make handshake and crypto internal packages

internal/crypto/null_aead_fnv128a.go

@@ -0,0 +1,76 @@
+package crypto
+
+import (
+	"encoding/binary"
+	"errors"
+
+	"github.com/lucas-clemente/fnv128a"
+	"github.com/lucas-clemente/quic-go/internal/protocol"
+)
+
+// nullAEAD handles not-yet encrypted packets
+type nullAEADFNV128a struct {
+	perspective protocol.Perspective
+	version     protocol.VersionNumber
+}
+
+var _ AEAD = &nullAEADFNV128a{}
+
+// Open and verify the ciphertext
+func (n *nullAEADFNV128a) Open(dst, src []byte, packetNumber protocol.PacketNumber, associatedData []byte) ([]byte, error) {
+	if len(src) < 12 {
+		return nil, errors.New("NullAEAD: ciphertext cannot be less than 12 bytes long")
+	}
+
+	hash := fnv128a.New()
+	hash.Write(associatedData)
+	hash.Write(src[12:])
+	if n.version >= protocol.Version37 {
+		if n.perspective == protocol.PerspectiveServer {
+			hash.Write([]byte("Client"))
+		} else {
+			hash.Write([]byte("Server"))
+		}
+	}
+	testHigh, testLow := hash.Sum128()
+
+	low := binary.LittleEndian.Uint64(src)
+	high := binary.LittleEndian.Uint32(src[8:])
+
+	if uint32(testHigh&0xffffffff) != high || testLow != low {
+		return nil, errors.New("NullAEAD: failed to authenticate received data")
+	}
+	return src[12:], nil
+}
+
+// Seal writes hash and ciphertext to the buffer
+func (n *nullAEADFNV128a) Seal(dst, src []byte, packetNumber protocol.PacketNumber, associatedData []byte) []byte {
+	if cap(dst) < 12+len(src) {
+		dst = make([]byte, 12+len(src))
+	} else {
+		dst = dst[:12+len(src)]
+	}
+
+	hash := fnv128a.New()
+	hash.Write(associatedData)
+	hash.Write(src)
+
+	if n.version >= protocol.Version37 {
+		if n.perspective == protocol.PerspectiveServer {
+			hash.Write([]byte("Server"))
+		} else {
+			hash.Write([]byte("Client"))
+		}
+	}
+
+	high, low := hash.Sum128()
+
+	copy(dst[12:], src)
+	binary.LittleEndian.PutUint64(dst, low)
+	binary.LittleEndian.PutUint32(dst[8:], uint32(high))
+	return dst
+}
+
+func (n *nullAEADFNV128a) Overhead() int {
+	return 12
+}