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 do_outgoing_pipe(meshlink_handle_t *mesh, connection_t *c, char *command) {
 290 #ifndef HAVE_MINGW
 291         int fd[2];
 292
 293         if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd)) {
 294                 logger(mesh, MESHLINK_ERROR, "Could not create socketpair: %s", strerror(errno));
 295                 return;
 296         }
 297
 298         if(fork()) {
 299                 c->socket = fd[0];
 300                 close(fd[1]);
 301                 logger(mesh, MESHLINK_DEBUG, "Using proxy %s", command);
 302                 return;
 303         }
 304
 305         close(0);
 306         close(1);
 307         close(fd[0]);
 308         dup2(fd[1], 0);
 309         dup2(fd[1], 1);
 310         close(fd[1]);
 311
 312         // Other filedescriptors should be closed automatically by CLOEXEC
 313
 314         char *host = NULL;
 315         char *port = NULL;
 316
 317         sockaddr2str(&c->address, &host, &port);
 318         setenv("REMOTEADDRESS", host, true);
 319         setenv("REMOTEPORT", port, true);
 320         setenv("NODE", c->name, true);
 321         setenv("NAME", mesh->self->name, true);
 322
 323         int result = system(command);
 324
 325         if(result < 0) {
 326                 logger(mesh, MESHLINK_ERROR, "Could not execute %s: %s", command, strerror(errno));
 327         } else if(result) {
 328                 logger(mesh, MESHLINK_ERROR, "%s exited with non-zero status %d", command, result);
 329         }
 330
 331         exit(result);
 332 #else
 333         logger(mesh, MESHLINK_ERROR, "Proxy type exec not supported on this platform!");
 334         return;
 335 #endif
 336 }
 337
 338 static void handle_meta_write(meshlink_handle_t *mesh, connection_t *c) {
 339         if(c->outbuf.len <= c->outbuf.offset) {
 340                 return;
 341         }
 342
 343         ssize_t outlen = send(c->socket, c->outbuf.data + c->outbuf.offset, c->outbuf.len - c->outbuf.offset, MSG_NOSIGNAL);
 344
 345         if(outlen <= 0) {
 346                 if(!errno || errno == EPIPE) {
 347                         logger(mesh, MESHLINK_INFO, "Connection closed by %s", c->name);
 348                 } else if(sockwouldblock(sockerrno)) {
 349                         logger(mesh, MESHLINK_DEBUG, "Sending %lu bytes to %s would block", (unsigned long)(c->outbuf.len - c->outbuf.offset), c->name);
 350                         return;
 351                 } else {
 352                         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));
 353                 }
 354
 355                 terminate_connection(mesh, c, c->status.active);
 356                 return;
 357         }
 358
 359         buffer_read(&c->outbuf, outlen);
 360
 361         if(!c->outbuf.len) {
 362                 io_set(&mesh->loop, &c->io, IO_READ);
 363         }
 364 }
 365
 366 static void handle_meta_io(event_loop_t *loop, void *data, int flags) {
 367         meshlink_handle_t *mesh = loop->data;
 368         connection_t *c = data;
 369
 370         if(c->status.connecting) {
 371                 c->status.connecting = false;
 372
 373                 int result;
 374                 socklen_t len = sizeof(result);
 375                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&result, &len);
 376
 377                 if(!result) {
 378                         finish_connecting(mesh, c);
 379                 } else {
 380                         logger(mesh, MESHLINK_DEBUG, "Error while connecting to %s: %s", c->name, sockstrerror(result));
 381                         terminate_connection(mesh, c, false);
 382                         return;
 383                 }
 384         }
 385
 386         if(flags & IO_WRITE) {
 387                 handle_meta_write(mesh, c);
 388         } else {
 389                 handle_meta_connection_data(mesh, c);
 390         }
 391 }
 392
 393 // Find edges pointing to this node, and use them to build a list of unique, known addresses.
 394 static struct addrinfo *get_known_addresses(node_t *n) {
 395         struct addrinfo *ai = NULL;
 396
 397         for splay_each(edge_t, e, n->edge_tree) {
 398                 if(!e->reverse) {
 399                         continue;
 400                 }
 401
 402                 bool found = false;
 403
 404                 for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
 405                         if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
 406                                 found = true;
 407                                 break;
 408                         }
 409                 }
 410
 411                 if(found) {
 412                         continue;
 413                 }
 414
 415                 // Create a new struct addrinfo, and put it at the head of the list.
