Re: [ncat] Listening Unix domain socket and UDP dies on Connect

[Daniel Miller <bonsaiviking () gmail com>]

John,

I'm sorry it has taken so long to get back to you on this.
Unfortunately, I'm not able to reproduce the error. Is it still
affecting you?

On Sun, Sep 21, 2014 at 12:00 PM, John Schwarz <jschwarz () redhat com> wrote:
> Hi guys,
>
> I'm encountering a really weird problem with the latest ncat version
> taken from your SVN sources, and hopefully you guys could help me (or
> otherwise confirm this is a bug?)
>
> I have an haproxy process which is configured to send logs to a specific
> unix domain socket located at some path at the HD. Prior to running the
> haproxy, I start a ncat process like so:
>
> ncat --unixsock <path> --output /tmp/logs --listen --unix -vvv

I'm assuming you meant --udp and not --unix here

> Once haproxy starts and sends the first log message, though, ncat quits
> and the printout in [1] is given. Using GDB, I've tracked the "connect:
> Invalid argument" to a call to Connect in ncat_listen.c:818 (function
> name: ncat_listen_dgram) which produce EINVAL. Furthermore, commenting
> out the Connect call and recompiling produces actual log messages being
> read by the ncat process.
>
> Do you guys have any ideas what am I doing wrong here?
>
> Much appreciated,
>
> [1]: http://pastebin.com/5xwdWZAE
> --
> John Schwarz,
> Software Engineer, Red Hat.


In order to better solve your problem, will you please provide some
information about your platform? I don't see EINVAL as a documented
error from connect in the Linux man pages, but I'd assume you are
running Red Hat. What kernel version are you using? Can you reproduce
the bug using ncat as the client as well, or is the crash specific to
the haproxy connection?

Of note, I am running across a bug where I can't send more than a
couple messages to a listening unixsock+udp ncat before it stops
receiving data. I'll continue to look into it.

Dan
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