Tvbuffify the DNS, NBNS, NBDS, and NBSS dissectors.

Add a "tvb_memeql()" routine, for doing "memcmp()"-style equality
comparisons.

svn path=/trunk/; revision=3631

1 files changed, 319 insertions, 443 deletions

diff --git a/packet-nbns.c b/packet-nbns.c
index 763828e9ea..86fa3ca743 100644
--- a/packet-nbns.c
+++ b/packet-nbns.c
@@ -4,12 +4,11 @@
  * Gilbert Ramirez <gram@xiexie.org>
  * Much stuff added by Guy Harris <guy@alum.mit.edu>
  *
- * $Id: packet-nbns.c,v 1.52 2001/06/18 02:17:49 guy Exp $
+ * $Id: packet-nbns.c,v 1.53 2001/07/02 07:11:39 guy Exp $
  *
  * Ethereal - Network traffic analyzer
- * By Gerald Combs <gerald@zing.org>
+ * By Gerald Combs <gerald@ethereal.com>
  * 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
@@ -197,7 +196,7 @@ nbns_type_name (int type)
 #define NBNAME_BUF_LEN 128
 
 static int
-get_nbns_name(const u_char *pd, int offset, int nbns_data_offset,
+get_nbns_name(tvbuff_t *tvb, int offset, int nbns_data_offset,
     char *name_ret, int *name_type_ret)
 {
 	int name_len;
@@ -206,7 +205,7 @@ get_nbns_name(const u_char *pd, int offset, int nbns_data_offset,
 	char *pname, *pnbname, cname, cnbname;
 	int name_type;
 
-	name_len = get_dns_name(pd, offset, nbns_data_offset, name,
+	name_len = get_dns_name(tvb, offset, nbns_data_offset, name,
 	    sizeof(name));
 
 	/* OK, now undo the first-level encoding. */
@@ -290,7 +289,7 @@ bad:
 
 
 static int
-get_nbns_name_type_class(const u_char *pd, int offset, int nbns_data_offset,
+get_nbns_name_type_class(tvbuff_t *tvb, int offset, int nbns_data_offset,
     char *name_ret, int *name_len_ret, int *name_type_ret, int *type_ret,
     int *class_ret)
 {
@@ -298,22 +297,14 @@ get_nbns_name_type_class(const u_char *pd, int offset, int nbns_data_offset,
 	int type;
 	int class;
 
-	name_len = get_nbns_name(pd, offset, nbns_data_offset, name_ret,
+	name_len = get_nbns_name(tvb, offset, nbns_data_offset, name_ret,
 	   name_type_ret);
 	offset += name_len;
 	
-	if (!BYTES_ARE_IN_FRAME(offset, 2)) {
-		/* We ran past the end of the captured data in the packet. */
-		return -1;
-	}
-	type = pntohs(&pd[offset]);
+	type = tvb_get_ntohs(tvb, offset);
 	offset += 2;
 
-	if (!BYTES_ARE_IN_FRAME(offset, 2)) {
-		/* We ran past the end of the captured data in the packet. */
-		return -1;
-	}
-	class = pntohs(&pd[offset]);
+	class = tvb_get_ntohs(tvb, offset);
 
 	*type_ret = type;
 	*class_ret = class;
@@ -323,20 +314,20 @@ get_nbns_name_type_class(const u_char *pd, int offset, int nbns_data_offset,
 }
 
 static void
-add_name_and_type(proto_tree *tree, int offset, int len, char *tag,
-    char *name, int name_type)
+add_name_and_type(proto_tree *tree, tvbuff_t *tvb, int offset, int len,
+    char *tag, char *name, int name_type)
 {
 	if (name_type != -1) {
-		proto_tree_add_text(tree, NullTVB, offset, len, "%s: %s (%s)",
+		proto_tree_add_text(tree, tvb, offset, len, "%s: %s (%s)",
 		    tag, name, netbios_name_type_descr(name_type));
 	} else {
-		proto_tree_add_text(tree, NullTVB, offset, len, "%s: %s",
+		proto_tree_add_text(tree, tvb, offset, len, "%s: %s",
 		    tag, name);
 	}
 }
 
 static int
-dissect_nbns_query(const u_char *pd, int offset, int nbns_data_offset,
+dissect_nbns_query(tvbuff_t *tvb, int offset, int nbns_data_offset,
     frame_data *fd, proto_tree *nbns_tree)
 {
 	int len;
@@ -347,20 +338,16 @@ dissect_nbns_query(const u_char *pd, int offset, int nbns_data_offset,
 	int class;
 	char *class_name;
 	char *type_name;
-	const u_char *dptr;
-	const u_char *data_start;
+	int data_offset;
+	int data_start;
 	proto_tree *q_tree;
 	proto_item *tq;
 
-	data_start = dptr = pd + offset;
+	data_start = data_offset = offset;
 
-	len = get_nbns_name_type_class(pd, offset, nbns_data_offset, name,
+	len = get_nbns_name_type_class(tvb, offset, nbns_data_offset, name,
 	    &name_len, &name_type, &type, &class);
-	if (len < 0) {
-		/* We ran past the end of the data in the packet. */
-		return 0;
-	}
-	dptr += len;
+	data_offset += len;
 
 	type_name = nbns_type_name(type);
 	class_name = dns_class_name(class);
@@ -368,27 +355,27 @@ dissect_nbns_query(const u_char *pd, int offset, int nbns_data_offset,
 	if (fd != NULL)
 		col_append_fstr(fd, COL_INFO, " %s %s", type_name, name);
 	if (nbns_tree != NULL) {
-		tq = proto_tree_add_text(nbns_tree, NullTVB, offset, len,
+		tq = proto_tree_add_text(nbns_tree, tvb, offset, len,
 		    "%s: type %s, class %s",  name, type_name, class_name);
 		q_tree = proto_item_add_subtree(tq, ett_nbns_qd);
 
-		add_name_and_type(q_tree, offset, name_len, "Name", name,
+		add_name_and_type(q_tree, tvb, offset, name_len, "Name", name,
 		    name_type);
 		offset += name_len;
 
-		proto_tree_add_text(q_tree, NullTVB, offset, 2, "Type: %s", type_name);
+		proto_tree_add_text(q_tree, tvb, offset, 2, "Type: %s", type_name);
 		offset += 2;
 
-		proto_tree_add_text(q_tree, NullTVB, offset, 2, "Class: %s", class_name);
+		proto_tree_add_text(q_tree, tvb, offset, 2, "Class: %s", class_name);
 		offset += 2;
 	}
 	
-	return dptr - data_start;
+	return data_offset - data_start;
 }
 
 static void
-nbns_add_nbns_flags(proto_tree *nbns_tree, int offset, u_short flags,
-    int is_wack)
+nbns_add_nbns_flags(proto_tree *nbns_tree, tvbuff_t *tvb, int offset,
+    u_short flags, int is_wack)
 {
 	char buf[128+1];
 	proto_tree *field_tree;
@@ -413,48 +400,48 @@ nbns_add_nbns_flags(proto_tree *nbns_tree, int offset, u_short flags,
 		strcat(buf, val_to_str(flags & F_RCODE, rcode_vals,
 		    "Unknown error"));
 	}
-	tf = proto_tree_add_text(nbns_tree, NullTVB, offset, 2,
+	tf = proto_tree_add_text(nbns_tree, tvb, offset, 2,
 			"Flags: 0x%04x (%s)", flags, buf);
 	field_tree = proto_item_add_subtree(tf, ett_nbns_flags);
-	proto_tree_add_text(field_tree, NullTVB, offset, 2, "%s",
+	proto_tree_add_text(field_tree, tvb, offset, 2, "%s",
 			decode_boolean_bitfield(flags, F_RESPONSE,
 				2*8, "Response", "Query"));
-	proto_tree_add_text(field_tree, NullTVB, offset, 2, "%s",
+	proto_tree_add_text(field_tree, tvb, offset, 2, "%s",
 			decode_enumerated_bitfield(flags, F_OPCODE,
 				2*8, opcode_vals, "%s"));
 	if (flags & F_RESPONSE) {
-		proto_tree_add_text(field_tree, NullTVB, offset, 2,
+		proto_tree_add_text(field_tree, tvb, offset, 2,
 			"%s",
 			decode_boolean_bitfield(flags, F_AUTHORITATIVE,
 				2*8,
 				"Server is an authority for domain",
 				"Server isn't an authority for domain"));
 	}
-	proto_tree_add_text(field_tree, NullTVB, offset, 2, "%s",
+	proto_tree_add_text(field_tree, tvb, offset, 2, "%s",
 			decode_boolean_bitfield(flags, F_TRUNCATED,
 				2*8,
 				"Message is truncated",
 				"Message is not truncated"));
-	proto_tree_add_text(field_tree, NullTVB, offset, 2, "%s",
+	proto_tree_add_text(field_tree, tvb, offset, 2, "%s",
 			decode_boolean_bitfield(flags, F_RECDESIRED,
 				2*8,
 				"Do query recursively",
 				"Don't do query recursively"));
 	if (flags & F_RESPONSE) {
-		proto_tree_add_text(field_tree, NullTVB, offset, 2,
+		proto_tree_add_text(field_tree, tvb, offset, 2,
 			"%s",
 			decode_boolean_bitfield(flags, F_RECAVAIL,
 				2*8,
 				"Server can do recursive queries",
 				"Server can't do recursive queries"));
 	}
-	proto_tree_add_text(field_tree, NullTVB, offset, 2, "%s",
+	proto_tree_add_text(field_tree, tvb, offset, 2, "%s",
 			decode_boolean_bitfield(flags, F_BROADCAST,
 				2*8,
 				"Broadcast packet",
 				"Not a broadcast packet"));
 	if (flags & F_RESPONSE && !is_wack) {
-		proto_tree_add_text(field_tree, NullTVB, offset, 2,
+		proto_tree_add_text(field_tree, tvb, offset, 2,
 			"%s",
 			decode_enumerated_bitfield(flags, F_RCODE,
 				2*8,
@@ -463,7 +450,7 @@ nbns_add_nbns_flags(proto_tree *nbns_tree, int offset, u_short flags,
 }
 
