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.
24 #include "connection.h"
27 #include "meshlink_internal.h"
35 /* Needed on Mac OS/X */
37 #define SOL_TCP IPPROTO_TCP
41 #define MSG_NOSIGNAL 0
44 static const int max_connection_burst = 100;
48 static void configure_tcp(connection_t *c) {
50 int flags = fcntl(c->socket, F_GETFL);
52 if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
53 logger(c->mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "fcntl", strerror(errno));
57 unsigned long arg = 1;
59 if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
60 logger(c->mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
65 #if defined(SOL_TCP) && defined(TCP_NODELAY)
67 setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&nodelay, sizeof(nodelay));
70 #if defined(IP_TOS) && defined(IPTOS_LOWDELAY)
71 int lowdelay = IPTOS_LOWDELAY;
72 setsockopt(c->socket, IPPROTO_IP, IP_TOS, (void *)&lowdelay, sizeof(lowdelay));
76 static void retry_outgoing_handler(event_loop_t *loop, void *data) {
79 meshlink_handle_t *mesh = loop->data;
80 outgoing_t *outgoing = data;
81 setup_outgoing_connection(mesh, outgoing);
84 void retry_outgoing(meshlink_handle_t *mesh, outgoing_t *outgoing) {
85 if(!mesh->reachable && mesh->loop.now.tv_sec < mesh->last_unreachable + mesh->dev_class_traits[mesh->devclass].fast_retry_period) {
86 outgoing->timeout = 1;
88 outgoing->timeout += 5;
91 if(outgoing->timeout > mesh->maxtimeout) {
92 outgoing->timeout = mesh->maxtimeout;
95 timeout_add(&mesh->loop, &outgoing->ev, retry_outgoing_handler, outgoing, &(struct timespec) {
96 outgoing->timeout, prng(mesh, TIMER_FUDGE)
99 logger(mesh, MESHLINK_INFO, "Trying to re-establish outgoing connection in %d seconds", outgoing->timeout);
102 void finish_connecting(meshlink_handle_t *mesh, connection_t *c) {
103 logger(mesh, MESHLINK_INFO, "Connected to %s", c->name);
105 c->last_ping_time = mesh->loop.now.tv_sec;
106 c->status.connecting = false;
111 static void handle_meta_write(meshlink_handle_t *mesh, connection_t *c) {
112 if(c->outbuf.len <= c->outbuf.offset) {
116 ssize_t outlen = send(c->socket, c->outbuf.data + c->outbuf.offset, c->outbuf.len - c->outbuf.offset, MSG_NOSIGNAL);
119 if(!errno || errno == EPIPE) {
120 logger(mesh, MESHLINK_INFO, "Connection closed by %s", c->name);
121 } else if(sockwouldblock(sockerrno)) {
122 logger(mesh, MESHLINK_DEBUG, "Sending %lu bytes to %s would block", (unsigned long)(c->outbuf.len - c->outbuf.offset), c->name);
125 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));
128 terminate_connection(mesh, c, c->status.active);
132 buffer_read(&c->outbuf, outlen);
135 io_set(&mesh->loop, &c->io, IO_READ);
139 static void handle_meta_io(event_loop_t *loop, void *data, int flags) {
140 meshlink_handle_t *mesh = loop->data;
141 connection_t *c = data;
143 if(c->status.connecting) {
144 c->status.connecting = false;
147 socklen_t len = sizeof(result);
148 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&result, &len);
151 finish_connecting(mesh, c);
153 logger(mesh, MESHLINK_DEBUG, "Error while connecting to %s: %s", c->name, sockstrerror(result));
154 terminate_connection(mesh, c, false);
159 if(flags & IO_WRITE) {
160 handle_meta_write(mesh, c);
162 handle_meta_connection_data(mesh, c);
166 // Find edges pointing to this node, and use them to build a list of unique, known addresses.
167 static struct addrinfo *get_known_addresses(node_t *n) {
168 struct addrinfo *ai = NULL;
170 for splay_each(edge_t, e, n->edge_tree) {
177 for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
178 if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
188 // Create a new struct addrinfo, and put it at the head of the list.
189 struct addrinfo *nai = xzalloc(sizeof(*nai) + SALEN(e->reverse->address.sa));
193 ai->ai_family = e->reverse->address.sa.sa_family;
194 ai->ai_socktype = SOCK_STREAM;
195 ai->ai_protocol = IPPROTO_TCP;
196 ai->ai_addrlen = SALEN(e->reverse->address.sa);
197 ai->ai_addr = (struct sockaddr *)(nai + 1);
198 memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
204 // Build a list of recently seen addresses.
