src/net_socket.c

   1 /*
   2     net_socket.c -- Handle various kinds of sockets.
   3     Copyright (C) 1998-2005 Ivo Timmermans,
   4                   2000-2009 Guus Sliepen <guus@tinc-vpn.org>
   5                   2009      Florian Forster <octo@verplant.org>
   6
   7     This program is free software; you can redistribute it and/or modify
   8     it under the terms of the GNU General Public License as published by
   9     the Free Software Foundation; either version 2 of the License, or
  10     (at your option) any later version.
  11
  12     This program is distributed in the hope that it will be useful,
  13     but WITHOUT ANY WARRANTY; without even the implied warranty of
  14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU General Public License along
  18     with this program; if not, write to the Free Software Foundation, Inc.,
  19     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20 */
  21
  22 #include "system.h"
  23
  24 #include "avl_tree.h"
  25 #include "conf.h"
  26 #include "connection.h"
  27 #include "event.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 #ifdef WSAEINPROGRESS
  39 #define EINPROGRESS WSAEINPROGRESS
  40 #endif
  41
  42 /* Needed on Mac OS/X */
  43 #ifndef SOL_TCP
  44 #define SOL_TCP IPPROTO_TCP
  45 #endif
  46
  47 int addressfamily = AF_UNSPEC;
  48 int maxtimeout = 900;
  49 int seconds_till_retry = 5;
  50
  51 listen_socket_t listen_socket[MAXSOCKETS];
  52 int listen_sockets;
  53 list_t *outgoing_list = NULL;
  54
  55 /* Setup sockets */
  56
  57 static void configure_tcp(connection_t *c) {
  58         int option;
  59
  60 #ifdef O_NONBLOCK
  61         int flags = fcntl(c->socket, F_GETFL);
  62
  63         if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
  64                 logger(LOG_ERR, _("fcntl for %s: %s"), c->hostname, strerror(errno));
  65         }
  66 #elif defined(WIN32)
  67         unsigned long arg = 1;
  68
  69         if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
  70                 logger(LOG_ERR, _("ioctlsocket for %s: WSA error %d"), c->hostname, WSAGetLastError());
  71         }
  72 #endif
  73
  74 #if defined(SOL_TCP) && defined(TCP_NODELAY)
  75         option = 1;
  76         setsockopt(c->socket, SOL_TCP, TCP_NODELAY, &option, sizeof(option));
  77 #endif
  78
  79 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
  80         option = IPTOS_LOWDELAY;
  81         setsockopt(c->socket, SOL_IP, IP_TOS, &option, sizeof(option));
  82 #endif
  83 }
  84
  85 static bool bind_to_interface(int sd) {
  86         char *iface;
  87
  88 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  89         struct ifreq ifr;
  90         int status;
  91 #endif /* defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) */
  92
  93         if(!get_config_string (lookup_config (config_tree, "BindToInterface"), &iface))
  94                 return true;
  95
  96 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  97         memset(&ifr, 0, sizeof(ifr));
  98         strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
  99         ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
 100
 101         status = setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr));
 102         if(status) {
 103                 logger(LOG_ERR, _("Can't bind to interface %s: %s"), iface,
 104                                 strerror(errno));
 105                 return false;
 106         }
 107 #else /* if !defined(SOL_SOCKET) || !defined(SO_BINDTODEVICE) */
 108         logger(LOG_WARNING, _("%s not supported on this platform"), "BindToInterface");
 109 #endif
 110
 111         return true;
 112 }
 113
 114 static bool bind_to_address(connection_t *c) {
 115         char *node;
 116         struct addrinfo *ai_list;
 117         struct addrinfo *ai_ptr;
 118         struct addrinfo ai_hints;
 119         int status;
 120
 121         assert(c != NULL);
 122         assert(c->socket >= 0);
 123
 124         node = NULL;
 125         if(!get_config_string(lookup_config(config_tree, "BindToAddress"),
 126                                 &node))
 127                 return true;
 128
 129         assert(node != NULL);
 130
 131         memset(&ai_hints, 0, sizeof(ai_hints));
 132         ai_hints.ai_family = c->address.sa.sa_family;
 133         /* We're called from `do_outgoing_connection' only. */
 134         ai_hints.ai_socktype = SOCK_STREAM;
