From Peter Johansson: add an option to decode the client information,

and check the validity of messages a bit more carefully.

Reformat a bit so not as much code is missed by those of us who like
narrow editor windows.


git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@15369 f5534014-38df-0310-8fa8-9805f1628bb7

1 files changed, 286 insertions, 190 deletions

diff --git a/epan/dissectors/packet-bittorrent.c b/epan/dissectors/packet-bittorrent.c
index e57d13928e..d3021a8832 100644
--- a/epan/dissectors/packet-bittorrent.c
+++ b/epan/dissectors/packet-bittorrent.c
@@ -43,246 +43,339 @@
 /*
  * See
  *
- *	http://bittorrent.com/protocol.html
+ * http://bittorrent.com/protocol.html
+ * http://wiki.theory.org/BitTorrentSpecification
+ * http://bitconjurer.org/BitTorrent/protocol.html
  */
 
-#define BITTORRENT_MESSAGE_CHOKE			0
-#define BITTORRENT_MESSAGE_UNCHOKE			1
-#define BITTORRENT_MESSAGE_INTERESTED		2
-#define BITTORRENT_MESSAGE_NOT_INTERESTED	3
-#define BITTORRENT_MESSAGE_HAVE				4
-#define BITTORRENT_MESSAGE_BITFIELD			5
-#define BITTORRENT_MESSAGE_REQUEST			6
-#define BITTORRENT_MESSAGE_PIECE			7
-#define BITTORRENT_MESSAGE_CANCEL			8
+#define BITTORRENT_MESSAGE_CHOKE          0
+#define BITTORRENT_MESSAGE_UNCHOKE        1
+#define BITTORRENT_MESSAGE_INTERESTED     2
+#define BITTORRENT_MESSAGE_NOT_INTERESTED 3
+#define BITTORRENT_MESSAGE_HAVE           4
+#define BITTORRENT_MESSAGE_BITFIELD       5
+#define BITTORRENT_MESSAGE_REQUEST        6
+#define BITTORRENT_MESSAGE_PIECE          7
+#define BITTORRENT_MESSAGE_CANCEL         8
+
+#define BITTORRENT_HEADER_LENGTH          4
 
 static const value_string bittorrent_messages[] = {
-	{ BITTORRENT_MESSAGE_CHOKE, "Choke" },
-	{ BITTORRENT_MESSAGE_UNCHOKE, "Unchoke" },
-	{ BITTORRENT_MESSAGE_INTERESTED, "Interested" },
-	{ BITTORRENT_MESSAGE_NOT_INTERESTED, "Not Interested" },
-	{ BITTORRENT_MESSAGE_HAVE, "Have" },
-	{ BITTORRENT_MESSAGE_BITFIELD, "Bitfield" },
-	{ BITTORRENT_MESSAGE_REQUEST, "Request" },
-	{ BITTORRENT_MESSAGE_PIECE, "Piece" },
-	{ BITTORRENT_MESSAGE_CANCEL, "Cancel" },
-	{ 0, NULL }
+   { BITTORRENT_MESSAGE_CHOKE, "Choke" },
+   { BITTORRENT_MESSAGE_UNCHOKE, "Unchoke" },
+   { BITTORRENT_MESSAGE_INTERESTED, "Interested" },
+   { BITTORRENT_MESSAGE_NOT_INTERESTED, "Not Interested" },
+   { BITTORRENT_MESSAGE_HAVE, "Have" },
+   { BITTORRENT_MESSAGE_BITFIELD, "Bitfield" },
+   { BITTORRENT_MESSAGE_REQUEST, "Request" },
+   { BITTORRENT_MESSAGE_PIECE, "Piece" },
+   { BITTORRENT_MESSAGE_CANCEL, "Cancel" },
+   { 0, NULL }
 };
 
