ip_fil_freebsd.c revision 341740 
1/*	$FreeBSD: stable/10/sys/contrib/ipfilter/netinet/ip_fil_freebsd.c 341740 2018-12-08 17:50:00Z cy $	*/
2
3/*
4 * Copyright (C) 2012 by Darren Reed.
5 *
6 * See the IPFILTER.LICENCE file for details on licencing.
7 */
8#if !defined(lint)
9static const char sccsid[] = "@(#)ip_fil.c	2.41 6/5/96 (C) 1993-2000 Darren Reed";
10static const char rcsid[] = "@(#)$Id$";
11#endif
12
13#if defined(KERNEL) || defined(_KERNEL)
14# undef KERNEL
15# undef _KERNEL
16# define	KERNEL	1
17# define	_KERNEL	1
18#endif
19#if defined(__FreeBSD_version) && (__FreeBSD_version >= 400000) && \
20    !defined(KLD_MODULE) && !defined(IPFILTER_LKM)
21# include "opt_inet6.h"
22#endif
23#if defined(__FreeBSD_version) && (__FreeBSD_version >= 440000) && \
24    !defined(KLD_MODULE) && !defined(IPFILTER_LKM)
25# include "opt_random_ip_id.h"
26#endif
27#include <sys/param.h>
28#include <sys/errno.h>
29#include <sys/types.h>
30#include <sys/file.h>
31# include <sys/fcntl.h>
32# include <sys/filio.h>
33#include <sys/time.h>
34#include <sys/systm.h>
35# include <sys/dirent.h>
36#if defined(__FreeBSD_version) && (__FreeBSD_version >= 800000)
37#include <sys/jail.h>
38#endif
39# include <sys/mbuf.h>
40# include <sys/sockopt.h>
41#if !defined(__hpux)
42# include <sys/mbuf.h>
43#endif
44#include <sys/socket.h>
45# include <sys/selinfo.h>
46# include <netinet/tcp_var.h>
47
48#include <net/if.h>
49# include <net/if_var.h>
50#  include <net/netisr.h>
51#include <net/route.h>
52#include <netinet/in.h>
53#include <netinet/in_var.h>
54#include <netinet/in_systm.h>
55#include <netinet/ip.h>
56#include <netinet/ip_var.h>
57#include <netinet/tcp.h>
58#if defined(__FreeBSD_version) && (__FreeBSD_version >= 800000)
59#include <net/vnet.h>
60#else
61#define CURVNET_SET(arg)
62#define CURVNET_RESTORE()
63#endif
64#include <netinet/udp.h>
65#include <netinet/tcpip.h>
66#include <netinet/ip_icmp.h>
67#include "netinet/ip_compat.h"
68#ifdef USE_INET6
69# include <netinet/icmp6.h>
70#endif
71#include "netinet/ip_fil.h"
72#include "netinet/ip_nat.h"
73#include "netinet/ip_frag.h"
74#include "netinet/ip_state.h"
75#include "netinet/ip_proxy.h"
76#include "netinet/ip_auth.h"
77#include "netinet/ip_sync.h"
78#include "netinet/ip_lookup.h"
79#include "netinet/ip_dstlist.h"
80#ifdef	IPFILTER_SCAN
81#include "netinet/ip_scan.h"
82#endif
83#include "netinet/ip_pool.h"
84# include <sys/malloc.h>
85#include <sys/kernel.h>
86#ifdef CSUM_DATA_VALID
87#include <machine/in_cksum.h>
88#endif
89extern	int	ip_optcopy __P((struct ip *, struct ip *));
90
91# ifdef IPFILTER_M_IPFILTER
92MALLOC_DEFINE(M_IPFILTER, "ipfilter", "IP Filter packet filter data structures");
93# endif
94
95
96static	u_short	ipid = 0;
97static	int	(*ipf_savep) __P((void *, ip_t *, int, void *, int, struct mbuf **));
98static	int	ipf_send_ip __P((fr_info_t *, mb_t *));
99static void	ipf_timer_func __P((void *arg));
100int		ipf_locks_done = 0;
101
102ipf_main_softc_t ipfmain;
103
104# include <sys/conf.h>
105# if defined(NETBSD_PF)
106#  include <net/pfil.h>
107# endif /* NETBSD_PF */
108/*
109 * We provide the ipf_checkp name just to minimize changes later.
110 */
111int (*ipf_checkp) __P((void *, ip_t *ip, int hlen, void *ifp, int out, mb_t **mp));
112
113
114static eventhandler_tag ipf_arrivetag, ipf_departtag, ipf_clonetag;
115
116static void ipf_ifevent(void *arg);
117
118static void ipf_ifevent(arg)
119	void *arg;
120{
121        ipf_sync(arg, NULL);
122}
123
124
125
126static int
127ipf_check_wrapper(void *arg, struct mbuf **mp, struct ifnet *ifp, int dir)
128{
129	struct ip *ip = mtod(*mp, struct ip *);
130	int rv;
131
132	/*
133	 * IPFilter expects evreything in network byte order
134	 */
135#if (__FreeBSD_version < 1000019)
136	ip->ip_len = htons(ip->ip_len);
137	ip->ip_off = htons(ip->ip_off);
138#endif
139	rv = ipf_check(&ipfmain, ip, ip->ip_hl << 2, ifp, (dir == PFIL_OUT),
140		       mp);
141#if (__FreeBSD_version < 1000019)
142	if ((rv == 0) && (*mp != NULL)) {
143		ip = mtod(*mp, struct ip *);
144		ip->ip_len = ntohs(ip->ip_len);
145		ip->ip_off = ntohs(ip->ip_off);
146	}
147#endif
148	return rv;
149}
150
