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                   2000-2012 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 #include <assert.h>
  38
  39 /* Needed on Mac OS/X */
  40 #ifndef SOL_TCP
  41 #define SOL_TCP IPPROTO_TCP
  42 #endif
  43
  44 int addressfamily = AF_UNSPEC;
  45 int maxtimeout = 900;
  46 int seconds_till_retry = 5;
  47 int udp_rcvbuf = 0;
  48 int udp_sndbuf = 0;
  49
  50 listen_socket_t listen_socket[MAXSOCKETS];
  51 int listen_sockets;
  52 list_t *outgoing_list = NULL;
  53
  54 /* Setup sockets */
  55
  56 static void configure_tcp(connection_t *c) {
  57         int option;
  58
  59 #ifdef O_NONBLOCK
  60         int flags = fcntl(c->socket, F_GETFL);
  61
  62         if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
  63                 logger(LOG_ERR, "fcntl for %s: %s", c->hostname, strerror(errno));
  64         }
  65 #elif defined(WIN32)
  66         unsigned long arg = 1;
  67
  68         if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
  69                 logger(LOG_ERR, "ioctlsocket for %s: %d", c->hostname, sockstrerror(sockerrno));
  70         }
  71 #endif
  72
  73 #if defined(SOL_TCP) && defined(TCP_NODELAY)
  74         option = 1;
  75         setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&option, sizeof(option));
  76 #endif
  77
  78 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
  79         option = IPTOS_LOWDELAY;
  80         setsockopt(c->socket, SOL_IP, IP_TOS, (void *)&option, sizeof(option));
  81 #endif
  82 }
  83
  84 static bool bind_to_interface(int sd) {
  85         char *iface;
  86
  87 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  88         struct ifreq ifr;
  89         int status;
  90 #endif /* defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) */
  91
  92         if(!get_config_string (lookup_config (config_tree, "BindToInterface"), &iface))
  93                 return true;
  94
  95 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  96         memset(&ifr, 0, sizeof(ifr));
  97         strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
  98         ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
  99
 100         status = setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr));
 101         if(status) {
 102                 logger(LOG_ERR, "Can't bind to interface %s: %s", iface,
 103                                 strerror(errno));
 104                 return false;
 105         }
 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 static bool bind_to_address(connection_t *c) {
 114         char *node;
 115         struct addrinfo *ai_list;
 116         struct addrinfo *ai_ptr;
 117         struct addrinfo ai_hints;
 118         int status;
 119
 120         assert(c != NULL);
 121         assert(c->socket >= 0);
 122
 123         node = NULL;
 124         if(!get_config_string(lookup_config(config_tree, "BindToAddress"),
 125                                 &node))
 126                 return true;
 127
 128         assert(node != NULL);
 129
 130         memset(&ai_hints, 0, sizeof(ai_hints));
 131         ai_hints.ai_family = c->address.sa.sa_family;
 132         /* We're called from `do_outgoing_connection' only. */
 133         ai_hints.ai_socktype = SOCK_STREAM;
 134         ai_hints.ai_protocol = IPPROTO_TCP;
 135
 136         ai_list = NULL;
 137
 138         status = getaddrinfo(node, /* service = */ NULL,
 139                         &ai_hints, &ai_list);
 140         if(status) {
 141                 free(node);
 142                 logger(LOG_WARNING, "Error looking up %s port %s: %s",
 143                                 node, "any", gai_strerror(status));
 144                 return false;
 145         }
 146         assert(ai_list != NULL);
 147
 148         status = -1;
 149         for(ai_ptr = ai_list; ai_ptr != NULL; ai_ptr = ai_ptr->ai_next) {
 150                 status = bind(c->socket,
 151                                 ai_list->ai_addr, ai_list->ai_addrlen);
 152                 if(!status)
 153                         break;
 154         }
 155
 156
 157         if(status) {
 158                 logger(LOG_ERR, "Can't bind to %s/tcp: %s", node, sockstrerror(sockerrno));
 159         } else ifdebug(CONNECTIONS) {
 160                 logger(LOG_DEBUG, "Successfully bound outgoing "
 161                                 "TCP socket to %s", node);
 162         }
 163
 164         free(node);
 165         freeaddrinfo(ai_list);
 166
 167         return status ? false : true;
 168 }
 169
 170 int setup_listen_socket(const sockaddr_t *sa) {
 171         int nfd;
 172         char *addrstr;
 173         int option;
 174         char *iface;
 175
 176         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 177
 178         if(nfd < 0) {
