in_cksum.c

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    1 /*-
    2  * Copyright (c) 1990 The Regents of the University of California.
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  * 4. Neither the name of the University nor the names of its contributors
   14  *    may be used to endorse or promote products derived from this software
   15  *    without specific prior written permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  */
   29 /*-
   30  * Copyright (c) 2001 by Thomas Moestl <tmm@FreeBSD.org>.
   31  * All rights reserved.
   32  *
   33  * Redistribution and use in source and binary forms, with or without
   34  * modification, are permitted provided that the following conditions
   35  * are met:
   36  * 1. Redistributions of source code must retain the above copyright
   37  *    notice, this list of conditions and the following disclaimer.
   38  * 2. Redistributions in binary form must reproduce the above copyright
   39  *    notice, this list of conditions and the following disclaimer in the
   40  *    documentation and/or other materials provided with the distribution.
   41  *
   42  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   43  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   44  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   45  * IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
   46  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   47  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   48  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   49  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   50  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
   51  * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   52  *
   53  *      from tahoe:     in_cksum.c      1.2     86/01/05
   54  *      from:           @(#)in_cksum.c  1.3 (Berkeley) 1/19/91
   55  *      from: FreeBSD: src/sys/i386/i386/in_cksum.c,v 1.22 2000/11/25
   56  *
   57  * $FreeBSD: releng/6.0/sys/sparc64/sparc64/in_cksum.c 127977 2004-04-07 05:00:01Z imp $
   58  */
   59 
   60 #include <sys/param.h>
   61 #include <sys/systm.h>
   62 #include <sys/mbuf.h>
   63 
   64 #include <netinet/in.h>
   65 #include <netinet/in_systm.h>
   66 #include <netinet/ip.h>
   67 
   68 #include <machine/in_cksum.h>
   69 
   70 /*
   71  * Checksum routine for Internet Protocol family headers.
   72  *
   73  * This routine is very heavily used in the network
   74  * code and should be modified for each CPU to be as fast as possible.
   75  *
   76  * This implementation is a sparc64 version. Most code was taken over and
   77  * adapted from the i386. Some optimizations were changed to achieve (hopefully)
   78  * better performance.
   79  * This uses 64 bit loads, but 32 bit additions due to the lack of a 64-bit
   80  * add-with-carry operation.
   81  */
   82 
   83 /*
   84  * REDUCE() is actually not used that frequently... maybe a C implementation
   85  * would suffice.
   86  */
   87 #define REDUCE(sum, tmp) __asm __volatile( \
   88         "sll %2, 16, %1\n" \
   89         "addcc %2, %1, %0\n" \
   90         "srl %0, 16, %0\n" \
   91         "addc %0, 0, %0" : "=r" (sum), "=r" (tmp) : "" (sum))
   92 
   93 /*
   94  * Note that some of these macros depend on the flags being preserved between
   95  * calls, so they should not be intermixed with other C statements.
   96  */
   97 #define LD64_ADD32(sum, tmp, addr, n, mod) __asm __volatile( \
   98         "ldx [%3 + " #n "], %1\n" \
   99         "add" #mod " %2, %1, %0\n" \
  100         "srlx %1, 32, %1\n" \
  101         "addccc %0, %1, %0" : "=r" (sum), "=r" (tmp) : "" (sum), "r" (addr))
  102 
  103 #define LD32_ADD32(sum, tmp, addr, n, mod) __asm __volatile( \
  104         "lduw [%3 + " #n "], %1\n" \
  105         "add" #mod " %2, %1, %0\n" \
  106         : "=r" (sum), "=r" (tmp) : "" (sum), "r" (addr))
  107 
  108 #define MOP(sum) __asm __volatile( \
  109         "addc %1, 0, %0" : "=r" (sum) : "" (sum))
  110 
  111 u_short
  112 in_cksum_skip(struct mbuf *m, int len, int skip)
  113 {
  114         u_short *w;
  115         unsigned long tmp, sum = 0;
  116         int mlen = 0;
  117         int byte_swapped = 0;
  118         u_short su = 0;
  119 
  120         len -= skip;
  121         for (; skip > 0 && m != NULL; m = m->m_next) {
  122                 if (m->m_len > skip) {
  123                         mlen = m->m_len - skip;
  124                         w = (u_short *)(mtod(m, u_char *) + skip);
  125                         goto skip_start;
  126                 } else
  127                         skip -= m->m_len;
  128         }
  129 
  130         for (; m != NULL && len > 0; m = m->m_next) {
  131                 if (m->m_len == 0)
  132                         continue;
  133                 w = mtod(m, u_short *);
  134                 if (mlen == -1) {
  135                         /*
  136                          * The first byte of this mbuf is the continuation
  137                          * of a word spanning between this mbuf and the
  138                          * last mbuf.
