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

   1 /*
   2     net_socket.c -- Handle various kinds of sockets.
   3     Copyright (C) 2014-2017 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 #ifndef MSG_NOSIGNAL
  40 #define MSG_NOSIGNAL 0
  41 #endif
  42
  43 int addressfamily = AF_UNSPEC;
  44 int seconds_till_retry = 5;
  45 int max_connection_burst = 100;
  46
  47 /* Setup sockets */
  48
  49 static void configure_tcp(connection_t *c) {
  50 #ifdef O_NONBLOCK
  51         int flags = fcntl(c->socket, F_GETFL);
  52
  53         if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
  54                 logger(c->mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "fcntl", strerror(errno));
  55         }
  56
  57 #elif defined(WIN32)
  58         unsigned long arg = 1;
  59
  60         if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
  61                 logger(c->mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
  62         }
  63
  64 #endif
  65
  66 #if defined(SOL_TCP) && defined(TCP_NODELAY)
  67         int nodelay = 1;
  68         setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&nodelay, sizeof(nodelay));
  69 #endif
  70
  71 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
  72         int lowdelay = IPTOS_LOWDELAY;
  73         setsockopt(c->socket, SOL_IP, IP_TOS, (void *)&lowdelay, sizeof(lowdelay));
  74 #endif
  75 }
  76
  77 static bool bind_to_address(meshlink_handle_t *mesh, connection_t *c) {
  78         int s = -1;
  79
  80         for(int i = 0; i < mesh->listen_sockets && mesh->listen_socket[i].bindto; i++) {
  81                 if(mesh->listen_socket[i].sa.sa.sa_family != c->address.sa.sa_family) {
  82                         continue;
  83                 }
  84
  85                 if(s >= 0) {
  86                         return false;
  87                 }
  88
  89                 s = i;
  90         }
  91
  92         if(s < 0) {
  93                 return false;
  94         }
  95
  96         sockaddr_t sa = mesh->listen_socket[s].sa;
  97
  98         if(sa.sa.sa_family == AF_INET) {
  99                 sa.in.sin_port = 0;
 100         } else if(sa.sa.sa_family == AF_INET6) {
 101                 sa.in6.sin6_port = 0;
 102         }
 103
 104         if(bind(c->socket, &sa.sa, SALEN(sa.sa))) {
 105                 logger(mesh, MESHLINK_WARNING, "Can't bind outgoing socket: %s", strerror(errno));
 106                 return false;
 107         }
 108
 109         return true;
 110 }
 111
 112 int setup_listen_socket(const sockaddr_t *sa) {
 113         int nfd;
 114         char *addrstr;
 115         int option;
 116
 117         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 118
 119         if(nfd < 0) {
 120                 logger(NULL, MESHLINK_ERROR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
 121                 return -1;
 122         }
 123
 124 #ifdef FD_CLOEXEC
 125         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 126 #endif
 127
 128         /* Optimize TCP settings */
 129
 130         option = 1;
 131         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
 132
 133 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 134
 135         if(sa->sa.sa_family == AF_INET6) {
 136                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
 137         }
 138
 139 #endif
 140
 141         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 142                 closesocket(nfd);
 143                 addrstr = sockaddr2hostname(sa);
 144                 logger(NULL, MESHLINK_ERROR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
 145                 free(addrstr);
 146                 return -1;
 147         }
 148
 149         if(listen(nfd, 3)) {
 150                 closesocket(nfd);
 151                 logger(NULL, MESHLINK_ERROR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
 152                 return -1;
 153         }
 154
 155         return nfd;
 156 }
 157
 158 int setup_vpn_in_socket(meshlink_handle_t *mesh, const sockaddr_t *sa) {
 159         int nfd;
 160         char *addrstr;
 161         int option;
 162
 163         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 164
 165         if(nfd < 0) {
 166                 logger(mesh, MESHLINK_ERROR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
 167                 return -1;
 168         }
 169
 170 #ifdef FD_CLOEXEC
 171         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 172 #endif
 173
 174 #ifdef O_NONBLOCK
 175         {
