2 net_socket.c -- Handle various kinds of sockets.
3 Copyright (C) 1998-2005 Ivo Timmermans,
4 2000-2014 Guus Sliepen <guus@tinc-vpn.org>
5 2006 Scott Lamb <slamb@slamb.org>
6 2009 Florian Forster <octo@verplant.org>
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.
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.
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.
26 #include "connection.h"
27 #include "control_common.h"
38 /* Needed on Mac OS/X */
40 #define SOL_TCP IPPROTO_TCP
43 int addressfamily = AF_UNSPEC;
45 int seconds_till_retry = 5;
48 int max_connection_burst = 100;
50 listen_socket_t listen_socket[MAXSOCKETS];
55 list_t *outgoing_list = NULL;
59 static void configure_tcp(connection_t *c) {
63 int flags = fcntl(c->socket, F_GETFL);
65 if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
66 logger(DEBUG_ALWAYS, LOG_ERR, "fcntl for %s: %s", c->hostname, strerror(errno));
69 unsigned long arg = 1;
71 if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
72 logger(DEBUG_ALWAYS, LOG_ERR, "ioctlsocket for %s: %s", c->hostname, sockstrerror(sockerrno));
76 #if defined(SOL_TCP) && defined(TCP_NODELAY)
78 setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&option, sizeof option);
81 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
82 option = IPTOS_LOWDELAY;
83 setsockopt(c->socket, SOL_IP, IP_TOS, (void *)&option, sizeof option);
87 static bool bind_to_interface(int sd) {
90 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
93 #endif /* defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) */
95 if(!get_config_string (lookup_config (config_tree, "BindToInterface"), &iface))
98 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
99 memset(&ifr, 0, sizeof(ifr));
100 strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
101 ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
103 status = setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr));
105 logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to interface %s: %s", iface,
106 sockstrerror(sockerrno));
109 #else /* if !defined(SOL_SOCKET) || !defined(SO_BINDTODEVICE) */
110 logger(DEBUG_ALWAYS, LOG_WARNING, "%s not supported on this platform", "BindToInterface");
116 static bool bind_to_address(connection_t *c) {
119 for(int i = 0; i < listen_sockets && listen_socket[i].bindto; i++) {
120 if(listen_socket[i].sa.sa.sa_family != c->address.sa.sa_family)
130 sockaddr_t sa = listen_socket[s].sa;
131 if(sa.sa.sa_family == AF_INET)
133 else if(sa.sa.sa_family == AF_INET6)
134 sa.in6.sin6_port = 0;
136 if(bind(c->socket, &sa.sa, SALEN(sa.sa))) {
137 logger(DEBUG_CONNECTIONS, LOG_WARNING, "Can't bind outgoing socket: %s", sockstrerror(sockerrno));
144 int setup_listen_socket(const sockaddr_t *sa) {
150 nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
153 logger(DEBUG_STATUS, LOG_ERR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
158 fcntl(nfd, F_SETFD, FD_CLOEXEC);
161 /* Optimize TCP settings */
164 setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
166 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
167 if(sa->sa.sa_family == AF_INET6)
168 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
172 (lookup_config(config_tree, "BindToInterface"), &iface)) {
173 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
176 memset(&ifr, 0, sizeof ifr);
177 strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
179 if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof ifr)) {
181 logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to interface %s: %s", iface,
182 sockstrerror(sockerrno));
186 logger(DEBUG_ALWAYS, LOG_WARNING, "%s not supported on this platform", "BindToInterface");
190 if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
192 addrstr = sockaddr2hostname(sa);
193 logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
200 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
207 int setup_vpn_in_socket(const sockaddr_t *sa) {
212 nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
215 logger(DEBUG_ALWAYS, LOG_ERR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
220 fcntl(nfd, F_SETFD, FD_CLOEXEC);
225 int flags = fcntl(nfd, F_GETFL);
227 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
229 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "fcntl",
236 unsigned long arg = 1;
237 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
239 logger(DEBUG_ALWAYS, LOG_ERR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
