v4.19.13 snapshot.
diff --git a/samples/bpf/xdp1_user.c b/samples/bpf/xdp1_user.c
new file mode 100644
index 0000000..b02c531
--- /dev/null
+++ b/samples/bpf/xdp1_user.c
@@ -0,0 +1,138 @@
+/* Copyright (c) 2016 PLUMgrid
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#include <linux/bpf.h>
+#include <linux/if_link.h>
+#include <assert.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <libgen.h>
+#include <sys/resource.h>
+
+#include "bpf_util.h"
+#include "bpf/bpf.h"
+#include "bpf/libbpf.h"
+
+static int ifindex;
+static __u32 xdp_flags;
+
+static void int_exit(int sig)
+{
+ bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
+ exit(0);
+}
+
+/* simple per-protocol drop counter
+ */
+static void poll_stats(int map_fd, int interval)
+{
+ unsigned int nr_cpus = bpf_num_possible_cpus();
+ const unsigned int nr_keys = 256;
+ __u64 values[nr_cpus], prev[nr_keys][nr_cpus];
+ __u32 key;
+ int i;
+
+ memset(prev, 0, sizeof(prev));
+
+ while (1) {
+ sleep(interval);
+
+ for (key = 0; key < nr_keys; key++) {
+ __u64 sum = 0;
+
+ assert(bpf_map_lookup_elem(map_fd, &key, values) == 0);
+ for (i = 0; i < nr_cpus; i++)
+ sum += (values[i] - prev[key][i]);
+ if (sum)
+ printf("proto %u: %10llu pkt/s\n",
+ key, sum / interval);
+ memcpy(prev[key], values, sizeof(values));
+ }
+ }
+}
+
+static void usage(const char *prog)
+{
+ fprintf(stderr,
+ "usage: %s [OPTS] IFINDEX\n\n"
+ "OPTS:\n"
+ " -S use skb-mode\n"
+ " -N enforce native mode\n",
+ 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 = "SN";
+ int prog_fd, map_fd, opt;
+ struct bpf_object *obj;
+ struct bpf_map *map;
+ char filename[256];
+
+ while ((opt = getopt(argc, argv, optstr)) != -1) {
+ switch (opt) {
+ case 'S':
+ xdp_flags |= XDP_FLAGS_SKB_MODE;
+ break;
+ case 'N':
+ xdp_flags |= XDP_FLAGS_DRV_MODE;
+ break;
+ default:
+ usage(basename(argv[0]));
+ return 1;
+ }
+ }
+
+ if (optind == argc) {
+ usage(basename(argv[0]));
+ return 1;
+ }
+
+ if (setrlimit(RLIMIT_MEMLOCK, &r)) {
+ perror("setrlimit(RLIMIT_MEMLOCK)");
+ return 1;
+ }
+
+ ifindex = strtoul(argv[optind], NULL, 0);
+
+ snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+ prog_load_attr.file = filename;
+
+ if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
+ return 1;
+
+ map = bpf_map__next(NULL, obj);
+ if (!map) {
+ printf("finding a map in obj file failed\n");
+ return 1;
+ }
+ map_fd = bpf_map__fd(map);
+
+ if (!prog_fd) {
+ printf("load_bpf_file: %s\n", strerror(errno));
+ return 1;
+ }
+
+ signal(SIGINT, int_exit);
+ signal(SIGTERM, int_exit);
+
+ if (bpf_set_link_xdp_fd(ifindex, prog_fd, xdp_flags) < 0) {
+ printf("link set xdp fd failed\n");
+ return 1;
+ }
+
+ poll_stats(map_fd, 2);
+
+ return 0;
+}