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 #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                 free(node);
 141                 logger(LOG_WARNING, "Error looking up %s port %s: %s",
 142                                 node, "any", gai_strerror(status));
 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         option = 1;
 241         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
 242
 243         if(udp_rcvbuf && setsockopt(nfd, SOL_SOCKET, SO_RCVBUF, (void *)&udp_rcvbuf, sizeof(udp_rcvbuf)))
 244                 logger(LOG_WARNING, "Can't set UDP SO_RCVBUF to %i: %s", udp_rcvbuf, strerror(errno));
 245
 246         if(udp_sndbuf && setsockopt(nfd, SOL_SOCKET, SO_SNDBUF, (void *)&udp_sndbuf, sizeof(udp_sndbuf)))
 247                 logger(LOG_WARNING, "Can't set UDP SO_SNDBUF to %i: %s", udp_sndbuf, strerror(errno));
 248
 249 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
 250         if(sa->sa.sa_family == AF_INET6)
 251                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 252 #endif
 253
 254 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
 255 #define IP_DONTFRAGMENT IP_DONTFRAG
 256 #endif
 257
 258 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 259         if(myself->options & OPTION_PMTU_DISCOVERY) {
 260                 option = IP_PMTUDISC_DO;
 261                 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
 262         }
 263 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
 264         if(myself->options & OPTION_PMTU_DISCOVERY) {
 265                 option = 1;
 266                 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
 267         }
 268 #else
 269 #warning No way to disable IPv4 fragmentation
 270 #endif
 271
 272 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 273         if(myself->options & OPTION_PMTU_DISCOVERY) {
 274                 option = IPV6_PMTUDISC_DO;
 275                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
 276         }
 277 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
 278         if(myself->options & OPTION_PMTU_DISCOVERY) {
 279                 option = 1;
 280                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
 281         }
 282 #else
 283 #warning No way to disable IPv6 fragmentation
 284 #endif
 285
 286         if (!bind_to_interface(nfd)) {
 287                 closesocket(nfd);
 288                 return -1;
 289         }
 290
 291         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 292                 closesocket(nfd);
 293                 addrstr = sockaddr2hostname(sa);
 294                 logger(LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
 295                 free(addrstr);
 296                 return -1;
 297         }
 298
 299         return nfd;
 300 } /* int setup_vpn_in_socket */
 301
 302 static void retry_outgoing_handler(int fd, short events, void *data) {
 303         setup_outgoing_connection(data);
 304 }
 305
 306 void retry_outgoing(outgoing_t *outgoing) {
 307         outgoing->timeout += 5;
 308
 309         if(outgoing->timeout > maxtimeout)
 310                 outgoing->timeout = maxtimeout;
 311
 312         timeout_set(&outgoing->ev, retry_outgoing_handler, outgoing);
 313         event_add(&outgoing->ev, &(struct timeval){outgoing->timeout, 0});
 314
 315         ifdebug(CONNECTIONS) logger(LOG_NOTICE,
 316                            "Trying to re-establish outgoing connection in %d seconds",
 317                            outgoing->timeout);
 318 }
 319
 320 void finish_connecting(connection_t *c) {
 321         ifdebug(CONNECTIONS) logger(LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 322
 323         configure_tcp(c);
 324
 325         c->last_ping_time = time(NULL);
 326         c->status.connecting = false;
 327
 328         send_id(c);
 329 }
 330
 331 void do_outgoing_connection(connection_t *c) {
 332         char *address, *port, *space;
 333         int result;
 334
 335         if(!c->outgoing) {
 336                 logger(LOG_ERR, "do_outgoing_connection() for %s called without c->outgoing", c->name);
 337                 abort();
 338         }
 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                 space = strchr(address, ' ');
 354                 if(space) {
 355                         port = xstrdup(space + 1);
 356                         *space = 0;
 357                 } else {
 358                         if(!get_config_string(lookup_config(c->config_tree, "Port"), &port))
 359                                 port = xstrdup("655");
 360                 }
 361
 362                 c->outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 363                 free(address);
 364                 free(port);
 365
 366                 c->outgoing->aip = c->outgoing->ai;
 367                 c->outgoing->cfg = lookup_config_next(c->config_tree, c->outgoing->cfg);
 368         }
 369
 370         if(!c->outgoing->aip) {
 371                 if(c->outgoing->ai)
 372                         freeaddrinfo(c->outgoing->ai);
 373                 c->outgoing->ai = NULL;
 374                 goto begin;
 375         }
 376
 377         memcpy(&c->address, c->outgoing->aip->ai_addr, c->outgoing->aip->ai_addrlen);
 378         c->outgoing->aip = c->outgoing->aip->ai_next;
 379
 380         if(c->hostname)
 381                 free(c->hostname);
 382
 383         c->hostname = sockaddr2hostname(&c->address);
 384
 385         ifdebug(CONNECTIONS) logger(LOG_INFO, "Trying to connect to %s (%s)", c->name,
 386                            c->hostname);
 387
 388         c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 389
 390         if(c->socket == -1) {
 391                 ifdebug(CONNECTIONS) logger(LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
