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authorDavid Ahern <dsahern@gmail.com>2018-05-09 20:34:27 -0700
committerDaniel Borkmann <daniel@iogearbox.net>2018-05-11 00:10:57 +0200
commitfe616055f78457a0b78e0d3693d1ae26f2d7dab3 (patch)
tree2bab4dd9bff8b85508549c97886d92d82d7c22e1 /samples/bpf/xdp_fwd_user.c
parent87f5fc7e48dd3175b30dd03b41564e1a8e136323 (diff)
samples/bpf: Add example of ipv4 and ipv6 forwarding in XDP
Simple example of fast-path forwarding. It has a serious flaw in not verifying the egress device index supports XDP forwarding. If the egress device does not packets are dropped. Take this only as a simple example of fast-path forwarding. Signed-off-by: David Ahern <dsahern@gmail.com> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'samples/bpf/xdp_fwd_user.c')
-rw-r--r--samples/bpf/xdp_fwd_user.c136
1 files changed, 136 insertions, 0 deletions
diff --git a/samples/bpf/xdp_fwd_user.c b/samples/bpf/xdp_fwd_user.c
new file mode 100644
index 000000000000..9c6606f57126
--- /dev/null
+++ b/samples/bpf/xdp_fwd_user.c
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2017-18 David Ahern <dsahern@gmail.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 <linux/if_link.h>
+#include <linux/limits.h>
+#include <net/if.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <libgen.h>
+
+#include "bpf_load.h"
+#include "bpf_util.h"
+#include "libbpf.h"
+
+
+static int do_attach(int idx, int fd, const char *name)
+{
+ int err;
+
+ err = bpf_set_link_xdp_fd(idx, fd, 0);
+ if (err < 0)
+ printf("ERROR: failed to attach program to %s\n", name);
+
+ return err;
+}
+
+static int do_detach(int idx, const char *name)
+{
+ int err;
+
+ err = bpf_set_link_xdp_fd(idx, -1, 0);
+ if (err < 0)
+ printf("ERROR: failed to detach program from %s\n", name);
+
+ return err;
+}
+
+static void usage(const char *prog)
+{
+ fprintf(stderr,
+ "usage: %s [OPTS] interface-list\n"
+ "\nOPTS:\n"
+ " -d detach program\n"
+ " -D direct table lookups (skip fib rules)\n",
+ prog);
+}
+
+int main(int argc, char **argv)
+{
+ char filename[PATH_MAX];
+ int opt, i, idx, err;
+ int prog_id = 0;
+ int attach = 1;
+ int ret = 0;
+
+ while ((opt = getopt(argc, argv, ":dD")) != -1) {
+ switch (opt) {
+ case 'd':
+ attach = 0;
+ break;
+ case 'D':
+ prog_id = 1;
+ break;
+ default:
+ usage(basename(argv[0]));
+ return 1;
+ }
+ }
+
+ if (optind == argc) {
+ usage(basename(argv[0]));
+ return 1;
+ }
+
+ if (attach) {
+ snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+
+ if (access(filename, O_RDONLY) < 0) {
+ printf("error accessing file %s: %s\n",
+ filename, strerror(errno));
+ return 1;
+ }
+
+ if (load_bpf_file(filename)) {
+ printf("%s", bpf_log_buf);
+ return 1;
+ }
+
+ if (!prog_fd[prog_id]) {
+ printf("load_bpf_file: %s\n", strerror(errno));
+ return 1;
+ }
+ }
+ if (attach) {
+ for (i = 1; i < 64; ++i)
+ bpf_map_update_elem(map_fd[0], &i, &i, 0);
+ }
+
+ for (i = optind; i < argc; ++i) {
+ idx = if_nametoindex(argv[i]);
+ if (!idx)
+ idx = strtoul(argv[i], NULL, 0);
+
+ if (!idx) {
+ fprintf(stderr, "Invalid arg\n");
+ return 1;
+ }
+ if (!attach) {
+ err = do_detach(idx, argv[i]);
+ if (err)
+ ret = err;
+ } else {
+ err = do_attach(idx, prog_fd[prog_id], argv[i]);
+ if (err)
+ ret = err;
+ }
+ }
+
+ return ret;
+}