1 // SPDX-License-Identifier: GPL-2.0
2 #include <unistd.h>
3 #include <test_progs.h>
4 #include <network_helpers.h>
5 #include "tailcall_poke.skel.h"
6
7
8 /* test_tailcall_1 checks basic functionality by patching multiple locations
9 * in a single program for a single tail call slot with nop->jmp, jmp->nop
10 * and jmp->jmp rewrites. Also checks for nop->nop.
11 */
12 static void test_tailcall_1(void)
13 {
14 int err, map_fd, prog_fd, main_fd, i, j;
15 struct bpf_map *prog_array;
16 struct bpf_program *prog;
17 struct bpf_object *obj;
18 char prog_name[32];
19 char buff[128] = {};
20 LIBBPF_OPTS(bpf_test_run_opts, topts,
21 .data_in = buff,
22 .data_size_in = sizeof(buff),
23 .repeat = 1,
24 );
25
26 err = bpf_prog_test_load("tailcall1.bpf.o", BPF_PROG_TYPE_SCHED_CLS, &obj,
27 &prog_fd);
28 if (CHECK_FAIL(err))
29 return;
30
31 prog = bpf_object__find_program_by_name(obj, "entry");
32 if (CHECK_FAIL(!prog))
33 goto out;
34
35 main_fd = bpf_program__fd(prog);
36 if (CHECK_FAIL(main_fd < 0))
37 goto out;
38
39 prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
40 if (CHECK_FAIL(!prog_array))
41 goto out;
42
43 map_fd = bpf_map__fd(prog_array);
44 if (CHECK_FAIL(map_fd < 0))
45 goto out;
46
47 for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
48 snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
49
50 prog = bpf_object__find_program_by_name(obj, prog_name);
51 if (CHECK_FAIL(!prog))
52 goto out;
53
54 prog_fd = bpf_program__fd(prog);
55 if (CHECK_FAIL(prog_fd < 0))
56 goto out;
57
58 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
59 if (CHECK_FAIL(err))
60 goto out;
61 }
62
63 for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
64 err = bpf_prog_test_run_opts(main_fd, &topts);
65 ASSERT_OK(err, "tailcall");
66 ASSERT_EQ(topts.retval, i, "tailcall retval");
67
68 err = bpf_map_delete_elem(map_fd, &i);
69 if (CHECK_FAIL(err))
70 goto out;
71 }
72
73 err = bpf_prog_test_run_opts(main_fd, &topts);
74 ASSERT_OK(err, "tailcall");
75 ASSERT_EQ(topts.retval, 3, "tailcall retval");
76
77 for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
78 snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
79
80 prog = bpf_object__find_program_by_name(obj, prog_name);
81 if (CHECK_FAIL(!prog))
82 goto out;
83
84 prog_fd = bpf_program__fd(prog);
85 if (CHECK_FAIL(prog_fd < 0))
86 goto out;
87
88 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
89 if (CHECK_FAIL(err))
90 goto out;
91 }
92
93 err = bpf_prog_test_run_opts(main_fd, &topts);
94 ASSERT_OK(err, "tailcall");
95 ASSERT_OK(topts.retval, "tailcall retval");
96
97 for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
98 j = bpf_map__max_entries(prog_array) - 1 - i;
99 snprintf(prog_name, sizeof(prog_name), "classifier_%d", j);
100
101 prog = bpf_object__find_program_by_name(obj, prog_name);
102 if (CHECK_FAIL(!prog))
103 goto out;
104
105 prog_fd = bpf_program__fd(prog);
106 if (CHECK_FAIL(prog_fd < 0))
107 goto out;
108
109 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
110 if (CHECK_FAIL(err))
111 goto out;
112 }
113
114 for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
115 j = bpf_map__max_entries(prog_array) - 1 - i;
116
117 err = bpf_prog_test_run_opts(main_fd, &topts);
118 ASSERT_OK(err, "tailcall");
119 ASSERT_EQ(topts.retval, j, "tailcall retval");
120
121 err = bpf_map_delete_elem(map_fd, &i);
122 if (CHECK_FAIL(err))
123 goto out;
124 }
125
126 err = bpf_prog_test_run_opts(main_fd, &topts);
127 ASSERT_OK(err, "tailcall");
128 ASSERT_EQ(topts.retval, 3, "tailcall retval");
129
130 for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
131 err = bpf_map_delete_elem(map_fd, &i);
132 if (CHECK_FAIL(err >= 0 || errno != ENOENT))
133 goto out;
134
135 err = bpf_prog_test_run_opts(main_fd, &topts);
136 ASSERT_OK(err, "tailcall");
137 ASSERT_EQ(topts.retval, 3, "tailcall retval");
138 }
139
140 out:
141 bpf_object__close(obj);
142 }
143
144 /* test_tailcall_2 checks that patching multiple programs for a single
145 * tail call slot works. It also jumps through several programs and tests
146 * the tail call limit counter.
