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/*
* Copyright (c) 1997-2002 Motonori Nakamura <motonori@media.kyoto-u.ac.jp>
* Copyright (c) 1997-2002 WIDE Project
* Copyright (c) 1997-2002 Kyoto University
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by WIDE Project and
* its contributors.
* 4. Neither the name of the Project, the University nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Copyright (c) 1986, 1995-1997 Eric P. Allman
* Copyright (c) 1988, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
static char *_id_ = "$Id: mxrand.c,v 1.7 2002/01/20 14:19:39 motonori Exp $";
static char sccsid[] = "@(#)domain.c 8.68 (Berkeley) 8/2/97 (with name server)";
#endif /* not lint */
# include "common.h"
/*
** CURTIME -- return current time.
**
** Parameters:
** none.
**
** Returns:
** the current time.
**
** Side Effects:
** none.
*/
time_t
curtime()
{
auto time_t t;
(void) time(&t);
return (t);
}
/*
** MXRAND -- create a randomizer for equal MX preferences
**
** If two MX hosts have equal preferences we want to randomize
** the selection. But in order for signatures to be the same,
** we need to randomize the same way each time. This function
** computes a pseudo-random hash function from the host name.
**
** Parameters:
** host -- the name of the host.
**
** Returns:
** A random but repeatable value based on the host name.
**
** Side Effects:
** none.
*/
int
mxrand(host1, host2)
register char *host1, *host2;
{
int hfunc;
static unsigned int seed;
if (seed == 0)
{
seed = (int) curtime() & 0xffff;
if (seed == 0)
seed++;
}
#if 0
if (tTd(17, 9))
printf("mxrand(%s)", host);
#endif
hfunc = seed;
while (*host1 != '\0')
{
int c = *host1++;
if (isascii(c) && isupper(c))
c = tolower(c);
hfunc = ((hfunc << 1) ^ c) % 2003;
}
while (*host2 != '\0')
{
int c = *host2++;
if (isascii(c) && isupper(c))
c = tolower(c);
hfunc = ((hfunc << 1) ^ c) % 2003;
}
hfunc &= 0xff;
hfunc++;
#if 0
if (tTd(17, 9))
printf(" = %d\n", hfunc);
#endif
return hfunc;
}
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