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1// SPDX-License-Identifier: GPL-2.0
2
3#include <limits.h>
4#include <stdio.h>
5#include <string.h>
6#include <ctype.h>
7#include <regex.h>
8#include <test_progs.h>
9
10#include "bpf/btf.h"
11#include "bpf_util.h"
12#include "linux/filter.h"
13#include "linux/kernel.h"
14#include "disasm_helpers.h"
15
16#define MAX_PROG_TEXT_SZ (32 * 1024)
17
18/* The code in this file serves the sole purpose of executing test cases
19 * specified in the test_cases array. Each test case specifies a program
20 * type, context field offset, and disassembly patterns that correspond
21 * to read and write instructions generated by
22 * verifier.c:convert_ctx_access() for accessing that field.
23 *
24 * For each test case, up to three programs are created:
25 * - One that uses BPF_LDX_MEM to read the context field.
26 * - One that uses BPF_STX_MEM to write to the context field.
27 * - One that uses BPF_ST_MEM to write to the context field.
28 *
29 * The disassembly of each program is then compared with the pattern
30 * specified in the test case.
31 */
32struct test_case {
33 char *name;
34 enum bpf_prog_type prog_type;
35 enum bpf_attach_type expected_attach_type;
36 int field_offset;
37 int field_sz;
38 /* Program generated for BPF_ST_MEM uses value 42 by default,
39 * this field allows to specify custom value.
40 */
41 struct {
42 bool use;
43 int value;
44 } st_value;
45 /* Pattern for BPF_LDX_MEM(field_sz, dst, ctx, field_offset) */
46 char *read;
47 /* Pattern for BPF_STX_MEM(field_sz, ctx, src, field_offset) and
48 * BPF_ST_MEM (field_sz, ctx, src, field_offset)
49 */
50 char *write;
51 /* Pattern for BPF_ST_MEM(field_sz, ctx, src, field_offset),
52 * takes priority over `write`.
53 */
54 char *write_st;
55 /* Pattern for BPF_STX_MEM (field_sz, ctx, src, field_offset),
56 * takes priority over `write`.
57 */
58 char *write_stx;
59};
60
61#define N(_prog_type, type, field, name_extra...) \
62 .name = #_prog_type "." #field name_extra, \
63 .prog_type = BPF_PROG_TYPE_##_prog_type, \
64 .field_offset = offsetof(type, field), \
65 .field_sz = sizeof(typeof(((type *)NULL)->field))
66
67static struct test_case test_cases[] = {
68/* Sign extension on s390 changes the pattern */
69#if defined(__x86_64__) || defined(__aarch64__)
70 {
71 N(SCHED_CLS, struct __sk_buff, tstamp),
72 .read = "r11 = *(u8 *)($ctx + sk_buff::__mono_tc_offset);"
73 "if w11 & 0x4 goto pc+1;"
74 "goto pc+4;"
75 "if w11 & 0x3 goto pc+1;"
76 "goto pc+2;"
77 "$dst = 0;"
78 "goto pc+1;"
79 "$dst = *(u64 *)($ctx + sk_buff::tstamp);",
80 .write = "r11 = *(u8 *)($ctx + sk_buff::__mono_tc_offset);"
81 "if w11 & 0x4 goto pc+1;"
82 "goto pc+2;"
83 "w11 &= -4;"
84 "*(u8 *)($ctx + sk_buff::__mono_tc_offset) = r11;"
85 "*(u64 *)($ctx + sk_buff::tstamp) = $src;",
86 },
87#endif
88 {
89 N(SCHED_CLS, struct __sk_buff, priority),
90 .read = "$dst = *(u32 *)($ctx + sk_buff::priority);",
91 .write = "*(u32 *)($ctx + sk_buff::priority) = $src;",
92 },
93 {
94 N(SCHED_CLS, struct __sk_buff, mark),
95 .read = "$dst = *(u32 *)($ctx + sk_buff::mark);",
96 .write = "*(u32 *)($ctx + sk_buff::mark) = $src;",
97 },
98 {
99 N(SCHED_CLS, struct __sk_buff, cb[0]),
100 .read = "$dst = *(u32 *)($ctx + $(sk_buff::cb + qdisc_skb_cb::data));",