147 */
148 static void test_tailcall_2(void)
149 {
150 int err, map_fd, prog_fd, main_fd, i;
151 struct bpf_map *prog_array;
152 struct bpf_program *prog;
153 struct bpf_object *obj;
154 char prog_name[32];
155 char buff[128] = {};
156 LIBBPF_OPTS(bpf_test_run_opts, topts,
157 .data_in = buff,
158 .data_size_in = sizeof(buff),
159 .repeat = 1,
160 );
161
162 err = bpf_prog_test_load("tailcall2.bpf.o", BPF_PROG_TYPE_SCHED_CLS, &obj,
163 &prog_fd);
164 if (CHECK_FAIL(err))
165 return;
166
167 prog = bpf_object__find_program_by_name(obj, "entry");
168 if (CHECK_FAIL(!prog))
169 goto out;
170
171 main_fd = bpf_program__fd(prog);
172 if (CHECK_FAIL(main_fd < 0))
173 goto out;
174
175 prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
176 if (CHECK_FAIL(!prog_array))
177 goto out;
178
179 map_fd = bpf_map__fd(prog_array);
180 if (CHECK_FAIL(map_fd < 0))
181 goto out;
182
183 for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
184 snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
185
186 prog = bpf_object__find_program_by_name(obj, prog_name);
187 if (CHECK_FAIL(!prog))
188 goto out;
189
190 prog_fd = bpf_program__fd(prog);
191 if (CHECK_FAIL(prog_fd < 0))
192 goto out;
193
194 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
195 if (CHECK_FAIL(err))
196 goto out;
197 }
198
199 err = bpf_prog_test_run_opts(main_fd, &topts);
200 ASSERT_OK(err, "tailcall");
201 ASSERT_EQ(topts.retval, 2, "tailcall retval");
202
203 i = 2;
204 err = bpf_map_delete_elem(map_fd, &i);
205 if (CHECK_FAIL(err))
206 goto out;
207
208 err = bpf_prog_test_run_opts(main_fd, &topts);
209 ASSERT_OK(err, "tailcall");
210 ASSERT_EQ(topts.retval, 1, "tailcall retval");
211
212 i = 0;
213 err = bpf_map_delete_elem(map_fd, &i);
214 if (CHECK_FAIL(err))
215 goto out;
216
217 err = bpf_prog_test_run_opts(main_fd, &topts);
218 ASSERT_OK(err, "tailcall");
219 ASSERT_EQ(topts.retval, 3, "tailcall retval");
220 out:
221 bpf_object__close(obj);
222 }
223
224 static void test_tailcall_count(const char *which, bool test_fentry,
225 bool test_fexit)
226 {
227 struct bpf_object *obj = NULL, *fentry_obj = NULL, *fexit_obj = NULL;
228 struct bpf_link *fentry_link = NULL, *fexit_link = NULL;
229 int err, map_fd, prog_fd, main_fd, data_fd, i, val;
230 struct bpf_map *prog_array, *data_map;
231 struct bpf_program *prog;
232 char buff[128] = {};
233 LIBBPF_OPTS(bpf_test_run_opts, topts,
234 .data_in = buff,
235 .data_size_in = sizeof(buff),
236 .repeat = 1,
237 );
238
239 err = bpf_prog_test_load(which, BPF_PROG_TYPE_SCHED_CLS, &obj,
240 &prog_fd);
241 if (CHECK_FAIL(err))
242 return;
243
244 prog = bpf_object__find_program_by_name(obj, "entry");
245 if (CHECK_FAIL(!prog))
246 goto out;
247
248 main_fd = bpf_program__fd(prog);
249 if (CHECK_FAIL(main_fd < 0))
250 goto out;
251
252 prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
253 if (CHECK_FAIL(!prog_array))
254 goto out;
255
256 map_fd = bpf_map__fd(prog_array);
257 if (CHECK_FAIL(map_fd < 0))
258 goto out;
259
260 prog = bpf_object__find_program_by_name(obj, "classifier_0");
261 if (CHECK_FAIL(!prog))
262 goto out;
263
264 prog_fd = bpf_program__fd(prog);
265 if (CHECK_FAIL(prog_fd < 0))
266 goto out;
267
268 i = 0;
269 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
270 if (CHECK_FAIL(err))
271 goto out;
272
273 if (test_fentry) {
274 fentry_obj = bpf_object__open_file("tailcall_bpf2bpf_fentry.bpf.o",
275 NULL);
276 if (!ASSERT_OK_PTR(fentry_obj, "open fentry_obj file"))
277 goto out;
278
279 prog = bpf_object__find_program_by_name(fentry_obj, "fentry");
280 if (!ASSERT_OK_PTR(prog, "find fentry prog"))
281 goto out;
282
283 err = bpf_program__set_attach_target(prog, prog_fd,
284 "subprog_tail");
285 if (!ASSERT_OK(err, "set_attach_target subprog_tail"))
286 goto out;
287
288 err = bpf_object__load(fentry_obj);
289 if (!ASSERT_OK(err, "load fentry_obj"))
290 goto out;
291
292 fentry_link = bpf_program__attach_trace(prog);
293 if (!ASSERT_OK_PTR(fentry_link, "attach_trace"))
294 goto out;
295 }
296
297 if (test_fexit) {
298 fexit_obj = bpf_object__open_file("tailcall_bpf2bpf_fexit.bpf.o",
299 NULL);
300 if (!ASSERT_OK_PTR(fexit_obj, "open fexit_obj file"))
301 goto out;
302
303 prog = bpf_object__find_program_by_name(fexit_obj, "fexit");
304 if (!ASSERT_OK_PTR(prog, "find fexit prog"))
305 goto out;
306
307 err = bpf_program__set_attach_target(prog, prog_fd,
308 "subprog_tail");
309 if (!ASSERT_OK(err, "set_attach_target subprog_tail"))
310 goto out;
311
312 err = bpf_object__load(fexit_obj);
313 if (!ASSERT_OK(err, "load fexit_obj"))
314 goto out;
315
316 fexit_link = bpf_program__attach_trace(prog);
317 if (!ASSERT_OK_PTR(fexit_link, "attach_trace"))
318 goto out;
319 }
320
321 err = bpf_prog_test_run_opts(main_fd, &topts);
322 ASSERT_OK(err, "tailcall");
323 ASSERT_EQ(topts.retval, 1, "tailcall retval");
324
325 data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");
326 if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))
