From Artem Tamazov:

Added: FR MPLS PW support. Expanded: "default MPLS payload" menu.
https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=3325

svn path=/trunk/; revision=27860

1 files changed, 320 insertions, 0 deletions

diff --git a/epan/dissectors/packet-pw-fr.c b/epan/dissectors/packet-pw-fr.c
new file mode 100644
index 0000000000..3e33a4cef0
--- /dev/null
+++ b/epan/dissectors/packet-pw-fr.c
@@ -0,0 +1,320 @@
+/* packet-pw-fr.c
+ * Routines for Frame Relay MPLS PW dissection as per RFC4619.
+ * Copyright 2009, Dmitry Trebich, Artem Tamazov <artem.tamazov@tellabs.com>
+ *
+ * $Id$
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * 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.
+ *
+ * History:
+ * ---------------------------------
+ * 18.03.2009 initial implementation
+ * - FR DLCI mode
+ * Not supported yet:
+ * - Correct FR decode for encapsulations which contain fragmented FR frames.
+ * - FR DLCI Martini (legacy) mode (i.e. legacy CW).
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <glib.h>
+#include <epan/packet.h>
+#include <epan/expert.h>
+
+#include "packet-mpls.h"
+
+static gint proto_encaps = -1;
+static gint ett_encaps = -1;
+
+/*static int hf_pw_fr = -1;*/
+static int hf_cw_bits03 = -1;
+static int hf_cw_fecn = -1;
+static int hf_cw_becn = -1;
+static int hf_cw_de = -1;
+static int hf_cw_cr = -1;
+static int hf_cw_frg = -1;
+static int hf_cw_len = -1;
+static int hf_cw_seq = -1;
+
+static const value_string vals_frg[] = {
+	{ 0x0,	"Unfragmented" },
+	{ 0x1,	"First fragment" },
+	{ 0x2,	"Last fragment" },
+	{ 0x3,	"Intermediate fragment" },
+	{ 0,	NULL }
+};
+
+static hf_register_info hf[] = {
+	{&hf_cw_bits03	,{"Bits 0 to 3"		,"pwfr.bits03"	,FT_UINT8	,BASE_HEX
+			,NULL			,0xf0		,NULL
+			,HFILL }}
+	,{&hf_cw_fecn	,{"FR FECN"		,"pwfr.fecn"	,FT_UINT8	,BASE_DEC
+			,NULL			,0x08		,"FR Forward Explicit Congestion Notification bit"
+			,HFILL}}
+	,{&hf_cw_becn	,{"FR BECN"		,"pwfr.becn"	,FT_UINT8	,BASE_DEC
+			,NULL			,0x04		,"FR Backward Explicit Congestion Notification bit"
+			,HFILL}}
+	,{&hf_cw_de	,{"FR DE bit"		,"pwfr.de"	,FT_UINT8	,BASE_DEC
+			,NULL			,0x02		,"FR Discard Eligibility bit"
+			,HFILL}}
+	,{&hf_cw_cr	,{"FR Frame C/R"	,"pwfr.cr"	,FT_UINT8	,BASE_DEC
+			,NULL			,0x01		,"FR frame Command/Response bit"
+			,HFILL}}
+	,{&hf_cw_frg	,{"Fragmentation"	,"pwfr.frag"	,FT_UINT8	,BASE_DEC
+			,vals_frg		,0xc0		,NULL
+			,HFILL}}
+	,{&hf_cw_len	,{"Length"		,"pwfr.length"	,FT_UINT8	,BASE_DEC
+			,NULL			,0x3f		,NULL
+			,HFILL}}
+	,{&hf_cw_seq	,{"Sequence number"	,"pwfr.length"	,FT_UINT16	,BASE_DEC
+			,NULL			,0		,NULL
+			,HFILL}}
+};
+
+static gint *ett[] = {
+	&ett_encaps
+};
+
+static dissector_handle_t fr_stripped_address_handle;
+
+
+static void
+dissect_pw_fr( tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree )
+{
+	gint packet_size;
+	gint payload_size;
+	gint payload_padding;
+	const int encaps_size = 4; /*encapsulation consists of mandatory CW only*/
+	enum {
+		PQ_CW_BAD				= 0x001
+		    ,PQ_CW_BAD_BITS03 			= 0x002
+		    ,PQ_CW_BAD_LEN_GT_PACKET		= 0x004
