From Artem Tamazov: SAToP and CESoPSN MPLS PW support.

Introduction of decoding of MPLS payloads as CESoPSN PW (RFC5086)
and SAToP PW (RFC4553). Not supported yet:
- CESoPSN Basic NxDS0 mode.
- Decoding of <Optional> RTP Headers (RFC3550)
- Decoding of PW payload



svn path=/trunk/; revision=28181

1 files changed, 431 insertions, 0 deletions

diff --git a/epan/dissectors/packet-pw-cesopsn.c b/epan/dissectors/packet-pw-cesopsn.c
new file mode 100644
index 0000000000..97b0072ebe
--- /dev/null
+++ b/epan/dissectors/packet-pw-cesopsn.c
@@ -0,0 +1,431 @@
+/* packet-pw-satop.c
+ * Routines for CESoPSN PW dissection as per RFC5086.
+ * 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:
+ * ---------------------------------
+ * 16.03.2009 initial implementation
+ * Not supported:
+ * - All PW modes, except Basic NxDS0 mode.
+ * - <Optional> RTP Headers (RFC3550)
+ * - Decoding of PW payload
+ */
+
+#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"
+#include "packet-pw-common.h"
+
+static gint proto = -1;
+static gint ett = -1;
+
+static int hf_cw = -1;
+static int hf_cw_bits03 = -1;
+static int hf_cw_lm = -1;
+static int hf_cw_r = -1;
+static int hf_cw_frg = -1;
+static int hf_cw_len = -1;
+static int hf_cw_seq = -1;
+static int hf_payload = -1;
+static int hf_padding = -1;
+static int hf_padding_f = -1;
+
+static dissector_handle_t data_handle;
+
+static const char pwc_longname_pw_cesopsn[] = "CESoPSN basic NxDS0 mode (no RTP support)";
+static const char shortname[] = "CESoPSN basic (no RTP)";
+
+static const value_string vals_cw_lm[] = {
+	/* note that bitmask in hs_register_info is 0xb == 1011B */
+	/* this is why 0x8 comes just after 0x3 */
+	{ 0x0,	"Normal situation - no AC faults" },
+	/*{ 0x1,	"Reserved combination" },*/
+	{ 0x2,	"AC Fault - RDI condition" },
+	{ 0x3,	"Reserved for CESoPSN signaling" },
+	{ 0x8,	"AC Fault - TDM data is invalid" },
+	/*{ 0x9,	"Reserved combination" },*/
+	/*{ 0xa,	"Reserved combination" },*/
+	/*{ 0xb,	"Reserved combination" },*/
+	{ 0,	NULL }
+};
+
+static void dissect_pw_cesopsn( tvbuff_t * tvb_original, packet_info * pinfo, proto_tree * tree )
+{
+	const int encaps_size = 4; /*RTP header in encapsulation is not supported yet*/
+	gint packet_size;
+	gint payload_size;
+	gint padding_size;
+	pwc_packet_properties_t properties;
+
+	packet_size = tvb_reported_length_remaining(tvb_original, 0);
+	/*
+	 * FIXME
+	 * "4" below should be replaced by something like "min_packet_size_this_dissector"
+	 * Also call to dissect_try_cw_first_nibble() should be moved before this block
+	 */
+	if (packet_size < 4) /* 4 is smallest size which may be sensible (for PWACH dissector) */
+	{
+		if (tree)
+		{
+			proto_item  *item;
+			item = proto_tree_add_item(tree, proto, tvb_original, 0, -1, FALSE);
+			expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR,
+				"PW packet size (%d) is too small to carry sensible information"
+				,(int)packet_size);
+		}
+		if (check_col(pinfo->cinfo, COL_PROTOCOL))
+		{
+			col_set_str(pinfo->cinfo, COL_PROTOCOL, shortname);
+		}
+		if (check_col(pinfo->cinfo, COL_INFO))
+		{
+			col_set_str(pinfo->cinfo, COL_INFO,
+				"Malformed: PW packet is too small");
+		}
+		return;
+	}
+
+	if (dissect_try_cw_first_nibble(tvb_original, pinfo, tree))
+	{
+		return;
+	}
+
+	/* check how "good" is this packet */
+	/* also decide payload length from packet size and CW */
+	properties = 0;
+	if (0 != (tvb_get_guint8(tvb_original, 0) & 0xf0 /*bits03*/))
+	{
+		properties |= PWC_CW_BAD_BITS03;
+	}
+	if (0 != (tvb_get_guint8(tvb_original, 1) & 0xc0 /*frag*/))
+	{
+		properties |= PWC_CW_BAD_FRAG;
+	}
+	{
+		/* RFC5086:
+		 * [LEN (bits (10 to 15) MAY be used to carry the length of the CESoPSN
+		 * packet (defined as the size of the CESoPSN header + the payload size)
+		 * if it is less than 64 bytes, and MUST be set to zero otherwise.