 static void
-nbns_add_nb_flags(proto_tree *rr_tree, int offset, u_short flags)
+nbns_add_nb_flags(proto_tree *rr_tree, tvbuff_t *tvb, int offset, u_short flags)
 {
 	char buf[128+1];
 	proto_tree *field_tree;
@@ -483,21 +470,22 @@ nbns_add_nb_flags(proto_tree *rr_tree, int offset, u_short flags)
 		strcat(buf, "group");
 	else
 		strcat(buf, "unique");
-	tf = proto_tree_add_text(rr_tree, NullTVB, offset, 2, "Flags: 0x%x (%s)", flags,
+	tf = proto_tree_add_text(rr_tree, tvb, offset, 2, "Flags: 0x%x (%s)", flags,
 			buf);
 	field_tree = proto_item_add_subtree(tf, ett_nbns_nb_flags);
-	proto_tree_add_text(field_tree, NullTVB, offset, 2, "%s",
+	proto_tree_add_text(field_tree, tvb, offset, 2, "%s",
 			decode_boolean_bitfield(flags, NB_FLAGS_G,
 				2*8,
 				"Group name",
 				"Unique name"));
-	proto_tree_add_text(field_tree, NullTVB, offset, 2, "%s",
+	proto_tree_add_text(field_tree, tvb, offset, 2, "%s",
 			decode_enumerated_bitfield(flags, NB_FLAGS_ONT,
 				2*8, nb_flags_ont_vals, "%s"));
 }
 
 static void
-nbns_add_name_flags(proto_tree *rr_tree, int offset, u_short flags)
+nbns_add_name_flags(proto_tree *rr_tree, tvbuff_t *tvb, int offset,
+    u_short flags)
 {
 	char buf[128+1];
 	proto_item *field_tree;
@@ -524,33 +512,33 @@ nbns_add_name_flags(proto_tree *rr_tree, int offset, u_short flags)
 		strcat(buf, ", active");
 	if (flags & NAME_FLAGS_PRM)
 		strcat(buf, ", permanent node name");
-	tf = proto_tree_add_text(rr_tree, NullTVB, offset, 2, "Name flags: 0x%x (%s)",
+	tf = proto_tree_add_text(rr_tree, tvb, offset, 2, "Name flags: 0x%x (%s)",
 			flags, buf);
 	field_tree = proto_item_add_subtree(tf, ett_nbns_name_flags);
-	proto_tree_add_text(field_tree, NullTVB, offset, 2, "%s",
+	proto_tree_add_text(field_tree, tvb, offset, 2, "%s",
 			decode_boolean_bitfield(flags, NAME_FLAGS_G,
 				2*8,
 				"Group name",
 				"Unique name"));
-	proto_tree_add_text(field_tree, NullTVB, offset, 2, "%s",
+	proto_tree_add_text(field_tree, tvb, offset, 2, "%s",
 			decode_enumerated_bitfield(flags, NAME_FLAGS_ONT,
 				2*8, name_flags_ont_vals, "%s"));
-	proto_tree_add_text(field_tree, NullTVB, offset, 2, "%s",
+	proto_tree_add_text(field_tree, tvb, offset, 2, "%s",
 			decode_boolean_bitfield(flags, NAME_FLAGS_DRG,
 				2*8,
 				"Name is being deregistered",
 				"Name is not being deregistered"));
-	proto_tree_add_text(field_tree, NullTVB, offset, 2, "%s",
+	proto_tree_add_text(field_tree, tvb, offset, 2, "%s",
 			decode_boolean_bitfield(flags, NAME_FLAGS_CNF,
 				2*8,
 				"Name is in conflict",
 				"Name is not in conflict"));
-	proto_tree_add_text(field_tree, NullTVB, offset, 2, "%s",
+	proto_tree_add_text(field_tree, tvb, offset, 2, "%s",
 			decode_boolean_bitfield(flags, NAME_FLAGS_ACT,
 				2*8,
 				"Name is active",
 				"Name is not active"));
-	proto_tree_add_text(field_tree, NullTVB, offset, 2, "%s",
+	proto_tree_add_text(field_tree, tvb, offset, 2, "%s",
 			decode_boolean_bitfield(flags, NAME_FLAGS_PRM,
 				2*8,
 				"Permanent node name",
@@ -558,7 +546,7 @@ nbns_add_name_flags(proto_tree *rr_tree, int offset, u_short flags)
 }
 
 static int
-dissect_nbns_answer(const u_char *pd, int offset, int nbns_data_offset,
+dissect_nbns_answer(tvbuff_t *tvb, int offset, int nbns_data_offset,
     frame_data *fd, proto_tree *nbns_tree, int opcode)
 {
 	int len;
@@ -569,9 +557,9 @@ dissect_nbns_answer(const u_char *pd, int offset, int nbns_data_offset,
 	int class;
 	char *class_name;
 	char *type_name;
-	const u_char *dptr;
+	int data_offset;
 	int cur_offset;
-	const u_char *data_start;
+	int data_start;
 	u_int ttl;
 	u_short data_len;
 	u_short flags;
@@ -582,35 +570,23 @@ dissect_nbns_answer(const u_char *pd, int offset, int nbns_data_offset,
 	char nbname[16+4+1];	/* 4 for [<last char>] */
 	u_short name_flags;
 
-	data_start = dptr = pd + offset;
+	data_start = data_offset = offset;
 	cur_offset = offset;
 
-	len = get_nbns_name_type_class(pd, offset, nbns_data_offset, name,
+	len = get_nbns_name_type_class(tvb, offset, nbns_data_offset, name,
 	    &name_len, &name_type, &type, &class);
-	if (len < 0) {
-		/* We ran past the end of the data in the packet. */
-		return 0;
-	}
-	dptr += len;
+	data_offset += len;
 	cur_offset += len;
 
 	type_name = nbns_type_name(type);
 	class_name = dns_class_name(class);
 
-	if (!BYTES_ARE_IN_FRAME(cur_offset, 4)) {
-		/* We ran past the end of the captured data in the packet. */
-		return 0;
-	}
-	ttl = pntohl(dptr);
-	dptr += 4;
+	ttl = tvb_get_ntohl(tvb, data_offset);
+	data_offset += 4;
 	cur_offset += 4;
 
