xref: /illumos-gate/usr/src/uts/common/inet/ipf/fil.c (revision af5f29dd)
1 /*
2  * Copyright (C) 1993-2003 by Darren Reed.
3  *
4  * See the IPFILTER.LICENCE file for details on licencing.
5  *
6  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
7  *
8  * Copyright (c) 2014, Joyent, Inc.  All rights reserved.
9  */
10 
11 #if defined(KERNEL) || defined(_KERNEL)
12 # undef KERNEL
13 # undef _KERNEL
14 # define        KERNEL	1
15 # define        _KERNEL	1
16 #endif
17 #include <sys/errno.h>
18 #include <sys/types.h>
19 #include <sys/param.h>
20 #include <sys/time.h>
21 #if defined(__NetBSD__)
22 # if (NetBSD >= 199905) && !defined(IPFILTER_LKM) && defined(_KERNEL)
23 #  include "opt_ipfilter_log.h"
24 # endif
25 #endif
26 #if defined(_KERNEL) && defined(__FreeBSD_version) && \
27     (__FreeBSD_version >= 220000)
28 # if (__FreeBSD_version >= 400000)
29 #  if !defined(IPFILTER_LKM)
30 #   include "opt_inet6.h"
31 #  endif
32 #  if (__FreeBSD_version == 400019)
33 #   define CSUM_DELAY_DATA
34 #  endif
35 # endif
36 # include <sys/filio.h>
37 #else
38 # include <sys/ioctl.h>
39 #endif
40 #if !defined(_AIX51)
41 # include <sys/fcntl.h>
42 #endif
43 #if defined(_KERNEL)
44 # include <sys/systm.h>
45 # include <sys/file.h>
46 #else
47 # include <stdio.h>
48 # include <string.h>
49 # include <stdlib.h>
50 # include <stddef.h>
51 # include <sys/file.h>
52 # define _KERNEL
53 # ifdef __OpenBSD__
54 struct file;
55 # endif
56 # include <sys/uio.h>
57 # undef _KERNEL
58 #endif
59 #if !defined(__SVR4) && !defined(__svr4__) && !defined(__hpux) && \
60     !defined(linux)
61 # include <sys/mbuf.h>
62 #else
63 # if !defined(linux)
64 #  include <sys/byteorder.h>
65 # endif
66 # if (SOLARIS2 < 5) && defined(sun)
67 #  include <sys/dditypes.h>
68 # endif
69 #endif
70 #ifdef __hpux
71 # define _NET_ROUTE_INCLUDED
72 #endif
73 #if !defined(linux)
74 # include <sys/protosw.h>
75 #endif
76 #include <sys/socket.h>
77 #include <net/if.h>
78 #ifdef sun
79 # include <net/af.h>
80 #endif
81 #if !defined(_KERNEL) && defined(__FreeBSD__)
82 # include "radix_ipf.h"
83 #endif
84 #include <net/route.h>
85 #include <netinet/in.h>
86 #include <netinet/in_systm.h>
87 #include <netinet/ip.h>
88 #if !defined(linux)
89 # include <netinet/ip_var.h>
90 #endif
91 #if defined(__sgi) && defined(IFF_DRVRLOCK) /* IRIX 6 */
92 # include <sys/hashing.h>
93 # include <netinet/in_var.h>
94 #endif
95 #include <netinet/tcp.h>
96 #if (!defined(__sgi) && !defined(AIX)) || defined(_KERNEL)
97 # include <netinet/udp.h>
98 # include <netinet/ip_icmp.h>
99 #endif
100 #ifdef __hpux
101 # undef _NET_ROUTE_INCLUDED
102 #endif
103 #include "netinet/ip_compat.h"
104 #ifdef	USE_INET6
105 # include <netinet/icmp6.h>
106 # if !defined(SOLARIS) && defined(_KERNEL) && !defined(__osf__) && \
107 	!defined(__hpux)
108 #  include <netinet6/in6_var.h>
109 # endif
110 #endif
111 #include <netinet/tcpip.h>
112 #include "netinet/ip_fil.h"
113 #include "netinet/ip_nat.h"
114 #include "netinet/ip_frag.h"
115 #include "netinet/ip_state.h"
116 #include "netinet/ip_proxy.h"
117 #include "netinet/ip_auth.h"
118 #include "netinet/ipf_stack.h"
119 #ifdef IPFILTER_SCAN
120 # include "netinet/ip_scan.h"
121 #endif
122 #ifdef IPFILTER_SYNC
123 # include "netinet/ip_sync.h"
124 #endif
125 #include "netinet/ip_pool.h"
126 #include "netinet/ip_htable.h"
127 #ifdef IPFILTER_COMPILED
128 # include "netinet/ip_rules.h"
129 #endif
130 #if defined(IPFILTER_BPF) && defined(_KERNEL)
131 # include <net/bpf.h>
132 #endif
133 #if defined(__FreeBSD_version) && (__FreeBSD_version >= 300000)
134 # include <sys/malloc.h>
135 # if defined(_KERNEL) && !defined(IPFILTER_LKM)
136 #  include "opt_ipfilter.h"
137 # endif
138 #endif
139 #include "netinet/ipl.h"
140 #if defined(_KERNEL)
141 #include <sys/sunddi.h>
142 #endif
143 /* END OF INCLUDES */
144 
145 #if !defined(lint)
146 static const char sccsid[] = "@(#)fil.c	1.36 6/5/96 (C) 1993-2000 Darren Reed";
147 static const char rcsid[] = "@(#)$Id: fil.c,v 2.243.2.64 2005/08/13 05:19:59 darrenr Exp $";
148 #endif
149 
150 #ifndef	_KERNEL
151 # include "ipf.h"
152 # include "ipt.h"
153 # include "bpf-ipf.h"
154 extern	int	opts;
155 
156 # define	FR_VERBOSE(verb_pr)			verbose verb_pr
157 # define	FR_DEBUG(verb_pr)			debug verb_pr
158 #else /* #ifndef _KERNEL */
159 # define	FR_VERBOSE(verb_pr)
160 # define	FR_DEBUG(verb_pr)
161 #endif /* _KERNEL */
162 
163 
164 char	ipfilter_version[] = IPL_VERSION;
165 int	fr_features = 0
166 #ifdef	IPFILTER_LKM
167 		| IPF_FEAT_LKM
168 #endif
169 #ifdef	IPFILTER_LOG
170 		| IPF_FEAT_LOG
171 #endif
172 #ifdef	IPFILTER_LOOKUP
173 		| IPF_FEAT_LOOKUP
174 #endif
175 #ifdef	IPFILTER_BPF
176 		| IPF_FEAT_BPF
177 #endif
178 #ifdef	IPFILTER_COMPILED
179 		| IPF_FEAT_COMPILED
180 #endif
181 #ifdef	IPFILTER_CKSUM
182 		| IPF_FEAT_CKSUM
183 #endif
184 #ifdef	IPFILTER_SYNC
185 		| IPF_FEAT_SYNC
186 #endif
187 #ifdef	IPFILTER_SCAN
188 		| IPF_FEAT_SCAN
189 #endif
190 #ifdef	USE_INET6
191 		| IPF_FEAT_IPV6
192 #endif
193 	;
194 
195 #define	IPF_BUMP(x)	(x)++
196 
197 static	INLINE int	fr_ipfcheck __P((fr_info_t *, frentry_t *, int));
198 static	INLINE int	fr_ipfcheck __P((fr_info_t *, frentry_t *, int));
199 static	int		fr_portcheck __P((frpcmp_t *, u_short *));
200 static	int		frflushlist __P((int, minor_t, int *, frentry_t **,
201 					 ipf_stack_t *));
202 static	ipfunc_t	fr_findfunc __P((ipfunc_t));
203 static	frentry_t	*fr_firewall __P((fr_info_t *, u_32_t *));
204 static	int		fr_funcinit __P((frentry_t *fr, ipf_stack_t *));
205 static	INLINE void	frpr_ah __P((fr_info_t *));
206 static	INLINE void	frpr_esp __P((fr_info_t *));
207 static	INLINE void	frpr_gre __P((fr_info_t *));
208 static	INLINE void	frpr_udp __P((fr_info_t *));
209 static	INLINE void	frpr_tcp __P((fr_info_t *));
210 static	INLINE void	frpr_icmp __P((fr_info_t *));
211 static	INLINE void	frpr_ipv4hdr __P((fr_info_t *));
212 static	INLINE int	frpr_pullup __P((fr_info_t *, int));
213 static	INLINE void	frpr_short __P((fr_info_t *, int));
214 static	INLINE void	frpr_tcpcommon __P((fr_info_t *));
215 static	INLINE void	frpr_udpcommon __P((fr_info_t *));
216 static	INLINE int	fr_updateipid __P((fr_info_t *));
217 #ifdef	IPFILTER_LOOKUP
218 static	int		fr_grpmapinit __P((frentry_t *fr, ipf_stack_t *));
219 static	INLINE void	*fr_resolvelookup __P((u_int, u_int, lookupfunc_t *,
220 					       ipf_stack_t *));
221 #endif
222 static	void		frsynclist __P((int, int, void *, char *, frentry_t *,
223     ipf_stack_t *));
224 static	void		*fr_ifsync __P((int, int, char *, char *,
225 					void *, void *, ipf_stack_t *));
226 static	ipftuneable_t	*fr_findtunebyname __P((const char *, ipf_stack_t *));
227 static	ipftuneable_t	*fr_findtunebycookie __P((void *, void **, ipf_stack_t *));
228 
229 /*
230  * bit values for identifying presence of individual IP options
231  * All of these tables should be ordered by increasing key value on the left
232  * hand side to allow for binary searching of the array and include a trailer
233  * with a 0 for the bitmask for linear searches to easily find the end with.
234  */
235 const	struct	optlist	ipopts[20] = {
236 	{ IPOPT_NOP,	0x000001 },
237 	{ IPOPT_RR,	0x000002 },
238 	{ IPOPT_ZSU,	0x000004 },
239 	{ IPOPT_MTUP,	0x000008 },
240 	{ IPOPT_MTUR,	0x000010 },
241 	{ IPOPT_ENCODE,	0x000020 },
242 	{ IPOPT_TS,	0x000040 },
243 	{ IPOPT_TR,	0x000080 },
244 	{ IPOPT_SECURITY, 0x000100 },
245 	{ IPOPT_LSRR,	0x000200 },
246 	{ IPOPT_E_SEC,	0x000400 },
247 	{ IPOPT_CIPSO,	0x000800 },
248 	{ IPOPT_SATID,	0x001000 },
249 	{ IPOPT_SSRR,	0x002000 },
250 	{ IPOPT_ADDEXT,	0x004000 },
251 	{ IPOPT_VISA,	0x008000 },
252 	{ IPOPT_IMITD,	0x010000 },
253 	{ IPOPT_EIP,	0x020000 },
254 	{ IPOPT_FINN,	0x040000 },
255 	{ 0,		0x000000 }
256 };
257 
258 #ifdef USE_INET6
259 struct optlist ip6exthdr[] = {
260 	{ IPPROTO_HOPOPTS,		0x000001 },
261 	{ IPPROTO_IPV6,			0x000002 },
262 	{ IPPROTO_ROUTING,		0x000004 },
263 	{ IPPROTO_FRAGMENT,		0x000008 },
264 	{ IPPROTO_ESP,			0x000010 },
265 	{ IPPROTO_AH,			0x000020 },
266 	{ IPPROTO_NONE,			0x000040 },
267 	{ IPPROTO_DSTOPTS,		0x000080 },
268 	{ 0,				0 }
269 };
270 #endif
271 
272 struct optlist tcpopts[] = {
273 	{ TCPOPT_NOP,			0x000001 },
274 	{ TCPOPT_MAXSEG,		0x000002 },
275 	{ TCPOPT_WINDOW,		0x000004 },
276 	{ TCPOPT_SACK_PERMITTED,	0x000008 },
277 	{ TCPOPT_SACK,			0x000010 },
278 	{ TCPOPT_TIMESTAMP,		0x000020 },
279 	{ 0,				0x000000 }
280 };
281 
282 /*
283  * bit values for identifying presence of individual IP security options
284  */
285 const	struct	optlist	secopt[8] = {
286 	{ IPSO_CLASS_RES4,	0x01 },
287 	{ IPSO_CLASS_TOPS,	0x02 },
288 	{ IPSO_CLASS_SECR,	0x04 },
289 	{ IPSO_CLASS_RES3,	0x08 },
290 	{ IPSO_CLASS_CONF,	0x10 },
291 	{ IPSO_CLASS_UNCL,	0x20 },
292 	{ IPSO_CLASS_RES2,	0x40 },
293 	{ IPSO_CLASS_RES1,	0x80 }
294 };
295 
296 
297 /*
298  * Table of functions available for use with call rules.
299  */
300 static ipfunc_resolve_t fr_availfuncs[] = {
301 #ifdef	IPFILTER_LOOKUP
302 	{ "fr_srcgrpmap", fr_srcgrpmap, fr_grpmapinit },
303 	{ "fr_dstgrpmap", fr_dstgrpmap, fr_grpmapinit },
304 #endif
305 	{ "", NULL }
306 };
307 
308 
309 /*
310  * Below we declare a list of constants used only by the ipf_extraflush()
311  * routine.  We are placing it here, instead of in ipf_extraflush() itself,
312  * because we want to make it visible to tools such as mdb, nm etc., so the
313  * values can easily be altered during debugging.
314  */
315 static	const	int	idletime_tab[] = {
316 	IPF_TTLVAL(30),		/* 30 seconds */
317 	IPF_TTLVAL(1800),	/* 30 minutes */
318 	IPF_TTLVAL(43200),	/* 12 hours */
319 	IPF_TTLVAL(345600),	/* 4 days */
320 };
321 
322 
323 /*
324  * The next section of code is a a collection of small routines that set
325  * fields in the fr_info_t structure passed based on properties of the
326  * current packet.  There are different routines for the same protocol
327  * for each of IPv4 and IPv6.  Adding a new protocol, for which there
328  * will "special" inspection for setup, is now more easily done by adding
329  * a new routine and expanding the frpr_ipinit*() function rather than by
330  * adding more code to a growing switch statement.
331  */
332 #ifdef USE_INET6
333 static	INLINE int	frpr_ah6 __P((fr_info_t *));
334 static	INLINE void	frpr_esp6 __P((fr_info_t *));
335 static	INLINE void	frpr_gre6 __P((fr_info_t *));
336 static	INLINE void	frpr_udp6 __P((fr_info_t *));
337 static	INLINE void	frpr_tcp6 __P((fr_info_t *));
338 static	INLINE void	frpr_icmp6 __P((fr_info_t *));
339 static	INLINE void	frpr_ipv6hdr __P((fr_info_t *));
340 static	INLINE void	frpr_short6 __P((fr_info_t *, int));
341 static	INLINE int	frpr_hopopts6 __P((fr_info_t *));
342 static	INLINE int	frpr_routing6 __P((fr_info_t *));
343 static	INLINE int	frpr_dstopts6 __P((fr_info_t *));
344 static	INLINE int	frpr_fragment6 __P((fr_info_t *));
345 static	INLINE int	frpr_ipv6exthdr __P((fr_info_t *, int, int));
346 
347 
348 /* ------------------------------------------------------------------------ */
349 /* Function:    frpr_short6                                                 */
350 /* Returns:     void                                                        */
351 /* Parameters:  fin(I) - pointer to packet information                      */
352 /*                                                                          */
353 /* IPv6 Only                                                                */
354 /* This is function enforces the 'is a packet too short to be legit' rule   */
355 /* for IPv6 and marks the packet with FI_SHORT if so.  See function comment */
356 /* for frpr_short() for more details.                                       */
357 /* ------------------------------------------------------------------------ */
frpr_short6(fin,xmin)358 static INLINE void frpr_short6(fin, xmin)
359 fr_info_t *fin;
360 int xmin;
361 {
362 
363 	if (fin->fin_dlen < xmin)
364 		fin->fin_flx |= FI_SHORT;
365 }
366 
367 
368 /* ------------------------------------------------------------------------ */
369 /* Function:    frpr_ipv6hdr                                                */
370 /* Returns:     Nil                                                         */
371 /* Parameters:  fin(I) - pointer to packet information                      */
372 /*                                                                          */
373 /* IPv6 Only                                                                */
374 /* Copy values from the IPv6 header into the fr_info_t struct and call the  */
375 /* per-protocol analyzer if it exists.                                      */
376 /* ------------------------------------------------------------------------ */
frpr_ipv6hdr(fin)377 static INLINE void frpr_ipv6hdr(fin)
378 fr_info_t *fin;
379 {
380 	ip6_t *ip6 = (ip6_t *)fin->fin_ip;
381 	int p, go = 1, i, hdrcount;
382 	fr_ip_t *fi = &fin->fin_fi;
383 
384 	fin->fin_off = 0;
385 
386 	fi->fi_tos = 0;
387 	fi->fi_optmsk = 0;
388 	fi->fi_secmsk = 0;
389 	fi->fi_auth = 0;
390 
391 	p = ip6->ip6_nxt;
392 	fi->fi_ttl = ip6->ip6_hlim;
393 	fi->fi_src.in6 = ip6->ip6_src;
394 	fi->fi_dst.in6 = ip6->ip6_dst;
395 	fin->fin_id = 0;
396 
397 	hdrcount = 0;
398 	while (go && !(fin->fin_flx & (FI_BAD|FI_SHORT))) {
399 		switch (p)
400 		{
401 		case IPPROTO_UDP :
402 			frpr_udp6(fin);
403 			go = 0;
404 			break;
405 
406 		case IPPROTO_TCP :
407 			frpr_tcp6(fin);
408 			go = 0;
409 			break;
410 
411 		case IPPROTO_ICMPV6 :
412 			frpr_icmp6(fin);
413 			go = 0;
414 			break;
415 
416 		case IPPROTO_GRE :
417 			frpr_gre6(fin);
418 			go = 0;
419 			break;
420 
421 		case IPPROTO_HOPOPTS :
422 			/*
423 			 * hop by hop ext header is only allowed
424 			 * right after IPv6 header.
