On Thu, Aug 1, 2019 at 2:04 AM Daniel T. Lee <danieltim...@gmail.com> wrote:
>
> By this commit, using `bpftool net detach`, the attached XDP prog can
> be detached. Detaching the BPF prog will be done through libbpf
> 'bpf_set_link_xdp_fd' with the progfd set to -1.
>
> Signed-off-by: Daniel T. Lee <danieltim...@gmail.com>
> ---
> Changes in v2:
> - command 'unload' changed to 'detach' for the consistency
>
> tools/bpf/bpftool/net.c | 55 ++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 54 insertions(+), 1 deletion(-)
>
> diff --git a/tools/bpf/bpftool/net.c b/tools/bpf/bpftool/net.c
> index f3b57660b303..2ae9a613b05c 100644
> --- a/tools/bpf/bpftool/net.c
> +++ b/tools/bpf/bpftool/net.c
> @@ -281,6 +281,31 @@ static int parse_attach_args(int argc, char **argv, int
> *progfd,
> return 0;
> }
>
> +static int parse_detach_args(int argc, char **argv,
> + enum net_attach_type *attach_type, int *ifindex)
> +{
> + if (!REQ_ARGS(2))
> + return -EINVAL;
> +
> + *attach_type = parse_attach_type(*argv);
> + if (*attach_type == __MAX_NET_ATTACH_TYPE) {
> + p_err("invalid net attach/detach type");
> + return -EINVAL;
> + }
> +
> + NEXT_ARG();
> + if (!REQ_ARGS(1))
> + return -EINVAL;
> +
> + *ifindex = if_nametoindex(*argv);
> + if (!*ifindex) {
> + p_err("Invalid ifname");
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> static int do_attach_detach_xdp(int *progfd, enum net_attach_type
> *attach_type,
> int *ifindex)
> {
> @@ -323,6 +348,31 @@ static int do_attach(int argc, char **argv)
> return 0;
> }
>
> +static int do_detach(int argc, char **argv)
> +{
> + enum net_attach_type attach_type;
> + int err, progfd, ifindex;
> +
> + err = parse_detach_args(argc, argv, &attach_type, &ifindex);
> + if (err)
> + return err;
> +
> + /* to detach xdp prog */
> + progfd = -1;
> + if (is_prefix("xdp", attach_type_strings[attach_type]))
> + err = do_attach_detach_xdp(&progfd, &attach_type, &ifindex);
Similar to previous patch, parameters no need to be pointer.
> +
> + if (err < 0) {
> + p_err("link set %s failed", attach_type_strings[attach_type]);
> + return -1;
Maybe "return err"?
> + }
> +
> + if (json_output)
> + jsonw_null(json_wtr);
> +
> + return 0;
> +}
> +
> static int do_show(int argc, char **argv)
> {
> struct bpf_attach_info attach_info = {};
> @@ -406,6 +456,7 @@ static int do_help(int argc, char **argv)
> fprintf(stderr,
> "Usage: %s %s { show | list } [dev <devname>]\n"
> " %s %s attach PROG LOAD_TYPE <devname>\n"
> + " %s %s detach LOAD_TYPE <devname>\n"
> " %s %s help\n"
> "\n"
> " " HELP_SPEC_PROGRAM "\n"
> @@ -415,7 +466,8 @@ static int do_help(int argc, char **argv)
> " to dump program attachments. For program types\n"
> " sk_{filter,skb,msg,reuseport} and lwt/seg6, please\n"
> " consult iproute2.\n",
> - bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2]);
> + bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2],
> + bin_name, argv[-2]);
>
> return 0;
> }
> @@ -424,6 +476,7 @@ static const struct cmd cmds[] = {
> { "show", do_show },
> { "list", do_show },
> { "attach", do_attach },
> + { "detach", do_detach },
> { "help", do_help },
> { 0 }
> };
> --
> 2.20.1
>
