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 #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: %d", 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
  83 static bool bind_to_interface(int sd) {
  84         char *iface;
  85
  86 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  87         struct ifreq ifr;
  88         int status;
  89 #endif /* defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) */
  90
  91         if(!get_config_string (lookup_config (config_tree, "BindToInterface"), &iface))
  92                 return true;
  93
  94 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  95         memset(&ifr, 0, sizeof(ifr));
  96         strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
  97         ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
  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", iface,
 102                                 strerror(errno));
 103                 return false;
 104         }
 105 #else /* if !defined(SOL_SOCKET) || !defined(SO_BINDTODEVICE) */
 106         logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 107 #endif
 108
 109         return true;
 110 }
 111
 112 static bool bind_to_address(connection_t *c) {
 113         char *node;
 114         struct addrinfo *ai_list;
 115         struct addrinfo *ai_ptr;
 116         struct addrinfo ai_hints;
 117         int status;
 118
 119         assert(c != NULL);
 120         assert(c->socket >= 0);
 121
 122         node = NULL;
 123         if(!get_config_string(lookup_config(config_tree, "BindToAddress"),
 124                                 &node))
 125                 return true;
 126
 127         assert(node != NULL);
 128
 129         memset(&ai_hints, 0, sizeof(ai_hints));
 130         ai_hints.ai_family = c->address.sa.sa_family;
 131         /* We're called from `do_outgoing_connection' only. */
 132         ai_hints.ai_socktype = SOCK_STREAM;
 133         ai_hints.ai_protocol = IPPROTO_TCP;
 134
 135         ai_list = NULL;
 136
 137         status = getaddrinfo(node, /* service = */ NULL,
 138                         &ai_hints, &ai_list);
 139         if(status) {
 140                 logger(LOG_WARNING, "Error looking up %s port %s: %s",
 141                                 node, "any", gai_strerror(status));
 142                 free(node);
 143                 return false;
 144         }
 145         assert(ai_list != NULL);
 146
 147         status = -1;
 148         for(ai_ptr = ai_list; ai_ptr != NULL; ai_ptr = ai_ptr->ai_next) {
 149                 status = bind(c->socket,
 150                                 ai_list->ai_addr, ai_list->ai_addrlen);
 151                 if(!status)
 152                         break;
 153         }
 154
 155
 156         if(status) {
 157                 logger(LOG_ERR, "Can't bind to %s/tcp: %s", node, sockstrerror(sockerrno));
 158         } else ifdebug(CONNECTIONS) {
 159                 logger(LOG_DEBUG, "Successfully bound outgoing "
 160                                 "TCP socket to %s", node);
 161         }
 162
 163         free(node);
 164         freeaddrinfo(ai_list);
 165
 166         return status ? false : true;
 167 }
 168
 169 int setup_listen_socket(const sockaddr_t *sa) {
 170         int nfd;
 171         char *addrstr;
 172         int option;
 173         char *iface;
 174
 175         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 176
 177         if(nfd < 0) {
 178                 ifdebug(STATUS) logger(LOG_ERR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
 179                 return -1;
 180         }
 181
 182         /* Optimize TCP settings */
 183
 184         option = 1;
 185         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
 186
 187 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 188         if(sa->sa.sa_family == AF_INET6)
 189                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 190 #endif
 191
 192         if(get_config_string
 193            (lookup_config(config_tree, "BindToInterface"), &iface)) {
 194 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
 195                 struct ifreq ifr;
 196
 197                 memset(&ifr, 0, sizeof ifr);
 198                 strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
 199
 200                 if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof ifr)) {
 201                         closesocket(nfd);
 202                         logger(LOG_ERR, "Can't bind to interface %s: %s", iface,
