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.
> + "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;
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
