TUN-4597: Add a QUIC server skeleton

- Added a QUIC server to accept streams
- Unit test for this server also tests ALPN
- Temporary echo capability for HTTP ConnectionType

vendor/github.com/lucas-clemente/quic-go/internal/protocol/protocol.go

@@ -0,0 +1,97 @@
+package protocol
+
+import (
+	"fmt"
+	"time"
+)
+
+// The PacketType is the Long Header Type
+type PacketType uint8
+
+const (
+	// PacketTypeInitial is the packet type of an Initial packet
+	PacketTypeInitial PacketType = 1 + iota
+	// PacketTypeRetry is the packet type of a Retry packet
+	PacketTypeRetry
+	// PacketTypeHandshake is the packet type of a Handshake packet
+	PacketTypeHandshake
+	// PacketType0RTT is the packet type of a 0-RTT packet
+	PacketType0RTT
+)
+
+func (t PacketType) String() string {
+	switch t {
+	case PacketTypeInitial:
+		return "Initial"
+	case PacketTypeRetry:
+		return "Retry"
+	case PacketTypeHandshake:
+		return "Handshake"
+	case PacketType0RTT:
+		return "0-RTT Protected"
+	default:
+		return fmt.Sprintf("unknown packet type: %d", t)
+	}
+}
+
+type ECN uint8
+
+const (
+	ECNNon ECN = iota // 00
+	ECT1              // 01
+	ECT0              // 10
+	ECNCE             // 11
+)
+
+// A ByteCount in QUIC
+type ByteCount int64
+
+// MaxByteCount is the maximum value of a ByteCount
+const MaxByteCount = ByteCount(1<<62 - 1)
+
+// InvalidByteCount is an invalid byte count
+const InvalidByteCount ByteCount = -1
+
+// A StatelessResetToken is a stateless reset token.
+type StatelessResetToken [16]byte
+
+// MaxPacketBufferSize maximum packet size of any QUIC packet, based on
+// ethernet's max size, minus the IP and UDP headers. IPv6 has a 40 byte header,
+// UDP adds an additional 8 bytes.  This is a total overhead of 48 bytes.
+// Ethernet's max packet size is 1500 bytes,  1500 - 48 = 1452.
+const MaxPacketBufferSize ByteCount = 1452
+
+// MinInitialPacketSize is the minimum size an Initial packet is required to have.
+const MinInitialPacketSize = 1200
+
+// MinUnknownVersionPacketSize is the minimum size a packet with an unknown version
+// needs to have in order to trigger a Version Negotiation packet.
+const MinUnknownVersionPacketSize = MinInitialPacketSize
+
+// MinStatelessResetSize is the minimum size of a stateless reset packet that we send
+const MinStatelessResetSize = 1 /* first byte */ + 20 /* max. conn ID length */ + 4 /* max. packet number length */ + 1 /* min. payload length */ + 16 /* token */
+
+// MinConnectionIDLenInitial is the minimum length of the destination connection ID on an Initial packet.
+const MinConnectionIDLenInitial = 8
+
+// DefaultAckDelayExponent is the default ack delay exponent
+const DefaultAckDelayExponent = 3
+
+// MaxAckDelayExponent is the maximum ack delay exponent
+const MaxAckDelayExponent = 20
+
+// DefaultMaxAckDelay is the default max_ack_delay
+const DefaultMaxAckDelay = 25 * time.Millisecond
+
+// MaxMaxAckDelay is the maximum max_ack_delay
+const MaxMaxAckDelay = (1<<14 - 1) * time.Millisecond
+
+// MaxConnIDLen is the maximum length of the connection ID
+const MaxConnIDLen = 20
+
+// InvalidPacketLimitAES is the maximum number of packets that we can fail to decrypt when using
+// AEAD_AES_128_GCM or AEAD_AES_265_GCM.
+const InvalidPacketLimitAES = 1 << 52
+
+// InvalidPacketLimitChaCha is the maximum number of packets that we can fail to decrypt when using AEAD_CHACHA20_POLY1305.
+const InvalidPacketLimitChaCha = 1 << 36