549 lines
11 KiB
Go
549 lines
11 KiB
Go
package tunnel
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import (
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"context"
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"encoding/binary"
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"fmt"
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"io"
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"log"
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"net"
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"sync"
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"time"
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)
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const (
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// 协议版本
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ProtocolVersion = 0x01
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// 消息头大小
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HeaderSize = 6 // 版本(1) + 类型(1) + 长度(4)
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// 最大包大小
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MaxPacketSize = 1024 * 1024
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// 重连延迟
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ReconnectDelay = 5 * time.Second
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// 消息类型
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MsgTypeConnectRequest = 0x01 // 连接请求
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MsgTypeConnectResponse = 0x02 // 连接响应
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MsgTypeData = 0x03 // 数据传输
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MsgTypeClose = 0x04 // 关闭连接
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MsgTypeKeepAlive = 0x05 // 心跳
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// 连接响应状态
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ConnStatusSuccess = 0x00 // 连接成功
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ConnStatusFailed = 0x01 // 连接失败
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// 超时设置
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ConnectTimeout = 10 * time.Second // 连接超时
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ReadTimeout = 30 * time.Second // 读取超时
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KeepAliveInterval = 15 * time.Second // 心跳间隔
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)
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// TunnelMessage 隧道消息
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type TunnelMessage struct {
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Version byte
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Type byte
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Length uint32
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Data []byte
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}
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// LocalConnection 本地连接
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type LocalConnection struct {
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ID uint32
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TargetAddr string
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Conn net.Conn
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closeChan chan struct{}
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closeOnce sync.Once
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}
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// Client 内网穿透客户端
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type Client struct {
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serverAddr string
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serverConn net.Conn
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cancel context.CancelFunc
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ctx context.Context
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wg sync.WaitGroup
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mu sync.RWMutex
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// 连接管理
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connections map[uint32]*LocalConnection
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connMu sync.RWMutex
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// 消息队列
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sendChan chan *TunnelMessage
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}
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// NewClient 创建新的隧道客户端
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func NewClient(serverAddr string) *Client {
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ctx, cancel := context.WithCancel(context.Background())
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return &Client{
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serverAddr: serverAddr,
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cancel: cancel,
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ctx: ctx,
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connections: make(map[uint32]*LocalConnection),
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sendChan: make(chan *TunnelMessage, 1000),
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}
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}
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// Start 启动隧道客户端
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func (c *Client) Start() error {
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log.Printf("正在连接到隧道服务器: %s", c.serverAddr)
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c.wg.Add(1)
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go c.connectLoop()
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return nil
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}
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// connectLoop 连接循环（支持自动重连）
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func (c *Client) connectLoop() {
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defer c.wg.Done()
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for {
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select {
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case <-c.ctx.Done():
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return
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default:
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}
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conn, err := net.DialTimeout("tcp", c.serverAddr, 10*time.Second)
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if err != nil {
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log.Printf("连接隧道服务器失败: %v，%v 后重试", err, ReconnectDelay)
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time.Sleep(ReconnectDelay)
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continue
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}
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log.Printf("已连接到隧道服务器: %s", c.serverAddr)
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c.mu.Lock()
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c.serverConn = conn
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c.mu.Unlock()
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// 处理连接
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var connWg sync.WaitGroup
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connWg.Add(3)
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go func() {
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defer connWg.Done()
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c.handleServerRead(conn)
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}()
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go func() {
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defer connWg.Done()
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c.handleServerWrite(conn)
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}()
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go func() {
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defer connWg.Done()
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c.keepAliveLoop(conn)
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}()
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// 等待连接断开
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connWg.Wait()
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c.mu.Lock()
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c.serverConn = nil
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c.mu.Unlock()
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// 关闭所有本地连接
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c.connMu.Lock()
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for _, conn := range c.connections {
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conn.closeOnce.Do(func() {
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close(conn.closeChan)
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})
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if conn.Conn != nil {
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conn.Conn.Close()
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}
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}
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c.connections = make(map[uint32]*LocalConnection)
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c.connMu.Unlock()
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log.Printf("与服务器断开连接，%v 后重连", ReconnectDelay)
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time.Sleep(ReconnectDelay)
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}
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}
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// handleServerRead 处理服务器读取
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func (c *Client) handleServerRead(conn net.Conn) {
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defer conn.Close()
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for {
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select {
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case <-c.ctx.Done():
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return
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default:
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}
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msg, err := c.readTunnelMessage(conn)
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if err != nil {
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if err != io.EOF {
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log.Printf("读取隧道消息失败: %v", err)
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}
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return
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}
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c.handleTunnelMessage(msg)
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}
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}
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// handleServerWrite 处理服务器写入
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func (c *Client) handleServerWrite(conn net.Conn) {
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for {
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select {
