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));
56 unsigned long arg = 1;
58 if(ioctlsocket(c->socket, FIONBIO, &arg) != 0)
59 logger(c->mesh, MESHLINK_ERROR, "ioctlsocket for %s: %s", c->hostname, sockstrerror(sockerrno));
62 #if defined(SOL_TCP) && defined(TCP_NODELAY)
64 setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&nodelay, sizeof nodelay);
67 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
68 int lowdelay = IPTOS_LOWDELAY;
69 setsockopt(c->socket, SOL_IP, IP_TOS, (void *)&lowdelay, sizeof lowdelay);
73 static bool bind_to_address(meshlink_handle_t *mesh, connection_t *c) {
76 for(int i = 0; i < mesh->listen_sockets && mesh->listen_socket[i].bindto; i++) {
77 if(mesh->listen_socket[i].sa.sa.sa_family != c->address.sa.sa_family)
87 sockaddr_t sa = mesh->listen_socket[s].sa;
88 if(sa.sa.sa_family == AF_INET)
90 else if(sa.sa.sa_family == AF_INET6)
93 if(bind(c->socket, &sa.sa, SALEN(sa.sa))) {
94 logger(mesh, MESHLINK_WARNING, "Can't bind outgoing socket: %s", strerror(errno));
101 int setup_listen_socket(const sockaddr_t *sa) {
106 nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
109 logger(NULL, MESHLINK_ERROR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
114 fcntl(nfd, F_SETFD, FD_CLOEXEC);
117 /* Optimize TCP settings */
120 setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
122 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
123 if(sa->sa.sa_family == AF_INET6)
124 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
127 if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
129 addrstr = sockaddr2hostname(sa);
130 logger(NULL, MESHLINK_ERROR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
137 logger(NULL, MESHLINK_ERROR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
144 int setup_vpn_in_socket(meshlink_handle_t *mesh, const sockaddr_t *sa) {
149 nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
152 logger(mesh, MESHLINK_ERROR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
157 fcntl(nfd, F_SETFD, FD_CLOEXEC);
162 int flags = fcntl(nfd, F_GETFL);
164 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
166 logger(mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "fcntl",
173 unsigned long arg = 1;
174 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
176 logger(mesh, MESHLINK_ERROR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
183 setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
184 setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof option);
186 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
187 if(sa->sa.sa_family == AF_INET6)
188 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
191 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
192 #define IP_DONTFRAGMENT IP_DONTFRAG
195 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
196 if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
197 option = IP_PMTUDISC_DO;
198 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
200 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
201 if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
203 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
206 #warning No way to disable IPv4 fragmentation
209 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
210 if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
211 option = IPV6_PMTUDISC_DO;
212 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
214 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
215 if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
217 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
220 #warning No way to disable IPv6 fragmentation
223 if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
225 addrstr = sockaddr2hostname(sa);
226 logger(mesh, MESHLINK_ERROR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
232 } /* int setup_vpn_in_socket */
234 static void retry_outgoing_handler(event_loop_t *loop, void *data) {
235 meshlink_handle_t *mesh = loop->data;
236 outgoing_t *outgoing = data;
237 setup_outgoing_connection(mesh, outgoing);
240 void retry_outgoing(meshlink_handle_t *mesh, outgoing_t *outgoing) {
241 outgoing->timeout += 5;
243 if(outgoing->timeout > mesh->maxtimeout)
244 outgoing->timeout = mesh->maxtimeout;
246 timeout_add(&mesh->loop, &outgoing->ev, retry_outgoing_handler, outgoing, &(struct timeval) {
247 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));
322 terminate_connection(mesh, c, c->status.active);
326 buffer_read(&c->outbuf, outlen);
328 io_set(&mesh->loop, &c->io, IO_READ);
331 static void handle_meta_io(event_loop_t *loop, void *data, int flags) {
332 meshlink_handle_t *mesh = loop->data;
333 connection_t *c = data;
335 if(c->status.connecting) {
336 c->status.connecting = false;
339 socklen_t len = sizeof result;
340 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&result, &len);
343 finish_connecting(mesh, c);
345 logger(mesh, MESHLINK_DEBUG, "Error while connecting to %s (%s): %s", c->name, c->hostname, sockstrerror(result));
346 terminate_connection(mesh, c, false);
352 handle_meta_write(mesh, c);
354 handle_meta_connection_data(mesh, c);
357 // Find edges pointing to this node, and use them to build a list of unique, known addresses.
