xref: /dragonfly/sys/netinet/ip_divert.c (revision 267c04fd)
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  * 3. 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: src/sys/netinet/ip_divert.c,v 1.42.2.6 2003/01/23 21:06:45 sam Exp $
30  */
31 
32 #define	_IP_VHL
33 
34 #include "opt_inet.h"
35 #include "opt_ipdivert.h"
36 #include "opt_ipsec.h"
37 
38 #ifndef INET
39 #error "IPDIVERT requires INET."
40 #endif
41 
42 #include <sys/param.h>
43 #include <sys/kernel.h>
44 #include <sys/malloc.h>
45 #include <sys/mbuf.h>
46 #include <sys/socket.h>
47 #include <sys/protosw.h>
48 #include <sys/socketvar.h>
49 #include <sys/socketvar2.h>
50 #include <sys/sysctl.h>
51 #include <sys/systm.h>
52 #include <sys/proc.h>
53 #include <sys/priv.h>
54 #include <sys/in_cksum.h>
55 #include <sys/lock.h>
56 #include <sys/msgport.h>
57 
58 #include <net/if.h>
59 #include <net/route.h>
60 
61 #include <net/netmsg2.h>
62 #include <net/netisr2.h>
63 #include <sys/thread2.h>
64 #include <sys/mplock2.h>
65 
66 #include <netinet/in.h>
67 #include <netinet/in_systm.h>
68 #include <netinet/ip.h>
69 #include <netinet/in_pcb.h>
70 #include <netinet/in_var.h>
71 #include <netinet/ip_var.h>
72 #include <netinet/ip_divert.h>
73 
74 /*
75  * Divert sockets
76  */
77 
78 /*
79  * Allocate enough space to hold a full IP packet
80  */
81 #define	DIVSNDQ		(65536 + 100)
82 #define	DIVRCVQ		(65536 + 100)
83 
84 #define DIV_IS_OUTPUT(sin)	((sin) == NULL || (sin)->sin_addr.s_addr == 0)
85 
86 #define DIV_OUTPUT	0x10000
87 #define DIV_INPUT	0x20000
88 
89 /*
90  * Divert sockets work in conjunction with ipfw, see the divert(4)
91  * manpage for features.
92  * Internally, packets selected by ipfw in ip_input() or ip_output(),
93  * and never diverted before, are passed to the input queue of the
94  * divert socket with a given 'divert_port' number (as specified in
95  * the matching ipfw rule), and they are tagged with a 16 bit cookie
96  * (representing the rule number of the matching ipfw rule), which
97  * is passed to process reading from the socket.
98  *
99  * Packets written to the divert socket are again tagged with a cookie
100  * (usually the same as above) and a destination address.
101  * If the destination address is INADDR_ANY then the packet is
102  * treated as outgoing and sent to ip_output(), otherwise it is
103  * treated as incoming and sent to ip_input().
104  * In both cases, the packet is tagged with the cookie.
105  *
106  * On reinjection, processing in ip_input() and ip_output()
107  * will be exactly the same as for the original packet, except that
108  * ipfw processing will start at the rule number after the one
109  * written in the cookie (so, tagging a packet with a cookie of 0
110  * will cause it to be effectively considered as a standard packet).
111  */
112 
113 /* Internal variables */
114 static struct inpcbinfo divcbinfo;
115 static struct inpcbportinfo divcbportinfo;
116 
117 static u_long	div_sendspace = DIVSNDQ;	/* XXX sysctl ? */
118 static u_long	div_recvspace = DIVRCVQ;	/* XXX sysctl ? */
119 
120 static struct mbuf *ip_divert(struct mbuf *, int, int);
121 
122 /*
123  * Initialize divert connection block queue.
124  */
125 void
126 div_init(void)
127 {
128 	in_pcbinfo_init(&divcbinfo, 0, FALSE);
129 	in_pcbportinfo_init(&divcbportinfo, 1, FALSE, 0);
130 	/*
131 	 * XXX We don't use the hash list for divert IP, but it's easier
132 	 * to allocate a one entry hash list than it is to check all
133 	 * over the place for hashbase == NULL.
