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(IP_TOS) && defined(IPTOS_LOWDELAY)
72 int lowdelay = IPTOS_LOWDELAY;
73 setsockopt(c->socket, IPPROTO_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(IPV6_V6ONLY)
135 if(sa->sa.sa_family == AF_INET6) {
136 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
140 #warning IPV6_V6ONLY not defined
143 if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
145 addrstr = sockaddr2hostname(sa);
146 logger(NULL, MESHLINK_ERROR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
153 logger(NULL, MESHLINK_ERROR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
160 int setup_vpn_in_socket(meshlink_handle_t *mesh, const sockaddr_t *sa) {
165 nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
168 logger(mesh, MESHLINK_ERROR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
173 fcntl(nfd, F_SETFD, FD_CLOEXEC);
178 int flags = fcntl(nfd, F_GETFL);
180 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
182 logger(mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "fcntl",
189 unsigned long arg = 1;
191 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
193 logger(mesh, MESHLINK_ERROR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
200 setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
201 setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof(option));
203 #if defined(IPV6_V6ONLY)
205 if(sa->sa.sa_family == AF_INET6) {
206 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
211 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
212 #define IP_DONTFRAGMENT IP_DONTFRAG
215 #if defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
217 if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
218 option = IP_PMTUDISC_DO;
219 setsockopt(nfd, IPPROTO_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
222 #elif defined(IP_DONTFRAGMENT)
224 if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
226 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
230 #warning No way to disable IPv4 fragmentation
233 #if defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
235 if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
236 option = IPV6_PMTUDISC_DO;
237 setsockopt(nfd, IPPROTO_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
240 #elif defined(IPV6_DONTFRAG)
242 if(mesh->self->options & OPTION_PMTU_DISCOVERY) {
244 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
248 #warning No way to disable IPv6 fragmentation
251 if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
253 addrstr = sockaddr2hostname(sa);
254 logger(mesh, MESHLINK_ERROR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
260 } /* int setup_vpn_in_socket */
262 static void retry_outgoing_handler(event_loop_t *loop, void *data) {
263 meshlink_handle_t *mesh = loop->data;
264 outgoing_t *outgoing = data;
265 setup_outgoing_connection(mesh, outgoing);
268 void retry_outgoing(meshlink_handle_t *mesh, outgoing_t *outgoing) {
269 outgoing->timeout += 5;
271 if(outgoing->timeout > mesh->maxtimeout) {
272 outgoing->timeout = mesh->maxtimeout;
275 timeout_add(&mesh->loop, &outgoing->ev, retry_outgoing_handler, outgoing, &(struct timeval) {
276 outgoing->timeout, rand() % 100000
279 logger(mesh, MESHLINK_INFO, "Trying to re-establish outgoing connection in %d seconds", outgoing->timeout);
282 void finish_connecting(meshlink_handle_t *mesh, connection_t *c) {
283 logger(mesh, MESHLINK_INFO, "Connected to %s", c->name);
285 c->last_ping_time = mesh->loop.now.tv_sec;
286 c->status.connecting = false;
291 static void handle_meta_write(meshlink_handle_t *mesh, connection_t *c) {
292 if(c->outbuf.len <= c->outbuf.offset) {
296 ssize_t outlen = send(c->socket, c->outbuf.data + c->outbuf.offset, c->outbuf.len - c->outbuf.offset, MSG_NOSIGNAL);
299 if(!errno || errno == EPIPE) {
300 logger(mesh, MESHLINK_INFO, "Connection closed by %s", c->name);
301 } else if(sockwouldblock(sockerrno)) {
302 logger(mesh, MESHLINK_DEBUG, "Sending %lu bytes to %s would block", (unsigned long)(c->outbuf.len - c->outbuf.offset), c->name);
305 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));
308 terminate_connection(mesh, c, c->status.active);
312 buffer_read(&c->outbuf, outlen);
315 io_set(&mesh->loop, &c->io, IO_READ);
319 static void handle_meta_io(event_loop_t *loop, void *data, int flags) {
320 meshlink_handle_t *mesh = loop->data;
321 connection_t *c = data;
323 if(c->status.connecting) {
324 c->status.connecting = false;
327 socklen_t len = sizeof(result);
328 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&result, &len);
331 finish_connecting(mesh, c);
333 logger(mesh, MESHLINK_DEBUG, "Error while connecting to %s: %s", c->name, sockstrerror(result));
334 terminate_connection(mesh, c, false);
339 if(flags & IO_WRITE) {
340 handle_meta_write(mesh, c);
342 handle_meta_connection_data(mesh, c);
346 // Find edges pointing to this node, and use them to build a list of unique, known addresses.
