xref: /freebsd/sys/netinet/ip_divert.c (revision 6af83ee0d2941d18880b6aaa2b4facd1d30c6106)
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  * $FreeBSD$
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. */
110 static struct inpcbhead divcb;
111 static struct inpcbinfo divcbinfo;
112 
113 static u_long	div_sendspace = DIVSNDQ;	/* XXX sysctl ? */
114 static u_long	div_recvspace = DIVRCVQ;	/* XXX sysctl ? */
115 
116 /*
117  * Initialize divert connection block queue.
118  */
119 void
120 div_init(void)
121 {
122 	INP_INFO_LOCK_INIT(&divcbinfo, "div");
123 	LIST_INIT(&divcb);
124 	divcbinfo.listhead = &divcb;
125 	/*
126 	 * XXX We don't use the hash list for divert IP, but it's easier
127 	 * to allocate a one entry hash list than it is to check all
128 	 * over the place for hashbase == NULL.
129 	 */
130 	divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask);
131 	divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask);
132 	divcbinfo.ipi_zone = uma_zcreate("divcb", sizeof(struct inpcb),
133 	    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
134 	uma_zone_set_max(divcbinfo.ipi_zone, maxsockets);
135 }
136 
137 /*
138  * IPPROTO_DIVERT is not in the real IP protocol number space; this
139  * function should never be called.  Just in case, drop any packets.
140  */
141 void
142 div_input(struct mbuf *m, int off)
143 {
144 	ipstat.ips_noproto++;
145 	m_freem(m);
146 }
147 
148 /*
149  * Divert a packet by passing it up to the divert socket at port 'port'.
150  *
151  * Setup generic address and protocol structures for div_input routine,
152  * then pass them along with mbuf chain.
153  */
154 static void
155 divert_packet(struct mbuf *m, int incoming)
156 {
157 	struct ip *ip;
158 	struct inpcb *inp;
159 	struct socket *sa;
160 	u_int16_t nport;
161 	struct sockaddr_in divsrc;
162 	struct m_tag *mtag;
163 
164 	mtag = m_tag_find(m, PACKET_TAG_DIVERT, NULL);
165 	if (mtag == NULL) {
166 		printf("%s: no divert tag\n", __func__);
167 		m_freem(m);
168 		return;
169 	}
170 	/* Assure header */
171 	if (m->m_len < sizeof(struct ip) &&
172 	    (m = m_pullup(m, sizeof(struct ip))) == 0)
173 		return;
174 	ip = mtod(m, struct ip *);
175 
176 	/* Delayed checksums are currently not compatible with divert. */
177 	if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
178 		ip->ip_len = ntohs(ip->ip_len);
179 		in_delayed_cksum(m);
180 		m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
181 		ip->ip_len = htons(ip->ip_len);
182 	}
183 
184 	/*
185 	 * Record receive interface address, if any.
186 	 * But only for incoming packets.
187 	 */
188 	bzero(&divsrc, sizeof(divsrc));
189 	divsrc.sin_len = sizeof(divsrc);
190 	divsrc.sin_family = AF_INET;
191 	divsrc.sin_port = divert_cookie(mtag);	/* record matching rule */
192 	if (incoming) {
193 		struct ifaddr *ifa;
194 
195 		/* Sanity check */
196 		M_ASSERTPKTHDR(m);
197 
198 		/* Find IP address for receive interface */
199 		TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) {
200 			if (ifa->ifa_addr == NULL)
201 				continue;
202 			if (ifa->ifa_addr->sa_family != AF_INET)
203 				continue;
204 			divsrc.sin_addr =
205 			    ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr;
206 			break;
207 		}
208 	}
209 	/*
210 	 * Record the incoming interface name whenever we have one.
211 	 */
212 	if (m->m_pkthdr.rcvif) {
213 		/*
214 		 * Hide the actual interface name in there in the
215 		 * sin_zero array. XXX This needs to be moved to a
216 		 * different sockaddr type for divert, e.g.
217 		 * sockaddr_div with multiple fields like
218 		 * sockaddr_dl. Presently we have only 7 bytes
219 		 * but that will do for now as most interfaces
220 		 * are 4 or less + 2 or less bytes for unit.
221 		 * There is probably a faster way of doing this,
222 		 * possibly taking it from the sockaddr_dl on the iface.
223 		 * This solves the problem of a P2P link and a LAN interface
224 		 * having the same address, which can result in the wrong
225 		 * interface being assigned to the packet when fed back
226 		 * into the divert socket. Theoretically if the daemon saves
227 		 * and re-uses the sockaddr_in as suggested in the man pages,
228 		 * this iface name will come along for the ride.
