text: // SoftEther VPN Source Code - Developer Edition Master Branch
  // Cedar Communication Module
  
  
  // UdpAccel.h
  // Header of UdpAccel.c
  
  #ifndef	UDPACCEL_H
  #define	UDPACCEL_H
  
  // Constants
  #define	UDP_ACCELERATION_COMMON_KEY_SIZE_V1	20			// V1: Common key size
  #define	UDP_ACCELERATION_PACKET_KEY_SIZE_V1	20			// V1: Key size for the packet
  #define	UDP_ACCELERATION_PACKET_IV_SIZE_V1	20			// V1: IV size for the packet
  
  #define	UDP_ACCELERATION_COMMON_KEY_SIZE_V2	128			// V2: Common key size
  #define	UDP_ACCELERATION_PACKET_IV_SIZE_V2	12			// V2: IV size for the packet
  #define	UDP_ACCELERATION_PACKET_MAC_SIZE_V2	16			// V2: MAC size for the packet
  
  #define	UDP_ACCELERATION_TMP_BUF_SIZE		2048		// Temporary buffer size
  #define	UDP_ACCELERATION_WINDOW_SIZE_MSEC	(30 * 1000)	// Receive window size (in milliseconds)
  
  #define	UDP_ACCELERATION_SUPPORTED_MAX_PAYLOAD_SIZE	1600	// Maximum supported payload size
  #define	UDP_ACCELERATION_MAX_PADDING_SIZE	32			// Maximum padding size
  
  #define	UDP_ACCELERATION_REQUIRE_CONTINUOUS	(10 * 1000)	// Not to use if stable communication is not continued at least for this time
  
  // Time constant for Build 8534 or earlier
  #define	UDP_ACCELERATION_KEEPALIVE_INTERVAL_MIN	(1 * 1000)	// Keep Alive Interval (minimum)
  #define	UDP_ACCELERATION_KEEPALIVE_INTERVAL_MAX	(3 * 1000)	// Keep Alive Interval (maximum)
  #define	UDP_ACCELERATION_KEEPALIVE_TIMEOUT		(9 * 1000)	// Time to disconnect time by non-communication
  
  // Time constant for Build 8535 or later
  #define	UDP_ACCELERATION_KEEPALIVE_INTERVAL_MIN_FAST	(500)	// Keep Alive Interval (minimum)
  #define	UDP_ACCELERATION_KEEPALIVE_INTERVAL_MAX_FAST	(1000)	// Keep Alive Interval (maximum)
  #define	UDP_ACCELERATION_KEEPALIVE_TIMEOUT_FAST			(2100)	// Time to disconnect time by non-communication
  
  // Range of port numbers
  #define	UDP_SERVER_PORT_LOWER				40000		// Minimum port
  #define	UDP_SERVER_PORT_HIGHER				44999		// Maximum port
  
  // NAT-T port signature to be embedded in the Keep Alive of the session
  #define	UDP_NAT_T_PORT_SIGNATURE_IN_KEEP_ALIVE			"NATT_MY_PORT"
  
