2 protocol_misc.c -- handle the meta-protocol, miscellaneous functions
3 Copyright (C) 1999-2005 Ivo Timmermans,
4 2000-2013 Guus Sliepen <guus@tinc-vpn.org>
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License along
17 with this program; if not, write to the Free Software Foundation, Inc.,
18 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
24 #include "connection.h"
34 #define MIN(x, y) (((x)<(y))?(x):(y))
37 int maxoutbufsize = 0;
38 int mtu_info_interval = 5;
39 int udp_info_interval = 5;
41 /* Status and error notification routines */
43 bool send_status(connection_t *c, int statusno, const char *statusstring) {
45 statusstring = "Status";
47 return send_request(c, "%d %d %s", STATUS, statusno, statusstring);
50 bool status_h(connection_t *c, const char *request) {
52 char statusstring[MAX_STRING_SIZE];
54 if(sscanf(request, "%*d %d " MAX_STRING, &statusno, statusstring) != 2) {
55 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "STATUS",
56 c->name, c->hostname);
60 logger(DEBUG_STATUS, LOG_NOTICE, "Status message from %s (%s): %d: %s",
61 c->name, c->hostname, statusno, statusstring);
66 bool send_error(connection_t *c, int err, const char *errstring) {
70 return send_request(c, "%d %d %s", ERROR, err, errstring);
73 bool error_h(connection_t *c, const char *request) {
75 char errorstring[MAX_STRING_SIZE];
77 if(sscanf(request, "%*d %d " MAX_STRING, &err, errorstring) != 2) {
78 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ERROR",
79 c->name, c->hostname);
83 logger(DEBUG_ERROR, LOG_NOTICE, "Error message from %s (%s): %d: %s",
84 c->name, c->hostname, err, errorstring);
89 bool send_termreq(connection_t *c) {
90 return send_request(c, "%d", TERMREQ);
93 bool termreq_h(connection_t *c, const char *request) {
97 bool send_ping(connection_t *c) {
98 c->status.pinged = true;
99 c->last_ping_time = now.tv_sec;
101 return send_request(c, "%d", PING);
104 bool ping_h(connection_t *c, const char *request) {
108 bool send_pong(connection_t *c) {
109 return send_request(c, "%d", PONG);
112 bool pong_h(connection_t *c, const char *request) {
113 c->status.pinged = false;
115 /* Succesful connection, reset timeout if this is an outgoing connection. */
118 c->outgoing->timeout = 0;
119 c->outgoing->cfg = NULL;
121 freeaddrinfo(c->outgoing->ai);
122 c->outgoing->ai = NULL;
123 c->outgoing->aip = NULL;
129 /* Sending and receiving packets via TCP */
131 bool send_tcppacket(connection_t *c, const vpn_packet_t *packet) {
132 /* If there already is a lot of data in the outbuf buffer, discard this packet.
133 We use a very simple Random Early Drop algorithm. */
135 if(2.0 * c->outbuf.len / (float)maxoutbufsize - 1 > (float)rand()/(float)RAND_MAX)
138 if(!send_request(c, "%d %d", PACKET, packet->len))
141 return send_meta(c, (char *)DATA(packet), packet->len);
144 bool tcppacket_h(connection_t *c, const char *request) {
147 if(sscanf(request, "%*d %hd", &len) != 1) {
148 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "PACKET", c->name,
153 /* Set reqlen to len, this will tell receive_meta() that a tcppacket is coming. */
160 bool send_sptps_tcppacket(connection_t *c, const char* packet, int len) {
161 /* If there already is a lot of data in the outbuf buffer, discard this packet.
162 We use a very simple Random Early Drop algorithm. */
164 if(2.0 * c->outbuf.len / (float)maxoutbufsize - 1 > (float)rand()/(float)RAND_MAX)
167 if(!send_request(c, "%d %d", SPTPS_PACKET, len))
170 send_meta_raw(c, packet, len);
174 bool sptps_tcppacket_h(connection_t *c, const char* request) {
177 if(sscanf(request, "%*d %hd", &len) != 1) {
178 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "SPTPS_PACKET", c->name,
183 /* Set sptpslen to len, this will tell receive_meta() that a SPTPS packet is coming. */
190 /* Transmitting UDP information */
192 bool send_udp_info(node_t *from, node_t *to) {
193 /* If there's a static relay in the path, there's no point in sending the message
194 farther than the static relay. */
195 to = (to->via == myself) ? to->nexthop : to->via;
198 logger(DEBUG_ALWAYS, LOG_ERR, "Something went wrong when selecting relay - possible fake UDP_INFO");
202 /* Skip cases where sending UDP info messages doesn't make sense.
203 This is done here in order to avoid repeating the same logic in multiple callsites. */
208 if(!to->status.reachable)
215 struct timeval elapsed;
216 timersub(&now, &to->udp_info_sent, &elapsed);
217 if(elapsed.tv_sec < udp_info_interval)
221 if((myself->options | from->options | to->options) & OPTION_TCPONLY)
224 if((to->nexthop->options >> 24) < 5)
227 char *from_address, *from_port;
228 /* If we're the originator, the address we use is irrelevant
229 because the first intermediate node will ignore it.
