xref: /freebsd/sys/net/if.c (revision 06064893b3c62c648518be78604fac29fc0d9d61)
1 /*
2  * Copyright (c) 1980, 1986, 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  *	@(#)if.c	8.5 (Berkeley) 1/9/95
30  * $FreeBSD$
31  */
32 
33 #include "opt_compat.h"
34 #include "opt_inet6.h"
35 #include "opt_inet.h"
36 #include "opt_mac.h"
37 
38 #include <sys/param.h>
39 #include <sys/types.h>
40 #include <sys/conf.h>
41 #include <sys/mac.h>
42 #include <sys/malloc.h>
43 #include <sys/sbuf.h>
44 #include <sys/bus.h>
45 #include <sys/mbuf.h>
46 #include <sys/systm.h>
47 #include <sys/proc.h>
48 #include <sys/socket.h>
49 #include <sys/socketvar.h>
50 #include <sys/protosw.h>
51 #include <sys/kernel.h>
52 #include <sys/sockio.h>
53 #include <sys/syslog.h>
54 #include <sys/sysctl.h>
55 #include <sys/taskqueue.h>
56 #include <sys/domain.h>
57 #include <sys/jail.h>
58 #include <machine/stdarg.h>
59 
60 #include <net/if.h>
61 #include <net/if_arp.h>
62 #include <net/if_clone.h>
63 #include <net/if_dl.h>
64 #include <net/if_types.h>
65 #include <net/if_var.h>
66 #include <net/radix.h>
67 #include <net/route.h>
68 
69 #if defined(INET) || defined(INET6)
70 /*XXX*/
71 #include <netinet/in.h>
72 #include <netinet/in_var.h>
73 #ifdef INET6
74 #include <netinet6/in6_var.h>
75 #include <netinet6/in6_ifattach.h>
76 #endif
77 #endif
78 #ifdef INET
79 #include <netinet/if_ether.h>
80 #endif
81 
82 struct mbuf *(*tbr_dequeue_ptr)(struct ifaltq *, int) = NULL;
83 
84 static void	if_attachdomain(void *);
85 static void	if_attachdomain1(struct ifnet *);
86 static int	ifconf(u_long, caddr_t);
87 static void	if_grow(void);
88 static void	if_init(void *);
89 static void	if_check(void *);
90 static int	if_findindex(struct ifnet *);
91 static void	if_qflush(struct ifaltq *);
92 static void	if_route(struct ifnet *, int flag, int fam);
93 static void	if_slowtimo(void *);
94 static void	if_unroute(struct ifnet *, int flag, int fam);
95 static void	link_rtrequest(int, struct rtentry *, struct rt_addrinfo *);
96 static int	if_rtdel(struct radix_node *, void *);
97 static int	ifhwioctl(u_long, struct ifnet *, caddr_t, struct thread *);
98 static void	if_start_deferred(void *context, int pending);
99 #ifdef INET6
100 /*
101  * XXX: declare here to avoid to include many inet6 related files..
102  * should be more generalized?
103  */
104 extern void	nd6_setmtu(struct ifnet *);
105 #endif
106 
107 int	if_index = 0;
108 struct	ifindex_entry *ifindex_table = NULL;
109 int	ifqmaxlen = IFQ_MAXLEN;
110 struct	ifnethead ifnet;	/* depend on static init XXX */
111 struct	mtx ifnet_lock;
112 
113 static int	if_indexlim = 8;
114 static struct	knlist ifklist;
115 
116 static void	filt_netdetach(struct knote *kn);
117 static int	filt_netdev(struct knote *kn, long hint);
118 
119 static struct filterops netdev_filtops =
120     { 1, NULL, filt_netdetach, filt_netdev };
121 
122 /*
123  * System initialization
124  */
125 SYSINIT(interfaces, SI_SUB_INIT_IF, SI_ORDER_FIRST, if_init, NULL)
126 SYSINIT(interface_check, SI_SUB_PROTO_IF, SI_ORDER_FIRST, if_check, NULL)
127 
128 MALLOC_DEFINE(M_IFADDR, "ifaddr", "interface address");
129 MALLOC_DEFINE(M_IFMADDR, "ether_multi", "link-level multicast address");
130 
131 static d_open_t		netopen;
132 static d_close_t	netclose;
133 static d_ioctl_t	netioctl;
134 static d_kqfilter_t	netkqfilter;
135 
136 static struct cdevsw net_cdevsw = {
137 	.d_version =	D_VERSION,
138 	.d_flags =	D_NEEDGIANT,
139 	.d_open =	netopen,
140 	.d_close =	netclose,
141 	.d_ioctl =	netioctl,
142 	.d_name =	"net",
143 	.d_kqfilter =	netkqfilter,
144 };
145 
146 static int
147 netopen(struct cdev *dev, int flag, int mode, struct thread *td)
148 {
149 	return (0);
150 }
151 
152 static int
153 netclose(struct cdev *dev, int flags, int fmt, struct thread *td)
154 {
155 	return (0);
156 }
157 
158 static int
159 netioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag, struct thread *td)
160 {
161 	struct ifnet *ifp;
162 	int error, idx;
163 
164 	/* only support interface specific ioctls */
165 	if (IOCGROUP(cmd) != 'i')
166 		return (EOPNOTSUPP);
167 	idx = minor(dev);
168 	if (idx == 0) {
169 		/*
170 		 * special network device, not interface.
171 		 */
172 		if (cmd == SIOCGIFCONF)
173 			return (ifconf(cmd, data));	/* XXX remove cmd */
174 		return (EOPNOTSUPP);
175 	}
176 
177 	ifp = ifnet_byindex(idx);
178 	if (ifp == NULL)
179 		return (ENXIO);
180 
181 	error = ifhwioctl(cmd, ifp, data, td);
182 	if (error == ENOIOCTL)
183 		error = EOPNOTSUPP;
184 	return (error);
185 }
186 
187 static int
188 netkqfilter(struct cdev *dev, struct knote *kn)
189 {
190 	struct knlist *klist;
191 	struct ifnet *ifp;
192 	int idx;
193 
194 	switch (kn->kn_filter) {
195 	case EVFILT_NETDEV:
196 		kn->kn_fop = &netdev_filtops;
197 		break;
198 	default:
199 		return (1);
200 	}
201 
202 	idx = minor(dev);
203 	if (idx == 0) {
204 		klist = &ifklist;
205 	} else {
206 		ifp = ifnet_byindex(idx);
207 		if (ifp == NULL)
208 			return (1);
209 		klist = &ifp->if_klist;
210 	}
211 
212 	kn->kn_hook = (caddr_t)klist;
213 
214 	knlist_add(klist, kn, 0);
215 
216 	return (0);
217 }
218 
219 static void
220 filt_netdetach(struct knote *kn)
221 {
222 	struct knlist *klist = (struct knlist *)kn->kn_hook;
223 
224 	knlist_remove(klist, kn, 0);
225 }
226 
227 static int
228 filt_netdev(struct knote *kn, long hint)
229 {
230 	struct knlist *klist = (struct knlist *)kn->kn_hook;
231 
232 	/*
233 	 * Currently NOTE_EXIT is abused to indicate device detach.
234 	 */
235 	if (hint == NOTE_EXIT) {
236 		kn->kn_data = NOTE_LINKINV;
237 		kn->kn_flags |= (EV_EOF | EV_ONESHOT);
238 		knlist_remove_inevent(klist, kn);
239 		return (1);
240 	}
241 	if (hint != 0)
242 		kn->kn_data = hint;			/* current status */
243 	if (kn->kn_sfflags & hint)
244 		kn->kn_fflags |= hint;
245 	return (kn->kn_fflags != 0);
246 }
247 
248 /*
249  * Network interface utility routines.
250  *
251  * Routines with ifa_ifwith* names take sockaddr *'s as
252  * parameters.
