b90196f28a
There's another extension type used in the uTorrent Transport Protocol. https://github.com/arvidn/libtorrent/blob/master/include/libtorrent/close_reason.hpp Simplify the extension handling a bit by consolidating redundant code.
1326 lines
43 KiB
C
1326 lines
43 KiB
C
/* packet-bt-utp.c
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* Routines for BT-UTP dissection
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* Copyright 2011, Xiao Xiangquan <xiaoxiangquan@gmail.com>
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* Copyright 2021, John Thacker <johnthacker@gmail.com>
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1999 Gerald Combs
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "config.h"
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#include <epan/packet.h>
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#include <epan/conversation.h>
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#include <epan/exceptions.h>
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#include <epan/show_exception.h>
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#include <epan/expert.h>
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#include <epan/prefs.h>
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#include <epan/proto_data.h>
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#include <epan/reassemble.h>
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#include "packet-udp.h"
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#include "packet-bt-utp.h"
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void proto_register_bt_utp(void);
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void proto_reg_handoff_bt_utp(void);
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enum {
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ST_DATA = 0,
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ST_FIN = 1,
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ST_STATE = 2,
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ST_RESET = 3,
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ST_SYN = 4,
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ST_NUM_STATES
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};
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/* V0 hdr: "flags"; V1 hdr: "type" */
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static const value_string bt_utp_type_vals[] = {
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{ ST_DATA, "Data" },
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{ ST_FIN, "Fin" },
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{ ST_STATE, "State" },
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{ ST_RESET, "Reset" },
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{ ST_SYN, "Syn" },
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{ 0, NULL }
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};
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enum {
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EXT_NO_EXTENSION = 0,
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EXT_SELECTIVE_ACKS = 1,
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EXT_EXTENSION_BITS = 2,
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EXT_CLOSE_REASON = 3,
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EXT_NUM_EXT
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};
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static const value_string bt_utp_extension_type_vals[] = {
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{ EXT_NO_EXTENSION, "No Extension" },
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{ EXT_SELECTIVE_ACKS, "Selective ACKs" },
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{ EXT_EXTENSION_BITS, "Extension bits" },
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{ EXT_CLOSE_REASON, "Close reason" },
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{ 0, NULL }
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};
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/* https://github.com/arvidn/libtorrent/blob/master/include/libtorrent/close_reason.hpp */
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static const value_string bt_utp_close_reason_vals[] = {
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{ 0, "None" },
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{ 1, "Duplicate peer ID" },
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{ 2, "Torrent removed" },
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{ 3, "Memory allocation failed" },
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{ 4, "Port blocked" },
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{ 5, "Address blocked" },
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{ 6, "Upload to upload" },
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{ 7, "Not interested upload only" },
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{ 8, "Timeout" },
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{ 9, "Timeout: interest" },
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{ 10, "Timeout: activity" },
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{ 11, "Timeout: handshake" },
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{ 12, "Timeout: request" },
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{ 13, "Protocol blocked" },
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{ 14, "Peer churn" },
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{ 15, "Too many connections" },
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{ 16, "Too many files" },
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/* Reasons caused by the peer sending unexpected data are 256 and up */
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{256, "Encryption error" },
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{257, "Invalid info hash" },
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{258, "Self connection" },
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{259, "Invalid metadata" },
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{260, "Metadata too big" },
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{261, "Message too big" },
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{262, "Invalid message id" },
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{263, "Invalid message" },
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{264, "Invalid piece message" },
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{265, "Invalid have message" },
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{266, "Invalid bitfield message" },
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{267, "Invalid choke message" },
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{268, "Invalid unchoke message" },
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{269, "Invalid interested message" },
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{270, "Invalid not interested message" },
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{271, "Invalid request message" },
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{272, "Invalid reject message" },
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{273, "Invalid allow fast message" },
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{274, "Invalid extended message" },
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{275, "Invalid cancel message" },
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{276, "Invalid DHT port message" },
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{277, "Invalid suggest message" },
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{278, "Invalid have all message" },
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{279, "Invalid don't have message" },
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{280, "Invalid PEX message" },
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{281, "Invalid metadata request message" },
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{282, "Invalid metadata message" },
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{283, "Invalid metadata offset" },
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{284, "Request when choked" },
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{285, "Corrupt pieces" },
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{286, "PEX message too big" },
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{287, "PEX too frequent" },
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{ 0, NULL }
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};
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static int proto_bt_utp = -1;
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/* --- "Original" uTP Header ("version 0" ?) --------------
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See utp.cpp source code @ https://github.com/bittorrent/libutp
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-- Fixed Header --
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0 4 8 16 24 32
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+-------+-------+---------------+---------------+---------------+
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| connection_id |
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+-------+-------+---------------+---------------+---------------+
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| timestamp_seconds |
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+---------------+---------------+---------------+---------------+
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| timestamp_microseconds |
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+---------------+---------------+---------------+---------------+
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| timestamp_difference_microseconds |
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+---------------+---------------+---------------+---------------+
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| wnd_size | ext | flags | seq_nr [ho] |
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+---------------+---------------+---------------+---------------+
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| seq_nr [lo] | ack_nr |
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+---------------+---------------+---------------+
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-- Extension Field(s) --
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0 8 16
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+---------------+---------------+---------------+---------------+
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| extension | len | bitmask
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+---------------+---------------+---------------+---------------+
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+---------------+---------------+....
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*/
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/* --- Version 1 Header ----------------
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Specifications: BEP-0029
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http://www.bittorrent.org/beps/bep_0029.html
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-- Fixed Header --
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Fields Types
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0 4 8 16 24 32
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+-------+-------+---------------+---------------+---------------+
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| type | ver | extension | connection_id |
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+-------+-------+---------------+---------------+---------------+
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| timestamp_microseconds |
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+---------------+---------------+---------------+---------------+
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| timestamp_difference_microseconds |
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+---------------+---------------+---------------+---------------+
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| wnd_size |
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+---------------+---------------+---------------+---------------+
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| seq_nr | ack_nr |
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+---------------+---------------+---------------+---------------+
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-- Extension Field(s) --
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0 8 16
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+---------------+---------------+---------------+---------------+
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| extension | len | bitmask
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+---------------+---------------+---------------+---------------+
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+---------------+---------------+....
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*/
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#define V0_FIXED_HDR_SIZE 23
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#define V1_FIXED_HDR_SIZE 20
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/* Very early versions of libutp (still used by Transmission) set the max
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* recv window size to 0x00380000, versions from 2013 and later set it to
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* 0x00100000, and some other clients use 0x00040000. This is one of the
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* few possible sources of heuristics.