246 setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
247 setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof option);
249 if(udp_rcvbuf && setsockopt(nfd, SOL_SOCKET, SO_RCVBUF, (void *)&udp_rcvbuf, sizeof(udp_rcvbuf)))
250 logger(DEBUG_ALWAYS, LOG_WARNING, "Can't set UDP SO_RCVBUF to %i: %s", udp_rcvbuf, sockstrerror(sockerrno));
252 if(udp_sndbuf && setsockopt(nfd, SOL_SOCKET, SO_SNDBUF, (void *)&udp_sndbuf, sizeof(udp_sndbuf)))
253 logger(DEBUG_ALWAYS, LOG_WARNING, "Can't set UDP SO_SNDBUF to %i: %s", udp_sndbuf, sockstrerror(sockerrno));
255 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
256 if(sa->sa.sa_family == AF_INET6)
257 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
260 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
261 #define IP_DONTFRAGMENT IP_DONTFRAG
264 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
265 if(myself->options & OPTION_PMTU_DISCOVERY) {
266 option = IP_PMTUDISC_DO;
267 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
269 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
270 if(myself->options & OPTION_PMTU_DISCOVERY) {
272 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
276 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
277 if(myself->options & OPTION_PMTU_DISCOVERY) {
278 option = IPV6_PMTUDISC_DO;
279 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
281 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
282 if(myself->options & OPTION_PMTU_DISCOVERY) {
284 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
288 if (!bind_to_interface(nfd)) {
293 if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
295 addrstr = sockaddr2hostname(sa);
296 logger(DEBUG_ALWAYS, LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
302 } /* int setup_vpn_in_socket */
304 static void retry_outgoing_handler(void *data) {
305 setup_outgoing_connection(data);
308 void retry_outgoing(outgoing_t *outgoing) {
309 outgoing->timeout += 5;
311 if(outgoing->timeout > maxtimeout)
312 outgoing->timeout = maxtimeout;
314 timeout_add(&outgoing->ev, retry_outgoing_handler, outgoing, &(struct timeval){outgoing->timeout, rand() % 100000});
316 logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Trying to re-establish outgoing connection in %d seconds", outgoing->timeout);
319 void finish_connecting(connection_t *c) {
320 logger(DEBUG_CONNECTIONS, LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
322 c->last_ping_time = now.tv_sec;
323 c->status.connecting = false;
328 static void do_outgoing_pipe(connection_t *c, char *command) {
332 if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd)) {
333 logger(DEBUG_ALWAYS, LOG_ERR, "Could not create socketpair: %s", sockstrerror(sockerrno));
340 logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Using proxy %s", command);
351 // Other filedescriptors should be closed automatically by CLOEXEC
356 sockaddr2str(&c->address, &host, &port);
357 setenv("REMOTEADDRESS", host, true);
358 setenv("REMOTEPORT", port, true);
359 setenv("NODE", c->name, true);
360 setenv("NAME", myself->name, true);
362 setenv("NETNAME", netname, true);
364 int result = system(command);
366 logger(DEBUG_ALWAYS, LOG_ERR, "Could not execute %s: %s", command, strerror(errno));
368 logger(DEBUG_ALWAYS, LOG_ERR, "%s exited with non-zero status %d", command, result);
371 logger(DEBUG_ALWAYS, LOG_ERR, "Proxy type exec not supported on this platform!");
376 static void handle_meta_write(connection_t *c) {
377 if(c->outbuf.len <= c->outbuf.offset)
380 ssize_t outlen = send(c->socket, c->outbuf.data + c->outbuf.offset, c->outbuf.len - c->outbuf.offset, 0);
382 if(!sockerrno || sockerrno == EPIPE) {
383 logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection closed by %s (%s)", c->name, c->hostname);
384 } else if(sockwouldblock(sockerrno)) {
385 logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Sending %d bytes to %s (%s) would block", c->outbuf.len - c->outbuf.offset, c->name, c->hostname);
388 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, sockstrerror(sockerrno));
391 terminate_connection(c, c->status.active);
395 buffer_read(&c->outbuf, outlen);
397 io_set(&c->io, IO_READ);
400 static void handle_meta_io(void *data, int flags) {
401 connection_t *c = data;
403 if(c->status.connecting) {
404 /* The event loop does not protect against spurious events. Verify that we are actually connected. */
