2 net_socket.c -- Handle various kinds of sockets.
3 Copyright (C) 2014-2017 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, "System call `%s' failed: %s", "fcntl", strerror(errno));
58 unsigned long arg = 1;
60 if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
61 logger(c->mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
66 #if defined(SOL_TCP) && defined(TCP_NODELAY)
68 setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&nodelay, sizeof(nodelay));
71 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
72 int lowdelay = IPTOS_LOWDELAY;
73 setsockopt(c->socket, SOL_IP, IP_TOS, (void *)&lowdelay, sizeof(lowdelay));
77 static bool bind_to_address(meshlink_handle_t *mesh, connection_t *c) {
80 for(int i = 0; i < mesh->listen_sockets && mesh->listen_socket[i].bindto; i++) {
81 if(mesh->listen_socket[i].sa.sa.sa_family != c->address.sa.sa_family) {
96 sockaddr_t sa = mesh->listen_socket[s].sa;
98 if(sa.sa.sa_family == AF_INET) {
100 } else if(sa.sa.sa_family == AF_INET6) {
101 sa.in6.sin6_port = 0;
104 if(bind(c->socket, &sa.sa, SALEN(sa.sa))) {
105 logger(mesh, MESHLINK_WARNING, "Can't bind outgoing socket: %s", strerror(errno));
112 int setup_listen_socket(const sockaddr_t *sa) {
117 nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
120 logger(NULL, MESHLINK_ERROR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
125 fcntl(nfd, F_SETFD, FD_CLOEXEC);
128 /* Optimize TCP settings */
131 setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
133 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
135 if(sa->sa.sa_family == AF_INET6) {
136 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
141 if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
143 addrstr = sockaddr2hostname(sa);
144 logger(NULL, MESHLINK_ERROR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
151 logger(NULL, MESHLINK_ERROR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
158 int setup_vpn_in_socket(meshlink_handle_t *mesh, const sockaddr_t *sa) {
163 nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
166 logger(mesh, MESHLINK_ERROR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
171 fcntl(nfd, F_SETFD, FD_CLOEXEC);
176 int flags = fcntl(nfd, F_GETFL);
178 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
180 logger(mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "fcntl",
187 unsigned long arg = 1;
189 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
191 logger(mesh, MESHLINK_ERROR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
198 setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
199 setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof(option));
201 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
203 if(sa->sa.sa_family == AF_INET6) {
204 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
209 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
210 #define IP_DONTFRAGMENT IP_DONTFRAG
213 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
215 if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
216 option = IP_PMTUDISC_DO;
217 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
220 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
222 if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
224 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
228 #warning No way to disable IPv4 fragmentation
231 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
233 if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
234 option = IPV6_PMTUDISC_DO;
235 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
238 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
240 if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
242 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
246 #warning No way to disable IPv6 fragmentation
249 if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
251 addrstr = sockaddr2hostname(sa);
252 logger(mesh, MESHLINK_ERROR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
258 } /* int setup_vpn_in_socket */
260 static void retry_outgoing_handler(event_loop_t *loop, void *data) {
261 meshlink_handle_t *mesh = loop->data;
262 outgoing_t *outgoing = data;
263 setup_outgoing_connection(mesh, outgoing);
266 void retry_outgoing(meshlink_handle_t *mesh, outgoing_t *outgoing) {
267 outgoing->timeout += 5;
