ip_fil_freebsd.c revision 259128 
1/*	$FreeBSD: releng/10.0/sys/contrib/ipfilter/netinet/ip_fil_freebsd.c 259128 2013-12-09 13:44:07Z gjb $	*/
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# include <sys/mbuf.h>
37# include <sys/sockopt.h>
38#if !defined(__hpux)
39# include <sys/mbuf.h>
40#endif
41#include <sys/socket.h>
42# include <sys/selinfo.h>
43# include <netinet/tcp_var.h>
44
45#include <net/if.h>
46# include <net/if_var.h>
47#  include <net/netisr.h>
48#include <net/route.h>
49#include <netinet/in.h>
50#include <netinet/in_var.h>
51#include <netinet/in_systm.h>
52#include <netinet/ip.h>
53#include <netinet/ip_var.h>
54#include <netinet/tcp.h>
55#if defined(__osf__)
56# include <netinet/tcp_timer.h>
57#endif
58#include <netinet/udp.h>
59#include <netinet/tcpip.h>
60#include <netinet/ip_icmp.h>
61#include "netinet/ip_compat.h"
62#ifdef USE_INET6
63# include <netinet/icmp6.h>
64#endif
65#include "netinet/ip_fil.h"
66#include "netinet/ip_nat.h"
67#include "netinet/ip_frag.h"
68#include "netinet/ip_state.h"
69#include "netinet/ip_proxy.h"
70#include "netinet/ip_auth.h"
71#include "netinet/ip_sync.h"
72#include "netinet/ip_lookup.h"
73#include "netinet/ip_dstlist.h"
74#ifdef	IPFILTER_SCAN
75#include "netinet/ip_scan.h"
76#endif
77#include "netinet/ip_pool.h"
78# include <sys/malloc.h>
79#include <sys/kernel.h>
80#ifdef CSUM_DATA_VALID
81#include <machine/in_cksum.h>
82#endif
83extern	int	ip_optcopy __P((struct ip *, struct ip *));
84
85
86# ifdef IPFILTER_M_IPFILTER
87MALLOC_DEFINE(M_IPFILTER, "ipfilter", "IP Filter packet filter data structures");
88# endif
89
90
91static	u_short	ipid = 0;
92static	int	(*ipf_savep) __P((void *, ip_t *, int, void *, int, struct mbuf **));
93static	int	ipf_send_ip __P((fr_info_t *, mb_t *));
94static void	ipf_timer_func __P((void *arg));
95int		ipf_locks_done = 0;
96
97ipf_main_softc_t ipfmain;
98
99# include <sys/conf.h>
100# if defined(NETBSD_PF)
101#  include <net/pfil.h>
102# endif /* NETBSD_PF */
103/*
104 * We provide the ipf_checkp name just to minimize changes later.
105 */
106int (*ipf_checkp) __P((void *, ip_t *ip, int hlen, void *ifp, int out, mb_t **mp));
107
108
109static eventhandler_tag ipf_arrivetag, ipf_departtag, ipf_clonetag;
110
111static void ipf_ifevent(void *arg);
112
113static void ipf_ifevent(arg)
114	void *arg;
115{
116        ipf_sync(arg, NULL);
117}
118
119
120
121static int
122ipf_check_wrapper(void *arg, struct mbuf **mp, struct ifnet *ifp, int dir)
123{
124	struct ip *ip = mtod(*mp, struct ip *);
125	int rv;
126
127	/*
128	 * IPFilter expects evreything in network byte order
129	 */
130#if (__FreeBSD_version < 1000019)
131	ip->ip_len = htons(ip->ip_len);
132	ip->ip_off = htons(ip->ip_off);
133#endif
134	rv = ipf_check(&ipfmain, ip, ip->ip_hl << 2, ifp, (dir == PFIL_OUT),
135		       mp);
136#if (__FreeBSD_version < 1000019)
137	if ((rv == 0) && (*mp != NULL)) {
138		ip = mtod(*mp, struct ip *);
139		ip->ip_len = ntohs(ip->ip_len);
140		ip->ip_off = ntohs(ip->ip_off);
141	}
142#endif
143	return rv;
144}
145
146# ifdef USE_INET6
147#  include <netinet/ip6.h>
148
149static int
150ipf_check_wrapper6(void *arg, struct mbuf **mp, struct ifnet *ifp, int dir)
151{
152	return (ipf_check(&ipfmain, mtod(*mp, struct ip *),
153			  sizeof(struct ip6_hdr), ifp, (dir == PFIL_OUT), mp));
154}
155# endif
156#if	defined(IPFILTER_LKM)
157int ipf_identify(s)
158	char *s;
159{
160	if (strcmp(s, "ipl") == 0)
161		return 1;
162	return 0;
163}
164#endif /* IPFILTER_LKM */
165
166
167static void
168ipf_timer_func(arg)
169	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, CALLOUT_MPSAFE);
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
194int
195ipfattach(softc)
196	ipf_main_softc_t *softc;
197{
198#ifdef USE_SPL
199	int s;
200#endif
201
202	SPL_NET(s);
203	if (softc->ipf_running > 0) {
204		SPL_X(s);
205		return EBUSY;
206	}
207
208	if (ipf_init_all(softc) < 0) {
209		SPL_X(s);
210		return EIO;
211	}
212
213
214	if (ipf_checkp != ipf_check) {
215		ipf_savep = ipf_checkp;
216		ipf_checkp = ipf_check;
217	}
218
219	bzero((char *)ipfmain.ipf_selwait, sizeof(ipfmain.ipf_selwait));
220	softc->ipf_running = 1;
221
222	if (softc->ipf_control_forwarding & 1)
223		V_ipforwarding = 1;
224
225	ipid = 0;
226
227	SPL_X(s);
228#if 0
229	softc->ipf_slow_ch = timeout(ipf_timer_func, softc,
230				     (hz / IPF_HZ_DIVIDE) * IPF_HZ_MULT);
231#endif
232	callout_init(&softc->ipf_slow_ch, CALLOUT_MPSAFE);
233	callout_reset(&softc->ipf_slow_ch, (hz / IPF_HZ_DIVIDE) * IPF_HZ_MULT,
234		ipf_timer_func, softc);
235	return 0;
236}
237
238
239/*
240 * Disable the filter by removing the hooks from the IP input/output
241 * stream.
