489 lines
16 KiB
C
489 lines
16 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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*
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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/prefs.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_SELECTION_ACKS = 1,
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EXT_EXTENSION_BITS = 2,
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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_SELECTION_ACKS, "Selective ACKs" },
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{ EXT_EXTENSION_BITS, "Extension bits" },
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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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static dissector_handle_t bt_utp_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_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_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_data = -1;
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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 gint
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get_utp_version(tvbuff_t *tvb) {
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guint8 v0_flags, v0_ext;
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guint8 v1_ver_type, v1_ext;
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guint len;
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/* Simple heuristics inspired by code from utp.cpp */
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len = tvb_captured_length(tvb);
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/* Version 1? */
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if (len < V1_FIXED_HDR_SIZE) {
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return -1;
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}
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v1_ver_type = tvb_get_guint8(tvb, 0);
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v1_ext = tvb_get_guint8(tvb, 1);
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if (((v1_ver_type & 0x0f) == 1) && ((v1_ver_type>>4) < ST_NUM_STATES) &&
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(v1_ext < EXT_NUM_EXT)) {
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return 1;
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}
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/* Version 0? */
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if (len < V0_FIXED_HDR_SIZE) {
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return -1;
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}
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v0_flags = tvb_get_guint8(tvb, 18);
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v0_ext = tvb_get_guint8(tvb, 17);
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if ((v0_flags < ST_NUM_STATES) || (v0_ext < EXT_NUM_EXT)) {
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return 0;
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}
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return -1;
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}
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static int
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dissect_utp_header_v0(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int offset, guint8 *extension_type)
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{
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/* "Original" (V0) */
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proto_tree_add_item(tree, hf_bt_utp_connection_id_v0, tvb, offset, 4, ENC_BIG_ENDIAN);
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offset += 4;
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proto_tree_add_item(tree, hf_bt_utp_timestamp_sec, tvb, offset, 4, ENC_BIG_ENDIAN);
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offset += 4;
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proto_tree_add_item(tree, hf_bt_utp_timestamp_us, tvb, offset, 4, ENC_BIG_ENDIAN);
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offset += 4;
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proto_tree_add_item(tree, hf_bt_utp_timestamp_diff_us, tvb, offset, 4, ENC_BIG_ENDIAN);
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offset += 4;
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proto_tree_add_item(tree, hf_bt_utp_wnd_size_v0, tvb, offset, 1, ENC_BIG_ENDIAN);
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offset += 1;
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proto_tree_add_item(tree, hf_bt_utp_next_extension_type, tvb, offset, 1, ENC_BIG_ENDIAN);
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*extension_type = tvb_get_guint8(tvb, offset);
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offset += 1;
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proto_tree_add_item(tree, hf_bt_utp_flags, tvb, offset, 1, ENC_BIG_ENDIAN);
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col_append_fstr(pinfo->cinfo, COL_INFO, " Type: %s", val_to_str(tvb_get_guint8(tvb, offset), bt_utp_type_vals, "Unknown %d"));
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offset += 1;
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proto_tree_add_item(tree, hf_bt_utp_seq_nr, tvb, offset, 2, ENC_BIG_ENDIAN);
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offset += 2;
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proto_tree_add_item(tree, hf_bt_utp_ack_nr, tvb, offset, 2, ENC_BIG_ENDIAN);
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offset += 2;
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return offset;
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}
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static int
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dissect_utp_header_v1(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int offset, guint8 *extension_type)
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{
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/* V1 */
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proto_tree_add_item(tree, hf_bt_utp_ver, tvb, offset, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(tree, hf_bt_utp_type, tvb, offset, 1, ENC_BIG_ENDIAN);
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col_append_fstr(pinfo->cinfo, COL_INFO, " Type: %s", val_to_str((tvb_get_guint8(tvb, offset) >> 4), bt_utp_type_vals, "Unknown %d"));
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offset += 1;
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proto_tree_add_item(tree, hf_bt_utp_next_extension_type, tvb, offset, 1, ENC_BIG_ENDIAN);
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*extension_type = tvb_get_guint8(tvb, offset);
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offset += 1;
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proto_tree_add_item(tree, hf_bt_utp_connection_id_v1, tvb, offset, 2, ENC_BIG_ENDIAN);
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offset += 2;
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proto_tree_add_item(tree, hf_bt_utp_timestamp_us, tvb, offset, 4, ENC_BIG_ENDIAN);
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offset += 4;
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proto_tree_add_item(tree, hf_bt_utp_timestamp_diff_us, tvb, offset, 4, ENC_BIG_ENDIAN);
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offset += 4;
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proto_tree_add_item(tree, hf_bt_utp_wnd_size_v1, tvb, offset, 4, ENC_BIG_ENDIAN);
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offset += 4;
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proto_tree_add_item(tree, hf_bt_utp_seq_nr, tvb, offset, 2, ENC_BIG_ENDIAN);
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offset += 2;
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proto_tree_add_item(tree, hf_bt_utp_ack_nr, tvb, offset, 2, ENC_BIG_ENDIAN);
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offset += 2;
