forked from osmocom/wireshark
![Dario Lombardo](/assets/img/avatar_default.png)
Change-Id: I92c94448e6641716d03158a5f332c8b53709423a Reviewed-on: https://code.wireshark.org/review/25756 Petri-Dish: Dario Lombardo <lomato@gmail.com> Reviewed-by: Anders Broman <a.broman58@gmail.com>
453 lines
12 KiB
C
453 lines
12 KiB
C
/* packet-skype.c
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* Routines for the disassembly of Skype
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*
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* Copyright 2009 Joerg Mayer (see AUTHORS file)
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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 1998 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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/*
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* Documentation that formed the basis of the packet decoding:
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* https://github.com/matthiasbock/OpenSkype/wiki/Skype's-UDP-Format
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* For additional information see: https://wiki.wireshark.org/Skype
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*
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* TODO:
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* - Authentication
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* - TCP
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* - Conversation stuff (to obtain external IPs for decryption)
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* - Decryption (with given keys)
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* - Test CRC check (requires working decryption)
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* - Heuristics to reliably detect Skype traffic - most likely impossible
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* to implement in Wireshark (see http://en.wikipedia.org/wiki/Skype)
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* - Improve tests
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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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void proto_register_skype(void);
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void proto_reg_handoff_skype(void);
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/* Things we may want to remember for a whole conversation */
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typedef struct _skype_udp_conv_info_t {
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guint32 global_src_ip;
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guint32 global_dst_ip;
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} skype_udp_conv_info_t;
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/* protocol handles */
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static int proto_skype = -1;
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/* ett handles */
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static int ett_skype = -1;
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#define SKYPE_SOM_UNK_MASK 0xF0
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#define SKYPE_SOM_TYPE_MASK 0x0F
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/* hf elements */
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/* Start of Message */
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static int hf_skype_som_id = -1;
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static int hf_skype_som_unk = -1;
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static int hf_skype_som_type = -1;
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/* Message body */
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/* Unknown_0 */
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static int hf_skype_unknown_0_unk1 = -1;
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/* Payload */
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static int hf_skype_payload_iv = -1;
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static int hf_skype_payload_crc = -1;
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static int hf_skype_payload_enc_data = -1;
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/* Resend */
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static int hf_skype_ffr_num = -1;
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static int hf_skype_ffr_unk1 = -1;
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static int hf_skype_ffr_iv = -1;
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static int hf_skype_ffr_crc = -1;
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static int hf_skype_ffr_enc_data = -1;
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/* Nat info */
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static int hf_skype_natinfo_srcip = -1;
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static int hf_skype_natinfo_dstip = -1;
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/* Nat request */
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static int hf_skype_natrequest_srcip = -1;
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static int hf_skype_natrequest_dstip = -1;
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/* Audio */
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static int hf_skype_audio_unk1 = -1;
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/* Unknown_f */
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static int hf_skype_unknown_f_unk1 = -1;
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/* Unknown packet type */
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static int hf_skype_unknown_packet = -1;
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#define PROTO_SHORT_NAME "SKYPE"
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#define PROTO_LONG_NAME "SKYPE"
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typedef enum {
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SKYPE_TYPE_UNKNOWN_0 = 0,
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SKYPE_TYPE_PAYLOAD = 2,
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SKYPE_TYPE_FFR = 3,
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SKYPE_TYPE_NAT_INFO = 5,
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SKYPE_TYPE_NAT_REPEAT = 7,
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SKYPE_TYPE_AUDIO = 0xd,
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SKYPE_TYPE_UNKNOWN_F = 0xf
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} skype_type_t;
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static const value_string skype_type_vals[] = {
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{ SKYPE_TYPE_UNKNOWN_0, "Unknown_0" },
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{ SKYPE_TYPE_PAYLOAD, "Payload" },
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{ SKYPE_TYPE_FFR, "Fragment/Forward/Resend" },
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{ SKYPE_TYPE_NAT_INFO , "NAT info" },
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{ SKYPE_TYPE_NAT_REPEAT,"NAT repeat" },
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{ SKYPE_TYPE_AUDIO, "Audio" },
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{ SKYPE_TYPE_UNKNOWN_F, "Unknown_F" },
