/* packet-rdpudp.c

 * Routines for RDP multi transport packet dissection

 * Copyright 2021, David Fort

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

 * SPDX-License-Identifier: GPL-2.0-or-later

 */

#include "config.h"

#include <epan/packet.h>

#include <epan/prefs.h>

#include <epan/expert.h>

#include <epan/conversation.h>

#include "packet-rdp.h"

#include "packet-rdpudp.h"

#define PNAME  "Remote Desktop Protocol Multi-transport"

#define PSNAME "RDPMT"

#define PFNAME "rdpmt"

void proto_register_rdpmt(void);

void proto_reg_handoff_rdpmt(void);

static dissector_handle_t rdpmt_handle;

static int proto_rdpmt;

static int hf_rdpmt_action;

static int hf_rdpmt_flags;

static int hf_rdpmt_payload_len;

static int hf_rdpmt_header_len;

static int hf_rdpmt_subheader_len;

static int hf_rdpmt_subheader_type;

static int hf_rdpmt_createreq_reqId;

static int hf_rdpmt_createreq_reserved;

static int hf_rdpmt_createreq_cookie;

static int hf_rdpmt_createresp_hrResponse;

static int ett_rdpmt;

static int ett_rdpudp_subheaders;

static int ett_rdpmt_create_req;

static int ett_rdpmt_create_resp;

static int ett_rdpmt_data;

static dissector_handle_t drdynvcDissector;

static const value_string rdpmt_action_vals[] = {

  { 0x00, "CreateRequest"},

  { 0x01, "CreateResponse"},

  { 0x02, "Data"},

  { 0x00, NULL}

};

static const value_string rdpmt_subheader_type_vals[] = {

  { 0x0, "auto detect request" },

  { 0x1, "auto detect response" },

  { 0x0, NULL}

};

enum {

  RDPMT_TUNNEL_CREATE_REQ = 0,

  RDPMT_TUNNEL_CREATE_RESP = 1,

  RDPMT_TUNNEL_DATA = 2,

};

static int

dissect_rdpmt(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void *data _U_)

{

  proto_item *item;

  proto_tree *tree, *subtree;

  uint8_t action, subheader_len;

  uint16_t payload_len;

  int offset = 0;

  item = proto_tree_add_item(parent_tree, proto_rdpmt, tvb, 0, -1, ENC_NA);

  tree = proto_item_add_subtree(item, ett_rdpmt);

  action = tvb_get_uint8(tvb, offset) & 0x0f;

  proto_tree_add_item(tree, hf_rdpmt_action, tvb, offset, 1, ENC_NA);

  proto_tree_add_item(tree, hf_rdpmt_flags, tvb, offset, 1, ENC_NA);

  offset++;

  payload_len = tvb_get_uint16(tvb, offset, ENC_LITTLE_ENDIAN);

  proto_tree_add_item(tree, hf_rdpmt_payload_len, tvb, offset, 2, ENC_LITTLE_ENDIAN);

  offset += 2;

  subheader_len = tvb_get_uint8(tvb, offset);

  proto_tree_add_item(tree, hf_rdpmt_header_len, tvb, offset, 1, ENC_NA);

  offset += 1;

  if (subheader_len > 4) {

    tvbuff_t *subheaders = tvb_new_subset_length(tvb,  offset, subheader_len-4);

    proto_tree *subheaders_tree = proto_tree_add_subtree(tree, tvb, offset, -1, ett_rdpudp_subheaders, NULL, "SubHeaders");

    dissect_rdp_bandwidth_req(subheaders, 0, pinfo, subheaders_tree, !!rdp_isServerAddressTarget(pinfo));

  }

  offset += subheader_len - 4;

  switch (action) {

  case RDPMT_TUNNEL_CREATE_REQ: {

    uint8_t cookie[16];

    uint32_t reqId;

    conversation_t *conv = find_or_create_conversation(pinfo);

    col_set_str(pinfo->cinfo, COL_INFO, "TunnelCreateRequest");

    subtree = proto_tree_add_subtree(tree, tvb, offset, payload_len, ett_rdpmt_create_req, NULL, "TunnelCreateRequest");

    proto_tree_add_item(subtree, hf_rdpmt_createreq_reqId, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    reqId = tvb_get_uint32(tvb, offset, ENC_LITTLE_ENDIAN);

    offset += 4;

    proto_tree_add_item(subtree, hf_rdpmt_createreq_reserved, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    proto_tree_add_item(subtree, hf_rdpmt_createreq_cookie, tvb, offset, 16, ENC_NA);

    tvb_memcpy(tvb, cookie, offset, 16);

    offset += 4;

    rdp_transport_set_udp_conversation(pinfo, rdpudp_is_reliable_transport(pinfo), reqId, cookie, conv);

    break;

