From: Stephen Hemminger <shemminger@vyatta•com>
To: Ben Hutchings <bhutchings@solarflare•com>
Cc: Herbert Xu <herbert@gondor•apana.org.au>,
netdev <netdev@vger•kernel.org>,
netfilter-devel <netfilter-devel@vger•kernel.org>
Subject: Re: skb_checksum_help() vs GSO
Date: Thu, 12 Jan 2012 14:10:17 -0800 [thread overview]
Message-ID: <20120112141017.0a83e973@nehalam.linuxnetplumber.net> (raw)
In-Reply-To: <1326400930.2740.10.camel@bwh-desktop>
On Thu, 12 Jan 2012 20:42:10 +0000
Ben Hutchings <bhutchings@solarflare•com> wrote:
> skb_checksum_help() does:
>
> if (unlikely(skb_shinfo(skb)->gso_size)) {
> /* Let GSO fix up the checksum. */
> goto out_set_summed;
> }
> ...
> out_set_summed:
> skb->ip_summed = CHECKSUM_NONE;
> out:
> return ret;
>
> but skb_gso_segment() requires that skb->ip_summed == CHECKSUM_PARTIAL
> and WARNs if not. I don't think there's any case where it's valid to
> call both. Shouldn't skb_checksum_help() also WARN and return an error
> code instead of muddling on?
>
> Inspecting the callers of skb_checksum_help(), it looks like sch_netem's
> 'corrupt' option and xt_CHECKSUM might trigger this case.
>
> Ben.
Netem needs to check for GSO manually segment before calling skb_checksum_help.
I'll sort it out.
prev parent reply other threads:[~2012-01-12 22:10 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-12 20:42 skb_checksum_help() vs GSO Ben Hutchings
2012-01-12 22:03 ` Herbert Xu
2012-01-13 0:57 ` [RFC] netem: de-GSO packets before enqueing Stephen Hemminger
2012-01-13 15:54 ` Eric Dumazet
2012-01-13 19:20 ` Stephen Hemminger
2012-01-13 23:44 ` Eric Dumazet
2012-01-14 16:06 ` Hagen Paul Pfeifer
2012-01-12 22:10 ` Stephen Hemminger [this message]
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