101 .write = "*(u32 *)($ctx + $(sk_buff::cb + qdisc_skb_cb::data)) = $src;",
102 },
103 {
104 N(SCHED_CLS, struct __sk_buff, tc_classid),
105 .read = "$dst = *(u16 *)($ctx + $(sk_buff::cb + qdisc_skb_cb::tc_classid));",
106 .write = "*(u16 *)($ctx + $(sk_buff::cb + qdisc_skb_cb::tc_classid)) = $src;",
107 },
108 {
109 N(SCHED_CLS, struct __sk_buff, tc_index),
110 .read = "$dst = *(u16 *)($ctx + sk_buff::tc_index);",
111 .write = "*(u16 *)($ctx + sk_buff::tc_index) = $src;",
112 },
113 {
114 N(SCHED_CLS, struct __sk_buff, queue_mapping),
115 .read = "$dst = *(u16 *)($ctx + sk_buff::queue_mapping);",
116 .write_stx = "if $src >= 0xffff goto pc+1;"
117 "*(u16 *)($ctx + sk_buff::queue_mapping) = $src;",
118 .write_st = "*(u16 *)($ctx + sk_buff::queue_mapping) = $src;",
119 },
120 {
121 /* This is a corner case in filter.c:bpf_convert_ctx_access() */
122 N(SCHED_CLS, struct __sk_buff, queue_mapping, ".ushrt_max"),
123 .st_value = { true, USHRT_MAX },
124 .write_st = "goto pc+0;",
125 },
126 {
127 N(CGROUP_SOCK, struct bpf_sock, bound_dev_if),
128 .read = "$dst = *(u32 *)($ctx + sock_common::skc_bound_dev_if);",
129 .write = "*(u32 *)($ctx + sock_common::skc_bound_dev_if) = $src;",
130 },
131 {
132 N(CGROUP_SOCK, struct bpf_sock, mark),
133 .read = "$dst = *(u32 *)($ctx + sock::sk_mark);",
134 .write = "*(u32 *)($ctx + sock::sk_mark) = $src;",
135 },
136 {
137 N(CGROUP_SOCK, struct bpf_sock, priority),
138 .read = "$dst = *(u32 *)($ctx + sock::sk_priority);",
139 .write = "*(u32 *)($ctx + sock::sk_priority) = $src;",
140 },
141 {
142 N(SOCK_OPS, struct bpf_sock_ops, replylong[0]),
143 .read = "$dst = *(u32 *)($ctx + bpf_sock_ops_kern::replylong);",
144 .write = "*(u32 *)($ctx + bpf_sock_ops_kern::replylong) = $src;",
145 },
146 {
147 N(CGROUP_SYSCTL, struct bpf_sysctl, file_pos),
148#if __BYTE_ORDER == __LITTLE_ENDIAN
149 .read = "$dst = *(u64 *)($ctx + bpf_sysctl_kern::ppos);"
150 "$dst = *(u32 *)($dst +0);",
151 .write = "*(u64 *)($ctx + bpf_sysctl_kern::tmp_reg) = r9;"
152 "r9 = *(u64 *)($ctx + bpf_sysctl_kern::ppos);"
153 "*(u32 *)(r9 +0) = $src;"
154 "r9 = *(u64 *)($ctx + bpf_sysctl_kern::tmp_reg);",
155#else
156 .read = "$dst = *(u64 *)($ctx + bpf_sysctl_kern::ppos);"
157 "$dst = *(u32 *)($dst +4);",
158 .write = "*(u64 *)($ctx + bpf_sysctl_kern::tmp_reg) = r9;"
159 "r9 = *(u64 *)($ctx + bpf_sysctl_kern::ppos);"
160 "*(u32 *)(r9 +4) = $src;"
161 "r9 = *(u64 *)($ctx + bpf_sysctl_kern::tmp_reg);",
162#endif
163 },
164 {
165 N(CGROUP_SOCKOPT, struct bpf_sockopt, sk),
166 .read = "$dst = *(u64 *)($ctx + bpf_sockopt_kern::sk);",
167 .expected_attach_type = BPF_CGROUP_GETSOCKOPT,
168 },
169 {
170 N(CGROUP_SOCKOPT, struct bpf_sockopt, level),
171 .read = "$dst = *(u32 *)($ctx + bpf_sockopt_kern::level);",
172 .write = "*(u32 *)($ctx + bpf_sockopt_kern::level) = $src;",
173 .expected_attach_type = BPF_CGROUP_SETSOCKOPT,
174 },
175 {
176 N(CGROUP_SOCKOPT, struct bpf_sockopt, optname),
177 .read = "$dst = *(u32 *)($ctx + bpf_sockopt_kern::optname);",
178 .write = "*(u32 *)($ctx + bpf_sockopt_kern::optname) = $src;",
179 .expected_attach_type = BPF_CGROUP_SETSOCKOPT,
180 },
181 {
182 N(CGROUP_SOCKOPT, struct bpf_sockopt, optlen),
183 .read = "$dst = *(u32 *)($ctx + bpf_sockopt_kern::optlen);",
