[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [PATCH net] xen-netback: make sure skb linear area covers checksum field



>>> On 11.12.13 at 17:37, Paul Durrant <paul.durrant@xxxxxxxxxx> wrote:
> skb_partial_csum_set requires that the linear area of the skb covers the
> checksum field. The checksum setup code in netback was only doing that
> pullup in the case when the pseudo header checksum was being recalculated
> though. This patch makes that pullup unconditional. (I pullup the whole
> transport header just for simplicity; the requirement is only for the check
> field but in the case of UDP this is the last field in the header and in the
> case of TCP it's the last but one).
> 
> The lack of pullup manifested as failures running Microsoft HCK network
> tests on a pair of Windows 8 VMs and it has been verified that this patch
> fixes the problem.
> 

Suggested-by: Jan Beulich <jbeulich@xxxxxxxx>
(or Reported-by, whatever you like better)

> Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>

Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>

> Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
> Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
> Cc: David Vrabel <david.vrabel@xxxxxxxxxx>
> ---
>  drivers/net/xen-netback/netback.c |   60 
> +++++++++++++++++--------------------
>  1 file changed, 28 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/net/xen-netback/netback.c 
> b/drivers/net/xen-netback/netback.c
> index acf1392..56c3e5a 100644
> --- a/drivers/net/xen-netback/netback.c
> +++ b/drivers/net/xen-netback/netback.c
> @@ -1199,42 +1199,40 @@ static int checksum_setup_ip(struct xenvif *vif, 
> struct sk_buff *skb,
>  
>       switch (ip_hdr(skb)->protocol) {
>       case IPPROTO_TCP:
> +             err = maybe_pull_tail(skb,
> +                                   off + sizeof(struct tcphdr),
> +                                   MAX_IP_HDR_LEN);
> +             if (err < 0)
> +                     goto out;
> +
>               if (!skb_partial_csum_set(skb, off,
>                                         offsetof(struct tcphdr, check)))
>                       goto out;
>  
> -             if (recalculate_partial_csum) {
> -                     err = maybe_pull_tail(skb,
> -                                           off + sizeof(struct tcphdr),
> -                                           MAX_IP_HDR_LEN);
> -                     if (err < 0)
> -                             goto out;
> -
> +             if (recalculate_partial_csum)
>                       tcp_hdr(skb)->check =
>                               ~csum_tcpudp_magic(ip_hdr(skb)->saddr,
>                                                  ip_hdr(skb)->daddr,
>                                                  skb->len - off,
>                                                  IPPROTO_TCP, 0);
> -             }
>               break;
>       case IPPROTO_UDP:
> +             err = maybe_pull_tail(skb,
> +                                   off + sizeof(struct udphdr),
> +                                   MAX_IP_HDR_LEN);
> +             if (err < 0)
> +                     goto out;
> +
>               if (!skb_partial_csum_set(skb, off,
>                                         offsetof(struct udphdr, check)))
>                       goto out;
>  
> -             if (recalculate_partial_csum) {
> -                     err = maybe_pull_tail(skb,
> -                                           off + sizeof(struct udphdr),
> -                                           MAX_IP_HDR_LEN);
> -                     if (err < 0)
> -                             goto out;
> -
> +             if (recalculate_partial_csum)
>                       udp_hdr(skb)->check =
>                               ~csum_tcpudp_magic(ip_hdr(skb)->saddr,
>                                                  ip_hdr(skb)->daddr,
>                                                  skb->len - off,
>                                                  IPPROTO_UDP, 0);
> -             }
>               break;
>       default:
>               goto out;
> @@ -1342,42 +1340,40 @@ static int checksum_setup_ipv6(struct xenvif *vif, 
> struct sk_buff *skb,
>  
>       switch (nexthdr) {
>       case IPPROTO_TCP:
> +             err = maybe_pull_tail(skb,
> +                                   off + sizeof(struct tcphdr),
> +                                   MAX_IPV6_HDR_LEN);
> +             if (err < 0)
> +                     goto out;
> + 
>               if (!skb_partial_csum_set(skb, off,
>                                         offsetof(struct tcphdr, check)))
>                       goto out;
>  
> -             if (recalculate_partial_csum) {
> -                     err = maybe_pull_tail(skb,
> -                                           off + sizeof(struct tcphdr),
> -                                           MAX_IPV6_HDR_LEN);
> -                     if (err < 0)
> -                             goto out;
> -
> +             if (recalculate_partial_csum)
>                       tcp_hdr(skb)->check =
>                               ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
>                                                &ipv6_hdr(skb)->daddr,
>                                                skb->len - off,
>                                                IPPROTO_TCP, 0);
> -             }
>               break;
>       case IPPROTO_UDP:
> +             err = maybe_pull_tail(skb,
> +                                   off + sizeof(struct udphdr),
> +                                   MAX_IPV6_HDR_LEN);
> +             if (err < 0)
> +                     goto out;
> +
>               if (!skb_partial_csum_set(skb, off,
>                                         offsetof(struct udphdr, check)))
>                       goto out;
>  
> -             if (recalculate_partial_csum) {
> -                     err = maybe_pull_tail(skb,
> -                                           off + sizeof(struct udphdr),
> -                                           MAX_IPV6_HDR_LEN);
> -                     if (err < 0)
> -                             goto out;
> -
> +             if (recalculate_partial_csum)
>                       udp_hdr(skb)->check =
>                               ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
>                                                &ipv6_hdr(skb)->daddr,
>                                                skb->len - off,
>                                                IPPROTO_UDP, 0);
> -             }
>               break;
>       default:
>               goto out;
> -- 
> 1.7.10.4
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx 
> http://lists.xen.org/xen-devel 



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel


 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.