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(IP_TOS) && defined(IPTOS_LOWDELAY)
  72         int lowdelay = IPTOS_LOWDELAY;
  73         setsockopt(c->socket, IPPROTO_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(IPV6_V6ONLY)
 134
 135         if(sa->sa.sa_family == AF_INET6) {
 136                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
 137         }
 138
 139 #else
 140 #warning IPV6_V6ONLY not defined
 141 #endif
 142
 143         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 144                 closesocket(nfd);
 145                 addrstr = sockaddr2hostname(sa);
 146                 logger(NULL, MESHLINK_ERROR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
 147                 free(addrstr);
 148                 return -1;
 149         }
 150
 151         if(listen(nfd, 3)) {
 152                 closesocket(nfd);
 153                 logger(NULL, MESHLINK_ERROR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
 154                 return -1;
 155         }
 156
 157         return nfd;
 158 }
 159
 160 int setup_vpn_in_socket(meshlink_handle_t *mesh, const sockaddr_t *sa) {
 161         int nfd;
 162         char *addrstr;
 163         int option;
 164
 165         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 166
 167         if(nfd < 0) {
 168                 logger(mesh, MESHLINK_ERROR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
 169                 return -1;
 170         }
 171
 172 #ifdef FD_CLOEXEC
 173         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 174 #endif
 175
 176 #ifdef O_NONBLOCK
 177         {
 178                 int flags = fcntl(nfd, F_GETFL);
 179
 180                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
 181                         closesocket(nfd);
 182                         logger(mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "fcntl",
 183                                strerror(errno));
 184                         return -1;
 185                 }
 186         }
 187 #elif defined(WIN32)
 188         {
 189                 unsigned long arg = 1;
 190
 191                 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
 192                         closesocket(nfd);
 193                         logger(mesh, MESHLINK_ERROR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
 194                         return -1;
 195                 }
 196         }
 197 #endif
 198
 199         option = 1;
 200         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
 201         setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof(option));
 202
 203 #if defined(IPV6_V6ONLY)
 204
 205         if(sa->sa.sa_family == AF_INET6) {
 206                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
 207         }
 208
 209 #endif
 210
 211 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
 212 #define IP_DONTFRAGMENT IP_DONTFRAG
 213 #endif
 214
 215 #if defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 216
 217         if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
 218                 option = IP_PMTUDISC_DO;
 219                 setsockopt(nfd, IPPROTO_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
 220         }
 221
 222 #elif defined(IP_DONTFRAGMENT)
 223
 224         if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
 225                 option = 1;
 226                 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
 227         }
 228
 229 #else
 230 #warning No way to disable IPv4 fragmentation
 231 #endif
 232
 233 #if defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 234
 235         if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
 236                 option = IPV6_PMTUDISC_DO;
 237                 setsockopt(nfd, IPPROTO_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
 238         }
 239
 240 #elif defined(IPV6_DONTFRAG)
 241
 242         if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
 243                 option = 1;
 244                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
 245         }
 246
 247 #else
 248 #warning No way to disable IPv6 fragmentation
 249 #endif
 250
 251         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 252                 closesocket(nfd);
 253                 addrstr = sockaddr2hostname(sa);
 254                 logger(mesh, MESHLINK_ERROR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
 255                 free(addrstr);
 256                 return -1;
 257         }
 258
 259         return nfd;
 260 } /* int setup_vpn_in_socket */
 261
 262 static void retry_outgoing_handler(event_loop_t *loop, void *data) {
 263         meshlink_handle_t *mesh = loop->data;
 264         outgoing_t *outgoing = data;
