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                   2000-2010 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(int fd, short events, 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         timeout_set(&outgoing->ev, retry_outgoing_handler, outgoing);
 299         event_add(&outgoing->ev, &(struct timeval){outgoing->timeout, 0});
 300
 301         ifdebug(CONNECTIONS) logger(LOG_NOTICE,
 302                            "Trying to re-establish outgoing connection in %d seconds",
 303                            outgoing->timeout);
 304 }
 305
 306 void finish_connecting(connection_t *c) {
 307         ifdebug(CONNECTIONS) logger(LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 308
 309         configure_tcp(c);
 310
 311         c->last_ping_time = time(NULL);
 312         c->status.connecting = false;
 313
 314         send_id(c);
 315 }
 316
 317 void do_outgoing_connection(connection_t *c) {
 318         char *address, *port, *space;
 319         int result;
 320
 321         if(!c->outgoing) {
 322                 logger(LOG_ERR, "do_outgoing_connection() for %s called without c->outgoing", c->name);
 323                 abort();
 324         }
 325
 326 begin:
 327         if(!c->outgoing->ai) {
 328                 if(!c->outgoing->cfg) {
 329                         ifdebug(CONNECTIONS) logger(LOG_ERR, "Could not set up a meta connection to %s",
 330                                            c->name);
 331                         retry_outgoing(c->outgoing);
 332                         c->outgoing = NULL;
 333                         connection_del(c);
 334                         return;
 335                 }
 336
 337                 get_config_string(c->outgoing->cfg, &address);
 338
 339                 space = strchr(address, ' ');
 340                 if(space) {
 341                         port = xstrdup(space + 1);
 342                         *space = 0;
 343                 } else {
 344                         if(!get_config_string(lookup_config(c->config_tree, "Port"), &port))
 345                                 port = xstrdup("655");
 346                 }
 347
 348                 c->outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 349                 free(address);
 350                 free(port);
 351
 352                 c->outgoing->aip = c->outgoing->ai;
 353                 c->outgoing->cfg = lookup_config_next(c->config_tree, c->outgoing->cfg);
 354         }
 355
 356         if(!c->outgoing->aip) {
 357                 if(c->outgoing->ai)
 358                         freeaddrinfo(c->outgoing->ai);
 359                 c->outgoing->ai = NULL;
 360                 goto begin;
 361         }
 362
 363         memcpy(&c->address, c->outgoing->aip->ai_addr, c->outgoing->aip->ai_addrlen);
 364         c->outgoing->aip = c->outgoing->aip->ai_next;
 365
 366         if(c->hostname)
 367                 free(c->hostname);
 368
 369         c->hostname = sockaddr2hostname(&c->address);
 370
 371         ifdebug(CONNECTIONS) logger(LOG_INFO, "Trying to connect to %s (%s)", c->name,
 372                            c->hostname);
 373
 374         c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 375
 376         if(c->socket == -1) {
 377                 ifdebug(CONNECTIONS) logger(LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
 378                 goto begin;
 379         }
 380
 381 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 382         int option = 1;
 383         if(c->address.sa.sa_family == AF_INET6)
 384                 setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 385 #endif
 386
 387         bind_to_interface(c->socket);
 388         bind_to_address(c);
 389
 390         /* Optimize TCP settings */
 391
 392         configure_tcp(c);
 393
 394         /* Connect */
 395
 396         result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 397
 398         if(result == -1) {
 399                 if(sockinprogress(sockerrno)) {
 400                         c->status.connecting = true;
 401                         return;
 402                 }
 403
 404                 closesocket(c->socket);
 405
 406                 ifdebug(CONNECTIONS) logger(LOG_ERR, "%s: %s", c->hostname, sockstrerror(sockerrno));
 407
 408                 goto begin;
 409         }
 410
 411         finish_connecting(c);
 412
 413         return;
 414 }
 415
 416 void handle_meta_read(struct bufferevent *event, void *data) {
 417         logger(LOG_ERR, "handle_meta_read() called");
 418         abort();
 419 }
 420
 421 void handle_meta_write(struct bufferevent *event, void *data) {
 422         ifdebug(META) logger(LOG_DEBUG, "handle_meta_write() called");
 423 }
 424
 425 void handle_meta_connection_error(struct bufferevent *event, short what, void *data) {
 426         connection_t *c = data;
 427         logger(LOG_ERR, "handle_meta_connection_error() called: %d: %s", what, strerror(errno));
 428         terminate_connection(c, c->status.active);
