1 
2 /*
3  * Copyright (C) 2012 by Darren Reed.
4  *
5  * See the IPFILTER.LICENCE file for details on licencing.
6  */
7 #if !defined(lint)
8 static const char sccsid[] = "@(#)ip_fil.c	2.41 6/5/96 (C) 1993-2000 Darren Reed";
9 static const char rcsid[] = "@(#)$Id$";
10 #endif
11 
12 #if defined(KERNEL) || defined(_KERNEL)
13 # undef KERNEL
14 # undef _KERNEL
15 # define	KERNEL	1
16 # define	_KERNEL	1
17 #endif
18 #if defined(__FreeBSD__) && \
19     !defined(KLD_MODULE) && !defined(IPFILTER_LKM)
20 # include "opt_inet6.h"
21 #endif
22 #include <sys/param.h>
23 #include <sys/eventhandler.h>
24 #include <sys/conf.h>
25 #include <sys/errno.h>
26 #include <sys/types.h>
27 #include <sys/file.h>
28 #include <sys/fcntl.h>
29 #include <sys/filio.h>
30 #include <sys/time.h>
31 #include <sys/systm.h>
32 #include <sys/dirent.h>
33 #if defined(__FreeBSD__)
34 # include <sys/jail.h>
35 #endif
36 #include <sys/malloc.h>
37 #include <sys/mbuf.h>
38 #include <sys/sockopt.h>
39 #include <sys/socket.h>
40 #include <sys/selinfo.h>
41 #include <net/if.h>
42 #include <net/if_var.h>
43 #include <net/netisr.h>
44 #include <net/route.h>
45 #include <net/route/nhop.h>
46 #include <netinet/in.h>
47 #include <netinet/in_fib.h>
48 #include <netinet/in_pcb.h>
49 #include <netinet/in_var.h>
50 #include <netinet/in_systm.h>
51 #include <netinet/ip.h>
52 #include <netinet/ip_var.h>
53 #include <netinet/tcp.h>
54 #include <netinet/tcp_var.h>
55 #include <net/vnet.h>
56 #include <netinet/udp.h>
57 #include <netinet/tcpip.h>
58 #include <netinet/ip_icmp.h>
59 #include "netinet/ip_compat.h"
60 #ifdef USE_INET6
61 # include <netinet/icmp6.h>
62 #endif
63 #include "netinet/ip_fil.h"
64 #include "netinet/ip_nat.h"
65 #include "netinet/ip_frag.h"
66 #include "netinet/ip_state.h"
67 #include "netinet/ip_proxy.h"
68 #include "netinet/ip_auth.h"
69 #include "netinet/ip_sync.h"
70 #include "netinet/ip_lookup.h"
71 #include "netinet/ip_dstlist.h"
72 #ifdef	IPFILTER_SCAN
73 # include "netinet/ip_scan.h"
74 #endif
75 #include "netinet/ip_pool.h"
76 #include <sys/malloc.h>
77 #include <sys/kernel.h>
78 #ifdef CSUM_DATA_VALID
79 # include <machine/in_cksum.h>
80 #endif
81 extern	int	ip_optcopy(struct ip *, struct ip *);
82 
83 #ifdef IPFILTER_M_IPFILTER
84 MALLOC_DEFINE(M_IPFILTER, "ipfilter", "IP Filter packet filter data structures");
85 #endif
86 
87 
88 static	int	ipf_send_ip(fr_info_t *, mb_t *);
89 static void	ipf_timer_func(void *arg);
90 
91 VNET_DEFINE(ipf_main_softc_t, ipfmain) = {
92 	.ipf_running		= -2,
93 };
94 #define	V_ipfmain		VNET(ipfmain)
95 
96 #include <sys/conf.h>
97 #include <net/pfil.h>
98 
99 VNET_DEFINE_STATIC(eventhandler_tag, ipf_arrivetag);
100 VNET_DEFINE_STATIC(eventhandler_tag, ipf_departtag);
101 #define	V_ipf_arrivetag		VNET(ipf_arrivetag)
102 #define	V_ipf_departtag		VNET(ipf_departtag)
103 #if 0
104 /*
105  * Disable the "cloner" event handler;  we are getting interface
106  * events before the firewall is fully initiallized and also no vnet
107  * information thus leading to uninitialised memory accesses.
108  * In addition it is unclear why we need it in first place.
109  * If it turns out to be needed, well need a dedicated event handler
110  * for it to deal with the ifc and the correct vnet.
111  */
112 VNET_DEFINE_STATIC(eventhandler_tag, ipf_clonetag);
113 #define	V_ipf_clonetag		VNET(ipf_clonetag)
114 #endif
115 
116 static void ipf_ifevent(void *arg, struct ifnet *ifp);
117 
118 static void ipf_ifevent(void *arg, struct ifnet *ifp)
119 {
120 
121 	CURVNET_SET(ifp->if_vnet);
122 	if (V_ipfmain.ipf_running > 0)
123 		ipf_sync(&V_ipfmain, NULL);
124 	CURVNET_RESTORE();
125 }
126 
127 
128 
129 static pfil_return_t
130 ipf_check_wrapper(struct mbuf **mp, struct ifnet *ifp, int flags,
131     void *ruleset __unused, struct inpcb *inp)
132 {
133 	struct ip *ip = mtod(*mp, struct ip *);
134 	pfil_return_t rv;
135 
136 	CURVNET_SET(ifp->if_vnet);
137 	rv = ipf_check(&V_ipfmain, ip, ip->ip_hl << 2, ifp,
138 	    !!(flags & PFIL_OUT), mp);
139 	CURVNET_RESTORE();
140 	return (rv == 0 ? PFIL_PASS : PFIL_DROPPED);
141 }
142 
143 #ifdef USE_INET6
144 static pfil_return_t
145 ipf_check_wrapper6(struct mbuf **mp, struct ifnet *ifp, int flags,
146     void *ruleset __unused, struct inpcb *inp)
147 {
148 	pfil_return_t rv;
149 
150 	CURVNET_SET(ifp->if_vnet);
151 	rv = ipf_check(&V_ipfmain, mtod(*mp, struct ip *),
152 	    sizeof(struct ip6_hdr), ifp, !!(flags & PFIL_OUT), mp);
153 	CURVNET_RESTORE();
154 
155 	return (rv == 0 ? PFIL_PASS : PFIL_DROPPED);
156 }
157 # endif
158 #if	defined(IPFILTER_LKM)
159 int ipf_identify(char *s)
160 {
161 	if (strcmp(s, "ipl") == 0)
162 		return (1);
163 	return (0);
164 }
165 #endif /* IPFILTER_LKM */
166 
167 
168 static void
169 ipf_timer_func(void *arg)
170 {
171 	ipf_main_softc_t *softc = arg;
172 	SPL_INT(s);
173 
174 	SPL_NET(s);
175 	READ_ENTER(&softc->ipf_global);
176 
177 	if (softc->ipf_running > 0)
178 		ipf_slowtimer(softc);
179 
180 	if (softc->ipf_running == -1 || softc->ipf_running == 1) {
181 #if 0
182 		softc->ipf_slow_ch = timeout(ipf_timer_func, softc, hz/2);
183 #endif
184 		callout_init(&softc->ipf_slow_ch, 1);
185 		callout_reset(&softc->ipf_slow_ch,
186 			(hz / IPF_HZ_DIVIDE) * IPF_HZ_MULT,
187 			ipf_timer_func, softc);
188 	}
189 	RWLOCK_EXIT(&softc->ipf_global);
190 	SPL_X(s);
191 }
192 
193 
194 int
195 ipfattach(ipf_main_softc_t *softc)
196 {
197 #ifdef USE_SPL
198 	int s;
199 #endif
200 
201 	SPL_NET(s);
202 	if (softc->ipf_running > 0) {
203 		SPL_X(s);
204 		return (EBUSY);
205 	}
206 
207 	if (ipf_init_all(softc) < 0) {
208 		SPL_X(s);
209 		return (EIO);
210 	}
211 
212 
213 	bzero((char *)V_ipfmain.ipf_selwait, sizeof(V_ipfmain.ipf_selwait));
214 	softc->ipf_running = 1;
215 
216 	if (softc->ipf_control_forwarding & 1)
217 		V_ipforwarding = 1;
218 
219 	SPL_X(s);
220 #if 0
221 	softc->ipf_slow_ch = timeout(ipf_timer_func, softc,
222 				     (hz / IPF_HZ_DIVIDE) * IPF_HZ_MULT);
223 #endif
224 	callout_init(&softc->ipf_slow_ch, 1);
225 	callout_reset(&softc->ipf_slow_ch, (hz / IPF_HZ_DIVIDE) * IPF_HZ_MULT,
226 		ipf_timer_func, softc);
227 	return (0);
228 }
229 
230 
231 /*
232  * Disable the filter by removing the hooks from the IP input/output
233  * stream.
