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                   2000-2013 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 #else
 244 #warning No way to disable IPv4 fragmentation
 245 #endif
 246
 247 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 248         if(myself->options & OPTION_PMTU_DISCOVERY) {
 249                 option = IPV6_PMTUDISC_DO;
 250                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
 251         }
 252 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
 253         if(myself->options & OPTION_PMTU_DISCOVERY) {
 254                 option = 1;
 255                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
 256         }
 257 #else
 258 #warning No way to disable IPv6 fragmentation
 259 #endif
 260
 261         if (!bind_to_interface(nfd)) {
 262                 closesocket(nfd);
 263                 return -1;
 264         }
 265
 266         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 267                 closesocket(nfd);
 268                 addrstr = sockaddr2hostname(sa);
 269                 logger(LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
 270                 free(addrstr);
 271                 return -1;
 272         }
 273
 274         return nfd;
 275 } /* int setup_vpn_in_socket */
 276
 277 void retry_outgoing(outgoing_t *outgoing) {
 278         outgoing->timeout += 5;
 279
 280         if(outgoing->timeout > maxtimeout)
 281                 outgoing->timeout = maxtimeout;
 282
 283         if(outgoing->event)
 284                 event_del(outgoing->event);
 285         outgoing->event = new_event();
 286         outgoing->event->handler = (event_handler_t) setup_outgoing_connection;
 287         outgoing->event->time = now + outgoing->timeout;
 288         outgoing->event->data = outgoing;
 289         event_add(outgoing->event);
 290
 291         ifdebug(CONNECTIONS) logger(LOG_NOTICE,
 292                            "Trying to re-establish outgoing connection in %d seconds",
 293                            outgoing->timeout);
 294 }
 295
 296 void finish_connecting(connection_t *c) {
 297         ifdebug(CONNECTIONS) logger(LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 298
 299         c->last_ping_time = now;
 300
 301         send_id(c);
 302 }
 303
 304 static void do_outgoing_pipe(connection_t *c, char *command) {
 305 #ifndef HAVE_MINGW
 306         int fd[2];
 307
 308         if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd)) {
 309                 logger(LOG_ERR, "Could not create socketpair: %s\n", strerror(errno));
 310                 return;
 311         }
 312
 313         if(fork()) {
 314                 c->socket = fd[0];
 315                 close(fd[1]);
 316                 ifdebug(CONNECTIONS) logger(LOG_DEBUG, "Using proxy %s", command);
 317                 return;
 318         }
 319
 320         close(0);
 321         close(1);
 322         close(fd[0]);
 323         dup2(fd[1], 0);
 324         dup2(fd[1], 1);
 325         close(fd[1]);
 326
 327         // Other filedescriptors should be closed automatically by CLOEXEC
 328
 329         char *host = NULL;
 330         char *port = NULL;
 331
 332         sockaddr2str(&c->address, &host, &port);
 333         setenv("REMOTEADDRESS", host, true);
 334         setenv("REMOTEPORT", port, true);
 335         setenv("NODE", c->name, true);
 336         setenv("NAME", myself->name, true);
 337         if(netname)
 338                 setenv("NETNAME", netname, true);
 339
 340         int result = system(command);
 341         if(result < 0)
 342                 logger(LOG_ERR, "Could not execute %s: %s\n", command, strerror(errno));
 343         else if(result)
 344                 logger(LOG_ERR, "%s exited with non-zero status %d", command, result);
 345         exit(result);
 346 #else
 347         logger(LOG_ERR, "Proxy type exec not supported on this platform!");
 348         return;
 349 #endif
 350 }
 351
 352 void do_outgoing_connection(connection_t *c) {
 353         char *address, *port, *space;
 354         struct addrinfo *proxyai = NULL;
 355         int result;
 356
 357         if(!c->outgoing) {
 358                 logger(LOG_ERR, "do_outgoing_connection() for %s called without c->outgoing", c->name);
 359                 abort();
 360         }
 361
 362 begin:
 363         if(!c->outgoing->ai) {
 364                 if(!c->outgoing->cfg) {
 365                         ifdebug(CONNECTIONS) logger(LOG_ERR, "Could not set up a meta connection to %s",
 366                                            c->name);
 367                         c->status.remove = true;
 368                         retry_outgoing(c->outgoing);
 369                         c->outgoing = NULL;
 370                         return;
 371                 }
 372
 373                 get_config_string(c->outgoing->cfg, &address);
 374
 375                 space = strchr(address, ' ');
 376                 if(space) {
 377                         port = xstrdup(space + 1);
 378                         *space = 0;
 379                 } else {
 380                         if(!get_config_string(lookup_config(c->config_tree, "Port"), &port))
 381                                 port = xstrdup("655");
 382                 }
 383
 384                 c->outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 385                 free(address);
 386                 free(port);
 387
 388                 c->outgoing->aip = c->outgoing->ai;
 389                 c->outgoing->cfg = lookup_config_next(c->config_tree, c->outgoing->cfg);
 390         }
 391
 392         if(!c->outgoing->aip) {
 393                 if(c->outgoing->ai)
 394                         freeaddrinfo(c->outgoing->ai);
 395                 c->outgoing->ai = NULL;
 396                 goto begin;
 397         }
 398
 399         memcpy(&c->address, c->outgoing->aip->ai_addr, c->outgoing->aip->ai_addrlen);
 400         c->outgoing->aip = c->outgoing->aip->ai_next;
 401
 402         if(c->hostname)
 403                 free(c->hostname);
 404
 405         c->hostname = sockaddr2hostname(&c->address);
 406
