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[libpcap] / gencode.c
1 /*#define CHASE_CHAIN*/
2 /*
3 * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998
4 * The Regents of the University of California. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that: (1) source code distributions
8 * retain the above copyright notice and this paragraph in its entirety, (2)
9 * distributions including binary code include the above copyright notice and
10 * this paragraph in its entirety in the documentation or other materials
11 * provided with the distribution, and (3) all advertising materials mentioning
12 * features or use of this software display the following acknowledgement:
13 * ``This product includes software developed by the University of California,
14 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
15 * the University nor the names of its contributors may be used to endorse
16 * or promote products derived from this software without specific prior
17 * written permission.
18 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
19 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
20 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
21 */
22 #ifndef lint
23 static const char rcsid[] _U_ =
24 "@(#) $Header: /tcpdump/master/libpcap/gencode.c,v 1.260 2005-09-05 09:06:59 guy Exp $ (LBL)";
25 #endif
26
27 #ifdef HAVE_CONFIG_H
28 #include "config.h"
29 #endif
30
31 #ifdef WIN32
32 #include <pcap-stdinc.h>
33 #else /* WIN32 */
34 #include <sys/types.h>
35 #include <sys/socket.h>
36 #endif /* WIN32 */
37
38 /*
39 * XXX - why was this included even on UNIX?
40 */
41 #ifdef __MINGW32__
42 #include "IP6_misc.h"
43 #endif
44
45 #ifndef WIN32
46
47 #ifdef __NetBSD__
48 #include <sys/param.h>
49 #endif
50
51 #include <netinet/in.h>
52
53 #endif /* WIN32 */
54
55 #include <stdlib.h>
56 #include <string.h>
57 #include <memory.h>
58 #include <setjmp.h>
59 #include <stdarg.h>
60
61 #ifdef MSDOS
62 #include "pcap-dos.h"
63 #endif
64
65 #include "pcap-int.h"
66
67 #include "ethertype.h"
68 #include "nlpid.h"
69 #include "llc.h"
70 #include "gencode.h"
71 #include "atmuni31.h"
72 #include "sunatmpos.h"
73 #include "ppp.h"
74 #include "sll.h"
75 #include "arcnet.h"
76 #include "pf.h"
77 #ifndef offsetof
78 #define offsetof(s, e) ((size_t)&((s *)0)->e)
79 #endif
80 #ifdef INET6
81 #ifndef WIN32
82 #include <netdb.h> /* for "struct addrinfo" */
83 #endif /* WIN32 */
84 #endif /*INET6*/
85 #include <pcap-namedb.h>
86
87 #define ETHERMTU 1500
88
89 #ifndef IPPROTO_SCTP
90 #define IPPROTO_SCTP 132
91 #endif
92
93 #ifdef HAVE_OS_PROTO_H
94 #include "os-proto.h"
95 #endif
96
97 #define JMP(c) ((c)|BPF_JMP|BPF_K)
98
99 /* Locals */
100 static jmp_buf top_ctx;
101 static pcap_t *bpf_pcap;
102
103 /* Hack for updating VLAN, MPLS, and PPPoE offsets. */
104 static u_int orig_linktype = -1U, orig_nl = -1U, label_stack_depth = -1U;
105
106 /* XXX */
107 #ifdef PCAP_FDDIPAD
108 static int pcap_fddipad;
109 #endif
110
111 /* VARARGS */
112 void
113 bpf_error(const char *fmt, ...)
114 {
115 va_list ap;
116
117 va_start(ap, fmt);
118 if (bpf_pcap != NULL)
119 (void)vsnprintf(pcap_geterr(bpf_pcap), PCAP_ERRBUF_SIZE,
120 fmt, ap);
121 va_end(ap);
122 longjmp(top_ctx, 1);
123 /* NOTREACHED */
124 }
125
126 static void init_linktype(pcap_t *);
127
128 static int alloc_reg(void);
129 static void free_reg(int);
130
131 static struct block *root;
132
133 /*
134 * Value passed to gen_load_a() to indicate what the offset argument
135 * is relative to.
136 */
137 enum e_offrel {
138 OR_PACKET, /* relative to the beginning of the packet */
139 OR_LINK, /* relative to the link-layer header */
140 OR_NET, /* relative to the network-layer header */
141 OR_NET_NOSNAP, /* relative to the network-layer header, with no SNAP header at the link layer */
142 OR_TRAN_IPV4, /* relative to the transport-layer header, with IPv4 network layer */
143 OR_TRAN_IPV6 /* relative to the transport-layer header, with IPv6 network layer */
144 };
145
146 /*
147 * We divy out chunks of memory rather than call malloc each time so
148 * we don't have to worry about leaking memory. It's probably
149 * not a big deal if all this memory was wasted but if this ever
150 * goes into a library that would probably not be a good idea.
151 *
152 * XXX - this *is* in a library....
153 */
154 #define NCHUNKS 16
155 #define CHUNK0SIZE 1024
156 struct chunk {
157 u_int n_left;
158 void *m;
159 };
160
161 static struct chunk chunks[NCHUNKS];
162 static int cur_chunk;
163
164 static void *newchunk(u_int);
165 static void freechunks(void);
166 static inline struct block *new_block(int);
167 static inline struct slist *new_stmt(int);
168 static struct block *gen_retblk(int);
169 static inline void syntax(void);
170
171 static void backpatch(struct block *, struct block *);
172 static void merge(struct block *, struct block *);
173 static struct block *gen_cmp(enum e_offrel, u_int, u_int, bpf_int32);
174 static struct block *gen_cmp_gt(enum e_offrel, u_int, u_int, bpf_int32);
175 static struct block *gen_cmp_ge(enum e_offrel, u_int, u_int, bpf_int32);
176 static struct block *gen_cmp_lt(enum e_offrel, u_int, u_int, bpf_int32);
177 static struct block *gen_cmp_le(enum e_offrel, u_int, u_int, bpf_int32);
178 static struct block *gen_mcmp(enum e_offrel, u_int, u_int, bpf_int32,
179 bpf_u_int32);
180 static struct block *gen_bcmp(enum e_offrel, u_int, u_int, const u_char *);
181 static struct block *gen_ncmp(enum e_offrel, bpf_u_int32, bpf_u_int32,
182 bpf_u_int32, bpf_u_int32, int, bpf_int32);
183 static struct slist *gen_load_llrel(u_int, u_int);
184 static struct slist *gen_load_a(enum e_offrel, u_int, u_int);
185 static struct slist *gen_loadx_iphdrlen(void);
186 static struct block *gen_uncond(int);
187 static inline struct block *gen_true(void);
188 static inline struct block *gen_false(void);
189 static struct block *gen_ether_linktype(int);
190 static struct block *gen_linux_sll_linktype(int);
191 static void insert_radiotap_load_llprefixlen(struct block *);
192 static void insert_load_llprefixlen(struct block *);
193 static struct slist *gen_llprefixlen(void);
194 static struct block *gen_linktype(int);
195 static struct block *gen_snap(bpf_u_int32, bpf_u_int32, u_int);
196 static struct block *gen_llc_linktype(int);
197 static struct block *gen_hostop(bpf_u_int32, bpf_u_int32, int, int, u_int, u_int);
198 #ifdef INET6
199 static struct block *gen_hostop6(struct in6_addr *, struct in6_addr *, int, int, u_int, u_int);
200 #endif
201 static struct block *gen_ahostop(const u_char *, int);
202 static struct block *gen_ehostop(const u_char *, int);
203 static struct block *gen_fhostop(const u_char *, int);
204 static struct block *gen_thostop(const u_char *, int);
205 static struct block *gen_wlanhostop(const u_char *, int);
206 static struct block *gen_ipfchostop(const u_char *, int);
207 static struct block *gen_dnhostop(bpf_u_int32, int);
208 static struct block *gen_mpls_linktype(int);
209 static struct block *gen_host(bpf_u_int32, bpf_u_int32, int, int);
210 #ifdef INET6
211 static struct block *gen_host6(struct in6_addr *, struct in6_addr *, int, int);
212 #endif
213 #ifndef INET6
214 static struct block *gen_gateway(const u_char *, bpf_u_int32 **, int, int);
215 #endif
216 static struct block *gen_ipfrag(void);
217 static struct block *gen_portatom(int, bpf_int32);
218 static struct block *gen_portrangeatom(int, bpf_int32, bpf_int32);
219 #ifdef INET6
220 static struct block *gen_portatom6(int, bpf_int32);
221 static struct block *gen_portrangeatom6(int, bpf_int32, bpf_int32);
222 #endif
223 struct block *gen_portop(int, int, int);
224 static struct block *gen_port(int, int, int);
225 struct block *gen_portrangeop(int, int, int, int);
226 static struct block *gen_portrange(int, int, int, int);
227 #ifdef INET6
228 struct block *gen_portop6(int, int, int);
229 static struct block *gen_port6(int, int, int);
230 struct block *gen_portrangeop6(int, int, int, int);
231 static struct block *gen_portrange6(int, int, int, int);
232 #endif
233 static int lookup_proto(const char *, int);
234 static struct block *gen_protochain(int, int, int);
235 static struct block *gen_proto(int, int, int);
236 static struct slist *xfer_to_x(struct arth *);
237 static struct slist *xfer_to_a(struct arth *);
238 static struct block *gen_mac_multicast(int);
239 static struct block *gen_len(int, int);
240
241 static struct block *gen_msg_abbrev(int type);
242
243 static void *
244 newchunk(n)
245 u_int n;
246 {
247 struct chunk *cp;
248 int k;
249 size_t size;
250
251 #ifndef __NetBSD__
252 /* XXX Round up to nearest long. */
253 n = (n + sizeof(long) - 1) & ~(sizeof(long) - 1);
254 #else
255 /* XXX Round up to structure boundary. */
256 n = ALIGN(n);
257 #endif
258
259 cp = &chunks[cur_chunk];
260 if (n > cp->n_left) {
261 ++cp, k = ++cur_chunk;
262 if (k >= NCHUNKS)
263 bpf_error("out of memory");
264 size = CHUNK0SIZE << k;
265 cp->m = (void *)malloc(size);
266 if (cp->m == NULL)
267 bpf_error("out of memory");
268 memset((char *)cp->m, 0, size);
269 cp->n_left = size;
270 if (n > size)
271 bpf_error("out of memory");
272 }
273 cp->n_left -= n;
274 return (void *)((char *)cp->m + cp->n_left);
275 }
276
277 static void
278 freechunks()
279 {
280 int i;
281
282 cur_chunk = 0;
283 for (i = 0; i < NCHUNKS; ++i)
284 if (chunks[i].m != NULL) {
285 free(chunks[i].m);
286 chunks[i].m = NULL;
287 }
288 }
289
290 /*
291 * A strdup whose allocations are freed after code generation is over.
292 */
293 char *
294 sdup(s)
295 register const char *s;
296 {
297 int n = strlen(s) + 1;
298 char *cp = newchunk(n);
299
300 strlcpy(cp, s, n);
301 return (cp);
302 }
303
304 static inline struct block *
305 new_block(code)
306 int code;
307 {
308 struct block *p;
309
310 p = (struct block *)newchunk(sizeof(*p));
311 p->s.code = code;
312 p->head = p;
313
314 return p;
315 }
316
317 static inline struct slist *
318 new_stmt(code)
319 int code;
320 {
321 struct slist *p;
322
323 p = (struct slist *)newchunk(sizeof(*p));
324 p->s.code = code;
325
326 return p;
327 }
328
329 static struct block *
330 gen_retblk(v)
331 int v;
332 {
333 struct block *b = new_block(BPF_RET|BPF_K);
334
335 b->s.k = v;
336 return b;
337 }
338
339 static inline void
340 syntax()
341 {
342 bpf_error("syntax error in filter expression");
343 }
344
345 static bpf_u_int32 netmask;
346 static int snaplen;
347 int no_optimize;
348
349 int
350 pcap_compile(pcap_t *p, struct bpf_program *program,
351 char *buf, int optimize, bpf_u_int32 mask)
352 {
353 extern int n_errors;
354 int len;
355
356 no_optimize = 0;
357 n_errors = 0;
358 root = NULL;
359 bpf_pcap = p;
360 if (setjmp(top_ctx)) {
361 lex_cleanup();
362 freechunks();
363 return (-1);
364 }
365
366 netmask = mask;
367
368 snaplen = pcap_snapshot(p);
369 if (snaplen == 0) {
370 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
371 "snaplen of 0 rejects all packets");
372 return -1;
373 }
374
375 lex_init(buf ? buf : "");
376 init_linktype(p);
377 (void)pcap_parse();
378
379 if (n_errors)
380 syntax();
381
382 if (root == NULL)
383 root = gen_retblk(snaplen);
384
385 if (optimize && !no_optimize) {
386 bpf_optimize(&root);
387 if (root == NULL ||
388 (root->s.code == (BPF_RET|BPF_K) && root->s.k == 0))
389 bpf_error("expression rejects all packets");
390 }
391 program->bf_insns = icode_to_fcode(root, &len);
392 program->bf_len = len;
393
394 lex_cleanup();
395 freechunks();
396 return (0);
397 }
398
399 /*
400 * entry point for using the compiler with no pcap open
401 * pass in all the stuff that is needed explicitly instead.
402 */
403 int
404 pcap_compile_nopcap(int snaplen_arg, int linktype_arg,
405 struct bpf_program *program,
406 char *buf, int optimize, bpf_u_int32 mask)
407 {
408 pcap_t *p;
409 int ret;
410
411 p = pcap_open_dead(linktype_arg, snaplen_arg);
412 if (p == NULL)
413 return (-1);
414 ret = pcap_compile(p, program, buf, optimize, mask);
415 pcap_close(p);
416 return (ret);
417 }
418
419 /*
420 * Clean up a "struct bpf_program" by freeing all the memory allocated
421 * in it.
422 */
423 void
424 pcap_freecode(struct bpf_program *program)
425 {
426 program->bf_len = 0;
427 if (program->bf_insns != NULL) {
428 free((char *)program->bf_insns);
429 program->bf_insns = NULL;
430 }
431 }
432
433 /*
434 * Backpatch the blocks in 'list' to 'target'. The 'sense' field indicates
435 * which of the jt and jf fields has been resolved and which is a pointer
436 * back to another unresolved block (or nil). At least one of the fields
437 * in each block is already resolved.
438 */
439 static void
440 backpatch(list, target)
441 struct block *list, *target;
442 {
443 struct block *next;
444
445 while (list) {
446 if (!list->sense) {
447 next = JT(list);
448 JT(list) = target;
449 } else {
450 next = JF(list);
451 JF(list) = target;
452 }
453 list = next;
454 }
455 }
456
457 /*
458 * Merge the lists in b0 and b1, using the 'sense' field to indicate
459 * which of jt and jf is the link.
460 */
461 static void
462 merge(b0, b1)
463 struct block *b0, *b1;
464 {
465 register struct block **p = &b0;
466
467 /* Find end of list. */
468 while (*p)
469 p = !((*p)->sense) ? &JT(*p) : &JF(*p);
470
471 /* Concatenate the lists. */
472 *p = b1;
473 }
474
475 void
476 finish_parse(p)
477 struct block *p;
478 {
479 backpatch(p, gen_retblk(snaplen));
480 p->sense = !p->sense;
481 backpatch(p, gen_retblk(0));
482 root = p->head;
483
484 /*
485 * Insert before the statements of the first (root) block any
486 * statements needed to load the lengths of any variable-length
487 * headers into registers.
488 *
489 * XXX - a fancier strategy would be to insert those before the
490 * statements of all blocks that use those lengths and that
491 * have no predecessors that use them, so that we only compute
492 * the lengths if we need them. There might be even better
493 * approaches than that. However, as we're currently only
494 * handling variable-length radiotap headers, and as all
495 * filtering expressions other than raw link[M:N] tests
496 * require the length of that header, doing more for that
497 * header length isn't really worth the effort.
498 */
499 insert_load_llprefixlen(root);
500 }
501
502 void
503 gen_and(b0, b1)
504 struct block *b0, *b1;
505 {
506 backpatch(b0, b1->head);
507 b0->sense = !b0->sense;
508 b1->sense = !b1->sense;
509 merge(b1, b0);
510 b1->sense = !b1->sense;
511 b1->head = b0->head;
512 }
513
514 void
515 gen_or(b0, b1)
516 struct block *b0, *b1;
517 {
518 b0->sense = !b0->sense;
519 backpatch(b0, b1->head);
520 b0->sense = !b0->sense;
521 merge(b1, b0);
522 b1->head = b0->head;
523 }
524
525 void
526 gen_not(b)
527 struct block *b;
528 {
529 b->sense = !b->sense;
530 }
531
532 static struct block *
533 gen_cmp(offrel, offset, size, v)
534 enum e_offrel offrel;
535 u_int offset, size;
536 bpf_int32 v;
537 {
538 return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JEQ, 0, v);
539 }
540
541 static struct block *
542 gen_cmp_gt(offrel, offset, size, v)
543 enum e_offrel offrel;
544 u_int offset, size;
545 bpf_int32 v;
546 {
547 return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JGT, 0, v);
548 }
549
550 static struct block *
551 gen_cmp_ge(offrel, offset, size, v)
552 enum e_offrel offrel;
553 u_int offset, size;
554 bpf_int32 v;
555 {
556 return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JGE, 0, v);
557 }
558
559 static struct block *
560 gen_cmp_lt(offrel, offset, size, v)
561 enum e_offrel offrel;
562 u_int offset, size;
563 bpf_int32 v;
564 {
565 return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JGE, 1, v);
566 }
567
568 static struct block *
569 gen_cmp_le(offrel, offset, size, v)
570 enum e_offrel offrel;
571 u_int offset, size;
572 bpf_int32 v;
573 {
574 return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JGT, 1, v);
575 }
576
577 static struct block *
578 gen_mcmp(offrel, offset, size, v, mask)
579 enum e_offrel offrel;
580 u_int offset, size;
581 bpf_int32 v;
582 bpf_u_int32 mask;
583 {
584 return gen_ncmp(offrel, offset, size, mask, BPF_JEQ, 0, v);
585 }
586
587 static struct block *
588 gen_bcmp(offrel, offset, size, v)
589 enum e_offrel offrel;
590 register u_int offset, size;
591 register const u_char *v;
592 {
593 register struct block *b, *tmp;
594
595 b = NULL;
596 while (size >= 4) {
597 register const u_char *p = &v[size - 4];
598 bpf_int32 w = ((bpf_int32)p[0] << 24) |
599 ((bpf_int32)p[1] << 16) | ((bpf_int32)p[2] << 8) | p[3];
600
601 tmp = gen_cmp(offrel, offset + size - 4, BPF_W, w);
602 if (b != NULL)
603 gen_and(b, tmp);
604 b = tmp;
605 size -= 4;
606 }
607 while (size >= 2) {
608 register const u_char *p = &v[size - 2];
609 bpf_int32 w = ((bpf_int32)p[0] << 8) | p[1];
610
611 tmp = gen_cmp(offrel, offset + size - 2, BPF_H, w);
612 if (b != NULL)
613 gen_and(b, tmp);
614 b = tmp;
615 size -= 2;
616 }
617 if (size > 0) {
618 tmp = gen_cmp(offrel, offset, BPF_B, (bpf_int32)v[0]);
619 if (b != NULL)
620 gen_and(b, tmp);
621 b = tmp;
622 }
623 return b;
624 }
625
626 /*
627 * AND the field of size "size" at offset "offset" relative to the header
628 * specified by "offrel" with "mask", and compare it with the value "v"
629 * with the test specified by "jtype"; if "reverse" is true, the test
630 * should test the opposite of "jtype".
631 */
632 static struct block *
633 gen_ncmp(offrel, offset, size, mask, jtype, reverse, v)
634 enum e_offrel offrel;
635 bpf_int32 v;
636 bpf_u_int32 offset, size, mask, jtype;
637 int reverse;
638 {
639 struct slist *s, *s2;
640 struct block *b;
641
642 s = gen_load_a(offrel, offset, size);
643
644 if (mask != 0xffffffff) {
645 s2 = new_stmt(BPF_ALU|BPF_AND|BPF_K);
646 s2->s.k = mask;
647 sappend(s, s2);
648 }
649
650 b = new_block(JMP(jtype));
651 b->stmts = s;
652 b->s.k = v;
653 if (reverse && (jtype == BPF_JGT || jtype == BPF_JGE))
654 gen_not(b);
655 return b;
656 }
657
658 /*
659 * Various code constructs need to know the layout of the data link
660 * layer. These variables give the necessary offsets from the beginning
661 * of the packet data.
662 *
663 * If the link layer has variable_length headers, the offsets are offsets
664 * from the end of the link-link-layer header, and "reg_ll_size" is
665 * the register number for a register containing the length of the
666 * link-layer header. Otherwise, "reg_ll_size" is -1.
667 */
668 static int reg_ll_size;
669
670 /*
671 * This is the offset of the beginning of the link-layer header.
672 * It's usually 0, except for 802.11 with a fixed-length radio header.
673 */
674 static u_int off_ll;
675
676 /*
677 * This is the offset of the beginning of the MAC-layer header.
678 * It's usually 0, except for ATM LANE.
679 */
680 static u_int off_mac;
681
682 /*
683 * "off_linktype" is the offset to information in the link-layer header
684 * giving the packet type.
685 *
686 * For Ethernet, it's the offset of the Ethernet type field.
687 *
688 * For link-layer types that always use 802.2 headers, it's the
689 * offset of the LLC header.
690 *
691 * For PPP, it's the offset of the PPP type field.
692 *
693 * For Cisco HDLC, it's the offset of the CHDLC type field.
694 *
695 * For BSD loopback, it's the offset of the AF_ value.
696 *
697 * For Linux cooked sockets, it's the offset of the type field.
698 *
699 * It's set to -1 for no encapsulation, in which case, IP is assumed.
700 */
701 static u_int off_linktype;
702
703 /*
704 * TRUE if the link layer includes an ATM pseudo-header.
705 */
706 static int is_atm = 0;
707
708 /*
709 * TRUE if "lane" appeared in the filter; it causes us to generate
710 * code that assumes LANE rather than LLC-encapsulated traffic in SunATM.
711 */
712 static int is_lane = 0;
713
714 /*
715 * These are offsets for the ATM pseudo-header.
716 */
717 static u_int off_vpi;
718 static u_int off_vci;
719 static u_int off_proto;
720
721 /*
722 * These are offsets for the MTP3 fields.
723 */
724 static u_int off_sio;
725 static u_int off_opc;
726 static u_int off_dpc;
727 static u_int off_sls;
728
729 /*
730 * This is the offset of the first byte after the ATM pseudo_header,
731 * or -1 if there is no ATM pseudo-header.
732 */
733 static u_int off_payload;
734
735 /*
736 * These are offsets to the beginning of the network-layer header.
737 *
738 * If the link layer never uses 802.2 LLC:
739 *
740 * "off_nl" and "off_nl_nosnap" are the same.
741 *
742 * If the link layer always uses 802.2 LLC:
743 *
744 * "off_nl" is the offset if there's a SNAP header following
745 * the 802.2 header;
746 *
747 * "off_nl_nosnap" is the offset if there's no SNAP header.
748 *
749 * If the link layer is Ethernet:
750 *
751 * "off_nl" is the offset if the packet is an Ethernet II packet
752 * (we assume no 802.3+802.2+SNAP);
753 *
754 * "off_nl_nosnap" is the offset if the packet is an 802.3 packet
755 * with an 802.2 header following it.
756 */
757 static u_int off_nl;
758 static u_int off_nl_nosnap;
759
760 static int linktype;
761
762 static void
763 init_linktype(p)
764 pcap_t *p;
765 {
766 linktype = pcap_datalink(p);
767 #ifdef PCAP_FDDIPAD
768 pcap_fddipad = p->fddipad;
769 #endif
770
771 /*
772 * Assume it's not raw ATM with a pseudo-header, for now.
773 */
774 off_mac = 0;
775 is_atm = 0;
776 is_lane = 0;
777 off_vpi = -1;
778 off_vci = -1;
779 off_proto = -1;
780 off_payload = -1;
781
782 /*
783 * And assume we're not doing SS7.
784 */
785 off_sio = -1;
786 off_opc = -1;
787 off_dpc = -1;
788 off_sls = -1;
789
790 /*
791 * Also assume it's not 802.11 with a fixed-length radio header.
792 */
793 off_ll = 0;
794
795 orig_linktype = -1;
796 orig_nl = -1;
797 label_stack_depth = 0;
798
799 reg_ll_size = -1;
800
801 switch (linktype) {
802
803 case DLT_ARCNET:
804 off_linktype = 2;
805 off_nl = 6; /* XXX in reality, variable! */
806 off_nl_nosnap = 6; /* no 802.2 LLC */
807 return;
808
809 case DLT_ARCNET_LINUX:
810 off_linktype = 4;
811 off_nl = 8; /* XXX in reality, variable! */
812 off_nl_nosnap = 8; /* no 802.2 LLC */
813 return;
814
815 case DLT_EN10MB:
816 off_linktype = 12;
817 off_nl = 14; /* Ethernet II */
818 off_nl_nosnap = 17; /* 802.3+802.2 */
819 return;
820
821 case DLT_SLIP:
822 /*
823 * SLIP doesn't have a link level type. The 16 byte
824 * header is hacked into our SLIP driver.
825 */
826 off_linktype = -1;
827 off_nl = 16;
828 off_nl_nosnap = 16; /* no 802.2 LLC */
829 return;
830
831 case DLT_SLIP_BSDOS:
832 /* XXX this may be the same as the DLT_PPP_BSDOS case */
833 off_linktype = -1;
834 /* XXX end */
835 off_nl = 24;
836 off_nl_nosnap = 24; /* no 802.2 LLC */
837 return;
838
839 case DLT_NULL:
840 case DLT_LOOP:
841 off_linktype = 0;
842 off_nl = 4;
843 off_nl_nosnap = 4; /* no 802.2 LLC */
844 return;
845
846 case DLT_ENC:
847 off_linktype = 0;
848 off_nl = 12;
849 off_nl_nosnap = 12; /* no 802.2 LLC */
850 return;
851
852 case DLT_PPP:
853 case DLT_PPP_PPPD:
854 case DLT_C_HDLC: /* BSD/OS Cisco HDLC */
855 case DLT_PPP_SERIAL: /* NetBSD sync/async serial PPP */
856 off_linktype = 2;
857 off_nl = 4;
858 off_nl_nosnap = 4; /* no 802.2 LLC */
859 return;
860
861 case DLT_PPP_ETHER:
862 /*
863 * This does no include the Ethernet header, and
864 * only covers session state.
865 */
866 off_linktype = 6;
867 off_nl = 8;
868 off_nl_nosnap = 8; /* no 802.2 LLC */
869 return;
870
871 case DLT_PPP_BSDOS:
872 off_linktype = 5;
873 off_nl = 24;
874 off_nl_nosnap = 24; /* no 802.2 LLC */
875 return;
876
877 case DLT_FDDI:
878 /*
879 * FDDI doesn't really have a link-level type field.
880 * We set "off_linktype" to the offset of the LLC header.
881 *
882 * To check for Ethernet types, we assume that SSAP = SNAP
883 * is being used and pick out the encapsulated Ethernet type.
884 * XXX - should we generate code to check for SNAP?
885 */
886 off_linktype = 13;
887 #ifdef PCAP_FDDIPAD
888 off_linktype += pcap_fddipad;
889 #endif
890 off_nl = 21; /* FDDI+802.2+SNAP */
891 off_nl_nosnap = 16; /* FDDI+802.2 */
892 #ifdef PCAP_FDDIPAD
893 off_nl += pcap_fddipad;
894 off_nl_nosnap += pcap_fddipad;
895 #endif
896 return;
897
898 case DLT_IEEE802:
899 /*
900 * Token Ring doesn't really have a link-level type field.
901 * We set "off_linktype" to the offset of the LLC header.
902 *
903 * To check for Ethernet types, we assume that SSAP = SNAP
904 * is being used and pick out the encapsulated Ethernet type.
905 * XXX - should we generate code to check for SNAP?
906 *
907 * XXX - the header is actually variable-length.
908 * Some various Linux patched versions gave 38
909 * as "off_linktype" and 40 as "off_nl"; however,
910 * if a token ring packet has *no* routing
911 * information, i.e. is not source-routed, the correct
912 * values are 20 and 22, as they are in the vanilla code.
913 *
914 * A packet is source-routed iff the uppermost bit
915 * of the first byte of the source address, at an
916 * offset of 8, has the uppermost bit set. If the
917 * packet is source-routed, the total number of bytes
918 * of routing information is 2 plus bits 0x1F00 of
919 * the 16-bit value at an offset of 14 (shifted right
920 * 8 - figure out which byte that is).
921 */
922 off_linktype = 14;
923 off_nl = 22; /* Token Ring+802.2+SNAP */
924 off_nl_nosnap = 17; /* Token Ring+802.2 */
925 return;
926
927 case DLT_IEEE802_11:
928 /*
929 * 802.11 doesn't really have a link-level type field.