234  */
235 int
236 ipfdetach(ipf_main_softc_t *softc)
237 {
238 #ifdef USE_SPL
239 	int s;
240 #endif
241 
242 	if (softc->ipf_control_forwarding & 2)
243 		V_ipforwarding = 0;
244 
245 	SPL_NET(s);
246 
247 #if 0
248 	if (softc->ipf_slow_ch.callout != NULL)
249 		untimeout(ipf_timer_func, softc, softc->ipf_slow_ch);
250 	bzero(&softc->ipf_slow, sizeof(softc->ipf_slow));
251 #endif
252 	callout_drain(&softc->ipf_slow_ch);
253 
254 	ipf_fini_all(softc);
255 
256 	softc->ipf_running = -2;
257 
258 	SPL_X(s);
259 
260 	return (0);
261 }
262 
263 
264 /*
265  * Filter ioctl interface.
266  */
267 int
268 ipfioctl(struct cdev *dev, ioctlcmd_t cmd, caddr_t data,
269 	int mode, struct thread *p)
270 #define	p_cred	td_ucred
271 #define	p_uid	td_ucred->cr_ruid
272 {
273 	int error = 0, unit = 0;
274 	SPL_INT(s);
275 
276 	CURVNET_SET(TD_TO_VNET(p));
277 	if (securelevel_ge(p->p_cred, 3) && (mode & FWRITE))
278 	{
279 		V_ipfmain.ipf_interror = 130001;
280 		CURVNET_RESTORE();
281 		return (EPERM);
282 	}
283 
284 	if (jailed_without_vnet(p->p_cred)) {
285 		V_ipfmain.ipf_interror = 130018;
286 		CURVNET_RESTORE();
287 		return (EOPNOTSUPP);
288 	}
289 
290 	unit = GET_MINOR(dev);
291 	if ((IPL_LOGMAX < unit) || (unit < 0)) {
292 		V_ipfmain.ipf_interror = 130002;
293 		CURVNET_RESTORE();
294 		return (ENXIO);
295 	}
296 
297 	if (V_ipfmain.ipf_running <= 0) {
298 		if (unit != IPL_LOGIPF && cmd != SIOCIPFINTERROR) {
299 			V_ipfmain.ipf_interror = 130003;
300 			CURVNET_RESTORE();
301 			return (EIO);
302 		}
303 		if (cmd != SIOCIPFGETNEXT && cmd != SIOCIPFGET &&
304 		    cmd != SIOCIPFSET && cmd != SIOCFRENB &&
305 		    cmd != SIOCGETFS && cmd != SIOCGETFF &&
306 		    cmd != SIOCIPFINTERROR) {
307 			V_ipfmain.ipf_interror = 130004;
308 			CURVNET_RESTORE();
309 			return (EIO);
310 		}
311 	}
312 
313 	SPL_NET(s);
314 
315 	error = ipf_ioctlswitch(&V_ipfmain, unit, data, cmd, mode, p->p_uid, p);
316 	CURVNET_RESTORE();
317 	if (error != -1) {
318 		SPL_X(s);
319 		return (error);
320 	}
321 
322 	SPL_X(s);
323 
324 	return (error);
325 }
326 
327 
328 /*
329  * ipf_send_reset - this could conceivably be a call to tcp_respond(), but that
330  * requires a large amount of setting up and isn't any more efficient.
