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.
23 #include "address_cache.h"
25 #include "connection.h"
35 #define MIN(x, y) (((x)<(y))?(x):(y))
38 int maxoutbufsize = 0;
39 int mtu_info_interval = 5;
40 int udp_info_interval = 5;
42 bool send_termreq(connection_t *c) {
43 return send_request(c, "%d", TERMREQ);
46 bool termreq_h(connection_t *c, const char *request) {
50 bool send_ping(connection_t *c) {
51 c->status.pinged = true;
52 c->last_ping_time = now.tv_sec;
54 return send_request(c, "%d", PING);
57 bool ping_h(connection_t *c, const char *request) {
61 bool send_pong(connection_t *c) {
62 return send_request(c, "%d", PONG);
65 bool pong_h(connection_t *c, const char *request) {
66 c->status.pinged = false;
68 /* Successful connection, reset timeout if this is an outgoing connection. */
71 c->outgoing->timeout = 0;
72 reset_address_cache(c->outgoing->address_cache, &c->address);
78 /* Sending and receiving packets via TCP */
80 bool send_tcppacket(connection_t *c, const vpn_packet_t *packet) {
81 /* If there already is a lot of data in the outbuf buffer, discard this packet.
82 We use a very simple Random Early Drop algorithm. */
84 if(2.0 * c->outbuf.len / (float)maxoutbufsize - 1 > (float)rand() / (float)RAND_MAX) {
88 if(!send_request(c, "%d %d", PACKET, packet->len)) {
92 return send_meta(c, (char *)DATA(packet), packet->len);
95 bool tcppacket_h(connection_t *c, const char *request) {
98 if(sscanf(request, "%*d %hd", &len) != 1) {
99 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "PACKET", c->name,
104 /* Set reqlen to len, this will tell receive_meta() that a tcppacket is coming. */
111 bool send_sptps_tcppacket(connection_t *c, const char *packet, int len) {
112 /* If there already is a lot of data in the outbuf buffer, discard this packet.
113 We use a very simple Random Early Drop algorithm. */
115 if(2.0 * c->outbuf.len / (float)maxoutbufsize - 1 > (float)rand() / (float)RAND_MAX) {
119 if(!send_request(c, "%d %d", SPTPS_PACKET, len)) {
123 send_meta_raw(c, packet, len);
127 bool sptps_tcppacket_h(connection_t *c, const char *request) {
130 if(sscanf(request, "%*d %hd", &len) != 1) {
131 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "SPTPS_PACKET", c->name,
136 /* Set sptpslen to len, this will tell receive_meta() that a SPTPS packet is coming. */
143 /* Transmitting UDP information */
145 bool send_udp_info(node_t *from, node_t *to) {
146 /* If there's a static relay in the path, there's no point in sending the message
147 farther than the static relay. */
148 to = (to->via == myself) ? to->nexthop : to->via;
151 logger(DEBUG_ALWAYS, LOG_ERR, "Something went wrong when selecting relay - possible fake UDP_INFO");
155 /* Skip cases where sending UDP info messages doesn't make sense.
156 This is done here in order to avoid repeating the same logic in multiple callsites. */
162 if(!to->status.reachable) {
171 struct timeval elapsed;
173 timersub(&now, &to->udp_info_sent, &elapsed);
175 if(elapsed.tv_sec < udp_info_interval) {
180 if((myself->options | from->options | to->options) & OPTION_TCPONLY) {
184 if((to->nexthop->options >> 24) < 5) {
188 char *from_address, *from_port;
189 /* If we're the originator, the address we use is irrelevant
190 because the first intermediate node will ignore it.
