mirror of
https://github.com/fatedier/frp.git
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82 lines
2.0 KiB
Go
82 lines
2.0 KiB
Go
// Copyright 2025 The frp Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package vnet
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import (
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"encoding/binary"
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"fmt"
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"io"
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)
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// Maximum message size
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const (
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maxMessageSize = 1024 * 1024 // 1MB
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)
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// Format: [length(4 bytes)][data(length bytes)]
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// ReadMessage reads a framed message from the reader
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func ReadMessage(r io.Reader) ([]byte, error) {
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// Read length (4 bytes)
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var length uint32
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err := binary.Read(r, binary.LittleEndian, &length)
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if err != nil {
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return nil, fmt.Errorf("read message length error: %v", err)
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}
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// Check length to prevent DoS
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if length == 0 {
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return nil, fmt.Errorf("message length is 0")
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}
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if length > maxMessageSize {
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return nil, fmt.Errorf("message too large: %d > %d", length, maxMessageSize)
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}
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// Read message data
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data := make([]byte, length)
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_, err = io.ReadFull(r, data)
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if err != nil {
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return nil, fmt.Errorf("read message data error: %v", err)
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}
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return data, nil
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}
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// WriteMessage writes a framed message to the writer
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func WriteMessage(w io.Writer, data []byte) error {
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// Get data length
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length := uint32(len(data))
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if length == 0 {
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return fmt.Errorf("message data length is 0")
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}
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if length > maxMessageSize {
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return fmt.Errorf("message too large: %d > %d", length, maxMessageSize)
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}
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// Write length
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err := binary.Write(w, binary.LittleEndian, length)
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if err != nil {
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return fmt.Errorf("write message length error: %v", err)
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}
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// Write message data
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_, err = w.Write(data)
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if err != nil {
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return fmt.Errorf("write message data error: %v", err)
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}
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return nil
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}
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