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"
34 static const int req_key_timeout = 2;
36 bool key_changed_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
40 char name[MAX_STRING_SIZE];
43 if(sscanf(request, "%*d %*x " MAX_STRING, name) != 1) {
44 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "KEY_CHANGED", c->name);
48 if(seen_request(mesh, request)) {
52 n = lookup_node(mesh, name);
55 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist", "KEY_CHANGED", c->name, name);
61 forward_request(mesh, c, NULL, request);
66 static bool send_initial_sptps_data(void *handle, uint8_t type, const void *data, size_t len) {
73 meshlink_handle_t *mesh = to->mesh;
75 if(!to->nexthop || !to->nexthop->connection) {
76 logger(mesh, MESHLINK_WARNING, "Cannot send SPTPS data to %s via %s", to->name, to->nexthop ? to->nexthop->name : to->name);
80 to->sptps.send_data = send_sptps_data;
81 char buf[len * 4 / 3 + 5];
82 b64encode(data, buf, len);
83 return send_request(mesh, to->nexthop->connection, NULL, "%d %s %s %d %s", REQ_KEY, mesh->self->name, to->name, REQ_KEY, buf);
86 bool send_canonical_address(meshlink_handle_t *mesh, node_t *to) {
87 if(!mesh->self->canonical_address) {
91 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);
94 bool send_req_key(meshlink_handle_t *mesh, node_t *to) {
95 if(!node_read_public_key(mesh, to)) {
96 logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", to->name);
98 if(!to->nexthop || !to->nexthop->connection) {
99 logger(mesh, MESHLINK_WARNING, "Cannot send REQ_PUBKEY to %s via %s", to->name, to->nexthop ? to->nexthop->name : to->name);
103 char *pubkey = ecdsa_get_base64_public_key(mesh->private_key);
104 send_request(mesh, to->nexthop->connection, NULL, "%d %s %s %d %s", REQ_KEY, mesh->self->name, to->name, REQ_PUBKEY, pubkey);
109 if(to->sptps.label) {
110 logger(mesh, MESHLINK_DEBUG, "send_req_key(%s) called while sptps->label != NULL!", to->name);
113 /* Send our canonical address to help with UDP hole punching */
114 send_canonical_address(mesh, to);
116 char label[sizeof(meshlink_udp_label) + strlen(mesh->self->name) + strlen(to->name) + 2];
117 snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, mesh->self->name, to->name);
118 sptps_stop(&to->sptps);
119 to->status.validkey = false;
120 to->status.waitingforkey = true;
121 to->last_req_key = mesh->loop.now.tv_sec;
122 return sptps_start(&to->sptps, to, true, true, mesh->private_key, to->ecdsa, label, sizeof(label) - 1, send_initial_sptps_data, receive_sptps_record);
125 /* REQ_KEY is overloaded to allow arbitrary requests to be routed between two nodes. */
127 static bool req_key_ext_h(meshlink_handle_t *mesh, connection_t *c, const char *request, node_t *from, int reqno) {
130 if(!from->nexthop || !from->nexthop->connection) {
131 logger(mesh, MESHLINK_WARNING, "Cannot answer REQ_KEY from %s via %s", from->name, from->nexthop ? from->nexthop->name : from->name);
137 char *pubkey = ecdsa_get_base64_public_key(mesh->private_key);
139 if(!node_read_public_key(mesh, from)) {
140 char hiskey[MAX_STRING_SIZE];
142 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, hiskey) == 1) {
143 from->ecdsa = ecdsa_set_base64_public_key(hiskey);
146 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_PUBKEY", from->name, "invalid pubkey");
150 logger(mesh, MESHLINK_INFO, "Learned ECDSA public key from %s", from->name);
151 from->status.dirty = true;
153 if(!node_write_config(mesh, from, true)) {
159 send_request(mesh, from->nexthop->connection, NULL, "%d %s %s %d %s", REQ_KEY, mesh->self->name, from->name, ANS_PUBKEY, pubkey);
165 if(node_read_public_key(mesh, from)) {
166 logger(mesh, MESHLINK_WARNING, "Got ANS_PUBKEY from %s even though we already have his pubkey", from->name);
170 char pubkey[MAX_STRING_SIZE];
172 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !(from->ecdsa = ecdsa_set_base64_public_key(pubkey))) {
173 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_PUBKEY", from->name, "invalid pubkey");
177 logger(mesh, MESHLINK_INFO, "Learned ECDSA public key from %s", from->name);
178 from->status.dirty = true;
180 if(!node_write_config(mesh, from, true)) {
184 /* If we are trying to form an outgoing connection to this node, retry immediately */
