git.meshlink.io Git - meshlink/blob - src/net_socket.c

   1 /*
   2     net_socket.c -- Handle various kinds of sockets.
   3     Copyright (C) 2014 Guus Sliepen <guus@meshlink.io>
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License along
  16     with this program; if not, write to the Free Software Foundation, Inc.,
  17     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20 #include "system.h"
  21
  22 #include "conf.h"
  23 #include "connection.h"
  24 #include "list.h"
  25 #include "logger.h"
  26 #include "meshlink_internal.h"
  27 #include "meta.h"
  28 #include "net.h"
  29 #include "netutl.h"
  30 #include "protocol.h"
  31 #include "utils.h"
  32 #include "xalloc.h"
  33
  34 /* Needed on Mac OS/X */
  35 #ifndef SOL_TCP
  36 #define SOL_TCP IPPROTO_TCP
  37 #endif
  38
  39 int addressfamily = AF_UNSPEC;
  40 int maxtimeout = 900;
  41 int seconds_till_retry = 5;
  42 int max_connection_burst = 100;
  43
  44 listen_socket_t listen_socket[MAXSOCKETS];
  45 int listen_sockets;
  46
  47 /* Setup sockets */
  48
  49 static void configure_tcp(connection_t *c) {
  50         int option;
  51
  52 #ifdef O_NONBLOCK
  53         int flags = fcntl(c->socket, F_GETFL);
  54
  55         if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
  56                 logger(DEBUG_ALWAYS, LOG_ERR, "fcntl for %s: %s", c->hostname, strerror(errno));
  57         }
  58 #elif defined(WIN32)
  59         unsigned long arg = 1;
  60
  61         if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
  62                 logger(DEBUG_ALWAYS, LOG_ERR, "ioctlsocket for %s: %s", c->hostname, sockstrerror(sockerrno));
  63         }
  64 #endif
  65
  66 #if defined(SOL_TCP) && defined(TCP_NODELAY)
  67         option = 1;
  68         setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&option, sizeof option);
  69 #endif
  70
  71 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
  72         option = IPTOS_LOWDELAY;
  73         setsockopt(c->socket, SOL_IP, IP_TOS, (void *)&option, sizeof option);
  74 #endif
  75 }
  76
  77 static bool bind_to_address(connection_t *c) {
  78         int s = -1;
  79
  80         for(int i = 0; i < listen_sockets && listen_socket[i].bindto; i++) {
  81                 if(listen_socket[i].sa.sa.sa_family != c->address.sa.sa_family)
  82                         continue;
  83                 if(s >= 0)
  84                         return false;
  85                 s = i;
  86         }
  87
  88         if(s < 0)
  89                 return false;
  90
  91         sockaddr_t sa = listen_socket[s].sa;
  92         if(sa.sa.sa_family == AF_INET)
  93                 sa.in.sin_port = 0;
  94         else if(sa.sa.sa_family == AF_INET6)
  95                 sa.in6.sin6_port = 0;
  96
  97         if(bind(c->socket, &sa.sa, SALEN(sa.sa))) {
  98                 logger(DEBUG_CONNECTIONS, LOG_WARNING, "Can't bind outgoing socket: %s", strerror(errno));
  99                 return false;
 100         }
 101
 102         return true;
 103 }
 104
 105 int setup_listen_socket(const sockaddr_t *sa) {
 106         int nfd;
 107         char *addrstr;
 108         int option;
 109         char *iface;
 110
 111         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 112
 113         if(nfd < 0) {
 114                 logger(DEBUG_STATUS, LOG_ERR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
 115                 return -1;
 116         }
 117
 118 #ifdef FD_CLOEXEC
 119         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 120 #endif
 121
 122         /* Optimize TCP settings */
 123
 124         option = 1;
 125         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
 126
 127 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 128         if(sa->sa.sa_family == AF_INET6)
 129                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 130 #endif
 131
 132         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 133                 closesocket(nfd);
 134                 addrstr = sockaddr2hostname(sa);
 135                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
 136                 free(addrstr);
 137                 return -1;
 138         }
 139
 140         if(listen(nfd, 3)) {
 141                 closesocket(nfd);
 142                 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
 143                 return -1;
 144         }
 145
 146         return nfd;
 147 }
 148
 149 int setup_vpn_in_socket(const sockaddr_t *sa) {
 150         int nfd;
 151         char *addrstr;
 152         int option;
 153
 154         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 155
 156         if(nfd < 0) {
 157                 logger(DEBUG_ALWAYS, LOG_ERR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
 158                 return -1;
 159         }
 160
 161 #ifdef FD_CLOEXEC
 162         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 163 #endif
 164
 165 #ifdef O_NONBLOCK
 166         {
 167                 int flags = fcntl(nfd, F_GETFL);
 168
 169                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
 170                         closesocket(nfd);
 171                         logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "fcntl",
 172                                    strerror(errno));
 173                         return -1;
 174                 }
 175         }
 176 #elif defined(WIN32)
 177         {
 178                 unsigned long arg = 1;
 179                 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
 180                         closesocket(nfd);
 181                         logger(DEBUG_ALWAYS, LOG_ERR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
 182                         return -1;
