FreeBSD/Linux Kernel Cross Reference
sys/net/toeplitz.c
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: releng/11.1/sys/net/toeplitz.c 277331 2015-01-18 18:06:40Z adrian $");
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
37 uint32_t
38 toeplitz_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 }
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