930 * We set "off_linktype" to the offset of the LLC header.
931 *
932 * To check for Ethernet types, we assume that SSAP = SNAP
933 * is being used and pick out the encapsulated Ethernet type.
934 * XXX - should we generate code to check for SNAP?
935 *
936 * XXX - the header is actually variable-length. We
937 * assume a 24-byte link-layer header, as appears in
938 * data frames in networks with no bridges. If the
939 * fromds and tods 802.11 header bits are both set,
940 * it's actually supposed to be 30 bytes.
941 */
942 off_linktype = 24;
943 off_nl = 32; /* 802.11+802.2+SNAP */
944 off_nl_nosnap = 27; /* 802.11+802.2 */
945 return;
946
947 case DLT_PRISM_HEADER:
948 /*
949 * Same as 802.11, but with an additional header before
950 * the 802.11 header, containing a bunch of additional
951 * information including radio-level information.
952 *
953 * The header is 144 bytes long.
954 *
955 * XXX - same variable-length header problem; at least
956 * the Prism header is fixed-length.
957 */
958 off_ll = 144;
959 off_linktype = 144+24;
960 off_nl = 144+32; /* Prism+802.11+802.2+SNAP */
961 off_nl_nosnap = 144+27; /* Prism+802.11+802.2 */
962 return;
963
964 case DLT_IEEE802_11_RADIO_AVS:
965 /*
966 * Same as 802.11, but with an additional header before
967 * the 802.11 header, containing a bunch of additional
968 * information including radio-level information.
969 *
970 * The header is 64 bytes long, at least in its
971 * current incarnation.
972 *
973 * XXX - same variable-length header problem, only
974 * more so; this header is also variable-length,
975 * with the length being the 32-bit big-endian
976 * number at an offset of 4 from the beginning
977 * of the radio header.
978 */
979 off_ll = 64;
980 off_linktype = 64+24;
981 off_nl = 64+32; /* Radio+802.11+802.2+SNAP */
982 off_nl_nosnap = 64+27; /* Radio+802.11+802.2 */
983 return;
984
985 case DLT_IEEE802_11_RADIO:
986 /*
987 * Same as 802.11, but with an additional header before
988 * the 802.11 header, containing a bunch of additional
989 * information including radio-level information.
990 *
991 * The radiotap header is variable length, and we
992 * generate code to compute its length and store it
993 * in a register. These offsets are relative to the
994 * beginning of the 802.11 header.
995 */
996 off_linktype = 24;
997 off_nl = 32; /* 802.11+802.2+SNAP */
998 off_nl_nosnap = 27; /* 802.11+802.2 */
999 return;
1000
1001 case DLT_ATM_RFC1483:
1002 case DLT_ATM_CLIP: /* Linux ATM defines this */
1003 /*
1004 * assume routed, non-ISO PDUs
1005 * (i.e., LLC = 0xAA-AA-03, OUT = 0x00-00-00)
1006 *
1007 * XXX - what about ISO PDUs, e.g. CLNP, ISIS, ESIS,
1008 * or PPP with the PPP NLPID (e.g., PPPoA)? The
1009 * latter would presumably be treated the way PPPoE
1010 * should be, so you can do "pppoe and udp port 2049"
1011 * or "pppoa and tcp port 80" and have it check for
1012 * PPPo{A,E} and a PPP protocol of IP and....
1013 */
1014 off_linktype = 0;
1015 off_nl = 8; /* 802.2+SNAP */
1016 off_nl_nosnap = 3; /* 802.2 */
1017 return;
1018
1019 case DLT_SUNATM:
1020 /*
1021 * Full Frontal ATM; you get AALn PDUs with an ATM
1022 * pseudo-header.
1023 */
1024 is_atm = 1;
1025 off_vpi = SUNATM_VPI_POS;
1026 off_vci = SUNATM_VCI_POS;
1027 off_proto = PROTO_POS;
1028 off_mac = -1; /* LLC-encapsulated, so no MAC-layer header */
1029 off_payload = SUNATM_PKT_BEGIN_POS;
1030 off_linktype = off_payload;
1031 off_nl = off_payload+8; /* 802.2+SNAP */
1032 off_nl_nosnap = off_payload+3; /* 802.2 */
1033 return;
1034
1035 case DLT_RAW:
1036 off_linktype = -1;
1037 off_nl = 0;
1038 off_nl_nosnap = 0; /* no 802.2 LLC */
1039 return;
1040
1041 case DLT_LINUX_SLL: /* fake header for Linux cooked socket */
1042 off_linktype = 14;
1043 off_nl = 16;
1044 off_nl_nosnap = 16; /* no 802.2 LLC */
1045 return;
1046
1047 case DLT_LTALK:
1048 /*
1049 * LocalTalk does have a 1-byte type field in the LLAP header,
1050 * but really it just indicates whether there is a "short" or
1051 * "long" DDP packet following.
1052 */
1053 off_linktype = -1;
1054 off_nl = 0;
1055 off_nl_nosnap = 0; /* no 802.2 LLC */
1056 return;
1057
1058 case DLT_IP_OVER_FC:
1059 /*
1060 * RFC 2625 IP-over-Fibre-Channel doesn't really have a
1061 * link-level type field. We set "off_linktype" to the
1062 * offset of the LLC header.
1063 *
1064 * To check for Ethernet types, we assume that SSAP = SNAP
1065 * is being used and pick out the encapsulated Ethernet type.
1066 * XXX - should we generate code to check for SNAP? RFC
1067 * 2625 says SNAP should be used.
1068 */
1069 off_linktype = 16;
1070 off_nl = 24; /* IPFC+802.2+SNAP */
1071 off_nl_nosnap = 19; /* IPFC+802.2 */
1072 return;
1073
1074 case DLT_FRELAY:
1075 /*
1076 * XXX - we should set this to handle SNAP-encapsulated
1077 * frames (NLPID of 0x80).
1078 */
1079 off_linktype = -1;
1080 off_nl = 0;
1081 off_nl_nosnap = 0; /* no 802.2 LLC */
1082 return;
1083
1084 case DLT_APPLE_IP_OVER_IEEE1394:
1085 off_linktype = 16;
1086 off_nl = 18;
1087 off_nl_nosnap = 18; /* no 802.2 LLC */
1088 return;
1089
1090 case DLT_LINUX_IRDA:
1091 /*
1092 * Currently, only raw "link[N:M]" filtering is supported.
1093 */
1094 off_linktype = -1;
1095 off_nl = -1;
1096 off_nl_nosnap = -1;
1097 return;
1098
1099 case DLT_DOCSIS:
1100 /*
1101 * Currently, only raw "link[N:M]" filtering is supported.
1102 */
1103 off_linktype = -1;
1104 off_nl = -1;
1105 off_nl_nosnap = -1;
1106 return;
1107
1108 case DLT_SYMANTEC_FIREWALL:
1109 off_linktype = 6;
1110 off_nl = 44; /* Ethernet II */
1111 off_nl_nosnap = 44; /* XXX - what does it do with 802.3 packets? */
1112 return;
1113
1114 case DLT_PFLOG:
1115 off_linktype = 0;
1116 /* XXX read this from pf.h? */
1117 off_nl = PFLOG_HDRLEN;
1118 off_nl_nosnap = PFLOG_HDRLEN; /* no 802.2 LLC */
1119 return;
1120
1121 case DLT_JUNIPER_MFR:
1122 case DLT_JUNIPER_MLFR:
1123 case DLT_JUNIPER_MLPPP:
1124 case DLT_JUNIPER_PPP:
1125 case DLT_JUNIPER_CHDLC:
1126 case DLT_JUNIPER_FRELAY:
1127 off_linktype = 4;
1128 off_nl = 4;
1129 off_nl_nosnap = -1; /* no 802.2 LLC */
1130 return;
1131
1132 case DLT_JUNIPER_ATM1:
1133 off_linktype = 4; /* in reality variable between 4-8 */
1134 off_nl = 4;
1135 off_nl_nosnap = 14;
1136 return;
1137
1138 case DLT_JUNIPER_ATM2:
1139 off_linktype = 8; /* in reality variable between 8-12 */
1140 off_nl = 8;
1141 off_nl_nosnap = 18;
1142 return;
1143
1144 /* frames captured on a Juniper PPPoE service PIC
1145 * contain raw ethernet frames */
1146 case DLT_JUNIPER_PPPOE:
1147 case DLT_JUNIPER_ETHER:
1148 off_linktype = 16;
1149 off_nl = 18; /* Ethernet II */
1150 off_nl_nosnap = 21; /* 802.3+802.2 */
1151 return;
1152
1153 case DLT_JUNIPER_PPPOE_ATM:
1154 off_linktype = 4;
1155 off_nl = 6;
1156 off_nl_nosnap = -1; /* no 802.2 LLC */
1157 return;
1158
1159 case DLT_JUNIPER_GGSN:
1160 off_linktype = 6;
1161 off_nl = 12;
1162 off_nl_nosnap = -1; /* no 802.2 LLC */
1163 return;
1164
1165 case DLT_JUNIPER_ES:
1166 off_linktype = 6;
1167 off_nl = -1; /* not really a network layer but raw IP adresses */
1168 off_nl_nosnap = -1; /* no 802.2 LLC */
1169 return;
1170
1171 case DLT_JUNIPER_MONITOR:
1172 off_linktype = 12;
1173 off_nl = 12; /* raw IP/IP6 header */
1174 off_nl_nosnap = -1; /* no 802.2 LLC */
1175 return;
1176
1177 case DLT_JUNIPER_SERVICES:
1178 off_linktype = 12;
1179 off_nl = -1; /* L3 proto location dep. on cookie type */
1180 off_nl_nosnap = -1; /* no 802.2 LLC */
1181 return;
1182
1183 case DLT_MTP2:
1184 off_sio = 3;
1185 off_opc = 4;
1186 off_dpc = 4;
1187 off_sls = 7;
1188 off_linktype = -1;
1189 off_nl = -1;
1190 off_nl_nosnap = -1;
1191 return;
1192
1193 #ifdef DLT_PFSYNC
1194 case DLT_PFSYNC:
1195 off_linktype = -1;
1196 off_nl = 4;
1197 off_nl_nosnap = 4;
1198 return;
1199 #endif
1200
1201 case DLT_LINUX_LAPD:
1202 /*
1203 * Currently, only raw "link[N:M]" filtering is supported.
1204 */
1205 off_linktype = -1;
1206 off_nl = -1;
1207 off_nl_nosnap = -1;
1208 return;
1209 }
1210 bpf_error("unknown data link type %d", linktype);
1211 /* NOTREACHED */
1212 }
1213
1214 /*
1215 * Load a value relative to the beginning of the link-layer header.
1216 * The link-layer header doesn't necessarily begin at the beginning
1217 * of the packet data; there might be a variable-length prefix containing
1218 * radio information.
1219 */
1220 static struct slist *
1221 gen_load_llrel(offset, size)
1222 u_int offset, size;
1223 {
1224 struct slist *s, *s2;
1225
1226 s = gen_llprefixlen();
1227
1228 /*
1229 * If "s" is non-null, it has code to arrange that the X register
1230 * contains the length of the prefix preceding the link-layer
1231 * header.
1232 */
1233 if (s != NULL) {
1234 s2 = new_stmt(BPF_LD|BPF_IND|size);
1235 s2->s.k = offset;
1236 sappend(s, s2);
1237 } else {
1238 s = new_stmt(BPF_LD|BPF_ABS|size);
1239 s->s.k = offset;
1240 }
1241 return s;
1242 }
1243
1244 /*
1245 * Load a value relative to the beginning of the specified header.
1246 */
1247 static struct slist *
1248 gen_load_a(offrel, offset, size)
1249 enum e_offrel offrel;
1250 u_int offset, size;
1251 {
1252 struct slist *s, *s2;
1253
1254 switch (offrel) {
1255
1256 case OR_PACKET:
1257 s = gen_load_llrel(offset, size);
1258 break;
1259
1260 case OR_LINK:
1261 s = gen_load_llrel(off_ll + offset, size);
1262 break;
1263
1264 case OR_NET:
1265 s = gen_load_llrel(off_nl + offset, size);
1266 break;
1267
1268 case OR_NET_NOSNAP:
1269 s = gen_load_llrel(off_nl_nosnap + offset, size);
1270 break;
1271
1272 case OR_TRAN_IPV4:
1273 /*
1274 * Load the X register with the length of the IPv4 header,
1275 * in bytes.
1276 */
1277 s = gen_loadx_iphdrlen();
1278
1279 /*
1280 * Load the item at {length of the link-layer header} +
1281 * {length of the IPv4 header} + {specified offset}.
1282 */
1283 s2 = new_stmt(BPF_LD|BPF_IND|size);
1284 s2->s.k = off_nl + offset;
1285 sappend(s, s2);
1286 break;
1287
1288 case OR_TRAN_IPV6:
1289 s = gen_load_llrel(off_nl + 40 + offset, size);
1290 break;
1291
1292 default:
1293 abort();
1294 return NULL;
1295 }
1296 return s;
1297 }
1298
1299 /*
1300 * Generate code to load into the X register the sum of the length of
1301 * the IPv4 header and any variable-length header preceding the link-layer
1302 * header.
1303 */
1304 static struct slist *
1305 gen_loadx_iphdrlen()
1306 {
1307 struct slist *s, *s2;
1308
1309 s = gen_llprefixlen();
1310 if (s != NULL) {
1311 /*
1312 * There's a variable-length prefix preceding the
1313 * link-layer header. "s" points to a list of statements
1314 * that put the length of that prefix into the X register.
1315 * The 4*([k]&0xf) addressing mode can't be used, as we
1316 * don't have a constant offset, so we have to load the
1317 * value in question into the A register and add to it
1318 * the value from the X register.
1319 */
1320 s2 = new_stmt(BPF_LD|BPF_IND|BPF_B);
1321 s2->s.k = off_nl;
1322 sappend(s, s2);
1323 s2 = new_stmt(BPF_ALU|BPF_AND|BPF_K);
1324 s2->s.k = 0xf;
1325 sappend(s, s2);
1326 s2 = new_stmt(BPF_ALU|BPF_LSH|BPF_K);
1327 s2->s.k = 2;
1328 sappend(s, s2);
1329
1330 /*
1331 * The A register now contains the length of the
1332 * IP header. We need to add to it the length
1333 * of the prefix preceding the link-layer
1334 * header, which is still in the X register, and
1335 * move the result into the X register.
1336 */
1337 sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X));
1338 sappend(s, new_stmt(BPF_MISC|BPF_TAX));
1339 } else {
1340 /*
1341 * There is no variable-length header preceding the
1342 * link-layer header; if there's a fixed-length
1343 * header preceding it, its length is included in
1344 * the off_ variables, so it doesn't need to be added.
1345 */
1346 s = new_stmt(BPF_LDX|BPF_MSH|BPF_B);
1347 s->s.k = off_nl;
1348 }
1349 return s;
1350 }
1351
1352 static struct block *
1353 gen_uncond(rsense)
1354 int rsense;
1355 {
1356 struct block *b;
1357 struct slist *s;
1358
1359 s = new_stmt(BPF_LD|BPF_IMM);
1360 s->s.k = !rsense;
1361 b = new_block(JMP(BPF_JEQ));
1362 b->stmts = s;
1363
1364 return b;
1365 }
1366
1367 static inline struct block *
1368 gen_true()
1369 {
1370 return gen_uncond(1);
1371 }
1372
1373 static inline struct block *
1374 gen_false()
1375 {
1376 return gen_uncond(0);
1377 }
1378
1379 /*
1380 * Byte-swap a 32-bit number.
1381 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
1382 * big-endian platforms.)
1383 */
1384 #define SWAPLONG(y) \
1385 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
1386
1387 /*
1388 * Generate code to match a particular packet type.
1389 *
1390 * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
1391 * value, if <= ETHERMTU. We use that to determine whether to
1392 * match the type/length field or to check the type/length field for
1393 * a value <= ETHERMTU to see whether it's a type field and then do
1394 * the appropriate test.
1395 */
1396 static struct block *
1397 gen_ether_linktype(proto)
1398 register int proto;
1399 {
1400 struct block *b0, *b1;
1401
1402 switch (proto) {
1403
1404 case LLCSAP_ISONS:
1405 case LLCSAP_IP:
1406 case LLCSAP_NETBEUI:
1407 /*
1408 * OSI protocols and NetBEUI always use 802.2 encapsulation,
1409 * so we check the DSAP and SSAP.
1410 *
1411 * LLCSAP_IP checks for IP-over-802.2, rather
1412 * than IP-over-Ethernet or IP-over-SNAP.
1413 *
1414 * XXX - should we check both the DSAP and the
1415 * SSAP, like this, or should we check just the
1416 * DSAP, as we do for other types <= ETHERMTU
1417 * (i.e., other SAP values)?
1418 */
1419 b0 = gen_cmp_gt(OR_LINK, off_linktype, BPF_H, ETHERMTU);
1420 gen_not(b0);
1421 b1 = gen_cmp(OR_LINK, off_linktype + 2, BPF_H, (bpf_int32)
1422 ((proto << 8) | proto));
1423 gen_and(b0, b1);
1424 return b1;
1425
1426 case LLCSAP_IPX:
1427 /*
1428 * Check for;
1429 *
1430 * Ethernet_II frames, which are Ethernet
1431 * frames with a frame type of ETHERTYPE_IPX;
1432 *
1433 * Ethernet_802.3 frames, which are 802.3
1434 * frames (i.e., the type/length field is
1435 * a length field, <= ETHERMTU, rather than
1436 * a type field) with the first two bytes
1437 * after the Ethernet/802.3 header being
1438 * 0xFFFF;
1439 *
1440 * Ethernet_802.2 frames, which are 802.3
1441 * frames with an 802.2 LLC header and
1442 * with the IPX LSAP as the DSAP in the LLC
1443 * header;
1444 *
1445 * Ethernet_SNAP frames, which are 802.3
1446 * frames with an LLC header and a SNAP
1447 * header and with an OUI of 0x000000
1448 * (encapsulated Ethernet) and a protocol
1449 * ID of ETHERTYPE_IPX in the SNAP header.
1450 *
1451 * XXX - should we generate the same code both
1452 * for tests for LLCSAP_IPX and for ETHERTYPE_IPX?
1453 */
1454
1455 /*
1456 * This generates code to check both for the
1457 * IPX LSAP (Ethernet_802.2) and for Ethernet_802.3.
1458 */
1459 b0 = gen_cmp(OR_LINK, off_linktype + 2, BPF_B,
1460 (bpf_int32)LLCSAP_IPX);
1461 b1 = gen_cmp(OR_LINK, off_linktype + 2, BPF_H,
1462 (bpf_int32)0xFFFF);
1463 gen_or(b0, b1);
1464
1465 /*
1466 * Now we add code to check for SNAP frames with
1467 * ETHERTYPE_IPX, i.e. Ethernet_SNAP.
1468 */
1469 b0 = gen_snap(0x000000, ETHERTYPE_IPX, 14);
1470 gen_or(b0, b1);
1471
1472 /*
1473 * Now we generate code to check for 802.3
1474 * frames in general.
1475 */
1476 b0 = gen_cmp_gt(OR_LINK, off_linktype, BPF_H, ETHERMTU);
1477 gen_not(b0);
1478
1479 /*
1480 * Now add the check for 802.3 frames before the
1481 * check for Ethernet_802.2 and Ethernet_802.3,
1482 * as those checks should only be done on 802.3
1483 * frames, not on Ethernet frames.
1484 */
1485 gen_and(b0, b1);
1486
1487 /*
1488 * Now add the check for Ethernet_II frames, and
1489 * do that before checking for the other frame
1490 * types.
1491 */
1492 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H,
1493 (bpf_int32)ETHERTYPE_IPX);
1494 gen_or(b0, b1);
1495 return b1;
1496
1497 case ETHERTYPE_ATALK:
1498 case ETHERTYPE_AARP:
1499 /*
1500 * EtherTalk (AppleTalk protocols on Ethernet link
1501 * layer) may use 802.2 encapsulation.
1502 */
1503
1504 /*
1505 * Check for 802.2 encapsulation (EtherTalk phase 2?);
1506 * we check for an Ethernet type field less than
1507 * 1500, which means it's an 802.3 length field.
1508 */
1509 b0 = gen_cmp_gt(OR_LINK, off_linktype, BPF_H, ETHERMTU);
1510 gen_not(b0);
1511
1512 /*
1513 * 802.2-encapsulated ETHERTYPE_ATALK packets are
1514 * SNAP packets with an organization code of
1515 * 0x080007 (Apple, for Appletalk) and a protocol
1516 * type of ETHERTYPE_ATALK (Appletalk).
1517 *
1518 * 802.2-encapsulated ETHERTYPE_AARP packets are
1519 * SNAP packets with an organization code of
1520 * 0x000000 (encapsulated Ethernet) and a protocol
1521 * type of ETHERTYPE_AARP (Appletalk ARP).
1522 */
1523 if (proto == ETHERTYPE_ATALK)
1524 b1 = gen_snap(0x080007, ETHERTYPE_ATALK, 14);
1525 else /* proto == ETHERTYPE_AARP */
1526 b1 = gen_snap(0x000000, ETHERTYPE_AARP, 14);
1527 gen_and(b0, b1);
1528
1529 /*
1530 * Check for Ethernet encapsulation (Ethertalk
1531 * phase 1?); we just check for the Ethernet
1532 * protocol type.
1533 */
1534 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32)proto);
1535
1536 gen_or(b0, b1);
1537 return b1;
1538
1539 default:
1540 if (proto <= ETHERMTU) {
1541 /*
1542 * This is an LLC SAP value, so the frames
1543 * that match would be 802.2 frames.
1544 * Check that the frame is an 802.2 frame
1545 * (i.e., that the length/type field is
1546 * a length field, <= ETHERMTU) and
1547 * then check the DSAP.
1548 */
1549 b0 = gen_cmp_gt(OR_LINK, off_linktype, BPF_H, ETHERMTU);
1550 gen_not(b0);
1551 b1 = gen_cmp(OR_LINK, off_linktype + 2, BPF_B,
1552 (bpf_int32)proto);
1553 gen_and(b0, b1);
1554 return b1;
1555 } else {
1556 /*
1557 * This is an Ethernet type, so compare
1558 * the length/type field with it (if
1559 * the frame is an 802.2 frame, the length
1560 * field will be <= ETHERMTU, and, as
1561 * "proto" is > ETHERMTU, this test
1562 * will fail and the frame won't match,
1563 * which is what we want).
1564 */
1565 return gen_cmp(OR_LINK, off_linktype, BPF_H,
1566 (bpf_int32)proto);
1567 }
1568 }
1569 }
1570
1571 /*
1572 * Generate code to match a particular packet type.
1573 *
1574 * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
1575 * value, if <= ETHERMTU. We use that to determine whether to
1576 * match the type field or to check the type field for the special
1577 * LINUX_SLL_P_802_2 value and then do the appropriate test.
1578 */
1579 static struct block *
1580 gen_linux_sll_linktype(proto)
1581 register int proto;
1582 {
1583 struct block *b0, *b1;
1584
1585 switch (proto) {
1586
1587 case LLCSAP_ISONS:
1588 case LLCSAP_IP:
1589 case LLCSAP_NETBEUI:
1590 /*
1591 * OSI protocols and NetBEUI always use 802.2 encapsulation,
1592 * so we check the DSAP and SSAP.
1593 *
1594 * LLCSAP_IP checks for IP-over-802.2, rather
1595 * than IP-over-Ethernet or IP-over-SNAP.
1596 *
1597 * XXX - should we check both the DSAP and the
1598 * SSAP, like this, or should we check just the
1599 * DSAP, as we do for other types <= ETHERMTU
1600 * (i.e., other SAP values)?
1601 */
1602 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_2);
1603 b1 = gen_cmp(OR_LINK, off_linktype + 2, BPF_H, (bpf_int32)
1604 ((proto << 8) | proto));
1605 gen_and(b0, b1);
1606 return b1;
1607
1608 case LLCSAP_IPX:
1609 /*
1610 * Ethernet_II frames, which are Ethernet
1611 * frames with a frame type of ETHERTYPE_IPX;
1612 *
1613 * Ethernet_802.3 frames, which have a frame
1614 * type of LINUX_SLL_P_802_3;
1615 *
1616 * Ethernet_802.2 frames, which are 802.3
1617 * frames with an 802.2 LLC header (i.e, have
1618 * a frame type of LINUX_SLL_P_802_2) and
1619 * with the IPX LSAP as the DSAP in the LLC
1620 * header;
1621 *
1622 * Ethernet_SNAP frames, which are 802.3
1623 * frames with an LLC header and a SNAP
1624 * header and with an OUI of 0x000000
1625 * (encapsulated Ethernet) and a protocol
1626 * ID of ETHERTYPE_IPX in the SNAP header.
1627 *
1628 * First, do the checks on LINUX_SLL_P_802_2
1629 * frames; generate the check for either
1630 * Ethernet_802.2 or Ethernet_SNAP frames, and
1631 * then put a check for LINUX_SLL_P_802_2 frames
1632 * before it.
1633 */
1634 b0 = gen_cmp(OR_LINK, off_linktype + 2, BPF_B,
1635 (bpf_int32)LLCSAP_IPX);
1636 b1 = gen_snap(0x000000, ETHERTYPE_IPX,
1637 off_linktype + 2);
1638 gen_or(b0, b1);
1639 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_2);
1640 gen_and(b0, b1);
1641
1642 /*
1643 * Now check for 802.3 frames and OR that with
1644 * the previous test.
1645 */
1646 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_3);
1647 gen_or(b0, b1);
1648
1649 /*
1650 * Now add the check for Ethernet_II frames, and
1651 * do that before checking for the other frame
1652 * types.
1653 */
1654 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H,
1655 (bpf_int32)ETHERTYPE_IPX);
1656 gen_or(b0, b1);
1657 return b1;
1658
1659 case ETHERTYPE_ATALK:
1660 case ETHERTYPE_AARP:
1661 /*
1662 * EtherTalk (AppleTalk protocols on Ethernet link
1663 * layer) may use 802.2 encapsulation.
1664 */
1665
1666 /*
1667 * Check for 802.2 encapsulation (EtherTalk phase 2?);
1668 * we check for the 802.2 protocol type in the
1669 * "Ethernet type" field.
1670 */
1671 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_2);
1672
1673 /*
1674 * 802.2-encapsulated ETHERTYPE_ATALK packets are
1675 * SNAP packets with an organization code of
1676 * 0x080007 (Apple, for Appletalk) and a protocol
1677 * type of ETHERTYPE_ATALK (Appletalk).
1678 *
1679 * 802.2-encapsulated ETHERTYPE_AARP packets are
1680 * SNAP packets with an organization code of
1681 * 0x000000 (encapsulated Ethernet) and a protocol
1682 * type of ETHERTYPE_AARP (Appletalk ARP).
1683 */
1684 if (proto == ETHERTYPE_ATALK)
1685 b1 = gen_snap(0x080007, ETHERTYPE_ATALK,
1686 off_linktype + 2);
1687 else /* proto == ETHERTYPE_AARP */
1688 b1 = gen_snap(0x000000, ETHERTYPE_AARP,
1689 off_linktype + 2);
1690 gen_and(b0, b1);
1691
1692 /*
1693 * Check for Ethernet encapsulation (Ethertalk
1694 * phase 1?); we just check for the Ethernet
1695 * protocol type.
1696 */
1697 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32)proto);
1698
1699 gen_or(b0, b1);
1700 return b1;
1701
1702 default:
1703 if (proto <= ETHERMTU) {
1704 /*
1705 * This is an LLC SAP value, so the frames
1706 * that match would be 802.2 frames.
1707 * Check for the 802.2 protocol type
1708 * in the "Ethernet type" field, and
1709 * then check the DSAP.
1710 */
1711 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H,
1712 LINUX_SLL_P_802_2);
1713 b1 = gen_cmp(OR_LINK, off_linktype + 2, BPF_B,
1714 (bpf_int32)proto);
1715 gen_and(b0, b1);
1716 return b1;
1717 } else {
1718 /*
1719 * This is an Ethernet type, so compare
1720 * the length/type field with it (if
1721 * the frame is an 802.2 frame, the length
1722 * field will be <= ETHERMTU, and, as
1723 * "proto" is > ETHERMTU, this test
1724 * will fail and the frame won't match,
1725 * which is what we want).
1726 */
1727 return gen_cmp(OR_LINK, off_linktype, BPF_H,
1728 (bpf_int32)proto);
1729 }
1730 }
1731 }
1732
1733 static void
1734 insert_radiotap_load_llprefixlen(b)
1735 struct block *b;
1736 {
1737 struct slist *s1, *s2;
1738
1739 /*
1740 * Prepend to the statements in this block code to load the
1741 * length of the radiotap header into the register assigned
1742 * to hold that length, if one has been assigned.
