Obfuscator interface in core & relay/proxy CLI support

internal/core/obfs.go

@@ -0,0 +1,56 @@
+package core
+
+import (
+	"net"
+	"time"
+)
+
+type Obfuscator interface {
+	Deobfuscate(buf []byte, n int) int
+	Obfuscate(p []byte) []byte
+}
+
+type obfsPacketConn struct {
+	Orig       net.PacketConn
+	Obfuscator Obfuscator
+}
+
+func (c *obfsPacketConn) ReadFrom(p []byte) (n int, addr net.Addr, err error) {
+	oldN, addr, err := c.Orig.ReadFrom(p)
+	if oldN > 0 {
+		newN := c.Obfuscator.Deobfuscate(p, oldN)
+		return newN, addr, err
+	} else {
+		return 0, addr, err
+	}
+}
+
+func (c *obfsPacketConn) WriteTo(p []byte, addr net.Addr) (n int, err error) {
+	np := c.Obfuscator.Obfuscate(p)
+	_, err = c.Orig.WriteTo(np, addr)
+	if err != nil {
+		return 0, err
+	} else {
+		return len(p), nil
+	}
+}
+
+func (c *obfsPacketConn) Close() error {
+	return c.Orig.Close()
+}
+
+func (c *obfsPacketConn) LocalAddr() net.Addr {
+	return c.Orig.LocalAddr()
+}
+
+func (c *obfsPacketConn) SetDeadline(t time.Time) error {
+	return c.Orig.SetDeadline(t)
+}
+
+func (c *obfsPacketConn) SetReadDeadline(t time.Time) error {
+	return c.Orig.SetReadDeadline(t)
+}
+
+func (c *obfsPacketConn) SetWriteDeadline(t time.Time) error {
+	return c.Orig.SetWriteDeadline(t)
+}