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                   2000-2018 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 "address_cache.h"
  26 #include "conf.h"
  27 #include "connection.h"
  28 #include "crypto.h"
  29 #include "list.h"
  30 #include "logger.h"
  31 #include "names.h"
  32 #include "net.h"
  33 #include "netutl.h"
  34 #include "protocol.h"
  35 #include "utils.h"
  36 #include "xalloc.h"
  37
  38 int addressfamily = AF_UNSPEC;
  39 int maxtimeout = 900;
  40 int seconds_till_retry = 5;
  41 int udp_rcvbuf = 1024 * 1024;
  42 int udp_sndbuf = 1024 * 1024;
  43 bool udp_rcvbuf_warnings;
  44 bool udp_sndbuf_warnings;
  45 int max_connection_burst = 10;
  46 int fwmark;
  47
  48 listen_socket_t listen_socket[MAXSOCKETS];
  49 int listen_sockets;
  50 #ifndef HAVE_WINDOWS
  51 io_t unix_socket;
  52 #endif
  53
  54 static void free_outgoing(outgoing_t *outgoing) {
  55         timeout_del(&outgoing->ev);
  56         free(outgoing);
  57 }
  58
  59 list_t outgoing_list = {
  60         .head = NULL,
  61         .tail = NULL,
  62         .count = 0,
  63         .delete = (list_action_t)free_outgoing,
  64 };
  65
  66 /* Setup sockets */
  67
  68 static void configure_tcp(connection_t *c) {
  69         int option;
  70
  71 #ifdef O_NONBLOCK
  72         int flags = fcntl(c->socket, F_GETFL);
  73
  74         if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
  75                 logger(DEBUG_ALWAYS, LOG_ERR, "fcntl for %s fd %d: %s", c->hostname, c->socket, strerror(errno));
  76         }
  77
  78 #elif defined(WIN32)
  79         unsigned long arg = 1;
  80
  81         if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
  82                 logger(DEBUG_ALWAYS, LOG_ERR, "ioctlsocket for %s fd %d: %s", c->hostname, c->socket, sockstrerror(sockerrno));
  83         }
  84
  85 #endif
  86
  87 #if defined(TCP_NODELAY)
  88         option = 1;
  89         setsockopt(c->socket, IPPROTO_TCP, TCP_NODELAY, (void *)&option, sizeof(option));
  90 #endif
  91
  92 #if defined(IP_TOS) && defined(IPTOS_LOWDELAY)
  93         option = IPTOS_LOWDELAY;
  94         setsockopt(c->socket, IPPROTO_IP, IP_TOS, (void *)&option, sizeof(option));
  95 #endif
  96
  97 #if defined(IPV6_TCLASS) && defined(IPTOS_LOWDELAY)
  98         option = IPTOS_LOWDELAY;
  99         setsockopt(c->socket, IPPROTO_IPV6, IPV6_TCLASS, (void *)&option, sizeof(option));
 100 #endif
 101
 102 #if defined(SO_MARK)
 103
 104         if(fwmark) {
 105                 setsockopt(c->socket, SOL_SOCKET, SO_MARK, (void *)&fwmark, sizeof(fwmark));
 106         }
 107
 108 #endif
 109 }
 110
 111 static bool bind_to_interface(int sd) {
 112         char *iface;
 113
 114 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
 115         struct ifreq ifr;
 116         int status;
 117 #endif /* defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) */
 118
 119         if(!get_config_string(lookup_config(&config_tree, "BindToInterface"), &iface)) {
 120                 return true;
 121         }
 122
 123 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
 124         memset(&ifr, 0, sizeof(ifr));
 125         strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
 126         ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
 127
 128         status = setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr));
 129
 130         if(status) {
 131                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to interface %s: %s", iface,
 132                        sockstrerror(sockerrno));
 133                 return false;
 134         }
 135
 136 #else /* if !defined(SOL_SOCKET) || !defined(SO_BINDTODEVICE) */
 137         (void)sd;
 138         logger(DEBUG_ALWAYS, LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 139 #endif
 140
 141         return true;
 142 }
 143
 144 static bool bind_to_address(connection_t *c) {
 145         int s = -1;
 146
 147         for(int i = 0; i < listen_sockets && listen_socket[i].bindto; i++) {
 148                 if(listen_socket[i].sa.sa.sa_family != c->address.sa.sa_family) {
 149                         continue;