191 We use our local address as it somewhat makes sense
192 and it's simpler than introducing an encoding for "null" addresses anyway. */
193 sockaddr2str((from != myself) ? &from->address : &to->nexthop->connection->edge->local_address, &from_address, &from_port);
195 bool x = send_request(to->nexthop->connection, "%d %s %s %s %s", UDP_INFO, from->name, to->name, from_address, from_port);
201 to->udp_info_sent = now;
207 bool udp_info_h(connection_t *c, const char *request) {
208 char from_name[MAX_STRING_SIZE];
209 char to_name[MAX_STRING_SIZE];
210 char from_address[MAX_STRING_SIZE];
211 char from_port[MAX_STRING_SIZE];
213 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" "MAX_STRING, from_name, to_name, from_address, from_port) != 4) {
214 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "UDP_INFO", c->name, c->hostname);
218 if(!check_id(from_name) || !check_id(to_name)) {
219 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "UDP_INFO", c->name, c->hostname, "invalid name");
223 node_t *from = lookup_node(from_name);
226 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);
230 if(from != from->via) {
231 /* Not supposed to happen, as it means the message wandered past a static relay */
232 logger(DEBUG_PROTOCOL, LOG_WARNING, "Got UDP info message from %s (%s) which we can't reach directly", from->name, from->hostname);
236 /* If we have a direct edge to "from", we are in a better position
237 to guess its address than it is itself. */
238 if(!from->connection && !from->status.udp_confirmed) {
239 sockaddr_t from_addr = str2sockaddr(from_address, from_port);
241 if(sockaddrcmp(&from_addr, &from->address)) {
242 update_node_udp(from, &from_addr);
246 node_t *to = lookup_node(to_name);
249 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);
253 /* Send our own data (which could be what we just received) up the chain. */
255 return send_udp_info(from, to);
258 /* Transmitting MTU information */
260 bool send_mtu_info(node_t *from, node_t *to, int mtu) {
261 /* Skip cases where sending MTU info messages doesn't make sense.
262 This is done here in order to avoid repeating the same logic in multiple callsites. */
268 if(!to->status.reachable) {
277 struct timeval elapsed;
279 timersub(&now, &to->mtu_info_sent, &elapsed);
281 if(elapsed.tv_sec < mtu_info_interval) {
286 if((to->nexthop->options >> 24) < 6) {
290 /* We will send the passed-in MTU value, unless we believe ours is better. */
292 node_t *via = (from->via == myself) ? from->nexthop : from->via;
294 if(from->minmtu == from->maxmtu && from->via == myself) {
295 /* We have a direct measurement. Override the value entirely.
296 Note that we only do that if we are sitting as a static relay in the path;
297 otherwise, we can't guarantee packets will flow through us, and increasing
298 MTU could therefore end up being too optimistic. */
300 } else if(via->minmtu == via->maxmtu) {
301 /* Static relay. Ensure packets will make it through the entire relay path. */
302 mtu = MIN(mtu, via->minmtu);
303 } else if(via->nexthop->minmtu == via->nexthop->maxmtu) {
304 /* Dynamic relay. Ensure packets will make it through the entire relay path. */
305 mtu = MIN(mtu, via->nexthop->minmtu);
309 to->mtu_info_sent = now;
312 /* If none of the conditions above match in the steady state, it means we're using TCP,
313 so the MTU is irrelevant. That said, it is still important to honor the MTU that was passed in,
314 because other parts of the relay path might be able to use UDP, which means they care about the MTU. */
316 return send_request(to->nexthop->connection, "%d %s %s %d", MTU_INFO, from->name, to->name, mtu);
319 bool mtu_info_h(connection_t *c, const char *request) {
320 char from_name[MAX_STRING_SIZE];
321 char to_name[MAX_STRING_SIZE];
324 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" %d", from_name, to_name, &mtu) != 3) {
325 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "MTU_INFO", c->name, c->hostname);
330 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "MTU_INFO", c->name, c->hostname, "invalid MTU");
336 if(!check_id(from_name) || !check_id(to_name)) {
337 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "MTU_INFO", c->name, c->hostname, "invalid name");
341 node_t *from = lookup_node(from_name);
344 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);
348 /* If we don't know the current MTU for that node, use the one we received.
349 Even if we're about to make our own measurements, the value we got from downstream nodes should be pretty close
350 so it's a good idea to use it in the mean time. */
351 if(from->mtu != mtu && from->minmtu != from->maxmtu) {
352 logger(DEBUG_TRAFFIC, LOG_INFO, "Using provisional MTU %d for node %s (%s)", mtu, from->name, from->hostname);
356 node_t *to = lookup_node(to_name);
359 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);
363 /* Continue passing the MTU value (or a better one if we have it) up the chain. */
365 return send_mtu_info(from, to, mtu);