forked from torvalds/linux
-
Notifications
You must be signed in to change notification settings - Fork 0
/
bpf_dbg.c
1398 lines (1215 loc) · 28.2 KB
/
bpf_dbg.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
* Minimal BPF debugger
*
* Minimal BPF debugger that mimics the kernel's engine (w/o extensions)
* and allows for single stepping through selected packets from a pcap
* with a provided user filter in order to facilitate verification of a
* BPF program. Besides others, this is useful to verify BPF programs
* before attaching to a live system, and can be used in socket filters,
* cls_bpf, xt_bpf, team driver and e.g. PTP code; in particular when a
* single more complex BPF program is being used. Reasons for a more
* complex BPF program are likely primarily to optimize execution time
* for making a verdict when multiple simple BPF programs are combined
* into one in order to prevent parsing same headers multiple times.
*
* More on how to debug BPF opcodes see Documentation/networking/filter.txt
* which is the main document on BPF. Mini howto for getting started:
*
* 1) `./bpf_dbg` to enter the shell (shell cmds denoted with '>'):
* 2) > load bpf 6,40 0 0 12,21 0 3 20... (output from `bpf_asm` or
* `tcpdump -iem1 -ddd port 22 | tr '\n' ','` to load as filter)
* 3) > load pcap foo.pcap
* 4) > run <n>/disassemble/dump/quit (self-explanatory)
* 5) > breakpoint 2 (sets bp at loaded BPF insns 2, do `run` then;
* multiple bps can be set, of course, a call to `breakpoint`
* w/o args shows currently loaded bps, `breakpoint reset` for
* resetting all breakpoints)
* 6) > select 3 (`run` etc will start from the 3rd packet in the pcap)
* 7) > step [-<n>, +<n>] (performs single stepping through the BPF)
*
* Copyright 2013 Daniel Borkmann <borkmann@redhat.com>
* Licensed under the GNU General Public License, version 2.0 (GPLv2)
*/
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <ctype.h>
#include <stdbool.h>
#include <stdarg.h>
#include <setjmp.h>
#include <linux/filter.h>
#include <linux/if_packet.h>
#include <readline/readline.h>
#include <readline/history.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <errno.h>
#include <signal.h>
#include <arpa/inet.h>
#include <net/ethernet.h>
#define TCPDUMP_MAGIC 0xa1b2c3d4
#define BPF_LDX_B (BPF_LDX | BPF_B)
#define BPF_LDX_W (BPF_LDX | BPF_W)
#define BPF_JMP_JA (BPF_JMP | BPF_JA)
#define BPF_JMP_JEQ (BPF_JMP | BPF_JEQ)
#define BPF_JMP_JGT (BPF_JMP | BPF_JGT)
#define BPF_JMP_JGE (BPF_JMP | BPF_JGE)
#define BPF_JMP_JSET (BPF_JMP | BPF_JSET)
#define BPF_ALU_ADD (BPF_ALU | BPF_ADD)
#define BPF_ALU_SUB (BPF_ALU | BPF_SUB)
#define BPF_ALU_MUL (BPF_ALU | BPF_MUL)
#define BPF_ALU_DIV (BPF_ALU | BPF_DIV)
#define BPF_ALU_MOD (BPF_ALU | BPF_MOD)
#define BPF_ALU_NEG (BPF_ALU | BPF_NEG)
#define BPF_ALU_AND (BPF_ALU | BPF_AND)
#define BPF_ALU_OR (BPF_ALU | BPF_OR)
