2004-12-01 12:41:43 +00:00
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/* packet-bittorrent.c
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* Routines for bittorrent packet dissection
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* Copyright (C) 2004 Jelmer Vernooij <jelmer@samba.org>
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*
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* $Id$
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@ethereal.com>
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* Copyright 1998 Gerald Combs
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*
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* Copied from packet-pop.c
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <stdio.h>
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#include <string.h>
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#include <glib.h>
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#include <epan/prefs.h>
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#include <epan/conversation.h>
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#include <epan/packet.h>
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#include <epan/strutil.h>
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#include "packet-tcp.h"
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2004-12-03 20:51:10 +00:00
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/*
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* See
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*
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* http://bittorrent.com/protocol.html
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*/
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2004-12-01 12:41:43 +00:00
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#define BITTORRENT_MESSAGE_CHOKE 0
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#define BITTORRENT_MESSAGE_UNCHOKE 1
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#define BITTORRENT_MESSAGE_INTERESTED 2
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#define BITTORRENT_MESSAGE_NOT_INTERESTED 3
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#define BITTORRENT_MESSAGE_HAVE 4
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#define BITTORRENT_MESSAGE_BITFIELD 5
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#define BITTORRENT_MESSAGE_REQUEST 6
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#define BITTORRENT_MESSAGE_PIECE 7
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#define BITTORRENT_MESSAGE_CANCEL 8
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static const value_string bittorrent_messages[] = {
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{ BITTORRENT_MESSAGE_CHOKE, "Choke" },
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{ BITTORRENT_MESSAGE_UNCHOKE, "Unchoke" },
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{ BITTORRENT_MESSAGE_INTERESTED, "Interested" },
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{ BITTORRENT_MESSAGE_NOT_INTERESTED, "Not Interested" },
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{ BITTORRENT_MESSAGE_HAVE, "Have" },
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{ BITTORRENT_MESSAGE_BITFIELD, "Bitfield" },
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{ BITTORRENT_MESSAGE_REQUEST, "Request" },
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{ BITTORRENT_MESSAGE_PIECE, "Piece" },
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{ BITTORRENT_MESSAGE_CANCEL, "Cancel" },
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{ 0, NULL }
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};
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static int proto_bittorrent = -1;
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static gint hf_bittorrent_field_length = -1;
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static gint hf_bittorrent_prot_name_len = -1;
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static gint hf_bittorrent_prot_name = -1;
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static gint hf_bittorrent_reserved = -1;
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static gint hf_bittorrent_sha1_hash = -1;
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static gint hf_bittorrent_peer_id = -1;
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static gint hf_bittorrent_msg_len = -1;
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static gint hf_bittorrent_msg_type = -1;
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static gint hf_bittorrent_bitfield_data = -1;
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static gint hf_bittorrent_piece_index = -1;
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static gint hf_bittorrent_piece_begin = -1;
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static gint hf_bittorrent_piece_length = -1;
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static gint hf_bittorrent_piece_data = -1;
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static gint ett_bittorrent = -1;
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static gint ett_bittorrent_msg = -1;
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static gboolean bittorrent_desegment = TRUE;
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2005-07-09 00:44:44 +00:00
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static dissector_handle_t bittorrent_handle;
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2004-12-01 12:41:43 +00:00
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static guint get_bittorrent_pdu_length(tvbuff_t *tvb, int offset)
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{
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if (tvb_get_guint8(tvb, offset) == 19) {
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return 20 + 20 + 20 + 8;
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} else {
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guint32 length = tvb_get_ntohl(tvb, offset);
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return 4 + length;
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}
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}
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static void dissect_bittorrent_message (tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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int offset = 0;
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proto_tree *mtree;
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guint8 type;
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guint32 length = tvb_get_ntohl(tvb, offset);
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proto_item *ti = proto_tree_add_text(tree, tvb, offset, length, "BitTorrent Message");
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mtree = proto_item_add_subtree(ti, ett_bittorrent_msg);
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proto_tree_add_item(mtree, hf_bittorrent_msg_len, tvb, offset, 4, FALSE); offset+=4;
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/* Keepalive message */
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if (length == 0) {
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if (check_col(pinfo->cinfo, COL_INFO)) {
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col_set_str(pinfo->cinfo, COL_INFO, "BitTorrent KeepAlive message");
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}
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return;
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}
