Don't look up the mtp3 dissector (twice) for every packet: do it once at

proto_reg_handoff time and store the result.

If we don't call the mtp3 dissector on the payload then call the data dissector
to make it easier to see the payload.

svn path=/trunk/; revision=27160

1 files changed, 115 insertions, 103 deletions

diff --git a/plugins/ciscosm/packet-sm.c b/plugins/ciscosm/packet-sm.c
index abe547f3fd..53dd994f46 100644
--- a/plugins/ciscosm/packet-sm.c
+++ b/plugins/ciscosm/packet-sm.c
@@ -132,6 +132,7 @@ static int hf_sm_tag = -1;
 static gint ett_sm = -1;
 
 static dissector_handle_t sdp_handle;
+static dissector_handle_t mtp3_handle;
 static dissector_handle_t data_handle;
 
 /* Code to actually dissect the packets */
@@ -146,7 +147,7 @@ dissect_sm(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 	guint16 msg_type = 0;
 	guint16 length;
 	guint16 tag;
-	int		offset=0;
+	int     offset = 0;
 
 	sm_message_type = tvb_get_ntohl(tvb,offset);
 
@@ -157,129 +158,140 @@ dissect_sm(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 		col_add_fstr(pinfo->cinfo, COL_INFO, "Cisco SM Packet (%s)",
 			val_to_str(sm_message_type, sm_message_type_value_info,"reserved"));
 
-	if (tree) {
-		ti = proto_tree_add_item(tree, proto_sm, tvb, offset, 0, FALSE);
-		sm_tree = proto_item_add_subtree(ti, ett_sm);
+	ti = proto_tree_add_item(tree, proto_sm, tvb, offset, 0, FALSE);
+	sm_tree = proto_item_add_subtree(ti, ett_sm);
 
-		proto_tree_add_uint_format(sm_tree, hf_sm_sm_msg_type, tvb, offset, 4, sm_message_type,
-			"SM Message type: %s (0x%0x)", val_to_str(sm_message_type, sm_message_type_value, "reserved"), sm_message_type);
+	proto_tree_add_uint_format(sm_tree, hf_sm_sm_msg_type, tvb, offset, 4, sm_message_type,
+		"SM Message type: %s (0x%0x)", val_to_str(sm_message_type, sm_message_type_value, "reserved"), sm_message_type);
 
