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 static const int max_connection_burst = 100;
47 static void configure_tcp(connection_t *c) {
49 int flags = fcntl(c->socket, F_GETFL);
51 if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
52 logger(c->mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "fcntl", strerror(errno));
56 unsigned long arg = 1;
58 if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
59 logger(c->mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
64 #if defined(SOL_TCP) && defined(TCP_NODELAY)
66 setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&nodelay, sizeof(nodelay));
69 #if defined(IP_TOS) && defined(IPTOS_LOWDELAY)
70 int lowdelay = IPTOS_LOWDELAY;
71 setsockopt(c->socket, IPPROTO_IP, IP_TOS, (void *)&lowdelay, sizeof(lowdelay));
75 static void retry_outgoing_handler(event_loop_t *loop, void *data) {
78 meshlink_handle_t *mesh = loop->data;
79 outgoing_t *outgoing = data;
80 setup_outgoing_connection(mesh, outgoing);
83 void retry_outgoing(meshlink_handle_t *mesh, outgoing_t *outgoing) {
84 if(!mesh->reachable && mesh->loop.now.tv_sec < mesh->last_unreachable + mesh->dev_class_traits[mesh->devclass].fast_retry_period) {
85 outgoing->timeout = 1;
87 outgoing->timeout += 5;
90 if(outgoing->timeout > mesh->maxtimeout) {
91 outgoing->timeout = mesh->maxtimeout;
94 timeout_add(&mesh->loop, &outgoing->ev, retry_outgoing_handler, outgoing, &(struct timeval) {
95 outgoing->timeout, prng(mesh, TIMER_FUDGE)
98 logger(mesh, MESHLINK_INFO, "Trying to re-establish outgoing connection in %d seconds", outgoing->timeout);
101 void finish_connecting(meshlink_handle_t *mesh, connection_t *c) {
102 logger(mesh, MESHLINK_INFO, "Connected to %s", c->name);
104 c->last_ping_time = mesh->loop.now.tv_sec;
105 c->status.connecting = false;
110 static void handle_meta_write(meshlink_handle_t *mesh, connection_t *c) {
111 if(c->outbuf.len <= c->outbuf.offset) {
115 ssize_t outlen = send(c->socket, c->outbuf.data + c->outbuf.offset, c->outbuf.len - c->outbuf.offset, MSG_NOSIGNAL);
118 if(!errno || errno == EPIPE) {
119 logger(mesh, MESHLINK_INFO, "Connection closed by %s", c->name);
120 } else if(sockwouldblock(sockerrno)) {
121 logger(mesh, MESHLINK_DEBUG, "Sending %lu bytes to %s would block", (unsigned long)(c->outbuf.len - c->outbuf.offset), c->name);
124 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));
127 terminate_connection(mesh, c, c->status.active);
131 buffer_read(&c->outbuf, outlen);
134 io_set(&mesh->loop, &c->io, IO_READ);
138 static void handle_meta_io(event_loop_t *loop, void *data, int flags) {
139 meshlink_handle_t *mesh = loop->data;
140 connection_t *c = data;
142 if(c->status.connecting) {
143 c->status.connecting = false;
146 socklen_t len = sizeof(result);
147 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&result, &len);
150 finish_connecting(mesh, c);
152 logger(mesh, MESHLINK_DEBUG, "Error while connecting to %s: %s", c->name, sockstrerror(result));
153 terminate_connection(mesh, c, false);
158 if(flags & IO_WRITE) {
159 handle_meta_write(mesh, c);
161 handle_meta_connection_data(mesh, c);
165 // Find edges pointing to this node, and use them to build a list of unique, known addresses.
166 static struct addrinfo *get_known_addresses(node_t *n) {
167 struct addrinfo *ai = NULL;
169 for splay_each(edge_t, e, n->edge_tree) {
176 for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
177 if(!sockaddrcmp(&e->reverse->address, (sockaddr_t *)aip->ai_addr)) {
187 // Create a new struct addrinfo, and put it at the head of the list.
188 struct addrinfo *nai = xzalloc(sizeof(*nai) + SALEN(e->reverse->address.sa));
192 ai->ai_family = e->reverse->address.sa.sa_family;
193 ai->ai_socktype = SOCK_STREAM;
194 ai->ai_protocol = IPPROTO_TCP;
195 ai->ai_addrlen = SALEN(e->reverse->address.sa);
196 ai->ai_addr = (struct sockaddr *)(nai + 1);
197 memcpy(ai->ai_addr, &e->reverse->address, ai->ai_addrlen);
203 // Build a list of recently seen addresses.
