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                   2000-2010 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 "splay_tree.h"
  26 #include "conf.h"
  27 #include "connection.h"
  28 #include "logger.h"
  29 #include "meta.h"
  30 #include "net.h"
  31 #include "netutl.h"
  32 #include "protocol.h"
  33 #include "utils.h"
  34 #include "xalloc.h"
  35
  36 #include <assert.h>
  37
  38 /* Needed on Mac OS/X */
  39 #ifndef SOL_TCP
  40 #define SOL_TCP IPPROTO_TCP
  41 #endif
  42
  43 int addressfamily = AF_UNSPEC;
  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 #if defined(SOL_TCP) && defined(TCP_NODELAY)
  59         option = 1;
  60         setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&option, sizeof option);
  61 #endif
  62
  63 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
  64         option = IPTOS_LOWDELAY;
  65         setsockopt(c->socket, SOL_IP, IP_TOS, (void *)&option, sizeof option);
  66 #endif
  67 }
  68
  69 static bool bind_to_interface(int sd) {
  70         char *iface;
  71
  72 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  73         struct ifreq ifr;
  74         int status;
  75 #endif /* defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) */
  76
  77         if(!get_config_string (lookup_config (config_tree, "BindToInterface"), &iface))
  78                 return true;
  79
  80 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  81         memset(&ifr, 0, sizeof(ifr));
  82         strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
  83         ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
  84
  85         status = setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr));
  86         if(status) {
  87                 logger(LOG_ERR, "Can't bind to interface %s: %s", iface,
  88                                 strerror(errno));
  89                 return false;
  90         }
  91 #else /* if !defined(SOL_SOCKET) || !defined(SO_BINDTODEVICE) */
  92         logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
  93 #endif
  94
  95         return true;
  96 }
  97
  98 static bool bind_to_address(connection_t *c) {
  99         char *node;
 100         struct addrinfo *ai_list;
 101         struct addrinfo *ai_ptr;
 102         struct addrinfo ai_hints;
 103         int status;
 104
 105         assert(c != NULL);
 106         assert(c->socket >= 0);
 107
 108         node = NULL;
 109         if(!get_config_string(lookup_config(config_tree, "BindToAddress"),
 110                                 &node))
 111                 return true;
 112
 113         assert(node != NULL);
 114
 115         memset(&ai_hints, 0, sizeof(ai_hints));
 116         ai_hints.ai_family = c->address.sa.sa_family;
 117         /* We're called from `do_outgoing_connection' only. */
 118         ai_hints.ai_socktype = SOCK_STREAM;
 119         ai_hints.ai_protocol = IPPROTO_TCP;
 120
 121         ai_list = NULL;
 122
 123         status = getaddrinfo(node, /* service = */ NULL,
 124                         &ai_hints, &ai_list);
 125         if(status) {
 126                 free(node);
 127                 logger(LOG_WARNING, "Error looking up %s port %s: %s",
 128                                 node, "any", gai_strerror(status));
 129                 return false;
 130         }
 131         assert(ai_list != NULL);
 132
 133         status = -1;
 134         for(ai_ptr = ai_list; ai_ptr != NULL; ai_ptr = ai_ptr->ai_next) {
 135                 status = bind(c->socket,
 136                                 ai_list->ai_addr, ai_list->ai_addrlen);
 137                 if(!status)
 138                         break;
 139         }
 140
 141
 142         if(status) {
 143                 logger(LOG_ERR, "Can't bind to %s/tcp: %s", node, sockstrerror(sockerrno));
 144         } else ifdebug(CONNECTIONS) {
 145                 logger(LOG_DEBUG, "Successfully bound outgoing "
 146                                 "TCP socket to %s", node);
 147         }
 148
 149         free(node);
 150         freeaddrinfo(ai_list);
 151
 152         return status ? false : true;
 153 }
 154
 155 int setup_listen_socket(const sockaddr_t *sa) {
 156         int nfd;
 157         char *addrstr;
 158         int option;
 159         char *iface;
 160
 161         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 162
 163         if(nfd < 0) {
 164                 ifdebug(STATUS) logger(LOG_ERR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
 165                 return -1;
