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/* routines for state objects
* Copyright (C) 1997 Angelos D. Keromytis.
* Copyright (C) 1998-2001, 2013 D. Hugh Redelmeier <hugh@mimosa.com>
* Copyright (C) 2003-2008 Michael C Richardson <mcr@xelerance.com>
* Copyright (C) 2003-2010 Paul Wouters <paul@xelerance.com>
* Copyright (C) 2008-2009 David McCullough <david_mccullough@securecomputing.com>
* Copyright (C) 2009,2012 Avesh Agarwal <avagarwa@redhat.com>
* Copyright (C) 2012-2013 Paul Wouters <pwouters@redhat.com>
* Copyright (C) 2012 Wes Hardaker <opensource@hardakers.net>
* Copyright (C) 2012 Bram <bram-bcrafjna-erqzvar@spam.wizbit.be>
* Copyright (C) 2012-2013 Paul Wouters <paul@libreswan.org>
* Copyright (C) 2013 Tuomo Soini <tis@foobar.fi>
* Copyright (C) 2013 Matt Rogers <mrogers@redhat.com>
* Copyright (C) 2013 Florian Weimer <fweimer@redhat.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <https://www.gnu.org/licenses/gpl2.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include "rnd.h"
#include "defs.h"
#include "state.h"
#include "ikev1_msgid.h"
#include "log.h"
/* IKEv1 Message-IDs
*
* A Message ID is contained in each IKE message header.
* For Phase 1 exchanges (Main and Aggressive), it will be zero.
* For other exchanges, which must be under the protection of an
* ISAKMP SA, the Message ID must be unique within that ISAKMP SA.
* Effectively, this labels the message as belonging to a particular
* exchange.
* BTW, we feel this uniqueness allows rekeying to be somewhat simpler
* than specified by draft-jenkins-ipsec-rekeying-06.txt.
*
* A MessageID is a 32 bit unsigned number. We represent the value
* internally in network order -- they are just blobs to us.
* They are unsigned numbers to make hashing and comparing easy.
*
* The following mechanism is used to allocate message IDs. This
* requires that we keep track of which numbers have already been used
* so that we don't allocate one in use.
*
* Note that IKEv2 message IDs are 0 for the initial exchanges, and
* incremented by 1 for subsequent exchanges, so the below functions
* are only required for IKEv1.
*/
struct msgid_list {
msgid_t msgid; /* network order */
struct msgid_list *next;
};
bool unique_msgid(const struct state *st, msgid_t msgid)
{
struct msgid_list *p;
passert(msgid != v1_MAINMODE_MSGID);
passert(IS_V1_ISAKMP_ENCRYPTED(st->st_state->kind));
for (p = st->st_used_msgids; p != NULL; p = p->next)
if (p->msgid == msgid)
return false;
return true;
}
void reserve_msgid(struct state *st, msgid_t msgid)
{
struct msgid_list *p;
passert(IS_V1_PHASE1(st->st_state->kind) || IS_V1_PHASE15(st->st_state->kind));
p = alloc_thing(struct msgid_list, "msgid");
p->msgid = msgid;
p->next = st->st_used_msgids;
st->st_used_msgids = p;
}
msgid_t generate_msgid(const struct state *st)
{
int timeout = 100; /* only try so hard for unique msgid */
msgid_t msgid;
passert(IS_V1_ISAKMP_ENCRYPTED(st->st_state->kind));
for (;; ) {
get_rnd_bytes((void *) &msgid, sizeof(msgid));
if (msgid != v1_MAINMODE_MSGID && unique_msgid(st, msgid))
break;
if (--timeout == 0) {
log_state(RC_LOG, st,
"gave up looking for unique msgid; using %08" PRIx32,
msgid);
break;
}
}
return msgid;
}
void ikev1_clear_msgid_list(const struct state *st)
{
struct msgid_list *p = st->st_used_msgids;
passert(st->st_state->kind == STATE_UNDEFINED);
while (p != NULL) {
struct msgid_list *q = p;
p = p->next;
pfree(q);
}
}
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