229 		 * (see div_output for the other half of this.)
230 		 */
231 		strlcpy(divsrc.sin_zero, m->m_pkthdr.rcvif->if_xname,
232 		    sizeof(divsrc.sin_zero));
233 	}
234 
235 	/* Put packet on socket queue, if any */
236 	sa = NULL;
237 	nport = htons((u_int16_t)divert_info(mtag));
238 	INP_INFO_RLOCK(&divcbinfo);
239 	LIST_FOREACH(inp, &divcb, inp_list) {
240 		INP_LOCK(inp);
241 		/* XXX why does only one socket match? */
242 		if (inp->inp_lport == nport) {
243 			sa = inp->inp_socket;
244 			SOCKBUF_LOCK(&sa->so_rcv);
245 			if (sbappendaddr_locked(&sa->so_rcv,
246 			    (struct sockaddr *)&divsrc, m,
247 			    (struct mbuf *)0) == 0) {
248 				SOCKBUF_UNLOCK(&sa->so_rcv);
249 				sa = NULL;	/* force mbuf reclaim below */
250 			} else
251 				sorwakeup_locked(sa);
252 			INP_UNLOCK(inp);
253 			break;
254 		}
255 		INP_UNLOCK(inp);
256 	}
257 	INP_INFO_RUNLOCK(&divcbinfo);
258 	if (sa == NULL) {
259 		m_freem(m);
260 		ipstat.ips_noproto++;
261 		ipstat.ips_delivered--;
262         }
263 }
264 
265 /*
266  * Deliver packet back into the IP processing machinery.
267  *
268  * If no address specified, or address is 0.0.0.0, send to ip_output();
269  * otherwise, send to ip_input() and mark as having been received on
270  * the interface with that address.
271  */
272 static int
273 div_output(struct socket *so, struct mbuf *m,
274 	struct sockaddr_in *sin, struct mbuf *control)
275 {
276 	struct m_tag *mtag;
277 	struct divert_tag *dt;
278 	int error = 0;
279 
280 	m->m_pkthdr.rcvif = NULL;
281 
282 	if (control)
283 		m_freem(control);		/* XXX */
284 
285 	if ((mtag = m_tag_find(m, PACKET_TAG_DIVERT, NULL)) == NULL) {
286 		mtag = m_tag_get(PACKET_TAG_DIVERT, sizeof(struct divert_tag),
287 		    M_NOWAIT | M_ZERO);
288 		if (mtag == NULL) {
289 			error = ENOBUFS;
290 			goto cantsend;
291 		}
292 		dt = (struct divert_tag *)(mtag+1);
293 		m_tag_prepend(m, mtag);
294 	} else
295 		dt = (struct divert_tag *)(mtag+1);
296 
297 	/* Loopback avoidance and state recovery */
298 	if (sin) {
299 		int i;
300 
301 		dt->cookie = sin->sin_port;
302 		/*
303 		 * Find receive interface with the given name, stuffed
304 		 * (if it exists) in the sin_zero[] field.
305 		 * The name is user supplied data so don't trust its size
306 		 * or that it is zero terminated.
307 		 */
308 		for (i = 0; i < sizeof(sin->sin_zero) && sin->sin_zero[i]; i++)
309 			;
310 		if ( i > 0 && i < sizeof(sin->sin_zero))
311 			m->m_pkthdr.rcvif = ifunit(sin->sin_zero);
312 	}
313 
314 	/* Reinject packet into the system as incoming or outgoing */
315 	if (!sin || sin->sin_addr.s_addr == 0) {
316 		struct ip *const ip = mtod(m, struct ip *);
317 		struct inpcb *inp;
318 
319 		dt->info |= IP_FW_DIVERT_OUTPUT_FLAG;
320 		INP_INFO_WLOCK(&divcbinfo);
321 		inp = sotoinpcb(so);
322 		INP_LOCK(inp);
323 		/*
324 		 * Don't allow both user specified and setsockopt options,
325 		 * and don't allow packet length sizes that will crash
326 		 */
327 		if (((ip->ip_hl != (sizeof (*ip) >> 2)) && inp->inp_options) ||
328 		     ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) {
329 			error = EINVAL;
330 			m_freem(m);
331 		} else {
332 			/* Convert fields to host order for ip_output() */
333 			ip->ip_len = ntohs(ip->ip_len);
334 			ip->ip_off = ntohs(ip->ip_off);
335 
336 			/* Send packet to output processing */
337 			ipstat.ips_rawout++;			/* XXX */
338 
339 #ifdef MAC
340 			mac_create_mbuf_from_inpcb(inp, m);
341 #endif
342 			error = ip_output(m,
343 				    inp->inp_options, NULL,
344 				    ((so->so_options & SO_DONTROUTE) ?