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return offset;
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}
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static int
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dissect_utp_extension(tvbuff_t *tvb, packet_info _U_*pinfo, proto_tree *tree, int offset, guint8 *extension_type)
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{
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proto_item *ti;
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proto_tree *ext_tree;
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guint8 extension_length;
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/* display the extension tree */
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while(*extension_type != EXT_NO_EXTENSION && offset < (int)tvb_reported_length(tvb))
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{
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switch(*extension_type){
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case EXT_SELECTION_ACKS: /* 1 */
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{
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ti = proto_tree_add_item(tree, hf_bt_utp_extension, tvb, offset, -1, ENC_NA);
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ext_tree = proto_item_add_subtree(ti, ett_bt_utp_extension);
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proto_tree_add_item(ext_tree, hf_bt_utp_next_extension_type, tvb, offset, 1, ENC_BIG_ENDIAN);
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*extension_type = tvb_get_guint8(tvb, offset);
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offset += 1;
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proto_tree_add_item(ext_tree, hf_bt_utp_extension_len, tvb, offset, 1, ENC_BIG_ENDIAN);
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extension_length = tvb_get_guint8(tvb, offset);
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proto_item_append_text(ti, " Selection ACKs, Len=%d", extension_length);
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offset += 1;
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proto_tree_add_item(ext_tree, hf_bt_utp_extension_bitmask, tvb, offset, extension_length, ENC_NA);
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offset += extension_length;
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proto_item_set_len(ti, 1 + 1 + extension_length);
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break;
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}
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case EXT_EXTENSION_BITS: /* 2 */
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{
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ti = proto_tree_add_item(tree, hf_bt_utp_extension, tvb, offset, -1, ENC_NA);
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ext_tree = proto_item_add_subtree(ti, ett_bt_utp_extension);
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proto_tree_add_item(ext_tree, hf_bt_utp_next_extension_type, tvb, offset, 1, ENC_BIG_ENDIAN);
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*extension_type = tvb_get_guint8(tvb, offset);
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offset += 1;
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proto_tree_add_item(ext_tree, hf_bt_utp_extension_len, tvb, offset, 1, ENC_BIG_ENDIAN);
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extension_length = tvb_get_guint8(tvb, offset);
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proto_item_append_text(ti, " Extension Bits, Len=%d", extension_length);
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offset += 1;
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proto_tree_add_item(ext_tree, hf_bt_utp_extension_bitmask, tvb, offset, extension_length, ENC_NA);
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offset += extension_length;
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proto_item_set_len(ti, 1 + 1 + extension_length);
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break;
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}
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default:
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ti = proto_tree_add_item(tree, hf_bt_utp_extension, tvb, offset, -1, ENC_NA);
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ext_tree = proto_item_add_subtree(ti, ett_bt_utp_extension);
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proto_tree_add_item(ext_tree, hf_bt_utp_next_extension_type, tvb, offset, 1, ENC_BIG_ENDIAN);
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*extension_type = tvb_get_guint8(tvb, offset);
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offset += 1;
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proto_tree_add_item(ext_tree, hf_bt_utp_extension_len, tvb, offset, 1, ENC_BIG_ENDIAN);
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extension_length = tvb_get_guint8(tvb, offset);
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proto_item_append_text(ti, " Unknown, Len=%d", extension_length);
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offset += 1;
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proto_tree_add_item(ext_tree, hf_bt_utp_extension_unknown, tvb, offset, extension_length, ENC_NA);
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offset += extension_length;
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proto_item_set_len(ti, 1 + 1 + extension_length);
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break;
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}
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}
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return offset;
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}
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static int
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dissect_bt_utp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
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{
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gint version;
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version = get_utp_version(tvb);
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/* try dissecting */
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if (version >= 0)
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{
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conversation_t *conversation;
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guint len_tvb;
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proto_tree *sub_tree = NULL;
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proto_item *ti;
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gint offset = 0;
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guint8 extension_type;
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conversation = find_or_create_conversation(pinfo);
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conversation_set_dissector(conversation, bt_utp_handle);
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/* set the protocol column */
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "BT-uTP");
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/* set the info column */
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col_set_str( pinfo->cinfo, COL_INFO, "uTorrent Transport Protocol" );
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len_tvb = tvb_reported_length(tvb);
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ti = proto_tree_add_protocol_format(tree, proto_bt_utp, tvb, 0, -1,
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"uTorrent Transport Protocol V%d (%d bytes)",
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version, len_tvb);
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sub_tree = proto_item_add_subtree(ti, ett_bt_utp);
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/* Determine header version */
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if (version == 0) {