425 			 */
426 			if (hdrcount != 0) {
427 				fin->fin_flx |= FI_BAD;
428 				p = IPPROTO_NONE;
429 			} else {
430 				p = frpr_hopopts6(fin);
431 			}
432 			break;
433 
434 		case IPPROTO_DSTOPTS :
435 			p = frpr_dstopts6(fin);
436 			break;
437 
438 		case IPPROTO_ROUTING :
439 			p = frpr_routing6(fin);
440 			break;
441 
442 		case IPPROTO_AH :
443 			p = frpr_ah6(fin);
444 			break;
445 
446 		case IPPROTO_ESP :
447 			frpr_esp6(fin);
448 			go = 0;
449 			break;
450 
451 		case IPPROTO_IPV6 :
452 			for (i = 0; ip6exthdr[i].ol_bit != 0; i++)
453 				if (ip6exthdr[i].ol_val == p) {
454 					fin->fin_flx |= ip6exthdr[i].ol_bit;
455 					break;
456 				}
457 			go = 0;
458 			break;
459 
460 		case IPPROTO_NONE :
461 			go = 0;
462 			break;
463 
464 		case IPPROTO_FRAGMENT :
465 			p = frpr_fragment6(fin);
466 			if (fin->fin_off != 0)  /* Not the first frag */
467 				go = 0;
468 			break;
469 
470 		default :
471 			go = 0;
472 			break;
473 		}
474 		hdrcount++;
475 
476 		/*
477 		 * It is important to note that at this point, for the
478 		 * extension headers (go != 0), the entire header may not have
479 		 * been pulled up when the code gets to this point.  This is
480 		 * only done for "go != 0" because the other header handlers
481 		 * will all pullup their complete header.  The other indicator
482 		 * of an incomplete packet is that this was just an extension
483 		 * header.
484 		 */
485 		if ((go != 0) && (p != IPPROTO_NONE) &&
486 		    (frpr_pullup(fin, 0) == -1)) {
487 			p = IPPROTO_NONE;
488 			go = 0;
489 		}
490 	}
491 	fi->fi_p = p;
492 }
493 
494 
495 /* ------------------------------------------------------------------------ */
496 /* Function:    frpr_ipv6exthdr                                             */
497 /* Returns:     int    - value of the next header or IPPROTO_NONE if error  */
498 /* Parameters:  fin(I)      - pointer to packet information                 */
499 /*              multiple(I) - flag indicating yes/no if multiple occurances */
500 /*                            of this extension header are allowed.         */
501 /*              proto(I)    - protocol number for this extension header     */
502 /*                                                                          */
503 /* IPv6 Only                                                                */
504 /* This function expects to find an IPv6 extension header at fin_dp.        */
505 /* There must be at least 8 bytes of data at fin_dp for there to be a valid */
506 /* extension header present. If a good one is found, fin_dp is advanced to  */
507 /* point at the first piece of data after the extension header, fin_exthdr  */
508 /* points to the start of the extension header and the "protocol" of the    */
509 /* *NEXT* header is returned.                                               */
510 /* ------------------------------------------------------------------------ */
frpr_ipv6exthdr(fin,multiple,proto)511 static INLINE int frpr_ipv6exthdr(fin, multiple, proto)
512 fr_info_t *fin;
513 int multiple, proto;
514 {
515 	struct ip6_ext *hdr;
516 	u_short shift;
517 	int i;
518 
519 	fin->fin_flx |= FI_V6EXTHDR;
520 
521 				/* 8 is default length of extension hdr */
522 	if ((fin->fin_dlen - 8) < 0) {
523 		fin->fin_flx |= FI_SHORT;
524 		return IPPROTO_NONE;
525 	}
526 
527 	if (frpr_pullup(fin, 8) == -1)
528 		return IPPROTO_NONE;
529 
530 	hdr = fin->fin_dp;
531 	shift = 8 + (hdr->ip6e_len << 3);
532 	if (shift > fin->fin_dlen) {	/* Nasty extension header length? */
533 		fin->fin_flx |= FI_BAD;
534 		return IPPROTO_NONE;
535 	}
536 
537 	for (i = 0; ip6exthdr[i].ol_bit != 0; i++)
538 		if (ip6exthdr[i].ol_val == proto) {
539 			/*
540 			 * Most IPv6 extension headers are only allowed once.
541 			 */
542 			if ((multiple == 0) &&
543 			    ((fin->fin_optmsk & ip6exthdr[i].ol_bit) != 0))
544 				fin->fin_flx |= FI_BAD;
545 			else
546 				fin->fin_optmsk |= ip6exthdr[i].ol_bit;
547 			break;
548 		}
549 
550 	fin->fin_dp = (char *)fin->fin_dp + shift;
551 	fin->fin_dlen -= shift;
552 
553 	return hdr->ip6e_nxt;
554 }
555 
556 
557 /* ------------------------------------------------------------------------ */
558 /* Function:    frpr_hopopts6                                               */
559 /* Returns:     int    - value of the next header or IPPROTO_NONE if error  */
560 /* Parameters:  fin(I) - pointer to packet information                      */
561 /*                                                                          */
562 /* IPv6 Only                                                                */
563 /* This is function checks pending hop by hop options extension header      */
564 /* ------------------------------------------------------------------------ */
frpr_hopopts6(fin)565 static INLINE int frpr_hopopts6(fin)
566 fr_info_t *fin;
567 {
568 	return frpr_ipv6exthdr(fin, 0, IPPROTO_HOPOPTS);
569 }
570 
571 
572 /* ------------------------------------------------------------------------ */
573 /* Function:    frpr_routing6                                               */
574 /* Returns:     int    - value of the next header or IPPROTO_NONE if error  */
575 /* Parameters:  fin(I) - pointer to packet information                      */
576 /*                                                                          */
577 /* IPv6 Only                                                                */
578 /* This is function checks pending routing extension header                 */
579 /* ------------------------------------------------------------------------ */
frpr_routing6(fin)580 static INLINE int frpr_routing6(fin)
581 fr_info_t *fin;
582 {
583 	struct ip6_ext *hdr;
584 	int shift;
585 
586 	hdr = fin->fin_dp;
587 	if (frpr_ipv6exthdr(fin, 0, IPPROTO_ROUTING) == IPPROTO_NONE)
588 		return IPPROTO_NONE;
589 
590 	shift = 8 + (hdr->ip6e_len << 3);
591 	/*
592 	 * Nasty extension header length?
593 	 */
594 	if ((hdr->ip6e_len << 3) & 15) {
595 		fin->fin_flx |= FI_BAD;
596 		/*
597 		 * Compensate for the changes made in frpr_ipv6exthdr()
598 		 */
599 		fin->fin_dlen += shift;
600 		fin->fin_dp = (char *)fin->fin_dp - shift;
601 		return IPPROTO_NONE;
602 	}
603 
604 	return hdr->ip6e_nxt;
605 }
606 
607 
608 /* ------------------------------------------------------------------------ */
609 /* Function:    frpr_fragment6                                              */
610 /* Returns:     int    - value of the next header or IPPROTO_NONE if error  */
611 /* Parameters:  fin(I) - pointer to packet information                      */
612 /*                                                                          */
613 /* IPv6 Only                                                                */
614 /* Examine the IPv6 fragment header and extract fragment offset information.*/
615 /*                                                                          */
616 /* We don't know where the transport layer header (or whatever is next is), */
617 /* as it could be behind destination options (amongst others).  Because     */
618 /* there is no fragment cache, there is no knowledge about whether or not an*/
619 /* upper layer header has been seen (or where it ends) and thus we are not  */
620 /* able to continue processing beyond this header with any confidence.      */
621 /* ------------------------------------------------------------------------ */
frpr_fragment6(fin)622 static INLINE int frpr_fragment6(fin)
623 fr_info_t *fin;
624 {
625 	struct ip6_frag *frag;
626 
627 	fin->fin_flx |= FI_FRAG;
628 
629 	/*
630 	 * A fragmented IPv6 packet implies that there must be something
631 	 * else after the fragment.
632 	 */
633 	if (frpr_ipv6exthdr(fin, 0, IPPROTO_FRAGMENT) == IPPROTO_NONE)
634 		return IPPROTO_NONE;
635 
636 	frag = (struct ip6_frag *)((char *)fin->fin_dp - sizeof(*frag));
637 
638 	/*
639 	 * If this fragment isn't the last then the packet length must
640 	 * be a multiple of 8.
641 	 */
642 	if ((frag->ip6f_offlg & IP6F_MORE_FRAG) != 0) {
643 		fin->fin_flx |= FI_MOREFRAG;
644 
645 		if ((fin->fin_plen & 0x7) != 0)
646 			fin->fin_flx |= FI_BAD;
647 	}
648 
649 	fin->fin_id = frag->ip6f_ident;
650 	fin->fin_off = ntohs(frag->ip6f_offlg & IP6F_OFF_MASK);
651 	if (fin->fin_off != 0)
652 		fin->fin_flx |= FI_FRAGBODY;
653 
654 	return frag->ip6f_nxt;
655 }
656 
657 
658 /* ------------------------------------------------------------------------ */
659 /* Function:    frpr_dstopts6                                               */
660 /* Returns:     int    - value of the next header or IPPROTO_NONE if error  */
661 /* Parameters:  fin(I) - pointer to packet information                      */
662 /*              nextheader(I) - stores next header value                    */
663 /*                                                                          */
664 /* IPv6 Only                                                                */
665 /* This is function checks pending destination options extension header     */
666 /* ------------------------------------------------------------------------ */
frpr_dstopts6(fin)667 static INLINE int frpr_dstopts6(fin)
668 fr_info_t *fin;
669 {
670 	return frpr_ipv6exthdr(fin, 1, IPPROTO_DSTOPTS);
671 }
672 
673 
674 /* ------------------------------------------------------------------------ */
675 /* Function:    frpr_icmp6                                                  */
676 /* Returns:     void                                                        */
677 /* Parameters:  fin(I) - pointer to packet information                      */
678 /*                                                                          */
679 /* IPv6 Only                                                                */
680 /* This routine is mainly concerned with determining the minimum valid size */
681 /* for an ICMPv6 packet.                                                    */
682 /* ------------------------------------------------------------------------ */
frpr_icmp6(fin)683 static INLINE void frpr_icmp6(fin)
684 fr_info_t *fin;
685 {
686 	int minicmpsz = sizeof(struct icmp6_hdr);
687 	struct icmp6_hdr *icmp6;
688 
689 	if (frpr_pullup(fin, ICMP6ERR_MINPKTLEN - sizeof(ip6_t)) == -1)
690 		return;
691 
692 	if (fin->fin_dlen > 1) {
693 		icmp6 = fin->fin_dp;
694 
695 		fin->fin_data[0] = *(u_short *)icmp6;
696 
697 		if ((icmp6->icmp6_type & ICMP6_INFOMSG_MASK) != 0)
698 			fin->fin_flx |= FI_ICMPQUERY;
699 
700 		switch (icmp6->icmp6_type)
701 		{
702 		case ICMP6_ECHO_REPLY :
703 		case ICMP6_ECHO_REQUEST :
704 			if (fin->fin_dlen >= 6)
705 				fin->fin_data[1] = icmp6->icmp6_id;
706 			minicmpsz = ICMP6ERR_MINPKTLEN - sizeof(ip6_t);
707 			break;
708 		case ICMP6_DST_UNREACH :
709 		case ICMP6_PACKET_TOO_BIG :
710 		case ICMP6_TIME_EXCEEDED :
711 		case ICMP6_PARAM_PROB :
712 			if ((fin->fin_m != NULL) &&
713 			    (M_LEN(fin->fin_m) < fin->fin_plen)) {
714 				if (fr_coalesce(fin) != 1)
715 					return;
716 			}
717 			fin->fin_flx |= FI_ICMPERR;
718 			minicmpsz = ICMP6ERR_IPICMPHLEN - sizeof(ip6_t);
719 			break;
720 		default :
721 			break;
722 		}
723 	}
724 
725 	frpr_short6(fin, minicmpsz);
726 }
727 
728 
729 /* ------------------------------------------------------------------------ */
730 /* Function:    frpr_udp6                                                   */
731 /* Returns:     void                                                        */
732 /* Parameters:  fin(I) - pointer to packet information                      */
733 /*                                                                          */
734 /* IPv6 Only                                                                */
735 /* Analyse the packet for IPv6/UDP properties.                              */
736 /* Is not expected to be called for fragmented packets.                     */
737 /* ------------------------------------------------------------------------ */
frpr_udp6(fin)738 static INLINE void frpr_udp6(fin)
739 fr_info_t *fin;
740 {
741 
742 	fr_checkv6sum(fin);
743 
744 	frpr_short6(fin, sizeof(struct udphdr));
745 	if (frpr_pullup(fin, sizeof(struct udphdr)) == -1)
746 		return;
747 
748 	frpr_udpcommon(fin);
749 }
750 
751 
752 /* ------------------------------------------------------------------------ */
753 /* Function:    frpr_tcp6                                                   */
754 /* Returns:     void                                                        */
755 /* Parameters:  fin(I) - pointer to packet information                      */
756 /*                                                                          */
757 /* IPv6 Only                                                                */
758 /* Analyse the packet for IPv6/TCP properties.                              */
759 /* Is not expected to be called for fragmented packets.                     */
760 /* ------------------------------------------------------------------------ */
frpr_tcp6(fin)761 static INLINE void frpr_tcp6(fin)
762 fr_info_t *fin;
763 {
764 
765 	fr_checkv6sum(fin);
766 
767 	frpr_short6(fin, sizeof(struct tcphdr));
768 	if (frpr_pullup(fin, sizeof(struct tcphdr)) == -1)
769 		return;
770 
771 	frpr_tcpcommon(fin);
772 }
773 
774 
775 /* ------------------------------------------------------------------------ */
776 /* Function:    frpr_esp6                                                   */
777 /* Returns:     void                                                        */
778 /* Parameters:  fin(I) - pointer to packet information                      */
779 /*                                                                          */
780 /* IPv6 Only                                                                */
781 /* Analyse the packet for ESP properties.                                   */
782 /* The minimum length is taken to be the SPI (32bits) plus a tail (32bits)  */
783 /* even though the newer ESP packets must also have a sequence number that  */
784 /* is 32bits as well, it is not possible(?) to determine the version from a */
785 /* simple packet header.                                                    */
786 /* ------------------------------------------------------------------------ */
frpr_esp6(fin)787 static INLINE void frpr_esp6(fin)
788 fr_info_t *fin;
789 {
790 	int i;
791 	frpr_short6(fin, sizeof(grehdr_t));
792 
793 	(void) frpr_pullup(fin, 8);
794 
795 	for (i = 0; ip6exthdr[i].ol_bit != 0; i++)
796 		if (ip6exthdr[i].ol_val == IPPROTO_ESP) {
797 			fin->fin_optmsk |= ip6exthdr[i].ol_bit;
798 			break;
799 		}
800 }
801 
802 
803 /* ------------------------------------------------------------------------ */
804 /* Function:    frpr_ah6                                                    */
805 /* Returns:     void                                                        */
806 /* Parameters:  fin(I) - pointer to packet information                      */
807 /*                                                                          */
808 /* IPv6 Only                                                                */
809 /* Analyse the packet for AH properties.                                    */
810 /* The minimum length is taken to be the combination of all fields in the   */
811 /* header being present and no authentication data (null algorithm used.)   */
812 /* ------------------------------------------------------------------------ */
frpr_ah6(fin)813 static INLINE int frpr_ah6(fin)
814 fr_info_t *fin;
815 {
816 	authhdr_t *ah;
817 	int i, shift;
818 
819 	frpr_short6(fin, 12);
820 
821 	if (frpr_pullup(fin, sizeof(*ah)) == -1)
822 		return IPPROTO_NONE;
823 
824 	for (i = 0; ip6exthdr[i].ol_bit != 0; i++)
825 		if (ip6exthdr[i].ol_val == IPPROTO_AH) {
826 			fin->fin_optmsk |= ip6exthdr[i].ol_bit;
827 			break;
828 		}
829 
830 	ah = (authhdr_t *)fin->fin_dp;
831 
832 	shift = (ah->ah_plen + 2) * 4;
833 	fin->fin_dlen -= shift;
834 	fin->fin_dp = (char*)fin->fin_dp + shift;
835 
836 	return ah->ah_next;
837 }
838 
839 
840 /* ------------------------------------------------------------------------ */
841 /* Function:    frpr_gre6                                                   */
842 /* Returns:     void                                                        */
843 /* Parameters:  fin(I) - pointer to packet information                      */
844 /*                                                                          */
845 /* Analyse the packet for GRE properties.                                   */
846 /* ------------------------------------------------------------------------ */
frpr_gre6(fin)847 static INLINE void frpr_gre6(fin)
848 fr_info_t *fin;
849 {
850 	grehdr_t *gre;
851 
852 	frpr_short6(fin, sizeof(grehdr_t));
853 
854 	if (frpr_pullup(fin, sizeof(grehdr_t)) == -1)
855 		return;
856 
857 	gre = fin->fin_dp;
858 	if (GRE_REV(gre->gr_flags) == 1)
859 		fin->fin_data[0] = gre->gr_call;
860 }
861 #endif	/* USE_INET6 */
862 
863 
864 /* ------------------------------------------------------------------------ */
865 /* Function:    frpr_pullup                                                 */
866 /* Returns:     int     - 0 == pullup succeeded, -1 == failure              */
867 /* Parameters:  fin(I)  - pointer to packet information                     */
868 /*              plen(I) - length (excluding L3 header) to pullup            */
869 /*                                                                          */
870 /* Short inline function to cut down on code duplication to perform a call  */
871 /* to fr_pullup to ensure there is the required amount of data,             */
872 /* consecutively in the packet buffer.                                      */
873 /* ------------------------------------------------------------------------ */
frpr_pullup(fin,plen)874 static INLINE int frpr_pullup(fin, plen)
875 fr_info_t *fin;
876 int plen;
877 {
878 #if defined(_KERNEL)
879 	if (fin->fin_m != NULL) {
880 		int ipoff;
881 
882 		ipoff = (char *)fin->fin_ip - MTOD(fin->fin_m, char *);
883 
884 		if (fin->fin_dp != NULL)
885 			plen += (char *)fin->fin_dp -
886 				((char *)fin->fin_ip + fin->fin_hlen);
887 		plen += fin->fin_hlen;
888 		/*
889 		 * We don't do 'plen += ipoff;' here. The fr_pullup() will
890 		 * do it for us.
