Go with Wireshark's Internet checksum routine.

The Wireshark routine is based on the BSD in-kernel portable checksum
routine (thus BSD-licensed); it takes a vector of pointers and lengths
and checksums the concatenation of the buffers in question (just as the
BSD in-kernel routine checksums a chain of mbufs).

This simplifies the "with a pseudo-header" checksums; hopefully it'll
fix up the problems being seen on some big-endian platforms, which might
be due to hand-calculating some or all of the checksum and doing so
incorrectly.  It also gets rid of some code that might be dereferencing
unaligned pointers.

1 files changed, 4 insertions, 1 deletions

diff --git a/print-mobile.c b/print-mobile.c
index 816ffd6e..de4eab1d 100644
--- a/print-mobile.c
+++ b/print-mobile.c
@@ -72,6 +72,7 @@ mobile_print(const u_char *bp, u_int length)
 {
 	const u_char *cp = bp +8 ;
 	const struct mobile_ip *mob;
+	struct cksum_vec vec[1];
 	u_short proto,crc;
 	u_char osp =0;			/* old source address present */
 
@@ -101,7 +102,9 @@ mobile_print(const u_char *bp, u_int length)
 		(void)printf("> %s ",ipaddr_string(&mob->odst));
 		(void)printf("(oproto=%d)",proto>>8);
 	}
-	if (in_cksum((u_short *)mob, osp ? 12 : 8, 0)!=0) {
+	vec[0].ptr = (const u_int8_t *)(void *)mob;
+	vec[0].len = osp ? 12 : 8;
+	if (in_cksum(vec, 1)!=0) {
 		(void)printf(" (bad checksum %d)",crc);
 	}