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 seconds_till_retry = 5;
  41 int max_connection_burst = 100;
  42
  43 /* Setup sockets */
  44
  45 static void configure_tcp(connection_t *c) {
  46         int option;
  47
  48 #ifdef O_NONBLOCK
  49         int flags = fcntl(c->socket, F_GETFL);
  50
  51         if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
  52                 logger(DEBUG_ALWAYS, LOG_ERR, "fcntl for %s: %s", c->hostname, strerror(errno));
  53         }
  54 #elif defined(WIN32)
  55         unsigned long arg = 1;
  56
  57         if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
  58                 logger(DEBUG_ALWAYS, LOG_ERR, "ioctlsocket for %s: %s", c->hostname, sockstrerror(sockerrno));
  59         }
  60 #endif
  61
  62 #if defined(SOL_TCP) && defined(TCP_NODELAY)
  63         option = 1;
  64         setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&option, sizeof option);
  65 #endif
  66
  67 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
  68         option = IPTOS_LOWDELAY;
  69         setsockopt(c->socket, SOL_IP, IP_TOS, (void *)&option, sizeof option);
  70 #endif
  71 }
  72
  73 static bool bind_to_address(meshlink_handle_t *mesh, connection_t *c) {
  74         int s = -1;
  75
  76         for(int i = 0; i < mesh->listen_sockets && mesh->listen_socket[i].bindto; i++) {
  77                 if(mesh->listen_socket[i].sa.sa.sa_family != c->address.sa.sa_family)
  78                         continue;
  79                 if(s >= 0)
  80                         return false;
  81                 s = i;
  82         }
  83
  84         if(s < 0)
  85                 return false;
  86
  87         sockaddr_t sa = mesh->listen_socket[s].sa;
  88         if(sa.sa.sa_family == AF_INET)
  89                 sa.in.sin_port = 0;
  90         else if(sa.sa.sa_family == AF_INET6)
  91                 sa.in6.sin6_port = 0;
  92
  93         if(bind(c->socket, &sa.sa, SALEN(sa.sa))) {
  94                 logger(DEBUG_CONNECTIONS, LOG_WARNING, "Can't bind outgoing socket: %s", strerror(errno));
  95                 return false;
  96         }
  97
  98         return true;
  99 }
 100
 101 int setup_listen_socket(const sockaddr_t *sa) {
 102         int nfd;
 103         char *addrstr;
 104         int option;
 105         char *iface;
 106
 107         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 108
 109         if(nfd < 0) {
 110                 logger(DEBUG_STATUS, LOG_ERR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
 111                 return -1;
 112         }
 113
 114 #ifdef FD_CLOEXEC
 115         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 116 #endif
 117
 118         /* Optimize TCP settings */
 119
 120         option = 1;
 121         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
 122
 123 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 124         if(sa->sa.sa_family == AF_INET6)
 125                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 126 #endif
 127
 128         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 129                 closesocket(nfd);
 130                 addrstr = sockaddr2hostname(sa);
 131                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
 132                 free(addrstr);
 133                 return -1;
 134         }
 135
 136         if(listen(nfd, 3)) {
 137                 closesocket(nfd);
 138                 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
 139                 return -1;
 140         }
 141
 142         return nfd;
 143 }
 144
 145 int setup_vpn_in_socket(meshlink_handle_t *mesh, const sockaddr_t *sa) {
 146         int nfd;
 147         char *addrstr;
 148         int option;
 149
 150         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 151
 152         if(nfd < 0) {
 153                 logger(DEBUG_ALWAYS, LOG_ERR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
 154                 return -1;
 155         }
 156
 157 #ifdef FD_CLOEXEC
 158         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 159 #endif
 160
 161 #ifdef O_NONBLOCK
 162         {
 163                 int flags = fcntl(nfd, F_GETFL);
 164
 165                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
 166                         closesocket(nfd);
 167                         logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "fcntl",
 168                                    strerror(errno));
 169                         return -1;
 170                 }
 171         }
 172 #elif defined(WIN32)
 173         {
 174                 unsigned long arg = 1;
 175                 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
 176                         closesocket(nfd);
 177                         logger(DEBUG_ALWAYS, LOG_ERR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
 178                         return -1;
 179                 }
 180         }
 181 #endif
 182
 183         option = 1;
 184         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
 185         setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof option);
 186
 187 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
 188         if(sa->sa.sa_family == AF_INET6)
 189                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 190 #endif
 191
 192 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
 193 #define IP_DONTFRAGMENT IP_DONTFRAG
 194 #endif
 195
 196 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 197         if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
 198                 option = IP_PMTUDISC_DO;
