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| author |   Andrii Nakryiko <andriin@fb.com> | 2020-03-29 19:59:59 -0700 |
|---|---|---|
| committer |   Alexei Starovoitov <ast@kernel.org> | 2020-03-30 17:36:33 -0700 |
| commit | 0c991ebc8c69d29b7fc44db17075c5aa5253e2ab (patch) | |
| tree | e61172384e68887343d57f1e40d47c2e5ecc98cc /include/uapi/linux/bpf.h | |
| parent | bpf: Implement bpf_link-based cgroup BPF program attachment (diff) | |
| download | wireguard-linux-0c991ebc8c69d29b7fc44db17075c5aa5253e2ab.tar.xz wireguard-linux-0c991ebc8c69d29b7fc44db17075c5aa5253e2ab.zip | |
bpf: Implement bpf_prog replacement for an active bpf_cgroup_link
Add new operation (LINK_UPDATE), which allows to replace active bpf_prog from
under given bpf_link. Currently this is only supported for bpf_cgroup_link,
but will be extended to other kinds of bpf_links in follow-up patches.
For bpf_cgroup_link, implemented functionality matches existing semantics for
direct bpf_prog attachment (including BPF_F_REPLACE flag). User can either
unconditionally set new bpf_prog regardless of which bpf_prog is currently
active under given bpf_link, or, optionally, can specify expected active
bpf_prog. If active bpf_prog doesn't match expected one, no changes are
performed, old bpf_link stays intact and attached, operation returns
a failure.
cgroup_bpf_replace() operation is resolving race between auto-detachment and
bpf_prog update in the same fashion as it's done for bpf_link detachment,
except in this case update has no way of succeeding because of target cgroup
marked as dying. So in this case error is returned.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200330030001.2312810-3-andriin@fb.com
Diffstat (limited to 'include/uapi/linux/bpf.h')
| -rw-r--r-- | include/uapi/linux/bpf.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 37dffe5089a0..2e29a671d67e 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -112,6 +112,7 @@ enum bpf_cmd { BPF_MAP_UPDATE_BATCH, BPF_MAP_DELETE_BATCH, BPF_LINK_CREATE, + BPF_LINK_UPDATE, }; enum bpf_map_type { @@ -577,6 +578,17 @@ union bpf_attr { __u32 attach_type; /* attach type */ __u32 flags; /* extra flags */ } link_create; + + struct { /* struct used by BPF_LINK_UPDATE command */ + __u32 link_fd; /* link fd */ + /* new program fd to update link with */ + __u32 new_prog_fd; + __u32 flags; /* extra flags */ + /* expected link's program fd; is specified only if + * BPF_F_REPLACE flag is set in flags */ + __u32 old_prog_fd; + } link_update; + } __attribute__((aligned(8))); /* The description below is an attempt at providing documentation to eBPF |