1/* $NetBSD: gencode.c,v 1.11 2018/09/03 15:26:43 christos Exp $ */
2
3/*#define CHASE_CHAIN*/
4/*
5 * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998
6 * The Regents of the University of California. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that: (1) source code distributions
10 * retain the above copyright notice and this paragraph in its entirety, (2)
11 * distributions including binary code include the above copyright notice and
12 * this paragraph in its entirety in the documentation or other materials
13 * provided with the distribution, and (3) all advertising materials mentioning
14 * features or use of this software display the following acknowledgement:
15 * ``This product includes software developed by the University of California,
16 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
17 * the University nor the names of its contributors may be used to endorse
18 * or promote products derived from this software without specific prior
19 * written permission.
20 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
21 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
22 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
23 */
24
25#include <sys/cdefs.h>
26__RCSID("$NetBSD: gencode.c,v 1.11 2018/09/03 15:26:43 christos Exp $");
27
28#ifdef HAVE_CONFIG_H
29#include <config.h>
30#endif
31
32#include <pcap-types.h>
33#ifdef _WIN32
34 #include <ws2tcpip.h>
35#else
36 #include <sys/socket.h>
37
38 #ifdef __NetBSD__
39 #include <sys/param.h>
40 #endif
41
42 #include <netinet/in.h>
43 #include <arpa/inet.h>
44#endif /* _WIN32 */
45
46#include <stdlib.h>
47#include <string.h>
48#include <memory.h>
49#include <setjmp.h>
50#include <stdarg.h>
51
52#ifdef MSDOS
53#include "pcap-dos.h"
54#endif
55
56#include "pcap-int.h"
57
58#include "ethertype.h"
59#include "nlpid.h"
60#include "llc.h"
61#include "gencode.h"
62#include "ieee80211.h"
63#include "atmuni31.h"
64#include "sunatmpos.h"
65#include "ppp.h"
66#include "pcap/sll.h"
67#include "pcap/ipnet.h"
68#include "arcnet.h"
69
70#include "grammar.h"
71#include "scanner.h"
72
73#if defined(linux) && defined(PF_PACKET) && defined(SO_ATTACH_FILTER)
74#include <linux/types.h>
75#include <linux/if_packet.h>
76#include <linux/filter.h>
77#endif
78
79#ifdef HAVE_NET_PFVAR_H
80#include <sys/socket.h>
81#include <net/if.h>
82#include <net/pfvar.h>
83#include <net/if_pflog.h>
84#endif
85
86#ifndef offsetof
87#define offsetof(s, e) ((size_t)&((s *)0)->e)
88#endif
89
90#ifdef _WIN32
91 #ifdef INET6
92 #if defined(__MINGW32__) && defined(DEFINE_ADDITIONAL_IPV6_STUFF)
93/* IPv6 address */
94struct in6_addr
95 {
96 union
97 {
98 uint8_t u6_addr8[16];
99 uint16_t u6_addr16[8];
100 uint32_t u6_addr32[4];
101 } in6_u;
102#define s6_addr in6_u.u6_addr8
103#define s6_addr16 in6_u.u6_addr16
104#define s6_addr32 in6_u.u6_addr32
105#define s6_addr64 in6_u.u6_addr64
106 };
107
108typedef unsigned short sa_family_t;
109
110#define __SOCKADDR_COMMON(sa_prefix) \
111 sa_family_t sa_prefix##family
112
113/* Ditto, for IPv6. */
114struct sockaddr_in6
115 {
116 __SOCKADDR_COMMON (sin6_);
117 uint16_t sin6_port; /* Transport layer port # */
118 uint32_t sin6_flowinfo; /* IPv6 flow information */
119 struct in6_addr sin6_addr; /* IPv6 address */
120 };
121
122 #ifndef EAI_ADDRFAMILY
123struct addrinfo {
124 int ai_flags; /* AI_PASSIVE, AI_CANONNAME */
125 int ai_family; /* PF_xxx */
126 int ai_socktype; /* SOCK_xxx */
127 int ai_protocol; /* 0 or IPPROTO_xxx for IPv4 and IPv6 */
128 size_t ai_addrlen; /* length of ai_addr */
129 char *ai_canonname; /* canonical name for hostname */
130 struct sockaddr *ai_addr; /* binary address */
131 struct addrinfo *ai_next; /* next structure in linked list */
132};
133 #endif /* EAI_ADDRFAMILY */
134 #endif /* defined(__MINGW32__) && defined(DEFINE_ADDITIONAL_IPV6_STUFF) */
135 #endif /* INET6 */
136#else /* _WIN32 */
137 #include <netdb.h> /* for "struct addrinfo" */
138#endif /* _WIN32 */
139#include <pcap/namedb.h>
140
141#include "nametoaddr.h"
142
143#define ETHERMTU 1500
144
145#ifndef ETHERTYPE_TEB
146#define ETHERTYPE_TEB 0x6558
147#endif
148
149#ifndef IPPROTO_HOPOPTS
150#define IPPROTO_HOPOPTS 0
151#endif
152#ifndef IPPROTO_ROUTING
153#define IPPROTO_ROUTING 43
154#endif
155#ifndef IPPROTO_FRAGMENT
156#define IPPROTO_FRAGMENT 44
157#endif
158#ifndef IPPROTO_DSTOPTS
159#define IPPROTO_DSTOPTS 60
160#endif
161#ifndef IPPROTO_SCTP
162#define IPPROTO_SCTP 132
163#endif
164
165#define GENEVE_PORT 6081
166
167#ifdef HAVE_OS_PROTO_H
168#include "os-proto.h"
169#endif
170
171#define JMP(c) ((c)|BPF_JMP|BPF_K)
172
173/*
174 * "Push" the current value of the link-layer header type and link-layer
175 * header offset onto a "stack", and set a new value. (It's not a
176 * full-blown stack; we keep only the top two items.)
177 */
178#define PUSH_LINKHDR(cs, new_linktype, new_is_variable, new_constant_part, new_reg) \
179{ \
180 (cs)->prevlinktype = (cs)->linktype; \
181 (cs)->off_prevlinkhdr = (cs)->off_linkhdr; \
182 (cs)->linktype = (new_linktype); \
183 (cs)->off_linkhdr.is_variable = (new_is_variable); \
184 (cs)->off_linkhdr.constant_part = (new_constant_part); \
185 (cs)->off_linkhdr.reg = (new_reg); \
186 (cs)->is_geneve = 0; \
187}
188
189/*
190 * Offset "not set" value.
191 */
192#define OFFSET_NOT_SET 0xffffffffU
193
194/*
195 * Absolute offsets, which are offsets from the beginning of the raw
196 * packet data, are, in the general case, the sum of a variable value
197 * and a constant value; the variable value may be absent, in which
198 * case the offset is only the constant value, and the constant value
199 * may be zero, in which case the offset is only the variable value.
200 *
201 * bpf_abs_offset is a structure containing all that information:
202 *
203 * is_variable is 1 if there's a variable part.
204 *
205 * constant_part is the constant part of the value, possibly zero;
206 *
207 * if is_variable is 1, reg is the register number for a register
208 * containing the variable value if the register has been assigned,
209 * and -1 otherwise.
210 */
211typedef struct {
212 int is_variable;
213 u_int constant_part;
214 int reg;
215} bpf_abs_offset;
216
217/*
218 * Value passed to gen_load_a() to indicate what the offset argument
219 * is relative to the beginning of.
220 */
221enum e_offrel {
222 OR_PACKET, /* full packet data */
223 OR_LINKHDR, /* link-layer header */
224 OR_PREVLINKHDR, /* previous link-layer header */
225 OR_LLC, /* 802.2 LLC header */
226 OR_PREVMPLSHDR, /* previous MPLS header */
227 OR_LINKTYPE, /* link-layer type */
228 OR_LINKPL, /* link-layer payload */
229 OR_LINKPL_NOSNAP, /* link-layer payload, with no SNAP header at the link layer */
230 OR_TRAN_IPV4, /* transport-layer header, with IPv4 network layer */
231 OR_TRAN_IPV6 /* transport-layer header, with IPv6 network layer */
232};
233
234/*
235 * We divy out chunks of memory rather than call malloc each time so
236 * we don't have to worry about leaking memory. It's probably
237 * not a big deal if all this memory was wasted but if this ever
238 * goes into a library that would probably not be a good idea.
239 *
240 * XXX - this *is* in a library....
241 */
242#define NCHUNKS 16
243#define CHUNK0SIZE 1024
244struct chunk {
245 size_t n_left;
246 void *m;
247};
248
249/* Code generator state */
250
251struct _compiler_state {
252 jmp_buf top_ctx;
253 pcap_t *bpf_pcap;
254
255 struct icode ic;
256
257 int snaplen;
258
259 int linktype;
260 int prevlinktype;
261 int outermostlinktype;
262
263 bpf_u_int32 netmask;
264 int no_optimize;
265
266 /* Hack for handling VLAN and MPLS stacks. */
267 u_int label_stack_depth;
268 u_int vlan_stack_depth;
269
270 /* XXX */
271 u_int pcap_fddipad;
272
273 /*
274 * As errors are handled by a longjmp, anything allocated must
275 * be freed in the longjmp handler, so it must be reachable
276 * from that handler.
277 *
278 * One thing that's allocated is the result of pcap_nametoaddrinfo();
279 * it must be freed with freeaddrinfo(). This variable points to
280 * any addrinfo structure that would need to be freed.
281 */
282 struct addrinfo *ai;
283
284 /*
285 * Various code constructs need to know the layout of the packet.
286 * These values give the necessary offsets from the beginning
287 * of the packet data.
288 */
289
290 /*
291 * Absolute offset of the beginning of the link-layer header.
292 */
293 bpf_abs_offset off_linkhdr;
294
295 /*
296 * If we're checking a link-layer header for a packet encapsulated
297 * in another protocol layer, this is the equivalent information
298 * for the previous layers' link-layer header from the beginning
299 * of the raw packet data.
300 */
301 bpf_abs_offset off_prevlinkhdr;
302
303 /*
304 * This is the equivalent information for the outermost layers'
305 * link-layer header.
306 */
307 bpf_abs_offset off_outermostlinkhdr;
308
309 /*
310 * Absolute offset of the beginning of the link-layer payload.
311 */
312 bpf_abs_offset off_linkpl;
313
314 /*
315 * "off_linktype" is the offset to information in the link-layer
316 * header giving the packet type. This is an absolute offset
317 * from the beginning of the packet.
318 *
319 * For Ethernet, it's the offset of the Ethernet type field; this
320 * means that it must have a value that skips VLAN tags.
321 *
322 * For link-layer types that always use 802.2 headers, it's the
323 * offset of the LLC header; this means that it must have a value
324 * that skips VLAN tags.
325 *
326 * For PPP, it's the offset of the PPP type field.
327 *
328 * For Cisco HDLC, it's the offset of the CHDLC type field.
329 *
330 * For BSD loopback, it's the offset of the AF_ value.
331 *
332 * For Linux cooked sockets, it's the offset of the type field.
333 *
334 * off_linktype.constant_part is set to OFFSET_NOT_SET for no
335 * encapsulation, in which case, IP is assumed.
336 */
337 bpf_abs_offset off_linktype;
338
339 /*
340 * TRUE if the link layer includes an ATM pseudo-header.
341 */
342 int is_atm;
343
344 /*
345 * TRUE if "geneve" appeared in the filter; it causes us to
346 * generate code that checks for a Geneve header and assume
347 * that later filters apply to the encapsulated payload.
348 */
349 int is_geneve;
350
351 /*
352 * TRUE if we need variable length part of VLAN offset
353 */
354 int is_vlan_vloffset;
355
356 /*
357 * These are offsets for the ATM pseudo-header.
358 */
359 u_int off_vpi;
360 u_int off_vci;
361 u_int off_proto;
362
363 /*
364 * These are offsets for the MTP2 fields.
365 */
366 u_int off_li;
367 u_int off_li_hsl;
368
369 /*
370 * These are offsets for the MTP3 fields.
371 */
372 u_int off_sio;
373 u_int off_opc;
374 u_int off_dpc;
375 u_int off_sls;
376
377 /*
378 * This is the offset of the first byte after the ATM pseudo_header,
379 * or -1 if there is no ATM pseudo-header.
380 */
381 u_int off_payload;
382
383 /*
384 * These are offsets to the beginning of the network-layer header.
385 * They are relative to the beginning of the link-layer payload
386 * (i.e., they don't include off_linkhdr.constant_part or
387 * off_linkpl.constant_part).
388 *
389 * If the link layer never uses 802.2 LLC:
390 *
391 * "off_nl" and "off_nl_nosnap" are the same.
392 *
393 * If the link layer always uses 802.2 LLC:
394 *
395 * "off_nl" is the offset if there's a SNAP header following
396 * the 802.2 header;
397 *
398 * "off_nl_nosnap" is the offset if there's no SNAP header.
399 *
400 * If the link layer is Ethernet:
401 *
402 * "off_nl" is the offset if the packet is an Ethernet II packet
403 * (we assume no 802.3+802.2+SNAP);
404 *
405 * "off_nl_nosnap" is the offset if the packet is an 802.3 packet
406 * with an 802.2 header following it.
407 */
408 u_int off_nl;
409 u_int off_nl_nosnap;
410
411 /*
412 * Here we handle simple allocation of the scratch registers.
413 * If too many registers are alloc'd, the allocator punts.
414 */
415 int regused[BPF_MEMWORDS];
416 int curreg;
417
418 /*
419 * Memory chunks.
420 */
421 struct chunk chunks[NCHUNKS];
422 int cur_chunk;
423};
424
425void PCAP_NORETURN
426bpf_syntax_error(compiler_state_t *cstate, const char *msg)
427{
428 bpf_error(cstate, "syntax error in filter expression: %s", msg);
429 /* NOTREACHED */
430}
431
432/* VARARGS */
433void PCAP_NORETURN
434bpf_error(compiler_state_t *cstate, const char *fmt, ...)
435{
436 va_list ap;
437
438 va_start(ap, fmt);
439 if (cstate->bpf_pcap != NULL)
440 (void)pcap_vsnprintf(pcap_geterr(cstate->bpf_pcap),
441 PCAP_ERRBUF_SIZE, fmt, ap);
442 va_end(ap);
443 longjmp(cstate->top_ctx, 1);
444 /* NOTREACHED */
445}
446
447static void init_linktype(compiler_state_t *, pcap_t *);
448
449static void init_regs(compiler_state_t *);
450static int alloc_reg(compiler_state_t *);
451static void free_reg(compiler_state_t *, int);
452
453static void initchunks(compiler_state_t *cstate);
454static void *newchunk(compiler_state_t *cstate, size_t);
455static void freechunks(compiler_state_t *cstate);
456static inline struct block *new_block(compiler_state_t *cstate, int);
457static inline struct slist *new_stmt(compiler_state_t *cstate, int);
458static struct block *gen_retblk(compiler_state_t *cstate, int);
459static inline void syntax(compiler_state_t *cstate);
460
461static void backpatch(struct block *, struct block *);
462static void merge(struct block *, struct block *);
463static struct block *gen_cmp(compiler_state_t *, enum e_offrel, u_int,
464 u_int, bpf_int32);
465static struct block *gen_cmp_gt(compiler_state_t *, enum e_offrel, u_int,
466 u_int, bpf_int32);
467static struct block *gen_cmp_ge(compiler_state_t *, enum e_offrel, u_int,
468 u_int, bpf_int32);
469static struct block *gen_cmp_lt(compiler_state_t *, enum e_offrel, u_int,
470 u_int, bpf_int32);
471static struct block *gen_cmp_le(compiler_state_t *, enum e_offrel, u_int,
472 u_int, bpf_int32);
473static struct block *gen_mcmp(compiler_state_t *, enum e_offrel, u_int,
474 u_int, bpf_int32, bpf_u_int32);
475static struct block *gen_bcmp(compiler_state_t *, enum e_offrel, u_int,
476 u_int, const u_char *);
477static struct block *gen_ncmp(compiler_state_t *, enum e_offrel, bpf_u_int32,
478 bpf_u_int32, bpf_u_int32, bpf_u_int32, int, bpf_int32);
479static struct slist *gen_load_absoffsetrel(compiler_state_t *, bpf_abs_offset *,
480 u_int, u_int);
481static struct slist *gen_load_a(compiler_state_t *, enum e_offrel, u_int,
482 u_int);
483static struct slist *gen_loadx_iphdrlen(compiler_state_t *);
484static struct block *gen_uncond(compiler_state_t *, int);
485static inline struct block *gen_true(compiler_state_t *);
486static inline struct block *gen_false(compiler_state_t *);
487static struct block *gen_ether_linktype(compiler_state_t *, int);
488static struct block *gen_ipnet_linktype(compiler_state_t *, int);
489static struct block *gen_linux_sll_linktype(compiler_state_t *, int);
490static struct slist *gen_load_prism_llprefixlen(compiler_state_t *);
491static struct slist *gen_load_avs_llprefixlen(compiler_state_t *);
492static struct slist *gen_load_radiotap_llprefixlen(compiler_state_t *);
493static struct slist *gen_load_ppi_llprefixlen(compiler_state_t *);
494static void insert_compute_vloffsets(compiler_state_t *, struct block *);
495static struct slist *gen_abs_offset_varpart(compiler_state_t *,
496 bpf_abs_offset *);
497static int ethertype_to_ppptype(int);
498static struct block *gen_linktype(compiler_state_t *, int);
499static struct block *gen_snap(compiler_state_t *, bpf_u_int32, bpf_u_int32);
500static struct block *gen_llc_linktype(compiler_state_t *, int);
501static struct block *gen_hostop(compiler_state_t *, bpf_u_int32, bpf_u_int32,
502 int, int, u_int, u_int);
503#ifdef INET6
504static struct block *gen_hostop6(compiler_state_t *, struct in6_addr *,
505 struct in6_addr *, int, int, u_int, u_int);
506#endif
507static struct block *gen_ahostop(compiler_state_t *, const u_char *, int);
508static struct block *gen_ehostop(compiler_state_t *, const u_char *, int);
509static struct block *gen_fhostop(compiler_state_t *, const u_char *, int);
510static struct block *gen_thostop(compiler_state_t *, const u_char *, int);
511static struct block *gen_wlanhostop(compiler_state_t *, const u_char *, int);
512static struct block *gen_ipfchostop(compiler_state_t *, const u_char *, int);
513static struct block *gen_dnhostop(compiler_state_t *, bpf_u_int32, int);
514static struct block *gen_mpls_linktype(compiler_state_t *, int);
515static struct block *gen_host(compiler_state_t *, bpf_u_int32, bpf_u_int32,
516 int, int, int);
517#ifdef INET6
518static struct block *gen_host6(compiler_state_t *, struct in6_addr *,
519 struct in6_addr *, int, int, int);
520#endif
521#ifndef INET6
522static struct block *gen_gateway(compiler_state_t *, const u_char *,
523 struct addrinfo *, int, int);
524#endif
525static struct block *gen_ipfrag(compiler_state_t *);
526static struct block *gen_portatom(compiler_state_t *, int, bpf_int32);
527static struct block *gen_portrangeatom(compiler_state_t *, int, bpf_int32,
528 bpf_int32);
529static struct block *gen_portatom6(compiler_state_t *, int, bpf_int32);
530static struct block *gen_portrangeatom6(compiler_state_t *, int, bpf_int32,
531 bpf_int32);
532struct block *gen_portop(compiler_state_t *, int, int, int);
533static struct block *gen_port(compiler_state_t *, int, int, int);
534struct block *gen_portrangeop(compiler_state_t *, int, int, int, int);
535static struct block *gen_portrange(compiler_state_t *, int, int, int, int);
536struct block *gen_portop6(compiler_state_t *, int, int, int);
537static struct block *gen_port6(compiler_state_t *, int, int, int);
538struct block *gen_portrangeop6(compiler_state_t *, int, int, int, int);
539static struct block *gen_portrange6(compiler_state_t *, int, int, int, int);
540static int lookup_proto(compiler_state_t *, const char *, int);
541static struct block *gen_protochain(compiler_state_t *, int, int, int);
542static struct block *gen_proto(compiler_state_t *, int, int, int);
543static struct slist *xfer_to_x(compiler_state_t *, struct arth *);
544static struct slist *xfer_to_a(compiler_state_t *, struct arth *);
545static struct block *gen_mac_multicast(compiler_state_t *, int);
546static struct block *gen_len(compiler_state_t *, int, int);
547static struct block *gen_check_802_11_data_frame(compiler_state_t *);
548static struct block *gen_geneve_ll_check(compiler_state_t *cstate);
549
550static struct block *gen_ppi_dlt_check(compiler_state_t *);
551static struct block *gen_msg_abbrev(compiler_state_t *, int type);
552
553static void
554initchunks(compiler_state_t *cstate)
555{
556 int i;
557
558 for (i = 0; i < NCHUNKS; i++) {
559 cstate->chunks[i].n_left = 0;
560 cstate->chunks[i].m = NULL;
561 }
562 cstate->cur_chunk = 0;
563}
564
565static void *
566newchunk(compiler_state_t *cstate, size_t n)
567{
568 struct chunk *cp;
569 int k;
570 size_t size;
571
572#ifndef __NetBSD__
573 /* XXX Round up to nearest long. */
574 n = (n + sizeof(long) - 1) & ~(sizeof(long) - 1);
575#else
576 /* XXX Round up to structure boundary. */
577 n = ALIGN(n);
578#endif
579
580 cp = &cstate->chunks[cstate->cur_chunk];
581 if (n > cp->n_left) {
582 ++cp;
583 k = ++cstate->cur_chunk;
584 if (k >= NCHUNKS)
585 bpf_error(cstate, "out of memory");
586 size = CHUNK0SIZE << k;
587 cp->m = (void *)malloc(size);
588 if (cp->m == NULL)
589 bpf_error(cstate, "out of memory");
590 memset((char *)cp->m, 0, size);
591 cp->n_left = size;
592 if (n > size)
593 bpf_error(cstate, "out of memory");
594 }
595 cp->n_left -= n;
596 return (void *)((char *)cp->m + cp->n_left);
597}
598
599static void
600freechunks(compiler_state_t *cstate)
601{
602 int i;
603
604 for (i = 0; i < NCHUNKS; ++i)
605 if (cstate->chunks[i].m != NULL)
606 free(cstate->chunks[i].m);
607}
608
609/*
610 * A strdup whose allocations are freed after code generation is over.
611 */
612char *
613sdup(compiler_state_t *cstate, const char *s)
614{
615 size_t n = strlen(s) + 1;
616 char *cp = newchunk(cstate, n);
617
618 strlcpy(cp, s, n);
619 return (cp);
620}
621
622static inline struct block *
623new_block(compiler_state_t *cstate, int code)
624{
625 struct block *p;
626
627 p = (struct block *)newchunk(cstate, sizeof(*p));
628 p->s.code = code;
629 p->head = p;
630
631 return p;
632}
633
634static inline struct slist *
635new_stmt(compiler_state_t *cstate, int code)
636{
637 struct slist *p;
638
639 p = (struct slist *)newchunk(cstate, sizeof(*p));
640 p->s.code = code;
641
642 return p;
643}
644
645static struct block *
646gen_retblk(compiler_state_t *cstate, int v)
647{
648 struct block *b = new_block(cstate, BPF_RET|BPF_K);
649
650 b->s.k = v;
651 return b;
652}
653
654static inline PCAP_NORETURN_DEF void
655syntax(compiler_state_t *cstate)
656{
657 bpf_error(cstate, "syntax error in filter expression");
658}
659
660int
661pcap_compile(pcap_t *p, struct bpf_program *program,
662 const char *buf, int optimize, bpf_u_int32 mask)
663{
664#ifdef _WIN32
665 static int done = 0;
666#endif
667 compiler_state_t cstate;
668 const char * volatile xbuf = buf;
669 yyscan_t scanner = NULL;
670 volatile YY_BUFFER_STATE in_buffer = NULL;
671 u_int len;
672 int rc;
673
674 /*
675 * If this pcap_t hasn't been activated, it doesn't have a
676 * link-layer type, so we can't use it.
677 */
678 if (!p->activated) {
679 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
680 "not-yet-activated pcap_t passed to pcap_compile");
681 return (-1);
682 }
683
684#ifdef _WIN32
685 if (!done)
686 pcap_wsockinit();
687 done = 1;
688#endif
689
690#ifdef ENABLE_REMOTE
691 /*
692 * If the device on which we're capturing need to be notified
693 * that a new filter is being compiled, do so.
694 *
695 * This allows them to save a copy of it, in case, for example,
696 * they're implementing a form of remote packet capture, and
697 * want the remote machine to filter out the packets in which
698 * it's sending the packets it's captured.
699 *
700 * XXX - the fact that we happen to be compiling a filter
701 * doesn't necessarily mean we'll be installing it as the
702 * filter for this pcap_t; we might be running it from userland
703 * on captured packets to do packet classification. We really
704 * need a better way of handling this, but this is all that
705 * the WinPcap code did.
706 */
707 if (p->save_current_filter_op != NULL)
708 (p->save_current_filter_op)(p, buf);
709#endif
710
711 initchunks(&cstate);
712 cstate.no_optimize = 0;
713#ifdef INET6
714 cstate.ai = NULL;
715#endif
716 cstate.ic.root = NULL;
717 cstate.ic.cur_mark = 0;
718 cstate.bpf_pcap = p;
719 init_regs(&cstate);
720
721 if (setjmp(cstate.top_ctx)) {
722#ifdef INET6
723 if (cstate.ai != NULL)
724 freeaddrinfo(cstate.ai);
725#endif
726 rc = -1;
727 goto quit;
728 }
729
730 cstate.netmask = mask;
731
732 cstate.snaplen = pcap_snapshot(p);
733 if (cstate.snaplen == 0) {
734 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
735 "snaplen of 0 rejects all packets");
736 rc = -1;
737 goto quit;
738 }
739
740 if (pcap_lex_init(&scanner) != 0)
741 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
742 errno, "can't initialize scanner");
743 in_buffer = pcap__scan_string(xbuf ? xbuf : "", scanner);
744
745 /*
746 * Associate the compiler state with the lexical analyzer
747 * state.
748 */
749 pcap_set_extra(&cstate, scanner);
750
751 init_linktype(&cstate, p);
752 (void)pcap_parse(scanner, &cstate);
753
754 if (cstate.ic.root == NULL)
755 cstate.ic.root = gen_retblk(&cstate, cstate.snaplen);
756
757 if (optimize && !cstate.no_optimize) {
758 bpf_optimize(&cstate, &cstate.ic);
759 if (cstate.ic.root == NULL ||
760 (cstate.ic.root->s.code == (BPF_RET|BPF_K) && cstate.ic.root->s.k == 0))
761 bpf_error(&cstate, "expression rejects all packets");
762 }
763 program->bf_insns = icode_to_fcode(&cstate, &cstate.ic, cstate.ic.root, &len);
764 program->bf_len = len;
765
766 rc = 0; /* We're all okay */
767
768quit:
769 /*
770 * Clean up everything for the lexical analyzer.
771 */
772 if (in_buffer != NULL)
773 pcap__delete_buffer(in_buffer, scanner);
774 if (scanner != NULL)
775 pcap_lex_destroy(scanner);
776
777 /*
778 * Clean up our own allocated memory.
779 */
780 freechunks(&cstate);
781
782 return (rc);
783}
784
785/*
786 * entry point for using the compiler with no pcap open
787 * pass in all the stuff that is needed explicitly instead.
788 */
789int
790pcap_compile_nopcap(int snaplen_arg, int linktype_arg,
791 struct bpf_program *program,
792 const char *buf, int optimize, bpf_u_int32 mask)
793{
794 pcap_t *p;
795 int ret;
796
797 p = pcap_open_dead(linktype_arg, snaplen_arg);
798 if (p == NULL)
799 return (-1);
800 ret = pcap_compile(p, program, buf, optimize, mask);
801 pcap_close(p);
802 return (ret);
803}
804
805/*
806 * Clean up a "struct bpf_program" by freeing all the memory allocated
807 * in it.
808 */
809void
810pcap_freecode(struct bpf_program *program)
811{
812 program->bf_len = 0;
813 if (program->bf_insns != NULL) {
814 free((char *)program->bf_insns);
815 program->bf_insns = NULL;
816 }
817}
818
819/*
820 * Backpatch the blocks in 'list' to 'target'. The 'sense' field indicates
821 * which of the jt and jf fields has been resolved and which is a pointer
822 * back to another unresolved block (or nil). At least one of the fields
823 * in each block is already resolved.
824 */
825static void
826backpatch(struct block *list, struct block *target)
827{
828 struct block *next;
829
830 while (list) {
831 if (!list->sense) {
832 next = JT(list);
833 JT(list) = target;
834 } else {
835 next = JF(list);
836 JF(list) = target;
837 }
838 list = next;
839 }
840}
841
842/*
843 * Merge the lists in b0 and b1, using the 'sense' field to indicate
844 * which of jt and jf is the link.
845 */
846static void
847merge(struct block *b0, struct block *b1)
848{
849 register struct block **p = &b0;
850
851 /* Find end of list. */
852 while (*p)
853 p = !((*p)->sense) ? &JT(*p) : &JF(*p);
854
855 /* Concatenate the lists. */
856 *p = b1;
857}
858
859void
860finish_parse(compiler_state_t *cstate, struct block *p)
861{
862 struct block *ppi_dlt_check;
863
864 /*
865 * Insert before the statements of the first (root) block any
866 * statements needed to load the lengths of any variable-length
867 * headers into registers.
868 *
869 * XXX - a fancier strategy would be to insert those before the
870 * statements of all blocks that use those lengths and that
871 * have no predecessors that use them, so that we only compute
872 * the lengths if we need them. There might be even better
873 * approaches than that.
874 *
875 * However, those strategies would be more complicated, and
876 * as we don't generate code to compute a length if the
877 * program has no tests that use the length, and as most
878 * tests will probably use those lengths, we would just
879 * postpone computing the lengths so that it's not done
880 * for tests that fail early, and it's not clear that's
881 * worth the effort.
882 */
883 insert_compute_vloffsets(cstate, p->head);
884
885 /*
886 * For DLT_PPI captures, generate a check of the per-packet
887 * DLT value to make sure it's DLT_IEEE802_11.
888 *
889 * XXX - TurboCap cards use DLT_PPI for Ethernet.
890 * Can we just define some DLT_ETHERNET_WITH_PHDR pseudo-header
891 * with appropriate Ethernet information and use that rather
892 * than using something such as DLT_PPI where you don't know
893 * the link-layer header type until runtime, which, in the
894 * general case, would force us to generate both Ethernet *and*
895 * 802.11 code (*and* anything else for which PPI is used)
896 * and choose between them early in the BPF program?
897 */
898 ppi_dlt_check = gen_ppi_dlt_check(cstate);
899 if (ppi_dlt_check != NULL)
900 gen_and(ppi_dlt_check, p);
901
902 backpatch(p, gen_retblk(cstate, cstate->snaplen));
903 p->sense = !p->sense;
904 backpatch(p, gen_retblk(cstate, 0));
905 cstate->ic.root = p->head;
906}
907
908void
909gen_and(struct block *b0, struct block *b1)
910{
911 backpatch(b0, b1->head);
912 b0->sense = !b0->sense;
913 b1->sense = !b1->sense;
914 merge(b1, b0);
915 b1->sense = !b1->sense;
916 b1->head = b0->head;
917}
918
919void
920gen_or(struct block *b0, struct block *b1)
921{
922 b0->sense = !b0->sense;
923 backpatch(b0, b1->head);
924 b0->sense = !b0->sense;
925 merge(b1, b0);
926 b1->head = b0->head;
927}
928
929void
930gen_not(struct block *b)
931{
932 b->sense = !b->sense;
933}
934
935static struct block *
936gen_cmp(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
937 u_int size, bpf_int32 v)
938{
939 return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JEQ, 0, v);
940}
941
942static struct block *
943gen_cmp_gt(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
944 u_int size, bpf_int32 v)
945{
946 return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGT, 0, v);
947}
948
949static struct block *
950gen_cmp_ge(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
951 u_int size, bpf_int32 v)
952{
953 return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGE, 0, v);
954}
955
956static struct block *
957gen_cmp_lt(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
958 u_int size, bpf_int32 v)
959{
960 return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGE, 1, v);
961}
962
963static struct block *
964gen_cmp_le(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
965 u_int size, bpf_int32 v)
966{
967 return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGT, 1, v);
968}
969
970static struct block *
971gen_mcmp(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
972 u_int size, bpf_int32 v, bpf_u_int32 mask)
973{
974 return gen_ncmp(cstate, offrel, offset, size, mask, BPF_JEQ, 0, v);
975}
976
977static struct block *
978gen_bcmp(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
979 u_int size, const u_char *v)
980{
981 register struct block *b, *tmp;
982
983 b = NULL;
984 while (size >= 4) {
985 register const u_char *p = &v[size - 4];
986 bpf_int32 w = ((bpf_int32)p[0] << 24) |
987 ((bpf_int32)p[1] << 16) | ((bpf_int32)p[2] << 8) | p[3];
988
989 tmp = gen_cmp(cstate, offrel, offset + size - 4, BPF_W, w);
990 if (b != NULL)
991 gen_and(b, tmp);
992 b = tmp;
993 size -= 4;
994 }
995 while (size >= 2) {
996 register const u_char *p = &v[size - 2];
997 bpf_int32 w = ((bpf_int32)p[0] << 8) | p[1];
998
999 tmp = gen_cmp(cstate, offrel, offset + size - 2, BPF_H, w);
1000 if (b != NULL)
1001 gen_and(b, tmp);
1002 b = tmp;
1003 size -= 2;
1004 }
1005 if (size > 0) {
1006 tmp = gen_cmp(cstate, offrel, offset, BPF_B, (bpf_int32)v[0]);
1007 if (b != NULL)
1008 gen_and(b, tmp);
1009 b = tmp;
1010 }
1011 return b;
1012}
1013
1014/*
1015 * AND the field of size "size" at offset "offset" relative to the header
1016 * specified by "offrel" with "mask", and compare it with the value "v"
1017 * with the test specified by "jtype"; if "reverse" is true, the test
1018 * should test the opposite of "jtype".
1019 */
1020static struct block *
1021gen_ncmp(compiler_state_t *cstate, enum e_offrel offrel, bpf_u_int32 offset,
1022 bpf_u_int32 size, bpf_u_int32 mask, bpf_u_int32 jtype, int reverse,
1023 bpf_int32 v)
1024{
1025 struct slist *s, *s2;
1026 struct block *b;
1027
1028 s = gen_load_a(cstate, offrel, offset, size);
1029
1030 if (mask != 0xffffffff) {
1031 s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
1032 s2->s.k = mask;
1033 sappend(s, s2);
1034 }
1035
1036 b = new_block(cstate, JMP(jtype));
1037 b->stmts = s;
1038 b->s.k = v;
1039 if (reverse && (jtype == BPF_JGT || jtype == BPF_JGE))
1040 gen_not(b);
1041 return b;
1042}
1043
1044static void
1045init_linktype(compiler_state_t *cstate, pcap_t *p)
1046{
1047 cstate->pcap_fddipad = p->fddipad;
1048
1049 /*
1050 * We start out with only one link-layer header.
1051 */
1052 cstate->outermostlinktype = pcap_datalink(p);
1053 cstate->off_outermostlinkhdr.constant_part = 0;
1054 cstate->off_outermostlinkhdr.is_variable = 0;
1055 cstate->off_outermostlinkhdr.reg = -1;
1056
1057 cstate->prevlinktype = cstate->outermostlinktype;
1058 cstate->off_prevlinkhdr.constant_part = 0;
1059 cstate->off_prevlinkhdr.is_variable = 0;
1060 cstate->off_prevlinkhdr.reg = -1;
1061
1062 cstate->linktype = cstate->outermostlinktype;
1063 cstate->off_linkhdr.constant_part = 0;
1064 cstate->off_linkhdr.is_variable = 0;
1065 cstate->off_linkhdr.reg = -1;
1066
1067 /*
1068 * XXX
1069 */
1070 cstate->off_linkpl.constant_part = 0;
1071 cstate->off_linkpl.is_variable = 0;
1072 cstate->off_linkpl.reg = -1;
1073
1074 cstate->off_linktype.constant_part = 0;
1075 cstate->off_linktype.is_variable = 0;
1076 cstate->off_linktype.reg = -1;
1077
1078 /*
1079 * Assume it's not raw ATM with a pseudo-header, for now.
1080 */
1081 cstate->is_atm = 0;
1082 cstate->off_vpi = OFFSET_NOT_SET;
1083 cstate->off_vci = OFFSET_NOT_SET;
1084 cstate->off_proto = OFFSET_NOT_SET;
1085 cstate->off_payload = OFFSET_NOT_SET;
1086
1087 /*
1088 * And not Geneve.
1089 */
1090 cstate->is_geneve = 0;
1091
1092 /*
1093 * No variable length VLAN offset by default
1094 */
1095 cstate->is_vlan_vloffset = 0;
1096
1097 /*
1098 * And assume we're not doing SS7.
1099 */
1100 cstate->off_li = OFFSET_NOT_SET;
1101 cstate->off_li_hsl = OFFSET_NOT_SET;
1102 cstate->off_sio = OFFSET_NOT_SET;
1103 cstate->off_opc = OFFSET_NOT_SET;
1104 cstate->off_dpc = OFFSET_NOT_SET;
1105 cstate->off_sls = OFFSET_NOT_SET;
1106
1107 cstate->label_stack_depth = 0;
1108 cstate->vlan_stack_depth = 0;
1109
1110 switch (cstate->linktype) {
1111
1112 case DLT_ARCNET:
1113 cstate->off_linktype.constant_part = 2;
1114 cstate->off_linkpl.constant_part = 6;
1115 cstate->off_nl = 0; /* XXX in reality, variable! */
1116 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1117 break;
1118
1119 case DLT_ARCNET_LINUX:
1120 cstate->off_linktype.constant_part = 4;
1121 cstate->off_linkpl.constant_part = 8;
1122 cstate->off_nl = 0; /* XXX in reality, variable! */
1123 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1124 break;
1125
1126 case DLT_EN10MB:
1127 cstate->off_linktype.constant_part = 12;
1128 cstate->off_linkpl.constant_part = 14; /* Ethernet header length */
1129 cstate->off_nl = 0; /* Ethernet II */
1130 cstate->off_nl_nosnap = 3; /* 802.3+802.2 */
1131 break;
1132
1133 case DLT_SLIP:
1134 /*
1135 * SLIP doesn't have a link level type. The 16 byte
1136 * header is hacked into our SLIP driver.
1137 */
1138 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1139 cstate->off_linkpl.constant_part = 16;
1140 cstate->off_nl = 0;
1141 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1142 break;
1143
1144 case DLT_SLIP_BSDOS:
1145 /* XXX this may be the same as the DLT_PPP_BSDOS case */
1146 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1147 /* XXX end */
1148 cstate->off_linkpl.constant_part = 24;
1149 cstate->off_nl = 0;
1150 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1151 break;
1152
1153 case DLT_NULL:
1154 case DLT_LOOP:
1155 cstate->off_linktype.constant_part = 0;
1156 cstate->off_linkpl.constant_part = 4;
1157 cstate->off_nl = 0;
1158 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1159 break;
1160
1161 case DLT_ENC:
1162 cstate->off_linktype.constant_part = 0;
1163 cstate->off_linkpl.constant_part = 12;
1164 cstate->off_nl = 0;
1165 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1166 break;
1167
1168 case DLT_PPP:
1169 case DLT_PPP_PPPD:
1170 case DLT_C_HDLC: /* BSD/OS Cisco HDLC */
1171 case DLT_PPP_SERIAL: /* NetBSD sync/async serial PPP */
1172 cstate->off_linktype.constant_part = 2; /* skip HDLC-like framing */
1173 cstate->off_linkpl.constant_part = 4; /* skip HDLC-like framing and protocol field */
1174 cstate->off_nl = 0;
1175 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1176 break;
1177
1178 case DLT_PPP_ETHER:
1179 /*
1180 * This does no include the Ethernet header, and
1181 * only covers session state.
1182 */
1183 cstate->off_linktype.constant_part = 6;
1184 cstate->off_linkpl.constant_part = 8;
1185 cstate->off_nl = 0;
1186 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1187 break;
1188
1189 case DLT_PPP_BSDOS:
1190 cstate->off_linktype.constant_part = 5;
1191 cstate->off_linkpl.constant_part = 24;
1192 cstate->off_nl = 0;
1193 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1194 break;
1195
1196 case DLT_FDDI:
1197 /*
1198 * FDDI doesn't really have a link-level type field.
1199 * We set "off_linktype" to the 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?