 199                 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
 200         }
 201 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
 202         if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
 203                 option = 1;
 204                 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
 205         }
 206 #else
 207 #warning No way to disable IPv4 fragmentation
 208 #endif
 209
 210 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 211         if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
 212                 option = IPV6_PMTUDISC_DO;
 213                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
 214         }
 215 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
 216         if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
 217                 option = 1;
 218                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
 219         }
 220 #else
 221 #warning No way to disable IPv6 fragmentation
 222 #endif
 223
 224         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 225                 closesocket(nfd);
 226                 addrstr = sockaddr2hostname(sa);
 227                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
 228                 free(addrstr);
 229                 return -1;
 230         }
 231
 232         return nfd;
 233 } /* int setup_vpn_in_socket */
 234
 235 static void retry_outgoing_handler(event_loop_t *loop, void *data) {
 236         meshlink_handle_t *mesh = loop->data;
 237         outgoing_t *outgoing = data;
 238         setup_outgoing_connection(mesh, outgoing);
 239 }
 240
 241 void retry_outgoing(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 242         outgoing->timeout += 5;
 243
 244         if(outgoing->timeout > mesh->maxtimeout)
 245                 outgoing->timeout = mesh->maxtimeout;
 246
 247         timeout_add(&mesh->loop, &outgoing->ev, retry_outgoing_handler, outgoing, &(struct timeval){outgoing->timeout, rand() % 100000});
 248
 249         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Trying to re-establish outgoing connection in %d seconds", outgoing->timeout);
 250 }
 251
 252 void finish_connecting(meshlink_handle_t *mesh, connection_t *c) {
 253         logger(DEBUG_CONNECTIONS, LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 254
 255         c->last_ping_time = mesh->loop.now.tv_sec;
 256         c->status.connecting = false;
 257
 258         send_id(mesh, c);
 259 }
 260
 261 static void do_outgoing_pipe(meshlink_handle_t *mesh, connection_t *c, char *command) {
 262 #ifndef HAVE_MINGW
 263         int fd[2];
 264
 265         if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd)) {
 266                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not create socketpair: %s", strerror(errno));
 267                 return;
 268         }
 269
 270         if(fork()) {
 271                 c->socket = fd[0];
 272                 close(fd[1]);
 273                 logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Using proxy %s", command);
 274                 return;
 275         }
 276
 277         close(0);
 278         close(1);
 279         close(fd[0]);
 280         dup2(fd[1], 0);
 281         dup2(fd[1], 1);
 282         close(fd[1]);
 283
 284         // Other filedescriptors should be closed automatically by CLOEXEC
 285
 286         char *host = NULL;
 287         char *port = NULL;
 288
 289         sockaddr2str(&c->address, &host, &port);
 290         setenv("REMOTEADDRESS", host, true);
 291         setenv("REMOTEPORT", port, true);
 292         setenv("NODE", c->name, true);
 293         setenv("NAME", mesh->self->name, true);
 294
 295         int result = system(command);
 296         if(result < 0)
 297                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not execute %s: %s", command, strerror(errno));
 298         else if(result)
 299                 logger(DEBUG_ALWAYS, LOG_ERR, "%s exited with non-zero status %d", command, result);
 300         exit(result);
 301 #else
 302         logger(DEBUG_ALWAYS, LOG_ERR, "Proxy type exec not supported on this platform!");
 303         return;
 304 #endif
 305 }
 306
 307 static void handle_meta_write(meshlink_handle_t *mesh, connection_t *c) {
 308         if(c->outbuf.len <= c->outbuf.offset)
 309                 return;
 310
 311         ssize_t outlen = send(c->socket, c->outbuf.data + c->outbuf.offset, c->outbuf.len - c->outbuf.offset, 0);
 312         if(outlen <= 0) {
 313                 if(!errno || errno == EPIPE) {
 314                         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection closed by %s (%s)", c->name, c->hostname);
 315                 } else if(sockwouldblock(sockerrno)) {
 316                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Sending %d bytes to %s (%s) would block", c->outbuf.len - c->outbuf.offset, c->name, c->hostname);
 317                         return;
 318                 } else {
 319                         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));
 320                 }
 321
 322                 terminate_connection(mesh, c, c->status.active);
 323                 return;
 324         }
 325
 326         buffer_read(&c->outbuf, outlen);
 327         if(!c->outbuf.len)
 328                 io_set(&mesh->loop, &c->io, IO_READ);
 329 }
 330
 331 static void handle_meta_io(event_loop_t *loop, void *data, int flags) {
 332         meshlink_handle_t *mesh = loop->data;
 333         connection_t *c = data;
 334
 335         if(c->status.connecting) {
