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 "avl_tree.h"
  26 #include "conf.h"
  27 #include "connection.h"
  28 #include "event.h"
  29 #include "logger.h"
  30 #include "meta.h"
  31 #include "net.h"
  32 #include "netutl.h"
  33 #include "protocol.h"
  34 #include "utils.h"
  35 #include "xalloc.h"
  36
  37 #include <assert.h>
  38
  39 #ifdef WSAEINPROGRESS
  40 #define EINPROGRESS WSAEINPROGRESS
  41 #endif
  42
  43 /* Needed on Mac OS/X */
  44 #ifndef SOL_TCP
  45 #define SOL_TCP IPPROTO_TCP
  46 #endif
  47
  48 int addressfamily = AF_UNSPEC;
  49 int maxtimeout = 900;
  50 int seconds_till_retry = 5;
  51
  52 listen_socket_t listen_socket[MAXSOCKETS];
  53 int listen_sockets;
  54 list_t *outgoing_list = NULL;
  55
  56 /* Setup sockets */
  57
  58 static void configure_tcp(connection_t *c) {
  59         int option;
  60
  61 #ifdef O_NONBLOCK
  62         int flags = fcntl(c->socket, F_GETFL);
  63
  64         if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
  65                 logger(LOG_ERR, "fcntl for %s: %s", c->hostname, strerror(errno));
  66         }
  67 #elif defined(WIN32)
  68         unsigned long arg = 1;
  69
  70         if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
  71                 logger(LOG_ERR, "ioctlsocket for %s: WSA error %d", c->hostname, WSAGetLastError());
  72         }
  73 #endif
  74
  75 #if defined(SOL_TCP) && defined(TCP_NODELAY)
  76         option = 1;
  77         setsockopt(c->socket, SOL_TCP, TCP_NODELAY, &option, sizeof(option));
  78 #endif
  79
  80 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
  81         option = IPTOS_LOWDELAY;
  82         setsockopt(c->socket, SOL_IP, IP_TOS, &option, sizeof(option));
  83 #endif
  84 }
  85
  86 static bool bind_to_interface(int sd) {
  87         char *iface;
  88
  89 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  90         struct ifreq ifr;
  91         int status;
  92 #endif /* defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) */
  93
  94         if(!get_config_string (lookup_config (config_tree, "BindToInterface"), &iface))
  95                 return true;
  96
  97 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  98         memset(&ifr, 0, sizeof(ifr));
  99         strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
 100         ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
 101
 102         status = setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr));
 103         if(status) {
 104                 logger(LOG_ERR, "Can't bind to interface %s: %s", iface,
 105                                 strerror(errno));
 106                 return false;
 107         }
 108 #else /* if !defined(SOL_SOCKET) || !defined(SO_BINDTODEVICE) */
 109         logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 110 #endif
 111
 112         return true;
 113 }
 114
 115 static bool bind_to_address(connection_t *c) {
 116         char *node;
 117         struct addrinfo *ai_list;
 118         struct addrinfo *ai_ptr;
 119         struct addrinfo ai_hints;
 120         int status;
 121
 122         assert(c != NULL);
 123         assert(c->socket >= 0);
 124
 125         node = NULL;
 126         if(!get_config_string(lookup_config(config_tree, "BindToAddress"),
 127                                 &node))
 128                 return true;
 129
 130         assert(node != NULL);
 131
 132         memset(&ai_hints, 0, sizeof(ai_hints));
 133         ai_hints.ai_family = c->address.sa.sa_family;
 134         /* We're called from `do_outgoing_connection' only. */
 135         ai_hints.ai_socktype = SOCK_STREAM;
 136         ai_hints.ai_protocol = IPPROTO_TCP;
 137
 138         ai_list = NULL;
 139
 140         status = getaddrinfo(node, /* service = */ NULL,
 141                         &ai_hints, &ai_list);
 142         if(status) {
 143                 free(node);
 144                 logger(LOG_WARNING, "Error looking up %s port %s: %s",
 145                                 node, "any", gai_strerror(status));
 146                 return false;
 147         }
 148         assert(ai_list != NULL);
 149
 150         status = -1;
 151         for(ai_ptr = ai_list; ai_ptr != NULL; ai_ptr = ai_ptr->ai_next) {
 152                 status = bind(c->socket,
 153                                 ai_list->ai_addr, ai_list->ai_addrlen);
 154                 if(!status)
 155                         break;
 156         }
 157
 158
 159         if(status) {
 160                 logger(LOG_ERR, "Can't bind to %s/tcp: %s", node,
 161                                 strerror(errno));
 162         } else ifdebug(CONNECTIONS) {
 163                 logger(LOG_DEBUG, "Successfully bound outgoing "
 164                                 "TCP socket to %s", node);
 165         }
 166
 167         free(node);
 168         freeaddrinfo(ai_list);
 169
 170         return status ? false : true;
 171 }
 172
 173 int setup_listen_socket(const sockaddr_t *sa) {
 174         int nfd;
 175         char *addrstr;
 176         int option;
 177         char *iface;
 178
 179         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 180
 181         if(nfd < 0) {
