2 protocol_key.c -- handle the meta-protocol, key exchange
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.
22 #include "connection.h"
24 #include "meshlink_internal.h"
35 static const int req_key_timeout = 2;
37 bool key_changed_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
41 char name[MAX_STRING_SIZE];
44 if(sscanf(request, "%*d %*x " MAX_STRING, name) != 1) {
45 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "KEY_CHANGED", c->name);
49 if(seen_request(mesh, request)) {
53 n = lookup_node(mesh, name);
56 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist", "KEY_CHANGED", c->name, name);
62 forward_request(mesh, c, NULL, request);
67 static bool send_initial_sptps_data(void *handle, uint8_t type, const void *data, size_t len) {
74 meshlink_handle_t *mesh = to->mesh;
76 if(!to->nexthop || !to->nexthop->connection) {
77 logger(mesh, MESHLINK_WARNING, "Cannot send SPTPS data to %s via %s", to->name, to->nexthop ? to->nexthop->name : to->name);
81 to->sptps.send_data = send_sptps_data;
82 char buf[len * 4 / 3 + 5];
83 b64encode(data, buf, len);
84 return send_request(mesh, to->nexthop->connection, NULL, "%d %s %s %d %s", REQ_KEY, mesh->self->name, to->name, REQ_KEY, buf);
87 bool send_canonical_address(meshlink_handle_t *mesh, node_t *to) {
88 if(!mesh->self->canonical_address) {
92 return send_request(mesh, to->nexthop->connection, NULL, "%d %s %s %d %s", REQ_KEY, mesh->self->name, to->name, REQ_CANONICAL, mesh->self->canonical_address);
95 bool send_req_key(meshlink_handle_t *mesh, node_t *to) {
96 if(!node_read_public_key(mesh, to)) {
97 logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", to->name);
99 if(!to->nexthop || !to->nexthop->connection) {
100 logger(mesh, MESHLINK_WARNING, "Cannot send REQ_PUBKEY to %s via %s", to->name, to->nexthop ? to->nexthop->name : to->name);
104 char *pubkey = ecdsa_get_base64_public_key(mesh->private_key);
105 send_request(mesh, to->nexthop->connection, NULL, "%d %s %s %d %s", REQ_KEY, mesh->self->name, to->name, REQ_PUBKEY, pubkey);
110 if(to->sptps.label) {
111 logger(mesh, MESHLINK_DEBUG, "send_req_key(%s) called while sptps->label != NULL!", to->name);
114 /* Send our canonical address to help with UDP hole punching */
115 send_canonical_address(mesh, to);
117 char label[sizeof(meshlink_udp_label) + strlen(mesh->self->name) + strlen(to->name) + 2];
118 snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, mesh->self->name, to->name);
119 sptps_stop(&to->sptps);
120 to->status.validkey = false;
121 to->status.waitingforkey = true;
122 to->last_req_key = mesh->loop.now.tv_sec;
123 return sptps_start(&to->sptps, to, true, true, mesh->private_key, to->ecdsa, label, sizeof(label) - 1, send_initial_sptps_data, receive_sptps_record);
126 /* REQ_KEY is overloaded to allow arbitrary requests to be routed between two nodes. */
128 static bool req_key_ext_h(meshlink_handle_t *mesh, connection_t *c, const char *request, node_t *from, int reqno) {
131 if(!from->nexthop || !from->nexthop->connection) {
132 logger(mesh, MESHLINK_WARNING, "Cannot answer REQ_KEY from %s via %s", from->name, from->nexthop ? from->nexthop->name : from->name);
138 char *pubkey = ecdsa_get_base64_public_key(mesh->private_key);
140 if(!node_read_public_key(mesh, from)) {
141 char hiskey[MAX_STRING_SIZE];
143 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, hiskey) == 1) {
144 from->ecdsa = ecdsa_set_base64_public_key(hiskey);
147 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_PUBKEY", from->name, "invalid pubkey");
151 logger(mesh, MESHLINK_INFO, "Learned ECDSA public key from %s", from->name);
152 from->status.dirty = true;
154 if(!node_write_config(mesh, from, true)) {
160 send_request(mesh, from->nexthop->connection, NULL, "%d %s %s %d %s", REQ_KEY, mesh->self->name, from->name, ANS_PUBKEY, pubkey);
166 if(node_read_public_key(mesh, from)) {
167 logger(mesh, MESHLINK_WARNING, "Got ANS_PUBKEY from %s even though we already have his pubkey", from->name);
171 char pubkey[MAX_STRING_SIZE];
173 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !(from->ecdsa = ecdsa_set_base64_public_key(pubkey))) {
174 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_PUBKEY", from->name, "invalid pubkey");
178 logger(mesh, MESHLINK_INFO, "Learned ECDSA public key from %s", from->name);
