["Bingyao Du" <dubingyao@xxxxxxxxx>]

Hi Amit

My problem is there are too many fields in only one protocol. So, I want to split the packet into two independent dissectors. I attached it:) 


Steve,

I do it as you said. But the problem is there are too many fields. I think it's better split it into two protocols. Attached the C file. The problem troubles me for many days. Wow...

Best regards

-Bingyao

2007/1/27, Stephen Fisher <stephentfisher@xxxxxxxxx>:

On Sat, Jan 27, 2007 at 01:06:19AM +0800, Bingyao Du wrote:

> The protocol I'm dissecting has a "header" portion, that contains a
> "type field", and then a payload with different format for each type.
> The Header protion contains several fields.
>
> I thinks it's better to display the packet with two dissectors, just
> looks like IP dissector and TCP dissector. What should I do? Or could
> you send me an example or demo? Thanks very much.

The best/easiest way to do it is within the same dissector.  A dissector
you can use as an example is packet-wlccp.c.  The only difference is
that the version (akin to your type) field is at the beginning of the
packet, but that doesn't make a difference in how it's implemented.
Line 205 gets the version (type in your case) and line 208 checks if the
type is 0x0 and displays fields based on that version.  Line 231 checks
if the version is instead 0xC1 and displays fields based on that
version.


Steve

/* packet-nsrp.c
 * Routines for the Juniper Netscreen Redundant Protocol (NSRP)
 *
 * Bingyao Du <dubingyao@xxxxxxxxx>
 *
 * $Id$
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@xxxxxxxxxxxxx>
 * Copyright 1998 Gerald Combs
 *
 *
 * 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.
 */

/* 
 *
 * NSRP update information can be found at www.juniper.net
 *
 *
 *           
 *    NSRP Packet Header is defined as follow:
 *                  
 *       1         2       3        4        5         6       7        8 
 *   +--------+--------+--------+--------+--------+--------+--------+--------+
 *   |Version | Type   |Clust ID|MSG Flag|     Length      |HA Port |Not Used|
 *   +--------+--------+--------+--------+--------+--------+--------+--------+
 *   |          Destination Unit         |             Source Unit           |
 *   +--------+--------+--------+--------+--------+--------+--------+--------+
 *
 *
 *
 */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <glib.h>

#include <epan/packet.h>

#define ETHER_TYPE_NSRP 0x8133
#define NSRP_MIN_LEN    32

/* Initialize the protocol and registered fields */
static int proto_nsrp       = -1;

static int hf_nsrp_version       = -1;
static int hf_nsrp_msg_type      = -1;
static int hf_nsrp_clust_id      = -1;
static int hf_nsrp_msg_flag      = -1;
static int hf_nsrp_len           = -1;
static int hf_nsrp_ha_port       = -1;
static int hf_nsrp_not_used      = -1;
static int hf_nsrp_dst_unit      = -1;
static int hf_nsrp_src_unit      = -1;
static int hf_nsrp_msgtype       = -1;
static int hf_nsrp_wst_group     = -1;
static int hf_nsrp_hst_group     = -1;
static int hf_nsrp_msgflag     = -1;
static int hf_nsrp_authflag      = -1;
static int hf_nsrp_priority      = -1;
static int hf_nsrp_dummy         = -1;
static int hf_nsrp_authchecksum  = -1;
static int hf_nsrp_ifnum         = -1;


/* Dada defined for HA Message */
static int hf_nsrp_msglen      = -1;
static int hf_nsrp_encflag      = -1;
static int hf_nsrp_notused = -1;

static int hf_nsrp_total_size = -1;

static int hf_nsrp_ns = -1;
static int hf_nsrp_nr = -1;

static int hf_nsrp_no_used = -1;
static int hf_nsrp_checksum = -1;

static int hf_nsrp_data = -1;


static const value_string nsrp_msg_type_vals[] = {
	{ 0x01,	"HA MESSAGE" },
	{ 0x02,	"MNG MESSAGE" },
	{ 0x03,	"DADA MESSAGE" },
	{ 0,			NULL }
};

