quic

const (
	PaddingFrame         = 0x0
	ResetStreamFrame     = 0x1
	ConnectionCloseFrame = 0x2
	GoAwayFrame          = 0x3
	WindowUpdateFrame    = 0x4
	BlockedFrame         = 0x5
	StopWaitingFrame     = 0x6
	PingFrame            = 0x7

	StreamFrame                 = 0x80
	AckFrameMask                = 0xC0
	AckFrame                    = 0x40
	CongestionFeedbackFrameMask = 0xE0
	CongestionFeedbackFrame     = 0x20
)

const (
	StreamIDMask = 0x03
	OffsetMask   = 0x1C
	DataLenMask  = 0x20
	FinMask      = 0x40
)

const (
	SequenceNumberDeltaLenMask           = 0x03
	LargestObservedSequenceNumberLenMask = 0xC
)

const (
	// QuicVersion - LSB 0x1 has value 1 iff the packet contains a Quic Version.  This bit must be set by a client in all packets until confirmation from a server arrives agreeing to the proposed version is received by the client.  A server indicates agreement on a version by sending packets without setting this bit.
	QuicVersion = 0x1
	// PublicReset - Bit at location, 0x2, is set to indicate that the packet is a Public Reset packet.
	PublicReset = 0x2
	// DataPacket is the bitmask for a data packet. If version and public reset aren't set.
	DataPacket = 0x3

	// ConnIDBitMask - Pair of bits, included in 0xC, together indicate the size of the connection ID that is present in the packet, but should be set to set to 0xC in all packets until agreeably negotiated to a different value, for a given direction (e.g., client may request fewer bytes of the connection id be presented).  Within this 2 bit mask:
	ConnIDBitMask = 0xC
	ConnID8Bytes  = 0xC
	ConnID4Bytes  = 0x8
	ConnID1Byte   = 0x4
	ConnIDOmmited = 0x0

	// SequenceNumberBitMask - Pair of bits included in 0x30 indicate the number of low-order-bytes of the packet sequence number that are present in each packet.  Within this 2 bit mask:
	SequenceNumberBitMask = 0x30
	SequenceNumber6Bytes  = 0x30
	SequenceNumber4Bytes  = 0x20
	SequenceNumber2Bytes  = 0x10
	SequenceNumber1Byte   = 0x00
)

const (
	// FlagEntropy - for data packets, signifies that this packet contains the 1 bit of entropy, for fec packets, contains the xor of the entropy of protected packets.
	FlagEntropy = 0x01
	// FlagFECGroup - indicates whether the fec byte is present.
	FlagFECGroup = 0x02
	// FlagFEC - signifies that this packet represents an FEC packet.
	FlagFEC = 0x04
)