ip_divert.c revision 157927
1/*-
2 * Copyright (c) 1982, 1986, 1988, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $FreeBSD: head/sys/netinet/ip_divert.c 157927 2006-04-21 09:25:40Z ps $
30 */
31
32#if !defined(KLD_MODULE)
33#include "opt_inet.h"
34#include "opt_ipfw.h"
35#include "opt_mac.h"
36#ifndef INET
37#error "IPDIVERT requires INET."
38#endif
39#ifndef IPFIREWALL
40#error "IPDIVERT requires IPFIREWALL"
41#endif
42#endif
43
44#include <sys/param.h>
45#include <sys/kernel.h>
46#include <sys/lock.h>
47#include <sys/malloc.h>
48#include <sys/mac.h>
49#include <sys/mbuf.h>
50#include <sys/module.h>
51#include <sys/kernel.h>
52#include <sys/proc.h>
53#include <sys/protosw.h>
54#include <sys/signalvar.h>
55#include <sys/socket.h>
56#include <sys/socketvar.h>
57#include <sys/sx.h>
58#include <sys/sysctl.h>
59#include <sys/systm.h>
60
61#include <vm/uma.h>
62
63#include <net/if.h>
64#include <net/route.h>
65
66#include <netinet/in.h>
67#include <netinet/in_pcb.h>
68#include <netinet/in_systm.h>
69#include <netinet/in_var.h>
70#include <netinet/ip.h>
71#include <netinet/ip_divert.h>
72#include <netinet/ip_var.h>
73#include <netinet/ip_fw.h>
74
75/*
76 * Divert sockets
77 */
78
79/*
80 * Allocate enough space to hold a full IP packet
81 */
82#define	DIVSNDQ		(65536 + 100)
83#define	DIVRCVQ		(65536 + 100)
84
85/*
86 * Divert sockets work in conjunction with ipfw, see the divert(4)
87 * manpage for features.
88 * Internally, packets selected by ipfw in ip_input() or ip_output(),
89 * and never diverted before, are passed to the input queue of the
90 * divert socket with a given 'divert_port' number (as specified in
91 * the matching ipfw rule), and they are tagged with a 16 bit cookie
92 * (representing the rule number of the matching ipfw rule), which
93 * is passed to process reading from the socket.
94 *
95 * Packets written to the divert socket are again tagged with a cookie
96 * (usually the same as above) and a destination address.
97 * If the destination address is INADDR_ANY then the packet is
98 * treated as outgoing and sent to ip_output(), otherwise it is
99 * treated as incoming and sent to ip_input().
100 * In both cases, the packet is tagged with the cookie.
101 *
102 * On reinjection, processing in ip_input() and ip_output()
103 * will be exactly the same as for the original packet, except that
104 * ipfw processing will start at the rule number after the one
105 * written in the cookie (so, tagging a packet with a cookie of 0
106 * will cause it to be effectively considered as a standard packet).
107 */
108
109/* Internal variables. */
110static struct inpcbhead divcb;
111static struct inpcbinfo divcbinfo;
112
113static u_long	div_sendspace = DIVSNDQ;	/* XXX sysctl ? */
114static u_long	div_recvspace = DIVRCVQ;	/* XXX sysctl ? */
115
116/*
117 * Initialize divert connection block queue.
118 */
119static void
120div_zone_change(void *tag)
121{
122
123	uma_zone_set_max(divcbinfo.ipi_zone, maxsockets);
124}
125
126void
127div_init(void)
128{
129	INP_INFO_LOCK_INIT(&divcbinfo, "div");
130	LIST_INIT(&divcb);
131	divcbinfo.listhead = &divcb;
132	/*
133	 * XXX We don't use the hash list for divert IP, but it's easier
134	 * to allocate a one entry hash list than it is to check all
135	 * over the place for hashbase == NULL.
136	 */
137	divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask);
138	divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask);
139	divcbinfo.ipi_zone = uma_zcreate("divcb", sizeof(struct inpcb),
140	    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
141	uma_zone_set_max(divcbinfo.ipi_zone, maxsockets);
142	EVENTHANDLER_REGISTER(maxsockets_change, div_zone_change,
143		NULL, EVENTHANDLER_PRI_ANY);
144}
145
146/*
147 * IPPROTO_DIVERT is not in the real IP protocol number space; this
148 * function should never be called.  Just in case, drop any packets.