 336                 c->status.connecting = false;
 337
 338                 int result;
 339                 socklen_t len = sizeof result;
 340                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&result, &len);
 341
 342                 if(!result)
 343                         finish_connecting(mesh, c);
 344                 else {
 345                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Error while connecting to %s (%s): %s", c->name, c->hostname, sockstrerror(result));
 346                         terminate_connection(mesh, c, false);
 347                         return;
 348                 }
 349         }
 350
 351         if(flags & IO_WRITE)
 352                 handle_meta_write(mesh, c);
 353         else
 354                 handle_meta_connection_data(mesh, c);
 355 }
 356
 357 bool do_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 358         char *address, *port, *space;
 359         struct addrinfo *proxyai = NULL;
 360         int result;
 361
 362 begin:
 363         if(!outgoing->ai) {
 364                 if(!outgoing->cfg) {
 365                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not set up a meta connection to %s", outgoing->name);
 366                         retry_outgoing(mesh, outgoing);
 367                         return false;
 368                 }
 369
 370                 get_config_string(outgoing->cfg, &address);
 371
 372                 space = strchr(address, ' ');
 373                 if(space) {
 374                         port = xstrdup(space + 1);
 375                         *space = 0;
 376                 } else {
 377                         // TODO: Only allow Address statements?
 378                         if(!get_config_string(lookup_config(outgoing->config_tree, "Port"), &port))
 379                                 port = xstrdup("655");
 380                 }
 381
 382                 outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 383                 free(address);
 384                 free(port);
 385
 386                 outgoing->aip = outgoing->ai;
 387                 outgoing->cfg = lookup_config_next(outgoing->config_tree, outgoing->cfg);
 388         }
 389
 390         if(!outgoing->aip) {
 391                 if(outgoing->ai)
 392                         freeaddrinfo(outgoing->ai);
 393                 outgoing->ai = NULL;
 394                 goto begin;
 395         }
 396
 397         connection_t *c = new_connection();
 398         c->outgoing = outgoing;
 399
 400         memcpy(&c->address, outgoing->aip->ai_addr, outgoing->aip->ai_addrlen);
 401         outgoing->aip = outgoing->aip->ai_next;
 402
 403         c->hostname = sockaddr2hostname(&c->address);
 404
 405         logger(DEBUG_CONNECTIONS, LOG_INFO, "Trying to connect to %s (%s)", outgoing->name, c->hostname);
 406
 407         if(!mesh->proxytype) {
 408                 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 409                 configure_tcp(c);
 410         } else if(mesh->proxytype == PROXY_EXEC) {
 411                 do_outgoing_pipe(mesh, c, mesh->proxyhost);
 412         } else {
 413                 proxyai = str2addrinfo(mesh->proxyhost, mesh->proxyport, SOCK_STREAM);
 414                 if(!proxyai) {
 415                         free_connection(c);
 416                         goto begin;
 417                 }
 418                 logger(DEBUG_CONNECTIONS, LOG_INFO, "Using proxy at %s port %s", mesh->proxyhost, mesh->proxyport);
 419                 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
 420                 configure_tcp(c);
 421         }
 422
 423         if(c->socket == -1) {
 424                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
 425                 free_connection(c);
 426                 goto begin;
 427         }
 428
 429 #ifdef FD_CLOEXEC
 430         fcntl(c->socket, F_SETFD, FD_CLOEXEC);
 431 #endif
 432
 433         if(mesh->proxytype != PROXY_EXEC) {
 434 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 435                 int option = 1;
 436                 if(c->address.sa.sa_family == AF_INET6)
 437                         setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 438 #endif
 439
 440                 bind_to_address(mesh, c);
 441         }
 442
 443         /* Connect */
 444
 445         if(!mesh->proxytype) {
 446                 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 447         } else if(mesh->proxytype == PROXY_EXEC) {
 448                 result = 0;
 449         } else {
 450                 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
 451                 freeaddrinfo(proxyai);
 452         }
 453
 454         if(result == -1 && !sockinprogress(sockerrno)) {
 455                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not connect to %s (%s): %s", outgoing->name, c->hostname, sockstrerror(sockerrno));
 456                 free_connection(c);
 457
 458                 goto begin;
 459         }
 460
 461         /* Now that there is a working socket, fill in the rest and register this connection. */
 462
 463         c->status.connecting = true;
 464         c->name = xstrdup(outgoing->name);
 465         c->outcompression = mesh->self->connection->outcompression;
 466         c->last_ping_time = mesh->loop.now.tv_sec;
 467
 468         connection_add(mesh, c);
 469
 470         io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ|IO_WRITE);
 471
 472         return true;
 473 }
 474
 475 // Find edges pointing to this node, and use them to build a list of unique, known addresses.
