On Wed, 7 Aug 2019 10:02:04 -0700
Y Song <ys114...@gmail.com> wrote:
> On Tue, Aug 6, 2019 at 7:25 PM 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>
> > ---
> > tools/bpf/bpftool/net.c | 42 ++++++++++++++++++++++++++++++++++++++++-
> > 1 file changed, 41 insertions(+), 1 deletion(-)
> >
> > diff --git a/tools/bpf/bpftool/net.c b/tools/bpf/bpftool/net.c
> > index c05a3fac5cac..7be96acb08e0 100644
> > --- a/tools/bpf/bpftool/net.c
> > +++ b/tools/bpf/bpftool/net.c
> > @@ -343,6 +343,43 @@ 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 progfd, ifindex, err = 0;
> > +
> > + /* parse detach args */
> > + if (!REQ_ARGS(3))
> > + 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();
> > + ifindex = net_parse_dev(&argc, &argv);
> > + if (ifindex < 1)
> > + return -EINVAL;
> > +
> > + /* detach xdp prog */
> > + progfd = -1;
> > + if (is_prefix("xdp", attach_type_strings[attach_type]))
> > + err = do_attach_detach_xdp(progfd, attach_type, ifindex,
> > NULL);
>
> I found an issue here. This is probably related to do_attach_detach_xdp.
>
> -bash-4.4$ sudo ./bpftool net attach x pinned /sys/fs/bpf/xdp_example dev v1
> -bash-4.4$ sudo ./bpftool net
> xdp:
> v1(4) driver id 1172
>
> tc:
> eth0(2) clsact/ingress fbflow_icmp id 29 act []
> eth0(2) clsact/egress cls_fg_dscp_section id 27 act []
> eth0(2) clsact/egress fbflow_egress id 28
> eth0(2) clsact/egress fbflow_sslwall_egress id 35
>
> flow_dissector:
>
> -bash-4.4$ sudo ./bpftool net detach x dev v2
Shouldn't this be v1 as dev?
> -bash-4.4$ sudo ./bpftool net
> xdp:
> v1(4) driver id 1172
>
> tc:
> eth0(2) clsact/ingress fbflow_icmp id 29 act []
> eth0(2) clsact/egress cls_fg_dscp_section id 27 act []
> eth0(2) clsact/egress fbflow_egress id 28
> eth0(2) clsact/egress fbflow_sslwall_egress id 35
>
> flow_dissector:
>
> -bash-4.4$
>
> Basically detaching may fail due to wrong dev name or wrong type, etc.
> But the tool did not return an error. Is this expected?
> This may be related to this funciton "bpf_set_link_xdp_fd()".
> So this patch itself should be okay.
>
> > +
> > + if (err < 0) {
> > + p_err("interface %s detach failed",
> > + attach_type_strings[attach_type]);
> > + 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 = {};
> > @@ -419,6 +456,7 @@ static int do_help(int argc, char **argv)
> > fprintf(stderr,
> > "Usage: %s %s { show | list } [dev <devname>]\n"
> > " %s %s attach ATTACH_TYPE PROG dev <devname> [
> > overwrite ]\n"
> > + " %s %s detach ATTACH_TYPE dev <devname>\n"
> > " %s %s help\n"
> > "\n"
> > " " HELP_SPEC_PROGRAM "\n"
> > @@ -429,7 +467,8 @@ 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;
> > }
> > @@ -438,6 +477,7 @@ static const struct cmd cmds[] = {
> > { "show", do_show },
> > { "list", do_show },
> > { "attach", do_attach },
> > + { "detach", do_detach },
> > { "help", do_help },
> > { 0 }
> > };
> > --
> > 2.20.1
> >
