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 | #include <bpf/libbpf.h> |
24 | |
25 | #include "bpf_insn.h" |
26 | |
27 | static int usage(const char *argv0) |
28 | { |
29 | printf(format: "Usage: %s cg-path filter-path [filter-id]\n" , argv0); |
30 | return EXIT_FAILURE; |
31 | } |
32 | |
33 | int main(int argc, char **argv) |
34 | { |
35 | int cg_fd, err, ret = EXIT_FAILURE, filter_id = 0, prog_cnt = 0; |
36 | const char *link_pin_path = "/sys/fs/bpf/test_cgrp2_sock2" ; |
37 | struct bpf_link *link = NULL; |
38 | struct bpf_program *progs[2]; |
39 | struct bpf_program *prog; |
40 | struct bpf_object *obj; |
41 | |
42 | if (argc < 3) |
43 | return usage(argv0: argv[0]); |
44 | |
45 | if (argc > 3) |
46 | filter_id = atoi(nptr: argv[3]); |
47 | |
48 | cg_fd = open(file: argv[1], O_DIRECTORY | O_RDONLY); |
49 | if (cg_fd < 0) { |
50 | printf(format: "Failed to open cgroup path: '%s'\n" , strerror(errno)); |
51 | return ret; |
52 | } |
53 | |
54 | obj = bpf_object__open_file(argv[2], NULL); |
55 | if (libbpf_get_error(obj)) { |
56 | printf(format: "ERROR: opening BPF object file failed\n" ); |
57 | return ret; |
58 | } |
59 | |
60 | bpf_object__for_each_program(prog, obj) { |
61 | progs[prog_cnt] = prog; |
62 | prog_cnt++; |
63 | } |
64 | |
65 | if (filter_id >= prog_cnt) { |
66 | printf(format: "Invalid program id; program not found in file\n" ); |
67 | goto cleanup; |
68 | } |
69 | |
70 | /* load BPF program */ |
71 | if (bpf_object__load(obj)) { |
72 | printf(format: "ERROR: loading BPF object file failed\n" ); |
73 | goto cleanup; |
74 | } |
75 | |
76 | link = bpf_program__attach_cgroup(progs[filter_id], cg_fd); |
77 | if (libbpf_get_error(link)) { |
78 | printf(format: "ERROR: bpf_program__attach failed\n" ); |
79 | link = NULL; |
80 | goto cleanup; |
81 | } |
82 | |
83 | err = bpf_link__pin(link, link_pin_path); |
84 | if (err < 0) { |
85 | printf(format: "ERROR: bpf_link__pin failed: %d\n" , err); |
86 | goto cleanup; |
87 | } |
88 | |
89 | ret = EXIT_SUCCESS; |
90 | |
91 | cleanup: |
92 | bpf_link__destroy(link); |
93 | bpf_object__close(obj); |
94 | return ret; |
95 | } |
96 | |