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                   2000-2009 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 #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         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 179
 180         if(nfd < 0) {
 181                 ifdebug(STATUS) logger(LOG_ERR, "Creating metasocket failed: %s", strerror(errno));
 182                 return -1;
 183         }
 184
 185         /* Optimize TCP settings */
 186
 187         option = 1;
 188         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof option);
 189
 190 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 191         if(sa->sa.sa_family == AF_INET6)
 192                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, &option, sizeof option);
 193 #endif
 194
 195         if(get_config_string
 196            (lookup_config(config_tree, "BindToInterface"), &iface)) {
 197 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
 198                 struct ifreq ifr;
 199
 200                 memset(&ifr, 0, sizeof ifr);
 201                 strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
 202
 203                 if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof ifr)) {
 204                         closesocket(nfd);
 205                         logger(LOG_ERR, "Can't bind to interface %s: %s", iface,
 206                                    strerror(errno));
 207                         return -1;
 208                 }
 209 #else
 210                 logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 211 #endif
 212         }
 213
 214         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 215                 closesocket(nfd);
 216                 addrstr = sockaddr2hostname(sa);
 217                 logger(LOG_ERR, "Can't bind to %s/tcp: %s", addrstr,
 218                            strerror(errno));
 219                 free(addrstr);
 220                 return -1;
 221         }
 222
 223         if(listen(nfd, 3)) {
 224                 closesocket(nfd);
 225                 logger(LOG_ERR, "System call `%s' failed: %s", "listen",
 226                            strerror(errno));
 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", strerror(errno));
 242                 return -1;
 243         }
 244
 245 #ifdef O_NONBLOCK
 246         {
 247                 int flags = fcntl(nfd, F_GETFL);
 248
 249                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
 250                         closesocket(nfd);
 251                         logger(LOG_ERR, "System call `%s' failed: %s", "fcntl",
 252                                    strerror(errno));
 253                         return -1;
 254                 }
 255         }
 256 #elif defined(WIN32)
 257         {
 258                 unsigned long arg = 1;
 259                 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
 260                         closesocket(nfd);
 261                         logger(LOG_ERR, "Call to `%s' failed: WSA error %d", "ioctlsocket",
 262                                 WSAGetLastError());
 263                         return -1;
 264                 }
 265         }
 266 #endif
 267
 268         option = 1;
 269         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof option);
 270
 271 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 272         if(sa->sa.sa_family == AF_INET6)
 273                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, &option, sizeof option);
 274 #endif
 275
 276 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 277         if(myself->options & OPTION_PMTU_DISCOVERY) {
 278                 option = IP_PMTUDISC_DO;
 279                 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, &option, sizeof(option));
 280         }
 281 #endif
 282
 283 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 284         if(myself->options & OPTION_PMTU_DISCOVERY) {
 285                 option = IPV6_PMTUDISC_DO;
 286                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, &option, sizeof(option));
 287         }
 288 #endif
 289
 290         if (!bind_to_interface(nfd)) {
 291                 closesocket(nfd);
 292                 return -1;
 293         }
 294
 295         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 296                 closesocket(nfd);
 297                 addrstr = sockaddr2hostname(sa);
 298                 logger(LOG_ERR, "Can't bind to %s/udp: %s", addrstr,
 299                            strerror(errno));
 300                 free(addrstr);
 301                 return -1;
 302         }
 303
 304         return nfd;
 305 } /* int setup_vpn_in_socket */
 306
 307 static void retry_outgoing_handler(int fd, short events, void *data) {
 308         setup_outgoing_connection(data);
 309 }
 310
 311 void retry_outgoing(outgoing_t *outgoing) {
 312         outgoing->timeout += 5;
 313
