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/*-
* Copyright (c) 2010 David Malone <dwmalone@FreeBSD.org>
* 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.
*
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <net/rss_config.h>
#include <net/toeplitz.h>
#include <sys/systm.h>
uint32_t
toeplitz_hash(u_int keylen, const uint8_t *key, u_int datalen,
const uint8_t *data)
{
uint32_t hash = 0, v;
u_int i, b;
/* XXXRW: Perhaps an assertion about key length vs. data length? */
v = (key[0]<<24) + (key[1]<<16) + (key[2] <<8) + key[3];
for (i = 0; i < datalen; i++) {
for (b = 0; b < 8; b++) {
if (data[i] & (1<<(7-b)))
hash ^= v;
v <<= 1;
if ((i + 4) < RSS_KEYSIZE &&
(key[i+4] & (1<<(7-b))))
v |= 1;
}
}
return (hash);
}
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