-	if (!BYTES_ARE_IN_FRAME(cur_offset, 2)) {
-		/* We ran past the end of the captured data in the packet. */
-		return 0;
-	}
-	data_len = pntohs(dptr);
-	dptr += 2;
+	data_len = tvb_get_ntohs(tvb, data_offset);
+	data_offset += 2;
 	cur_offset += 2;
 
 	switch (type) {
@@ -618,72 +594,56 @@ dissect_nbns_answer(const u_char *pd, int offset, int nbns_data_offset,
 		if (fd != NULL) {
 			if (opcode != OPCODE_WACK) {
 				col_append_fstr(fd, COL_INFO, " %s %s",
-				    type_name, ip_to_str((guint8 *)(dptr + 2)));
+				    type_name,
+				    ip_to_str(tvb_get_ptr(tvb, data_offset+2, 4)));
 			}
 		}
 		if (nbns_tree == NULL)
 			break;
-		trr = proto_tree_add_text(nbns_tree, NullTVB, offset,
-		    (dptr - data_start) + data_len,
+		trr = proto_tree_add_text(nbns_tree, tvb, offset,
+		    (data_offset - data_start) + data_len,
 		    "%s: type %s, class %s",
 		    name, type_name, class_name);
 		strcat(name, " (");
 		strcat(name, netbios_name_type_descr(name_type));
 		strcat(name, ")");
-		rr_tree = add_rr_to_tree(trr, ett_nbns_rr, offset, name,
+		rr_tree = add_rr_to_tree(trr, ett_nbns_rr, tvb, offset, name,
 		    name_len, type_name, class_name, ttl, data_len);
 		while (data_len > 0) {
 			if (opcode == OPCODE_WACK) {
 				/* WACK response.  This doesn't contain the
 				 * same type of RR data as other T_NB
 				 * responses.  */
-				if (!BYTES_ARE_IN_FRAME(cur_offset, 2)) {
-					/* We ran past the end of the captured
-					   data in the packet. */
-					return 0;
-				}
 				if (data_len < 2) {
-					proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+					proto_tree_add_text(rr_tree, tvb, cur_offset,
 					    data_len, "(incomplete entry)");
 					break;
 				}
-				flags = pntohs(dptr);
-				dptr += 2;
-				nbns_add_nbns_flags(rr_tree, cur_offset,
+				flags = tvb_get_ntohs(tvb, cur_offset);
+				nbns_add_nbns_flags(rr_tree, tvb, cur_offset,
 				    flags, 1);
 				cur_offset += 2;
 				data_len -= 2;
 			} else {
-				if (!BYTES_ARE_IN_FRAME(cur_offset, 2)) {
-					/* We ran past the end of the captured
-					   data in the packet. */
-					return 0;
-				}
 				if (data_len < 2) {
-					proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+					proto_tree_add_text(rr_tree, tvb, cur_offset,
 					    data_len, "(incomplete entry)");
 					break;
 				}
-				flags = pntohs(dptr);
-				dptr += 2;
-				nbns_add_nb_flags(rr_tree, cur_offset, flags);
+				flags = tvb_get_ntohs(tvb, cur_offset);
+				nbns_add_nb_flags(rr_tree, tvb, cur_offset,
+				    flags);
 				cur_offset += 2;
 				data_len -= 2;
 
-				if (!BYTES_ARE_IN_FRAME(cur_offset, 4)) {
-					/* We ran past the end of the captured
-					   data in the packet. */
-					return 0;
-				}
 				if (data_len < 4) {
-					proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+					proto_tree_add_text(rr_tree, tvb, cur_offset,
 					    data_len, "(incomplete entry)");
 					break;
 				}
-				proto_tree_add_text(rr_tree, NullTVB, cur_offset, 4,
+				proto_tree_add_text(rr_tree, tvb, cur_offset, 4,
 				    "Addr: %s",
-				    ip_to_str((guint8 *)dptr));
-				dptr += 4;
+				    ip_to_str(tvb_get_ptr(tvb, cur_offset, 4)));
 				cur_offset += 4;
 				data_len -= 4;
 			}
@@ -695,354 +655,240 @@ dissect_nbns_answer(const u_char *pd, int offset, int nbns_data_offset,
 			col_append_fstr(fd, COL_INFO, " %s", type_name);
 		if (nbns_tree == NULL)
 			break;
-		trr = proto_tree_add_text(nbns_tree, NullTVB, offset,
-		    (dptr - data_start) + data_len,
+		trr = proto_tree_add_text(nbns_tree, tvb, offset,
+		    (data_offset - data_start) + data_len,
 		    "%s: type %s, class %s",
 		    name, type_name, class_name);
-		rr_tree = add_rr_to_tree(trr, ett_nbns_rr, offset, name,
+		rr_tree = add_rr_to_tree(trr, ett_nbns_rr, tvb, offset, name,
 		    name_len, type_name, class_name, ttl, data_len);
-		if (!BYTES_ARE_IN_FRAME(cur_offset, 1)) {
-			/* We ran past the end of the captured
-			   data in the packet. */
-			return 0;
-		}
 		if (data_len < 1) {
-			proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+			proto_tree_add_text(rr_tree, tvb, cur_offset,
 			    data_len, "(incomplete entry)");
 			break;
 		}
-		num_names = *dptr;
-		dptr += 1;
-		proto_tree_add_text(rr_tree, NullTVB, cur_offset, 2,
+		num_names = tvb_get_guint8(tvb, cur_offset);
+		proto_tree_add_text(rr_tree, tvb, cur_offset, 1,
 		    "Number of names: %u", num_names);
 		cur_offset += 1;
 
 		while (num_names != 0) {
-			if (!BYTES_ARE_IN_FRAME(cur_offset, NETBIOS_NAME_LEN)) {
-				/* We ran past the end of the captured
-				   data in the packet. */
-				return 0;
-			}
 			if (data_len < NETBIOS_NAME_LEN) {
-				proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+				proto_tree_add_text(rr_tree, tvb, cur_offset,
 				    data_len, "(incomplete entry)");
 				goto out;
 			}
-			memcpy(nbname, dptr, NETBIOS_NAME_LEN);
-			dptr += NETBIOS_NAME_LEN;
+			tvb_memcpy(tvb, (guint8 *)nbname, cur_offset,
+			    NETBIOS_NAME_LEN);
 			name_type = process_netbios_name(nbname,
 			    name_str);
-			proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+			proto_tree_add_text(rr_tree, tvb, cur_offset,
 			    NETBIOS_NAME_LEN, "Name: %s<%02x> (%s)",
 			    name_str, name_type,
 			    netbios_name_type_descr(name_type));
 			cur_offset += NETBIOS_NAME_LEN;
 			data_len -= NETBIOS_NAME_LEN;
 
-			if (!BYTES_ARE_IN_FRAME(cur_offset, 2)) {
-				/* We ran past the end of the captured
-				   data in the packet. */
-				return 0;
-			}
 			if (data_len < 2) {
-				proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+				proto_tree_add_text(rr_tree, tvb, cur_offset,
 				    data_len, "(incomplete entry)");
 				goto out;
 			}
-			name_flags = pntohs(dptr);
-			dptr += 2;
-			nbns_add_name_flags(rr_tree, cur_offset, name_flags);
+			name_flags = tvb_get_ntohs(tvb, cur_offset);
+			nbns_add_name_flags(rr_tree, tvb, cur_offset,
+			    name_flags);
 			cur_offset += 2;
 			data_len -= 2;
 
 			num_names--;
 		}
 
-		if (!BYTES_ARE_IN_FRAME(cur_offset, 6)) {
-			/* We ran past the end of the captured
-			   data in the packet. */
-			return 0;
-		}
 		if (data_len < 6) {
-			proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+			proto_tree_add_text(rr_tree, tvb, cur_offset,
 			    data_len, "(incomplete entry)");
 			break;
 		}
-		proto_tree_add_text(rr_tree, NullTVB, cur_offset, 6,
+		proto_tree_add_text(rr_tree, tvb, cur_offset, 6,
 		    "Unit ID: %s",
-		    ether_to_str((guint8 *)dptr));
-		dptr += 6;
+		    ether_to_str(tvb_get_ptr(tvb, cur_offset, 6)));
 		cur_offset += 6;
 		data_len -= 6;
 
-		if (!BYTES_ARE_IN_FRAME(cur_offset, 1)) {
-			/* We ran past the end of the captured
-			   data in the packet. */
-			return 0;
-		}
 		if (data_len < 1) {
-			proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+			proto_tree_add_text(rr_tree, tvb, cur_offset,
 			    data_len, "(incomplete entry)");
 			break;
 		}
-		proto_tree_add_text(rr_tree, NullTVB, cur_offset, 1,
-		    "Jumpers: 0x%x", *dptr);
-		dptr += 1;
+		proto_tree_add_text(rr_tree, tvb, cur_offset, 1,
+		    "Jumpers: 0x%x", tvb_get_guint8(tvb, cur_offset));
 		cur_offset += 1;
 		data_len -= 1;
 
-		if (!BYTES_ARE_IN_FRAME(cur_offset, 1)) {
-			/* We ran past the end of the captured
-			   data in the packet. */
-			return 0;
-		}
 		if (data_len < 1) {
-			proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+			proto_tree_add_text(rr_tree, tvb, cur_offset,
 			    data_len, "(incomplete entry)");
 			break;
 		}
-		proto_tree_add_text(rr_tree, NullTVB, cur_offset, 1,
-		    "Test result: 0x%x", *dptr);
-		dptr += 1;
+		proto_tree_add_text(rr_tree, tvb, cur_offset, 1,
+		    "Test result: 0x%x", tvb_get_guint8(tvb, cur_offset));
 		cur_offset += 1;
 		data_len -= 1;
 