#define BPF_ALU_XOR (BPF_ALU | BPF_XOR)
#define BPF_ALU_LSH (BPF_ALU | BPF_LSH)
#define BPF_ALU_RSH (BPF_ALU | BPF_RSH)
#define BPF_MISC_TAX (BPF_MISC | BPF_TAX)
#define BPF_MISC_TXA (BPF_MISC | BPF_TXA)
#define BPF_LD_B (BPF_LD | BPF_B)
#define BPF_LD_H (BPF_LD | BPF_H)
#define BPF_LD_W (BPF_LD | BPF_W)
#ifndef array_size
# define array_size(x) (sizeof(x) / sizeof((x)[0]))
#endif
#ifndef __check_format_printf
# define __check_format_printf(pos_fmtstr, pos_fmtargs) \
__attribute__ ((format (printf, (pos_fmtstr), (pos_fmtargs))))
#endif
enum {
CMD_OK,
CMD_ERR,
CMD_EX,
};
struct shell_cmd {
const char *name;
int (*func)(char *args);
};
struct pcap_filehdr {
uint32_t magic;
uint16_t version_major;
uint16_t version_minor;
int32_t thiszone;
uint32_t sigfigs;
uint32_t snaplen;
uint32_t linktype;
};
struct pcap_timeval {
int32_t tv_sec;
int32_t tv_usec;
};
struct pcap_pkthdr {
struct pcap_timeval ts;
uint32_t caplen;
uint32_t len;
};
struct bpf_regs {
uint32_t A;
uint32_t X;
uint32_t M[BPF_MEMWORDS];
uint32_t R;
bool Rs;
uint16_t Pc;
};
static struct sock_filter bpf_image[BPF_MAXINSNS + 1];
static unsigned int bpf_prog_len;
static int bpf_breakpoints[64];
static struct bpf_regs bpf_regs[BPF_MAXINSNS + 1];
static struct bpf_regs bpf_curr;
static unsigned int bpf_regs_len;
static int pcap_fd = -1;
static unsigned int pcap_packet;
static size_t pcap_map_size;
static char *pcap_ptr_va_start, *pcap_ptr_va_curr;
static const char * const op_table[] = {
[BPF_ST] = "st",
[BPF_STX] = "stx",
[BPF_LD_B] = "ldb",
[BPF_LD_H] = "ldh",
[BPF_LD_W] = "ld",
[BPF_LDX] = "ldx",
[BPF_LDX_B] = "ldxb",
[BPF_JMP_JA] = "ja",
[BPF_JMP_JEQ] = "jeq",
[BPF_JMP_JGT] = "jgt",
[BPF_JMP_JGE] = "jge",
[BPF_JMP_JSET] = "jset",
[BPF_ALU_ADD] = "add",
[BPF_ALU_SUB] = "sub",
[BPF_ALU_MUL] = "mul",
[BPF_ALU_DIV] = "div",
[BPF_ALU_MOD] = "mod",
[BPF_ALU_NEG] = "neg",
[BPF_ALU_AND] = "and",
[BPF_ALU_OR] = "or",
[BPF_ALU_XOR] = "xor",
[BPF_ALU_LSH] = "lsh",
[BPF_ALU_RSH] = "rsh",
[BPF_MISC_TAX] = "tax",
[BPF_MISC_TXA] = "txa",
[BPF_RET] = "ret",
};
static __check_format_printf(1, 2) int rl_printf(const char *fmt, ...)
{
int ret;
va_list vl;
va_start(vl, fmt);
ret = vfprintf(rl_outstream, fmt, vl);
va_end(vl);
return ret;
}
static int matches(const char *cmd, const char *pattern)
{
int len = strlen(cmd);
if (len > strlen(pattern))
return -1;
return memcmp(pattern, cmd, len);
}
static void hex_dump(const uint8_t *buf, size_t len)
{
int i;
rl_printf("%3u: ", 0);
for (i = 0; i < len; i++) {
if (i && !(i % 16))
rl_printf("\n%3u: ", i);
rl_printf("%02x ", buf[i]);
}
rl_printf("\n");
}
static bool bpf_prog_loaded(void)
{
if (bpf_prog_len == 0)
rl_printf("no bpf program loaded!\n");
return bpf_prog_len > 0;
}
static void bpf_disasm(const struct sock_filter f, unsigned int i)
{
const char *op, *fmt;
int val = f.k;
char buf[256];
