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