185 for list_each(outgoing_t, outgoing, mesh->outgoings) {
186 if(outgoing->node == from && outgoing->ev.cb) {
187 outgoing->timeout = 0;
188 timeout_set(&mesh->loop, &outgoing->ev, &(struct timespec) {
194 /* Also reset any UTCP timers */
195 utcp_reset_timers(from->utcp);
201 if(!node_read_public_key(mesh, from)) {
202 logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", from->name);
203 send_request(mesh, from->nexthop->connection, NULL, "%d %s %s %d", REQ_KEY, mesh->self->name, from->name, REQ_PUBKEY);
207 if(from->sptps.label) {
208 logger(mesh, MESHLINK_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name);
210 if(mesh->loop.now.tv_sec < from->last_req_key + req_key_timeout && strcmp(mesh->self->name, from->name) < 0) {
211 logger(mesh, MESHLINK_DEBUG, "Ignoring REQ_KEY from %s.", from->name);
216 char buf[MAX_STRING_SIZE];
219 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
220 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS_START", from->name, "invalid SPTPS data");
224 char label[sizeof(meshlink_udp_label) + strlen(from->name) + strlen(mesh->self->name) + 2];
225 snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, from->name, mesh->self->name);
226 sptps_stop(&from->sptps);
227 from->status.validkey = false;
228 from->status.waitingforkey = true;
229 from->last_req_key = mesh->loop.now.tv_sec;
231 /* Send our canonical address to help with UDP hole punching */
232 send_canonical_address(mesh, from);
234 if(!sptps_start(&from->sptps, from, false, true, mesh->private_key, from->ecdsa, label, sizeof(label) - 1, send_sptps_data, receive_sptps_record)) {
235 logger(mesh, MESHLINK_ERROR, "Could not start SPTPS session with %s: %s", from->name, strerror(errno));
239 if(!sptps_receive_data(&from->sptps, buf, len)) {
240 logger(mesh, MESHLINK_ERROR, "Could not process SPTPS data from %s: %s", from->name, strerror(errno));
248 if(!from->status.validkey) {
249 logger(mesh, MESHLINK_ERROR, "Got REQ_SPTPS from %s but we don't have a valid key yet", from->name);
253 char buf[MAX_STRING_SIZE];
256 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
257 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS", from->name, "invalid SPTPS data");
261 if(!sptps_receive_data(&from->sptps, buf, len)) {
262 logger(mesh, MESHLINK_ERROR, "Could not process SPTPS data from %s: %s", from->name, strerror(errno));
269 case REQ_CANONICAL: {
270 char host[MAX_STRING_SIZE];
271 char port[MAX_STRING_SIZE];
273 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING " " MAX_STRING, host, port) != 2) {
274 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_CANONICAL", from->name, "invalid canonical address");
278 char *canonical_address;
279 xasprintf(&canonical_address, "%s %s", host, port);
281 if(mesh->log_level <= MESHLINK_DEBUG && (!from->canonical_address || strcmp(from->canonical_address, canonical_address))) {
282 logger(mesh, MESHLINK_DEBUG, "Updating canonical address of %s to %s", from->name, canonical_address);
285 free(from->canonical_address);
286 from->canonical_address = canonical_address;
291 logger(mesh, MESHLINK_ERROR, "Unknown extended REQ_KEY request from %s: %s", from->name, request);
296 bool req_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
300 char from_name[MAX_STRING_SIZE];
301 char to_name[MAX_STRING_SIZE];
305 if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
306 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "REQ_KEY", c->name);
310 if(!check_id(from_name) || !check_id(to_name)) {
311 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_KEY", c->name, "invalid name");
315 from = lookup_node(mesh, from_name);
318 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
319 "REQ_KEY", c->name, from_name);
323 to = lookup_node(mesh, to_name);
326 logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
327 "REQ_KEY", c->name, to_name);
331 /* Check if this key request is for us */
333 if(to == mesh->self) { /* Yes */
334 /* Is this an extended REQ_KEY message? */
336 return req_key_ext_h(mesh, c, request, from, reqno);
339 /* This should never happen. Ignore it, unless it came directly from the connected peer, in which case we disconnect. */
340 return from->connection != c;