switch (f.code) {
case BPF_RET | BPF_K:
op = op_table[BPF_RET];
fmt = "#%#x";
break;
case BPF_RET | BPF_A:
op = op_table[BPF_RET];
fmt = "a";
break;
case BPF_RET | BPF_X:
op = op_table[BPF_RET];
fmt = "x";
break;
case BPF_MISC_TAX:
op = op_table[BPF_MISC_TAX];
fmt = "";
break;
case BPF_MISC_TXA:
op = op_table[BPF_MISC_TXA];
fmt = "";
break;
case BPF_ST:
op = op_table[BPF_ST];
fmt = "M[%d]";
break;
case BPF_STX:
op = op_table[BPF_STX];
fmt = "M[%d]";
break;
case BPF_LD_W | BPF_ABS:
op = op_table[BPF_LD_W];
fmt = "[%d]";
break;
case BPF_LD_H | BPF_ABS:
op = op_table[BPF_LD_H];
fmt = "[%d]";
break;
case BPF_LD_B | BPF_ABS:
op = op_table[BPF_LD_B];
fmt = "[%d]";
break;
case BPF_LD_W | BPF_LEN:
op = op_table[BPF_LD_W];
fmt = "#len";
break;
case BPF_LD_W | BPF_IND:
op = op_table[BPF_LD_W];
fmt = "[x+%d]";
break;
case BPF_LD_H | BPF_IND:
op = op_table[BPF_LD_H];
fmt = "[x+%d]";
break;
case BPF_LD_B | BPF_IND:
op = op_table[BPF_LD_B];
fmt = "[x+%d]";
break;
case BPF_LD | BPF_IMM:
op = op_table[BPF_LD_W];
fmt = "#%#x";
break;
case BPF_LDX | BPF_IMM:
op = op_table[BPF_LDX];
fmt = "#%#x";
break;
case BPF_LDX_B | BPF_MSH:
op = op_table[BPF_LDX_B];
fmt = "4*([%d]&0xf)";
break;
case BPF_LD | BPF_MEM:
op = op_table[BPF_LD_W];
fmt = "M[%d]";
break;
case BPF_LDX | BPF_MEM:
op = op_table[BPF_LDX];
fmt = "M[%d]";
break;
case BPF_JMP_JA:
op = op_table[BPF_JMP_JA];
fmt = "%d";
val = i + 1 + f.k;
break;
case BPF_JMP_JGT | BPF_X:
op = op_table[BPF_JMP_JGT];
fmt = "x";
break;
case BPF_JMP_JGT | BPF_K:
op = op_table[BPF_JMP_JGT];
fmt = "#%#x";
break;
case BPF_JMP_JGE | BPF_X:
op = op_table[BPF_JMP_JGE];
fmt = "x";
break;
case BPF_JMP_JGE | BPF_K:
op = op_table[BPF_JMP_JGE];
fmt = "#%#x";
break;
case BPF_JMP_JEQ | BPF_X:
op = op_table[BPF_JMP_JEQ];
fmt = "x";
break;
case BPF_JMP_JEQ | BPF_K:
op = op_table[BPF_JMP_JEQ];
fmt = "#%#x";
break;
case BPF_JMP_JSET | BPF_X:
op = op_table[BPF_JMP_JSET];
fmt = "x";
break;
case BPF_JMP_JSET | BPF_K:
op = op_table[BPF_JMP_JSET];
fmt = "#%#x";
break;
case BPF_ALU_NEG:
op = op_table[BPF_ALU_NEG];
fmt = "";
break;
case BPF_ALU_LSH | BPF_X:
op = op_table[BPF_ALU_LSH];
fmt = "x";
break;
case BPF_ALU_LSH | BPF_K:
op = op_table[BPF_ALU_LSH];
fmt = "#%d";
break;
case BPF_ALU_RSH | BPF_X:
op = op_table[BPF_ALU_RSH];
fmt = "x";
break;
case BPF_ALU_RSH | BPF_K:
op = op_table[BPF_ALU_RSH];
fmt = "#%d";
break;
case BPF_ALU_ADD | BPF_X:
op = op_table[BPF_ALU_ADD];
fmt = "x";
break;
case BPF_ALU_ADD | BPF_K:
op = op_table[BPF_ALU_ADD];
fmt = "#%d";
break;
case BPF_ALU_SUB | BPF_X:
op = op_table[BPF_ALU_SUB];
fmt = "x";
break;
case BPF_ALU_SUB | BPF_K:
op = op_table[BPF_ALU_SUB];
fmt = "#%d";
break;
case BPF_ALU_MUL | BPF_X:
op = op_table[BPF_ALU_MUL];
fmt = "x";
break;
case BPF_ALU_MUL | BPF_K:
op = op_table[BPF_ALU_MUL];
fmt = "#%d";
break;
case BPF_ALU_DIV | BPF_X:
op = op_table[BPF_ALU_DIV];
