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review.coreboot.org / coreboot / a50ced2eba20a007fa5b486c251c252ad09868cf / . / payloads / libpayload / libc / ipchecksum.c
blob: 8d67921b0378e6f6a80fd4a5b44f6f683ed49829 [file] [log] [blame]
Uwe Hermannc52761b2008-03-20 00:02:07 +0000[diff] [blame]1/*
Uwe Hermann6a441bf2008-03-20 19:54:59 +0000[diff] [blame]2 * This file is part of the libpayload project.
3 *
Uwe Hermann661e3802008-03-21 18:37:23 +0000[diff] [blame]4 * It has originally been taken from the FreeBSD project.
Uwe Hermannc52761b2008-03-20 00:02:07 +0000[diff] [blame]5 *
6 * Copyright (c) 2001 Charles Mott <cm@linktel.net>
Stefan Reinauer11e45cd2008-08-16 15:16:36 +0000[diff] [blame]7 * Copyright (c) 2008 coresystems GmbH
Uwe Hermannc52761b2008-03-20 00:02:07 +0000[diff] [blame]8 * All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <libpayload.h>
33
Stefan Reinauer11e45cd2008-08-16 15:16:36 +0000[diff] [blame]34unsigned short ipchksum(const void *vptr, unsigned long nbytes)
Uwe Hermannc52761b2008-03-20 00:02:07 +0000[diff] [blame]35{
Uwe Hermann6a441bf2008-03-20 19:54:59 +0000[diff] [blame]36 int sum, oddbyte;
Stefan Reinauer11e45cd2008-08-16 15:16:36 +0000[diff] [blame]37 const unsigned short *ptr = vptr;
Uwe Hermannc52761b2008-03-20 00:02:07 +0000[diff] [blame]38
Uwe Hermann6a441bf2008-03-20 19:54:59 +0000[diff] [blame]39 sum = 0;
40 while (nbytes > 1) {
41 sum += *ptr++;
42 nbytes -= 2;
43 }
44 if (nbytes == 1) {
45 oddbyte = 0;
46 ((u8 *) & oddbyte)[0] = *(u8 *) ptr;
47 ((u8 *) & oddbyte)[1] = 0;
48 sum += oddbyte;
49 }
50 sum = (sum >> 16) + (sum & 0xffff);
51 sum += (sum >> 16);
52 return (~sum);
Uwe Hermannc52761b2008-03-20 00:02:07 +0000[diff] [blame]53}