-		if (!BYTES_ARE_IN_FRAME(cur_offset, 2)) {
-			/* We ran past the end of the captured
-			   data in the packet. */
-			return 0;
-		}
 		if (data_len < 2) {
-			proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+			proto_tree_add_text(rr_tree, tvb, cur_offset,
 			    data_len, "(incomplete entry)");
 			break;
 		}
-		proto_tree_add_text(rr_tree, NullTVB, cur_offset, 2,
-		    "Version number: 0x%x", pntohs(dptr));
-		dptr += 2;
+		proto_tree_add_text(rr_tree, tvb, cur_offset, 2,
+		    "Version number: 0x%x", tvb_get_ntohs(tvb, cur_offset));
 		cur_offset += 2;
 		data_len -= 2;
 
-		if (!BYTES_ARE_IN_FRAME(cur_offset, 2)) {
-			/* We ran past the end of the captured
-			   data in the packet. */
-			return 0;
-		}
 		if (data_len < 2) {
-			proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+			proto_tree_add_text(rr_tree, tvb, cur_offset,
 			    data_len, "(incomplete entry)");
 			break;
 		}
-		proto_tree_add_text(rr_tree, NullTVB, cur_offset, 2,
-		    "Period of statistics: 0x%x", pntohs(dptr));
-		dptr += 2;
+		proto_tree_add_text(rr_tree, tvb, cur_offset, 2,
+		    "Period of statistics: 0x%x",
+		    tvb_get_ntohs(tvb, cur_offset));
 		cur_offset += 2;
 		data_len -= 2;
 
-		if (!BYTES_ARE_IN_FRAME(cur_offset, 2)) {
-			/* We ran past the end of the captured
-			   data in the packet. */
-			return 0;
-		}
 		if (data_len < 2) {
-			proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+			proto_tree_add_text(rr_tree, tvb, cur_offset,
 			    data_len, "(incomplete entry)");
 			break;
 		}
-		proto_tree_add_text(rr_tree, NullTVB, cur_offset, 2,
-		    "Number of CRCs: %u", pntohs(dptr));
-		dptr += 2;
+		proto_tree_add_text(rr_tree, tvb, cur_offset, 2,
+		    "Number of CRCs: %u", tvb_get_ntohs(tvb, cur_offset));
 		cur_offset += 2;
 		data_len -= 2;
 
-		if (!BYTES_ARE_IN_FRAME(cur_offset, 2)) {
-			/* We ran past the end of the captured
-			   data in the packet. */
-			return 0;
-		}
 		if (data_len < 2) {
-			proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+			proto_tree_add_text(rr_tree, tvb, cur_offset,
 			    data_len, "(incomplete entry)");
 			break;
 		}
-		proto_tree_add_text(rr_tree, NullTVB, cur_offset, 2,
-		    "Number of alignment errors: %u", pntohs(dptr));
-		dptr += 2;
+		proto_tree_add_text(rr_tree, tvb, cur_offset, 2,
+		    "Number of alignment errors: %u",
+		    tvb_get_ntohs(tvb, cur_offset));
 		cur_offset += 2;
 		data_len -= 2;
 
-		if (!BYTES_ARE_IN_FRAME(cur_offset, 2)) {
-			/* We ran past the end of the captured
-			   data in the packet. */
-			return 0;
-		}
 		if (data_len < 2) {
-			proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+			proto_tree_add_text(rr_tree, tvb, cur_offset,
 			    data_len, "(incomplete entry)");
 			break;
 		}
-		proto_tree_add_text(rr_tree, NullTVB, cur_offset, 2,
-		    "Number of collisions: %u", pntohs(dptr));
-		dptr += 2;
+		proto_tree_add_text(rr_tree, tvb, cur_offset, 2,
+		    "Number of collisions: %u", tvb_get_ntohs(tvb, cur_offset));
 		cur_offset += 2;
 		data_len -= 2;
 
-		if (!BYTES_ARE_IN_FRAME(cur_offset, 2)) {
-			/* We ran past the end of the captured
-			   data in the packet. */
-			return 0;
-		}
 		if (data_len < 2) {
-			proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+			proto_tree_add_text(rr_tree, tvb, cur_offset,
 			    data_len, "(incomplete entry)");
 			break;
 		}
-		proto_tree_add_text(rr_tree, NullTVB, cur_offset, 2,
-		    "Number of send aborts: %u", pntohs(dptr));
-		dptr += 2;
+		proto_tree_add_text(rr_tree, tvb, cur_offset, 2,
+		    "Number of send aborts: %u", tvb_get_ntohs(tvb, cur_offset));
 		cur_offset += 2;
 		data_len -= 2;
 
-		if (!BYTES_ARE_IN_FRAME(cur_offset, 4)) {
-			/* We ran past the end of the captured
-			   data in the packet. */
-			return 0;
-		}
 		if (data_len < 4) {
-			proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+			proto_tree_add_text(rr_tree, tvb, cur_offset,
 			    data_len, "(incomplete entry)");
 			break;
 		}
-		proto_tree_add_text(rr_tree, NullTVB, cur_offset, 4,
-		    "Number of good sends: %u", pntohl(dptr));
-		dptr += 4;
+		proto_tree_add_text(rr_tree, tvb, cur_offset, 4,
+		    "Number of good sends: %u", tvb_get_ntohl(tvb, cur_offset));
 		cur_offset += 4;
 		data_len -= 4;
 
-		if (!BYTES_ARE_IN_FRAME(cur_offset, 4)) {
-			/* We ran past the end of the captured
-			   data in the packet. */
-			return 0;
-		}
 		if (data_len < 4) {
-			proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+			proto_tree_add_text(rr_tree, tvb, cur_offset,
 			    data_len, "(incomplete entry)");
 			break;
 		}
-		proto_tree_add_text(rr_tree, NullTVB, cur_offset, 4,
-		    "Number of good receives: %u", pntohl(dptr));
-		dptr += 4;
+		proto_tree_add_text(rr_tree, tvb, cur_offset, 4,
+		    "Number of good receives: %u",
+		    tvb_get_ntohl(tvb, cur_offset));
 		cur_offset += 4;
 		data_len -= 4;
 
-		if (!BYTES_ARE_IN_FRAME(cur_offset, 2)) {
-			/* We ran past the end of the captured
-			   data in the packet. */
-			return 0;
-		}
 		if (data_len < 2) {
-			proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+			proto_tree_add_text(rr_tree, tvb, cur_offset,
 			    data_len, "(incomplete entry)");
 			break;
 		}
-		proto_tree_add_text(rr_tree, NullTVB, cur_offset, 2,
-		    "Number of retransmits: %u", pntohs(dptr));
-		dptr += 2;
+		proto_tree_add_text(rr_tree, tvb, cur_offset, 2,
+		    "Number of retransmits: %u", tvb_get_ntohs(tvb, cur_offset));
 		cur_offset += 2;
 		data_len -= 2;
 
-		if (!BYTES_ARE_IN_FRAME(cur_offset, 2)) {
-			/* We ran past the end of the captured
-			   data in the packet. */
-			return 0;
-		}
 		if (data_len < 2) {
-			proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+			proto_tree_add_text(rr_tree, tvb, cur_offset,
 			    data_len, "(incomplete entry)");
 			break;
 		}
-		proto_tree_add_text(rr_tree, NullTVB, cur_offset, 2,
-		    "Number of no resource conditions: %u", pntohs(dptr));
-		dptr += 2;
+		proto_tree_add_text(rr_tree, tvb, cur_offset, 2,
+		    "Number of no resource conditions: %u",
+		    tvb_get_ntohs(tvb, cur_offset));
 		cur_offset += 2;
 		data_len -= 2;
 
-		if (!BYTES_ARE_IN_FRAME(cur_offset, 2)) {
-			/* We ran past the end of the captured
-			   data in the packet. */
-			return 0;
-		}
 		if (data_len < 2) {
-			proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+			proto_tree_add_text(rr_tree, tvb, cur_offset,
 			    data_len, "(incomplete entry)");
 			break;
 		}
-		proto_tree_add_text(rr_tree, NullTVB, cur_offset, 2,
-		    "Number of command blocks: %u", pntohs(dptr));
-		dptr += 2;
+		proto_tree_add_text(rr_tree, tvb, cur_offset, 2,
+		    "Number of command blocks: %u",
+		    tvb_get_ntohs(tvb, cur_offset));
 		cur_offset += 2;
 		data_len -= 2;
 