327 goto out;
328
329 data_fd = bpf_map__fd(data_map);
330 if (CHECK_FAIL(data_fd < 0))
331 goto out;
332
333 i = 0;
334 err = bpf_map_lookup_elem(data_fd, &i, &val);
335 ASSERT_OK(err, "tailcall count");
336 ASSERT_EQ(val, 33, "tailcall count");
337
338 if (test_fentry) {
339 data_map = bpf_object__find_map_by_name(fentry_obj, ".bss");
340 if (!ASSERT_FALSE(!data_map || !bpf_map__is_internal(data_map),
341 "find tailcall_bpf2bpf_fentry.bss map"))
342 goto out;
343
344 data_fd = bpf_map__fd(data_map);
345 if (!ASSERT_FALSE(data_fd < 0,
346 "find tailcall_bpf2bpf_fentry.bss map fd"))
347 goto out;
348
349 i = 0;
350 err = bpf_map_lookup_elem(data_fd, &i, &val);
351 ASSERT_OK(err, "fentry count");
352 ASSERT_EQ(val, 33, "fentry count");
353 }
354
355 if (test_fexit) {
356 data_map = bpf_object__find_map_by_name(fexit_obj, ".bss");
357 if (!ASSERT_FALSE(!data_map || !bpf_map__is_internal(data_map),
358 "find tailcall_bpf2bpf_fexit.bss map"))
359 goto out;
360
361 data_fd = bpf_map__fd(data_map);
362 if (!ASSERT_FALSE(data_fd < 0,
363 "find tailcall_bpf2bpf_fexit.bss map fd"))
364 goto out;
365
366 i = 0;
367 err = bpf_map_lookup_elem(data_fd, &i, &val);
368 ASSERT_OK(err, "fexit count");
369 ASSERT_EQ(val, 33, "fexit count");
370 }
371
372 i = 0;
373 err = bpf_map_delete_elem(map_fd, &i);
374 if (CHECK_FAIL(err))
375 goto out;
376
377 err = bpf_prog_test_run_opts(main_fd, &topts);
378 ASSERT_OK(err, "tailcall");
379 ASSERT_OK(topts.retval, "tailcall retval");
380 out:
381 bpf_link__destroy(fentry_link);
382 bpf_link__destroy(fexit_link);
383 bpf_object__close(fentry_obj);
384 bpf_object__close(fexit_obj);
385 bpf_object__close(obj);
386 }
387
388 /* test_tailcall_3 checks that the count value of the tail call limit
389 * enforcement matches with expectations. JIT uses direct jump.
390 */
391 static void test_tailcall_3(void)
392 {
393 test_tailcall_count("tailcall3.bpf.o", false, false);
394 }
395
396 /* test_tailcall_6 checks that the count value of the tail call limit
397 * enforcement matches with expectations. JIT uses indirect jump.
398 */
399 static void test_tailcall_6(void)
400 {
401 test_tailcall_count("tailcall6.bpf.o", false, false);
402 }
403
404 /* test_tailcall_4 checks that the kernel properly selects indirect jump
405 * for the case where the key is not known. Latter is passed via global
406 * data to select different targets we can compare return value of.
407 */
408 static void test_tailcall_4(void)
409 {
410 int err, map_fd, prog_fd, main_fd, data_fd, i;
411 struct bpf_map *prog_array, *data_map;
412 struct bpf_program *prog;
413 struct bpf_object *obj;
414 static const int zero = 0;
415 char buff[128] = {};
416 char prog_name[32];
417 LIBBPF_OPTS(bpf_test_run_opts, topts,
418 .data_in = buff,
419 .data_size_in = sizeof(buff),
420 .repeat = 1,
421 );
422
423 err = bpf_prog_test_load("tailcall4.bpf.o", BPF_PROG_TYPE_SCHED_CLS, &obj,
424 &prog_fd);
425 if (CHECK_FAIL(err))
426 return;
427
428 prog = bpf_object__find_program_by_name(obj, "entry");
429 if (CHECK_FAIL(!prog))
430 goto out;
431
432 main_fd = bpf_program__fd(prog);
433 if (CHECK_FAIL(main_fd < 0))
434 goto out;
435
436 prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
437 if (CHECK_FAIL(!prog_array))
438 goto out;
439
440 map_fd = bpf_map__fd(prog_array);
441 if (CHECK_FAIL(map_fd < 0))
442 goto out;
443
444 data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");
445 if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))
446 goto out;
447
448 data_fd = bpf_map__fd(data_map);
449 if (CHECK_FAIL(data_fd < 0))
450 goto out;
451
452 for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
453 snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
454
455 prog = bpf_object__find_program_by_name(obj, prog_name);
456 if (CHECK_FAIL(!prog))
457 goto out;
458
459 prog_fd = bpf_program__fd(prog);
460 if (CHECK_FAIL(prog_fd < 0))
461 goto out;
462
463 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
464 if (CHECK_FAIL(err))
465 goto out;
466 }
467
468 for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
469 err = bpf_map_update_elem(data_fd, &zero, &i, BPF_ANY);
470 if (CHECK_FAIL(err))
471 goto out;
472
473 err = bpf_prog_test_run_opts(main_fd, &topts);
474 ASSERT_OK(err, "tailcall");
475 ASSERT_EQ(topts.retval, i, "tailcall retval");
476 }
477
478 for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
479 err = bpf_map_update_elem(data_fd, &zero, &i, BPF_ANY);
480 if (CHECK_FAIL(err))
481 goto out;
482
483 err = bpf_map_delete_elem(map_fd, &i);
484 if (CHECK_FAIL(err))
485 goto out;
486
487 err = bpf_prog_test_run_opts(main_fd, &topts);
488 ASSERT_OK(err, "tailcall");
489 ASSERT_EQ(topts.retval, 3, "tailcall retval");
490 }
491 out:
492 bpf_object__close(obj);
493 }
494
495 /* test_tailcall_5 probes similarly to test_tailcall_4 that the kernel generates
496 * an indirect jump when the keys are const but different from different branches.
