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"
24 #include "connection.h"
32 int maxoutbufsize = 0;
33 int mtu_info_interval = 5;
34 int udp_info_interval = 5;
36 bool send_termreq(connection_t *c) {
37 return send_request(c, "%d", TERMREQ);
40 bool termreq_h(connection_t *c, const char *request) {
46 bool send_ping(connection_t *c) {
47 c->status.pinged = true;
48 c->last_ping_time = now.tv_sec;
50 return send_request(c, "%d", PING);
53 bool ping_h(connection_t *c, const char *request) {
58 bool send_pong(connection_t *c) {
59 return send_request(c, "%d", PONG);
62 bool pong_h(connection_t *c, const char *request) {
64 c->status.pinged = false;
66 /* Successful connection, reset timeout if this is an outgoing connection. */
68 if(c->outgoing && c->outgoing->timeout) {
69 c->outgoing->timeout = 0;
70 reset_address_cache(c->outgoing->node->address_cache, &c->address);
76 /* Sending and receiving packets via TCP */
78 bool send_tcppacket(connection_t *c, const vpn_packet_t *packet) {
79 /* If there already is a lot of data in the outbuf buffer, discard this packet.
80 We use a very simple Random Early Drop algorithm. */
82 if(2.0 * c->outbuf.len / (float)maxoutbufsize - 1 > (float)rand() / (float)RAND_MAX) {
86 if(!send_request(c, "%d %d", PACKET, packet->len)) {
90 return send_meta(c, DATA(packet), packet->len);
93 bool tcppacket_h(connection_t *c, const char *request) {
96 if(sscanf(request, "%*d %hd", &len) != 1) {
97 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "PACKET", c->name,
102 /* Set reqlen to len, this will tell receive_meta() that a tcppacket is coming. */
109 bool send_sptps_tcppacket(connection_t *c, const void *packet, size_t len) {
110 /* If there already is a lot of data in the outbuf buffer, discard this packet.
111 We use a very simple Random Early Drop algorithm. */
113 if(2.0 * c->outbuf.len / (float)maxoutbufsize - 1 > (float)rand() / (float)RAND_MAX) {
117 if(!send_request(c, "%d %zu", SPTPS_PACKET, len)) {
121 send_meta_raw(c, packet, len);
125 bool sptps_tcppacket_h(connection_t *c, const char *request) {
128 if(sscanf(request, "%*d %hd", &len) != 1) {
129 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "SPTPS_PACKET", c->name,
134 /* Set sptpslen to len, this will tell receive_meta() that a SPTPS packet is coming. */
141 /* Transmitting UDP information */
143 bool send_udp_info(node_t *from, node_t *to) {
144 /* If there's a static relay in the path, there's no point in sending the message
145 farther than the static relay. */
146 to = (to->via == myself) ? to->nexthop : to->via;
149 logger(DEBUG_ALWAYS, LOG_ERR, "Something went wrong when selecting relay - possible fake UDP_INFO");
153 /* Skip cases where sending UDP info messages doesn't make sense.
154 This is done here in order to avoid repeating the same logic in multiple callsites. */
160 if(!to->status.reachable) {
169 struct timeval elapsed;
171 timersub(&now, &to->udp_info_sent, &elapsed);
173 if(elapsed.tv_sec < udp_info_interval) {
178 if((myself->options | from->options | to->options) & OPTION_TCPONLY) {
182 if((to->nexthop->options >> 24) < 5) {
186 char *from_address, *from_port;
187 /* If we're the originator, the address we use is irrelevant
188 because the first intermediate node will ignore it.
