sys/arch/vax/vax/in4_cksum.c

   1 /*      $NetBSD: in4_cksum.c,v 1.11 2006/12/31 10:52:52 ragge Exp $     */
   2
   3 /*
   4  * Copyright (C) 1999 WIDE Project.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the project nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 /*
  33  * Copyright (c) 1988, 1992, 1993
  34  *      The Regents of the University of California.  All rights reserved.
  35  *
  36  * Redistribution and use in source and binary forms, with or without
  37  * modification, are permitted provided that the following conditions
  38  * are met:
  39  * 1. Redistributions of source code must retain the above copyright
  40  *    notice, this list of conditions and the following disclaimer.
  41  * 2. Redistributions in binary form must reproduce the above copyright
  42  *    notice, this list of conditions and the following disclaimer in the
  43  *    documentation and/or other materials provided with the distribution.
  44  * 3. 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/cdefs.h>
  64 __KERNEL_RCSID(0, "$NetBSD: in4_cksum.c,v 1.11 2006/12/31 10:52:52 ragge Exp $");
  65
  66 #include <sys/param.h>
  67 #include <sys/mbuf.h>
  68 #include <sys/systm.h>
  69 #include <sys/socket.h>
  70 #include <net/route.h>
  71 #include <netinet/in.h>
  72 #include <netinet/in_systm.h>
  73 #include <netinet/ip.h>
  74 #include <netinet/ip_var.h>
  75
  76 #ifdef CKSUMDEBUG
  77 int in4_cksum_md_debug(struct mbuf *m, uint8_t nxt, int off, int len);
  78 #define in4_cksum in4_cksum_md_debug
  79 #include <netinet/in4_cksum.c>
  80 #undef in4_cksum
  81 #undef ADDCARRY
  82 #undef REDUCE
  83 #endif
  84
  85 /*
  86  * Checksum routine for Internet Protocol family headers.
  87  * This is only for IPv4 pseudo header checksum.
  88  * No need to clear non-pseudo-header fields in IPv4 header.
  89  * len is for actual payload size, and does not include IPv4 header and
  90  * skipped header chain (off + len should be equal to the whole packet).
  91  *
  92  * This implementation is VAX version.
  93  */
  94
  95
  96 #define REDUCE          {sum = (sum & 0xffff) + (sum >> 16);}
  97 #define ADDCARRY        {if (sum > 0xffff) sum -= 0xffff;}
  98 #define ADVANCE(n)      {w += n; mlen -= n;}
  99 #define SWAP            {sum <<= 8;}            /* depends on recent REDUCE */
 100
 101 #define Asm     __asm volatile
 102 #define ADDL    Asm("addl2 (%0)+,%1": "=r" (w), "=r" (sum): "0" (w), "1" (sum))
 103 #define ADWC    Asm("adwc  (%0)+,%1": "=r" (w), "=r" (sum): "0" (w), "1" (sum))
 104 #define ADDC    Asm("adwc     $0,%0" : "=r" (sum) : "0" (sum))
 105 #define UNSWAP  Asm("rotl  $8,%0,%0" : "=r" (sum) : "0" (sum))
 106 #define ADDBYTE {sum += *w; SWAP; byte_swapped ^= 1;}
 107 #define ADDWORD {sum += *(uint16_t *)w;}
 108
 109 int
 110 in4_cksum(struct mbuf *m, uint8_t nxt, int off, int len)
 111 {
 112         uint8_t *w;
 113         uint32_t sum = 0;
 114         int mlen = 0;
 115         int byte_swapped = 0;
 116 #ifdef CKSUMDEBUG
 117         int debugrv = in4_cksum_md_debug(m, nxt, off, len);
 118 #endif
 119
 120         if (nxt != 0) {
 121 #ifdef DIAGNOSTIC
 122                 if (off < sizeof(struct ipovly))
 123                         panic("in4_cksum: offset too short");
 124                 if (m->m_len < sizeof(struct ip))
 125                         panic("in4_cksum: bad mbuf chain");
 126 #endif
 127
 128                 __asm volatile(
 129                         "movzwl 16(%%ap),%0;"   /* mov len to sum */
 130                         "addb2  8(%%ap),%0;"    /* add proto to sum */
 131                         "rotl   $8,%0,%0;"      /* htons, carry is preserved */
 132                         "adwc   12(%2),%0;"     /* add src ip */
 133                         "adwc   16(%2),%0;"     /* add dst ip */