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*/
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#define V1_MAX_WINDOW_SIZE 0x380000U
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static dissector_handle_t bt_utp_handle;
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static dissector_handle_t bittorrent_handle;
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static int hf_bt_utp_ver = -1;
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static int hf_bt_utp_type = -1;
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static int hf_bt_utp_flags = -1;
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static int hf_bt_utp_extension = -1;
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static int hf_bt_utp_next_extension_type = -1;
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static int hf_bt_utp_extension_len = -1;
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static int hf_bt_utp_extension_bitmask = -1;
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static int hf_bt_utp_extension_close_reason = -1;
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static int hf_bt_utp_extension_unknown = -1;
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static int hf_bt_utp_connection_id_v0 = -1;
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static int hf_bt_utp_connection_id_v1 = -1;
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static int hf_bt_utp_stream = -1;
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static int hf_bt_utp_timestamp_sec = -1;
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static int hf_bt_utp_timestamp_us = -1;
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static int hf_bt_utp_timestamp_diff_us = -1;
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static int hf_bt_utp_wnd_size_v0 = -1;
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static int hf_bt_utp_wnd_size_v1 = -1;
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static int hf_bt_utp_seq_nr = -1;
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static int hf_bt_utp_ack_nr = -1;
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static int hf_bt_utp_len = -1;
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static int hf_bt_utp_data = -1;
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static int hf_bt_utp_pdu_size = -1;
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static int hf_bt_utp_continuation_to = -1;
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static expert_field ei_extension_len_invalid = EI_INIT;
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static gint ett_bt_utp = -1;
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static gint ett_bt_utp_extension = -1;
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static gboolean enable_version0 = FALSE;
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static guint max_window_size = V1_MAX_WINDOW_SIZE;
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/* XXX: Desegementation and OOO-reassembly are not supported yet */
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static gboolean utp_desegment = FALSE;
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/*static gboolean utp_reassemble_out_of_order = FALSE;*/
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static gboolean utp_analyze_seq = TRUE;
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static guint32 bt_utp_stream_count = 0;
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typedef struct _utp_multisegment_pdu {
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guint16 first_seq;
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guint16 last_seq;
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guint first_seq_start_offset;
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guint last_seq_end_offset;
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/*gint length;
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guint32 reassembly_id;*/
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guint32 first_frame;
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} utp_multisegment_pdu;
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typedef struct _utp_flow_t {
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#if 0
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/* XXX: Some other things to add in later. */
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gboolean base_seq_set;
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guint16 base_seq;
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guint32 fin;
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guint32 window;
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guint32 maxnextseq;
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#endif
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wmem_tree_t *multisegment_pdus;
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} utp_flow_t;
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typedef struct {
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guint32 stream;
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utp_flow_t flow[2];
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utp_flow_t *fwd;
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utp_flow_t *rev;
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#if 0
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/* XXX: Some other things to add in later. */
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nstime_t ts_first;
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nstime_t ts_prev;
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guint8 conversation_completeness;
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#endif
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} utp_stream_info_t;
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/* Per-packet header information. */
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typedef struct {
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guint8 type;
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gboolean v0;
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guint32 connection; /* The prelease "V0" version is 32 bit */
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guint32 stream;
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guint16 seq;
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guint16 ack;
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guint32 seglen; /* reported length remaining */
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gboolean have_seglen;
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proto_tree *tree; /* For the bittorrent subdissector to access */
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} utp_info_t;
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static utp_stream_info_t*
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get_utp_stream_info(packet_info *pinfo, utp_info_t *utp_info)
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{
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conversation_t* conv;
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utp_stream_info_t *stream_info;
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guint32 id_up, id_down;
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int direction;
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/* Handle connection ID wrapping correctly. (Mainline libutp source
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* does not appear to do this, probably fails to connect if the random
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* connection ID is GMAX_UINT16 and tries again.)
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*/
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if (utp_info->v0) {
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id_up = utp_info->connection+1;
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id_down = utp_info->connection-1;
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} else {
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id_up = (guint16)(utp_info->connection+1);
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id_down = (guint16)(utp_info->connection-1);
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}
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if (utp_info->type == ST_SYN) {
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/* SYN packets are special, they have the connection ID for the other
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* side, and allow us to know both.
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*/
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conv = find_conversation(pinfo->num, &pinfo->src, &pinfo->dst, CONVERSATION_BT_UTP,
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id_up, utp_info->connection, 0);
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if (!conv) {
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/* XXX: A SYN for between the same pair of hosts with a duplicate
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* connection ID in the same direction is almost surely a retransmission
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* (unless there's a client that doesn't actually generate random IDs.)
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* We could check to see if we've gotten a FIN or RST on that same
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* connection, and also could do like TCP and see if the initial sequence
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* number matches. (The latter still doesn't help if the client also
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* doesn't start with random sequence numbers.)
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*/
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conv = conversation_new(pinfo->num, &pinfo->src, &pinfo->dst, CONVERSATION_BT_UTP, id_up, utp_info->connection, 0);
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}
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} else {
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/* For non-SYN packets, we know our connection ID, but we don't know if
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* the other side has our ID+1 (src initiated the connection) or our ID-1
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* (dst initiated). We also don't want find_conversation() to accidentally
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* call conversation_set_port2() with the wrong ID. So first we see if
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* we have a wildcarded conversation around (if we've seen previous
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* non-SYN packets from our current direction but none in the other.)
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*/
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conv = find_conversation(pinfo->num, &pinfo->src, &pinfo->dst, CONVERSATION_BT_UTP, utp_info->connection, 0, NO_PORT_B);
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if (!conv) {
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/* Do we have a complete conversation originated by our src, or
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* possibly a wildcarded conversation originated in this direction
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* (but we saw a non-SYN for the non-initiating side first)? */
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conv = find_conversation(pinfo->num, &pinfo->src, &pinfo->dst, CONVERSATION_BT_UTP, utp_info->connection, id_up, 0);
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if (!conv) {
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/* As above, but dst initiated? */
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conv = find_conversation(pinfo->num, &pinfo->src, &pinfo->dst, CONVERSATION_BT_UTP, utp_info->connection, id_down, 0);
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if (!conv) {
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/* Didn't find it, so create a new wildcarded conversation. When we
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* get a packet for the other direction, find_conversation() above
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* will set port2 with the other connection ID.
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*/
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conv = conversation_new(pinfo->num, &pinfo->src, &pinfo->dst, CONVERSATION_BT_UTP, utp_info->connection, 0, NO_PORT2);
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}
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}
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}
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}
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stream_info = (utp_stream_info_t *)conversation_get_proto_data(conv, proto_bt_utp);
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if (!stream_info) {
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stream_info = wmem_new0(wmem_file_scope(), utp_stream_info_t);
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stream_info->stream = bt_utp_stream_count++;
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stream_info->flow[0].multisegment_pdus=wmem_tree_new(wmem_file_scope());
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stream_info->flow[1].multisegment_pdus=wmem_tree_new(wmem_file_scope());
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conversation_add_proto_data(conv, proto_bt_utp, stream_info);
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}
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/* check direction */
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direction=cmp_address(&pinfo->src, &pinfo->dst);
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/* if the addresses are equal, match the ports instead. Use
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* the UDP ports instead of the uTP connection IDs because
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* we don't know which ID is smaller if we don't have both. */
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if(direction==0) {
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direction= (pinfo->srcport > pinfo->destport) ? 1 : -1;
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}
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if(direction>=0) {
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stream_info->fwd=&(stream_info->flow[0]);
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stream_info->rev=&(stream_info->flow[1]);
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} else {
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stream_info->fwd=&(stream_info->flow[1]);
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stream_info->rev=&(stream_info->flow[0]);
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}
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return stream_info;
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}
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static void
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print_pdu_tracking_data(packet_info *pinfo, tvbuff_t *tvb, proto_tree *utp_tree, utp_multisegment_pdu *msp)
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{
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proto_item *item;
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col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[Continuation to #%u] ", msp->first_frame);
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item=proto_tree_add_uint(utp_tree, hf_bt_utp_continuation_to,
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tvb, 0, 0, msp->first_frame);
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proto_item_set_generated(item);
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}
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static int
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scan_for_next_pdu(tvbuff_t *tvb, proto_tree *utp_tree, packet_info *pinfo, wmem_tree_t *multisegment_pdus)
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{
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utp_multisegment_pdu *msp;
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utp_info_t *p_utp_info;
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guint16 seq, prev_seq;
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p_utp_info = (utp_info_t *)p_get_proto_data(pinfo->pool, pinfo, proto_bt_utp, pinfo->curr_layer_num);
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/* XXX: Wraparound is possible, as is cycling through all 16 bit
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* sequence numbers in a connection. We only do this path if
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* "seq analysis" is on; that ought to do something (relative
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* sequence numbers definitely, maybe extend the width?) to help,
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* but doesn't yet.