fmt = "x";
break;
case BPF_ALU_DIV | BPF_K:
op = op_table[BPF_ALU_DIV];
fmt = "#%d";
break;
case BPF_ALU_MOD | BPF_X:
op = op_table[BPF_ALU_MOD];
fmt = "x";
break;
case BPF_ALU_MOD | BPF_K:
op = op_table[BPF_ALU_MOD];
fmt = "#%d";
break;
case BPF_ALU_AND | BPF_X:
op = op_table[BPF_ALU_AND];
fmt = "x";
break;
case BPF_ALU_AND | BPF_K:
op = op_table[BPF_ALU_AND];
fmt = "#%#x";
break;
case BPF_ALU_OR | BPF_X:
op = op_table[BPF_ALU_OR];
fmt = "x";
break;
case BPF_ALU_OR | BPF_K:
op = op_table[BPF_ALU_OR];
fmt = "#%#x";
break;
case BPF_ALU_XOR | BPF_X:
op = op_table[BPF_ALU_XOR];
fmt = "x";
break;
case BPF_ALU_XOR | BPF_K:
op = op_table[BPF_ALU_XOR];
fmt = "#%#x";
break;
default:
op = "nosup";
fmt = "%#x";
val = f.code;
break;
}
memset(buf, 0, sizeof(buf));
snprintf(buf, sizeof(buf), fmt, val);
buf[sizeof(buf) - 1] = 0;
if ((BPF_CLASS(f.code) == BPF_JMP && BPF_OP(f.code) != BPF_JA))
rl_printf("l%d:\t%s %s, l%d, l%d\n", i, op, buf,
i + 1 + f.jt, i + 1 + f.jf);
else
rl_printf("l%d:\t%s %s\n", i, op, buf);
}
static void bpf_dump_curr(struct bpf_regs *r, struct sock_filter *f)
{
int i, m = 0;
rl_printf("pc: [%u]\n", r->Pc);
rl_printf("code: [%u] jt[%u] jf[%u] k[%u]\n",
f->code, f->jt, f->jf, f->k);
rl_printf("curr: ");
bpf_disasm(*f, r->Pc);
if (f->jt || f->jf) {
rl_printf("jt: ");
bpf_disasm(*(f + f->jt + 1), r->Pc + f->jt + 1);
rl_printf("jf: ");
bpf_disasm(*(f + f->jf + 1), r->Pc + f->jf + 1);
}
rl_printf("A: [%#08x][%u]\n", r->A, r->A);
rl_printf("X: [%#08x][%u]\n", r->X, r->X);
if (r->Rs)
rl_printf("ret: [%#08x][%u]!\n", r->R, r->R);
for (i = 0; i < BPF_MEMWORDS; i++) {
if (r->M[i]) {
m++;
rl_printf("M[%d]: [%#08x][%u]\n", i, r->M[i], r->M[i]);
}
}
if (m == 0)
rl_printf("M[0,%d]: [%#08x][%u]\n", BPF_MEMWORDS - 1, 0, 0);
}
static void bpf_dump_pkt(uint8_t *pkt, uint32_t pkt_caplen, uint32_t pkt_len)
{
if (pkt_caplen != pkt_len)
rl_printf("cap: %u, len: %u\n", pkt_caplen, pkt_len);
else
rl_printf("len: %u\n", pkt_len);
hex_dump(pkt, pkt_caplen);
}
static void bpf_disasm_all(const struct sock_filter *f, unsigned int len)
{
unsigned int i;
for (i = 0; i < len; i++)
bpf_disasm(f[i], i);
}
static void bpf_dump_all(const struct sock_filter *f, unsigned int len)
{
unsigned int i;
rl_printf("/* { op, jt, jf, k }, */\n");
for (i = 0; i < len; i++)
rl_printf("{ %#04x, %2u, %2u, %#010x },\n",
f[i].code, f[i].jt, f[i].jf, f[i].k);
}
static bool bpf_runnable(struct sock_filter *f, unsigned int len)
{
int sock, ret, i;
struct sock_fprog bpf = {
.filter = f,
.len = len,
};
sock = socket(AF_INET, SOCK_DGRAM, 0);
if (sock < 0) {
rl_printf("cannot open socket!\n");
return false;
}
ret = setsockopt(sock, SOL_SOCKET, SO_ATTACH_FILTER, &bpf, sizeof(bpf));
close(sock);
if (ret < 0) {
rl_printf("program not allowed to run by kernel!\n");
return false;
}
for (i = 0; i < len; i++) {
if (BPF_CLASS(f[i].code) == BPF_LD &&