static const value_string nsrp_msgtype_vals[] = {
	{ 0x01,	"CREATE SESSION" },
	{ 0x02,	"CLOSE SESSION" },
	{ 0x03,	"CHANG SESSION" },
	{ 0x04,	"CREATE SP SESSION" },
	{ 0x05,	"SYS CONFIG" },
	{ 0x06,	"FILE SYS" },
	{ 0x07,	"CMD WEB" },
	{ 0x08,	"SAVE SLAVE" },
	{ 0x09,	"VPN SPI" },
	{ 0x0a,	"ARP" },
	{ 0x0b,	"HEALTH CHECK" },
	{ 0x0c,	"EMW DATA" },
	{ 0x0d,	"INVITE SYNC" },
	{ 0x0e,	"DOWNLOAD CONFIG" },
	{ 0x0f,	"L2TP TUNL CREATE" },
	{ 0x10,	"L2TP TUNL DELETE" },
	{ 0x11,	"L2TP CALL CREATE" },
	{ 0x12,	"L2TP CALL DELETE" },
	{ 0x13,	"PKI SYNC" },
	{ 0x14,	"VPN SEQ" },
	{ 0x15,	"MAX" },
	{ 0,			NULL }
};

static const value_string nsrp_flag_vals[] = {
	{ 0x80,	"ENCRPT MESSAGE" },
	{ 0x40,	"CLOSE SESSION" },
	{ 0x20,	"CHANG SESSION" },
	{ 0x10,	"CREATE SP SESSION" },
	{ 0x08,	"SYS CONFIG" },
	{ 0x04,	"FILE SYS" },
	{ 0x02,	"CMD WEB" },
	{ 0,			NULL }
};

static const value_string nsrp_encflag_vals[] = {
	{ 0xf0,	"ENCRYPT METHOD MASK" },
	{ 0x0f,	"ENCRYPT PAD BIT MASK" },
	{ 0,			NULL }
};


/* Initialize the subtree pointers */
static gint ett_nsrp = -1;

/* Code to actually dissect the packets */
static void
dissect_nsrp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
    proto_item  *ti;
    proto_tree  *nsrp_tree = NULL;
    gint        offset = 0;
    guint8      msgtype = 0;

    if (check_col(pinfo->cinfo, COL_PROTOCOL))
			col_set_str(pinfo->cinfo, COL_PROTOCOL, "NSRP");

    if (check_col(pinfo->cinfo, COL_INFO))
    {
			col_clear(pinfo->cinfo, COL_INFO);
			col_set_str(pinfo->cinfo, COL_INFO, "NSRP Protocol");
		}

    if (tree) {
			ti = proto_tree_add_item(tree, proto_nsrp, tvb, 0, -1, FALSE);
			nsrp_tree = proto_item_add_subtree(ti, ett_nsrp);
			
			
			proto_tree_add_item(nsrp_tree, hf_nsrp_version, tvb, offset, 1, FALSE);
			offset += 1;

			msgtype = tvb_get_guint8(tvb, offset);
			proto_tree_add_item(nsrp_tree, hf_nsrp_msg_type, tvb, offset, 1, FALSE);
			offset += 1;
		
			proto_tree_add_item(nsrp_tree, hf_nsrp_clust_id, tvb, offset, 1, FALSE);
			offset += 1;
			
			proto_tree_add_item(nsrp_tree, hf_nsrp_msg_flag, tvb, offset, 1, FALSE);
			offset += 1;

			proto_tree_add_item(nsrp_tree, hf_nsrp_len, tvb, offset, 2, FALSE);
			offset += 2;
		
			proto_tree_add_item(nsrp_tree, hf_nsrp_ha_port, tvb, offset, 1, FALSE);
			offset += 1;
			
			proto_tree_add_item(nsrp_tree, hf_nsrp_not_used, tvb, offset, 1, FALSE);
			offset += 1;

			proto_tree_add_item(nsrp_tree, hf_nsrp_dst_unit, tvb, offset, 4, FALSE);
			offset += 4;

			proto_tree_add_item(nsrp_tree, hf_nsrp_src_unit, tvb, offset, 4, FALSE);
			offset += 4;
		}
		
