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                   2000-2012 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 /* Needed on Mac OS/X */
  37 #ifndef SOL_TCP
  38 #define SOL_TCP IPPROTO_TCP
  39 #endif
  40
  41 int addressfamily = AF_UNSPEC;
  42 int maxtimeout = 900;
  43 int seconds_till_retry = 5;
  44 int udp_rcvbuf = 0;
  45 int udp_sndbuf = 0;
  46
  47 listen_socket_t listen_socket[MAXSOCKETS];
  48 int listen_sockets;
  49 list_t *outgoing_list = NULL;
  50
  51 /* Setup sockets */
  52
  53 static void configure_tcp(connection_t *c) {
  54         int option;
  55
  56 #ifdef O_NONBLOCK
  57         int flags = fcntl(c->socket, F_GETFL);
  58
  59         if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
  60                 logger(DEBUG_ALWAYS, LOG_ERR, "fcntl for %s: %s", c->hostname, strerror(errno));
  61         }
  62 #elif defined(WIN32)
  63         unsigned long arg = 1;
  64
  65         if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
  66                 logger(DEBUG_ALWAYS, LOG_ERR, "ioctlsocket for %s: %d", c->hostname, sockstrerror(sockerrno));
  67         }
  68 #endif
  69
  70 #if defined(SOL_TCP) && defined(TCP_NODELAY)
  71         option = 1;
  72         setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&option, sizeof option);
  73 #endif
  74
  75 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
  76         option = IPTOS_LOWDELAY;
  77         setsockopt(c->socket, SOL_IP, IP_TOS, (void *)&option, sizeof option);
  78 #endif
  79 }
  80
  81 static bool bind_to_interface(int sd) {
  82         char *iface;
  83
  84 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  85         struct ifreq ifr;
  86         int status;
  87 #endif /* defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) */
  88
  89         if(!get_config_string (lookup_config (config_tree, "BindToInterface"), &iface))
  90                 return true;
  91
  92 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  93         memset(&ifr, 0, sizeof(ifr));
  94         strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
  95         ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
  96
  97         status = setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr));
  98         if(status) {
  99                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to interface %s: %s", iface,
 100                                 strerror(errno));
 101                 return false;
 102         }
 103 #else /* if !defined(SOL_SOCKET) || !defined(SO_BINDTODEVICE) */
 104         logger(DEBUG_ALWAYS, LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 105 #endif
 106
 107         return true;
 108 }
 109
 110 int setup_listen_socket(const sockaddr_t *sa) {
 111         int nfd;
 112         char *addrstr;
 113         int option;
 114         char *iface;
 115
 116         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 117
 118         if(nfd < 0) {
 119                 logger(DEBUG_STATUS, LOG_ERR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
 120                 return -1;
 121         }
 122
 123 #ifdef FD_CLOEXEC
 124         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 125 #endif
 126
 127         /* Optimize TCP settings */
 128
 129         option = 1;
 130         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
 131
 132 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 133         if(sa->sa.sa_family == AF_INET6)
 134                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 135 #endif
 136
 137         if(get_config_string
 138            (lookup_config(config_tree, "BindToInterface"), &iface)) {
 139 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
 140                 struct ifreq ifr;
 141
 142                 memset(&ifr, 0, sizeof ifr);
 143                 strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
 144
 145                 if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof ifr)) {
 146                         closesocket(nfd);
 147                         logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to interface %s: %s", iface,
 148                                    strerror(sockerrno));
 149                         return -1;
 150                 }
 151 #else
 152                 logger(DEBUG_ALWAYS, LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 153 #endif
 154         }
 155
 156         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 157                 closesocket(nfd);
 158                 addrstr = sockaddr2hostname(sa);
 159                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
 160                 free(addrstr);
