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 "splay_tree.h"
  26 #include "conf.h"
  27 #include "connection.h"
  28 #include "logger.h"
  29 #include "meta.h"
  30 #include "net.h"
  31 #include "netutl.h"
  32 #include "protocol.h"
  33 #include "utils.h"
  34 #include "xalloc.h"
  35
  36 #include <assert.h>
  37
  38 /* Needed on Mac OS/X */
  39 #ifndef SOL_TCP
  40 #define SOL_TCP IPPROTO_TCP
  41 #endif
  42
  43 int addressfamily = AF_UNSPEC;
  44 int maxtimeout = 900;
  45 int seconds_till_retry = 5;
  46
  47 listen_socket_t listen_socket[MAXSOCKETS];
  48 int listen_sockets;
  49 list_t *outgoing_list = NULL;
  50
  51 /* Setup sockets */
  52
  53 static void configure_tcp(connection_t *c) {
  54         int option;
  55
  56 #ifdef O_NONBLOCK
  57         int flags = fcntl(c->socket, F_GETFL);
  58
  59         if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
  60                 logger(LOG_ERR, "fcntl for %s: %s", c->hostname, strerror(errno));
  61         }
  62 #elif defined(WIN32)
  63         unsigned long arg = 1;
  64
  65         if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
  66                 logger(LOG_ERR, "ioctlsocket for %s: %d", c->hostname, sockstrerror(sockerrno));
  67         }
  68 #endif
  69
  70 #if defined(SOL_TCP) && defined(TCP_NODELAY)
  71         option = 1;
  72         setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&option, sizeof option);
  73 #endif
  74
  75 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
  76         option = IPTOS_LOWDELAY;
  77         setsockopt(c->socket, SOL_IP, IP_TOS, (void *)&option, sizeof option);
  78 #endif
  79 }
  80
  81 static bool bind_to_interface(int sd) {
  82         char *iface;
  83
  84 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  85         struct ifreq ifr;
  86         int status;
  87 #endif /* defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) */
  88
  89         if(!get_config_string (lookup_config (config_tree, "BindToInterface"), &iface))
  90                 return true;
  91
  92 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  93         memset(&ifr, 0, sizeof(ifr));
  94         strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
  95         ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
  96
  97         status = setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr));
  98         if(status) {
  99                 logger(LOG_ERR, "Can't bind to interface %s: %s", iface,
 100                                 strerror(errno));
 101                 return false;
 102         }
 103 #else /* if !defined(SOL_SOCKET) || !defined(SO_BINDTODEVICE) */
 104         logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 105 #endif
 106
 107         return true;
 108 }
 109
 110 static bool bind_to_address(connection_t *c) {
 111         char *node;
 112         struct addrinfo *ai_list;
 113         struct addrinfo *ai_ptr;
 114         struct addrinfo ai_hints;
 115         int status;
 116
 117         assert(c != NULL);
 118         assert(c->socket >= 0);
 119
 120         node = NULL;
 121         if(!get_config_string(lookup_config(config_tree, "BindToAddress"),
 122                                 &node))
 123                 return true;
 124
 125         assert(node != NULL);
 126
 127         memset(&ai_hints, 0, sizeof(ai_hints));
 128         ai_hints.ai_family = c->address.sa.sa_family;
 129         /* We're called from `do_outgoing_connection' only. */
 130         ai_hints.ai_socktype = SOCK_STREAM;
 131         ai_hints.ai_protocol = IPPROTO_TCP;
 132
 133         ai_list = NULL;
 134
 135         status = getaddrinfo(node, /* service = */ NULL,
 136                         &ai_hints, &ai_list);
 137         if(status) {
 138                 free(node);
 139                 logger(LOG_WARNING, "Error looking up %s port %s: %s",
 140                                 node, "any", gai_strerror(status));
 141                 return false;
 142         }
 143         assert(ai_list != NULL);
 144
 145         status = -1;
 146         for(ai_ptr = ai_list; ai_ptr != NULL; ai_ptr = ai_ptr->ai_next) {
 147                 status = bind(c->socket,
 148                                 ai_list->ai_addr, ai_list->ai_addrlen);
 149                 if(!status)
 150                         break;
 151         }
 152
 153
 154         if(status) {
 155                 logger(LOG_ERR, "Can't bind to %s/tcp: %s", node, sockstrerror(sockerrno));
 156         } else ifdebug(CONNECTIONS) {
 157                 logger(LOG_DEBUG, "Successfully bound outgoing "
 158                                 "TCP socket to %s", node);
 159         }
 160
 161         free(node);
 162         freeaddrinfo(ai_list);
 163
 164         return status ? false : true;
 165 }
 166
 167 int setup_listen_socket(const sockaddr_t *sa) {
 168         int nfd;
 169         char *addrstr;
 170         int option;
 171         char *iface;
 172
 173         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 174
 175         if(nfd < 0) {
