dtls_srtp_transport.h

/*

 *  Copyright 2017 The WebRTC project authors. All Rights Reserved.

 *  Use of this source code is governed by a BSD-style license

 *  that can be found in the LICENSE file in the root of the source

 *  tree. An additional intellectual property rights grant can be found

 *  in the file PATENTS.  All contributing project authors may

 *  be found in the AUTHORS file in the root of the source tree.

*/

#ifndef PC_DTLS_SRTP_TRANSPORT_H_

#define PC_DTLS_SRTP_TRANSPORT_H_

#include <functional>

#include <string>

#include <vector>

#include "absl/types/optional.h"

#include "api/dtls_transport_interface.h"

#include "api/rtc_error.h"

#include "p2p/base/dtls_transport_internal.h"

#include "p2p/base/packet_transport_internal.h"

#include "pc/srtp_transport.h"

#include "rtc_base/buffer.h"

namespace webrtc {

// The subclass of SrtpTransport is used for DTLS-SRTP. When the DTLS handshake

// is finished, it extracts the keying materials from DtlsTransport and

// configures the SrtpSessions in the base class.

class DtlsSrtpTransport : public SrtpTransport {

 public:

  DtlsSrtpTransport(bool rtcp_mux_enabled, const FieldTrialsView& field_trials);

  // Set P2P layer RTP/RTCP DtlsTransports. When using RTCP-muxing,

  // `rtcp_dtls_transport` is null.

  void SetDtlsTransports(cricket::DtlsTransportInternal* rtp_dtls_transport,

                         cricket::DtlsTransportInternal* rtcp_dtls_transport);

  void SetRtcpMuxEnabled(bool enable) override;

  // Set the header extension ids that should be encrypted.

  void UpdateSendEncryptedHeaderExtensionIds(

      const std::vector<int>& send_extension_ids);

  void UpdateRecvEncryptedHeaderExtensionIds(

      const std::vector<int>& recv_extension_ids);

  void SetOnDtlsStateChange(std::function<void(void)> callback);

  // If `active_reset_srtp_params_` is set to be true, the SRTP parameters will

  // be reset whenever the DtlsTransports are reset.

  void SetActiveResetSrtpParams(bool active_reset_srtp_params) {

    active_reset_srtp_params_ = active_reset_srtp_params;

 private:

  bool IsDtlsActive();

  bool IsDtlsConnected();

  bool IsDtlsWritable();

  bool DtlsHandshakeCompleted();

  void MaybeSetupDtlsSrtp();

  void SetupRtpDtlsSrtp();

  void SetupRtcpDtlsSrtp();

  bool ExtractParams(cricket::DtlsTransportInternal* dtls_transport,

                     int* selected_crypto_suite,

                     rtc::ZeroOnFreeBuffer<unsigned char>* send_key,

                     rtc::ZeroOnFreeBuffer<unsigned char>* recv_key);

  void SetDtlsTransport(cricket::DtlsTransportInternal* new_dtls_transport,

                        cricket::DtlsTransportInternal** old_dtls_transport);

  void SetRtpDtlsTransport(cricket::DtlsTransportInternal* rtp_dtls_transport);

  void SetRtcpDtlsTransport(

      cricket::DtlsTransportInternal* rtcp_dtls_transport);

  void OnDtlsState(cricket::DtlsTransportInternal* dtls_transport,

                   DtlsTransportState state);

  // Override the SrtpTransport::OnWritableState.

  void OnWritableState(rtc::PacketTransportInternal* packet_transport) override;

  // Owned by the TransportController.

  cricket::DtlsTransportInternal* rtp_dtls_transport_ = nullptr;

  cricket::DtlsTransportInternal* rtcp_dtls_transport_ = nullptr;

  // The encrypted header extension IDs.

  absl::optional<std::vector<int>> send_extension_ids_;

  absl::optional<std::vector<int>> recv_extension_ids_;

  bool active_reset_srtp_params_ = false;

  std::function<void(void)> on_dtls_state_change_;

};

}  // namespace webrtc

#endif  // PC_DTLS_SRTP_TRANSPORT_H_