253  */
254 /* ARGSUSED*/
255 static void
256 if_init(void *dummy __unused)
257 {
258 
259 	IFNET_LOCK_INIT();
260 	TAILQ_INIT(&ifnet);
261 	knlist_init(&ifklist, NULL);
262 	if_grow();				/* create initial table */
263 	ifdev_byindex(0) = make_dev(&net_cdevsw, 0,
264 	    UID_ROOT, GID_WHEEL, 0600, "network");
265 	if_clone_init();
266 }
267 
268 static void
269 if_grow(void)
270 {
271 	u_int n;
272 	struct ifindex_entry *e;
273 
274 	if_indexlim <<= 1;
275 	n = if_indexlim * sizeof(*e);
276 	e = malloc(n, M_IFADDR, M_WAITOK | M_ZERO);
277 	if (ifindex_table != NULL) {
278 		memcpy((caddr_t)e, (caddr_t)ifindex_table, n/2);
279 		free((caddr_t)ifindex_table, M_IFADDR);
280 	}
281 	ifindex_table = e;
282 }
283 
284 /* ARGSUSED*/
285 static void
286 if_check(void *dummy __unused)
287 {
288 	struct ifnet *ifp;
289 	int s;
290 
291 	s = splimp();
292 	IFNET_RLOCK();	/* could sleep on rare error; mostly okay XXX */
293 	TAILQ_FOREACH(ifp, &ifnet, if_link) {
294 		if (ifp->if_snd.ifq_maxlen == 0) {
295 			if_printf(ifp, "XXX: driver didn't set ifq_maxlen\n");
296 			ifp->if_snd.ifq_maxlen = ifqmaxlen;
297 		}
298 		if (!mtx_initialized(&ifp->if_snd.ifq_mtx)) {
299 			if_printf(ifp,
300 			    "XXX: driver didn't initialize queue mtx\n");
301 			mtx_init(&ifp->if_snd.ifq_mtx, "unknown",
302 			    MTX_NETWORK_LOCK, MTX_DEF);
303 		}
304 	}
305 	IFNET_RUNLOCK();
306 	splx(s);
307 	if_slowtimo(0);
308 }
309 
310 static int
311 if_findindex(struct ifnet *ifp)
312 {
313 	int i, unit;
314 	char eaddr[18], devname[32];
315 	const char *name, *p;
316 
317 	switch (ifp->if_type) {
318 	case IFT_ETHER:			/* these types use struct arpcom */
319 	case IFT_FDDI:
320 	case IFT_XETHER:
321 	case IFT_ISO88025:
322 	case IFT_L2VLAN:
323 		snprintf(eaddr, 18, "%6D", IFP2AC(ifp)->ac_enaddr, ":");
324 		break;
325 	default:
326 		eaddr[0] = '\0';
327 		break;
328 	}
329 	strlcpy(devname, ifp->if_xname, sizeof(devname));
330 	name = net_cdevsw.d_name;
331 	i = 0;
332 	while ((resource_find_dev(&i, name, &unit, NULL, NULL)) == 0) {
333 		if (resource_string_value(name, unit, "ether", &p) == 0)
334 			if (strcmp(p, eaddr) == 0)
335 				goto found;
336 		if (resource_string_value(name, unit, "dev", &p) == 0)
337 			if (strcmp(p, devname) == 0)
338 				goto found;
339 	}
340 	unit = 0;
341 found:
342 	if (unit != 0) {
343 		if (ifaddr_byindex(unit) == NULL)
344 			return (unit);
345 		printf("%s%d in use, cannot hardwire it to %s.\n",
346 		    name, unit, devname);
347 	}
348 	for (unit = 1; ; unit++) {
349 		if (unit <= if_index && ifaddr_byindex(unit) != NULL)
350 			continue;
351 		if (resource_string_value(name, unit, "ether", &p) == 0 ||
352 		    resource_string_value(name, unit, "dev", &p) == 0)
353 			continue;
354 		break;
355 	}
356 	return (unit);
357 }
358 
359 /*
360  * Attach an interface to the
361  * list of "active" interfaces.
362  */
363 void
364 if_attach(struct ifnet *ifp)
365 {
366 	unsigned socksize, ifasize;
367 	int namelen, masklen;
368 	struct sockaddr_dl *sdl;
369 	struct ifaddr *ifa;
370 
371 	TASK_INIT(&ifp->if_starttask, 0, if_start_deferred, ifp);
372 	IF_AFDATA_LOCK_INIT(ifp);
373 	ifp->if_afdata_initialized = 0;
374 	IFNET_WLOCK();
375 	TAILQ_INSERT_TAIL(&ifnet, ifp, if_link);
376 	IFNET_WUNLOCK();
377 	/*
378 	 * XXX -
379 	 * The old code would work if the interface passed a pre-existing
380 	 * chain of ifaddrs to this code.  We don't trust our callers to
381 	 * properly initialize the tailq, however, so we no longer allow
382 	 * this unlikely case.
383 	 */
384 	TAILQ_INIT(&ifp->if_addrhead);
385 	TAILQ_INIT(&ifp->if_prefixhead);
386 	TAILQ_INIT(&ifp->if_multiaddrs);
387 	knlist_init(&ifp->if_klist, NULL);
388 	getmicrotime(&ifp->if_lastchange);
389 	ifp->if_data.ifi_epoch = time_second;
390 
391 #ifdef MAC
392 	mac_init_ifnet(ifp);
393 	mac_create_ifnet(ifp);
394 #endif
395 
396 	ifp->if_index = if_findindex(ifp);
397 	if (ifp->if_index > if_index)
398 		if_index = ifp->if_index;
399 	if (if_index >= if_indexlim)
400 		if_grow();
401 	ifp->if_data.ifi_datalen = sizeof(struct if_data);
402 
403 	ifnet_byindex(ifp->if_index) = ifp;
404 	ifdev_byindex(ifp->if_index) = make_dev(&net_cdevsw,
405 	    unit2minor(ifp->if_index),
406 	    UID_ROOT, GID_WHEEL, 0600, "%s/%s",
407 	    net_cdevsw.d_name, ifp->if_xname);
408 	make_dev_alias(ifdev_byindex(ifp->if_index), "%s%d",
409 	    net_cdevsw.d_name, ifp->if_index);
410 
411 	mtx_init(&ifp->if_snd.ifq_mtx, ifp->if_xname, "if send queue", MTX_DEF);
412 
413 	/*
414 	 * create a Link Level name for this device
415 	 */
416 	namelen = strlen(ifp->if_xname);
417 	/*
418 	 * Always save enough space for any possiable name so we can do
419 	 * a rename in place later.
420 	 */
421 	masklen = offsetof(struct sockaddr_dl, sdl_data[0]) + IFNAMSIZ;
422 	socksize = masklen + ifp->if_addrlen;
423 	if (socksize < sizeof(*sdl))
424 		socksize = sizeof(*sdl);
425 	socksize = roundup2(socksize, sizeof(long));
426 	ifasize = sizeof(*ifa) + 2 * socksize;
427 	ifa = malloc(ifasize, M_IFADDR, M_WAITOK | M_ZERO);
428 	IFA_LOCK_INIT(ifa);
429 	sdl = (struct sockaddr_dl *)(ifa + 1);
430 	sdl->sdl_len = socksize;
431 	sdl->sdl_family = AF_LINK;
432 	bcopy(ifp->if_xname, sdl->sdl_data, namelen);
433 	sdl->sdl_nlen = namelen;
434 	sdl->sdl_index = ifp->if_index;
435 	sdl->sdl_type = ifp->if_type;
436 	ifaddr_byindex(ifp->if_index) = ifa;
437 	ifa->ifa_ifp = ifp;
438 	ifa->ifa_rtrequest = link_rtrequest;
439 	ifa->ifa_addr = (struct sockaddr *)sdl;
440 	sdl = (struct sockaddr_dl *)(socksize + (caddr_t)sdl);
441 	ifa->ifa_netmask = (struct sockaddr *)sdl;
442 	sdl->sdl_len = masklen;
443 	while (namelen != 0)
444 		sdl->sdl_data[--namelen] = 0xff;
445 	ifa->ifa_refcnt = 1;
446 	TAILQ_INSERT_HEAD(&ifp->if_addrhead, ifa, ifa_link);
447 	ifp->if_broadcastaddr = NULL; /* reliably crash if used uninitialized */
448 	ifp->if_snd.altq_type = 0;
449 	ifp->if_snd.altq_disc = NULL;
450 	ifp->if_snd.altq_flags &= ALTQF_CANTCHANGE;
451 	ifp->if_snd.altq_tbr  = NULL;
452 	ifp->if_snd.altq_ifp  = ifp;
453 
454 	if (domain_init_status >= 2)
455 		if_attachdomain1(ifp);
456 
457 	EVENTHANDLER_INVOKE(ifnet_arrival_event, ifp);
458 
459 	/* Announce the interface. */
460 	rt_ifannouncemsg(ifp, IFAN_ARRIVAL);
461 }
462 
463 static void
464 if_attachdomain(void *dummy)
465 {
466 	struct ifnet *ifp;
467 	int s;
468 
469 	s = splnet();
470 	TAILQ_FOREACH(ifp, &ifnet, if_link)
471 		if_attachdomain1(ifp);
472 	splx(s);
473 }
474 SYSINIT(domainifattach, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_SECOND,
475     if_attachdomain, NULL);
476 
477 static void
478 if_attachdomain1(struct ifnet *ifp)
479 {
480 	struct domain *dp;
481 	int s;
482 
483 	s = splnet();
484 
485 	/*
486 	 * Since dp->dom_ifattach calls malloc() with M_WAITOK, we
487 	 * cannot lock ifp->if_afdata initialization, entirely.
488 	 */
489 	if (IF_AFDATA_TRYLOCK(ifp) == 0) {
490 		splx(s);
491 		return;
492 	}
493 	if (ifp->if_afdata_initialized >= domain_init_status) {
494 		IF_AFDATA_UNLOCK(ifp);
495 		splx(s);
496 		printf("if_attachdomain called more than once on %s\n",
497 		    ifp->if_xname);
498 		return;
499 	}
500 	ifp->if_afdata_initialized = domain_init_status;
501 	IF_AFDATA_UNLOCK(ifp);
502 
503 	/* address family dependent data region */
504 	bzero(ifp->if_afdata, sizeof(ifp->if_afdata));
505 	for (dp = domains; dp; dp = dp->dom_next) {
506 		if (dp->dom_ifattach)
507 			ifp->if_afdata[dp->dom_family] =
508 			    (*dp->dom_ifattach)(ifp);
509 	}
510 
511 	splx(s);
512 }
513 
514 /*
515  * Detach an interface, removing it from the
516  * list of "active" interfaces.