 176                 ifdebug(STATUS) logger(LOG_ERR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
 177                 return -1;
 178         }
 179
 180         /* Optimize TCP settings */
 181
 182         option = 1;
 183         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
 184
 185 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 186         if(sa->sa.sa_family == AF_INET6)
 187                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 188 #endif
 189
 190         if(get_config_string
 191            (lookup_config(config_tree, "BindToInterface"), &iface)) {
 192 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
 193                 struct ifreq ifr;
 194
 195                 memset(&ifr, 0, sizeof ifr);
 196                 strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
 197
 198                 if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof ifr)) {
 199                         closesocket(nfd);
 200                         logger(LOG_ERR, "Can't bind to interface %s: %s", iface,
 201                                    strerror(sockerrno));
 202                         return -1;
 203                 }
 204 #else
 205                 logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 206 #endif
 207         }
 208
 209         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 210                 closesocket(nfd);
 211                 addrstr = sockaddr2hostname(sa);
 212                 logger(LOG_ERR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
 213                 free(addrstr);
 214                 return -1;
 215         }
 216
 217         if(listen(nfd, 3)) {
 218                 closesocket(nfd);
 219                 logger(LOG_ERR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
 220                 return -1;
 221         }
 222
 223         return nfd;
 224 }
 225
 226 int setup_vpn_in_socket(const sockaddr_t *sa) {
 227         int nfd;
 228         char *addrstr;
 229         int option;
 230
 231         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 232
 233         if(nfd < 0) {
 234                 logger(LOG_ERR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
 235                 return -1;
 236         }
 237
 238 #ifdef O_NONBLOCK
 239         {
 240                 int flags = fcntl(nfd, F_GETFL);
 241
 242                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
 243                         closesocket(nfd);
 244                         logger(LOG_ERR, "System call `%s' failed: %s", "fcntl",
 245                                    strerror(errno));
 246                         return -1;
 247                 }
 248         }
 249 #elif defined(WIN32)
 250         {
 251                 unsigned long arg = 1;
 252                 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
 253                         closesocket(nfd);
 254                         logger(LOG_ERR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
 255                         return -1;
 256                 }
 257         }
 258 #endif
 259
 260         option = 1;
 261         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
 262
 263 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
 264         if(sa->sa.sa_family == AF_INET6)
 265                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 266 #endif
 267
 268 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
 269 #define IP_DONTFRAGMENT IP_DONTFRAG
 270 #endif
 271
 272 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 273         if(myself->options & OPTION_PMTU_DISCOVERY) {
 274                 option = IP_PMTUDISC_DO;
 275                 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
 276         }
 277 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
 278         if(myself->options & OPTION_PMTU_DISCOVERY) {
 279                 option = 1;
 280                 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
 281         }
 282 #else
 283 #warning No way to disable IPv4 fragmentation
 284 #endif
 285
 286 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 287         if(myself->options & OPTION_PMTU_DISCOVERY) {
 288                 option = IPV6_PMTUDISC_DO;
 289                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
 290         }
 291 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
 292         if(myself->options & OPTION_PMTU_DISCOVERY) {
 293                 option = 1;
 294                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
 295         }
 296 #else
 297 #warning No way to disable IPv6 fragmentation
 298 #endif
 299
 300         if (!bind_to_interface(nfd)) {
 301                 closesocket(nfd);
 302                 return -1;
 303         }
 304
 305         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 306                 closesocket(nfd);
 307                 addrstr = sockaddr2hostname(sa);
 308                 logger(LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
 309                 free(addrstr);