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case <-c.ctx.Done():
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return
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case msg := <-c.sendChan:
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if err := c.writeTunnelMessage(conn, msg); err != nil {
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log.Printf("写入隧道消息失败: %v", err)
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return
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}
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}
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}
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}
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// readTunnelMessage 读取隧道消息
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func (c *Client) readTunnelMessage(conn net.Conn) (*TunnelMessage, error) {
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// 读取消息头
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header := make([]byte, HeaderSize)
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if _, err := io.ReadFull(conn, header); err != nil {
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return nil, err
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}
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version := header[0]
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msgType := header[1]
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dataLen := binary.BigEndian.Uint32(header[2:6])
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if version != ProtocolVersion {
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return nil, fmt.Errorf("不支持的协议版本: %d", version)
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}
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if dataLen > MaxPacketSize {
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return nil, fmt.Errorf("数据包过大: %d bytes", dataLen)
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}
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// 读取数据
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var data []byte
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if dataLen > 0 {
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data = make([]byte, dataLen)
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if _, err := io.ReadFull(conn, data); err != nil {
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return nil, err
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}
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}
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return &TunnelMessage{
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Version: version,
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Type: msgType,
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Length: dataLen,
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Data: data,
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}, nil
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}
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// writeTunnelMessage 写入隧道消息
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func (c *Client) writeTunnelMessage(conn net.Conn, msg *TunnelMessage) error {
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// 构建消息头
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header := make([]byte, HeaderSize)
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header[0] = msg.Version
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header[1] = msg.Type
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binary.BigEndian.PutUint32(header[2:6], msg.Length)
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// 写入消息头
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if _, err := conn.Write(header); err != nil {
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return err
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}
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// 写入数据
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if msg.Length > 0 && msg.Data != nil {
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if _, err := conn.Write(msg.Data); err != nil {
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return err
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}
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}
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return nil
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}
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// handleTunnelMessage 处理隧道消息
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func (c *Client) handleTunnelMessage(msg *TunnelMessage) {
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switch msg.Type {
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case MsgTypeConnectRequest:
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c.handleConnectRequest(msg)
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case MsgTypeData:
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c.handleDataMessage(msg)
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case MsgTypeClose:
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c.handleCloseMessage(msg)
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case MsgTypeKeepAlive:
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c.handleKeepAlive(msg)
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default:
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log.Printf("未知消息类型: %d", msg.Type)
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}
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}
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// handleConnectRequest 处理连接请求
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func (c *Client) handleConnectRequest(msg *TunnelMessage) {
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// 解析: connID(4) + targetPort(2) + targetIPLen(1) + targetIP(变长)
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if len(msg.Data) < 7 {
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log.Printf("连接请求数据太短")
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return
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}
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connID := binary.BigEndian.Uint32(msg.Data[0:4])
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targetPort := binary.BigEndian.Uint16(msg.Data[4:6])
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targetIPLen := int(msg.Data[6])
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if len(msg.Data) < 7+targetIPLen {
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log.Printf("连接请求数据不完整")
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return
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}
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targetIP := string(msg.Data[7 : 7+targetIPLen])
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targetAddr := net.JoinHostPort(targetIP, fmt.Sprintf("%d", targetPort))
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log.Printf("收到连接请求: ID=%d, 地址=%s", connID, targetAddr)
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// 尝试连接到目标服务
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localConn, err := net.DialTimeout("tcp", targetAddr, ConnectTimeout)
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if err != nil {
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log.Printf("连接目标服务失败 (ID=%d -> %s): %v", connID, targetAddr, err)
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c.sendConnectResponse(connID, ConnStatusFailed)
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return
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}
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// 创建本地连接对象
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connection := &LocalConnection{
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ID: connID,
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TargetAddr: targetAddr,
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Conn: localConn,
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closeChan: make(chan struct{}),
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}
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c.connMu.Lock()
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c.connections[connID] = connection
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c.connMu.Unlock()
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log.Printf("建立目标连接: ID=%d -> %s", connID, targetAddr)
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// 发送连接成功响应
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c.sendConnectResponse(connID, ConnStatusSuccess)
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// 启动数据转发
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go c.forwardData(connection)
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}
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// handleDataMessage 处理数据消息
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func (c *Client) handleDataMessage(msg *TunnelMessage) {
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if len(msg.Data) < 4 {
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log.Printf("数据消息太短")
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return
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}
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connID := binary.BigEndian.Uint32(msg.Data[0:4])
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data := msg.Data[4:]
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c.connMu.RLock()
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connection, exists := c.connections[connID]
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c.connMu.RUnlock()
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if !exists {
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log.Printf("收到未知连接的数据: %d", connID)
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return
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}
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if _, err := connection.Conn.Write(data); err != nil {
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log.Printf("写入目标连接失败 (ID=%d): %v", connID, err)
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c.closeConnection(connID)
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}
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}
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// handleCloseMessage 处理关闭消息
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func (c *Client) handleCloseMessage(msg *TunnelMessage) {
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if len(msg.Data) < 4 {
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log.Printf("关闭消息数据太短")
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return
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}
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connID := binary.BigEndian.Uint32(msg.Data[0:4])
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c.closeConnection(connID)
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}
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// handleKeepAlive 处理心跳消息
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func (c *Client) handleKeepAlive(msg *TunnelMessage) {
