bpf: Document BPF_PROG_ATTACH syscall command

Document the prog attach command in more detail, based on git commits:
* commit f432455148 ("bpf: add BPF_PROG_ATTACH and BPF_PROG_DETACH
  commands")
* commit 4f738adba3 ("bpf: create tcp_bpf_ulp allowing BPF to monitor
  socket TX/RX data")
* commit f4364dcfc8 ("media: rc: introduce BPF_PROG_LIRC_MODE2")
* commit d58e468b11 ("flow_dissector: implements flow dissector BPF
  hook")

Signed-off-by: Joe Stringer <joe@cilium.io>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210302171947.2268128-6-joe@cilium.io
This commit is contained in:
Joe Stringer 2021-03-02 09:19:37 -08:00 committed by Alexei Starovoitov
parent 8aacb3c8d1
commit 32e76b187a

View File

@ -253,6 +253,43 @@ union bpf_iter_link_info {
* Attach an eBPF program to a *target_fd* at the specified * Attach an eBPF program to a *target_fd* at the specified
* *attach_type* hook. * *attach_type* hook.
* *
* The *attach_type* specifies the eBPF attachment point to
* attach the program to, and must be one of *bpf_attach_type*
* (see below).
*
* The *attach_bpf_fd* must be a valid file descriptor for a
* loaded eBPF program of a cgroup, flow dissector, LIRC, sockmap
* or sock_ops type corresponding to the specified *attach_type*.
*
* The *target_fd* must be a valid file descriptor for a kernel
* object which depends on the attach type of *attach_bpf_fd*:
*
* **BPF_PROG_TYPE_CGROUP_DEVICE**,
* **BPF_PROG_TYPE_CGROUP_SKB**,
* **BPF_PROG_TYPE_CGROUP_SOCK**,
* **BPF_PROG_TYPE_CGROUP_SOCK_ADDR**,
* **BPF_PROG_TYPE_CGROUP_SOCKOPT**,
* **BPF_PROG_TYPE_CGROUP_SYSCTL**,
* **BPF_PROG_TYPE_SOCK_OPS**
*
* Control Group v2 hierarchy with the eBPF controller
* enabled. Requires the kernel to be compiled with
* **CONFIG_CGROUP_BPF**.
*
* **BPF_PROG_TYPE_FLOW_DISSECTOR**
*
* Network namespace (eg /proc/self/ns/net).
*
* **BPF_PROG_TYPE_LIRC_MODE2**
*
* LIRC device path (eg /dev/lircN). Requires the kernel
* to be compiled with **CONFIG_BPF_LIRC_MODE2**.
*
* **BPF_PROG_TYPE_SK_SKB**,
* **BPF_PROG_TYPE_SK_MSG**
*
* eBPF map of socket type (eg **BPF_MAP_TYPE_SOCKHASH**).
*
* Return * Return
* Returns zero on success. On error, -1 is returned and *errno* * Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately. * is set appropriately.