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 38 #include <sys/cdefs.h> 39 #include <sys/param.h> 40 #include <sys/mbuf.h> 41 #include <sys/systm.h> 42 #include <netinet/in_systm.h> 43 #include <netinet/in.h> 44 #include <netinet/ip.h> 45 #include <machine/in_cksum.h> 46 47 /* 48 * These implementations may be overridden on a per-platform basis. On 49 * platforms with a direct map, the implementation of in_cksum() must handle 50 * unmapped mbufs. 51 */ 52 #ifndef HAVE_MD_IN_CKSUM 53 54 /* 55 * Checksum routine for Internet Protocol family headers 56 * (Portable Alpha version). 57 * 58 * This routine is very heavily used in the network 59 * code and should be modified for each CPU to be as fast as possible. 60 */ 61 62 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) 63 #define REDUCE32 \ 64 { \ 65 q_util.q = sum; \ 66 sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \ 67 } 68 #define REDUCE16 \ 69 { \ 70 q_util.q = sum; \ 71 l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \ 72 sum = l_util.s[0] + l_util.s[1]; \ 73 ADDCARRY(sum); \ 74 } 75 76 static const u_int32_t in_masks[] = { 77 #if _BYTE_ORDER == _LITTLE_ENDIAN 78 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/ 79 0x00000000, 0x000000FF, 0x0000FFFF, 0x00FFFFFF, /* offset 0 */ 80 0x00000000, 0x0000FF00, 0x00FFFF00, 0xFFFFFF00, /* offset 1 */ 81 0x00000000, 0x00FF0000, 0xFFFF0000, 0xFFFF0000, /* offset 2 */ 82 0x00000000, 0xFF000000, 0xFF000000, 0xFF000000, /* offset 3 */ 83 #else 84 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/ 85 0x00000000, 0xFF000000, 0xFFFF0000, 0xFFFFFF00, /* offset 0 */ 86 0x00000000, 0x00FF0000, 0x00FFFF00, 0x00FFFFFF, /* offset 1 */ 87 0x00000000, 0x0000FF00, 0x0000FFFF, 0x0000FFFF, /* offset 2 */ 88 0x00000000, 0x000000FF, 0x000000FF, 0x000000FF, /* offset 3 */ 89 #endif 90 }; 91 92 union l_util { 93 u_int16_t s[2]; 94 u_int32_t l; 95 }; 96 union q_util { 97 u_int16_t s[4]; 98 u_int32_t l[2]; 99 u_int64_t q; 100 }; 101 102 static u_int64_t 103 in_cksumdata(const void *buf, int len) 104 { 105 const u_int32_t *lw = (const u_int32_t *) buf; 106 u_int64_t sum = 0; 107 u_int64_t prefilled; 108 int offset; 109 union q_util q_util; 110 111 if ((3 & (long) lw) == 0 && len == 20) { 112 sum = (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3] + lw[4]; 113 REDUCE32; 114 return sum; 115 } 116 117 if ((offset = 3 & (long) lw) != 0) { 118 const u_int32_t *masks = in_masks + (offset << 2); 119 lw = (u_int32_t *) (((long) lw) - offset); 120 sum = *lw++ & masks[len >= 3 ? 3 : len]; 121 len -= 4 - offset; 122 if (len <= 0) { 123 REDUCE32; 124 return sum; 125 } 126 } 127 #if 0 128 /* 129 * Force to cache line boundary. 130 */ 131 offset = 32 - (0x1f & (long) lw); 132 if (offset < 32 && len > offset) { 133 len -= offset; 134 if (4 & offset) { 135 sum += (u_int64_t) lw[0]; 136 lw += 1; 137 } 138 if (8 & offset) { 139 sum += (u_int64_t) lw[0] + lw[1]; 140 lw += 2; 141 } 142 if (16 & offset) { 143 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3]; 144 lw += 4; 145 } 146 } 147 #endif 148 /* 149 * access prefilling to start load of next cache line. 150 * then add current cache line 151 * save result of prefilling for loop iteration. 152 */ 153 prefilled = lw[0]; 154 while ((len -= 32) >= 4) { 155 u_int64_t prefilling = lw[8]; 156 sum += prefilled + lw[1] + lw[2] + lw[3] 157 + lw[4] + lw[5] + lw[6] + lw[7]; 158 lw += 8; 159 prefilled = prefilling; 160 } 161 if (len >= 0) { 162 sum += prefilled + lw[1] + lw[2] + lw[3] 163 + lw[4] + lw[5] + lw[6] + lw[7]; 164 lw += 8; 165 } else { 166 len += 32; 167 } 168 while ((len -= 16) >= 0) { 169 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3]; 170 lw += 4; 171 } 172 len += 16; 173 while ((len -= 4) >= 0) { 174 sum += (u_int64_t) *lw++; 175 } 176 len += 4; 177 if (len > 0) 178 sum += (u_int64_t) (in_masks[len] & *lw); 179 REDUCE32; 180 return sum; 181 } 182 183 u_short 184 in_addword(u_short a, u_short b) 185 { 186 u_int64_t sum = a + b; 187 188 ADDCARRY(sum); 189 return (sum); 190 } 191 192 u_short 193 in_pseudo(u_int32_t a, u_int32_t b, u_int32_t c) 194 { 195 u_int64_t sum; 196 union q_util q_util; 197 union l_util l_util; 198 199 sum = (u_int64_t) a + b + c; 200 REDUCE16; 201 return (sum); 202 } 203 204 struct cksum_skip_partial_args { 205 uint64_t csum; 206 int clen; 207 }; 208 209 static int 210 in_cksum_skip_partial(void *arg, void *data, u_int len) 211 { 212 struct cksum_skip_partial_args *a; 213 214 a = arg; 215 if (((uintptr_t)data ^ a->clen) & 1) 216 a->csum += in_cksumdata(data, len) << 8; 217 else 218 a->csum += in_cksumdata(data, len); 219 a->clen += len; 220 return (0); 221 } 222 223 u_short 224 in_cksum_skip(struct mbuf *m, int len, int skip) 225 { 226 struct cksum_skip_partial_args a; 227 union q_util q_util; 228 union l_util l_util; 229 uint64_t sum; 230 231 len -= skip; 232 233 /* 234 * The use of m_apply() allows this routine to operate on unmapped 235 * mbufs. 236 */ 237 a.csum = 0; 238 a.clen = 0; 239 (void)m_apply(m, skip, len, in_cksum_skip_partial, &a); 240 sum = a.csum; 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 } 253 254 #endif /* !HAVE_MD_IN_CKSUM */ 255