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in6_cksum: avoid using -> operator and use (char *) arithmetics instead. 

reviewed by Joerg Sonnenberger.  he pointed out that the original code
was written that way so that the compiler will explicitly not assume that
the alignment of the data is correct.  although i don't know if it really
matters or not, being safer is not a problem.
This commit is contained in:
yamt 2008-03-10 22:29:13 +00:00
parent d8788e7fd7
commit 15b5bc3e70
1 changed files with 6 additions and 4 deletions
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10
sys/netinet6/in6_cksum.c
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@ -1,4 +1,4 @@
/* $NetBSD: in6_cksum.c,v 1.25 2008/03/09 22:05:50 yamt Exp $ */
/* $NetBSD: in6_cksum.c,v 1.26 2008/03/10 22:29:13 yamt Exp $ */
/*-
* Copyright (c) 2008 Joerg Sonnenberger <joerg@NetBSD.org>.
@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: in6_cksum.c,v 1.25 2008/03/09 22:05:50 yamt Exp $");
__KERNEL_RCSID(0, "$NetBSD: in6_cksum.c,v 1.26 2008/03/10 22:29:13 yamt Exp $");
#include <sys/param.h>
#include <sys/mbuf.h>
@ -58,6 +58,7 @@ in6_cksum(struct mbuf *m, u_int8_t nxt, uint32_t off, uint32_t len)
const struct ip6_hdr *ip6;
uint32_t sum;
const uint16_t *w;
const char *cp;
if (__predict_false(off < sizeof(struct ip6_hdr)))
panic("in6_cksum: offset too short for IPv6 header");
@ -86,8 +87,9 @@ in6_cksum(struct mbuf *m, u_int8_t nxt, uint32_t off, uint32_t len)
#else
sum = (len & 0xffff) + ((len >> 16) & 0xffff) + nxt;
#endif
ip6 = mtod(m, const struct ip6_hdr *);
w = (const uint16_t *)(const void *)&ip6->ip6_src;
cp = mtod(m, const char *);
w = (const uint16_t *)(cp + offsetof(struct ip6_hdr, ip6_src));
ip6 = (const void *)cp;
if (__predict_true((uintptr_t)w % 2 == 0)) {
in6_src = &ip6->ip6_src;
in6_dst = &ip6->ip6_dst;