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                   2000-2014 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 "conf.h"
  26 #include "connection.h"
  27 #include "control_common.h"
  28 #include "list.h"
  29 #include "logger.h"
  30 #include "meta.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 /* 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 int max_connection_burst = 100;
  49
  50 listen_socket_t listen_socket[MAXSOCKETS];
  51 int listen_sockets;
  52 #ifndef HAVE_MINGW
  53 io_t unix_socket;
  54 #endif
  55 list_t *outgoing_list = NULL;
  56
  57 /* Setup sockets */
  58
  59 static void configure_tcp(connection_t *c) {
  60         int option;
  61
  62 #ifdef O_NONBLOCK
  63         int flags = fcntl(c->socket, F_GETFL);
  64
  65         if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
  66                 logger(DEBUG_ALWAYS, LOG_ERR, "fcntl for %s: %s", c->hostname, strerror(errno));
  67         }
  68 #elif defined(WIN32)
  69         unsigned long arg = 1;
  70
  71         if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
  72                 logger(DEBUG_ALWAYS, LOG_ERR, "ioctlsocket for %s: %s", c->hostname, sockstrerror(sockerrno));
  73         }
  74 #endif
  75
  76 #if defined(SOL_TCP) && defined(TCP_NODELAY)
  77         option = 1;
  78         setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&option, sizeof option);
  79 #endif
  80
  81 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
  82         option = IPTOS_LOWDELAY;
  83         setsockopt(c->socket, SOL_IP, IP_TOS, (void *)&option, sizeof option);
  84 #endif
  85 }
  86
  87 static bool bind_to_interface(int sd) {
  88         char *iface;
  89
  90 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  91         struct ifreq ifr;
  92         int status;
  93 #endif /* defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) */
  94
  95         if(!get_config_string (lookup_config (config_tree, "BindToInterface"), &iface))
  96                 return true;
  97
  98 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  99         memset(&ifr, 0, sizeof(ifr));
 100         strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
 101         ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
 102
 103         status = setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr));
 104         if(status) {
 105                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to interface %s: %s", iface,
 106                                 sockstrerror(sockerrno));
 107                 return false;
 108         }
 109 #else /* if !defined(SOL_SOCKET) || !defined(SO_BINDTODEVICE) */
 110         logger(DEBUG_ALWAYS, LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 111 #endif
 112
 113         return true;
 114 }
 115
 116 static bool bind_to_address(connection_t *c) {
 117         int s = -1;
 118
 119         for(int i = 0; i < listen_sockets && listen_socket[i].bindto; i++) {
 120                 if(listen_socket[i].sa.sa.sa_family != c->address.sa.sa_family)
 121                         continue;
 122                 if(s >= 0)
 123                         return false;
 124                 s = i;
 125         }
 126
 127         if(s < 0)
 128                 return false;
 129
 130         sockaddr_t sa = listen_socket[s].sa;
 131         if(sa.sa.sa_family == AF_INET)
 132                 sa.in.sin_port = 0;
 133         else if(sa.sa.sa_family == AF_INET6)
 134                 sa.in6.sin6_port = 0;
 135
 136         if(bind(c->socket, &sa.sa, SALEN(sa.sa))) {
 137                 logger(DEBUG_CONNECTIONS, LOG_WARNING, "Can't bind outgoing socket: %s", sockstrerror(sockerrno));
 138                 return false;
 139         }
 140
 141         return true;
 142 }
 143
 144 int setup_listen_socket(const sockaddr_t *sa) {
 145         int nfd;
 146         char *addrstr;
 147         int option;
 148         char *iface;
 149
 150         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 151
 152         if(nfd < 0) {
 153                 logger(DEBUG_STATUS, LOG_ERR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
 154                 return -1;
 155         }
 156
 157 #ifdef FD_CLOEXEC
 158         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 159 #endif
 160
 161         /* Optimize TCP settings */
 162
 163         option = 1;
 164         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
 165
 166 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 167         if(sa->sa.sa_family == AF_INET6)
 168                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 169 #endif
 170
 171         if(get_config_string
 172            (lookup_config(config_tree, "BindToInterface"), &iface)) {
 173 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
 174                 struct ifreq ifr;
 175
 176                 memset(&ifr, 0, sizeof ifr);
 177                 strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
 178
 179                 if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof ifr)) {