149 */
150void
151div_input(struct mbuf *m, int off)
152{
153	ipstat.ips_noproto++;
154	m_freem(m);
155}
156
157/*
158 * Divert a packet by passing it up to the divert socket at port 'port'.
159 *
160 * Setup generic address and protocol structures for div_input routine,
161 * then pass them along with mbuf chain.
162 */
163static void
164divert_packet(struct mbuf *m, int incoming)
165{
166	struct ip *ip;
167	struct inpcb *inp;
168	struct socket *sa;
169	u_int16_t nport;
170	struct sockaddr_in divsrc;
171	struct m_tag *mtag;
172
173	mtag = m_tag_find(m, PACKET_TAG_DIVERT, NULL);
174	if (mtag == NULL) {
175		printf("%s: no divert tag\n", __func__);
176		m_freem(m);
177		return;
178	}
179	/* Assure header */
180	if (m->m_len < sizeof(struct ip) &&
181	    (m = m_pullup(m, sizeof(struct ip))) == 0)
182		return;
183	ip = mtod(m, struct ip *);
184
185	/* Delayed checksums are currently not compatible with divert. */
186	if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
187		ip->ip_len = ntohs(ip->ip_len);
188		in_delayed_cksum(m);
189		m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
190		ip->ip_len = htons(ip->ip_len);
191	}
192
193	/*
194	 * Record receive interface address, if any.
195	 * But only for incoming packets.
196	 */
197	bzero(&divsrc, sizeof(divsrc));
198	divsrc.sin_len = sizeof(divsrc);
199	divsrc.sin_family = AF_INET;
200	divsrc.sin_port = divert_cookie(mtag);	/* record matching rule */
201	if (incoming) {
202		struct ifaddr *ifa;
203
204		/* Sanity check */
205		M_ASSERTPKTHDR(m);
206
207		/* Find IP address for receive interface */
208		TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) {
209			if (ifa->ifa_addr == NULL)
210				continue;
211			if (ifa->ifa_addr->sa_family != AF_INET)
212				continue;
213			divsrc.sin_addr =
214			    ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr;
215			break;
216		}
217	}
218	/*
219	 * Record the incoming interface name whenever we have one.
220	 */
221	if (m->m_pkthdr.rcvif) {
222		/*
223		 * Hide the actual interface name in there in the
224		 * sin_zero array. XXX This needs to be moved to a
225		 * different sockaddr type for divert, e.g.
226		 * sockaddr_div with multiple fields like
227		 * sockaddr_dl. Presently we have only 7 bytes
228		 * but that will do for now as most interfaces
229		 * are 4 or less + 2 or less bytes for unit.
230		 * There is probably a faster way of doing this,
231		 * possibly taking it from the sockaddr_dl on the iface.
232		 * This solves the problem of a P2P link and a LAN interface
233		 * having the same address, which can result in the wrong
234		 * interface being assigned to the packet when fed back
235		 * into the divert socket. Theoretically if the daemon saves
236		 * and re-uses the sockaddr_in as suggested in the man pages,
237		 * this iface name will come along for the ride.
238		 * (see div_output for the other half of this.)
