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 #elif defined(WIN32)
  56         unsigned long arg = 1;
  57
  58         if(ioctlsocket(c->socket, FIONBIO, &arg) != 0)
  59                 logger(c->mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
  60 #endif
  61
  62 #if defined(SOL_TCP) && defined(TCP_NODELAY)
  63         int nodelay = 1;
  64         setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&nodelay, sizeof(nodelay));
  65 #endif
  66
  67 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
  68         int lowdelay = IPTOS_LOWDELAY;
  69         setsockopt(c->socket, SOL_IP, IP_TOS, (void *)&lowdelay, sizeof(lowdelay));
  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(mesh, MESHLINK_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
 106         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 107
 108         if(nfd < 0) {
 109                 logger(NULL, MESHLINK_ERROR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
 110                 return -1;
 111         }
 112
 113 #ifdef FD_CLOEXEC
 114         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 115 #endif
 116
 117         /* Optimize TCP settings */
 118
 119         option = 1;
 120         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
 121
 122 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 123         if(sa->sa.sa_family == AF_INET6)
 124                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
 125 #endif
 126
 127         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 128                 closesocket(nfd);
 129                 addrstr = sockaddr2hostname(sa);
 130                 logger(NULL, MESHLINK_ERROR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
 131                 free(addrstr);
 132                 return -1;
 133         }
 134
 135         if(listen(nfd, 3)) {
 136                 closesocket(nfd);
 137                 logger(NULL, MESHLINK_ERROR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
 138                 return -1;
 139         }
 140
 141         return nfd;
 142 }
 143
 144 int setup_vpn_in_socket(meshlink_handle_t *mesh, const sockaddr_t *sa) {
 145         int nfd;
 146         char *addrstr;
 147         int option;
 148
 149         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 150
 151         if(nfd < 0) {
 152                 logger(mesh, MESHLINK_ERROR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
 153                 return -1;
 154         }
 155
 156 #ifdef FD_CLOEXEC
 157         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 158 #endif
 159
 160 #ifdef O_NONBLOCK
 161         {
 162                 int flags = fcntl(nfd, F_GETFL);
 163
 164                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
 165                         closesocket(nfd);
 166                         logger(mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "fcntl",
 167                                strerror(errno));
 168                         return -1;
 169                 }
 170         }
 171 #elif defined(WIN32)
 172         {
 173                 unsigned long arg = 1;
 174                 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
 175                         closesocket(nfd);
 176                         logger(mesh, MESHLINK_ERROR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
 177                         return -1;
 178                 }
 179         }
 180 #endif
 181
 182         option = 1;
 183         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
 184         setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof(option));
 185
 186 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
 187         if(sa->sa.sa_family == AF_INET6)
 188                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
 189 #endif
 190
 191 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
 192 #define IP_DONTFRAGMENT IP_DONTFRAG
 193 #endif
 194
 195 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 196         if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
 197                 option = IP_PMTUDISC_DO;
 198                 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
 199         }
 200 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
 201         if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
 202                 option = 1;
 203                 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
 204         }
 205 #else
 206 #warning No way to disable IPv4 fragmentation
 207 #endif
 208
 209 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 210         if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
 211                 option = IPV6_PMTUDISC_DO;
 212                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
 213         }
 214 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
 215         if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
 216                 option = 1;
 217                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
 218         }
 219 #else
