bsd/netinet/in_cksum.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1988, 1992, 1993
  24  *      The Regents of the University of California.  All rights reserved.
  25  *
  26  * Redistribution and use in source and binary forms, with or without
  27  * modification, are permitted provided that the following conditions
  28  * are met:
  29  * 1. Redistributions of source code must retain the above copyright
  30  *    notice, this list of conditions and the following disclaimer.
  31  * 2. Redistributions in binary form must reproduce the above copyright
  32  *    notice, this list of conditions and the following disclaimer in the
  33  *    documentation and/or other materials provided with the distribution.
  34  * 3. All advertising materials mentioning features or use of this software
  35  *    must display the following acknowledgement:
  36  *      This product includes software developed by the University of
  37  *      California, Berkeley and its contributors.
  38  * 4. Neither the name of the University nor the names of its contributors
  39  *    may be used to endorse or promote products derived from this software
  40  *    without specific prior written permission.
  41  *
  42  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  43  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  44  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  45  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  46  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  47  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  48  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  49  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  50  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  51  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  52  * SUCH DAMAGE.
  53  *
  54  *      @(#)in_cksum.c  8.1 (Berkeley) 6/10/93
  55  */
  56
  57 #include <sys/param.h>
  58 #include <sys/mbuf.h>
  59 #include <sys/kdebug.h>
  60
  61 #define DBG_FNC_IN_CKSUM        NETDBG_CODE(DBG_NETIP, (3 << 8))
  62
  63 /*
  64  * Checksum routine for Internet Protocol family headers (Portable Version).
  65  *
  66  * This routine is very heavily used in the network
  67  * code and should be modified for each CPU to be as fast as possible.
  68  */
  69
  70 union s_util {
  71         char    c[2];
  72         u_short s;
  73 };
  74
  75 union l_util {
  76         u_int16_t s[2];
  77         u_int32_t l;
  78 };
  79
  80 union q_util {
  81         u_int16_t s[4];
  82         u_int32_t l[2];
  83         u_int64_t q;
  84 };
  85
  86 #define ADDCARRY(x)  (x > 65535 ? x -= 65535 : x)
  87
  88 #define REDUCE32                                                          \
  89     {                                                                     \
  90         q_util.q = sum;                                                   \
  91         sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3];      \
  92     }
  93 #define REDUCE16                                                          \
  94     {                                                                     \
  95         q_util.q = sum;                                                   \
  96         l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
  97         sum = l_util.s[0] + l_util.s[1];                                  \
  98         ADDCARRY(sum);                                                    \
  99     }
 100
 101 #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);}
 102
 103
 104 #if defined(ppc)
 105
 106 __inline unsigned short
 107 in_addword(u_short a, u_short b)
 108 {
 109         union l_util l_util;
 110         u_int32_t sum = a + b;
 111         REDUCE;
 112         return (sum);
 113 }
 114
 115 __inline unsigned short
 116 in_pseudo(u_int a, u_int b, u_int c)
 117 {
 118         u_int64_t sum;
 119         union q_util q_util;
 120         union l_util l_util;
 121
 122         sum = (u_int64_t) a + b + c;
 123         REDUCE16;
 124         return (sum);
 125
 126 }
 127
 128 int
 129 in_cksum(m, len)
 130         register struct mbuf *m;
 131         register int len;
 132 {
 133         register u_short *w;
 134         register int sum = 0;
 135         register int mlen = 0;
 136         int starting_on_odd  = 0;
 137
 138
 139         KERNEL_DEBUG(DBG_FNC_IN_CKSUM | DBG_FUNC_START, len,0,0,0,0);
 140
 141         for (;m && len; m = m->m_next) {
 142                 if (m->m_len == 0)
 143                         continue;
 144                 mlen = m->m_len;