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*/
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seq = p_utp_info->seq;
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prev_seq = seq - 1;
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msp = (utp_multisegment_pdu *)wmem_tree_lookup32_le(multisegment_pdus, prev_seq);
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if (msp) {
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if(seq>msp->first_seq && seq<=msp->last_seq) {
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print_pdu_tracking_data(pinfo, tvb, utp_tree, msp);
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}
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/* If this segment is completely within a previous PDU
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* then we just skip this packet
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*/
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if(seq>msp->first_seq && seq<msp->last_seq) {
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return -1;
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}
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if(seq>msp->first_seq && seq==msp->last_seq) {
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if (!PINFO_FD_VISITED(pinfo) && p_utp_info->have_seglen) {
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/* Unlike TCP, the sequence numbers don't measure bytes, so
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* we can only really update the end of the MSP when the packets
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* are in order, and if we have the real segment length (so not
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* an unreassembled IP fragment).
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*/
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if (p_utp_info->seglen >= msp->last_seq_end_offset) {
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return msp->last_seq_end_offset;
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} else {
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msp->last_seq++;
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msp->last_seq_end_offset -= p_utp_info->seglen;
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return -1;
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}
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} else {
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/* We can still provide a hint to the offset start in some
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* cases even when we can't update the MSP.
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*/
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if (msp->last_seq_end_offset < tvb_reported_length(tvb)) {
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return msp->last_seq_end_offset;
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} else {
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return -1;
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}
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}
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}
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}
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return 0;
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}
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static utp_multisegment_pdu *
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pdu_store_sequencenumber_of_next_pdu(packet_info *pinfo, guint16 seq, int offset, guint32 bytes_until_next_pdu, wmem_tree_t *multisegment_pdus)
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{
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utp_multisegment_pdu *msp;
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msp = wmem_new(wmem_file_scope(), utp_multisegment_pdu);
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msp->first_seq = seq;
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msp->first_seq_start_offset = offset;
|
|
msp->last_seq = seq+1;
|
|
msp->last_seq_end_offset = bytes_until_next_pdu;
|
|
msp->first_frame = pinfo->num;
|
|
wmem_tree_insert32(multisegment_pdus, seq, (void *)msp);
|
|
|
|
return msp;
|
|
}
|
|
|
|
#if 0
|
|
static void
|
|
desegment_utp(tvbuff_t *tvb, packet_info *pinfo, int offset,
|
|
guint32 seq, guint32 nxtseq,
|
|
proto_tree *tree, proto_tree *utp_tree,
|
|
utp_stream_info_t *stream_info)
|
|
{
|
|
|
|
}
|
|
#endif
|
|
|
|
void
|
|
utp_dissect_pdus(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
|
|
gboolean proto_desegment, guint fixed_len,
|
|
guint (*get_pdu_len)(packet_info *, tvbuff_t *, int, void*),
|
|
dissector_t dissect_pdu, void* dissector_data)
|
|
{
|
|
volatile int offset = 0;
|
|
int offset_before;
|
|
guint captured_length_remaining;
|
|
volatile guint plen;
|
|
guint length;
|
|
tvbuff_t *next_tvb;
|
|
proto_item *item=NULL;
|
|
const char *saved_proto;
|
|
guint8 curr_layer_num;
|
|
wmem_list_frame_t *frame;
|
|
|
|
while (tvb_reported_length_remaining(tvb, offset) > 0) {
|
|
/*
|
|
* We use "tvb_ensure_captured_length_remaining()" to make
|
|
* sure there actually *is* data remaining. The protocol
|
|
* we're handling could conceivably consists of a sequence of
|
|
* fixed-length PDUs, and therefore the "get_pdu_len" routine
|
|
* might not actually fetch anything from the tvbuff, and thus
|
|
* might not cause an exception to be thrown if we've run past
|
|
* the end of the tvbuff.
|
|
*
|
|
* This means we're guaranteed that "captured_length_remaining" is positive.
|
|
*/
|
|
captured_length_remaining = tvb_ensure_captured_length_remaining(tvb, offset);
|
|
|
|
/*
|
|
* Can we do reassembly?
|
|
*/
|
|
if (proto_desegment && pinfo->can_desegment) {
|
|
/*
|
|
* Yes - is the fixed-length part of the PDU split across segment
|
|
* boundaries?
|
|
*/
|
|
if (captured_length_remaining < fixed_len) {
|
|
/*
|
|
* Yes. Tell the uTP dissector where the data for this message
|
|
* starts in the data it handed us and that we need "some more
|
|
* data." Don't tell it exactly how many bytes we need because
|
|
* if/when we ask for even more (after the header) that will
|
|
* break reassembly.
|
|
*/
|
|
pinfo->desegment_offset = offset;
|
|
pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
|
|
return;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Get the length of the PDU.
|
|
*/
|
|
plen = (*get_pdu_len)(pinfo, tvb, offset, dissector_data);
|
|
if (plen == 0) {
|
|
/*
|
|
* Support protocols which have a variable length which cannot
|
|
* always be determined within the given fixed_len.
|
|
*/
|
|
DISSECTOR_ASSERT(proto_desegment && pinfo->can_desegment);
|
|
pinfo->desegment_offset = offset;
|
|
pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
|
|
return;
|
|
}
|
|
if (plen < fixed_len) {
|
|
/*
|
|
* Either:
|
|
*
|
|
* 1) the length value extracted from the fixed-length portion
|
|
* doesn't include the fixed-length portion's length, and
|
|
* was so large that, when the fixed-length portion's
|
|
* length was added to it, the total length overflowed;
|
|
*
|
|
* 2) the length value extracted from the fixed-length portion
|
|
* includes the fixed-length portion's length, and the value
|
|
* was less than the fixed-length portion's length, i.e. it
|
|
* was bogus.
|
|
*
|
|
* Report this as a bounds error.
|
|
*/
|
|
show_reported_bounds_error(tvb, pinfo, tree);
|
|
return;
|
|
}
|
|
|
|
/* give a hint to uTP where the next PDU starts
|
|
* so that it can attempt to find it in case it starts
|
|
* somewhere in the middle of a segment.