184 .write = "*(u32 *)($ctx + bpf_sockopt_kern::optlen) = $src;",
185 .expected_attach_type = BPF_CGROUP_SETSOCKOPT,
186 },
187 {
188 N(CGROUP_SOCKOPT, struct bpf_sockopt, retval),
189 .read = "$dst = *(u64 *)($ctx + bpf_sockopt_kern::current_task);"
190 "$dst = *(u64 *)($dst + task_struct::bpf_ctx);"
191 "$dst = *(u32 *)($dst + bpf_cg_run_ctx::retval);",
192 .write = "*(u64 *)($ctx + bpf_sockopt_kern::tmp_reg) = r9;"
193 "r9 = *(u64 *)($ctx + bpf_sockopt_kern::current_task);"
194 "r9 = *(u64 *)(r9 + task_struct::bpf_ctx);"
195 "*(u32 *)(r9 + bpf_cg_run_ctx::retval) = $src;"
196 "r9 = *(u64 *)($ctx + bpf_sockopt_kern::tmp_reg);",
197 .expected_attach_type = BPF_CGROUP_GETSOCKOPT,
198 },
199 {
200 N(CGROUP_SOCKOPT, struct bpf_sockopt, optval),
201 .read = "$dst = *(u64 *)($ctx + bpf_sockopt_kern::optval);",
202 .expected_attach_type = BPF_CGROUP_GETSOCKOPT,
203 },
204 {
205 N(CGROUP_SOCKOPT, struct bpf_sockopt, optval_end),
206 .read = "$dst = *(u64 *)($ctx + bpf_sockopt_kern::optval_end);",
207 .expected_attach_type = BPF_CGROUP_GETSOCKOPT,
208 },
209};
210
211#undef N
212
213static regex_t *ident_regex;
214static regex_t *field_regex;
215
216static char *skip_space(char *str)
217{
218 while (*str && isspace(*str))
219 ++str;
220 return str;
221}
222
223static char *skip_space_and_semi(char *str)
224{
225 while (*str && (isspace(*str) || *str == ';'))
226 ++str;
227 return str;
228}
229
230static char *match_str(char *str, char *prefix)
231{
232 while (*str && *prefix && *str == *prefix) {
233 ++str;
234 ++prefix;
235 }
236 if (*prefix)
237 return NULL;
238 return str;
239}
240
241static char *match_number(char *str, int num)
242{
243 char *next;
244 int snum = strtol(str, &next, 10);
245
246 if (next - str == 0 || num != snum)
247 return NULL;
248
249 return next;
250}
251
252static int find_field_offset_aux(struct btf *btf, int btf_id, char *field_name, int off)
253{
254 const struct btf_type *type = btf__type_by_id(btf, btf_id);
255 const struct btf_member *m;
256 __u16 mnum;
257 int i;
258
259 if (!type) {
260 PRINT_FAIL("Can't find btf_type for id %d\n", btf_id);
261 return -1;
262 }
263
264 if (!btf_is_struct(type) && !btf_is_union(type)) {
265 PRINT_FAIL("BTF id %d is not struct or union\n", btf_id);
266 return -1;
267 }
268
269 m = btf_members(type);
270 mnum = btf_vlen(type);
271
272 for (i = 0; i < mnum; ++i, ++m) {
273 const char *mname = btf__name_by_offset(btf, m->name_off);
274
275 if (strcmp(mname, "") == 0) {
276 int msize = find_field_offset_aux(btf, m->type, field_name,
277 off + m->offset);
278 if (msize >= 0)
279 return msize;
280 }
281
282 if (strcmp(mname, field_name))
283 continue;
284
285 return (off + m->offset) / 8;
286 }
287
288 return -1;
289}
290
291static int find_field_offset(struct btf *btf, char *pattern, regmatch_t *matches)
292{
293 int type_sz = matches[1].rm_eo - matches[1].rm_so;
294 int field_sz = matches[2].rm_eo - matches[2].rm_so;
295 char *type = pattern + matches[1].rm_so;
296 char *field = pattern + matches[2].rm_so;
297 char field_str[128] = {};
298 char type_str[128] = {};
299 int btf_id, field_offset;
300
301 if (type_sz >= sizeof(type_str)) {
302 PRINT_FAIL("Malformed pattern: type ident is too long: %d\n", type_sz);