 161                 return -1;
 162         }
 163
 164         if(listen(nfd, 3)) {
 165                 closesocket(nfd);
 166                 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
 167                 return -1;
 168         }
 169
 170         return nfd;
 171 }
 172
 173 int setup_vpn_in_socket(const sockaddr_t *sa) {
 174         int nfd;
 175         char *addrstr;
 176         int option;
 177
 178         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 179
 180         if(nfd < 0) {
 181                 logger(DEBUG_ALWAYS, LOG_ERR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
 182                 return -1;
 183         }
 184
 185 #ifdef FD_CLOEXEC
 186         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 187 #endif
 188
 189 #ifdef O_NONBLOCK
 190         {
 191                 int flags = fcntl(nfd, F_GETFL);
 192
 193                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
 194                         closesocket(nfd);
 195                         logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "fcntl",
 196                                    strerror(errno));
 197                         return -1;
 198                 }
 199         }
 200 #elif defined(WIN32)
 201         {
 202                 unsigned long arg = 1;
 203                 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
 204                         closesocket(nfd);
 205                         logger(DEBUG_ALWAYS, LOG_ERR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
 206                         return -1;
 207                 }
 208         }
 209 #endif
 210
 211         option = 1;
 212         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
 213         setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof option);
 214
 215         if(udp_rcvbuf && setsockopt(nfd, SOL_SOCKET, SO_RCVBUF, (void *)&udp_rcvbuf, sizeof(udp_rcvbuf)))
 216                 logger(DEBUG_ALWAYS, LOG_WARNING, "Can't set UDP SO_RCVBUF to %i: %s", udp_rcvbuf, strerror(errno));
 217
 218         if(udp_sndbuf && setsockopt(nfd, SOL_SOCKET, SO_SNDBUF, (void *)&udp_sndbuf, sizeof(udp_sndbuf)))
 219                 logger(DEBUG_ALWAYS, LOG_WARNING, "Can't set UDP SO_SNDBUF to %i: %s", udp_sndbuf, strerror(errno));
 220
 221 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
 222         if(sa->sa.sa_family == AF_INET6)
 223                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 224 #endif
 225
 226 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
 227 #define IP_DONTFRAGMENT IP_DONTFRAG
 228 #endif
 229
 230 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 231         if(myself->options & OPTION_PMTU_DISCOVERY) {
 232                 option = IP_PMTUDISC_DO;
 233                 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
 234         }
 235 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
 236         if(myself->options & OPTION_PMTU_DISCOVERY) {
 237                 option = 1;
 238                 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
 239         }
 240 #else
 241 #warning No way to disable IPv4 fragmentation
 242 #endif
 243
 244 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 245         if(myself->options & OPTION_PMTU_DISCOVERY) {
 246                 option = IPV6_PMTUDISC_DO;
 247                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
 248         }
 249 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
 250         if(myself->options & OPTION_PMTU_DISCOVERY) {
 251                 option = 1;
 252                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
 253         }
 254 #else
 255 #warning No way to disable IPv6 fragmentation
 256 #endif
 257
 258         if (!bind_to_interface(nfd)) {
 259                 closesocket(nfd);
 260                 return -1;
 261         }
 262
 263         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 264                 closesocket(nfd);
 265                 addrstr = sockaddr2hostname(sa);
 266                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
 267                 free(addrstr);
 268                 return -1;
 269         }
 270
 271         return nfd;
 272 } /* int setup_vpn_in_socket */
 273
 274 static void retry_outgoing_handler(int fd, short events, void *data) {
 275         setup_outgoing_connection(data);
 276 }
 277
 278 void retry_outgoing(outgoing_t *outgoing) {
 279         outgoing->timeout += 5;
 280
 281         if(outgoing->timeout > maxtimeout)
 282                 outgoing->timeout = maxtimeout;
 283
 284         timeout_set(&outgoing->ev, retry_outgoing_handler, outgoing);