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{ 0, NULL }
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};
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static int
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dissect_skype_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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proto_item *ti;
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proto_tree *skype_tree = NULL;
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guint32 offset = 0;
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guint32 packet_length;
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guint8 packet_type;
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/* XXX: Just until we know how to decode skype over tcp */
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packet_type = 255;
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packet_length = tvb_captured_length(tvb);
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col_set_str(pinfo->cinfo, COL_PROTOCOL, PROTO_SHORT_NAME);
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col_add_str(pinfo->cinfo, COL_INFO, val_to_str(packet_type,
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skype_type_vals, "Type 0x%1x"));
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if (tree) {
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/* Start of message dissection */
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ti = proto_tree_add_item(tree, proto_skype, tvb, offset, -1,
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ENC_NA);
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skype_tree = proto_item_add_subtree(ti, ett_skype);
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/* Body dissection */
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switch (packet_type) {
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default:
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proto_tree_add_item(skype_tree, hf_skype_unknown_packet, tvb, offset, -1,
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ENC_NA);
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offset = packet_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_skype_udp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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proto_item *ti;
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proto_tree *skype_tree = NULL;
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guint32 offset = 0;
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guint32 packet_length;
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guint8 packet_type, packet_unk;
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conversation_t *conversation = NULL;
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skype_udp_conv_info_t *skype_udp_info;
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/* look up the conversation */
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conversation = find_or_create_conversation(pinfo);
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/* if conversation found get the data pointer that you stored */
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skype_udp_info = (skype_udp_conv_info_t *)conversation_get_proto_data(conversation, proto_skype);
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if (!skype_udp_info) {
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/* new conversation create local data structure */
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skype_udp_info = wmem_new(wmem_file_scope(), skype_udp_conv_info_t);
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skype_udp_info->global_src_ip = 0;
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skype_udp_info->global_dst_ip = 0;
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conversation_add_proto_data(conversation, proto_skype,
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skype_udp_info);
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}
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/* at this point the conversation data is ready */
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packet_type = tvb_get_guint8(tvb, 2) & SKYPE_SOM_TYPE_MASK;
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packet_unk = (tvb_get_guint8(tvb, 2) & SKYPE_SOM_UNK_MASK) >> 4;
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packet_length = tvb_captured_length(tvb);
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col_set_str(pinfo->cinfo, COL_PROTOCOL, PROTO_SHORT_NAME);
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col_add_str(pinfo->cinfo, COL_INFO, val_to_str(packet_type,
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skype_type_vals, "Type 0x%1x"));
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if (packet_unk) {
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col_append_fstr(pinfo->cinfo, COL_INFO, " Unk: %1x", packet_unk);
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}
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if (tree) {
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/* Start of message dissection */
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ti = proto_tree_add_item(tree, proto_skype, tvb, offset, -1,
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ENC_NA);
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skype_tree = proto_item_add_subtree(ti, ett_skype);
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proto_tree_add_item(skype_tree, hf_skype_som_id, tvb, offset, 2,
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ENC_BIG_ENDIAN);
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offset += 2;
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proto_tree_add_item(skype_tree, hf_skype_som_unk, tvb, offset, 1,
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ENC_BIG_ENDIAN);
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proto_tree_add_item(skype_tree, hf_skype_som_type, tvb, offset, 1,
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ENC_BIG_ENDIAN);
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offset += 1;
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/* Body dissection */
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switch (packet_type) {
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case SKYPE_TYPE_UNKNOWN_0:
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proto_tree_add_item(skype_tree, hf_skype_unknown_0_unk1, tvb, offset, -1,
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ENC_NA);
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offset = packet_length;
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break;
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case SKYPE_TYPE_PAYLOAD:
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proto_tree_add_item(skype_tree, hf_skype_payload_iv, tvb, offset, 4,
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ENC_BIG_ENDIAN);
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offset += 4;
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proto_tree_add_item(skype_tree, hf_skype_payload_crc, tvb, offset, 4,
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ENC_BIG_ENDIAN);
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offset += 4;