204 static struct addrinfo *get_recent_addresses(node_t *n) {
205 struct addrinfo *ai = NULL;
206 struct addrinfo *aip;
208 for(int i = 0; i < 5; i++) {
209 if(!n->recent[i].sa.sa_family) {
213 // Create a new struct addrinfo, and put it at the end of the list.
214 struct addrinfo *nai = xzalloc(sizeof(*nai) + SALEN(n->recent[i].sa));
224 nai->ai_family = n->recent[i].sa.sa_family;
225 nai->ai_socktype = SOCK_STREAM;
226 nai->ai_protocol = IPPROTO_TCP;
227 nai->ai_addrlen = SALEN(n->recent[i].sa);
228 nai->ai_addr = (struct sockaddr *)(nai + 1);
229 memcpy(nai->ai_addr, &n->recent[i], nai->ai_addrlen);
235 // Free struct addrinfo list from get_known_addresses().
236 static void free_known_addresses(struct addrinfo *ai) {
237 for(struct addrinfo *aip = ai, *next; aip; aip = next) {
243 static struct addrinfo *get_canonical_address(node_t *n) {
244 if(!n->canonical_address) {
248 char *address = xstrdup(n->canonical_address);
249 char *port = strchr(address, ' ');
258 struct addrinfo *ai = str2addrinfo(address, port, SOCK_STREAM);
264 static bool get_next_outgoing_address(meshlink_handle_t *mesh, outgoing_t *outgoing) {
269 if(outgoing->state == OUTGOING_START) {
271 outgoing->state = OUTGOING_CANONICAL;
274 if(outgoing->state == OUTGOING_CANONICAL) {
276 outgoing->ai = get_canonical_address(outgoing->node);
277 outgoing->aip = outgoing->ai;
279 outgoing->aip = outgoing->aip->ai_next;
286 freeaddrinfo(outgoing->ai);
288 outgoing->aip = NULL;
289 outgoing->state = OUTGOING_RECENT;
292 if(outgoing->state == OUTGOING_RECENT) {
294 outgoing->ai = get_recent_addresses(outgoing->node);
295 outgoing->aip = outgoing->ai;
297 outgoing->aip = outgoing->aip->ai_next;
304 free_known_addresses(outgoing->ai);
306 outgoing->aip = NULL;
307 outgoing->state = OUTGOING_KNOWN;
310 if(outgoing->state == OUTGOING_KNOWN) {
312 outgoing->ai = get_known_addresses(outgoing->node);
313 outgoing->aip = outgoing->ai;
315 outgoing->aip = outgoing->aip->ai_next;
322 free_known_addresses(outgoing->ai);
324 outgoing->aip = NULL;
325 outgoing->state = OUTGOING_END;
329 outgoing->state = OUTGOING_NO_KNOWN_ADDRESSES;
335 void do_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
336 struct addrinfo *proxyai = NULL;
341 if(!get_next_outgoing_address(mesh, outgoing)) {
342 if(outgoing->state == OUTGOING_NO_KNOWN_ADDRESSES) {
343 logger(mesh, MESHLINK_ERROR, "No known addresses for %s", outgoing->node->name);
345 logger(mesh, MESHLINK_ERROR, "Could not set up a meta connection to %s", outgoing->node->name);
346 retry_outgoing(mesh, outgoing);
352 connection_t *c = new_connection();
353 c->outgoing = outgoing;
355 memcpy(&c->address, outgoing->aip->ai_addr, outgoing->aip->ai_addrlen);
357 char *hostname = sockaddr2hostname(&c->address);
359 logger(mesh, MESHLINK_INFO, "Trying to connect to %s at %s", outgoing->node->name, hostname);
361 if(!mesh->proxytype) {
362 c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
365 proxyai = str2addrinfo(mesh->proxyhost, mesh->proxyport, SOCK_STREAM);
373 logger(mesh, MESHLINK_INFO, "Using proxy at %s port %s", mesh->proxyhost, mesh->proxyport);
374 c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
378 if(c->socket == -1) {
379 logger(mesh, MESHLINK_ERROR, "Creating socket for %s at %s failed: %s", c->name, hostname, sockstrerror(sockerrno));
388 fcntl(c->socket, F_SETFD, FD_CLOEXEC);
391 #if defined(IPV6_V6ONLY)
393 if(c->address.sa.sa_family == AF_INET6) {
394 static const int option = 1;
395 setsockopt(c->socket, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
