www.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 mintimeout = 0;
  44 int maxtimeout = 900;
  45 int seconds_till_retry = 5;
  46 int udp_rcvbuf = 0;
  47 int udp_sndbuf = 0;
  48
  49 listen_socket_t listen_socket[MAXSOCKETS];
  50 int listen_sockets;
  51 list_t *outgoing_list = NULL;
  52
  53 /* Setup sockets */
  54
  55 static void configure_tcp(connection_t *c) {
  56         int option;
  57
  58 #ifdef O_NONBLOCK
  59         int flags = fcntl(c->socket, F_GETFL);
  60
  61         if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
  62                 logger(LOG_ERR, "fcntl for %s: %s", c->hostname, strerror(errno));
  63         }
  64 #elif defined(WIN32)
  65         unsigned long arg = 1;
  66
  67         if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
  68                 logger(LOG_ERR, "ioctlsocket for %s: %s", c->hostname, sockstrerror(sockerrno));
  69         }
  70 #endif
  71
  72 #if defined(SOL_TCP) && defined(TCP_NODELAY)
  73         option = 1;
  74         setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&option, sizeof(option));
  75 #endif
  76
  77 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
  78         option = IPTOS_LOWDELAY;
  79         setsockopt(c->socket, SOL_IP, IP_TOS, (void *)&option, sizeof(option));
  80 #endif
  81
  82 #if defined(IPPROTO_IPV6) && defined(IPV6_TCLASS) && defined(IPTOS_LOWDELAY)
  83         option = IPTOS_LOWDELAY;
  84         setsockopt(c->socket, IPPROTO_IPV6, IPV6_TCLASS, (void *)&option, sizeof(option));
  85 #endif
  86 }
  87
  88 static bool bind_to_interface(int sd) {
  89         char *iface;
  90
  91 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  92         struct ifreq ifr;
  93         int status;
  94 #endif /* defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) */
  95
  96         if(!get_config_string(lookup_config (config_tree, "BindToInterface"), &iface))
  97                 return true;
  98
  99 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
 100         memset(&ifr, 0, sizeof(ifr));
 101         strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
 102         ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
 103         free(iface);
 104
 105         status = setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr));
 106         if(status) {
 107                 logger(LOG_ERR, "Can't bind to interface %s: %s", ifr.ifr_ifrn.ifrn_name, strerror(errno));
 108                 return false;
 109         }
 110
 111 #else /* if !defined(SOL_SOCKET) || !defined(SO_BINDTODEVICE) */
 112         logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 113 #endif
 114
 115         return true;
 116 }
 117
 118 int setup_listen_socket(const sockaddr_t *sa) {
 119         int nfd;
 120         char *addrstr;
 121         int option;
 122         char *iface;
 123
 124         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 125
 126         if(nfd < 0) {
 127                 ifdebug(STATUS) logger(LOG_ERR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
 128                 return -1;
 129         }
 130
 131 #ifdef FD_CLOEXEC
 132         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 133 #endif
 134
 135         /* Optimize TCP settings */
 136
 137         option = 1;
 138         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
 139
 140 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 141         if(sa->sa.sa_family == AF_INET6)
 142                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 143 #endif
 144
 145         if(get_config_string(lookup_config(config_tree, "BindToInterface"), &iface)) {
 146 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
 147                 struct ifreq ifr;
 148
 149                 memset(&ifr, 0, sizeof(ifr));
 150                 strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
 151                 ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
 152                 free(iface);
 153
 154                 if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr))) {
 155                         closesocket(nfd);
 156                         logger(LOG_ERR, "Can't bind to interface %s: %s", ifr.ifr_ifrn.ifrn_name, strerror(sockerrno));
 157                         return -1;
 158                 }
 159
 160 #else
 161                 logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 162 #endif
 163         }
 164
 165         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 166                 closesocket(nfd);
 167                 addrstr = sockaddr2hostname(sa);
 168                 logger(LOG_ERR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
 169                 free(addrstr);
 170                 return -1;
 171         }
 172
 173         if(listen(nfd, 3)) {
 174                 closesocket(nfd);
 175                 logger(LOG_ERR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
 176                 return -1;
 177         }
 178
 179         return nfd;
