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 <paul.durrant@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 15 insertions, 3 deletions

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 4271f8d1da7a..0e327d46a139 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1098,15 +1098,20 @@ static int xenvif_set_skb_gso(struct xenvif *vif,
                 return -EINVAL;
         }
 
-        /* Currently only TCPv4 S.O. is supported. */
-        if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) {
+        switch (gso->u.gso.type) {
+        case XEN_NETIF_GSO_TYPE_TCPV4:
+                skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
+                break;
+        case XEN_NETIF_GSO_TYPE_TCPV6:
+                skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
+                break;
+        default:
                 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
                 xenvif_fatal_tx_err(vif);
                 return -EINVAL;
         }
 
         skb_shinfo(skb)->gso_size = gso->u.gso.size;
-        skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 
         /* Header must be checked, and gso_segs computed. */
         skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 108e7523017a..02cb00bebdc9 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -105,6 +105,13 @@ static int netback_probe(struct xenbus_device *dev,
                         goto abort_transaction;
                 }
 
+                err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv6",
+                                    "%d", sg);
+                if (err) {
+                        message = "writing feature-gso-tcpv6";
+                        goto abort_transaction;
+                }
+
                 /* We support partial checksum setup for IPv6 packets */
                 err = xenbus_printf(xbt, dev->nodename,
                                     "feature-ipv6-csum-offload",