Heuristics length check must use captured_length; Do other misc changes:

- Use tvb_reported_length() iso tvb_length() in various places;
- Add some 'if(tree) {...}';
- Remove an unneeded length-check;
- Use a consistent formatting style for hf[]array entries;
- Do some minor whitespace changes;
- Add editor modelines.

Change-Id: Iac0a74142c5a5944e69fc911e54b0fbdfd1f5bab
Reviewed-on: https://code.wireshark.org/review/717
Reviewed-by: Bill Meier <wmeier@newsguy.com>
Tested-by: Bill Meier <wmeier@newsguy.com>

1 files changed, 185 insertions, 164 deletions

diff --git a/epan/dissectors/packet-udt.c b/epan/dissectors/packet-udt.c
index 5c95f5556c..8f0dbd290b 100644
--- a/epan/dissectors/packet-udt.c
+++ b/epan/dissectors/packet-udt.c
@@ -55,21 +55,21 @@ void proto_reg_handoff_udt(void);
 static const value_string udt_packet_types[] = {
 	{UDT_PACKET_TYPE_HANDSHAKE, "handshake"},
 	{UDT_PACKET_TYPE_KEEPALIVE, "keepalive"},
-	{UDT_PACKET_TYPE_ACK, "ack"},
-	{UDT_PACKET_TYPE_NAK, "nak"},
-	{UDT_PACKET_TYPE_SHUTDOWN, "shutdown"},
-	{UDT_PACKET_TYPE_ACK2, "ack2"},
+	{UDT_PACKET_TYPE_ACK,       "ack"},
+	{UDT_PACKET_TYPE_NAK,       "nak"},
+	{UDT_PACKET_TYPE_SHUTDOWN,  "shutdown"},
+	{UDT_PACKET_TYPE_ACK2,      "ack2"},
 	{0, NULL},
 };
 
 static const value_string udt_handshake_types[] = {
 	{UDT_HANDSHAKE_TYPE_STREAM, "STREAM"},
-	{UDT_HANDSHAKE_TYPE_DGRAM, "DGRAM"},
+	{UDT_HANDSHAKE_TYPE_DGRAM,  "DGRAM"},
 	{0, NULL},
 };
 
 static const value_string udt_types[] = {
-	{UDT_TYPE_DATA, "DATA"},
+	{UDT_TYPE_DATA,    "DATA"},
 	{UDT_TYPE_CONTROL, "CONTROL"},
 	{0, NULL},
 };
@@ -110,17 +110,13 @@ static dissector_handle_t udt_handle;
 static dissector_handle_t data_handle;
 
 static int
-dissect_udt(tvbuff_t * tvb, packet_info * pinfo, proto_tree * parent_tree,
+dissect_udt(tvbuff_t *tvb, packet_info* pinfo, proto_tree *parent_tree,
 	    void *data _U_)
 {
 	proto_tree *tree;
 	proto_item *udt_item;
-	int is_control, type;
-	guint i;
-
-	/* Ensure we have enough data */
-	if (tvb_length(tvb) < 16)
-		return 0;
+	int         is_control, type;
+	guint       i;
 
 	col_set_str(pinfo->cinfo, COL_PROTOCOL, "UDT");
 	col_clear(pinfo->cinfo, COL_INFO);
@@ -146,74 +142,80 @@ dissect_udt(tvbuff_t * tvb, packet_info * pinfo, proto_tree * parent_tree,
 
