bsd/netinet/in_cksum.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * Copyright (c) 1988, 1992, 1993
  30  *      The Regents of the University of California.  All rights reserved.
  31  *
  32  * Redistribution and use in source and binary forms, with or without
  33  * modification, are permitted provided that the following conditions
  34  * are met:
  35  * 1. Redistributions of source code must retain the above copyright
  36  *    notice, this list of conditions and the following disclaimer.
  37  * 2. Redistributions in binary form must reproduce the above copyright
  38  *    notice, this list of conditions and the following disclaimer in the
  39  *    documentation and/or other materials provided with the distribution.
  40  * 3. All advertising materials mentioning features or use of this software
  41  *    must display the following acknowledgement:
  42  *      This product includes software developed by the University of
  43  *      California, Berkeley and its contributors.
  44  * 4. Neither the name of the University nor the names of its contributors
  45  *    may be used to endorse or promote products derived from this software
  46  *    without specific prior written permission.
  47  *
  48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  58  * SUCH DAMAGE.
  59  *
  60  *      @(#)in_cksum.c  8.1 (Berkeley) 6/10/93
  61  */
  62
  63 #include <sys/param.h>
  64 #include <sys/mbuf.h>
  65 #include <sys/kdebug.h>
  66
  67 #define DBG_FNC_IN_CKSUM        NETDBG_CODE(DBG_NETIP, (3 << 8))
  68
  69 /*
  70  * Checksum routine for Internet Protocol family headers (Portable Version).
  71  *
  72  * This routine is very heavily used in the network
  73  * code and should be modified for each CPU to be as fast as possible.
  74  */
  75
  76 union s_util {
  77         char    c[2];
  78         u_short s;
  79 };
  80
  81 union l_util {
  82         u_int16_t s[2];
  83         u_int32_t l;
  84 };
  85
  86 union q_util {
  87         u_int16_t s[4];
  88         u_int32_t l[2];
  89         u_int64_t q;
  90 };
  91
  92 #define ADDCARRY(x)  (x > 65535 ? x -= 65535 : x)
  93
  94 #define REDUCE32                                                          \
  95     {                                                                     \
  96         q_util.q = sum;                                                   \
  97         sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3];      \
  98     }
  99 #define REDUCE16                                                          \
 100     {                                                                     \
 101         q_util.q = sum;                                                   \
 102         l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
 103         sum = l_util.s[0] + l_util.s[1];                                  \
 104         ADDCARRY(sum);                                                    \
 105     }
 106
 107 #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);}
 108
 109
 110 #if defined(ppc)
 111
 112 __inline unsigned short
 113 in_addword(u_short a, u_short b)
 114 {
 115         union l_util l_util;
 116         u_int32_t sum = a + b;
 117         REDUCE;
 118         return (sum);
 119 }
 120
 121 __inline unsigned short
 122 in_pseudo(u_int a, u_int b, u_int c)
 123 {
 124         u_int64_t sum;
 125         union q_util q_util;
 126         union l_util l_util;
 127
 128         sum = (u_int64_t) a + b + c;
 129         REDUCE16;
 130         return (sum);
 131
 132 }
 133
 134 int
 135 in_cksum(m, len)
 136         register struct mbuf *m;
 137         register int len;
 138 {
 139         register u_short *w;
 140         register int sum = 0;
 141         register int mlen = 0;
 142         int starting_on_odd  = 0;
 143
 144
 145         KERNEL_DEBUG(DBG_FNC_IN_CKSUM | DBG_FUNC_START, len,0,0,0,0);
 146
 147         for (;m && len; m = m->m_next) {
 148                 if (m->m_len == 0)
 149                         continue;
 150                 mlen = m->m_len;
 151                 w = mtod(m, u_short *);
 152
 153                 if (len < mlen)
 154                         mlen = len;
 155
 156                 sum = xsum_assym(w, mlen, sum, starting_on_odd);
 157                 len -= mlen;
 158                 if (mlen & 0x1)
