2 net_socket.c -- Handle various kinds of sockets.
3 Copyright (C) 2014 Guus Sliepen <guus@meshlink.io>
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.
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.
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.
23 #include "connection.h"
26 #include "meshlink_internal.h"
34 /* Needed on Mac OS/X */
36 #define SOL_TCP IPPROTO_TCP
40 #define MSG_NOSIGNAL 0
43 int addressfamily = AF_UNSPEC;
44 int seconds_till_retry = 5;
45 int max_connection_burst = 100;
49 static void configure_tcp(connection_t *c) {
51 int flags = fcntl(c->socket, F_GETFL);
53 if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
54 logger(c->mesh, MESHLINK_ERROR, "fcntl for %s: %s", c->hostname, strerror(errno));
57 unsigned long arg = 1;
59 if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
60 logger(c->mesh, MESHLINK_ERROR, "ioctlsocket for %s: %s", c->hostname, sockstrerror(sockerrno));
64 #if defined(SOL_TCP) && defined(TCP_NODELAY)
66 setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&nodelay, sizeof nodelay);
69 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
70 int lowdelay = IPTOS_LOWDELAY;
71 setsockopt(c->socket, SOL_IP, IP_TOS, (void *)&lowdelay, sizeof lowdelay);
75 static bool bind_to_address(meshlink_handle_t *mesh, connection_t *c) {
78 for(int i = 0; i < mesh->listen_sockets && mesh->listen_socket[i].bindto; i++) {
79 if(mesh->listen_socket[i].sa.sa.sa_family != c->address.sa.sa_family)
89 sockaddr_t sa = mesh->listen_socket[s].sa;
90 if(sa.sa.sa_family == AF_INET)
92 else if(sa.sa.sa_family == AF_INET6)
95 if(bind(c->socket, &sa.sa, SALEN(sa.sa))) {
96 logger(mesh, MESHLINK_WARNING, "Can't bind outgoing socket: %s", strerror(errno));
103 int setup_listen_socket(const sockaddr_t *sa) {
108 nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
111 logger(NULL, MESHLINK_ERROR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
116 fcntl(nfd, F_SETFD, FD_CLOEXEC);
119 /* Optimize TCP settings */
122 setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
124 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
125 if(sa->sa.sa_family == AF_INET6)
126 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
129 if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
131 addrstr = sockaddr2hostname(sa);
132 logger(NULL, MESHLINK_ERROR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
139 logger(NULL, MESHLINK_ERROR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
146 int setup_vpn_in_socket(meshlink_handle_t *mesh, const sockaddr_t *sa) {
151 nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
154 logger(mesh, MESHLINK_ERROR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
159 fcntl(nfd, F_SETFD, FD_CLOEXEC);
164 int flags = fcntl(nfd, F_GETFL);
166 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
168 logger(mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "fcntl",
175 unsigned long arg = 1;
176 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
178 logger(mesh, MESHLINK_ERROR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
185 setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
186 setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof option);
188 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
189 if(sa->sa.sa_family == AF_INET6)
190 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
193 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
194 #define IP_DONTFRAGMENT IP_DONTFRAG
197 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
198 if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
199 option = IP_PMTUDISC_DO;
200 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
202 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
203 if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
205 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
208 #warning No way to disable IPv4 fragmentation
211 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
212 if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
213 option = IPV6_PMTUDISC_DO;
