1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2016 Facebook
3  */
4 #include <linux/unistd.h>
5 #include <linux/bpf.h>
6 
7 #include <stdlib.h>
8 #include <stdio.h>
9 #include <unistd.h>
10 #include <string.h>
11 #include <errno.h>
12 
13 #include <bpf/bpf.h>
14 
usage(void)15 static void usage(void)
16 {
17 	printf("Usage: tc_l2_ipip_redirect [...]\n");
18 	printf("       -U <file>   Update an already pinned BPF array\n");
19 	printf("       -i <ifindex> Interface index\n");
20 	printf("       -h          Display this help\n");
21 }
22 
main(int argc,char ** argv)23 int main(int argc, char **argv)
24 {
25 	const char *pinned_file = NULL;
26 	int ifindex = -1;
27 	int array_key = 0;
28 	int array_fd = -1;
29 	int ret = -1;
30 	int opt;
31 
32 	while ((opt = getopt(argc, argv, "F:U:i:")) != -1) {
33 		switch (opt) {
34 		/* General args */
35 		case 'U':
36 			pinned_file = optarg;
37 			break;
38 		case 'i':
39 			ifindex = atoi(optarg);
40 			break;
41 		default:
42 			usage();
43 			goto out;
44 		}
45 	}
46 
47 	if (ifindex < 0 || !pinned_file) {
48 		usage();
49 		goto out;
50 	}
51 
52 	array_fd = bpf_obj_get(pinned_file);
53 	if (array_fd < 0) {
54 		fprintf(stderr, "bpf_obj_get(%s): %s(%d)\n",
55 			pinned_file, strerror(errno), errno);
56 		goto out;
57 	}
58 
59 	/* bpf_tunnel_key.remote_ipv4 expects host byte orders */
60 	ret = bpf_map_update_elem(array_fd, &array_key, &ifindex, 0);
61 	if (ret) {
62 		perror("bpf_map_update_elem");
63 		goto out;
64 	}
65 
66 out:
67 	if (array_fd != -1)
68 		close(array_fd);
69 	return ret;
70 }
71