 145                 w = mtod(m, u_short *);
 146
 147                 if (len < mlen)
 148                         mlen = len;
 149
 150                 sum = xsum_assym(w, mlen, sum, starting_on_odd);
 151                 len -= mlen;
 152                 if (mlen & 0x1)
 153                 {
 154                     if (starting_on_odd)
 155                         starting_on_odd = 0;
 156                     else
 157                         starting_on_odd = 1;
 158                 }
 159         }
 160
 161         KERNEL_DEBUG(DBG_FNC_IN_CKSUM | DBG_FUNC_END, 0,0,0,0,0);
 162         return (~sum & 0xffff);
 163 }
 164
 165 u_short
 166 in_cksum_skip(m, len, skip)
 167         register struct mbuf *m;
 168         register int len;
 169         register int skip;
 170 {
 171         register u_short *w;
 172         register int sum = 0;
 173         register int mlen = 0;
 174         int starting_on_odd  = 0;
 175
 176         len -= skip;
 177         for (; skip && m; m = m->m_next) {
 178                 if (m->m_len > skip) {
 179                         mlen = m->m_len - skip;
 180                         w = (u_short *)(m->m_data+skip);
 181                         goto skip_start;
 182                 } else {
 183                         skip -= m->m_len;
 184                 }
 185         }
 186         for (;m && len; m = m->m_next) {
 187                 if (m->m_len == 0)
 188                         continue;
 189                 mlen = m->m_len;
 190                 w = mtod(m, u_short *);
 191
 192                 if (len < mlen)
 193                         mlen = len;
 194 skip_start:
 195                 sum = xsum_assym(w, mlen, sum, starting_on_odd);
 196                 len -= mlen;
 197                 if (mlen & 0x1)
 198                 {
 199                     if (starting_on_odd)
 200                         starting_on_odd = 0;
 201                     else
 202                         starting_on_odd = 1;
 203                 }
 204         }
 205
 206         return (~sum & 0xffff);
 207 }
 208 #else
 209
 210 u_short
 211 in_addword(u_short a, u_short b)
 212 {
 213         union l_util l_util;
 214         u_int32_t sum = a + b;
 215         REDUCE(sum);
 216         return (sum);
 217 }
 218
 219 u_short
 220 in_pseudo(u_int a, u_int b, u_int c)
 221 {
 222         u_int64_t sum;
 223         union q_util q_util;
 224         union l_util l_util;
 225
 226         sum = (u_int64_t) a + b + c;
 227         REDUCE16;
 228         return (sum);
 229 }
 230
 231
 232 int
 233 in_cksum(m, len)
 234         register struct mbuf *m;
 235         register int len;
 236 {
 237         register u_short *w;
 238         register int sum = 0;
 239         register int mlen = 0;
 240         int byte_swapped = 0;
 241         union s_util s_util;
 242         union l_util l_util;
 243
 244         KERNEL_DEBUG(DBG_FNC_IN_CKSUM | DBG_FUNC_START, len,0,0,0,0);
 245
 246         for (;m && len; m = m->m_next) {
 247                 if (m->m_len == 0)
 248                         continue;
 249                 w = mtod(m, u_short *);
 250                 if (mlen == -1) {
 251                         /*
 252                          * The first byte of this mbuf is the continuation
 253                          * of a word spanning between this mbuf and the
 254                          * last mbuf.
 255                          *
 256                          * s_util.c[0] is already saved when scanning previous
 257                          * mbuf.
 258                          */
 259                         s_util.c[1] = *(char *)w;
 260                         sum += s_util.s;
 261                         w = (u_short *)((char *)w + 1);
 262                         mlen = m->m_len - 1;
 263                         len--;
 264                 } else
 265                         mlen = m->m_len;
 266                 if (len < mlen)
 267                         mlen = len;
 268                 len -= mlen;
 269                 /*
 270                  * Force to even boundary.
 271                  */
 272                 if ((1 & (int) w) && (mlen > 0)) {
 273                         REDUCE;
 274                         sum <<= 8;
 275                         s_util.c[0] = *(u_char *)w;
 276                         w = (u_short *)((char *)w + 1);
 277                         mlen--;
 278                         byte_swapped = 1;
 279                 }
 280                 /*
 281                  * Unroll the loop to make overhead from
 282                  * branches &c small.
