// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
#include <test_progs.h>
#include <time.h>
#include <sys/epoll.h>
#include "struct_ops_module.skel.h"
#include "struct_ops_nulled_out_cb.skel.h"
#include "struct_ops_forgotten_cb.skel.h"
#include "struct_ops_detach.skel.h"
static void check_map_info(struct bpf_map_info *info)
{
struct bpf_btf_info btf_info;
char btf_name[256];
u32 btf_info_len = sizeof(btf_info);
int err, fd;
fd = bpf_btf_get_fd_by_id(info->btf_vmlinux_id);
if (!ASSERT_GE(fd, 0, "get_value_type_btf_obj_fd"))
return;
memset(&btf_info, 0, sizeof(btf_info));
btf_info.name = ptr_to_u64(btf_name);
btf_info.name_len = sizeof(btf_name);
err = bpf_btf_get_info_by_fd(fd, &btf_info, &btf_info_len);
if (!ASSERT_OK(err, "get_value_type_btf_obj_info"))
goto cleanup;
if (!ASSERT_EQ(strcmp(btf_name, "bpf_testmod"), 0, "get_value_type_btf_obj_name"))
goto cleanup;
cleanup:
close(fd);
}
static int attach_ops_and_check(struct struct_ops_module *skel,
struct bpf_map *map,
int expected_test_2_result)
{
struct bpf_link *link;
link = bpf_map__attach_struct_ops(map);
ASSERT_OK_PTR(link, "attach_test_mod_1");
if (!link)
return -1;
/* test_{1,2}() would be called from bpf_dummy_reg() in bpf_testmod.c */
ASSERT_EQ(skel->bss->test_1_result, 0xdeadbeef, "test_1_result");
ASSERT_EQ(skel->bss->test_2_result, expected_test_2_result, "test_2_result");
bpf_link__destroy(link);
return 0;
}
static void test_struct_ops_load(void)
{
struct struct_ops_module *skel;
struct bpf_map_info info = {};
int err;
u32 len;
skel = struct_ops_module__open();
if (!ASSERT_OK_PTR(skel, "struct_ops_module_open"))
return;
skel->struct_ops.testmod_1->data = 13;
skel->struct_ops.testmod_1->test_2 = skel->progs.test_3;
/* Since test_2() is not being used, it should be disabled from
* auto-loading, or it will fail to load.
*/
bpf_program__set_autoload(skel->progs.test_2, false);
bpf_map__set_autocreate(skel->maps.testmod_zeroed, false);
err = struct_ops_module__load(skel);
if (!ASSERT_OK(err, "struct_ops_module_load"))
goto cleanup;
len = sizeof(info);
err = bpf_map_get_info_by_fd(bpf_map__fd(skel->maps.testmod_1), &info,
&len);
if (!ASSERT_OK(err, "bpf_map_get_info_by_fd"))
goto cleanup;
check_map_info(&info);
/* test_3() will be called from bpf_dummy_reg() in bpf_testmod.c
*
* In bpf_testmod.c it will pass 4 and 13 (the value of data) to
* .test_2. So, the value of test_2_result should be 20 (4 + 13 +
* 3).
*/
if (!attach_ops_and_check(skel, skel->maps.testmod_1, 20))
goto cleanup;
if (!attach_ops_and_check(skel, skel->maps.testmod_2, 12))
goto cleanup;
cleanup:
struct_ops_module__destroy(skel);
}
static void test_struct_ops_not_zeroed(void)
{
struct struct_ops_module *skel;
int err;
/* zeroed is 0, and zeroed_op is null */
skel = struct_ops_module__open();
if (!ASSERT_OK_PTR(skel, "struct_ops_module_open"))
return;
skel->struct_ops.testmod_zeroed->zeroed = 0;
/* zeroed_op prog should be not loaded automatically now */
skel->struct_ops.testmod_zeroed->zeroed_op = NULL;
err = struct_ops_module__load(skel);
ASSERT_OK(err, "struct_ops_module_load");
struct_ops_module__destroy(skel);
/* zeroed is not 0 */
skel = struct_ops_module__open();
if (!ASSERT_OK_PTR(skel, "struct_ops_module_open_not_zeroed"))
return;
/* libbpf should reject the testmod_zeroed since struct
* bpf_testmod_ops in the kernel has no "zeroed" field and the
* value of "zeroed" is non-zero.
*/
skel->struct_ops.testmod_zeroed->zeroed = 0xdeadbeef;
skel->struct_ops.testmod_zeroed->zeroed_op = NULL;
err = struct_ops_module__load(skel);
ASSERT_ERR(err, "struct_ops_module_load_not_zeroed");
struct_ops_module__destroy(skel);
/* zeroed_op is not null */
skel = struct_ops_module__open();
if (!ASSERT_OK_PTR(skel, "struct_ops_module_open_not_zeroed_op"))
return;
/* libbpf should reject the testmod_zeroed since the value of its
* "zeroed_op" is not null.
*/
skel->struct_ops.testmod_zeroed->zeroed_op = skel->progs.test_3;
err = struct_ops_module__load(skel);
ASSERT_ERR(err, "struct_ops_module_load_not_zeroed_op");
struct_ops_module__destroy(skel);
}
/* The signature of an implementation might not match the signature of the
* function pointer prototype defined in the BPF program. This mismatch
* should be allowed as long as the behavior of the operator program
* adheres to the signature in the kernel. Libbpf should not enforce the
* signature; rather, let the kernel verifier handle the enforcement.