151# ifdef USE_INET6
152#  include <netinet/ip6.h>
153
154static int
155ipf_check_wrapper6(void *arg, struct mbuf **mp, struct ifnet *ifp, int dir)
156{
157	return (ipf_check(&ipfmain, mtod(*mp, struct ip *),
158			  sizeof(struct ip6_hdr), ifp, (dir == PFIL_OUT), mp));
159}
160# endif
161#if	defined(IPFILTER_LKM)
162int ipf_identify(s)
163	char *s;
164{
165	if (strcmp(s, "ipl") == 0)
166		return 1;
167	return 0;
168}
169#endif /* IPFILTER_LKM */
170
171
172static void
173ipf_timer_func(arg)
174	void *arg;
175{
176	ipf_main_softc_t *softc = arg;
177	SPL_INT(s);
178
179	SPL_NET(s);
180	READ_ENTER(&softc->ipf_global);
181
182        if (softc->ipf_running > 0)
183		ipf_slowtimer(softc);
184
185	if (softc->ipf_running == -1 || softc->ipf_running == 1) {
186#if 0
187		softc->ipf_slow_ch = timeout(ipf_timer_func, softc, hz/2);
188#endif
189		callout_init(&softc->ipf_slow_ch, 1);
190		callout_reset(&softc->ipf_slow_ch,
191			(hz / IPF_HZ_DIVIDE) * IPF_HZ_MULT,
192			ipf_timer_func, softc);
193	}
194	RWLOCK_EXIT(&softc->ipf_global);
195	SPL_X(s);
196}
197
198
199int
200ipfattach(softc)
201	ipf_main_softc_t *softc;
202{
203#ifdef USE_SPL
204	int s;
205#endif
206
207	SPL_NET(s);
208	if (softc->ipf_running > 0) {
209		SPL_X(s);
210		return EBUSY;
211	}
212
213	if (ipf_init_all(softc) < 0) {
214		SPL_X(s);
215		return EIO;
216	}
217
218
219	if (ipf_checkp != ipf_check) {
220		ipf_savep = ipf_checkp;
221		ipf_checkp = ipf_check;
222	}
223
224	bzero((char *)ipfmain.ipf_selwait, sizeof(ipfmain.ipf_selwait));
225	softc->ipf_running = 1;
226
227	if (softc->ipf_control_forwarding & 1)
228		V_ipforwarding = 1;
229
230	ipid = 0;
231
232	SPL_X(s);
233#if 0
234	softc->ipf_slow_ch = timeout(ipf_timer_func, softc,
235				     (hz / IPF_HZ_DIVIDE) * IPF_HZ_MULT);
236#endif
237	callout_init(&softc->ipf_slow_ch, 1);
238	callout_reset(&softc->ipf_slow_ch, (hz / IPF_HZ_DIVIDE) * IPF_HZ_MULT,
239		ipf_timer_func, softc);
240	return 0;
241}
242
243
244/*
245 * Disable the filter by removing the hooks from the IP input/output
246 * stream.
247 */
248int
249ipfdetach(softc)
250	ipf_main_softc_t *softc;
251{
252#ifdef USE_SPL
253	int s;
254#endif
255
256	if (softc->ipf_control_forwarding & 2)
257		V_ipforwarding = 0;
258
259	SPL_NET(s);
260
261#if 0
262	if (softc->ipf_slow_ch.callout != NULL)
263		untimeout(ipf_timer_func, softc, softc->ipf_slow_ch);
264	bzero(&softc->ipf_slow, sizeof(softc->ipf_slow));
265#endif
266	callout_drain(&softc->ipf_slow_ch);
267
268#ifndef NETBSD_PF
269	if (ipf_checkp != NULL)
270		ipf_checkp = ipf_savep;
271	ipf_savep = NULL;
272#endif
273
274	ipf_fini_all(softc);
275
276	softc->ipf_running = -2;
277
278	SPL_X(s);
279
280	return 0;
281}
282
283
284/*
285 * Filter ioctl interface.
286 */
287int
288ipfioctl(dev, cmd, data, mode, p)
289	struct thread *p;
290#    define	p_cred	td_ucred
291#    define	p_uid	td_ucred->cr_ruid
292	struct cdev *dev;
293	ioctlcmd_t cmd;
294	caddr_t data;
295	int mode;
296{
297	int error = 0, unit = 0;
298	SPL_INT(s);
299
300#if (BSD >= 199306)
301        if (securelevel_ge(p->p_cred, 3) && (mode & FWRITE))
302	{
303		ipfmain.ipf_interror = 130001;
304		return EPERM;
305	}
306#endif
307
308	unit = GET_MINOR(dev);
309	if ((IPL_LOGMAX < unit) || (unit < 0)) {
310		ipfmain.ipf_interror = 130002;
311		return ENXIO;
312	}
313
314	if (ipfmain.ipf_running <= 0) {
315		if (unit != IPL_LOGIPF && cmd != SIOCIPFINTERROR) {
316			ipfmain.ipf_interror = 130003;
317			return EIO;
318		}
319		if (cmd != SIOCIPFGETNEXT && cmd != SIOCIPFGET &&
320		    cmd != SIOCIPFSET && cmd != SIOCFRENB &&
321		    cmd != SIOCGETFS && cmd != SIOCGETFF &&
322		    cmd != SIOCIPFINTERROR) {
323			ipfmain.ipf_interror = 130004;
324			return EIO;
325		}
326	}
327
328	SPL_NET(s);
329
330	CURVNET_SET(TD_TO_VNET(p));
331	error = ipf_ioctlswitch(&ipfmain, unit, data, cmd, mode, p->p_uid, p);
332	CURVNET_RESTORE();
333	if (error != -1) {
334		SPL_X(s);
335		return error;
336	}
337
338	SPL_X(s);
339
340	return error;
341}
342
343
344/*
345 * ipf_send_reset - this could conceivably be a call to tcp_respond(), but that
346 * requires a large amount of setting up and isn't any more efficient.