891 		 */
892 		if (M_LEN(fin->fin_m) < plen + ipoff) {
893 			if (fr_pullup(fin->fin_m, fin, plen) == NULL)
894 				return -1;
895 		}
896 	}
897 #endif
898 	return 0;
899 }
900 
901 
902 /* ------------------------------------------------------------------------ */
903 /* Function:    frpr_short                                                  */
904 /* Returns:     void                                                        */
905 /* Parameters:  fin(I)  - pointer to packet information                     */
906 /*              xmin(I) - minimum header size                               */
907 /*                                                                          */
908 /* Check if a packet is "short" as defined by xmin.  The rule we are        */
909 /* applying here is that the packet must not be fragmented within the layer */
910 /* 4 header.  That is, it must not be a fragment that has its offset set to */
911 /* start within the layer 4 header (hdrmin) or if it is at offset 0, the    */
912 /* entire layer 4 header must be present (min).                             */
913 /* ------------------------------------------------------------------------ */
frpr_short(fin,xmin)914 static INLINE void frpr_short(fin, xmin)
915 fr_info_t *fin;
916 int xmin;
917 {
918 
919 	if (fin->fin_off == 0) {
920 		if (fin->fin_dlen < xmin)
921 			fin->fin_flx |= FI_SHORT;
922 	} else if (fin->fin_off < xmin) {
923 		fin->fin_flx |= FI_SHORT;
924 	}
925 }
926 
927 
928 /* ------------------------------------------------------------------------ */
929 /* Function:    frpr_icmp                                                   */
930 /* Returns:     void                                                        */
931 /* Parameters:  fin(I) - pointer to packet information                      */
932 /*                                                                          */
933 /* IPv4 Only                                                                */
934 /* Do a sanity check on the packet for ICMP (v4).  In nearly all cases,     */
935 /* except extrememly bad packets, both type and code will be present.       */
936 /* The expected minimum size of an ICMP packet is very much dependent on    */
937 /* the type of it.                                                          */
938 /*                                                                          */
939 /* XXX - other ICMP sanity checks?                                          */
940 /* ------------------------------------------------------------------------ */
frpr_icmp(fin)941 static INLINE void frpr_icmp(fin)
942 fr_info_t *fin;
943 {
944 	int minicmpsz = sizeof(struct icmp);
945 	icmphdr_t *icmp;
946 	ip_t *oip;
947 	ipf_stack_t *ifs = fin->fin_ifs;
948 
949 	if (fin->fin_off != 0) {
950 		frpr_short(fin, ICMPERR_ICMPHLEN);
951 		return;
952 	}
953 
954 	if (frpr_pullup(fin, ICMPERR_ICMPHLEN) == -1)
955 		return;
956 
957 	fr_checkv4sum(fin);
958 
959 	/*
960 	 * This is a right place to set icmp pointer, since the memory
961 	 * referenced by fin_dp could get reallocated. The code down below can
962 	 * rely on fact icmp variable always points to ICMP header.
963 	 */
964 	icmp = fin->fin_dp;
965 	fin->fin_data[0] = *(u_short *)icmp;
966 	fin->fin_data[1] = icmp->icmp_id;
967 
968 	switch (icmp->icmp_type)
969 	{
970 	case ICMP_ECHOREPLY :
971 	case ICMP_ECHO :
972 	/* Router discovery messaes - RFC 1256 */
973 	case ICMP_ROUTERADVERT :
974 	case ICMP_ROUTERSOLICIT :
975 		minicmpsz = ICMP_MINLEN;
976 		break;
977 	/*
978 	 * type(1) + code(1) + cksum(2) + id(2) seq(2) +
979 	 * 3 * timestamp(3 * 4)
980 	 */
981 	case ICMP_TSTAMP :
982 	case ICMP_TSTAMPREPLY :
983 		minicmpsz = 20;
984 		break;
985 	/*
986 	 * type(1) + code(1) + cksum(2) + id(2) seq(2) +
987 	 * mask(4)
988 	 */
989 	case ICMP_MASKREQ :
990 	case ICMP_MASKREPLY :
991 			minicmpsz = 12;
992 			break;
993 	/*
994 	 * type(1) + code(1) + cksum(2) + id(2) seq(2) + ip(20+)
995 	 */
996 	case ICMP_UNREACH :
997 		if (icmp->icmp_code == ICMP_UNREACH_NEEDFRAG) {
998 			if (icmp->icmp_nextmtu < ifs->ifs_fr_icmpminfragmtu)
999 				fin->fin_flx |= FI_BAD;
1000 		}
1001 		/* FALLTHRU */
1002 	case ICMP_SOURCEQUENCH :
1003 	case ICMP_REDIRECT :
1004 	case ICMP_TIMXCEED :
1005 	case ICMP_PARAMPROB :
1006 		fin->fin_flx |= FI_ICMPERR;
1007 		if (fr_coalesce(fin) != 1)
1008 			return;
1009 		/*
1010 		 * ICMP error packets should not be generated for IP
1011 		 * packets that are a fragment that isn't the first
1012 		 * fragment.
1013 		 */
1014 		oip = (ip_t *)((char *)fin->fin_dp + ICMPERR_ICMPHLEN);
1015 		if ((ntohs(oip->ip_off) & IP_OFFMASK) != 0)
1016 			fin->fin_flx |= FI_BAD;
1017 		break;
1018 	default :
1019 		break;
1020 	}
1021 
1022 	frpr_short(fin, minicmpsz);
1023 }
1024 
1025 
1026 /* ------------------------------------------------------------------------ */
1027 /* Function:    frpr_tcpcommon                                              */
1028 /* Returns:     void                                                        */
1029 /* Parameters:  fin(I) - pointer to packet information                      */
1030 /*                                                                          */
1031 /* TCP header sanity checking.  Look for bad combinations of TCP flags,     */
1032 /* and make some checks with how they interact with other fields.           */
1033 /* If compiled with IPFILTER_CKSUM, check to see if the TCP checksum is     */
1034 /* valid and mark the packet as bad if not.                                 */
1035 /* ------------------------------------------------------------------------ */
frpr_tcpcommon(fin)1036 static INLINE void frpr_tcpcommon(fin)
1037 fr_info_t *fin;
1038 {
1039 	int flags, tlen;
1040 	tcphdr_t *tcp;
1041 
1042 	fin->fin_flx |= FI_TCPUDP;
1043 	if (fin->fin_off != 0)
1044 		return;
1045 
1046 	if (frpr_pullup(fin, sizeof(*tcp)) == -1)
1047 		return;
1048 	tcp = fin->fin_dp;
1049 
1050 	if (fin->fin_dlen > 3) {
1051 		fin->fin_sport = ntohs(tcp->th_sport);
1052 		fin->fin_dport = ntohs(tcp->th_dport);
1053 	}
1054 
1055 	if ((fin->fin_flx & FI_SHORT) != 0)
1056 		return;
1057 
1058 	/*
1059 	 * Use of the TCP data offset *must* result in a value that is at
1060 	 * least the same size as the TCP header.
1061 	 */
1062 	tlen = TCP_OFF(tcp) << 2;
1063 	if (tlen < sizeof(tcphdr_t)) {
1064 		fin->fin_flx |= FI_BAD;
1065 		return;
1066 	}
1067 
1068 	flags = tcp->th_flags;
1069 	fin->fin_tcpf = tcp->th_flags;
1070 
1071 	/*
1072 	 * If the urgent flag is set, then the urgent pointer must
1073 	 * also be set and vice versa.  Good TCP packets do not have
1074 	 * just one of these set.
1075 	 */
1076 	if ((flags & TH_URG) != 0 && (tcp->th_urp == 0)) {
1077 		fin->fin_flx |= FI_BAD;
1078 	} else if ((flags & TH_URG) == 0 && (tcp->th_urp != 0)) {
1079 		/* Ignore this case, it shows up in "real" traffic with */
1080 		/* bogus values in the urgent pointer field. */
1081 		flags = flags; /* LINT */
1082 	} else if (((flags & (TH_SYN|TH_FIN)) != 0) &&
1083 		   ((flags & (TH_RST|TH_ACK)) == TH_RST)) {
1084 		/* TH_FIN|TH_RST|TH_ACK seems to appear "naturally" */
1085 		fin->fin_flx |= FI_BAD;
1086 	} else if (!(flags & TH_ACK)) {
1087 		/*
1088 		 * If the ack bit isn't set, then either the SYN or
1089 		 * RST bit must be set.  If the SYN bit is set, then
1090 		 * we expect the ACK field to be 0.  If the ACK is
1091 		 * not set and if URG, PSH or FIN are set, consdier
1092 		 * that to indicate a bad TCP packet.
1093 		 */
1094 		if ((flags == TH_SYN) && (tcp->th_ack != 0)) {
1095 			/*
1096 			 * Cisco PIX sets the ACK field to a random value.
1097 			 * In light of this, do not set FI_BAD until a patch
1098 			 * is available from Cisco to ensure that
1099 			 * interoperability between existing systems is
1100 			 * achieved.
1101 			 */
1102 			/*fin->fin_flx |= FI_BAD*/;
1103 			flags = flags; /* LINT */
1104 		} else if (!(flags & (TH_RST|TH_SYN))) {
1105 			fin->fin_flx |= FI_BAD;
1106 		} else if ((flags & (TH_URG|TH_PUSH|TH_FIN)) != 0) {
1107 			fin->fin_flx |= FI_BAD;
1108 		}
1109 	}
1110 
1111 	/*
1112 	 * At this point, it's not exactly clear what is to be gained by
1113 	 * marking up which TCP options are and are not present.  The one we
1114 	 * are most interested in is the TCP window scale.  This is only in
1115 	 * a SYN packet [RFC1323] so we don't need this here...?
1116 	 * Now if we were to analyse the header for passive fingerprinting,
1117 	 * then that might add some weight to adding this...
1118 	 */
1119 	if (tlen == sizeof(tcphdr_t))
1120 		return;
1121 
1122 	if (frpr_pullup(fin, tlen) == -1)
1123 		return;
1124 
1125 #if 0
1126 	ip = fin->fin_ip;
1127 	s = (u_char *)(tcp + 1);
1128 	off = IP_HL(ip) << 2;
1129 # ifdef _KERNEL
1130 	if (fin->fin_mp != NULL) {
1131 		mb_t *m = *fin->fin_mp;
1132 
1133 		if (off + tlen > M_LEN(m))
1134 			return;
1135 	}
1136 # endif
1137 	for (tlen -= (int)sizeof(*tcp); tlen > 0; ) {
1138 		opt = *s;
1139 		if (opt == '\0')
1140 			break;
1141 		else if (opt == TCPOPT_NOP)
1142 			ol = 1;
1143 		else {
1144 			if (tlen < 2)
1145 				break;
1146 			ol = (int)*(s + 1);
1147 			if (ol < 2 || ol > tlen)
1148 				break;
1149 		}
1150 
1151 		for (i = 9, mv = 4; mv >= 0; ) {
1152 			op = ipopts + i;
1153 			if (opt == (u_char)op->ol_val) {
1154 				optmsk |= op->ol_bit;
1155 				break;
1156 			}
1157 		}
1158 		tlen -= ol;
1159 		s += ol;
1160 	}
1161 #endif /* 0 */
1162 }
1163 
1164 
1165 
1166 /* ------------------------------------------------------------------------ */
1167 /* Function:    frpr_udpcommon                                              */
1168 /* Returns:     void                                                        */
1169 /* Parameters:  fin(I) - pointer to packet information                      */
1170 /*                                                                          */
1171 /* Extract the UDP source and destination ports, if present.  If compiled   */
1172 /* with IPFILTER_CKSUM, check to see if the UDP checksum is valid.          */
1173 /* ------------------------------------------------------------------------ */
frpr_udpcommon(fin)1174 static INLINE void frpr_udpcommon(fin)
1175 fr_info_t *fin;
1176 {
1177 	udphdr_t *udp;
1178 
1179 	fin->fin_flx |= FI_TCPUDP;
1180 
1181 	if (!fin->fin_off && (fin->fin_dlen > 3)) {
1182 		if (frpr_pullup(fin, sizeof(*udp)) == -1) {
1183 			fin->fin_flx |= FI_SHORT;
1184 			return;
1185 		}
1186 
1187 		udp = fin->fin_dp;
1188 
1189 		fin->fin_sport = ntohs(udp->uh_sport);
1190 		fin->fin_dport = ntohs(udp->uh_dport);
1191 	}
1192 }
1193 
1194 
1195 /* ------------------------------------------------------------------------ */
1196 /* Function:    frpr_tcp                                                    */
1197 /* Returns:     void                                                        */
1198 /* Parameters:  fin(I) - pointer to packet information                      */
1199 /*                                                                          */
1200 /* IPv4 Only                                                                */
1201 /* Analyse the packet for IPv4/TCP properties.                              */
1202 /* ------------------------------------------------------------------------ */
frpr_tcp(fin)1203 static INLINE void frpr_tcp(fin)
1204 fr_info_t *fin;
1205 {
1206 
1207 	fr_checkv4sum(fin);
1208 
1209 	frpr_short(fin, sizeof(tcphdr_t));
1210 
1211 	frpr_tcpcommon(fin);
1212 }
1213 
1214 
1215 /* ------------------------------------------------------------------------ */
1216 /* Function:    frpr_udp                                                    */
1217 /* Returns:     void                                                        */
1218 /* Parameters:  fin(I) - pointer to packet information                      */
1219 /*                                                                          */
1220 /* IPv4 Only                                                                */
1221 /* Analyse the packet for IPv4/UDP properties.                              */
1222 /* ------------------------------------------------------------------------ */
frpr_udp(fin)1223 static INLINE void frpr_udp(fin)
1224 fr_info_t *fin;
1225 {
1226 
1227 	fr_checkv4sum(fin);
1228 
1229 	frpr_short(fin, sizeof(udphdr_t));
1230 
1231 	frpr_udpcommon(fin);
1232 }
1233 
1234 
1235 /* ------------------------------------------------------------------------ */
1236 /* Function:    frpr_esp                                                    */
1237 /* Returns:     void                                                        */
1238 /* Parameters:  fin(I) - pointer to packet information                      */
1239 /*                                                                          */
1240 /* Analyse the packet for ESP properties.                                   */
1241 /* The minimum length is taken to be the SPI (32bits) plus a tail (32bits)  */
1242 /* even though the newer ESP packets must also have a sequence number that  */
1243 /* is 32bits as well, it is not possible(?) to determine the version from a */
1244 /* simple packet header.                                                    */
1245 /* ------------------------------------------------------------------------ */
frpr_esp(fin)1246 static INLINE void frpr_esp(fin)
1247 fr_info_t *fin;
1248 {
1249 	if ((fin->fin_off == 0) && (frpr_pullup(fin, 8) == -1))
1250 		return;
1251 
1252 	frpr_short(fin, 8);
1253 }
1254 
1255 
1256 /* ------------------------------------------------------------------------ */
1257 /* Function:    frpr_ah                                                     */
1258 /* Returns:     void                                                        */
1259 /* Parameters:  fin(I) - pointer to packet information                      */
1260 /*                                                                          */
1261 /* Analyse the packet for AH properties.                                    */
1262 /* The minimum length is taken to be the combination of all fields in the   */
1263 /* header being present and no authentication data (null algorithm used.)   */
1264 /* ------------------------------------------------------------------------ */
frpr_ah(fin)1265 static INLINE void frpr_ah(fin)
1266 fr_info_t *fin;
1267 {
1268 	authhdr_t *ah;
1269 	int len;
1270 
1271 	if ((fin->fin_off == 0) && (frpr_pullup(fin, sizeof(*ah)) == -1))
1272 		return;
1273 
1274 	ah = (authhdr_t *)fin->fin_dp;
1275 
1276 	len = (ah->ah_plen + 2) << 2;
1277 	frpr_short(fin, len);
1278 }
1279 
1280 
1281 /* ------------------------------------------------------------------------ */
1282 /* Function:    frpr_gre                                                    */
1283 /* Returns:     void                                                        */
1284 /* Parameters:  fin(I) - pointer to packet information                      */
1285 /*                                                                          */
1286 /* Analyse the packet for GRE properties.                                   */
1287 /* ------------------------------------------------------------------------ */
frpr_gre(fin)1288 static INLINE void frpr_gre(fin)
1289 fr_info_t *fin;
1290 {
1291 	grehdr_t *gre;
1292 
1293 	if ((fin->fin_off == 0) && (frpr_pullup(fin, sizeof(grehdr_t)) == -1))
1294 		return;
1295 
1296 	frpr_short(fin, sizeof(grehdr_t));
1297 
1298 	if (fin->fin_off == 0) {
1299 		gre = fin->fin_dp;
1300 		if (GRE_REV(gre->gr_flags) == 1)
1301 			fin->fin_data[0] = gre->gr_call;
1302 	}
1303 }
1304 
1305 
1306 /* ------------------------------------------------------------------------ */
1307 /* Function:    frpr_ipv4hdr                                                */
1308 /* Returns:     void                                                        */
1309 /* Parameters:  fin(I) - pointer to packet information                      */
1310 /*                                                                          */
1311 /* IPv4 Only                                                                */
1312 /* Analyze the IPv4 header and set fields in the fr_info_t structure.       */
1313 /* Check all options present and flag their presence if any exist.          */
1314 /* ------------------------------------------------------------------------ */
frpr_ipv4hdr(fin)1315 static INLINE void frpr_ipv4hdr(fin)
1316 fr_info_t *fin;
1317 {
1318 	u_short optmsk = 0, secmsk = 0, auth = 0;
1319 	int hlen, ol, mv, p, i;
1320 	const struct optlist *op;
1321 	u_char *s, opt;
1322 	u_short off;
1323 	fr_ip_t *fi;
1324 	ip_t *ip;
1325 
1326 	fi = &fin->fin_fi;
1327 	hlen = fin->fin_hlen;
1328 
1329 	ip = fin->fin_ip;
1330 	p = ip->ip_p;
1331 	fi->fi_p = p;
1332 	fi->fi_tos = ip->ip_tos;
1333 	fin->fin_id = ip->ip_id;
1334 	off = ip->ip_off;
1335 
1336 	/* Get both TTL and protocol */
1337 	fi->fi_p = ip->ip_p;
1338 	fi->fi_ttl = ip->ip_ttl;
1339 #if 0
1340 	(*(((u_short *)fi) + 1)) = (*(((u_short *)ip) + 4));
1341 #endif
1342 
1343 	/* Zero out bits not used in IPv6 address */
1344 	fi->fi_src.i6[1] = 0;
1345 	fi->fi_src.i6[2] = 0;
1346 	fi->fi_src.i6[3] = 0;
1347 	fi->fi_dst.i6[1] = 0;
1348 	fi->fi_dst.i6[2] = 0;
1349 	fi->fi_dst.i6[3] = 0;
1350 
1351 	fi->fi_saddr = ip->ip_src.s_addr;
1352 	fi->fi_daddr = ip->ip_dst.s_addr;
1353 
1354 	/*
1355 	 * set packet attribute flags based on the offset and
1356 	 * calculate the byte offset that it represents.
1357 	 */
1358 	off &= IP_MF|IP_OFFMASK;
1359 	if (off != 0) {
1360 		int morefrag = off & IP_MF;
1361 
1362 		fi->fi_flx |= FI_FRAG;
1363 		if (morefrag)
1364 			fi->fi_flx |= FI_MOREFRAG;
1365 		off &= IP_OFFMASK;
1366 		if (off != 0) {
1367 			fin->fin_flx |= FI_FRAGBODY;
1368 			off <<= 3;
1369 			if ((off + fin->fin_dlen > 65535) ||
1370 			    (fin->fin_dlen == 0) ||
1371 			    ((morefrag != 0) && ((fin->fin_dlen & 7) != 0))) {
1372 				/*
1373 				 * The length of the packet, starting at its
1374 				 * offset cannot exceed 65535 (0xffff) as the
1375 				 * length of an IP packet is only 16 bits.
