Update files for libpcap-1.2.1 import.
[dragonfly.git] / contrib / libpcap / gencode.c
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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
23static const char rcsid[] _U_ =
a85e14b0 24 "@(#) $Header: /tcpdump/master/libpcap/gencode.c,v 1.309 2008-12-23 20:13:29 guy Exp $ (LBL)";
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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 */
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34#if HAVE_INTTYPES_H
35#include <inttypes.h>
36#elif HAVE_STDINT_H
37#include <stdint.h>
38#endif
39#ifdef HAVE_SYS_BITYPES_H
40#include <sys/bitypes.h>
41#endif
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42#include <sys/types.h>
43#include <sys/socket.h>
44#endif /* WIN32 */
45
46/*
47 * XXX - why was this included even on UNIX?
48 */
49#ifdef __MINGW32__
a85e14b0 50#include "ip6_misc.h"
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51#endif
52
53#ifndef WIN32
54
55#ifdef __NetBSD__
56#include <sys/param.h>
57#endif
58
59#include <netinet/in.h>
a85e14b0 60#include <arpa/inet.h>
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61
62#endif /* WIN32 */
63
64#include <stdlib.h>
65#include <string.h>
66#include <memory.h>
67#include <setjmp.h>
68#include <stdarg.h>
69
70#ifdef MSDOS
71#include "pcap-dos.h"
72#endif
73
74#include "pcap-int.h"
75
76#include "ethertype.h"
77#include "nlpid.h"
78#include "llc.h"
79#include "gencode.h"
73e63d40 80#include "ieee80211.h"
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81#include "atmuni31.h"
82#include "sunatmpos.h"
83#include "ppp.h"
de0d3203 84#include "pcap/sll.h"
a85e14b0 85#include "pcap/ipnet.h"
23fa89e6 86#include "arcnet.h"
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87#ifdef HAVE_NET_PFVAR_H
88#include <sys/socket.h>
89#include <net/if.h>
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90#include <net/pf/pfvar.h>
91#include <net/pf/if_pflog.h>
084fe320 92#endif
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93#ifndef offsetof
94#define offsetof(s, e) ((size_t)&((s *)0)->e)
95#endif
96#ifdef INET6
97#ifndef WIN32
98#include <netdb.h> /* for "struct addrinfo" */
99#endif /* WIN32 */
100#endif /*INET6*/
de0d3203 101#include <pcap/namedb.h>
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102
103#define ETHERMTU 1500
104
105#ifndef IPPROTO_SCTP
106#define IPPROTO_SCTP 132
107#endif
108
109#ifdef HAVE_OS_PROTO_H
110#include "os-proto.h"
111#endif
112
113#define JMP(c) ((c)|BPF_JMP|BPF_K)
114
115/* Locals */
116static jmp_buf top_ctx;
117static pcap_t *bpf_pcap;
118
119/* Hack for updating VLAN, MPLS, and PPPoE offsets. */
de0d3203 120#ifdef WIN32
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121static u_int orig_linktype = (u_int)-1, orig_nl = (u_int)-1, label_stack_depth = (u_int)-1;
122#else
23fa89e6 123static u_int orig_linktype = -1U, orig_nl = -1U, label_stack_depth = -1U;
dfcad8d8 124#endif
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125
126/* XXX */
127#ifdef PCAP_FDDIPAD
128static int pcap_fddipad;
129#endif
130
131/* VARARGS */
132void
133bpf_error(const char *fmt, ...)
134{
135 va_list ap;
136
137 va_start(ap, fmt);
138 if (bpf_pcap != NULL)
139 (void)vsnprintf(pcap_geterr(bpf_pcap), PCAP_ERRBUF_SIZE,
140 fmt, ap);
141 va_end(ap);
142 longjmp(top_ctx, 1);
143 /* NOTREACHED */
144}
145
146static void init_linktype(pcap_t *);
147
de0d3203 148static void init_regs(void);
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149static int alloc_reg(void);
150static void free_reg(int);
151
152static struct block *root;
153
154/*
155 * Value passed to gen_load_a() to indicate what the offset argument
156 * is relative to.
157 */
158enum e_offrel {
159 OR_PACKET, /* relative to the beginning of the packet */
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160 OR_LINK, /* relative to the beginning of the link-layer header */
161 OR_MACPL, /* relative to the end of the MAC-layer header */
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162 OR_NET, /* relative to the network-layer header */
163 OR_NET_NOSNAP, /* relative to the network-layer header, with no SNAP header at the link layer */
164 OR_TRAN_IPV4, /* relative to the transport-layer header, with IPv4 network layer */
165 OR_TRAN_IPV6 /* relative to the transport-layer header, with IPv6 network layer */
166};
167
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168#ifdef INET6
169/*
170 * As errors are handled by a longjmp, anything allocated must be freed
171 * in the longjmp handler, so it must be reachable from that handler.
172 * One thing that's allocated is the result of pcap_nametoaddrinfo();
173 * it must be freed with freeaddrinfo(). This variable points to any
174 * addrinfo structure that would need to be freed.
175 */
176static struct addrinfo *ai;
177#endif
178
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179/*
180 * We divy out chunks of memory rather than call malloc each time so
181 * we don't have to worry about leaking memory. It's probably
182 * not a big deal if all this memory was wasted but if this ever
183 * goes into a library that would probably not be a good idea.
184 *
185 * XXX - this *is* in a library....
186 */
187#define NCHUNKS 16
188#define CHUNK0SIZE 1024
189struct chunk {
190 u_int n_left;
191 void *m;
192};
193
194static struct chunk chunks[NCHUNKS];
195static int cur_chunk;
196
197static void *newchunk(u_int);
198static void freechunks(void);
199static inline struct block *new_block(int);
200static inline struct slist *new_stmt(int);
201static struct block *gen_retblk(int);
202static inline void syntax(void);
203
204static void backpatch(struct block *, struct block *);
205static void merge(struct block *, struct block *);
206static struct block *gen_cmp(enum e_offrel, u_int, u_int, bpf_int32);
207static struct block *gen_cmp_gt(enum e_offrel, u_int, u_int, bpf_int32);
208static struct block *gen_cmp_ge(enum e_offrel, u_int, u_int, bpf_int32);
209static struct block *gen_cmp_lt(enum e_offrel, u_int, u_int, bpf_int32);
210static struct block *gen_cmp_le(enum e_offrel, u_int, u_int, bpf_int32);
211static struct block *gen_mcmp(enum e_offrel, u_int, u_int, bpf_int32,
212 bpf_u_int32);
213static struct block *gen_bcmp(enum e_offrel, u_int, u_int, const u_char *);
214static struct block *gen_ncmp(enum e_offrel, bpf_u_int32, bpf_u_int32,
215 bpf_u_int32, bpf_u_int32, int, bpf_int32);
216static struct slist *gen_load_llrel(u_int, u_int);
de0d3203 217static struct slist *gen_load_macplrel(u_int, u_int);
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218static struct slist *gen_load_a(enum e_offrel, u_int, u_int);
219static struct slist *gen_loadx_iphdrlen(void);
220static struct block *gen_uncond(int);
221static inline struct block *gen_true(void);
222static inline struct block *gen_false(void);
223static struct block *gen_ether_linktype(int);
a85e14b0 224static struct block *gen_ipnet_linktype(int);
23fa89e6 225static struct block *gen_linux_sll_linktype(int);
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226static struct slist *gen_load_prism_llprefixlen(void);
227static struct slist *gen_load_avs_llprefixlen(void);
228static struct slist *gen_load_radiotap_llprefixlen(void);
229static struct slist *gen_load_ppi_llprefixlen(void);
230static void insert_compute_vloffsets(struct block *);
23fa89e6 231static struct slist *gen_llprefixlen(void);
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232static struct slist *gen_off_macpl(void);
233static int ethertype_to_ppptype(int);
23fa89e6 234static struct block *gen_linktype(int);
de0d3203 235static struct block *gen_snap(bpf_u_int32, bpf_u_int32);
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236static struct block *gen_llc_linktype(int);
237static struct block *gen_hostop(bpf_u_int32, bpf_u_int32, int, int, u_int, u_int);
238#ifdef INET6
239static struct block *gen_hostop6(struct in6_addr *, struct in6_addr *, int, int, u_int, u_int);
240#endif
241static struct block *gen_ahostop(const u_char *, int);
242static struct block *gen_ehostop(const u_char *, int);
243static struct block *gen_fhostop(const u_char *, int);
244static struct block *gen_thostop(const u_char *, int);
245static struct block *gen_wlanhostop(const u_char *, int);
246static struct block *gen_ipfchostop(const u_char *, int);
247static struct block *gen_dnhostop(bpf_u_int32, int);
248static struct block *gen_mpls_linktype(int);
249static struct block *gen_host(bpf_u_int32, bpf_u_int32, int, int, int);
250#ifdef INET6
251static struct block *gen_host6(struct in6_addr *, struct in6_addr *, int, int, int);
252#endif
253#ifndef INET6
254static struct block *gen_gateway(const u_char *, bpf_u_int32 **, int, int);
255#endif
256static struct block *gen_ipfrag(void);
257static struct block *gen_portatom(int, bpf_int32);
258static struct block *gen_portrangeatom(int, bpf_int32, bpf_int32);
259#ifdef INET6
260static struct block *gen_portatom6(int, bpf_int32);
261static struct block *gen_portrangeatom6(int, bpf_int32, bpf_int32);
262#endif
263struct block *gen_portop(int, int, int);
264static struct block *gen_port(int, int, int);
265struct block *gen_portrangeop(int, int, int, int);
266static struct block *gen_portrange(int, int, int, int);
267#ifdef INET6
268struct block *gen_portop6(int, int, int);
269static struct block *gen_port6(int, int, int);
270struct block *gen_portrangeop6(int, int, int, int);
271static struct block *gen_portrange6(int, int, int, int);
272#endif
273static int lookup_proto(const char *, int);
274static struct block *gen_protochain(int, int, int);
275static struct block *gen_proto(int, int, int);
276static struct slist *xfer_to_x(struct arth *);
277static struct slist *xfer_to_a(struct arth *);
278static struct block *gen_mac_multicast(int);
279static struct block *gen_len(int, int);
de0d3203 280static struct block *gen_check_802_11_data_frame(void);
23fa89e6 281
dfcad8d8 282static struct block *gen_ppi_dlt_check(void);
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283static struct block *gen_msg_abbrev(int type);
284
285static void *
286newchunk(n)
287 u_int n;
288{
289 struct chunk *cp;
290 int k;
291 size_t size;
292
293#ifndef __NetBSD__
294 /* XXX Round up to nearest long. */
295 n = (n + sizeof(long) - 1) & ~(sizeof(long) - 1);
296#else
297 /* XXX Round up to structure boundary. */
298 n = ALIGN(n);
299#endif
300
301 cp = &chunks[cur_chunk];
302 if (n > cp->n_left) {
303 ++cp, k = ++cur_chunk;
304 if (k >= NCHUNKS)
305 bpf_error("out of memory");
306 size = CHUNK0SIZE << k;
307 cp->m = (void *)malloc(size);
308 if (cp->m == NULL)
309 bpf_error("out of memory");
310 memset((char *)cp->m, 0, size);
311 cp->n_left = size;
312 if (n > size)
313 bpf_error("out of memory");
314 }
315 cp->n_left -= n;
316 return (void *)((char *)cp->m + cp->n_left);
317}
318
319static void
320freechunks()
321{
322 int i;
323
324 cur_chunk = 0;
325 for (i = 0; i < NCHUNKS; ++i)
326 if (chunks[i].m != NULL) {
327 free(chunks[i].m);
328 chunks[i].m = NULL;
329 }
330}
331
332/*
333 * A strdup whose allocations are freed after code generation is over.
334 */
335char *
336sdup(s)
337 register const char *s;
338{
339 int n = strlen(s) + 1;
340 char *cp = newchunk(n);
341
342 strlcpy(cp, s, n);
343 return (cp);
344}
345
346static inline struct block *
347new_block(code)
348 int code;
349{
350 struct block *p;
351
352 p = (struct block *)newchunk(sizeof(*p));
353 p->s.code = code;
354 p->head = p;
355
356 return p;
357}
358
359static inline struct slist *
360new_stmt(code)
361 int code;
362{
363 struct slist *p;
364
365 p = (struct slist *)newchunk(sizeof(*p));
366 p->s.code = code;
367
368 return p;
369}
370
371static struct block *
372gen_retblk(v)
373 int v;
374{
375 struct block *b = new_block(BPF_RET|BPF_K);
376
377 b->s.k = v;
378 return b;
379}
380
381static inline void
382syntax()
383{
384 bpf_error("syntax error in filter expression");
385}
386
387static bpf_u_int32 netmask;
388static int snaplen;
389int no_optimize;
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390#ifdef WIN32
391static int
392pcap_compile_unsafe(pcap_t *p, struct bpf_program *program,
393 const char *buf, int optimize, bpf_u_int32 mask);
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394
395int
396pcap_compile(pcap_t *p, struct bpf_program *program,
dfcad8d8 397 const char *buf, int optimize, bpf_u_int32 mask)
23fa89e6 398{
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399 int result;
400
401 EnterCriticalSection(&g_PcapCompileCriticalSection);
402
403 result = pcap_compile_unsafe(p, program, buf, optimize, mask);
404
405 LeaveCriticalSection(&g_PcapCompileCriticalSection);
406
407 return result;
408}
409
410static int
411pcap_compile_unsafe(pcap_t *p, struct bpf_program *program,
412 const char *buf, int optimize, bpf_u_int32 mask)
413#else /* WIN32 */
414int
415pcap_compile(pcap_t *p, struct bpf_program *program,
416 const char *buf, int optimize, bpf_u_int32 mask)
417#endif /* WIN32 */
418{
23fa89e6 419 extern int n_errors;
dfcad8d8 420 const char * volatile xbuf = buf;
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421 int len;
422
423 no_optimize = 0;
424 n_errors = 0;
425 root = NULL;
426 bpf_pcap = p;
de0d3203 427 init_regs();
23fa89e6 428 if (setjmp(top_ctx)) {
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429#ifdef INET6
430 if (ai != NULL) {
431 freeaddrinfo(ai);
432 ai = NULL;
433 }
434#endif
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435 lex_cleanup();
436 freechunks();
437 return (-1);
438 }
439
440 netmask = mask;
441
442 snaplen = pcap_snapshot(p);
443 if (snaplen == 0) {
444 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
445 "snaplen of 0 rejects all packets");
446 return -1;
447 }
448
dfcad8d8 449 lex_init(xbuf ? xbuf : "");
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450 init_linktype(p);
451 (void)pcap_parse();
452
453 if (n_errors)
454 syntax();
455
456 if (root == NULL)
457 root = gen_retblk(snaplen);
458
459 if (optimize && !no_optimize) {
460 bpf_optimize(&root);
461 if (root == NULL ||
462 (root->s.code == (BPF_RET|BPF_K) && root->s.k == 0))
463 bpf_error("expression rejects all packets");
464 }
465 program->bf_insns = icode_to_fcode(root, &len);
466 program->bf_len = len;
467
468 lex_cleanup();
469 freechunks();
470 return (0);
471}
472
473/*
474 * entry point for using the compiler with no pcap open
475 * pass in all the stuff that is needed explicitly instead.
476 */
477int
478pcap_compile_nopcap(int snaplen_arg, int linktype_arg,
479 struct bpf_program *program,
dfcad8d8 480 const char *buf, int optimize, bpf_u_int32 mask)
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481{
482 pcap_t *p;
483 int ret;
484
485 p = pcap_open_dead(linktype_arg, snaplen_arg);
486 if (p == NULL)
487 return (-1);
488 ret = pcap_compile(p, program, buf, optimize, mask);
489 pcap_close(p);
490 return (ret);
491}
492
493/*
494 * Clean up a "struct bpf_program" by freeing all the memory allocated
495 * in it.
496 */
497void
498pcap_freecode(struct bpf_program *program)
499{
500 program->bf_len = 0;
501 if (program->bf_insns != NULL) {
502 free((char *)program->bf_insns);
503 program->bf_insns = NULL;
504 }
505}
506
507/*
508 * Backpatch the blocks in 'list' to 'target'. The 'sense' field indicates
509 * which of the jt and jf fields has been resolved and which is a pointer
510 * back to another unresolved block (or nil). At least one of the fields
511 * in each block is already resolved.
512 */
513static void
514backpatch(list, target)
515 struct block *list, *target;
516{
517 struct block *next;
518
519 while (list) {
520 if (!list->sense) {
521 next = JT(list);
522 JT(list) = target;
523 } else {
524 next = JF(list);
525 JF(list) = target;
526 }
527 list = next;
528 }
529}
530
531/*
532 * Merge the lists in b0 and b1, using the 'sense' field to indicate
533 * which of jt and jf is the link.
534 */
535static void
536merge(b0, b1)
537 struct block *b0, *b1;
538{
539 register struct block **p = &b0;
540
541 /* Find end of list. */
542 while (*p)
543 p = !((*p)->sense) ? &JT(*p) : &JF(*p);
544
545 /* Concatenate the lists. */
546 *p = b1;
547}
548
549void
550finish_parse(p)
551 struct block *p;
552{
dfcad8d8 553 struct block *ppi_dlt_check;
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554
555 /*
556 * Insert before the statements of the first (root) block any
557 * statements needed to load the lengths of any variable-length
558 * headers into registers.
559 *
560 * XXX - a fancier strategy would be to insert those before the
561 * statements of all blocks that use those lengths and that
562 * have no predecessors that use them, so that we only compute
563 * the lengths if we need them. There might be even better
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564 * approaches than that.
