forked from the-tcpdump-group/libpcap
-
Notifications
You must be signed in to change notification settings - Fork 0
/
gencode.c
10066 lines (8738 loc) · 258 KB
/
gencode.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
/*#define CHASE_CHAIN*/
/*
* Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code distributions
* retain the above copyright notice and this paragraph in its entirety, (2)
* distributions including binary code include the above copyright notice and
* this paragraph in its entirety in the documentation or other materials
* provided with the distribution, and (3) all advertising materials mentioning
* features or use of this software display the following acknowledgement:
* ``This product includes software developed by the University of California,
* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
* the University nor the names of its contributors may be used to endorse
* or promote products derived from this software without specific prior
* written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <pcap-types.h>
#ifdef _WIN32
#include <ws2tcpip.h>
#else
#include <sys/socket.h>
#ifdef __NetBSD__
#include <sys/param.h>
#endif
#include <netinet/in.h>
#include <arpa/inet.h>
#endif /* _WIN32 */
#include <stdlib.h>
#include <string.h>
#include <memory.h>
#include <setjmp.h>
#include <stdarg.h>
#ifdef MSDOS
#include "pcap-dos.h"
#endif
#ifdef HAVE_NET_PFVAR_H
/*
* In NetBSD <net/if.h> includes <net/dlt.h>, which is an older version of
* "pcap/dlt.h" with a lower value of DLT_MATCHING_MAX. Include the headers
* below before "pcap-int.h", which eventually includes "pcap/dlt.h", which
* redefines DLT_MATCHING_MAX from what this version of NetBSD has to what
* this version of libpcap has.
*/
#include <sys/socket.h>
#include <net/if.h>
#include <net/pfvar.h>
#include <net/if_pflog.h>
#endif /* HAVE_NET_PFVAR_H */
#include "pcap-int.h"
#include "extract.h"
#include "ethertype.h"
#include "nlpid.h"
#include "llc.h"
#include "gencode.h"
#include "ieee80211.h"
#include "atmuni31.h"
#include "sunatmpos.h"
#include "ppp.h"
#include "pcap/sll.h"
#include "pcap/ipnet.h"
#include "arcnet.h"
#include "diag-control.h"
#include "scanner.h"
#if defined(linux)
#include <linux/types.h>
#include <linux/if_packet.h>
#include <linux/filter.h>
#endif
#ifndef offsetof
#define offsetof(s, e) ((size_t)&((s *)0)->e)
#endif
#ifdef _WIN32
#ifdef INET6
#if defined(__MINGW32__) && defined(DEFINE_ADDITIONAL_IPV6_STUFF)
/* IPv6 address */
struct in6_addr
{
union
{
uint8_t u6_addr8[16];
uint16_t u6_addr16[8];
uint32_t u6_addr32[4];
} in6_u;
#define s6_addr in6_u.u6_addr8
#define s6_addr16 in6_u.u6_addr16
#define s6_addr32 in6_u.u6_addr32
#define s6_addr64 in6_u.u6_addr64
};
typedef unsigned short sa_family_t;
#define __SOCKADDR_COMMON(sa_prefix) \
sa_family_t sa_prefix##family
/* Ditto, for IPv6. */
struct sockaddr_in6
{
__SOCKADDR_COMMON (sin6_);
uint16_t sin6_port; /* Transport layer port # */
uint32_t sin6_flowinfo; /* IPv6 flow information */
struct in6_addr sin6_addr; /* IPv6 address */
};
#ifndef EAI_ADDRFAMILY
struct addrinfo {
int ai_flags; /* AI_PASSIVE, AI_CANONNAME */
int ai_family; /* PF_xxx */
int ai_socktype; /* SOCK_xxx */
int ai_protocol; /* 0 or IPPROTO_xxx for IPv4 and IPv6 */
size_t ai_addrlen; /* length of ai_addr */
char *ai_canonname; /* canonical name for hostname */
struct sockaddr *ai_addr; /* binary address */
struct addrinfo *ai_next; /* next structure in linked list */
};
#endif /* EAI_ADDRFAMILY */
#endif /* defined(__MINGW32__) && defined(DEFINE_ADDITIONAL_IPV6_STUFF) */
#endif /* INET6 */
#else /* _WIN32 */
#include <netdb.h> /* for "struct addrinfo" */
#endif /* _WIN32 */
#include <pcap/namedb.h>
#include "nametoaddr.h"
#define ETHERMTU 1500
#ifndef IPPROTO_HOPOPTS
#define IPPROTO_HOPOPTS 0
#endif
#ifndef IPPROTO_ROUTING
#define IPPROTO_ROUTING 43
#endif
#ifndef IPPROTO_FRAGMENT
#define IPPROTO_FRAGMENT 44
#endif
#ifndef IPPROTO_DSTOPTS
#define IPPROTO_DSTOPTS 60
#endif
#ifndef IPPROTO_SCTP
#define IPPROTO_SCTP 132
#endif
#define GENEVE_PORT 6081
#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif
#define JMP(c) ((c)|BPF_JMP|BPF_K)
/*
* "Push" the current value of the link-layer header type and link-layer
* header offset onto a "stack", and set a new value. (It's not a
* full-blown stack; we keep only the top two items.)