 203                                    strerror(sockerrno));
 204                         return -1;
 205                 }
 206 #else
 207                 logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 208 #endif
 209         }
 210
 211         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 212                 closesocket(nfd);
 213                 addrstr = sockaddr2hostname(sa);
 214                 logger(LOG_ERR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
 215                 free(addrstr);
 216                 return -1;
 217         }
 218
 219         if(listen(nfd, 3)) {
 220                 closesocket(nfd);
 221                 logger(LOG_ERR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
 222                 return -1;
 223         }
 224
 225         return nfd;
 226 }
 227
 228 int setup_vpn_in_socket(const sockaddr_t *sa) {
 229         int nfd;
 230         char *addrstr;
 231         int option;
 232
 233         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 234
 235         if(nfd < 0) {
 236                 logger(LOG_ERR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
 237                 return -1;
 238         }
 239
 240 #ifdef O_NONBLOCK
 241         {
 242                 int flags = fcntl(nfd, F_GETFL);
 243
 244                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
 245                         closesocket(nfd);
 246                         logger(LOG_ERR, "System call `%s' failed: %s", "fcntl",
 247                                    strerror(errno));
 248                         return -1;
 249                 }
 250         }
 251 #elif defined(WIN32)
 252         {
 253                 unsigned long arg = 1;
 254                 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
 255                         closesocket(nfd);
 256                         logger(LOG_ERR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
 257                         return -1;
 258                 }
 259         }
 260 #endif
 261
 262         option = 1;
 263         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
 264
 265         if(udp_rcvbuf && setsockopt(nfd, SOL_SOCKET, SO_RCVBUF, (void *)&udp_rcvbuf, sizeof(udp_rcvbuf)))
 266                 logger(LOG_WARNING, "Can't set UDP SO_RCVBUF to %i: %s", udp_rcvbuf, strerror(errno));
 267
 268         if(udp_sndbuf && setsockopt(nfd, SOL_SOCKET, SO_SNDBUF, (void *)&udp_sndbuf, sizeof(udp_sndbuf)))
 269                 logger(LOG_WARNING, "Can't set UDP SO_SNDBUF to %i: %s", udp_sndbuf, strerror(errno));
 270
 271 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
 272         if(sa->sa.sa_family == AF_INET6)
 273                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 274 #endif
 275
 276 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
 277 #define IP_DONTFRAGMENT IP_DONTFRAG
 278 #endif
 279
 280 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 281         if(myself->options & OPTION_PMTU_DISCOVERY) {
 282                 option = IP_PMTUDISC_DO;
 283                 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
 284         }
 285 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
 286         if(myself->options & OPTION_PMTU_DISCOVERY) {
 287                 option = 1;
 288                 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
 289         }
 290 #else
 291 #warning No way to disable IPv4 fragmentation
 292 #endif
 293
 294 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 295         if(myself->options & OPTION_PMTU_DISCOVERY) {
 296                 option = IPV6_PMTUDISC_DO;
 297                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
 298         }
 299 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
 300         if(myself->options & OPTION_PMTU_DISCOVERY) {
 301                 option = 1;
 302                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
 303         }
 304 #else
 305 #warning No way to disable IPv6 fragmentation
 306 #endif
 307
 308         if (!bind_to_interface(nfd)) {
 309                 closesocket(nfd);
 310                 return -1;
 311         }
 312
 313         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 314                 closesocket(nfd);
 315                 addrstr = sockaddr2hostname(sa);
 316                 logger(LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
 317                 free(addrstr);
 318                 return -1;
 319         }
 320
 321         return nfd;