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type = tvb_get_guint8(tvb, offset);
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proto_tree_add_item(mtree, hf_bittorrent_msg_type, tvb, offset, 1, FALSE); offset+=1;
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2005-06-26 19:56:52 +00:00
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if (check_col(pinfo->cinfo, COL_INFO)) {
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const char *val = match_strval(type, bittorrent_messages);
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2004-12-01 12:41:43 +00:00
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if (val != NULL) {
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col_set_str(pinfo->cinfo, COL_INFO, val);
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}
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}
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switch (type)
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{
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case BITTORRENT_MESSAGE_CHOKE:
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case BITTORRENT_MESSAGE_UNCHOKE:
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case BITTORRENT_MESSAGE_INTERESTED:
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case BITTORRENT_MESSAGE_NOT_INTERESTED:
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/* No payload */
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break;
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case BITTORRENT_MESSAGE_REQUEST:
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case BITTORRENT_MESSAGE_CANCEL:
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proto_tree_add_item(mtree, hf_bittorrent_piece_index, tvb, offset, 4, FALSE); offset += 4;
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proto_tree_add_item(mtree, hf_bittorrent_piece_begin, tvb, offset, 4, FALSE); offset += 4;
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proto_tree_add_item(mtree, hf_bittorrent_piece_length, tvb, offset, 4, FALSE);
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break;
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case BITTORRENT_MESSAGE_HAVE:
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proto_tree_add_item(mtree, hf_bittorrent_piece_index, tvb, offset, 4, FALSE);
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break;
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case BITTORRENT_MESSAGE_BITFIELD:
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proto_tree_add_item(mtree, hf_bittorrent_bitfield_data, tvb, offset, tvb_length_remaining(tvb, offset), FALSE);
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break;
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case BITTORRENT_MESSAGE_PIECE:
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proto_tree_add_item(mtree, hf_bittorrent_piece_index, tvb, offset, 4, FALSE); offset += 4;
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proto_tree_add_item(mtree, hf_bittorrent_piece_begin, tvb, offset, 4, FALSE); offset += 4;
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proto_tree_add_item(mtree, hf_bittorrent_piece_data, tvb, offset, tvb_length_remaining(tvb, offset), FALSE);
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break;
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}
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}
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static void dissect_bittorrent_welcome (tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
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{
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int offset = 0;
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2005-07-09 00:44:44 +00:00
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2004-12-01 12:41:43 +00:00
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if (check_col(pinfo->cinfo, COL_INFO)) {
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col_set_str(pinfo->cinfo, COL_INFO, "BitTorrent Handshake");
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}
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proto_tree_add_item(tree, hf_bittorrent_prot_name_len, tvb, offset, 1, FALSE); offset+=1;
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proto_tree_add_item(tree, hf_bittorrent_prot_name, tvb, offset, 19, FALSE); offset += 19;
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proto_tree_add_item(tree, hf_bittorrent_reserved, tvb, offset, 8, FALSE); offset += 8;
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proto_tree_add_item(tree, hf_bittorrent_sha1_hash, tvb, offset, 20, FALSE); offset += 20;
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proto_tree_add_item(tree, hf_bittorrent_peer_id, tvb, offset, 20, FALSE); offset += 20;
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}
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static void dissect_bittorrent_tcp_pdu (tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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proto_item *ti;
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2005-07-09 00:44:44 +00:00
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if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "BitTorrent");
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}
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2004-12-01 12:41:43 +00:00
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2005-07-09 00:44:44 +00:00
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if (check_col(pinfo->cinfo, COL_INFO)) {
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2004-12-01 12:41:43 +00:00
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col_set_str(pinfo->cinfo, COL_INFO, "BitTorrent Peer-To-Peer connection");
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}
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ti = proto_tree_add_text(tree, tvb, 0, -1, "BitTorrent");
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tree = proto_item_add_subtree(ti, ett_bittorrent);
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if (tvb_get_guint8(tvb, 0) == 19) {
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dissect_bittorrent_welcome(tvb, pinfo, tree);
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} else {
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dissect_bittorrent_message(tvb, pinfo, tree);
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}
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}
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static void dissect_bittorrent (tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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tcp_dissect_pdus(tvb, pinfo, tree, bittorrent_desegment, 4, get_bittorrent_pdu_length, dissect_bittorrent_tcp_pdu);
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}
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2005-07-09 00:44:44 +00:00
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static const guint8 bittorrent_magic[20] = {
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19,
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'B', 'i', 't', 'T', 'o', 'r', 'r', 'e', 'n', 't',
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' ', 'p', 'r', 'o', 't', 'o', 'c', 'o', 'l'
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};
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2004-12-01 12:41:43 +00:00
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static gboolean test_bittorrent_packet (tvbuff_t *tvb, packet_info *pinfo,
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proto_tree *tree)
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{
