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         free(iface);
 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 int setup_listen_socket(const sockaddr_t *sa) {
 114         int nfd;
 115         char *addrstr;
 116         int option;
 117         char *iface;
 118
 119         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 120
 121         if(nfd < 0) {
 122                 ifdebug(STATUS) logger(LOG_ERR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
 123                 return -1;
 124         }
 125
 126 #ifdef FD_CLOEXEC
 127         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 128 #endif
 129
 130         /* Optimize TCP settings */
 131
 132         option = 1;
 133         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
 134
 135 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 136         if(sa->sa.sa_family == AF_INET6)
 137                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 138 #endif
 139
 140         if(get_config_string(lookup_config(config_tree, "BindToInterface"), &iface)) {
 141 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
 142                 struct ifreq ifr;
 143
 144                 memset(&ifr, 0, sizeof(ifr));
 145                 strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
 146                 ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
 147                 free(iface);
 148
 149                 if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr))) {
 150                         closesocket(nfd);
 151                         logger(LOG_ERR, "Can't bind to interface %s: %s", ifr.ifr_ifrn.ifrn_name, strerror(sockerrno));
 152                         return -1;
 153                 }
 154
 155 #else
 156                 logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 157 #endif
 158         }
 159
 160         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 161                 closesocket(nfd);
 162                 addrstr = sockaddr2hostname(sa);
 163                 logger(LOG_ERR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
 164                 free(addrstr);
 165                 return -1;
 166         }
 167
 168         if(listen(nfd, 3)) {
 169                 closesocket(nfd);
 170                 logger(LOG_ERR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
 171                 return -1;
 172         }
 173
 174         return nfd;
 175 }
 176
 177 int setup_vpn_in_socket(const sockaddr_t *sa) {
 178         int nfd;
 179         char *addrstr;
 180         int option;
 181
 182         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 183
 184         if(nfd < 0) {
 185                 logger(LOG_ERR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
 186                 return -1;
 187         }
 188
 189 #ifdef FD_CLOEXEC
 190         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 191 #endif
 192
 193 #ifdef O_NONBLOCK
 194         {
 195                 int flags = fcntl(nfd, F_GETFL);
 196
 197                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
 198                         closesocket(nfd);
 199                         logger(LOG_ERR, "System call `%s' failed: %s", "fcntl",
 200                                    strerror(errno));
 201                         return -1;
 202                 }
 203         }
 204 #elif defined(WIN32)
 205         {
 206                 unsigned long arg = 1;
 207                 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
 208                         closesocket(nfd);
 209                         logger(LOG_ERR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
 210                         return -1;
 211                 }
 212         }
 213 #endif
 214
 215         option = 1;
 216         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
 217         setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof(option));
 218
 219         if(udp_rcvbuf && setsockopt(nfd, SOL_SOCKET, SO_RCVBUF, (void *)&udp_rcvbuf, sizeof(udp_rcvbuf)))
 220                 logger(LOG_WARNING, "Can't set UDP SO_RCVBUF to %i: %s", udp_rcvbuf, strerror(errno));
 221
 222         if(udp_sndbuf && setsockopt(nfd, SOL_SOCKET, SO_SNDBUF, (void *)&udp_sndbuf, sizeof(udp_sndbuf)))
 223                 logger(LOG_WARNING, "Can't set UDP SO_SNDBUF to %i: %s", udp_sndbuf, strerror(errno));
 224
 225 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
 226         if(sa->sa.sa_family == AF_INET6)
 227                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 228 #endif
 229
 230 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
 231 #define IP_DONTFRAGMENT IP_DONTFRAG
 232 #endif
 233
 234 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 235         if(myself->options & OPTION_PMTU_DISCOVERY) {
 236                 option = IP_PMTUDISC_DO;
 237                 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
 238         }
 239 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
 240         if(myself->options & OPTION_PMTU_DISCOVERY) {
 241                 option = 1;