 416                 struct addrinfo *nai = xzalloc(sizeof(*nai) + SALEN(e->reverse->address.sa));
 417                 nai->ai_next = ai;
 418                 ai = nai;
 419
 420                 ai->ai_family = e->reverse->address.sa.sa_family;
 421                 ai->ai_socktype = SOCK_STREAM;
 422                 ai->ai_protocol = IPPROTO_TCP;
 423                 ai->ai_addrlen = SALEN(e->reverse->address.sa);
 424                 ai->ai_addr = (struct sockaddr *)(nai + 1);
 425                 memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
 426         }
 427
 428         return ai;
 429 }
 430
 431 // Free struct addrinfo list from get_known_addresses().
 432 static void free_known_addresses(struct addrinfo *ai) {
 433         for(struct addrinfo *aip = ai, *next; aip; aip = next) {
 434                 next = aip->ai_next;
 435                 free(aip);
 436         }
 437 }
 438
 439 bool do_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 440         char *address, *port, *space;
 441         struct addrinfo *proxyai = NULL;
 442         int result;
 443
 444 begin:
 445
 446         if(!outgoing->ai && !outgoing->nai) {
 447                 if(!outgoing->cfg) {
 448                         logger(mesh, MESHLINK_ERROR, "Could not set up a meta connection to %s", outgoing->name);
 449                         retry_outgoing(mesh, outgoing);
 450                         return false;
 451                 }
 452
 453                 get_config_string(outgoing->cfg, &address);
 454
 455                 space = strchr(address, ' ');
 456
 457                 if(space) {
 458                         port = xstrdup(space + 1);
 459                         *space = 0;
 460                 } else {
 461                         // TODO: Only allow Address statements?
 462                         if(!get_config_string(lookup_config(outgoing->config_tree, "Port"), &port)) {
 463                                 logger(mesh, MESHLINK_ERROR, "No Port known for %s", outgoing->name);
 464                                 retry_outgoing(mesh, outgoing);
 465                                 return false;
 466                         }
 467                 }
 468
 469                 outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 470                 free(address);
 471                 free(port);
 472
 473                 outgoing->aip = outgoing->ai;
 474                 outgoing->cfg = lookup_config_next(outgoing->config_tree, outgoing->cfg);
 475         }
 476
 477         if(!outgoing->aip) {
 478                 if(outgoing->ai) {
 479                         freeaddrinfo(outgoing->ai);
 480                 }
 481
 482                 outgoing->ai = NULL;
 483
 484                 if(outgoing->nai) {
 485                         free_known_addresses(outgoing->nai);
 486                 }
 487
 488                 outgoing->nai = NULL;
 489
 490                 goto begin;
 491         }
 492
 493         connection_t *c = new_connection();
 494         c->outgoing = outgoing;
 495
 496         memcpy(&c->address, outgoing->aip->ai_addr, outgoing->aip->ai_addrlen);
 497         outgoing->aip = outgoing->aip->ai_next;
 498
 499         char *hostname = sockaddr2hostname(&c->address);
 500
 501         logger(mesh, MESHLINK_INFO, "Trying to connect to %s at %s", outgoing->name, hostname);
 502
 503         if(!mesh->proxytype) {
 504                 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 505                 configure_tcp(c);
 506         } else if(mesh->proxytype == PROXY_EXEC) {
 507                 do_outgoing_pipe(mesh, c, mesh->proxyhost);
 508         } else {
 509                 proxyai = str2addrinfo(mesh->proxyhost, mesh->proxyport, SOCK_STREAM);
 510
 511                 if(!proxyai) {
 512                         free_connection(c);
 513                         free(hostname);
 514                         goto begin;
 515                 }
 516
 517                 logger(mesh, MESHLINK_INFO, "Using proxy at %s port %s", mesh->proxyhost, mesh->proxyport);
 518                 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
 519                 configure_tcp(c);
 520         }
 521
 522         if(c->socket == -1) {
 523                 logger(mesh, MESHLINK_ERROR, "Creating socket for %s at %s failed: %s", c->name, c->hostname, sockstrerror(sockerrno));
 524                 free_connection(c);
 525                 free(hostname);
 526                 goto begin;
 527         }
 528
 529         free(hostname);
 530
 531 #ifdef FD_CLOEXEC
 532         fcntl(c->socket, F_SETFD, FD_CLOEXEC);
 533 #endif
 534
 535         if(mesh->proxytype != PROXY_EXEC) {
 536 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 537                 int option = 1;
 538
 539                 if(c->address.sa.sa_family == AF_INET6) {