 183                 }
 184         }
 185 #endif
 186
 187         option = 1;
 188         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
 189         setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof option);
 190
 191 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
 192         if(sa->sa.sa_family == AF_INET6)
 193                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 194 #endif
 195
 196 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
 197 #define IP_DONTFRAGMENT IP_DONTFRAG
 198 #endif
 199
 200 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 201         if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
 202                 option = IP_PMTUDISC_DO;
 203                 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
 204         }
 205 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
 206         if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
 207                 option = 1;
 208                 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
 209         }
 210 #else
 211 #warning No way to disable IPv4 fragmentation
 212 #endif
 213
 214 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 215         if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
 216                 option = IPV6_PMTUDISC_DO;
 217                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
 218         }
 219 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
 220         if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
 221                 option = 1;
 222                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
 223         }
 224 #else
 225 #warning No way to disable IPv6 fragmentation
 226 #endif
 227
 228         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 229                 closesocket(nfd);
 230                 addrstr = sockaddr2hostname(sa);
 231                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
 232                 free(addrstr);
 233                 return -1;
 234         }
 235
 236         return nfd;
 237 } /* int setup_vpn_in_socket */
 238
 239 static void retry_outgoing_handler(void *data) {
 240         setup_outgoing_connection(data);
 241 }
 242
 243 void retry_outgoing(outgoing_t *outgoing) {
 244         outgoing->timeout += 5;
 245
 246         if(outgoing->timeout > maxtimeout)
 247                 outgoing->timeout = maxtimeout;
 248
 249         timeout_add(&outgoing->ev, retry_outgoing_handler, outgoing, &(struct timeval){outgoing->timeout, rand() % 100000});
 250
 251         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Trying to re-establish outgoing connection in %d seconds", outgoing->timeout);
 252 }
 253
 254 void finish_connecting(connection_t *c) {
 255         logger(DEBUG_CONNECTIONS, LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 256
 257         c->last_ping_time = now.tv_sec;
 258         c->status.connecting = false;
 259
 260         send_id(c);
 261 }
 262
 263 static void do_outgoing_pipe(connection_t *c, char *command) {
 264 #ifndef HAVE_MINGW
 265         int fd[2];
 266
 267         if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd)) {
 268                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not create socketpair: %s", strerror(errno));
 269                 return;
 270         }
 271
 272         if(fork()) {
 273                 c->socket = fd[0];
 274                 close(fd[1]);
 275                 logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Using proxy %s", command);
 276                 return;
 277         }
 278
 279         close(0);
 280         close(1);
 281         close(fd[0]);
 282         dup2(fd[1], 0);
 283         dup2(fd[1], 1);
 284         close(fd[1]);
 285
 286         // Other filedescriptors should be closed automatically by CLOEXEC
 287
 288         char *host = NULL;
 289         char *port = NULL;
 290
 291         sockaddr2str(&c->address, &host, &port);
 292         setenv("REMOTEADDRESS", host, true);
 293         setenv("REMOTEPORT", port, true);
 294         setenv("NODE", c->name, true);
 295         setenv("NAME", mesh->self->name, true);
 296
 297         int result = system(command);
 298         if(result < 0)
 299                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not execute %s: %s", command, strerror(errno));
 300         else if(result)
 301                 logger(DEBUG_ALWAYS, LOG_ERR, "%s exited with non-zero status %d", command, result);
 302         exit(result);
 303 #else
 304         logger(DEBUG_ALWAYS, LOG_ERR, "Proxy type exec not supported on this platform!");
 305         return;
 306 #endif
 307 }
 308
 309 static void handle_meta_write(connection_t *c) {
 310         if(c->outbuf.len <= c->outbuf.offset)
 311                 return;
 312
 313         ssize_t outlen = send(c->socket, c->outbuf.data + c->outbuf.offset, c->outbuf.len - c->outbuf.offset, 0);
 314         if(outlen <= 0) {
 315                 if(!errno || errno == EPIPE) {
 316                         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection closed by %s (%s)", c->name, c->hostname);
 317                 } else if(sockwouldblock(sockerrno)) {
 318                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Sending %d bytes to %s (%s) would block", c->outbuf.len - c->outbuf.offset, c->name, c->hostname);
 319                         return;
 320                 } else {
 321                         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, strerror(errno));
 322                 }
 323
 324                 terminate_connection(c, c->status.active);
 325                 return;
 326         }
 327
 328         buffer_read(&c->outbuf, outlen);