134 	 */
135 	divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask);
136 	divcbinfo.portinfo = &divcbportinfo;
137 	divcbinfo.wildcardhashbase = hashinit(1, M_PCB,
138 					      &divcbinfo.wildcardhashmask);
139 	divcbinfo.ipi_size = sizeof(struct inpcb);
140 	ip_divert_p = ip_divert;
141 }
142 
143 /*
144  * IPPROTO_DIVERT is not a real IP protocol; don't allow any packets
145  * with that protocol number to enter the system from the outside.
146  */
147 int
148 div_input(struct mbuf **mp, int *offp, int proto)
149 {
150 	struct mbuf *m = *mp;
151 
152 	ipstat.ips_noproto++;
153 	m_freem(m);
154 	return(IPPROTO_DONE);
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  */
163 static void
164 div_packet(struct mbuf *m, int incoming, int port)
165 {
166 	struct sockaddr_in divsrc = { sizeof divsrc, AF_INET };
167 	struct inpcb *inp;
168 	struct socket *sa;
169 	struct m_tag *mtag;
170 	struct divert_info *divinfo;
171 	u_int16_t nport;
172 
173 	KASSERT(&curthread->td_msgport == netisr_cpuport(0),
174 	    ("not in netisr0"));
175 
176 	/* Locate the divert info */
177 	mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
178 	divinfo = m_tag_data(mtag);
179 	divsrc.sin_port = divinfo->skipto;
180 
181 	/*
182 	 * Record receive interface address, if any.
183 	 * But only for incoming packets.
184 	 */
185 	divsrc.sin_addr.s_addr = 0;
186 	if (incoming) {
187 		struct ifaddr_container *ifac;
188 
189 		/* Find IP address for receive interface */
190 		TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid],
191 			      ifa_link) {
192 			struct ifaddr *ifa = ifac->ifa;
193 
194 			if (ifa->ifa_addr == NULL)
195 				continue;
196 			if (ifa->ifa_addr->sa_family != AF_INET)
197 				continue;
198 			divsrc.sin_addr =
199 			    ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr;
200 			break;
201 		}
202 	}
203 	/*
204 	 * Record the incoming interface name whenever we have one.
205 	 */
206 	if (m->m_pkthdr.rcvif) {
207 		/*
208 		 * Hide the actual interface name in there in the
209 		 * sin_zero array. XXX This needs to be moved to a
210 		 * different sockaddr type for divert, e.g.
211 		 * sockaddr_div with multiple fields like
212 		 * sockaddr_dl. Presently we have only 7 bytes
213 		 * but that will do for now as most interfaces
214 		 * are 4 or less + 2 or less bytes for unit.
215 		 * There is probably a faster way of doing this,
216 		 * possibly taking it from the sockaddr_dl on the iface.
217 		 * This solves the problem of a P2P link and a LAN interface
218 		 * having the same address, which can result in the wrong
219 		 * interface being assigned to the packet when fed back
220 		 * into the divert socket. Theoretically if the daemon saves
221 		 * and re-uses the sockaddr_in as suggested in the man pages,
222 		 * this iface name will come along for the ride.
223 		 * (see div_output for the other half of this.)
224 		 */
225 		ksnprintf(divsrc.sin_zero, sizeof divsrc.sin_zero, "%s",
226 			  m->m_pkthdr.rcvif->if_xname);
227 	}
228 
229 	/* Put packet on socket queue, if any */
230 	sa = NULL;
231 	nport = htons((u_int16_t)port);
232 
233 	/*
234 	 * Following loop to locate the inpcb is MPSAFE since the inpcb
235 	 * insertion/removal happens on the same CPU (CPU0).
