bpftool: Support sysctl hook
Add support for recently added BPF_PROG_TYPE_CGROUP_SYSCTL program type
and BPF_CGROUP_SYSCTL attach type.
Example of bpftool output with sysctl program from selftests:
# bpftool p load ./test_sysctl_prog.o /mnt/bpf/sysctl_prog type cgroup/sysctl
# bpftool p l
9: cgroup_sysctl name sysctl_tcp_mem tag
0dd05f81a8d0d52e gpl
loaded_at 2019-04-16T12:57:27-0700 uid 0
xlated 1008B jited 623B memlock 4096B
# bpftool c a /mnt/cgroup2/bla sysctl id 9
# bpftool c t
CgroupPath
ID AttachType AttachFlags Name
/mnt/cgroup2/bla
9 sysctl sysctl_tcp_mem
# bpftool c d /mnt/cgroup2/bla sysctl id 9
# bpftool c t
CgroupPath
ID AttachType AttachFlags Name
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>