 176                 int flags = fcntl(nfd, F_GETFL);
 177
 178                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
 179                         closesocket(nfd);
 180                         logger(mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "fcntl",
 181                                strerror(errno));
 182                         return -1;
 183                 }
 184         }
 185 #elif defined(WIN32)
 186         {
 187                 unsigned long arg = 1;
 188
 189                 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
 190                         closesocket(nfd);
 191                         logger(mesh, MESHLINK_ERROR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
 192                         return -1;
 193                 }
 194         }
 195 #endif
 196
 197         option = 1;
 198         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
 199         setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof(option));
 200
 201 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
 202
 203         if(sa->sa.sa_family == AF_INET6) {
 204                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
 205         }
 206
 207 #endif
 208
 209 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
 210 #define IP_DONTFRAGMENT IP_DONTFRAG
 211 #endif
 212
 213 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 214
 215         if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
 216                 option = IP_PMTUDISC_DO;
 217                 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
 218         }
 219
 220 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
 221
 222         if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
 223                 option = 1;
 224                 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
 225         }
 226
 227 #else
 228 #warning No way to disable IPv4 fragmentation
 229 #endif
 230
 231 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 232
 233         if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
 234                 option = IPV6_PMTUDISC_DO;
 235                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
 236         }
 237
 238 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
 239
 240         if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
 241                 option = 1;
 242                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
 243         }
 244
 245 #else
 246 #warning No way to disable IPv6 fragmentation
 247 #endif
 248
 249         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 250                 closesocket(nfd);
 251                 addrstr = sockaddr2hostname(sa);
 252                 logger(mesh, MESHLINK_ERROR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
 253                 free(addrstr);
 254                 return -1;
 255         }
 256
 257         return nfd;
 258 } /* int setup_vpn_in_socket */
 259
 260 static void retry_outgoing_handler(event_loop_t *loop, void *data) {
 261         meshlink_handle_t *mesh = loop->data;
 262         outgoing_t *outgoing = data;
 263         setup_outgoing_connection(mesh, outgoing);
 264 }
 265
 266 void retry_outgoing(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 267         outgoing->timeout += 5;
 268
 269         if(outgoing->timeout > mesh->maxtimeout) {
 270                 outgoing->timeout = mesh->maxtimeout;
 271         }
 272
 273         timeout_add(&mesh->loop, &outgoing->ev, retry_outgoing_handler, outgoing, &(struct timeval) {
 274                 outgoing->timeout, rand() % 100000
 275         });
 276
 277         logger(mesh, MESHLINK_INFO, "Trying to re-establish outgoing connection in %d seconds", outgoing->timeout);
 278 }
 279
 280 void finish_connecting(meshlink_handle_t *mesh, connection_t *c) {
 281         logger(mesh, MESHLINK_INFO, "Connected to %s", c->name);
 282
 283         c->last_ping_time = mesh->loop.now.tv_sec;
 284         c->status.connecting = false;
 285
 286         send_id(mesh, c);
 287 }
 288
 289 static void handle_meta_write(meshlink_handle_t *mesh, connection_t *c) {
 290         if(c->outbuf.len <= c->outbuf.offset) {
 291                 return;
 292         }
 293
 294         ssize_t outlen = send(c->socket, c->outbuf.data + c->outbuf.offset, c->outbuf.len - c->outbuf.offset, MSG_NOSIGNAL);
 295
 296         if(outlen <= 0) {
 297                 if(!errno || errno == EPIPE) {
 298                         logger(mesh, MESHLINK_INFO, "Connection closed by %s", c->name);