 329         if(!c->outbuf.len)
 330                 io_set(&c->io, IO_READ);
 331 }
 332
 333 static void handle_meta_io(void *data, int flags) {
 334         connection_t *c = data;
 335
 336         if(c->status.connecting) {
 337                 c->status.connecting = false;
 338
 339                 int result;
 340                 socklen_t len = sizeof result;
 341                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&result, &len);
 342
 343                 if(!result)
 344                         finish_connecting(c);
 345                 else {
 346                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Error while connecting to %s (%s): %s", c->name, c->hostname, sockstrerror(result));
 347                         terminate_connection(c, false);
 348                         return;
 349                 }
 350         }
 351
 352         if(flags & IO_WRITE)
 353                 handle_meta_write(c);
 354         else
 355                 handle_meta_connection_data(c);
 356 }
 357
 358 bool do_outgoing_connection(outgoing_t *outgoing) {
 359         char *address, *port, *space;
 360         struct addrinfo *proxyai = NULL;
 361         int result;
 362
 363 begin:
 364         if(!outgoing->ai) {
 365                 if(!outgoing->cfg) {
 366                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not set up a meta connection to %s", outgoing->name);
 367                         retry_outgoing(outgoing);
 368                         return false;
 369                 }
 370
 371                 get_config_string(outgoing->cfg, &address);
 372
 373                 space = strchr(address, ' ');
 374                 if(space) {
 375                         port = xstrdup(space + 1);
 376                         *space = 0;
 377                 } else {
 378                         // TODO: Only allow Address statements?
 379                         if(!get_config_string(lookup_config(outgoing->config_tree, "Port"), &port))
 380                                 port = xstrdup("655");
 381                 }
 382
 383                 outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 384                 free(address);
 385                 free(port);
 386
 387                 outgoing->aip = outgoing->ai;
 388                 outgoing->cfg = lookup_config_next(outgoing->config_tree, outgoing->cfg);
 389         }
 390
 391         if(!outgoing->aip) {
 392                 if(outgoing->ai)
 393                         freeaddrinfo(outgoing->ai);
 394                 outgoing->ai = NULL;
 395                 goto begin;
 396         }
 397
 398         connection_t *c = new_connection();
 399         c->outgoing = outgoing;
 400
 401         memcpy(&c->address, outgoing->aip->ai_addr, outgoing->aip->ai_addrlen);
 402         outgoing->aip = outgoing->aip->ai_next;
 403
 404         c->hostname = sockaddr2hostname(&c->address);
 405
 406         logger(DEBUG_CONNECTIONS, LOG_INFO, "Trying to connect to %s (%s)", outgoing->name, c->hostname);
 407
 408         if(!proxytype) {
 409                 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 410                 configure_tcp(c);
 411         } else if(proxytype == PROXY_EXEC) {
 412                 do_outgoing_pipe(c, proxyhost);
 413         } else {
 414                 proxyai = str2addrinfo(proxyhost, proxyport, SOCK_STREAM);
 415                 if(!proxyai) {
 416                         free_connection(c);
 417                         goto begin;
 418                 }
 419                 logger(DEBUG_CONNECTIONS, LOG_INFO, "Using proxy at %s port %s", proxyhost, proxyport);
 420                 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
 421                 configure_tcp(c);
 422         }
 423
 424         if(c->socket == -1) {
 425                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
 426                 free_connection(c);
 427                 goto begin;
 428         }
 429
 430 #ifdef FD_CLOEXEC
 431         fcntl(c->socket, F_SETFD, FD_CLOEXEC);
 432 #endif
 433
 434         if(proxytype != PROXY_EXEC) {
 435 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 436                 int option = 1;
 437                 if(c->address.sa.sa_family == AF_INET6)
 438                         setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 439 #endif
 440
 441                 bind_to_address(c);
 442         }
 443
 444         /* Connect */
 445
 446         if(!proxytype) {
 447                 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 448         } else if(proxytype == PROXY_EXEC) {
 449                 result = 0;
 450         } else {
 451                 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
 452                 freeaddrinfo(proxyai);
 453         }
 454
 455         if(result == -1 && !sockinprogress(sockerrno)) {
 456                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not connect to %s (%s): %s", outgoing->name, c->hostname, sockstrerror(sockerrno));
 457                 free_connection(c);
 458
 459                 goto begin;
 460         }
 461
 462         /* Now that there is a working socket, fill in the rest and register this connection. */
 463
 464         c->status.connecting = true;
 465         c->name = xstrdup(outgoing->name);
 466         c->outcompression = mesh->self->connection->outcompression;
 467         c->last_ping_time = now.tv_sec;
 468
 469         connection_add(c);
 470
 471         io_add(&c->io, handle_meta_io, c, c->socket, IO_READ|IO_WRITE);
 472
 473         return true;
 474 }
 475
 476 // Find edges pointing to this node, and use them to build a list of unique, known addresses.
