1/* $FreeBSD$ */ 2/* $OpenBSD: in4_cksum.c,v 1.7 2003/06/02 23:28:13 millert Exp $ */ 3/* $KAME: in4_cksum.c,v 1.10 2001/11/30 10:06:15 itojun Exp $ */ 4/* $NetBSD: in_cksum.c,v 1.13 1996/10/13 02:03:03 christos Exp $ */ 5 6/*- 7 * SPDX-License-Identifier: BSD-3-Clause 8 * 9 * Copyright (C) 1999 WIDE Project. 10 * All rights reserved. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the project nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37/* 38 * Copyright (c) 1988, 1992, 1993 39 * The Regents of the University of California. All rights reserved. 40 * 41 * Redistribution and use in source and binary forms, with or without 42 * modification, are permitted provided that the following conditions 43 * are met: 44 * 1. Redistributions of source code must retain the above copyright 45 * notice, this list of conditions and the following disclaimer. 46 * 2. Redistributions in binary form must reproduce the above copyright 47 * notice, this list of conditions and the following disclaimer in the 48 * documentation and/or other materials provided with the distribution. 49 * 3. Neither the name of the University nor the names of its contributors 50 * may be used to endorse or promote products derived from this software 51 * without specific prior written permission. 52 * 53 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 54 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 55 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 56 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 57 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 58 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 59 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 60 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 61 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 62 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 63 * SUCH DAMAGE. 64 * 65 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93 66 */ 67 68#include <sys/param.h> 69#include <sys/systm.h> 70#include <sys/mbuf.h> 71 72#include <netinet/in.h> 73#include <netinet/in_systm.h> 74#include <netinet/ip.h> 75#include <netinet/ip_var.h> 76 77#include <machine/in_cksum.h> 78 79#define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) 80#define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; (void)ADDCARRY(sum);} 81 82int in4_cksum(struct mbuf *, u_int8_t, int, int); 83 84int 85in4_cksum(struct mbuf *m, u_int8_t nxt, int off, int len) 86{ 87 union { 88 struct ipovly ipov; 89 u_int16_t w[10]; 90 } u; 91 union { 92 u_int16_t s[2]; 93 u_int32_t l; 94 } l_util; 95 96 u_int16_t *w; 97 int psum; 98 int sum = 0; 99 100 if (nxt != 0) { 101 /* pseudo header */ 102 if (off < sizeof(struct ipovly)) 103 panic("in4_cksum: offset too short"); 104 if (m->m_len < sizeof(struct ip)) 105 panic("in4_cksum: bad mbuf chain"); 106 bzero(&u.ipov, sizeof(u.ipov)); 107 u.ipov.ih_len = htons(len); 108 u.ipov.ih_pr = nxt; 109 u.ipov.ih_src = mtod(m, struct ip *)->ip_src; 110 u.ipov.ih_dst = mtod(m, struct ip *)->ip_dst; 111 w = u.w; 112 /* assumes sizeof(ipov) == 20 */ 113 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; sum += w[4]; 114 sum += w[5]; sum += w[6]; sum += w[7]; sum += w[8]; sum += w[9]; 115 } 116 117 psum = in_cksum_skip(m, len + off, off); 118 psum = ~psum & 0xffff; 119 sum += psum; 120 REDUCE; 121 return (~sum & 0xffff); 122} 123