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"
33 int maxoutbufsize = 0;
35 /* Status and error notification routines */
37 bool send_status(connection_t *c, int statusno, const char *statusstring) {
39 statusstring = "Status";
41 return send_request(c, "%d %d %s", STATUS, statusno, statusstring);
44 bool status_h(connection_t *c, const char *request) {
46 char statusstring[MAX_STRING_SIZE];
48 if(sscanf(request, "%*d %d " MAX_STRING, &statusno, statusstring) != 2) {
49 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "STATUS",
50 c->name, c->hostname);
54 logger(DEBUG_STATUS, LOG_NOTICE, "Status message from %s (%s): %d: %s",
55 c->name, c->hostname, statusno, statusstring);
60 bool send_error(connection_t *c, int err, const char *errstring) {
64 return send_request(c, "%d %d %s", ERROR, err, errstring);
67 bool error_h(connection_t *c, const char *request) {
69 char errorstring[MAX_STRING_SIZE];
71 if(sscanf(request, "%*d %d " MAX_STRING, &err, errorstring) != 2) {
72 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ERROR",
73 c->name, c->hostname);
77 logger(DEBUG_ERROR, LOG_NOTICE, "Error message from %s (%s): %d: %s",
78 c->name, c->hostname, err, errorstring);
83 bool send_termreq(connection_t *c) {
84 return send_request(c, "%d", TERMREQ);
87 bool termreq_h(connection_t *c, const char *request) {
91 bool send_ping(connection_t *c) {
92 c->status.pinged = true;
93 c->last_ping_time = now.tv_sec;
95 return send_request(c, "%d", PING);
98 bool ping_h(connection_t *c, const char *request) {
102 bool send_pong(connection_t *c) {
103 return send_request(c, "%d", PONG);
106 bool pong_h(connection_t *c, const char *request) {
107 c->status.pinged = false;
109 /* Succesful connection, reset timeout if this is an outgoing connection. */
112 c->outgoing->timeout = 0;
113 c->outgoing->cfg = NULL;
115 freeaddrinfo(c->outgoing->ai);
116 c->outgoing->ai = NULL;
117 c->outgoing->aip = NULL;
123 /* Sending and receiving packets via TCP */
125 bool send_tcppacket(connection_t *c, const vpn_packet_t *packet) {
126 /* If there already is a lot of data in the outbuf buffer, discard this packet.
127 We use a very simple Random Early Drop algorithm. */
129 if(2.0 * c->outbuf.len / (float)maxoutbufsize - 1 > (float)rand()/(float)RAND_MAX)
132 if(!send_request(c, "%d %hd", PACKET, packet->len))
135 return send_meta(c, (char *)DATA(packet), packet->len);
138 bool tcppacket_h(connection_t *c, const char *request) {
141 if(sscanf(request, "%*d %hd", &len) != 1) {
142 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "PACKET", c->name,
147 /* Set reqlen to len, this will tell receive_meta() that a tcppacket is coming. */
154 /* Transmitting UDP information */
156 bool send_udp_info(node_t *from, node_t *to) {
157 /* If there's a static relay in the path, there's no point in sending the message
158 farther than the static relay. */
159 to = (to->via == myself) ? to->nexthop : to->via;
161 /* Skip cases where sending UDP info messages doesn't make sense.
162 This is done here in order to avoid repeating the same logic in multiple callsites. */
167 if(!to->status.reachable)
170 if(from == myself && to->connection)
173 if((myself->options | from->options | to->options) & OPTION_TCPONLY)
176 if((to->nexthop->options >> 24) < 5)
179 char *from_address, *from_port;
180 /* If we're the originator, the address we use is irrelevant
181 because the first intermediate node will ignore it.