 180 }
 181
 182 int setup_vpn_in_socket(const sockaddr_t *sa) {
 183         int nfd;
 184         char *addrstr;
 185         int option;
 186
 187         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 188
 189         if(nfd < 0) {
 190                 logger(LOG_ERR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
 191                 return -1;
 192         }
 193
 194 #ifdef FD_CLOEXEC
 195         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 196 #endif
 197
 198 #ifdef O_NONBLOCK
 199         {
 200                 int flags = fcntl(nfd, F_GETFL);
 201
 202                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
 203                         closesocket(nfd);
 204                         logger(LOG_ERR, "System call `%s' failed: %s", "fcntl",
 205                                    strerror(errno));
 206                         return -1;
 207                 }
 208         }
 209 #elif defined(WIN32)
 210         {
 211                 unsigned long arg = 1;
 212                 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
 213                         closesocket(nfd);
 214                         logger(LOG_ERR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
 215                         return -1;
 216                 }
 217         }
 218 #endif
 219
 220         option = 1;
 221         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
 222         setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof(option));
 223
 224         if(udp_rcvbuf && setsockopt(nfd, SOL_SOCKET, SO_RCVBUF, (void *)&udp_rcvbuf, sizeof(udp_rcvbuf)))
 225                 logger(LOG_WARNING, "Can't set UDP SO_RCVBUF to %i: %s", udp_rcvbuf, strerror(errno));
 226
 227         if(udp_sndbuf && setsockopt(nfd, SOL_SOCKET, SO_SNDBUF, (void *)&udp_sndbuf, sizeof(udp_sndbuf)))
 228                 logger(LOG_WARNING, "Can't set UDP SO_SNDBUF to %i: %s", udp_sndbuf, strerror(errno));
 229
 230 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
 231         if(sa->sa.sa_family == AF_INET6)
 232                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 233 #endif
 234
 235 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
 236 #define IP_DONTFRAGMENT IP_DONTFRAG
 237 #endif
 238
 239 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 240         if(myself->options & OPTION_PMTU_DISCOVERY) {
 241                 option = IP_PMTUDISC_DO;
 242                 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
 243         }
 244 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
 245         if(myself->options & OPTION_PMTU_DISCOVERY) {
 246                 option = 1;
 247                 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
 248         }
 249 #endif
 250
 251 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 252         if(myself->options & OPTION_PMTU_DISCOVERY) {
 253                 option = IPV6_PMTUDISC_DO;
 254                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
 255         }
 256 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
 257         if(myself->options & OPTION_PMTU_DISCOVERY) {
 258                 option = 1;
 259                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
 260         }
 261 #endif
 262
 263         if (!bind_to_interface(nfd)) {
 264                 closesocket(nfd);
 265                 return -1;
 266         }
 267
 268         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 269                 closesocket(nfd);
 270                 addrstr = sockaddr2hostname(sa);
 271                 logger(LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
 272                 free(addrstr);
 273                 return -1;
 274         }
 275
 276         return nfd;
 277 } /* int setup_vpn_in_socket */
 278
 279 void retry_outgoing(outgoing_t *outgoing) {
 280         outgoing->timeout += 5;
 281
 282         if(outgoing->timeout < mintimeout)
 283                 outgoing->timeout = mintimeout;
 284
 285         if(outgoing->timeout > maxtimeout)
 286                 outgoing->timeout = maxtimeout;
 287
 288         if(outgoing->event)
 289                 event_del(outgoing->event);
 290         outgoing->event = new_event();
 291         outgoing->event->handler = (event_handler_t) setup_outgoing_connection;
 292         outgoing->event->time = now + outgoing->timeout;
 293         outgoing->event->data = outgoing;
 294         event_add(outgoing->event);
 295
 296         ifdebug(CONNECTIONS) logger(LOG_NOTICE,
 297                            "Trying to re-establish outgoing connection in %d seconds",
 298                            outgoing->timeout);
 299 }
 300
 301 void finish_connecting(connection_t *c) {
 302         ifdebug(CONNECTIONS) logger(LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 303
 304         c->last_ping_time = now;
 305
 306         send_id(c);
 307 }
 308
 309 static void do_outgoing_pipe(connection_t *c, char *command) {