565 *
566 * However, those strategies would be more complicated, and
567 * as we don't generate code to compute a length if the
568 * program has no tests that use the length, and as most
569 * tests will probably use those lengths, we would just
570 * postpone computing the lengths so that it's not done
571 * for tests that fail early, and it's not clear that's
572 * worth the effort.
23fa89e6 573 */
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574 insert_compute_vloffsets(p->head);
575
576 /*
577 * For DLT_PPI captures, generate a check of the per-packet
578 * DLT value to make sure it's DLT_IEEE802_11.
23fa89e6 579 */
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580 ppi_dlt_check = gen_ppi_dlt_check();
581 if (ppi_dlt_check != NULL)
582 gen_and(ppi_dlt_check, p);
dfcad8d8 583
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584 backpatch(p, gen_retblk(snaplen));
585 p->sense = !p->sense;
586 backpatch(p, gen_retblk(0));
587 root = p->head;
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588}
589
590void
591gen_and(b0, b1)
592 struct block *b0, *b1;
593{
594 backpatch(b0, b1->head);
595 b0->sense = !b0->sense;
596 b1->sense = !b1->sense;
597 merge(b1, b0);
598 b1->sense = !b1->sense;
599 b1->head = b0->head;
600}
601
602void
603gen_or(b0, b1)
604 struct block *b0, *b1;
605{
606 b0->sense = !b0->sense;
607 backpatch(b0, b1->head);
608 b0->sense = !b0->sense;
609 merge(b1, b0);
610 b1->head = b0->head;
611}
612
613void
614gen_not(b)
615 struct block *b;
616{
617 b->sense = !b->sense;
618}
619
620static struct block *
621gen_cmp(offrel, offset, size, v)
622 enum e_offrel offrel;
623 u_int offset, size;
624 bpf_int32 v;
625{
626 return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JEQ, 0, v);
627}
628
629static struct block *
630gen_cmp_gt(offrel, offset, size, v)
631 enum e_offrel offrel;
632 u_int offset, size;
633 bpf_int32 v;
634{
635 return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JGT, 0, v);
636}
637
638static struct block *
639gen_cmp_ge(offrel, offset, size, v)
640 enum e_offrel offrel;
641 u_int offset, size;
642 bpf_int32 v;
643{
644 return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JGE, 0, v);
645}
646
647static struct block *
648gen_cmp_lt(offrel, offset, size, v)
649 enum e_offrel offrel;
650 u_int offset, size;
651 bpf_int32 v;
652{
653 return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JGE, 1, v);
654}
655
656static struct block *
657gen_cmp_le(offrel, offset, size, v)
658 enum e_offrel offrel;
659 u_int offset, size;
660 bpf_int32 v;
661{
662 return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JGT, 1, v);
663}
664
665static struct block *
666gen_mcmp(offrel, offset, size, v, mask)
667 enum e_offrel offrel;
668 u_int offset, size;
669 bpf_int32 v;
670 bpf_u_int32 mask;
671{
672 return gen_ncmp(offrel, offset, size, mask, BPF_JEQ, 0, v);
673}
674
675static struct block *
676gen_bcmp(offrel, offset, size, v)
677 enum e_offrel offrel;
678 register u_int offset, size;
679 register const u_char *v;
680{
681 register struct block *b, *tmp;
682
683 b = NULL;
684 while (size >= 4) {
685 register const u_char *p = &v[size - 4];
686 bpf_int32 w = ((bpf_int32)p[0] << 24) |
687 ((bpf_int32)p[1] << 16) | ((bpf_int32)p[2] << 8) | p[3];
688
689 tmp = gen_cmp(offrel, offset + size - 4, BPF_W, w);
690 if (b != NULL)
691 gen_and(b, tmp);
692 b = tmp;
693 size -= 4;
694 }
695 while (size >= 2) {
696 register const u_char *p = &v[size - 2];
697 bpf_int32 w = ((bpf_int32)p[0] << 8) | p[1];
698
699 tmp = gen_cmp(offrel, offset + size - 2, BPF_H, w);
700 if (b != NULL)
701 gen_and(b, tmp);
702 b = tmp;
703 size -= 2;
704 }
705 if (size > 0) {
706 tmp = gen_cmp(offrel, offset, BPF_B, (bpf_int32)v[0]);
707 if (b != NULL)
708 gen_and(b, tmp);
709 b = tmp;
710 }
711 return b;
712}
713
714/*
715 * AND the field of size "size" at offset "offset" relative to the header
716 * specified by "offrel" with "mask", and compare it with the value "v"
717 * with the test specified by "jtype"; if "reverse" is true, the test
718 * should test the opposite of "jtype".
719 */
720static struct block *
721gen_ncmp(offrel, offset, size, mask, jtype, reverse, v)
722 enum e_offrel offrel;
723 bpf_int32 v;
724 bpf_u_int32 offset, size, mask, jtype;
725 int reverse;
726{
727 struct slist *s, *s2;
728 struct block *b;
729
730 s = gen_load_a(offrel, offset, size);
731
732 if (mask != 0xffffffff) {
733 s2 = new_stmt(BPF_ALU|BPF_AND|BPF_K);
734 s2->s.k = mask;
735 sappend(s, s2);
736 }
737
738 b = new_block(JMP(jtype));
739 b->stmts = s;
740 b->s.k = v;
741 if (reverse && (jtype == BPF_JGT || jtype == BPF_JGE))
742 gen_not(b);
743 return b;
744}
745
746/*
747 * Various code constructs need to know the layout of the data link
748 * layer. These variables give the necessary offsets from the beginning
749 * of the packet data.
23fa89e6 750 */
23fa89e6
PA
751
752/*
753 * This is the offset of the beginning of the link-layer header from
754 * the beginning of the raw packet data.
755 *
756 * It's usually 0, except for 802.11 with a fixed-length radio header.
757 * (For 802.11 with a variable-length radio header, we have to generate
758 * code to compute that offset; off_ll is 0 in that case.)
759 */
760static u_int off_ll;
761
762/*
de0d3203
PA
763 * If there's a variable-length header preceding the link-layer header,
764 * "reg_off_ll" is the register number for a register containing the
765 * length of that header, and therefore the offset of the link-layer
766 * header from the beginning of the raw packet data. Otherwise,
767 * "reg_off_ll" is -1.
768 */
769static int reg_off_ll;
770
771/*
772 * This is the offset of the beginning of the MAC-layer header from
773 * the beginning of the link-layer header.
23fa89e6 774 * It's usually 0, except for ATM LANE, where it's the offset, relative
a85e14b0
PA
775 * to the beginning of the raw packet data, of the Ethernet header, and
776 * for Ethernet with various additional information.
23fa89e6
PA
777 */
778static u_int off_mac;
779
780/*
de0d3203
PA
781 * This is the offset of the beginning of the MAC-layer payload,
782 * from the beginning of the raw packet data.
783 *
784 * I.e., it's the sum of the length of the link-layer header (without,
785 * for example, any 802.2 LLC header, so it's the MAC-layer
786 * portion of that header), plus any prefix preceding the
787 * link-layer header.
788 */
789static u_int off_macpl;
790
791/*
792 * This is 1 if the offset of the beginning of the MAC-layer payload
793 * from the beginning of the link-layer header is variable-length.
794 */
795static int off_macpl_is_variable;
796
797/*
798 * If the link layer has variable_length headers, "reg_off_macpl"
799 * is the register number for a register containing the length of the
800 * link-layer header plus the length of any variable-length header
801 * preceding the link-layer header. Otherwise, "reg_off_macpl"
802 * is -1.
803 */
804static int reg_off_macpl;
805
806/*
23fa89e6
PA
807 * "off_linktype" is the offset to information in the link-layer header
808 * giving the packet type. This offset is relative to the beginning
809 * of the link-layer header (i.e., it doesn't include off_ll).
810 *
811 * For Ethernet, it's the offset of the Ethernet type field.
812 *
813 * For link-layer types that always use 802.2 headers, it's the
814 * offset of the LLC header.
815 *
816 * For PPP, it's the offset of the PPP type field.
817 *
818 * For Cisco HDLC, it's the offset of the CHDLC type field.
819 *
820 * For BSD loopback, it's the offset of the AF_ value.
821 *
822 * For Linux cooked sockets, it's the offset of the type field.
823 *
824 * It's set to -1 for no encapsulation, in which case, IP is assumed.
825 */
826static u_int off_linktype;
827
828/*
de0d3203
PA
829 * TRUE if "pppoes" appeared in the filter; it causes link-layer type
830 * checks to check the PPP header, assumed to follow a LAN-style link-
831 * layer header and a PPPoE session header.
832 */
833static int is_pppoes = 0;
834
835/*
23fa89e6
PA
836 * TRUE if the link layer includes an ATM pseudo-header.
837 */
838static int is_atm = 0;
839
840/*
841 * TRUE if "lane" appeared in the filter; it causes us to generate
842 * code that assumes LANE rather than LLC-encapsulated traffic in SunATM.
843 */
844static int is_lane = 0;
845
846/*
847 * These are offsets for the ATM pseudo-header.
848 */
849static u_int off_vpi;
850static u_int off_vci;
851static u_int off_proto;
852
853/*
dfcad8d8
PA
854 * These are offsets for the MTP2 fields.
855 */
856static u_int off_li;
857
858/*
23fa89e6
PA
859 * These are offsets for the MTP3 fields.
860 */
861static u_int off_sio;
862static u_int off_opc;
863static u_int off_dpc;
864static u_int off_sls;
865
866/*
867 * This is the offset of the first byte after the ATM pseudo_header,
868 * or -1 if there is no ATM pseudo-header.
869 */
870static u_int off_payload;
871
872/*
873 * These are offsets to the beginning of the network-layer header.
de0d3203
PA
874 * They are relative to the beginning of the MAC-layer payload (i.e.,
875 * they don't include off_ll or off_macpl).
23fa89e6
PA
876 *
877 * If the link layer never uses 802.2 LLC:
878 *
879 * "off_nl" and "off_nl_nosnap" are the same.
880 *
881 * If the link layer always uses 802.2 LLC:
882 *
883 * "off_nl" is the offset if there's a SNAP header following
884 * the 802.2 header;
885 *
886 * "off_nl_nosnap" is the offset if there's no SNAP header.
887 *
888 * If the link layer is Ethernet:
889 *
890 * "off_nl" is the offset if the packet is an Ethernet II packet
891 * (we assume no 802.3+802.2+SNAP);
892 *
893 * "off_nl_nosnap" is the offset if the packet is an 802.3 packet
894 * with an 802.2 header following it.
895 */
896static u_int off_nl;
897static u_int off_nl_nosnap;
898
899static int linktype;
900
901static void
902init_linktype(p)
903 pcap_t *p;
904{
905 linktype = pcap_datalink(p);
906#ifdef PCAP_FDDIPAD
907 pcap_fddipad = p->fddipad;
908#endif
909
910 /*
911 * Assume it's not raw ATM with a pseudo-header, for now.
912 */
913 off_mac = 0;
914 is_atm = 0;
915 is_lane = 0;
916 off_vpi = -1;
917 off_vci = -1;
918 off_proto = -1;
919 off_payload = -1;
920
921 /*
de0d3203
PA
922 * And that we're not doing PPPoE.
923 */
924 is_pppoes = 0;
925
926 /*
23fa89e6
PA
927 * And assume we're not doing SS7.
928 */
dfcad8d8 929 off_li = -1;
23fa89e6
PA
930 off_sio = -1;
931 off_opc = -1;
932 off_dpc = -1;
933 off_sls = -1;
934
935 /*
de0d3203 936 * Also assume it's not 802.11.
23fa89e6
PA
937 */
938 off_ll = 0;
de0d3203
PA
939 off_macpl = 0;
940 off_macpl_is_variable = 0;
23fa89e6
PA
941
942 orig_linktype = -1;
943 orig_nl = -1;
944 label_stack_depth = 0;
945
de0d3203
PA
946 reg_off_ll = -1;
947 reg_off_macpl = -1;
23fa89e6
PA
948
949 switch (linktype) {
950
951 case DLT_ARCNET:
952 off_linktype = 2;
de0d3203
PA
953 off_macpl = 6;
954 off_nl = 0; /* XXX in reality, variable! */
955 off_nl_nosnap = 0; /* no 802.2 LLC */
23fa89e6
PA
956 return;
957
958 case DLT_ARCNET_LINUX:
959 off_linktype = 4;
de0d3203
PA
960 off_macpl = 8;
961 off_nl = 0; /* XXX in reality, variable! */
962 off_nl_nosnap = 0; /* no 802.2 LLC */
23fa89e6
PA
963 return;
964
965 case DLT_EN10MB:
966 off_linktype = 12;
de0d3203
PA
967 off_macpl = 14; /* Ethernet header length */
968 off_nl = 0; /* Ethernet II */
969 off_nl_nosnap = 3; /* 802.3+802.2 */
23fa89e6
PA
970 return;
971
972 case DLT_SLIP:
973 /*
974 * SLIP doesn't have a link level type. The 16 byte
975 * header is hacked into our SLIP driver.
976 */
977 off_linktype = -1;
de0d3203
PA
978 off_macpl = 16;
979 off_nl = 0;
980 off_nl_nosnap = 0; /* no 802.2 LLC */
23fa89e6
PA
981 return;
982
983 case DLT_SLIP_BSDOS:
984 /* XXX this may be the same as the DLT_PPP_BSDOS case */
985 off_linktype = -1;
986 /* XXX end */
de0d3203
PA
987 off_macpl = 24;
988 off_nl = 0;
989 off_nl_nosnap = 0; /* no 802.2 LLC */
23fa89e6
PA
990 return;
991
992 case DLT_NULL:
993 case DLT_LOOP:
994 off_linktype = 0;
de0d3203
PA
995 off_macpl = 4;
996 off_nl = 0;
997 off_nl_nosnap = 0; /* no 802.2 LLC */
23fa89e6
PA
998 return;
999
1000 case DLT_ENC:
1001 off_linktype = 0;
de0d3203
PA
1002 off_macpl = 12;
1003 off_nl = 0;
1004 off_nl_nosnap = 0; /* no 802.2 LLC */
23fa89e6
PA
1005 return;
1006
1007 case DLT_PPP:
1008 case DLT_PPP_PPPD:
1009 case DLT_C_HDLC: /* BSD/OS Cisco HDLC */
1010 case DLT_PPP_SERIAL: /* NetBSD sync/async serial PPP */
1011 off_linktype = 2;
de0d3203
PA
1012 off_macpl = 4;
1013 off_nl = 0;
1014 off_nl_nosnap = 0; /* no 802.2 LLC */
23fa89e6
PA
1015 return;
1016
1017 case DLT_PPP_ETHER:
1018 /*
1019 * This does no include the Ethernet header, and
1020 * only covers session state.
1021 */
1022 off_linktype = 6;
de0d3203
PA
1023 off_macpl = 8;
1024 off_nl = 0;
1025 off_nl_nosnap = 0; /* no 802.2 LLC */
23fa89e6
PA
1026 return;
1027
1028 case DLT_PPP_BSDOS:
1029 off_linktype = 5;
de0d3203
PA
1030 off_macpl = 24;
1031 off_nl = 0;
1032 off_nl_nosnap = 0; /* no 802.2 LLC */
23fa89e6
PA
1033 return;
1034
1035 case DLT_FDDI:
1036 /*
1037 * FDDI doesn't really have a link-level type field.
1038 * We set "off_linktype" to the offset of the LLC header.
1039 *
1040 * To check for Ethernet types, we assume that SSAP = SNAP
1041 * is being used and pick out the encapsulated Ethernet type.
1042 * XXX - should we generate code to check for SNAP?
1043 */
1044 off_linktype = 13;
1045#ifdef PCAP_FDDIPAD
1046 off_linktype += pcap_fddipad;
1047#endif
de0d3203 1048 off_macpl = 13; /* FDDI MAC header length */
23fa89e6 1049#ifdef PCAP_FDDIPAD
de0d3203 1050 off_macpl += pcap_fddipad;
23fa89e6 1051#endif
de0d3203
PA
1052 off_nl = 8; /* 802.2+SNAP */
1053 off_nl_nosnap = 3; /* 802.2 */
23fa89e6
PA
1054 return;
1055
1056 case DLT_IEEE802:
1057 /*
1058 * Token Ring doesn't really have a link-level type field.
1059 * We set "off_linktype" to the offset of the LLC header.
1060 *
1061 * To check for Ethernet types, we assume that SSAP = SNAP
1062 * is being used and pick out the encapsulated Ethernet type.
1063 * XXX - should we generate code to check for SNAP?
1064 *
1065 * XXX - the header is actually variable-length.
1066 * Some various Linux patched versions gave 38
1067 * as "off_linktype" and 40 as "off_nl"; however,
1068 * if a token ring packet has *no* routing
1069 * information, i.e. is not source-routed, the correct
1070 * values are 20 and 22, as they are in the vanilla code.
1071 *
1072 * A packet is source-routed iff the uppermost bit
1073 * of the first byte of the source address, at an
1074 * offset of 8, has the uppermost bit set. If the
1075 * packet is source-routed, the total number of bytes
1076 * of routing information is 2 plus bits 0x1F00 of
1077 * the 16-bit value at an offset of 14 (shifted right
1078 * 8 - figure out which byte that is).
1079 */
1080 off_linktype = 14;
de0d3203
PA
1081 off_macpl = 14; /* Token Ring MAC header length */
1082 off_nl = 8; /* 802.2+SNAP */
1083 off_nl_nosnap = 3; /* 802.2 */
23fa89e6
PA
1084 return;
1085
1086 case DLT_IEEE802_11:
de0d3203
PA
1087 case DLT_PRISM_HEADER:
1088 case DLT_IEEE802_11_RADIO_AVS:
1089 case DLT_IEEE802_11_RADIO:
23fa89e6
PA
1090 /*
1091 * 802.11 doesn't really have a link-level type field.
