Tvbuffify the CDP, CGMP, ISL, and VTP dissectors.

Add a new subdissector table in the LLC dissector for protocol IDs with
a Cisco OUI, and register the CDP, CGMP, and VTMP dissectors in that
table, rather than calling them via a switch statement.

Register the ISL dissector by name, and have the Ethernet dissector call
it via a handle.

Fix the handling of the checksum field in the CDP dissector.

The strings in CDP are counted, not null-terminated; treat them as such.

Fix the handling of the encapsulated frame CRC, and the encapsulated
frame, in the ISL dissector, at least for Ethernet frames; it may not be
correct for encapsulated Token Ring frames.

svn path=/trunk/; revision=2792

1 files changed, 244 insertions, 248 deletions

diff --git a/packet-cdp.c b/packet-cdp.c
index f33b7424af..2b55293d57 100644
--- a/packet-cdp.c
+++ b/packet-cdp.c
@@ -2,7 +2,7 @@
  * Routines for the disassembly of the "Cisco Discovery Protocol"
  * (c) Copyright Hannes R. Boehm <hannes@boehm.org>
  *
- * $Id: packet-cdp.c,v 1.27 2000/11/19 08:53:56 guy Exp $
+ * $Id: packet-cdp.c,v 1.28 2000/12/28 09:49:09 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@zing.org>
@@ -52,7 +52,7 @@
 
 static int proto_cdp = -1;
 static int hf_cdp_version = -1;
-static int hf_cdp_flags = -1;
+static int hf_cdp_checksum = -1;
 static int hf_cdp_ttl = -1;
 static int hf_cdp_tlvtype = -1;
 static int hf_cdp_tlvlength = -1;
@@ -63,12 +63,12 @@ static gint ett_cdp_address = -1;
 static gint ett_cdp_capabilities = -1;
 
 static int
-dissect_address_tlv(const u_char *pd, int offset, int length, proto_tree *tree);
+dissect_address_tlv(tvbuff_t *tvb, int offset, int length, proto_tree *tree);
 static void
-dissect_capabilities(const u_char *pd, int offset, int length, proto_tree *tree);
+dissect_capabilities(tvbuff_t *tvb, int offset, int length, proto_tree *tree);
 static void
-add_multi_line_string_to_tree(proto_tree *tree, gint start, gint len,
-  const gchar *prefix, const gchar *string);
+add_multi_line_string_to_tree(proto_tree *tree, tvbuff_t *tvb, gint start,
+  gint len, const gchar *prefix);
 
 #define TYPE_DEVICE_ID		0x0001
 #define TYPE_ADDRESS		0x0002
@@ -87,193 +87,190 @@ static const value_string type_vals[] = {
 	{ 0,                 NULL },
 };
 	
-void 
-dissect_cdp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
+static void 
+dissect_cdp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 {
     proto_item *ti; 
     proto_tree *cdp_tree = NULL;
+    int offset = 0;
     guint16 type;
     guint16 length;
-    char *type_str;
-    char *stringmem;
     proto_item *tlvi;
     proto_tree *tlv_tree;
     int real_length;
     guint32 naddresses;
     int addr_length;
 
-    OLD_CHECK_DISPLAY_AS_DATA(proto_cdp, pd, offset, fd, tree);
+    CHECK_DISPLAY_AS_DATA(proto_cdp, tvb, pinfo, tree);
 
-    if (check_col(fd, COL_PROTOCOL))
-        col_set_str(fd, COL_PROTOCOL, "CDP");
-    if (check_col(fd, COL_INFO))
-        col_set_str(fd, COL_INFO, "Cisco Discovery Protocol"); 
+    pinfo->current_proto = "CDP";
 
-    if(tree){
-        ti = proto_tree_add_item(tree, proto_cdp, NullTVB, offset, END_OF_FRAME, FALSE);
+    if (check_col(pinfo->fd, COL_PROTOCOL))
+        col_set_str(pinfo->fd, COL_PROTOCOL, "CDP");
+    if (check_col(pinfo->fd, COL_INFO))
+        col_set_str(pinfo->fd, COL_INFO, "Cisco Discovery Protocol"); 
+
+    if (tree){
+        ti = proto_tree_add_item(tree, proto_cdp, tvb, offset,
+        			 tvb_length_remaining(tvb, offset), FALSE);
 	cdp_tree = proto_item_add_subtree(ti, ett_cdp);
 	
