1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
3 #include <test_progs.h>
4 #include "cgroup_helpers.h"
5 #include "cgroup_preorder.skel.h"
6
run_getsockopt_test(int cg_parent,int cg_child,int sock_fd,bool all_preorder)7 static int run_getsockopt_test(int cg_parent, int cg_child, int sock_fd, bool all_preorder)
8 {
9 LIBBPF_OPTS(bpf_prog_attach_opts, opts);
10 enum bpf_attach_type prog_c_atype, prog_c2_atype, prog_p_atype, prog_p2_atype;
11 int prog_c_fd, prog_c2_fd, prog_p_fd, prog_p2_fd;
12 struct cgroup_preorder *skel = NULL;
13 struct bpf_program *prog;
14 __u8 *result, buf;
15 socklen_t optlen;
16 int err = 0;
17
18 skel = cgroup_preorder__open_and_load();
19 if (!ASSERT_OK_PTR(skel, "cgroup_preorder__open_and_load"))
20 return 0;
21
22 buf = 0x00;
23 err = setsockopt(sock_fd, SOL_IP, IP_TOS, &buf, 1);
24 if (!ASSERT_OK(err, "setsockopt"))
25 goto close_skel;
26
27 opts.flags = BPF_F_ALLOW_MULTI;
28 if (all_preorder)
29 opts.flags |= BPF_F_PREORDER;
30 prog = skel->progs.child;
31 prog_c_fd = bpf_program__fd(prog);
32 prog_c_atype = bpf_program__expected_attach_type(prog);
33 err = bpf_prog_attach_opts(prog_c_fd, cg_child, prog_c_atype, &opts);
34 if (!ASSERT_OK(err, "bpf_prog_attach_opts-child"))
35 goto close_skel;
36
37 opts.flags = BPF_F_ALLOW_MULTI | BPF_F_PREORDER;
38 prog = skel->progs.child_2;
39 prog_c2_fd = bpf_program__fd(prog);
40 prog_c2_atype = bpf_program__expected_attach_type(prog);
41 err = bpf_prog_attach_opts(prog_c2_fd, cg_child, prog_c2_atype, &opts);
42 if (!ASSERT_OK(err, "bpf_prog_attach_opts-child_2"))
43 goto detach_child;
44
45 optlen = 1;
46 err = getsockopt(sock_fd, SOL_IP, IP_TOS, &buf, &optlen);
47 if (!ASSERT_OK(err, "getsockopt"))
48 goto detach_child_2;
49
50 result = skel->bss->result;
51 if (all_preorder)
52 ASSERT_TRUE(result[0] == 1 && result[1] == 2, "child only");
53 else
54 ASSERT_TRUE(result[0] == 2 && result[1] == 1, "child only");
55
56 skel->bss->idx = 0;
57 memset(result, 0, 4);
58
59 opts.flags = BPF_F_ALLOW_MULTI;
60 if (all_preorder)
61 opts.flags |= BPF_F_PREORDER;
62 prog = skel->progs.parent;
63 prog_p_fd = bpf_program__fd(prog);
64 prog_p_atype = bpf_program__expected_attach_type(prog);
65 err = bpf_prog_attach_opts(prog_p_fd, cg_parent, prog_p_atype, &opts);
66 if (!ASSERT_OK(err, "bpf_prog_attach_opts-parent"))
67 goto detach_child_2;
68
69 opts.flags = BPF_F_ALLOW_MULTI | BPF_F_PREORDER;
70 prog = skel->progs.parent_2;
71 prog_p2_fd = bpf_program__fd(prog);
72 prog_p2_atype = bpf_program__expected_attach_type(prog);
73 err = bpf_prog_attach_opts(prog_p2_fd, cg_parent, prog_p2_atype, &opts);
74 if (!ASSERT_OK(err, "bpf_prog_attach_opts-parent_2"))
75 goto detach_parent;
76
77 err = getsockopt(sock_fd, SOL_IP, IP_TOS, &buf, &optlen);
78 if (!ASSERT_OK(err, "getsockopt"))
79 goto detach_parent_2;
80
81 if (all_preorder)
82 ASSERT_TRUE(result[0] == 3 && result[1] == 4 && result[2] == 1 && result[3] == 2,
83 "parent and child");
84 else
85 ASSERT_TRUE(result[0] == 4 && result[1] == 2 && result[2] == 1 && result[3] == 3,
86 "parent and child");
87
88 detach_parent_2:
89 ASSERT_OK(bpf_prog_detach2(prog_p2_fd, cg_parent, prog_p2_atype),
90 "bpf_prog_detach2-parent_2");
91 detach_parent:
92 ASSERT_OK(bpf_prog_detach2(prog_p_fd, cg_parent, prog_p_atype),
93 "bpf_prog_detach2-parent");
94 detach_child_2:
95 ASSERT_OK(bpf_prog_detach2(prog_c2_fd, cg_child, prog_c2_atype),
96 "bpf_prog_detach2-child_2");
97 detach_child:
98 ASSERT_OK(bpf_prog_detach2(prog_c_fd, cg_child, prog_c_atype),
99 "bpf_prog_detach2-child");
100 close_skel:
101 cgroup_preorder__destroy(skel);
102 return err;
103 }
104
105 /*
106 * Replacing a link's program (bpf_link_update) must target the correct slot in
107 * the effective array even when a BPF_F_PREORDER program is attached to the
108 * same cgroup. All programs here are attached to a single cgroup; "parent" is
109 * reused only as a third distinct program.
