internal/message: Be more consistent with original RakNet in field na…

…ming.

conn.go

@@ -157,7 +157,7 @@ func (conn *Conn) startTicking() {
 			}
 			if i%5 == 0 {
 				// Ping the other end periodically to prevent timeouts.
-				_ = conn.send(&message.ConnectedPing{ClientTimestamp: timestamp()})
+				_ = conn.send(&message.ConnectedPing{PingTime: timestamp()})
 
 				conn.mu.Lock()
 				if t.Sub(*conn.lastActivity.Load()) > time.Second*5+conn.retransmission.rtt(t)*2 {

dial.go

@@ -136,7 +136,7 @@ func (dialer Dialer) PingContext(ctx context.Context, address string) (response
 	}
 	defer conn.Close()
 
-	data, _ := (&message.UnconnectedPing{SendTimestamp: timestamp(), ClientGUID: atomic.AddInt64(&dialerID, 1)}).MarshalBinary()
+	data, _ := (&message.UnconnectedPing{PingTime: timestamp(), ClientGUID: atomic.AddInt64(&dialerID, 1)}).MarshalBinary()
 	if _, err := conn.Write(data); err != nil {
 		return nil, dialer.error("ping", err)
 	}
@@ -230,9 +230,11 @@ func (dialer Dialer) DialContext(ctx context.Context, address string) (*Conn, er
 	return dialer.connect(ctx, cs)
 }
 
+// dial finishes the RakNet connection sequence and returns a Conn if
+// successful.
 func (dialer Dialer) connect(ctx context.Context, state *connState) (*Conn, error) {
 	conn := newConn(internal.ConnToPacketConn(state.conn), state.raddr, state.mtu, dialerConnectionHandler{})
-	if err := conn.send((&message.ConnectionRequest{ClientGUID: state.id, RequestTimestamp: timestamp()})); err != nil {
+	if err := conn.send((&message.ConnectionRequest{ClientGUID: state.id, RequestTime: timestamp()})); err != nil {
 		return nil, dialer.error("dial", fmt.Errorf("send connection request: %w", err))
 	}
 
@@ -316,16 +318,16 @@ func (state *connState) discoverMTU(ctx context.Context) error {
 			if err := response.UnmarshalBinary(b[1:n]); err != nil {
 				return fmt.Errorf("read open connection reply 1: %w", err)
 			}
-			state.serverSecurity, state.cookie = response.Secure, response.Cookie
-			if response.ServerGUID == 0 || response.ServerPreferredMTUSize < 400 || response.ServerPreferredMTUSize > 1500 {
+			state.serverSecurity, state.cookie = response.ServerHasSecurity, response.Cookie
+			if response.ServerGUID == 0 || response.MTU < 400 || response.MTU > 1500 {
 				// This is an awful hack we cooked up to deal with OVH 'DDoS'
 				// protection. For some reason they send a broken MTU size
 				// first. Sending a Request2 followed by a Request1 deals with
 				// this.
-				state.openConnectionRequest2(response.ServerPreferredMTUSize)
+				state.openConnectionRequest2(response.MTU)
 				continue
 			}
-			state.mtu = response.ServerPreferredMTUSize
+			state.mtu = response.MTU
 			return nil
 		case message.IDIncompatibleProtocolVersion:
 			response := &message.IncompatibleProtocolVersion{}
@@ -378,7 +380,7 @@ func (state *connState) openConnection(ctx context.Context) error {
 		if err = pk.UnmarshalBinary(b[1:n]); err != nil {
 			return fmt.Errorf("read open connection reply 2: %v", err)
 		}
-		state.mtu = pk.MTUSize
+		state.mtu = pk.MTU
 		return nil
 	}
 }
@@ -400,19 +402,19 @@ func (state *connState) request2(ctx context.Context, mtu uint16) {
 // openConnectionRequest1 sends an open connection request 1 packet to the
 // server. If not successful, an error is returned.
 func (state *connState) openConnectionRequest1(mtu uint16) {
-	data, _ := (&message.OpenConnectionRequest1{Protocol: protocolVersion, MaximumSizeNotDropped: mtu}).MarshalBinary()
+	data, _ := (&message.OpenConnectionRequest1{ClientProtocol: protocolVersion, MTU: mtu}).MarshalBinary()
 	_, _ = state.conn.Write(data)
 }
 