 220 #warning No way to disable IPv6 fragmentation
 221 #endif
 222
 223         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 224                 closesocket(nfd);
 225                 addrstr = sockaddr2hostname(sa);
 226                 logger(mesh, MESHLINK_ERROR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
 227                 free(addrstr);
 228                 return -1;
 229         }
 230
 231         return nfd;
 232 } /* int setup_vpn_in_socket */
 233
 234 static void retry_outgoing_handler(event_loop_t *loop, void *data) {
 235         meshlink_handle_t *mesh = loop->data;
 236         outgoing_t *outgoing = data;
 237         setup_outgoing_connection(mesh, outgoing);
 238 }
 239
 240 void retry_outgoing(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 241         outgoing->timeout += 5;
 242
 243         if(outgoing->timeout > mesh->maxtimeout)
 244                 outgoing->timeout = mesh->maxtimeout;
 245
 246         timeout_add(&mesh->loop, &outgoing->ev, retry_outgoing_handler, outgoing, &(struct timeval) {
 247                 outgoing->timeout, rand() % 100000
 248         });
 249
 250         logger(mesh, MESHLINK_INFO, "Trying to re-establish outgoing connection in %d seconds", outgoing->timeout);
 251 }
 252
 253 void finish_connecting(meshlink_handle_t *mesh, connection_t *c) {
 254         logger(mesh, MESHLINK_INFO, "Connected to %s", c->name);
 255
 256         c->last_ping_time = mesh->loop.now.tv_sec;
 257         c->status.connecting = false;
 258
 259         send_id(mesh, c);
 260 }
 261
 262 static void do_outgoing_pipe(meshlink_handle_t *mesh, connection_t *c, char *command) {
 263 #ifndef HAVE_MINGW
 264         int fd[2];
 265
 266         if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd)) {
 267                 logger(mesh, MESHLINK_ERROR, "Could not create socketpair: %s", strerror(errno));
 268                 return;
 269         }
 270
 271         if(fork()) {
 272                 c->socket = fd[0];
 273                 close(fd[1]);
 274                 logger(mesh, MESHLINK_DEBUG, "Using proxy %s", command);
 275                 return;
 276         }
 277
 278         close(0);
 279         close(1);
 280         close(fd[0]);
 281         dup2(fd[1], 0);
 282         dup2(fd[1], 1);
 283         close(fd[1]);
 284
 285         // Other filedescriptors should be closed automatically by CLOEXEC
 286
 287         char *host = NULL;
 288         char *port = NULL;
 289
 290         sockaddr2str(&c->address, &host, &port);
 291         setenv("REMOTEADDRESS", host, true);
 292         setenv("REMOTEPORT", port, true);
 293         setenv("NODE", c->name, true);
 294         setenv("NAME", mesh->self->name, true);
 295
 296         int result = system(command);
 297         if(result < 0)
 298                 logger(mesh, MESHLINK_ERROR, "Could not execute %s: %s", command, strerror(errno));
 299         else if(result)
 300                 logger(mesh, MESHLINK_ERROR, "%s exited with non-zero status %d", command, result);
 301         exit(result);
 302 #else
 303         logger(mesh, MESHLINK_ERROR, "Proxy type exec not supported on this platform!");
 304         return;
 305 #endif
 306 }
 307
 308 static void handle_meta_write(meshlink_handle_t *mesh, connection_t *c) {
 309         if(c->outbuf.len <= c->outbuf.offset)
 310                 return;
 311
 312         ssize_t outlen = send(c->socket, c->outbuf.data + c->outbuf.offset, c->outbuf.len - c->outbuf.offset, MSG_NOSIGNAL);
 313         if(outlen <= 0) {
 314                 if(!errno || errno == EPIPE) {
 315                         logger(mesh, MESHLINK_INFO, "Connection closed by %s", c->name);
 316                 } else if(sockwouldblock(sockerrno)) {
 317                         logger(mesh, MESHLINK_DEBUG, "Sending %lu bytes to %s would block", (unsigned long)(c->outbuf.len - c->outbuf.offset), c->name);
 318                         return;
 319                 } else {
 320                         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));
 321                 }
 322
 323                 terminate_connection(mesh, c, c->status.active);
 324                 return;
 325         }
 326
 327         buffer_read(&c->outbuf, outlen);
 328         if(!c->outbuf.len)
 329                 io_set(&mesh->loop, &c->io, IO_READ);
 330 }
 331
 332 static void handle_meta_io(event_loop_t *loop, void *data, int flags) {
 333         meshlink_handle_t *mesh = loop->data;
 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(mesh, c);
 345                 else {
 346                         logger(mesh, MESHLINK_DEBUG, "Error while connecting to %s: %s", c->name, sockstrerror(result));
 347                         terminate_connection(mesh, c, false);
 348                         return;
 349                 }
 350         }
 351
 352         if(flags & IO_WRITE)
 353                 handle_meta_write(mesh, c);
 354         else
 355                 handle_meta_connection_data(mesh, c);
 356 }
 357
 358 // Find edges pointing to this node, and use them to build a list of unique, known addresses.
