src/net_socket.c

   1 /*
   2     net_socket.c -- Handle various kinds of sockets.
   3     Copyright (C) 1998-2005 Ivo Timmermans,
   4                   2000-2006 Guus Sliepen <guus@tinc-vpn.org>
   5
   6     This program is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     This program is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with this program; if not, write to the Free Software
  18     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19
  20     $Id$
  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 #ifdef WSAEINPROGRESS
  38 #define EINPROGRESS WSAEINPROGRESS
  39 #endif
  40
  41 /* Needed on Mac OS/X */
  42 #ifndef SOL_TCP
  43 #define SOL_TCP IPPROTO_TCP
  44 #endif
  45
  46 int addressfamily = AF_UNSPEC;
  47 int maxtimeout = 900;
  48 int seconds_till_retry = 5;
  49
  50 listen_socket_t listen_socket[MAXSOCKETS];
  51 int listen_sockets;
  52
  53 /* Setup sockets */
  54
  55 static void configure_tcp(connection_t *c)
  56 {
  57         int option;
  58
  59 #ifdef O_NONBLOCK
  60         int flags = fcntl(c->socket, F_GETFL);
  61
  62         if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
  63                 logger(LOG_ERR, _("fcntl for %s: %s"), c->hostname, strerror(errno));
  64         }
  65 #endif
  66
  67 #if defined(SOL_TCP) && defined(TCP_NODELAY)
  68         option = 1;
  69         setsockopt(c->socket, SOL_TCP, TCP_NODELAY, &option, sizeof(option));
  70 #endif
  71
  72 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
  73         option = IPTOS_LOWDELAY;
  74         setsockopt(c->socket, SOL_IP, IP_TOS, &option, sizeof(option));
  75 #endif
  76 }
  77
  78 int setup_listen_socket(const sockaddr_t *sa)
  79 {
  80         int nfd;
  81         char *addrstr;
  82         int option;
  83         char *iface;
  84
  85         cp();
  86
  87         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
  88
  89         if(nfd < 0) {
  90                 ifdebug(STATUS) logger(LOG_ERR, _("Creating metasocket failed: %s"), strerror(errno));
  91                 return -1;
  92         }
  93
  94         /* Optimize TCP settings */
  95
  96         option = 1;
  97         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option));
  98
  99         if(get_config_string
 100            (lookup_config(config_tree, "BindToInterface"), &iface)) {
 101 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
 102                 struct ifreq ifr;
 103
 104                 memset(&ifr, 0, sizeof(ifr));
 105                 strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
 106
 107                 if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr))) {
 108                         closesocket(nfd);
 109                         logger(LOG_ERR, _("Can't bind to interface %s: %s"), iface,
 110                                    strerror(errno));
 111                         return -1;
 112                 }
 113 #else
 114                 logger(LOG_WARNING, _("BindToInterface not supported on this platform"));
 115 #endif
 116         }
 117
 118         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 119                 closesocket(nfd);
 120                 addrstr = sockaddr2hostname(sa);
 121                 logger(LOG_ERR, _("Can't bind to %s/tcp: %s"), addrstr,
 122                            strerror(errno));
 123                 free(addrstr);
 124                 return -1;
 125         }
 126
 127         if(listen(nfd, 3)) {
 128                 closesocket(nfd);
 129                 logger(LOG_ERR, _("System call `%s' failed: %s"), "listen",
 130                            strerror(errno));
 131                 return -1;
 132         }
 133
 134         return nfd;
 135 }
 136
 137 int setup_vpn_in_socket(const sockaddr_t *sa)
 138 {
 139         int nfd;
 140         char *addrstr;
 141         int option;
 142
 143         cp();
 144
 145         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 146
 147         if(nfd < 0) {
 148                 logger(LOG_ERR, _("Creating UDP socket failed: %s"), strerror(errno));
 149                 return -1;
 150         }
 151
 152 #ifdef O_NONBLOCK
 153         {
 154                 int flags = fcntl(nfd, F_GETFL);
 155
 156                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
 157                         closesocket(nfd);
 158                         logger(LOG_ERR, _("System call `%s' failed: %s"), "fcntl",
 159                                    strerror(errno));
 160                         return -1;
 161                 }
 162         }
 163 #endif
 164
 165         option = 1;