1376 				 *
1377 				 * Any fragment that isn't the last fragment
1378 				 * must have a length greater than 0 and it
1379 				 * must be an even multiple of 8.
1380 				 */
1381 				fi->fi_flx |= FI_BAD;
1382 			}
1383 		}
1384 	}
1385 	fin->fin_off = off;
1386 
1387 	/*
1388 	 * Call per-protocol setup and checking
1389 	 */
1390 	switch (p)
1391 	{
1392 	case IPPROTO_UDP :
1393 		frpr_udp(fin);
1394 		break;
1395 	case IPPROTO_TCP :
1396 		frpr_tcp(fin);
1397 		break;
1398 	case IPPROTO_ICMP :
1399 		frpr_icmp(fin);
1400 		break;
1401 	case IPPROTO_AH :
1402 		frpr_ah(fin);
1403 		break;
1404 	case IPPROTO_ESP :
1405 		frpr_esp(fin);
1406 		break;
1407 	case IPPROTO_GRE :
1408 		frpr_gre(fin);
1409 		break;
1410 	}
1411 
1412 	ip = fin->fin_ip;
1413 	if (ip == NULL)
1414 		return;
1415 
1416 	/*
1417 	 * If it is a standard IP header (no options), set the flag fields
1418 	 * which relate to options to 0.
1419 	 */
1420 	if (hlen == sizeof(*ip)) {
1421 		fi->fi_optmsk = 0;
1422 		fi->fi_secmsk = 0;
1423 		fi->fi_auth = 0;
1424 		return;
1425 	}
1426 
1427 	/*
1428 	 * So the IP header has some IP options attached.  Walk the entire
1429 	 * list of options present with this packet and set flags to indicate
1430 	 * which ones are here and which ones are not.  For the somewhat out
1431 	 * of date and obscure security classification options, set a flag to
1432 	 * represent which classification is present.
1433 	 */
1434 	fi->fi_flx |= FI_OPTIONS;
1435 
1436 	for (s = (u_char *)(ip + 1), hlen -= (int)sizeof(*ip); hlen > 0; ) {
1437 		opt = *s;
1438 		if (opt == '\0')
1439 			break;
1440 		else if (opt == IPOPT_NOP)
1441 			ol = 1;
1442 		else {
1443 			if (hlen < 2)
1444 				break;
1445 			ol = (int)*(s + 1);
1446 			if (ol < 2 || ol > hlen)
1447 				break;
1448 		}
1449 		for (i = 9, mv = 4; mv >= 0; ) {
1450 			op = ipopts + i;
1451 			if ((opt == (u_char)op->ol_val) && (ol > 4)) {
1452 				optmsk |= op->ol_bit;
1453 				if (opt == IPOPT_SECURITY) {
1454 					const struct optlist *sp;
1455 					u_char	sec;
1456 					int j, m;
1457 
1458 					sec = *(s + 2);	/* classification */
1459 					for (j = 3, m = 2; m >= 0; ) {
1460 						sp = secopt + j;
1461 						if (sec == sp->ol_val) {
1462 							secmsk |= sp->ol_bit;
1463 							auth = *(s + 3);
1464 							auth *= 256;
1465 							auth += *(s + 4);
1466 							break;
1467 						}
1468 						if (sec < sp->ol_val)
1469 							j -= m;
1470 						else
1471 							j += m;
1472 						m--;
1473 					}
1474 				}
1475 				break;
1476 			}
1477 			if (opt < op->ol_val)
1478 				i -= mv;
1479 			else
1480 				i += mv;
1481 			mv--;
1482 		}
1483 		hlen -= ol;
1484 		s += ol;
1485 	}
1486 
1487 	/*
1488 	 *
1489 	 */
1490 	if (auth && !(auth & 0x0100))
1491 		auth &= 0xff00;
1492 	fi->fi_optmsk = optmsk;
1493 	fi->fi_secmsk = secmsk;
1494 	fi->fi_auth = auth;
1495 }
1496 
1497 
1498 /* ------------------------------------------------------------------------ */
1499 /* Function:    fr_makefrip                                                 */
1500 /* Returns:     int - 1 == hdr checking error, 0 == OK                      */
1501 /* Parameters:  hlen(I) - length of IP packet header                        */
1502 /*              ip(I)   - pointer to the IP header                          */
1503 /*              fin(IO) - pointer to packet information                     */
1504 /*                                                                          */
1505 /* Compact the IP header into a structure which contains just the info.     */
1506 /* which is useful for comparing IP headers with and store this information */
1507 /* in the fr_info_t structure pointer to by fin.  At present, it is assumed */
1508 /* this function will be called with either an IPv4 or IPv6 packet.         */
1509 /* ------------------------------------------------------------------------ */
fr_makefrip(hlen,ip,fin)1510 int	fr_makefrip(hlen, ip, fin)
1511 int hlen;
1512 ip_t *ip;
1513 fr_info_t *fin;
1514 {
1515 	int v;
1516 
1517 	fin->fin_depth = 0;
1518 	fin->fin_hlen = (u_short)hlen;
1519 	fin->fin_ip = ip;
1520 	fin->fin_rule = 0xffffffff;
1521 	fin->fin_group[0] = -1;
1522 	fin->fin_group[1] = '\0';
1523 	fin->fin_dlen = fin->fin_plen - hlen;
1524 	fin->fin_dp = (char *)ip + hlen;
1525 
1526 	v = fin->fin_v;
1527 	if (v == 4)
1528 		frpr_ipv4hdr(fin);
1529 #ifdef	USE_INET6
1530 	else if (v == 6)
1531 		frpr_ipv6hdr(fin);
1532 #endif
1533 	if (fin->fin_ip == NULL)
1534 		return -1;
1535 	return 0;
1536 }
1537 
1538 
1539 /* ------------------------------------------------------------------------ */
1540 /* Function:    fr_portcheck                                                */
1541 /* Returns:     int - 1 == port matched, 0 == port match failed             */
1542 /* Parameters:  frp(I) - pointer to port check `expression'                 */
1543 /*              pop(I) - pointer to port number to evaluate                 */
1544 /*                                                                          */
1545 /* Perform a comparison of a port number against some other(s), using a     */
1546 /* structure with compare information stored in it.                         */
1547 /* ------------------------------------------------------------------------ */
fr_portcheck(frp,pop)1548 static INLINE int fr_portcheck(frp, pop)
1549 frpcmp_t *frp;
1550 u_short *pop;
1551 {
1552 	u_short tup, po;
1553 	int err = 1;
1554 
1555 	tup = *pop;
1556 	po = frp->frp_port;
1557 
1558 	/*
1559 	 * Do opposite test to that required and continue if that succeeds.
1560 	 */
1561 	switch (frp->frp_cmp)
1562 	{
1563 	case FR_EQUAL :
1564 		if (tup != po) /* EQUAL */
1565 			err = 0;
1566 		break;
1567 	case FR_NEQUAL :
1568 		if (tup == po) /* NOTEQUAL */
1569 			err = 0;
1570 		break;
1571 	case FR_LESST :
1572 		if (tup >= po) /* LESSTHAN */
1573 			err = 0;
1574 		break;
1575 	case FR_GREATERT :
1576 		if (tup <= po) /* GREATERTHAN */
1577 			err = 0;
1578 		break;
1579 	case FR_LESSTE :
1580 		if (tup > po) /* LT or EQ */
1581 			err = 0;
1582 		break;
1583 	case FR_GREATERTE :
1584 		if (tup < po) /* GT or EQ */
1585 			err = 0;
1586 		break;
1587 	case FR_OUTRANGE :
1588 		if (tup >= po && tup <= frp->frp_top) /* Out of range */
1589 			err = 0;
1590 		break;
1591 	case FR_INRANGE :
1592 		if (tup <= po || tup >= frp->frp_top) /* In range */
1593 			err = 0;
1594 		break;
1595 	case FR_INCRANGE :
1596 		if (tup < po || tup > frp->frp_top) /* Inclusive range */
1597 			err = 0;
1598 		break;
1599 	default :
1600 		break;
1601 	}
1602 	return err;
1603 }
1604 
1605 
1606 /* ------------------------------------------------------------------------ */
1607 /* Function:    fr_tcpudpchk                                                */
1608 /* Returns:     int - 1 == protocol matched, 0 == check failed              */
1609 /* Parameters:  fin(I) - pointer to packet information                      */
1610 /*              ft(I)  - pointer to structure with comparison data          */
1611 /*                                                                          */
1612 /* Compares the current pcket (assuming it is TCP/UDP) information with a   */
1613 /* structure containing information that we want to match against.          */
1614 /* ------------------------------------------------------------------------ */
fr_tcpudpchk(fin,ft)1615 int fr_tcpudpchk(fin, ft)
1616 fr_info_t *fin;
1617 frtuc_t *ft;
1618 {
1619 	int err = 1;
1620 
1621 	/*
1622 	 * Both ports should *always* be in the first fragment.
1623 	 * So far, I cannot find any cases where they can not be.
1624 	 *
1625 	 * compare destination ports
1626 	 */
1627 	if (ft->ftu_dcmp)
1628 		err = fr_portcheck(&ft->ftu_dst, &fin->fin_dport);
1629 
1630 	/*
1631 	 * compare source ports
1632 	 */
1633 	if (err && ft->ftu_scmp)
1634 		err = fr_portcheck(&ft->ftu_src, &fin->fin_sport);
1635 
1636 	/*
1637 	 * If we don't have all the TCP/UDP header, then how can we
1638 	 * expect to do any sort of match on it ?  If we were looking for
1639 	 * TCP flags, then NO match.  If not, then match (which should
1640 	 * satisfy the "short" class too).
1641 	 */
1642 	if (err && (fin->fin_p == IPPROTO_TCP)) {
1643 		if (fin->fin_flx & FI_SHORT)
1644 			return !(ft->ftu_tcpf | ft->ftu_tcpfm);
1645 		/*
1646 		 * Match the flags ?  If not, abort this match.
1647 		 */
1648 		if (ft->ftu_tcpfm &&
1649 		    ft->ftu_tcpf != (fin->fin_tcpf & ft->ftu_tcpfm)) {
1650 			FR_DEBUG(("f. %#x & %#x != %#x\n", fin->fin_tcpf,
1651 				 ft->ftu_tcpfm, ft->ftu_tcpf));
1652 			err = 0;
1653 		}
1654 	}
1655 	return err;
1656 }
1657 
1658 
1659 /* ------------------------------------------------------------------------ */
1660 /* Function:    fr_ipfcheck                                                 */
1661 /* Returns:     int - 0 == match, 1 == no match                             */
1662 /* Parameters:  fin(I)     - pointer to packet information                  */
1663 /*              fr(I)      - pointer to filter rule                         */
1664 /*              portcmp(I) - flag indicating whether to attempt matching on */
1665 /*                           TCP/UDP port data.                             */
1666 /*                                                                          */
1667 /* Check to see if a packet matches an IPFilter rule.  Checks of addresses, */
1668 /* port numbers, etc, for "standard" IPFilter rules are all orchestrated in */
1669 /* this function.                                                           */
1670 /* ------------------------------------------------------------------------ */
fr_ipfcheck(fin,fr,portcmp)1671 static INLINE int fr_ipfcheck(fin, fr, portcmp)
1672 fr_info_t *fin;
1673 frentry_t *fr;
1674 int portcmp;
1675 {
1676 	u_32_t	*ld, *lm, *lip;
1677 	fripf_t *fri;
1678 	fr_ip_t *fi;
1679 	int i;
1680 	ipf_stack_t *ifs = fin->fin_ifs;
1681 
1682 	fi = &fin->fin_fi;
1683 	fri = fr->fr_ipf;
1684 	lip = (u_32_t *)fi;
1685 	lm = (u_32_t *)&fri->fri_mip;
1686 	ld = (u_32_t *)&fri->fri_ip;
1687 
1688 	/*
1689 	 * first 32 bits to check coversion:
1690 	 * IP version, TOS, TTL, protocol
1691 	 */
1692 	i = ((*lip & *lm) != *ld);
1693 	FR_DEBUG(("0. %#08x & %#08x != %#08x\n",
1694 		   *lip, *lm, *ld));
1695 	if (i)
1696 		return 1;
1697 
1698 	/*
1699 	 * Next 32 bits is a constructed bitmask indicating which IP options
1700 	 * are present (if any) in this packet.
1701 	 */
1702 	lip++, lm++, ld++;
1703 	i |= ((*lip & *lm) != *ld);
1704 	FR_DEBUG(("1. %#08x & %#08x != %#08x\n",
1705 		   *lip, *lm, *ld));
1706 	if (i)
1707 		return 1;
1708 
1709 	lip++, lm++, ld++;
1710 	/*
1711 	 * Unrolled loops (4 each, for 32 bits) for address checks.
1712 	 */
1713 	/*
1714 	 * Check the source address.
1715 	 */
1716 #ifdef	IPFILTER_LOOKUP
1717 	if (fr->fr_satype == FRI_LOOKUP) {
1718 		fin->fin_flx |= FI_DONTCACHE;
1719 		i = (*fr->fr_srcfunc)(fr->fr_srcptr, fi->fi_v, lip, fin, ifs);
1720 		if (i == -1)
1721 			return 1;
1722 		lip += 3;
1723 		lm += 3;
1724 		ld += 3;
1725 	} else {
1726 #endif
1727 		i = ((*lip & *lm) != *ld);
1728 		FR_DEBUG(("2a. %#08x & %#08x != %#08x\n",
1729 			   *lip, *lm, *ld));
1730 		if (fi->fi_v == 6) {
1731 			lip++, lm++, ld++;
1732 			i |= ((*lip & *lm) != *ld);
1733 			FR_DEBUG(("2b. %#08x & %#08x != %#08x\n",
1734 				   *lip, *lm, *ld));
1735 			lip++, lm++, ld++;
1736 			i |= ((*lip & *lm) != *ld);
1737 			FR_DEBUG(("2c. %#08x & %#08x != %#08x\n",
1738 				   *lip, *lm, *ld));
1739 			lip++, lm++, ld++;
1740 			i |= ((*lip & *lm) != *ld);
1741 			FR_DEBUG(("2d. %#08x & %#08x != %#08x\n",
1742 				   *lip, *lm, *ld));
1743 		} else {
1744 			lip += 3;
1745 			lm += 3;
1746 			ld += 3;
1747 		}
1748 #ifdef	IPFILTER_LOOKUP
1749 	}
1750 #endif
1751 	i ^= (fr->fr_flags & FR_NOTSRCIP) >> 6;
1752 	if (i)
1753 		return 1;
1754 
1755 	/*
1756 	 * Check the destination address.
1757 	 */
1758 	lip++, lm++, ld++;
1759 #ifdef	IPFILTER_LOOKUP
1760 	if (fr->fr_datype == FRI_LOOKUP) {
1761 		fin->fin_flx |= FI_DONTCACHE;
1762 		i = (*fr->fr_dstfunc)(fr->fr_dstptr, fi->fi_v, lip, fin, ifs);
1763 		if (i == -1)
1764 			return 1;
1765 		lip += 3;
1766 		lm += 3;
1767 		ld += 3;
1768 	} else {
1769 #endif
1770 		i = ((*lip & *lm) != *ld);
1771 		FR_DEBUG(("3a. %#08x & %#08x != %#08x\n",
1772 			   *lip, *lm, *ld));
1773 		if (fi->fi_v == 6) {
1774 			lip++, lm++, ld++;
1775 			i |= ((*lip & *lm) != *ld);
1776 			FR_DEBUG(("3b. %#08x & %#08x != %#08x\n",
1777 				   *lip, *lm, *ld));
1778 			lip++, lm++, ld++;
1779 			i |= ((*lip & *lm) != *ld);
1780 			FR_DEBUG(("3c. %#08x & %#08x != %#08x\n",
1781 				   *lip, *lm, *ld));
1782 			lip++, lm++, ld++;
1783 			i |= ((*lip & *lm) != *ld);
1784 			FR_DEBUG(("3d. %#08x & %#08x != %#08x\n",
1785 				   *lip, *lm, *ld));
1786 		} else {
1787 			lip += 3;
1788 			lm += 3;
1789 			ld += 3;
1790 		}
1791 #ifdef	IPFILTER_LOOKUP
1792 	}
1793 #endif
1794 	i ^= (fr->fr_flags & FR_NOTDSTIP) >> 7;
1795 	if (i)
1796 		return 1;
1797 	/*
1798 	 * IP addresses matched.  The next 32bits contains:
1799 	 * mast of old IP header security & authentication bits.
1800 	 */
1801 	lip++, lm++, ld++;
1802 	i |= ((*lip & *lm) != *ld);
1803 	FR_DEBUG(("4. %#08x & %#08x != %#08x\n",
1804 		   *lip, *lm, *ld));
1805 
1806 	/*
1807 	 * Next we have 32 bits of packet flags.
1808 	 */
1809 	lip++, lm++, ld++;
1810 	i |= ((*lip & *lm) != *ld);
1811 	FR_DEBUG(("5. %#08x & %#08x != %#08x\n",
1812 		   *lip, *lm, *ld));
1813 
1814 	if (i == 0) {
1815 		/*
1816 		 * If a fragment, then only the first has what we're
1817 		 * looking for here...
1818 		 */
1819 		if (portcmp) {
1820 			if (!fr_tcpudpchk(fin, &fr->fr_tuc))
1821 				i = 1;
1822 		} else {
1823 			if (fr->fr_dcmp || fr->fr_scmp ||
1824 			    fr->fr_tcpf || fr->fr_tcpfm)
1825 				i = 1;
1826 			if (fr->fr_icmpm || fr->fr_icmp) {
1827 				if (((fi->fi_p != IPPROTO_ICMP) &&
1828 				     (fi->fi_p != IPPROTO_ICMPV6)) ||
1829 				    fin->fin_off || (fin->fin_dlen < 2))
1830 					i = 1;
1831 				else if ((fin->fin_data[0] & fr->fr_icmpm) !=
1832 					 fr->fr_icmp) {
1833 					FR_DEBUG(("i. %#x & %#x != %#x\n",
1834 						 fin->fin_data[0],
1835 						 fr->fr_icmpm, fr->fr_icmp));
1836 					i = 1;
1837 				}
1838 			}
1839 		}
1840 	}
1841 	return i;
1842 }
1843 
1844 
1845 /* ------------------------------------------------------------------------ */
1846 /* Function:    fr_scanlist                                                 */
1847 /* Returns:     int - result flags of scanning filter list                  */
1848 /* Parameters:  fin(I) - pointer to packet information                      */
1849 /*              pass(I) - default result to return for filtering            */
1850 /*                                                                          */
1851 /* Check the input/output list of rules for a match to the current packet.  */
1852 /* If a match is found, the value of fr_flags from the rule becomes the     */
1853 /* return value and fin->fin_fr points to the matched rule.                 */
1854 /*                                                                          */
1855 /* This function may be called recusively upto 16 times (limit inbuilt.)    */
1856 /* When unwinding, it should finish up with fin_depth as 0.                 */
1857 /*                                                                          */
1858 /* Could be per interface, but this gets real nasty when you don't have,    */
1859 /* or can't easily change, the kernel source code to .                      */
1860 /* ------------------------------------------------------------------------ */
fr_scanlist(fin,pass)1861 int fr_scanlist(fin, pass)
1862 fr_info_t *fin;
1863 u_32_t pass;
1864 {
1865 	int rulen, portcmp, off, logged, skip;
1866 	struct frentry *fr, *fnext;
1867 	u_32_t passt, passo;
1868 	ipf_stack_t *ifs = fin->fin_ifs;
1869 
1870 	/*
1871 	 * Do not allow nesting deeper than 16 levels.
