bpf: add documentation for eBPF helpers (12-22)
Add documentation for eBPF helper functions to bpf.h user header file. This documentation can be parsed with the Python script provided in another commit of the patch series, in order to provide a RST document that can later be converted into a man page. The objective is to make the documentation easily understandable and accessible to all eBPF developers, including beginners. This patch contains descriptions for the following helper functions, all written by Alexei: - bpf_get_current_pid_tgid() - bpf_get_current_uid_gid() - bpf_get_current_comm() - bpf_skb_vlan_push() - bpf_skb_vlan_pop() - bpf_skb_get_tunnel_key() - bpf_skb_set_tunnel_key() - bpf_redirect() - bpf_perf_event_output() - bpf_get_stackid() - bpf_get_current_task() v4: - bpf_redirect(): Fix typo: "XDP_ABORT" changed to "XDP_ABORTED". Add note on bpf_redirect_map() providing better performance. Replace "Save for" with "Except for". - bpf_skb_vlan_push(): Clarify comment about invalidated verifier checks. - bpf_skb_vlan_pop(): Clarify comment about invalidated verifier checks. - bpf_skb_get_tunnel_key(): Add notes on tunnel_id, "collect metadata" mode, and example tunneling protocols with which it can be used. - bpf_skb_set_tunnel_key(): Add a reference to the description of bpf_skb_get_tunnel_key(). - bpf_perf_event_output(): Specify that, and for what purpose, the helper can be used with programs attached to TC and XDP. v3: - bpf_skb_get_tunnel_key(): Change and improve description and example. - bpf_redirect(): Improve description of BPF_F_INGRESS flag. - bpf_perf_event_output(): Fix first sentence of description. Delete wrong statement on context being evaluated as a struct pt_reg. Remove the long yet incomplete example. - bpf_get_stackid(): Add a note about PERF_MAX_STACK_DEPTH being configurable. Cc: Alexei Starovoitov <ast@kernel.org> Signed-off-by:Quentin Monnet <quentin.monnet@netronome.com> Acked-by:
Alexei Starovoitov <ast@kernel.org> Signed-off-by:
Daniel Borkmann <daniel@iogearbox.net>
parent
ad4a5223
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