFFIC) logger(LOG_INFO, "Got MTU probe length %d from %s (%s)", packet->len, n->name, n->hostname);
 153
 154         if(!packet->data[0]) {
 155                 packet->data[0] = 1;
 156                 send_udppacket(n, packet);
 157         } else {
 158                 if(n->mtuprobes > 30) {
 159                         if(n->minmtu)
 160                                 n->mtuprobes = 30;
 161                         else
 162                                 n->mtuprobes = 1;
 163                 }
 164
 165                 if(len > n->maxmtu)
 166                         len = n->maxmtu;
 167                 if(n->minmtu < len)
 168                         n->minmtu = len;
 169         }
 170 }
 171
 172 static length_t compress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level) {
 173         if(level == 0) {
 174                 memcpy(dest, source, len);
 175                 return len;
 176         } else if(level == 10) {
 177 #ifdef HAVE_LZO
 178                 lzo_uint lzolen = MAXSIZE;
 179                 lzo1x_1_compress(source, len, dest, &lzolen, lzo_wrkmem);
 180                 return lzolen;
 181 #else
 182                 return -1;
 183 #endif
 184         } else if(level < 10) {
 185 #ifdef HAVE_ZLIB
 186                 unsigned long destlen = MAXSIZE;
 187                 if(compress2(dest, &destlen, source, len, level) == Z_OK)
 188                         return destlen;
 189                 else
 190 #endif
 191                         return -1;
 192         } else {
 193 #ifdef HAVE_LZO
 194                 lzo_uint lzolen = MAXSIZE;
 195                 lzo1x_999_compress(source, len, dest, &lzolen, lzo_wrkmem);
 196                 return lzolen;
 197 #else
 198                 return -1;
 199 #endif
 200         }
 201
 202         return -1;
 203 }
 204
 205 static length_t uncompress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level) {
 206         if(level == 0) {
 207                 memcpy(dest, source, len);
 208                 return len;
 209         } else if(level > 9) {
 210 #ifdef HAVE_LZO
 211                 lzo_uint lzolen = MAXSIZE;
 212                 if(lzo1x_decompress_safe(source, len, dest, &lzolen, NULL) == LZO_E_OK)
 213                         return lzolen;
 214                 else
 215 #endif
 216                         return -1;
 217         }
 218 #ifdef HAVE_ZLIB
 219         else {
 220                 unsigned long destlen = MAXSIZE;
 221                 if(uncompress(dest, &destlen, source, len) == Z_OK)
 222                         return destlen;
 223                 else
 224                         return -1;
 225         }
 226 #endif
 227
 228         return -1;
 229 }
 230
 231 /* VPN packet I/O */
 232
 233 static void receive_packet(node_t *n, vpn_packet_t *packet) {
 234         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Received packet of %d bytes from %s (%s)",
 235                            packet->len, n->name, n->hostname);
 236
 237         n->in_packets++;
 238         n->in_bytes += packet->len;
 239
 240         route(n, packet);
 241 }
 242
 243 static bool try_mac(node_t *n, const vpn_packet_t *inpkt) {
 244         if(!digest_active(&n->indigest) || inpkt->len < sizeof inpkt->seqno + digest_length(&n->indigest))
 245                 return false;
 246
 247         return digest_verify(&n->indigest, &inpkt->seqno, inpkt->len - n->indigest.maclength, (const char *)&inpkt->seqno + inpkt->len - n->indigest.maclength);
 248 }
 249
 250 static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 251         vpn_packet_t pkt1, pkt2;
 252         vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
 253         int nextpkt = 0;
 254         vpn_packet_t *outpkt = pkt[0];
 255         size_t outlen;
 256
 257         if(!cipher_active(&n->incipher)) {
 258                 ifdebug(TRAFFIC) logger(LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet",
 259                                         n->name, n->hostname);
 260                 return;
 261         }
 262
 263         /* Check packet length */
 264
 265         if(inpkt->len < sizeof inpkt->seqno + digest_length(&n->indigest)) {
 266                 ifdebug(TRAFFIC) logger(LOG_DEBUG, "Got too short packet from %s (%s)",
 267                                         n->name, n->hostname);
 268                 return;
 269         }
 270
 271         /* Check the message authentication code */
 272
 273         if(digest_active(&n->indigest)) {
 274                 inpkt->len -= n->indigest.maclength;
 275                 if(!digest_verify(&n->indigest, &inpkt->seqno, inpkt->len, (const char *)&inpkt->seqno + inpkt->len)) {
 276                         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Got unauthenticated packet from %s (%s)", n->name, n->hostname);
 277                         return;
 278                 }
 279         }
 280         /* Decrypt the packet */
 281
 282         if(cipher_active(&n->incipher)) {
 283                 outpkt = pkt[nextpkt++];
 284                 outlen = MAXSIZE;
 285
 286                 if(!cipher_decrypt(&n->incipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
 287                         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Error decrypting packet from %s (%s)", n->name, n->hostname);
 288                         return;
