xdp: add bpf_redirect helper function

This adds support for a bpf_redirect helper function to the XDP
infrastructure. For now this only supports redirecting to the egress
path of a port.

In order to support drivers handling a xdp_buff natively this patches
uses a new ndo operation ndo_xdp_xmit() that takes pushes a xdp_buff
to the specified device.

If the program specifies either (a) an unknown device or (b) a device
that does not support the operation a BPF warning is thrown and the
XDP_ABORTED error code is returned.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 779b23595596..77f5376005e6 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -66,6 +66,7 @@ struct mpls_dev;
 /* UDP Tunnel offloads */
 struct udp_tunnel_info;
 struct bpf_prog;
+struct xdp_buff;
 
 void netdev_set_default_ethtool_ops(struct net_device *dev,
                                     const struct ethtool_ops *ops);
@@ -1138,6 +1139,9 @@ struct xfrmdev_ops {
  * int (*ndo_xdp)(struct net_device *dev, struct netdev_xdp *xdp);
  *      This function is used to set or query state related to XDP on the
  *      netdevice. See definition of enum xdp_netdev_command for details.
+ * int (*ndo_xdp_xmit)(struct net_device *dev, struct xdp_buff *xdp);
+ *      This function is used to submit a XDP packet for transmit on a
+ *      netdevice.
  *
  */
 struct net_device_ops {
@@ -1323,6 +1327,8 @@ struct net_device_ops {
                                                        int needed_headroom);
         int                     (*ndo_xdp)(struct net_device *dev,
                                            struct netdev_xdp *xdp);
+        int                     (*ndo_xdp_xmit)(struct net_device *dev,
+                                                struct xdp_buff *xdp);
 };
 
 /**