242 */
243int
244ipfdetach(softc)
245	ipf_main_softc_t *softc;
246{
247#ifdef USE_SPL
248	int s;
249#endif
250
251	if (softc->ipf_control_forwarding & 2)
252		V_ipforwarding = 0;
253
254	SPL_NET(s);
255
256#if 0
257	if (softc->ipf_slow_ch.callout != NULL)
258		untimeout(ipf_timer_func, softc, softc->ipf_slow_ch);
259	bzero(&softc->ipf_slow, sizeof(softc->ipf_slow));
260#endif
261	callout_drain(&softc->ipf_slow_ch);
262
263#ifndef NETBSD_PF
264	if (ipf_checkp != NULL)
265		ipf_checkp = ipf_savep;
266	ipf_savep = NULL;
267#endif
268
269	ipf_fini_all(softc);
270
271	softc->ipf_running = -2;
272
273	SPL_X(s);
274
275	return 0;
276}
277
278
279/*
280 * Filter ioctl interface.
281 */
282int
283ipfioctl(dev, cmd, data, mode
284, p)
285	struct thread *p;
286#    define	p_cred	td_ucred
287#    define	p_uid	td_ucred->cr_ruid
288	struct cdev *dev;
289	ioctlcmd_t cmd;
290	caddr_t data;
291	int mode;
292{
293	int error = 0, unit = 0;
294	SPL_INT(s);
295
296#if (BSD >= 199306)
297        if (securelevel_ge(p->p_cred, 3) && (mode & FWRITE))
298	{
299		ipfmain.ipf_interror = 130001;
300		return EPERM;
301	}
302#endif
303
304	unit = GET_MINOR(dev);
305	if ((IPL_LOGMAX < unit) || (unit < 0)) {
306		ipfmain.ipf_interror = 130002;
307		return ENXIO;
308	}
309
310	if (ipfmain.ipf_running <= 0) {
311		if (unit != IPL_LOGIPF && cmd != SIOCIPFINTERROR) {
312			ipfmain.ipf_interror = 130003;
313			return EIO;
314		}
315		if (cmd != SIOCIPFGETNEXT && cmd != SIOCIPFGET &&
316		    cmd != SIOCIPFSET && cmd != SIOCFRENB &&
317		    cmd != SIOCGETFS && cmd != SIOCGETFF &&
318		    cmd != SIOCIPFINTERROR) {
319			ipfmain.ipf_interror = 130004;
320			return EIO;
321		}
322	}
323
324	SPL_NET(s);
325
326	error = ipf_ioctlswitch(&ipfmain, unit, data, cmd, mode, p->p_uid, p);
327	if (error != -1) {
328		SPL_X(s);
329		return error;
330	}
331
332	SPL_X(s);
333
334	return error;
335}
336
337
338/*
339 * ipf_send_reset - this could conceivably be a call to tcp_respond(), but that
340 * requires a large amount of setting up and isn't any more efficient.
341 */
342int
343ipf_send_reset(fin)
344	fr_info_t *fin;
345{
346	struct tcphdr *tcp, *tcp2;
347	int tlen = 0, hlen;
348	struct mbuf *m;
349#ifdef USE_INET6
350	ip6_t *ip6;
351#endif
352	ip_t *ip;
353
354	tcp = fin->fin_dp;
355	if (tcp->th_flags & TH_RST)
356		return -1;		/* feedback loop */
357
358	if (ipf_checkl4sum(fin) == -1)
359		return -1;
360
361	tlen = fin->fin_dlen - (TCP_OFF(tcp) << 2) +
362			((tcp->th_flags & TH_SYN) ? 1 : 0) +
363			((tcp->th_flags & TH_FIN) ? 1 : 0);
364
365#ifdef USE_INET6
366	hlen = (fin->fin_v == 6) ? sizeof(ip6_t) : sizeof(ip_t);
367#else
368	hlen = sizeof(ip_t);
369#endif
370#ifdef MGETHDR
371	MGETHDR(m, M_DONTWAIT, MT_HEADER);
372#else
373	MGET(m, M_DONTWAIT, MT_HEADER);
374#endif
375	if (m == NULL)
376		return -1;
377	if (sizeof(*tcp2) + hlen > MLEN) {
378		MCLGET(m, M_DONTWAIT);
379		if ((m->m_flags & M_EXT) == 0) {
380			FREE_MB_T(m);
381			return -1;
382		}
383	}
384
385	m->m_len = sizeof(*tcp2) + hlen;
386#if (BSD >= 199103)
387	m->m_data += max_linkhdr;
388	m->m_pkthdr.len = m->m_len;
389	m->m_pkthdr.rcvif = (struct ifnet *)0;
390#endif
391	ip = mtod(m, struct ip *);
392	bzero((char *)ip, hlen);
393#ifdef USE_INET6
394	ip6 = (ip6_t *)ip;
395#endif
396	tcp2 = (struct tcphdr *)((char *)ip + hlen);
397	tcp2->th_sport = tcp->th_dport;
398	tcp2->th_dport = tcp->th_sport;
399
400	if (tcp->th_flags & TH_ACK) {
401		tcp2->th_seq = tcp->th_ack;
402		tcp2->th_flags = TH_RST;
403		tcp2->th_ack = 0;
404	} else {
405		tcp2->th_seq = 0;
406		tcp2->th_ack = ntohl(tcp->th_seq);
407		tcp2->th_ack += tlen;
408		tcp2->th_ack = htonl(tcp2->th_ack);
409		tcp2->th_flags = TH_RST|TH_ACK;
410	}
411	TCP_X2_A(tcp2, 0);
412	TCP_OFF_A(tcp2, sizeof(*tcp2) >> 2);
413	tcp2->th_win = tcp->th_win;
414	tcp2->th_sum = 0;
415	tcp2->th_urp = 0;
416
417#ifdef USE_INET6
418	if (fin->fin_v == 6) {
419		ip6->ip6_flow = ((ip6_t *)fin->fin_ip)->ip6_flow;
420		ip6->ip6_plen = htons(sizeof(struct tcphdr));
421		ip6->ip6_nxt = IPPROTO_TCP;
422		ip6->ip6_hlim = 0;
423		ip6->ip6_src = fin->fin_dst6.in6;
424		ip6->ip6_dst = fin->fin_src6.in6;
425		tcp2->th_sum = in6_cksum(m, IPPROTO_TCP,
426					 sizeof(*ip6), sizeof(*tcp2));
427		return ipf_send_ip(fin, m);
428	}
429#endif
430	ip->ip_p = IPPROTO_TCP;
431	ip->ip_len = htons(sizeof(struct tcphdr));
432	ip->ip_src.s_addr = fin->fin_daddr;
433	ip->ip_dst.s_addr = fin->fin_saddr;
434	tcp2->th_sum = in_cksum(m, hlen + sizeof(*tcp2));
435	ip->ip_len = htons(hlen + sizeof(*tcp2));
436	return ipf_send_ip(fin, m);
437}
438
439
440/*
441 * ip_len must be in network byte order when called.