 265         setup_outgoing_connection(mesh, outgoing);
 266 }
 267
 268 void retry_outgoing(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 269         outgoing->timeout += 5;
 270
 271         if(outgoing->timeout > mesh->maxtimeout) {
 272                 outgoing->timeout = mesh->maxtimeout;
 273         }
 274
 275         timeout_add(&mesh->loop, &outgoing->ev, retry_outgoing_handler, outgoing, &(struct timeval) {
 276                 outgoing->timeout, rand() % 100000
 277         });
 278
 279         logger(mesh, MESHLINK_INFO, "Trying to re-establish outgoing connection in %d seconds", outgoing->timeout);
 280 }
 281
 282 void finish_connecting(meshlink_handle_t *mesh, connection_t *c) {
 283         logger(mesh, MESHLINK_INFO, "Connected to %s", c->name);
 284
 285         c->last_ping_time = mesh->loop.now.tv_sec;
 286         c->status.connecting = false;
 287
 288         send_id(mesh, c);
 289 }
 290
 291 static void handle_meta_write(meshlink_handle_t *mesh, connection_t *c) {
 292         if(c->outbuf.len <= c->outbuf.offset) {
 293                 return;
 294         }
 295
 296         ssize_t outlen = send(c->socket, c->outbuf.data + c->outbuf.offset, c->outbuf.len - c->outbuf.offset, MSG_NOSIGNAL);
 297
 298         if(outlen <= 0) {
 299                 if(!errno || errno == EPIPE) {
 300                         logger(mesh, MESHLINK_INFO, "Connection closed by %s", c->name);
 301                 } else if(sockwouldblock(sockerrno)) {
 302                         logger(mesh, MESHLINK_DEBUG, "Sending %lu bytes to %s would block", (unsigned long)(c->outbuf.len - c->outbuf.offset), c->name);
 303                         return;
 304                 } else {
 305                         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));
 306                 }
 307
 308                 terminate_connection(mesh, c, c->status.active);
 309                 return;
 310         }
 311
 312         buffer_read(&c->outbuf, outlen);
 313
 314         if(!c->outbuf.len) {
 315                 io_set(&mesh->loop, &c->io, IO_READ);
 316         }
 317 }
 318
 319 static void handle_meta_io(event_loop_t *loop, void *data, int flags) {
 320         meshlink_handle_t *mesh = loop->data;
 321         connection_t *c = data;
 322
 323         if(c->status.connecting) {
 324                 c->status.connecting = false;
 325
 326                 int result;
 327                 socklen_t len = sizeof(result);
 328                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&result, &len);
 329
 330                 if(!result) {
 331                         finish_connecting(mesh, c);
 332                 } else {
 333                         logger(mesh, MESHLINK_DEBUG, "Error while connecting to %s: %s", c->name, sockstrerror(result));
 334                         terminate_connection(mesh, c, false);
 335                         return;
 336                 }
 337         }
 338
 339         if(flags & IO_WRITE) {
 340                 handle_meta_write(mesh, c);
 341         } else {
 342                 handle_meta_connection_data(mesh, c);
 343         }
 344 }
 345
 346 // Find edges pointing to this node, and use them to build a list of unique, known addresses.
 347 static struct addrinfo *get_known_addresses(node_t *n) {
 348         struct addrinfo *ai = NULL;
 349
 350         for splay_each(edge_t, e, n->edge_tree) {
 351                 if(!e->reverse) {
 352                         continue;
 353                 }
 354
 355                 bool found = false;
 356
 357                 for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
 358                         if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
 359                                 found = true;
 360                                 break;
 361                         }
 362                 }
 363
 364                 if(found) {
 365                         continue;
 366                 }
 367
 368                 // Create a new struct addrinfo, and put it at the head of the list.
 369                 struct addrinfo *nai = xzalloc(sizeof(*nai) + SALEN(e->reverse->address.sa));
 370                 nai->ai_next = ai;
 371                 ai = nai;
 372
 373                 ai->ai_family = e->reverse->address.sa.sa_family;
 374                 ai->ai_socktype = SOCK_STREAM;
 375                 ai->ai_protocol = IPPROTO_TCP;
 376                 ai->ai_addrlen = SALEN(e->reverse->address.sa);
 377                 ai->ai_addr = (struct sockaddr *)(nai + 1);
 378                 memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
 379         }
 380
 381         return ai;
 382 }
 383
 384 // Build a list of recently seen addresses.