 	/* CDP header */
-	proto_tree_add_uint(cdp_tree, hf_cdp_version, NullTVB, offset, 1, pd[offset]);
+	proto_tree_add_item(cdp_tree, hf_cdp_version, tvb, offset, 1, FALSE);
 	offset += 1;
-	proto_tree_add_uint_format(cdp_tree, hf_cdp_ttl, NullTVB, offset, 1,
-				   pntohs(&pd[offset]),
-				   "TTL: %u seconds", pd[offset]);
+	proto_tree_add_uint_format(cdp_tree, hf_cdp_ttl, tvb, offset, 1,
+				   tvb_get_guint8(tvb, offset),
+				   "TTL: %u seconds",
+				   tvb_get_guint8(tvb, offset));
 	offset += 1;
-	proto_tree_add_uint_format(cdp_tree, hf_cdp_flags, NullTVB, offset, 2,
-				   pd[offset], 
-				   "Checksum: 0x%04x", pntohs(&pd[offset]));
+	proto_tree_add_item(cdp_tree, hf_cdp_checksum, tvb, offset, 2, FALSE);
 	offset += 2;
 
-	while( IS_DATA_IN_FRAME(offset) ){
-		type = pntohs(&pd[offset + TLV_TYPE]);
-		length = pntohs(&pd[offset + TLV_LENGTH]);
-		type_str = val_to_str(type, type_vals,
-		    "Unknown (0x%04x)");
-
-		switch( type ){
-			case TYPE_DEVICE_ID:
-				/* Device ID */
-				tlvi = proto_tree_add_text(cdp_tree, NullTVB, offset,
-				    length, "Device ID: %s",
-				    &pd[offset+4]);
-				tlv_tree = proto_item_add_subtree(tlvi,
-				    ett_cdp_tlv);
-				proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, NullTVB,
-				    offset + TLV_TYPE, 2, type);
-				proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, NullTVB,
-				    offset + TLV_LENGTH, 2, length);
-				proto_tree_add_text(tlv_tree, NullTVB, offset + 4,
-				    length - 4, "Device ID: %s",
-				    &pd[offset+4]);
-				offset+=length;
-				break;
-			case TYPE_ADDRESS:
-				/* Addresses */
-				tlvi = proto_tree_add_text(cdp_tree, NullTVB, offset,
-				    length, "Addresses");
-				tlv_tree = proto_item_add_subtree(tlvi,
-				    ett_cdp_tlv);
-				proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, NullTVB,
-				    offset + TLV_TYPE, 2, type);
-				proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, NullTVB,
-				    offset + TLV_LENGTH, 2, length);
-				offset += 4;
-				length -= 4;
-				naddresses = pntohl(&pd[offset]);
-				proto_tree_add_text(tlv_tree, NullTVB, offset, 4,
-				    "Number of addresses: %u", naddresses);
-				offset += 4;
-				length -= 4;
-				while (naddresses != 0) {
-				    addr_length = dissect_address_tlv(pd,
-				        offset, length, tlv_tree);
-				    if (addr_length < 0)
-					break;
-				    offset += addr_length;
-				    length -= addr_length;
-
-				    naddresses--;
-				}
-				offset += length;
-				break;
-			case TYPE_PORT_ID:
-				real_length = length;
-				if (pd[offset + real_length] != 0x00) {
-				    /* The length in the TLV doesn't
-				       appear to be the length of the
-				       TLV, as the byte just past it
-				       isn't the first byte of a 2-byte
-				       big-endian small integer; make
-				       the length of the TLV the length
-				       in the TLV, plus 4 bytes for the
-				       TLV type and length, minus 1
-				       because that's what makes one
-				       capture work. */
-				    real_length = length + 3;
-				}
-				tlvi = proto_tree_add_text(cdp_tree, NullTVB, offset,
-				    real_length, "Port ID: %s",
-				    &pd[offset+4]);
-				tlv_tree = proto_item_add_subtree(tlvi,
-				    ett_cdp_tlv);
-				proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, NullTVB,
-				    offset + TLV_TYPE, 2, type);
-				proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, NullTVB,
-				    offset + TLV_LENGTH, 2, length);
-				proto_tree_add_text(tlv_tree, NullTVB, offset + 4,
-				    real_length - 4,
-				    "Sent through Interface: %s",
-				    &pd[offset+4]);
-				offset += real_length;
-				break;
-			case TYPE_CAPABILITIES:
-				tlvi = proto_tree_add_text(cdp_tree, NullTVB, offset,
-				    length, "Capabilities");