517  */
518 void
519 if_detach(struct ifnet *ifp)
520 {
521 	struct ifaddr *ifa, *next;
522 	struct radix_node_head	*rnh;
523 	int s;
524 	int i;
525 	struct domain *dp;
526  	struct ifnet *iter;
527  	int found;
528 
529 	EVENTHANDLER_INVOKE(ifnet_departure_event, ifp);
530 	/*
531 	 * Remove routes and flush queues.
532 	 */
533 	s = splnet();
534 	if_down(ifp);
535 #ifdef ALTQ
536 	if (ALTQ_IS_ENABLED(&ifp->if_snd))
537 		altq_disable(&ifp->if_snd);
538 	if (ALTQ_IS_ATTACHED(&ifp->if_snd))
539 		altq_detach(&ifp->if_snd);
540 #endif
541 
542 	for (ifa = TAILQ_FIRST(&ifp->if_addrhead); ifa; ifa = next) {
543 		next = TAILQ_NEXT(ifa, ifa_link);
544 
545 		if (ifa->ifa_addr->sa_family == AF_LINK)
546 			continue;
547 #ifdef INET
548 		/* XXX: Ugly!! ad hoc just for INET */
549 		if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) {
550 			struct ifaliasreq ifr;
551 
552 			bzero(&ifr, sizeof(ifr));
553 			ifr.ifra_addr = *ifa->ifa_addr;
554 			if (ifa->ifa_dstaddr)
555 				ifr.ifra_broadaddr = *ifa->ifa_dstaddr;
556 			if (in_control(NULL, SIOCDIFADDR, (caddr_t)&ifr, ifp,
557 			    NULL) == 0)
558 				continue;
559 		}
560 #endif /* INET */
561 #ifdef INET6
562 		if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET6) {
563 			in6_purgeaddr(ifa);
564 			/* ifp_addrhead is already updated */
565 			continue;
566 		}
567 #endif /* INET6 */
568 		TAILQ_REMOVE(&ifp->if_addrhead, ifa, ifa_link);
569 		IFAFREE(ifa);
570 	}
571 
572 #ifdef INET6
573 	/*
574 	 * Remove all IPv6 kernel structs related to ifp.  This should be done
575 	 * before removing routing entries below, since IPv6 interface direct
576 	 * routes are expected to be removed by the IPv6-specific kernel API.
577 	 * Otherwise, the kernel will detect some inconsistency and bark it.
578 	 */
579 	in6_ifdetach(ifp);
580 #endif
581 	/*
582 	 * Remove address from ifindex_table[] and maybe decrement if_index.
583 	 * Clean up all addresses.
584 	 */
585 	ifnet_byindex(ifp->if_index) = NULL;
586 	ifaddr_byindex(ifp->if_index) = NULL;
587 	destroy_dev(ifdev_byindex(ifp->if_index));
588 	ifdev_byindex(ifp->if_index) = NULL;
589 
590 	while (if_index > 0 && ifaddr_byindex(if_index) == NULL)
591 		if_index--;
592 
593 
594 	/* We can now free link ifaddr. */
595 	if (!TAILQ_EMPTY(&ifp->if_addrhead)) {
596 		ifa = TAILQ_FIRST(&ifp->if_addrhead);
597 		TAILQ_REMOVE(&ifp->if_addrhead, ifa, ifa_link);
598 		IFAFREE(ifa);
599 	}
600 
601 	/*
602 	 * Delete all remaining routes using this interface
603 	 * Unfortuneatly the only way to do this is to slog through
604 	 * the entire routing table looking for routes which point
605 	 * to this interface...oh well...
606 	 */
607 	for (i = 1; i <= AF_MAX; i++) {
608 		if ((rnh = rt_tables[i]) == NULL)
609 			continue;
610 		RADIX_NODE_HEAD_LOCK(rnh);
611 		(void) rnh->rnh_walktree(rnh, if_rtdel, ifp);
612 		RADIX_NODE_HEAD_UNLOCK(rnh);
613 	}
614 
615 	/* Announce that the interface is gone. */
616 	rt_ifannouncemsg(ifp, IFAN_DEPARTURE);
617 
618 	IF_AFDATA_LOCK(ifp);
619 	for (dp = domains; dp; dp = dp->dom_next) {
620 		if (dp->dom_ifdetach && ifp->if_afdata[dp->dom_family])
621 			(*dp->dom_ifdetach)(ifp,
622 			    ifp->if_afdata[dp->dom_family]);
623 	}
624 	IF_AFDATA_UNLOCK(ifp);
625 
626 #ifdef MAC
627 	mac_destroy_ifnet(ifp);
628 #endif /* MAC */
629 	KNOTE_UNLOCKED(&ifp->if_klist, NOTE_EXIT);
630 	knlist_clear(&ifp->if_klist, 0);
631 	knlist_destroy(&ifp->if_klist);
632 	IFNET_WLOCK();
633  	found = 0;
634  	TAILQ_FOREACH(iter, &ifnet, if_link)
635  		if (iter == ifp) {
636  			found = 1;
637  			break;
638  		}
639  	if (found)
640  		TAILQ_REMOVE(&ifnet, ifp, if_link);
641 	IFNET_WUNLOCK();
642 	mtx_destroy(&ifp->if_snd.ifq_mtx);
643 	IF_AFDATA_DESTROY(ifp);
644 	splx(s);
645 }
646 
647 /*
648  * Delete Routes for a Network Interface
649  *
650  * Called for each routing entry via the rnh->rnh_walktree() call above
651  * to delete all route entries referencing a detaching network interface.
652  *
653  * Arguments:
654  *	rn	pointer to node in the routing table
655  *	arg	argument passed to rnh->rnh_walktree() - detaching interface
656  *
657  * Returns:
658  *	0	successful
659  *	errno	failed - reason indicated
660  *
661  */
662 static int
663 if_rtdel(struct radix_node *rn, void *arg)
664 {
665 	struct rtentry	*rt = (struct rtentry *)rn;
666 	struct ifnet	*ifp = arg;
667 	int		err;
668 
669 	if (rt->rt_ifp == ifp) {
670 
671 		/*
672 		 * Protect (sorta) against walktree recursion problems
673 		 * with cloned routes
674 		 */
675 		if ((rt->rt_flags & RTF_UP) == 0)
676 			return (0);
677 
678 		err = rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
679 				rt_mask(rt), rt->rt_flags,
680 				(struct rtentry **) NULL);
681 		if (err) {
682 			log(LOG_WARNING, "if_rtdel: error %d\n", err);
683 		}
684 	}
685 
686 	return (0);
687 }
688 
689 #define	equal(a1, a2)	(bcmp((a1), (a2), ((a1))->sa_len) == 0)
690 
691 /*
692  * Locate an interface based on a complete address.
693  */
694 /*ARGSUSED*/
695 struct ifaddr *
696 ifa_ifwithaddr(struct sockaddr *addr)
697 {
698 	struct ifnet *ifp;
699 	struct ifaddr *ifa;
700 
701 	IFNET_RLOCK();
702 	TAILQ_FOREACH(ifp, &ifnet, if_link)
703 		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
704 			if (ifa->ifa_addr->sa_family != addr->sa_family)
705 				continue;
706 			if (equal(addr, ifa->ifa_addr))
707 				goto done;
708 			/* IP6 doesn't have broadcast */
709 			if ((ifp->if_flags & IFF_BROADCAST) &&
710 			    ifa->ifa_broadaddr &&
711 			    ifa->ifa_broadaddr->sa_len != 0 &&
712 			    equal(ifa->ifa_broadaddr, addr))
713 				goto done;
714 		}
715 	ifa = NULL;
716 done:
717 	IFNET_RUNLOCK();
718 	return (ifa);
719 }
720 
721 /*
722  * Locate the point to point interface with a given destination address.
723  */
724 /*ARGSUSED*/
725 struct ifaddr *
726 ifa_ifwithdstaddr(struct sockaddr *addr)
727 {
728 	struct ifnet *ifp;
729 	struct ifaddr *ifa;
730 
731 	IFNET_RLOCK();
732 	TAILQ_FOREACH(ifp, &ifnet, if_link) {
733 		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
734 			continue;
735 		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
736 			if (ifa->ifa_addr->sa_family != addr->sa_family)
737 				continue;
738 			if (ifa->ifa_dstaddr && equal(addr, ifa->ifa_dstaddr))
739 				goto done;
740 		}
741 	}
742 	ifa = NULL;
743 done:
744 	IFNET_RUNLOCK();
745 	return (ifa);
746 }
747 
748 /*
749  * Find an interface on a specific network.  If many, choice
750  * is most specific found.
751  */
752 struct ifaddr *
753 ifa_ifwithnet(struct sockaddr *addr)
754 {
755 	struct ifnet *ifp;
756 	struct ifaddr *ifa;
757 	struct ifaddr *ifa_maybe = (struct ifaddr *) 0;
758 	u_int af = addr->sa_family;
759 	char *addr_data = addr->sa_data, *cplim;
760 
761 	/*
762 	 * AF_LINK addresses can be looked up directly by their index number,
763 	 * so do that if we can.
