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 = 1024 * 1024;
  47 int udp_sndbuf = 1024 * 1024;
  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 #ifndef DISABLE_LEGACY
 553         c->outcipher = myself->connection->outcipher;
 554         c->outdigest = myself->connection->outdigest;
 555 #endif
 556         c->outmaclength = myself->connection->outmaclength;
 557         c->outcompression = myself->connection->outcompression;
 558         c->last_ping_time = now.tv_sec;
 559
 560         connection_add(c);
 561
 562         io_add(&c->io, handle_meta_io, c, c->socket, IO_READ|IO_WRITE);
 563
 564         return true;
 565 }
 566
 567 // Find edges pointing to this node, and use them to build a list of unique, known addresses.
 568 static struct addrinfo *get_known_addresses(node_t *n) {
 569         struct addrinfo *ai = NULL;
 570
 571         for splay_each(edge_t, e, n->edge_tree) {
 572                 if(!e->reverse)
 573                         continue;
 574
 575                 bool found = false;
 576                 for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
 577                         if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
 578                                 found = true;
 579                                 break;
 580                         }
 581                 }
 582                 if(found)
 583                         continue;
 584
 585                 struct addrinfo *nai = xzalloc(sizeof *nai);
 586                 if(ai)
 587                         ai->ai_next = nai;
 588                 ai = nai;
 589                 ai->ai_family = e->reverse->address.sa.sa_family;
 590                 ai->ai_socktype = SOCK_STREAM;
 591                 ai->ai_protocol = IPPROTO_TCP;
 592                 ai->ai_addrlen = SALEN(e->reverse->address.sa);
 593                 ai->ai_addr = xmalloc(ai->ai_addrlen);
 594                 memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
 595         }
 596
 597         return ai;
 598 }
 599
 600 void setup_outgoing_connection(outgoing_t *outgoing) {
 601         timeout_del(&outgoing->ev);
 602
 603         node_t *n = lookup_node(outgoing->name);
 604
 605         if(n && n->connection) {
 606                 logger(DEBUG_CONNECTIONS, LOG_INFO, "Already connected to %s", outgoing->name);
 607
 608                 n->connection->outgoing = outgoing;
 609                 return;
 610         }
 611
 612         init_configuration(&outgoing->config_tree);
 613         read_host_config(outgoing->config_tree, outgoing->name);
 614         outgoing->cfg = lookup_config(outgoing->config_tree, "Address");
 615
 616         if(!outgoing->cfg) {
 617                 if(n)
 618                         outgoing->aip = outgoing->ai = get_known_addresses(n);
 619                 if(!outgoing->ai) {
 620                         logger(DEBUG_ALWAYS, LOG_ERR, "No address known for %s", outgoing->name);
 621                         return;
 622                 }
 623         }
 624
 625         do_outgoing_connection(outgoing);
 626 }
 627
 628 /*
 629   accept a new tcp connect and create a
 630   new connection
 631 */
 632 void handle_new_meta_connection(void *data, int flags) {
 633         listen_socket_t *l = data;
 634         connection_t *c;
 635         sockaddr_t sa;
 636         int fd;
 637         socklen_t len = sizeof sa;
 638
 639         fd = accept(l->tcp.fd, &sa.sa, &len);
 640
 641         if(fd < 0) {
 642                 logger(DEBUG_ALWAYS, LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 643                 return;
 644         }
 645
 646         sockaddrunmap(&sa);
 647
 648         // Check if we get many connections from the same host
 649
 650         static sockaddr_t prev_sa;
 651         static int tarpit = -1;
 652
 653         if(tarpit >= 0) {
 654                 closesocket(tarpit);
 655                 tarpit = -1;
 656         }
 657
 658         if(!sockaddrcmp_noport(&sa, &prev_sa)) {
 659                 static int samehost_burst;
 660                 static int samehost_burst_time;
 661
 662                 if(now.tv_sec - samehost_burst_time > samehost_burst)
 663                         samehost_burst = 0;
 664                 else
 665                         samehost_burst -= now.tv_sec - samehost_burst_time;
 666
 667                 samehost_burst_time = now.tv_sec;
 668                 samehost_burst++;
 669
 670                 if(samehost_burst > max_connection_burst) {
 671                         tarpit = fd;
 672                         return;
 673                 }
 674         }
 675
 676         memcpy(&prev_sa, &sa, sizeof sa);
 677
 678         // Check if we get many connections from different hosts
 679
 680         static int connection_burst;
 681         static int connection_burst_time;
 682
 683         if(now.tv_sec - connection_burst_time > connection_burst)
 684                 connection_burst = 0;
 685         else
 686                 connection_burst -= now.tv_sec - connection_burst_time;
 687
 688         connection_burst_time = now.tv_sec;
 689         connection_burst++;
 690
 691         if(connection_burst >= max_connection_burst) {
 692                 connection_burst = max_connection_burst;
