[RFC PATCH 06/12] ixgbe: add initial support for xdp redirect

[John Fastabend]

There are optimizations we can add after the basic feature is
enabled. But, for now keep the patch simple.

Signed-off-by: John Fastabend <john.fastab...@gmail.com>
Acked-by: Daniel Borkmann <dan...@iogearbox.net>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |   41 ++++++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c 
b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index f1dbdf2..3db0473 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -2214,7 +2214,7 @@ static struct sk_buff *ixgbe_run_xdp(struct ixgbe_adapter 
*adapter,
                                     struct ixgbe_ring *rx_ring,
                                     struct xdp_buff *xdp)
 {
-       int result = IXGBE_XDP_PASS;
+       int err, result = IXGBE_XDP_PASS;
        struct bpf_prog *xdp_prog;
        u32 act;
 
@@ -2231,6 +2231,13 @@ static struct sk_buff *ixgbe_run_xdp(struct 
ixgbe_adapter *adapter,
        case XDP_TX:
                result = ixgbe_xmit_xdp_ring(adapter, xdp);
                break;
+       case XDP_REDIRECT:
+               err = xdp_do_redirect(adapter->netdev, xdp);
+               if (!err)
+                       result = IXGBE_XDP_TX;
+               else
+                       result = IXGBE_XDP_CONSUMED;
+               break;
        default:
                bpf_warn_invalid_xdp_action(act);
                /* fallthrough */
@@ -9823,6 +9830,37 @@ static int ixgbe_xdp(struct net_device *dev, struct 
netdev_xdp *xdp)
        }
 }
 
+static int ixgbe_xdp_xmit(struct net_device *dev, struct xdp_buff *xdp)
+{
+       struct ixgbe_adapter *adapter = netdev_priv(dev);
+       struct ixgbe_ring *ring;
+       int err;
+
+       if (unlikely(test_bit(__IXGBE_DOWN, &adapter->state)))
+               return -EINVAL;
+
+       /* During program transitions its possible adapter->xdp_prog is assigned
+        * but ring has not been configured yet. In this case simply abort xmit.
+        */
+       ring = adapter->xdp_prog ? adapter->xdp_ring[smp_processor_id()] : NULL;
+       if (unlikely(!ring))
+               return -EINVAL;
+
+       err = ixgbe_xmit_xdp_ring(adapter, xdp);
+       if (err != IXGBE_XDP_TX)
+               return -ENOMEM;
+
+       /* Force memory writes to complete before letting h/w know there
+        * are new descriptors to fetch.
+        */
+       wmb();
+
+       ring = adapter->xdp_ring[smp_processor_id()];
+       writel(ring->next_to_use, ring->tail);
+
+       return 0;
+}
+
 static const struct net_device_ops ixgbe_netdev_ops = {
        .ndo_open               = ixgbe_open,
        .ndo_stop               = ixgbe_close,
@@ -9869,6 +9907,7 @@ static int ixgbe_xdp(struct net_device *dev, struct 
netdev_xdp *xdp)
        .ndo_udp_tunnel_del     = ixgbe_del_udp_tunnel_port,
        .ndo_features_check     = ixgbe_features_check,
        .ndo_xdp                = ixgbe_xdp,
+       .ndo_xdp_xmit           = ixgbe_xdp_xmit,
 };
 
 /**