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 static const int max_connection_burst = 100;
  44
  45 /* Setup sockets */
  46
  47 static void configure_tcp(connection_t *c) {
  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(c->mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "fcntl", strerror(errno));
  53         }
  54
  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         }
  61
  62 #endif
  63
  64 #if defined(SOL_TCP) && defined(TCP_NODELAY)
  65         int nodelay = 1;
  66         setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&nodelay, sizeof(nodelay));
  67 #endif
  68
  69 #if defined(IP_TOS) && defined(IPTOS_LOWDELAY)
  70         int lowdelay = IPTOS_LOWDELAY;
  71         setsockopt(c->socket, IPPROTO_IP, IP_TOS, (void *)&lowdelay, sizeof(lowdelay));
  72 #endif
  73 }
  74
  75 static bool bind_to_address(meshlink_handle_t *mesh, connection_t *c) {
  76         int s = -1;
  77
  78         for(int i = 0; i < mesh->listen_sockets && mesh->listen_socket[i].bindto; i++) {
  79                 if(mesh->listen_socket[i].sa.sa.sa_family != c->address.sa.sa_family) {
  80                         continue;
  81                 }
  82
  83                 if(s >= 0) {
  84                         return false;
  85                 }
  86
  87                 s = i;
  88         }
  89
  90         if(s < 0) {
  91                 return false;
  92         }
  93
  94         sockaddr_t sa = mesh->listen_socket[s].sa;
  95
  96         if(sa.sa.sa_family == AF_INET) {
  97                 sa.in.sin_port = 0;
  98         } else if(sa.sa.sa_family == AF_INET6) {
  99                 sa.in6.sin6_port = 0;
 100         }
 101
 102         if(bind(c->socket, &sa.sa, SALEN(sa.sa))) {
 103                 logger(mesh, MESHLINK_WARNING, "Can't bind outgoing socket: %s", strerror(errno));
 104                 return false;
 105         }
 106
 107         return true;
 108 }
 109
 110 int setup_listen_socket(const sockaddr_t *sa) {
 111         int nfd;
 112         char *addrstr;
 113         int option;
 114
 115         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 116
 117         if(nfd < 0) {
 118                 logger(NULL, MESHLINK_ERROR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
 119                 return -1;
 120         }
 121
 122 #ifdef FD_CLOEXEC
 123         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 124 #endif
 125
 126         /* Optimize TCP settings */
 127
 128         option = 1;
 129         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
 130
 131 #if defined(IPV6_V6ONLY)
 132
 133         if(sa->sa.sa_family == AF_INET6) {
 134                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
 135         }
 136
 137 #else
 138 #warning IPV6_V6ONLY not defined
 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(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(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 214         option = IP_PMTUDISC_DO;
 215         setsockopt(nfd, IPPROTO_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
 216 #elif defined(IP_DONTFRAGMENT)
 217         option = 1;
 218         setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
 219 #endif
 220
 221 #if defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 222         option = IPV6_PMTUDISC_DO;
 223         setsockopt(nfd, IPPROTO_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
 224 #elif defined(IPV6_DONTFRAG)
 225         option = 1;
 226         setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
 227 #endif
 228
 229         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 230                 closesocket(nfd);
 231                 addrstr = sockaddr2hostname(sa);
 232                 logger(mesh, MESHLINK_ERROR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
 233                 free(addrstr);
 234                 return -1;
 235         }
 236
 237         return nfd;
 238 } /* int setup_vpn_in_socket */
 239
 240 static void retry_outgoing_handler(event_loop_t *loop, void *data) {
 241         assert(data);
 242
 243         meshlink_handle_t *mesh = loop->data;
 244         outgoing_t *outgoing = data;
 245         setup_outgoing_connection(mesh, outgoing);
 246 }
 247
 248 void retry_outgoing(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 249         if(!mesh->reachable && mesh->loop.now.tv_sec < mesh->last_unreachable + mesh->dev_class_traits[mesh->devclass].fast_retry_period) {
 250                 outgoing->timeout = 1;
 251         } else {
 252                 outgoing->timeout += 5;