497 */
498 static void test_tailcall_5(void)
499 {
500 int err, map_fd, prog_fd, main_fd, data_fd, i, key[] = { 1111, 1234, 5678 };
501 struct bpf_map *prog_array, *data_map;
502 struct bpf_program *prog;
503 struct bpf_object *obj;
504 static const int zero = 0;
505 char buff[128] = {};
506 char prog_name[32];
507 LIBBPF_OPTS(bpf_test_run_opts, topts,
508 .data_in = buff,
509 .data_size_in = sizeof(buff),
510 .repeat = 1,
511 );
512
513 err = bpf_prog_test_load("tailcall5.bpf.o", BPF_PROG_TYPE_SCHED_CLS, &obj,
514 &prog_fd);
515 if (CHECK_FAIL(err))
516 return;
517
518 prog = bpf_object__find_program_by_name(obj, "entry");
519 if (CHECK_FAIL(!prog))
520 goto out;
521
522 main_fd = bpf_program__fd(prog);
523 if (CHECK_FAIL(main_fd < 0))
524 goto out;
525
526 prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
527 if (CHECK_FAIL(!prog_array))
528 goto out;
529
530 map_fd = bpf_map__fd(prog_array);
531 if (CHECK_FAIL(map_fd < 0))
532 goto out;
533
534 data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");
535 if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))
536 goto out;
537
538 data_fd = bpf_map__fd(data_map);
539 if (CHECK_FAIL(data_fd < 0))
540 goto out;
541
542 for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
543 snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
544
545 prog = bpf_object__find_program_by_name(obj, prog_name);
546 if (CHECK_FAIL(!prog))
547 goto out;
548
549 prog_fd = bpf_program__fd(prog);
550 if (CHECK_FAIL(prog_fd < 0))
551 goto out;
552
553 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
554 if (CHECK_FAIL(err))
555 goto out;
556 }
557
558 for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
559 err = bpf_map_update_elem(data_fd, &zero, &key[i], BPF_ANY);
560 if (CHECK_FAIL(err))
561 goto out;
562
563 err = bpf_prog_test_run_opts(main_fd, &topts);
564 ASSERT_OK(err, "tailcall");
565 ASSERT_EQ(topts.retval, i, "tailcall retval");
566 }
567
568 for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
569 err = bpf_map_update_elem(data_fd, &zero, &key[i], BPF_ANY);
570 if (CHECK_FAIL(err))
571 goto out;
572
573 err = bpf_map_delete_elem(map_fd, &i);
574 if (CHECK_FAIL(err))
575 goto out;
576
577 err = bpf_prog_test_run_opts(main_fd, &topts);
578 ASSERT_OK(err, "tailcall");
579 ASSERT_EQ(topts.retval, 3, "tailcall retval");
580 }
581 out:
582 bpf_object__close(obj);
583 }
584
585 /* test_tailcall_bpf2bpf_1 purpose is to make sure that tailcalls are working
586 * correctly in correlation with BPF subprograms
587 */
588 static void test_tailcall_bpf2bpf_1(void)
589 {
590 int err, map_fd, prog_fd, main_fd, i;
591 struct bpf_map *prog_array;
592 struct bpf_program *prog;
593 struct bpf_object *obj;
594 char prog_name[32];
595 LIBBPF_OPTS(bpf_test_run_opts, topts,
596 .data_in = &pkt_v4,
597 .data_size_in = sizeof(pkt_v4),
598 .repeat = 1,
599 );
600
601 err = bpf_prog_test_load("tailcall_bpf2bpf1.bpf.o", BPF_PROG_TYPE_SCHED_CLS,
602 &obj, &prog_fd);
603 if (CHECK_FAIL(err))
604 return;
605
606 prog = bpf_object__find_program_by_name(obj, "entry");
607 if (CHECK_FAIL(!prog))
608 goto out;
609
610 main_fd = bpf_program__fd(prog);
611 if (CHECK_FAIL(main_fd < 0))
612 goto out;
613
614 prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
615 if (CHECK_FAIL(!prog_array))
616 goto out;
617
618 map_fd = bpf_map__fd(prog_array);
619 if (CHECK_FAIL(map_fd < 0))
620 goto out;
621
622 /* nop -> jmp */
623 for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
624 snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
625
626 prog = bpf_object__find_program_by_name(obj, prog_name);
627 if (CHECK_FAIL(!prog))
628 goto out;
629
630 prog_fd = bpf_program__fd(prog);
631 if (CHECK_FAIL(prog_fd < 0))
632 goto out;
633
634 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
635 if (CHECK_FAIL(err))
636 goto out;
637 }
638
639 err = bpf_prog_test_run_opts(main_fd, &topts);
640 ASSERT_OK(err, "tailcall");
641 ASSERT_EQ(topts.retval, 1, "tailcall retval");
642
643 /* jmp -> nop, call subprog that will do tailcall */
644 i = 1;
645 err = bpf_map_delete_elem(map_fd, &i);
646 if (CHECK_FAIL(err))
647 goto out;
648
649 err = bpf_prog_test_run_opts(main_fd, &topts);
650 ASSERT_OK(err, "tailcall");
651 ASSERT_OK(topts.retval, "tailcall retval");
652
653 /* make sure that subprog can access ctx and entry prog that
654 * called this subprog can properly return
655 */
656 i = 0;
657 err = bpf_map_delete_elem(map_fd, &i);
658 if (CHECK_FAIL(err))
659 goto out;
660
661 err = bpf_prog_test_run_opts(main_fd, &topts);
662 ASSERT_OK(err, "tailcall");
663 ASSERT_EQ(topts.retval, sizeof(pkt_v4) * 2, "tailcall retval");
664 out:
665 bpf_object__close(obj);
666 }
667
668 /* test_tailcall_bpf2bpf_2 checks that the count value of the tail call limit
669 * enforcement matches with expectations when tailcall is preceded with
670 * bpf2bpf call.