205 static struct addrinfo *get_recent_addresses(node_t *n) {
206 struct addrinfo *ai = NULL;
207 struct addrinfo *aip;
209 for(int i = 0; i < 5; i++) {
210 if(!n->recent[i].sa.sa_family) {
214 // Create a new struct addrinfo, and put it at the end of the list.
215 struct addrinfo *nai = xzalloc(sizeof(*nai) + SALEN(n->recent[i].sa));
225 nai->ai_family = n->recent[i].sa.sa_family;
226 nai->ai_socktype = SOCK_STREAM;
227 nai->ai_protocol = IPPROTO_TCP;
228 nai->ai_addrlen = SALEN(n->recent[i].sa);
229 nai->ai_addr = (struct sockaddr *)(nai + 1);
230 memcpy(nai->ai_addr, &n->recent[i], nai->ai_addrlen);
236 // Free struct addrinfo list from get_known_addresses().
237 static void free_known_addresses(struct addrinfo *ai) {
238 for(struct addrinfo *aip = ai, *next; aip; aip = next) {
244 static void canonical_resolve_cb(meshlink_handle_t *mesh, char *host, char *serv, void *data, struct addrinfo *ai, int err) {
252 for list_each(outgoing_t, outgoing, mesh->outgoings) {
253 if(outgoing->node == n) {
254 if(outgoing->state == OUTGOING_CANONICAL_RESOLVE) {
256 outgoing->aip = NULL;
257 outgoing->state = OUTGOING_CANONICAL;
258 do_outgoing_connection(mesh, outgoing);
266 static bool get_next_outgoing_address(meshlink_handle_t *mesh, outgoing_t *outgoing) {
271 if(outgoing->state == OUTGOING_START) {
273 outgoing->state = OUTGOING_CANONICAL_RESOLVE;
276 if(outgoing->state == OUTGOING_CANONICAL_RESOLVE) {
277 node_t *n = outgoing->node;
279 if(n->canonical_address) {
280 char *address = xstrdup(n->canonical_address);
281 char *port = strchr(address, ' ');
285 port = xstrdup(port);
286 adns_queue(mesh, address, port, canonical_resolve_cb, outgoing->node, 2);
289 logger(mesh, MESHLINK_ERROR, "Canonical address for %s is missing port number", n->name);
291 outgoing->state = OUTGOING_RECENT;
295 outgoing->state = OUTGOING_RECENT;
299 if(outgoing->state == OUTGOING_CANONICAL) {
301 outgoing->aip = outgoing->ai;
303 outgoing->aip = outgoing->aip->ai_next;
311 freeaddrinfo(outgoing->ai);
315 outgoing->aip = NULL;
316 outgoing->state = OUTGOING_RECENT;
319 if(outgoing->state == OUTGOING_RECENT) {
321 outgoing->ai = get_recent_addresses(outgoing->node);
322 outgoing->aip = outgoing->ai;
324 outgoing->aip = outgoing->aip->ai_next;
331 free_known_addresses(outgoing->ai);
333 outgoing->aip = NULL;
334 outgoing->state = OUTGOING_KNOWN;
337 if(outgoing->state == OUTGOING_KNOWN) {
339 outgoing->ai = get_known_addresses(outgoing->node);
340 outgoing->aip = outgoing->ai;
342 outgoing->aip = outgoing->aip->ai_next;
349 free_known_addresses(outgoing->ai);
351 outgoing->aip = NULL;
352 outgoing->state = OUTGOING_END;
356 outgoing->state = OUTGOING_NO_KNOWN_ADDRESSES;
362 void do_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
365 if(!get_next_outgoing_address(mesh, outgoing)) {
366 if(outgoing->state == OUTGOING_CANONICAL_RESOLVE) {
367 /* We are waiting for a callback from the ADNS thread */
368 } else if(outgoing->state == OUTGOING_NO_KNOWN_ADDRESSES) {
369 logger(mesh, MESHLINK_ERROR, "No known addresses for %s", outgoing->node->name);
371 logger(mesh, MESHLINK_ERROR, "Could not set up a meta connection to %s", outgoing->node->name);
372 retry_outgoing(mesh, outgoing);
378 connection_t *c = new_connection();
379 c->outgoing = outgoing;
381 memcpy(&c->address, outgoing->aip->ai_addr, outgoing->aip->ai_addrlen);
383 if(mesh->log_level <= MESHLINK_INFO) {
384 char *hostname = sockaddr2hostname(&c->address);
385 logger(mesh, MESHLINK_INFO, "Trying to connect to %s at %s", outgoing->node->name, hostname);
389 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
391 if(c->socket == -1) {
392 if(mesh->log_level <= MESHLINK_ERROR) {
393 char *hostname = sockaddr2hostname(&c->address);