358 static struct addrinfo *get_known_addresses(node_t *n) {
359 struct addrinfo *ai = NULL;
361 for splay_each(edge_t, e, n->edge_tree) {
366 for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
367 if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
375 // Create a new struct addrinfo, and put it at the head of the list.
376 struct addrinfo *nai = xzalloc(sizeof *nai + SALEN(e->reverse->address.sa));
380 ai->ai_family = e->reverse->address.sa.sa_family;
381 ai->ai_socktype = SOCK_STREAM;
382 ai->ai_protocol = IPPROTO_TCP;
383 ai->ai_addrlen = SALEN(e->reverse->address.sa);
384 ai->ai_addr = (struct sockaddr *)(nai + 1);
385 memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
391 // Free struct addrinfo list from get_known_addresses().
392 static void free_known_addresses(struct addrinfo *ai) {
393 for(struct addrinfo *aip = ai, *next; aip; aip = next) {
399 bool do_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
400 char *address, *port, *space;
401 struct addrinfo *proxyai = NULL;
405 if(!outgoing->ai && !outgoing->nai) {
407 logger(mesh, MESHLINK_ERROR, "Could not set up a meta connection to %s", outgoing->name);
408 retry_outgoing(mesh, outgoing);
412 get_config_string(outgoing->cfg, &address);
414 space = strchr(address, ' ');
416 port = xstrdup(space + 1);
419 // TODO: Only allow Address statements?
420 if(!get_config_string(lookup_config(outgoing->config_tree, "Port"), &port)) {
421 logger(mesh, MESHLINK_ERROR, "No Port known for %s", outgoing->name);
422 retry_outgoing(mesh, outgoing);
427 outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
431 outgoing->aip = outgoing->ai;
432 outgoing->cfg = lookup_config_next(outgoing->config_tree, outgoing->cfg);
437 freeaddrinfo(outgoing->ai);
441 free_known_addresses(outgoing->nai);
442 outgoing->nai = NULL;
447 connection_t *c = new_connection();
448 c->outgoing = outgoing;
450 memcpy(&c->address, outgoing->aip->ai_addr, outgoing->aip->ai_addrlen);
451 outgoing->aip = outgoing->aip->ai_next;
453 c->hostname = sockaddr2hostname(&c->address);
455 logger(mesh, MESHLINK_INFO, "Trying to connect to %s (%s)", outgoing->name, c->hostname);
457 if(!mesh->proxytype) {
458 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
460 } else if(mesh->proxytype == PROXY_EXEC)
461 do_outgoing_pipe(mesh, c, mesh->proxyhost);
463 proxyai = str2addrinfo(mesh->proxyhost, mesh->proxyport, SOCK_STREAM);
468 logger(mesh, MESHLINK_INFO, "Using proxy at %s port %s", mesh->proxyhost, mesh->proxyport);
469 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
473 if(c->socket == -1) {
474 logger(mesh, MESHLINK_ERROR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
480 fcntl(c->socket, F_SETFD, FD_CLOEXEC);
483 if(mesh->proxytype != PROXY_EXEC) {
484 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
486 if(c->address.sa.sa_family == AF_INET6)
487 setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
490 bind_to_address(mesh, c);
496 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
497 else if(mesh->proxytype == PROXY_EXEC)
500 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
501 freeaddrinfo(proxyai);
504 if(result == -1 && !sockinprogress(sockerrno)) {
505 logger(mesh, MESHLINK_ERROR, "Could not connect to %s (%s): %s", outgoing->name, c->hostname, sockstrerror(sockerrno));
511 /* Now that there is a working socket, fill in the rest and register this connection. */
513 c->status.connecting = true;
514 c->name = xstrdup(outgoing->name);
515 c->outcompression = mesh->self->connection->outcompression;
516 c->last_ping_time = mesh->loop.now.tv_sec;
518 connection_add(mesh, c);
520 io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ|IO_WRITE);
525 void setup_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
526 bool blacklisted = false;
527 timeout_del(&mesh->loop, &outgoing->ev);
529 node_t *n = lookup_node(mesh, outgoing->name);
531 if(n && n->connection) {
532 logger(mesh, MESHLINK_INFO, "Already connected to %s", outgoing->name);
534 n->connection->outgoing = outgoing;
538 exit_configuration(&outgoing->config_tree); // discard old configuration if present
539 init_configuration(&outgoing->config_tree);
