新增dnst隧道

internal/util/dns/conn_test.go

@@ -59,3 +59,51 @@ func TestPacketConnRoundTrip(t *testing.T) {
 		t.Fatalf("client ReadFrom got %q, want %q", got, responsePayload)
 	}
 }
+
+func TestPacketConnSetBuffer(t *testing.T) {
+	base := &bufferPacketConn{}
+
+	client := ClientConn(base)
+	if err := client.(setBuffer).SetReadBuffer(1024); err != nil {
+		t.Fatal(err)
+	}
+	if err := client.(setBuffer).SetWriteBuffer(2048); err != nil {
+		t.Fatal(err)
+	}
+	if base.readBuffer != 1024 {
+		t.Fatalf("read buffer = %d, want 1024", base.readBuffer)
+	}
+	if base.writeBuffer != 2048 {
+		t.Fatalf("write buffer = %d, want 2048", base.writeBuffer)
+	}
+
+	server := ServerConn(base)
+	if err := server.(setBuffer).SetReadBuffer(4096); err != nil {
+		t.Fatal(err)
+	}
+	if err := server.(setBuffer).SetWriteBuffer(8192); err != nil {
+		t.Fatal(err)
+	}
+	if base.readBuffer != 4096 {
+		t.Fatalf("read buffer = %d, want 4096", base.readBuffer)
+	}
+	if base.writeBuffer != 8192 {
+		t.Fatalf("write buffer = %d, want 8192", base.writeBuffer)
+	}
+}
+
+type bufferPacketConn struct {
+	net.PacketConn
+	readBuffer  int
+	writeBuffer int
+}
+
+func (c *bufferPacketConn) SetReadBuffer(n int) error {
+	c.readBuffer = n
+	return nil
+}
+
+func (c *bufferPacketConn) SetWriteBuffer(n int) error {
+	c.writeBuffer = n
+	return nil
+}