1204 */
1205 cstate->off_linktype.constant_part = 13;
1206 cstate->off_linktype.constant_part += cstate->pcap_fddipad;
1207 cstate->off_linkpl.constant_part = 13; /* FDDI MAC header length */
1208 cstate->off_linkpl.constant_part += cstate->pcap_fddipad;
1209 cstate->off_nl = 8; /* 802.2+SNAP */
1210 cstate->off_nl_nosnap = 3; /* 802.2 */
1211 break;
1212
1213 case DLT_IEEE802:
1214 /*
1215 * Token Ring doesn't really have a link-level type field.
1216 * We set "off_linktype" to the offset of the LLC header.
1217 *
1218 * To check for Ethernet types, we assume that SSAP = SNAP
1219 * is being used and pick out the encapsulated Ethernet type.
1220 * XXX - should we generate code to check for SNAP?
1221 *
1222 * XXX - the header is actually variable-length.
1223 * Some various Linux patched versions gave 38
1224 * as "off_linktype" and 40 as "off_nl"; however,
1225 * if a token ring packet has *no* routing
1226 * information, i.e. is not source-routed, the correct
1227 * values are 20 and 22, as they are in the vanilla code.
1228 *
1229 * A packet is source-routed iff the uppermost bit
1230 * of the first byte of the source address, at an
1231 * offset of 8, has the uppermost bit set. If the
1232 * packet is source-routed, the total number of bytes
1233 * of routing information is 2 plus bits 0x1F00 of
1234 * the 16-bit value at an offset of 14 (shifted right
1235 * 8 - figure out which byte that is).
1236 */
1237 cstate->off_linktype.constant_part = 14;
1238 cstate->off_linkpl.constant_part = 14; /* Token Ring MAC header length */
1239 cstate->off_nl = 8; /* 802.2+SNAP */
1240 cstate->off_nl_nosnap = 3; /* 802.2 */
1241 break;
1242
1243 case DLT_PRISM_HEADER:
1244 case DLT_IEEE802_11_RADIO_AVS:
1245 case DLT_IEEE802_11_RADIO:
1246 cstate->off_linkhdr.is_variable = 1;
1247 /* Fall through, 802.11 doesn't have a variable link
1248 * prefix but is otherwise the same. */
1249
1250 case DLT_IEEE802_11:
1251 /*
1252 * 802.11 doesn't really have a link-level type field.
1253 * We set "off_linktype.constant_part" to the offset of
1254 * the LLC header.
1255 *
1256 * To check for Ethernet types, we assume that SSAP = SNAP
1257 * is being used and pick out the encapsulated Ethernet type.
1258 * XXX - should we generate code to check for SNAP?
1259 *
1260 * We also handle variable-length radio headers here.
1261 * The Prism header is in theory variable-length, but in
1262 * practice it's always 144 bytes long. However, some
1263 * drivers on Linux use ARPHRD_IEEE80211_PRISM, but
1264 * sometimes or always supply an AVS header, so we
1265 * have to check whether the radio header is a Prism
1266 * header or an AVS header, so, in practice, it's
1267 * variable-length.
1268 */
1269 cstate->off_linktype.constant_part = 24;
1270 cstate->off_linkpl.constant_part = 0; /* link-layer header is variable-length */
1271 cstate->off_linkpl.is_variable = 1;
1272 cstate->off_nl = 8; /* 802.2+SNAP */
1273 cstate->off_nl_nosnap = 3; /* 802.2 */
1274 break;
1275
1276 case DLT_PPI:
1277 /*
1278 * At the moment we treat PPI the same way that we treat
1279 * normal Radiotap encoded packets. The difference is in
1280 * the function that generates the code at the beginning
1281 * to compute the header length. Since this code generator
1282 * of PPI supports bare 802.11 encapsulation only (i.e.
1283 * the encapsulated DLT should be DLT_IEEE802_11) we
1284 * generate code to check for this too.
1285 */
1286 cstate->off_linktype.constant_part = 24;
1287 cstate->off_linkpl.constant_part = 0; /* link-layer header is variable-length */
1288 cstate->off_linkpl.is_variable = 1;
1289 cstate->off_linkhdr.is_variable = 1;
1290 cstate->off_nl = 8; /* 802.2+SNAP */
1291 cstate->off_nl_nosnap = 3; /* 802.2 */
1292 break;
1293
1294 case DLT_ATM_RFC1483:
1295 case DLT_ATM_CLIP: /* Linux ATM defines this */
1296 /*
1297 * assume routed, non-ISO PDUs
1298 * (i.e., LLC = 0xAA-AA-03, OUT = 0x00-00-00)
1299 *
1300 * XXX - what about ISO PDUs, e.g. CLNP, ISIS, ESIS,
1301 * or PPP with the PPP NLPID (e.g., PPPoA)? The
1302 * latter would presumably be treated the way PPPoE
1303 * should be, so you can do "pppoe and udp port 2049"
1304 * or "pppoa and tcp port 80" and have it check for
1305 * PPPo{A,E} and a PPP protocol of IP and....
1306 */
1307 cstate->off_linktype.constant_part = 0;
1308 cstate->off_linkpl.constant_part = 0; /* packet begins with LLC header */
1309 cstate->off_nl = 8; /* 802.2+SNAP */
1310 cstate->off_nl_nosnap = 3; /* 802.2 */
1311 break;
1312
1313 case DLT_SUNATM:
1314 /*
1315 * Full Frontal ATM; you get AALn PDUs with an ATM
1316 * pseudo-header.
1317 */
1318 cstate->is_atm = 1;
1319 cstate->off_vpi = SUNATM_VPI_POS;
1320 cstate->off_vci = SUNATM_VCI_POS;
1321 cstate->off_proto = PROTO_POS;
1322 cstate->off_payload = SUNATM_PKT_BEGIN_POS;
1323 cstate->off_linktype.constant_part = cstate->off_payload;
1324 cstate->off_linkpl.constant_part = cstate->off_payload; /* if LLC-encapsulated */
1325 cstate->off_nl = 8; /* 802.2+SNAP */
1326 cstate->off_nl_nosnap = 3; /* 802.2 */
1327 break;
1328
1329 case DLT_RAW:
1330 case DLT_IPV4:
1331 case DLT_IPV6:
1332 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1333 cstate->off_linkpl.constant_part = 0;
1334 cstate->off_nl = 0;
1335 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1336 break;
1337
1338 case DLT_LINUX_SLL: /* fake header for Linux cooked socket */
1339 cstate->off_linktype.constant_part = 14;
1340 cstate->off_linkpl.constant_part = 16;
1341 cstate->off_nl = 0;
1342 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1343 break;
1344
1345 case DLT_LTALK:
1346 /*
1347 * LocalTalk does have a 1-byte type field in the LLAP header,
1348 * but really it just indicates whether there is a "short" or
1349 * "long" DDP packet following.
1350 */
1351 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1352 cstate->off_linkpl.constant_part = 0;
1353 cstate->off_nl = 0;
1354 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1355 break;
1356
1357 case DLT_IP_OVER_FC:
1358 /*
1359 * RFC 2625 IP-over-Fibre-Channel doesn't really have a
1360 * link-level type field. We set "off_linktype" to the
1361 * offset of the LLC header.
1362 *
1363 * To check for Ethernet types, we assume that SSAP = SNAP
1364 * is being used and pick out the encapsulated Ethernet type.
1365 * XXX - should we generate code to check for SNAP? RFC
1366 * 2625 says SNAP should be used.
1367 */
1368 cstate->off_linktype.constant_part = 16;
1369 cstate->off_linkpl.constant_part = 16;
1370 cstate->off_nl = 8; /* 802.2+SNAP */
1371 cstate->off_nl_nosnap = 3; /* 802.2 */
1372 break;
1373
1374 case DLT_FRELAY:
1375 /*
1376 * XXX - we should set this to handle SNAP-encapsulated
1377 * frames (NLPID of 0x80).
1378 */
1379 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1380 cstate->off_linkpl.constant_part = 0;
1381 cstate->off_nl = 0;
1382 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1383 break;
1384
1385 /*
1386 * the only BPF-interesting FRF.16 frames are non-control frames;
1387 * Frame Relay has a variable length link-layer
1388 * so lets start with offset 4 for now and increments later on (FIXME);
1389 */
1390 case DLT_MFR:
1391 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1392 cstate->off_linkpl.constant_part = 0;
1393 cstate->off_nl = 4;
1394 cstate->off_nl_nosnap = 0; /* XXX - for now -> no 802.2 LLC */
1395 break;
1396
1397 case DLT_APPLE_IP_OVER_IEEE1394:
1398 cstate->off_linktype.constant_part = 16;
1399 cstate->off_linkpl.constant_part = 18;
1400 cstate->off_nl = 0;
1401 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1402 break;
1403
1404 case DLT_SYMANTEC_FIREWALL:
1405 cstate->off_linktype.constant_part = 6;
1406 cstate->off_linkpl.constant_part = 44;
1407 cstate->off_nl = 0; /* Ethernet II */
1408 cstate->off_nl_nosnap = 0; /* XXX - what does it do with 802.3 packets? */
1409 break;
1410
1411#ifdef HAVE_NET_PFVAR_H
1412 case DLT_PFLOG:
1413 cstate->off_linktype.constant_part = 0;
1414 cstate->off_linkpl.constant_part = PFLOG_HDRLEN;
1415 cstate->off_nl = 0;
1416 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1417 break;
1418#endif
1419
1420 case DLT_JUNIPER_MFR:
1421 case DLT_JUNIPER_MLFR:
1422 case DLT_JUNIPER_MLPPP:
1423 case DLT_JUNIPER_PPP:
1424 case DLT_JUNIPER_CHDLC:
1425 case DLT_JUNIPER_FRELAY:
1426 cstate->off_linktype.constant_part = 4;
1427 cstate->off_linkpl.constant_part = 4;
1428 cstate->off_nl = 0;
1429 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1430 break;
1431
1432 case DLT_JUNIPER_ATM1:
1433 cstate->off_linktype.constant_part = 4; /* in reality variable between 4-8 */
1434 cstate->off_linkpl.constant_part = 4; /* in reality variable between 4-8 */
1435 cstate->off_nl = 0;
1436 cstate->off_nl_nosnap = 10;
1437 break;
1438
1439 case DLT_JUNIPER_ATM2:
1440 cstate->off_linktype.constant_part = 8; /* in reality variable between 8-12 */
1441 cstate->off_linkpl.constant_part = 8; /* in reality variable between 8-12 */
1442 cstate->off_nl = 0;
1443 cstate->off_nl_nosnap = 10;
1444 break;
1445
1446 /* frames captured on a Juniper PPPoE service PIC
1447 * contain raw ethernet frames */
1448 case DLT_JUNIPER_PPPOE:
1449 case DLT_JUNIPER_ETHER:
1450 cstate->off_linkpl.constant_part = 14;
1451 cstate->off_linktype.constant_part = 16;
1452 cstate->off_nl = 18; /* Ethernet II */
1453 cstate->off_nl_nosnap = 21; /* 802.3+802.2 */
1454 break;
1455
1456 case DLT_JUNIPER_PPPOE_ATM:
1457 cstate->off_linktype.constant_part = 4;
1458 cstate->off_linkpl.constant_part = 6;
1459 cstate->off_nl = 0;
1460 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1461 break;
1462
1463 case DLT_JUNIPER_GGSN:
1464 cstate->off_linktype.constant_part = 6;
1465 cstate->off_linkpl.constant_part = 12;
1466 cstate->off_nl = 0;
1467 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1468 break;
1469
1470 case DLT_JUNIPER_ES:
1471 cstate->off_linktype.constant_part = 6;
1472 cstate->off_linkpl.constant_part = OFFSET_NOT_SET; /* not really a network layer but raw IP addresses */
1473 cstate->off_nl = OFFSET_NOT_SET; /* not really a network layer but raw IP addresses */
1474 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1475 break;
1476
1477 case DLT_JUNIPER_MONITOR:
1478 cstate->off_linktype.constant_part = 12;
1479 cstate->off_linkpl.constant_part = 12;
1480 cstate->off_nl = 0; /* raw IP/IP6 header */
1481 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1482 break;
1483
1484 case DLT_BACNET_MS_TP:
1485 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1486 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1487 cstate->off_nl = OFFSET_NOT_SET;
1488 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1489 break;
1490
1491 case DLT_JUNIPER_SERVICES:
1492 cstate->off_linktype.constant_part = 12;
1493 cstate->off_linkpl.constant_part = OFFSET_NOT_SET; /* L3 proto location dep. on cookie type */
1494 cstate->off_nl = OFFSET_NOT_SET; /* L3 proto location dep. on cookie type */
1495 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1496 break;
1497
1498 case DLT_JUNIPER_VP:
1499 cstate->off_linktype.constant_part = 18;
1500 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1501 cstate->off_nl = OFFSET_NOT_SET;
1502 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1503 break;
1504
1505 case DLT_JUNIPER_ST:
1506 cstate->off_linktype.constant_part = 18;
1507 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1508 cstate->off_nl = OFFSET_NOT_SET;
1509 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1510 break;
1511
1512 case DLT_JUNIPER_ISM:
1513 cstate->off_linktype.constant_part = 8;
1514 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1515 cstate->off_nl = OFFSET_NOT_SET;
1516 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1517 break;
1518
1519 case DLT_JUNIPER_VS:
1520 case DLT_JUNIPER_SRX_E2E:
1521 case DLT_JUNIPER_FIBRECHANNEL:
1522 case DLT_JUNIPER_ATM_CEMIC:
1523 cstate->off_linktype.constant_part = 8;
1524 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1525 cstate->off_nl = OFFSET_NOT_SET;
1526 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1527 break;
1528
1529 case DLT_MTP2:
1530 cstate->off_li = 2;
1531 cstate->off_li_hsl = 4;
1532 cstate->off_sio = 3;
1533 cstate->off_opc = 4;
1534 cstate->off_dpc = 4;
1535 cstate->off_sls = 7;
1536 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1537 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1538 cstate->off_nl = OFFSET_NOT_SET;
1539 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1540 break;
1541
1542 case DLT_MTP2_WITH_PHDR:
1543 cstate->off_li = 6;
1544 cstate->off_li_hsl = 8;
1545 cstate->off_sio = 7;
1546 cstate->off_opc = 8;
1547 cstate->off_dpc = 8;
1548 cstate->off_sls = 11;
1549 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1550 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1551 cstate->off_nl = OFFSET_NOT_SET;
1552 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1553 break;
1554
1555 case DLT_ERF:
1556 cstate->off_li = 22;
1557 cstate->off_li_hsl = 24;
1558 cstate->off_sio = 23;
1559 cstate->off_opc = 24;
1560 cstate->off_dpc = 24;
1561 cstate->off_sls = 27;
1562 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1563 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1564 cstate->off_nl = OFFSET_NOT_SET;
1565 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1566 break;
1567
1568 case DLT_PFSYNC:
1569 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1570 cstate->off_linkpl.constant_part = 4;
1571 cstate->off_nl = 0;
1572 cstate->off_nl_nosnap = 0;
1573 break;
1574
1575 case DLT_AX25_KISS:
1576 /*
1577 * Currently, only raw "link[N:M]" filtering is supported.
1578 */
1579 cstate->off_linktype.constant_part = OFFSET_NOT_SET; /* variable, min 15, max 71 steps of 7 */
1580 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1581 cstate->off_nl = OFFSET_NOT_SET; /* variable, min 16, max 71 steps of 7 */
1582 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1583 break;
1584
1585 case DLT_IPNET:
1586 cstate->off_linktype.constant_part = 1;
1587 cstate->off_linkpl.constant_part = 24; /* ipnet header length */
1588 cstate->off_nl = 0;
1589 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1590 break;
1591
1592 case DLT_NETANALYZER:
1593 cstate->off_linkhdr.constant_part = 4; /* Ethernet header is past 4-byte pseudo-header */
1594 cstate->off_linktype.constant_part = cstate->off_linkhdr.constant_part + 12;
1595 cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 14; /* pseudo-header+Ethernet header length */
1596 cstate->off_nl = 0; /* Ethernet II */
1597 cstate->off_nl_nosnap = 3; /* 802.3+802.2 */
1598 break;
1599
1600 case DLT_NETANALYZER_TRANSPARENT:
1601 cstate->off_linkhdr.constant_part = 12; /* MAC header is past 4-byte pseudo-header, preamble, and SFD */
1602 cstate->off_linktype.constant_part = cstate->off_linkhdr.constant_part + 12;
1603 cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 14; /* pseudo-header+preamble+SFD+Ethernet header length */
1604 cstate->off_nl = 0; /* Ethernet II */
1605 cstate->off_nl_nosnap = 3; /* 802.3+802.2 */
1606 break;
1607
1608 default:
1609 /*
1610 * For values in the range in which we've assigned new
1611 * DLT_ values, only raw "link[N:M]" filtering is supported.
1612 */
1613 if (cstate->linktype >= DLT_MATCHING_MIN &&
1614 cstate->linktype <= DLT_MATCHING_MAX) {
1615 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1616 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1617 cstate->off_nl = OFFSET_NOT_SET;
1618 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1619 } else {
1620 bpf_error(cstate, "unknown data link type %d", cstate->linktype);
1621 }
1622 break;
1623 }
1624
1625 cstate->off_outermostlinkhdr = cstate->off_prevlinkhdr = cstate->off_linkhdr;
1626}
1627
1628/*
1629 * Load a value relative to the specified absolute offset.
1630 */
1631static struct slist *
1632gen_load_absoffsetrel(compiler_state_t *cstate, bpf_abs_offset *abs_offset,
1633 u_int offset, u_int size)
1634{
1635 struct slist *s, *s2;
1636
1637 s = gen_abs_offset_varpart(cstate, abs_offset);
1638
1639 /*
1640 * If "s" is non-null, it has code to arrange that the X register
1641 * contains the variable part of the absolute offset, so we
1642 * generate a load relative to that, with an offset of
1643 * abs_offset->constant_part + offset.
1644 *
1645 * Otherwise, we can do an absolute load with an offset of
1646 * abs_offset->constant_part + offset.
1647 */
1648 if (s != NULL) {
1649 /*
1650 * "s" points to a list of statements that puts the
1651 * variable part of the absolute offset into the X register.
1652 * Do an indirect load, to use the X register as an offset.
1653 */
1654 s2 = new_stmt(cstate, BPF_LD|BPF_IND|size);
1655 s2->s.k = abs_offset->constant_part + offset;
1656 sappend(s, s2);
1657 } else {
1658 /*
1659 * There is no variable part of the absolute offset, so
1660 * just do an absolute load.
1661 */
1662 s = new_stmt(cstate, BPF_LD|BPF_ABS|size);
1663 s->s.k = abs_offset->constant_part + offset;
1664 }
1665 return s;
1666}
1667
1668/*
1669 * Load a value relative to the beginning of the specified header.
1670 */
1671static struct slist *
1672gen_load_a(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
1673 u_int size)
1674{
1675 struct slist *s, *s2;
1676
1677 switch (offrel) {
1678
1679 case OR_PACKET:
1680 s = new_stmt(cstate, BPF_LD|BPF_ABS|size);
1681 s->s.k = offset;
1682 break;
1683
1684 case OR_LINKHDR:
1685 s = gen_load_absoffsetrel(cstate, &cstate->off_linkhdr, offset, size);
1686 break;
1687
1688 case OR_PREVLINKHDR:
1689 s = gen_load_absoffsetrel(cstate, &cstate->off_prevlinkhdr, offset, size);
1690 break;
1691
1692 case OR_LLC:
1693 s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, offset, size);
1694 break;
1695
1696 case OR_PREVMPLSHDR:
1697 s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl - 4 + offset, size);
1698 break;
1699
1700 case OR_LINKPL:
1701 s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl + offset, size);
1702 break;
1703
1704 case OR_LINKPL_NOSNAP:
1705 s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl_nosnap + offset, size);
1706 break;
1707
1708 case OR_LINKTYPE:
1709 s = gen_load_absoffsetrel(cstate, &cstate->off_linktype, offset, size);
1710 break;
1711
1712 case OR_TRAN_IPV4:
1713 /*
1714 * Load the X register with the length of the IPv4 header
1715 * (plus the offset of the link-layer header, if it's
1716 * preceded by a variable-length header such as a radio
1717 * header), in bytes.
1718 */
1719 s = gen_loadx_iphdrlen(cstate);
1720
1721 /*
1722 * Load the item at {offset of the link-layer payload} +
1723 * {offset, relative to the start of the link-layer
1724 * paylod, of the IPv4 header} + {length of the IPv4 header} +
1725 * {specified offset}.
1726 *
1727 * If the offset of the link-layer payload is variable,
1728 * the variable part of that offset is included in the
1729 * value in the X register, and we include the constant
1730 * part in the offset of the load.
1731 */
1732 s2 = new_stmt(cstate, BPF_LD|BPF_IND|size);
1733 s2->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + offset;
1734 sappend(s, s2);
1735 break;
1736
1737 case OR_TRAN_IPV6:
1738 s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl + 40 + offset, size);
1739 break;
1740
1741 default:
1742 abort();
1743 /* NOTREACHED */
1744 }
1745 return s;
1746}
1747
1748/*
1749 * Generate code to load into the X register the sum of the length of
1750 * the IPv4 header and the variable part of the offset of the link-layer
1751 * payload.
1752 */
1753static struct slist *
1754gen_loadx_iphdrlen(compiler_state_t *cstate)
1755{
1756 struct slist *s, *s2;
1757
1758 s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl);
1759 if (s != NULL) {
1760 /*
1761 * The offset of the link-layer payload has a variable
1762 * part. "s" points to a list of statements that put
1763 * the variable part of that offset into the X register.
1764 *
1765 * The 4*([k]&0xf) addressing mode can't be used, as we
1766 * don't have a constant offset, so we have to load the
1767 * value in question into the A register and add to it
1768 * the value from the X register.
1769 */
1770 s2 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
1771 s2->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
1772 sappend(s, s2);
1773 s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
1774 s2->s.k = 0xf;
1775 sappend(s, s2);
1776 s2 = new_stmt(cstate, BPF_ALU|BPF_LSH|BPF_K);
1777 s2->s.k = 2;
1778 sappend(s, s2);
1779
1780 /*
1781 * The A register now contains the length of the IP header.
1782 * We need to add to it the variable part of the offset of
1783 * the link-layer payload, which is still in the X
1784 * register, and move the result into the X register.
1785 */
1786 sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
1787 sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
1788 } else {
1789 /*
1790 * The offset of the link-layer payload is a constant,
1791 * so no code was generated to load the (non-existent)
1792 * variable part of that offset.
1793 *
1794 * This means we can use the 4*([k]&0xf) addressing
1795 * mode. Load the length of the IPv4 header, which
1796 * is at an offset of cstate->off_nl from the beginning of
1797 * the link-layer payload, and thus at an offset of
1798 * cstate->off_linkpl.constant_part + cstate->off_nl from the beginning
1799 * of the raw packet data, using that addressing mode.
1800 */
1801 s = new_stmt(cstate, BPF_LDX|BPF_MSH|BPF_B);
1802 s->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
1803 }
1804 return s;
1805}
1806
1807
1808static struct block *
1809gen_uncond(compiler_state_t *cstate, int rsense)
1810{
1811 struct block *b;
1812 struct slist *s;
1813
1814 s = new_stmt(cstate, BPF_LD|BPF_IMM);
1815 s->s.k = !rsense;
1816 b = new_block(cstate, JMP(BPF_JEQ));
1817 b->stmts = s;
1818
1819 return b;
1820}
1821
1822static inline struct block *
1823gen_true(compiler_state_t *cstate)
1824{
1825 return gen_uncond(cstate, 1);
1826}
1827
1828static inline struct block *
1829gen_false(compiler_state_t *cstate)
1830{
1831 return gen_uncond(cstate, 0);
1832}
1833
1834/*
1835 * Byte-swap a 32-bit number.
1836 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
1837 * big-endian platforms.)
1838 */
1839#define SWAPLONG(y) \
1840((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
1841
1842/*
1843 * Generate code to match a particular packet type.
1844 *
1845 * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
1846 * value, if <= ETHERMTU. We use that to determine whether to
1847 * match the type/length field or to check the type/length field for
1848 * a value <= ETHERMTU to see whether it's a type field and then do
1849 * the appropriate test.
1850 */
1851static struct block *
1852gen_ether_linktype(compiler_state_t *cstate, int proto)
1853{
1854 struct block *b0, *b1;
1855
1856 switch (proto) {
1857
1858 case LLCSAP_ISONS:
1859 case LLCSAP_IP:
1860 case LLCSAP_NETBEUI:
1861 /*
1862 * OSI protocols and NetBEUI always use 802.2 encapsulation,
1863 * so we check the DSAP and SSAP.
1864 *
1865 * LLCSAP_IP checks for IP-over-802.2, rather
1866 * than IP-over-Ethernet or IP-over-SNAP.
1867 *
1868 * XXX - should we check both the DSAP and the
1869 * SSAP, like this, or should we check just the
1870 * DSAP, as we do for other types <= ETHERMTU
1871 * (i.e., other SAP values)?
1872 */
1873 b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
1874 gen_not(b0);
1875 b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_int32)
1876 ((proto << 8) | proto));
1877 gen_and(b0, b1);
1878 return b1;
1879
1880 case LLCSAP_IPX:
1881 /*
1882 * Check for;
1883 *
1884 * Ethernet_II frames, which are Ethernet
1885 * frames with a frame type of ETHERTYPE_IPX;
1886 *
1887 * Ethernet_802.3 frames, which are 802.3
1888 * frames (i.e., the type/length field is
1889 * a length field, <= ETHERMTU, rather than
1890 * a type field) with the first two bytes
1891 * after the Ethernet/802.3 header being
1892 * 0xFFFF;
1893 *
1894 * Ethernet_802.2 frames, which are 802.3
1895 * frames with an 802.2 LLC header and
1896 * with the IPX LSAP as the DSAP in the LLC
1897 * header;
1898 *
1899 * Ethernet_SNAP frames, which are 802.3
1900 * frames with an LLC header and a SNAP
1901 * header and with an OUI of 0x000000
1902 * (encapsulated Ethernet) and a protocol
1903 * ID of ETHERTYPE_IPX in the SNAP header.
1904 *
1905 * XXX - should we generate the same code both
1906 * for tests for LLCSAP_IPX and for ETHERTYPE_IPX?
1907 */
1908
1909 /*
1910 * This generates code to check both for the
1911 * IPX LSAP (Ethernet_802.2) and for Ethernet_802.3.
1912 */
1913 b0 = gen_cmp(cstate, OR_LLC, 0, BPF_B, (bpf_int32)LLCSAP_IPX);
1914 b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_int32)0xFFFF);
1915 gen_or(b0, b1);
1916
1917 /*
1918 * Now we add code to check for SNAP frames with
1919 * ETHERTYPE_IPX, i.e. Ethernet_SNAP.
1920 */
1921 b0 = gen_snap(cstate, 0x000000, ETHERTYPE_IPX);
1922 gen_or(b0, b1);
1923
1924 /*
1925 * Now we generate code to check for 802.3
1926 * frames in general.
1927 */
1928 b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
1929 gen_not(b0);
1930
1931 /*
1932 * Now add the check for 802.3 frames before the
1933 * check for Ethernet_802.2 and Ethernet_802.3,
1934 * as those checks should only be done on 802.3
1935 * frames, not on Ethernet frames.
1936 */
1937 gen_and(b0, b1);
1938
1939 /*
1940 * Now add the check for Ethernet_II frames, and
1941 * do that before checking for the other frame
1942 * types.
1943 */
1944 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)ETHERTYPE_IPX);
1945 gen_or(b0, b1);
1946 return b1;
1947
1948 case ETHERTYPE_ATALK:
1949 case ETHERTYPE_AARP:
1950 /*
1951 * EtherTalk (AppleTalk protocols on Ethernet link
1952 * layer) may use 802.2 encapsulation.
1953 */
1954
1955 /*
1956 * Check for 802.2 encapsulation (EtherTalk phase 2?);
1957 * we check for an Ethernet type field less than
1958 * 1500, which means it's an 802.3 length field.
1959 */
1960 b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
1961 gen_not(b0);
1962
1963 /*
1964 * 802.2-encapsulated ETHERTYPE_ATALK packets are
1965 * SNAP packets with an organization code of
1966 * 0x080007 (Apple, for Appletalk) and a protocol
1967 * type of ETHERTYPE_ATALK (Appletalk).
1968 *
1969 * 802.2-encapsulated ETHERTYPE_AARP packets are
1970 * SNAP packets with an organization code of
1971 * 0x000000 (encapsulated Ethernet) and a protocol
1972 * type of ETHERTYPE_AARP (Appletalk ARP).
1973 */
1974 if (proto == ETHERTYPE_ATALK)
1975 b1 = gen_snap(cstate, 0x080007, ETHERTYPE_ATALK);
1976 else /* proto == ETHERTYPE_AARP */
1977 b1 = gen_snap(cstate, 0x000000, ETHERTYPE_AARP);
1978 gen_and(b0, b1);
1979
1980 /*
1981 * Check for Ethernet encapsulation (Ethertalk
1982 * phase 1?); we just check for the Ethernet
1983 * protocol type.
1984 */
1985 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
1986
1987 gen_or(b0, b1);
1988 return b1;
1989
1990 default:
1991 if (proto <= ETHERMTU) {
1992 /*
1993 * This is an LLC SAP value, so the frames
1994 * that match would be 802.2 frames.
1995 * Check that the frame is an 802.2 frame
1996 * (i.e., that the length/type field is
1997 * a length field, <= ETHERMTU) and
1998 * then check the DSAP.
1999 */
2000 b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
2001 gen_not(b0);
2002 b1 = gen_cmp(cstate, OR_LINKTYPE, 2, BPF_B, (bpf_int32)proto);
2003 gen_and(b0, b1);
2004 return b1;
2005 } else {
2006 /*
2007 * This is an Ethernet type, so compare
2008 * the length/type field with it (if
2009 * the frame is an 802.2 frame, the length
2010 * field will be <= ETHERMTU, and, as
2011 * "proto" is > ETHERMTU, this test
2012 * will fail and the frame won't match,
2013 * which is what we want).
2014 */
2015 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H,
2016 (bpf_int32)proto);
2017 }
2018 }
2019}
2020
2021static struct block *
2022gen_loopback_linktype(compiler_state_t *cstate, int proto)
2023{
2024 /*
2025 * For DLT_NULL, the link-layer header is a 32-bit word
2026 * containing an AF_ value in *host* byte order, and for
2027 * DLT_ENC, the link-layer header begins with a 32-bit
2028 * word containing an AF_ value in host byte order.
2029 *
2030 * In addition, if we're reading a saved capture file,
2031 * the host byte order in the capture may not be the
2032 * same as the host byte order on this machine.
2033 *
2034 * For DLT_LOOP, the link-layer header is a 32-bit
2035 * word containing an AF_ value in *network* byte order.
2036 */
2037 if (cstate->linktype == DLT_NULL || cstate->linktype == DLT_ENC) {
2038 /*
2039 * The AF_ value is in host byte order, but the BPF
2040 * interpreter will convert it to network byte order.
2041 *
2042 * If this is a save file, and it's from a machine
2043 * with the opposite byte order to ours, we byte-swap
2044 * the AF_ value.
2045 *
2046 * Then we run it through "htonl()", and generate
2047 * code to compare against the result.
2048 */
2049 if (cstate->bpf_pcap->rfile != NULL && cstate->bpf_pcap->swapped)
2050 proto = SWAPLONG(proto);
2051 proto = htonl(proto);
2052 }
2053 return (gen_cmp(cstate, OR_LINKHDR, 0, BPF_W, (bpf_int32)proto));
2054}
2055
2056/*
2057 * "proto" is an Ethernet type value and for IPNET, if it is not IPv4
2058 * or IPv6 then we have an error.
2059 */
2060static struct block *
2061gen_ipnet_linktype(compiler_state_t *cstate, int proto)
2062{
2063 switch (proto) {
2064
2065 case ETHERTYPE_IP:
2066 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B, (bpf_int32)IPH_AF_INET);
2067 /* NOTREACHED */
2068
2069 case ETHERTYPE_IPV6:
2070 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
2071 (bpf_int32)IPH_AF_INET6);
2072 /* NOTREACHED */
2073
2074 default:
2075 break;
2076 }
2077
2078 return gen_false(cstate);
2079}
2080
2081/*
2082 * Generate code to match a particular packet type.
2083 *
2084 * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
2085 * value, if <= ETHERMTU. We use that to determine whether to
2086 * match the type field or to check the type field for the special
2087 * LINUX_SLL_P_802_2 value and then do the appropriate test.
2088 */
2089static struct block *
2090gen_linux_sll_linktype(compiler_state_t *cstate, int proto)
2091{
2092 struct block *b0, *b1;
2093
2094 switch (proto) {
2095
2096 case LLCSAP_ISONS:
2097 case LLCSAP_IP:
2098 case LLCSAP_NETBEUI:
2099 /*
2100 * OSI protocols and NetBEUI always use 802.2 encapsulation,
2101 * so we check the DSAP and SSAP.
2102 *
2103 * LLCSAP_IP checks for IP-over-802.2, rather
2104 * than IP-over-Ethernet or IP-over-SNAP.
2105 *
2106 * XXX - should we check both the DSAP and the
2107 * SSAP, like this, or should we check just the
2108 * DSAP, as we do for other types <= ETHERMTU
2109 * (i.e., other SAP values)?
2110 */
2111 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2);
2112 b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_int32)
2113 ((proto << 8) | proto));
2114 gen_and(b0, b1);
2115 return b1;
2116
2117 case LLCSAP_IPX:
2118 /*
2119 * Ethernet_II frames, which are Ethernet
2120 * frames with a frame type of ETHERTYPE_IPX;
2121 *
2122 * Ethernet_802.3 frames, which have a frame
2123 * type of LINUX_SLL_P_802_3;
2124 *
2125 * Ethernet_802.2 frames, which are 802.3
2126 * frames with an 802.2 LLC header (i.e, have
2127 * a frame type of LINUX_SLL_P_802_2) and
2128 * with the IPX LSAP as the DSAP in the LLC
2129 * header;
2130 *
2131 * Ethernet_SNAP frames, which are 802.3
2132 * frames with an LLC header and a SNAP
2133 * header and with an OUI of 0x000000
2134 * (encapsulated Ethernet) and a protocol
2135 * ID of ETHERTYPE_IPX in the SNAP header.
2136 *
2137 * First, do the checks on LINUX_SLL_P_802_2
2138 * frames; generate the check for either
2139 * Ethernet_802.2 or Ethernet_SNAP frames, and
2140 * then put a check for LINUX_SLL_P_802_2 frames
2141 * before it.
2142 */
2143 b0 = gen_cmp(cstate, OR_LLC, 0, BPF_B, (bpf_int32)LLCSAP_IPX);
2144 b1 = gen_snap(cstate, 0x000000, ETHERTYPE_IPX);
2145 gen_or(b0, b1);
2146 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2);
2147 gen_and(b0, b1);
2148
2149 /*
2150 * Now check for 802.3 frames and OR that with
2151 * the previous test.
2152 */
2153 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_3);
2154 gen_or(b0, b1);
2155
2156 /*
2157 * Now add the check for Ethernet_II frames, and
2158 * do that before checking for the other frame
2159 * types.
2160 */
2161 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)ETHERTYPE_IPX);
2162 gen_or(b0, b1);
2163 return b1;
2164
2165 case ETHERTYPE_ATALK:
2166 case ETHERTYPE_AARP:
2167 /*
2168 * EtherTalk (AppleTalk protocols on Ethernet link
2169 * layer) may use 802.2 encapsulation.
2170 */
2171
2172 /*
2173 * Check for 802.2 encapsulation (EtherTalk phase 2?);
2174 * we check for the 802.2 protocol type in the
2175 * "Ethernet type" field.
2176 */
2177 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2);
2178
2179 /*
2180 * 802.2-encapsulated ETHERTYPE_ATALK packets are
2181 * SNAP packets with an organization code of
2182 * 0x080007 (Apple, for Appletalk) and a protocol
2183 * type of ETHERTYPE_ATALK (Appletalk).
2184 *
2185 * 802.2-encapsulated ETHERTYPE_AARP packets are
2186 * SNAP packets with an organization code of
2187 * 0x000000 (encapsulated Ethernet) and a protocol
2188 * type of ETHERTYPE_AARP (Appletalk ARP).
2189 */
2190 if (proto == ETHERTYPE_ATALK)
2191 b1 = gen_snap(cstate, 0x080007, ETHERTYPE_ATALK);
2192 else /* proto == ETHERTYPE_AARP */
2193 b1 = gen_snap(cstate, 0x000000, ETHERTYPE_AARP);
2194 gen_and(b0, b1);
2195
2196 /*
2197 * Check for Ethernet encapsulation (Ethertalk
2198 * phase 1?); we just check for the Ethernet
2199 * protocol type.
2200 */
2201 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
2202
2203 gen_or(b0, b1);
2204 return b1;
2205
2206 default:
2207 if (proto <= ETHERMTU) {
2208 /*
2209 * This is an LLC SAP value, so the frames
2210 * that match would be 802.2 frames.
2211 * Check for the 802.2 protocol type
2212 * in the "Ethernet type" field, and
2213 * then check the DSAP.
2214 */
2215 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2);
2216 b1 = gen_cmp(cstate, OR_LINKHDR, cstate->off_linkpl.constant_part, BPF_B,
2217 (bpf_int32)proto);
2218 gen_and(b0, b1);
2219 return b1;
2220 } else {
2221 /*
2222 * This is an Ethernet type, so compare
2223 * the length/type field with it (if
2224 * the frame is an 802.2 frame, the length
2225 * field will be <= ETHERMTU, and, as
2226 * "proto" is > ETHERMTU, this test
2227 * will fail and the frame won't match,
2228 * which is what we want).
2229 */
2230 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
2231 }
2232 }
2233}
2234
2235static struct slist *
2236gen_load_prism_llprefixlen(compiler_state_t *cstate)
2237{
2238 struct slist *s1, *s2;
2239 struct slist *sjeq_avs_cookie;
2240 struct slist *sjcommon;
2241
2242 /*
2243 * This code is not compatible with the optimizer, as
2244 * we are generating jmp instructions within a normal
2245 * slist of instructions
2246 */
2247 cstate->no_optimize = 1;
2248
2249 /*
2250 * Generate code to load the length of the radio header into
2251 * the register assigned to hold that length, if one has been
2252 * assigned. (If one hasn't been assigned, no code we've
2253 * generated uses that prefix, so we don't need to generate any
2254 * code to load it.)
2255 *
2256 * Some Linux drivers use ARPHRD_IEEE80211_PRISM but sometimes
2257 * or always use the AVS header rather than the Prism header.
2258 * We load a 4-byte big-endian value at the beginning of the
2259 * raw packet data, and see whether, when masked with 0xFFFFF000,
2260 * it's equal to 0x80211000. If so, that indicates that it's
2261 * an AVS header (the masked-out bits are the version number).
2262 * Otherwise, it's a Prism header.
2263 *
2264 * XXX - the Prism header is also, in theory, variable-length,
2265 * but no known software generates headers that aren't 144
2266 * bytes long.
2267 */
2268 if (cstate->off_linkhdr.reg != -1) {
2269 /*
2270 * Load the cookie.
2271 */
2272 s1 = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
2273 s1->s.k = 0;
2274
2275 /*
2276 * AND it with 0xFFFFF000.
2277 */
2278 s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
2279 s2->s.k = 0xFFFFF000;
2280 sappend(s1, s2);
2281
2282 /*
2283 * Compare with 0x80211000.
2284 */
2285 sjeq_avs_cookie = new_stmt(cstate, JMP(BPF_JEQ));
2286 sjeq_avs_cookie->s.k = 0x80211000;
2287 sappend(s1, sjeq_avs_cookie);
2288
2289 /*
2290 * If it's AVS:
2291 *
2292 * The 4 bytes at an offset of 4 from the beginning of
2293 * the AVS header are the length of the AVS header.
2294 * That field is big-endian.
2295 */
2296 s2 = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
2297 s2->s.k = 4;
2298 sappend(s1, s2);
2299 sjeq_avs_cookie->s.jt = s2;
2300
2301 /*
2302 * Now jump to the code to allocate a register
2303 * into which to save the header length and
2304 * store the length there. (The "jump always"
2305 * instruction needs to have the k field set;
2306 * it's added to the PC, so, as we're jumping
2307 * over a single instruction, it should be 1.)
2308 */
2309 sjcommon = new_stmt(cstate, JMP(BPF_JA));
2310 sjcommon->s.k = 1;
2311 sappend(s1, sjcommon);
2312
2313 /*
2314 * Now for the code that handles the Prism header.
2315 * Just load the length of the Prism header (144)
2316 * into the A register. Have the test for an AVS
2317 * header branch here if we don't have an AVS header.