 693                 tarpit = fd;
 694                 return;
 695         }
 696
 697         // Accept the new connection
 698
 699         c = new_connection();
 700         c->name = xstrdup("<unknown>");
 701 #ifndef DISABLE_LEGACY
 702         c->outcipher = myself->connection->outcipher;
 703         c->outdigest = myself->connection->outdigest;
 704 #endif
 705         c->outmaclength = myself->connection->outmaclength;
 706         c->outcompression = myself->connection->outcompression;
 707
 708         c->address = sa;
 709         c->hostname = sockaddr2hostname(&sa);
 710         c->socket = fd;
 711         c->last_ping_time = now.tv_sec;
 712
 713         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection from %s", c->hostname);
 714
 715         io_add(&c->io, handle_meta_io, c, c->socket, IO_READ);
 716
 717         configure_tcp(c);
 718
 719         connection_add(c);
 720
 721         c->allow_request = ID;
 722         send_id(c);
 723 }
 724
 725 #ifndef HAVE_MINGW
 726 /*
 727   accept a new UNIX socket connection
 728 */
 729 void handle_new_unix_connection(void *data, int flags) {
 730         io_t *io = data;
 731         connection_t *c;
 732         sockaddr_t sa;
 733         int fd;
 734         socklen_t len = sizeof sa;
 735
 736         fd = accept(io->fd, &sa.sa, &len);
 737
 738         if(fd < 0) {
 739                 logger(DEBUG_ALWAYS, LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 740                 return;
 741         }
 742
 743         sockaddrunmap(&sa);
 744
 745         c = new_connection();
 746         c->name = xstrdup("<control>");
 747         c->address = sa;
 748         c->hostname = xstrdup("localhost port unix");
 749         c->socket = fd;
 750         c->last_ping_time = now.tv_sec;
 751
 752         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection from %s", c->hostname);
 753
 754         io_add(&c->io, handle_meta_io, c, c->socket, IO_READ);
 755
 756         connection_add(c);
 757
 758         c->allow_request = ID;
 759
 760         send_id(c);
 761 }
 762 #endif
 763
 764 static void free_outgoing(outgoing_t *outgoing) {
 765         timeout_del(&outgoing->ev);
 766
 767         if(outgoing->ai)
 768                 freeaddrinfo(outgoing->ai);
 769
 770         if(outgoing->config_tree)
 771                 exit_configuration(&outgoing->config_tree);
 772
 773         if(outgoing->name)
 774                 free(outgoing->name);
 775
 776         free(outgoing);
 777 }
 778
 779 void try_outgoing_connections(void) {
 780         /* If there is no outgoing list yet, create one. Otherwise, mark all outgoings as deleted. */
 781
 782         if(!outgoing_list) {
 783                 outgoing_list = list_alloc((list_action_t)free_outgoing);
 784         } else {
 785                 for list_each(outgoing_t, outgoing, outgoing_list)
 786                         outgoing->timeout = -1;
 787         }
 788
 789         /* Make sure there is one outgoing_t in the list for each ConnectTo. */
 790
 791         for(config_t *cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 792                 char *name;
 793                 get_config_string(cfg, &name);
 794
 795                 if(!check_id(name)) {
 796                         logger(DEBUG_ALWAYS, LOG_ERR,
 797                                    "Invalid name for outgoing connection in %s line %d",
 798                                    cfg->file, cfg->line);
 799                         free(name);
 800                         continue;
 801                 }
 802
 803                 if(!strcmp(name, myself->name)) {
 804                         free(name);
 805                         continue;
 806                 }
 807
 808                 bool found = false;
 809
 810                 for list_each(outgoing_t, outgoing, outgoing_list) {
 811                         if(!strcmp(outgoing->name, name)) {
 812                                 found = true;
 813                                 outgoing->timeout = 0;
 814                                 break;
 815                         }
 816                 }
 817
 818                 if(!found) {
 819                         outgoing_t *outgoing = xzalloc(sizeof *outgoing);
 820                         outgoing->name = name;
 821                         list_insert_tail(outgoing_list, outgoing);
 822                         setup_outgoing_connection(outgoing);
 823                 }
 824         }
 825
 826         /* Terminate any connections whose outgoing_t is to be deleted. */
 827
 828         for list_each(connection_t, c, connection_list) {
 829                 if(c->outgoing && c->outgoing->timeout == -1) {
 830                         c->outgoing = NULL;
 831                         logger(DEBUG_CONNECTIONS, LOG_INFO, "No more outgoing connection to %s", c->name);
 832                         terminate_connection(c, c->edge);
 833                 }
 834         }
 835
 836         /* Delete outgoing_ts for which there is no ConnectTo. */
 837
 838         for list_each(outgoing_t, outgoing, outgoing_list)
 839                 if(outgoing->timeout == -1)
 840                         list_delete_node(outgoing_list, node);
 841 }