 150                 }
 151
 152                 if(s >= 0) {
 153                         return false;
 154                 }
 155
 156                 s = i;
 157         }
 158
 159         if(s < 0) {
 160                 return false;
 161         }
 162
 163         sockaddr_t sa = listen_socket[s].sa;
 164
 165         if(sa.sa.sa_family == AF_INET) {
 166                 sa.in.sin_port = 0;
 167         } else if(sa.sa.sa_family == AF_INET6) {
 168                 sa.in6.sin6_port = 0;
 169         }
 170
 171         if(bind(c->socket, &sa.sa, SALEN(sa.sa))) {
 172                 logger(DEBUG_CONNECTIONS, LOG_WARNING, "Can't bind outgoing socket: %s", sockstrerror(sockerrno));
 173                 return false;
 174         }
 175
 176         return true;
 177 }
 178
 179 static bool try_bind(int nfd, const sockaddr_t *sa, const char *type) {
 180         if(!bind(nfd, &sa->sa, SALEN(sa->sa))) {
 181                 return true;
 182         }
 183
 184         closesocket(nfd);
 185         char *addrstr = sockaddr2hostname(sa);
 186         logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to %s/%s: %s", addrstr, type, sockstrerror(sockerrno));
 187         free(addrstr);
 188         return false;
 189 }
 190
 191 int setup_listen_socket(const sockaddr_t *sa) {
 192         int nfd;
 193         int option;
 194         char *iface;
 195
 196         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 197
 198         if(nfd < 0) {
 199                 logger(DEBUG_STATUS, LOG_ERR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
 200                 return -1;
 201         }
 202
 203 #ifdef FD_CLOEXEC
 204         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 205 #endif
 206
 207         /* Optimize TCP settings */
 208
 209         option = 1;
 210         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
 211
 212 #if defined(IPV6_V6ONLY)
 213
 214         if(sa->sa.sa_family == AF_INET6) {
 215                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
 216         }
 217
 218 #else
 219 #warning IPV6_V6ONLY not defined
 220 #endif
 221
 222 #if defined(SO_MARK)
 223
 224         if(fwmark) {
 225                 setsockopt(nfd, SOL_SOCKET, SO_MARK, (void *)&fwmark, sizeof(fwmark));
 226         }
 227
 228 #endif
 229
 230         if(get_config_string
 231                         (lookup_config(&config_tree, "BindToInterface"), &iface)) {
 232 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
 233                 struct ifreq ifr;
 234
 235                 memset(&ifr, 0, sizeof(ifr));
 236                 strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
 237                 ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
 238
 239                 if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr))) {
 240                         closesocket(nfd);
 241                         logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to interface %s: %s", iface,
 242                                sockstrerror(sockerrno));
 243                         return -1;
 244                 }
 245
 246 #else
 247                 logger(DEBUG_ALWAYS, LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 248 #endif
 249         }
 250
 251         if(!try_bind(nfd, sa, "tcp")) {
 252                 return -1;
 253         }
 254
 255         if(listen(nfd, 3)) {
 256                 closesocket(nfd);
 257                 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
 258                 return -1;
 259         }
 260
 261         return nfd;
 262 }
 263
 264 static void set_udp_buffer(int nfd, int type, const char *name, int size, bool warnings) {
 265         if(!size) {
 266                 return;
 267         }
 268
 269         if(setsockopt(nfd, SOL_SOCKET, type, (void *)&size, sizeof(size))) {
 270                 logger(DEBUG_ALWAYS, LOG_WARNING, "Can't set UDP %s to %i: %s", name, size, sockstrerror(sockerrno));
 271                 return;
 272         }
 273
 274         if(!warnings) {
 275                 return;
 276         }
 277
 278         // The system may cap the requested buffer size.