 // openConnectionRequest2 sends an open connection request 2 packet to the
 // server. If not successful, an error is returned.
 func (state *connState) openConnectionRequest2(mtu uint16) {
 	data, _ := (&message.OpenConnectionRequest2{
-		ServerAddress:          resolve(state.raddr),
-		ClientPreferredMTUSize: mtu,
-		ClientGUID:             state.id,
-		ServerHasSecurity:      state.serverSecurity,
-		Cookie:                 state.cookie,
+		ServerAddress:     resolve(state.raddr),
+		MTU:               mtu,
+		ClientGUID:        state.id,
+		ServerHasSecurity: state.serverSecurity,
+		Cookie:            state.cookie,
 	}).MarshalBinary()
 	_, _ = state.conn.Write(data)
 }

handler.go

@@ -64,7 +64,7 @@ func (h listenerConnectionHandler) handle(conn *Conn, b []byte) (handled bool, e
 		return true, nil
 	case message.IDDetectLostConnections:
 		// Let the other end know the connection is still alive.
-		return true, conn.send(&message.ConnectedPing{ClientTimestamp: timestamp()})
+		return true, conn.send(&message.ConnectedPing{PingTime: timestamp()})
 	default:
 		return false, nil
 	}
@@ -77,7 +77,7 @@ func (h listenerConnectionHandler) handleUnconnectedPing(b []byte, addr net.Addr
 	if err := pk.UnmarshalBinary(b); err != nil {
 		return fmt.Errorf("read UNCONNECTED_PING: %w", err)
 	}
-	data, _ := (&message.UnconnectedPong{ServerGUID: h.l.id, SendTimestamp: pk.SendTimestamp, Data: *h.l.pongData.Load()}).MarshalBinary()
+	data, _ := (&message.UnconnectedPong{ServerGUID: h.l.id, PingTime: pk.PingTime, Data: *h.l.pongData.Load()}).MarshalBinary()
 	_, err := h.l.conn.WriteTo(data, addr)
 	return err
 }
@@ -89,15 +89,15 @@ func (h listenerConnectionHandler) handleOpenConnectionRequest1(b []byte, addr n
 	if err := pk.UnmarshalBinary(b); err != nil {
 		return fmt.Errorf("read OPEN_CONNECTION_REQUEST_1: %w", err)
 	}
-	mtuSize := min(pk.MaximumSizeNotDropped, maxMTUSize)
+	mtuSize := min(pk.MTU, maxMTUSize)
 
-	if pk.Protocol != protocolVersion {
+	if pk.ClientProtocol != protocolVersion {
 		data, _ := (&message.IncompatibleProtocolVersion{ServerGUID: h.l.id, ServerProtocol: protocolVersion}).MarshalBinary()
 		_, _ = h.l.conn.WriteTo(data, addr)
-		return fmt.Errorf("handle OPEN_CONNECTION_REQUEST_1: incompatible protocol version %v (listener protocol = %v)", pk.Protocol, protocolVersion)
+		return fmt.Errorf("handle OPEN_CONNECTION_REQUEST_1: incompatible protocol version %v (listener protocol = %v)", pk.ClientProtocol, protocolVersion)
 	}
 
-	data, _ := (&message.OpenConnectionReply1{ServerGUID: h.l.id, Secure: false, ServerPreferredMTUSize: mtuSize}).MarshalBinary()
+	data, _ := (&message.OpenConnectionReply1{ServerGUID: h.l.id, ServerHasSecurity: false, MTU: mtuSize}).MarshalBinary()
 	_, err := h.l.conn.WriteTo(data, addr)
 	return err
 }
@@ -109,9 +109,9 @@ func (h listenerConnectionHandler) handleOpenConnectionRequest2(b []byte, addr n
 	if err := pk.UnmarshalBinary(b); err != nil {
 		return fmt.Errorf("read OPEN_CONNECTION_REQUEST_2: %w", err)
 	}
-	mtuSize := min(pk.ClientPreferredMTUSize, maxMTUSize)
+	mtuSize := min(pk.MTU, maxMTUSize)
 