1743 */
1744 if (reg_ll_size != -1) {
1745 /*
1746 * The 2 bytes at offsets of 2 and 3 from the beginning
1747 * of the radiotap header are the length of the radiotap
1748 * header; unfortunately, it's little-endian, so we have
1749 * to load it a byte at a time and construct the value.
1750 */
1751
1752 /*
1753 * Load the high-order byte, at an offset of 3, shift it
1754 * left a byte, and put the result in the X register.
1755 */
1756 s1 = new_stmt(BPF_LD|BPF_B|BPF_ABS);
1757 s1->s.k = 3;
1758 s2 = new_stmt(BPF_ALU|BPF_LSH|BPF_K);
1759 sappend(s1, s2);
1760 s2->s.k = 8;
1761 s2 = new_stmt(BPF_MISC|BPF_TAX);
1762 sappend(s1, s2);
1763
1764 /*
1765 * Load the next byte, at an offset of 2, and OR the
1766 * value from the X register into it.
1767 */
1768 s2 = new_stmt(BPF_LD|BPF_B|BPF_ABS);
1769 sappend(s1, s2);
1770 s2->s.k = 2;
1771 s2 = new_stmt(BPF_ALU|BPF_OR|BPF_X);
1772 sappend(s1, s2);
1773
1774 /*
1775 * Now allocate a register to hold that value and store
1776 * it.
1777 */
1778 s2 = new_stmt(BPF_ST);
1779 s2->s.k = reg_ll_size;
1780 sappend(s1, s2);
1781
1782 /*
1783 * Now move it into the X register.
1784 */
1785 s2 = new_stmt(BPF_MISC|BPF_TAX);
1786 sappend(s1, s2);
1787
1788 /*
1789 * Now append all the existing statements in this
1790 * block to these statements.
1791 */
1792 sappend(s1, b->stmts);
1793 b->stmts = s1;
1794 }
1795 }
1796
1797
1798 static void
1799 insert_load_llprefixlen(b)
1800 struct block *b;
1801 {
1802 switch (linktype) {
1803
1804 case DLT_IEEE802_11_RADIO:
1805 insert_radiotap_load_llprefixlen(b);
1806 }
1807 }
1808
1809
1810 static struct slist *
1811 gen_radiotap_llprefixlen(void)
1812 {
1813 struct slist *s;
1814
1815 if (reg_ll_size == -1) {
1816 /*
1817 * We haven't yet assigned a register for the length
1818 * of the radiotap header; allocate one.
1819 */
1820 reg_ll_size = alloc_reg();
1821 }
1822
1823 /*
1824 * Load the register containing the radiotap length
1825 * into the X register.
1826 */
1827 s = new_stmt(BPF_LDX|BPF_MEM);
1828 s->s.k = reg_ll_size;
1829 return s;
1830 }
1831
1832 /*
1833 * Generate code to compute the link-layer header length, if necessary,
1834 * putting it into the X register, and to return either a pointer to a
1835 * "struct slist" for the list of statements in that code, or NULL if
1836 * no code is necessary.
1837 */
1838 static struct slist *
1839 gen_llprefixlen(void)
1840 {
1841 switch (linktype) {
1842
1843 case DLT_IEEE802_11_RADIO:
1844 return gen_radiotap_llprefixlen();
1845
1846 default:
1847 return NULL;
1848 }
1849 }
1850
1851 /*
1852 * Generate code to match a particular packet type by matching the
1853 * link-layer type field or fields in the 802.2 LLC header.
1854 *
1855 * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
1856 * value, if <= ETHERMTU.
1857 */
1858 static struct block *
1859 gen_linktype(proto)
1860 register int proto;
1861 {
1862 struct block *b0, *b1, *b2;
1863
1864 /* are we checking MPLS-encapsulated packets? */
1865 if (label_stack_depth > 0) {
1866 switch (proto) {
1867 case ETHERTYPE_IP:
1868 case PPP_IP:
1869 /* FIXME add other L3 proto IDs */
1870 return gen_mpls_linktype(Q_IP);
1871
1872 case ETHERTYPE_IPV6:
1873 case PPP_IPV6:
1874 /* FIXME add other L3 proto IDs */
1875 return gen_mpls_linktype(Q_IPV6);
1876
1877 default:
1878 bpf_error("unsupported protocol over mpls");
1879 /* NOTREACHED */
1880 }
1881 }
1882
1883 switch (linktype) {
1884
1885 case DLT_EN10MB:
1886 return gen_ether_linktype(proto);
1887 /*NOTREACHED*/
1888 break;
1889
1890 case DLT_C_HDLC:
1891 switch (proto) {
1892
1893 case LLCSAP_ISONS:
1894 proto = (proto << 8 | LLCSAP_ISONS);
1895 /* fall through */
1896
1897 default:
1898 return gen_cmp(OR_LINK, off_linktype, BPF_H,
1899 (bpf_int32)proto);
1900 /*NOTREACHED*/
1901 break;
1902 }
1903 break;
1904
1905 case DLT_FDDI:
1906 case DLT_IEEE802:
1907 case DLT_IEEE802_11:
1908 case DLT_IEEE802_11_RADIO_AVS:
1909 case DLT_IEEE802_11_RADIO:
1910 case DLT_PRISM_HEADER:
1911 case DLT_ATM_RFC1483:
1912 case DLT_ATM_CLIP:
1913 case DLT_IP_OVER_FC:
1914 return gen_llc_linktype(proto);
1915 /*NOTREACHED*/
1916 break;
1917
1918 case DLT_SUNATM:
1919 /*
1920 * If "is_lane" is set, check for a LANE-encapsulated
1921 * version of this protocol, otherwise check for an
1922 * LLC-encapsulated version of this protocol.
1923 *
1924 * We assume LANE means Ethernet, not Token Ring.
1925 */
1926 if (is_lane) {
1927 /*
1928 * Check that the packet doesn't begin with an
1929 * LE Control marker. (We've already generated
1930 * a test for LANE.)
1931 */
1932 b0 = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS, BPF_H,
1933 0xFF00);
1934 gen_not(b0);
1935
1936 /*
1937 * Now generate an Ethernet test.
1938 */
1939 b1 = gen_ether_linktype(proto);
1940 gen_and(b0, b1);
1941 return b1;
1942 } else {
1943 /*
1944 * Check for LLC encapsulation and then check the
1945 * protocol.
1946 */
1947 b0 = gen_atmfield_code(A_PROTOTYPE, PT_LLC, BPF_JEQ, 0);
1948 b1 = gen_llc_linktype(proto);
1949 gen_and(b0, b1);
1950 return b1;
1951 }
1952 /*NOTREACHED*/
1953 break;
1954
1955 case DLT_LINUX_SLL:
1956 return gen_linux_sll_linktype(proto);
1957 /*NOTREACHED*/
1958 break;
1959
1960 case DLT_SLIP:
1961 case DLT_SLIP_BSDOS:
1962 case DLT_RAW:
1963 /*
1964 * These types don't provide any type field; packets
1965 * are always IP.
1966 *
1967 * XXX - for IPv4, check for a version number of 4, and,
1968 * for IPv6, check for a version number of 6?
1969 */
1970 switch (proto) {
1971
1972 case ETHERTYPE_IP:
1973 #ifdef INET6
1974 case ETHERTYPE_IPV6:
1975 #endif
1976 return gen_true(); /* always true */
1977
1978 default:
1979 return gen_false(); /* always false */
1980 }
1981 /*NOTREACHED*/
1982 break;
1983
1984 case DLT_PPP:
1985 case DLT_PPP_PPPD:
1986 case DLT_PPP_SERIAL:
1987 case DLT_PPP_ETHER:
1988 /*
1989 * We use Ethernet protocol types inside libpcap;
1990 * map them to the corresponding PPP protocol types.
1991 */
1992 switch (proto) {
1993
1994 case ETHERTYPE_IP:
1995 proto = PPP_IP;
1996 break;
1997
1998 #ifdef INET6
1999 case ETHERTYPE_IPV6:
2000 proto = PPP_IPV6;
2001 break;
2002 #endif
2003
2004 case ETHERTYPE_DN:
2005 proto = PPP_DECNET;
2006 break;
2007
2008 case ETHERTYPE_ATALK:
2009 proto = PPP_APPLE;
2010 break;
2011
2012 case ETHERTYPE_NS:
2013 proto = PPP_NS;
2014 break;
2015
2016 case LLCSAP_ISONS:
2017 proto = PPP_OSI;
2018 break;
2019
2020 case LLCSAP_8021D:
2021 /*
2022 * I'm assuming the "Bridging PDU"s that go
2023 * over PPP are Spanning Tree Protocol
2024 * Bridging PDUs.
2025 */
2026 proto = PPP_BRPDU;
2027 break;
2028
2029 case LLCSAP_IPX:
2030 proto = PPP_IPX;
2031 break;
2032 }
2033 break;
2034
2035 case DLT_PPP_BSDOS:
2036 /*
2037 * We use Ethernet protocol types inside libpcap;
2038 * map them to the corresponding PPP protocol types.
2039 */
2040 switch (proto) {
2041
2042 case ETHERTYPE_IP:
2043 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, PPP_IP);
2044 b1 = gen_cmp(OR_LINK, off_linktype, BPF_H, PPP_VJC);
2045 gen_or(b0, b1);
2046 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, PPP_VJNC);
2047 gen_or(b1, b0);
2048 return b0;
2049
2050 #ifdef INET6
2051 case ETHERTYPE_IPV6:
2052 proto = PPP_IPV6;
2053 /* more to go? */
2054 break;
2055 #endif
2056
2057 case ETHERTYPE_DN:
2058 proto = PPP_DECNET;
2059 break;
2060
2061 case ETHERTYPE_ATALK:
2062 proto = PPP_APPLE;
2063 break;
2064
2065 case ETHERTYPE_NS:
2066 proto = PPP_NS;
2067 break;
2068
2069 case LLCSAP_ISONS:
2070 proto = PPP_OSI;
2071 break;
2072
2073 case LLCSAP_8021D:
2074 /*
2075 * I'm assuming the "Bridging PDU"s that go
2076 * over PPP are Spanning Tree Protocol
2077 * Bridging PDUs.
2078 */
2079 proto = PPP_BRPDU;
2080 break;
2081
2082 case LLCSAP_IPX:
2083 proto = PPP_IPX;
2084 break;
2085 }
2086 break;
2087
2088 case DLT_NULL:
2089 case DLT_LOOP:
2090 case DLT_ENC:
2091 /*
2092 * For DLT_NULL, the link-layer header is a 32-bit
2093 * word containing an AF_ value in *host* byte order,
2094 * and for DLT_ENC, the link-layer header begins
2095 * with a 32-bit work containing an AF_ value in
2096 * host byte order.
2097 *
2098 * In addition, if we're reading a saved capture file,
2099 * the host byte order in the capture may not be the
2100 * same as the host byte order on this machine.
2101 *
2102 * For DLT_LOOP, the link-layer header is a 32-bit
2103 * word containing an AF_ value in *network* byte order.
2104 *
2105 * XXX - AF_ values may, unfortunately, be platform-
2106 * dependent; for example, FreeBSD's AF_INET6 is 24
2107 * whilst NetBSD's and OpenBSD's is 26.
2108 *
2109 * This means that, when reading a capture file, just
2110 * checking for our AF_INET6 value won't work if the
2111 * capture file came from another OS.
2112 */
2113 switch (proto) {
2114
2115 case ETHERTYPE_IP:
2116 proto = AF_INET;
2117 break;
2118
2119 #ifdef INET6
2120 case ETHERTYPE_IPV6:
2121 proto = AF_INET6;
2122 break;
2123 #endif
2124
2125 default:
2126 /*
2127 * Not a type on which we support filtering.
2128 * XXX - support those that have AF_ values
2129 * #defined on this platform, at least?
2130 */
2131 return gen_false();
2132 }
2133
2134 if (linktype == DLT_NULL || linktype == DLT_ENC) {
2135 /*
2136 * The AF_ value is in host byte order, but
2137 * the BPF interpreter will convert it to
2138 * network byte order.
2139 *
2140 * If this is a save file, and it's from a
2141 * machine with the opposite byte order to
2142 * ours, we byte-swap the AF_ value.
2143 *
2144 * Then we run it through "htonl()", and
2145 * generate code to compare against the result.
2146 */
2147 if (bpf_pcap->sf.rfile != NULL &&
2148 bpf_pcap->sf.swapped)
2149 proto = SWAPLONG(proto);
2150 proto = htonl(proto);
2151 }
2152 return (gen_cmp(OR_LINK, 0, BPF_W, (bpf_int32)proto));
2153
2154 case DLT_PFLOG:
2155 /*
2156 * af field is host byte order in contrast to the rest of
2157 * the packet.
2158 */
2159 if (proto == ETHERTYPE_IP)
2160 return (gen_cmp(OR_LINK, offsetof(struct pfloghdr, af),
2161 BPF_B, (bpf_int32)AF_INET));
2162 #ifdef INET6
2163 else if (proto == ETHERTYPE_IPV6)
2164 return (gen_cmp(OR_LINK, offsetof(struct pfloghdr, af),
2165 BPF_B, (bpf_int32)AF_INET6));
2166 #endif /* INET6 */
2167 else
2168 return gen_false();
2169 /*NOTREACHED*/
2170 break;
2171
2172 case DLT_ARCNET:
2173 case DLT_ARCNET_LINUX:
2174 /*
2175 * XXX should we check for first fragment if the protocol
2176 * uses PHDS?
2177 */
2178 switch (proto) {
2179
2180 default:
2181 return gen_false();
2182
2183 #ifdef INET6
2184 case ETHERTYPE_IPV6:
2185 return (gen_cmp(OR_LINK, off_linktype, BPF_B,
2186 (bpf_int32)ARCTYPE_INET6));
2187 #endif /* INET6 */
2188
2189 case ETHERTYPE_IP:
2190 b0 = gen_cmp(OR_LINK, off_linktype, BPF_B,
2191 (bpf_int32)ARCTYPE_IP);
2192 b1 = gen_cmp(OR_LINK, off_linktype, BPF_B,
2193 (bpf_int32)ARCTYPE_IP_OLD);
2194 gen_or(b0, b1);
2195 return (b1);
2196
2197 case ETHERTYPE_ARP:
2198 b0 = gen_cmp(OR_LINK, off_linktype, BPF_B,
2199 (bpf_int32)ARCTYPE_ARP);
2200 b1 = gen_cmp(OR_LINK, off_linktype, BPF_B,
2201 (bpf_int32)ARCTYPE_ARP_OLD);
2202 gen_or(b0, b1);
2203 return (b1);
2204
2205 case ETHERTYPE_REVARP:
2206 return (gen_cmp(OR_LINK, off_linktype, BPF_B,
2207 (bpf_int32)ARCTYPE_REVARP));
2208
2209 case ETHERTYPE_ATALK:
2210 return (gen_cmp(OR_LINK, off_linktype, BPF_B,
2211 (bpf_int32)ARCTYPE_ATALK));
2212 }
2213 /*NOTREACHED*/
2214 break;
2215
2216 case DLT_LTALK:
2217 switch (proto) {
2218 case ETHERTYPE_ATALK:
2219 return gen_true();
2220 default:
2221 return gen_false();
2222 }
2223 /*NOTREACHED*/
2224 break;
2225
2226 case DLT_FRELAY:
2227 /*
2228 * XXX - assumes a 2-byte Frame Relay header with
2229 * DLCI and flags. What if the address is longer?
2230 */
2231 switch (proto) {
2232
2233 case ETHERTYPE_IP:
2234 /*
2235 * Check for the special NLPID for IP.
2236 */
2237 return gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | 0xcc);
2238
2239 #ifdef INET6
2240 case ETHERTYPE_IPV6:
2241 /*
2242 * Check for the special NLPID for IPv6.
2243 */
2244 return gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | 0x8e);
2245 #endif
2246
2247 case LLCSAP_ISONS:
2248 /*
2249 * Check for several OSI protocols.
2250 *
2251 * Frame Relay packets typically have an OSI
2252 * NLPID at the beginning; we check for each
2253 * of them.
2254 *
2255 * What we check for is the NLPID and a frame
2256 * control field of UI, i.e. 0x03 followed
2257 * by the NLPID.
2258 */
2259 b0 = gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | ISO8473_CLNP);
2260 b1 = gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | ISO9542_ESIS);
2261 b2 = gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | ISO10589_ISIS);
2262 gen_or(b1, b2);
2263 gen_or(b0, b2);
2264 return b2;
2265
2266 default:
2267 return gen_false();
2268 }
2269 /*NOTREACHED*/
2270 break;
2271
2272 case DLT_JUNIPER_MFR:
2273 case DLT_JUNIPER_MLFR:
2274 case DLT_JUNIPER_MLPPP:
2275 case DLT_JUNIPER_ATM1:
2276 case DLT_JUNIPER_ATM2:
2277 case DLT_JUNIPER_PPPOE:
2278 case DLT_JUNIPER_PPPOE_ATM:
2279 case DLT_JUNIPER_GGSN:
2280 case DLT_JUNIPER_ES:
2281 case DLT_JUNIPER_MONITOR:
2282 case DLT_JUNIPER_SERVICES:
2283 case DLT_JUNIPER_ETHER:
2284 case DLT_JUNIPER_PPP:
2285 case DLT_JUNIPER_FRELAY:
2286 case DLT_JUNIPER_CHDLC:
2287 /* just lets verify the magic number for now -
2288 * on ATM we may have up to 6 different encapsulations on the wire
2289 * and need a lot of heuristics to figure out that the payload
2290 * might be;
2291 *
2292 * FIXME encapsulation specific BPF_ filters
2293 */
2294 return gen_mcmp(OR_LINK, 0, BPF_W, 0x4d474300, 0xffffff00); /* compare the magic number */
2295
2296 case DLT_LINUX_IRDA:
2297 bpf_error("IrDA link-layer type filtering not implemented");
2298
2299 case DLT_DOCSIS:
2300 bpf_error("DOCSIS link-layer type filtering not implemented");
2301
2302 case DLT_LINUX_LAPD:
2303 bpf_error("LAPD link-layer type filtering not implemented");
2304 }
2305
2306 /*
2307 * All the types that have no encapsulation should either be
2308 * handled as DLT_SLIP, DLT_SLIP_BSDOS, and DLT_RAW are, if
2309 * all packets are IP packets, or should be handled in some
2310 * special case, if none of them are (if some are and some
2311 * aren't, the lack of encapsulation is a problem, as we'd
2312 * have to find some other way of determining the packet type).
2313 *
2314 * Therefore, if "off_linktype" is -1, there's an error.
2315 */
2316 if (off_linktype == (u_int)-1)
2317 abort();
2318
2319 /*
2320 * Any type not handled above should always have an Ethernet
2321 * type at an offset of "off_linktype". (PPP is partially
2322 * handled above - the protocol type is mapped from the
2323 * Ethernet and LLC types we use internally to the corresponding
2324 * PPP type - but the PPP type is always specified by a value
2325 * at "off_linktype", so we don't have to do the code generation
2326 * above.)
2327 */
2328 return gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32)proto);
2329 }
2330
2331 /*
2332 * Check for an LLC SNAP packet with a given organization code and
2333 * protocol type; we check the entire contents of the 802.2 LLC and
2334 * snap headers, checking for DSAP and SSAP of SNAP and a control
2335 * field of 0x03 in the LLC header, and for the specified organization
2336 * code and protocol type in the SNAP header.
2337 */
2338 static struct block *
2339 gen_snap(orgcode, ptype, offset)
2340 bpf_u_int32 orgcode;
2341 bpf_u_int32 ptype;
2342 u_int offset;
2343 {
2344 u_char snapblock[8];
2345
2346 snapblock[0] = LLCSAP_SNAP; /* DSAP = SNAP */
2347 snapblock[1] = LLCSAP_SNAP; /* SSAP = SNAP */
2348 snapblock[2] = 0x03; /* control = UI */
2349 snapblock[3] = (orgcode >> 16); /* upper 8 bits of organization code */
2350 snapblock[4] = (orgcode >> 8); /* middle 8 bits of organization code */
2351 snapblock[5] = (orgcode >> 0); /* lower 8 bits of organization code */
2352 snapblock[6] = (ptype >> 8); /* upper 8 bits of protocol type */
2353 snapblock[7] = (ptype >> 0); /* lower 8 bits of protocol type */
2354 return gen_bcmp(OR_LINK, offset, 8, snapblock);
2355 }
2356
2357 /*
2358 * Generate code to match a particular packet type, for link-layer types
2359 * using 802.2 LLC headers.
2360 *
2361 * This is *NOT* used for Ethernet; "gen_ether_linktype()" is used
2362 * for that - it handles the D/I/X Ethernet vs. 802.3+802.2 issues.
2363 *
2364 * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
2365 * value, if <= ETHERMTU. We use that to determine whether to
2366 * match the DSAP or both DSAP and LSAP or to check the OUI and
2367 * protocol ID in a SNAP header.
2368 */
2369 static struct block *
2370 gen_llc_linktype(proto)
2371 int proto;
2372 {
2373 /*
2374 * XXX - handle token-ring variable-length header.
2375 */
2376 switch (proto) {
2377
2378 case LLCSAP_IP:
2379 case LLCSAP_ISONS:
2380 case LLCSAP_NETBEUI:
2381 /*
2382 * XXX - should we check both the DSAP and the
2383 * SSAP, like this, or should we check just the
2384 * DSAP, as we do for other types <= ETHERMTU
2385 * (i.e., other SAP values)?
2386 */
2387 return gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_u_int32)
2388 ((proto << 8) | proto));
2389
2390 case LLCSAP_IPX:
2391 /*
2392 * XXX - are there ever SNAP frames for IPX on
2393 * non-Ethernet 802.x networks?
2394 */
2395 return gen_cmp(OR_LINK, off_linktype, BPF_B,
2396 (bpf_int32)LLCSAP_IPX);
2397
2398 case ETHERTYPE_ATALK:
2399 /*
2400 * 802.2-encapsulated ETHERTYPE_ATALK packets are
2401 * SNAP packets with an organization code of
2402 * 0x080007 (Apple, for Appletalk) and a protocol
2403 * type of ETHERTYPE_ATALK (Appletalk).
2404 *
2405 * XXX - check for an organization code of
2406 * encapsulated Ethernet as well?
2407 */
2408 return gen_snap(0x080007, ETHERTYPE_ATALK, off_linktype);
2409
2410 default:
2411 /*
2412 * XXX - we don't have to check for IPX 802.3
2413 * here, but should we check for the IPX Ethertype?
2414 */
2415 if (proto <= ETHERMTU) {
2416 /*
2417 * This is an LLC SAP value, so check
2418 * the DSAP.
2419 */
2420 return gen_cmp(OR_LINK, off_linktype, BPF_B,
2421 (bpf_int32)proto);
2422 } else {
2423 /*
2424 * This is an Ethernet type; we assume that it's
2425 * unlikely that it'll appear in the right place
2426 * at random, and therefore check only the
2427 * location that would hold the Ethernet type
2428 * in a SNAP frame with an organization code of
2429 * 0x000000 (encapsulated Ethernet).
2430 *
2431 * XXX - if we were to check for the SNAP DSAP and
2432 * LSAP, as per XXX, and were also to check for an
2433 * organization code of 0x000000 (encapsulated
2434 * Ethernet), we'd do
2435 *
2436 * return gen_snap(0x000000, proto,
2437 * off_linktype);
2438 *
2439 * here; for now, we don't, as per the above.
2440 * I don't know whether it's worth the extra CPU
2441 * time to do the right check or not.
2442 */
2443 return gen_cmp(OR_LINK, off_linktype+6, BPF_H,
2444 (bpf_int32)proto);
2445 }
2446 }
2447 }
2448
2449 static struct block *
2450 gen_hostop(addr, mask, dir, proto, src_off, dst_off)
2451 bpf_u_int32 addr;
2452 bpf_u_int32 mask;
2453 int dir, proto;
2454 u_int src_off, dst_off;
2455 {
2456 struct block *b0, *b1;
2457 u_int offset;
2458
2459 switch (dir) {
2460
2461 case Q_SRC:
2462 offset = src_off;
2463 break;
2464
2465 case Q_DST:
2466 offset = dst_off;
2467 break;
2468
2469 case Q_AND:
2470 b0 = gen_hostop(addr, mask, Q_SRC, proto, src_off, dst_off);
2471 b1 = gen_hostop(addr, mask, Q_DST, proto, src_off, dst_off);
2472 gen_and(b0, b1);
2473 return b1;
2474
2475 case Q_OR:
2476 case Q_DEFAULT:
2477 b0 = gen_hostop(addr, mask, Q_SRC, proto, src_off, dst_off);
2478 b1 = gen_hostop(addr, mask, Q_DST, proto, src_off, dst_off);
2479 gen_or(b0, b1);
2480 return b1;
2481
2482 default:
2483 abort();
2484 }
2485 b0 = gen_linktype(proto);
2486 b1 = gen_mcmp(OR_NET, offset, BPF_W, (bpf_int32)addr, mask);
2487 gen_and(b0, b1);
2488 return b1;
2489 }
2490
2491 #ifdef INET6
2492 static struct block *
2493 gen_hostop6(addr, mask, dir, proto, src_off, dst_off)
2494 struct in6_addr *addr;
2495 struct in6_addr *mask;
2496 int dir, proto;
2497 u_int src_off, dst_off;
2498 {
2499 struct block *b0, *b1;
2500 u_int offset;
2501 u_int32_t *a, *m;
2502
2503 switch (dir) {
2504
2505 case Q_SRC:
2506 offset = src_off;
2507 break;
2508
2509 case Q_DST:
2510 offset = dst_off;
2511 break;
2512
2513 case Q_AND:
2514 b0 = gen_hostop6(addr, mask, Q_SRC, proto, src_off, dst_off);
2515 b1 = gen_hostop6(addr, mask, Q_DST, proto, src_off, dst_off);
2516 gen_and(b0, b1);
2517 return b1;
2518
2519 case Q_OR:
2520 case Q_DEFAULT:
2521 b0 = gen_hostop6(addr, mask, Q_SRC, proto, src_off, dst_off);
2522 b1 = gen_hostop6(addr, mask, Q_DST, proto, src_off, dst_off);
2523 gen_or(b0, b1);
2524 return b1;
2525
2526 default:
2527 abort();
2528 }
2529 /* this order is important */
2530 a = (u_int32_t *)addr;
2531 m = (u_int32_t *)mask;
2532 b1 = gen_mcmp(OR_NET, offset + 12, BPF_W, ntohl(a[3]), ntohl(m[3]));
2533 b0 = gen_mcmp(OR_NET, offset + 8, BPF_W, ntohl(a[2]), ntohl(m[2]));
2534 gen_and(b0, b1);
2535 b0 = gen_mcmp(OR_NET, offset + 4, BPF_W, ntohl(a[1]), ntohl(m[1]));
2536 gen_and(b0, b1);
2537 b0 = gen_mcmp(OR_NET, offset + 0, BPF_W, ntohl(a[0]), ntohl(m[0]));
2538 gen_and(b0, b1);
2539 b0 = gen_linktype(proto);
2540 gen_and(b0, b1);
2541 return b1;
2542 }
2543 #endif /*INET6*/
2544
2545 static struct block *
2546 gen_ehostop(eaddr, dir)
2547 register const u_char *eaddr;
2548 register int dir;
2549 {
2550 register struct block *b0, *b1;
2551
2552 switch (dir) {
2553 case Q_SRC:
2554 return gen_bcmp(OR_LINK, off_mac + 6, 6, eaddr);
2555
2556 case Q_DST:
2557 return gen_bcmp(OR_LINK, off_mac + 0, 6, eaddr);
2558
2559 case Q_AND:
2560 b0 = gen_ehostop(eaddr, Q_SRC);
2561 b1 = gen_ehostop(eaddr, Q_DST);
2562 gen_and(b0, b1);
2563 return b1;
2564
2565 case Q_DEFAULT:
2566 case Q_OR:
2567 b0 = gen_ehostop(eaddr, Q_SRC);
2568 b1 = gen_ehostop(eaddr, Q_DST);
2569 gen_or(b0, b1);
2570 return b1;
2571 }
2572 abort();
2573 /* NOTREACHED */
2574 }
2575
2576 /*
2577 * Like gen_ehostop, but for DLT_FDDI
2578 */
2579 static struct block *
2580 gen_fhostop(eaddr, dir)
2581 register const u_char *eaddr;
2582 register int dir;
2583 {
2584 struct block *b0, *b1;
2585
2586 switch (dir) {
2587 case Q_SRC:
2588 #ifdef PCAP_FDDIPAD
2589 return gen_bcmp(OR_LINK, 6 + 1 + pcap_fddipad, 6, eaddr);
2590 #else
2591 return gen_bcmp(OR_LINK, 6 + 1, 6, eaddr);
2592 #endif
2593
2594 case Q_DST:
2595 #ifdef PCAP_FDDIPAD
2596 return gen_bcmp(OR_LINK, 0 + 1 + pcap_fddipad, 6, eaddr);
2597 #else
2598 return gen_bcmp(OR_LINK, 0 + 1, 6, eaddr);
2599 #endif
2600
2601 case Q_AND:
2602 b0 = gen_fhostop(eaddr, Q_SRC);
2603 b1 = gen_fhostop(eaddr, Q_DST);
2604 gen_and(b0, b1);
2605 return b1;
2606
2607 case Q_DEFAULT:
2608 case Q_OR:
2609 b0 = gen_fhostop(eaddr, Q_SRC);
2610 b1 = gen_fhostop(eaddr, Q_DST);
2611 gen_or(b0, b1);
2612 return b1;
2613 }
2614 abort();
2615 /* NOTREACHED */
2616 }
2617
2618 /*
2619 * Like gen_ehostop, but for DLT_IEEE802 (Token Ring)
2620 */
2621 static struct block *
2622 gen_thostop(eaddr, dir)
2623 register const u_char *eaddr;
2624 register int dir;
2625 {
2626 register struct block *b0, *b1;
2627
2628 switch (dir) {
2629 case Q_SRC:
2630 return gen_bcmp(OR_LINK, 8, 6, eaddr);
2631
2632 case Q_DST:
2633 return gen_bcmp(OR_LINK, 2, 6, eaddr);
2634
2635 case Q_AND:
2636 b0 = gen_thostop(eaddr, Q_SRC);
2637 b1 = gen_thostop(eaddr, Q_DST);
2638 gen_and(b0, b1);
2639 return b1;
2640
2641 case Q_DEFAULT:
2642 case Q_OR:
2643 b0 = gen_thostop(eaddr, Q_SRC);
2644 b1 = gen_thostop(eaddr, Q_DST);
2645 gen_or(b0, b1);
2646 return b1;
2647 }
2648 abort();
2649 /* NOTREACHED */
2650 }
2651
2652 /*
2653 * Like gen_ehostop, but for DLT_IEEE802_11 (802.11 wireless LAN)
2654 */
2655 static struct block *
2656 gen_wlanhostop(eaddr, dir)
2657 register const u_char *eaddr;
2658 register int dir;
2659 {
2660 register struct block *b0, *b1, *b2;
2661 register struct slist *s;
2662
2663 switch (dir) {
2664 case Q_SRC:
2665 /*
2666 * Oh, yuk.