405 if (connect(c->socket, &c->address.sa, sizeof(c->address)) == 0)
406 logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Error while connecting to %s (%s): redundant connect() unexpectedly succeeded", c->name, c->hostname);
407 else if (!sockisconn(sockerrno)) {
408 if (!sockalready(sockerrno)) {
409 logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Error while checking connection status for %s (%s): %s", c->name, c->hostname, sockstrerror(sockerrno));
410 terminate_connection(c, false);
415 c->status.connecting = false;
418 socklen_t len = sizeof result;
419 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&result, &len);
422 finish_connecting(c);
424 logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Error while connecting to %s (%s): %s", c->name, c->hostname, sockstrerror(result));
425 terminate_connection(c, false);
431 handle_meta_write(c);
433 handle_meta_connection_data(c);
436 bool do_outgoing_connection(outgoing_t *outgoing) {
437 char *address, *port, *space;
438 struct addrinfo *proxyai = NULL;
444 logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not set up a meta connection to %s", outgoing->name);
445 retry_outgoing(outgoing);
449 get_config_string(outgoing->cfg, &address);
451 space = strchr(address, ' ');
453 port = xstrdup(space + 1);
456 if(!get_config_string(lookup_config(outgoing->config_tree, "Port"), &port))
457 port = xstrdup("655");
460 outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
464 outgoing->aip = outgoing->ai;
465 outgoing->cfg = lookup_config_next(outgoing->config_tree, outgoing->cfg);
470 freeaddrinfo(outgoing->ai);
475 connection_t *c = new_connection();
476 c->outgoing = outgoing;
478 memcpy(&c->address, outgoing->aip->ai_addr, outgoing->aip->ai_addrlen);
479 outgoing->aip = outgoing->aip->ai_next;
481 c->hostname = sockaddr2hostname(&c->address);
483 logger(DEBUG_CONNECTIONS, LOG_INFO, "Trying to connect to %s (%s)", outgoing->name, c->hostname);
486 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
488 } else if(proxytype == PROXY_EXEC) {
489 do_outgoing_pipe(c, proxyhost);
491 proxyai = str2addrinfo(proxyhost, proxyport, SOCK_STREAM);
496 logger(DEBUG_CONNECTIONS, LOG_INFO, "Using proxy at %s port %s", proxyhost, proxyport);
497 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
501 if(c->socket == -1) {
502 logger(DEBUG_CONNECTIONS, LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
508 fcntl(c->socket, F_SETFD, FD_CLOEXEC);
511 if(proxytype != PROXY_EXEC) {
512 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
514 if(c->address.sa.sa_family == AF_INET6)
515 setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
518 bind_to_interface(c->socket);
525 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
526 } else if(proxytype == PROXY_EXEC) {
529 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
530 freeaddrinfo(proxyai);
533 if(result == -1 && !sockinprogress(sockerrno)) {
534 logger(DEBUG_CONNECTIONS, LOG_ERR, "Could not connect to %s (%s): %s", outgoing->name, c->hostname, sockstrerror(sockerrno));
540 /* Now that there is a working socket, fill in the rest and register this connection. */
542 c->status.connecting = true;
543 c->name = xstrdup(outgoing->name);
544 c->outcipher = myself->connection->outcipher;
545 c->outdigest = myself->connection->outdigest;
546 c->outmaclength = myself->connection->outmaclength;
547 c->outcompression = myself->connection->outcompression;
548 c->last_ping_time = now.tv_sec;
552 io_add(&c->io, handle_meta_io, c, c->socket, IO_READ|IO_WRITE);
557 // Find edges pointing to this node, and use them to build a list of unique, known addresses.
558 static struct addrinfo *get_known_addresses(node_t *n) {
559 struct addrinfo *ai = NULL;
561 for splay_each(edge_t, e, n->edge_tree) {
566 for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
567 if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
575 struct addrinfo *nai = xzalloc(sizeof *nai);
579 ai->ai_family = e->reverse->address.sa.sa_family;
580 ai->ai_socktype = SOCK_STREAM;
581 ai->ai_protocol = IPPROTO_TCP;
582 ai->ai_addrlen = SALEN(e->reverse->address.sa);
583 ai->ai_addr = xmalloc(ai->ai_addrlen);
584 memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
590 void setup_outgoing_connection(outgoing_t *outgoing) {
591 timeout_del(&outgoing->ev);
593 node_t *n = lookup_node(outgoing->name);
595 if(n && n->connection) {
