[PATCH bpf-next v3 3/5] bpftool: Add link dump support for BPF_LINK_TYPE_SOCKMAP

[Yonghong Song <yonghong.song@linux.dev>]

An example output looks like:
  $ bpftool link
    1776: sk_skb  prog 49730
            map_id 0  attach_type sk_skb_verdict
            pids test_progs(8424)
    1777: sk_skb  prog 49755
            map_id 0  attach_type sk_skb_stream_verdict
            pids test_progs(8424)
    1778: sk_msg  prog 49770
            map_id 8208  attach_type sk_msg_verdict
            pids test_progs(8424)

Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
---
 tools/bpf/bpftool/link.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
index afde9d0c2ea1..5cd503b763d7 100644
--- a/tools/bpf/bpftool/link.c
+++ b/tools/bpf/bpftool/link.c
@@ -526,6 +526,10 @@ static int show_link_close_json(int fd, struct bpf_link_info *info)
 		show_link_ifindex_json(info->netkit.ifindex, json_wtr);
 		show_link_attach_type_json(info->netkit.attach_type, json_wtr);
 		break;
+	case BPF_LINK_TYPE_SOCKMAP:
+		jsonw_uint_field(json_wtr, "map_id", info->sockmap.map_id);
+		show_link_attach_type_json(info->sockmap.attach_type, json_wtr);
+		break;
 	case BPF_LINK_TYPE_XDP:
 		show_link_ifindex_json(info->xdp.ifindex, json_wtr);
 		break;
@@ -915,6 +919,11 @@ static int show_link_close_plain(int fd, struct bpf_link_info *info)
 		show_link_ifindex_plain(info->netkit.ifindex);
 		show_link_attach_type_plain(info->netkit.attach_type);
 		break;
+	case BPF_LINK_TYPE_SOCKMAP:
+		printf("\n\t");
+		printf("map_id %u  ", info->sockmap.map_id);
+		show_link_attach_type_plain(info->sockmap.attach_type);
+		break;
 	case BPF_LINK_TYPE_XDP:
 		printf("\n\t");
 		show_link_ifindex_plain(info->xdp.ifindex);
-- 
2.43.0