net: Add IFLA_XDP_PROG_ID

Expose prog_id through IFLA_XDP_PROG_ID.  This patch
makes modification to generic_xdp.  The later patches will
modify other xdp-supported drivers.

prog_id is added to struct net_dev_xdp.

iproute2 patch will be followed. Here is how the 'ip link'
will look like:
> ip link show eth0
3: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 xdp(prog_id:1) qdisc fq_codel state UP mode DEFAULT group default qlen 1000

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index ad98a83f1332f3d27a5af5b5e89f28079e26c81d..7c7118b3bd692831e1c58e22c017d6985169b301 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -824,7 +824,10 @@ struct netdev_xdp {
                        struct netlink_ext_ack *extack;
                };
                /* XDP_QUERY_PROG */
-               bool prog_attached;
+               struct {
+                       bool prog_attached;
+                       u32 prog_id;
+               };
        };
 };
 
@@ -3302,7 +3305,7 @@ struct sk_buff *dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
 typedef int (*xdp_op_t)(struct net_device *dev, struct netdev_xdp *xdp);
 int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack,
                      int fd, u32 flags);
-bool __dev_xdp_attached(struct net_device *dev, xdp_op_t xdp_op);
+bool __dev_xdp_attached(struct net_device *dev, xdp_op_t xdp_op, u32 *prog_id);
 
 int __dev_forward_skb(struct net_device *dev, struct sk_buff *skb);
 int dev_forward_skb(struct net_device *dev, struct sk_buff *skb);

diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 8ed679fe603fcf013da907a6318b5a92f3ae681a..dd88375a6580268fe996282bbfd4f5e7a3c4b109 100644 (file)
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -907,6 +907,7 @@ enum {
        IFLA_XDP_FD,
        IFLA_XDP_ATTACHED,
        IFLA_XDP_FLAGS,
+       IFLA_XDP_PROG_ID,
        __IFLA_XDP_MAX,
 };
 

diff --git a/net/core/dev.c b/net/core/dev.c
index 8658074ecad60b44ac7db2ac229773270eebdb65..b8d6dd9e8b5c7776d078738a2fd956e8e437aa67 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4342,13 +4342,12 @@ static struct static_key generic_xdp_needed __read_mostly;
 
 static int generic_xdp_install(struct net_device *dev, struct netdev_xdp *xdp)
 {
+       struct bpf_prog *old = rtnl_dereference(dev->xdp_prog);
        struct bpf_prog *new = xdp->prog;
        int ret = 0;
 
        switch (xdp->command) {
-       case XDP_SETUP_PROG: {
-               struct bpf_prog *old = rtnl_dereference(dev->xdp_prog);
-
+       case XDP_SETUP_PROG:
                rcu_assign_pointer(dev->xdp_prog, new);
                if (old)
                        bpf_prog_put(old);
@@ -4360,10 +4359,10 @@ static int generic_xdp_install(struct net_device *dev, struct netdev_xdp *xdp)
                        dev_disable_lro(dev);
                }
                break;
-       }
 
        case XDP_QUERY_PROG:
-               xdp->prog_attached = !!rcu_access_pointer(dev->xdp_prog);
+               xdp->prog_attached = !!old;
+               xdp->prog_id = old ? old->aux->id : 0;
                break;
 
        default:
@@ -6937,7 +6936,8 @@ int dev_change_proto_down(struct net_device *dev, bool proto_down)
 }
 EXPORT_SYMBOL(dev_change_proto_down);
 
-bool __dev_xdp_attached(struct net_device *dev, xdp_op_t xdp_op)
+bool __dev_xdp_attached(struct net_device *dev, xdp_op_t xdp_op,
+                       u32 *prog_id)
 {
        struct netdev_xdp xdp;
 
@@ -6946,6 +6946,9 @@ bool __dev_xdp_attached(struct net_device *dev, xdp_op_t xdp_op)
 
        /* Query must always succeed. */
        WARN_ON(xdp_op(dev, &xdp) < 0);
+       if (prog_id)
+               *prog_id = xdp.prog_id;
+
        return xdp.prog_attached;
 }
 
