Fix RFC number.

Use "tvb_reported_length_remaining()" for all length checks and values,
so we get the *actual* packet length, not the *captured* packet length
(it's a *feature* if it reports a "packet cut short" error if the packet
really *was* cut short by slicing).

Set subtree lengths to -1, so that if an exception is throws while
dissecting them, the length includes all the data.

Get rid of unused variables, and mark unused parameters.

In heuristic checks, give up if we don't have enough data to check.

svn path=/trunk/; revision=16599

1 files changed, 28 insertions, 26 deletions

diff --git a/epan/dissectors/packet-rmt-norm.c b/epan/dissectors/packet-rmt-norm.c
index 1856756e39..afd19896ff 100644
--- a/epan/dissectors/packet-rmt-norm.c
+++ b/epan/dissectors/packet-rmt-norm.c
@@ -16,7 +16,7 @@
  * coordination among senders and receivers.
  *
  * References:
- *     RFC 3490, Negative-acknowledgment (NACK)-Oriented Reliable Multicast (NORM) Protocol
+ *     RFC 3940, Negative-acknowledgment (NACK)-Oriented Reliable Multicast (NORM) Protocol
  *
  * $Id$
  *
@@ -188,7 +188,8 @@ static guint dissect_feccode(struct _norm *norm, struct _fec_ptr *f, proto_tree
 	}
 	proto_tree_add_item(tree, hf.object_transport_id, tvb, offset, 2, FALSE); offset+=2;
 
-	if (norm->fec.encoding_id_present && tvb_length(tvb) > offset) {
+	if (norm->fec.encoding_id_present &&
+	    tvb_reported_length_remaining(tvb, offset) > 0) {
 		fec_dissector(*f, tvb, tree, &offset);
 		if (check_col(pinfo->cinfo, COL_INFO))
 			fec_info_column(f->fec, pinfo);
@@ -197,7 +198,7 @@ static guint dissect_feccode(struct _norm *norm, struct _fec_ptr *f, proto_tree
 }
 
 static guint dissect_norm_hdrext(struct _norm *norm, struct _fec_ptr *f, proto_tree *tree,
-							 tvbuff_t *tvb, guint offset, packet_info *pinfo)
+							 tvbuff_t *tvb, guint offset, packet_info *pinfo _U_)
 {
 	guint i;
 	proto_item *ti;
@@ -241,9 +242,8 @@ static guint dissect_nack_data(struct _norm *norm, proto_tree *tree,
 {
 	proto_item *ti, *tif;
 	proto_tree *nack_tree, *flag_tree;
-	guint orig_offset = offset;
 	guint16 len;
-	ti = proto_tree_add_text(tree, tvb, offset, 8, "NACK Data");
+	ti = proto_tree_add_text(tree, tvb, offset, -1, "NACK Data");
 	nack_tree = proto_item_add_subtree(ti, ett.nackdata);
 	proto_tree_add_item(nack_tree, hf.nack_form, tvb, offset, 1, FALSE); offset += 1;
 
@@ -303,14 +303,14 @@ static void dissect_norm_data(struct _norm *norm, proto_tree *tree,
 		proto_tree_add_item(flag_tree, hf.payload_offset, tvb, offset, 4, FALSE); offset+=4;
 
 	}
-	if (tvb_length(tvb) > offset)
-		proto_tree_add_none_format(tree, hf.payload, tvb, offset, -1, "Payload (%u bytes)", tvb_length(tvb) - offset);
+	if (tvb_reported_length_remaining(tvb, offset) > 0)
+		proto_tree_add_none_format(tree, hf.payload, tvb, offset, -1, "Payload (%u bytes)", tvb_reported_length_remaining(tvb, offset));
 
 }
 
 /* code to dissect NORM info packets */
 static void dissect_norm_info(struct _norm *norm, proto_tree *tree,
-	tvbuff_t *tvb, guint offset, packet_info *pinfo)
+	tvbuff_t *tvb, guint offset, packet_info *pinfo _U_)
 {
 	guint8 flags;
 	proto_item *ti;
@@ -344,8 +344,8 @@ static void dissect_norm_info(struct _norm *norm, proto_tree *tree,
 		f.prefs = &preferences.fec;
 		offset = dissect_norm_hdrext(norm, &f, tree, tvb, offset, pinfo);
 	}
-	if (tvb_length(tvb) > offset)
-		proto_tree_add_none_format(tree, hf.payload, tvb, offset, -1, "Payload (%u bytes)", tvb_length(tvb) - offset);
+	if (tvb_reported_length_remaining(tvb, offset) > 0)
+		proto_tree_add_none_format(tree, hf.payload, tvb, offset, -1, "Payload (%u bytes)", tvb_reported_length_remaining(tvb, offset));
 
 }
 /* code to dissect NORM cmd(flush) packets */
@@ -376,7 +376,7 @@ static guint dissect_norm_cmd_repairadv(struct _norm *norm, proto_tree *tree,
 		f.prefs = &preferences.fec;
 		offset = dissect_norm_hdrext(norm, &f, tree, tvb, offset, pinfo);
 	}
-	while (offset < tvb_length(tvb)) {
+	while (tvb_reported_length_remaining(tvb, offset) > 0) {
 		offset = dissect_nack_data(norm, tree, tvb, offset, pinfo);
 	}
 	return offset;
@@ -384,7 +384,7 @@ static guint dissect_norm_cmd_repairadv(struct _norm *norm, proto_tree *tree,
 