 299                 } else if(sockwouldblock(sockerrno)) {
 300                         logger(mesh, MESHLINK_DEBUG, "Sending %lu bytes to %s would block", (unsigned long)(c->outbuf.len - c->outbuf.offset), c->name);
 301                         return;
 302                 } else {
 303                         logger(mesh, MESHLINK_ERROR, "Could not send %lu bytes of data to %s: %s", (unsigned long)(c->outbuf.len - c->outbuf.offset), c->name, strerror(errno));
 304                 }
 305
 306                 terminate_connection(mesh, c, c->status.active);
 307                 return;
 308         }
 309
 310         buffer_read(&c->outbuf, outlen);
 311
 312         if(!c->outbuf.len) {
 313                 io_set(&mesh->loop, &c->io, IO_READ);
 314         }
 315 }
 316
 317 static void handle_meta_io(event_loop_t *loop, void *data, int flags) {
 318         meshlink_handle_t *mesh = loop->data;
 319         connection_t *c = data;
 320
 321         if(c->status.connecting) {
 322                 c->status.connecting = false;
 323
 324                 int result;
 325                 socklen_t len = sizeof(result);
 326                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&result, &len);
 327
 328                 if(!result) {
 329                         finish_connecting(mesh, c);
 330                 } else {
 331                         logger(mesh, MESHLINK_DEBUG, "Error while connecting to %s: %s", c->name, sockstrerror(result));
 332                         terminate_connection(mesh, c, false);
 333                         return;
 334                 }
 335         }
 336
 337         if(flags & IO_WRITE) {
 338                 handle_meta_write(mesh, c);
 339         } else {
 340                 handle_meta_connection_data(mesh, c);
 341         }
 342 }
 343
 344 // Find edges pointing to this node, and use them to build a list of unique, known addresses.
 345 static struct addrinfo *get_known_addresses(node_t *n) {
 346         struct addrinfo *ai = NULL;
 347
 348         for splay_each(edge_t, e, n->edge_tree) {
 349                 if(!e->reverse) {
 350                         continue;
 351                 }
 352
 353                 bool found = false;
 354
 355                 for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
 356                         if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
 357                                 found = true;
 358                                 break;
 359                         }
 360                 }
 361
 362                 if(found) {
 363                         continue;
 364                 }
 365
 366                 // Create a new struct addrinfo, and put it at the head of the list.
 367                 struct addrinfo *nai = xzalloc(sizeof(*nai) + SALEN(e->reverse->address.sa));
 368                 nai->ai_next = ai;
 369                 ai = nai;
 370
 371                 ai->ai_family = e->reverse->address.sa.sa_family;
 372                 ai->ai_socktype = SOCK_STREAM;
 373                 ai->ai_protocol = IPPROTO_TCP;
 374                 ai->ai_addrlen = SALEN(e->reverse->address.sa);
 375                 ai->ai_addr = (struct sockaddr *)(nai + 1);
 376                 memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
 377         }
 378
 379         return ai;
 380 }
 381
 382 // Free struct addrinfo list from get_known_addresses().
 383 static void free_known_addresses(struct addrinfo *ai) {
 384         for(struct addrinfo *aip = ai, *next; aip; aip = next) {
 385                 next = aip->ai_next;
 386                 free(aip);
 387         }
 388 }
 389
 390 bool do_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 391         char *address, *port, *space;
 392         struct addrinfo *proxyai = NULL;
 393         int result;
 394
 395 begin:
 396
 397         if(!outgoing->ai && !outgoing->nai) {
 398                 if(!outgoing->cfg) {
 399                         logger(mesh, MESHLINK_ERROR, "Could not set up a meta connection to %s", outgoing->name);
 400                         retry_outgoing(mesh, outgoing);
 401                         return false;
 402                 }
 403
 404                 get_config_string(outgoing->cfg, &address);
 405
 406                 space = strchr(address, ' ');
 407
 408                 if(space) {
 409                         port = xstrdup(space + 1);
 410                         *space = 0;
 411                 } else {
 412                         // TODO: Only allow Address statements?