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// 回应心跳
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response := &TunnelMessage{
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Version: ProtocolVersion,
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Type: MsgTypeKeepAlive,
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Length: 0,
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Data: nil,
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}
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select {
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case c.sendChan <- response:
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default:
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log.Printf("发送心跳响应失败: 发送队列已满")
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}
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}
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// sendConnectResponse 发送连接响应
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func (c *Client) sendConnectResponse(connID uint32, status byte) {
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responseData := make([]byte, 5)
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binary.BigEndian.PutUint32(responseData[0:4], connID)
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responseData[4] = status
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msg := &TunnelMessage{
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Version: ProtocolVersion,
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Type: MsgTypeConnectResponse,
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Length: 5,
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Data: responseData,
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}
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select {
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case c.sendChan <- msg:
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default:
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log.Printf("发送连接响应失败: 发送队列已满")
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}
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}
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// forwardData 转发数据
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func (c *Client) forwardData(connection *LocalConnection) {
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defer c.closeConnection(connection.ID)
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buffer := make([]byte, 32*1024)
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for {
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select {
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case <-connection.closeChan:
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return
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case <-c.ctx.Done():
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return
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default:
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}
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connection.Conn.SetReadDeadline(time.Now().Add(ReadTimeout))
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n, err := connection.Conn.Read(buffer)
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if err != nil {
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if err != io.EOF && !isTimeout(err) {
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log.Printf("读取目标连接失败 (ID=%d): %v", connection.ID, err)
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}
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return
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}
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// 发送数据到隧道
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dataMsg := make([]byte, 4+n)
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binary.BigEndian.PutUint32(dataMsg[0:4], connection.ID)
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copy(dataMsg[4:], buffer[:n])
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msg := &TunnelMessage{
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Version: ProtocolVersion,
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Type: MsgTypeData,
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Length: uint32(len(dataMsg)),
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Data: dataMsg,
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}
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select {
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case c.sendChan <- msg:
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case <-time.After(5 * time.Second):
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log.Printf("发送数据超时 (ID=%d)", connection.ID)
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return
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case <-c.ctx.Done():
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return
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}
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}
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}
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// closeConnection 关闭连接
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func (c *Client) closeConnection(connID uint32) {
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c.connMu.Lock()
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connection, exists := c.connections[connID]
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if exists {
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delete(c.connections, connID)
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connection.closeOnce.Do(func() {
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close(connection.closeChan)
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})
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connection.Conn.Close()
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}
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c.connMu.Unlock()
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// 发送关闭消息
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closeData := make([]byte, 4)
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binary.BigEndian.PutUint32(closeData, connID)
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msg := &TunnelMessage{
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Version: ProtocolVersion,
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Type: MsgTypeClose,
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Length: 4,
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Data: closeData,
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}
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select {
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case c.sendChan <- msg:
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default:
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// 发送队列满，忽略
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}
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if exists {
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log.Printf("连接已关闭: ID=%d", connID)
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}
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}
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// Stop 停止隧道客户端
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func (c *Client) Stop() error {
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log.Println("正在停止隧道客户端...")
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c.cancel()
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c.mu.Lock()
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if c.serverConn != nil {
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c.serverConn.Close()
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}
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c.mu.Unlock()
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// 等待所有协程结束
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done := make(chan struct{})
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go func() {
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c.wg.Wait()
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close(done)
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}()
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select {
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case <-done:
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log.Println("隧道客户端已停止")
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case <-time.After(5 * time.Second):
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log.Println("隧道客户端停止超时")
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}
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return nil
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}
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// isTimeout 检查是否为超时错误
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func isTimeout(err error) bool {
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if netErr, ok := err.(net.Error); ok {
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return netErr.Timeout()
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}
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return false
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}
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// keepAliveLoop 心跳循环
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func (c *Client) keepAliveLoop(conn net.Conn) {
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ticker := time.NewTicker(KeepAliveInterval)
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defer ticker.Stop()
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for {
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select {
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case <-c.ctx.Done():
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return
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case <-ticker.C:
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// 发送心跳消息
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keepAliveMsg := &TunnelMessage{
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Version: ProtocolVersion,
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Type: MsgTypeKeepAlive,
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Length: 0,
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Data: nil,
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}
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select {
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case c.sendChan <- keepAliveMsg:
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log.Printf("发送心跳消息")
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case <-time.After(5 * time.Second):
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log.Printf("发送心跳消息超时")
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return
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case <-c.ctx.Done():
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return
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}
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}
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}
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} |