|
|
*/
|
|
if(!pinfo->fd->visited && utp_analyze_seq) {
|
|
guint remaining_bytes;
|
|
remaining_bytes = tvb_reported_length_remaining(tvb, offset);
|
|
if(plen>remaining_bytes) {
|
|
pinfo->want_pdu_tracking=2;
|
|
pinfo->bytes_until_next_pdu=plen-remaining_bytes;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Can we do reassembly?
|
|
*/
|
|
if (proto_desegment && pinfo->can_desegment) {
|
|
/*
|
|
* Yes - is the PDU split across segment boundaries?
|
|
*/
|
|
if (captured_length_remaining < plen) {
|
|
/*
|
|
* Yes. Tell the TCP dissector where the data for this message
|
|
* starts in the data it handed us, and how many more bytes we
|
|
* need, and return.
|
|
*/
|
|
pinfo->desegment_offset = offset;
|
|
pinfo->desegment_len = plen - captured_length_remaining;
|
|
return;
|
|
}
|
|
}
|
|
|
|
curr_layer_num = pinfo->curr_layer_num-1;
|
|
frame = wmem_list_frame_prev(wmem_list_tail(pinfo->layers));
|
|
while (frame && (proto_bt_utp != (gint) GPOINTER_TO_UINT(wmem_list_frame_data(frame)))) {
|
|
frame = wmem_list_frame_prev(frame);
|
|
curr_layer_num--;
|
|
}
|
|
#if 0
|
|
if (captured_length_remaining >= plen || there are more packets)
|
|
{
|
|
#endif
|
|
/*
|
|
* Display the PDU length as a field
|
|
*/
|
|
item=proto_tree_add_uint(((utp_info_t *)p_get_proto_data(pinfo->pool, pinfo, proto_bt_utp, curr_layer_num))->tree,
|
|
hf_bt_utp_pdu_size,
|
|
tvb, offset, plen, plen);
|
|
proto_item_set_generated(item);
|
|
#if 0
|
|
} else {
|
|
item = proto_tree_add_expert_format((proto_tree *)p_get_proto_data(pinfo->pool, pinfo, proto_bt_utp, curr_layer_num),
|
|
tvb, offset, -1,
|
|
"PDU Size: %u cut short at %u",plen,captured_length_remaining);
|
|
proto_item_set_generated(item);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Construct a tvbuff containing the amount of the payload we have
|
|
* available. Make its reported length the amount of data in the PDU.
|
|
*/
|
|
length = captured_length_remaining;
|
|
if (length > plen) {
|
|
length = plen;
|
|
}
|
|
next_tvb = tvb_new_subset_length_caplen(tvb, offset, length, plen);
|
|
if (!(proto_desegment && pinfo->can_desegment)) {
|
|
/* If we can't do reassembly, give a hint that bounds errors
|
|
* are probably fragment errors. */
|
|
tvb_set_fragment(next_tvb);
|
|
}
|
|
|
|
/*
|
|
* Dissect the PDU.
|
|
*
|
|
* If it gets an error that means there's no point in
|
|
* dissecting any more PDUs, rethrow the exception in
|
|
* question.
|
|
*
|
|
* If it gets any other error, report it and continue, as that
|
|
* means that PDU got an error, but that doesn't mean we should
|
|
* stop dissecting PDUs within this frame or chunk of reassembled
|
|
* data.
|
|
*/
|
|
saved_proto = pinfo->current_proto;
|
|
TRY {
|
|
(*dissect_pdu)(next_tvb, pinfo, tree, dissector_data);
|
|
}
|
|
CATCH_NONFATAL_ERRORS {
|
|
show_exception(tvb, pinfo, tree, EXCEPT_CODE, GET_MESSAGE);
|
|
/*
|
|
* Restore the saved protocol as well; we do this after
|
|
* show_exception(), so that the "Malformed packet" indication
|
|
* shows the protocol for which dissection failed.
|
|
*/
|
|
pinfo->current_proto = saved_proto;
|
|
}
|
|
ENDTRY;
|
|
|
|
/*
|
|
* Step to the next PDU.
|
|
* Make sure we don't overflow.
|
|
*/
|
|
offset_before = offset;
|
|
offset += plen;
|
|
if (offset <= offset_before)
|
|
break;
|
|
}
|
|
}
|
|
|
|
static gint
|
|
get_utp_version(tvbuff_t *tvb) {
|
|
guint8 v0_flags;
|
|
guint8 v1_ver_type, ext, ext_len;
|
|
guint32 window;
|
|
guint len, offset = 0;
|
|
gint ver = -1;
|
|
|
|
/* Simple heuristics inspired by code from utp.cpp */
|
|
|
|
len = tvb_captured_length(tvb);
|
|
|
|
/* Version 1? */
|
|
if (len < V1_FIXED_HDR_SIZE) {
|
|
return -1;
|
|
}
|
|
|
|
v1_ver_type = tvb_get_guint8(tvb, 0);
|
|
ext = tvb_get_guint8(tvb, 1);
|
|
if (((v1_ver_type & 0x0f) == 1) && ((v1_ver_type>>4) < ST_NUM_STATES) &&
|
|
(ext < EXT_NUM_EXT)) {
|
|
window = tvb_get_guint32(tvb, 12, ENC_BIG_ENDIAN);
|
|
if (window > max_window_size) {
|
|
return -1;
|
|
}
|
|
ver = 1;
|
|
offset = V1_FIXED_HDR_SIZE;
|
|
} else if (enable_version0) {
|
|
/* Version 0? */
|
|
if (len < V0_FIXED_HDR_SIZE) {
|
|
return -1;
|
|
}
|
|
v0_flags = tvb_get_guint8(tvb, 18);
|
|
ext = tvb_get_guint8(tvb, 17);
|
|
if ((v0_flags < ST_NUM_STATES) && (ext < EXT_NUM_EXT)) {
|
|
ver = 0;
|
|
offset = V0_FIXED_HDR_SIZE;
|
|
}
|
|
}
|
|
|
|
if (ver < 0) {
|
|
return ver;
|
|
}
|
|
|
|
/* In V0 we could use the microseconds value as a heuristic, because
|
|
* it was tv_usec, but in the modern V1 we cannot, because it is
|
|
* computed by converting a time_t into a 64 bit quantity of microseconds
|
|
* and then taking the lower 32 bits, so all possible values are likely.
|
|
*/
|
|
/* If we have an extension, then check the next two bytes,
|
|
* the first of which is another extension type (likely NO_EXTENSION)
|
|
* and the second of which is a length, which must be at least 4.