*/
#define PUSH_LINKHDR(cs, new_linktype, new_is_variable, new_constant_part, new_reg) \
{ \
(cs)->prevlinktype = (cs)->linktype; \
(cs)->off_prevlinkhdr = (cs)->off_linkhdr; \
(cs)->linktype = (new_linktype); \
(cs)->off_linkhdr.is_variable = (new_is_variable); \
(cs)->off_linkhdr.constant_part = (new_constant_part); \
(cs)->off_linkhdr.reg = (new_reg); \
(cs)->is_geneve = 0; \
}
/*
* Offset "not set" value.
*/
#define OFFSET_NOT_SET 0xffffffffU
/*
* Absolute offsets, which are offsets from the beginning of the raw
* packet data, are, in the general case, the sum of a variable value
* and a constant value; the variable value may be absent, in which
* case the offset is only the constant value, and the constant value
* may be zero, in which case the offset is only the variable value.
*
* bpf_abs_offset is a structure containing all that information:
*
* is_variable is 1 if there's a variable part.
*
* constant_part is the constant part of the value, possibly zero;
*
* if is_variable is 1, reg is the register number for a register
* containing the variable value if the register has been assigned,
* and -1 otherwise.
*/
typedef struct {
int is_variable;
u_int constant_part;
int reg;
} bpf_abs_offset;
/*
* Value passed to gen_load_a() to indicate what the offset argument
* is relative to the beginning of.
*/
enum e_offrel {
OR_PACKET, /* full packet data */
OR_LINKHDR, /* link-layer header */
OR_PREVLINKHDR, /* previous link-layer header */
OR_LLC, /* 802.2 LLC header */
OR_PREVMPLSHDR, /* previous MPLS header */
OR_LINKTYPE, /* link-layer type */
OR_LINKPL, /* link-layer payload */
OR_LINKPL_NOSNAP, /* link-layer payload, with no SNAP header at the link layer */
OR_TRAN_IPV4, /* transport-layer header, with IPv4 network layer */
OR_TRAN_IPV6 /* transport-layer header, with IPv6 network layer */
};
/*
* We divy out chunks of memory rather than call malloc each time so
* we don't have to worry about leaking memory. It's probably
* not a big deal if all this memory was wasted but if this ever
* goes into a library that would probably not be a good idea.
*
* XXX - this *is* in a library....
*/
#define NCHUNKS 16
#define CHUNK0SIZE 1024
struct chunk {
size_t n_left;
void *m;
};
/* Code generator state */
struct _compiler_state {
jmp_buf top_ctx;
pcap_t *bpf_pcap;
int error_set;
struct icode ic;
int snaplen;
int linktype;
int prevlinktype;
int outermostlinktype;
bpf_u_int32 netmask;
int no_optimize;
/* Hack for handling VLAN and MPLS stacks. */
u_int label_stack_depth;
u_int vlan_stack_depth;
/* XXX */
u_int pcap_fddipad;
/*
* As errors are handled by a longjmp, anything allocated must
* be freed in the longjmp handler, so it must be reachable
* from that handler.
*
* One thing that's allocated is the result of pcap_nametoaddrinfo();
* it must be freed with freeaddrinfo(). This variable points to
* any addrinfo structure that would need to be freed.
*/
struct addrinfo *ai;
/*
* Another thing that's allocated is the result of pcap_ether_aton();
* it must be freed with free(). This variable points to any
* address that would need to be freed.
*/
u_char *e;
/*
* Various code constructs need to know the layout of the packet.
* These values give the necessary offsets from the beginning
* of the packet data.
