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                   2000-2014 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->edge);
 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                 /*
 405                    The event loop does not protect against spurious events. Verify that we are actually connected
 406                    by issuing an empty send() call.
 407
 408                    Note that the behavior of send() on potentially unconnected sockets differ between platforms:
 409                    +------------+-----------+-------------+-----------+
 410                    |   Event    |   POSIX   |    Linux    |  Windows  |
 411                    +------------+-----------+-------------+-----------+
 412                    | Spurious   | ENOTCONN  | EWOULDBLOCK | ENOTCONN  |
 413                    | Failed     | ENOTCONN  | (cause)     | ENOTCONN  |
 414                    | Successful | (success) | (success)   | (success) |
 415                    +------------+-----------+-------------+-----------+
 416                 */
 417                 if (send(c->socket, NULL, 0, 0) != 0) {
 418                         if (sockwouldblock(sockerrno))
 419                                 return;
 420                         int socket_error;
 421                         if (!socknotconn(sockerrno))
 422                                 socket_error = sockerrno;
 423                         else {
 424                                 socklen_t len = sizeof socket_error;
 425                                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&socket_error, &len);
 426                         }
 427                         if (socket_error) {
 428                                 logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Error while connecting to %s (%s): %s", c->name, c->hostname, sockstrerror(socket_error));
 429                                 terminate_connection(c, false);
 430                         }
 431                         return;
 432                 }
 433
 434                 c->status.connecting = false;
 435                 finish_connecting(c);
 436         }
 437
 438         if(flags & IO_WRITE)
 439                 handle_meta_write(c);
 440         else
 441                 handle_meta_connection_data(c);
 442 }
 443
 444 bool do_outgoing_connection(outgoing_t *outgoing) {
 445         char *address, *port, *space;
 446         struct addrinfo *proxyai = NULL;
 447         int result;
 448
 449 begin:
 450         if(!outgoing->ai) {
 451                 if(!outgoing->cfg) {
 452                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not set up a meta connection to %s", outgoing->name);
 453                         retry_outgoing(outgoing);
 454                         return false;
 455                 }
 456
 457                 get_config_string(outgoing->cfg, &address);
 458
 459                 space = strchr(address, ' ');
 460                 if(space) {
 461                         port = xstrdup(space + 1);
 462                         *space = 0;
 463                 } else {
 464                         if(!get_config_string(lookup_config(outgoing->config_tree, "Port"), &port))
 465                                 port = xstrdup("655");
 466                 }
 467
 468                 outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 469                 free(address);
 470                 free(port);
 471
 472                 outgoing->aip = outgoing->ai;
 473                 outgoing->cfg = lookup_config_next(outgoing->config_tree, outgoing->cfg);
 474         }
 475
 476         if(!outgoing->aip) {
 477                 if(outgoing->ai)
 478                         freeaddrinfo(outgoing->ai);
 479                 outgoing->ai = NULL;
 480                 goto begin;
 481         }
 482
 483         connection_t *c = new_connection();
 484         c->outgoing = outgoing;
 485
 486         memcpy(&c->address, outgoing->aip->ai_addr, outgoing->aip->ai_addrlen);
 487         outgoing->aip = outgoing->aip->ai_next;
 488
 489         c->hostname = sockaddr2hostname(&c->address);
 490
 491         logger(DEBUG_CONNECTIONS, LOG_INFO, "Trying to connect to %s (%s)", outgoing->name, c->hostname);
 492
 493         if(!proxytype) {
 494                 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 495                 configure_tcp(c);
 496         } else if(proxytype == PROXY_EXEC) {
 497                 do_outgoing_pipe(c, proxyhost);
 498         } else {
 499                 proxyai = str2addrinfo(proxyhost, proxyport, SOCK_STREAM);
 500                 if(!proxyai) {
 501                         free_connection(c);
 502                         goto begin;
 503                 }
 504                 logger(DEBUG_CONNECTIONS, LOG_INFO, "Using proxy at %s port %s", proxyhost, proxyport);
 505                 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
 506                 configure_tcp(c);
 507         }
 508
 509         if(c->socket == -1) {
 510                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
 511                 free_connection(c);
 512                 goto begin;
 513         }
 514
 515 #ifdef FD_CLOEXEC
 516         fcntl(c->socket, F_SETFD, FD_CLOEXEC);
 517 #endif
 518
 519         if(proxytype != PROXY_EXEC) {
 520 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 521                 int option = 1;
 522                 if(c->address.sa.sa_family == AF_INET6)
 523                         setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 524 #endif
 525
 526                 bind_to_interface(c->socket);
 527                 bind_to_address(c);
 528         }
 529
 530         /* Connect */
 531
 532         if(!proxytype) {
 533                 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 534         } else if(proxytype == PROXY_EXEC) {
 535                 result = 0;
 536         } else {
 537                 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
 538                 freeaddrinfo(proxyai);
 539         }
 540
 541         if(result == -1 && !sockinprogress(sockerrno)) {
 542                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not connect to %s (%s): %s", outgoing->name, c->hostname, sockstrerror(sockerrno));
 543                 free_connection(c);
 544
 545                 goto begin;
 546         }
 547
 548         /* Now that there is a working socket, fill in the rest and register this connection. */
 549
 550         c->status.connecting = true;
 551         c->name = xstrdup(outgoing->name);
 552         c->outcipher = myself->connection->outcipher;
 553         c->outdigest = myself->connection->outdigest;
 554         c->outmaclength = myself->connection->outmaclength;
 555         c->outcompression = myself->connection->outcompression;
 556         c->last_ping_time = now.tv_sec;
 557
 558         connection_add(c);
 559
 560         io_add(&c->io, handle_meta_io, c, c->socket, IO_READ|IO_WRITE);
 561
 562         return true;
 563 }
 564
 565 // Find edges pointing to this node, and use them to build a list of unique, known addresses.
