git.meshlink.io Git - meshlink/blob - src/net_socket.c

   1 /*
   2     net_socket.c -- Handle various kinds of sockets.
   3     Copyright (C) 1998-2005 Ivo Timmermans,
   4                   2000-2014 Guus Sliepen <guus@meshlink.io>
   5                   2006      Scott Lamb <slamb@slamb.org>
   6                   2009      Florian Forster <octo@verplant.org>
   7
   8     This program is free software; you can redistribute it and/or modify
   9     it under the terms of the GNU General Public License as published by
  10     the Free Software Foundation; either version 2 of the License, or
  11     (at your option) any later version.
  12
  13     This program is distributed in the hope that it will be useful,
  14     but WITHOUT ANY WARRANTY; without even the implied warranty of
  15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16     GNU General Public License for more details.
  17
  18     You should have received a copy of the GNU General Public License along
  19     with this program; if not, write to the Free Software Foundation, Inc.,
  20     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21 */
  22
  23 #include "system.h"
  24
  25 #include "conf.h"
  26 #include "connection.h"
  27 #include "list.h"
  28 #include "logger.h"
  29 #include "meta.h"
  30 #include "net.h"
  31 #include "netutl.h"
  32 #include "protocol.h"
  33 #include "utils.h"
  34 #include "xalloc.h"
  35
  36 /* Needed on Mac OS/X */
  37 #ifndef SOL_TCP
  38 #define SOL_TCP IPPROTO_TCP
  39 #endif
  40
  41 int addressfamily = AF_UNSPEC;
  42 int maxtimeout = 900;
  43 int seconds_till_retry = 5;
  44 int udp_rcvbuf = 0;
  45 int udp_sndbuf = 0;
  46 int max_connection_burst = 100;
  47
  48 listen_socket_t listen_socket[MAXSOCKETS];
  49 int listen_sockets;
  50 list_t *outgoing_list = NULL;
  51
  52 /* Setup sockets */
  53
  54 static void configure_tcp(connection_t *c) {
  55         int option;
  56
  57 #ifdef O_NONBLOCK
  58         int flags = fcntl(c->socket, F_GETFL);
  59
  60         if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
  61                 logger(DEBUG_ALWAYS, LOG_ERR, "fcntl for %s: %s", c->hostname, strerror(errno));
  62         }
  63 #elif defined(WIN32)
  64         unsigned long arg = 1;
  65
  66         if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
  67                 logger(DEBUG_ALWAYS, LOG_ERR, "ioctlsocket for %s: %s", c->hostname, sockstrerror(sockerrno));
  68         }
  69 #endif
  70
  71 #if defined(SOL_TCP) && defined(TCP_NODELAY)
  72         option = 1;
  73         setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&option, sizeof option);
  74 #endif
  75
  76 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
  77         option = IPTOS_LOWDELAY;
  78         setsockopt(c->socket, SOL_IP, IP_TOS, (void *)&option, sizeof option);
  79 #endif
  80 }
  81
  82 static bool bind_to_interface(int sd) {
  83         char *iface;
  84
  85 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  86         struct ifreq ifr;
  87         int status;
  88 #endif /* defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) */
  89
  90         if(!get_config_string (lookup_config (config_tree, "BindToInterface"), &iface))
  91                 return true;
  92
  93 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
  94         memset(&ifr, 0, sizeof(ifr));
  95         strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
  96         ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
  97
  98         status = setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr));
  99         if(status) {
 100                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to interface %s: %s", iface,
 101                                 strerror(errno));
 102                 return false;
 103         }
 104 #else /* if !defined(SOL_SOCKET) || !defined(SO_BINDTODEVICE) */
 105         logger(DEBUG_ALWAYS, LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 106 #endif
 107
 108         return true;
 109 }
 110
 111 static bool bind_to_address(connection_t *c) {
 112         int s = -1;
 113
 114         for(int i = 0; i < listen_sockets && listen_socket[i].bindto; i++) {
 115                 if(listen_socket[i].sa.sa.sa_family != c->address.sa.sa_family)
 116                         continue;
 117                 if(s >= 0)
 118                         return false;
 119                 s = i;
 120         }
 121
 122         if(s < 0)
 123                 return false;
 124
 125         sockaddr_t sa = listen_socket[s].sa;
 126         if(sa.sa.sa_family == AF_INET)
 127                 sa.in.sin_port = 0;
 128         else if(sa.sa.sa_family == AF_INET6)
 129                 sa.in6.sin6_port = 0;
 130
 131         if(bind(c->socket, &sa.sa, SALEN(sa.sa))) {
 132                 logger(DEBUG_CONNECTIONS, LOG_WARNING, "Can't bind outgoing socket: %s", strerror(errno));
 133                 return false;
 134         }
 135
 136         return true;
 137 }
 138
 139 int setup_listen_socket(const sockaddr_t *sa) {
 140         int nfd;
 141         char *addrstr;
 142         int option;
 143         char *iface;
 144
 145         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 146