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conversation_t *conversation;
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2005-07-09 00:44:44 +00:00
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if (tvb_memeql(tvb, 0, bittorrent_magic, sizeof bittorrent_magic) == -1) {
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2004-12-01 12:41:43 +00:00
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return FALSE;
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}
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2005-02-02 20:07:03 +00:00
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conversation = conversation_new (pinfo->fd->num, &pinfo->src, &pinfo->dst, pinfo->ptype, pinfo->srcport, pinfo->destport, 0);
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2004-12-01 12:41:43 +00:00
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2005-07-09 00:44:44 +00:00
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conversation_set_dissector(conversation, bittorrent_handle);
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2004-12-01 12:41:43 +00:00
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dissect_bittorrent(tvb, pinfo, tree);
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return TRUE;
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}
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void
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proto_register_bittorrent(void)
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{
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static hf_register_info hf[] = {
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{ &hf_bittorrent_field_length,
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{ "Field Length", "bittorrent.length", FT_UINT32, BASE_DEC, NULL, 0x0, "", HFILL },
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},
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{ &hf_bittorrent_prot_name_len,
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{ "Protocol Name Length", "bittorrent.protocol.name.length", FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL },
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},
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{ &hf_bittorrent_prot_name,
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{ "Protocol Name", "bittorrent.protocol.name", FT_STRING, BASE_DEC, NULL, 0x0, "", HFILL },
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},
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{ &hf_bittorrent_reserved,
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{ "Reserved Extension Bytes", "bittorrent.reserved", FT_BYTES, BASE_DEC, NULL, 0x0, "", HFILL },
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},
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{ &hf_bittorrent_sha1_hash,
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{ "SHA1 Hash of info dictionary", "bittorrent.info_hash", FT_BYTES, BASE_DEC, NULL, 0x0, "", HFILL },
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},
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{ &hf_bittorrent_peer_id,
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{ "Peer ID", "bittorrent.peer_id", FT_BYTES, BASE_DEC, NULL, 0x0, "", HFILL },
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},
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{ &hf_bittorrent_msg_len,
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{ "Message Length", "bittorrent.msg.length", FT_UINT32, BASE_HEX, NULL, 0x0, "", HFILL },
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},
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{ &hf_bittorrent_msg_type,
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{ "Message Type", "bittorrent.msg.type", FT_UINT8, BASE_HEX, VALS(bittorrent_messages), 0x0, "", HFILL },
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},
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{ &hf_bittorrent_bitfield_data,
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{ "Bitfield data", "bittorrent.msg.bitfield", FT_BYTES, BASE_HEX, NULL, 0x0, "", HFILL },
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},
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{ &hf_bittorrent_piece_index,
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{ "Piece index", "bittorrent.piece.index", FT_UINT32, BASE_HEX, NULL, 0x0, "", HFILL },
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},
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{ &hf_bittorrent_piece_begin,
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{ "Begin offset of piece", "bittorrent.piece.begin", FT_UINT32, BASE_HEX, NULL, 0x0, "", HFILL },
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},
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{ &hf_bittorrent_piece_data,
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{ "Data in a piece", "bittorrent.piece.data", FT_BYTES, BASE_HEX, NULL, 0x0, "", HFILL },
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},
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{ &hf_bittorrent_piece_length,
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{ "Piece Length", "bittorrent.piece.length", FT_UINT32, BASE_HEX, NULL, 0x0, "", HFILL },
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},
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};
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static gint *ett[] = {
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&ett_bittorrent,
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&ett_bittorrent_msg,
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};
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module_t *bittorrent_module;
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proto_bittorrent = proto_register_protocol("BitTorrent", "BitTorrent", "bittorrent");
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proto_register_field_array(proto_bittorrent, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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bittorrent_module = prefs_register_protocol(proto_bittorrent, NULL);
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prefs_register_bool_preference(bittorrent_module, "desegment",
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"Reassemble BitTorrent messages spanning multiple TCP segments",
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"Whether the BitTorrent dissector should reassemble messages spanning multiple TCP segments."
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" To use this option, you must also enable \"Allow subdissectors to reassemble TCP streams\" in the TCP protocol settings.",
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&bittorrent_desegment);
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}
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void
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proto_reg_handoff_bittorrent(void)
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{
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register_dissector("bittorrent", dissect_bittorrent, proto_bittorrent);
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2005-07-09 00:44:44 +00:00
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bittorrent_handle = find_dissector("bittorrent");
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2004-12-01 12:41:43 +00:00
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heur_dissector_add("tcp", test_bittorrent_packet, proto_bittorrent);
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}
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