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;
74 to->sptps.send_data = send_sptps_data;
75 char buf[len * 4 / 3 + 5];
76 b64encode(data, buf, len);
77 return send_request(mesh, to->nexthop->connection, NULL, "%d %s %s %d %s", REQ_KEY, mesh->self->name, to->name, REQ_KEY, buf);
80 bool send_req_key(meshlink_handle_t *mesh, node_t *to) {
81 if(!node_read_public_key(mesh, to)) {
82 logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", to->name);
83 char *pubkey = ecdsa_get_base64_public_key(mesh->private_key);
84 send_request(mesh, to->nexthop->connection, NULL, "%d %s %s %d %s", REQ_KEY, mesh->self->name, to->name, REQ_PUBKEY, pubkey);
90 logger(mesh, MESHLINK_DEBUG, "send_req_key(%s) called while sptps->label != NULL!", to->name);
93 char label[sizeof(meshlink_udp_label) + strlen(mesh->self->name) + strlen(to->name) + 2];
94 snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, mesh->self->name, to->name);
95 sptps_stop(&to->sptps);
96 to->status.validkey = false;
97 to->status.waitingforkey = true;
98 to->last_req_key = mesh->loop.now.tv_sec;
99 return sptps_start(&to->sptps, to, true, true, mesh->private_key, to->ecdsa, label, sizeof(label) - 1, send_initial_sptps_data, receive_sptps_record);
102 /* REQ_KEY is overloaded to allow arbitrary requests to be routed between two nodes. */
104 static bool req_key_ext_h(meshlink_handle_t *mesh, connection_t *c, const char *request, node_t *from, int reqno) {
109 char *pubkey = ecdsa_get_base64_public_key(mesh->private_key);
111 if(!from->nexthop || !from->nexthop->connection) {
115 if(!node_read_public_key(mesh, from)) {
116 char hiskey[MAX_STRING_SIZE];
118 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, hiskey) == 1) {
119 from->ecdsa = ecdsa_set_base64_public_key(hiskey);
122 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_PUBKEY", from->name, "invalid pubkey");
128 send_request(mesh, from->nexthop->connection, NULL, "%d %s %s %d %s", REQ_KEY, mesh->self->name, from->name, ANS_PUBKEY, pubkey);
134 if(node_read_public_key(mesh, from)) {
135 logger(mesh, MESHLINK_WARNING, "Got ANS_PUBKEY from %s even though we already have his pubkey", from->name);
139 char pubkey[MAX_STRING_SIZE];
141 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !(from->ecdsa = ecdsa_set_base64_public_key(pubkey))) {
142 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_PUBKEY", from->name, "invalid pubkey");
146 logger(mesh, MESHLINK_INFO, "Learned ECDSA public key from %s", from->name);
147 from->status.dirty = true;
149 /* If we are trying to form an outgoing connection to this node, retry immediately */
150 for list_each(outgoing_t, outgoing, mesh->outgoings) {
151 if(outgoing->node == from && outgoing->ev.cb) {
152 outgoing->timeout = 0;
153 timeout_set(&mesh->loop, &outgoing->ev, &(struct timespec) {
159 /* Also reset any UTCP timers */
160 utcp_reset_timers(from->utcp);
166 if(!node_read_public_key(mesh, from)) {
167 logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", from->name);
168 send_request(mesh, from->nexthop->connection, NULL, "%d %s %s %d", REQ_KEY, mesh->self->name, from->name, REQ_PUBKEY);
172 if(from->sptps.label) {
173 logger(mesh, MESHLINK_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name);
175 if(mesh->loop.now.tv_sec < from->last_req_key + req_key_timeout && strcmp(mesh->self->name, from->name) < 0) {
176 logger(mesh, MESHLINK_DEBUG, "Ignoring REQ_KEY from %s.", from->name);
181 char buf[MAX_STRING_SIZE];
184 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
185 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS_START", from->name, "invalid SPTPS data");
189 char label[sizeof(meshlink_udp_label) + strlen(from->name) + strlen(mesh->self->name) + 2];
190 snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, from->name, mesh->self->name);
191 sptps_stop(&from->sptps);
192 from->status.validkey = false;
193 from->status.waitingforkey = true;
194 from->last_req_key = mesh->loop.now.tv_sec;
196 if(!sptps_start(&from->sptps, from, false, true, mesh->private_key, from->ecdsa, label, sizeof(label) - 1, send_sptps_data, receive_sptps_record)) {
197 logger(mesh, MESHLINK_ERROR, "Could not start SPTPS session with %s: %s", from->name, strerror(errno));
201 if(!sptps_receive_data(&from->sptps, buf, len)) {
202 logger(mesh, MESHLINK_ERROR, "Could not process SPTPS data from %s: %s", from->name, strerror(errno));
210 if(!from->status.validkey) {
211 logger(mesh, MESHLINK_ERROR, "Got REQ_SPTPS from %s but we don't have a valid key yet", from->name);
215 char buf[MAX_STRING_SIZE];
218 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
219 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS", from->name, "invalid SPTPS data");
223 if(!sptps_receive_data(&from->sptps, buf, len)) {
224 logger(mesh, MESHLINK_ERROR, "Could not process SPTPS data from %s: %s", from->name, strerror(errno));