+static dissector_handle_t dissector_handle;
 static int proto_bittorrent = -1;
 
 static gint hf_bittorrent_field_length  = -1;
 static gint hf_bittorrent_prot_name_len = -1;
 static gint hf_bittorrent_prot_name     = -1;
-static gint hf_bittorrent_reserved 		= -1;
-static gint hf_bittorrent_sha1_hash		= -1;
-static gint hf_bittorrent_peer_id 		= -1;
-static gint hf_bittorrent_msg_len		= -1;
-static gint hf_bittorrent_msg_type		= -1;
-static gint hf_bittorrent_bitfield_data	= -1;
-static gint hf_bittorrent_piece_index	= -1;
-static gint hf_bittorrent_piece_begin	= -1;
-static gint hf_bittorrent_piece_length	= -1;
-static gint hf_bittorrent_piece_data	= -1;
+static gint hf_bittorrent_reserved      = -1;
+static gint hf_bittorrent_sha1_hash     = -1;
+static gint hf_bittorrent_peer_id       = -1;
+static gint hf_bittorrent_msg_len       = -1;
+static gint hf_bittorrent_msg_type      = -1;
+static gint hf_bittorrent_bitfield_data = -1;
+static gint hf_bittorrent_piece_index   = -1;
+static gint hf_bittorrent_piece_begin   = -1;
+static gint hf_bittorrent_piece_length  = -1;
+static gint hf_bittorrent_piece_data    = -1;
 
 static gint ett_bittorrent = -1;
 static gint ett_bittorrent_msg = -1;
+static gint ett_peer_id = -1;
 
 static gboolean bittorrent_desegment = TRUE;
+static gboolean decode_client_information = FALSE;
+
+struct client_information {
+   char id[4];
+   char *name;
+};
 
-static dissector_handle_t bittorrent_handle;
+static struct client_information peer_id[] = {
+   {"-AZ", "Azureus"},
+   {"-BB", "BitBuddy"},
+   {"-CT", "CTorrent"},
+   {"-MT", "MoonlightTorrent"},
+   {"-LT", "libtorrent"},
+   {"-BX", "Bittorrent X"},
+   {"-TS", "Torrentstorm"},
+   {"-TN", "TorrnetDotNET"},
+   {"-SS", "SwarmScope"},
+   {"-XT", "XanTorrent"},
+   {"-BS", "BTSlave"},
+   {"-ZT", "ZipTorrent"},
+   {"S",   "Shadow's client"},
+   {"U",   "UPnP NAT Bit Torrent"},
+   {"T",   "BitTornado"},
+   {"A",   "ABC"},
+   {"",    NULL}
+};
 
 static guint get_bittorrent_pdu_length(tvbuff_t *tvb, int offset)
 {
-	if (tvb_get_guint8(tvb, offset) == 19) {
-		return 20 + 20 + 20 + 8;
-	} else {
-		guint32 length = tvb_get_ntohl(tvb, offset);
-		return 4 + length;
-	}
+   guint8 type;
+   guint32 length;
+
+   if (tvb_get_guint8(tvb, offset) == 19 &&
+       tvb_memeql(tvb, offset + 1, "BitTorrent protocol", 19) == 0) {
+      /* Return the length of a Handshake message */
+      return 1 + /* pstrlen */
+         19 +    /* pstr */
+         8 +     /* reserved */
+         20 +    /* SHA1 hash of the info key */
+         20;     /* peer id */
+   } else {
+      /* Try to validate the length of the message indicated by the header. */
+      length = tvb_get_ntohl(tvb, offset);
+      if(length == 0) {
+        /* keep-alive - no message ID */
+        return BITTORRENT_HEADER_LENGTH;
+      }
+      /* Do some sanity checking of the message, if we have the ID byte */
+      if(tvb_offset_exists(tvb, offset + BITTORRENT_HEADER_LENGTH)) {
+         type = tvb_get_guint8(tvb, offset + BITTORRENT_HEADER_LENGTH);
+         if(type <= BITTORRENT_MESSAGE_CANCEL) {
+            /* This seems to be a valid BitTorrent header with a known
+               type identifier */
+            return BITTORRENT_HEADER_LENGTH + length;
+         } else {
+            /* The type is not known, this message cannot be decoded
+               properly by this dissector. */
+            /* XXX - what we want to do here is to just dissect the rest
+               of this TCP segment as "continuation data"; if this is
+               a real BitTorrent connection, we probably didn't get some
+               data before this segment. */
+            DISSECTOR_ASSERT(!"Reassemble error?");
+            return 0;
+         }
+      } else {
+         /* For now, we just give up, so we don't end up dissecting
+            a message with a bogus length. */
+         DISSECTOR_ASSERT(!"Reassemble error?");
+         return 0;
+      }
+   }
 }
 