 179                 ifdebug(STATUS) logger(LOG_ERR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
 180                 return -1;
 181         }
 182
 183 #ifdef FD_CLOEXEC
 184         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 185 #endif
 186
 187         /* Optimize TCP settings */
 188
 189         option = 1;
 190         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
 191
 192 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 193         if(sa->sa.sa_family == AF_INET6)
 194                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 195 #endif
 196
 197         if(get_config_string
 198            (lookup_config(config_tree, "BindToInterface"), &iface)) {
 199 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
 200                 struct ifreq ifr;
 201
 202                 memset(&ifr, 0, sizeof(ifr));
 203                 strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
 204
 205                 if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr))) {
 206                         closesocket(nfd);
 207                         logger(LOG_ERR, "Can't bind to interface %s: %s", iface,
 208                                    strerror(sockerrno));
 209                         return -1;
 210                 }
 211 #else
 212                 logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 213 #endif
 214         }
 215
 216         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 217                 closesocket(nfd);
 218                 addrstr = sockaddr2hostname(sa);
 219                 logger(LOG_ERR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
 220                 free(addrstr);
 221                 return -1;
 222         }
 223
 224         if(listen(nfd, 3)) {
 225                 closesocket(nfd);
 226                 logger(LOG_ERR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
 227                 return -1;
 228         }
 229
 230         return nfd;
 231 }
 232
 233 int setup_vpn_in_socket(const sockaddr_t *sa) {
 234         int nfd;
 235         char *addrstr;
 236         int option;
 237
 238         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 239
 240         if(nfd < 0) {
 241                 logger(LOG_ERR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
 242                 return -1;
 243         }
 244
 245 #ifdef FD_CLOEXEC
 246         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 247 #endif
 248
 249 #ifdef O_NONBLOCK
 250         {
 251                 int flags = fcntl(nfd, F_GETFL);
 252
 253                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
 254                         closesocket(nfd);
 255                         logger(LOG_ERR, "System call `%s' failed: %s", "fcntl",
 256                                    strerror(errno));
 257                         return -1;
 258                 }
 259         }
 260 #elif defined(WIN32)
 261         {
 262                 unsigned long arg = 1;
 263                 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
 264                         closesocket(nfd);
 265                         logger(LOG_ERR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
 266                         return -1;
 267                 }
 268         }
 269 #endif
 270
 271         option = 1;
 272         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
 273
 274         if(udp_rcvbuf && setsockopt(nfd, SOL_SOCKET, SO_RCVBUF, (void *)&udp_rcvbuf, sizeof(udp_rcvbuf)))
 275                 logger(LOG_WARNING, "Can't set UDP SO_RCVBUF to %i: %s", udp_rcvbuf, strerror(errno));
 276
 277         if(udp_sndbuf && setsockopt(nfd, SOL_SOCKET, SO_SNDBUF, (void *)&udp_sndbuf, sizeof(udp_sndbuf)))
 278                 logger(LOG_WARNING, "Can't set UDP SO_SNDBUF to %i: %s", udp_sndbuf, strerror(errno));
 279
 280 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
 281         if(sa->sa.sa_family == AF_INET6)
 282                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 283 #endif
 284
 285 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
 286 #define IP_DONTFRAGMENT IP_DONTFRAG
 287 #endif
 288
 289 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 290         if(myself->options & OPTION_PMTU_DISCOVERY) {
 291                 option = IP_PMTUDISC_DO;
 292                 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
 293         }
 294 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
 295         if(myself->options & OPTION_PMTU_DISCOVERY) {
 296                 option = 1;
 297                 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
 298         }
 299 #else
 300 #warning No way to disable IPv4 fragmentation
 301 #endif
 302