 242                 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
 243         }
 244 #else
 245 #warning No way to disable IPv4 fragmentation
 246 #endif
 247
 248 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 249         if(myself->options & OPTION_PMTU_DISCOVERY) {
 250                 option = IPV6_PMTUDISC_DO;
 251                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
 252         }
 253 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
 254         if(myself->options & OPTION_PMTU_DISCOVERY) {
 255                 option = 1;
 256                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
 257         }
 258 #else
 259 #warning No way to disable IPv6 fragmentation
 260 #endif
 261
 262         if (!bind_to_interface(nfd)) {
 263                 closesocket(nfd);
 264                 return -1;
 265         }
 266
 267         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 268                 closesocket(nfd);
 269                 addrstr = sockaddr2hostname(sa);
 270                 logger(LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
 271                 free(addrstr);
 272                 return -1;
 273         }
 274
 275         return nfd;
 276 } /* int setup_vpn_in_socket */
 277
 278 void retry_outgoing(outgoing_t *outgoing) {
 279         outgoing->timeout += 5;
 280
 281         if(outgoing->timeout > maxtimeout)
 282                 outgoing->timeout = maxtimeout;
 283
 284         if(outgoing->event)
 285                 event_del(outgoing->event);
 286         outgoing->event = new_event();
 287         outgoing->event->handler = (event_handler_t) setup_outgoing_connection;
 288         outgoing->event->time = now + outgoing->timeout;
 289         outgoing->event->data = outgoing;
 290         event_add(outgoing->event);
 291
 292         ifdebug(CONNECTIONS) logger(LOG_NOTICE,
 293                            "Trying to re-establish outgoing connection in %d seconds",
 294                            outgoing->timeout);
 295 }
 296
 297 void finish_connecting(connection_t *c) {
 298         ifdebug(CONNECTIONS) logger(LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 299
 300         c->last_ping_time = now;
 301
 302         send_id(c);
 303 }
 304
 305 static void do_outgoing_pipe(connection_t *c, char *command) {
 306 #ifndef HAVE_MINGW
 307         int fd[2];
 308
 309         if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd)) {
 310                 logger(LOG_ERR, "Could not create socketpair: %s\n", strerror(errno));
 311                 return;
 312         }
 313
 314         if(fork()) {
 315                 c->socket = fd[0];
 316                 close(fd[1]);
 317                 ifdebug(CONNECTIONS) logger(LOG_DEBUG, "Using proxy %s", command);
 318                 return;
 319         }
 320
 321         close(0);
 322         close(1);
 323         close(fd[0]);
 324         dup2(fd[1], 0);
 325         dup2(fd[1], 1);
 326         close(fd[1]);
 327
 328         // Other filedescriptors should be closed automatically by CLOEXEC
 329
 330         char *host = NULL;
 331         char *port = NULL;
 332
 333         sockaddr2str(&c->address, &host, &port);
 334         setenv("REMOTEADDRESS", host, true);
 335         setenv("REMOTEPORT", port, true);
 336         setenv("NODE", c->name, true);
 337         setenv("NAME", myself->name, true);
 338         if(netname)
 339                 setenv("NETNAME", netname, true);
 340
 341         int result = system(command);
 342         if(result < 0)
 343                 logger(LOG_ERR, "Could not execute %s: %s\n", command, strerror(errno));
 344         else if(result)
 345                 logger(LOG_ERR, "%s exited with non-zero status %d", command, result);
 346         exit(result);
 347 #else
 348         logger(LOG_ERR, "Proxy type exec not supported on this platform!");
 349         return;
 350 #endif
 351 }
 352
 353 void do_outgoing_connection(connection_t *c) {
 354         char *address, *port, *space;
 355         struct addrinfo *proxyai = NULL;
 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         if(!proxytype) {
 412                 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 413         } else if(proxytype == PROXY_EXEC) {
 414                 do_outgoing_pipe(c, proxyhost);
 415         } else {
 416                 proxyai = str2addrinfo(proxyhost, proxyport, SOCK_STREAM);
 417                 if(!proxyai)
 418                         goto begin;
 419                 ifdebug(CONNECTIONS) logger(LOG_INFO, "Using proxy at %s port %s", proxyhost, proxyport);
 420                 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
 421         }
 422
 423         if(c->socket == -1) {
 424                 ifdebug(CONNECTIONS) logger(LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
 425                 goto begin;
 426         }
 427
 428         if(proxytype != PROXY_EXEC)
 429                 configure_tcp(c);
 430
 431 #ifdef FD_CLOEXEC
 432         fcntl(c->socket, F_SETFD, FD_CLOEXEC);
 433 #endif
 434
 435         if(proxytype != PROXY_EXEC) {