|
|
*/
|
|
if (ext != EXT_NO_EXTENSION) {
|
|
if (len < offset + 2) {
|
|
return -1;
|
|
}
|
|
ext = tvb_get_guint8(tvb, offset);
|
|
ext_len = tvb_get_guint8(tvb, offset+1);
|
|
if (ext >= EXT_NUM_EXT || ext_len < 4) {
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
return ver;
|
|
}
|
|
|
|
static int
|
|
dissect_utp_header_v0(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int offset, guint8 *extension_type)
|
|
{
|
|
/* "Original" (V0) */
|
|
utp_info_t *p_utp_info = NULL;
|
|
utp_stream_info_t *stream_info = NULL;
|
|
|
|
proto_item *ti;
|
|
guint32 type, connection, win, seq, ack;
|
|
|
|
p_utp_info = wmem_new(pinfo->pool, utp_info_t);
|
|
p_utp_info->v0 = TRUE;
|
|
p_add_proto_data(pinfo->pool, pinfo, proto_bt_utp, pinfo->curr_layer_num, p_utp_info);
|
|
|
|
proto_tree_add_item_ret_uint(tree, hf_bt_utp_connection_id_v0, tvb, offset, 4, ENC_BIG_ENDIAN, &connection);
|
|
offset += 4;
|
|
proto_tree_add_item(tree, hf_bt_utp_timestamp_sec, tvb, offset, 4, ENC_BIG_ENDIAN);
|
|
offset += 4;
|
|
proto_tree_add_item(tree, hf_bt_utp_timestamp_us, tvb, offset, 4, ENC_BIG_ENDIAN);
|
|
offset += 4;
|
|
proto_tree_add_item(tree, hf_bt_utp_timestamp_diff_us, tvb, offset, 4, ENC_BIG_ENDIAN);
|
|
offset += 4;
|
|
proto_tree_add_item_ret_uint(tree, hf_bt_utp_wnd_size_v0, tvb, offset, 1, ENC_BIG_ENDIAN, &win);
|
|
offset += 1;
|
|
proto_tree_add_item(tree, hf_bt_utp_next_extension_type, tvb, offset, 1, ENC_BIG_ENDIAN);
|
|
*extension_type = tvb_get_guint8(tvb, offset);
|
|
offset += 1;
|
|
proto_tree_add_item_ret_uint(tree, hf_bt_utp_flags, tvb, offset, 1, ENC_BIG_ENDIAN, &type);
|
|
offset += 1;
|
|
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, "Connection ID:%d [%s]", connection, val_to_str(type, bt_utp_type_vals, "Unknown %d"));
|
|
p_utp_info->type = type;
|
|
p_utp_info->connection = connection;
|
|
|
|
proto_tree_add_item(tree, hf_bt_utp_seq_nr, tvb, offset, 2, ENC_BIG_ENDIAN);
|
|
offset += 2;
|
|
proto_tree_add_item(tree, hf_bt_utp_ack_nr, tvb, offset, 2, ENC_BIG_ENDIAN);
|
|
offset += 2;
|
|
|
|
proto_tree_add_item_ret_uint(tree, hf_bt_utp_seq_nr, tvb, offset, 2, ENC_BIG_ENDIAN, &seq);
|
|
col_append_str_uint(pinfo->cinfo, COL_INFO, "Seq", seq, " ");
|
|
p_utp_info->seq = seq;
|
|
offset += 2;
|
|
proto_tree_add_item_ret_uint(tree, hf_bt_utp_ack_nr, tvb, offset, 2, ENC_BIG_ENDIAN, &ack);
|
|
col_append_str_uint(pinfo->cinfo, COL_INFO, "Ack", ack, " ");
|
|
p_utp_info->ack = ack;
|
|
offset += 2;
|
|
col_append_str_uint(pinfo->cinfo, COL_INFO, "Win", win, " ");
|
|
|
|
stream_info = get_utp_stream_info(pinfo, p_utp_info);
|
|
ti = proto_tree_add_uint(tree, hf_bt_utp_stream, tvb, offset, 0, stream_info->stream);
|
|
p_utp_info->stream = stream_info->stream;
|
|
proto_item_set_generated(ti);
|
|
|
|
return offset;
|
|
}
|
|
|
|
static int
|
|
dissect_utp_header_v1(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int offset, guint8 *extension_type)
|
|
{
|
|
/* V1 */
|
|
utp_info_t *p_utp_info = NULL;
|
|
utp_stream_info_t *stream_info = NULL;
|
|
|
|
proto_item *ti;
|
|
|
|
guint32 type, connection, win, seq, ack;
|
|
|
|
p_utp_info = wmem_new(pinfo->pool, utp_info_t);
|
|
p_utp_info->v0 = FALSE;
|
|
p_add_proto_data(pinfo->pool, pinfo, proto_bt_utp, pinfo->curr_layer_num, p_utp_info);
|
|
|
|
proto_tree_add_item(tree, hf_bt_utp_ver, tvb, offset, 1, ENC_BIG_ENDIAN);
|
|
proto_tree_add_item_ret_uint(tree, hf_bt_utp_type, tvb, offset, 1, ENC_BIG_ENDIAN, &type);
|
|
offset += 1;
|
|
proto_tree_add_item(tree, hf_bt_utp_next_extension_type, tvb, offset, 1, ENC_BIG_ENDIAN);
|
|
*extension_type = tvb_get_guint8(tvb, offset);
|
|
offset += 1;
|
|
proto_tree_add_item_ret_uint(tree, hf_bt_utp_connection_id_v1, tvb, offset, 2, ENC_BIG_ENDIAN, &connection);
|
|
offset += 2;
|
|
|
|
col_append_fstr(pinfo->cinfo, COL_INFO, "Connection ID:%d [%s]", connection, val_to_str(type, bt_utp_type_vals, "Unknown %d"));
|
|
p_utp_info->type = type;
|
|
p_utp_info->connection = connection;
|
|
|
|
proto_tree_add_item(tree, hf_bt_utp_timestamp_us, tvb, offset, 4, ENC_BIG_ENDIAN);
|
|
offset += 4;
|
|
proto_tree_add_item(tree, hf_bt_utp_timestamp_diff_us, tvb, offset, 4, ENC_BIG_ENDIAN);
|
|
offset += 4;
|
|
proto_tree_add_item_ret_uint(tree, hf_bt_utp_wnd_size_v1, tvb, offset, 4, ENC_BIG_ENDIAN, &win);
|
|
offset += 4;
|
|
proto_tree_add_item_ret_uint(tree, hf_bt_utp_seq_nr, tvb, offset, 2, ENC_BIG_ENDIAN, &seq);
|
|
col_append_str_uint(pinfo->cinfo, COL_INFO, "Seq", seq, " ");
|
|
p_utp_info->seq = seq;
|
|
offset += 2;
|
|
proto_tree_add_item_ret_uint(tree, hf_bt_utp_ack_nr, tvb, offset, 2, ENC_BIG_ENDIAN, &ack);
|
|
col_append_str_uint(pinfo->cinfo, COL_INFO, "Ack", ack, " ");
|
|
p_utp_info->ack = ack;
|
|
offset += 2;
|
|
col_append_str_uint(pinfo->cinfo, COL_INFO, "Win", win, " ");
|
|
|
|
stream_info = get_utp_stream_info(pinfo, p_utp_info);
|
|
ti = proto_tree_add_uint(tree, hf_bt_utp_stream, tvb, offset, 0, stream_info->stream);
|
|
p_utp_info->stream = stream_info->stream;
|
|
proto_item_set_generated(ti);
|
|
|
|
/* XXX: Multisegment PDUs are the top priority to add, but a number of
|
|
* other features in the TCP dissector would be useful- relative sequence
|
|
* numbers, conversation completeness, maybe even tracking SACKs.