347 static struct addrinfo *get_known_addresses(node_t *n) {
348 struct addrinfo *ai = NULL;
350 for splay_each(edge_t, e, n->edge_tree) {
357 for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
358 if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
368 // Create a new struct addrinfo, and put it at the head of the list.
369 struct addrinfo *nai = xzalloc(sizeof(*nai) + SALEN(e->reverse->address.sa));
373 ai->ai_family = e->reverse->address.sa.sa_family;
374 ai->ai_socktype = SOCK_STREAM;
375 ai->ai_protocol = IPPROTO_TCP;
376 ai->ai_addrlen = SALEN(e->reverse->address.sa);
377 ai->ai_addr = (struct sockaddr *)(nai + 1);
378 memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
384 // Free struct addrinfo list from get_known_addresses().
385 static void free_known_addresses(struct addrinfo *ai) {
386 for(struct addrinfo *aip = ai, *next; aip; aip = next) {
392 static bool get_recent(meshlink_handle_t *mesh, outgoing_t *outgoing) {
393 node_t *n = lookup_node(mesh, outgoing->name);
399 outgoing->ai = get_known_addresses(n);
400 outgoing->aip = outgoing->ai;
401 return outgoing->aip;
404 static bool get_next_ai(meshlink_handle_t *mesh, outgoing_t *outgoing) {
406 char *address = NULL;
408 if(get_config_string(outgoing->cfg, &address)) {
410 char *space = strchr(address, ' ');
413 port = xstrdup(space + 1);
416 if(!get_config_string(lookup_config(outgoing->config_tree, "Port"), &port)) {
417 logger(mesh, MESHLINK_ERROR, "No Port known for %s", outgoing->name);
422 outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
427 outgoing->aip = outgoing->ai;
429 outgoing->aip = outgoing->aip->ai_next;
432 return outgoing->aip;
435 static bool get_next_cfg(meshlink_handle_t *mesh, outgoing_t *outgoing, char *variable) {
439 outgoing->cfg = lookup_config(outgoing->config_tree, variable);
441 outgoing->cfg = lookup_config_next(outgoing->config_tree, outgoing->cfg);
444 return outgoing->cfg;
447 static bool get_next_outgoing_address(meshlink_handle_t *mesh, outgoing_t *outgoing) {
450 if(outgoing->state == OUTGOING_START) {
452 outgoing->state = OUTGOING_CANONICAL;
455 if(outgoing->state == OUTGOING_CANONICAL) {
456 if(outgoing->aip || get_next_cfg(mesh, outgoing, "CanonicalAddress")) {
457 if(get_next_ai(mesh, outgoing)) {
460 freeaddrinfo(outgoing->ai);
462 outgoing->aip = NULL;
466 outgoing->state = OUTGOING_RECENT;
469 if(outgoing->state == OUTGOING_RECENT) {
470 if(outgoing->aip || get_next_cfg(mesh, outgoing, "Address")) {
471 if(get_next_ai(mesh, outgoing)) {
474 freeaddrinfo(outgoing->ai);
476 outgoing->aip = NULL;
480 outgoing->state = OUTGOING_KNOWN;
483 if(outgoing->state == OUTGOING_KNOWN) {
484 if(outgoing->aip || get_recent(mesh, outgoing)) {
485 if(get_next_ai(mesh, outgoing)) {
488 free_known_addresses(outgoing->ai);
490 outgoing->aip = NULL;
494 outgoing->state = OUTGOING_END;
498 outgoing->state = OUTGOING_NO_KNOWN_ADDRESSES;
504 bool do_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
505 struct addrinfo *proxyai = NULL;
510 if(!get_next_outgoing_address(mesh, outgoing)) {
511 if(outgoing->state == OUTGOING_NO_KNOWN_ADDRESSES) {
512 logger(mesh, MESHLINK_ERROR, "No known addresses for %s", outgoing->name);
