bsd/netinet6/in6_cksum.c

   1 /*
   2  * Copyright (c) 2009 Apple 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 /*
  30  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
  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  * 3. Neither the name of the project nor the names of its contributors
  42  *    may be used to endorse or promote products derived from this software
  43  *    without specific prior written permission.
  44  *
  45  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  46  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  47  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  48  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  49  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  50  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  51  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  52  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  53  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  54  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  55  * SUCH DAMAGE.
  56  */
  57
  58 /*
  59  * Copyright (c) 1988, 1992, 1993
  60  *      The Regents of the University of California.  All rights reserved.
  61  *
  62  * Redistribution and use in source and binary forms, with or without
  63  * modification, are permitted provided that the following conditions
  64  * are met:
  65  * 1. Redistributions of source code must retain the above copyright
  66  *    notice, this list of conditions and the following disclaimer.
  67  * 2. Redistributions in binary form must reproduce the above copyright
  68  *    notice, this list of conditions and the following disclaimer in the
  69  *    documentation and/or other materials provided with the distribution.
  70  * 3. All advertising materials mentioning features or use of this software
  71  *    must display the following acknowledgement:
  72  *      This product includes software developed by the University of
  73  *      California, Berkeley and its contributors.
  74  * 4. Neither the name of the University nor the names of its contributors
  75  *    may be used to endorse or promote products derived from this software
  76  *    without specific prior written permission.
  77  *
  78  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  79  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  80  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  81  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  82  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  83  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  84  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  85  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  86  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  87  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  88  * SUCH DAMAGE.
  89  *
  90  *      @(#)in_cksum.c  8.1 (Berkeley) 6/10/93
  91  */
  92
  93 /*-
  94  * Copyright (c) 2008 Joerg Sonnenberger <joerg@NetBSD.org>.
  95  * All rights reserved.
  96  *
  97  * Redistribution and use in source and binary forms, with or without
  98  * modification, are permitted provided that the following conditions
  99  * are met:
 100  *
 101  * 1. Redistributions of source code must retain the above copyright
 102  *    notice, this list of conditions and the following disclaimer.
 103  * 2. Redistributions in binary form must reproduce the above copyright
 104  *    notice, this list of conditions and the following disclaimer in
 105  *    the documentation and/or other materials provided with the
 106  *    distribution.
 107  *
 108  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 109  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 110  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 111  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 112  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 113  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
 114  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 115  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 116  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 117  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 118  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 119  * SUCH DAMAGE.
 120  */
 121
 122 #include <sys/param.h>
 123 #include <sys/mbuf.h>
 124 #include <sys/systm.h>
 125 #include <kern/debug.h>
 126 #include <netinet/in.h>
 127 #include <netinet/ip6.h>
 128
 129 #include <net/net_osdep.h>
 130
 131 #include <machine/endian.h>
 132
 133
 134
 135 /*
 136  * Checksum routine for Internet Protocol family headers (Portable Version).
 137  *
 138  * This routine is very heavily used in the network
 139  * code and should be modified for each CPU to be as fast as possible.
 140  */
 141
 142 #define ADDCARRY(x)  do { if (x > 65535) { x -= 65535; } } while (0)
 143 #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);}
 144
 145 /*
 146  * m MUST contain a continuous IP6 header.
 147  * off is a offset where TCP/UDP/ICMP6 header starts.
 148  * len is a total length of a transport segment.
 149  * (e.g. TCP header + TCP payload)
 150  */
 151
 152 u_int16_t
 153 inet6_cksum(struct mbuf *m, unsigned int nxt, unsigned int off,
 154     unsigned int len)
 155 {
 156         u_int16_t *w;
 157         int sum = 0;
 158         int mlen = 0;
 159         int byte_swapped = 0;
 160         struct ip6_hdr *ip6;
 161         union {
 162                 u_int16_t phs[4];
 163                 struct {
 164                         u_int32_t       ph_len;
 165                         u_int8_t        ph_zero[3];
 166                         u_int8_t        ph_nxt;
 167                 } ph __attribute__((__packed__));
 168         } uph;
 169         union {
 170                 u_int8_t        c[2];
 171                 u_int16_t       s;
 172         } s_util;
 173         union {
 174                 u_int16_t s[2];
 175                 u_int32_t l;
 176         } l_util;
 177
 178         /* sanity check */
 179         if ((m->m_flags & M_PKTHDR) && m->m_pkthdr.len < off + len) {
 180                 panic("inet6_cksum: mbuf len (%d) < off+len (%d+%d)\n",
 181                     m->m_pkthdr.len, off, len);
 182         }
 183
 184         if (nxt != 0) {
 185                 bzero(&uph, sizeof (uph));
 186
 187                 /*
 188                  * First create IP6 pseudo header and calculate a summary.
 189                  */
 190                 ip6 = mtod(m, struct ip6_hdr *);
 191                 w = (u_int16_t *)&ip6->ip6_src;
 192                 uph.ph.ph_len = htonl(len);
 193                 uph.ph.ph_nxt = nxt;
 194
 195                 /* IPv6 source address */
 196                 sum += w[0];
 197                 if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src))
 198                         sum += w[1];
 199                 sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5];
 200                 sum += w[6]; sum += w[7];
 201                 /* IPv6 destination address */
 202                 sum += w[8];
 203                 if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst))
 204                         sum += w[9];
 205                 sum += w[10]; sum += w[11]; sum += w[12]; sum += w[13];
 206                 sum += w[14]; sum += w[15];
 207                 /* Payload length and upper layer identifier */
 208                 sum += uph.phs[0];  sum += uph.phs[1];
 209                 sum += uph.phs[2];  sum += uph.phs[3];
 210         }
 211
 212         /*
 213          * Secondly calculate a summary of the first mbuf excluding offset.
