frpc: support nathole discover (#3381)

pkg/nathole/utils.go

@@ -0,0 +1,48 @@
+// Copyright 2023 The frp Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package nathole
+
+import (
+	"bytes"
+
+	"github.com/fatedier/golib/crypto"
+
+	"github.com/fatedier/frp/pkg/msg"
+)
+
+func EncodeMessage(m msg.Message, key []byte) ([]byte, error) {
+	buffer := bytes.NewBuffer(nil)
+	if err := msg.WriteMsg(buffer, m); err != nil {
+		return nil, err
+	}
+
+	buf, err := crypto.Encode(buffer.Bytes(), key)
+	if err != nil {
+		return nil, err
+	}
+	return buf, nil
+}
+
+func DecodeMessageInto(data, key []byte, m msg.Message) error {
+	buf, err := crypto.Decode(data, key)
+	if err != nil {
+		return err
+	}
+
+	if err := msg.ReadMsgInto(bytes.NewReader(buf), m); err != nil {
+		return err
+	}
+	return nil
+}