1/*-
2 * Copyright (c) 2010 David Malone <dwmalone@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD$");
29
30#include <sys/types.h>
31
32#include <net/rss_config.h>
33#include <net/toeplitz.h>
34
35#include <sys/systm.h>
36
37uint32_t
38toeplitz_hash(u_int keylen, const uint8_t *key, u_int datalen,
39    const uint8_t *data)
40{
41	uint32_t hash = 0, v;
42	u_int i, b;
43
44	/* XXXRW: Perhaps an assertion about key length vs. data length? */
45
46	v = (key[0]<<24) + (key[1]<<16) + (key[2] <<8) + key[3];
47	for (i = 0; i < datalen; i++) {
48		for (b = 0; b < 8; b++) {
49			if (data[i] & (1<<(7-b)))
50				hash ^= v;
51			v <<= 1;
52			if ((i + 4) < RSS_KEYSIZE &&
53			    (key[i+4] & (1<<(7-b))))
54				v |= 1;
55		}
56	}
57	return (hash);
58}
59