*/
/*
* Absolute offset of the beginning of the link-layer header.
*/
bpf_abs_offset off_linkhdr;
/*
* If we're checking a link-layer header for a packet encapsulated
* in another protocol layer, this is the equivalent information
* for the previous layers' link-layer header from the beginning
* of the raw packet data.
*/
bpf_abs_offset off_prevlinkhdr;
/*
* This is the equivalent information for the outermost layers'
* link-layer header.
*/
bpf_abs_offset off_outermostlinkhdr;
/*
* Absolute offset of the beginning of the link-layer payload.
*/
bpf_abs_offset off_linkpl;
/*
* "off_linktype" is the offset to information in the link-layer
* header giving the packet type. This is an absolute offset
* from the beginning of the packet.
*
* For Ethernet, it's the offset of the Ethernet type field; this
* means that it must have a value that skips VLAN tags.
*
* For link-layer types that always use 802.2 headers, it's the
* offset of the LLC header; this means that it must have a value
* that skips VLAN tags.
*
* For PPP, it's the offset of the PPP type field.
*
* For Cisco HDLC, it's the offset of the CHDLC type field.
*
* For BSD loopback, it's the offset of the AF_ value.
*
* For Linux cooked sockets, it's the offset of the type field.
*
* off_linktype.constant_part is set to OFFSET_NOT_SET for no
* encapsulation, in which case, IP is assumed.
*/
bpf_abs_offset off_linktype;
/*
* TRUE if the link layer includes an ATM pseudo-header.
*/
int is_atm;
/*
* TRUE if "geneve" appeared in the filter; it causes us to
* generate code that checks for a Geneve header and assume
* that later filters apply to the encapsulated payload.
*/
int is_geneve;
/*
* TRUE if we need variable length part of VLAN offset
*/
int is_vlan_vloffset;
/*
* These are offsets for the ATM pseudo-header.
*/
u_int off_vpi;
u_int off_vci;
u_int off_proto;
/*
* These are offsets for the MTP2 fields.
*/
u_int off_li;
u_int off_li_hsl;
/*
* These are offsets for the MTP3 fields.
*/
u_int off_sio;
u_int off_opc;
u_int off_dpc;
u_int off_sls;
/*
* This is the offset of the first byte after the ATM pseudo_header,
* or -1 if there is no ATM pseudo-header.
*/
u_int off_payload;
/*
* These are offsets to the beginning of the network-layer header.
* They are relative to the beginning of the link-layer payload
* (i.e., they don't include off_linkhdr.constant_part or
* off_linkpl.constant_part).
*
* If the link layer never uses 802.2 LLC:
*
* "off_nl" and "off_nl_nosnap" are the same.
*
* If the link layer always uses 802.2 LLC:
*
* "off_nl" is the offset if there's a SNAP header following
* the 802.2 header;
*
* "off_nl_nosnap" is the offset if there's no SNAP header.
*
* If the link layer is Ethernet:
*
* "off_nl" is the offset if the packet is an Ethernet II packet
* (we assume no 802.3+802.2+SNAP);
*
* "off_nl_nosnap" is the offset if the packet is an 802.3 packet
* with an 802.2 header following it.
*/
u_int off_nl;
u_int off_nl_nosnap;
/*
* Here we handle simple allocation of the scratch registers.
* If too many registers are alloc'd, the allocator punts.
*/
int regused[BPF_MEMWORDS];
int curreg;
/*
* Memory chunks.
*/
struct chunk chunks[NCHUNKS];
int cur_chunk;
};
/*
* For use by routines outside this file.
*/
/* VARARGS */
void
bpf_set_error(compiler_state_t *cstate, const char *fmt, ...)
{
va_list ap;
/*
* If we've already set an error, don't override it.
* The lexical analyzer reports some errors by setting
* the error and then returning a LEX_ERROR token, which
* is not recognized by any grammar rule, and thus forces
* the parse to stop. We don't want the error reported
* by the lexical analyzer to be overwritten by the syntax
* error.
*/
if (!cstate->error_set) {
va_start(ap, fmt);
(void)vsnprintf(cstate->bpf_pcap->errbuf, PCAP_ERRBUF_SIZE,
fmt, ap);
va_end(ap);
cstate->error_set = 1;
}
}
/*
* For use *ONLY* in routines in this file.
*/
static void PCAP_NORETURN bpf_error(compiler_state_t *, const char *, ...)