 310 #ifndef HAVE_MINGW
 311         int fd[2];
 312
 313         if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd)) {
 314                 logger(LOG_ERR, "Could not create socketpair: %s\n", strerror(errno));
 315                 return;
 316         }
 317
 318         if(fork()) {
 319                 c->socket = fd[0];
 320                 close(fd[1]);
 321                 ifdebug(CONNECTIONS) logger(LOG_DEBUG, "Using proxy %s", command);
 322                 return;
 323         }
 324
 325         close(0);
 326         close(1);
 327         close(fd[0]);
 328         dup2(fd[1], 0);
 329         dup2(fd[1], 1);
 330         close(fd[1]);
 331
 332         // Other filedescriptors should be closed automatically by CLOEXEC
 333
 334         char *host = NULL;
 335         char *port = NULL;
 336
 337         sockaddr2str(&c->address, &host, &port);
 338         setenv("REMOTEADDRESS", host, true);
 339         setenv("REMOTEPORT", port, true);
 340         setenv("NODE", c->name, true);
 341         setenv("NAME", myself->name, true);
 342         if(netname)
 343                 setenv("NETNAME", netname, true);
 344
 345         int result = system(command);
 346         if(result < 0)
 347                 logger(LOG_ERR, "Could not execute %s: %s\n", command, strerror(errno));
 348         else if(result)
 349                 logger(LOG_ERR, "%s exited with non-zero status %d", command, result);
 350         exit(result);
 351 #else
 352         logger(LOG_ERR, "Proxy type exec not supported on this platform!");
 353         return;
 354 #endif
 355 }
 356
 357 void do_outgoing_connection(connection_t *c) {
 358         char *address, *port, *space;
 359         struct addrinfo *proxyai = NULL;
 360         int result;
 361
 362         if(!c->outgoing) {
 363                 logger(LOG_ERR, "do_outgoing_connection() for %s called without c->outgoing", c->name);
 364                 abort();
 365         }
 366
 367 begin:
 368         if(!c->outgoing->ai) {
 369                 if(!c->outgoing->cfg) {
 370                         ifdebug(CONNECTIONS) logger(LOG_ERR, "Could not set up a meta connection to %s",
 371                                            c->name);
 372                         c->status.remove = true;
 373                         retry_outgoing(c->outgoing);
 374                         c->outgoing = NULL;
 375                         return;
 376                 }
 377
 378                 get_config_string(c->outgoing->cfg, &address);
 379
 380                 space = strchr(address, ' ');
 381                 if(space) {
 382                         port = xstrdup(space + 1);
 383                         *space = 0;
 384                 } else {
 385                         if(!get_config_string(lookup_config(c->config_tree, "Port"), &port))
 386                                 port = xstrdup("655");
 387                 }
 388
 389                 c->outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 390                 free(address);
 391                 free(port);
 392
 393                 c->outgoing->aip = c->outgoing->ai;
 394                 c->outgoing->cfg = lookup_config_next(c->config_tree, c->outgoing->cfg);
 395         }
 396
 397         if(!c->outgoing->aip) {
 398                 if(c->outgoing->ai)
 399                         freeaddrinfo(c->outgoing->ai);
 400                 c->outgoing->ai = NULL;
 401                 goto begin;
 402         }
 403
 404         memcpy(&c->address, c->outgoing->aip->ai_addr, c->outgoing->aip->ai_addrlen);
 405         c->outgoing->aip = c->outgoing->aip->ai_next;
 406
 407         if(c->hostname)
 408                 free(c->hostname);
 409
 410         c->hostname = sockaddr2hostname(&c->address);
 411
 412         ifdebug(CONNECTIONS) logger(LOG_INFO, "Trying to connect to %s (%s)", c->name,
 413                            c->hostname);
 414
 415         if(!proxytype) {
 416                 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 417         } else if(proxytype == PROXY_EXEC) {
 418                 do_outgoing_pipe(c, proxyhost);
 419         } else {
 420                 proxyai = str2addrinfo(proxyhost, proxyport, SOCK_STREAM);
 421                 if(!proxyai)
 422                         goto begin;
 423                 ifdebug(CONNECTIONS) logger(LOG_INFO, "Using proxy at %s port %s", proxyhost, proxyport);
 424                 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
 425         }
 426
 427         if(c->socket == -1) {
 428                 ifdebug(CONNECTIONS) logger(LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
 429                 goto begin;
 430         }
 431
 432         if(proxytype != PROXY_EXEC)
 433                 configure_tcp(c);
 434
 435 #ifdef FD_CLOEXEC
 436         fcntl(c->socket, F_SETFD, FD_CLOEXEC);
 437 #endif
 438
 439         if(proxytype != PROXY_EXEC) {
 440 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 441                 int option = 1;