 477 static struct addrinfo *get_known_addresses(node_t *n) {
 478         struct addrinfo *ai = NULL;
 479
 480         for splay_each(edge_t, e, n->edge_tree) {
 481                 if(!e->reverse)
 482                         continue;
 483
 484                 bool found = false;
 485                 for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
 486                         if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
 487                                 found = true;
 488                                 break;
 489                         }
 490                 }
 491                 if(found)
 492                         continue;
 493
 494                 struct addrinfo *nai = xzalloc(sizeof *nai);
 495                 if(ai)
 496                         ai->ai_next = nai;
 497                 ai = nai;
 498                 ai->ai_family = e->reverse->address.sa.sa_family;
 499                 ai->ai_socktype = SOCK_STREAM;
 500                 ai->ai_protocol = IPPROTO_TCP;
 501                 ai->ai_addrlen = SALEN(e->reverse->address.sa);
 502                 ai->ai_addr = xmalloc(ai->ai_addrlen);
 503                 memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
 504         }
 505
 506         return ai;
 507 }
 508
 509 void setup_outgoing_connection(outgoing_t *outgoing) {
 510         timeout_del(&outgoing->ev);
 511
 512         node_t *n = lookup_node(outgoing->name);
 513
 514         if(n && n->connection) {
 515                 logger(DEBUG_CONNECTIONS, LOG_INFO, "Already connected to %s", outgoing->name);
 516
 517                 n->connection->outgoing = outgoing;
 518                 return;
 519         }
 520
 521         init_configuration(&outgoing->config_tree);
 522         read_host_config(outgoing->config_tree, outgoing->name);
 523         outgoing->cfg = lookup_config(outgoing->config_tree, "Address");
 524
 525         if(!outgoing->cfg) {
 526                 if(n)
 527                         outgoing->aip = outgoing->ai = get_known_addresses(n);
 528                 if(!outgoing->ai) {
 529                         logger(DEBUG_ALWAYS, LOG_ERR, "No address known for %s", outgoing->name);
 530                         return;
 531                 }
 532         }
 533
 534         do_outgoing_connection(outgoing);
 535 }
 536
 537 /*
 538   accept a new tcp connect and create a
 539   new connection
 540 */
 541 void handle_new_meta_connection(void *data, int flags) {
 542         listen_socket_t *l = data;
 543         connection_t *c;
 544         sockaddr_t sa;
 545         int fd;
 546         socklen_t len = sizeof sa;
 547
 548         fd = accept(l->tcp.fd, &sa.sa, &len);
 549
 550         if(fd < 0) {
 551                 logger(DEBUG_ALWAYS, LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 552                 return;
 553         }
 554
 555         sockaddrunmap(&sa);
 556
 557         // Check if we get many connections from the same host
 558
 559         static sockaddr_t prev_sa;
 560         static int tarpit = -1;
 561
 562         if(tarpit >= 0) {
 563                 closesocket(tarpit);
 564                 tarpit = -1;
 565         }
 566
 567         if(!sockaddrcmp_noport(&sa, &prev_sa)) {
 568                 static int samehost_burst;
 569                 static int samehost_burst_time;
 570
 571                 if(now.tv_sec - samehost_burst_time > samehost_burst)
 572                         samehost_burst = 0;
 573                 else
 574                         samehost_burst -= now.tv_sec - samehost_burst_time;
 575
 576                 samehost_burst_time = now.tv_sec;
 577                 samehost_burst++;
 578
 579                 if(samehost_burst > max_connection_burst) {
 580                         tarpit = fd;
 581                         return;
 582                 }
 583         }
 584
 585         memcpy(&prev_sa, &sa, sizeof sa);
 586
 587         // Check if we get many connections from different hosts
 588
 589         static int connection_burst;
 590         static int connection_burst_time;
 591
 592         if(now.tv_sec - connection_burst_time > connection_burst)
 593                 connection_burst = 0;
