srt_connect behaviour on non-blocking mode

[guilletrejo]

Hi. So I want to setup a caller socket with an "async" connect so it never blocks. I replace the thread block with an "interruptible sleep" that I do with a condition variable. So my code looks something like this:

    srtSock = srt_create_socket();
    const bool connBlock = false;
    srt_setsockflag(srtSock, SRTO_RCVSYN, &connBlock, sizeof(connBlock))
    const int32_t timeout = 5000;
    srt_setsockflag(srtSock, SRTO_CONNTIMEO, &timeout, sizeof(timeout))

    auto ret = srt_connect(srtSock, dstAddr, dstAddrSize);
    while() {
        interruptibleSleep(std::chrono::milliseconds(1000));
        int32_t connectedState;
        int ssize = sizeof(connectedState);
        srt_getsockflag(srtSock, SRTO_EVENT, &connectedState, &ssize);
        if (connectedState == SRT_EPOLL_CONNECT) {
            break;
        }
    }
    ... rest of the program with the connection established

I would hope that if no client is listening on dstAddr, this code will loop forever waiting for the EPOLL_CONNECT event. However, via debug logs I am seeing that it actually only tries to connect for 5 seconds (the SRTO_CONNTIMEO that I set) and then the socket goes to a SRTS_BROKEN state. Is this the expected behaviour? My only workaround is to create the socket again when SRTO_CONNTIMEO has passed and there was no connection.

Is this how is is supposed to be used? It would be very great to be able to have an "infinite" timeout so I know the socket won't be created again and again if the program is running a lot of time with no clients.

Thanks!

[ethouris]

Broken sockets cannot be reused and there's no intended "infinite" value for SRTO_CONNTIMEO. So yes, the only solution is to recreate the socket on failure.

Not sure why you need non-blocking mode for such a scenario. You are doing the same thing as it would be with blocking mode, just with more idle calls.

[guilletrejo]

Thanks a lot for the answer! Actually I need this only because the interruptible sleep. I want to be able to call a stop() function from outside this thread so it stops immediately. In blocking mode, when the thread blocks on srt_connect there's no way to wake it before the timeout.