1/* $OpenBSD: in_cksum.c,v 1.11 2022/02/01 15:30:10 miod Exp $ */ 2/* $NetBSD: in_cksum.c,v 1.7 2003/07/15 02:54:48 lukem Exp $ */ 3 4/* 5 * Copyright 2001 Wasabi Systems, Inc. 6 * All rights reserved. 7 * 8 * Written by Simon Burge and Eduardo Horvath for Wasabi Systems, Inc. 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 for the NetBSD Project by 21 * Wasabi Systems, Inc. 22 * 4. The name of Wasabi Systems, Inc. may not be used to endorse 23 * or promote products derived from this software without specific prior 24 * written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39#include <sys/param.h> 40#include <sys/systm.h> 41#include <sys/mbuf.h> 42#include <sys/socketvar.h> 43 44#include <netinet/in.h> 45#include <netinet/ip.h> 46#include <netinet/ip_var.h> 47 48/* 49 * Checksum routine for Internet Protocol family headers. 50 * 51 * This routine is very heavily used in the network 52 * code and should be modified for each CPU to be as fast as possible. 53 * 54 * PowerPC version. 55 */ 56 57#define REDUCE1 sum = (sum & 0xffff) + (sum >> 16) 58/* Two REDUCE1s is faster than REDUCE1; if (sum > 65535) sum -= 65536; */ 59#define REDUCE { REDUCE1; REDUCE1; } 60 61static __inline__ int 62in_cksum_internal(struct mbuf *m, int off, int len, u_int sum) 63{ 64 uint8_t *w; 65 int mlen = 0; 66 int byte_swapped = 0; 67 int n; 68 69 union { 70 uint8_t c[2]; 71 uint16_t s; 72 } s_util; 73 74 for (;m && len; m = m->m_next) { 75 if (m->m_len == 0) 76 continue; 77 w = mtod(m, uint8_t *) + off; 78 79 /* 80 * 'off' can only be non-zero on the first pass of this 81 * loop when mlen != -1, so we don't need to worry about 82 * 'off' in the if clause below. 83 */ 84 if (mlen == -1) { 85 /* 86 * The first byte of this mbuf is the continuation 87 * of a word spanning between this mbuf and the 88 * last mbuf. 89 * 90 * s_util.c[0] is already saved when scanning previous 91 * mbuf. 92 */ 93 s_util.c[1] = *w++; 94 sum += s_util.s; 95 mlen = m->m_len - 1; 96 len--; 97 } else { 98 mlen = m->m_len - off; 99 off = 0; 100 } 101 if (len < mlen) 102 mlen = len; 103 len -= mlen; 104 105 /* 106 * Force to a word boundary. 107 */ 108 if ((3 & (long) w) && (mlen > 0)) { 109 if ((1 & (long) w)) { 110 REDUCE; 111 sum <<= 8; 112 s_util.c[0] = *w++; 113 mlen--; 114 byte_swapped = 1; 115 } 116 if ((2 & (long) w) && (mlen > 1)) { 117 /* 118 * Since the `sum' may contain full 32 bit 119 * value, we can't simply add any value. 120 */ 121 __asm volatile( 122 "lhz 7,0(%1);" /* load current data 123 half word */ 124 "addc %0,%0,7;" /* add to sum */ 125 "addze %0,%0;" /* add carry bit */ 126 : "+r"(sum) 127 : "b"(w) 128 : "7"); /* clobber r7 */ 129 w += 2; 130 mlen -= 2; 131 } 132 } 133 134 if (mlen >= 64) { 135 n = mlen >> 6; 136 __asm volatile( 137 "addic 0,0,0;" /* clear carry */ 138 "mtctr %1;" /* load loop count */ 139 "1:" 140 "lwz 7,4(%2);" /* load current data 141 word */ 142 "lwz 8,8(%2);" 