2 protocol_key.c -- handle the meta-protocol, key exchange
3 Copyright (C) 2014 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 void send_key_changed(meshlink_handle_t *mesh) {
35 send_request(mesh, mesh->everyone, "%d %x %s", KEY_CHANGED, rand(), mesh->self->name);
37 /* Force key exchange for connections using SPTPS */
39 for splay_each(node_t, n, mesh->nodes)
40 if(n->status.reachable && n->status.validkey)
41 sptps_force_kex(&n->sptps);
44 bool key_changed_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
45 char name[MAX_STRING_SIZE];
48 if(sscanf(request, "%*d %*x " MAX_STRING, name) != 1) {
49 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "KEY_CHANGED", c->name);
53 if(seen_request(mesh, request))
56 n = lookup_node(mesh, name);
59 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist", "KEY_CHANGED", c->name, name);
65 forward_request(mesh, c, request);
70 static bool send_initial_sptps_data(void *handle, uint8_t type, const void *data, size_t len) {
72 meshlink_handle_t *mesh = to->mesh;
73 to->sptps.send_data = send_sptps_data;
74 char buf[len * 4 / 3 + 5];
75 b64encode(data, buf, len);
76 return send_request(mesh, to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, mesh->self->name, to->name, REQ_KEY, buf);
79 bool send_req_key(meshlink_handle_t *mesh, node_t *to) {
80 if(!node_read_ecdsa_public_key(mesh, to)) {
81 logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", to->name);
82 send_request(mesh, to->nexthop->connection, "%d %s %s %d", REQ_KEY, mesh->self->name, to->name, REQ_PUBKEY);
87 logger(mesh, MESHLINK_DEBUG, "send_req_key(%s) called while sptps->label != NULL!", to->name);
89 char label[sizeof(meshlink_udp_label) + strlen(mesh->self->name) + strlen(to->name) + 2];
90 snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, mesh->self->name, to->name);
91 sptps_stop(&to->sptps);
92 to->status.validkey = false;
93 to->status.waitingforkey = true;
94 to->last_req_key = mesh->loop.now.tv_sec;
95 to->incompression = mesh->self->incompression;
96 return sptps_start(&to->sptps, to, true, true, mesh->self->connection->ecdsa, to->ecdsa, label, sizeof(label) - 1, send_initial_sptps_data, receive_sptps_record);
99 /* REQ_KEY is overloaded to allow arbitrary requests to be routed between two nodes. */
101 static bool req_key_ext_h(meshlink_handle_t *mesh, connection_t *c, const char *request, node_t *from, int reqno) {
104 char *pubkey = ecdsa_get_base64_public_key(mesh->self->connection->ecdsa);
105 send_request(mesh, from->nexthop->connection, "%d %s %s %d %s", REQ_KEY, mesh->self->name, from->name, ANS_PUBKEY, pubkey);
111 if(node_read_ecdsa_public_key(mesh, from)) {
112 logger(mesh, MESHLINK_WARNING, "Got ANS_PUBKEY from %s even though we already have his pubkey", from->name);
116 char pubkey[MAX_STRING_SIZE];
117 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !(from->ecdsa = ecdsa_set_base64_public_key(pubkey))) {
118 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_PUBKEY", from->name, "invalid pubkey");
122 logger(mesh, MESHLINK_INFO, "Learned ECDSA public key from %s", from->name);
123 append_config_file(mesh, from->name, "ECDSAPublicKey", pubkey);
128 if(!node_read_ecdsa_public_key(mesh, from)) {
129 logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", from->name);
130 send_request(mesh, from->nexthop->connection, "%d %s %s %d", REQ_KEY, mesh->self->name, from->name, REQ_PUBKEY);
134 if(from->sptps.label) {
135 logger(mesh, MESHLINK_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name);
136 if(strcmp(mesh->self->name, from->name) < 0) {
137 logger(mesh, MESHLINK_DEBUG, "Ignoring REQ_KEY from %s.", from->name);
142 char buf[MAX_STRING_SIZE];
145 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
146 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS_START", from->name, "invalid SPTPS data");
150 char label[sizeof(meshlink_udp_label) + strlen(from->name) + strlen(mesh->self->name) + 2];
151 snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, from->name, mesh->self->name);
152 sptps_stop(&from->sptps);
153 from->status.validkey = false;
154 from->status.waitingforkey = true;
155 from->last_req_key = mesh->loop.now.tv_sec;