345 				    IP_ROUTETOIF : 0) |
346 				    IP_ALLOWBROADCAST | IP_RAWOUTPUT,
347 				    inp->inp_moptions, NULL);
348 		}
349 		INP_UNLOCK(inp);
350 		INP_INFO_WUNLOCK(&divcbinfo);
351 	} else {
352 		dt->info |= IP_FW_DIVERT_LOOPBACK_FLAG;
353 		if (m->m_pkthdr.rcvif == NULL) {
354 			/*
355 			 * No luck with the name, check by IP address.
356 			 * Clear the port and the ifname to make sure
357 			 * there are no distractions for ifa_ifwithaddr.
358 			 */
359 			struct	ifaddr *ifa;
360 
361 			bzero(sin->sin_zero, sizeof(sin->sin_zero));
362 			sin->sin_port = 0;
363 			ifa = ifa_ifwithaddr((struct sockaddr *) sin);
364 			if (ifa == NULL) {
365 				error = EADDRNOTAVAIL;
366 				goto cantsend;
367 			}
368 			m->m_pkthdr.rcvif = ifa->ifa_ifp;
369 		}
370 #ifdef MAC
371 		SOCK_LOCK(so);
372 		mac_create_mbuf_from_socket(so, m);
373 		SOCK_UNLOCK(so);
374 #endif
375 		/* Send packet to input processing */
376 		ip_input(m);
377 	}
378 
379 	return error;
380 
381 cantsend:
382 	m_freem(m);
383 	return error;
384 }
385 
386 static int
387 div_attach(struct socket *so, int proto, struct thread *td)
388 {
389 	struct inpcb *inp;
390 	int error;
391 
392 	INP_INFO_WLOCK(&divcbinfo);
393 	inp  = sotoinpcb(so);
394 	if (inp != 0) {
395 		INP_INFO_WUNLOCK(&divcbinfo);
396 		return EINVAL;
397 	}
398 	if (td && (error = suser(td)) != 0) {
399 		INP_INFO_WUNLOCK(&divcbinfo);
400 		return error;
401 	}
402 	error = soreserve(so, div_sendspace, div_recvspace);
403 	if (error) {
404 		INP_INFO_WUNLOCK(&divcbinfo);
405 		return error;
406 	}
407 	error = in_pcballoc(so, &divcbinfo, "divinp");
408 	if (error) {
409 		INP_INFO_WUNLOCK(&divcbinfo);
410 		return error;
411 	}
412 	inp = (struct inpcb *)so->so_pcb;
413 	INP_LOCK(inp);
414 	INP_INFO_WUNLOCK(&divcbinfo);
415 	inp->inp_ip_p = proto;
416 	inp->inp_vflag |= INP_IPV4;
417 	inp->inp_flags |= INP_HDRINCL;
418 	INP_UNLOCK(inp);
419 	return 0;
420 }
421 
422 static int
423 div_detach(struct socket *so)
424 {
425 	struct inpcb *inp;
426 
427 	INP_INFO_WLOCK(&divcbinfo);
428 	inp = sotoinpcb(so);
429 	if (inp == 0) {
430 		INP_INFO_WUNLOCK(&divcbinfo);
431 		return EINVAL;
432 	}
433 	INP_LOCK(inp);
434 	in_pcbdetach(inp);
435 	INP_INFO_WUNLOCK(&divcbinfo);
436 	return 0;
437 }
438 
439 static int
440 div_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
441 {
442 	struct inpcb *inp;
443 	int error;
444 
445 	INP_INFO_WLOCK(&divcbinfo);
446 	inp = sotoinpcb(so);
447 	if (inp == 0) {
448 		INP_INFO_WUNLOCK(&divcbinfo);
449 		return EINVAL;
450 	}
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 		error = EAFNOSUPPORT;
460 	else {
461 		((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY;
462 		INP_LOCK(inp);
463 		error = in_pcbbind(inp, nam, td->td_ucred);
464 		INP_UNLOCK(inp);
465 	}
466 	INP_INFO_WUNLOCK(&divcbinfo);
467 	return error;
468 }
469 
470 static int
471 div_shutdown(struct socket *so)
472 {
473 	struct inpcb *inp;
474 
475 	INP_INFO_RLOCK(&divcbinfo);
476 	inp = sotoinpcb(so);
477 	if (inp == 0) {
478 		INP_INFO_RUNLOCK(&divcbinfo);
479 		return EINVAL;
480 	}
481 	INP_LOCK(inp);