-		if (!BYTES_ARE_IN_FRAME(cur_offset, 2)) {
-			/* We ran past the end of the captured
-			   data in the packet. */
-			return 0;
-		}
 		if (data_len < 2) {
-			proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+			proto_tree_add_text(rr_tree, tvb, cur_offset,
 			    data_len, "(incomplete entry)");
 			break;
 		}
-		proto_tree_add_text(rr_tree, NullTVB, cur_offset, 2,
-		    "Number of pending sessions: %u", pntohs(dptr));
-		dptr += 2;
+		proto_tree_add_text(rr_tree, tvb, cur_offset, 2,
+		    "Number of pending sessions: %u",
+		    tvb_get_ntohs(tvb, cur_offset));
 		cur_offset += 2;
 		data_len -= 2;
 
-		if (!BYTES_ARE_IN_FRAME(cur_offset, 2)) {
-			/* We ran past the end of the captured
-			   data in the packet. */
-			return 0;
-		}
 		if (data_len < 2) {
-			proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+			proto_tree_add_text(rr_tree, tvb, cur_offset,
 			    data_len, "(incomplete entry)");
 			break;
 		}
-		proto_tree_add_text(rr_tree, NullTVB, cur_offset, 2,
-		    "Max number of pending sessions: %u", pntohs(dptr));
-		dptr += 2;
+		proto_tree_add_text(rr_tree, tvb, cur_offset, 2,
+		    "Max number of pending sessions: %u",
+		    tvb_get_ntohs(tvb, cur_offset));
 		cur_offset += 2;
+		data_len -= 2;
 
-		if (!BYTES_ARE_IN_FRAME(cur_offset, 2)) {
-			/* We ran past the end of the captured
-			   data in the packet. */
-			return 0;
-		}
 		if (data_len < 2) {
-			proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+			proto_tree_add_text(rr_tree, tvb, cur_offset,
 			    data_len, "(incomplete entry)");
 			break;
 		}
-		proto_tree_add_text(rr_tree, NullTVB, cur_offset, 2,
-		    "Max total sessions possible: %u", pntohs(dptr));
-		dptr += 2;
+		proto_tree_add_text(rr_tree, tvb, cur_offset, 2,
+		    "Max total sessions possible: %u",
+		    tvb_get_ntohs(tvb, cur_offset));
 		cur_offset += 2;
 		data_len -= 2;
 
-		if (!BYTES_ARE_IN_FRAME(cur_offset, 2)) {
-			/* We ran past the end of the captured
-			   data in the packet. */
-			return 0;
-		}
 		if (data_len < 2) {
-			proto_tree_add_text(rr_tree, NullTVB, cur_offset,
+			proto_tree_add_text(rr_tree, tvb, cur_offset,
 			    data_len, "(incomplete entry)");
 			break;
 		}
-		proto_tree_add_text(rr_tree, NullTVB, cur_offset, 2,
-		    "Session data packet size: %u", pntohs(dptr));
-		dptr += 2;
+		proto_tree_add_text(rr_tree, tvb, cur_offset, 2,
+		    "Session data packet size: %u",
+		    tvb_get_ntohs(tvb, cur_offset));
 		cur_offset += 2;
 		data_len -= 2;
 	out:
@@ -1053,22 +899,22 @@ dissect_nbns_answer(const u_char *pd, int offset, int nbns_data_offset,
 			col_append_fstr(fd, COL_INFO, " %s", type_name);
 		if (nbns_tree == NULL)
 			break;
-		trr = proto_tree_add_text(nbns_tree, NullTVB, offset,
-		    (dptr - data_start) + data_len,
+		trr = proto_tree_add_text(nbns_tree, tvb, offset,
+		    (data_offset - data_start) + data_len,
                     "%s: type %s, class %s",
 		    name, type_name, class_name);
-		rr_tree = add_rr_to_tree(trr, ett_nbns_rr, offset, name,
+		rr_tree = add_rr_to_tree(trr, ett_nbns_rr, tvb, offset, name,
 		    name_len, type_name, class_name, ttl, data_len);
-		proto_tree_add_text(rr_tree, NullTVB, cur_offset, data_len, "Data");
+		proto_tree_add_text(rr_tree, tvb, cur_offset, data_len, "Data");
+		cur_offset += data_len;
 		break;
 	}
-	dptr += data_len;
 	
-	return dptr - data_start;
+	return cur_offset - data_start;
 }
 
 static int
-dissect_query_records(const u_char *pd, int cur_off, int nbns_data_offset,
+dissect_query_records(tvbuff_t *tvb, int cur_off, int nbns_data_offset,
     int count, frame_data *fd, proto_tree *nbns_tree)
 {
 	int start_off, add_off;
@@ -1077,11 +923,11 @@ dissect_query_records(const u_char *pd, int cur_off, int nbns_data_offset,
 	
 	start_off = cur_off;
 	if (nbns_tree != NULL) {
-		ti = proto_tree_add_text(nbns_tree, NullTVB, start_off, 0, "Queries");
+		ti = proto_tree_add_text(nbns_tree, tvb, start_off, 0, "Queries");
 		qatree = proto_item_add_subtree(ti, ett_nbns_qry);
 	}
 	while (count-- > 0) {
-		add_off = dissect_nbns_query(pd, cur_off, nbns_data_offset,
+		add_off = dissect_nbns_query(tvb, cur_off, nbns_data_offset,
 		    fd, qatree);
 		if (add_off <= 0) {
 			/* We ran past the end of the captured data in the
@@ -1099,7 +945,7 @@ dissect_query_records(const u_char *pd, int cur_off, int nbns_data_offset,
 
 
 static int
-dissect_answer_records(const u_char *pd, int cur_off, int nbns_data_offset,
+dissect_answer_records(tvbuff_t *tvb, int cur_off, int nbns_data_offset,
     int count, frame_data *fd, proto_tree *nbns_tree, int opcode, char *name)
 {
 	int start_off, add_off;
@@ -1108,11 +954,11 @@ dissect_answer_records(const u_char *pd, int cur_off, int nbns_data_offset,
 	
 	start_off = cur_off;
 	if (nbns_tree != NULL) {
-		ti = proto_tree_add_text(nbns_tree, NullTVB, start_off, 0, name);
+		ti = proto_tree_add_text(nbns_tree, tvb, start_off, 0, name);
 		qatree = proto_item_add_subtree(ti, ett_nbns_ans);
 	}
 	while (count-- > 0) {
-		add_off = dissect_nbns_answer(pd, cur_off, nbns_data_offset,
+		add_off = dissect_nbns_answer(tvb, cur_off, nbns_data_offset,
 					fd, qatree, opcode);
 		if (add_off <= 0) {
 			/* We ran past the end of the captured data in the
@@ -1127,9 +973,11 @@ dissect_answer_records(const u_char *pd, int cur_off, int nbns_data_offset,
 }
 
 static void
-dissect_nbns(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
+dissect_nbns(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 {
+	int			offset = 0;
 	int			nbns_data_offset;
+	frame_data		*fd;
 	proto_tree		*nbns_tree = NULL;
 	proto_item		*ti;
 	guint16			id, flags, quest, ans, auth, add;
@@ -1137,32 +985,21 @@ dissect_nbns(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
 
 	nbns_data_offset = offset;
 
-	if (check_col(fd, COL_PROTOCOL))
-		col_set_str(fd, COL_PROTOCOL, "NBNS");
-	if (check_col(fd, COL_INFO))
-		col_clear(fd, COL_INFO);
-
-	if (pi.captured_len < NBNS_HDRLEN) {
-		if (check_col(fd, COL_INFO)) {
-			col_set_str(fd, COL_INFO, "Short NBNS packet");
-		}
-		old_dissect_data(pd, offset, fd, tree);
-		return;
-	}
+	if (check_col(pinfo->fd, COL_PROTOCOL))
+		col_set_str(pinfo->fd, COL_PROTOCOL, "NBNS");
+	if (check_col(pinfo->fd, COL_INFO))
+		col_clear(pinfo->fd, COL_INFO);
 