 385 static struct addrinfo *get_recent_addresses(node_t *n) {
 386         struct addrinfo *ai = NULL;
 387         struct addrinfo *aip;
 388
 389         for(int i = 0; i < 5; i++) {
 390                 if(!n->recent[i].sa.sa_family) {
 391                         break;
 392                 }
 393
 394                 // Create a new struct addrinfo, and put it at the end of the list.
 395                 struct addrinfo *nai = xzalloc(sizeof(*nai) + SALEN(n->recent[i].sa));
 396
 397                 if(!ai) {
 398                         ai = nai;
 399                 } else {
 400                         aip->ai_next = nai;
 401                 }
 402
 403                 aip = nai;
 404
 405                 nai->ai_family = n->recent[i].sa.sa_family;
 406                 nai->ai_socktype = SOCK_STREAM;
 407                 nai->ai_protocol = IPPROTO_TCP;
 408                 nai->ai_addrlen = SALEN(n->recent[i].sa);
 409                 nai->ai_addr = (struct sockaddr *)(nai + 1);
 410                 memcpy(nai->ai_addr, &n->recent[i], nai->ai_addrlen);
 411         }
 412
 413         return ai;
 414 }
 415
 416 // Free struct addrinfo list from get_known_addresses().
 417 static void free_known_addresses(struct addrinfo *ai) {
 418         for(struct addrinfo *aip = ai, *next; aip; aip = next) {
 419                 next = aip->ai_next;
 420                 free(aip);
 421         }
 422 }
 423
 424 static struct addrinfo *get_canonical_address(node_t *n) {
 425         if(!n->canonical_address) {
 426                 return false;
 427         }
 428
 429         char *address = xstrdup(n->canonical_address);
 430         char *port = strchr(address, ' ');
 431
 432         if(!port) {
 433                 free(address);
 434                 return false;
 435         }
 436
 437         *port++ = 0;
 438
 439         struct addrinfo *ai = str2addrinfo(address, port, SOCK_STREAM);
 440         free(address);
 441
 442         return ai;
 443 }
 444
 445 static bool get_next_outgoing_address(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 446         (void)mesh;
 447
 448         bool start = false;
 449
 450         if(outgoing->state == OUTGOING_START) {
 451                 start = true;
 452                 outgoing->state = OUTGOING_CANONICAL;
 453         }
 454
 455         if(outgoing->state == OUTGOING_CANONICAL) {
 456                 if(!outgoing->aip) {
 457                         outgoing->ai = get_canonical_address(outgoing->node);
 458                         outgoing->aip = outgoing->ai;
 459                 } else {
 460                         outgoing->aip = outgoing->aip->ai_next;
 461                 }
 462
 463                 if(outgoing->aip) {
 464                         return true;
 465                 }
 466
 467                 freeaddrinfo(outgoing->ai);
 468                 outgoing->ai = NULL;
 469                 outgoing->aip = NULL;
 470                 outgoing->state = OUTGOING_RECENT;
 471         }
 472
 473         if(outgoing->state == OUTGOING_RECENT) {
 474                 if(!outgoing->aip) {
 475                         outgoing->ai = get_recent_addresses(outgoing->node);
 476                         outgoing->aip = outgoing->ai;
 477                 } else {
 478                         outgoing->aip = outgoing->aip->ai_next;
 479                 }
 480
 481                 if(outgoing->aip) {
 482                         return true;
 483                 }
 484
 485                 free_known_addresses(outgoing->ai);
 486                 outgoing->ai = NULL;
 487                 outgoing->aip = NULL;
 488                 outgoing->state = OUTGOING_KNOWN;
 489         }
 490
 491         if(outgoing->state == OUTGOING_KNOWN) {
 492                 if(!outgoing->aip) {
 493                         outgoing->ai = get_known_addresses(outgoing->node);
 494                         outgoing->aip = outgoing->ai;
 495                 } else {
 496                         outgoing->aip = outgoing->aip->ai_next;
 497                 }
 498
 499                 if(outgoing->aip) {
 500                         return true;
 501                 }
 502
 503                 free_known_addresses(outgoing->ai);
 504                 outgoing->ai = NULL;
 505                 outgoing->aip = NULL;
 506                 outgoing->state = OUTGOING_END;
 507         }
 508
 509         if(start) {
 510                 outgoing->state = OUTGOING_NO_KNOWN_ADDRESSES;
 511         }
 512
 513         return false;
 514 }
 515
 516 bool do_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 517         struct addrinfo *proxyai = NULL;