331  */
332 int
333 ipf_send_reset(fr_info_t *fin)
334 {
335 	struct tcphdr *tcp, *tcp2;
336 	int tlen = 0, hlen;
337 	struct mbuf *m;
338 #ifdef USE_INET6
339 	ip6_t *ip6;
340 #endif
341 	ip_t *ip;
342 
343 	tcp = fin->fin_dp;
344 	if (tcp->th_flags & TH_RST)
345 		return (-1);		/* feedback loop */
346 
347 	if (ipf_checkl4sum(fin) == -1)
348 		return (-1);
349 
350 	tlen = fin->fin_dlen - (TCP_OFF(tcp) << 2) +
351 			((tcp->th_flags & TH_SYN) ? 1 : 0) +
352 			((tcp->th_flags & TH_FIN) ? 1 : 0);
353 
354 #ifdef USE_INET6
355 	hlen = (fin->fin_v == 6) ? sizeof(ip6_t) : sizeof(ip_t);
356 #else
357 	hlen = sizeof(ip_t);
358 #endif
359 #ifdef MGETHDR
360 	MGETHDR(m, M_NOWAIT, MT_HEADER);
361 #else
362 	MGET(m, M_NOWAIT, MT_HEADER);
363 #endif
364 	if (m == NULL)
365 		return (-1);
366 	if (sizeof(*tcp2) + hlen > MLEN) {
367 		if (!(MCLGET(m, M_NOWAIT))) {
368 			FREE_MB_T(m);
369 			return (-1);
370 		}
371 	}
372 
373 	m->m_len = sizeof(*tcp2) + hlen;
374 	m->m_data += max_linkhdr;
375 	m->m_pkthdr.len = m->m_len;
376 	m->m_pkthdr.rcvif = (struct ifnet *)0;
377 	ip = mtod(m, struct ip *);
378 	bzero((char *)ip, hlen);
379 #ifdef USE_INET6
380 	ip6 = (ip6_t *)ip;
381 #endif
382 	tcp2 = (struct tcphdr *)((char *)ip + hlen);
383 	tcp2->th_sport = tcp->th_dport;
384 	tcp2->th_dport = tcp->th_sport;
385 
386 	if (tcp->th_flags & TH_ACK) {
387 		tcp2->th_seq = tcp->th_ack;
388 		tcp2->th_flags = TH_RST;
389 		tcp2->th_ack = 0;
390 	} else {
391 		tcp2->th_seq = 0;
392 		tcp2->th_ack = ntohl(tcp->th_seq);
393 		tcp2->th_ack += tlen;
394 		tcp2->th_ack = htonl(tcp2->th_ack);
395 		tcp2->th_flags = TH_RST|TH_ACK;
396 	}
397 	TCP_X2_A(tcp2, 0);
398 	TCP_OFF_A(tcp2, sizeof(*tcp2) >> 2);
399 	tcp2->th_win = tcp->th_win;
400 	tcp2->th_sum = 0;
401 	tcp2->th_urp = 0;
402 
403 #ifdef USE_INET6
404 	if (fin->fin_v == 6) {
405 		ip6->ip6_flow = ((ip6_t *)fin->fin_ip)->ip6_flow;
406 		ip6->ip6_plen = htons(sizeof(struct tcphdr));
407 		ip6->ip6_nxt = IPPROTO_TCP;
408 		ip6->ip6_hlim = 0;
409 		ip6->ip6_src = fin->fin_dst6.in6;
410 		ip6->ip6_dst = fin->fin_src6.in6;
411 		tcp2->th_sum = in6_cksum(m, IPPROTO_TCP,
412 					 sizeof(*ip6), sizeof(*tcp2));
413 		return (ipf_send_ip(fin, m));
414 	}
415 #endif
416 	ip->ip_p = IPPROTO_TCP;
417 	ip->ip_len = htons(sizeof(struct tcphdr));
418 	ip->ip_src.s_addr = fin->fin_daddr;
419 	ip->ip_dst.s_addr = fin->fin_saddr;
420 	tcp2->th_sum = in_cksum(m, hlen + sizeof(*tcp2));
421 	ip->ip_len = htons(hlen + sizeof(*tcp2));
422 	return (ipf_send_ip(fin, m));
423 }
424 
425 
426 /*
427  * ip_len must be in network byte order when called.
428  */
429 static int
430 ipf_send_ip(fr_info_t *fin, mb_t *m)
431 {
432 	fr_info_t fnew;
433 	ip_t *ip, *oip;
434 	int hlen;
435 
436 	ip = mtod(m, ip_t *);
437 	bzero((char *)&fnew, sizeof(fnew));
438 	fnew.fin_main_soft = fin->fin_main_soft;
439 
440 	IP_V_A(ip, fin->fin_v);
441 	switch (fin->fin_v)
442 	{
443 	case 4 :
444 		oip = fin->fin_ip;
445 		hlen = sizeof(*oip);
446 		fnew.fin_v = 4;
447 		fnew.fin_p = ip->ip_p;
448 		fnew.fin_plen = ntohs(ip->ip_len);
449 		IP_HL_A(ip, sizeof(*oip) >> 2);
450 		ip->ip_tos = oip->ip_tos;
451 		ip->ip_id = fin->fin_ip->ip_id;
452 		ip->ip_off = htons(V_path_mtu_discovery ? IP_DF : 0);
453 		ip->ip_ttl = V_ip_defttl;
454 		ip->ip_sum = 0;
455 		break;
456 #ifdef USE_INET6
457 	case 6 :
458 	{
459 		ip6_t *ip6 = (ip6_t *)ip;
460 
461 		ip6->ip6_vfc = 0x60;
462 		ip6->ip6_hlim = IPDEFTTL;
463 
464 		hlen = sizeof(*ip6);
465 		fnew.fin_p = ip6->ip6_nxt;
466 		fnew.fin_v = 6;
467 		fnew.fin_plen = ntohs(ip6->ip6_plen) + hlen;
468 		break;
469 	}
470 #endif
471 	default :
472 		return (EINVAL);
473 	}
474 #ifdef IPSEC_SUPPORT
475 	m->m_pkthdr.rcvif = NULL;
476 #endif
477 
478 	fnew.fin_ifp = fin->fin_ifp;
479 	fnew.fin_flx = FI_NOCKSUM;
480 	fnew.fin_m = m;
481 	fnew.fin_ip = ip;
482 	fnew.fin_mp = &m;
483 	fnew.fin_hlen = hlen;
484 	fnew.fin_dp = (char *)ip + hlen;
485 	(void) ipf_makefrip(hlen, ip, &fnew);
486 
487 	return (ipf_fastroute(m, &m, &fnew, NULL));
488 }
489 
490 
491 int
492 ipf_send_icmp_err(int type, fr_info_t *fin, int dst)
493 {
494 	int err, hlen, xtra, iclen, ohlen, avail, code;
495 	struct in_addr dst4;
496 	struct icmp *icmp;
497 	struct mbuf *m;
498 	i6addr_t dst6;
499 	void *ifp;
500 #ifdef USE_INET6
501 	ip6_t *ip6;
502 #endif
503 	ip_t *ip, *ip2;
504 
505 	if ((type < 0) || (type >= ICMP_MAXTYPE))
506 		return (-1);
507 
508 	code = fin->fin_icode;
509 #ifdef USE_INET6
510 	/* See NetBSD ip_fil_netbsd.c r1.4: */
511 	if ((code < 0) || (code >= sizeof(icmptoicmp6unreach)/sizeof(int)))
512 		return (-1);
513 #endif
514 
515 	if (ipf_checkl4sum(fin) == -1)
516 		return (-1);
517 #ifdef MGETHDR
518 	MGETHDR(m, M_NOWAIT, MT_HEADER);
519 #else
520 	MGET(m, M_NOWAIT, MT_HEADER);
521 #endif
522 	if (m == NULL)
523 		return (-1);
524 	avail = MHLEN;
525 
526 	xtra = 0;
527 	hlen = 0;
528 	ohlen = 0;
529 	dst4.s_addr = 0;
530 	ifp = fin->fin_ifp;
531 	if (fin->fin_v == 4) {
532 		if ((fin->fin_p == IPPROTO_ICMP) && !(fin->fin_flx & FI_SHORT))
533 			switch (ntohs(fin->fin_data[0]) >> 8)
534 			{