 214          */
 215         while (m != NULL && off > 0) {
 216                 if (m->m_len <= off)
 217                         off -= m->m_len;
 218                 else
 219                         break;
 220                 m = m->m_next;
 221         }
 222         w = (u_int16_t *)(mtod(m, u_char *) + off);
 223         mlen = m->m_len - off;
 224         if (len < mlen)
 225                 mlen = len;
 226         len -= mlen;
 227         /*
 228          * Force to even boundary.
 229          */
 230         if ((1 & (intptr_t) w) && (mlen > 0)) {
 231                 REDUCE;
 232                 sum <<= 8;
 233                 s_util.c[0] = *(u_char *)w;
 234                 w = (u_int16_t *)((char *)w + 1);
 235                 mlen--;
 236                 byte_swapped = 1;
 237         }
 238         /*
 239          * Unroll the loop to make overhead from
 240          * branches &c small.
 241          */
 242         while ((mlen -= 32) >= 0) {
 243                 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
 244                 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
 245                 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
 246                 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
 247                 w += 16;
 248         }
 249         mlen += 32;
 250         while ((mlen -= 8) >= 0) {
 251                 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
 252                 w += 4;
 253         }
 254         mlen += 8;
 255         if (mlen == 0 && byte_swapped == 0)
 256                 goto next;
 257         REDUCE;
 258         while ((mlen -= 2) >= 0) {
 259                 sum += *w++;
 260         }
 261         if (byte_swapped) {
 262                 REDUCE;
 263                 sum <<= 8;
 264                 byte_swapped = 0;
 265                 if (mlen == -1) {
 266                         s_util.c[1] = *(char *)w;
 267                         sum += s_util.s;
 268                         mlen = 0;
 269                 } else
 270                         mlen = -1;
 271         } else if (mlen == -1)
 272                 s_util.c[0] = *(char *)w;
 273  next:
 274         m = m->m_next;
 275
 276         /*
 277          * Lastly calculate a summary of the rest of mbufs.
 278          */
 279
 280         for (;m && len; m = m->m_next) {
 281                 if (m->m_len == 0)
 282                         continue;
 283                 w = mtod(m, u_int16_t *);
 284                 if (mlen == -1) {
 285                         /*
 286                          * The first byte of this mbuf is the continuation
 287                          * of a word spanning between this mbuf and the
 288                          * last mbuf.
 289                          *
 290                          * s_util.c[0] is already saved when scanning previous
 291                          * mbuf.
 292                          */
 293                         s_util.c[1] = *(char *)w;
 294                         sum += s_util.s;
 295                         w = (u_int16_t *)((char *)w + 1);
 296                         mlen = m->m_len - 1;
 297                         len--;
 298                 } else
 299                         mlen = m->m_len;
 300                 if (len < mlen)
 301                         mlen = len;
 302                 len -= mlen;
 303                 /*
 304                  * Force to even boundary.
 305                  */
 306                 if ((1 & (intptr_t) w) && (mlen > 0)) {
 307                         REDUCE;
 308                         sum <<= 8;
 309                         s_util.c[0] = *(u_char *)w;
 310                         w = (u_int16_t *)((char *)w + 1);
 311                         mlen--;
 312                         byte_swapped = 1;
 313                 }
 314                 /*
 315                  * Unroll the loop to make overhead from
 316                  * branches &c small.
 317                  */
 318                 while ((mlen -= 32) >= 0) {
 319                         sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
 320                         sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
 321                         sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
 322                         sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
 323                         w += 16;
 324                 }
 325                 mlen += 32;
 326                 while ((mlen -= 8) >= 0) {
 327                         sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
 328                         w += 4;
 329                 }
 330                 mlen += 8;
 331                 if (mlen == 0 && byte_swapped == 0)
 332                         continue;
 333                 REDUCE;
 334                 while ((mlen -= 2) >= 0) {
 335                         sum += *w++;
 336                 }
 337                 if (byte_swapped) {
 338                         REDUCE;
 339                         sum <<= 8;
 340                         byte_swapped = 0;
 341                         if (mlen == -1) {
 342                                 s_util.c[1] = *(char *)w;
 343                                 sum += s_util.s;
 344                                 mlen = 0;
 345                         } else
 346                                 mlen = -1;
 347                 } else if (mlen == -1)
 348                         s_util.c[0] = *(char *)w;
 349         }
 350         if (len)
 351                 printf("inet6_cksum: out of data by %d\n", len);
 352         if (mlen == -1) {
 353                 /* The last mbuf has odd # of bytes. Follow the
 354                    standard (the odd byte may be shifted left by 8 bits
 355                    or not as determined by endian-ness of the machine) */
 356                 s_util.c[1] = 0;
 357                 sum += s_util.s;
 358         }
 359         REDUCE;
 360         return (~sum & 0xffff);
 361 }
 362