Re: [PATCH 0/3] ipv4: pmtu fixes

[David Miller <davem@davemloft.net>]

From: Steffen Klassert <steffen.klassert@secunet.com>
Date: Mon, 8 Oct 2012 10:46:42 +0200

> This patchset fixes some issues that came with the routing cache removal.
> 
> 1) IPsec and others (udp, ipvs) may cache output routes, these routes
> need to be invalidated on pmtu events in the same way e.g. tcp socket
> cached routes are invalidated. With this we always invalidate or update
> (if we already use a nh exeption route) the old route on pmtu events. 
> 
> This has the drawback that we may needlessly invalidate an uncached route,
> but this fixes all the users that cache routes and pmtu events are rare, so
> this should not be a real issue.
> 
> 2) We create nh exeptions if a user (e.g. tracepath) tries to do pmtu
> dicsovery with packets bigger than the output device mtu. The device mtu
> is not learned and does not expire, so don't create an exeption route.
> 
> 3) We report cached pmtu values to userspace even if they are expired.
> Fix this by checking for expiration before we report.

All applied and queued up for -stable, thanks!