2318 */
2319 s2 = new_stmt(cstate, BPF_LD|BPF_W|BPF_IMM);
2320 s2->s.k = 144;
2321 sappend(s1, s2);
2322 sjeq_avs_cookie->s.jf = s2;
2323
2324 /*
2325 * Now allocate a register to hold that value and store
2326 * it. The code for the AVS header will jump here after
2327 * loading the length of the AVS header.
2328 */
2329 s2 = new_stmt(cstate, BPF_ST);
2330 s2->s.k = cstate->off_linkhdr.reg;
2331 sappend(s1, s2);
2332 sjcommon->s.jf = s2;
2333
2334 /*
2335 * Now move it into the X register.
2336 */
2337 s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2338 sappend(s1, s2);
2339
2340 return (s1);
2341 } else
2342 return (NULL);
2343}
2344
2345static struct slist *
2346gen_load_avs_llprefixlen(compiler_state_t *cstate)
2347{
2348 struct slist *s1, *s2;
2349
2350 /*
2351 * Generate code to load the length of the AVS header into
2352 * the register assigned to hold that length, if one has been
2353 * assigned. (If one hasn't been assigned, no code we've
2354 * generated uses that prefix, so we don't need to generate any
2355 * code to load it.)
2356 */
2357 if (cstate->off_linkhdr.reg != -1) {
2358 /*
2359 * The 4 bytes at an offset of 4 from the beginning of
2360 * the AVS header are the length of the AVS header.
2361 * That field is big-endian.
2362 */
2363 s1 = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
2364 s1->s.k = 4;
2365
2366 /*
2367 * Now allocate a register to hold that value and store
2368 * it.
2369 */
2370 s2 = new_stmt(cstate, BPF_ST);
2371 s2->s.k = cstate->off_linkhdr.reg;
2372 sappend(s1, s2);
2373
2374 /*
2375 * Now move it into the X register.
2376 */
2377 s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2378 sappend(s1, s2);
2379
2380 return (s1);
2381 } else
2382 return (NULL);
2383}
2384
2385static struct slist *
2386gen_load_radiotap_llprefixlen(compiler_state_t *cstate)
2387{
2388 struct slist *s1, *s2;
2389
2390 /*
2391 * Generate code to load the length of the radiotap header into
2392 * the register assigned to hold that length, if one has been
2393 * assigned. (If one hasn't been assigned, no code we've
2394 * generated uses that prefix, so we don't need to generate any
2395 * code to load it.)
2396 */
2397 if (cstate->off_linkhdr.reg != -1) {
2398 /*
2399 * The 2 bytes at offsets of 2 and 3 from the beginning
2400 * of the radiotap header are the length of the radiotap
2401 * header; unfortunately, it's little-endian, so we have
2402 * to load it a byte at a time and construct the value.
2403 */
2404
2405 /*
2406 * Load the high-order byte, at an offset of 3, shift it
2407 * left a byte, and put the result in the X register.
2408 */
2409 s1 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
2410 s1->s.k = 3;
2411 s2 = new_stmt(cstate, BPF_ALU|BPF_LSH|BPF_K);
2412 sappend(s1, s2);
2413 s2->s.k = 8;
2414 s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2415 sappend(s1, s2);
2416
2417 /*
2418 * Load the next byte, at an offset of 2, and OR the
2419 * value from the X register into it.
2420 */
2421 s2 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
2422 sappend(s1, s2);
2423 s2->s.k = 2;
2424 s2 = new_stmt(cstate, BPF_ALU|BPF_OR|BPF_X);
2425 sappend(s1, s2);
2426
2427 /*
2428 * Now allocate a register to hold that value and store
2429 * it.
2430 */
2431 s2 = new_stmt(cstate, BPF_ST);
2432 s2->s.k = cstate->off_linkhdr.reg;
2433 sappend(s1, s2);
2434
2435 /*
2436 * Now move it into the X register.
2437 */
2438 s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2439 sappend(s1, s2);
2440
2441 return (s1);
2442 } else
2443 return (NULL);
2444}
2445
2446/*
2447 * At the moment we treat PPI as normal Radiotap encoded
2448 * packets. The difference is in the function that generates
2449 * the code at the beginning to compute the header length.
2450 * Since this code generator of PPI supports bare 802.11
2451 * encapsulation only (i.e. the encapsulated DLT should be
2452 * DLT_IEEE802_11) we generate code to check for this too;
2453 * that's done in finish_parse().
2454 */
2455static struct slist *
2456gen_load_ppi_llprefixlen(compiler_state_t *cstate)
2457{
2458 struct slist *s1, *s2;
2459
2460 /*
2461 * Generate code to load the length of the radiotap header
2462 * into the register assigned to hold that length, if one has
2463 * been assigned.
2464 */
2465 if (cstate->off_linkhdr.reg != -1) {
2466 /*
2467 * The 2 bytes at offsets of 2 and 3 from the beginning
2468 * of the radiotap header are the length of the radiotap
2469 * header; unfortunately, it's little-endian, so we have
2470 * to load it a byte at a time and construct the value.
2471 */
2472
2473 /*
2474 * Load the high-order byte, at an offset of 3, shift it
2475 * left a byte, and put the result in the X register.
2476 */
2477 s1 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
2478 s1->s.k = 3;
2479 s2 = new_stmt(cstate, BPF_ALU|BPF_LSH|BPF_K);
2480 sappend(s1, s2);
2481 s2->s.k = 8;
2482 s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2483 sappend(s1, s2);
2484
2485 /*
2486 * Load the next byte, at an offset of 2, and OR the
2487 * value from the X register into it.
2488 */
2489 s2 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
2490 sappend(s1, s2);
2491 s2->s.k = 2;
2492 s2 = new_stmt(cstate, BPF_ALU|BPF_OR|BPF_X);
2493 sappend(s1, s2);
2494
2495 /*
2496 * Now allocate a register to hold that value and store
2497 * it.
2498 */
2499 s2 = new_stmt(cstate, BPF_ST);
2500 s2->s.k = cstate->off_linkhdr.reg;
2501 sappend(s1, s2);
2502
2503 /*
2504 * Now move it into the X register.
2505 */
2506 s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2507 sappend(s1, s2);
2508
2509 return (s1);
2510 } else
2511 return (NULL);
2512}
2513
2514/*
2515 * Load a value relative to the beginning of the link-layer header after the 802.11
2516 * header, i.e. LLC_SNAP.
2517 * The link-layer header doesn't necessarily begin at the beginning
2518 * of the packet data; there might be a variable-length prefix containing
2519 * radio information.
2520 */
2521static struct slist *
2522gen_load_802_11_header_len(compiler_state_t *cstate, struct slist *s, struct slist *snext)
2523{
2524 struct slist *s2;
2525 struct slist *sjset_data_frame_1;
2526 struct slist *sjset_data_frame_2;
2527 struct slist *sjset_qos;
2528 struct slist *sjset_radiotap_flags_present;
2529 struct slist *sjset_radiotap_ext_present;
2530 struct slist *sjset_radiotap_tsft_present;
2531 struct slist *sjset_tsft_datapad, *sjset_notsft_datapad;
2532 struct slist *s_roundup;
2533
2534 if (cstate->off_linkpl.reg == -1) {
2535 /*
2536 * No register has been assigned to the offset of
2537 * the link-layer payload, which means nobody needs
2538 * it; don't bother computing it - just return
2539 * what we already have.
2540 */
2541 return (s);
2542 }
2543
2544 /*
2545 * This code is not compatible with the optimizer, as
2546 * we are generating jmp instructions within a normal
2547 * slist of instructions
2548 */
2549 cstate->no_optimize = 1;
2550
2551 /*
2552 * If "s" is non-null, it has code to arrange that the X register
2553 * contains the length of the prefix preceding the link-layer
2554 * header.
2555 *
2556 * Otherwise, the length of the prefix preceding the link-layer
2557 * header is "off_outermostlinkhdr.constant_part".
2558 */
2559 if (s == NULL) {
2560 /*
2561 * There is no variable-length header preceding the
2562 * link-layer header.
2563 *
2564 * Load the length of the fixed-length prefix preceding
2565 * the link-layer header (if any) into the X register,
2566 * and store it in the cstate->off_linkpl.reg register.
2567 * That length is off_outermostlinkhdr.constant_part.
2568 */
2569 s = new_stmt(cstate, BPF_LDX|BPF_IMM);
2570 s->s.k = cstate->off_outermostlinkhdr.constant_part;
2571 }
2572
2573 /*
2574 * The X register contains the offset of the beginning of the
2575 * link-layer header; add 24, which is the minimum length
2576 * of the MAC header for a data frame, to that, and store it
2577 * in cstate->off_linkpl.reg, and then load the Frame Control field,
2578 * which is at the offset in the X register, with an indexed load.
2579 */
2580 s2 = new_stmt(cstate, BPF_MISC|BPF_TXA);
2581 sappend(s, s2);
2582 s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
2583 s2->s.k = 24;
2584 sappend(s, s2);
2585 s2 = new_stmt(cstate, BPF_ST);
2586 s2->s.k = cstate->off_linkpl.reg;
2587 sappend(s, s2);
2588
2589 s2 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
2590 s2->s.k = 0;
2591 sappend(s, s2);
2592
2593 /*
2594 * Check the Frame Control field to see if this is a data frame;
2595 * a data frame has the 0x08 bit (b3) in that field set and the
2596 * 0x04 bit (b2) clear.
2597 */
2598 sjset_data_frame_1 = new_stmt(cstate, JMP(BPF_JSET));
2599 sjset_data_frame_1->s.k = 0x08;
2600 sappend(s, sjset_data_frame_1);
2601
2602 /*
2603 * If b3 is set, test b2, otherwise go to the first statement of
2604 * the rest of the program.
2605 */
2606 sjset_data_frame_1->s.jt = sjset_data_frame_2 = new_stmt(cstate, JMP(BPF_JSET));
2607 sjset_data_frame_2->s.k = 0x04;
2608 sappend(s, sjset_data_frame_2);
2609 sjset_data_frame_1->s.jf = snext;
2610
2611 /*
2612 * If b2 is not set, this is a data frame; test the QoS bit.
2613 * Otherwise, go to the first statement of the rest of the
2614 * program.
2615 */
2616 sjset_data_frame_2->s.jt = snext;
2617 sjset_data_frame_2->s.jf = sjset_qos = new_stmt(cstate, JMP(BPF_JSET));
2618 sjset_qos->s.k = 0x80; /* QoS bit */
2619 sappend(s, sjset_qos);
2620
2621 /*
2622 * If it's set, add 2 to cstate->off_linkpl.reg, to skip the QoS
2623 * field.
2624 * Otherwise, go to the first statement of the rest of the
2625 * program.
2626 */
2627 sjset_qos->s.jt = s2 = new_stmt(cstate, BPF_LD|BPF_MEM);
2628 s2->s.k = cstate->off_linkpl.reg;
2629 sappend(s, s2);
2630 s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_IMM);
2631 s2->s.k = 2;
2632 sappend(s, s2);
2633 s2 = new_stmt(cstate, BPF_ST);
2634 s2->s.k = cstate->off_linkpl.reg;
2635 sappend(s, s2);
2636
2637 /*
2638 * If we have a radiotap header, look at it to see whether
2639 * there's Atheros padding between the MAC-layer header
2640 * and the payload.
2641 *
2642 * Note: all of the fields in the radiotap header are
2643 * little-endian, so we byte-swap all of the values
2644 * we test against, as they will be loaded as big-endian
2645 * values.
2646 *
2647 * XXX - in the general case, we would have to scan through
2648 * *all* the presence bits, if there's more than one word of
2649 * presence bits. That would require a loop, meaning that
2650 * we wouldn't be able to run the filter in the kernel.
2651 *
2652 * We assume here that the Atheros adapters that insert the
2653 * annoying padding don't have multiple antennae and therefore
2654 * do not generate radiotap headers with multiple presence words.
2655 */
2656 if (cstate->linktype == DLT_IEEE802_11_RADIO) {
2657 /*
2658 * Is the IEEE80211_RADIOTAP_FLAGS bit (0x0000002) set
2659 * in the first presence flag word?
2660 */
2661 sjset_qos->s.jf = s2 = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_W);
2662 s2->s.k = 4;
2663 sappend(s, s2);
2664
2665 sjset_radiotap_flags_present = new_stmt(cstate, JMP(BPF_JSET));
2666 sjset_radiotap_flags_present->s.k = SWAPLONG(0x00000002);
2667 sappend(s, sjset_radiotap_flags_present);
2668
2669 /*
2670 * If not, skip all of this.
2671 */
2672 sjset_radiotap_flags_present->s.jf = snext;
2673
2674 /*
2675 * Otherwise, is the "extension" bit set in that word?
2676 */
2677 sjset_radiotap_ext_present = new_stmt(cstate, JMP(BPF_JSET));
2678 sjset_radiotap_ext_present->s.k = SWAPLONG(0x80000000);
2679 sappend(s, sjset_radiotap_ext_present);
2680 sjset_radiotap_flags_present->s.jt = sjset_radiotap_ext_present;
2681
2682 /*
2683 * If so, skip all of this.
2684 */
2685 sjset_radiotap_ext_present->s.jt = snext;
2686
2687 /*
2688 * Otherwise, is the IEEE80211_RADIOTAP_TSFT bit set?
2689 */
2690 sjset_radiotap_tsft_present = new_stmt(cstate, JMP(BPF_JSET));
2691 sjset_radiotap_tsft_present->s.k = SWAPLONG(0x00000001);
2692 sappend(s, sjset_radiotap_tsft_present);
2693 sjset_radiotap_ext_present->s.jf = sjset_radiotap_tsft_present;
2694
2695 /*
2696 * If IEEE80211_RADIOTAP_TSFT is set, the flags field is
2697 * at an offset of 16 from the beginning of the raw packet
2698 * data (8 bytes for the radiotap header and 8 bytes for
2699 * the TSFT field).
2700 *
2701 * Test whether the IEEE80211_RADIOTAP_F_DATAPAD bit (0x20)
2702 * is set.
2703 */
2704 s2 = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B);
2705 s2->s.k = 16;
2706 sappend(s, s2);
2707 sjset_radiotap_tsft_present->s.jt = s2;
2708
2709 sjset_tsft_datapad = new_stmt(cstate, JMP(BPF_JSET));
2710 sjset_tsft_datapad->s.k = 0x20;
2711 sappend(s, sjset_tsft_datapad);
2712
2713 /*
2714 * If IEEE80211_RADIOTAP_TSFT is not set, the flags field is
2715 * at an offset of 8 from the beginning of the raw packet
2716 * data (8 bytes for the radiotap header).
2717 *
2718 * Test whether the IEEE80211_RADIOTAP_F_DATAPAD bit (0x20)
2719 * is set.
2720 */
2721 s2 = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B);
2722 s2->s.k = 8;
2723 sappend(s, s2);
2724 sjset_radiotap_tsft_present->s.jf = s2;
2725
2726 sjset_notsft_datapad = new_stmt(cstate, JMP(BPF_JSET));
2727 sjset_notsft_datapad->s.k = 0x20;
2728 sappend(s, sjset_notsft_datapad);
2729
2730 /*
2731 * In either case, if IEEE80211_RADIOTAP_F_DATAPAD is
2732 * set, round the length of the 802.11 header to
2733 * a multiple of 4. Do that by adding 3 and then
2734 * dividing by and multiplying by 4, which we do by
2735 * ANDing with ~3.
2736 */
2737 s_roundup = new_stmt(cstate, BPF_LD|BPF_MEM);
2738 s_roundup->s.k = cstate->off_linkpl.reg;
2739 sappend(s, s_roundup);
2740 s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_IMM);
2741 s2->s.k = 3;
2742 sappend(s, s2);
2743 s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_IMM);
2744 s2->s.k = ~3;
2745 sappend(s, s2);
2746 s2 = new_stmt(cstate, BPF_ST);
2747 s2->s.k = cstate->off_linkpl.reg;
2748 sappend(s, s2);
2749
2750 sjset_tsft_datapad->s.jt = s_roundup;
2751 sjset_tsft_datapad->s.jf = snext;
2752 sjset_notsft_datapad->s.jt = s_roundup;
2753 sjset_notsft_datapad->s.jf = snext;
2754 } else
2755 sjset_qos->s.jf = snext;
2756
2757 return s;
2758}
2759
2760static void
2761insert_compute_vloffsets(compiler_state_t *cstate, struct block *b)
2762{
2763 struct slist *s;
2764
2765 /* There is an implicit dependency between the link
2766 * payload and link header since the payload computation
2767 * includes the variable part of the header. Therefore,
2768 * if nobody else has allocated a register for the link
2769 * header and we need it, do it now. */
2770 if (cstate->off_linkpl.reg != -1 && cstate->off_linkhdr.is_variable &&
2771 cstate->off_linkhdr.reg == -1)
2772 cstate->off_linkhdr.reg = alloc_reg(cstate);
2773
2774 /*
2775 * For link-layer types that have a variable-length header
2776 * preceding the link-layer header, generate code to load
2777 * the offset of the link-layer header into the register
2778 * assigned to that offset, if any.
2779 *
2780 * XXX - this, and the next switch statement, won't handle
2781 * encapsulation of 802.11 or 802.11+radio information in
2782 * some other protocol stack. That's significantly more
2783 * complicated.
2784 */
2785 switch (cstate->outermostlinktype) {
2786
2787 case DLT_PRISM_HEADER:
2788 s = gen_load_prism_llprefixlen(cstate);
2789 break;
2790
2791 case DLT_IEEE802_11_RADIO_AVS:
2792 s = gen_load_avs_llprefixlen(cstate);
2793 break;
2794
2795 case DLT_IEEE802_11_RADIO:
2796 s = gen_load_radiotap_llprefixlen(cstate);
2797 break;
2798
2799 case DLT_PPI:
2800 s = gen_load_ppi_llprefixlen(cstate);
2801 break;
2802
2803 default:
2804 s = NULL;
2805 break;
2806 }
2807
2808 /*
2809 * For link-layer types that have a variable-length link-layer
2810 * header, generate code to load the offset of the link-layer
2811 * payload into the register assigned to that offset, if any.
2812 */
2813 switch (cstate->outermostlinktype) {
2814
2815 case DLT_IEEE802_11:
2816 case DLT_PRISM_HEADER:
2817 case DLT_IEEE802_11_RADIO_AVS:
2818 case DLT_IEEE802_11_RADIO:
2819 case DLT_PPI:
2820 s = gen_load_802_11_header_len(cstate, s, b->stmts);
2821 break;
2822 }
2823
2824 /*
2825 * If there there is no initialization yet and we need variable
2826 * length offsets for VLAN, initialize them to zero
2827 */
2828 if (s == NULL && cstate->is_vlan_vloffset) {
2829 struct slist *s2;
2830
2831 if (cstate->off_linkpl.reg == -1)
2832 cstate->off_linkpl.reg = alloc_reg(cstate);
2833 if (cstate->off_linktype.reg == -1)
2834 cstate->off_linktype.reg = alloc_reg(cstate);
2835
2836 s = new_stmt(cstate, BPF_LD|BPF_W|BPF_IMM);
2837 s->s.k = 0;
2838 s2 = new_stmt(cstate, BPF_ST);
2839 s2->s.k = cstate->off_linkpl.reg;
2840 sappend(s, s2);
2841 s2 = new_stmt(cstate, BPF_ST);
2842 s2->s.k = cstate->off_linktype.reg;
2843 sappend(s, s2);
2844 }
2845
2846 /*
2847 * If we have any offset-loading code, append all the
2848 * existing statements in the block to those statements,
2849 * and make the resulting list the list of statements
2850 * for the block.
2851 */
2852 if (s != NULL) {
2853 sappend(s, b->stmts);
2854 b->stmts = s;
2855 }
2856}
2857
2858static struct block *
2859gen_ppi_dlt_check(compiler_state_t *cstate)
2860{
2861 struct slist *s_load_dlt;
2862 struct block *b;
2863
2864 if (cstate->linktype == DLT_PPI)
2865 {
2866 /* Create the statements that check for the DLT
2867 */
2868 s_load_dlt = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
2869 s_load_dlt->s.k = 4;
2870
2871 b = new_block(cstate, JMP(BPF_JEQ));
2872
2873 b->stmts = s_load_dlt;
2874 b->s.k = SWAPLONG(DLT_IEEE802_11);
2875 }
2876 else
2877 {
2878 b = NULL;
2879 }
2880
2881 return b;
2882}
2883
2884/*
2885 * Take an absolute offset, and:
2886 *
2887 * if it has no variable part, return NULL;
2888 *
2889 * if it has a variable part, generate code to load the register
2890 * containing that variable part into the X register, returning
2891 * a pointer to that code - if no register for that offset has
2892 * been allocated, allocate it first.
2893 *
2894 * (The code to set that register will be generated later, but will
2895 * be placed earlier in the code sequence.)
2896 */
2897static struct slist *
2898gen_abs_offset_varpart(compiler_state_t *cstate, bpf_abs_offset *off)
2899{
2900 struct slist *s;
2901
2902 if (off->is_variable) {
2903 if (off->reg == -1) {
2904 /*
2905 * We haven't yet assigned a register for the
2906 * variable part of the offset of the link-layer
2907 * header; allocate one.
2908 */
2909 off->reg = alloc_reg(cstate);
2910 }
2911
2912 /*
2913 * Load the register containing the variable part of the
2914 * offset of the link-layer header into the X register.
2915 */
2916 s = new_stmt(cstate, BPF_LDX|BPF_MEM);
2917 s->s.k = off->reg;
2918 return s;
2919 } else {
2920 /*
2921 * That offset isn't variable, there's no variable part,
2922 * so we don't need to generate any code.
2923 */
2924 return NULL;
2925 }
2926}
2927
2928/*
2929 * Map an Ethernet type to the equivalent PPP type.
2930 */
2931static int
2932ethertype_to_ppptype(int proto)
2933{
2934 switch (proto) {
2935
2936 case ETHERTYPE_IP:
2937 proto = PPP_IP;
2938 break;
2939
2940 case ETHERTYPE_IPV6:
2941 proto = PPP_IPV6;
2942 break;
2943
2944 case ETHERTYPE_DN:
2945 proto = PPP_DECNET;
2946 break;
2947
2948 case ETHERTYPE_ATALK:
2949 proto = PPP_APPLE;
2950 break;
2951
2952 case ETHERTYPE_NS:
2953 proto = PPP_NS;
2954 break;
2955
2956 case LLCSAP_ISONS:
2957 proto = PPP_OSI;
2958 break;
2959
2960 case LLCSAP_8021D:
2961 /*
2962 * I'm assuming the "Bridging PDU"s that go
2963 * over PPP are Spanning Tree Protocol
2964 * Bridging PDUs.
2965 */
2966 proto = PPP_BRPDU;
2967 break;
2968
2969 case LLCSAP_IPX:
2970 proto = PPP_IPX;
2971 break;
2972 }
2973 return (proto);
2974}
2975
2976/*
2977 * Generate any tests that, for encapsulation of a link-layer packet
2978 * inside another protocol stack, need to be done to check for those
2979 * link-layer packets (and that haven't already been done by a check
2980 * for that encapsulation).
2981 */
2982static struct block *
2983gen_prevlinkhdr_check(compiler_state_t *cstate)
2984{
2985 struct block *b0;
2986
2987 if (cstate->is_geneve)
2988 return gen_geneve_ll_check(cstate);
2989
2990 switch (cstate->prevlinktype) {
2991
2992 case DLT_SUNATM:
2993 /*
2994 * This is LANE-encapsulated Ethernet; check that the LANE
2995 * packet doesn't begin with an LE Control marker, i.e.
2996 * that it's data, not a control message.
2997 *
2998 * (We've already generated a test for LANE.)
2999 */
3000 b0 = gen_cmp(cstate, OR_PREVLINKHDR, SUNATM_PKT_BEGIN_POS, BPF_H, 0xFF00);
3001 gen_not(b0);
3002 return b0;
3003
3004 default:
3005 /*
3006 * No such tests are necessary.
3007 */
3008 return NULL;
3009 }
3010 /*NOTREACHED*/
3011}
3012
3013/*
3014 * The three different values we should check for when checking for an
3015 * IPv6 packet with DLT_NULL.
3016 */
3017#define BSD_AFNUM_INET6_BSD 24 /* NetBSD, OpenBSD, BSD/OS, Npcap */
3018#define BSD_AFNUM_INET6_FREEBSD 28 /* FreeBSD */
3019#define BSD_AFNUM_INET6_DARWIN 30 /* macOS, iOS, other Darwin-based OSes */
3020
3021/*
3022 * Generate code to match a particular packet type by matching the
3023 * link-layer type field or fields in the 802.2 LLC header.
3024 *
3025 * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
3026 * value, if <= ETHERMTU.
3027 */
3028static struct block *
3029gen_linktype(compiler_state_t *cstate, int proto)
3030{
3031 struct block *b0, *b1, *b2;
3032 const char *description;
3033
3034 /* are we checking MPLS-encapsulated packets? */
3035 if (cstate->label_stack_depth > 0) {
3036 switch (proto) {
3037 case ETHERTYPE_IP:
3038 case PPP_IP:
3039 /* FIXME add other L3 proto IDs */
3040 return gen_mpls_linktype(cstate, Q_IP);
3041
3042 case ETHERTYPE_IPV6:
3043 case PPP_IPV6:
3044 /* FIXME add other L3 proto IDs */
3045 return gen_mpls_linktype(cstate, Q_IPV6);
3046
3047 default:
3048 bpf_error(cstate, "unsupported protocol over mpls");
3049 /* NOTREACHED */
3050 }
3051 }
3052
3053 switch (cstate->linktype) {
3054
3055 case DLT_EN10MB:
3056 case DLT_NETANALYZER:
3057 case DLT_NETANALYZER_TRANSPARENT:
3058 /* Geneve has an EtherType regardless of whether there is an
3059 * L2 header. */
3060 if (!cstate->is_geneve)
3061 b0 = gen_prevlinkhdr_check(cstate);
3062 else
3063 b0 = NULL;
3064
3065 b1 = gen_ether_linktype(cstate, proto);
3066 if (b0 != NULL)
3067 gen_and(b0, b1);
3068 return b1;
3069 /*NOTREACHED*/
3070 break;
3071
3072 case DLT_C_HDLC:
3073 switch (proto) {
3074
3075 case LLCSAP_ISONS:
3076 proto = (proto << 8 | LLCSAP_ISONS);
3077 /* fall through */
3078
3079 default:
3080 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
3081 /*NOTREACHED*/
3082 break;
3083 }
3084 break;
3085
3086 case DLT_IEEE802_11:
3087 case DLT_PRISM_HEADER:
3088 case DLT_IEEE802_11_RADIO_AVS:
3089 case DLT_IEEE802_11_RADIO:
3090 case DLT_PPI:
3091 /*
3092 * Check that we have a data frame.
3093 */
3094 b0 = gen_check_802_11_data_frame(cstate);
3095
3096 /*
3097 * Now check for the specified link-layer type.
3098 */
3099 b1 = gen_llc_linktype(cstate, proto);
3100 gen_and(b0, b1);
3101 return b1;
3102 /*NOTREACHED*/
3103 break;
3104
3105 case DLT_FDDI:
3106 /*
3107 * XXX - check for LLC frames.
3108 */
3109 return gen_llc_linktype(cstate, proto);
3110 /*NOTREACHED*/
3111 break;
3112
3113 case DLT_IEEE802:
3114 /*
3115 * XXX - check for LLC PDUs, as per IEEE 802.5.
3116 */
3117 return gen_llc_linktype(cstate, proto);
3118 /*NOTREACHED*/
3119 break;
3120
3121 case DLT_ATM_RFC1483:
3122 case DLT_ATM_CLIP:
3123 case DLT_IP_OVER_FC:
3124 return gen_llc_linktype(cstate, proto);
3125 /*NOTREACHED*/
3126 break;
3127
3128 case DLT_SUNATM:
3129 /*
3130 * Check for an LLC-encapsulated version of this protocol;
3131 * if we were checking for LANE, linktype would no longer
3132 * be DLT_SUNATM.
3133 *
3134 * Check for LLC encapsulation and then check the protocol.
3135 */
3136 b0 = gen_atmfield_code(cstate, A_PROTOTYPE, PT_LLC, BPF_JEQ, 0);
3137 b1 = gen_llc_linktype(cstate, proto);
3138 gen_and(b0, b1);
3139 return b1;
3140 /*NOTREACHED*/
3141 break;
3142
3143 case DLT_LINUX_SLL:
3144 return gen_linux_sll_linktype(cstate, proto);
3145 /*NOTREACHED*/
3146 break;
3147
3148 case DLT_SLIP:
3149 case DLT_SLIP_BSDOS:
3150 case DLT_RAW:
3151 /*
3152 * These types don't provide any type field; packets
3153 * are always IPv4 or IPv6.
3154 *
3155 * XXX - for IPv4, check for a version number of 4, and,
3156 * for IPv6, check for a version number of 6?
3157 */
3158 switch (proto) {
3159
3160 case ETHERTYPE_IP:
3161 /* Check for a version number of 4. */
3162 return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, 0x40, 0xF0);
3163
3164 case ETHERTYPE_IPV6:
3165 /* Check for a version number of 6. */
3166 return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, 0x60, 0xF0);
3167
3168 default:
3169 return gen_false(cstate); /* always false */
3170 }
3171 /*NOTREACHED*/
3172 break;
3173
3174 case DLT_IPV4:
3175 /*
3176 * Raw IPv4, so no type field.
3177 */
3178 if (proto == ETHERTYPE_IP)
3179 return gen_true(cstate); /* always true */
3180
3181 /* Checking for something other than IPv4; always false */
3182 return gen_false(cstate);
3183 /*NOTREACHED*/
3184 break;
3185
3186 case DLT_IPV6:
3187 /*
3188 * Raw IPv6, so no type field.
3189 */
3190 if (proto == ETHERTYPE_IPV6)
3191 return gen_true(cstate); /* always true */
3192
3193 /* Checking for something other than IPv6; always false */
3194 return gen_false(cstate);
3195 /*NOTREACHED*/
3196 break;
3197
3198 case DLT_PPP:
3199 case DLT_PPP_PPPD:
3200 case DLT_PPP_SERIAL:
3201 case DLT_PPP_ETHER:
3202 /*
3203 * We use Ethernet protocol types inside libpcap;
3204 * map them to the corresponding PPP protocol types.
3205 */
3206 proto = ethertype_to_ppptype(proto);
3207 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
3208 /*NOTREACHED*/
3209 break;
3210
3211 case DLT_PPP_BSDOS:
3212 /*
3213 * We use Ethernet protocol types inside libpcap;
3214 * map them to the corresponding PPP protocol types.
3215 */
3216 switch (proto) {
3217
3218 case ETHERTYPE_IP:
3219 /*
3220 * Also check for Van Jacobson-compressed IP.
3221 * XXX - do this for other forms of PPP?
3222 */
3223 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, PPP_IP);
3224 b1 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, PPP_VJC);
3225 gen_or(b0, b1);
3226 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, PPP_VJNC);
3227 gen_or(b1, b0);
3228 return b0;
3229
3230 default:
3231 proto = ethertype_to_ppptype(proto);
3232 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H,
3233 (bpf_int32)proto);
3234 }
3235 /*NOTREACHED*/
3236 break;
3237
3238 case DLT_NULL:
3239 case DLT_LOOP:
3240 case DLT_ENC:
3241 switch (proto) {
3242
3243 case ETHERTYPE_IP:
3244 return (gen_loopback_linktype(cstate, AF_INET));
3245
3246 case ETHERTYPE_IPV6:
3247 /*
3248 * AF_ values may, unfortunately, be platform-
3249 * dependent; AF_INET isn't, because everybody
3250 * used 4.2BSD's value, but AF_INET6 is, because
3251 * 4.2BSD didn't have a value for it (given that
3252 * IPv6 didn't exist back in the early 1980's),
3253 * and they all picked their own values.
3254 *
3255 * This means that, if we're reading from a
3256 * savefile, we need to check for all the
3257 * possible values.
3258 *
3259 * If we're doing a live capture, we only need
3260 * to check for this platform's value; however,
3261 * Npcap uses 24, which isn't Windows's AF_INET6
3262 * value. (Given the multiple different values,
3263 * programs that read pcap files shouldn't be
3264 * checking for their platform's AF_INET6 value
3265 * anyway, they should check for all of the
3266 * possible values. and they might as well do
3267 * that even for live captures.)
3268 */
3269 if (cstate->bpf_pcap->rfile != NULL) {
3270 /*
3271 * Savefile - check for all three
3272 * possible IPv6 values.
3273 */
3274 b0 = gen_loopback_linktype(cstate, BSD_AFNUM_INET6_BSD);
3275 b1 = gen_loopback_linktype(cstate, BSD_AFNUM_INET6_FREEBSD);
3276 gen_or(b0, b1);
3277 b0 = gen_loopback_linktype(cstate, BSD_AFNUM_INET6_DARWIN);
3278 gen_or(b0, b1);
3279 return (b1);
3280 } else {
3281 /*
3282 * Live capture, so we only need to
3283 * check for the value used on this
3284 * platform.
3285 */
3286#ifdef _WIN32
3287 /*
3288 * Npcap doesn't use Windows's AF_INET6,
3289 * as that collides with AF_IPX on
3290 * some BSDs (both have the value 23).
3291 * Instead, it uses 24.
3292 */
3293 return (gen_loopback_linktype(cstate, 24));
3294#else /* _WIN32 */
3295#ifdef AF_INET6
3296 return (gen_loopback_linktype(cstate, AF_INET6));
3297#else /* AF_INET6 */
3298 /*
3299 * I guess this platform doesn't support
3300 * IPv6, so we just reject all packets.
3301 */
3302 return gen_false(cstate);
3303#endif /* AF_INET6 */
3304#endif /* _WIN32 */
3305 }
3306
3307 default:
3308 /*
3309 * Not a type on which we support filtering.
3310 * XXX - support those that have AF_ values
3311 * #defined on this platform, at least?
3312 */
3313 return gen_false(cstate);
3314 }
3315
3316#ifdef HAVE_NET_PFVAR_H
3317 case DLT_PFLOG:
3318 /*
3319 * af field is host byte order in contrast to the rest of
3320 * the packet.
3321 */
3322 if (proto == ETHERTYPE_IP)
3323 return (gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, af),
3324 BPF_B, (bpf_int32)AF_INET));
3325 else if (proto == ETHERTYPE_IPV6)
3326 return (gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, af),
3327 BPF_B, (bpf_int32)AF_INET6));
3328 else
3329 return gen_false(cstate);
3330 /*NOTREACHED*/
3331 break;
3332#endif /* HAVE_NET_PFVAR_H */
3333
3334 case DLT_ARCNET:
3335 case DLT_ARCNET_LINUX:
3336 /*
3337 * XXX should we check for first fragment if the protocol
3338 * uses PHDS?
3339 */
3340 switch (proto) {
3341
3342 default:
3343 return gen_false(cstate);
3344
3345 case ETHERTYPE_IPV6:
3346 return (gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3347 (bpf_int32)ARCTYPE_INET6));
3348
3349 case ETHERTYPE_IP:
3350 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3351 (bpf_int32)ARCTYPE_IP);
3352 b1 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3353 (bpf_int32)ARCTYPE_IP_OLD);
3354 gen_or(b0, b1);
3355 return (b1);
3356
3357 case ETHERTYPE_ARP:
3358 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3359 (bpf_int32)ARCTYPE_ARP);
3360 b1 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3361 (bpf_int32)ARCTYPE_ARP_OLD);
3362 gen_or(b0, b1);
3363 return (b1);
3364
3365 case ETHERTYPE_REVARP:
3366 return (gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3367 (bpf_int32)ARCTYPE_REVARP));
3368
3369 case ETHERTYPE_ATALK:
3370 return (gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3371 (bpf_int32)ARCTYPE_ATALK));
3372 }
3373 /*NOTREACHED*/
3374 break;
3375
3376 case DLT_LTALK:
3377 switch (proto) {
3378 case ETHERTYPE_ATALK:
3379 return gen_true(cstate);
3380 default:
3381 return gen_false(cstate);
3382 }
3383 /*NOTREACHED*/
3384 break;
3385
3386 case DLT_FRELAY:
3387 /*
3388 * XXX - assumes a 2-byte Frame Relay header with
3389 * DLCI and flags. What if the address is longer?
3390 */
3391 switch (proto) {
3392
3393 case ETHERTYPE_IP:
3394 /*
3395 * Check for the special NLPID for IP.
3396 */
3397 return gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | 0xcc);
3398
3399 case ETHERTYPE_IPV6:
3400 /*
3401 * Check for the special NLPID for IPv6.
3402 */
3403 return gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | 0x8e);
3404
3405 case LLCSAP_ISONS:
3406 /*
3407 * Check for several OSI protocols.
3408 *
3409 * Frame Relay packets typically have an OSI
3410 * NLPID at the beginning; we check for each
3411 * of them.
3412 *
3413 * What we check for is the NLPID and a frame
3414 * control field of UI, i.e. 0x03 followed
3415 * by the NLPID.
3416 */
3417 b0 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | ISO8473_CLNP);
3418 b1 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | ISO9542_ESIS);
3419 b2 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | ISO10589_ISIS);
3420 gen_or(b1, b2);
3421 gen_or(b0, b2);
3422 return b2;
3423
3424 default:
3425 return gen_false(cstate);
3426 }
3427 /*NOTREACHED*/
3428 break;
3429
3430 case DLT_MFR:
3431 bpf_error(cstate, "Multi-link Frame Relay link-layer type filtering not implemented");
3432
3433 case DLT_JUNIPER_MFR:
3434 case DLT_JUNIPER_MLFR:
3435 case DLT_JUNIPER_MLPPP:
3436 case DLT_JUNIPER_ATM1:
3437 case DLT_JUNIPER_ATM2:
3438 case DLT_JUNIPER_PPPOE:
3439 case DLT_JUNIPER_PPPOE_ATM:
3440 case DLT_JUNIPER_GGSN:
3441 case DLT_JUNIPER_ES:
3442 case DLT_JUNIPER_MONITOR:
3443 case DLT_JUNIPER_SERVICES:
3444 case DLT_JUNIPER_ETHER:
3445 case DLT_JUNIPER_PPP:
3446 case DLT_JUNIPER_FRELAY:
3447 case DLT_JUNIPER_CHDLC:
3448 case DLT_JUNIPER_VP:
3449 case DLT_JUNIPER_ST:
3450 case DLT_JUNIPER_ISM:
3451 case DLT_JUNIPER_VS:
3452 case DLT_JUNIPER_SRX_E2E:
3453 case DLT_JUNIPER_FIBRECHANNEL:
3454 case DLT_JUNIPER_ATM_CEMIC:
3455
3456 /* just lets verify the magic number for now -
3457 * on ATM we may have up to 6 different encapsulations on the wire
3458 * and need a lot of heuristics to figure out that the payload
3459 * might be;
3460 *
3461 * FIXME encapsulation specific BPF_ filters
3462 */
3463 return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_W, 0x4d474300, 0xffffff00); /* compare the magic number */
3464
3465 case DLT_BACNET_MS_TP:
3466 return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_W, 0x55FF0000, 0xffff0000);
3467
3468 case DLT_IPNET:
3469 return gen_ipnet_linktype(cstate, proto);
3470
3471 case DLT_LINUX_IRDA:
3472 bpf_error(cstate, "IrDA link-layer type filtering not implemented");
3473
3474 case DLT_DOCSIS:
3475 bpf_error(cstate, "DOCSIS link-layer type filtering not implemented");
3476
3477 case DLT_MTP2:
3478 case DLT_MTP2_WITH_PHDR:
3479 bpf_error(cstate, "MTP2 link-layer type filtering not implemented");
3480
3481 case DLT_ERF:
3482 bpf_error(cstate, "ERF link-layer type filtering not implemented");
3483
3484 case DLT_PFSYNC:
3485 bpf_error(cstate, "PFSYNC link-layer type filtering not implemented");
3486
3487 case DLT_LINUX_LAPD:
3488 bpf_error(cstate, "LAPD link-layer type filtering not implemented");
3489
3490 case DLT_USB_FREEBSD:
3491 case DLT_USB_LINUX:
3492 case DLT_USB_LINUX_MMAPPED:
3493 case DLT_USBPCAP:
3494 bpf_error(cstate, "USB link-layer type filtering not implemented");
3495
3496 case DLT_BLUETOOTH_HCI_H4:
3497 case DLT_BLUETOOTH_HCI_H4_WITH_PHDR:
3498 bpf_error(cstate, "Bluetooth link-layer type filtering not implemented");
3499
3500 case DLT_CAN20B:
3501 case DLT_CAN_SOCKETCAN:
3502 bpf_error(cstate, "CAN link-layer type filtering not implemented");
3503
3504 case DLT_IEEE802_15_4:
3505 case DLT_IEEE802_15_4_LINUX:
3506 case DLT_IEEE802_15_4_NONASK_PHY:
3507 case DLT_IEEE802_15_4_NOFCS:
3508 bpf_error(cstate, "IEEE 802.15.4 link-layer type filtering not implemented");
3509
3510 case DLT_IEEE802_16_MAC_CPS_RADIO:
3511 bpf_error(cstate, "IEEE 802.16 link-layer type filtering not implemented");
3512
3513 case DLT_SITA:
3514 bpf_error(cstate, "SITA link-layer type filtering not implemented");
3515
3516 case DLT_RAIF1:
3517 bpf_error(cstate, "RAIF1 link-layer type filtering not implemented");
3518
3519 case DLT_IPMB:
3520 bpf_error(cstate, "IPMB link-layer type filtering not implemented");
3521
3522 case DLT_AX25_KISS:
3523 bpf_error(cstate, "AX.25 link-layer type filtering not implemented");
3524
3525 case DLT_NFLOG:
3526 /* Using the fixed-size NFLOG header it is possible to tell only
3527 * the address family of the packet, other meaningful data is
3528 * either missing or behind TLVs.
