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);
287 port = xstrdup(mesh->myport);
290 adns_queue(mesh, address, port, canonical_resolve_cb, outgoing->node, 2);
293 outgoing->state = OUTGOING_RECENT;
297 if(outgoing->state == OUTGOING_CANONICAL) {
299 outgoing->aip = outgoing->ai;
301 outgoing->aip = outgoing->aip->ai_next;
309 freeaddrinfo(outgoing->ai);
313 outgoing->aip = NULL;
314 outgoing->state = OUTGOING_RECENT;
317 if(outgoing->state == OUTGOING_RECENT) {
319 outgoing->ai = get_recent_addresses(outgoing->node);
320 outgoing->aip = outgoing->ai;
322 outgoing->aip = outgoing->aip->ai_next;
329 free_known_addresses(outgoing->ai);
331 outgoing->aip = NULL;
332 outgoing->state = OUTGOING_KNOWN;
335 if(outgoing->state == OUTGOING_KNOWN) {
337 outgoing->ai = get_known_addresses(outgoing->node);
338 outgoing->aip = outgoing->ai;
340 outgoing->aip = outgoing->aip->ai_next;
347 free_known_addresses(outgoing->ai);
349 outgoing->aip = NULL;
350 outgoing->state = OUTGOING_END;
354 outgoing->state = OUTGOING_NO_KNOWN_ADDRESSES;
360 void do_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
363 if(!get_next_outgoing_address(mesh, outgoing)) {
364 if(outgoing->state == OUTGOING_CANONICAL_RESOLVE) {
365 /* We are waiting for a callback from the ADNS thread */
366 } else if(outgoing->state == OUTGOING_NO_KNOWN_ADDRESSES) {
367 logger(mesh, MESHLINK_ERROR, "No known addresses for %s", outgoing->node->name);
369 logger(mesh, MESHLINK_ERROR, "Could not set up a meta connection to %s", outgoing->node->name);
370 retry_outgoing(mesh, outgoing);
376 connection_t *c = new_connection();
377 c->outgoing = outgoing;
379 memcpy(&c->address, outgoing->aip->ai_addr, outgoing->aip->ai_addrlen);
381 if(mesh->log_level <= MESHLINK_INFO) {
382 char *hostname = sockaddr2hostname(&c->address);
383 logger(mesh, MESHLINK_INFO, "Trying to connect to %s at %s", outgoing->node->name, hostname);
387 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
389 if(c->socket == -1) {
390 if(mesh->log_level <= MESHLINK_ERROR) {
391 char *hostname = sockaddr2hostname(&c->address);
392 logger(mesh, MESHLINK_ERROR, "Creating socket for %s at %s failed: %s", c->name, hostname, sockstrerror(sockerrno));
403 fcntl(c->socket, F_SETFD, FD_CLOEXEC);
406 #if defined(IPV6_V6ONLY)
408 if(c->address.sa.sa_family == AF_INET6) {
409 static const int option = 1;
410 setsockopt(c->socket, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
417 int result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
419 if(result == -1 && !sockinprogress(sockerrno)) {
420 if(mesh->log_level <= MESHLINK_ERROR) {
421 char *hostname = sockaddr2hostname(&c->address);
422 logger(mesh, MESHLINK_ERROR, "Could not connect to %s: %s", outgoing->node->name, sockstrerror(sockerrno));
430 /* Now that there is a working socket, fill in the rest and register this connection. */
432 c->status.connecting = true;
433 c->status.initiator = true;
434 c->name = xstrdup(outgoing->node->name);
435 c->last_ping_time = mesh->loop.now.tv_sec;
437 connection_add(mesh, c);
439 io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ | IO_WRITE);
442 void reset_outgoing(outgoing_t *outgoing) {
444 if(outgoing->state == OUTGOING_RECENT || outgoing->state == OUTGOING_KNOWN) {
445 free_known_addresses(outgoing->ai);
447 freeaddrinfo(outgoing->ai);
452 outgoing->aip = NULL;
453 outgoing->state = OUTGOING_START;
456 void setup_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
457 timeout_del(&mesh->loop, &outgoing->ev);
459 if(outgoing->node->connection) {
460 logger(mesh, MESHLINK_INFO, "Already connected to %s", outgoing->node->name);
462 outgoing->node->connection->outgoing = outgoing;
466 reset_outgoing(outgoing);
468 if(outgoing->node->status.blacklisted) {
472 if(mesh->connection_try_cb) {
473 mesh->connection_try_cb(mesh, (meshlink_node_t *)outgoing->node);
476 do_outgoing_connection(mesh, outgoing);
479 /// Delayed close of a filedescriptor.
480 static void tarpit(meshlink_handle_t *mesh, int fd) {
485 if(mesh->pits[mesh->next_pit]) {
486 closesocket(mesh->pits[mesh->next_pit]);
489 mesh->pits[mesh->next_pit++] = fd;
491 if(mesh->next_pit >= (int)(sizeof mesh->pits / sizeof mesh->pits[0])) {
497 accept a new tcp connect and create a
500 void handle_new_meta_connection(event_loop_t *loop, void *data, int flags) {
502 meshlink_handle_t *mesh = loop->data;
503 listen_socket_t *l = data;
507 socklen_t len = sizeof(sa);
509 memset(&sa, 0, sizeof(sa));
511 fd = accept(l->tcp.fd, &sa.sa, &len);
514 if(errno == EINVAL) { // TODO: check if Windows agrees
515 event_loop_stop(loop);
519 logger(mesh, MESHLINK_ERROR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
525 /* Rate limit incoming connections to max_connection_burst/second. */
527 if(mesh->loop.now.tv_sec != mesh->connection_burst_time) {
528 mesh->connection_burst_time = mesh->loop.now.tv_sec;
529 mesh->connection_burst = 0;
532 if(mesh->connection_burst >= max_connection_burst) {
537 mesh->connection_burst++;
539 // Accept the new connection
541 c = new_connection();
542 c->name = xstrdup("<unknown>");
546 c->last_ping_time = mesh->loop.now.tv_sec;
548 char *hostname = sockaddr2hostname(&sa);
549 logger(mesh, MESHLINK_INFO, "Connection from %s", hostname);
552 io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ);
556 connection_add(mesh, c);
558 c->allow_request = ID;
562 static void free_outgoing(outgoing_t *outgoing) {
563 meshlink_handle_t *mesh = outgoing->node->mesh;
565 timeout_del(&mesh->loop, &outgoing->ev);
568 if(outgoing->state == OUTGOING_RECENT || outgoing->state == OUTGOING_KNOWN) {
569 free_known_addresses(outgoing->ai);
571 freeaddrinfo(outgoing->ai);
578 void init_outgoings(meshlink_handle_t *mesh) {
579 mesh->outgoings = list_alloc((list_action_t)free_outgoing);
582 void exit_outgoings(meshlink_handle_t *mesh) {
583 if(mesh->outgoings) {
584 list_delete_list(mesh->outgoings);
585 mesh->outgoings = NULL;