442 */
443static int
444ipf_send_ip(fin, m)
445	fr_info_t *fin;
446	mb_t *m;
447{
448	fr_info_t fnew;
449	ip_t *ip, *oip;
450	int hlen;
451
452	ip = mtod(m, ip_t *);
453	bzero((char *)&fnew, sizeof(fnew));
454	fnew.fin_main_soft = fin->fin_main_soft;
455
456	IP_V_A(ip, fin->fin_v);
457	switch (fin->fin_v)
458	{
459	case 4 :
460		oip = fin->fin_ip;
461		hlen = sizeof(*oip);
462		fnew.fin_v = 4;
463		fnew.fin_p = ip->ip_p;
464		fnew.fin_plen = ntohs(ip->ip_len);
465		IP_HL_A(ip, sizeof(*oip) >> 2);
466		ip->ip_tos = oip->ip_tos;
467		ip->ip_id = fin->fin_ip->ip_id;
468#if defined(FreeBSD) && (__FreeBSD_version > 460000)
469		ip->ip_off = htons(path_mtu_discovery ? IP_DF : 0);
470#else
471		ip->ip_off = 0;
472#endif
473		ip->ip_ttl = V_ip_defttl;
474		ip->ip_sum = 0;
475		break;
476#ifdef USE_INET6
477	case 6 :
478	{
479		ip6_t *ip6 = (ip6_t *)ip;
480
481		ip6->ip6_vfc = 0x60;
482		ip6->ip6_hlim = IPDEFTTL;
483
484		hlen = sizeof(*ip6);
485		fnew.fin_p = ip6->ip6_nxt;
486		fnew.fin_v = 6;
487		fnew.fin_plen = ntohs(ip6->ip6_plen) + hlen;
488		break;
489	}
490#endif
491	default :
492		return EINVAL;
493	}
494#ifdef IPSEC
495	m->m_pkthdr.rcvif = NULL;
496#endif
497
498	fnew.fin_ifp = fin->fin_ifp;
499	fnew.fin_flx = FI_NOCKSUM;
500	fnew.fin_m = m;
501	fnew.fin_ip = ip;
502	fnew.fin_mp = &m;
503	fnew.fin_hlen = hlen;
504	fnew.fin_dp = (char *)ip + hlen;
505	(void) ipf_makefrip(hlen, ip, &fnew);
506
507	return ipf_fastroute(m, &m, &fnew, NULL);
508}
509
510
511int
512ipf_send_icmp_err(type, fin, dst)
513	int type;
514	fr_info_t *fin;
515	int dst;
516{
517	int err, hlen, xtra, iclen, ohlen, avail, code;
518	struct in_addr dst4;
519	struct icmp *icmp;
520	struct mbuf *m;
521	i6addr_t dst6;
522	void *ifp;
523#ifdef USE_INET6
524	ip6_t *ip6;
525#endif
526	ip_t *ip, *ip2;
527
528	if ((type < 0) || (type >= ICMP_MAXTYPE))
529		return -1;
530
531	code = fin->fin_icode;
532#ifdef USE_INET6
533#if 0
534	/* XXX Fix an off by one error: s/>/>=/
535	 was:
536	 if ((code < 0) || (code > sizeof(icmptoicmp6unreach)/sizeof(int)))
537	 Fix obtained from NetBSD ip_fil_netbsd.c r1.4: */
538#endif
539	if ((code < 0) || (code >= sizeof(icmptoicmp6unreach)/sizeof(int)))
540		return -1;
541#endif
542
543	if (ipf_checkl4sum(fin) == -1)
544		return -1;
545#ifdef MGETHDR
546	MGETHDR(m, M_DONTWAIT, MT_HEADER);
547#else
548	MGET(m, M_DONTWAIT, MT_HEADER);
549#endif
550	if (m == NULL)
551		return -1;
552	avail = MHLEN;
553
554	xtra = 0;
555	hlen = 0;
556	ohlen = 0;
557	dst4.s_addr = 0;
558	ifp = fin->fin_ifp;
559	if (fin->fin_v == 4) {
560		if ((fin->fin_p == IPPROTO_ICMP) && !(fin->fin_flx & FI_SHORT))
561			switch (ntohs(fin->fin_data[0]) >> 8)
562			{
563			case ICMP_ECHO :
564			case ICMP_TSTAMP :
565			case ICMP_IREQ :
566			case ICMP_MASKREQ :
567				break;
568			default :
569				FREE_MB_T(m);
570				return 0;
571			}
572
573		if (dst == 0) {
574			if (ipf_ifpaddr(&ipfmain, 4, FRI_NORMAL, ifp,
575					&dst6, NULL) == -1) {
576				FREE_MB_T(m);
577				return -1;
578			}
579			dst4 = dst6.in4;
580		} else
581			dst4.s_addr = fin->fin_daddr;
582
583		hlen = sizeof(ip_t);
584		ohlen = fin->fin_hlen;
585		iclen = hlen + offsetof(struct icmp, icmp_ip) + ohlen;
586		if (fin->fin_hlen < fin->fin_plen)
587			xtra = MIN(fin->fin_dlen, 8);
588		else
589			xtra = 0;
590	}
591
592#ifdef USE_INET6
593	else if (fin->fin_v == 6) {
594		hlen = sizeof(ip6_t);
595		ohlen = sizeof(ip6_t);
596		iclen = hlen + offsetof(struct icmp, icmp_ip) + ohlen;
597		type = icmptoicmp6types[type];
598		if (type == ICMP6_DST_UNREACH)
599			code = icmptoicmp6unreach[code];
600
601		if (iclen + max_linkhdr + fin->fin_plen > avail) {
602			MCLGET(m, M_DONTWAIT);
603			if ((m->m_flags & M_EXT) == 0) {
604				FREE_MB_T(m);
605				return -1;
606			}
607			avail = MCLBYTES;
608		}