3529 */
3530 bpf_error(cstate, "NFLOG link-layer type filtering not implemented");
3531
3532 default:
3533 /*
3534 * Does this link-layer header type have a field
3535 * indicating the type of the next protocol? If
3536 * so, off_linktype.constant_part will be the offset of that
3537 * field in the packet; if not, it will be OFFSET_NOT_SET.
3538 */
3539 if (cstate->off_linktype.constant_part != OFFSET_NOT_SET) {
3540 /*
3541 * Yes; assume it's an Ethernet type. (If
3542 * it's not, it needs to be handled specially
3543 * above.)
3544 */
3545 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
3546 } else {
3547 /*
3548 * No; report an error.
3549 */
3550 description = pcap_datalink_val_to_description(cstate->linktype);
3551 if (description != NULL) {
3552 bpf_error(cstate, "%s link-layer type filtering not implemented",
3553 description);
3554 } else {
3555 bpf_error(cstate, "DLT %u link-layer type filtering not implemented",
3556 cstate->linktype);
3557 }
3558 }
3559 break;
3560 }
3561}
3562
3563/*
3564 * Check for an LLC SNAP packet with a given organization code and
3565 * protocol type; we check the entire contents of the 802.2 LLC and
3566 * snap headers, checking for DSAP and SSAP of SNAP and a control
3567 * field of 0x03 in the LLC header, and for the specified organization
3568 * code and protocol type in the SNAP header.
3569 */
3570static struct block *
3571gen_snap(compiler_state_t *cstate, bpf_u_int32 orgcode, bpf_u_int32 ptype)
3572{
3573 u_char snapblock[8];
3574
3575 snapblock[0] = LLCSAP_SNAP; /* DSAP = SNAP */
3576 snapblock[1] = LLCSAP_SNAP; /* SSAP = SNAP */
3577 snapblock[2] = 0x03; /* control = UI */
3578 snapblock[3] = (u_char)(orgcode >> 16); /* upper 8 bits of organization code */
3579 snapblock[4] = (u_char)(orgcode >> 8); /* middle 8 bits of organization code */
3580 snapblock[5] = (u_char)(orgcode >> 0); /* lower 8 bits of organization code */
3581 snapblock[6] = (u_char)(ptype >> 8); /* upper 8 bits of protocol type */
3582 snapblock[7] = (u_char)(ptype >> 0); /* lower 8 bits of protocol type */
3583 return gen_bcmp(cstate, OR_LLC, 0, 8, snapblock);
3584}
3585
3586/*
3587 * Generate code to match frames with an LLC header.
3588 */
3589struct block *
3590gen_llc(compiler_state_t *cstate)
3591{
3592 struct block *b0, *b1;
3593
3594 switch (cstate->linktype) {
3595
3596 case DLT_EN10MB:
3597 /*
3598 * We check for an Ethernet type field less than
3599 * 1500, which means it's an 802.3 length field.
3600 */
3601 b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
3602 gen_not(b0);
3603
3604 /*
3605 * Now check for the purported DSAP and SSAP not being
3606 * 0xFF, to rule out NetWare-over-802.3.
3607 */
3608 b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_int32)0xFFFF);
3609 gen_not(b1);
3610 gen_and(b0, b1);
3611 return b1;
3612
3613 case DLT_SUNATM:
3614 /*
3615 * We check for LLC traffic.
3616 */
3617 b0 = gen_atmtype_abbrev(cstate, A_LLC);
3618 return b0;
3619
3620 case DLT_IEEE802: /* Token Ring */
3621 /*
3622 * XXX - check for LLC frames.
3623 */
3624 return gen_true(cstate);
3625
3626 case DLT_FDDI:
3627 /*
3628 * XXX - check for LLC frames.
3629 */
3630 return gen_true(cstate);
3631
3632 case DLT_ATM_RFC1483:
3633 /*
3634 * For LLC encapsulation, these are defined to have an
3635 * 802.2 LLC header.
3636 *
3637 * For VC encapsulation, they don't, but there's no
3638 * way to check for that; the protocol used on the VC
3639 * is negotiated out of band.
3640 */
3641 return gen_true(cstate);
3642
3643 case DLT_IEEE802_11:
3644 case DLT_PRISM_HEADER:
3645 case DLT_IEEE802_11_RADIO:
3646 case DLT_IEEE802_11_RADIO_AVS:
3647 case DLT_PPI:
3648 /*
3649 * Check that we have a data frame.
3650 */
3651 b0 = gen_check_802_11_data_frame(cstate);
3652 return b0;
3653
3654 default:
3655 bpf_error(cstate, "'llc' not supported for linktype %d", cstate->linktype);
3656 /* NOTREACHED */
3657 }
3658}
3659
3660struct block *
3661gen_llc_i(compiler_state_t *cstate)
3662{
3663 struct block *b0, *b1;
3664 struct slist *s;
3665
3666 /*
3667 * Check whether this is an LLC frame.
3668 */
3669 b0 = gen_llc(cstate);
3670
3671 /*
3672 * Load the control byte and test the low-order bit; it must
3673 * be clear for I frames.
3674 */
3675 s = gen_load_a(cstate, OR_LLC, 2, BPF_B);
3676 b1 = new_block(cstate, JMP(BPF_JSET));
3677 b1->s.k = 0x01;
3678 b1->stmts = s;
3679 gen_not(b1);
3680 gen_and(b0, b1);
3681 return b1;
3682}
3683
3684struct block *
3685gen_llc_s(compiler_state_t *cstate)
3686{
3687 struct block *b0, *b1;
3688
3689 /*
3690 * Check whether this is an LLC frame.
3691 */
3692 b0 = gen_llc(cstate);
3693
3694 /*
3695 * Now compare the low-order 2 bit of the control byte against
3696 * the appropriate value for S frames.
3697 */
3698 b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, LLC_S_FMT, 0x03);
3699 gen_and(b0, b1);
3700 return b1;
3701}
3702
3703struct block *
3704gen_llc_u(compiler_state_t *cstate)
3705{
3706 struct block *b0, *b1;
3707
3708 /*
3709 * Check whether this is an LLC frame.
3710 */
3711 b0 = gen_llc(cstate);
3712
3713 /*
3714 * Now compare the low-order 2 bit of the control byte against
3715 * the appropriate value for U frames.
3716 */
3717 b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, LLC_U_FMT, 0x03);
3718 gen_and(b0, b1);
3719 return b1;
3720}
3721
3722struct block *
3723gen_llc_s_subtype(compiler_state_t *cstate, bpf_u_int32 subtype)
3724{
3725 struct block *b0, *b1;
3726
3727 /*
3728 * Check whether this is an LLC frame.
3729 */
3730 b0 = gen_llc(cstate);
3731
3732 /*
3733 * Now check for an S frame with the appropriate type.
3734 */
3735 b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, subtype, LLC_S_CMD_MASK);
3736 gen_and(b0, b1);
3737 return b1;
3738}
3739
3740struct block *
3741gen_llc_u_subtype(compiler_state_t *cstate, bpf_u_int32 subtype)
3742{
3743 struct block *b0, *b1;
3744
3745 /*
3746 * Check whether this is an LLC frame.
3747 */
3748 b0 = gen_llc(cstate);
3749
3750 /*
3751 * Now check for a U frame with the appropriate type.
3752 */
3753 b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, subtype, LLC_U_CMD_MASK);
3754 gen_and(b0, b1);
3755 return b1;
3756}
3757
3758/*
3759 * Generate code to match a particular packet type, for link-layer types
3760 * using 802.2 LLC headers.
3761 *
3762 * This is *NOT* used for Ethernet; "gen_ether_linktype()" is used
3763 * for that - it handles the D/I/X Ethernet vs. 802.3+802.2 issues.
3764 *
3765 * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
3766 * value, if <= ETHERMTU. We use that to determine whether to
3767 * match the DSAP or both DSAP and LSAP or to check the OUI and
3768 * protocol ID in a SNAP header.
3769 */
3770static struct block *
3771gen_llc_linktype(compiler_state_t *cstate, int proto)
3772{
3773 /*
3774 * XXX - handle token-ring variable-length header.
3775 */
3776 switch (proto) {
3777
3778 case LLCSAP_IP:
3779 case LLCSAP_ISONS:
3780 case LLCSAP_NETBEUI:
3781 /*
3782 * XXX - should we check both the DSAP and the
3783 * SSAP, like this, or should we check just the
3784 * DSAP, as we do for other SAP values?
3785 */
3786 return gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_u_int32)
3787 ((proto << 8) | proto));
3788
3789 case LLCSAP_IPX:
3790 /*
3791 * XXX - are there ever SNAP frames for IPX on
3792 * non-Ethernet 802.x networks?
3793 */
3794 return gen_cmp(cstate, OR_LLC, 0, BPF_B,
3795 (bpf_int32)LLCSAP_IPX);
3796
3797 case ETHERTYPE_ATALK:
3798 /*
3799 * 802.2-encapsulated ETHERTYPE_ATALK packets are
3800 * SNAP packets with an organization code of
3801 * 0x080007 (Apple, for Appletalk) and a protocol
3802 * type of ETHERTYPE_ATALK (Appletalk).
3803 *
3804 * XXX - check for an organization code of
3805 * encapsulated Ethernet as well?
3806 */
3807 return gen_snap(cstate, 0x080007, ETHERTYPE_ATALK);
3808
3809 default:
3810 /*
3811 * XXX - we don't have to check for IPX 802.3
3812 * here, but should we check for the IPX Ethertype?
3813 */
3814 if (proto <= ETHERMTU) {
3815 /*
3816 * This is an LLC SAP value, so check
3817 * the DSAP.
3818 */
3819 return gen_cmp(cstate, OR_LLC, 0, BPF_B, (bpf_int32)proto);
3820 } else {
3821 /*
3822 * This is an Ethernet type; we assume that it's
3823 * unlikely that it'll appear in the right place
3824 * at random, and therefore check only the
3825 * location that would hold the Ethernet type
3826 * in a SNAP frame with an organization code of
3827 * 0x000000 (encapsulated Ethernet).
3828 *
3829 * XXX - if we were to check for the SNAP DSAP and
3830 * LSAP, as per XXX, and were also to check for an
3831 * organization code of 0x000000 (encapsulated
3832 * Ethernet), we'd do
3833 *
3834 * return gen_snap(cstate, 0x000000, proto);
3835 *
3836 * here; for now, we don't, as per the above.
3837 * I don't know whether it's worth the extra CPU
3838 * time to do the right check or not.
3839 */
3840 return gen_cmp(cstate, OR_LLC, 6, BPF_H, (bpf_int32)proto);
3841 }
3842 }
3843}
3844
3845static struct block *
3846gen_hostop(compiler_state_t *cstate, bpf_u_int32 addr, bpf_u_int32 mask,
3847 int dir, int proto, u_int src_off, u_int dst_off)
3848{
3849 struct block *b0, *b1;
3850 u_int offset;
3851
3852 switch (dir) {
3853
3854 case Q_SRC:
3855 offset = src_off;
3856 break;
3857
3858 case Q_DST:
3859 offset = dst_off;
3860 break;
3861
3862 case Q_AND:
3863 b0 = gen_hostop(cstate, addr, mask, Q_SRC, proto, src_off, dst_off);
3864 b1 = gen_hostop(cstate, addr, mask, Q_DST, proto, src_off, dst_off);
3865 gen_and(b0, b1);
3866 return b1;
3867
3868 case Q_OR:
3869 case Q_DEFAULT:
3870 b0 = gen_hostop(cstate, addr, mask, Q_SRC, proto, src_off, dst_off);
3871 b1 = gen_hostop(cstate, addr, mask, Q_DST, proto, src_off, dst_off);
3872 gen_or(b0, b1);
3873 return b1;
3874
3875 case Q_ADDR1:
3876 bpf_error(cstate, "'addr1' and 'address1' are not valid qualifiers for addresses other than 802.11 MAC addresses");
3877 break;
3878
3879 case Q_ADDR2:
3880 bpf_error(cstate, "'addr2' and 'address2' are not valid qualifiers for addresses other than 802.11 MAC addresses");
3881 break;
3882
3883 case Q_ADDR3:
3884 bpf_error(cstate, "'addr3' and 'address3' are not valid qualifiers for addresses other than 802.11 MAC addresses");
3885 break;
3886
3887 case Q_ADDR4:
3888 bpf_error(cstate, "'addr4' and 'address4' are not valid qualifiers for addresses other than 802.11 MAC addresses");
3889 break;
3890
3891 case Q_RA:
3892 bpf_error(cstate, "'ra' is not a valid qualifier for addresses other than 802.11 MAC addresses");
3893 break;
3894
3895 case Q_TA:
3896 bpf_error(cstate, "'ta' is not a valid qualifier for addresses other than 802.11 MAC addresses");
3897 break;
3898
3899 default:
3900 abort();
3901 }
3902 b0 = gen_linktype(cstate, proto);
3903 b1 = gen_mcmp(cstate, OR_LINKPL, offset, BPF_W, (bpf_int32)addr, mask);
3904 gen_and(b0, b1);
3905 return b1;
3906}
3907
3908#ifdef INET6
3909static struct block *
3910gen_hostop6(compiler_state_t *cstate, struct in6_addr *addr,
3911 struct in6_addr *mask, int dir, int proto, u_int src_off, u_int dst_off)
3912{
3913 struct block *b0, *b1;
3914 u_int offset;
3915 uint32_t *a, *m;
3916
3917 switch (dir) {
3918
3919 case Q_SRC:
3920 offset = src_off;
3921 break;
3922
3923 case Q_DST:
3924 offset = dst_off;
3925 break;
3926
3927 case Q_AND:
3928 b0 = gen_hostop6(cstate, addr, mask, Q_SRC, proto, src_off, dst_off);
3929 b1 = gen_hostop6(cstate, addr, mask, Q_DST, proto, src_off, dst_off);
3930 gen_and(b0, b1);
3931 return b1;
3932
3933 case Q_OR:
3934 case Q_DEFAULT:
3935 b0 = gen_hostop6(cstate, addr, mask, Q_SRC, proto, src_off, dst_off);
3936 b1 = gen_hostop6(cstate, addr, mask, Q_DST, proto, src_off, dst_off);
3937 gen_or(b0, b1);
3938 return b1;
3939
3940 case Q_ADDR1:
3941 bpf_error(cstate, "'addr1' and 'address1' are not valid qualifiers for addresses other than 802.11 MAC addresses");
3942 break;
3943
3944 case Q_ADDR2:
3945 bpf_error(cstate, "'addr2' and 'address2' are not valid qualifiers for addresses other than 802.11 MAC addresses");
3946 break;
3947
3948 case Q_ADDR3:
3949 bpf_error(cstate, "'addr3' and 'address3' are not valid qualifiers for addresses other than 802.11 MAC addresses");
3950 break;
3951
3952 case Q_ADDR4:
3953 bpf_error(cstate, "'addr4' and 'address4' are not valid qualifiers for addresses other than 802.11 MAC addresses");
3954 break;
3955
3956 case Q_RA:
3957 bpf_error(cstate, "'ra' is not a valid qualifier for addresses other than 802.11 MAC addresses");
3958 break;
3959
3960 case Q_TA:
3961 bpf_error(cstate, "'ta' is not a valid qualifier for addresses other than 802.11 MAC addresses");
3962 break;
3963
3964 default:
3965 abort();
3966 }
3967 /* this order is important */
3968 a = (uint32_t *)addr;
3969 m = (uint32_t *)mask;
3970 b1 = gen_mcmp(cstate, OR_LINKPL, offset + 12, BPF_W, ntohl(a[3]), ntohl(m[3]));
3971 b0 = gen_mcmp(cstate, OR_LINKPL, offset + 8, BPF_W, ntohl(a[2]), ntohl(m[2]));
3972 gen_and(b0, b1);
3973 b0 = gen_mcmp(cstate, OR_LINKPL, offset + 4, BPF_W, ntohl(a[1]), ntohl(m[1]));
3974 gen_and(b0, b1);
3975 b0 = gen_mcmp(cstate, OR_LINKPL, offset + 0, BPF_W, ntohl(a[0]), ntohl(m[0]));
3976 gen_and(b0, b1);
3977 b0 = gen_linktype(cstate, proto);
3978 gen_and(b0, b1);
3979 return b1;
3980}
3981#endif
3982
3983static struct block *
3984gen_ehostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
3985{
3986 register struct block *b0, *b1;
3987
3988 switch (dir) {
3989 case Q_SRC:
3990 return gen_bcmp(cstate, OR_LINKHDR, 6, 6, eaddr);
3991
3992 case Q_DST:
3993 return gen_bcmp(cstate, OR_LINKHDR, 0, 6, eaddr);
3994
3995 case Q_AND:
3996 b0 = gen_ehostop(cstate, eaddr, Q_SRC);
3997 b1 = gen_ehostop(cstate, eaddr, Q_DST);
3998 gen_and(b0, b1);
3999 return b1;
4000
4001 case Q_DEFAULT:
4002 case Q_OR:
4003 b0 = gen_ehostop(cstate, eaddr, Q_SRC);
4004 b1 = gen_ehostop(cstate, eaddr, Q_DST);
4005 gen_or(b0, b1);
4006 return b1;
4007
4008 case Q_ADDR1:
4009 bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11 with 802.11 headers");
4010 break;
4011
4012 case Q_ADDR2:
4013 bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11 with 802.11 headers");
4014 break;
4015
4016 case Q_ADDR3:
4017 bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11 with 802.11 headers");
4018 break;
4019
4020 case Q_ADDR4:
4021 bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11 with 802.11 headers");
4022 break;
4023
4024 case Q_RA:
4025 bpf_error(cstate, "'ra' is only supported on 802.11 with 802.11 headers");
4026 break;
4027
4028 case Q_TA:
4029 bpf_error(cstate, "'ta' is only supported on 802.11 with 802.11 headers");
4030 break;
4031 }
4032 abort();
4033 /* NOTREACHED */
4034}
4035
4036/*
4037 * Like gen_ehostop, but for DLT_FDDI
4038 */
4039static struct block *
4040gen_fhostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
4041{
4042 struct block *b0, *b1;
4043
4044 switch (dir) {
4045 case Q_SRC:
4046 return gen_bcmp(cstate, OR_LINKHDR, 6 + 1 + cstate->pcap_fddipad, 6, eaddr);
4047
4048 case Q_DST:
4049 return gen_bcmp(cstate, OR_LINKHDR, 0 + 1 + cstate->pcap_fddipad, 6, eaddr);
4050
4051 case Q_AND:
4052 b0 = gen_fhostop(cstate, eaddr, Q_SRC);
4053 b1 = gen_fhostop(cstate, eaddr, Q_DST);
4054 gen_and(b0, b1);
4055 return b1;
4056
4057 case Q_DEFAULT:
4058 case Q_OR:
4059 b0 = gen_fhostop(cstate, eaddr, Q_SRC);
4060 b1 = gen_fhostop(cstate, eaddr, Q_DST);
4061 gen_or(b0, b1);
4062 return b1;
4063
4064 case Q_ADDR1:
4065 bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11");
4066 break;
4067
4068 case Q_ADDR2:
4069 bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11");
4070 break;
4071
4072 case Q_ADDR3:
4073 bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11");
4074 break;
4075
4076 case Q_ADDR4:
4077 bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11");
4078 break;
4079
4080 case Q_RA:
4081 bpf_error(cstate, "'ra' is only supported on 802.11");
4082 break;
4083
4084 case Q_TA:
4085 bpf_error(cstate, "'ta' is only supported on 802.11");
4086 break;
4087 }
4088 abort();
4089 /* NOTREACHED */
4090}
4091
4092/*
4093 * Like gen_ehostop, but for DLT_IEEE802 (Token Ring)
4094 */
4095static struct block *
4096gen_thostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
4097{
4098 register struct block *b0, *b1;
4099
4100 switch (dir) {
4101 case Q_SRC:
4102 return gen_bcmp(cstate, OR_LINKHDR, 8, 6, eaddr);
4103
4104 case Q_DST:
4105 return gen_bcmp(cstate, OR_LINKHDR, 2, 6, eaddr);
4106
4107 case Q_AND:
4108 b0 = gen_thostop(cstate, eaddr, Q_SRC);
4109 b1 = gen_thostop(cstate, eaddr, Q_DST);
4110 gen_and(b0, b1);
4111 return b1;
4112
4113 case Q_DEFAULT:
4114 case Q_OR:
4115 b0 = gen_thostop(cstate, eaddr, Q_SRC);
4116 b1 = gen_thostop(cstate, eaddr, Q_DST);
4117 gen_or(b0, b1);
4118 return b1;
4119
4120 case Q_ADDR1:
4121 bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11");
4122 break;
4123
4124 case Q_ADDR2:
4125 bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11");
4126 break;
4127
4128 case Q_ADDR3:
4129 bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11");
4130 break;
4131
4132 case Q_ADDR4:
4133 bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11");
4134 break;
4135
4136 case Q_RA:
4137 bpf_error(cstate, "'ra' is only supported on 802.11");
4138 break;
4139
4140 case Q_TA:
4141 bpf_error(cstate, "'ta' is only supported on 802.11");
4142 break;
4143 }
4144 abort();
4145 /* NOTREACHED */
4146}
4147
4148/*
4149 * Like gen_ehostop, but for DLT_IEEE802_11 (802.11 wireless LAN) and
4150 * various 802.11 + radio headers.
4151 */
4152static struct block *
4153gen_wlanhostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
4154{
4155 register struct block *b0, *b1, *b2;
4156 register struct slist *s;
4157
4158#ifdef ENABLE_WLAN_FILTERING_PATCH
4159 /*
4160 * TODO GV 20070613
4161 * We need to disable the optimizer because the optimizer is buggy
4162 * and wipes out some LD instructions generated by the below
4163 * code to validate the Frame Control bits
4164 */
4165 cstate->no_optimize = 1;
4166#endif /* ENABLE_WLAN_FILTERING_PATCH */
4167
4168 switch (dir) {
4169 case Q_SRC:
4170 /*
4171 * Oh, yuk.
4172 *
4173 * For control frames, there is no SA.
4174 *
4175 * For management frames, SA is at an
4176 * offset of 10 from the beginning of
4177 * the packet.
4178 *
4179 * For data frames, SA is at an offset
4180 * of 10 from the beginning of the packet
4181 * if From DS is clear, at an offset of
4182 * 16 from the beginning of the packet
4183 * if From DS is set and To DS is clear,
4184 * and an offset of 24 from the beginning
4185 * of the packet if From DS is set and To DS
4186 * is set.
4187 */
4188
4189 /*
4190 * Generate the tests to be done for data frames
4191 * with From DS set.
4192 *
4193 * First, check for To DS set, i.e. check "link[1] & 0x01".
4194 */
4195 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4196 b1 = new_block(cstate, JMP(BPF_JSET));
4197 b1->s.k = 0x01; /* To DS */
4198 b1->stmts = s;
4199
4200 /*
4201 * If To DS is set, the SA is at 24.
4202 */
4203 b0 = gen_bcmp(cstate, OR_LINKHDR, 24, 6, eaddr);
4204 gen_and(b1, b0);
4205
4206 /*
4207 * Now, check for To DS not set, i.e. check
4208 * "!(link[1] & 0x01)".
4209 */
4210 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4211 b2 = new_block(cstate, JMP(BPF_JSET));
4212 b2->s.k = 0x01; /* To DS */
4213 b2->stmts = s;
4214 gen_not(b2);
4215
4216 /*
4217 * If To DS is not set, the SA is at 16.
4218 */
4219 b1 = gen_bcmp(cstate, OR_LINKHDR, 16, 6, eaddr);
4220 gen_and(b2, b1);
4221
4222 /*
4223 * Now OR together the last two checks. That gives
4224 * the complete set of checks for data frames with
4225 * From DS set.
4226 */
4227 gen_or(b1, b0);
4228
4229 /*
4230 * Now check for From DS being set, and AND that with
4231 * the ORed-together checks.
4232 */
4233 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4234 b1 = new_block(cstate, JMP(BPF_JSET));
4235 b1->s.k = 0x02; /* From DS */
4236 b1->stmts = s;
4237 gen_and(b1, b0);
4238
4239 /*
4240 * Now check for data frames with From DS not set.
4241 */
4242 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4243 b2 = new_block(cstate, JMP(BPF_JSET));
4244 b2->s.k = 0x02; /* From DS */
4245 b2->stmts = s;
4246 gen_not(b2);
4247
4248 /*
4249 * If From DS isn't set, the SA is at 10.
4250 */
4251 b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
4252 gen_and(b2, b1);
4253
4254 /*
4255 * Now OR together the checks for data frames with
4256 * From DS not set and for data frames with From DS
4257 * set; that gives the checks done for data frames.
4258 */
4259 gen_or(b1, b0);
4260
4261 /*
4262 * Now check for a data frame.
4263 * I.e, check "link[0] & 0x08".
4264 */
4265 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4266 b1 = new_block(cstate, JMP(BPF_JSET));
4267 b1->s.k = 0x08;
4268 b1->stmts = s;
4269
4270 /*
4271 * AND that with the checks done for data frames.
4272 */
4273 gen_and(b1, b0);
4274
4275 /*
4276 * If the high-order bit of the type value is 0, this
4277 * is a management frame.
4278 * I.e, check "!(link[0] & 0x08)".
4279 */
4280 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4281 b2 = new_block(cstate, JMP(BPF_JSET));
4282 b2->s.k = 0x08;
4283 b2->stmts = s;
4284 gen_not(b2);
4285
4286 /*
4287 * For management frames, the SA is at 10.
4288 */
4289 b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
4290 gen_and(b2, b1);
4291
4292 /*
4293 * OR that with the checks done for data frames.
4294 * That gives the checks done for management and
4295 * data frames.
4296 */
4297 gen_or(b1, b0);
4298
4299 /*
4300 * If the low-order bit of the type value is 1,
4301 * this is either a control frame or a frame
4302 * with a reserved type, and thus not a
4303 * frame with an SA.
4304 *
4305 * I.e., check "!(link[0] & 0x04)".
4306 */
4307 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4308 b1 = new_block(cstate, JMP(BPF_JSET));
4309 b1->s.k = 0x04;
4310 b1->stmts = s;
4311 gen_not(b1);
4312
4313 /*
4314 * AND that with the checks for data and management
4315 * frames.
4316 */
4317 gen_and(b1, b0);
4318 return b0;
4319
4320 case Q_DST:
4321 /*
4322 * Oh, yuk.
4323 *
4324 * For control frames, there is no DA.
4325 *
4326 * For management frames, DA is at an
4327 * offset of 4 from the beginning of
4328 * the packet.
4329 *
4330 * For data frames, DA is at an offset
4331 * of 4 from the beginning of the packet
4332 * if To DS is clear and at an offset of
4333 * 16 from the beginning of the packet
4334 * if To DS is set.
4335 */
4336
4337 /*
4338 * Generate the tests to be done for data frames.
4339 *
4340 * First, check for To DS set, i.e. "link[1] & 0x01".
4341 */
4342 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4343 b1 = new_block(cstate, JMP(BPF_JSET));
4344 b1->s.k = 0x01; /* To DS */
4345 b1->stmts = s;
4346
4347 /*
4348 * If To DS is set, the DA is at 16.
4349 */
4350 b0 = gen_bcmp(cstate, OR_LINKHDR, 16, 6, eaddr);
4351 gen_and(b1, b0);
4352
4353 /*
4354 * Now, check for To DS not set, i.e. check
4355 * "!(link[1] & 0x01)".
4356 */
4357 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4358 b2 = new_block(cstate, JMP(BPF_JSET));
4359 b2->s.k = 0x01; /* To DS */
4360 b2->stmts = s;
4361 gen_not(b2);
4362
4363 /*
4364 * If To DS is not set, the DA is at 4.
4365 */
4366 b1 = gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr);
4367 gen_and(b2, b1);
4368
4369 /*
4370 * Now OR together the last two checks. That gives
4371 * the complete set of checks for data frames.
4372 */
4373 gen_or(b1, b0);
4374
4375 /*
4376 * Now check for a data frame.
4377 * I.e, check "link[0] & 0x08".
4378 */
4379 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4380 b1 = new_block(cstate, JMP(BPF_JSET));
4381 b1->s.k = 0x08;
4382 b1->stmts = s;
4383
4384 /*
4385 * AND that with the checks done for data frames.
4386 */
4387 gen_and(b1, b0);
4388
4389 /*
4390 * If the high-order bit of the type value is 0, this
4391 * is a management frame.
4392 * I.e, check "!(link[0] & 0x08)".
4393 */
4394 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4395 b2 = new_block(cstate, JMP(BPF_JSET));
4396 b2->s.k = 0x08;
4397 b2->stmts = s;
4398 gen_not(b2);
4399
4400 /*
4401 * For management frames, the DA is at 4.
4402 */
4403 b1 = gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr);
4404 gen_and(b2, b1);
4405
4406 /*
4407 * OR that with the checks done for data frames.
4408 * That gives the checks done for management and
4409 * data frames.
4410 */
4411 gen_or(b1, b0);
4412
4413 /*
4414 * If the low-order bit of the type value is 1,
4415 * this is either a control frame or a frame
4416 * with a reserved type, and thus not a
4417 * frame with an SA.
4418 *
4419 * I.e., check "!(link[0] & 0x04)".
4420 */
4421 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4422 b1 = new_block(cstate, JMP(BPF_JSET));
4423 b1->s.k = 0x04;
4424 b1->stmts = s;
4425 gen_not(b1);
4426
4427 /*
4428 * AND that with the checks for data and management
4429 * frames.
4430 */
4431 gen_and(b1, b0);
4432 return b0;
4433
4434 case Q_RA:
4435 /*
4436 * Not present in management frames; addr1 in other
4437 * frames.
4438 */
4439
4440 /*
4441 * If the high-order bit of the type value is 0, this
4442 * is a management frame.
4443 * I.e, check "(link[0] & 0x08)".
4444 */
4445 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4446 b1 = new_block(cstate, JMP(BPF_JSET));
4447 b1->s.k = 0x08;
4448 b1->stmts = s;
4449
4450 /*
4451 * Check addr1.
4452 */
4453 b0 = gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr);
4454
4455 /*
4456 * AND that with the check of addr1.
4457 */
4458 gen_and(b1, b0);
4459 return (b0);
4460
4461 case Q_TA:
4462 /*
4463 * Not present in management frames; addr2, if present,
4464 * in other frames.
4465 */
4466
4467 /*
4468 * Not present in CTS or ACK control frames.
4469 */
4470 b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_TYPE_CTL,
4471 IEEE80211_FC0_TYPE_MASK);
4472 gen_not(b0);
4473 b1 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_CTS,
4474 IEEE80211_FC0_SUBTYPE_MASK);
4475 gen_not(b1);
4476 b2 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_ACK,
4477 IEEE80211_FC0_SUBTYPE_MASK);
4478 gen_not(b2);
4479 gen_and(b1, b2);
4480 gen_or(b0, b2);
4481
4482 /*
4483 * If the high-order bit of the type value is 0, this
4484 * is a management frame.
4485 * I.e, check "(link[0] & 0x08)".
4486 */
4487 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4488 b1 = new_block(cstate, JMP(BPF_JSET));
4489 b1->s.k = 0x08;
4490 b1->stmts = s;
4491
4492 /*
4493 * AND that with the check for frames other than
4494 * CTS and ACK frames.
4495 */
4496 gen_and(b1, b2);
4497
4498 /*
4499 * Check addr2.
4500 */
4501 b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
4502 gen_and(b2, b1);
4503 return b1;
4504
4505 /*
4506 * XXX - add BSSID keyword?
4507 */
4508 case Q_ADDR1:
4509 return (gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr));
4510
4511 case Q_ADDR2:
4512 /*
4513 * Not present in CTS or ACK control frames.
4514 */
4515 b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_TYPE_CTL,
4516 IEEE80211_FC0_TYPE_MASK);
4517 gen_not(b0);
4518 b1 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_CTS,
4519 IEEE80211_FC0_SUBTYPE_MASK);
4520 gen_not(b1);
4521 b2 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_ACK,
4522 IEEE80211_FC0_SUBTYPE_MASK);
4523 gen_not(b2);
4524 gen_and(b1, b2);
4525 gen_or(b0, b2);
4526 b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
4527 gen_and(b2, b1);
4528 return b1;
4529
4530 case Q_ADDR3:
4531 /*
4532 * Not present in control frames.
4533 */
4534 b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_TYPE_CTL,
4535 IEEE80211_FC0_TYPE_MASK);
4536 gen_not(b0);
4537 b1 = gen_bcmp(cstate, OR_LINKHDR, 16, 6, eaddr);
4538 gen_and(b0, b1);
4539 return b1;
4540
4541 case Q_ADDR4:
4542 /*
4543 * Present only if the direction mask has both "From DS"
4544 * and "To DS" set. Neither control frames nor management
4545 * frames should have both of those set, so we don't
4546 * check the frame type.
4547 */
4548 b0 = gen_mcmp(cstate, OR_LINKHDR, 1, BPF_B,
4549 IEEE80211_FC1_DIR_DSTODS, IEEE80211_FC1_DIR_MASK);
4550 b1 = gen_bcmp(cstate, OR_LINKHDR, 24, 6, eaddr);
4551 gen_and(b0, b1);
4552 return b1;
4553
4554 case Q_AND:
4555 b0 = gen_wlanhostop(cstate, eaddr, Q_SRC);
4556 b1 = gen_wlanhostop(cstate, eaddr, Q_DST);
4557 gen_and(b0, b1);
4558 return b1;
4559
4560 case Q_DEFAULT:
4561 case Q_OR:
4562 b0 = gen_wlanhostop(cstate, eaddr, Q_SRC);
4563 b1 = gen_wlanhostop(cstate, eaddr, Q_DST);
4564 gen_or(b0, b1);
4565 return b1;
4566 }
4567 abort();
4568 /* NOTREACHED */
4569}
4570
4571/*
4572 * Like gen_ehostop, but for RFC 2625 IP-over-Fibre-Channel.
4573 * (We assume that the addresses are IEEE 48-bit MAC addresses,
4574 * as the RFC states.)
4575 */
4576static struct block *
4577gen_ipfchostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
4578{
4579 register struct block *b0, *b1;
4580
4581 switch (dir) {
4582 case Q_SRC:
4583 return gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
4584
4585 case Q_DST:
4586 return gen_bcmp(cstate, OR_LINKHDR, 2, 6, eaddr);
4587
4588 case Q_AND:
4589 b0 = gen_ipfchostop(cstate, eaddr, Q_SRC);
4590 b1 = gen_ipfchostop(cstate, eaddr, Q_DST);
4591 gen_and(b0, b1);
4592 return b1;
4593
4594 case Q_DEFAULT:
4595 case Q_OR:
4596 b0 = gen_ipfchostop(cstate, eaddr, Q_SRC);
4597 b1 = gen_ipfchostop(cstate, eaddr, Q_DST);
4598 gen_or(b0, b1);
4599 return b1;
4600
4601 case Q_ADDR1:
4602 bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11");
4603 break;
4604
4605 case Q_ADDR2:
4606 bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11");
4607 break;
4608
4609 case Q_ADDR3:
4610 bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11");
4611 break;
4612
4613 case Q_ADDR4:
4614 bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11");
4615 break;
4616
4617 case Q_RA:
4618 bpf_error(cstate, "'ra' is only supported on 802.11");
4619 break;
4620
4621 case Q_TA:
4622 bpf_error(cstate, "'ta' is only supported on 802.11");
4623 break;
4624 }
4625 abort();
4626 /* NOTREACHED */
4627}
4628
4629/*
4630 * This is quite tricky because there may be pad bytes in front of the
4631 * DECNET header, and then there are two possible data packet formats that
4632 * carry both src and dst addresses, plus 5 packet types in a format that
4633 * carries only the src node, plus 2 types that use a different format and
4634 * also carry just the src node.
4635 *
4636 * Yuck.
4637 *
4638 * Instead of doing those all right, we just look for data packets with
4639 * 0 or 1 bytes of padding. If you want to look at other packets, that
4640 * will require a lot more hacking.
4641 *
4642 * To add support for filtering on DECNET "areas" (network numbers)
4643 * one would want to add a "mask" argument to this routine. That would
4644 * make the filter even more inefficient, although one could be clever
4645 * and not generate masking instructions if the mask is 0xFFFF.
4646 */
4647static struct block *
4648gen_dnhostop(compiler_state_t *cstate, bpf_u_int32 addr, int dir)
4649{
4650 struct block *b0, *b1, *b2, *tmp;
4651 u_int offset_lh; /* offset if long header is received */
4652 u_int offset_sh; /* offset if short header is received */
4653
4654 switch (dir) {
4655
4656 case Q_DST:
4657 offset_sh = 1; /* follows flags */
4658 offset_lh = 7; /* flgs,darea,dsubarea,HIORD */
4659 break;
4660
4661 case Q_SRC:
4662 offset_sh = 3; /* follows flags, dstnode */
4663 offset_lh = 15; /* flgs,darea,dsubarea,did,sarea,ssub,HIORD */
4664 break;
4665
4666 case Q_AND:
4667 /* Inefficient because we do our Calvinball dance twice */
4668 b0 = gen_dnhostop(cstate, addr, Q_SRC);
4669 b1 = gen_dnhostop(cstate, addr, Q_DST);
4670 gen_and(b0, b1);
4671 return b1;
4672
4673 case Q_OR:
4674 case Q_DEFAULT:
4675 /* Inefficient because we do our Calvinball dance twice */
4676 b0 = gen_dnhostop(cstate, addr, Q_SRC);
4677 b1 = gen_dnhostop(cstate, addr, Q_DST);
4678 gen_or(b0, b1);
4679 return b1;
4680
4681 case Q_ISO:
4682 bpf_error(cstate, "ISO host filtering not implemented");
4683
4684 default:
4685 abort();
4686 }
4687 b0 = gen_linktype(cstate, ETHERTYPE_DN);
4688 /* Check for pad = 1, long header case */
4689 tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_H,
4690 (bpf_int32)ntohs(0x0681), (bpf_int32)ntohs(0x07FF));
4691 b1 = gen_cmp(cstate, OR_LINKPL, 2 + 1 + offset_lh,
4692 BPF_H, (bpf_int32)ntohs((u_short)addr));
4693 gen_and(tmp, b1);
4694 /* Check for pad = 0, long header case */
4695 tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_B, (bpf_int32)0x06, (bpf_int32)0x7);
4696 b2 = gen_cmp(cstate, OR_LINKPL, 2 + offset_lh, BPF_H, (bpf_int32)ntohs((u_short)addr));
4697 gen_and(tmp, b2);
4698 gen_or(b2, b1);
4699 /* Check for pad = 1, short header case */
4700 tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_H,
4701 (bpf_int32)ntohs(0x0281), (bpf_int32)ntohs(0x07FF));
4702 b2 = gen_cmp(cstate, OR_LINKPL, 2 + 1 + offset_sh, BPF_H, (bpf_int32)ntohs((u_short)addr));
4703 gen_and(tmp, b2);
4704 gen_or(b2, b1);
4705 /* Check for pad = 0, short header case */
4706 tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_B, (bpf_int32)0x02, (bpf_int32)0x7);
4707 b2 = gen_cmp(cstate, OR_LINKPL, 2 + offset_sh, BPF_H, (bpf_int32)ntohs((u_short)addr));
4708 gen_and(tmp, b2);
4709 gen_or(b2, b1);
4710
4711 /* Combine with test for cstate->linktype */
4712 gen_and(b0, b1);
4713 return b1;
4714}
4715
4716/*
4717 * Generate a check for IPv4 or IPv6 for MPLS-encapsulated packets;
4718 * test the bottom-of-stack bit, and then check the version number
4719 * field in the IP header.
