Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/powerpc/powerpc/in_cksum.c
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1 /* $FreeBSD: releng/12.0/sys/powerpc/powerpc/in_cksum.c 325966 2017-11-18 14:26:50Z pfg $ */ 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/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 75 static const u_int32_t in_masks[] = { 76 #if 0 77 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/ 78 0x00000000, 0x000000FF, 0x0000FFFF, 0x00FFFFFF, /* offset 0 */ 79 0x00000000, 0x0000FF00, 0x00FFFF00, 0xFFFFFF00, /* offset 1 */ 80 0x00000000, 0x00FF0000, 0xFFFF0000, 0xFFFF0000, /* offset 2 */ 81 0x00000000, 0xFF000000, 0xFF000000, 0xFF000000, /* offset 3 */ 82 #else 83 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/ 84 0x00000000, 0xFF000000, 0xFFFF0000, 0xFFFFFF00, /* offset 0 */ 85 0x00000000, 0x00FF0000, 0x00FFFF00, 0x00FFFFFF, /* offset 1 */ 86 0x00000000, 0x0000FF00, 0x0000FFFF, 0x0000FFFF, /* offset 2 */ 87 0x00000000, 0x000000FF, 0x000000FF, 0x000000FF, /* offset 3 */ 88 #endif 89 }; 90 91 union l_util { 92 u_int16_t s[2]; 93 u_int32_t l; 94 }; 95 union q_util { 96 u_int16_t s[4]; 97 u_int32_t l[2]; 98 u_int64_t q; 99 }; 100 101 static u_int64_t 102 in_cksumdata(const void *buf, int len) 103 { 104 const u_int32_t *lw = (const u_int32_t *) buf; 105 u_int64_t sum = 0; 106 u_int64_t prefilled; 107 int offset; 108 union q_util q_util; 109 110 if ((3 & (long) lw) == 0 && len == 20) { 111 sum = (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3] + lw[4]; 112 REDUCE32; 113 return sum; 114 } 115 116 if ((offset = 3 & (long) lw) != 0) { 117 const u_int32_t *masks = in_masks + (offset << 2); 118 lw = (u_int32_t *) (((long) lw) - offset); 119 sum = *lw++ & masks[len >= 3 ? 3 : len]; 120 len -= 4 - offset; 121 if (len <= 0) { 122 REDUCE32; 123 return sum; 124 } 125 } 126 #if 0 127 /* 128 * Force to cache line boundary. 129 */ 130 offset = 32 - (0x1f & (long) lw); 131 if (offset < 32 && len > offset) { 132 len -= offset; 133 if (4 & offset) { 134 sum += (u_int64_t) lw[0]; 135 lw += 1; 136 } 137 if (8 & offset) { 138 sum += (u_int64_t) lw[0] + lw[1]; 139 lw += 2; 140 } 141 if (16 & offset) { 142 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3]; 143 lw += 4; 144 } 145 } 146 #endif 147 /* 148 * access prefilling to start load of next cache line. 149 * then add current cache line 150 * save result of prefilling for loop iteration. 151 */ 152 prefilled = lw[0]; 153 while ((len -= 32) >= 4) { 154 u_int64_t prefilling = lw[8]; 155 sum += prefilled + lw[1] + lw[2] + lw[3] 156 + lw[4] + lw[5] + lw[6] + lw[7]; 157 lw += 8; 158 prefilled = prefilling; 159 } 160 if (len >= 0) { 161 sum += prefilled + lw[1] + lw[2] + lw[3] 162 + lw[4] + lw[5] + lw[6] + lw[7]; 163 lw += 8; 164 } else { 165 len += 32; 166 } 167 while ((len -= 16) >= 0) { 168 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3]; 169 lw += 4; 170 } 171 len += 16; 172 while ((len -= 4) >= 0) { 173 sum += (u_int64_t) *lw++; 174 } 175 len += 4; 176 if (len > 0) 177 sum += (u_int64_t) (in_masks[len] & *lw); 178 REDUCE32; 179 return sum; 180 } 181 182 u_short 183 in_addword(u_short a, u_short b) 184 { 185 u_int64_t sum = a + b; 186 187 ADDCARRY(sum); 188 return (sum); 189 } 190 191 u_short 192 in_pseudo(u_int32_t a, u_int32_t b, u_int32_t c) 193 { 194 u_int64_t sum; 195 union q_util q_util; 196 union l_util l_util; 197 198 sum = (u_int64_t) a + b + c; 199 REDUCE16; 200 return (sum); 201 } 202 203 u_short 204 in_cksum_skip(struct mbuf *m, int len, int skip) 205 { 206 u_int64_t sum = 0; 207 int mlen = 0; 208 int clen = 0; 209 caddr_t addr; 210 union q_util q_util; 211 union l_util l_util; 212 213 len -= skip; 214 for (; skip && m; m = m->m_next) { 215 if (m->m_len > skip) { 216 mlen = m->m_len - skip; 217 addr = mtod(m, caddr_t) + skip; 218 goto skip_start; 219 } else { 220 skip -= m->m_len; 221 } 222 } 223 224 for (; m && len; m = m->m_next) { 225 if (m->m_len == 0) 226 continue; 227 mlen = m->m_len; 228 addr = mtod(m, caddr_t); 229 skip_start: 230 if (len < mlen) 231 mlen = len; 232 233 if ((clen ^ (long) addr) & 1) 234 sum += in_cksumdata(addr, mlen) << 8; 235 else 236 sum += in_cksumdata(addr, mlen); 237 238 clen += mlen; 239 len -= mlen; 240 } 241 REDUCE16; 242 return (~sum & 0xffff); 243 } 244 245 u_int in_cksum_hdr(const struct ip *ip) 246 { 247 u_int64_t sum = in_cksumdata(ip, sizeof(struct ip)); 248 union q_util q_util; 249 union l_util l_util; 250 REDUCE16; 251 return (~sum & 0xffff); 252 }
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