git.meshlink.io Git - meshlink/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 "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 /* Needed on Mac OS/X */
  40 #ifndef SOL_TCP
  41 #define SOL_TCP IPPROTO_TCP
  42 #endif
  43
  44 int addressfamily = AF_UNSPEC;
  45 int maxtimeout = 900;
  46 int seconds_till_retry = 5;
  47
  48 listen_socket_t listen_socket[MAXSOCKETS];
  49 int listen_sockets;
  50 list_t *outgoing_list = NULL;
  51
  52 /* Setup sockets */
  53
  54 static void configure_tcp(connection_t *c) {
  55         int option;
  56
  57 #ifdef O_NONBLOCK
  58         int flags = fcntl(c->socket, F_GETFL);
  59
  60         if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
  61                 logger(LOG_ERR, "fcntl for %s: %s", c->hostname, strerror(errno));
  62         }
  63 #elif defined(WIN32)
  64         unsigned long arg = 1;
  65
  66         if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
  67                 logger(LOG_ERR, "ioctlsocket for %s: %d", c->hostname, sockstrerror(sockerrno));
  68         }
  69 #endif
  70
  71 #if defined(SOL_TCP) && defined(TCP_NODELAY)
  72         option = 1;
  73         setsockopt(c->socket, SOL_TCP, TCP_NODELAY, &option, sizeof(option));
  74 #endif
  75
  76 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
  77         option = IPTOS_LOWDELAY;
  78         setsockopt(c->socket, SOL_IP, IP_TOS, &option, sizeof(option));
  79 #endif
  80 }
  81
  82 static bool bind_to_interface(int sd) {
  83         char *iface;
  84
  85 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  86         struct ifreq ifr;
  87         int status;
  88 #endif /* defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) */
  89
  90         if(!get_config_string (lookup_config (config_tree, "BindToInterface"), &iface))
  91                 return true;
  92
  93 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  94         memset(&ifr, 0, sizeof(ifr));
  95         strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
  96         ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
  97
  98         status = setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr));
  99         if(status) {
 100                 logger(LOG_ERR, "Can't bind to interface %s: %s", iface,
 101                                 strerror(errno));
 102                 return false;
 103         }
 104 #else /* if !defined(SOL_SOCKET) || !defined(SO_BINDTODEVICE) */
 105         logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 106 #endif
 107
 108         return true;
 109 }
 110
 111 static bool bind_to_address(connection_t *c) {
 112         char *node;
 113         struct addrinfo *ai_list;
 114         struct addrinfo *ai_ptr;
 115         struct addrinfo ai_hints;
 116         int status;
 117
 118         assert(c != NULL);
 119         assert(c->socket >= 0);
 120
 121         node = NULL;
 122         if(!get_config_string(lookup_config(config_tree, "BindToAddress"),
 123                                 &node))
 124                 return true;
 125
 126         assert(node != NULL);
 127
 128         memset(&ai_hints, 0, sizeof(ai_hints));
 129         ai_hints.ai_family = c->address.sa.sa_family;
 130         /* We're called from `do_outgoing_connection' only. */
 131         ai_hints.ai_socktype = SOCK_STREAM;
 132         ai_hints.ai_protocol = IPPROTO_TCP;
 133
 134         ai_list = NULL;
 135
 136         status = getaddrinfo(node, /* service = */ NULL,
 137                         &ai_hints, &ai_list);
 138         if(status) {
 139                 free(node);
 140                 logger(LOG_WARNING, "Error looking up %s port %s: %s",
 141                                 node, "any", gai_strerror(status));
 142                 return false;
 143         }
 144         assert(ai_list != NULL);
 145
 146         status = -1;
 147         for(ai_ptr = ai_list; ai_ptr != NULL; ai_ptr = ai_ptr->ai_next) {
 148                 status = bind(c->socket,
 149                                 ai_list->ai_addr, ai_list->ai_addrlen);
 150                 if(!status)
 151                         break;
 152         }
 153
 154
 155         if(status) {
 156                 logger(LOG_ERR, "Can't bind to %s/tcp: %s", node, sockstrerror(sockerrno));
 157         } else ifdebug(CONNECTIONS) {
 158                 logger(LOG_DEBUG, "Successfully bound outgoing "
 159                                 "TCP socket to %s", node);
 160         }
 161
 162         free(node);
 163         freeaddrinfo(ai_list);
 164
 165         return status ? false : true;
 166 }
 167
 168 int setup_listen_socket(const sockaddr_t *sa) {
 169         int nfd;
 170         char *addrstr;
 171         int option;
 172         char *iface;
 173
 174         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 175
 176         if(nfd < 0) {
 177                 ifdebug(STATUS) logger(LOG_ERR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
 178                 return -1;
 179         }
 180
 181         /* Optimize TCP settings */
 182
 183         option = 1;
 184         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option));
 185
 186 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 187         if(sa->sa.sa_family == AF_INET6)
 188                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, &option, sizeof option);
 189 #endif
 190
 191         if(get_config_string
 192            (lookup_config(config_tree, "BindToInterface"), &iface)) {
 193 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
 194                 struct ifreq ifr;
 195
 196                 memset(&ifr, 0, sizeof(ifr));
 197                 strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
 198
 199                 if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr))) {