1092 * We set "off_linktype" to the offset of the LLC header.
1093 *
1094 * To check for Ethernet types, we assume that SSAP = SNAP
1095 * is being used and pick out the encapsulated Ethernet type.
1096 * XXX - should we generate code to check for SNAP?
1097 *
de0d3203
PA
1098 * We also handle variable-length radio headers here.
1099 * The Prism header is in theory variable-length, but in
1100 * practice it's always 144 bytes long. However, some
1101 * drivers on Linux use ARPHRD_IEEE80211_PRISM, but
1102 * sometimes or always supply an AVS header, so we
1103 * have to check whether the radio header is a Prism
1104 * header or an AVS header, so, in practice, it's
1105 * variable-length.
23fa89e6 1106 */
23fa89e6 1107 off_linktype = 24;
de0d3203
PA
1108 off_macpl = 0; /* link-layer header is variable-length */
1109 off_macpl_is_variable = 1;
1110 off_nl = 8; /* 802.2+SNAP */
1111 off_nl_nosnap = 3; /* 802.2 */
23fa89e6
PA
1112 return;
1113
dfcad8d8 1114 case DLT_PPI:
de0d3203
PA
1115 /*
1116 * At the moment we treat PPI the same way that we treat
1117 * normal Radiotap encoded packets. The difference is in
1118 * the function that generates the code at the beginning
1119 * to compute the header length. Since this code generator
1120 * of PPI supports bare 802.11 encapsulation only (i.e.
1121 * the encapsulated DLT should be DLT_IEEE802_11) we
1122 * generate code to check for this too.
23fa89e6
PA
1123 */
1124 off_linktype = 24;
de0d3203
PA
1125 off_macpl = 0; /* link-layer header is variable-length */
1126 off_macpl_is_variable = 1;
1127 off_nl = 8; /* 802.2+SNAP */
1128 off_nl_nosnap = 3; /* 802.2 */
23fa89e6
PA
1129 return;
1130
1131 case DLT_ATM_RFC1483:
1132 case DLT_ATM_CLIP: /* Linux ATM defines this */
1133 /*
1134 * assume routed, non-ISO PDUs
1135 * (i.e., LLC = 0xAA-AA-03, OUT = 0x00-00-00)
1136 *
1137 * XXX - what about ISO PDUs, e.g. CLNP, ISIS, ESIS,
1138 * or PPP with the PPP NLPID (e.g., PPPoA)? The
1139 * latter would presumably be treated the way PPPoE
1140 * should be, so you can do "pppoe and udp port 2049"
1141 * or "pppoa and tcp port 80" and have it check for
1142 * PPPo{A,E} and a PPP protocol of IP and....
1143 */
1144 off_linktype = 0;
de0d3203 1145 off_macpl = 0; /* packet begins with LLC header */
23fa89e6
PA
1146 off_nl = 8; /* 802.2+SNAP */
1147 off_nl_nosnap = 3; /* 802.2 */
1148 return;
1149
1150 case DLT_SUNATM:
1151 /*
1152 * Full Frontal ATM; you get AALn PDUs with an ATM
1153 * pseudo-header.
1154 */
1155 is_atm = 1;
1156 off_vpi = SUNATM_VPI_POS;
1157 off_vci = SUNATM_VCI_POS;
1158 off_proto = PROTO_POS;
de0d3203 1159 off_mac = -1; /* assume LLC-encapsulated, so no MAC-layer header */
23fa89e6
PA
1160 off_payload = SUNATM_PKT_BEGIN_POS;
1161 off_linktype = off_payload;
de0d3203
PA
1162 off_macpl = off_payload; /* if LLC-encapsulated */
1163 off_nl = 8; /* 802.2+SNAP */
1164 off_nl_nosnap = 3; /* 802.2 */
23fa89e6
PA
1165 return;
1166
1167 case DLT_RAW:
a85e14b0
PA
1168 case DLT_IPV4:
1169 case DLT_IPV6:
23fa89e6 1170 off_linktype = -1;
de0d3203 1171 off_macpl = 0;
23fa89e6
PA
1172 off_nl = 0;
1173 off_nl_nosnap = 0; /* no 802.2 LLC */
1174 return;
1175
1176 case DLT_LINUX_SLL: /* fake header for Linux cooked socket */
1177 off_linktype = 14;
de0d3203
PA
1178 off_macpl = 16;
1179 off_nl = 0;
1180 off_nl_nosnap = 0; /* no 802.2 LLC */
23fa89e6
PA
1181 return;
1182
1183 case DLT_LTALK:
1184 /*
1185 * LocalTalk does have a 1-byte type field in the LLAP header,
1186 * but really it just indicates whether there is a "short" or
1187 * "long" DDP packet following.
1188 */
1189 off_linktype = -1;
de0d3203 1190 off_macpl = 0;
23fa89e6
PA
1191 off_nl = 0;
1192 off_nl_nosnap = 0; /* no 802.2 LLC */
1193 return;
1194
1195 case DLT_IP_OVER_FC:
1196 /*
1197 * RFC 2625 IP-over-Fibre-Channel doesn't really have a
1198 * link-level type field. We set "off_linktype" to the
1199 * offset of the LLC header.
1200 *
1201 * To check for Ethernet types, we assume that SSAP = SNAP
1202 * is being used and pick out the encapsulated Ethernet type.
1203 * XXX - should we generate code to check for SNAP? RFC
1204 * 2625 says SNAP should be used.
1205 */
1206 off_linktype = 16;
de0d3203
PA
1207 off_macpl = 16;
1208 off_nl = 8; /* 802.2+SNAP */
1209 off_nl_nosnap = 3; /* 802.2 */
23fa89e6
PA
1210 return;
1211
1212 case DLT_FRELAY:
1213 /*
1214 * XXX - we should set this to handle SNAP-encapsulated
1215 * frames (NLPID of 0x80).
1216 */
1217 off_linktype = -1;
de0d3203 1218 off_macpl = 0;
23fa89e6
PA
1219 off_nl = 0;
1220 off_nl_nosnap = 0; /* no 802.2 LLC */
1221 return;
1222
1223 /*
1224 * the only BPF-interesting FRF.16 frames are non-control frames;
1225 * Frame Relay has a variable length link-layer
1226 * so lets start with offset 4 for now and increments later on (FIXME);
1227 */
1228 case DLT_MFR:
1229 off_linktype = -1;
de0d3203 1230 off_macpl = 0;
23fa89e6
PA
1231 off_nl = 4;
1232 off_nl_nosnap = 0; /* XXX - for now -> no 802.2 LLC */
1233 return;
1234
1235 case DLT_APPLE_IP_OVER_IEEE1394:
1236 off_linktype = 16;
de0d3203
PA
1237 off_macpl = 18;
1238 off_nl = 0;
1239 off_nl_nosnap = 0; /* no 802.2 LLC */
23fa89e6
PA
1240 return;
1241
23fa89e6
PA
1242 case DLT_SYMANTEC_FIREWALL:
1243 off_linktype = 6;
de0d3203
PA
1244 off_macpl = 44;
1245 off_nl = 0; /* Ethernet II */
1246 off_nl_nosnap = 0; /* XXX - what does it do with 802.3 packets? */
23fa89e6
PA
1247 return;
1248
084fe320 1249#ifdef HAVE_NET_PFVAR_H
23fa89e6
PA
1250 case DLT_PFLOG:
1251 off_linktype = 0;
de0d3203
PA
1252 off_macpl = PFLOG_HDRLEN;
1253 off_nl = 0;
1254 off_nl_nosnap = 0; /* no 802.2 LLC */
23fa89e6 1255 return;
084fe320 1256#endif
23fa89e6
PA
1257
1258 case DLT_JUNIPER_MFR:
1259 case DLT_JUNIPER_MLFR:
1260 case DLT_JUNIPER_MLPPP:
1261 case DLT_JUNIPER_PPP:
1262 case DLT_JUNIPER_CHDLC:
1263 case DLT_JUNIPER_FRELAY:
1264 off_linktype = 4;
de0d3203
PA
1265 off_macpl = 4;
1266 off_nl = 0;
23fa89e6
PA
1267 off_nl_nosnap = -1; /* no 802.2 LLC */
1268 return;
1269
1270 case DLT_JUNIPER_ATM1:
de0d3203
PA
1271 off_linktype = 4; /* in reality variable between 4-8 */
1272 off_macpl = 4; /* in reality variable between 4-8 */
1273 off_nl = 0;
1274 off_nl_nosnap = 10;
23fa89e6
PA
1275 return;
1276
1277 case DLT_JUNIPER_ATM2:
de0d3203
PA
1278 off_linktype = 8; /* in reality variable between 8-12 */
1279 off_macpl = 8; /* in reality variable between 8-12 */
1280 off_nl = 0;
1281 off_nl_nosnap = 10;
23fa89e6
PA
1282 return;
1283
1284 /* frames captured on a Juniper PPPoE service PIC
1285 * contain raw ethernet frames */
1286 case DLT_JUNIPER_PPPOE:
1287 case DLT_JUNIPER_ETHER:
de0d3203 1288 off_macpl = 14;
23fa89e6
PA
1289 off_linktype = 16;
1290 off_nl = 18; /* Ethernet II */
1291 off_nl_nosnap = 21; /* 802.3+802.2 */
1292 return;
1293
1294 case DLT_JUNIPER_PPPOE_ATM:
1295 off_linktype = 4;
de0d3203
PA
1296 off_macpl = 6;
1297 off_nl = 0;
1298 off_nl_nosnap = -1; /* no 802.2 LLC */
23fa89e6
PA
1299 return;
1300
1301 case DLT_JUNIPER_GGSN:
1302 off_linktype = 6;
de0d3203
PA
1303 off_macpl = 12;
1304 off_nl = 0;
1305 off_nl_nosnap = -1; /* no 802.2 LLC */
23fa89e6
PA
1306 return;
1307
1308 case DLT_JUNIPER_ES:
1309 off_linktype = 6;
de0d3203
PA
1310 off_macpl = -1; /* not really a network layer but raw IP addresses */
1311 off_nl = -1; /* not really a network layer but raw IP addresses */
23fa89e6
PA
1312 off_nl_nosnap = -1; /* no 802.2 LLC */
1313 return;
1314
1315 case DLT_JUNIPER_MONITOR:
1316 off_linktype = 12;
de0d3203
PA
1317 off_macpl = 12;
1318 off_nl = 0; /* raw IP/IP6 header */
23fa89e6
PA
1319 off_nl_nosnap = -1; /* no 802.2 LLC */
1320 return;
1321
1322 case DLT_JUNIPER_SERVICES:
1323 off_linktype = 12;
de0d3203 1324 off_macpl = -1; /* L3 proto location dep. on cookie type */
23fa89e6
PA
1325 off_nl = -1; /* L3 proto location dep. on cookie type */
1326 off_nl_nosnap = -1; /* no 802.2 LLC */
1327 return;
1328
dfcad8d8
PA
1329 case DLT_JUNIPER_VP:
1330 off_linktype = 18;
de0d3203
PA
1331 off_macpl = -1;
1332 off_nl = -1;
1333 off_nl_nosnap = -1;
1334 return;
1335
1336 case DLT_JUNIPER_ST:
1337 off_linktype = 18;
1338 off_macpl = -1;
1339 off_nl = -1;
1340 off_nl_nosnap = -1;
1341 return;
1342
1343 case DLT_JUNIPER_ISM:
1344 off_linktype = 8;
1345 off_macpl = -1;
dfcad8d8
PA
1346 off_nl = -1;
1347 off_nl_nosnap = -1;
1348 return;
1349
a85e14b0
PA
1350 case DLT_JUNIPER_VS:
1351 case DLT_JUNIPER_SRX_E2E:
1352 case DLT_JUNIPER_FIBRECHANNEL:
1353 case DLT_JUNIPER_ATM_CEMIC:
1354 off_linktype = 8;
1355 off_macpl = -1;
1356 off_nl = -1;
1357 off_nl_nosnap = -1;
1358 return;
1359
23fa89e6 1360 case DLT_MTP2:
dfcad8d8 1361 off_li = 2;
23fa89e6
PA
1362 off_sio = 3;
1363 off_opc = 4;
1364 off_dpc = 4;
1365 off_sls = 7;
1366 off_linktype = -1;
de0d3203 1367 off_macpl = -1;
23fa89e6
PA
1368 off_nl = -1;
1369 off_nl_nosnap = -1;
1370 return;
1371
dfcad8d8
PA
1372 case DLT_MTP2_WITH_PHDR:
1373 off_li = 6;
1374 off_sio = 7;
1375 off_opc = 8;
1376 off_dpc = 8;
1377 off_sls = 11;
1378 off_linktype = -1;
de0d3203
PA
1379 off_macpl = -1;
1380 off_nl = -1;
1381 off_nl_nosnap = -1;
1382 return;
1383
1384 case DLT_ERF:
1385 off_li = 22;
1386 off_sio = 23;
1387 off_opc = 24;
1388 off_dpc = 24;
1389 off_sls = 27;
1390 off_linktype = -1;
1391 off_macpl = -1;
dfcad8d8
PA
1392 off_nl = -1;
1393 off_nl_nosnap = -1;
1394 return;
1395
23fa89e6
PA
1396#ifdef DLT_PFSYNC
1397 case DLT_PFSYNC:
1398 off_linktype = -1;
de0d3203
PA
1399 off_macpl = 4;
1400 off_nl = 0;
1401 off_nl_nosnap = 0;
23fa89e6
PA
1402 return;
1403#endif
1404
a85e14b0 1405 case DLT_AX25_KISS:
de0d3203
PA
1406 /*
1407 * Currently, only raw "link[N:M]" filtering is supported.
1408 */
a85e14b0 1409 off_linktype = -1; /* variable, min 15, max 71 steps of 7 */
de0d3203 1410 off_macpl = -1;
a85e14b0
PA
1411 off_nl = -1; /* variable, min 16, max 71 steps of 7 */
1412 off_nl_nosnap = -1; /* no 802.2 LLC */
1413 off_mac = 1; /* step over the kiss length byte */
de0d3203
PA
1414 return;
1415
a85e14b0
PA
1416 case DLT_IPNET:
1417 off_linktype = 1;
1418 off_macpl = 24; /* ipnet header length */
1419 off_nl = 0;
de0d3203
PA
1420 off_nl_nosnap = -1;
1421 return;
1422
a85e14b0
PA
1423 case DLT_NETANALYZER:
1424 off_mac = 4; /* MAC header is past 4-byte pseudo-header */
1425 off_linktype = 16; /* includes 4-byte pseudo-header */
1426 off_macpl = 18; /* pseudo-header+Ethernet header length */
1427 off_nl = 0; /* Ethernet II */
1428 off_nl_nosnap = 3; /* 802.3+802.2 */
de0d3203
PA
1429 return;
1430
a85e14b0
PA
1431 case DLT_NETANALYZER_TRANSPARENT:
1432 off_mac = 12; /* MAC header is past 4-byte pseudo-header, preamble, and SFD */
1433 off_linktype = 24; /* includes 4-byte pseudo-header+preamble+SFD */
1434 off_macpl = 26; /* pseudo-header+preamble+SFD+Ethernet header length */
1435 off_nl = 0; /* Ethernet II */
1436 off_nl_nosnap = 3; /* 802.3+802.2 */
de0d3203
PA
1437 return;
1438
a85e14b0 1439 default:
de0d3203 1440 /*
a85e14b0
PA
1441 * For values in the range in which we've assigned new
1442 * DLT_ values, only raw "link[N:M]" filtering is supported.
de0d3203 1443 */
a85e14b0
PA
1444 if (linktype >= DLT_MATCHING_MIN &&
1445 linktype <= DLT_MATCHING_MAX) {
1446 off_linktype = -1;
1447 off_macpl = -1;
1448 off_nl = -1;
1449 off_nl_nosnap = -1;
1450 return;
1451 }
de0d3203 1452
23fa89e6
PA
1453 }
1454 bpf_error("unknown data link type %d", linktype);
1455 /* NOTREACHED */
1456}
1457
1458/*
1459 * Load a value relative to the beginning of the link-layer header.
1460 * The link-layer header doesn't necessarily begin at the beginning
1461 * of the packet data; there might be a variable-length prefix containing
1462 * radio information.
1463 */
1464static struct slist *
1465gen_load_llrel(offset, size)
1466 u_int offset, size;
1467{
1468 struct slist *s, *s2;
1469
1470 s = gen_llprefixlen();
1471
1472 /*
1473 * If "s" is non-null, it has code to arrange that the X register
1474 * contains the length of the prefix preceding the link-layer
1475 * header.
1476 *
1477 * Otherwise, the length of the prefix preceding the link-layer
1478 * header is "off_ll".
1479 */
1480 if (s != NULL) {
1481 /*
1482 * There's a variable-length prefix preceding the
1483 * link-layer header. "s" points to a list of statements
1484 * that put the length of that prefix into the X register.
1485 * do an indirect load, to use the X register as an offset.
1486 */
1487 s2 = new_stmt(BPF_LD|BPF_IND|size);
1488 s2->s.k = offset;
1489 sappend(s, s2);
1490 } else {
1491 /*
1492 * There is no variable-length header preceding the
1493 * link-layer header; add in off_ll, which, if there's
1494 * a fixed-length header preceding the link-layer header,
1495 * is the length of that header.
1496 */
1497 s = new_stmt(BPF_LD|BPF_ABS|size);
1498 s->s.k = offset + off_ll;
1499 }
1500 return s;
1501}
1502
de0d3203
PA
1503/*
1504 * Load a value relative to the beginning of the MAC-layer payload.