110 *
111 * Attach child(1) normally and child_2(2) with BPF_F_PREORDER, so the effective
112 * order is [2, 1]. Then replace child(1)'s program with parent(3): only the
113 * non-preorder slot changes, giving [2, 3].
114 */
run_link_replace_test(int cgroup_fd,int sock_fd)115 static int run_link_replace_test(int cgroup_fd, int sock_fd)
116 {
117 LIBBPF_OPTS(bpf_link_create_opts, create_opts);
118 int err = 0, normal_link = -1, preorder_link = -1;
119 struct cgroup_preorder *skel = NULL;
120 enum bpf_attach_type atype;
121 __u8 *result, buf = 0x00;
122 socklen_t optlen = 1;
123
124 skel = cgroup_preorder__open_and_load();
125 if (!ASSERT_OK_PTR(skel, "cgroup_preorder__open_and_load"))
126 return -1;
127
128 err = setsockopt(sock_fd, SOL_IP, IP_TOS, &buf, 1);
129 if (!ASSERT_OK(err, "setsockopt"))
130 goto close_skel;
131
132 atype = bpf_program__expected_attach_type(skel->progs.child);
133
134 create_opts.flags = 0;
135 normal_link = bpf_link_create(bpf_program__fd(skel->progs.child),
136 cgroup_fd, atype, &create_opts);
137 if (!ASSERT_GE(normal_link, 0, "create_normal_link")) {
138 err = normal_link;
139 goto close_skel;
140 }
141
142 create_opts.flags = BPF_F_PREORDER;
143 preorder_link = bpf_link_create(bpf_program__fd(skel->progs.child_2),
144 cgroup_fd, atype, &create_opts);
145 if (!ASSERT_GE(preorder_link, 0, "create_preorder_link")) {
146 err = preorder_link;
147 goto close_links;
148 }
149
150 result = skel->bss->result;
151 skel->bss->idx = 0;
152 memset(result, 0, 4);
153
154 err = getsockopt(sock_fd, SOL_IP, IP_TOS, &buf, &optlen);
155 if (!ASSERT_OK(err, "getsockopt-before"))
156 goto close_links;
157 ASSERT_TRUE(result[0] == 2 && result[1] == 1, "order before update");
158
159 /* Replace the normal link's program child(1) -> parent(3). */
160 err = bpf_link_update(normal_link, bpf_program__fd(skel->progs.parent), NULL);
161 if (!ASSERT_OK(err, "bpf_link_update"))
162 goto close_links;
163
164 skel->bss->idx = 0;
165 memset(result, 0, 4);
166
167 err = getsockopt(sock_fd, SOL_IP, IP_TOS, &buf, &optlen);
168 if (!ASSERT_OK(err, "getsockopt-after"))
169 goto close_links;
170 ASSERT_TRUE(result[0] == 2 && result[1] == 3, "order after update");
171
172 close_links:
173 if (preorder_link >= 0)
174 close(preorder_link);
175 close(normal_link);
176 close_skel:
177 cgroup_preorder__destroy(skel);
178 return err;
179 }
180
test_cgroup_preorder(void)181 void test_cgroup_preorder(void)
182 {
183 int cg_parent = -1, cg_child = -1, sock_fd = -1;
184
185 cg_parent = test__join_cgroup("/parent");
186 if (!ASSERT_GE(cg_parent, 0, "join_cgroup /parent"))
187 goto out;
188
189 cg_child = test__join_cgroup("/parent/child");
190 if (!ASSERT_GE(cg_child, 0, "join_cgroup /parent/child"))
191 goto out;
192
193 sock_fd = socket(AF_INET, SOCK_STREAM, 0);
194 if (!ASSERT_GE(sock_fd, 0, "socket"))
195 goto out;
196
197 ASSERT_OK(run_getsockopt_test(cg_parent, cg_child, sock_fd, false), "getsockopt_test_1");
198 ASSERT_OK(run_getsockopt_test(cg_parent, cg_child, sock_fd, true), "getsockopt_test_2");
199 ASSERT_OK(run_link_replace_test(cg_child, sock_fd), "link_replace_test");
200
201 out:
202 close(sock_fd);
203 close(cg_child);
204 close(cg_parent);
205 }
206