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                   2000-2014 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 /* Needed on Mac OS/X */
  38 #ifndef SOL_TCP
  39 #define SOL_TCP IPPROTO_TCP
  40 #endif
  41
  42 int addressfamily = AF_UNSPEC;
  43 int maxtimeout = 900;
  44 int seconds_till_retry = 5;
  45 int udp_rcvbuf = 0;
  46 int udp_sndbuf = 0;
  47
  48 listen_socket_t listen_socket[MAXSOCKETS];
  49 int listen_sockets;
  50 list_t *outgoing_list = NULL;
  51
  52 /* Setup sockets */
  53
  54 static void configure_tcp(connection_t *c) {
  55         int option;
  56
  57 #ifdef O_NONBLOCK
  58         int flags = fcntl(c->socket, F_GETFL);
  59
  60         if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
  61                 logger(LOG_ERR, "fcntl for %s: %s", c->hostname, strerror(errno));
  62         }
  63 #elif defined(WIN32)
  64         unsigned long arg = 1;
  65
  66         if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
  67                 logger(LOG_ERR, "ioctlsocket for %s: %s", c->hostname, sockstrerror(sockerrno));
  68         }
  69 #endif
  70
  71 #if defined(SOL_TCP) && defined(TCP_NODELAY)
  72         option = 1;
  73         setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&option, sizeof(option));
  74 #endif
  75
  76 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
  77         option = IPTOS_LOWDELAY;
  78         setsockopt(c->socket, SOL_IP, IP_TOS, (void *)&option, sizeof(option));
  79 #endif
  80 }
  81
  82 static bool bind_to_interface(int sd) {
  83         char *iface;
  84
  85 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  86         struct ifreq ifr;
  87         int status;
  88 #endif /* defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) */
  89
  90         if(!get_config_string(lookup_config (config_tree, "BindToInterface"), &iface))
  91                 return true;
  92
  93 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  94         memset(&ifr, 0, sizeof(ifr));
  95         strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
  96         ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
  97         free(iface);
  98
  99         status = setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr));
 100         if(status) {
 101                 logger(LOG_ERR, "Can't bind to interface %s: %s", ifr.ifr_ifrn.ifrn_name, strerror(errno));
 102                 return false;
 103         }
 104
 105 #else /* if !defined(SOL_SOCKET) || !defined(SO_BINDTODEVICE) */
 106         logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 107 #endif
 108
 109         return true;
 110 }
 111
 112 int setup_listen_socket(const sockaddr_t *sa) {
 113         int nfd;
 114         char *addrstr;
 115         int option;
 116         char *iface;
 117
 118         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 119
 120         if(nfd < 0) {
 121                 ifdebug(STATUS) logger(LOG_ERR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
 122                 return -1;
 123         }
 124
 125 #ifdef FD_CLOEXEC
 126         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 127 #endif
 128
 129         /* Optimize TCP settings */
 130
 131         option = 1;
 132         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
 133
 134 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 135         if(sa->sa.sa_family == AF_INET6)
 136                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 137 #endif
 138
 139         if(get_config_string(lookup_config(config_tree, "BindToInterface"), &iface)) {
 140 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
 141                 struct ifreq ifr;
 142
 143                 memset(&ifr, 0, sizeof(ifr));
 144                 strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
 145                 ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
 146                 free(iface);
 147
 148                 if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr))) {
 149                         closesocket(nfd);
 150                         logger(LOG_ERR, "Can't bind to interface %s: %s", ifr.ifr_ifrn.ifrn_name, strerror(sockerrno));
 151                         return -1;
 152                 }
 153
 154 #else
 155                 logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 156 #endif
 157         }
 158
 159         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 160                 closesocket(nfd);
 161                 addrstr = sockaddr2hostname(sa);
 162                 logger(LOG_ERR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
 163                 free(addrstr);
 164                 return -1;
 165         }
 166
 167         if(listen(nfd, 3)) {
 168                 closesocket(nfd);
 169                 logger(LOG_ERR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
 170                 return -1;
 171         }
 172
 173         return nfd;