 594         else
 595                 connection_burst -= now.tv_sec - connection_burst_time;
 596
 597         connection_burst_time = now.tv_sec;
 598         connection_burst++;
 599
 600         if(connection_burst >= max_connection_burst) {
 601                 connection_burst = max_connection_burst;
 602                 tarpit = fd;
 603                 return;
 604         }
 605
 606         // Accept the new connection
 607
 608         c = new_connection();
 609         c->name = xstrdup("<unknown>");
 610         c->outcompression = mesh->self->connection->outcompression;
 611
 612         c->address = sa;
 613         c->hostname = sockaddr2hostname(&sa);
 614         c->socket = fd;
 615         c->last_ping_time = now.tv_sec;
 616
 617         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection from %s", c->hostname);
 618
 619         io_add(&c->io, handle_meta_io, c, c->socket, IO_READ);
 620
 621         configure_tcp(c);
 622
 623         connection_add(c);
 624
 625         c->allow_request = ID;
 626         send_id(c);
 627 }
 628
 629 static void free_outgoing(outgoing_t *outgoing) {
 630         timeout_del(&outgoing->ev);
 631
 632         if(outgoing->ai)
 633                 freeaddrinfo(outgoing->ai);
 634
 635         if(outgoing->config_tree)
 636                 exit_configuration(&outgoing->config_tree);
 637
 638         if(outgoing->name)
 639                 free(outgoing->name);
 640
 641         free(outgoing);
 642 }
 643
 644 void try_outgoing_connections(void) {
 645         /* If there is no outgoing list yet, create one. Otherwise, mark all outgoings as deleted. */
 646
 647         if(!mesh->outgoings) {
 648                 mesh->outgoings = list_alloc((list_action_t)free_outgoing);
 649         } else {
 650                 for list_each(outgoing_t, outgoing, mesh->outgoings)
 651                         outgoing->timeout = -1;
 652         }
 653
 654         /* Make sure there is one outgoing_t in the list for each ConnectTo. */
 655
 656         // TODO: Drop support for ConnectTo since AutoConnect is now always on?
 657         for(config_t *cfg = lookup_config(mesh->config, "ConnectTo"); cfg; cfg = lookup_config_next(mesh->config, cfg)) {
 658                 char *name;
 659                 get_config_string(cfg, &name);
 660
 661                 if(!check_id(name)) {
 662                         logger(DEBUG_ALWAYS, LOG_ERR,
 663                                    "Invalid name for outgoing connection in %s line %d",
 664                                    cfg->file, cfg->line);
 665                         free(name);
 666                         continue;
 667                 }
 668
 669                 bool found = false;
 670
 671                 for list_each(outgoing_t, outgoing, mesh->outgoings) {
 672                         if(!strcmp(outgoing->name, name)) {
 673                                 found = true;
 674                                 outgoing->timeout = 0;
 675                                 break;
 676                         }
 677                 }
 678
 679                 if(!found) {
 680                         outgoing_t *outgoing = xzalloc(sizeof *outgoing);
 681                         outgoing->name = name;
 682                         list_insert_tail(mesh->outgoings, outgoing);
 683                         setup_outgoing_connection(outgoing);
 684                 }
 685         }
 686
 687         /* Terminate any connections whose outgoing_t is to be deleted. */
 688
 689         for list_each(connection_t, c, mesh->connections) {
 690                 if(c->outgoing && c->outgoing->timeout == -1) {
 691                         c->outgoing = NULL;
 692                         logger(DEBUG_CONNECTIONS, LOG_INFO, "No more outgoing connection to %s", c->name);
 693                         terminate_connection(c, c->status.active);
 694                 }
 695         }
 696
 697         /* Delete outgoing_ts for which there is no ConnectTo. */
 698
 699         for list_each(outgoing_t, outgoing, mesh->outgoings)
 700                 if(outgoing->timeout == -1)
 701                         list_delete_node(mesh->outgoings, node);
 702 }