347 */
348int
349ipf_send_reset(fin)
350	fr_info_t *fin;
351{
352	struct tcphdr *tcp, *tcp2;
353	int tlen = 0, hlen;
354	struct mbuf *m;
355#ifdef USE_INET6
356	ip6_t *ip6;
357#endif
358	ip_t *ip;
359
360	tcp = fin->fin_dp;
361	if (tcp->th_flags & TH_RST)
362		return -1;		/* feedback loop */
363
364	if (ipf_checkl4sum(fin) == -1)
365		return -1;
366
367	tlen = fin->fin_dlen - (TCP_OFF(tcp) << 2) +
368			((tcp->th_flags & TH_SYN) ? 1 : 0) +
369			((tcp->th_flags & TH_FIN) ? 1 : 0);
370
371#ifdef USE_INET6
372	hlen = (fin->fin_v == 6) ? sizeof(ip6_t) : sizeof(ip_t);
373#else
374	hlen = sizeof(ip_t);
375#endif
376#ifdef MGETHDR
377	MGETHDR(m, M_DONTWAIT, MT_HEADER);
378#else
379	MGET(m, M_DONTWAIT, MT_HEADER);
380#endif
381	if (m == NULL)
382		return -1;
383	if (sizeof(*tcp2) + hlen > MLEN) {
384		MCLGET(m, M_DONTWAIT);
385		if ((m->m_flags & M_EXT) == 0) {
386			FREE_MB_T(m);
387			return -1;
388		}
389	}
390
391	m->m_len = sizeof(*tcp2) + hlen;
392#if (BSD >= 199103)
393	m->m_data += max_linkhdr;
394	m->m_pkthdr.len = m->m_len;
395	m->m_pkthdr.rcvif = (struct ifnet *)0;
396#endif
397	ip = mtod(m, struct ip *);
398	bzero((char *)ip, hlen);
399#ifdef USE_INET6
400	ip6 = (ip6_t *)ip;
401#endif
402	tcp2 = (struct tcphdr *)((char *)ip + hlen);
403	tcp2->th_sport = tcp->th_dport;
404	tcp2->th_dport = tcp->th_sport;
405
406	if (tcp->th_flags & TH_ACK) {
407		tcp2->th_seq = tcp->th_ack;
408		tcp2->th_flags = TH_RST;
409		tcp2->th_ack = 0;
410	} else {
411		tcp2->th_seq = 0;
412		tcp2->th_ack = ntohl(tcp->th_seq);
413		tcp2->th_ack += tlen;
414		tcp2->th_ack = htonl(tcp2->th_ack);
415		tcp2->th_flags = TH_RST|TH_ACK;
416	}
417	TCP_X2_A(tcp2, 0);
418	TCP_OFF_A(tcp2, sizeof(*tcp2) >> 2);
419	tcp2->th_win = tcp->th_win;
420	tcp2->th_sum = 0;
421	tcp2->th_urp = 0;
422
423#ifdef USE_INET6
424	if (fin->fin_v == 6) {
425		ip6->ip6_flow = ((ip6_t *)fin->fin_ip)->ip6_flow;
426		ip6->ip6_plen = htons(sizeof(struct tcphdr));
427		ip6->ip6_nxt = IPPROTO_TCP;
428		ip6->ip6_hlim = 0;
429		ip6->ip6_src = fin->fin_dst6.in6;
430		ip6->ip6_dst = fin->fin_src6.in6;
431		tcp2->th_sum = in6_cksum(m, IPPROTO_TCP,
432					 sizeof(*ip6), sizeof(*tcp2));
433		return ipf_send_ip(fin, m);
434	}
435#endif
436	ip->ip_p = IPPROTO_TCP;
437	ip->ip_len = htons(sizeof(struct tcphdr));
438	ip->ip_src.s_addr = fin->fin_daddr;
439	ip->ip_dst.s_addr = fin->fin_saddr;
440	tcp2->th_sum = in_cksum(m, hlen + sizeof(*tcp2));
441	ip->ip_len = htons(hlen + sizeof(*tcp2));
442	return ipf_send_ip(fin, m);
443}
444
445
446/*
447 * ip_len must be in network byte order when called.
448 */
449static int
450ipf_send_ip(fin, m)
451	fr_info_t *fin;
452	mb_t *m;
453{
454	fr_info_t fnew;
455	ip_t *ip, *oip;
456	int hlen;
457
458	ip = mtod(m, ip_t *);
459	bzero((char *)&fnew, sizeof(fnew));
460	fnew.fin_main_soft = fin->fin_main_soft;
461
462	IP_V_A(ip, fin->fin_v);
463	switch (fin->fin_v)
464	{
465	case 4 :
466		oip = fin->fin_ip;
467		hlen = sizeof(*oip);
468		fnew.fin_v = 4;
469		fnew.fin_p = ip->ip_p;
470		fnew.fin_plen = ntohs(ip->ip_len);
471		IP_HL_A(ip, sizeof(*oip) >> 2);
472		ip->ip_tos = oip->ip_tos;
473		ip->ip_id = fin->fin_ip->ip_id;
474		ip->ip_off = htons(V_path_mtu_discovery ? IP_DF : 0);
475		ip->ip_ttl = V_ip_defttl;
476		ip->ip_sum = 0;
477		break;
478#ifdef USE_INET6
479	case 6 :
480	{
481		ip6_t *ip6 = (ip6_t *)ip;
482
483		ip6->ip6_vfc = 0x60;
484		ip6->ip6_hlim = IPDEFTTL;
485
486		hlen = sizeof(*ip6);
487		fnew.fin_p = ip6->ip6_nxt;
488		fnew.fin_v = 6;
489		fnew.fin_plen = ntohs(ip6->ip6_plen) + hlen;
490		break;
491	}
492#endif
493	default :
494		return EINVAL;
495	}
496#ifdef IPSEC
497	m->m_pkthdr.rcvif = NULL;
498#endif
499
500	fnew.fin_ifp = fin->fin_ifp;
501	fnew.fin_flx = FI_NOCKSUM;
502	fnew.fin_m = m;
503	fnew.fin_ip = ip;
504	fnew.fin_mp = &m;
505	fnew.fin_hlen = hlen;
506	fnew.fin_dp = (char *)ip + hlen;
507	(void) ipf_makefrip(hlen, ip, &fnew);
508
509	return ipf_fastroute(m, &m, &fnew, NULL);
510}
511
512
513int
514ipf_send_icmp_err(type, fin, dst)
515	int type;
516	fr_info_t *fin;
517	int dst;
518{
519	int err, hlen, xtra, iclen, ohlen, avail, code;
520	struct in_addr dst4;
521	struct icmp *icmp;
522	struct mbuf *m;
523	i6addr_t dst6;
524	void *ifp;
525#ifdef USE_INET6
526	ip6_t *ip6;
527#endif
528	ip_t *ip, *ip2;
529
530	if ((type < 0) || (type >= ICMP_MAXTYPE))
531		return -1;
532
533	code = fin->fin_icode;
534#ifdef USE_INET6
535	/* See NetBSD ip_fil_netbsd.c r1.4: */
536	if ((code < 0) || (code >= sizeof(icmptoicmp6unreach)/sizeof(int)))
537		return -1;
538#endif
539
540	if (ipf_checkl4sum(fin) == -1)
541		return -1;
542#ifdef MGETHDR
543	MGETHDR(m, M_DONTWAIT, MT_HEADER);
544#else
545	MGET(m, M_DONTWAIT, MT_HEADER);
546#endif
547	if (m == NULL)
548		return -1;
549	avail = MHLEN;
550
551	xtra = 0;
552	hlen = 0;
553	ohlen = 0;
554	dst4.s_addr = 0;
555	ifp = fin->fin_ifp;
556	if (fin->fin_v == 4) {
557		if ((fin->fin_p == IPPROTO_ICMP) && !(fin->fin_flx & FI_SHORT))