-				tlv_tree = proto_item_add_subtree(tlvi,
-				    ett_cdp_tlv);
-				proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, NullTVB,
-				    offset + TLV_TYPE, 2, type);
-				proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, NullTVB,
-				    offset + TLV_LENGTH, 2, length);
-				offset += 4;
-				length -= 4;
-				dissect_capabilities(pd, offset, length,
-				    tlv_tree);
-				offset += length;
-				break;
-			case TYPE_IOS_VERSION:
-				tlvi = proto_tree_add_text(cdp_tree, NullTVB, offset,
-				    length, "Software Version");
-				tlv_tree = proto_item_add_subtree(tlvi,
-				    ett_cdp_tlv);
-				proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, NullTVB,
-				    offset + TLV_TYPE, 2, type);
-				proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, NullTVB,
-				    offset + TLV_LENGTH, 2, length);
-				add_multi_line_string_to_tree(tlv_tree,
-				    offset + 4, length - 4, "Software Version: ",
-				    &pd[offset+4] );
-				offset += length;
-				break;
-			case TYPE_PLATFORM:
-				/* ??? platform */
-				stringmem = malloc(length);
-				memset(stringmem, '\0', length);
-				memcpy(stringmem, &pd[offset+4], length - 4 );
-				tlvi = proto_tree_add_text(cdp_tree, NullTVB,
-				    offset, length, "Platform: %s",
-				    stringmem);
-				tlv_tree = proto_item_add_subtree(tlvi,
-				    ett_cdp_tlv);
-				proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, NullTVB,
-				    offset + TLV_TYPE, 2, type);
-				proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, NullTVB,
-				    offset + TLV_LENGTH, 2, length);
-				proto_tree_add_text(tlv_tree, NullTVB, offset + 4,
-				    length - 4, "Platform: %s", stringmem);
-				free(stringmem);
-				offset+=length;
-				break;
-			default:
-				tlvi = proto_tree_add_text(cdp_tree, NullTVB, offset,
-				    length, "Type: %s, length: %u",
-				    type_str, length);
-				tlv_tree = proto_item_add_subtree(tlvi,
-				    ett_cdp_tlv);
-				proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, NullTVB,
-				    offset + TLV_TYPE, 2, type);
-				proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, NullTVB,
-				    offset + TLV_LENGTH, 2, length);
-				if (length > 4) {
-					proto_tree_add_text(tlv_tree, NullTVB,
-					    offset + 4, length - 4, "Data");
-				} else
-					return;
-				offset+=length;
+	while (tvb_reported_length_remaining(tvb, offset) != 0) {
+	    type = tvb_get_ntohs(tvb, offset + TLV_TYPE);
+	    length = tvb_get_ntohs(tvb, offset + TLV_LENGTH);
+
+	    switch (type) {
+
+	    case TYPE_DEVICE_ID:
+		/* Device ID */
+		tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
+			    length, "Device ID: %.*s",
+			    length - 4,
+			    tvb_get_ptr(tvb, offset + 4, length - 4));
+		tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
+		proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
+			    offset + TLV_TYPE, 2, type);
+		proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
+			    offset + TLV_LENGTH, 2, length);
+		proto_tree_add_text(tlv_tree, tvb, offset + 4,
+			    length - 4, "Device ID: %.*s",
+			    length - 4,
+			    tvb_get_ptr(tvb, offset + 4, length - 4));
+		offset += length;
+		break;
+
+	    case TYPE_ADDRESS:
+		/* Addresses */
+		tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
+			    length, "Addresses");
+		tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
+		proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
+			    offset + TLV_TYPE, 2, type);
+		proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
+			    offset + TLV_LENGTH, 2, length);
+		offset += 4;
+		length -= 4;
+		naddresses = tvb_get_ntohl(tvb, offset);
+		proto_tree_add_text(tlv_tree, tvb, offset, 4,
+			    "Number of addresses: %u", naddresses);
+		offset += 4;
+		length -= 4;
+		while (naddresses != 0) {
