From: Stephen Hemminger <shemminger@vyatta•com>
To: Ben Greear <greearb@candelatech•com>
Cc: Kristian Evensen <kristian.evensen@gmail•com>, netdev@vger•kernel.org
Subject: Re: RTM_NEWLINK not received by application when connecting multiple devices simultaneously
Date: Thu, 19 Apr 2012 07:54:52 -0700 [thread overview]
Message-ID: <20120419075452.379f711b@s6510.linuxnetplumber.net> (raw)
In-Reply-To: <4F90208E.6070201@candelatech.com>
On Thu, 19 Apr 2012 07:26:22 -0700
Ben Greear <greearb@candelatech•com> wrote:
> 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?
I recommend using the libmnl library instead of the older
libnetlink. The code is cleaner and it handles error cases better.
In libmnl there is a callback interface for parsing
netlink messages.
next prev parent reply other threads:[~2012-04-19 14:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-19 11:44 RTM_NEWLINK not received by application when connecting multiple devices simultaneously Kristian Evensen
2012-04-19 14:26 ` Ben Greear
2012-04-19 14:54 ` Stephen Hemminger [this message]
2012-04-19 15:07 ` Kristian Evensen
2012-04-19 19:54 ` Kristian Evensen
2012-04-19 20:36 ` Stephen Hemminger
2012-04-20 14:07 ` Kristian Evensen
2012-04-20 15:14 ` Stephen Hemminger
2012-04-20 15:54 ` Kristian Evensen
2012-04-20 16:04 ` Kristian Evensen
2012-04-20 16:15 ` Stephen Hemminger
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