/*
 *
 *
 *    NSRP HA Packet is defined as follow:
 * 
 *       1         2       3        4        5         6       7        8 
 *   +--------+--------+--------+--------+--------+--------+--------+--------+
 *   | Type   |WstGroup|HstGroup|MSG Flag|     Length      |Enc Flag|Not Used|
 *   +--------+--------+--------+--------+--------+--------+--------+--------+
 *   |            Total Size             |        NS       |        NR       |
 *   +--------+--------+--------+--------+--------+--------+--------+--------+
 *   |     No Used     |    Checksum     |              Data                 |
 *   +--------+--------+--------+--------+-----------------------------------+
 *
 *
 */

		if ( msgtype == 0x00 ) {
			
			proto_tree_add_item(nsrp_tree, hf_nsrp_msgtype, tvb, offset, 1, FALSE);
			offset += 1;

			proto_tree_add_item(nsrp_tree, hf_nsrp_wst_group, tvb, offset, 1, FALSE);
			offset += 1;

			proto_tree_add_item(nsrp_tree, hf_nsrp_hst_group, tvb, offset, 1, FALSE);
			offset += 1;

			proto_tree_add_item(nsrp_tree, hf_nsrp_msgflag, tvb, offset, 1, FALSE);
			offset += 1;
		
			proto_tree_add_item(nsrp_tree, hf_nsrp_msglen, tvb, offset, 2, FALSE);
			offset += 2;
			
			proto_tree_add_item(nsrp_tree, hf_nsrp_encflag, tvb, offset, 1, FALSE);
			offset += 1;

			proto_tree_add_item(nsrp_tree, hf_nsrp_not_used, tvb, offset, 1, FALSE);
			offset += 1;

			proto_tree_add_item(nsrp_tree, hf_nsrp_total_size, tvb, offset, 4, FALSE);
			offset += 4;
		
			proto_tree_add_item(nsrp_tree, hf_nsrp_ns, tvb, offset, 2, FALSE);
			offset += 2;
			
			proto_tree_add_item(nsrp_tree, hf_nsrp_nr, tvb, offset, 2, FALSE);
			offset += 2;

			proto_tree_add_item(nsrp_tree, hf_nsrp_no_used, tvb, offset, 2, FALSE);
			offset += 2;
		
			proto_tree_add_item(nsrp_tree, hf_nsrp_checksum, tvb, offset, 2, FALSE);
			offset += 2;
			
			proto_tree_add_item(nsrp_tree, hf_nsrp_data, tvb, offset, -1, FALSE);
			
    }
    
/*
 *  
 *    NSRP MNG Packet is defined as follow:
 * 
 *       1         2       3        4        5         6       7        8 
 *   +--------+--------+--------+--------+--------+--------+--------+--------+
 *   | Type   |WstGroup|HstGroup|MSG Flag|     Length      |AuthFlag|Not Used|
 *   +--------+--------+--------+--------+--------+--------+--------+--------+
 *   |Priority+ Dummy  +   Auth CheckSum +                Data               |
 *   +--------+--------+--------+--------+-----------------------------------+
 *  
 *
 */

		if ( msgtype == 0x02 ) {
			
			proto_tree_add_item(nsrp_tree, hf_nsrp_msgtype, tvb, offset, 1, FALSE);
			offset += 1;

			proto_tree_add_item(nsrp_tree, hf_nsrp_wst_group, tvb, offset, 1, FALSE);
			offset += 1;

			proto_tree_add_item(nsrp_tree, hf_nsrp_hst_group, tvb, offset, 1, FALSE);
			offset += 1;

			proto_tree_add_item(nsrp_tree, hf_nsrp_msgflag, tvb, offset, 1, FALSE);
			offset += 1;
		
			proto_tree_add_item(nsrp_tree, hf_nsrp_msglen, tvb, offset, 2, FALSE);
			offset += 2;
			
			proto_tree_add_item(nsrp_tree, hf_nsrp_authflag, tvb, offset, 1, FALSE);
			offset += 1;

			proto_tree_add_item(nsrp_tree, hf_nsrp_not_used, tvb, offset, 1, FALSE);
			offset += 1;

			proto_tree_add_item(nsrp_tree, hf_nsrp_priority, tvb, offset, 1, FALSE);
			offset += 1;
		
			proto_tree_add_item(nsrp_tree, hf_nsrp_dummy, tvb, offset, 1, FALSE);
			offset += 1;
			
			proto_tree_add_item(nsrp_tree, hf_nsrp_authchecksum, tvb, offset, 2, FALSE);
			offset += 2;

			proto_tree_add_item(nsrp_tree, hf_nsrp_data, tvb, offset, -1, FALSE);
			
