1 /* $NetBSD: in_cksum.c,v 1.10 2005/12/24 23:24:01 perry Exp $ */ 2 3 /* 4 * Copyright 2001 Wasabi Systems, Inc. 5 * All rights reserved. 6 * 7 * Written by Simon Burge and Eduardo Horvath for Wasabi Systems, Inc. 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 for the NetBSD Project by 20 * Wasabi Systems, Inc. 21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse 22 * or promote products derived from this software without specific prior 23 * written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC 29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35 * POSSIBILITY OF SUCH DAMAGE. 36 */ 37 38 #include <sys/cdefs.h> 39 __KERNEL_RCSID(0, "$NetBSD: in_cksum.c,v 1.10 2005/12/24 23:24:01 perry Exp $"); 40 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 <netinet/ip_var.h> 48 49 /* 50 * Checksum routine for Internet Protocol family headers. 51 * 52 * This routine is very heavily used in the network 53 * code and should be modified for each CPU to be as fast as possible. 54 * 55 * PowerPC version. 56 */ 57 58 #define REDUCE1 sum = (sum & 0xffff) + (sum >> 16) 59 /* Two REDUCE1s is faster than REDUCE1; if (sum > 65535) sum -= 65536; */ 60 #define REDUCE { REDUCE1; REDUCE1; } 61 62 static inline int 63 in_cksum_internal(struct mbuf *m, int off, int len, u_int sum) 64 { 65 uint8_t *w; 66 int mlen = 0; 67 int byte_swapped = 0; 68 int n; 69 70 union { 71 uint8_t c[2]; 72 uint16_t s; 73 } s_util; 74 75 for (;m && len; m = m->m_next) { 76 if (m->m_len == 0) 77 continue; 78 w = mtod(m, uint8_t *) + off; 79 80 /* 81 * 'off' can only be non-zero on the first pass of this 82 * loop when mlen != -1, so we don't need to worry about 83 * 'off' in the if clause below. 84 */ 85 if (mlen == -1) { 86 /* 87 * The first byte of this mbuf is the continuation 88 * of a word spanning between this mbuf and the 89 * last mbuf. 90 * 91 * s_util.c[0] is already saved when scanning previous 92 * mbuf. 93 */ 94 s_util.c[1] = *w++; 95 sum += s_util.s; 96 mlen = m->m_len - 1; 97 len--; 98 } else { 99 mlen = m->m_len - off; 100 off = 0; 101 } 102 if (len < mlen) 103 mlen = len; 104 len -= mlen; 105 106 /* 107 * Force to a word boundary. 108 */ 109 if ((3 & (long) w) && (mlen > 0)) { 110 if ((1 & (long) w)) { 111 REDUCE; 112 sum <<= 8; 113 s_util.c[0] = *w++; 114 mlen--; 115 byte_swapped = 1; 116 } 117 if ((2 & (long) w) && (mlen > 1)) { 118 /* 119 * Since the `sum' may contain full 32 bit 120 * value, we can't simply add any value. 121 */ 122 __asm volatile( 123 "lhz 7,0(%1);" /* load current data 124 half word */ 125 "addc %0,%0,7;" /* add to sum */ 126 "addze %0,%0;" /* add carry bit */ 127 : "+r"(sum) 128 : "b"(w) 129 : "7"); /* clobber r7 */ 130 w += 2; 131 mlen -= 2; 132 } 133 } 134 135 if (mlen >= 64) { 136 n = mlen >> 6; 137 __asm volatile( 138 "addic 0,0,0;" /* clear carry */ 139 "mtctr %1;" /* load loop count */ 140 "1:" 141 "lwz 7,4(%2);" /* load current data 142 word */ 143 "lwz 8,8(%2);" 144 "lwz 9,12(%2);" 145 "lwz 