1872 	 */
1873 	if (fin->fin_depth >= 16)
1874 		return pass;
1875 
1876 	fr = fin->fin_fr;
1877 
1878 	/*
1879 	 * If there are no rules in this list, return now.
1880 	 */
1881 	if (fr == NULL)
1882 		return pass;
1883 
1884 	skip = 0;
1885 	logged = 0;
1886 	portcmp = 0;
1887 	fin->fin_depth++;
1888 	fin->fin_fr = NULL;
1889 	off = fin->fin_off;
1890 
1891 	if ((fin->fin_flx & FI_TCPUDP) && (fin->fin_dlen > 3) && !off)
1892 		portcmp = 1;
1893 
1894 	for (rulen = 0; fr; fr = fnext, rulen++) {
1895 		fnext = fr->fr_next;
1896 		if (skip != 0) {
1897 			FR_VERBOSE(("%d (%#x)\n", skip, fr->fr_flags));
1898 			skip--;
1899 			continue;
1900 		}
1901 
1902 		/*
1903 		 * In all checks below, a null (zero) value in the
1904 		 * filter struture is taken to mean a wildcard.
1905 		 *
1906 		 * check that we are working for the right interface
1907 		 */
1908 #ifdef	_KERNEL
1909 		if (fr->fr_ifa && fr->fr_ifa != fin->fin_ifp)
1910 			continue;
1911 #else
1912 		if (opts & (OPT_VERBOSE|OPT_DEBUG))
1913 			printf("\n");
1914 		FR_VERBOSE(("%c", FR_ISSKIP(pass) ? 's' :
1915 				  FR_ISPASS(pass) ? 'p' :
1916 				  FR_ISACCOUNT(pass) ? 'A' :
1917 				  FR_ISAUTH(pass) ? 'a' :
1918 				  (pass & FR_NOMATCH) ? 'n' :'b'));
1919 		if (fr->fr_ifa && fr->fr_ifa != fin->fin_ifp)
1920 			continue;
1921 		FR_VERBOSE((":i"));
1922 #endif
1923 
1924 		switch (fr->fr_type)
1925 		{
1926 		case FR_T_IPF :
1927 		case FR_T_IPF|FR_T_BUILTIN :
1928 			if (fr_ipfcheck(fin, fr, portcmp))
1929 				continue;
1930 			break;
1931 #if defined(IPFILTER_BPF)
1932 		case FR_T_BPFOPC :
1933 		case FR_T_BPFOPC|FR_T_BUILTIN :
1934 		    {
1935 			u_char *mc;
1936 
1937 			if (*fin->fin_mp == NULL)
1938 				continue;
1939 			if (fin->fin_v != fr->fr_v)
1940 				continue;
1941 			mc = (u_char *)fin->fin_m;
1942 			if (!bpf_filter(fr->fr_data, mc, fin->fin_plen, 0))
1943 				continue;
1944 			break;
1945 		    }
1946 #endif
1947 		case FR_T_CALLFUNC|FR_T_BUILTIN :
1948 		    {
1949 			frentry_t *f;
1950 
1951 			f = (*fr->fr_func)(fin, &pass);
1952 			if (f != NULL)
1953 				fr = f;
1954 			else
1955 				continue;
1956 			break;
1957 		    }
1958 		default :
1959 			break;
1960 		}
1961 
1962 		if ((fin->fin_out == 0) && (fr->fr_nattag.ipt_num[0] != 0)) {
1963 			if (fin->fin_nattag == NULL)
1964 				continue;
1965 			if (fr_matchtag(&fr->fr_nattag, fin->fin_nattag) == 0)
1966 				continue;
1967 		}
1968 		FR_VERBOSE(("=%s.%d *", fr->fr_group, rulen));
1969 
1970 		passt = fr->fr_flags;
1971 
1972 		/*
1973 		 * Allowing a rule with the "keep state" flag set to match
1974 		 * packets that have been tagged "out of window" by the TCP
1975 		 * state tracking is foolish as the attempt to add a new
1976 		 * state entry to the table will fail.
1977 		 */
1978 		if ((passt & FR_KEEPSTATE) && (fin->fin_flx & FI_OOW))
1979 			continue;
1980 
1981 		/*
1982 		 * If the rule is a "call now" rule, then call the function
1983 		 * in the rule, if it exists and use the results from that.
1984 		 * If the function pointer is bad, just make like we ignore
1985 		 * it, except for increasing the hit counter.
1986 		 */
1987 		IPF_BUMP(fr->fr_hits);
1988 		fr->fr_bytes += (U_QUAD_T)fin->fin_plen;
1989 		if ((passt & FR_CALLNOW) != 0) {
1990 			if ((fr->fr_func != NULL) &&
1991 			    (fr->fr_func != (ipfunc_t)-1)) {
1992 				frentry_t *frs;
1993 
1994 				frs = fin->fin_fr;
1995 				fin->fin_fr = fr;
1996 				fr = (*fr->fr_func)(fin, &passt);
1997 				if (fr == NULL) {
1998 					fin->fin_fr = frs;
1999 					continue;
2000 				}
2001 				passt = fr->fr_flags;
2002 				fin->fin_fr = fr;
2003 			}
2004 		} else {
2005 			fin->fin_fr = fr;
2006 		}
2007 
2008 #ifdef  IPFILTER_LOG
2009 		/*
2010 		 * Just log this packet...
2011 		 */
2012 		if ((passt & FR_LOGMASK) == FR_LOG) {
2013 			if (ipflog(fin, passt) == -1) {
2014 				if (passt & FR_LOGORBLOCK) {
2015 					passt &= ~FR_CMDMASK;
2016 					passt |= FR_BLOCK|FR_QUICK;
2017 				}
2018 				IPF_BUMP(ifs->ifs_frstats[fin->fin_out].fr_skip);
2019 			}
2020 			IPF_BUMP(ifs->ifs_frstats[fin->fin_out].fr_pkl);
2021 			logged = 1;
2022 		}
2023 #endif /* IPFILTER_LOG */
2024 		passo = pass;
2025 		if (FR_ISSKIP(passt))
2026 			skip = fr->fr_arg;
2027 		else if ((passt & FR_LOGMASK) != FR_LOG)
2028 			pass = passt;
2029 		if (passt & (FR_RETICMP|FR_FAKEICMP))
2030 			fin->fin_icode = fr->fr_icode;
2031 		FR_DEBUG(("pass %#x\n", pass));
2032 		fin->fin_rule = rulen;
2033 		(void) strncpy(fin->fin_group, fr->fr_group, FR_GROUPLEN);
2034 		if (fr->fr_grp != NULL) {
2035 			fin->fin_fr = *fr->fr_grp;
2036 			pass = fr_scanlist(fin, pass);
2037 			if (fin->fin_fr == NULL) {
2038 				fin->fin_rule = rulen;
2039 				(void) strncpy(fin->fin_group, fr->fr_group,
2040 					       FR_GROUPLEN);
2041 				fin->fin_fr = fr;
2042 			}
2043 			if (fin->fin_flx & FI_DONTCACHE)
2044 				logged = 1;
2045 		}
2046 
2047 		if (pass & FR_QUICK) {
2048 			/*
2049 			 * Finally, if we've asked to track state for this
2050 			 * packet, set it up.  Add state for "quick" rules
2051 			 * here so that if the action fails we can consider
2052 			 * the rule to "not match" and keep on processing
2053 			 * filter rules.
2054 			 */
2055 			if ((pass & FR_KEEPSTATE) &&
2056 			    !(fin->fin_flx & FI_STATE)) {
2057 				int out = fin->fin_out;
2058 
2059 				if (fr_addstate(fin, NULL, 0) != NULL) {
2060 					IPF_BUMP(ifs->ifs_frstats[out].fr_ads);
2061 				} else {
2062 					IPF_BUMP(ifs->ifs_frstats[out].fr_bads);
2063 					pass = passo;
2064 					continue;
2065 				}
2066 			}
2067 			break;
2068 		}
2069 	}
2070 	if (logged)
2071 		fin->fin_flx |= FI_DONTCACHE;
2072 	fin->fin_depth--;
2073 	return pass;
2074 }
2075 
2076 
2077 /* ------------------------------------------------------------------------ */
2078 /* Function:    fr_acctpkt                                                  */
2079 /* Returns:     frentry_t* - always returns NULL                            */
2080 /* Parameters:  fin(I) - pointer to packet information                      */
2081 /*              passp(IO) - pointer to current/new filter decision (unused) */
2082 /*                                                                          */
2083 /* Checks a packet against accounting rules, if there are any for the given */
2084 /* IP protocol version.                                                     */
2085 /*                                                                          */
2086 /* N.B.: this function returns NULL to match the prototype used by other    */
2087 /* functions called from the IPFilter "mainline" in fr_check().             */
2088 /* ------------------------------------------------------------------------ */
fr_acctpkt(fin,passp)2089 frentry_t *fr_acctpkt(fin, passp)
2090 fr_info_t *fin;
2091 u_32_t *passp;
2092 {
2093 	char group[FR_GROUPLEN];
2094 	frentry_t *fr, *frsave;
2095 	u_32_t pass, rulen;
2096 	ipf_stack_t *ifs = fin->fin_ifs;
2097 
2098 	passp = passp;
2099 #ifdef	USE_INET6
2100 	if (fin->fin_v == 6)
2101 		fr = ifs->ifs_ipacct6[fin->fin_out][ifs->ifs_fr_active];
2102 	else
2103 #endif
2104 		fr = ifs->ifs_ipacct[fin->fin_out][ifs->ifs_fr_active];
2105 
2106 	if (fr != NULL) {
2107 		frsave = fin->fin_fr;
2108 		bcopy(fin->fin_group, group, FR_GROUPLEN);
2109 		rulen = fin->fin_rule;
2110 		fin->fin_fr = fr;
2111 		pass = fr_scanlist(fin, FR_NOMATCH);
2112 		if (FR_ISACCOUNT(pass)) {
2113 			IPF_BUMP(ifs->ifs_frstats[0].fr_acct);
2114 		}
2115 		fin->fin_fr = frsave;
2116 		bcopy(group, fin->fin_group, FR_GROUPLEN);
2117 		fin->fin_rule = rulen;
2118 	}
2119 	return NULL;
2120 }
2121 
2122 
2123 /* ------------------------------------------------------------------------ */
2124 /* Function:    fr_firewall                                                 */
2125 /* Returns:     frentry_t* - returns pointer to matched rule, if no matches */
2126 /*                           were found, returns NULL.                      */
2127 /* Parameters:  fin(I) - pointer to packet information                      */
2128 /*              passp(IO) - pointer to current/new filter decision (unused) */
2129 /*                                                                          */
2130 /* Applies an appropriate set of firewall rules to the packet, to see if    */
2131 /* there are any matches.  The first check is to see if a match can be seen */
2132 /* in the cache.  If not, then search an appropriate list of rules.  Once a */
2133 /* matching rule is found, take any appropriate actions as defined by the   */
2134 /* rule - except logging.                                                   */
2135 /* ------------------------------------------------------------------------ */
fr_firewall(fin,passp)2136 static frentry_t *fr_firewall(fin, passp)
2137 fr_info_t *fin;
2138 u_32_t *passp;
2139 {
2140 	frentry_t *fr;
2141 	fr_info_t *fc;
2142 	u_32_t pass;
2143 	int out;
2144 	ipf_stack_t *ifs = fin->fin_ifs;
2145 
2146 	out = fin->fin_out;
2147 	pass = *passp;
2148 
2149 #ifdef	USE_INET6
2150 	if (fin->fin_v == 6)
2151 		fin->fin_fr = ifs->ifs_ipfilter6[out][ifs->ifs_fr_active];
2152 	else
2153 #endif
2154 		fin->fin_fr = ifs->ifs_ipfilter[out][ifs->ifs_fr_active];
2155 
2156 	/*
2157 	 * If there are no rules loaded skip all checks and return.
2158 	 */
2159 	if (fin->fin_fr == NULL) {
2160 
2161 		if ((pass & FR_NOMATCH)) {
2162 			IPF_BUMP(ifs->ifs_frstats[out].fr_nom);
2163 		}
2164 
2165 		return (NULL);
2166 	}
2167 
2168 	fc = &ifs->ifs_frcache[out][CACHE_HASH(fin)];
2169 	READ_ENTER(&ifs->ifs_ipf_frcache);
2170 	if (!bcmp((char *)fin, (char *)fc, FI_CSIZE)) {
2171 		/*
2172 		 * copy cached data so we can unlock the mutexes earlier.
2173 		 */
2174 		bcopy((char *)fc, (char *)fin, FI_COPYSIZE);
2175 		RWLOCK_EXIT(&ifs->ifs_ipf_frcache);
2176 		IPF_BUMP(ifs->ifs_frstats[out].fr_chit);
2177 
2178 		if ((fr = fin->fin_fr) != NULL) {
2179 			IPF_BUMP(fr->fr_hits);
2180 			fr->fr_bytes += (U_QUAD_T)fin->fin_plen;
2181 			pass = fr->fr_flags;
2182 		}
2183 	} else {
2184 		RWLOCK_EXIT(&ifs->ifs_ipf_frcache);
2185 
2186 		pass = fr_scanlist(fin, ifs->ifs_fr_pass);
2187 
2188 		if (((pass & FR_KEEPSTATE) == 0) &&
2189 		    ((fin->fin_flx & FI_DONTCACHE) == 0)) {
2190 			WRITE_ENTER(&ifs->ifs_ipf_frcache);
2191 			bcopy((char *)fin, (char *)fc, FI_COPYSIZE);
2192 			RWLOCK_EXIT(&ifs->ifs_ipf_frcache);
2193 		}
2194 
2195 		fr = fin->fin_fr;
2196 	}
2197 
2198 	if ((pass & FR_NOMATCH)) {
2199 		IPF_BUMP(ifs->ifs_frstats[out].fr_nom);
2200 	}
2201 
2202 	/*
2203 	 * Apply packets per second rate-limiting to a rule as required.
2204 	 */
2205 	if ((fr != NULL) && (fr->fr_pps != 0) &&
2206 	    !ppsratecheck(&fr->fr_lastpkt, &fr->fr_curpps, fr->fr_pps)) {
2207 		pass &= ~(FR_CMDMASK|FR_DUP|FR_RETICMP|FR_RETRST);
2208 		pass |= FR_BLOCK;
2209 		IPF_BUMP(ifs->ifs_frstats[out].fr_ppshit);
2210 	}
2211 
2212 	/*
2213 	 * If we fail to add a packet to the authorization queue, then we
2214 	 * drop the packet later.  However, if it was added then pretend
2215 	 * we've dropped it already.
2216 	 */
2217 	if (FR_ISAUTH(pass)) {
2218 		if (fr_newauth(fin->fin_m, fin) != 0) {
2219 #ifdef	_KERNEL
2220 			fin->fin_m = *fin->fin_mp = NULL;
2221 #else
2222 			;
2223 #endif
2224 			fin->fin_error = 0;
2225 		} else
2226 			fin->fin_error = ENOSPC;
2227 	}
2228 
2229 	if ((fr != NULL) && (fr->fr_func != NULL) &&
2230 	    (fr->fr_func != (ipfunc_t)-1) && !(pass & FR_CALLNOW))
2231 		(void) (*fr->fr_func)(fin, &pass);
2232 
2233 	/*
2234 	 * If a rule is a pre-auth rule, check again in the list of rules
2235 	 * loaded for authenticated use.  It does not particulary matter
2236 	 * if this search fails because a "preauth" result, from a rule,
2237 	 * is treated as "not a pass", hence the packet is blocked.
2238 	 */
2239 	if (FR_ISPREAUTH(pass)) {
2240 		if ((fin->fin_fr = ifs->ifs_ipauth) != NULL)
2241 			pass = fr_scanlist(fin, ifs->ifs_fr_pass);
2242 	}
2243 
2244 	/*
2245 	 * If the rule has "keep frag" and the packet is actually a fragment,
2246 	 * then create a fragment state entry.
2247 	 */
2248 	if ((pass & (FR_KEEPFRAG|FR_KEEPSTATE)) == FR_KEEPFRAG) {
2249 		if (fin->fin_flx & FI_FRAG) {
2250 			if (fr_newfrag(fin, pass) == -1) {
2251 				IPF_BUMP(ifs->ifs_frstats[out].fr_bnfr);
2252 			} else {
2253 				IPF_BUMP(ifs->ifs_frstats[out].fr_nfr);
2254 			}
2255 		} else {
2256 			IPF_BUMP(ifs->ifs_frstats[out].fr_cfr);
2257 		}
2258 	}
2259 
2260 	/*
2261 	 * Finally, if we've asked to track state for this packet, set it up.