 174 }
 175
 176 int setup_vpn_in_socket(const sockaddr_t *sa) {
 177         int nfd;
 178         char *addrstr;
 179         int option;
 180
 181         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 182
 183         if(nfd < 0) {
 184                 logger(LOG_ERR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
 185                 return -1;
 186         }
 187
 188 #ifdef FD_CLOEXEC
 189         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 190 #endif
 191
 192 #ifdef O_NONBLOCK
 193         {
 194                 int flags = fcntl(nfd, F_GETFL);
 195
 196                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
 197                         closesocket(nfd);
 198                         logger(LOG_ERR, "System call `%s' failed: %s", "fcntl",
 199                                    strerror(errno));
 200                         return -1;
 201                 }
 202         }
 203 #elif defined(WIN32)
 204         {
 205                 unsigned long arg = 1;
 206                 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
 207                         closesocket(nfd);
 208                         logger(LOG_ERR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
 209                         return -1;
 210                 }
 211         }
 212 #endif
 213
 214         option = 1;
 215         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
 216         setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof(option));
 217
 218         if(udp_rcvbuf && setsockopt(nfd, SOL_SOCKET, SO_RCVBUF, (void *)&udp_rcvbuf, sizeof(udp_rcvbuf)))
 219                 logger(LOG_WARNING, "Can't set UDP SO_RCVBUF to %i: %s", udp_rcvbuf, strerror(errno));
 220
 221         if(udp_sndbuf && setsockopt(nfd, SOL_SOCKET, SO_SNDBUF, (void *)&udp_sndbuf, sizeof(udp_sndbuf)))
 222                 logger(LOG_WARNING, "Can't set UDP SO_SNDBUF to %i: %s", udp_sndbuf, strerror(errno));
 223
 224 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
 225         if(sa->sa.sa_family == AF_INET6)
 226                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 227 #endif
 228
 229 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
 230 #define IP_DONTFRAGMENT IP_DONTFRAG
 231 #endif
 232
 233 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 234         if(myself->options & OPTION_PMTU_DISCOVERY) {
 235                 option = IP_PMTUDISC_DO;
 236                 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
 237         }
 238 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
 239         if(myself->options & OPTION_PMTU_DISCOVERY) {
 240                 option = 1;
 241                 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
 242         }
 243 #endif
 244
 245 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 246         if(myself->options & OPTION_PMTU_DISCOVERY) {
 247                 option = IPV6_PMTUDISC_DO;
 248                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
 249         }
 250 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
 251         if(myself->options & OPTION_PMTU_DISCOVERY) {
 252                 option = 1;
 253                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
 254         }
 255 #endif
 256
 257         if (!bind_to_interface(nfd)) {
 258                 closesocket(nfd);
 259                 return -1;
 260         }
 261
 262         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 263                 closesocket(nfd);
 264                 addrstr = sockaddr2hostname(sa);
 265                 logger(LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
 266                 free(addrstr);
 267                 return -1;
 268         }
 269
 270         return nfd;
 271 } /* int setup_vpn_in_socket */
 272
 273 void retry_outgoing(outgoing_t *outgoing) {
 274         outgoing->timeout += 5;
 275
 276         if(outgoing->timeout > maxtimeout)
 277                 outgoing->timeout = maxtimeout;
 278
 279         if(outgoing->event)
 280                 event_del(outgoing->event);
 281         outgoing->event = new_event();
 282         outgoing->event->handler = (event_handler_t) setup_outgoing_connection;
 283         outgoing->event->time = now + outgoing->timeout;
 284         outgoing->event->data = outgoing;
 285         event_add(outgoing->event);
 286
 287         ifdebug(CONNECTIONS) logger(LOG_NOTICE,
 288                            "Trying to re-establish outgoing connection in %d seconds",
 289                            outgoing->timeout);
 290 }
 291
 292 void finish_connecting(connection_t *c) {
 293         ifdebug(CONNECTIONS) logger(LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 294
 295         c->last_ping_time = now;
 296
 297         send_id(c);
 298 }
 299
 300 static void do_outgoing_pipe(connection_t *c, char *command) {
 301 #ifndef HAVE_MINGW
 302         int fd[2];
 303