+		 * Note:  If fixed RTP header is used in the encapsulation, it is
+		 * considered part of the CESoPSN header.]
+		 *
+		 * Note that this differs from RFC4385's definition of length:
+		 * [ If the MPLS payload is less than 64 bytes, the length field
+		 * MUST be set to the length of the PW payload...]
+		 *
+		 * We will use RFC5086's definition here.
+		 */
+		int cw_len;
+		gint payload_size_from_packet;
+
+		cw_len = tvb_get_guint8(tvb_original, 1) & 0x3f;
+		payload_size_from_packet = packet_size - encaps_size;
+		if (cw_len != 0)
+		{
+			gint payload_size_from_cw;
+			payload_size_from_cw = cw_len - encaps_size;
+			/*
+			 * Assumptions for error case,
+			 * will be overwritten if no errors found:
+			 */
+			payload_size = payload_size_from_packet;
+			padding_size = 0;
+			
+			if (payload_size_from_cw < 0)
+			{
+				properties |= PWC_CW_BAD_PAYLEN_LT_0;
+			}
+			else if (payload_size_from_cw > payload_size_from_packet)
+			{
+				properties |= PWC_CW_BAD_PAYLEN_GT_PACKET;
+			}
+			else if (payload_size_from_packet >= 64)
+			{
+				properties |= PWC_CW_BAD_LEN_MUST_BE_0;
+			}
+			else /* ok */
+			{
+				payload_size = payload_size_from_cw;
+				padding_size = payload_size_from_packet - payload_size_from_cw; /* >=0 */
+			}
+		}
+		else
+		{
+			payload_size = payload_size_from_packet;
+			padding_size = 0;
+		}
+	}
+	
+	{
+		guint8 cw_lm;
+		cw_lm = tvb_get_guint8(tvb_original, 0) & 0x0b /*l+mod*/;
+		if (!pwc_value_listed_in_vals(cw_lm, vals_cw_lm))
+		{
+			properties |= PWC_CW_SUSPECT_LM;
+		}
+
+		{
+			guint8 l_bit, m_bits;
+			l_bit  = (cw_lm & 0x08) >> 3;
+			m_bits = (cw_lm & 0x03) >> 0;
+			if ((l_bit == 0 && m_bits == 0x0) /*CESoPSN data packet - normal situation*/
+			    ||(l_bit == 0 && m_bits == 0x2) /*CESoPSN data packet - RDI on the AC*/ )
+			{
+				if ((payload_size == 0) || ((payload_size % 8) != 0))
+				{
+					properties |= PWC_PAY_SIZE_BAD;
+				}
+			}
+			else if (l_bit == 1 && m_bits == 0x0) /*TDM data is invalid; payload MAY be omitted*/
+			{
+				/*allow any size of payload*/
+			}
+			else /*reserved combinations*/
+			{
+				/*allow any size of payload*/
+			}
+		}
+	}
+
+	/* fill up columns*/
+	if (check_col(pinfo->cinfo, COL_PROTOCOL))
+	{
+		col_set_str(pinfo->cinfo, COL_PROTOCOL, shortname);
+	}
+	if (check_col(pinfo->cinfo, COL_INFO))
+	{
+		col_clear(pinfo->cinfo, COL_INFO);
+		if (properties & PWC_ANYOF_CW_BAD)
+		{
+			col_append_str(pinfo->cinfo, COL_INFO, "CW:Bad, ");
+		}
+		else if (properties & PWC_ANYOF_CW_SUSPECT)
+		{
+			col_append_str(pinfo->cinfo, COL_INFO, "CW:Suspect, ");
+		}
+
+		if (properties & PWC_PAY_SIZE_BAD)
+		{
+			col_append_str(pinfo->cinfo, COL_INFO, "Payload size:Bad, ");
+		}
+
+		col_append_fstr(pinfo->cinfo, COL_INFO, "TDM octets:%d", (int)payload_size);
+		
+		if (padding_size != 0)
+		{
+			col_append_fstr(pinfo->cinfo, COL_INFO, ", Padding:%d", (int)padding_size);
