Subject: Re: [PATCH v2 0/2] ipv4: Make neigh lookup keys for loopback/point-to-point devices be INADDR_ANY

From: Jim Westfall <[email-masked]>
Date: Mon, 15 Jan 2018 13:42:38 -0800

David Miller <[email-masked]> wrote [01.15.18]:
> From: Jim Westfall <[email-masked]>
> Date: Sun, 14 Jan 2018 04:18:49 -0800
> 
> > This used to be the previous behavior in older kernels but became broken in
> > a263b3093641f (ipv4: Make neigh lookups directly in output packet path)
> > and then later removed because it was broken in 0bb4087cbec0 (ipv4: Fix neigh
> > lookup keying over loopback/point-to-point devices)
> > 
> > Not having this results in there being an arp entry for every remote ip
> > address that the device talks to.  Given a fairly active device it can
> > cause the arp table to become huge and/or having to add/purge large number
> > of entires to keep within table size thresholds.
> ...
> > v2: 
> >  - fixes coding style issues
> 
> Series applied and queued up for -stable, thank you.

Thanks for applying these.  We see the same type of behavior with ipv6  
over point-to-point interfaces and I would like to fix these as well by 
mapping all the ndisc_cache entries to in6addr_any.  However my knowledge 
of ndisc is limited and I'm unclear if its safe to assume ndisc, like 
arp, would never exist on the point-to-point interface.

Thanks
jim