 540                         setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
 541                 }
 542
 543 #endif
 544
 545                 bind_to_address(mesh, c);
 546         }
 547
 548         /* Connect */
 549
 550         if(!mesh->proxytype) {
 551                 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 552         } else if(mesh->proxytype == PROXY_EXEC) {
 553                 result = 0;
 554         } else {
 555                 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
 556                 freeaddrinfo(proxyai);
 557         }
 558
 559         if(result == -1 && !sockinprogress(sockerrno)) {
 560                 logger(mesh, MESHLINK_ERROR, "Could not connect to %s: %s", outgoing->name, sockstrerror(sockerrno));
 561                 free_connection(c);
 562
 563                 goto begin;
 564         }
 565
 566         /* Now that there is a working socket, fill in the rest and register this connection. */
 567
 568         c->status.connecting = true;
 569         c->name = xstrdup(outgoing->name);
 570         c->outcompression = mesh->self->connection->outcompression;
 571         c->last_ping_time = mesh->loop.now.tv_sec;
 572
 573         connection_add(mesh, c);
 574
 575         io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ | IO_WRITE);
 576
 577         return true;
 578 }
 579
 580 void setup_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 581         bool blacklisted = false;
 582         timeout_del(&mesh->loop, &outgoing->ev);
 583
 584         node_t *n = lookup_node(mesh, outgoing->name);
 585
 586         if(n && n->connection) {
 587                 logger(mesh, MESHLINK_INFO, "Already connected to %s", outgoing->name);
 588
 589                 n->connection->outgoing = outgoing;
 590                 return;
 591         }
 592
 593         exit_configuration(&outgoing->config_tree); // discard old configuration if present
 594         init_configuration(&outgoing->config_tree);
 595         read_host_config(mesh, outgoing->config_tree, outgoing->name);
 596         outgoing->cfg = lookup_config(outgoing->config_tree, "Address");
 597
 598         get_config_bool(lookup_config(outgoing->config_tree, "blacklisted"), &blacklisted);
 599
 600         if(blacklisted) {
 601                 return;
 602         }
 603
 604         if(!outgoing->cfg) {
 605                 if(n) {
 606                         outgoing->aip = outgoing->nai = get_known_addresses(n);
 607                 }
 608
 609                 if(!outgoing->nai) {
 610                         logger(mesh, MESHLINK_ERROR, "No address known for %s", outgoing->name);
 611                         return;
 612                 }
 613         }
 614
 615         do_outgoing_connection(mesh, outgoing);
 616 }
 617
 618 /*
 619   accept a new tcp connect and create a
 620   new connection
 621 */
 622 void handle_new_meta_connection(event_loop_t *loop, void *data, int flags) {
 623         (void)flags;
 624         meshlink_handle_t *mesh = loop->data;
 625         listen_socket_t *l = data;
 626         connection_t *c;
 627         sockaddr_t sa;
 628         int fd;
 629         socklen_t len = sizeof(sa);
 630
 631         fd = accept(l->tcp.fd, &sa.sa, &len);
 632
 633         if(fd < 0) {
 634                 if(errno == EINVAL) { // TODO: check if Windows agrees
 635                         event_loop_stop(loop);
 636                         return;
 637                 }
 638
 639                 logger(mesh, MESHLINK_ERROR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 640                 return;
 641         }
 642
 643         sockaddrunmap(&sa);
 644
 645         // Check if we get many connections from the same host
 646
 647         static sockaddr_t prev_sa;
 648         static int tarpit = -1;
 649
 650         if(tarpit >= 0) {
 651                 closesocket(tarpit);
 652                 tarpit = -1;
 653         }
 654
 655         if(!sockaddrcmp_noport(&sa, &prev_sa)) {
 656                 static int samehost_burst;
 657                 static int samehost_burst_time;
 658
 659                 if(mesh->loop.now.tv_sec - samehost_burst_time > samehost_burst) {
 660                         samehost_burst = 0;
 661                 } else {
 662                         samehost_burst -= mesh->loop.now.tv_sec - samehost_burst_time;
 663                 }
 664
 665                 samehost_burst_time = mesh->loop.now.tv_sec;
 666                 samehost_burst++;
 667
 668                 if(samehost_burst > max_connection_burst) {
 669                         tarpit = fd;
 670                         return;
 671                 }
 672         }
 673
 674         memcpy(&prev_sa, &sa, sizeof(sa));
 675
 676         // Check if we get many connections from different hosts
 677