514 logger(mesh, MESHLINK_ERROR, "Could not set up a meta connection to %s", outgoing->name);
515 retry_outgoing(mesh, outgoing);
521 connection_t *c = new_connection();
522 c->outgoing = outgoing;
524 memcpy(&c->address, outgoing->aip->ai_addr, outgoing->aip->ai_addrlen);
526 char *hostname = sockaddr2hostname(&c->address);
528 logger(mesh, MESHLINK_INFO, "Trying to connect to %s at %s", outgoing->name, hostname);
530 if(!mesh->proxytype) {
531 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
534 proxyai = str2addrinfo(mesh->proxyhost, mesh->proxyport, SOCK_STREAM);
542 logger(mesh, MESHLINK_INFO, "Using proxy at %s port %s", mesh->proxyhost, mesh->proxyport);
543 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
547 if(c->socket == -1) {
548 logger(mesh, MESHLINK_ERROR, "Creating socket for %s at %s failed: %s", c->name, hostname, sockstrerror(sockerrno));
557 fcntl(c->socket, F_SETFD, FD_CLOEXEC);
560 #if defined(IPV6_V6ONLY)
562 if(c->address.sa.sa_family == AF_INET6) {
563 static const int option = 1;
564 setsockopt(c->socket, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
569 bind_to_address(mesh, c);
573 if(!mesh->proxytype) {
574 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
576 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
577 freeaddrinfo(proxyai);
580 if(result == -1 && !sockinprogress(sockerrno)) {
581 logger(mesh, MESHLINK_ERROR, "Could not connect to %s: %s", outgoing->name, sockstrerror(sockerrno));
587 /* Now that there is a working socket, fill in the rest and register this connection. */
589 c->status.connecting = true;
590 c->name = xstrdup(outgoing->name);
591 c->outcompression = mesh->self->connection->outcompression;
592 c->last_ping_time = mesh->loop.now.tv_sec;
594 connection_add(mesh, c);
596 io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ | IO_WRITE);
601 void setup_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
602 bool blacklisted = false;
603 timeout_del(&mesh->loop, &outgoing->ev);
605 node_t *n = lookup_node(mesh, outgoing->name);
607 if(n && n->connection) {
608 logger(mesh, MESHLINK_INFO, "Already connected to %s", outgoing->name);
610 n->connection->outgoing = outgoing;
616 if(outgoing->state == OUTGOING_KNOWN) {
617 free_known_addresses(outgoing->ai);
619 freeaddrinfo(outgoing->ai);
623 outgoing->cfg = NULL;
625 exit_configuration(&outgoing->config_tree); // discard old configuration if present
626 init_configuration(&outgoing->config_tree);
627 read_host_config(mesh, outgoing->config_tree, outgoing->name);
628 get_config_bool(lookup_config(outgoing->config_tree, "blacklisted"), &blacklisted);
630 outgoing->state = OUTGOING_START;
636 do_outgoing_connection(mesh, outgoing);
640 accept a new tcp connect and create a
643 void handle_new_meta_connection(event_loop_t *loop, void *data, int flags) {
645 meshlink_handle_t *mesh = loop->data;
646 listen_socket_t *l = data;
650 socklen_t len = sizeof(sa);
652 fd = accept(l->tcp.fd, &sa.sa, &len);
655 if(errno == EINVAL) { // TODO: check if Windows agrees
656 event_loop_stop(loop);
660 logger(mesh, MESHLINK_ERROR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
666 // Check if we get many connections from the same host
668 static sockaddr_t prev_sa;
669 static int tarpit = -1;