 279         // Read back the value and check if it is now as requested.
 280         int actual = -1;
 281         socklen_t optlen = sizeof(actual);
 282
 283         if(getsockopt(nfd, SOL_SOCKET, type, (void *)&actual, &optlen)) {
 284                 logger(DEBUG_ALWAYS, LOG_WARNING, "Can't read back UDP %s: %s", name, sockstrerror(sockerrno));
 285         } else if(optlen != sizeof(actual)) {
 286                 logger(DEBUG_ALWAYS, LOG_WARNING, "Can't read back UDP %s: unexpected returned optlen %d", name, (int)optlen);
 287         } else if(actual < size) {
 288                 logger(DEBUG_ALWAYS, LOG_WARNING, "Can't set UDP %s to %i, the system set it to %i instead", name, size, actual);
 289         }
 290 }
 291
 292 int setup_vpn_in_socket(const sockaddr_t *sa) {
 293         int nfd;
 294         int option;
 295
 296         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 297
 298         if(nfd < 0) {
 299                 logger(DEBUG_ALWAYS, LOG_ERR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
 300                 return -1;
 301         }
 302
 303 #ifdef FD_CLOEXEC
 304         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 305 #endif
 306
 307 #ifdef O_NONBLOCK
 308         {
 309                 int flags = fcntl(nfd, F_GETFL);
 310
 311                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
 312                         closesocket(nfd);
 313                         logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "fcntl",
 314                                strerror(errno));
 315                         return -1;
 316                 }
 317         }
 318 #elif defined(WIN32)
 319         {
 320                 unsigned long arg = 1;
 321
 322                 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
 323                         closesocket(nfd);
 324                         logger(DEBUG_ALWAYS, LOG_ERR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
 325                         return -1;
 326                 }
 327         }
 328 #endif
 329
 330         option = 1;
 331         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
 332         setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof(option));
 333
 334         set_udp_buffer(nfd, SO_RCVBUF, "SO_RCVBUF", udp_rcvbuf, udp_rcvbuf_warnings);
 335         set_udp_buffer(nfd, SO_SNDBUF, "SO_SNDBUF", udp_sndbuf, udp_sndbuf_warnings);
 336
 337 #if defined(IPV6_V6ONLY)
 338
 339         if(sa->sa.sa_family == AF_INET6) {
 340                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
 341         }
 342
 343 #endif
 344
 345 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
 346 #define IP_DONTFRAGMENT IP_DONTFRAG
 347 #endif
 348
 349 #if defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 350
 351         if(myself->options & OPTION_PMTU_DISCOVERY) {
 352                 option = IP_PMTUDISC_DO;
 353                 setsockopt(nfd, IPPROTO_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
 354         }
 355
 356 #elif defined(IP_DONTFRAGMENT)
 357
 358         if(myself->options & OPTION_PMTU_DISCOVERY) {
 359                 option = 1;
 360                 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
 361         }
 362
 363 #endif
 364
 365 #if defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 366
 367         if(myself->options & OPTION_PMTU_DISCOVERY) {
 368                 option = IPV6_PMTUDISC_DO;
 369                 setsockopt(nfd, IPPROTO_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
 370         }
 371
 372 #elif defined(IPV6_DONTFRAG)
 373
 374         if(myself->options & OPTION_PMTU_DISCOVERY) {
 375                 option = 1;
 376                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
 377         }
 378
 379 #endif
 380
 381 #if defined(SO_MARK)
 382
 383         if(fwmark) {
 384                 setsockopt(nfd, SOL_SOCKET, SO_MARK, (void *)&fwmark, sizeof(fwmark));
 385         }
 386
 387 #endif
 388
 389         if(!bind_to_interface(nfd)) {
 390                 closesocket(nfd);
 391                 return -1;
 392         }
 393
 394         if(!try_bind(nfd, sa, "udp")) {
 395                 return -1;
 396         }
 397
 398         return nfd;
 399 } /* int setup_vpn_in_socket */
 400
 401 static void retry_outgoing_handler(void *data) {
 402         setup_outgoing_connection(data, true);
