xen-netback: handle IPv6 TCP GSO packets from the guest

This patch adds a xenstore feature flag, festure-gso-tcpv6, to advertise
that netback can handle IPv6 TCP GSO packets. It creates SKB_GSO_TCPV6 skbs
if the frontend passes an extra segment with the new type
XEN_NETIF_GSO_TYPE_TCPV6 added to netif.h.

Signed-off-by: Paul Durrant <[email protected]>
Cc: Wei Liu <[email protected]>
Cc: David Vrabel <[email protected]>
Acked-by: Ian Campbell <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
3 files changed