Wireshark · Ethereal-dev: [Ethereal-dev] Rudimentary MS NLB plugin

[Jaap Keuter <jaap.keuter@xxxxxxxxx>]

Hi list,

I've created a rudimentary Microsoft Network Load Balancing protocol
dissector. From what I could recognize on a network, I derived some
fields, but it remains largly unknown. It's in the form of a plugin,
since it is no where in shape of being a full blown dissector.

These files need to go into your development tree ethereal/plugins/msnlb/
and the various additions described in README.plugin for the inclusion
of a plugin need to be executed.

If we think this is valuable enough, feel free to add it to the
repository.

Thanx,
Jaap

/* packet-msnlb.c
 * Routines for MS NLB dissection
 *
 * $Id:$
 *
 * Ethereal - Network traffic analyzer
 * By Gerald Combs <gerald@xxxxxxxxxxxx>
 * 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.
 */

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

#include "moduleinfo.h"

#include <gmodule.h>
#include <epan/packet.h>
#include <epan/proto.h>
#ifndef ENABLE_STATIC
#include <epan/emem.h>
#else
#include <epan/dissectors/packet-smb-common.h>
#endif
#include <epan/etypes.h>

#ifndef ENABLE_STATIC
G_MODULE_EXPORT gchar version[] = VERSION;
#endif

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

static int hf_msnlb_unknown = -1;
static int hf_msnlb_cls_virt_ip = -1;
static int hf_msnlb_host_ip = -1;
static int hf_msnlb_host_name = -1;

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

/* Get the unicode support in from packet-smb-common.c */
#ifndef ENABLE_STATIC
int display_unicode_string(tvbuff_t *tvb, proto_tree *tree, int offset, int hf_index, char **data)
{
	char *str, *p;
	int len;
	int charoffset;
	guint16 character;

	/* display a unicode string from the tree and return new offset */

	/*
	 * Get the length of the string.
	 * XXX - is it a bug or a feature that this will throw an exception
	 * if we don't find the '\0'?  I think it's a feature.
	 */
	len = 0;
	while ((character = tvb_get_letohs(tvb, offset + len)) != '\0')
		len += 2;
	len += 2;	/* count the '\0' too */

	/*
	 * Allocate a buffer for the string; "len" is the length in
	 * bytes, not the length in characters.
	 */
	str = ep_alloc(len/2);

	/*
	 * XXX - this assumes the string is just ISO 8859-1; we need
	 * to better handle multiple character sets in Ethereal,
	 * including Unicode/ISO 10646, and multiple encodings of
	 * that character set (UCS-2, UTF-8, etc.).
	 */
	charoffset = offset;
	p = str;
	while ((character = tvb_get_letohs(tvb, charoffset)) != '\0') {
		*p++ = (char) character;
		charoffset += 2;
	}
	*p = '\0';

	proto_tree_add_string(tree, hf_index, tvb, offset, len, str);

	if (data)
		*data = str;

	return 	offset+len;
}
#endif

/* Code to actually dissect the packets */
static void
dissect_msnlb(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
  proto_item  *ti;
  proto_tree  *msnlb_tree;
  guint16     offset = 0;

  guint8 type = 0; /* Blatent assumption of name and size */

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

  if (check_col(pinfo->cinfo, COL_INFO)) {
    col_clear(pinfo->cinfo, COL_INFO);
    col_append_fstr(pinfo->cinfo, COL_INFO, "MS NLB heartbeat");
  }

  if (tree) {
    ti = proto_tree_add_item(tree, proto_msnlb, tvb, 0, -1, FALSE);
    msnlb_tree = proto_item_add_subtree(ti, ett_msnlb);

    type = tvb_get_guint8(tvb, offset);

    proto_tree_add_item(msnlb_tree, hf_msnlb_unknown, tvb, offset, 4, FALSE);
    offset += 4;

    proto_tree_add_item(msnlb_tree, hf_msnlb_unknown, tvb, offset, 4, FALSE);
    offset += 4;

    proto_tree_add_item(msnlb_tree, hf_msnlb_unknown, tvb, offset, 4, FALSE);
    offset += 4;

    proto_tree_add_item(msnlb_tree, hf_msnlb_cls_virt_ip, tvb, offset, 4, FALSE);
    offset += 4;

    proto_tree_add_item(msnlb_tree, hf_msnlb_host_ip, tvb, offset, 4, FALSE);
    offset += 4;

    proto_tree_add_item(msnlb_tree, hf_msnlb_unknown, tvb, offset, 4, FALSE);
    offset += 4;

    proto_tree_add_item(msnlb_tree, hf_msnlb_unknown, tvb, offset, 4, FALSE);
    offset += 4;

    switch (type) {
      case 0xc0:
        offset = display_unicode_string(tvb, msnlb_tree, offset, hf_msnlb_host_name, NULL);
        break;

      case 0xbf:
        proto_tree_add_item(msnlb_tree, hf_msnlb_unknown, tvb, offset, 4, FALSE);
        offset += 4;

        proto_tree_add_item(msnlb_tree, hf_msnlb_unknown, tvb, offset, 4, FALSE);
        offset += 4;

        proto_tree_add_item(msnlb_tree, hf_msnlb_unknown, tvb, offset, 4, FALSE);
        offset += 4;

        proto_tree_add_item(msnlb_tree, hf_msnlb_unknown, tvb, offset, 4, FALSE);
        offset += 4;

        proto_tree_add_item(msnlb_tree, hf_msnlb_unknown, tvb, offset, 4, FALSE);
        offset += 4;

