func()

in server/group/tcp.go [94:140]

• 44 lines of code
• 9 McCabe index (conditional complexity)

func (tg *TCPGroup) Listen(proxyName string, group string, groupKey string, addr string, port int) (ln *TCPGroupListener, realPort int, err error) {
	tg.mu.Lock()
	defer tg.mu.Unlock()
	if len(tg.lns) == 0 {
		// the first listener, listen on the real address
		realPort, err = tg.ctl.portManager.Acquire(proxyName, port)
		if err != nil {
			return
		}
		tcpLn, errRet := net.Listen("tcp", net.JoinHostPort(addr, strconv.Itoa(port)))
		if errRet != nil {
			err = errRet
			return
		}
		ln = newTCPGroupListener(group, tg, tcpLn.Addr())

		tg.group = group
		tg.groupKey = groupKey
		tg.addr = addr
		tg.port = port
		tg.realPort = realPort
		tg.tcpLn = tcpLn
		tg.lns = append(tg.lns, ln)
		if tg.acceptCh == nil {
			tg.acceptCh = make(chan net.Conn)
		}
		go tg.worker()
	} else {
		// address and port in the same group must be equal
		if tg.group != group || tg.addr != addr {
			err = ErrGroupParamsInvalid
			return
		}
		if tg.port != port {
			err = ErrGroupDifferentPort
			return
		}
		if tg.groupKey != groupKey {
			err = ErrGroupAuthFailed
			return
		}
		ln = newTCPGroupListener(group, tg, tg.lns[0].Addr())
		realPort = tg.realPort
		tg.lns = append(tg.lns, ln)
	}
	return
}