236 	 */
237 	LIST_FOREACH(inp, &divcbinfo.pcblisthead, inp_list) {
238 		if (inp->inp_flags & INP_PLACEMARKER)
239 			continue;
240 		if (inp->inp_lport == nport)
241 			sa = inp->inp_socket;
242 	}
243 	if (sa) {
244 		lwkt_gettoken(&sa->so_rcv.ssb_token);
245 		if (ssb_appendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, m, NULL) == 0)
246 			m_freem(m);
247 		else
248 			sorwakeup(sa);
249 		lwkt_reltoken(&sa->so_rcv.ssb_token);
250 	} else {
251 		m_freem(m);
252 		ipstat.ips_noproto++;
253 		ipstat.ips_delivered--;
254 	}
255 }
256 
257 static void
258 div_packet_handler(netmsg_t msg)
259 {
260 	struct mbuf *m;
261 	int port, incoming = 0;
262 
263 	m = msg->packet.nm_packet;
264 
265 	port = msg->lmsg.u.ms_result32 & 0xffff;
266 	if (msg->lmsg.u.ms_result32 & DIV_INPUT)
267 		incoming = 1;
268 	div_packet(m, incoming, port);
269 	/* no reply, msg embedded in mbuf */
270 }
271 
272 static void
273 divert_packet(struct mbuf *m, int incoming)
274 {
275 	struct m_tag *mtag;
276 	struct divert_info *divinfo;
277 	int port;
278 
279 	M_ASSERTPKTHDR(m);
280 
281 	/* Assure header */
282 	if (m->m_len < sizeof(struct ip) &&
283 	    (m = m_pullup(m, sizeof(struct ip))) == NULL)
284 		return;
285 
286 	mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
287 	KASSERT(mtag != NULL, ("%s no divert tag!", __func__));
288 	divinfo = m_tag_data(mtag);
289 
290 	port = divinfo->port;
291 	KASSERT(port != 0, ("%s: port=0", __func__));
292 
293 	if (mycpuid != 0) {
294 		struct netmsg_packet *nmp;
295 
296 		nmp = &m->m_hdr.mh_netmsg;
297 		netmsg_init(&nmp->base, NULL, &netisr_apanic_rport,
298 			    0, div_packet_handler);
299 		nmp->nm_packet = m;
300 
301 		nmp->base.lmsg.u.ms_result32 = port; /* port is 16bits */
302 		if (incoming)
303 			nmp->base.lmsg.u.ms_result32 |= DIV_INPUT;
304 		else
305 			nmp->base.lmsg.u.ms_result32 |= DIV_OUTPUT;
306 
307 		lwkt_sendmsg(netisr_cpuport(0), &nmp->base.lmsg);
308 	} else {
309 		div_packet(m, incoming, port);
310 	}
311 }
312 
313 /*
314  * Deliver packet back into the IP processing machinery.
315  *
316  * If no address specified, or address is 0.0.0.0, send to ip_output();
317  * otherwise, send to ip_input() and mark as having been received on
318  * the interface with that address.
319  */
320 static int
321 div_output(struct socket *so, struct mbuf *m,
322 	struct sockaddr_in *sin, struct mbuf *control)
323 {
324 	int error = 0;
325 	struct m_tag *mtag;
326 	struct divert_info *divinfo;
327 
328 	KASSERT(&curthread->td_msgport == netisr_cpuport(0),
329 	    ("not in netisr0"));
330 
331 	if (control)
332 		m_freem(control);		/* XXX */
333 
334 	/*
335 	 * Prepare the tag for divert info. Note that a packet
336 	 * with a 0 tag in mh_data is effectively untagged,
337 	 * so we could optimize that case.