 	proto_tree_add_item(tree, hf_udt_iscontrol, tvb, 0, 4, ENC_BIG_ENDIAN);
 	if (is_control) {
-		proto_tree_add_item(tree, hf_udt_type, tvb, 0, 2,
-				    ENC_BIG_ENDIAN);
-		switch (type) {
-		case UDT_PACKET_TYPE_ACK:
-			proto_tree_add_item(tree, hf_udt_ackno, tvb, 4, 4,
+		if (tree) {
+			proto_tree_add_item(tree, hf_udt_type, tvb, 0, 2,
 					    ENC_BIG_ENDIAN);
-			break;
-		case UDT_PACKET_TYPE_ACK2:
-			proto_tree_add_item(tree, hf_udt_ackno, tvb, 4, 4,
+			switch (type) {
+			case UDT_PACKET_TYPE_ACK:
+				proto_tree_add_item(tree, hf_udt_ackno, tvb, 4, 4,
+						    ENC_BIG_ENDIAN);
+				break;
+			case UDT_PACKET_TYPE_ACK2:
+				proto_tree_add_item(tree, hf_udt_ackno, tvb, 4, 4,
+						    ENC_BIG_ENDIAN);
+				break;
+			default:
+				proto_tree_add_item(tree, hf_udt_addinfo, tvb, 4, 4,
+						    ENC_BIG_ENDIAN);
+			}
+			proto_tree_add_item(tree, hf_udt_timestamp, tvb, 8, 4,
 					    ENC_BIG_ENDIAN);
-			break;
-		default:
-			proto_tree_add_item(tree, hf_udt_addinfo, tvb, 4, 4,
+			proto_tree_add_item(tree, hf_udt_id, tvb, 12, 4,
 					    ENC_BIG_ENDIAN);
 		}
-		proto_tree_add_item(tree, hf_udt_timestamp, tvb, 8, 4,
-				    ENC_BIG_ENDIAN);
-		proto_tree_add_item(tree, hf_udt_id, tvb, 12, 4,
-				    ENC_BIG_ENDIAN);
 
 		switch (type) {
 		case UDT_PACKET_TYPE_HANDSHAKE:
-			proto_tree_add_item(tree, hf_udt_handshake_version, tvb,
-					    16, 4, ENC_BIG_ENDIAN);
-			proto_tree_add_item(tree, hf_udt_handshake_type, tvb,
-					    20, 4, ENC_BIG_ENDIAN);
-			proto_tree_add_item(tree, hf_udt_handshake_isn, tvb, 24,
-					    4, ENC_BIG_ENDIAN);
-			proto_tree_add_item(tree, hf_udt_handshake_mtu, tvb, 28,
-					    4, ENC_BIG_ENDIAN);
-			proto_tree_add_item(tree, hf_udt_handshake_flow_window,
-					    tvb, 32, 4, ENC_BIG_ENDIAN);
-			proto_tree_add_item(tree, hf_udt_handshake_reqtype, tvb,
-					    36, 4, ENC_BIG_ENDIAN);
-			proto_tree_add_item(tree, hf_udt_handshake_id, tvb, 40,
-					    4, ENC_BIG_ENDIAN);
-			proto_tree_add_item(tree, hf_udt_handshake_cookie, tvb,
-					    44, 4, ENC_BIG_ENDIAN);
-			proto_tree_add_item(tree, hf_udt_handshake_peerip, tvb,
-					    48, 16, ENC_NA);
-			proto_item_set_len(udt_item, 64);
+			if (tree) {
+				proto_tree_add_item(tree, hf_udt_handshake_version, tvb,
+						    16,  4, ENC_BIG_ENDIAN);
+				proto_tree_add_item(tree, hf_udt_handshake_type, tvb,
+						    20,  4, ENC_BIG_ENDIAN);
+				proto_tree_add_item(tree, hf_udt_handshake_isn, tvb,
+						    24,  4, ENC_BIG_ENDIAN);
+				proto_tree_add_item(tree, hf_udt_handshake_mtu, tvb,
+						    28,  4, ENC_BIG_ENDIAN);
+				proto_tree_add_item(tree, hf_udt_handshake_flow_window, tvb,
+						    32,  4, ENC_BIG_ENDIAN);
+				proto_tree_add_item(tree, hf_udt_handshake_reqtype, tvb,
+						    36,  4, ENC_BIG_ENDIAN);
+				proto_tree_add_item(tree, hf_udt_handshake_id, tvb,
+						    40,  4, ENC_BIG_ENDIAN);
+				proto_tree_add_item(tree, hf_udt_handshake_cookie, tvb,
+						    44,  4, ENC_BIG_ENDIAN);
+				proto_tree_add_item(tree, hf_udt_handshake_peerip, tvb,
+						    48, 16, ENC_NA);
+				proto_item_set_len(udt_item, 64);
+			}
 			break;
 		case UDT_PACKET_TYPE_ACK:
-			proto_tree_add_item(tree, hf_udt_ack_seqno, tvb, 16, 4,
-					    ENC_BIG_ENDIAN);
-			proto_tree_add_item(tree, hf_udt_rtt, tvb, 20, 4,
-					    ENC_BIG_ENDIAN);
-			proto_tree_add_item(tree, hf_udt_rttvar, tvb, 24, 4,
-					    ENC_BIG_ENDIAN);
-			proto_tree_add_item(tree, hf_udt_bufavail, tvb, 28, 4,
-					    ENC_BIG_ENDIAN);
-			/* if not a light ack, decode the rate and link capacity */
-			if (tvb_length(tvb) == 40) {
-				proto_tree_add_item(tree, hf_udt_rate, tvb, 32,
-						    4, ENC_BIG_ENDIAN);
-				proto_tree_add_item(tree, hf_udt_linkcap, tvb,
-						    36, 4, ENC_BIG_ENDIAN);
-				proto_item_set_len(udt_item, 40);
-			}
-			else
-			{
-				proto_item_set_len(udt_item, 32);
+			if (tree) {
+				proto_tree_add_item(tree, hf_udt_ack_seqno, tvb, 16, 4,
+						    ENC_BIG_ENDIAN);
+				proto_tree_add_item(tree, hf_udt_rtt,      tvb, 20, 4,
+						    ENC_BIG_ENDIAN);
+				proto_tree_add_item(tree, hf_udt_rttvar,   tvb, 24, 4,
+						    ENC_BIG_ENDIAN);
+				proto_tree_add_item(tree, hf_udt_bufavail, tvb, 28, 4,
+						    ENC_BIG_ENDIAN);
+				/* if not a light ack, decode the rate and link capacity */
+				if (tvb_reported_length(tvb) == 40) {
+					proto_tree_add_item(tree, hf_udt_rate, tvb,
+							    32, 4, ENC_BIG_ENDIAN);
+					proto_tree_add_item(tree, hf_udt_linkcap, tvb,
+							    36, 4, ENC_BIG_ENDIAN);
+					proto_item_set_len(udt_item, 40);
+				}
+				else
+				{
+					proto_item_set_len(udt_item, 32);
+				}
 			}
 			break;
 		case UDT_PACKET_TYPE_NAK:
-			for (i = 16; i < tvb_length(tvb); i = i + 4) {
+			for (i = 16; i < tvb_reported_length(tvb); i = i + 4) {
 				guint32 start, finish;
-				int is_range;
+				int     is_range;
 