1505 */
1506static struct slist *
1507gen_load_macplrel(offset, size)
1508 u_int offset, size;
1509{
1510 struct slist *s, *s2;
1511
1512 s = gen_off_macpl();
1513
1514 /*
1515 * If s is non-null, the offset of the MAC-layer payload is
1516 * variable, and s points to a list of instructions that
1517 * arrange that the X register contains that offset.
1518 *
1519 * Otherwise, the offset of the MAC-layer payload is constant,
1520 * and is in off_macpl.
1521 */
1522 if (s != NULL) {
1523 /*
1524 * The offset of the MAC-layer payload is in the X
1525 * register. Do an indirect load, to use the X register
1526 * as an offset.
1527 */
1528 s2 = new_stmt(BPF_LD|BPF_IND|size);
1529 s2->s.k = offset;
1530 sappend(s, s2);
1531 } else {
1532 /*
1533 * The offset of the MAC-layer payload is constant,
1534 * and is in off_macpl; load the value at that offset
1535 * plus the specified offset.
1536 */
1537 s = new_stmt(BPF_LD|BPF_ABS|size);
1538 s->s.k = off_macpl + offset;
1539 }
1540 return s;
1541}
dfcad8d8 1542
23fa89e6
PA
1543/*
1544 * Load a value relative to the beginning of the specified header.
1545 */
1546static struct slist *
1547gen_load_a(offrel, offset, size)
1548 enum e_offrel offrel;
1549 u_int offset, size;
1550{
1551 struct slist *s, *s2;
1552
1553 switch (offrel) {
1554
1555 case OR_PACKET:
1556 s = new_stmt(BPF_LD|BPF_ABS|size);
1557 s->s.k = offset;
1558 break;
1559
1560 case OR_LINK:
1561 s = gen_load_llrel(offset, size);
1562 break;
1563
de0d3203
PA
1564 case OR_MACPL:
1565 s = gen_load_macplrel(offset, size);
1566 break;
1567
23fa89e6 1568 case OR_NET:
de0d3203 1569 s = gen_load_macplrel(off_nl + offset, size);
23fa89e6
PA
1570 break;
1571
1572 case OR_NET_NOSNAP:
de0d3203 1573 s = gen_load_macplrel(off_nl_nosnap + offset, size);
23fa89e6
PA
1574 break;
1575
1576 case OR_TRAN_IPV4:
1577 /*
1578 * Load the X register with the length of the IPv4 header
1579 * (plus the offset of the link-layer header, if it's
1580 * preceded by a variable-length header such as a radio
1581 * header), in bytes.
1582 */
1583 s = gen_loadx_iphdrlen();
1584
1585 /*
de0d3203
PA
1586 * Load the item at {offset of the MAC-layer payload} +
1587 * {offset, relative to the start of the MAC-layer
1588 * paylod, of the IPv4 header} + {length of the IPv4 header} +
23fa89e6
PA
1589 * {specified offset}.
1590 *
de0d3203
PA
1591 * (If the offset of the MAC-layer payload is variable,
1592 * it's included in the value in the X register, and
1593 * off_macpl is 0.)
23fa89e6
PA
1594 */
1595 s2 = new_stmt(BPF_LD|BPF_IND|size);
de0d3203 1596 s2->s.k = off_macpl + off_nl + offset;
23fa89e6
PA
1597 sappend(s, s2);
1598 break;
1599
1600 case OR_TRAN_IPV6:
de0d3203 1601 s = gen_load_macplrel(off_nl + 40 + offset, size);
23fa89e6
PA
1602 break;
1603
1604 default:
1605 abort();
1606 return NULL;
1607 }
1608 return s;
1609}
1610
1611/*
1612 * Generate code to load into the X register the sum of the length of
1613 * the IPv4 header and any variable-length header preceding the link-layer
1614 * header.
1615 */
1616static struct slist *
1617gen_loadx_iphdrlen()
1618{
1619 struct slist *s, *s2;
1620
de0d3203 1621 s = gen_off_macpl();
23fa89e6
PA
1622 if (s != NULL) {
1623 /*
1624 * There's a variable-length prefix preceding the
de0d3203
PA
1625 * link-layer header, or the link-layer header is itself
1626 * variable-length. "s" points to a list of statements
1627 * that put the offset of the MAC-layer payload into
1628 * the X register.
1629 *
23fa89e6
PA
1630 * The 4*([k]&0xf) addressing mode can't be used, as we
1631 * don't have a constant offset, so we have to load the
1632 * value in question into the A register and add to it
1633 * the value from the X register.
1634 */
1635 s2 = new_stmt(BPF_LD|BPF_IND|BPF_B);
1636 s2->s.k = off_nl;
1637 sappend(s, s2);
1638 s2 = new_stmt(BPF_ALU|BPF_AND|BPF_K);
1639 s2->s.k = 0xf;
1640 sappend(s, s2);
1641 s2 = new_stmt(BPF_ALU|BPF_LSH|BPF_K);
1642 s2->s.k = 2;
1643 sappend(s, s2);
1644
1645 /*
1646 * The A register now contains the length of the
de0d3203
PA
1647 * IP header. We need to add to it the offset of
1648 * the MAC-layer payload, which is still in the X
1649 * register, and move the result into the X register.
23fa89e6
PA
1650 */
1651 sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X));
1652 sappend(s, new_stmt(BPF_MISC|BPF_TAX));
1653 } else {
1654 /*
1655 * There is no variable-length header preceding the
de0d3203
PA
1656 * link-layer header, and the link-layer header is
1657 * fixed-length; load the length of the IPv4 header,
1658 * which is at an offset of off_nl from the beginning
1659 * of the MAC-layer payload, and thus at an offset
1660 * of off_mac_pl + off_nl from the beginning of the
1661 * raw packet data.
23fa89e6
PA
1662 */
1663 s = new_stmt(BPF_LDX|BPF_MSH|BPF_B);
de0d3203 1664 s->s.k = off_macpl + off_nl;
23fa89e6
PA
1665 }
1666 return s;
1667}
1668
1669static struct block *
1670gen_uncond(rsense)
1671 int rsense;
1672{
1673 struct block *b;
1674 struct slist *s;
1675
1676 s = new_stmt(BPF_LD|BPF_IMM);
1677 s->s.k = !rsense;
1678 b = new_block(JMP(BPF_JEQ));
1679 b->stmts = s;
1680
1681 return b;
1682}
1683
1684static inline struct block *
1685gen_true()
1686{
1687 return gen_uncond(1);
1688}
1689
1690static inline struct block *
1691gen_false()
1692{
1693 return gen_uncond(0);
1694}
1695
1696/*
1697 * Byte-swap a 32-bit number.
1698 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
1699 * big-endian platforms.)
1700 */
1701#define SWAPLONG(y) \
1702((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
1703
1704/*
1705 * Generate code to match a particular packet type.
1706 *
1707 * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
1708 * value, if <= ETHERMTU. We use that to determine whether to
1709 * match the type/length field or to check the type/length field for
1710 * a value <= ETHERMTU to see whether it's a type field and then do
1711 * the appropriate test.
1712 */
1713static struct block *
1714gen_ether_linktype(proto)
1715 register int proto;
1716{
1717 struct block *b0, *b1;
1718
1719 switch (proto) {
1720
1721 case LLCSAP_ISONS:
1722 case LLCSAP_IP:
1723 case LLCSAP_NETBEUI:
1724 /*
1725 * OSI protocols and NetBEUI always use 802.2 encapsulation,
1726 * so we check the DSAP and SSAP.
1727 *
1728 * LLCSAP_IP checks for IP-over-802.2, rather
1729 * than IP-over-Ethernet or IP-over-SNAP.
1730 *
1731 * XXX - should we check both the DSAP and the
1732 * SSAP, like this, or should we check just the
1733 * DSAP, as we do for other types <= ETHERMTU
1734 * (i.e., other SAP values)?
1735 */
1736 b0 = gen_cmp_gt(OR_LINK, off_linktype, BPF_H, ETHERMTU);
1737 gen_not(b0);
de0d3203 1738 b1 = gen_cmp(OR_MACPL, 0, BPF_H, (bpf_int32)
23fa89e6
PA
1739 ((proto << 8) | proto));
1740 gen_and(b0, b1);
1741 return b1;
1742
1743 case LLCSAP_IPX:
1744 /*
1745 * Check for;
1746 *
1747 * Ethernet_II frames, which are Ethernet
1748 * frames with a frame type of ETHERTYPE_IPX;
1749 *
1750 * Ethernet_802.3 frames, which are 802.3
1751 * frames (i.e., the type/length field is
1752 * a length field, <= ETHERMTU, rather than
1753 * a type field) with the first two bytes
1754 * after the Ethernet/802.3 header being
1755 * 0xFFFF;
1756 *
1757 * Ethernet_802.2 frames, which are 802.3
1758 * frames with an 802.2 LLC header and
1759 * with the IPX LSAP as the DSAP in the LLC
1760 * header;
1761 *
1762 * Ethernet_SNAP frames, which are 802.3
1763 * frames with an LLC header and a SNAP
1764 * header and with an OUI of 0x000000
1765 * (encapsulated Ethernet) and a protocol
1766 * ID of ETHERTYPE_IPX in the SNAP header.
1767 *
1768 * XXX - should we generate the same code both
1769 * for tests for LLCSAP_IPX and for ETHERTYPE_IPX?
1770 */
1771
1772 /*
1773 * This generates code to check both for the
1774 * IPX LSAP (Ethernet_802.2) and for Ethernet_802.3.
1775 */
de0d3203
PA
1776 b0 = gen_cmp(OR_MACPL, 0, BPF_B, (bpf_int32)LLCSAP_IPX);
1777 b1 = gen_cmp(OR_MACPL, 0, BPF_H, (bpf_int32)0xFFFF);
23fa89e6
PA
1778 gen_or(b0, b1);
1779
1780 /*
1781 * Now we add code to check for SNAP frames with
1782 * ETHERTYPE_IPX, i.e. Ethernet_SNAP.
1783 */
de0d3203 1784 b0 = gen_snap(0x000000, ETHERTYPE_IPX);
23fa89e6
PA
1785 gen_or(b0, b1);
1786
1787 /*
1788 * Now we generate code to check for 802.3
1789 * frames in general.
1790 */
1791 b0 = gen_cmp_gt(OR_LINK, off_linktype, BPF_H, ETHERMTU);
1792 gen_not(b0);
1793
1794 /*
1795 * Now add the check for 802.3 frames before the
1796 * check for Ethernet_802.2 and Ethernet_802.3,
1797 * as those checks should only be done on 802.3
1798 * frames, not on Ethernet frames.
1799 */
1800 gen_and(b0, b1);
1801
1802 /*
1803 * Now add the check for Ethernet_II frames, and
1804 * do that before checking for the other frame
1805 * types.
1806 */
1807 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H,
1808 (bpf_int32)ETHERTYPE_IPX);
1809 gen_or(b0, b1);
1810 return b1;
1811
1812 case ETHERTYPE_ATALK:
1813 case ETHERTYPE_AARP:
1814 /*
1815 * EtherTalk (AppleTalk protocols on Ethernet link
1816 * layer) may use 802.2 encapsulation.
1817 */
1818
1819 /*
1820 * Check for 802.2 encapsulation (EtherTalk phase 2?);
1821 * we check for an Ethernet type field less than
1822 * 1500, which means it's an 802.3 length field.
1823 */
1824 b0 = gen_cmp_gt(OR_LINK, off_linktype, BPF_H, ETHERMTU);
1825 gen_not(b0);
1826
1827 /*
1828 * 802.2-encapsulated ETHERTYPE_ATALK packets are
1829 * SNAP packets with an organization code of
1830 * 0x080007 (Apple, for Appletalk) and a protocol
1831 * type of ETHERTYPE_ATALK (Appletalk).
1832 *
1833 * 802.2-encapsulated ETHERTYPE_AARP packets are
1834 * SNAP packets with an organization code of
1835 * 0x000000 (encapsulated Ethernet) and a protocol
1836 * type of ETHERTYPE_AARP (Appletalk ARP).
1837 */
1838 if (proto == ETHERTYPE_ATALK)
de0d3203 1839 b1 = gen_snap(0x080007, ETHERTYPE_ATALK);
23fa89e6 1840 else /* proto == ETHERTYPE_AARP */
de0d3203 1841 b1 = gen_snap(0x000000, ETHERTYPE_AARP);
23fa89e6
PA
1842 gen_and(b0, b1);
1843
1844 /*
1845 * Check for Ethernet encapsulation (Ethertalk
1846 * phase 1?); we just check for the Ethernet
1847 * protocol type.
1848 */
1849 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32)proto);
1850
1851 gen_or(b0, b1);
1852 return b1;
1853
1854 default:
1855 if (proto <= ETHERMTU) {
1856 /*
1857 * This is an LLC SAP value, so the frames
1858 * that match would be 802.2 frames.
1859 * Check that the frame is an 802.2 frame
1860 * (i.e., that the length/type field is
1861 * a length field, <= ETHERMTU) and
1862 * then check the DSAP.
1863 */
1864 b0 = gen_cmp_gt(OR_LINK, off_linktype, BPF_H, ETHERMTU);
1865 gen_not(b0);
1866 b1 = gen_cmp(OR_LINK, off_linktype + 2, BPF_B,
1867 (bpf_int32)proto);
1868 gen_and(b0, b1);
1869 return b1;
1870 } else {
1871 /*
1872 * This is an Ethernet type, so compare
1873 * the length/type field with it (if
1874 * the frame is an 802.2 frame, the length
1875 * field will be <= ETHERMTU, and, as
1876 * "proto" is > ETHERMTU, this test
1877 * will fail and the frame won't match,
1878 * which is what we want).
1879 */
1880 return gen_cmp(OR_LINK, off_linktype, BPF_H,
1881 (bpf_int32)proto);
1882 }
1883 }
1884}
1885
1886/*
a85e14b0
PA
1887 * "proto" is an Ethernet type value and for IPNET, if it is not IPv4
1888 * or IPv6 then we have an error.
1889 */
1890static struct block *
1891gen_ipnet_linktype(proto)
1892 register int proto;
1893{
1894 switch (proto) {
1895
1896 case ETHERTYPE_IP:
1897 return gen_cmp(OR_LINK, off_linktype, BPF_B,
1898 (bpf_int32)IPH_AF_INET);
1899 /* NOTREACHED */
1900
1901 case ETHERTYPE_IPV6:
1902 return gen_cmp(OR_LINK, off_linktype, BPF_B,
1903 (bpf_int32)IPH_AF_INET6);
1904 /* NOTREACHED */
1905
1906 default:
1907 break;
1908 }
1909
1910 return gen_false();
1911}
1912
1913/*
23fa89e6
PA
1914 * Generate code to match a particular packet type.
1915 *
1916 * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
1917 * value, if <= ETHERMTU. We use that to determine whether to
1918 * match the type field or to check the type field for the special
1919 * LINUX_SLL_P_802_2 value and then do the appropriate test.
1920 */
1921static struct block *
1922gen_linux_sll_linktype(proto)
1923 register int proto;
1924{
1925 struct block *b0, *b1;
1926
1927 switch (proto) {
1928
1929 case LLCSAP_ISONS:
1930 case LLCSAP_IP:
1931 case LLCSAP_NETBEUI:
1932 /*
1933 * OSI protocols and NetBEUI always use 802.2 encapsulation,
1934 * so we check the DSAP and SSAP.
1935 *
1936 * LLCSAP_IP checks for IP-over-802.2, rather
1937 * than IP-over-Ethernet or IP-over-SNAP.
1938 *
1939 * XXX - should we check both the DSAP and the
1940 * SSAP, like this, or should we check just the
1941 * DSAP, as we do for other types <= ETHERMTU
1942 * (i.e., other SAP values)?
1943 */
1944 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_2);
de0d3203 1945 b1 = gen_cmp(OR_MACPL, 0, BPF_H, (bpf_int32)
23fa89e6
PA
1946 ((proto << 8) | proto));
1947 gen_and(b0, b1);
1948 return b1;
1949
1950 case LLCSAP_IPX:
1951 /*
1952 * Ethernet_II frames, which are Ethernet
1953 * frames with a frame type of ETHERTYPE_IPX;
1954 *
1955 * Ethernet_802.3 frames, which have a frame
1956 * type of LINUX_SLL_P_802_3;
1957 *
1958 * Ethernet_802.2 frames, which are 802.3
1959 * frames with an 802.2 LLC header (i.e, have
1960 * a frame type of LINUX_SLL_P_802_2) and
1961 * with the IPX LSAP as the DSAP in the LLC
1962 * header;
1963 *
1964 * Ethernet_SNAP frames, which are 802.3
1965 * frames with an LLC header and a SNAP
1966 * header and with an OUI of 0x000000
1967 * (encapsulated Ethernet) and a protocol
1968 * ID of ETHERTYPE_IPX in the SNAP header.
1969 *
1970 * First, do the checks on LINUX_SLL_P_802_2
1971 * frames; generate the check for either
1972 * Ethernet_802.2 or Ethernet_SNAP frames, and
1973 * then put a check for LINUX_SLL_P_802_2 frames
1974 * before it.
1975 */
de0d3203
PA
1976 b0 = gen_cmp(OR_MACPL, 0, BPF_B, (bpf_int32)LLCSAP_IPX);
1977 b1 = gen_snap(0x000000, ETHERTYPE_IPX);
23fa89e6
PA
1978 gen_or(b0, b1);
1979 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_2);
1980 gen_and(b0, b1);
1981
1982 /*
1983 * Now check for 802.3 frames and OR that with
1984 * the previous test.
1985 */
1986 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_3);
1987 gen_or(b0, b1);
1988
1989 /*
1990 * Now add the check for Ethernet_II frames, and
1991 * do that before checking for the other frame
1992 * types.