+		    ,PQ_CW_BAD_LEN_MUST_BE_ZERO		= 0x008
+		    ,PQ_CW_BAD_LEN_MUST_BE_NONZERO	= 0x010
+		,PQ_PAYLOAD_SIZE_ZERO			= 0x020
+	} packet_quality;
+	
+	packet_size = tvb_reported_length_remaining(tvb, 0);
+	if (packet_size < encaps_size)
+	{
+		if (tree)
+		{
+			proto_item  *item;
+			item = proto_tree_add_item(tree, proto_encaps, tvb, 0, -1, FALSE); 
+			expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR,
+				"PW packet (%d) is smaller than PW encapsulation header (%d)"
+				,(int)packet_size,(int)encaps_size);
+		}
+		if (check_col(pinfo->cinfo, COL_PROTOCOL))   
+		{
+			col_set_str(pinfo->cinfo, COL_PROTOCOL, "FR PW");
+		}
+		if (check_col(pinfo->cinfo, COL_INFO))
+		{
+			col_set_str(pinfo->cinfo, COL_INFO, 
+				"Malformed: PW packet < PW encapsulation header");
+		}
+		return;
+	}
+
+	if (dissect_try_cw_first_nibble(tvb,pinfo,tree))
+	{
+		return;
+	}
+
+	/* check how "good" is this packet */   
+	/* also decide payload length from packet size and CW */
+	packet_quality = 0;
+	if (0 != (tvb_get_guint8(tvb, 0) & 0xf0 /*bits03*/))
+	{
+		packet_quality |= PQ_CW_BAD + PQ_CW_BAD_BITS03;
+	}
+	{
+		/* RFC4619:
+		 * [ If the frame's length (defined as the
+		 * length of the layer 2 payload plus the length of the control word)
+		 * is less than 64 octets, the length field MUST be set to the PW
+		 * payload length.  Otherwise, the length field MUST be set to zero. ] 
+		 * 
+		 * Note difference from RFC4385 which states that:  
+		 * [..the length field MUST be set to the length of the PW payload 
+		 * *plus* the length of the *PWMCW*. ]
+		 */
+		int cw_len;
+		gint payload_size_packet; /*derived from packet size*/
+
+		cw_len = tvb_get_guint8(tvb, 1) & 0x3f; 
+		payload_size_packet = packet_size - encaps_size;
+		
+		/* 
+		 * Initial assumptions.
+		 */
+		payload_size = payload_size_packet; 
+		payload_padding = 0;  
+		
+		if (payload_size_packet < 64)
+		{
+			gint payload_size_cw; /*derived from cw*/
+			payload_size_cw = cw_len; /*RFC4619-specific*/ 
+			if (payload_size_cw == 0)
+			{
+				packet_quality |= PQ_CW_BAD + PQ_CW_BAD_LEN_MUST_BE_NONZERO;
+			}
+			else if (payload_size_cw > payload_size_packet)
+			{
+				packet_quality |= PQ_CW_BAD + PQ_CW_BAD_LEN_GT_PACKET;
+			}
+			else /* ok */
+			{
+				payload_size = payload_size_cw;
+				payload_padding = payload_size_packet - payload_size_cw; /* >=0 */
+			}
+		}
+		else /* payload_size_packet >= 64 */
+		{          
+			if (cw_len != 0)
+			{
+				packet_quality |= PQ_CW_BAD + PQ_CW_BAD_LEN_MUST_BE_ZERO;
+			}
+		}
+	}
+	if ((payload_size == 0))
+	{		
+		packet_quality |= PQ_PAYLOAD_SIZE_ZERO;
+	}
+
+	if (check_col(pinfo->cinfo, COL_PROTOCOL))   
+	{
+		col_set_str(pinfo->cinfo, COL_PROTOCOL, "FR PW");
+	}  
+	if (check_col(pinfo->cinfo, COL_INFO))
+	{
+		col_clear(pinfo->cinfo, COL_INFO);
+		if (packet_quality & PQ_CW_BAD) 
+		{
+			col_append_str(pinfo->cinfo, COL_INFO, "CW:Malformed, ");
+		}
+		col_append_fstr(pinfo->cinfo, COL_INFO, "%d payload octets", (int)payload_size);
+	
+		if (payload_padding != 0)
+		{
+			col_append_fstr(pinfo->cinfo, COL_INFO, ", %d padding", (int)payload_padding);