 180                         closesocket(nfd);
 181                         logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to interface %s: %s", iface,
 182                                    sockstrerror(sockerrno));
 183                         return -1;
 184                 }
 185 #else
 186                 logger(DEBUG_ALWAYS, LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 187 #endif
 188         }
 189
 190         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 191                 closesocket(nfd);
 192                 addrstr = sockaddr2hostname(sa);
 193                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
 194                 free(addrstr);
 195                 return -1;
 196         }
 197
 198         if(listen(nfd, 3)) {
 199                 closesocket(nfd);
 200                 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
 201                 return -1;
 202         }
 203
 204         return nfd;
 205 }
 206
 207 int setup_vpn_in_socket(const sockaddr_t *sa) {
 208         int nfd;
 209         char *addrstr;
 210         int option;
 211
 212         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 213
 214         if(nfd < 0) {
 215                 logger(DEBUG_ALWAYS, LOG_ERR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
 216                 return -1;
 217         }
 218
 219 #ifdef FD_CLOEXEC
 220         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 221 #endif
 222
 223 #ifdef O_NONBLOCK
 224         {
 225                 int flags = fcntl(nfd, F_GETFL);
 226
 227                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
 228                         closesocket(nfd);
 229                         logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "fcntl",
 230                                    strerror(errno));
 231                         return -1;
 232                 }
 233         }
 234 #elif defined(WIN32)
 235         {
 236                 unsigned long arg = 1;
 237                 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
 238                         closesocket(nfd);
 239                         logger(DEBUG_ALWAYS, LOG_ERR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
 240                         return -1;
 241                 }
 242         }
 243 #endif
 244
 245         option = 1;
 246         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
 247         setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof option);
 248
 249         if(udp_rcvbuf && setsockopt(nfd, SOL_SOCKET, SO_RCVBUF, (void *)&udp_rcvbuf, sizeof(udp_rcvbuf)))
 250                 logger(DEBUG_ALWAYS, LOG_WARNING, "Can't set UDP SO_RCVBUF to %i: %s", udp_rcvbuf, sockstrerror(sockerrno));
 251
 252         if(udp_sndbuf && setsockopt(nfd, SOL_SOCKET, SO_SNDBUF, (void *)&udp_sndbuf, sizeof(udp_sndbuf)))
 253                 logger(DEBUG_ALWAYS, LOG_WARNING, "Can't set UDP SO_SNDBUF to %i: %s", udp_sndbuf, sockstrerror(sockerrno));
 254
 255 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
 256         if(sa->sa.sa_family == AF_INET6)
 257                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 258 #endif
 259
 260 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
 261 #define IP_DONTFRAGMENT IP_DONTFRAG
 262 #endif
 263
 264 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 265         if(myself->options & OPTION_PMTU_DISCOVERY) {
 266                 option = IP_PMTUDISC_DO;
 267                 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
 268         }
 269 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
 270         if(myself->options & OPTION_PMTU_DISCOVERY) {
 271                 option = 1;
 272                 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
 273         }
 274 #endif
 275
 276 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 277         if(myself->options & OPTION_PMTU_DISCOVERY) {
 278                 option = IPV6_PMTUDISC_DO;
 279                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
 280         }
 281 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
 282         if(myself->options & OPTION_PMTU_DISCOVERY) {
 283                 option = 1;
 284                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
 285         }
 286 #endif
 287
 288         if (!bind_to_interface(nfd)) {
 289                 closesocket(nfd);
 290                 return -1;
 291         }
 292
 293         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 294                 closesocket(nfd);
 295                 addrstr = sockaddr2hostname(sa);
 296                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
 297                 free(addrstr);
 298                 return -1;
 299         }
 300
 301         return nfd;
 302 } /* int setup_vpn_in_socket */
 303
 304 static void retry_outgoing_handler(void *data) {
 305         setup_outgoing_connection(data);
 306 }
 307
 308 void retry_outgoing(outgoing_t *outgoing) {
 309         outgoing->timeout += 5;
 310
 311         if(outgoing->timeout > maxtimeout)