 289                 }
 290
 291                 outpkt->len = outlen;
 292                 inpkt = outpkt;
 293         }
 294
 295         /* Check the sequence number */
 296
 297         inpkt->len -= sizeof inpkt->seqno;
 298         inpkt->seqno = ntohl(inpkt->seqno);
 299
 300         if(replaywin) {
 301                 if(inpkt->seqno != n->received_seqno + 1) {
 302                         if(inpkt->seqno >= n->received_seqno + replaywin * 8) {
 303                                 if(n->farfuture++ < replaywin >> 2) {
 304                                         logger(LOG_WARNING, "Packet from %s (%s) is %d seqs in the future, dropped (%u)",
 305                                                 n->name, n->hostname, inpkt->seqno - n->received_seqno - 1, n->farfuture);
 306                                         return;
 307                                 }
 308                                 logger(LOG_WARNING, "Lost %d packets from %s (%s)",
 309                                                 inpkt->seqno - n->received_seqno - 1, n->name, n->hostname);
 310                                 memset(n->late, 0, replaywin);
 311                         } else if (inpkt->seqno <= n->received_seqno) {
 312                                 if((n->received_seqno >= replaywin * 8 && inpkt->seqno <= n->received_seqno - replaywin * 8) || !(n->late[(inpkt->seqno / 8) % replaywin] & (1 << inpkt->seqno % 8))) {
 313                                         logger(LOG_WARNING, "Got late or replayed packet from %s (%s), seqno %d, last received %d",
 314                                                 n->name, n->hostname, inpkt->seqno, n->received_seqno);
 315                                         return;
 316                                 }
 317                         } else {
 318                                 for(int i = n->received_seqno + 1; i < inpkt->seqno; i++)
 319                                         n->late[(i / 8) % replaywin] |= 1 << i % 8;
 320                         }
 321                 }
 322
 323                 n->farfuture = 0;
 324                 n->late[(inpkt->seqno / 8) % replaywin] &= ~(1 << inpkt->seqno % 8);
 325         }
 326
 327         if(inpkt->seqno > n->received_seqno)
 328                 n->received_seqno = inpkt->seqno;
 329
 330         if(n->received_seqno > MAX_SEQNO)
 331                 regenerate_key();
 332
 333         /* Decompress the packet */
 334
 335         length_t origlen = inpkt->len;
 336
 337         if(n->incompression) {
 338                 outpkt = pkt[nextpkt++];
 339
 340                 if((outpkt->len = uncompress_packet(outpkt->data, inpkt->data, inpkt->len, n->incompression)) < 0) {
 341                         ifdebug(TRAFFIC) logger(LOG_ERR, "Error while uncompressing packet from %s (%s)",
 342                                                  n->name, n->hostname);
 343                         return;
 344                 }
 345
 346                 inpkt = outpkt;
 347
 348                 origlen -= MTU/64 + 20;
 349         }
 350
 351         inpkt->priority = 0;
 352
 353         if(!inpkt->data[12] && !inpkt->data[13])
 354                 mtu_probe_h(n, inpkt, origlen);
 355         else
 356                 receive_packet(n, inpkt);
 357 }
 358
 359 void receive_tcppacket(connection_t *c, const char *buffer, int len) {
 360         vpn_packet_t outpkt;
 361
 362         outpkt.len = len;
 363         if(c->options & OPTION_TCPONLY)
 364                 outpkt.priority = 0;
 365         else
 366                 outpkt.priority = -1;
 367         memcpy(outpkt.data, buffer, len);
 368
 369         receive_packet(c->node, &outpkt);
 370 }
 371
 372 static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
 373         vpn_packet_t pkt1, pkt2;
 374         vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
 375         vpn_packet_t *inpkt = origpkt;
 376         int nextpkt = 0;
 377         vpn_packet_t *outpkt;
 378         int origlen = origpkt->len;
 379         size_t outlen;
 380 #if defined(SOL_IP) && defined(IP_TOS)
 381         static int priority = 0;
 382         int origpriority = origpkt->priority;
 383 #endif
 384
 385         if(!n->status.reachable) {
 386                 ifdebug(TRAFFIC) logger(LOG_INFO, "Trying to send UDP packet to unreachable node %s (%s)", n->name, n->hostname);
 387                 return;
 388         }
 389
 390         /* Make sure we have a valid key */
 391
 392         if(!n->status.validkey) {
 393                 time_t now = time(NULL);
 394
 395                 ifdebug(TRAFFIC) logger(LOG_INFO,
 396                                    "No valid key known yet for %s (%s), forwarding via TCP",
 397                                    n->name, n->hostname);
 398
 399                 if(n->last_req_key + 10 <= now) {
 400                         send_req_key(n);
 401                         n->last_req_key = now;
 402                 }
 403
 404                 send_tcppacket(n->nexthop->connection, origpkt);
 405
 406                 return;
 407         }
 408
 409         if(n->options & OPTION_PMTU_DISCOVERY && inpkt->len > n->minmtu && (inpkt->data[12] | inpkt->data[13])) {
 410                 ifdebug(TRAFFIC) logger(LOG_INFO,
 411                                 "Packet for %s (%s) larger than minimum MTU, forwarding via %s",