 166         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option));
 167
 168 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 169         {
 170                 bool choice;
 171
 172                 if(get_config_bool(lookup_config(myself->connection->config_tree, "PMTUDiscovery"), &choice) && choice) {
 173                         option = IP_PMTUDISC_DO;
 174                         setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, &option, sizeof(option));
 175                 }
 176         }
 177 #endif
 178
 179 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 180         {
 181                 bool choice;
 182
 183                 if(get_config_bool(lookup_config(myself->connection->config_tree, "PMTUDiscovery"), &choice) && choice) {
 184                         option = IPV6_PMTUDISC_DO;
 185                         setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, &option, sizeof(option));
 186                 }
 187         }
 188 #endif
 189
 190 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
 191         {
 192                 char *iface;
 193                 struct ifreq ifr;
 194
 195                 if(get_config_string(lookup_config(config_tree, "BindToInterface"), &iface)) {
 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(errno));
 203                                 return -1;
 204                         }
 205                 }
 206         }
 207 #endif
 208
 209         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 210                 closesocket(nfd);
 211                 addrstr = sockaddr2hostname(sa);
 212                 logger(LOG_ERR, _("Can't bind to %s/udp: %s"), addrstr,
 213                            strerror(errno));
 214                 free(addrstr);
 215                 return -1;
 216         }
 217
 218         return nfd;
 219 }
 220
 221 void retry_outgoing(outgoing_t *outgoing)
 222 {
 223         event_t *event;
 224
 225         cp();
 226
 227         outgoing->timeout += 5;
 228
 229         if(outgoing->timeout > maxtimeout)
 230                 outgoing->timeout = maxtimeout;
 231
 232         event = new_event();
 233         event->handler = (event_handler_t) setup_outgoing_connection;
 234         event->time = now + outgoing->timeout;
 235         event->data = outgoing;
 236         event_add(event);
 237
 238         ifdebug(CONNECTIONS) logger(LOG_NOTICE,
 239                            _("Trying to re-establish outgoing connection in %d seconds"),
 240                            outgoing->timeout);
 241 }
 242
 243 void finish_connecting(connection_t *c)
 244 {
 245         cp();
 246
 247         ifdebug(CONNECTIONS) logger(LOG_INFO, _("Connected to %s (%s)"), c->name, c->hostname);
 248
 249         configure_tcp(c);
 250
 251         c->last_ping_time = now;
 252
 253         send_id(c);
 254 }
 255
 256 void do_outgoing_connection(connection_t *c)
 257 {
 258         char *address, *port;
 259         int result;
 260
 261         cp();
 262
 263 begin:
 264         if(!c->outgoing->ai) {
 265                 if(!c->outgoing->cfg) {
 266                         ifdebug(CONNECTIONS) logger(LOG_ERR, _("Could not set up a meta connection to %s"),
 267                                            c->name);
 268                         c->status.remove = true;
 269                         retry_outgoing(c->outgoing);
 270                         return;
 271                 }
 272
 273                 get_config_string(c->outgoing->cfg, &address);
 274
 275                 if(!get_config_string(lookup_config(c->config_tree, "Port"), &port))
 276                         asprintf(&port, "655");
 277
 278                 c->outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 279                 free(address);
 280                 free(port);
 281
 282                 c->outgoing->aip = c->outgoing->ai;
 283                 c->outgoing->cfg = lookup_config_next(c->config_tree, c->outgoing->cfg);
 284         }
 285
 286         if(!c->outgoing->aip) {
 287                 freeaddrinfo(c->outgoing->ai);
 288                 c->outgoing->ai = NULL;
 289                 goto begin;
 290         }
 291
 292         memcpy(&c->address, c->outgoing->aip->ai_addr, c->outgoing->aip->ai_addrlen);
 293         c->outgoing->aip = c->outgoing->aip->ai_next;
 294
 295         if(c->hostname)
 296                 free(c->hostname);
 297
 298         c->hostname = sockaddr2hostname(&c->address);
 299
 300         ifdebug(CONNECTIONS) logger(LOG_INFO, _("Trying to connect to %s (%s)"), c->name,
 301                            c->hostname);
 302
 303         c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 304
