From mboxrd@z Thu Jan  1 00:00:00 1970
From: Florian Westphal <fw@strlen.de>
Subject: Re: [PATCH 4/5] netfilter: nfnetlink_queue: add skb info attribute
Date: Tue, 16 Apr 2013 19:47:51 +0200
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Cc: Florian Westphal <fw@strlen.de>, netfilter-devel@vger.kernel.org
To: Eric Dumazet <eric.dumazet@gmail.com>
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Eric Dumazet <eric.dumazet@gmail.com> wrote:
> On Tue, 2013-04-16 at 17:32 +0200, Florian Westphal wrote:
> > Once we allow userspace to receive gso/gro packets, userspace
> > needs to be able to determine when checksums appear to be
> > broken, but are not.
> > 
> > NFQA_SKB_CSUMNOTREADY means 'checksums will be fixed in kernel
> > later, pretend they are ok'.
> > 
> > NFQA_SKB_GSO could be used for statistics, or to determine when
> > packet size exceeds mtu.

[..]

> > +static int nfqnl_put_packet_info(struct sk_buff *nlskb, struct sk_buff *packet)
> > +{
> > +	__u32 flags = 0;
> > +
> > +	if (skb_is_gso(packet))
> > +		flags = NFQA_SKB_GSO;
>  
> > +	if (packet->ip_summed == CHECKSUM_PARTIAL)
> > +		flags |= NFQA_SKB_CSUMNOTREADY;
> > +
> > +	return nla_put_be32(nlskb, NFQA_SKB_INFO, htonl(flags));
> 
> Maybe you could avoid sending NFQA_SKB_INFO if flags == 0 ?

Sure, will change it in the next round.