2667 *
2668 * For control frames, there is no SA.
2669 *
2670 * For management frames, SA is at an
2671 * offset of 10 from the beginning of
2672 * the packet.
2673 *
2674 * For data frames, SA is at an offset
2675 * of 10 from the beginning of the packet
2676 * if From DS is clear, at an offset of
2677 * 16 from the beginning of the packet
2678 * if From DS is set and To DS is clear,
2679 * and an offset of 24 from the beginning
2680 * of the packet if From DS is set and To DS
2681 * is set.
2682 */
2683
2684 /*
2685 * Generate the tests to be done for data frames
2686 * with From DS set.
2687 *
2688 * First, check for To DS set, i.e. check "link[1] & 0x01".
2689 */
2690 s = gen_load_a(OR_LINK, 1, BPF_B);
2691 b1 = new_block(JMP(BPF_JSET));
2692 b1->s.k = 0x01; /* To DS */
2693 b1->stmts = s;
2694
2695 /*
2696 * If To DS is set, the SA is at 24.
2697 */
2698 b0 = gen_bcmp(OR_LINK, 24, 6, eaddr);
2699 gen_and(b1, b0);
2700
2701 /*
2702 * Now, check for To DS not set, i.e. check
2703 * "!(link[1] & 0x01)".
2704 */
2705 s = gen_load_a(OR_LINK, 1, BPF_B);
2706 b2 = new_block(JMP(BPF_JSET));
2707 b2->s.k = 0x01; /* To DS */
2708 b2->stmts = s;
2709 gen_not(b2);
2710
2711 /*
2712 * If To DS is not set, the SA is at 16.
2713 */
2714 b1 = gen_bcmp(OR_LINK, 16, 6, eaddr);
2715 gen_and(b2, b1);
2716
2717 /*
2718 * Now OR together the last two checks. That gives
2719 * the complete set of checks for data frames with
2720 * From DS set.
2721 */
2722 gen_or(b1, b0);
2723
2724 /*
2725 * Now check for From DS being set, and AND that with
2726 * the ORed-together checks.
2727 */
2728 s = gen_load_a(OR_LINK, 1, BPF_B);
2729 b1 = new_block(JMP(BPF_JSET));
2730 b1->s.k = 0x02; /* From DS */
2731 b1->stmts = s;
2732 gen_and(b1, b0);
2733
2734 /*
2735 * Now check for data frames with From DS not set.
2736 */
2737 s = gen_load_a(OR_LINK, 1, BPF_B);
2738 b2 = new_block(JMP(BPF_JSET));
2739 b2->s.k = 0x02; /* From DS */
2740 b2->stmts = s;
2741 gen_not(b2);
2742
2743 /*
2744 * If From DS isn't set, the SA is at 10.
2745 */
2746 b1 = gen_bcmp(OR_LINK, 10, 6, eaddr);
2747 gen_and(b2, b1);
2748
2749 /*
2750 * Now OR together the checks for data frames with
2751 * From DS not set and for data frames with From DS
2752 * set; that gives the checks done for data frames.
2753 */
2754 gen_or(b1, b0);
2755
2756 /*
2757 * Now check for a data frame.
2758 * I.e, check "link[0] & 0x08".
2759 */
2760 gen_load_a(OR_LINK, 0, BPF_B);
2761 b1 = new_block(JMP(BPF_JSET));
2762 b1->s.k = 0x08;
2763 b1->stmts = s;
2764
2765 /*
2766 * AND that with the checks done for data frames.
2767 */
2768 gen_and(b1, b0);
2769
2770 /*
2771 * If the high-order bit of the type value is 0, this
2772 * is a management frame.
2773 * I.e, check "!(link[0] & 0x08)".
2774 */
2775 s = gen_load_a(OR_LINK, 0, BPF_B);
2776 b2 = new_block(JMP(BPF_JSET));
2777 b2->s.k = 0x08;
2778 b2->stmts = s;
2779 gen_not(b2);
2780
2781 /*
2782 * For management frames, the SA is at 10.
2783 */
2784 b1 = gen_bcmp(OR_LINK, 10, 6, eaddr);
2785 gen_and(b2, b1);
2786
2787 /*
2788 * OR that with the checks done for data frames.
2789 * That gives the checks done for management and
2790 * data frames.
2791 */
2792 gen_or(b1, b0);
2793
2794 /*
2795 * If the low-order bit of the type value is 1,
2796 * this is either a control frame or a frame
2797 * with a reserved type, and thus not a
2798 * frame with an SA.
2799 *
2800 * I.e., check "!(link[0] & 0x04)".
2801 */
2802 s = gen_load_a(OR_LINK, 0, BPF_B);
2803 b1 = new_block(JMP(BPF_JSET));
2804 b1->s.k = 0x04;
2805 b1->stmts = s;
2806 gen_not(b1);
2807
2808 /*
2809 * AND that with the checks for data and management
2810 * frames.
2811 */
2812 gen_and(b1, b0);
2813 return b0;
2814
2815 case Q_DST:
2816 /*
2817 * Oh, yuk.
2818 *
2819 * For control frames, there is no DA.
2820 *
2821 * For management frames, DA is at an
2822 * offset of 4 from the beginning of
2823 * the packet.
2824 *
2825 * For data frames, DA is at an offset
2826 * of 4 from the beginning of the packet
2827 * if To DS is clear and at an offset of
2828 * 16 from the beginning of the packet
2829 * if To DS is set.
2830 */
2831
2832 /*
2833 * Generate the tests to be done for data frames.
2834 *
2835 * First, check for To DS set, i.e. "link[1] & 0x01".
2836 */
2837 s = gen_load_a(OR_LINK, 1, BPF_B);
2838 b1 = new_block(JMP(BPF_JSET));
2839 b1->s.k = 0x01; /* To DS */
2840 b1->stmts = s;
2841
2842 /*
2843 * If To DS is set, the DA is at 16.
2844 */
2845 b0 = gen_bcmp(OR_LINK, 16, 6, eaddr);
2846 gen_and(b1, b0);
2847
2848 /*
2849 * Now, check for To DS not set, i.e. check
2850 * "!(link[1] & 0x01)".
2851 */
2852 s = gen_load_a(OR_LINK, 1, BPF_B);
2853 b2 = new_block(JMP(BPF_JSET));
2854 b2->s.k = 0x01; /* To DS */
2855 b2->stmts = s;
2856 gen_not(b2);
2857
2858 /*
2859 * If To DS is not set, the DA is at 4.
2860 */
2861 b1 = gen_bcmp(OR_LINK, 4, 6, eaddr);
2862 gen_and(b2, b1);
2863
2864 /*
2865 * Now OR together the last two checks. That gives
2866 * the complete set of checks for data frames.
2867 */
2868 gen_or(b1, b0);
2869
2870 /*
2871 * Now check for a data frame.
2872 * I.e, check "link[0] & 0x08".
2873 */
2874 s = gen_load_a(OR_LINK, 0, BPF_B);
2875 b1 = new_block(JMP(BPF_JSET));
2876 b1->s.k = 0x08;
2877 b1->stmts = s;
2878
2879 /*
2880 * AND that with the checks done for data frames.
2881 */
2882 gen_and(b1, b0);
2883
2884 /*
2885 * If the high-order bit of the type value is 0, this
2886 * is a management frame.
2887 * I.e, check "!(link[0] & 0x08)".
2888 */
2889 s = gen_load_a(OR_LINK, 0, BPF_B);
2890 b2 = new_block(JMP(BPF_JSET));
2891 b2->s.k = 0x08;
2892 b2->stmts = s;
2893 gen_not(b2);
2894
2895 /*
2896 * For management frames, the DA is at 4.
2897 */
2898 b1 = gen_bcmp(OR_LINK, 4, 6, eaddr);
2899 gen_and(b2, b1);
2900
2901 /*
2902 * OR that with the checks done for data frames.
2903 * That gives the checks done for management and
2904 * data frames.
2905 */
2906 gen_or(b1, b0);
2907
2908 /*
2909 * If the low-order bit of the type value is 1,
2910 * this is either a control frame or a frame
2911 * with a reserved type, and thus not a
2912 * frame with an SA.
2913 *
2914 * I.e., check "!(link[0] & 0x04)".
2915 */
2916 s = gen_load_a(OR_LINK, 0, BPF_B);
2917 b1 = new_block(JMP(BPF_JSET));
2918 b1->s.k = 0x04;
2919 b1->stmts = s;
2920 gen_not(b1);
2921
2922 /*
2923 * AND that with the checks for data and management
2924 * frames.
2925 */
2926 gen_and(b1, b0);
2927 return b0;
2928
2929 case Q_AND:
2930 b0 = gen_wlanhostop(eaddr, Q_SRC);
2931 b1 = gen_wlanhostop(eaddr, Q_DST);
2932 gen_and(b0, b1);
2933 return b1;
2934
2935 case Q_DEFAULT:
2936 case Q_OR:
2937 b0 = gen_wlanhostop(eaddr, Q_SRC);
2938 b1 = gen_wlanhostop(eaddr, Q_DST);
2939 gen_or(b0, b1);
2940 return b1;
2941 }
2942 abort();
2943 /* NOTREACHED */
2944 }
2945
2946 /*
2947 * Like gen_ehostop, but for RFC 2625 IP-over-Fibre-Channel.
2948 * (We assume that the addresses are IEEE 48-bit MAC addresses,
2949 * as the RFC states.)
2950 */
2951 static struct block *
2952 gen_ipfchostop(eaddr, dir)
2953 register const u_char *eaddr;
2954 register int dir;
2955 {
2956 register struct block *b0, *b1;
2957
2958 switch (dir) {
2959 case Q_SRC:
2960 return gen_bcmp(OR_LINK, 10, 6, eaddr);
2961
2962 case Q_DST:
2963 return gen_bcmp(OR_LINK, 2, 6, eaddr);
2964
2965 case Q_AND:
2966 b0 = gen_ipfchostop(eaddr, Q_SRC);
2967 b1 = gen_ipfchostop(eaddr, Q_DST);
2968 gen_and(b0, b1);
2969 return b1;
2970
2971 case Q_DEFAULT:
2972 case Q_OR:
2973 b0 = gen_ipfchostop(eaddr, Q_SRC);
2974 b1 = gen_ipfchostop(eaddr, Q_DST);
2975 gen_or(b0, b1);
2976 return b1;
2977 }
2978 abort();
2979 /* NOTREACHED */
2980 }
2981
2982 /*
2983 * This is quite tricky because there may be pad bytes in front of the
2984 * DECNET header, and then there are two possible data packet formats that
2985 * carry both src and dst addresses, plus 5 packet types in a format that
2986 * carries only the src node, plus 2 types that use a different format and
2987 * also carry just the src node.
2988 *
2989 * Yuck.
2990 *
2991 * Instead of doing those all right, we just look for data packets with
2992 * 0 or 1 bytes of padding. If you want to look at other packets, that
2993 * will require a lot more hacking.
2994 *
2995 * To add support for filtering on DECNET "areas" (network numbers)
2996 * one would want to add a "mask" argument to this routine. That would
2997 * make the filter even more inefficient, although one could be clever
2998 * and not generate masking instructions if the mask is 0xFFFF.
2999 */
3000 static struct block *
3001 gen_dnhostop(addr, dir)
3002 bpf_u_int32 addr;
3003 int dir;
3004 {
3005 struct block *b0, *b1, *b2, *tmp;
3006 u_int offset_lh; /* offset if long header is received */
3007 u_int offset_sh; /* offset if short header is received */
3008
3009 switch (dir) {
3010
3011 case Q_DST:
3012 offset_sh = 1; /* follows flags */
3013 offset_lh = 7; /* flgs,darea,dsubarea,HIORD */
3014 break;
3015
3016 case Q_SRC:
3017 offset_sh = 3; /* follows flags, dstnode */
3018 offset_lh = 15; /* flgs,darea,dsubarea,did,sarea,ssub,HIORD */
3019 break;
3020
3021 case Q_AND:
3022 /* Inefficient because we do our Calvinball dance twice */
3023 b0 = gen_dnhostop(addr, Q_SRC);
3024 b1 = gen_dnhostop(addr, Q_DST);
3025 gen_and(b0, b1);
3026 return b1;
3027
3028 case Q_OR:
3029 case Q_DEFAULT:
3030 /* Inefficient because we do our Calvinball dance twice */
3031 b0 = gen_dnhostop(addr, Q_SRC);
3032 b1 = gen_dnhostop(addr, Q_DST);
3033 gen_or(b0, b1);
3034 return b1;
3035
3036 case Q_ISO:
3037 bpf_error("ISO host filtering not implemented");
3038
3039 default:
3040 abort();
3041 }
3042 b0 = gen_linktype(ETHERTYPE_DN);
3043 /* Check for pad = 1, long header case */
3044 tmp = gen_mcmp(OR_NET, 2, BPF_H,
3045 (bpf_int32)ntohs(0x0681), (bpf_int32)ntohs(0x07FF));
3046 b1 = gen_cmp(OR_NET, 2 + 1 + offset_lh,
3047 BPF_H, (bpf_int32)ntohs(addr));
3048 gen_and(tmp, b1);
3049 /* Check for pad = 0, long header case */
3050 tmp = gen_mcmp(OR_NET, 2, BPF_B, (bpf_int32)0x06, (bpf_int32)0x7);
3051 b2 = gen_cmp(OR_NET, 2 + offset_lh, BPF_H, (bpf_int32)ntohs(addr));
3052 gen_and(tmp, b2);
3053 gen_or(b2, b1);
3054 /* Check for pad = 1, short header case */
3055 tmp = gen_mcmp(OR_NET, 2, BPF_H,
3056 (bpf_int32)ntohs(0x0281), (bpf_int32)ntohs(0x07FF));
3057 b2 = gen_cmp(OR_NET, 2 + 1 + offset_sh, BPF_H, (bpf_int32)ntohs(addr));
3058 gen_and(tmp, b2);
3059 gen_or(b2, b1);
3060 /* Check for pad = 0, short header case */
3061 tmp = gen_mcmp(OR_NET, 2, BPF_B, (bpf_int32)0x02, (bpf_int32)0x7);
3062 b2 = gen_cmp(OR_NET, 2 + offset_sh, BPF_H, (bpf_int32)ntohs(addr));
3063 gen_and(tmp, b2);
3064 gen_or(b2, b1);
3065
3066 /* Combine with test for linktype */
3067 gen_and(b0, b1);
3068 return b1;
3069 }
3070
3071 /*
3072 * Generate a check for IPv4 or IPv6 for MPLS-encapsulated packets;
3073 * test the bottom-of-stack bit, and then check the version number
3074 * field in the IP header.
3075 */
3076 static struct block *
3077 gen_mpls_linktype(proto)
3078 int proto;
3079 {
3080 struct block *b0, *b1;
3081
3082 switch (proto) {
3083
3084 case Q_IP:
3085 /* match the bottom-of-stack bit */
3086 b0 = gen_mcmp(OR_NET, -2, BPF_B, 0x01, 0x01);
3087 /* match the IPv4 version number */
3088 b1 = gen_mcmp(OR_NET, 0, BPF_B, 0x40, 0xf0);
3089 gen_and(b0, b1);
3090 return b1;
3091
3092 case Q_IPV6:
3093 /* match the bottom-of-stack bit */
3094 b0 = gen_mcmp(OR_NET, -2, BPF_B, 0x01, 0x01);
3095 /* match the IPv4 version number */
3096 b1 = gen_mcmp(OR_NET, 0, BPF_B, 0x60, 0xf0);
3097 gen_and(b0, b1);
3098 return b1;
3099
3100 default:
3101 abort();
3102 }
3103 }
3104
3105 static struct block *
3106 gen_host(addr, mask, proto, dir)
3107 bpf_u_int32 addr;
3108 bpf_u_int32 mask;
3109 int proto;
3110 int dir;
3111 {
3112 struct block *b0, *b1;
3113
3114 switch (proto) {
3115
3116 case Q_DEFAULT:
3117 b0 = gen_host(addr, mask, Q_IP, dir);
3118 /*
3119 * Only check for non-IPv4 addresses if we're not
3120 * checking MPLS-encapsulated packets.
3121 */
3122 if (label_stack_depth == 0) {
3123 b1 = gen_host(addr, mask, Q_ARP, dir);
3124 gen_or(b0, b1);
3125 b0 = gen_host(addr, mask, Q_RARP, dir);
3126 gen_or(b1, b0);
3127 }
3128 return b0;
3129
3130 case Q_IP:
3131 return gen_hostop(addr, mask, dir, ETHERTYPE_IP, 12, 16);
3132
3133 case Q_RARP:
3134 return gen_hostop(addr, mask, dir, ETHERTYPE_REVARP, 14, 24);
3135
3136 case Q_ARP:
3137 return gen_hostop(addr, mask, dir, ETHERTYPE_ARP, 14, 24);
3138
3139 case Q_TCP:
3140 bpf_error("'tcp' modifier applied to host");
3141
3142 case Q_SCTP:
3143 bpf_error("'sctp' modifier applied to host");
3144
3145 case Q_UDP:
3146 bpf_error("'udp' modifier applied to host");
3147
3148 case Q_ICMP:
3149 bpf_error("'icmp' modifier applied to host");
3150
3151 case Q_IGMP:
3152 bpf_error("'igmp' modifier applied to host");
3153
3154 case Q_IGRP:
3155 bpf_error("'igrp' modifier applied to host");
3156
3157 case Q_PIM:
3158 bpf_error("'pim' modifier applied to host");
3159
3160 case Q_VRRP:
3161 bpf_error("'vrrp' modifier applied to host");
3162
3163 case Q_ATALK:
3164 bpf_error("ATALK host filtering not implemented");
3165
3166 case Q_AARP:
3167 bpf_error("AARP host filtering not implemented");
3168
3169 case Q_DECNET:
3170 return gen_dnhostop(addr, dir);
3171
3172 case Q_SCA:
3173 bpf_error("SCA host filtering not implemented");
3174
3175 case Q_LAT:
3176 bpf_error("LAT host filtering not implemented");
3177
3178 case Q_MOPDL:
3179 bpf_error("MOPDL host filtering not implemented");
3180
3181 case Q_MOPRC:
3182 bpf_error("MOPRC host filtering not implemented");
3183
3184 #ifdef INET6
3185 case Q_IPV6:
3186 bpf_error("'ip6' modifier applied to ip host");
3187
3188 case Q_ICMPV6:
3189 bpf_error("'icmp6' modifier applied to host");
3190 #endif /* INET6 */
3191
3192 case Q_AH:
3193 bpf_error("'ah' modifier applied to host");
3194
3195 case Q_ESP:
3196 bpf_error("'esp' modifier applied to host");
3197
3198 case Q_ISO:
3199 bpf_error("ISO host filtering not implemented");
3200
3201 case Q_ESIS:
3202 bpf_error("'esis' modifier applied to host");
3203
3204 case Q_ISIS:
3205 bpf_error("'isis' modifier applied to host");
3206
3207 case Q_CLNP:
3208 bpf_error("'clnp' modifier applied to host");
3209
3210 case Q_STP:
3211 bpf_error("'stp' modifier applied to host");
3212
3213 case Q_IPX:
3214 bpf_error("IPX host filtering not implemented");
3215
3216 case Q_NETBEUI:
3217 bpf_error("'netbeui' modifier applied to host");
3218
3219 case Q_RADIO:
3220 bpf_error("'radio' modifier applied to host");
3221
3222 default:
3223 abort();
3224 }
3225 /* NOTREACHED */
3226 }
3227
3228 #ifdef INET6
3229 static struct block *
3230 gen_host6(addr, mask, proto, dir)
3231 struct in6_addr *addr;
3232 struct in6_addr *mask;
3233 int proto;
3234 int dir;
3235 {
3236 switch (proto) {
3237
3238 case Q_DEFAULT:
3239 return gen_host6(addr, mask, Q_IPV6, dir);
3240
3241 case Q_IP:
3242 bpf_error("'ip' modifier applied to ip6 host");
3243
3244 case Q_RARP:
3245 bpf_error("'rarp' modifier applied to ip6 host");
3246
3247 case Q_ARP:
3248 bpf_error("'arp' modifier applied to ip6 host");
3249
3250 case Q_SCTP:
3251 bpf_error("'sctp' modifier applied to host");
3252
3253 case Q_TCP:
3254 bpf_error("'tcp' modifier applied to host");
3255
3256 case Q_UDP:
3257 bpf_error("'udp' modifier applied to host");
3258
3259 case Q_ICMP:
3260 bpf_error("'icmp' modifier applied to host");
3261
3262 case Q_IGMP:
3263 bpf_error("'igmp' modifier applied to host");
3264
3265 case Q_IGRP:
3266 bpf_error("'igrp' modifier applied to host");
3267
3268 case Q_PIM:
3269 bpf_error("'pim' modifier applied to host");
3270
3271 case Q_VRRP:
3272 bpf_error("'vrrp' modifier applied to host");
3273
3274 case Q_ATALK:
3275 bpf_error("ATALK host filtering not implemented");
3276
3277 case Q_AARP:
3278 bpf_error("AARP host filtering not implemented");
3279
3280 case Q_DECNET:
3281 bpf_error("'decnet' modifier applied to ip6 host");
3282
3283 case Q_SCA:
3284 bpf_error("SCA host filtering not implemented");
3285
3286 case Q_LAT:
3287 bpf_error("LAT host filtering not implemented");
3288
3289 case Q_MOPDL:
3290 bpf_error("MOPDL host filtering not implemented");
3291
3292 case Q_MOPRC:
3293 bpf_error("MOPRC host filtering not implemented");
3294
3295 case Q_IPV6:
3296 return gen_hostop6(addr, mask, dir, ETHERTYPE_IPV6, 8, 24);
3297
3298 case Q_ICMPV6:
3299 bpf_error("'icmp6' modifier applied to host");
3300
3301 case Q_AH:
3302 bpf_error("'ah' modifier applied to host");
3303
3304 case Q_ESP:
3305 bpf_error("'esp' modifier applied to host");
3306
3307 case Q_ISO:
3308 bpf_error("ISO host filtering not implemented");
3309
3310 case Q_ESIS:
3311 bpf_error("'esis' modifier applied to host");
3312
3313 case Q_ISIS:
3314 bpf_error("'isis' modifier applied to host");
3315
3316 case Q_CLNP:
3317 bpf_error("'clnp' modifier applied to host");
3318
3319 case Q_STP:
3320 bpf_error("'stp' modifier applied to host");
3321
3322 case Q_IPX:
3323 bpf_error("IPX host filtering not implemented");
3324
3325 case Q_NETBEUI:
3326 bpf_error("'netbeui' modifier applied to host");
3327
3328 case Q_RADIO:
3329 bpf_error("'radio' modifier applied to host");
3330
3331 default:
3332 abort();
3333 }
3334 /* NOTREACHED */
3335 }
3336 #endif /*INET6*/
3337
3338 #ifndef INET6
3339 static struct block *
3340 gen_gateway(eaddr, alist, proto, dir)
3341 const u_char *eaddr;
3342 bpf_u_int32 **alist;
3343 int proto;
3344 int dir;
3345 {
3346 struct block *b0, *b1, *tmp;
3347
3348 if (dir != 0)
3349 bpf_error("direction applied to 'gateway'");
3350
3351 switch (proto) {
3352 case Q_DEFAULT:
3353 case Q_IP:
3354 case Q_ARP:
3355 case Q_RARP:
3356 if (linktype == DLT_EN10MB)
3357 b0 = gen_ehostop(eaddr, Q_OR);
3358 else if (linktype == DLT_FDDI)
3359 b0 = gen_fhostop(eaddr, Q_OR);
3360 else if (linktype == DLT_IEEE802)
3361 b0 = gen_thostop(eaddr, Q_OR);
3362 else if (linktype == DLT_IEEE802_11 ||
3363 linktype == DLT_IEEE802_11_RADIO_AVS ||
3364 linktype == DLT_IEEE802_11_RADIO ||
3365 linktype == DLT_PRISM_HEADER)
3366 b0 = gen_wlanhostop(eaddr, Q_OR);
3367 else if (linktype == DLT_SUNATM && is_lane) {
3368 /*
3369 * Check that the packet doesn't begin with an
3370 * LE Control marker. (We've already generated
3371 * a test for LANE.)
3372 */
3373 b1 = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS, BPF_H,
3374 0xFF00);
3375 gen_not(b1);
3376
3377 /*
3378 * Now check the MAC address.
