Support dumping info of a cgroup_iter link. This includes
showing the cgroup's id and the order for walking the cgroup
hierarchy. Example output is as follows:
> bpftool link show
1: iter prog 2 target_name bpf_map
2: iter prog 3 target_name bpf_prog
3: iter prog 12 target_name cgroup cgroup_id 72 order self_only
> bpftool -p link show
[{
"id": 1,
"type": "iter",
"prog_id": 2,
"target_name": "bpf_map"
},{
"id": 2,
"type": "iter",
"prog_id": 3,
"target_name": "bpf_prog"
},{
"id": 3,
"type": "iter",
"prog_id": 12,
"target_name": "cgroup",
"cgroup_id": 72,
"order": "self_only"
}
]
Signed-off-by: Hao Luo <haoluo@google.com>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220829231828.1016835-1-haoluo@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@linux.dev>