239		 */
240		strlcpy(divsrc.sin_zero, m->m_pkthdr.rcvif->if_xname,
241		    sizeof(divsrc.sin_zero));
242	}
243
244	/* Put packet on socket queue, if any */
245	sa = NULL;
246	nport = htons((u_int16_t)divert_info(mtag));
247	INP_INFO_RLOCK(&divcbinfo);
248	LIST_FOREACH(inp, &divcb, inp_list) {
249		INP_LOCK(inp);
250		/* XXX why does only one socket match? */
251		if (inp->inp_lport == nport) {
252			sa = inp->inp_socket;
253			SOCKBUF_LOCK(&sa->so_rcv);
254			if (sbappendaddr_locked(&sa->so_rcv,
255			    (struct sockaddr *)&divsrc, m,
256			    (struct mbuf *)0) == 0) {
257				SOCKBUF_UNLOCK(&sa->so_rcv);
258				sa = NULL;	/* force mbuf reclaim below */
259			} else
260				sorwakeup_locked(sa);
261			INP_UNLOCK(inp);
262			break;
263		}
264		INP_UNLOCK(inp);
265	}
266	INP_INFO_RUNLOCK(&divcbinfo);
267	if (sa == NULL) {
268		m_freem(m);
269		ipstat.ips_noproto++;
270		ipstat.ips_delivered--;
271        }
272}
273
274/*
275 * Deliver packet back into the IP processing machinery.
276 *
277 * If no address specified, or address is 0.0.0.0, send to ip_output();
278 * otherwise, send to ip_input() and mark as having been received on
279 * the interface with that address.
280 */
281static int
282div_output(struct socket *so, struct mbuf *m,
283	struct sockaddr_in *sin, struct mbuf *control)
284{
285	struct m_tag *mtag;
286	struct divert_tag *dt;
287	int error = 0;
288
289	/*
290	 * An mbuf may hasn't come from userland, but we pretend
291	 * that it has.
292	 */
293	m->m_pkthdr.rcvif = NULL;
294	m->m_nextpkt = NULL;
295
296	if (control)
297		m_freem(control);		/* XXX */
298
299	if ((mtag = m_tag_find(m, PACKET_TAG_DIVERT, NULL)) == NULL) {
300		mtag = m_tag_get(PACKET_TAG_DIVERT, sizeof(struct divert_tag),
301		    M_NOWAIT | M_ZERO);
302		if (mtag == NULL) {
303			error = ENOBUFS;
304			goto cantsend;
305		}
306		dt = (struct divert_tag *)(mtag+1);
307		m_tag_prepend(m, mtag);
308	} else
309		dt = (struct divert_tag *)(mtag+1);
310
311	/* Loopback avoidance and state recovery */
312	if (sin) {
313		int i;
314
315		dt->cookie = sin->sin_port;
316		/*
317		 * Find receive interface with the given name, stuffed
318		 * (if it exists) in the sin_zero[] field.
319		 * The name is user supplied data so don't trust its size
320		 * or that it is zero terminated.
321		 */
322		for (i = 0; i < sizeof(sin->sin_zero) && sin->sin_zero[i]; i++)
323			;
324		if ( i > 0 && i < sizeof(sin->sin_zero))
325			m->m_pkthdr.rcvif = ifunit(sin->sin_zero);
326	}
327
328	/* Reinject packet into the system as incoming or outgoing */
329	if (!sin || sin->sin_addr.s_addr == 0) {
330		struct ip *const ip = mtod(m, struct ip *);
331		struct inpcb *inp;
332
333		dt->info |= IP_FW_DIVERT_OUTPUT_FLAG;
334		INP_INFO_WLOCK(&divcbinfo);
335		inp = sotoinpcb(so);
336		INP_LOCK(inp);
337		/*
338		 * Don't allow both user specified and setsockopt options,
339		 * and don't allow packet length sizes that will crash
340		 */
341		if (((ip->ip_hl != (sizeof (*ip) >> 2)) && inp->inp_options) ||
342		     ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) {
343			error = EINVAL;
344			m_freem(m);
345		} else {
346			/* Convert fields to host order for ip_output() */
347			ip->ip_len = ntohs(ip->ip_len);
348			ip->ip_off = ntohs(ip->ip_off);
349
350			/* Send packet to output processing */
351			ipstat.ips_rawout++;			/* XXX */
352
353#ifdef MAC
354			mac_create_mbuf_from_inpcb(inp, m);
355#endif
356			error = ip_output(m,
357				    inp->inp_options, NULL,
358				    ((so->so_options & SO_DONTROUTE) ?