609		xtra = MIN(fin->fin_plen, avail - iclen - max_linkhdr);
610		xtra = MIN(xtra, IPV6_MMTU - iclen);
611		if (dst == 0) {
612			if (ipf_ifpaddr(&ipfmain, 6, FRI_NORMAL, ifp,
613					&dst6, NULL) == -1) {
614				FREE_MB_T(m);
615				return -1;
616			}
617		} else
618			dst6 = fin->fin_dst6;
619	}
620#endif
621	else {
622		FREE_MB_T(m);
623		return -1;
624	}
625
626	avail -= (max_linkhdr + iclen);
627	if (avail < 0) {
628		FREE_MB_T(m);
629		return -1;
630	}
631	if (xtra > avail)
632		xtra = avail;
633	iclen += xtra;
634	m->m_data += max_linkhdr;
635	m->m_pkthdr.rcvif = (struct ifnet *)0;
636	m->m_pkthdr.len = iclen;
637	m->m_len = iclen;
638	ip = mtod(m, ip_t *);
639	icmp = (struct icmp *)((char *)ip + hlen);
640	ip2 = (ip_t *)&icmp->icmp_ip;
641
642	icmp->icmp_type = type;
643	icmp->icmp_code = fin->fin_icode;
644	icmp->icmp_cksum = 0;
645#ifdef icmp_nextmtu
646	if (type == ICMP_UNREACH && fin->fin_icode == ICMP_UNREACH_NEEDFRAG) {
647		if (fin->fin_mtu != 0) {
648			icmp->icmp_nextmtu = htons(fin->fin_mtu);
649
650		} else if (ifp != NULL) {
651			icmp->icmp_nextmtu = htons(GETIFMTU_4(ifp));
652
653		} else {	/* make up a number... */
654			icmp->icmp_nextmtu = htons(fin->fin_plen - 20);
655		}
656	}
657#endif
658
659	bcopy((char *)fin->fin_ip, (char *)ip2, ohlen);
660
661#ifdef USE_INET6
662	ip6 = (ip6_t *)ip;
663	if (fin->fin_v == 6) {
664		ip6->ip6_flow = ((ip6_t *)fin->fin_ip)->ip6_flow;
665		ip6->ip6_plen = htons(iclen - hlen);
666		ip6->ip6_nxt = IPPROTO_ICMPV6;
667		ip6->ip6_hlim = 0;
668		ip6->ip6_src = dst6.in6;
669		ip6->ip6_dst = fin->fin_src6.in6;
670		if (xtra > 0)
671			bcopy((char *)fin->fin_ip + ohlen,
672			      (char *)&icmp->icmp_ip + ohlen, xtra);
673		icmp->icmp_cksum = in6_cksum(m, IPPROTO_ICMPV6,
674					     sizeof(*ip6), iclen - hlen);
675	} else
676#endif
677	{
678		ip->ip_p = IPPROTO_ICMP;
679		ip->ip_src.s_addr = dst4.s_addr;
680		ip->ip_dst.s_addr = fin->fin_saddr;
681
682		if (xtra > 0)
683			bcopy((char *)fin->fin_ip + ohlen,
684			      (char *)&icmp->icmp_ip + ohlen, xtra);
685		icmp->icmp_cksum = ipf_cksum((u_short *)icmp,
686					     sizeof(*icmp) + 8);
687		ip->ip_len = htons(iclen);
688		ip->ip_p = IPPROTO_ICMP;
689	}
690	err = ipf_send_ip(fin, m);
691	return err;
692}
693
694
695
696
697/*
698 * m0 - pointer to mbuf where the IP packet starts
699 * mpp - pointer to the mbuf pointer that is the start of the mbuf chain
700 */
701int
702ipf_fastroute(m0, mpp, fin, fdp)
703	mb_t *m0, **mpp;
704	fr_info_t *fin;
705	frdest_t *fdp;
706{
707	register struct ip *ip, *mhip;
708	register struct mbuf *m = *mpp;
709	register struct route *ro;
710	int len, off, error = 0, hlen, code;
711	struct ifnet *ifp, *sifp;
712	struct sockaddr_in *dst;
713	struct route iproute;
714	u_short ip_off;
715	frdest_t node;
716	frentry_t *fr;
717
718	ro = NULL;
719
720#ifdef M_WRITABLE
721	/*
722	* HOT FIX/KLUDGE:
723	*
724	* If the mbuf we're about to send is not writable (because of
725	* a cluster reference, for example) we'll need to make a copy
726	* of it since this routine modifies the contents.
727	*
728	* If you have non-crappy network hardware that can transmit data
729	* from the mbuf, rather than making a copy, this is gonna be a
730	* problem.
731	*/
732	if (M_WRITABLE(m) == 0) {
733		m0 = m_dup(m, M_DONTWAIT);
734		if (m0 != 0) {
735			FREE_MB_T(m);
736			m = m0;
737			*mpp = m;
738		} else {
739			error = ENOBUFS;
740			FREE_MB_T(m);
741			goto done;
742		}
743	}
744#endif
745
746#ifdef USE_INET6
747	if (fin->fin_v == 6) {
748		/*
749		 * currently "to <if>" and "to <if>:ip#" are not supported
750		 * for IPv6
751		 */
752		return ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
753	}
754#endif
755
756	hlen = fin->fin_hlen;
757	ip = mtod(m0, struct ip *);
758	ifp = NULL;
759
760	/*
761	 * Route packet.