 429 }
 430
 431 void setup_outgoing_connection(outgoing_t *outgoing) {
 432         connection_t *c;
 433         node_t *n;
 434
 435         event_del(&outgoing->ev);
 436
 437         n = lookup_node(outgoing->name);
 438
 439         if(n)
 440                 if(n->connection) {
 441                         ifdebug(CONNECTIONS) logger(LOG_INFO, "Already connected to %s", outgoing->name);
 442
 443                         n->connection->outgoing = outgoing;
 444                         return;
 445                 }
 446
 447         c = new_connection();
 448         c->name = xstrdup(outgoing->name);
 449         c->outcipher = myself->connection->outcipher;
 450         c->outdigest = myself->connection->outdigest;
 451         c->outmaclength = myself->connection->outmaclength;
 452         c->outcompression = myself->connection->outcompression;
 453
 454         init_configuration(&c->config_tree);
 455         read_connection_config(c);
 456
 457         outgoing->cfg = lookup_config(c->config_tree, "Address");
 458
 459         if(!outgoing->cfg) {
 460                 logger(LOG_ERR, "No address specified for %s", c->name);
 461                 free_connection(c);
 462                 return;
 463         }
 464
 465         c->outgoing = outgoing;
 466         c->last_ping_time = time(NULL);
 467
 468         connection_add(c);
 469
 470         do_outgoing_connection(c);
 471
 472         c->buffer = bufferevent_new(c->socket, handle_meta_read, handle_meta_write, handle_meta_connection_error, c);
 473         if(!c->buffer) {
 474                 logger(LOG_ERR, "bufferevent_new() failed: %s", strerror(errno));
 475                 abort();
 476         }
 477         bufferevent_disable(c->buffer, EV_READ);
 478
 479         if(!thread_create(&c->thread, handle_meta_connection_data, c)) {
 480                 logger(LOG_ERR, "create_thread() failed: %s", strerror(errno));
 481                 abort();
 482         }
 483 }
 484
 485 /*
 486   accept a new tcp connect and create a
 487   new connection
 488 */
 489 void handle_new_meta_connection(int sock, short events, void *data) {
 490         connection_t *c;
 491         sockaddr_t sa;
 492         int fd;
 493         socklen_t len = sizeof sa;
 494
 495         fd = accept(sock, &sa.sa, &len);
 496
 497         if(fd < 0) {
 498                 logger(LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 499                 return;
 500         }
 501
 502         sockaddrunmap(&sa);
 503
 504         c = new_connection();
 505         c->name = xstrdup("<unknown>");
 506         c->outcipher = myself->connection->outcipher;
 507         c->outdigest = myself->connection->outdigest;
 508         c->outmaclength = myself->connection->outmaclength;
 509         c->outcompression = myself->connection->outcompression;
 510
 511         c->address = sa;
 512         c->hostname = sockaddr2hostname(&sa);
 513         c->socket = fd;
 514         c->last_ping_time = time(NULL);
 515
 516         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection from %s", c->hostname);
 517
 518         c->buffer = bufferevent_new(c->socket, NULL, handle_meta_write, handle_meta_connection_error, c);
 519         if(!c->buffer) {
 520                 logger(LOG_ERR, "bufferevent_new() failed: %s", strerror(errno));
 521                 abort();
 522         }
 523         bufferevent_disable(c->buffer, EV_READ);
 524
 525         configure_tcp(c);
 526
 527         connection_add(c);
 528
 529         c->allow_request = ID;
 530         send_id(c);
 531
 532         if(!thread_create(&c->thread, handle_meta_connection_data, c)) {
 533                 logger(LOG_ERR, "create_thread() failed: %s", strerror(errno));
 534                 abort();
 535         }
 536 }
 537
 538 void free_outgoing(outgoing_t *outgoing) {
 539         if(outgoing->ai)
 540                 freeaddrinfo(outgoing->ai);
 541
 542         if(outgoing->name)
 543                 free(outgoing->name);
 544
 545         free(outgoing);
 546 }
 547
 548 void try_outgoing_connections(void) {
 549         static config_t *cfg = NULL;
 550         char *name;
 551         outgoing_t *outgoing;
 552
 553         outgoing_list = list_alloc((list_action_t)free_outgoing);
 554
 555         for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 556                 get_config_string(cfg, &name);
 557
 558                 if(!check_id(name)) {
 559                         logger(LOG_ERR,
 560                                    "Invalid name for outgoing connection in %s line %d",
 561                                    cfg->file, cfg->line);
 562                         free(name);
 563                         continue;
 564                 }
 565
 566                 outgoing = xmalloc_and_zero(sizeof *outgoing);
 567                 outgoing->name = name;
 568                 list_insert_tail(outgoing_list, outgoing);
 569                 setup_outgoing_connection(outgoing);
 570         }
 571 }