535 			case ICMP_ECHO :
536 			case ICMP_TSTAMP :
537 			case ICMP_IREQ :
538 			case ICMP_MASKREQ :
539 				break;
540 			default :
541 				FREE_MB_T(m);
542 				return (0);
543 			}
544 
545 		if (dst == 0) {
546 			if (ipf_ifpaddr(&V_ipfmain, 4, FRI_NORMAL, ifp,
547 					&dst6, NULL) == -1) {
548 				FREE_MB_T(m);
549 				return (-1);
550 			}
551 			dst4 = dst6.in4;
552 		} else
553 			dst4.s_addr = fin->fin_daddr;
554 
555 		hlen = sizeof(ip_t);
556 		ohlen = fin->fin_hlen;
557 		iclen = hlen + offsetof(struct icmp, icmp_ip) + ohlen;
558 		if (fin->fin_hlen < fin->fin_plen)
559 			xtra = MIN(fin->fin_dlen, 8);
560 		else
561 			xtra = 0;
562 	}
563 
564 #ifdef USE_INET6
565 	else if (fin->fin_v == 6) {
566 		hlen = sizeof(ip6_t);
567 		ohlen = sizeof(ip6_t);
568 		iclen = hlen + offsetof(struct icmp, icmp_ip) + ohlen;
569 		type = icmptoicmp6types[type];
570 		if (type == ICMP6_DST_UNREACH)
571 			code = icmptoicmp6unreach[code];
572 
573 		if (iclen + max_linkhdr + fin->fin_plen > avail) {
574 			if (!(MCLGET(m, M_NOWAIT))) {
575 				FREE_MB_T(m);
576 				return (-1);
577 			}
578 			avail = MCLBYTES;
579 		}
580 		xtra = MIN(fin->fin_plen, avail - iclen - max_linkhdr);
581 		xtra = MIN(xtra, IPV6_MMTU - iclen);
582 		if (dst == 0) {
583 			if (ipf_ifpaddr(&V_ipfmain, 6, FRI_NORMAL, ifp,
584 					&dst6, NULL) == -1) {
585 				FREE_MB_T(m);
586 				return (-1);
587 			}
588 		} else
589 			dst6 = fin->fin_dst6;
590 	}
591 #endif
592 	else {
593 		FREE_MB_T(m);
594 		return (-1);
595 	}
596 
597 	avail -= (max_linkhdr + iclen);
598 	if (avail < 0) {
599 		FREE_MB_T(m);
600 		return (-1);
601 	}
602 	if (xtra > avail)
603 		xtra = avail;
604 	iclen += xtra;
605 	m->m_data += max_linkhdr;
606 	m->m_pkthdr.rcvif = (struct ifnet *)0;
607 	m->m_pkthdr.len = iclen;
608 	m->m_len = iclen;
609 	ip = mtod(m, ip_t *);
610 	icmp = (struct icmp *)((char *)ip + hlen);
611 	ip2 = (ip_t *)&icmp->icmp_ip;
612 
613 	icmp->icmp_type = type;
614 	icmp->icmp_code = fin->fin_icode;
615 	icmp->icmp_cksum = 0;
616 #ifdef icmp_nextmtu
617 	if (type == ICMP_UNREACH && fin->fin_icode == ICMP_UNREACH_NEEDFRAG) {
618 		if (fin->fin_mtu != 0) {
619 			icmp->icmp_nextmtu = htons(fin->fin_mtu);
620 
621 		} else if (ifp != NULL) {
622 			icmp->icmp_nextmtu = htons(GETIFMTU_4(ifp));
623 
624 		} else {	/* make up a number... */
625 			icmp->icmp_nextmtu = htons(fin->fin_plen - 20);
626 		}
627 	}
628 #endif
629 
630 	bcopy((char *)fin->fin_ip, (char *)ip2, ohlen);
631 
632 #ifdef USE_INET6
633 	ip6 = (ip6_t *)ip;
634 	if (fin->fin_v == 6) {
635 		ip6->ip6_flow = ((ip6_t *)fin->fin_ip)->ip6_flow;
636 		ip6->ip6_plen = htons(iclen - hlen);
637 		ip6->ip6_nxt = IPPROTO_ICMPV6;
638 		ip6->ip6_hlim = 0;
639 		ip6->ip6_src = dst6.in6;
640 		ip6->ip6_dst = fin->fin_src6.in6;
641 		if (xtra > 0)
642 			bcopy((char *)fin->fin_ip + ohlen,
643 			      (char *)&icmp->icmp_ip + ohlen, xtra);
644 		icmp->icmp_cksum = in6_cksum(m, IPPROTO_ICMPV6,
645 					     sizeof(*ip6), iclen - hlen);
646 	} else
647 #endif
648 	{
649 		ip->ip_p = IPPROTO_ICMP;
650 		ip->ip_src.s_addr = dst4.s_addr;
651 		ip->ip_dst.s_addr = fin->fin_saddr;
652 
653 		if (xtra > 0)
654 			bcopy((char *)fin->fin_ip + ohlen,
655 			      (char *)&icmp->icmp_ip + ohlen, xtra);
656 		icmp->icmp_cksum = ipf_cksum((u_short *)icmp,
657 					     sizeof(*icmp) + 8);
658 		ip->ip_len = htons(iclen);
659 		ip->ip_p = IPPROTO_ICMP;
660 	}
661 	err = ipf_send_ip(fin, m);
662 	return (err);
663 }
664 
665 
666 
667 
668 /*
669  * m0 - pointer to mbuf where the IP packet starts
670  * mpp - pointer to the mbuf pointer that is the start of the mbuf chain
671  */
672 int
673 ipf_fastroute(mb_t *m0, mb_t **mpp, fr_info_t *fin, frdest_t *fdp)
674 {
675 	register struct ip *ip, *mhip;
676 	register struct mbuf *m = *mpp;
677 	int len, off, error = 0, hlen, code;
678 	struct ifnet *ifp, *sifp;
679 	struct route ro;
680 	struct sockaddr_in *dst;
681 	const struct sockaddr *gw;
682 	struct nhop_object *nh;
683 	u_long fibnum = 0;
684 	u_short ip_off;
685 	frdest_t node;
686 	frentry_t *fr;
687 
688 #ifdef M_WRITABLE
689 	/*
690 	* HOT FIX/KLUDGE:
691 	*
692 	* If the mbuf we're about to send is not writable (because of
693 	* a cluster reference, for example) we'll need to make a copy
694 	* of it since this routine modifies the contents.
695 	*
696 	* If you have non-crappy network hardware that can transmit data
697 	* from the mbuf, rather than making a copy, this is gonna be a
698 	* problem.
699 	*/
700 	if (M_WRITABLE(m) == 0) {
701 		m0 = m_dup(m, M_NOWAIT);
702 		if (m0 != NULL) {
703 			FREE_MB_T(m);
704 			m = m0;
705 			*mpp = m;
706 		} else {
707 			error = ENOBUFS;
708 			FREE_MB_T(m);
709 			goto done;
710 		}
711 	}
712 #endif
713 
714 #ifdef USE_INET6
715 	if (fin->fin_v == 6) {
716 		/*
717 		 * currently "to <if>" and "to <if>:ip#" are not supported
718 		 * for IPv6
719 		 */
720 		return (ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL));
721 	}
722 #endif
723 
724 	hlen = fin->fin_hlen;
725 	ip = mtod(m0, struct ip *);
726 	ifp = NULL;
727 
728 	/*
729 	 * Route packet.