-	data, _ := (&message.OpenConnectionReply2{ServerGUID: h.l.id, ClientAddress: resolve(addr), MTUSize: mtuSize}).MarshalBinary()
+	data, _ := (&message.OpenConnectionReply2{ServerGUID: h.l.id, ClientAddress: resolve(addr), MTU: mtuSize}).MarshalBinary()
 	if _, err := h.l.conn.WriteTo(data, addr); err != nil {
 		return fmt.Errorf("send OPEN_CONNECTION_REPLY_2: %w", err)
 	}
@@ -146,7 +146,7 @@ func (h listenerConnectionHandler) handleConnectionRequest(conn *Conn, b []byte)
 	if err := pk.UnmarshalBinary(b); err != nil {
 		return fmt.Errorf("read CONNECTION_REQUEST: %w", err)
 	}
-	return conn.send(&message.ConnectionRequestAccepted{ClientAddress: resolve(conn.raddr), RequestTimestamp: pk.RequestTimestamp, AcceptedTimestamp: timestamp()})
+	return conn.send(&message.ConnectionRequestAccepted{ClientAddress: resolve(conn.raddr), PingTime: pk.RequestTime, PongTime: timestamp()})
 }
 
 // handleNewIncomingConnection handles an incoming connection packet from the
@@ -194,7 +194,7 @@ func (h dialerConnectionHandler) handle(conn *Conn, b []byte) (handled bool, err
 		return true, nil
 	case message.IDDetectLostConnections:
 		// Let the other end know the connection is still alive.
-		return true, conn.send(&message.ConnectedPing{ClientTimestamp: timestamp()})
+		return true, conn.send(&message.ConnectedPing{PingTime: timestamp()})
 	default:
 		return false, nil
 	}
@@ -212,7 +212,7 @@ func (h dialerConnectionHandler) handleConnectionRequestAccepted(conn *Conn, b [
 		return errUnexpectedAdditionalCRA
 	default:
 		// Make sure to send NewIncomingConnection before closing conn.connected.
-		err := conn.send(&message.NewIncomingConnection{ServerAddress: resolve(conn.raddr), RequestTimestamp: pk.AcceptedTimestamp, AcceptedTimestamp: timestamp()})
+		err := conn.send(&message.NewIncomingConnection{ServerAddress: resolve(conn.raddr), PingTime: pk.PongTime, PongTime: timestamp()})
 		close(conn.connected)
 		return err
 	}
@@ -227,7 +227,7 @@ func handleConnectedPing(conn *Conn, b []byte) error {
 	}
 	// Respond with a connected pong that has the ping timestamp found in the
 	// connected ping, and our own timestamp for the pong timestamp.
-	return conn.send(&message.ConnectedPong{ClientTimestamp: pk.ClientTimestamp, ServerTimestamp: timestamp()})
+	return conn.send(&message.ConnectedPong{PingTime: pk.PingTime, PongTime: timestamp()})
 }
 
 // handleConnectedPong handles a connected pong packet inside of buffer b. An
@@ -237,7 +237,7 @@ func handleConnectedPong(b []byte) error {
 	if err := pk.UnmarshalBinary(b); err != nil {
 		return fmt.Errorf("read CONNECTED_PONG: %w", err)
 	}
-	if pk.ClientTimestamp > timestamp() {
+	if pk.PingTime > timestamp() {
 		return fmt.Errorf("handle CONNECTED_PONG: timestamp is in the future")
 	}
 	// We don't actually use the ConnectedPong to measure rtt. It is too

internal/message/connected_ping.go

@@ -6,20 +6,20 @@ import (
 )
 
 type ConnectedPing struct {
-	ClientTimestamp int64
+	PingTime int64
 }
 
 func (pk *ConnectedPing) UnmarshalBinary(data []byte) error {
 	if len(data) < 8 {
 		return io.ErrUnexpectedEOF
 	}
-	pk.ClientTimestamp = int64(binary.BigEndian.Uint64(data))
+	pk.PingTime = int64(binary.BigEndian.Uint64(data))
 	return nil
 }
 