540 read_host_config(mesh, outgoing->config_tree, outgoing->name);
541 outgoing->cfg = lookup_config(outgoing->config_tree, "Address");
543 get_config_bool(lookup_config(outgoing->config_tree, "blacklisted"), &blacklisted);
544 if(blacklisted) return;
548 outgoing->aip = outgoing->nai = get_known_addresses(n);
550 logger(mesh, MESHLINK_ERROR, "No address known for %s", outgoing->name);
555 do_outgoing_connection(mesh, outgoing);
559 accept a new tcp connect and create a
562 void handle_new_meta_connection(event_loop_t *loop, void *data, int flags) {
563 meshlink_handle_t *mesh = loop->data;
564 listen_socket_t *l = data;
568 socklen_t len = sizeof sa;
570 fd = accept(l->tcp.fd, &sa.sa, &len);
573 if(errno == EINVAL) { // TODO: check if Windows agrees
574 event_loop_stop(loop);
578 logger(mesh, MESHLINK_ERROR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
584 // Check if we get many connections from the same host
586 static sockaddr_t prev_sa;
587 static int tarpit = -1;
594 if(!sockaddrcmp_noport(&sa, &prev_sa)) {
595 static int samehost_burst;
596 static int samehost_burst_time;
598 if(mesh->loop.now.tv_sec - samehost_burst_time > samehost_burst)
601 samehost_burst -= mesh->loop.now.tv_sec - samehost_burst_time;
603 samehost_burst_time = mesh->loop.now.tv_sec;
606 if(samehost_burst > max_connection_burst) {
612 memcpy(&prev_sa, &sa, sizeof sa);
614 // Check if we get many connections from different hosts
616 static int connection_burst;
617 static int connection_burst_time;
619 if(mesh->loop.now.tv_sec - connection_burst_time > connection_burst)
620 connection_burst = 0;
622 connection_burst -= mesh->loop.now.tv_sec - connection_burst_time;
624 connection_burst_time = mesh->loop.now.tv_sec;
627 if(connection_burst >= max_connection_burst) {
628 connection_burst = max_connection_burst;
633 // Accept the new connection
635 c = new_connection();
636 c->name = xstrdup("<unknown>");
637 c->outcompression = mesh->self->connection->outcompression;
640 c->hostname = sockaddr2hostname(&sa);
642 c->last_ping_time = mesh->loop.now.tv_sec;
644 logger(mesh, MESHLINK_INFO, "Connection from %s", c->hostname);
646 io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ);
650 connection_add(mesh, c);
652 c->allow_request = ID;
656 static void free_outgoing(outgoing_t *outgoing) {
657 meshlink_handle_t *mesh = outgoing->mesh;
659 timeout_del(&mesh->loop, &outgoing->ev);
662 freeaddrinfo(outgoing->ai);
665 free_known_addresses(outgoing->nai);
667 if(outgoing->config_tree)
668 exit_configuration(&outgoing->config_tree);
671 free(outgoing->name);
676 void try_outgoing_connections(meshlink_handle_t *mesh) {
677 /* If there is no outgoing list yet, create one. Otherwise, mark all outgoings as deleted. */
680 mesh->outgoings = list_alloc((list_action_t)free_outgoing);
682 for list_each(outgoing_t, outgoing, mesh->outgoings)
683 outgoing->timeout = -1;
686 /* Make sure there is one outgoing_t in the list for each ConnectTo. */
688 // TODO: Drop support for ConnectTo since AutoConnect is now always on?
689 for(config_t *cfg = lookup_config(mesh->config, "ConnectTo"); cfg; cfg = lookup_config_next(mesh->config, cfg)) {
691 get_config_string(cfg, &name);
693 if(!check_id(name)) {
694 logger(mesh, MESHLINK_ERROR,
695 "Invalid name for outgoing connection in %s line %d",
696 cfg->file, cfg->line);
703 for list_each(outgoing_t, outgoing, mesh->outgoings) {
704 if(!strcmp(outgoing->name, name)) {
706 outgoing->timeout = 0;
712 outgoing_t *outgoing = xzalloc(sizeof *outgoing);
713 outgoing->mesh = mesh;
714 outgoing->name = name;
715 list_insert_tail(mesh->outgoings, outgoing);
716 setup_outgoing_connection(mesh, outgoing);
720 /* Terminate any connections whose outgoing_t is to be deleted. */
722 for list_each(connection_t, c, mesh->connections) {
723 if(c->outgoing && c->outgoing->timeout == -1) {
725 logger(mesh, MESHLINK_INFO, "No more outgoing connection to %s", c->name);
726 terminate_connection(mesh, c, c->status.active);
730 /* Delete outgoing_ts for which there is no ConnectTo. */
732 for list_each(outgoing_t, outgoing, mesh->outgoings)
733 if(outgoing->timeout == -1)
734 list_delete_node(mesh->outgoings, node);