3379 */
3380 b0 = gen_ehostop(eaddr, Q_OR);
3381 gen_and(b1, b0);
3382 } else if (linktype == DLT_IP_OVER_FC)
3383 b0 = gen_ipfchostop(eaddr, Q_OR);
3384 else
3385 bpf_error(
3386 "'gateway' supported only on ethernet/FDDI/token ring/802.11/Fibre Channel");
3387
3388 b1 = gen_host(**alist++, 0xffffffff, proto, Q_OR);
3389 while (*alist) {
3390 tmp = gen_host(**alist++, 0xffffffff, proto, Q_OR);
3391 gen_or(b1, tmp);
3392 b1 = tmp;
3393 }
3394 gen_not(b1);
3395 gen_and(b0, b1);
3396 return b1;
3397 }
3398 bpf_error("illegal modifier of 'gateway'");
3399 /* NOTREACHED */
3400 }
3401 #endif
3402
3403 struct block *
3404 gen_proto_abbrev(proto)
3405 int proto;
3406 {
3407 struct block *b0;
3408 struct block *b1;
3409
3410 switch (proto) {
3411
3412 case Q_SCTP:
3413 b1 = gen_proto(IPPROTO_SCTP, Q_IP, Q_DEFAULT);
3414 #ifdef INET6
3415 b0 = gen_proto(IPPROTO_SCTP, Q_IPV6, Q_DEFAULT);
3416 gen_or(b0, b1);
3417 #endif
3418 break;
3419
3420 case Q_TCP:
3421 b1 = gen_proto(IPPROTO_TCP, Q_IP, Q_DEFAULT);
3422 #ifdef INET6
3423 b0 = gen_proto(IPPROTO_TCP, Q_IPV6, Q_DEFAULT);
3424 gen_or(b0, b1);
3425 #endif
3426 break;
3427
3428 case Q_UDP:
3429 b1 = gen_proto(IPPROTO_UDP, Q_IP, Q_DEFAULT);
3430 #ifdef INET6
3431 b0 = gen_proto(IPPROTO_UDP, Q_IPV6, Q_DEFAULT);
3432 gen_or(b0, b1);
3433 #endif
3434 break;
3435
3436 case Q_ICMP:
3437 b1 = gen_proto(IPPROTO_ICMP, Q_IP, Q_DEFAULT);
3438 break;
3439
3440 #ifndef IPPROTO_IGMP
3441 #define IPPROTO_IGMP 2
3442 #endif
3443
3444 case Q_IGMP:
3445 b1 = gen_proto(IPPROTO_IGMP, Q_IP, Q_DEFAULT);
3446 break;
3447
3448 #ifndef IPPROTO_IGRP
3449 #define IPPROTO_IGRP 9
3450 #endif
3451 case Q_IGRP:
3452 b1 = gen_proto(IPPROTO_IGRP, Q_IP, Q_DEFAULT);
3453 break;
3454
3455 #ifndef IPPROTO_PIM
3456 #define IPPROTO_PIM 103
3457 #endif
3458
3459 case Q_PIM:
3460 b1 = gen_proto(IPPROTO_PIM, Q_IP, Q_DEFAULT);
3461 #ifdef INET6
3462 b0 = gen_proto(IPPROTO_PIM, Q_IPV6, Q_DEFAULT);
3463 gen_or(b0, b1);
3464 #endif
3465 break;
3466
3467 #ifndef IPPROTO_VRRP
3468 #define IPPROTO_VRRP 112
3469 #endif
3470
3471 case Q_VRRP:
3472 b1 = gen_proto(IPPROTO_VRRP, Q_IP, Q_DEFAULT);
3473 break;
3474
3475 case Q_IP:
3476 b1 = gen_linktype(ETHERTYPE_IP);
3477 break;
3478
3479 case Q_ARP:
3480 b1 = gen_linktype(ETHERTYPE_ARP);
3481 break;
3482
3483 case Q_RARP:
3484 b1 = gen_linktype(ETHERTYPE_REVARP);
3485 break;
3486
3487 case Q_LINK:
3488 bpf_error("link layer applied in wrong context");
3489
3490 case Q_ATALK:
3491 b1 = gen_linktype(ETHERTYPE_ATALK);
3492 break;
3493
3494 case Q_AARP:
3495 b1 = gen_linktype(ETHERTYPE_AARP);
3496 break;
3497
3498 case Q_DECNET:
3499 b1 = gen_linktype(ETHERTYPE_DN);
3500 break;
3501
3502 case Q_SCA:
3503 b1 = gen_linktype(ETHERTYPE_SCA);
3504 break;
3505
3506 case Q_LAT:
3507 b1 = gen_linktype(ETHERTYPE_LAT);
3508 break;
3509
3510 case Q_MOPDL:
3511 b1 = gen_linktype(ETHERTYPE_MOPDL);
3512 break;
3513
3514 case Q_MOPRC:
3515 b1 = gen_linktype(ETHERTYPE_MOPRC);
3516 break;
3517
3518 #ifdef INET6
3519 case Q_IPV6:
3520 b1 = gen_linktype(ETHERTYPE_IPV6);
3521 break;
3522
3523 #ifndef IPPROTO_ICMPV6
3524 #define IPPROTO_ICMPV6 58
3525 #endif
3526 case Q_ICMPV6:
3527 b1 = gen_proto(IPPROTO_ICMPV6, Q_IPV6, Q_DEFAULT);
3528 break;
3529 #endif /* INET6 */
3530
3531 #ifndef IPPROTO_AH
3532 #define IPPROTO_AH 51
3533 #endif
3534 case Q_AH:
3535 b1 = gen_proto(IPPROTO_AH, Q_IP, Q_DEFAULT);
3536 #ifdef INET6
3537 b0 = gen_proto(IPPROTO_AH, Q_IPV6, Q_DEFAULT);
3538 gen_or(b0, b1);
3539 #endif
3540 break;
3541
3542 #ifndef IPPROTO_ESP
3543 #define IPPROTO_ESP 50
3544 #endif
3545 case Q_ESP:
3546 b1 = gen_proto(IPPROTO_ESP, Q_IP, Q_DEFAULT);
3547 #ifdef INET6
3548 b0 = gen_proto(IPPROTO_ESP, Q_IPV6, Q_DEFAULT);
3549 gen_or(b0, b1);
3550 #endif
3551 break;
3552
3553 case Q_ISO:
3554 b1 = gen_linktype(LLCSAP_ISONS);
3555 break;
3556
3557 case Q_ESIS:
3558 b1 = gen_proto(ISO9542_ESIS, Q_ISO, Q_DEFAULT);
3559 break;
3560
3561 case Q_ISIS:
3562 b1 = gen_proto(ISO10589_ISIS, Q_ISO, Q_DEFAULT);
3563 break;
3564
3565 case Q_ISIS_L1: /* all IS-IS Level1 PDU-Types */
3566 b0 = gen_proto(ISIS_L1_LAN_IIH, Q_ISIS, Q_DEFAULT);
3567 b1 = gen_proto(ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); /* FIXME extract the circuit-type bits */
3568 gen_or(b0, b1);
3569 b0 = gen_proto(ISIS_L1_LSP, Q_ISIS, Q_DEFAULT);
3570 gen_or(b0, b1);
3571 b0 = gen_proto(ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
3572 gen_or(b0, b1);
3573 b0 = gen_proto(ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
3574 gen_or(b0, b1);
3575 break;
3576
3577 case Q_ISIS_L2: /* all IS-IS Level2 PDU-Types */
3578 b0 = gen_proto(ISIS_L2_LAN_IIH, Q_ISIS, Q_DEFAULT);
3579 b1 = gen_proto(ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); /* FIXME extract the circuit-type bits */
3580 gen_or(b0, b1);
3581 b0 = gen_proto(ISIS_L2_LSP, Q_ISIS, Q_DEFAULT);
3582 gen_or(b0, b1);
3583 b0 = gen_proto(ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
3584 gen_or(b0, b1);
3585 b0 = gen_proto(ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
3586 gen_or(b0, b1);
3587 break;
3588
3589 case Q_ISIS_IIH: /* all IS-IS Hello PDU-Types */
3590 b0 = gen_proto(ISIS_L1_LAN_IIH, Q_ISIS, Q_DEFAULT);
3591 b1 = gen_proto(ISIS_L2_LAN_IIH, Q_ISIS, Q_DEFAULT);
3592 gen_or(b0, b1);
3593 b0 = gen_proto(ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT);
3594 gen_or(b0, b1);
3595 break;
3596
3597 case Q_ISIS_LSP:
3598 b0 = gen_proto(ISIS_L1_LSP, Q_ISIS, Q_DEFAULT);
3599 b1 = gen_proto(ISIS_L2_LSP, Q_ISIS, Q_DEFAULT);
3600 gen_or(b0, b1);
3601 break;
3602
3603 case Q_ISIS_SNP:
3604 b0 = gen_proto(ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
3605 b1 = gen_proto(ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
3606 gen_or(b0, b1);
3607 b0 = gen_proto(ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
3608 gen_or(b0, b1);
3609 b0 = gen_proto(ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
3610 gen_or(b0, b1);
3611 break;
3612
3613 case Q_ISIS_CSNP:
3614 b0 = gen_proto(ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
3615 b1 = gen_proto(ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
3616 gen_or(b0, b1);
3617 break;
3618
3619 case Q_ISIS_PSNP:
3620 b0 = gen_proto(ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
3621 b1 = gen_proto(ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
3622 gen_or(b0, b1);
3623 break;
3624
3625 case Q_CLNP:
3626 b1 = gen_proto(ISO8473_CLNP, Q_ISO, Q_DEFAULT);
3627 break;
3628
3629 case Q_STP:
3630 b1 = gen_linktype(LLCSAP_8021D);
3631 break;
3632
3633 case Q_IPX:
3634 b1 = gen_linktype(LLCSAP_IPX);
3635 break;
3636
3637 case Q_NETBEUI:
3638 b1 = gen_linktype(LLCSAP_NETBEUI);
3639 break;
3640
3641 case Q_RADIO:
3642 bpf_error("'radio' is not a valid protocol type");
3643
3644 default:
3645 abort();
3646 }
3647 return b1;
3648 }
3649
3650 static struct block *
3651 gen_ipfrag()
3652 {
3653 struct slist *s;
3654 struct block *b;
3655
3656 /* not ip frag */
3657 s = gen_load_a(OR_NET, 6, BPF_H);
3658 b = new_block(JMP(BPF_JSET));
3659 b->s.k = 0x1fff;
3660 b->stmts = s;
3661 gen_not(b);
3662
3663 return b;
3664 }
3665
3666 /*
3667 * Generate a comparison to a port value in the transport-layer header
3668 * at the specified offset from the beginning of that header.
3669 *
3670 * XXX - this handles a variable-length prefix preceding the link-layer
3671 * header, such as the radiotap or AVS radio prefix, but doesn't handle
3672 * variable-length link-layer headers (such as Token Ring or 802.11
3673 * headers).
3674 */
3675 static struct block *
3676 gen_portatom(off, v)
3677 int off;
3678 bpf_int32 v;
3679 {
3680 return gen_cmp(OR_TRAN_IPV4, off, BPF_H, v);
3681 }
3682
3683 #ifdef INET6
3684 static struct block *
3685 gen_portatom6(off, v)
3686 int off;
3687 bpf_int32 v;
3688 {
3689 return gen_cmp(OR_TRAN_IPV6, off, BPF_H, v);
3690 }
3691 #endif/*INET6*/
3692
3693 struct block *
3694 gen_portop(port, proto, dir)
3695 int port, proto, dir;
3696 {
3697 struct block *b0, *b1, *tmp;
3698
3699 /* ip proto 'proto' */
3700 tmp = gen_cmp(OR_NET, 9, BPF_B, (bpf_int32)proto);
3701 b0 = gen_ipfrag();
3702 gen_and(tmp, b0);
3703
3704 switch (dir) {
3705 case Q_SRC:
3706 b1 = gen_portatom(0, (bpf_int32)port);
3707 break;
3708
3709 case Q_DST:
3710 b1 = gen_portatom(2, (bpf_int32)port);
3711 break;
3712
3713 case Q_OR:
3714 case Q_DEFAULT:
3715 tmp = gen_portatom(0, (bpf_int32)port);
3716 b1 = gen_portatom(2, (bpf_int32)port);
3717 gen_or(tmp, b1);
3718 break;
3719
3720 case Q_AND:
3721 tmp = gen_portatom(0, (bpf_int32)port);
3722 b1 = gen_portatom(2, (bpf_int32)port);
3723 gen_and(tmp, b1);
3724 break;
3725
3726 default:
3727 abort();
3728 }
3729 gen_and(b0, b1);
3730
3731 return b1;
3732 }
3733
3734 static struct block *
3735 gen_port(port, ip_proto, dir)
3736 int port;
3737 int ip_proto;
3738 int dir;
3739 {
3740 struct block *b0, *b1, *tmp;
3741
3742 /*
3743 * ether proto ip
3744 *
3745 * For FDDI, RFC 1188 says that SNAP encapsulation is used,
3746 * not LLC encapsulation with LLCSAP_IP.
3747 *
3748 * For IEEE 802 networks - which includes 802.5 token ring
3749 * (which is what DLT_IEEE802 means) and 802.11 - RFC 1042
3750 * says that SNAP encapsulation is used, not LLC encapsulation
3751 * with LLCSAP_IP.
3752 *
3753 * For LLC-encapsulated ATM/"Classical IP", RFC 1483 and
3754 * RFC 2225 say that SNAP encapsulation is used, not LLC
3755 * encapsulation with LLCSAP_IP.
3756 *
3757 * So we always check for ETHERTYPE_IP.
3758 */
3759 b0 = gen_linktype(ETHERTYPE_IP);
3760
3761 switch (ip_proto) {
3762 case IPPROTO_UDP:
3763 case IPPROTO_TCP:
3764 case IPPROTO_SCTP:
3765 b1 = gen_portop(port, ip_proto, dir);
3766 break;
3767
3768 case PROTO_UNDEF:
3769 tmp = gen_portop(port, IPPROTO_TCP, dir);
3770 b1 = gen_portop(port, IPPROTO_UDP, dir);
3771 gen_or(tmp, b1);
3772 tmp = gen_portop(port, IPPROTO_SCTP, dir);
3773 gen_or(tmp, b1);
3774 break;
3775
3776 default:
3777 abort();
3778 }
3779 gen_and(b0, b1);
3780 return b1;
3781 }
3782
3783 #ifdef INET6
3784 struct block *
3785 gen_portop6(port, proto, dir)
3786 int port, proto, dir;
3787 {
3788 struct block *b0, *b1, *tmp;
3789
3790 /* ip6 proto 'proto' */
3791 b0 = gen_cmp(OR_NET, 6, BPF_B, (bpf_int32)proto);
3792
3793 switch (dir) {
3794 case Q_SRC:
3795 b1 = gen_portatom6(0, (bpf_int32)port);
3796 break;
3797
3798 case Q_DST:
3799 b1 = gen_portatom6(2, (bpf_int32)port);
3800 break;
3801
3802 case Q_OR:
3803 case Q_DEFAULT:
3804 tmp = gen_portatom6(0, (bpf_int32)port);
3805 b1 = gen_portatom6(2, (bpf_int32)port);
3806 gen_or(tmp, b1);
3807 break;
3808
3809 case Q_AND:
3810 tmp = gen_portatom6(0, (bpf_int32)port);
3811 b1 = gen_portatom6(2, (bpf_int32)port);
3812 gen_and(tmp, b1);
3813 break;
3814
3815 default:
3816 abort();
3817 }
3818 gen_and(b0, b1);
3819
3820 return b1;
3821 }
3822
3823 static struct block *
3824 gen_port6(port, ip_proto, dir)
3825 int port;
3826 int ip_proto;
3827 int dir;
3828 {
3829 struct block *b0, *b1, *tmp;
3830
3831 /* link proto ip6 */
3832 b0 = gen_linktype(ETHERTYPE_IPV6);
3833
3834 switch (ip_proto) {
3835 case IPPROTO_UDP:
3836 case IPPROTO_TCP:
3837 case IPPROTO_SCTP:
3838 b1 = gen_portop6(port, ip_proto, dir);
3839 break;
3840
3841 case PROTO_UNDEF:
3842 tmp = gen_portop6(port, IPPROTO_TCP, dir);
3843 b1 = gen_portop6(port, IPPROTO_UDP, dir);
3844 gen_or(tmp, b1);
3845 tmp = gen_portop6(port, IPPROTO_SCTP, dir);
3846 gen_or(tmp, b1);
3847 break;
3848
3849 default:
3850 abort();
3851 }
3852 gen_and(b0, b1);
3853 return b1;
3854 }
3855 #endif /* INET6 */
3856
3857 /* gen_portrange code */
3858 static struct block *
3859 gen_portrangeatom(off, v1, v2)
3860 int off;
3861 bpf_int32 v1, v2;
3862 {
3863 struct block *b1, *b2;
3864
3865 if (v1 > v2) {
3866 /*
3867 * Reverse the order of the ports, so v1 is the lower one.
3868 */
3869 bpf_int32 vtemp;
3870
3871 vtemp = v1;
3872 v1 = v2;
3873 v2 = vtemp;
3874 }
3875
3876 b1 = gen_cmp_ge(OR_TRAN_IPV4, off, BPF_H, v1);
3877 b2 = gen_cmp_le(OR_TRAN_IPV4, off, BPF_H, v2);
3878
3879 gen_and(b1, b2);
3880
3881 return b2;
3882 }
3883
3884 struct block *
3885 gen_portrangeop(port1, port2, proto, dir)
3886 int port1, port2;
3887 int proto;
3888 int dir;
3889 {
3890 struct block *b0, *b1, *tmp;
3891
3892 /* ip proto 'proto' */
3893 tmp = gen_cmp(OR_NET, 9, BPF_B, (bpf_int32)proto);
3894 b0 = gen_ipfrag();
3895 gen_and(tmp, b0);
3896
3897 switch (dir) {
3898 case Q_SRC:
3899 b1 = gen_portrangeatom(0, (bpf_int32)port1, (bpf_int32)port2);
3900 break;
3901
3902 case Q_DST:
3903 b1 = gen_portrangeatom(2, (bpf_int32)port1, (bpf_int32)port2);
3904 break;
3905
3906 case Q_OR:
3907 case Q_DEFAULT:
3908 tmp = gen_portrangeatom(0, (bpf_int32)port1, (bpf_int32)port2);
3909 b1 = gen_portrangeatom(2, (bpf_int32)port1, (bpf_int32)port2);
3910 gen_or(tmp, b1);
3911 break;
3912
3913 case Q_AND:
3914 tmp = gen_portrangeatom(0, (bpf_int32)port1, (bpf_int32)port2);
3915 b1 = gen_portrangeatom(2, (bpf_int32)port1, (bpf_int32)port2);
3916 gen_and(tmp, b1);
3917 break;
3918
3919 default:
3920 abort();
3921 }
3922 gen_and(b0, b1);
3923
3924 return b1;
3925 }
3926
3927 static struct block *
3928 gen_portrange(port1, port2, ip_proto, dir)
3929 int port1, port2;
3930 int ip_proto;
3931 int dir;
3932 {
3933 struct block *b0, *b1, *tmp;
3934
3935 /* link proto ip */
3936 b0 = gen_linktype(ETHERTYPE_IP);
3937
3938 switch (ip_proto) {
3939 case IPPROTO_UDP:
3940 case IPPROTO_TCP:
3941 case IPPROTO_SCTP:
3942 b1 = gen_portrangeop(port1, port2, ip_proto, dir);
3943 break;
3944
3945 case PROTO_UNDEF:
3946 tmp = gen_portrangeop(port1, port2, IPPROTO_TCP, dir);
3947 b1 = gen_portrangeop(port1, port2, IPPROTO_UDP, dir);
3948 gen_or(tmp, b1);
3949 tmp = gen_portrangeop(port1, port2, IPPROTO_SCTP, dir);
3950 gen_or(tmp, b1);
3951 break;
3952
3953 default:
3954 abort();
3955 }
3956 gen_and(b0, b1);
3957 return b1;
3958 }
3959
3960 #ifdef INET6
3961 static struct block *
3962 gen_portrangeatom6(off, v1, v2)
3963 int off;
3964 bpf_int32 v1, v2;
3965 {
3966 struct block *b1, *b2;
3967
3968 if (v1 > v2) {
3969 /*
3970 * Reverse the order of the ports, so v1 is the lower one.
3971 */
3972 bpf_int32 vtemp;
3973
3974 vtemp = v1;
3975 v1 = v2;
3976 v2 = vtemp;
3977 }
3978
3979 b1 = gen_cmp_ge(OR_TRAN_IPV6, off, BPF_H, v1);
3980 b2 = gen_cmp_le(OR_TRAN_IPV6, off, BPF_H, v2);
3981
3982 gen_and(b1, b2);
3983
3984 return b2;
3985 }
3986
3987 struct block *
3988 gen_portrangeop6(port1, port2, proto, dir)
3989 int port1, port2;
3990 int proto;
3991 int dir;
3992 {
3993 struct block *b0, *b1, *tmp;
3994
3995 /* ip6 proto 'proto' */
3996 b0 = gen_cmp(OR_NET, 6, BPF_B, (bpf_int32)proto);
3997
3998 switch (dir) {
3999 case Q_SRC:
4000 b1 = gen_portrangeatom6(0, (bpf_int32)port1, (bpf_int32)port2);
4001 break;
4002
4003 case Q_DST:
4004 b1 = gen_portrangeatom6(2, (bpf_int32)port1, (bpf_int32)port2);
4005 break;
4006
4007 case Q_OR:
4008 case Q_DEFAULT:
4009 tmp = gen_portrangeatom6(0, (bpf_int32)port1, (bpf_int32)port2);
4010 b1 = gen_portrangeatom6(2, (bpf_int32)port1, (bpf_int32)port2);
4011 gen_or(tmp, b1);
4012 break;
4013
4014 case Q_AND:
4015 tmp = gen_portrangeatom6(0, (bpf_int32)port1, (bpf_int32)port2);
4016 b1 = gen_portrangeatom6(2, (bpf_int32)port1, (bpf_int32)port2);
4017 gen_and(tmp, b1);
4018 break;
4019
4020 default:
4021 abort();
4022 }
4023 gen_and(b0, b1);
4024
4025 return b1;
4026 }
4027
4028 static struct block *
4029 gen_portrange6(port1, port2, ip_proto, dir)
4030 int port1, port2;
4031 int ip_proto;
4032 int dir;
4033 {
4034 struct block *b0, *b1, *tmp;
4035
4036 /* link proto ip6 */
4037 b0 = gen_linktype(ETHERTYPE_IPV6);
4038
4039 switch (ip_proto) {
4040 case IPPROTO_UDP:
4041 case IPPROTO_TCP:
4042 case IPPROTO_SCTP:
4043 b1 = gen_portrangeop6(port1, port2, ip_proto, dir);
4044 break;
4045
4046 case PROTO_UNDEF:
4047 tmp = gen_portrangeop6(port1, port2, IPPROTO_TCP, dir);
4048 b1 = gen_portrangeop6(port1, port2, IPPROTO_UDP, dir);
4049 gen_or(tmp, b1);
4050 tmp = gen_portrangeop6(port1, port2, IPPROTO_SCTP, dir);
4051 gen_or(tmp, b1);
4052 break;
4053
4054 default:
4055 abort();
4056 }
4057 gen_and(b0, b1);
4058 return b1;
4059 }
4060 #endif /* INET6 */
4061
4062 static int
4063 lookup_proto(name, proto)
4064 register const char *name;
4065 register int proto;
4066 {
4067 register int v;
4068
4069 switch (proto) {
4070
4071 case Q_DEFAULT:
4072 case Q_IP:
4073 case Q_IPV6:
4074 v = pcap_nametoproto(name);
4075 if (v == PROTO_UNDEF)
4076 bpf_error("unknown ip proto '%s'", name);
4077 break;
4078
4079 case Q_LINK:
4080 /* XXX should look up h/w protocol type based on linktype */
4081 v = pcap_nametoeproto(name);
4082 if (v == PROTO_UNDEF) {
4083 v = pcap_nametollc(name);
4084 if (v == PROTO_UNDEF)
4085 bpf_error("unknown ether proto '%s'", name);
4086 }
4087 break;
4088
4089 case Q_ISO:
4090 if (strcmp(name, "esis") == 0)
4091 v = ISO9542_ESIS;
4092 else if (strcmp(name, "isis") == 0)
4093 v = ISO10589_ISIS;
4094 else if (strcmp(name, "clnp") == 0)
4095 v = ISO8473_CLNP;
4096 else
4097 bpf_error("unknown osi proto '%s'", name);
4098 break;
4099
4100 default:
4101 v = PROTO_UNDEF;
4102 break;
4103 }
4104 return v;
4105 }
4106
4107 #if 0
4108 struct stmt *
4109 gen_joinsp(s, n)
4110 struct stmt **s;
4111 int n;
4112 {
4113 return NULL;
4114 }
4115 #endif
4116
4117 static struct block *
4118 gen_protochain(v, proto, dir)
4119 int v;
4120 int proto;
4121 int dir;
4122 {
4123 #ifdef NO_PROTOCHAIN
4124 return gen_proto(v, proto, dir);
4125 #else
4126 struct block *b0, *b;
4127 struct slist *s[100];
4128 int fix2, fix3, fix4, fix5;
4129 int ahcheck, again, end;
4130 int i, max;
4131 int reg2 = alloc_reg();
4132
4133 memset(s, 0, sizeof(s));
4134 fix2 = fix3 = fix4 = fix5 = 0;
4135
4136 switch (proto) {
4137 case Q_IP:
4138 case Q_IPV6:
4139 break;
4140 case Q_DEFAULT:
4141 b0 = gen_protochain(v, Q_IP, dir);
4142 b = gen_protochain(v, Q_IPV6, dir);
4143 gen_or(b0, b);
4144 return b;
4145 default:
4146 bpf_error("bad protocol applied for 'protochain'");
4147 /*NOTREACHED*/
4148 }
4149
4150 /*
4151 * We don't handle variable-length radiotap here headers yet.
4152 * We might want to add BPF instructions to do the protochain
4153 * work, to simplify that and, on platforms that have a BPF
4154 * interpreter with the new instructions, let the filtering
4155 * be done in the kernel. (We already require a modified BPF
4156 * engine to do the protochain stuff, to support backward
4157 * branches, and backward branch support is unlikely to appear
4158 * in kernel BPF engines.)
4159 */
4160 if (linktype == DLT_IEEE802_11_RADIO)
4161 bpf_error("'protochain' not supported with radiotap headers");
4162
4163 no_optimize = 1; /*this code is not compatible with optimzer yet */
4164
4165 /*
4166 * s[0] is a dummy entry to protect other BPF insn from damage
4167 * by s[fix] = foo with uninitialized variable "fix". It is somewhat
4168 * hard to find interdependency made by jump table fixup.
