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1// SPDX-License-Identifier: GPL-2.02/* eBPF example program:3 *4 * - Loads eBPF program5 *6 * The eBPF program loads a filter from file and attaches the7 * program to a cgroup using BPF_PROG_ATTACH8 */9 10#define _GNU_SOURCE11 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 27static int usage(const char *argv0)28{29 printf("Usage: %s cg-path filter-path [filter-id]\n", argv0);30 return EXIT_FAILURE;31}32 33int 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(argv[0]);44 45 if (argc > 3)46 filter_id = atoi(argv[3]);47 48 cg_fd = open(argv[1], O_DIRECTORY | O_RDONLY);49 if (cg_fd < 0) {50 printf("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("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("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("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("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("ERROR: bpf_link__pin failed: %d\n", err);86 goto cleanup;87 }88 89 ret = EXIT_SUCCESS;90 91cleanup:92 bpf_link__destroy(link);93 bpf_object__close(obj);94 return ret;95}96