 403 }
 404
 405 void retry_outgoing(outgoing_t *outgoing) {
 406         outgoing->timeout += 5;
 407
 408         if(outgoing->timeout > maxtimeout) {
 409                 outgoing->timeout = maxtimeout;
 410         }
 411
 412         timeout_add(&outgoing->ev, retry_outgoing_handler, outgoing, &(struct timeval) {
 413                 outgoing->timeout, jitter()
 414         });
 415
 416         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Trying to re-establish outgoing connection in %d seconds", outgoing->timeout);
 417 }
 418
 419 void finish_connecting(connection_t *c) {
 420         logger(DEBUG_CONNECTIONS, LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 421
 422         c->last_ping_time = now.tv_sec;
 423         c->status.connecting = false;
 424
 425         send_id(c);
 426 }
 427
 428 static void do_outgoing_pipe(connection_t *c, const char *command) {
 429 #ifndef HAVE_WINDOWS
 430         int fd[2];
 431
 432         if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd)) {
 433                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not create socketpair: %s", sockstrerror(sockerrno));
 434                 return;
 435         }
 436
 437         if(fork()) {
 438                 c->socket = fd[0];
 439                 close(fd[1]);
 440                 logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Using proxy %s", command);
 441                 return;
 442         }
 443
 444         close(0);
 445         close(1);
 446         close(fd[0]);
 447         dup2(fd[1], 0);
 448         dup2(fd[1], 1);
 449         close(fd[1]);
 450
 451         // Other filedescriptors should be closed automatically by CLOEXEC
 452
 453         char *host = NULL;
 454         char *port = NULL;
 455
 456         sockaddr2str(&c->address, &host, &port);
 457         setenv("REMOTEADDRESS", host, true);
 458         setenv("REMOTEPORT", port, true);
 459         setenv("NAME", myself->name, true);
 460
 461         if(c->name) {
 462                 setenv("NODE", c->name, true);
 463         }
 464
 465         if(netname) {
 466                 setenv("NETNAME", netname, true);
 467         }
 468
 469         int result = system(command);
 470
 471         if(result < 0) {
 472                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not execute %s: %s", command, strerror(errno));
 473         } else if(result) {
 474                 logger(DEBUG_ALWAYS, LOG_ERR, "%s exited with non-zero status %d", command, result);
 475         }
 476
 477         exit(result);
 478 #else
 479         (void)c;
 480         (void)command;
 481         logger(DEBUG_ALWAYS, LOG_ERR, "Proxy type exec not supported on this platform!");
 482         return;
 483 #endif
 484 }
 485
 486 static void handle_meta_write(connection_t *c) {
 487         if(c->outbuf.len <= c->outbuf.offset) {
 488                 return;
 489         }
 490
 491         ssize_t outlen = send(c->socket, c->outbuf.data + c->outbuf.offset, c->outbuf.len - c->outbuf.offset, 0);
 492
 493         if(outlen <= 0) {
 494                 if(!sockerrno || sockerrno == EPIPE) {
 495                         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection closed by %s (%s)", c->name, c->hostname);
 496                 } else if(sockwouldblock(sockerrno)) {
 497                         logger(DEBUG_META, LOG_DEBUG, "Sending %d bytes to %s (%s) would block", c->outbuf.len - c->outbuf.offset, c->name, c->hostname);
 498                         return;
 499                 } else {
 500                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not send %d bytes of data to %s (%s): %s", c->outbuf.len - c->outbuf.offset, c->name, c->hostname, sockstrerror(sockerrno));
 501                 }
 502
 503                 terminate_connection(c, c->edge);
 504                 return;
 505         }
 506
 507         buffer_read(&c->outbuf, outlen);
 508
 509         if(!c->outbuf.len) {
 510                 io_set(&c->io, IO_READ);
 511         }
 512 }
 513
 514 static void handle_meta_io(void *data, int flags) {
 515         connection_t *c = data;
 516
 517         if(c->status.connecting) {
 518                 /*
 519                    The event loop does not protect against spurious events. Verify that we are actually connected
 520                    by issuing an empty send() call.