189 We use our local address as it somewhat makes sense
190 and it's simpler than introducing an encoding for "null" addresses anyway. */
191 sockaddr2str((from != myself) ? &from->address : &to->nexthop->connection->edge->local_address, &from_address, &from_port);
193 bool x = send_request(to->nexthop->connection, "%d %s %s %s %s", UDP_INFO, from->name, to->name, from_address, from_port);
199 to->udp_info_sent = now;
205 bool udp_info_h(connection_t *c, const char *request) {
206 char from_name[MAX_STRING_SIZE];
207 char to_name[MAX_STRING_SIZE];
208 char from_address[MAX_STRING_SIZE];
209 char from_port[MAX_STRING_SIZE];
211 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" "MAX_STRING, from_name, to_name, from_address, from_port) != 4) {
212 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "UDP_INFO", c->name, c->hostname);
216 if(!check_id(from_name) || !check_id(to_name)) {
217 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "UDP_INFO", c->name, c->hostname, "invalid name");
221 node_t *from = lookup_node(from_name);
224 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);
228 if(from != from->via) {
229 /* Not supposed to happen, as it means the message wandered past a static relay */
230 logger(DEBUG_PROTOCOL, LOG_WARNING, "Got UDP info message from %s (%s) which we can't reach directly", from->name, from->hostname);
234 /* If we have a direct edge to "from", we are in a better position
235 to guess its address than it is itself. */
236 if(!from->connection && !from->status.udp_confirmed) {
237 sockaddr_t from_addr = str2sockaddr(from_address, from_port);
239 if(sockaddrcmp(&from_addr, &from->address)) {
240 update_node_udp(from, &from_addr);
244 node_t *to = lookup_node(to_name);
247 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);
251 /* Send our own data (which could be what we just received) up the chain. */
253 return send_udp_info(from, to);
256 /* Transmitting MTU information */
258 bool send_mtu_info(node_t *from, node_t *to, int mtu) {
259 /* Skip cases where sending MTU info messages doesn't make sense.
260 This is done here in order to avoid repeating the same logic in multiple callsites. */
266 if(!to->status.reachable) {
275 struct timeval elapsed;
277 timersub(&now, &to->mtu_info_sent, &elapsed);
279 if(elapsed.tv_sec < mtu_info_interval) {
284 if((to->nexthop->options >> 24) < 6) {
288 /* We will send the passed-in MTU value, unless we believe ours is better. */
290 node_t *via = (from->via == myself) ? from->nexthop : from->via;
292 if(from->minmtu == from->maxmtu && from->via == myself) {
293 /* We have a direct measurement. Override the value entirely.
294 Note that we only do that if we are sitting as a static relay in the path;
295 otherwise, we can't guarantee packets will flow through us, and increasing
296 MTU could therefore end up being too optimistic. */
298 } else if(via->minmtu == via->maxmtu) {
299 /* Static relay. Ensure packets will make it through the entire relay path. */
300 mtu = MIN(mtu, via->minmtu);
301 } else if(via->nexthop->minmtu == via->nexthop->maxmtu) {
302 /* Dynamic relay. Ensure packets will make it through the entire relay path. */
303 mtu = MIN(mtu, via->nexthop->minmtu);
307 to->mtu_info_sent = now;
310 /* If none of the conditions above match in the steady state, it means we're using TCP,
311 so the MTU is irrelevant. That said, it is still important to honor the MTU that was passed in,
312 because other parts of the relay path might be able to use UDP, which means they care about the MTU. */
314 return send_request(to->nexthop->connection, "%d %s %s %d", MTU_INFO, from->name, to->name, mtu);
317 bool mtu_info_h(connection_t *c, const char *request) {
318 char from_name[MAX_STRING_SIZE];
319 char to_name[MAX_STRING_SIZE];
322 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" %d", from_name, to_name, &mtu) != 3) {
323 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "MTU_INFO", c->name, c->hostname);
328 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "MTU_INFO", c->name, c->hostname, "invalid MTU");
334 if(!check_id(from_name) || !check_id(to_name)) {
335 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "MTU_INFO", c->name, c->hostname, "invalid name");
339 node_t *from = lookup_node(from_name);
342 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);
346 /* If we don't know the current MTU for that node, use the one we received.
347 Even if we're about to make our own measurements, the value we got from downstream nodes should be pretty close
348 so it's a good idea to use it in the mean time. */
349 if(from->mtu != mtu && from->minmtu != from->maxmtu) {
350 logger(DEBUG_TRAFFIC, LOG_INFO, "Using provisional MTU %d for node %s (%s)", mtu, from->name, from->hostname);
354 node_t *to = lookup_node(to_name);
357 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);
361 /* Continue passing the MTU value (or a better one if we have it) up the chain. */
363 return send_mtu_info(from, to, mtu);