 392                 goto begin;
 393         }
 394
 395 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 396         int option = 1;
 397         if(c->address.sa.sa_family == AF_INET6)
 398                 setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 399 #endif
 400
 401         bind_to_interface(c->socket);
 402         bind_to_address(c);
 403
 404         /* Optimize TCP settings */
 405
 406         configure_tcp(c);
 407
 408         /* Connect */
 409
 410         result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 411
 412         if(result == -1) {
 413                 if(sockinprogress(sockerrno)) {
 414                         c->status.connecting = true;
 415                         return;
 416                 }
 417
 418                 closesocket(c->socket);
 419
 420                 ifdebug(CONNECTIONS) logger(LOG_ERR, "%s: %s", c->hostname, sockstrerror(sockerrno));
 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_ERR, "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_ERR, "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         event_del(&outgoing->ev);
 450
 451         n = lookup_node(outgoing->name);
 452
 453         if(n)
 454                 if(n->connection) {
 455                         ifdebug(CONNECTIONS) logger(LOG_INFO, "Already connected to %s", outgoing->name);
 456
 457                         n->connection->outgoing = outgoing;
 458                         return;
 459                 }
 460
 461         c = new_connection();
 462         c->name = xstrdup(outgoing->name);
 463         c->outcipher = myself->connection->outcipher;
 464         c->outdigest = myself->connection->outdigest;
 465         c->outmaclength = myself->connection->outmaclength;
 466         c->outcompression = myself->connection->outcompression;
 467
 468         init_configuration(&c->config_tree);
 469         read_connection_config(c);
 470
 471         outgoing->cfg = lookup_config(c->config_tree, "Address");
 472
 473         if(!outgoing->cfg) {
 474                 logger(LOG_ERR, "No address specified for %s", c->name);
 475                 free_connection(c);
 476                 return;
 477         }
 478
 479         c->outgoing = outgoing;
 480         c->last_ping_time = time(NULL);
 481
 482         connection_add(c);
 483
 484         do_outgoing_connection(c);
 485
 486         event_set(&c->inevent, c->socket, EV_READ | EV_PERSIST, handle_meta_connection_data, c);
 487         event_add(&c->inevent, NULL);
 488         c->buffer = bufferevent_new(c->socket, handle_meta_read, handle_meta_write, handle_meta_connection_error, c);
 489         if(!c->buffer) {
 490                 logger(LOG_ERR, "bufferevent_new() failed: %s", strerror(errno));
 491                 abort();
 492         }
 493         bufferevent_disable(c->buffer, EV_READ);
 494 }
 495
 496 /*
 497   accept a new tcp connect and create a
 498   new connection
 499 */
 500 void handle_new_meta_connection(int sock, short events, void *data) {
 501         connection_t *c;
 502         sockaddr_t sa;
 503         int fd;
 504         socklen_t len = sizeof sa;
 505
 506         fd = accept(sock, &sa.sa, &len);
 507
 508         if(fd < 0) {
 509                 logger(LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 510                 return;
 511         }
 512
 513         sockaddrunmap(&sa);
 514
 515         c = new_connection();
 516         c->name = xstrdup("<unknown>");
 517         c->outcipher = myself->connection->outcipher;
 518         c->outdigest = myself->connection->outdigest;
 519         c->outmaclength = myself->connection->outmaclength;
 520         c->outcompression = myself->connection->outcompression;
 521
 522         c->address = sa;
 523         c->hostname = sockaddr2hostname(&sa);
 524         c->socket = fd;
 525         c->last_ping_time = time(NULL);
 526
 527         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection from %s", c->hostname);
 528
 529         event_set(&c->inevent, c->socket, EV_READ | EV_PERSIST, handle_meta_connection_data, c);
 530         event_add(&c->inevent, NULL);
 531         c->buffer = bufferevent_new(c->socket, NULL, handle_meta_write, handle_meta_connection_error, c);
 532         if(!c->buffer) {
 533                 logger(LOG_ERR, "bufferevent_new() failed: %s", strerror(errno));
 534                 abort();
 535         }
 536         bufferevent_disable(c->buffer, EV_READ);
 537
 538         configure_tcp(c);
 539
 540         connection_add(c);
 541
 542         c->allow_request = ID;
 543         send_id(c);
 544 }
 545
 546 void free_outgoing(outgoing_t *outgoing) {
 547         if(outgoing->ai)
 548                 freeaddrinfo(outgoing->ai);
 549
 550         if(outgoing->name)
 551                 free(outgoing->name);
 552
 553         free(outgoing);
 554 }
 555
 556 void try_outgoing_connections(void) {
 557         static config_t *cfg = NULL;
 558         char *name;
 559         outgoing_t *outgoing;
 560
 561         outgoing_list = list_alloc((list_action_t)free_outgoing);
 562
 563         for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 564                 get_config_string(cfg, &name);
 565
 566                 if(!check_id(name)) {
 567                         logger(LOG_ERR,
 568                                    "Invalid name for outgoing connection in %s line %d",
 569                                    cfg->file, cfg->line);
 570                         free(name);
 571                         continue;
 572                 }
 573
 574                 outgoing = xmalloc_and_zero(sizeof *outgoing);
 575                 outgoing->name = name;
 576                 list_insert_tail(outgoing_list, outgoing);
 577                 setup_outgoing_connection(outgoing);
 578         }
 579 }