 /* code to dissect NORM cmd(cc) packets */
 static guint dissect_norm_cmd_cc(struct _norm *norm, proto_tree *tree,
-	tvbuff_t *tvb, guint offset, packet_info *pinfo)
+	tvbuff_t *tvb, guint offset, packet_info *pinfo _U_)
 {
 	proto_tree_add_item(tree, hf.reserved, tvb, offset, 1, FALSE); offset ++;
 	proto_tree_add_item(tree, hf.cc_sequence, tvb, offset, 2, FALSE); offset += 2;
@@ -400,7 +400,7 @@ static guint dissect_norm_cmd_cc(struct _norm *norm, proto_tree *tree,
 		f.prefs = &preferences.fec;
 		offset = dissect_norm_hdrext(norm, &f, tree, tvb, offset, pinfo);
 	}
-	while (offset + 8 <= tvb_length(tvb)) {
+	while (tvb_reported_length_remaining(tvb, offset) > 0) {
 		proto_item *ti, *tif;
 		proto_tree *cc_tree, *flag_tree;
 		double grtt;
@@ -430,15 +430,15 @@ static guint dissect_norm_cmd_squelch(struct _norm *norm, proto_tree *tree,
 	struct _fec_ptr f;
 	offset = dissect_feccode(norm, &f, tree, tvb, offset, pinfo, 0);
 
-	while (offset + 2 <= tvb_length(tvb)) {
+	while (tvb_reported_length_remaining(tvb, offset) > 0) {
 		proto_tree_add_item(tree, hf.cc_transport_id, tvb, offset, 4, FALSE); offset += 2;
 	}
 	return offset;
 }
 
 /* code to dissect NORM cmd(squelch) packets */
-static guint dissect_norm_cmd_ackreq(struct _norm *norm, proto_tree *tree,
-	tvbuff_t *tvb, guint offset, packet_info *pinfo)
+static guint dissect_norm_cmd_ackreq(struct _norm *norm _U_, proto_tree *tree,
+	tvbuff_t *tvb, guint offset, packet_info *pinfo _U_)
 {
 	proto_tree_add_item(tree, hf.reserved, tvb, offset, 1, FALSE); offset ++;
 	proto_tree_add_item(tree, hf.ack_type, tvb, offset, 1, FALSE); offset += 1;
@@ -475,8 +475,8 @@ static void dissect_norm_cmd(struct _norm *norm, proto_tree *tree,
 		offset = dissect_norm_cmd_ackreq(norm, tree, tvb, offset, pinfo);
 		break;
 	}
-	if (tvb_length(tvb) > offset)
-		proto_tree_add_none_format(tree, hf.payload, tvb, offset, -1, "Payload (%u bytes)", tvb_length(tvb) - offset);
+	if (tvb_reported_length_remaining(tvb, offset) > 0)
+		proto_tree_add_none_format(tree, hf.payload, tvb, offset, -1, "Payload (%u bytes)", tvb_reported_length_remaining(tvb, offset));
 }
 
 /* code to dissect NORM ack packets */
@@ -505,8 +505,8 @@ static void dissect_norm_ack(struct _norm *norm, proto_tree *tree,
 		offset = dissect_norm_hdrext(norm, &f, tree, tvb, offset, pinfo);
 	}
 
-	if (tvb_length(tvb) > offset)
-		proto_tree_add_none_format(tree, hf.payload, tvb, offset, -1, "Payload (%u bytes)", tvb_length(tvb) - offset);
+	if (tvb_reported_length_remaining(tvb, offset) > 0)
+		proto_tree_add_none_format(tree, hf.payload, tvb, offset, -1, "Payload (%u bytes)", tvb_reported_length_remaining(tvb, offset));
 
 }
 
@@ -531,11 +531,11 @@ static void dissect_norm_nack(struct _norm *norm, proto_tree *tree,
 		offset = dissect_norm_hdrext(norm, &f, tree, tvb, offset, pinfo);
 	}
 
-	while (offset < tvb_length(tvb)) {
+	while (tvb_reported_length_remaining(tvb, offset) > 0) {
 		offset = dissect_nack_data(norm, tree, tvb, offset, pinfo);
 	}
-	if (tvb_length(tvb) > offset)
-		proto_tree_add_none_format(tree, hf.payload, tvb, offset, -1, "Payload (%u bytes)", tvb_length(tvb) - offset);
+	if (tvb_reported_length_remaining(tvb, offset) > 0)
+		proto_tree_add_none_format(tree, hf.payload, tvb, offset, -1, "Payload (%u bytes)", tvb_reported_length_remaining(tvb, offset));
 
 }
 /* Code to actually dissect the packets */
@@ -632,8 +632,8 @@ static void dissect_norm(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 			break;
 		default:
 			/* Add the Payload item */
-			if (tvb_length(tvb) > offset)
-				proto_tree_add_none_format(norm_tree, hf.payload, tvb, offset, -1, "Payload (%u bytes)", tvb_length(tvb) - offset);
+			if (tvb_reported_length_remaining(tvb, offset) > 0)
+				proto_tree_add_none_format(norm_tree, hf.payload, tvb, offset, -1, "Payload (%u bytes)", tvb_reported_length_remaining(tvb, offset));
 			break;
 		}
 
@@ -654,6 +654,8 @@ dissect_norm_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 	guint8 byte1;
 	if (!global_norm_heur)
 		return FALSE;
+	if (!tvb_bytes_exist(tvb, 0, 2))
+		return FALSE;	/* not enough to check */
 	byte1 = tvb_get_guint8(tvb, 0);
 
 	if (hi_nibble(byte1) != 1) return FALSE;
@@ -662,7 +664,7 @@ dissect_norm_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 	if (tvb_length_remaining(tvb, 0) < 12)
 		return FALSE;
 	dissect_norm(tvb, pinfo, tree);
-    return TRUE; /* could be a NORM packet */
+	return TRUE; /* appears to be a NORM packet */
 }
 
 void proto_reg_handoff_norm(void)