764 	 */
765 	if (af == AF_LINK) {
766 	    struct sockaddr_dl *sdl = (struct sockaddr_dl *)addr;
767 	    if (sdl->sdl_index && sdl->sdl_index <= if_index)
768 		return (ifaddr_byindex(sdl->sdl_index));
769 	}
770 
771 	/*
772 	 * Scan though each interface, looking for ones that have
773 	 * addresses in this address family.
774 	 */
775 	IFNET_RLOCK();
776 	TAILQ_FOREACH(ifp, &ifnet, if_link) {
777 		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
778 			char *cp, *cp2, *cp3;
779 
780 			if (ifa->ifa_addr->sa_family != af)
781 next:				continue;
782 			if (af == AF_INET && ifp->if_flags & IFF_POINTOPOINT) {
783 				/*
784 				 * This is a bit broken as it doesn't
785 				 * take into account that the remote end may
786 				 * be a single node in the network we are
787 				 * looking for.
788 				 * The trouble is that we don't know the
789 				 * netmask for the remote end.
790 				 */
791 				if (ifa->ifa_dstaddr != 0
792 				    && equal(addr, ifa->ifa_dstaddr))
793 					goto done;
794 			} else {
795 				/*
796 				 * if we have a special address handler,
797 				 * then use it instead of the generic one.
798 				 */
799 				if (ifa->ifa_claim_addr) {
800 					if ((*ifa->ifa_claim_addr)(ifa, addr))
801 						goto done;
802 					continue;
803 				}
804 
805 				/*
806 				 * Scan all the bits in the ifa's address.
807 				 * If a bit dissagrees with what we are
808 				 * looking for, mask it with the netmask
809 				 * to see if it really matters.
810 				 * (A byte at a time)
811 				 */
812 				if (ifa->ifa_netmask == 0)
813 					continue;
814 				cp = addr_data;
815 				cp2 = ifa->ifa_addr->sa_data;
816 				cp3 = ifa->ifa_netmask->sa_data;
817 				cplim = ifa->ifa_netmask->sa_len
818 					+ (char *)ifa->ifa_netmask;
819 				while (cp3 < cplim)
820 					if ((*cp++ ^ *cp2++) & *cp3++)
821 						goto next; /* next address! */
822 				/*
823 				 * If the netmask of what we just found
824 				 * is more specific than what we had before
825 				 * (if we had one) then remember the new one
826 				 * before continuing to search
827 				 * for an even better one.
828 				 */
829 				if (ifa_maybe == 0 ||
830 				    rn_refines((caddr_t)ifa->ifa_netmask,
831 				    (caddr_t)ifa_maybe->ifa_netmask))
832 					ifa_maybe = ifa;
833 			}
834 		}
835 	}
836 	ifa = ifa_maybe;
837 done:
838 	IFNET_RUNLOCK();
839 	return (ifa);
840 }
841 
842 /*
843  * Find an interface address specific to an interface best matching
844  * a given address.
845  */
846 struct ifaddr *
847 ifaof_ifpforaddr(struct sockaddr *addr, struct ifnet *ifp)
848 {
849 	struct ifaddr *ifa;
850 	char *cp, *cp2, *cp3;
851 	char *cplim;
852 	struct ifaddr *ifa_maybe = 0;
853 	u_int af = addr->sa_family;
854 
855 	if (af >= AF_MAX)
856 		return (0);
857 	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
858 		if (ifa->ifa_addr->sa_family != af)
859 			continue;
860 		if (ifa_maybe == 0)
861 			ifa_maybe = ifa;
862 		if (ifa->ifa_netmask == 0) {
863 			if (equal(addr, ifa->ifa_addr) ||
864 			    (ifa->ifa_dstaddr && equal(addr, ifa->ifa_dstaddr)))
865 				goto done;
866 			continue;
867 		}
868 		if (ifp->if_flags & IFF_POINTOPOINT) {
869 			if (equal(addr, ifa->ifa_dstaddr))
870 				goto done;
871 		} else {
872 			cp = addr->sa_data;
873 			cp2 = ifa->ifa_addr->sa_data;
874 			cp3 = ifa->ifa_netmask->sa_data;
875 			cplim = ifa->ifa_netmask->sa_len + (char *)ifa->ifa_netmask;
876 			for (; cp3 < cplim; cp3++)
877 				if ((*cp++ ^ *cp2++) & *cp3)
878 					break;
879 			if (cp3 == cplim)
880 				goto done;
881 		}
882 	}
883 	ifa = ifa_maybe;
884 done:
885 	return (ifa);
886 }
887 
888 #include <net/route.h>
889 
890 /*
891  * Default action when installing a route with a Link Level gateway.
892  * Lookup an appropriate real ifa to point to.
893  * This should be moved to /sys/net/link.c eventually.
894  */
895 static void
896 link_rtrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
897 {
898 	struct ifaddr *ifa, *oifa;
899 	struct sockaddr *dst;
900 	struct ifnet *ifp;
901 
902 	RT_LOCK_ASSERT(rt);
903 
904 	if (cmd != RTM_ADD || ((ifa = rt->rt_ifa) == 0) ||
905 	    ((ifp = ifa->ifa_ifp) == 0) || ((dst = rt_key(rt)) == 0))
906 		return;
907 	ifa = ifaof_ifpforaddr(dst, ifp);
908 	if (ifa) {
909 		IFAREF(ifa);		/* XXX */
910 		oifa = rt->rt_ifa;
911 		rt->rt_ifa = ifa;
912 		IFAFREE(oifa);
913 		if (ifa->ifa_rtrequest && ifa->ifa_rtrequest != link_rtrequest)
914 			ifa->ifa_rtrequest(cmd, rt, info);
915 	}
916 }
917 
918 /*
919  * Mark an interface down and notify protocols of
920  * the transition.
921  * NOTE: must be called at splnet or eqivalent.
922  */
923 static void
924 if_unroute(struct ifnet *ifp, int flag, int fam)
925 {
926 	struct ifaddr *ifa;
927 
928 	ifp->if_flags &= ~flag;
929 	getmicrotime(&ifp->if_lastchange);
930 	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
931 		if (fam == PF_UNSPEC || (fam == ifa->ifa_addr->sa_family))
932 			pfctlinput(PRC_IFDOWN, ifa->ifa_addr);
933 	if_qflush(&ifp->if_snd);
934 	rt_ifmsg(ifp);
935 }
936 
937 /*
938  * Mark an interface up and notify protocols of
939  * the transition.
940  * NOTE: must be called at splnet or eqivalent.
941  */
942 static void
943 if_route(struct ifnet *ifp, int flag, int fam)
944 {
945 	struct ifaddr *ifa;
946 
947 	ifp->if_flags |= flag;
948 	getmicrotime(&ifp->if_lastchange);
949 	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
950 		if (fam == PF_UNSPEC || (fam == ifa->ifa_addr->sa_family))
951 			pfctlinput(PRC_IFUP, ifa->ifa_addr);
952 	rt_ifmsg(ifp);
953 #ifdef INET6
954 	in6_if_up(ifp);
955 #endif
956 }
957 
958 void	(*vlan_link_state_p)(struct ifnet *, int);	/* XXX: private from if_vlan */
959 
960 /*
961  * Handle a change in the interface link state.
962  */
963 void
964 if_link_state_change(struct ifnet *ifp, int link_state)
965 {
966 	int link;
967 
968 	/* Notify that the link state has changed. */
969 	if (ifp->if_link_state != link_state) {
970 		ifp->if_link_state = link_state;
971 		rt_ifmsg(ifp);
972 		if (link_state == LINK_STATE_UP)
973 			link = NOTE_LINKUP;
974 		else if (link_state == LINK_STATE_DOWN)
975 			link = NOTE_LINKDOWN;
976 		else
977 			link = NOTE_LINKINV;
978 		KNOTE_UNLOCKED(&ifp->if_klist, link);
979 		if (ifp->if_nvlans != 0)
980 			(*vlan_link_state_p)(ifp, link);
981 	}
982 }
983 
984 /*
985  * Mark an interface down and notify protocols of
986  * the transition.
987  * NOTE: must be called at splnet or eqivalent.
988  */
989 void
990 if_down(struct ifnet *ifp)
991 {
992 
993 	if_unroute(ifp, IFF_UP, AF_UNSPEC);
994 }
995 
996 /*
997  * Mark an interface up and notify protocols of
998  * the transition.
999  * NOTE: must be called at splnet or eqivalent.
1000  */
1001 void
1002 if_up(struct ifnet *ifp)
1003 {
1004 
1005 	if_route(ifp, IFF_UP, AF_UNSPEC);
1006 }
1007 
1008 /*
1009  * Flush an interface queue.