 436 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 437                 int option = 1;
 438                 if(c->address.sa.sa_family == AF_INET6)
 439                         setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 440 #endif
 441
 442                 bind_to_interface(c->socket);
 443         }
 444
 445         /* Connect */
 446
 447         if(!proxytype) {
 448                 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 449         } else if(proxytype == PROXY_EXEC) {
 450                 result = 0;
 451         } else {
 452                 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
 453                 freeaddrinfo(proxyai);
 454         }
 455
 456         if(result == -1) {
 457                 if(sockinprogress(sockerrno)) {
 458                         c->status.connecting = true;
 459                         return;
 460                 }
 461
 462                 closesocket(c->socket);
 463
 464                 ifdebug(CONNECTIONS) logger(LOG_ERR, "%s: %s", c->hostname, sockstrerror(sockerrno));
 465
 466                 goto begin;
 467         }
 468
 469         finish_connecting(c);
 470
 471         return;
 472 }
 473
 474 void setup_outgoing_connection(outgoing_t *outgoing) {
 475         connection_t *c;
 476         node_t *n;
 477
 478         outgoing->event = NULL;
 479
 480         n = lookup_node(outgoing->name);
 481
 482         if(n)
 483                 if(n->connection) {
 484                         ifdebug(CONNECTIONS) logger(LOG_INFO, "Already connected to %s", outgoing->name);
 485
 486                         n->connection->outgoing = outgoing;
 487                         return;
 488                 }
 489
 490         c = new_connection();
 491         c->name = xstrdup(outgoing->name);
 492         c->outcipher = myself->connection->outcipher;
 493         c->outdigest = myself->connection->outdigest;
 494         c->outmaclength = myself->connection->outmaclength;
 495         c->outcompression = myself->connection->outcompression;
 496
 497         init_configuration(&c->config_tree);
 498         read_connection_config(c);
 499
 500         outgoing->cfg = lookup_config(c->config_tree, "Address");
 501
 502         if(!outgoing->cfg) {
 503                 logger(LOG_ERR, "No address specified for %s", c->name);
 504                 free_connection(c);
 505                 return;
 506         }
 507
 508         c->outgoing = outgoing;
 509         c->last_ping_time = now;
 510
 511         connection_add(c);
 512
 513         do_outgoing_connection(c);
 514 }
 515
 516 /*
 517   accept a new tcp connect and create a
 518   new connection
 519 */
 520 bool handle_new_meta_connection(int sock) {
 521         connection_t *c;
 522         sockaddr_t sa;
 523         int fd;
 524         socklen_t len = sizeof(sa);
 525
 526         fd = accept(sock, &sa.sa, &len);
 527
 528         if(fd < 0) {
 529                 logger(LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 530                 return false;
 531         }
 532
 533         sockaddrunmap(&sa);
 534
 535         c = new_connection();
 536         c->name = xstrdup("<unknown>");
 537         c->outcipher = myself->connection->outcipher;
 538         c->outdigest = myself->connection->outdigest;
 539         c->outmaclength = myself->connection->outmaclength;
 540         c->outcompression = myself->connection->outcompression;
 541
 542         c->address = sa;
 543         c->hostname = sockaddr2hostname(&sa);
 544         c->socket = fd;
 545         c->last_ping_time = now;
 546
 547         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection from %s", c->hostname);
 548
 549         configure_tcp(c);
 550
 551         connection_add(c);
 552
 553         c->allow_request = ID;
 554         send_id(c);
 555
 556         return true;
 557 }
 558
 559 static void free_outgoing(outgoing_t *outgoing) {
 560         if(outgoing->ai)
 561                 freeaddrinfo(outgoing->ai);
 562
 563         if(outgoing->name)
 564                 free(outgoing->name);
 565
 566         free(outgoing);
 567 }
 568
 569 void try_outgoing_connections(void) {
 570         static config_t *cfg = NULL;
 571         char *name;
 572         outgoing_t *outgoing;
 573
 574         outgoing_list = list_alloc((list_action_t)free_outgoing);
 575
 576         for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 577                 get_config_string(cfg, &name);
 578
 579                 if(!check_id(name)) {
 580                         logger(LOG_ERR,
 581                                    "Invalid name for outgoing connection in %s line %d",
 582                                    cfg->file, cfg->line);
 583                         free(name);
 584                         continue;
 585                 }
 586
 587                 outgoing = xmalloc_and_zero(sizeof(*outgoing));
 588                 outgoing->name = name;
 589                 list_insert_tail(outgoing_list, outgoing);
 590                 setup_outgoing_connection(outgoing);
 591         }
 592 }