2262 	 */
2263 	if ((pass & FR_KEEPSTATE) && !(fin->fin_flx & FI_STATE)) {
2264 		if (fr_addstate(fin, NULL, 0) != NULL) {
2265 			IPF_BUMP(ifs->ifs_frstats[out].fr_ads);
2266 		} else {
2267 			IPF_BUMP(ifs->ifs_frstats[out].fr_bads);
2268 			if (FR_ISPASS(pass)) {
2269 				pass &= ~FR_CMDMASK;
2270 				pass |= FR_BLOCK;
2271 			}
2272 		}
2273 	}
2274 
2275 	fr = fin->fin_fr;
2276 
2277 	if (passp != NULL)
2278 		*passp = pass;
2279 
2280 	return fr;
2281 }
2282 
2283 /* ------------------------------------------------------------------------ */
2284 /* Function:    fr_check                                                    */
2285 /* Returns:     int -  0 == packet allowed through,                         */
2286 /*              User space:                                                 */
2287 /*                    -1 == packet blocked                                  */
2288 /*                     1 == packet not matched                              */
2289 /*                    -2 == requires authentication                         */
2290 /*              Kernel:                                                     */
2291 /*                   > 0 == filter error # for packet                       */
2292 /* Parameters: ip(I)   - pointer to start of IPv4/6 packet                  */
2293 /*             hlen(I) - length of header                                   */
2294 /*             ifp(I)  - pointer to interface this packet is on             */
2295 /*             out(I)  - 0 == packet going in, 1 == packet going out        */
2296 /*             mp(IO)  - pointer to caller's buffer pointer that holds this */
2297 /*                       IP packet.                                         */
2298 /* Solaris & HP-UX ONLY :                                                   */
2299 /*             qpi(I)  - pointer to STREAMS queue information for this      */
2300 /*                       interface & direction.                             */
2301 /*                                                                          */
2302 /* fr_check() is the master function for all IPFilter packet processing.    */
2303 /* It orchestrates: Network Address Translation (NAT), checking for packet  */
2304 /* authorisation (or pre-authorisation), presence of related state info.,   */
2305 /* generating log entries, IP packet accounting, routing of packets as      */
2306 /* directed by firewall rules and of course whether or not to allow the     */
2307 /* packet to be further processed by the kernel.                            */
2308 /*                                                                          */
2309 /* For packets blocked, the contents of "mp" will be NULL'd and the buffer  */
2310 /* freed.  Packets passed may be returned with the pointer pointed to by    */
2311 /* by "mp" changed to a new buffer.                                         */
2312 /* ------------------------------------------------------------------------ */
fr_check(ip,hlen,ifp,out,qif,mp,ifs)2313 int fr_check(ip, hlen, ifp, out
2314 #if defined(_KERNEL) && defined(MENTAT)
2315 , qif, mp, ifs)
2316 void *qif;
2317 #else
2318 , mp, ifs)
2319 #endif
2320 mb_t **mp;
2321 ip_t *ip;
2322 int hlen;
2323 void *ifp;
2324 int out;
2325 ipf_stack_t *ifs;
2326 {
2327 	/*
2328 	 * The above really sucks, but short of writing a diff
2329 	 */
2330 	fr_info_t frinfo;
2331 	fr_info_t *fin = &frinfo;
2332 	u_32_t pass;
2333 	frentry_t *fr = NULL;
2334 	int v = IP_V(ip);
2335 	mb_t *mc = NULL;
2336 	mb_t *m;
2337 #ifdef USE_INET6
2338 	ip6_t *ip6;
2339 #endif
2340 #ifdef	_KERNEL
2341 # ifdef MENTAT
2342 	qpktinfo_t *qpi = qif;
2343 #endif
2344 #endif
2345 
2346 	SPL_INT(s);
2347 	pass = ifs->ifs_fr_pass;
2348 
2349 	/*
2350 	 * The first part of fr_check() deals with making sure that what goes
2351 	 * into the filtering engine makes some sense.  Information about the
2352 	 * the packet is distilled, collected into a fr_info_t structure and
2353 	 * the an attempt to ensure the buffer the packet is in is big enough
2354 	 * to hold all the required packet headers.
2355 	 */
2356 #ifdef	_KERNEL
2357 # ifdef MENTAT
2358 	if (!OK_32PTR(ip))
2359 		return 2;
2360 # endif
2361 
2362 
2363 	if (ifs->ifs_fr_running <= 0) {
2364 		return 0;
2365 	}
2366 
2367 	bzero((char *)fin, sizeof(*fin));
2368 
2369 # ifdef MENTAT
2370 	fin->fin_flx = qpi->qpi_flags & (FI_NOCKSUM|FI_MBCAST|FI_MULTICAST|
2371 					 FI_BROADCAST);
2372 	m = qpi->qpi_m;
2373 	fin->fin_qfm = m;
2374 	fin->fin_qpi = qpi;
2375 # else /* MENTAT */
2376 
2377 	m = *mp;
2378 
2379 #  if defined(M_MCAST)
2380 	if ((m->m_flags & M_MCAST) != 0)
2381 		fin->fin_flx |= FI_MBCAST|FI_MULTICAST;
2382 #  endif
2383 #  if defined(M_MLOOP)
2384 	if ((m->m_flags & M_MLOOP) != 0)
2385 		fin->fin_flx |= FI_MBCAST|FI_MULTICAST;
2386 #  endif
2387 #  if defined(M_BCAST)
2388 	if ((m->m_flags & M_BCAST) != 0)
2389 		fin->fin_flx |= FI_MBCAST|FI_BROADCAST;
2390 #  endif
2391 #  ifdef M_CANFASTFWD
2392 	/*
2393 	 * XXX For now, IP Filter and fast-forwarding of cached flows
2394 	 * XXX are mutually exclusive.  Eventually, IP Filter should
2395 	 * XXX get a "can-fast-forward" filter rule.
2396 	 */
2397 	m->m_flags &= ~M_CANFASTFWD;
2398 #  endif /* M_CANFASTFWD */
2399 #  ifdef CSUM_DELAY_DATA
2400 	/*
2401 	 * disable delayed checksums.
2402 	 */
2403 	if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
2404 		in_delayed_cksum(m);
2405 		m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
2406 	}
2407 #  endif /* CSUM_DELAY_DATA */
2408 # endif /* MENTAT */
2409 #else
2410 
2411 	bzero((char *)fin, sizeof(*fin));
2412 	m = *mp;
2413 #endif /* _KERNEL */
2414 
2415 	fin->fin_v = v;
2416 	fin->fin_m = m;
2417 	fin->fin_ip = ip;
2418 	fin->fin_mp = mp;
2419 	fin->fin_out = out;
2420 	fin->fin_ifp = ifp;
2421 	fin->fin_error = ENETUNREACH;
2422 	fin->fin_hlen = (u_short)hlen;
2423 	fin->fin_dp = (char *)ip + hlen;
2424 	fin->fin_ipoff = (char *)ip - MTOD(m, char *);
2425 	fin->fin_ifs = ifs;
2426 
2427 	SPL_NET(s);
2428 
2429 #ifdef	USE_INET6
2430 	if (v == 6) {
2431 		IPF_BUMP(ifs->ifs_frstats[out].fr_ipv6);
2432 		/*
2433 		 * Jumbo grams are quite likely too big for internal buffer
2434 		 * structures to handle comfortably, for now, so just drop
2435 		 * them.
2436 		 */
2437 		ip6 = (ip6_t *)ip;
2438 		fin->fin_plen = ntohs(ip6->ip6_plen);
2439 		if (fin->fin_plen == 0) {
2440 			READ_ENTER(&ifs->ifs_ipf_mutex);
2441 			pass = FR_BLOCK|FR_NOMATCH;
2442 			goto filtered;
2443 		}
2444 		fin->fin_plen += sizeof(ip6_t);
2445 	} else
2446 #endif
2447 	{
2448 #if (OpenBSD >= 200311) && defined(_KERNEL)
2449 		ip->ip_len = ntohs(ip->ip_len);
2450 		ip->ip_off = ntohs(ip->ip_off);
2451 #endif
2452 		fin->fin_plen = ip->ip_len;
2453 	}
2454 
2455 	if (fr_makefrip(hlen, ip, fin) == -1) {
2456 		READ_ENTER(&ifs->ifs_ipf_mutex);
2457 		pass = FR_BLOCK;
2458 		goto filtered;
2459 	}
2460 
2461 	/*
2462 	 * For at least IPv6 packets, if a m_pullup() fails then this pointer
2463 	 * becomes NULL and so we have no packet to free.
2464 	 */
2465 	if (*fin->fin_mp == NULL)
2466 		goto finished;
2467 
2468 	if (!out) {
2469 		if (v == 4) {
2470 #ifdef _KERNEL
2471 			if (ifs->ifs_fr_chksrc && !fr_verifysrc(fin)) {
2472 				IPF_BUMP(ifs->ifs_frstats[0].fr_badsrc);
2473 				fin->fin_flx |= FI_BADSRC;
2474 			}
2475 #endif
2476 			if (fin->fin_ip->ip_ttl < ifs->ifs_fr_minttl) {
2477 				IPF_BUMP(ifs->ifs_frstats[0].fr_badttl);
2478 				fin->fin_flx |= FI_LOWTTL;
2479 			}
2480 		}
2481 #ifdef USE_INET6
2482 		else  if (v == 6) {
2483 			ip6 = (ip6_t *)ip;
2484 #ifdef _KERNEL
2485 			if (ifs->ifs_fr_chksrc && !fr_verifysrc(fin)) {
2486 				IPF_BUMP(ifs->ifs_frstats[0].fr_badsrc);
2487 				fin->fin_flx |= FI_BADSRC;
2488 			}
2489 #endif
2490 			if (ip6->ip6_hlim < ifs->ifs_fr_minttl) {
2491 				IPF_BUMP(ifs->ifs_frstats[0].fr_badttl);
2492 				fin->fin_flx |= FI_LOWTTL;
2493 			}
2494 		}
2495 #endif
2496 	}
2497 
2498 	if (fin->fin_flx & FI_SHORT) {
2499 		IPF_BUMP(ifs->ifs_frstats[out].fr_short);
2500 	}
2501 
2502 	READ_ENTER(&ifs->ifs_ipf_mutex);
2503 
2504 	/*
2505 	 * Check auth now.  This, combined with the check below to see if apass
2506 	 * is 0 is to ensure that we don't count the packet twice, which can
2507 	 * otherwise occur when we reprocess it.  As it is, we only count it
2508 	 * after it has no auth. table matchup.  This also stops NAT from
2509 	 * occuring until after the packet has been auth'd.
2510 	 */
2511 	fr = fr_checkauth(fin, &pass);
2512 	if (!out) {
2513 		switch (fin->fin_v)
2514 		{
2515 		case 4 :
2516 			if (fr_checknatin(fin, &pass) == -1) {
2517 				RWLOCK_EXIT(&ifs->ifs_ipf_mutex);
2518 				goto finished;
2519 			}
2520 			break;
2521 #ifdef	USE_INET6
2522 		case 6 :
2523 			if (fr_checknat6in(fin, &pass) == -1) {
2524 				RWLOCK_EXIT(&ifs->ifs_ipf_mutex);
2525 				goto finished;
2526 			}
2527 			break;
2528 #endif
2529 		default :
2530 			break;
2531 		}
2532 	}
2533 	if (!out)
2534 		(void) fr_acctpkt(fin, NULL);
2535 
2536 	if (fr == NULL)
2537 		if ((fin->fin_flx & (FI_FRAG|FI_BAD)) == FI_FRAG)
2538 			fr = fr_knownfrag(fin, &pass);
2539 	if (fr == NULL)
2540 		fr = fr_checkstate(fin, &pass);
2541 
2542 	if ((pass & FR_NOMATCH) || (fr == NULL))
2543 		fr = fr_firewall(fin, &pass);
2544 
2545 	fin->fin_fr = fr;
2546 
2547 	/*
2548 	 * Only count/translate packets which will be passed on, out the
2549 	 * interface.
2550 	 */
2551 	if (out && FR_ISPASS(pass)) {
2552 		(void) fr_acctpkt(fin, NULL);
2553 
2554 		switch (fin->fin_v)
2555 		{
2556 		case 4 :
2557 			if (fr_checknatout(fin, &pass) == -1) {
2558 				RWLOCK_EXIT(&ifs->ifs_ipf_mutex);
2559 				goto finished;
2560 			}
2561 			break;
2562 #ifdef	USE_INET6
2563 		case 6 :
2564 			if (fr_checknat6out(fin, &pass) == -1) {
2565 				RWLOCK_EXIT(&ifs->ifs_ipf_mutex);
2566 				goto finished;
2567 			}
2568 			break;
2569 #endif
2570 		default :
2571 			break;
2572 		}
2573 
2574 		if ((ifs->ifs_fr_update_ipid != 0) && (v == 4)) {
2575 			if (fr_updateipid(fin) == -1) {
2576 				IPF_BUMP(ifs->ifs_frstats[1].fr_ipud);
2577 				pass &= ~FR_CMDMASK;
2578 				pass |= FR_BLOCK;
2579 			} else {
2580 				IPF_BUMP(ifs->ifs_frstats[0].fr_ipud);
2581 			}
2582 		}
2583 	}
2584 
2585 #ifdef	IPFILTER_LOG
2586 	if ((ifs->ifs_fr_flags & FF_LOGGING) || (pass & FR_LOGMASK)) {
2587 		(void) fr_dolog(fin, &pass);
2588 	}
2589 #endif
2590 
2591 	/*
2592 	 * The FI_STATE flag is cleared here so that calling fr_checkstate
2593 	 * will work when called from inside of fr_fastroute.  Although
2594 	 * there is a similar flag, FI_NATED, for NAT, it does have the same
2595 	 * impact on code execution.
2596 	 */
2597 	fin->fin_flx &= ~FI_STATE;
2598 
2599 	/*
2600 	 * Only allow FR_DUP to work if a rule matched - it makes no sense to
2601 	 * set FR_DUP as a "default" as there are no instructions about where
2602 	 * to send the packet.  Use fin_m here because it may have changed
2603 	 * (without an update of 'm') in prior processing.
2604 	 */
2605 	if ((fr != NULL) && (pass & FR_DUP)) {
2606 		mc = M_DUPLICATE(fin->fin_m);
2607 #ifdef _KERNEL
2608 		mc->b_rptr += fin->fin_ipoff;
2609 #endif
2610 	}
2611 
2612 	/*
2613 	 * We don't want to send RST for packets, which are going to be
2614 	 * dropped, just because they don't fit into TCP window. Those packets
2615 	 * will be dropped silently. In other words, we want to drop packet,
2616 	 * while keeping session alive.
2617 	 */
2618 	if ((pass & (FR_RETRST|FR_RETICMP)) && ((fin->fin_flx & FI_OOW) == 0)) {
2619 		/*
2620 		 * Should we return an ICMP packet to indicate error
2621 		 * status passing through the packet filter ?
2622 		 * WARNING: ICMP error packets AND TCP RST packets should
2623 		 * ONLY be sent in repsonse to incoming packets.  Sending them
2624 		 * in response to outbound packets can result in a panic on
2625 		 * some operating systems.
2626 		 */
2627 		if (!out) {
2628 			if (pass & FR_RETICMP) {
2629 				int dst;
2630 
2631 				if ((pass & FR_RETMASK) == FR_FAKEICMP)
2632 					dst = 1;
2633 				else
2634 					dst = 0;
2635 #if defined(_KERNEL) && (SOLARIS2 >= 10)
2636 				/*
2637 				 * Assume it's possible to enter insane rule:
2638 				 * 	pass return-icmp in proto udp ...
2639 				 * then we have no other option than to forward
2640 				 * packet on loopback and give up any attempt
2641 				 * to create a fake response.
2642 				 */
2643 				if (IPF_IS_LOOPBACK(qpi->qpi_flags) &&
2644 				    FR_ISBLOCK(pass)) {
2645 
2646 					if (fr_make_icmp(fin) == 0) {
2647 						IPF_BUMP(
2648 						ifs->ifs_frstats[out].fr_ret);
2649 					}
2650 					/*
2651 					 * we drop packet silently in case we
2652 					 * failed assemble fake response for it
2653 					 */
2654 					else if (*mp != NULL) {
2655 						FREE_MB_T(*mp);
2656 						m = *mp = NULL;
2657 					}
2658 
2659 					IPF_BUMP(
2660 					    ifs->ifs_frstats[out].fr_block);
2661 					RWLOCK_EXIT(&ifs->ifs_ipf_mutex);
2662 
2663 					return (0);
2664 				}
2665 #endif	/* _KERNEL && SOLARIS2 >= 10 */
2666 
2667 				(void) fr_send_icmp_err(ICMP_UNREACH, fin, dst);
2668 				IPF_BUMP(ifs->ifs_frstats[out].fr_ret);
2669 
2670 			} else if (((pass & FR_RETMASK) == FR_RETRST) &&
2671 				   !(fin->fin_flx & FI_SHORT)) {
2672 
2673 #if defined(_KERNEL) && (SOLARIS2 >= 10)
2674 				/*
2675 				 * Assume it's possible to enter insane rule:
2676 				 * 	pass return-rst in proto tcp ...
2677 				 * then we have no other option than to forward
2678 				 * packet on loopback and give up any attempt
2679 				 * to create a fake response.
2680 				 */
2681 				if (IPF_IS_LOOPBACK(qpi->qpi_flags) &&
2682 				    FR_ISBLOCK(pass)) {
2683 					if (fr_make_rst(fin) == 0) {
2684 						IPF_BUMP(
2685 						ifs->ifs_frstats[out].fr_ret);
2686 					}
2687 					else if (mp != NULL) {
2688 					/*
2689 					 * we drop packet silently in case we
2690 					 * failed assemble fake response for it
2691 					 */
2692 						FREE_MB_T(*mp);
2693 						m = *mp = NULL;
2694 					}
2695 
2696 					IPF_BUMP(
2697 					    ifs->ifs_frstats[out].fr_block);
2698 					RWLOCK_EXIT(&ifs->ifs_ipf_mutex);
2699 
2700 					return (0);
2701 				 }
2702 #endif /* _KERNEL && _SOLARIS2 >= 10 */
2703 				if (fr_send_reset(fin) == 0) {
2704 					IPF_BUMP(ifs->ifs_frstats[1].fr_ret);
2705 				}
2706 			}
2707 		} else {
2708 			if (pass & FR_RETRST)
2709 				fin->fin_error = ECONNRESET;
2710 		}
2711 	}
2712 
2713 	/*
2714 	 * If we didn't drop off the bottom of the list of rules (and thus
2715 	 * the 'current' rule fr is not NULL), then we may have some extra
2716 	 * instructions about what to do with a packet.
2717 	 * Once we're finished return to our caller, freeing the packet if
2718 	 * we are dropping it (* BSD ONLY *).
2719 	 * Reassign m from fin_m as we may have a new buffer, now.
2720 	 */
2721 filtered:
2722 	m = fin->fin_m;
2723 
2724 	if (fr != NULL) {
2725 		frdest_t *fdp;
2726 
2727 		fdp = &fr->fr_tifs[fin->fin_rev];
2728 
2729 		if (!out && (pass & FR_FASTROUTE)) {
2730 			/*
2731 			 * For fastroute rule, no destioation interface defined
2732 			 * so pass NULL as the frdest_t parameter
2733 			 */
2734 			(void) fr_fastroute(m, mp, fin, NULL);
2735 			m = *mp = NULL;
2736 		} else if ((fdp->fd_ifp != NULL) &&
2737 			   (fdp->fd_ifp != (struct ifnet *)-1)) {
2738 			/* this is for to rules: */
2739 			(void) fr_fastroute(m, mp, fin, fdp);
2740 			m = *mp = NULL;
2741 		}
2742 
2743 		/*
2744 		 * Send a duplicated packet.