558			switch (ntohs(fin->fin_data[0]) >> 8)
559			{
560			case ICMP_ECHO :
561			case ICMP_TSTAMP :
562			case ICMP_IREQ :
563			case ICMP_MASKREQ :
564				break;
565			default :
566				FREE_MB_T(m);
567				return 0;
568			}
569
570		if (dst == 0) {
571			if (ipf_ifpaddr(&ipfmain, 4, FRI_NORMAL, ifp,
572					&dst6, NULL) == -1) {
573				FREE_MB_T(m);
574				return -1;
575			}
576			dst4 = dst6.in4;
577		} else
578			dst4.s_addr = fin->fin_daddr;
579
580		hlen = sizeof(ip_t);
581		ohlen = fin->fin_hlen;
582		iclen = hlen + offsetof(struct icmp, icmp_ip) + ohlen;
583		if (fin->fin_hlen < fin->fin_plen)
584			xtra = MIN(fin->fin_dlen, 8);
585		else
586			xtra = 0;
587	}
588
589#ifdef USE_INET6
590	else if (fin->fin_v == 6) {
591		hlen = sizeof(ip6_t);
592		ohlen = sizeof(ip6_t);
593		iclen = hlen + offsetof(struct icmp, icmp_ip) + ohlen;
594		type = icmptoicmp6types[type];
595		if (type == ICMP6_DST_UNREACH)
596			code = icmptoicmp6unreach[code];
597
598		if (iclen + max_linkhdr + fin->fin_plen > avail) {
599			MCLGET(m, M_DONTWAIT);
600			if ((m->m_flags & M_EXT) == 0) {
601				FREE_MB_T(m);
602				return -1;
603			}
604			avail = MCLBYTES;
605		}
606		xtra = MIN(fin->fin_plen, avail - iclen - max_linkhdr);
607		xtra = MIN(xtra, IPV6_MMTU - iclen);
608		if (dst == 0) {
609			if (ipf_ifpaddr(&ipfmain, 6, FRI_NORMAL, ifp,
610					&dst6, NULL) == -1) {
611				FREE_MB_T(m);
612				return -1;
613			}
614		} else
615			dst6 = fin->fin_dst6;
616	}
617#endif
618	else {
619		FREE_MB_T(m);
620		return -1;
621	}
622
623	avail -= (max_linkhdr + iclen);
624	if (avail < 0) {
625		FREE_MB_T(m);
626		return -1;
627	}
628	if (xtra > avail)
629		xtra = avail;
630	iclen += xtra;
631	m->m_data += max_linkhdr;
632	m->m_pkthdr.rcvif = (struct ifnet *)0;
633	m->m_pkthdr.len = iclen;
634	m->m_len = iclen;
635	ip = mtod(m, ip_t *);
636	icmp = (struct icmp *)((char *)ip + hlen);
637	ip2 = (ip_t *)&icmp->icmp_ip;
638
639	icmp->icmp_type = type;
640	icmp->icmp_code = fin->fin_icode;
641	icmp->icmp_cksum = 0;
642#ifdef icmp_nextmtu
643	if (type == ICMP_UNREACH && fin->fin_icode == ICMP_UNREACH_NEEDFRAG) {
644		if (fin->fin_mtu != 0) {
645			icmp->icmp_nextmtu = htons(fin->fin_mtu);
646
647		} else if (ifp != NULL) {
648			icmp->icmp_nextmtu = htons(GETIFMTU_4(ifp));
649
650		} else {	/* make up a number... */
651			icmp->icmp_nextmtu = htons(fin->fin_plen - 20);
652		}
653	}
654#endif
655
656	bcopy((char *)fin->fin_ip, (char *)ip2, ohlen);
657
658#ifdef USE_INET6
659	ip6 = (ip6_t *)ip;
660	if (fin->fin_v == 6) {
661		ip6->ip6_flow = ((ip6_t *)fin->fin_ip)->ip6_flow;
662		ip6->ip6_plen = htons(iclen - hlen);
663		ip6->ip6_nxt = IPPROTO_ICMPV6;
664		ip6->ip6_hlim = 0;
665		ip6->ip6_src = dst6.in6;
666		ip6->ip6_dst = fin->fin_src6.in6;
667		if (xtra > 0)
668			bcopy((char *)fin->fin_ip + ohlen,
669			      (char *)&icmp->icmp_ip + ohlen, xtra);
670		icmp->icmp_cksum = in6_cksum(m, IPPROTO_ICMPV6,
671					     sizeof(*ip6), iclen - hlen);
672	} else
673#endif
674	{
675		ip->ip_p = IPPROTO_ICMP;
676		ip->ip_src.s_addr = dst4.s_addr;
677		ip->ip_dst.s_addr = fin->fin_saddr;
678
679		if (xtra > 0)
680			bcopy((char *)fin->fin_ip + ohlen,
681			      (char *)&icmp->icmp_ip + ohlen, xtra);
682		icmp->icmp_cksum = ipf_cksum((u_short *)icmp,
683					     sizeof(*icmp) + 8);
684		ip->ip_len = htons(iclen);
685		ip->ip_p = IPPROTO_ICMP;
686	}
687	err = ipf_send_ip(fin, m);
688	return err;
689}
690
691
692
693
694/*
695 * m0 - pointer to mbuf where the IP packet starts
696 * mpp - pointer to the mbuf pointer that is the start of the mbuf chain
697 */
698int
699ipf_fastroute(m0, mpp, fin, fdp)
700	mb_t *m0, **mpp;
701	fr_info_t *fin;
702	frdest_t *fdp;
703{
704	register struct ip *ip, *mhip;
705	register struct mbuf *m = *mpp;
706	register struct route *ro;
707	int len, off, error = 0, hlen, code;
708	struct ifnet *ifp, *sifp;
709	struct sockaddr_in *dst;
710	struct route iproute;
711	u_short ip_off;
712	frdest_t node;
713	frentry_t *fr;
714
715	ro = NULL;
716
717#ifdef M_WRITABLE
718	/*
719	* HOT FIX/KLUDGE:
720	*
721	* If the mbuf we're about to send is not writable (because of
722	* a cluster reference, for example) we'll need to make a copy
723	* of it since this routine modifies the contents.
724	*
725	* If you have non-crappy network hardware that can transmit data
726	* from the mbuf, rather than making a copy, this is gonna be a
727	* problem.
728	*/
729	if (M_WRITABLE(m) == 0) {
730		m0 = m_dup(m, M_DONTWAIT);
731		if (m0 != NULL) {
732			FREE_MB_T(m);
733			m = m0;
734			*mpp = m;
735		} else {
736			error = ENOBUFS;
737			FREE_MB_T(m);
738			goto done;
739		}
740	}
741#endif
742
743#ifdef USE_INET6
744	if (fin->fin_v == 6) {
745		/*
746		 * currently "to <if>" and "to <if>:ip#" are not supported
747		 * for IPv6
748		 */
749		return ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
750	}
751#endif
752
753	hlen = fin->fin_hlen;
754	ip = mtod(m0, struct ip *);
755	ifp = NULL;
756
757	/*
758	 * Route packet.
