Commit e948947a authored May 31, 2020 by Jakub Sitnicki Committed by Alexei Starovoitov Jun 01, 2020

bpftool: Support link show for netns-attached links



Make `bpf link show` aware of new link type, that is links attached to
netns. When listing netns-attached links, display netns inode number as its
identifier and link attach type.

Sample session:

  # readlink /proc/self/ns/net
  net:[4026532251]
  # bpftool prog show
  357: flow_dissector  tag a04f5eef06a7f555  gpl
          loaded_at 2020-05-30T16:53:51+0200  uid 0
          xlated 16B  jited 37B  memlock 4096B
  358: flow_dissector  tag a04f5eef06a7f555  gpl
          loaded_at 2020-05-30T16:53:51+0200  uid 0
          xlated 16B  jited 37B  memlock 4096B
  # bpftool link show
  108: netns  prog 357
          netns_ino 4026532251  attach_type flow_dissector
  # bpftool link -jp show
  [{
          "id": 108,
          "type": "netns",
          "prog_id": 357,
          "netns_ino": 4026532251,
          "attach_type": "flow_dissector"
      }
  ]

  (... after netns is gone ...)

  # bpftool link show
  108: netns  prog 357
          netns_ino 0  attach_type flow_dissector
  # bpftool link -jp show
  [{
          "id": 108,
          "type": "netns",
          "prog_id": 357,
          "netns_ino": 0,
          "attach_type": "flow_dissector"
      }
  ]

Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200531082846.2117903-9-jakub@cloudflare.com

parent be6e1981

tools/bpf/bpftool/link.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -17,6 +17,7 @@ static const char * const link_type_name[] = {
		[BPF_LINK_TYPE_TRACING] = "tracing",
		[BPF_LINK_TYPE_CGROUP] = "cgroup",
		[BPF_LINK_TYPE_ITER] = "iter",
		[BPF_LINK_TYPE_NETNS] = "netns",
		};

		static int link_parse_fd(int argc, char **argv)
		@@ -122,6 +123,11 @@ static int show_link_close_json(int fd, struct bpf_link_info *info)
		info->cgroup.cgroup_id);
		show_link_attach_type_json(info->cgroup.attach_type, json_wtr);
		break;
		case BPF_LINK_TYPE_NETNS:
		jsonw_uint_field(json_wtr, "netns_ino",
		info->netns.netns_ino);
		show_link_attach_type_json(info->netns.attach_type, json_wtr);
		break;
		default:
		break;
		}
		@@ -190,6 +196,10 @@ static int show_link_close_plain(int fd, struct bpf_link_info *info)
		printf("\n\tcgroup_id %zu ", (size_t)info->cgroup.cgroup_id);
		show_link_attach_type_plain(info->cgroup.attach_type);
		break;
		case BPF_LINK_TYPE_NETNS:
		printf("\n\tnetns_ino %u ", info->netns.netns_ino);
		show_link_attach_type_plain(info->netns.attach_type);
		break;
		default:
		break;
		}

Admin message