netdev - Re: [PATCH net-next] net: ipv4: fix multipath RTM

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Date:   Fri, 07 Apr 2017 07:56:40 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     fl@...1.de
Cc:     netdev@...r.kernel.org
Subject: Re: [PATCH net-next] net: ipv4: fix multipath RTM_GETROUTE
 behavior when iif is given

From: Florian Larysch <fl@...1.de>
Date: Fri,  7 Apr 2017 14:42:20 +0200

> inet_rtm_getroute synthesizes a skeletal ICMP skb, which is passed to
> ip_route_input when iif is given. If a multipath route is present for
> the designated destination, fib_multipath_hash ends up being called with
> that skb. However, as that skb contains no information beyond the
> protocol type, the calculated hash does not match the one we would see
> for a real packet.
> 
> There is currently no way to fix this for layer 4 hashing, as
> RTM_GETROUTE doesn't have the necessary information to create layer 4
> headers. To fix this for layer 3 hashing, set appropriate saddr/daddrs
> in the skb and also change the protocol to UDP to avoid special
> treatment for ICMP.
> 
> Signed-off-by: Florian Larysch <fl@...1.de>

Applied, thanks for following up on this.