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

   1 /*
   2     net_socket.c -- Handle various kinds of sockets.
   3     Copyright (C) 1998-2005 Ivo Timmermans,
   4                   2000-2010 Guus Sliepen <guus@tinc-vpn.org>
   5                   2006      Scott Lamb <slamb@slamb.org>
   6                   2009      Florian Forster <octo@verplant.org>
   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 "avl_tree.h"
  26 #include "conf.h"
  27 #include "connection.h"
  28 #include "event.h"
  29 #include "logger.h"
  30 #include "meta.h"
  31 #include "net.h"
  32 #include "netutl.h"
  33 #include "protocol.h"
  34 #include "utils.h"
  35 #include "xalloc.h"
  36
  37 #include <assert.h>
  38
  39 /* Needed on Mac OS/X */
  40 #ifndef SOL_TCP
  41 #define SOL_TCP IPPROTO_TCP
  42 #endif
  43
  44 int addressfamily = AF_UNSPEC;
  45 int maxtimeout = 900;
  46 int seconds_till_retry = 5;
  47 int udp_rcvbuf = 0;
  48 int udp_sndbuf = 0;
  49
  50 listen_socket_t listen_socket[MAXSOCKETS];
  51 int listen_sockets;
  52 list_t *outgoing_list = NULL;
  53
  54 /* Setup sockets */
  55
  56 static void configure_tcp(connection_t *c) {
  57         int option;
  58
  59 #ifdef O_NONBLOCK
  60         int flags = fcntl(c->socket, F_GETFL);
  61
  62         if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
  63                 logger(LOG_ERR, "fcntl for %s: %s", c->hostname, strerror(errno));
  64         }
  65 #elif defined(WIN32)
  66         unsigned long arg = 1;
  67
  68         if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
  69                 logger(LOG_ERR, "ioctlsocket for %s: %d", c->hostname, sockstrerror(sockerrno));
  70         }
  71 #endif
  72
  73 #if defined(SOL_TCP) && defined(TCP_NODELAY)
  74         option = 1;
  75         setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&option, sizeof(option));
  76 #endif
  77
  78 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
  79         option = IPTOS_LOWDELAY;
  80         setsockopt(c->socket, SOL_IP, IP_TOS, (void *)&option, sizeof(option));
  81 #endif
  82 }
  83
  84 static bool bind_to_interface(int sd) {
  85         char *iface;
  86
  87 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  88         struct ifreq ifr;
  89         int status;
  90 #endif /* defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) */
  91
  92         if(!get_config_string (lookup_config (config_tree, "BindToInterface"), &iface))
  93                 return true;
  94
  95 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  96         memset(&ifr, 0, sizeof(ifr));
  97         strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
  98         ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
  99
 100         status = setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr));
 101         if(status) {
 102                 logger(LOG_ERR, "Can't bind to interface %s: %s", iface,
 103                                 strerror(errno));
 104                 return false;
 105         }
 106 #else /* if !defined(SOL_SOCKET) || !defined(SO_BINDTODEVICE) */
 107         logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 108 #endif
 109
 110         return true;
 111 }
 112
 113 static bool bind_to_address(connection_t *c) {
 114         char *node;
 115         struct addrinfo *ai_list;
 116         struct addrinfo *ai_ptr;
 117         struct addrinfo ai_hints;
 118         int status;
 119
 120         assert(c != NULL);
 121         assert(c->socket >= 0);
 122
 123         node = NULL;
 124         if(!get_config_string(lookup_config(config_tree, "BindToAddress"),
 125                                 &node))
 126                 return true;
 127
 128         assert(node != NULL);
 129
 130         memset(&ai_hints, 0, sizeof(ai_hints));
 131         ai_hints.ai_family = c->address.sa.sa_family;
 132         /* We're called from `do_outgoing_connection' only. */
 133         ai_hints.ai_socktype = SOCK_STREAM;
 134         ai_hints.ai_protocol = IPPROTO_TCP;
 135
 136         ai_list = NULL;
 137
 138         status = getaddrinfo(node, /* service = */ NULL,
 139                         &ai_hints, &ai_list);
 140         if(status) {
 141                 free(node);
 142                 logger(LOG_WARNING, "Error looking up %s port %s: %s",
 143                                 node, "any", gai_strerror(status));
 144                 return false;
 145         }
 146         assert(ai_list != NULL);
 147
 148         status = -1;
 149         for(ai_ptr = ai_list; ai_ptr != NULL; ai_ptr = ai_ptr->ai_next) {
 150                 status = bind(c->socket,
 151                                 ai_list->ai_addr, ai_list->ai_addrlen);
 152                 if(!status)
 153                         break;
 154         }
 155
 156
 157         if(status) {
 158                 logger(LOG_ERR, "Can't bind to %s/tcp: %s", node, sockstrerror(sockerrno));
