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