 310                 return -1;
 311         }
 312
 313         return nfd;
 314 } /* int setup_vpn_in_socket */
 315
 316 static void retry_outgoing_handler(int fd, short events, void *data) {
 317         setup_outgoing_connection(data);
 318 }
 319
 320 void retry_outgoing(outgoing_t *outgoing) {
 321         outgoing->timeout += 5;
 322
 323         if(outgoing->timeout > maxtimeout)
 324                 outgoing->timeout = maxtimeout;
 325
 326         timeout_set(&outgoing->ev, retry_outgoing_handler, outgoing);
 327         event_add(&outgoing->ev, &(struct timeval){outgoing->timeout, 0});
 328
 329         ifdebug(CONNECTIONS) logger(LOG_NOTICE,
 330                            "Trying to re-establish outgoing connection in %d seconds",
 331                            outgoing->timeout);
 332 }
 333
 334 void finish_connecting(connection_t *c) {
 335         ifdebug(CONNECTIONS) logger(LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 336
 337         configure_tcp(c);
 338
 339         c->last_ping_time = time(NULL);
 340         c->status.connecting = false;
 341
 342         send_id(c);
 343 }
 344
 345 void do_outgoing_connection(connection_t *c) {
 346         char *address, *port, *space;
 347         int result;
 348
 349         if(!c->outgoing) {
 350                 logger(LOG_ERR, "do_outgoing_connection() for %s called without c->outgoing", c->name);
 351                 abort();
 352         }
 353
 354 begin:
 355         if(!c->outgoing->ai) {
 356                 if(!c->outgoing->cfg) {
 357                         ifdebug(CONNECTIONS) logger(LOG_ERR, "Could not set up a meta connection to %s",
 358                                            c->name);
 359                         retry_outgoing(c->outgoing);
 360                         c->outgoing = NULL;
 361                         connection_del(c);
 362                         return;
 363                 }
 364
 365                 get_config_string(c->outgoing->cfg, &address);
 366
 367                 space = strchr(address, ' ');
 368                 if(space) {
 369                         port = xstrdup(space + 1);
 370                         *space = 0;
 371                 } else {
 372                         if(!get_config_string(lookup_config(c->config_tree, "Port"), &port))
 373                                 port = xstrdup("655");
 374                 }
 375
 376                 c->outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 377                 free(address);
 378                 free(port);
 379
 380                 c->outgoing->aip = c->outgoing->ai;
 381                 c->outgoing->cfg = lookup_config_next(c->config_tree, c->outgoing->cfg);
 382         }
 383
 384         if(!c->outgoing->aip) {
 385                 if(c->outgoing->ai)
 386                         freeaddrinfo(c->outgoing->ai);
 387                 c->outgoing->ai = NULL;
 388                 goto begin;
 389         }
 390
 391         memcpy(&c->address, c->outgoing->aip->ai_addr, c->outgoing->aip->ai_addrlen);
 392         c->outgoing->aip = c->outgoing->aip->ai_next;
 393
 394         if(c->hostname)
 395                 free(c->hostname);
 396
 397         c->hostname = sockaddr2hostname(&c->address);
 398
 399         ifdebug(CONNECTIONS) logger(LOG_INFO, "Trying to connect to %s (%s)", c->name,
 400                            c->hostname);
 401
 402         c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 403
 404         if(c->socket == -1) {
 405                 ifdebug(CONNECTIONS) logger(LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
 406                 goto begin;
 407         }
 408
 409 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 410         int option = 1;
 411         if(c->address.sa.sa_family == AF_INET6)
 412                 setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 413 #endif
 414
 415         bind_to_interface(c->socket);
 416         bind_to_address(c);
 417
 418         /* Optimize TCP settings */
 419
 420         configure_tcp(c);
 421
 422         /* Connect */
 423
 424         result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 425
 426         if(result == -1) {
 427                 if(sockinprogress(sockerrno)) {
 428                         c->status.connecting = true;
 429                         return;
 430                 }
 431
 432                 closesocket(c->socket);
 433
 434                 ifdebug(CONNECTIONS) logger(LOG_ERR, "%s: %s", c->hostname, sockstrerror(sockerrno));
 435
 436                 goto begin;
 437         }
 438
 439         finish_connecting(c);
 440
 441         return;
 442 }
 443
 444 void handle_meta_read(struct bufferevent *event, void *data) {
 445         logger(LOG_ERR, "handle_meta_read() called");
 446         abort();
 447 }
 448
 449 void handle_meta_write(struct bufferevent *event, void *data) {
 450         ifdebug(META) logger(LOG_DEBUG, "handle_meta_write() called");
 451 }
 452
 453 void handle_meta_connection_error(struct bufferevent *event, short what, void *data) {
