/* Copyright(C) 2007-2014 VoIP objects (voipobjects.com)
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef __MT_SRTP_HELPER_H
#define __MT_SRTP_HELPER_H

#include <string>
#include <vector>
#include <map>

#include "srtp/include/srtp.h"
#include "../helper/HL_Sync.h"
#include "../helper/HL_ByteBuffer.h"

#define SRTP_SUITE_NAME_2 "AES_CM_256_HMAC_SHA1_80"
#define SRTP_SUITE_NAME_1 "AES_CM_128_HMAC_SHA1_80"

enum SrtpSuite
{
  SRTP_NONE,
  SRTP_AES_128_AUTH_80,
  SRTP_AES_256_AUTH_80,
  SRTP_LAST = SRTP_AES_256_AUTH_80
};

typedef std::pair<PByteBuffer, PByteBuffer> SrtpKeySalt;
typedef std::pair<unsigned, srtp_policy_t> SrtpStream;

class SrtpSession
{
public:
  SrtpSession();
  ~SrtpSession();
  
  enum SsrcDirection
  {
    sdIncoming,
    sdOutgoing
  };
  SrtpKeySalt&     outgoingKey(SrtpSuite suite);

  void open(ByteBuffer& incomingKey, SrtpSuite suite);
  void close();
  bool active();

  /* bufferPtr is RTP packet data i.e. header + payload. Buffer must be big enough to hold encrypted data. */
  bool protectRtp(void* buffer, int* length);
  bool protectRtcp(void* buffer, int* length);
  bool unprotectRtp(void* buffer, int* length);
  bool unprotectRtcp(void* buffer, int* length);
  

  static void initSrtp();
protected:
  srtp_t          mInboundSession,
                  mOutboundSession;

  SrtpKeySalt     mIncomingKey,
                  mOutgoingKey[SRTP_LAST];
  srtp_policy_t   mInboundPolicy;
  srtp_policy_t   mOutboundPolicy;
  SrtpSuite       mSuite;

  typedef std::map<unsigned, SrtpStream> SrtpStreamMap;
  SrtpStreamMap mIncomingMap, mOutgoingMap;
  Mutex mGuard;

  void addSsrc(unsigned ssrc, SsrcDirection d);
};

#endif