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in6_cksum.c revision 1.16.16.5
      1  1.16.16.5     yamt /*	$NetBSD: in6_cksum.c,v 1.16.16.5 2008/02/27 08:37:04 yamt Exp $	*/
      2        1.3  thorpej 
      3  1.16.16.5     yamt /*-
      4  1.16.16.5     yamt  * Copyright (c) 2008 Joerg Sonnenberger <joerg (at) NetBSD.org>.
      5        1.2   itojun  * All rights reserved.
      6        1.8   itojun  *
      7        1.2   itojun  * Redistribution and use in source and binary forms, with or without
      8        1.2   itojun  * modification, are permitted provided that the following conditions
      9        1.2   itojun  * are met:
     10        1.8   itojun  *
     11        1.2   itojun  * 1. Redistributions of source code must retain the above copyright
     12        1.2   itojun  *    notice, this list of conditions and the following disclaimer.
     13        1.2   itojun  * 2. Redistributions in binary form must reproduce the above copyright
     14  1.16.16.5     yamt  *    notice, this list of conditions and the following disclaimer in
     15  1.16.16.5     yamt  *    the documentation and/or other materials provided with the
     16  1.16.16.5     yamt  *    distribution.
     17  1.16.16.5     yamt  *
     18  1.16.16.5     yamt  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  1.16.16.5     yamt  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  1.16.16.5     yamt  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     21  1.16.16.5     yamt  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
     22  1.16.16.5     yamt  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     23  1.16.16.5     yamt  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
     24  1.16.16.5     yamt  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     25  1.16.16.5     yamt  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     26  1.16.16.5     yamt  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     27  1.16.16.5     yamt  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     28  1.16.16.5     yamt  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29        1.2   itojun  * SUCH DAMAGE.
     30        1.2   itojun  */
     31       1.12    lukem 
     32       1.12    lukem #include <sys/cdefs.h>
     33  1.16.16.5     yamt __KERNEL_RCSID(0, "$NetBSD: in6_cksum.c,v 1.16.16.5 2008/02/27 08:37:04 yamt Exp $");
     34        1.2   itojun 
     35        1.2   itojun #include <sys/param.h>
     36        1.2   itojun #include <sys/mbuf.h>
     37        1.2   itojun #include <netinet/in.h>
     38        1.7   itojun #include <netinet/ip6.h>
     39        1.6   itojun 
     40        1.2   itojun /*
     41  1.16.16.5     yamt  * Checksum of the IPv6 pseudo header.
     42        1.2   itojun  *
     43  1.16.16.5     yamt  * off is supposed to be the skipped IPv6 header, len is the payload size.
     44        1.2   itojun  */
     45        1.2   itojun 
     46        1.2   itojun int
     47  1.16.16.5     yamt in6_cksum(struct mbuf *m, u_int8_t nxt, uint32_t off, uint32_t len)
     48        1.2   itojun {
     49        1.9   itojun 	union {
     50  1.16.16.5     yamt 		uint16_t words[16];
     51        1.9   itojun 		struct {
     52  1.16.16.5     yamt 			struct in6_addr ip6_src;
     53  1.16.16.5     yamt 			struct in6_addr ip6_dst;
     54  1.16.16.5     yamt 		} addrs;
     55  1.16.16.5     yamt 	} u;
     56  1.16.16.5     yamt 	struct in6_addr *in6_src, *in6_dst;