 285         event_add(&outgoing->ev, &(struct timeval){outgoing->timeout, 0});
 286
 287         logger(DEBUG_CONNECTIONS, LOG_NOTICE,
 288                            "Trying to re-establish outgoing connection in %d seconds",
 289                            outgoing->timeout);
 290 }
 291
 292 void finish_connecting(connection_t *c) {
 293         logger(DEBUG_CONNECTIONS, LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 294
 295         configure_tcp(c);
 296
 297         c->last_ping_time = time(NULL);
 298         c->status.connecting = false;
 299
 300         send_id(c);
 301 }
 302
 303 bool do_outgoing_connection(connection_t *c) {
 304         char *address, *port, *space;
 305         int result;
 306
 307         if(!c->outgoing) {
 308                 logger(DEBUG_ALWAYS, LOG_ERR, "do_outgoing_connection() for %s called without c->outgoing", c->name);
 309                 abort();
 310         }
 311
 312 begin:
 313         if(!c->outgoing->ai) {
 314                 if(!c->outgoing->cfg) {
 315                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not set up a meta connection to %s",
 316                                            c->name);
 317                         retry_outgoing(c->outgoing);
 318                         c->outgoing = NULL;
 319                         connection_del(c);
 320                         return false;
 321                 }
 322
 323                 get_config_string(c->outgoing->cfg, &address);
 324
 325                 space = strchr(address, ' ');
 326                 if(space) {
 327                         port = xstrdup(space + 1);
 328                         *space = 0;
 329                 } else {
 330                         if(!get_config_string(lookup_config(c->config_tree, "Port"), &port))
 331                                 port = xstrdup("655");
 332                 }
 333
 334                 c->outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 335                 free(address);
 336                 free(port);
 337
 338                 c->outgoing->aip = c->outgoing->ai;
 339                 c->outgoing->cfg = lookup_config_next(c->config_tree, c->outgoing->cfg);
 340         }
 341
 342         if(!c->outgoing->aip) {
 343                 if(c->outgoing->ai)
 344                         freeaddrinfo(c->outgoing->ai);
 345                 c->outgoing->ai = NULL;
 346                 goto begin;
 347         }
 348
 349         memcpy(&c->address, c->outgoing->aip->ai_addr, c->outgoing->aip->ai_addrlen);
 350         c->outgoing->aip = c->outgoing->aip->ai_next;
 351
 352         if(c->hostname)
 353                 free(c->hostname);
 354
 355         c->hostname = sockaddr2hostname(&c->address);
 356
 357         logger(DEBUG_CONNECTIONS, LOG_INFO, "Trying to connect to %s (%s)", c->name,
 358                            c->hostname);
 359
 360         c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 361
 362 #ifdef FD_CLOEXEC
 363         fcntl(c->socket, F_SETFD, FD_CLOEXEC);
 364 #endif
 365
 366         if(c->socket == -1) {
 367                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
 368                 goto begin;
 369         }
 370
 371 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 372         int option = 1;
 373         if(c->address.sa.sa_family == AF_INET6)
 374                 setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 375 #endif
 376
 377         bind_to_interface(c->socket);
 378
 379         /* Optimize TCP settings */
 380
 381         configure_tcp(c);
 382
 383         /* Connect */
 384
 385         result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 386
 387         if(result == -1) {
 388                 if(sockinprogress(sockerrno)) {
 389                         c->status.connecting = true;
 390                         return true;
 391                 }
 392
 393                 closesocket(c->socket);
 394
 395                 logger(DEBUG_CONNECTIONS, LOG_ERR, "%s: %s", c->hostname, sockstrerror(sockerrno));
 396
 397                 goto begin;
 398         }
 399
 400         finish_connecting(c);
 401
 402         return true;
 403 }
 404
 405 static void handle_meta_write(int sock, short events, void *data) {
 406         connection_t *c = data;
 407
 408         ssize_t outlen = send(c->socket, c->outbuf.data + c->outbuf.offset, c->outbuf.len - c->outbuf.offset, 0);
 409         if(outlen <= 0) {
 410                 logger(DEBUG_ALWAYS, LOG_ERR, "Onoes, outlen = %d (%s)", (int)outlen, strerror(errno));
 411                 terminate_connection(c, c->status.active);
 412                 return;
 413         }
 414