 312                 outgoing->timeout = maxtimeout;
 313
 314         timeout_add(&outgoing->ev, retry_outgoing_handler, outgoing, &(struct timeval){outgoing->timeout, rand() % 100000});
 315
 316         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Trying to re-establish outgoing connection in %d seconds", outgoing->timeout);
 317 }
 318
 319 void finish_connecting(connection_t *c) {
 320         logger(DEBUG_CONNECTIONS, LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 321
 322         c->last_ping_time = now.tv_sec;
 323         c->status.connecting = false;
 324
 325         send_id(c);
 326 }
 327
 328 static void do_outgoing_pipe(connection_t *c, char *command) {
 329 #ifndef HAVE_MINGW
 330         int fd[2];
 331
 332         if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd)) {
 333                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not create socketpair: %s", sockstrerror(sockerrno));
 334                 return;
 335         }
 336
 337         if(fork()) {
 338                 c->socket = fd[0];
 339                 close(fd[1]);
 340                 logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Using proxy %s", command);
 341                 return;
 342         }
 343
 344         close(0);
 345         close(1);
 346         close(fd[0]);
 347         dup2(fd[1], 0);
 348         dup2(fd[1], 1);
 349         close(fd[1]);
 350
 351         // Other filedescriptors should be closed automatically by CLOEXEC
 352
 353         char *host = NULL;
 354         char *port = NULL;
 355
 356         sockaddr2str(&c->address, &host, &port);
 357         setenv("REMOTEADDRESS", host, true);
 358         setenv("REMOTEPORT", port, true);
 359         setenv("NODE", c->name, true);
 360         setenv("NAME", myself->name, true);
 361         if(netname)
 362                 setenv("NETNAME", netname, true);
 363
 364         int result = system(command);
 365         if(result < 0)
 366                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not execute %s: %s", command, strerror(errno));
 367         else if(result)
 368                 logger(DEBUG_ALWAYS, LOG_ERR, "%s exited with non-zero status %d", command, result);
 369         exit(result);
 370 #else
 371         logger(DEBUG_ALWAYS, LOG_ERR, "Proxy type exec not supported on this platform!");
 372         return;
 373 #endif
 374 }
 375
 376 static void handle_meta_write(connection_t *c) {
 377         if(c->outbuf.len <= c->outbuf.offset)
 378                 return;
 379
 380         ssize_t outlen = send(c->socket, c->outbuf.data + c->outbuf.offset, c->outbuf.len - c->outbuf.offset, 0);
 381         if(outlen <= 0) {
 382                 if(!sockerrno || sockerrno == EPIPE) {
 383                         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection closed by %s (%s)", c->name, c->hostname);
 384                 } else if(sockwouldblock(sockerrno)) {
 385                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Sending %d bytes to %s (%s) would block", c->outbuf.len - c->outbuf.offset, c->name, c->hostname);
 386                         return;
 387                 } else {
 388                         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));
 389                 }
 390
 391                 terminate_connection(c, c->status.active);
 392                 return;
 393         }
 394
 395         buffer_read(&c->outbuf, outlen);
 396         if(!c->outbuf.len)
 397                 io_set(&c->io, IO_READ);
 398 }
 399
 400 static void handle_meta_io(void *data, int flags) {
 401         connection_t *c = data;
 402
 403         if(c->status.connecting) {
 404                 /* The event loop does not protect against spurious events. Verify that we are actually connected. */
 405                 if (connect(c->socket, &c->address.sa, sizeof(c->address)) == 0)
 406                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Error while connecting to %s (%s): redundant connect() unexpectedly succeeded", c->name, c->hostname);
 407                 else if (!sockisconn(sockerrno)) {
 408                         if (!sockalready(sockerrno)) {
 409                                 logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Error while checking connection status for %s (%s): %s", c->name, c->hostname, sockstrerror(sockerrno));
 410                                 terminate_connection(c, false);
 411                         }
 412                         return;
 413                 }
 414
 415                 c->status.connecting = false;
 416
 417                 int result;
 418                 socklen_t len = sizeof result;
 419                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&result, &len);
 420
 421                 if(!result)
 422                         finish_connecting(c);
 423                 else {
 424                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Error while connecting to %s (%s): %s", c->name, c->hostname, sockstrerror(result));
 425                         terminate_connection(c, false);