303 return -1;
304 }
305
306 if (field_sz >= sizeof(field_str)) {
307 PRINT_FAIL("Malformed pattern: field ident is too long: %d\n", field_sz);
308 return -1;
309 }
310
311 strncpy(type_str, type, type_sz);
312 strncpy(field_str, field, field_sz);
313 btf_id = btf__find_by_name(btf, type_str);
314 if (btf_id < 0) {
315 PRINT_FAIL("No BTF info for type %s\n", type_str);
316 return -1;
317 }
318
319 field_offset = find_field_offset_aux(btf, btf_id, field_str, 0);
320 if (field_offset < 0) {
321 PRINT_FAIL("No BTF info for field %s::%s\n", type_str, field_str);
322 return -1;
323 }
324
325 return field_offset;
326}
327
328static regex_t *compile_regex(char *pat)
329{
330 regex_t *re;
331 int err;
332
333 re = malloc(sizeof(regex_t));
334 if (!re) {
335 PRINT_FAIL("Can't alloc regex\n");
336 return NULL;
337 }
338
339 err = regcomp(re, pat, REG_EXTENDED);
340 if (err) {
341 char errbuf[512];
342
343 regerror(err, re, errbuf, sizeof(errbuf));
344 PRINT_FAIL("Can't compile regex: %s\n", errbuf);
345 free(re);
346 return NULL;
347 }
348
349 return re;
350}
351
352static void free_regex(regex_t *re)
353{
354 if (!re)
355 return;
356
357 regfree(re);
358 free(re);
359}
360
361static u32 max_line_len(char *str)
362{
363 u32 max_line = 0;
364 char *next = str;
365
366 while (next) {
367 next = strchr(str, '\n');
368 if (next) {
369 max_line = max_t(u32, max_line, (next - str));
370 str = next + 1;
371 } else {
372 max_line = max_t(u32, max_line, strlen(str));
373 }
374 }
375
376 return min(max_line, 60u);
377}
378
379/* Print strings `pattern_origin` and `text_origin` side by side,
380 * assume `pattern_pos` and `text_pos` designate location within
381 * corresponding origin string where match diverges.
382 * The output should look like:
383 *
384 * Can't match disassembly(left) with pattern(right):
385 * r2 = *(u64 *)(r1 +0) ; $dst = *(u64 *)($ctx + bpf_sockopt_kern::sk1)
386 * ^ ^
387 * r0 = 0 ;
388 * exit ;
389 */
390static void print_match_error(FILE *out,
391 char *pattern_origin, char *text_origin,
392 char *pattern_pos, char *text_pos)
393{
394 char *pattern = pattern_origin;
395 char *text = text_origin;
396 int middle = max_line_len(text) + 2;
397
398 fprintf(out, "Can't match disassembly(left) with pattern(right):\n");
399 while (*pattern || *text) {
400 int column = 0;
401 int mark1 = -1;
402 int mark2 = -1;
403
404 /* Print one line from text */
405 while (*text && *text != '\n') {
406 if (text == text_pos)
407 mark1 = column;
408 fputc(*text, out);
409 ++text;
410 ++column;
411 }
412 if (text == text_pos)
413 mark1 = column;
414
415 /* Pad to the middle */
416 while (column < middle) {
417 fputc(' ', out);
418 ++column;
419 }
420 fputs("; ", out);
421 column += 3;
422
423 /* Print one line from pattern, pattern lines are terminated by ';' */
424 while (*pattern && *pattern != ';') {
425 if (pattern == pattern_pos)
426 mark2 = column;
427 fputc(*pattern, out);
428 ++pattern;
429 ++column;
430 }
431 if (pattern == pattern_pos)
432 mark2 = column;
433
434 fputc('\n', out);
435 if (*pattern)
436 ++pattern;
437 if (*text)
438 ++text;
439
440 /* If pattern and text diverge at this line, print an
441 * additional line with '^' marks, highlighting
442 * positions where match fails.