 166         }
 167
 168         /* Optimize TCP settings */
 169
 170         option = 1;
 171         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
 172
 173 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 174         if(sa->sa.sa_family == AF_INET6)
 175                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 176 #endif
 177
 178         if(get_config_string
 179            (lookup_config(config_tree, "BindToInterface"), &iface)) {
 180 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
 181                 struct ifreq ifr;
 182
 183                 memset(&ifr, 0, sizeof ifr);
 184                 strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
 185
 186                 if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof ifr)) {
 187                         closesocket(nfd);
 188                         logger(LOG_ERR, "Can't bind to interface %s: %s", iface,
 189                                    strerror(sockerrno));
 190                         return -1;
 191                 }
 192 #else
 193                 logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 194 #endif
 195         }
 196
 197         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 198                 closesocket(nfd);
 199                 addrstr = sockaddr2hostname(sa);
 200                 logger(LOG_ERR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
 201                 free(addrstr);
 202                 return -1;
 203         }
 204
 205         if(listen(nfd, 3)) {
 206                 closesocket(nfd);
 207                 logger(LOG_ERR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
 208                 return -1;
 209         }
 210
 211         return nfd;
 212 }
 213
 214 int setup_vpn_in_socket(const sockaddr_t *sa) {
 215         int nfd;
 216         char *addrstr;
 217         int option;
 218
 219         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 220
 221         if(nfd < 0) {
 222                 logger(LOG_ERR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
 223                 return -1;
 224         }
 225
 226         option = 1;
 227         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
 228
 229         if(udp_rcvbuf && setsockopt(nfd, SOL_SOCKET, SO_RCVBUF, (void *)&udp_rcvbuf, sizeof(udp_rcvbuf)))
 230                 logger(LOG_WARNING, "Can't set UDP SO_RCVBUF to %i: %s", udp_rcvbuf, strerror(errno));
 231
 232         if(udp_sndbuf && setsockopt(nfd, SOL_SOCKET, SO_SNDBUF, (void *)&udp_sndbuf, sizeof(udp_sndbuf)))
 233                 logger(LOG_WARNING, "Can't set UDP SO_SNDBUF to %i: %s", udp_sndbuf, strerror(errno));
 234
 235 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
 236         if(sa->sa.sa_family == AF_INET6)
 237                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 238 #endif
 239
 240 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
 241 #define IP_DONTFRAGMENT IP_DONTFRAG
 242 #endif
 243
 244 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 245         if(myself->options & OPTION_PMTU_DISCOVERY) {
 246                 option = IP_PMTUDISC_DO;
 247                 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
 248         }
 249 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
 250         if(myself->options & OPTION_PMTU_DISCOVERY) {
 251                 option = 1;
 252                 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
 253         }
 254 #else
 255 #warning No way to disable IPv4 fragmentation
 256 #endif
 257
 258 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 259         if(myself->options & OPTION_PMTU_DISCOVERY) {
 260                 option = IPV6_PMTUDISC_DO;
 261                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
 262         }
 263 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
 264         if(myself->options & OPTION_PMTU_DISCOVERY) {
 265                 option = 1;
 266                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
 267         }
 268 #else
 269 #warning No way to disable IPv6 fragmentation
 270 #endif
 271
 272         if (!bind_to_interface(nfd)) {
 273                 closesocket(nfd);
 274                 return -1;
 275         }
 276
 277         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 278                 closesocket(nfd);
 279                 addrstr = sockaddr2hostname(sa);
 280                 logger(LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
 281                 free(addrstr);