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proto_tree_add_item(skype_tree, hf_skype_payload_enc_data, tvb, offset, -1,
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ENC_NA);
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offset = packet_length;
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break;
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case SKYPE_TYPE_FFR:
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proto_tree_add_item(skype_tree, hf_skype_ffr_num, tvb, offset, 1,
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ENC_BIG_ENDIAN);
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offset += 1;
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proto_tree_add_item(skype_tree, hf_skype_ffr_unk1, tvb, offset, 4,
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ENC_BIG_ENDIAN);
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offset += 4;
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proto_tree_add_item(skype_tree, hf_skype_ffr_iv, tvb, offset, 4,
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ENC_BIG_ENDIAN);
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offset += 4;
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proto_tree_add_item(skype_tree, hf_skype_ffr_crc, tvb, offset, 4,
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ENC_BIG_ENDIAN);
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offset += 4;
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proto_tree_add_item(skype_tree, hf_skype_ffr_enc_data, tvb, offset, -1,
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ENC_NA);
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offset = packet_length;
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break;
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case SKYPE_TYPE_NAT_INFO:
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proto_tree_add_item(skype_tree, hf_skype_natinfo_srcip, tvb, offset, 4,
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ENC_BIG_ENDIAN);
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skype_udp_info->global_src_ip = tvb_get_ipv4(tvb, offset);
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offset += 4;
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proto_tree_add_item(skype_tree, hf_skype_natinfo_dstip, tvb, offset, 4,
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ENC_BIG_ENDIAN);
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skype_udp_info->global_dst_ip = tvb_get_ipv4(tvb, offset);
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offset += 4;
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break;
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case SKYPE_TYPE_NAT_REPEAT:
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proto_tree_add_item(skype_tree, hf_skype_natrequest_srcip, tvb, offset, 4,
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ENC_BIG_ENDIAN);
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skype_udp_info->global_src_ip = tvb_get_ipv4(tvb, offset);
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offset += 4;
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proto_tree_add_item(skype_tree, hf_skype_natrequest_dstip, tvb, offset, 4,
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ENC_BIG_ENDIAN);
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skype_udp_info->global_dst_ip = tvb_get_ipv4(tvb, offset);
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offset += 4;
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break;
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case SKYPE_TYPE_AUDIO:
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proto_tree_add_item(skype_tree, hf_skype_audio_unk1, tvb, offset, -1,
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ENC_NA);
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offset = packet_length;
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break;
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case SKYPE_TYPE_UNKNOWN_F:
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proto_tree_add_item(skype_tree, hf_skype_unknown_f_unk1, tvb, offset, -1,
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ENC_NA);
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offset = packet_length;
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break;
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default:
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proto_tree_add_item(skype_tree, hf_skype_unknown_packet, tvb, offset, -1,
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ENC_NA);
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offset = packet_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 gboolean
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test_skype_udp(tvbuff_t *tvb)
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{
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/* Minimum of 3 bytes, check for valid message type */
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if (tvb_captured_length(tvb) > 3)
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{
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guint8 type = tvb_get_guint8(tvb, 2) & 0xF;
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if ( type == 0 ||
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/* FIXME: Extend this by minimum or exact length per message type */
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type == 2 ||
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type == 3 ||
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type == 5 ||
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type == 7 ||
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type == 0xd ||
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type == 0xf
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)
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{
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return TRUE;
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}
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}
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return FALSE;
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}
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static gboolean
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dissect_skype_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
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{
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if ( !test_skype_udp(tvb) ) {
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return FALSE;
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}
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dissect_skype_udp(tvb, pinfo, tree);
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return TRUE;
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}
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static int
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dissect_skype_static(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
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{
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/*
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* Don't test for valid packet - we only end here when
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* the user did a decode-as.