 135         ai_hints.ai_protocol = IPPROTO_TCP;
 136
 137         ai_list = NULL;
 138
 139         status = getaddrinfo(node, /* service = */ NULL,
 140                         &ai_hints, &ai_list);
 141         if(status) {
 142                 free(node);
 143                 logger(LOG_WARNING, _("Error looking up %s port %s: %s"),
 144                                 node, _("any"), gai_strerror(status));
 145                 return false;
 146         }
 147         assert(ai_list != NULL);
 148
 149         status = -1;
 150         for(ai_ptr = ai_list; ai_ptr != NULL; ai_ptr = ai_ptr->ai_next) {
 151                 status = bind(c->socket,
 152                                 ai_list->ai_addr, ai_list->ai_addrlen);
 153                 if(!status)
 154                         break;
 155         }
 156
 157
 158         if(status) {
 159                 logger(LOG_ERR, _("Can't bind to %s/tcp: %s"), node,
 160                                 strerror(errno));
 161         } else ifdebug(CONNECTIONS) {
 162                 logger(LOG_DEBUG, "Successfully bound outgoing "
 163                                 "TCP socket to %s", node);
 164         }
 165
 166         free(node);
 167         freeaddrinfo(ai_list);
 168
 169         return status ? false : true;
 170 }
 171
 172 int setup_listen_socket(const sockaddr_t *sa) {
 173         int nfd;
 174         char *addrstr;
 175         int option;
 176         char *iface;
 177
 178         cp();
 179
 180         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 181
 182         if(nfd < 0) {
 183                 ifdebug(STATUS) logger(LOG_ERR, _("Creating metasocket failed: %s"), strerror(errno));
 184                 return -1;
 185         }
 186
 187         /* Optimize TCP settings */
 188
 189         option = 1;
 190         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &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, &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, &ifr, sizeof(ifr))) {
 206                         closesocket(nfd);
 207                         logger(LOG_ERR, _("Can't bind to interface %s: %s"), iface,
 208                                    strerror(errno));
 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,
 220                            strerror(errno));
 221                 free(addrstr);
 222                 return -1;
 223         }
 224
 225         if(listen(nfd, 3)) {
 226                 closesocket(nfd);
 227                 logger(LOG_ERR, _("System call `%s' failed: %s"), "listen",
 228                            strerror(errno));
 229                 return -1;
 230         }
 231
 232         return nfd;
 233 }
 234
 235 int setup_vpn_in_socket(const sockaddr_t *sa) {
 236         int nfd;
 237         char *addrstr;
 238         int option;
 239
 240         cp();
 241
 242         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 243
 244         if(nfd < 0) {
 245                 logger(LOG_ERR, _("Creating UDP socket failed: %s"), strerror(errno));
 246                 return -1;
 247         }
 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: WSA error %d"), "ioctlsocket",
 266                                 WSAGetLastError());
 267                         return -1;
 268                 }
 269         }
 270 #endif
 271
 272         option = 1;
 273         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option));
 274
 275 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 276         if(sa->sa.sa_family == AF_INET6)
 277                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, &option, sizeof option);
 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, &option, sizeof(option));
 284         }
 285 #endif
 286
 287 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 288         if(myself->options & OPTION_PMTU_DISCOVERY) {
 289                 option = IPV6_PMTUDISC_DO;
 290                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, &option, sizeof(option));
 291         }
 292 #endif
 293
 294         if (!bind_to_interface(nfd)) {
 295                 closesocket(nfd);
 296                 return -1;
 297         }
 298
 299         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 300                 closesocket(nfd);
 301                 addrstr = sockaddr2hostname(sa);
 302                 logger(LOG_ERR, _("Can't bind to %s/udp: %s"), addrstr,