 159         } else ifdebug(CONNECTIONS) {
 160                 logger(LOG_DEBUG, "Successfully bound outgoing "
 161                                 "TCP socket to %s", node);
 162         }
 163
 164         free(node);
 165         freeaddrinfo(ai_list);
 166
 167         return status ? false : true;
 168 }
 169
 170 int setup_listen_socket(const sockaddr_t *sa) {
 171         int nfd;
 172         char *addrstr;
 173         int option;
 174         char *iface;
 175
 176         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 177
 178         if(nfd < 0) {
 179                 ifdebug(STATUS) logger(LOG_ERR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
 180                 return -1;
 181         }
 182
 183         /* Optimize TCP settings */
 184
 185         option = 1;
 186         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
 187
 188 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 189         if(sa->sa.sa_family == AF_INET6)
 190                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 191 #endif
 192
 193         if(get_config_string
 194            (lookup_config(config_tree, "BindToInterface"), &iface)) {
 195 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
 196                 struct ifreq ifr;
 197
 198                 memset(&ifr, 0, sizeof(ifr));
 199                 strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
 200
 201                 if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr))) {
 202                         closesocket(nfd);
 203                         logger(LOG_ERR, "Can't bind to interface %s: %s", iface,
 204                                    strerror(sockerrno));
 205                         return -1;
 206                 }
 207 #else
 208                 logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 209 #endif
 210         }
 211
 212         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 213                 closesocket(nfd);
 214                 addrstr = sockaddr2hostname(sa);
 215                 logger(LOG_ERR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
 216                 free(addrstr);
 217                 return -1;
 218         }
 219
 220         if(listen(nfd, 3)) {
 221                 closesocket(nfd);
 222                 logger(LOG_ERR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
 223                 return -1;
 224         }
 225
 226         return nfd;
 227 }
 228
 229 int setup_vpn_in_socket(const sockaddr_t *sa) {
 230         int nfd;
 231         char *addrstr;
 232         int option;
 233
 234         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 235
 236         if(nfd < 0) {
 237                 logger(LOG_ERR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
 238                 return -1;
 239         }
 240
 241 #ifdef O_NONBLOCK
 242         {
 243                 int flags = fcntl(nfd, F_GETFL);
 244
 245                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
 246                         closesocket(nfd);
 247                         logger(LOG_ERR, "System call `%s' failed: %s", "fcntl",
 248                                    strerror(errno));
 249                         return -1;
 250                 }
 251         }
 252 #elif defined(WIN32)
 253         {
 254                 unsigned long arg = 1;
 255                 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
 256                         closesocket(nfd);
 257                         logger(LOG_ERR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
 258                         return -1;
 259                 }
 260         }
 261 #endif
 262
 263         option = 1;
 264         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
 265
 266         if(udp_rcvbuf && setsockopt(nfd, SOL_SOCKET, SO_RCVBUF, (void *)&udp_rcvbuf, sizeof(udp_rcvbuf)))
 267                 logger(LOG_WARNING, "Can't set UDP SO_RCVBUF to %i: %s", udp_rcvbuf, strerror(errno));
 268
 269         if(udp_sndbuf && setsockopt(nfd, SOL_SOCKET, SO_SNDBUF, (void *)&udp_sndbuf, sizeof(udp_sndbuf)))
 270                 logger(LOG_WARNING, "Can't set UDP SO_SNDBUF to %i: %s", udp_sndbuf, strerror(errno));
 271
 272 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
 273         if(sa->sa.sa_family == AF_INET6)
 274                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 275 #endif
 276
 277 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
 278 #define IP_DONTFRAGMENT IP_DONTFRAG
 279 #endif
 280
 281 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 282         if(myself->options & OPTION_PMTU_DISCOVERY) {
 283                 option = IP_PMTUDISC_DO;
 284                 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
 285         }
 286 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
