netdev - Re: [PATCH] sit: correct IP protocol used in ipip6

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Date:	Thu, 16 Jun 2016 17:11:17 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	simon.horman@...ronome.com
Cc:	netdev@...r.kernel.org
Subject: Re: [PATCH] sit: correct IP protocol used in ipip6_err

From: Simon Horman <simon.horman@...ronome.com>
Date: Thu, 16 Jun 2016 17:06:19 +0900

> Since 32b8a8e59c9c ("sit: add IPv4 over IPv4 support")
> ipip6_err() may be called for packets whose IP protocol is
> IPPROTO_IPIP as well as those whose IP protocol is IPPROTO_IPV6.
> 
> In the case of IPPROTO_IPIP packets the correct protocol value is not
> passed to ipv4_update_pmtu() or ipv4_redirect().
> 
> This patch resolves this problem by using the IP protocol of the packet
> rather than a hard-coded value. This appears to be consistent
> with the usage of the protocol of a packet by icmp_socket_deliver()
> the caller of ipip6_err().
> 
> I was able to exercise the redirect case by using a setup where an ICMP
> redirect was received for the destination of the encapsulated packet.
> However, it appears that although incorrect the protocol field is not used
> in this case and thus no problem manifests.  On inspection it does not
> appear that a problem will manifest in the fragmentation needed/update pmtu
> case either.
> 
> In short I believe this is a cosmetic fix. None the less, the use of
> IPPROTO_IPV6 seems wrong and confusing.
> 
> Reviewed-by: Dinan Gunawardena <dinan.gunawardena@...ronome.com>
> Signed-off-by: Simon Horman <simon.horman@...ronome.com>

Applied to 'net' and queued up for -stable, thanks Simon.