676 if(!sockaddrcmp_noport(&sa, &prev_sa)) {
677 static int samehost_burst;
678 static int samehost_burst_time;
680 if(mesh->loop.now.tv_sec - samehost_burst_time > samehost_burst) {
683 samehost_burst -= mesh->loop.now.tv_sec - samehost_burst_time;
686 samehost_burst_time = mesh->loop.now.tv_sec;
689 if(samehost_burst > max_connection_burst) {
695 memcpy(&prev_sa, &sa, sizeof(sa));
697 // Check if we get many connections from different hosts
699 static int connection_burst;
700 static int connection_burst_time;
702 if(mesh->loop.now.tv_sec - connection_burst_time > connection_burst) {
703 connection_burst = 0;
705 connection_burst -= mesh->loop.now.tv_sec - connection_burst_time;
708 connection_burst_time = mesh->loop.now.tv_sec;
711 if(connection_burst >= max_connection_burst) {
712 connection_burst = max_connection_burst;
717 // Accept the new connection
719 c = new_connection();
720 c->name = xstrdup("<unknown>");
721 c->outcompression = mesh->self->connection->outcompression;
725 c->last_ping_time = mesh->loop.now.tv_sec;
727 char *hostname = sockaddr2hostname(&sa);
728 logger(mesh, MESHLINK_INFO, "Connection from %s", hostname);
731 io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ);
735 connection_add(mesh, c);
737 c->allow_request = ID;
741 static void free_outgoing(outgoing_t *outgoing) {
742 meshlink_handle_t *mesh = outgoing->mesh;
744 timeout_del(&mesh->loop, &outgoing->ev);
747 if(outgoing->state == OUTGOING_KNOWN) {
748 free_known_addresses(outgoing->ai);
750 freeaddrinfo(outgoing->ai);
754 if(outgoing->config_tree) {
755 exit_configuration(&outgoing->config_tree);
759 free(outgoing->name);
765 void try_outgoing_connections(meshlink_handle_t *mesh) {
766 /* If there is no outgoing list yet, create one. Otherwise, mark all outgoings as deleted. */
768 if(!mesh->outgoings) {
769 mesh->outgoings = list_alloc((list_action_t)free_outgoing);
771 for list_each(outgoing_t, outgoing, mesh->outgoings) {
772 outgoing->timeout = -1;
776 /* Make sure there is one outgoing_t in the list for each ConnectTo. */
778 // TODO: Drop support for ConnectTo since AutoConnect is now always on?
779 for(config_t *cfg = lookup_config(mesh->config, "ConnectTo"); cfg; cfg = lookup_config_next(mesh->config, cfg)) {
781 get_config_string(cfg, &name);
783 if(!check_id(name)) {
784 logger(mesh, MESHLINK_ERROR,
785 "Invalid name for outgoing connection in line %d",
793 for list_each(outgoing_t, outgoing, mesh->outgoings) {
794 if(!strcmp(outgoing->name, name)) {
796 outgoing->timeout = 0;
802 outgoing_t *outgoing = xzalloc(sizeof(*outgoing));
803 outgoing->mesh = mesh;
804 outgoing->name = name;
805 list_insert_tail(mesh->outgoings, outgoing);
806 setup_outgoing_connection(mesh, outgoing);
810 /* Terminate any connections whose outgoing_t is to be deleted. */
812 for list_each(connection_t, c, mesh->connections) {
813 if(c->outgoing && c->outgoing->timeout == -1) {
815 logger(mesh, MESHLINK_INFO, "No more outgoing connection to %s", c->name);
816 terminate_connection(mesh, c, c->status.active);
820 /* Delete outgoing_ts for which there is no ConnectTo. */
822 for list_each(outgoing_t, outgoing, mesh->outgoings)
823 if(outgoing->timeout == -1) {
824 list_delete_node(mesh->outgoings, node);