1 // SPDX-License-Identifier: GPL-2.0
2 
3 #include <test_progs.h>
4 #include "cgroup_helpers.h"
5 #include "testing_helpers.h"
6 #include "test_cgroup_link.skel.h"
7 
8 static __u32 duration = 0;
9 #define PING_CMD	"ping -q -c1 -w1 127.0.0.1 > /dev/null"
10 
11 static struct test_cgroup_link *skel = NULL;
12 
13 int ping_and_check(int exp_calls, int exp_alt_calls)
14 {
15 	skel->bss->calls = 0;
16 	skel->bss->alt_calls = 0;
17 	CHECK_FAIL(system(PING_CMD));
18 	if (CHECK(skel->bss->calls != exp_calls, "call_cnt",
19 		  "exp %d, got %d\n", exp_calls, skel->bss->calls))
20 		return -EINVAL;
21 	if (CHECK(skel->bss->alt_calls != exp_alt_calls, "alt_call_cnt",
22 		  "exp %d, got %d\n", exp_alt_calls, skel->bss->alt_calls))
23 		return -EINVAL;
24 	return 0;
25 }
26 
27 void serial_test_cgroup_link(void)
28 {
29 	struct {
30 		const char *path;
31 		int fd;
32 	} cgs[] = {
33 		{ "/cg1" },
34 		{ "/cg1/cg2" },
35 		{ "/cg1/cg2/cg3" },
36 		{ "/cg1/cg2/cg3/cg4" },
37 	};
38 	int last_cg = ARRAY_SIZE(cgs) - 1, cg_nr = ARRAY_SIZE(cgs);
39 	DECLARE_LIBBPF_OPTS(bpf_link_update_opts, link_upd_opts);
40 	struct bpf_link *links[ARRAY_SIZE(cgs)] = {}, *tmp_link;
41 	__u32 prog_ids[ARRAY_SIZE(cgs)], prog_cnt = 0, attach_flags, prog_id;
42 	struct bpf_link_info info;
43 	int i = 0, err, prog_fd;
44 	bool detach_legacy = false;
45 
46 	skel = test_cgroup_link__open_and_load();
47 	if (CHECK(!skel, "skel_open_load", "failed to open/load skeleton\n"))
48 		return;
49 	prog_fd = bpf_program__fd(skel->progs.egress);
50 
51 	err = setup_cgroup_environment();
52 	if (CHECK(err, "cg_init", "failed: %d\n", err))
53 		goto cleanup;
54 
55 	for (i = 0; i < cg_nr; i++) {
56 		cgs[i].fd = create_and_get_cgroup(cgs[i].path);
57 		if (!ASSERT_GE(cgs[i].fd, 0, "cg_create"))
58 			goto cleanup;
59 	}
60 
61 	err = join_cgroup(cgs[last_cg].path);
62 	if (CHECK(err, "cg_join", "fail: %d\n", err))
63 		goto cleanup;
64 
65 	for (i = 0; i < cg_nr; i++) {
66 		links[i] = bpf_program__attach_cgroup(skel->progs.egress,
67 						      cgs[i].fd);
68 		if (!ASSERT_OK_PTR(links[i], "cg_attach"))
69 			goto cleanup;
70 	}
71 
72 	ping_and_check(cg_nr, 0);
73 
74 	/* query the number of effective progs and attach flags in root cg */
75 	err = bpf_prog_query(cgs[0].fd, BPF_CGROUP_INET_EGRESS,
76 			     BPF_F_QUERY_EFFECTIVE, &attach_flags, NULL,
77 			     &prog_cnt);
78 	CHECK_FAIL(err);
79 	CHECK_FAIL(attach_flags != BPF_F_ALLOW_MULTI);
80 	if (CHECK(prog_cnt != 1, "effect_cnt", "exp %d, got %d\n", 1, prog_cnt))
81 		goto cleanup;
82 
83 	/* query the number of effective progs in last cg */
84 	err = bpf_prog_query(cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS,
85 			     BPF_F_QUERY_EFFECTIVE, NULL, NULL,
86 			     &prog_cnt);
87 	CHECK_FAIL(err);
88 	CHECK_FAIL(attach_flags != BPF_F_ALLOW_MULTI);
89 	if (CHECK(prog_cnt != cg_nr, "effect_cnt", "exp %d, got %d\n",
90 		  cg_nr, prog_cnt))
