Libbpf userspace function bpf_program__attach_netkit

1.3.0

Attach a netkit program to a netkit network interface.

Definition

struct bpf_link * bpf_program__attach_netkit(const struct bpf_program *prog, int ifindex, const struct bpf_netkit_opts *opts);

Parameters

• prog: BPF program to attach
• ifindex: index of the network interface to attach the program to
• opts: netkit options

Return

Reference to the newly created BPF link; or NULL is returned on error, error code is stored in errno

struct bpf_netkit_opts

struct bpf_netkit_opts {
    /* size of this struct, for forward/backward compatibility */
    size_t sz;
    __u32 flags;
    __u32 relative_fd;
    __u32 relative_id;
    __u64 expected_revision;
    size_t :0;
};

flags

Flags to modify attachment behavior.

BPF_F_ID - If set, identify a relative object based on the ID in relative_id. Otherwise use the FD in relative_fd. BPF_F_LINK - If set, the relative_fd/relative_id fields refer to links, not programs. BPF_F_REPLACE - If set, replace the existing program/link with the relative one. BPF_F_BEFORE - If set, add the new program/link before the relative one. BPF_F_AFTER - If set, add the new program/link after the relative one.

relative_fd

File descriptor of the relative object.

relative_id

ID of the relative object.

expected_revision

The current mprog revision. A revision number shared by all programs attached to the same hook point. It can be queried via BPF_PROG_QUERY / bpf_prog_query / bpf_prog_query_opts.

Usage

Netkit programs essentially TCX programs with more restrictions (namely that netkit programs can only attach to netkit links). Their attachment is very similar.

Example

Docs could be improved

This part of the docs is incomplete, contributions are very welcome