730 	 */
731 	bzero(&ro, sizeof (ro));
732 	dst = (struct sockaddr_in *)&ro.ro_dst;
733 	dst->sin_family = AF_INET;
734 	dst->sin_addr = ip->ip_dst;
735 	dst->sin_len = sizeof(dst);
736 	gw = (const struct sockaddr *)dst;
737 
738 	fr = fin->fin_fr;
739 	if ((fr != NULL) && !(fr->fr_flags & FR_KEEPSTATE) && (fdp != NULL) &&
740 	    (fdp->fd_type == FRD_DSTLIST)) {
741 		if (ipf_dstlist_select_node(fin, fdp->fd_ptr, NULL, &node) == 0)
742 			fdp = &node;
743 	}
744 
745 	if (fdp != NULL)
746 		ifp = fdp->fd_ptr;
747 	else
748 		ifp = fin->fin_ifp;
749 
750 	if ((ifp == NULL) && ((fr == NULL) || !(fr->fr_flags & FR_FASTROUTE))) {
751 		error = -2;
752 		goto bad;
753 	}
754 
755 	if ((fdp != NULL) && (fdp->fd_ip.s_addr != 0))
756 		dst->sin_addr = fdp->fd_ip;
757 
758 	fibnum = M_GETFIB(m0);
759 	NET_EPOCH_ASSERT();
760 	nh = fib4_lookup(fibnum, dst->sin_addr, 0, NHR_NONE, 0);
761 	if (nh == NULL) {
762 		if (in_localaddr(ip->ip_dst))
763 			error = EHOSTUNREACH;
764 		else
765 			error = ENETUNREACH;
766 		goto bad;
767 	}
768 
769 	if (ifp == NULL)
770 		ifp = nh->nh_ifp;
771 	if (nh->nh_flags & NHF_GATEWAY) {
772 		gw = &nh->gw_sa;
773 		ro.ro_flags |= RT_HAS_GW;
774 	}
775 
776 	/*
777 	 * For input packets which are being "fastrouted", they won't
778 	 * go back through output filtering and miss their chance to get
779 	 * NAT'd and counted.  Duplicated packets aren't considered to be
780 	 * part of the normal packet stream, so do not NAT them or pass
781 	 * them through stateful checking, etc.
782 	 */
783 	if ((fdp != &fr->fr_dif) && (fin->fin_out == 0)) {
784 		sifp = fin->fin_ifp;
785 		fin->fin_ifp = ifp;
786 		fin->fin_out = 1;
787 		(void) ipf_acctpkt(fin, NULL);
788 		fin->fin_fr = NULL;
789 		if (!fr || !(fr->fr_flags & FR_RETMASK)) {
790 			u_32_t pass;
791 
792 			(void) ipf_state_check(fin, &pass);
793 		}
794 
795 		switch (ipf_nat_checkout(fin, NULL))
796 		{
797 		case 0 :
798 			break;
799 		case 1 :
800 			ip->ip_sum = 0;
801 			break;
802 		case -1 :
803 			error = -1;
804 			goto bad;
805 			break;
806 		}
807 
808 		fin->fin_ifp = sifp;
809 		fin->fin_out = 0;
810 	} else
811 		ip->ip_sum = 0;
812 	/*
813 	 * If small enough for interface, can just send directly.
814 	 */
815 	if (ntohs(ip->ip_len) <= ifp->if_mtu) {
816 		if (!ip->ip_sum)
817 			ip->ip_sum = in_cksum(m, hlen);
818 		error = (*ifp->if_output)(ifp, m, gw, &ro);
819 		goto done;
820 	}
821 	/*
822 	 * Too large for interface; fragment if possible.
823 	 * Must be able to put at least 8 bytes per fragment.
824 	 */
825 	ip_off = ntohs(ip->ip_off);
826 	if (ip_off & IP_DF) {
827 		error = EMSGSIZE;
828 		goto bad;
829 	}
830 	len = (ifp->if_mtu - hlen) &~ 7;
831 	if (len < 8) {
832 		error = EMSGSIZE;
833 		goto bad;
834 	}
835 
836     {
837 	int mhlen, firstlen = len;
838 	struct mbuf **mnext = &m->m_act;
839 
840 	/*
841 	 * Loop through length of segment after first fragment,
842 	 * make new header and copy data of each part and link onto chain.
843 	 */
844 	m0 = m;
845 	mhlen = sizeof (struct ip);
846 	for (off = hlen + len; off < ntohs(ip->ip_len); off += len) {
847 #ifdef MGETHDR
848 		MGETHDR(m, M_NOWAIT, MT_HEADER);
849 #else
850 		MGET(m, M_NOWAIT, MT_HEADER);
851 #endif
852 		if (m == NULL) {
853 			m = m0;
854 			error = ENOBUFS;
855 			goto bad;
856 		}
857 		m->m_data += max_linkhdr;
858 		mhip = mtod(m, struct ip *);
859 		bcopy((char *)ip, (char *)mhip, sizeof(*ip));
860 		if (hlen > sizeof (struct ip)) {
861 			mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
862 			IP_HL_A(mhip, mhlen >> 2);
863 		}
864 		m->m_len = mhlen;
865 		mhip->ip_off = ((off - hlen) >> 3) + ip_off;
866 		if (off + len >= ntohs(ip->ip_len))
867 			len = ntohs(ip->ip_len) - off;
868 		else
869 			mhip->ip_off |= IP_MF;
870 		mhip->ip_len = htons((u_short)(len + mhlen));
871 		*mnext = m;
872 		m->m_next = m_copym(m0, off, len, M_NOWAIT);
873 		if (m->m_next == 0) {
874 			error = ENOBUFS;	/* ??? */
875 			goto sendorfree;
876 		}
877 		m->m_pkthdr.len = mhlen + len;
878 		m->m_pkthdr.rcvif = NULL;
879 		mhip->ip_off = htons((u_short)mhip->ip_off);
880 		mhip->ip_sum = 0;
881 		mhip->ip_sum = in_cksum(m, mhlen);
882 		mnext = &m->m_act;
883 	}
884 	/*
885 	 * Update first fragment by trimming what's been copied out
886 	 * and updating header, then send each fragment (in order).