 518         int result;
 519
 520 begin:
 521
 522         if(!get_next_outgoing_address(mesh, outgoing)) {
 523                 if(outgoing->state == OUTGOING_NO_KNOWN_ADDRESSES) {
 524                         logger(mesh, MESHLINK_ERROR, "No known addresses for %s", outgoing->node->name);
 525                 } else {
 526                         logger(mesh, MESHLINK_ERROR, "Could not set up a meta connection to %s", outgoing->node->name);
 527                         retry_outgoing(mesh, outgoing);
 528                 }
 529
 530                 return false;
 531         }
 532
 533         connection_t *c = new_connection();
 534         c->outgoing = outgoing;
 535
 536         memcpy(&c->address, outgoing->aip->ai_addr, outgoing->aip->ai_addrlen);
 537
 538         char *hostname = sockaddr2hostname(&c->address);
 539
 540         logger(mesh, MESHLINK_INFO, "Trying to connect to %s at %s", outgoing->node->name, hostname);
 541
 542         if(!mesh->proxytype) {
 543                 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 544                 configure_tcp(c);
 545         } else {
 546                 proxyai = str2addrinfo(mesh->proxyhost, mesh->proxyport, SOCK_STREAM);
 547
 548                 if(!proxyai) {
 549                         free_connection(c);
 550                         free(hostname);
 551                         goto begin;
 552                 }
 553
 554                 logger(mesh, MESHLINK_INFO, "Using proxy at %s port %s", mesh->proxyhost, mesh->proxyport);
 555                 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
 556                 configure_tcp(c);
 557         }
 558
 559         if(c->socket == -1) {
 560                 logger(mesh, MESHLINK_ERROR, "Creating socket for %s at %s failed: %s", c->name, hostname, sockstrerror(sockerrno));
 561                 free_connection(c);
 562                 free(hostname);
 563                 goto begin;
 564         }
 565
 566         free(hostname);
 567
 568 #ifdef FD_CLOEXEC
 569         fcntl(c->socket, F_SETFD, FD_CLOEXEC);
 570 #endif
 571
 572 #if defined(IPV6_V6ONLY)
 573
 574         if(c->address.sa.sa_family == AF_INET6) {
 575                 static const int option = 1;
 576                 setsockopt(c->socket, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
 577         }
 578
 579 #endif
 580
 581         bind_to_address(mesh, c);
 582
 583         /* Connect */
 584
 585         if(!mesh->proxytype) {
 586                 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 587         } else {
 588                 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
 589                 freeaddrinfo(proxyai);
 590         }
 591
 592         if(result == -1 && !sockinprogress(sockerrno)) {
 593                 logger(mesh, MESHLINK_ERROR, "Could not connect to %s: %s", outgoing->node->name, sockstrerror(sockerrno));
 594                 free_connection(c);
 595
 596                 goto begin;
 597         }
 598
 599         /* Now that there is a working socket, fill in the rest and register this connection. */
 600
 601         c->status.connecting = true;
 602         c->name = xstrdup(outgoing->node->name);
 603         c->last_ping_time = mesh->loop.now.tv_sec;
 604
 605         connection_add(mesh, c);
 606
 607         io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ | IO_WRITE);
 608
 609         return true;
 610 }
 611
 612 void setup_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 613         timeout_del(&mesh->loop, &outgoing->ev);
 614
 615         if(outgoing->node->connection) {
 616                 logger(mesh, MESHLINK_INFO, "Already connected to %s", outgoing->node->name);
 617
 618                 outgoing->node->connection->outgoing = outgoing;
 619                 return;
 620         }
 621
 622
 623         if(outgoing->ai) {
 624                 if(outgoing->state == OUTGOING_RECENT || outgoing->state == OUTGOING_KNOWN) {
 625                         free_known_addresses(outgoing->ai);
 626                 } else {
 627                         freeaddrinfo(outgoing->ai);
 628                 }
 629         }
 630
 631         outgoing->state = OUTGOING_START;
 632
 633         if(outgoing->node->status.blacklisted) {
 634                 return;
 635         }
 636
 637         if(mesh->connection_try_cb) {
 638                 mesh->connection_try_cb(mesh, (meshlink_node_t *)outgoing->node);
 639         }
 640
 641         do_outgoing_connection(mesh, outgoing);
 642 }
 643
 644 /// Delayed close of a filedescriptor.
