1/* $NetBSD: in_cksum.c,v 1.7 1997/09/02 13:18:15 thorpej Exp $ */ 2 3/*- 4 * Copyright (c) 1988, 1992, 1993 5 * The Regents of the University of California. All rights reserved. 6 * Copyright (c) 1996 7 * Matt Thomas <matt@3am-software.com> 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by the University of 20 * California, Berkeley and its contributors. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93 38 */ 39 40#include <sys/cdefs.h> /* RCS ID & Copyright macro defns */ 41__FBSDID("$FreeBSD$"); 42 43#include <sys/param.h> 44#include <sys/mbuf.h> 45#include <sys/systm.h> 46#include <netinet/in_systm.h> 47#include <netinet/in.h> 48#include <netinet/ip.h> 49#include <machine/in_cksum.h> 50 51/* 52 * Checksum routine for Internet Protocol family headers 53 * (Portable Alpha version). 54 * 55 * This routine is very heavily used in the network 56 * code and should be modified for each CPU to be as fast as possible. 57 */ 58 59#define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) 60#define REDUCE32 \ 61 { \ 62 q_util.q = sum; \ 63 sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \ 64 } 65#define REDUCE16 \ 66 { \ 67 q_util.q = sum; \ 68 l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \ 69 sum = l_util.s[0] + l_util.s[1]; \ 70 ADDCARRY(sum); \ 71 } 72 73static const u_int32_t in_masks[] = { 74 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/ 75 0x00000000, 0x000000FF, 0x0000FFFF, 0x00FFFFFF, /* offset 0 */ 76 0x00000000, 0x0000FF00, 0x00FFFF00, 0xFFFFFF00, /* offset 1 */ 77 0x00000000, 0x00FF0000, 0xFFFF0000, 0xFFFF0000, /* offset 2 */ 78 0x00000000, 0xFF000000, 0xFF000000, 0xFF000000, /* offset 3 */ 79}; 80 81union l_util { 82 u_int16_t s[2]; 83 u_int32_t l; 84}; 85union q_util { 86 u_int16_t s[4]; 87 u_int32_t l[2]; 88 u_int64_t q; 89}; 90 91static u_int64_t 92in_cksumdata(const void *buf, int len) 93{ 94 const u_int32_t *lw = (const u_int32_t *) buf; 95 u_int64_t sum = 0; 96 u_int64_t prefilled; 97 int offset; 98 union q_util q_util; 99 100 if ((3 & (long) lw) == 0 && len == 20) { 101 sum = (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3] + lw[4]; 102 REDUCE32; 103 return sum; 104 } 105 106 if ((offset = 3 & (long) lw) != 0) { 107 const u_int32_t *masks = in_masks + (offset << 2); 108 lw = (u_int32_t *) (((long) lw) - offset); 109 sum = *lw++ & masks[len >= 3 ? 3 : len]; 110 len -= 4 - offset; 111 if (len <= 0) { 112 REDUCE32; 113 return sum; 114 } 115 } 116#if 0 117 /* 118 * Force to cache line boundary. 119 */ 120 offset = 32 - (0x1f & (long) lw); 121 if (offset < 32 && len > offset) { 122 len -= offset; 123 if (4 & offset) { 124 sum += (u_int64_t) lw[0]; 125 lw += 1; 126 } 127 if (8 & offset) { 128 sum += (u_int64_t) lw[0] + lw[1]; 129 lw += 2; 130 } 131 if (16 & offset) { 132 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3]; 133 lw += 4; 134 } 135 } 136#endif 137 /* 138 * access prefilling to start load of next cache line. 139 * then add current cache line 140 * save result of prefilling for loop iteration. 141 */ 142 prefilled = lw[0]; 143 while ((len -= 32) >= 4) { 144 u_int64_t prefilling = lw[8]; 145 sum += prefilled + lw[1] + lw[2] + lw[3] 146 + lw[4] + lw[5] + lw[6] + lw[7]; 147 lw += 8; 148 prefilled = prefilling; 149 } 150 if (len >= 0) { 151 sum += prefilled + lw[1] + lw[2] + lw[3] 152 + lw[4] + lw[5] + lw[6] + lw[7]; 153 lw += 8; 154 } else { 155 len += 32; 156 } 157 while ((len -= 16) >= 0) { 158 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3]; 159 lw += 4; 160 } 161 len += 16; 162 while ((len -= 4) >= 0) { 163 sum += (u_int64_t) *lw++; 164 } 165 len += 4; 166 if (len > 0) 167 sum += (u_int64_t) (in_masks[len] & *lw); 168 REDUCE32; 169 return sum; 170} 171 172u_short 173in_addword(u_short a, u_short b) 174{ 175 u_int64_t sum = a + b; 176 177 ADDCARRY(sum); 178 return (sum); 179} 180 181u_short 182in_pseudo(u_int32_t a, u_int32_t b, u_int32_t c) 183{ 184 u_int64_t sum; 185 union q_util q_util; 186 union l_util l_util; 187 188 sum = (u_int64_t) a + b + c; 189 REDUCE16; 190 return (sum); 191} 192 193u_short 194in_cksum_skip(struct mbuf *m, int len, int skip) 195{ 196 u_int64_t sum = 0; 197 int mlen = 0; 198 int clen = 0; 199 caddr_t addr; 200 union q_util q_util; 201 union l_util l_util; 202 203 len -= skip; 204 for (; skip && m; m = m->m_next) { 205 if (m->m_len > skip) { 206 mlen = m->m_len - skip; 207 addr = mtod(m, caddr_t) + skip; 208 goto skip_start; 209 } else { 210 skip -= m->m_len; 211 } 212 } 213 214 for (; m && len; m = m->m_next) { 215 if (m->m_len == 0) 216 continue; 217 mlen = m->m_len; 218 addr = mtod(m, caddr_t); 219skip_start: 220 if (len < mlen) 221 mlen = len; 222 if ((clen ^ (long) addr) & 1) 223 sum += in_cksumdata(addr, mlen) << 8; 224 else 225 sum += in_cksumdata(addr, mlen); 226 227 clen += mlen; 228 len -= mlen; 229 } 230 REDUCE16; 231 return (~sum & 0xffff); 232} 233 234u_int in_cksum_hdr(const struct ip *ip) 235{ 236 u_int64_t sum = in_cksumdata(ip, sizeof(struct ip)); 237 union q_util q_util; 238 union l_util l_util; 239 REDUCE16; 240 return (~sum & 0xffff); 241} 242