内网穿透你真的了解吗？

服务端设置(frps.ini)：[common]bind_port = 7000       //此处填写客户端监听的服务端端口号vhost_http_port = 8080 //此处填写用户访问的端口号​客户端配置(frpc.ini)：[common]server_addr = x.x.x.x //此处填写服务端 IP 地址server_port = 7000    //此处填写服务端配置的bind_port​[web]type = http         //此处规定转发请求的协议类型local_port = 80     //此处规定本地服务启动的地址custom_domains = www.example.com   //此处可以填写自定义域名（需要在 IP 地址下配置域名解析）

func runServer(cfg config.ServerCommonConf) (err error) {  log.InitLog(cfg.LogWay, cfg.LogFile, cfg.LogLevel, cfg.LogMaxDays, cfg.DisableLogColor)​  if cfgFile != "" {    log.Info("frps uses config file: %s", cfgFile)  } else {    log.Info("frps uses command line arguments for config")  }    // !important 核心代码1  svr, err := server.NewService(cfg)  if err != nil {    return err  }  log.Info("frps started successfully")  // !important 核心代码2  svr.Run()  return}

for{      // !important 核心代码3conn, session, err := svr.login()    if err != nil {      xl.Warn("login to server failed: %v", err)​      // if login_fail_exit is true, just exit this program      // otherwise sleep a while and try again to connect to server      if svr.cfg.LoginFailExit {        return err      }      util.RandomSleep(10*time.Second, 0.9, 1.1)    } else {      // login success      // !important 核心代码4      ctl := NewControl(svr.ctx, svr.runID, conn, session, svr.cfg, svr.pxyCfgs, svr.visitorCfgs, svr.serverUDPPort, svr.authSetter)      ctl.Run()      svr.ctlMu.Lock()      svr.ctl = ctl      svr.ctlMu.Unlock()      break    }}

func (pxy *BaseProxy) GetWorkConnFromPool(src, dst net.Addr) (workConn net.Conn, err error) {  xl := xlog.FromContextSafe(pxy.ctx)  // try all connections from the pool  for i := 0; i < pxy.poolCount+1; i++ {    // !important 核心代码5    if workConn, err = pxy.getWorkConnFn(); err != nil {      xl.Warn("failed to get work connection: %v", err)      return    }    xl.Debug("get a new work connection: [%s]", workConn.RemoteAddr().String())    xl.Spawn().AppendPrefix(pxy.GetName())    workConn = frpNet.NewContextConn(pxy.ctx, workConn)    ......    // !important 核心代码6    err := msg.WriteMsg(workConn, &msg.StartWorkConn{      ProxyName: pxy.GetName(),      SrcAddr:   srcAddr,      SrcPort:   uint16(srcPort),      DstAddr:   dstAddr,      DstPort:   uint16(dstPort),      Error:     "",    })  }}

func (pxy *TCPProxy) InWorkConn(conn net.Conn, m *msg.StartWorkConn) {  // !important 核心代码7  HandleTCPWorkConnection(pxy.ctx, &pxy.cfg.LocalSvrConf, pxy.proxyPlugin, pxy.cfg.GetBaseInfo(), pxy.limiter,    conn, []byte(pxy.clientCfg.Token), m)}

func (ctl *Control) writer() {  xl := ctl.xl  defer func() {    if err := recover(); err != nil {      xl.Error("panic error: %v", err)      xl.Error(string(debug.Stack()))    }  }()​  defer ctl.allShutdown.Start()  defer ctl.writerShutdown.Done()​  encWriter, err := crypto.NewWriter(ctl.conn, []byte(ctl.serverCfg.Token))  if err != nil {    xl.Error("crypto new writer error: %v", err)    ctl.allShutdown.Start()    return  }  for {    m, ok := <-ctl.sendCh    if !ok {      xl.Info("control writer is closing")      return    }    // !important 核心代码8    if err := msg.WriteMsg(encWriter, m); err != nil {      xl.Warn("write message to control connection error: %v", err)      return    }  }}

// !important 核心代码9func (ctl *Control) reader() {  xl := ctl.xl  defer func() {    if err := recover(); err != nil {      xl.Error("panic error: %v", err)      xl.Error(string(debug.Stack()))    }  }()  defer ctl.readerShutdown.Done()  defer close(ctl.closedCh)​  encReader := crypto.NewReader(ctl.conn, []byte(ctl.clientCfg.Token))  for {    m, err := msg.ReadMsg(encReader)    if err != nil {      if err == io.EOF {        xl.Debug("read from control connection EOF")        return      }      xl.Warn("read error: %v", err)      ctl.conn.Close()      return    }    ctl.readCh <- m  }}