230 We use our local address as it somewhat makes sense
231 and it's simpler than introducing an encoding for "null" addresses anyway. */
232 sockaddr2str((from != myself) ? &from->address : &to->nexthop->connection->edge->local_address, &from_address, &from_port);
234 bool x = send_request(to->nexthop->connection, "%d %s %s %s %s", UDP_INFO, from->name, to->name, from_address, from_port);
240 to->udp_info_sent = now;
245 bool udp_info_h(connection_t *c, const char* request) {
246 char from_name[MAX_STRING_SIZE];
247 char to_name[MAX_STRING_SIZE];
248 char from_address[MAX_STRING_SIZE];
249 char from_port[MAX_STRING_SIZE];
251 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" "MAX_STRING, from_name, to_name, from_address, from_port) != 4) {
252 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "UDP_INFO", c->name, c->hostname);
256 if(!check_id(from_name) || !check_id(to_name)) {
257 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "UDP_INFO", c->name, c->hostname, "invalid name");
261 node_t *from = lookup_node(from_name);
263 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list", "UDP_INFO", c->name, c->hostname, from_name);
267 if(from != from->via) {
268 /* Not supposed to happen, as it means the message wandered past a static relay */
269 logger(DEBUG_PROTOCOL, LOG_WARNING, "Got UDP info message from %s (%s) which we can't reach directly", from->name, from->hostname);
273 /* If we have a direct edge to "from", we are in a better position
274 to guess its address than it is itself. */
275 if(!from->connection && !from->status.udp_confirmed) {
276 sockaddr_t from_addr = str2sockaddr(from_address, from_port);
277 if(sockaddrcmp(&from_addr, &from->address))
278 update_node_udp(from, &from_addr);
281 node_t *to = lookup_node(to_name);
283 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list", "UDP_INFO", c->name, c->hostname, to_name);
287 /* Send our own data (which could be what we just received) up the chain. */
289 return send_udp_info(from, to);
292 /* Transmitting MTU information */
294 bool send_mtu_info(node_t *from, node_t *to, int mtu) {
295 /* Skip cases where sending MTU info messages doesn't make sense.
296 This is done here in order to avoid repeating the same logic in multiple callsites. */
301 if(!to->status.reachable)
308 struct timeval elapsed;
309 timersub(&now, &to->mtu_info_sent, &elapsed);
310 if(elapsed.tv_sec < mtu_info_interval)
314 if((to->nexthop->options >> 24) < 6)
317 /* We will send the passed-in MTU value, unless we believe ours is better. */
319 node_t *via = (from->via == myself) ? from->nexthop : from->via;
320 if(from->minmtu == from->maxmtu && from->via == myself) {
321 /* We have a direct measurement. Override the value entirely.
322 Note that we only do that if we are sitting as a static relay in the path;
323 otherwise, we can't guarantee packets will flow through us, and increasing
324 MTU could therefore end up being too optimistic. */
326 } else if(via->minmtu == via->maxmtu) {
327 /* Static relay. Ensure packets will make it through the entire relay path. */
328 mtu = MIN(mtu, via->minmtu);
329 } else if(via->nexthop->minmtu == via->nexthop->maxmtu) {
330 /* Dynamic relay. Ensure packets will make it through the entire relay path. */
331 mtu = MIN(mtu, via->nexthop->minmtu);
335 to->mtu_info_sent = now;
337 /* If none of the conditions above match in the steady state, it means we're using TCP,
338 so the MTU is irrelevant. That said, it is still important to honor the MTU that was passed in,
339 because other parts of the relay path might be able to use UDP, which means they care about the MTU. */
341 return send_request(to->nexthop->connection, "%d %s %s %d", MTU_INFO, from->name, to->name, mtu);
344 bool mtu_info_h(connection_t *c, const char* request) {
345 char from_name[MAX_STRING_SIZE];
346 char to_name[MAX_STRING_SIZE];
349 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" %d", from_name, to_name, &mtu) != 3) {
350 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "MTU_INFO", c->name, c->hostname);
355 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "MTU_INFO", c->name, c->hostname, "invalid MTU");
361 if(!check_id(from_name) || !check_id(to_name)) {
362 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "MTU_INFO", c->name, c->hostname, "invalid name");
366 node_t *from = lookup_node(from_name);
368 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list", "MTU_INFO", c->name, c->hostname, from_name);
372 /* If we don't know the current MTU for that node, use the one we received.
373 Even if we're about to make our own measurements, the value we got from downstream nodes should be pretty close
374 so it's a good idea to use it in the mean time. */
375 if(from->mtu != mtu && from->minmtu != from->maxmtu) {
376 logger(DEBUG_TRAFFIC, LOG_INFO, "Using provisional MTU %d for node %s (%s)", mtu, from->name, from->hostname);
380 node_t *to = lookup_node(to_name);
382 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list", "MTU_INFO", c->name, c->hostname, to_name);
386 /* Continue passing the MTU value (or a better one if we have it) up the chain. */
388 return send_mtu_info(from, to, mtu);