+		}
+	}
+
+	if (tree)
+	{
+		proto_tree* subtree;
+		proto_item* item_headline;
+		proto_item* item;
+		
+		item_headline = proto_tree_add_item(tree, proto_encaps, tvb, 0, 4, FALSE); 
+		proto_item_append_text(item_headline, ": 0x%.8" G_GINT32_MODIFIER "x", tvb_get_ntohl(tvb, 0));
+		subtree = proto_item_add_subtree(item_headline, ett_encaps);
+		
+		if (packet_quality & PQ_CW_BAD_BITS03) /*display only if value is wrong*/
+		{
+			item = proto_tree_add_item(subtree, hf_cw_bits03, tvb, 0, 1, FALSE);
+			expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR,
+				"Bits 0..3 of Control Word must be 0");
+		}
+		
+		(void)proto_tree_add_item( subtree, hf_cw_fecn, tvb, 0, 1, FALSE );
+		(void)proto_tree_add_item( subtree, hf_cw_becn, tvb, 0, 1, FALSE );
+		(void)proto_tree_add_item( subtree, hf_cw_de, tvb, 0, 1, FALSE );
+		(void)proto_tree_add_item( subtree, hf_cw_cr, tvb, 0, 1, FALSE );
+		(void)proto_tree_add_item( subtree, hf_cw_frg, tvb, 1, 1, FALSE );
+		
+		item = proto_tree_add_item( subtree, hf_cw_len, tvb, 1, 1, FALSE );
+		if (packet_quality & PQ_CW_BAD_LEN_GT_PACKET)
+		{
+			expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR,
+				"Bad Length: greater than FR payload size (%d)", 
+				(int)payload_size);
+		}  
+		if (packet_quality & PQ_CW_BAD_LEN_MUST_BE_NONZERO)
+		{
+			expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR,
+				"Bad Length: must be non-zero if FR PW packet size (%d) is < 64",
+				(int)(payload_size+encaps_size));
+		}
+		if (packet_quality & PQ_CW_BAD_LEN_MUST_BE_ZERO)
+		{
+			expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR,
+				"Bad Length: must be 0 if FR PW packet size (%d) is >= 64",
+				(int)(payload_size+encaps_size));
+		}
+		
+		proto_tree_add_item( subtree, hf_cw_seq, tvb, 2, 2, FALSE );
+
+		if (payload_padding > 0)
+		{
+			proto_tree_add_text(subtree, tvb, 
+				encaps_size+payload_size, payload_padding, 
+				"[Padding: %d octets]",(int)payload_padding);
+		}               
+
+		if (packet_quality & PQ_PAYLOAD_SIZE_ZERO)
+		{
+			expert_add_info_format(pinfo, item_headline, PI_MALFORMED, PI_WARN,
+				"FR payload size must be non-zero");
+		}
+
+	}
+	if (payload_size > 0)
+	{
+		tvbuff_t *tvb_payload;
+		tvb_payload = tvb_new_subset(tvb, encaps_size, payload_size, payload_size);
+		call_dissector( fr_stripped_address_handle, tvb_payload, pinfo, tree );
+	} 
+	return;
+}
+
+
+void
+proto_register_pw_fr(void)
+{
+	proto_encaps = proto_register_protocol( "PW Frame Relay DLCI Control Word",
+						"Frame Relay DLCI PW",
+						"pwfr");
+	proto_register_field_array(proto_encaps, hf, array_length(hf));
+	proto_register_subtree_array(ett, array_length(ett));
+	register_dissector("pw_fr", dissect_pw_fr, proto_encaps );
+}
+
+
+void
+proto_reg_handoff_pw_fr(void)
+{
+	static gboolean initialized=FALSE;
+
+	if ( !initialized )
+	{
+		dissector_handle_t h;
+		h = find_dissector("pw_fr");
+		dissector_add("mpls.label", LABEL_INVALID, h);
+		fr_stripped_address_handle = find_dissector("fr_stripped_address");
+		initialized = TRUE;
+	}
+}