1010  */
1011 static void
1012 if_qflush(struct ifaltq *ifq)
1013 {
1014 	struct mbuf *m, *n;
1015 
1016 	IFQ_LOCK(ifq);
1017 #ifdef ALTQ
1018 	if (ALTQ_IS_ENABLED(ifq))
1019 		ALTQ_PURGE(ifq);
1020 #endif
1021 	n = ifq->ifq_head;
1022 	while ((m = n) != 0) {
1023 		n = m->m_act;
1024 		m_freem(m);
1025 	}
1026 	ifq->ifq_head = 0;
1027 	ifq->ifq_tail = 0;
1028 	ifq->ifq_len = 0;
1029 	IFQ_UNLOCK(ifq);
1030 }
1031 
1032 /*
1033  * Handle interface watchdog timer routines.  Called
1034  * from softclock, we decrement timers (if set) and
1035  * call the appropriate interface routine on expiration.
1036  *
1037  * XXXRW: Note that because timeouts run with Giant, if_watchdog() is called
1038  * holding Giant.  If we switch to an MPSAFE callout, we likely need to grab
1039  * Giant before entering if_watchdog() on an IFF_NEEDSGIANT interface.
1040  */
1041 static void
1042 if_slowtimo(void *arg)
1043 {
1044 	struct ifnet *ifp;
1045 	int s = splimp();
1046 
1047 	IFNET_RLOCK();
1048 	TAILQ_FOREACH(ifp, &ifnet, if_link) {
1049 		if (ifp->if_timer == 0 || --ifp->if_timer)
1050 			continue;
1051 		if (ifp->if_watchdog)
1052 			(*ifp->if_watchdog)(ifp);
1053 	}
1054 	IFNET_RUNLOCK();
1055 	splx(s);
1056 	timeout(if_slowtimo, (void *)0, hz / IFNET_SLOWHZ);
1057 }
1058 
1059 /*
1060  * Map interface name to
1061  * interface structure pointer.
1062  */
1063 struct ifnet *
1064 ifunit(const char *name)
1065 {
1066 	struct ifnet *ifp;
1067 
1068 	IFNET_RLOCK();
1069 	TAILQ_FOREACH(ifp, &ifnet, if_link) {
1070 		if (strncmp(name, ifp->if_xname, IFNAMSIZ) == 0)
1071 			break;
1072 	}
1073 	IFNET_RUNLOCK();
1074 	return (ifp);
1075 }
1076 
1077 /*
1078  * Hardware specific interface ioctls.
1079  */
1080 static int
1081 ifhwioctl(u_long cmd, struct ifnet *ifp, caddr_t data, struct thread *td)
1082 {
1083 	struct ifreq *ifr;
1084 	struct ifstat *ifs;
1085 	int error = 0;
1086 	int new_flags;
1087 	size_t namelen, onamelen;
1088 	char new_name[IFNAMSIZ];
1089 	struct ifaddr *ifa;
1090 	struct sockaddr_dl *sdl;
1091 
1092 	ifr = (struct ifreq *)data;
1093 	switch (cmd) {
1094 	case SIOCGIFINDEX:
1095 		ifr->ifr_index = ifp->if_index;
1096 		break;
1097 
1098 	case SIOCGIFFLAGS:
1099 		ifr->ifr_flags = ifp->if_flags & 0xffff;
1100 		ifr->ifr_flagshigh = ifp->if_flags >> 16;
1101 		break;
1102 
1103 	case SIOCGIFCAP:
1104 		ifr->ifr_reqcap = ifp->if_capabilities;
1105 		ifr->ifr_curcap = ifp->if_capenable;
1106 		break;
1107 
1108 #ifdef MAC
1109 	case SIOCGIFMAC:
1110 		error = mac_ioctl_ifnet_get(td->td_ucred, ifr, ifp);
1111 		break;
1112 #endif
1113 
1114 	case SIOCGIFMETRIC:
1115 		ifr->ifr_metric = ifp->if_metric;
1116 		break;
1117 
1118 	case SIOCGIFMTU:
1119 		ifr->ifr_mtu = ifp->if_mtu;
1120 		break;
1121 
1122 	case SIOCGIFPHYS:
1123 		ifr->ifr_phys = ifp->if_physical;
1124 		break;
1125 
1126 	case SIOCSIFFLAGS:
1127 		error = suser(td);
1128 		if (error)
1129 			return (error);
1130 		new_flags = (ifr->ifr_flags & 0xffff) |
1131 		    (ifr->ifr_flagshigh << 16);
1132 		if (ifp->if_flags & IFF_SMART) {
1133 			/* Smart drivers twiddle their own routes */
1134 		} else if (ifp->if_flags & IFF_UP &&
1135 		    (new_flags & IFF_UP) == 0) {
1136 			int s = splimp();
1137 			if_down(ifp);
1138 			splx(s);
1139 		} else if (new_flags & IFF_UP &&
1140 		    (ifp->if_flags & IFF_UP) == 0) {
1141 			int s = splimp();
1142 			if_up(ifp);
1143 			splx(s);
1144 		}
1145 		ifp->if_flags = (ifp->if_flags & IFF_CANTCHANGE) |
1146 			(new_flags &~ IFF_CANTCHANGE);
1147 		if (new_flags & IFF_PPROMISC) {
1148 			/* Permanently promiscuous mode requested */
1149 			ifp->if_flags |= IFF_PROMISC;
1150 		} else if (ifp->if_pcount == 0) {
1151 			ifp->if_flags &= ~IFF_PROMISC;
1152 		}
1153 		if (ifp->if_ioctl) {
1154 			IFF_LOCKGIANT(ifp);
1155 			(void) (*ifp->if_ioctl)(ifp, cmd, data);
1156 			IFF_UNLOCKGIANT(ifp);
1157 		}
1158 		getmicrotime(&ifp->if_lastchange);
1159 		break;
1160 
1161 	case SIOCSIFCAP:
1162 		error = suser(td);
1163 		if (error)
1164 			return (error);
1165 		if (ifp->if_ioctl == NULL)
1166 			return (EOPNOTSUPP);
1167 		if (ifr->ifr_reqcap & ~ifp->if_capabilities)
1168 			return (EINVAL);
1169 		IFF_LOCKGIANT(ifp);
1170 		error = (*ifp->if_ioctl)(ifp, cmd, data);
1171 		IFF_UNLOCKGIANT(ifp);
1172 		if (error == 0)
1173 			getmicrotime(&ifp->if_lastchange);
1174 		break;
1175 
1176 #ifdef MAC
1177 	case SIOCSIFMAC:
1178 		error = mac_ioctl_ifnet_set(td->td_ucred, ifr, ifp);
1179 		break;
1180 #endif
1181 
1182 	case SIOCSIFNAME:
1183 		error = suser(td);
1184 		if (error != 0)
1185 			return (error);
1186 		error = copyinstr(ifr->ifr_data, new_name, IFNAMSIZ, NULL);
1187 		if (error != 0)
1188 			return (error);
1189 		if (new_name[0] == '\0')
1190 			return (EINVAL);
1191 		if (ifunit(new_name) != NULL)
1192 			return (EEXIST);
1193 
1194 		EVENTHANDLER_INVOKE(ifnet_departure_event, ifp);
1195 		/* Announce the departure of the interface. */
1196 		rt_ifannouncemsg(ifp, IFAN_DEPARTURE);
1197 
1198 		log(LOG_INFO, "%s: changing name to '%s'\n",
1199 		    ifp->if_xname, new_name);
1200 
1201 		strlcpy(ifp->if_xname, new_name, sizeof(ifp->if_xname));
1202 		ifa = ifaddr_byindex(ifp->if_index);
1203 		IFA_LOCK(ifa);
1204 		sdl = (struct sockaddr_dl *)ifa->ifa_addr;
1205 		namelen = strlen(new_name);
1206 		onamelen = sdl->sdl_nlen;
1207 		/*
1208 		 * Move the address if needed.  This is safe because we
1209 		 * allocate space for a name of length IFNAMSIZ when we
1210 		 * create this in if_attach().
1211 		 */
1212 		if (namelen != onamelen) {
1213 			bcopy(sdl->sdl_data + onamelen,
1214 			    sdl->sdl_data + namelen, sdl->sdl_alen);
1215 		}
1216 		bcopy(new_name, sdl->sdl_data, namelen);
1217 		sdl->sdl_nlen = namelen;
1218 		sdl = (struct sockaddr_dl *)ifa->ifa_netmask;
1219 		bzero(sdl->sdl_data, onamelen);
1220 		while (namelen != 0)
1221 			sdl->sdl_data[--namelen] = 0xff;
1222 		IFA_UNLOCK(ifa);
1223 
1224 		EVENTHANDLER_INVOKE(ifnet_arrival_event, ifp);
1225 		/* Announce the return of the interface. */
1226 		rt_ifannouncemsg(ifp, IFAN_ARRIVAL);
1227 		break;
1228 
1229 	case SIOCSIFMETRIC:
1230 		error = suser(td);
1231 		if (error)
1232 			return (error);
1233 		ifp->if_metric = ifr->ifr_metric;
1234 		getmicrotime(&ifp->if_lastchange);
1235 		break;
1236 
1237 	case SIOCSIFPHYS:
1238 		error = suser(td);
1239 		if (error)
1240 			return (error);
1241 		if (ifp->if_ioctl == NULL)
1242 			return (EOPNOTSUPP);
1243 		IFF_LOCKGIANT(ifp);
1244 		error = (*ifp->if_ioctl)(ifp, cmd, data);
1245 		IFF_UNLOCKGIANT(ifp);
1246 		if (error == 0)
1247 			getmicrotime(&ifp->if_lastchange);
1248 		break;
1249 
1250 	case SIOCSIFMTU:
1251 	{
1252 		u_long oldmtu = ifp->if_mtu;
1253 
1254 		error = suser(td);
1255 		if (error)
1256 			return (error);
1257 		if (ifr->ifr_mtu < IF_MINMTU || ifr->ifr_mtu > IF_MAXMTU)
1258 			return (EINVAL);
1259 		if (ifp->if_ioctl == NULL)
1260 			return (EOPNOTSUPP);
1261 		IFF_LOCKGIANT(ifp);
1262 		error = (*ifp->if_ioctl)(ifp, cmd, data);
1263 		IFF_UNLOCKGIANT(ifp);
1264 		if (error == 0) {
1265 			getmicrotime(&ifp->if_lastchange);
1266 			rt_ifmsg(ifp);
1267 		}
1268 		/*
1269 		 * If the link MTU changed, do network layer specific procedure.