338 	 */
339 	mtag = m_tag_get(PACKET_TAG_IPFW_DIVERT, sizeof(*divinfo), M_NOWAIT);
340 	if (mtag == NULL) {
341 		error = ENOBUFS;
342 		goto cantsend;
343 	}
344 	m_tag_prepend(m, mtag);
345 
346 	/* Loopback avoidance and state recovery */
347 	divinfo = m_tag_data(mtag);
348 	if (sin)
349 		divinfo->skipto = sin->sin_port;
350 	else
351 		divinfo->skipto = 0;
352 
353 	/* Reinject packet into the system as incoming or outgoing */
354 	if (DIV_IS_OUTPUT(sin)) {
355 		struct ip *const ip = mtod(m, struct ip *);
356 
357 		/* Don't allow packet length sizes that will crash */
358 		if ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len) {
359 			error = EINVAL;
360 			goto cantsend;
361 		}
362 
363 		/* Convert fields to host order for ip_output() */
364 		ip->ip_len = ntohs(ip->ip_len);
365 		ip->ip_off = ntohs(ip->ip_off);
366 
367 		/* Send packet to output processing */
368 		ipstat.ips_rawout++;			/* XXX */
369 		error = ip_output(m, NULL, NULL,
370 			    (so->so_options & SO_DONTROUTE) |
371 			    IP_ALLOWBROADCAST | IP_RAWOUTPUT,
372 			    NULL, NULL);
373 	} else {
374 		ip_input(m);
375 	}
376 	return error;
377 
378 cantsend:
379 	m_freem(m);
380 	return error;
381 }
382 
383 static void
384 div_attach(netmsg_t msg)
385 {
386 	struct socket *so = msg->attach.base.nm_so;
387 	int proto = msg->attach.nm_proto;
388 	struct pru_attach_info *ai = msg->attach.nm_ai;
389 	struct inpcb *inp;
390 	int error;
391 
392 	KASSERT(&curthread->td_msgport == netisr_cpuport(0),
393 	    ("not in netisr0"));
394 
395 	inp  = so->so_pcb;
396 	if (inp)
397 		panic("div_attach");
398 	error = priv_check_cred(ai->p_ucred, PRIV_ROOT, NULL_CRED_OKAY);
399 	if (error)
400 		goto out;
401 
402 	error = soreserve(so, div_sendspace, div_recvspace, ai->sb_rlimit);
403 	if (error)
404 		goto out;
405 	error = in_pcballoc(so, &divcbinfo);
406 	if (error)
407 		goto out;
408 	inp = (struct inpcb *)so->so_pcb;
409 	inp->inp_ip_p = proto;
410 	inp->inp_flags |= INP_HDRINCL;
411 	/*
412 	 * The socket is always "connected" because
413 	 * we always know "where" to send the packet.
414 	 */
415 	sosetstate(so, SS_ISCONNECTED);
416 	error = 0;
417 out:
418 	lwkt_replymsg(&msg->attach.base.lmsg, error);
419 }
420 
421 static void
422 div_detach(netmsg_t msg)
423 {
424 	struct socket *so = msg->detach.base.nm_so;
425 	struct inpcb *inp;
426 
427 	KASSERT(&curthread->td_msgport == netisr_cpuport(0),
428 	    ("not in netisr0"));
429 
430 	inp = so->so_pcb;
431 	if (inp == NULL)
432 		panic("div_detach");
433 	in_pcbdetach(inp);
434 	lwkt_replymsg(&msg->detach.base.lmsg, 0);
435 }
436 
437 static void
438 div_abort(netmsg_t msg)
439 {
440 	/*
441 	 * Divert socket does not support listen(2),
442 	 * so this should never be called.
443 	 */
444 	panic("div_abort is called");
445 }
446 
447 static void
448 div_disconnect(netmsg_t msg)
449 {
450 	struct socket *so = msg->disconnect.base.nm_so;
451 	int error;
452 
453 	KASSERT(&curthread->td_msgport == netisr_cpuport(0),
454 	    ("not in netisr0"));
455 
456 	if (so->so_state & SS_ISCONNECTED) {
457 		soisdisconnected(so);
458 		error = 0;
459 	} else {
460 		error = ENOTCONN;
461 	}
462 	lwkt_replymsg(&msg->disconnect.base.lmsg, error);
463 }
464 
465 static void
466 div_bind(netmsg_t msg)
467 {
468 	struct socket *so = msg->bind.base.nm_so;
469 	struct sockaddr *nam = msg->bind.nm_nam;
470 	int error;
471 
472 	KASSERT(&curthread->td_msgport == netisr_cpuport(0),
473 	    ("not in netisr0"));
474 
475 	/*
476 	 * in_pcbbind assumes that nam is a sockaddr_in
477 	 * and in_pcbbind requires a valid address. Since divert
478 	 * sockets don't we need to make sure the address is
479 	 * filled in properly.