 func (pk *ConnectedPing) MarshalBinary() (data []byte, err error) {
 	b := make([]byte, 9)
 	b[0] = IDConnectedPing
-	binary.BigEndian.PutUint64(b[1:], uint64(pk.ClientTimestamp))
+	binary.BigEndian.PutUint64(b[1:], uint64(pk.PingTime))
 	return b, nil
 }

internal/message/connected_pong.go

@@ -6,23 +6,23 @@ import (
 )
 
 type ConnectedPong struct {
-	ClientTimestamp int64
-	ServerTimestamp int64
+	PingTime int64
+	PongTime int64
 }
 
 func (pk *ConnectedPong) UnmarshalBinary(data []byte) error {
 	if len(data) < 16 {
 		return io.ErrUnexpectedEOF
 	}
-	pk.ClientTimestamp = int64(binary.BigEndian.Uint64(data))
-	pk.ServerTimestamp = int64(binary.BigEndian.Uint64(data[8:]))
+	pk.PingTime = int64(binary.BigEndian.Uint64(data))
+	pk.PongTime = int64(binary.BigEndian.Uint64(data[8:]))
 	return nil
 }
 
 func (pk *ConnectedPong) MarshalBinary() (data []byte, err error) {
 	b := make([]byte, 17)
 	b[0] = IDConnectedPong
-	binary.BigEndian.PutUint64(b[1:], uint64(pk.ClientTimestamp))
-	binary.BigEndian.PutUint64(b[9:], uint64(pk.ServerTimestamp))
+	binary.BigEndian.PutUint64(b[1:], uint64(pk.PingTime))
+	binary.BigEndian.PutUint64(b[9:], uint64(pk.PongTime))
 	return b, nil
 }

internal/message/connection_request.go

@@ -6,17 +6,18 @@ import (
 )
 
 type ConnectionRequest struct {
-	ClientGUID       int64
-	RequestTimestamp int64
-	Secure           bool
+	ClientGUID int64
+	// RequestTime is a timestamp from the moment the packet is sent.
+	RequestTime int64
+	Secure      bool
 }
 
 func (pk *ConnectionRequest) UnmarshalBinary(data []byte) error {
 	if len(data) < 17 {
 		return io.ErrUnexpectedEOF
 	}
 	pk.ClientGUID = int64(binary.BigEndian.Uint64(data))
-	pk.RequestTimestamp = int64(binary.BigEndian.Uint64(data[8:]))
+	pk.RequestTime = int64(binary.BigEndian.Uint64(data[8:]))
 	pk.Secure = data[16] != 0
 	return nil
 }
@@ -25,7 +26,7 @@ func (pk *ConnectionRequest) MarshalBinary() (data []byte, err error) {
 	b := make([]byte, 18)
 	b[0] = IDConnectionRequest
 	binary.BigEndian.PutUint64(b[1:], uint64(pk.ClientGUID))
-	binary.BigEndian.PutUint64(b[9:], uint64(pk.RequestTimestamp))
+	binary.BigEndian.PutUint64(b[9:], uint64(pk.RequestTime))
 	if pk.Secure {
 		b[17] = 1
 	}

internal/message/connection_request_accepted.go

@@ -7,10 +7,13 @@ import (
 )
 
 type ConnectionRequestAccepted struct {
-	ClientAddress     netip.AddrPort
-	SystemAddresses   systemAddresses
-	RequestTimestamp  int64
-	AcceptedTimestamp int64
+	ClientAddress   netip.AddrPort
+	SystemIndex     uint16
+	SystemAddresses systemAddresses
+	// PingTime is filled out with ConnectionRequest.RequestTime.
+	PingTime int64
+	// PongTime is a timestamp from the moment the packet is sent.
+	PongTime int64
 }
 
