Subject: Re: RTM_NEWLINK not received by application when connecting multiple devices simultaneously

From: Ben Greear <[email-masked]>
Date: Thu, 19 Apr 2012 07:26:22 -0700

On 04/19/2012 04:44 AM, Kristian Evensen wrote:
> Hello,

> The application works as intended when I connect interfaces one by
> one. However, if I connect two interfaces "simultaneously", the
> RTM_NEWLINK message for one of the interfaces is sometimes not
> received. Nothing arrives at the handle. It seems to be random which
> RTM_NEWLINK actually arrives. I have only been able to recreate this
> problem when connecting two USB 3G modems and automatically dialing
> the ISP, but I assume it would happen with other technologies as well.
> What puzzles me, is that both RTM_NEWLINK messages are seen by for
> example ip monitor. This has led me to conclusion that there is a bug
> in my application, and my question is therefore, are there any common
> mistakes one can make or things to forget that would cause a message
> to get lost or not be received, or does anyone have any tips on where
> I can start looking?

Multiple netlink msgs can be received in each read of a netlink
socket.  Maybe you are only processing the first one?

Thanks,
Ben

-- 
Ben Greear <[email-masked]>
Candela Technologies Inc  http://www.candelatech.com