91 		goto cleanup;
92 
93 	/* query the effective prog IDs in last cg */
94 	err = bpf_prog_query(cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS,
95 			     BPF_F_QUERY_EFFECTIVE, &attach_flags,
96 			     prog_ids, &prog_cnt);
97 	CHECK_FAIL(err);
98 	CHECK_FAIL(attach_flags != BPF_F_ALLOW_MULTI);
99 	if (CHECK(prog_cnt != cg_nr, "effect_cnt", "exp %d, got %d\n",
100 		  cg_nr, prog_cnt))
101 		goto cleanup;
102 	for (i = 1; i < prog_cnt; i++) {
103 		CHECK(prog_ids[i - 1] != prog_ids[i], "prog_id_check",
104 		      "idx %d, prev id %d, cur id %d\n",
105 		      i, prog_ids[i - 1], prog_ids[i]);
106 	}
107 
108 	/* detach bottom program and ping again */
109 	bpf_link__destroy(links[last_cg]);
110 	links[last_cg] = NULL;
111 
112 	ping_and_check(cg_nr - 1, 0);
113 
114 	/* mix in with non link-based multi-attachments */
115 	err = bpf_prog_attach(prog_fd, cgs[last_cg].fd,
116 			      BPF_CGROUP_INET_EGRESS, BPF_F_ALLOW_MULTI);
117 	if (CHECK(err, "cg_attach_legacy", "errno=%d\n", errno))
118 		goto cleanup;
119 	detach_legacy = true;
120 
121 	links[last_cg] = bpf_program__attach_cgroup(skel->progs.egress,
122 						    cgs[last_cg].fd);
123 	if (!ASSERT_OK_PTR(links[last_cg], "cg_attach"))
124 		goto cleanup;
125 
126 	ping_and_check(cg_nr + 1, 0);
127 
128 	/* detach link */
129 	bpf_link__destroy(links[last_cg]);
130 	links[last_cg] = NULL;
131 
132 	/* detach legacy */
133 	err = bpf_prog_detach2(prog_fd, cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS);
134 	if (CHECK(err, "cg_detach_legacy", "errno=%d\n", errno))
135 		goto cleanup;
136 	detach_legacy = false;
137 
138 	/* attach legacy exclusive prog attachment */
139 	err = bpf_prog_attach(prog_fd, cgs[last_cg].fd,
140 			      BPF_CGROUP_INET_EGRESS, 0);
141 	if (CHECK(err, "cg_attach_exclusive", "errno=%d\n", errno))
142 		goto cleanup;
143 	detach_legacy = true;
144 
145 	/* attempt to mix in with multi-attach bpf_link */
146 	tmp_link = bpf_program__attach_cgroup(skel->progs.egress,
147 					      cgs[last_cg].fd);
148 	if (!ASSERT_ERR_PTR(tmp_link, "cg_attach_fail")) {
149 		bpf_link__destroy(tmp_link);
150 		goto cleanup;
151 	}
152 
153 	ping_and_check(cg_nr, 0);
154 
155 	/* detach */
156 	err = bpf_prog_detach2(prog_fd, cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS);
157 	if (CHECK(err, "cg_detach_legacy", "errno=%d\n", errno))
158 		goto cleanup;
159 	detach_legacy = false;
160 
161 	ping_and_check(cg_nr - 1, 0);
162 
163 	/* attach back link-based one */
164 	links[last_cg] = bpf_program__attach_cgroup(skel->progs.egress,
165 						    cgs[last_cg].fd);
166 	if (!ASSERT_OK_PTR(links[last_cg], "cg_attach"))
167 		goto cleanup;
168 
169 	ping_and_check(cg_nr, 0);
170 
171 	/* check legacy exclusive prog can't be attached */
172 	err = bpf_prog_attach(prog_fd, cgs[last_cg].fd,
173 			      BPF_CGROUP_INET_EGRESS, 0);