359				    IP_ROUTETOIF : 0) |
360				    IP_ALLOWBROADCAST | IP_RAWOUTPUT,
361				    inp->inp_moptions, NULL);
362		}
363		INP_UNLOCK(inp);
364		INP_INFO_WUNLOCK(&divcbinfo);
365	} else {
366		dt->info |= IP_FW_DIVERT_LOOPBACK_FLAG;
367		if (m->m_pkthdr.rcvif == NULL) {
368			/*
369			 * No luck with the name, check by IP address.
370			 * Clear the port and the ifname to make sure
371			 * there are no distractions for ifa_ifwithaddr.
372			 */
373			struct	ifaddr *ifa;
374
375			bzero(sin->sin_zero, sizeof(sin->sin_zero));
376			sin->sin_port = 0;
377			ifa = ifa_ifwithaddr((struct sockaddr *) sin);
378			if (ifa == NULL) {
379				error = EADDRNOTAVAIL;
380				goto cantsend;
381			}
382			m->m_pkthdr.rcvif = ifa->ifa_ifp;
383		}
384#ifdef MAC
385		SOCK_LOCK(so);
386		mac_create_mbuf_from_socket(so, m);
387		SOCK_UNLOCK(so);
388#endif
389		/* Send packet to input processing */
390		ip_input(m);
391	}
392
393	return error;
394
395cantsend:
396	m_freem(m);
397	return error;
398}
399
400static int
401div_attach(struct socket *so, int proto, struct thread *td)
402{
403	struct inpcb *inp;
404	int error;
405
406	inp  = sotoinpcb(so);
407	KASSERT(inp == NULL, ("div_attach: inp != NULL"));
408	if (td && (error = suser(td)) != 0)
409		return error;
410	error = soreserve(so, div_sendspace, div_recvspace);
411	if (error)
412		return error;
413	INP_INFO_WLOCK(&divcbinfo);
414	error = in_pcballoc(so, &divcbinfo, "divinp");
415	if (error) {
416		INP_INFO_WUNLOCK(&divcbinfo);
417		return error;
418	}
419	inp = (struct inpcb *)so->so_pcb;
420	INP_LOCK(inp);
421	INP_INFO_WUNLOCK(&divcbinfo);
422	inp->inp_ip_p = proto;
423	inp->inp_vflag |= INP_IPV4;
424	inp->inp_flags |= INP_HDRINCL;
425	INP_UNLOCK(inp);
426	return 0;
427}
428
429static void
430div_detach(struct socket *so)
431{
432	struct inpcb *inp;
433
434	inp = sotoinpcb(so);
435	KASSERT(inp != NULL, ("div_detach: inp == NULL"));
436	INP_INFO_WLOCK(&divcbinfo);
437	INP_LOCK(inp);
438	in_pcbdetach(inp);
439	in_pcbfree(inp);
440	INP_INFO_WUNLOCK(&divcbinfo);
441}
442
443static int
444div_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
445{
446	struct inpcb *inp;
447	int error;
448
449	inp = sotoinpcb(so);
450	KASSERT(inp != NULL, ("div_bind: inp == NULL"));
451	/* in_pcbbind assumes that nam is a sockaddr_in
452	 * and in_pcbbind requires a valid address. Since divert
453	 * sockets don't we need to make sure the address is
454	 * filled in properly.
455	 * XXX -- divert should not be abusing in_pcbind
456	 * and should probably have its own family.
