On Fri, 25 Jan 2019 09:38:22 +0100
Jesper Dangaard Brouer <bro...@redhat.com> wrote:
> On Thu, 24 Jan 2019 22:47:45 +0100
> Maciej Fijalkowski <maciejromanfijalkow...@gmail.com> wrote:
>
> > diff --git a/samples/bpf/xdp_sample_pkts_user.c
> > b/samples/bpf/xdp_sample_pkts_user.c index 5f5828ee0761..362ad35b524d 100644
> > --- a/samples/bpf/xdp_sample_pkts_user.c
> > +++ b/samples/bpf/xdp_sample_pkts_user.c
> > @@ -13,6 +13,8 @@
> > #include <libbpf.h>
> > #include <bpf/bpf.h>
> > #include <sys/resource.h>
> > +#include <libgen.h>
> > +#include <linux/if_link.h>
> >
> > #include "perf-sys.h"
> > #include "trace_helpers.h"
> > @@ -21,12 +23,13 @@
> > static int pmu_fds[MAX_CPUS], if_idx;
> > static struct perf_event_mmap_page *headers[MAX_CPUS];
> > static char *if_name;
> > +static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
> >
> > static int do_attach(int idx, int fd, const char *name)
> > {
> > int err;
> >
> > - err = bpf_set_link_xdp_fd(idx, fd, 0);
> > + err = bpf_set_link_xdp_fd(idx, fd, xdp_flags);
> > if (err < 0)
> > printf("ERROR: failed to attach program to %s\n", name);
> >
> > @@ -98,21 +101,42 @@ static void sig_handler(int signo)
> > exit(0);
> > }
> >
> > +static void usage(const char *prog)
> > +{
> > + fprintf(stderr,
> > + "%s: %s [OPTS] IFINDEX\n\n"
> ^^^^^^^
> The usage help text is wrong, this sample takes the interface name as input.
>
It can take ifindex as well as ifname actually as you're saying later in this
mail - so I'm going to fix this message to "(...) IFNAME/IFINDEX" in v4.
Hope that makes sense?
>
> > + "OPTS:\n"
> > + " -F force loading prog\n",
> > + __func__, prog);
> > +}
> > +
> > int main(int argc, char **argv)
> > {
> > struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
> > struct bpf_prog_load_attr prog_load_attr = {
> > .prog_type = BPF_PROG_TYPE_XDP,
> > };
> > + const char *optstr = "F";
> > + int prog_fd, map_fd, opt;
> > struct bpf_object *obj;
> > struct bpf_map *map;
> > - int prog_fd, map_fd;
> > char filename[256];
> > int ret, err, i;
> > int numcpus;
> >
> > - if (argc < 2) {
> > - printf("Usage: %s <ifname>\n", argv[0]);
> ^^^^^^^^
> Old help text says <ifname>
>
> > + while ((opt = getopt(argc, argv, optstr)) != -1) {
> > + switch (opt) {
> > + case 'F':
> > + xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
> > + break;
> > + default:
> > + usage(basename(argv[0]));
> > + return 1;
> > + }
> > + }
> > +
> > + if (optind == argc) {
> > + usage(basename(argv[0]));
> > return 1;
> > }
> >
> > @@ -143,16 +167,16 @@ int main(int argc, char **argv)
> > }
> > map_fd = bpf_map__fd(map);
> >
> > - if_idx = if_nametoindex(argv[1]);
> > + if_idx = if_nametoindex(argv[optind]);
>
> The we convert the ifname to ifindex.
>
> > if (!if_idx)
> > - if_idx = strtoul(argv[1], NULL, 0);
> > + if_idx = strtoul(argv[optind], NULL, 0);
> >
>
> We do support falling back to using this as an ifindex.
>
>
> > if (!if_idx) {
> > fprintf(stderr, "Invalid ifname\n");
> > return 1;
> > }
> > - if_name = argv[1];
> > - err = do_attach(if_idx, prog_fd, argv[1]);
> > + if_name = argv[optind];
> > + err = do_attach(if_idx, prog_fd, if_name);
> > if (err)
> > return err;
>
>