 282                 return -1;
 283         }
 284
 285         return nfd;
 286 } /* int setup_vpn_in_socket */
 287
 288 static void retry_outgoing_handler(void *data) {
 289         setup_outgoing_connection(data);
 290 }
 291
 292 void retry_outgoing(outgoing_t *outgoing) {
 293         outgoing->timeout += 5;
 294
 295         if(outgoing->timeout > maxtimeout)
 296                 outgoing->timeout = maxtimeout;
 297
 298         outgoing->ev.handler = retry_outgoing_handler;
 299         outgoing->ev.time = time(NULL) + outgoing->timeout;
 300         event_add(&outgoing->ev);
 301
 302         ifdebug(CONNECTIONS) logger(LOG_NOTICE,
 303                            "Trying to re-establish outgoing connection in %d seconds",
 304                            outgoing->timeout);
 305 }
 306
 307 void finish_connecting(connection_t *c) {
 308         ifdebug(CONNECTIONS) logger(LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 309
 310         configure_tcp(c);
 311
 312         c->last_ping_time = time(NULL);
 313         c->status.connecting = false;
 314
 315         send_id(c);
 316 }
 317
 318 void do_outgoing_connection(connection_t *c) {
 319         char *address, *port, *space;
 320         int result;
 321
 322         if(!c->outgoing) {
 323                 logger(LOG_ERR, "do_outgoing_connection() for %s called without c->outgoing", c->name);
 324                 abort();
 325         }
 326
 327 begin:
 328         if(!c->outgoing->ai) {
 329                 if(!c->outgoing->cfg) {
 330                         ifdebug(CONNECTIONS) logger(LOG_ERR, "Could not set up a meta connection to %s",
 331                                            c->name);
 332                         retry_outgoing(c->outgoing);
 333                         c->outgoing = NULL;
 334                         connection_del(c);
 335                         return;
 336                 }
 337
 338                 get_config_string(c->outgoing->cfg, &address);
 339
 340                 space = strchr(address, ' ');
 341                 if(space) {
 342                         port = xstrdup(space + 1);
 343                         *space = 0;
 344                 } else {
 345                         if(!get_config_string(lookup_config(c->config_tree, "Port"), &port))
 346                                 port = xstrdup("655");
 347                 }
 348
 349                 c->outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 350                 free(address);
 351                 free(port);
 352
 353                 c->outgoing->aip = c->outgoing->ai;
 354                 c->outgoing->cfg = lookup_config_next(c->config_tree, c->outgoing->cfg);
 355         }
 356
 357         if(!c->outgoing->aip) {
 358                 if(c->outgoing->ai)
 359                         freeaddrinfo(c->outgoing->ai);
 360                 c->outgoing->ai = NULL;
 361                 goto begin;
 362         }
 363
 364         memcpy(&c->address, c->outgoing->aip->ai_addr, c->outgoing->aip->ai_addrlen);
 365         c->outgoing->aip = c->outgoing->aip->ai_next;
 366
 367         if(c->hostname)
 368                 free(c->hostname);
 369
 370         c->hostname = sockaddr2hostname(&c->address);
 371
 372         ifdebug(CONNECTIONS) logger(LOG_INFO, "Trying to connect to %s (%s)", c->name,
 373                            c->hostname);
 374
 375         c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 376
 377         if(c->socket == -1) {
 378                 ifdebug(CONNECTIONS) logger(LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
 379                 goto begin;
 380         }
 381
 382 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 383         int option = 1;
 384         if(c->address.sa.sa_family == AF_INET6)
 385                 setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 386 #endif
 387
 388         bind_to_interface(c->socket);
 389         bind_to_address(c);
 390
 391         /* Optimize TCP settings */
 392
 393         configure_tcp(c);
 394
 395         /* Connect */
 396
 397         result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 398
 399         if(result == -1) {
 400                 if(sockinprogress(sockerrno)) {
 401                         c->status.connecting = true;
 402                         return;
 403                 }
 404
 405                 closesocket(c->socket);
 406
 407                 ifdebug(CONNECTIONS) logger(LOG_ERR, "%s: %s", c->hostname, sockstrerror(sockerrno));
 408