 566 static struct addrinfo *get_known_addresses(node_t *n) {
 567         struct addrinfo *ai = NULL;
 568
 569         for splay_each(edge_t, e, n->edge_tree) {
 570                 if(!e->reverse)
 571                         continue;
 572
 573                 bool found = false;
 574                 for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
 575                         if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
 576                                 found = true;
 577                                 break;
 578                         }
 579                 }
 580                 if(found)
 581                         continue;
 582
 583                 struct addrinfo *nai = xzalloc(sizeof *nai);
 584                 if(ai)
 585                         ai->ai_next = nai;
 586                 ai = nai;
 587                 ai->ai_family = e->reverse->address.sa.sa_family;
 588                 ai->ai_socktype = SOCK_STREAM;
 589                 ai->ai_protocol = IPPROTO_TCP;
 590                 ai->ai_addrlen = SALEN(e->reverse->address.sa);
 591                 ai->ai_addr = xmalloc(ai->ai_addrlen);
 592                 memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
 593         }
 594
 595         return ai;
 596 }
 597
 598 void setup_outgoing_connection(outgoing_t *outgoing) {
 599         timeout_del(&outgoing->ev);
 600
 601         node_t *n = lookup_node(outgoing->name);
 602
 603         if(n && n->connection) {
 604                 logger(DEBUG_CONNECTIONS, LOG_INFO, "Already connected to %s", outgoing->name);
 605
 606                 n->connection->outgoing = outgoing;
 607                 return;
 608         }
 609
 610         init_configuration(&outgoing->config_tree);
 611         read_host_config(outgoing->config_tree, outgoing->name);
 612         outgoing->cfg = lookup_config(outgoing->config_tree, "Address");
 613
 614         if(!outgoing->cfg) {
 615                 if(n)
 616                         outgoing->aip = outgoing->ai = get_known_addresses(n);
 617                 if(!outgoing->ai) {
 618                         logger(DEBUG_ALWAYS, LOG_ERR, "No address known for %s", outgoing->name);
 619                         return;
 620                 }
 621         }
 622
 623         do_outgoing_connection(outgoing);
 624 }
 625
 626 /*
 627   accept a new tcp connect and create a
 628   new connection
 629 */
 630 void handle_new_meta_connection(void *data, int flags) {
 631         listen_socket_t *l = data;
 632         connection_t *c;
 633         sockaddr_t sa;
 634         int fd;
 635         socklen_t len = sizeof sa;
 636
 637         fd = accept(l->tcp.fd, &sa.sa, &len);
 638
 639         if(fd < 0) {
 640                 logger(DEBUG_ALWAYS, LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 641                 return;
 642         }
 643
 644         sockaddrunmap(&sa);
 645
 646         // Check if we get many connections from the same host
 647
 648         static sockaddr_t prev_sa;
 649         static int tarpit = -1;
 650
 651         if(tarpit >= 0) {
 652                 closesocket(tarpit);
 653                 tarpit = -1;
 654         }
 655
 656         if(!sockaddrcmp_noport(&sa, &prev_sa)) {
 657                 static int samehost_burst;
 658                 static int samehost_burst_time;
 659
 660                 if(now.tv_sec - samehost_burst_time > samehost_burst)
 661                         samehost_burst = 0;
 662                 else
 663                         samehost_burst -= now.tv_sec - samehost_burst_time;
 664
 665                 samehost_burst_time = now.tv_sec;
 666                 samehost_burst++;
 667
 668                 if(samehost_burst > max_connection_burst) {
 669                         tarpit = fd;
 670                         return;
 671                 }
 672         }
 673
 674         memcpy(&prev_sa, &sa, sizeof sa);
 675
 676         // Check if we get many connections from different hosts
 677
 678         static int connection_burst;
 679         static int connection_burst_time;
 680
 681         if(now.tv_sec - connection_burst_time > connection_burst)
 682                 connection_burst = 0;
 683         else
 684                 connection_burst -= now.tv_sec - connection_burst_time;
 685
 686         connection_burst_time = now.tv_sec;
 687         connection_burst++;
 688
 689         if(connection_burst >= max_connection_burst) {
 690                 connection_burst = max_connection_burst;
 691                 tarpit = fd;
 692                 return;
 693         }
 694
 695         // Accept the new connection
 696
 697         c = new_connection();
 698         c->name = xstrdup("<unknown>");
 699         c->outcipher = myself->connection->outcipher;