 287         if(myself->options & OPTION_PMTU_DISCOVERY) {
 288                 option = 1;
 289                 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
 290         }
 291 #else
 292 #warning No way to disable IPv4 fragmentation
 293 #endif
 294
 295 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 296         if(myself->options & OPTION_PMTU_DISCOVERY) {
 297                 option = IPV6_PMTUDISC_DO;
 298                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
 299         }
 300 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
 301         if(myself->options & OPTION_PMTU_DISCOVERY) {
 302                 option = 1;
 303                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
 304         }
 305 #else
 306 #warning No way to disable IPv6 fragmentation
 307 #endif
 308
 309         if (!bind_to_interface(nfd)) {
 310                 closesocket(nfd);
 311                 return -1;
 312         }
 313
 314         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 315                 closesocket(nfd);
 316                 addrstr = sockaddr2hostname(sa);
 317                 logger(LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
 318                 free(addrstr);
 319                 return -1;
 320         }
 321
 322         return nfd;
 323 } /* int setup_vpn_in_socket */
 324
 325 void retry_outgoing(outgoing_t *outgoing) {
 326         outgoing->timeout += 5;
 327
 328         if(outgoing->timeout > maxtimeout)
 329                 outgoing->timeout = maxtimeout;
 330
 331         if(outgoing->event)
 332                 event_del(outgoing->event);
 333         outgoing->event = new_event();
 334         outgoing->event->handler = (event_handler_t) setup_outgoing_connection;
 335         outgoing->event->time = now + outgoing->timeout;
 336         outgoing->event->data = outgoing;
 337         event_add(outgoing->event);
 338
 339         ifdebug(CONNECTIONS) logger(LOG_NOTICE,
 340                            "Trying to re-establish outgoing connection in %d seconds",
 341                            outgoing->timeout);
 342 }
 343
 344 void finish_connecting(connection_t *c) {
 345         ifdebug(CONNECTIONS) logger(LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 346
 347         configure_tcp(c);
 348
 349         c->last_ping_time = now;
 350
 351         send_id(c);
 352 }
 353
 354 void do_outgoing_connection(connection_t *c) {
 355         char *address, *port, *space;
 356         int result;
 357
 358         if(!c->outgoing) {
 359                 logger(LOG_ERR, "do_outgoing_connection() for %s called without c->outgoing", c->name);
 360                 abort();
 361         }
 362
 363 begin:
 364         if(!c->outgoing->ai) {
 365                 if(!c->outgoing->cfg) {
 366                         ifdebug(CONNECTIONS) logger(LOG_ERR, "Could not set up a meta connection to %s",
 367                                            c->name);
 368                         c->status.remove = true;
 369                         retry_outgoing(c->outgoing);
 370                         c->outgoing = NULL;
 371                         return;
 372                 }
 373
 374                 get_config_string(c->outgoing->cfg, &address);
 375
 376                 space = strchr(address, ' ');
 377                 if(space) {
 378                         port = xstrdup(space + 1);
 379                         *space = 0;
 380                 } else {
 381                         if(!get_config_string(lookup_config(c->config_tree, "Port"), &port))
 382                                 port = xstrdup("655");
 383                 }
 384
 385                 c->outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 386                 free(address);
 387                 free(port);
 388
 389                 c->outgoing->aip = c->outgoing->ai;
 390                 c->outgoing->cfg = lookup_config_next(c->config_tree, c->outgoing->cfg);
 391         }
 392
 393         if(!c->outgoing->aip) {
 394                 if(c->outgoing->ai)
 395                         freeaddrinfo(c->outgoing->ai);
 396                 c->outgoing->ai = NULL;
 397                 goto begin;
 398         }
 399
 400         memcpy(&c->address, c->outgoing->aip->ai_addr, c->outgoing->aip->ai_addrlen);
 401         c->outgoing->aip = c->outgoing->aip->ai_next;
 402
 403         if(c->hostname)
 404                 free(c->hostname);
 405
 406         c->hostname = sockaddr2hostname(&c->address);
 407
 408         ifdebug(CONNECTIONS) logger(LOG_INFO, "Trying to connect to %s (%s)", c->name,
 409                            c->hostname);
 410
 411         c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 412
 413         if(c->socket == -1) {
 414                 ifdebug(CONNECTIONS) logger(LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
 415                 goto begin;
 416         }