394 logger(mesh, MESHLINK_ERROR, "Creating socket for %s at %s failed: %s", c->name, hostname, sockstrerror(sockerrno));
405 fcntl(c->socket, F_SETFD, FD_CLOEXEC);
408 #if defined(IPV6_V6ONLY)
410 if(c->address.sa.sa_family == AF_INET6) {
411 static const int option = 1;
412 setsockopt(c->socket, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
419 int result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
421 if(result == -1 && !sockinprogress(sockerrno)) {
422 if(mesh->log_level <= MESHLINK_ERROR) {
423 char *hostname = sockaddr2hostname(&c->address);
424 logger(mesh, MESHLINK_ERROR, "Could not connect to %s: %s", outgoing->node->name, sockstrerror(sockerrno));
432 /* Now that there is a working socket, fill in the rest and register this connection. */
434 c->status.connecting = true;
435 c->status.initiator = true;
436 c->name = xstrdup(outgoing->node->name);
437 c->last_ping_time = mesh->loop.now.tv_sec;
439 connection_add(mesh, c);
441 io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ | IO_WRITE);
444 void reset_outgoing(outgoing_t *outgoing) {
446 if(outgoing->state == OUTGOING_RECENT || outgoing->state == OUTGOING_KNOWN) {
447 free_known_addresses(outgoing->ai);
449 freeaddrinfo(outgoing->ai);
454 outgoing->aip = NULL;
455 outgoing->state = OUTGOING_START;
458 void setup_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
459 timeout_del(&mesh->loop, &outgoing->ev);
461 if(outgoing->node->connection) {
462 logger(mesh, MESHLINK_INFO, "Already connected to %s", outgoing->node->name);
464 outgoing->node->connection->outgoing = outgoing;
468 reset_outgoing(outgoing);
470 if(outgoing->node->status.blacklisted) {
474 if(mesh->connection_try_cb) {
475 mesh->connection_try_cb(mesh, (meshlink_node_t *)outgoing->node);
478 do_outgoing_connection(mesh, outgoing);
481 /// Delayed close of a filedescriptor.
482 static void tarpit(meshlink_handle_t *mesh, int fd) {
487 if(mesh->pits[mesh->next_pit]) {
488 closesocket(mesh->pits[mesh->next_pit]);
491 mesh->pits[mesh->next_pit++] = fd;
493 if(mesh->next_pit >= (int)(sizeof mesh->pits / sizeof mesh->pits[0])) {
499 accept a new tcp connect and create a
502 void handle_new_meta_connection(event_loop_t *loop, void *data, int flags) {
504 meshlink_handle_t *mesh = loop->data;
505 listen_socket_t *l = data;
509 socklen_t len = sizeof(sa);
511 memset(&sa, 0, sizeof(sa));
513 fd = accept(l->tcp.fd, &sa.sa, &len);
516 if(errno == EINVAL) { // TODO: check if Windows agrees
517 event_loop_stop(loop);
521 logger(mesh, MESHLINK_ERROR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
527 /* Rate limit incoming connections to max_connection_burst/second. */
529 if(mesh->loop.now.tv_sec != mesh->connection_burst_time) {
530 mesh->connection_burst_time = mesh->loop.now.tv_sec;
531 mesh->connection_burst = 0;
534 if(mesh->connection_burst >= max_connection_burst) {
539 mesh->connection_burst++;
541 // Accept the new connection
543 c = new_connection();
544 c->name = xstrdup("<unknown>");
548 c->last_ping_time = mesh->loop.now.tv_sec;
550 char *hostname = sockaddr2hostname(&sa);
551 logger(mesh, MESHLINK_INFO, "Connection from %s", hostname);
554 io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ);
558 connection_add(mesh, c);
560 c->allow_request = ID;
564 static void free_outgoing(outgoing_t *outgoing) {
565 meshlink_handle_t *mesh = outgoing->node->mesh;
567 timeout_del(&mesh->loop, &outgoing->ev);
570 if(outgoing->state == OUTGOING_RECENT || outgoing->state == OUTGOING_KNOWN) {
571 free_known_addresses(outgoing->ai);
573 freeaddrinfo(outgoing->ai);
580 void init_outgoings(meshlink_handle_t *mesh) {
581 mesh->outgoings = list_alloc((list_action_t)free_outgoing);
584 void exit_outgoings(meshlink_handle_t *mesh) {
585 if(mesh->outgoings) {
586 list_delete_list(mesh->outgoings);
587 mesh->outgoings = NULL;