480 	 * XXX -- divert should not be abusing in_pcbind
481 	 * and should probably have its own family.
482 	 */
483 	if (nam->sa_family != AF_INET) {
484 		error = EAFNOSUPPORT;
485 	} else {
486 		((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY;
487 		error = in_pcbbind(so->so_pcb, nam, msg->bind.nm_td);
488 	}
489 	lwkt_replymsg(&msg->bind.base.lmsg, error);
490 }
491 
492 static void
493 div_shutdown(netmsg_t msg)
494 {
495 	struct socket *so = msg->shutdown.base.nm_so;
496 
497 	KASSERT(&curthread->td_msgport == netisr_cpuport(0),
498 	    ("not in netisr0"));
499 
500 	socantsendmore(so);
501 
502 	lwkt_replymsg(&msg->shutdown.base.lmsg, 0);
503 }
504 
505 static void
506 div_send(netmsg_t msg)
507 {
508 	struct socket *so = msg->send.base.nm_so;
509 	struct mbuf *m = msg->send.nm_m;
510 	struct sockaddr *nam = msg->send.nm_addr;
511 	struct mbuf *control = msg->send.nm_control;
512 	int error;
513 
514 	/* Length check already done in ip_hashfn() */
515 	KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf"));
516 
517 	/* Send packet */
518 	error = div_output(so, m, (struct sockaddr_in *)nam, control);
519 	lwkt_replymsg(&msg->send.base.lmsg, error);
520 }
521 
522 SYSCTL_DECL(_net_inet_divert);
523 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, &divcbinfo, 1,
524 	    in_pcblist_global, "S,xinpcb", "List of active divert sockets");
525 
526 struct pr_usrreqs div_usrreqs = {
527 	.pru_abort = div_abort,
528 	.pru_accept = pr_generic_notsupp,
529 	.pru_attach = div_attach,
530 	.pru_bind = div_bind,
531 	.pru_connect = pr_generic_notsupp,
532 	.pru_connect2 = pr_generic_notsupp,
533 	.pru_control = in_control_dispatch,
534 	.pru_detach = div_detach,
535 	.pru_disconnect = div_disconnect,
536 	.pru_listen = pr_generic_notsupp,
537 	.pru_peeraddr = in_setpeeraddr_dispatch,
538 	.pru_rcvd = pr_generic_notsupp,
539 	.pru_rcvoob = pr_generic_notsupp,
540 	.pru_send = div_send,
541 	.pru_sense = pru_sense_null,
542 	.pru_shutdown = div_shutdown,
543 	.pru_sockaddr = in_setsockaddr_dispatch,
544 	.pru_sosend = sosend,
545 	.pru_soreceive = soreceive
546 };
547 
548 static struct mbuf *
549 ip_divert_out(struct mbuf *m, int tee)
550 {
551 	struct mbuf *clone = NULL;
552 	struct ip *ip = mtod(m, struct ip *);
553 
554 	/* Clone packet if we're doing a 'tee' */
555 	if (tee)
556 		clone = m_dup(m, M_NOWAIT);
557 
558 	/*
559 	 * XXX
560 	 * delayed checksums are not currently compatible
561 	 * with divert sockets.