 253         }
 254
 255         if(outgoing->timeout > mesh->maxtimeout) {
 256                 outgoing->timeout = mesh->maxtimeout;
 257         }
 258
 259         timeout_add(&mesh->loop, &outgoing->ev, retry_outgoing_handler, outgoing, &(struct timeval) {
 260                 outgoing->timeout, prng(mesh, TIMER_FUDGE)
 261         });
 262
 263         logger(mesh, MESHLINK_INFO, "Trying to re-establish outgoing connection in %d seconds", outgoing->timeout);
 264 }
 265
 266 void finish_connecting(meshlink_handle_t *mesh, connection_t *c) {
 267         logger(mesh, MESHLINK_INFO, "Connected to %s", c->name);
 268
 269         c->last_ping_time = mesh->loop.now.tv_sec;
 270         c->status.connecting = false;
 271
 272         send_id(mesh, c);
 273 }
 274
 275 static void handle_meta_write(meshlink_handle_t *mesh, connection_t *c) {
 276         if(c->outbuf.len <= c->outbuf.offset) {
 277                 return;
 278         }
 279
 280         ssize_t outlen = send(c->socket, c->outbuf.data + c->outbuf.offset, c->outbuf.len - c->outbuf.offset, MSG_NOSIGNAL);
 281
 282         if(outlen <= 0) {
 283                 if(!errno || errno == EPIPE) {
 284                         logger(mesh, MESHLINK_INFO, "Connection closed by %s", c->name);
 285                 } else if(sockwouldblock(sockerrno)) {
 286                         logger(mesh, MESHLINK_DEBUG, "Sending %lu bytes to %s would block", (unsigned long)(c->outbuf.len - c->outbuf.offset), c->name);
 287                         return;
 288                 } else {
 289                         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));
 290                 }
 291
 292                 terminate_connection(mesh, c, c->status.active);
 293                 return;
 294         }
 295
 296         buffer_read(&c->outbuf, outlen);
 297
 298         if(!c->outbuf.len) {
 299                 io_set(&mesh->loop, &c->io, IO_READ);
 300         }
 301 }
 302
 303 static void handle_meta_io(event_loop_t *loop, void *data, int flags) {
 304         meshlink_handle_t *mesh = loop->data;
 305         connection_t *c = data;
 306
 307         if(c->status.connecting) {
 308                 c->status.connecting = false;
 309
 310                 int result;
 311                 socklen_t len = sizeof(result);
 312                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&result, &len);
 313
 314                 if(!result) {
 315                         finish_connecting(mesh, c);
 316                 } else {
 317                         logger(mesh, MESHLINK_DEBUG, "Error while connecting to %s: %s", c->name, sockstrerror(result));
 318                         terminate_connection(mesh, c, false);
 319                         return;
 320                 }
 321         }
 322
 323         if(flags & IO_WRITE) {
 324                 handle_meta_write(mesh, c);
 325         } else {
 326                 handle_meta_connection_data(mesh, c);
 327         }
 328 }
 329
 330 // Find edges pointing to this node, and use them to build a list of unique, known addresses.
 331 static struct addrinfo *get_known_addresses(node_t *n) {
 332         struct addrinfo *ai = NULL;
 333
 334         for splay_each(edge_t, e, n->edge_tree) {
 335                 if(!e->reverse) {
 336                         continue;
 337                 }
 338
 339                 bool found = false;
 340
 341                 for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
 342                         if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
 343                                 found = true;
 344                                 break;
 345                         }
 346                 }
 347
 348                 if(found) {
 349                         continue;
 350                 }
 351
 352                 // Create a new struct addrinfo, and put it at the head of the list.
 353                 struct addrinfo *nai = xzalloc(sizeof(*nai) + SALEN(e->reverse->address.sa));
 354                 nai->ai_next = ai;
 355                 ai = nai;
 356
 357                 ai->ai_family = e->reverse->address.sa.sa_family;
 358                 ai->ai_socktype = SOCK_STREAM;
 359                 ai->ai_protocol = IPPROTO_TCP;
 360                 ai->ai_addrlen = SALEN(e->reverse->address.sa);
 361                 ai->ai_addr = (struct sockaddr *)(nai + 1);
 362                 memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
 363         }
 364
 365         return ai;
 366 }
 367
 368 // Build a list of recently seen addresses.