+		}
+	}
+		
+	if (tree)
+	{
+		proto_item* item;
+		item = proto_tree_add_item(tree, proto, tvb_original, 0, -1, FALSE);
+		pwc_item_append_cw(item,tvb_get_ntohl(tvb_original, 0),TRUE);
+		pwc_item_append_text_n_items(item,(int)payload_size,"octet");
+		{
+			proto_tree* tree;
+			tree = proto_item_add_subtree(item, ett);
+			{
+				tvbuff_t* tvb;
+				proto_item* item;
+				tvb = tvb_new_subset(tvb_original, 0, PWC_SIZEOF_CW, PWC_SIZEOF_CW);
+				item = proto_tree_add_item(tree, hf_cw, tvb, 0, -1, FALSE);
+				pwc_item_append_cw(item,tvb_get_ntohl(tvb, 0),FALSE);
+				{
+					proto_tree* tree;
+					tree = proto_item_add_subtree(item, ett);
+					{
+						proto_item* item;
+						if (properties & PWC_CW_BAD_BITS03) /*display only if value is wrong*/
+						{
+							item = proto_tree_add_item(tree, 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");
+						}
+						
+						item = proto_tree_add_item(tree, hf_cw_lm,  tvb, 0, 1, FALSE);
+						if (properties & PWC_CW_SUSPECT_LM)
+						{
+							expert_add_info_format(pinfo, item, PI_UNDECODED, PI_WARN
+								,"Reserved combination of L and Modifier bits");
+						}
+						
+						(void)proto_tree_add_item(tree, hf_cw_r, tvb, 0, 1, FALSE);
+						
+						item = proto_tree_add_item(tree, hf_cw_frg, tvb, 1, 1, FALSE);
+						if (properties & PWC_CW_BAD_FRAG)
+						{
+							expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
+								,"Fragmentation of payload is not allowed"
+								" for basic CESoPSN mode");
+						}
+				
+						item = proto_tree_add_item(tree, hf_cw_len, tvb, 1, 1, FALSE);
+						if (properties & PWC_CW_BAD_PAYLEN_LT_0)
+						{
+							expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
+								,"Bad Length: too small, must be > %d"
+								,(int)encaps_size);
+						}
+						if (properties & PWC_CW_BAD_PAYLEN_GT_PACKET)
+						{
+							expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
+								,"Bad Length: must be <= than PSN packet size (%d)"
+								,(int)packet_size);
+						}
+						if (properties & PWC_CW_BAD_LEN_MUST_BE_0)
+						{
+							expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
+								,"Bad Length: must be 0 if CESoPSN packet size (%d) is > 64"
+								,(int)packet_size);
+						}
+				
+						proto_tree_add_item(tree, hf_cw_seq, tvb, 2, 2, FALSE);
+						
+					}
+				}
+			}
+		}
+
+		/* payload */
+		if (payload_size == 0)
+		{
+			if (properties & PWC_PAY_SIZE_BAD)
+			{
+				expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
+					,"CESoPSN payload: none found. Size of payload must be <> 0");
+			}
+			else
+			{
+				expert_add_info_format(pinfo, item, PI_UNDECODED, PI_NOTE
+					,"CESoPSN payload: omitted to conserve bandwidth");
+			}
+		}
+		else
+		{
+			proto_tree* tree;
+			tree = proto_item_add_subtree(item, ett);
+			{
+				proto_item* item;
+				tvbuff_t* tvb;