1993 */
1994 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H,
1995 (bpf_int32)ETHERTYPE_IPX);
1996 gen_or(b0, b1);
1997 return b1;
1998
1999 case ETHERTYPE_ATALK:
2000 case ETHERTYPE_AARP:
2001 /*
2002 * EtherTalk (AppleTalk protocols on Ethernet link
2003 * layer) may use 802.2 encapsulation.
2004 */
2005
2006 /*
2007 * Check for 802.2 encapsulation (EtherTalk phase 2?);
2008 * we check for the 802.2 protocol type in the
2009 * "Ethernet type" field.
2010 */
2011 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_2);
2012
2013 /*
2014 * 802.2-encapsulated ETHERTYPE_ATALK packets are
2015 * SNAP packets with an organization code of
2016 * 0x080007 (Apple, for Appletalk) and a protocol
2017 * type of ETHERTYPE_ATALK (Appletalk).
2018 *
2019 * 802.2-encapsulated ETHERTYPE_AARP packets are
2020 * SNAP packets with an organization code of
2021 * 0x000000 (encapsulated Ethernet) and a protocol
2022 * type of ETHERTYPE_AARP (Appletalk ARP).
2023 */
2024 if (proto == ETHERTYPE_ATALK)
de0d3203 2025 b1 = gen_snap(0x080007, ETHERTYPE_ATALK);
23fa89e6 2026 else /* proto == ETHERTYPE_AARP */
de0d3203 2027 b1 = gen_snap(0x000000, ETHERTYPE_AARP);
23fa89e6
PA
2028 gen_and(b0, b1);
2029
2030 /*
2031 * Check for Ethernet encapsulation (Ethertalk
2032 * phase 1?); we just check for the Ethernet
2033 * protocol type.
2034 */
2035 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32)proto);
2036
2037 gen_or(b0, b1);
2038 return b1;
2039
2040 default:
2041 if (proto <= ETHERMTU) {
2042 /*
2043 * This is an LLC SAP value, so the frames
2044 * that match would be 802.2 frames.
2045 * Check for the 802.2 protocol type
2046 * in the "Ethernet type" field, and
2047 * then check the DSAP.
2048 */
2049 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H,
2050 LINUX_SLL_P_802_2);
de0d3203 2051 b1 = gen_cmp(OR_LINK, off_macpl, BPF_B,
23fa89e6
PA
2052 (bpf_int32)proto);
2053 gen_and(b0, b1);
2054 return b1;
2055 } else {
2056 /*
2057 * This is an Ethernet type, so compare
2058 * the length/type field with it (if
2059 * the frame is an 802.2 frame, the length
2060 * field will be <= ETHERMTU, and, as
2061 * "proto" is > ETHERMTU, this test
2062 * will fail and the frame won't match,
2063 * which is what we want).
2064 */
2065 return gen_cmp(OR_LINK, off_linktype, BPF_H,
2066 (bpf_int32)proto);
2067 }
2068 }
2069}
2070
de0d3203
PA
2071static struct slist *
2072gen_load_prism_llprefixlen()
23fa89e6
PA
2073{
2074 struct slist *s1, *s2;
de0d3203
PA
2075 struct slist *sjeq_avs_cookie;
2076 struct slist *sjcommon;
2077
2078 /*
2079 * This code is not compatible with the optimizer, as
2080 * we are generating jmp instructions within a normal
2081 * slist of instructions
2082 */
2083 no_optimize = 1;
23fa89e6
PA
2084
2085 /*
de0d3203
PA
2086 * Generate code to load the length of the radio header into
2087 * the register assigned to hold that length, if one has been
2088 * assigned. (If one hasn't been assigned, no code we've
2089 * generated uses that prefix, so we don't need to generate any
2090 * code to load it.)
2091 *
2092 * Some Linux drivers use ARPHRD_IEEE80211_PRISM but sometimes
2093 * or always use the AVS header rather than the Prism header.
2094 * We load a 4-byte big-endian value at the beginning of the
2095 * raw packet data, and see whether, when masked with 0xFFFFF000,
2096 * it's equal to 0x80211000. If so, that indicates that it's
2097 * an AVS header (the masked-out bits are the version number).
2098 * Otherwise, it's a Prism header.
2099 *
2100 * XXX - the Prism header is also, in theory, variable-length,
2101 * but no known software generates headers that aren't 144
2102 * bytes long.
23fa89e6 2103 */
de0d3203
PA
2104 if (reg_off_ll != -1) {
2105 /*
2106 * Load the cookie.
2107 */
2108 s1 = new_stmt(BPF_LD|BPF_W|BPF_ABS);
2109 s1->s.k = 0;
2110
2111 /*
2112 * AND it with 0xFFFFF000.
2113 */
2114 s2 = new_stmt(BPF_ALU|BPF_AND|BPF_K);
2115 s2->s.k = 0xFFFFF000;
2116 sappend(s1, s2);
2117
2118 /*
2119 * Compare with 0x80211000.
2120 */
2121 sjeq_avs_cookie = new_stmt(JMP(BPF_JEQ));
2122 sjeq_avs_cookie->s.k = 0x80211000;
2123 sappend(s1, sjeq_avs_cookie);
2124
2125 /*
2126 * If it's AVS:
2127 *
2128 * The 4 bytes at an offset of 4 from the beginning of
2129 * the AVS header are the length of the AVS header.
2130 * That field is big-endian.
2131 */
2132 s2 = new_stmt(BPF_LD|BPF_W|BPF_ABS);
2133 s2->s.k = 4;
2134 sappend(s1, s2);
2135 sjeq_avs_cookie->s.jt = s2;
2136
2137 /*
2138 * Now jump to the code to allocate a register
2139 * into which to save the header length and
2140 * store the length there. (The "jump always"
2141 * instruction needs to have the k field set;
2142 * it's added to the PC, so, as we're jumping
2143 * over a single instruction, it should be 1.)
2144 */
2145 sjcommon = new_stmt(JMP(BPF_JA));
2146 sjcommon->s.k = 1;
2147 sappend(s1, sjcommon);
2148
2149 /*
2150 * Now for the code that handles the Prism header.
2151 * Just load the length of the Prism header (144)
2152 * into the A register. Have the test for an AVS
2153 * header branch here if we don't have an AVS header.
2154 */
2155 s2 = new_stmt(BPF_LD|BPF_W|BPF_IMM);
2156 s2->s.k = 144;
2157 sappend(s1, s2);
2158 sjeq_avs_cookie->s.jf = s2;
2159
2160 /*
2161 * Now allocate a register to hold that value and store
2162 * it. The code for the AVS header will jump here after
2163 * loading the length of the AVS header.
2164 */
2165 s2 = new_stmt(BPF_ST);
2166 s2->s.k = reg_off_ll;
2167 sappend(s1, s2);
2168 sjcommon->s.jf = s2;
2169
2170 /*
2171 * Now move it into the X register.
2172 */
2173 s2 = new_stmt(BPF_MISC|BPF_TAX);
2174 sappend(s1, s2);
2175
2176 return (s1);
2177 } else
2178 return (NULL);
2179}
2180
2181static struct slist *
2182gen_load_avs_llprefixlen()
2183{
2184 struct slist *s1, *s2;
2185
2186 /*
2187 * Generate code to load the length of the AVS header into
2188 * the register assigned to hold that length, if one has been
2189 * assigned. (If one hasn't been assigned, no code we've
2190 * generated uses that prefix, so we don't need to generate any
2191 * code to load it.)
2192 */
2193 if (reg_off_ll != -1) {
2194 /*
2195 * The 4 bytes at an offset of 4 from the beginning of
2196 * the AVS header are the length of the AVS header.
2197 * That field is big-endian.
2198 */
2199 s1 = new_stmt(BPF_LD|BPF_W|BPF_ABS);
2200 s1->s.k = 4;
2201
2202 /*
2203 * Now allocate a register to hold that value and store
2204 * it.
2205 */
2206 s2 = new_stmt(BPF_ST);
2207 s2->s.k = reg_off_ll;
2208 sappend(s1, s2);
2209
2210 /*
2211 * Now move it into the X register.
2212 */
2213 s2 = new_stmt(BPF_MISC|BPF_TAX);
2214 sappend(s1, s2);
2215
2216 return (s1);
2217 } else
2218 return (NULL);
2219}
2220
2221static struct slist *
2222gen_load_radiotap_llprefixlen()
23fa89e6
PA
2223{
2224 struct slist *s1, *s2;
2225
2226 /*
de0d3203
PA
2227 * Generate code to load the length of the radiotap header into
2228 * the register assigned to hold that length, if one has been
2229 * assigned. (If one hasn't been assigned, no code we've
2230 * generated uses that prefix, so we don't need to generate any
2231 * code to load it.)
23fa89e6 2232 */
de0d3203 2233 if (reg_off_ll != -1) {
23fa89e6
PA
2234 /*
2235 * The 2 bytes at offsets of 2 and 3 from the beginning
2236 * of the radiotap header are the length of the radiotap
2237 * header; unfortunately, it's little-endian, so we have
2238 * to load it a byte at a time and construct the value.
2239 */
2240
2241 /*
2242 * Load the high-order byte, at an offset of 3, shift it
2243 * left a byte, and put the result in the X register.
2244 */
2245 s1 = new_stmt(BPF_LD|BPF_B|BPF_ABS);
2246 s1->s.k = 3;
2247 s2 = new_stmt(BPF_ALU|BPF_LSH|BPF_K);
2248 sappend(s1, s2);
2249 s2->s.k = 8;
2250 s2 = new_stmt(BPF_MISC|BPF_TAX);
2251 sappend(s1, s2);
2252
2253 /*
2254 * Load the next byte, at an offset of 2, and OR the
2255 * value from the X register into it.
2256 */
2257 s2 = new_stmt(BPF_LD|BPF_B|BPF_ABS);
2258 sappend(s1, s2);
2259 s2->s.k = 2;
2260 s2 = new_stmt(BPF_ALU|BPF_OR|BPF_X);
2261 sappend(s1, s2);
2262
2263 /*
2264 * Now allocate a register to hold that value and store
2265 * it.
2266 */
2267 s2 = new_stmt(BPF_ST);
de0d3203 2268 s2->s.k = reg_off_ll;
23fa89e6
PA
2269 sappend(s1, s2);
2270
2271 /*
2272 * Now move it into the X register.
2273 */
2274 s2 = new_stmt(BPF_MISC|BPF_TAX);
2275 sappend(s1, s2);
2276
de0d3203
PA
2277 return (s1);
2278 } else
2279 return (NULL);
23fa89e6
PA
2280}
2281
dfcad8d8
PA
2282/*
2283 * At the moment we treat PPI as normal Radiotap encoded
2284 * packets. The difference is in the function that generates
2285 * the code at the beginning to compute the header length.
2286 * Since this code generator of PPI supports bare 802.11
2287 * encapsulation only (i.e. the encapsulated DLT should be
de0d3203
PA
2288 * DLT_IEEE802_11) we generate code to check for this too;
2289 * that's done in finish_parse().
dfcad8d8 2290 */
de0d3203
PA
2291static struct slist *
2292gen_load_ppi_llprefixlen()
dfcad8d8
PA
2293{
2294 struct slist *s1, *s2;
2295
2296 /*
de0d3203
PA
2297 * Generate code to load the length of the radiotap header
2298 * into the register assigned to hold that length, if one has
2299 * been assigned.
dfcad8d8 2300 */
de0d3203
PA
2301 if (reg_off_ll != -1) {
2302 /*
dfcad8d8
PA
2303 * The 2 bytes at offsets of 2 and 3 from the beginning
2304 * of the radiotap header are the length of the radiotap
2305 * header; unfortunately, it's little-endian, so we have
2306 * to load it a byte at a time and construct the value.
2307 */
2308
2309 /*
2310 * Load the high-order byte, at an offset of 3, shift it
2311 * left a byte, and put the result in the X register.
2312 */
2313 s1 = new_stmt(BPF_LD|BPF_B|BPF_ABS);
2314 s1->s.k = 3;
2315 s2 = new_stmt(BPF_ALU|BPF_LSH|BPF_K);
2316 sappend(s1, s2);
2317 s2->s.k = 8;
2318 s2 = new_stmt(BPF_MISC|BPF_TAX);
2319 sappend(s1, s2);
2320
2321 /*
2322 * Load the next byte, at an offset of 2, and OR the
2323 * value from the X register into it.
2324 */
2325 s2 = new_stmt(BPF_LD|BPF_B|BPF_ABS);
2326 sappend(s1, s2);
2327 s2->s.k = 2;
2328 s2 = new_stmt(BPF_ALU|BPF_OR|BPF_X);
2329 sappend(s1, s2);
2330
2331 /*
2332 * Now allocate a register to hold that value and store
2333 * it.
2334 */
2335 s2 = new_stmt(BPF_ST);
de0d3203 2336 s2->s.k = reg_off_ll;
dfcad8d8
PA
2337 sappend(s1, s2);
2338
2339 /*
2340 * Now move it into the X register.
2341 */
2342 s2 = new_stmt(BPF_MISC|BPF_TAX);
2343 sappend(s1, s2);
2344
de0d3203
PA
2345 return (s1);
2346 } else
2347 return (NULL);
2348}
2349
2350/*
2351 * Load a value relative to the beginning of the link-layer header after the 802.11
2352 * header, i.e. LLC_SNAP.
2353 * The link-layer header doesn't necessarily begin at the beginning
2354 * of the packet data; there might be a variable-length prefix containing
2355 * radio information.
2356 */
2357static struct slist *
2358gen_load_802_11_header_len(struct slist *s, struct slist *snext)
2359{
2360 struct slist *s2;
2361 struct slist *sjset_data_frame_1;
2362 struct slist *sjset_data_frame_2;
2363 struct slist *sjset_qos;
2364 struct slist *sjset_radiotap_flags;
2365 struct slist *sjset_radiotap_tsft;
2366 struct slist *sjset_tsft_datapad, *sjset_notsft_datapad;
2367 struct slist *s_roundup;
2368
2369 if (reg_off_macpl == -1) {
2370 /*
2371 * No register has been assigned to the offset of
2372 * the MAC-layer payload, which means nobody needs
2373 * it; don't bother computing it - just return
2374 * what we already have.
2375 */
2376 return (s);
2377 }
2378
2379 /*
2380 * This code is not compatible with the optimizer, as
2381 * we are generating jmp instructions within a normal
2382 * slist of instructions
2383 */
2384 no_optimize = 1;
2385
2386 /*
2387 * If "s" is non-null, it has code to arrange that the X register
2388 * contains the length of the prefix preceding the link-layer
2389 * header.
2390 *
2391 * Otherwise, the length of the prefix preceding the link-layer
2392 * header is "off_ll".
2393 */
2394 if (s == NULL) {
2395 /*
2396 * There is no variable-length header preceding the
2397 * link-layer header.
2398 *
2399 * Load the length of the fixed-length prefix preceding
2400 * the link-layer header (if any) into the X register,
2401 * and store it in the reg_off_macpl register.
2402 * That length is off_ll.
2403 */
2404 s = new_stmt(BPF_LDX|BPF_IMM);
2405 s->s.k = off_ll;
2406 }
2407
2408 /*
2409 * The X register contains the offset of the beginning of the
2410 * link-layer header; add 24, which is the minimum length
2411 * of the MAC header for a data frame, to that, and store it
2412 * in reg_off_macpl, and then load the Frame Control field,
2413 * which is at the offset in the X register, with an indexed load.
2414 */
2415 s2 = new_stmt(BPF_MISC|BPF_TXA);
2416 sappend(s, s2);
2417 s2 = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
2418 s2->s.k = 24;
2419 sappend(s, s2);
2420 s2 = new_stmt(BPF_ST);
2421 s2->s.k = reg_off_macpl;
2422 sappend(s, s2);
2423
2424 s2 = new_stmt(BPF_LD|BPF_IND|BPF_B);
2425 s2->s.k = 0;
2426 sappend(s, s2);
2427
2428 /*
2429 * Check the Frame Control field to see if this is a data frame;
2430 * a data frame has the 0x08 bit (b3) in that field set and the
2431 * 0x04 bit (b2) clear.
2432 */
2433 sjset_data_frame_1 = new_stmt(JMP(BPF_JSET));
2434 sjset_data_frame_1->s.k = 0x08;
2435 sappend(s, sjset_data_frame_1);
2436
2437 /*
2438 * If b3 is set, test b2, otherwise go to the first statement of
2439 * the rest of the program.
2440 */
2441 sjset_data_frame_1->s.jt = sjset_data_frame_2 = new_stmt(JMP(BPF_JSET));
2442 sjset_data_frame_2->s.k = 0x04;
2443 sappend(s, sjset_data_frame_2);
2444 sjset_data_frame_1->s.jf = snext;
2445
2446 /*
2447 * If b2 is not set, this is a data frame; test the QoS bit.
2448 * Otherwise, go to the first statement of the rest of the
2449 * program.
2450 */
2451 sjset_data_frame_2->s.jt = snext;
2452 sjset_data_frame_2->s.jf = sjset_qos = new_stmt(JMP(BPF_JSET));
2453 sjset_qos->s.k = 0x80; /* QoS bit */
2454 sappend(s, sjset_qos);
2455
2456 /*
2457 * If it's set, add 2 to reg_off_macpl, to skip the QoS
2458 * field.
2459 * Otherwise, go to the first statement of the rest of the
2460 * program.
2461 */
2462 sjset_qos->s.jt = s2 = new_stmt(BPF_LD|BPF_MEM);
2463 s2->s.k = reg_off_macpl;
2464 sappend(s, s2);
2465 s2 = new_stmt(BPF_ALU|BPF_ADD|BPF_IMM);
2466 s2->s.k = 2;
2467 sappend(s, s2);
2468 s2 = new_stmt(BPF_ST);
2469 s2->s.k = reg_off_macpl;
2470 sappend(s, s2);
2471
2472 /*
2473 * If we have a radiotap header, look at it to see whether
2474 * there's Atheros padding between the MAC-layer header
2475 * and the payload.