4169 */
4170 i = 0;
4171 s[i] = new_stmt(0); /*dummy*/
4172 i++;
4173
4174 switch (proto) {
4175 case Q_IP:
4176 b0 = gen_linktype(ETHERTYPE_IP);
4177
4178 /* A = ip->ip_p */
4179 s[i] = new_stmt(BPF_LD|BPF_ABS|BPF_B);
4180 s[i]->s.k = off_nl + 9;
4181 i++;
4182 /* X = ip->ip_hl << 2 */
4183 s[i] = new_stmt(BPF_LDX|BPF_MSH|BPF_B);
4184 s[i]->s.k = off_nl;
4185 i++;
4186 break;
4187 #ifdef INET6
4188 case Q_IPV6:
4189 b0 = gen_linktype(ETHERTYPE_IPV6);
4190
4191 /* A = ip6->ip_nxt */
4192 s[i] = new_stmt(BPF_LD|BPF_ABS|BPF_B);
4193 s[i]->s.k = off_nl + 6;
4194 i++;
4195 /* X = sizeof(struct ip6_hdr) */
4196 s[i] = new_stmt(BPF_LDX|BPF_IMM);
4197 s[i]->s.k = 40;
4198 i++;
4199 break;
4200 #endif
4201 default:
4202 bpf_error("unsupported proto to gen_protochain");
4203 /*NOTREACHED*/
4204 }
4205
4206 /* again: if (A == v) goto end; else fall through; */
4207 again = i;
4208 s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
4209 s[i]->s.k = v;
4210 s[i]->s.jt = NULL; /*later*/
4211 s[i]->s.jf = NULL; /*update in next stmt*/
4212 fix5 = i;
4213 i++;
4214
4215 #ifndef IPPROTO_NONE
4216 #define IPPROTO_NONE 59
4217 #endif
4218 /* if (A == IPPROTO_NONE) goto end */
4219 s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
4220 s[i]->s.jt = NULL; /*later*/
4221 s[i]->s.jf = NULL; /*update in next stmt*/
4222 s[i]->s.k = IPPROTO_NONE;
4223 s[fix5]->s.jf = s[i];
4224 fix2 = i;
4225 i++;
4226
4227 #ifdef INET6
4228 if (proto == Q_IPV6) {
4229 int v6start, v6end, v6advance, j;
4230
4231 v6start = i;
4232 /* if (A == IPPROTO_HOPOPTS) goto v6advance */
4233 s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
4234 s[i]->s.jt = NULL; /*later*/
4235 s[i]->s.jf = NULL; /*update in next stmt*/
4236 s[i]->s.k = IPPROTO_HOPOPTS;
4237 s[fix2]->s.jf = s[i];
4238 i++;
4239 /* if (A == IPPROTO_DSTOPTS) goto v6advance */
4240 s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
4241 s[i]->s.jt = NULL; /*later*/
4242 s[i]->s.jf = NULL; /*update in next stmt*/
4243 s[i]->s.k = IPPROTO_DSTOPTS;
4244 i++;
4245 /* if (A == IPPROTO_ROUTING) goto v6advance */
4246 s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
4247 s[i]->s.jt = NULL; /*later*/
4248 s[i]->s.jf = NULL; /*update in next stmt*/
4249 s[i]->s.k = IPPROTO_ROUTING;
4250 i++;
4251 /* if (A == IPPROTO_FRAGMENT) goto v6advance; else goto ahcheck; */
4252 s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
4253 s[i]->s.jt = NULL; /*later*/
4254 s[i]->s.jf = NULL; /*later*/
4255 s[i]->s.k = IPPROTO_FRAGMENT;
4256 fix3 = i;
4257 v6end = i;
4258 i++;
4259
4260 /* v6advance: */
4261 v6advance = i;
4262
4263 /*
4264 * in short,
4265 * A = P[X];
4266 * X = X + (P[X + 1] + 1) * 8;
4267 */
4268 /* A = X */
4269 s[i] = new_stmt(BPF_MISC|BPF_TXA);
4270 i++;
4271 /* A = P[X + packet head] */
4272 s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B);
4273 s[i]->s.k = off_nl;
4274 i++;
4275 /* MEM[reg2] = A */
4276 s[i] = new_stmt(BPF_ST);
4277 s[i]->s.k = reg2;
4278 i++;
4279 /* A = X */
4280 s[i] = new_stmt(BPF_MISC|BPF_TXA);
4281 i++;
4282 /* A += 1 */
4283 s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
4284 s[i]->s.k = 1;
4285 i++;
4286 /* X = A */
4287 s[i] = new_stmt(BPF_MISC|BPF_TAX);
4288 i++;
4289 /* A = P[X + packet head]; */
4290 s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B);
4291 s[i]->s.k = off_nl;
4292 i++;
4293 /* A += 1 */
4294 s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
4295 s[i]->s.k = 1;
4296 i++;
4297 /* A *= 8 */
4298 s[i] = new_stmt(BPF_ALU|BPF_MUL|BPF_K);
4299 s[i]->s.k = 8;
4300 i++;
4301 /* X = A; */
4302 s[i] = new_stmt(BPF_MISC|BPF_TAX);
4303 i++;
4304 /* A = MEM[reg2] */
4305 s[i] = new_stmt(BPF_LD|BPF_MEM);
4306 s[i]->s.k = reg2;
4307 i++;
4308
4309 /* goto again; (must use BPF_JA for backward jump) */
4310 s[i] = new_stmt(BPF_JMP|BPF_JA);
4311 s[i]->s.k = again - i - 1;
4312 s[i - 1]->s.jf = s[i];
4313 i++;
4314
4315 /* fixup */
4316 for (j = v6start; j <= v6end; j++)
4317 s[j]->s.jt = s[v6advance];
4318 } else
4319 #endif
4320 {
4321 /* nop */
4322 s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
4323 s[i]->s.k = 0;
4324 s[fix2]->s.jf = s[i];
4325 i++;
4326 }
4327
4328 /* ahcheck: */
4329 ahcheck = i;
4330 /* if (A == IPPROTO_AH) then fall through; else goto end; */
4331 s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
4332 s[i]->s.jt = NULL; /*later*/
4333 s[i]->s.jf = NULL; /*later*/
4334 s[i]->s.k = IPPROTO_AH;
4335 if (fix3)
4336 s[fix3]->s.jf = s[ahcheck];
4337 fix4 = i;
4338 i++;
4339
4340 /*
4341 * in short,
4342 * A = P[X];
4343 * X = X + (P[X + 1] + 2) * 4;
4344 */
4345 /* A = X */
4346 s[i - 1]->s.jt = s[i] = new_stmt(BPF_MISC|BPF_TXA);
4347 i++;
4348 /* A = P[X + packet head]; */
4349 s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B);
4350 s[i]->s.k = off_nl;
4351 i++;
4352 /* MEM[reg2] = A */
4353 s[i] = new_stmt(BPF_ST);
4354 s[i]->s.k = reg2;
4355 i++;
4356 /* A = X */
4357 s[i - 1]->s.jt = s[i] = new_stmt(BPF_MISC|BPF_TXA);
4358 i++;
4359 /* A += 1 */
4360 s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
4361 s[i]->s.k = 1;
4362 i++;
4363 /* X = A */
4364 s[i] = new_stmt(BPF_MISC|BPF_TAX);
4365 i++;
4366 /* A = P[X + packet head] */
4367 s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B);
4368 s[i]->s.k = off_nl;
4369 i++;
4370 /* A += 2 */
4371 s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
4372 s[i]->s.k = 2;
4373 i++;
4374 /* A *= 4 */
4375 s[i] = new_stmt(BPF_ALU|BPF_MUL|BPF_K);
4376 s[i]->s.k = 4;
4377 i++;
4378 /* X = A; */
4379 s[i] = new_stmt(BPF_MISC|BPF_TAX);
4380 i++;
4381 /* A = MEM[reg2] */
4382 s[i] = new_stmt(BPF_LD|BPF_MEM);
4383 s[i]->s.k = reg2;
4384 i++;
4385
4386 /* goto again; (must use BPF_JA for backward jump) */
4387 s[i] = new_stmt(BPF_JMP|BPF_JA);
4388 s[i]->s.k = again - i - 1;
4389 i++;
4390
4391 /* end: nop */
4392 end = i;
4393 s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
4394 s[i]->s.k = 0;
4395 s[fix2]->s.jt = s[end];
4396 s[fix4]->s.jf = s[end];
4397 s[fix5]->s.jt = s[end];
4398 i++;
4399
4400 /*
4401 * make slist chain
4402 */
4403 max = i;
4404 for (i = 0; i < max - 1; i++)
4405 s[i]->next = s[i + 1];
4406 s[max - 1]->next = NULL;
4407
4408 /*
4409 * emit final check
4410 */
4411 b = new_block(JMP(BPF_JEQ));
4412 b->stmts = s[1]; /*remember, s[0] is dummy*/
4413 b->s.k = v;
4414
4415 free_reg(reg2);
4416
4417 gen_and(b0, b);
4418 return b;
4419 #endif
4420 }
4421
4422 /*
4423 * Generate code that checks whether the packet is a packet for protocol
4424 * <proto> and whether the type field in that protocol's header has
4425 * the value <v>, e.g. if <proto> is Q_IP, it checks whether it's an
4426 * IP packet and checks the protocol number in the IP header against <v>.
4427 *
4428 * If <proto> is Q_DEFAULT, i.e. just "proto" was specified, it checks
4429 * against Q_IP and Q_IPV6.
4430 */
4431 static struct block *
4432 gen_proto(v, proto, dir)
4433 int v;
4434 int proto;
4435 int dir;
4436 {
4437 struct block *b0, *b1;
4438
4439 if (dir != Q_DEFAULT)
4440 bpf_error("direction applied to 'proto'");
4441
4442 switch (proto) {
4443 case Q_DEFAULT:
4444 #ifdef INET6
4445 b0 = gen_proto(v, Q_IP, dir);
4446 b1 = gen_proto(v, Q_IPV6, dir);
4447 gen_or(b0, b1);
4448 return b1;
4449 #else
4450 /*FALLTHROUGH*/
4451 #endif
4452 case Q_IP:
4453 /*
4454 * For FDDI, RFC 1188 says that SNAP encapsulation is used,
4455 * not LLC encapsulation with LLCSAP_IP.
4456 *
4457 * For IEEE 802 networks - which includes 802.5 token ring
4458 * (which is what DLT_IEEE802 means) and 802.11 - RFC 1042
4459 * says that SNAP encapsulation is used, not LLC encapsulation
4460 * with LLCSAP_IP.
4461 *
4462 * For LLC-encapsulated ATM/"Classical IP", RFC 1483 and
4463 * RFC 2225 say that SNAP encapsulation is used, not LLC
4464 * encapsulation with LLCSAP_IP.
4465 *
4466 * So we always check for ETHERTYPE_IP.
4467 */
4468
4469 b0 = gen_linktype(ETHERTYPE_IP);
4470 #ifndef CHASE_CHAIN
4471 b1 = gen_cmp(OR_NET, 9, BPF_B, (bpf_int32)v);
4472 #else
4473 b1 = gen_protochain(v, Q_IP);
4474 #endif
4475 gen_and(b0, b1);
4476 return b1;
4477
4478 case Q_ISO:
4479 switch (linktype) {
4480
4481 case DLT_FRELAY:
4482 /*
4483 * Frame Relay packets typically have an OSI
4484 * NLPID at the beginning; "gen_linktype(LLCSAP_ISONS)"
4485 * generates code to check for all the OSI
4486 * NLPIDs, so calling it and then adding a check
4487 * for the particular NLPID for which we're
4488 * looking is bogus, as we can just check for
4489 * the NLPID.
4490 *
4491 * What we check for is the NLPID and a frame
4492 * control field value of UI, i.e. 0x03 followed
4493 * by the NLPID.
4494 *
4495 * XXX - assumes a 2-byte Frame Relay header with
4496 * DLCI and flags. What if the address is longer?
4497 *
4498 * XXX - what about SNAP-encapsulated frames?
4499 */
4500 return gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | v);
4501 /*NOTREACHED*/
4502 break;
4503
4504 case DLT_C_HDLC:
4505 /*
4506 * Cisco uses an Ethertype lookalike - for OSI,
4507 * it's 0xfefe.
4508 */
4509 b0 = gen_linktype(LLCSAP_ISONS<<8 | LLCSAP_ISONS);
4510 /* OSI in C-HDLC is stuffed with a fudge byte */
4511 b1 = gen_cmp(OR_NET_NOSNAP, 1, BPF_B, (long)v);
4512 gen_and(b0, b1);
4513 return b1;
4514
4515 default:
4516 b0 = gen_linktype(LLCSAP_ISONS);
4517 b1 = gen_cmp(OR_NET_NOSNAP, 0, BPF_B, (long)v);
4518 gen_and(b0, b1);
4519 return b1;
4520 }
4521
4522 case Q_ISIS:
4523 b0 = gen_proto(ISO10589_ISIS, Q_ISO, Q_DEFAULT);
4524 /*
4525 * 4 is the offset of the PDU type relative to the IS-IS
4526 * header.
4527 */
4528 b1 = gen_cmp(OR_NET_NOSNAP, 4, BPF_B, (long)v);
4529 gen_and(b0, b1);
4530 return b1;
4531
4532 case Q_ARP:
4533 bpf_error("arp does not encapsulate another protocol");
4534 /* NOTREACHED */
4535
4536 case Q_RARP:
4537 bpf_error("rarp does not encapsulate another protocol");
4538 /* NOTREACHED */
4539
4540 case Q_ATALK:
4541 bpf_error("atalk encapsulation is not specifiable");
4542 /* NOTREACHED */
4543
4544 case Q_DECNET:
4545 bpf_error("decnet encapsulation is not specifiable");
4546 /* NOTREACHED */
4547
4548 case Q_SCA:
4549 bpf_error("sca does not encapsulate another protocol");
4550 /* NOTREACHED */
4551
4552 case Q_LAT:
4553 bpf_error("lat does not encapsulate another protocol");
4554 /* NOTREACHED */
4555
4556 case Q_MOPRC:
4557 bpf_error("moprc does not encapsulate another protocol");
4558 /* NOTREACHED */
4559
4560 case Q_MOPDL:
4561 bpf_error("mopdl does not encapsulate another protocol");
4562 /* NOTREACHED */
4563
4564 case Q_LINK:
4565 return gen_linktype(v);
4566
4567 case Q_UDP:
4568 bpf_error("'udp proto' is bogus");
4569 /* NOTREACHED */
4570
4571 case Q_TCP:
4572 bpf_error("'tcp proto' is bogus");
4573 /* NOTREACHED */
4574
4575 case Q_SCTP:
4576 bpf_error("'sctp proto' is bogus");
4577 /* NOTREACHED */
4578
4579 case Q_ICMP:
4580 bpf_error("'icmp proto' is bogus");
4581 /* NOTREACHED */
4582
4583 case Q_IGMP:
4584 bpf_error("'igmp proto' is bogus");
4585 /* NOTREACHED */
4586
4587 case Q_IGRP:
4588 bpf_error("'igrp proto' is bogus");
4589 /* NOTREACHED */
4590
4591 case Q_PIM:
4592 bpf_error("'pim proto' is bogus");
4593 /* NOTREACHED */
4594
4595 case Q_VRRP:
4596 bpf_error("'vrrp proto' is bogus");
4597 /* NOTREACHED */
4598
4599 #ifdef INET6
4600 case Q_IPV6:
4601 b0 = gen_linktype(ETHERTYPE_IPV6);
4602 #ifndef CHASE_CHAIN
4603 b1 = gen_cmp(OR_NET, 6, BPF_B, (bpf_int32)v);
4604 #else
4605 b1 = gen_protochain(v, Q_IPV6);
4606 #endif
4607 gen_and(b0, b1);
4608 return b1;
4609
4610 case Q_ICMPV6:
4611 bpf_error("'icmp6 proto' is bogus");
4612 #endif /* INET6 */
4613
4614 case Q_AH:
4615 bpf_error("'ah proto' is bogus");
4616
4617 case Q_ESP:
4618 bpf_error("'ah proto' is bogus");
4619
4620 case Q_STP:
4621 bpf_error("'stp proto' is bogus");
4622
4623 case Q_IPX:
4624 bpf_error("'ipx proto' is bogus");
4625
4626 case Q_NETBEUI:
4627 bpf_error("'netbeui proto' is bogus");
4628
4629 case Q_RADIO:
4630 bpf_error("'radio proto' is bogus");
4631
4632 default:
4633 abort();
4634 /* NOTREACHED */
4635 }
4636 /* NOTREACHED */
4637 }
4638
4639 struct block *
4640 gen_scode(name, q)
4641 register const char *name;
4642 struct qual q;
4643 {
4644 int proto = q.proto;
4645 int dir = q.dir;
4646 int tproto;
4647 u_char *eaddr;
4648 bpf_u_int32 mask, addr;
4649 #ifndef INET6
4650 bpf_u_int32 **alist;
4651 #else
4652 int tproto6;
4653 struct sockaddr_in *sin;
4654 struct sockaddr_in6 *sin6;
4655 struct addrinfo *res, *res0;
4656 struct in6_addr mask128;
4657 #endif /*INET6*/
4658 struct block *b, *tmp;
4659 int port, real_proto;
4660 int port1, port2;
4661
4662 switch (q.addr) {
4663
4664 case Q_NET:
4665 addr = pcap_nametonetaddr(name);
4666 if (addr == 0)
4667 bpf_error("unknown network '%s'", name);
4668 /* Left justify network addr and calculate its network mask */
4669 mask = 0xffffffff;
4670 while (addr && (addr & 0xff000000) == 0) {
4671 addr <<= 8;
4672 mask <<= 8;
4673 }
4674 return gen_host(addr, mask, proto, dir);
4675
4676 case Q_DEFAULT:
4677 case Q_HOST:
4678 if (proto == Q_LINK) {
4679 switch (linktype) {
4680
4681 case DLT_EN10MB:
4682 eaddr = pcap_ether_hostton(name);
4683 if (eaddr == NULL)
4684 bpf_error(
4685 "unknown ether host '%s'", name);
4686 b = gen_ehostop(eaddr, dir);
4687 free(eaddr);
4688 return b;
4689
4690 case DLT_FDDI:
4691 eaddr = pcap_ether_hostton(name);
4692 if (eaddr == NULL)
4693 bpf_error(
4694 "unknown FDDI host '%s'", name);
4695 b = gen_fhostop(eaddr, dir);
4696 free(eaddr);
4697 return b;
4698
4699 case DLT_IEEE802:
4700 eaddr = pcap_ether_hostton(name);
4701 if (eaddr == NULL)
4702 bpf_error(
4703 "unknown token ring host '%s'", name);
4704 b = gen_thostop(eaddr, dir);
4705 free(eaddr);
4706 return b;
4707
4708 case DLT_IEEE802_11:
4709 case DLT_IEEE802_11_RADIO_AVS:
4710 case DLT_IEEE802_11_RADIO:
4711 case DLT_PRISM_HEADER:
4712 eaddr = pcap_ether_hostton(name);
4713 if (eaddr == NULL)
4714 bpf_error(
4715 "unknown 802.11 host '%s'", name);
4716 b = gen_wlanhostop(eaddr, dir);
4717 free(eaddr);
4718 return b;
4719
4720 case DLT_IP_OVER_FC:
4721 eaddr = pcap_ether_hostton(name);
4722 if (eaddr == NULL)
4723 bpf_error(
4724 "unknown Fibre Channel host '%s'", name);
4725 b = gen_ipfchostop(eaddr, dir);
4726 free(eaddr);
4727 return b;
4728
4729 case DLT_SUNATM:
4730 if (!is_lane)
4731 break;
4732
4733 /*
4734 * Check that the packet doesn't begin
4735 * with an LE Control marker. (We've
4736 * already generated a test for LANE.)
4737 */
4738 tmp = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS,
4739 BPF_H, 0xFF00);
4740 gen_not(tmp);
4741
4742 eaddr = pcap_ether_hostton(name);
4743 if (eaddr == NULL)
4744 bpf_error(
4745 "unknown ether host '%s'", name);
4746 b = gen_ehostop(eaddr, dir);
4747 gen_and(tmp, b);
4748 free(eaddr);
4749 return b;
4750 }
4751
4752 bpf_error("only ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel supports link-level host name");
4753 } else if (proto == Q_DECNET) {
4754 unsigned short dn_addr = __pcap_nametodnaddr(name);
4755 /*
4756 * I don't think DECNET hosts can be multihomed, so
4757 * there is no need to build up a list of addresses
4758 */
4759 return (gen_host(dn_addr, 0, proto, dir));
4760 } else {
4761 #ifndef INET6
4762 alist = pcap_nametoaddr(name);
4763 if (alist == NULL || *alist == NULL)
4764 bpf_error("unknown host '%s'", name);
4765 tproto = proto;
4766 if (off_linktype == (u_int)-1 && tproto == Q_DEFAULT)
4767 tproto = Q_IP;
4768 b = gen_host(**alist++, 0xffffffff, tproto, dir);
4769 while (*alist) {
4770 tmp = gen_host(**alist++, 0xffffffff,
4771 tproto, dir);
4772 gen_or(b, tmp);
4773 b = tmp;
4774 }
4775 return b;
4776 #else
4777 memset(&mask128, 0xff, sizeof(mask128));
4778 res0 = res = pcap_nametoaddrinfo(name);
4779 if (res == NULL)
4780 bpf_error("unknown host '%s'", name);
4781 b = tmp = NULL;
4782 tproto = tproto6 = proto;
4783 if (off_linktype == -1 && tproto == Q_DEFAULT) {
4784 tproto = Q_IP;
4785 tproto6 = Q_IPV6;
4786 }
4787 for (res = res0; res; res = res->ai_next) {
4788 switch (res->ai_family) {
4789 case AF_INET:
4790 if (tproto == Q_IPV6)
4791 continue;
4792
4793 sin = (struct sockaddr_in *)
4794 res->ai_addr;
4795 tmp = gen_host(ntohl(sin->sin_addr.s_addr),
4796 0xffffffff, tproto, dir);
4797 break;
4798 case AF_INET6:
4799 if (tproto6 == Q_IP)
4800 continue;
4801
4802 sin6 = (struct sockaddr_in6 *)
4803 res->ai_addr;
4804 tmp = gen_host6(&sin6->sin6_addr,
4805 &mask128, tproto6, dir);
4806 break;
4807 default:
4808 continue;
4809 }
4810 if (b)
4811 gen_or(b, tmp);
4812 b = tmp;
4813 }
4814 freeaddrinfo(res0);
4815 if (b == NULL) {
4816 bpf_error("unknown host '%s'%s", name,
4817 (proto == Q_DEFAULT)
4818 ? ""
4819 : " for specified address family");
4820 }
4821 return b;
4822 #endif /*INET6*/
4823 }
4824
4825 case Q_PORT:
4826 if (proto != Q_DEFAULT &&
4827 proto != Q_UDP && proto != Q_TCP && proto != Q_SCTP)
4828 bpf_error("illegal qualifier of 'port'");
4829 if (pcap_nametoport(name, &port, &real_proto) == 0)
4830 bpf_error("unknown port '%s'", name);
4831 if (proto == Q_UDP) {
4832 if (real_proto == IPPROTO_TCP)
4833 bpf_error("port '%s' is tcp", name);
4834 else if (real_proto == IPPROTO_SCTP)
4835 bpf_error("port '%s' is sctp", name);
4836 else
4837 /* override PROTO_UNDEF */
4838 real_proto = IPPROTO_UDP;
4839 }
4840 if (proto == Q_TCP) {
4841 if (real_proto == IPPROTO_UDP)
4842 bpf_error("port '%s' is udp", name);
4843
4844 else if (real_proto == IPPROTO_SCTP)
4845 bpf_error("port '%s' is sctp", name);
4846 else
4847 /* override PROTO_UNDEF */
4848 real_proto = IPPROTO_TCP;
4849 }
4850 if (proto == Q_SCTP) {
4851 if (real_proto == IPPROTO_UDP)
4852 bpf_error("port '%s' is udp", name);
4853
4854 else if (real_proto == IPPROTO_TCP)
4855 bpf_error("port '%s' is tcp", name);
4856 else
4857 /* override PROTO_UNDEF */
4858 real_proto = IPPROTO_SCTP;
4859 }
4860 #ifndef INET6
4861 return gen_port(port, real_proto, dir);
4862 #else
4863 {
4864 struct block *b;
4865 b = gen_port(port, real_proto, dir);
4866 gen_or(gen_port6(port, real_proto, dir), b);
4867 return b;
4868 }
4869 #endif /* INET6 */
4870
4871 case Q_PORTRANGE:
4872 if (proto != Q_DEFAULT &&
4873 proto != Q_UDP && proto != Q_TCP && proto != Q_SCTP)
4874 bpf_error("illegal qualifier of 'portrange'");
4875 if (pcap_nametoportrange(name, &port1, &port2, &real_proto) == 0)
4876 bpf_error("unknown port in range '%s'", name);
4877 if (proto == Q_UDP) {
4878 if (real_proto == IPPROTO_TCP)
4879 bpf_error("port in range '%s' is tcp", name);
4880 else if (real_proto == IPPROTO_SCTP)
4881 bpf_error("port in range '%s' is sctp", name);
4882 else
4883 /* override PROTO_UNDEF */
4884 real_proto = IPPROTO_UDP;
4885 }
4886 if (proto == Q_TCP) {
4887 if (real_proto == IPPROTO_UDP)
4888 bpf_error("port in range '%s' is udp", name);
4889 else if (real_proto == IPPROTO_SCTP)
4890 bpf_error("port in range '%s' is sctp", name);
4891 else
4892 /* override PROTO_UNDEF */
4893 real_proto = IPPROTO_TCP;
4894 }
4895 if (proto == Q_SCTP) {
4896 if (real_proto == IPPROTO_UDP)
4897 bpf_error("port in range '%s' is udp", name);
4898 else if (real_proto == IPPROTO_TCP)
4899 bpf_error("port in range '%s' is tcp", name);
4900 else
4901 /* override PROTO_UNDEF */
4902 real_proto = IPPROTO_SCTP;
4903 }
4904 #ifndef INET6
4905 return gen_portrange(port1, port2, real_proto, dir);
4906 #else
4907 {
4908 struct block *b;
4909 b = gen_portrange(port1, port2, real_proto, dir);
4910 gen_or(gen_portrange6(port1, port2, real_proto, dir), b);
4911 return b;
4912 }
4913 #endif /* INET6 */
4914
4915 case Q_GATEWAY:
4916 #ifndef INET6
4917 eaddr = pcap_ether_hostton(name);
4918 if (eaddr == NULL)
4919 bpf_error("unknown ether host: %s", name);
4920
4921 alist = pcap_nametoaddr(name);
4922 if (alist == NULL || *alist == NULL)
4923 bpf_error("unknown host '%s'", name);
4924 b = gen_gateway(eaddr, alist, proto, dir);
4925 free(eaddr);
4926 return b;
4927 #else
4928 bpf_error("'gateway' not supported in this configuration");
4929 #endif /*INET6*/
4930
4931 case Q_PROTO:
4932 real_proto = lookup_proto(name, proto);
4933 if (real_proto >= 0)
4934 return gen_proto(real_proto, proto, dir);
4935 else
4936 bpf_error("unknown protocol: %s", name);
4937
4938 case Q_PROTOCHAIN:
4939 real_proto = lookup_proto(name, proto);
4940 if (real_proto >= 0)
4941 return gen_protochain(real_proto, proto, dir);
4942 else
4943 bpf_error("unknown protocol: %s", name);
4944
4945
4946 case Q_UNDEF:
4947 syntax();
4948 /* NOTREACHED */
4949 }
4950 abort();
4951 /* NOTREACHED */
4952 }
4953
4954 struct block *
4955 gen_mcode(s1, s2, masklen, q)
4956 register const char *s1, *s2;
4957 register int masklen;
4958 struct qual q;
4959 {
4960 register int nlen, mlen;
4961 bpf_u_int32 n, m;
4962
4963 nlen = __pcap_atoin(s1, &n);
4964 /* Promote short ipaddr */
4965 n <<= 32 - nlen;
4966
4967 if (s2 != NULL) {
4968 mlen = __pcap_atoin(s2, &m);
4969 /* Promote short ipaddr */
4970 m <<= 32 - mlen;
4971 if ((n & ~m) != 0)
4972 bpf_error("non-network bits set in \"%s mask %s\"",
4973 s1, s2);
4974 } else {
4975 /* Convert mask len to mask */
4976 if (masklen > 32)
4977 bpf_error("mask length must be <= 32");
4978 m = 0xffffffff << (32 - masklen);
4979 if ((n & ~m) != 0)
4980 bpf_error("non-network bits set in \"%s/%d\"",
4981 s1, masklen);
4982 }
4983
4984 switch (q.addr) {
4985
4986 case Q_NET:
4987 return gen_host(n, m, q.proto, q.dir);
4988
4989 default:
4990 bpf_error("Mask syntax for networks only");
4991 /* NOTREACHED */
4992 }
4993 /* NOTREACHED */
4994 }
4995
4996 struct block *
4997 gen_ncode(s, v, q)
4998 register const char *s;
4999 bpf_u_int32 v;
5000 struct qual q;
5001 {
5002 bpf_u_int32 mask;
5003 int proto = q.proto;
5004 int dir = q.dir;
5005 register int vlen;
5006
5007 if (s == NULL)
5008 vlen = 32;
5009 else if (q.proto == Q_DECNET)
5010 vlen = __pcap_atodn(s, &v);
5011 else
5012 vlen = __pcap_atoin(s, &v);
5013
5014 switch (q.addr) {
5015
5016 case Q_DEFAULT:
5017 case Q_HOST:
5018 case Q_NET:
5019 if (proto == Q_DECNET)
5020 return gen_host(v, 0, proto, dir);
5021 else if (proto == Q_LINK) {
5022 bpf_error("illegal link layer address");
5023 } else {
5024 mask = 0xffffffff;
5025 if (s == NULL && q.addr == Q_NET) {
5026 /* Promote short net number */
5027 while (v && (v & 0xff000000) == 0) {
5028 v <<= 8;
5029 mask <<= 8;
5030 }
5031 } else {
5032 /* Promote short ipaddr */
5033 v <<= 32 - vlen;
5034 mask <<= 32 - vlen;
5035 }
5036 return gen_host(v, mask, proto, dir);
5037 }
5038
5039 case Q_PORT:
5040 if (proto == Q_UDP)
5041 proto = IPPROTO_UDP;
5042 else if (proto == Q_TCP)
5043 proto = IPPROTO_TCP;
5044 else if (proto == Q_SCTP)
5045 proto = IPPROTO_SCTP;
5046 else if (proto == Q_DEFAULT)
5047 proto = PROTO_UNDEF;
5048 else
5049 bpf_error("illegal qualifier of 'port'");
5050
5051 #ifndef INET6
5052 return gen_port((int)v, proto, dir);
5053 #else
5054 {
5055 struct block *b;
5056 b = gen_port((int)v, proto, dir);
5057 gen_or(gen_port6((int)v, proto, dir), b);
5058 return b;
5059 }
5060 #endif /* INET6 */
5061
5062 case Q_PORTRANGE:
5063 if (proto == Q_UDP)
5064 proto = IPPROTO_UDP;
5065 else if (proto == Q_TCP)
5066 proto = IPPROTO_TCP;
5067 else if (proto == Q_SCTP)
5068 proto = IPPROTO_SCTP;
5069 else if (proto == Q_DEFAULT)
5070 proto = PROTO_UNDEF;
5071 else
5072 bpf_error("illegal qualifier of 'portrange'");
5073
5074 #ifndef INET6
5075 return gen_portrange((int)v, (int)v, proto, dir);
5076 #else
5077 {
5078 struct block *b;
5079 b = gen_portrange((int)v, (int)v, proto, dir);
5080 gen_or(gen_portrange6((int)v, (int)v, proto, dir), b);
5081 return b;
5082 }
5083 #endif /* INET6 */
5084
5085 case Q_GATEWAY:
5086 bpf_error("'gateway' requires a name");
5087 /* NOTREACHED */
5088
5089 case Q_PROTO:
5090 return gen_proto((int)v, proto, dir);
5091
5092 case Q_PROTOCHAIN:
5093 return gen_protochain((int)v, proto, dir);
5094
5095 case Q_UNDEF:
5096 syntax();
5097 /* NOTREACHED */
5098
5099 default:
5100 abort();
5101 /* NOTREACHED */
5102 }
5103 /* NOTREACHED */
5104 }
5105
5106 #ifdef INET6
5107 struct block *
5108 gen_mcode6(s1, s2, masklen, q)
5109 register const char *s1, *s2;
5110 register int masklen;
5111 struct qual q;
5112 {
5113 struct addrinfo *res;
5114 struct in6_addr *addr;
5115 struct in6_addr mask;
5116 struct block *b;
5117 u_int32_t *a, *m;
5118
5119 if (s2)
5120 bpf_error("no mask %s supported", s2);
5121
5122 res = pcap_nametoaddrinfo(s1);
5123 if (!res)
5124 bpf_error("invalid ip6 address %s", s1);
5125 if (res->ai_next)
5126 bpf_error("%s resolved to multiple address", s1);
5127 addr = &((struct sockaddr_in6 *)res->ai_addr)->sin6_addr;
5128
5129 if (sizeof(mask) * 8 < masklen)
5130 bpf_error("mask length must be <= %u", (unsigned int)(sizeof(mask) * 8));
5131 memset(&mask, 0, sizeof(mask));
5132 memset(&mask, 0xff, masklen / 8);
5133 if (masklen % 8) {
5134 mask.s6_addr[masklen / 8] =
5135 (0xff << (8 - masklen % 8)) & 0xff;
5136 }
5137
5138 a = (u_int32_t *)addr;
5139 m = (u_int32_t *)&mask;
5140 if ((a[0] & ~m[0]) || (a[1] & ~m[1])
5141 || (a[2] & ~m[2]) || (a[3] & ~m[3])) {
5142 bpf_error("non-network bits set in \"%s/%d\"", s1, masklen);
5143 }
5144
5145 switch (q.addr) {
5146
5147 case Q_DEFAULT:
5148 case Q_HOST:
5149 if (masklen != 128)
5150 bpf_error("Mask syntax for networks only");
5151 /* FALLTHROUGH */
5152
5153 case Q_NET:
5154 b = gen_host6(addr, &mask, q.proto, q.dir);
5155 freeaddrinfo(res);
5156 return b;
5157
5158 default:
5159 bpf_error("invalid qualifier against IPv6 address");
5160 /* NOTREACHED */
5161 }
5162 }
5163 #endif /*INET6*/
5164
5165 struct block *
5166 gen_ecode(eaddr, q)
5167 register const u_char *eaddr;
5168 struct qual q;
5169 {
5170 struct block *b, *tmp;
5171
5172 if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK) {
5173 if (linktype == DLT_EN10MB)
5174 return gen_ehostop(eaddr, (int)q.dir);
5175 if (linktype == DLT_FDDI)
5176 return gen_fhostop(eaddr, (int)q.dir);
5177 if (linktype == DLT_IEEE802)
5178 return gen_thostop(eaddr, (int)q.dir);
5179 if (linktype == DLT_IEEE802_11 ||
5180 linktype == DLT_IEEE802_11_RADIO_AVS ||
5181 linktype == DLT_IEEE802_11_RADIO ||
5182 linktype == DLT_PRISM_HEADER)
5183 return gen_wlanhostop(eaddr, (int)q.dir);
5184 if (linktype == DLT_SUNATM && is_lane) {
5185 /*
5186 * Check that the packet doesn't begin with an
5187 * LE Control marker. (We've already generated
5188 * a test for LANE.)