671 */
672 static void test_tailcall_bpf2bpf_2(void)
673 {
674 int err, map_fd, prog_fd, main_fd, data_fd, i, val;
675 struct bpf_map *prog_array, *data_map;
676 struct bpf_program *prog;
677 struct bpf_object *obj;
678 char buff[128] = {};
679 LIBBPF_OPTS(bpf_test_run_opts, topts,
680 .data_in = buff,
681 .data_size_in = sizeof(buff),
682 .repeat = 1,
683 );
684
685 err = bpf_prog_test_load("tailcall_bpf2bpf2.bpf.o", BPF_PROG_TYPE_SCHED_CLS,
686 &obj, &prog_fd);
687 if (CHECK_FAIL(err))
688 return;
689
690 prog = bpf_object__find_program_by_name(obj, "entry");
691 if (CHECK_FAIL(!prog))
692 goto out;
693
694 main_fd = bpf_program__fd(prog);
695 if (CHECK_FAIL(main_fd < 0))
696 goto out;
697
698 prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
699 if (CHECK_FAIL(!prog_array))
700 goto out;
701
702 map_fd = bpf_map__fd(prog_array);
703 if (CHECK_FAIL(map_fd < 0))
704 goto out;
705
706 prog = bpf_object__find_program_by_name(obj, "classifier_0");
707 if (CHECK_FAIL(!prog))
708 goto out;
709
710 prog_fd = bpf_program__fd(prog);
711 if (CHECK_FAIL(prog_fd < 0))
712 goto out;
713
714 i = 0;
715 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
716 if (CHECK_FAIL(err))
717 goto out;
718
719 err = bpf_prog_test_run_opts(main_fd, &topts);
720 ASSERT_OK(err, "tailcall");
721 ASSERT_EQ(topts.retval, 1, "tailcall retval");
722
723 data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");
724 if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))
725 goto out;
726
727 data_fd = bpf_map__fd(data_map);
728 if (CHECK_FAIL(data_fd < 0))
729 goto out;
730
731 i = 0;
732 err = bpf_map_lookup_elem(data_fd, &i, &val);
733 ASSERT_OK(err, "tailcall count");
734 ASSERT_EQ(val, 33, "tailcall count");
735
736 i = 0;
737 err = bpf_map_delete_elem(map_fd, &i);
738 if (CHECK_FAIL(err))
739 goto out;
740
741 err = bpf_prog_test_run_opts(main_fd, &topts);
742 ASSERT_OK(err, "tailcall");
743 ASSERT_OK(topts.retval, "tailcall retval");
744 out:
745 bpf_object__close(obj);
746 }
747
748 /* test_tailcall_bpf2bpf_3 checks that non-trivial amount of stack (up to
749 * 256 bytes) can be used within bpf subprograms that have the tailcalls
750 * in them
751 */
752 static void test_tailcall_bpf2bpf_3(void)
753 {
754 int err, map_fd, prog_fd, main_fd, i;
755 struct bpf_map *prog_array;
756 struct bpf_program *prog;
757 struct bpf_object *obj;
758 char prog_name[32];
759 LIBBPF_OPTS(bpf_test_run_opts, topts,
760 .data_in = &pkt_v4,
761 .data_size_in = sizeof(pkt_v4),
762 .repeat = 1,
763 );
764
765 err = bpf_prog_test_load("tailcall_bpf2bpf3.bpf.o", BPF_PROG_TYPE_SCHED_CLS,
766 &obj, &prog_fd);
767 if (CHECK_FAIL(err))
768 return;
769
770 prog = bpf_object__find_program_by_name(obj, "entry");
771 if (CHECK_FAIL(!prog))
772 goto out;
773
774 main_fd = bpf_program__fd(prog);
775 if (CHECK_FAIL(main_fd < 0))
776 goto out;
777
778 prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
779 if (CHECK_FAIL(!prog_array))
780 goto out;
781
782 map_fd = bpf_map__fd(prog_array);
783 if (CHECK_FAIL(map_fd < 0))
784 goto out;
785
786 for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
787 snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
788
789 prog = bpf_object__find_program_by_name(obj, prog_name);
790 if (CHECK_FAIL(!prog))
791 goto out;
792
793 prog_fd = bpf_program__fd(prog);
794 if (CHECK_FAIL(prog_fd < 0))
795 goto out;
796
797 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
798 if (CHECK_FAIL(err))
799 goto out;
800 }
801
802 err = bpf_prog_test_run_opts(main_fd, &topts);
803 ASSERT_OK(err, "tailcall");
804 ASSERT_EQ(topts.retval, sizeof(pkt_v4) * 3, "tailcall retval");
805
806 i = 1;
807 err = bpf_map_delete_elem(map_fd, &i);
808 if (CHECK_FAIL(err))
809 goto out;
810
811 err = bpf_prog_test_run_opts(main_fd, &topts);
812 ASSERT_OK(err, "tailcall");
813 ASSERT_EQ(topts.retval, sizeof(pkt_v4), "tailcall retval");
814
815 i = 0;
816 err = bpf_map_delete_elem(map_fd, &i);
817 if (CHECK_FAIL(err))
818 goto out;
819
820 err = bpf_prog_test_run_opts(main_fd, &topts);
821 ASSERT_OK(err, "tailcall");
822 ASSERT_EQ(topts.retval, sizeof(pkt_v4) * 2, "tailcall retval");
823 out:
824 bpf_object__close(obj);
825 }
826
827 #include "tailcall_bpf2bpf4.skel.h"
828
829 /* test_tailcall_bpf2bpf_4 checks that tailcall counter is correctly preserved
830 * across tailcalls combined with bpf2bpf calls. for making sure that tailcall
831 * counter behaves correctly, bpf program will go through following flow:
832 *
833 * entry -> entry_subprog -> tailcall0 -> bpf_func0 -> subprog0 ->
834 * -> tailcall1 -> bpf_func1 -> subprog1 -> tailcall2 -> bpf_func2 ->
835 * subprog2 [here bump global counter] --------^
836 *
837 * We go through first two tailcalls and start counting from the subprog2 where
838 * the loop begins. At the end of the test make sure that the global counter is
839 * equal to 31, because tailcall counter includes the first two tailcalls
840 * whereas global counter is incremented only on loop presented on flow above.
