Hi,

I implemented DialTimeout on a TLS connection and trying to define my
source (laddr) address. In previous versions of Go this was possible with
the laddr option in the Dial command, now this option is only available in
DialTCP but that function does not have a timeout option.

Any ideas how I can make a TLS connection from a defined laddr with a
timeout?

    // Configure a timeout of 15 seconds
    ipConn, errDial := net.DialTimeout("tcp", "www.google.com:443",
15*time.Second)
    config := tls.Config{ServerName: "www.google.com"}
    conn := tls.Client(ipConn, &config)
    defer conn.Close()

    // TLS Handshake
    errHandshake := conn.Handshake()

Thanks,

Paul

You can write it by yourself. Here is my code:

func TcpDial(localAddress string, remoteAddress string, timeout
time.Duration) (*net.TCPConn, error) {
    timer := time.NewTimer(timeout)
    defer timer.Stop()

    type Result struct {
        *net.TCPConn
        error
    }
    channel := make(chan *Result, 1)
    go func() {
        var localAddr, remoteAddr *net.TCPAddr
        var err error
        var tcpConn *net.TCPConn

        if localAddress != "" {
            localAddr, err = net.ResolveTCPAddr("tcp", localAddress)
            if err != nil {
                goto finished
            }
        }
        remoteAddr, err = net.ResolveTCPAddr("tcp", remoteAddress)
        if err != nil {
            goto finished
        }
        tcpConn, err = net.DialTCP("tcp", localAddr, remoteAddr)
        if err != nil {
            goto finished
        }
    finished:
        channel <- &Result{TCPConn: tcpConn, error: err}
    }()
    select {
    case <-timer.C:
        return nil, errors.New("connect timeout")
    case result := <-channel:
        if result.error != nil {
            return nil, result.error
        }
        return result.TCPConn, nil
    }
    panic("unreachable")

On Fri, Sep 7, 2012 at 4:39 PM, Paul van Brouwershaven

--
Best regards,
Jingcheng Zhang
Beijing, P.R.China

Thanks, you code looks good, this would be a simple solution.

I see your code looks a like the original DialTimeout where the following
comment is listed:

   121          // TODO(bradfitz): the timeout should be pushed down into the   122             // net package's event loop, so on timeout to dead hosts we   123               // don't have a goroutine sticking around for the default of   124              // ~3 minutes.

So this basically means that the goroutine keeps running and the TCP
session keeps open. Is there a way to kill the goroutine and linked TCP
session?

I found issue 2631 that is mentioning this comment.

It looks like the inefficiency in the handling timeouts is not high on the
priority list (Priority-Later).

http://code.google.com/p/go/issues/detail?id=2631

On Fri, Sep 7, 2012 at 5:08 PM, Paul van Brouwershaven

Yeah, I "steal" the idea from Brad's DialTimeout() implementation :p

I'm worrying about this too. Maybe Brad will have an idea :)

--
Best regards,
Jingcheng Zhang
Beijing, P.R.China

It's not only worrying me. I have crashed several routers because
to-many open sessions.