Praveen Chaudhary <praveen5...@gmail.com> wrote:
> Update skb->csum, when netfilter code updates IPV6 SRC\DST address in IPV6
> HEADER due to iptable rule.
>
> Signed-off-by: Praveen Chaudhary <pchaudh...@linkedin.com>
> Signed-off-by: Zhenggen Xu <z...@linkedin.com>
> Signed-off-by: Andy Stracner <astrac...@linkedin.com>
> ---
> include/net/checksum.h | 2 ++
> net/core/utils.c | 13 +++++++++++++
> net/netfilter/nf_nat_proto.c | 2 ++
> 3 files changed, 17 insertions(+)
>
> diff --git a/include/net/checksum.h b/include/net/checksum.h
> index 97bf488..d7d28b7 100644
> --- a/include/net/checksum.h
> +++ b/include/net/checksum.h
> @@ -145,6 +145,8 @@ void inet_proto_csum_replace4(__sum16 *sum, struct
> sk_buff *skb,
> void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
> const __be32 *from, const __be32 *to,
> bool pseudohdr);
> +void inet_proto_skb_csum_replace16(struct sk_buff *skb,
> + const __be32 *from, const __be32 *to);
> void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb,
> __wsum diff, bool pseudohdr);
>
> diff --git a/net/core/utils.c b/net/core/utils.c
> index 6b6e51d..ab3284b 100644
> --- a/net/core/utils.c
> +++ b/net/core/utils.c
> @@ -458,6 +458,19 @@ void inet_proto_csum_replace16(__sum16 *sum, struct
> sk_buff *skb,
> }
> EXPORT_SYMBOL(inet_proto_csum_replace16);
>
> +void inet_proto_skb_csum_replace16(struct sk_buff *skb,
> + const __be32 *from, const __be32 *to)
> +{
> + __be32 diff[] = {
> + ~from[0], ~from[1], ~from[2], ~from[3],
> + to[0], to[1], to[2], to[3],
> + };
> + if (skb->ip_summed == CHECKSUM_COMPLETE)
> + skb->csum = csum_partial(diff, sizeof(diff),
> + skb->csum);
> +}
> +EXPORT_SYMBOL(inet_proto_skb_csum_replace16);
> +
> void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb,
> __wsum diff, bool pseudohdr)
> {
> diff --git a/net/netfilter/nf_nat_proto.c b/net/netfilter/nf_nat_proto.c
> index 0a59c14..de94590 100644
> --- a/net/netfilter/nf_nat_proto.c
> +++ b/net/netfilter/nf_nat_proto.c
> @@ -467,6 +467,8 @@ static void nf_nat_ipv6_csum_update(struct sk_buff *skb,
> }
> inet_proto_csum_replace16(check, skb, oldip->s6_addr32,
> newip->s6_addr32, true);
> + inet_proto_skb_csum_replace16(skb, oldip->s6_addr32,
> + newip->s6_addr32);
This is confusing.
You're saying that inet_proto_csum_replace16() is producing a wrong
skb->csum. So why are you adding a new function to do the
csum calculation instead of fixing inet_proto_csum_replace16() to do
the right thing?