443 */
444 if (mark1 > 0 || mark2 > 0) {
445 for (column = 0; column <= max(mark1, mark2); ++column) {
446 if (column == mark1 || column == mark2)
447 fputc('^', out);
448 else
449 fputc(' ', out);
450 }
451 fputc('\n', out);
452 }
453 }
454}
455
456/* Test if `text` matches `pattern`. Pattern consists of the following elements:
457 *
458 * - Field offset references:
459 *
460 * <type>::<field>
461 *
462 * When such reference is encountered BTF is used to compute numerical
463 * value for the offset of <field> in <type>. The `text` is expected to
464 * contain matching numerical value.
465 *
466 * - Field groups:
467 *
468 * $(<type>::<field> [+ <type>::<field>]*)
469 *
470 * Allows to specify an offset that is a sum of multiple field offsets.
471 * The `text` is expected to contain matching numerical value.
472 *
473 * - Variable references, e.g. `$src`, `$dst`, `$ctx`.
474 * These are substitutions specified in `reg_map` array.
475 * If a substring of pattern is equal to `reg_map[i][0]` the `text` is
476 * expected to contain `reg_map[i][1]` in the matching position.
477 *
478 * - Whitespace is ignored, ';' counts as whitespace for `pattern`.
479 *
480 * - Any other characters, `pattern` and `text` should match one-to-one.
481 *
482 * Example of a pattern:
483 *
484 * __________ fields group ________________
485 * ' '
486 * *(u16 *)($ctx + $(sk_buff::cb + qdisc_skb_cb::tc_classid)) = $src;
487 * ^^^^ '______________________'
488 * variable reference field offset reference
489 */
490static bool match_pattern(struct btf *btf, char *pattern, char *text, char *reg_map[][2])
491{
492 char *pattern_origin = pattern;
493 char *text_origin = text;
494 regmatch_t matches[3];
495
496_continue:
497 while (*pattern) {
498 if (!*text)
499 goto err;
500
501 /* Skip whitespace */
502 if (isspace(*pattern) || *pattern == ';') {
503 if (!isspace(*text) && text != text_origin && isalnum(text[-1]))
504 goto err;
505 pattern = skip_space_and_semi(pattern);
506 text = skip_space(text);
507 continue;
508 }
509
510 /* Check for variable references */
511 for (int i = 0; reg_map[i][0]; ++i) {
512 char *pattern_next, *text_next;
513
514 pattern_next = match_str(pattern, reg_map[i][0]);
515 if (!pattern_next)
516 continue;
517
518 text_next = match_str(text, reg_map[i][1]);
519 if (!text_next)
520 goto err;
521
522 pattern = pattern_next;
523 text = text_next;
524 goto _continue;
525 }
526
527 /* Match field group:
528 * $(sk_buff::cb + qdisc_skb_cb::tc_classid)
529 */
530 if (strncmp(pattern, "$(", 2) == 0) {
531 char *group_start = pattern, *text_next;
532 int acc_offset = 0;
533
534 pattern += 2;
535
536 for (;;) {
537 int field_offset;
538
539 pattern = skip_space(pattern);
540 if (!*pattern) {
541 PRINT_FAIL("Unexpected end of pattern\n");
542 goto err;
543 }
544
545 if (*pattern == ')') {
546 ++pattern;
547 break;
548 }
549
550 if (*pattern == '+') {
551 ++pattern;
552 continue;
553 }
554
555 printf("pattern: %s\n", pattern);
556 if (regexec(field_regex, pattern, 3, matches, 0) != 0) {
557 PRINT_FAIL("Field reference expected\n");
558 goto err;
559 }
560
561 field_offset = find_field_offset(btf, pattern, matches);
562 if (field_offset < 0)
563 goto err;
564
565 pattern += matches[0].rm_eo;
566 acc_offset += field_offset;
567 }
568
569 text_next = match_number(text, acc_offset);
570 if (!text_next) {
571 PRINT_FAIL("No match for group offset %.*s (%d)\n",
572 (int)(pattern - group_start),
573 group_start,
574 acc_offset);
575 goto err;
576 }
577 text = text_next;
578 }
579
580 /* Match field reference:
581 * sk_buff::cb
582 */
583 if (regexec(field_regex, pattern, 3, matches, 0) == 0) {
584 int field_offset;
585 char *text_next;
586
587 field_offset = find_field_offset(btf, pattern, matches);
588 if (field_offset < 0)
589 goto err;
590
591 text_next = match_number(text, field_offset);
592 if (!text_next) {
593 PRINT_FAIL("No match for field offset %.*s (%d)\n",
594 (int)matches[0].rm_eo, pattern, field_offset);
595 goto err;
596 }
597
598 pattern += matches[0].rm_eo;
599 text = text_next;
600 continue;
601 }
602
603 /* If pattern points to identifier not followed by '::'
604 * skip the identifier to avoid n^2 application of the
605 * field reference rule.