759	 */
760	ro = &iproute;
761	bzero(ro, sizeof (*ro));
762	dst = (struct sockaddr_in *)&ro->ro_dst;
763	dst->sin_family = AF_INET;
764	dst->sin_addr = ip->ip_dst;
765
766	fr = fin->fin_fr;
767	if ((fr != NULL) && !(fr->fr_flags & FR_KEEPSTATE) && (fdp != NULL) &&
768	    (fdp->fd_type == FRD_DSTLIST)) {
769		if (ipf_dstlist_select_node(fin, fdp->fd_ptr, NULL, &node) == 0)
770			fdp = &node;
771	}
772
773	if (fdp != NULL)
774		ifp = fdp->fd_ptr;
775	else
776		ifp = fin->fin_ifp;
777
778	if ((ifp == NULL) && ((fr == NULL) || !(fr->fr_flags & FR_FASTROUTE))) {
779		error = -2;
780		goto bad;
781	}
782
783	if ((fdp != NULL) && (fdp->fd_ip.s_addr != 0))
784		dst->sin_addr = fdp->fd_ip;
785
786	dst->sin_len = sizeof(*dst);
787	in_rtalloc(ro, M_GETFIB(m0));
788
789	if ((ifp == NULL) && (ro->ro_rt != NULL))
790		ifp = ro->ro_rt->rt_ifp;
791
792	if ((ro->ro_rt == NULL) || (ifp == NULL)) {
793		if (in_localaddr(ip->ip_dst))
794			error = EHOSTUNREACH;
795		else
796			error = ENETUNREACH;
797		goto bad;
798	}
799	if (ro->ro_rt->rt_flags & RTF_GATEWAY)
800		dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway;
801	if (ro->ro_rt)
802		counter_u64_add(ro->ro_rt->rt_pksent, 1);
803
804	/*
805	 * For input packets which are being "fastrouted", they won't
806	 * go back through output filtering and miss their chance to get
807	 * NAT'd and counted.  Duplicated packets aren't considered to be
808	 * part of the normal packet stream, so do not NAT them or pass
809	 * them through stateful checking, etc.
810	 */
811	if ((fdp != &fr->fr_dif) && (fin->fin_out == 0)) {
812		sifp = fin->fin_ifp;
813		fin->fin_ifp = ifp;
814		fin->fin_out = 1;
815		(void) ipf_acctpkt(fin, NULL);
816		fin->fin_fr = NULL;
817		if (!fr || !(fr->fr_flags & FR_RETMASK)) {
818			u_32_t pass;
819
820			(void) ipf_state_check(fin, &pass);
821		}
822
823		switch (ipf_nat_checkout(fin, NULL))
824		{
825		case 0 :
826			break;
827		case 1 :
828			ip->ip_sum = 0;
829			break;
830		case -1 :
831			error = -1;
832			goto bad;
833			break;
834		}
835
836		fin->fin_ifp = sifp;
837		fin->fin_out = 0;
838	} else
839		ip->ip_sum = 0;
840	/*
841	 * If small enough for interface, can just send directly.
842	 */
843	if (ntohs(ip->ip_len) <= ifp->if_mtu) {
844		if (!ip->ip_sum)
845			ip->ip_sum = in_cksum(m, hlen);
846		error = (*ifp->if_output)(ifp, m, (struct sockaddr *)dst,
847			    ro
848			);
849		goto done;
850	}
851	/*
852	 * Too large for interface; fragment if possible.
853	 * Must be able to put at least 8 bytes per fragment.
854	 */
855	ip_off = ntohs(ip->ip_off);
856	if (ip_off & IP_DF) {
857		error = EMSGSIZE;
858		goto bad;
859	}
860	len = (ifp->if_mtu - hlen) &~ 7;
861	if (len < 8) {
862		error = EMSGSIZE;
863		goto bad;
864	}
865
866    {
867	int mhlen, firstlen = len;
868	struct mbuf **mnext = &m->m_act;
869
870	/*
871	 * Loop through length of segment after first fragment,
872	 * make new header and copy data of each part and link onto chain.
873	 */
874	m0 = m;
875	mhlen = sizeof (struct ip);
876	for (off = hlen + len; off < ntohs(ip->ip_len); off += len) {
877#ifdef MGETHDR
878		MGETHDR(m, M_DONTWAIT, MT_HEADER);
879#else
880		MGET(m, M_DONTWAIT, MT_HEADER);
881#endif
882		if (m == NULL) {
883			m = m0;
884			error = ENOBUFS;
885			goto bad;
886		}
887		m->m_data += max_linkhdr;
888		mhip = mtod(m, struct ip *);
889		bcopy((char *)ip, (char *)mhip, sizeof(*ip));
890		if (hlen > sizeof (struct ip)) {
891			mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
892			IP_HL_A(mhip, mhlen >> 2);
893		}
894		m->m_len = mhlen;
895		mhip->ip_off = ((off - hlen) >> 3) + ip_off;
896		if (off + len >= ntohs(ip->ip_len))
897			len = ntohs(ip->ip_len) - off;
898		else
899			mhip->ip_off |= IP_MF;
900		mhip->ip_len = htons((u_short)(len + mhlen));
901		*mnext = m;
902		m->m_next = m_copy(m0, off, len);
903		if (m->m_next == 0) {
904			error = ENOBUFS;	/* ??? */
905			goto sendorfree;
906		}
907		m->m_pkthdr.len = mhlen + len;
908		m->m_pkthdr.rcvif = NULL;
909		mhip->ip_off = htons((u_short)mhip->ip_off);
910		mhip->ip_sum = 0;
911		mhip->ip_sum = in_cksum(m, mhlen);
912		mnext = &m->m_act;
913	}
914	/*
915	 * Update first fragment by trimming what's been copied out
916	 * and updating header, then send each fragment (in order).
