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

David Miller [off-list ref] wrote [01.15.18]:

From: Jim Westfall <redacted>
Date: Sun, 14 Jan 2018 04:18:49 -0800

quoted

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.

...

quoted

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