762	 */
763	ro = &iproute;
764	bzero(ro, sizeof (*ro));
765	dst = (struct sockaddr_in *)&ro->ro_dst;
766	dst->sin_family = AF_INET;
767	dst->sin_addr = ip->ip_dst;
768
769	fr = fin->fin_fr;
770	if ((fr != NULL) && !(fr->fr_flags & FR_KEEPSTATE) && (fdp != NULL) &&
771	    (fdp->fd_type == FRD_DSTLIST)) {
772		if (ipf_dstlist_select_node(fin, fdp->fd_ptr, NULL, &node) == 0)
773			fdp = &node;
774	}
775
776	if (fdp != NULL)
777		ifp = fdp->fd_ptr;
778	else
779		ifp = fin->fin_ifp;
780
781	if ((ifp == NULL) && ((fr == NULL) || !(fr->fr_flags & FR_FASTROUTE))) {
782		error = -2;
783		goto bad;
784	}
785
786	if ((fdp != NULL) && (fdp->fd_ip.s_addr != 0))
787		dst->sin_addr = fdp->fd_ip;
788
789	dst->sin_len = sizeof(*dst);
790	in_rtalloc(ro, 0);
791
792	if ((ifp == NULL) && (ro->ro_rt != NULL))
793		ifp = ro->ro_rt->rt_ifp;
794
795	if ((ro->ro_rt == NULL) || (ifp == NULL)) {
796		if (in_localaddr(ip->ip_dst))
797			error = EHOSTUNREACH;
798		else
799			error = ENETUNREACH;
800		goto bad;
801	}
802	if (ro->ro_rt->rt_flags & RTF_GATEWAY)
803		dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway;
804	if (ro->ro_rt)
805		ro->ro_rt->rt_use++;
806
807	/*
808	 * For input packets which are being "fastrouted", they won't
809	 * go back through output filtering and miss their chance to get
810	 * NAT'd and counted.  Duplicated packets aren't considered to be
811	 * part of the normal packet stream, so do not NAT them or pass
812	 * them through stateful checking, etc.
813	 */
814	if ((fdp != &fr->fr_dif) && (fin->fin_out == 0)) {
815		sifp = fin->fin_ifp;
816		fin->fin_ifp = ifp;
817		fin->fin_out = 1;
818		(void) ipf_acctpkt(fin, NULL);
819		fin->fin_fr = NULL;
820		if (!fr || !(fr->fr_flags & FR_RETMASK)) {
821			u_32_t pass;
822
823			(void) ipf_state_check(fin, &pass);
824		}
825
826		switch (ipf_nat_checkout(fin, NULL))
827		{
828		case 0 :
829			break;
830		case 1 :
831			ip->ip_sum = 0;
832			break;
833		case -1 :
834			error = -1;
835			goto bad;
836			break;
837		}
838
839		fin->fin_ifp = sifp;
840		fin->fin_out = 0;
841	} else
842		ip->ip_sum = 0;
843	/*
844	 * If small enough for interface, can just send directly.
845	 */
846	if (ntohs(ip->ip_len) <= ifp->if_mtu) {
847		if (!ip->ip_sum)
848			ip->ip_sum = in_cksum(m, hlen);
849		error = (*ifp->if_output)(ifp, m, (struct sockaddr *)dst,
850			    ro
851			);
852		goto done;
853	}
854	/*
855	 * Too large for interface; fragment if possible.
856	 * Must be able to put at least 8 bytes per fragment.
857	 */
858	ip_off = ntohs(ip->ip_off);
859	if (ip_off & IP_DF) {
860		error = EMSGSIZE;
861		goto bad;
862	}
863	len = (ifp->if_mtu - hlen) &~ 7;
864	if (len < 8) {
865		error = EMSGSIZE;
866		goto bad;
867	}
868
869    {
870	int mhlen, firstlen = len;
871	struct mbuf **mnext = &m->m_act;
872
873	/*
874	 * Loop through length of segment after first fragment,
875	 * make new header and copy data of each part and link onto chain.
876	 */
877	m0 = m;
878	mhlen = sizeof (struct ip);
879	for (off = hlen + len; off < ntohs(ip->ip_len); off += len) {
880#ifdef MGETHDR
881		MGETHDR(m, M_DONTWAIT, MT_HEADER);
882#else
883		MGET(m, M_DONTWAIT, MT_HEADER);
884#endif
885		if (m == 0) {
886			m = m0;
887			error = ENOBUFS;
888			goto bad;
889		}
890		m->m_data += max_linkhdr;
891		mhip = mtod(m, struct ip *);
892		bcopy((char *)ip, (char *)mhip, sizeof(*ip));
893		if (hlen > sizeof (struct ip)) {
894			mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
895			IP_HL_A(mhip, mhlen >> 2);
896		}
897		m->m_len = mhlen;
898		mhip->ip_off = ((off - hlen) >> 3) + ip_off;
899		if (off + len >= ntohs(ip->ip_len))
900			len = ntohs(ip->ip_len) - off;
901		else
902			mhip->ip_off |= IP_MF;
903		mhip->ip_len = htons((u_short)(len + mhlen));
904		*mnext = m;
905		m->m_next = m_copy(m0, off, len);
906		if (m->m_next == 0) {
907			error = ENOBUFS;	/* ??? */
908			goto sendorfree;
909		}
910		m->m_pkthdr.len = mhlen + len;
911		m->m_pkthdr.rcvif = NULL;
912		mhip->ip_off = htons((u_short)mhip->ip_off);
913		mhip->ip_sum = 0;
914		mhip->ip_sum = in_cksum(m, mhlen);
915		mnext = &m->m_act;
916	}
917	/*
918	 * Update first fragment by trimming what's been copied out
919	 * and updating header, then send each fragment (in order).
