1 /* Copyright (c) 2016 Facebook
2  *
3  * This program is free software; you can redistribute it and/or
4  * modify it under the terms of version 2 of the GNU General Public
5  * License as published by the Free Software Foundation.
6  */
7 #include <linux/unistd.h>
8 #include <linux/bpf.h>
9 
10 #include <stdlib.h>
11 #include <stdio.h>
12 #include <unistd.h>
13 #include <string.h>
14 #include <errno.h>
15 
16 #include <bpf/bpf.h>
17 
18 static void usage(void)
19 {
20 	printf("Usage: tc_l2_ipip_redirect [...]\n");
21 	printf("       -U <file>   Update an already pinned BPF array\n");
22 	printf("       -i <ifindex> Interface index\n");
23 	printf("       -h          Display this help\n");
24 }
25 
26 int main(int argc, char **argv)
27 {
28 	const char *pinned_file = NULL;
29 	int ifindex = -1;
30 	int array_key = 0;
31 	int array_fd = -1;
32 	int ret = -1;
33 	int opt;
34 
35 	while ((opt = getopt(argc, argv, "F:U:i:")) != -1) {
36 		switch (opt) {
37 		/* General args */
38 		case 'U':
39 			pinned_file = optarg;
40 			break;
41 		case 'i':
42 			ifindex = atoi(optarg);
43 			break;
44 		default:
45 			usage();
46 			goto out;
47 		}
48 	}
49 
50 	if (ifindex < 0 || !pinned_file) {
51 		usage();
52 		goto out;
53 	}
54 
55 	array_fd = bpf_obj_get(pinned_file);
56 	if (array_fd < 0) {
57 		fprintf(stderr, "bpf_obj_get(%s): %s(%d)\n",
58 			pinned_file, strerror(errno), errno);
59 		goto out;
60 	}
61 
62 	/* bpf_tunnel_key.remote_ipv4 expects host byte orders */
63 	ret = bpf_map_update_elem(array_fd, &array_key, &ifindex, 0);
64 	if (ret) {
65 		perror("bpf_map_update_elem");
66 		goto out;
67 	}
68 
69 out:
70 	if (array_fd != -1)
71 		close(array_fd);
72 	return ret;
73 }
74