2745 		 */
2746 		if (mc != NULL) {
2747 #if defined(_KERNEL) && (SOLARIS2 >= 10)
2748 			/*
2749 			 * We are going to compute chksum for copies of loopback packets
2750 			 * only. IP stack does not compute chksums at all for loopback
2751 			 * packets. We want to get it fixed in their copies, since those
2752 			 * are going to be sent to network.
2753 			 */
2754 			if (IPF_IS_LOOPBACK(qpi->qpi_flags))
2755 				fr_calc_chksum(fin, mc);
2756 #endif
2757 			(void) fr_fastroute(mc, &mc, fin, &fr->fr_dif);
2758 		}
2759 	}
2760 
2761 	if (FR_ISBLOCK(pass) && (fin->fin_flx & FI_NEWNAT))
2762 		nat_uncreate(fin);
2763 
2764 	/*
2765 	 * This late because the likes of fr_fastroute() use fin_fr.
2766 	 */
2767 	RWLOCK_EXIT(&ifs->ifs_ipf_mutex);
2768 
2769 finished:
2770 	if (!FR_ISPASS(pass)) {
2771 		IPF_BUMP(ifs->ifs_frstats[out].fr_block);
2772 		if (*mp != NULL) {
2773 			FREE_MB_T(*mp);
2774 			m = *mp = NULL;
2775 		}
2776 	} else {
2777 		IPF_BUMP(ifs->ifs_frstats[out].fr_pass);
2778 #if defined(_KERNEL) && defined(__sgi)
2779 		if ((fin->fin_hbuf != NULL) &&
2780 		    (mtod(fin->fin_m, struct ip *) != fin->fin_ip)) {
2781 			COPYBACK(m, 0, fin->fin_plen, fin->fin_hbuf);
2782 		}
2783 #endif
2784 	}
2785 
2786 	SPL_X(s);
2787 
2788 #ifdef _KERNEL
2789 # if OpenBSD >= 200311
2790 	if (FR_ISPASS(pass) && (v == 4)) {
2791 		ip = fin->fin_ip;
2792 		ip->ip_len = ntohs(ip->ip_len);
2793 		ip->ip_off = ntohs(ip->ip_off);
2794 	}
2795 # endif
2796 	return (FR_ISPASS(pass)) ? 0 : fin->fin_error;
2797 #else /* _KERNEL */
2798 	FR_VERBOSE(("fin_flx %#x pass %#x ", fin->fin_flx, pass));
2799 	if ((pass & FR_NOMATCH) != 0)
2800 		return 1;
2801 
2802 	if ((pass & FR_RETMASK) != 0)
2803 		switch (pass & FR_RETMASK)
2804 		{
2805 		case FR_RETRST :
2806 			return 3;
2807 		case FR_RETICMP :
2808 			return 4;
2809 		case FR_FAKEICMP :
2810 			return 5;
2811 		}
2812 
2813 	switch (pass & FR_CMDMASK)
2814 	{
2815 	case FR_PASS :
2816 		return 0;
2817 	case FR_BLOCK :
2818 		return -1;
2819 	case FR_AUTH :
2820 		return -2;
2821 	case FR_ACCOUNT :
2822 		return -3;
2823 	case FR_PREAUTH :
2824 		return -4;
2825 	}
2826 	return 2;
2827 #endif /* _KERNEL */
2828 }
2829 
2830 
2831 #ifdef	IPFILTER_LOG
2832 /* ------------------------------------------------------------------------ */
2833 /* Function:    fr_dolog                                                    */
2834 /* Returns:     frentry_t* - returns contents of fin_fr (no change made)    */
2835 /* Parameters:  fin(I) - pointer to packet information                      */
2836 /*              passp(IO) - pointer to current/new filter decision (unused) */
2837 /*                                                                          */
2838 /* Checks flags set to see how a packet should be logged, if it is to be    */
2839 /* logged.  Adjust statistics based on its success or not.                  */
2840 /* ------------------------------------------------------------------------ */
fr_dolog(fin,passp)2841 frentry_t *fr_dolog(fin, passp)
2842 fr_info_t *fin;
2843 u_32_t *passp;
2844 {
2845 	u_32_t pass;
2846 	int out;
2847 	ipf_stack_t *ifs = fin->fin_ifs;
2848 
2849 	out = fin->fin_out;
2850 	pass = *passp;
2851 
2852 	if ((ifs->ifs_fr_flags & FF_LOGNOMATCH) && (pass & FR_NOMATCH)) {
2853 		pass |= FF_LOGNOMATCH;
2854 		IPF_BUMP(ifs->ifs_frstats[out].fr_npkl);
2855 		goto logit;
2856 	} else if (((pass & FR_LOGMASK) == FR_LOGP) ||
2857 	    (FR_ISPASS(pass) && (ifs->ifs_fr_flags & FF_LOGPASS))) {
2858 		if ((pass & FR_LOGMASK) != FR_LOGP)
2859 			pass |= FF_LOGPASS;
2860 		IPF_BUMP(ifs->ifs_frstats[out].fr_ppkl);
2861 		goto logit;
2862 	} else if (((pass & FR_LOGMASK) == FR_LOGB) ||
2863 		   (FR_ISBLOCK(pass) && (ifs->ifs_fr_flags & FF_LOGBLOCK))) {
2864 		if ((pass & FR_LOGMASK) != FR_LOGB)
2865 			pass |= FF_LOGBLOCK;
2866 		IPF_BUMP(ifs->ifs_frstats[out].fr_bpkl);
2867 logit:
2868 		if (ipflog(fin, pass) == -1) {
2869 			IPF_BUMP(ifs->ifs_frstats[out].fr_skip);
2870 
2871 			/*
2872 			 * If the "or-block" option has been used then
2873 			 * block the packet if we failed to log it.
2874 			 */
2875 			if ((pass & FR_LOGORBLOCK) &&
2876 			    FR_ISPASS(pass)) {
2877 				pass &= ~FR_CMDMASK;
2878 				pass |= FR_BLOCK;
2879 			}
2880 		}
2881 		*passp = pass;
2882 	}
2883 
2884 	return fin->fin_fr;
2885 }
2886 #endif /* IPFILTER_LOG */
2887 
2888 
2889 /* ------------------------------------------------------------------------ */
2890 /* Function:    ipf_cksum                                                   */
2891 /* Returns:     u_short - IP header checksum                                */
2892 /* Parameters:  addr(I) - pointer to start of buffer to checksum            */
2893 /*              len(I)  - length of buffer in bytes                         */
2894 /*                                                                          */
2895 /* Calculate the two's complement 16 bit checksum of the buffer passed.     */
2896 /*                                                                          */
2897 /* N.B.: addr should be 16bit aligned.                                      */
2898 /* ------------------------------------------------------------------------ */
ipf_cksum(addr,len)2899 u_short ipf_cksum(addr, len)
2900 u_short *addr;
2901 int len;
2902 {
2903 	u_32_t sum = 0;
2904 
2905 	for (sum = 0; len > 1; len -= 2)
2906 		sum += *addr++;
2907 
2908 	/* mop up an odd byte, if necessary */
2909 	if (len == 1)
2910 		sum += *(u_char *)addr;
2911 
2912 	/*
2913 	 * add back carry outs from top 16 bits to low 16 bits
2914 	 */
2915 	sum = (sum >> 16) + (sum & 0xffff);	/* add hi 16 to low 16 */
2916 	sum += (sum >> 16);			/* add carry */
2917 	return (u_short)(~sum);
2918 }
2919 
2920 
2921 /* ------------------------------------------------------------------------ */
2922 /* Function:    fr_cksum                                                    */
2923 /* Returns:     u_short - layer 4 checksum                                  */
2924 /* Parameters:  m(I  )     - pointer to buffer holding packet               */
2925 /*              ip(I)      - pointer to IP header                           */
2926 /*              l4proto(I) - protocol to caclulate checksum for             */
2927 /*              l4hdr(I)   - pointer to layer 4 header                      */
2928 /*                                                                          */
2929 /* Calculates the TCP checksum for the packet held in "m", using the data   */
2930 /* in the IP header "ip" to seed it.                                        */
2931 /*                                                                          */
2932 /* NB: This function assumes we've pullup'd enough for all of the IP header */
2933 /* and the TCP header.  We also assume that data blocks aren't allocated in */
2934 /* odd sizes.                                                               */
2935 /*                                                                          */
2936 /* Expects ip_len to be in host byte order when called.                     */
2937 /* ------------------------------------------------------------------------ */
fr_cksum(m,ip,l4proto,l4hdr)2938 u_short fr_cksum(m, ip, l4proto, l4hdr)
2939 mb_t *m;
2940 ip_t *ip;
2941 int l4proto;
2942 void *l4hdr;
2943 {
2944 	u_short *sp, slen, sumsave, l4hlen, *csump;
2945 	u_int sum, sum2;
2946 	int hlen;
2947 #ifdef	USE_INET6
2948 	ip6_t *ip6;
2949 #endif
2950 
2951 	csump = NULL;
2952 	sumsave = 0;
2953 	l4hlen = 0;
2954 	sp = NULL;
2955 	slen = 0;
2956 	hlen = 0;
2957 	sum = 0;
2958 
2959 	/*
2960 	 * Add up IP Header portion
2961 	 */
2962 #ifdef	USE_INET6
2963 	if (IP_V(ip) == 4) {
2964 #endif
2965 		hlen = IP_HL(ip) << 2;
2966 		slen = ip->ip_len - hlen;
2967 		sum = htons((u_short)l4proto);
2968 		sum += htons(slen);
2969 		sp = (u_short *)&ip->ip_src;
2970 		sum += *sp++;	/* ip_src */
2971 		sum += *sp++;
2972 		sum += *sp++;	/* ip_dst */
2973 		sum += *sp++;
2974 #ifdef	USE_INET6
2975 	} else if (IP_V(ip) == 6) {
2976 		ip6 = (ip6_t *)ip;
2977 		hlen = sizeof(*ip6);
2978 		slen = ntohs(ip6->ip6_plen);
2979 		sum = htons((u_short)l4proto);
2980 		sum += htons(slen);
2981 		sp = (u_short *)&ip6->ip6_src;
2982 		sum += *sp++;	/* ip6_src */
2983 		sum += *sp++;
2984 		sum += *sp++;
2985 		sum += *sp++;
2986 		sum += *sp++;
2987 		sum += *sp++;
2988 		sum += *sp++;
2989 		sum += *sp++;
2990 		sum += *sp++;	/* ip6_dst */
2991 		sum += *sp++;
2992 		sum += *sp++;
2993 		sum += *sp++;
2994 		sum += *sp++;
2995 		sum += *sp++;
2996 		sum += *sp++;
2997 		sum += *sp++;
2998 	}
2999 #endif
3000 
3001 	switch (l4proto)
3002 	{
3003 	case IPPROTO_UDP :
3004 		csump = &((udphdr_t *)l4hdr)->uh_sum;
3005 		l4hlen = sizeof(udphdr_t);
3006 		break;
3007 
3008 	case IPPROTO_TCP :
3009 		csump = &((tcphdr_t *)l4hdr)->th_sum;
3010 		l4hlen = sizeof(tcphdr_t);
3011 		break;
3012 	case IPPROTO_ICMP :
3013 		csump = &((icmphdr_t *)l4hdr)->icmp_cksum;
3014 		l4hlen = 4;
3015 		sum = 0;
3016 		break;
3017 	default :
3018 		break;
3019 	}
3020 
3021 	if (csump != NULL) {
3022 		sumsave = *csump;
3023 		*csump = 0;
3024 	}
3025 
3026 	l4hlen = l4hlen;	/* LINT */
3027 
3028 #ifdef	_KERNEL
3029 # ifdef MENTAT
3030 	{
3031 	void *rp = m->b_rptr;
3032 
3033 	if ((unsigned char *)ip > m->b_rptr && (unsigned char *)ip < m->b_wptr)
3034 		m->b_rptr = (u_char *)ip;
3035 	sum2 = ip_cksum(m, hlen, sum);	/* hlen == offset */
3036 	m->b_rptr = rp;
3037 	sum2 = (sum2 & 0xffff) + (sum2 >> 16);
3038 	sum2 = ~sum2 & 0xffff;
3039 	}
3040 # else /* MENTAT */
3041 #  if defined(BSD) || defined(sun)
3042 #   if BSD >= 199103
3043 	m->m_data += hlen;
3044 #   else
3045 	m->m_off += hlen;
3046 #   endif
3047 	m->m_len -= hlen;
3048 	sum2 = in_cksum(m, slen);
3049 	m->m_len += hlen;
3050 #   if BSD >= 199103
3051 	m->m_data -= hlen;
3052 #   else
3053 	m->m_off -= hlen;
3054 #   endif
3055 	/*
3056 	 * Both sum and sum2 are partial sums, so combine them together.
3057 	 */
3058 	sum += ~sum2 & 0xffff;
3059 	while (sum > 0xffff)
3060 		sum = (sum & 0xffff) + (sum >> 16);
3061 	sum2 = ~sum & 0xffff;
3062 #  else /* defined(BSD) || defined(sun) */
3063 {
3064 	union {
3065 		u_char	c[2];
3066 		u_short	s;
3067 	} bytes;
3068 	u_short len = ip->ip_len;
3069 #   if defined(__sgi)
3070 	int add;
3071 #   endif
3072 
3073 	/*
3074 	 * Add up IP Header portion
3075 	 */
3076 	if (sp != (u_short *)l4hdr)
3077 		sp = (u_short *)l4hdr;
3078 
3079 	switch (l4proto)
3080 	{
3081 	case IPPROTO_UDP :
3082 		sum += *sp++;	/* sport */
3083 		sum += *sp++;	/* dport */
3084 		sum += *sp++;	/* udp length */
3085 		sum += *sp++;	/* checksum */
3086 		break;
3087 
3088 	case IPPROTO_TCP :
3089 		sum += *sp++;	/* sport */
3090 		sum += *sp++;	/* dport */
3091 		sum += *sp++;	/* seq */
3092 		sum += *sp++;
3093 		sum += *sp++;	/* ack */
3094 		sum += *sp++;
3095 		sum += *sp++;	/* off */
3096 		sum += *sp++;	/* win */
3097 		sum += *sp++;	/* checksum */
3098 		sum += *sp++;	/* urp */
3099 		break;
3100 	case IPPROTO_ICMP :
3101 		sum = *sp++;	/* type/code */
3102 		sum += *sp++;	/* checksum */
3103 		break;
3104 	}
3105 
3106 #   ifdef	__sgi
3107 	/*
3108 	 * In case we had to copy the IP & TCP header out of mbufs,
3109 	 * skip over the mbuf bits which are the header
3110 	 */
3111 	if ((caddr_t)ip != mtod(m, caddr_t)) {
3112 		hlen = (caddr_t)sp - (caddr_t)ip;
3113 		while (hlen) {
3114 			add = MIN(hlen, m->m_len);
3115 			sp = (u_short *)(mtod(m, caddr_t) + add);
3116 			hlen -= add;
3117 			if (add == m->m_len) {
3118 				m = m->m_next;
3119 				if (!hlen) {
3120 					if (!m)
3121 						break;
3122 					sp = mtod(m, u_short *);
3123 				}
3124 				PANIC((!m),("fr_cksum(1): not enough data"));
3125 			}
3126 		}
3127 	}
3128 #   endif
3129 
3130 	len -= (l4hlen + hlen);
3131 	if (len <= 0)
3132 		goto nodata;
3133 
3134 	while (len > 1) {
3135 		if (((caddr_t)sp - mtod(m, caddr_t)) >= m->m_len) {
3136 			m = m->m_next;
3137 			PANIC((!m),("fr_cksum(2): not enough data"));
3138 			sp = mtod(m, u_short *);
3139 		}
3140 		if (((caddr_t)(sp + 1) - mtod(m, caddr_t)) > m->m_len) {
3141 			bytes.c[0] = *(u_char *)sp;
3142 			m = m->m_next;
3143 			PANIC((!m),("fr_cksum(3): not enough data"));
3144 			sp = mtod(m, u_short *);
3145 			bytes.c[1] = *(u_char *)sp;
3146 			sum += bytes.s;
3147 			sp = (u_short *)((u_char *)sp + 1);
3148 		}
3149 		if ((u_long)sp & 1) {
3150 			bcopy((char *)sp++, (char *)&bytes.s, sizeof(bytes.s));
3151 			sum += bytes.s;
3152 		} else
3153 			sum += *sp++;
3154 		len -= 2;
3155 	}
3156 
3157 	if (len != 0)
3158 		sum += ntohs(*(u_char *)sp << 8);
3159 nodata:
3160 	while (sum > 0xffff)
3161 		sum = (sum & 0xffff) + (sum >> 16);
3162 	sum2 = (u_short)(~sum & 0xffff);
3163 }
3164 #  endif /*  defined(BSD) || defined(sun) */
3165 # endif /* MENTAT */
3166 #else /* _KERNEL */
3167 	for (; slen > 1; slen -= 2)
3168 	        sum += *sp++;
3169 	if (slen)
3170 		sum += ntohs(*(u_char *)sp << 8);
3171 	while (sum > 0xffff)
3172 		sum = (sum & 0xffff) + (sum >> 16);
3173 	sum2 = (u_short)(~sum & 0xffff);
3174 #endif /* _KERNEL */
3175 	if (csump != NULL)
3176 		*csump = sumsave;
3177 	return sum2;
3178 }
3179 
3180 
3181 #if defined(_KERNEL) && ( ((BSD < 199103) && !defined(MENTAT)) || \
3182     defined(__sgi) ) && !defined(linux) && !defined(_AIX51)
3183 /*
3184  * Copyright (c) 1982, 1986, 1988, 1991, 1993
3185  *	The Regents of the University of California.  All rights reserved.
3186  *
3187  * Redistribution and use in source and binary forms, with or without
3188  * modification, are permitted provided that the following conditions
3189  * are met:
3190  * 1. Redistributions of source code must retain the above copyright
3191  *    notice, this list of conditions and the following disclaimer.
3192  * 2. Redistributions in binary form must reproduce the above copyright
3193  *    notice, this list of conditions and the following disclaimer in the
3194  *    documentation and/or other materials provided with the distribution.
3195  * 3. Neither the name of the University nor the names of its contributors
3196  *    may be used to endorse or promote products derived from this software
3197  *    without specific prior written permission.
3198  *
3199  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
3200  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
3201  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
3202  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
3203  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
3204  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
3205  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
3206  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
3207  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
3208  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
3209  * SUCH DAMAGE.