214 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
216 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
217 if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
219 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
222 #warning No way to disable IPv6 fragmentation
225 if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
227 addrstr = sockaddr2hostname(sa);
228 logger(mesh, MESHLINK_ERROR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
234 } /* int setup_vpn_in_socket */
236 static void retry_outgoing_handler(event_loop_t *loop, void *data) {
237 meshlink_handle_t *mesh = loop->data;
238 outgoing_t *outgoing = data;
239 setup_outgoing_connection(mesh, outgoing);
242 void retry_outgoing(meshlink_handle_t *mesh, outgoing_t *outgoing) {
243 outgoing->timeout += 5;
245 if(outgoing->timeout > mesh->maxtimeout)
246 outgoing->timeout = mesh->maxtimeout;
248 timeout_add(&mesh->loop, &outgoing->ev, retry_outgoing_handler, outgoing, &(struct timeval){outgoing->timeout, rand() % 100000});
250 logger(mesh, MESHLINK_INFO, "Trying to re-establish outgoing connection in %d seconds", outgoing->timeout);
253 void finish_connecting(meshlink_handle_t *mesh, connection_t *c) {
254 logger(mesh, MESHLINK_INFO, "Connected to %s (%s)", c->name, c->hostname);
256 c->last_ping_time = mesh->loop.now.tv_sec;
257 c->status.connecting = false;
262 static void do_outgoing_pipe(meshlink_handle_t *mesh, connection_t *c, char *command) {
266 if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd)) {
267 logger(mesh, MESHLINK_ERROR, "Could not create socketpair: %s", strerror(errno));
274 logger(mesh, MESHLINK_DEBUG, "Using proxy %s", command);
285 // Other filedescriptors should be closed automatically by CLOEXEC
290 sockaddr2str(&c->address, &host, &port);
291 setenv("REMOTEADDRESS", host, true);
292 setenv("REMOTEPORT", port, true);
293 setenv("NODE", c->name, true);
294 setenv("NAME", mesh->self->name, true);
296 int result = system(command);
298 logger(mesh, MESHLINK_ERROR, "Could not execute %s: %s", command, strerror(errno));
300 logger(mesh, MESHLINK_ERROR, "%s exited with non-zero status %d", command, result);
303 logger(mesh, MESHLINK_ERROR, "Proxy type exec not supported on this platform!");
308 static void handle_meta_write(meshlink_handle_t *mesh, connection_t *c) {
309 if(c->outbuf.len <= c->outbuf.offset)
312 ssize_t outlen = send(c->socket, c->outbuf.data + c->outbuf.offset, c->outbuf.len - c->outbuf.offset, MSG_NOSIGNAL);
314 if(!errno || errno == EPIPE) {
315 logger(mesh, MESHLINK_INFO, "Connection closed by %s (%s)", c->name, c->hostname);
316 } else if(sockwouldblock(sockerrno)) {
317 logger(mesh, MESHLINK_DEBUG, "Sending %d bytes to %s (%s) would block", c->outbuf.len - c->outbuf.offset, c->name, c->hostname);
320 logger(mesh, MESHLINK_ERROR, "Could not send %d bytes of data to %s (%s): %s", c->outbuf.len - c->outbuf.offset, c->name, c->hostname, strerror(errno));
323 terminate_connection(mesh, c, c->status.active);
327 buffer_read(&c->outbuf, outlen);
329 io_set(&mesh->loop, &c->io, IO_READ);
332 static void handle_meta_io(event_loop_t *loop, void *data, int flags) {
333 meshlink_handle_t *mesh = loop->data;
334 connection_t *c = data;
336 if(c->status.connecting) {
337 c->status.connecting = false;
340 socklen_t len = sizeof result;
341 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&result, &len);
344 finish_connecting(mesh, c);
346 logger(mesh, MESHLINK_DEBUG, "Error while connecting to %s (%s): %s", c->name, c->hostname, sockstrerror(result));
347 terminate_connection(mesh, c, false);
353 handle_meta_write(mesh, c);
355 handle_meta_connection_data(mesh, c);
358 bool do_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
359 char *address, *port, *space;
360 struct addrinfo *proxyai = NULL;
366 logger(mesh, MESHLINK_ERROR, "Could not set up a meta connection to %s", outgoing->name);
367 retry_outgoing(mesh, outgoing);
371 get_config_string(outgoing->cfg, &address);
373 space = strchr(address, ' ');
375 port = xstrdup(space + 1);
378 // TODO: Only allow Address statements?
