mirror of
https://github.com/fatedier/frp.git
synced 2025-04-28 19:51:27 +00:00
82 lines
2.0 KiB
Go
82 lines
2.0 KiB
Go
// Copyright 2025 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 vnet
|
|
|
|
import (
|
|
"encoding/binary"
|
|
"fmt"
|
|
"io"
|
|
)
|
|
|
|
// Maximum message size
|
|
const (
|
|
maxMessageSize = 1024 * 1024 // 1MB
|
|
)
|
|
|
|
// Format: [length(4 bytes)][data(length bytes)]
|
|
|
|
// ReadMessage reads a framed message from the reader
|
|
func ReadMessage(r io.Reader) ([]byte, error) {
|
|
// Read length (4 bytes)
|
|
var length uint32
|
|
err := binary.Read(r, binary.LittleEndian, &length)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("read message length error: %w", err)
|
|
}
|
|
|
|
// Check length to prevent DoS
|
|
if length == 0 {
|
|
return nil, fmt.Errorf("message length is 0")
|
|
}
|
|
if length > maxMessageSize {
|
|
return nil, fmt.Errorf("message too large: %d > %d", length, maxMessageSize)
|
|
}
|
|
|
|
// Read message data
|
|
data := make([]byte, length)
|
|
_, err = io.ReadFull(r, data)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("read message data error: %w", err)
|
|
}
|
|
|
|
return data, nil
|
|
}
|
|
|
|
// WriteMessage writes a framed message to the writer
|
|
func WriteMessage(w io.Writer, data []byte) error {
|
|
// Get data length
|
|
length := uint32(len(data))
|
|
if length == 0 {
|
|
return fmt.Errorf("message data length is 0")
|
|
}
|
|
if length > maxMessageSize {
|
|
return fmt.Errorf("message too large: %d > %d", length, maxMessageSize)
|
|
}
|
|
|
|
// Write length
|
|
err := binary.Write(w, binary.LittleEndian, length)
|
|
if err != nil {
|
|
return fmt.Errorf("write message length error: %w", err)
|
|
}
|
|
|
|
// Write message data
|
|
_, err = w.Write(data)
|
|
if err != nil {
|
|
return fmt.Errorf("write message data error: %w", err)
|
|
}
|
|
|
|
return nil
|
|
}
|