 359 static struct addrinfo *get_known_addresses(node_t *n) {
 360         struct addrinfo *ai = NULL;
 361
 362         for splay_each(edge_t, e, n->edge_tree) {
 363                 if(!e->reverse)
 364                         continue;
 365
 366                 bool found = false;
 367                 for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
 368                         if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
 369                                 found = true;
 370                                 break;
 371                         }
 372                 }
 373                 if(found)
 374                         continue;
 375
 376                 // Create a new struct addrinfo, and put it at the head of the list.
 377                 struct addrinfo *nai = xzalloc(sizeof(*nai) + SALEN(e->reverse->address.sa));
 378                 nai->ai_next = ai;
 379                 ai = nai;
 380
 381                 ai->ai_family = e->reverse->address.sa.sa_family;
 382                 ai->ai_socktype = SOCK_STREAM;
 383                 ai->ai_protocol = IPPROTO_TCP;
 384                 ai->ai_addrlen = SALEN(e->reverse->address.sa);
 385                 ai->ai_addr = (struct sockaddr *)(nai + 1);
 386                 memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
 387         }
 388
 389         return ai;
 390 }
 391
 392 // Free struct addrinfo list from get_known_addresses().
 393 static void free_known_addresses(struct addrinfo *ai) {
 394         for(struct addrinfo *aip = ai, *next; aip; aip = next) {
 395                 next = aip->ai_next;
 396                 free(aip);
 397         }
 398 }
 399
 400 bool do_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 401         char *address, *port, *space;
 402         struct addrinfo *proxyai = NULL;
 403         int result;
 404
 405 begin:
 406         if(!outgoing->ai && !outgoing->nai) {
 407                 if(!outgoing->cfg) {
 408                         logger(mesh, MESHLINK_ERROR, "Could not set up a meta connection to %s", outgoing->name);
 409                         retry_outgoing(mesh, outgoing);
 410                         return false;
 411                 }
 412
 413                 get_config_string(outgoing->cfg, &address);
 414
 415                 space = strchr(address, ' ');
 416                 if(space) {
 417                         port = xstrdup(space + 1);
 418                         *space = 0;
 419                 } else {
 420                         // TODO: Only allow Address statements?
 421                         if(!get_config_string(lookup_config(outgoing->config_tree, "Port"), &port)) {
 422                                 logger(mesh, MESHLINK_ERROR, "No Port known for %s", outgoing->name);
 423                                 retry_outgoing(mesh, outgoing);
 424                                 return false;
 425                         }
 426                 }
 427
 428                 outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 429                 free(address);
 430                 free(port);
 431
 432                 outgoing->aip = outgoing->ai;
 433                 outgoing->cfg = lookup_config_next(outgoing->config_tree, outgoing->cfg);
 434         }
 435
 436         if(!outgoing->aip) {
 437                 if(outgoing->ai)
 438                         freeaddrinfo(outgoing->ai);
 439                 outgoing->ai = NULL;
 440
 441                 if(outgoing->nai)
 442                         free_known_addresses(outgoing->nai);
 443                 outgoing->nai = NULL;
 444
 445                 goto begin;
 446         }
 447
 448         connection_t *c = new_connection();
 449         c->outgoing = outgoing;
 450
 451         memcpy(&c->address, outgoing->aip->ai_addr, outgoing->aip->ai_addrlen);
 452         outgoing->aip = outgoing->aip->ai_next;
 453
 454         char *hostname = sockaddr2hostname(&c->address);
 455
 456         logger(mesh, MESHLINK_INFO, "Trying to connect to %s at %s", outgoing->name, hostname);
 457
 458         if(!mesh->proxytype) {
 459                 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 460                 configure_tcp(c);
 461         } else if(mesh->proxytype == PROXY_EXEC)
 462                 do_outgoing_pipe(mesh, c, mesh->proxyhost);
 463         else {