379 if(!get_config_string(lookup_config(outgoing->config_tree, "Port"), &port)) {
380 logger(mesh, MESHLINK_ERROR, "No Port known for %s", outgoing->name);
381 retry_outgoing(mesh, outgoing);
386 outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
390 outgoing->aip = outgoing->ai;
391 outgoing->cfg = lookup_config_next(outgoing->config_tree, outgoing->cfg);
396 freeaddrinfo(outgoing->ai);
401 connection_t *c = new_connection();
402 c->outgoing = outgoing;
404 memcpy(&c->address, outgoing->aip->ai_addr, outgoing->aip->ai_addrlen);
405 outgoing->aip = outgoing->aip->ai_next;
407 c->hostname = sockaddr2hostname(&c->address);
409 logger(mesh, MESHLINK_INFO, "Trying to connect to %s (%s)", outgoing->name, c->hostname);
411 if(!mesh->proxytype) {
412 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
414 } else if(mesh->proxytype == PROXY_EXEC) {
415 do_outgoing_pipe(mesh, c, mesh->proxyhost);
417 proxyai = str2addrinfo(mesh->proxyhost, mesh->proxyport, SOCK_STREAM);
422 logger(mesh, MESHLINK_INFO, "Using proxy at %s port %s", mesh->proxyhost, mesh->proxyport);
423 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
427 if(c->socket == -1) {
428 logger(mesh, MESHLINK_ERROR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
434 fcntl(c->socket, F_SETFD, FD_CLOEXEC);
437 if(mesh->proxytype != PROXY_EXEC) {
438 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
440 if(c->address.sa.sa_family == AF_INET6)
441 setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
444 bind_to_address(mesh, c);
449 if(!mesh->proxytype) {
450 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
451 } else if(mesh->proxytype == PROXY_EXEC) {
454 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
455 freeaddrinfo(proxyai);
458 if(result == -1 && !sockinprogress(sockerrno)) {
459 logger(mesh, MESHLINK_ERROR, "Could not connect to %s (%s): %s", outgoing->name, c->hostname, sockstrerror(sockerrno));
465 /* Now that there is a working socket, fill in the rest and register this connection. */
467 c->status.connecting = true;
468 c->name = xstrdup(outgoing->name);
469 c->outcompression = mesh->self->connection->outcompression;
470 c->last_ping_time = mesh->loop.now.tv_sec;
472 connection_add(mesh, c);
474 io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ|IO_WRITE);
479 // Find edges pointing to this node, and use them to build a list of unique, known addresses.
480 static struct addrinfo *get_known_addresses(node_t *n) {
481 struct addrinfo *ai = NULL;
483 for splay_each(edge_t, e, n->edge_tree) {
488 for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
489 if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
497 struct addrinfo *nai = xzalloc(sizeof *nai);
501 ai->ai_family = e->reverse->address.sa.sa_family;
502 ai->ai_socktype = SOCK_STREAM;
503 ai->ai_protocol = IPPROTO_TCP;
504 ai->ai_addrlen = SALEN(e->reverse->address.sa);
505 ai->ai_addr = xmalloc(ai->ai_addrlen);
506 memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
512 void setup_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
513 bool blacklisted = false;
514 timeout_del(&mesh->loop, &outgoing->ev);
516 node_t *n = lookup_node(mesh, outgoing->name);
518 if(n && n->connection) {
519 logger(mesh, MESHLINK_INFO, "Already connected to %s", outgoing->name);
521 n->connection->outgoing = outgoing;
525 init_configuration(&outgoing->config_tree);
526 read_host_config(mesh, outgoing->config_tree, outgoing->name);
527 outgoing->cfg = lookup_config(outgoing->config_tree, "Address");
529 get_config_bool(lookup_config(outgoing->config_tree, "blacklisted"), &blacklisted);
530 if (blacklisted) return;
534 outgoing->aip = outgoing->ai = get_known_addresses(n);
536 logger(mesh, MESHLINK_ERROR, "No address known for %s", outgoing->name);
