1 /* $NetBSD: cksum.c,v 1.2 2008/04/28 20:23:15 martin Exp $ */ 2 3 /* 4 * Copyright (c) 1999 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Julian Coleman, Waldi Ravens and Leo Weppelman. 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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include "privahdi.h" 33 34 /* 35 * Disklabel checksum. 36 */ 37 38 int 39 dkcksum (dl) 40 struct disklabel *dl; 41 { 42 u_short *start, *end, sum = 0; 43 44 start = (u_short *)dl; 45 end = (u_short *)&dl->d_partitions[dl->d_npartitions]; 46 while (start < end) 47 sum ^= *start++; 48 return (sum); 49 } 50 51 /* 52 * AHDI root sector checksum. 53 */ 54 55 u_int16_t 56 ahdi_cksum (buf) 57 void *buf; 58 { 59 u_int16_t *p = (u_int16_t *)buf; 60 u_int16_t csum = 0; 61 int i; 62 63 for (i = 0; i < 256; i++) 64 csum += *p++; 65 return ((0x1234 - csum) & 0xffff); 66 } 67