 464                 proxyai = str2addrinfo(mesh->proxyhost, mesh->proxyport, SOCK_STREAM);
 465                 if(!proxyai) {
 466                         free_connection(c);
 467                         free(hostname);
 468                         goto begin;
 469                 }
 470                 logger(mesh, MESHLINK_INFO, "Using proxy at %s port %s", mesh->proxyhost, mesh->proxyport);
 471                 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
 472                 configure_tcp(c);
 473         }
 474
 475         if(c->socket == -1) {
 476                 logger(mesh, MESHLINK_ERROR, "Creating socket for %s at %s failed: %s", c->name, c->hostname, sockstrerror(sockerrno));
 477                 free_connection(c);
 478                 free(hostname);
 479                 goto begin;
 480         }
 481
 482         free(hostname);
 483
 484 #ifdef FD_CLOEXEC
 485         fcntl(c->socket, F_SETFD, FD_CLOEXEC);
 486 #endif
 487
 488         if(mesh->proxytype != PROXY_EXEC) {
 489 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 490                 int option = 1;
 491                 if(c->address.sa.sa_family == AF_INET6)
 492                         setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
 493 #endif
 494
 495                 bind_to_address(mesh, c);
 496         }
 497
 498         /* Connect */
 499
 500         if(!mesh->proxytype)
 501                 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 502         else if(mesh->proxytype == PROXY_EXEC)
 503                 result = 0;
 504         else {
 505                 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
 506                 freeaddrinfo(proxyai);
 507         }
 508
 509         if(result == -1 && !sockinprogress(sockerrno)) {
 510                 logger(mesh, MESHLINK_ERROR, "Could not connect to %s: %s", outgoing->name, sockstrerror(sockerrno));
 511                 free_connection(c);
 512
 513                 goto begin;
 514         }
 515
 516         /* Now that there is a working socket, fill in the rest and register this connection. */
 517
 518         c->status.connecting = true;
 519         c->name = xstrdup(outgoing->name);
 520         c->outcompression = mesh->self->connection->outcompression;
 521         c->last_ping_time = mesh->loop.now.tv_sec;
 522
 523         connection_add(mesh, c);
 524
 525         io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ | IO_WRITE);
 526
 527         return true;
 528 }
 529
 530 void setup_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 531         bool blacklisted = false;
 532         timeout_del(&mesh->loop, &outgoing->ev);
 533
 534         node_t *n = lookup_node(mesh, outgoing->name);
 535
 536         if(n && n->connection) {
 537                 logger(mesh, MESHLINK_INFO, "Already connected to %s", outgoing->name);
 538
 539                 n->connection->outgoing = outgoing;
 540                 return;
 541         }
 542
 543         exit_configuration(&outgoing->config_tree); // discard old configuration if present
 544         init_configuration(&outgoing->config_tree);
 545         read_host_config(mesh, outgoing->config_tree, outgoing->name);
 546         outgoing->cfg = lookup_config(outgoing->config_tree, "Address");
 547
 548         get_config_bool(lookup_config(outgoing->config_tree, "blacklisted"), &blacklisted);
 549         if(blacklisted) return;
 550
 551         if(!outgoing->cfg) {
 552                 if(n)
 553                         outgoing->aip = outgoing->nai = get_known_addresses(n);
 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                 samehost_burst_time = mesh->loop.now.tv_sec;
 610                 samehost_burst++;
 611
 612                 if(samehost_burst > max_connection_burst) {
 613                         tarpit = fd;
 614                         return;
 615                 }
 616         }
 617
 618         memcpy(&prev_sa, &sa, sizeof(sa));
 619
 620         // Check if we get many connections from different hosts
 621
 622         static int connection_burst;
 623         static int connection_burst_time;
 624
 625         if(mesh->loop.now.tv_sec - connection_burst_time > connection_burst)
 626                 connection_burst = 0;
 627         else
 628                 connection_burst -= mesh->loop.now.tv_sec - connection_burst_time;
 629
