c845bc109c
This wasn't working at all, since we didn't do HMAC but just a plain hash. Also, verification of packets failed because it was checking the whole packet, not the packet minus the HMAC.
251 lines
6.7 KiB
C
251 lines
6.7 KiB
C
/*
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protocol_key.c -- handle the meta-protocol, key exchange
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Copyright (C) 1999-2005 Ivo Timmermans,
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2000-2009 Guus Sliepen <guus@tinc-vpn.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "system.h"
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#include "splay_tree.h"
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#include "cipher.h"
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#include "connection.h"
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#include "crypto.h"
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#include "logger.h"
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#include "net.h"
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#include "netutl.h"
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#include "node.h"
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#include "protocol.h"
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#include "utils.h"
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#include "xalloc.h"
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static bool mykeyused = false;
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bool send_key_changed() {
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/* Only send this message if some other daemon requested our key previously.
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This reduces unnecessary key_changed broadcasts.
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*/
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if(!mykeyused)
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return true;
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return send_request(broadcast, "%d %x %s", KEY_CHANGED, rand(), myself->name);
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}
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bool key_changed_h(connection_t *c, char *request) {
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char name[MAX_STRING_SIZE];
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node_t *n;
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if(sscanf(request, "%*d %*x " MAX_STRING, name) != 1) {
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logger(LOG_ERR, "Got bad %s from %s (%s)", "KEY_CHANGED",
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c->name, c->hostname);
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return false;
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}
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if(seen_request(request))
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return true;
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n = lookup_node(name);
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if(!n) {
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logger(LOG_ERR, "Got %s from %s (%s) origin %s which does not exist",
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"KEY_CHANGED", c->name, c->hostname, name);
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return false;
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}
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n->status.validkey = false;
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n->status.waitingforkey = false;
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/* Tell the others */
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if(!tunnelserver)
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forward_request(c, request);
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return true;
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}
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bool send_req_key(node_t *to) {
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return send_request(to->nexthop->connection, "%d %s %s", REQ_KEY, myself->name, to->name);
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}
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bool req_key_h(connection_t *c, char *request) {
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char from_name[MAX_STRING_SIZE];
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char to_name[MAX_STRING_SIZE];
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node_t *from, *to;
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if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING, from_name, to_name) != 2) {
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logger(LOG_ERR, "Got bad %s from %s (%s)", "REQ_KEY", c->name,
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c->hostname);
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return false;
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}
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from = lookup_node(from_name);
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if(!from) {
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logger(LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
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"REQ_KEY", c->name, c->hostname, from_name);
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return false;
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}
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to = lookup_node(to_name);
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if(!to) {
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logger(LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
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"REQ_KEY", c->name, c->hostname, to_name);
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return false;
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}
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/* Check if this key request is for us */
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if(to == myself) { /* Yes, send our own key back */
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send_ans_key(from);
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} else {
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if(tunnelserver)
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return false;
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if(!to->status.reachable) {
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logger(LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
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"REQ_KEY", c->name, c->hostname, to_name);
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return true;
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}
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send_request(to->nexthop->connection, "%s", request);
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}
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return true;
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}
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bool send_ans_key(node_t *to) {
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size_t keylen = cipher_keylength(&myself->incipher);
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char key[keylen * 2 + 1];
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cipher_open_by_nid(&to->incipher, cipher_get_nid(&myself->incipher));
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digest_open_by_nid(&to->indigest, digest_get_nid(&myself->indigest), digest_length(&myself->indigest));
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to->incompression = myself->incompression;
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randomize(key, keylen);
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cipher_set_key(&to->incipher, key, true);
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digest_set_key(&to->indigest, key, keylen);
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bin2hex(key, key, keylen);
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key[keylen * 2] = '\0';
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// Reset sequence number and late packet window
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mykeyused = true;
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to->received_seqno = 0;
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memset(to->late, 0, sizeof(to->late));
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return send_request(to->nexthop->connection, "%d %s %s %s %d %d %zu %d", ANS_KEY,
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myself->name, to->name, key,
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cipher_get_nid(&to->incipher),
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digest_get_nid(&to->indigest),
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digest_length(&to->indigest),
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to->incompression);
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}
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bool ans_key_h(connection_t *c, char *request) {
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char from_name[MAX_STRING_SIZE];
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char to_name[MAX_STRING_SIZE];
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char key[MAX_STRING_SIZE];
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int cipher, digest, maclength, compression, keylen;
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node_t *from, *to;
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if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d",
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from_name, to_name, key, &cipher, &digest, &maclength,
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&compression) != 7) {
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logger(LOG_ERR, "Got bad %s from %s (%s)", "ANS_KEY", c->name,
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c->hostname);
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return false;
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}
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from = lookup_node(from_name);
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if(!from) {
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logger(LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
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"ANS_KEY", c->name, c->hostname, from_name);
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return false;
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}
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to = lookup_node(to_name);
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if(!to) {
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logger(LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
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"ANS_KEY", c->name, c->hostname, to_name);
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return false;
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}
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/* Forward it if necessary */
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if(to != myself) {
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if(tunnelserver)
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return false;
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if(!to->status.reachable) {
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logger(LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
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"ANS_KEY", c->name, c->hostname, to_name);
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return true;
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}
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return send_request(to->nexthop->connection, "%s", request);
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}
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/* Check and lookup cipher and digest algorithms */
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if(!cipher_open_by_nid(&from->outcipher, cipher)) {
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logger(LOG_ERR, "Node %s (%s) uses unknown cipher!", from->name, from->hostname);
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return false;
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}
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keylen = strlen(key) / 2;
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if(keylen != cipher_keylength(&from->outcipher)) {
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logger(LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name, from->hostname);
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return false;
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}
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if(!digest_open_by_nid(&from->outdigest, digest, maclength)) {
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logger(LOG_ERR, "Node %s (%s) uses unknown digest!", from->name, from->hostname);
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return false;
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}
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if(maclength != digest_length(&from->outdigest)) {
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logger(LOG_ERR, "Node %s (%s) uses bogus MAC length!", from->name, from->hostname);
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return false;
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}
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if(compression < 0 || compression > 11) {
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logger(LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname);
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return false;
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}
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from->outcompression = compression;
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/* Update our copy of the origin's packet key */
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hex2bin(key, key, keylen);
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cipher_set_key(&from->outcipher, key, false);
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digest_set_key(&from->outdigest, key, keylen);
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from->status.validkey = true;
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from->status.waitingforkey = false;
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from->sent_seqno = 0;
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if(from->options & OPTION_PMTU_DISCOVERY && !from->mtuprobes)
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send_mtu_probe(from);
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return true;
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}
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