 700         c->outdigest = myself->connection->outdigest;
 701         c->outmaclength = myself->connection->outmaclength;
 702         c->outcompression = myself->connection->outcompression;
 703
 704         c->address = sa;
 705         c->hostname = sockaddr2hostname(&sa);
 706         c->socket = fd;
 707         c->last_ping_time = now.tv_sec;
 708
 709         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection from %s", c->hostname);
 710
 711         io_add(&c->io, handle_meta_io, c, c->socket, IO_READ);
 712
 713         configure_tcp(c);
 714
 715         connection_add(c);
 716
 717         c->allow_request = ID;
 718         send_id(c);
 719 }
 720
 721 #ifndef HAVE_MINGW
 722 /*
 723   accept a new UNIX socket connection
 724 */
 725 void handle_new_unix_connection(void *data, int flags) {
 726         io_t *io = data;
 727         connection_t *c;
 728         sockaddr_t sa;
 729         int fd;
 730         socklen_t len = sizeof sa;
 731
 732         fd = accept(io->fd, &sa.sa, &len);
 733
 734         if(fd < 0) {
 735                 logger(DEBUG_ALWAYS, LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 736                 return;
 737         }
 738
 739         sockaddrunmap(&sa);
 740
 741         c = new_connection();
 742         c->name = xstrdup("<control>");
 743         c->address = sa;
 744         c->hostname = xstrdup("localhost port unix");
 745         c->socket = fd;
 746         c->last_ping_time = now.tv_sec;
 747
 748         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection from %s", c->hostname);
 749
 750         io_add(&c->io, handle_meta_io, c, c->socket, IO_READ);
 751
 752         connection_add(c);
 753
 754         c->allow_request = ID;
 755
 756         send_id(c);
 757 }
 758 #endif
 759
 760 static void free_outgoing(outgoing_t *outgoing) {
 761         timeout_del(&outgoing->ev);
 762
 763         if(outgoing->ai)
 764                 freeaddrinfo(outgoing->ai);
 765
 766         if(outgoing->config_tree)
 767                 exit_configuration(&outgoing->config_tree);
 768
 769         if(outgoing->name)
 770                 free(outgoing->name);
 771
 772         free(outgoing);
 773 }
 774
 775 void try_outgoing_connections(void) {
 776         /* If there is no outgoing list yet, create one. Otherwise, mark all outgoings as deleted. */
 777
 778         if(!outgoing_list) {
 779                 outgoing_list = list_alloc((list_action_t)free_outgoing);
 780         } else {
 781                 for list_each(outgoing_t, outgoing, outgoing_list)
 782                         outgoing->timeout = -1;
 783         }
 784
 785         /* Make sure there is one outgoing_t in the list for each ConnectTo. */
 786
 787         for(config_t *cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 788                 char *name;
 789                 get_config_string(cfg, &name);
 790
 791                 if(!check_id(name)) {
 792                         logger(DEBUG_ALWAYS, LOG_ERR,
 793                                    "Invalid name for outgoing connection in %s line %d",
 794                                    cfg->file, cfg->line);
 795                         free(name);
 796                         continue;
 797                 }
 798
 799                 bool found = false;
 800
 801                 for list_each(outgoing_t, outgoing, outgoing_list) {
 802                         if(!strcmp(outgoing->name, name)) {
 803                                 found = true;
 804                                 outgoing->timeout = 0;
 805                                 break;
 806                         }
 807                 }
 808
 809                 if(!found) {
 810                         outgoing_t *outgoing = xzalloc(sizeof *outgoing);
 811                         outgoing->name = name;
 812                         list_insert_tail(outgoing_list, outgoing);
 813                         setup_outgoing_connection(outgoing);
 814                 }
 815         }
 816
 817         /* Terminate any connections whose outgoing_t is to be deleted. */
 818
 819         for list_each(connection_t, c, connection_list) {
 820                 if(c->outgoing && c->outgoing->timeout == -1) {
 821                         c->outgoing = NULL;
 822                         logger(DEBUG_CONNECTIONS, LOG_INFO, "No more outgoing connection to %s", c->name);
 823                         terminate_connection(c, c->edge);
 824                 }
 825         }
 826
 827         /* Delete outgoing_ts for which there is no ConnectTo. */
 828
 829         for list_each(outgoing_t, outgoing, outgoing_list)
 830                 if(outgoing->timeout == -1)
 831                         list_delete_node(outgoing_list, node);
 832 }