bsd/netinet6/in6_cksum.c

   1 /*
   2  * Copyright (c) 2009-2012 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 <machine/endian.h>
 124 #include <sys/mbuf.h>
 125 #include <sys/systm.h>
 126 #include <kern/debug.h>
 127 #include <netinet/in.h>
 128 #include <netinet/ip6.h>
 129 #include <netinet6/ip6_var.h>
 130
 131 /*
 132  * Checksum routine for Internet Protocol family headers (Portable Version).
 133  *
 134  * This routine is very heavily used in the network
 135  * code and should be modified for each CPU to be as fast as possible.
 136  */
 137
 138 /*
 139  * Compute IPv6 pseudo-header checksum; assumes 16-bit aligned pointers.
 140  */
 141 uint16_t
 142 in6_pseudo(const struct in6_addr *src, const struct in6_addr *dst, uint32_t x)
 143 {
 144         uint32_t sum = 0;
 145         const uint16_t *w;
 146
 147         /*
 148          * IPv6 source address
 149          */
 150         w = (const uint16_t *)src;
 151         sum += w[0];
 152         if (!IN6_IS_SCOPE_EMBED(src)) {
 153                 sum += w[1];
 154         }
 155         sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5];
 156         sum += w[6]; sum += w[7];
 157
 158         /*
 159          * IPv6 destination address
 160          */
 161         w = (const uint16_t *)dst;
 162         sum += w[0];
 163         if (!IN6_IS_SCOPE_EMBED(dst)) {
 164                 sum += w[1];
 165         }
 166         sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5];
 167         sum += w[6]; sum += w[7];
 168
 169         /*
 170          * Caller-supplied value; 'x' could be one of:
 171          *
 172          *      htonl(proto + length), or
 173          *      htonl(proto + length + sum)
 174          **/
 175         sum += x;
 176
 177         /* fold in carry bits */
 178         ADDCARRY(sum);
 179
 180         return sum;
 181 }
 182
 183 /*
 184  * m MUST contain at least an IPv6 header, if nxt is specified;
 185  * nxt is the upper layer protocol number;
 186  * off is an offset where TCP/UDP/ICMP6 header starts;
 187  * len is a total length of a transport segment (e.g. TCP header + TCP payload)
 188  */
 189 u_int16_t
 190 inet6_cksum(struct mbuf *m, uint32_t nxt, uint32_t off, uint32_t len)
 191 {
 192         uint32_t sum;
 193
 194         sum = m_sum16(m, off, len);
 195
 196         if (nxt != 0) {
 197                 struct ip6_hdr *ip6;
 198                 unsigned char buf[sizeof(*ip6)] __attribute__((aligned(8)));
 199                 uint32_t mlen;
 200
 201                 /*
 202                  * Sanity check
 203                  *
 204                  * Use m_length2() instead of m_length(), as we cannot rely on
 205                  * the caller setting m_pkthdr.len correctly, if the mbuf is
 206                  * a M_PKTHDR one.
 207                  */
 208                 if ((mlen = m_length2(m, NULL)) < sizeof(*ip6)) {
 209                         panic("%s: mbuf %p pkt too short (%d) for IPv6 header",
 210                             __func__, m, mlen);
 211                         /* NOTREACHED */
 212                 }
 213
 214                 /*
 215                  * In case the IPv6 header is not contiguous, or not 32-bit
 216                  * aligned, copy it to a local buffer.  Note here that we
 217                  * expect the data pointer to point to the IPv6 header.
 218                  */
 219                 if ((sizeof(*ip6) > m->m_len) ||
 220                     !IP6_HDR_ALIGNED_P(mtod(m, caddr_t))) {
 221                         m_copydata(m, 0, sizeof(*ip6), (caddr_t)buf);
 222                         ip6 = (struct ip6_hdr *)(void *)buf;
 223                 } else {
 224                         ip6 = (struct ip6_hdr *)(void *)(m->m_data);
 225                 }
 226
 227                 /* add pseudo header checksum */
 228                 sum += in6_pseudo(&ip6->ip6_src, &ip6->ip6_dst,
 229                     htonl(nxt + len));
 230
 231                 /* fold in carry bits */
 232                 ADDCARRY(sum);
 233         }
 234
 235         return ~sum & 0xffff;
 236 }
 237
 238 /*
 239  * buffer MUST contain at least an IPv6 header, if nxt is specified;
 240  * nxt is the upper layer protocol number;
 241  * off is an offset where TCP/UDP/ICMP6 header starts;
 242  * len is a total length of a transport segment (e.g. TCP header + TCP payload)
 243  */
 244 u_int16_t
 245 inet6_cksum_buffer(const uint8_t *buffer, uint32_t nxt, uint32_t off,
 246     uint32_t len)
 247 {
 248         uint32_t sum;
 249
 250         if (off >= len) {
 251                 panic("%s: off (%d) >= len (%d)", __func__, off, len);
 252         }
 253
 254         sum = b_sum16(&((const uint8_t *)buffer)[off], len);
 255
 256         if (nxt != 0) {
 257                 const struct ip6_hdr *ip6;
 258                 unsigned char buf[sizeof(*ip6)] __attribute__((aligned(8)));
 259
 260                 /*
 261                  * In case the IPv6 header is not contiguous, or not 32-bit
 262                  * aligned, copy it to a local buffer.  Note here that we
 263                  * expect the data pointer to point to the IPv6 header.
 264                  */
 265                 if (!IP6_HDR_ALIGNED_P(buffer)) {
 266                         memcpy(buf, buffer, sizeof(*ip6));
 267                         ip6 = (const struct ip6_hdr *)(const void *)buf;
 268                 } else {
 269                         ip6 = (const struct ip6_hdr *)buffer;
 270                 }
 271
 272                 /* add pseudo header checksum */
 273                 sum += in6_pseudo(&ip6->ip6_src, &ip6->ip6_dst,
 274                     htonl(nxt + len));
 275
 276                 /* fold in carry bits */
 277                 ADDCARRY(sum);
 278         }
 279
 280         return ~sum & 0xffff;
 281 }