143 "lwz 9,12(%2);" 144 "lwz 10,16(%2);" 145 "adde %0,%0,7;" /* add to sum */ 146 "adde %0,%0,8;" 147 "adde %0,%0,9;" 148 "adde %0,%0,10;" 149 "lwz 7,20(%2);" 150 "lwz 8,24(%2);" 151 "lwz 9,28(%2);" 152 "lwz 10,32(%2);" 153 "adde %0,%0,7;" 154 "adde %0,%0,8;" 155 "adde %0,%0,9;" 156 "adde %0,%0,10;" 157 "lwz 7,36(%2);" 158 "lwz 8,40(%2);" 159 "lwz 9,44(%2);" 160 "lwz 10,48(%2);" 161 "adde %0,%0,7;" 162 "adde %0,%0,8;" 163 "adde %0,%0,9;" 164 "adde %0,%0,10;" 165 "lwz 7,52(%2);" 166 "lwz 8,56(%2);" 167 "lwz 9,60(%2);" 168 "lwzu 10,64(%2);" 169 "adde %0,%0,7;" 170 "adde %0,%0,8;" 171 "adde %0,%0,9;" 172 "adde %0,%0,10;" 173 "bdnz 1b;" /* loop */ 174 "addze %0,%0;" /* add carry bit */ 175 : "+r"(sum) 176 : "r"(n), "b"(w - 4) 177 : "7", "8", "9", "10"); /* clobber r7, r8, r9, 178 r10 */ 179 w += n * 64; 180 mlen -= n * 64; 181 } 182 183 if (mlen >= 8) { 184 n = mlen >> 3; 185 __asm volatile( 186 "addic 0,0,0;" /* clear carry */ 187 "mtctr %1;" /* load loop count */ 188 "1:" 189 "lwz 7,4(%2);" /* load current data 190 word */ 191 "lwzu 8,8(%2);" 192 "adde %0,%0,7;" /* add to sum */ 193 "adde %0,%0,8;" 194 "bdnz 1b;" /* loop */ 195 "addze %0,%0;" /* add carry bit */ 196 : "+r"(sum) 197 : "r"(n), "b"(w - 4) 198 : "7", "8"); /* clobber r7, r8 */ 199 w += n * 8; 200 mlen -= n * 8; 201 } 202 203 if (mlen == 0 && byte_swapped == 0) 204 continue; 205 REDUCE; 206 207 while ((mlen -= 2) >= 0) { 208 sum += *(uint16_t *)w; 209 w += 2; 210 } 211 212 if (byte_swapped) { 213 REDUCE; 214 sum <<= 8; 215 byte_swapped = 0; 216 if (mlen == -1) { 217 s_util.c[1] = *w; 218 sum += s_util.s; 219 mlen = 0; 220 } else 221 mlen = -1; 222 } else if (mlen == -1) 223 s_util.c[0] = *w; 224 } 225 if (len) 226 printf("cksum: out of data\n"); 227 if (mlen == -1) { 228 /* The last mbuf has odd # of bytes. Follow the 229 standard (the odd byte may be shifted left by 8 bits 230 or not as determined by endian-ness of the machine) */ 231 s_util.c[1] = 0; 232 sum += s_util.s; 233 } 234 REDUCE; 235 return (~sum & 0xffff); 236} 237 238int 239in_cksum(struct mbuf *m, int len) 240{ 241 242 return (in_cksum_internal(m, 0, len, 0)); 243} 244 245int 246in4_cksum(struct mbuf *m, uint8_t nxt, int off, int len) 247{ 248 uint16_t *w; 249 u_int sum = 0; 250 union { 251 struct ipovly ipov; 252 u_int16_t w[10]; 253 } u; 254 255 if (nxt != 0) { 256 /* pseudo header */ 257 u.ipov.ih_x1[8] = 0; 258 u.ipov.ih_pr = nxt; 259 u.ipov.ih_len = htons(len); 260 u.ipov.ih_src = mtod(m, struct ip *)->ip_src; 261 u.ipov.ih_dst = mtod(m, struct ip *)->ip_dst; 262 w = u.w; 263 /* assumes sizeof(ipov) == 20 and first 8 bytes are zeroes */ 264 sum += w[4]; sum += w[5]; sum += w[6]; 265 sum += w[7]; sum += w[8]; sum += w[9]; 266 } 267 268 /* skip unnecessary part */ 269 while (m && off > 0) { 270 if (m->m_len > off) 271 break; 272 off -= m->m_len; 273 m = m->m_next; 274 } 275 276 return (in_cksum_internal(m, off, len, sum)); 277} 278