in_cksum.c revision 330897
1/* $NetBSD: in_cksum.c,v 1.7 1997/09/02 13:18:15 thorpej Exp $ */ 2 3/*- 4 * SPDX-License-Identifier: BSD-4-Clause 5 * 6 * Copyright (c) 1988, 1992, 1993 7 * The Regents of the University of California. All rights reserved. 8 * Copyright (c) 1996 9 * Matt Thomas <matt@3am-software.com> 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the University of 22 * California, Berkeley and its contributors. 23 * 4. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 * 39 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93 40 */ 41 42#include <sys/cdefs.h> /* RCS ID & Copyright macro defns */ 43__FBSDID("$FreeBSD: stable/11/sys/amd64/amd64/in_cksum.c 330897 2018-03-14 03:19:51Z eadler $"); 44 45#include <sys/param.h> 46#include <sys/mbuf.h> 47#include <sys/systm.h> 48#include <netinet/in_systm.h> 49#include <netinet/in.h> 50#include <netinet/ip.h> 51#include <machine/in_cksum.h> 52 53/* 54 * Checksum routine for Internet Protocol family headers 55 * (Portable Alpha version). 56 * 57 * This routine is very heavily used in the network 58 * code and should be modified for each CPU to be as fast as possible. 59 */ 60 61#define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) 62#define REDUCE32 \ 63 { \ 64 q_util.q = sum; \ 65 sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \ 66 } 67#define REDUCE16 \ 68 { \ 69 q_util.q = sum; \ 70 l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \ 71 sum = l_util.s[0] + l_util.s[1]; \ 72 ADDCARRY(sum); \ 73 } 74 75static const u_int32_t in_masks[] = { 76 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/ 77 0x00000000, 0x000000FF, 0x0000FFFF, 0x00FFFFFF, /* offset 0 */ 78 0x00000000, 0x0000FF00, 0x00FFFF00, 0xFFFFFF00, /* offset 1 */ 79 0x00000000, 0x00FF0000, 0xFFFF0000, 0xFFFF0000, /* offset 2 */ 80 0x00000000, 0xFF000000, 0xFF000000, 0xFF000000, /* offset 3 */ 81}; 82 83union l_util { 84 u_int16_t s[2]; 85 u_int32_t l; 86}; 87union q_util { 88 u_int16_t s[4]; 89 u_int32_t l[2]; 90 u_int64_t q; 91}; 92 93static u_int64_t 94in_cksumdata(const void *buf, int len) 95{ 96 const u_int32_t *lw = (const u_int32_t *) buf; 97 u_int64_t sum = 0; 98 u_int64_t prefilled; 99 int offset; 100 union q_util q_util; 101 102 if ((3 & (long) lw) == 0 && len == 20) { 103 sum = (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3] + lw[4]; 104 REDUCE32; 105 return sum; 106 } 107 108 if ((offset = 3 & (long) lw) != 0) { 109 const u_int32_t *masks = in_masks + (offset << 2); 110 lw = (u_int32_t *) (((long) lw) - offset); 111 sum = *lw++ & masks[len >= 3 ? 3 : len]; 112 len -= 4 - offset; 113 if (len <= 0) { 114 REDUCE32; 115 return sum; 116 } 117 } 118#if 0 119 /* 120 * Force to cache line boundary. 121 */ 122 offset = 32 - (0x1f & (long) lw); 123 if (offset < 32 && len > offset) { 124 len -= offset; 125 if (4 & offset) { 126 sum += (u_int64_t) lw[0]; 127 lw += 1; 128 } 129 if (8 & offset) { 130 sum += (u_int64_t) lw[0] + lw[1]; 131 lw += 2; 132 } 133 if (16 & offset) { 134 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3]; 135 lw += 4; 136 } 137 } 138#endif 139 /* 140 * access prefilling to start load of next cache line. 141 * then add current cache line 142 * save result of prefilling for loop iteration. 143 */ 144 prefilled = lw[0]; 145 while ((len -= 32) >= 4) { 146 u_int64_t prefilling = lw[8]; 147 sum += prefilled + lw[1] + lw[2] + lw[3] 148 + lw[4] + lw[5] + lw[6] + lw[7]; 149 lw += 8; 150 prefilled = prefilling; 151 } 152 if (len >= 0) { 153 sum += prefilled + lw[1] + lw[2] + lw[3] 154 + lw[4] + lw[5] + lw[6] + lw[7]; 155 lw += 8; 156 } else { 157 len += 32; 158 } 159 while ((len -= 16) >= 0) { 160 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3]; 161 lw += 4; 162 } 163 len += 16; 164 while ((len -= 4) >= 0) { 165 sum += (u_int64_t) *lw++; 166 } 167 len += 4; 168 if (len > 0) 169 sum += (u_int64_t) (in_masks[len] & *lw); 170 REDUCE32; 171 return sum; 172} 173 174u_short 175in_addword(u_short a, u_short b) 176{ 177 u_int64_t sum = a + b; 178 179 ADDCARRY(sum); 180 return (sum); 181} 182 183u_short 184in_pseudo(u_int32_t a, u_int32_t b, u_int32_t c) 185{ 186 u_int64_t sum; 187 union q_util q_util; 188 union l_util l_util; 189 190 sum = (u_int64_t) a + b + c; 191 REDUCE16; 192 return (sum); 193} 194 195u_short 196in_cksum_skip(struct mbuf *m, int len, int skip) 197{ 198 u_int64_t sum = 0; 199 int mlen = 0; 200 int clen = 0; 201 caddr_t addr; 202 union q_util q_util; 203 union l_util l_util; 204 205 len -= skip; 206 for (; skip && m; m = m->m_next) { 207 if (m->m_len > skip) { 208 mlen = m->m_len - skip; 209 addr = mtod(m, caddr_t) + skip; 210 goto skip_start; 211 } else { 212 skip -= m->m_len; 213 } 214 } 215 216 for (; m && len; m = m->m_next) { 217 if (m->m_len == 0) 218 continue; 219 mlen = m->m_len; 220 addr = mtod(m, caddr_t); 221skip_start: 222 if (len < mlen) 223 mlen = len; 224 if ((clen ^ (long) addr) & 1) 225 sum += in_cksumdata(addr, mlen) << 8; 226 else 227 sum += in_cksumdata(addr, mlen); 228 229 clen += mlen; 230 len -= mlen; 231 } 232 REDUCE16; 233 return (~sum & 0xffff); 234} 235 236u_int in_cksum_hdr(const struct ip *ip) 237{ 238 u_int64_t sum = in_cksumdata(ip, sizeof(struct ip)); 239 union q_util q_util; 240 union l_util l_util; 241 REDUCE16; 242 return (~sum & 0xffff); 243} 244