bpf, xdp: Add bpf_link-based XDP attachment API

Add bpf_link-based API (bpf_xdp_link) to attach BPF XDP program through
BPF_LINK_CREATE command.

bpf_xdp_link is mutually exclusive with direct BPF program attachment,
previous BPF program should be detached prior to attempting to create a new
bpf_xdp_link attachment (for a given XDP mode). Once BPF link is attached, it
can't be replaced by other BPF program attachment or link attachment. It will
be detached only when the last BPF link FD is closed.

bpf_xdp_link will be auto-detached when net_device is shutdown, similarly to
how other BPF links behave (cgroup, flow_dissector). At that point bpf_link
will become defunct, but won't be destroyed until last FD is closed.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200722064603.3350758-5-andriin@fb.com
This commit is contained in:
Andrii Nakryiko
2020-07-21 23:45:57 -07:00
committed by Alexei Starovoitov
parent d4baa9368a
commit aa8d3a716b
4 changed files with 178 additions and 7 deletions

View File

@@ -888,6 +888,7 @@ struct bpf_prog_offload_ops;
struct netlink_ext_ack;
struct xdp_umem;
struct xdp_dev_bulk_queue;
struct bpf_xdp_link;
enum bpf_xdp_mode {
XDP_MODE_SKB = 0,
@@ -898,6 +899,7 @@ enum bpf_xdp_mode {
struct bpf_xdp_entity {
struct bpf_prog *prog;
struct bpf_xdp_link *link;
};
struct netdev_bpf {
@@ -3831,7 +3833,9 @@ struct sk_buff *dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
typedef int (*bpf_op_t)(struct net_device *dev, struct netdev_bpf *bpf);
int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack,
int fd, int expected_fd, u32 flags);
int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog);
u32 dev_xdp_prog_id(struct net_device *dev, enum bpf_xdp_mode mode);
int xdp_umem_query(struct net_device *dev, u16 queue_id);
int __dev_forward_skb(struct net_device *dev, struct sk_buff *skb);