402 if(!mesh->proxytype) {
403 result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
405 result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
406 freeaddrinfo(proxyai);
409 if(result == -1 && !sockinprogress(sockerrno)) {
410 logger(mesh, MESHLINK_ERROR, "Could not connect to %s: %s", outgoing->node->name, sockstrerror(sockerrno));
416 /* Now that there is a working socket, fill in the rest and register this connection. */
418 c->status.connecting = true;
419 c->status.initiator = true;
420 c->name = xstrdup(outgoing->node->name);
421 c->last_ping_time = mesh->loop.now.tv_sec;
423 connection_add(mesh, c);
425 io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ | IO_WRITE);
428 void reset_outgoing(outgoing_t *outgoing) {
430 if(outgoing->state == OUTGOING_RECENT || outgoing->state == OUTGOING_KNOWN) {
431 free_known_addresses(outgoing->ai);
433 freeaddrinfo(outgoing->ai);
438 outgoing->aip = NULL;
439 outgoing->state = OUTGOING_START;
442 void setup_outgoing_connection(meshlink_handle_t *mesh, outgoing_t *outgoing) {
443 timeout_del(&mesh->loop, &outgoing->ev);
445 if(outgoing->node->connection) {
446 logger(mesh, MESHLINK_INFO, "Already connected to %s", outgoing->node->name);
448 outgoing->node->connection->outgoing = outgoing;
452 reset_outgoing(outgoing);
454 if(outgoing->node->status.blacklisted) {
458 if(mesh->connection_try_cb) {
459 mesh->connection_try_cb(mesh, (meshlink_node_t *)outgoing->node);
462 do_outgoing_connection(mesh, outgoing);
465 /// Delayed close of a filedescriptor.
466 static void tarpit(meshlink_handle_t *mesh, int fd) {
471 if(mesh->pits[mesh->next_pit]) {
472 closesocket(mesh->pits[mesh->next_pit]);
475 mesh->pits[mesh->next_pit++] = fd;
477 if(mesh->next_pit >= (int)(sizeof mesh->pits / sizeof mesh->pits[0])) {
483 accept a new tcp connect and create a
486 void handle_new_meta_connection(event_loop_t *loop, void *data, int flags) {
488 meshlink_handle_t *mesh = loop->data;
489 listen_socket_t *l = data;
493 socklen_t len = sizeof(sa);
495 memset(&sa, 0, sizeof(sa));
497 fd = accept(l->tcp.fd, &sa.sa, &len);
500 if(errno == EINVAL) { // TODO: check if Windows agrees
501 event_loop_stop(loop);
505 logger(mesh, MESHLINK_ERROR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
511 /* Rate limit incoming connections to max_connection_burst/second. */
513 if(mesh->loop.now.tv_sec != mesh->connection_burst_time) {
514 mesh->connection_burst_time = mesh->loop.now.tv_sec;
515 mesh->connection_burst = 0;
518 if(mesh->connection_burst >= max_connection_burst) {
523 mesh->connection_burst++;
525 // Accept the new connection
527 c = new_connection();
528 c->name = xstrdup("<unknown>");
532 c->last_ping_time = mesh->loop.now.tv_sec;
534 char *hostname = sockaddr2hostname(&sa);
535 logger(mesh, MESHLINK_INFO, "Connection from %s", hostname);
538 io_add(&mesh->loop, &c->io, handle_meta_io, c, c->socket, IO_READ);
542 connection_add(mesh, c);
544 c->allow_request = ID;
548 static void free_outgoing(outgoing_t *outgoing) {
549 meshlink_handle_t *mesh = outgoing->node->mesh;
551 timeout_del(&mesh->loop, &outgoing->ev);
554 if(outgoing->state == OUTGOING_RECENT || outgoing->state == OUTGOING_KNOWN) {
555 free_known_addresses(outgoing->ai);
557 freeaddrinfo(outgoing->ai);
564 void init_outgoings(meshlink_handle_t *mesh) {
565 mesh->outgoings = list_alloc((list_action_t)free_outgoing);
568 void exit_outgoings(meshlink_handle_t *mesh) {
569 if(mesh->outgoings) {
570 list_delete_list(mesh->outgoings);
571 mesh->outgoings = NULL;