 407         ifdebug(CONNECTIONS) logger(LOG_INFO, "Trying to connect to %s (%s)", c->name,
 408                            c->hostname);
 409
 410         if(!proxytype) {
 411                 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 412         } else if(proxytype == PROXY_EXEC) {
 413                 do_outgoing_pipe(c, proxyhost);
 414         } else {
 415                 proxyai = str2addrinfo(proxyhost, proxyport, SOCK_STREAM);
 416                 if(!proxyai)
 417                         goto begin;
 418                 ifdebug(CONNECTIONS) logger(LOG_INFO, "Using proxy at %s port %s", proxyhost, proxyport);
 419                 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
 420         }
 421
 422         if(c->socket == -1) {
 423                 ifdebug(CONNECTIONS) logger(LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
 424                 goto begin;
 425         }
 426
 427         if(proxytype != PROXY_EXEC)
 428                 configure_tcp(c);
 429
 430 #ifdef FD_CLOEXEC
 431         fcntl(c->socket, F_SETFD, FD_CLOEXEC);
 432 #endif
 433
 434         if(proxytype != PROXY_EXEC) {
 435 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 436                 int option = 1;
 437                 if(c->address.sa.sa_family == AF_INET6)
 438                         setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 439 #endif
 440
 441                 bind_to_interface(c->socket);
 442         }
 443
 444         /* Connect */
 445
 446         if(!proxytype) {
 447                 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 448         } else if(proxytype == PROXY_EXEC) {
 449                 result = 0;
 450         } else {
 451                 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
 452                 freeaddrinfo(proxyai);
 453         }
 454
 455         if(result == -1) {
 456                 if(sockinprogress(sockerrno)) {
 457                         c->status.connecting = true;
 458                         return;
 459                 }
 460
 461                 closesocket(c->socket);
 462
 463                 ifdebug(CONNECTIONS) logger(LOG_ERR, "%s: %s", c->hostname, sockstrerror(sockerrno));
 464
 465                 goto begin;
 466         }
 467
 468         finish_connecting(c);
 469
 470         return;
 471 }
 472
 473 void setup_outgoing_connection(outgoing_t *outgoing) {
 474         connection_t *c;
 475         node_t *n;
 476
 477         outgoing->event = NULL;
 478
 479         n = lookup_node(outgoing->name);
 480
 481         if(n)
 482                 if(n->connection) {
 483                         ifdebug(CONNECTIONS) logger(LOG_INFO, "Already connected to %s", outgoing->name);
 484
 485                         n->connection->outgoing = outgoing;
 486                         return;
 487                 }
 488
 489         c = new_connection();
 490         c->name = xstrdup(outgoing->name);
 491         c->outcipher = myself->connection->outcipher;
 492         c->outdigest = myself->connection->outdigest;
 493         c->outmaclength = myself->connection->outmaclength;
 494         c->outcompression = myself->connection->outcompression;
 495
 496         init_configuration(&c->config_tree);
 497         read_connection_config(c);
 498
 499         outgoing->cfg = lookup_config(c->config_tree, "Address");
 500
 501         if(!outgoing->cfg) {
 502                 logger(LOG_ERR, "No address specified for %s", c->name);
 503                 free_connection(c);
 504                 return;
 505         }
 506
 507         c->outgoing = outgoing;
 508         c->last_ping_time = now;
 509
 510         connection_add(c);
 511
 512         do_outgoing_connection(c);
 513 }
 514
 515 /*
 516   accept a new tcp connect and create a
 517   new connection
 518 */
 519 bool handle_new_meta_connection(int sock) {
 520         connection_t *c;
 521         sockaddr_t sa;
 522         int fd;
 523         socklen_t len = sizeof(sa);
 524
 525         fd = accept(sock, &sa.sa, &len);
 526
 527         if(fd < 0) {
 528                 logger(LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 529                 return false;
 530         }
 531
 532         sockaddrunmap(&sa);
 533
 534         c = new_connection();
 535         c->name = xstrdup("<unknown>");
 536         c->outcipher = myself->connection->outcipher;
 537         c->outdigest = myself->connection->outdigest;
 538         c->outmaclength = myself->connection->outmaclength;
 539         c->outcompression = myself->connection->outcompression;
 540
 541         c->address = sa;
 542         c->hostname = sockaddr2hostname(&sa);
 543         c->socket = fd;
 544         c->last_ping_time = now;
 545
 546         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection from %s", c->hostname);
 547
 548         configure_tcp(c);
 549
 550         connection_add(c);
 551
 552         c->allow_request = ID;
 553         send_id(c);
 554
 555         return true;
 556 }
 557
 558 static void free_outgoing(outgoing_t *outgoing) {
 559         if(outgoing->ai)
 560                 freeaddrinfo(outgoing->ai);
 561
 562         if(outgoing->name)
 563                 free(outgoing->name);
 564
 565         free(outgoing);
 566 }
 567
 568 void try_outgoing_connections(void) {
 569         static config_t *cfg = NULL;
 570         char *name;
 571         outgoing_t *outgoing;
 572
 573         outgoing_list = list_alloc((list_action_t)free_outgoing);
 574
 575         for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 576                 get_config_string(cfg, &name);
 577
 578                 if(!check_id(name)) {
 579                         logger(LOG_ERR,
 580                                    "Invalid name for outgoing connection in %s line %d",
 581                                    cfg->file, cfg->line);
 582                         free(name);
 583                         continue;
 584                 }
 585
 586                 outgoing = xmalloc_and_zero(sizeof(*outgoing));
 587                 outgoing->name = name;
 588                 list_insert_tail(outgoing_list, outgoing);
 589                 setup_outgoing_connection(outgoing);
 590         }
 591 }