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/* packet-null.c
* Routines for null packet disassembly
*
* $Id: packet-null.c,v 1.2 1998/09/27 22:12:33 gerald Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@zing.org>
*
* This file created and by Mike Hall <mlh@io.com>
* Copyright 1998
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#include <gtk/gtk.h>
#include <stdio.h>
#include <sys/socket.h>
#include <pcap.h>
#include "ethereal.h"
#include "packet.h"
void
dissect_null( const u_char *pd, frame_data *fd, GtkTree *tree ) {
e_nullhdr nh;
GtkWidget *ti, *fh_tree;
nh.null_next = pd[0];
nh.null_len = pd[1];
memcpy((char *)&nh.null_family, (char *)&pd[2], sizeof(nh.null_family));
/* load the top pane info. This should be overwritten by
the next protocol in the stack */
if(fd->win_info[COL_NUM]) {
strcpy(fd->win_info[COL_SOURCE], "N/A" );
strcpy(fd->win_info[COL_DESTINATION], "N/A" );
strcpy(fd->win_info[COL_PROTOCOL], "N/A" );
strcpy(fd->win_info[COL_INFO], "Null/Loopback" );
}
/* populate a tree in the second pane with the status of the link
layer (ie none) */
if(tree) {
ti = add_item_to_tree( GTK_WIDGET(tree), 0, 4,
"Null/Loopback (%d on link, %d captured)", fd->pkt_len,
fd->cap_len );
fh_tree = gtk_tree_new();
add_subtree(ti, fh_tree, ETT_NULL);
add_item_to_tree(fh_tree, 0, 1, "Next: %02x", nh.null_next);
add_item_to_tree(fh_tree, 1, 1, "Length: %02x", nh.null_len);
add_item_to_tree(fh_tree, 2, 2, "Family: %04x", nh.null_family);
}
/*
From what I've read in various sources, this is supposed to be an
address family, e.g. AF_INET. However, a FreeBSD ISDN PPP dump that
Andreas Klemm sent to ethereal-dev has a packet type of DLT_NULL, and
the family bits look like PPP's protocol field. A dump of the loopback
interface on my Linux box also has a link type of DLT_NULL (as it should
be), but the family bits look like ethernet's protocol type. To
further confuse matters, nobody seems to be paying attention to byte
order.
- gcc
*/
switch (nh.null_family) {
case 0x0008:
case 0x0800:
case 0x0021:
case 0x2100:
dissect_ip(pd, 4, fd, tree);
break;
default:
dissect_data(pd, 4, fd, tree);
break;
}
}
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