920	 */
921	m_adj(m0, hlen + firstlen - ip->ip_len);
922	ip->ip_len = htons((u_short)(hlen + firstlen));
923	ip->ip_off = htons((u_short)IP_MF);
924	ip->ip_sum = 0;
925	ip->ip_sum = in_cksum(m0, hlen);
926sendorfree:
927	for (m = m0; m; m = m0) {
928		m0 = m->m_act;
929		m->m_act = 0;
930		if (error == 0)
931			error = (*ifp->if_output)(ifp, m,
932			    (struct sockaddr *)dst,
933			    ro
934			    );
935		else
936			FREE_MB_T(m);
937	}
938    }
939done:
940	if (!error)
941		ipfmain.ipf_frouteok[0]++;
942	else
943		ipfmain.ipf_frouteok[1]++;
944
945	if ((ro != NULL) && (ro->ro_rt != NULL)) {
946		RTFREE(ro->ro_rt);
947	}
948	return 0;
949bad:
950	if (error == EMSGSIZE) {
951		sifp = fin->fin_ifp;
952		code = fin->fin_icode;
953		fin->fin_icode = ICMP_UNREACH_NEEDFRAG;
954		fin->fin_ifp = ifp;
955		(void) ipf_send_icmp_err(ICMP_UNREACH, fin, 1);
956		fin->fin_ifp = sifp;
957		fin->fin_icode = code;
958	}
959	FREE_MB_T(m);
960	goto done;
961}
962
963
964int
965ipf_verifysrc(fin)
966	fr_info_t *fin;
967{
968	struct sockaddr_in *dst;
969	struct route iproute;
970
971	bzero((char *)&iproute, sizeof(iproute));
972	dst = (struct sockaddr_in *)&iproute.ro_dst;
973	dst->sin_len = sizeof(*dst);
974	dst->sin_family = AF_INET;
975	dst->sin_addr = fin->fin_src;
976	in_rtalloc(&iproute, 0);
977	if (iproute.ro_rt == NULL)
978		return 0;
979	return (fin->fin_ifp == iproute.ro_rt->rt_ifp);
980}
981
982
983/*
984 * return the first IP Address associated with an interface
985 */
986int
987ipf_ifpaddr(softc, v, atype, ifptr, inp, inpmask)
988	ipf_main_softc_t *softc;
989	int v, atype;
990	void *ifptr;
991	i6addr_t *inp, *inpmask;
992{
993#ifdef USE_INET6
994	struct in6_addr *inp6 = NULL;
995#endif
996	struct sockaddr *sock, *mask;
997	struct sockaddr_in *sin;
998	struct ifaddr *ifa;
999	struct ifnet *ifp;
1000
1001	if ((ifptr == NULL) || (ifptr == (void *)-1))
1002		return -1;
1003
1004	sin = NULL;
1005	ifp = ifptr;
1006
1007	if (v == 4)
1008		inp->in4.s_addr = 0;
1009#ifdef USE_INET6
1010	else if (v == 6)
1011		bzero((char *)inp, sizeof(*inp));
1012#endif
1013	ifa = TAILQ_FIRST(&ifp->if_addrhead);
1014
1015	sock = ifa->ifa_addr;
1016	while (sock != NULL && ifa != NULL) {
1017		sin = (struct sockaddr_in *)sock;
1018		if ((v == 4) && (sin->sin_family == AF_INET))
1019			break;
1020#ifdef USE_INET6
1021		if ((v == 6) && (sin->sin_family == AF_INET6)) {
1022			inp6 = &((struct sockaddr_in6 *)sin)->sin6_addr;
1023			if (!IN6_IS_ADDR_LINKLOCAL(inp6) &&
1024			    !IN6_IS_ADDR_LOOPBACK(inp6))
1025				break;
1026		}
1027#endif
1028		ifa = TAILQ_NEXT(ifa, ifa_link);
1029		if (ifa != NULL)
1030			sock = ifa->ifa_addr;
1031	}
1032
1033	if (ifa == NULL || sin == NULL)
1034		return -1;
1035
1036	mask = ifa->ifa_netmask;
1037	if (atype == FRI_BROADCAST)
1038		sock = ifa->ifa_broadaddr;
1039	else if (atype == FRI_PEERADDR)
1040		sock = ifa->ifa_dstaddr;
1041
1042	if (sock == NULL)
1043		return -1;
1044
1045#ifdef USE_INET6
1046	if (v == 6) {
1047		return ipf_ifpfillv6addr(atype, (struct sockaddr_in6 *)sock,
1048					 (struct sockaddr_in6 *)mask,
1049					 inp, inpmask);
1050	}
1051#endif
1052	return ipf_ifpfillv4addr(atype, (struct sockaddr_in *)sock,
1053				 (struct sockaddr_in *)mask,
1054				 &inp->in4, &inpmask->in4);
1055}
1056
1057
1058u_32_t
1059ipf_newisn(fin)
1060	fr_info_t *fin;
1061{
1062	u_32_t newiss;
1063	newiss = arc4random();
1064	return newiss;
1065}
1066
1067
1068/* ------------------------------------------------------------------------ */
1069/* Function:    ipf_nextipid                                                */
1070/* Returns:     int - 0 == success, -1 == error (packet should be droppped) */
1071/* Parameters:  fin(I) - pointer to packet information                      */
1072/*                                                                          */
1073/* Returns the next IPv4 ID to use for this packet.                         */
1074/* ------------------------------------------------------------------------ */
1075u_short
1076ipf_nextipid(fin)
1077	fr_info_t *fin;
1078{
1079	u_short id;
1080
1081#ifndef	RANDOM_IP_ID
1082	MUTEX_ENTER(&ipfmain.ipf_rw);
1083	id = ipid++;
1084	MUTEX_EXIT(&ipfmain.ipf_rw);
1085#else
1086	id = ip_randomid();
1087#endif
1088
1089	return id;
1090}
1091
1092
1093INLINE int
1094ipf_checkv4sum(fin)
1095	fr_info_t *fin;
1096{
1097#ifdef CSUM_DATA_VALID
1098	int manual = 0;
1099	u_short sum;
1100	ip_t *ip;
1101	mb_t *m;
1102
1103	if ((fin->fin_flx & FI_NOCKSUM) != 0)
1104		return 0;
1105
1106	if ((fin->fin_flx & FI_SHORT) != 0)
1107		return 1;
1108
1109	if (fin->fin_cksum != FI_CK_NEEDED)
1110		return (fin->fin_cksum > FI_CK_NEEDED) ? 0 : -1;
1111
1112	m = fin->fin_m;
1113	if (m == NULL) {
1114		manual = 1;
1115		goto skipauto;
1116	}
1117	ip = fin->fin_ip;
1118
1119	if ((m->m_pkthdr.csum_flags & (CSUM_IP_CHECKED|CSUM_IP_VALID)) ==
1120	    CSUM_IP_CHECKED) {
1121		fin->fin_cksum = FI_CK_BAD;
1122		fin->fin_flx |= FI_BAD;
1123		return -1;
