Subject: Re: [RFC PATCH net-next 3/3] packet: nlmon: virtual netlink monitoring device for packet sockets

From: Stephen Hemminger <[email-masked]>
Date: Thu, 20 Jun 2013 08:46:53 -0700

On Thu, 20 Jun 2013 10:07:10 +0200
Daniel Borkmann <[email-masked]> wrote:

> On 06/19/2013 08:59 PM, Stephen Hemminger wrote:
> > On Wed, 19 Jun 2013 20:04:46 +0200
> > Daniel Borkmann <[email-masked]> wrote:
> >
> >> Currently, there is no good possibility to debug netlink traffic that
> >> is being exchanged between kernel and user space. Therefore, this patch
> >> implements a netlink virtual device, so that netlink messages will be
> >> made visible to PF_PACKET sockets. Once there was an approach with a
> >> similar idea [1], but it got forgotten somehow.
> >
> > ip monitor all
> 
> Well, but this is only restricted to debugging rtnl and there are many other
> subsystems using netlink. Also, it's not about low-level debugging netlink
> in general from what I see from the code. So it's not really the same resp.
> comparable to each other.

I was thinking that having a more general monitor is great, and maybe you
could reuse the similar concepts that already exist. I like the device idea
or maybe teaching libpcap how to handle another input source like Patrick's
mmap netlink would be better.