 369 static struct addrinfo *get_recent_addresses(node_t *n) {
 370         struct addrinfo *ai = NULL;
 371         struct addrinfo *aip;
 372
 373         for(int i = 0; i < 5; i++) {
 374                 if(!n->recent[i].sa.sa_family) {
 375                         break;
 376                 }
 377
 378                 // Create a new struct addrinfo, and put it at the end of the list.
 379                 struct addrinfo *nai = xzalloc(sizeof(*nai) + SALEN(n->recent[i].sa));
 380
 381                 if(!ai) {
 382                         ai = nai;
 383                 } else {
 384                         aip->ai_next = nai;
 385                 }
 386
 387                 aip = nai;
 388
 389                 nai->ai_family = n->recent[i].sa.sa_family;
 390                 nai->ai_socktype = SOCK_STREAM;
 391                 nai->ai_protocol = IPPROTO_TCP;
 392                 nai->ai_addrlen = SALEN(n->recent[i].sa);
 393                 nai->ai_addr = (struct sockaddr *)(nai + 1);
 394                 memcpy(nai->ai_addr, &n->recent[i], nai->ai_addrlen);
 395         }
 396
 397         return ai;
 398 }
 399
 400 // Free struct addrinfo list from get_known_addresses().
 401 static void free_known_addresses(struct addrinfo *ai) {
 402         for(struct addrinfo *aip = ai, *next; aip; aip = next) {
 403                 next = aip->ai_next;
 404                 free(aip);
 405         }
 406 }
 407
 408 static struct addrinfo *get_canonical_address(node_t *n) {
 409         if(!n->canonical_address) {
 410                 return false;
 411         }
 412
 413         char *address = xstrdup(n->canonical_address);
 414         char *port = strchr(address, ' ');
 415
 416         if(!port) {
 417                 free(address);
 418                 return false;
 419         }
 420
 421         *port++ = 0;
 422
 423         struct addrinfo *ai = str2addrinfo(address, port, SOCK_STREAM);
 424         free(address);
 425
 426         return ai;
 427 }
 428
 429 static bool get_next_outgoing_address(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 430         (void)mesh;
 431
 432         bool start = false;
 433
 434         if(outgoing->state == OUTGOING_START) {
 435                 start = true;
 436                 outgoing->state = OUTGOING_CANONICAL;
 437         }
 438
 439         if(outgoing->state == OUTGOING_CANONICAL) {
 440                 if(!outgoing->aip) {
 441                         outgoing->ai = get_canonical_address(outgoing->node);
 442                         outgoing->aip = outgoing->ai;
 443                 } else {
 444                         outgoing->aip = outgoing->aip->ai_next;
 445                 }
 446
 447                 if(outgoing->aip) {
 448                         return true;
 449                 }
 450
 451                 freeaddrinfo(outgoing->ai);
 452                 outgoing->ai = NULL;
 453                 outgoing->aip = NULL;
 454                 outgoing->state = OUTGOING_RECENT;
 455         }
 456
 457         if(outgoing->state == OUTGOING_RECENT) {
 458                 if(!outgoing->aip) {
 459                         outgoing->ai = get_recent_addresses(outgoing->node);
 460                         outgoing->aip = outgoing->ai;
 461                 } else {
 462                         outgoing->aip = outgoing->aip->ai_next;
 463                 }
 464
 465                 if(outgoing->aip) {
 466                         return true;
 467                 }
 468
 469                 free_known_addresses(outgoing->ai);
 470                 outgoing->ai = NULL;
 471                 outgoing->aip = NULL;
 472                 outgoing->state = OUTGOING_KNOWN;
 473         }
 474
 475         if(outgoing->state == OUTGOING_KNOWN) {
 476                 if(!outgoing->aip) {
 477                         outgoing->ai = get_known_addresses(outgoing->node);
 478                         outgoing->aip = outgoing->ai;
 479                 } else {
 480                         outgoing->aip = outgoing->aip->ai_next;
 481                 }
 482
 483                 if(outgoing->aip) {
 484                         return true;
 485                 }
 486
 487                 free_known_addresses(outgoing->ai);
 488                 outgoing->ai = NULL;
 489                 outgoing->aip = NULL;
 490                 outgoing->state = OUTGOING_END;
 491         }
 492
 493         if(start) {
 494                 outgoing->state = OUTGOING_NO_KNOWN_ADDRESSES;
 495         }
 496
 497         return false;
 498 }
 499
 500 void do_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 501         struct addrinfo *proxyai = NULL;
 502         int result;
 503
 504 begin:
 505