 426                         return;
 427                 }
 428         }
 429
 430         if(flags & IO_WRITE)
 431                 handle_meta_write(c);
 432         else
 433                 handle_meta_connection_data(c);
 434 }
 435
 436 bool do_outgoing_connection(outgoing_t *outgoing) {
 437         char *address, *port, *space;
 438         struct addrinfo *proxyai = NULL;
 439         int result;
 440
 441 begin:
 442         if(!outgoing->ai) {
 443                 if(!outgoing->cfg) {
 444                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not set up a meta connection to %s", outgoing->name);
 445                         retry_outgoing(outgoing);
 446                         return false;
 447                 }
 448
 449                 get_config_string(outgoing->cfg, &address);
 450
 451                 space = strchr(address, ' ');
 452                 if(space) {
 453                         port = xstrdup(space + 1);
 454                         *space = 0;
 455                 } else {
 456                         if(!get_config_string(lookup_config(outgoing->config_tree, "Port"), &port))
 457                                 port = xstrdup("655");
 458                 }
 459
 460                 outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 461                 free(address);
 462                 free(port);
 463
 464                 outgoing->aip = outgoing->ai;
 465                 outgoing->cfg = lookup_config_next(outgoing->config_tree, outgoing->cfg);
 466         }
 467
 468         if(!outgoing->aip) {
 469                 if(outgoing->ai)
 470                         freeaddrinfo(outgoing->ai);
 471                 outgoing->ai = NULL;
 472                 goto begin;
 473         }
 474
 475         connection_t *c = new_connection();
 476         c->outgoing = outgoing;
 477
 478         memcpy(&c->address, outgoing->aip->ai_addr, outgoing->aip->ai_addrlen);
 479         outgoing->aip = outgoing->aip->ai_next;
 480
 481         c->hostname = sockaddr2hostname(&c->address);
 482
 483         logger(DEBUG_CONNECTIONS, LOG_INFO, "Trying to connect to %s (%s)", outgoing->name, c->hostname);
 484
 485         if(!proxytype) {
 486                 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 487                 configure_tcp(c);
 488         } else if(proxytype == PROXY_EXEC) {
 489                 do_outgoing_pipe(c, proxyhost);
 490         } else {
 491                 proxyai = str2addrinfo(proxyhost, proxyport, SOCK_STREAM);
 492                 if(!proxyai) {
 493                         free_connection(c);
 494                         goto begin;
 495                 }
 496                 logger(DEBUG_CONNECTIONS, LOG_INFO, "Using proxy at %s port %s", proxyhost, proxyport);
 497                 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
 498                 configure_tcp(c);
 499         }
 500
 501         if(c->socket == -1) {
 502                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
 503                 free_connection(c);
 504                 goto begin;
 505         }
 506
 507 #ifdef FD_CLOEXEC
 508         fcntl(c->socket, F_SETFD, FD_CLOEXEC);
 509 #endif
 510
 511         if(proxytype != PROXY_EXEC) {
 512 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 513                 int option = 1;
 514                 if(c->address.sa.sa_family == AF_INET6)
 515                         setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 516 #endif
 517
 518                 bind_to_interface(c->socket);
 519                 bind_to_address(c);
 520         }
 521
 522         /* Connect */
 523
 524         if(!proxytype) {
 525                 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 526         } else if(proxytype == PROXY_EXEC) {
 527                 result = 0;
 528         } else {
 529                 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
 530                 freeaddrinfo(proxyai);
 531         }
 532
 533         if(result == -1 && !sockinprogress(sockerrno)) {
 534                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not connect to %s (%s): %s", outgoing->name, c->hostname, sockstrerror(sockerrno));
 535                 free_connection(c);
 536
 537                 goto begin;
 538         }
 539
 540         /* Now that there is a working socket, fill in the rest and register this connection. */
 541
 542         c->status.connecting = true;
 543         c->name = xstrdup(outgoing->name);
 544         c->outcipher = myself->connection->outcipher;
 545         c->outdigest = myself->connection->outdigest;
 546         c->outmaclength = myself->connection->outmaclength;
 547         c->outcompression = myself->connection->outcompression;
 548         c->last_ping_time = now.tv_sec;
 549
 550         connection_add(c);
 551
 552         io_add(&c->io, handle_meta_io, c, c->socket, IO_READ|IO_WRITE);
 553
 554         return true;
 555 }
 556
 557 // Find edges pointing to this node, and use them to build a list of unique, known addresses.