 322 } /* int setup_vpn_in_socket */
 323
 324 static void retry_outgoing_handler(int fd, short events, void *data) {
 325         setup_outgoing_connection(data);
 326 }
 327
 328 void retry_outgoing(outgoing_t *outgoing) {
 329         outgoing->timeout += 5;
 330
 331         if(outgoing->timeout > maxtimeout)
 332                 outgoing->timeout = maxtimeout;
 333
 334         timeout_set(&outgoing->ev, retry_outgoing_handler, outgoing);
 335         event_add(&outgoing->ev, &(struct timeval){outgoing->timeout, 0});
 336
 337         ifdebug(CONNECTIONS) logger(LOG_NOTICE,
 338                            "Trying to re-establish outgoing connection in %d seconds",
 339                            outgoing->timeout);
 340 }
 341
 342 void finish_connecting(connection_t *c) {
 343         ifdebug(CONNECTIONS) logger(LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 344
 345         configure_tcp(c);
 346
 347         c->last_ping_time = time(NULL);
 348         c->status.connecting = false;
 349
 350         send_id(c);
 351 }
 352
 353 bool do_outgoing_connection(connection_t *c) {
 354         char *address, *port, *space;
 355         int result;
 356
 357         if(!c->outgoing) {
 358                 logger(LOG_ERR, "do_outgoing_connection() for %s called without c->outgoing", c->name);
 359                 abort();
 360         }
 361
 362 begin:
 363         if(!c->outgoing->ai) {
 364                 if(!c->outgoing->cfg) {
 365                         ifdebug(CONNECTIONS) logger(LOG_ERR, "Could not set up a meta connection to %s",
 366                                            c->name);
 367                         retry_outgoing(c->outgoing);
 368                         c->outgoing = NULL;
 369                         connection_del(c);
 370                         return false;
 371                 }
 372
 373                 get_config_string(c->outgoing->cfg, &address);
 374
 375                 space = strchr(address, ' ');
 376                 if(space) {
 377                         port = xstrdup(space + 1);
 378                         *space = 0;
 379                 } else {
 380                         if(!get_config_string(lookup_config(c->config_tree, "Port"), &port))
 381                                 port = xstrdup("655");
 382                 }
 383
 384                 c->outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 385                 free(address);
 386                 free(port);
 387
 388                 c->outgoing->aip = c->outgoing->ai;
 389                 c->outgoing->cfg = lookup_config_next(c->config_tree, c->outgoing->cfg);
 390         }
 391
 392         if(!c->outgoing->aip) {
 393                 if(c->outgoing->ai)
 394                         freeaddrinfo(c->outgoing->ai);
 395                 c->outgoing->ai = NULL;
 396                 goto begin;
 397         }
 398
 399         memcpy(&c->address, c->outgoing->aip->ai_addr, c->outgoing->aip->ai_addrlen);
 400         c->outgoing->aip = c->outgoing->aip->ai_next;
 401
 402         if(c->hostname)
 403                 free(c->hostname);
 404
 405         c->hostname = sockaddr2hostname(&c->address);
 406
 407         ifdebug(CONNECTIONS) logger(LOG_INFO, "Trying to connect to %s (%s)", c->name,
 408                            c->hostname);
 409
 410         c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 411
 412         if(c->socket == -1) {
 413                 ifdebug(CONNECTIONS) logger(LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
 414                 goto begin;
 415         }
 416
 417 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 418         int option = 1;
 419         if(c->address.sa.sa_family == AF_INET6)
 420                 setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 421 #endif
 422
 423         bind_to_interface(c->socket);
 424         bind_to_address(c);
 425
 426         /* Optimize TCP settings */
 427
 428         configure_tcp(c);
 429
 430         /* Connect */
 431
 432         result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 433
 434         if(result == -1) {
 435                 if(sockinprogress(sockerrno)) {
 436                         c->status.connecting = true;
 437                         return true;
 438                 }
 439
 440                 closesocket(c->socket);
 441
 442                 ifdebug(CONNECTIONS) logger(LOG_ERR, "%s: %s", c->hostname, sockstrerror(sockerrno));
 443
 444                 goto begin;
 445         }
 446
 447         finish_connecting(c);