841 *
842 * The noise parameter is used to insert bpf_map_update calls into the logic
843 * to force verifier to patch instructions. This allows us to ensure jump
844 * logic remains correct with instruction movement.
845 */
846 static void test_tailcall_bpf2bpf_4(bool noise)
847 {
848 int err, map_fd, prog_fd, main_fd, data_fd, i;
849 struct tailcall_bpf2bpf4__bss val;
850 struct bpf_map *prog_array, *data_map;
851 struct bpf_program *prog;
852 struct bpf_object *obj;
853 char prog_name[32];
854 LIBBPF_OPTS(bpf_test_run_opts, topts,
855 .data_in = &pkt_v4,
856 .data_size_in = sizeof(pkt_v4),
857 .repeat = 1,
858 );
859
860 err = bpf_prog_test_load("tailcall_bpf2bpf4.bpf.o", BPF_PROG_TYPE_SCHED_CLS,
861 &obj, &prog_fd);
862 if (CHECK_FAIL(err))
863 return;
864
865 prog = bpf_object__find_program_by_name(obj, "entry");
866 if (CHECK_FAIL(!prog))
867 goto out;
868
869 main_fd = bpf_program__fd(prog);
870 if (CHECK_FAIL(main_fd < 0))
871 goto out;
872
873 prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
874 if (CHECK_FAIL(!prog_array))
875 goto out;
876
877 map_fd = bpf_map__fd(prog_array);
878 if (CHECK_FAIL(map_fd < 0))
879 goto out;
880
881 for (i = 0; i < bpf_map__max_entries(prog_array); i++) {
882 snprintf(prog_name, sizeof(prog_name), "classifier_%d", i);
883
884 prog = bpf_object__find_program_by_name(obj, prog_name);
885 if (CHECK_FAIL(!prog))
886 goto out;
887
888 prog_fd = bpf_program__fd(prog);
889 if (CHECK_FAIL(prog_fd < 0))
890 goto out;
891
892 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
893 if (CHECK_FAIL(err))
894 goto out;
895 }
896
897 data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");
898 if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))
899 goto out;
900
901 data_fd = bpf_map__fd(data_map);
902 if (CHECK_FAIL(data_fd < 0))
903 goto out;
904
905 i = 0;
906 val.noise = noise;
907 val.count = 0;
908 err = bpf_map_update_elem(data_fd, &i, &val, BPF_ANY);
909 if (CHECK_FAIL(err))
910 goto out;
911
912 err = bpf_prog_test_run_opts(main_fd, &topts);
913 ASSERT_OK(err, "tailcall");
914 ASSERT_EQ(topts.retval, sizeof(pkt_v4) * 3, "tailcall retval");
915
916 i = 0;
917 err = bpf_map_lookup_elem(data_fd, &i, &val);
918 ASSERT_OK(err, "tailcall count");
919 ASSERT_EQ(val.count, 31, "tailcall count");
920
921 out:
922 bpf_object__close(obj);
923 }
924
925 #include "tailcall_bpf2bpf6.skel.h"
926
927 /* Tail call counting works even when there is data on stack which is
928 * not aligned to 8 bytes.
929 */
930 static void test_tailcall_bpf2bpf_6(void)
931 {
932 struct tailcall_bpf2bpf6 *obj;
933 int err, map_fd, prog_fd, main_fd, data_fd, i, val;
934 LIBBPF_OPTS(bpf_test_run_opts, topts,
935 .data_in = &pkt_v4,
936 .data_size_in = sizeof(pkt_v4),
937 .repeat = 1,
938 );
939
940 obj = tailcall_bpf2bpf6__open_and_load();
941 if (!ASSERT_OK_PTR(obj, "open and load"))
942 return;
943
944 main_fd = bpf_program__fd(obj->progs.entry);
945 if (!ASSERT_GE(main_fd, 0, "entry prog fd"))
946 goto out;
947
948 map_fd = bpf_map__fd(obj->maps.jmp_table);
949 if (!ASSERT_GE(map_fd, 0, "jmp_table map fd"))
950 goto out;
951
952 prog_fd = bpf_program__fd(obj->progs.classifier_0);
953 if (!ASSERT_GE(prog_fd, 0, "classifier_0 prog fd"))
954 goto out;
955
956 i = 0;
957 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
958 if (!ASSERT_OK(err, "jmp_table map update"))
959 goto out;
960
961 err = bpf_prog_test_run_opts(main_fd, &topts);
962 ASSERT_OK(err, "entry prog test run");
963 ASSERT_EQ(topts.retval, 0, "tailcall retval");
964
965 data_fd = bpf_map__fd(obj->maps.bss);
966 if (!ASSERT_GE(data_fd, 0, "bss map fd"))
967 goto out;
968
969 i = 0;
970 err = bpf_map_lookup_elem(data_fd, &i, &val);
971 ASSERT_OK(err, "bss map lookup");
972 ASSERT_EQ(val, 1, "done flag is set");
973
974 out:
975 tailcall_bpf2bpf6__destroy(obj);
976 }
977
978 /* test_tailcall_bpf2bpf_fentry checks that the count value of the tail call
979 * limit enforcement matches with expectations when tailcall is preceded with
980 * bpf2bpf call, and the bpf2bpf call is traced by fentry.