 303                            strerror(errno));
 304                 free(addrstr);
 305                 return -1;
 306         }
 307
 308         return nfd;
 309 } /* int setup_vpn_in_socket */
 310
 311 void retry_outgoing(outgoing_t *outgoing) {
 312         event_t *event;
 313
 314         cp();
 315
 316         outgoing->timeout += 5;
 317
 318         if(outgoing->timeout > maxtimeout)
 319                 outgoing->timeout = maxtimeout;
 320
 321         event = new_event();
 322         event->handler = (event_handler_t) setup_outgoing_connection;
 323         event->time = now + outgoing->timeout;
 324         event->data = outgoing;
 325         event_add(event);
 326
 327         ifdebug(CONNECTIONS) logger(LOG_NOTICE,
 328                            _("Trying to re-establish outgoing connection in %d seconds"),
 329                            outgoing->timeout);
 330 }
 331
 332 void finish_connecting(connection_t *c) {
 333         cp();
 334
 335         ifdebug(CONNECTIONS) logger(LOG_INFO, _("Connected to %s (%s)"), c->name, c->hostname);
 336
 337         configure_tcp(c);
 338
 339         c->last_ping_time = now;
 340
 341         send_id(c);
 342 }
 343
 344 void do_outgoing_connection(connection_t *c) {
 345         char *address, *port;
 346         int result;
 347
 348         cp();
 349
 350 begin:
 351         if(!c->outgoing->ai) {
 352                 if(!c->outgoing->cfg) {
 353                         ifdebug(CONNECTIONS) logger(LOG_ERR, _("Could not set up a meta connection to %s"),
 354                                            c->name);
 355                         c->status.remove = true;
 356                         retry_outgoing(c->outgoing);
 357                         return;
 358                 }
 359
 360                 get_config_string(c->outgoing->cfg, &address);
 361
 362                 if(!get_config_string(lookup_config(c->config_tree, "Port"), &port))
 363                         xasprintf(&port, "655");
 364
 365                 c->outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 366                 free(address);
 367                 free(port);
 368
 369                 c->outgoing->aip = c->outgoing->ai;
 370                 c->outgoing->cfg = lookup_config_next(c->config_tree, c->outgoing->cfg);
 371         }
 372
 373         if(!c->outgoing->aip) {
 374                 if(c->outgoing->ai)
 375                         freeaddrinfo(c->outgoing->ai);
 376                 c->outgoing->ai = NULL;
 377                 goto begin;
 378         }
 379
 380         memcpy(&c->address, c->outgoing->aip->ai_addr, c->outgoing->aip->ai_addrlen);
 381         c->outgoing->aip = c->outgoing->aip->ai_next;
 382
 383         if(c->hostname)
 384                 free(c->hostname);
 385
 386         c->hostname = sockaddr2hostname(&c->address);
 387
 388         ifdebug(CONNECTIONS) logger(LOG_INFO, _("Trying to connect to %s (%s)"), c->name,
 389                            c->hostname);
 390
 391         c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 392
 393         if(c->socket == -1) {
 394                 ifdebug(CONNECTIONS) logger(LOG_ERR, _("Creating socket for %s failed: %s"), c->hostname,
 395                                    strerror(errno));
 396
 397                 goto begin;
 398         }
 399
 400 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 401         int option = 1;
 402         if(c->address.sa.sa_family == AF_INET6)
 403                 setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, &option, sizeof option);
 404 #endif
 405
 406         bind_to_interface(c->socket);
 407         bind_to_address(c);
 408
 409         /* Optimize TCP settings */
 410
 411         configure_tcp(c);
 412
 413         /* Connect */
 414
 415         result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 416
 417         if(result == -1) {
 418                 if(errno == EINPROGRESS
 419 #if defined(WIN32) && !defined(O_NONBLOCK)
 420                    || WSAGetLastError() == WSAEWOULDBLOCK
 421 #endif
 422                 ) {
 423                         c->status.connecting = true;
 424                         return;
 425                 }
 426
 427                 closesocket(c->socket);
 428
 429                 ifdebug(CONNECTIONS) logger(LOG_ERR, _("%s: %s"), c->hostname, strerror(errno));
 430
 431                 goto begin;
 432         }