 				is_range = tvb_get_ntohl(tvb, i) & 0x80000000;
 				start = tvb_get_ntohl(tvb, i) & 0x7fffffff;
@@ -232,33 +234,35 @@ dissect_udt(tvbuff_t * tvb, packet_info * pinfo, proto_tree * parent_tree,
 				}
 			}
 
-			proto_item_set_len(udt_item, tvb_length(tvb));
+			proto_item_set_len(udt_item, tvb_reported_length(tvb));
 			break;
 		}
 	} else {
 		/* otherwise, a data packet */
 		tvbuff_t *next_tvb;
 
-		proto_tree_add_item(tree, hf_udt_seqno, tvb, 0, 4,
-				    ENC_BIG_ENDIAN);
-		proto_tree_add_item(tree, hf_udt_msgno_first, tvb, 4, 4,
-				    ENC_BIG_ENDIAN);
-		proto_tree_add_item(tree, hf_udt_msgno_last, tvb, 4, 4,
-				    ENC_BIG_ENDIAN);
-		proto_tree_add_item(tree, hf_udt_msgno_inorder, tvb, 4, 4,
-				    ENC_BIG_ENDIAN);
-		proto_tree_add_item(tree, hf_udt_msgno, tvb, 4, 4,
-				    ENC_BIG_ENDIAN);
-		proto_tree_add_item(tree, hf_udt_timestamp, tvb, 8, 4,
-				    ENC_BIG_ENDIAN);
-		proto_tree_add_item(tree, hf_udt_id, tvb, 12, 4,
-				    ENC_BIG_ENDIAN);
+		if (tree) {
+			proto_tree_add_item(tree, hf_udt_seqno,		tvb,  0, 4,
+					    ENC_BIG_ENDIAN);
+			proto_tree_add_item(tree, hf_udt_msgno_first,	tvb,  4, 4,
+					    ENC_BIG_ENDIAN);
+			proto_tree_add_item(tree, hf_udt_msgno_last,	tvb,  4, 4,
+					    ENC_BIG_ENDIAN);
+			proto_tree_add_item(tree, hf_udt_msgno_inorder, tvb,  4, 4,
+					    ENC_BIG_ENDIAN);
+			proto_tree_add_item(tree, hf_udt_msgno,		tvb,  4, 4,
+					    ENC_BIG_ENDIAN);
+			proto_tree_add_item(tree, hf_udt_timestamp,	tvb,  8, 4,
+					    ENC_BIG_ENDIAN);
+			proto_tree_add_item(tree, hf_udt_id,		tvb, 12, 4,
+					    ENC_BIG_ENDIAN);
 