 304         if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd)) {
 305                 logger(LOG_ERR, "Could not create socketpair: %s\n", strerror(errno));
 306                 return;
 307         }
 308
 309         if(fork()) {
 310                 c->socket = fd[0];
 311                 close(fd[1]);
 312                 ifdebug(CONNECTIONS) logger(LOG_DEBUG, "Using proxy %s", command);
 313                 return;
 314         }
 315
 316         close(0);
 317         close(1);
 318         close(fd[0]);
 319         dup2(fd[1], 0);
 320         dup2(fd[1], 1);
 321         close(fd[1]);
 322
 323         // Other filedescriptors should be closed automatically by CLOEXEC
 324
 325         char *host = NULL;
 326         char *port = NULL;
 327
 328         sockaddr2str(&c->address, &host, &port);
 329         setenv("REMOTEADDRESS", host, true);
 330         setenv("REMOTEPORT", port, true);
 331         setenv("NODE", c->name, true);
 332         setenv("NAME", myself->name, true);
 333         if(netname)
 334                 setenv("NETNAME", netname, true);
 335
 336         int result = system(command);
 337         if(result < 0)
 338                 logger(LOG_ERR, "Could not execute %s: %s\n", command, strerror(errno));
 339         else if(result)
 340                 logger(LOG_ERR, "%s exited with non-zero status %d", command, result);
 341         exit(result);
 342 #else
 343         logger(LOG_ERR, "Proxy type exec not supported on this platform!");
 344         return;
 345 #endif
 346 }
 347
 348 void do_outgoing_connection(connection_t *c) {
 349         char *address, *port, *space;
 350         struct addrinfo *proxyai = NULL;
 351         int result;
 352
 353         if(!c->outgoing) {
 354                 logger(LOG_ERR, "do_outgoing_connection() for %s called without c->outgoing", c->name);
 355                 abort();
 356         }
 357
 358 begin:
 359         if(!c->outgoing->ai) {
 360                 if(!c->outgoing->cfg) {
 361                         ifdebug(CONNECTIONS) logger(LOG_ERR, "Could not set up a meta connection to %s",
 362                                            c->name);
 363                         c->status.remove = true;
 364                         retry_outgoing(c->outgoing);
 365                         c->outgoing = NULL;
 366                         return;
 367                 }
 368
 369                 get_config_string(c->outgoing->cfg, &address);
 370
 371                 space = strchr(address, ' ');
 372                 if(space) {
 373                         port = xstrdup(space + 1);
 374                         *space = 0;
 375                 } else {
 376                         if(!get_config_string(lookup_config(c->config_tree, "Port"), &port))
 377                                 port = xstrdup("655");
 378                 }
 379
 380                 c->outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 381                 free(address);
 382                 free(port);
 383
 384                 c->outgoing->aip = c->outgoing->ai;
 385                 c->outgoing->cfg = lookup_config_next(c->config_tree, c->outgoing->cfg);
 386         }
 387
 388         if(!c->outgoing->aip) {
 389                 if(c->outgoing->ai)
 390                         freeaddrinfo(c->outgoing->ai);
 391                 c->outgoing->ai = NULL;
 392                 goto begin;
 393         }
 394
 395         memcpy(&c->address, c->outgoing->aip->ai_addr, c->outgoing->aip->ai_addrlen);
 396         c->outgoing->aip = c->outgoing->aip->ai_next;
 397
 398         if(c->hostname)
 399                 free(c->hostname);
 400
 401         c->hostname = sockaddr2hostname(&c->address);
 402
 403         ifdebug(CONNECTIONS) logger(LOG_INFO, "Trying to connect to %s (%s)", c->name,
 404                            c->hostname);
 405
 406         if(!proxytype) {
 407                 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 408         } else if(proxytype == PROXY_EXEC) {
 409                 do_outgoing_pipe(c, proxyhost);
 410         } else {
 411                 proxyai = str2addrinfo(proxyhost, proxyport, SOCK_STREAM);
 412                 if(!proxyai)
 413                         goto begin;
 414                 ifdebug(CONNECTIONS) logger(LOG_INFO, "Using proxy at %s port %s", proxyhost, proxyport);
 415                 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
 416         }
 417
 418         if(c->socket == -1) {
 419                 ifdebug(CONNECTIONS) logger(LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
 420                 goto begin;
 421         }
 422
 423         if(proxytype != PROXY_EXEC)
 424                 configure_tcp(c);
 425
 426 #ifdef FD_CLOEXEC
 427         fcntl(c->socket, F_SETFD, FD_CLOEXEC);
 428 #endif
 429
 430         if(proxytype != PROXY_EXEC) {
 431 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 432                 int option = 1;
 433                 if(c->address.sa.sa_family == AF_INET6)