 630         connection_burst_time = mesh->loop.now.tv_sec;
 631         connection_burst++;
 632
 633         if(connection_burst >= max_connection_burst) {
 634                 connection_burst = max_connection_burst;
 635                 tarpit = fd;
 636                 return;
 637         }
 638
 639         // Accept the new connection
 640
 641         c = new_connection();
 642         c->name = xstrdup("<unknown>");
 643         c->outcompression = mesh->self->connection->outcompression;
 644
 645         c->address = sa;
 646         c->socket = fd;
 647         c->last_ping_time = mesh->loop.now.tv_sec;
 648
 649         char *hostname = sockaddr2hostname(&sa);
 650         logger(mesh, MESHLINK_INFO, "Connection from %s", c->hostname);
 651         free(hostname);
 652
 653         io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ);
 654
 655         configure_tcp(c);
 656
 657         connection_add(mesh, c);
 658
 659         c->allow_request = ID;
 660         send_id(mesh, c);
 661 }
 662
 663 static void free_outgoing(outgoing_t *outgoing) {
 664         meshlink_handle_t *mesh = outgoing->mesh;
 665
 666         timeout_del(&mesh->loop, &outgoing->ev);
 667
 668         if(outgoing->ai)
 669                 freeaddrinfo(outgoing->ai);
 670
 671         if(outgoing->nai)
 672                 free_known_addresses(outgoing->nai);
 673
 674         if(outgoing->config_tree)
 675                 exit_configuration(&outgoing->config_tree);
 676
 677         if(outgoing->name)
 678                 free(outgoing->name);
 679
 680         free(outgoing);
 681 }
 682
 683 void try_outgoing_connections(meshlink_handle_t *mesh) {
 684         /* If there is no outgoing list yet, create one. Otherwise, mark all outgoings as deleted. */
 685
 686         if(!mesh->outgoings)
 687                 mesh->outgoings = list_alloc((list_action_t)free_outgoing);
 688         else {
 689                 for list_each(outgoing_t, outgoing, mesh->outgoings)
 690                         outgoing->timeout = -1;
 691         }
 692
 693         /* Make sure there is one outgoing_t in the list for each ConnectTo. */
 694
 695         // TODO: Drop support for ConnectTo since AutoConnect is now always on?
 696         for(config_t *cfg = lookup_config(mesh->config, "ConnectTo"); cfg; cfg = lookup_config_next(mesh->config, cfg)) {
 697                 char *name;
 698                 get_config_string(cfg, &name);
 699
 700                 if(!check_id(name)) {
 701                         logger(mesh, MESHLINK_ERROR,
 702                                "Invalid name for outgoing connection in %s line %d",
 703                                cfg->file, cfg->line);
 704                         free(name);
 705                         continue;
 706                 }
 707
 708                 bool found = false;
 709
 710                 for list_each(outgoing_t, outgoing, mesh->outgoings) {
 711                         if(!strcmp(outgoing->name, name)) {
 712                                 found = true;
 713                                 outgoing->timeout = 0;
 714                                 break;
 715                         }
 716                 }
 717
 718                 if(!found) {
 719                         outgoing_t *outgoing = xzalloc(sizeof(*outgoing));
 720                         outgoing->mesh = mesh;
 721                         outgoing->name = name;
 722                         list_insert_tail(mesh->outgoings, outgoing);
 723                         setup_outgoing_connection(mesh, outgoing);
 724                 }
 725         }
 726
 727         /* Terminate any connections whose outgoing_t is to be deleted. */
 728
 729         for list_each(connection_t, c, mesh->connections) {
 730                 if(c->outgoing && c->outgoing->timeout == -1) {
 731                         c->outgoing = NULL;
 732                         logger(mesh, MESHLINK_INFO, "No more outgoing connection to %s", c->name);
 733                         terminate_connection(mesh, c, c->status.active);
 734                 }
 735         }
 736
 737         /* Delete outgoing_ts for which there is no ConnectTo. */
 738
 739         for list_each(outgoing_t, outgoing, mesh->outgoings)
 740                 if(outgoing->timeout == -1)
 741                         list_delete_node(mesh->outgoings, node);
 742 }