1124	}
1125	if (m->m_pkthdr.csum_flags & CSUM_DATA_VALID) {
1126		if (m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR)
1127			sum = m->m_pkthdr.csum_data;
1128		else
1129			sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
1130					htonl(m->m_pkthdr.csum_data +
1131					fin->fin_dlen + fin->fin_p));
1132		sum ^= 0xffff;
1133		if (sum != 0) {
1134			fin->fin_cksum = FI_CK_BAD;
1135			fin->fin_flx |= FI_BAD;
1136		} else {
1137			fin->fin_cksum = FI_CK_SUMOK;
1138			return 0;
1139		}
1140	} else {
1141		if (m->m_pkthdr.csum_flags == CSUM_DELAY_DATA) {
1142			fin->fin_cksum = FI_CK_L4FULL;
1143			return 0;
1144		} else if (m->m_pkthdr.csum_flags == CSUM_TCP ||
1145			   m->m_pkthdr.csum_flags == CSUM_UDP) {
1146			fin->fin_cksum = FI_CK_L4PART;
1147			return 0;
1148		} else if (m->m_pkthdr.csum_flags == CSUM_IP) {
1149			fin->fin_cksum = FI_CK_L4PART;
1150			return 0;
1151		} else {
1152			manual = 1;
1153		}
1154	}
1155skipauto:
1156	if (manual != 0) {
1157		if (ipf_checkl4sum(fin) == -1) {
1158			fin->fin_flx |= FI_BAD;
1159			return -1;
1160		}
1161	}
1162#else
1163	if (ipf_checkl4sum(fin) == -1) {
1164		fin->fin_flx |= FI_BAD;
1165		return -1;
1166	}
1167#endif
1168	return 0;
1169}
1170
1171
1172#ifdef USE_INET6
1173INLINE int
1174ipf_checkv6sum(fin)
1175	fr_info_t *fin;
1176{
1177	if ((fin->fin_flx & FI_NOCKSUM) != 0)
1178		return 0;
1179
1180	if ((fin->fin_flx & FI_SHORT) != 0)
1181		return 1;
1182
1183	if (fin->fin_cksum != FI_CK_NEEDED)
1184		return (fin->fin_cksum > FI_CK_NEEDED) ? 0 : -1;
1185
1186	if (ipf_checkl4sum(fin) == -1) {
1187		fin->fin_flx |= FI_BAD;
1188		return -1;
1189	}
1190	return 0;
1191}
1192#endif /* USE_INET6 */
1193
1194
1195size_t
1196mbufchainlen(m0)
1197	struct mbuf *m0;
1198	{
1199	size_t len;
1200
1201	if ((m0->m_flags & M_PKTHDR) != 0) {
1202		len = m0->m_pkthdr.len;
1203	} else {
1204		struct mbuf *m;
1205
1206		for (m = m0, len = 0; m != NULL; m = m->m_next)
1207			len += m->m_len;
1208	}
1209	return len;
1210}
1211
1212
1213/* ------------------------------------------------------------------------ */
1214/* Function:    ipf_pullup                                                  */
1215/* Returns:     NULL == pullup failed, else pointer to protocol header      */
1216/* Parameters:  xmin(I)- pointer to buffer where data packet starts         */
1217/*              fin(I) - pointer to packet information                      */
1218/*              len(I) - number of bytes to pullup                          */
1219/*                                                                          */
1220/* Attempt to move at least len bytes (from the start of the buffer) into a */
1221/* single buffer for ease of access.  Operating system native functions are */
1222/* used to manage buffers - if necessary.  If the entire packet ends up in  */
1223/* a single buffer, set the FI_COALESCE flag even though ipf_coalesce() has */
1224/* not been called.  Both fin_ip and fin_dp are updated before exiting _IF_ */
1225/* and ONLY if the pullup succeeds.                                         */
1226/*                                                                          */
1227/* We assume that 'xmin' is a pointer to a buffer that is part of the chain */
1228/* of buffers that starts at *fin->fin_mp.                                  */
1229/* ------------------------------------------------------------------------ */
1230void *
1231ipf_pullup(xmin, fin, len)
1232	mb_t *xmin;
1233	fr_info_t *fin;
1234	int len;
1235{
1236	int dpoff, ipoff;
1237	mb_t *m = xmin;
1238	char *ip;
1239
1240	if (m == NULL)
1241		return NULL;
1242
1243	ip = (char *)fin->fin_ip;
1244	if ((fin->fin_flx & FI_COALESCE) != 0)
1245		return ip;
1246
1247	ipoff = fin->fin_ipoff;
1248	if (fin->fin_dp != NULL)
1249		dpoff = (char *)fin->fin_dp - (char *)ip;
1250	else
1251		dpoff = 0;
1252
1253	if (M_LEN(m) < len) {
1254		mb_t *n = *fin->fin_mp;
1255		/*
1256		 * Assume that M_PKTHDR is set and just work with what is left
1257		 * rather than check..
1258		 * Should not make any real difference, anyway.
1259		 */
1260		if (m != n) {
1261			/*
1262			 * Record the mbuf that points to the mbuf that we're
1263			 * about to go to work on so that we can update the
1264			 * m_next appropriately later.
1265			 */
1266			for (; n->m_next != m; n = n->m_next)
1267				;
1268		} else {
1269			n = NULL;
1270		}
1271
1272#ifdef MHLEN
1273		if (len > MHLEN)
1274#else
1275		if (len > MLEN)
1276#endif
1277		{
1278#ifdef HAVE_M_PULLDOWN
1279			if (m_pulldown(m, 0, len, NULL) == NULL)
1280				m = NULL;
1281#else
1282			FREE_MB_T(*fin->fin_mp);
1283			m = NULL;
1284			n = NULL;
1285#endif
1286		} else
1287		{
1288			m = m_pullup(m, len);
1289		}
1290		if (n != NULL)
1291			n->m_next = m;
1292		if (m == NULL) {
1293			/*
1294			 * When n is non-NULL, it indicates that m pointed to
1295			 * a sub-chain (tail) of the mbuf and that the head
1296			 * of this chain has not yet been free'd.