  }

  case RDPMT_TUNNEL_CREATE_RESP:

    col_set_str(pinfo->cinfo, COL_INFO, "TunnelCreateResponse");

    subtree = proto_tree_add_subtree(tree, tvb, offset, payload_len, ett_rdpmt_create_resp, NULL, "TunnelCreateResponse");

    proto_tree_add_item(subtree, hf_rdpmt_createresp_hrResponse, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    break;

  case RDPMT_TUNNEL_DATA:

    if (payload_len) {

      tvbuff_t *payload = tvb_new_subset_length(tvb, offset, payload_len);

      subtree = proto_tree_add_subtree(tree, tvb, offset, -1, ett_rdpmt_data, NULL, "Data");

      call_dissector(drdynvcDissector, payload, pinfo, subtree);

    }

    break;

  }

  return offset;

}

void

proto_register_rdpmt(void) {

  /* List of fields */

  static hf_register_info hf[] = {

    {&hf_rdpmt_action,

    {"Action", "rdpmt.action", FT_UINT8, BASE_HEX, VALS(rdpmt_action_vals), 0x0F, NULL, HFILL}

    },

    {&hf_rdpmt_flags,

    {"Flags", "rdpmt.flags", FT_UINT8, BASE_HEX, NULL, 0xF0, NULL, HFILL}

    },

    {&hf_rdpmt_payload_len,

    {"Payload length", "rdpmt.payloadlen", FT_UINT16, BASE_DEC, NULL, 0, NULL, HFILL}

    },

    {&hf_rdpmt_header_len,

    {"Header length", "rdpmt.headerlen", FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL}

    },

    {&hf_rdpmt_subheader_len,

    {"Sub header length", "rdpmt.subheaderlen", FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL}

    },

    {&hf_rdpmt_subheader_type,

    {"Sub header type", "rdpmt.subheadertype", FT_UINT8, BASE_HEX, VALS(rdpmt_subheader_type_vals), 0, NULL, HFILL}

    },

    {&hf_rdpmt_createreq_reqId,

    {"RequestID", "rdpmt.createrequest.requestid", FT_UINT32, BASE_HEX, NULL, 0, NULL, HFILL}

    },

    {&hf_rdpmt_createreq_reserved,

    {"Reserved", "rdpmt.createrequest.reserved", FT_UINT32, BASE_HEX, NULL, 0, NULL, HFILL}

    },

    {&hf_rdpmt_createreq_cookie,

    {"Security cookie", "rdpmt.createrequest.cookie", FT_BYTES, BASE_NONE, NULL, 0, NULL, HFILL}

    },

    {&hf_rdpmt_createresp_hrResponse,

    {"hrResponse", "rdpmt.createresponse.hrresponse", FT_INT32, BASE_DEC, NULL, 0, NULL, HFILL}

    }

  };

  /* List of subtrees */

  static int *ett[] = {

    &ett_rdpmt,

    &ett_rdpudp_subheaders,

    &ett_rdpmt_create_req,

    &ett_rdpmt_create_resp,

    &ett_rdpmt_data

  };

  /* Register protocol */

  proto_rdpmt = proto_register_protocol(PNAME, PSNAME, PFNAME);

  /* Register fields and subtrees */

  proto_register_field_array(proto_rdpmt, hf, array_length(hf));

  proto_register_subtree_array(ett, array_length(ett));

  rdpmt_handle = register_dissector("rdpmt", dissect_rdpmt, proto_rdpmt);

}

static bool

rdpmt_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)

{

  uint8_t action, header_len;

  uint16_t payload_len;

  if (tvb_reported_length(tvb) <= 4)

    return false;

  action = tvb_get_uint8(tvb, 0);

  if (action > 2)

    return false;

  payload_len = tvb_get_uint16(tvb, 1, ENC_LITTLE_ENDIAN);

  header_len = tvb_get_uint8(tvb, 3);

  if ((header_len < 4UL) || (tvb_reported_length_remaining(tvb, header_len) < payload_len))

    return false;

  if (header_len > 4) {

    uint8_t subheader_len, subheader_type;

    if(header_len < 6)

      return false;

    subheader_len = tvb_get_uint8(tvb, 4);

    if ((subheader_len < 2) || (subheader_len > header_len-4))

      return false;

    subheader_type = tvb_get_uint8(tvb, 5);

    if (subheader_type > 1) /* AUTODETECT_REQUEST or AUTODETECT_RESPONSE */

      return false;

  }

  return dissect_rdpmt(tvb, pinfo, tree, data) > 0;

}

void

proto_reg_handoff_rdpmt(void)

{

  drdynvcDissector = find_dissector("rdp_drdynvc");

  heur_dissector_add("tls", rdpmt_heur, "RDP MultiTransport", "rdpmt_tls_", proto_rdpmt, true);

  heur_dissector_add("dtls", rdpmt_heur, "RDP MultiTransport", "rdpmt_dtls", proto_rdpmt, true);

}

/*

 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html

 *

 * 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:

 */