PCAP_PRINTFLIKE(2, 3);
/* VARARGS */
static void PCAP_NORETURN
bpf_error(compiler_state_t *cstate, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
(void)vsnprintf(cstate->bpf_pcap->errbuf, PCAP_ERRBUF_SIZE,
fmt, ap);
va_end(ap);
longjmp(cstate->top_ctx, 1);
/*NOTREACHED*/
#ifdef _AIX
PCAP_UNREACHABLE
#endif /* _AIX */
}
static int init_linktype(compiler_state_t *, pcap_t *);
static void init_regs(compiler_state_t *);
static int alloc_reg(compiler_state_t *);
static void free_reg(compiler_state_t *, int);
static void initchunks(compiler_state_t *cstate);
static void *newchunk_nolongjmp(compiler_state_t *cstate, size_t);
static void *newchunk(compiler_state_t *cstate, size_t);
static void freechunks(compiler_state_t *cstate);
static inline struct block *new_block(compiler_state_t *cstate, int);
static inline struct slist *new_stmt(compiler_state_t *cstate, int);
static struct block *gen_retblk(compiler_state_t *cstate, int);
static inline void syntax(compiler_state_t *cstate);
static void backpatch(struct block *, struct block *);
static void merge(struct block *, struct block *);
static struct block *gen_cmp(compiler_state_t *, enum e_offrel, u_int,
u_int, bpf_u_int32);
static struct block *gen_cmp_gt(compiler_state_t *, enum e_offrel, u_int,
u_int, bpf_u_int32);
static struct block *gen_cmp_ge(compiler_state_t *, enum e_offrel, u_int,
u_int, bpf_u_int32);
static struct block *gen_cmp_lt(compiler_state_t *, enum e_offrel, u_int,
u_int, bpf_u_int32);
static struct block *gen_cmp_le(compiler_state_t *, enum e_offrel, u_int,
u_int, bpf_u_int32);
static struct block *gen_mcmp(compiler_state_t *, enum e_offrel, u_int,
u_int, bpf_u_int32, bpf_u_int32);
static struct block *gen_bcmp(compiler_state_t *, enum e_offrel, u_int,
u_int, const u_char *);
static struct block *gen_ncmp(compiler_state_t *, enum e_offrel, u_int,
u_int, bpf_u_int32, int, int, bpf_u_int32);
static struct slist *gen_load_absoffsetrel(compiler_state_t *, bpf_abs_offset *,
u_int, u_int);
static struct slist *gen_load_a(compiler_state_t *, enum e_offrel, u_int,
u_int);
static struct slist *gen_loadx_iphdrlen(compiler_state_t *);
static struct block *gen_uncond(compiler_state_t *, int);
static inline struct block *gen_true(compiler_state_t *);
static inline struct block *gen_false(compiler_state_t *);
static struct block *gen_ether_linktype(compiler_state_t *, bpf_u_int32);
static struct block *gen_ipnet_linktype(compiler_state_t *, bpf_u_int32);
static struct block *gen_linux_sll_linktype(compiler_state_t *, bpf_u_int32);
static struct slist *gen_load_prism_llprefixlen(compiler_state_t *);
static struct slist *gen_load_avs_llprefixlen(compiler_state_t *);
static struct slist *gen_load_radiotap_llprefixlen(compiler_state_t *);
static struct slist *gen_load_ppi_llprefixlen(compiler_state_t *);
static void insert_compute_vloffsets(compiler_state_t *, struct block *);
static struct slist *gen_abs_offset_varpart(compiler_state_t *,
bpf_abs_offset *);
static bpf_u_int32 ethertype_to_ppptype(bpf_u_int32);
static struct block *gen_linktype(compiler_state_t *, bpf_u_int32);
static struct block *gen_snap(compiler_state_t *, bpf_u_int32, bpf_u_int32);
static struct block *gen_llc_linktype(compiler_state_t *, bpf_u_int32);
static struct block *gen_hostop(compiler_state_t *, bpf_u_int32, bpf_u_int32,
int, bpf_u_int32, u_int, u_int);
#ifdef INET6
static struct block *gen_hostop6(compiler_state_t *, struct in6_addr *,
struct in6_addr *, int, bpf_u_int32, u_int, u_int);
#endif
static struct block *gen_ahostop(compiler_state_t *, const u_char *, int);
static struct block *gen_ehostop(compiler_state_t *, const u_char *, int);
static struct block *gen_fhostop(compiler_state_t *, const u_char *, int);
static struct block *gen_thostop(compiler_state_t *, const u_char *, int);
static struct block *gen_wlanhostop(compiler_state_t *, const u_char *, int);
