On Wed, Aug 16, 2023 at 5:56 PM Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote:
>
> Add support to dump tcx link information to bpftool. This adds a
> common helper show_link_ifindex_{plain,json}() which can be reused
> also for other link types. The plain text and json device output is
> the same format as in bpftool net dump.
>
> Below shows an example link dump output along with a cgroup link
> for comparison:
>
> # bpftool link
> [...]
> 10: cgroup prog 1977
> cgroup_id 1 attach_type cgroup_inet6_post_bind
> [...]
> 13: tcx prog 2053
> ifindex enp5s0(3) attach_type tcx_ingress
> 14: tcx prog 2080
> ifindex enp5s0(3) attach_type tcx_egress
> [...]
>
> Equivalent json output:
>
> # bpftool link --json
> [...]
> {
> "id": 10,
> "type": "cgroup",
> "prog_id": 1977,
> "cgroup_id": 1,
> "attach_type": "cgroup_inet6_post_bind"
> },
> [...]
> {
> "id": 13,
> "type": "tcx",
> "prog_id": 2053,
> "devname": "enp5s0",
> "ifindex": 3,
> "attach_type": "tcx_ingress"
> },
> {
> "id": 14,
> "type": "tcx",
> "prog_id": 2080,
> "devname": "enp5s0",
> "ifindex": 3,
> "attach_type": "tcx_egress"
> }
> [...]
>
> Suggested-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
> Reviewed-by: Quentin Monnet <quentin@xxxxxxxxxxxxx>
Thanks for your work. This patch looks good to me.
A minor nit below.
> ---
> tools/bpf/bpftool/link.c | 37 +++++++++++++++++++++++++++++++++++++
> 1 file changed, 37 insertions(+)
>
> diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
> index 65a168df63bc..a3774594f154 100644
> --- a/tools/bpf/bpftool/link.c
> +++ b/tools/bpf/bpftool/link.c
> @@ -150,6 +150,18 @@ static void show_link_attach_type_json(__u32 attach_type, json_writer_t *wtr)
> jsonw_uint_field(wtr, "attach_type", attach_type);
> }
>
> +static void show_link_ifindex_json(__u32 ifindex, json_writer_t *wtr)
> +{
> + char devname[IF_NAMESIZE] = "(unknown)";
> +
> + if (ifindex)
> + if_indextoname(ifindex, devname);
> + else
> + snprintf(devname, sizeof(devname), "(detached)");
> + jsonw_string_field(wtr, "devname", devname);
> + jsonw_uint_field(wtr, "ifindex", ifindex);
> +}
> +
> static bool is_iter_map_target(const char *target_name)
> {
> return strcmp(target_name, "bpf_map_elem") == 0 ||
> @@ -433,6 +445,10 @@ 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_TCX:
> + show_link_ifindex_json(info->tcx.ifindex, json_wtr);
> + show_link_attach_type_json(info->tcx.attach_type, json_wtr);
> + break;
> case BPF_LINK_TYPE_STRUCT_OPS:
> jsonw_uint_field(json_wtr, "map_id",
> info->struct_ops.map_id);
> @@ -509,6 +525,22 @@ static void show_link_attach_type_plain(__u32 attach_type)
> printf("attach_type %u ", attach_type);
> }
>
> +static void show_link_ifindex_plain(__u32 ifindex)
> +{
> + char devname[IF_NAMESIZE * 2] = "(unknown)";
> + char tmpname[IF_NAMESIZE];
> + char *ret = NULL;
> +
> + if (ifindex)
> + ret = if_indextoname(ifindex, tmpname);
> + else
> + snprintf(devname, sizeof(devname), "(detached)");
> + if (ret)
> + snprintf(devname, sizeof(devname), "%s(%d)",
> + tmpname, ifindex);
> + printf("ifindex %s ", devname);
> +}
This function looks a little strange to me. What about the change below?
static void show_link_ifindex_plain(__u32 ifindex)
{
char devname[IF_NAMESIZE] = "(unknown)";
if (ifindex) {
if_indextoname(ifindex, devname);
printf("ifindex %s(%d) ", devname, ifindex);
} else {
printf("ifindex (detached) ");
}
}
> +
> static void show_iter_plain(struct bpf_link_info *info)
> {
> const char *target_name = u64_to_ptr(info->iter.target_name);
> @@ -745,6 +777,11 @@ static int show_link_close_plain(int fd, struct bpf_link_info *info)
> case BPF_LINK_TYPE_NETFILTER:
> netfilter_dump_plain(info);
> break;
> + case BPF_LINK_TYPE_TCX:
> + printf("\n\t");
> + show_link_ifindex_plain(info->tcx.ifindex);
> + show_link_attach_type_plain(info->tcx.attach_type);
> + break;
> case BPF_LINK_TYPE_KPROBE_MULTI:
> show_kprobe_multi_plain(info);
> break;
> --
> 2.34.1
>
--
Regards
Yafang