4720 */
4721static struct block *
4722gen_mpls_linktype(compiler_state_t *cstate, int proto)
4723{
4724 struct block *b0, *b1;
4725
4726 switch (proto) {
4727
4728 case Q_IP:
4729 /* match the bottom-of-stack bit */
4730 b0 = gen_mcmp(cstate, OR_LINKPL, (u_int)-2, BPF_B, 0x01, 0x01);
4731 /* match the IPv4 version number */
4732 b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_B, 0x40, 0xf0);
4733 gen_and(b0, b1);
4734 return b1;
4735
4736 case Q_IPV6:
4737 /* match the bottom-of-stack bit */
4738 b0 = gen_mcmp(cstate, OR_LINKPL, (u_int)-2, BPF_B, 0x01, 0x01);
4739 /* match the IPv4 version number */
4740 b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_B, 0x60, 0xf0);
4741 gen_and(b0, b1);
4742 return b1;
4743
4744 default:
4745 abort();
4746 }
4747}
4748
4749static struct block *
4750gen_host(compiler_state_t *cstate, bpf_u_int32 addr, bpf_u_int32 mask,
4751 int proto, int dir, int type)
4752{
4753 struct block *b0, *b1;
4754 const char *typestr;
4755
4756 if (type == Q_NET)
4757 typestr = "net";
4758 else
4759 typestr = "host";
4760
4761 switch (proto) {
4762
4763 case Q_DEFAULT:
4764 b0 = gen_host(cstate, addr, mask, Q_IP, dir, type);
4765 /*
4766 * Only check for non-IPv4 addresses if we're not
4767 * checking MPLS-encapsulated packets.
4768 */
4769 if (cstate->label_stack_depth == 0) {
4770 b1 = gen_host(cstate, addr, mask, Q_ARP, dir, type);
4771 gen_or(b0, b1);
4772 b0 = gen_host(cstate, addr, mask, Q_RARP, dir, type);
4773 gen_or(b1, b0);
4774 }
4775 return b0;
4776
4777 case Q_IP:
4778 return gen_hostop(cstate, addr, mask, dir, ETHERTYPE_IP, 12, 16);
4779
4780 case Q_RARP:
4781 return gen_hostop(cstate, addr, mask, dir, ETHERTYPE_REVARP, 14, 24);
4782
4783 case Q_ARP:
4784 return gen_hostop(cstate, addr, mask, dir, ETHERTYPE_ARP, 14, 24);
4785
4786 case Q_TCP:
4787 bpf_error(cstate, "'tcp' modifier applied to %s", typestr);
4788
4789 case Q_SCTP:
4790 bpf_error(cstate, "'sctp' modifier applied to %s", typestr);
4791
4792 case Q_UDP:
4793 bpf_error(cstate, "'udp' modifier applied to %s", typestr);
4794
4795 case Q_ICMP:
4796 bpf_error(cstate, "'icmp' modifier applied to %s", typestr);
4797
4798 case Q_IGMP:
4799 bpf_error(cstate, "'igmp' modifier applied to %s", typestr);
4800
4801 case Q_IGRP:
4802 bpf_error(cstate, "'igrp' modifier applied to %s", typestr);
4803
4804 case Q_PIM:
4805 bpf_error(cstate, "'pim' modifier applied to %s", typestr);
4806
4807 case Q_VRRP:
4808 bpf_error(cstate, "'vrrp' modifier applied to %s", typestr);
4809
4810 case Q_CARP:
4811 bpf_error(cstate, "'carp' modifier applied to %s", typestr);
4812
4813 case Q_ATALK:
4814 bpf_error(cstate, "ATALK host filtering not implemented");
4815
4816 case Q_AARP:
4817 bpf_error(cstate, "AARP host filtering not implemented");
4818
4819 case Q_DECNET:
4820 return gen_dnhostop(cstate, addr, dir);
4821
4822 case Q_SCA:
4823 bpf_error(cstate, "SCA host filtering not implemented");
4824
4825 case Q_LAT:
4826 bpf_error(cstate, "LAT host filtering not implemented");
4827
4828 case Q_MOPDL:
4829 bpf_error(cstate, "MOPDL host filtering not implemented");
4830
4831 case Q_MOPRC:
4832 bpf_error(cstate, "MOPRC host filtering not implemented");
4833
4834 case Q_IPV6:
4835 bpf_error(cstate, "'ip6' modifier applied to ip host");
4836
4837 case Q_ICMPV6:
4838 bpf_error(cstate, "'icmp6' modifier applied to %s", typestr);
4839
4840 case Q_AH:
4841 bpf_error(cstate, "'ah' modifier applied to %s", typestr);
4842
4843 case Q_ESP:
4844 bpf_error(cstate, "'esp' modifier applied to %s", typestr);
4845
4846 case Q_ISO:
4847 bpf_error(cstate, "ISO host filtering not implemented");
4848
4849 case Q_ESIS:
4850 bpf_error(cstate, "'esis' modifier applied to %s", typestr);
4851
4852 case Q_ISIS:
4853 bpf_error(cstate, "'isis' modifier applied to %s", typestr);
4854
4855 case Q_CLNP:
4856 bpf_error(cstate, "'clnp' modifier applied to %s", typestr);
4857
4858 case Q_STP:
4859 bpf_error(cstate, "'stp' modifier applied to %s", typestr);
4860
4861 case Q_IPX:
4862 bpf_error(cstate, "IPX host filtering not implemented");
4863
4864 case Q_NETBEUI:
4865 bpf_error(cstate, "'netbeui' modifier applied to %s", typestr);
4866
4867 case Q_RADIO:
4868 bpf_error(cstate, "'radio' modifier applied to %s", typestr);
4869
4870 default:
4871 abort();
4872 }
4873 /* NOTREACHED */
4874}
4875
4876#ifdef INET6
4877static struct block *
4878gen_host6(compiler_state_t *cstate, struct in6_addr *addr,
4879 struct in6_addr *mask, int proto, int dir, int type)
4880{
4881 const char *typestr;
4882
4883 if (type == Q_NET)
4884 typestr = "net";
4885 else
4886 typestr = "host";
4887
4888 switch (proto) {
4889
4890 case Q_DEFAULT:
4891 return gen_host6(cstate, addr, mask, Q_IPV6, dir, type);
4892
4893 case Q_LINK:
4894 bpf_error(cstate, "link-layer modifier applied to ip6 %s", typestr);
4895
4896 case Q_IP:
4897 bpf_error(cstate, "'ip' modifier applied to ip6 %s", typestr);
4898
4899 case Q_RARP:
4900 bpf_error(cstate, "'rarp' modifier applied to ip6 %s", typestr);
4901
4902 case Q_ARP:
4903 bpf_error(cstate, "'arp' modifier applied to ip6 %s", typestr);
4904
4905 case Q_SCTP:
4906 bpf_error(cstate, "'sctp' modifier applied to %s", typestr);
4907
4908 case Q_TCP:
4909 bpf_error(cstate, "'tcp' modifier applied to %s", typestr);
4910
4911 case Q_UDP:
4912 bpf_error(cstate, "'udp' modifier applied to %s", typestr);
4913
4914 case Q_ICMP:
4915 bpf_error(cstate, "'icmp' modifier applied to %s", typestr);
4916
4917 case Q_IGMP:
4918 bpf_error(cstate, "'igmp' modifier applied to %s", typestr);
4919
4920 case Q_IGRP:
4921 bpf_error(cstate, "'igrp' modifier applied to %s", typestr);
4922
4923 case Q_PIM:
4924 bpf_error(cstate, "'pim' modifier applied to %s", typestr);
4925
4926 case Q_VRRP:
4927 bpf_error(cstate, "'vrrp' modifier applied to %s", typestr);
4928
4929 case Q_CARP:
4930 bpf_error(cstate, "'carp' modifier applied to %s", typestr);
4931
4932 case Q_ATALK:
4933 bpf_error(cstate, "ATALK host filtering not implemented");
4934
4935 case Q_AARP:
4936 bpf_error(cstate, "AARP host filtering not implemented");
4937
4938 case Q_DECNET:
4939 bpf_error(cstate, "'decnet' modifier applied to ip6 %s", typestr);
4940
4941 case Q_SCA:
4942 bpf_error(cstate, "SCA host filtering not implemented");
4943
4944 case Q_LAT:
4945 bpf_error(cstate, "LAT host filtering not implemented");
4946
4947 case Q_MOPDL:
4948 bpf_error(cstate, "MOPDL host filtering not implemented");
4949
4950 case Q_MOPRC:
4951 bpf_error(cstate, "MOPRC host filtering not implemented");
4952
4953 case Q_IPV6:
4954 return gen_hostop6(cstate, addr, mask, dir, ETHERTYPE_IPV6, 8, 24);
4955
4956 case Q_ICMPV6:
4957 bpf_error(cstate, "'icmp6' modifier applied to %s", typestr);
4958
4959 case Q_AH:
4960 bpf_error(cstate, "'ah' modifier applied to %s", typestr);
4961
4962 case Q_ESP:
4963 bpf_error(cstate, "'esp' modifier applied to %s", typestr);
4964
4965 case Q_ISO:
4966 bpf_error(cstate, "ISO host filtering not implemented");
4967
4968 case Q_ESIS:
4969 bpf_error(cstate, "'esis' modifier applied to %s", typestr);
4970
4971 case Q_ISIS:
4972 bpf_error(cstate, "'isis' modifier applied to %s", typestr);
4973
4974 case Q_CLNP:
4975 bpf_error(cstate, "'clnp' modifier applied to %s", typestr);
4976
4977 case Q_STP:
4978 bpf_error(cstate, "'stp' modifier applied to %s", typestr);
4979
4980 case Q_IPX:
4981 bpf_error(cstate, "IPX host filtering not implemented");
4982
4983 case Q_NETBEUI:
4984 bpf_error(cstate, "'netbeui' modifier applied to %s", typestr);
4985
4986 case Q_RADIO:
4987 bpf_error(cstate, "'radio' modifier applied to %s", typestr);
4988
4989 default:
4990 abort();
4991 }
4992 /* NOTREACHED */
4993}
4994#endif
4995
4996#ifndef INET6
4997static struct block *
4998gen_gateway(compiler_state_t *cstate, const u_char *eaddr,
4999 struct addrinfo *alist, int proto, int dir)
5000{
5001 struct block *b0, *b1, *tmp;
5002 struct addrinfo *ai;
5003 struct sockaddr_in *sin;
5004
5005 if (dir != 0)
5006 bpf_error(cstate, "direction applied to 'gateway'");
5007
5008 switch (proto) {
5009 case Q_DEFAULT:
5010 case Q_IP:
5011 case Q_ARP:
5012 case Q_RARP:
5013 switch (cstate->linktype) {
5014 case DLT_EN10MB:
5015 case DLT_NETANALYZER:
5016 case DLT_NETANALYZER_TRANSPARENT:
5017 b1 = gen_prevlinkhdr_check(cstate);
5018 b0 = gen_ehostop(cstate, eaddr, Q_OR);
5019 if (b1 != NULL)
5020 gen_and(b1, b0);
5021 break;
5022 case DLT_FDDI:
5023 b0 = gen_fhostop(cstate, eaddr, Q_OR);
5024 break;
5025 case DLT_IEEE802:
5026 b0 = gen_thostop(cstate, eaddr, Q_OR);
5027 break;
5028 case DLT_IEEE802_11:
5029 case DLT_PRISM_HEADER:
5030 case DLT_IEEE802_11_RADIO_AVS:
5031 case DLT_IEEE802_11_RADIO:
5032 case DLT_PPI:
5033 b0 = gen_wlanhostop(cstate, eaddr, Q_OR);
5034 break;
5035 case DLT_SUNATM:
5036 /*
5037 * This is LLC-multiplexed traffic; if it were
5038 * LANE, cstate->linktype would have been set to
5039 * DLT_EN10MB.
5040 */
5041 bpf_error(cstate,
5042 "'gateway' supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
5043 break;
5044 case DLT_IP_OVER_FC:
5045 b0 = gen_ipfchostop(cstate, eaddr, Q_OR);
5046 break;
5047 default:
5048 bpf_error(cstate,
5049 "'gateway' supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
5050 }
5051 b1 = NULL;
5052 for (ai = alist; ai != NULL; ai = ai->ai_next) {
5053 /*
5054 * Does it have an address?
5055 */
5056 if (ai->ai_addr != NULL) {
5057 /*
5058 * Yes. Is it an IPv4 address?
5059 */
5060 if (ai->ai_addr->sa_family == AF_INET) {
5061 /*
5062 * Generate an entry for it.
5063 */
5064 sin = (struct sockaddr_in *)ai->ai_addr;
5065 tmp = gen_host(cstate,
5066 ntohl(sin->sin_addr.s_addr),
5067 0xffffffff, proto, Q_OR, Q_HOST);
5068 /*
5069 * Is it the *first* IPv4 address?
5070 */
5071 if (b1 == NULL) {
5072 /*
5073 * Yes, so start with it.
5074 */
5075 b1 = tmp;
5076 } else {
5077 /*
5078 * No, so OR it into the
5079 * existing set of
5080 * addresses.
5081 */
5082 gen_or(b1, tmp);
5083 b1 = tmp;
5084 }
5085 }
5086 }
5087 }
5088 if (b1 == NULL) {
5089 /*
5090 * No IPv4 addresses found.
5091 */
5092 return (NULL);
5093 }
5094 gen_not(b1);
5095 gen_and(b0, b1);
5096 return b1;
5097 }
5098 bpf_error(cstate, "illegal modifier of 'gateway'");
5099 /* NOTREACHED */
5100}
5101#endif
5102
5103struct block *
5104gen_proto_abbrev(compiler_state_t *cstate, int proto)
5105{
5106 struct block *b0;
5107 struct block *b1;
5108
5109 switch (proto) {
5110
5111 case Q_SCTP:
5112 b1 = gen_proto(cstate, IPPROTO_SCTP, Q_IP, Q_DEFAULT);
5113 b0 = gen_proto(cstate, IPPROTO_SCTP, Q_IPV6, Q_DEFAULT);
5114 gen_or(b0, b1);
5115 break;
5116
5117 case Q_TCP:
5118 b1 = gen_proto(cstate, IPPROTO_TCP, Q_IP, Q_DEFAULT);
5119 b0 = gen_proto(cstate, IPPROTO_TCP, Q_IPV6, Q_DEFAULT);
5120 gen_or(b0, b1);
5121 break;
5122
5123 case Q_UDP:
5124 b1 = gen_proto(cstate, IPPROTO_UDP, Q_IP, Q_DEFAULT);
5125 b0 = gen_proto(cstate, IPPROTO_UDP, Q_IPV6, Q_DEFAULT);
5126 gen_or(b0, b1);
5127 break;
5128
5129 case Q_ICMP:
5130 b1 = gen_proto(cstate, IPPROTO_ICMP, Q_IP, Q_DEFAULT);
5131 break;
5132
5133#ifndef IPPROTO_IGMP
5134#define IPPROTO_IGMP 2
5135#endif
5136
5137 case Q_IGMP:
5138 b1 = gen_proto(cstate, IPPROTO_IGMP, Q_IP, Q_DEFAULT);
5139 break;
5140
5141#ifndef IPPROTO_IGRP
5142#define IPPROTO_IGRP 9
5143#endif
5144 case Q_IGRP:
5145 b1 = gen_proto(cstate, IPPROTO_IGRP, Q_IP, Q_DEFAULT);
5146 break;
5147
5148#ifndef IPPROTO_PIM
5149#define IPPROTO_PIM 103
5150#endif
5151
5152 case Q_PIM:
5153 b1 = gen_proto(cstate, IPPROTO_PIM, Q_IP, Q_DEFAULT);
5154 b0 = gen_proto(cstate, IPPROTO_PIM, Q_IPV6, Q_DEFAULT);
5155 gen_or(b0, b1);
5156 break;
5157
5158#ifndef IPPROTO_VRRP
5159#define IPPROTO_VRRP 112
5160#endif
5161
5162 case Q_VRRP:
5163 b1 = gen_proto(cstate, IPPROTO_VRRP, Q_IP, Q_DEFAULT);
5164 break;
5165
5166#ifndef IPPROTO_CARP
5167#define IPPROTO_CARP 112
5168#endif
5169
5170 case Q_CARP:
5171 b1 = gen_proto(cstate, IPPROTO_CARP, Q_IP, Q_DEFAULT);
5172 break;
5173
5174 case Q_IP:
5175 b1 = gen_linktype(cstate, ETHERTYPE_IP);
5176 break;
5177
5178 case Q_ARP:
5179 b1 = gen_linktype(cstate, ETHERTYPE_ARP);
5180 break;
5181
5182 case Q_RARP:
5183 b1 = gen_linktype(cstate, ETHERTYPE_REVARP);
5184 break;
5185
5186 case Q_LINK:
5187 bpf_error(cstate, "link layer applied in wrong context");
5188
5189 case Q_ATALK:
5190 b1 = gen_linktype(cstate, ETHERTYPE_ATALK);
5191 break;
5192
5193 case Q_AARP:
5194 b1 = gen_linktype(cstate, ETHERTYPE_AARP);
5195 break;
5196
5197 case Q_DECNET:
5198 b1 = gen_linktype(cstate, ETHERTYPE_DN);
5199 break;
5200
5201 case Q_SCA:
5202 b1 = gen_linktype(cstate, ETHERTYPE_SCA);
5203 break;
5204
5205 case Q_LAT:
5206 b1 = gen_linktype(cstate, ETHERTYPE_LAT);
5207 break;
5208
5209 case Q_MOPDL:
5210 b1 = gen_linktype(cstate, ETHERTYPE_MOPDL);
5211 break;
5212
5213 case Q_MOPRC:
5214 b1 = gen_linktype(cstate, ETHERTYPE_MOPRC);
5215 break;
5216
5217 case Q_IPV6:
5218 b1 = gen_linktype(cstate, ETHERTYPE_IPV6);
5219 break;
5220
5221#ifndef IPPROTO_ICMPV6
5222#define IPPROTO_ICMPV6 58
5223#endif
5224 case Q_ICMPV6:
5225 b1 = gen_proto(cstate, IPPROTO_ICMPV6, Q_IPV6, Q_DEFAULT);
5226 break;
5227
5228#ifndef IPPROTO_AH
5229#define IPPROTO_AH 51
5230#endif
5231 case Q_AH:
5232 b1 = gen_proto(cstate, IPPROTO_AH, Q_IP, Q_DEFAULT);
5233 b0 = gen_proto(cstate, IPPROTO_AH, Q_IPV6, Q_DEFAULT);
5234 gen_or(b0, b1);
5235 break;
5236
5237#ifndef IPPROTO_ESP
5238#define IPPROTO_ESP 50
5239#endif
5240 case Q_ESP:
5241 b1 = gen_proto(cstate, IPPROTO_ESP, Q_IP, Q_DEFAULT);
5242 b0 = gen_proto(cstate, IPPROTO_ESP, Q_IPV6, Q_DEFAULT);
5243 gen_or(b0, b1);
5244 break;
5245
5246 case Q_ISO:
5247 b1 = gen_linktype(cstate, LLCSAP_ISONS);
5248 break;
5249
5250 case Q_ESIS:
5251 b1 = gen_proto(cstate, ISO9542_ESIS, Q_ISO, Q_DEFAULT);
5252 break;
5253
5254 case Q_ISIS:
5255 b1 = gen_proto(cstate, ISO10589_ISIS, Q_ISO, Q_DEFAULT);
5256 break;
5257
5258 case Q_ISIS_L1: /* all IS-IS Level1 PDU-Types */
5259 b0 = gen_proto(cstate, ISIS_L1_LAN_IIH, Q_ISIS, Q_DEFAULT);
5260 b1 = gen_proto(cstate, ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); /* FIXME extract the circuit-type bits */
5261 gen_or(b0, b1);
5262 b0 = gen_proto(cstate, ISIS_L1_LSP, Q_ISIS, Q_DEFAULT);
5263 gen_or(b0, b1);
5264 b0 = gen_proto(cstate, ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
5265 gen_or(b0, b1);
5266 b0 = gen_proto(cstate, ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
5267 gen_or(b0, b1);
5268 break;
5269
5270 case Q_ISIS_L2: /* all IS-IS Level2 PDU-Types */
5271 b0 = gen_proto(cstate, ISIS_L2_LAN_IIH, Q_ISIS, Q_DEFAULT);
5272 b1 = gen_proto(cstate, ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); /* FIXME extract the circuit-type bits */
5273 gen_or(b0, b1);
5274 b0 = gen_proto(cstate, ISIS_L2_LSP, Q_ISIS, Q_DEFAULT);
5275 gen_or(b0, b1);
5276 b0 = gen_proto(cstate, ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
5277 gen_or(b0, b1);
5278 b0 = gen_proto(cstate, ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
5279 gen_or(b0, b1);
5280 break;
5281
5282 case Q_ISIS_IIH: /* all IS-IS Hello PDU-Types */
5283 b0 = gen_proto(cstate, ISIS_L1_LAN_IIH, Q_ISIS, Q_DEFAULT);
5284 b1 = gen_proto(cstate, ISIS_L2_LAN_IIH, Q_ISIS, Q_DEFAULT);
5285 gen_or(b0, b1);
5286 b0 = gen_proto(cstate, ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT);
5287 gen_or(b0, b1);
5288 break;
5289
5290 case Q_ISIS_LSP:
5291 b0 = gen_proto(cstate, ISIS_L1_LSP, Q_ISIS, Q_DEFAULT);
5292 b1 = gen_proto(cstate, ISIS_L2_LSP, Q_ISIS, Q_DEFAULT);
5293 gen_or(b0, b1);
5294 break;
5295
5296 case Q_ISIS_SNP:
5297 b0 = gen_proto(cstate, ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
5298 b1 = gen_proto(cstate, ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
5299 gen_or(b0, b1);
5300 b0 = gen_proto(cstate, ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
5301 gen_or(b0, b1);
5302 b0 = gen_proto(cstate, ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
5303 gen_or(b0, b1);
5304 break;
5305
5306 case Q_ISIS_CSNP:
5307 b0 = gen_proto(cstate, ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
5308 b1 = gen_proto(cstate, ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
5309 gen_or(b0, b1);
5310 break;
5311
5312 case Q_ISIS_PSNP:
5313 b0 = gen_proto(cstate, ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
5314 b1 = gen_proto(cstate, ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
5315 gen_or(b0, b1);
5316 break;
5317
5318 case Q_CLNP:
5319 b1 = gen_proto(cstate, ISO8473_CLNP, Q_ISO, Q_DEFAULT);
5320 break;
5321
5322 case Q_STP:
5323 b1 = gen_linktype(cstate, LLCSAP_8021D);
5324 break;
5325
5326 case Q_IPX:
5327 b1 = gen_linktype(cstate, LLCSAP_IPX);
5328 break;
5329
5330 case Q_NETBEUI:
5331 b1 = gen_linktype(cstate, LLCSAP_NETBEUI);
5332 break;
5333
5334 case Q_RADIO:
5335 bpf_error(cstate, "'radio' is not a valid protocol type");
5336
5337 default:
5338 abort();
5339 }
5340 return b1;
5341}
5342
5343static struct block *
5344gen_ipfrag(compiler_state_t *cstate)
5345{
5346 struct slist *s;
5347 struct block *b;
5348
5349 /* not IPv4 frag other than the first frag */
5350 s = gen_load_a(cstate, OR_LINKPL, 6, BPF_H);
5351 b = new_block(cstate, JMP(BPF_JSET));
5352 b->s.k = 0x1fff;
5353 b->stmts = s;
5354 gen_not(b);
5355
5356 return b;
5357}
5358
5359/*
5360 * Generate a comparison to a port value in the transport-layer header
5361 * at the specified offset from the beginning of that header.
5362 *
5363 * XXX - this handles a variable-length prefix preceding the link-layer
5364 * header, such as the radiotap or AVS radio prefix, but doesn't handle
5365 * variable-length link-layer headers (such as Token Ring or 802.11
5366 * headers).
5367 */
5368static struct block *
5369gen_portatom(compiler_state_t *cstate, int off, bpf_int32 v)
5370{
5371 return gen_cmp(cstate, OR_TRAN_IPV4, off, BPF_H, v);
5372}
5373
5374static struct block *
5375gen_portatom6(compiler_state_t *cstate, int off, bpf_int32 v)
5376{
5377 return gen_cmp(cstate, OR_TRAN_IPV6, off, BPF_H, v);
5378}
5379
5380struct block *
5381gen_portop(compiler_state_t *cstate, int port, int proto, int dir)
5382{
5383 struct block *b0, *b1, *tmp;
5384
5385 /* ip proto 'proto' and not a fragment other than the first fragment */
5386 tmp = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, (bpf_int32)proto);
5387 b0 = gen_ipfrag(cstate);
5388 gen_and(tmp, b0);
5389
5390 switch (dir) {
5391 case Q_SRC:
5392 b1 = gen_portatom(cstate, 0, (bpf_int32)port);
5393 break;
5394
5395 case Q_DST:
5396 b1 = gen_portatom(cstate, 2, (bpf_int32)port);
5397 break;
5398
5399 case Q_OR:
5400 case Q_DEFAULT:
5401 tmp = gen_portatom(cstate, 0, (bpf_int32)port);
5402 b1 = gen_portatom(cstate, 2, (bpf_int32)port);
5403 gen_or(tmp, b1);
5404 break;
5405
5406 case Q_AND:
5407 tmp = gen_portatom(cstate, 0, (bpf_int32)port);
5408 b1 = gen_portatom(cstate, 2, (bpf_int32)port);
5409 gen_and(tmp, b1);
5410 break;
5411
5412 default:
5413 abort();
5414 }
5415 gen_and(b0, b1);
5416
5417 return b1;
5418}
5419
5420static struct block *
5421gen_port(compiler_state_t *cstate, int port, int ip_proto, int dir)
5422{
5423 struct block *b0, *b1, *tmp;
5424
5425 /*
5426 * ether proto ip
5427 *
5428 * For FDDI, RFC 1188 says that SNAP encapsulation is used,
5429 * not LLC encapsulation with LLCSAP_IP.
5430 *
5431 * For IEEE 802 networks - which includes 802.5 token ring
5432 * (which is what DLT_IEEE802 means) and 802.11 - RFC 1042
5433 * says that SNAP encapsulation is used, not LLC encapsulation
5434 * with LLCSAP_IP.
5435 *
5436 * For LLC-encapsulated ATM/"Classical IP", RFC 1483 and
5437 * RFC 2225 say that SNAP encapsulation is used, not LLC
5438 * encapsulation with LLCSAP_IP.
5439 *
5440 * So we always check for ETHERTYPE_IP.
5441 */
5442 b0 = gen_linktype(cstate, ETHERTYPE_IP);
5443
5444 switch (ip_proto) {
5445 case IPPROTO_UDP:
5446 case IPPROTO_TCP:
5447 case IPPROTO_SCTP:
5448 b1 = gen_portop(cstate, port, ip_proto, dir);
5449 break;
5450
5451 case PROTO_UNDEF:
5452 tmp = gen_portop(cstate, port, IPPROTO_TCP, dir);
5453 b1 = gen_portop(cstate, port, IPPROTO_UDP, dir);
5454 gen_or(tmp, b1);
5455 tmp = gen_portop(cstate, port, IPPROTO_SCTP, dir);
5456 gen_or(tmp, b1);
5457 break;
5458
5459 default:
5460 abort();
5461 }
5462 gen_and(b0, b1);
5463 return b1;
5464}
5465
5466struct block *
5467gen_portop6(compiler_state_t *cstate, int port, int proto, int dir)
5468{
5469 struct block *b0, *b1, *tmp;
5470
5471 /* ip6 proto 'proto' */
5472 /* XXX - catch the first fragment of a fragmented packet? */
5473 b0 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, (bpf_int32)proto);
5474
5475 switch (dir) {
5476 case Q_SRC:
5477 b1 = gen_portatom6(cstate, 0, (bpf_int32)port);
5478 break;
5479
5480 case Q_DST:
5481 b1 = gen_portatom6(cstate, 2, (bpf_int32)port);
5482 break;
5483
5484 case Q_OR:
5485 case Q_DEFAULT:
5486 tmp = gen_portatom6(cstate, 0, (bpf_int32)port);
5487 b1 = gen_portatom6(cstate, 2, (bpf_int32)port);
5488 gen_or(tmp, b1);
5489 break;
5490
5491 case Q_AND:
5492 tmp = gen_portatom6(cstate, 0, (bpf_int32)port);
5493 b1 = gen_portatom6(cstate, 2, (bpf_int32)port);
5494 gen_and(tmp, b1);
5495 break;
5496
5497 default:
5498 abort();
5499 }
5500 gen_and(b0, b1);
5501
5502 return b1;
5503}
5504
5505static struct block *
5506gen_port6(compiler_state_t *cstate, int port, int ip_proto, int dir)
5507{
5508 struct block *b0, *b1, *tmp;
5509
5510 /* link proto ip6 */
5511 b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
5512
5513 switch (ip_proto) {
5514 case IPPROTO_UDP:
5515 case IPPROTO_TCP:
5516 case IPPROTO_SCTP:
5517 b1 = gen_portop6(cstate, port, ip_proto, dir);
5518 break;
5519
5520 case PROTO_UNDEF:
5521 tmp = gen_portop6(cstate, port, IPPROTO_TCP, dir);
5522 b1 = gen_portop6(cstate, port, IPPROTO_UDP, dir);
5523 gen_or(tmp, b1);
5524 tmp = gen_portop6(cstate, port, IPPROTO_SCTP, dir);
5525 gen_or(tmp, b1);
5526 break;
5527
5528 default:
5529 abort();
5530 }
5531 gen_and(b0, b1);
5532 return b1;
5533}
5534
5535/* gen_portrange code */
5536static struct block *
5537gen_portrangeatom(compiler_state_t *cstate, int off, bpf_int32 v1,
5538 bpf_int32 v2)
5539{
5540 struct block *b1, *b2;
5541
5542 if (v1 > v2) {
5543 /*
5544 * Reverse the order of the ports, so v1 is the lower one.
5545 */
5546 bpf_int32 vtemp;
5547
5548 vtemp = v1;
5549 v1 = v2;
5550 v2 = vtemp;
5551 }
5552
5553 b1 = gen_cmp_ge(cstate, OR_TRAN_IPV4, off, BPF_H, v1);
5554 b2 = gen_cmp_le(cstate, OR_TRAN_IPV4, off, BPF_H, v2);
5555
5556 gen_and(b1, b2);
5557
5558 return b2;
5559}
5560
5561struct block *
5562gen_portrangeop(compiler_state_t *cstate, int port1, int port2, int proto,
5563 int dir)
5564{
5565 struct block *b0, *b1, *tmp;
5566
5567 /* ip proto 'proto' and not a fragment other than the first fragment */
5568 tmp = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, (bpf_int32)proto);
5569 b0 = gen_ipfrag(cstate);
5570 gen_and(tmp, b0);
5571
5572 switch (dir) {
5573 case Q_SRC:
5574 b1 = gen_portrangeatom(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5575 break;
5576
5577 case Q_DST:
5578 b1 = gen_portrangeatom(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5579 break;
5580
5581 case Q_OR:
5582 case Q_DEFAULT:
5583 tmp = gen_portrangeatom(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5584 b1 = gen_portrangeatom(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5585 gen_or(tmp, b1);
5586 break;
5587
5588 case Q_AND:
5589 tmp = gen_portrangeatom(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5590 b1 = gen_portrangeatom(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5591 gen_and(tmp, b1);
5592 break;
5593
5594 default:
5595 abort();
5596 }
5597 gen_and(b0, b1);
5598
5599 return b1;
5600}
5601
5602static struct block *
5603gen_portrange(compiler_state_t *cstate, int port1, int port2, int ip_proto,
5604 int dir)
5605{
5606 struct block *b0, *b1, *tmp;
5607
5608 /* link proto ip */
5609 b0 = gen_linktype(cstate, ETHERTYPE_IP);
5610
5611 switch (ip_proto) {
5612 case IPPROTO_UDP:
5613 case IPPROTO_TCP:
5614 case IPPROTO_SCTP:
5615 b1 = gen_portrangeop(cstate, port1, port2, ip_proto, dir);
5616 break;
5617
5618 case PROTO_UNDEF:
5619 tmp = gen_portrangeop(cstate, port1, port2, IPPROTO_TCP, dir);
5620 b1 = gen_portrangeop(cstate, port1, port2, IPPROTO_UDP, dir);
5621 gen_or(tmp, b1);
5622 tmp = gen_portrangeop(cstate, port1, port2, IPPROTO_SCTP, dir);
5623 gen_or(tmp, b1);
5624 break;
5625
5626 default:
5627 abort();
5628 }
5629 gen_and(b0, b1);
5630 return b1;
5631}
5632
5633static struct block *
5634gen_portrangeatom6(compiler_state_t *cstate, int off, bpf_int32 v1,
5635 bpf_int32 v2)
5636{
5637 struct block *b1, *b2;
5638
5639 if (v1 > v2) {
5640 /*
5641 * Reverse the order of the ports, so v1 is the lower one.
5642 */
5643 bpf_int32 vtemp;
5644
5645 vtemp = v1;
5646 v1 = v2;
5647 v2 = vtemp;
5648 }
5649
5650 b1 = gen_cmp_ge(cstate, OR_TRAN_IPV6, off, BPF_H, v1);
5651 b2 = gen_cmp_le(cstate, OR_TRAN_IPV6, off, BPF_H, v2);
5652
5653 gen_and(b1, b2);
5654
5655 return b2;
5656}
5657
5658struct block *
5659gen_portrangeop6(compiler_state_t *cstate, int port1, int port2, int proto,
5660 int dir)
5661{
5662 struct block *b0, *b1, *tmp;
5663
5664 /* ip6 proto 'proto' */
5665 /* XXX - catch the first fragment of a fragmented packet? */
5666 b0 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, (bpf_int32)proto);
5667
5668 switch (dir) {
5669 case Q_SRC:
5670 b1 = gen_portrangeatom6(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5671 break;
5672
5673 case Q_DST:
5674 b1 = gen_portrangeatom6(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5675 break;
5676
5677 case Q_OR:
5678 case Q_DEFAULT:
5679 tmp = gen_portrangeatom6(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5680 b1 = gen_portrangeatom6(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5681 gen_or(tmp, b1);
5682 break;
5683
5684 case Q_AND:
5685 tmp = gen_portrangeatom6(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5686 b1 = gen_portrangeatom6(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5687 gen_and(tmp, b1);
5688 break;
5689
5690 default:
5691 abort();
5692 }
5693 gen_and(b0, b1);
5694
5695 return b1;
5696}
5697
5698static struct block *
5699gen_portrange6(compiler_state_t *cstate, int port1, int port2, int ip_proto,
5700 int dir)
5701{
5702 struct block *b0, *b1, *tmp;
5703
5704 /* link proto ip6 */
5705 b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
5706
5707 switch (ip_proto) {
5708 case IPPROTO_UDP:
5709 case IPPROTO_TCP:
5710 case IPPROTO_SCTP:
5711 b1 = gen_portrangeop6(cstate, port1, port2, ip_proto, dir);
5712 break;
5713
5714 case PROTO_UNDEF:
5715 tmp = gen_portrangeop6(cstate, port1, port2, IPPROTO_TCP, dir);
5716 b1 = gen_portrangeop6(cstate, port1, port2, IPPROTO_UDP, dir);
5717 gen_or(tmp, b1);
5718 tmp = gen_portrangeop6(cstate, port1, port2, IPPROTO_SCTP, dir);
5719 gen_or(tmp, b1);
5720 break;
5721
5722 default:
5723 abort();
5724 }
5725 gen_and(b0, b1);
5726 return b1;
5727}
5728
5729static int
5730lookup_proto(compiler_state_t *cstate, const char *name, int proto)
5731{
5732 register int v;
5733
5734 switch (proto) {
5735
5736 case Q_DEFAULT:
5737 case Q_IP:
5738 case Q_IPV6:
5739 v = pcap_nametoproto(name);
5740 if (v == PROTO_UNDEF)
5741 bpf_error(cstate, "unknown ip proto '%s'", name);
5742 break;
5743
5744 case Q_LINK:
5745 /* XXX should look up h/w protocol type based on cstate->linktype */
5746 v = pcap_nametoeproto(name);
5747 if (v == PROTO_UNDEF) {
5748 v = pcap_nametollc(name);
5749 if (v == PROTO_UNDEF)
5750 bpf_error(cstate, "unknown ether proto '%s'", name);
5751 }
5752 break;
5753
5754 case Q_ISO:
5755 if (strcmp(name, "esis") == 0)
5756 v = ISO9542_ESIS;
5757 else if (strcmp(name, "isis") == 0)
5758 v = ISO10589_ISIS;
5759 else if (strcmp(name, "clnp") == 0)
5760 v = ISO8473_CLNP;
5761 else
5762 bpf_error(cstate, "unknown osi proto '%s'", name);
5763 break;
5764
5765 default:
5766 v = PROTO_UNDEF;
5767 break;
5768 }
5769 return v;
5770}
5771
5772#if 0
5773struct stmt *
5774gen_joinsp(struct stmt **s, int n)
5775{
5776 return NULL;
5777}
5778#endif
5779
5780static struct block *
5781gen_protochain(compiler_state_t *cstate, int v, int proto, int dir)
5782{
5783#ifdef NO_PROTOCHAIN
5784 return gen_proto(cstate, v, proto, dir);
5785#else
5786 struct block *b0, *b;
5787 struct slist *s[100];
5788 int fix2, fix3, fix4, fix5;
5789 int ahcheck, again, end;
5790 int i, max;
5791 int reg2 = alloc_reg(cstate);
5792
5793 memset(s, 0, sizeof(s));
5794 fix3 = fix4 = fix5 = 0;
5795
5796 switch (proto) {
5797 case Q_IP:
5798 case Q_IPV6:
5799 break;
5800 case Q_DEFAULT:
5801 b0 = gen_protochain(cstate, v, Q_IP, dir);
5802 b = gen_protochain(cstate, v, Q_IPV6, dir);
5803 gen_or(b0, b);
5804 return b;
5805 default:
5806 bpf_error(cstate, "bad protocol applied for 'protochain'");
5807 /*NOTREACHED*/
5808 }
5809
5810 /*
5811 * We don't handle variable-length prefixes before the link-layer
5812 * header, or variable-length link-layer headers, here yet.
5813 * We might want to add BPF instructions to do the protochain
5814 * work, to simplify that and, on platforms that have a BPF
5815 * interpreter with the new instructions, let the filtering
5816 * be done in the kernel. (We already require a modified BPF
5817 * engine to do the protochain stuff, to support backward
5818 * branches, and backward branch support is unlikely to appear
5819 * in kernel BPF engines.)
5820 */
5821 if (cstate->off_linkpl.is_variable)
5822 bpf_error(cstate, "'protochain' not supported with variable length headers");
5823
5824 cstate->no_optimize = 1; /* this code is not compatible with optimizer yet */
5825
5826 /*
5827 * s[0] is a dummy entry to protect other BPF insn from damage
5828 * by s[fix] = foo with uninitialized variable "fix". It is somewhat
5829 * hard to find interdependency made by jump table fixup.
