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Date: Tue, 27 Oct 2015 19:30:43 +0100 From: Hannes Frederic Sowa <hannes@...essinduktion.org> To: Tom Herbert <tom@...bertland.com> Cc: Linux Kernel Network Developers <netdev@...r.kernel.org>, Eric Dumazet <edumazet@...gle.com>, Vladislav Yasevich <vyasevich@...il.com>, Benjamin Coddington <bcodding@...hat.com> Subject: Re: [PATCH net v2 2/4] ipv4: add defensive check for CHECKSUM_PARTIAL skbs in ip_fragment On Tue, Oct 27, 2015, at 17:06, Tom Herbert wrote: > On Tue, Oct 27, 2015 at 8:02 AM, Hannes Frederic Sowa > <hannes@...essinduktion.org> wrote: > > CHECKSUM_PARTIAL skbs should never arrive in ip_fragment. If we get one > > of those warn about them once and handle them gracefully by recalculating > > the checksum. > > > > Cc: Eric Dumazet <edumazet@...gle.com> > > Cc: Vlad Yasevich <vyasevich@...il.com> > > Cc: Benjamin Coddington <bcodding@...hat.com> > > Cc: Tom Herbert <tom@...bertland.com> > > Signed-off-by: Hannes Frederic Sowa <hannes@...essinduktion.org> > > --- > > net/ipv4/ip_output.c | 8 +++++--- > > 1 file changed, 5 insertions(+), 3 deletions(-) > > > > diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c > > index 0b02417..3f94a3b 100644 > > --- a/net/ipv4/ip_output.c > > +++ b/net/ipv4/ip_output.c > > @@ -533,6 +533,11 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, > > > > dev = rt->dst.dev; > > > > + /* for offloaded checksums cleanup checksum before fragmentation */ > > + if (WARN_ON_ONCE(skb->ip_summed == CHECKSUM_PARTIAL) && > > + (err = skb_checksum_help(skb))) > > + goto fail; > > + > Why the WARN_ON_ONCE? Is there a prior check somewhere that avoid this > condition? While I am pretty sure we should not hit the condition in IPv6 anymore, I think this could frighten people in IPv4 land. I will repost without the WARN_ON_ONCE. Maybe it makes sense to use the IFF_DEBUG interface flags again? :) I will repost without those WARN_ON_ONCEs. Bye, Hannes -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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