 283                  */
 284                 while ((mlen -= 32) >= 0) {
 285                         sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
 286                         sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
 287                         sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
 288                         sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
 289                         w += 16;
 290                 }
 291                 mlen += 32;
 292                 while ((mlen -= 8) >= 0) {
 293                         sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
 294                         w += 4;
 295                 }
 296                 mlen += 8;
 297                 if (mlen == 0 && byte_swapped == 0)
 298                         continue;
 299                 REDUCE;
 300                 while ((mlen -= 2) >= 0) {
 301                         sum += *w++;
 302                 }
 303                 if (byte_swapped) {
 304                         REDUCE;
 305                         sum <<= 8;
 306                         byte_swapped = 0;
 307                         if (mlen == -1) {
 308                                 s_util.c[1] = *(char *)w;
 309                                 sum += s_util.s;
 310                                 mlen = 0;
 311                         } else
 312                                 mlen = -1;
 313                 } else if (mlen == -1)
 314                         s_util.c[0] = *(char *)w;
 315         }
 316         if (len)
 317                 printf("cksum: out of data\n");
 318         if (mlen == -1) {
 319                 /* The last mbuf has odd # of bytes. Follow the
 320                    standard (the odd byte may be shifted left by 8 bits
 321                    or not as determined by endian-ness of the machine) */
 322                 s_util.c[1] = 0;
 323                 sum += s_util.s;
 324         }
 325         REDUCE;
 326         KERNEL_DEBUG(DBG_FNC_IN_CKSUM | DBG_FUNC_END, 0,0,0,0,0);
 327         return (~sum & 0xffff);
 328 }
 329
 330 int
 331 in_cksum_skip(m, len, skip)
 332         register struct mbuf *m;
 333         register u_short len;
 334         register u_short skip;
 335 {
 336         register u_short *w;
 337         register int sum = 0;
 338         register int mlen = 0;
 339         int byte_swapped = 0;
 340         union s_util s_util;
 341         union l_util l_util;
 342
 343         KERNEL_DEBUG(DBG_FNC_IN_CKSUM | DBG_FUNC_START, len,0,0,0,0);
 344
 345         len -= skip;
 346         for (; skip && m; m = m->m_next) {
 347                 if (m->m_len > skip) {
 348                         mlen = m->m_len - skip;
 349                         w = (u_short *)(m->m_data+skip);
 350                         goto skip_start;
 351                 } else {
 352                         skip -= m->m_len;
 353                 }
 354         }
 355         for (;m && len; m = m->m_next) {
 356                 if (m->m_len == 0)
 357                         continue;
 358                 w = mtod(m, u_short *);
 359
 360                 if (mlen == -1) {
 361                         /*
 362                          * The first byte of this mbuf is the continuation
 363                          * of a word spanning between this mbuf and the
 364                          * last mbuf.
 365                          *
 366                          * s_util.c[0] is already saved when scanning previous
 367                          * mbuf.
 368                          */
 369                         s_util.c[1] = *(char *)w;
 370                         sum += s_util.s;
 371                         w = (u_short *)((char *)w + 1);
 372                         mlen = m->m_len - 1;
 373                         len--;
 374                 } else {
 375                   mlen = m->m_len;
 376                 }
 377                   if (len < mlen)
 378                     mlen = len;
 379 skip_start:
 380
 381                 len -= mlen;
 382                 /*
 383                  * Force to even boundary.
 384                  */
 385                 if ((1 & (int) w) && (mlen > 0)) {
 386                         REDUCE;
 387                         sum <<= 8;
 388                         s_util.c[0] = *(u_char *)w;
 389                         w = (u_short *)((char *)w + 1);
 390                         mlen--;
 391                         byte_swapped = 1;
 392                 }
 393                 /*
 394                  * Unroll the loop to make overhead from
 395                  * branches &c small.
 396                  */
 397                 while ((mlen -= 32) >= 0) {
 398                         sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
 399                         sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
 400                         sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
 401                         sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
 402                         w += 16;
 403                 }
 404                 mlen += 32;
 405                 while ((mlen -= 8) >= 0) {
 406                         sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
 407                         w += 4;
 408                 }
 409                 mlen += 8;
 410                 if (mlen == 0 && byte_swapped == 0)
 411                         continue;
 412                 REDUCE;
 413                 while ((mlen -= 2) >= 0) {
 414                         sum += *w++;
 415                 }
 416                 if (byte_swapped) {
 417                         REDUCE;
 418                         sum <<= 8;
 419                         byte_swapped = 0;
 420                         if (mlen == -1) {
 421                                 s_util.c[1] = *(char *)w;
 422                                 sum += s_util.s;
 423                                 mlen = 0;
 424                         } else
 425                                 mlen = -1;
 426                 } else if (mlen == -1)
 427                         s_util.c[0] = *(char *)w;
 428         }
 429         if (len)
 430                 printf("cksum: out of data\n");
 431         if (mlen == -1) {
 432                 /* The last mbuf has odd # of bytes. Follow the
 433                    standard (the odd byte may be shifted left by 8 bits
 434                    or not as determined by endian-ness of the machine) */
 435                 s_util.c[1] = 0;
 436                 sum += s_util.s;
 437         }
 438         REDUCE;
 439         KERNEL_DEBUG(DBG_FNC_IN_CKSUM | DBG_FUNC_END, 0,0,0,0,0);
 440         return (~sum & 0xffff);
 441 }
 442
 443 #endif