5830 */
5831 i = 0;
5832 s[i] = new_stmt(cstate, 0); /*dummy*/
5833 i++;
5834
5835 switch (proto) {
5836 case Q_IP:
5837 b0 = gen_linktype(cstate, ETHERTYPE_IP);
5838
5839 /* A = ip->ip_p */
5840 s[i] = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B);
5841 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 9;
5842 i++;
5843 /* X = ip->ip_hl << 2 */
5844 s[i] = new_stmt(cstate, BPF_LDX|BPF_MSH|BPF_B);
5845 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
5846 i++;
5847 break;
5848
5849 case Q_IPV6:
5850 b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
5851
5852 /* A = ip6->ip_nxt */
5853 s[i] = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B);
5854 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 6;
5855 i++;
5856 /* X = sizeof(struct ip6_hdr) */
5857 s[i] = new_stmt(cstate, BPF_LDX|BPF_IMM);
5858 s[i]->s.k = 40;
5859 i++;
5860 break;
5861
5862 default:
5863 bpf_error(cstate, "unsupported proto to gen_protochain");
5864 /*NOTREACHED*/
5865 }
5866
5867 /* again: if (A == v) goto end; else fall through; */
5868 again = i;
5869 s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5870 s[i]->s.k = v;
5871 s[i]->s.jt = NULL; /*later*/
5872 s[i]->s.jf = NULL; /*update in next stmt*/
5873 fix5 = i;
5874 i++;
5875
5876#ifndef IPPROTO_NONE
5877#define IPPROTO_NONE 59
5878#endif
5879 /* if (A == IPPROTO_NONE) goto end */
5880 s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5881 s[i]->s.jt = NULL; /*later*/
5882 s[i]->s.jf = NULL; /*update in next stmt*/
5883 s[i]->s.k = IPPROTO_NONE;
5884 s[fix5]->s.jf = s[i];
5885 fix2 = i;
5886 i++;
5887
5888 if (proto == Q_IPV6) {
5889 int v6start, v6end, v6advance, j;
5890
5891 v6start = i;
5892 /* if (A == IPPROTO_HOPOPTS) goto v6advance */
5893 s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5894 s[i]->s.jt = NULL; /*later*/
5895 s[i]->s.jf = NULL; /*update in next stmt*/
5896 s[i]->s.k = IPPROTO_HOPOPTS;
5897 s[fix2]->s.jf = s[i];
5898 i++;
5899 /* if (A == IPPROTO_DSTOPTS) goto v6advance */
5900 s[i - 1]->s.jf = s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5901 s[i]->s.jt = NULL; /*later*/
5902 s[i]->s.jf = NULL; /*update in next stmt*/
5903 s[i]->s.k = IPPROTO_DSTOPTS;
5904 i++;
5905 /* if (A == IPPROTO_ROUTING) goto v6advance */
5906 s[i - 1]->s.jf = s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5907 s[i]->s.jt = NULL; /*later*/
5908 s[i]->s.jf = NULL; /*update in next stmt*/
5909 s[i]->s.k = IPPROTO_ROUTING;
5910 i++;
5911 /* if (A == IPPROTO_FRAGMENT) goto v6advance; else goto ahcheck; */
5912 s[i - 1]->s.jf = s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5913 s[i]->s.jt = NULL; /*later*/
5914 s[i]->s.jf = NULL; /*later*/
5915 s[i]->s.k = IPPROTO_FRAGMENT;
5916 fix3 = i;
5917 v6end = i;
5918 i++;
5919
5920 /* v6advance: */
5921 v6advance = i;
5922
5923 /*
5924 * in short,
5925 * A = P[X + packet head];
5926 * X = X + (P[X + packet head + 1] + 1) * 8;
5927 */
5928 /* A = P[X + packet head] */
5929 s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
5930 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
5931 i++;
5932 /* MEM[reg2] = A */
5933 s[i] = new_stmt(cstate, BPF_ST);
5934 s[i]->s.k = reg2;
5935 i++;
5936 /* A = P[X + packet head + 1]; */
5937 s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
5938 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 1;
5939 i++;
5940 /* A += 1 */
5941 s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
5942 s[i]->s.k = 1;
5943 i++;
5944 /* A *= 8 */
5945 s[i] = new_stmt(cstate, BPF_ALU|BPF_MUL|BPF_K);
5946 s[i]->s.k = 8;
5947 i++;
5948 /* A += X */
5949 s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X);
5950 s[i]->s.k = 0;
5951 i++;
5952 /* X = A; */
5953 s[i] = new_stmt(cstate, BPF_MISC|BPF_TAX);
5954 i++;
5955 /* A = MEM[reg2] */
5956 s[i] = new_stmt(cstate, BPF_LD|BPF_MEM);
5957 s[i]->s.k = reg2;
5958 i++;
5959
5960 /* goto again; (must use BPF_JA for backward jump) */
5961 s[i] = new_stmt(cstate, BPF_JMP|BPF_JA);
5962 s[i]->s.k = again - i - 1;
5963 s[i - 1]->s.jf = s[i];
5964 i++;
5965
5966 /* fixup */
5967 for (j = v6start; j <= v6end; j++)
5968 s[j]->s.jt = s[v6advance];
5969 } else {
5970 /* nop */
5971 s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
5972 s[i]->s.k = 0;
5973 s[fix2]->s.jf = s[i];
5974 i++;
5975 }
5976
5977 /* ahcheck: */
5978 ahcheck = i;
5979 /* if (A == IPPROTO_AH) then fall through; else goto end; */
5980 s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5981 s[i]->s.jt = NULL; /*later*/
5982 s[i]->s.jf = NULL; /*later*/
5983 s[i]->s.k = IPPROTO_AH;
5984 if (fix3)
5985 s[fix3]->s.jf = s[ahcheck];
5986 fix4 = i;
5987 i++;
5988
5989 /*
5990 * in short,
5991 * A = P[X];
5992 * X = X + (P[X + 1] + 2) * 4;
5993 */
5994 /* A = X */
5995 s[i - 1]->s.jt = s[i] = new_stmt(cstate, BPF_MISC|BPF_TXA);
5996 i++;
5997 /* A = P[X + packet head]; */
5998 s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
5999 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
6000 i++;
6001 /* MEM[reg2] = A */
6002 s[i] = new_stmt(cstate, BPF_ST);
6003 s[i]->s.k = reg2;
6004 i++;
6005 /* A = X */
6006 s[i - 1]->s.jt = s[i] = new_stmt(cstate, BPF_MISC|BPF_TXA);
6007 i++;
6008 /* A += 1 */
6009 s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
6010 s[i]->s.k = 1;
6011 i++;
6012 /* X = A */
6013 s[i] = new_stmt(cstate, BPF_MISC|BPF_TAX);
6014 i++;
6015 /* A = P[X + packet head] */
6016 s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
6017 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
6018 i++;
6019 /* A += 2 */
6020 s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
6021 s[i]->s.k = 2;
6022 i++;
6023 /* A *= 4 */
6024 s[i] = new_stmt(cstate, BPF_ALU|BPF_MUL|BPF_K);
6025 s[i]->s.k = 4;
6026 i++;
6027 /* X = A; */
6028 s[i] = new_stmt(cstate, BPF_MISC|BPF_TAX);
6029 i++;
6030 /* A = MEM[reg2] */
6031 s[i] = new_stmt(cstate, BPF_LD|BPF_MEM);
6032 s[i]->s.k = reg2;
6033 i++;
6034
6035 /* goto again; (must use BPF_JA for backward jump) */
6036 s[i] = new_stmt(cstate, BPF_JMP|BPF_JA);
6037 s[i]->s.k = again - i - 1;
6038 i++;
6039
6040 /* end: nop */
6041 end = i;
6042 s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
6043 s[i]->s.k = 0;
6044 s[fix2]->s.jt = s[end];
6045 s[fix4]->s.jf = s[end];
6046 s[fix5]->s.jt = s[end];
6047 i++;
6048
6049 /*
6050 * make slist chain
6051 */
6052 max = i;
6053 for (i = 0; i < max - 1; i++)
6054 s[i]->next = s[i + 1];
6055 s[max - 1]->next = NULL;
6056
6057 /*
6058 * emit final check
6059 */
6060 b = new_block(cstate, JMP(BPF_JEQ));
6061 b->stmts = s[1]; /*remember, s[0] is dummy*/
6062 b->s.k = v;
6063
6064 free_reg(cstate, reg2);
6065
6066 gen_and(b0, b);
6067 return b;
6068#endif
6069}
6070
6071static struct block *
6072gen_check_802_11_data_frame(compiler_state_t *cstate)
6073{
6074 struct slist *s;
6075 struct block *b0, *b1;
6076
6077 /*
6078 * A data frame has the 0x08 bit (b3) in the frame control field set
6079 * and the 0x04 bit (b2) clear.
6080 */
6081 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
6082 b0 = new_block(cstate, JMP(BPF_JSET));
6083 b0->s.k = 0x08;
6084 b0->stmts = s;
6085
6086 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
6087 b1 = new_block(cstate, JMP(BPF_JSET));
6088 b1->s.k = 0x04;
6089 b1->stmts = s;
6090 gen_not(b1);
6091
6092 gen_and(b1, b0);
6093
6094 return b0;
6095}
6096
6097/*
6098 * Generate code that checks whether the packet is a packet for protocol
6099 * <proto> and whether the type field in that protocol's header has
6100 * the value <v>, e.g. if <proto> is Q_IP, it checks whether it's an
6101 * IP packet and checks the protocol number in the IP header against <v>.
6102 *
6103 * If <proto> is Q_DEFAULT, i.e. just "proto" was specified, it checks
6104 * against Q_IP and Q_IPV6.
6105 */
6106static struct block *
6107gen_proto(compiler_state_t *cstate, int v, int proto, int dir)
6108{
6109 struct block *b0, *b1;
6110#ifndef CHASE_CHAIN
6111 struct block *b2;
6112#endif
6113
6114 if (dir != Q_DEFAULT)
6115 bpf_error(cstate, "direction applied to 'proto'");
6116
6117 switch (proto) {
6118 case Q_DEFAULT:
6119 b0 = gen_proto(cstate, v, Q_IP, dir);
6120 b1 = gen_proto(cstate, v, Q_IPV6, dir);
6121 gen_or(b0, b1);
6122 return b1;
6123
6124 case Q_IP:
6125 /*
6126 * For FDDI, RFC 1188 says that SNAP encapsulation is used,
6127 * not LLC encapsulation with LLCSAP_IP.
6128 *
6129 * For IEEE 802 networks - which includes 802.5 token ring
6130 * (which is what DLT_IEEE802 means) and 802.11 - RFC 1042
6131 * says that SNAP encapsulation is used, not LLC encapsulation
6132 * with LLCSAP_IP.
6133 *
6134 * For LLC-encapsulated ATM/"Classical IP", RFC 1483 and
6135 * RFC 2225 say that SNAP encapsulation is used, not LLC
6136 * encapsulation with LLCSAP_IP.
6137 *
6138 * So we always check for ETHERTYPE_IP.
6139 */
6140 b0 = gen_linktype(cstate, ETHERTYPE_IP);
6141#ifndef CHASE_CHAIN
6142 b1 = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, (bpf_int32)v);
6143#else
6144 b1 = gen_protochain(cstate, v, Q_IP);
6145#endif
6146 gen_and(b0, b1);
6147 return b1;
6148
6149 case Q_ISO:
6150 switch (cstate->linktype) {
6151
6152 case DLT_FRELAY:
6153 /*
6154 * Frame Relay packets typically have an OSI
6155 * NLPID at the beginning; "gen_linktype(cstate, LLCSAP_ISONS)"
6156 * generates code to check for all the OSI
6157 * NLPIDs, so calling it and then adding a check
6158 * for the particular NLPID for which we're
6159 * looking is bogus, as we can just check for
6160 * the NLPID.
6161 *
6162 * What we check for is the NLPID and a frame
6163 * control field value of UI, i.e. 0x03 followed
6164 * by the NLPID.
6165 *
6166 * XXX - assumes a 2-byte Frame Relay header with
6167 * DLCI and flags. What if the address is longer?
6168 *
6169 * XXX - what about SNAP-encapsulated frames?
6170 */
6171 return gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | v);
6172 /*NOTREACHED*/
6173 break;
6174
6175 case DLT_C_HDLC:
6176 /*
6177 * Cisco uses an Ethertype lookalike - for OSI,
6178 * it's 0xfefe.
6179 */
6180 b0 = gen_linktype(cstate, LLCSAP_ISONS<<8 | LLCSAP_ISONS);
6181 /* OSI in C-HDLC is stuffed with a fudge byte */
6182 b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 1, BPF_B, (long)v);
6183 gen_and(b0, b1);
6184 return b1;
6185
6186 default:
6187 b0 = gen_linktype(cstate, LLCSAP_ISONS);
6188 b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 0, BPF_B, (long)v);
6189 gen_and(b0, b1);
6190 return b1;
6191 }
6192
6193 case Q_ISIS:
6194 b0 = gen_proto(cstate, ISO10589_ISIS, Q_ISO, Q_DEFAULT);
6195 /*
6196 * 4 is the offset of the PDU type relative to the IS-IS
6197 * header.
6198 */
6199 b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 4, BPF_B, (long)v);
6200 gen_and(b0, b1);
6201 return b1;
6202
6203 case Q_ARP:
6204 bpf_error(cstate, "arp does not encapsulate another protocol");
6205 /* NOTREACHED */
6206
6207 case Q_RARP:
6208 bpf_error(cstate, "rarp does not encapsulate another protocol");
6209 /* NOTREACHED */
6210
6211 case Q_ATALK:
6212 bpf_error(cstate, "atalk encapsulation is not specifiable");
6213 /* NOTREACHED */
6214
6215 case Q_DECNET:
6216 bpf_error(cstate, "decnet encapsulation is not specifiable");
6217 /* NOTREACHED */
6218
6219 case Q_SCA:
6220 bpf_error(cstate, "sca does not encapsulate another protocol");
6221 /* NOTREACHED */
6222
6223 case Q_LAT:
6224 bpf_error(cstate, "lat does not encapsulate another protocol");
6225 /* NOTREACHED */
6226
6227 case Q_MOPRC:
6228 bpf_error(cstate, "moprc does not encapsulate another protocol");
6229 /* NOTREACHED */
6230
6231 case Q_MOPDL:
6232 bpf_error(cstate, "mopdl does not encapsulate another protocol");
6233 /* NOTREACHED */
6234
6235 case Q_LINK:
6236 return gen_linktype(cstate, v);
6237
6238 case Q_UDP:
6239 bpf_error(cstate, "'udp proto' is bogus");
6240 /* NOTREACHED */
6241
6242 case Q_TCP:
6243 bpf_error(cstate, "'tcp proto' is bogus");
6244 /* NOTREACHED */
6245
6246 case Q_SCTP:
6247 bpf_error(cstate, "'sctp proto' is bogus");
6248 /* NOTREACHED */
6249
6250 case Q_ICMP:
6251 bpf_error(cstate, "'icmp proto' is bogus");
6252 /* NOTREACHED */
6253
6254 case Q_IGMP:
6255 bpf_error(cstate, "'igmp proto' is bogus");
6256 /* NOTREACHED */
6257
6258 case Q_IGRP:
6259 bpf_error(cstate, "'igrp proto' is bogus");
6260 /* NOTREACHED */
6261
6262 case Q_PIM:
6263 bpf_error(cstate, "'pim proto' is bogus");
6264 /* NOTREACHED */
6265
6266 case Q_VRRP:
6267 bpf_error(cstate, "'vrrp proto' is bogus");
6268 /* NOTREACHED */
6269
6270 case Q_CARP:
6271 bpf_error(cstate, "'carp proto' is bogus");
6272 /* NOTREACHED */
6273
6274 case Q_IPV6:
6275 b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
6276#ifndef CHASE_CHAIN
6277 /*
6278 * Also check for a fragment header before the final
6279 * header.
6280 */
6281 b2 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, IPPROTO_FRAGMENT);
6282 b1 = gen_cmp(cstate, OR_LINKPL, 40, BPF_B, (bpf_int32)v);
6283 gen_and(b2, b1);
6284 b2 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, (bpf_int32)v);
6285 gen_or(b2, b1);
6286#else
6287 b1 = gen_protochain(cstate, v, Q_IPV6);
6288#endif
6289 gen_and(b0, b1);
6290 return b1;
6291
6292 case Q_ICMPV6:
6293 bpf_error(cstate, "'icmp6 proto' is bogus");
6294
6295 case Q_AH:
6296 bpf_error(cstate, "'ah proto' is bogus");
6297
6298 case Q_ESP:
6299 bpf_error(cstate, "'ah proto' is bogus");
6300
6301 case Q_STP:
6302 bpf_error(cstate, "'stp proto' is bogus");
6303
6304 case Q_IPX:
6305 bpf_error(cstate, "'ipx proto' is bogus");
6306
6307 case Q_NETBEUI:
6308 bpf_error(cstate, "'netbeui proto' is bogus");
6309
6310 case Q_RADIO:
6311 bpf_error(cstate, "'radio proto' is bogus");
6312
6313 default:
6314 abort();
6315 /* NOTREACHED */
6316 }
6317 /* NOTREACHED */
6318}
6319
6320struct block *
6321gen_scode(compiler_state_t *cstate, const char *name, struct qual q)
6322{
6323 int proto = q.proto;
6324 int dir = q.dir;
6325 int tproto;
6326 u_char *eaddr;
6327 bpf_u_int32 mask, addr;
6328 struct addrinfo *res, *res0;
6329 struct sockaddr_in *sin4;
6330#ifdef INET6
6331 int tproto6;
6332 struct sockaddr_in6 *sin6;
6333 struct in6_addr mask128;
6334#endif /*INET6*/
6335 struct block *b, *tmp;
6336 int port, real_proto;
6337 int port1, port2;
6338
6339 switch (q.addr) {
6340
6341 case Q_NET:
6342 addr = pcap_nametonetaddr(name);
6343 if (addr == 0)
6344 bpf_error(cstate, "unknown network '%s'", name);
6345 /* Left justify network addr and calculate its network mask */
6346 mask = 0xffffffff;
6347 while (addr && (addr & 0xff000000) == 0) {
6348 addr <<= 8;
6349 mask <<= 8;
6350 }
6351 return gen_host(cstate, addr, mask, proto, dir, q.addr);
6352
6353 case Q_DEFAULT:
6354 case Q_HOST:
6355 if (proto == Q_LINK) {
6356 switch (cstate->linktype) {
6357
6358 case DLT_EN10MB:
6359 case DLT_NETANALYZER:
6360 case DLT_NETANALYZER_TRANSPARENT:
6361 eaddr = pcap_ether_hostton(name);
6362 if (eaddr == NULL)
6363 bpf_error(cstate,
6364 "unknown ether host '%s'", name);
6365 tmp = gen_prevlinkhdr_check(cstate);
6366 b = gen_ehostop(cstate, eaddr, dir);
6367 if (tmp != NULL)
6368 gen_and(tmp, b);
6369 free(eaddr);
6370 return b;
6371
6372 case DLT_FDDI:
6373 eaddr = pcap_ether_hostton(name);
6374 if (eaddr == NULL)
6375 bpf_error(cstate,
6376 "unknown FDDI host '%s'", name);
6377 b = gen_fhostop(cstate, eaddr, dir);
6378 free(eaddr);
6379 return b;
6380
6381 case DLT_IEEE802:
6382 eaddr = pcap_ether_hostton(name);
6383 if (eaddr == NULL)
6384 bpf_error(cstate,
6385 "unknown token ring host '%s'", name);
6386 b = gen_thostop(cstate, eaddr, dir);
6387 free(eaddr);
6388 return b;
6389
6390 case DLT_IEEE802_11:
6391 case DLT_PRISM_HEADER:
6392 case DLT_IEEE802_11_RADIO_AVS:
6393 case DLT_IEEE802_11_RADIO:
6394 case DLT_PPI:
6395 eaddr = pcap_ether_hostton(name);
6396 if (eaddr == NULL)
6397 bpf_error(cstate,
6398 "unknown 802.11 host '%s'", name);
6399 b = gen_wlanhostop(cstate, eaddr, dir);
6400 free(eaddr);
6401 return b;
6402
6403 case DLT_IP_OVER_FC:
6404 eaddr = pcap_ether_hostton(name);
6405 if (eaddr == NULL)
6406 bpf_error(cstate,
6407 "unknown Fibre Channel host '%s'", name);
6408 b = gen_ipfchostop(cstate, eaddr, dir);
6409 free(eaddr);
6410 return b;
6411 }
6412
6413 bpf_error(cstate, "only ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel supports link-level host name");
6414 } else if (proto == Q_DECNET) {
6415 unsigned short dn_addr;
6416
6417 if (!__pcap_nametodnaddr(name, &dn_addr)) {
6418#ifdef DECNETLIB
6419 bpf_error(cstate, "unknown decnet host name '%s'\n", name);
6420#else
6421 bpf_error(cstate, "decnet name support not included, '%s' cannot be translated\n",
6422 name);
6423#endif
6424 }
6425 /*
6426 * I don't think DECNET hosts can be multihomed, so
6427 * there is no need to build up a list of addresses
6428 */
6429 return (gen_host(cstate, dn_addr, 0, proto, dir, q.addr));
6430 } else {
6431#ifdef INET6
6432 memset(&mask128, 0xff, sizeof(mask128));
6433#endif
6434 res0 = res = pcap_nametoaddrinfo(name);
6435 if (res == NULL)
6436 bpf_error(cstate, "unknown host '%s'", name);
6437 cstate->ai = res;
6438 b = tmp = NULL;
6439 tproto = proto;
6440#ifdef INET6
6441 tproto6 = proto;
6442#endif
6443 if (cstate->off_linktype.constant_part == OFFSET_NOT_SET &&
6444 tproto == Q_DEFAULT) {
6445 tproto = Q_IP;
6446#ifdef INET6
6447 tproto6 = Q_IPV6;
6448#endif
6449 }
6450 for (res = res0; res; res = res->ai_next) {
6451 switch (res->ai_family) {
6452 case AF_INET:
6453#ifdef INET6
6454 if (tproto == Q_IPV6)
6455 continue;
6456#endif
6457
6458 sin4 = (struct sockaddr_in *)
6459 res->ai_addr;
6460 tmp = gen_host(cstate, ntohl(sin4->sin_addr.s_addr),
6461 0xffffffff, tproto, dir, q.addr);
6462 break;
6463#ifdef INET6
6464 case AF_INET6:
6465 if (tproto6 == Q_IP)
6466 continue;
6467
6468 sin6 = (struct sockaddr_in6 *)
6469 res->ai_addr;
6470 tmp = gen_host6(cstate, &sin6->sin6_addr,
6471 &mask128, tproto6, dir, q.addr);
6472 break;
6473#endif
6474 default:
6475 continue;
6476 }
6477 if (b)
6478 gen_or(b, tmp);
6479 b = tmp;
6480 }
6481 cstate->ai = NULL;
6482 freeaddrinfo(res0);
6483 if (b == NULL) {
6484 bpf_error(cstate, "unknown host '%s'%s", name,
6485 (proto == Q_DEFAULT)
6486 ? ""
6487 : " for specified address family");
6488 }
6489 return b;
6490 }
6491
6492 case Q_PORT:
6493 if (proto != Q_DEFAULT &&
6494 proto != Q_UDP && proto != Q_TCP && proto != Q_SCTP)
6495 bpf_error(cstate, "illegal qualifier of 'port'");
6496 if (pcap_nametoport(name, &port, &real_proto) == 0)
6497 bpf_error(cstate, "unknown port '%s'", name);
6498 if (proto == Q_UDP) {
6499 if (real_proto == IPPROTO_TCP)
6500 bpf_error(cstate, "port '%s' is tcp", name);
6501 else if (real_proto == IPPROTO_SCTP)
6502 bpf_error(cstate, "port '%s' is sctp", name);
6503 else
6504 /* override PROTO_UNDEF */
6505 real_proto = IPPROTO_UDP;
6506 }
6507 if (proto == Q_TCP) {
6508 if (real_proto == IPPROTO_UDP)
6509 bpf_error(cstate, "port '%s' is udp", name);
6510
6511 else if (real_proto == IPPROTO_SCTP)
6512 bpf_error(cstate, "port '%s' is sctp", name);
6513 else
6514 /* override PROTO_UNDEF */
6515 real_proto = IPPROTO_TCP;
6516 }
6517 if (proto == Q_SCTP) {
6518 if (real_proto == IPPROTO_UDP)
6519 bpf_error(cstate, "port '%s' is udp", name);
6520
6521 else if (real_proto == IPPROTO_TCP)
6522 bpf_error(cstate, "port '%s' is tcp", name);
6523 else
6524 /* override PROTO_UNDEF */
6525 real_proto = IPPROTO_SCTP;
6526 }
6527 if (port < 0)
6528 bpf_error(cstate, "illegal port number %d < 0", port);
6529 if (port > 65535)
6530 bpf_error(cstate, "illegal port number %d > 65535", port);
6531 b = gen_port(cstate, port, real_proto, dir);
6532 gen_or(gen_port6(cstate, port, real_proto, dir), b);
6533 return b;
6534
6535 case Q_PORTRANGE:
6536 if (proto != Q_DEFAULT &&
6537 proto != Q_UDP && proto != Q_TCP && proto != Q_SCTP)
6538 bpf_error(cstate, "illegal qualifier of 'portrange'");
6539 if (pcap_nametoportrange(name, &port1, &port2, &real_proto) == 0)
6540 bpf_error(cstate, "unknown port in range '%s'", name);
6541 if (proto == Q_UDP) {
6542 if (real_proto == IPPROTO_TCP)
6543 bpf_error(cstate, "port in range '%s' is tcp", name);
6544 else if (real_proto == IPPROTO_SCTP)
6545 bpf_error(cstate, "port in range '%s' is sctp", name);
6546 else
6547 /* override PROTO_UNDEF */
6548 real_proto = IPPROTO_UDP;
6549 }
6550 if (proto == Q_TCP) {
6551 if (real_proto == IPPROTO_UDP)
6552 bpf_error(cstate, "port in range '%s' is udp", name);
6553 else if (real_proto == IPPROTO_SCTP)
6554 bpf_error(cstate, "port in range '%s' is sctp", name);
6555 else
6556 /* override PROTO_UNDEF */
6557 real_proto = IPPROTO_TCP;
6558 }
6559 if (proto == Q_SCTP) {
6560 if (real_proto == IPPROTO_UDP)
6561 bpf_error(cstate, "port in range '%s' is udp", name);
6562 else if (real_proto == IPPROTO_TCP)
6563 bpf_error(cstate, "port in range '%s' is tcp", name);
6564 else
6565 /* override PROTO_UNDEF */
6566 real_proto = IPPROTO_SCTP;
6567 }
6568 if (port1 < 0)
6569 bpf_error(cstate, "illegal port number %d < 0", port1);
6570 if (port1 > 65535)
6571 bpf_error(cstate, "illegal port number %d > 65535", port1);
6572 if (port2 < 0)
6573 bpf_error(cstate, "illegal port number %d < 0", port2);
6574 if (port2 > 65535)
6575 bpf_error(cstate, "illegal port number %d > 65535", port2);
6576
6577 b = gen_portrange(cstate, port1, port2, real_proto, dir);
6578 gen_or(gen_portrange6(cstate, port1, port2, real_proto, dir), b);
6579 return b;
6580
6581 case Q_GATEWAY:
6582#ifndef INET6
6583 eaddr = pcap_ether_hostton(name);
6584 if (eaddr == NULL)
6585 bpf_error(cstate, "unknown ether host: %s", name);
6586
6587 res = pcap_nametoaddrinfo(name);
6588 cstate->ai = res;
6589 if (res == NULL)
6590 bpf_error(cstate, "unknown host '%s'", name);
6591 b = gen_gateway(cstate, eaddr, res, proto, dir);
6592 cstate->ai = NULL;
6593 freeaddrinfo(res);
6594 if (b == NULL)
6595 bpf_error(cstate, "unknown host '%s'", name);
6596 return b;
6597#else
6598 bpf_error(cstate, "'gateway' not supported in this configuration");
6599#endif /*INET6*/
6600
6601 case Q_PROTO:
6602 real_proto = lookup_proto(cstate, name, proto);
6603 if (real_proto >= 0)
6604 return gen_proto(cstate, real_proto, proto, dir);
6605 else
6606 bpf_error(cstate, "unknown protocol: %s", name);
6607
6608 case Q_PROTOCHAIN:
6609 real_proto = lookup_proto(cstate, name, proto);
6610 if (real_proto >= 0)
6611 return gen_protochain(cstate, real_proto, proto, dir);
6612 else
6613 bpf_error(cstate, "unknown protocol: %s", name);
6614
6615 case Q_UNDEF:
6616 syntax(cstate);
6617 /* NOTREACHED */
6618 }
6619 abort();
6620 /* NOTREACHED */
6621}
6622
6623struct block *
6624gen_mcode(compiler_state_t *cstate, const char *s1, const char *s2,
6625 unsigned int masklen, struct qual q)
6626{
6627 register int nlen, mlen;
6628 bpf_u_int32 n, m;
6629
6630 nlen = __pcap_atoin(s1, &n);
6631 /* Promote short ipaddr */
6632 n <<= 32 - nlen;
6633
6634 if (s2 != NULL) {
6635 mlen = __pcap_atoin(s2, &m);
6636 /* Promote short ipaddr */
6637 m <<= 32 - mlen;
6638 if ((n & ~m) != 0)
6639 bpf_error(cstate, "non-network bits set in \"%s mask %s\"",
6640 s1, s2);
6641 } else {
6642 /* Convert mask len to mask */
6643 if (masklen > 32)
6644 bpf_error(cstate, "mask length must be <= 32");
6645 if (masklen == 0) {
6646 /*
6647 * X << 32 is not guaranteed by C to be 0; it's
6648 * undefined.
6649 */
6650 m = 0;
6651 } else
6652 m = 0xffffffff << (32 - masklen);
6653 if ((n & ~m) != 0)
6654 bpf_error(cstate, "non-network bits set in \"%s/%d\"",
6655 s1, masklen);
6656 }
6657
6658 switch (q.addr) {
6659
6660 case Q_NET:
6661 return gen_host(cstate, n, m, q.proto, q.dir, q.addr);
6662
6663 default:
6664 bpf_error(cstate, "Mask syntax for networks only");
6665 /* NOTREACHED */
6666 }
6667 /* NOTREACHED */
6668}
6669
6670struct block *
6671gen_ncode(compiler_state_t *cstate, const char *s, bpf_u_int32 v, struct qual q)
6672{
6673 bpf_u_int32 mask;
6674 int proto = q.proto;
6675 int dir = q.dir;
6676 register int vlen;
6677
6678 if (s == NULL)
6679 vlen = 32;
6680 else if (q.proto == Q_DECNET) {
6681 vlen = __pcap_atodn(s, &v);
6682 if (vlen == 0)
6683 bpf_error(cstate, "malformed decnet address '%s'", s);
6684 } else
6685 vlen = __pcap_atoin(s, &v);
6686
6687 switch (q.addr) {
6688
6689 case Q_DEFAULT:
6690 case Q_HOST:
6691 case Q_NET:
6692 if (proto == Q_DECNET)
6693 return gen_host(cstate, v, 0, proto, dir, q.addr);
6694 else if (proto == Q_LINK) {
6695 bpf_error(cstate, "illegal link layer address");
6696 } else {
6697 mask = 0xffffffff;
6698 if (s == NULL && q.addr == Q_NET) {
6699 /* Promote short net number */
6700 while (v && (v & 0xff000000) == 0) {
6701 v <<= 8;
6702 mask <<= 8;
6703 }
6704 } else {
6705 /* Promote short ipaddr */
6706 v <<= 32 - vlen;
6707 mask <<= 32 - vlen ;
6708 }
6709 return gen_host(cstate, v, mask, proto, dir, q.addr);
6710 }
6711
6712 case Q_PORT:
6713 if (proto == Q_UDP)
6714 proto = IPPROTO_UDP;
6715 else if (proto == Q_TCP)
6716 proto = IPPROTO_TCP;
6717 else if (proto == Q_SCTP)
6718 proto = IPPROTO_SCTP;
6719 else if (proto == Q_DEFAULT)
6720 proto = PROTO_UNDEF;
6721 else
6722 bpf_error(cstate, "illegal qualifier of 'port'");
6723
6724 if (v > 65535)
6725 bpf_error(cstate, "illegal port number %u > 65535", v);
6726
6727 {
6728 struct block *b;
6729 b = gen_port(cstate, (int)v, proto, dir);
6730 gen_or(gen_port6(cstate, (int)v, proto, dir), b);
6731 return b;
6732 }
6733
6734 case Q_PORTRANGE:
6735 if (proto == Q_UDP)
6736 proto = IPPROTO_UDP;
6737 else if (proto == Q_TCP)
6738 proto = IPPROTO_TCP;
6739 else if (proto == Q_SCTP)
6740 proto = IPPROTO_SCTP;
6741 else if (proto == Q_DEFAULT)
6742 proto = PROTO_UNDEF;
6743 else
6744 bpf_error(cstate, "illegal qualifier of 'portrange'");
6745
6746 if (v > 65535)
6747 bpf_error(cstate, "illegal port number %u > 65535", v);
6748
6749 {
6750 struct block *b;
6751 b = gen_portrange(cstate, (int)v, (int)v, proto, dir);
6752 gen_or(gen_portrange6(cstate, (int)v, (int)v, proto, dir), b);
6753 return b;
6754 }
6755
6756 case Q_GATEWAY:
6757 bpf_error(cstate, "'gateway' requires a name");
6758 /* NOTREACHED */
6759
6760 case Q_PROTO:
6761 return gen_proto(cstate, (int)v, proto, dir);
6762
6763 case Q_PROTOCHAIN:
6764 return gen_protochain(cstate, (int)v, proto, dir);
6765
6766 case Q_UNDEF:
6767 syntax(cstate);
6768 /* NOTREACHED */
6769
6770 default:
6771 abort();
6772 /* NOTREACHED */
6773 }
6774 /* NOTREACHED */
6775}
6776
6777#ifdef INET6
6778struct block *
6779gen_mcode6(compiler_state_t *cstate, const char *s1, const char *s2,
6780 unsigned int masklen, struct qual q)
6781{
6782 struct addrinfo *res;
6783 struct in6_addr *addr;
6784 struct in6_addr mask;
6785 struct block *b;
6786 uint32_t *a, *m;
6787
6788 if (s2)
6789 bpf_error(cstate, "no mask %s supported", s2);
6790
6791 res = pcap_nametoaddrinfo(s1);
6792 if (!res)
6793 bpf_error(cstate, "invalid ip6 address %s", s1);
6794 cstate->ai = res;
6795 if (res->ai_next)
6796 bpf_error(cstate, "%s resolved to multiple address", s1);
6797 addr = &((struct sockaddr_in6 *)res->ai_addr)->sin6_addr;
6798
6799 if (sizeof(mask) * 8 < masklen)
6800 bpf_error(cstate, "mask length must be <= %u", (unsigned int)(sizeof(mask) * 8));
6801 memset(&mask, 0, sizeof(mask));
6802 memset(&mask, 0xff, masklen / 8);
6803 if (masklen % 8) {
6804 mask.s6_addr[masklen / 8] =
6805 (0xff << (8 - masklen % 8)) & 0xff;
6806 }
6807
6808 a = (uint32_t *)addr;
6809 m = (uint32_t *)&mask;
6810 if ((a[0] & ~m[0]) || (a[1] & ~m[1])
6811 || (a[2] & ~m[2]) || (a[3] & ~m[3])) {
6812 bpf_error(cstate, "non-network bits set in \"%s/%d\"", s1, masklen);
6813 }
6814
6815 switch (q.addr) {
6816
6817 case Q_DEFAULT:
6818 case Q_HOST:
6819 if (masklen != 128)
6820 bpf_error(cstate, "Mask syntax for networks only");
6821 /* FALLTHROUGH */
6822
6823 case Q_NET:
6824 b = gen_host6(cstate, addr, &mask, q.proto, q.dir, q.addr);
6825 cstate->ai = NULL;
6826 freeaddrinfo(res);
6827 return b;
6828
6829 default:
6830 bpf_error(cstate, "invalid qualifier against IPv6 address");
6831 /* NOTREACHED */
6832 }
6833}
6834#endif /*INET6*/
6835
6836struct block *
6837gen_ecode(compiler_state_t *cstate, const u_char *eaddr, struct qual q)
6838{
6839 struct block *b, *tmp;
6840
6841 if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK) {
6842 switch (cstate->linktype) {
6843 case DLT_EN10MB:
6844 case DLT_NETANALYZER:
6845 case DLT_NETANALYZER_TRANSPARENT:
6846 tmp = gen_prevlinkhdr_check(cstate);
6847 b = gen_ehostop(cstate, eaddr, (int)q.dir);
6848 if (tmp != NULL)
6849 gen_and(tmp, b);
6850 return b;
6851 case DLT_FDDI:
6852 return gen_fhostop(cstate, eaddr, (int)q.dir);
6853 case DLT_IEEE802:
6854 return gen_thostop(cstate, eaddr, (int)q.dir);
6855 case DLT_IEEE802_11:
6856 case DLT_PRISM_HEADER:
6857 case DLT_IEEE802_11_RADIO_AVS:
6858 case DLT_IEEE802_11_RADIO:
6859 case DLT_PPI:
6860 return gen_wlanhostop(cstate, eaddr, (int)q.dir);
6861 case DLT_IP_OVER_FC:
6862 return gen_ipfchostop(cstate, eaddr, (int)q.dir);
6863 default:
6864 bpf_error(cstate, "ethernet addresses supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
6865 break;
6866 }
6867 }
6868 bpf_error(cstate, "ethernet address used in non-ether expression");
6869 /* NOTREACHED */
6870}
6871
6872void
6873sappend(struct slist *s0, struct slist *s1)
6874{
6875 /*
6876 * This is definitely not the best way to do this, but the
6877 * lists will rarely get long.
6878 */
6879 while (s0->next)
6880 s0 = s0->next;
6881 s0->next = s1;
6882}
6883
6884static struct slist *
6885xfer_to_x(compiler_state_t *cstate, struct arth *a)
6886{
6887 struct slist *s;
6888
6889 s = new_stmt(cstate, BPF_LDX|BPF_MEM);
6890 s->s.k = a->regno;
6891 return s;
6892}
6893
6894static struct slist *
6895xfer_to_a(compiler_state_t *cstate, struct arth *a)
6896{
6897 struct slist *s;
6898
6899 s = new_stmt(cstate, BPF_LD|BPF_MEM);
6900 s->s.k = a->regno;
6901 return s;
6902}
6903
6904/*
6905 * Modify "index" to use the value stored into its register as an
6906 * offset relative to the beginning of the header for the protocol
6907 * "proto", and allocate a register and put an item "size" bytes long
6908 * (1, 2, or 4) at that offset into that register, making it the register
6909 * for "index".
6910 */
6911struct arth *
6912gen_load(compiler_state_t *cstate, int proto, struct arth *inst, int size)
6913{
6914 struct slist *s, *tmp;
6915 struct block *b;
6916 int regno = alloc_reg(cstate);
6917
6918 free_reg(cstate, inst->regno);
6919 switch (size) {
6920
6921 default:
6922 bpf_error(cstate, "data size must be 1, 2, or 4");
6923
6924 case 1:
6925 size = BPF_B;
6926 break;
6927
6928 case 2:
6929 size = BPF_H;
6930 break;
6931
6932 case 4:
6933 size = BPF_W;
6934 break;
6935 }
6936 switch (proto) {
6937 default:
6938 bpf_error(cstate, "unsupported index operation");
6939
6940 case Q_RADIO:
6941 /*
6942 * The offset is relative to the beginning of the packet
6943 * data, if we have a radio header. (If we don't, this
6944 * is an error.)
6945 */
6946 if (cstate->linktype != DLT_IEEE802_11_RADIO_AVS &&
6947 cstate->linktype != DLT_IEEE802_11_RADIO &&
6948 cstate->linktype != DLT_PRISM_HEADER)
6949 bpf_error(cstate, "radio information not present in capture");
6950
6951 /*
6952 * Load into the X register the offset computed into the
6953 * register specified by "index".
6954 */
6955 s = xfer_to_x(cstate, inst);
6956
6957 /*
6958 * Load the item at that offset.
6959 */
6960 tmp = new_stmt(cstate, BPF_LD|BPF_IND|size);
6961 sappend(s, tmp);
6962 sappend(inst->s, s);
6963 break;
6964
6965 case Q_LINK:
6966 /*
6967 * The offset is relative to the beginning of
6968 * the link-layer header.
6969 *
6970 * XXX - what about ATM LANE? Should the index be
6971 * relative to the beginning of the AAL5 frame, so
6972 * that 0 refers to the beginning of the LE Control
6973 * field, or relative to the beginning of the LAN
6974 * frame, so that 0 refers, for Ethernet LANE, to
6975 * the beginning of the destination address?
6976 */
6977 s = gen_abs_offset_varpart(cstate, &cstate->off_linkhdr);
6978
6979 /*
6980 * If "s" is non-null, it has code to arrange that the
6981 * X register contains the length of the prefix preceding
6982 * the link-layer header. Add to it the offset computed
6983 * into the register specified by "index", and move that
6984 * into the X register. Otherwise, just load into the X
6985 * register the offset computed into the register specified
6986 * by "index".
6987 */
6988 if (s != NULL) {
6989 sappend(s, xfer_to_a(cstate, inst));
6990 sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
6991 sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
6992 } else
6993 s = xfer_to_x(cstate, inst);
6994
6995 /*
6996 * Load the item at the sum of the offset we've put in the
6997 * X register and the offset of the start of the link
6998 * layer header (which is 0 if the radio header is
6999 * variable-length; that header length is what we put
7000 * into the X register and then added to the index).
7001 */
7002 tmp = new_stmt(cstate, BPF_LD|BPF_IND|size);
7003 tmp->s.k = cstate->off_linkhdr.constant_part;
7004 sappend(s, tmp);
7005 sappend(inst->s, s);
7006 break;
7007
7008 case Q_IP:
7009 case Q_ARP:
7010 case Q_RARP:
7011 case Q_ATALK:
7012 case Q_DECNET:
7013 case Q_SCA:
7014 case Q_LAT:
7015 case Q_MOPRC:
7016 case Q_MOPDL:
7017 case Q_IPV6:
7018 /*
7019 * The offset is relative to the beginning of
7020 * the network-layer header.
7021 * XXX - are there any cases where we want
7022 * cstate->off_nl_nosnap?