1270 		 */
1271 		if (ifp->if_mtu != oldmtu) {
1272 #ifdef INET6
1273 			nd6_setmtu(ifp);
1274 #endif
1275 		}
1276 		break;
1277 	}
1278 
1279 	case SIOCADDMULTI:
1280 	case SIOCDELMULTI:
1281 		error = suser(td);
1282 		if (error)
1283 			return (error);
1284 
1285 		/* Don't allow group membership on non-multicast interfaces. */
1286 		if ((ifp->if_flags & IFF_MULTICAST) == 0)
1287 			return (EOPNOTSUPP);
1288 
1289 		/* Don't let users screw up protocols' entries. */
1290 		if (ifr->ifr_addr.sa_family != AF_LINK)
1291 			return (EINVAL);
1292 
1293 		if (cmd == SIOCADDMULTI) {
1294 			struct ifmultiaddr *ifma;
1295 			error = if_addmulti(ifp, &ifr->ifr_addr, &ifma);
1296 		} else {
1297 			error = if_delmulti(ifp, &ifr->ifr_addr);
1298 		}
1299 		if (error == 0)
1300 			getmicrotime(&ifp->if_lastchange);
1301 		break;
1302 
1303 	case SIOCSIFPHYADDR:
1304 	case SIOCDIFPHYADDR:
1305 #ifdef INET6
1306 	case SIOCSIFPHYADDR_IN6:
1307 #endif
1308 	case SIOCSLIFPHYADDR:
1309 	case SIOCSIFMEDIA:
1310 	case SIOCSIFGENERIC:
1311 		error = suser(td);
1312 		if (error)
1313 			return (error);
1314 		if (ifp->if_ioctl == NULL)
1315 			return (EOPNOTSUPP);
1316 		IFF_LOCKGIANT(ifp);
1317 		error = (*ifp->if_ioctl)(ifp, cmd, data);
1318 		IFF_UNLOCKGIANT(ifp);
1319 		if (error == 0)
1320 			getmicrotime(&ifp->if_lastchange);
1321 		break;
1322 
1323 	case SIOCGIFSTATUS:
1324 		ifs = (struct ifstat *)data;
1325 		ifs->ascii[0] = '\0';
1326 
1327 	case SIOCGIFPSRCADDR:
1328 	case SIOCGIFPDSTADDR:
1329 	case SIOCGLIFPHYADDR:
1330 	case SIOCGIFMEDIA:
1331 	case SIOCGIFGENERIC:
1332 		if (ifp->if_ioctl == NULL)
1333 			return (EOPNOTSUPP);
1334 		IFF_LOCKGIANT(ifp);
1335 		error = (*ifp->if_ioctl)(ifp, cmd, data);
1336 		IFF_UNLOCKGIANT(ifp);
1337 		break;
1338 
1339 	case SIOCSIFLLADDR:
1340 		error = suser(td);
1341 		if (error)
1342 			return (error);
1343 		error = if_setlladdr(ifp,
1344 		    ifr->ifr_addr.sa_data, ifr->ifr_addr.sa_len);
1345 		break;
1346 
1347 	default:
1348 		error = ENOIOCTL;
1349 		break;
1350 	}
1351 	return (error);
1352 }
1353 
1354 /*
1355  * Interface ioctls.
1356  */
1357 int
1358 ifioctl(struct socket *so, u_long cmd, caddr_t data, struct thread *td)
1359 {
1360 	struct ifnet *ifp;
1361 	struct ifreq *ifr;
1362 	int error;
1363 	int oif_flags;
1364 
1365 	switch (cmd) {
1366 	case SIOCGIFCONF:
1367 	case OSIOCGIFCONF:
1368 		return (ifconf(cmd, data));
1369 	}
1370 	ifr = (struct ifreq *)data;
1371 
1372 	switch (cmd) {
1373 	case SIOCIFCREATE:
1374 	case SIOCIFDESTROY:
1375 		if ((error = suser(td)) != 0)
1376 			return (error);
1377 		return ((cmd == SIOCIFCREATE) ?
1378 			if_clone_create(ifr->ifr_name, sizeof(ifr->ifr_name)) :
1379 			if_clone_destroy(ifr->ifr_name));
1380 
1381 	case SIOCIFGCLONERS:
1382 		return (if_clone_list((struct if_clonereq *)data));
1383 	}
1384 
1385 	ifp = ifunit(ifr->ifr_name);
1386 	if (ifp == 0)
1387 		return (ENXIO);
1388 
1389 	error = ifhwioctl(cmd, ifp, data, td);
1390 	if (error != ENOIOCTL)
1391 		return (error);
1392 
1393 	oif_flags = ifp->if_flags;
1394 	if (so->so_proto == 0)
1395 		return (EOPNOTSUPP);
1396 #ifndef COMPAT_43
1397 	error = ((*so->so_proto->pr_usrreqs->pru_control)(so, cmd,
1398 								 data,
1399 								 ifp, td));
1400 #else
1401 	{
1402 		int ocmd = cmd;
1403 
1404 		switch (cmd) {
1405 
1406 		case SIOCSIFDSTADDR:
1407 		case SIOCSIFADDR:
1408 		case SIOCSIFBRDADDR:
1409 		case SIOCSIFNETMASK:
1410 #if BYTE_ORDER != BIG_ENDIAN
1411 			if (ifr->ifr_addr.sa_family == 0 &&
1412 			    ifr->ifr_addr.sa_len < 16) {
1413 				ifr->ifr_addr.sa_family = ifr->ifr_addr.sa_len;
1414 				ifr->ifr_addr.sa_len = 16;
1415 			}
1416 #else
1417 			if (ifr->ifr_addr.sa_len == 0)
1418 				ifr->ifr_addr.sa_len = 16;
1419 #endif
1420 			break;
1421 
1422 		case OSIOCGIFADDR:
1423 			cmd = SIOCGIFADDR;
1424 			break;
1425 
1426 		case OSIOCGIFDSTADDR:
1427 			cmd = SIOCGIFDSTADDR;
1428 			break;
1429 
1430 		case OSIOCGIFBRDADDR:
1431 			cmd = SIOCGIFBRDADDR;
1432 			break;
1433 
1434 		case OSIOCGIFNETMASK:
1435 			cmd = SIOCGIFNETMASK;
1436 		}
1437 		error =  ((*so->so_proto->pr_usrreqs->pru_control)(so,
1438 								   cmd,
1439 								   data,
1440 								   ifp, td));
1441 		switch (ocmd) {
1442 
1443 		case OSIOCGIFADDR:
1444 		case OSIOCGIFDSTADDR:
1445 		case OSIOCGIFBRDADDR:
1446 		case OSIOCGIFNETMASK:
1447 			*(u_short *)&ifr->ifr_addr = ifr->ifr_addr.sa_family;
1448 
1449 		}
1450 	}
1451 #endif /* COMPAT_43 */
1452 
1453 	if ((oif_flags ^ ifp->if_flags) & IFF_UP) {
1454 #ifdef INET6
1455 		DELAY(100);/* XXX: temporary workaround for fxp issue*/
1456 		if (ifp->if_flags & IFF_UP) {
1457 			int s = splimp();
1458 			in6_if_up(ifp);
1459 			splx(s);
1460 		}
1461 #endif
1462 	}
1463 	return (error);
1464 }
1465 
1466 /*
1467  * Set/clear promiscuous mode on interface ifp based on the truth value
1468  * of pswitch.  The calls are reference counted so that only the first
1469  * "on" request actually has an effect, as does the final "off" request.
1470  * Results are undefined if the "off" and "on" requests are not matched.
1471  */
1472 int
1473 ifpromisc(struct ifnet *ifp, int pswitch)
1474 {
1475 	struct ifreq ifr;
1476 	int error;
1477 	int oldflags, oldpcount;
1478 
1479 	oldpcount = ifp->if_pcount;
1480 	oldflags = ifp->if_flags;
1481 	if (ifp->if_flags & IFF_PPROMISC) {
1482 		/* Do nothing if device is in permanently promiscuous mode */
1483 		ifp->if_pcount += pswitch ? 1 : -1;
1484 		return (0);
1485 	}
1486 	if (pswitch) {
1487 		/*
1488 		 * If the device is not configured up, we cannot put it in
1489 		 * promiscuous mode.