static struct block *gen_ipfchostop(compiler_state_t *, const u_char *, int);
static struct block *gen_dnhostop(compiler_state_t *, bpf_u_int32, int);
static struct block *gen_mpls_linktype(compiler_state_t *, bpf_u_int32);
static struct block *gen_host(compiler_state_t *, bpf_u_int32, bpf_u_int32,
int, int, int);
#ifdef INET6
static struct block *gen_host6(compiler_state_t *, struct in6_addr *,
struct in6_addr *, int, int, int);
#endif
#ifndef INET6
static struct block *gen_gateway(compiler_state_t *, const u_char *,
struct addrinfo *, int, int);
#endif
static struct block *gen_ipfrag(compiler_state_t *);
static struct block *gen_portatom(compiler_state_t *, int, bpf_u_int32);
static struct block *gen_portrangeatom(compiler_state_t *, u_int, bpf_u_int32,
bpf_u_int32);
static struct block *gen_portatom6(compiler_state_t *, int, bpf_u_int32);
static struct block *gen_portrangeatom6(compiler_state_t *, u_int, bpf_u_int32,
bpf_u_int32);
static struct block *gen_portop(compiler_state_t *, u_int, u_int, int);
static struct block *gen_port(compiler_state_t *, u_int, int, int);
static struct block *gen_portrangeop(compiler_state_t *, u_int, u_int,
bpf_u_int32, int);
static struct block *gen_portrange(compiler_state_t *, u_int, u_int, int, int);
struct block *gen_portop6(compiler_state_t *, u_int, u_int, int);
static struct block *gen_port6(compiler_state_t *, u_int, int, int);
static struct block *gen_portrangeop6(compiler_state_t *, u_int, u_int,
bpf_u_int32, int);
static struct block *gen_portrange6(compiler_state_t *, u_int, u_int, int, int);
static int lookup_proto(compiler_state_t *, const char *, int);
static struct block *gen_protochain(compiler_state_t *, bpf_u_int32, int);
static struct block *gen_proto(compiler_state_t *, bpf_u_int32, int, int);
static struct slist *xfer_to_x(compiler_state_t *, struct arth *);
static struct slist *xfer_to_a(compiler_state_t *, struct arth *);
static struct block *gen_mac_multicast(compiler_state_t *, int);
static struct block *gen_len(compiler_state_t *, int, int);
static struct block *gen_check_802_11_data_frame(compiler_state_t *);
static struct block *gen_geneve_ll_check(compiler_state_t *cstate);
static struct block *gen_ppi_dlt_check(compiler_state_t *);
static struct block *gen_atmfield_code_internal(compiler_state_t *, int,
bpf_u_int32, int, int);
static struct block *gen_atmtype_llc(compiler_state_t *);
static struct block *gen_msg_abbrev(compiler_state_t *, int type);
static void
initchunks(compiler_state_t *cstate)
{
int i;
for (i = 0; i < NCHUNKS; i++) {
cstate->chunks[i].n_left = 0;
cstate->chunks[i].m = NULL;
}
cstate->cur_chunk = 0;
}
static void *
newchunk_nolongjmp(compiler_state_t *cstate, size_t n)
{
struct chunk *cp;
int k;
size_t size;
#ifndef __NetBSD__
/* XXX Round up to nearest long. */
n = (n + sizeof(long) - 1) & ~(sizeof(long) - 1);
#else
/* XXX Round up to structure boundary. */
n = ALIGN(n);
#endif
cp = &cstate->chunks[cstate->cur_chunk];
if (n > cp->n_left) {
++cp;
k = ++cstate->cur_chunk;
if (k >= NCHUNKS) {
bpf_set_error(cstate, "out of memory");
return (NULL);
}
size = CHUNK0SIZE << k;
cp->m = (void *)malloc(size);
if (cp->m == NULL) {
bpf_set_error(cstate, "out of memory");
return (NULL);
}
memset((char *)cp->m, 0, size);
cp->n_left = size;
if (n > size) {
bpf_set_error(cstate, "out of memory");
return (NULL);
}
}
cp->n_left -= n;
return (void *)((char *)cp->m + cp->n_left);
}
static void *
newchunk(compiler_state_t *cstate, size_t n)
{
void *p;
p = newchunk_nolongjmp(cstate, n);
if (p == NULL) {
longjmp(cstate->top_ctx, 1);
/*NOTREACHED*/
}
return (p);
}
static void
freechunks(compiler_state_t *cstate)
{
int i;
for (i = 0; i < NCHUNKS; ++i)
if (cstate->chunks[i].m != NULL)
free(cstate->chunks[i].m);
}
/*
* A strdup whose allocations are freed after code generation is over.