887 	 */
888 	m_adj(m0, hlen + firstlen - ip->ip_len);
889 	ip->ip_len = htons((u_short)(hlen + firstlen));
890 	ip->ip_off = htons((u_short)IP_MF);
891 	ip->ip_sum = 0;
892 	ip->ip_sum = in_cksum(m0, hlen);
893 sendorfree:
894 	for (m = m0; m; m = m0) {
895 		m0 = m->m_act;
896 		m->m_act = 0;
897 		if (error == 0)
898 			error = (*ifp->if_output)(ifp, m, gw, &ro);
899 		else
900 			FREE_MB_T(m);
901 	}
902     }
903 done:
904 	if (!error)
905 		V_ipfmain.ipf_frouteok[0]++;
906 	else
907 		V_ipfmain.ipf_frouteok[1]++;
908 
909 	return (0);
910 bad:
911 	if (error == EMSGSIZE) {
912 		sifp = fin->fin_ifp;
913 		code = fin->fin_icode;
914 		fin->fin_icode = ICMP_UNREACH_NEEDFRAG;
915 		fin->fin_ifp = ifp;
916 		(void) ipf_send_icmp_err(ICMP_UNREACH, fin, 1);
917 		fin->fin_ifp = sifp;
918 		fin->fin_icode = code;
919 	}
920 	FREE_MB_T(m);
921 	goto done;
922 }
923 
924 
925 int
926 ipf_verifysrc(fr_info_t *fin)
927 {
928 	struct nhop_object *nh;
929 
930 	NET_EPOCH_ASSERT();
931 	nh = fib4_lookup(RT_DEFAULT_FIB, fin->fin_src, 0, NHR_NONE, 0);
932 	if (nh == NULL)
933 		return (0);
934 	return (fin->fin_ifp == nh->nh_ifp);
935 }
936 
937 
938 /*
939  * return the first IP Address associated with an interface
940  */
941 int
942 ipf_ifpaddr(ipf_main_softc_t *softc, int v, int atype, void *ifptr,
943 	i6addr_t *inp, i6addr_t *inpmask)
944 {
945 #ifdef USE_INET6
946 	struct in6_addr *ia6 = NULL;
947 #endif
948 	struct sockaddr *sock, *mask;
949 	struct sockaddr_in *sin;
950 	struct ifaddr *ifa;
951 	struct ifnet *ifp;
952 
953 	if ((ifptr == NULL) || (ifptr == (void *)-1))
954 		return (-1);
955 
956 	sin = NULL;
957 	ifp = ifptr;
958 
959 	if (v == 4)
960 		inp->in4.s_addr = 0;
961 #ifdef USE_INET6
962 	else if (v == 6)
963 		bzero((char *)inp, sizeof(*inp));
964 #endif
965 	ifa = CK_STAILQ_FIRST(&ifp->if_addrhead);
966 
967 	sock = ifa->ifa_addr;
968 	while (sock != NULL && ifa != NULL) {
969 		sin = (struct sockaddr_in *)sock;
970 		if ((v == 4) && (sin->sin_family == AF_INET))
971 			break;
972 #ifdef USE_INET6
973 		if ((v == 6) && (sin->sin_family == AF_INET6)) {
974 			ia6 = &((struct sockaddr_in6 *)sin)->sin6_addr;
975 			if (!IN6_IS_ADDR_LINKLOCAL(ia6) &&
976 			    !IN6_IS_ADDR_LOOPBACK(ia6))
977 				break;
978 		}
979 #endif
980 		ifa = CK_STAILQ_NEXT(ifa, ifa_link);
981 		if (ifa != NULL)
982 			sock = ifa->ifa_addr;
983 	}
984 
985 	if (ifa == NULL || sin == NULL)
986 		return (-1);
987 
988 	mask = ifa->ifa_netmask;
989 	if (atype == FRI_BROADCAST)
990 		sock = ifa->ifa_broadaddr;
991 	else if (atype == FRI_PEERADDR)
992 		sock = ifa->ifa_dstaddr;
993 
994 	if (sock == NULL)
995 		return (-1);
996 
997 #ifdef USE_INET6
998 	if (v == 6) {
999 		return (ipf_ifpfillv6addr(atype, (struct sockaddr_in6 *)sock,
1000 					 (struct sockaddr_in6 *)mask,
1001 					 inp, inpmask));
1002 	}
1003 #endif
1004 	return (ipf_ifpfillv4addr(atype, (struct sockaddr_in *)sock,
1005 				 (struct sockaddr_in *)mask,
1006 				 &inp->in4, &inpmask->in4));
1007 }
1008 
1009 
1010 u_32_t
1011 ipf_newisn(fr_info_t *fin)
1012 {
1013 	u_32_t newiss;
1014 	newiss = arc4random();
1015 	return (newiss);
1016 }
1017 
1018 
1019 int
1020 ipf_checkv4sum(fr_info_t *fin)
1021 {
1022 #ifdef CSUM_DATA_VALID
1023 	int manual = 0;
1024 	u_short sum;
1025 	ip_t *ip;
1026 	mb_t *m;
1027 
1028 	if ((fin->fin_flx & FI_NOCKSUM) != 0)
1029 		return (0);
1030 
1031 	if ((fin->fin_flx & FI_SHORT) != 0)
1032 		return (1);
1033 
1034 	if (fin->fin_cksum != FI_CK_NEEDED)
1035 		return (fin->fin_cksum > FI_CK_NEEDED) ? 0 : -1;
1036 
1037 	m = fin->fin_m;
1038 	if (m == NULL) {
1039 		manual = 1;
1040 		goto skipauto;
1041 	}
1042 	ip = fin->fin_ip;
1043 
1044 	if ((m->m_pkthdr.csum_flags & (CSUM_IP_CHECKED|CSUM_IP_VALID)) ==
1045 	    CSUM_IP_CHECKED) {
1046 		fin->fin_cksum = FI_CK_BAD;
1047 		fin->fin_flx |= FI_BAD;
1048 		DT2(ipf_fi_bad_checkv4sum_csum_ip_checked, fr_info_t *, fin, u_int, m->m_pkthdr.csum_flags & (CSUM_IP_CHECKED|CSUM_IP_VALID));
1049 		return (-1);
1050 	}
1051 	if (m->m_pkthdr.csum_flags & CSUM_DATA_VALID) {
1052 		/* Depending on the driver, UDP may have zero checksum */
1053 		if (fin->fin_p == IPPROTO_UDP && (fin->fin_flx &
1054 		    (FI_FRAG|FI_SHORT|FI_BAD)) == 0) {
1055 			udphdr_t *udp = fin->fin_dp;
1056 			if (udp->uh_sum == 0) {
1057 				/*
1058 				 * we're good no matter what the hardware
1059 				 * checksum flags and csum_data say (handling
1060 				 * of csum_data for zero UDP checksum is not
1061 				 * consistent across all drivers)
1062 				 */
1063 				fin->fin_cksum = 1;
1064 				return (0);
1065 			}
1066 		}
1067 
1068 		if (m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR)
1069 			sum = m->m_pkthdr.csum_data;
1070 		else
1071 			sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
1072 					htonl(m->m_pkthdr.csum_data +
1073 					fin->fin_dlen + fin->fin_p));
1074 		sum ^= 0xffff;
1075 		if (sum != 0) {
1076 			fin->fin_cksum = FI_CK_BAD;
1077 			fin->fin_flx |= FI_BAD;