f[i].k > SKF_AD_OFF) {
rl_printf("extensions currently not supported!\n");
return false;
}
}
return true;
}
static void bpf_reset_breakpoints(void)
{
int i;
for (i = 0; i < array_size(bpf_breakpoints); i++)
bpf_breakpoints[i] = -1;
}
static void bpf_set_breakpoints(unsigned int where)
{
int i;
bool set = false;
for (i = 0; i < array_size(bpf_breakpoints); i++) {
if (bpf_breakpoints[i] == (int) where) {
rl_printf("breakpoint already set!\n");
set = true;
break;
}
if (bpf_breakpoints[i] == -1 && set == false) {
bpf_breakpoints[i] = where;
set = true;
}
}
if (!set)
rl_printf("too many breakpoints set, reset first!\n");
}
static void bpf_dump_breakpoints(void)
{
int i;
rl_printf("breakpoints: ");
for (i = 0; i < array_size(bpf_breakpoints); i++) {
if (bpf_breakpoints[i] < 0)
continue;
rl_printf("%d ", bpf_breakpoints[i]);
}
rl_printf("\n");
}
static void bpf_reset(void)
{
bpf_regs_len = 0;
memset(bpf_regs, 0, sizeof(bpf_regs));
memset(&bpf_curr, 0, sizeof(bpf_curr));
}
static void bpf_safe_regs(void)
{
memcpy(&bpf_regs[bpf_regs_len++], &bpf_curr, sizeof(bpf_curr));
}
static bool bpf_restore_regs(int off)
{
unsigned int index = bpf_regs_len - 1 + off;
if (index == 0) {
bpf_reset();
return true;
} else if (index < bpf_regs_len) {
memcpy(&bpf_curr, &bpf_regs[index], sizeof(bpf_curr));
bpf_regs_len = index;
return true;
} else {
rl_printf("reached bottom of register history stack!\n");
return false;
}
}
static uint32_t extract_u32(uint8_t *pkt, uint32_t off)
{
uint32_t r;
memcpy(&r, &pkt[off], sizeof(r));
return ntohl(r);
}
static uint16_t extract_u16(uint8_t *pkt, uint32_t off)
{
uint16_t r;
memcpy(&r, &pkt[off], sizeof(r));
return ntohs(r);
}
static uint8_t extract_u8(uint8_t *pkt, uint32_t off)
{
return pkt[off];
}
static void set_return(struct bpf_regs *r)
{
r->R = 0;
r->Rs = true;
}
static void bpf_single_step(struct bpf_regs *r, struct sock_filter *f,
uint8_t *pkt, uint32_t pkt_caplen,
uint32_t pkt_len)
{
uint32_t K = f->k;
int d;
switch (f->code) {
case BPF_RET | BPF_K:
r->R = K;
r->Rs = true;
break;
case BPF_RET | BPF_A:
r->R = r->A;
r->Rs = true;
break;
case BPF_RET | BPF_X:
r->R = r->X;
r->Rs = true;
break;
case BPF_MISC_TAX:
r->X = r->A;
break;
case BPF_MISC_TXA:
r->A = r->X;
break;
case BPF_ST:
r->M[K] = r->A;
break;
case BPF_STX:
r->M[K] = r->X;
break;
case BPF_LD_W | BPF_ABS:
d = pkt_caplen - K;
if (d >= sizeof(uint32_t))
r->A = extract_u32(pkt, K);
else
set_return(r);
break;
case BPF_LD_H | BPF_ABS:
d = pkt_caplen - K;
if (d >= sizeof(uint16_t))
r->A = extract_u16(pkt, K);
else
set_return(r);
break;
case BPF_LD_B | BPF_ABS:
d = pkt_caplen - K;
if (d >= sizeof(uint8_t))
r->A = extract_u8(pkt, K);
else
set_return(r);
break;
case BPF_LD_W | BPF_IND:
d = pkt_caplen - (r->X + K);
if (d >= sizeof(uint32_t))
r->A = extract_u32(pkt, r->X + K);
break;
case BPF_LD_H | BPF_IND:
d = pkt_caplen - (r->X + K);
if (d >= sizeof(uint16_t))
r->A = extract_u16(pkt, r->X + K);
else
set_return(r);
break;
case BPF_LD_B | BPF_IND:
d = pkt_caplen - (r->X + K);
if (d >= sizeof(uint8_t))
r->A = extract_u8(pkt, r->X + K);
else
set_return(r);
break;
case BPF_LDX_B | BPF_MSH:
d = pkt_caplen - K;
if (d >= sizeof(uint8_t)) {
r->X = extract_u8(pkt, K);
r->X = (r->X & 0xf) << 2;
} else
set_return(r);
break;
case BPF_LD_W | BPF_LEN:
r->A = pkt_len;
break;
case BPF_LDX_W | BPF_LEN:
r->A = pkt_len;
break;
case BPF_LD | BPF_IMM:
r->A = K;
break;
case BPF_LDX | BPF_IMM:
r->X = K;
break;
case BPF_LD | BPF_MEM:
r->A = r->M[K];
break;
case BPF_LDX | BPF_MEM:
r->X = r->M[K];
break;
case BPF_JMP_JA:
r->Pc += K;
break;
case BPF_JMP_JGT | BPF_X:
r->Pc += r->A > r->X ? f->jt : f->jf;
break;
case BPF_JMP_JGT | BPF_K:
r->Pc += r->A > K ? f->jt : f->jf;
break;
case BPF_JMP_JGE | BPF_X:
r->Pc += r->A >= r->X ? f->jt : f->jf;
break;
case BPF_JMP_JGE | BPF_K:
r->Pc += r->A >= K ? f->jt : f->jf;
break;
case BPF_JMP_JEQ | BPF_X:
r->Pc += r->A == r->X ? f->jt : f->jf;
break;
case BPF_JMP_JEQ | BPF_K:
r->Pc += r->A == K ? f->jt : f->jf;
break;
case BPF_JMP_JSET | BPF_X:
r->Pc += r->A & r->X ? f->jt : f->jf;
break;
case BPF_JMP_JSET | BPF_K:
r->Pc += r->A & K ? f->jt : f->jf;
break;
case BPF_ALU_NEG:
r->A = -r->A;
break;
case BPF_ALU_LSH | BPF_X:
r->A <<= r->X;
break;
case BPF_ALU_LSH | BPF_K:
r->A <<= K;
break;
case BPF_ALU_RSH | BPF_X:
r->A >>= r->X;
break;
case BPF_ALU_RSH | BPF_K:
r->A >>= K;
break;
case BPF_ALU_ADD | BPF_X:
r->A += r->X;
break;
case BPF_ALU_ADD | BPF_K:
r->A += K;
break;
case BPF_ALU_SUB | BPF_X:
r->A -= r->X;
break;
case BPF_ALU_SUB | BPF_K:
r->A -= K;
break;
case BPF_ALU_MUL | BPF_X:
r->A *= r->X;
break;
case BPF_ALU_MUL | BPF_K:
r->A *= K;
break;
case BPF_ALU_DIV | BPF_X:
case BPF_ALU_MOD | BPF_X:
if (r->X == 0) {
set_return(r);
break;
}
goto do_div;
case BPF_ALU_DIV | BPF_K:
case BPF_ALU_MOD | BPF_K:
if (K == 0) {
set_return(r);
break;
}
do_div:
switch (f->code) {
case BPF_ALU_DIV | BPF_X:
r->A /= r->X;
break;
case BPF_ALU_DIV | BPF_K:
r->A /= K;
break;
case BPF_ALU_MOD | BPF_X:
r->A %= r->X;
break;
case BPF_ALU_MOD | BPF_K:
r->A %= K;
break;
}
break;
case BPF_ALU_AND | BPF_X:
r->A &= r->X;
break;
case BPF_ALU_AND | BPF_K:
r->A &= K;
break;
case BPF_ALU_OR | BPF_X:
r->A |= r->X;
break;
case BPF_ALU_OR | BPF_K:
r->A |= K;
break;
case BPF_ALU_XOR | BPF_X:
r->A ^= r->X;
break;
case BPF_ALU_XOR | BPF_K:
r->A ^= K;
break;
}
}
static bool bpf_pc_has_breakpoint(uint16_t pc)
{
int i;
for (i = 0; i < array_size(bpf_breakpoints); i++) {
if (bpf_breakpoints[i] < 0)
continue;
if (bpf_breakpoints[i] == pc)
return true;
}
return false;
}
static bool bpf_handle_breakpoint(struct bpf_regs *r, struct sock_filter *f,
uint8_t *pkt, uint32_t pkt_caplen,
uint32_t pkt_len)
{
rl_printf("-- register dump --\n");