* This is used by the lexical analyzer, so it can't longjmp; it just
* returns NULL on an allocation error, and the callers must check
* for it.
*/
char *
sdup(compiler_state_t *cstate, const char *s)
{
size_t n = strlen(s) + 1;
char *cp = newchunk_nolongjmp(cstate, n);
if (cp == NULL)
return (NULL);
pcap_strlcpy(cp, s, n);
return (cp);
}
static inline struct block *
new_block(compiler_state_t *cstate, int code)
{
struct block *p;
p = (struct block *)newchunk(cstate, sizeof(*p));
p->s.code = code;
p->head = p;
return p;
}
static inline struct slist *
new_stmt(compiler_state_t *cstate, int code)
{
struct slist *p;
p = (struct slist *)newchunk(cstate, sizeof(*p));
p->s.code = code;
return p;
}
static struct block *
gen_retblk(compiler_state_t *cstate, int v)
{
struct block *b = new_block(cstate, BPF_RET|BPF_K);
b->s.k = v;
return b;
}
static inline PCAP_NORETURN_DEF void
syntax(compiler_state_t *cstate)
{
bpf_error(cstate, "syntax error in filter expression");
}
int
pcap_compile(pcap_t *p, struct bpf_program *program,
const char *buf, int optimize, bpf_u_int32 mask)
{
#ifdef _WIN32
static int done = 0;
#endif
compiler_state_t cstate;
const char * volatile xbuf = buf;
yyscan_t scanner = NULL;
volatile YY_BUFFER_STATE in_buffer = NULL;
u_int len;
int rc;
/*
* If this pcap_t hasn't been activated, it doesn't have a
* link-layer type, so we can't use it.
*/
if (!p->activated) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"not-yet-activated pcap_t passed to pcap_compile");
return (-1);
}
#ifdef _WIN32
if (!done)
pcap_wsockinit();
done = 1;
#endif
#ifdef ENABLE_REMOTE
/*
* If the device on which we're capturing need to be notified
* that a new filter is being compiled, do so.
*
* This allows them to save a copy of it, in case, for example,
* they're implementing a form of remote packet capture, and
* want the remote machine to filter out the packets in which
* it's sending the packets it's captured.
*
* XXX - the fact that we happen to be compiling a filter
* doesn't necessarily mean we'll be installing it as the
* filter for this pcap_t; we might be running it from userland
* on captured packets to do packet classification. We really
* need a better way of handling this, but this is all that
* the WinPcap remote capture code did.
*/
if (p->save_current_filter_op != NULL)
(p->save_current_filter_op)(p, buf);
#endif
initchunks(&cstate);
cstate.no_optimize = 0;
#ifdef INET6
cstate.ai = NULL;
#endif
cstate.e = NULL;
cstate.ic.root = NULL;
cstate.ic.cur_mark = 0;
cstate.bpf_pcap = p;
cstate.error_set = 0;
init_regs(&cstate);
cstate.netmask = mask;
cstate.snaplen = pcap_snapshot(p);
if (cstate.snaplen == 0) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"snaplen of 0 rejects all packets");
rc = -1;
goto quit;
}
if (pcap_lex_init(&scanner) != 0)
pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "can't initialize scanner");
in_buffer = pcap__scan_string(xbuf ? xbuf : "", scanner);
/*
* Associate the compiler state with the lexical analyzer
* state.
*/
pcap_set_extra(&cstate, scanner);
if (init_linktype(&cstate, p) == -1) {
rc = -1;
goto quit;
}
if (pcap_parse(scanner, &cstate) != 0) {
#ifdef INET6
if (cstate.ai != NULL)
freeaddrinfo(cstate.ai);
#endif
if (cstate.e != NULL)
free(cstate.e);
rc = -1;
goto quit;
}
if (cstate.ic.root == NULL) {
/*
* Catch errors reported by gen_retblk().