+		    addr_length = dissect_address_tlv(tvb, offset, length,
+		    		tlv_tree);
+		    if (addr_length < 0)
+			break;
+		    offset += addr_length;
+		    length -= addr_length;
+
+		    naddresses--;
+		}
+		offset += length;
+		break;
+
+	    case TYPE_PORT_ID:
+		real_length = length;
+		if (tvb_get_guint8(tvb, offset + real_length) != 0x00) {
+		    /* The length in the TLV doesn't appear to be the
+		       length of the TLV, as the byte just past it
+		       isn't the first byte of a 2-byte big-endian
+		       small integer; make the length of the TLV the length
+		       in the TLV, plus 4 bytes for the TLV type and length,
+		       minus 1 because that's what makes one capture work. */
+		    real_length = length + 3;
 		}
+		tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
+			    real_length, "Port ID: %.*s",
+			    real_length - 4,
+			    tvb_get_ptr(tvb, offset + 4, real_length - 4));
+		tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
+		proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
+			    offset + TLV_TYPE, 2, type);
+		proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
+			    offset + TLV_LENGTH, 2, length);
+		proto_tree_add_text(tlv_tree, tvb, offset + 4,
+			    real_length - 4,
+			    "Sent through Interface: %.*s",
+			    real_length - 4,
+			    tvb_get_ptr(tvb, offset + 4, real_length - 4));
+		offset += real_length;
+		break;
+
+	    case TYPE_CAPABILITIES:
+		tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
+			    length, "Capabilities");
+		tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
+		proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
+			    offset + TLV_TYPE, 2, type);
+		proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
+			    offset + TLV_LENGTH, 2, length);
+		offset += 4;
+		length -= 4;
+		dissect_capabilities(tvb, offset, length, tlv_tree);
+		offset += length;
+		break;
+
+	    case TYPE_IOS_VERSION:
+		tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
+			    length, "Software Version");
+		tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
+		proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
+			    offset + TLV_TYPE, 2, type);
+		proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
+			    offset + TLV_LENGTH, 2, length);
+		add_multi_line_string_to_tree(tlv_tree, tvb, offset + 4,
+				length - 4, "Software Version: ");
+		offset += length;
+		break;
+
+	    case TYPE_PLATFORM:
+		/* ??? platform */
+		tlvi = proto_tree_add_text(cdp_tree, tvb,
+			    offset, length, "Platform: %.*s",
+			    length - 4,
+			    tvb_get_ptr(tvb, offset + 4, length - 4));
+		tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
+		proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
+			    offset + TLV_TYPE, 2, type);
+		proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
+			    offset + TLV_LENGTH, 2, length);
+		proto_tree_add_text(tlv_tree, tvb, offset + 4,
+			    length - 4, "Platform: %.*s",
+			    length - 4,
+			    tvb_get_ptr(tvb, offset + 4, length - 4));
+		offset += length;
+		break;
+
+	    default:
+		tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
+			    length, "Type: %s, length: %u",
+			    val_to_str(type, type_vals, "Unknown (0x%04x)"),
+			    length);
+		tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
+		proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
+			    offset + TLV_TYPE, 2, type);
+		proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
+			    offset + TLV_LENGTH, 2, length);
+		if (length > 4) {
+			proto_tree_add_text(tlv_tree, tvb, offset + 4,
+					length - 4, "Data");
+		} else
+			return;
+		offset += length;
+	    }
 	}
-    	old_dissect_data(pd, offset, fd, cdp_tree);
+    	dissect_data(tvb, offset, pinfo, cdp_tree);
     }
 }
 