 303 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 304         if(myself->options & OPTION_PMTU_DISCOVERY) {
 305                 option = IPV6_PMTUDISC_DO;
 306                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
 307         }
 308 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
 309         if(myself->options & OPTION_PMTU_DISCOVERY) {
 310                 option = 1;
 311                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
 312         }
 313 #else
 314 #warning No way to disable IPv6 fragmentation
 315 #endif
 316
 317         if (!bind_to_interface(nfd)) {
 318                 closesocket(nfd);
 319                 return -1;
 320         }
 321
 322         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 323                 closesocket(nfd);
 324                 addrstr = sockaddr2hostname(sa);
 325                 logger(LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
 326                 free(addrstr);
 327                 return -1;
 328         }
 329
 330         return nfd;
 331 } /* int setup_vpn_in_socket */
 332
 333 void retry_outgoing(outgoing_t *outgoing) {
 334         outgoing->timeout += 5;
 335
 336         if(outgoing->timeout > maxtimeout)
 337                 outgoing->timeout = maxtimeout;
 338
 339         if(outgoing->event)
 340                 event_del(outgoing->event);
 341         outgoing->event = new_event();
 342         outgoing->event->handler = (event_handler_t) setup_outgoing_connection;
 343         outgoing->event->time = now + outgoing->timeout;
 344         outgoing->event->data = outgoing;
 345         event_add(outgoing->event);
 346
 347         ifdebug(CONNECTIONS) logger(LOG_NOTICE,
 348                            "Trying to re-establish outgoing connection in %d seconds",
 349                            outgoing->timeout);
 350 }
 351
 352 void finish_connecting(connection_t *c) {
 353         ifdebug(CONNECTIONS) logger(LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 354
 355         configure_tcp(c);
 356
 357         c->last_ping_time = now;
 358
 359         send_id(c);
 360 }
 361
 362 void do_outgoing_connection(connection_t *c) {
 363         char *address, *port, *space;
 364         int result;
 365
 366         if(!c->outgoing) {
 367                 logger(LOG_ERR, "do_outgoing_connection() for %s called without c->outgoing", c->name);
 368                 abort();
 369         }
 370
 371 begin:
 372         if(!c->outgoing->ai) {
 373                 if(!c->outgoing->cfg) {
 374                         ifdebug(CONNECTIONS) logger(LOG_ERR, "Could not set up a meta connection to %s",
 375                                            c->name);
 376                         c->status.remove = true;
 377                         retry_outgoing(c->outgoing);
 378                         c->outgoing = NULL;
 379                         return;
 380                 }
 381
 382                 get_config_string(c->outgoing->cfg, &address);
 383
 384                 space = strchr(address, ' ');
 385                 if(space) {
 386                         port = xstrdup(space + 1);
 387                         *space = 0;
 388                 } else {
 389                         if(!get_config_string(lookup_config(c->config_tree, "Port"), &port))
 390                                 port = xstrdup("655");
 391                 }
 392
 393                 c->outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 394                 free(address);
 395                 free(port);
 396
 397                 c->outgoing->aip = c->outgoing->ai;
 398                 c->outgoing->cfg = lookup_config_next(c->config_tree, c->outgoing->cfg);
 399         }
 400
 401         if(!c->outgoing->aip) {
 402                 if(c->outgoing->ai)
 403                         freeaddrinfo(c->outgoing->ai);
 404                 c->outgoing->ai = NULL;
 405                 goto begin;
 406         }
 407
 408         memcpy(&c->address, c->outgoing->aip->ai_addr, c->outgoing->aip->ai_addrlen);
 409         c->outgoing->aip = c->outgoing->aip->ai_next;
 410
 411         if(c->hostname)
 412                 free(c->hostname);
 413
 414         c->hostname = sockaddr2hostname(&c->address);
 415
 416         ifdebug(CONNECTIONS) logger(LOG_INFO, "Trying to connect to %s (%s)", c->name,
 417                            c->hostname);
 418
 419         c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 420
 421 #ifdef FD_CLOEXEC
 422         fcntl(c->socket, F_SETFD, FD_CLOEXEC);
 423 #endif
 424
 425         if(c->socket == -1) {
 426                 ifdebug(CONNECTIONS) logger(LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
 427                 goto begin;
 428         }
 429
 430 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 431         int option = 1;