        proto_tree_add_item(msnlb_tree, hf_msnlb_unknown, tvb, offset, 4, FALSE);
        offset += 4;

        proto_tree_add_item(msnlb_tree, hf_msnlb_unknown, tvb, offset, 4, FALSE);
        offset += 4;

        proto_tree_add_item(msnlb_tree, hf_msnlb_unknown, tvb, offset, 4, FALSE);
        offset += 4;

        proto_tree_add_item(msnlb_tree, hf_msnlb_unknown, tvb, offset, 4, FALSE);
        offset += 4;

        proto_tree_add_item(msnlb_tree, hf_msnlb_unknown, tvb, offset, 4, FALSE);
        offset += 4;

      default:
        proto_tree_add_item(msnlb_tree, hf_msnlb_unknown, tvb, offset, tvb_length_remaining(tvb, offset), FALSE);
        offset += 4;
    }
  }
}

void
proto_register_msnlb(void)
{
  static hf_register_info hf[] = {
    { &hf_msnlb_unknown,
      { "Unknown", "msnlb.unknown",
        FT_BYTES, BASE_HEX, NULL, 0,
        "", HFILL }
    },
    { &hf_msnlb_host_ip,
      { "Host IP", "msnlb.host_ip",
        FT_IPv4, BASE_HEX, NULL, 0,
        "Host IP address", HFILL }
    },
    { &hf_msnlb_cls_virt_ip,
      { "Cluster Virtual IP", "msnlb.cluster_virtual_ip",
        FT_IPv4, BASE_HEX, NULL, 0,
        "Cluster Virtual IP address", HFILL }
    },
    { &hf_msnlb_host_name,
      { "Host name", "msnlb.host_name",
        FT_STRING, BASE_NONE, NULL, 0,
        "Host name", HFILL }
    }
  };

  static gint *ett[] = {
    &ett_msnlb
  };

  proto_msnlb = proto_register_protocol("MS NLB", "msnlb", "msnlb");
  proto_register_field_array(proto_msnlb, hf, array_length(hf));
  proto_register_subtree_array(ett, array_length(ett));
}

void
proto_reg_handoff_msnlb(void)
{
  dissector_handle_t msnlb_handle;

  msnlb_handle = create_dissector_handle(dissect_msnlb, proto_msnlb);
  dissector_add("ethertype", ETHERTYPE_MS_NLB_HEARTBEAT, msnlb_handle);
}

/* Start the functions we need for the plugin stuff */

/*
 * Function which has to be exported
 */
#ifndef ENABLE_STATIC
G_MODULE_EXPORT void
plugin_reg_handoff(void)
{
  proto_reg_handoff_msnlb();
}
#endif 

/*
 * The initialization procedure
 */
#ifndef ENABLE_STATIC
G_MODULE_EXPORT void
plugin_register(void)
{
  /* execute protocol initialization only once */
  if (proto_msnlb == -1) 
  { 
    /* register the new protocol, protocol fields, and subtrees */
    proto_register_msnlb();
  }
}
#endif

/* End the functions we need for plugin stuff */

/* Included *after* config.h, in order to re-define these macros */

#ifdef PACKAGE
#undef PACKAGE
#endif

/* Name of package */
#define PACKAGE "msnlb"


#ifdef VERSION
#undef VERSION
#endif

/* Version number of package */
#define VERSION "0.0.1"

# Makefile.am
# Automake file for Ethereal/MS NLB
#
# $Id:$
#
# Ethereal - Network traffic analyzer
# By Gerald Combs <gerald@xxxxxxxxxxxx>
# 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.
#

INCLUDES = -I$(top_srcdir)

plugindir = @plugindir@

plugin_LTLIBRARIES = msnlb.la
msnlb_la_SOURCES = packet-msnlb.c moduleinfo.h
msnlb_la_LDFLAGS = -module -avoid-version
msnlb_la_LIBADD = @PLUGIN_LIBS@

# Libs must be cleared, or else libtool won't create a shared module.
# If your module needs to be linked against any particular libraries,
# add them here.
LIBS =

CLEANFILES = \
	msnlb \
	*~

MAINTAINERCLEANFILES = \
	Makefile.in

EXTRA_DIST = \
	Makefile.nmake

#
# $Id:$
#

include ..\..\config.nmake

############### no need to modify below this line #########

CFLAGS=/DHAVE_CONFIG_H /I../.. /I../../wiretap $(GLIB_CFLAGS) \
	/I$(PCAP_DIR)\include -D_U_="" $(LOCAL_CFLAGS)

LDFLAGS = /NOLOGO /INCREMENTAL:no /MACHINE:I386 $(LOCAL_LDFLAGS)

!IFDEF ENABLE_LIBETHEREAL
LINK_PLUGIN_WITH=..\..\epan\libethereal.lib
CFLAGS=/DHAVE_WIN32_LIBETHEREAL_LIB /D_NEED_VAR_IMPORT_ $(CFLAGS)

OBJECTS=packet-msnlb.obj 

msnlb.dll msnlb.exp msnlb.lib : $(OBJECTS) $(LINK_PLUGIN_WITH)
	link -dll /out:msnlb.dll $(LDFLAGS) $(OBJECTS) $(LINK_PLUGIN_WITH) \
	$(GLIB_LIBS)

!ENDIF

clean:
	rm -f $(OBJECTS) msnlb.dll msnlb.exp msnlb.lib *.pdb

distclean: clean

maintainer-clean: distclean