 413                         if(!get_config_string(lookup_config(outgoing->config_tree, "Port"), &port)) {
 414                                 logger(mesh, MESHLINK_ERROR, "No Port known for %s", outgoing->name);
 415                                 retry_outgoing(mesh, outgoing);
 416                                 return false;
 417                         }
 418                 }
 419
 420                 outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 421                 free(address);
 422                 free(port);
 423
 424                 outgoing->aip = outgoing->ai;
 425                 outgoing->cfg = lookup_config_next(outgoing->config_tree, outgoing->cfg);
 426         }
 427
 428         if(!outgoing->aip) {
 429                 if(outgoing->ai) {
 430                         freeaddrinfo(outgoing->ai);
 431                 }
 432
 433                 outgoing->ai = NULL;
 434
 435                 if(outgoing->nai) {
 436                         free_known_addresses(outgoing->nai);
 437                 }
 438
 439                 outgoing->nai = NULL;
 440
 441                 goto begin;
 442         }
 443
 444         connection_t *c = new_connection();
 445         c->outgoing = outgoing;
 446
 447         memcpy(&c->address, outgoing->aip->ai_addr, outgoing->aip->ai_addrlen);
 448         outgoing->aip = outgoing->aip->ai_next;
 449
 450         char *hostname = sockaddr2hostname(&c->address);
 451
 452         logger(mesh, MESHLINK_INFO, "Trying to connect to %s at %s", outgoing->name, hostname);
 453
 454         if(!mesh->proxytype) {
 455                 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 456                 configure_tcp(c);
 457         } else {
 458                 proxyai = str2addrinfo(mesh->proxyhost, mesh->proxyport, SOCK_STREAM);
 459
 460                 if(!proxyai) {
 461                         free_connection(c);
 462                         free(hostname);
 463                         goto begin;
 464                 }
 465
 466                 logger(mesh, MESHLINK_INFO, "Using proxy at %s port %s", mesh->proxyhost, mesh->proxyport);
 467                 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
 468                 configure_tcp(c);
 469         }
 470
 471         if(c->socket == -1) {
 472                 logger(mesh, MESHLINK_ERROR, "Creating socket for %s at %s failed: %s", c->name, c->hostname, sockstrerror(sockerrno));
 473                 free_connection(c);
 474                 free(hostname);
 475                 goto begin;
 476         }
 477
 478         free(hostname);
 479
 480 #ifdef FD_CLOEXEC
 481         fcntl(c->socket, F_SETFD, FD_CLOEXEC);
 482 #endif
 483
 484 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 485
 486         if(c->address.sa.sa_family == AF_INET6) {
 487                 static const int option = 1;
 488                 setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
 489         }
 490
 491 #endif
 492
 493         bind_to_address(mesh, c);
 494
 495         /* Connect */
 496
 497         if(!mesh->proxytype) {
 498                 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 499         } else {
 500                 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
 501                 freeaddrinfo(proxyai);
 502         }
 503
 504         if(result == -1 && !sockinprogress(sockerrno)) {
 505                 logger(mesh, MESHLINK_ERROR, "Could not connect to %s: %s", outgoing->name, sockstrerror(sockerrno));
 506                 free_connection(c);
 507
 508                 goto begin;
 509         }
 510
 511         /* Now that there is a working socket, fill in the rest and register this connection. */
 512
 513         c->status.connecting = true;
 514         c->name = xstrdup(outgoing->name);
 515         c->outcompression = mesh->self->connection->outcompression;
 516         c->last_ping_time = mesh->loop.now.tv_sec;
 517
 518         connection_add(mesh, c);
 519
 520         io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ | IO_WRITE);
 521
 522         return true;
 523 }
 524