269 if(outgoing->timeout > mesh->maxtimeout) {
270 outgoing->timeout = mesh->maxtimeout;
273 timeout_add(&mesh->loop, &outgoing->ev, retry_outgoing_handler, outgoing, &(struct timeval) {
274 outgoing->timeout, rand() % 100000
277 logger(mesh, MESHLINK_INFO, "Trying to re-establish outgoing connection in %d seconds", outgoing->timeout);
280 void finish_connecting(meshlink_handle_t *mesh, connection_t *c) {
281 logger(mesh, MESHLINK_INFO, "Connected to %s", c->name);
283 c->last_ping_time = mesh->loop.now.tv_sec;
284 c->status.connecting = false;
289 static void do_outgoing_pipe(meshlink_handle_t *mesh, connection_t *c, char *command) {
293 if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd)) {
294 logger(mesh, MESHLINK_ERROR, "Could not create socketpair: %s", strerror(errno));
301 logger(mesh, MESHLINK_DEBUG, "Using proxy %s", command);
312 // Other filedescriptors should be closed automatically by CLOEXEC
317 sockaddr2str(&c->address, &host, &port);
318 setenv("REMOTEADDRESS", host, true);
319 setenv("REMOTEPORT", port, true);
320 setenv("NODE", c->name, true);
321 setenv("NAME", mesh->self->name, true);
323 int result = system(command);
326 logger(mesh, MESHLINK_ERROR, "Could not execute %s: %s", command, strerror(errno));
328 logger(mesh, MESHLINK_ERROR, "%s exited with non-zero status %d", command, result);
333 logger(mesh, MESHLINK_ERROR, "Proxy type exec not supported on this platform!");
338 static void handle_meta_write(meshlink_handle_t *mesh, connection_t *c) {
339 if(c->outbuf.len <= c->outbuf.offset) {
343 ssize_t outlen = send(c->socket, c->outbuf.data + c->outbuf.offset, c->outbuf.len - c->outbuf.offset, MSG_NOSIGNAL);
346 if(!errno || errno == EPIPE) {
347 logger(mesh, MESHLINK_INFO, "Connection closed by %s", c->name);
348 } else if(sockwouldblock(sockerrno)) {
349 logger(mesh, MESHLINK_DEBUG, "Sending %lu bytes to %s would block", (unsigned long)(c->outbuf.len - c->outbuf.offset), c->name);
352 logger(mesh, MESHLINK_ERROR, "Could not send %lu bytes of data to %s: %s", (unsigned long)(c->outbuf.len - c->outbuf.offset), c->name, strerror(errno));
355 terminate_connection(mesh, c, c->status.active);
359 buffer_read(&c->outbuf, outlen);
362 io_set(&mesh->loop, &c->io, IO_READ);
366 static void handle_meta_io(event_loop_t *loop, void *data, int flags) {
367 meshlink_handle_t *mesh = loop->data;
368 connection_t *c = data;
370 if(c->status.connecting) {
371 c->status.connecting = false;
374 socklen_t len = sizeof(result);
375 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&result, &len);
378 finish_connecting(mesh, c);
380 logger(mesh, MESHLINK_DEBUG, "Error while connecting to %s: %s", c->name, sockstrerror(result));
381 terminate_connection(mesh, c, false);
386 if(flags & IO_WRITE) {
387 handle_meta_write(mesh, c);
389 handle_meta_connection_data(mesh, c);
393 // Find edges pointing to this node, and use them to build a list of unique, known addresses.
394 static struct addrinfo *get_known_addresses(node_t *n) {
395 struct addrinfo *ai = NULL;
397 for splay_each(edge_t, e, n->edge_tree) {
404 for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
405 if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
415 // Create a new struct addrinfo, and put it at the head of the list.
416 struct addrinfo *nai = xzalloc(sizeof(*nai) + SALEN(e->reverse->address.sa));
420 ai->ai_family = e->reverse->address.sa.sa_family;
421 ai->ai_socktype = SOCK_STREAM;
422 ai->ai_protocol = IPPROTO_TCP;
423 ai->ai_addrlen = SALEN(e->reverse->address.sa);
424 ai->ai_addr = (struct sockaddr *)(nai + 1);
425 memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
431 // Free struct addrinfo list from get_known_addresses().
432 static void free_known_addresses(struct addrinfo *ai) {
433 for(struct addrinfo *aip = ai, *next; aip; aip = next) {
439 bool do_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
440 char *address, *port, *space;
441 struct addrinfo *proxyai = NULL;
446 if(!outgoing->ai && !outgoing->nai) {
448 logger(mesh, MESHLINK_ERROR, "Could not set up a meta connection to %s", outgoing->name);
449 retry_outgoing(mesh, outgoing);
453 get_config_string(outgoing->cfg, &address);
455 space = strchr(address, ' ');
458 port = xstrdup(space + 1);
461 // TODO: Only allow Address statements?