*/
static void test_struct_ops_incompatible(void)
{
struct struct_ops_module *skel;
struct bpf_link *link;
int err;
skel = struct_ops_module__open();
if (!ASSERT_OK_PTR(skel, "struct_ops_module_open"))
return;
bpf_map__set_autocreate(skel->maps.testmod_zeroed, false);
err = struct_ops_module__load(skel);
if (!ASSERT_OK(err, "skel_load"))
goto cleanup;
link = bpf_map__attach_struct_ops(skel->maps.testmod_incompatible);
if (ASSERT_OK_PTR(link, "attach_struct_ops"))
bpf_link__destroy(link);
cleanup:
struct_ops_module__destroy(skel);
}
/* validate that it's ok to "turn off" callback that kernel supports */
static void test_struct_ops_nulled_out_cb(void)
{
struct struct_ops_nulled_out_cb *skel;
int err;
skel = struct_ops_nulled_out_cb__open();
if (!ASSERT_OK_PTR(skel, "skel_open"))
return;
/* kernel knows about test_1, but we still null it out */
skel->struct_ops.ops->test_1 = NULL;
err = struct_ops_nulled_out_cb__load(skel);
if (!ASSERT_OK(err, "skel_load"))
goto cleanup;
ASSERT_FALSE(bpf_program__autoload(skel->progs.test_1_turn_off), "prog_autoload");
ASSERT_LT(bpf_program__fd(skel->progs.test_1_turn_off), 0, "prog_fd");
cleanup:
struct_ops_nulled_out_cb__destroy(skel);
}
/* validate that libbpf generates reasonable error message if struct_ops is
* not referenced in any struct_ops map
*/
static void test_struct_ops_forgotten_cb(void)
{
struct struct_ops_forgotten_cb *skel;
char *log;
int err;
skel = struct_ops_forgotten_cb__open();
if (!ASSERT_OK_PTR(skel, "skel_open"))
return;
start_libbpf_log_capture();
err = struct_ops_forgotten_cb__load(skel);
if (!ASSERT_ERR(err, "skel_load"))
goto cleanup;
log = stop_libbpf_log_capture();
ASSERT_HAS_SUBSTR(log,
"prog 'test_1_forgotten': SEC(\"struct_ops\") program isn't referenced anywhere, did you forget to use it?",
"libbpf_log");
free(log);
struct_ops_forgotten_cb__destroy(skel);
/* now let's programmatically use it, we should be fine now */
skel = struct_ops_forgotten_cb__open();
if (!ASSERT_OK_PTR(skel, "skel_open"))
return;
skel->struct_ops.ops->test_1 = skel->progs.test_1_forgotten; /* not anymore */
err = struct_ops_forgotten_cb__load(skel);
if (!ASSERT_OK(err, "skel_load"))
goto cleanup;
cleanup:
struct_ops_forgotten_cb__destroy(skel);
}
/* Detach a link from a user space program */
static void test_detach_link(void)
{
struct epoll_event ev, events[2];
struct struct_ops_detach *skel;
struct bpf_link *link = NULL;
int fd, epollfd = -1, nfds;
int err;
skel = struct_ops_detach__open_and_load();
if (!ASSERT_OK_PTR(skel, "struct_ops_detach__open_and_load"))
return;
link = bpf_map__attach_struct_ops(skel->maps.testmod_do_detach);
if (!ASSERT_OK_PTR(link, "attach_struct_ops"))
goto cleanup;
fd = bpf_link__fd(link);
if (!ASSERT_GE(fd, 0, "link_fd"))
goto cleanup;
epollfd = epoll_create1(0);
if (!ASSERT_GE(epollfd, 0, "epoll_create1"))
goto cleanup;
ev.events = EPOLLHUP;
ev.data.fd = fd;
err = epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &ev);
if (!ASSERT_OK(err, "epoll_ctl"))
goto cleanup;
err = bpf_link__detach(link);
if (!ASSERT_OK(err, "detach_link"))
goto cleanup;
/* Wait for EPOLLHUP */
nfds = epoll_wait(epollfd, events, 2, 500);
if (!ASSERT_EQ(nfds, 1, "epoll_wait"))
goto cleanup;
if (!ASSERT_EQ(events[0].data.fd, fd, "epoll_wait_fd"))
goto cleanup;
if (!ASSERT_TRUE(events[0].events & EPOLLHUP, "events[0].events"))
goto cleanup;
cleanup:
if (epollfd >= 0)
close(epollfd);
bpf_link__destroy(link);
struct_ops_detach__destroy(skel);
}
void serial_test_struct_ops_module(void)
{
if (test__start_subtest("struct_ops_load"))
test_struct_ops_load();
if (test__start_subtest("struct_ops_not_zeroed"))
test_struct_ops_not_zeroed();
if (test__start_subtest("struct_ops_incompatible"))
test_struct_ops_incompatible();
if (test__start_subtest("struct_ops_null_out_cb"))
test_struct_ops_nulled_out_cb();
if (test__start_subtest("struct_ops_forgotten_cb"))
test_struct_ops_forgotten_cb();
if (test__start_subtest("test_detach_link"))
test_detach_link();
}
Codebase Browser
linux