 static void dissect_bittorrent_message (tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 {
-	int offset = 0;
-	proto_tree *mtree;
-	guint8 type;
-	guint32 length = tvb_get_ntohl(tvb, offset);
-	proto_item *ti = proto_tree_add_text(tree, tvb, offset, length, "BitTorrent Message");
-
-	mtree = proto_item_add_subtree(ti, ett_bittorrent_msg);
-								  
-	proto_tree_add_item(mtree, hf_bittorrent_msg_len, tvb, offset, 4, FALSE); offset+=4;
-
-	/* Keepalive message */
-	if (length == 0) {
-	    if (check_col(pinfo->cinfo, COL_INFO)) {
-		    col_set_str(pinfo->cinfo, COL_INFO, "BitTorrent KeepAlive message");
-		}
-		return;
-	}
-	
-	type = tvb_get_guint8(tvb, offset);
-	proto_tree_add_item(mtree, hf_bittorrent_msg_type, tvb, offset, 1, FALSE); offset+=1;
-
-	if (check_col(pinfo->cinfo, COL_INFO)) {
-		const char *val = match_strval(type, bittorrent_messages);
-		if (val != NULL) {
-		    col_set_str(pinfo->cinfo, COL_INFO, val);
-		}
-	}
-
-	switch (type) 
-	{
-	case BITTORRENT_MESSAGE_CHOKE:
-	case BITTORRENT_MESSAGE_UNCHOKE:
-	case BITTORRENT_MESSAGE_INTERESTED:
-	case BITTORRENT_MESSAGE_NOT_INTERESTED:
-		/* No payload */
-		break;
-		
-
-	case BITTORRENT_MESSAGE_REQUEST:
-	case BITTORRENT_MESSAGE_CANCEL:
-		proto_tree_add_item(mtree, hf_bittorrent_piece_index, tvb, offset, 4, FALSE); offset += 4;
-		proto_tree_add_item(mtree, hf_bittorrent_piece_begin, tvb, offset, 4, FALSE); offset += 4;
-		proto_tree_add_item(mtree, hf_bittorrent_piece_length, tvb, offset, 4, FALSE);
-		break;
-		
-	case BITTORRENT_MESSAGE_HAVE:
-		proto_tree_add_item(mtree, hf_bittorrent_piece_index, tvb, offset, 4, FALSE);
-		break;
-		
-	case BITTORRENT_MESSAGE_BITFIELD:
-		proto_tree_add_item(mtree, hf_bittorrent_bitfield_data, tvb, offset, tvb_length_remaining(tvb, offset), FALSE); 
-		break;
-		
-	case BITTORRENT_MESSAGE_PIECE:
-		proto_tree_add_item(mtree, hf_bittorrent_piece_index, tvb, offset, 4, FALSE); offset += 4;
-		proto_tree_add_item(mtree, hf_bittorrent_piece_begin, tvb, offset, 4, FALSE); offset += 4;
-		proto_tree_add_item(mtree, hf_bittorrent_piece_data, tvb, offset, tvb_length_remaining(tvb, offset), FALSE);
-		break;
-	}
+   int offset = 0;
+   proto_tree *mtree;
+   guint8 type;
+   guint32 length;
+   proto_item *ti;
+
+   length = tvb_get_ntohl(tvb, offset);
+   ti = proto_tree_add_text(tree, tvb, offset, length + BITTORRENT_HEADER_LENGTH, "BitTorrent Message");
+   mtree = proto_item_add_subtree(ti, ett_bittorrent_msg);
+
+   proto_tree_add_item(mtree, hf_bittorrent_msg_len, tvb, offset, BITTORRENT_HEADER_LENGTH, FALSE);
+   offset += BITTORRENT_HEADER_LENGTH;
+
+   /* Keepalive message */
+   if (length == 0) {
+      if (check_col(pinfo->cinfo, COL_INFO)) {
+         col_set_str(pinfo->cinfo, COL_INFO, "BitTorrent KeepAlive message");
+      }
+      return;
+   }
+   
+   type = tvb_get_guint8(tvb, offset);
+   proto_tree_add_item(mtree, hf_bittorrent_msg_type, tvb, offset, 1, FALSE);
+   offset += 1;
+   length -= 1;
+   
+   if (check_col(pinfo->cinfo, COL_INFO)) {
+      col_add_str(pinfo->cinfo, COL_INFO,
+                  val_to_str(type, bittorrent_messages, "Unknown message type %u"));
+   }
+
+   switch (type) {
+   case BITTORRENT_MESSAGE_CHOKE:
+   case BITTORRENT_MESSAGE_UNCHOKE:
+   case BITTORRENT_MESSAGE_INTERESTED:
+   case BITTORRENT_MESSAGE_NOT_INTERESTED:
+      /* No payload */
+      break;
+
+   case BITTORRENT_MESSAGE_REQUEST:
+   case BITTORRENT_MESSAGE_CANCEL:
+      proto_tree_add_item(mtree, hf_bittorrent_piece_index, tvb, offset, 4, FALSE); offset += 4;
+      proto_tree_add_item(mtree, hf_bittorrent_piece_begin, tvb, offset, 4, FALSE); offset += 4;
+      proto_tree_add_item(mtree, hf_bittorrent_piece_length, tvb, offset, 4, FALSE);
+      break;
+
+   case BITTORRENT_MESSAGE_HAVE:
+      proto_tree_add_item(mtree, hf_bittorrent_piece_index, tvb, offset, 4, FALSE);
+      break;
+
+   case BITTORRENT_MESSAGE_BITFIELD:
+      proto_tree_add_item(mtree, hf_bittorrent_bitfield_data, tvb, offset, length, FALSE); 
+      break;
+
+   case BITTORRENT_MESSAGE_PIECE:
+      proto_tree_add_item(mtree, hf_bittorrent_piece_index, tvb, offset, 4, FALSE);
+      offset += 4;
+      length -= 4;
+      proto_tree_add_item(mtree, hf_bittorrent_piece_begin, tvb, offset, 4, FALSE);
+      offset += 4;
+      length -= 4;
+      proto_tree_add_item(mtree, hf_bittorrent_piece_data, tvb, offset, length, FALSE);
+      break;
+
+   default:
+      break;
+   }
 }
 
