Updated the frame relay dissector - dissect-fr.c

Added the LMI dissector for frame relay - dissect-lmi.c
Added Wellfleet compression dissector - dissect-wcp.c

svn path=/trunk/; revision=3168

1 files changed, 756 insertions, 0 deletions

diff --git a/packet-wcp.c b/packet-wcp.c
new file mode 100644
index 0000000000..9665cfea1f
--- /dev/null
+++ b/packet-wcp.c
@@ -0,0 +1,756 @@
+/* packet-wcp.c
+ * Routines for Wellfleet Compression frame disassembly
+ * Copyright 2001, Jeffrey C. Foster <jfoste@woodward.com>
+ *
+ * $Id: packet-wcp.c,v 1.1 2001/03/23 19:22:02 jfoster Exp $
+ *
+ * Ethereal - Network traffic analyzer
+ * By Gerald Combs <gerald@zing.org>
+ * 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.
+ *
+ * ToDo:
+ *	Add preference to allow/disallow decompression
+ *	Calculate and verify check byte (last byte), if only we knew how!
+ *	Handle Wellfleet compression over PPP links.
+ *		- This will require changing the sub-dissector call
+ *		  routine to determine if layer 2 is frame relay or
+ *		  or PPP and different sub-dissector routines for each.
+ *
+ * Based upon information in the Nortel TCL based Pcaptap code.
+ *http://www.mynetworkforum.com/tools/PCAPTAP/pcaptap-Win32-3.00.exe
+ *
+ * And lzss algorithm
+ *http://www.rasip.fer.hr/research/compress/algorithms/fund/lz/lzss.html
+ */
+
+/*
+ * Wellfleet compression is a variation on LZSS encoding.
+ *
+ * Compression is done by keeping a sliding window of previous 
+ * data transmited. The sender will use a pattern match to 
+ * encode repeated data as a data pointer field. Then a stream
+ * of pointers and actual data bytes. The pointer values include
+ * an offset to previous data in the stream and the length of the
+ *  matching data.
+ *
+ * The data pattern matching is done on the octects. 
+ *
+ * The data is encoded as 8 field blocks with a compression flag
+ * byte at the beginning.  If the bit is set in the compression
+ * flag, then that field has a compression field. If it isn't set
+ * then the byte is raw data.
+ *
+ * The compression field is either 2 or 3 bytes long. The length
+ * is determined by the length of the matching data, for short
+ * matches the match length is encoded in the high nibble of the
+ * first byte. Otherwise the third byte of the field contains 
+ * the match length.
+ *
+ * First byte -
+ * lower 4 bits:
+ *		High order nibble of the offset
+ *
+ * upper 4 bits:
+ *		1   = length is in 3rd byte 
+ *		2-F = length of matching data - 1
+ *		
+ * Second byte - 
+ *  Lower byte of the source offset.
+ *
+ * Third byte - 
+ *  Length of match - 1 if First byte upper nibble = 1, otherwise
+ *  this byte isn't added to data stream.
+ *
+ * Example:
+ * 	Uncompressed data (hex):  11 22 22 22 22 33 44 55 66 77
+ *
+ *
+ *	Compression data :
+ *			Flag bits:	0x20 (third field is compressed)
+ *			Data:	11 22 20 00 33 44 55
+ *				/  /  /  /
+ *		raw data ------+--+  /	/	 	
+ *              (Comp length - 1)<<4+  /
+ *		Data offset ----------+
+ *
+ *	Output data (hex):  20 11 22 20 00 33 44 55 66 77
+ *
+ * In this example the copy src is one byte behind the copy destination
+ * so if appears as if output is being loaded with the source byte.