+		}
 		next_tvb = tvb_new_subset_remaining(tvb, 16);
-		call_dissector(data_handle, next_tvb, pinfo, parent_tree);
+		call_dissector(data_handle, next_tvb, pinfo, tree);
 	}
 
-	return tvb_length(tvb);
+	return tvb_reported_length(tvb);
 }
 
 static gboolean
@@ -266,9 +270,9 @@ dissect_udt_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data
 {
 	conversation_t *conv;
 
-	/* Must have at least 20 bytes */
-	if (tvb_reported_length(tvb) < 20)
-		return 0;
+	/* Must have at least 24 captured bytes for heuristic check */
+	if (tvb_captured_length(tvb) < 24)
+		return FALSE;
 
 	/* detect handshake control packet */
 	if (tvb_get_ntohl(tvb, 0) != (0x80000000 | UDT_PACKET_TYPE_HANDSHAKE))
@@ -296,132 +300,135 @@ void proto_register_udt(void)
 
 	static hf_register_info hf[] = {
 		{&hf_udt_iscontrol, {
-				     "Type", "udt.iscontrol", FT_UINT32,
-				     BASE_DEC,
-				     VALS(udt_types), 0x80000000, NULL, HFILL}},
+				"Type", "udt.iscontrol",
+				 FT_UINT32, BASE_DEC,
+				VALS(udt_types), 0x80000000, NULL, HFILL}},
 
 		{&hf_udt_type, {
-				"Type", "udt.type", FT_UINT16, BASE_HEX,
+				"Type", "udt.type",
+				FT_UINT16, BASE_HEX,
 				VALS(udt_packet_types), 0x7fff, NULL, HFILL}},
 
 		{&hf_udt_seqno, {
-				 "Sequence Number", "udt.seqno", FT_UINT32,
-				 BASE_DEC,
-				 NULL, 0x7fffffff, NULL, HFILL}},
+				"Sequence Number", "udt.seqno",
+				FT_UINT32, BASE_DEC,
+				NULL, 0x7fffffff, NULL, HFILL}},
 
 		{&hf_udt_addinfo, {
-				   "Additional Info", "udt.addinfo", FT_UINT32,
-				   BASE_DEC,
-				   NULL, 0, NULL, HFILL}},
+				"Additional Info", "udt.addinfo",
+				FT_UINT32, BASE_DEC,
+				NULL, 0, NULL, HFILL}},
 
 		{&hf_udt_msgno, {
-				 "Message Number", "udt.msgno", FT_UINT32,
-				 BASE_DEC,
-				 NULL, 0x1fffffff, NULL, HFILL}},
+				"Message Number", "udt.msgno",
+				FT_UINT32, BASE_DEC,
+				NULL, 0x1fffffff, NULL, HFILL}},
 
 		{&hf_udt_msgno_first, {
-				       "First Indicator", "udt.msg.first",
-				       FT_UINT32, BASE_DEC,
-				       NULL, 0x80000000, NULL, HFILL}},
+				"First Indicator", "udt.msg.first",
+				FT_UINT32, BASE_DEC,
+				NULL, 0x80000000, NULL, HFILL}},
 