 433
 434         finish_connecting(c);
 435
 436         return;
 437 }
 438
 439 void setup_outgoing_connection(outgoing_t *outgoing) {
 440         connection_t *c;
 441         node_t *n;
 442
 443         cp();
 444
 445         n = lookup_node(outgoing->name);
 446
 447         if(n)
 448                 if(n->connection) {
 449                         ifdebug(CONNECTIONS) logger(LOG_INFO, _("Already connected to %s"), outgoing->name);
 450
 451                         n->connection->outgoing = outgoing;
 452                         return;
 453                 }
 454
 455         c = new_connection();
 456         c->name = xstrdup(outgoing->name);
 457         c->outcipher = myself->connection->outcipher;
 458         c->outdigest = myself->connection->outdigest;
 459         c->outmaclength = myself->connection->outmaclength;
 460         c->outcompression = myself->connection->outcompression;
 461
 462         init_configuration(&c->config_tree);
 463         read_connection_config(c);
 464
 465         outgoing->cfg = lookup_config(c->config_tree, "Address");
 466
 467         if(!outgoing->cfg) {
 468                 logger(LOG_ERR, _("No address specified for %s"), c->name);
 469                 free_connection(c);
 470                 return;
 471         }
 472
 473         c->outgoing = outgoing;
 474         c->last_ping_time = now;
 475
 476         connection_add(c);
 477
 478         do_outgoing_connection(c);
 479 }
 480
 481 /*
 482   accept a new tcp connect and create a
 483   new connection
 484 */
 485 bool handle_new_meta_connection(int sock) {
 486         connection_t *c;
 487         sockaddr_t sa;
 488         int fd;
 489         socklen_t len = sizeof(sa);
 490
 491         cp();
 492
 493         fd = accept(sock, &sa.sa, &len);
 494
 495         if(fd < 0) {
 496                 logger(LOG_ERR, _("Accepting a new connection failed: %s"),
 497                            strerror(errno));
 498                 return false;
 499         }
 500
 501         sockaddrunmap(&sa);
 502
 503         c = new_connection();
 504         c->name = xstrdup("<unknown>");
 505         c->outcipher = myself->connection->outcipher;
 506         c->outdigest = myself->connection->outdigest;
 507         c->outmaclength = myself->connection->outmaclength;
 508         c->outcompression = myself->connection->outcompression;
 509
 510         c->address = sa;
 511         c->hostname = sockaddr2hostname(&sa);
 512         c->socket = fd;
 513         c->last_ping_time = now;
 514
 515         ifdebug(CONNECTIONS) logger(LOG_NOTICE, _("Connection from %s"), c->hostname);
 516
 517         configure_tcp(c);
 518
 519         connection_add(c);
 520
 521         c->allow_request = ID;
 522         send_id(c);
 523
 524         return true;
 525 }
 526
 527 void free_outgoing(outgoing_t *outgoing) {
 528         if(outgoing->ai)
 529                 freeaddrinfo(outgoing->ai);
 530
 531         if(outgoing->name)
 532                 free(outgoing->name);
 533
 534         free(outgoing);
 535 }
 536
 537 void try_outgoing_connections(void) {
 538         static config_t *cfg = NULL;
 539         char *name;
 540         outgoing_t *outgoing;
 541         connection_t *c;
 542         avl_node_t *node;
 543
 544         cp();
 545
 546         if(outgoing_list) {
 547                 for(node = connection_tree->head; node; node = node->next) {
 548                         c = node->data;
 549                         c->outgoing = NULL;
 550                 }
 551
 552                 list_delete_list(outgoing_list);
 553         }
 554
 555         outgoing_list = list_alloc((list_action_t)free_outgoing);
 556
 557         for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 558                 get_config_string(cfg, &name);
 559
 560                 if(!check_id(name)) {
 561                         logger(LOG_ERR,
 562                                    _("Invalid name for outgoing connection in %s line %d"),
 563                                    cfg->file, cfg->line);
 564                         free(name);
 565                         continue;
 566                 }
 567
 568                 outgoing = xmalloc_and_zero(sizeof(*outgoing));
 569                 outgoing->name = name;
 570                 list_insert_tail(outgoing_list, outgoing);
 571                 setup_outgoing_connection(outgoing);
 572         }
 573 }