 476 static struct addrinfo *get_known_addresses(node_t *n) {
 477         struct addrinfo *ai = NULL;
 478
 479         for splay_each(edge_t, e, n->edge_tree) {
 480                 if(!e->reverse)
 481                         continue;
 482
 483                 bool found = false;
 484                 for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
 485                         if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
 486                                 found = true;
 487                                 break;
 488                         }
 489                 }
 490                 if(found)
 491                         continue;
 492
 493                 struct addrinfo *nai = xzalloc(sizeof *nai);
 494                 if(ai)
 495                         ai->ai_next = nai;
 496                 ai = nai;
 497                 ai->ai_family = e->reverse->address.sa.sa_family;
 498                 ai->ai_socktype = SOCK_STREAM;
 499                 ai->ai_protocol = IPPROTO_TCP;
 500                 ai->ai_addrlen = SALEN(e->reverse->address.sa);
 501                 ai->ai_addr = xmalloc(ai->ai_addrlen);
 502                 memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
 503         }
 504
 505         return ai;
 506 }
 507
 508 void setup_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 509         timeout_del(&mesh->loop, &outgoing->ev);
 510
 511         node_t *n = lookup_node(mesh, outgoing->name);
 512
 513         if(n && n->connection) {
 514                 logger(DEBUG_CONNECTIONS, LOG_INFO, "Already connected to %s", outgoing->name);
 515
 516                 n->connection->outgoing = outgoing;
 517                 return;
 518         }
 519
 520         init_configuration(&outgoing->config_tree);
 521         read_host_config(mesh, outgoing->config_tree, outgoing->name);
 522         outgoing->cfg = lookup_config(outgoing->config_tree, "Address");
 523
 524         if(!outgoing->cfg) {
 525                 if(n)
 526                         outgoing->aip = outgoing->ai = get_known_addresses(n);
 527                 if(!outgoing->ai) {
 528                         logger(DEBUG_ALWAYS, LOG_ERR, "No address known for %s", outgoing->name);
 529                         return;
 530                 }
 531         }
 532
 533         do_outgoing_connection(mesh, outgoing);
 534 }
 535
 536 /*
 537   accept a new tcp connect and create a
 538   new connection
 539 */
 540 void handle_new_meta_connection(event_loop_t *loop, void *data, int flags) {
 541         meshlink_handle_t *mesh = loop->data;
 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(mesh->loop.now.tv_sec - samehost_burst_time > samehost_burst)
 572                         samehost_burst = 0;
 573                 else
 574                         samehost_burst -= mesh->loop.now.tv_sec - samehost_burst_time;
 575
 576                 samehost_burst_time = mesh->loop.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(mesh->loop.now.tv_sec - connection_burst_time > connection_burst)
 593                 connection_burst = 0;
 594         else
 595                 connection_burst -= mesh->loop.now.tv_sec - connection_burst_time;
 596
 597         connection_burst_time = mesh->loop.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 = mesh->loop.now.tv_sec;
 616
 617         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection from %s", c->hostname);
 618
 619         io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ);
 620
 621         configure_tcp(c);
 622
 623         connection_add(mesh, c);
 624
 625         c->allow_request = ID;
 626         send_id(mesh, c);
 627 }
 628
 629 static void free_outgoing(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 630         timeout_del(&mesh->loop, &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(meshlink_handle_t *mesh) {
 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(mesh, 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(mesh, 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 }