+ *
+ */
+
+
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#ifdef HAVE_SYS_TYPES_H
+# include <sys/types.h>
+#endif
+
+#include <stdio.h>
+#include <glib.h>
+#include <string.h>
+#include "packet.h"
+#include "packet-frame.h"
+#include "packet-osi.h"
+#include "conversation.h"
+#include "nlpid.h"
+#include "oui.h"
+#include "packet-llc.h"
+
+#define MAX_WIN_BUF_LEN 0x7fff		/* storage size for decompressed data */
+#define MAX_WCP_BUF_LEN 2048		/* storage size for decompressed data */
+#define FROM_DCE	0x80		/* for direction setting */
+
+typedef struct {
+
+	guint8  *buf_cur;
+ 	guint8  buffer[MAX_WIN_BUF_LEN];
+
+}wcp_window_t;
+
+/*XXX do I really want the length in here  */
+typedef struct {
+
+ 	guint16  len;
+ 	guint8  buffer[MAX_WCP_BUF_LEN];
+
+}wcp_pdata_t;
+
+
+#define wcp_win_init_count 4
+#define wcp_packet_init_count 10
+
+#define wcp_win_length (sizeof(wcp_window_t))
+#define wcp_packet_length (sizeof(wcp_pdata_t))
+
+static GMemChunk *wcp_window = NULL;
+static GMemChunk *wcp_pdata = NULL;
+
+extern dissector_table_t fr_subdissector_table;
+
+static int proto_wcp = -1;
+static int hf_wcp_cmd = -1;
+static int hf_wcp_ext_cmd = -1;
+static int hf_wcp_seq = -1;
+static int hf_wcp_chksum = -1;
+static int hf_wcp_tid = -1;
+static int hf_wcp_rev = -1;
+static int hf_wcp_init = -1;
+static int hf_wcp_seq_size = -1;
+static int hf_wcp_alg = -1;
+static int hf_wcp_alg_cnt = -1;
+static int hf_wcp_alg_a = -1;
+static int hf_wcp_alg_b = -1;
+static int hf_wcp_alg_c = -1;
+static int hf_wcp_alg_d = -1;
+static int hf_wcp_rexmit = -1;
+
+static int hf_wcp_hist_size = -1;
+static int hf_wcp_ppc = -1;
+static int hf_wcp_pib = -1;
+
+static int hf_wcp_comp_bits = -1;
+static int hf_wcp_comp_marker = -1;
+static int hf_wcp_short_len = -1;
+static int hf_wcp_long_len = -1;
+static int hf_wcp_short_run = -1;
+static int hf_wcp_long_run = -1;
+static int hf_wcp_offset = -1;
+
+/*$$ are these needed or should the Frame relay stuff be used (call a decoder in frame relay)?? */
+static int hf_wcp_oui = -1;
+static int hf_wcp_pid = -1;
+static int hf_wcp_type = -1;
+
+static gint ett_wcp = -1;
+static gint ett_wcp_field = -1;
+
+#define NLPID_WCP 0xb0			/* NLPID value for WCP */
+#define ETHERTYPE_WCP 0x80ff		/* ether snap value for WCP */
+
+/*
+ * Bits in the address field.
+ */
+#define	WCP_CMD			0xf0	/* WCP Command */
+#define	WCP_EXT_CMD		0x0f	/* WCP Extended Command */
+#define	WCP_SEQ			0x0fff	/* WCP Sequence number */
+#define	WCP_OFFSET_MASK		0x0fff	/* WCP Pattern source offset */
+
+#define PPC_COMPRESSED_IND       	0x0
+#define	PPC_UNCOMPRESSED_IND       	0x1
+#define	PPC_TPPC_COMPRESSED_IND		0x2
+#define	PPC_TPPC_UNCOMPRESSED_IND  	0x3
+#define CONNECT_REQ                	0x4
+#define	CONNECT_ACK                	0x5