@@ -287,7 +284,7 @@ static const value_string proto_type_vals[] = {
 };
 
 static int
-dissect_address_tlv(const u_char *pd, int offset, int length, proto_tree *tree)
+dissect_address_tlv(tvbuff_t *tvb, int offset, int length, proto_tree *tree)
 {
     proto_item *ti;
     proto_tree *address_tree;
@@ -301,10 +298,10 @@ dissect_address_tlv(const u_char *pd, int offset, int length, proto_tree *tree)
 
     if (length < 1)
         return -1;
-    ti = proto_tree_add_notext(tree, NullTVB, offset, length);
+    ti = proto_tree_add_notext(tree, tvb, offset, length);
     address_tree = proto_item_add_subtree(ti, ett_cdp_address);
-    protocol_type = pd[offset];
-    proto_tree_add_text(address_tree, NullTVB, offset, 1, "Protocol type: %s",
+    protocol_type = tvb_get_guint8(tvb, offset);
+    proto_tree_add_text(address_tree, tvb, offset, 1, "Protocol type: %s",
 	val_to_str(protocol_type, proto_type_vals, "Unknown (0x%02x)"));
     offset += 1;
     length -= 1;
@@ -313,8 +310,8 @@ dissect_address_tlv(const u_char *pd, int offset, int length, proto_tree *tree)
         proto_item_set_text(ti, "Truncated address");
 	return -1;
     }
-    protocol_length = pd[offset];
-    proto_tree_add_text(address_tree, NullTVB, offset, 1, "Protocol length: %u",
+    protocol_length = tvb_get_guint8(tvb, offset);
+    proto_tree_add_text(address_tree, tvb, offset, 1, "Protocol length: %u",
 			protocol_length);
     offset += 1;
     length -= 1;
@@ -322,20 +319,21 @@ dissect_address_tlv(const u_char *pd, int offset, int length, proto_tree *tree)
     if (length < protocol_length) {
         proto_item_set_text(ti, "Truncated address");
         if (length != 0) {
-            proto_tree_add_text(address_tree, NullTVB, offset, length,
-              "Protocol: %s (truncated)", bytes_to_str(&pd[offset], length));
+            proto_tree_add_text(address_tree, tvb, offset, length,
+              "Protocol: %s (truncated)",
+              tvb_bytes_to_str(tvb, offset, length));
         }
 	return -1;
     }
     protocol_str = NULL;
     if (protocol_type == PROTO_TYPE_NLPID && protocol_length == 1) {
-    	nlpid = pd[offset];
+    	nlpid = tvb_get_guint8(tvb, offset);
     	protocol_str = val_to_str(nlpid, nlpid_vals, "Unknown (0x%02x)");
     } else
         nlpid = -1;
     if (protocol_str == NULL)
-        protocol_str = bytes_to_str(&pd[offset], protocol_length);
-    proto_tree_add_text(address_tree, NullTVB, offset, protocol_length,
+        protocol_str = tvb_bytes_to_str(tvb, offset, protocol_length);
+    proto_tree_add_text(address_tree, tvb, offset, protocol_length,
 			"Protocol: %s", protocol_str);
     offset += protocol_length;
     length -= protocol_length;
@@ -344,8 +342,8 @@ dissect_address_tlv(const u_char *pd, int offset, int length, proto_tree *tree)
         proto_item_set_text(ti, "Truncated address");
 	return -1;
     }
-    address_length = pntohs(&pd[offset]);
-    proto_tree_add_text(address_tree, NullTVB, offset, 2, "Address length: %u",
+    address_length = tvb_get_ntohs(tvb, offset);
+    proto_tree_add_text(address_tree, tvb, offset, 2, "Address length: %u",
 			address_length);
     offset += 2;
     length -= 2;
@@ -353,8 +351,9 @@ dissect_address_tlv(const u_char *pd, int offset, int length, proto_tree *tree)
     if (length < address_length) {
         proto_item_set_text(ti, "Truncated address");
         if (length != 0) {
-            proto_tree_add_text(address_tree, NullTVB, offset, length,
-              "Address: %s (truncated)", bytes_to_str(&pd[offset], length));
+            proto_tree_add_text(address_tree, tvb, offset, length,
+              "Address: %s (truncated)",
+              tvb_bytes_to_str(tvb, offset, length));
         }
 	return -1;
     }
@@ -373,7 +372,7 @@ dissect_address_tlv(const u_char *pd, int offset, int length, proto_tree *tree)
             if (address_length == 4) {
                 /* The address is an IP address. */
                 address_type_str = "IP address";
-                address_str = ip_to_str(&pd[offset]);
+                address_str = ip_to_str(tvb_get_ptr(tvb, offset, 4));
             }
             break;
         }
@@ -381,16 +380,16 @@ dissect_address_tlv(const u_char *pd, int offset, int length, proto_tree *tree)
     if (address_type_str == NULL)
         address_type_str = "Address";
     if (address_str == NULL) {
-        address_str = bytes_to_str(&pd[offset], address_length);
+        address_str = tvb_bytes_to_str(tvb, offset, address_length);
     }
     proto_item_set_text(ti, "%s: %s", address_type_str, address_str);
-    proto_tree_add_text(address_tree, NullTVB, offset, address_length, "%s: %s",
+    proto_tree_add_text(address_tree, tvb, offset, address_length, "%s: %s",
       address_type_str, address_str);
     return 2 + protocol_length + 2 + address_length;
 }
 