606 */
607 if (regexec(ident_regex, pattern, 1, matches, 0) == 0) {
608 if (strncmp(pattern, text, matches[0].rm_eo) != 0)
609 goto err;
610
611 pattern += matches[0].rm_eo;
612 text += matches[0].rm_eo;
613 continue;
614 }
615
616 /* Match literally */
617 if (*pattern != *text)
618 goto err;
619
620 ++pattern;
621 ++text;
622 }
623
624 return true;
625
626err:
627 test__fail();
628 print_match_error(stdout, pattern_origin, text_origin, pattern, text);
629 return false;
630}
631
632struct prog_info {
633 char *prog_kind;
634 enum bpf_prog_type prog_type;
635 enum bpf_attach_type expected_attach_type;
636 struct bpf_insn *prog;
637 u32 prog_len;
638};
639
640static void match_program(struct btf *btf,
641 struct prog_info *pinfo,
642 char *pattern,
643 char *reg_map[][2],
644 bool skip_first_insn)
645{
646 struct bpf_insn *buf = NULL, *insn, *insn_end;
647 int err = 0, prog_fd = 0;
648 FILE *prog_out = NULL;
649 char insn_buf[64];
650 char *text = NULL;
651 __u32 cnt = 0;
652
653 text = calloc(MAX_PROG_TEXT_SZ, 1);
654 if (!text) {
655 PRINT_FAIL("Can't allocate %d bytes\n", MAX_PROG_TEXT_SZ);
656 goto out;
657 }
658
659 // TODO: log level
660 LIBBPF_OPTS(bpf_prog_load_opts, opts);
661 opts.log_buf = text;
662 opts.log_size = MAX_PROG_TEXT_SZ;
663 opts.log_level = 1 | 2 | 4;
664 opts.expected_attach_type = pinfo->expected_attach_type;
665
666 prog_fd = bpf_prog_load(pinfo->prog_type, NULL, "GPL",
667 pinfo->prog, pinfo->prog_len, &opts);
668 if (prog_fd < 0) {
669 PRINT_FAIL("Can't load program, errno %d (%s), verifier log:\n%s\n",
670 errno, strerror(errno), text);
671 goto out;
672 }
673
674 memset(text, 0, MAX_PROG_TEXT_SZ);
675
676 err = get_xlated_program(prog_fd, &buf, &cnt);
677 if (err) {
678 PRINT_FAIL("Can't load back BPF program\n");
679 goto out;
680 }
681
682 prog_out = fmemopen(text, MAX_PROG_TEXT_SZ - 1, "w");
683 if (!prog_out) {
684 PRINT_FAIL("Can't open memory stream\n");
685 goto out;
686 }
687 insn_end = buf + cnt;
688 insn = buf + (skip_first_insn ? 1 : 0);
689 while (insn < insn_end) {
690 insn = disasm_insn(insn, insn_buf, sizeof(insn_buf));
691 fprintf(prog_out, "%s\n", insn_buf);
692 }
693 fclose(prog_out);
694
695 ASSERT_TRUE(match_pattern(btf, pattern, text, reg_map),
696 pinfo->prog_kind);
697
698out:
699 if (prog_fd)
700 close(prog_fd);
701 free(buf);
702 free(text);
703}
704
705static void run_one_testcase(struct btf *btf, struct test_case *test)
706{
707 struct prog_info pinfo = {};
708 int bpf_sz;
709
710 if (!test__start_subtest(test->name))
711 return;
712
713 switch (test->field_sz) {
714 case 8:
715 bpf_sz = BPF_DW;
716 break;
717 case 4:
718 bpf_sz = BPF_W;