     57  1.16.16.5     yamt 	uint32_t sum;
     58  1.16.16.5     yamt 	uint16_t *w;
     59  1.16.16.5     yamt 
     60  1.16.16.5     yamt 	if (__predict_false(off < sizeof(struct ip6_hdr)))
     61  1.16.16.5     yamt 		panic("in6_cksum: offset too short for IPv6 header");
     62  1.16.16.5     yamt 	if (__predict_false(m->m_len < sizeof(struct ip6_hdr)))
     63  1.16.16.5     yamt 		panic("in6_cksum: mbuf too short for IPv6 header");
     64        1.9   itojun 
     65       1.11  thorpej 	if (nxt == 0)
     66  1.16.16.5     yamt 		return cpu_in_cksum(m, len, off, 0);
     67        1.2   itojun 
     68        1.2   itojun 	/*
     69  1.16.16.5     yamt 	 * Compute the equivalent of:
     70  1.16.16.5     yamt 	 * struct ip6_hdr_pseudo ip6;
     71  1.16.16.5     yamt 	 *
     72  1.16.16.5     yamt 	 * bzero(sizeof(*ip6));
     73  1.16.16.5     yamt 	 * ip6.ip6ph_nxt = nxt;
     74  1.16.16.5     yamt 	 * ip6.ip6ph_len = htonl(len);
     75  1.16.16.5     yamt 	 * ipv6.ip6ph_src = mtod(m, struct ip6_hdr *)->ip6_src;
     76  1.16.16.5     yamt 	 * in6_clearscope(&ip6->ip6ph_src);
     77  1.16.16.5     yamt 	 * ipv6.ip6ph_dst = mtod(m, struct ip6_hdr *)->ip6_dst;
     78  1.16.16.5     yamt 	 * in6_clearscope(&ip6->ip6ph_dst);
     79  1.16.16.5     yamt 	 * sum = one_add(&ip6);
     80        1.2   itojun 	 */
     81        1.2   itojun 
     82  1.16.16.5     yamt #if BYTE_ORDER == LITTLE_ENDIAN
     83  1.16.16.5     yamt 	sum = ((len & 0xffff) + ((len >> 16) & 0xffff) + nxt) << 8;
     84  1.16.16.5     yamt #else
     85  1.16.16.5     yamt 	sum = (len & 0xffff) + ((len >> 16) & 0xffff) + nxt;
     86  1.16.16.5     yamt #endif
     87  1.16.16.5     yamt 	w = (uint16_t *)(mtod(m, char  *) + offsetof(struct ip6_hdr, ip6_src));
     88  1.16.16.5     yamt 	if (__predict_true((uintptr_t)w % 2 == 0)) {
     89  1.16.16.5     yamt 		in6_src = &mtod(m, struct ip6_hdr *)->ip6_src;
     90  1.16.16.5     yamt 		in6_dst = &mtod(m, struct ip6_hdr *)->ip6_dst;
     91  1.16.16.5     yamt 	} else {
     92  1.16.16.5     yamt 		memcpy(&u, &mtod(m, struct ip6_hdr *)->ip6_src, 32);
     93  1.16.16.5     yamt 		w = u.words;
     94  1.16.16.5     yamt 		in6_src = &u.addrs.ip6_src;
     95  1.16.16.5     yamt 		in6_dst = &u.addrs.ip6_dst;
     96  1.16.16.5     yamt 	}
     97  1.16.16.5     yamt 
     98  1.16.16.5     yamt 	sum += w[0];
     99  1.16.16.5     yamt 	if (!IN6_IS_SCOPE_LINKLOCAL(in6_src) &&
    100  1.16.16.5     yamt 	    !IN6_IS_ADDR_MC_INTFACELOCAL(in6_src))
    101  1.16.16.5     yamt 		sum += w[1];
    102  1.16.16.5     yamt 	sum += w[2];
    103  1.16.16.5     yamt 	sum += w[3];
    104  1.16.16.5     yamt 	sum += w[4];
    105  1.16.16.5     yamt 	sum += w[5];
    106  1.16.16.5     yamt 	sum += w[6];
    107  1.16.16.5     yamt 	sum += w[7];
    108  1.16.16.5     yamt 	w += 8;
    109  1.16.16.5     yamt 	sum += w[0];
    110  1.16.16.5     yamt 	if (!IN6_IS_SCOPE_LINKLOCAL(in6_dst) &&
    111  1.16.16.5     yamt 	    !IN6_IS_ADDR_MC_INTFACELOCAL(in6_dst))
    112  1.16.16.5     yamt 		sum += w[1];
    113  1.16.16.5     yamt 	sum += w[2];
    114  1.16.16.5     yamt 	sum += w[3];
    115  1.16.16.5     yamt 	sum += w[4];
    116  1.16.16.5     yamt 	sum += w[5];
    117  1.16.16.5     yamt 	sum += w[6];
    118  1.16.16.5     yamt 	sum += w[7];
    119        1.2   itojun 
    120  1.16.16.4     yamt 	return cpu_in_cksum(m, len, off, sum);
    121        1.2   itojun }
    122