 678         static int connection_burst;
 679         static int connection_burst_time;
 680
 681         if(mesh->loop.now.tv_sec - connection_burst_time > connection_burst) {
 682                 connection_burst = 0;
 683         } else {
 684                 connection_burst -= mesh->loop.now.tv_sec - connection_burst_time;
 685         }
 686
 687         connection_burst_time = mesh->loop.now.tv_sec;
 688         connection_burst++;
 689
 690         if(connection_burst >= max_connection_burst) {
 691                 connection_burst = max_connection_burst;
 692                 tarpit = fd;
 693                 return;
 694         }
 695
 696         // Accept the new connection
 697
 698         c = new_connection();
 699         c->name = xstrdup("<unknown>");
 700         c->outcompression = mesh->self->connection->outcompression;
 701
 702         c->address = sa;
 703         c->socket = fd;
 704         c->last_ping_time = mesh->loop.now.tv_sec;
 705
 706         char *hostname = sockaddr2hostname(&sa);
 707         logger(mesh, MESHLINK_INFO, "Connection from %s", c->hostname);
 708         free(hostname);
 709
 710         io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ);
 711
 712         configure_tcp(c);
 713
 714         connection_add(mesh, c);
 715
 716         c->allow_request = ID;
 717         send_id(mesh, c);
 718 }
 719
 720 static void free_outgoing(outgoing_t *outgoing) {
 721         meshlink_handle_t *mesh = outgoing->mesh;
 722
 723         timeout_del(&mesh->loop, &outgoing->ev);
 724
 725         if(outgoing->ai) {
 726                 freeaddrinfo(outgoing->ai);
 727         }
 728
 729         if(outgoing->nai) {
 730                 free_known_addresses(outgoing->nai);
 731         }
 732
 733         if(outgoing->config_tree) {
 734                 exit_configuration(&outgoing->config_tree);
 735         }
 736
 737         if(outgoing->name) {
 738                 free(outgoing->name);
 739         }
 740
 741         free(outgoing);
 742 }
 743
 744 void try_outgoing_connections(meshlink_handle_t *mesh) {
 745         /* If there is no outgoing list yet, create one. Otherwise, mark all outgoings as deleted. */
 746
 747         if(!mesh->outgoings) {
 748                 mesh->outgoings = list_alloc((list_action_t)free_outgoing);
 749         } else {
 750                 for list_each(outgoing_t, outgoing, mesh->outgoings) {
 751                         outgoing->timeout = -1;
 752                 }
 753         }
 754
 755         /* Make sure there is one outgoing_t in the list for each ConnectTo. */
 756
 757         // TODO: Drop support for ConnectTo since AutoConnect is now always on?
 758         for(config_t *cfg = lookup_config(mesh->config, "ConnectTo"); cfg; cfg = lookup_config_next(mesh->config, cfg)) {
 759                 char *name;
 760                 get_config_string(cfg, &name);
 761
 762                 if(!check_id(name)) {
 763                         logger(mesh, MESHLINK_ERROR,
 764                                "Invalid name for outgoing connection in %s line %d",
 765                                cfg->file, cfg->line);
 766                         free(name);
 767                         continue;
 768                 }
 769
 770                 bool found = false;
 771
 772                 for list_each(outgoing_t, outgoing, mesh->outgoings) {
 773                         if(!strcmp(outgoing->name, name)) {
 774                                 found = true;
 775                                 outgoing->timeout = 0;
 776                                 break;
 777                         }
 778                 }
 779
 780                 if(!found) {
 781                         outgoing_t *outgoing = xzalloc(sizeof(*outgoing));
 782                         outgoing->mesh = mesh;
 783                         outgoing->name = name;
 784                         list_insert_tail(mesh->outgoings, outgoing);
 785                         setup_outgoing_connection(mesh, outgoing);
 786                 }
 787         }
 788
 789         /* Terminate any connections whose outgoing_t is to be deleted. */
 790
 791         for list_each(connection_t, c, mesh->connections) {
 792                 if(c->outgoing && c->outgoing->timeout == -1) {
 793                         c->outgoing = NULL;
 794                         logger(mesh, MESHLINK_INFO, "No more outgoing connection to %s", c->name);
 795                         terminate_connection(mesh, c, c->status.active);
 796                 }
 797         }
 798
 799         /* Delete outgoing_ts for which there is no ConnectTo. */
 800
 801         for list_each(outgoing_t, outgoing, mesh->outgoings)
 802                 if(outgoing->timeout == -1) {
 803                         list_delete_node(mesh->outgoings, node);
 804                 }
 805 }