bpf_dump_curr(r, &f[r->Pc]);
rl_printf("-- packet dump --\n");
bpf_dump_pkt(pkt, pkt_caplen, pkt_len);
rl_printf("(breakpoint)\n");
return true;
}
static int bpf_run_all(struct sock_filter *f, uint16_t bpf_len, uint8_t *pkt,
uint32_t pkt_caplen, uint32_t pkt_len)
{
bool stop = false;
while (bpf_curr.Rs == false && stop == false) {
bpf_safe_regs();
if (bpf_pc_has_breakpoint(bpf_curr.Pc))
stop = bpf_handle_breakpoint(&bpf_curr, f, pkt,
pkt_caplen, pkt_len);
bpf_single_step(&bpf_curr, &f[bpf_curr.Pc], pkt, pkt_caplen,
pkt_len);
bpf_curr.Pc++;
}
return stop ? -1 : bpf_curr.R;
}
static int bpf_run_stepping(struct sock_filter *f, uint16_t bpf_len,
uint8_t *pkt, uint32_t pkt_caplen,
uint32_t pkt_len, int next)
{
bool stop = false;
int i = 1;
while (bpf_curr.Rs == false && stop == false) {
bpf_safe_regs();
if (i++ == next)
stop = bpf_handle_breakpoint(&bpf_curr, f, pkt,
pkt_caplen, pkt_len);
bpf_single_step(&bpf_curr, &f[bpf_curr.Pc], pkt, pkt_caplen,
pkt_len);
bpf_curr.Pc++;
}
return stop ? -1 : bpf_curr.R;
}
static bool pcap_loaded(void)
{
if (pcap_fd < 0)
rl_printf("no pcap file loaded!\n");
return pcap_fd >= 0;
}
static struct pcap_pkthdr *pcap_curr_pkt(void)
{
return (void *) pcap_ptr_va_curr;
}
static bool pcap_next_pkt(void)
{
struct pcap_pkthdr *hdr = pcap_curr_pkt();
if (pcap_ptr_va_curr + sizeof(*hdr) -
pcap_ptr_va_start >= pcap_map_size)
return false;
if (hdr->caplen == 0 || hdr->len == 0 || hdr->caplen > hdr->len)
return false;
if (pcap_ptr_va_curr + sizeof(*hdr) + hdr->caplen -
pcap_ptr_va_start >= pcap_map_size)
return false;
pcap_ptr_va_curr += (sizeof(*hdr) + hdr->caplen);
return true;
}
static void pcap_reset_pkt(void)
{
pcap_ptr_va_curr = pcap_ptr_va_start + sizeof(struct pcap_filehdr);
}
static int try_load_pcap(const char *file)
{
struct pcap_filehdr *hdr;
struct stat sb;
int ret;
pcap_fd = open(file, O_RDONLY);
if (pcap_fd < 0) {
rl_printf("cannot open pcap [%s]!\n", strerror(errno));
return CMD_ERR;
}
ret = fstat(pcap_fd, &sb);
if (ret < 0) {
rl_printf("cannot fstat pcap file!\n");
return CMD_ERR;
}
if (!S_ISREG(sb.st_mode)) {
rl_printf("not a regular pcap file, duh!\n");
return CMD_ERR;
}
pcap_map_size = sb.st_size;
if (pcap_map_size <= sizeof(struct pcap_filehdr)) {
rl_printf("pcap file too small!\n");
return CMD_ERR;
}
pcap_ptr_va_start = mmap(NULL, pcap_map_size, PROT_READ,
MAP_SHARED | MAP_LOCKED, pcap_fd, 0);
if (pcap_ptr_va_start == MAP_FAILED) {
rl_printf("mmap of file failed!");
return CMD_ERR;
}
hdr = (void *) pcap_ptr_va_start;
if (hdr->magic != TCPDUMP_MAGIC) {
rl_printf("wrong pcap magic!\n");
return CMD_ERR;
}
pcap_reset_pkt();
return CMD_OK;
}
static void try_close_pcap(void)
{
if (pcap_fd >= 0) {
munmap(pcap_ptr_va_start, pcap_map_size);
close(pcap_fd);
pcap_ptr_va_start = pcap_ptr_va_curr = NULL;
pcap_map_size = 0;
pcap_packet = 0;
pcap_fd = -1;