 506         if(!get_next_outgoing_address(mesh, outgoing)) {
 507                 if(outgoing->state == OUTGOING_NO_KNOWN_ADDRESSES) {
 508                         logger(mesh, MESHLINK_ERROR, "No known addresses for %s", outgoing->node->name);
 509                 } else {
 510                         logger(mesh, MESHLINK_ERROR, "Could not set up a meta connection to %s", outgoing->node->name);
 511                         retry_outgoing(mesh, outgoing);
 512                 }
 513
 514                 return;
 515         }
 516
 517         connection_t *c = new_connection();
 518         c->outgoing = outgoing;
 519
 520         memcpy(&c->address, outgoing->aip->ai_addr, outgoing->aip->ai_addrlen);
 521
 522         char *hostname = sockaddr2hostname(&c->address);
 523
 524         logger(mesh, MESHLINK_INFO, "Trying to connect to %s at %s", outgoing->node->name, hostname);
 525
 526         if(!mesh->proxytype) {
 527                 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 528                 configure_tcp(c);
 529         } else {
 530                 proxyai = str2addrinfo(mesh->proxyhost, mesh->proxyport, SOCK_STREAM);
 531
 532                 if(!proxyai) {
 533                         free_connection(c);
 534                         free(hostname);
 535                         goto begin;
 536                 }
 537
 538                 logger(mesh, MESHLINK_INFO, "Using proxy at %s port %s", mesh->proxyhost, mesh->proxyport);
 539                 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
 540                 configure_tcp(c);
 541         }
 542
 543         if(c->socket == -1) {
 544                 logger(mesh, MESHLINK_ERROR, "Creating socket for %s at %s failed: %s", c->name, hostname, sockstrerror(sockerrno));
 545                 free_connection(c);
 546                 free(hostname);
 547                 goto begin;
 548         }
 549
 550         free(hostname);
 551
 552 #ifdef FD_CLOEXEC
 553         fcntl(c->socket, F_SETFD, FD_CLOEXEC);
 554 #endif
 555
 556 #if defined(IPV6_V6ONLY)
 557
 558         if(c->address.sa.sa_family == AF_INET6) {
 559                 static const int option = 1;
 560                 setsockopt(c->socket, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
 561         }
 562
 563 #endif
 564
 565         bind_to_address(mesh, c);
 566
 567         /* Connect */
 568
 569         if(!mesh->proxytype) {
 570                 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 571         } else {
 572                 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
 573                 freeaddrinfo(proxyai);
 574         }
 575
 576         if(result == -1 && !sockinprogress(sockerrno)) {
 577                 logger(mesh, MESHLINK_ERROR, "Could not connect to %s: %s", outgoing->node->name, sockstrerror(sockerrno));
 578                 free_connection(c);
 579
 580                 goto begin;
 581         }
 582
 583         /* Now that there is a working socket, fill in the rest and register this connection. */
 584
 585         c->status.connecting = true;
 586         c->status.initiator = true;
 587         c->name = xstrdup(outgoing->node->name);
 588         c->last_ping_time = mesh->loop.now.tv_sec;
 589
 590         connection_add(mesh, c);
 591
 592         io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ | IO_WRITE);
 593 }
 594
 595 void reset_outgoing(outgoing_t *outgoing) {
 596         if(outgoing->ai) {
 597                 if(outgoing->state == OUTGOING_RECENT || outgoing->state == OUTGOING_KNOWN) {
 598                         free_known_addresses(outgoing->ai);
 599                 } else {
 600                         freeaddrinfo(outgoing->ai);
 601                 }
 602         }
 603
 604         outgoing->ai = NULL;
 605         outgoing->aip = NULL;
 606         outgoing->state = OUTGOING_START;
 607 }
 608
 609 void setup_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
 610         timeout_del(&mesh->loop, &outgoing->ev);
 611
 612         if(outgoing->node->connection) {
 613                 logger(mesh, MESHLINK_INFO, "Already connected to %s", outgoing->node->name);
 614
 615                 outgoing->node->connection->outgoing = outgoing;
 616                 return;
 617         }
 618
 619         reset_outgoing(outgoing);
 620
 621         if(outgoing->node->status.blacklisted) {
 622                 return;
 623         }
 624
 625         if(mesh->connection_try_cb) {
 626                 mesh->connection_try_cb(mesh, (meshlink_node_t *)outgoing->node);
 627         }
 628
 629         do_outgoing_connection(mesh, outgoing);
 630 }
 631
 632 /// Delayed close of a filedescriptor.