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offset = dissect_utp_header_v0(tvb, pinfo, sub_tree, offset, &extension_type);
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} else {
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offset = dissect_utp_header_v1(tvb, pinfo, sub_tree, offset, &extension_type);
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}
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offset = dissect_utp_extension(tvb, pinfo, sub_tree, offset, &extension_type);
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len_tvb = tvb_captured_length_remaining(tvb, offset);
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if(len_tvb > 0)
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proto_tree_add_item(sub_tree, hf_bt_utp_data, tvb, offset, len_tvb, ENC_NA);
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return offset+len_tvb;
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}
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return 0;
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}
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void
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proto_register_bt_utp(void)
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{
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static hf_register_info hf[] = {
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{ &hf_bt_utp_ver,
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{ "Version", "bt-utp.ver",
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FT_UINT8, BASE_DEC, NULL, 0x0F,
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NULL, HFILL }
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},
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{ &hf_bt_utp_flags,
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{ "Flags", "bt-utp.flags",
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FT_UINT8, BASE_DEC, VALS(bt_utp_type_vals), 0x0,
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NULL, HFILL }
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},
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{ &hf_bt_utp_type,
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{ "Type", "bt-utp.type",
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FT_UINT8, BASE_DEC, VALS(bt_utp_type_vals), 0xF0,
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NULL, HFILL }
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},
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{ &hf_bt_utp_extension,
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{ "Extension", "bt-utp.extension",
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FT_NONE, BASE_NONE, NULL, 0x0,
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NULL, HFILL }
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},
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{ &hf_bt_utp_next_extension_type,
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{ "Next Extension Type", "bt-utp.next_extension_type",
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FT_UINT8, BASE_DEC, VALS(bt_utp_extension_type_vals), 0x0,
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NULL, HFILL }
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},
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{ &hf_bt_utp_extension_len,
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{ "Extension Length", "bt-utp.extension_len",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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NULL, HFILL }
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},
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{ &hf_bt_utp_extension_bitmask,
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{ "Extension Bitmask", "bt-utp.extension_bitmask",
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FT_BYTES, BASE_NONE, NULL, 0x0,
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NULL, HFILL }
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},
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{ &hf_bt_utp_extension_unknown,
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{ "Extension Unknown", "bt-utp.extension_unknown",
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FT_BYTES, BASE_NONE, NULL, 0x0,
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NULL, HFILL }
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},
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{ &hf_bt_utp_connection_id_v0,
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{ "Connection ID", "bt-utp.connection_id",
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FT_UINT32, BASE_DEC, NULL, 0x0,
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NULL, HFILL }
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},
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{ &hf_bt_utp_connection_id_v1,
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{ "Connection ID", "bt-utp.connection_id",
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FT_UINT16, BASE_DEC, NULL, 0x0,
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NULL, HFILL }
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},
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{ &hf_bt_utp_timestamp_sec,
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{ "Timestamp seconds", "bt-utp.timestamp_sec",
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FT_UINT32, BASE_DEC, NULL, 0x0,
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NULL, HFILL }
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},
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{ &hf_bt_utp_timestamp_us,
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{ "Timestamp Microseconds", "bt-utp.timestamp_us",
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FT_UINT32, BASE_DEC, NULL, 0x0,
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NULL, HFILL }
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},
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{ &hf_bt_utp_timestamp_diff_us,
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{ "Timestamp Difference Microseconds", "bt-utp.timestamp_diff_us",
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FT_UINT32, BASE_DEC, NULL, 0x0,
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NULL, HFILL }
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},
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{ &hf_bt_utp_wnd_size_v0,
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{ "Windows Size", "bt-utp.wnd_size",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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NULL, HFILL }
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},
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{ &hf_bt_utp_wnd_size_v1,
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{ "Windows Size", "bt-utp.wnd_size",
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FT_UINT32, BASE_DEC, NULL, 0x0,
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NULL, HFILL }
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},
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{ &hf_bt_utp_seq_nr,
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|
{ "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_data,
|
|
{ "Data", "bt-utp.data",
|
|
FT_BYTES, BASE_NONE, NULL, 0x0,
|
|
NULL, HFILL }
|
|
},
|
|
};
|
|
|
|
/* Setup protocol subtree array */
|
|
static gint *ett[] = { &ett_bt_utp, &ett_bt_utp_extension };
|
|
|
|
module_t *bt_utp_module;
|
|
|
|
/* 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");
|
|
|
|
proto_register_field_array(proto_bt_utp, hf, array_length(hf));
|
|
proto_register_subtree_array(ett, array_length(ett));
|
|
}
|
|
|
|
void
|
|
proto_reg_handoff_bt_utp(void)
|
|
{
|
|
/* disabled by default since heuristic is weak */
|
|
heur_dissector_add("udp", dissect_bt_utp, "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);
|
|
}
|
|
|
|
/*
|
|
* 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:
|
|
*/
|
|
|