7023 */
7024 s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl);
7025
7026 /*
7027 * If "s" is non-null, it has code to arrange that the
7028 * X register contains the variable part of the offset
7029 * of the link-layer payload. Add to it the offset
7030 * computed into the register specified by "index",
7031 * and move that into the X register. Otherwise, just
7032 * load into the X register the offset computed into
7033 * the register specified by "index".
7034 */
7035 if (s != NULL) {
7036 sappend(s, xfer_to_a(cstate, inst));
7037 sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
7038 sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
7039 } else
7040 s = xfer_to_x(cstate, inst);
7041
7042 /*
7043 * Load the item at the sum of the offset we've put in the
7044 * X register, the offset of the start of the network
7045 * layer header from the beginning of the link-layer
7046 * payload, and the constant part of the offset of the
7047 * start of the link-layer payload.
7048 */
7049 tmp = new_stmt(cstate, BPF_LD|BPF_IND|size);
7050 tmp->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
7051 sappend(s, tmp);
7052 sappend(inst->s, s);
7053
7054 /*
7055 * Do the computation only if the packet contains
7056 * the protocol in question.
7057 */
7058 b = gen_proto_abbrev(cstate, proto);
7059 if (inst->b)
7060 gen_and(inst->b, b);
7061 inst->b = b;
7062 break;
7063
7064 case Q_SCTP:
7065 case Q_TCP:
7066 case Q_UDP:
7067 case Q_ICMP:
7068 case Q_IGMP:
7069 case Q_IGRP:
7070 case Q_PIM:
7071 case Q_VRRP:
7072 case Q_CARP:
7073 /*
7074 * The offset is relative to the beginning of
7075 * the transport-layer header.
7076 *
7077 * Load the X register with the length of the IPv4 header
7078 * (plus the offset of the link-layer header, if it's
7079 * a variable-length header), in bytes.
7080 *
7081 * XXX - are there any cases where we want
7082 * cstate->off_nl_nosnap?
7083 * XXX - we should, if we're built with
7084 * IPv6 support, generate code to load either
7085 * IPv4, IPv6, or both, as appropriate.
7086 */
7087 s = gen_loadx_iphdrlen(cstate);
7088
7089 /*
7090 * The X register now contains the sum of the variable
7091 * part of the offset of the link-layer payload and the
7092 * length of the network-layer header.
7093 *
7094 * Load into the A register the offset relative to
7095 * the beginning of the transport layer header,
7096 * add the X register to that, move that to the
7097 * X register, and load with an offset from the
7098 * X register equal to the sum of the constant part of
7099 * the offset of the link-layer payload and the offset,
7100 * relative to the beginning of the link-layer payload,
7101 * of the network-layer header.
7102 */
7103 sappend(s, xfer_to_a(cstate, inst));
7104 sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
7105 sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
7106 sappend(s, tmp = new_stmt(cstate, BPF_LD|BPF_IND|size));
7107 tmp->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
7108 sappend(inst->s, s);
7109
7110 /*
7111 * Do the computation only if the packet contains
7112 * the protocol in question - which is true only
7113 * if this is an IP datagram and is the first or
7114 * only fragment of that datagram.
7115 */
7116 gen_and(gen_proto_abbrev(cstate, proto), b = gen_ipfrag(cstate));
7117 if (inst->b)
7118 gen_and(inst->b, b);
7119 gen_and(gen_proto_abbrev(cstate, Q_IP), b);
7120 inst->b = b;
7121 break;
7122 case Q_ICMPV6:
7123 /*
7124 * Do the computation only if the packet contains
7125 * the protocol in question.
7126 */
7127 b = gen_proto_abbrev(cstate, Q_IPV6);
7128 if (inst->b) {
7129 gen_and(inst->b, b);
7130 }
7131 inst->b = b;
7132
7133 /*
7134 * Check if we have an icmp6 next header
7135 */
7136 b = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, 58);
7137 if (inst->b) {
7138 gen_and(inst->b, b);
7139 }
7140 inst->b = b;
7141
7142
7143 s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl);
7144 /*
7145 * If "s" is non-null, it has code to arrange that the
7146 * X register contains the variable part of the offset
7147 * of the link-layer payload. Add to it the offset
7148 * computed into the register specified by "index",
7149 * and move that into the X register. Otherwise, just
7150 * load into the X register the offset computed into
7151 * the register specified by "index".
7152 */
7153 if (s != NULL) {
7154 sappend(s, xfer_to_a(cstate, inst));
7155 sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
7156 sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
7157 } else {
7158 s = xfer_to_x(cstate, inst);
7159 }
7160
7161 /*
7162 * Load the item at the sum of the offset we've put in the
7163 * X register, the offset of the start of the network
7164 * layer header from the beginning of the link-layer
7165 * payload, and the constant part of the offset of the
7166 * start of the link-layer payload.
7167 */
7168 tmp = new_stmt(cstate, BPF_LD|BPF_IND|size);
7169 tmp->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 40;
7170
7171 sappend(s, tmp);
7172 sappend(inst->s, s);
7173
7174 break;
7175 }
7176 inst->regno = regno;
7177 s = new_stmt(cstate, BPF_ST);
7178 s->s.k = regno;
7179 sappend(inst->s, s);
7180
7181 return inst;
7182}
7183
7184struct block *
7185gen_relation(compiler_state_t *cstate, int code, struct arth *a0,
7186 struct arth *a1, int reversed)
7187{
7188 struct slist *s0, *s1, *s2;
7189 struct block *b, *tmp;
7190
7191 s0 = xfer_to_x(cstate, a1);
7192 s1 = xfer_to_a(cstate, a0);
7193 if (code == BPF_JEQ) {
7194 s2 = new_stmt(cstate, BPF_ALU|BPF_SUB|BPF_X);
7195 b = new_block(cstate, JMP(code));
7196 sappend(s1, s2);
7197 }
7198 else
7199 b = new_block(cstate, BPF_JMP|code|BPF_X);
7200 if (reversed)
7201 gen_not(b);
7202
7203 sappend(s0, s1);
7204 sappend(a1->s, s0);
7205 sappend(a0->s, a1->s);
7206
7207 b->stmts = a0->s;
7208
7209 free_reg(cstate, a0->regno);
7210 free_reg(cstate, a1->regno);
7211
7212 /* 'and' together protocol checks */
7213 if (a0->b) {
7214 if (a1->b) {
7215 gen_and(a0->b, tmp = a1->b);
7216 }
7217 else
7218 tmp = a0->b;
7219 } else
7220 tmp = a1->b;
7221
7222 if (tmp)
7223 gen_and(tmp, b);
7224
7225 return b;
7226}
7227
7228struct arth *
7229gen_loadlen(compiler_state_t *cstate)
7230{
7231 int regno = alloc_reg(cstate);
7232 struct arth *a = (struct arth *)newchunk(cstate, sizeof(*a));
7233 struct slist *s;
7234
7235 s = new_stmt(cstate, BPF_LD|BPF_LEN);
7236 s->next = new_stmt(cstate, BPF_ST);
7237 s->next->s.k = regno;
7238 a->s = s;
7239 a->regno = regno;
7240
7241 return a;
7242}
7243
7244struct arth *
7245gen_loadi(compiler_state_t *cstate, int val)
7246{
7247 struct arth *a;
7248 struct slist *s;
7249 int reg;
7250
7251 a = (struct arth *)newchunk(cstate, sizeof(*a));
7252
7253 reg = alloc_reg(cstate);
7254
7255 s = new_stmt(cstate, BPF_LD|BPF_IMM);
7256 s->s.k = val;
7257 s->next = new_stmt(cstate, BPF_ST);
7258 s->next->s.k = reg;
7259 a->s = s;
7260 a->regno = reg;
7261
7262 return a;
7263}
7264
7265struct arth *
7266gen_neg(compiler_state_t *cstate, struct arth *a)
7267{
7268 struct slist *s;
7269
7270 s = xfer_to_a(cstate, a);
7271 sappend(a->s, s);
7272 s = new_stmt(cstate, BPF_ALU|BPF_NEG);
7273 s->s.k = 0;
7274 sappend(a->s, s);
7275 s = new_stmt(cstate, BPF_ST);
7276 s->s.k = a->regno;
7277 sappend(a->s, s);
7278
7279 return a;
7280}
7281
7282struct arth *
7283gen_arth(compiler_state_t *cstate, int code, struct arth *a0,
7284 struct arth *a1)
7285{
7286 struct slist *s0, *s1, *s2;
7287
7288 /*
7289 * Disallow division by, or modulus by, zero; we do this here
7290 * so that it gets done even if the optimizer is disabled.
7291 */
7292 if (code == BPF_DIV) {
7293 if (a1->s->s.code == (BPF_LD|BPF_IMM) && a1->s->s.k == 0)
7294 bpf_error(cstate, "division by zero");
7295 } else if (code == BPF_MOD) {
7296 if (a1->s->s.code == (BPF_LD|BPF_IMM) && a1->s->s.k == 0)
7297 bpf_error(cstate, "modulus by zero");
7298 }
7299 s0 = xfer_to_x(cstate, a1);
7300 s1 = xfer_to_a(cstate, a0);
7301 s2 = new_stmt(cstate, BPF_ALU|BPF_X|code);
7302
7303 sappend(s1, s2);
7304 sappend(s0, s1);
7305 sappend(a1->s, s0);
7306 sappend(a0->s, a1->s);
7307
7308 free_reg(cstate, a0->regno);
7309 free_reg(cstate, a1->regno);
7310
7311 s0 = new_stmt(cstate, BPF_ST);
7312 a0->regno = s0->s.k = alloc_reg(cstate);
7313 sappend(a0->s, s0);
7314
7315 return a0;
7316}
7317
7318/*
7319 * Initialize the table of used registers and the current register.
7320 */
7321static void
7322init_regs(compiler_state_t *cstate)
7323{
7324 cstate->curreg = 0;
7325 memset(cstate->regused, 0, sizeof cstate->regused);
7326}
7327
7328/*
7329 * Return the next free register.
7330 */
7331static int
7332alloc_reg(compiler_state_t *cstate)
7333{
7334 int n = BPF_MEMWORDS;
7335
7336 while (--n >= 0) {
7337 if (cstate->regused[cstate->curreg])
7338 cstate->curreg = (cstate->curreg + 1) % BPF_MEMWORDS;
7339 else {
7340 cstate->regused[cstate->curreg] = 1;
7341 return cstate->curreg;
7342 }
7343 }
7344 bpf_error(cstate, "too many registers needed to evaluate expression");
7345 /* NOTREACHED */
7346}
7347
7348/*
7349 * Return a register to the table so it can
7350 * be used later.
7351 */
7352static void
7353free_reg(compiler_state_t *cstate, int n)
7354{
7355 cstate->regused[n] = 0;
7356}
7357
7358static struct block *
7359gen_len(compiler_state_t *cstate, int jmp, int n)
7360{
7361 struct slist *s;
7362 struct block *b;
7363
7364 s = new_stmt(cstate, BPF_LD|BPF_LEN);
7365 b = new_block(cstate, JMP(jmp));
7366 b->stmts = s;
7367 b->s.k = n;
7368
7369 return b;
7370}
7371
7372struct block *
7373gen_greater(compiler_state_t *cstate, int n)
7374{
7375 return gen_len(cstate, BPF_JGE, n);
7376}
7377
7378/*
7379 * Actually, this is less than or equal.
7380 */
7381struct block *
7382gen_less(compiler_state_t *cstate, int n)
7383{
7384 struct block *b;
7385
7386 b = gen_len(cstate, BPF_JGT, n);
7387 gen_not(b);
7388
7389 return b;
7390}
7391
7392/*
7393 * This is for "byte {idx} {op} {val}"; "idx" is treated as relative to
7394 * the beginning of the link-layer header.
7395 * XXX - that means you can't test values in the radiotap header, but
7396 * as that header is difficult if not impossible to parse generally
7397 * without a loop, that might not be a severe problem. A new keyword
7398 * "radio" could be added for that, although what you'd really want
7399 * would be a way of testing particular radio header values, which
7400 * would generate code appropriate to the radio header in question.
7401 */
7402struct block *
7403gen_byteop(compiler_state_t *cstate, int op, int idx, int val)
7404{
7405 struct block *b;
7406 struct slist *s;
7407
7408 switch (op) {
7409 default:
7410 abort();
7411
7412 case '=':
7413 return gen_cmp(cstate, OR_LINKHDR, (u_int)idx, BPF_B, (bpf_int32)val);
7414
7415 case '<':
7416 b = gen_cmp_lt(cstate, OR_LINKHDR, (u_int)idx, BPF_B, (bpf_int32)val);
7417 return b;
7418
7419 case '>':
7420 b = gen_cmp_gt(cstate, OR_LINKHDR, (u_int)idx, BPF_B, (bpf_int32)val);
7421 return b;
7422
7423 case '|':
7424 s = new_stmt(cstate, BPF_ALU|BPF_OR|BPF_K);
7425 break;
7426
7427 case '&':
7428 s = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
7429 break;
7430 }
7431 s->s.k = val;
7432 b = new_block(cstate, JMP(BPF_JEQ));
7433 b->stmts = s;
7434 gen_not(b);
7435
7436 return b;
7437}
7438
7439static const u_char abroadcast[] = { 0x0 };
7440
7441struct block *
7442gen_broadcast(compiler_state_t *cstate, int proto)
7443{
7444 bpf_u_int32 hostmask;
7445 struct block *b0, *b1, *b2;
7446 static const u_char ebroadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
7447
7448 switch (proto) {
7449
7450 case Q_DEFAULT:
7451 case Q_LINK:
7452 switch (cstate->linktype) {
7453 case DLT_ARCNET:
7454 case DLT_ARCNET_LINUX:
7455 return gen_ahostop(cstate, abroadcast, Q_DST);
7456 case DLT_EN10MB:
7457 case DLT_NETANALYZER:
7458 case DLT_NETANALYZER_TRANSPARENT:
7459 b1 = gen_prevlinkhdr_check(cstate);
7460 b0 = gen_ehostop(cstate, ebroadcast, Q_DST);
7461 if (b1 != NULL)
7462 gen_and(b1, b0);
7463 return b0;
7464 case DLT_FDDI:
7465 return gen_fhostop(cstate, ebroadcast, Q_DST);
7466 case DLT_IEEE802:
7467 return gen_thostop(cstate, ebroadcast, Q_DST);
7468 case DLT_IEEE802_11:
7469 case DLT_PRISM_HEADER:
7470 case DLT_IEEE802_11_RADIO_AVS:
7471 case DLT_IEEE802_11_RADIO:
7472 case DLT_PPI:
7473 return gen_wlanhostop(cstate, ebroadcast, Q_DST);
7474 case DLT_IP_OVER_FC:
7475 return gen_ipfchostop(cstate, ebroadcast, Q_DST);
7476 default:
7477 bpf_error(cstate, "not a broadcast link");
7478 }
7479 break;
7480
7481 case Q_IP:
7482 /*
7483 * We treat a netmask of PCAP_NETMASK_UNKNOWN (0xffffffff)
7484 * as an indication that we don't know the netmask, and fail
7485 * in that case.
7486 */
7487 if (cstate->netmask == PCAP_NETMASK_UNKNOWN)
7488 bpf_error(cstate, "netmask not known, so 'ip broadcast' not supported");
7489 b0 = gen_linktype(cstate, ETHERTYPE_IP);
7490 hostmask = ~cstate->netmask;
7491 b1 = gen_mcmp(cstate, OR_LINKPL, 16, BPF_W, (bpf_int32)0, hostmask);
7492 b2 = gen_mcmp(cstate, OR_LINKPL, 16, BPF_W,
7493 (bpf_int32)(~0 & hostmask), hostmask);
7494 gen_or(b1, b2);
7495 gen_and(b0, b2);
7496 return b2;
7497 }
7498 bpf_error(cstate, "only link-layer/IP broadcast filters supported");
7499 /* NOTREACHED */
7500}
7501
7502/*
7503 * Generate code to test the low-order bit of a MAC address (that's
7504 * the bottom bit of the *first* byte).
7505 */
7506static struct block *
7507gen_mac_multicast(compiler_state_t *cstate, int offset)
7508{
7509 register struct block *b0;
7510 register struct slist *s;
7511
7512 /* link[offset] & 1 != 0 */
7513 s = gen_load_a(cstate, OR_LINKHDR, offset, BPF_B);
7514 b0 = new_block(cstate, JMP(BPF_JSET));
7515 b0->s.k = 1;
7516 b0->stmts = s;
7517 return b0;
7518}
7519
7520struct block *
7521gen_multicast(compiler_state_t *cstate, int proto)
7522{
7523 register struct block *b0, *b1, *b2;
7524 register struct slist *s;
7525
7526 switch (proto) {
7527
7528 case Q_DEFAULT:
7529 case Q_LINK:
7530 switch (cstate->linktype) {
7531 case DLT_ARCNET:
7532 case DLT_ARCNET_LINUX:
7533 /* all ARCnet multicasts use the same address */
7534 return gen_ahostop(cstate, abroadcast, Q_DST);
7535 case DLT_EN10MB:
7536 case DLT_NETANALYZER:
7537 case DLT_NETANALYZER_TRANSPARENT:
7538 b1 = gen_prevlinkhdr_check(cstate);
7539 /* ether[0] & 1 != 0 */
7540 b0 = gen_mac_multicast(cstate, 0);
7541 if (b1 != NULL)
7542 gen_and(b1, b0);
7543 return b0;
7544 case DLT_FDDI:
7545 /*
7546 * XXX TEST THIS: MIGHT NOT PORT PROPERLY XXX
7547 *
7548 * XXX - was that referring to bit-order issues?
7549 */
7550 /* fddi[1] & 1 != 0 */
7551 return gen_mac_multicast(cstate, 1);
7552 case DLT_IEEE802:
7553 /* tr[2] & 1 != 0 */
7554 return gen_mac_multicast(cstate, 2);
7555 case DLT_IEEE802_11:
7556 case DLT_PRISM_HEADER:
7557 case DLT_IEEE802_11_RADIO_AVS:
7558 case DLT_IEEE802_11_RADIO:
7559 case DLT_PPI:
7560 /*
7561 * Oh, yuk.
7562 *
7563 * For control frames, there is no DA.
7564 *
7565 * For management frames, DA is at an
7566 * offset of 4 from the beginning of
7567 * the packet.
7568 *
7569 * For data frames, DA is at an offset
7570 * of 4 from the beginning of the packet
7571 * if To DS is clear and at an offset of
7572 * 16 from the beginning of the packet
7573 * if To DS is set.
7574 */
7575
7576 /*
7577 * Generate the tests to be done for data frames.
7578 *
7579 * First, check for To DS set, i.e. "link[1] & 0x01".
7580 */
7581 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
7582 b1 = new_block(cstate, JMP(BPF_JSET));
7583 b1->s.k = 0x01; /* To DS */
7584 b1->stmts = s;
7585
7586 /*
7587 * If To DS is set, the DA is at 16.
7588 */
7589 b0 = gen_mac_multicast(cstate, 16);
7590 gen_and(b1, b0);
7591
7592 /*
7593 * Now, check for To DS not set, i.e. check
7594 * "!(link[1] & 0x01)".
7595 */
7596 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
7597 b2 = new_block(cstate, JMP(BPF_JSET));
7598 b2->s.k = 0x01; /* To DS */
7599 b2->stmts = s;
7600 gen_not(b2);
7601
7602 /*
7603 * If To DS is not set, the DA is at 4.
7604 */
7605 b1 = gen_mac_multicast(cstate, 4);
7606 gen_and(b2, b1);
7607
7608 /*
7609 * Now OR together the last two checks. That gives
7610 * the complete set of checks for data frames.
7611 */
7612 gen_or(b1, b0);
7613
7614 /*
7615 * Now check for a data frame.
7616 * I.e, check "link[0] & 0x08".
7617 */
7618 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
7619 b1 = new_block(cstate, JMP(BPF_JSET));
7620 b1->s.k = 0x08;
7621 b1->stmts = s;
7622
7623 /*
7624 * AND that with the checks done for data frames.
7625 */
7626 gen_and(b1, b0);
7627
7628 /*
7629 * If the high-order bit of the type value is 0, this
7630 * is a management frame.
7631 * I.e, check "!(link[0] & 0x08)".
7632 */
7633 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
7634 b2 = new_block(cstate, JMP(BPF_JSET));
7635 b2->s.k = 0x08;
7636 b2->stmts = s;
7637 gen_not(b2);
7638
7639 /*
7640 * For management frames, the DA is at 4.
7641 */
7642 b1 = gen_mac_multicast(cstate, 4);
7643 gen_and(b2, b1);
7644
7645 /*
7646 * OR that with the checks done for data frames.
7647 * That gives the checks done for management and
7648 * data frames.
7649 */
7650 gen_or(b1, b0);
7651
7652 /*
7653 * If the low-order bit of the type value is 1,
7654 * this is either a control frame or a frame
7655 * with a reserved type, and thus not a
7656 * frame with an SA.
7657 *
7658 * I.e., check "!(link[0] & 0x04)".
7659 */
7660 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
7661 b1 = new_block(cstate, JMP(BPF_JSET));
7662 b1->s.k = 0x04;
7663 b1->stmts = s;
7664 gen_not(b1);
7665
7666 /*
7667 * AND that with the checks for data and management
7668 * frames.
7669 */
7670 gen_and(b1, b0);
7671 return b0;
7672 case DLT_IP_OVER_FC:
7673 b0 = gen_mac_multicast(cstate, 2);
7674 return b0;
7675 default:
7676 break;
7677 }
7678 /* Link not known to support multicasts */
7679 break;
7680
7681 case Q_IP:
7682 b0 = gen_linktype(cstate, ETHERTYPE_IP);
7683 b1 = gen_cmp_ge(cstate, OR_LINKPL, 16, BPF_B, (bpf_int32)224);
7684 gen_and(b0, b1);
7685 return b1;
7686
7687 case Q_IPV6:
7688 b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
7689 b1 = gen_cmp(cstate, OR_LINKPL, 24, BPF_B, (bpf_int32)255);
7690 gen_and(b0, b1);
7691 return b1;
7692 }
7693 bpf_error(cstate, "link-layer multicast filters supported only on ethernet/FDDI/token ring/ARCNET/802.11/ATM LANE/Fibre Channel");
7694 /* NOTREACHED */
7695}
7696
7697/*
7698 * Filter on inbound (dir == 0) or outbound (dir == 1) traffic.
7699 * Outbound traffic is sent by this machine, while inbound traffic is
7700 * sent by a remote machine (and may include packets destined for a
7701 * unicast or multicast link-layer address we are not subscribing to).
7702 * These are the same definitions implemented by pcap_setdirection().
7703 * Capturing only unicast traffic destined for this host is probably
7704 * better accomplished using a higher-layer filter.
7705 */
7706struct block *
7707gen_inbound(compiler_state_t *cstate, int dir)
7708{
7709 register struct block *b0;
7710
7711 /*
7712 * Only some data link types support inbound/outbound qualifiers.
7713 */
7714 switch (cstate->linktype) {
7715 case DLT_SLIP:
7716 b0 = gen_relation(cstate, BPF_JEQ,
7717 gen_load(cstate, Q_LINK, gen_loadi(cstate, 0), 1),
7718 gen_loadi(cstate, 0),
7719 dir);
7720 break;
7721
7722 case DLT_IPNET:
7723 if (dir) {
7724 /* match outgoing packets */
7725 b0 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, IPNET_OUTBOUND);
7726 } else {
7727 /* match incoming packets */
7728 b0 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, IPNET_INBOUND);
7729 }
7730 break;
7731
7732 case DLT_LINUX_SLL:
7733 /* match outgoing packets */
7734 b0 = gen_cmp(cstate, OR_LINKHDR, 0, BPF_H, LINUX_SLL_OUTGOING);
7735 if (!dir) {
7736 /* to filter on inbound traffic, invert the match */
7737 gen_not(b0);
7738 }
7739 break;
7740
7741#ifdef HAVE_NET_PFVAR_H
7742 case DLT_PFLOG:
7743 b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, dir), BPF_B,
7744 (bpf_int32)((dir == 0) ? PF_IN : PF_OUT));
7745 break;
7746#endif
7747
7748 case DLT_PPP_PPPD:
7749 if (dir) {
7750 /* match outgoing packets */
7751 b0 = gen_cmp(cstate, OR_LINKHDR, 0, BPF_B, PPP_PPPD_OUT);
7752 } else {
7753 /* match incoming packets */
7754 b0 = gen_cmp(cstate, OR_LINKHDR, 0, BPF_B, PPP_PPPD_IN);
7755 }
7756 break;
7757
7758 case DLT_JUNIPER_MFR:
7759 case DLT_JUNIPER_MLFR:
7760 case DLT_JUNIPER_MLPPP:
7761 case DLT_JUNIPER_ATM1:
7762 case DLT_JUNIPER_ATM2:
7763 case DLT_JUNIPER_PPPOE:
7764 case DLT_JUNIPER_PPPOE_ATM:
7765 case DLT_JUNIPER_GGSN:
7766 case DLT_JUNIPER_ES:
7767 case DLT_JUNIPER_MONITOR:
7768 case DLT_JUNIPER_SERVICES:
7769 case DLT_JUNIPER_ETHER:
7770 case DLT_JUNIPER_PPP:
7771 case DLT_JUNIPER_FRELAY:
7772 case DLT_JUNIPER_CHDLC:
7773 case DLT_JUNIPER_VP:
7774 case DLT_JUNIPER_ST:
7775 case DLT_JUNIPER_ISM:
7776 case DLT_JUNIPER_VS:
7777 case DLT_JUNIPER_SRX_E2E:
7778 case DLT_JUNIPER_FIBRECHANNEL:
7779 case DLT_JUNIPER_ATM_CEMIC:
7780
7781 /* juniper flags (including direction) are stored
7782 * the byte after the 3-byte magic number */
7783 if (dir) {
7784 /* match outgoing packets */
7785 b0 = gen_mcmp(cstate, OR_LINKHDR, 3, BPF_B, 0, 0x01);
7786 } else {
7787 /* match incoming packets */
7788 b0 = gen_mcmp(cstate, OR_LINKHDR, 3, BPF_B, 1, 0x01);
7789 }
7790 break;
7791
7792 default:
7793 /*
7794 * If we have packet meta-data indicating a direction,
7795 * and that metadata can be checked by BPF code, check
7796 * it. Otherwise, give up, as this link-layer type has
7797 * nothing in the packet data.
7798 *
7799 * Currently, the only platform where a BPF filter can
7800 * check that metadata is Linux with the in-kernel
7801 * BPF interpreter. If other packet capture mechanisms
7802 * and BPF filters also supported this, it would be
7803 * nice. It would be even better if they made that
7804 * metadata available so that we could provide it
7805 * with newer capture APIs, allowing it to be saved
7806 * in pcapng files.
7807 */
7808#if defined(linux) && defined(PF_PACKET) && defined(SO_ATTACH_FILTER)
7809 /*
7810 * This is Linux with PF_PACKET support.
7811 * If this is a *live* capture, we can look at
7812 * special meta-data in the filter expression;
7813 * if it's a savefile, we can't.
7814 */
7815 if (cstate->bpf_pcap->rfile != NULL) {
7816 /* We have a FILE *, so this is a savefile */
7817 bpf_error(cstate, "inbound/outbound not supported on linktype %d when reading savefiles",
7818 cstate->linktype);
7819 b0 = NULL;
7820 /* NOTREACHED */
7821 }
7822 /* match outgoing packets */
7823 b0 = gen_cmp(cstate, OR_LINKHDR, SKF_AD_OFF + SKF_AD_PKTTYPE, BPF_H,
7824 PACKET_OUTGOING);
7825 if (!dir) {
7826 /* to filter on inbound traffic, invert the match */
7827 gen_not(b0);
7828 }
7829#else /* defined(linux) && defined(PF_PACKET) && defined(SO_ATTACH_FILTER) */
7830 bpf_error(cstate, "inbound/outbound not supported on linktype %d",
7831 cstate->linktype);
7832 /* NOTREACHED */
7833#endif /* defined(linux) && defined(PF_PACKET) && defined(SO_ATTACH_FILTER) */
7834 }
7835 return (b0);
7836}
7837
7838#ifdef HAVE_NET_PFVAR_H
7839/* PF firewall log matched interface */
7840struct block *
7841gen_pf_ifname(compiler_state_t *cstate, const char *ifname)
7842{
7843 struct block *b0;
7844 u_int len, off;
7845
7846 if (cstate->linktype != DLT_PFLOG) {
7847 bpf_error(cstate, "ifname supported only on PF linktype");
7848 /* NOTREACHED */
7849 }
7850 len = sizeof(((struct pfloghdr *)0)->ifname);
7851 off = offsetof(struct pfloghdr, ifname);
7852 if (strlen(ifname) >= len) {
7853 bpf_error(cstate, "ifname interface names can only be %d characters",
7854 len-1);
7855 /* NOTREACHED */
7856 }
7857 b0 = gen_bcmp(cstate, OR_LINKHDR, off, strlen(ifname), (const u_char *)ifname);
7858 return (b0);
7859}
7860
7861/* PF firewall log ruleset name */
7862struct block *
7863gen_pf_ruleset(compiler_state_t *cstate, char *ruleset)
7864{
7865 struct block *b0;
7866
7867 if (cstate->linktype != DLT_PFLOG) {
7868 bpf_error(cstate, "ruleset supported only on PF linktype");
7869 /* NOTREACHED */
7870 }
7871
7872 if (strlen(ruleset) >= sizeof(((struct pfloghdr *)0)->ruleset)) {
7873 bpf_error(cstate, "ruleset names can only be %ld characters",
7874 (long)(sizeof(((struct pfloghdr *)0)->ruleset) - 1));
7875 /* NOTREACHED */
7876 }
7877
7878 b0 = gen_bcmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, ruleset),
7879 strlen(ruleset), (const u_char *)ruleset);
7880 return (b0);
7881}
7882
7883/* PF firewall log rule number */
7884struct block *
7885gen_pf_rnr(compiler_state_t *cstate, int rnr)
7886{
7887 struct block *b0;
7888
7889 if (cstate->linktype != DLT_PFLOG) {
7890 bpf_error(cstate, "rnr supported only on PF linktype");
7891 /* NOTREACHED */
7892 }
7893
7894 b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, rulenr), BPF_W,
7895 (bpf_int32)rnr);
7896 return (b0);
7897}
7898
7899/* PF firewall log sub-rule number */
7900struct block *
7901gen_pf_srnr(compiler_state_t *cstate, int srnr)
7902{
7903 struct block *b0;
7904
7905 if (cstate->linktype != DLT_PFLOG) {
7906 bpf_error(cstate, "srnr supported only on PF linktype");
7907 /* NOTREACHED */
7908 }
7909
7910 b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, subrulenr), BPF_W,
7911 (bpf_int32)srnr);
7912 return (b0);
7913}
7914
7915/* PF firewall log reason code */
7916struct block *
7917gen_pf_reason(compiler_state_t *cstate, int reason)
7918{
7919 struct block *b0;
7920
7921 if (cstate->linktype != DLT_PFLOG) {
7922 bpf_error(cstate, "reason supported only on PF linktype");
7923 /* NOTREACHED */
7924 }
7925
7926 b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, reason), BPF_B,
7927 (bpf_int32)reason);
7928 return (b0);
7929}
7930
7931/* PF firewall log action */
7932struct block *
7933gen_pf_action(compiler_state_t *cstate, int action)
7934{
7935 struct block *b0;
7936
7937 if (cstate->linktype != DLT_PFLOG) {
7938 bpf_error(cstate, "action supported only on PF linktype");
7939 /* NOTREACHED */
7940 }
7941
7942 b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, action), BPF_B,
7943 (bpf_int32)action);
7944 return (b0);
7945}
7946#else /* !HAVE_NET_PFVAR_H */
7947struct block *
7948gen_pf_ifname(compiler_state_t *cstate, const char *ifname _U_)
7949{
7950 bpf_error(cstate, "libpcap was compiled without pf support");
7951 /* NOTREACHED */
7952}
7953
7954struct block *
7955gen_pf_ruleset(compiler_state_t *cstate, char *ruleset _U_)
7956{
7957 bpf_error(cstate, "libpcap was compiled on a machine without pf support");
7958 /* NOTREACHED */
7959}
7960
7961struct block *
7962gen_pf_rnr(compiler_state_t *cstate, int rnr _U_)
7963{
7964 bpf_error(cstate, "libpcap was compiled on a machine without pf support");
7965 /* NOTREACHED */
7966}
7967
7968struct block *
7969gen_pf_srnr(compiler_state_t *cstate, int srnr _U_)
7970{
7971 bpf_error(cstate, "libpcap was compiled on a machine without pf support");
7972 /* NOTREACHED */
7973}
7974
7975struct block *
7976gen_pf_reason(compiler_state_t *cstate, int reason _U_)
7977{
7978 bpf_error(cstate, "libpcap was compiled on a machine without pf support");
7979 /* NOTREACHED */
7980}
7981
7982struct block *
7983gen_pf_action(compiler_state_t *cstate, int action _U_)
7984{
7985 bpf_error(cstate, "libpcap was compiled on a machine without pf support");
7986 /* NOTREACHED */
7987}
7988#endif /* HAVE_NET_PFVAR_H */
7989
7990/* IEEE 802.11 wireless header */
7991struct block *
7992gen_p80211_type(compiler_state_t *cstate, int type, int mask)
7993{
7994 struct block *b0;
7995
7996 switch (cstate->linktype) {
7997
7998 case DLT_IEEE802_11:
7999 case DLT_PRISM_HEADER:
8000 case DLT_IEEE802_11_RADIO_AVS:
8001 case DLT_IEEE802_11_RADIO:
8002 b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, (bpf_int32)type,
8003 (bpf_int32)mask);
8004 break;
8005
8006 default:
8007 bpf_error(cstate, "802.11 link-layer types supported only on 802.11");
8008 /* NOTREACHED */
8009 }
8010
8011 return (b0);
8012}
8013
8014struct block *
8015gen_p80211_fcdir(compiler_state_t *cstate, int fcdir)
8016{
8017 struct block *b0;
8018
8019 switch (cstate->linktype) {
8020
8021 case DLT_IEEE802_11:
8022 case DLT_PRISM_HEADER:
8023 case DLT_IEEE802_11_RADIO_AVS:
8024 case DLT_IEEE802_11_RADIO:
8025 break;
8026
8027 default:
8028 bpf_error(cstate, "frame direction supported only with 802.11 headers");
8029 /* NOTREACHED */
8030 }
8031
8032 b0 = gen_mcmp(cstate, OR_LINKHDR, 1, BPF_B, (bpf_int32)fcdir,
8033 (bpf_u_int32)IEEE80211_FC1_DIR_MASK);
8034
8035 return (b0);
8036}
8037
8038struct block *
8039gen_acode(compiler_state_t *cstate, const u_char *eaddr, struct qual q)
8040{
8041 switch (cstate->linktype) {
8042
8043 case DLT_ARCNET:
8044 case DLT_ARCNET_LINUX:
8045 if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) &&
8046 q.proto == Q_LINK)
8047 return (gen_ahostop(cstate, eaddr, (int)q.dir));
8048 else {
8049 bpf_error(cstate, "ARCnet address used in non-arc expression");
8050 /* NOTREACHED */
8051 }
8052 break;
8053
8054 default:
8055 bpf_error(cstate, "aid supported only on ARCnet");
8056 /* NOTREACHED */
8057 }
8058}
8059
8060static struct block *
8061gen_ahostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
8062{
8063 register struct block *b0, *b1;
8064
8065 switch (dir) {
8066 /* src comes first, different from Ethernet */
8067 case Q_SRC:
8068 return gen_bcmp(cstate, OR_LINKHDR, 0, 1, eaddr);
8069
8070 case Q_DST:
8071 return gen_bcmp(cstate, OR_LINKHDR, 1, 1, eaddr);
8072
8073 case Q_AND:
8074 b0 = gen_ahostop(cstate, eaddr, Q_SRC);
8075 b1 = gen_ahostop(cstate, eaddr, Q_DST);
8076 gen_and(b0, b1);
8077 return b1;
8078
8079 case Q_DEFAULT:
8080 case Q_OR:
8081 b0 = gen_ahostop(cstate, eaddr, Q_SRC);
8082 b1 = gen_ahostop(cstate, eaddr, Q_DST);
8083 gen_or(b0, b1);
8084 return b1;
8085
8086 case Q_ADDR1:
8087 bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11");
8088 break;
8089
8090 case Q_ADDR2:
8091 bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11");
8092 break;
8093
8094 case Q_ADDR3:
8095 bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11");
8096 break;
8097
8098 case Q_ADDR4:
8099 bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11");
8100 break;
8101
8102 case Q_RA:
8103 bpf_error(cstate, "'ra' is only supported on 802.11");
8104 break;
8105
8106 case Q_TA:
8107 bpf_error(cstate, "'ta' is only supported on 802.11");
8108 break;
8109 }
8110 abort();
8111 /* NOTREACHED */
8112}
8113
8114static struct block *
8115gen_vlan_tpid_test(compiler_state_t *cstate)
8116{
8117 struct block *b0, *b1;
8118
8119 /* check for VLAN, including QinQ */
8120 b0 = gen_linktype(cstate, ETHERTYPE_8021Q);
8121 b1 = gen_linktype(cstate, ETHERTYPE_8021AD);
8122 gen_or(b0,b1);
8123 b0 = b1;
8124 b1 = gen_linktype(cstate, ETHERTYPE_8021QINQ);
8125 gen_or(b0,b1);
8126
8127 return b1;
8128}
8129
8130static struct block *
8131gen_vlan_vid_test(compiler_state_t *cstate, int vlan_num)
8132{
8133 return gen_mcmp(cstate, OR_LINKPL, 0, BPF_H, (bpf_int32)vlan_num, 0x0fff);
8134}
8135
8136static struct block *
8137gen_vlan_no_bpf_extensions(compiler_state_t *cstate, int vlan_num)
8138{
8139 struct block *b0, *b1;
8140
8141 b0 = gen_vlan_tpid_test(cstate);
8142
8143 if (vlan_num >= 0) {
8144 b1 = gen_vlan_vid_test(cstate, vlan_num);
8145 gen_and(b0, b1);
8146 b0 = b1;
8147 }
8148
8149 /*
8150 * Both payload and link header type follow the VLAN tags so that
8151 * both need to be updated.
8152 */
8153 cstate->off_linkpl.constant_part += 4;
8154 cstate->off_linktype.constant_part += 4;
8155
8156 return b0;
8157}
8158
8159#if defined(SKF_AD_VLAN_TAG_PRESENT)
8160/* add v to variable part of off */
8161static void
8162gen_vlan_vloffset_add(compiler_state_t *cstate, bpf_abs_offset *off, int v, struct slist *s)
8163{
8164 struct slist *s2;
8165
8166 if (!off->is_variable)
8167 off->is_variable = 1;
8168 if (off->reg == -1)
8169 off->reg = alloc_reg(cstate);
8170
8171 s2 = new_stmt(cstate, BPF_LD|BPF_MEM);
8172 s2->s.k = off->reg;
8173 sappend(s, s2);
8174 s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_IMM);
8175 s2->s.k = v;
8176 sappend(s, s2);
8177 s2 = new_stmt(cstate, BPF_ST);
8178 s2->s.k = off->reg;
8179 sappend(s, s2);
8180}
8181
8182/*
8183 * patch block b_tpid (VLAN TPID test) to update variable parts of link payload
8184 * and link type offsets first
8185 */
8186static void
8187gen_vlan_patch_tpid_test(compiler_state_t *cstate, struct block *b_tpid)
8188{
8189 struct slist s;
8190
8191 /* offset determined at run time, shift variable part */
8192 s.next = NULL;
8193 cstate->is_vlan_vloffset = 1;
8194 gen_vlan_vloffset_add(cstate, &cstate->off_linkpl, 4, &s);
8195 gen_vlan_vloffset_add(cstate, &cstate->off_linktype, 4, &s);
8196
8197 /* we get a pointer to a chain of or-ed blocks, patch first of them */
8198 sappend(s.next, b_tpid->head->stmts);
8199 b_tpid->head->stmts = s.next;
8200}
8201
8202/*
8203 * patch block b_vid (VLAN id test) to load VID value either from packet
8204 * metadata (using BPF extensions) if SKF_AD_VLAN_TAG_PRESENT is true
8205 */
8206static void
8207gen_vlan_patch_vid_test(compiler_state_t *cstate, struct block *b_vid)
8208{
8209 struct slist *s, *s2, *sjeq;
8210 unsigned cnt;
8211
8212 s = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
8213 s->s.k = SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT;
8214
8215 /* true -> next instructions, false -> beginning of b_vid */
8216 sjeq = new_stmt(cstate, JMP(BPF_JEQ));
8217 sjeq->s.k = 1;
8218 sjeq->s.jf = b_vid->stmts;
8219 sappend(s, sjeq);
8220
8221 s2 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
8222 s2->s.k = SKF_AD_OFF + SKF_AD_VLAN_TAG;
8223 sappend(s, s2);
8224 sjeq->s.jt = s2;
8225
8226 /* jump to the test in b_vid (bypass loading VID from packet data) */
8227 cnt = 0;
8228 for (s2 = b_vid->stmts; s2; s2 = s2->next)
8229 cnt++;
8230 s2 = new_stmt(cstate, JMP(BPF_JA));
8231 s2->s.k = cnt;
8232 sappend(s, s2);
8233
8234 /* insert our statements at the beginning of b_vid */
8235 sappend(s, b_vid->stmts);
8236 b_vid->stmts = s;
8237}
8238
8239/*
8240 * Generate check for "vlan" or "vlan <id>" on systems with support for BPF
8241 * extensions. Even if kernel supports VLAN BPF extensions, (outermost) VLAN
8242 * tag can be either in metadata or in packet data; therefore if the
8243 * SKF_AD_VLAN_TAG_PRESENT test is negative, we need to check link
8244 * header for VLAN tag. As the decision is done at run time, we need
8245 * update variable part of the offsets
8246 */
8247static struct block *
8248gen_vlan_bpf_extensions(compiler_state_t *cstate, int vlan_num)
8249{
8250 struct block *b0, *b_tpid, *b_vid = NULL;
8251 struct slist *s;
8252
8253 /* generate new filter code based on extracting packet
8254 * metadata */
8255 s = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
8256 s->s.k = SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT;
8257
8258 b0 = new_block(cstate, JMP(BPF_JEQ));
8259 b0->stmts = s;
8260 b0->s.k = 1;
8261
8262 /*
8263 * This is tricky. We need to insert the statements updating variable
8264 * parts of offsets before the the traditional TPID and VID tests so
8265 * that they are called whenever SKF_AD_VLAN_TAG_PRESENT fails but
8266 * we do not want this update to affect those checks. That's why we
8267 * generate both test blocks first and insert the statements updating
8268 * variable parts of both offsets after that. This wouldn't work if
8269 * there already were variable length link header when entering this
8270 * function but gen_vlan_bpf_extensions() isn't called in that case.
