The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/sparc64/sparc64/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 
   58 #include <sys/cdefs.h>
   59 __FBSDID("$FreeBSD$");
   60 
   61 #include <sys/param.h>
   62 #include <sys/systm.h>
   63 #include <sys/mbuf.h>
   64 
   65 #include <netinet/in.h>
   66 #include <netinet/in_systm.h>
   67 #include <netinet/ip.h>
   68 
   69 #include <machine/in_cksum.h>
   70 
   71 /*
   72  * Checksum routine for Internet Protocol family headers.
   73  *
   74  * This routine is very heavily used in the network
   75  * code and should be modified for each CPU to be as fast as possible.
   76  *
   77  * This implementation is a sparc64 version.  Most code was taken over
   78  * and adapted from the i386.  Some optimizations were changed to achieve
   79  * (hopefully) better performance.
   80  * This uses 64-bit loads, but 32-bit additions due to the lack of a 64-bit
   81  * add-with-carry operation.
   82  */
   83 
   84 /*
   85  * REDUCE() is actually not used that frequently... maybe a C implementation
   86  * would suffice.
   87  */
   88 #define REDUCE(sum, tmp) __asm(                                         \
   89         "sll %2, 16, %1\n"                                              \
   90         "addcc %2, %1, %0\n"                                            \
   91         "srl %0, 16, %0\n"                                              \
   92         "addc %0, 0, %0" : "=r" (sum), "=&r" (tmp) : "" (sum) : "cc")
   93 
   94 /*
   95  * Note that some of these macros depend on the flags being preserved
   96  * between calls, thus they have to be used within a single __asm().
   97  */
   98 #define LD64_ADD32(n, mod)                                              \
   99         "ldx [%3 + " #n "], %1\n"                                       \
  100         "add" #mod " %2, %1, %0\n"                                      \
  101         "srlx %1, 32, %1\n"                                             \
  102         "addccc %0, %1, %0\n"
  103 
  104 #define LD32_ADD32(n, mod)                                              \
  105         "lduw [%3 + " #n "], %1\n"                                      \
  106         "add" #mod " %2, %1, %0\n"
  107 
  108 #define MOP(sum, tmp, addr)                                             \
  109         "addc %2, 0, %0"                                                \
  110         : "=r" (sum), "=&r" (tmp) : "" (sum), "r" (addr) : "cc"
  111 
  112 u_short
  113 in_cksum_skip(struct mbuf *m, int len, int skip)
  114 {
  115         u_short *w;
  116         unsigned long tmp, sum = 0;
  117         int mlen = 0;
  118         int byte_swapped = 0;
  119         u_short su = 0;
  120 
  121         len -= skip;
  122         for (; skip > 0 && m != NULL; m = m->m_next) {
  123                 if (m->m_len > skip) {
  124                         mlen = m->m_len - skip;
  125                         w = (u_short *)(mtod(m, u_char *) + skip);
  126                         goto skip_start;
  127                 } else
  128                         skip -= m->m_len;
  129         }
  130 
  131         for (; m != NULL && len > 0; m = m->m_next) {
  132                 if (m->m_len == 0)
  133                         continue;
  134                 w = mtod(m, u_short *);
  135                 if (mlen == -1) {
  136                         /*
  137                          * The first byte of this mbuf is the continuation
  138                          * of a word spanning between this mbuf and the
  139                          * last mbuf.
  140                          *
  141                          * The high order byte of su is already saved when
  142                          * scanning previous mbuf.  sum was REDUCEd when we
  143                          * found mlen == -1
  144                          */
  145                         sum += su | *(u_char *)w;
  146                         w = (u_short *)((u_char *)w + 1);
  147                         mlen = m->m_len - 1;
  148                         len--;
  149                 } else
  150                         mlen = m->m_len;
  151 skip_start:
  152                 if (len < mlen)
  153                         mlen = len;
  154                 len -= mlen;
  155                 /*
  156                  * Force to a 8-byte boundary first so that we can use
  157                  * LD64_ADD32.