917	 */
918	m_adj(m0, hlen + firstlen - ip->ip_len);
919	ip->ip_len = htons((u_short)(hlen + firstlen));
920	ip->ip_off = htons((u_short)IP_MF);
921	ip->ip_sum = 0;
922	ip->ip_sum = in_cksum(m0, hlen);
923sendorfree:
924	for (m = m0; m; m = m0) {
925		m0 = m->m_act;
926		m->m_act = 0;
927		if (error == 0)
928			error = (*ifp->if_output)(ifp, m,
929			    (struct sockaddr *)dst,
930			    ro
931			    );
932		else
933			FREE_MB_T(m);
934	}
935    }
936done:
937	if (!error)
938		ipfmain.ipf_frouteok[0]++;
939	else
940		ipfmain.ipf_frouteok[1]++;
941
942	if ((ro != NULL) && (ro->ro_rt != NULL)) {
943		RTFREE(ro->ro_rt);
944	}
945	return 0;
946bad:
947	if (error == EMSGSIZE) {
948		sifp = fin->fin_ifp;
949		code = fin->fin_icode;
950		fin->fin_icode = ICMP_UNREACH_NEEDFRAG;
951		fin->fin_ifp = ifp;
952		(void) ipf_send_icmp_err(ICMP_UNREACH, fin, 1);
953		fin->fin_ifp = sifp;
954		fin->fin_icode = code;
955	}
956	FREE_MB_T(m);
957	goto done;
958}
959
960
961int
962ipf_verifysrc(fin)
963	fr_info_t *fin;
964{
965	struct sockaddr_in *dst;
966	struct route iproute;
967
968	bzero((char *)&iproute, sizeof(iproute));
969	dst = (struct sockaddr_in *)&iproute.ro_dst;
970	dst->sin_len = sizeof(*dst);
971	dst->sin_family = AF_INET;
972	dst->sin_addr = fin->fin_src;
973	in_rtalloc(&iproute, 0);
974	if (iproute.ro_rt == NULL)
975		return 0;
976	return (fin->fin_ifp == iproute.ro_rt->rt_ifp);
977}
978
979
980/*
981 * return the first IP Address associated with an interface
982 */
983int
984ipf_ifpaddr(softc, v, atype, ifptr, inp, inpmask)
985	ipf_main_softc_t *softc;
986	int v, atype;
987	void *ifptr;
988	i6addr_t *inp, *inpmask;
989{
990#ifdef USE_INET6
991	struct in6_addr *inp6 = NULL;
992#endif
993	struct sockaddr *sock, *mask;
994	struct sockaddr_in *sin;
995	struct ifaddr *ifa;
996	struct ifnet *ifp;
997
998	if ((ifptr == NULL) || (ifptr == (void *)-1))
999		return -1;
1000
1001	sin = NULL;
1002	ifp = ifptr;
1003
1004	if (v == 4)
1005		inp->in4.s_addr = 0;
1006#ifdef USE_INET6
1007	else if (v == 6)
1008		bzero((char *)inp, sizeof(*inp));
1009#endif
1010	ifa = TAILQ_FIRST(&ifp->if_addrhead);
1011
1012	sock = ifa->ifa_addr;
1013	while (sock != NULL && ifa != NULL) {
1014		sin = (struct sockaddr_in *)sock;
1015		if ((v == 4) && (sin->sin_family == AF_INET))
1016			break;
1017#ifdef USE_INET6
1018		if ((v == 6) && (sin->sin_family == AF_INET6)) {
1019			inp6 = &((struct sockaddr_in6 *)sin)->sin6_addr;
1020			if (!IN6_IS_ADDR_LINKLOCAL(inp6) &&
1021			    !IN6_IS_ADDR_LOOPBACK(inp6))
1022				break;
1023		}
1024#endif
1025		ifa = TAILQ_NEXT(ifa, ifa_link);
1026		if (ifa != NULL)
1027			sock = ifa->ifa_addr;
1028	}
1029
1030	if (ifa == NULL || sin == NULL)
1031		return -1;
1032
1033	mask = ifa->ifa_netmask;
1034	if (atype == FRI_BROADCAST)
1035		sock = ifa->ifa_broadaddr;
1036	else if (atype == FRI_PEERADDR)
1037		sock = ifa->ifa_dstaddr;
1038
1039	if (sock == NULL)
1040		return -1;
1041
1042#ifdef USE_INET6
1043	if (v == 6) {
1044		return ipf_ifpfillv6addr(atype, (struct sockaddr_in6 *)sock,
1045					 (struct sockaddr_in6 *)mask,
1046					 inp, inpmask);
1047	}
1048#endif
1049	return ipf_ifpfillv4addr(atype, (struct sockaddr_in *)sock,
1050				 (struct sockaddr_in *)mask,
1051				 &inp->in4, &inpmask->in4);
1052}
1053
1054
1055u_32_t
1056ipf_newisn(fin)
1057	fr_info_t *fin;
1058{
1059	u_32_t newiss;
1060	newiss = arc4random();
1061	return newiss;
1062}
1063
1064
1065/* ------------------------------------------------------------------------ */
1066/* Function:    ipf_nextipid                                                */
1067/* Returns:     int - 0 == success, -1 == error (packet should be droppped) */
1068/* Parameters:  fin(I) - pointer to packet information                      */
1069/*                                                                          */
1070/* Returns the next IPv4 ID to use for this packet.                         */
1071/* ------------------------------------------------------------------------ */
1072u_short
1073ipf_nextipid(fin)
1074	fr_info_t *fin;
1075{
1076	u_short id;
1077
1078#ifndef	RANDOM_IP_ID
1079	MUTEX_ENTER(&ipfmain.ipf_rw);
1080	id = ipid++;
1081	MUTEX_EXIT(&ipfmain.ipf_rw);
1082#else
1083	id = ip_randomid();
1084#endif
1085
1086	return id;
1087}
1088
1089
1090INLINE int
1091ipf_checkv4sum(fin)
1092	fr_info_t *fin;
1093{
1094#ifdef CSUM_DATA_VALID
1095	int manual = 0;
1096	u_short sum;
1097	ip_t *ip;
1098	mb_t *m;
1099
1100	if ((fin->fin_flx & FI_NOCKSUM) != 0)
1101		return 0;
1102
1103	if ((fin->fin_flx & FI_SHORT) != 0)
1104		return 1;
1105
1106	if (fin->fin_cksum != FI_CK_NEEDED)
1107		return (fin->fin_cksum > FI_CK_NEEDED) ? 0 : -1;
1108
1109	m = fin->fin_m;
1110	if (m == NULL) {
1111		manual = 1;
1112		goto skipauto;
1113	}
1114	ip = fin->fin_ip;
1115
1116	if ((m->m_pkthdr.csum_flags & (CSUM_IP_CHECKED|CSUM_IP_VALID)) ==
1117	    CSUM_IP_CHECKED) {
1118		fin->fin_cksum = FI_CK_BAD;
1119		fin->fin_flx |= FI_BAD;
1120		return -1;
1121	}
1122	if (m->m_pkthdr.csum_flags & CSUM_DATA_VALID) {
1123		/* Depending on the driver, UDP may have zero checksum */
1124		if (fin->fin_p == IPPROTO_UDP && (fin->fin_flx &
1125		    (FI_FRAG|FI_SHORT|FI_BAD)) == 0) {
1126			udphdr_t *udp = fin->fin_dp;