|
|
*/
|
|
return offset;
|
|
}
|
|
|
|
static int
|
|
dissect_utp_extension(tvbuff_t *tvb, packet_info _U_*pinfo, proto_tree *tree, int offset, guint8 *extension_type)
|
|
{
|
|
proto_item *ti;
|
|
proto_tree *ext_tree;
|
|
guint32 next_extension, extension_length;
|
|
/* display the extension tree */
|
|
|
|
while(*extension_type != EXT_NO_EXTENSION && offset < (int)tvb_reported_length(tvb))
|
|
{
|
|
ti = proto_tree_add_none_format(tree, hf_bt_utp_extension, tvb, offset, -1, "Extension: %s", val_to_str_const(*extension_type, bt_utp_extension_type_vals, "Unknown"));
|
|
ext_tree = proto_item_add_subtree(ti, ett_bt_utp_extension);
|
|
|
|
proto_tree_add_item_ret_uint(ext_tree, hf_bt_utp_next_extension_type, tvb, offset, 1, ENC_BIG_ENDIAN, &next_extension);
|
|
offset += 1;
|
|
|
|
proto_tree_add_item_ret_uint(ext_tree, hf_bt_utp_extension_len, tvb, offset, 1, ENC_BIG_ENDIAN, &extension_length);
|
|
proto_item_append_text(ti, ", Len=%d", extension_length);
|
|
offset += 1;
|
|
|
|
switch(*extension_type){
|
|
case EXT_SELECTIVE_ACKS: /* 1 */
|
|
{
|
|
proto_tree_add_item(ext_tree, hf_bt_utp_extension_bitmask, tvb, offset, extension_length, ENC_NA);
|
|
break;
|
|
}
|
|
case EXT_EXTENSION_BITS: /* 2 */
|
|
{
|
|
proto_tree_add_item(ext_tree, hf_bt_utp_extension_bitmask, tvb, offset, extension_length, ENC_NA);
|
|
break;
|
|
}
|
|
case EXT_CLOSE_REASON: /* 3 */
|
|
{
|
|
if (extension_length != 4) {
|
|
expert_add_info(pinfo, ti, &ei_extension_len_invalid);
|
|
}
|
|
proto_tree_add_item(ext_tree, hf_bt_utp_extension_close_reason, tvb, offset, 4, ENC_NA);
|
|
break;
|
|
}
|
|
default:
|
|
proto_tree_add_item(ext_tree, hf_bt_utp_extension_unknown, tvb, offset, extension_length, ENC_NA);
|
|
break;
|
|
}
|
|
offset += extension_length;
|
|
proto_item_set_len(ti, 1 + 1 + extension_length);
|
|
*extension_type = next_extension;
|
|
}
|
|
|
|
return offset;
|
|
}
|
|
|
|
static gboolean
|
|
decode_utp(tvbuff_t *tvb, int offset, packet_info *pinfo,
|
|
proto_tree *tree)
|
|
{
|
|
proto_tree *parent_tree;
|
|
tvbuff_t *next_tvb;
|
|
int save_desegment_offset;
|
|
guint32 save_desegment_len;
|
|
|
|
/* XXX: Check for retransmission? */
|
|
|
|
next_tvb = tvb_new_subset_remaining(tvb, offset);
|
|
|
|
save_desegment_offset = pinfo->desegment_offset;
|
|
save_desegment_len = pinfo->desegment_len;
|
|
|
|
/* The only possible payload is bittorrent */
|
|
|
|
parent_tree = proto_tree_get_parent_tree(tree);
|
|
if (call_dissector_with_data(bittorrent_handle, next_tvb, pinfo, parent_tree, NULL)) {
|
|
pinfo->want_pdu_tracking -= !!(pinfo->want_pdu_tracking);
|
|
return TRUE;
|
|
}
|
|
|
|
DISSECTOR_ASSERT(save_desegment_offset == pinfo->desegment_offset &&
|
|
save_desegment_len == pinfo->desegment_len);
|
|
|
|
call_data_dissector(tvb, pinfo, parent_tree);
|
|
pinfo->want_pdu_tracking -= !!(pinfo->want_pdu_tracking);
|
|
|
|
return FALSE;
|
|
}
|
|
|
|
static void
|
|
process_utp_payload(tvbuff_t *tvb, packet_info *pinfo,
|
|
proto_tree *tree, guint16 seq, gboolean is_utp_segment,
|
|
utp_stream_info_t *stream_info)
|
|
{
|
|
volatile int offset = 0;
|
|
pinfo->want_pdu_tracking = 0;
|
|
|
|
TRY {
|
|
if (is_utp_segment) {
|
|
/* See if an unaligned PDU */
|
|
if (stream_info && utp_analyze_seq && (!utp_desegment)) {
|
|
offset = scan_for_next_pdu(tvb, tree, pinfo,
|
|
stream_info->fwd->multisegment_pdus);
|
|
}
|
|
}
|
|
|
|
if ((offset != -1) && decode_utp(tvb, offset, pinfo, tree)) {
|
|
/*
|
|
* We succeeded in handing off to bittorent.
|
|
*
|
|
* Is this a segment (so we're not desegmenting for whatever
|
|
* reason)? Then at least do rudimentary PDU tracking.
|
|
*/
|
|
if(is_utp_segment) {
|
|
/* if !visited, check want_pdu_tracking and
|
|
store it in table */
|
|
if(stream_info && (!pinfo->fd->visited) &&
|
|
utp_analyze_seq && pinfo->want_pdu_tracking) {
|
|
pdu_store_sequencenumber_of_next_pdu(
|
|
pinfo,
|
|
seq,
|
|
offset,
|
|
pinfo->bytes_until_next_pdu,
|
|
stream_info->fwd->multisegment_pdus);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
CATCH_ALL {
|
|
/* We got an exception. Before dissection is aborted and execution
|
|
* is transferred back to (probably) the frame dissector, do PDU
|
|
* tracking if we need to because this is a segment.
|
|
*/
|
|
if (is_utp_segment) {
|
|
if(stream_info && (!pinfo->fd->visited) &&
|
|
utp_analyze_seq && pinfo->want_pdu_tracking) {
|
|
pdu_store_sequencenumber_of_next_pdu(
|
|
pinfo,
|
|
seq,
|
|
offset,
|
|
pinfo->bytes_until_next_pdu,
|
|
stream_info->fwd->multisegment_pdus);
|
|
}
|
|
}
|
|
RETHROW;
|
|
}
|
|
ENDTRY;
|
|
}
|
|
|
|
static guint
|
|
dissect_utp_payload(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
|
|
{
|
|
proto_item *ti;
|
|
|
|
utp_info_t *p_utp_info;
|
|
guint len_tvb;
|
|
gboolean save_fragmented;
|
|
|
|
p_utp_info = (utp_info_t *)p_get_proto_data(pinfo->pool, pinfo, proto_bt_utp, pinfo->curr_layer_num);
|
|
|
|
p_utp_info->tree = tree;
|
|
|
|
utp_stream_info_t *stream_info;
|
|
stream_info = get_utp_stream_info(pinfo, p_utp_info);
|
|
|
|
len_tvb = tvb_reported_length(tvb);
|
|
|
|
/* As with TCP, if we've been handed an IP fragment, we don't really
|
|
* know how big the segment is, and we don't really want to do anything
|
|
* if this is an error packet from ICMP or similar.