 412                                 n->name, n->hostname, n != n->nexthop ? n->nexthop->name : "TCP");
 413
 414                 if(n != n->nexthop)
 415                         send_packet(n->nexthop, origpkt);
 416                 else
 417                         send_tcppacket(n->nexthop->connection, origpkt);
 418
 419                 return;
 420         }
 421
 422         /* Compress the packet */
 423
 424         if(n->outcompression) {
 425                 outpkt = pkt[nextpkt++];
 426
 427                 if((outpkt->len = compress_packet(outpkt->data, inpkt->data, inpkt->len, n->outcompression)) < 0) {
 428                         ifdebug(TRAFFIC) logger(LOG_ERR, "Error while compressing packet to %s (%s)",
 429                                    n->name, n->hostname);
 430                         return;
 431                 }
 432
 433                 inpkt = outpkt;
 434         }
 435
 436         /* Add sequence number */
 437
 438         inpkt->seqno = htonl(++(n->sent_seqno));
 439         inpkt->len += sizeof inpkt->seqno;
 440
 441         /* Encrypt the packet */
 442
 443         if(cipher_active(&n->outcipher)) {
 444                 outpkt = pkt[nextpkt++];
 445                 outlen = MAXSIZE;
 446
 447                 if(!cipher_encrypt(&n->outcipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
 448                         ifdebug(TRAFFIC) logger(LOG_ERR, "Error while encrypting packet to %s (%s)", n->name, n->hostname);
 449                         goto end;
 450                 }
 451
 452                 outpkt->len = outlen;
 453                 inpkt = outpkt;
 454         }
 455
 456         /* Add the message authentication code */
 457
 458         if(digest_active(&n->outdigest)) {
 459                 digest_create(&n->outdigest, &inpkt->seqno, inpkt->len, (char *)&inpkt->seqno + inpkt->len);
 460                 inpkt->len += digest_length(&n->outdigest);
 461         }
 462
 463         /* Determine which socket we have to use */
 464
 465         if(n->address.sa.sa_family != listen_socket[n->sock].sa.sa.sa_family) {
 466                 for(int sock = 0; sock < listen_sockets; sock++) {
 467                         if(n->address.sa.sa_family == listen_socket[sock].sa.sa.sa_family) {
 468                                 n->sock = sock;
 469                                 break;
 470                         }
 471                 }
 472         }
 473
 474         /* Send the packet */
 475
 476 #if defined(SOL_IP) && defined(IP_TOS)
 477         if(priorityinheritance && origpriority != priority
 478            && listen_socket[n->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[n->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[n->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                 devops.write(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         for(node = edge_weight_tree->head; node; node = node->next) {
 575                 e = node->data;
 576
 577                 if(e->to == myself)
 578                         continue;
 579
 580                 if(sockaddrcmp_noport(from, &e->address)) {
 581                         if(last_hard_try == now)
 582                                 continue;
 583                         hard = true;
 584                 }
 585
 586                 if(!try_mac(e->to, pkt))
 587                         continue;
 588
 589                 n = e->to;
 590                 break;
 591         }
 592
 593         if(hard)
 594                 last_hard_try = now;
 595
 596         return n;
 597 }
 598
 599 void handle_incoming_vpn_data(int sock, short events, void *data) {
 600         vpn_packet_t pkt;
 601         char *hostname;
 602         sockaddr_t from;
 603         socklen_t fromlen = sizeof from;
 604         node_t *n;
 605         int len;
 606
 607         len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
 608
 609         if(len <= 0 || len > MAXSIZE) {
 610                 if(!sockwouldblock(sockerrno))
 611                         logger(LOG_ERR, "Receiving packet failed: %s", sockstrerror(sockerrno));
 612                 return;
 613         }
 614
 615         pkt.len = len;
 616
 617         sockaddrunmap(&from);           /* Some braindead IPv6 implementations do stupid things. */
 618
 619         n = lookup_node_udp(&from);
 620
 621         if(!n) {
 622                 n = try_harder(&from, &pkt);
 623                 if(n)
 624                         update_node_udp(n, &from);
 625                 else ifdebug(PROTOCOL) {
 626                         hostname = sockaddr2hostname(&from);
 627                         logger(LOG_WARNING, "Received UDP packet from unknown source %s", hostname);
 628                         free(hostname);
 629                         return;
 630                 }
 631                 else
 632                         return;
 633         }
 634
 635         n->sock = (intptr_t)data;
 636
 637         receive_udppacket(n, &pkt);
 638 }
 639
 640 void handle_device_data(int sock, short events, void *data) {
 641         vpn_packet_t packet;
 642
 643         packet.priority = 0;
 644
 645         if(devops.read(&packet)) {
 646                 myself->in_packets++;
 647                 myself->in_bytes += packet.len;
 648                 route(myself, &packet);
 649         }
 650 }