 147         if(nfd < 0) {
 148                 logger(DEBUG_STATUS, LOG_ERR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
 149                 return -1;
 150         }
 151
 152 #ifdef FD_CLOEXEC
 153         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 154 #endif
 155
 156         /* Optimize TCP settings */
 157
 158         option = 1;
 159         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
 160
 161 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 162         if(sa->sa.sa_family == AF_INET6)
 163                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 164 #endif
 165
 166         if(get_config_string
 167            (lookup_config(config_tree, "BindToInterface"), &iface)) {
 168 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
 169                 struct ifreq ifr;
 170
 171                 memset(&ifr, 0, sizeof ifr);
 172                 strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
 173
 174                 if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof ifr)) {
 175                         closesocket(nfd);
 176                         logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to interface %s: %s", iface,
 177                                    strerror(sockerrno));
 178                         return -1;
 179                 }
 180 #else
 181                 logger(DEBUG_ALWAYS, LOG_WARNING, "%s not supported on this platform", "BindToInterface");
 182 #endif
 183         }
 184
 185         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 186                 closesocket(nfd);
 187                 addrstr = sockaddr2hostname(sa);
 188                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
 189                 free(addrstr);
 190                 return -1;
 191         }
 192
 193         if(listen(nfd, 3)) {
 194                 closesocket(nfd);
 195                 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
 196                 return -1;
 197         }
 198
 199         return nfd;
 200 }
 201
 202 int setup_vpn_in_socket(const sockaddr_t *sa) {
 203         int nfd;
 204         char *addrstr;
 205         int option;
 206
 207         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
 208
 209         if(nfd < 0) {
 210                 logger(DEBUG_ALWAYS, LOG_ERR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
 211                 return -1;
 212         }
 213
 214 #ifdef FD_CLOEXEC
 215         fcntl(nfd, F_SETFD, FD_CLOEXEC);
 216 #endif
 217
 218 #ifdef O_NONBLOCK
 219         {
 220                 int flags = fcntl(nfd, F_GETFL);
 221
 222                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
 223                         closesocket(nfd);
 224                         logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "fcntl",
 225                                    strerror(errno));
 226                         return -1;
 227                 }
 228         }
 229 #elif defined(WIN32)
 230         {
 231                 unsigned long arg = 1;
 232                 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
 233                         closesocket(nfd);
 234                         logger(DEBUG_ALWAYS, LOG_ERR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
 235                         return -1;
 236                 }
 237         }
 238 #endif
 239
 240         option = 1;
 241         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
 242         setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof option);
 243
 244         if(udp_rcvbuf && setsockopt(nfd, SOL_SOCKET, SO_RCVBUF, (void *)&udp_rcvbuf, sizeof(udp_rcvbuf)))
 245                 logger(DEBUG_ALWAYS, LOG_WARNING, "Can't set UDP SO_RCVBUF to %i: %s", udp_rcvbuf, strerror(errno));
 246
 247         if(udp_sndbuf && setsockopt(nfd, SOL_SOCKET, SO_SNDBUF, (void *)&udp_sndbuf, sizeof(udp_sndbuf)))
 248                 logger(DEBUG_ALWAYS, LOG_WARNING, "Can't set UDP SO_SNDBUF to %i: %s", udp_sndbuf, strerror(errno));
 249
 250 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
 251         if(sa->sa.sa_family == AF_INET6)
 252                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 253 #endif
 254
 255 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
 256 #define IP_DONTFRAGMENT IP_DONTFRAG
 257 #endif
 258
 259 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
 260         if(myself->options & OPTION_PMTU_DISCOVERY) {
 261                 option = IP_PMTUDISC_DO;
 262                 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
 263         }
 264 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
 265         if(myself->options & OPTION_PMTU_DISCOVERY) {
 266                 option = 1;
 267                 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
 268         }
 269 #else
 270 #warning No way to disable IPv4 fragmentation
 271 #endif
 272
 273 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
 274         if(myself->options & OPTION_PMTU_DISCOVERY) {
 275                 option = IPV6_PMTUDISC_DO;
 276                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
 277         }