 	/* To do: check for runts, errs, etc. */
-	id    = pntohs(&pd[offset + NBNS_ID]);
-	flags = pntohs(&pd[offset + NBNS_FLAGS]);
-	quest = pntohs(&pd[offset + NBNS_QUEST]);
-	ans   = pntohs(&pd[offset + NBNS_ANS]);
-	auth  = pntohs(&pd[offset + NBNS_AUTH]);
-	add   = pntohs(&pd[offset + NBNS_ADD]);
-
-	if (check_col(fd, COL_INFO)) {
-		col_add_fstr(fd, COL_INFO, "%s%s",
+	id    = tvb_get_ntohs(tvb, offset + NBNS_ID);
+	flags = tvb_get_ntohs(tvb, offset + NBNS_FLAGS);
+
+	if (check_col(pinfo->fd, COL_INFO)) {
+		col_add_fstr(pinfo->fd, COL_INFO, "%s%s",
 		    val_to_str(flags & F_OPCODE, opcode_vals,
 		      "Unknown operation (%x)"),
 		    (flags & F_RESPONSE) ? " response" : "");
+		fd = pinfo->fd;
 	} else {
 		/* Set "fd" to NULL; we pass a NULL "fd" to the query and
 		   answer dissectors, as a way of saying that they shouldn't
@@ -1173,28 +1010,42 @@ dissect_nbns(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
 	}
 
 	if (tree) {
-		ti = proto_tree_add_item(tree, proto_nbns, NullTVB, offset, END_OF_FRAME, FALSE);
+		ti = proto_tree_add_item(tree, proto_nbns, tvb, offset,
+		    tvb_length(tvb), FALSE);
 		nbns_tree = proto_item_add_subtree(ti, ett_nbns);
 
 		if (flags & F_RESPONSE) {
-			proto_tree_add_boolean_hidden(nbns_tree, hf_nbns_response, NullTVB, 
+			proto_tree_add_boolean_hidden(nbns_tree, hf_nbns_response, tvb, 
 					     0, 0, TRUE);
 		} else {
-			proto_tree_add_boolean_hidden(nbns_tree, hf_nbns_query, NullTVB, 
+			proto_tree_add_boolean_hidden(nbns_tree, hf_nbns_query, tvb, 
 					     0, 0, TRUE);
 		}
 
-		proto_tree_add_uint(nbns_tree, hf_nbns_transaction_id, NullTVB,
+		proto_tree_add_uint(nbns_tree, hf_nbns_transaction_id, tvb,
 				    offset + NBNS_ID, 2, id);
 
-		nbns_add_nbns_flags(nbns_tree, offset + NBNS_FLAGS, flags, 0);
-		proto_tree_add_uint(nbns_tree, hf_nbns_count_questions, NullTVB,
+		nbns_add_nbns_flags(nbns_tree, tvb, offset + NBNS_FLAGS,
+				    flags, 0);
+	}
+	quest = tvb_get_ntohs(tvb, offset + NBNS_QUEST);
+	if (tree) {
+		proto_tree_add_uint(nbns_tree, hf_nbns_count_questions, tvb,
 				    offset + NBNS_QUEST, 2, quest);
-		proto_tree_add_uint(nbns_tree, hf_nbns_count_answers, NullTVB,
+	}
+	ans = tvb_get_ntohs(tvb, offset + NBNS_ANS);
+	if (tree) {
+		proto_tree_add_uint(nbns_tree, hf_nbns_count_answers, tvb,
 				    offset + NBNS_ANS, 2, ans);
-		proto_tree_add_uint(nbns_tree, hf_nbns_count_auth_rr, NullTVB,
+	}
+	auth = tvb_get_ntohs(tvb, offset + NBNS_AUTH);
+	if (tree) {
+		proto_tree_add_uint(nbns_tree, hf_nbns_count_auth_rr, tvb,
 				    offset + NBNS_AUTH, 2, auth);
-		proto_tree_add_uint(nbns_tree, hf_nbns_count_add_rr, NullTVB,
+	}
+	add = tvb_get_ntohs(tvb, offset + NBNS_ADD);
+	if (tree) {
+		proto_tree_add_uint(nbns_tree, hf_nbns_count_add_rr, tvb,
 				    offset + NBNS_ADD, 2, add);
 	}
 
@@ -1204,7 +1055,7 @@ dissect_nbns(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
 		/* If this is a response, don't add information about the
 		   queries to the summary, just add information about the
 		   answers. */
-		cur_off += dissect_query_records(pd, cur_off,
+		cur_off += dissect_query_records(tvb, cur_off,
 		    nbns_data_offset, quest,
 		    (!(flags & F_RESPONSE) ? fd : NULL), nbns_tree);
 	}
@@ -1213,7 +1064,7 @@ dissect_nbns(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
 		/* If this is a request, don't add information about the
 		   answers to the summary, just add information about the
 		   queries. */
-		cur_off += dissect_answer_records(pd, cur_off,
+		cur_off += dissect_answer_records(tvb, cur_off,
 			nbns_data_offset, ans,
 			((flags & F_RESPONSE) ? fd : NULL), nbns_tree,
 			flags & F_OPCODE, "Answers");
@@ -1223,14 +1074,14 @@ dissect_nbns(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
 		/* Don't add information about the authoritative name
 		   servers, or the additional records, to the summary. */
 		if (auth > 0)
-			cur_off += dissect_answer_records(pd, cur_off,
+			cur_off += dissect_answer_records(tvb, cur_off,
 					nbns_data_offset,
 					auth, NULL, nbns_tree,
 					flags & F_OPCODE,
 					"Authoritative nameservers");
 
 		if (add > 0)
-			cur_off += dissect_answer_records(pd, cur_off,
+			cur_off += dissect_answer_records(tvb, cur_off,
 					nbns_data_offset,
 					add, NULL, nbns_tree,
 					flags & F_OPCODE,
@@ -1259,14 +1110,15 @@ struct nbdgm_header {
 };
 
 static void
-dissect_nbdgm(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
+dissect_nbdgm(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 {
+	int			offset = 0;
 	proto_tree		*nbdgm_tree = NULL;
 	proto_item		*ti;
 	struct nbdgm_header	header;
 	int			flags;
 	int			message_index;
-	int			max_data = pi.captured_len - offset;
+	int			max_data = tvb_length_remaining(tvb, offset);
 
 	char *message[] = {
 		"Unknown",
@@ -1299,29 +1151,29 @@ dissect_nbdgm(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
 	int name_type;
 	int len;
 
-	if (check_col(fd, COL_PROTOCOL))
-		col_set_str(fd, COL_PROTOCOL, "NBDS");
-	if (check_col(fd, COL_INFO))
-		col_clear(fd, COL_INFO);
+	if (check_col(pinfo->fd, COL_PROTOCOL))
+		col_set_str(pinfo->fd, COL_PROTOCOL, "NBDS");
+	if (check_col(pinfo->fd, COL_INFO))
+		col_clear(pinfo->fd, COL_INFO);
 
-	header.msg_type = pd[offset];
+	header.msg_type = tvb_get_guint8(tvb, offset);
 	
-	flags = pd[offset+1];
+	flags = tvb_get_guint8(tvb, offset+1);
 	header.flags.more = flags & 1;
 	header.flags.first = (flags & 2) >> 1;
 	header.flags.node_type = (flags & 12) >> 2;
 
-	header.dgm_id = pntohs(&pd[offset+2]);
-	memcpy(&header.src_ip, &pd[offset+4], 4);
-	header.src_port = pntohs(&pd[offset+8]);
+	header.dgm_id = tvb_get_ntohs(tvb, offset+2);
+	tvb_memcpy(tvb, (guint8 *)&header.src_ip, offset+4, 4);
+	header.src_port = tvb_get_ntohs(tvb, offset+8);
 
 	if (header.msg_type == 0x10 ||
 			header.msg_type == 0x11 || header.msg_type == 0x12) {
-		header.dgm_length = pntohs(&pd[offset+10]);
-		header.pkt_offset = pntohs(&pd[offset+12]);
+		header.dgm_length = tvb_get_ntohs(tvb, offset+10);
+		header.pkt_offset = tvb_get_ntohs(tvb, offset+12);
 	}
 	else if (header.msg_type == 0x13) {
-		header.error_code = pntohs(&pd[offset+10]);
+		header.error_code = tvb_get_ntohs(tvb, offset+10);
 	}
 
 	message_index = header.msg_type - 0x0f;
@@ -1329,40 +1181,40 @@ dissect_nbdgm(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
 		message_index = 0;
 	}
 
-	if (check_col(fd, COL_INFO)) {
-		col_set_str(fd, COL_INFO, message[message_index]);
+	if (check_col(pinfo->fd, COL_INFO)) {
+		col_set_str(pinfo->fd, COL_INFO, message[message_index]);
 	}
 
 	if (tree) {
-		ti = proto_tree_add_item(tree, proto_nbdgm, NullTVB, offset, header.dgm_length, FALSE);
+		ti = proto_tree_add_item(tree, proto_nbdgm, tvb, offset, header.dgm_length, FALSE);
 		nbdgm_tree = proto_item_add_subtree(ti, ett_nbdgm);
 