 159                 {
 160                     if (starting_on_odd)
 161                         starting_on_odd = 0;
 162                     else
 163                         starting_on_odd = 1;
 164                 }
 165         }
 166
 167         KERNEL_DEBUG(DBG_FNC_IN_CKSUM | DBG_FUNC_END, 0,0,0,0,0);
 168         return (~sum & 0xffff);
 169 }
 170
 171 u_short
 172 in_cksum_skip(m, len, skip)
 173         register struct mbuf *m;
 174         register int len;
 175         register int skip;
 176 {
 177         register u_short *w;
 178         register int sum = 0;
 179         register int mlen = 0;
 180         int starting_on_odd  = 0;
 181
 182         len -= skip;
 183         for (; skip && m; m = m->m_next) {
 184                 if (m->m_len > skip) {
 185                         mlen = m->m_len - skip;
 186                         w = (u_short *)(m->m_data+skip);
 187                         goto skip_start;
 188                 } else {
 189                         skip -= m->m_len;
 190                 }
 191         }
 192         for (;m && len; m = m->m_next) {
 193                 if (m->m_len == 0)
 194                         continue;
 195                 mlen = m->m_len;
 196                 w = mtod(m, u_short *);
 197
 198 skip_start:
 199                 if (len < mlen)
 200                         mlen = len;
 201                 sum = xsum_assym(w, mlen, sum, starting_on_odd);
 202                 len -= mlen;
 203                 if (mlen & 0x1)
 204                 {
 205                     if (starting_on_odd)
 206                         starting_on_odd = 0;
 207                     else
 208                         starting_on_odd = 1;
 209                 }
 210         }
 211
 212         return (~sum & 0xffff);
 213 }
 214 #else
 215
 216 u_short
 217 in_addword(u_short a, u_short b)
 218 {
 219         union l_util l_util;
 220         u_int32_t sum = a + b;
 221         REDUCE(sum);
 222         return (sum);
 223 }
 224
 225 u_short
 226 in_pseudo(u_int a, u_int b, u_int c)
 227 {
 228         u_int64_t sum;
 229         union q_util q_util;
 230         union l_util l_util;
 231
 232         sum = (u_int64_t) a + b + c;
 233         REDUCE16;
 234         return (sum);
 235 }
 236
 237
 238 int
 239 in_cksum(m, len)
 240         register struct mbuf *m;
 241         register int len;
 242 {
 243         register u_short *w;
 244         register int sum = 0;
 245         register int mlen = 0;
 246         int byte_swapped = 0;
 247         union s_util s_util;
 248         union l_util l_util;
 249
 250         KERNEL_DEBUG(DBG_FNC_IN_CKSUM | DBG_FUNC_START, len,0,0,0,0);
 251
 252         for (;m && len; m = m->m_next) {
 253                 if (m->m_len == 0)
 254                         continue;
 255                 w = mtod(m, u_short *);
 256                 if (mlen == -1) {
 257                         /*
 258                          * The first byte of this mbuf is the continuation
 259                          * of a word spanning between this mbuf and the
 260                          * last mbuf.
 261                          *
 262                          * s_util.c[0] is already saved when scanning previous
 263                          * mbuf.
 264                          */
 265                         s_util.c[1] = *(char *)w;
 266                         sum += s_util.s;
 267                         w = (u_short *)((char *)w + 1);
 268                         mlen = m->m_len - 1;
 269                         len--;
 270                 } else
 271                         mlen = m->m_len;
 272                 if (len < mlen)
 273                         mlen = len;
 274                 len -= mlen;
 275                 /*
 276                  * Force to even boundary.
 277                  */
 278                 if ((1 & (int) w) && (mlen > 0)) {
 279                         REDUCE;
 280                         sum <<= 8;
 281                         s_util.c[0] = *(u_char *)w;
 282                         w = (u_short *)((char *)w + 1);
 283                         mlen--;
 284                         byte_swapped = 1;
 285                 }
 286                 /*
 287                  * Unroll the loop to make overhead from
 288                  * branches &c small.