 278 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
 279         if(myself->options & OPTION_PMTU_DISCOVERY) {
 280                 option = 1;
 281                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
 282         }
 283 #else
 284 #warning No way to disable IPv6 fragmentation
 285 #endif
 286
 287         if (!bind_to_interface(nfd)) {
 288                 closesocket(nfd);
 289                 return -1;
 290         }
 291
 292         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
 293                 closesocket(nfd);
 294                 addrstr = sockaddr2hostname(sa);
 295                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
 296                 free(addrstr);
 297                 return -1;
 298         }
 299
 300         return nfd;
 301 } /* int setup_vpn_in_socket */
 302
 303 static void retry_outgoing_handler(void *data) {
 304         setup_outgoing_connection(data);
 305 }
 306
 307 void retry_outgoing(outgoing_t *outgoing) {
 308         outgoing->timeout += 5;
 309
 310         if(outgoing->timeout > maxtimeout)
 311                 outgoing->timeout = maxtimeout;
 312
 313         timeout_add(&outgoing->ev, retry_outgoing_handler, outgoing, &(struct timeval){outgoing->timeout, rand() % 100000});
 314
 315         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Trying to re-establish outgoing connection in %d seconds", outgoing->timeout);
 316 }
 317
 318 void finish_connecting(connection_t *c) {
 319         logger(DEBUG_CONNECTIONS, LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
 320
 321         c->last_ping_time = now.tv_sec;
 322         c->status.connecting = false;
 323
 324         send_id(c);
 325 }
 326
 327 static void do_outgoing_pipe(connection_t *c, char *command) {
 328 #ifndef HAVE_MINGW
 329         int fd[2];
 330
 331         if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd)) {
 332                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not create socketpair: %s", strerror(errno));
 333                 return;
 334         }
 335
 336         if(fork()) {
 337                 c->socket = fd[0];
 338                 close(fd[1]);
 339                 logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Using proxy %s", command);
 340                 return;
 341         }
 342
 343         close(0);
 344         close(1);
 345         close(fd[0]);
 346         dup2(fd[1], 0);
 347         dup2(fd[1], 1);
 348         close(fd[1]);
 349
 350         // Other filedescriptors should be closed automatically by CLOEXEC
 351
 352         char *host = NULL;
 353         char *port = NULL;
 354
 355         sockaddr2str(&c->address, &host, &port);
 356         setenv("REMOTEADDRESS", host, true);
 357         setenv("REMOTEPORT", port, true);
 358         setenv("NODE", c->name, true);
 359         setenv("NAME", myself->name, true);
 360
 361         int result = system(command);
 362         if(result < 0)
 363                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not execute %s: %s", command, strerror(errno));
 364         else if(result)
 365                 logger(DEBUG_ALWAYS, LOG_ERR, "%s exited with non-zero status %d", command, result);
 366         exit(result);
 367 #else
 368         logger(DEBUG_ALWAYS, LOG_ERR, "Proxy type exec not supported on this platform!");
 369         return;
 370 #endif
 371 }
 372
 373 static void handle_meta_write(connection_t *c) {
 374         if(c->outbuf.len <= c->outbuf.offset)
 375                 return;
 376
 377         ssize_t outlen = send(c->socket, c->outbuf.data + c->outbuf.offset, c->outbuf.len - c->outbuf.offset, 0);
 378         if(outlen <= 0) {
 379                 if(!errno || errno == EPIPE) {
 380                         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection closed by %s (%s)", c->name, c->hostname);
 381                 } else if(sockwouldblock(sockerrno)) {
 382                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Sending %d bytes to %s (%s) would block", c->outbuf.len - c->outbuf.offset, c->name, c->hostname);
 383                         return;
 384                 } else {
 385                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not send %d bytes of data to %s (%s): %s", c->outbuf.len - c->outbuf.offset, c->name, c->hostname, strerror(errno));
 386                 }
 387
 388                 terminate_connection(c, c->status.active);
 389                 return;
 390         }
 391
 392         buffer_read(&c->outbuf, outlen);
 393         if(!c->outbuf.len)
 394                 io_set(&c->io, IO_READ);
 395 }
 396
 397 static void handle_meta_io(void *data, int flags) {
 398         connection_t *c = data;
 399
 400         if(c->status.connecting) {
 401                 c->status.connecting = false;
 402
 403                 int result;
 404                 socklen_t len = sizeof result;
 405                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&result, &len);
 406
 407                 if(!result)
 408                         finish_connecting(c);
 409                 else {
 410                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Error while connecting to %s (%s): %s", c->name, c->hostname, sockstrerror(result));