10,16(%2);" 146 "adde %0,%0,7;" /* add to sum */ 147 "adde %0,%0,8;" 148 "adde %0,%0,9;" 149 "adde %0,%0,10;" 150 "lwz 7,20(%2);" 151 "lwz 8,24(%2);" 152 "lwz 9,28(%2);" 153 "lwz 10,32(%2);" 154 "adde %0,%0,7;" 155 "adde %0,%0,8;" 156 "adde %0,%0,9;" 157 "adde %0,%0,10;" 158 "lwz 7,36(%2);" 159 "lwz 8,40(%2);" 160 "lwz 9,44(%2);" 161 "lwz 10,48(%2);" 162 "adde %0,%0,7;" 163 "adde %0,%0,8;" 164 "adde %0,%0,9;" 165 "adde %0,%0,10;" 166 "lwz 7,52(%2);" 167 "lwz 8,56(%2);" 168 "lwz 9,60(%2);" 169 "lwzu 10,64(%2);" 170 "adde %0,%0,7;" 171 "adde %0,%0,8;" 172 "adde %0,%0,9;" 173 "adde %0,%0,10;" 174 "bdnz 1b;" /* loop */ 175 "addze %0,%0;" /* add carry bit */ 176 : "+r"(sum) 177 : "r"(n), "b"(w - 4) 178 : "7", "8", "9", "10"); /* clobber r7, r8, r9, 179 r10 */ 180 w += n * 64; 181 mlen -= n * 64; 182 } 183 184 if (mlen >= 8) { 185 n = mlen >> 3; 186 __asm volatile( 187 "addic 0,0,0;" /* clear carry */ 188 "mtctr %1;" /* load loop count */ 189 "1:" 190 "lwz 7,4(%2);" /* load current data 191 word */ 192 "lwzu 8,8(%2);" 193 "adde %0,%0,7;" /* add to sum */ 194 "adde %0,%0,8;" 195 "bdnz 1b;" /* loop */ 196 "addze %0,%0;" /* add carry bit */ 197 : "+r"(sum) 198 : "r"(n), "b"(w - 4) 199 : "7", "8"); /* clobber r7, r8 */ 200 w += n * 8; 201 mlen -= n * 8; 202 } 203 204 if (mlen == 0 && byte_swapped == 0) 205 continue; 206 REDUCE; 207 208 while ((mlen -= 2) >= 0) { 209 sum += *(uint16_t *)w; 210 w += 2; 211 } 212 213 if (byte_swapped) { 214 REDUCE; 215 sum <<= 8; 216 byte_swapped = 0; 217 if (mlen == -1) { 218 s_util.c[1] = *w; 219 sum += s_util.s; 220 mlen = 0; 221 } else 222 mlen = -1; 223 } else if (mlen == -1) 224 s_util.c[0] = *w; 225 } 226 if (len) 227 printf("cksum: out of data\n"); 228 if (mlen == -1) { 229 /* The last mbuf has odd # of bytes. Follow the 230 standard (the odd byte may be shifted left by 8 bits 231 or not as determined by endian-ness of the machine) */ 232 s_util.c[1] = 0; 233 sum += s_util.s; 234 } 235 REDUCE; 236 return (~sum & 0xffff); 237 } 238 239 int 240 in_cksum(struct mbuf *m, int len) 241 { 242 243 return (in_cksum_internal(m, 0, len, 0)); 244 } 245 246 int 247 in4_cksum(struct mbuf *m, uint8_t nxt, int off, int len) 248 { 249 uint16_t *w; 250 u_int sum = 0; 251 union { 252 struct ipovly ipov; 253 u_int16_t w[10]; 254 } u; 255 256 if (nxt != 0) { 257 /* pseudo header */ 258 memset(&u.ipov, 0, sizeof(u.ipov)); 259 u.ipov.ih_len = htons(len); 260 u.ipov.ih_pr = nxt; 261 u.ipov.ih_src = mtod(m, struct ip *)->ip_src; 262 u.ipov.ih_dst = mtod(m, struct ip *)->ip_dst; 263 w = u.w; 264 /* assumes sizeof(ipov) == 20 */ 265 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; sum += w[4]; 266 sum += w[5]; sum += w[6]; sum += w[7]; sum += w[8]; sum += w[9]; 267 } 268 269 /* skip unnecessary part */ 270 while (m && off > 0) { 271 if (m->m_len > off) 272 break; 273 off -= m->m_len; 274 m = m->m_next; 275 } 276 277 return (in_cksum_internal(m, off, len, sum)); 278 } 279
Indexes created Sun Oct 25 00:26:45 UTC 2026