+				tvb = tvb_new_subset(tvb_original, PWC_SIZEOF_CW, payload_size, payload_size);
+				item = proto_tree_add_item(tree, hf_payload, tvb, 0, -1, FALSE);
+				pwc_item_append_text_n_items(item,(int)payload_size,"octet");
+				if (properties & PWC_PAY_SIZE_BAD)
+				{
+					expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
+						,"CESoPSN packet payload size must be multiple of 8");
+				}
+				tree = proto_item_add_subtree(item, ett);
+				call_dissector(data_handle, tvb, pinfo, tree);
+			}
+		}
+		
+		/* padding */
+		if (padding_size > 0)
+		{
+			proto_tree* tree;
+			tree = proto_item_add_subtree(item, ett);
+			{
+				proto_item* item;
+				tvbuff_t* tvb;
+				tvb = tvb_new_subset(tvb_original, PWC_SIZEOF_CW + payload_size, padding_size, -1);
+				item = proto_tree_add_item(tree, hf_padding, tvb, 0, -1, FALSE);
+				pwc_item_append_text_n_items(item,(int)padding_size,"octet");
+				call_dissector(data_handle, tvb, pinfo, tree);
+			}
+		}	
+	}
+	return;
+}
+
+void proto_register_pw_cesopsn(void)
+{
+	static hf_register_info hf[] = {
+		{ &hf_cw	,{"Control Word"		,""
+				,FT_NONE			,BASE_NONE		,NULL
+				,0				,NULL			,HFILL }}
+		,{&hf_cw_bits03,{"Bits 0 to 3"			,"pwcesopsn.cw.bits03"
+				,FT_UINT8			,BASE_DEC		,NULL		
+				,0xf0				,NULL			,HFILL }}
+		,{ &hf_cw_lm, 	{"L+M bits"			,"pwcesopsn.cw.lm"
+				,FT_UINT8			,BASE_HEX		,VALS(vals_cw_lm)
+				,0x0b	  			,NULL 			,HFILL }}
+		,{&hf_cw_r,	{"R bit: Local CE-bound IWF"	,"pwcesopsn.cw.rbit"
+				,FT_UINT8			,BASE_DEC		,VALS(pwc_vals_cw_r_bit)
+				,0x04				,NULL			,HFILL }}
+		,{&hf_cw_frg,	{"Fragmentation"		,"pwcesopsn.cw.frag"
+				,FT_UINT8			,BASE_DEC		,VALS(pwc_vals_cw_frag)
+				,0xc0				,NULL			,HFILL }}
+		,{&hf_cw_len,	{"Length"			,"pwcesopsn.cw.length"
+				,FT_UINT8			,BASE_DEC		,NULL
+				,0x3f				,NULL			,HFILL }}
+		,{&hf_cw_seq,	{"Sequence number"		,"pwcesopsn.cw.seqno"
+				,FT_UINT16			,BASE_DEC		,NULL
+				,0				,NULL			,HFILL }}
+		,{&hf_payload	,{"TDM payload"			,"pwcesopsn.payload"	
+				,FT_BYTES			,BASE_HEX		,NULL			
+				,0				,NULL			,HFILL }}
+		,{&hf_padding	,{"Padding"			,"pwcesopsn.padding"	
+				,FT_BYTES			,BASE_HEX		,NULL			
+				,0				,NULL			,HFILL }}
+		,{&hf_padding_f	,{"Padding (formatted)"		,""
+				,FT_BYTES			,BASE_HEX		,NULL
+				,0				,NULL			,HFILL }}
+	};
+	
+	static gint *ett_array[] = {
+		&ett
+	};
+
+	proto = proto_register_protocol(pwc_longname_pw_cesopsn, shortname, "pwcesopsn");
+	proto_register_field_array(proto, hf, array_length(hf));
+	proto_register_subtree_array(ett_array, array_length(ett_array));
+	register_dissector("pw_cesopsn", dissect_pw_cesopsn, proto);
+	return;
+}
+
+void proto_reg_handoff_pw_cesopsn(void)
+{
+	static gboolean initialized=FALSE;
+
+	if ( !initialized )
+	{
+		dissector_handle_t h;
+		h = find_dissector("pw_cesopsn");
+		data_handle = find_dissector("data");
+		dissector_add("mpls.label", LABEL_INVALID, h);
+		initialized = TRUE;
+	}
+	return;
+}