 func (pk *ConnectionRequestAccepted) UnmarshalBinary(data []byte) error {
@@ -19,7 +22,8 @@ func (pk *ConnectionRequestAccepted) UnmarshalBinary(data []byte) error {
 	}
 	var offset int
 	pk.ClientAddress, offset = addr(data)
-	offset += 2 // Zero int16.
+	pk.SystemIndex = binary.BigEndian.Uint16(data[offset:])
+	offset += 2
 	for i := range 20 {
 		if len(data) < addrSize(data[offset:]) {
 			return io.ErrUnexpectedEOF
@@ -36,20 +40,21 @@ func (pk *ConnectionRequestAccepted) UnmarshalBinary(data []byte) error {
 	if len(data[offset:]) < 16 {
 		return io.ErrUnexpectedEOF
 	}
-	pk.RequestTimestamp = int64(binary.BigEndian.Uint64(data[offset:]))
-	pk.AcceptedTimestamp = int64(binary.BigEndian.Uint64(data[offset+8:]))
+	pk.PingTime = int64(binary.BigEndian.Uint64(data[offset:]))
+	pk.PongTime = int64(binary.BigEndian.Uint64(data[offset+8:]))
 	return nil
 }
 
 func (pk *ConnectionRequestAccepted) MarshalBinary() (data []byte, err error) {
 	nAddr, nSys := sizeofAddr(pk.ClientAddress), pk.SystemAddresses.sizeOf()
 	b := make([]byte, 1+nAddr+2+nSys+16)
 	b[0] = IDConnectionRequestAccepted
-	offset := 1 + putAddr(b[1:], pk.ClientAddress) + 2 // Zero int16.
+	offset := 1 + putAddr(b[1:], pk.ClientAddress)
+	binary.BigEndian.PutUint16(b[offset:], pk.SystemIndex)
 	for _, addr := range pk.SystemAddresses {
-		offset += putAddr(b[offset:], addr)
+		offset += putAddr(b[offset+2:], addr)
 	}
-	binary.BigEndian.PutUint64(b[offset:], uint64(pk.RequestTimestamp))
-	binary.BigEndian.PutUint64(b[offset+8:], uint64(pk.AcceptedTimestamp))
+	binary.BigEndian.PutUint64(b[offset+2:], uint64(pk.PingTime))
+	binary.BigEndian.PutUint64(b[offset+10:], uint64(pk.PongTime))
 	return b, nil
 }

internal/message/incompatible_protocol_version.go

@@ -6,7 +6,6 @@ import (
 )
 
 type IncompatibleProtocolVersion struct {
-	Magic          [16]byte
 	ServerProtocol byte
 	ServerGUID     int64
 }

internal/message/new_incoming_connection.go

@@ -7,10 +7,12 @@ import (
 )
 
 type NewIncomingConnection struct {
-	ServerAddress     netip.AddrPort
-	SystemAddresses   systemAddresses
-	RequestTimestamp  int64
-	AcceptedTimestamp int64
+	ServerAddress   netip.AddrPort
+	SystemAddresses systemAddresses
+	// PingTime is filled out with ConnectionRequestAccepted.PongTime.
+	PingTime int64
+	// PongTime is a timestamp from the moment the packet is sent.
+	PongTime int64
 }
 
 func (pk *NewIncomingConnection) UnmarshalBinary(data []byte) error {
@@ -35,8 +37,8 @@ func (pk *NewIncomingConnection) UnmarshalBinary(data []byte) error {
 	if len(data[offset:]) < 16 {
 		return io.ErrUnexpectedEOF
 	}
-	pk.RequestTimestamp = int64(binary.BigEndian.Uint64(data[offset:]))
-	pk.AcceptedTimestamp = int64(binary.BigEndian.Uint64(data[offset+8:]))
+	pk.PingTime = int64(binary.BigEndian.Uint64(data[offset:]))
+	pk.PongTime = int64(binary.BigEndian.Uint64(data[offset+8:]))
 	return nil
 }
 
@@ -48,7 +50,7 @@ func (pk *NewIncomingConnection) MarshalBinary() (data []byte, err error) {
 	for _, addr := range pk.SystemAddresses {
 		offset += putAddr(b[offset:], addr)
 	}
-	binary.BigEndian.PutUint64(b[offset:], uint64(pk.RequestTimestamp))
-	binary.BigEndian.PutUint64(b[offset+8:], uint64(pk.AcceptedTimestamp))
+	binary.BigEndian.PutUint64(b[offset:], uint64(pk.PingTime))
+	binary.BigEndian.PutUint64(b[offset+8:], uint64(pk.PongTime))
 	return b, nil
 }