net: add ndo to setup/query xdp prog in adapter rx

Add one new netdev op for drivers implementing the BPF_PROG_TYPE_XDP
filter. The single op is used for both setup/query of the xdp program,
modelled after ndo_setup_tc.

Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 49736a31acaa38846f175a305545a4083c540af5..fab9a1c2a2ac06324eb6686123bcc12774b0d302 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -63,6 +63,7 @@ struct wpan_dev;
 struct mpls_dev;
 /* UDP Tunnel offloads */
 struct udp_tunnel_info;
+struct bpf_prog;
 
 void netdev_set_default_ethtool_ops(struct net_device *dev,
                                    const struct ethtool_ops *ops);
@@ -799,6 +800,33 @@ struct tc_to_netdev {
        };
 };
 
+/* These structures hold the attributes of xdp state that are being passed
+ * to the netdevice through the xdp op.
+ */
+enum xdp_netdev_command {
+       /* Set or clear a bpf program used in the earliest stages of packet
+        * rx. The prog will have been loaded as BPF_PROG_TYPE_XDP. The callee
+        * is responsible for calling bpf_prog_put on any old progs that are
+        * stored. In case of error, the callee need not release the new prog
+        * reference, but on success it takes ownership and must bpf_prog_put
+        * when it is no longer used.
+        */
+       XDP_SETUP_PROG,
+       /* Check if a bpf program is set on the device.  The callee should
+        * return true if a program is currently attached and running.
+        */
+       XDP_QUERY_PROG,
+};
+
+struct netdev_xdp {
+       enum xdp_netdev_command command;
+       union {
+               /* XDP_SETUP_PROG */
+               struct bpf_prog *prog;
+               /* XDP_QUERY_PROG */
+               bool prog_attached;
+       };
+};
 
 /*
  * This structure defines the management hooks for network devices.
@@ -1087,6 +1115,9 @@ struct tc_to_netdev {
  *     appropriate rx headroom value allows avoiding skb head copy on
  *     forward. Setting a negative value resets the rx headroom to the
  *     default value.
+ * 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.
  *
  */
 struct net_device_ops {
@@ -1271,6 +1302,8 @@ struct net_device_ops {
                                                       struct sk_buff *skb);
        void                    (*ndo_set_rx_headroom)(struct net_device *dev,
                                                       int needed_headroom);
+       int                     (*ndo_xdp)(struct net_device *dev,
+                                          struct netdev_xdp *xdp);
 };
 
 /**
@@ -3257,6 +3290,7 @@ int dev_get_phys_port_id(struct net_device *dev,
 int dev_get_phys_port_name(struct net_device *dev,
                           char *name, size_t len);
 int dev_change_proto_down(struct net_device *dev, bool proto_down);
+int dev_change_xdp_fd(struct net_device *dev, int fd);
 struct sk_buff *validate_xmit_skb_list(struct sk_buff *skb, struct net_device *dev);
 struct sk_buff *dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
                                    struct netdev_queue *txq, int *ret);

diff --git a/net/core/dev.c b/net/core/dev.c
index 7894e406c80684754fac5d144f2b40a18897f153..2a9c39f8824e027cbf0ea344f64273bdf971dce9 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -94,6 +94,7 @@
 #include <linux/ethtool.h>
 #include <linux/notifier.h>
 #include <linux/skbuff.h>
+#include <linux/bpf.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
 #include <net/busy_poll.h>
@@ -6614,6 +6615,38 @@ int dev_change_proto_down(struct net_device *dev, bool proto_down)
 }
 EXPORT_SYMBOL(dev_change_proto_down);
 
+/**
+ *     dev_change_xdp_fd - set or clear a bpf program for a device rx path
+ *     @dev: device
+ *     @fd: new program fd or negative value to clear
+ *
+ *     Set or clear a bpf program for a device
+ */
+int dev_change_xdp_fd(struct net_device *dev, int fd)
+{
+       const struct net_device_ops *ops = dev->netdev_ops;
+       struct bpf_prog *prog = NULL;
+       struct netdev_xdp xdp = {};
+       int err;
+
+       if (!ops->ndo_xdp)
+               return -EOPNOTSUPP;
+       if (fd >= 0) {
+               prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_XDP);
+               if (IS_ERR(prog))
+                       return PTR_ERR(prog);
+       }
+
+       xdp.command = XDP_SETUP_PROG;
+       xdp.prog = prog;
+       err = ops->ndo_xdp(dev, &xdp);
+       if (err < 0 && prog)
+               bpf_prog_put(prog);
+
+       return err;
+}
+EXPORT_SYMBOL(dev_change_xdp_fd);
+
 /**
  *     dev_new_index   -       allocate an ifindex
  *     @net: the applicable net namespace