+#define	CONNECT_NAK                	0x6
+#define	DISCONNECT_REQ           	0x7
+#define	DISCONNECT_ACK             	0x8
+#define	INIT_REQ                   	0x9
+#define	INIT_ACK                   	0xa
+#define	RESET_REQ                  	0xb
+#define	RESET_ACK                  	0xc
+#define	REXMIT_NAK                 	0xd
+
+
+static const value_string cmd_string[] = {
+	{0, "Compressed Data"},
+        {1, "Uncompressed Data"},
+        {15, "Extended"},
+	{ 0,       NULL }
+        };
+
+static const value_string ext_cmd_string[] = {
+	{0, "Per Packet Compression"},
+	{4, "Connect Req"},
+	{5, "Connect Ack"},
+	{9, "Init Req"},
+	{0x0a, "Init Ack"},
+
+	{ 0,       NULL }
+        };
+
+
+
+static tvbuff_t *wcp_uncompress( tvbuff_t *src_tvb, int offset, packet_info *pinfo, proto_tree *tree);
+static wcp_window_t *get_wcp_window_ptr( packet_info *pinfo);
+
+static void
+dissect_wcp_con_req(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree) {
+
+/* WCP connector request message */
+
+	guint alg_cnt = tvb_get_guint8(tvb, 5);
+
+	proto_tree_add_uint(tree, hf_wcp_tid, tvb, offset, 2, tvb_get_ntohs(tvb, offset));
+	proto_tree_add_uint(tree, hf_wcp_rev, tvb, offset + 2, 1, tvb_get_guint8(tvb, offset + 2));
+	proto_tree_add_uint(tree, hf_wcp_init, tvb, offset + 3, 1, tvb_get_guint8(tvb, offset + 3));
+	proto_tree_add_uint(tree, hf_wcp_seq_size, tvb, offset + 4, 1, tvb_get_guint8(tvb, offset + 4));
+	proto_tree_add_uint(tree, hf_wcp_alg_cnt, tvb, offset + 5, 1, alg_cnt);
+	proto_tree_add_uint(tree, hf_wcp_alg_a, tvb, offset + 6, 1, tvb_get_guint8(tvb, offset + 6));
+	if ( alg_cnt > 1)
+		proto_tree_add_uint(tree, hf_wcp_alg_b, tvb, offset + 7, 1, tvb_get_guint8(tvb, offset + 7));
+	if ( alg_cnt > 2)
+		proto_tree_add_uint(tree, hf_wcp_alg_c, tvb, offset + 8, 1, tvb_get_guint8(tvb, offset + 8));
+	if ( alg_cnt > 3)
+		proto_tree_add_uint(tree, hf_wcp_alg_d, tvb, offset + 9, 1, tvb_get_guint8(tvb, offset + 9));
+}
+
+static void
+dissect_wcp_con_ack( tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree){
+
+/* WCP connector ack message */
+
+	proto_tree_add_uint(tree, hf_wcp_tid, tvb, offset, 2, tvb_get_ntohs(tvb, offset));
+	proto_tree_add_uint(tree, hf_wcp_rev, tvb, offset + 2, 1, tvb_get_guint8(tvb, offset + 2));
+	proto_tree_add_uint(tree, hf_wcp_seq_size, tvb, offset + 3, 1, tvb_get_guint8(tvb, offset + 3));
+	proto_tree_add_uint(tree, hf_wcp_alg, tvb, offset + 4, 1, tvb_get_guint8(tvb, offset + 4));
+}
+
+static void
+dissect_wcp_init( tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree){
+
+/* WCP Initiate Request/Ack message */
+
+	proto_tree_add_uint(tree, hf_wcp_tid, tvb, offset, 2, tvb_get_ntohs(tvb, offset));
+	proto_tree_add_uint(tree, hf_wcp_rev, tvb, offset + 2, 1, tvb_get_guint8(tvb, offset + 2));