482 	INP_INFO_RUNLOCK(&divcbinfo);
483 	socantsendmore(so);
484 	INP_UNLOCK(inp);
485 	return 0;
486 }
487 
488 static int
489 div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
490 	 struct mbuf *control, struct thread *td)
491 {
492 	/* Packet must have a header (but that's about it) */
493 	if (m->m_len < sizeof (struct ip) &&
494 	    (m = m_pullup(m, sizeof (struct ip))) == 0) {
495 		ipstat.ips_toosmall++;
496 		m_freem(m);
497 		return EINVAL;
498 	}
499 
500 	/* Send packet */
501 	return div_output(so, m, (struct sockaddr_in *)nam, control);
502 }
503 
504 void
505 div_ctlinput(int cmd, struct sockaddr *sa, void *vip)
506 {
507         struct in_addr faddr;
508 
509 	faddr = ((struct sockaddr_in *)sa)->sin_addr;
510 	if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
511         	return;
512 	if (PRC_IS_REDIRECT(cmd))
513 		return;
514 }
515 
516 static int
517 div_pcblist(SYSCTL_HANDLER_ARGS)
518 {
519 	int error, i, n;
520 	struct inpcb *inp, **inp_list;
521 	inp_gen_t gencnt;
522 	struct xinpgen xig;
523 
524 	/*
525 	 * The process of preparing the TCB list is too time-consuming and
526 	 * resource-intensive to repeat twice on every request.
527 	 */
528 	if (req->oldptr == 0) {
529 		n = divcbinfo.ipi_count;
530 		req->oldidx = 2 * (sizeof xig)
531 			+ (n + n/8) * sizeof(struct xinpcb);
532 		return 0;
533 	}
534 
535 	if (req->newptr != 0)
536 		return EPERM;
537 
538 	/*
539 	 * OK, now we're committed to doing something.
540 	 */
541 	INP_INFO_RLOCK(&divcbinfo);
542 	gencnt = divcbinfo.ipi_gencnt;
543 	n = divcbinfo.ipi_count;
544 	INP_INFO_RUNLOCK(&divcbinfo);
545 
546 	error = sysctl_wire_old_buffer(req,
547 	    2 * sizeof(xig) + n*sizeof(struct xinpcb));
548 	if (error != 0)
549 		return (error);
550 
551 	xig.xig_len = sizeof xig;
552 	xig.xig_count = n;
553 	xig.xig_gen = gencnt;
554 	xig.xig_sogen = so_gencnt;
555 	error = SYSCTL_OUT(req, &xig, sizeof xig);
556 	if (error)
557 		return error;
558 
559 	inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
560 	if (inp_list == 0)
561 		return ENOMEM;
562 
563 	INP_INFO_RLOCK(&divcbinfo);
564 	for (inp = LIST_FIRST(divcbinfo.listhead), i = 0; inp && i < n;
565 	     inp = LIST_NEXT(inp, inp_list)) {
566 		INP_LOCK(inp);
567 		if (inp->inp_gencnt <= gencnt &&
568 		    cr_canseesocket(req->td->td_ucred, inp->inp_socket) == 0)
569 			inp_list[i++] = inp;
570 		INP_UNLOCK(inp);
571 	}
572 	INP_INFO_RUNLOCK(&divcbinfo);
573 	n = i;
574 
575 	error = 0;
576 	for (i = 0; i < n; i++) {
577 		inp = inp_list[i];
578 		if (inp->inp_gencnt <= gencnt) {
579 			struct xinpcb xi;
580 			xi.xi_len = sizeof xi;
581 			/* XXX should avoid extra copy */
582 			bcopy(inp, &xi.xi_inp, sizeof *inp);
583 			if (inp->inp_socket)
584 				sotoxsocket(inp->inp_socket, &xi.xi_socket);
585 			error = SYSCTL_OUT(req, &xi, sizeof xi);
586 		}
587 	}
588 	if (!error) {
589 		/*
590 		 * Give the user an updated idea of our state.
591 		 * If the generation differs from what we told
592 		 * her before, she knows that something happened
593 		 * while we were processing this request, and it
594 		 * might be necessary to retry.