*/
if (setjmp(cstate.top_ctx)) {
rc = -1;
goto quit;
}
cstate.ic.root = gen_retblk(&cstate, cstate.snaplen);
}
if (optimize && !cstate.no_optimize) {
if (bpf_optimize(&cstate.ic, p->errbuf) == -1) {
/* Failure */
rc = -1;
goto quit;
}
if (cstate.ic.root == NULL ||
(cstate.ic.root->s.code == (BPF_RET|BPF_K) && cstate.ic.root->s.k == 0)) {
(void)snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"expression rejects all packets");
rc = -1;
goto quit;
}
}
program->bf_insns = icode_to_fcode(&cstate.ic,
cstate.ic.root, &len, p->errbuf);
if (program->bf_insns == NULL) {
/* Failure */
rc = -1;
goto quit;
}
program->bf_len = len;
rc = 0; /* We're all okay */
quit:
/*
* Clean up everything for the lexical analyzer.
*/
if (in_buffer != NULL)
pcap__delete_buffer(in_buffer, scanner);
if (scanner != NULL)
pcap_lex_destroy(scanner);
/*
* Clean up our own allocated memory.
*/
freechunks(&cstate);
return (rc);
}
/*
* entry point for using the compiler with no pcap open
* pass in all the stuff that is needed explicitly instead.
*/
int
pcap_compile_nopcap(int snaplen_arg, int linktype_arg,
struct bpf_program *program,
const char *buf, int optimize, bpf_u_int32 mask)
{
pcap_t *p;
int ret;
p = pcap_open_dead(linktype_arg, snaplen_arg);
if (p == NULL)
return (-1);
ret = pcap_compile(p, program, buf, optimize, mask);
pcap_close(p);
return (ret);
}
/*
* Clean up a "struct bpf_program" by freeing all the memory allocated
* in it.
*/
void
pcap_freecode(struct bpf_program *program)
{
program->bf_len = 0;
if (program->bf_insns != NULL) {
free((char *)program->bf_insns);
program->bf_insns = NULL;
}
}
/*
* Backpatch the blocks in 'list' to 'target'. The 'sense' field indicates
* which of the jt and jf fields has been resolved and which is a pointer
* back to another unresolved block (or nil). At least one of the fields
* in each block is already resolved.
*/
static void
backpatch(struct block *list, struct block *target)
{
struct block *next;
while (list) {
if (!list->sense) {
next = JT(list);
JT(list) = target;
} else {
next = JF(list);
JF(list) = target;
}
list = next;
}
}
/*
* Merge the lists in b0 and b1, using the 'sense' field to indicate
* which of jt and jf is the link.
*/
static void
merge(struct block *b0, struct block *b1)
{
register struct block **p = &b0;
/* Find end of list. */
while (*p)
p = !((*p)->sense) ? &JT(*p) : &JF(*p);
/* Concatenate the lists. */
*p = b1;
}
int
finish_parse(compiler_state_t *cstate, struct block *p)
{
struct block *ppi_dlt_check;
/*
* Catch errors reported by us and routines below us, and return -1
* on an error.
*/
if (setjmp(cstate->top_ctx))
return (-1);
/*
* Insert before the statements of the first (root) block any
* statements needed to load the lengths of any variable-length
* headers into registers.
*
* XXX - a fancier strategy would be to insert those before the
* statements of all blocks that use those lengths and that
* have no predecessors that use them, so that we only compute
* the lengths if we need them. There might be even better
* approaches than that.
*
* However, those strategies would be more complicated, and
* as we don't generate code to compute a length if the
* program has no tests that use the length, and as most
* tests will probably use those lengths, we would just
* postpone computing the lengths so that it's not done
* for tests that fail early, and it's not clear that's
* worth the effort.
*/
insert_compute_vloffsets(cstate, p->head);
/*
* For DLT_PPI captures, generate a check of the per-packet
* DLT value to make sure it's DLT_IEEE802_11.
*
* XXX - TurboCap cards use DLT_PPI for Ethernet.
* Can we just define some DLT_ETHERNET_WITH_PHDR pseudo-header
* with appropriate Ethernet information and use that rather
* than using something such as DLT_PPI where you don't know
* the link-layer header type until runtime, which, in the
* general case, would force us to generate both Ethernet *and*
* 802.11 code (*and* anything else for which PPI is used)
* and choose between them early in the BPF program?
*/
ppi_dlt_check = gen_ppi_dlt_check(cstate);
if (ppi_dlt_check != NULL)
gen_and(ppi_dlt_check, p);