1078 			DT2(ipf_fi_bad_checkv4sum_sum, fr_info_t *, fin, u_int, sum);
1079 		} else {
1080 			fin->fin_cksum = FI_CK_SUMOK;
1081 			return (0);
1082 		}
1083 	} else {
1084 		if (m->m_pkthdr.csum_flags == CSUM_DELAY_DATA) {
1085 			fin->fin_cksum = FI_CK_L4FULL;
1086 			return (0);
1087 		} else if (m->m_pkthdr.csum_flags == CSUM_TCP ||
1088 			   m->m_pkthdr.csum_flags == CSUM_UDP ||
1089 			   m->m_pkthdr.csum_flags == CSUM_IP) {
1090 			fin->fin_cksum = FI_CK_L4PART;
1091 			return (0);
1092 		} else {
1093 			manual = 1;
1094 		}
1095 	}
1096 skipauto:
1097 	if (manual != 0) {
1098 		if (ipf_checkl4sum(fin) == -1) {
1099 			fin->fin_flx |= FI_BAD;
1100 			DT2(ipf_fi_bad_checkv4sum_manual, fr_info_t *, fin, u_int, manual);
1101 			return (-1);
1102 		}
1103 	}
1104 #else
1105 	if (ipf_checkl4sum(fin) == -1) {
1106 		fin->fin_flx |= FI_BAD;
1107 		DT2(ipf_fi_bad_checkv4sum_checkl4sum, fr_info_t *, fin, u_int, -1);
1108 		return (-1);
1109 	}
1110 #endif
1111 	return (0);
1112 }
1113 
1114 
1115 #ifdef USE_INET6
1116 int
1117 ipf_checkv6sum(fr_info_t *fin)
1118 {
1119 	if ((fin->fin_flx & FI_NOCKSUM) != 0) {
1120 		DT(ipf_checkv6sum_fi_nocksum);
1121 		return (0);
1122 	}
1123 
1124 	if ((fin->fin_flx & FI_SHORT) != 0) {
1125 		DT(ipf_checkv6sum_fi_short);
1126 		return (1);
1127 	}
1128 
1129 	if (fin->fin_cksum != FI_CK_NEEDED) {
1130 		DT(ipf_checkv6sum_fi_ck_needed);
1131 		return (fin->fin_cksum > FI_CK_NEEDED) ? 0 : -1;
1132 	}
1133 
1134 	if (ipf_checkl4sum(fin) == -1) {
1135 		fin->fin_flx |= FI_BAD;
1136 		DT2(ipf_fi_bad_checkv6sum_checkl4sum, fr_info_t *, fin, u_int, -1);
1137 		return (-1);
1138 	}
1139 	return (0);
1140 }
1141 #endif /* USE_INET6 */
1142 
1143 
1144 size_t
1145 mbufchainlen(struct mbuf *m0)
1146 {
1147 	size_t len;
1148 
1149 	if ((m0->m_flags & M_PKTHDR) != 0) {
1150 		len = m0->m_pkthdr.len;
1151 	} else {
1152 		struct mbuf *m;
1153 
1154 		for (m = m0, len = 0; m != NULL; m = m->m_next)
1155 			len += m->m_len;
1156 	}
1157 	return (len);
1158 }
1159 
1160 
1161 /* ------------------------------------------------------------------------ */
1162 /* Function:    ipf_pullup                                                  */
1163 /* Returns:     NULL == pullup failed, else pointer to protocol header      */
1164 /* Parameters:  xmin(I)- pointer to buffer where data packet starts         */
1165 /*              fin(I) - pointer to packet information                      */
1166 /*              len(I) - number of bytes to pullup                          */
1167 /*                                                                          */
1168 /* Attempt to move at least len bytes (from the start of the buffer) into a */
1169 /* single buffer for ease of access.  Operating system native functions are */
1170 /* used to manage buffers - if necessary.  If the entire packet ends up in  */
1171 /* a single buffer, set the FI_COALESCE flag even though ipf_coalesce() has */
1172 /* not been called.  Both fin_ip and fin_dp are updated before exiting _IF_ */
1173 /* and ONLY if the pullup succeeds.                                         */
1174 /*                                                                          */
1175 /* We assume that 'xmin' is a pointer to a buffer that is part of the chain */
1176 /* of buffers that starts at *fin->fin_mp.                                  */
1177 /* ------------------------------------------------------------------------ */
1178 ip_t *
1179 ipf_pullup(mb_t *xmin, fr_info_t *fin, int len)
1180 {
1181 	int dpoff, ipoff;
1182 	mb_t *m = xmin;
1183 	ip_t *ip;
1184 
1185 	if (m == NULL)
1186 		return (NULL);
1187 
1188 	ip = fin->fin_ip;
1189 	if ((fin->fin_flx & FI_COALESCE) != 0)
1190 		return (ip);
1191 
1192 	ipoff = fin->fin_ipoff;
1193 	if (fin->fin_dp != NULL)
1194 		dpoff = (char *)fin->fin_dp - (char *)ip;
1195 	else
1196 		dpoff = 0;
1197 
1198 	if (M_LEN(m) < len) {
1199 		mb_t *n = *fin->fin_mp;
1200 		/*
1201 		 * Assume that M_PKTHDR is set and just work with what is left
1202 		 * rather than check..
1203 		 * Should not make any real difference, anyway.
1204 		 */
1205 		if (m != n) {
1206 			/*
1207 			 * Record the mbuf that points to the mbuf that we're
1208 			 * about to go to work on so that we can update the
1209 			 * m_next appropriately later.
1210 			 */
1211 			for (; n->m_next != m; n = n->m_next)
1212 				;
1213 		} else {
1214 			n = NULL;
1215 		}
1216 
1217 #ifdef MHLEN
1218 		if (len > MHLEN)
1219 #else
1220 		if (len > MLEN)
1221 #endif
1222 		{
1223 #ifdef HAVE_M_PULLDOWN
1224 			if (m_pulldown(m, 0, len, NULL) == NULL)
1225 				m = NULL;
1226 #else
1227 			FREE_MB_T(*fin->fin_mp);
1228 			m = NULL;
1229 			n = NULL;
1230 #endif
1231 		} else
1232 		{
1233 
1234 			m = m_pullup(m, len);
1235 		}
1236 		if (n != NULL)
1237 			n->m_next = m;
1238 		if (m == NULL) {
1239 			/*
1240 			 * When n is non-NULL, it indicates that m pointed to
1241 			 * a sub-chain (tail) of the mbuf and that the head
1242 			 * of this chain has not yet been free'd.