179 from->status.dirty = true;
181 if(!node_write_config(mesh, from, true)) {
185 /* If we are trying to form an outgoing connection to this node, retry immediately */
186 for list_each(outgoing_t, outgoing, mesh->outgoings) {
187 if(outgoing->node == from && outgoing->ev.cb) {
188 outgoing->timeout = 0;
189 timeout_set(&mesh->loop, &outgoing->ev, &(struct timespec) {
195 /* Also reset any UTCP timers */
196 utcp_reset_timers(from->utcp);
202 if(!node_read_public_key(mesh, from)) {
203 logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", from->name);
204 send_request(mesh, from->nexthop->connection, NULL, "%d %s %s %d", REQ_KEY, mesh->self->name, from->name, REQ_PUBKEY);
208 if(from->sptps.label) {
209 logger(mesh, MESHLINK_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name);
211 if(mesh->loop.now.tv_sec < from->last_req_key + req_key_timeout && strcmp(mesh->self->name, from->name) < 0) {
212 logger(mesh, MESHLINK_DEBUG, "Ignoring REQ_KEY from %s.", from->name);
217 char buf[MAX_STRING_SIZE];
220 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
221 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS_START", from->name, "invalid SPTPS data");
225 char label[sizeof(meshlink_udp_label) + strlen(from->name) + strlen(mesh->self->name) + 2];
226 snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, from->name, mesh->self->name);
227 sptps_stop(&from->sptps);
228 from->status.validkey = false;
229 from->status.waitingforkey = true;
230 from->last_req_key = mesh->loop.now.tv_sec;
232 /* Send our canonical address to help with UDP hole punching */
233 send_canonical_address(mesh, from);
235 if(!sptps_start(&from->sptps, from, false, true, mesh->private_key, from->ecdsa, label, sizeof(label) - 1, send_sptps_data, receive_sptps_record)) {
236 logger(mesh, MESHLINK_ERROR, "Could not start SPTPS session with %s: %s", from->name, strerror(errno));
240 if(!sptps_receive_data(&from->sptps, buf, len)) {
241 logger(mesh, MESHLINK_ERROR, "Could not process SPTPS data from %s: %s", from->name, strerror(errno));
249 if(!from->status.validkey) {
250 logger(mesh, MESHLINK_ERROR, "Got REQ_SPTPS from %s but we don't have a valid key yet", from->name);
254 char buf[MAX_STRING_SIZE];
257 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
258 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS", from->name, "invalid SPTPS data");
262 if(!sptps_receive_data(&from->sptps, buf, len)) {
263 logger(mesh, MESHLINK_ERROR, "Could not process SPTPS data from %s: %s", from->name, strerror(errno));
270 case REQ_CANONICAL: {
271 char host[MAX_STRING_SIZE];
272 char port[MAX_STRING_SIZE];
274 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING " " MAX_STRING, host, port) != 2) {
275 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_CANONICAL", from->name, "invalid canonical address");
279 char *canonical_address;
280 xasprintf(&canonical_address, "%s %s", host, port);
282 if(mesh->log_level <= MESHLINK_DEBUG && (!from->canonical_address || strcmp(from->canonical_address, canonical_address))) {
283 logger(mesh, MESHLINK_DEBUG, "Updating canonical address of %s to %s", from->name, canonical_address);
286 free(from->canonical_address);
287 from->canonical_address = canonical_address;
292 logger(mesh, MESHLINK_ERROR, "Unknown extended REQ_KEY request from %s: %s", from->name, request);
297 bool req_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
301 char from_name[MAX_STRING_SIZE];
302 char to_name[MAX_STRING_SIZE];
306 if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
307 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "REQ_KEY", c->name);
311 if(!check_id(from_name) || !check_id(to_name)) {
312 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_KEY", c->name, "invalid name");
316 from = lookup_node(mesh, from_name);
319 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
320 "REQ_KEY", c->name, from_name);
324 to = lookup_node(mesh, to_name);
327 logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
328 "REQ_KEY", c->name, to_name);
332 /* Check if this key request is for us */
334 if(to == mesh->self) { /* Yes */
335 /* Is this an extended REQ_KEY message? */
337 return req_key_ext_h(mesh, c, request, from, reqno);
340 /* This should never happen. Ignore it, unless it came directly from the connected peer, in which case we disconnect. */