 static void dissect_bittorrent_welcome (tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
 {
-	int offset = 0;
-
-	if (check_col(pinfo->cinfo, COL_INFO)) {
-	    col_set_str(pinfo->cinfo, COL_INFO, "BitTorrent Handshake");
-	}
-
-	proto_tree_add_item(tree, hf_bittorrent_prot_name_len, tvb, offset, 1, FALSE); offset+=1;
-	proto_tree_add_item(tree, hf_bittorrent_prot_name, tvb, offset, 19, FALSE); offset += 19;
-	proto_tree_add_item(tree, hf_bittorrent_reserved, tvb, offset, 8, FALSE); offset += 8;
-	proto_tree_add_item(tree, hf_bittorrent_sha1_hash, tvb, offset, 20, FALSE); offset += 20;
-	proto_tree_add_item(tree, hf_bittorrent_peer_id, tvb, offset, 20, FALSE); offset += 20;
+   int offset = 0;
+   int i;
+   char *version;
+   
+   if (check_col(pinfo->cinfo, COL_INFO)) {
+      col_set_str(pinfo->cinfo, COL_INFO, "BitTorrent Handshake");
+   }
+   
+   proto_tree_add_item(tree, hf_bittorrent_prot_name_len, tvb, offset, 1, FALSE); offset+=1;
+   proto_tree_add_item(tree, hf_bittorrent_prot_name, tvb, offset, 19, FALSE); offset += 19;
+   proto_tree_add_item(tree, hf_bittorrent_reserved, tvb, offset, 8, FALSE); offset += 8;
+   
+   proto_tree_add_item(tree, hf_bittorrent_sha1_hash, tvb, offset, 20, FALSE);
+   offset += 20;
+
+   proto_tree_add_item(tree, hf_bittorrent_peer_id, tvb, offset, 20, FALSE);
+   if(decode_client_information) {
+      for(i = 0; peer_id[i].id[0] != '\0'; ++i)
+      {
+         if(tvb_memeql(tvb, offset, peer_id[i].id, strlen(peer_id[i].id)) == 0) {
+            /* The version number is 4 numeric characters for the
+               client ids beginning with '-' and 3 characters for the
+               rest. */
+            version = tvb_get_string(tvb, offset + strlen(peer_id[i].id),
+               (peer_id[i].id[0] == '-') ? 4 : 3);
+            proto_tree_add_text(tree, tvb, offset, 20, "Client is %s v%s",
+               peer_id[i].name,
+               format_text(version, (peer_id[i].id[0] == '-') ? 4 : 3));
+            g_free(version);
+            break;
+         }
+      }
+   }
+   offset += 20;
 }
 
