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// 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;
}
/*
* Replacing a link's program (bpf_link_update) must target the correct slot in
* the effective array even when a BPF_F_PREORDER program is attached to the
* same cgroup. All programs here are attached to a single cgroup; "parent" is
* reused only as a third distinct program.
*
* Attach child(1) normally and child_2(2) with BPF_F_PREORDER, so the effective
* order is [2, 1]. Then replace child(1)'s program with parent(3): only the
* non-preorder slot changes, giving [2, 3].
*/
static int run_link_replace_test(int cgroup_fd, int sock_fd)
{
LIBBPF_OPTS(bpf_link_create_opts, create_opts);
int err = 0, normal_link = -1, preorder_link = -1;
struct cgroup_preorder *skel = NULL;
enum bpf_attach_type atype;
__u8 *result, buf = 0x00;
socklen_t optlen = 1;
skel = cgroup_preorder__open_and_load();
if (!ASSERT_OK_PTR(skel, "cgroup_preorder__open_and_load"))
return -1;
err = setsockopt(sock_fd, SOL_IP, IP_TOS, &buf, 1);
if (!ASSERT_OK(err, "setsockopt"))
goto close_skel;
atype = bpf_program__expected_attach_type(skel->progs.child);
create_opts.flags = 0;
normal_link = bpf_link_create(bpf_program__fd(skel->progs.child),
cgroup_fd, atype, &create_opts);
if (!ASSERT_GE(normal_link, 0, "create_normal_link")) {
err = normal_link;
goto close_skel;
}
create_opts.flags = BPF_F_PREORDER;
preorder_link = bpf_link_create(bpf_program__fd(skel->progs.child_2),
cgroup_fd, atype, &create_opts);
if (!ASSERT_GE(preorder_link, 0, "create_preorder_link")) {
err = preorder_link;
goto close_links;
}
result = skel->bss->result;
skel->bss->idx = 0;
memset(result, 0, 4);
err = getsockopt(sock_fd, SOL_IP, IP_TOS, &buf, &optlen);
if (!ASSERT_OK(err, "getsockopt-before"))
goto close_links;
ASSERT_TRUE(result[0] == 2 && result[1] == 1, "order before update");
/* Replace the normal link's program child(1) -> parent(3). */
err = bpf_link_update(normal_link, bpf_program__fd(skel->progs.parent), NULL);
if (!ASSERT_OK(err, "bpf_link_update"))
goto close_links;
skel->bss->idx = 0;
memset(result, 0, 4);
err = getsockopt(sock_fd, SOL_IP, IP_TOS, &buf, &optlen);
if (!ASSERT_OK(err, "getsockopt-after"))
goto close_links;
ASSERT_TRUE(result[0] == 2 && result[1] == 3, "order after update");
close_links:
if (preorder_link >= 0)
close(preorder_link);
close(normal_link);
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");
ASSERT_OK(run_link_replace_test(cg_child, sock_fd), "link_replace_test");
out:
close(sock_fd);
close(cg_child);
close(cg_parent);
}
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