1490 		 */
1491 		if ((ifp->if_flags & IFF_UP) == 0)
1492 			return (ENETDOWN);
1493 		if (ifp->if_pcount++ != 0)
1494 			return (0);
1495 		ifp->if_flags |= IFF_PROMISC;
1496 	} else {
1497 		if (--ifp->if_pcount > 0)
1498 			return (0);
1499 		ifp->if_flags &= ~IFF_PROMISC;
1500 	}
1501 	ifr.ifr_flags = ifp->if_flags & 0xffff;
1502 	ifr.ifr_flagshigh = ifp->if_flags >> 16;
1503 	IFF_LOCKGIANT(ifp);
1504 	error = (*ifp->if_ioctl)(ifp, SIOCSIFFLAGS, (caddr_t)&ifr);
1505 	IFF_UNLOCKGIANT(ifp);
1506 	if (error == 0) {
1507 		log(LOG_INFO, "%s: promiscuous mode %s\n",
1508 		    ifp->if_xname,
1509 		    (ifp->if_flags & IFF_PROMISC) ? "enabled" : "disabled");
1510 		rt_ifmsg(ifp);
1511 	} else {
1512 		ifp->if_pcount = oldpcount;
1513 		ifp->if_flags = oldflags;
1514 	}
1515 	return error;
1516 }
1517 
1518 /*
1519  * Return interface configuration
1520  * of system.  List may be used
1521  * in later ioctl's (above) to get
1522  * other information.
1523  */
1524 /*ARGSUSED*/
1525 static int
1526 ifconf(u_long cmd, caddr_t data)
1527 {
1528 	struct ifconf *ifc = (struct ifconf *)data;
1529 	struct ifnet *ifp;
1530 	struct ifaddr *ifa;
1531 	struct ifreq ifr;
1532 	struct sbuf *sb;
1533 	int error, full = 0, valid_len, max_len;
1534 
1535 	/* Limit initial buffer size to MAXPHYS to avoid DoS from userspace. */
1536 	max_len = MAXPHYS - 1;
1537 
1538 again:
1539 	if (ifc->ifc_len <= max_len) {
1540 		max_len = ifc->ifc_len;
1541 		full = 1;
1542 	}
1543 	sb = sbuf_new(NULL, NULL, max_len + 1, SBUF_FIXEDLEN);
1544 	max_len = 0;
1545 	valid_len = 0;
1546 
1547 	IFNET_RLOCK();		/* could sleep XXX */
1548 	TAILQ_FOREACH(ifp, &ifnet, if_link) {
1549 		int addrs;
1550 
1551 		if (strlcpy(ifr.ifr_name, ifp->if_xname, sizeof(ifr.ifr_name))
1552 		    >= sizeof(ifr.ifr_name))
1553 			return (ENAMETOOLONG);
1554 
1555 		addrs = 0;
1556 		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1557 			struct sockaddr *sa = ifa->ifa_addr;
1558 
1559 			if (jailed(curthread->td_ucred) &&
1560 			    prison_if(curthread->td_ucred, sa))
1561 				continue;
1562 			addrs++;
1563 #ifdef COMPAT_43
1564 			if (cmd == OSIOCGIFCONF) {
1565 				struct osockaddr *osa =
1566 					 (struct osockaddr *)&ifr.ifr_addr;
1567 				ifr.ifr_addr = *sa;
1568 				osa->sa_family = sa->sa_family;
1569 				sbuf_bcat(sb, &ifr, sizeof(ifr));
1570 				max_len += sizeof(ifr);
1571 			} else
1572 #endif
1573 			if (sa->sa_len <= sizeof(*sa)) {
1574 				ifr.ifr_addr = *sa;
1575 				sbuf_bcat(sb, &ifr, sizeof(ifr));
1576 				max_len += sizeof(ifr);
1577 			} else {
1578 				sbuf_bcat(sb, &ifr,
1579 				    offsetof(struct ifreq, ifr_addr));
1580 				max_len += offsetof(struct ifreq, ifr_addr);
1581 				sbuf_bcat(sb, sa, sa->sa_len);
1582 				max_len += sa->sa_len;
1583 			}
1584 
1585 			if (!sbuf_overflowed(sb))
1586 				valid_len = sbuf_len(sb);
1587 		}
1588 		if (addrs == 0) {
1589 			bzero((caddr_t)&ifr.ifr_addr, sizeof(ifr.ifr_addr));
1590 			sbuf_bcat(sb, &ifr, sizeof(ifr));
1591 			max_len += sizeof(ifr);
1592 
1593 			if (!sbuf_overflowed(sb))
1594 				valid_len = sbuf_len(sb);
1595 		}
1596 	}
1597 	IFNET_RUNLOCK();
1598 
1599 	/*
1600 	 * If we didn't allocate enough space (uncommon), try again.  If
1601 	 * we have already allocated as much space as we are allowed,
1602 	 * return what we've got.
1603 	 */
1604 	if (valid_len != max_len && !full) {
1605 		sbuf_delete(sb);
1606 		goto again;
1607 	}
1608 
1609 	ifc->ifc_len = valid_len;
1610 	sbuf_finish(sb);
1611 	error = copyout(sbuf_data(sb), ifc->ifc_req, ifc->ifc_len);
1612 	sbuf_delete(sb);
1613 	return (error);
1614 }
1615 
1616 /*
1617  * Just like if_promisc(), but for all-multicast-reception mode.
1618  */
1619 int
1620 if_allmulti(struct ifnet *ifp, int onswitch)
1621 {
1622 	int error = 0;
1623 	int s = splimp();
1624 	struct ifreq ifr;
1625 
1626 	if (onswitch) {
1627 		if (ifp->if_amcount++ == 0) {
1628 			ifp->if_flags |= IFF_ALLMULTI;
1629 			ifr.ifr_flags = ifp->if_flags & 0xffff;
1630 			ifr.ifr_flagshigh = ifp->if_flags >> 16;
1631 			IFF_LOCKGIANT(ifp);
1632 			error = ifp->if_ioctl(ifp, SIOCSIFFLAGS, (caddr_t)&ifr);
1633 			IFF_UNLOCKGIANT(ifp);
1634 		}
1635 	} else {
1636 		if (ifp->if_amcount > 1) {
1637 			ifp->if_amcount--;
1638 		} else {
1639 			ifp->if_amcount = 0;
1640 			ifp->if_flags &= ~IFF_ALLMULTI;
1641 			ifr.ifr_flags = ifp->if_flags & 0xffff;;
1642 			ifr.ifr_flagshigh = ifp->if_flags >> 16;
1643 			IFF_LOCKGIANT(ifp);
1644 			error = ifp->if_ioctl(ifp, SIOCSIFFLAGS, (caddr_t)&ifr);
1645 			IFF_UNLOCKGIANT(ifp);
1646 		}
1647 	}
1648 	splx(s);
1649 
1650 	if (error == 0)
1651 		rt_ifmsg(ifp);
1652 	return error;
1653 }
1654 
1655 /*
1656  * Add a multicast listenership to the interface in question.
1657  * The link layer provides a routine which converts
1658  */
1659 int
1660 if_addmulti(struct ifnet *ifp, struct sockaddr *sa, struct ifmultiaddr **retifma)
1661 {
1662 	struct sockaddr *llsa, *dupsa;
1663 	int error, s;
1664 	struct ifmultiaddr *ifma;
1665 
1666 	/*
1667 	 * If the matching multicast address already exists
1668 	 * then don't add a new one, just add a reference
1669 	 */
1670 	TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
1671 		if (equal(sa, ifma->ifma_addr)) {
1672 			ifma->ifma_refcount++;
1673 			if (retifma)
1674 				*retifma = ifma;
1675 			return 0;
1676 		}
1677 	}
1678 
1679 	/*
1680 	 * Give the link layer a chance to accept/reject it, and also
1681 	 * find out which AF_LINK address this maps to, if it isn't one
1682 	 * already.
1683 	 */
1684 	if (ifp->if_resolvemulti) {
1685 		error = ifp->if_resolvemulti(ifp, &llsa, sa);
1686 		if (error) return error;
1687 	} else {
1688 		llsa = 0;
1689 	}
1690 
1691 	MALLOC(ifma, struct ifmultiaddr *, sizeof *ifma, M_IFMADDR, M_WAITOK);
1692 	MALLOC(dupsa, struct sockaddr *, sa->sa_len, M_IFMADDR, M_WAITOK);
1693 	bcopy(sa, dupsa, sa->sa_len);
1694 
1695 	ifma->ifma_addr = dupsa;
1696 	ifma->ifma_lladdr = llsa;
1697 	ifma->ifma_ifp = ifp;
1698 	ifma->ifma_refcount = 1;
1699 	ifma->ifma_protospec = 0;
1700 	rt_newmaddrmsg(RTM_NEWMADDR, ifma);
1701 
1702 	/*
1703 	 * Some network interfaces can scan the address list at
1704 	 * interrupt time; lock them out.
