From 74fc8801edc279fb5f778eb91df48e4d3cd951a2 Mon Sep 17 00:00:00 2001 From: Kui-Feng Lee Date: Fri, 21 Apr 2023 14:41:31 -0700 Subject: bpftool: Show map IDs along with struct_ops links. A new link type, BPF_LINK_TYPE_STRUCT_OPS, was added to attach struct_ops to links. (226bc6ae6405) It would be helpful for users to know which map is associated with the link. The assumption was that every link is associated with a BPF program, but this does not hold true for struct_ops. It would be better to display map_id instead of prog_id for struct_ops links. However, some tools may rely on the old assumption and need a prog_id. The discussion on the mailing list suggests that tools should parse JSON format. We will maintain the existing JSON format by adding a map_id without removing prog_id. As for plain text format, we will remove prog_id from the header line and add a map_id for struct_ops links. Signed-off-by: Kui-Feng Lee Signed-off-by: Daniel Borkmann Reviewed-by: Quentin Monnet Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20230421214131.352662-1-kuifeng@meta.com --- tools/bpf/bpftool/link.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'tools/bpf') diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c index d98dbc50cf4c..243b74e18e51 100644 --- a/tools/bpf/bpftool/link.c +++ b/tools/bpf/bpftool/link.c @@ -212,7 +212,10 @@ static int show_link_close_json(int fd, struct bpf_link_info *info) case BPF_LINK_TYPE_NETFILTER: netfilter_dump_json(info, json_wtr); break; - + case BPF_LINK_TYPE_STRUCT_OPS: + jsonw_uint_field(json_wtr, "map_id", + info->struct_ops.map_id); + break; default: break; } @@ -245,7 +248,10 @@ static void show_link_header_plain(struct bpf_link_info *info) else printf("type %u ", info->type); - printf("prog %u ", info->prog_id); + if (info->type == BPF_LINK_TYPE_STRUCT_OPS) + printf("map %u ", info->struct_ops.map_id); + else + printf("prog %u ", info->prog_id); } static void show_link_attach_type_plain(__u32 attach_type) -- cgit v1.2.3