 434                         setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 435 #endif
 436
 437                 bind_to_interface(c->socket);
 438         }
 439
 440         /* Connect */
 441
 442         if(!proxytype) {
 443                 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 444         } else if(proxytype == PROXY_EXEC) {
 445                 result = 0;
 446         } else {
 447                 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
 448                 freeaddrinfo(proxyai);
 449         }
 450
 451         if(result == -1) {
 452                 if(sockinprogress(sockerrno)) {
 453                         c->status.connecting = true;
 454                         return;
 455                 }
 456
 457                 closesocket(c->socket);
 458
 459                 ifdebug(CONNECTIONS) logger(LOG_ERR, "%s: %s", c->hostname, sockstrerror(sockerrno));
 460
 461                 goto begin;
 462         }
 463
 464         finish_connecting(c);
 465
 466         return;
 467 }
 468
 469 void setup_outgoing_connection(outgoing_t *outgoing) {
 470         connection_t *c;
 471         node_t *n;
 472
 473         outgoing->event = NULL;
 474
 475         n = lookup_node(outgoing->name);
 476
 477         if(n)
 478                 if(n->connection) {
 479                         ifdebug(CONNECTIONS) logger(LOG_INFO, "Already connected to %s", outgoing->name);
 480
 481                         n->connection->outgoing = outgoing;
 482                         return;
 483                 }
 484
 485         c = new_connection();
 486         c->name = xstrdup(outgoing->name);
 487         c->outcipher = myself->connection->outcipher;
 488         c->outdigest = myself->connection->outdigest;
 489         c->outmaclength = myself->connection->outmaclength;
 490         c->outcompression = myself->connection->outcompression;
 491
 492         init_configuration(&c->config_tree);
 493         read_connection_config(c);
 494
 495         outgoing->cfg = lookup_config(c->config_tree, "Address");
 496
 497         if(!outgoing->cfg) {
 498                 logger(LOG_ERR, "No address specified for %s", c->name);
 499                 free_connection(c);
 500                 return;
 501         }
 502
 503         c->outgoing = outgoing;
 504         c->last_ping_time = now;
 505
 506         connection_add(c);
 507
 508         do_outgoing_connection(c);
 509 }
 510
 511 /*
 512   accept a new tcp connect and create a
 513   new connection
 514 */
 515 bool handle_new_meta_connection(int sock) {
 516         connection_t *c;
 517         sockaddr_t sa;
 518         int fd;
 519         socklen_t len = sizeof(sa);
 520
 521         fd = accept(sock, &sa.sa, &len);
 522
 523         if(fd < 0) {
 524                 logger(LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 525                 return false;
 526         }
 527
 528         sockaddrunmap(&sa);
 529
 530         c = new_connection();
 531         c->name = xstrdup("<unknown>");
 532         c->outcipher = myself->connection->outcipher;
 533         c->outdigest = myself->connection->outdigest;
 534         c->outmaclength = myself->connection->outmaclength;
 535         c->outcompression = myself->connection->outcompression;
 536
 537         c->address = sa;
 538         c->hostname = sockaddr2hostname(&sa);
 539         c->socket = fd;
 540         c->last_ping_time = now;
 541
 542         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection from %s", c->hostname);
 543
 544         configure_tcp(c);
 545
 546         connection_add(c);
 547
 548         c->allow_request = ID;
 549         send_id(c);
 550
 551         return true;
 552 }
 553
 554 static void free_outgoing(outgoing_t *outgoing) {
 555         if(outgoing->ai)
 556                 freeaddrinfo(outgoing->ai);
 557
 558         if(outgoing->name)
 559                 free(outgoing->name);
 560
 561         free(outgoing);
 562 }
 563
 564 void try_outgoing_connections(void) {
 565         static config_t *cfg = NULL;
 566         char *name;
 567         outgoing_t *outgoing;
 568
 569         outgoing_list = list_alloc((list_action_t)free_outgoing);
 570
 571         for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 572                 get_config_string(cfg, &name);
 573
 574                 if(!check_id(name)) {
 575                         logger(LOG_ERR,
 576                                    "Invalid name for outgoing connection in %s line %d",
 577                                    cfg->file, cfg->line);
 578                         free(name);
 579                         continue;
 580                 }
 581
 582                 outgoing = xmalloc_and_zero(sizeof(*outgoing));
 583                 outgoing->name = name;
 584                 list_insert_tail(outgoing_list, outgoing);
 585                 setup_outgoing_connection(outgoing);
 586         }
 587 }