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 __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 * These implementations may be overridden on a per-platform basis. On 53 * platforms with a direct map, the implementation of in_cksum() must handle 54 * unmapped mbufs. 55 */ 56 #ifndef HAVE_MD_IN_CKSUM 57 58 /* 59 * Checksum routine for Internet Protocol family headers 60 * (Portable Alpha version). 61 * 62 * This routine is very heavily used in the network 63 * code and should be modified for each CPU to be as fast as possible. 64 */ 65 66 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) 67 #define REDUCE32 \ 68 { \ 69 q_util.q = sum; \ 70 sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \ 71 } 72 #define REDUCE16 \ 73 { \ 74 q_util.q = sum; \ 75 l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \ 76 sum = l_util.s[0] + l_util.s[1]; \ 77 ADDCARRY(sum); \ 78 } 79 80 static const u_int32_t in_masks[] = { 81 #if _BYTE_ORDER == _LITTLE_ENDIAN 82 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/ 83 0x00000000, 0x000000FF, 0x0000FFFF, 0x00FFFFFF, /* offset 0 */ 84 0x00000000, 0x0000FF00, 0x00FFFF00, 0xFFFFFF00, /* offset 1 */ 85 0x00000000, 0x00FF0000, 0xFFFF0000, 0xFFFF0000, /* offset 2 */ 86 0x00000000, 0xFF000000, 0xFF000000, 0xFF000000, /* offset 3 */ 87 #else 88 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/ 89 0x00000000, 0xFF000000, 0xFFFF0000, 0xFFFFFF00, /* offset 0 */ 90 0x00000000, 0x00FF0000, 0x00FFFF00, 0x00FFFFFF, /* offset 1 */ 91 0x00000000, 0x0000FF00, 0x0000FFFF, 0x0000FFFF, /* offset 2 */ 92 0x00000000, 0x000000FF, 0x000000FF, 0x000000FF, /* offset 3 */ 93 #endif 94 }; 95 96 union l_util { 97 u_int16_t s[2]; 98 u_int32_t l; 99 }; 100 union q_util { 101 u_int16_t s[4]; 102 u_int32_t l[2]; 103 u_int64_t q; 104 }; 105 106 static u_int64_t 107 in_cksumdata(const void *buf, int len) 108 { 109 const u_int32_t *lw = (const u_int32_t *) buf; 110 u_int64_t sum = 0; 111 u_int64_t prefilled; 112 int offset; 113 union q_util q_util; 114 115 if ((3 & (long) lw) == 0 && len == 20) { 116 sum = (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3] + lw[4]; 117 REDUCE32; 118 return sum; 119 } 120 121 if ((offset = 3 & (long) lw) != 0) { 122 const u_int32_t *masks = in_masks + (offset << 2); 123 lw = (u_int32_t *) (((long) lw) - offset); 124 sum = *lw++ & masks[len >= 3 ? 3 : len]; 125 len -= 4 - offset; 126 if (len <= 0) { 127 REDUCE32; 128 return sum; 129 } 130 } 131 #if 0 132 /* 133 * Force to cache line boundary. 134 */ 135 offset = 32 - (0x1f & (long) lw); 136 if (offset < 32 && len > offset) { 137 len -= offset; 138 if (4 & offset) { 139 sum += (u_int64_t) lw[0]; 140 lw += 1; 141 } 142 if (8 & offset) { 143 sum += (u_int64_t) lw[0] + lw[1]; 144 lw += 2; 145 } 146 if (16 & offset) { 147 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3]; 148 lw += 4; 149 } 150 } 151 #endif 152 /* 153 * access prefilling to start load of next cache line. 154 * then add current cache line 155 * save result of prefilling for loop iteration. 156 */ 157 prefilled = lw[0]; 158 while ((len -= 32) >= 4) { 159 u_int64_t prefilling = lw[8]; 160 sum += prefilled + lw[1] + lw[2] + lw[3] 161 + lw[4] + lw[5] + lw[6] + lw[7]; 162 lw += 8; 163 prefilled = prefilling; 164 } 165 if (len >= 0) { 166 sum += prefilled + lw[1] + lw[2] + lw[3] 167 + lw[4] + lw[5] + lw[6] + lw[7]; 168 lw += 8; 169 } else { 170 len += 32; 171 } 172 while ((len -= 16) >= 0) { 173 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3]; 174 lw += 4; 175 } 176 len += 16; 177 while ((len -= 4) >= 0) { 178 sum += (u_int64_t) *lw++; 179 } 180 len += 4; 181 if (len > 0) 182 sum += (u_int64_t) (in_masks[len] & *lw); 183 REDUCE32; 184 return sum; 185 } 186 187 u_short 188 in_addword(u_short a, u_short b) 189 { 190 u_int64_t sum = a + b; 191 192 ADDCARRY(sum); 193 return (sum); 194 } 195 196 u_short 197 in_pseudo(u_int32_t a, u_int32_t b, u_int32_t c) 198 { 199 u_int64_t sum; 200 union q_util q_util; 201 union l_util l_util; 202 203 sum = (u_int64_t) a + b + c; 204 REDUCE16; 205 return (sum); 206 } 207 208 struct cksum_skip_partial_args { 209 uint64_t csum; 210 int clen; 211 }; 212 213 static int 214 in_cksum_skip_partial(void *arg, void *data, u_int len) 215 { 216 struct cksum_skip_partial_args *a; 217 218 a = arg; 219 if (((uintptr_t)data ^ a->clen) & 1) 220 a->csum += in_cksumdata(data, len) << 8; 221 else 222 a->csum += in_cksumdata(data, len); 223 a->clen += len; 224 return (0); 225 } 226 227 u_short 228 in_cksum_skip(struct mbuf *m, int len, int skip) 229 { 230 struct cksum_skip_partial_args a; 231 union q_util q_util; 232 union l_util l_util; 233 uint64_t sum; 234 235 len -= skip; 236 237 /* 238 * The use of m_apply() allows this routine to operate on unmapped 239 * mbufs. 240 */ 241 a.csum = 0; 242 a.clen = 0; 243 (void)m_apply(m, skip, len, in_cksum_skip_partial, &a); 244 sum = a.csum; 245 REDUCE16; 246 return (~sum & 0xffff); 247 } 248 249 u_int in_cksum_hdr(const struct ip *ip) 250 { 251 u_int64_t sum = in_cksumdata(ip, sizeof(struct ip)); 252 union q_util q_util; 253 union l_util l_util; 254 REDUCE16; 255 return (~sum & 0xffff); 256 } 257 258 #endif /* !HAVE_MD_IN_CKSUM */ 259