 static void
-dissect_capabilities(const u_char *pd, int offset, int length, proto_tree *tree)
+dissect_capabilities(tvbuff_t *tvb, int offset, int length, proto_tree *tree)
 {
     proto_item *ti;
     proto_tree *capabilities_tree;
@@ -398,48 +397,48 @@ dissect_capabilities(const u_char *pd, int offset, int length, proto_tree *tree)
 
     if (length < 4)
         return;
-    capabilities = pntohl(&pd[offset]);
-    ti = proto_tree_add_text(tree, NullTVB, offset, length, "Capabilities: 0x%08x",
+    capabilities = tvb_get_ntohl(tvb, offset);
+    ti = proto_tree_add_text(tree, tvb, offset, length, "Capabilities: 0x%08x",
         capabilities);
     capabilities_tree = proto_item_add_subtree(ti, ett_cdp_capabilities);
-    proto_tree_add_text(capabilities_tree, NullTVB, offset, 4,
+    proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 	decode_boolean_bitfield(capabilities, 0x01, 4*8,
 	    "Performs level 3 routing",
 	    "Doesn't perform level 3 routing"));
-    proto_tree_add_text(capabilities_tree, NullTVB, offset, 4,
+    proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 	decode_boolean_bitfield(capabilities, 0x02, 4*8,
 	    "Performs level 2 transparent bridging",
 	    "Doesn't perform level 2 transparent bridging"));
-    proto_tree_add_text(capabilities_tree, NullTVB, offset, 4,
+    proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 	decode_boolean_bitfield(capabilities, 0x04, 4*8,
 	    "Performs level 2 source-route bridging",
 	    "Doesn't perform level 2 source-route bridging"));
-    proto_tree_add_text(capabilities_tree, NullTVB, offset, 4,
+    proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 	decode_boolean_bitfield(capabilities, 0x08, 4*8,
 	    "Performs level 2 switching",
 	    "Doesn't perform level 2 switching"));
-    proto_tree_add_text(capabilities_tree, NullTVB, offset, 4,
+    proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 	decode_boolean_bitfield(capabilities, 0x10, 4*8,
 	    "Sends and receives packets for network-layer protocols",
 	    "Doesn't send or receive packets for network-layer protocols"));
-    proto_tree_add_text(capabilities_tree, NullTVB, offset, 4,
+    proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 	decode_boolean_bitfield(capabilities, 0x20, 4*8,
 	    "Doesn't forward IGMP Report packets on nonrouter ports",
 	    "Forwards IGMP Report packets on nonrouter ports"));
-    proto_tree_add_text(capabilities_tree, NullTVB, offset, 4,
+    proto_tree_add_text(capabilities_tree, tvb, offset, 4,
 	decode_boolean_bitfield(capabilities, 0x40, 4*8,
 	    "Provides level 1 functionality",
 	    "Doesn't provide level 1 functionality"));
 }
 
 static void
-add_multi_line_string_to_tree(proto_tree *tree, gint start, gint len,
-  const gchar *prefix, const gchar *string)
+add_multi_line_string_to_tree(proto_tree *tree, tvbuff_t *tvb, gint start,
+  gint len, const gchar *prefix)
 {
     int prefix_len;
     int i;
     char blanks[64+1];
-    const gchar *p, *q;
+    gint next;
     int line_len;
     int data_len;
 