719 break;
720 case 2:
721 bpf_sz = BPF_H;
722 break;
723 case 1:
724 bpf_sz = BPF_B;
725 break;
726 default:
727 PRINT_FAIL("Unexpected field size: %d, want 8,4,2 or 1\n", test->field_sz);
728 return;
729 }
730
731 pinfo.prog_type = test->prog_type;
732 pinfo.expected_attach_type = test->expected_attach_type;
733
734 if (test->read) {
735 struct bpf_insn ldx_prog[] = {
736 BPF_LDX_MEM(bpf_sz, BPF_REG_2, BPF_REG_1, test->field_offset),
737 BPF_MOV64_IMM(BPF_REG_0, 0),
738 BPF_EXIT_INSN(),
739 };
740 char *reg_map[][2] = {
741 { "$ctx", "r1" },
742 { "$dst", "r2" },
743 {}
744 };
745
746 pinfo.prog_kind = "LDX";
747 pinfo.prog = ldx_prog;
748 pinfo.prog_len = ARRAY_SIZE(ldx_prog);
749 match_program(btf, &pinfo, test->read, reg_map, false);
750 }
751
752 if (test->write || test->write_st || test->write_stx) {
753 struct bpf_insn stx_prog[] = {
754 BPF_MOV64_IMM(BPF_REG_2, 0),
755 BPF_STX_MEM(bpf_sz, BPF_REG_1, BPF_REG_2, test->field_offset),
756 BPF_MOV64_IMM(BPF_REG_0, 0),
757 BPF_EXIT_INSN(),
758 };
759 char *stx_reg_map[][2] = {
760 { "$ctx", "r1" },
761 { "$src", "r2" },
762 {}
763 };
764 struct bpf_insn st_prog[] = {
765 BPF_ST_MEM(bpf_sz, BPF_REG_1, test->field_offset,
766 test->st_value.use ? test->st_value.value : 42),
767 BPF_MOV64_IMM(BPF_REG_0, 0),
768 BPF_EXIT_INSN(),
769 };
770 char *st_reg_map[][2] = {
771 { "$ctx", "r1" },
772 { "$src", "42" },
773 {}
774 };
775
776 if (test->write || test->write_stx) {
777 char *pattern = test->write_stx ? test->write_stx : test->write;
778
779 pinfo.prog_kind = "STX";
780 pinfo.prog = stx_prog;
781 pinfo.prog_len = ARRAY_SIZE(stx_prog);
782 match_program(btf, &pinfo, pattern, stx_reg_map, true);
783 }
784
785 if (test->write || test->write_st) {
786 char *pattern = test->write_st ? test->write_st : test->write;
787
788 pinfo.prog_kind = "ST";
789 pinfo.prog = st_prog;
790 pinfo.prog_len = ARRAY_SIZE(st_prog);
791 match_program(btf, &pinfo, pattern, st_reg_map, false);
792 }
793 }
794
795 test__end_subtest();
796}
797
798void test_ctx_rewrite(void)
799{
800 struct btf *btf;
801 int i;
802
803 field_regex = compile_regex("^([[:alpha:]_][[:alnum:]_]+)::([[:alpha:]_][[:alnum:]_]+)");
804 ident_regex = compile_regex("^[[:alpha:]_][[:alnum:]_]+");
805 if (!field_regex || !ident_regex)
806 return;
807
808 btf = btf__load_vmlinux_btf();
809 if (!btf) {
810 PRINT_FAIL("Can't load vmlinux BTF, errno %d (%s)\n", errno, strerror(errno));
811 goto out;
812 }
813
814 for (i = 0; i < ARRAY_SIZE(test_cases); ++i)
815 run_one_testcase(btf, &test_cases[i]);
816
817out:
818 btf__free(btf);
819 free_regex(field_regex);
820 free_regex(ident_regex);
821}