+	proto_tree_add_uint(tree, hf_wcp_hist_size, tvb, offset + 3, 1, tvb_get_guint8(tvb, offset + 3));
+	proto_tree_add_uint(tree, hf_wcp_ppc, tvb, offset + 4, 1, tvb_get_guint8(tvb, offset + 4));
+	proto_tree_add_uint(tree, hf_wcp_pib, tvb, offset + 5, 1, tvb_get_guint8(tvb, offset + 5));
+}
+
+
+static void
+dissect_wcp_reset( tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree){
+
+/* Process WCP Reset Request/Ack message */
+
+	proto_tree_add_uint(tree, hf_wcp_tid, tvb, offset, 2, tvb_get_ntohs(tvb, offset));
+}
+
+
+void wcp_save_data( tvbuff_t *tvb, packet_info *pinfo){
+
+	wcp_window_t *buf_ptr = 0;
+	int len; 
+
+	/* discard first 2 bytes, header and last byte (check byte) */
+	len = tvb_reported_length( tvb)-3;
+	buf_ptr = get_wcp_window_ptr( pinfo); 
+
+	if (( buf_ptr->buf_cur + len) <= (buf_ptr->buffer + MAX_WIN_BUF_LEN)){
+		tvb_memcpy( tvb, buf_ptr->buf_cur, 2, len);
+		buf_ptr->buf_cur = buf_ptr->buf_cur + len;
+	
+	} else {
+		guint8 *buf_end = buf_ptr->buffer + MAX_WIN_BUF_LEN; 
+		tvb_memcpy( tvb, buf_ptr->buf_cur, 2, buf_end - buf_ptr->buf_cur);
+		tvb_memcpy( tvb, buf_ptr->buffer, buf_end - buf_ptr->buf_cur-2,
+			len - (int)(buf_end - buf_ptr->buf_cur));
+		buf_ptr->buf_cur = buf_ptr->buf_cur + len - MAX_WIN_BUF_LEN;
+	}
+
+}
+
+
+void dissect_wcp( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
+
+	proto_tree	*wcp_tree;
+	proto_item	*ti;
+	int		wcp_header_len;
+	guint16		temp, cmd, ext_cmd, seq;
+	tvbuff_t	*next_tvb;
+	guint8		protocol_id;
+
+	temp = tvb_get_guint8(tvb, 0);
+
+        if (!proto_is_protocol_enabled(proto_wcp))
+                return;
+
+	temp =tvb_get_ntohs(tvb, 0); 
+	pinfo->current_proto = "WCP";
+
+	if (check_col(pinfo->fd, COL_PROTOCOL))
+		col_set_str(pinfo->fd, COL_PROTOCOL, "WCP");
+
+
+	cmd = (temp & 0xf000) >> 12;
+	ext_cmd = (temp & 0x0f00) >> 8;
+
+	if ( cmd == 0xf)
+		wcp_header_len= 1;
+	else 
+		wcp_header_len= 2;
+
+	seq = temp & 0x0fff;
+
+/*XXX should test seq to be sure it the last + 1 !! */
+
+	if (check_col(pinfo->fd, COL_INFO)){
+		col_add_str(pinfo->fd, COL_INFO, val_to_str(cmd, cmd_string, "Unknown"));
+		if ( cmd == 0xf)
+			col_append_fstr(pinfo->fd, COL_INFO, ", %s",
+				val_to_str(ext_cmd, ext_cmd_string, "Unknown"));
+	}	
+
+	if (tree) {
+		ti = proto_tree_add_item(tree, proto_wcp, tvb, 0, wcp_header_len, FALSE);
+
+		wcp_tree = proto_item_add_subtree(ti, ett_wcp);
+
+		proto_tree_add_uint(wcp_tree, hf_wcp_cmd, tvb, 0, 1, tvb_get_guint8( tvb, 0));
+		if ( cmd == 0xf){
+			proto_tree_add_uint(wcp_tree, hf_wcp_ext_cmd, tvb, 1, 1,
+					tvb_get_guint8( tvb, 0));
+			switch (ext_cmd){
+			case CONNECT_REQ:
+				dissect_wcp_con_req( tvb, 1, pinfo, wcp_tree);
+				break;
+
+			case CONNECT_ACK:
+				dissect_wcp_con_ack( tvb, 1, pinfo, wcp_tree);
+				break;
+			case INIT_REQ:
+			case INIT_ACK:
+				dissect_wcp_init( tvb, 1, pinfo, wcp_tree);
+				break;
+			case RESET_REQ:
+			case RESET_ACK:
+				dissect_wcp_reset( tvb, 1, pinfo, wcp_tree);
+				break;
+			default:
+				break;
+			}
+		}else { 
+			proto_tree_add_uint(wcp_tree, hf_wcp_seq,  tvb, 0, 2, seq);
+		}
+	}
+	else {
+		wcp_tree = NULL;
+	}
+
+
+					/* exit if done */
+	if ( cmd != 1 && cmd != 0 && !(cmd == 0xf && ext_cmd == 0)) 
+		return;
+
+	if ( cmd == 1) {		/* uncompressed data */
+		if ( !pinfo->fd->flags.visited){	/* if first pass */
+			wcp_save_data( tvb, pinfo);
+		}
+		next_tvb = tvb_new_subset(tvb, wcp_header_len, -1, -1);
+	}
+	else { 		/* cmd == 0 || (cmd == 0xf && ext_cmd == 0) */
+
+		next_tvb = wcp_uncompress( tvb, wcp_header_len, pinfo, wcp_tree);
+
+		if ( !next_tvb){
+			proto_tree_add_protocol_format(tree, proto_malformed, tvb, 0, 0,
+                             		"[Malformed Frame: Bad WCP compressed data]" );
+			return;
+		}
+	}
+
+	if ( tree)	 		/* add the check byte */
+		proto_tree_add_uint(wcp_tree, hf_wcp_chksum, tvb,
+			tvb_reported_length( tvb)-1, 1,
+		 	tvb_get_guint8( tvb, tvb_reported_length(tvb)-1));
+
+	protocol_id = tvb_get_guint8( next_tvb, 0);
+
+/*XXX This isn't really what we want to do !! Should be able to call a decoder	*/
+/*	routine in the frame relay code or PPP (if that is added).		*/
+
+  	if (!dissector_try_port(fr_subdissector_table, protocol_id,
+			tvb_new_subset(next_tvb, 1,-1,-1), pinfo, tree))
+		dissect_snap(next_tvb, 0, pinfo, tree, wcp_tree, 0,
+	      		hf_wcp_oui, hf_wcp_type, hf_wcp_pid, 0);
+
+	return;
+}
+
+
+guint8 *decompressed_entry( guint8 *src, guint8 *dst, int *len, guint8 * buf_start, guint8 *buf_end){
+
+/* do the decompression for one field */
+
+	guint16 data_offset, data_cnt;
+	guint8 tmp = *src;
+
+	data_offset = (*(src++) & 0xf) << 8;	/* get high byte */
+	data_offset += *(src++);		/* add next byte */
+
+	if (( tmp & 0xf0) == 0x10){		/* 2 byte count */
+		data_cnt = *src;
+		data_cnt++;
+
+	}else {					/* one byte count */
+		data_cnt = tmp >> 4;
+		data_cnt++;
+	}		
+
+	
+	src = (dst - 1 - data_offset);
+	if ( src < buf_start)
+		src += MAX_WIN_BUF_LEN;
+
+
+/*XXX could do some fancy memory moves, later if speed is problem */
+
+	while( data_cnt--){
+		*dst = *src;
+		if ( ++(*len) >MAX_WCP_BUF_LEN){
+			printf("decomp failed, len = %d\n",  *len);
+
+			return NULL;	/* end of buffer error */
+		}
+		if ( dst++ == buf_end)
+			dst = buf_start;
+		if ( src++ == buf_end)
+			src = buf_start;
+
+	}
+	return dst;
+}
+
+
+static 
+wcp_window_t *get_wcp_window_ptr( packet_info *pinfo){
+
+/* find the conversation for this side of the DLCI, create one if needed */