-		offset = offset + 4;
-		if (sm_message_type ==  MESSAGE_TYPE_PDU) {
-			proto_tree_add_item(sm_tree, hf_sm_protocol, tvb, offset, 2, FALSE);
-			protocol = tvb_get_ntohs(tvb,offset);
+	offset = offset + 4;
+	if (sm_message_type ==  MESSAGE_TYPE_PDU) {
+		proto_tree_add_item(sm_tree, hf_sm_protocol, tvb, offset, 2, FALSE);
+		protocol = tvb_get_ntohs(tvb,offset);
+		offset = offset + 2;
+		switch(protocol){
+		case SM_PROTOCOL_X100:
+		case SM_PROTOCOL_X122:
+			if (!tree)
+				return;
+			/* Protocol 0x100/0x122 only contains a length and then an EISUP packet */
+			proto_tree_add_item(sm_tree, hf_sm_len, tvb, offset, 2, FALSE);
+			length = tvb_get_ntohs(tvb,offset);
 			offset = offset + 2;
-			switch(protocol){
-			case SM_PROTOCOL_X100:
-			case SM_PROTOCOL_X122:
-				/* Protocol 0x100/0x122 only contains a length and then an EISUP packet */
-				proto_tree_add_item(sm_tree, hf_sm_len, tvb, offset, 2, FALSE);
-				length = tvb_get_ntohs(tvb,offset);
-				offset = offset + 2;
-				proto_item_set_len(ti, 8);
-
-				/* This should be the EISUP dissector but we havent got one
-				 * right now - so decode it as data for now ... */
-				next_tvb = tvb_new_subset(tvb, offset, length, length);
-				call_dissector(data_handle, next_tvb, pinfo, sm_tree);
-
-				break;
-			case SM_PROTOCOL_X101:
-				/* XXX Reveres enginered so this may not be correct!!! 
-				 * EISUP - used between Cisco HSI and Cisco PGW devices, 
-				 * uses RUDP with default port number 8003. 
-				 * Protocol stack is RUDP->Cisco SM->SDP. 
-				 * This implementation is PROPRIETARY 
-				 */
+			proto_item_set_len(ti, 8);
+
+			/* This should be the EISUP dissector but we havent got one
+			 * right now - so decode it as data for now ... */
+			next_tvb = tvb_new_subset(tvb, offset, length, length);
+			call_dissector(data_handle, next_tvb, pinfo, sm_tree);
+
+			break;
+		case SM_PROTOCOL_X101:
+			if (!tree)
+				return;
+			/* XXX Reveres enginered so this may not be correct!!! 
+			 * EISUP - used between Cisco HSI and Cisco PGW devices, 
+			 * uses RUDP with default port number 8003. 
+			 * Protocol stack is RUDP->Cisco SM->SDP. 
+			 * This implementation is PROPRIETARY 
+			 */
+			proto_tree_add_item(sm_tree, hf_sm_len, tvb, offset, 2, FALSE);
+			length = tvb_get_ntohs(tvb,offset);
+			offset = offset + 2;
+			proto_item_set_len(ti, length + offset);
+			/* The next stuff seems to be IP addr */
+			proto_tree_add_item(sm_tree, hf_sm_ip_addr, tvb, offset, 4, FALSE);
+			offset = offset + 4;
+			/* This part looks to be the same per session */
+			proto_tree_add_item(sm_tree, hf_sm_context, tvb, offset, 4, FALSE);
+			offset = offset +4;
+			/* Some sort of message type? */
+			proto_tree_add_item(sm_tree, hf_sm_eisup_msg_id, tvb, offset, 1, FALSE);
+			offset = offset + 1;
+			/* XXX Problem are tags 1 or two bytes???*/
+			proto_tree_add_item(sm_tree, hf_sm_tag, tvb, offset, 2, FALSE);
+
+			tag = tvb_get_ntohs(tvb,offset);
+			offset = offset +2;
+			if (tag== 0x01ac) {
 				proto_tree_add_item(sm_tree, hf_sm_len, tvb, offset, 2, FALSE);
 				length = tvb_get_ntohs(tvb,offset);
-				offset = offset + 2;
-				proto_item_set_len(ti, length + offset);
-				/* The next stuff seems to be IP addr */
-				proto_tree_add_item(sm_tree, hf_sm_ip_addr, tvb, offset, 4, FALSE);
-				offset = offset + 4;
-				/* This part looks to be the same per session */
-				proto_tree_add_item(sm_tree, hf_sm_context, tvb, offset, 4, FALSE);
-				offset = offset +4;
-				/* Some sort of message type? */
-				proto_tree_add_item(sm_tree, hf_sm_eisup_msg_id, tvb, offset, 1, FALSE);
-				offset = offset + 1;
-				/* XXX Problem are tags 1 or two bytes???*/
-				proto_tree_add_item(sm_tree, hf_sm_tag, tvb, offset, 2, FALSE);
-
-				tag = tvb_get_ntohs(tvb,offset);
 				offset = offset +2;
-				if (tag== 0x01ac) {
-					proto_tree_add_item(sm_tree, hf_sm_len, tvb, offset, 2, FALSE);
-					length = tvb_get_ntohs(tvb,offset);
-					offset = offset +2;
-					next_tvb = tvb_new_subset(tvb, offset, length, length);
-					call_dissector(sdp_handle, next_tvb, pinfo, sm_tree);
-					offset = offset+length;
+				next_tvb = tvb_new_subset(tvb, offset, length, length);
+				call_dissector(sdp_handle, next_tvb, pinfo, sm_tree);
+				offset = offset+length;
 
-				}
-				/*return;*/
-				break;
-			case SM_PROTOCOL_X114:
-				/* XXX Reveres enginered so this may not be correct!!! */
+			}
+			/*return;*/
+			break;
+		case SM_PROTOCOL_X114:
+			if (!tree)
+				return;
+			/* XXX Reveres enginered so this may not be correct!!! */
+			proto_tree_add_item(sm_tree, hf_sm_len, tvb, offset, 2, FALSE);
+			length = tvb_get_ntohs(tvb,offset);
+			offset = offset + 2;
+			proto_item_set_len(ti, length + offset);
+			/* The next stuff seems to be IP addr */
+			proto_tree_add_item(sm_tree, hf_sm_ip_addr, tvb, offset, 4, FALSE);
+			offset = offset + 4;
+			proto_tree_add_item(sm_tree, hf_sm_context, tvb, offset, 4, FALSE);
+			offset = offset +4;
+			/* Some sort of message type? */
+			proto_tree_add_item(sm_tree, hf_sm_eisup_msg_id, tvb, offset, 1, FALSE);
+			offset = offset + 1;
+			/* XXX Problem are tags 1 or two bytes???*/
+			proto_tree_add_item(sm_tree, hf_sm_tag, tvb, offset, 2, FALSE);
+
+			tag = tvb_get_ntohs(tvb,offset);
+			offset = offset +2;
+			if (tag== 0x01ac) {
 				proto_tree_add_item(sm_tree, hf_sm_len, tvb, offset, 2, FALSE);
 				length = tvb_get_ntohs(tvb,offset);
-				offset = offset + 2;
-				proto_item_set_len(ti, length + offset);
-				/* The next stuff seems to be IP addr */
-				proto_tree_add_item(sm_tree, hf_sm_ip_addr, tvb, offset, 4, FALSE);
-				offset = offset + 4;
-				proto_tree_add_item(sm_tree, hf_sm_context, tvb, offset, 4, FALSE);
-				offset = offset +4;
-				/* Some sort of message type? */
-				proto_tree_add_item(sm_tree, hf_sm_eisup_msg_id, tvb, offset, 1, FALSE);
-				offset = offset + 1;
-				/* XXX Problem are tags 1 or two bytes???*/
-				proto_tree_add_item(sm_tree, hf_sm_tag, tvb, offset, 2, FALSE);
-
-				tag = tvb_get_ntohs(tvb,offset);
 				offset = offset +2;
-				if (tag== 0x01ac) {
-					proto_tree_add_item(sm_tree, hf_sm_len, tvb, offset, 2, FALSE);
-					length = tvb_get_ntohs(tvb,offset);
-					offset = offset +2;
-					next_tvb = tvb_new_subset(tvb, offset, length, length);
-					call_dissector(sdp_handle, next_tvb, pinfo, sm_tree);
-					offset = offset+length;
+				next_tvb = tvb_new_subset(tvb, offset, length, length);
+				call_dissector(sdp_handle, next_tvb, pinfo, sm_tree);
+				offset = offset+length;
 
