1/* $FreeBSD$ */ 2/* $NetBSD: in_cksum.c,v 1.7 1997/09/02 13:18:15 thorpej Exp $ */ 3 4/*- 5 * SPDX-License-Identifier: BSD-4-Clause 6 * 7 * Copyright (c) 1988, 1992, 1993 8 * The Regents of the University of California. All rights reserved. 9 * Copyright (c) 1996 10 * Matt Thomas <matt@3am-software.com> 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. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the University of 23 * California, Berkeley and its contributors. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93 41 */ 42 43#include <sys/cdefs.h> /* RCS ID & Copyright macro defns */ 44 45#include <sys/endian.h> 46#include <sys/param.h> 47#include <sys/mbuf.h> 48#include <sys/systm.h> 49#include <netinet/in_systm.h> 50#include <netinet/in.h> 51#include <netinet/ip.h> 52#include <machine/in_cksum.h> 53 54/* 55 * Checksum routine for Internet Protocol family headers 56 * (Portable Alpha version). 57 * 58 * This routine is very heavily used in the network 59 * code and should be modified for each CPU to be as fast as possible. 60 */ 61 62#define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) 63#define REDUCE32 \ 64 { \ 65 q_util.q = sum; \ 66 sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \ 67 } 68#define REDUCE16 \ 69 { \ 70 q_util.q = sum; \ 71 l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \ 72 sum = l_util.s[0] + l_util.s[1]; \ 73 ADDCARRY(sum); \ 74 } 75 76static const u_int32_t in_masks[] = { 77#if _BYTE_ORDER == _LITTLE_ENDIAN 78 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/ 79 0x00000000, 0x000000FF, 0x0000FFFF, 0x00FFFFFF, /* offset 0 */ 80 0x00000000, 0x0000FF00, 0x00FFFF00, 0xFFFFFF00, /* offset 1 */ 81 0x00000000, 0x00FF0000, 0xFFFF0000, 0xFFFF0000, /* offset 2 */ 82 0x00000000, 0xFF000000, 0xFF000000, 0xFF000000, /* offset 3 */ 83#else 84 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/ 85 0x00000000, 0xFF000000, 0xFFFF0000, 0xFFFFFF00, /* offset 0 */ 86 0x00000000, 0x00FF0000, 0x00FFFF00, 0x00FFFFFF, /* offset 1 */ 87 0x00000000, 0x0000FF00, 0x0000FFFF, 0x0000FFFF, /* offset 2 */ 88 0x00000000, 0x000000FF, 0x000000FF, 0x000000FF, /* offset 3 */ 89#endif 90}; 91 92union l_util { 93 u_int16_t s[2]; 94 u_int32_t l; 95}; 96union q_util { 97 u_int16_t s[4]; 98 u_int32_t l[2]; 99 u_int64_t q; 100}; 101 102static u_int64_t 103in_cksumdata(const void *buf, int len) 104{ 105 const u_int32_t *lw = (const u_int32_t *) buf; 106 u_int64_t sum = 0; 107 u_int64_t prefilled; 108 int offset; 109 union q_util q_util; 110 111 if ((3 & (long) lw) == 0 && len == 20) { 112 sum = (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3] + lw[4]; 113 REDUCE32; 114 return sum; 115 } 116 117 if ((offset = 3 & (long) lw) != 0) { 118 const u_int32_t *masks = in_masks + (offset << 2); 119 lw = (u_int32_t *) (((long) lw) - offset); 120 sum = *lw++ & masks[len >= 3 ? 3 : len]; 121 len -= 4 - offset; 122 if (len <= 0) { 123 REDUCE32; 124 return sum; 125 } 126 } 127#if 0 128 /* 129 * Force to cache line boundary. 130 */ 131 offset = 32 - (0x1f & (long) lw); 132 if (offset < 32 && len > offset) { 133 len -= offset; 134 if (4 & offset) { 135 sum += (u_int64_t) lw[0]; 136 lw += 1; 137 } 138 if (8 & offset) { 139 sum += (u_int64_t) lw[0] + lw[1]; 140 lw += 2; 141 } 142 if (16 & offset) { 143 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3]; 144 lw += 4; 145 } 146 } 147#endif 148 /* 149 * access prefilling to start load of next cache line. 150 * then add current cache line 151 * save result of prefilling for loop iteration. 152 */ 153 prefilled = lw[0]; 154 while ((len -= 32) >= 4) { 155 u_int64_t prefilling = lw[8]; 156 sum += prefilled + lw[1] + lw[2] + lw[3] 157 + lw[4] + lw[5] + lw[6] + lw[7]; 158 lw += 8; 159 prefilled = prefilling; 160 } 161 if (len >= 0) { 162 sum += prefilled + lw[1] + lw[2] + lw[3] 163 + lw[4] + lw[5] + lw[6] + lw[7]; 164 lw += 8; 165 } else { 166 len += 32; 167 } 168 while ((len -= 16) >= 0) { 169 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3]; 170 lw += 4; 171 } 172 len += 16; 173 while ((len -= 4) >= 0) { 174 sum += (u_int64_t) *lw++; 175 } 176 len += 4; 177 if (len > 0) 178 sum += (u_int64_t) (in_masks[len] & *lw); 179 REDUCE32; 180 return sum; 181} 182 183u_short 184in_addword(u_short a, u_short b) 185{ 186 u_int64_t sum = a + b; 187 188 ADDCARRY(sum); 189 return (sum); 190} 191 192u_short 193in_pseudo(u_int32_t a, u_int32_t b, u_int32_t c) 194{ 195 u_int64_t sum; 196 union q_util q_util; 197 union l_util l_util; 198 199 sum = (u_int64_t) a + b + c; 200 REDUCE16; 201 return (sum); 202} 203 204u_short 205in_cksum_skip(struct mbuf *m, int len, int skip) 206{ 207 u_int64_t sum = 0; 208 int mlen = 0; 209 int clen = 0; 210 caddr_t addr; 211 union q_util q_util; 212 union l_util l_util; 213 214 len -= skip; 215 for (; skip && m; m = m->m_next) { 216 if (m->m_len > skip) { 217 mlen = m->m_len - skip; 218 addr = mtod(m, caddr_t) + skip; 219 goto skip_start; 220 } else { 221 skip -= m->m_len; 222 } 223 } 224 225 for (; m && len; m = m->m_next) { 226 if (m->m_len == 0) 227 continue; 228 mlen = m->m_len; 229 addr = mtod(m, caddr_t); 230skip_start: 231 if (len < mlen) 232 mlen = len; 233 234 if ((clen ^ (long) addr) & 1) 235 sum += in_cksumdata(addr, mlen) << 8; 236 else 237 sum += in_cksumdata(addr, mlen); 238 239 clen += mlen; 240 len -= mlen; 241 } 242 REDUCE16; 243 return (~sum & 0xffff); 244} 245 246u_int in_cksum_hdr(const struct ip *ip) 247{ 248 u_int64_t sum = in_cksumdata(ip, sizeof(struct ip)); 249 union q_util q_util; 250 union l_util l_util; 251 REDUCE16; 252 return (~sum & 0xffff); 253} 254