    }
    
        
    
    
/*   
 *    NSRP DATA Packet is defined as follow:
 * 
 *       1         2       3        4        5         6       7        8 
 *   +--------+--------+--------+--------+--------+--------+--------+--------+
 *   | Type   |WstGroup|HstGroup|MSG Flag|     Length      | Ifnum  |Not Used|
 *   +--------+--------+--------+--------+--------+--------+--------+--------+
 *   |            Total Size             |                Data               |
 *   +--------+--------+--------+--------+-----------------------------------+
 *
 *
 */
   if ( msgtype == 0x03 ) {
			
			proto_tree_add_item(nsrp_tree, hf_nsrp_msgtype, tvb, offset, 1, FALSE);
			offset += 1;

			proto_tree_add_item(nsrp_tree, hf_nsrp_wst_group, tvb, offset, 1, FALSE);
			offset += 1;

			proto_tree_add_item(nsrp_tree, hf_nsrp_hst_group, tvb, offset, 1, FALSE);
			offset += 1;

			proto_tree_add_item(nsrp_tree, hf_nsrp_msgflag, tvb, offset, 1, FALSE);
			offset += 1;
		
			proto_tree_add_item(nsrp_tree, hf_nsrp_msglen, tvb, offset, 2, FALSE);
			offset += 2;
			
			proto_tree_add_item(nsrp_tree, hf_nsrp_ifnum, tvb, offset, 1, FALSE);
			offset += 1;

			proto_tree_add_item(nsrp_tree, hf_nsrp_not_used, tvb, offset, 1, FALSE);
			offset += 1;

			proto_tree_add_item(nsrp_tree, hf_nsrp_total_size, tvb, offset, 4, FALSE);
			offset += 4;
		
			proto_tree_add_item(nsrp_tree, hf_nsrp_data, tvb, offset, -1, FALSE);
			
    }

}


void
proto_register_nsrp(void)
{

    static hf_register_info hf[] = {
	{ &hf_nsrp_version,
	  { "Version", "nsrp.version",
	    FT_UINT8, BASE_DEC, NULL, 0,
	    "NSRP Version", HFILL }
	},
		{ &hf_nsrp_msg_type,
	  { "Type", "nsrp.type",
	    FT_UINT8, BASE_DEC, nsrp_msg_type_vals, 0,
	    "NSRP Message Type", HFILL }
	},
		{ &hf_nsrp_clust_id,
	  { "Clust ID", "nsrp.clustid",
	    FT_UINT8, BASE_DEC, NULL, 0,
	    "NSRP CLUST ID", HFILL }
	},
		{ &hf_nsrp_msg_flag,
	  { "Flag", "nsrp.flag",
	    FT_UINT8, BASE_DEC, NULL, 0,
	    "NSRP FLAG", HFILL }
	},
	{ &hf_nsrp_len,
	  { "Length", "nsrp.length",
	    FT_UINT16, BASE_DEC, NULL, 0,
	    "NSRP Length", HFILL }
	},
		{ &hf_nsrp_ha_port,
	  { "Port", "nsrp.haport",
	    FT_UINT8, BASE_DEC, NULL, 0,
	    "NSRP HA Port", HFILL }
	},
		{ &hf_nsrp_not_used,
	  { "Not used", "nsrp.notused",
	    FT_UINT8, BASE_DEC, NULL, 0,
	    "NOT USED", HFILL }
	},
		{ &hf_nsrp_dst_unit,
	  { "Destination", "nsrp.dst",
	    FT_UINT32, BASE_DEC, NULL, 0,
	    "DESTINATION UNIT INFORMATION", HFILL }
	},
	{ &hf_nsrp_src_unit,
	  { "Source", "nsrp.src",
	    FT_UINT32, BASE_DEC, NULL, 0,
	    "SOURCE UNIT INFORMATION", HFILL }
	},
		{ &hf_nsrp_msgtype,
	  { "MsgType", "nsrp.msgtype",
	    FT_UINT8, BASE_DEC, VALS(nsrp_msgtype_vals), 0,
	    "Message Type", HFILL }
	},
		{ &hf_nsrp_wst_group,
	  { "Wst group", "nsrp.wst",
	    FT_UINT8, BASE_DEC, NULL, 0,
	    "NSRP WST GROUP", HFILL }
	},
		{ &hf_nsrp_hst_group,
	  { "Hst group", "nsrp.hst",
	    FT_UINT8, BASE_DEC, NULL, 0,
	    "NSRP HST GROUP", HFILL }
	},
	{ &hf_nsrp_msgflag,
	  { "Msgflag", "nsrp.msgflag",
	    FT_UINT8, BASE_DEC, VALS(nsrp_flag_vals), 0,
	    "NSRP MSG FLAG", HFILL }
	},
	{ &hf_nsrp_msglen,
	  { "Msg Length", "nsrp.msglen",
	    FT_UINT16, BASE_DEC, NULL, 0,
	    "NSRP MESSAGE LENGTH", HFILL }
	},
		