 521
 522                    Note that the behavior of send() on potentially unconnected sockets differ between platforms:
 523                    +------------+-----------+-------------+-----------+
 524                    |   Event    |   POSIX   |    Linux    |  Windows  |
 525                    +------------+-----------+-------------+-----------+
 526                    | Spurious   | ENOTCONN  | EWOULDBLOCK | ENOTCONN  |
 527                    | Failed     | ENOTCONN  | (cause)     | ENOTCONN  |
 528                    | Successful | (success) | (success)   | (success) |
 529                    +------------+-----------+-------------+-----------+
 530                 */
 531                 if(send(c->socket, NULL, 0, 0) != 0) {
 532                         if(sockwouldblock(sockerrno)) {
 533                                 return;
 534                         }
 535
 536                         int socket_error;
 537
 538                         if(!socknotconn(sockerrno)) {
 539                                 socket_error = sockerrno;
 540                         } else {
 541                                 socklen_t len = sizeof(socket_error);
 542                                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&socket_error, &len);
 543                         }
 544
 545                         if(socket_error) {
 546                                 logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Error while connecting to %s (%s): %s", c->name, c->hostname, sockstrerror(socket_error));
 547                                 terminate_connection(c, false);
 548                         }
 549
 550                         return;
 551                 }
 552
 553                 c->status.connecting = false;
 554                 finish_connecting(c);
 555         }
 556
 557         if(flags & IO_WRITE) {
 558                 handle_meta_write(c);
 559         } else {
 560                 handle_meta_connection_data(c);
 561         }
 562 }
 563
 564 bool do_outgoing_connection(outgoing_t *outgoing) {
 565         const sockaddr_t *sa;
 566         struct addrinfo *proxyai = NULL;
 567         int result;
 568
 569 begin:
 570         sa = get_recent_address(outgoing->node->address_cache);
 571
 572         if(!sa) {
 573                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not set up a meta connection to %s", outgoing->node->name);
 574                 retry_outgoing(outgoing);
 575                 return false;
 576         }
 577
 578         connection_t *c = new_connection();
 579         c->outgoing = outgoing;
 580         memcpy(&c->address, sa, SALEN(sa->sa));
 581         c->hostname = sockaddr2hostname(&c->address);
 582
 583         logger(DEBUG_CONNECTIONS, LOG_INFO, "Trying to connect to %s (%s)", outgoing->node->name, c->hostname);
 584
 585         if(!proxytype) {
 586                 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 587                 configure_tcp(c);
 588         } else if(proxytype == PROXY_EXEC) {
 589                 do_outgoing_pipe(c, proxyhost);
 590         } else {
 591                 proxyai = str2addrinfo(proxyhost, proxyport, SOCK_STREAM);
 592
 593                 if(!proxyai) {
 594                         free_connection(c);
 595                         goto begin;
 596                 }
 597
 598                 logger(DEBUG_CONNECTIONS, LOG_INFO, "Using proxy at %s port %s", proxyhost, proxyport);
 599                 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
 600                 configure_tcp(c);
 601         }
 602
 603         if(c->socket == -1) {
 604                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
 605                 free_connection(c);
 606                 goto begin;
 607         }
 608
 609 #ifdef FD_CLOEXEC
 610         fcntl(c->socket, F_SETFD, FD_CLOEXEC);
 611 #endif
 612
 613         if(proxytype != PROXY_EXEC) {
 614 #if defined(IPV6_V6ONLY)
 615                 int option = 1;
 616
 617                 if(c->address.sa.sa_family == AF_INET6) {
 618                         setsockopt(c->socket, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
 619                 }
 620
 621 #endif
 622
 623                 bind_to_interface(c->socket);
 624                 bind_to_address(c);
 625         }
 626
 627         /* Connect */
 628
 629         if(!proxytype) {
 630                 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 631         } else if(proxytype == PROXY_EXEC) {
