[src/trunk]: src/usr.sbin/traceroute correct in_cksum2 for odd length case

[itojun <itojun%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/670503f4b1b1
branches:  trunk
changeset: 534666:670503f4b1b1
user:      itojun <itojun%NetBSD.org@localhost>
date:      Thu Aug 01 09:03:50 2002 +0000

description:
correct in_cksum2 for odd length case

diffstat:

 usr.sbin/traceroute/traceroute.c |  20 +++++++++++++-------
 1 files changed, 13 insertions(+), 7 deletions(-)

diffs (54 lines):

diff -r 6b77ecb6f7c5 -r 670503f4b1b1 usr.sbin/traceroute/traceroute.c
--- a/usr.sbin/traceroute/traceroute.c  Thu Aug 01 09:02:18 2002 +0000
+++ b/usr.sbin/traceroute/traceroute.c  Thu Aug 01 09:03:50 2002 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: traceroute.c,v 1.50 2002/08/01 09:02:18 itojun Exp $   */
+/*     $NetBSD: traceroute.c,v 1.51 2002/08/01 09:03:50 itojun Exp $   */
 
 /*
  * Copyright (c) 1988, 1989, 1991, 1994, 1995, 1996, 1997
@@ -29,7 +29,7 @@
 #else
 __COPYRIGHT("@(#) Copyright (c) 1988, 1989, 1991, 1994, 1995, 1996, 1997\n\
 The Regents of the University of California.  All rights reserved.\n");
-__RCSID("$NetBSD: traceroute.c,v 1.50 2002/08/01 09:02:18 itojun Exp $");
+__RCSID("$NetBSD: traceroute.c,v 1.51 2002/08/01 09:03:50 itojun Exp $");
 #endif
 #endif
 
@@ -1398,7 +1398,10 @@
 {
        int nleft = len;
        u_int16_t *w = addr;
-       u_int16_t answer;
+       union {
+               u_int16_t w;
+               u_int8_t b[2];
+       } answer;
        int32_t sum = seed;
 
        /*
@@ -1413,16 +1416,19 @@
        }
 
        /* mop up an odd byte, if necessary */
-       if (nleft == 1)
-               sum += *(u_char *)w;
+       if (nleft == 1) {
+               answer.b[0] = *(u_char *)w;
+               answer.b[1] = 0;
+               sum += answer.w;
+       }
 
        /*
         * add back carry outs from top 16 bits to low 16 bits
         */
        sum = (sum >> 16) + (sum & 0xffff);     /* add hi 16 to low 16 */
        sum += (sum >> 16);                     /* add carry */
-       answer = sum;                           /* truncate to 16 bits */
-       return (answer);
+       answer.w = sum;                         /* truncate to 16 bits */
+       return (answer.w);
 }
 
 /*