174 	if (CHECK(!err, "cg_attach_exclusive", "unexpected success")) {
175 		bpf_prog_detach2(prog_fd, cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS);
176 		goto cleanup;
177 	}
178 
179 	/* replace BPF programs inside their links for all but first link */
180 	for (i = 1; i < cg_nr; i++) {
181 		err = bpf_link__update_program(links[i], skel->progs.egress_alt);
182 		if (CHECK(err, "prog_upd", "link #%d\n", i))
183 			goto cleanup;
184 	}
185 
186 	ping_and_check(1, cg_nr - 1);
187 
188 	/* Attempt program update with wrong expected BPF program */
189 	link_upd_opts.old_prog_fd = bpf_program__fd(skel->progs.egress_alt);
190 	link_upd_opts.flags = BPF_F_REPLACE;
191 	err = bpf_link_update(bpf_link__fd(links[0]),
192 			      bpf_program__fd(skel->progs.egress_alt),
193 			      &link_upd_opts);
194 	if (CHECK(err == 0 || errno != EPERM, "prog_cmpxchg1",
195 		  "unexpectedly succeeded, err %d, errno %d\n", err, -errno))
196 		goto cleanup;
197 
198 	/* Compare-exchange single link program from egress to egress_alt */
199 	link_upd_opts.old_prog_fd = bpf_program__fd(skel->progs.egress);
200 	link_upd_opts.flags = BPF_F_REPLACE;
201 	err = bpf_link_update(bpf_link__fd(links[0]),
202 			      bpf_program__fd(skel->progs.egress_alt),
203 			      &link_upd_opts);
204 	if (CHECK(err, "prog_cmpxchg2", "errno %d\n", -errno))
205 		goto cleanup;
206 
207 	/* ping */
208 	ping_and_check(0, cg_nr);
209 
210 	/* close cgroup FDs before detaching links */
211 	for (i = 0; i < cg_nr; i++) {
212 		if (cgs[i].fd > 0) {
213 			close(cgs[i].fd);
214 			cgs[i].fd = -1;
215 		}
216 	}
217 
218 	/* BPF programs should still get called */
219 	ping_and_check(0, cg_nr);
220 
221 	prog_id = link_info_prog_id(links[0], &info);
222 	CHECK(prog_id == 0, "link_info", "failed\n");
223 	CHECK(info.cgroup.cgroup_id == 0, "cgroup_id", "unexpected %llu\n", info.cgroup.cgroup_id);
224 
225 	err = bpf_link__detach(links[0]);
226 	if (CHECK(err, "link_detach", "failed %d\n", err))
227 		goto cleanup;
228 
229 	/* cgroup_id should be zero in link_info */
230 	prog_id = link_info_prog_id(links[0], &info);
231 	CHECK(prog_id == 0, "link_info", "failed\n");
232 	CHECK(info.cgroup.cgroup_id != 0, "cgroup_id", "unexpected %llu\n", info.cgroup.cgroup_id);
233 
234 	/* First BPF program shouldn't be called anymore */
235 	ping_and_check(0, cg_nr - 1);
236 
237 	/* leave cgroup and remove them, don't detach programs */
238 	cleanup_cgroup_environment();
239 
240 	/* BPF programs should have been auto-detached */
241 	ping_and_check(0, 0);
242 
243 cleanup:
244 	if (detach_legacy)
245 		bpf_prog_detach2(prog_fd, cgs[last_cg].fd,
246 				 BPF_CGROUP_INET_EGRESS);
247 
248 	for (i = 0; i < cg_nr; i++) {
249 		bpf_link__destroy(links[i]);
250 	}
251 	test_cgroup_link__destroy(skel);
252 
253 	for (i = 0; i < cg_nr; i++) {
254 		if (cgs[i].fd > 0)
255 			close(cgs[i].fd);
256 	}
257 	cleanup_cgroup_environment();
258 }
259