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*/
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if (pinfo->ptype == PT_UDP) {
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return dissect_skype_udp(tvb, pinfo, tree);
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} else if (pinfo->ptype == PT_TCP) {
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return dissect_skype_tcp(tvb, pinfo, tree);
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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_skype(void)
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{
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static hf_register_info hf[] = {
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/* Start of message fields */
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{ &hf_skype_som_id,
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{ "ID", "skype.som.id", FT_UINT16, BASE_HEX, NULL,
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0x0, "Message ID", HFILL }},
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{ &hf_skype_som_unk,
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{ "Unknown", "skype.som.unk", FT_UINT8, BASE_HEX, NULL,
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SKYPE_SOM_UNK_MASK, NULL, HFILL }},
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{ &hf_skype_som_type,
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{ "Type", "skype.som.type", FT_UINT8, BASE_HEX, VALS(skype_type_vals),
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SKYPE_SOM_TYPE_MASK, "Message type", HFILL }},
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/* Message body */
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/* Unknown_0 */
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{ &hf_skype_unknown_0_unk1,
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{ "Unknown1", "skype.unknown_0.unk1", FT_BYTES, BASE_NONE, NULL,
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0x0, NULL, HFILL }},
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/* Payload */
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{ &hf_skype_payload_iv,
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{ "IV", "skype.payload.iv", FT_UINT32, BASE_HEX, NULL,
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0x0, NULL, HFILL }},
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{ &hf_skype_payload_crc,
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{ "CRC", "skype.payload.crc", FT_UINT32, BASE_HEX, NULL,
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0x0, NULL, HFILL }},
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{ &hf_skype_payload_enc_data,
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{ "Enc Data", "skype.payload.encdata", FT_BYTES, BASE_NONE, NULL,
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0x0, NULL, HFILL }},
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/* Resend */
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{ &hf_skype_ffr_num,
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{ "Num", "skype.ffr.num", FT_UINT8, BASE_HEX, NULL,
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0x0, NULL, HFILL }},
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{ &hf_skype_ffr_unk1,
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{ "Unk1", "skype.ffr.unk1", FT_UINT32, BASE_HEX, NULL,
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0x0, NULL, HFILL }},
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{ &hf_skype_ffr_iv,
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{ "IV", "skype.ffr.iv", FT_UINT32, BASE_HEX, NULL,
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0x0, NULL, HFILL }},
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{ &hf_skype_ffr_crc,
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{ "CRC", "skype.ffr.crc", FT_UINT32, BASE_HEX, NULL,
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0x0, NULL, HFILL }},
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{ &hf_skype_ffr_enc_data,
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{ "Enc Data", "skype.ffr.encdata", FT_BYTES, BASE_NONE, NULL,
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0x0, NULL, HFILL }},
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/* Nat info */
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{ &hf_skype_natinfo_srcip,
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{ "Src IP", "skype.natinfo.srcip", FT_IPv4, BASE_NONE, NULL,
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0x0, "Global source IP", HFILL }},
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{ &hf_skype_natinfo_dstip,
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{ "Dst IP", "skype.natinfo.dstip", FT_UINT32, BASE_HEX, NULL,
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0x0, "Global destination IP", HFILL }},
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/* Nat request */
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{ &hf_skype_natrequest_srcip,
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{ "Src IP", "skype.natrequest.srcip", FT_IPv4, BASE_NONE, NULL,
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0x0, "Global source IP", HFILL }},
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{ &hf_skype_natrequest_dstip,
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{ "Dst IP", "skype.natrequest.dstip", FT_UINT32, BASE_HEX, NULL,
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0x0, NULL, HFILL }},
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/* Audio */
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{ &hf_skype_audio_unk1,
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{ "Unknown1", "skype.audio.unk1", FT_BYTES, BASE_NONE, NULL,
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0x0, NULL, HFILL }},
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/* Unknown_F */
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{ &hf_skype_unknown_f_unk1,
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{ "Unknown1", "skype.unknown_f.unk1", FT_BYTES, BASE_NONE, NULL,
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0x0, NULL, HFILL }},
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/* Unknown packet */
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{ &hf_skype_unknown_packet,
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{ "Unknown Packet", "skype.unknown_packet", FT_BYTES, BASE_NONE, NULL,
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0x0, NULL, HFILL }},
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};
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static gint *ett[] = {
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&ett_skype,
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};
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proto_skype = proto_register_protocol(PROTO_LONG_NAME, PROTO_SHORT_NAME, "skype");
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proto_register_field_array(proto_skype, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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}
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void
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proto_reg_handoff_skype(void)
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{
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dissector_handle_t skype_handle;
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skype_handle = create_dissector_handle(dissect_skype_static, proto_skype);
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dissector_add_for_decode_as_with_preference("tcp.port", skype_handle);
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dissector_add_for_decode_as_with_preference("udp.port", skype_handle);
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heur_dissector_add("udp", dissect_skype_heur, "Skype over UDP", "skype_udp", proto_skype, HEURISTIC_DISABLE);
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}
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/*
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* Editor modelines - http://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 8
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* tab-width: 8
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* indent-tabs-mode: t
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* End:
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*
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* vi: set shiftwidth=8 tabstop=8 noexpandtab:
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* :indentSize=8:tabSize=8:noTabs=false:
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*/
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