5189 */
5190 tmp = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS, BPF_H,
5191 0xFF00);
5192 gen_not(tmp);
5193
5194 /*
5195 * Now check the MAC address.
5196 */
5197 b = gen_ehostop(eaddr, (int)q.dir);
5198 gen_and(tmp, b);
5199 return b;
5200 }
5201 if (linktype == DLT_IP_OVER_FC)
5202 return gen_ipfchostop(eaddr, (int)q.dir);
5203 bpf_error("ethernet addresses supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
5204 }
5205 bpf_error("ethernet address used in non-ether expression");
5206 /* NOTREACHED */
5207 }
5208
5209 void
5210 sappend(s0, s1)
5211 struct slist *s0, *s1;
5212 {
5213 /*
5214 * This is definitely not the best way to do this, but the
5215 * lists will rarely get long.
5216 */
5217 while (s0->next)
5218 s0 = s0->next;
5219 s0->next = s1;
5220 }
5221
5222 static struct slist *
5223 xfer_to_x(a)
5224 struct arth *a;
5225 {
5226 struct slist *s;
5227
5228 s = new_stmt(BPF_LDX|BPF_MEM);
5229 s->s.k = a->regno;
5230 return s;
5231 }
5232
5233 static struct slist *
5234 xfer_to_a(a)
5235 struct arth *a;
5236 {
5237 struct slist *s;
5238
5239 s = new_stmt(BPF_LD|BPF_MEM);
5240 s->s.k = a->regno;
5241 return s;
5242 }
5243
5244 /*
5245 * Modify "index" to use the value stored into its register as an
5246 * offset relative to the beginning of the header for the protocol
5247 * "proto", and allocate a register and put an item "size" bytes long
5248 * (1, 2, or 4) at that offset into that register, making it the register
5249 * for "index".
5250 */
5251 struct arth *
5252 gen_load(proto, index, size)
5253 int proto;
5254 struct arth *index;
5255 int size;
5256 {
5257 struct slist *s, *tmp;
5258 struct block *b;
5259 int regno = alloc_reg();
5260
5261 free_reg(index->regno);
5262 switch (size) {
5263
5264 default:
5265 bpf_error("data size must be 1, 2, or 4");
5266
5267 case 1:
5268 size = BPF_B;
5269 break;
5270
5271 case 2:
5272 size = BPF_H;
5273 break;
5274
5275 case 4:
5276 size = BPF_W;
5277 break;
5278 }
5279 switch (proto) {
5280 default:
5281 bpf_error("unsupported index operation");
5282
5283 case Q_RADIO:
5284 /*
5285 * The offset is relative to the beginning of the packet
5286 * data, if we have a radio header. (If we don't, this
5287 * is an error.)
5288 */
5289 if (linktype != DLT_IEEE802_11_RADIO_AVS &&
5290 linktype != DLT_IEEE802_11_RADIO &&
5291 linktype != DLT_PRISM_HEADER)
5292 bpf_error("radio information not present in capture");
5293
5294 /*
5295 * Load into the X register the offset computed into the
5296 * register specifed by "index".
5297 */
5298 s = xfer_to_x(index);
5299
5300 /*
5301 * Load the item at that offset.
5302 */
5303 tmp = new_stmt(BPF_LD|BPF_IND|size);
5304 sappend(s, tmp);
5305 sappend(index->s, s);
5306 break;
5307
5308 case Q_LINK:
5309 /*
5310 * The offset is relative to the beginning of
5311 * the link-layer header.
5312 *
5313 * XXX - what about ATM LANE? Should the index be
5314 * relative to the beginning of the AAL5 frame, so
5315 * that 0 refers to the beginning of the LE Control
5316 * field, or relative to the beginning of the LAN
5317 * frame, so that 0 refers, for Ethernet LANE, to
5318 * the beginning of the destination address?
5319 */
5320 s = gen_llprefixlen();
5321
5322 /*
5323 * If "s" is non-null, it has code to arrange that the
5324 * X register contains the length of the prefix preceding
5325 * the link-layer header. Add to it the offset computed
5326 * into the register specified by "index", and move that
5327 * into the X register. Otherwise, just load into the X
5328 * register the offset computed into the register specifed
5329 * by "index".
5330 */
5331 if (s != NULL) {
5332 sappend(s, xfer_to_a(index));
5333 sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X));
5334 sappend(s, new_stmt(BPF_MISC|BPF_TAX));
5335 } else
5336 s = xfer_to_x(index);
5337
5338 /*
5339 * Load the item at the sum of the offset we've put in the
5340 * X register and the offset of the start of the link
5341 * layer header (which is 0 if the radio header is
5342 * variable-length; that header length is what we put
5343 * into the X register and then added to the index).
5344 */
5345 tmp = new_stmt(BPF_LD|BPF_IND|size);
5346 tmp->s.k = off_ll;
5347 sappend(s, tmp);
5348 sappend(index->s, s);
5349 break;
5350
5351 case Q_IP:
5352 case Q_ARP:
5353 case Q_RARP:
5354 case Q_ATALK:
5355 case Q_DECNET:
5356 case Q_SCA:
5357 case Q_LAT:
5358 case Q_MOPRC:
5359 case Q_MOPDL:
5360 #ifdef INET6
5361 case Q_IPV6:
5362 #endif
5363 /*
5364 * The offset is relative to the beginning of
5365 * the network-layer header.
5366 * XXX - are there any cases where we want
5367 * off_nl_nosnap?
5368 */
5369 s = gen_llprefixlen();
5370
5371 /*
5372 * If "s" is non-null, it has code to arrange that the
5373 * X register contains the length of the prefix preceding
5374 * the link-layer header. Add to it the offset computed
5375 * into the register specified by "index", and move that
5376 * into the X register. Otherwise, just load into the X
5377 * register the offset computed into the register specifed
5378 * by "index".
5379 */
5380 if (s != NULL) {
5381 sappend(s, xfer_to_a(index));
5382 sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X));
5383 sappend(s, new_stmt(BPF_MISC|BPF_TAX));
5384 } else
5385 s = xfer_to_x(index);
5386
5387 /*
5388 * Load the item at the sum of the offset we've put in the
5389 * X register and the offset of the start of the network
5390 * layer header.
5391 */
5392 tmp = new_stmt(BPF_LD|BPF_IND|size);
5393 tmp->s.k = off_nl;
5394 sappend(s, tmp);
5395 sappend(index->s, s);
5396
5397 /*
5398 * Do the computation only if the packet contains
5399 * the protocol in question.
5400 */
5401 b = gen_proto_abbrev(proto);
5402 if (index->b)
5403 gen_and(index->b, b);
5404 index->b = b;
5405 break;
5406
5407 case Q_SCTP:
5408 case Q_TCP:
5409 case Q_UDP:
5410 case Q_ICMP:
5411 case Q_IGMP:
5412 case Q_IGRP:
5413 case Q_PIM:
5414 case Q_VRRP:
5415 /*
5416 * The offset is relative to the beginning of
5417 * the transport-layer header.
5418 * XXX - are there any cases where we want
5419 * off_nl_nosnap?
5420 * XXX - we should, if we're built with
5421 * IPv6 support, generate code to load either
5422 * IPv4, IPv6, or both, as appropriate.
5423 */
5424 s = gen_loadx_iphdrlen();
5425
5426 /*
5427 * The X register now contains the sum of the offset
5428 * of the beginning of the link-layer header and
5429 * the length of the network-layer header. Load
5430 * into the A register the offset relative to
5431 * the beginning of the transport layer header,
5432 * add the X register to that, move that to the
5433 * X register, and load with an offset from the
5434 * X register equal to the offset of the network
5435 * layer header relative to the beginning of
5436 * the link-layer header.
5437 */
5438 sappend(s, xfer_to_a(index));
5439 sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X));
5440 sappend(s, new_stmt(BPF_MISC|BPF_TAX));
5441 sappend(s, tmp = new_stmt(BPF_LD|BPF_IND|size));
5442 tmp->s.k = off_nl;
5443 sappend(index->s, s);
5444
5445 /*
5446 * Do the computation only if the packet contains
5447 * the protocol in question - which is true only
5448 * if this is an IP datagram and is the first or
5449 * only fragment of that datagram.
5450 */
5451 gen_and(gen_proto_abbrev(proto), b = gen_ipfrag());
5452 if (index->b)
5453 gen_and(index->b, b);
5454 #ifdef INET6
5455 gen_and(gen_proto_abbrev(Q_IP), b);
5456 #endif
5457 index->b = b;
5458 break;
5459 #ifdef INET6
5460 case Q_ICMPV6:
5461 bpf_error("IPv6 upper-layer protocol is not supported by proto[x]");
5462 /*NOTREACHED*/
5463 #endif
5464 }
5465 index->regno = regno;
5466 s = new_stmt(BPF_ST);
5467 s->s.k = regno;
5468 sappend(index->s, s);
5469
5470 return index;
5471 }
5472
5473 struct block *
5474 gen_relation(code, a0, a1, reversed)
5475 int code;
5476 struct arth *a0, *a1;
5477 int reversed;
5478 {
5479 struct slist *s0, *s1, *s2;
5480 struct block *b, *tmp;
5481
5482 s0 = xfer_to_x(a1);
5483 s1 = xfer_to_a(a0);
5484 if (code == BPF_JEQ) {
5485 s2 = new_stmt(BPF_ALU|BPF_SUB|BPF_X);
5486 b = new_block(JMP(code));
5487 sappend(s1, s2);
5488 }
5489 else
5490 b = new_block(BPF_JMP|code|BPF_X);
5491 if (reversed)
5492 gen_not(b);
5493
5494 sappend(s0, s1);
5495 sappend(a1->s, s0);
5496 sappend(a0->s, a1->s);
5497
5498 b->stmts = a0->s;
5499
5500 free_reg(a0->regno);
5501 free_reg(a1->regno);
5502
5503 /* 'and' together protocol checks */
5504 if (a0->b) {
5505 if (a1->b) {
5506 gen_and(a0->b, tmp = a1->b);
5507 }
5508 else
5509 tmp = a0->b;
5510 } else
5511 tmp = a1->b;
5512
5513 if (tmp)
5514 gen_and(tmp, b);
5515
5516 return b;
5517 }
5518
5519 struct arth *
5520 gen_loadlen()
5521 {
5522 int regno = alloc_reg();
5523 struct arth *a = (struct arth *)newchunk(sizeof(*a));
5524 struct slist *s;
5525
5526 s = new_stmt(BPF_LD|BPF_LEN);
5527 s->next = new_stmt(BPF_ST);
5528 s->next->s.k = regno;
5529 a->s = s;
5530 a->regno = regno;
5531
5532 return a;
5533 }
5534
5535 struct arth *
5536 gen_loadi(val)
5537 int val;
5538 {
5539 struct arth *a;
5540 struct slist *s;
5541 int reg;
5542
5543 a = (struct arth *)newchunk(sizeof(*a));
5544
5545 reg = alloc_reg();
5546
5547 s = new_stmt(BPF_LD|BPF_IMM);
5548 s->s.k = val;
5549 s->next = new_stmt(BPF_ST);
5550 s->next->s.k = reg;
5551 a->s = s;
5552 a->regno = reg;
5553
5554 return a;
5555 }
5556
5557 struct arth *
5558 gen_neg(a)
5559 struct arth *a;
5560 {
5561 struct slist *s;
5562
5563 s = xfer_to_a(a);
5564 sappend(a->s, s);
5565 s = new_stmt(BPF_ALU|BPF_NEG);
5566 s->s.k = 0;
5567 sappend(a->s, s);
5568 s = new_stmt(BPF_ST);
5569 s->s.k = a->regno;
5570 sappend(a->s, s);
5571
5572 return a;
5573 }
5574
5575 struct arth *
5576 gen_arth(code, a0, a1)
5577 int code;
5578 struct arth *a0, *a1;
5579 {
5580 struct slist *s0, *s1, *s2;
5581
5582 s0 = xfer_to_x(a1);
5583 s1 = xfer_to_a(a0);
5584 s2 = new_stmt(BPF_ALU|BPF_X|code);
5585
5586 sappend(s1, s2);
5587 sappend(s0, s1);
5588 sappend(a1->s, s0);
5589 sappend(a0->s, a1->s);
5590
5591 free_reg(a0->regno);
5592 free_reg(a1->regno);
5593
5594 s0 = new_stmt(BPF_ST);
5595 a0->regno = s0->s.k = alloc_reg();
5596 sappend(a0->s, s0);
5597
5598 return a0;
5599 }
5600
5601 /*
5602 * Here we handle simple allocation of the scratch registers.
5603 * If too many registers are alloc'd, the allocator punts.
5604 */
5605 static int regused[BPF_MEMWORDS];
5606 static int curreg;
5607
5608 /*
5609 * Return the next free register.
5610 */
5611 static int
5612 alloc_reg()
5613 {
5614 int n = BPF_MEMWORDS;
5615
5616 while (--n >= 0) {
5617 if (regused[curreg])
5618 curreg = (curreg + 1) % BPF_MEMWORDS;
5619 else {
5620 regused[curreg] = 1;
5621 return curreg;
5622 }
5623 }
5624 bpf_error("too many registers needed to evaluate expression");
5625 /* NOTREACHED */
5626 }
5627
5628 /*
5629 * Return a register to the table so it can
5630 * be used later.
5631 */
5632 static void
5633 free_reg(n)
5634 int n;
5635 {
5636 regused[n] = 0;
5637 }
5638
5639 static struct block *
5640 gen_len(jmp, n)
5641 int jmp, n;
5642 {
5643 struct slist *s;
5644 struct block *b;
5645
5646 s = new_stmt(BPF_LD|BPF_LEN);
5647 b = new_block(JMP(jmp));
5648 b->stmts = s;
5649 b->s.k = n;
5650
5651 return b;
5652 }
5653
5654 struct block *
5655 gen_greater(n)
5656 int n;
5657 {
5658 return gen_len(BPF_JGE, n);
5659 }
5660
5661 /*
5662 * Actually, this is less than or equal.
5663 */
5664 struct block *
5665 gen_less(n)
5666 int n;
5667 {
5668 struct block *b;
5669
5670 b = gen_len(BPF_JGT, n);
5671 gen_not(b);
5672
5673 return b;
5674 }
5675
5676 /*
5677 * This is for "byte {idx} {op} {val}"; "idx" is treated as relative to
5678 * the beginning of the link-layer header.
5679 * XXX - that means you can't test values in the radiotap header, but
5680 * as that header is difficult if not impossible to parse generally
5681 * without a loop, that might not be a severe problem. A new keyword
5682 * "radio" could be added for that, although what you'd really want
5683 * would be a way of testing particular radio header values, which
5684 * would generate code appropriate to the radio header in question.
5685 */
5686 struct block *
5687 gen_byteop(op, idx, val)
5688 int op, idx, val;
5689 {
5690 struct block *b;
5691 struct slist *s;
5692
5693 switch (op) {
5694 default:
5695 abort();
5696
5697 case '=':
5698 return gen_cmp(OR_LINK, (u_int)idx, BPF_B, (bpf_int32)val);
5699
5700 case '<':
5701 b = gen_cmp_lt(OR_LINK, (u_int)idx, BPF_B, (bpf_int32)val);
5702 return b;
5703
5704 case '>':
5705 b = gen_cmp_gt(OR_LINK, (u_int)idx, BPF_B, (bpf_int32)val);
5706 return b;
5707
5708 case '|':
5709 s = new_stmt(BPF_ALU|BPF_OR|BPF_K);
5710 break;
5711
5712 case '&':
5713 s = new_stmt(BPF_ALU|BPF_AND|BPF_K);
5714 break;
5715 }
5716 s->s.k = val;
5717 b = new_block(JMP(BPF_JEQ));
5718 b->stmts = s;
5719 gen_not(b);
5720
5721 return b;
5722 }
5723
5724 static u_char abroadcast[] = { 0x0 };
5725
5726 struct block *
5727 gen_broadcast(proto)
5728 int proto;
5729 {
5730 bpf_u_int32 hostmask;
5731 struct block *b0, *b1, *b2;
5732 static u_char ebroadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
5733
5734 switch (proto) {
5735
5736 case Q_DEFAULT:
5737 case Q_LINK:
5738 if (linktype == DLT_ARCNET || linktype == DLT_ARCNET_LINUX)
5739 return gen_ahostop(abroadcast, Q_DST);
5740 if (linktype == DLT_EN10MB)
5741 return gen_ehostop(ebroadcast, Q_DST);
5742 if (linktype == DLT_FDDI)
5743 return gen_fhostop(ebroadcast, Q_DST);
5744 if (linktype == DLT_IEEE802)
5745 return gen_thostop(ebroadcast, Q_DST);
5746 if (linktype == DLT_IEEE802_11 ||
5747 linktype == DLT_IEEE802_11_RADIO_AVS ||
5748 linktype == DLT_IEEE802_11_RADIO ||
5749 linktype == DLT_PRISM_HEADER)
5750 return gen_wlanhostop(ebroadcast, Q_DST);
5751 if (linktype == DLT_IP_OVER_FC)
5752 return gen_ipfchostop(ebroadcast, Q_DST);
5753 if (linktype == DLT_SUNATM && is_lane) {
5754 /*
5755 * Check that the packet doesn't begin with an
5756 * LE Control marker. (We've already generated
5757 * a test for LANE.)
5758 */
5759 b1 = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS, BPF_H,
5760 0xFF00);
5761 gen_not(b1);
5762
5763 /*
5764 * Now check the MAC address.
5765 */
5766 b0 = gen_ehostop(ebroadcast, Q_DST);
5767 gen_and(b1, b0);
5768 return b0;
5769 }
5770 bpf_error("not a broadcast link");
5771 break;
5772
5773 case Q_IP:
5774 b0 = gen_linktype(ETHERTYPE_IP);
5775 hostmask = ~netmask;
5776 b1 = gen_mcmp(OR_NET, 16, BPF_W, (bpf_int32)0, hostmask);
5777 b2 = gen_mcmp(OR_NET, 16, BPF_W,
5778 (bpf_int32)(~0 & hostmask), hostmask);
5779 gen_or(b1, b2);
5780 gen_and(b0, b2);
5781 return b2;
5782 }
5783 bpf_error("only link-layer/IP broadcast filters supported");
5784 /* NOTREACHED */
5785 }
5786
5787 /*
5788 * Generate code to test the low-order bit of a MAC address (that's
5789 * the bottom bit of the *first* byte).
5790 */
5791 static struct block *
5792 gen_mac_multicast(offset)
5793 int offset;
5794 {
5795 register struct block *b0;
5796 register struct slist *s;
5797
5798 /* link[offset] & 1 != 0 */
5799 s = gen_load_a(OR_LINK, offset, BPF_B);
5800 b0 = new_block(JMP(BPF_JSET));
5801 b0->s.k = 1;
5802 b0->stmts = s;
5803 return b0;
5804 }
5805
5806 struct block *
5807 gen_multicast(proto)
5808 int proto;
5809 {
5810 register struct block *b0, *b1, *b2;
5811 register struct slist *s;
5812
5813 switch (proto) {
5814
5815 case Q_DEFAULT:
5816 case Q_LINK:
5817 if (linktype == DLT_ARCNET || linktype == DLT_ARCNET_LINUX)
5818 /* all ARCnet multicasts use the same address */
5819 return gen_ahostop(abroadcast, Q_DST);
5820
5821 if (linktype == DLT_EN10MB) {
5822 /* ether[0] & 1 != 0 */
5823 return gen_mac_multicast(0);
5824 }
5825
5826 if (linktype == DLT_FDDI) {
5827 /*
5828 * XXX TEST THIS: MIGHT NOT PORT PROPERLY XXX
5829 *
5830 * XXX - was that referring to bit-order issues?
5831 */
5832 /* fddi[1] & 1 != 0 */
5833 return gen_mac_multicast(1);
5834 }
5835
5836 if (linktype == DLT_IEEE802) {
5837 /* tr[2] & 1 != 0 */
5838 return gen_mac_multicast(2);
5839 }
5840
5841 if (linktype == DLT_IEEE802_11 ||
5842 linktype == DLT_IEEE802_11_RADIO_AVS ||
5843 linktype == DLT_IEEE802_11_RADIO ||
5844 linktype == DLT_PRISM_HEADER) {
5845 /*
5846 * Oh, yuk.
5847 *
5848 * For control frames, there is no DA.
5849 *
5850 * For management frames, DA is at an
5851 * offset of 4 from the beginning of
5852 * the packet.
5853 *
5854 * For data frames, DA is at an offset
5855 * of 4 from the beginning of the packet
5856 * if To DS is clear and at an offset of
5857 * 16 from the beginning of the packet
5858 * if To DS is set.
5859 */
5860
5861 /*
5862 * Generate the tests to be done for data frames.
5863 *
5864 * First, check for To DS set, i.e. "link[1] & 0x01".
5865 */
5866 s = gen_load_a(OR_LINK, 1, BPF_B);
5867 b1 = new_block(JMP(BPF_JSET));
5868 b1->s.k = 0x01; /* To DS */
5869 b1->stmts = s;
5870
5871 /*
5872 * If To DS is set, the DA is at 16.
5873 */
5874 b0 = gen_mac_multicast(16);
5875 gen_and(b1, b0);
5876
5877 /*
5878 * Now, check for To DS not set, i.e. check
5879 * "!(link[1] & 0x01)".
5880 */
5881 s = gen_load_a(OR_LINK, 1, BPF_B);
5882 b2 = new_block(JMP(BPF_JSET));
5883 b2->s.k = 0x01; /* To DS */
5884 b2->stmts = s;
5885 gen_not(b2);
5886
5887 /*
5888 * If To DS is not set, the DA is at 4.
5889 */
5890 b1 = gen_mac_multicast(4);
5891 gen_and(b2, b1);
5892
5893 /*
5894 * Now OR together the last two checks. That gives
5895 * the complete set of checks for data frames.
5896 */
5897 gen_or(b1, b0);
5898
5899 /*
5900 * Now check for a data frame.
5901 * I.e, check "link[0] & 0x08".
5902 */
5903 s = gen_load_a(OR_LINK, 0, BPF_B);
5904 b1 = new_block(JMP(BPF_JSET));
5905 b1->s.k = 0x08;
5906 b1->stmts = s;
5907
5908 /*
5909 * AND that with the checks done for data frames.
5910 */
5911 gen_and(b1, b0);
5912
5913 /*
5914 * If the high-order bit of the type value is 0, this
5915 * is a management frame.
5916 * I.e, check "!(link[0] & 0x08)".
5917 */
5918 s = gen_load_a(OR_LINK, 0, BPF_B);
5919 b2 = new_block(JMP(BPF_JSET));
5920 b2->s.k = 0x08;
5921 b2->stmts = s;
5922 gen_not(b2);
5923
5924 /*
5925 * For management frames, the DA is at 4.
5926 */
5927 b1 = gen_mac_multicast(4);
5928 gen_and(b2, b1);
5929
5930 /*
5931 * OR that with the checks done for data frames.
5932 * That gives the checks done for management and
5933 * data frames.
5934 */
5935 gen_or(b1, b0);
5936
5937 /*
5938 * If the low-order bit of the type value is 1,
5939 * this is either a control frame or a frame
5940 * with a reserved type, and thus not a
5941 * frame with an SA.
5942 *
5943 * I.e., check "!(link[0] & 0x04)".
5944 */
5945 s = gen_load_a(OR_LINK, 0, BPF_B);
5946 b1 = new_block(JMP(BPF_JSET));
5947 b1->s.k = 0x04;
5948 b1->stmts = s;
5949 gen_not(b1);
5950
5951 /*
5952 * AND that with the checks for data and management
5953 * frames.
5954 */
5955 gen_and(b1, b0);
5956 return b0;
5957 }
5958
5959 if (linktype == DLT_IP_OVER_FC) {
5960 b0 = gen_mac_multicast(2);
5961 return b0;
5962 }
5963
5964 if (linktype == DLT_SUNATM && is_lane) {
5965 /*
5966 * Check that the packet doesn't begin with an
5967 * LE Control marker. (We've already generated
5968 * a test for LANE.)
5969 */
5970 b1 = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS, BPF_H,
5971 0xFF00);
5972 gen_not(b1);
5973
5974 /* ether[off_mac] & 1 != 0 */
5975 b0 = gen_mac_multicast(off_mac);
5976 gen_and(b1, b0);
5977 return b0;
5978 }
5979
5980 /* Link not known to support multicasts */
5981 break;
5982
5983 case Q_IP:
5984 b0 = gen_linktype(ETHERTYPE_IP);
5985 b1 = gen_cmp_ge(OR_NET, 16, BPF_B, (bpf_int32)224);
5986 gen_and(b0, b1);
5987 return b1;
5988
5989 #ifdef INET6
5990 case Q_IPV6:
5991 b0 = gen_linktype(ETHERTYPE_IPV6);
5992 b1 = gen_cmp(OR_NET, 24, BPF_B, (bpf_int32)255);
5993 gen_and(b0, b1);
5994 return b1;
5995 #endif /* INET6 */
5996 }
5997 bpf_error("link-layer multicast filters supported only on ethernet/FDDI/token ring/ARCNET/802.11/ATM LANE/Fibre Channel");
5998 /* NOTREACHED */
5999 }
6000
6001 /*
6002 * generate command for inbound/outbound. It's here so we can
6003 * make it link-type specific. 'dir' = 0 implies "inbound",
6004 * = 1 implies "outbound".
6005 */
6006 struct block *
6007 gen_inbound(dir)
6008 int dir;
6009 {
6010 register struct block *b0;
6011
6012 /*
6013 * Only some data link types support inbound/outbound qualifiers.
6014 */
6015 switch (linktype) {
6016 case DLT_SLIP:
6017 b0 = gen_relation(BPF_JEQ,
6018 gen_load(Q_LINK, gen_loadi(0), 1),
6019 gen_loadi(0),
6020 dir);
6021 break;
6022
6023 case DLT_LINUX_SLL:
6024 if (dir) {
6025 /*
6026 * Match packets sent by this machine.
6027 */
6028 b0 = gen_cmp(OR_LINK, 0, BPF_H, LINUX_SLL_OUTGOING);
6029 } else {
6030 /*
6031 * Match packets sent to this machine.
6032 * (No broadcast or multicast packets, or
6033 * packets sent to some other machine and
6034 * received promiscuously.)
6035 *
6036 * XXX - packets sent to other machines probably
6037 * shouldn't be matched, but what about broadcast
6038 * or multicast packets we received?