2476 *
2477 * Note: all of the fields in the radiotap header are
2478 * little-endian, so we byte-swap all of the values
2479 * we test against, as they will be loaded as big-endian
2480 * values.
2481 */
2482 if (linktype == DLT_IEEE802_11_RADIO) {
dfcad8d8 2483 /*
de0d3203
PA
2484 * Is the IEEE80211_RADIOTAP_FLAGS bit (0x0000002) set
2485 * in the presence flag?
dfcad8d8 2486 */
de0d3203
PA
2487 sjset_qos->s.jf = s2 = new_stmt(BPF_LD|BPF_ABS|BPF_W);
2488 s2->s.k = 4;
2489 sappend(s, s2);
2490
2491 sjset_radiotap_flags = new_stmt(JMP(BPF_JSET));
2492 sjset_radiotap_flags->s.k = SWAPLONG(0x00000002);
2493 sappend(s, sjset_radiotap_flags);
dfcad8d8 2494
de0d3203
PA
2495 /*
2496 * If not, skip all of this.
2497 */
2498 sjset_radiotap_flags->s.jf = snext;
2499
2500 /*
2501 * Otherwise, is the IEEE80211_RADIOTAP_TSFT bit set?
2502 */
2503 sjset_radiotap_tsft = sjset_radiotap_flags->s.jt =
2504 new_stmt(JMP(BPF_JSET));
2505 sjset_radiotap_tsft->s.k = SWAPLONG(0x00000001);
2506 sappend(s, sjset_radiotap_tsft);
2507
2508 /*
2509 * If IEEE80211_RADIOTAP_TSFT is set, the flags field is
2510 * at an offset of 16 from the beginning of the raw packet
2511 * data (8 bytes for the radiotap header and 8 bytes for
2512 * the TSFT field).
2513 *
2514 * Test whether the IEEE80211_RADIOTAP_F_DATAPAD bit (0x20)
2515 * is set.
2516 */
2517 sjset_radiotap_tsft->s.jt = s2 = new_stmt(BPF_LD|BPF_ABS|BPF_B);
2518 s2->s.k = 16;
2519 sappend(s, s2);
2520
2521 sjset_tsft_datapad = new_stmt(JMP(BPF_JSET));
2522 sjset_tsft_datapad->s.k = 0x20;
2523 sappend(s, sjset_tsft_datapad);
2524
dfcad8d8 2525 /*
de0d3203
PA
2526 * If IEEE80211_RADIOTAP_TSFT is not set, the flags field is
2527 * at an offset of 8 from the beginning of the raw packet
2528 * data (8 bytes for the radiotap header).
2529 *
2530 * Test whether the IEEE80211_RADIOTAP_F_DATAPAD bit (0x20)
2531 * is set.
dfcad8d8 2532 */
de0d3203
PA
2533 sjset_radiotap_tsft->s.jf = s2 = new_stmt(BPF_LD|BPF_ABS|BPF_B);
2534 s2->s.k = 8;
2535 sappend(s, s2);
2536
2537 sjset_notsft_datapad = new_stmt(JMP(BPF_JSET));
2538 sjset_notsft_datapad->s.k = 0x20;
2539 sappend(s, sjset_notsft_datapad);
2540
2541 /*
2542 * In either case, if IEEE80211_RADIOTAP_F_DATAPAD is
2543 * set, round the length of the 802.11 header to
2544 * a multiple of 4. Do that by adding 3 and then
2545 * dividing by and multiplying by 4, which we do by
2546 * ANDing with ~3.
2547 */
2548 s_roundup = new_stmt(BPF_LD|BPF_MEM);
2549 s_roundup->s.k = reg_off_macpl;
2550 sappend(s, s_roundup);
2551 s2 = new_stmt(BPF_ALU|BPF_ADD|BPF_IMM);
2552 s2->s.k = 3;
2553 sappend(s, s2);
2554 s2 = new_stmt(BPF_ALU|BPF_AND|BPF_IMM);
2555 s2->s.k = ~3;
2556 sappend(s, s2);
2557 s2 = new_stmt(BPF_ST);
2558 s2->s.k = reg_off_macpl;
2559 sappend(s, s2);
dfcad8d8 2560
de0d3203
PA
2561 sjset_tsft_datapad->s.jt = s_roundup;
2562 sjset_tsft_datapad->s.jf = snext;
2563 sjset_notsft_datapad->s.jt = s_roundup;
2564 sjset_notsft_datapad->s.jf = snext;
2565 } else
2566 sjset_qos->s.jf = snext;
2567
2568 return s;
2569}
2570
2571static void
2572insert_compute_vloffsets(b)
2573 struct block *b;
2574{
2575 struct slist *s;
2576
2577 /*
2578 * For link-layer types that have a variable-length header
2579 * preceding the link-layer header, generate code to load
2580 * the offset of the link-layer header into the register
2581 * assigned to that offset, if any.
2582 */
2583 switch (linktype) {
2584
2585 case DLT_PRISM_HEADER:
2586 s = gen_load_prism_llprefixlen();
2587 break;
2588
2589 case DLT_IEEE802_11_RADIO_AVS:
2590 s = gen_load_avs_llprefixlen();
2591 break;
2592
2593 case DLT_IEEE802_11_RADIO:
2594 s = gen_load_radiotap_llprefixlen();
2595 break;
2596
2597 case DLT_PPI:
2598 s = gen_load_ppi_llprefixlen();
2599 break;
2600
2601 default:
2602 s = NULL;
2603 break;
2604 }
2605
2606 /*
2607 * For link-layer types that have a variable-length link-layer
2608 * header, generate code to load the offset of the MAC-layer
2609 * payload into the register assigned to that offset, if any.
2610 */
2611 switch (linktype) {
2612
2613 case DLT_IEEE802_11:
2614 case DLT_PRISM_HEADER:
2615 case DLT_IEEE802_11_RADIO_AVS:
2616 case DLT_IEEE802_11_RADIO:
2617 case DLT_PPI:
2618 s = gen_load_802_11_header_len(s, b->stmts);
2619 break;
2620 }
2621
2622 /*
2623 * If we have any offset-loading code, append all the
2624 * existing statements in the block to those statements,
2625 * and make the resulting list the list of statements
2626 * for the block.
2627 */
2628 if (s != NULL) {
2629 sappend(s, b->stmts);
2630 b->stmts = s;
dfcad8d8
PA
2631 }
2632}
de0d3203 2633
dfcad8d8
PA
2634static struct block *
2635gen_ppi_dlt_check(void)
2636{
2637 struct slist *s_load_dlt;
2638 struct block *b;
2639
2640 if (linktype == DLT_PPI)
2641 {
2642 /* Create the statements that check for the DLT
2643 */
2644 s_load_dlt = new_stmt(BPF_LD|BPF_W|BPF_ABS);
2645 s_load_dlt->s.k = 4;
2646
2647 b = new_block(JMP(BPF_JEQ));
2648
2649 b->stmts = s_load_dlt;
2650 b->s.k = SWAPLONG(DLT_IEEE802_11);
2651 }
2652 else
2653 {
2654 b = NULL;
2655 }
2656
2657 return b;
2658}
23fa89e6 2659
de0d3203
PA
2660static struct slist *
2661gen_prism_llprefixlen(void)
23fa89e6 2662{
de0d3203
PA
2663 struct slist *s;
2664
2665 if (reg_off_ll == -1) {
2666 /*
2667 * We haven't yet assigned a register for the length
2668 * of the radio header; allocate one.
2669 */
2670 reg_off_ll = alloc_reg();
2671 }
23fa89e6 2672
de0d3203
PA
2673 /*
2674 * Load the register containing the radio length
2675 * into the X register.
dfcad8d8 2676 */
de0d3203
PA
2677 s = new_stmt(BPF_LDX|BPF_MEM);
2678 s->s.k = reg_off_ll;
2679 return s;
2680}
dfcad8d8 2681
de0d3203
PA
2682static struct slist *
2683gen_avs_llprefixlen(void)
23fa89e6 2684{
de0d3203 2685 struct slist *s;
dfcad8d8 2686
de0d3203
PA
2687 if (reg_off_ll == -1) {
2688 /*
2689 * We haven't yet assigned a register for the length
2690 * of the AVS header; allocate one.
2691 */
2692 reg_off_ll = alloc_reg();
23fa89e6 2693 }
23fa89e6 2694
de0d3203
PA
2695 /*
2696 * Load the register containing the AVS length
2697 * into the X register.
2698 */
2699 s = new_stmt(BPF_LDX|BPF_MEM);
2700 s->s.k = reg_off_ll;
2701 return s;
2702}
23fa89e6
PA
2703
2704static struct slist *
2705gen_radiotap_llprefixlen(void)
2706{
2707 struct slist *s;
2708
de0d3203 2709 if (reg_off_ll == -1) {
23fa89e6
PA
2710 /*
2711 * We haven't yet assigned a register for the length
2712 * of the radiotap header; allocate one.
2713 */
de0d3203 2714 reg_off_ll = alloc_reg();
23fa89e6
PA
2715 }
2716
2717 /*
2718 * Load the register containing the radiotap length
2719 * into the X register.
2720 */
2721 s = new_stmt(BPF_LDX|BPF_MEM);
de0d3203 2722 s->s.k = reg_off_ll;
23fa89e6
PA
2723 return s;
2724}
2725
dfcad8d8
PA
2726/*
2727 * At the moment we treat PPI as normal Radiotap encoded
2728 * packets. The difference is in the function that generates
2729 * the code at the beginning to compute the header length.
2730 * Since this code generator of PPI supports bare 802.11
2731 * encapsulation only (i.e. the encapsulated DLT should be
2732 * DLT_IEEE802_11) we generate code to check for this too.
2733 */
2734static struct slist *
2735gen_ppi_llprefixlen(void)
2736{
2737 struct slist *s;
2738
de0d3203 2739 if (reg_off_ll == -1) {
dfcad8d8
PA
2740 /*
2741 * We haven't yet assigned a register for the length
2742 * of the radiotap header; allocate one.
2743 */
de0d3203 2744 reg_off_ll = alloc_reg();
dfcad8d8
PA
2745 }
2746
2747 /*
de0d3203 2748 * Load the register containing the PPI length
dfcad8d8
PA
2749 * into the X register.
2750 */
2751 s = new_stmt(BPF_LDX|BPF_MEM);
de0d3203 2752 s->s.k = reg_off_ll;
dfcad8d8
PA
2753 return s;
2754}
2755
23fa89e6
PA
2756/*
2757 * Generate code to compute the link-layer header length, if necessary,
2758 * putting it into the X register, and to return either a pointer to a
2759 * "struct slist" for the list of statements in that code, or NULL if
2760 * no code is necessary.
2761 */
2762static struct slist *
2763gen_llprefixlen(void)
2764{
2765 switch (linktype) {
2766
de0d3203
PA
2767 case DLT_PRISM_HEADER:
2768 return gen_prism_llprefixlen();
2769
2770 case DLT_IEEE802_11_RADIO_AVS:
2771 return gen_avs_llprefixlen();
dfcad8d8 2772
23fa89e6
PA
2773 case DLT_IEEE802_11_RADIO:
2774 return gen_radiotap_llprefixlen();
2775
de0d3203
PA
2776 case DLT_PPI:
2777 return gen_ppi_llprefixlen();
2778
23fa89e6
PA
2779 default:
2780 return NULL;
2781 }
2782}
2783
2784/*
de0d3203
PA
2785 * Generate code to load the register containing the offset of the
2786 * MAC-layer payload into the X register; if no register for that offset
2787 * has been allocated, allocate it first.
2788 */
2789static struct slist *
2790gen_off_macpl(void)
2791{
2792 struct slist *s;
2793
2794 if (off_macpl_is_variable) {
2795 if (reg_off_macpl == -1) {
2796 /*
2797 * We haven't yet assigned a register for the offset
2798 * of the MAC-layer payload; allocate one.
2799 */
2800 reg_off_macpl = alloc_reg();
2801 }
2802
2803 /*
2804 * Load the register containing the offset of the MAC-layer
2805 * payload into the X register.
2806 */
2807 s = new_stmt(BPF_LDX|BPF_MEM);
2808 s->s.k = reg_off_macpl;
2809 return s;
2810 } else {
2811 /*
2812 * That offset isn't variable, so we don't need to
2813 * generate any code.
2814 */
2815 return NULL;
2816 }
2817}
2818
2819/*
2820 * Map an Ethernet type to the equivalent PPP type.
2821 */
2822static int
2823ethertype_to_ppptype(proto)
2824 int proto;
2825{
2826 switch (proto) {
2827
2828 case ETHERTYPE_IP:
2829 proto = PPP_IP;
2830 break;
2831
2832#ifdef INET6
2833 case ETHERTYPE_IPV6:
2834 proto = PPP_IPV6;
2835 break;
2836#endif
2837
2838 case ETHERTYPE_DN:
2839 proto = PPP_DECNET;
2840 break;
2841
2842 case ETHERTYPE_ATALK:
2843 proto = PPP_APPLE;
2844 break;
2845
2846 case ETHERTYPE_NS:
2847 proto = PPP_NS;
2848 break;
2849
2850 case LLCSAP_ISONS:
2851 proto = PPP_OSI;
2852 break;
2853
2854 case LLCSAP_8021D:
2855 /*
2856 * I'm assuming the "Bridging PDU"s that go
2857 * over PPP are Spanning Tree Protocol
2858 * Bridging PDUs.
2859 */
2860 proto = PPP_BRPDU;
2861 break;
2862
2863 case LLCSAP_IPX:
2864 proto = PPP_IPX;
2865 break;
2866 }
2867 return (proto);
2868}
2869
2870/*
23fa89e6
PA
2871 * Generate code to match a particular packet type by matching the
2872 * link-layer type field or fields in the 802.2 LLC header.
2873 *
2874 * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
2875 * value, if <= ETHERMTU.
2876 */
2877static struct block *
2878gen_linktype(proto)
2879 register int proto;
2880{
2881 struct block *b0, *b1, *b2;
2882
2883 /* are we checking MPLS-encapsulated packets? */
2884 if (label_stack_depth > 0) {
2885 switch (proto) {
2886 case ETHERTYPE_IP:
2887 case PPP_IP:
de0d3203 2888 /* FIXME add other L3 proto IDs */
23fa89e6
PA
2889 return gen_mpls_linktype(Q_IP);
2890
2891 case ETHERTYPE_IPV6:
2892 case PPP_IPV6:
de0d3203 2893 /* FIXME add other L3 proto IDs */
23fa89e6
PA
2894 return gen_mpls_linktype(Q_IPV6);
2895
2896 default:
2897 bpf_error("unsupported protocol over mpls");
2898 /* NOTREACHED */
2899 }
2900 }
2901
de0d3203
PA
2902 /*
2903 * Are we testing PPPoE packets?
2904 */
2905 if (is_pppoes) {
2906 /*
2907 * The PPPoE session header is part of the
2908 * MAC-layer payload, so all references
2909 * should be relative to the beginning of
2910 * that payload.
2911 */
2912
2913 /*
2914 * We use Ethernet protocol types inside libpcap;
2915 * map them to the corresponding PPP protocol types.
2916 */
2917 proto = ethertype_to_ppptype(proto);
2918 return gen_cmp(OR_MACPL, off_linktype, BPF_H, (bpf_int32)proto);
2919 }
2920
23fa89e6
PA
2921 switch (linktype) {
2922
2923 case DLT_EN10MB:
a85e14b0
PA
2924 case DLT_NETANALYZER:
2925 case DLT_NETANALYZER_TRANSPARENT:
23fa89e6
PA
2926 return gen_ether_linktype(proto);
2927 /*NOTREACHED*/
2928 break;
2929
2930 case DLT_C_HDLC:
2931 switch (proto) {
2932
2933 case LLCSAP_ISONS:
2934 proto = (proto << 8 | LLCSAP_ISONS);
2935 /* fall through */
2936
2937 default:
2938 return gen_cmp(OR_LINK, off_linktype, BPF_H,
2939 (bpf_int32)proto);
2940 /*NOTREACHED*/
2941 break;
2942 }
2943 break;
2944
23fa89e6 2945 case DLT_IEEE802_11:
de0d3203 2946 case DLT_PRISM_HEADER:
23fa89e6
PA
2947 case DLT_IEEE802_11_RADIO_AVS:
2948 case DLT_IEEE802_11_RADIO:
de0d3203
PA
2949 case DLT_PPI:
2950 /*
2951 * Check that we have a data frame.
2952 */
2953 b0 = gen_check_802_11_data_frame();
2954
2955 /*
2956 * Now check for the specified link-layer type.
2957 */
2958 b1 = gen_llc_linktype(proto);
2959 gen_and(b0, b1);
2960 return b1;
2961 /*NOTREACHED*/
2962 break;
2963
2964 case DLT_FDDI:
2965 /*
2966 * XXX - check for asynchronous frames, as per RFC 1103.
2967 */
2968 return gen_llc_linktype(proto);
2969 /*NOTREACHED*/
2970 break;
2971
2972 case DLT_IEEE802:
2973 /*
2974 * XXX - check for LLC PDUs, as per IEEE 802.5.
2975 */
2976 return gen_llc_linktype(proto);
2977 /*NOTREACHED*/
2978 break;
2979
23fa89e6
PA
2980 case DLT_ATM_RFC1483:
2981 case DLT_ATM_CLIP:
2982 case DLT_IP_OVER_FC:
2983 return gen_llc_linktype(proto);
2984 /*NOTREACHED*/
2985 break;
2986
2987 case DLT_SUNATM:
2988 /*
2989 * If "is_lane" is set, check for a LANE-encapsulated
2990 * version of this protocol, otherwise check for an
2991 * LLC-encapsulated version of this protocol.