1127			if (udp->uh_sum == 0) {
1128				/*
1129				 * we're good no matter what the hardware
1130				 * checksum flags and csum_data say (handling
1131				 * of csum_data for zero UDP checksum is not
1132				 * consistent across all drivers)
1133				 */
1134				fin->fin_cksum = 1;
1135				return 0;
1136			}
1137		}
1138
1139		if (m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR)
1140			sum = m->m_pkthdr.csum_data;
1141		else
1142			sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
1143					htonl(m->m_pkthdr.csum_data +
1144					fin->fin_dlen + fin->fin_p));
1145		sum ^= 0xffff;
1146		if (sum != 0) {
1147			fin->fin_cksum = FI_CK_BAD;
1148			fin->fin_flx |= FI_BAD;
1149		} else {
1150			fin->fin_cksum = FI_CK_SUMOK;
1151			return 0;
1152		}
1153	} else {
1154		if (m->m_pkthdr.csum_flags == CSUM_DELAY_DATA) {
1155			fin->fin_cksum = FI_CK_L4FULL;
1156			return 0;
1157		} else if (m->m_pkthdr.csum_flags == CSUM_TCP ||
1158			   m->m_pkthdr.csum_flags == CSUM_UDP) {
1159			fin->fin_cksum = FI_CK_L4PART;
1160			return 0;
1161		} else if (m->m_pkthdr.csum_flags == CSUM_IP) {
1162			fin->fin_cksum = FI_CK_L4PART;
1163			return 0;
1164		} else {
1165			manual = 1;
1166		}
1167	}
1168skipauto:
1169	if (manual != 0) {
1170		if (ipf_checkl4sum(fin) == -1) {
1171			fin->fin_flx |= FI_BAD;
1172			return -1;
1173		}
1174	}
1175#else
1176	if (ipf_checkl4sum(fin) == -1) {
1177		fin->fin_flx |= FI_BAD;
1178		return -1;
1179	}
1180#endif
1181	return 0;
1182}
1183
1184
1185#ifdef USE_INET6
1186INLINE int
1187ipf_checkv6sum(fin)
1188	fr_info_t *fin;
1189{
1190	if ((fin->fin_flx & FI_NOCKSUM) != 0)
1191		return 0;
1192
1193	if ((fin->fin_flx & FI_SHORT) != 0)
1194		return 1;
1195
1196	if (fin->fin_cksum != FI_CK_NEEDED)
1197		return (fin->fin_cksum > FI_CK_NEEDED) ? 0 : -1;
1198
1199	if (ipf_checkl4sum(fin) == -1) {
1200		fin->fin_flx |= FI_BAD;
1201		return -1;
1202	}
1203	return 0;
1204}
1205#endif /* USE_INET6 */
1206
1207
1208size_t
1209mbufchainlen(m0)
1210	struct mbuf *m0;
1211	{
1212	size_t len;
1213
1214	if ((m0->m_flags & M_PKTHDR) != 0) {
1215		len = m0->m_pkthdr.len;
1216	} else {
1217		struct mbuf *m;
1218
1219		for (m = m0, len = 0; m != NULL; m = m->m_next)
1220			len += m->m_len;
1221	}
1222	return len;
1223}
1224
1225
1226/* ------------------------------------------------------------------------ */
1227/* Function:    ipf_pullup                                                  */
1228/* Returns:     NULL == pullup failed, else pointer to protocol header      */
1229/* Parameters:  xmin(I)- pointer to buffer where data packet starts         */
1230/*              fin(I) - pointer to packet information                      */
1231/*              len(I) - number of bytes to pullup                          */
1232/*                                                                          */
1233/* Attempt to move at least len bytes (from the start of the buffer) into a */
1234/* single buffer for ease of access.  Operating system native functions are */
1235/* used to manage buffers - if necessary.  If the entire packet ends up in  */
1236/* a single buffer, set the FI_COALESCE flag even though ipf_coalesce() has */
1237/* not been called.  Both fin_ip and fin_dp are updated before exiting _IF_ */
1238/* and ONLY if the pullup succeeds.                                         */
1239/*                                                                          */
1240/* We assume that 'xmin' is a pointer to a buffer that is part of the chain */
1241/* of buffers that starts at *fin->fin_mp.                                  */
1242/* ------------------------------------------------------------------------ */
1243void *
1244ipf_pullup(xmin, fin, len)
1245	mb_t *xmin;
1246	fr_info_t *fin;
1247	int len;
1248{
1249	int dpoff, ipoff;
1250	mb_t *m = xmin;
1251	char *ip;
1252
1253	if (m == NULL)
1254		return NULL;
1255
1256	ip = (char *)fin->fin_ip;
1257	if ((fin->fin_flx & FI_COALESCE) != 0)
1258		return ip;
1259
1260	ipoff = fin->fin_ipoff;
1261	if (fin->fin_dp != NULL)
1262		dpoff = (char *)fin->fin_dp - (char *)ip;
1263	else
1264		dpoff = 0;
1265
1266	if (M_LEN(m) < len) {
1267		mb_t *n = *fin->fin_mp;
1268		/*
1269		 * Assume that M_PKTHDR is set and just work with what is left
1270		 * rather than check..
1271		 * Should not make any real difference, anyway.
1272		 */
1273		if (m != n) {
1274			/*
1275			 * Record the mbuf that points to the mbuf that we're
1276			 * about to go to work on so that we can update the
1277			 * m_next appropriately later.
1278			 */
1279			for (; n->m_next != m; n = n->m_next)
1280				;
1281		} else {
1282			n = NULL;
1283		}
1284
1285#ifdef MHLEN
1286		if (len > MHLEN)
1287#else
1288		if (len > MLEN)
1289#endif
1290		{
1291#ifdef HAVE_M_PULLDOWN
1292			if (m_pulldown(m, 0, len, NULL) == NULL)
1293				m = NULL;
1294#else
1295			FREE_MB_T(*fin->fin_mp);
1296			m = NULL;
1297			n = NULL;
1298#endif
1299		} else
1300		{
1301			m = m_pullup(m, len);
1302		}
1303		if (n != NULL)
1304			n->m_next = m;
1305		if (m == NULL) {
1306			/*
1307			 * When n is non-NULL, it indicates that m pointed to
1308			 * a sub-chain (tail) of the mbuf and that the head
1309			 * of this chain has not yet been free'd.