596 logger(DEBUG_CONNECTIONS, LOG_INFO, "Already connected to %s", outgoing->name);
598 n->connection->outgoing = outgoing;
602 init_configuration(&outgoing->config_tree);
603 read_host_config(outgoing->config_tree, outgoing->name);
604 outgoing->cfg = lookup_config(outgoing->config_tree, "Address");
608 outgoing->aip = outgoing->ai = get_known_addresses(n);
610 logger(DEBUG_ALWAYS, LOG_ERR, "No address known for %s", outgoing->name);
615 do_outgoing_connection(outgoing);
619 accept a new tcp connect and create a
622 void handle_new_meta_connection(void *data, int flags) {
623 listen_socket_t *l = data;
627 socklen_t len = sizeof sa;
629 fd = accept(l->tcp.fd, &sa.sa, &len);
632 logger(DEBUG_ALWAYS, LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
638 // Check if we get many connections from the same host
640 static sockaddr_t prev_sa;
641 static int tarpit = -1;
648 if(!sockaddrcmp_noport(&sa, &prev_sa)) {
649 static int samehost_burst;
650 static int samehost_burst_time;
652 if(now.tv_sec - samehost_burst_time > samehost_burst)
655 samehost_burst -= now.tv_sec - samehost_burst_time;
657 samehost_burst_time = now.tv_sec;
660 if(samehost_burst > max_connection_burst) {
666 memcpy(&prev_sa, &sa, sizeof sa);
668 // Check if we get many connections from different hosts
670 static int connection_burst;
671 static int connection_burst_time;
673 if(now.tv_sec - connection_burst_time > connection_burst)
674 connection_burst = 0;
676 connection_burst -= now.tv_sec - connection_burst_time;
678 connection_burst_time = now.tv_sec;
681 if(connection_burst >= max_connection_burst) {
682 connection_burst = max_connection_burst;
687 // Accept the new connection
689 c = new_connection();
690 c->name = xstrdup("<unknown>");
691 c->outcipher = myself->connection->outcipher;
692 c->outdigest = myself->connection->outdigest;
693 c->outmaclength = myself->connection->outmaclength;
694 c->outcompression = myself->connection->outcompression;
697 c->hostname = sockaddr2hostname(&sa);
699 c->last_ping_time = now.tv_sec;
701 logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection from %s", c->hostname);
703 io_add(&c->io, handle_meta_io, c, c->socket, IO_READ);
709 c->allow_request = ID;
715 accept a new UNIX socket connection
717 void handle_new_unix_connection(void *data, int flags) {
722 socklen_t len = sizeof sa;
724 fd = accept(io->fd, &sa.sa, &len);
727 logger(DEBUG_ALWAYS, LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
733 c = new_connection();
734 c->name = xstrdup("<control>");
736 c->hostname = xstrdup("localhost port unix");
738 c->last_ping_time = now.tv_sec;
740 logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection from %s", c->hostname);
742 io_add(&c->io, handle_meta_io, c, c->socket, IO_READ);
746 c->allow_request = ID;
752 static void free_outgoing(outgoing_t *outgoing) {
753 timeout_del(&outgoing->ev);
756 freeaddrinfo(outgoing->ai);
758 if(outgoing->config_tree)
759 exit_configuration(&outgoing->config_tree);
762 free(outgoing->name);
767 void try_outgoing_connections(void) {
768 /* If there is no outgoing list yet, create one. Otherwise, mark all outgoings as deleted. */
771 outgoing_list = list_alloc((list_action_t)free_outgoing);
773 for list_each(outgoing_t, outgoing, outgoing_list)
774 outgoing->timeout = -1;
777 /* Make sure there is one outgoing_t in the list for each ConnectTo. */
779 for(config_t *cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
781 get_config_string(cfg, &name);
783 if(!check_id(name)) {
784 logger(DEBUG_ALWAYS, LOG_ERR,
785 "Invalid name for outgoing connection in %s line %d",
786 cfg->file, cfg->line);
793 for list_each(outgoing_t, outgoing, outgoing_list) {
794 if(!strcmp(outgoing->name, name)) {
796 outgoing->timeout = 0;
802 outgoing_t *outgoing = xzalloc(sizeof *outgoing);
803 outgoing->name = name;
804 list_insert_tail(outgoing_list, outgoing);
805 setup_outgoing_connection(outgoing);
809 /* Terminate any connections whose outgoing_t is to be deleted. */
811 for list_each(connection_t, c, connection_list) {
812 if(c->outgoing && c->outgoing->timeout == -1) {
814 logger(DEBUG_CONNECTIONS, LOG_INFO, "No more outgoing connection to %s", c->name);
815 terminate_connection(c, c->status.active);
819 /* Delete outgoing_ts for which there is no ConnectTo. */
821 for list_each(outgoing_t, outgoing, outgoing_list)
822 if(outgoing->timeout == -1)
823 list_delete_node(outgoing_list, node);