 415         buffer_read(&c->outbuf, outlen);
 416         if(!c->outbuf.len && event_initialized(&c->outevent))
 417                 event_del(&c->outevent);
 418 }
 419
 420 void setup_outgoing_connection(outgoing_t *outgoing) {
 421         connection_t *c;
 422         node_t *n;
 423
 424         if(event_initialized(&outgoing->ev))
 425                 event_del(&outgoing->ev);
 426
 427         n = lookup_node(outgoing->name);
 428
 429         if(n)
 430                 if(n->connection) {
 431                         logger(DEBUG_CONNECTIONS, LOG_INFO, "Already connected to %s", outgoing->name);
 432
 433                         n->connection->outgoing = outgoing;
 434                         return;
 435                 }
 436
 437         c = new_connection();
 438         c->name = xstrdup(outgoing->name);
 439         c->outcipher = myself->connection->outcipher;
 440         c->outdigest = myself->connection->outdigest;
 441         c->outmaclength = myself->connection->outmaclength;
 442         c->outcompression = myself->connection->outcompression;
 443
 444         init_configuration(&c->config_tree);
 445         read_connection_config(c);
 446
 447         outgoing->cfg = lookup_config(c->config_tree, "Address");
 448
 449         if(!outgoing->cfg) {
 450                 logger(DEBUG_ALWAYS, LOG_ERR, "No address specified for %s", c->name);
 451                 free_connection(c);
 452                 return;
 453         }
 454
 455         c->outgoing = outgoing;
 456         c->last_ping_time = time(NULL);
 457
 458         connection_add(c);
 459
 460         if (do_outgoing_connection(c)) {
 461                 event_set(&c->inevent, c->socket, EV_READ | EV_PERSIST, handle_meta_connection_data, c);
 462                 event_set(&c->outevent, c->socket, EV_WRITE | EV_PERSIST, handle_meta_write, c);
 463                 event_add(&c->inevent, NULL);
 464         }
 465 }
 466
 467 /*
 468   accept a new tcp connect and create a
 469   new connection
 470 */
 471 void handle_new_meta_connection(int sock, short events, void *data) {
 472         connection_t *c;
 473         sockaddr_t sa;
 474         int fd;
 475         socklen_t len = sizeof sa;
 476
 477         fd = accept(sock, &sa.sa, &len);
 478
 479         if(fd < 0) {
 480                 logger(DEBUG_ALWAYS, LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 481                 return;
 482         }
 483
 484         sockaddrunmap(&sa);
 485
 486         c = new_connection();
 487         c->name = xstrdup("<unknown>");
 488         c->outcipher = myself->connection->outcipher;
 489         c->outdigest = myself->connection->outdigest;
 490         c->outmaclength = myself->connection->outmaclength;
 491         c->outcompression = myself->connection->outcompression;
 492
 493         c->address = sa;
 494         c->hostname = sockaddr2hostname(&sa);
 495         c->socket = fd;
 496         c->last_ping_time = time(NULL);
 497
 498         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection from %s", c->hostname);
 499
 500         event_set(&c->inevent, c->socket, EV_READ | EV_PERSIST, handle_meta_connection_data, c);
 501         event_set(&c->outevent, c->socket, EV_WRITE | EV_PERSIST, handle_meta_write, c);
 502         event_add(&c->inevent, NULL);
 503
 504         configure_tcp(c);
 505
 506         connection_add(c);
 507
 508         c->allow_request = ID;
 509         send_id(c);
 510 }
 511
 512 static void free_outgoing(outgoing_t *outgoing) {
 513         if(outgoing->ai)
 514                 freeaddrinfo(outgoing->ai);
 515
 516         if(outgoing->name)
 517                 free(outgoing->name);
 518
 519         free(outgoing);
 520 }
 521
 522 void try_outgoing_connections(void) {
 523         static config_t *cfg = NULL;
 524         char *name;
 525         outgoing_t *outgoing;
 526
 527         outgoing_list = list_alloc((list_action_t)free_outgoing);
 528
 529         for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 530                 get_config_string(cfg, &name);
 531
 532                 if(!check_id(name)) {
 533                         logger(DEBUG_ALWAYS, LOG_ERR,
 534                                    "Invalid name for outgoing connection in %s line %d",
 535                                    cfg->file, cfg->line);
 536                         free(name);
 537                         continue;
 538                 }
 539
 540                 outgoing = xmalloc_and_zero(sizeof *outgoing);
 541                 outgoing->name = name;
 542                 list_insert_tail(outgoing_list, outgoing);
 543                 setup_outgoing_connection(outgoing);
 544         }
 545 }