|
|
*
|
|
* XXX: We don't want to desegment if the UDP checksum is bad either.
|
|
* Need to add that to the per-packet info that UDP stores and access
|
|
* it.
|
|
*/
|
|
pinfo->can_desegment = 0;
|
|
if (!pinfo->fragmented && !pinfo->flags.in_error_pkt) {
|
|
p_utp_info->seglen = len_tvb;
|
|
p_utp_info->have_seglen = TRUE;
|
|
|
|
ti = proto_tree_add_uint(tree, hf_bt_utp_len, tvb, 0, 0, len_tvb);
|
|
proto_item_set_generated(ti);
|
|
col_append_str_uint(pinfo->cinfo, COL_INFO, "Len", len_tvb, " ");
|
|
|
|
if (utp_desegment && tvb_bytes_exist(tvb, 0, len_tvb)) {
|
|
/* If we actually have the bytes too then we can desegment. */
|
|
pinfo->can_desegment = 2;
|
|
}
|
|
} else {
|
|
p_utp_info->have_seglen = FALSE;
|
|
}
|
|
|
|
if(tvb_captured_length(tvb)) {
|
|
proto_tree_add_item(tree, hf_bt_utp_data, tvb, 0, len_tvb, ENC_NA);
|
|
if (pinfo->can_desegment) {
|
|
/* XXX: desegment_utp() is not implemented, but we can't get
|
|
* into this code path yet because utp_desegment is FALSE. */
|
|
} else {
|
|
save_fragmented = pinfo->fragmented;
|
|
pinfo->fragmented = TRUE;
|
|
process_utp_payload(tvb, pinfo, tree, p_utp_info->seq, TRUE, stream_info);
|
|
pinfo->fragmented = save_fragmented;
|
|
}
|
|
}
|
|
|
|
return len_tvb;
|
|
}
|
|
|
|
static int
|
|
dissect_bt_utp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
|
|
{
|
|
gint version;
|
|
version = get_utp_version(tvb);
|
|
|
|
/* try dissecting */
|
|
if (version >= 0)
|
|
{
|
|
proto_tree *sub_tree = NULL;
|
|
proto_item *ti;
|
|
gint offset = 0;
|
|
guint8 extension_type;
|
|
|
|
/* set the protocol column */
|
|
col_set_str(pinfo->cinfo, COL_PROTOCOL, "BT-uTP");
|
|
col_clear(pinfo->cinfo, COL_INFO);
|
|
|
|
/* Determine header version */
|
|
|
|
if (version == 0) {
|
|
ti = proto_tree_add_protocol_format(tree, proto_bt_utp, tvb, 0, -1,
|
|
"uTorrent Transport Protocol V0");
|
|
sub_tree = proto_item_add_subtree(ti, ett_bt_utp);
|
|
offset = dissect_utp_header_v0(tvb, pinfo, sub_tree, offset, &extension_type);
|
|
} else {
|
|
ti = proto_tree_add_item(tree, proto_bt_utp, tvb, 0, -1, ENC_NA);
|
|
sub_tree = proto_item_add_subtree(ti, ett_bt_utp);
|
|
offset = dissect_utp_header_v1(tvb, pinfo, sub_tree, offset, &extension_type);
|
|
}
|
|
|
|
offset = dissect_utp_extension(tvb, pinfo, sub_tree, offset, &extension_type);
|
|
|
|
offset += dissect_utp_payload(tvb_new_subset_remaining(tvb, offset), pinfo, sub_tree);
|
|
|
|
return offset;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static gboolean
|
|
dissect_bt_utp_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
|
|
{
|
|
gint version;
|
|
version = get_utp_version(tvb);
|
|
|
|
if (version >= 0)
|
|
{
|
|
conversation_t *conversation;
|
|
|
|
conversation = find_or_create_conversation(pinfo);
|
|
conversation_set_dissector_from_frame_number(conversation, pinfo->num, bt_utp_handle);
|
|
|
|
dissect_bt_utp(tvb, pinfo, tree, data);
|
|
return TRUE;
|
|
}
|
|
|
|
return FALSE;
|
|
}
|
|
|
|
static void
|
|
utp_init(void)
|
|
{
|
|
bt_utp_stream_count = 0;
|
|
}
|
|
|
|
void
|
|
proto_register_bt_utp(void)
|
|
{
|
|
static hf_register_info hf[] = {
|
|
{ &hf_bt_utp_ver,
|
|
{ "Version", "bt-utp.ver",
|
|
FT_UINT8, BASE_DEC, NULL, 0x0F,
|
|
NULL, HFILL }
|
|
},
|
|
{ &hf_bt_utp_flags,
|
|
{ "Flags", "bt-utp.flags",
|
|
FT_UINT8, BASE_DEC, VALS(bt_utp_type_vals), 0x0,
|
|
NULL, HFILL }
|
|
},
|
|
{ &hf_bt_utp_type,
|
|
{ "Type", "bt-utp.type",
|
|
FT_UINT8, BASE_DEC, VALS(bt_utp_type_vals), 0xF0,
|
|
NULL, HFILL }
|
|
},
|
|
{ &hf_bt_utp_extension,
|
|
{ "Extension", "bt-utp.extension",
|
|
FT_NONE, BASE_NONE, NULL, 0x0,
|
|
NULL, HFILL }
|
|
},
|
|
{ &hf_bt_utp_next_extension_type,
|
|
{ "Next Extension Type", "bt-utp.next_extension_type",
|
|
FT_UINT8, BASE_DEC, VALS(bt_utp_extension_type_vals), 0x0,
|
|
NULL, HFILL }
|
|
},
|
|
{ &hf_bt_utp_extension_len,
|
|
{ "Extension Length", "bt-utp.extension_len",
|
|
FT_UINT8, BASE_DEC|BASE_UNIT_STRING, &units_byte_bytes, 0x0,
|
|
NULL, HFILL }
|
|
},
|
|
{ &hf_bt_utp_extension_bitmask,
|
|
{ "Extension Bitmask", "bt-utp.extension_bitmask",
|
|
FT_BYTES, BASE_NONE, NULL, 0x0,
|
|
NULL, HFILL }
|
|
},
|
|
{ &hf_bt_utp_extension_close_reason,
|
|
{ "Close Reason", "bt-utp.extension_close_reason",
|
|
FT_UINT32, BASE_DEC, VALS(bt_utp_close_reason_vals), 0x0,
|
|
NULL, HFILL }
|
|
},
|
|
{ &hf_bt_utp_extension_unknown,
|
|
{ "Extension Unknown", "bt-utp.extension_unknown",
|
|
FT_BYTES, BASE_NONE, NULL, 0x0,
|
|
NULL, HFILL }
|
|
},
|
|
{ &hf_bt_utp_connection_id_v0,
|
|
{ "Connection ID", "bt-utp.connection_id",
|
|
FT_UINT32, BASE_DEC, NULL, 0x0,
|
|
NULL, HFILL }
|
|
},
|
|
{ &hf_bt_utp_connection_id_v1,
|
|
{ "Connection ID", "bt-utp.connection_id",
|
|
FT_UINT16, BASE_DEC, NULL, 0x0,
|
|
NULL, HFILL }
|
|