2992 *
2993 * We assume LANE means Ethernet, not Token Ring.
2994 */
2995 if (is_lane) {
2996 /*
2997 * Check that the packet doesn't begin with an
2998 * LE Control marker. (We've already generated
2999 * a test for LANE.)
3000 */
3001 b0 = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS, BPF_H,
3002 0xFF00);
3003 gen_not(b0);
3004
3005 /*
3006 * Now generate an Ethernet test.
3007 */
3008 b1 = gen_ether_linktype(proto);
3009 gen_and(b0, b1);
3010 return b1;
3011 } else {
3012 /*
3013 * Check for LLC encapsulation and then check the
3014 * protocol.
3015 */
3016 b0 = gen_atmfield_code(A_PROTOTYPE, PT_LLC, BPF_JEQ, 0);
3017 b1 = gen_llc_linktype(proto);
3018 gen_and(b0, b1);
3019 return b1;
3020 }
3021 /*NOTREACHED*/
3022 break;
3023
3024 case DLT_LINUX_SLL:
3025 return gen_linux_sll_linktype(proto);
3026 /*NOTREACHED*/
3027 break;
3028
3029 case DLT_SLIP:
3030 case DLT_SLIP_BSDOS:
3031 case DLT_RAW:
3032 /*
3033 * These types don't provide any type field; packets
dfcad8d8 3034 * are always IPv4 or IPv6.
23fa89e6
PA
3035 *
3036 * XXX - for IPv4, check for a version number of 4, and,
3037 * for IPv6, check for a version number of 6?
3038 */
3039 switch (proto) {
3040
3041 case ETHERTYPE_IP:
dfcad8d8
PA
3042 /* Check for a version number of 4. */
3043 return gen_mcmp(OR_LINK, 0, BPF_B, 0x40, 0xF0);
23fa89e6
PA
3044#ifdef INET6
3045 case ETHERTYPE_IPV6:
dfcad8d8
PA
3046 /* Check for a version number of 6. */
3047 return gen_mcmp(OR_LINK, 0, BPF_B, 0x60, 0xF0);
23fa89e6 3048#endif
23fa89e6
PA
3049
3050 default:
3051 return gen_false(); /* always false */
3052 }
3053 /*NOTREACHED*/
3054 break;
3055
a85e14b0
PA
3056 case DLT_IPV4:
3057 /*
3058 * Raw IPv4, so no type field.
3059 */
3060 if (proto == ETHERTYPE_IP)
3061 return gen_true(); /* always true */
3062
3063 /* Checking for something other than IPv4; always false */
3064 return gen_false();
3065 /*NOTREACHED*/
3066 break;
3067
3068 case DLT_IPV6:
3069 /*
3070 * Raw IPv6, so no type field.
3071 */
3072#ifdef INET6
3073 if (proto == ETHERTYPE_IPV6)
3074 return gen_true(); /* always true */
3075#endif
3076
3077 /* Checking for something other than IPv6; always false */
3078 return gen_false();
3079 /*NOTREACHED*/
3080 break;
3081
23fa89e6
PA
3082 case DLT_PPP:
3083 case DLT_PPP_PPPD:
3084 case DLT_PPP_SERIAL:
3085 case DLT_PPP_ETHER:
3086 /*
3087 * We use Ethernet protocol types inside libpcap;
3088 * map them to the corresponding PPP protocol types.
3089 */
de0d3203
PA
3090 proto = ethertype_to_ppptype(proto);
3091 return gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32)proto);
3092 /*NOTREACHED*/
23fa89e6
PA
3093 break;
3094
3095 case DLT_PPP_BSDOS:
3096 /*
3097 * We use Ethernet protocol types inside libpcap;
3098 * map them to the corresponding PPP protocol types.
3099 */
3100 switch (proto) {
3101
3102 case ETHERTYPE_IP:
de0d3203
PA
3103 /*
3104 * Also check for Van Jacobson-compressed IP.
3105 * XXX - do this for other forms of PPP?
3106 */
23fa89e6
PA
3107 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, PPP_IP);
3108 b1 = gen_cmp(OR_LINK, off_linktype, BPF_H, PPP_VJC);
3109 gen_or(b0, b1);
3110 b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, PPP_VJNC);
3111 gen_or(b1, b0);
3112 return b0;
3113
de0d3203
PA
3114 default:
3115 proto = ethertype_to_ppptype(proto);
3116 return gen_cmp(OR_LINK, off_linktype, BPF_H,
3117 (bpf_int32)proto);
23fa89e6 3118 }
de0d3203 3119 /*NOTREACHED*/
23fa89e6
PA
3120 break;
3121
3122 case DLT_NULL:
3123 case DLT_LOOP:
3124 case DLT_ENC:
3125 /*
3126 * For DLT_NULL, the link-layer header is a 32-bit
3127 * word containing an AF_ value in *host* byte order,
3128 * and for DLT_ENC, the link-layer header begins
3129 * with a 32-bit work containing an AF_ value in
3130 * host byte order.
3131 *
3132 * In addition, if we're reading a saved capture file,
3133 * the host byte order in the capture may not be the
3134 * same as the host byte order on this machine.
3135 *
3136 * For DLT_LOOP, the link-layer header is a 32-bit
3137 * word containing an AF_ value in *network* byte order.
3138 *
3139 * XXX - AF_ values may, unfortunately, be platform-
3140 * dependent; for example, FreeBSD's AF_INET6 is 24
3141 * whilst NetBSD's and OpenBSD's is 26.
3142 *
3143 * This means that, when reading a capture file, just
3144 * checking for our AF_INET6 value won't work if the
3145 * capture file came from another OS.
3146 */
3147 switch (proto) {
3148
3149 case ETHERTYPE_IP:
3150 proto = AF_INET;
3151 break;
3152
3153#ifdef INET6
3154 case ETHERTYPE_IPV6:
3155 proto = AF_INET6;
3156 break;
3157#endif
3158
3159 default:
3160 /*
3161 * Not a type on which we support filtering.
3162 * XXX - support those that have AF_ values
3163 * #defined on this platform, at least?
3164 */
3165 return gen_false();
3166 }
3167
3168 if (linktype == DLT_NULL || linktype == DLT_ENC) {
3169 /*
3170 * The AF_ value is in host byte order, but
3171 * the BPF interpreter will convert it to
3172 * network byte order.
3173 *
3174 * If this is a save file, and it's from a
3175 * machine with the opposite byte order to
3176 * ours, we byte-swap the AF_ value.
3177 *
3178 * Then we run it through "htonl()", and
3179 * generate code to compare against the result.
3180 */
3181 if (bpf_pcap->sf.rfile != NULL &&
3182 bpf_pcap->sf.swapped)
3183 proto = SWAPLONG(proto);
3184 proto = htonl(proto);
3185 }
3186 return (gen_cmp(OR_LINK, 0, BPF_W, (bpf_int32)proto));
3187
084fe320 3188#ifdef HAVE_NET_PFVAR_H
23fa89e6
PA
3189 case DLT_PFLOG:
3190 /*
3191 * af field is host byte order in contrast to the rest of
3192 * the packet.
3193 */
3194 if (proto == ETHERTYPE_IP)
3195 return (gen_cmp(OR_LINK, offsetof(struct pfloghdr, af),
3196 BPF_B, (bpf_int32)AF_INET));
3197#ifdef INET6
3198 else if (proto == ETHERTYPE_IPV6)
3199 return (gen_cmp(OR_LINK, offsetof(struct pfloghdr, af),
3200 BPF_B, (bpf_int32)AF_INET6));
3201#endif /* INET6 */
3202 else
3203 return gen_false();
3204 /*NOTREACHED*/
3205 break;
084fe320 3206#endif /* HAVE_NET_PFVAR_H */
23fa89e6
PA
3207
3208 case DLT_ARCNET:
3209 case DLT_ARCNET_LINUX:
3210 /*
3211 * XXX should we check for first fragment if the protocol
3212 * uses PHDS?
3213 */
3214 switch (proto) {
3215
3216 default:
3217 return gen_false();
3218
3219#ifdef INET6
3220 case ETHERTYPE_IPV6:
3221 return (gen_cmp(OR_LINK, off_linktype, BPF_B,
3222 (bpf_int32)ARCTYPE_INET6));
3223#endif /* INET6 */
3224
3225 case ETHERTYPE_IP:
3226 b0 = gen_cmp(OR_LINK, off_linktype, BPF_B,
3227 (bpf_int32)ARCTYPE_IP);
3228 b1 = gen_cmp(OR_LINK, off_linktype, BPF_B,
3229 (bpf_int32)ARCTYPE_IP_OLD);
3230 gen_or(b0, b1);
3231 return (b1);
3232
3233 case ETHERTYPE_ARP:
3234 b0 = gen_cmp(OR_LINK, off_linktype, BPF_B,
3235 (bpf_int32)ARCTYPE_ARP);
3236 b1 = gen_cmp(OR_LINK, off_linktype, BPF_B,
3237 (bpf_int32)ARCTYPE_ARP_OLD);
3238 gen_or(b0, b1);
3239 return (b1);
3240
3241 case ETHERTYPE_REVARP:
3242 return (gen_cmp(OR_LINK, off_linktype, BPF_B,
3243 (bpf_int32)ARCTYPE_REVARP));
3244
3245 case ETHERTYPE_ATALK:
3246 return (gen_cmp(OR_LINK, off_linktype, BPF_B,
3247 (bpf_int32)ARCTYPE_ATALK));
3248 }
3249 /*NOTREACHED*/
3250 break;
3251
3252 case DLT_LTALK:
3253 switch (proto) {
3254 case ETHERTYPE_ATALK:
3255 return gen_true();
3256 default:
3257 return gen_false();
3258 }
3259 /*NOTREACHED*/
3260 break;
3261
3262 case DLT_FRELAY:
3263 /*
3264 * XXX - assumes a 2-byte Frame Relay header with
3265 * DLCI and flags. What if the address is longer?
3266 */
3267 switch (proto) {
3268
3269 case ETHERTYPE_IP:
3270 /*
3271 * Check for the special NLPID for IP.
3272 */
3273 return gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | 0xcc);
3274
3275#ifdef INET6
3276 case ETHERTYPE_IPV6:
3277 /*
3278 * Check for the special NLPID for IPv6.
3279 */
3280 return gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | 0x8e);
3281#endif
3282
3283 case LLCSAP_ISONS:
3284 /*
3285 * Check for several OSI protocols.
3286 *
3287 * Frame Relay packets typically have an OSI
3288 * NLPID at the beginning; we check for each
3289 * of them.
3290 *
3291 * What we check for is the NLPID and a frame
3292 * control field of UI, i.e. 0x03 followed
3293 * by the NLPID.
3294 */
3295 b0 = gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | ISO8473_CLNP);
3296 b1 = gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | ISO9542_ESIS);
3297 b2 = gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | ISO10589_ISIS);
3298 gen_or(b1, b2);
3299 gen_or(b0, b2);
3300 return b2;
3301
3302 default:
3303 return gen_false();
3304 }
3305 /*NOTREACHED*/
3306 break;
3307
de0d3203
PA
3308 case DLT_MFR:
3309 bpf_error("Multi-link Frame Relay link-layer type filtering not implemented");
3310
23fa89e6
PA
3311 case DLT_JUNIPER_MFR:
3312 case DLT_JUNIPER_MLFR:
3313 case DLT_JUNIPER_MLPPP:
3314 case DLT_JUNIPER_ATM1:
3315 case DLT_JUNIPER_ATM2:
3316 case DLT_JUNIPER_PPPOE:
3317 case DLT_JUNIPER_PPPOE_ATM:
3318 case DLT_JUNIPER_GGSN:
3319 case DLT_JUNIPER_ES:
3320 case DLT_JUNIPER_MONITOR:
3321 case DLT_JUNIPER_SERVICES:
3322 case DLT_JUNIPER_ETHER:
3323 case DLT_JUNIPER_PPP:
3324 case DLT_JUNIPER_FRELAY:
3325 case DLT_JUNIPER_CHDLC:
dfcad8d8 3326 case DLT_JUNIPER_VP:
de0d3203
PA
3327 case DLT_JUNIPER_ST:
3328 case DLT_JUNIPER_ISM:
a85e14b0
PA
3329 case DLT_JUNIPER_VS:
3330 case DLT_JUNIPER_SRX_E2E:
3331 case DLT_JUNIPER_FIBRECHANNEL:
3332 case DLT_JUNIPER_ATM_CEMIC:
3333
23fa89e6
PA
3334 /* just lets verify the magic number for now -
3335 * on ATM we may have up to 6 different encapsulations on the wire
3336 * and need a lot of heuristics to figure out that the payload
3337 * might be;
3338 *
3339 * FIXME encapsulation specific BPF_ filters
3340 */
3341 return gen_mcmp(OR_LINK, 0, BPF_W, 0x4d474300, 0xffffff00); /* compare the magic number */
3342
a85e14b0
PA
3343 case DLT_IPNET:
3344 return gen_ipnet_linktype(proto);
3345
23fa89e6
PA
3346 case DLT_LINUX_IRDA:
3347 bpf_error("IrDA link-layer type filtering not implemented");
3348
3349 case DLT_DOCSIS:
3350 bpf_error("DOCSIS link-layer type filtering not implemented");
3351
de0d3203
PA
3352 case DLT_MTP2:
3353 case DLT_MTP2_WITH_PHDR:
3354 bpf_error("MTP2 link-layer type filtering not implemented");
3355
3356 case DLT_ERF:
3357 bpf_error("ERF link-layer type filtering not implemented");
3358
3359#ifdef DLT_PFSYNC
3360 case DLT_PFSYNC:
3361 bpf_error("PFSYNC link-layer type filtering not implemented");
3362#endif
3363
23fa89e6
PA
3364 case DLT_LINUX_LAPD:
3365 bpf_error("LAPD link-layer type filtering not implemented");
de0d3203
PA
3366
3367 case DLT_USB:
3368 case DLT_USB_LINUX:
a85e14b0 3369 case DLT_USB_LINUX_MMAPPED:
de0d3203
PA
3370 bpf_error("USB link-layer type filtering not implemented");
3371
3372 case DLT_BLUETOOTH_HCI_H4:
3373 case DLT_BLUETOOTH_HCI_H4_WITH_PHDR:
3374 bpf_error("Bluetooth link-layer type filtering not implemented");
3375
3376 case DLT_CAN20B:
a85e14b0
PA
3377 case DLT_CAN_SOCKETCAN:
3378 bpf_error("CAN link-layer type filtering not implemented");
de0d3203
PA
3379
3380 case DLT_IEEE802_15_4:
3381 case DLT_IEEE802_15_4_LINUX:
3382 case DLT_IEEE802_15_4_NONASK_PHY:
a85e14b0 3383 case DLT_IEEE802_15_4_NOFCS:
de0d3203
PA
3384 bpf_error("IEEE 802.15.4 link-layer type filtering not implemented");
3385
3386 case DLT_IEEE802_16_MAC_CPS_RADIO:
3387 bpf_error("IEEE 802.16 link-layer type filtering not implemented");
3388
3389 case DLT_SITA:
3390 bpf_error("SITA link-layer type filtering not implemented");
3391
3392 case DLT_RAIF1:
3393 bpf_error("RAIF1 link-layer type filtering not implemented");
3394
3395 case DLT_IPMB:
3396 bpf_error("IPMB link-layer type filtering not implemented");
3397
3398 case DLT_AX25_KISS:
3399 bpf_error("AX.25 link-layer type filtering not implemented");
23fa89e6
PA
3400 }
3401
3402 /*
3403 * All the types that have no encapsulation should either be
3404 * handled as DLT_SLIP, DLT_SLIP_BSDOS, and DLT_RAW are, if
3405 * all packets are IP packets, or should be handled in some
3406 * special case, if none of them are (if some are and some
3407 * aren't, the lack of encapsulation is a problem, as we'd
3408 * have to find some other way of determining the packet type).
3409 *
3410 * Therefore, if "off_linktype" is -1, there's an error.
3411 */
3412 if (off_linktype == (u_int)-1)
3413 abort();
3414
3415 /*
3416 * Any type not handled above should always have an Ethernet
de0d3203 3417 * type at an offset of "off_linktype".
23fa89e6
PA
3418 */
3419 return gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32)proto);
3420}
3421
3422/*
3423 * Check for an LLC SNAP packet with a given organization code and
3424 * protocol type; we check the entire contents of the 802.2 LLC and
3425 * snap headers, checking for DSAP and SSAP of SNAP and a control
3426 * field of 0x03 in the LLC header, and for the specified organization
3427 * code and protocol type in the SNAP header.
3428 */
3429static struct block *
de0d3203 3430gen_snap(orgcode, ptype)
23fa89e6
PA
3431 bpf_u_int32 orgcode;
3432 bpf_u_int32 ptype;
23fa89e6
PA
3433{
3434 u_char snapblock[8];
3435
3436 snapblock[0] = LLCSAP_SNAP; /* DSAP = SNAP */
3437 snapblock[1] = LLCSAP_SNAP; /* SSAP = SNAP */
3438 snapblock[2] = 0x03; /* control = UI */
3439 snapblock[3] = (orgcode >> 16); /* upper 8 bits of organization code */
3440 snapblock[4] = (orgcode >> 8); /* middle 8 bits of organization code */
3441 snapblock[5] = (orgcode >> 0); /* lower 8 bits of organization code */
3442 snapblock[6] = (ptype >> 8); /* upper 8 bits of protocol type */
3443 snapblock[7] = (ptype >> 0); /* lower 8 bits of protocol type */
de0d3203 3444 return gen_bcmp(OR_MACPL, 0, 8, snapblock);
23fa89e6
PA
3445}
3446
3447/*
3448 * Generate code to match a particular packet type, for link-layer types
3449 * using 802.2 LLC headers.