 411                         terminate_connection(c, false);
 412                         return;
 413                 }
 414         }
 415
 416         if(flags & IO_WRITE)
 417                 handle_meta_write(c);
 418         else
 419                 handle_meta_connection_data(c);
 420 }
 421
 422 bool do_outgoing_connection(outgoing_t *outgoing) {
 423         char *address, *port, *space;
 424         struct addrinfo *proxyai = NULL;
 425         int result;
 426
 427 begin:
 428         if(!outgoing->ai) {
 429                 if(!outgoing->cfg) {
 430                         logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not set up a meta connection to %s", outgoing->name);
 431                         retry_outgoing(outgoing);
 432                         return false;
 433                 }
 434
 435                 get_config_string(outgoing->cfg, &address);
 436
 437                 space = strchr(address, ' ');
 438                 if(space) {
 439                         port = xstrdup(space + 1);
 440                         *space = 0;
 441                 } else {
 442                         if(!get_config_string(lookup_config(outgoing->config_tree, "Port"), &port))
 443                                 port = xstrdup("655");
 444                 }
 445
 446                 outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
 447                 free(address);
 448                 free(port);
 449
 450                 outgoing->aip = outgoing->ai;
 451                 outgoing->cfg = lookup_config_next(outgoing->config_tree, outgoing->cfg);
 452         }
 453
 454         if(!outgoing->aip) {
 455                 if(outgoing->ai)
 456                         freeaddrinfo(outgoing->ai);
 457                 outgoing->ai = NULL;
 458                 goto begin;
 459         }
 460
 461         connection_t *c = new_connection();
 462         c->outgoing = outgoing;
 463
 464         memcpy(&c->address, outgoing->aip->ai_addr, outgoing->aip->ai_addrlen);
 465         outgoing->aip = outgoing->aip->ai_next;
 466
 467         c->hostname = sockaddr2hostname(&c->address);
 468
 469         logger(DEBUG_CONNECTIONS, LOG_INFO, "Trying to connect to %s (%s)", outgoing->name, c->hostname);
 470
 471         if(!proxytype) {
 472                 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
 473                 configure_tcp(c);
 474         } else if(proxytype == PROXY_EXEC) {
 475                 do_outgoing_pipe(c, proxyhost);
 476         } else {
 477                 proxyai = str2addrinfo(proxyhost, proxyport, SOCK_STREAM);
 478                 if(!proxyai) {
 479                         free_connection(c);
 480                         goto begin;
 481                 }
 482                 logger(DEBUG_CONNECTIONS, LOG_INFO, "Using proxy at %s port %s", proxyhost, proxyport);
 483                 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
 484                 configure_tcp(c);
 485         }
 486
 487         if(c->socket == -1) {
 488                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
 489                 free_connection(c);
 490                 goto begin;
 491         }
 492
 493 #ifdef FD_CLOEXEC
 494         fcntl(c->socket, F_SETFD, FD_CLOEXEC);
 495 #endif
 496
 497         if(proxytype != PROXY_EXEC) {
 498 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
 499                 int option = 1;
 500                 if(c->address.sa.sa_family == AF_INET6)
 501                         setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
 502 #endif
 503
 504                 bind_to_interface(c->socket);
 505                 bind_to_address(c);
 506         }
 507
 508         /* Connect */
 509
 510         if(!proxytype) {
 511                 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
 512         } else if(proxytype == PROXY_EXEC) {
 513                 result = 0;
 514         } else {
 515                 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
 516                 freeaddrinfo(proxyai);
 517         }
 518
 519         if(result == -1 && !sockinprogress(sockerrno)) {
 520                 logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not connect to %s (%s): %s", outgoing->name, c->hostname, sockstrerror(sockerrno));
 521                 free_connection(c);
 522
 523                 goto begin;
 524         }
 525
 526         /* Now that there is a working socket, fill in the rest and register this connection. */
 527
 528         c->status.connecting = true;
 529         c->name = xstrdup(outgoing->name);
 530         c->outcipher = myself->connection->outcipher;
 531         c->outdigest = myself->connection->outdigest;
 532         c->outmaclength = myself->connection->outmaclength;
 533         c->outcompression = myself->connection->outcompression;
 534         c->last_ping_time = now.tv_sec;
 535
 536         connection_add(c);
 537
 538         io_add(&c->io, handle_meta_io, c, c->socket, IO_READ|IO_WRITE);
 539
 540         return true;
 541 }
 542
 543 // Find edges pointing to this node, and use them to build a list of unique, known addresses.
