289 lines
7 KiB
C
289 lines
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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2000-2008 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
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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$Id: protocol_key.c 1595 2008-12-22 20:27:52Z guus $
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*/
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#include "system.h"
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#include <openssl/evp.h>
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#include <openssl/err.h>
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#include "avl_tree.h"
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#include "connection.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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bool mykeyused = false;
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bool send_key_changed(connection_t *c, const node_t *n)
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{
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cp();
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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(n == myself && !mykeyused)
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return true;
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return send_request(c, "%d %lx %s", KEY_CHANGED, random(), n->name);
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}
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bool key_changed_h(connection_t *c)
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{
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char name[MAX_STRING_SIZE];
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node_t *n;
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cp();
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if(sscanf(c->buffer, "%*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(c->buffer))
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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);
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return true;
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}
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bool send_req_key(connection_t *c, const node_t *from, const node_t *to)
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{
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cp();
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return send_request(c, "%d %s %s", REQ_KEY, from->name, to->name);
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}
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bool req_key_h(connection_t *c)
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{
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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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cp();
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if(sscanf(c->buffer, "%*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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mykeyused = true;
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from->received_seqno = 0;
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memset(from->late, 0, sizeof(from->late));
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send_ans_key(c, myself, 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_req_key(to->nexthop->connection, from, to);
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}
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return true;
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}
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bool send_ans_key(connection_t *c, const node_t *from, const node_t *to)
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{
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char *key;
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cp();
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key = alloca(2 * from->keylength + 1);
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bin2hex(from->key, key, from->keylength);
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key[from->keylength * 2] = '\0';
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return send_request(c, "%d %s %s %s %d %d %d %d", ANS_KEY,
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from->name, to->name, key,
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from->cipher ? from->cipher->nid : 0,
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from->digest ? from->digest->type : 0, from->maclength,
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from->compression);
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}
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bool ans_key_h(connection_t *c)
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{
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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;
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node_t *from, *to;
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cp();
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if(sscanf(c->buffer, "%*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", c->buffer);
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}
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/* Update our copy of the origin's packet key */
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if(from->key)
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free(from->key);
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from->key = xstrdup(key);
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from->keylength = strlen(key) / 2;
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hex2bin(from->key, from->key, from->keylength);
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from->key[from->keylength] = '\0';
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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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/* Check and lookup cipher and digest algorithms */
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if(cipher) {
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from->cipher = EVP_get_cipherbynid(cipher);
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if(!from->cipher) {
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logger(LOG_ERR, _("Node %s (%s) uses unknown cipher!"), from->name,
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from->hostname);
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return false;
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}
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if(from->keylength != from->cipher->key_len + from->cipher->iv_len) {
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logger(LOG_ERR, _("Node %s (%s) uses wrong keylength!"), from->name,
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from->hostname);
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return false;
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}
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} else {
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from->cipher = NULL;
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}
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from->maclength = maclength;
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if(digest) {
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from->digest = EVP_get_digestbynid(digest);
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if(!from->digest) {
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logger(LOG_ERR, _("Node %s (%s) uses unknown digest!"), from->name,
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from->hostname);
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return false;
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}
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if(from->maclength > from->digest->md_size || from->maclength < 0) {
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logger(LOG_ERR, _("Node %s (%s) uses bogus MAC length!"),
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from->name, from->hostname);
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return false;
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}
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} else {
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from->digest = NULL;
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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->compression = compression;
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if(from->cipher)
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if(!EVP_EncryptInit_ex(&from->packet_ctx, from->cipher, NULL, (unsigned char *)from->key, (unsigned char *)from->key + from->cipher->key_len)) {
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logger(LOG_ERR, _("Error during initialisation of key from %s (%s): %s"),
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from->name, from->hostname, ERR_error_string(ERR_get_error(), NULL));
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return false;
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}
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if(from->options & OPTION_PMTU_DISCOVERY && !from->mtuprobes)
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send_mtu_probe(from);
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flush_queue(from);
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return true;
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}
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