 		{&hf_udt_msgno_last, {
-				      "Last Indicator", "udt.msg.last",
-				      FT_UINT32, BASE_DEC,
-				      NULL, 0x40000000, NULL, HFILL}},
+				"Last Indicator", "udt.msg.last",
+				FT_UINT32, BASE_DEC,
+				NULL, 0x40000000, NULL, HFILL}},
 
 		{&hf_udt_msgno_inorder, {
-					 "In-Order Indicator", "udt.msg.order",
-					 FT_UINT32, BASE_DEC,
-					 NULL, 0x20000000, NULL, HFILL}},
+				"In-Order Indicator", "udt.msg.order",
+				FT_UINT32, BASE_DEC,
+				NULL, 0x20000000, NULL, HFILL}},
 
 		{&hf_udt_timestamp, {
-				     "Timestamp", "udt.timestamp", FT_UINT32,
-				     BASE_DEC,
-				     NULL, 0, NULL, HFILL}},
+				"Timestamp", "udt.timestamp",
+				FT_UINT32, BASE_DEC,
+				NULL, 0, NULL, HFILL}},
 
 		{&hf_udt_id, {
-			      "ID", "udt.id", FT_UINT32, BASE_HEX,
-			      NULL, 0, NULL, HFILL}},
+				"ID", "udt.id",
+				FT_UINT32, BASE_HEX,
+				NULL, 0, NULL, HFILL}},
 
 		{&hf_udt_ack_seqno, {
-				     "Ack Sequence Number", "udt.ack_seqno",
-				     FT_UINT32, BASE_DEC,
-				     NULL, 0, NULL, HFILL}},
+				"Ack Sequence Number", "udt.ack_seqno",
+				FT_UINT32, BASE_DEC,
+				NULL, 0, NULL, HFILL}},
 
 		{&hf_udt_ackno, {
-				 "Ack Number", "udt.ackno", FT_UINT32, BASE_DEC,
-				 NULL, 0, NULL, HFILL}},
+				"Ack Number", "udt.ackno",
+				FT_UINT32, BASE_DEC,
+				NULL, 0, NULL, HFILL}},
 
 		{&hf_udt_rtt, {
-			       "RTT (microseconds)", "udt.rtt", FT_UINT32,
-			       BASE_DEC,
-			       NULL, 0, NULL, HFILL}},
+				"RTT (microseconds)", "udt.rtt",
+				FT_UINT32, BASE_DEC,
+				NULL, 0, NULL, HFILL}},
 
 		{&hf_udt_rttvar, {
-				  "RTT Variance (microseconds)", "udt.rttvar",
-				  FT_UINT32, BASE_DEC,
-				  NULL, 0, NULL, HFILL}},
+				"RTT Variance (microseconds)", "udt.rttvar",
+				FT_UINT32, BASE_DEC,
+				NULL, 0, NULL, HFILL}},
 
 		{&hf_udt_bufavail, {
-				    "Buffer Available (packets)", "udt.rttvar",
-				    FT_UINT32, BASE_DEC,
-				    NULL, 0, NULL, HFILL}},
+				"Buffer Available (packets)", "udt.rttvar",
+				FT_UINT32, BASE_DEC,
+				NULL, 0, NULL, HFILL}},
 
 		{&hf_udt_rate, {
-				"Rate (packets/second)", "udt.rate", FT_UINT32,
-				BASE_DEC,
+				"Rate (packets/second)", "udt.rate",
+				FT_UINT32, BASE_DEC,
 				NULL, 0, NULL, HFILL}},
 
 		{&hf_udt_linkcap, {
-				   "Link Capacity (packets/second)",
-				   "udt.linkcap", FT_UINT32, BASE_DEC,
-				   NULL, 0, NULL, HFILL}},
+				"Link Capacity (packets/second)", "udt.linkcap",
+				FT_UINT32, BASE_DEC,
+				NULL, 0, NULL, HFILL}},
 
 		{&hf_udt_handshake_version, {
-					     "Version", "udt.hs.version",
-					     FT_UINT32, BASE_DEC,
-					     NULL, 0, NULL, HFILL}},
+				"Version", "udt.hs.version",
+				FT_UINT32, BASE_DEC,
+				NULL, 0, NULL, HFILL}},
 