 544 static struct addrinfo *get_known_addresses(node_t *n) {
 545         struct addrinfo *ai = NULL;
 546
 547         for splay_each(edge_t, e, n->edge_tree) {
 548                 if(!e->reverse)
 549                         continue;
 550
 551                 bool found = false;
 552                 for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
 553                         if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
 554                                 found = true;
 555                                 break;
 556                         }
 557                 }
 558                 if(found)
 559                         continue;
 560
 561                 struct addrinfo *nai = xzalloc(sizeof *nai);
 562                 if(ai)
 563                         ai->ai_next = nai;
 564                 ai = nai;
 565                 ai->ai_family = e->reverse->address.sa.sa_family;
 566                 ai->ai_socktype = SOCK_STREAM;
 567                 ai->ai_protocol = IPPROTO_TCP;
 568                 ai->ai_addrlen = SALEN(e->reverse->address.sa);
 569                 ai->ai_addr = xmalloc(ai->ai_addrlen);
 570                 memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
 571         }
 572
 573         return ai;
 574 }
 575
 576 void setup_outgoing_connection(outgoing_t *outgoing) {
 577         timeout_del(&outgoing->ev);
 578
 579         node_t *n = lookup_node(outgoing->name);
 580
 581         if(n && n->connection) {
 582                 logger(DEBUG_CONNECTIONS, LOG_INFO, "Already connected to %s", outgoing->name);
 583
 584                 n->connection->outgoing = outgoing;
 585                 return;
 586         }
 587
 588         init_configuration(&outgoing->config_tree);
 589         read_host_config(outgoing->config_tree, outgoing->name);
 590         outgoing->cfg = lookup_config(outgoing->config_tree, "Address");
 591
 592         if(!outgoing->cfg) {
 593                 if(n)
 594                         outgoing->aip = outgoing->ai = get_known_addresses(n);
 595                 if(!outgoing->ai) {
 596                         logger(DEBUG_ALWAYS, LOG_ERR, "No address known for %s", outgoing->name);
 597                         return;
 598                 }
 599         }
 600
 601         do_outgoing_connection(outgoing);
 602 }
 603
 604 /*
 605   accept a new tcp connect and create a
 606   new connection
 607 */
 608 void handle_new_meta_connection(void *data, int flags) {
 609         listen_socket_t *l = data;
 610         connection_t *c;
 611         sockaddr_t sa;
 612         int fd;
 613         socklen_t len = sizeof sa;
 614
 615         fd = accept(l->tcp.fd, &sa.sa, &len);
 616
 617         if(fd < 0) {
 618                 logger(DEBUG_ALWAYS, LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
 619                 return;
 620         }
 621
 622         sockaddrunmap(&sa);
 623
 624         // Check if we get many connections from the same host
 625
 626         static sockaddr_t prev_sa;
 627         static int tarpit = -1;
 628
 629         if(tarpit >= 0) {
 630                 closesocket(tarpit);
 631                 tarpit = -1;
 632         }
 633
 634         if(!sockaddrcmp_noport(&sa, &prev_sa)) {
 635                 static int samehost_burst;
 636                 static int samehost_burst_time;
 637
 638                 if(now.tv_sec - samehost_burst_time > samehost_burst)
 639                         samehost_burst = 0;
 640                 else
 641                         samehost_burst -= now.tv_sec - samehost_burst_time;
 642
 643                 samehost_burst_time = now.tv_sec;
 644                 samehost_burst++;
 645
 646                 if(samehost_burst > max_connection_burst) {
 647                         tarpit = fd;
 648                         return;
 649                 }
 650         }
 651
 652         memcpy(&prev_sa, &sa, sizeof sa);
 653
 654         // Check if we get many connections from different hosts
 655
 656         static int connection_burst;
 657         static int connection_burst_time;
 658
 659         if(now.tv_sec - connection_burst_time > connection_burst)
 660                 connection_burst = 0;
 661         else
