[src/trunk]: src/usr.sbin/tcpdump fix the cksum routine and parse ESH packets.

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

details:   https://anonhg.NetBSD.org/src/rev/15abed6badb1
branches:  trunk
changeset: 471554:15abed6badb1
user:      chopps <chopps%NetBSD.org@localhost>
date:      Mon Apr 05 00:58:29 1999 +0000

description:
fix the cksum routine and parse ESH packets.

diffstat:

 usr.sbin/tcpdump/print-isoclns.c |  70 +++++++++++++++++++++++++--------------
 1 files changed, 44 insertions(+), 26 deletions(-)

diffs (113 lines):

diff -r 0ce8689459cf -r 15abed6badb1 usr.sbin/tcpdump/print-isoclns.c
--- a/usr.sbin/tcpdump/print-isoclns.c  Mon Apr 05 00:22:47 1999 +0000
+++ b/usr.sbin/tcpdump/print-isoclns.c  Mon Apr 05 00:58:29 1999 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: print-isoclns.c,v 1.4 1997/10/03 19:55:21 christos Exp $       */
+/*     $NetBSD: print-isoclns.c,v 1.5 1999/04/05 00:58:29 chopps Exp $ */
 
 /*
  * Copyright (c) 1992, 1993, 1994, 1995, 1996
@@ -29,7 +29,7 @@
 static const char rcsid[] =
     "@(#) Header: print-isoclns.c,v 1.15 96/12/31 21:27:41 leres Exp  (LBL)";
 #else
-__RCSID("$NetBSD: print-isoclns.c,v 1.4 1997/10/03 19:55:21 christos Exp $");
+__RCSID("$NetBSD: print-isoclns.c,v 1.5 1999/04/05 00:58:29 chopps Exp $");
 #endif
 #endif
 
@@ -231,11 +231,27 @@
                li = ep - p;
                break;
        }
-#if 0
-       case ESIS_ESH:
-               printf(" esh");
+       case ESIS_ESH: {
+               const u_char *nsap;
+               int i, nnsaps;
+
+               nnsaps = *p++;
+
+               /* print NSAPs */
+               for (i = 0; i < nnsaps; i++) {
+                       nsap = p;
+                       p += *p + 1;
+                       if (p > ep) {
+                               printf(" [bad li]");
+                               return;
+                       }
+                       if (p > snapend)
+                               return;
+                       printf(" nsap %s", isonsap_string(nsap));
+               }
+               li = ep - p;
                break;
-#endif
+       }
        case ESIS_ISH: {
                const u_char *is;
 
@@ -246,7 +262,7 @@
                }
                if (p > snapend)
                        return;
-               printf(" %s", isonsap_string(is));
+               printf(" net %s", isonsap_string(is));
                li = ep - p;
                break;
        }
@@ -297,32 +313,34 @@
 osi_cksum(register const u_char *p, register u_int len,
          const u_char *toff, u_char *cksum, u_char *off)
 {
-       int x, y, f = (len - ((toff - p) + 1));
-       int32_t c0 = 0, c1 = 0;
+       const u_char *ep;
+       int c0, c1;
+       int n;
 
        if ((cksum[0] = off[0]) == 0 && (cksum[1] = off[1]) == 0)
                return 0;
 
-       off[0] = off[1] = 0;
-       while ((int)--len >= 0) {
-               c0 += *p++;
+       n = toff - p + 1;
+       c0 = c1 = 0;
+       ep = p + len;
+       for (; p < toff; p++) {
+               c0 = (c0 + *p);
                c1 += c0;
-               c0 %= 255;
-               c1 %= 255;
        }
-       x = (c0 * f - c1);
-       if (x < 0)
-               x = 255 - (-x % 255);
-       else
-               x %= 255;
-       y = -1 * (x + c0);
-       if (y < 0)
-               y = 255 - (-y % 255);
-       else
-               y %= 255;
+
+       /* skip cksum bytes */
+       p += 2;         
+       c1 += c0; c1 += c0;
 
-       off[0] = x;
-       off[1] = y;
+       for (; p < ep; p++) {
+               c0 = (c0 + *p);
+               c1 += c0;
+       }
+
+       c1 = (((c0 * (len - n)) - c1) % 255);
+       cksum[0] = (u_char) ((c1 < 0) ? c1 + 255 : c1);
+       c1 = (-(int) (c1 + c0)) % 255;
+       cksum[1] = (u_char) (c1 < 0 ? c1 + 255 : c1);
 
        return (off[0] != cksum[0] || off[1] != cksum[1]);
 }