 		{&hf_udt_handshake_type, {
-					  "Type", "udt.hs.type", FT_UINT32,
-					  BASE_DEC,
-					  VALS(udt_handshake_types), 0, NULL,
-					  HFILL}},
+				"Type", "udt.hs.type",
+				FT_UINT32, BASE_DEC,
+				VALS(udt_handshake_types), 0, NULL,
+				HFILL}},
 
 		{&hf_udt_handshake_isn, {
-					 "Initial Sequence Number",
-					 "udt.hs.isn", FT_UINT32, BASE_DEC,
-					 NULL, 0, NULL, HFILL}},
+				"Initial Sequence Number", "udt.hs.isn",
+				FT_UINT32, BASE_DEC,
+				NULL, 0, NULL, HFILL}},
 
 		{&hf_udt_handshake_mtu, {
-					 "MTU", "udt.hs.mtu", FT_UINT32,
-					 BASE_DEC,
-					 NULL, 0, NULL, HFILL}},
+				"MTU", "udt.hs.mtu",
+				FT_UINT32, BASE_DEC,
+				NULL, 0, NULL, HFILL}},
 
 		{&hf_udt_handshake_flow_window, {
-						 "Flow Window",
-						 "udt.hs.flow_window",
-						 FT_UINT32, BASE_DEC,
-						 NULL, 0, NULL, HFILL}},
+				"Flow Window", "udt.hs.flow_window",
+				FT_UINT32, BASE_DEC,
+				NULL, 0, NULL, HFILL}},
 
 		{&hf_udt_handshake_reqtype, {
-					     "Requested Type", "udt.hs.reqtype",
-					     FT_INT32, BASE_DEC,
-					     NULL, 0, NULL, HFILL}},
+				"Requested Type", "udt.hs.reqtype",
+				FT_INT32, BASE_DEC,
+				NULL, 0, NULL, HFILL}},
 
 		{&hf_udt_handshake_id, {
-					"ID", "udt.hs.id", FT_UINT32, BASE_DEC,
-					NULL, 0, NULL, HFILL}},
+				"ID", "udt.hs.id",
+				FT_UINT32, BASE_DEC,
+				NULL, 0, NULL, HFILL}},
 
 		{&hf_udt_handshake_cookie, {
-					    "SYN Cookie", "udt.hs.cookie",
-					    FT_UINT32, BASE_HEX,
-					    NULL, 0, NULL, HFILL}},
+				"SYN Cookie", "udt.hs.cookie",
+				FT_UINT32, BASE_HEX,
+				NULL, 0, NULL, HFILL}},
 
 		{&hf_udt_handshake_peerip, {
-					    "Peer IP Address", "udt.hs.peerip",
-					    FT_BYTES, BASE_NONE,
-					    NULL, 0, NULL, HFILL}},
+				"Peer IP Address", "udt.hs.peerip",
+				FT_BYTES, BASE_NONE,
+				NULL, 0, NULL, HFILL}},
 	};
 
 	static gint *ett[] = {
@@ -432,7 +439,7 @@ void proto_register_udt(void)
 		{ &ei_udt_nak_seqno,
 		  { "udt.nak_seqno", PI_SEQUENCE, PI_NOTE,
 		    "Missing Sequence Number(s)", EXPFILL }},
-        };
+	};
 
 	proto_udt = proto_register_protocol("UDT Protocol", "UDT", "udt");
 	proto_register_field_array(proto_udt, hf, array_length(hf));
@@ -445,8 +452,22 @@ void proto_register_udt(void)
 void proto_reg_handoff_udt(void)
 {
 	data_handle = find_dissector("data");
-	udt_handle = new_create_dissector_handle(dissect_udt, proto_udt);
+	udt_handle  = new_create_dissector_handle(dissect_udt, proto_udt);
 
 	heur_dissector_add("udp", dissect_udt_heur, proto_udt);
 	dissector_add_handle("udp.port", udt_handle);
 }
+
+
+/*
+ * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
+ *
+ * Local variables:
+ * c-basic-offset: 8
+ * tab-width: 8
+ * indent-tabs-mode: t
+ * End:
+ *
+ * vi: set shiftwidth=8 tabstop=8 noexpandtab:
+ * :indentSize=8:tabSize=8:noTabs=false:
+ */