8271 */
8272 b_tpid = gen_vlan_tpid_test(cstate);
8273 if (vlan_num >= 0)
8274 b_vid = gen_vlan_vid_test(cstate, vlan_num);
8275
8276 gen_vlan_patch_tpid_test(cstate, b_tpid);
8277 gen_or(b0, b_tpid);
8278 b0 = b_tpid;
8279
8280 if (vlan_num >= 0) {
8281 gen_vlan_patch_vid_test(cstate, b_vid);
8282 gen_and(b0, b_vid);
8283 b0 = b_vid;
8284 }
8285
8286 return b0;
8287}
8288#endif
8289
8290/*
8291 * support IEEE 802.1Q VLAN trunk over ethernet
8292 */
8293struct block *
8294gen_vlan(compiler_state_t *cstate, int vlan_num)
8295{
8296 struct block *b0;
8297
8298 /* can't check for VLAN-encapsulated packets inside MPLS */
8299 if (cstate->label_stack_depth > 0)
8300 bpf_error(cstate, "no VLAN match after MPLS");
8301
8302 /*
8303 * Check for a VLAN packet, and then change the offsets to point
8304 * to the type and data fields within the VLAN packet. Just
8305 * increment the offsets, so that we can support a hierarchy, e.g.
8306 * "vlan 300 && vlan 200" to capture VLAN 200 encapsulated within
8307 * VLAN 100.
8308 *
8309 * XXX - this is a bit of a kludge. If we were to split the
8310 * compiler into a parser that parses an expression and
8311 * generates an expression tree, and a code generator that
8312 * takes an expression tree (which could come from our
8313 * parser or from some other parser) and generates BPF code,
8314 * we could perhaps make the offsets parameters of routines
8315 * and, in the handler for an "AND" node, pass to subnodes
8316 * other than the VLAN node the adjusted offsets.
8317 *
8318 * This would mean that "vlan" would, instead of changing the
8319 * behavior of *all* tests after it, change only the behavior
8320 * of tests ANDed with it. That would change the documented
8321 * semantics of "vlan", which might break some expressions.
8322 * However, it would mean that "(vlan and ip) or ip" would check
8323 * both for VLAN-encapsulated IP and IP-over-Ethernet, rather than
8324 * checking only for VLAN-encapsulated IP, so that could still
8325 * be considered worth doing; it wouldn't break expressions
8326 * that are of the form "vlan and ..." or "vlan N and ...",
8327 * which I suspect are the most common expressions involving
8328 * "vlan". "vlan or ..." doesn't necessarily do what the user
8329 * would really want, now, as all the "or ..." tests would
8330 * be done assuming a VLAN, even though the "or" could be viewed
8331 * as meaning "or, if this isn't a VLAN packet...".
8332 */
8333 switch (cstate->linktype) {
8334
8335 case DLT_EN10MB:
8336 case DLT_NETANALYZER:
8337 case DLT_NETANALYZER_TRANSPARENT:
8338#if defined(SKF_AD_VLAN_TAG_PRESENT)
8339 /* Verify that this is the outer part of the packet and
8340 * not encapsulated somehow. */
8341 if (cstate->vlan_stack_depth == 0 && !cstate->off_linkhdr.is_variable &&
8342 cstate->off_linkhdr.constant_part ==
8343 cstate->off_outermostlinkhdr.constant_part) {
8344 /*
8345 * Do we need special VLAN handling?
8346 */
8347 if (cstate->bpf_pcap->bpf_codegen_flags & BPF_SPECIAL_VLAN_HANDLING)
8348 b0 = gen_vlan_bpf_extensions(cstate, vlan_num);
8349 else
8350 b0 = gen_vlan_no_bpf_extensions(cstate, vlan_num);
8351 } else
8352#endif
8353 b0 = gen_vlan_no_bpf_extensions(cstate, vlan_num);
8354 break;
8355
8356 case DLT_IEEE802_11:
8357 case DLT_PRISM_HEADER:
8358 case DLT_IEEE802_11_RADIO_AVS:
8359 case DLT_IEEE802_11_RADIO:
8360 b0 = gen_vlan_no_bpf_extensions(cstate, vlan_num);
8361 break;
8362
8363 default:
8364 bpf_error(cstate, "no VLAN support for data link type %d",
8365 cstate->linktype);
8366 /*NOTREACHED*/
8367 }
8368
8369 cstate->vlan_stack_depth++;
8370
8371 return (b0);
8372}
8373
8374/*
8375 * support for MPLS
8376 */
8377struct block *
8378gen_mpls(compiler_state_t *cstate, int label_num)
8379{
8380 struct block *b0, *b1;
8381
8382 if (cstate->label_stack_depth > 0) {
8383 /* just match the bottom-of-stack bit clear */
8384 b0 = gen_mcmp(cstate, OR_PREVMPLSHDR, 2, BPF_B, 0, 0x01);
8385 } else {
8386 /*
8387 * We're not in an MPLS stack yet, so check the link-layer
8388 * type against MPLS.
8389 */
8390 switch (cstate->linktype) {
8391
8392 case DLT_C_HDLC: /* fall through */
8393 case DLT_EN10MB:
8394 case DLT_NETANALYZER:
8395 case DLT_NETANALYZER_TRANSPARENT:
8396 b0 = gen_linktype(cstate, ETHERTYPE_MPLS);
8397 break;
8398
8399 case DLT_PPP:
8400 b0 = gen_linktype(cstate, PPP_MPLS_UCAST);
8401 break;
8402
8403 /* FIXME add other DLT_s ...
8404 * for Frame-Relay/and ATM this may get messy due to SNAP headers
8405 * leave it for now */
8406
8407 default:
8408 bpf_error(cstate, "no MPLS support for data link type %d",
8409 cstate->linktype);
8410 /*NOTREACHED*/
8411 break;
8412 }
8413 }
8414
8415 /* If a specific MPLS label is requested, check it */
8416 if (label_num >= 0) {
8417 label_num = label_num << 12; /* label is shifted 12 bits on the wire */
8418 b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_W, (bpf_int32)label_num,
8419 0xfffff000); /* only compare the first 20 bits */
8420 gen_and(b0, b1);
8421 b0 = b1;
8422 }
8423
8424 /*
8425 * Change the offsets to point to the type and data fields within
8426 * the MPLS packet. Just increment the offsets, so that we
8427 * can support a hierarchy, e.g. "mpls 100000 && mpls 1024" to
8428 * capture packets with an outer label of 100000 and an inner
8429 * label of 1024.
8430 *
8431 * Increment the MPLS stack depth as well; this indicates that
8432 * we're checking MPLS-encapsulated headers, to make sure higher
8433 * level code generators don't try to match against IP-related
8434 * protocols such as Q_ARP, Q_RARP etc.
8435 *
8436 * XXX - this is a bit of a kludge. See comments in gen_vlan().
8437 */
8438 cstate->off_nl_nosnap += 4;
8439 cstate->off_nl += 4;
8440 cstate->label_stack_depth++;
8441 return (b0);
8442}
8443
8444/*
8445 * Support PPPOE discovery and session.
8446 */
8447struct block *
8448gen_pppoed(compiler_state_t *cstate)
8449{
8450 /* check for PPPoE discovery */
8451 return gen_linktype(cstate, (bpf_int32)ETHERTYPE_PPPOED);
8452}
8453
8454struct block *
8455gen_pppoes(compiler_state_t *cstate, int sess_num)
8456{
8457 struct block *b0, *b1;
8458
8459 /*
8460 * Test against the PPPoE session link-layer type.
8461 */
8462 b0 = gen_linktype(cstate, (bpf_int32)ETHERTYPE_PPPOES);
8463
8464 /* If a specific session is requested, check PPPoE session id */
8465 if (sess_num >= 0) {
8466 b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_W,
8467 (bpf_int32)sess_num, 0x0000ffff);
8468 gen_and(b0, b1);
8469 b0 = b1;
8470 }
8471
8472 /*
8473 * Change the offsets to point to the type and data fields within
8474 * the PPP packet, and note that this is PPPoE rather than
8475 * raw PPP.
8476 *
8477 * XXX - this is a bit of a kludge. If we were to split the
8478 * compiler into a parser that parses an expression and
8479 * generates an expression tree, and a code generator that
8480 * takes an expression tree (which could come from our
8481 * parser or from some other parser) and generates BPF code,
8482 * we could perhaps make the offsets parameters of routines
8483 * and, in the handler for an "AND" node, pass to subnodes
8484 * other than the PPPoE node the adjusted offsets.
8485 *
8486 * This would mean that "pppoes" would, instead of changing the
8487 * behavior of *all* tests after it, change only the behavior
8488 * of tests ANDed with it. That would change the documented
8489 * semantics of "pppoes", which might break some expressions.
8490 * However, it would mean that "(pppoes and ip) or ip" would check
8491 * both for VLAN-encapsulated IP and IP-over-Ethernet, rather than
8492 * checking only for VLAN-encapsulated IP, so that could still
8493 * be considered worth doing; it wouldn't break expressions
8494 * that are of the form "pppoes and ..." which I suspect are the
8495 * most common expressions involving "pppoes". "pppoes or ..."
8496 * doesn't necessarily do what the user would really want, now,
8497 * as all the "or ..." tests would be done assuming PPPoE, even
8498 * though the "or" could be viewed as meaning "or, if this isn't
8499 * a PPPoE packet...".
8500 *
8501 * The "network-layer" protocol is PPPoE, which has a 6-byte
8502 * PPPoE header, followed by a PPP packet.
8503 *
8504 * There is no HDLC encapsulation for the PPP packet (it's
8505 * encapsulated in PPPoES instead), so the link-layer type
8506 * starts at the first byte of the PPP packet. For PPPoE,
8507 * that offset is relative to the beginning of the total
8508 * link-layer payload, including any 802.2 LLC header, so
8509 * it's 6 bytes past cstate->off_nl.
8510 */
8511 PUSH_LINKHDR(cstate, DLT_PPP, cstate->off_linkpl.is_variable,
8512 cstate->off_linkpl.constant_part + cstate->off_nl + 6, /* 6 bytes past the PPPoE header */
8513 cstate->off_linkpl.reg);
8514
8515 cstate->off_linktype = cstate->off_linkhdr;
8516 cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 2;
8517
8518 cstate->off_nl = 0;
8519 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
8520
8521 return b0;
8522}
8523
8524/* Check that this is Geneve and the VNI is correct if
8525 * specified. Parameterized to handle both IPv4 and IPv6. */
8526static struct block *
8527gen_geneve_check(compiler_state_t *cstate,
8528 struct block *(*gen_portfn)(compiler_state_t *, int, int, int),
8529 enum e_offrel offrel, int vni)
8530{
8531 struct block *b0, *b1;
8532
8533 b0 = gen_portfn(cstate, GENEVE_PORT, IPPROTO_UDP, Q_DST);
8534
8535 /* Check that we are operating on version 0. Otherwise, we
8536 * can't decode the rest of the fields. The version is 2 bits
8537 * in the first byte of the Geneve header. */
8538 b1 = gen_mcmp(cstate, offrel, 8, BPF_B, (bpf_int32)0, 0xc0);
8539 gen_and(b0, b1);
8540 b0 = b1;
8541
8542 if (vni >= 0) {
8543 vni <<= 8; /* VNI is in the upper 3 bytes */
8544 b1 = gen_mcmp(cstate, offrel, 12, BPF_W, (bpf_int32)vni,
8545 0xffffff00);
8546 gen_and(b0, b1);
8547 b0 = b1;
8548 }
8549
8550 return b0;
8551}
8552
8553/* The IPv4 and IPv6 Geneve checks need to do two things:
8554 * - Verify that this actually is Geneve with the right VNI.
8555 * - Place the IP header length (plus variable link prefix if
8556 * needed) into register A to be used later to compute
8557 * the inner packet offsets. */
8558static struct block *
8559gen_geneve4(compiler_state_t *cstate, int vni)
8560{
8561 struct block *b0, *b1;
8562 struct slist *s, *s1;
8563
8564 b0 = gen_geneve_check(cstate, gen_port, OR_TRAN_IPV4, vni);
8565
8566 /* Load the IP header length into A. */
8567 s = gen_loadx_iphdrlen(cstate);
8568
8569 s1 = new_stmt(cstate, BPF_MISC|BPF_TXA);
8570 sappend(s, s1);
8571
8572 /* Forcibly append these statements to the true condition
8573 * of the protocol check by creating a new block that is
8574 * always true and ANDing them. */
8575 b1 = new_block(cstate, BPF_JMP|BPF_JEQ|BPF_X);
8576 b1->stmts = s;
8577 b1->s.k = 0;
8578
8579 gen_and(b0, b1);
8580
8581 return b1;
8582}
8583
8584static struct block *
8585gen_geneve6(compiler_state_t *cstate, int vni)
8586{
8587 struct block *b0, *b1;
8588 struct slist *s, *s1;
8589
8590 b0 = gen_geneve_check(cstate, gen_port6, OR_TRAN_IPV6, vni);
8591
8592 /* Load the IP header length. We need to account for a
8593 * variable length link prefix if there is one. */
8594 s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl);
8595 if (s) {
8596 s1 = new_stmt(cstate, BPF_LD|BPF_IMM);
8597 s1->s.k = 40;
8598 sappend(s, s1);
8599
8600 s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X);
8601 s1->s.k = 0;
8602 sappend(s, s1);
8603 } else {
8604 s = new_stmt(cstate, BPF_LD|BPF_IMM);
8605 s->s.k = 40;
8606 }
8607
8608 /* Forcibly append these statements to the true condition
8609 * of the protocol check by creating a new block that is
8610 * always true and ANDing them. */
8611 s1 = new_stmt(cstate, BPF_MISC|BPF_TAX);
8612 sappend(s, s1);
8613
8614 b1 = new_block(cstate, BPF_JMP|BPF_JEQ|BPF_X);
8615 b1->stmts = s;
8616 b1->s.k = 0;
8617
8618 gen_and(b0, b1);
8619
8620 return b1;
8621}
8622
8623/* We need to store three values based on the Geneve header::
8624 * - The offset of the linktype.
8625 * - The offset of the end of the Geneve header.
8626 * - The offset of the end of the encapsulated MAC header. */
8627static struct slist *
8628gen_geneve_offsets(compiler_state_t *cstate)
8629{
8630 struct slist *s, *s1, *s_proto;
8631
8632 /* First we need to calculate the offset of the Geneve header
8633 * itself. This is composed of the IP header previously calculated
8634 * (include any variable link prefix) and stored in A plus the
8635 * fixed sized headers (fixed link prefix, MAC length, and UDP
8636 * header). */
8637 s = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
8638 s->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 8;
8639
8640 /* Stash this in X since we'll need it later. */
8641 s1 = new_stmt(cstate, BPF_MISC|BPF_TAX);
8642 sappend(s, s1);
8643
8644 /* The EtherType in Geneve is 2 bytes in. Calculate this and
8645 * store it. */
8646 s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
8647 s1->s.k = 2;
8648 sappend(s, s1);
8649
8650 cstate->off_linktype.reg = alloc_reg(cstate);
8651 cstate->off_linktype.is_variable = 1;
8652 cstate->off_linktype.constant_part = 0;
8653
8654 s1 = new_stmt(cstate, BPF_ST);
8655 s1->s.k = cstate->off_linktype.reg;
8656 sappend(s, s1);
8657
8658 /* Load the Geneve option length and mask and shift to get the
8659 * number of bytes. It is stored in the first byte of the Geneve
8660 * header. */
8661 s1 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
8662 s1->s.k = 0;
8663 sappend(s, s1);
8664
8665 s1 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
8666 s1->s.k = 0x3f;
8667 sappend(s, s1);
8668
8669 s1 = new_stmt(cstate, BPF_ALU|BPF_MUL|BPF_K);
8670 s1->s.k = 4;
8671 sappend(s, s1);
8672
8673 /* Add in the rest of the Geneve base header. */
8674 s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
8675 s1->s.k = 8;
8676 sappend(s, s1);
8677
8678 /* Add the Geneve header length to its offset and store. */
8679 s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X);
8680 s1->s.k = 0;
8681 sappend(s, s1);
8682
8683 /* Set the encapsulated type as Ethernet. Even though we may
8684 * not actually have Ethernet inside there are two reasons this
8685 * is useful:
8686 * - The linktype field is always in EtherType format regardless
8687 * of whether it is in Geneve or an inner Ethernet frame.
8688 * - The only link layer that we have specific support for is
8689 * Ethernet. We will confirm that the packet actually is
8690 * Ethernet at runtime before executing these checks. */
8691 PUSH_LINKHDR(cstate, DLT_EN10MB, 1, 0, alloc_reg(cstate));
8692
8693 s1 = new_stmt(cstate, BPF_ST);
8694 s1->s.k = cstate->off_linkhdr.reg;
8695 sappend(s, s1);
8696
8697 /* Calculate whether we have an Ethernet header or just raw IP/
8698 * MPLS/etc. If we have Ethernet, advance the end of the MAC offset
8699 * and linktype by 14 bytes so that the network header can be found
8700 * seamlessly. Otherwise, keep what we've calculated already. */
8701
8702 /* We have a bare jmp so we can't use the optimizer. */
8703 cstate->no_optimize = 1;
8704
8705 /* Load the EtherType in the Geneve header, 2 bytes in. */
8706 s1 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_H);
8707 s1->s.k = 2;
8708 sappend(s, s1);
8709
8710 /* Load X with the end of the Geneve header. */
8711 s1 = new_stmt(cstate, BPF_LDX|BPF_MEM);
8712 s1->s.k = cstate->off_linkhdr.reg;
8713 sappend(s, s1);
8714
8715 /* Check if the EtherType is Transparent Ethernet Bridging. At the
8716 * end of this check, we should have the total length in X. In
8717 * the non-Ethernet case, it's already there. */
8718 s_proto = new_stmt(cstate, JMP(BPF_JEQ));
8719 s_proto->s.k = ETHERTYPE_TEB;
8720 sappend(s, s_proto);
8721
8722 s1 = new_stmt(cstate, BPF_MISC|BPF_TXA);
8723 sappend(s, s1);
8724 s_proto->s.jt = s1;
8725
8726 /* Since this is Ethernet, use the EtherType of the payload
8727 * directly as the linktype. Overwrite what we already have. */
8728 s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
8729 s1->s.k = 12;
8730 sappend(s, s1);
8731
8732 s1 = new_stmt(cstate, BPF_ST);
8733 s1->s.k = cstate->off_linktype.reg;
8734 sappend(s, s1);
8735
8736 /* Advance two bytes further to get the end of the Ethernet
8737 * header. */
8738 s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
8739 s1->s.k = 2;
8740 sappend(s, s1);
8741
8742 /* Move the result to X. */
8743 s1 = new_stmt(cstate, BPF_MISC|BPF_TAX);
8744 sappend(s, s1);
8745
8746 /* Store the final result of our linkpl calculation. */
8747 cstate->off_linkpl.reg = alloc_reg(cstate);
8748 cstate->off_linkpl.is_variable = 1;
8749 cstate->off_linkpl.constant_part = 0;
8750
8751 s1 = new_stmt(cstate, BPF_STX);
8752 s1->s.k = cstate->off_linkpl.reg;
8753 sappend(s, s1);
8754 s_proto->s.jf = s1;
8755
8756 cstate->off_nl = 0;
8757
8758 return s;
8759}
8760
8761/* Check to see if this is a Geneve packet. */
8762struct block *
8763gen_geneve(compiler_state_t *cstate, int vni)
8764{
8765 struct block *b0, *b1;
8766 struct slist *s;
8767
8768 b0 = gen_geneve4(cstate, vni);
8769 b1 = gen_geneve6(cstate, vni);
8770
8771 gen_or(b0, b1);
8772 b0 = b1;
8773
8774 /* Later filters should act on the payload of the Geneve frame,
8775 * update all of the header pointers. Attach this code so that
8776 * it gets executed in the event that the Geneve filter matches. */
8777 s = gen_geneve_offsets(cstate);
8778
8779 b1 = gen_true(cstate);
8780 sappend(s, b1->stmts);
8781 b1->stmts = s;
8782
8783 gen_and(b0, b1);
8784
8785 cstate->is_geneve = 1;
8786
8787 return b1;
8788}
8789
8790/* Check that the encapsulated frame has a link layer header
8791 * for Ethernet filters. */
8792static struct block *
8793gen_geneve_ll_check(compiler_state_t *cstate)
8794{
8795 struct block *b0;
8796 struct slist *s, *s1;
8797
8798 /* The easiest way to see if there is a link layer present
8799 * is to check if the link layer header and payload are not
8800 * the same. */
8801
8802 /* Geneve always generates pure variable offsets so we can
8803 * compare only the registers. */
8804 s = new_stmt(cstate, BPF_LD|BPF_MEM);
8805 s->s.k = cstate->off_linkhdr.reg;
8806
8807 s1 = new_stmt(cstate, BPF_LDX|BPF_MEM);
8808 s1->s.k = cstate->off_linkpl.reg;
8809 sappend(s, s1);
8810
8811 b0 = new_block(cstate, BPF_JMP|BPF_JEQ|BPF_X);
8812 b0->stmts = s;
8813 b0->s.k = 0;
8814 gen_not(b0);
8815
8816 return b0;
8817}
8818
8819struct block *
8820gen_atmfield_code(compiler_state_t *cstate, int atmfield, bpf_int32 jvalue,
8821 bpf_u_int32 jtype, int reverse)
8822{
8823 struct block *b0;
8824
8825 switch (atmfield) {
8826
8827 case A_VPI:
8828 if (!cstate->is_atm)
8829 bpf_error(cstate, "'vpi' supported only on raw ATM");
8830 if (cstate->off_vpi == OFFSET_NOT_SET)
8831 abort();
8832 b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_vpi, BPF_B, 0xffffffff, jtype,
8833 reverse, jvalue);
8834 break;
8835
8836 case A_VCI:
8837 if (!cstate->is_atm)
8838 bpf_error(cstate, "'vci' supported only on raw ATM");
8839 if (cstate->off_vci == OFFSET_NOT_SET)
8840 abort();
8841 b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_vci, BPF_H, 0xffffffff, jtype,
8842 reverse, jvalue);
8843 break;
8844
8845 case A_PROTOTYPE:
8846 if (cstate->off_proto == OFFSET_NOT_SET)
8847 abort(); /* XXX - this isn't on FreeBSD */
8848 b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_proto, BPF_B, 0x0f, jtype,
8849 reverse, jvalue);
8850 break;
8851
8852 case A_MSGTYPE:
8853 if (cstate->off_payload == OFFSET_NOT_SET)
8854 abort();
8855 b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_payload + MSG_TYPE_POS, BPF_B,
8856 0xffffffff, jtype, reverse, jvalue);
8857 break;
8858
8859 case A_CALLREFTYPE:
8860 if (!cstate->is_atm)
8861 bpf_error(cstate, "'callref' supported only on raw ATM");
8862 if (cstate->off_proto == OFFSET_NOT_SET)
8863 abort();
8864 b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_proto, BPF_B, 0xffffffff,
8865 jtype, reverse, jvalue);
8866 break;
8867
8868 default:
8869 abort();
8870 }
8871 return b0;
8872}
8873
8874struct block *
8875gen_atmtype_abbrev(compiler_state_t *cstate, int type)
8876{
8877 struct block *b0, *b1;
8878
8879 switch (type) {
8880
8881 case A_METAC:
8882 /* Get all packets in Meta signalling Circuit */
8883 if (!cstate->is_atm)
8884 bpf_error(cstate, "'metac' supported only on raw ATM");
8885 b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
8886 b1 = gen_atmfield_code(cstate, A_VCI, 1, BPF_JEQ, 0);
8887 gen_and(b0, b1);
8888 break;
8889
8890 case A_BCC:
8891 /* Get all packets in Broadcast Circuit*/
8892 if (!cstate->is_atm)
8893 bpf_error(cstate, "'bcc' supported only on raw ATM");
8894 b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
8895 b1 = gen_atmfield_code(cstate, A_VCI, 2, BPF_JEQ, 0);
8896 gen_and(b0, b1);
8897 break;
8898
8899 case A_OAMF4SC:
8900 /* Get all cells in Segment OAM F4 circuit*/
8901 if (!cstate->is_atm)
8902 bpf_error(cstate, "'oam4sc' supported only on raw ATM");
8903 b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
8904 b1 = gen_atmfield_code(cstate, A_VCI, 3, BPF_JEQ, 0);
8905 gen_and(b0, b1);
8906 break;
8907
8908 case A_OAMF4EC:
8909 /* Get all cells in End-to-End OAM F4 Circuit*/
8910 if (!cstate->is_atm)
8911 bpf_error(cstate, "'oam4ec' supported only on raw ATM");
8912 b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
8913 b1 = gen_atmfield_code(cstate, A_VCI, 4, BPF_JEQ, 0);
8914 gen_and(b0, b1);
8915 break;
8916
8917 case A_SC:
8918 /* Get all packets in connection Signalling Circuit */
8919 if (!cstate->is_atm)
8920 bpf_error(cstate, "'sc' supported only on raw ATM");
8921 b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
8922 b1 = gen_atmfield_code(cstate, A_VCI, 5, BPF_JEQ, 0);
8923 gen_and(b0, b1);
8924 break;
8925
8926 case A_ILMIC:
8927 /* Get all packets in ILMI Circuit */
8928 if (!cstate->is_atm)
8929 bpf_error(cstate, "'ilmic' supported only on raw ATM");
8930 b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
8931 b1 = gen_atmfield_code(cstate, A_VCI, 16, BPF_JEQ, 0);
8932 gen_and(b0, b1);
8933 break;
8934
8935 case A_LANE:
8936 /* Get all LANE packets */
8937 if (!cstate->is_atm)
8938 bpf_error(cstate, "'lane' supported only on raw ATM");
8939 b1 = gen_atmfield_code(cstate, A_PROTOTYPE, PT_LANE, BPF_JEQ, 0);
8940
8941 /*
8942 * Arrange that all subsequent tests assume LANE
8943 * rather than LLC-encapsulated packets, and set
8944 * the offsets appropriately for LANE-encapsulated
8945 * Ethernet.
8946 *
8947 * We assume LANE means Ethernet, not Token Ring.
8948 */
8949 PUSH_LINKHDR(cstate, DLT_EN10MB, 0,
8950 cstate->off_payload + 2, /* Ethernet header */
8951 -1);
8952 cstate->off_linktype.constant_part = cstate->off_linkhdr.constant_part + 12;
8953 cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 14; /* Ethernet */
8954 cstate->off_nl = 0; /* Ethernet II */
8955 cstate->off_nl_nosnap = 3; /* 802.3+802.2 */
8956 break;
8957
8958 case A_LLC:
8959 /* Get all LLC-encapsulated packets */
8960 if (!cstate->is_atm)
8961 bpf_error(cstate, "'llc' supported only on raw ATM");
8962 b1 = gen_atmfield_code(cstate, A_PROTOTYPE, PT_LLC, BPF_JEQ, 0);
8963 cstate->linktype = cstate->prevlinktype;
8964 break;
8965
8966 default:
8967 abort();
8968 }
8969 return b1;
8970}
8971
8972/*
8973 * Filtering for MTP2 messages based on li value
8974 * FISU, length is null
8975 * LSSU, length is 1 or 2
8976 * MSU, length is 3 or more
8977 * For MTP2_HSL, sequences are on 2 bytes, and length on 9 bits
8978 */
8979struct block *
8980gen_mtp2type_abbrev(compiler_state_t *cstate, int type)
8981{
8982 struct block *b0, *b1;
8983
8984 switch (type) {
8985
8986 case M_FISU:
8987 if ( (cstate->linktype != DLT_MTP2) &&
8988 (cstate->linktype != DLT_ERF) &&
8989 (cstate->linktype != DLT_MTP2_WITH_PHDR) )
8990 bpf_error(cstate, "'fisu' supported only on MTP2");
8991 /* gen_ncmp(cstate, offrel, offset, size, mask, jtype, reverse, value) */
8992 b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3f, BPF_JEQ, 0, 0);
8993 break;
8994
8995 case M_LSSU:
8996 if ( (cstate->linktype != DLT_MTP2) &&
8997 (cstate->linktype != DLT_ERF) &&
8998 (cstate->linktype != DLT_MTP2_WITH_PHDR) )
8999 bpf_error(cstate, "'lssu' supported only on MTP2");
9000 b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3f, BPF_JGT, 1, 2);
9001 b1 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3f, BPF_JGT, 0, 0);
9002 gen_and(b1, b0);
9003 break;
9004
9005 case M_MSU:
9006 if ( (cstate->linktype != DLT_MTP2) &&
9007 (cstate->linktype != DLT_ERF) &&
9008 (cstate->linktype != DLT_MTP2_WITH_PHDR) )
9009 bpf_error(cstate, "'msu' supported only on MTP2");
9010 b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3f, BPF_JGT, 0, 2);
9011 break;
9012
9013 case MH_FISU:
9014 if ( (cstate->linktype != DLT_MTP2) &&
9015 (cstate->linktype != DLT_ERF) &&
9016 (cstate->linktype != DLT_MTP2_WITH_PHDR) )
9017 bpf_error(cstate, "'hfisu' supported only on MTP2_HSL");
9018 /* gen_ncmp(cstate, offrel, offset, size, mask, jtype, reverse, value) */
9019 b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80, BPF_JEQ, 0, 0);
9020 break;
9021
9022 case MH_LSSU:
9023 if ( (cstate->linktype != DLT_MTP2) &&
9024 (cstate->linktype != DLT_ERF) &&
9025 (cstate->linktype != DLT_MTP2_WITH_PHDR) )
9026 bpf_error(cstate, "'hlssu' supported only on MTP2_HSL");
9027 b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80, BPF_JGT, 1, 0x0100);
9028 b1 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80, BPF_JGT, 0, 0);
9029 gen_and(b1, b0);
9030 break;
9031
9032 case MH_MSU:
9033 if ( (cstate->linktype != DLT_MTP2) &&
9034 (cstate->linktype != DLT_ERF) &&
9035 (cstate->linktype != DLT_MTP2_WITH_PHDR) )
9036 bpf_error(cstate, "'hmsu' supported only on MTP2_HSL");
9037 b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80, BPF_JGT, 0, 0x0100);
9038 break;
9039
9040 default:
9041 abort();
9042 }
9043 return b0;
9044}
9045
9046struct block *
9047gen_mtp3field_code(compiler_state_t *cstate, int mtp3field, bpf_u_int32 jvalue,
9048 bpf_u_int32 jtype, int reverse)
9049{
9050 struct block *b0;
9051 bpf_u_int32 val1 , val2 , val3;
9052 u_int newoff_sio = cstate->off_sio;
9053 u_int newoff_opc = cstate->off_opc;
9054 u_int newoff_dpc = cstate->off_dpc;
9055 u_int newoff_sls = cstate->off_sls;
9056
9057 switch (mtp3field) {
9058
9059 case MH_SIO:
9060 newoff_sio += 3; /* offset for MTP2_HSL */
9061 /* FALLTHROUGH */
9062
9063 case M_SIO:
9064 if (cstate->off_sio == OFFSET_NOT_SET)
9065 bpf_error(cstate, "'sio' supported only on SS7");
9066 /* sio coded on 1 byte so max value 255 */
9067 if(jvalue > 255)
9068 bpf_error(cstate, "sio value %u too big; max value = 255",
9069 jvalue);
9070 b0 = gen_ncmp(cstate, OR_PACKET, newoff_sio, BPF_B, 0xffffffff,
9071 (u_int)jtype, reverse, (u_int)jvalue);
9072 break;
9073
9074 case MH_OPC:
9075 newoff_opc+=3;
9076 case M_OPC:
9077 if (cstate->off_opc == OFFSET_NOT_SET)
9078 bpf_error(cstate, "'opc' supported only on SS7");
9079 /* opc coded on 14 bits so max value 16383 */
9080 if (jvalue > 16383)
9081 bpf_error(cstate, "opc value %u too big; max value = 16383",
9082 jvalue);
9083 /* the following instructions are made to convert jvalue
9084 * to the form used to write opc in an ss7 message*/
9085 val1 = jvalue & 0x00003c00;
9086 val1 = val1 >>10;
9087 val2 = jvalue & 0x000003fc;
9088 val2 = val2 <<6;
9089 val3 = jvalue & 0x00000003;
9090 val3 = val3 <<22;
9091 jvalue = val1 + val2 + val3;
9092 b0 = gen_ncmp(cstate, OR_PACKET, newoff_opc, BPF_W, 0x00c0ff0f,
9093 (u_int)jtype, reverse, (u_int)jvalue);
9094 break;
9095
9096 case MH_DPC:
9097 newoff_dpc += 3;
9098 /* FALLTHROUGH */
9099
9100 case M_DPC:
9101 if (cstate->off_dpc == OFFSET_NOT_SET)
9102 bpf_error(cstate, "'dpc' supported only on SS7");
9103 /* dpc coded on 14 bits so max value 16383 */
9104 if (jvalue > 16383)
9105 bpf_error(cstate, "dpc value %u too big; max value = 16383",
9106 jvalue);
9107 /* the following instructions are made to convert jvalue
9108 * to the forme used to write dpc in an ss7 message*/
9109 val1 = jvalue & 0x000000ff;
9110 val1 = val1 << 24;
9111 val2 = jvalue & 0x00003f00;
9112 val2 = val2 << 8;
9113 jvalue = val1 + val2;
9114 b0 = gen_ncmp(cstate, OR_PACKET, newoff_dpc, BPF_W, 0xff3f0000,
9115 (u_int)jtype, reverse, (u_int)jvalue);
9116 break;
9117
9118 case MH_SLS:
9119 newoff_sls+=3;
9120 case M_SLS:
9121 if (cstate->off_sls == OFFSET_NOT_SET)
9122 bpf_error(cstate, "'sls' supported only on SS7");
9123 /* sls coded on 4 bits so max value 15 */
9124 if (jvalue > 15)
9125 bpf_error(cstate, "sls value %u too big; max value = 15",
9126 jvalue);
9127 /* the following instruction is made to convert jvalue
9128 * to the forme used to write sls in an ss7 message*/
9129 jvalue = jvalue << 4;
9130 b0 = gen_ncmp(cstate, OR_PACKET, newoff_sls, BPF_B, 0xf0,
9131 (u_int)jtype,reverse, (u_int)jvalue);
9132 break;
9133
9134 default:
9135 abort();
9136 }
9137 return b0;
9138}
9139
9140static struct block *
9141gen_msg_abbrev(compiler_state_t *cstate, int type)
9142{
9143 struct block *b1;
9144
9145 /*
9146 * Q.2931 signalling protocol messages for handling virtual circuits
9147 * establishment and teardown
9148 */
9149 switch (type) {
9150
9151 case A_SETUP:
9152 b1 = gen_atmfield_code(cstate, A_MSGTYPE, SETUP, BPF_JEQ, 0);
9153 break;
9154
9155 case A_CALLPROCEED:
9156 b1 = gen_atmfield_code(cstate, A_MSGTYPE, CALL_PROCEED, BPF_JEQ, 0);
9157 break;
9158
9159 case A_CONNECT:
9160 b1 = gen_atmfield_code(cstate, A_MSGTYPE, CONNECT, BPF_JEQ, 0);
9161 break;
9162
9163 case A_CONNECTACK:
9164 b1 = gen_atmfield_code(cstate, A_MSGTYPE, CONNECT_ACK, BPF_JEQ, 0);
9165 break;
9166
9167 case A_RELEASE:
9168 b1 = gen_atmfield_code(cstate, A_MSGTYPE, RELEASE, BPF_JEQ, 0);
9169 break;
9170
9171 case A_RELEASE_DONE:
9172 b1 = gen_atmfield_code(cstate, A_MSGTYPE, RELEASE_DONE, BPF_JEQ, 0);
9173 break;
9174
9175 default:
9176 abort();
9177 }
9178 return b1;
9179}
9180
9181struct block *
9182gen_atmmulti_abbrev(compiler_state_t *cstate, int type)
9183{
9184 struct block *b0, *b1;
9185
9186 switch (type) {
9187
9188 case A_OAM:
9189 if (!cstate->is_atm)
9190 bpf_error(cstate, "'oam' supported only on raw ATM");
9191 b1 = gen_atmmulti_abbrev(cstate, A_OAMF4);
9192 break;
9193
9194 case A_OAMF4:
9195 if (!cstate->is_atm)
9196 bpf_error(cstate, "'oamf4' supported only on raw ATM");
9197 /* OAM F4 type */
9198 b0 = gen_atmfield_code(cstate, A_VCI, 3, BPF_JEQ, 0);
9199 b1 = gen_atmfield_code(cstate, A_VCI, 4, BPF_JEQ, 0);
9200 gen_or(b0, b1);
9201 b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
9202 gen_and(b0, b1);
9203 break;
9204
9205 case A_CONNECTMSG:
9206 /*
9207 * Get Q.2931 signalling messages for switched
9208 * virtual connection
9209 */
9210 if (!cstate->is_atm)
9211 bpf_error(cstate, "'connectmsg' supported only on raw ATM");
9212 b0 = gen_msg_abbrev(cstate, A_SETUP);
9213 b1 = gen_msg_abbrev(cstate, A_CALLPROCEED);
9214 gen_or(b0, b1);
9215 b0 = gen_msg_abbrev(cstate, A_CONNECT);
9216 gen_or(b0, b1);
9217 b0 = gen_msg_abbrev(cstate, A_CONNECTACK);
9218 gen_or(b0, b1);
9219 b0 = gen_msg_abbrev(cstate, A_RELEASE);
9220 gen_or(b0, b1);
9221 b0 = gen_msg_abbrev(cstate, A_RELEASE_DONE);
9222 gen_or(b0, b1);
9223 b0 = gen_atmtype_abbrev(cstate, A_SC);
9224 gen_and(b0, b1);
9225 break;
9226
9227 case A_METACONNECT:
9228 if (!cstate->is_atm)
9229 bpf_error(cstate, "'metaconnect' supported only on raw ATM");
9230 b0 = gen_msg_abbrev(cstate, A_SETUP);
9231 b1 = gen_msg_abbrev(cstate, A_CALLPROCEED);
9232 gen_or(b0, b1);
9233 b0 = gen_msg_abbrev(cstate, A_CONNECT);
9234 gen_or(b0, b1);
9235 b0 = gen_msg_abbrev(cstate, A_RELEASE);
9236 gen_or(b0, b1);
9237 b0 = gen_msg_abbrev(cstate, A_RELEASE_DONE);
9238 gen_or(b0, b1);
9239 b0 = gen_atmtype_abbrev(cstate, A_METAC);
9240 gen_and(b0, b1);
9241 break;
9242
9243 default:
9244 abort();
9245 }
9246 return b1;
9247}
9248