 632                 result = 0;
 633         } else {
 634                 if(!proxyai) {
 635                         abort();
 636                 }
 637
 638                 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
 639                 freeaddrinfo(proxyai);
 640         }
 641
 642         if(result == -1 && !sockinprogress(sockerrno)) {
 643                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not connect to %s (%s): %s", outgoing->node->name, c->hostname, sockstrerror(sockerrno));
 644                 free_connection(c);
 645
 646                 goto begin;
 647         }
 648
 649         /* Now that there is a working socket, fill in the rest and register this connection. */
 650
 651         c->last_ping_time = time(NULL);
 652         c->status.connecting = true;
 653         c->name = xstrdup(outgoing->node->name);
 654         c->outmaclength = myself->connection->outmaclength;
 655         c->last_ping_time = now.tv_sec;
 656
 657         connection_add(c);
 658
 659         io_add(&c->io, handle_meta_io, c, c->socket, IO_READ | IO_WRITE);
 660
 661         return true;
 662 }
 663
 664 void setup_outgoing_connection(outgoing_t *outgoing, bool verbose) {
 665         (void)verbose;
 666         timeout_del(&outgoing->ev);
 667
 668         node_t *n = outgoing->node;
 669
 670         if(!n->address_cache) {
 671                 n->address_cache = open_address_cache(n);
 672         }
 673
 674         if(!n->connection) {
 675                 do_outgoing_connection(outgoing);
 676                 return;
 677         }
 678
 679         logger(DEBUG_CONNECTIONS, LOG_INFO, "Already connected to %s", n->name);
 680
 681         if(n->connection->outgoing) {
 682                 list_delete(&outgoing_list, outgoing);
 683         } else {
 684                 n->connection->outgoing = outgoing;
 685         }
 686 }
 687
 688 static bool check_tarpit(const sockaddr_t *sa, int fd) {
 689         // Check if we get many connections from the same host
 690
 691         static sockaddr_t prev_sa;
 692
 693         if(!sockaddrcmp_noport(sa, &prev_sa)) {
 694                 static time_t samehost_burst;
 695                 static time_t samehost_burst_time;
 696
 697                 if(now.tv_sec - samehost_burst_time > samehost_burst) {
 698                         samehost_burst = 0;
 699                 } else {
 700                         samehost_burst -= now.tv_sec - samehost_burst_time;
 701                 }
 702
 703                 samehost_burst_time = now.tv_sec;
 704                 samehost_burst++;
 705
 706                 if(samehost_burst > max_connection_burst) {
 707                         tarpit(fd);
 708                         return true;
 709                 }
 710         }
 711
 712         memcpy(&prev_sa, &sa, sizeof(sa));
 713
 714         // Check if we get many connections from different hosts
 715
 716         static time_t connection_burst;
 717         static time_t connection_burst_time;
 718
 719         if(now.tv_sec - connection_burst_time > connection_burst) {
 720                 connection_burst = 0;
 721         } else {
 722                 connection_burst -= now.tv_sec - connection_burst_time;
 723         }
 724
 725         connection_burst_time = now.tv_sec;
 726         connection_burst++;
 727
 728         if(connection_burst >= max_connection_burst) {
 729                 connection_burst = max_connection_burst;
 730                 tarpit(fd);
 731                 return true;
 732         }
 733
 734         return false;
 735 }
 736
 737 /*
 738   accept a new tcp connect and create a
 739   new connection
 740 */
 741 void handle_new_meta_connection(void *data, int flags) {
 742         (void)flags;
 743         listen_socket_t *l = data;
 744         connection_t *c;
 745         sockaddr_t sa;
 746         int fd;
 747         socklen_t len = sizeof(sa);
 748
 749         fd = accept(l->tcp.fd, &sa.sa, &len);
 750
 751         if(fd < 0) {
 752                 logger(DEBUG_ALWAYS, LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 753                 return;
 754         }
 755
 756         sockaddrunmap(&sa);
 757
 758         if(!is_local_connection(&sa) && check_tarpit(&sa, fd)) {
 759                 return;
 760         }
 761
 762         // Accept the new connection
 763
 764         c = new_connection();
 765         c->name = xstrdup("<unknown>");
 766         c->outmaclength = myself->connection->outmaclength;