1243 			 */
1244 			if (n != NULL) {
1245 				FREE_MB_T(*fin->fin_mp);
1246 			}
1247 
1248 			*fin->fin_mp = NULL;
1249 			fin->fin_m = NULL;
1250 			return (NULL);
1251 		}
1252 
1253 		if (n == NULL)
1254 			*fin->fin_mp = m;
1255 
1256 		while (M_LEN(m) == 0) {
1257 			m = m->m_next;
1258 		}
1259 		fin->fin_m = m;
1260 		ip = MTOD(m, ip_t *) + ipoff;
1261 
1262 		fin->fin_ip = ip;
1263 		if (fin->fin_dp != NULL)
1264 			fin->fin_dp = (char *)fin->fin_ip + dpoff;
1265 		if (fin->fin_fraghdr != NULL)
1266 			fin->fin_fraghdr = (char *)ip +
1267 					   ((char *)fin->fin_fraghdr -
1268 					    (char *)fin->fin_ip);
1269 	}
1270 
1271 	if (len == fin->fin_plen)
1272 		fin->fin_flx |= FI_COALESCE;
1273 	return (ip);
1274 }
1275 
1276 
1277 int
1278 ipf_inject(fr_info_t *fin, mb_t *m)
1279 {
1280 	struct epoch_tracker et;
1281 	int error = 0;
1282 
1283 	NET_EPOCH_ENTER(et);
1284 	if (fin->fin_out == 0) {
1285 		netisr_dispatch(NETISR_IP, m);
1286 	} else {
1287 		fin->fin_ip->ip_len = ntohs(fin->fin_ip->ip_len);
1288 		fin->fin_ip->ip_off = ntohs(fin->fin_ip->ip_off);
1289 		error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL);
1290 	}
1291 	NET_EPOCH_EXIT(et);
1292 
1293 	return (error);
1294 }
1295 
1296 VNET_DEFINE_STATIC(pfil_hook_t, ipf_inet_hook);
1297 VNET_DEFINE_STATIC(pfil_hook_t, ipf_inet6_hook);
1298 #define	V_ipf_inet_hook		VNET(ipf_inet_hook)
1299 #define	V_ipf_inet6_hook	VNET(ipf_inet6_hook)
1300 
1301 int ipf_pfil_unhook(void) {
1302 
1303 	pfil_remove_hook(V_ipf_inet_hook);
1304 
1305 #ifdef USE_INET6
1306 	pfil_remove_hook(V_ipf_inet6_hook);
1307 #endif
1308 
1309 	return (0);
1310 }
1311 
1312 int ipf_pfil_hook(void) {
1313 	int error, error6;
1314 
1315 	struct pfil_hook_args pha = {
1316 		.pa_version = PFIL_VERSION,
1317 		.pa_flags = PFIL_IN | PFIL_OUT,
1318 		.pa_modname = "ipfilter",
1319 		.pa_rulname = "default-ip4",
1320 		.pa_mbuf_chk = ipf_check_wrapper,
1321 		.pa_type = PFIL_TYPE_IP4,
1322 	};
1323 	V_ipf_inet_hook = pfil_add_hook(&pha);
1324 
1325 #ifdef USE_INET6
1326 	pha.pa_rulname = "default-ip6";
1327 	pha.pa_mbuf_chk = ipf_check_wrapper6;
1328 	pha.pa_type = PFIL_TYPE_IP6;
1329 	V_ipf_inet6_hook = pfil_add_hook(&pha);
1330 #endif
1331 
1332 	struct pfil_link_args pla = {
1333 		.pa_version = PFIL_VERSION,
1334 		.pa_flags = PFIL_IN | PFIL_OUT | PFIL_HEADPTR | PFIL_HOOKPTR,
1335 		.pa_head = V_inet_pfil_head,
1336 		.pa_hook = V_ipf_inet_hook,
1337 	};
1338 	error = pfil_link(&pla);
1339 
1340 	error6 = 0;
1341 #ifdef USE_INET6
1342 	pla.pa_head = V_inet6_pfil_head;
1343 	pla.pa_hook = V_ipf_inet6_hook;
1344 	error6 = pfil_link(&pla);
1345 #endif
1346 
1347 	if (error || error6)
1348 		error = ENODEV;
1349 	else
1350 		error = 0;
1351 
1352 	return (error);
1353 }
1354 
1355 void
1356 ipf_event_reg(void)
1357 {
1358 	V_ipf_arrivetag = EVENTHANDLER_REGISTER(ifnet_arrival_event, \
1359 					       ipf_ifevent, NULL, \
1360 					       EVENTHANDLER_PRI_ANY);
1361 	V_ipf_departtag = EVENTHANDLER_REGISTER(ifnet_departure_event, \
1362 					       ipf_ifevent, NULL, \
1363 					       EVENTHANDLER_PRI_ANY);
1364 #if 0
1365 	V_ipf_clonetag  = EVENTHANDLER_REGISTER(if_clone_event, ipf_ifevent, \
1366 					       NULL, EVENTHANDLER_PRI_ANY);
1367 #endif
1368 }
1369 
1370 void
1371 ipf_event_dereg(void)
1372 {
1373 	if (V_ipf_arrivetag != NULL) {
1374 		EVENTHANDLER_DEREGISTER(ifnet_arrival_event, V_ipf_arrivetag);
1375 	}
1376 	if (V_ipf_departtag != NULL) {
1377 		EVENTHANDLER_DEREGISTER(ifnet_departure_event, V_ipf_departtag);
1378 	}
1379 #if 0
1380 	if (V_ipf_clonetag != NULL) {
1381 		EVENTHANDLER_DEREGISTER(if_clone_event, V_ipf_clonetag);
1382 	}
1383 #endif
1384 }
1385 
1386 
1387 u_32_t
1388 ipf_random(void)
1389 {
1390 	return (arc4random());
1391 }
1392 
1393 
1394 u_int
1395 ipf_pcksum(fr_info_t *fin, int hlen, u_int sum)
1396 {
1397 	struct mbuf *m;
1398 	u_int sum2;
1399 	int off;
1400 
1401 	m = fin->fin_m;
1402 	off = (char *)fin->fin_dp - (char *)fin->fin_ip;
1403 	m->m_data += hlen;
1404 	m->m_len -= hlen;
1405 	sum2 = in_cksum(fin->fin_m, fin->fin_plen - off);
1406 	m->m_len += hlen;
1407 	m->m_data -= hlen;
1408 
1409 	/*
1410 	 * Both sum and sum2 are partial sums, so combine them together.
1411 	 */
1412 	sum += ~sum2 & 0xffff;
1413 	while (sum > 0xffff)
1414 		sum = (sum & 0xffff) + (sum >> 16);
1415 	sum2 = ~sum & 0xffff;
1416 	return (sum2);
1417 }
1418 
1419 #ifdef	USE_INET6
1420 u_int
1421 ipf_pcksum6(struct mbuf *m, ip6_t *ip6, u_int32_t off, u_int32_t len)
1422 {
1423 #ifdef	_KERNEL
1424 	int sum;
1425 
1426 	if (m->m_len < sizeof(struct ip6_hdr)) {
1427 		return (0xffff);
1428 	}
1429 
1430 	sum = in6_cksum(m, ip6->ip6_nxt, off, len);
1431 	return (sum);
1432 #else
1433 	u_short *sp;
1434 	u_int sum;
1435 
1436 	sp = (u_short *)&ip6->ip6_src;
1437 	sum = *sp++;   /* ip6_src */
1438 	sum += *sp++;
1439 	sum += *sp++;
1440 	sum += *sp++;
1441 	sum += *sp++;
1442 	sum += *sp++;
1443 	sum += *sp++;
1444 	sum += *sp++;
1445 	sum += *sp++;   /* ip6_dst */
1446 	sum += *sp++;
1447 	sum += *sp++;
1448 	sum += *sp++;
1449 	sum += *sp++;
1450 	sum += *sp++;
1451 	sum += *sp++;
1452 	sum += *sp++;
1453 	return (ipf_pcksum(fin, off, sum));
1454 #endif
1455 }
1456 #endif
1457 
1458 void
1459 ipf_fbsd_kenv_get(ipf_main_softc_t *softc)
1460 {
1461 	TUNABLE_INT_FETCH("net.inet.ipf.large_nat",
1462 		&softc->ipf_large_nat);
1463 }
1464