981 */
982 static void test_tailcall_bpf2bpf_fentry(void)
983 {
984 test_tailcall_count("tailcall_bpf2bpf2.bpf.o", true, false);
985 }
986
987 /* test_tailcall_bpf2bpf_fexit checks that the count value of the tail call
988 * limit enforcement matches with expectations when tailcall is preceded with
989 * bpf2bpf call, and the bpf2bpf call is traced by fexit.
990 */
991 static void test_tailcall_bpf2bpf_fexit(void)
992 {
993 test_tailcall_count("tailcall_bpf2bpf2.bpf.o", false, true);
994 }
995
996 /* test_tailcall_bpf2bpf_fentry_fexit checks that the count value of the tail
997 * call limit enforcement matches with expectations when tailcall is preceded
998 * with bpf2bpf call, and the bpf2bpf call is traced by both fentry and fexit.
999 */
1000 static void test_tailcall_bpf2bpf_fentry_fexit(void)
1001 {
1002 test_tailcall_count("tailcall_bpf2bpf2.bpf.o", true, true);
1003 }
1004
1005 /* test_tailcall_bpf2bpf_fentry_entry checks that the count value of the tail
1006 * call limit enforcement matches with expectations when tailcall is preceded
1007 * with bpf2bpf call, and the bpf2bpf caller is traced by fentry.
1008 */
1009 static void test_tailcall_bpf2bpf_fentry_entry(void)
1010 {
1011 struct bpf_object *tgt_obj = NULL, *fentry_obj = NULL;
1012 int err, map_fd, prog_fd, data_fd, i, val;
1013 struct bpf_map *prog_array, *data_map;
1014 struct bpf_link *fentry_link = NULL;
1015 struct bpf_program *prog;
1016 char buff[128] = {};
1017
1018 LIBBPF_OPTS(bpf_test_run_opts, topts,
1019 .data_in = buff,
1020 .data_size_in = sizeof(buff),
1021 .repeat = 1,
1022 );
1023
1024 err = bpf_prog_test_load("tailcall_bpf2bpf2.bpf.o",
1025 BPF_PROG_TYPE_SCHED_CLS,
1026 &tgt_obj, &prog_fd);
1027 if (!ASSERT_OK(err, "load tgt_obj"))
1028 return;
1029
1030 prog_array = bpf_object__find_map_by_name(tgt_obj, "jmp_table");
1031 if (!ASSERT_OK_PTR(prog_array, "find jmp_table map"))
1032 goto out;
1033
1034 map_fd = bpf_map__fd(prog_array);
1035 if (!ASSERT_FALSE(map_fd < 0, "find jmp_table map fd"))
1036 goto out;
1037
1038 prog = bpf_object__find_program_by_name(tgt_obj, "classifier_0");
1039 if (!ASSERT_OK_PTR(prog, "find classifier_0 prog"))
1040 goto out;
1041
1042 prog_fd = bpf_program__fd(prog);
1043 if (!ASSERT_FALSE(prog_fd < 0, "find classifier_0 prog fd"))
1044 goto out;
1045
1046 i = 0;
1047 err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
1048 if (!ASSERT_OK(err, "update jmp_table"))
1049 goto out;
1050
1051 fentry_obj = bpf_object__open_file("tailcall_bpf2bpf_fentry.bpf.o",
1052 NULL);
1053 if (!ASSERT_OK_PTR(fentry_obj, "open fentry_obj file"))
1054 goto out;
1055
1056 prog = bpf_object__find_program_by_name(fentry_obj, "fentry");
1057 if (!ASSERT_OK_PTR(prog, "find fentry prog"))
1058 goto out;
1059
1060 err = bpf_program__set_attach_target(prog, prog_fd, "classifier_0");
1061 if (!ASSERT_OK(err, "set_attach_target classifier_0"))
1062 goto out;
1063
1064 err = bpf_object__load(fentry_obj);
1065 if (!ASSERT_OK(err, "load fentry_obj"))
1066 goto out;
1067
1068 fentry_link = bpf_program__attach_trace(prog);
1069 if (!ASSERT_OK_PTR(fentry_link, "attach_trace"))
1070 goto out;
1071
1072 err = bpf_prog_test_run_opts(prog_fd, &topts);
1073 ASSERT_OK(err, "tailcall");
1074 ASSERT_EQ(topts.retval, 1, "tailcall retval");
1075
1076 data_map = bpf_object__find_map_by_name(tgt_obj, "tailcall.bss");
1077 if (!ASSERT_FALSE(!data_map || !bpf_map__is_internal(data_map),
1078 "find tailcall.bss map"))
1079 goto out;
1080
1081 data_fd = bpf_map__fd(data_map);
1082 if (!ASSERT_FALSE(data_fd < 0, "find tailcall.bss map fd"))
1083 goto out;
1084
1085 i = 0;
1086 err = bpf_map_lookup_elem(data_fd, &i, &val);
1087 ASSERT_OK(err, "tailcall count");
1088 ASSERT_EQ(val, 34, "tailcall count");
1089
1090 data_map = bpf_object__find_map_by_name(fentry_obj, ".bss");
1091 if (!ASSERT_FALSE(!data_map || !bpf_map__is_internal(data_map),
1092 "find tailcall_bpf2bpf_fentry.bss map"))
1093 goto out;
1094
1095 data_fd = bpf_map__fd(data_map);
1096 if (!ASSERT_FALSE(data_fd < 0,
1097 "find tailcall_bpf2bpf_fentry.bss map fd"))
1098 goto out;
1099
1100 i = 0;
1101 err = bpf_map_lookup_elem(data_fd, &i, &val);
1102 ASSERT_OK(err, "fentry count");
1103 ASSERT_EQ(val, 1, "fentry count");
1104
1105 out:
1106 bpf_link__destroy(fentry_link);
1107 bpf_object__close(fentry_obj);
1108 bpf_object__close(tgt_obj);
1109 }
1110
1111 #define JMP_TABLE "/sys/fs/bpf/jmp_table"
1112
1113 static int poke_thread_exit;
1114
1115 static void *poke_update(void *arg)
1116 {
1117 __u32 zero = 0, prog1_fd, prog2_fd, map_fd;
1118 struct tailcall_poke *call = arg;
1119
1120 map_fd = bpf_map__fd(call->maps.jmp_table);
1121 prog1_fd = bpf_program__fd(call->progs.call1);
1122 prog2_fd = bpf_program__fd(call->progs.call2);
1123
1124 while (!poke_thread_exit) {
1125 bpf_map_update_elem(map_fd, &zero, &prog1_fd, BPF_ANY);
1126 bpf_map_update_elem(map_fd, &zero, &prog2_fd, BPF_ANY);
1127 }
1128
1129 return NULL;
1130 }
1131
1132 /*
1133 * We are trying to hit prog array update during another program load
1134 * that shares the same prog array map.