-		proto_tree_add_uint_format(nbdgm_tree, hf_nbdgm_type, NullTVB,
+		proto_tree_add_uint_format(nbdgm_tree, hf_nbdgm_type, tvb,
 					   offset, 1, 
 					   header.msg_type,   
 					   "Message Type: %s",
 					   message[message_index]);
-		proto_tree_add_boolean_format(nbdgm_tree, hf_nbdgm_fragment, NullTVB,
+		proto_tree_add_boolean_format(nbdgm_tree, hf_nbdgm_fragment, tvb,
 					   offset+1, 1, 
 					   header.flags.more,
 					   "More fragments follow: %s",
 					   yesno[header.flags.more]);
-		proto_tree_add_boolean_format(nbdgm_tree, hf_nbdgm_first, NullTVB,
+		proto_tree_add_boolean_format(nbdgm_tree, hf_nbdgm_first, tvb,
 					   offset+1, 1, 
 					   header.flags.first,
 					   "This is first fragment: %s",
 					   yesno[header.flags.first]);
-		proto_tree_add_uint_format(nbdgm_tree, hf_nbdgm_node_type, NullTVB,
+		proto_tree_add_uint_format(nbdgm_tree, hf_nbdgm_node_type, tvb,
 					   offset+1, 1, 
 					   header.flags.node_type,
 					   "Node Type: %s",
 					   node[header.flags.node_type]);
 
-		proto_tree_add_uint(nbdgm_tree, hf_nbdgm_datagram_id, NullTVB,
+		proto_tree_add_uint(nbdgm_tree, hf_nbdgm_datagram_id, tvb,
 				    offset+2, 2, header.dgm_id);
-		proto_tree_add_ipv4(nbdgm_tree, hf_nbdgm_src_ip, NullTVB,
+		proto_tree_add_ipv4(nbdgm_tree, hf_nbdgm_src_ip, tvb,
 				    offset+4, 4, header.src_ip);
-		proto_tree_add_uint(nbdgm_tree, hf_nbdgm_src_port, NullTVB,
+		proto_tree_add_uint(nbdgm_tree, hf_nbdgm_src_port, tvb,
 				    offset+8, 2, header.src_port);
 
 	}
@@ -1374,9 +1226,9 @@ dissect_nbdgm(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
 			header.msg_type == 0x11 || header.msg_type == 0x12) {
 
 		if (tree) {
-			proto_tree_add_text(nbdgm_tree, NullTVB, offset, 2,
+			proto_tree_add_text(nbdgm_tree, tvb, offset, 2,
 					"Datagram length: %d bytes", header.dgm_length);
-			proto_tree_add_text(nbdgm_tree, NullTVB, offset+2, 2,
+			proto_tree_add_text(nbdgm_tree, tvb, offset+2, 2,
 					"Packet offset: %d bytes", header.pkt_offset);
 		}
 
@@ -1384,41 +1236,53 @@ dissect_nbdgm(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
 		max_data -= 4;
 
 		/* Source name */
-		len = get_nbns_name(pd, offset, offset, name, &name_type);
+		len = get_nbns_name(tvb, offset, offset, name, &name_type);
 
 		if (tree) {
-			add_name_and_type(nbdgm_tree, offset, len,
+			add_name_and_type(nbdgm_tree, tvb, offset, len,
 			    "Source name", name, name_type);
 		}
 		offset += len;
 		max_data -= len;
 
 		/* Destination name */
-		len = get_nbns_name(pd, offset, offset, name, &name_type);
+		len = get_nbns_name(tvb, offset, offset, name, &name_type);
 
 		if (tree) {
-			add_name_and_type(nbdgm_tree, offset, len,
+			add_name_and_type(nbdgm_tree, tvb, offset, len,
 			    "Destination name", name, name_type);
 		}
 		offset += len;
 		max_data -= len;
 
-		/* here we can pass the packet off to the next protocol */
-		dissect_smb(pd, offset, fd, tree, max_data);
+		  /*
+		   * Here we can pass the packet off to the next protocol.
+		   */
+		  {
+			tvbuff_t	*next_tvb;
+			const guint8	*next_pd;
+			int		next_offset;
+
+			next_tvb = tvb_new_subset(tvb, offset, -1, -1);
+			tvb_compat(next_tvb, &next_pd, &next_offset);
+
+			dissect_smb(next_pd, next_offset, pinfo->fd, tree,
+			    max_data);
+		  }
 	}
 	else if (header.msg_type == 0x13) {
 		if (tree) {
-			proto_tree_add_text(nbdgm_tree, NullTVB, offset, 1, "Error code: %s",
+			proto_tree_add_text(nbdgm_tree, tvb, offset, 1, "Error code: %s",
 				val_to_str(header.error_code, error_codes, "Unknown (0x%x)"));
 		}
 	}
 	else if (header.msg_type == 0x14 ||
 			header.msg_type == 0x15 || header.msg_type == 0x16) {
 		/* Destination name */
-		len = get_nbns_name(pd, offset, offset, name, &name_type);
+		len = get_nbns_name(tvb, offset, offset, name, &name_type);
 
 		if (tree) {
-			add_name_and_type(nbdgm_tree, offset, len,
+			add_name_and_type(nbdgm_tree, tvb, offset, len,
 			    "Destination name", name, name_type);
 		}
 	}
@@ -1473,7 +1337,8 @@ static const value_string error_codes[] = {
  * (MMM). ]
  */
 static int
-dissect_nbss_packet(const u_char *pd, int offset, frame_data *fd, proto_tree *tree, int max_data, int is_cifs)
+dissect_nbss_packet(tvbuff_t *tvb, int offset, packet_info *pinfo,
+    proto_tree *tree, int max_data, int is_cifs)
 {
 	proto_tree	*nbss_tree = NULL;
 	proto_item	*ti;
@@ -1486,23 +1351,23 @@ dissect_nbss_packet(const u_char *pd, int offset, frame_data *fd, proto_tree *tr
 	char		name[(NETBIOS_NAME_LEN - 1)*4 + MAXDNAME];
 	int		name_type;
 
-	msg_type = pd[offset];
+	msg_type = tvb_get_guint8(tvb, offset);
 
 	if (is_cifs) {
 		flags = 0;
-		length = pntohl(&pd[offset]) & 0x00FFFFFF;
+		length = tvb_get_ntoh24(tvb, offset + 1);
 	} else {
-		flags = pd[offset + 1];
-		length = pntohs(&pd[offset + 2]);
+		flags = tvb_get_guint8(tvb, offset + 1);
+		length = tvb_get_ntohs(tvb, offset + 2);
 		if (flags & NBSS_FLAGS_E)
 			length += 65536;
 	}
 
 	if (tree) {
-	  ti = proto_tree_add_item(tree, proto_nbss, NullTVB, offset, length + 4, FALSE);
+	  ti = proto_tree_add_item(tree, proto_nbss, tvb, offset, length + 4, FALSE);
 	  nbss_tree = proto_item_add_subtree(ti, ett_nbss);
 	  
-	  proto_tree_add_uint_format(nbss_tree, hf_nbss_type, NullTVB,
+	  proto_tree_add_uint_format(nbss_tree, hf_nbss_type, tvb,
 				     offset, 1, 
 				     msg_type,
 				     "Message Type: %s",
@@ -1514,21 +1379,21 @@ dissect_nbss_packet(const u_char *pd, int offset, frame_data *fd, proto_tree *tr
 
 	if (is_cifs) {
 		if (tree) {
-		  proto_tree_add_text(nbss_tree, NullTVB, offset, 3, "Length: %u", length);
+		  proto_tree_add_text(nbss_tree, tvb, offset, 3, "Length: %u", length);
 		}
 		offset += 3;
 	} else {
 		if (tree) {
-		  tf = proto_tree_add_uint(nbss_tree, hf_nbss_flags, NullTVB, offset, 1, flags);
+		  tf = proto_tree_add_uint(nbss_tree, hf_nbss_flags, tvb, offset, 1, flags);
 		  field_tree = proto_item_add_subtree(tf, ett_nbss_flags);
-		  proto_tree_add_text(field_tree, NullTVB, offset, 1, "%s",
+		  proto_tree_add_text(field_tree, tvb, offset, 1, "%s",
 			      decode_boolean_bitfield(flags, NBSS_FLAGS_E,
 							      8, "Add 65536 to length", "Add 0 to length"));
 		}
 		offset += 1;
 
 		if (tree) {
-		  proto_tree_add_text(nbss_tree, NullTVB, offset, 2, "Length: %u", length);
+		  proto_tree_add_text(nbss_tree, tvb, offset, 2, "Length: %u", length);
 		}
 
 		offset += 2;
@@ -1537,38 +1402,40 @@ dissect_nbss_packet(const u_char *pd, int offset, frame_data *fd, proto_tree *tr
 	switch (msg_type) {
 
 	case SESSION_REQUEST:
-	  len = get_nbns_name(pd, offset, offset, name, &name_type);
+	  len = get_nbns_name(tvb, offset, offset, name, &name_type);
 	  if (tree)
-	    add_name_and_type(nbss_tree, offset, len,
+	    add_name_and_type(nbss_tree, tvb, offset, len,
 				"Called name", name, name_type);
 	  offset += len;
 