232 logger(mesh, MESHLINK_ERROR, "Unknown extended REQ_KEY request from %s: %s", from->name, request);
237 bool req_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
241 char from_name[MAX_STRING_SIZE];
242 char to_name[MAX_STRING_SIZE];
246 if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
247 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "REQ_KEY", c->name);
251 if(!check_id(from_name) || !check_id(to_name)) {
252 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_KEY", c->name, "invalid name");
256 from = lookup_node(mesh, from_name);
259 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
260 "REQ_KEY", c->name, from_name);
264 to = lookup_node(mesh, to_name);
267 logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
268 "REQ_KEY", c->name, to_name);
272 /* Check if this key request is for us */
274 if(to == mesh->self) { /* Yes */
275 /* Is this an extended REQ_KEY message? */
277 return req_key_ext_h(mesh, c, request, from, reqno);
280 /* This should never happen. Ignore it, unless it came directly from the connected peer, in which case we disconnect. */
281 return from->connection != c;
283 if(!to->status.reachable) {
284 logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
285 "REQ_KEY", c->name, to_name);
289 send_request(mesh, to->nexthop->connection, NULL, "%s", request);
295 bool ans_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
299 char from_name[MAX_STRING_SIZE];
300 char to_name[MAX_STRING_SIZE];
301 char key[MAX_STRING_SIZE];
302 char address[MAX_STRING_SIZE] = "";
303 char port[MAX_STRING_SIZE] = "";
304 int cipher, digest, maclength, compression;
307 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
308 from_name, to_name, key, &cipher, &digest, &maclength,
309 &compression, address, port) < 7) {
310 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "ANS_KEY", c->name);
314 if(!check_id(from_name) || !check_id(to_name)) {
315 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_KEY", c->name, "invalid name");
319 from = lookup_node(mesh, from_name);
322 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
323 "ANS_KEY", c->name, from_name);
327 to = lookup_node(mesh, to_name);
330 logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
331 "ANS_KEY", c->name, to_name);
335 /* Forward it if necessary */
337 if(to != mesh->self) {
338 if(!to->status.reachable) {
339 logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
340 "ANS_KEY", c->name, to_name);
345 logger(mesh, MESHLINK_WARNING, "Got %s from %s from %s to %s",
346 "ANS_KEY", c->name, from_name, to_name);
350 /* Append the known UDP address of the from node, if we have a confirmed one */
351 if(!*address && from->status.udp_confirmed && from->address.sa.sa_family != AF_UNSPEC) {
352 char *reflexive_address, *reflexive_port;
353 logger(mesh, MESHLINK_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name);
354 sockaddr2str(&from->address, &reflexive_address, &reflexive_port);
355 send_request(mesh, to->nexthop->connection, NULL, "%s %s %s", request, reflexive_address, reflexive_port);
356 free(reflexive_address);
357 free(reflexive_port);
361 return send_request(mesh, to->nexthop->connection, NULL, "%s", request);
364 /* Is this an ANS_KEY informing us of our own reflexive UDP address? */
366 if(from == mesh->self) {
367 if(*key == '.' && *address && *port) {
368 logger(mesh, MESHLINK_DEBUG, "Learned our own reflexive UDP address from %s: %s port %s", c->name, address, port);
370 /* Inform all other nodes we want to communicate with and which are reachable via this connection */
371 for splay_each(node_t, n, mesh->nodes) {
372 if(n->nexthop != c->node) {
376 if(n->status.udp_confirmed) {
380 if(!n->status.waitingforkey && !n->status.validkey) {
384 logger(mesh, MESHLINK_DEBUG, "Forwarding our own reflexive UDP address to %s", n->name);
385 send_request(mesh, c, NULL, "%d %s %s . -1 -1 -1 0 %s %s", ANS_KEY, mesh->self->name, n->name, address, port);
388 logger(mesh, MESHLINK_WARNING, "Got %s from %s from %s to %s",
389 "ANS_KEY", c->name, from_name, to_name);
395 /* Process SPTPS data if present */
398 /* Don't use key material until every check has passed. */
399 from->status.validkey = false;
401 /* Compression is not supported. */
402 if(compression != 0) {
403 logger(mesh, MESHLINK_ERROR, "Node %s uses bogus compression level!", from->name);
407 char buf[strlen(key)];
408 int len = b64decode(key, buf, strlen(key));
410 if(!len || !sptps_receive_data(&from->sptps, buf, len)) {
411 logger(mesh, MESHLINK_ERROR, "Error processing SPTPS data from %s", from->name);
415 if(from->status.validkey) {
416 if(*address && *port) {
417 logger(mesh, MESHLINK_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
418 sockaddr_t sa = str2sockaddr(address, port);
419 update_node_udp(mesh, from, &sa);
422 send_mtu_probe(mesh, from);