 182                 ifdebug(STATUS) logger(LOG_ERR, "Creating metasocket failed: %s", strerror(errno));
 183                 return -1;
 184         }
 185
 186         /* Optimize TCP settings */
 187
 188         option = 1;
 189         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option));
 190
 191 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 192         if(sa->sa.sa_family == AF_INET6)
 193                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, &option, sizeof option);
 194 #endif
 195
 196         if(get_config_string
 197            (lookup_config(config_tree, "BindToInterface"), &iface)) {
 198 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
 199                 struct ifreq ifr;
 200
 201                 memset(&ifr, 0, sizeof(ifr));
 202                 strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
 203
 204                 if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr))) {
 205                         closesocket(nfd);
 206                         logger(LOG_ERR, "Can't bind to interface %s: %s", iface,
 207                                    strerror(errno));
 208                         return -1;
 209                 }
 210 #else
 211                 logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 212 #endif
 213         }
 214
 215         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 216                 closesocket(nfd);
 217                 addrstr = sockaddr2hostname(sa);
 218                 logger(LOG_ERR, "Can't bind to %s/tcp: %s", addrstr,
 219                            strerror(errno));
 220                 free(addrstr);
 221                 return -1;
 222         }
 223
 224         if(listen(nfd, 3)) {
 225                 closesocket(nfd);
 226                 logger(LOG_ERR, "System call `%s' failed: %s", "listen",
 227                            strerror(errno));
 228                 return -1;
 229         }
 230
 231         return nfd;
 232 }
 233
 234 int setup_vpn_in_socket(const sockaddr_t *sa) {
 235         int nfd;
 236         char *addrstr;
 237         int option;
 238
 239         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 240
 241         if(nfd < 0) {
 242                 logger(LOG_ERR, "Creating UDP socket failed: %s", strerror(errno));
 243                 return -1;
 244         }
 245
 246 #ifdef O_NONBLOCK
 247         {
 248                 int flags = fcntl(nfd, F_GETFL);
 249
 250                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
 251                         closesocket(nfd);
 252                         logger(LOG_ERR, "System call `%s' failed: %s", "fcntl",
 253                                    strerror(errno));
 254                         return -1;
 255                 }
 256         }
 257 #elif defined(WIN32)
 258         {
 259                 unsigned long arg = 1;
 260                 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
 261                         closesocket(nfd);
 262                         logger(LOG_ERR, "Call to `%s' failed: WSA error %d", "ioctlsocket",
 263                                 WSAGetLastError());
 264                         return -1;
 265                 }
 266         }
 267 #endif
 268
 269         option = 1;
 270         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option));
 271
 272 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 273         if(sa->sa.sa_family == AF_INET6)
 274                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, &option, sizeof option);
 275 #endif
 276
 277 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 278         if(myself->options & OPTION_PMTU_DISCOVERY) {
 279                 option = IP_PMTUDISC_DO;
 280                 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, &option, sizeof(option));
 281         }
 282 #endif
 283
 284 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 285         if(myself->options & OPTION_PMTU_DISCOVERY) {
 286                 option = IPV6_PMTUDISC_DO;
 287                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, &option, sizeof(option));
 288         }
 289 #endif
 290
 291         if (!bind_to_interface(nfd)) {
 292                 closesocket(nfd);
 293                 return -1;
 294         }
 295
 296         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 297                 closesocket(nfd);
 298                 addrstr = sockaddr2hostname(sa);
 299                 logger(LOG_ERR, "Can't bind to %s/udp: %s", addrstr,
 300                            strerror(errno));
 301                 free(addrstr);
 302                 return -1;
 303         }
 304
 305         return nfd;
 306 } /* int setup_vpn_in_socket */
 307
 308 void retry_outgoing(outgoing_t *outgoing) {
 309         event_t *event;
 310
 311         outgoing->timeout += 5;
 312
 313         if(outgoing->timeout > maxtimeout)
 314                 outgoing->timeout = maxtimeout;
 315
 316         event = new_event();
 317         event->handler = (event_handler_t) setup_outgoing_connection;
 318         event->time = now + outgoing->timeout;
 319         event->data = outgoing;
 320         event_add(event);
 321
 322         ifdebug(CONNECTIONS) logger(LOG_NOTICE,