 314         if(outgoing->timeout > maxtimeout)
 315                 outgoing->timeout = maxtimeout;
 316
 317         timeout_set(&outgoing->ev, retry_outgoing_handler, outgoing);
 318         event_add(&outgoing->ev, &(struct timeval){outgoing->timeout, 0});
 319
 320         ifdebug(CONNECTIONS) logger(LOG_NOTICE,
 321                            "Trying to re-establish outgoing connection in %d seconds",
 322                            outgoing->timeout);
 323 }
 324
 325 void finish_connecting(connection_t *c) {
 326         ifdebug(CONNECTIONS) logger(LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 327
 328         configure_tcp(c);
 329
 330         c->last_ping_time = time(NULL);
 331         c->status.connecting = false;
 332
 333         send_id(c);
 334 }
 335
 336 void do_outgoing_connection(connection_t *c) {
 337         char *address, *port;
 338         int result;
 339
 340 begin:
 341         if(!c->outgoing->ai) {
 342                 if(!c->outgoing->cfg) {
 343                         ifdebug(CONNECTIONS) logger(LOG_ERR, "Could not set up a meta connection to %s",
 344                                            c->name);
 345                         retry_outgoing(c->outgoing);
 346                         c->outgoing = NULL;
 347                         connection_del(c);
 348                         return;
 349                 }
 350
 351                 get_config_string(c->outgoing->cfg, &address);
 352
 353                 if(!get_config_string(lookup_config(c->config_tree, "Port"), &port))
 354                         xasprintf(&port, "655");
 355
 356                 c->outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 357                 free(address);
 358                 free(port);
 359
 360                 c->outgoing->aip = c->outgoing->ai;
 361                 c->outgoing->cfg = lookup_config_next(c->config_tree, c->outgoing->cfg);
 362         }
 363
 364         if(!c->outgoing->aip) {
 365                 if(c->outgoing->ai)
 366                         freeaddrinfo(c->outgoing->ai);
 367                 c->outgoing->ai = NULL;
 368                 goto begin;
 369         }
 370
 371         memcpy(&c->address, c->outgoing->aip->ai_addr, c->outgoing->aip->ai_addrlen);
 372         c->outgoing->aip = c->outgoing->aip->ai_next;
 373
 374         if(c->hostname)
 375                 free(c->hostname);
 376
 377         c->hostname = sockaddr2hostname(&c->address);
 378
 379         ifdebug(CONNECTIONS) logger(LOG_INFO, "Trying to connect to %s (%s)", c->name,
 380                            c->hostname);
 381
 382         c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 383
 384         if(c->socket == -1) {
 385                 ifdebug(CONNECTIONS) logger(LOG_ERR, "Creating socket for %s failed: %s", c->hostname,
 386                                    strerror(errno));
 387
 388                 goto begin;
 389         }
 390
 391 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 392         int option = 1;
 393         if(c->address.sa.sa_family == AF_INET6)
 394                 setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, &option, sizeof option);
 395 #endif
 396
 397         bind_to_interface(c->socket);
 398         bind_to_address(c);
 399
 400         /* Optimize TCP settings */
 401
 402         configure_tcp(c);
 403
 404         /* Connect */
 405
 406         result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 407
 408         if(result == -1) {
 409                 if(errno == EINPROGRESS
 410 #if defined(WIN32) && !defined(O_NONBLOCK)
 411                    || WSAGetLastError() == WSAEWOULDBLOCK
 412 #endif
 413                 ) {
 414                         c->status.connecting = true;
 415                         return;
 416                 }
 417
 418                 closesocket(c->socket);
 419
 420                 ifdebug(CONNECTIONS) logger(LOG_ERR, "%s: %s", c->hostname, strerror(errno));
 421
 422                 goto begin;
 423         }
 424
 425         finish_connecting(c);
 426
 427         return;
 428 }
 429
 430 void handle_meta_read(struct bufferevent *event, void *data) {
 431         logger(LOG_EMERG, "handle_meta_read() called");
 432         abort();
 433 }
 434
 435 void handle_meta_write(struct bufferevent *event, void *data) {
 436         ifdebug(META) logger(LOG_DEBUG, "handle_meta_write() called");
 437 }
 438
 439 void handle_meta_connection_error(struct bufferevent *event, short what, void *data) {
 440         connection_t *c = data;
 441         logger(LOG_EMERG, "handle_meta_connection_error() called: %d: %s", what, strerror(errno));
 442         terminate_connection(c, c->status.active);
 443 }
 444
 445 void setup_outgoing_connection(outgoing_t *outgoing) {
 446         connection_t *c;
 447         node_t *n;
 448
 449         n = lookup_node(outgoing->name);
 450
 451         if(n)
 452                 if(n->connection) {