  // UDP Acceleration Mode
  struct UDP_ACCEL
  {
  	CEDAR *Cedar;										// Cedar
  	bool NoNatT;										// Not to communicate with the NAT-T server (To communicate with the query server instead)
  	bool ClientMode;									// Whether client mode
  	bool IsInCedarPortList;								// Whether included in the port list of the Cedar
  	UINT64 Now;											// Current time
  	CIPHER *CipherEncrypt;								// Encryption context
  	CIPHER *CipherDecrypt;								// Decryption context
  	UCHAR MyKey[UDP_ACCELERATION_COMMON_KEY_SIZE_V1];	// Send-direction common key
  	UCHAR YourKey[UDP_ACCELERATION_COMMON_KEY_SIZE_V1];	// Receive-direction common key
  	SOCK *UdpSock;										// UDP socket
  	UINT MyPort;										// My port number
  	UINT YourPort;										// Port number of the other party
  	IP MyIp;											// My IP address
  	IP YourIp;											// IP address of the other party
  	IP YourIp2;											// IP address of the other party (second)
  	bool IsIPv6;										// Whether it's an IPv6
  	UCHAR TmpBuf[UDP_ACCELERATION_TMP_BUF_SIZE];		// Temporary buffer
  	UINT64 LastRecvYourTick;							// Opponent's tick value of the last reception
  	UINT64 LastRecvMyTick;								// My tick value of the last reception
  	QUEUE *RecvBlockQueue;								// Reception block queue
  	bool UseHMac;										// Flag to use the HMAC
  	bool PlainTextMode;									// No encryption
  	UINT64 LastSetSrcIpAndPortTick;						// Opponent's tick ??value at the time of storing the IP address and port number of the opponent at the end
  	UINT64 LastRecvTick;								// Tick when data has received at the end
  	UINT64 NextSendKeepAlive;							// Next time to send a KeepAlive packet
  	UCHAR NextIv[UDP_ACCELERATION_PACKET_IV_SIZE_V1];	// IV to be used next
  	UINT MyCookie;										// My cookie
  	UINT YourCookie;									// Cookie of the other party
  	bool Inited;										// Initialized flag
  	UINT Mss;											// Optimal MSS
  	UINT MaxUdpPacketSize;								// Get the maximum transmittable UDP size
  	LOCK *NatT_Lock;									// Lock the IP address field of NAT-T server
  	IP NatT_IP;											// IP address of the NAT-T server
  	THREAD *NatT_GetIpThread;							// IP address acquisition thread of NAT-T server
  	bool NatT_Halt;										// Halting flag of IP address acquisition thread of NAT-T server
  	EVENT *NatT_HaltEvent;								// Halting event of IP address acquisition thread of NAT-T server
  	UINT64 NextPerformNatTTick;							// Time to communicate with NAT-T server next time
  	UINT CommToNatT_NumFail;							// Number of failures to communicate with NAT-T server
  	UINT MyPortByNatTServer;							// Self port number which is received from the NAT-T server
  	bool MyPortByNatTServerChanged;						// The self port number which is received from the NAT-T server changes
  	UINT YourPortByNatTServer;							// Port number of the opponent that was found via the NAT-T server
  	bool YourPortByNatTServerChanged;					// Port number of the opponent that was found via the NAT-T server has been changed
  	bool FatalError;									// A fatal error occurred
  	bool NatT_IP_Changed;								// IP address of the NAT-T server has changed
  	UINT64 NatT_TranId;									// Transaction ID to be exchanged with the NAT-T server
  	bool IsReachedOnce;									// It is true if it succeeds in mutual transmission and reception of packets at least once
  	UINT64 CreatedTick;									// Object creation time
  	bool FastDetect;									// Fast disconnection detection mode
  	UINT64 FirstStableReceiveTick;						// Start time of current stable continued receivable period
  	bool UseSuperRelayQuery;							// Use the super relay query
  	bool UseUdpIpQuery;									// Use the self IP address query by UDP
  	IP UdpIpQueryHost;									// Host for the self IP address query by UDP
  	UINT UdpIpQueryPort;								// Port number for self IP address for query by UDP
  	UCHAR UdpIpQueryPacketData[16];						// Query packet data (final transmission)
  	UINT UdpIpQueryPacketSize;							// Query packet data size (final transmission)
  	UCHAR UdpHostUniqueKey[SHA1_SIZE];					// Unique key for UDP self endpoint query
  	UINT Version;										// Version
  	UCHAR MyKey_V2[UDP_ACCELERATION_COMMON_KEY_SIZE_V2];	// Send-direction common key (version 2)
  	UCHAR NextIv_V2[UDP_ACCELERATION_PACKET_IV_SIZE_V2];	// IV to be used next (version 2)
  	bool ReadRawFlagMode;								// Read raw flag mode
  };
  
  // Function prototype
  UDP_ACCEL *NewUdpAccel(CEDAR *cedar, IP *ip, bool client_mode, bool random_port, bool no_nat_t);
  void FreeUdpAccel(UDP_ACCEL *a);
  bool UdpAccelInitClient(UDP_ACCEL *a, UCHAR *server_key, IP *server_ip, UINT server_port, UINT server_cookie, UINT client_cookie, IP *server_ip_2);
  bool UdpAccelInitServer(UDP_ACCEL *a, UCHAR *client_key, IP *client_ip, UINT client_port, IP *client_ip_2);
  void UdpAccelPoll(UDP_ACCEL *a);
  void UdpAccelSetTick(UDP_ACCEL *a, UINT64 tick64);
  BLOCK *UdpAccelProcessRecvPacket(UDP_ACCEL *a, UCHAR *buf, UINT size, IP *src_ip, UINT src_port);
  void UdpAccelCalcKeyV1(UCHAR *key, UCHAR *common_key, UCHAR *iv);
  bool UdpAccelIsSendReady(UDP_ACCEL *a, bool check_keepalive);
  void UdpAccelSend(UDP_ACCEL *a, UCHAR *data, UINT data_size, UCHAR flag, UINT max_size, bool high_priority);
  void UdpAccelSendBlock(UDP_ACCEL *a, BLOCK *b);
  UINT UdpAccelCalcMss(UDP_ACCEL *a);
  void NatT_GetIpThread(THREAD *thread, void *param);
  
  #endif	// UDPACCEL_H
  
  
  