1297			 */
1298			if (n != NULL) {
1299				FREE_MB_T(*fin->fin_mp);
1300			}
1301
1302			*fin->fin_mp = NULL;
1303			fin->fin_m = NULL;
1304			return NULL;
1305		}
1306
1307		if (n == NULL)
1308			*fin->fin_mp = m;
1309
1310		while (M_LEN(m) == 0) {
1311			m = m->m_next;
1312		}
1313		fin->fin_m = m;
1314		ip = MTOD(m, char *) + ipoff;
1315
1316		fin->fin_ip = (ip_t *)ip;
1317		if (fin->fin_dp != NULL)
1318			fin->fin_dp = (char *)fin->fin_ip + dpoff;
1319		if (fin->fin_fraghdr != NULL)
1320			fin->fin_fraghdr = (char *)ip +
1321					   ((char *)fin->fin_fraghdr -
1322					    (char *)fin->fin_ip);
1323	}
1324
1325	if (len == fin->fin_plen)
1326		fin->fin_flx |= FI_COALESCE;
1327	return ip;
1328}
1329
1330
1331int
1332ipf_inject(fin, m)
1333	fr_info_t *fin;
1334	mb_t *m;
1335{
1336	int error = 0;
1337
1338	if (fin->fin_out == 0) {
1339		netisr_dispatch(NETISR_IP, m);
1340	} else {
1341		fin->fin_ip->ip_len = ntohs(fin->fin_ip->ip_len);
1342		fin->fin_ip->ip_off = ntohs(fin->fin_ip->ip_off);
1343		error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL);
1344	}
1345
1346	return error;
1347}
1348
1349int ipf_pfil_unhook(void) {
1350#if defined(NETBSD_PF) && (__FreeBSD_version >= 500011)
1351	struct pfil_head *ph_inet;
1352#  ifdef USE_INET6
1353	struct pfil_head *ph_inet6;
1354#  endif
1355#endif
1356
1357#ifdef NETBSD_PF
1358	ph_inet = pfil_head_get(PFIL_TYPE_AF, AF_INET);
1359	if (ph_inet != NULL)
1360		pfil_remove_hook((void *)ipf_check_wrapper, NULL,
1361		    PFIL_IN|PFIL_OUT|PFIL_WAITOK, ph_inet);
1362# ifdef USE_INET6
1363	ph_inet6 = pfil_head_get(PFIL_TYPE_AF, AF_INET6);
1364	if (ph_inet6 != NULL)
1365		pfil_remove_hook((void *)ipf_check_wrapper6, NULL,
1366		    PFIL_IN|PFIL_OUT|PFIL_WAITOK, ph_inet6);
1367# endif
1368#endif
1369
1370	return (0);
1371}
1372
1373int ipf_pfil_hook(void) {
1374#if defined(NETBSD_PF) && (__FreeBSD_version >= 500011)
1375	struct pfil_head *ph_inet;
1376#  ifdef USE_INET6
1377	struct pfil_head *ph_inet6;
1378#  endif
1379#endif
1380
1381# ifdef NETBSD_PF
1382	ph_inet = pfil_head_get(PFIL_TYPE_AF, AF_INET);
1383#    ifdef USE_INET6
1384	ph_inet6 = pfil_head_get(PFIL_TYPE_AF, AF_INET6);
1385#    endif
1386	if (ph_inet == NULL
1387#    ifdef USE_INET6
1388	    && ph_inet6 == NULL
1389#    endif
1390	   ) {
1391		return ENODEV;
1392	}
1393
1394	if (ph_inet != NULL)
1395		pfil_add_hook((void *)ipf_check_wrapper, NULL,
1396		    PFIL_IN|PFIL_OUT|PFIL_WAITOK, ph_inet);
1397#  ifdef USE_INET6
1398	if (ph_inet6 != NULL)
1399		pfil_add_hook((void *)ipf_check_wrapper6, NULL,
1400				      PFIL_IN|PFIL_OUT|PFIL_WAITOK, ph_inet6);
1401#  endif
1402# endif
1403	return (0);
1404}
1405
1406void
1407ipf_event_reg(void)
1408{
1409	ipf_arrivetag = EVENTHANDLER_REGISTER(ifnet_arrival_event, \
1410					       ipf_ifevent, &ipfmain, \
1411					       EVENTHANDLER_PRI_ANY);
1412	ipf_departtag = EVENTHANDLER_REGISTER(ifnet_departure_event, \
1413					       ipf_ifevent, &ipfmain, \
1414					       EVENTHANDLER_PRI_ANY);
1415	ipf_clonetag  = EVENTHANDLER_REGISTER(if_clone_event, ipf_ifevent, \
1416					       &ipfmain, EVENTHANDLER_PRI_ANY);
1417}
1418
1419void
1420ipf_event_dereg(void)
1421{
1422	if (ipf_arrivetag != NULL) {
1423		EVENTHANDLER_DEREGISTER(ifnet_arrival_event, ipf_arrivetag);
1424	}
1425	if (ipf_departtag != NULL) {
1426		EVENTHANDLER_DEREGISTER(ifnet_departure_event, ipf_departtag);
1427	}
1428	if (ipf_clonetag != NULL) {
1429		EVENTHANDLER_DEREGISTER(if_clone_event, ipf_clonetag);
1430	}
1431}
1432
1433
1434u_32_t
1435ipf_random()
1436{
1437	return arc4random();
1438}
1439
1440
1441u_int
1442ipf_pcksum(fin, hlen, sum)
1443	fr_info_t *fin;
1444	int hlen;
1445	u_int sum;
1446{
1447	struct mbuf *m;
1448	u_int sum2;
1449	int off;
1450
1451	m = fin->fin_m;
1452	off = (char *)fin->fin_dp - (char *)fin->fin_ip;
1453	m->m_data += hlen;
1454	m->m_len -= hlen;
1455	sum2 = in_cksum(fin->fin_m, fin->fin_plen - off);
1456	m->m_len += hlen;
1457	m->m_data -= hlen;
1458
1459	/*
1460	 * Both sum and sum2 are partial sums, so combine them together.
1461	 */
1462	sum += ~sum2 & 0xffff;
1463	while (sum > 0xffff)
1464		sum = (sum & 0xffff) + (sum >> 16);
1465	sum2 = ~sum & 0xffff;
1466	return sum2;
1467}
1468