 448
 449         return true;
 450 }
 451
 452 static void handle_meta_write(int sock, short events, void *data) {
 453         ifdebug(META) logger(LOG_DEBUG, "handle_meta_write() called");
 454
 455         connection_t *c = data;
 456
 457         ssize_t outlen = send(c->socket, c->outbuf.data + c->outbuf.offset, c->outbuf.len - c->outbuf.offset, 0);
 458         if(outlen <= 0) {
 459                 logger(LOG_ERR, "Onoes, outlen = %d (%s)", (int)outlen, strerror(errno));
 460                 terminate_connection(c, c->status.active);
 461                 return;
 462         }
 463
 464         buffer_read(&c->outbuf, outlen);
 465         if(!c->outbuf.len && event_initialized(&c->outevent))
 466                 event_del(&c->outevent);
 467 }
 468
 469 void setup_outgoing_connection(outgoing_t *outgoing) {
 470         connection_t *c;
 471         node_t *n;
 472
 473         if(event_initialized(&outgoing->ev))
 474                 event_del(&outgoing->ev);
 475
 476         n = lookup_node(outgoing->name);
 477
 478         if(n)
 479                 if(n->connection) {
 480                         ifdebug(CONNECTIONS) logger(LOG_INFO, "Already connected to %s", outgoing->name);
 481
 482                         n->connection->outgoing = outgoing;
 483                         return;
 484                 }
 485
 486         c = new_connection();
 487         c->name = xstrdup(outgoing->name);
 488         c->outcipher = myself->connection->outcipher;
 489         c->outdigest = myself->connection->outdigest;
 490         c->outmaclength = myself->connection->outmaclength;
 491         c->outcompression = myself->connection->outcompression;
 492
 493         init_configuration(&c->config_tree);
 494         read_connection_config(c);
 495
 496         outgoing->cfg = lookup_config(c->config_tree, "Address");
 497
 498         if(!outgoing->cfg) {
 499                 logger(LOG_ERR, "No address specified for %s", c->name);
 500                 free_connection(c);
 501                 return;
 502         }
 503
 504         c->outgoing = outgoing;
 505         c->last_ping_time = time(NULL);
 506
 507         connection_add(c);
 508
 509         if (do_outgoing_connection(c)) {
 510                 event_set(&c->inevent, c->socket, EV_READ | EV_PERSIST, handle_meta_connection_data, c);
 511                 event_set(&c->outevent, c->socket, EV_WRITE | EV_PERSIST, handle_meta_write, c);
 512                 event_add(&c->inevent, NULL);
 513         }
 514 }
 515
 516 /*
 517   accept a new tcp connect and create a
 518   new connection
 519 */
 520 void handle_new_meta_connection(int sock, short events, void *data) {
 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;
 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 = time(NULL);
 546
 547         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection from %s", c->hostname);
 548
 549         event_set(&c->inevent, c->socket, EV_READ | EV_PERSIST, handle_meta_connection_data, c);
 550         event_set(&c->outevent, c->socket, EV_WRITE | EV_PERSIST, handle_meta_write, c);
 551         event_add(&c->inevent, NULL);
 552
 553         configure_tcp(c);
 554
 555         connection_add(c);
 556
 557         c->allow_request = ID;
 558         send_id(c);
 559 }
 560
 561 static void free_outgoing(outgoing_t *outgoing) {
 562         if(outgoing->ai)
 563                 freeaddrinfo(outgoing->ai);
 564
 565         if(outgoing->name)
 566                 free(outgoing->name);
 567
 568         free(outgoing);
 569 }
 570
 571 void try_outgoing_connections(void) {
 572         static config_t *cfg = NULL;
 573         char *name;
 574         outgoing_t *outgoing;
 575
 576         outgoing_list = list_alloc((list_action_t)free_outgoing);
 577
 578         for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 579                 get_config_string(cfg, &name);
 580
 581                 if(!check_id(name)) {
 582                         logger(LOG_ERR,
 583                                    "Invalid name for outgoing connection in %s line %d",
 584                                    cfg->file, cfg->line);
 585                         free(name);
 586                         continue;
 587                 }
 588
 589                 outgoing = xmalloc_and_zero(sizeof *outgoing);
 590                 outgoing->name = name;
 591                 list_insert_tail(outgoing_list, outgoing);
 592                 setup_outgoing_connection(outgoing);
 593         }
 594 }