 645 static void tarpit(int fd) {
 646         static int pits[10] = {-1, -1, -1, -1, -1, -1, -1, -1, -1, -1};
 647         static int next_pit = 0;
 648
 649         if(pits[next_pit] != -1) {
 650                 closesocket(pits[next_pit]);
 651         }
 652
 653         pits[next_pit++] = fd;
 654
 655         if(next_pit >= (int)(sizeof pits / sizeof pits[0])) {
 656                 next_pit = 0;
 657         }
 658 }
 659
 660 /*
 661   accept a new tcp connect and create a
 662   new connection
 663 */
 664 void handle_new_meta_connection(event_loop_t *loop, void *data, int flags) {
 665         (void)flags;
 666         meshlink_handle_t *mesh = loop->data;
 667         listen_socket_t *l = data;
 668         connection_t *c;
 669         sockaddr_t sa;
 670         int fd;
 671         socklen_t len = sizeof(sa);
 672
 673         memset(&sa, 0, sizeof(sa));
 674
 675         fd = accept(l->tcp.fd, &sa.sa, &len);
 676
 677         if(fd < 0) {
 678                 if(errno == EINVAL) { // TODO: check if Windows agrees
 679                         event_loop_stop(loop);
 680                         return;
 681                 }
 682
 683                 logger(mesh, MESHLINK_ERROR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 684                 return;
 685         }
 686
 687         sockaddrunmap(&sa);
 688
 689         /* Rate limit incoming connections to max_connection_burst/second. */
 690
 691         static int connection_burst;
 692         static int connection_burst_time;
 693
 694         if(mesh->loop.now.tv_sec != connection_burst_time) {
 695                 connection_burst_time = mesh->loop.now.tv_sec;
 696                 connection_burst = 0;
 697         }
 698
 699         if(connection_burst >= max_connection_burst) {
 700                 tarpit(fd);
 701                 return;
 702         }
 703
 704         connection_burst++;
 705
 706         // Accept the new connection
 707
 708         c = new_connection();
 709         c->name = xstrdup("<unknown>");
 710
 711         c->address = sa;
 712         c->socket = fd;
 713         c->last_ping_time = mesh->loop.now.tv_sec;
 714
 715         char *hostname = sockaddr2hostname(&sa);
 716         logger(mesh, MESHLINK_INFO, "Connection from %s", hostname);
 717         free(hostname);
 718
 719         io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ);
 720
 721         configure_tcp(c);
 722
 723         connection_add(mesh, c);
 724
 725         c->allow_request = ID;
 726         send_id(mesh, c);
 727 }
 728
 729 static void free_outgoing(outgoing_t *outgoing) {
 730         meshlink_handle_t *mesh = outgoing->node->mesh;
 731
 732         timeout_del(&mesh->loop, &outgoing->ev);
 733
 734         if(outgoing->ai) {
 735                 if(outgoing->state == OUTGOING_RECENT || outgoing->state == OUTGOING_KNOWN) {
 736                         free_known_addresses(outgoing->ai);
 737                 } else {
 738                         freeaddrinfo(outgoing->ai);
 739                 }
 740         }
 741
 742         free(outgoing);
 743 }
 744
 745 void init_outgoings(meshlink_handle_t *mesh) {
 746         mesh->outgoings = list_alloc((list_action_t)free_outgoing);
 747 }
 748
 749 void exit_outgoings(meshlink_handle_t *mesh) {
 750         if(mesh->outgoings) {
 751                 list_delete_list(mesh->outgoings);
 752                 mesh->outgoings = NULL;
 753         }
 754 }