 417
 418 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 419         int option = 1;
 420         if(c->address.sa.sa_family == AF_INET6)
 421                 setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 422 #endif
 423
 424         bind_to_interface(c->socket);
 425         bind_to_address(c);
 426
 427         /* Optimize TCP settings */
 428
 429         configure_tcp(c);
 430
 431         /* Connect */
 432
 433         result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 434
 435         if(result == -1) {
 436                 if(sockinprogress(sockerrno)) {
 437                         c->status.connecting = true;
 438                         return;
 439                 }
 440
 441                 closesocket(c->socket);
 442
 443                 ifdebug(CONNECTIONS) logger(LOG_ERR, "%s: %s", c->hostname, sockstrerror(sockerrno));
 444
 445                 goto begin;
 446         }
 447
 448         finish_connecting(c);
 449
 450         return;
 451 }
 452
 453 void setup_outgoing_connection(outgoing_t *outgoing) {
 454         connection_t *c;
 455         node_t *n;
 456
 457         outgoing->event = NULL;
 458
 459         n = lookup_node(outgoing->name);
 460
 461         if(n)
 462                 if(n->connection) {
 463                         ifdebug(CONNECTIONS) logger(LOG_INFO, "Already connected to %s", outgoing->name);
 464
 465                         n->connection->outgoing = outgoing;
 466                         return;
 467                 }
 468
 469         c = new_connection();
 470         c->name = xstrdup(outgoing->name);
 471         c->outcipher = myself->connection->outcipher;
 472         c->outdigest = myself->connection->outdigest;
 473         c->outmaclength = myself->connection->outmaclength;
 474         c->outcompression = myself->connection->outcompression;
 475
 476         init_configuration(&c->config_tree);
 477         read_connection_config(c);
 478
 479         outgoing->cfg = lookup_config(c->config_tree, "Address");
 480
 481         if(!outgoing->cfg) {
 482                 logger(LOG_ERR, "No address specified for %s", c->name);
 483                 free_connection(c);
 484                 return;
 485         }
 486
 487         c->outgoing = outgoing;
 488         c->last_ping_time = now;
 489
 490         connection_add(c);
 491
 492         do_outgoing_connection(c);
 493 }
 494
 495 /*
 496   accept a new tcp connect and create a
 497   new connection
 498 */
 499 bool handle_new_meta_connection(int sock) {
 500         connection_t *c;
 501         sockaddr_t sa;
 502         int fd;
 503         socklen_t len = sizeof(sa);
 504
 505         fd = accept(sock, &sa.sa, &len);
 506
 507         if(fd < 0) {
 508                 logger(LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 509                 return false;
 510         }
 511
 512         sockaddrunmap(&sa);
 513
 514         c = new_connection();
 515         c->name = xstrdup("<unknown>");
 516         c->outcipher = myself->connection->outcipher;
 517         c->outdigest = myself->connection->outdigest;
 518         c->outmaclength = myself->connection->outmaclength;
 519         c->outcompression = myself->connection->outcompression;
 520
 521         c->address = sa;
 522         c->hostname = sockaddr2hostname(&sa);
 523         c->socket = fd;
 524         c->last_ping_time = now;
 525
 526         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection from %s", c->hostname);
 527
 528         configure_tcp(c);
 529
 530         connection_add(c);
 531
 532         c->allow_request = ID;
 533         send_id(c);
 534
 535         return true;
 536 }
 537
 538 static void free_outgoing(outgoing_t *outgoing) {
 539         if(outgoing->ai)
 540                 freeaddrinfo(outgoing->ai);
 541
 542         if(outgoing->name)
 543                 free(outgoing->name);
 544
 545         free(outgoing);
 546 }
 547
 548 void try_outgoing_connections(void) {
 549         static config_t *cfg = NULL;
 550         char *name;
 551         outgoing_t *outgoing;
 552
 553         outgoing_list = list_alloc((list_action_t)free_outgoing);
 554
 555         for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 556                 get_config_string(cfg, &name);
 557
 558                 if(!check_id(name)) {
 559                         logger(LOG_ERR,
 560                                    "Invalid name for outgoing connection in %s line %d",
 561                                    cfg->file, cfg->line);
 562                         free(name);
 563                         continue;
 564                 }
 565
 566                 outgoing = xmalloc_and_zero(sizeof(*outgoing));
 567                 outgoing->name = name;
 568                 list_insert_tail(outgoing_list, outgoing);
 569                 setup_outgoing_connection(outgoing);
 570         }
 571 }