 static void dissect_bittorrent_tcp_pdu (tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 {
-	proto_item *ti;
-	
-	if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
-		col_set_str(pinfo->cinfo, COL_PROTOCOL, "BitTorrent");
-	}
-
-	if (check_col(pinfo->cinfo, COL_INFO)) {
-	    col_set_str(pinfo->cinfo, COL_INFO, "BitTorrent Peer-To-Peer connection");
-	}
-
-	ti = proto_tree_add_text(tree, tvb, 0, -1, "BitTorrent");
-
-	tree = proto_item_add_subtree(ti, ett_bittorrent);
-
-	if (tvb_get_guint8(tvb, 0) == 19) {
-		dissect_bittorrent_welcome(tvb, pinfo, tree);
-	} else {
-		dissect_bittorrent_message(tvb, pinfo, tree);
-	}
+   proto_item *ti;
+   
+   if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
+      col_set_str(pinfo->cinfo, COL_PROTOCOL, "BitTorrent");
+   }
+   
+   if (check_col(pinfo->cinfo, COL_INFO)) {
+      col_set_str(pinfo->cinfo, COL_INFO, "BitTorrent Peer-To-Peer connection");
+   }
+   
+   ti = proto_tree_add_text(tree, tvb, 0, -1, "BitTorrent");
+   
+   tree = proto_item_add_subtree(ti, ett_bittorrent);
+   
+   if (tvb_get_guint8(tvb, 0) == 19 &&
+      tvb_memeql(tvb, 1, "BitTorrent protocol", 19) == 0) {
+      dissect_bittorrent_welcome(tvb, pinfo, tree);
+   } else {
+      dissect_bittorrent_message(tvb, pinfo, tree);
+   }
 }
 
 static void dissect_bittorrent (tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 {
-	tcp_dissect_pdus(tvb, pinfo, tree, bittorrent_desegment, 4, get_bittorrent_pdu_length, dissect_bittorrent_tcp_pdu);
+   tcp_dissect_pdus(tvb, pinfo, tree, bittorrent_desegment, BITTORRENT_HEADER_LENGTH,
+                    get_bittorrent_pdu_length, dissect_bittorrent_tcp_pdu);
 }
 
-static const guint8 bittorrent_magic[20] = {
-	19,
-	'B', 'i', 't', 'T', 'o', 'r', 'r', 'e', 'n', 't',
-	' ', 'p', 'r', 'o', 't', 'o', 'c', 'o', 'l'
-};
-
 static gboolean test_bittorrent_packet (tvbuff_t *tvb, packet_info *pinfo,
-										     proto_tree *tree)
+                                        proto_tree *tree)
 {
-	conversation_t *conversation;
+   conversation_t *conversation;
 