@@ -449,22 +448,13 @@ add_multi_line_string_to_tree(proto_tree *tree, gint start, gint len,
     for (i = 0; i < prefix_len; i++)
 	blanks[i] = ' ';
     blanks[i] = '\0';
-    p = string;
-    for (;;) {
-	q = strchr(p, '\n');
-	if (q != NULL) {
-	    line_len = q - p;
-	    data_len = line_len + 1;
-	} else {
-	    line_len = strlen(p);
-	    data_len = line_len;
-	}
-	proto_tree_add_text(tree, NullTVB, start, data_len, "%s%.*s", prefix,
-	   line_len, p);
-	if (q == NULL)
-	    break;
-	p += data_len;
+    while (len > 0) {
+	line_len = tvb_find_line_end(tvb, start, len, &next);
+	data_len = next - start;
+	proto_tree_add_text(tree, tvb, start, data_len, "%s%.*s", prefix,
+	   line_len, tvb_get_ptr(tvb, start, line_len));
 	start += data_len;
+	len -= data_len;
 	prefix = blanks;
     }
 }
@@ -472,35 +462,41 @@ add_multi_line_string_to_tree(proto_tree *tree, gint start, gint len,
 void
 proto_register_cdp(void)
 {
-        static hf_register_info hf[] = {
-                { &hf_cdp_version,
-                { "Version",		"cdp.version",  FT_UINT8, BASE_DEC, NULL, 0x0,
-			"" }},
-
-                { &hf_cdp_flags,
-                { "Flags",		"cdp.flags", FT_UINT8, BASE_HEX, NULL, 0x0,
-			"" }},
-
-                { &hf_cdp_ttl,
-                { "TTL",		"cdp.ttl", FT_UINT16, BASE_DEC, NULL, 0x0,
-			"" }},
-
-                { &hf_cdp_tlvtype,
-                { "Type",		"cdp.tlv.type", FT_UINT16, BASE_HEX, VALS(type_vals), 0x0,
-			"" }},
-
-                { &hf_cdp_tlvlength,
-                { "Length",		"cdp.tlv.len", FT_UINT16, BASE_DEC, NULL, 0x0,
-			"" }},
-        };
-	static gint *ett[] = {
-		&ett_cdp,
-		&ett_cdp_tlv,
-		&ett_cdp_address,
-		&ett_cdp_capabilities,
-	};
-
-        proto_cdp = proto_register_protocol("Cisco Discovery Protocol", "cdp");
-        proto_register_field_array(proto_cdp, hf, array_length(hf));
-	proto_register_subtree_array(ett, array_length(ett));
+    static hf_register_info hf[] = {
+	{ &hf_cdp_version,
+	{ "Version",		"cdp.version",  FT_UINT8, BASE_DEC, NULL, 0x0,
+	  "" }},
+
+	{ &hf_cdp_ttl,
+	{ "TTL",		"cdp.ttl", FT_UINT16, BASE_DEC, NULL, 0x0,
+	  "" }},
+
+	{ &hf_cdp_checksum,
+	{ "Checksum",		"cdp.checksum", FT_UINT16, BASE_HEX, NULL, 0x0,
+	  "" }},
+
+	{ &hf_cdp_tlvtype,
+	{ "Type",		"cdp.tlv.type", FT_UINT16, BASE_HEX, VALS(type_vals), 0x0,
+	  "" }},
+
+	{ &hf_cdp_tlvlength,
+	{ "Length",		"cdp.tlv.len", FT_UINT16, BASE_DEC, NULL, 0x0,
+	  "" }},
+    };
+    static gint *ett[] = {
+	&ett_cdp,
+	&ett_cdp_tlv,
+	&ett_cdp_address,
+	&ett_cdp_capabilities,
+    };
+
+    proto_cdp = proto_register_protocol("Cisco Discovery Protocol", "cdp");
+    proto_register_field_array(proto_cdp, hf, array_length(hf));
+    proto_register_subtree_array(ett, array_length(ett));
+}
+
+void
+proto_reg_handoff_cdp(void)
+{
+    dissector_add("llc.cisco_pid", 0x2000, dissect_cdp);
 }