+/* and return the wcp_window data structure pointer */
+
+	conversation_t *conv = find_conversation( &pinfo->dl_src, &pinfo->dl_src, PT_NONE, 
+		((pinfo->pseudo_header->x25.flags & FROM_DCE)? 1:0), 
+		((pinfo->pseudo_header->x25.flags & FROM_DCE)? 1:0), 0);
+
+	if ( !conv){
+
+		conv = conversation_new( &pinfo->dl_src, &pinfo->dl_src, PT_NONE, 
+			((pinfo->pseudo_header->x25.flags & FROM_DCE)? 1:0), 
+			((pinfo->pseudo_header->x25.flags & FROM_DCE)? 1:0),
+			g_mem_chunk_alloc( wcp_window), 0);
+			
+		((wcp_window_t*)conv->data)->buf_cur = ((wcp_window_t*)conv->data)->buffer;
+	}
+
+	return (wcp_window_t*)conv->data;
+}
+
+
+static tvbuff_t *wcp_uncompress( tvbuff_t *src_tvb, int offset, packet_info *pinfo, proto_tree *tree) {
+
+/* do the packet data uncompression and load it into the dst buffer */
+
+	proto_tree	*sub_tree;
+	proto_item	*ti;
+
+	int len=0, i = -1;
+	int cnt = tvb_reported_length( src_tvb)-1;	/* don't include check byte */
+
+	guint8 *buf = 0, *dst, *src, *buf_start, *buf_end,  *tmp, comp_flag_bits = 0;
+	guint8 src_buf[ MAX_WCP_BUF_LEN];
+	tvbuff_t *tvb = 0;
+	wcp_window_t *buf_ptr = 0;
+	wcp_pdata_t *pdata_ptr;
+
+	buf_ptr = get_wcp_window_ptr( pinfo); 
+
+	buf_start = buf_ptr->buffer;
+	buf_end = buf_start + MAX_WIN_BUF_LEN;
+	tmp = buf_ptr->buf_cur;
+
+	src = tvb_memcpy(src_tvb, src_buf, offset, cnt - offset);
+	dst = buf_ptr->buf_cur;
+
+	while( offset++ < cnt){
+
+		if ( --i >= 0){
+			if ( comp_flag_bits & 0x80){	/* if this is a compressed entry */
+
+				if ( !pinfo->fd->flags.visited){	/* if first pass */
+					dst = decompressed_entry( src, dst, &len, buf_start, buf_end);
+				}
+				if ((*src & 0xf0) == 0x10){
+					ti = proto_tree_add_item( tree, hf_wcp_long_run, src_tvb,
+							 offset-1, 3, 0);
+					sub_tree = proto_item_add_subtree(ti, ett_wcp_field);
+					proto_tree_add_uint(sub_tree, hf_wcp_offset, src_tvb,
+							 offset-1, 2, pntohs(src));
+
+					proto_tree_add_item( sub_tree, hf_wcp_long_len, src_tvb,
+							 offset+1, 1, pntohs(src));
+					src += 3;
+					offset += 2;
+				}else{
+					ti = proto_tree_add_item( tree, hf_wcp_short_run, src_tvb,
+							 offset - 1, 2, *src);
+					sub_tree = proto_item_add_subtree(ti, ett_wcp_field);
+					proto_tree_add_item( sub_tree, hf_wcp_short_len, src_tvb,
+							 offset-1, 1, *src);
+					proto_tree_add_uint(sub_tree, hf_wcp_offset, src_tvb,
+							 offset-1, 2, pntohs(src));
+					src += 2;
+					offset += 1;
+				}
+			}else {
+				if ( !pinfo->fd->flags.visited){	/* if first pass */
+					*dst = *src;
+					if ( dst++ == buf_end)
+						dst = buf_start;
+				}
+				++src;
+				++len;
+
+			}
+
+			if ( len >MAX_WCP_BUF_LEN){
+				return NULL;
+			}
+
+			comp_flag_bits <<= 1;
+
+		}else {	/* compressed data flag */
+
+			comp_flag_bits = *src++;