462 if(!get_config_string(lookup_config(outgoing->config_tree, "Port"), &port)) {
463 logger(mesh, MESHLINK_ERROR, "No Port known for %s", outgoing->name);
464 retry_outgoing(mesh, outgoing);
469 outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
473 outgoing->aip = outgoing->ai;
474 outgoing->cfg = lookup_config_next(outgoing->config_tree, outgoing->cfg);
479 freeaddrinfo(outgoing->ai);
485 free_known_addresses(outgoing->nai);
488 outgoing->nai = NULL;
493 connection_t *c = new_connection();
494 c->outgoing = outgoing;
496 memcpy(&c->address, outgoing->aip->ai_addr, outgoing->aip->ai_addrlen);
497 outgoing->aip = outgoing->aip->ai_next;
499 char *hostname = sockaddr2hostname(&c->address);
501 logger(mesh, MESHLINK_INFO, "Trying to connect to %s at %s", outgoing->name, hostname);
503 if(!mesh->proxytype) {
504 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
506 } else if(mesh->proxytype == PROXY_EXEC) {
507 do_outgoing_pipe(mesh, c, mesh->proxyhost);
509 proxyai = str2addrinfo(mesh->proxyhost, mesh->proxyport, SOCK_STREAM);
517 logger(mesh, MESHLINK_INFO, "Using proxy at %s port %s", mesh->proxyhost, mesh->proxyport);
518 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
522 if(c->socket == -1) {
523 logger(mesh, MESHLINK_ERROR, "Creating socket for %s at %s failed: %s", c->name, c->hostname, sockstrerror(sockerrno));
532 fcntl(c->socket, F_SETFD, FD_CLOEXEC);
535 if(mesh->proxytype != PROXY_EXEC) {
536 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
539 if(c->address.sa.sa_family == AF_INET6) {
540 setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
545 bind_to_address(mesh, c);
550 if(!mesh->proxytype) {
551 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
552 } else if(mesh->proxytype == PROXY_EXEC) {
555 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
556 freeaddrinfo(proxyai);
559 if(result == -1 && !sockinprogress(sockerrno)) {
560 logger(mesh, MESHLINK_ERROR, "Could not connect to %s: %s", outgoing->name, sockstrerror(sockerrno));
566 /* Now that there is a working socket, fill in the rest and register this connection. */
568 c->status.connecting = true;
569 c->name = xstrdup(outgoing->name);
570 c->outcompression = mesh->self->connection->outcompression;
571 c->last_ping_time = mesh->loop.now.tv_sec;
573 connection_add(mesh, c);
575 io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ | IO_WRITE);
580 void setup_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
581 bool blacklisted = false;
582 timeout_del(&mesh->loop, &outgoing->ev);
584 node_t *n = lookup_node(mesh, outgoing->name);
586 if(n && n->connection) {
587 logger(mesh, MESHLINK_INFO, "Already connected to %s", outgoing->name);
589 n->connection->outgoing = outgoing;
593 exit_configuration(&outgoing->config_tree); // discard old configuration if present
594 init_configuration(&outgoing->config_tree);
595 read_host_config(mesh, outgoing->config_tree, outgoing->name);
596 outgoing->cfg = lookup_config(outgoing->config_tree, "Address");
598 get_config_bool(lookup_config(outgoing->config_tree, "blacklisted"), &blacklisted);
606 outgoing->aip = outgoing->nai = get_known_addresses(n);
610 logger(mesh, MESHLINK_ERROR, "No address known for %s", outgoing->name);
615 do_outgoing_connection(mesh, outgoing);
619 accept a new tcp connect and create a
622 void handle_new_meta_connection(event_loop_t *loop, void *data, int flags) {
624 meshlink_handle_t *mesh = loop->data;
625 listen_socket_t *l = data;
629 socklen_t len = sizeof(sa);
631 fd = accept(l->tcp.fd, &sa.sa, &len);
