1 /*- 2 * SPDX-License-Identifier: BSD-4-Clause 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> 41 #include <sys/param.h> 42 #include <sys/mbuf.h> 43 #include <sys/systm.h> 44 #include <netinet/in_systm.h> 45 #include <netinet/in.h> 46 #include <netinet/ip.h> 47 #include <machine/in_cksum.h> 48 49 /* 50 * These implementations may be overridden on a per-platform basis. On 51 * platforms with a direct map, the implementation of in_cksum() must handle 52 * unmapped mbufs. 53 */ 54 #ifndef HAVE_MD_IN_CKSUM 55 56 /* 57 * Checksum routine for Internet Protocol family headers 58 * (Portable Alpha version). 59 * 60 * This routine is very heavily used in the network 61 * code and should be modified for each CPU to be as fast as possible. 62 */ 63 64 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) 65 #define REDUCE32 \ 66 { \ 67 q_util.q = sum; \ 68 sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \ 69 } 70 #define REDUCE16 \ 71 { \ 72 q_util.q = sum; \ 73 l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \ 74 sum = l_util.s[0] + l_util.s[1]; \ 75 ADDCARRY(sum); \ 76 } 77 78 static const u_int32_t in_masks[] = { 79 #if _BYTE_ORDER == _LITTLE_ENDIAN 80 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/ 81 0x00000000, 0x000000FF, 0x0000FFFF, 0x00FFFFFF, /* offset 0 */ 82 0x00000000, 0x0000FF00, 0x00FFFF00, 0xFFFFFF00, /* offset 1 */ 83 0x00000000, 0x00FF0000, 0xFFFF0000, 0xFFFF0000, /* offset 2 */ 84 0x00000000, 0xFF000000, 0xFF000000, 0xFF000000, /* offset 3 */ 85 #else 86 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/ 87 0x00000000, 0xFF000000, 0xFFFF0000, 0xFFFFFF00, /* offset 0 */ 88 0x00000000, 0x00FF0000, 0x00FFFF00, 0x00FFFFFF, /* offset 1 */ 89 0x00000000, 0x0000FF00, 0x0000FFFF, 0x0000FFFF, /* offset 2 */ 90 0x00000000, 0x000000FF, 0x000000FF, 0x000000FF, /* offset 3 */ 91 #endif 92 }; 93 94 union l_util { 95 u_int16_t s[2]; 96 u_int32_t l; 97 }; 98 union q_util { 99 u_int16_t s[4]; 100 u_int32_t l[2]; 101 u_int64_t q; 102 }; 103 104 static u_int64_t 105 in_cksumdata(const void *buf, int len) 106 { 107 const u_int32_t *lw = (const u_int32_t *) buf; 108 u_int64_t sum = 0; 109 u_int64_t prefilled; 110 int offset; 111 union q_util q_util; 112 113 if ((3 & (long) lw) == 0 && len == 20) { 114 sum = (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3] + lw[4]; 115 REDUCE32; 116 return sum; 117 } 118 119 if ((offset = 3 & (long) lw) != 0) { 120 const u_int32_t *masks = in_masks + (offset << 2); 121 lw = (u_int32_t *) (((long) lw) - offset); 122 sum = *lw++ & masks[len >= 3 ? 3 : len]; 123 len -= 4 - offset; 124 if (len <= 0) { 125 REDUCE32; 126 return sum; 127 } 128 } 129 #if 0 130 /* 131 * Force to cache line boundary. 132 */ 133 offset = 32 - (0x1f & (long) lw); 134 if (offset < 32 && len > offset) { 135 len -= offset; 136 if (4 & offset) { 137 sum += (u_int64_t) lw[0]; 138 lw += 1; 139 } 140 if (8 & offset) { 141 sum += (u_int64_t) lw[0] + lw[1]; 142 lw += 2; 143 } 144 if (16 & offset) { 145 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3]; 146 lw += 4; 147 } 148 } 149 #endif 150 /* 151 * access prefilling to start load of next cache line. 152 * then add current cache line 153 * save result of prefilling for loop iteration. 154 */ 155 prefilled = lw[0]; 156 while ((len -= 32) >= 4) { 157 u_int64_t prefilling = lw[8]; 158 sum += prefilled + lw[1] + lw[2] + lw[3] 159 + lw[4] + lw[5] + lw[6] + lw[7]; 160 lw += 8; 161 prefilled = prefilling; 162 } 163 if (len >= 0) { 164 sum += prefilled + lw[1] + lw[2] + lw[3] 165 + lw[4] + lw[5] + lw[6] + lw[7]; 166 lw += 8; 167 } else { 168 len += 32; 169 } 170 while ((len -= 16) >= 0) { 171 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3]; 172 lw += 4; 173 } 174 len += 16; 175 while ((len -= 4) >= 0) { 176 sum += (u_int64_t) *lw++; 177 } 178 len += 4; 179 if (len > 0) 180 sum += (u_int64_t) (in_masks[len] & *lw); 181 REDUCE32; 182 return sum; 183 } 184 185 u_short 186 in_addword(u_short a, u_short b) 187 { 188 u_int64_t sum = a + b; 189 190 ADDCARRY(sum); 191 return (sum); 192 } 193 194 u_short 195 in_pseudo(u_int32_t a, u_int32_t b, u_int32_t c) 196 { 197 u_int64_t sum; 198 union q_util q_util; 199 union l_util l_util; 200 201 sum = (u_int64_t) a + b + c; 202 REDUCE16; 203 return (sum); 204 } 205 206 struct cksum_skip_partial_args { 207 uint64_t csum; 208 int clen; 209 }; 210 211 static int 212 in_cksum_skip_partial(void *arg, void *data, u_int len) 213 { 214 struct cksum_skip_partial_args *a; 215 216 a = arg; 217 if (((uintptr_t)data ^ a->clen) & 1) 218 a->csum += in_cksumdata(data, len) << 8; 219 else 220 a->csum += in_cksumdata(data, len); 221 a->clen += len; 222 return (0); 223 } 224 225 u_short 226 in_cksum_skip(struct mbuf *m, int len, int skip) 227 { 228 struct cksum_skip_partial_args a; 229 union q_util q_util; 230 union l_util l_util; 231 uint64_t sum; 232 233 len -= skip; 234 235 /* 236 * The use of m_apply() allows this routine to operate on unmapped 237 * mbufs. 238 */ 239 a.csum = 0; 240 a.clen = 0; 241 (void)m_apply(m, skip, len, in_cksum_skip_partial, &a); 242 sum = a.csum; 243 REDUCE16; 244 return (~sum & 0xffff); 245 } 246 247 u_int in_cksum_hdr(const struct ip *ip) 248 { 249 u_int64_t sum = in_cksumdata(ip, sizeof(struct ip)); 250 union q_util q_util; 251 union l_util l_util; 252 REDUCE16; 253 return (~sum & 0xffff); 254 } 255 256 #endif /* !HAVE_MD_IN_CKSUM */ 257