refactor: re-org packages

core/cs/protocol.go

@@ -0,0 +1,79 @@
+package cs
+
+import (
+	"time"
+
+	"github.com/lucas-clemente/quic-go"
+)
+
+const (
+	protocolVersion = uint8(3)
+	protocolTimeout = 10 * time.Second
+)
+
+type qError struct {
+	Code quic.ApplicationErrorCode
+	Msg  string
+}
+
+func (e qError) Send(c quic.Connection) error {
+	return c.CloseWithError(e.Code, e.Msg)
+}
+
+var (
+	qErrorGeneric  = qError{0, ""}
+	qErrorProtocol = qError{1, "protocol error"}
+	qErrorAuth     = qError{2, "auth error"}
+)
+
+type maxRate struct {
+	SendBPS uint64
+	RecvBPS uint64
+}
+
+type clientHello struct {
+	Rate    maxRate
+	AuthLen uint16 `struc:"sizeof=Auth"`
+	Auth    []byte
+}
+
+type serverHello struct {
+	OK         bool
+	Rate       maxRate
+	MessageLen uint16 `struc:"sizeof=Message"`
+	Message    string
+}
+
+type clientRequest struct {
+	UDP     bool
+	HostLen uint16 `struc:"sizeof=Host"`
+	Host    string
+	Port    uint16
+}
+
+type serverResponse struct {
+	OK           bool
+	UDPSessionID uint32
+	MessageLen   uint16 `struc:"sizeof=Message"`
+	Message      string
+}
+
+type udpMessage struct {
+	SessionID uint32
+	HostLen   uint16 `struc:"sizeof=Host"`
+	Host      string
+	Port      uint16
+	MsgID     uint16 // doesn't matter when not fragmented, but must not be 0 when fragmented
+	FragID    uint8  // doesn't matter when not fragmented, starts at 0 when fragmented
+	FragCount uint8  // must be 1 when not fragmented
+	DataLen   uint16 `struc:"sizeof=Data"`
+	Data      []byte
+}
+
+func (m udpMessage) HeaderSize() int {
+	return 4 + 2 + len(m.Host) + 2 + 2 + 1 + 1 + 2
+}
+
+func (m udpMessage) Size() int {
+	return m.HeaderSize() + len(m.Data)
+}