  158                  */
  159                 if (((u_long)w & 7) != 0) {
  160                         REDUCE(sum, tmp);
  161                         if (((u_long)w & 1) != 0 && mlen >= 1) {
  162                                 sum <<= 8;
  163                                 su = *(u_char *)w << 8;
  164                                 w = (u_short *)((u_char *)w + 1);
  165                                 mlen--;
  166                                 byte_swapped = 1;
  167                         }
  168                         if (((u_long)w & 2) != 0 && mlen >= 2) {
  169                                 sum += *w++;
  170                                 mlen -= 2;
  171                         }
  172                         if (((u_long)w & 4) != 0 && mlen >= 4) {
  173                                 __asm(
  174                                     LD32_ADD32(0, cc)
  175                                     MOP(sum, tmp, w)
  176                                 );
  177                                 w += 2;
  178                                 mlen -= 4;
  179                         }
  180                 }
  181                 /*
  182                  * Do as much of the checksum as possible 64 bits at at time.
  183                  * In fact, this loop is unrolled to make overhead from
  184                  * branches &c small.
  185                  */
  186                 for (; mlen >= 64; mlen -= 64) {
  187                         __asm(
  188                             LD64_ADD32(0, cc)
  189                             LD64_ADD32(8, ccc)
  190                             LD64_ADD32(16, ccc)
  191                             LD64_ADD32(24, ccc)
  192                             LD64_ADD32(32, ccc)
  193                             LD64_ADD32(40, ccc)
  194                             LD64_ADD32(48, ccc)
  195                             LD64_ADD32(56, ccc)
  196                             MOP(sum, tmp, w)
  197                         );
  198                         w += 32;
  199                 }
  200                 if (mlen >= 32) {
  201                         __asm(
  202                             LD64_ADD32(0, cc)
  203                             LD64_ADD32(8, ccc)
  204                             LD64_ADD32(16, ccc)
  205                             LD64_ADD32(24, ccc)
  206                             MOP(sum, tmp, w)
  207                         );
  208                         w += 16;
  209                         mlen -= 32;
  210                 }
  211                 if (mlen >= 16) {
  212                         __asm(
  213                             LD64_ADD32(0, cc)
  214                             LD64_ADD32(8, ccc)
  215                             MOP(sum, tmp, w)
  216                         );
  217                         w += 8;
  218                         mlen -= 16;
  219                 }
  220                 if (mlen >= 8) {
  221                         __asm(
  222                             LD64_ADD32(0, cc)
  223                             MOP(sum, tmp, w)
  224                         );
  225                         w += 4;
  226                         mlen -= 8;
  227                 }
  228                 REDUCE(sum, tmp);
  229                 while ((mlen -= 2) >= 0)
  230                         sum += *w++;
  231                 if (byte_swapped) {
  232                         sum <<= 8;
  233                         byte_swapped = 0;
  234                         if (mlen == -1) {
  235                                 su |= *(u_char *)w;
  236                                 sum += su;
  237                                 mlen = 0;
  238                         } else
  239                                 mlen = -1;
  240                 } else if (mlen == -1) {
  241                         /*
  242                          * This mbuf has odd number of bytes.
  243                          * There could be a word split between
  244                          * this mbuf and the next mbuf.
  245                          * Save the last byte (to prepend to next mbuf).
  246                          */
  247                         su = *(u_char *)w << 8;
  248                 }
  249         }
  250 
  251         if (len)
  252                 printf("%s: out of data by %d\n", __func__, len);
  253         if (mlen == -1) {
  254                 /*
  255                  * The last mbuf has odd # of bytes.  Follow the
  256                  * standard (the odd byte is shifted left by 8 bits).
  257                  */
  258                 sum += su & 0xff00;
  259         }
  260         REDUCE(sum, tmp);
  261         return (~sum & 0xffff);
  262 }

Cache object: 1b73be995fa22e4974aac94ac0100010


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