-	  len = get_nbns_name(pd, offset, offset, name, &name_type);
+	  len = get_nbns_name(tvb, offset, offset, name, &name_type);
 	  
 	  if (tree)
-	    add_name_and_type(nbss_tree, offset, len,
+	    add_name_and_type(nbss_tree, tvb, offset, len,
 				"Calling name", name, name_type);
 
 	  break;
 
 	case NEGATIVE_SESSION_RESPONSE:
 	  if (tree) 
-	    proto_tree_add_text(nbss_tree, NullTVB, offset, 1,
+	    proto_tree_add_text(nbss_tree, tvb, offset, 1,
 				"Error code: %s",
-				val_to_str(pd[offset], error_codes, "Unknown (%x)"));
+				val_to_str(tvb_get_guint8(tvb, offset),
+					   error_codes, "Unknown (%x)"));
 	  break;
 
 	case RETARGET_SESSION_RESPONSE:
 	  if (tree)
-	    proto_tree_add_text(nbss_tree, NullTVB, offset, 4,
+	    proto_tree_add_text(nbss_tree, tvb, offset, 4,
 				"Retarget IP address: %s",
-				ip_to_str((guint8 *)&pd[offset]));
+				ip_to_str(tvb_get_ptr(tvb, offset, 4)));
 	  
 	  offset += 4;
 
 	  if (tree)
-	    proto_tree_add_text(nbss_tree, NullTVB, offset, 2,
-				"Retarget port: %u", pntohs(&pd[offset]));
+	    proto_tree_add_text(nbss_tree, tvb, offset, 2,
+				"Retarget port: %u",
+				tvb_get_ntohs(tvb, offset));
 
 	  break;
 
@@ -1576,9 +1443,17 @@ dissect_nbss_packet(const u_char *pd, int offset, frame_data *fd, proto_tree *tr
 	  /*
 	   * Here we can pass the packet off to the next protocol.
 	   */
+	  {
+		tvbuff_t	*next_tvb;
+		const guint8	*next_pd;
+		int		next_offset;
 
-	  dissect_smb(pd, offset, fd, tree, max_data - 4);
+		next_tvb = tvb_new_subset(tvb, offset, -1, -1);
+		tvb_compat(next_tvb, &next_pd, &next_offset);
 
+		dissect_smb(next_pd, next_offset, pinfo->fd, tree,
+		    max_data - 4);
+	  }
 	  break;
 
 	}
@@ -1586,23 +1461,28 @@ dissect_nbss_packet(const u_char *pd, int offset, frame_data *fd, proto_tree *tr
 }
 
 static void
-dissect_nbss(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
+dissect_nbss(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 {
+	int		offset = 0;
 	guint8		msg_type;
-	guint8		flags;
-	guint16		length;
-	int		len;
 	int		max_data;
-	int		is_cifs;
+	int		len;
+	gboolean	is_cifs;
 
-	if (check_col(fd, COL_PROTOCOL))
-		col_set_str(fd, COL_PROTOCOL, "NBSS");
-	if (check_col(fd, COL_INFO))
-		col_clear(fd, COL_INFO);
+	if (check_col(pinfo->fd, COL_PROTOCOL))
+		col_set_str(pinfo->fd, COL_PROTOCOL, "NBSS");
+	if (check_col(pinfo->fd, COL_INFO))
+		col_clear(pinfo->fd, COL_INFO);
 
-	msg_type = pd[offset];
+	msg_type = tvb_get_guint8(tvb, offset);
+
+	/*
+	 * XXX - we should set this based on both the length remaining
+	 * and "length"....
+	 */
+	max_data = tvb_length_remaining(tvb, offset);
 
-	if (pi.match_port == TCP_PORT_CIFS) {
+	if (pinfo->match_port == TCP_PORT_CIFS) {
 		/*
 		 * Windows 2000 CIFS clients can dispense completely
 		 * with the NETBIOS encapsulation and directly use CIFS
@@ -1611,23 +1491,11 @@ dissect_nbss(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
 		 * of 17. The only message types used are
 		 * SESSION_MESSAGE and SESSION_KEEP_ALIVE.
 		 */
-		flags = 0;
-		length = pntohl(&pd[offset]) & 0x00FFFFFF;
 		is_cifs = TRUE;
 	} else {
-		flags = pd[offset + 1];
-		length = pntohs(&pd[offset + 2]);
-		if (flags & NBSS_FLAGS_E)
-			length += 65536;
 		is_cifs = FALSE;
 	}
 
-	/*
-	 * XXX - we should set this based on both "pi.captured_len"
-	 * and "length"....
-	 */
-	max_data = pi.captured_len - offset;
-
 	/* Hmmm, it may be a continuation message ... */
 
 #define RJSHACK 1
@@ -1636,32 +1504,40 @@ dissect_nbss(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
 	     (msg_type != POSITIVE_SESSION_RESPONSE) &&
 	     (msg_type != NEGATIVE_SESSION_RESPONSE) &&
 	     (msg_type != RETARGET_SESSION_RESPONSE) &&
+	     (msg_type != SESSION_KEEP_ALIVE) &&
 	     (msg_type != SESSION_MESSAGE)) ||
 	    ((msg_type == SESSION_MESSAGE) &&
-	    (memcmp(pd + offset + 4, "\377SMB", 4) != 0))) {
+	     (max_data < 8 || tvb_memeql(tvb, offset + 4, "\377SMB", 4) != 0))) {
  
-	  if (check_col(fd, COL_INFO)) {
-	    col_add_fstr(fd, COL_INFO, "NBSS Continuation Message");
+	  /*
+	   * Either the first byte isn't one of the known message types,
+	   * or it's a session message but we either don't have enough
+	   * data in the frame for the NBSS/CIFS header plus an SMB header,
+	   * or we do but the message data doesn't begin with 0xFF S M B.
+	   * Assume it's a continuation message.
+	   */
+	  if (check_col(pinfo->fd, COL_INFO)) {
+	    col_add_fstr(pinfo->fd, COL_INFO, "NBSS Continuation Message");
 	  }
 
 	  if (tree)
-	    proto_tree_add_text(tree, NullTVB, offset, max_data, "Continuation data");
+	    proto_tree_add_text(tree, tvb, offset, max_data, "Continuation data");
 
 	  return;
 	}
 #endif
 
-	if (check_col(fd, COL_INFO)) {
-		col_add_fstr(fd, COL_INFO,
+	if (check_col(pinfo->fd, COL_INFO)) {
+		col_add_fstr(pinfo->fd, COL_INFO,
 		    val_to_str(msg_type, message_types, "Unknown (%x)"));
 	}
 
 	while (max_data > 0) {
-		len = dissect_nbss_packet(pd, offset, fd, tree, max_data, is_cifs);
+		len = dissect_nbss_packet(tvb, offset, pinfo, tree, max_data,
+		    is_cifs);
 		offset += len;
 		max_data -= len;
 	}
-
 }
 
 void
@@ -1771,8 +1647,8 @@ proto_register_nbt(void)
 void
 proto_reg_handoff_nbt(void)
 {
-  old_dissector_add("udp.port", UDP_PORT_NBNS, dissect_nbns, proto_nbns);
-  old_dissector_add("udp.port", UDP_PORT_NBDGM, dissect_nbdgm, proto_nbdgm);
-  old_dissector_add("tcp.port", TCP_PORT_NBSS, dissect_nbss, proto_nbss);
-  old_dissector_add("tcp.port", TCP_PORT_CIFS, dissect_nbss, proto_nbss);
+  dissector_add("udp.port", UDP_PORT_NBNS, dissect_nbns, proto_nbns);
+  dissector_add("udp.port", UDP_PORT_NBDGM, dissect_nbdgm, proto_nbdgm);
+  dissector_add("tcp.port", TCP_PORT_NBSS, dissect_nbss, proto_nbss);
+  dissector_add("tcp.port", TCP_PORT_CIFS, dissect_nbss, proto_nbss);
 }