 454         connection_t *c = data;
 455         logger(LOG_ERR, "handle_meta_connection_error() called: %d: %s", what, strerror(errno));
 456         terminate_connection(c, c->status.active);
 457 }
 458
 459 void setup_outgoing_connection(outgoing_t *outgoing) {
 460         connection_t *c;
 461         node_t *n;
 462
 463         event_del(&outgoing->ev);
 464
 465         n = lookup_node(outgoing->name);
 466
 467         if(n)
 468                 if(n->connection) {
 469                         ifdebug(CONNECTIONS) logger(LOG_INFO, "Already connected to %s", outgoing->name);
 470
 471                         n->connection->outgoing = outgoing;
 472                         return;
 473                 }
 474
 475         c = new_connection();
 476         c->name = xstrdup(outgoing->name);
 477         c->outcipher = myself->connection->outcipher;
 478         c->outdigest = myself->connection->outdigest;
 479         c->outmaclength = myself->connection->outmaclength;
 480         c->outcompression = myself->connection->outcompression;
 481
 482         init_configuration(&c->config_tree);
 483         read_connection_config(c);
 484
 485         outgoing->cfg = lookup_config(c->config_tree, "Address");
 486
 487         if(!outgoing->cfg) {
 488                 logger(LOG_ERR, "No address specified for %s", c->name);
 489                 free_connection(c);
 490                 return;
 491         }
 492
 493         c->outgoing = outgoing;
 494         c->last_ping_time = time(NULL);
 495
 496         connection_add(c);
 497
 498         do_outgoing_connection(c);
 499
 500         event_set(&c->inevent, c->socket, EV_READ | EV_PERSIST, handle_meta_connection_data, c);
 501         event_add(&c->inevent, NULL);
 502         c->buffer = bufferevent_new(c->socket, handle_meta_read, handle_meta_write, handle_meta_connection_error, c);
 503         if(!c->buffer) {
 504                 logger(LOG_ERR, "bufferevent_new() failed: %s", strerror(errno));
 505                 abort();
 506         }
 507         bufferevent_disable(c->buffer, EV_READ);
 508 }
 509
 510 /*
 511   accept a new tcp connect and create a
 512   new connection
 513 */
 514 void handle_new_meta_connection(int sock, short events, void *data) {
 515         connection_t *c;
 516         sockaddr_t sa;
 517         int fd;
 518         socklen_t len = sizeof sa;
 519
 520         fd = accept(sock, &sa.sa, &len);
 521
 522         if(fd < 0) {
 523                 logger(LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 524                 return;
 525         }
 526
 527         sockaddrunmap(&sa);
 528
 529         c = new_connection();
 530         c->name = xstrdup("<unknown>");
 531         c->outcipher = myself->connection->outcipher;
 532         c->outdigest = myself->connection->outdigest;
 533         c->outmaclength = myself->connection->outmaclength;
 534         c->outcompression = myself->connection->outcompression;
 535
 536         c->address = sa;
 537         c->hostname = sockaddr2hostname(&sa);
 538         c->socket = fd;
 539         c->last_ping_time = time(NULL);
 540
 541         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection from %s", c->hostname);
 542
 543         event_set(&c->inevent, c->socket, EV_READ | EV_PERSIST, handle_meta_connection_data, c);
 544         event_add(&c->inevent, NULL);
 545         c->buffer = bufferevent_new(c->socket, NULL, handle_meta_write, handle_meta_connection_error, c);
 546         if(!c->buffer) {
 547                 logger(LOG_ERR, "bufferevent_new() failed: %s", strerror(errno));
 548                 abort();
 549         }
 550         bufferevent_disable(c->buffer, EV_READ);
 551
 552         configure_tcp(c);
 553
 554         connection_add(c);
 555
 556         c->allow_request = ID;
 557         send_id(c);
 558 }
 559
 560 void free_outgoing(outgoing_t *outgoing) {
 561         if(outgoing->ai)
 562                 freeaddrinfo(outgoing->ai);
 563
 564         if(outgoing->name)
 565                 free(outgoing->name);
 566
 567         free(outgoing);
 568 }
 569
 570 void try_outgoing_connections(void) {
 571         static config_t *cfg = NULL;
 572         char *name;
 573         outgoing_t *outgoing;
 574
 575         outgoing_list = list_alloc((list_action_t)free_outgoing);
 576
 577         for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 578                 get_config_string(cfg, &name);
 579
 580                 if(!check_id(name)) {
 581                         logger(LOG_ERR,
 582                                    "Invalid name for outgoing connection in %s line %d",
 583                                    cfg->file, cfg->line);
 584                         free(name);
 585                         continue;
 586                 }
 587
 588                 outgoing = xmalloc_and_zero(sizeof *outgoing);
 589                 outgoing->name = name;
 590                 list_insert_tail(outgoing_list, outgoing);
 591                 setup_outgoing_connection(outgoing);
 592         }
 593 }