3210  *
3211  *	@(#)uipc_mbuf.c	8.2 (Berkeley) 1/4/94
3212  * $Id: fil.c,v 2.243.2.64 2005/08/13 05:19:59 darrenr Exp $
3213  */
3214 /*
3215  * Copy data from an mbuf chain starting "off" bytes from the beginning,
3216  * continuing for "len" bytes, into the indicated buffer.
3217  */
3218 void
m_copydata(m,off,len,cp)3219 m_copydata(m, off, len, cp)
3220 	mb_t *m;
3221 	int off;
3222 	int len;
3223 	caddr_t cp;
3224 {
3225 	unsigned count;
3226 
3227 	if (off < 0 || len < 0)
3228 		panic("m_copydata");
3229 	while (off > 0) {
3230 		if (m == 0)
3231 			panic("m_copydata");
3232 		if (off < m->m_len)
3233 			break;
3234 		off -= m->m_len;
3235 		m = m->m_next;
3236 	}
3237 	while (len > 0) {
3238 		if (m == 0)
3239 			panic("m_copydata");
3240 		count = MIN(m->m_len - off, len);
3241 		bcopy(mtod(m, caddr_t) + off, cp, count);
3242 		len -= count;
3243 		cp += count;
3244 		off = 0;
3245 		m = m->m_next;
3246 	}
3247 }
3248 
3249 
3250 /*
3251  * Copy data from a buffer back into the indicated mbuf chain,
3252  * starting "off" bytes from the beginning, extending the mbuf
3253  * chain if necessary.
3254  */
3255 void
m_copyback(m0,off,len,cp)3256 m_copyback(m0, off, len, cp)
3257 	struct	mbuf *m0;
3258 	int off;
3259 	int len;
3260 	caddr_t cp;
3261 {
3262 	int mlen;
3263 	struct mbuf *m = m0, *n;
3264 	int totlen = 0;
3265 
3266 	if (m0 == 0)
3267 		return;
3268 	while (off > (mlen = m->m_len)) {
3269 		off -= mlen;
3270 		totlen += mlen;
3271 		if (m->m_next == 0) {
3272 			n = m_getclr(M_DONTWAIT, m->m_type);
3273 			if (n == 0)
3274 				goto out;
3275 			n->m_len = min(MLEN, len + off);
3276 			m->m_next = n;
3277 		}
3278 		m = m->m_next;
3279 	}
3280 	while (len > 0) {
3281 		mlen = min(m->m_len - off, len);
3282 		bcopy(cp, off + mtod(m, caddr_t), (unsigned)mlen);
3283 		cp += mlen;
3284 		len -= mlen;
3285 		mlen += off;
3286 		off = 0;
3287 		totlen += mlen;
3288 		if (len == 0)
3289 			break;
3290 		if (m->m_next == 0) {
3291 			n = m_get(M_DONTWAIT, m->m_type);
3292 			if (n == 0)
3293 				break;
3294 			n->m_len = min(MLEN, len);
3295 			m->m_next = n;
3296 		}
3297 		m = m->m_next;
3298 	}
3299 out:
3300 #if 0
3301 	if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen))
3302 		m->m_pkthdr.len = totlen;
3303 #endif
3304 	return;
3305 }
3306 #endif /* (_KERNEL) && ( ((BSD < 199103) && !MENTAT) || __sgi) */
3307 
3308 
3309 /* ------------------------------------------------------------------------ */
3310 /* Function:    fr_findgroup                                                */
3311 /* Returns:     frgroup_t * - NULL = group not found, else pointer to group */
3312 /* Parameters:  group(I) - group name to search for                         */
3313 /*              unit(I)  - device to which this group belongs               */
3314 /*              set(I)   - which set of rules (inactive/inactive) this is   */
3315 /*              fgpp(O)  - pointer to place to store pointer to the pointer */
3316 /*                         to where to add the next (last) group or where   */
3317 /*                         to delete group from.                            */
3318 /*                                                                          */
3319 /* Search amongst the defined groups for a particular group number.         */
3320 /* ------------------------------------------------------------------------ */
fr_findgroup(group,unit,set,fgpp,ifs)3321 frgroup_t *fr_findgroup(group, unit, set, fgpp, ifs)
3322 char *group;
3323 minor_t unit;
3324 int set;
3325 frgroup_t ***fgpp;
3326 ipf_stack_t *ifs;
3327 {
3328 	frgroup_t *fg, **fgp;
3329 
3330 	/*
3331 	 * Which list of groups to search in is dependent on which list of
3332 	 * rules are being operated on.
3333 	 */
3334 	fgp = &ifs->ifs_ipfgroups[unit][set];
3335 
3336 	while ((fg = *fgp) != NULL) {
3337 		if (strncmp(group, fg->fg_name, FR_GROUPLEN) == 0)
3338 			break;
3339 		else
3340 			fgp = &fg->fg_next;
3341 	}
3342 	if (fgpp != NULL)
3343 		*fgpp = fgp;
3344 	return fg;
3345 }
3346 
3347 
3348 /* ------------------------------------------------------------------------ */
3349 /* Function:    fr_addgroup                                                 */
3350 /* Returns:     frgroup_t * - NULL == did not create group,                 */
3351 /*                            != NULL == pointer to the group               */
3352 /* Parameters:  num(I)   - group number to add                              */
3353 /*              head(I)  - rule pointer that is using this as the head      */
3354 /*              flags(I) - rule flags which describe the type of rule it is */
3355 /*              unit(I)  - device to which this group will belong to        */
3356 /*              set(I)   - which set of rules (inactive/inactive) this is   */
3357 /* Write Locks: ipf_mutex                                                   */
3358 /*                                                                          */
3359 /* Add a new group head, or if it already exists, increase the reference    */
3360 /* count to it.                                                             */
3361 /* ------------------------------------------------------------------------ */
fr_addgroup(group,head,flags,unit,set,ifs)3362 frgroup_t *fr_addgroup(group, head, flags, unit, set, ifs)
3363 char *group;
3364 void *head;
3365 u_32_t flags;
3366 minor_t unit;
3367 int set;
3368 ipf_stack_t *ifs;
3369 {
3370 	frgroup_t *fg, **fgp;
3371 	u_32_t gflags;
3372 
3373 	if (group == NULL)
3374 		return NULL;
3375 
3376 	if (unit == IPL_LOGIPF && *group == '\0')
3377 		return NULL;
3378 
3379 	fgp = NULL;
3380 	gflags = flags & FR_INOUT;
3381 
3382 	fg = fr_findgroup(group, unit, set, &fgp, ifs);
3383 	if (fg != NULL) {
3384 		if (fg->fg_flags == 0)
3385 			fg->fg_flags = gflags;
3386 		else if (gflags != fg->fg_flags)
3387 			return NULL;
3388 		fg->fg_ref++;
3389 		return fg;
3390 	}
3391 	KMALLOC(fg, frgroup_t *);
3392 	if (fg != NULL) {
3393 		fg->fg_head = head;
3394 		fg->fg_start = NULL;
3395 		fg->fg_next = *fgp;
3396 		bcopy(group, fg->fg_name, FR_GROUPLEN);
3397 		fg->fg_flags = gflags;
3398 		fg->fg_ref = 1;
3399 		*fgp = fg;
3400 	}
3401 	return fg;
3402 }
3403 
3404 
3405 /* ------------------------------------------------------------------------ */
3406 /* Function:    fr_delgroup                                                 */
3407 /* Returns:     Nil                                                         */
3408 /* Parameters:  group(I) - group name to delete                             */
3409 /*              unit(I)  - device to which this group belongs               */
3410 /*              set(I)   - which set of rules (inactive/inactive) this is   */
3411 /* Write Locks: ipf_mutex                                                   */
3412 /*                                                                          */
3413 /* Attempt to delete a group head.                                          */
3414 /* Only do this when its reference count reaches 0.                         */
3415 /* ------------------------------------------------------------------------ */
fr_delgroup(group,unit,set,ifs)3416 void fr_delgroup(group, unit, set, ifs)
3417 char *group;
3418 minor_t unit;
3419 int set;
3420 ipf_stack_t *ifs;
3421 {
3422 	frgroup_t *fg, **fgp;
3423 
3424 	fg = fr_findgroup(group, unit, set, &fgp, ifs);
3425 	if (fg == NULL)
3426 		return;
3427 
3428 	fg->fg_ref--;
3429 	if (fg->fg_ref == 0) {
3430 		*fgp = fg->fg_next;
3431 		KFREE(fg);
3432 	}
3433 }
3434 
3435 
3436 /* ------------------------------------------------------------------------ */
3437 /* Function:    fr_getrulen                                                 */
3438 /* Returns:     frentry_t * - NULL == not found, else pointer to rule n     */
3439 /* Parameters:  unit(I)  - device for which to count the rule's number      */
3440 /*              flags(I) - which set of rules to find the rule in           */
3441 /*              group(I) - group name                                       */
3442 /*              n(I)     - rule number to find                              */
3443 /*                                                                          */
3444 /* Find rule # n in group # g and return a pointer to it.  Return NULl if   */
3445 /* group # g doesn't exist or there are less than n rules in the group.     */
3446 /* ------------------------------------------------------------------------ */
fr_getrulen(unit,group,n,ifs)3447 frentry_t *fr_getrulen(unit, group, n, ifs)
3448 int unit;
3449 char *group;
3450 u_32_t n;
3451 ipf_stack_t *ifs;
3452 {
3453 	frentry_t *fr;
3454 	frgroup_t *fg;
3455 
3456 	fg = fr_findgroup(group, unit, ifs->ifs_fr_active, NULL, ifs);
3457 	if (fg == NULL)
3458 		return NULL;
3459 	for (fr = fg->fg_head; fr && n; fr = fr->fr_next, n--)
3460 		;
3461 	if (n != 0)
3462 		return NULL;
3463 	return fr;
3464 }
3465 
3466 
3467 /* ------------------------------------------------------------------------ */
3468 /* Function:    fr_rulen                                                    */
3469 /* Returns:     int - >= 0 - rule number, -1 == search failed               */
3470 /* Parameters:  unit(I) - device for which to count the rule's number       */
3471 /*              fr(I)   - pointer to rule to match                          */
3472 /*                                                                          */
3473 /* Return the number for a rule on a specific filtering device.             */
3474 /* ------------------------------------------------------------------------ */
fr_rulen(unit,fr,ifs)3475 int fr_rulen(unit, fr, ifs)
3476 int unit;
3477 frentry_t *fr;
3478 ipf_stack_t *ifs;
3479 {
3480 	frentry_t *fh;
3481 	frgroup_t *fg;
3482 	u_32_t n = 0;
3483 
3484 	if (fr == NULL)
3485 		return -1;
3486 	fg = fr_findgroup(fr->fr_group, unit, ifs->ifs_fr_active, NULL, ifs);
3487 	if (fg == NULL)
3488 		return -1;
3489 	for (fh = fg->fg_head; fh; n++, fh = fh->fr_next)
3490 		if (fh == fr)
3491 			break;
3492 	if (fh == NULL)
3493 		return -1;
3494 	return n;
3495 }
3496 
3497 
3498 /* ------------------------------------------------------------------------ */
3499 /* Function:    frflushlist                                                 */
3500 /* Returns:     int - >= 0 - number of flushed rules                        */
3501 /* Parameters:  set(I)   - which set of rules (inactive/inactive) this is   */
3502 /*              unit(I)  - device for which to flush rules                  */
3503 /*              flags(I) - which set of rules to flush                      */
3504 /*              nfreedp(O) - pointer to int where flush count is stored     */
3505 /*              listp(I)   - pointer to list to flush pointer               */
3506 /* Write Locks: ipf_mutex                                                   */
3507 /*                                                                          */
3508 /* Recursively flush rules from the list, descending groups as they are     */
3509 /* encountered.  if a rule is the head of a group and it has lost all its   */
3510 /* group members, then also delete the group reference.  nfreedp is needed  */
3511 /* to store the accumulating count of rules removed, whereas the returned   */
3512 /* value is just the number removed from the current list.  The latter is   */
3513 /* needed to correctly adjust reference counts on rules that define groups. */
3514 /*                                                                          */
3515 /* NOTE: Rules not loaded from user space cannot be flushed.                */
3516 /* ------------------------------------------------------------------------ */
frflushlist(set,unit,nfreedp,listp,ifs)3517 static int frflushlist(set, unit, nfreedp, listp, ifs)
3518 int set;
3519 minor_t unit;
3520 int *nfreedp;
3521 frentry_t **listp;
3522 ipf_stack_t *ifs;
3523 {
3524 	int freed = 0;
3525 	frentry_t *fp;
3526 
3527 	while ((fp = *listp) != NULL) {
3528 		if ((fp->fr_type & FR_T_BUILTIN) ||
3529 		    !(fp->fr_flags & FR_COPIED)) {
3530 			listp = &fp->fr_next;
3531 			continue;
3532 		}
3533 		*listp = fp->fr_next;
3534 		if (fp->fr_grp != NULL) {
3535 			(void) frflushlist(set, unit, nfreedp, fp->fr_grp, ifs);
3536 		}
3537 
3538 		if (fp->fr_grhead != NULL) {
3539 			fr_delgroup(fp->fr_grhead, unit, set, ifs);
3540 			*fp->fr_grhead = '\0';
3541 		}
3542 
3543 		ASSERT(fp->fr_ref > 0);
3544 		fp->fr_next = NULL;
3545 		if (fr_derefrule(&fp, ifs) == 0)
3546 			freed++;
3547 	}
3548 	*nfreedp += freed;
3549 	return freed;
3550 }
3551 
3552 
3553 /* ------------------------------------------------------------------------ */
3554 /* Function:    frflush                                                     */
3555 /* Returns:     int - >= 0 - number of flushed rules                        */
3556 /* Parameters:  unit(I)  - device for which to flush rules                  */
3557 /*              flags(I) - which set of rules to flush                      */
3558 /*                                                                          */
3559 /* Calls flushlist() for all filter rules (accounting, firewall - both IPv4 */
3560 /* and IPv6) as defined by the value of flags.                              */
3561 /* ------------------------------------------------------------------------ */
frflush(unit,proto,flags,ifs)3562 int frflush(unit, proto, flags, ifs)
3563 minor_t unit;
3564 int proto, flags;
3565 ipf_stack_t *ifs;
3566 {
3567 	int flushed = 0, set;
3568 
3569 	WRITE_ENTER(&ifs->ifs_ipf_mutex);
3570 	bzero((char *)ifs->ifs_frcache, sizeof (ifs->ifs_frcache));
3571 
3572 	set = ifs->ifs_fr_active;
3573 	if ((flags & FR_INACTIVE) == FR_INACTIVE)
3574 		set = 1 - set;
3575 
3576 	if (flags & FR_OUTQUE) {
3577 		if (proto == 0 || proto == 6) {
3578 			(void) frflushlist(set, unit,
3579 			    &flushed, &ifs->ifs_ipfilter6[1][set], ifs);
3580 			(void) frflushlist(set, unit,
3581 			    &flushed, &ifs->ifs_ipacct6[1][set], ifs);
3582 		}
3583 		if (proto == 0 || proto == 4) {
3584 			(void) frflushlist(set, unit,
3585 			    &flushed, &ifs->ifs_ipfilter[1][set], ifs);
3586 			(void) frflushlist(set, unit,
3587 			    &flushed, &ifs->ifs_ipacct[1][set], ifs);
3588 		}
3589 	}
3590 	if (flags & FR_INQUE) {
3591 		if (proto == 0 || proto == 6) {
3592 			(void) frflushlist(set, unit,
3593 			    &flushed, &ifs->ifs_ipfilter6[0][set], ifs);
3594 			(void) frflushlist(set, unit,
3595 			    &flushed, &ifs->ifs_ipacct6[0][set], ifs);
3596 		}
3597 		if (proto == 0 || proto == 4) {
3598 			(void) frflushlist(set, unit,
3599 			    &flushed, &ifs->ifs_ipfilter[0][set], ifs);
3600 			(void) frflushlist(set, unit,
3601 			    &flushed, &ifs->ifs_ipacct[0][set], ifs);
3602 		}
3603 	}
3604 	RWLOCK_EXIT(&ifs->ifs_ipf_mutex);
3605 
3606 	if (unit == IPL_LOGIPF) {
3607 		int tmp;
3608 
3609 		tmp = frflush(IPL_LOGCOUNT, proto, flags, ifs);
3610 		if (tmp >= 0)
3611 			flushed += tmp;
3612 	}
3613 	return flushed;
3614 }
3615 
3616 
3617 /* ------------------------------------------------------------------------ */
3618 /* Function:    memstr                                                      */
3619 /* Returns:     char *  - NULL if failed, != NULL pointer to matching bytes */
3620 /* Parameters:  src(I)  - pointer to byte sequence to match                 */
3621 /*              dst(I)  - pointer to byte sequence to search                */
3622 /*              slen(I) - match length                                      */
3623 /*              dlen(I) - length available to search in                     */
3624 /*                                                                          */
3625 /* Search dst for a sequence of bytes matching those at src and extend for  */
3626 /* slen bytes.                                                              */
3627 /* ------------------------------------------------------------------------ */
memstr(src,dst,slen,dlen)3628 char *memstr(src, dst, slen, dlen)
3629 char *src, *dst;
3630 int slen, dlen;
3631 {
3632 	char *s = NULL;
3633 
3634 	while (dlen >= slen) {
3635 		if (bcmp(src, dst, slen) == 0) {
3636 			s = dst;
3637 			break;
3638 		}
3639 		dst++;
3640 		dlen--;
3641 	}
3642 	return s;
3643 }
3644 /* ------------------------------------------------------------------------ */
3645 /* Function:    fr_fixskip                                                  */
3646 /* Returns:     Nil                                                         */
3647 /* Parameters:  listp(IO)    - pointer to start of list with skip rule      */
3648 /*              rp(I)        - rule added/removed with skip in it.          */
3649 /*              addremove(I) - adjustment (-1/+1) to make to skip count,    */
3650 /*                             depending on whether a rule was just added   */
3651 /*                             or removed.                                  */
3652 /*                                                                          */
3653 /* Adjust all the rules in a list which would have skip'd past the position */
3654 /* where we are inserting to skip to the right place given the change.      */
3655 /* ------------------------------------------------------------------------ */
fr_fixskip(listp,rp,addremove)3656 void fr_fixskip(listp, rp, addremove)
3657 frentry_t **listp, *rp;
3658 int addremove;
3659 {
3660 	int rules, rn;
3661 	frentry_t *fp;
3662 
3663 	rules = 0;
3664 	for (fp = *listp; (fp != NULL) && (fp != rp); fp = fp->fr_next)
3665 		rules++;
3666 
3667 	if (!fp)
3668 		return;
3669 
3670 	for (rn = 0,