 558 static struct addrinfo *get_known_addresses(node_t *n) {
 559         struct addrinfo *ai = NULL;
 560
 561         for splay_each(edge_t, e, n->edge_tree) {
 562                 if(!e->reverse)
 563                         continue;
 564
 565                 bool found = false;
 566                 for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
 567                         if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
 568                                 found = true;
 569                                 break;
 570                         }
 571                 }
 572                 if(found)
 573                         continue;
 574
 575                 struct addrinfo *nai = xzalloc(sizeof *nai);
 576                 if(ai)
 577                         ai->ai_next = nai;
 578                 ai = nai;
 579                 ai->ai_family = e->reverse->address.sa.sa_family;
 580                 ai->ai_socktype = SOCK_STREAM;
 581                 ai->ai_protocol = IPPROTO_TCP;
 582                 ai->ai_addrlen = SALEN(e->reverse->address.sa);
 583                 ai->ai_addr = xmalloc(ai->ai_addrlen);
 584                 memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
 585         }
 586
 587         return ai;
 588 }
 589
 590 void setup_outgoing_connection(outgoing_t *outgoing) {
 591         timeout_del(&outgoing->ev);
 592
 593         node_t *n = lookup_node(outgoing->name);
 594
 595         if(n && n->connection) {
 596                 logger(DEBUG_CONNECTIONS, LOG_INFO, "Already connected to %s", outgoing->name);
 597
 598                 n->connection->outgoing = outgoing;
 599                 return;
 600         }
 601
 602         init_configuration(&outgoing->config_tree);
 603         read_host_config(outgoing->config_tree, outgoing->name);
 604         outgoing->cfg = lookup_config(outgoing->config_tree, "Address");
 605
 606         if(!outgoing->cfg) {
 607                 if(n)
 608                         outgoing->aip = outgoing->ai = get_known_addresses(n);
 609                 if(!outgoing->ai) {
 610                         logger(DEBUG_ALWAYS, LOG_ERR, "No address known for %s", outgoing->name);
 611                         return;
 612                 }
 613         }
 614
 615         do_outgoing_connection(outgoing);
 616 }
 617
 618 /*
 619   accept a new tcp connect and create a
 620   new connection
 621 */
 622 void handle_new_meta_connection(void *data, int flags) {
 623         listen_socket_t *l = data;
 624         connection_t *c;
 625         sockaddr_t sa;
 626         int fd;
 627         socklen_t len = sizeof sa;
 628
 629         fd = accept(l->tcp.fd, &sa.sa, &len);
 630
 631         if(fd < 0) {
 632                 logger(DEBUG_ALWAYS, LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 633                 return;
 634         }
 635
 636         sockaddrunmap(&sa);
 637
 638         // Check if we get many connections from the same host
 639
 640         static sockaddr_t prev_sa;
 641         static int tarpit = -1;
 642
 643         if(tarpit >= 0) {
 644                 closesocket(tarpit);
 645                 tarpit = -1;
 646         }
 647
 648         if(!sockaddrcmp_noport(&sa, &prev_sa)) {
 649                 static int samehost_burst;
 650                 static int samehost_burst_time;
 651
 652                 if(now.tv_sec - samehost_burst_time > samehost_burst)
 653                         samehost_burst = 0;
 654                 else
 655                         samehost_burst -= now.tv_sec - samehost_burst_time;
 656
 657                 samehost_burst_time = now.tv_sec;
 658                 samehost_burst++;
 659
 660                 if(samehost_burst > max_connection_burst) {
 661                         tarpit = fd;
 662                         return;
 663                 }
 664         }
 665
 666         memcpy(&prev_sa, &sa, sizeof sa);
 667
 668         // Check if we get many connections from different hosts
 669
 670         static int connection_burst;
 671         static int connection_burst_time;
 672
 673         if(now.tv_sec - connection_burst_time > connection_burst)
 674                 connection_burst = 0;
 675         else
 676                 connection_burst -= now.tv_sec - connection_burst_time;
 677
 678         connection_burst_time = now.tv_sec;
 679         connection_burst++;
 680
 681         if(connection_burst >= max_connection_burst) {
 682                 connection_burst = max_connection_burst;
 683                 tarpit = fd;
 684                 return;
 685         }
 686
 687         // Accept the new connection
 688
 689         c = new_connection();
 690         c->name = xstrdup("<unknown>");
 691         c->outcipher = myself->connection->outcipher;