 767
 768         c->address = sa;
 769         c->hostname = sockaddr2hostname(&sa);
 770         c->socket = fd;
 771         c->last_ping_time = now.tv_sec;
 772
 773         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection from %s", c->hostname);
 774
 775         io_add(&c->io, handle_meta_io, c, c->socket, IO_READ);
 776
 777         configure_tcp(c);
 778
 779         connection_add(c);
 780
 781         c->allow_request = ID;
 782 }
 783
 784 #ifndef HAVE_WINDOWS
 785 /*
 786   accept a new UNIX socket connection
 787 */
 788 void handle_new_unix_connection(void *data, int flags) {
 789         (void)flags;
 790         io_t *io = data;
 791         connection_t *c;
 792         sockaddr_t sa;
 793         int fd;
 794         socklen_t len = sizeof(sa);
 795
 796         fd = accept(io->fd, &sa.sa, &len);
 797
 798         if(fd < 0) {
 799                 logger(DEBUG_ALWAYS, LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 800                 return;
 801         }
 802
 803         sockaddrunmap(&sa);
 804
 805         c = new_connection();
 806         c->name = xstrdup("<control>");
 807         c->address = sa;
 808         c->hostname = xstrdup("localhost port unix");
 809         c->socket = fd;
 810         c->last_ping_time = now.tv_sec;
 811
 812         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection from %s", c->hostname);
 813
 814         io_add(&c->io, handle_meta_io, c, c->socket, IO_READ);
 815
 816         connection_add(c);
 817
 818         c->allow_request = ID;
 819 }
 820 #endif
 821
 822 void try_outgoing_connections(void) {
 823         /* If there is no outgoing list yet, create one. Otherwise, mark all outgoings as deleted. */
 824
 825         for list_each(outgoing_t, outgoing, &outgoing_list) {
 826                 outgoing->timeout = -1;
 827         }
 828
 829         /* Make sure there is one outgoing_t in the list for each ConnectTo. */
 830
 831         for(config_t *cfg = lookup_config(&config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(&config_tree, cfg)) {
 832                 char *name;
 833                 get_config_string(cfg, &name);
 834
 835                 if(!check_id(name)) {
 836                         logger(DEBUG_ALWAYS, LOG_ERR,
 837                                "Invalid name for outgoing connection in %s line %d",
 838                                cfg->file, cfg->line);
 839                         free(name);
 840                         continue;
 841                 }
 842
 843                 if(!strcmp(name, myself->name)) {
 844                         free(name);
 845                         continue;
 846                 }
 847
 848                 bool found = false;
 849
 850                 for list_each(outgoing_t, outgoing, &outgoing_list) {
 851                         if(!strcmp(outgoing->node->name, name)) {
 852                                 found = true;
 853                                 outgoing->timeout = 0;
 854                                 break;
 855                         }
 856                 }
 857
 858                 if(!found) {
 859                         outgoing_t *outgoing = xzalloc(sizeof(*outgoing));
 860                         node_t *n = lookup_node(name);
 861
 862                         if(!n) {
 863                                 n = new_node(name);
 864                                 node_add(n);
 865                         }
 866
 867                         outgoing->node = n;
 868                         list_insert_tail(&outgoing_list, outgoing);
 869                         setup_outgoing_connection(outgoing, true);
 870                 }
 871
 872                 free(name);
 873         }
 874
 875         /* Terminate any connections whose outgoing_t is to be deleted. */
 876
 877         for list_each(connection_t, c, &connection_list) {
 878                 if(c->outgoing && c->outgoing->timeout == -1) {
 879                         c->outgoing = NULL;
 880                         logger(DEBUG_CONNECTIONS, LOG_INFO, "No more outgoing connection to %s", c->name);
 881                         terminate_connection(c, c->edge);
 882                 }
 883         }
 884
 885         /* Delete outgoing_ts for which there is no ConnectTo. */
 886
 887         for list_each(outgoing_t, outgoing, &outgoing_list)
 888                 if(outgoing->timeout == -1) {
 889                         list_delete_node(&outgoing_list, node);
 890                 }
 891 }