182 We use our local address as it somewhat makes sense
183 and it's simpler than introducing an encoding for "null" addresses anyway. */
184 sockaddr2str((from != myself) ? &from->address : &to->nexthop->connection->edge->local_address, &from_address, &from_port);
186 bool x = send_request(to->nexthop->connection, "%d %s %s %s %s", UDP_INFO, from->name, to->name, from_address, from_port);
194 bool udp_info_h(connection_t *c, const char* request) {
195 char from_name[MAX_STRING_SIZE];
196 char to_name[MAX_STRING_SIZE];
197 char from_address[MAX_STRING_SIZE];
198 char from_port[MAX_STRING_SIZE];
200 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" "MAX_STRING, from_name, to_name, from_address, from_port) != 4) {
201 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "UDP_INFO", c->name, c->hostname);
205 if(!check_id(from_name) || !check_id(to_name)) {
206 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "UDP_INFO", c->name, c->hostname, "invalid name");
210 node_t *from = lookup_node(from_name);
212 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);
216 if(from != from->via) {
217 /* Not supposed to happen, as it means the message wandered past a static relay */
218 logger(DEBUG_PROTOCOL, LOG_WARNING, "Got UDP info message from %s (%s) which we can't reach directly", from->name, from->hostname);
222 /* If we have a direct edge to "from", we are in a better position
223 to guess its address than it is itself. */
224 if(!from->connection && !from->status.udp_confirmed) {
225 sockaddr_t from_addr = str2sockaddr(from_address, from_port);
226 if(sockaddrcmp(&from_addr, &from->address))
227 update_node_udp(from, &from_addr);
230 node_t *to = lookup_node(to_name);
232 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);
236 /* Send our own data (which could be what we just received) up the chain. */
238 return send_udp_info(from, to);
241 /* Transmitting MTU information */
243 bool send_mtu_info(node_t *from, node_t *to, int mtu) {
244 /* Skip cases where sending MTU info messages doesn't make sense.
245 This is done here in order to avoid repeating the same logic in multiple callsites. */
250 if(!to->status.reachable)
253 if(from == myself && to->connection)
256 if((to->nexthop->options >> 24) < 6)
259 /* We will send the passed-in MTU value, unless we believe ours is better. */
261 node_t *via = (from->via == myself) ? from->nexthop : from->via;
262 if(from->minmtu == from->maxmtu && from->via == myself) {
263 /* We have a direct measurement. Override the value entirely.
264 Note that we only do that if we are sitting as a static relay in the path;
265 otherwise, we can't guarantee packets will flow through us, and increasing
266 MTU could therefore end up being too optimistic. */
268 } else if(via->minmtu == via->maxmtu) {
269 /* Static relay. Ensure packets will make it through the entire relay path. */
270 mtu = MIN(mtu, via->minmtu);
271 } else if(via->nexthop->minmtu == via->nexthop->maxmtu) {
272 /* Dynamic relay. Ensure packets will make it through the entire relay path. */
273 mtu = MIN(mtu, via->nexthop->minmtu);
276 /* If none of the conditions above match in the steady state, it means we're using TCP,
277 so the MTU is irrelevant. That said, it is still important to honor the MTU that was passed in,
278 because other parts of the relay path might be able to use UDP, which means they care about the MTU. */
280 return send_request(to->nexthop->connection, "%d %s %s %d", MTU_INFO, from->name, to->name, mtu);
283 bool mtu_info_h(connection_t *c, const char* request) {
284 char from_name[MAX_STRING_SIZE];
285 char to_name[MAX_STRING_SIZE];
288 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" %d", from_name, to_name, &mtu) != 3) {
289 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "MTU_INFO", c->name, c->hostname);
294 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "MTU_INFO", c->name, c->hostname, "invalid MTU");
300 if(!check_id(from_name) || !check_id(to_name)) {
301 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "MTU_INFO", c->name, c->hostname, "invalid name");
305 node_t *from = lookup_node(from_name);
307 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);
311 /* If we don't know the current MTU for that node, use the one we received.
312 Even if we're about to make our own measurements, the value we got from downstream nodes should be pretty close
313 so it's a good idea to use it in the mean time. */
314 if(from->mtu != mtu && from->minmtu != from->maxmtu) {
315 logger(DEBUG_TRAFFIC, LOG_INFO, "Using provisional MTU %d for node %s (%s)", mtu, from->name, from->hostname);
319 node_t *to = lookup_node(to_name);
321 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);
325 /* Continue passing the MTU value (or a better one if we have it) up the chain. */
327 return send_mtu_info(from, to, mtu);