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 void send_key_changed(meshlink_handle_t *mesh) {
37 send_request(mesh, mesh->everyone, NULL, "%d %x %s", KEY_CHANGED, rand(), mesh->self->name);
39 /* Force key exchange for connections using SPTPS */
41 for splay_each(node_t, n, mesh->nodes)
42 if(n->status.reachable && n->status.validkey) {
43 sptps_force_kex(&n->sptps);
47 bool key_changed_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
48 char name[MAX_STRING_SIZE];
51 if(sscanf(request, "%*d %*x " MAX_STRING, name) != 1) {
52 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "KEY_CHANGED", c->name);
56 if(seen_request(mesh, request)) {
60 n = lookup_node(mesh, name);
63 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist", "KEY_CHANGED", c->name, name);
69 forward_request(mesh, c, NULL, request);
74 static bool send_initial_sptps_data(void *handle, uint8_t type, const void *data, size_t len) {
77 meshlink_handle_t *mesh = to->mesh;
78 to->sptps.send_data = send_sptps_data;
79 char buf[len * 4 / 3 + 5];
80 b64encode(data, buf, len);
81 return send_request(mesh, to->nexthop->connection, NULL, "%d %s %s %d %s", REQ_KEY, mesh->self->name, to->name, REQ_KEY, buf);
84 bool send_req_key(meshlink_handle_t *mesh, node_t *to) {
85 if(!node_read_public_key(mesh, to)) {
86 logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", to->name);
87 send_request(mesh, to->nexthop->connection, NULL, "%d %s %s %d", REQ_KEY, mesh->self->name, to->name, REQ_PUBKEY);
92 logger(mesh, MESHLINK_DEBUG, "send_req_key(%s) called while sptps->label != NULL!", to->name);
95 char label[sizeof(meshlink_udp_label) + strlen(mesh->self->name) + strlen(to->name) + 2];
96 snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, mesh->self->name, to->name);
97 sptps_stop(&to->sptps);
98 to->status.validkey = false;
99 to->status.waitingforkey = true;
100 to->last_req_key = mesh->loop.now.tv_sec;
101 return sptps_start(&to->sptps, to, true, true, mesh->private_key, to->ecdsa, label, sizeof(label) - 1, send_initial_sptps_data, receive_sptps_record);
104 /* REQ_KEY is overloaded to allow arbitrary requests to be routed between two nodes. */
106 static bool req_key_ext_h(meshlink_handle_t *mesh, connection_t *c, const char *request, node_t *from, int reqno) {
111 char *pubkey = ecdsa_get_base64_public_key(mesh->private_key);
113 if(!from->nexthop || !from->nexthop->connection) {
117 send_request(mesh, from->nexthop->connection, NULL, "%d %s %s %d %s", REQ_KEY, mesh->self->name, from->name, ANS_PUBKEY, pubkey);
123 if(node_read_public_key(mesh, from)) {
124 logger(mesh, MESHLINK_WARNING, "Got ANS_PUBKEY from %s even though we already have his pubkey", from->name);
128 char pubkey[MAX_STRING_SIZE];
130 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !(from->ecdsa = ecdsa_set_base64_public_key(pubkey))) {
131 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_PUBKEY", from->name, "invalid pubkey");
135 logger(mesh, MESHLINK_INFO, "Learned ECDSA public key from %s", from->name);
136 from->status.dirty = true;
138 /* If we are trying to form an outgoing connection to this node, retry immediately */
139 for list_each(outgoing_t, outgoing, mesh->outgoings) {
140 if(outgoing->node == from && outgoing->ev.cb) {
141 outgoing->timeout = 0;
142 timeout_set(&mesh->loop, &outgoing->ev, &(struct timeval) {
152 if(!node_read_public_key(mesh, from)) {
153 logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", from->name);
154 send_request(mesh, from->nexthop->connection, NULL, "%d %s %s %d", REQ_KEY, mesh->self->name, from->name, REQ_PUBKEY);
158 if(from->sptps.label) {
159 logger(mesh, MESHLINK_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name);
161 if(mesh->loop.now.tv_sec < from->last_req_key + req_key_timeout && strcmp(mesh->self->name, from->name) < 0) {
162 logger(mesh, MESHLINK_DEBUG, "Ignoring REQ_KEY from %s.", from->name);
167 char buf[MAX_STRING_SIZE];
170 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
171 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS_START", from->name, "invalid SPTPS data");
175 char label[sizeof(meshlink_udp_label) + strlen(from->name) + strlen(mesh->self->name) + 2];
176 snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, from->name, mesh->self->name);
177 sptps_stop(&from->sptps);
178 from->status.validkey = false;
