[PATCH net] openvswitch: update checksum in {push,pop}_mpls

[PATCH net] openvswitch: update checksum in {push,pop}_mpls

[Simon Horman]

In the case of CHECKSUM_COMPLETE the skb checksum should be updated in
{push,pop}_mpls() as they the type in the ethernet header.

As suggested by Pravin Shelar.

Cc: Pravin Shelar <pshelar@nicira.com>
Fixes: 25cd9ba0abc0 ("openvswitch: Add basic MPLS support to kernel")
Signed-off-by: Simon Horman <simon.horman@netronome.com>
---
 net/openvswitch/actions.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index 879185fe183f..d6010b44d423 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -161,6 +161,12 @@ static int push_mpls(struct sk_buff *skb, struct sw_flow_key *key,
 	skb_postpush_rcsum(skb, new_mpls_lse, MPLS_HLEN);
 
 	hdr = eth_hdr(skb);
+	if (skb->ip_summed == CHECKSUM_COMPLETE) {
+		__be16 diff[] = { ~(hdr->h_proto), mpls->mpls_ethertype };
+
+		skb->csum = ~csum_partial((char *)diff, sizeof(diff),
+					~skb->csum);
+	}
 	hdr->h_proto = mpls->mpls_ethertype;
 
 	if (!skb->inner_protocol)
@@ -193,6 +199,12 @@ static int pop_mpls(struct sk_buff *skb, struct sw_flow_key *key,
 	 * field correctly in the presence of VLAN tags.
 	 */
 	hdr = (struct ethhdr *)(skb_mpls_header(skb) - ETH_HLEN);
+	if (skb->ip_summed == CHECKSUM_COMPLETE) {
+		__be16 diff[] = { ~(hdr->h_proto), ethertype };
+
+		skb->csum = ~csum_partial((char *)diff, sizeof(diff),
+					~skb->csum);
+	}
 	hdr->h_proto = ethertype;
 	if (eth_p_mpls(skb->protocol))
 		skb->protocol = ethertype;
-- 
2.1.4

Re: [PATCH net] openvswitch: update checksum in {push,pop}_mpls

[pravin shelar]

On Thu, May 26, 2016 at 11:58 PM, Simon Horman
<simon.horman@netronome.com> wrote:
> In the case of CHECKSUM_COMPLETE the skb checksum should be updated in
> {push,pop}_mpls() as they the type in the ethernet header.
>
> As suggested by Pravin Shelar.
>
> Cc: Pravin Shelar <pshelar@nicira.com>
> Fixes: 25cd9ba0abc0 ("openvswitch: Add basic MPLS support to kernel")
> Signed-off-by: Simon Horman <simon.horman@netronome.com>
> ---
>  net/openvswitch/actions.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
> index 879185fe183f..d6010b44d423 100644
> --- a/net/openvswitch/actions.c
> +++ b/net/openvswitch/actions.c
> @@ -161,6 +161,12 @@ static int push_mpls(struct sk_buff *skb, struct sw_flow_key *key,
>         skb_postpush_rcsum(skb, new_mpls_lse, MPLS_HLEN);
>
>         hdr = eth_hdr(skb);
> +       if (skb->ip_summed == CHECKSUM_COMPLETE) {
> +               __be16 diff[] = { ~(hdr->h_proto), mpls->mpls_ethertype };
> +
> +               skb->csum = ~csum_partial((char *)diff, sizeof(diff),
> +                                       ~skb->csum);
> +       }
>         hdr->h_proto = mpls->mpls_ethertype;
>
This looks correct. But same code is now replicated three times in
this file. can you add helper function to update checksum for such
case?

>         if (!skb->inner_protocol)
> @@ -193,6 +199,12 @@ static int pop_mpls(struct sk_buff *skb, struct sw_flow_key *key,
>          * field correctly in the presence of VLAN tags.
>          */
>         hdr = (struct ethhdr *)(skb_mpls_header(skb) - ETH_HLEN);
> +       if (skb->ip_summed == CHECKSUM_COMPLETE) {
> +               __be16 diff[] = { ~(hdr->h_proto), ethertype };
> +
> +               skb->csum = ~csum_partial((char *)diff, sizeof(diff),
> +                                       ~skb->csum);
> +       }
>         hdr->h_proto = ethertype;
>         if (eth_p_mpls(skb->protocol))
>                 skb->protocol = ethertype;
> --
> 2.1.4
>