  139                          *
  140                          * The high order byte of su is already saved when
  141                          * scanning previous mbuf.  sum was REDUCEd when we
  142                          * found mlen == -1
  143                          */
  144                         sum += su | *(u_char *)w;
  145                         w = (u_short *)((u_char *)w + 1);
  146                         mlen = m->m_len - 1;
  147                         len--;
  148                 } else
  149                         mlen = m->m_len;
  150 skip_start:
  151                 if (len < mlen)
  152                         mlen = len;
  153                 len -= mlen;
  154                 /*
  155                  * Force to a 8-byte boundary first so that we can use
  156                  * LD64_ADD32.
  157                  */
  158                 if (((u_long)w & 7) != 0) {
  159                         REDUCE(sum, tmp);
  160                         if (((u_long)w & 1) != 0 && mlen >= 1) {
  161                                 sum <<= 8;
  162                                 su = *(u_char *)w << 8;
  163                                 w = (u_short *)((u_char *)w + 1);
  164                                 mlen--;
  165                                 byte_swapped = 1;
  166                         }
  167                         if (((u_long)w & 2) != 0 && mlen >= 2) {
  168                                 sum += *w++;
  169                                 mlen -= 2;
  170                         }
  171                         if (((u_long)w & 4) != 0 && mlen >= 4) {
  172                                 LD32_ADD32(sum, tmp, w, 0, cc);
  173                                 MOP(sum);
  174                                 w += 2;
  175                                 mlen -= 4;
  176                         }
  177                 }
  178                 /*
  179                  * Do as much of the checksum as possible 64 bits at at time.
  180                  * In fact, this loop is unrolled to make overhead from
  181                  * branches &c small.
  182                  */
  183                 for (; mlen >= 64; mlen -= 64) {
  184                         LD64_ADD32(sum, tmp, w, 0, cc);
  185                         LD64_ADD32(sum, tmp, w, 8, ccc);
  186                         LD64_ADD32(sum, tmp, w, 16, ccc);
  187                         LD64_ADD32(sum, tmp, w, 24, ccc);
  188                         LD64_ADD32(sum, tmp, w, 32, ccc);
  189                         LD64_ADD32(sum, tmp, w, 40, ccc);
  190                         LD64_ADD32(sum, tmp, w, 48, ccc);
  191                         LD64_ADD32(sum, tmp, w, 56, ccc);
  192                         MOP(sum);
  193                         w += 32;
  194                 }
  195                 if (mlen >= 32) {
  196                         LD64_ADD32(sum, tmp, w, 0, cc);
  197                         LD64_ADD32(sum, tmp, w, 8, ccc);
  198                         LD64_ADD32(sum, tmp, w, 16, ccc);
  199                         LD64_ADD32(sum, tmp, w, 24, ccc);
  200                         MOP(sum);
  201                         w += 16;
  202                         mlen -= 32;
  203                 }
  204                 if (mlen >= 16) {
  205                         LD64_ADD32(sum, tmp, w, 0, cc);
  206                         LD64_ADD32(sum, tmp, w, 8, ccc);
  207                         MOP(sum);
  208                         w += 8;
  209                         mlen -= 16;
  210                 }
  211                 if (mlen >= 8) {
  212                         LD64_ADD32(sum, tmp, w, 0, cc);
  213                         MOP(sum);
  214                         w += 4;
  215                         mlen -= 8;
  216                 }
  217                 REDUCE(sum, tmp);
  218                 while ((mlen -= 2) >= 0)
  219                         sum += *w++;
  220                 if (byte_swapped) {
  221                         sum <<= 8;
  222                         byte_swapped = 0;
  223                         if (mlen == -1) {
  224                                 su |= *(u_char *)w;
  225                                 sum += su;
  226                                 mlen = 0;
  227                         } else
  228                                 mlen = -1;
  229                 } else if (mlen == -1) {
  230                         /*
  231                          * This mbuf has odd number of bytes.
  232                          * There could be a word split betwen
  233                          * this mbuf and the next mbuf.
  234                          * Save the last byte (to prepend to next mbuf).
  235                          */
  236                         su = *(u_char *)w << 8;
  237                 }
  238         }
  239 
  240         if (len)
  241                 printf("%s: out of data by %d\n", __func__, len);
  242         if (mlen == -1) {
  243                 /* The last mbuf has odd # of bytes. Follow the
  244                    standard (the odd byte is shifted left by 8 bits) */
  245                 sum += su & 0xff00;
  246         }
  247         REDUCE(sum, tmp);
  248         return (~sum & 0xffff);
  249 }
Cache object: 47fccae24321abb6fed6c4b927741059
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FreeBSD/Linux Kernel Cross Reference sys/sparc64/sparc64/in_cksum.c

FreeBSD/Linux Kernel Cross Reference
sys/sparc64/sparc64/in_cksum.c