	{ &hf_nsrp_encflag,
	  { "Enc Flag", "nsrp.encflag",
	    FT_UINT8, BASE_DEC, VALS(nsrp_encflag_vals), 0,
	    "NSRP ENCRYPT FLAG", HFILL }
	},
		{ &hf_nsrp_notused,
	  { "Not Used", "nsrp.notused",
	    FT_UINT8, BASE_DEC, NULL, 0,
	    "NOT USED", HFILL }
	},
		{ &hf_nsrp_total_size,
	  { "Total Size", "nsrp.totalsize",
	    FT_UINT32, BASE_DEC, NULL, 0,
	    "NSRP MSG TOTAL MESSAGE", HFILL }
	},
		{ &hf_nsrp_ns,
	  { "Ns", "nsrp.ns",
	    FT_UINT16, BASE_DEC, NULL, 0,
	    "Ns", HFILL }
	},
		{ &hf_nsrp_nr,
	  { "Nr", "nsrp.nr",
	    FT_UINT16, BASE_DEC, NULL, 0,
	    "Nr", HFILL }
	},
		{ &hf_nsrp_no_used,
	  { "Reserved", "nsrp.reserved",
	    FT_UINT16, BASE_DEC, NULL, 0,
	    "RESERVED", HFILL }
	},
		{ &hf_nsrp_checksum,
	  { "Checksum", "nsrp.checksum",
	    FT_UINT16, BASE_HEX, NULL, 0,
	    "NSRP PACKET CHECKSUM", HFILL }
	},
		{ &hf_nsrp_authflag,
	  { "AuthFlag", "nsrp.authflag",
	    FT_UINT8, BASE_HEX, NULL, 0,
	    "NSRP Auth Flag", HFILL }
	},
			{ &hf_nsrp_priority,
	  { "Priority", "nsrp.priority",
	    FT_UINT8, BASE_HEX, NULL, 0,
	    "NSRP Priority", HFILL }
	},
			{ &hf_nsrp_dummy,
	  { "Dummy", "nsrp.dummy",
	    FT_UINT8, BASE_HEX, NULL, 0,
	    "NSRP Dummy", HFILL }
	},
		{ &hf_nsrp_authchecksum,
	  { "Checksum", "nsrp.authchecksum",
	    FT_UINT16, BASE_HEX, NULL, 0,
	    "NSRP AUTH CHECKSUM", HFILL }
	},
		{ &hf_nsrp_ifnum,
	  { "Ifnum", "nsrp.ifnum",
	    FT_UINT16, BASE_HEX, NULL, 0,
	    "NSRP IfNum", HFILL }
	},
	{ &hf_nsrp_data,
	  { "Data", "nsrp.data",
	    FT_STRING, 0, NULL, 0,
	    "PADING", HFILL }
	}
    };

    static gint *ett[] = {
	&ett_nsrp,
    };

    proto_nsrp = proto_register_protocol("Juniper Netscreen Redundant Protocol",
	"NSRP", "nsrp");
    proto_register_field_array(proto_nsrp, hf, array_length(hf));
    proto_register_subtree_array(ett, array_length(ett));
}


void
proto_reg_handoff_nsrp(void)
{
    dissector_handle_t nsrp_handle;

    nsrp_handle = create_dissector_handle(dissect_nsrp, proto_nsrp);
    dissector_add("ethertype", ETHER_TYPE_NSRP, nsrp_handle);
}