 525 void setup_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 526         bool blacklisted = false;
 527         timeout_del(&mesh->loop, &outgoing->ev);
 528
 529         node_t *n = lookup_node(mesh, outgoing->name);
 530
 531         if(n && n->connection) {
 532                 logger(mesh, MESHLINK_INFO, "Already connected to %s", outgoing->name);
 533
 534                 n->connection->outgoing = outgoing;
 535                 return;
 536         }
 537
 538         exit_configuration(&outgoing->config_tree); // discard old configuration if present
 539         init_configuration(&outgoing->config_tree);
 540         read_host_config(mesh, outgoing->config_tree, outgoing->name);
 541         outgoing->cfg = lookup_config(outgoing->config_tree, "Address");
 542
 543         get_config_bool(lookup_config(outgoing->config_tree, "blacklisted"), &blacklisted);
 544
 545         if(blacklisted) {
 546                 return;
 547         }
 548
 549         if(!outgoing->cfg) {
 550                 if(n) {
 551                         outgoing->aip = outgoing->nai = get_known_addresses(n);
 552                 }
 553
 554                 if(!outgoing->nai) {
 555                         logger(mesh, MESHLINK_ERROR, "No address known for %s", outgoing->name);
 556                         return;
 557                 }
 558         }
 559
 560         do_outgoing_connection(mesh, outgoing);
 561 }
 562
 563 /*
 564   accept a new tcp connect and create a
 565   new connection
 566 */
 567 void handle_new_meta_connection(event_loop_t *loop, void *data, int flags) {
 568         (void)flags;
 569         meshlink_handle_t *mesh = loop->data;
 570         listen_socket_t *l = data;
 571         connection_t *c;
 572         sockaddr_t sa;
 573         int fd;
 574         socklen_t len = sizeof(sa);
 575
 576         fd = accept(l->tcp.fd, &sa.sa, &len);
 577
 578         if(fd < 0) {
 579                 if(errno == EINVAL) { // TODO: check if Windows agrees
 580                         event_loop_stop(loop);
 581                         return;
 582                 }
 583
 584                 logger(mesh, MESHLINK_ERROR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 585                 return;
 586         }
 587
 588         sockaddrunmap(&sa);
 589
 590         // Check if we get many connections from the same host
 591
 592         static sockaddr_t prev_sa;
 593         static int tarpit = -1;
 594
 595         if(tarpit >= 0) {
 596                 closesocket(tarpit);
 597                 tarpit = -1;
 598         }
 599
 600         if(!sockaddrcmp_noport(&sa, &prev_sa)) {
 601                 static int samehost_burst;
 602                 static int samehost_burst_time;
 603
 604                 if(mesh->loop.now.tv_sec - samehost_burst_time > samehost_burst) {
 605                         samehost_burst = 0;
 606                 } else {
 607                         samehost_burst -= mesh->loop.now.tv_sec - samehost_burst_time;
 608                 }
 609
 610                 samehost_burst_time = mesh->loop.now.tv_sec;
 611                 samehost_burst++;
 612
 613                 if(samehost_burst > max_connection_burst) {
 614                         tarpit = fd;
 615                         return;
 616                 }
 617         }
 618
 619         memcpy(&prev_sa, &sa, sizeof(sa));
 620
 621         // Check if we get many connections from different hosts
 622
 623         static int connection_burst;
 624         static int connection_burst_time;
 625
 626         if(mesh->loop.now.tv_sec - connection_burst_time > connection_burst) {
 627                 connection_burst = 0;
 628         } else {
 629                 connection_burst -= mesh->loop.now.tv_sec - connection_burst_time;
 630         }
 631
 632         connection_burst_time = mesh->loop.now.tv_sec;
 633         connection_burst++;
 634
 635         if(connection_burst >= max_connection_burst) {
 636                 connection_burst = max_connection_burst;
 637                 tarpit = fd;
 638                 return;
 639         }
 640
 641         // Accept the new connection
 642