+			}
+			break;
+		default:
+			proto_tree_add_item(sm_tree, hf_sm_msg_id, tvb, offset, 2, FALSE);
+			offset = offset +2;
+			msg_type = tvb_get_ntohs(tvb,offset);
+			proto_tree_add_uint_format(sm_tree, hf_sm_msg_type, tvb, offset, 2, msg_type,
+				"Message type: %s (0x%0x)", val_to_str(msg_type, sm_pdu_type_value, "reserved"),
+				msg_type);
+			msg_type = tvb_get_ntohs(tvb,offset);
+			offset = offset + 2;
+			proto_tree_add_item(sm_tree, hf_sm_channel, tvb, offset, 2, FALSE);
+			offset = offset + 2;
+			proto_tree_add_item(sm_tree, hf_sm_bearer, tvb, offset, 2, FALSE);
+			offset = offset +2;
+			proto_tree_add_item(sm_tree, hf_sm_len, tvb, offset, 2, FALSE);
+			length = tvb_get_ntohs(tvb,offset);
+			offset = offset +2;
+			proto_item_set_len(ti, 16);
+
+			if (length > 0) {
+				next_tvb = tvb_new_subset(tvb, offset, length, length);
+
+				if ((msg_type == PDU_MTP3_TO_SLT || msg_type == PDU_MTP3_FROM_SLT)) {
+					call_dissector(mtp3_handle, next_tvb, pinfo, tree);
+				} else {
+					call_dissector(data_handle, next_tvb, pinfo, tree);
 				}
-				break;
-			default:
-				proto_tree_add_item(sm_tree, hf_sm_msg_id, tvb, offset, 2, FALSE);
-				offset = offset +2;
-				msg_type = tvb_get_ntohs(tvb,offset);
-				proto_tree_add_uint_format(sm_tree, hf_sm_msg_type, tvb, offset, 2, msg_type,
-					"Message type: %s (0x%0x)", val_to_str(msg_type, sm_pdu_type_value, "reserved"),
-					msg_type);
-				msg_type = tvb_get_ntohs(tvb,offset);
-				offset = offset + 2;
-				proto_tree_add_item(sm_tree, hf_sm_channel, tvb, offset, 2, FALSE);
-				offset = offset + 2;
-				proto_tree_add_item(sm_tree, hf_sm_bearer, tvb, offset, 2, FALSE);
-				offset = offset +2;
-				proto_tree_add_item(sm_tree, hf_sm_len, tvb, offset, 2, FALSE);
-				offset = offset +2;
-				proto_item_set_len(ti, 16);
 			}
 		}
 	}
 
-	if (sm_message_type ==  MESSAGE_TYPE_PDU) {
-		next_tvb = tvb_new_subset(tvb, offset, -1, -1);
-		if ((msg_type == PDU_MTP3_TO_SLT || msg_type == PDU_MTP3_FROM_SLT) && tvb_length(next_tvb) && find_dissector("mtp3"))
-			call_dissector(find_dissector("mtp3"), next_tvb, pinfo, tree);
-	}
 }
 
 void
 proto_reg_handoff_sm(void)
 {
-	sdp_handle = find_dissector("sdp");
+	sdp_handle  = find_dissector("sdp");
+	mtp3_handle = find_dissector("mtp3");
 	data_handle = find_dissector("data");
 }