Proxy: Add Hysteria outbound & transport (version 2, udphop) and Salamander udpmask (#5508)

https://github.com/XTLS/Xray-core/issues/3547#issuecomment-3549896520
https://github.com/XTLS/Xray-core/issues/2635#issuecomment-3570871754

transport/internet/finalmask/finalmask.go

@@ -0,0 +1,127 @@
+package finalmask
+
+import (
+	"net"
+)
+
+type Udpmask interface {
+	UDP()
+
+	WrapConnClient(net.Conn) (net.Conn, error)
+	WrapConnServer(net.Conn) (net.Conn, error)
+
+	WrapPacketConnClient(net.PacketConn) (net.PacketConn, error)
+	WrapPacketConnServer(net.PacketConn) (net.PacketConn, error)
+
+	Size() int
+	Serialize([]byte)
+}
+
+type UdpmaskManager struct {
+	udpmasks []Udpmask
+}
+
+func NewUdpmaskManager(udpmasks []Udpmask) *UdpmaskManager {
+	return &UdpmaskManager{
+		udpmasks: udpmasks,
+	}
+}
+
+func (m *UdpmaskManager) WrapConnClient(raw net.Conn) (net.Conn, error) {
+	var err error
+	for _, mask := range m.udpmasks {
+		raw, err = mask.WrapConnClient(raw)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return raw, nil
+}
+
+func (m *UdpmaskManager) WrapConnServer(raw net.Conn) (net.Conn, error) {
+	var err error
+	for _, mask := range m.udpmasks {
+		raw, err = mask.WrapConnServer(raw)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return raw, nil
+}
+
+func (m *UdpmaskManager) WrapPacketConnClient(raw net.PacketConn) (net.PacketConn, error) {
+	var err error
+	for _, mask := range m.udpmasks {
+		raw, err = mask.WrapPacketConnClient(raw)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return raw, nil
+}
+
+func (m *UdpmaskManager) WrapPacketConnServer(raw net.PacketConn) (net.PacketConn, error) {
+	var err error
+	for _, mask := range m.udpmasks {
+		raw, err = mask.WrapPacketConnServer(raw)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return raw, nil
+}
+
+func (m *UdpmaskManager) Size() int {
+	size := 0
+	for _, mask := range m.udpmasks {
+		size += mask.Size()
+	}
+	return size
+}
+
+func (m *UdpmaskManager) Serialize(b []byte) {
+	index := 0
+	for _, mask := range m.udpmasks {
+		mask.Serialize(b[index:])
+		index += mask.Size()
+	}
+}
+
+type Tcpmask interface {
+	TCP()
+
+	WrapConnClient(net.Conn) (net.Conn, error)
+	WrapConnServer(net.Conn) (net.Conn, error)
+}
+
+type TcpmaskManager struct {
+	tcpmasks []Tcpmask
+}
+
+func NewTcpmaskManager(tcpmasks []Tcpmask) *TcpmaskManager {
+	return &TcpmaskManager{
+		tcpmasks: tcpmasks,
+	}
+}
+
+func (m *TcpmaskManager) WrapConnClient(raw net.Conn) (net.Conn, error) {
+	var err error
+	for _, mask := range m.tcpmasks {
+		raw, err = mask.WrapConnClient(raw)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return raw, nil
+}
+
+func (m *TcpmaskManager) WrapConnServer(raw net.Conn) (net.Conn, error) {
+	var err error
+	for _, mask := range m.tcpmasks {
+		raw, err = mask.WrapConnServer(raw)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return raw, nil
+}