 432         if(c->address.sa.sa_family == AF_INET6)
 433                 setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 434 #endif
 435
 436         bind_to_interface(c->socket);
 437         bind_to_address(c);
 438
 439         /* Optimize TCP settings */
 440
 441         configure_tcp(c);
 442
 443         /* Connect */
 444
 445         result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 446
 447         if(result == -1) {
 448                 if(sockinprogress(sockerrno)) {
 449                         c->status.connecting = true;
 450                         return;
 451                 }
 452
 453                 closesocket(c->socket);
 454
 455                 ifdebug(CONNECTIONS) logger(LOG_ERR, "%s: %s", c->hostname, sockstrerror(sockerrno));
 456
 457                 goto begin;
 458         }
 459
 460         finish_connecting(c);
 461
 462         return;
 463 }
 464
 465 void setup_outgoing_connection(outgoing_t *outgoing) {
 466         connection_t *c;
 467         node_t *n;
 468
 469         outgoing->event = NULL;
 470
 471         n = lookup_node(outgoing->name);
 472
 473         if(n)
 474                 if(n->connection) {
 475                         ifdebug(CONNECTIONS) logger(LOG_INFO, "Already connected to %s", outgoing->name);
 476
 477                         n->connection->outgoing = outgoing;
 478                         return;
 479                 }
 480
 481         c = new_connection();
 482         c->name = xstrdup(outgoing->name);
 483         c->outcipher = myself->connection->outcipher;
 484         c->outdigest = myself->connection->outdigest;
 485         c->outmaclength = myself->connection->outmaclength;
 486         c->outcompression = myself->connection->outcompression;
 487
 488         init_configuration(&c->config_tree);
 489         read_connection_config(c);
 490
 491         outgoing->cfg = lookup_config(c->config_tree, "Address");
 492
 493         if(!outgoing->cfg) {
 494                 logger(LOG_ERR, "No address specified for %s", c->name);
 495                 free_connection(c);
 496                 return;
 497         }
 498
 499         c->outgoing = outgoing;
 500         c->last_ping_time = now;
 501
 502         connection_add(c);
 503
 504         do_outgoing_connection(c);
 505 }
 506
 507 /*
 508   accept a new tcp connect and create a
 509   new connection
 510 */
 511 bool handle_new_meta_connection(int sock) {
 512         connection_t *c;
 513         sockaddr_t sa;
 514         int fd;
 515         socklen_t len = sizeof(sa);
 516
 517         fd = accept(sock, &sa.sa, &len);
 518
 519         if(fd < 0) {
 520                 logger(LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 521                 return false;
 522         }
 523
 524         sockaddrunmap(&sa);
 525
 526         c = new_connection();
 527         c->name = xstrdup("<unknown>");
 528         c->outcipher = myself->connection->outcipher;
 529         c->outdigest = myself->connection->outdigest;
 530         c->outmaclength = myself->connection->outmaclength;
 531         c->outcompression = myself->connection->outcompression;
 532
 533         c->address = sa;
 534         c->hostname = sockaddr2hostname(&sa);
 535         c->socket = fd;
 536         c->last_ping_time = now;
 537
 538         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection from %s", c->hostname);
 539
 540         configure_tcp(c);
 541
 542         connection_add(c);
 543
 544         c->allow_request = ID;
 545         send_id(c);
 546
 547         return true;
 548 }
 549
 550 static void free_outgoing(outgoing_t *outgoing) {
 551         if(outgoing->ai)
 552                 freeaddrinfo(outgoing->ai);
 553
 554         if(outgoing->name)
 555                 free(outgoing->name);
 556
 557         free(outgoing);
 558 }
 559
 560 void try_outgoing_connections(void) {
 561         static config_t *cfg = NULL;
 562         char *name;
 563         outgoing_t *outgoing;
 564
 565         outgoing_list = list_alloc((list_action_t)free_outgoing);
 566
 567         for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 568                 get_config_string(cfg, &name);
 569
 570                 if(!check_id(name)) {
 571                         logger(LOG_ERR,
 572                                    "Invalid name for outgoing connection in %s line %d",
 573                                    cfg->file, cfg->line);
 574                         free(name);
 575                         continue;
 576                 }
 577
 578                 outgoing = xmalloc_and_zero(sizeof(*outgoing));
 579                 outgoing->name = name;
 580                 list_insert_tail(outgoing_list, outgoing);
 581                 setup_outgoing_connection(outgoing);
 582         }
 583 }