562 	 */
563 	if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
564 		in_delayed_cksum(m);
565 		m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
566 	}
567 
568 	/* Restore packet header fields to original values */
569 	ip->ip_len = htons(ip->ip_len);
570 	ip->ip_off = htons(ip->ip_off);
571 
572 	/* Deliver packet to divert input routine */
573 	divert_packet(m, 0);
574 
575 	/* If 'tee', continue with original packet */
576 	return clone;
577 }
578 
579 static struct mbuf *
580 ip_divert_in(struct mbuf *m, int tee)
581 {
582 	struct mbuf *clone = NULL;
583 	struct ip *ip = mtod(m, struct ip *);
584 	struct m_tag *mtag;
585 
586 	if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
587 		const struct divert_info *divinfo;
588 		u_short frag_off;
589 		int hlen;
590 
591 		/*
592 		 * Only trust divert info in the fragment
593 		 * at offset 0.
594 		 */
595 		frag_off = ip->ip_off << 3;
596 		if (frag_off != 0) {
597 			mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
598 			m_tag_delete(m, mtag);
599 		}
600 
601 		/*
602 		 * Attempt reassembly; if it succeeds, proceed.
603 		 * ip_reass() will return a different mbuf.
604 		 */
605 		m = ip_reass(m);
606 		if (m == NULL)
607 			return NULL;
608 		ip = mtod(m, struct ip *);
609 
610 		/* Caller need to redispatch the packet, if it is for us */
611 		m->m_pkthdr.fw_flags |= FW_MBUF_REDISPATCH;
612 
613 		/*
614 		 * Get the header length of the reassembled
615 		 * packet
616 		 */
617 		hlen = IP_VHL_HL(ip->ip_vhl) << 2;
618 
619 		/*
620 		 * Restore original checksum before diverting
621 		 * packet
622 		 */
623 		ip->ip_len += hlen;
624 		ip->ip_len = htons(ip->ip_len);
625 		ip->ip_off = htons(ip->ip_off);
626 		ip->ip_sum = 0;
627 		if (hlen == sizeof(struct ip))
628 			ip->ip_sum = in_cksum_hdr(ip);
629 		else
630 			ip->ip_sum = in_cksum(m, hlen);
631 		ip->ip_off = ntohs(ip->ip_off);
632 		ip->ip_len = ntohs(ip->ip_len);
633 
634 		/*
635 		 * Only use the saved divert info
636 		 */
637 		mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
638 		if (mtag == NULL) {
639 			/* Wrongly configured ipfw */
640 			kprintf("ip_input no divert info\n");
641 			m_freem(m);
642 			return NULL;
643 		}
644 		divinfo = m_tag_data(mtag);
645 		tee = divinfo->tee;
646 	}
647 
648 	/*
649 	 * Divert or tee packet to the divert protocol if
650 	 * required.
651 	 */
652 
653 	/* Clone packet if we're doing a 'tee' */
654 	if (tee)
655 		clone = m_dup(m, M_NOWAIT);
656 
657 	/*
658 	 * Restore packet header fields to original
659 	 * values
660 	 */
661 	ip->ip_len = htons(ip->ip_len);
662 	ip->ip_off = htons(ip->ip_off);
663 
664 	/* Deliver packet to divert input routine */
665 	divert_packet(m, 1);
666 
667 	/* Catch invalid reference */
668 	m = NULL;
669 	ip = NULL;
670 
671 	ipstat.ips_delivered++;
672 
673 	/* If 'tee', continue with original packet */
674 	if (clone != NULL) {
675 		/*
676 		 * Complete processing of the packet.
677 		 * XXX Better safe than sorry, remove the DIVERT tag.
678 		 */
679 		mtag = m_tag_find(clone, PACKET_TAG_IPFW_DIVERT, NULL);
680 		KKASSERT(mtag != NULL);
681 		m_tag_delete(clone, mtag);
682 	}
683 	return clone;
684 }
685 
686 static struct mbuf *
687 ip_divert(struct mbuf *m, int tee, int incoming)
688 {
689 	struct mbuf *ret;
690 
691 	if (incoming)
692 		ret = ip_divert_in(m, tee);
693 	else
694 		ret = ip_divert_out(m, tee);
695 	return ret;
696 }
697