func()

in pkg/nathole/nathole.go [105:158]

• 49 lines of code
• 6 McCabe index (conditional complexity)

func (nc *Controller) HandleVisitor(m *msg.NatHoleVisitor, raddr *net.UDPAddr) {
	sid := nc.GenSid()
	session := &Session{
		Sid:         sid,
		VisitorAddr: raddr,
		NotifyCh:    make(chan struct{}),
	}
	nc.mu.Lock()
	clientCfg, ok := nc.clientCfgs[m.ProxyName]
	if !ok {
		nc.mu.Unlock()
		errInfo := fmt.Sprintf("xtcp server for [%s] doesn't exist", m.ProxyName)
		log.Debug(errInfo)
		_, _ = nc.listener.WriteToUDP(nc.GenNatHoleResponse(nil, errInfo), raddr)
		return
	}
	if m.SignKey != util.GetAuthKey(clientCfg.Sk, m.Timestamp) {
		nc.mu.Unlock()
		errInfo := fmt.Sprintf("xtcp connection of [%s] auth failed", m.ProxyName)
		log.Debug(errInfo)
		_, _ = nc.listener.WriteToUDP(nc.GenNatHoleResponse(nil, errInfo), raddr)
		return
	}

	nc.sessions[sid] = session
	nc.mu.Unlock()
	log.Trace("handle visitor message, sid [%s]", sid)

	defer func() {
		nc.mu.Lock()
		delete(nc.sessions, sid)
		nc.mu.Unlock()
	}()

	err := errors.PanicToError(func() {
		clientCfg.SidCh <- &SidRequest{
			Sid:      sid,
			NotifyCh: session.NotifyCh,
		}
	})
	if err != nil {
		return
	}

	// Wait client connections.
	select {
	case <-session.NotifyCh:
		resp := nc.GenNatHoleResponse(session, "")
		log.Trace("send nat hole response to visitor")
		_, _ = nc.listener.WriteToUDP(resp, raddr)
	case <-time.After(time.Duration(NatHoleTimeout) * time.Second):
		return
	}
}