 633 static void tarpit(meshlink_handle_t *mesh, int fd) {
 634         if(!fd) {
 635                 return;
 636         }
 637
 638         if(mesh->pits[mesh->next_pit]) {
 639                 closesocket(mesh->pits[mesh->next_pit]);
 640         }
 641
 642         mesh->pits[mesh->next_pit++] = fd;
 643
 644         if(mesh->next_pit >= (int)(sizeof mesh->pits / sizeof mesh->pits[0])) {
 645                 mesh->next_pit = 0;
 646         }
 647 }
 648
 649 /*
 650   accept a new tcp connect and create a
 651   new connection
 652 */
 653 void handle_new_meta_connection(event_loop_t *loop, void *data, int flags) {
 654         (void)flags;
 655         meshlink_handle_t *mesh = loop->data;
 656         listen_socket_t *l = data;
 657         connection_t *c;
 658         sockaddr_t sa;
 659         int fd;
 660         socklen_t len = sizeof(sa);
 661
 662         memset(&sa, 0, sizeof(sa));
 663
 664         fd = accept(l->tcp.fd, &sa.sa, &len);
 665
 666         if(fd < 0) {
 667                 if(errno == EINVAL) { // TODO: check if Windows agrees
 668                         event_loop_stop(loop);
 669                         return;
 670                 }
 671
 672                 logger(mesh, MESHLINK_ERROR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 673                 return;
 674         }
 675
 676         sockaddrunmap(&sa);
 677
 678         /* Rate limit incoming connections to max_connection_burst/second. */
 679
 680         if(mesh->loop.now.tv_sec != mesh->connection_burst_time) {
 681                 mesh->connection_burst_time = mesh->loop.now.tv_sec;
 682                 mesh->connection_burst = 0;
 683         }
 684
 685         if(mesh->connection_burst >= max_connection_burst) {
 686                 tarpit(mesh, fd);
 687                 return;
 688         }
 689
 690         mesh->connection_burst++;
 691
 692         // Accept the new connection
 693
 694         c = new_connection();
 695         c->name = xstrdup("<unknown>");
 696
 697         c->address = sa;
 698         c->socket = fd;
 699         c->last_ping_time = mesh->loop.now.tv_sec;
 700
 701         char *hostname = sockaddr2hostname(&sa);
 702         logger(mesh, MESHLINK_INFO, "Connection from %s", hostname);
 703         free(hostname);
 704
 705         io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ);
 706
 707         configure_tcp(c);
 708
 709         connection_add(mesh, c);
 710
 711         c->allow_request = ID;
 712         send_id(mesh, c);
 713 }
 714
 715 static void free_outgoing(outgoing_t *outgoing) {
 716         meshlink_handle_t *mesh = outgoing->node->mesh;
 717
 718         timeout_del(&mesh->loop, &outgoing->ev);
 719
 720         if(outgoing->ai) {
 721                 if(outgoing->state == OUTGOING_RECENT || outgoing->state == OUTGOING_KNOWN) {
 722                         free_known_addresses(outgoing->ai);
 723                 } else {
 724                         freeaddrinfo(outgoing->ai);
 725                 }
 726         }
 727
 728         free(outgoing);
 729 }
 730
 731 void init_outgoings(meshlink_handle_t *mesh) {
 732         mesh->outgoings = list_alloc((list_action_t)free_outgoing);
 733 }
 734
 735 void exit_outgoings(meshlink_handle_t *mesh) {
 736         if(mesh->outgoings) {
 737                 list_delete_list(mesh->outgoings);
 738                 mesh->outgoings = NULL;
 739         }
 740 }