 453                         ifdebug(CONNECTIONS) logger(LOG_INFO, "Already connected to %s", outgoing->name);
 454
 455                         n->connection->outgoing = outgoing;
 456                         return;
 457                 }
 458
 459         c = new_connection();
 460         c->name = xstrdup(outgoing->name);
 461         c->outcipher = myself->connection->outcipher;
 462         c->outdigest = myself->connection->outdigest;
 463         c->outmaclength = myself->connection->outmaclength;
 464         c->outcompression = myself->connection->outcompression;
 465
 466         init_configuration(&c->config_tree);
 467         read_connection_config(c);
 468
 469         outgoing->cfg = lookup_config(c->config_tree, "Address");
 470
 471         if(!outgoing->cfg) {
 472                 logger(LOG_ERR, "No address specified for %s", c->name);
 473                 free_connection(c);
 474                 return;
 475         }
 476
 477         c->outgoing = outgoing;
 478         c->last_ping_time = time(NULL);
 479
 480         connection_add(c);
 481
 482         do_outgoing_connection(c);
 483
 484         event_set(&c->inevent, c->socket, EV_READ | EV_PERSIST, handle_meta_connection_data, c);
 485         event_add(&c->inevent, NULL);
 486         c->buffer = bufferevent_new(c->socket, handle_meta_read, handle_meta_write, handle_meta_connection_error, c);
 487         if(!c->buffer) {
 488                 logger(LOG_EMERG, "bufferevent_new() failed: %s", strerror(errno));
 489                 abort();
 490         }
 491         bufferevent_disable(c->buffer, EV_READ);
 492 }
 493
 494 /*
 495   accept a new tcp connect and create a
 496   new connection
 497 */
 498 void handle_new_meta_connection(int sock, short events, void *data) {
 499         connection_t *c;
 500         sockaddr_t sa;
 501         int fd;
 502         socklen_t len = sizeof sa;
 503
 504         fd = accept(sock, &sa.sa, &len);
 505
 506         if(fd < 0) {
 507                 logger(LOG_ERR, "Accepting a new connection failed: %s", strerror(errno));
 508                 return;
 509         }
 510
 511         sockaddrunmap(&sa);
 512
 513         c = new_connection();
 514         c->name = xstrdup("<unknown>");
 515         c->outcipher = myself->connection->outcipher;
 516         c->outdigest = myself->connection->outdigest;
 517         c->outmaclength = myself->connection->outmaclength;
 518         c->outcompression = myself->connection->outcompression;
 519
 520         c->address = sa;
 521         c->hostname = sockaddr2hostname(&sa);
 522         c->socket = fd;
 523         c->last_ping_time = time(NULL);
 524
 525         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection from %s", c->hostname);
 526
 527         event_set(&c->inevent, c->socket, EV_READ | EV_PERSIST, handle_meta_connection_data, c);
 528         event_add(&c->inevent, NULL);
 529         c->buffer = bufferevent_new(c->socket, NULL, handle_meta_write, handle_meta_connection_error, c);
 530         if(!c->buffer) {
 531                 logger(LOG_EMERG, "bufferevent_new() failed: %s", strerror(errno));
 532                 abort();
 533         }
 534         bufferevent_disable(c->buffer, EV_READ);
 535
 536         configure_tcp(c);
 537
 538         connection_add(c);
 539
 540         c->allow_request = ID;
 541         send_id(c);
 542 }
 543
 544 void free_outgoing(outgoing_t *outgoing) {
 545         if(outgoing->ai)
 546                 freeaddrinfo(outgoing->ai);
 547
 548         if(outgoing->name)
 549                 free(outgoing->name);
 550
 551         free(outgoing);
 552 }
 553
 554 void try_outgoing_connections(void) {
 555         static config_t *cfg = NULL;
 556         char *name;
 557         outgoing_t *outgoing;
 558         connection_t *c;
 559         splay_node_t *node;
 560
 561         if(outgoing_list) {
 562                 for(node = connection_tree->head; node; node = node->next) {
 563                         c = node->data;
 564                         c->outgoing = NULL;
 565                 }
 566
 567                 list_delete_list(outgoing_list);
 568         }
 569
 570         outgoing_list = list_alloc((list_action_t)free_outgoing);
 571
 572         for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 573                 get_config_string(cfg, &name);
 574
 575                 if(!check_id(name)) {
 576                         logger(LOG_ERR,
 577                                    "Invalid name for outgoing connection in %s line %d",
 578                                    cfg->file, cfg->line);
 579                         free(name);
 580                         continue;
 581                 }
 582
 583                 outgoing = xmalloc_and_zero(sizeof *outgoing);
 584                 outgoing->name = name;
 585                 list_insert_tail(outgoing_list, outgoing);
 586                 setup_outgoing_connection(outgoing);
 587         }
 588 }