3450 *
3451 * This is *NOT* used for Ethernet; "gen_ether_linktype()" is used
3452 * for that - it handles the D/I/X Ethernet vs. 802.3+802.2 issues.
3453 *
3454 * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
3455 * value, if <= ETHERMTU. We use that to determine whether to
3456 * match the DSAP or both DSAP and LSAP or to check the OUI and
3457 * protocol ID in a SNAP header.
3458 */
3459static struct block *
3460gen_llc_linktype(proto)
3461 int proto;
3462{
3463 /*
3464 * XXX - handle token-ring variable-length header.
3465 */
3466 switch (proto) {
3467
3468 case LLCSAP_IP:
3469 case LLCSAP_ISONS:
3470 case LLCSAP_NETBEUI:
3471 /*
3472 * XXX - should we check both the DSAP and the
3473 * SSAP, like this, or should we check just the
3474 * DSAP, as we do for other types <= ETHERMTU
3475 * (i.e., other SAP values)?
3476 */
de0d3203 3477 return gen_cmp(OR_MACPL, 0, BPF_H, (bpf_u_int32)
23fa89e6
PA
3478 ((proto << 8) | proto));
3479
3480 case LLCSAP_IPX:
3481 /*
3482 * XXX - are there ever SNAP frames for IPX on
3483 * non-Ethernet 802.x networks?
3484 */
de0d3203 3485 return gen_cmp(OR_MACPL, 0, BPF_B,
23fa89e6
PA
3486 (bpf_int32)LLCSAP_IPX);
3487
3488 case ETHERTYPE_ATALK:
3489 /*
3490 * 802.2-encapsulated ETHERTYPE_ATALK packets are
3491 * SNAP packets with an organization code of
3492 * 0x080007 (Apple, for Appletalk) and a protocol
3493 * type of ETHERTYPE_ATALK (Appletalk).
3494 *
3495 * XXX - check for an organization code of
3496 * encapsulated Ethernet as well?
3497 */
de0d3203 3498 return gen_snap(0x080007, ETHERTYPE_ATALK);
23fa89e6
PA
3499
3500 default:
3501 /*
3502 * XXX - we don't have to check for IPX 802.3
3503 * here, but should we check for the IPX Ethertype?
3504 */
3505 if (proto <= ETHERMTU) {
3506 /*
3507 * This is an LLC SAP value, so check
3508 * the DSAP.
3509 */
de0d3203 3510 return gen_cmp(OR_MACPL, 0, BPF_B, (bpf_int32)proto);
23fa89e6
PA
3511 } else {
3512 /*
3513 * This is an Ethernet type; we assume that it's
3514 * unlikely that it'll appear in the right place
3515 * at random, and therefore check only the
3516 * location that would hold the Ethernet type
3517 * in a SNAP frame with an organization code of
3518 * 0x000000 (encapsulated Ethernet).
3519 *
3520 * XXX - if we were to check for the SNAP DSAP and
3521 * LSAP, as per XXX, and were also to check for an
3522 * organization code of 0x000000 (encapsulated
3523 * Ethernet), we'd do
3524 *
de0d3203 3525 * return gen_snap(0x000000, proto);
23fa89e6
PA
3526 *
3527 * here; for now, we don't, as per the above.
3528 * I don't know whether it's worth the extra CPU
3529 * time to do the right check or not.
3530 */
de0d3203 3531 return gen_cmp(OR_MACPL, 6, BPF_H, (bpf_int32)proto);
23fa89e6
PA
3532 }
3533 }
3534}
3535
3536static struct block *
3537gen_hostop(addr, mask, dir, proto, src_off, dst_off)
3538 bpf_u_int32 addr;
3539 bpf_u_int32 mask;
3540 int dir, proto;
3541 u_int src_off, dst_off;
3542{
3543 struct block *b0, *b1;
3544 u_int offset;
3545
3546 switch (dir) {
3547
3548 case Q_SRC:
3549 offset = src_off;
3550 break;
3551
3552 case Q_DST:
3553 offset = dst_off;
3554 break;
3555
3556 case Q_AND:
3557 b0 = gen_hostop(addr, mask, Q_SRC, proto, src_off, dst_off);
3558 b1 = gen_hostop(addr, mask, Q_DST, proto, src_off, dst_off);
3559 gen_and(b0, b1);
3560 return b1;
3561
3562 case Q_OR:
3563 case Q_DEFAULT:
3564 b0 = gen_hostop(addr, mask, Q_SRC, proto, src_off, dst_off);
3565 b1 = gen_hostop(addr, mask, Q_DST, proto, src_off, dst_off);
3566 gen_or(b0, b1);
3567 return b1;
3568
3569 default:
3570 abort();
3571 }
3572 b0 = gen_linktype(proto);
3573 b1 = gen_mcmp(OR_NET, offset, BPF_W, (bpf_int32)addr, mask);
3574 gen_and(b0, b1);
3575 return b1;
3576}
3577
3578#ifdef INET6
3579static struct block *
3580gen_hostop6(addr, mask, dir, proto, src_off, dst_off)
3581 struct in6_addr *addr;
3582 struct in6_addr *mask;
3583 int dir, proto;
3584 u_int src_off, dst_off;
3585{
3586 struct block *b0, *b1;
3587 u_int offset;
3588 u_int32_t *a, *m;
3589
3590 switch (dir) {
3591
3592 case Q_SRC:
3593 offset = src_off;
3594 break;
3595
3596 case Q_DST:
3597 offset = dst_off;
3598 break;
3599
3600 case Q_AND:
3601 b0 = gen_hostop6(addr, mask, Q_SRC, proto, src_off, dst_off);
3602 b1 = gen_hostop6(addr, mask, Q_DST, proto, src_off, dst_off);
3603 gen_and(b0, b1);
3604 return b1;
3605
3606 case Q_OR:
3607 case Q_DEFAULT:
3608 b0 = gen_hostop6(addr, mask, Q_SRC, proto, src_off, dst_off);
3609 b1 = gen_hostop6(addr, mask, Q_DST, proto, src_off, dst_off);
3610 gen_or(b0, b1);
3611 return b1;
3612
3613 default:
3614 abort();
3615 }
3616 /* this order is important */
3617 a = (u_int32_t *)addr;
3618 m = (u_int32_t *)mask;
3619 b1 = gen_mcmp(OR_NET, offset + 12, BPF_W, ntohl(a[3]), ntohl(m[3]));
3620 b0 = gen_mcmp(OR_NET, offset + 8, BPF_W, ntohl(a[2]), ntohl(m[2]));
3621 gen_and(b0, b1);
3622 b0 = gen_mcmp(OR_NET, offset + 4, BPF_W, ntohl(a[1]), ntohl(m[1]));
3623 gen_and(b0, b1);
3624 b0 = gen_mcmp(OR_NET, offset + 0, BPF_W, ntohl(a[0]), ntohl(m[0]));
3625 gen_and(b0, b1);
3626 b0 = gen_linktype(proto);
3627 gen_and(b0, b1);
3628 return b1;
3629}
3630#endif /*INET6*/
3631
3632static struct block *
3633gen_ehostop(eaddr, dir)
3634 register const u_char *eaddr;
3635 register int dir;
3636{
3637 register struct block *b0, *b1;
3638
3639 switch (dir) {
3640 case Q_SRC:
3641 return gen_bcmp(OR_LINK, off_mac + 6, 6, eaddr);
3642
3643 case Q_DST:
3644 return gen_bcmp(OR_LINK, off_mac + 0, 6, eaddr);
3645
3646 case Q_AND:
3647 b0 = gen_ehostop(eaddr, Q_SRC);
3648 b1 = gen_ehostop(eaddr, Q_DST);
3649 gen_and(b0, b1);
3650 return b1;
3651
3652 case Q_DEFAULT:
3653 case Q_OR:
3654 b0 = gen_ehostop(eaddr, Q_SRC);
3655 b1 = gen_ehostop(eaddr, Q_DST);
3656 gen_or(b0, b1);
3657 return b1;
a85e14b0
PA
3658
3659 case Q_ADDR1:
3660 bpf_error("'addr1' is only supported on 802.11 with 802.11 headers");
3661 break;
3662
3663 case Q_ADDR2:
3664 bpf_error("'addr2' is only supported on 802.11 with 802.11 headers");
3665 break;
3666
3667 case Q_ADDR3:
3668 bpf_error("'addr3' is only supported on 802.11 with 802.11 headers");
3669 break;
3670
3671 case Q_ADDR4:
3672 bpf_error("'addr4' is only supported on 802.11 with 802.11 headers");
3673 break;
3674
3675 case Q_RA:
3676 bpf_error("'ra' is only supported on 802.11 with 802.11 headers");
3677 break;
3678
3679 case Q_TA:
3680 bpf_error("'ta' is only supported on 802.11 with 802.11 headers");
3681 break;
23fa89e6
PA
3682 }
3683 abort();
3684 /* NOTREACHED */
3685}
3686
3687/*
3688 * Like gen_ehostop, but for DLT_FDDI
3689 */
3690static struct block *
3691gen_fhostop(eaddr, dir)
3692 register const u_char *eaddr;
3693 register int dir;
3694{
3695 struct block *b0, *b1;
3696
3697 switch (dir) {
3698 case Q_SRC:
3699#ifdef PCAP_FDDIPAD
3700 return gen_bcmp(OR_LINK, 6 + 1 + pcap_fddipad, 6, eaddr);
3701#else
3702 return gen_bcmp(OR_LINK, 6 + 1, 6, eaddr);
3703#endif
3704
3705 case Q_DST:
3706#ifdef PCAP_FDDIPAD
3707 return gen_bcmp(OR_LINK, 0 + 1 + pcap_fddipad, 6, eaddr);
3708#else
3709 return gen_bcmp(OR_LINK, 0 + 1, 6, eaddr);
3710#endif
3711
3712 case Q_AND:
3713 b0 = gen_fhostop(eaddr, Q_SRC);
3714 b1 = gen_fhostop(eaddr, Q_DST);
3715 gen_and(b0, b1);
3716 return b1;
3717
3718 case Q_DEFAULT:
3719 case Q_OR:
3720 b0 = gen_fhostop(eaddr, Q_SRC);
3721 b1 = gen_fhostop(eaddr, Q_DST);
3722 gen_or(b0, b1);
3723 return b1;
a85e14b0
PA
3724
3725 case Q_ADDR1:
3726 bpf_error("'addr1' is only supported on 802.11");
3727 break;
3728
3729 case Q_ADDR2:
3730 bpf_error("'addr2' is only supported on 802.11");
3731 break;
3732
3733 case Q_ADDR3:
3734 bpf_error("'addr3' is only supported on 802.11");
3735 break;
3736
3737 case Q_ADDR4:
3738 bpf_error("'addr4' is only supported on 802.11");
3739 break;
3740
3741 case Q_RA:
3742 bpf_error("'ra' is only supported on 802.11");
3743 break;
3744
3745 case Q_TA:
3746 bpf_error("'ta' is only supported on 802.11");
3747 break;
23fa89e6
PA
3748 }
3749 abort();
3750 /* NOTREACHED */
3751}
3752
3753/*
3754 * Like gen_ehostop, but for DLT_IEEE802 (Token Ring)
3755 */
3756static struct block *
3757gen_thostop(eaddr, dir)
3758 register const u_char *eaddr;
3759 register int dir;
3760{
3761 register struct block *b0, *b1;
3762
3763 switch (dir) {
3764 case Q_SRC:
3765 return gen_bcmp(OR_LINK, 8, 6, eaddr);
3766
3767 case Q_DST:
3768 return gen_bcmp(OR_LINK, 2, 6, eaddr);
3769
3770 case Q_AND:
3771 b0 = gen_thostop(eaddr, Q_SRC);
3772 b1 = gen_thostop(eaddr, Q_DST);
3773 gen_and(b0, b1);
3774 return b1;
3775
3776 case Q_DEFAULT:
3777 case Q_OR:
3778 b0 = gen_thostop(eaddr, Q_SRC);
3779 b1 = gen_thostop(eaddr, Q_DST);
3780 gen_or(b0, b1);
3781 return b1;
a85e14b0
PA
3782
3783 case Q_ADDR1:
3784 bpf_error("'addr1' is only supported on 802.11");
3785 break;
3786
3787 case Q_ADDR2:
3788 bpf_error("'addr2' is only supported on 802.11");
3789 break;
3790
3791 case Q_ADDR3:
3792 bpf_error("'addr3' is only supported on 802.11");
3793 break;
3794
3795 case Q_ADDR4:
3796 bpf_error("'addr4' is only supported on 802.11");
3797 break;
3798
3799 case Q_RA:
3800 bpf_error("'ra' is only supported on 802.11");
3801 break;
3802
3803 case Q_TA:
3804 bpf_error("'ta' is only supported on 802.11");
3805 break;
23fa89e6
PA
3806 }
3807 abort();
3808 /* NOTREACHED */
3809}
3810
3811/*
de0d3203
PA
3812 * Like gen_ehostop, but for DLT_IEEE802_11 (802.11 wireless LAN) and
3813 * various 802.11 + radio headers.
23fa89e6
PA
3814 */
3815static struct block *
3816gen_wlanhostop(eaddr, dir)
3817 register const u_char *eaddr;
3818 register int dir;
3819{
3820 register struct block *b0, *b1, *b2;
3821 register struct slist *s;
3822
de0d3203
PA
3823#ifdef ENABLE_WLAN_FILTERING_PATCH
3824 /*
3825 * TODO GV 20070613
3826 * We need to disable the optimizer because the optimizer is buggy
3827 * and wipes out some LD instructions generated by the below
3828 * code to validate the Frame Control bits
3829 */
3830 no_optimize = 1;
3831#endif /* ENABLE_WLAN_FILTERING_PATCH */
3832
23fa89e6
PA
3833 switch (dir) {
3834 case Q_SRC:
3835 /*
3836 * Oh, yuk.
3837 *
3838 * For control frames, there is no SA.
3839 *
3840 * For management frames, SA is at an
3841 * offset of 10 from the beginning of
3842 * the packet.
3843 *
3844 * For data frames, SA is at an offset
3845 * of 10 from the beginning of the packet
3846 * if From DS is clear, at an offset of
3847 * 16 from the beginning of the packet
3848 * if From DS is set and To DS is clear,
3849 * and an offset of 24 from the beginning
3850 * of the packet if From DS is set and To DS
3851 * is set.
3852 */
3853
3854 /*
3855 * Generate the tests to be done for data frames
3856 * with From DS set.
3857 *
3858 * First, check for To DS set, i.e. check "link[1] & 0x01".
3859 */
3860 s = gen_load_a(OR_LINK, 1, BPF_B);
3861 b1 = new_block(JMP(BPF_JSET));
3862 b1->s.k = 0x01; /* To DS */
3863 b1->stmts = s;
3864
3865 /*
3866 * If To DS is set, the SA is at 24.
3867 */
3868 b0 = gen_bcmp(OR_LINK, 24, 6, eaddr);
3869 gen_and(b1, b0);
3870
3871 /*
3872 * Now, check for To DS not set, i.e. check
3873 * "!(link[1] & 0x01)".
3874 */
3875 s = gen_load_a(OR_LINK, 1, BPF_B);
3876 b2 = new_block(JMP(BPF_JSET));
3877 b2->s.k = 0x01; /* To DS */
3878 b2->stmts = s;
3879 gen_not(b2);
3880
3881 /*
3882 * If To DS is not set, the SA is at 16.
3883 */
3884 b1 = gen_bcmp(OR_LINK, 16, 6, eaddr);
3885 gen_and(b2, b1);
3886
3887 /*
3888 * Now OR together the last two checks. That gives
3889 * the complete set of checks for data frames with
3890 * From DS set.
3891 */
3892 gen_or(b1, b0);
3893
3894 /*
3895 * Now check for From DS being set, and AND that with
3896 * the ORed-together checks.
3897 */
3898 s = gen_load_a(OR_LINK, 1, BPF_B);
3899 b1 = new_block(JMP(BPF_JSET));
3900 b1->s.k = 0x02; /* From DS */
3901 b1->stmts = s;
3902 gen_and(b1, b0);
3903
3904 /*
3905 * Now check for data frames with From DS not set.
3906 */
3907 s = gen_load_a(OR_LINK, 1, BPF_B);
3908 b2 = new_block(JMP(BPF_JSET));
3909 b2->s.k = 0x02; /* From DS */
3910 b2->stmts = s;
3911 gen_not(b2);
3912
3913 /*
3914 * If From DS isn't set, the SA is at 10.
3915 */
3916 b1 = gen_bcmp(OR_LINK, 10, 6, eaddr);
3917 gen_and(b2, b1);
3918
3919 /*
3920 * Now OR together the checks for data frames with
3921 * From DS not set and for data frames with From DS
3922 * set; that gives the checks done for data frames.
3923 */
3924 gen_or(b1, b0);
3925
3926 /*
3927 * Now check for a data frame.
3928 * I.e, check "link[0] & 0x08".
3929 */
de0d3203 3930 s = gen_load_a(OR_LINK, 0, BPF_B);
23fa89e6
PA
3931 b1 = new_block(JMP(BPF_JSET));
3932 b1->s.k = 0x08;
3933 b1->stmts = s;
3934
3935 /*
3936 * AND that with the checks done for data frames.
3937 */
3938 gen_and(b1, b0);
3939
3940 /*
3941 * If the high-order bit of the type value is 0, this
3942 * is a management frame.
3943 * I.e, check "!(link[0] & 0x08)".
3944 */
3945 s = gen_load_a(OR_LINK, 0, BPF_B);
3946 b2 = new_block(JMP(BPF_JSET));