+			proto_tree_add_uint( tree, hf_wcp_comp_bits,  src_tvb, offset-1, 1, comp_flag_bits);
+				
+			i = 8;
+		}
+	}
+
+	if ( pinfo->fd->flags.visited){	/* if not first pass */
+					/* get uncompressed data */
+		pdata_ptr = p_get_proto_data( pinfo->fd, proto_wcp);
+
+		if ( !pdata_ptr)	/* exit if no data */
+			return NULL;
+		len = pdata_ptr->len;	
+	} else {
+
+	/* save the new data as per packet data */
+		pdata_ptr = g_mem_chunk_alloc( wcp_pdata);
+		memcpy( &pdata_ptr->buffer, buf_ptr->buf_cur,  len);
+		pdata_ptr->len = len;
+
+		p_add_proto_data( pinfo->fd, proto_wcp, (void*)pdata_ptr);	
+
+		buf_ptr->buf_cur = dst;
+	}
+
+
+        TRY {
+                tvb = tvb_new_real_data( pdata_ptr->buffer, pdata_ptr->len, pdata_ptr->len, "uncompressed");
+
+        }
+        CATCH(BoundsError) {
+                g_assert_not_reached();
+		g_free(buf);
+		return NULL;
+        }
+        CATCH(ReportedBoundsError) {
+ 		g_free(buf);
+               return NULL;
+        }
+        ENDTRY; 
+
+	/* Add new data to the data source list */
+	pinfo->fd->data_src = g_slist_append( pinfo->fd->data_src, tvb);
+	return tvb;
+
+}
+
+
+static void wcp_reinit( void){
+
+/* Do the cleanup work when a new pass through the packet list is       */
+/* performed. re-initialize the  memory chunks.                         */
+
+        if (wcp_window)
+                g_mem_chunk_destroy(wcp_window);
+
+        wcp_window = g_mem_chunk_new("wcp_window", wcp_win_length,
+                wcp_win_init_count * wcp_win_length,
+                G_ALLOC_AND_FREE);
+
+        if (wcp_pdata)
+                g_mem_chunk_destroy(wcp_pdata);
+
+        wcp_pdata = g_mem_chunk_new("wcp_pdata", wcp_packet_length,
+                wcp_packet_init_count * wcp_packet_length,
+                G_ALLOC_AND_FREE);
+
+}
+
+
+void
+proto_register_wcp(void)
+{
+    static hf_register_info hf[] = {
+	{ &hf_wcp_cmd,
+	  { "Command", "wcp.cmd", FT_UINT8, BASE_HEX, VALS(cmd_string), WCP_CMD, 
+	  	"Compression Command" }},
+	{ &hf_wcp_ext_cmd,
+	  { "Extended Command", "wcp.ext_cmd", FT_UINT8, BASE_HEX, VALS(ext_cmd_string), WCP_EXT_CMD, 
+	  	"Extended Compression Command" }},
+	{ &hf_wcp_seq,
+	  { "SEQ", "wcp.seq", FT_UINT16, BASE_HEX, NULL, WCP_SEQ, 
+	  	"Sequence Number" }},
+	{ &hf_wcp_chksum,
+	  { "Checksum", "wcp.checksum", FT_UINT8, BASE_DEC, NULL, 0,
+	  	"Packet Checksum" }},
+	{ &hf_wcp_tid,
+	  { "TID", "wcp.tid", FT_UINT16, BASE_DEC, NULL, 0,
+	  	"TID" }},
+	{ &hf_wcp_rev,
+	  { "Revision", "wcp.rev", FT_UINT8, BASE_DEC, NULL, 0,
+	  	"Revision" }},
+	{ &hf_wcp_init,
+	  { "Initiator", "wcp.init", FT_UINT8, BASE_DEC, NULL, 0,
+	  	"Initiator" }},
+	{ &hf_wcp_seq_size,
+	  { "Seq Size", "wcp.seq_size", FT_UINT8, BASE_DEC, NULL, 0,