 200                         closesocket(nfd);
 201                         logger(LOG_ERR, "Can't bind to interface %s: %s", iface,
 202                                    strerror(sockerrno));
 203                         return -1;
 204                 }
 205 #else
 206                 logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 207 #endif
 208         }
 209
 210         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 211                 closesocket(nfd);
 212                 addrstr = sockaddr2hostname(sa);
 213                 logger(LOG_ERR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
 214                 free(addrstr);
 215                 return -1;
 216         }
 217
 218         if(listen(nfd, 3)) {
 219                 closesocket(nfd);
 220                 logger(LOG_ERR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
 221                 return -1;
 222         }
 223
 224         return nfd;
 225 }
 226
 227 int setup_vpn_in_socket(const sockaddr_t *sa) {
 228         int nfd;
 229         char *addrstr;
 230         int option;
 231
 232         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 233
 234         if(nfd < 0) {
 235                 logger(LOG_ERR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
 236                 return -1;
 237         }
 238
 239 #ifdef O_NONBLOCK
 240         {
 241                 int flags = fcntl(nfd, F_GETFL);
 242
 243                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
 244                         closesocket(nfd);
 245                         logger(LOG_ERR, "System call `%s' failed: %s", "fcntl",
 246                                    strerror(errno));
 247                         return -1;
 248                 }
 249         }
 250 #elif defined(WIN32)
 251         {
 252                 unsigned long arg = 1;
 253                 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
 254                         closesocket(nfd);
 255                         logger(LOG_ERR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
 256                         return -1;
 257                 }
 258         }
 259 #endif
 260
 261         option = 1;
 262         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option));
 263
 264 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
 265         if(sa->sa.sa_family == AF_INET6)
 266                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, &option, sizeof option);
 267 #endif
 268
 269 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
 270 #define IP_DONTFRAGMENT IP_DONTFRAG
 271 #endif
 272
 273 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 274         if(myself->options & OPTION_PMTU_DISCOVERY) {
 275                 option = IP_PMTUDISC_DO;
 276                 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, &option, sizeof(option));
 277         }
 278 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
 279         if(myself->options & OPTION_PMTU_DISCOVERY) {
 280                 option = 1;
 281                 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, &option, sizeof(option));
 282         }
 283 #else
 284 #warning No way to disable IPv4 fragmentation
 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 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
 293         if(myself->options & OPTION_PMTU_DISCOVERY) {
 294                 option = 1;
 295                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, &option, sizeof(option));
 296         }
 297 #else
 298 #warning No way to disable IPv6 fragmentation
 299 #endif
 300
 301         if (!bind_to_interface(nfd)) {
 302                 closesocket(nfd);
 303                 return -1;
 304         }
 305
 306         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 307                 closesocket(nfd);
 308                 addrstr = sockaddr2hostname(sa);
 309                 logger(LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
 310                 free(addrstr);
 311                 return -1;
 312         }
 313
 314         return nfd;
 315 } /* int setup_vpn_in_socket */
 316
 317 void retry_outgoing(outgoing_t *outgoing) {
 318         outgoing->timeout += 5;
 319
 320         if(outgoing->timeout > maxtimeout)
 321                 outgoing->timeout = maxtimeout;
 322
 323         if(outgoing->event)
 324                 event_del(outgoing->event);
 325         outgoing->event = new_event();
 326         outgoing->event->handler = (event_handler_t) setup_outgoing_connection;
 327         outgoing->event->time = now + outgoing->timeout;
 328         outgoing->event->data = outgoing;
 329         event_add(outgoing->event);
 330
 331         ifdebug(CONNECTIONS) logger(LOG_NOTICE,
 332                            "Trying to re-establish outgoing connection in %d seconds",
 333                            outgoing->timeout);
 334 }
 335
 336 void finish_connecting(connection_t *c) {
 337         ifdebug(CONNECTIONS) logger(LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 338
 339         configure_tcp(c);
 340
 341         c->last_ping_time = now;
 342
 343         send_id(c);
 344 }
 345
 346 void do_outgoing_connection(connection_t *c) {
 347         char *address, *port, *space;
 348         int result;
 349
 350         if(!c->outgoing) {
 351                 logger(LOG_ERR, "do_outgoing_connection() for %s called without c->outgoing", c->name);
 352                 abort();
 353         }
 354
 355 begin:
 356         if(!c->outgoing->ai) {
 357                 if(!c->outgoing->cfg) {
 358                         ifdebug(CONNECTIONS) logger(LOG_ERR, "Could not set up a meta connection to %s",
 359                                            c->name);
