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 send_request(mesh, to->nexthop->connection, NULL, "%d %s %s %d", REQ_KEY, mesh->self->name, to->name, REQ_PUBKEY);
88 logger(mesh, MESHLINK_DEBUG, "send_req_key(%s) called while sptps->label != NULL!", to->name);
91 char label[sizeof(meshlink_udp_label) + strlen(mesh->self->name) + strlen(to->name) + 2];
92 snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, mesh->self->name, to->name);
93 sptps_stop(&to->sptps);
94 to->status.validkey = false;
95 to->status.waitingforkey = true;
96 to->last_req_key = mesh->loop.now.tv_sec;
97 return sptps_start(&to->sptps, to, true, true, mesh->private_key, to->ecdsa, label, sizeof(label) - 1, send_initial_sptps_data, receive_sptps_record);
100 /* REQ_KEY is overloaded to allow arbitrary requests to be routed between two nodes. */
102 static bool req_key_ext_h(meshlink_handle_t *mesh, connection_t *c, const char *request, node_t *from, int reqno) {
107 char *pubkey = ecdsa_get_base64_public_key(mesh->private_key);
109 if(!from->nexthop || !from->nexthop->connection) {
113 send_request(mesh, from->nexthop->connection, NULL, "%d %s %s %d %s", REQ_KEY, mesh->self->name, from->name, ANS_PUBKEY, pubkey);
119 if(node_read_public_key(mesh, from)) {
120 logger(mesh, MESHLINK_WARNING, "Got ANS_PUBKEY from %s even though we already have his pubkey", from->name);
124 char pubkey[MAX_STRING_SIZE];
126 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !(from->ecdsa = ecdsa_set_base64_public_key(pubkey))) {
127 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_PUBKEY", from->name, "invalid pubkey");
131 logger(mesh, MESHLINK_INFO, "Learned ECDSA public key from %s", from->name);
132 from->status.dirty = true;
134 /* If we are trying to form an outgoing connection to this node, retry immediately */
135 for list_each(outgoing_t, outgoing, mesh->outgoings) {
136 if(outgoing->node == from && outgoing->ev.cb) {
137 outgoing->timeout = 0;
138 timeout_set(&mesh->loop, &outgoing->ev, &(struct timespec) {
144 /* Also reset any UTCP timers */
145 utcp_reset_timers(from->utcp);
151 if(!node_read_public_key(mesh, from)) {
152 logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", from->name);
153 send_request(mesh, from->nexthop->connection, NULL, "%d %s %s %d", REQ_KEY, mesh->self->name, from->name, REQ_PUBKEY);
157 if(from->sptps.label) {
158 logger(mesh, MESHLINK_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name);
160 if(mesh->loop.now.tv_sec < from->last_req_key + req_key_timeout && strcmp(mesh->self->name, from->name) < 0) {
161 logger(mesh, MESHLINK_DEBUG, "Ignoring REQ_KEY from %s.", from->name);
166 char buf[MAX_STRING_SIZE];
169 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
170 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS_START", from->name, "invalid SPTPS data");
174 char label[sizeof(meshlink_udp_label) + strlen(from->name) + strlen(mesh->self->name) + 2];
175 snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, from->name, mesh->self->name);
176 sptps_stop(&from->sptps);
177 from->status.validkey = false;
178 from->status.waitingforkey = true;
179 from->last_req_key = mesh->loop.now.tv_sec;
181 if(!sptps_start(&from->sptps, from, false, true, mesh->private_key, from->ecdsa, label, sizeof(label) - 1, send_sptps_data, receive_sptps_record)) {
182 logger(mesh, MESHLINK_ERROR, "Could not start SPTPS session with %s: %s", from->name, strerror(errno));
186 if(!sptps_receive_data(&from->sptps, buf, len)) {
187 logger(mesh, MESHLINK_ERROR, "Could not process SPTPS data from %s: %s", from->name, strerror(errno));
195 if(!from->status.validkey) {
196 logger(mesh, MESHLINK_ERROR, "Got REQ_SPTPS from %s but we don't have a valid key yet", from->name);
200 char buf[MAX_STRING_SIZE];
203 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
204 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS", from->name, "invalid SPTPS data");
208 if(!sptps_receive_data(&from->sptps, buf, len)) {
209 logger(mesh, MESHLINK_ERROR, "Could not process SPTPS data from %s: %s", from->name, strerror(errno));
217 logger(mesh, MESHLINK_ERROR, "Unknown extended REQ_KEY request from %s: %s", from->name, request);
222 bool req_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
226 char from_name[MAX_STRING_SIZE];
227 char to_name[MAX_STRING_SIZE];
231 if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