 289                  */
 290                 while ((mlen -= 32) >= 0) {
 291                         sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
 292                         sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
 293                         sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
 294                         sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
 295                         w += 16;
 296                 }
 297                 mlen += 32;
 298                 while ((mlen -= 8) >= 0) {
 299                         sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
 300                         w += 4;
 301                 }
 302                 mlen += 8;
 303                 if (mlen == 0 && byte_swapped == 0)
 304                         continue;
 305                 REDUCE;
 306                 while ((mlen -= 2) >= 0) {
 307                         sum += *w++;
 308                 }
 309                 if (byte_swapped) {
 310                         REDUCE;
 311                         sum <<= 8;
 312                         byte_swapped = 0;
 313                         if (mlen == -1) {
 314                                 s_util.c[1] = *(char *)w;
 315                                 sum += s_util.s;
 316                                 mlen = 0;
 317                         } else
 318                                 mlen = -1;
 319                 } else if (mlen == -1)
 320                         s_util.c[0] = *(char *)w;
 321         }
 322         if (len)
 323                 printf("cksum: out of data\n");
 324         if (mlen == -1) {
 325                 /* The last mbuf has odd # of bytes. Follow the
 326                    standard (the odd byte may be shifted left by 8 bits
 327                    or not as determined by endian-ness of the machine) */
 328                 s_util.c[1] = 0;
 329                 sum += s_util.s;
 330         }
 331         REDUCE;
 332         KERNEL_DEBUG(DBG_FNC_IN_CKSUM | DBG_FUNC_END, 0,0,0,0,0);
 333         return (~sum & 0xffff);
 334 }
 335
 336 int
 337 in_cksum_skip(m, len, skip)
 338         register struct mbuf *m;
 339         register u_short len;
 340         register u_short skip;
 341 {
 342         register u_short *w;
 343         register int sum = 0;
 344         register int mlen = 0;
 345         int byte_swapped = 0;
 346         union s_util s_util;
 347         union l_util l_util;
 348
 349         KERNEL_DEBUG(DBG_FNC_IN_CKSUM | DBG_FUNC_START, len,0,0,0,0);
 350
 351         len -= skip;
 352         for (; skip && m; m = m->m_next) {
 353                 if (m->m_len > skip) {
 354                         mlen = m->m_len - skip;
 355                         w = (u_short *)(m->m_data+skip);
 356                         goto skip_start;
 357                 } else {
 358                         skip -= m->m_len;
 359                 }
 360         }
 361         for (;m && len; m = m->m_next) {
 362                 if (m->m_len == 0)
 363                         continue;
 364                 w = mtod(m, u_short *);
 365
 366                 if (mlen == -1) {
 367                         /*
 368                          * The first byte of this mbuf is the continuation
 369                          * of a word spanning between this mbuf and the
 370                          * last mbuf.
 371                          *
 372                          * s_util.c[0] is already saved when scanning previous
 373                          * mbuf.
 374                          */
 375                         s_util.c[1] = *(char *)w;
 376                         sum += s_util.s;
 377                         w = (u_short *)((char *)w + 1);
 378                         mlen = m->m_len - 1;
 379                         len--;
 380                 } else {
 381                   mlen = m->m_len;
 382                 }
 383 skip_start:
 384                 if (len < mlen)
 385                     mlen = len;
 386
 387                 len -= mlen;
 388                 /*
 389                  * Force to even boundary.
 390                  */
 391                 if ((1 & (int) w) && (mlen > 0)) {
 392                         REDUCE;
 393                         sum <<= 8;
 394                         s_util.c[0] = *(u_char *)w;
 395                         w = (u_short *)((char *)w + 1);
 396                         mlen--;
 397                         byte_swapped = 1;
 398                 }
 399                 /*
 400                  * Unroll the loop to make overhead from
 401                  * branches &c small.
 402                  */
 403                 while ((mlen -= 32) >= 0) {
 404                         sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
 405                         sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
 406                         sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
 407                         sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
 408                         w += 16;
 409                 }
 410                 mlen += 32;
 411                 while ((mlen -= 8) >= 0) {
 412                         sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
 413                         w += 4;
 414                 }
 415                 mlen += 8;
 416                 if (mlen == 0 && byte_swapped == 0)
 417                         continue;
 418                 REDUCE;
 419                 while ((mlen -= 2) >= 0) {
 420                         sum += *w++;
 421                 }
 422                 if (byte_swapped) {
 423                         REDUCE;
 424                         sum <<= 8;
 425                         byte_swapped = 0;
 426                         if (mlen == -1) {
 427                                 s_util.c[1] = *(char *)w;
 428                                 sum += s_util.s;
 429                                 mlen = 0;
 430                         } else
 431                                 mlen = -1;
 432                 } else if (mlen == -1)
 433                         s_util.c[0] = *(char *)w;
 434         }
 435         if (len)
 436                 printf("cksum: out of data\n");
 437         if (mlen == -1) {
 438                 /* The last mbuf has odd # of bytes. Follow the
 439                    standard (the odd byte may be shifted left by 8 bits
 440                    or not as determined by endian-ness of the machine) */
 441                 s_util.c[1] = 0;
 442                 sum += s_util.s;
 443         }
 444         REDUCE;
 445         KERNEL_DEBUG(DBG_FNC_IN_CKSUM | DBG_FUNC_END, 0,0,0,0,0);
 446         return (~sum & 0xffff);
 447 }
 448
 449 #endif