-	if (tvb_memeql(tvb, 0, bittorrent_magic, sizeof bittorrent_magic) == -1) {
-		return FALSE;
-	}
+   if (tvb_bytes_exist(tvb, 0, 20) &&
+       tvb_get_guint8(tvb, 0) == 19 &&
+       tvb_memeql(tvb, 1, "BitTorrent protocol", 19) == 0) {
+      conversation = conversation_new (pinfo->fd->num, &pinfo->src, &pinfo->dst, pinfo->ptype, pinfo->srcport, pinfo->destport, 0);
 
-	conversation = conversation_new (pinfo->fd->num, &pinfo->src, &pinfo->dst, pinfo->ptype, pinfo->srcport, pinfo->destport, 0);
+      conversation_set_dissector(conversation, dissector_handle);
 
-	conversation_set_dissector(conversation, bittorrent_handle);
-	
-	dissect_bittorrent(tvb, pinfo, tree);
-
-	return TRUE;
-}
+      dissect_bittorrent(tvb, pinfo, tree);
 
+      return TRUE;
+   }
 
+   return FALSE;
+}
 
 void
 proto_register_bittorrent(void)
 {
-
-  static hf_register_info hf[] = {
-	  { &hf_bittorrent_field_length, 
-		  { "Field Length", "bittorrent.length", FT_UINT32, BASE_DEC, NULL, 0x0, "", HFILL },
-	  },
-	  { &hf_bittorrent_prot_name_len,
-		  { "Protocol Name Length", "bittorrent.protocol.name.length", FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL },
-	  },
-	  { &hf_bittorrent_prot_name,
-		  { "Protocol Name", "bittorrent.protocol.name", FT_STRING, BASE_DEC, NULL, 0x0, "", HFILL },
-	  },
-	  { &hf_bittorrent_reserved,
-		  { "Reserved Extension Bytes", "bittorrent.reserved", FT_BYTES, BASE_DEC, NULL, 0x0, "", HFILL },
-	  },
-	  { &hf_bittorrent_sha1_hash,
-		  { "SHA1 Hash of info dictionary", "bittorrent.info_hash", FT_BYTES, BASE_DEC, NULL, 0x0, "", HFILL },
-	  },
-	  { &hf_bittorrent_peer_id,
-		  { "Peer ID", "bittorrent.peer_id", FT_BYTES, BASE_DEC, NULL, 0x0, "", HFILL },
-	  },
-	  { &hf_bittorrent_msg_len,
-		  { "Message Length", "bittorrent.msg.length", FT_UINT32, BASE_HEX, NULL, 0x0, "", HFILL },
-	  }, 
-	  { &hf_bittorrent_msg_type,
-		  { "Message Type", "bittorrent.msg.type", FT_UINT8, BASE_HEX, VALS(bittorrent_messages), 0x0, "", HFILL },
-	  },
-	  { &hf_bittorrent_bitfield_data,
-		  { "Bitfield data", "bittorrent.msg.bitfield", FT_BYTES, BASE_HEX, NULL, 0x0, "", HFILL },
-	  },
-	  { &hf_bittorrent_piece_index,
-		  { "Piece index", "bittorrent.piece.index", FT_UINT32, BASE_HEX, NULL, 0x0, "", HFILL },
-	  },
-	  { &hf_bittorrent_piece_begin,
-		  { "Begin offset of piece", "bittorrent.piece.begin", FT_UINT32, BASE_HEX, NULL, 0x0, "", HFILL },
-	  },
-	  { &hf_bittorrent_piece_data, 
-		  { "Data in a piece", "bittorrent.piece.data", FT_BYTES, BASE_HEX, NULL, 0x0, "", HFILL },
-	  },
-	  { &hf_bittorrent_piece_length,
-		  { "Piece Length", "bittorrent.piece.length", FT_UINT32, BASE_HEX, NULL, 0x0, "", HFILL },
-	  },
+   static hf_register_info hf[] = {
+      { &hf_bittorrent_field_length, 
+      { "Field Length", "bittorrent.length", FT_UINT32, BASE_DEC, NULL, 0x0, "", HFILL }
+      },
+      { &hf_bittorrent_prot_name_len,
