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

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