 305         if(c->socket == -1) {
 306                 ifdebug(CONNECTIONS) logger(LOG_ERR, _("Creating socket for %s failed: %s"), c->hostname,
 307                                    strerror(errno));
 308
 309                 goto begin;
 310         }
 311
 312         /* Optimize TCP settings */
 313
 314         configure_tcp(c);
 315
 316         /* Connect */
 317
 318         result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 319
 320         if(result == -1) {
 321                 if(errno == EINPROGRESS) {
 322                         c->status.connecting = true;
 323                         return;
 324                 }
 325
 326                 closesocket(c->socket);
 327
 328                 ifdebug(CONNECTIONS) logger(LOG_ERR, _("%s: %s"), c->hostname, strerror(errno));
 329
 330                 goto begin;
 331         }
 332
 333         finish_connecting(c);
 334
 335         return;
 336 }
 337
 338 void setup_outgoing_connection(outgoing_t *outgoing)
 339 {
 340         connection_t *c;
 341         node_t *n;
 342
 343         cp();
 344
 345         n = lookup_node(outgoing->name);
 346
 347         if(n)
 348                 if(n->connection) {
 349                         ifdebug(CONNECTIONS) logger(LOG_INFO, _("Already connected to %s"), outgoing->name);
 350
 351                         n->connection->outgoing = outgoing;
 352                         return;
 353                 }
 354
 355         c = new_connection();
 356         c->name = xstrdup(outgoing->name);
 357         c->outcipher = myself->connection->outcipher;
 358         c->outdigest = myself->connection->outdigest;
 359         c->outmaclength = myself->connection->outmaclength;
 360         c->outcompression = myself->connection->outcompression;
 361
 362         init_configuration(&c->config_tree);
 363         read_connection_config(c);
 364
 365         outgoing->cfg = lookup_config(c->config_tree, "Address");
 366
 367         if(!outgoing->cfg) {
 368                 logger(LOG_ERR, _("No address specified for %s"), c->name);
 369                 free_connection(c);
 370                 free(outgoing->name);
 371                 free(outgoing);
 372                 return;
 373         }
 374
 375         c->outgoing = outgoing;
 376         c->last_ping_time = now;
 377
 378         connection_add(c);
 379
 380         do_outgoing_connection(c);
 381 }
 382
 383 /*
 384   accept a new tcp connect and create a
 385   new connection
 386 */
 387 bool handle_new_meta_connection(int sock)
 388 {
 389         int option;
 390         connection_t *c;
 391         sockaddr_t sa;
 392         int fd;
 393         socklen_t len = sizeof(sa);
 394
 395         cp();
 396
 397         fd = accept(sock, &sa.sa, &len);
 398
 399         if(fd < 0) {
 400                 logger(LOG_ERR, _("Accepting a new connection failed: %s"),
 401                            strerror(errno));
 402                 return false;
 403         }
 404
 405         sockaddrunmap(&sa);
 406
 407         c = new_connection();
 408         c->name = NULL;
 409         c->outcipher = myself->connection->outcipher;
 410         c->outdigest = myself->connection->outdigest;
 411         c->outmaclength = myself->connection->outmaclength;
 412         c->outcompression = myself->connection->outcompression;
 413
 414         c->address = sa;
 415         c->hostname = sockaddr2hostname(&sa);
 416         c->socket = fd;
 417         c->last_ping_time = now;
 418
 419         ifdebug(CONNECTIONS) logger(LOG_NOTICE, _("Connection from %s"), c->hostname);
 420
 421         configure_tcp(c);
 422
 423         connection_add(c);
 424
 425         c->allow_request = ID;
 426         send_id(c);
 427
 428         return true;
 429 }
 430
 431 void try_outgoing_connections(void)
 432 {
 433         static config_t *cfg = NULL;
 434         char *name;
 435         outgoing_t *outgoing;
 436
 437         cp();
 438
 439         for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 440                 get_config_string(cfg, &name);
 441
 442                 if(!check_id(name)) {
 443                         logger(LOG_ERR,
 444                                    _("Invalid name for outgoing connection in %s line %d"),
 445                                    cfg->file, cfg->line);
 446                         free(name);
 447                         continue;
 448                 }
 449
 450                 outgoing = xmalloc_and_zero(sizeof(*outgoing));
 451                 outgoing->name = name;
 452                 setup_outgoing_connection(outgoing);
 453         }
 454 }