Re: [patch nf-next] IPVS: ICMPv6 checksum calculation

From: Simon Horman
Date: Tue Aug 17 2010 - 20:22:04 EST


[ CCing netdev for comment ]

On Tue, Aug 17, 2010 at 12:25:56PM +0300, Julian Anastasov wrote:
>
> Hello,
>
> On Tue, 17 Aug 2010, Simon Horman wrote:
>
> > From: Xiaoyu Du <tingsrain@xxxxxxxxx>
> >
> > Correct the ICMPv6 checksum calculation when IPv6 is is used
> >
> > Signed-off-by: Xiaoyu Du <tingsrain@xxxxxxxxx>
> > Signed-off-by: Simon Horman <horms@xxxxxxxxxxxx>
> >
> > ---
> > net/netfilter/ipvs/ip_vs_core.c | 6 +++++-
> > 1 files changed, 5 insertions(+), 1 deletions(-)
> >
> > I wonder if this is -stable or .35 material.
> >
> > diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c
> > index 4f8ddba..124a1ae 100644
> > --- a/net/netfilter/ipvs/ip_vs_core.c
> > +++ b/net/netfilter/ipvs/ip_vs_core.c
> > @@ -638,8 +638,12 @@ void ip_vs_nat_icmp_v6(struct sk_buff *skb,
> > struct ip_vs_protocol *pp,
> >
> > /* And finally the ICMP checksum */
> > icmph->icmp6_cksum = 0;
> > - /* TODO IPv6: is this correct for ICMPv6? */
>
> May be ip_vs_checksum_complete() is not needed here?
> Also, skb->csum is not valid for every ip_summed value.
> May be we need to apply CHECKSUM_PARTIAL kind of setup for the IPv6.
> Such example is net/ipv6/udp.c:udp6_ufo_send_check().
> Later dev_queue_xmit() and skb_checksum_help() should take care
> for the next steps. Something like this can be tested:
>
> icmph->icmp6_cksum = csum_ipv6_magic(&iph->saddr,
> &iph->daddr,
> skb->len - icmp_offset, IPPROTO_ICMPV6,
> 0);
> skb->csum_start = skb_network_header(skb) - skb->head +
> icmp_offset;
> skb->csum_offset = offsetof(struct icmp6hdr, icmp6_cksum);
> skb->ip_summed = CHECKSUM_PARTIAL;
>
> > ip_vs_checksum_complete(skb, icmp_offset);
> > + icmph->icmp6_cksum = csum_ipv6_magic(&iph->saddr,
> > + &iph->daddr,
> > + skb->len - icmp_offset, IPPROTO_ICMPV6,
> > + skb->csum);
> > +
> > skb->ip_summed = CHECKSUM_UNNECESSARY;
> >
> > if (inout)
>
> Regards
>
> --
> Julian Anastasov <ja@xxxxxx>
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