342 if(!to->status.reachable || !to->nexthop || !to->nexthop->connection) {
343 logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
344 "REQ_KEY", c->name, to_name);
348 size_t len = strlen(request);
349 from->in_forward += len + SPTPS_OVERHEAD;
350 to->out_forward += len + SPTPS_OVERHEAD;
352 send_request(mesh, to->nexthop->connection, NULL, "%s", request);
358 bool ans_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
362 char from_name[MAX_STRING_SIZE];
363 char to_name[MAX_STRING_SIZE];
364 char key[MAX_STRING_SIZE];
365 char address[MAX_STRING_SIZE] = "";
366 char port[MAX_STRING_SIZE] = "";
367 int cipher, digest, maclength, compression;
370 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
371 from_name, to_name, key, &cipher, &digest, &maclength,
372 &compression, address, port) < 7) {
373 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "ANS_KEY", c->name);
377 if(!check_id(from_name) || !check_id(to_name)) {
378 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_KEY", c->name, "invalid name");
382 from = lookup_node(mesh, from_name);
385 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
386 "ANS_KEY", c->name, from_name);
390 to = lookup_node(mesh, to_name);
393 logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
394 "ANS_KEY", c->name, to_name);
398 /* Forward it if necessary */
400 if(to != mesh->self) {
401 if(!to->status.reachable) {
402 logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
403 "ANS_KEY", c->name, to_name);
408 logger(mesh, MESHLINK_WARNING, "Got %s from %s from %s to %s",
409 "ANS_KEY", c->name, from_name, to_name);
413 if(!to->nexthop || !to->nexthop->connection) {
414 logger(mesh, MESHLINK_WARNING, "Cannot forward ANS_KEY to %s via %s", to->name, to->nexthop ? to->nexthop->name : to->name);
418 /* TODO: find a good way to avoid the use of strlen() */
419 size_t len = strlen(request);
420 from->in_forward += len + SPTPS_OVERHEAD;
421 to->out_forward += len + SPTPS_OVERHEAD;
423 /* Append the known UDP address of the from node, if we have a confirmed one */
424 if(!*address && from->status.udp_confirmed && from->address.sa.sa_family != AF_UNSPEC) {
425 char *reflexive_address, *reflexive_port;
426 logger(mesh, MESHLINK_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name);
427 sockaddr2str(&from->address, &reflexive_address, &reflexive_port);
428 send_request(mesh, to->nexthop->connection, NULL, "%s %s %s", request, reflexive_address, reflexive_port);
429 free(reflexive_address);
430 free(reflexive_port);
434 return send_request(mesh, to->nexthop->connection, NULL, "%s", request);
437 /* Is this an ANS_KEY informing us of our own reflexive UDP address? */
439 if(from == mesh->self) {
440 if(*key == '.' && *address && *port) {
441 logger(mesh, MESHLINK_DEBUG, "Learned our own reflexive UDP address from %s: %s port %s", c->name, address, port);
443 /* Inform all other nodes we want to communicate with and which are reachable via this connection */
444 for splay_each(node_t, n, mesh->nodes) {
445 if(n->nexthop != c->node) {
449 if(n->status.udp_confirmed) {
453 if(!n->status.waitingforkey && !n->status.validkey) {
457 if(!n->nexthop->connection) {
461 logger(mesh, MESHLINK_DEBUG, "Forwarding our own reflexive UDP address to %s", n->name);
462 send_request(mesh, c, NULL, "%d %s %s . -1 -1 -1 0 %s %s", ANS_KEY, mesh->self->name, n->name, address, port);
465 logger(mesh, MESHLINK_WARNING, "Got %s from %s from %s to %s",
466 "ANS_KEY", c->name, from_name, to_name);
472 /* Process SPTPS data if present */
475 /* Don't use key material until every check has passed. */
476 from->status.validkey = false;
478 /* Compression is not supported. */
479 if(compression != 0) {
480 logger(mesh, MESHLINK_ERROR, "Node %s uses bogus compression level!", from->name);
484 char buf[strlen(key)];
485 int len = b64decode(key, buf, strlen(key));
487 if(!len || !sptps_receive_data(&from->sptps, buf, len)) {
488 logger(mesh, MESHLINK_ERROR, "Error processing SPTPS data from %s", from->name);
492 if(from->status.validkey) {
493 if(*address && *port) {
494 logger(mesh, MESHLINK_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
495 sockaddr_t sa = str2sockaddr(address, port);
496 update_node_udp(mesh, from, &sa);
499 send_mtu_probe(mesh, from);