457	 */
458	if (nam->sa_family != AF_INET)
459		return EAFNOSUPPORT;
460	((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY;
461	INP_INFO_WLOCK(&divcbinfo);
462	INP_LOCK(inp);
463	error = in_pcbbind(inp, nam, td->td_ucred);
464	INP_UNLOCK(inp);
465	INP_INFO_WUNLOCK(&divcbinfo);
466	return error;
467}
468
469static int
470div_shutdown(struct socket *so)
471{
472	struct inpcb *inp;
473
474	inp = sotoinpcb(so);
475	KASSERT(inp != NULL, ("div_shutdown: inp == NULL"));
476	INP_LOCK(inp);
477	socantsendmore(so);
478	INP_UNLOCK(inp);
479	return 0;
480}
481
482static int
483div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
484	 struct mbuf *control, struct thread *td)
485{
486	/* Packet must have a header (but that's about it) */
487	if (m->m_len < sizeof (struct ip) &&
488	    (m = m_pullup(m, sizeof (struct ip))) == 0) {
489		ipstat.ips_toosmall++;
490		m_freem(m);
491		return EINVAL;
492	}
493
494	/* Send packet */
495	return div_output(so, m, (struct sockaddr_in *)nam, control);
496}
497
498void
499div_ctlinput(int cmd, struct sockaddr *sa, void *vip)
500{
501        struct in_addr faddr;
502
503	faddr = ((struct sockaddr_in *)sa)->sin_addr;
504	if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
505        	return;
506	if (PRC_IS_REDIRECT(cmd))
507		return;
508}
509
510static int
511div_pcblist(SYSCTL_HANDLER_ARGS)
512{
513	int error, i, n;
514	struct inpcb *inp, **inp_list;
515	inp_gen_t gencnt;
516	struct xinpgen xig;
517
518	/*
519	 * The process of preparing the TCB list is too time-consuming and
520	 * resource-intensive to repeat twice on every request.
521	 */
522	if (req->oldptr == 0) {
523		n = divcbinfo.ipi_count;
524		req->oldidx = 2 * (sizeof xig)
525			+ (n + n/8) * sizeof(struct xinpcb);
526		return 0;
527	}
528
529	if (req->newptr != 0)
530		return EPERM;
531
532	/*
533	 * OK, now we're committed to doing something.
534	 */
535	INP_INFO_RLOCK(&divcbinfo);
536	gencnt = divcbinfo.ipi_gencnt;
537	n = divcbinfo.ipi_count;
538	INP_INFO_RUNLOCK(&divcbinfo);
539
540	error = sysctl_wire_old_buffer(req,
541	    2 * sizeof(xig) + n*sizeof(struct xinpcb));
542	if (error != 0)
543		return (error);
544
545	xig.xig_len = sizeof xig;
546	xig.xig_count = n;
547	xig.xig_gen = gencnt;
548	xig.xig_sogen = so_gencnt;
549	error = SYSCTL_OUT(req, &xig, sizeof xig);
550	if (error)
551		return error;
552
553	inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
554	if (inp_list == 0)
555		return ENOMEM;
556
557	INP_INFO_RLOCK(&divcbinfo);
558	for (inp = LIST_FIRST(divcbinfo.listhead), i = 0; inp && i < n;
559	     inp = LIST_NEXT(inp, inp_list)) {
560		INP_LOCK(inp);
561		if (inp->inp_gencnt <= gencnt &&
562		    cr_canseesocket(req->td->td_ucred, inp->inp_socket) == 0)
563			inp_list[i++] = inp;
564		INP_UNLOCK(inp);
565	}
566	INP_INFO_RUNLOCK(&divcbinfo);
567	n = i;
568
569	error = 0;
570	for (i = 0; i < n; i++) {
571		inp = inp_list[i];
572		if (inp->inp_gencnt <= gencnt) {
573			struct xinpcb xi;
574			bzero(&xi, sizeof(xi));
575			xi.xi_len = sizeof xi;
576			/* XXX should avoid extra copy */
577			bcopy(inp, &xi.xi_inp, sizeof *inp);
578			if (inp->inp_socket)
579				sotoxsocket(inp->inp_socket, &xi.xi_socket);
580			error = SYSCTL_OUT(req, &xi, sizeof xi);
581		}
582	}
583	if (!error) {
584		/*
585		 * Give the user an updated idea of our state.
586		 * If the generation differs from what we told
587		 * her before, she knows that something happened
588		 * while we were processing this request, and it
589		 * might be necessary to retry.
590		 */
591		INP_INFO_RLOCK(&divcbinfo);
592		xig.xig_gen = divcbinfo.ipi_gencnt;
593		xig.xig_sogen = so_gencnt;
594		xig.xig_count = divcbinfo.ipi_count;
595		INP_INFO_RUNLOCK(&divcbinfo);
596		error = SYSCTL_OUT(req, &xig, sizeof xig);
597	}
598	free(inp_list, M_TEMP);
599	return error;
600}
601
602/*
603 * This is the wrapper function for in_setsockaddr.  We just pass down
604 * the pcbinfo for in_setpeeraddr to lock.
