tools/testing/selftests/bpf/prog_tests/cgroup_preorder.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
#include <test_progs.h>
#include "cgroup_helpers.h"
#include "cgroup_preorder.skel.h"

static int run_getsockopt_test(int cg_parent, int cg_child, int sock_fd, bool all_preorder)
{
	LIBBPF_OPTS(bpf_prog_attach_opts, opts);
	enum bpf_attach_type prog_c_atype, prog_c2_atype, prog_p_atype, prog_p2_atype;
	int prog_c_fd, prog_c2_fd, prog_p_fd, prog_p2_fd;
	struct cgroup_preorder *skel = NULL;
	struct bpf_program *prog;
	__u8 *result, buf;
	socklen_t optlen;
	int err = 0;

	skel = cgroup_preorder__open_and_load();
	if (!ASSERT_OK_PTR(skel, "cgroup_preorder__open_and_load"))
		return 0;

	buf = 0x00;
	err = setsockopt(sock_fd, SOL_IP, IP_TOS, &buf, 1);
	if (!ASSERT_OK(err, "setsockopt"))
		goto close_skel;

	opts.flags = BPF_F_ALLOW_MULTI;
	if (all_preorder)
		opts.flags |= BPF_F_PREORDER;
	prog = skel->progs.child;
	prog_c_fd = bpf_program__fd(prog);
	prog_c_atype = bpf_program__expected_attach_type(prog);
	err = bpf_prog_attach_opts(prog_c_fd, cg_child, prog_c_atype, &opts);
	if (!ASSERT_OK(err, "bpf_prog_attach_opts-child"))
		goto close_skel;

	opts.flags = BPF_F_ALLOW_MULTI | BPF_F_PREORDER;
	prog = skel->progs.child_2;
	prog_c2_fd = bpf_program__fd(prog);
	prog_c2_atype = bpf_program__expected_attach_type(prog);
	err = bpf_prog_attach_opts(prog_c2_fd, cg_child, prog_c2_atype, &opts);
	if (!ASSERT_OK(err, "bpf_prog_attach_opts-child_2"))
		goto detach_child;

	optlen = 1;
	err = getsockopt(sock_fd, SOL_IP, IP_TOS, &buf, &optlen);
	if (!ASSERT_OK(err, "getsockopt"))
		goto detach_child_2;

	result = skel->bss->result;
	if (all_preorder)
		ASSERT_TRUE(result[0] == 1 && result[1] == 2, "child only");
	else
		ASSERT_TRUE(result[0] == 2 && result[1] == 1, "child only");

	skel->bss->idx = 0;
	memset(result, 0, 4);

	opts.flags = BPF_F_ALLOW_MULTI;
	if (all_preorder)
		opts.flags |= BPF_F_PREORDER;
	prog = skel->progs.parent;
	prog_p_fd = bpf_program__fd(prog);
	prog_p_atype = bpf_program__expected_attach_type(prog);
	err = bpf_prog_attach_opts(prog_p_fd, cg_parent, prog_p_atype, &opts);
	if (!ASSERT_OK(err, "bpf_prog_attach_opts-parent"))
		goto detach_child_2;

	opts.flags = BPF_F_ALLOW_MULTI | BPF_F_PREORDER;
	prog = skel->progs.parent_2;
	prog_p2_fd = bpf_program__fd(prog);
	prog_p2_atype = bpf_program__expected_attach_type(prog);
	err = bpf_prog_attach_opts(prog_p2_fd, cg_parent, prog_p2_atype, &opts);
	if (!ASSERT_OK(err, "bpf_prog_attach_opts-parent_2"))
		goto detach_parent;

	err = getsockopt(sock_fd, SOL_IP, IP_TOS, &buf, &optlen);
	if (!ASSERT_OK(err, "getsockopt"))
		goto detach_parent_2;

	if (all_preorder)
		ASSERT_TRUE(result[0] == 3 && result[1] == 4 && result[2] == 1 && result[3] == 2,
			    "parent and child");
	else
		ASSERT_TRUE(result[0] == 4 && result[1] == 2 && result[2] == 1 && result[3] == 3,
			    "parent and child");

detach_parent_2:
	ASSERT_OK(bpf_prog_detach2(prog_p2_fd, cg_parent, prog_p2_atype),
		  "bpf_prog_detach2-parent_2");
detach_parent:
	ASSERT_OK(bpf_prog_detach2(prog_p_fd, cg_parent, prog_p_atype),
		  "bpf_prog_detach2-parent");
detach_child_2:
	ASSERT_OK(bpf_prog_detach2(prog_c2_fd, cg_child, prog_c2_atype),
		  "bpf_prog_detach2-child_2");
detach_child:
	ASSERT_OK(bpf_prog_detach2(prog_c_fd, cg_child, prog_c_atype),
		  "bpf_prog_detach2-child");
close_skel:
	cgroup_preorder__destroy(skel);
	return err;
}

void test_cgroup_preorder(void)
{
	int cg_parent = -1, cg_child = -1, sock_fd = -1;

	cg_parent = test__join_cgroup("/parent");
	if (!ASSERT_GE(cg_parent, 0, "join_cgroup /parent"))
		goto out;

	cg_child = test__join_cgroup("/parent/child");
	if (!ASSERT_GE(cg_child, 0, "join_cgroup /parent/child"))
		goto out;

	sock_fd = socket(AF_INET, SOCK_STREAM, 0);
	if (!ASSERT_GE(sock_fd, 0, "socket"))
		goto out;

	ASSERT_OK(run_getsockopt_test(cg_parent, cg_child, sock_fd, false), "getsockopt_test_1");
	ASSERT_OK(run_getsockopt_test(cg_parent, cg_child, sock_fd, true), "getsockopt_test_2");

out:
	close(sock_fd);
	close(cg_child);
	close(cg_parent);
}