On Sun, Apr 21, 2024 at 04:22:32PM +0200, Ismael Luceno wrote:
> It was observed in the wild that pairs of consecutive packets would leave
> the IPVS with the same wrong checksum, and the issue only went away when
> disabling GSO.
>
> IPVS needs to avoid computing the SCTP checksum when using GSO.
I am placing this into the nf.git tree for submission upstream in the
next pull request, unless stated otherwise.
Thanks.
> Fixes: 90017accff61 ("sctp: Add GSO support", 2016-06-02)
> Co-developed-by: Firo Yang <firo.yang@xxxxxxxx>
> Signed-off-by: Ismael Luceno <iluceno@xxxxxxx>
> Tested-by: Andreas Taschner <andreas.taschner@xxxxxxxx>
> CC: Michal Kubeček <mkubecek@xxxxxxxx>
> CC: Simon Horman <horms@xxxxxxxxxxxx>
> CC: Julian Anastasov <ja@xxxxxx>
> CC: lvs-devel@xxxxxxxxxxxxxxx
> CC: netfilter-devel@xxxxxxxxxxxxxxx
> CC: netdev@xxxxxxxxxxxxxxx
> CC: coreteam@xxxxxxxxxxxxx
> ---
>
> Notes:
> Changes since v1:
> * Added skb_is_gso before skb_is_gso_sctp.
> * Added "Fixes" tag.
>
> net/netfilter/ipvs/ip_vs_proto_sctp.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/net/netfilter/ipvs/ip_vs_proto_sctp.c b/net/netfilter/ipvs/ip_vs_proto_sctp.c
> index a0921adc31a9..1e689c714127 100644
> --- a/net/netfilter/ipvs/ip_vs_proto_sctp.c
> +++ b/net/netfilter/ipvs/ip_vs_proto_sctp.c
> @@ -126,7 +126,8 @@ sctp_snat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
> if (sctph->source != cp->vport || payload_csum ||
> skb->ip_summed == CHECKSUM_PARTIAL) {
> sctph->source = cp->vport;
> - sctp_nat_csum(skb, sctph, sctphoff);
> + if (!skb_is_gso(skb) || !skb_is_gso_sctp(skb))
> + sctp_nat_csum(skb, sctph, sctphoff);
> } else {
> skb->ip_summed = CHECKSUM_UNNECESSARY;
> }
> @@ -174,7 +175,8 @@ sctp_dnat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
> (skb->ip_summed == CHECKSUM_PARTIAL &&
> !(skb_dst(skb)->dev->features & NETIF_F_SCTP_CRC))) {
> sctph->dest = cp->dport;
> - sctp_nat_csum(skb, sctph, sctphoff);
> + if (!skb_is_gso(skb) || !skb_is_gso_sctp(skb))
> + sctp_nat_csum(skb, sctph, sctphoff);
> } else if (skb->ip_summed != CHECKSUM_PARTIAL) {
> skb->ip_summed = CHECKSUM_UNNECESSARY;
> }
> --
> 2.43.0
>
>
