1/* $FreeBSD$ */ 2/* $NetBSD: in_cksum.c,v 1.7 1997/09/02 13:18:15 thorpej Exp $ */ 3 4/*- 5 * Copyright (c) 1988, 1992, 1993 6 * The Regents of the University of California. All rights reserved. 7 * Copyright (c) 1996 8 * Matt Thomas <matt@3am-software.com> 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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93 39 */ 40 41#include <sys/cdefs.h> /* RCS ID & Copyright macro defns */ 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#if 0 75 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/ 76 0x00000000, 0x000000FF, 0x0000FFFF, 0x00FFFFFF, /* offset 0 */ 77 0x00000000, 0x0000FF00, 0x00FFFF00, 0xFFFFFF00, /* offset 1 */ 78 0x00000000, 0x00FF0000, 0xFFFF0000, 0xFFFF0000, /* offset 2 */ 79 0x00000000, 0xFF000000, 0xFF000000, 0xFF000000, /* offset 3 */ 80#else 81 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/ 82 0x00000000, 0xFF000000, 0xFFFF0000, 0xFFFFFF00, /* offset 0 */ 83 0x00000000, 0x00FF0000, 0x00FFFF00, 0x00FFFFFF, /* offset 1 */ 84 0x00000000, 0x0000FF00, 0x0000FFFF, 0x0000FFFF, /* offset 2 */ 85 0x00000000, 0x000000FF, 0x000000FF, 0x000000FF, /* offset 3 */ 86#endif 87}; 88 89union l_util { 90 u_int16_t s[2]; 91 u_int32_t l; 92}; 93union q_util { 94 u_int16_t s[4]; 95 u_int32_t l[2]; 96 u_int64_t q; 97}; 98 99static u_int64_t 100in_cksumdata(const void *buf, int len) 101{ 102 const u_int32_t *lw = (const u_int32_t *) buf; 103 u_int64_t sum = 0; 104 u_int64_t prefilled; 105 int offset; 106 union q_util q_util; 107 108 if ((3 & (long) lw) == 0 && len == 20) { 109 sum = (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3] + lw[4]; 110 REDUCE32; 111 return sum; 112 } 113 114 if ((offset = 3 & (long) lw) != 0) { 115 const u_int32_t *masks = in_masks + (offset << 2); 116 lw = (u_int32_t *) (((long) lw) - offset); 117 sum = *lw++ & masks[len >= 3 ? 3 : len]; 118 len -= 4 - offset; 119 if (len <= 0) { 120 REDUCE32; 121 return sum; 122 } 123 } 124#if 0 125 /* 126 * Force to cache line boundary. 127 */ 128 offset = 32 - (0x1f & (long) lw); 129 if (offset < 32 && len > offset) { 130 len -= offset; 131 if (4 & offset) { 132 sum += (u_int64_t) lw[0]; 133 lw += 1; 134 } 135 if (8 & offset) { 136 sum += (u_int64_t) lw[0] + lw[1]; 137 lw += 2; 138 } 139 if (16 & offset) { 140 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3]; 141 lw += 4; 142 } 143 } 144#endif 145 /* 146 * access prefilling to start load of next cache line. 147 * then add current cache line 148 * save result of prefilling for loop iteration. 149 */ 150 prefilled = lw[0]; 151 while ((len -= 32) >= 4) { 152 u_int64_t prefilling = lw[8]; 153 sum += prefilled + lw[1] + lw[2] + lw[3] 154 + lw[4] + lw[5] + lw[6] + lw[7]; 155 lw += 8; 156 prefilled = prefilling; 157 } 158 if (len >= 0) { 159 sum += prefilled + lw[1] + lw[2] + lw[3] 160 + lw[4] + lw[5] + lw[6] + lw[7]; 161 lw += 8; 162 } else { 163 len += 32; 164 } 165 while ((len -= 16) >= 0) { 166 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3]; 167 lw += 4; 168 } 169 len += 16; 170 while ((len -= 4) >= 0) { 171 sum += (u_int64_t) *lw++; 172 } 173 len += 4; 174 if (len > 0) 175 sum += (u_int64_t) (in_masks[len] & *lw); 176 REDUCE32; 177 return sum; 178} 179 180u_short 181in_addword(u_short a, u_short b) 182{ 183 u_int64_t sum = a + b; 184 185 ADDCARRY(sum); 186 return (sum); 187} 188 189u_short 190in_pseudo(u_int32_t a, u_int32_t b, u_int32_t c) 191{ 192 u_int64_t sum; 193 union q_util q_util; 194 union l_util l_util; 195 196 sum = (u_int64_t) a + b + c; 197 REDUCE16; 198 return (sum); 199} 200 201u_short 202in_cksum_skip(struct mbuf *m, int len, int skip) 203{ 204 u_int64_t sum = 0; 205 int mlen = 0; 206 int clen = 0; 207 caddr_t addr; 208 union q_util q_util; 209 union l_util l_util; 210 211 len -= skip; 212 for (; skip && m; m = m->m_next) { 213 if (m->m_len > skip) { 214 mlen = m->m_len - skip; 215 addr = mtod(m, caddr_t) + skip; 216 goto skip_start; 217 } else { 218 skip -= m->m_len; 219 } 220 } 221 222 for (; m && len; m = m->m_next) { 223 if (m->m_len == 0) 224 continue; 225 mlen = m->m_len; 226 addr = mtod(m, caddr_t); 227skip_start: 228 if (len < mlen) 229 mlen = len; 230 231 if ((clen ^ (long) addr) & 1) 232 sum += in_cksumdata(addr, mlen) << 8; 233 else 234 sum += in_cksumdata(addr, mlen); 235 236 clen += mlen; 237 len -= mlen; 238 } 239 REDUCE16; 240 return (~sum & 0xffff); 241} 242 243u_int in_cksum_hdr(const struct ip *ip) 244{ 245 u_int64_t sum = in_cksumdata(ip, sizeof(struct ip)); 246 union q_util q_util; 247 union l_util l_util; 248 REDUCE16; 249 return (~sum & 0xffff); 250} 251