341 return from->connection != c;
343 if(!to->status.reachable || !to->nexthop || !to->nexthop->connection) {
344 logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
345 "REQ_KEY", c->name, to_name);
349 size_t len = strlen(request);
350 from->in_forward += len + SPTPS_OVERHEAD;
351 to->out_forward += len + SPTPS_OVERHEAD;
353 send_request(mesh, to->nexthop->connection, NULL, "%s", request);
359 bool ans_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
363 char from_name[MAX_STRING_SIZE];
364 char to_name[MAX_STRING_SIZE];
365 char key[MAX_STRING_SIZE];
366 char address[MAX_STRING_SIZE] = "";
367 char port[MAX_STRING_SIZE] = "";
368 int cipher, digest, maclength, compression;
371 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
372 from_name, to_name, key, &cipher, &digest, &maclength,
373 &compression, address, port) < 7) {
374 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "ANS_KEY", c->name);
378 if(!check_id(from_name) || !check_id(to_name)) {
379 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_KEY", c->name, "invalid name");
383 from = lookup_node(mesh, from_name);
386 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
387 "ANS_KEY", c->name, from_name);
391 to = lookup_node(mesh, to_name);
394 logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
395 "ANS_KEY", c->name, to_name);
399 /* Forward it if necessary */
401 if(to != mesh->self) {
402 if(!to->status.reachable) {
403 logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
404 "ANS_KEY", c->name, to_name);
409 logger(mesh, MESHLINK_WARNING, "Got %s from %s from %s to %s",
410 "ANS_KEY", c->name, from_name, to_name);
414 if(!to->nexthop || !to->nexthop->connection) {
415 logger(mesh, MESHLINK_WARNING, "Cannot forward ANS_KEY to %s via %s", to->name, to->nexthop ? to->nexthop->name : to->name);
419 /* TODO: find a good way to avoid the use of strlen() */
420 size_t len = strlen(request);
421 from->in_forward += len + SPTPS_OVERHEAD;
422 to->out_forward += len + SPTPS_OVERHEAD;
424 /* Append the known UDP address of the from node, if we have a confirmed one */
425 if(!*address && from->status.udp_confirmed && from->address.sa.sa_family != AF_UNSPEC) {
426 char *reflexive_address, *reflexive_port;
427 logger(mesh, MESHLINK_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name);
428 sockaddr2str(&from->address, &reflexive_address, &reflexive_port);
429 send_request(mesh, to->nexthop->connection, NULL, "%s %s %s", request, reflexive_address, reflexive_port);
430 free(reflexive_address);
431 free(reflexive_port);
435 return send_request(mesh, to->nexthop->connection, NULL, "%s", request);
438 /* Is this an ANS_KEY informing us of our own reflexive UDP address? */
440 if(from == mesh->self) {
441 if(*key == '.' && *address && *port) {
442 logger(mesh, MESHLINK_DEBUG, "Learned our own reflexive UDP address from %s: %s port %s", c->name, address, port);
444 /* Inform all other nodes we want to communicate with and which are reachable via this connection */
445 for splay_each(node_t, n, mesh->nodes) {
446 if(n->nexthop != c->node) {
450 if(n->status.udp_confirmed) {
454 if(!n->status.waitingforkey && !n->status.validkey) {
458 if(!n->nexthop->connection) {
462 logger(mesh, MESHLINK_DEBUG, "Forwarding our own reflexive UDP address to %s", n->name);
463 send_request(mesh, c, NULL, "%d %s %s . -1 -1 -1 0 %s %s", ANS_KEY, mesh->self->name, n->name, address, port);
466 logger(mesh, MESHLINK_WARNING, "Got %s from %s from %s to %s",
467 "ANS_KEY", c->name, from_name, to_name);
473 /* Process SPTPS data if present */
476 /* Don't use key material until every check has passed. */
477 from->status.validkey = false;
479 /* Compression is not supported. */
480 if(compression != 0) {
481 logger(mesh, MESHLINK_ERROR, "Node %s uses bogus compression level!", from->name);
485 char buf[strlen(key)];
486 int len = b64decode(key, buf, strlen(key));
488 if(!len || !sptps_receive_data(&from->sptps, buf, len)) {
489 logger(mesh, MESHLINK_ERROR, "Error processing SPTPS data from %s", from->name);
493 if(from->status.validkey) {
494 if(*address && *port) {
495 logger(mesh, MESHLINK_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
496 sockaddr_t sa = str2sockaddr(address, port);
497 update_node_udp(mesh, from, &sa);
500 keepalive(mesh, from, true);