156 sptps_start(&from->sptps, from, false, true, mesh->self->connection->ecdsa, from->ecdsa, label, sizeof(label) - 1, send_sptps_data, receive_sptps_record);
157 sptps_receive_data(&from->sptps, buf, len);
162 if(!from->status.validkey) {
163 logger(mesh, MESHLINK_ERROR, "Got REQ_SPTPS from %s but we don't have a valid key yet", from->name);
167 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", from->name, "invalid SPTPS data");
173 sptps_receive_data(&from->sptps, buf, len);
178 logger(mesh, MESHLINK_ERROR, "Unknown extended REQ_KEY request from %s: %s", from->name, request);
183 bool req_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
184 char from_name[MAX_STRING_SIZE];
185 char to_name[MAX_STRING_SIZE];
189 if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
190 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "REQ_KEY", c->name);
194 if(!check_id(from_name) || !check_id(to_name)) {
195 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_KEY", c->name, "invalid name");
199 from = lookup_node(mesh, from_name);
202 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
203 "REQ_KEY", c->name, from_name);
207 to = lookup_node(mesh, to_name);
210 logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
211 "REQ_KEY", c->name, to_name);
215 /* Check if this key request is for us */
217 if(to == mesh->self) { /* Yes */
218 /* Is this an extended REQ_KEY message? */
220 return req_key_ext_h(mesh, c, request, from, reqno);
222 /* No, just send our key back */
223 send_ans_key(mesh, from);
225 if(!to->status.reachable) {
226 logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
227 "REQ_KEY", c->name, to_name);
231 send_request(mesh, to->nexthop->connection, "%s", request);
237 bool send_ans_key(meshlink_handle_t *mesh, node_t *to) {
241 bool ans_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
242 char from_name[MAX_STRING_SIZE];
243 char to_name[MAX_STRING_SIZE];
244 char key[MAX_STRING_SIZE];
245 char address[MAX_STRING_SIZE] = "";
246 char port[MAX_STRING_SIZE] = "";
247 int cipher, digest, maclength, compression;
250 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
251 from_name, to_name, key, &cipher, &digest, &maclength,
252 &compression, address, port) < 7) {
253 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "ANS_KEY", c->name);
257 if(!check_id(from_name) || !check_id(to_name)) {
258 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_KEY", c->name, "invalid name");
262 from = lookup_node(mesh, from_name);
265 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
266 "ANS_KEY", c->name, from_name);
270 to = lookup_node(mesh, to_name);
273 logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
274 "ANS_KEY", c->name, to_name);
278 /* Forward it if necessary */
280 if(to != mesh->self) {
281 if(!to->status.reachable) {
282 logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
283 "ANS_KEY", c->name, to_name);
287 if(!*address && from->address.sa.sa_family != AF_UNSPEC) {
288 char *address, *port;
289 logger(mesh, MESHLINK_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name);
290 sockaddr2str(&from->address, &address, &port);
291 send_request(mesh, to->nexthop->connection, "%s %s %s", request, address, port);
297 return send_request(mesh, to->nexthop->connection, "%s", request);
300 /* Don't use key material until every check has passed. */
301 from->status.validkey = false;
303 /* Compression is not supported. */
304 if(compression != 0) {
305 logger(mesh, MESHLINK_ERROR, "Node %s uses bogus compression level!", from->name);
309 from->outcompression = compression;
311 /* SPTPS or old-style key exchange? */
313 char buf[strlen(key)];
314 int len = b64decode(key, buf, strlen(key));
316 if(!len || !sptps_receive_data(&from->sptps, buf, len))
317 logger(mesh, MESHLINK_ERROR, "Error processing SPTPS data from %s", from->name);
319 if(from->status.validkey) {
320 if(*address && *port) {
321 logger(mesh, MESHLINK_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
322 sockaddr_t sa = str2sockaddr(address, port);
323 update_node_udp(mesh, from, &sa);
326 if(from->options & OPTION_PMTU_DISCOVERY && !(from->options & OPTION_TCPONLY))
327 send_mtu_probe(mesh, from);