1135 *
1136 * For that we share the jmp_table map between two skeleton instances
1137 * by pinning the jmp_table to same path. Then first skeleton instance
1138 * periodically updates jmp_table in 'poke update' thread while we load
1139 * the second skeleton instance in the main thread.
1140 */
1141 static void test_tailcall_poke(void)
1142 {
1143 struct tailcall_poke *call, *test;
1144 int err, cnt = 10;
1145 pthread_t thread;
1146
1147 unlink(JMP_TABLE);
1148
1149 call = tailcall_poke__open_and_load();
1150 if (!ASSERT_OK_PTR(call, "tailcall_poke__open"))
1151 return;
1152
1153 err = bpf_map__pin(call->maps.jmp_table, JMP_TABLE);
1154 if (!ASSERT_OK(err, "bpf_map__pin"))
1155 goto out;
1156
1157 err = pthread_create(&thread, NULL, poke_update, call);
1158 if (!ASSERT_OK(err, "new toggler"))
1159 goto out;
1160
1161 while (cnt--) {
1162 test = tailcall_poke__open();
1163 if (!ASSERT_OK_PTR(test, "tailcall_poke__open"))
1164 break;
1165
1166 err = bpf_map__set_pin_path(test->maps.jmp_table, JMP_TABLE);
1167 if (!ASSERT_OK(err, "bpf_map__pin")) {
1168 tailcall_poke__destroy(test);
1169 break;
1170 }
1171
1172 bpf_program__set_autoload(test->progs.test, true);
1173 bpf_program__set_autoload(test->progs.call1, false);
1174 bpf_program__set_autoload(test->progs.call2, false);
1175
1176 err = tailcall_poke__load(test);
1177 tailcall_poke__destroy(test);
1178 if (!ASSERT_OK(err, "tailcall_poke__load"))
1179 break;
1180 }
1181
1182 poke_thread_exit = 1;
1183 ASSERT_OK(pthread_join(thread, NULL), "pthread_join");
1184
1185 out:
1186 bpf_map__unpin(call->maps.jmp_table, JMP_TABLE);
1187 tailcall_poke__destroy(call);
1188 }
1189
1190 void test_tailcalls(void)
1191 {
1192 if (test__start_subtest("tailcall_1"))
1193 test_tailcall_1();
1194 if (test__start_subtest("tailcall_2"))
1195 test_tailcall_2();
1196 if (test__start_subtest("tailcall_3"))
1197 test_tailcall_3();
1198 if (test__start_subtest("tailcall_4"))
1199 test_tailcall_4();
1200 if (test__start_subtest("tailcall_5"))
1201 test_tailcall_5();
1202 if (test__start_subtest("tailcall_6"))
1203 test_tailcall_6();
1204 if (test__start_subtest("tailcall_bpf2bpf_1"))
1205 test_tailcall_bpf2bpf_1();
1206 if (test__start_subtest("tailcall_bpf2bpf_2"))
1207 test_tailcall_bpf2bpf_2();
1208 if (test__start_subtest("tailcall_bpf2bpf_3"))
1209 test_tailcall_bpf2bpf_3();
1210 if (test__start_subtest("tailcall_bpf2bpf_4"))
1211 test_tailcall_bpf2bpf_4(false);
1212 if (test__start_subtest("tailcall_bpf2bpf_5"))
1213 test_tailcall_bpf2bpf_4(true);
1214 if (test__start_subtest("tailcall_bpf2bpf_6"))
1215 test_tailcall_bpf2bpf_6();
1216 if (test__start_subtest("tailcall_bpf2bpf_fentry"))
1217 test_tailcall_bpf2bpf_fentry();
1218 if (test__start_subtest("tailcall_bpf2bpf_fexit"))
1219 test_tailcall_bpf2bpf_fexit();
1220 if (test__start_subtest("tailcall_bpf2bpf_fentry_fexit"))
1221 test_tailcall_bpf2bpf_fentry_fexit();
1222 if (test__start_subtest("tailcall_bpf2bpf_fentry_entry"))
1223 test_tailcall_bpf2bpf_fentry_entry();
1224 if (test__start_subtest("tailcall_poke"))
1225 test_tailcall_poke();
1226 }
1227
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