+	  	"Sequence Size"}},
+	{ &hf_wcp_alg_cnt,
+	  { "Alg Count", "wcp.alg_cnt", FT_UINT8, BASE_DEC, NULL, 0,
+	  	"Algorithm Count"}},
+	{ &hf_wcp_alg_a,
+	  { "Alg 1", "wcp.alg1", FT_UINT8, BASE_DEC, NULL, 0,
+	  	"Algorithm #1"}},
+	{ &hf_wcp_alg_b,
+	  { "Alg 2", "wcp.alg2", FT_UINT8, BASE_DEC, NULL, 0,
+	  	"Algorithm #2"}},
+	{ &hf_wcp_alg_c,
+	  { "Alg 3", "wcp.alg3", FT_UINT8, BASE_DEC, NULL, 0,
+	  	"Algorithm #3"}},
+	{ &hf_wcp_alg_d,
+	  { "Alg 4", "wcp.alg4", FT_UINT8, BASE_DEC, NULL, 0,
+	  	"Algorithm #4"}},
+	{ &hf_wcp_alg,
+	  { "Alg", "wcp.alg", FT_UINT8, BASE_DEC, NULL, 0,
+	  	"Algorithm"}},
+	{ &hf_wcp_rexmit,
+	  { "Rexmit", "wcp.rexmit", FT_UINT8, BASE_DEC, NULL, 0,
+	  	"Retransmit"}},
+	{ &hf_wcp_hist_size,
+	  { "History", "wcp.hist", FT_UINT8, BASE_DEC, NULL, 0,
+	  	"History Size"}},
+	{ &hf_wcp_ppc,
+	  { "PerPackComp", "wcp.ppc", FT_UINT8, BASE_DEC, NULL, 0,
+	  	"Per Packet Compression"}},
+	{ &hf_wcp_pib,
+	  { "PIB", "wcp.pib", FT_UINT8, BASE_DEC, NULL, 0,
+	  	"PIB"}},
+	{ &hf_wcp_comp_bits,
+	  { "Compress Flag", "wcp.flag", FT_UINT8, BASE_HEX, NULL, 0,
+	  	"Compressed byte flag"}},
+	{ &hf_wcp_comp_marker,
+	  { "Compress Marker", "wcp.mark", FT_UINT8, BASE_BIN, NULL, 0,
+	  	"Compressed marker"}},
+	{ &hf_wcp_offset,
+	  { "Source offset", "wcp.off", FT_UINT16, BASE_HEX, NULL, WCP_OFFSET_MASK,
+	  	"Data source offset"}},
+	{ &hf_wcp_short_len,
+	  { "Compress Length", "wcp.short_len", FT_UINT8, BASE_HEX, NULL, 0xf0,
+	  	"Compressed length"}},
+	{ &hf_wcp_long_len,
+	  { "Compress Length", "wcp.long_len", FT_UINT8, BASE_HEX, NULL, 0,
+	  	"Compressed length"}},
+	{ &hf_wcp_long_run,
+	  { "Long Compression", "wcp.long_comp", FT_UINT16, BASE_HEX, NULL, 0,
+	  	"Long Compression type"}},
+	{ &hf_wcp_short_run,
+	  { "Short Compression", "wcp.short_comp", FT_UINT8, BASE_HEX, NULL, 0,
+	  	"Short Compression type"}},
+	{ &hf_wcp_oui, {
+	   "Organization Code",	"wcp.snap.oui", FT_UINT24, BASE_HEX, 
+	   VALS(oui_vals), 0x0, ""}},
+	{ &hf_wcp_pid, {
+	   "Protocol ID", "wcp.snap.pid", FT_UINT16, BASE_HEX, 
+	   NULL, 0x0, ""}},
+        { &hf_wcp_type, { 
+           "Type", "wcp.type", FT_UINT16, BASE_HEX, 
+            NULL, 0x0, "WCP SNAP Encapsulated Protocol" }},
+
+   };
+
+
+    static gint *ett[] = {
+        &ett_wcp,
+	&ett_wcp_field,
+    };
+
+    proto_wcp = proto_register_protocol ("Wellfleet Compression", "WCP", "wcp");
+    proto_register_field_array (proto_wcp, hf, array_length(hf));
+    proto_register_subtree_array(ett, array_length(ett));
+    register_init_routine(&wcp_reinit);
+}
+
+
+void
+proto_reg_handoff_wcp(void) {
+
+    dissector_add("fr.ietf", NLPID_WCP, dissect_wcp, proto_wcp);
+    dissector_add("ethertype",  ETHERTYPE_WCP, dissect_wcp, proto_wcp);
+}
+
+
+