605 */
606static int
607div_sockaddr(struct socket *so, struct sockaddr **nam)
608{
609	return (in_setsockaddr(so, nam, &divcbinfo));
610}
611
612/*
613 * This is the wrapper function for in_setpeeraddr. We just pass down
614 * the pcbinfo for in_setpeeraddr to lock.
615 */
616static int
617div_peeraddr(struct socket *so, struct sockaddr **nam)
618{
619	return (in_setpeeraddr(so, nam, &divcbinfo));
620}
621
622#ifdef SYSCTL_NODE
623SYSCTL_NODE(_net_inet, IPPROTO_DIVERT, divert, CTLFLAG_RW, 0, "IPDIVERT");
624SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, 0, 0,
625	    div_pcblist, "S,xinpcb", "List of active divert sockets");
626#endif
627
628struct pr_usrreqs div_usrreqs = {
629	.pru_attach =		div_attach,
630	.pru_bind =		div_bind,
631	.pru_control =		in_control,
632	.pru_detach =		div_detach,
633	.pru_peeraddr =		div_peeraddr,
634	.pru_send =		div_send,
635	.pru_shutdown =		div_shutdown,
636	.pru_sockaddr =		div_sockaddr,
637	.pru_sosetlabel =	in_pcbsosetlabel
638};
639
640struct protosw div_protosw = {
641	.pr_type =		SOCK_RAW,
642	.pr_protocol =		IPPROTO_DIVERT,
643	.pr_flags =		PR_ATOMIC|PR_ADDR,
644	.pr_input =		div_input,
645	.pr_ctlinput =		div_ctlinput,
646	.pr_ctloutput =		ip_ctloutput,
647	.pr_init =		div_init,
648	.pr_usrreqs =		&div_usrreqs
649};
650
651static int
652div_modevent(module_t mod, int type, void *unused)
653{
654	int err = 0;
655	int n;
656
657	switch (type) {
658	case MOD_LOAD:
659		/*
660		 * Protocol will be initialized by pf_proto_register().
661		 * We don't have to register ip_protox because we are not
662		 * a true IP protocol that goes over the wire.
663		 */
664		err = pf_proto_register(PF_INET, &div_protosw);
665		ip_divert_ptr = divert_packet;
666		break;
667	case MOD_QUIESCE:
668		/*
669		 * IPDIVERT may normally not be unloaded because of the
670		 * potential race conditions.  Tell kldunload we can't be
671		 * unloaded unless the unload is forced.
672		 */
673		err = EPERM;
674		break;
675	case MOD_UNLOAD:
676		/*
677		 * Forced unload.
678		 *
679		 * Module ipdivert can only be unloaded if no sockets are
680		 * connected.  Maybe this can be changed later to forcefully
681		 * disconnect any open sockets.
682		 *
683		 * XXXRW: Note that there is a slight race here, as a new
684		 * socket open request could be spinning on the lock and then
685		 * we destroy the lock.
686		 */
687		INP_INFO_WLOCK(&divcbinfo);
688		n = divcbinfo.ipi_count;
689		if (n != 0) {
690			err = EBUSY;
691			INP_INFO_WUNLOCK(&divcbinfo);
692			break;
693		}
694		ip_divert_ptr = NULL;
695		err = pf_proto_unregister(PF_INET, IPPROTO_DIVERT, SOCK_RAW);
696		INP_INFO_WUNLOCK(&divcbinfo);
697		INP_INFO_LOCK_DESTROY(&divcbinfo);
698		uma_zdestroy(divcbinfo.ipi_zone);
699		break;
700	default:
701		err = EOPNOTSUPP;
702		break;
703	}
704	return err;
705}
706
707static moduledata_t ipdivertmod = {
708        "ipdivert",
709        div_modevent,
710        0
711};
712
713DECLARE_MODULE(ipdivert, ipdivertmod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
714MODULE_DEPEND(dummynet, ipfw, 2, 2, 2);
715MODULE_VERSION(ipdivert, 1);
716