 643         c = new_connection();
 644         c->name = xstrdup("<unknown>");
 645         c->outcompression = mesh->self->connection->outcompression;
 646
 647         c->address = sa;
 648         c->socket = fd;
 649         c->last_ping_time = mesh->loop.now.tv_sec;
 650
 651         char *hostname = sockaddr2hostname(&sa);
 652         logger(mesh, MESHLINK_INFO, "Connection from %s", c->hostname);
 653         free(hostname);
 654
 655         io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ);
 656
 657         configure_tcp(c);
 658
 659         connection_add(mesh, c);
 660
 661         c->allow_request = ID;
 662         send_id(mesh, c);
 663 }
 664
 665 static void free_outgoing(outgoing_t *outgoing) {
 666         meshlink_handle_t *mesh = outgoing->mesh;
 667
 668         timeout_del(&mesh->loop, &outgoing->ev);
 669
 670         if(outgoing->ai) {
 671                 freeaddrinfo(outgoing->ai);
 672         }
 673
 674         if(outgoing->nai) {
 675                 free_known_addresses(outgoing->nai);
 676         }
 677
 678         if(outgoing->config_tree) {
 679                 exit_configuration(&outgoing->config_tree);
 680         }
 681
 682         if(outgoing->name) {
 683                 free(outgoing->name);
 684         }
 685
 686         free(outgoing);
 687 }
 688
 689 void try_outgoing_connections(meshlink_handle_t *mesh) {
 690         /* If there is no outgoing list yet, create one. Otherwise, mark all outgoings as deleted. */
 691
 692         if(!mesh->outgoings) {
 693                 mesh->outgoings = list_alloc((list_action_t)free_outgoing);
 694         } else {
 695                 for list_each(outgoing_t, outgoing, mesh->outgoings) {
 696                         outgoing->timeout = -1;
 697                 }
 698         }
 699
 700         /* Make sure there is one outgoing_t in the list for each ConnectTo. */
 701
 702         // TODO: Drop support for ConnectTo since AutoConnect is now always on?
 703         for(config_t *cfg = lookup_config(mesh->config, "ConnectTo"); cfg; cfg = lookup_config_next(mesh->config, cfg)) {
 704                 char *name;
 705                 get_config_string(cfg, &name);
 706
 707                 if(!check_id(name)) {
 708                         logger(mesh, MESHLINK_ERROR,
 709                                "Invalid name for outgoing connection in %s line %d",
 710                                cfg->file, cfg->line);
 711                         free(name);
 712                         continue;
 713                 }
 714
 715                 bool found = false;
 716
 717                 for list_each(outgoing_t, outgoing, mesh->outgoings) {
 718                         if(!strcmp(outgoing->name, name)) {
 719                                 found = true;
 720                                 outgoing->timeout = 0;
 721                                 break;
 722                         }
 723                 }
 724
 725                 if(!found) {
 726                         outgoing_t *outgoing = xzalloc(sizeof(*outgoing));
 727                         outgoing->mesh = mesh;
 728                         outgoing->name = name;
 729                         list_insert_tail(mesh->outgoings, outgoing);
 730                         setup_outgoing_connection(mesh, outgoing);
 731                 }
 732         }
 733
 734         /* Terminate any connections whose outgoing_t is to be deleted. */
 735
 736         for list_each(connection_t, c, mesh->connections) {
 737                 if(c->outgoing && c->outgoing->timeout == -1) {
 738                         c->outgoing = NULL;
 739                         logger(mesh, MESHLINK_INFO, "No more outgoing connection to %s", c->name);
 740                         terminate_connection(mesh, c, c->status.active);
 741                 }
 742         }
 743
 744         /* Delete outgoing_ts for which there is no ConnectTo. */
 745
 746         for list_each(outgoing_t, outgoing, mesh->outgoings)
 747                 if(outgoing->timeout == -1) {
 748                         list_delete_node(mesh->outgoings, node);
 749                 }
 750 }