 134                         "adwc   $0,%0;"         /* clean up carry */
 135                         : "=r" (sum)
 136                         : "0" (sum), "r" (mtod(m, void *)));
 137         }
 138
 139         /* skip unnecessary part */
 140         while (m && off > 0) {
 141                 if (m->m_len > off)
 142                         break;
 143                 off -= m->m_len;
 144                 m = m->m_next;
 145         }
 146
 147         for (;m && len; m = m->m_next) {
 148                 if ((mlen = m->m_len) == 0)
 149                         continue;
 150                 w = mtod(m, uint8_t *);
 151                 if (off) {
 152                         w += off;
 153                         mlen -= off;
 154                         off = 0;
 155                 }
 156                 if (len < mlen)
 157                         mlen = len;
 158                 len -= mlen;
 159                 if (mlen < 16)
 160                         goto short_mbuf;
 161                 /*
 162                  * Ensure that we're aligned on a word boundary here so
 163                  * that we can do 32 bit operations below.
 164                  */
 165                 if ((3 & (intptr_t) w) != 0) {
 166                         REDUCE;
 167                         if ((1 & (intptr_t) w) != 0) {
 168                                 ADDBYTE;
 169                                 ADVANCE(1);
 170                         }
 171                         if ((2 & (intptr_t) w) != 0) {
 172                                 ADDWORD;
 173                                 ADVANCE(2);
 174                         }
 175                 }
 176                 /*
 177                  * Do as much of the checksum as possible 32 bits at at time.
 178                  * In fact, this loop is unrolled to make overhead from
 179                  * branches &c small.
 180                  */
 181                 while ((mlen -= 32) >= 0) {
 182                         /*
 183                          * Add with carry 16 words and fold in the last carry
 184                          * by adding a 0 with carry.
 185                          */
 186                         ADDL;   ADWC;   ADWC;   ADWC;
 187                         ADWC;   ADWC;   ADWC;   ADWC;
 188                         ADDC;
 189                 }
 190                 mlen += 32;
 191                 if (mlen >= 16) {
 192                         ADDL;   ADWC;   ADWC;   ADWC;
 193                         ADDC;
 194                         mlen -= 16;
 195                 }
 196         short_mbuf:
 197                 if (mlen >= 8) {
 198                         ADDL;   ADWC;
 199                         ADDC;
 200                         mlen -= 8;
 201                 }
 202                 if (mlen >= 4) {
 203                         ADDL;
 204                         ADDC;
 205                         mlen -= 4;
 206                 }
 207                 if (mlen > 0) {
 208                         REDUCE;
 209                         if (mlen >= 2) {
 210                                 ADDWORD;
 211                                 ADVANCE(2);
 212                         }
 213                         if (mlen >= 1) {
 214                                 ADDBYTE;
 215                         }
 216                 }
 217         }
 218
 219         if (len)
 220                 printf("cksum4: out of data\n");
 221         if (byte_swapped) {
 222                 UNSWAP;
 223         }
 224         REDUCE;
 225         ADDCARRY;
 226 #ifdef CKSUMDEBUG
 227         if ((sum ^ 0xffff) != debugrv)
 228                 printf("in4_cksum: rv != debugrv (rv %x debugrv %x)\n",
 229                     (sum ^ 0xffff), debugrv);
 230 #endif
 231         return (sum ^ 0xffff);
 232 }