232 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "REQ_KEY", c->name);
236 if(!check_id(from_name) || !check_id(to_name)) {
237 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_KEY", c->name, "invalid name");
241 from = lookup_node(mesh, from_name);
244 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
245 "REQ_KEY", c->name, from_name);
249 to = lookup_node(mesh, to_name);
252 logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
253 "REQ_KEY", c->name, to_name);
257 /* Check if this key request is for us */
259 if(to == mesh->self) { /* Yes */
260 /* Is this an extended REQ_KEY message? */
262 return req_key_ext_h(mesh, c, request, from, reqno);
265 /* This should never happen. Ignore it, unless it came directly from the connected peer, in which case we disconnect. */
266 return from->connection != c;
268 if(!to->status.reachable) {
269 logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
270 "REQ_KEY", c->name, to_name);
274 send_request(mesh, to->nexthop->connection, NULL, "%s", request);
280 bool ans_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
284 char from_name[MAX_STRING_SIZE];
285 char to_name[MAX_STRING_SIZE];
286 char key[MAX_STRING_SIZE];
287 char address[MAX_STRING_SIZE] = "";
288 char port[MAX_STRING_SIZE] = "";
289 int cipher, digest, maclength, compression;
292 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
293 from_name, to_name, key, &cipher, &digest, &maclength,
294 &compression, address, port) < 7) {
295 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "ANS_KEY", c->name);
299 if(!check_id(from_name) || !check_id(to_name)) {
300 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_KEY", c->name, "invalid name");
304 from = lookup_node(mesh, from_name);
307 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
308 "ANS_KEY", c->name, from_name);
312 to = lookup_node(mesh, to_name);
315 logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
316 "ANS_KEY", c->name, to_name);
320 /* Forward it if necessary */
322 if(to != mesh->self) {
323 if(!to->status.reachable) {
324 logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
325 "ANS_KEY", c->name, to_name);
330 logger(mesh, MESHLINK_WARNING, "Got %s from %s from %s to %s",
331 "ANS_KEY", c->name, from_name, to_name);
335 /* Append the known UDP address of the from node, if we have a confirmed one */
336 if(!*address && from->status.udp_confirmed && from->address.sa.sa_family != AF_UNSPEC) {
337 char *address, *port;
338 logger(mesh, MESHLINK_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name);
339 sockaddr2str(&from->address, &address, &port);
340 send_request(mesh, to->nexthop->connection, NULL, "%s %s %s", request, address, port);
346 return send_request(mesh, to->nexthop->connection, NULL, "%s", request);
349 /* Is this an ANS_KEY informing us of our own reflexive UDP address? */
351 if(from == mesh->self) {
352 if(*key == '.' && *address && *port) {
353 logger(mesh, MESHLINK_DEBUG, "Learned our own reflexive UDP address from %s: %s port %s", c->name, address, port);
355 /* Inform all other nodes we want to communicate with and which are reachable via this connection */
356 for splay_each(node_t, n, mesh->nodes) {
357 if(n->nexthop != c->node) {
361 if(n->status.udp_confirmed) {
365 if(!n->status.waitingforkey && !n->status.validkey) {
369 logger(mesh, MESHLINK_DEBUG, "Forwarding our own reflexive UDP address to %s", n->name);
370 send_request(mesh, c, NULL, "%d %s %s . -1 -1 -1 0 %s %s", ANS_KEY, mesh->self->name, n->name, address, port);
373 logger(mesh, MESHLINK_WARNING, "Got %s from %s from %s to %s",
374 "ANS_KEY", c->name, from_name, to_name);
380 /* Process SPTPS data if present */
383 /* Don't use key material until every check has passed. */
384 from->status.validkey = false;
386 /* Compression is not supported. */
387 if(compression != 0) {
388 logger(mesh, MESHLINK_ERROR, "Node %s uses bogus compression level!", from->name);
392 char buf[strlen(key)];
393 int len = b64decode(key, buf, strlen(key));
395 if(!len || !sptps_receive_data(&from->sptps, buf, len)) {
396 logger(mesh, MESHLINK_ERROR, "Error processing SPTPS data from %s", from->name);
400 if(from->status.validkey) {
401 if(*address && *port) {
402 logger(mesh, MESHLINK_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
403 sockaddr_t sa = str2sockaddr(address, port);
404 update_node_udp(mesh, from, &sa);
407 send_mtu_probe(mesh, from);