1310			 */
1311			if (n != NULL) {
1312				FREE_MB_T(*fin->fin_mp);
1313			}
1314
1315			*fin->fin_mp = NULL;
1316			fin->fin_m = NULL;
1317			return NULL;
1318		}
1319
1320		if (n == NULL)
1321			*fin->fin_mp = m;
1322
1323		while (M_LEN(m) == 0) {
1324			m = m->m_next;
1325		}
1326		fin->fin_m = m;
1327		ip = MTOD(m, char *) + ipoff;
1328
1329		fin->fin_ip = (ip_t *)ip;
1330		if (fin->fin_dp != NULL)
1331			fin->fin_dp = (char *)fin->fin_ip + dpoff;
1332		if (fin->fin_fraghdr != NULL)
1333			fin->fin_fraghdr = (char *)ip +
1334					   ((char *)fin->fin_fraghdr -
1335					    (char *)fin->fin_ip);
1336	}
1337
1338	if (len == fin->fin_plen)
1339		fin->fin_flx |= FI_COALESCE;
1340	return ip;
1341}
1342
1343
1344int
1345ipf_inject(fin, m)
1346	fr_info_t *fin;
1347	mb_t *m;
1348{
1349	int error = 0;
1350
1351	if (fin->fin_out == 0) {
1352		netisr_dispatch(NETISR_IP, m);
1353	} else {
1354		fin->fin_ip->ip_len = ntohs(fin->fin_ip->ip_len);
1355		fin->fin_ip->ip_off = ntohs(fin->fin_ip->ip_off);
1356		error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL);
1357	}
1358
1359	return error;
1360}
1361
1362int ipf_pfil_unhook(void) {
1363#if defined(NETBSD_PF) && (__FreeBSD_version >= 500011)
1364	struct pfil_head *ph_inet;
1365#  ifdef USE_INET6
1366	struct pfil_head *ph_inet6;
1367#  endif
1368#endif
1369
1370#ifdef NETBSD_PF
1371	ph_inet = pfil_head_get(PFIL_TYPE_AF, AF_INET);
1372	if (ph_inet != NULL)
1373		pfil_remove_hook((void *)ipf_check_wrapper, NULL,
1374		    PFIL_IN|PFIL_OUT|PFIL_WAITOK, ph_inet);
1375# ifdef USE_INET6
1376	ph_inet6 = pfil_head_get(PFIL_TYPE_AF, AF_INET6);
1377	if (ph_inet6 != NULL)
1378		pfil_remove_hook((void *)ipf_check_wrapper6, NULL,
1379		    PFIL_IN|PFIL_OUT|PFIL_WAITOK, ph_inet6);
1380# endif
1381#endif
1382
1383	return (0);
1384}
1385
1386int ipf_pfil_hook(void) {
1387#if defined(NETBSD_PF) && (__FreeBSD_version >= 500011)
1388	struct pfil_head *ph_inet;
1389#  ifdef USE_INET6
1390	struct pfil_head *ph_inet6;
1391#  endif
1392#endif
1393
1394# ifdef NETBSD_PF
1395	ph_inet = pfil_head_get(PFIL_TYPE_AF, AF_INET);
1396#    ifdef USE_INET6
1397	ph_inet6 = pfil_head_get(PFIL_TYPE_AF, AF_INET6);
1398#    endif
1399	if (ph_inet == NULL
1400#    ifdef USE_INET6
1401	    && ph_inet6 == NULL
1402#    endif
1403	   ) {
1404		return ENODEV;
1405	}
1406
1407	if (ph_inet != NULL)
1408		pfil_add_hook((void *)ipf_check_wrapper, NULL,
1409		    PFIL_IN|PFIL_OUT|PFIL_WAITOK, ph_inet);
1410#  ifdef USE_INET6
1411	if (ph_inet6 != NULL)
1412		pfil_add_hook((void *)ipf_check_wrapper6, NULL,
1413				      PFIL_IN|PFIL_OUT|PFIL_WAITOK, ph_inet6);
1414#  endif
1415# endif
1416	return (0);
1417}
1418
1419void
1420ipf_event_reg(void)
1421{
1422	ipf_arrivetag = EVENTHANDLER_REGISTER(ifnet_arrival_event, \
1423					       ipf_ifevent, &ipfmain, \
1424					       EVENTHANDLER_PRI_ANY);
1425	ipf_departtag = EVENTHANDLER_REGISTER(ifnet_departure_event, \
1426					       ipf_ifevent, &ipfmain, \
1427					       EVENTHANDLER_PRI_ANY);
1428	ipf_clonetag  = EVENTHANDLER_REGISTER(if_clone_event, ipf_ifevent, \
1429					       &ipfmain, EVENTHANDLER_PRI_ANY);
1430}
1431
1432void
1433ipf_event_dereg(void)
1434{
1435	if (ipf_arrivetag != NULL) {
1436		EVENTHANDLER_DEREGISTER(ifnet_arrival_event, ipf_arrivetag);
1437	}
1438	if (ipf_departtag != NULL) {
1439		EVENTHANDLER_DEREGISTER(ifnet_departure_event, ipf_departtag);
1440	}
1441	if (ipf_clonetag != NULL) {
1442		EVENTHANDLER_DEREGISTER(if_clone_event, ipf_clonetag);
1443	}
1444}
1445
1446
1447u_32_t
1448ipf_random()
1449{
1450	return arc4random();
1451}
1452
1453
1454u_int
1455ipf_pcksum(fin, hlen, sum)
1456	fr_info_t *fin;
1457	int hlen;
1458	u_int sum;
1459{
1460	struct mbuf *m;
1461	u_int sum2;
1462	int off;
1463
1464	m = fin->fin_m;
1465	off = (char *)fin->fin_dp - (char *)fin->fin_ip;
1466	m->m_data += hlen;
1467	m->m_len -= hlen;
1468	sum2 = in_cksum(fin->fin_m, fin->fin_plen - off);
1469	m->m_len += hlen;
1470	m->m_data -= hlen;
1471
1472	/*
1473	 * Both sum and sum2 are partial sums, so combine them together.
1474	 */
1475	sum += ~sum2 & 0xffff;
1476	while (sum > 0xffff)
1477		sum = (sum & 0xffff) + (sum >> 16);
1478	sum2 = ~sum & 0xffff;
1479	return sum2;
1480}
1481