Add bpf_program__attach_cgroup(), which uses BPF_LINK_CREATE subcommand to create an FD-based kernel bpf_link. Also add low-level bpf_link_create() API. If expected_attach_type is not specified explicitly with bpf_program__set_expected_attach_type(), libbpf will try to determine proper attach type from BPF program's section definition. Also add support for bpf_link's underlying BPF program replacement: - unconditional through high-level bpf_link__update_program() API; - cmpxchg-like with specifying expected current BPF program through low-level bpf_link_update() API.
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| @@ -112,6 +112,7 @@ enum bpf_cmd { · 111 unmodified lines | ||
| 112 | 112 | BPF_MAP_UPDATE_BATCH, |
| 113 | 113 | BPF_MAP_DELETE_BATCH, |
| 114 | 114 | BPF_LINK_CREATE, |
| 115 | + BPF_LINK_UPDATE, | |
| 115 | 116 | }; |
| 116 | 117 | |
| 117 | 118 | enum bpf_map_type { |
| @@ -577,6 +578,17 @@ union bpf_attr { · 459 unmodified lines | ||
| 577 | 578 | __u32 attach_type; /* attach type */ |
| 578 | 579 | __u32 flags; /* extra flags */ |
| 579 | 580 | } link_create; |
| 581 | + | |
| 582 | + struct { /* struct used by BPF_LINK_UPDATE command */ | |
| 583 | + __u32 link_fd; /* link fd */ | |
| 584 | + /* new program fd to update link with */ | |
| 585 | + __u32 new_prog_fd; | |
| 586 | + __u32 flags; /* extra flags */ | |
| 587 | + /* expected link's program fd; is specified only if | |
| 588 | + * BPF_F_REPLACE flag is set in flags */ | |
| 589 | + __u32 old_prog_fd; | |
| 590 | + } link_update; | |
| 591 | + | |
| 580 | 592 | } __attribute__((aligned(8))); |
| 581 | 593 | |
| 582 | 594 | /* The description below is an attempt at providing documentation to eBPF |