179 from->status.waitingforkey = true;
180 from->last_req_key = mesh->loop.now.tv_sec;
181 sptps_start(&from->sptps, from, false, true, mesh->private_key, from->ecdsa, label, sizeof(label) - 1, send_sptps_data, receive_sptps_record);
182 sptps_receive_data(&from->sptps, buf, len);
187 if(!from->status.validkey) {
188 logger(mesh, MESHLINK_ERROR, "Got REQ_SPTPS from %s but we don't have a valid key yet", from->name);
192 char buf[MAX_STRING_SIZE];
195 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
196 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS", from->name, "invalid SPTPS data");
200 sptps_receive_data(&from->sptps, buf, len);
205 logger(mesh, MESHLINK_ERROR, "Unknown extended REQ_KEY request from %s: %s", from->name, request);
210 bool req_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
211 char from_name[MAX_STRING_SIZE];
212 char to_name[MAX_STRING_SIZE];
216 if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
217 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "REQ_KEY", c->name);
221 if(!check_id(from_name) || !check_id(to_name)) {
222 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_KEY", c->name, "invalid name");
226 from = lookup_node(mesh, from_name);
229 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
230 "REQ_KEY", c->name, from_name);
234 to = lookup_node(mesh, to_name);
237 logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
238 "REQ_KEY", c->name, to_name);
242 /* Check if this key request is for us */
244 if(to == mesh->self) { /* Yes */
245 /* Is this an extended REQ_KEY message? */
247 return req_key_ext_h(mesh, c, request, from, reqno);
250 /* This should never happen. Ignore it, unless it came directly from the connected peer, in which case we disconnect. */
251 return from->connection != c;
253 if(!to->status.reachable) {
254 logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
255 "REQ_KEY", c->name, to_name);
259 send_request(mesh, to->nexthop->connection, NULL, "%s", request);
265 bool send_ans_key(meshlink_handle_t *mesh, node_t *to) {
271 bool ans_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
272 char from_name[MAX_STRING_SIZE];
273 char to_name[MAX_STRING_SIZE];
274 char key[MAX_STRING_SIZE];
275 char address[MAX_STRING_SIZE] = "";
276 char port[MAX_STRING_SIZE] = "";
277 int cipher, digest, maclength, compression;
280 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
281 from_name, to_name, key, &cipher, &digest, &maclength,
282 &compression, address, port) < 7) {
283 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "ANS_KEY", c->name);
287 if(!check_id(from_name) || !check_id(to_name)) {
288 logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_KEY", c->name, "invalid name");
292 from = lookup_node(mesh, from_name);
295 logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
296 "ANS_KEY", c->name, from_name);
300 to = lookup_node(mesh, to_name);
303 logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
304 "ANS_KEY", c->name, to_name);
308 /* Forward it if necessary */
310 if(to != mesh->self) {
311 if(!to->status.reachable) {
312 logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
313 "ANS_KEY", c->name, to_name);
317 if(!*address && from->address.sa.sa_family != AF_UNSPEC) {
318 char *address, *port;
319 logger(mesh, MESHLINK_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name);
320 sockaddr2str(&from->address, &address, &port);
321 send_request(mesh, to->nexthop->connection, NULL, "%s %s %s", request, address, port);
327 return send_request(mesh, to->nexthop->connection, NULL, "%s", request);
330 /* Don't use key material until every check has passed. */
331 from->status.validkey = false;
333 /* Compression is not supported. */
334 if(compression != 0) {
335 logger(mesh, MESHLINK_ERROR, "Node %s uses bogus compression level!", from->name);
339 /* SPTPS or old-style key exchange? */
341 char buf[strlen(key)];
342 int len = b64decode(key, buf, strlen(key));
344 if(!len || !sptps_receive_data(&from->sptps, buf, len)) {
345 logger(mesh, MESHLINK_ERROR, "Error processing SPTPS data from %s", from->name);
348 if(from->status.validkey) {
349 if(*address && *port) {
350 logger(mesh, MESHLINK_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
351 sockaddr_t sa = str2sockaddr(address, port);
352 update_node_udp(mesh, from, &sa);
355 send_mtu_probe(mesh, from);