595 		 */
596 		INP_INFO_RLOCK(&divcbinfo);
597 		xig.xig_gen = divcbinfo.ipi_gencnt;
598 		xig.xig_sogen = so_gencnt;
599 		xig.xig_count = divcbinfo.ipi_count;
600 		INP_INFO_RUNLOCK(&divcbinfo);
601 		error = SYSCTL_OUT(req, &xig, sizeof xig);
602 	}
603 	free(inp_list, M_TEMP);
604 	return error;
605 }
606 
607 /*
608  * This is the wrapper function for in_setsockaddr.  We just pass down
609  * the pcbinfo for in_setpeeraddr to lock.
610  */
611 static int
612 div_sockaddr(struct socket *so, struct sockaddr **nam)
613 {
614 	return (in_setsockaddr(so, nam, &divcbinfo));
615 }
616 
617 /*
618  * This is the wrapper function for in_setpeeraddr. We just pass down
619  * the pcbinfo for in_setpeeraddr to lock.
620  */
621 static int
622 div_peeraddr(struct socket *so, struct sockaddr **nam)
623 {
624 	return (in_setpeeraddr(so, nam, &divcbinfo));
625 }
626 
627 #ifdef SYSCTL_NODE
628 SYSCTL_NODE(_net_inet, IPPROTO_DIVERT, divert, CTLFLAG_RW, 0, "IPDIVERT");
629 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, 0, 0,
630 	    div_pcblist, "S,xinpcb", "List of active divert sockets");
631 #endif
632 
633 struct pr_usrreqs div_usrreqs = {
634 	.pru_attach =		div_attach,
635 	.pru_bind =		div_bind,
636 	.pru_control =		in_control,
637 	.pru_detach =		div_detach,
638 	.pru_peeraddr =		div_peeraddr,
639 	.pru_send =		div_send,
640 	.pru_shutdown =		div_shutdown,
641 	.pru_sockaddr =		div_sockaddr,
642 	.pru_sosetlabel =	in_pcbsosetlabel
643 };
644 
645 struct protosw div_protosw = {
646   SOCK_RAW,	NULL,		IPPROTO_DIVERT,	PR_ATOMIC|PR_ADDR,
647   div_input,	NULL,		div_ctlinput,	ip_ctloutput,
648   NULL,
649   div_init,	NULL,		NULL,		NULL,
650   &div_usrreqs
651 };
652 
653 static int
654 div_modevent(module_t mod, int type, void *unused)
655 {
656 	int err = 0;
657 	int n;
658 
659 	switch (type) {
660 	case MOD_LOAD:
661 		/*
662 		 * Protocol will be initialized by pf_proto_register().
663 		 * We don't have to register ip_protox because we are not
664 		 * a true IP protocol that goes over the wire.
665 		 */
666 		err = pf_proto_register(PF_INET, &div_protosw);
667 		ip_divert_ptr = divert_packet;
668 		break;
669 	case MOD_QUIESCE:
670 		/*
671 		 * IPDIVERT may normally not be unloaded because of the
672 		 * potential race conditions.  Tell kldunload we can't be
673 		 * unloaded unless the unload is forced.
674 		 */
675 		err = EPERM;
676 		break;
677 	case MOD_UNLOAD:
678 		/*
679 		 * Forced unload.
680 		 *
681 		 * Module ipdivert can only be unloaded if no sockets are
682 		 * connected.  Maybe this can be changed later to forcefully
683 		 * disconnect any open sockets.
684 		 *
685 		 * XXXRW: Note that there is a slight race here, as a new
686 		 * socket open request could be spinning on the lock and then
687 		 * we destroy the lock.
688 		 */
689 		INP_INFO_WLOCK(&divcbinfo);
690 		n = divcbinfo.ipi_count;
691 		if (n != 0) {
692 			err = EBUSY;
693 			INP_INFO_WUNLOCK(&divcbinfo);
694 			break;
695 		}
696 		ip_divert_ptr = NULL;
697 		err = pf_proto_unregister(PF_INET, IPPROTO_DIVERT, SOCK_RAW);
698 		INP_INFO_WUNLOCK(&divcbinfo);
699 		INP_INFO_LOCK_DESTROY(&divcbinfo);
700 		uma_zdestroy(divcbinfo.ipi_zone);
701 		break;
702 	default:
703 		err = EOPNOTSUPP;
704 		break;
705 	}
706 	return err;
707 }
708 
709 static moduledata_t ipdivertmod = {
710         "ipdivert",
711         div_modevent,
712         0
713 };
714 
715 DECLARE_MODULE(ipdivert, ipdivertmod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
716 MODULE_DEPEND(dummynet, ipfw, 2, 2, 2);
717 MODULE_VERSION(ipdivert, 1);
718