 409                 goto begin;
 410         }
 411
 412         finish_connecting(c);
 413
 414         return;
 415 }
 416
 417 void setup_outgoing_connection(outgoing_t *outgoing) {
 418         connection_t *c;
 419         node_t *n;
 420
 421         event_del(&outgoing->ev);
 422
 423         n = lookup_node(outgoing->name);
 424
 425         if(n)
 426                 if(n->connection) {
 427                         ifdebug(CONNECTIONS) logger(LOG_INFO, "Already connected to %s", outgoing->name);
 428
 429                         n->connection->outgoing = outgoing;
 430                         return;
 431                 }
 432
 433         c = new_connection();
 434         c->name = xstrdup(outgoing->name);
 435         c->outcipher = myself->connection->outcipher;
 436         c->outdigest = myself->connection->outdigest;
 437         c->outmaclength = myself->connection->outmaclength;
 438         c->outcompression = myself->connection->outcompression;
 439
 440         init_configuration(&c->config_tree);
 441         read_connection_config(c);
 442
 443         outgoing->cfg = lookup_config(c->config_tree, "Address");
 444
 445         if(!outgoing->cfg) {
 446                 logger(LOG_ERR, "No address specified for %s", c->name);
 447                 free_connection(c);
 448                 return;
 449         }
 450
 451         c->outgoing = outgoing;
 452         c->last_ping_time = time(NULL);
 453
 454         connection_add(c);
 455
 456         do_outgoing_connection(c);
 457
 458         if(!thread_create(&c->thread, handle_meta_connection_data, c)) {
 459                 logger(LOG_ERR, "create_thread() failed: %s", strerror(errno));
 460                 abort();
 461         }
 462 }
 463
 464 /*
 465   accept a new tcp connect and create a
 466   new connection
 467 */
 468 void handle_new_meta_connection(void *data) {
 469         listen_socket_t *l = data;
 470         connection_t *c;
 471         sockaddr_t sa;
 472         int fd;
 473         socklen_t len = sizeof sa;
 474
 475         while(true) {
 476                 fd = accept(l->tcp, &sa.sa, &len);
 477
 478                 if(fd < 0) {
 479                         logger(LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 480                         return;
 481                 }
 482
 483                 sockaddrunmap(&sa);
 484
 485                 c = new_connection();
 486                 c->name = xstrdup("<unknown>");
 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                 c->address = sa;
 493                 c->hostname = sockaddr2hostname(&sa);
 494                 c->socket = fd;
 495                 c->last_ping_time = time(NULL);
 496
 497                 ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection from %s", c->hostname);
 498
 499                 configure_tcp(c);
 500
 501                 mutex_lock(&mutex);
 502                 connection_add(c);
 503
 504                 c->allow_request = ID;
 505                 send_id(c);
 506
 507                 if(!thread_create(&c->thread, handle_meta_connection_data, c)) {
 508                         logger(LOG_ERR, "create_thread() failed: %s", strerror(errno));
 509                         abort();
 510                 }
 511                 mutex_unlock(&mutex);
 512         }
 513 }
 514
 515 void free_outgoing(outgoing_t *outgoing) {
 516         if(outgoing->ai)
 517                 freeaddrinfo(outgoing->ai);
 518
 519         if(outgoing->name)
 520                 free(outgoing->name);
 521
 522         free(outgoing);
 523 }
 524
 525 void try_outgoing_connections(void) {
 526         static config_t *cfg = NULL;
 527         char *name;
 528         outgoing_t *outgoing;
 529
 530         outgoing_list = list_alloc((list_action_t)free_outgoing);
 531
 532         for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 533                 get_config_string(cfg, &name);
 534
 535                 if(!check_id(name)) {
 536                         logger(LOG_ERR,
 537                                    "Invalid name for outgoing connection in %s line %d",
 538                                    cfg->file, cfg->line);
 539                         free(name);
 540                         continue;
 541                 }
 542
 543                 outgoing = xmalloc_and_zero(sizeof *outgoing);
 544                 outgoing->name = name;
 545                 list_insert_tail(outgoing_list, outgoing);
 546                 setup_outgoing_connection(outgoing);
 547         }
 548 }