6039 */
6040 b0 = gen_cmp(OR_LINK, 0, BPF_H, LINUX_SLL_HOST);
6041 }
6042 break;
6043
6044 case DLT_PFLOG:
6045 b0 = gen_cmp(OR_LINK, offsetof(struct pfloghdr, dir), BPF_B,
6046 (bpf_int32)((dir == 0) ? PF_IN : PF_OUT));
6047 break;
6048
6049 case DLT_PPP_PPPD:
6050 if (dir) {
6051 /* match outgoing packets */
6052 b0 = gen_cmp(OR_LINK, 0, BPF_B, PPP_PPPD_OUT);
6053 } else {
6054 /* match incoming packets */
6055 b0 = gen_cmp(OR_LINK, 0, BPF_B, PPP_PPPD_IN);
6056 }
6057 break;
6058
6059 case DLT_JUNIPER_MFR:
6060 case DLT_JUNIPER_MLFR:
6061 case DLT_JUNIPER_MLPPP:
6062 case DLT_JUNIPER_ATM1:
6063 case DLT_JUNIPER_ATM2:
6064 case DLT_JUNIPER_PPPOE:
6065 case DLT_JUNIPER_PPPOE_ATM:
6066 case DLT_JUNIPER_GGSN:
6067 case DLT_JUNIPER_ES:
6068 case DLT_JUNIPER_MONITOR:
6069 case DLT_JUNIPER_SERVICES:
6070 case DLT_JUNIPER_ETHER:
6071 case DLT_JUNIPER_PPP:
6072 case DLT_JUNIPER_FRELAY:
6073 case DLT_JUNIPER_CHDLC:
6074 /* juniper flags (including direction) are stored
6075 * the byte after the 3-byte magic number */
6076 if (dir) {
6077 /* match outgoing packets */
6078 b0 = gen_mcmp(OR_LINK, 3, BPF_B, 0, 0x01);
6079 } else {
6080 /* match incoming packets */
6081 b0 = gen_mcmp(OR_LINK, 3, BPF_B, 1, 0x01);
6082 }
6083 break;
6084
6085 default:
6086 bpf_error("inbound/outbound not supported on linktype %d",
6087 linktype);
6088 b0 = NULL;
6089 /* NOTREACHED */
6090 }
6091 return (b0);
6092 }
6093
6094 /* PF firewall log matched interface */
6095 struct block *
6096 gen_pf_ifname(const char *ifname)
6097 {
6098 struct block *b0;
6099 u_int len, off;
6100
6101 if (linktype == DLT_PFLOG) {
6102 len = sizeof(((struct pfloghdr *)0)->ifname);
6103 off = offsetof(struct pfloghdr, ifname);
6104 } else {
6105 bpf_error("ifname not supported on linktype 0x%x", linktype);
6106 /* NOTREACHED */
6107 }
6108 if (strlen(ifname) >= len) {
6109 bpf_error("ifname interface names can only be %d characters",
6110 len-1);
6111 /* NOTREACHED */
6112 }
6113 b0 = gen_bcmp(OR_LINK, off, strlen(ifname), (const u_char *)ifname);
6114 return (b0);
6115 }
6116
6117 /* PF firewall log ruleset name */
6118 struct block *
6119 gen_pf_ruleset(char *ruleset)
6120 {
6121 struct block *b0;
6122
6123 if (linktype != DLT_PFLOG) {
6124 bpf_error("ruleset not supported on linktype 0x%x", linktype);
6125 /* NOTREACHED */
6126 }
6127 if (strlen(ruleset) >= sizeof(((struct pfloghdr *)0)->ruleset)) {
6128 bpf_error("ruleset names can only be %ld characters",
6129 (long)(sizeof(((struct pfloghdr *)0)->ruleset) - 1));
6130 /* NOTREACHED */
6131 }
6132 b0 = gen_bcmp(OR_LINK, offsetof(struct pfloghdr, ruleset),
6133 strlen(ruleset), (const u_char *)ruleset);
6134 return (b0);
6135 }
6136
6137 /* PF firewall log rule number */
6138 struct block *
6139 gen_pf_rnr(int rnr)
6140 {
6141 struct block *b0;
6142
6143 if (linktype == DLT_PFLOG) {
6144 b0 = gen_cmp(OR_LINK, offsetof(struct pfloghdr, rulenr), BPF_W,
6145 (bpf_int32)rnr);
6146 } else {
6147 bpf_error("rnr not supported on linktype 0x%x", linktype);
6148 /* NOTREACHED */
6149 }
6150
6151 return (b0);
6152 }
6153
6154 /* PF firewall log sub-rule number */
6155 struct block *
6156 gen_pf_srnr(int srnr)
6157 {
6158 struct block *b0;
6159
6160 if (linktype != DLT_PFLOG) {
6161 bpf_error("srnr not supported on linktype 0x%x", linktype);
6162 /* NOTREACHED */
6163 }
6164
6165 b0 = gen_cmp(OR_LINK, offsetof(struct pfloghdr, subrulenr), BPF_W,
6166 (bpf_int32)srnr);
6167 return (b0);
6168 }
6169
6170 /* PF firewall log reason code */
6171 struct block *
6172 gen_pf_reason(int reason)
6173 {
6174 struct block *b0;
6175
6176 if (linktype == DLT_PFLOG) {
6177 b0 = gen_cmp(OR_LINK, offsetof(struct pfloghdr, reason), BPF_B,
6178 (bpf_int32)reason);
6179 } else {
6180 bpf_error("reason not supported on linktype 0x%x", linktype);
6181 /* NOTREACHED */
6182 }
6183
6184 return (b0);
6185 }
6186
6187 /* PF firewall log action */
6188 struct block *
6189 gen_pf_action(int action)
6190 {
6191 struct block *b0;
6192
6193 if (linktype == DLT_PFLOG) {
6194 b0 = gen_cmp(OR_LINK, offsetof(struct pfloghdr, action), BPF_B,
6195 (bpf_int32)action);
6196 } else {
6197 bpf_error("action not supported on linktype 0x%x", linktype);
6198 /* NOTREACHED */
6199 }
6200
6201 return (b0);
6202 }
6203
6204 struct block *
6205 gen_acode(eaddr, q)
6206 register const u_char *eaddr;
6207 struct qual q;
6208 {
6209 if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK) {
6210 if (linktype == DLT_ARCNET || linktype == DLT_ARCNET_LINUX)
6211 return gen_ahostop(eaddr, (int)q.dir);
6212 }
6213 bpf_error("ARCnet address used in non-arc expression");
6214 /* NOTREACHED */
6215 }
6216
6217 static struct block *
6218 gen_ahostop(eaddr, dir)
6219 register const u_char *eaddr;
6220 register int dir;
6221 {
6222 register struct block *b0, *b1;
6223
6224 switch (dir) {
6225 /* src comes first, different from Ethernet */
6226 case Q_SRC:
6227 return gen_bcmp(OR_LINK, 0, 1, eaddr);
6228
6229 case Q_DST:
6230 return gen_bcmp(OR_LINK, 1, 1, eaddr);
6231
6232 case Q_AND:
6233 b0 = gen_ahostop(eaddr, Q_SRC);
6234 b1 = gen_ahostop(eaddr, Q_DST);
6235 gen_and(b0, b1);
6236 return b1;
6237
6238 case Q_DEFAULT:
6239 case Q_OR:
6240 b0 = gen_ahostop(eaddr, Q_SRC);
6241 b1 = gen_ahostop(eaddr, Q_DST);
6242 gen_or(b0, b1);
6243 return b1;
6244 }
6245 abort();
6246 /* NOTREACHED */
6247 }
6248
6249 /*
6250 * support IEEE 802.1Q VLAN trunk over ethernet
6251 */
6252 struct block *
6253 gen_vlan(vlan_num)
6254 int vlan_num;
6255 {
6256 struct block *b0, *b1;
6257
6258 /* can't check for VLAN-encapsulated packets inside MPLS */
6259 if (label_stack_depth > 0)
6260 bpf_error("no VLAN match after MPLS");
6261
6262 /*
6263 * Change the offsets to point to the type and data fields within
6264 * the VLAN packet. Just increment the offsets, so that we
6265 * can support a hierarchy, e.g. "vlan 300 && vlan 200" to
6266 * capture VLAN 200 encapsulated within VLAN 100.
6267 *
6268 * XXX - this is a bit of a kludge. If we were to split the
6269 * compiler into a parser that parses an expression and
6270 * generates an expression tree, and a code generator that
6271 * takes an expression tree (which could come from our
6272 * parser or from some other parser) and generates BPF code,
6273 * we could perhaps make the offsets parameters of routines
6274 * and, in the handler for an "AND" node, pass to subnodes
6275 * other than the VLAN node the adjusted offsets.
6276 *
6277 * This would mean that "vlan" would, instead of changing the
6278 * behavior of *all* tests after it, change only the behavior
6279 * of tests ANDed with it. That would change the documented
6280 * semantics of "vlan", which might break some expressions.
6281 * However, it would mean that "(vlan and ip) or ip" would check
6282 * both for VLAN-encapsulated IP and IP-over-Ethernet, rather than
6283 * checking only for VLAN-encapsulated IP, so that could still
6284 * be considered worth doing; it wouldn't break expressions
6285 * that are of the form "vlan and ..." or "vlan N and ...",
6286 * which I suspect are the most common expressions involving
6287 * "vlan". "vlan or ..." doesn't necessarily do what the user
6288 * would really want, now, as all the "or ..." tests would
6289 * be done assuming a VLAN, even though the "or" could be viewed
6290 * as meaning "or, if this isn't a VLAN packet...".
6291 */
6292 orig_linktype = off_linktype; /* save original values */
6293 orig_nl = off_nl;
6294
6295 switch (linktype) {
6296
6297 case DLT_EN10MB:
6298 off_linktype += 4;
6299 off_nl_nosnap += 4;
6300 off_nl += 4;
6301 break;
6302
6303 default:
6304 bpf_error("no VLAN support for data link type %d",
6305 linktype);
6306 /*NOTREACHED*/
6307 }
6308
6309 /* check for VLAN */
6310 b0 = gen_cmp(OR_LINK, orig_linktype, BPF_H, (bpf_int32)ETHERTYPE_8021Q);
6311
6312 /* If a specific VLAN is requested, check VLAN id */
6313 if (vlan_num >= 0) {
6314 b1 = gen_mcmp(OR_LINK, orig_nl, BPF_H, (bpf_int32)vlan_num,
6315 0x0fff);
6316 gen_and(b0, b1);
6317 b0 = b1;
6318 }
6319
6320 return (b0);
6321 }
6322
6323 /*
6324 * support for MPLS
6325 */
6326 struct block *
6327 gen_mpls(label_num)
6328 int label_num;
6329 {
6330 struct block *b0,*b1;
6331
6332 /*
6333 * Change the offsets to point to the type and data fields within
6334 * the MPLS packet. Just increment the offsets, so that we
6335 * can support a hierarchy, e.g. "mpls 100000 && mpls 1024" to
6336 * capture packets with an outer label of 100000 and an inner
6337 * label of 1024.
6338 *
6339 * XXX - this is a bit of a kludge. See comments in gen_vlan().
6340 */
6341 orig_nl = off_nl;
6342
6343 if (label_stack_depth > 0) {
6344 /* just match the bottom-of-stack bit clear */
6345 b0 = gen_mcmp(OR_LINK, orig_nl-2, BPF_B, 0, 0x01);
6346 } else {
6347 /*
6348 * Indicate that we're checking MPLS-encapsulated headers,
6349 * to make sure higher level code generators don't try to
6350 * match against IP-related protocols such as Q_ARP, Q_RARP
6351 * etc.
6352 */
6353 switch (linktype) {
6354
6355 case DLT_C_HDLC: /* fall through */
6356 case DLT_EN10MB:
6357 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H,
6358 (bpf_int32)ETHERTYPE_MPLS);
6359 break;
6360
6361 case DLT_PPP:
6362 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H,
6363 (bpf_int32)PPP_MPLS_UCAST);
6364 break;
6365
6366 /* FIXME add other DLT_s ...
6367 * for Frame-Relay/and ATM this may get messy due to SNAP headers
6368 * leave it for now */
6369
6370 default:
6371 bpf_error("no MPLS support for data link type %d",
6372 linktype);
6373 b0 = NULL;
6374 /*NOTREACHED*/
6375 break;
6376 }
6377 }
6378
6379 /* If a specific MPLS label is requested, check it */
6380 if (label_num >= 0) {
6381 label_num = label_num << 12; /* label is shifted 12 bits on the wire */
6382 b1 = gen_mcmp(OR_LINK, orig_nl, BPF_W, (bpf_int32)label_num,
6383 0xfffff000); /* only compare the first 20 bits */
6384 gen_and(b0, b1);
6385 b0 = b1;
6386 }
6387
6388 off_nl_nosnap += 4;
6389 off_nl += 4;
6390 label_stack_depth++;
6391 return (b0);
6392 }
6393
6394 /*
6395 * Support PPPOE discovery and session.
6396 */
6397 struct block *
6398 gen_pppoed()
6399 {
6400 /* check for PPPoE discovery */
6401 return gen_linktype((bpf_int32)ETHERTYPE_PPPOED);
6402 }
6403
6404 struct block *
6405 gen_pppoes()
6406 {
6407 struct block *b0;
6408
6409 /*
6410 * Test against the PPPoE session link-layer type.
6411 */
6412 b0 = gen_linktype((bpf_int32)ETHERTYPE_PPPOES);
6413
6414 /*
6415 * Change the offsets to point to the type and data fields within
6416 * the PPP packet.
6417 *
6418 * XXX - this is a bit of a kludge. If we were to split the
6419 * compiler into a parser that parses an expression and
6420 * generates an expression tree, and a code generator that
6421 * takes an expression tree (which could come from our
6422 * parser or from some other parser) and generates BPF code,
6423 * we could perhaps make the offsets parameters of routines
6424 * and, in the handler for an "AND" node, pass to subnodes
6425 * other than the PPPoE node the adjusted offsets.
6426 *
6427 * This would mean that "pppoes" would, instead of changing the
6428 * behavior of *all* tests after it, change only the behavior
6429 * of tests ANDed with it. That would change the documented
6430 * semantics of "pppoes", which might break some expressions.
6431 * However, it would mean that "(pppoes and ip) or ip" would check
6432 * both for VLAN-encapsulated IP and IP-over-Ethernet, rather than
6433 * checking only for VLAN-encapsulated IP, so that could still
6434 * be considered worth doing; it wouldn't break expressions
6435 * that are of the form "pppoes and ..." which I suspect are the
6436 * most common expressions involving "pppoes". "pppoes or ..."
6437 * doesn't necessarily do what the user would really want, now,
6438 * as all the "or ..." tests would be done assuming PPPoE, even
6439 * though the "or" could be viewed as meaning "or, if this isn't
6440 * a PPPoE packet...".
6441 */
6442 orig_linktype = off_linktype; /* save original values */
6443 orig_nl = off_nl;
6444
6445 /*
6446 * The "network-layer" protocol is PPPoE, which has a 6-byte
6447 * PPPoE header, followed by PPP payload, so we set the
6448 * offsets to the network layer offset plus 6 bytes for
6449 * the PPPoE header plus the values appropriate for PPP when
6450 * encapsulated in Ethernet (which means there's no HDLC
6451 * encapsulation).
6452 */
6453 off_linktype = orig_nl + 6;
6454 off_nl = orig_nl + 6 + 2;
6455 off_nl_nosnap = orig_nl + 6 + 2;
6456
6457 /*
6458 * Set the link-layer type to PPP, as all subsequent tests will
6459 * be on the encapsulated PPP header.
6460 */
6461 linktype = DLT_PPP;
6462
6463 return b0;
6464 }
6465
6466 struct block *
6467 gen_atmfield_code(atmfield, jvalue, jtype, reverse)
6468 int atmfield;
6469 bpf_int32 jvalue;
6470 bpf_u_int32 jtype;
6471 int reverse;
6472 {
6473 struct block *b0;
6474
6475 switch (atmfield) {
6476
6477 case A_VPI:
6478 if (!is_atm)
6479 bpf_error("'vpi' supported only on raw ATM");
6480 if (off_vpi == (u_int)-1)
6481 abort();
6482 b0 = gen_ncmp(OR_LINK, off_vpi, BPF_B, 0xffffffff, jtype,
6483 reverse, jvalue);
6484 break;
6485
6486 case A_VCI:
6487 if (!is_atm)
6488 bpf_error("'vci' supported only on raw ATM");
6489 if (off_vci == (u_int)-1)
6490 abort();
6491 b0 = gen_ncmp(OR_LINK, off_vci, BPF_H, 0xffffffff, jtype,
6492 reverse, jvalue);
6493 break;
6494
6495 case A_PROTOTYPE:
6496 if (off_proto == (u_int)-1)
6497 abort(); /* XXX - this isn't on FreeBSD */
6498 b0 = gen_ncmp(OR_LINK, off_proto, BPF_B, 0x0f, jtype,
6499 reverse, jvalue);
6500 break;
6501
6502 case A_MSGTYPE:
6503 if (off_payload == (u_int)-1)
6504 abort();
6505 b0 = gen_ncmp(OR_LINK, off_payload + MSG_TYPE_POS, BPF_B,
6506 0xffffffff, jtype, reverse, jvalue);
6507 break;
6508
6509 case A_CALLREFTYPE:
6510 if (!is_atm)
6511 bpf_error("'callref' supported only on raw ATM");
6512 if (off_proto == (u_int)-1)
6513 abort();
6514 b0 = gen_ncmp(OR_LINK, off_proto, BPF_B, 0xffffffff,
6515 jtype, reverse, jvalue);
6516 break;
6517
6518 default:
6519 abort();
6520 }
6521 return b0;
6522 }
6523
6524 struct block *
6525 gen_atmtype_abbrev(type)
6526 int type;
6527 {
6528 struct block *b0, *b1;
6529
6530 switch (type) {
6531
6532 case A_METAC:
6533 /* Get all packets in Meta signalling Circuit */
6534 if (!is_atm)
6535 bpf_error("'metac' supported only on raw ATM");
6536 b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0);
6537 b1 = gen_atmfield_code(A_VCI, 1, BPF_JEQ, 0);
6538 gen_and(b0, b1);
6539 break;
6540
6541 case A_BCC:
6542 /* Get all packets in Broadcast Circuit*/
6543 if (!is_atm)
6544 bpf_error("'bcc' supported only on raw ATM");
6545 b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0);
6546 b1 = gen_atmfield_code(A_VCI, 2, BPF_JEQ, 0);
6547 gen_and(b0, b1);
6548 break;
6549
6550 case A_OAMF4SC:
6551 /* Get all cells in Segment OAM F4 circuit*/
6552 if (!is_atm)
6553 bpf_error("'oam4sc' supported only on raw ATM");
6554 b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0);
6555 b1 = gen_atmfield_code(A_VCI, 3, BPF_JEQ, 0);
6556 gen_and(b0, b1);
6557 break;
6558
6559 case A_OAMF4EC:
6560 /* Get all cells in End-to-End OAM F4 Circuit*/
6561 if (!is_atm)
6562 bpf_error("'oam4ec' supported only on raw ATM");
6563 b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0);
6564 b1 = gen_atmfield_code(A_VCI, 4, BPF_JEQ, 0);
6565 gen_and(b0, b1);
6566 break;
6567
6568 case A_SC:
6569 /* Get all packets in connection Signalling Circuit */
6570 if (!is_atm)
6571 bpf_error("'sc' supported only on raw ATM");
6572 b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0);
6573 b1 = gen_atmfield_code(A_VCI, 5, BPF_JEQ, 0);
6574 gen_and(b0, b1);
6575 break;
6576
6577 case A_ILMIC:
6578 /* Get all packets in ILMI Circuit */
6579 if (!is_atm)
6580 bpf_error("'ilmic' supported only on raw ATM");
6581 b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0);
6582 b1 = gen_atmfield_code(A_VCI, 16, BPF_JEQ, 0);
6583 gen_and(b0, b1);
6584 break;
6585
6586 case A_LANE:
6587 /* Get all LANE packets */
6588 if (!is_atm)
6589 bpf_error("'lane' supported only on raw ATM");
6590 b1 = gen_atmfield_code(A_PROTOTYPE, PT_LANE, BPF_JEQ, 0);
6591
6592 /*
6593 * Arrange that all subsequent tests assume LANE
6594 * rather than LLC-encapsulated packets, and set
6595 * the offsets appropriately for LANE-encapsulated
6596 * Ethernet.
6597 *
6598 * "off_mac" is the offset of the Ethernet header,
6599 * which is 2 bytes past the ATM pseudo-header
6600 * (skipping the pseudo-header and 2-byte LE Client
6601 * field). The other offsets are Ethernet offsets
6602 * relative to "off_mac".
6603 */
6604 is_lane = 1;
6605 off_mac = off_payload + 2; /* MAC header */
6606 off_linktype = off_mac + 12;
6607 off_nl = off_mac + 14; /* Ethernet II */
6608 off_nl_nosnap = off_mac + 17; /* 802.3+802.2 */
6609 break;
6610
6611 case A_LLC:
6612 /* Get all LLC-encapsulated packets */
6613 if (!is_atm)
6614 bpf_error("'llc' supported only on raw ATM");
6615 b1 = gen_atmfield_code(A_PROTOTYPE, PT_LLC, BPF_JEQ, 0);
6616 is_lane = 0;
6617 break;
6618
6619 default:
6620 abort();
6621 }
6622 return b1;
6623 }
6624
6625 struct block *
6626 gen_mtp3field_code(mtp3field, jvalue, jtype, reverse)
6627 int mtp3field;
6628 bpf_u_int32 jvalue;
6629 bpf_u_int32 jtype;
6630 int reverse;
6631 {
6632 struct block *b0;
6633 bpf_u_int32 val1 , val2 , val3;
6634
6635 switch (mtp3field) {
6636
6637 case M_SIO:
6638 if (off_sio == (u_int)-1)
6639 bpf_error("'sio' supported only on SS7");
6640 /* sio coded on 1 byte so max value 255 */
6641 if(jvalue > 255)
6642 bpf_error("sio value %u too big; max value = 255",
6643 jvalue);
6644 b0 = gen_ncmp(OR_PACKET, off_sio, BPF_B, 0xffffffff,
6645 (u_int)jtype, reverse, (u_int)jvalue);
6646 break;
6647
6648 case M_OPC:
6649 if (off_opc == (u_int)-1)
6650 bpf_error("'opc' supported only on SS7");
6651 /* opc coded on 14 bits so max value 16383 */
6652 if (jvalue > 16383)
6653 bpf_error("opc value %u too big; max value = 16383",
6654 jvalue);
6655 /* the following instructions are made to convert jvalue
6656 * to the form used to write opc in an ss7 message*/
6657 val1 = jvalue & 0x00003c00;
6658 val1 = val1 >>10;
6659 val2 = jvalue & 0x000003fc;
6660 val2 = val2 <<6;
6661 val3 = jvalue & 0x00000003;
6662 val3 = val3 <<22;
6663 jvalue = val1 + val2 + val3;
6664 b0 = gen_ncmp(OR_PACKET, off_opc, BPF_W, 0x00c0ff0f,
6665 (u_int)jtype, reverse, (u_int)jvalue);
6666 break;
6667
6668 case M_DPC:
6669 if (off_dpc == (u_int)-1)
6670 bpf_error("'dpc' supported only on SS7");
6671 /* dpc coded on 14 bits so max value 16383 */
6672 if (jvalue > 16383)
6673 bpf_error("dpc value %u too big; max value = 16383",
6674 jvalue);
6675 /* the following instructions are made to convert jvalue
6676 * to the forme used to write dpc in an ss7 message*/
6677 val1 = jvalue & 0x000000ff;
6678 val1 = val1 << 24;
6679 val2 = jvalue & 0x00003f00;
6680 val2 = val2 << 8;
6681 jvalue = val1 + val2;
6682 b0 = gen_ncmp(OR_PACKET, off_dpc, BPF_W, 0xff3f0000,
6683 (u_int)jtype, reverse, (u_int)jvalue);
6684 break;
6685
6686 case M_SLS:
6687 if (off_sls == (u_int)-1)
6688 bpf_error("'sls' supported only on SS7");
6689 /* sls coded on 4 bits so max value 15 */
6690 if (jvalue > 15)
6691 bpf_error("sls value %u too big; max value = 15",
6692 jvalue);
6693 /* the following instruction is made to convert jvalue
6694 * to the forme used to write sls in an ss7 message*/
6695 jvalue = jvalue << 4;
6696 b0 = gen_ncmp(OR_PACKET, off_sls, BPF_B, 0xf0,
6697 (u_int)jtype,reverse, (u_int)jvalue);
6698 break;
6699
6700 default:
6701 abort();
6702 }
6703 return b0;
6704 }
6705
6706 static struct block *
6707 gen_msg_abbrev(type)
6708 int type;
6709 {
6710 struct block *b1;
6711
6712 /*
6713 * Q.2931 signalling protocol messages for handling virtual circuits
6714 * establishment and teardown
6715 */
6716 switch (type) {
6717
6718 case A_SETUP:
6719 b1 = gen_atmfield_code(A_MSGTYPE, SETUP, BPF_JEQ, 0);
6720 break;
6721
6722 case A_CALLPROCEED:
6723 b1 = gen_atmfield_code(A_MSGTYPE, CALL_PROCEED, BPF_JEQ, 0);
6724 break;
6725
6726 case A_CONNECT:
6727 b1 = gen_atmfield_code(A_MSGTYPE, CONNECT, BPF_JEQ, 0);
6728 break;
6729
6730 case A_CONNECTACK:
6731 b1 = gen_atmfield_code(A_MSGTYPE, CONNECT_ACK, BPF_JEQ, 0);
6732 break;
6733
6734 case A_RELEASE:
6735 b1 = gen_atmfield_code(A_MSGTYPE, RELEASE, BPF_JEQ, 0);
6736 break;
6737
6738 case A_RELEASE_DONE:
6739 b1 = gen_atmfield_code(A_MSGTYPE, RELEASE_DONE, BPF_JEQ, 0);
6740 break;
6741
6742 default:
6743 abort();
6744 }
6745 return b1;
6746 }
6747
6748 struct block *
6749 gen_atmmulti_abbrev(type)
6750 int type;
6751 {
6752 struct block *b0, *b1;
6753
6754 switch (type) {
6755
6756 case A_OAM:
6757 if (!is_atm)
6758 bpf_error("'oam' supported only on raw ATM");
6759 b1 = gen_atmmulti_abbrev(A_OAMF4);
6760 break;
6761
6762 case A_OAMF4:
6763 if (!is_atm)
6764 bpf_error("'oamf4' supported only on raw ATM");
6765 /* OAM F4 type */
6766 b0 = gen_atmfield_code(A_VCI, 3, BPF_JEQ, 0);
6767 b1 = gen_atmfield_code(A_VCI, 4, BPF_JEQ, 0);
6768 gen_or(b0, b1);
6769 b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0);
6770 gen_and(b0, b1);
6771 break;
6772
6773 case A_CONNECTMSG:
6774 /*
6775 * Get Q.2931 signalling messages for switched
6776 * virtual connection
6777 */
6778 if (!is_atm)
6779 bpf_error("'connectmsg' supported only on raw ATM");
6780 b0 = gen_msg_abbrev(A_SETUP);
6781 b1 = gen_msg_abbrev(A_CALLPROCEED);
6782 gen_or(b0, b1);
6783 b0 = gen_msg_abbrev(A_CONNECT);
6784 gen_or(b0, b1);
6785 b0 = gen_msg_abbrev(A_CONNECTACK);
6786 gen_or(b0, b1);
6787 b0 = gen_msg_abbrev(A_RELEASE);
6788 gen_or(b0, b1);
6789 b0 = gen_msg_abbrev(A_RELEASE_DONE);
6790 gen_or(b0, b1);
6791 b0 = gen_atmtype_abbrev(A_SC);
6792 gen_and(b0, b1);
6793 break;
6794
6795 case A_METACONNECT:
6796 if (!is_atm)
6797 bpf_error("'metaconnect' supported only on raw ATM");
6798 b0 = gen_msg_abbrev(A_SETUP);
6799 b1 = gen_msg_abbrev(A_CALLPROCEED);
6800 gen_or(b0, b1);
6801 b0 = gen_msg_abbrev(A_CONNECT);
6802 gen_or(b0, b1);
6803 b0 = gen_msg_abbrev(A_RELEASE);
6804 gen_or(b0, b1);
6805 b0 = gen_msg_abbrev(A_RELEASE_DONE);
6806 gen_or(b0, b1);
6807 b0 = gen_atmtype_abbrev(A_METAC);
6808 gen_and(b0, b1);
6809 break;
6810
6811 default:
6812 abort();
6813 }
6814 return b1;
6815 }
[mirror] the LIBpcap interface to various kernel packet capture mechanism