 692         c->outdigest = myself->connection->outdigest;
 693         c->outmaclength = myself->connection->outmaclength;
 694         c->outcompression = myself->connection->outcompression;
 695
 696         c->address = sa;
 697         c->hostname = sockaddr2hostname(&sa);
 698         c->socket = fd;
 699         c->last_ping_time = now.tv_sec;
 700
 701         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection from %s", c->hostname);
 702
 703         io_add(&c->io, handle_meta_io, c, c->socket, IO_READ);
 704
 705         configure_tcp(c);
 706
 707         connection_add(c);
 708
 709         c->allow_request = ID;
 710         send_id(c);
 711 }
 712
 713 #ifndef HAVE_MINGW
 714 /*
 715   accept a new UNIX socket connection
 716 */
 717 void handle_new_unix_connection(void *data, int flags) {
 718         io_t *io = data;
 719         connection_t *c;
 720         sockaddr_t sa;
 721         int fd;
 722         socklen_t len = sizeof sa;
 723
 724         fd = accept(io->fd, &sa.sa, &len);
 725
 726         if(fd < 0) {
 727                 logger(DEBUG_ALWAYS, LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 728                 return;
 729         }
 730
 731         sockaddrunmap(&sa);
 732
 733         c = new_connection();
 734         c->name = xstrdup("<control>");
 735         c->address = sa;
 736         c->hostname = xstrdup("localhost port unix");
 737         c->socket = fd;
 738         c->last_ping_time = now.tv_sec;
 739
 740         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection from %s", c->hostname);
 741
 742         io_add(&c->io, handle_meta_io, c, c->socket, IO_READ);
 743
 744         connection_add(c);
 745
 746         c->allow_request = ID;
 747
 748         send_id(c);
 749 }
 750 #endif
 751
 752 static void free_outgoing(outgoing_t *outgoing) {
 753         timeout_del(&outgoing->ev);
 754
 755         if(outgoing->ai)
 756                 freeaddrinfo(outgoing->ai);
 757
 758         if(outgoing->config_tree)
 759                 exit_configuration(&outgoing->config_tree);
 760
 761         if(outgoing->name)
 762                 free(outgoing->name);
 763
 764         free(outgoing);
 765 }
 766
 767 void try_outgoing_connections(void) {
 768         /* If there is no outgoing list yet, create one. Otherwise, mark all outgoings as deleted. */
 769
 770         if(!outgoing_list) {
 771                 outgoing_list = list_alloc((list_action_t)free_outgoing);
 772         } else {
 773                 for list_each(outgoing_t, outgoing, outgoing_list)
 774                         outgoing->timeout = -1;
 775         }
 776
 777         /* Make sure there is one outgoing_t in the list for each ConnectTo. */
 778
 779         for(config_t *cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 780                 char *name;
 781                 get_config_string(cfg, &name);
 782
 783                 if(!check_id(name)) {
 784                         logger(DEBUG_ALWAYS, LOG_ERR,
 785                                    "Invalid name for outgoing connection in %s line %d",
 786                                    cfg->file, cfg->line);
 787                         free(name);
 788                         continue;
 789                 }
 790
 791                 bool found = false;
 792
 793                 for list_each(outgoing_t, outgoing, outgoing_list) {
 794                         if(!strcmp(outgoing->name, name)) {
 795                                 found = true;
 796                                 outgoing->timeout = 0;
 797                                 break;
 798                         }
 799                 }
 800
 801                 if(!found) {
 802                         outgoing_t *outgoing = xzalloc(sizeof *outgoing);
 803                         outgoing->name = name;
 804                         list_insert_tail(outgoing_list, outgoing);
 805                         setup_outgoing_connection(outgoing);
 806                 }
 807         }
 808
 809         /* Terminate any connections whose outgoing_t is to be deleted. */
 810
 811         for list_each(connection_t, c, connection_list) {
 812                 if(c->outgoing && c->outgoing->timeout == -1) {
 813                         c->outgoing = NULL;
 814                         logger(DEBUG_CONNECTIONS, LOG_INFO, "No more outgoing connection to %s", c->name);
 815                         terminate_connection(c, c->status.active);
 816                 }
 817         }
 818
 819         /* Delete outgoing_ts for which there is no ConnectTo. */
 820
 821         for list_each(outgoing_t, outgoing, outgoing_list)
 822                 if(outgoing->timeout == -1)
 823                         list_delete_node(outgoing_list, node);
 824 }