@@ -6991,10 +6994,10 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack,
                xdp_chk = generic_xdp_install;
 
        if (fd >= 0) {
-               if (xdp_chk && __dev_xdp_attached(dev, xdp_chk))
+               if (xdp_chk && __dev_xdp_attached(dev, xdp_chk, NULL))
                        return -EEXIST;
                if ((flags & XDP_FLAGS_UPDATE_IF_NOEXIST) &&
-                   __dev_xdp_attached(dev, xdp_op))
+                   __dev_xdp_attached(dev, xdp_op, NULL))
                        return -EBUSY;
 
                prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_XDP);

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 2769ad9834d1135485f21185ce402d28b11a4299..3aa57848a8955bc4d2606103f9500319948f0727 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -39,6 +39,7 @@
 #include <linux/if_vlan.h>
 #include <linux/pci.h>
 #include <linux/etherdevice.h>
+#include <linux/bpf.h>
 
 #include <linux/uaccess.h>
 
@@ -899,7 +900,8 @@ static size_t rtnl_port_size(const struct net_device *dev,
 static size_t rtnl_xdp_size(void)
 {
        size_t xdp_size = nla_total_size(0) +   /* nest IFLA_XDP */
-                         nla_total_size(1);    /* XDP_ATTACHED */
+                         nla_total_size(1) +   /* XDP_ATTACHED */
+                         nla_total_size(4);    /* XDP_PROG_ID */
 
        return xdp_size;
 }
@@ -1248,15 +1250,20 @@ static int rtnl_fill_link_ifmap(struct sk_buff *skb, struct net_device *dev)
        return 0;
 }
 
-static u8 rtnl_xdp_attached_mode(struct net_device *dev)
+static u8 rtnl_xdp_attached_mode(struct net_device *dev, u32 *prog_id)
 {
        const struct net_device_ops *ops = dev->netdev_ops;
+       const struct bpf_prog *generic_xdp_prog;
 
        ASSERT_RTNL();
 
-       if (rcu_access_pointer(dev->xdp_prog))
+       *prog_id = 0;
+       generic_xdp_prog = rtnl_dereference(dev->xdp_prog);
+       if (generic_xdp_prog) {
+               *prog_id = generic_xdp_prog->aux->id;
                return XDP_ATTACHED_SKB;
-       if (ops->ndo_xdp && __dev_xdp_attached(dev, ops->ndo_xdp))
+       }
+       if (ops->ndo_xdp && __dev_xdp_attached(dev, ops->ndo_xdp, prog_id))
                return XDP_ATTACHED_DRV;
 
        return XDP_ATTACHED_NONE;
@@ -1265,6 +1272,7 @@ static u8 rtnl_xdp_attached_mode(struct net_device *dev)
 static int rtnl_xdp_fill(struct sk_buff *skb, struct net_device *dev)
 {
        struct nlattr *xdp;
+       u32 prog_id;
        int err;
 
        xdp = nla_nest_start(skb, IFLA_XDP);
@@ -1272,10 +1280,16 @@ static int rtnl_xdp_fill(struct sk_buff *skb, struct net_device *dev)
                return -EMSGSIZE;
 
        err = nla_put_u8(skb, IFLA_XDP_ATTACHED,
-                        rtnl_xdp_attached_mode(dev));
+                        rtnl_xdp_attached_mode(dev, &prog_id));
        if (err)
                goto err_cancel;
 
+       if (prog_id) {
+               err = nla_put_u32(skb, IFLA_XDP_PROG_ID, prog_id);
+               if (err)
+                       goto err_cancel;
+       }
+
        nla_nest_end(skb, xdp);
        return 0;
 
@@ -1553,6 +1567,7 @@ static const struct nla_policy ifla_xdp_policy[IFLA_XDP_MAX + 1] = {
        [IFLA_XDP_FD]           = { .type = NLA_S32 },
        [IFLA_XDP_ATTACHED]     = { .type = NLA_U8 },
        [IFLA_XDP_FLAGS]        = { .type = NLA_U32 },
+       [IFLA_XDP_PROG_ID]      = { .type = NLA_U32 },
 };
 
 static const struct rtnl_link_ops *linkinfo_to_kind_ops(const struct nlattr *nla)
@@ -2225,7 +2240,7 @@ static int do_setlink(const struct sk_buff *skb,
                if (err < 0)
                        goto errout;
 
-               if (xdp[IFLA_XDP_ATTACHED]) {
+               if (xdp[IFLA_XDP_ATTACHED] || xdp[IFLA_XDP_PROG_ID]) {
                        err = -EINVAL;
                        goto errout;
                }