 360                         c->status.remove = true;
 361                         retry_outgoing(c->outgoing);
 362                         c->outgoing = NULL;
 363                         return;
 364                 }
 365
 366                 get_config_string(c->outgoing->cfg, &address);
 367
 368                 space = strchr(address, ' ');
 369                 if(space) {
 370                         port = xstrdup(space + 1);
 371                         *space = 0;
 372                 } else {
 373                         if(!get_config_string(lookup_config(c->config_tree, "Port"), &port))
 374                                 port = xstrdup("655");
 375                 }
 376
 377                 c->outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 378                 free(address);
 379                 free(port);
 380
 381                 c->outgoing->aip = c->outgoing->ai;
 382                 c->outgoing->cfg = lookup_config_next(c->config_tree, c->outgoing->cfg);
 383         }
 384
 385         if(!c->outgoing->aip) {
 386                 if(c->outgoing->ai)
 387                         freeaddrinfo(c->outgoing->ai);
 388                 c->outgoing->ai = NULL;
 389                 goto begin;
 390         }
 391
 392         memcpy(&c->address, c->outgoing->aip->ai_addr, c->outgoing->aip->ai_addrlen);
 393         c->outgoing->aip = c->outgoing->aip->ai_next;
 394
 395         if(c->hostname)
 396                 free(c->hostname);
 397
 398         c->hostname = sockaddr2hostname(&c->address);
 399
 400         ifdebug(CONNECTIONS) logger(LOG_INFO, "Trying to connect to %s (%s)", c->name,
 401                            c->hostname);
 402
 403         c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 404
 405         if(c->socket == -1) {
 406                 ifdebug(CONNECTIONS) logger(LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
 407                 goto begin;
 408         }
 409
 410 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 411         int option = 1;
 412         if(c->address.sa.sa_family == AF_INET6)
 413                 setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, &option, sizeof option);
 414 #endif
 415
 416         bind_to_interface(c->socket);
 417         bind_to_address(c);
 418
 419         /* Optimize TCP settings */
 420
 421         configure_tcp(c);
 422
 423         /* Connect */
 424
 425         result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 426
 427         if(result == -1) {
 428                 if(sockinprogress(sockerrno)) {
 429                         c->status.connecting = true;
 430                         return;
 431                 }
 432
 433                 closesocket(c->socket);
 434
 435                 ifdebug(CONNECTIONS) logger(LOG_ERR, "%s: %s", c->hostname, sockstrerror(sockerrno));
 436
 437                 goto begin;
 438         }
 439
 440         finish_connecting(c);
 441
 442         return;
 443 }
 444
 445 void setup_outgoing_connection(outgoing_t *outgoing) {
 446         connection_t *c;
 447         node_t *n;
 448
 449         outgoing->event = NULL;
 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 = now;
 481
 482         connection_add(c);
 483
 484         do_outgoing_connection(c);
 485 }
 486
 487 /*
 488   accept a new tcp connect and create a
 489   new connection
 490 */
 491 bool handle_new_meta_connection(int sock) {
 492         connection_t *c;
 493         sockaddr_t sa;
 494         int fd;
 495         socklen_t len = sizeof(sa);
 496
 497         fd = accept(sock, &sa.sa, &len);
 498
 499         if(fd < 0) {
 500                 logger(LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 501                 return false;
 502         }
 503
 504         sockaddrunmap(&sa);
 505
 506         c = new_connection();
 507         c->name = xstrdup("<unknown>");
 508         c->outcipher = myself->connection->outcipher;
 509         c->outdigest = myself->connection->outdigest;
 510         c->outmaclength = myself->connection->outmaclength;
 511         c->outcompression = myself->connection->outcompression;
 512
 513         c->address = sa;
 514         c->hostname = sockaddr2hostname(&sa);
 515         c->socket = fd;
 516         c->last_ping_time = now;
 517
 518         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection from %s", c->hostname);
 519
 520         configure_tcp(c);
 521
 522         connection_add(c);
 523
 524         c->allow_request = ID;
 525         send_id(c);
 526
 527         return true;
 528 }
 529
 530 void free_outgoing(outgoing_t *outgoing) {
 531         if(outgoing->ai)
 532                 freeaddrinfo(outgoing->ai);
 533
 534         if(outgoing->name)
 535                 free(outgoing->name);
 536
 537         free(outgoing);
 538 }
 539
 540 void try_outgoing_connections(void) {
 541         static config_t *cfg = NULL;
 542         char *name;
 543         outgoing_t *outgoing;
 544
 545         outgoing_list = list_alloc((list_action_t)free_outgoing);
 546
 547         for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 548                 get_config_string(cfg, &name);
 549
 550                 if(!check_id(name)) {
 551                         logger(LOG_ERR,
 552                                    "Invalid name for outgoing connection in %s line %d",
 553                                    cfg->file, cfg->line);
 554                         free(name);
 555                         continue;
 556                 }
 557
 558                 outgoing = xmalloc_and_zero(sizeof(*outgoing));
 559                 outgoing->name = name;
 560                 list_insert_tail(outgoing_list, outgoing);
 561                 setup_outgoing_connection(outgoing);
 562         }
 563 }