xdp: sample program for new bpf_redirect helper

This implements a sample program for testing bpf_redirect. It reports
the number of packets redirected per second and as input takes the
ifindex of the device to run the xdp program on and the ifindex of the
interface to redirect packets to.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Tested-by: Andy Gospodarek <andy@greyhouse.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 102 insertions, 0 deletions

diff --git a/samples/bpf/xdp_redirect_user.c b/samples/bpf/xdp_redirect_user.c
new file mode 100644
index 000000000000..761a91d5d7b4
--- /dev/null
+++ b/samples/bpf/xdp_redirect_user.c
@@ -0,0 +1,102 @@
+/* Copyright (c) 2016 John Fastabend <john.r.fastabend@intel.com>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+#include <linux/bpf.h>
+#include <assert.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "bpf_load.h"
+#include "bpf_util.h"
+#include "libbpf.h"
+
+static int ifindex_in;
+static int ifindex_out;
+
+static void int_exit(int sig)
+{
+	set_link_xdp_fd(ifindex_in, -1, 0);
+	exit(0);
+}
+
+/* simple per-protocol drop counter
+ */
+static void poll_stats(int interval, int ifindex)
+{
+	unsigned int nr_cpus = bpf_num_possible_cpus();
+	__u64 values[nr_cpus], prev[nr_cpus];
+
+	memset(prev, 0, sizeof(prev));
+
+	while (1) {
+		__u64 sum = 0;
+		__u32 key = 0;
+		int i;
+
+		sleep(interval);
+		assert(bpf_map_lookup_elem(map_fd[1], &key, values) == 0);
+		for (i = 0; i < nr_cpus; i++)
+			sum += (values[i] - prev[i]);
+		if (sum)
+			printf("ifindex %i: %10llu pkt/s\n",
+			       ifindex, sum / interval);
+		memcpy(prev, values, sizeof(values));
+	}
+}
+
+int main(int ac, char **argv)
+{
+	char filename[256];
+	int ret, key = 0;
+
+	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+
+	if (ac != 3) {
+		printf("usage: %s IFINDEX_IN IFINDEX_OUT\n", argv[0]);
+		return 1;
+	}
+
+	ifindex_in = strtoul(argv[1], NULL, 0);
+	ifindex_out = strtoul(argv[2], NULL, 0);
+
+	if (load_bpf_file(filename)) {
+		printf("%s", bpf_log_buf);
+		return 1;
+	}
+
+	if (!prog_fd[0]) {
+		printf("load_bpf_file: %s\n", strerror(errno));
+		return 1;
+	}
+
+	signal(SIGINT, int_exit);
+
+	if (set_link_xdp_fd(ifindex_in, prog_fd[0], 0) < 0) {
+		printf("link set xdp fd failed\n");
+		return 1;
+	}
+
+	/* bpf redirect port */
+	ret = bpf_map_update_elem(map_fd[0], &key, &ifindex_out, 0);
+	if (ret) {
+		perror("bpf_update_elem");
+		goto out;
+	}
+
+	poll_stats(2, ifindex_out);
+
+out:
+	return 0;
+}