1 // SPDX-License-Identifier: GPL-2.0
2 /* eBPF example program:
3 *
4 * - Loads eBPF program
5 *
6 * The eBPF program loads a filter from file and attaches the
7 * program to a cgroup using BPF_PROG_ATTACH
8 */
9
10 #define _GNU_SOURCE
11
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include <stddef.h>
15 #include <string.h>
16 #include <unistd.h>
17 #include <assert.h>
18 #include <errno.h>
19 #include <fcntl.h>
20 #include <net/if.h>
21 #include <linux/bpf.h>
22 #include <bpf/bpf.h>
23
24 #include "bpf_insn.h"
25 #include "bpf_load.h"
26
usage(const char * argv0)27 static int usage(const char *argv0)
28 {
29 printf("Usage: %s cg-path filter-path [filter-id]\n", argv0);
30 return EXIT_FAILURE;
31 }
32
main(int argc,char ** argv)33 int main(int argc, char **argv)
34 {
35 int cg_fd, ret, filter_id = 0;
36
37 if (argc < 3)
38 return usage(argv[0]);
39
40 cg_fd = open(argv[1], O_DIRECTORY | O_RDONLY);
41 if (cg_fd < 0) {
42 printf("Failed to open cgroup path: '%s'\n", strerror(errno));
43 return EXIT_FAILURE;
44 }
45
46 if (load_bpf_file(argv[2]))
47 return EXIT_FAILURE;
48
49 printf("Output from kernel verifier:\n%s\n-------\n", bpf_log_buf);
50
51 if (argc > 3)
52 filter_id = atoi(argv[3]);
53
54 if (filter_id >= prog_cnt) {
55 printf("Invalid program id; program not found in file\n");
56 return EXIT_FAILURE;
57 }
58
59 ret = bpf_prog_attach(prog_fd[filter_id], cg_fd,
60 BPF_CGROUP_INET_SOCK_CREATE, 0);
61 if (ret < 0) {
62 printf("Failed to attach prog to cgroup: '%s'\n",
63 strerror(errno));
64 return EXIT_FAILURE;
65 }
66
67 return EXIT_SUCCESS;
68 }
69