541 do_outgoing_connection(mesh, outgoing);
545 accept a new tcp connect and create a
548 void handle_new_meta_connection(event_loop_t *loop, void *data, int flags) {
549 meshlink_handle_t *mesh = loop->data;
550 listen_socket_t *l = data;
554 socklen_t len = sizeof sa;
556 fd = accept(l->tcp.fd, &sa.sa, &len);
559 if(errno == EINVAL) { // TODO: check if Windows agrees
560 event_loop_stop(loop);
564 logger(mesh, MESHLINK_ERROR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
570 // Check if we get many connections from the same host
572 static sockaddr_t prev_sa;
573 static int tarpit = -1;
580 if(!sockaddrcmp_noport(&sa, &prev_sa)) {
581 static int samehost_burst;
582 static int samehost_burst_time;
584 if(mesh->loop.now.tv_sec - samehost_burst_time > samehost_burst)
587 samehost_burst -= mesh->loop.now.tv_sec - samehost_burst_time;
589 samehost_burst_time = mesh->loop.now.tv_sec;
592 if(samehost_burst > max_connection_burst) {
598 memcpy(&prev_sa, &sa, sizeof sa);
600 // Check if we get many connections from different hosts
602 static int connection_burst;
603 static int connection_burst_time;
605 if(mesh->loop.now.tv_sec - connection_burst_time > connection_burst)
606 connection_burst = 0;
608 connection_burst -= mesh->loop.now.tv_sec - connection_burst_time;
610 connection_burst_time = mesh->loop.now.tv_sec;
613 if(connection_burst >= max_connection_burst) {
614 connection_burst = max_connection_burst;
619 // Accept the new connection
621 c = new_connection();
622 c->name = xstrdup("<unknown>");
623 c->outcompression = mesh->self->connection->outcompression;
626 c->hostname = sockaddr2hostname(&sa);
628 c->last_ping_time = mesh->loop.now.tv_sec;
630 logger(mesh, MESHLINK_INFO, "Connection from %s", c->hostname);
632 io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ);
636 connection_add(mesh, c);
638 c->allow_request = ID;
642 static void free_outgoing(outgoing_t *outgoing) {
643 meshlink_handle_t *mesh = outgoing->mesh;
645 timeout_del(&mesh->loop, &outgoing->ev);
648 freeaddrinfo(outgoing->ai);
650 if(outgoing->config_tree)
651 exit_configuration(&outgoing->config_tree);
654 free(outgoing->name);
659 void try_outgoing_connections(meshlink_handle_t *mesh) {
660 /* If there is no outgoing list yet, create one. Otherwise, mark all outgoings as deleted. */
662 if(!mesh->outgoings) {
663 mesh->outgoings = list_alloc((list_action_t)free_outgoing);
665 for list_each(outgoing_t, outgoing, mesh->outgoings)
666 outgoing->timeout = -1;
669 /* Make sure there is one outgoing_t in the list for each ConnectTo. */
671 // TODO: Drop support for ConnectTo since AutoConnect is now always on?
672 for(config_t *cfg = lookup_config(mesh->config, "ConnectTo"); cfg; cfg = lookup_config_next(mesh->config, cfg)) {
674 get_config_string(cfg, &name);
676 if(!check_id(name)) {
677 logger(mesh, MESHLINK_ERROR,
678 "Invalid name for outgoing connection in %s line %d",
679 cfg->file, cfg->line);
686 for list_each(outgoing_t, outgoing, mesh->outgoings) {
687 if(!strcmp(outgoing->name, name)) {
689 outgoing->timeout = 0;
695 outgoing_t *outgoing = xzalloc(sizeof *outgoing);
696 outgoing->mesh = mesh;
697 outgoing->name = name;
698 list_insert_tail(mesh->outgoings, outgoing);
699 setup_outgoing_connection(mesh, outgoing);
703 /* Terminate any connections whose outgoing_t is to be deleted. */
705 for list_each(connection_t, c, mesh->connections) {
706 if(c->outgoing && c->outgoing->timeout == -1) {
708 logger(mesh, MESHLINK_INFO, "No more outgoing connection to %s", c->name);
709 terminate_connection(mesh, c, c->status.active);
713 /* Delete outgoing_ts for which there is no ConnectTo. */
715 for list_each(outgoing_t, outgoing, mesh->outgoings)
716 if(outgoing->timeout == -1)
717 list_delete_node(mesh->outgoings, node);