 662                 connection_burst -= now.tv_sec - connection_burst_time;
 663
 664         connection_burst_time = now.tv_sec;
 665         connection_burst++;
 666
 667         if(connection_burst >= max_connection_burst) {
 668                 connection_burst = max_connection_burst;
 669                 tarpit = fd;
 670                 return;
 671         }
 672
 673         // Accept the new connection
 674
 675         c = new_connection();
 676         c->name = xstrdup("<unknown>");
 677         c->outcipher = myself->connection->outcipher;
 678         c->outdigest = myself->connection->outdigest;
 679         c->outmaclength = myself->connection->outmaclength;
 680         c->outcompression = myself->connection->outcompression;
 681
 682         c->address = sa;
 683         c->hostname = sockaddr2hostname(&sa);
 684         c->socket = fd;
 685         c->last_ping_time = now.tv_sec;
 686
 687         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection from %s", c->hostname);
 688
 689         io_add(&c->io, handle_meta_io, c, c->socket, IO_READ);
 690
 691         configure_tcp(c);
 692
 693         connection_add(c);
 694
 695         c->allow_request = ID;
 696         send_id(c);
 697 }
 698
 699 static void free_outgoing(outgoing_t *outgoing) {
 700         timeout_del(&outgoing->ev);
 701
 702         if(outgoing->ai)
 703                 freeaddrinfo(outgoing->ai);
 704
 705         if(outgoing->config_tree)
 706                 exit_configuration(&outgoing->config_tree);
 707
 708         if(outgoing->name)
 709                 free(outgoing->name);
 710
 711         free(outgoing);
 712 }
 713
 714 void try_outgoing_connections(void) {
 715         /* If there is no outgoing list yet, create one. Otherwise, mark all outgoings as deleted. */
 716
 717         if(!outgoing_list) {
 718                 outgoing_list = list_alloc((list_action_t)free_outgoing);
 719         } else {
 720                 for list_each(outgoing_t, outgoing, outgoing_list)
 721                         outgoing->timeout = -1;
 722         }
 723
 724         /* Make sure there is one outgoing_t in the list for each ConnectTo. */
 725
 726         for(config_t *cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 727                 char *name;
 728                 get_config_string(cfg, &name);
 729
 730                 if(!check_id(name)) {
 731                         logger(DEBUG_ALWAYS, LOG_ERR,
 732                                    "Invalid name for outgoing connection in %s line %d",
 733                                    cfg->file, cfg->line);
 734                         free(name);
 735                         continue;
 736                 }
 737
 738                 bool found = false;
 739
 740                 for list_each(outgoing_t, outgoing, outgoing_list) {
 741                         if(!strcmp(outgoing->name, name)) {
 742                                 found = true;
 743                                 outgoing->timeout = 0;
 744                                 break;
 745                         }
 746                 }
 747
 748                 if(!found) {
 749                         outgoing_t *outgoing = xzalloc(sizeof *outgoing);
 750                         outgoing->name = name;
 751                         list_insert_tail(outgoing_list, outgoing);
 752                         setup_outgoing_connection(outgoing);
 753                 }
 754         }
 755
 756         /* Terminate any connections whose outgoing_t is to be deleted. */
 757
 758         for list_each(connection_t, c, connection_list) {
 759                 if(c->outgoing && c->outgoing->timeout == -1) {
 760                         c->outgoing = NULL;
 761                         logger(DEBUG_CONNECTIONS, LOG_INFO, "No more outgoing connection to %s", c->name);
 762                         terminate_connection(c, c->status.active);
 763                 }
 764         }
 765
 766         /* Delete outgoing_ts for which there is no ConnectTo. */
 767
 768         for list_each(outgoing_t, outgoing, outgoing_list)
 769                 if(outgoing->timeout == -1)
 770                         list_delete_node(outgoing_list, node);
 771 }