},
|
|
{ &hf_bt_utp_stream,
|
|
{ "Stream index", "bt-utp.stream",
|
|
FT_UINT32, BASE_DEC, NULL, 0x0,
|
|
NULL, HFILL }
|
|
},
|
|
{ &hf_bt_utp_timestamp_sec,
|
|
{ "Timestamp seconds", "bt-utp.timestamp_sec",
|
|
FT_UINT32, BASE_DEC, NULL, 0x0,
|
|
NULL, HFILL }
|
|
},
|
|
{ &hf_bt_utp_timestamp_us,
|
|
{ "Timestamp Microseconds", "bt-utp.timestamp_us",
|
|
FT_UINT32, BASE_DEC, NULL, 0x0,
|
|
NULL, HFILL }
|
|
},
|
|
{ &hf_bt_utp_timestamp_diff_us,
|
|
{ "Timestamp Difference Microseconds", "bt-utp.timestamp_diff_us",
|
|
FT_UINT32, BASE_DEC, NULL, 0x0,
|
|
NULL, HFILL }
|
|
},
|
|
{ &hf_bt_utp_wnd_size_v0,
|
|
{ "Window Size", "bt-utp.wnd_size",
|
|
FT_UINT8, BASE_DEC, NULL, 0x0,
|
|
"V0 receive window size, in multiples of 350 bytes", HFILL }
|
|
},
|
|
{ &hf_bt_utp_wnd_size_v1,
|
|
{ "Window Size", "bt-utp.wnd_size",
|
|
FT_UINT32, BASE_DEC|BASE_UNIT_STRING, &units_byte_bytes, 0x0,
|
|
NULL, HFILL }
|
|
},
|
|
{ &hf_bt_utp_seq_nr,
|
|
{ "Sequence number", "bt-utp.seq_nr",
|
|
FT_UINT16, BASE_DEC, NULL, 0x0,
|
|
NULL, HFILL }
|
|
},
|
|
{ &hf_bt_utp_ack_nr,
|
|
{ "ACK number", "bt-utp.ack_nr",
|
|
FT_UINT16, BASE_DEC, NULL, 0x0,
|
|
NULL, HFILL }
|
|
},
|
|
{ &hf_bt_utp_len,
|
|
{ "uTP Segment Len", "bt-utp.len",
|
|
FT_UINT32, BASE_DEC, NULL, 0x0,
|
|
NULL, HFILL }
|
|
},
|
|
{ &hf_bt_utp_data,
|
|
{ "Data", "bt-utp.data",
|
|
FT_BYTES, BASE_NONE, NULL, 0x0,
|
|
NULL, HFILL }
|
|
},
|
|
{ &hf_bt_utp_pdu_size,
|
|
{ "PDU Size", "bt-utp.pdu.size",
|
|
FT_UINT32, BASE_DEC, NULL, 0x0,
|
|
"The size of this PDU", HFILL }
|
|
},
|
|
{ &hf_bt_utp_continuation_to,
|
|
{ "This is a continuation to the PDU in frame",
|
|
"bt-utp.continuation_to", FT_FRAMENUM, BASE_NONE,
|
|
NULL, 0x0, "This is a continuation to the PDU in frame #", HFILL }
|
|
},
|
|
};
|
|
|
|
static ei_register_info ei[] = {
|
|
{ &ei_extension_len_invalid,
|
|
{ "bt-utp.extension_len.invalid", PI_PROTOCOL, PI_WARN,
|
|
"The extension is an unexpected length", EXPFILL }
|
|
},
|
|
};
|
|
|
|
/* Setup protocol subtree array */
|
|
static gint *ett[] = { &ett_bt_utp, &ett_bt_utp_extension };
|
|
|
|
module_t *bt_utp_module;
|
|
expert_module_t *expert_bt_utp;
|
|
|
|
/* Register protocol */
|
|
proto_bt_utp = proto_register_protocol ("uTorrent Transport Protocol", "BT-uTP", "bt-utp");
|
|
|
|
bt_utp_module = prefs_register_protocol(proto_bt_utp, NULL);
|
|
prefs_register_obsolete_preference(bt_utp_module, "enable");
|
|
prefs_register_bool_preference(bt_utp_module,
|
|
"analyze_sequence_numbers",
|
|
"Analyze uTP sequence numbers",
|
|
"Make the uTP dissector analyze uTP sequence numbers. Currently this "
|
|
"just means that it tries to find the correct start offset of a PDU "
|
|
"if it detected that previous in-order packets spanned multiple "
|
|
"frames.",
|
|
&utp_analyze_seq);
|
|
prefs_register_bool_preference(bt_utp_module,
|
|
"enable_version0",
|
|
"Dissect prerelease (version 0) packets",
|
|
"Whether the dissector should attempt to dissect packets with the "
|
|
"obsolete format (version 0) that predates BEP 29 (22-Jun-2009)",
|
|
&enable_version0);
|
|
prefs_register_uint_preference(bt_utp_module,
|
|
"max_window_size",
|
|
"Maximum window size (in hex)",
|
|
"Maximum receive window size allowed by the dissector. Early clients "
|
|
"(and a few modern ones) set this value to 0x380000 (the default), "
|
|
"later ones use smaller values like 0x100000 and 0x40000. A higher "
|
|
"value can detect nonstandard packets, but at the cost of false "
|
|
"positives.",
|
|
16, &max_window_size);
|
|
|
|
proto_register_field_array(proto_bt_utp, hf, array_length(hf));
|
|
proto_register_subtree_array(ett, array_length(ett));
|
|
|
|
expert_bt_utp = expert_register_protocol(proto_bt_utp);
|
|
expert_register_field_array(expert_bt_utp, ei, array_length(ei));
|
|
|
|
register_init_routine(utp_init);
|
|
}
|
|
|
|
void
|
|
proto_reg_handoff_bt_utp(void)
|
|
{
|
|
/* disabled by default since heuristic is weak */
|
|
/* XXX: The heuristic is stronger now, but might still get false positives
|
|
* on packets with lots of zero bytes. Needs more testing before enabling
|
|
* by default.
|
|
*/
|
|
heur_dissector_add("udp", dissect_bt_utp_heur, "BitTorrent UTP over UDP", "bt_utp_udp", proto_bt_utp, HEURISTIC_DISABLE);
|
|
|
|
bt_utp_handle = create_dissector_handle(dissect_bt_utp, proto_bt_utp);
|
|
dissector_add_for_decode_as_with_preference("udp.port", bt_utp_handle);
|
|
|
|
bittorrent_handle = find_dissector_add_dependency("bittorrent.utp", proto_bt_utp);
|
|
}
|
|
|
|
/*
|
|
* Editor modelines
|
|
*
|
|
* Local Variables:
|
|
* c-basic-offset: 2
|
|
* tab-width: 8
|
|
* indent-tabs-mode: nil
|
|
* End:
|
|
*
|
|
* ex: set shiftwidth=2 tabstop=8 expandtab:
|
|
* :indentSize=2:tabSize=8:noTabs=true:
|
|
*/
|
|
|