xen-netback: enable IPv6 TCP GSO to the guest

This patch adds code to handle SKB_GSO_TCPV6 skbs and construct appropriate
extra or prefix segments to pass the large packet to the frontend. New
xenstore flags, feature-gso-tcpv6 and feature-gso-tcpv6-prefix, are sampled
to determine if the frontend is capable of handling such packets.

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

1 files changed, 38 insertions, 10 deletions

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 0e327d46a139..828fdab4f1a4 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -142,7 +142,7 @@ static int max_required_rx_slots(struct xenvif *vif)
         int max = DIV_ROUND_UP(vif->dev->mtu, PAGE_SIZE);
 
         /* XXX FIXME: RX path dependent on MAX_SKB_FRAGS */
-        if (vif->can_sg || vif->gso || vif->gso_prefix)
+        if (vif->can_sg || vif->gso_mask || vif->gso_prefix_mask)
                 max += MAX_SKB_FRAGS + 1; /* extra_info + frags */
 
         return max;
@@ -314,6 +314,7 @@ static struct xenvif_rx_meta *get_next_rx_buffer(struct xenvif *vif,
         req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
 
         meta = npo->meta + npo->meta_prod++;
+        meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
         meta->gso_size = 0;
         meta->size = 0;
         meta->id = req->id;
@@ -336,6 +337,7 @@ static void xenvif_gop_frag_copy(struct xenvif *vif, struct sk_buff *skb,
         struct gnttab_copy *copy_gop;
         struct xenvif_rx_meta *meta;
         unsigned long bytes;
+        int gso_type;
 
         /* Data must not cross a page boundary. */
         BUG_ON(size + offset > PAGE_SIZE<<compound_order(page));
@@ -394,7 +396,14 @@ static void xenvif_gop_frag_copy(struct xenvif *vif, struct sk_buff *skb,
                 }
 
                 /* Leave a gap for the GSO descriptor. */
-                if (*head && skb_shinfo(skb)->gso_size && !vif->gso_prefix)
+                if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
+                        gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
+                else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
+                        gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
+                else
+                        gso_type = XEN_NETIF_GSO_TYPE_NONE;
+
+                if (*head && ((1 << gso_type) & vif->gso_mask))
                         vif->rx.req_cons++;
 
                 *head = 0; /* There must be something in this buffer now. */
@@ -425,14 +434,28 @@ static int xenvif_gop_skb(struct sk_buff *skb,
         unsigned char *data;
         int head = 1;
         int old_meta_prod;
+        int gso_type;
+        int gso_size;
 
         old_meta_prod = npo->meta_prod;
 
+        if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) {
+                gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
+                gso_size = skb_shinfo(skb)->gso_size;
+        } else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) {
+                gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
+                gso_size = skb_shinfo(skb)->gso_size;
+        } else {
+                gso_type = XEN_NETIF_GSO_TYPE_NONE;
+                gso_size = 0;
+        }
+
         /* Set up a GSO prefix descriptor, if necessary */
-        if (skb_shinfo(skb)->gso_size && vif->gso_prefix) {
+        if ((1 << skb_shinfo(skb)->gso_type) & vif->gso_prefix_mask) {
                 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
                 meta = npo->meta + npo->meta_prod++;
-                meta->gso_size = skb_shinfo(skb)->gso_size;
+                meta->gso_type = gso_type;
+                meta->gso_size = gso_size;
                 meta->size = 0;
                 meta->id = req->id;
         }
@@ -440,10 +463,13 @@ static int xenvif_gop_skb(struct sk_buff *skb,
         req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
         meta = npo->meta + npo->meta_prod++;
 
-        if (!vif->gso_prefix)
-                meta->gso_size = skb_shinfo(skb)->gso_size;
-        else
+        if ((1 << gso_type) & vif->gso_mask) {
+                meta->gso_type = gso_type;
+                meta->gso_size = gso_size;
+        } else {
+                meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
                 meta->gso_size = 0;
+        }
 
         meta->size = 0;
         meta->id = req->id;
@@ -589,7 +615,8 @@ void xenvif_rx_action(struct xenvif *vif)
 
                 vif = netdev_priv(skb->dev);
 
-                if (vif->meta[npo.meta_cons].gso_size && vif->gso_prefix) {
+                if ((1 << vif->meta[npo.meta_cons].gso_type) &
+                    vif->gso_prefix_mask) {
                         resp = RING_GET_RESPONSE(&vif->rx,
                                                  vif->rx.rsp_prod_pvt++);
 
@@ -626,7 +653,8 @@ void xenvif_rx_action(struct xenvif *vif)
                                         vif->meta[npo.meta_cons].size,
                                         flags);
 
-                if (vif->meta[npo.meta_cons].gso_size && !vif->gso_prefix) {
+                if ((1 << vif->meta[npo.meta_cons].gso_type) &
+                    vif->gso_mask) {
                         struct xen_netif_extra_info *gso =
                                 (struct xen_netif_extra_info *)
                                 RING_GET_RESPONSE(&vif->rx,
@@ -634,8 +662,8 @@ void xenvif_rx_action(struct xenvif *vif)
 
                         resp->flags |= XEN_NETRXF_extra_info;
 
+                        gso->u.gso.type = vif->meta[npo.meta_cons].gso_type;
                         gso->u.gso.size = vif->meta[npo.meta_cons].gso_size;
-                        gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
                         gso->u.gso.pad = 0;
                         gso->u.gso.features = 0;