 323                            "Trying to re-establish outgoing connection in %d seconds",
 324                            outgoing->timeout);
 325 }
 326
 327 void finish_connecting(connection_t *c) {
 328         ifdebug(CONNECTIONS) logger(LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 329
 330         configure_tcp(c);
 331
 332         c->last_ping_time = now;
 333
 334         send_id(c);
 335 }
 336
 337 void do_outgoing_connection(connection_t *c) {
 338         char *address, *port;
 339         int result;
 340
 341 begin:
 342         if(!c->outgoing->ai) {
 343                 if(!c->outgoing->cfg) {
 344                         ifdebug(CONNECTIONS) logger(LOG_ERR, "Could not set up a meta connection to %s",
 345                                            c->name);
 346                         c->status.remove = true;
 347                         retry_outgoing(c->outgoing);
 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 setup_outgoing_connection(outgoing_t *outgoing) {
 431         connection_t *c;
 432         node_t *n;
 433
 434         n = lookup_node(outgoing->name);
 435
 436         if(n)
 437                 if(n->connection) {
 438                         ifdebug(CONNECTIONS) logger(LOG_INFO, "Already connected to %s", outgoing->name);
 439
 440                         n->connection->outgoing = outgoing;
 441                         return;
 442                 }
 443
 444         c = new_connection();
 445         c->name = xstrdup(outgoing->name);
 446         c->outcipher = myself->connection->outcipher;
 447         c->outdigest = myself->connection->outdigest;
 448         c->outmaclength = myself->connection->outmaclength;
 449         c->outcompression = myself->connection->outcompression;
 450
 451         init_configuration(&c->config_tree);
 452         read_connection_config(c);
 453
 454         outgoing->cfg = lookup_config(c->config_tree, "Address");
 455
 456         if(!outgoing->cfg) {
 457                 logger(LOG_ERR, "No address specified for %s", c->name);
 458                 free_connection(c);
 459                 return;
 460         }
 461
 462         c->outgoing = outgoing;
 463         c->last_ping_time = now;
 464
 465         connection_add(c);
 466
 467         do_outgoing_connection(c);
 468 }
 469
 470 /*
 471   accept a new tcp connect and create a
 472   new connection
 473 */
 474 bool handle_new_meta_connection(int sock) {
 475         connection_t *c;
 476         sockaddr_t sa;
 477         int fd;
 478         socklen_t len = sizeof(sa);
 479
 480         fd = accept(sock, &sa.sa, &len);
 481
 482         if(fd < 0) {
 483                 logger(LOG_ERR, "Accepting a new connection failed: %s",
 484                            strerror(errno));
 485                 return false;
 486         }
 487
 488         sockaddrunmap(&sa);
 489
 490         c = new_connection();
 491         c->name = xstrdup("<unknown>");
 492         c->outcipher = myself->connection->outcipher;
 493         c->outdigest = myself->connection->outdigest;
 494         c->outmaclength = myself->connection->outmaclength;
 495         c->outcompression = myself->connection->outcompression;
 496
 497         c->address = sa;
 498         c->hostname = sockaddr2hostname(&sa);
 499         c->socket = fd;
 500         c->last_ping_time = now;
 501
 502         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection from %s", c->hostname);
 503
 504         configure_tcp(c);
 505
 506         connection_add(c);
 507
 508         c->allow_request = ID;
 509         send_id(c);
 510
 511         return true;
 512 }
 513
 514 void free_outgoing(outgoing_t *outgoing) {
 515         if(outgoing->ai)
 516                 freeaddrinfo(outgoing->ai);
 517
 518         if(outgoing->name)
 519                 free(outgoing->name);
 520
 521         free(outgoing);
 522 }
 523
 524 void try_outgoing_connections(void) {
 525         static config_t *cfg = NULL;
 526         char *name;
 527         outgoing_t *outgoing;
 528         connection_t *c;
 529         avl_node_t *node;
 530
 531         if(outgoing_list) {
 532                 for(node = connection_tree->head; node; node = node->next) {
 533                         c = node->data;
 534                         c->outgoing = NULL;
 535                 }
 536
 537                 list_delete_list(outgoing_list);
 538         }
 539
 540         outgoing_list = list_alloc((list_action_t)free_outgoing);
 541
 542         for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 543                 get_config_string(cfg, &name);
 544
 545                 if(!check_id(name)) {
 546                         logger(LOG_ERR,
 547                                    "Invalid name for outgoing connection in %s line %d",
 548                                    cfg->file, cfg->line);
 549                         free(name);
 550                         continue;
 551                 }
 552
 553                 outgoing = xmalloc_and_zero(sizeof(*outgoing));
 554                 outgoing->name = name;
 555                 list_insert_tail(outgoing_list, outgoing);
 556                 setup_outgoing_connection(outgoing);
 557         }
 558 }