+      { "Protocol Name Length", "bittorrent.protocol.name.length", FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }
+      },
+      { &hf_bittorrent_prot_name,
+      { "Protocol Name", "bittorrent.protocol.name", FT_STRING, BASE_DEC, NULL, 0x0, "", HFILL }
+      },
+      { &hf_bittorrent_reserved,
+      { "Reserved Extension Bytes", "bittorrent.reserved", FT_BYTES, BASE_DEC, NULL, 0x0, "", HFILL }
+      },
+      { &hf_bittorrent_sha1_hash,
+      { "SHA1 Hash of info dictionary", "bittorrent.info_hash", FT_BYTES, BASE_DEC, NULL, 0x0, "", HFILL }
+      },
+      { &hf_bittorrent_peer_id,
+      { "Peer ID", "bittorrent.peer_id", FT_BYTES, BASE_DEC, NULL, 0x0, "", HFILL }
+      },
+      { &hf_bittorrent_msg_len,
+      { "Message Length", "bittorrent.msg.length", FT_UINT32, BASE_DEC, NULL, 0x0, "", HFILL }
+      }, 
+      { &hf_bittorrent_msg_type,
+      { "Message Type", "bittorrent.msg.type", FT_UINT8, BASE_DEC, VALS(bittorrent_messages), 0x0, "", HFILL }
+      },
+      { &hf_bittorrent_bitfield_data,
+      { "Bitfield data", "bittorrent.msg.bitfield", FT_BYTES, BASE_HEX, NULL, 0x0, "", HFILL }
+      },
+      { &hf_bittorrent_piece_index,
+      { "Piece index", "bittorrent.piece.index", FT_UINT32, BASE_HEX, NULL, 0x0, "", HFILL }
+      },
+      { &hf_bittorrent_piece_begin,
+      { "Begin offset of piece", "bittorrent.piece.begin", FT_UINT32, BASE_HEX, NULL, 0x0, "", HFILL }
+      },
+      { &hf_bittorrent_piece_data, 
+      { "Data in a piece", "bittorrent.piece.data", FT_BYTES, BASE_HEX, NULL, 0x0, "", HFILL }
+      },
+      { &hf_bittorrent_piece_length,
+         { "Piece Length", "bittorrent.piece.length", FT_UINT32, BASE_HEX, NULL, 0x0, "", HFILL }
+      }
   };
 
   static gint *ett[] = {
     &ett_bittorrent,
-	&ett_bittorrent_msg,
+    &ett_bittorrent_msg,
+    &ett_peer_id
   };
 
   module_t *bittorrent_module;
@@ -297,13 +390,16 @@ proto_register_bittorrent(void)
     "Whether the BitTorrent dissector should reassemble messages spanning multiple TCP segments."
     " To use this option, you must also enable \"Allow subdissectors to reassemble TCP streams\" in the TCP protocol settings.",
     &bittorrent_desegment);
+  prefs_register_bool_preference(bittorrent_module, "decode_client",
+     "Decode the peer_id of the handshake messages",
+     "Enabling this will tell which BitTorrent client that produced the handshake message",
+     &decode_client_information);
 }
 
 
 void
 proto_reg_handoff_bittorrent(void)
 {
-	register_dissector("bittorrent", dissect_bittorrent, proto_bittorrent);
-	bittorrent_handle = find_dissector("bittorrent");
-  	heur_dissector_add("tcp", test_bittorrent_packet, proto_bittorrent);
+   dissector_handle = create_dissector_handle(dissect_bittorrent, proto_bittorrent);
+   heur_dissector_add("tcp", test_bittorrent_packet, proto_bittorrent);
 }