634 if(errno == EINVAL) { // TODO: check if Windows agrees
635 event_loop_stop(loop);
639 logger(mesh, MESHLINK_ERROR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
645 // Check if we get many connections from the same host
647 static sockaddr_t prev_sa;
648 static int tarpit = -1;
655 if(!sockaddrcmp_noport(&sa, &prev_sa)) {
656 static int samehost_burst;
657 static int samehost_burst_time;
659 if(mesh->loop.now.tv_sec - samehost_burst_time > samehost_burst) {
662 samehost_burst -= mesh->loop.now.tv_sec - samehost_burst_time;
665 samehost_burst_time = mesh->loop.now.tv_sec;
668 if(samehost_burst > max_connection_burst) {
674 memcpy(&prev_sa, &sa, sizeof(sa));
676 // Check if we get many connections from different hosts
678 static int connection_burst;
679 static int connection_burst_time;
681 if(mesh->loop.now.tv_sec - connection_burst_time > connection_burst) {
682 connection_burst = 0;
684 connection_burst -= mesh->loop.now.tv_sec - connection_burst_time;
687 connection_burst_time = mesh->loop.now.tv_sec;
690 if(connection_burst >= max_connection_burst) {
691 connection_burst = max_connection_burst;
696 // Accept the new connection
698 c = new_connection();
699 c->name = xstrdup("<unknown>");
700 c->outcompression = mesh->self->connection->outcompression;
704 c->last_ping_time = mesh->loop.now.tv_sec;
706 char *hostname = sockaddr2hostname(&sa);
707 logger(mesh, MESHLINK_INFO, "Connection from %s", c->hostname);
710 io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ);
714 connection_add(mesh, c);
716 c->allow_request = ID;
720 static void free_outgoing(outgoing_t *outgoing) {
721 meshlink_handle_t *mesh = outgoing->mesh;
723 timeout_del(&mesh->loop, &outgoing->ev);
726 freeaddrinfo(outgoing->ai);
730 free_known_addresses(outgoing->nai);
733 if(outgoing->config_tree) {
734 exit_configuration(&outgoing->config_tree);
738 free(outgoing->name);
744 void try_outgoing_connections(meshlink_handle_t *mesh) {
745 /* If there is no outgoing list yet, create one. Otherwise, mark all outgoings as deleted. */
747 if(!mesh->outgoings) {
748 mesh->outgoings = list_alloc((list_action_t)free_outgoing);
750 for list_each(outgoing_t, outgoing, mesh->outgoings) {
751 outgoing->timeout = -1;
755 /* Make sure there is one outgoing_t in the list for each ConnectTo. */
757 // TODO: Drop support for ConnectTo since AutoConnect is now always on?
758 for(config_t *cfg = lookup_config(mesh->config, "ConnectTo"); cfg; cfg = lookup_config_next(mesh->config, cfg)) {
760 get_config_string(cfg, &name);
762 if(!check_id(name)) {
763 logger(mesh, MESHLINK_ERROR,
764 "Invalid name for outgoing connection in %s line %d",
765 cfg->file, cfg->line);
772 for list_each(outgoing_t, outgoing, mesh->outgoings) {
773 if(!strcmp(outgoing->name, name)) {
775 outgoing->timeout = 0;
781 outgoing_t *outgoing = xzalloc(sizeof(*outgoing));
782 outgoing->mesh = mesh;
783 outgoing->name = name;
784 list_insert_tail(mesh->outgoings, outgoing);
785 setup_outgoing_connection(mesh, outgoing);
789 /* Terminate any connections whose outgoing_t is to be deleted. */
791 for list_each(connection_t, c, mesh->connections) {
792 if(c->outgoing && c->outgoing->timeout == -1) {
794 logger(mesh, MESHLINK_INFO, "No more outgoing connection to %s", c->name);
795 terminate_connection(mesh, c, c->status.active);
799 /* Delete outgoing_ts for which there is no ConnectTo. */
801 for list_each(outgoing_t, outgoing, mesh->outgoings)
802 if(outgoing->timeout == -1) {
803 list_delete_node(mesh->outgoings, node);