 442                 if(c->address.sa.sa_family == AF_INET6)
 443                         setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 444 #endif
 445
 446                 bind_to_interface(c->socket);
 447         }
 448
 449         /* Connect */
 450
 451         if(!proxytype) {
 452                 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 453         } else if(proxytype == PROXY_EXEC) {
 454                 result = 0;
 455         } else {
 456                 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
 457                 freeaddrinfo(proxyai);
 458         }
 459
 460         if(result == -1) {
 461                 if(sockinprogress(sockerrno)) {
 462                         c->status.connecting = true;
 463                         return;
 464                 }
 465
 466                 closesocket(c->socket);
 467
 468                 ifdebug(CONNECTIONS) logger(LOG_ERR, "%s: %s", c->hostname, sockstrerror(sockerrno));
 469
 470                 goto begin;
 471         }
 472
 473         finish_connecting(c);
 474
 475         return;
 476 }
 477
 478 void setup_outgoing_connection(outgoing_t *outgoing) {
 479         connection_t *c;
 480         node_t *n;
 481
 482         outgoing->event = NULL;
 483
 484         n = lookup_node(outgoing->name);
 485
 486         if(n)
 487                 if(n->connection) {
 488                         ifdebug(CONNECTIONS) logger(LOG_INFO, "Already connected to %s", outgoing->name);
 489
 490                         n->connection->outgoing = outgoing;
 491                         return;
 492                 }
 493
 494         c = new_connection();
 495         c->name = xstrdup(outgoing->name);
 496         c->outcipher = myself->connection->outcipher;
 497         c->outdigest = myself->connection->outdigest;
 498         c->outmaclength = myself->connection->outmaclength;
 499         c->outcompression = myself->connection->outcompression;
 500
 501         init_configuration(&c->config_tree);
 502         read_connection_config(c);
 503
 504         outgoing->cfg = lookup_config(c->config_tree, "Address");
 505
 506         if(!outgoing->cfg) {
 507                 logger(LOG_ERR, "No address specified for %s", c->name);
 508                 free_connection(c);
 509                 return;
 510         }
 511
 512         c->outgoing = outgoing;
 513         c->last_ping_time = now;
 514
 515         connection_add(c);
 516
 517         do_outgoing_connection(c);
 518 }
 519
 520 /*
 521   accept a new tcp connect and create a
 522   new connection
 523 */
 524 bool handle_new_meta_connection(int sock) {
 525         connection_t *c;
 526         sockaddr_t sa;
 527         int fd;
 528         socklen_t len = sizeof(sa);
 529
 530         fd = accept(sock, &sa.sa, &len);
 531
 532         if(fd < 0) {
 533                 logger(LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 534                 return false;
 535         }
 536
 537         sockaddrunmap(&sa);
 538
 539         c = new_connection();
 540         c->name = xstrdup("<unknown>");
 541         c->outcipher = myself->connection->outcipher;
 542         c->outdigest = myself->connection->outdigest;
 543         c->outmaclength = myself->connection->outmaclength;
 544         c->outcompression = myself->connection->outcompression;
 545
 546         c->address = sa;
 547         c->hostname = sockaddr2hostname(&sa);
 548         c->socket = fd;
 549         c->last_ping_time = now;
 550
 551         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection from %s", c->hostname);
 552
 553         configure_tcp(c);
 554
 555         connection_add(c);
 556
 557         c->allow_request = ID;
 558         send_id(c);
 559
 560         return true;
 561 }
 562
 563 static void free_outgoing(outgoing_t *outgoing) {
 564         if(outgoing->ai)
 565                 freeaddrinfo(outgoing->ai);
 566
 567         if(outgoing->name)
 568                 free(outgoing->name);
 569
 570         free(outgoing);
 571 }
 572
 573 void try_outgoing_connections(void) {
 574         static config_t *cfg = NULL;
 575         char *name;
 576         outgoing_t *outgoing;
 577
 578         outgoing_list = list_alloc((list_action_t)free_outgoing);
 579
 580         for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 581                 get_config_string(cfg, &name);
 582
 583                 if(!check_id(name)) {
 584                         logger(LOG_ERR,
 585                                    "Invalid name for outgoing connection in %s line %d",
 586                                    cfg->file, cfg->line);
 587                         free(name);
 588                         continue;
 589                 }
 590
 591                 outgoing = xmalloc_and_zero(sizeof(*outgoing));
 592                 outgoing->name = name;
 593                 list_insert_tail(outgoing_list, outgoing);
 594                 setup_outgoing_connection(outgoing);
 595         }
 596 }