1705 	 */
1706 	s = splimp();
1707 	TAILQ_INSERT_HEAD(&ifp->if_multiaddrs, ifma, ifma_link);
1708 	splx(s);
1709 	if (retifma != NULL)
1710 		*retifma = ifma;
1711 
1712 	if (llsa != 0) {
1713 		TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
1714 			if (equal(ifma->ifma_addr, llsa))
1715 				break;
1716 		}
1717 		if (ifma) {
1718 			ifma->ifma_refcount++;
1719 		} else {
1720 			MALLOC(ifma, struct ifmultiaddr *, sizeof *ifma,
1721 			       M_IFMADDR, M_WAITOK);
1722 			MALLOC(dupsa, struct sockaddr *, llsa->sa_len,
1723 			       M_IFMADDR, M_WAITOK);
1724 			bcopy(llsa, dupsa, llsa->sa_len);
1725 			ifma->ifma_addr = dupsa;
1726 			ifma->ifma_lladdr = NULL;
1727 			ifma->ifma_ifp = ifp;
1728 			ifma->ifma_refcount = 1;
1729 			ifma->ifma_protospec = 0;
1730 			s = splimp();
1731 			TAILQ_INSERT_HEAD(&ifp->if_multiaddrs, ifma, ifma_link);
1732 			splx(s);
1733 		}
1734 	}
1735 	/*
1736 	 * We are certain we have added something, so call down to the
1737 	 * interface to let them know about it.
1738 	 */
1739 	s = splimp();
1740 	IFF_LOCKGIANT(ifp);
1741 	ifp->if_ioctl(ifp, SIOCADDMULTI, 0);
1742 	IFF_UNLOCKGIANT(ifp);
1743 	splx(s);
1744 
1745 	return 0;
1746 }
1747 
1748 /*
1749  * Remove a reference to a multicast address on this interface.  Yell
1750  * if the request does not match an existing membership.
1751  */
1752 int
1753 if_delmulti(struct ifnet *ifp, struct sockaddr *sa)
1754 {
1755 	struct ifmultiaddr *ifma;
1756 	int s;
1757 
1758 	TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link)
1759 		if (equal(sa, ifma->ifma_addr))
1760 			break;
1761 	if (ifma == 0)
1762 		return ENOENT;
1763 
1764 	if (ifma->ifma_refcount > 1) {
1765 		ifma->ifma_refcount--;
1766 		return 0;
1767 	}
1768 
1769 	rt_newmaddrmsg(RTM_DELMADDR, ifma);
1770 	sa = ifma->ifma_lladdr;
1771 	s = splimp();
1772 	TAILQ_REMOVE(&ifp->if_multiaddrs, ifma, ifma_link);
1773 	/*
1774 	 * Make sure the interface driver is notified
1775 	 * in the case of a link layer mcast group being left.
1776 	 */
1777 	if (ifma->ifma_addr->sa_family == AF_LINK && sa == 0) {
1778 		IFF_LOCKGIANT(ifp);
1779 		ifp->if_ioctl(ifp, SIOCDELMULTI, 0);
1780 		IFF_UNLOCKGIANT(ifp);
1781 	}
1782 	splx(s);
1783 	free(ifma->ifma_addr, M_IFMADDR);
1784 	free(ifma, M_IFMADDR);
1785 	if (sa == 0)
1786 		return 0;
1787 
1788 	/*
1789 	 * Now look for the link-layer address which corresponds to
1790 	 * this network address.  It had been squirreled away in
1791 	 * ifma->ifma_lladdr for this purpose (so we don't have
1792 	 * to call ifp->if_resolvemulti() again), and we saved that
1793 	 * value in sa above.  If some nasty deleted the
1794 	 * link-layer address out from underneath us, we can deal because
1795 	 * the address we stored was is not the same as the one which was
1796 	 * in the record for the link-layer address.  (So we don't complain
1797 	 * in that case.)
1798 	 */
1799 	TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link)
1800 		if (equal(sa, ifma->ifma_addr))
1801 			break;
1802 	if (ifma == 0)
1803 		return 0;
1804 
1805 	if (ifma->ifma_refcount > 1) {
1806 		ifma->ifma_refcount--;
1807 		return 0;
1808 	}
1809 
1810 	s = splimp();
1811 	TAILQ_REMOVE(&ifp->if_multiaddrs, ifma, ifma_link);
1812 	IFF_LOCKGIANT(ifp);
1813 	ifp->if_ioctl(ifp, SIOCDELMULTI, 0);
1814 	IFF_UNLOCKGIANT(ifp);
1815 	splx(s);
1816 	free(ifma->ifma_addr, M_IFMADDR);
1817 	free(sa, M_IFMADDR);
1818 	free(ifma, M_IFMADDR);
1819 
1820 	return 0;
1821 }
1822 
1823 /*
1824  * Set the link layer address on an interface.
1825  *
1826  * At this time we only support certain types of interfaces,
1827  * and we don't allow the length of the address to change.
1828  */
1829 int
1830 if_setlladdr(struct ifnet *ifp, const u_char *lladdr, int len)
1831 {
1832 	struct sockaddr_dl *sdl;
1833 	struct ifaddr *ifa;
1834 	struct ifreq ifr;
1835 
1836 	ifa = ifaddr_byindex(ifp->if_index);
1837 	if (ifa == NULL)
1838 		return (EINVAL);
1839 	sdl = (struct sockaddr_dl *)ifa->ifa_addr;
1840 	if (sdl == NULL)
1841 		return (EINVAL);
1842 	if (len != sdl->sdl_alen)	/* don't allow length to change */
1843 		return (EINVAL);
1844 	switch (ifp->if_type) {
1845 	case IFT_ETHER:			/* these types use struct arpcom */
1846 	case IFT_FDDI:
1847 	case IFT_XETHER:
1848 	case IFT_ISO88025:
1849 	case IFT_L2VLAN:
1850 		bcopy(lladdr, IFP2AC(ifp)->ac_enaddr, len);
1851 		/*
1852 		 * XXX We also need to store the lladdr in LLADDR(sdl),
1853 		 * which is done below. This is a pain because we must
1854 		 * remember to keep the info in sync.
1855 		 */
1856 		/* FALLTHROUGH */
1857 	case IFT_ARCNET:
1858 		bcopy(lladdr, LLADDR(sdl), len);
1859 		break;
1860 	default:
1861 		return (ENODEV);
1862 	}
1863 	/*
1864 	 * If the interface is already up, we need
1865 	 * to re-init it in order to reprogram its
1866 	 * address filter.
1867 	 */
1868 	if ((ifp->if_flags & IFF_UP) != 0) {
1869 		IFF_LOCKGIANT(ifp);
1870 		ifp->if_flags &= ~IFF_UP;
1871 		ifr.ifr_flags = ifp->if_flags & 0xffff;
1872 		ifr.ifr_flagshigh = ifp->if_flags >> 16;
1873 		(*ifp->if_ioctl)(ifp, SIOCSIFFLAGS, (caddr_t)&ifr);
1874 		ifp->if_flags |= IFF_UP;
1875 		ifr.ifr_flags = ifp->if_flags & 0xffff;
1876 		ifr.ifr_flagshigh = ifp->if_flags >> 16;
1877 		(*ifp->if_ioctl)(ifp, SIOCSIFFLAGS, (caddr_t)&ifr);
1878 		IFF_UNLOCKGIANT(ifp);
1879 #ifdef INET
1880 		/*
1881 		 * Also send gratuitous ARPs to notify other nodes about
1882 		 * the address change.
1883 		 */
1884 		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1885 			if (ifa->ifa_addr != NULL &&
1886 			    ifa->ifa_addr->sa_family == AF_INET)
1887 				arp_ifinit(ifp, ifa);
1888 		}
1889 #endif
1890 	}
1891 	return (0);
1892 }
1893 
1894 struct ifmultiaddr *
1895 ifmaof_ifpforaddr(struct sockaddr *sa, struct ifnet *ifp)
1896 {
1897 	struct ifmultiaddr *ifma;
1898 
1899 	TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link)
1900 		if (equal(ifma->ifma_addr, sa))
1901 			break;
1902 
1903 	return ifma;
1904 }
1905 
1906 /*
1907  * The name argument must be a pointer to storage which will last as
1908  * long as the interface does.  For physical devices, the result of
1909  * device_get_name(dev) is a good choice and for pseudo-devices a
1910  * static string works well.
1911  */
1912 void
1913 if_initname(struct ifnet *ifp, const char *name, int unit)
1914 {
1915 	ifp->if_dname = name;
1916 	ifp->if_dunit = unit;
1917 	if (unit != IF_DUNIT_NONE)
1918 		snprintf(ifp->if_xname, IFNAMSIZ, "%s%d", name, unit);
1919 	else
1920 		strlcpy(ifp->if_xname, name, IFNAMSIZ);
1921 }
1922 
1923 int
1924 if_printf(struct ifnet *ifp, const char * fmt, ...)
1925 {
1926 	va_list ap;
1927 	int retval;
1928 
1929 	retval = printf("%s: ", ifp->if_xname);
1930 	va_start(ap, fmt);
1931 	retval += vprintf(fmt, ap);
1932 	va_end(ap);
1933 	return (retval);
1934 }
1935 
1936 /*
1937  * When an interface is marked IFF_NEEDSGIANT, its if_start() routine cannot
1938  * be called without Giant.  However, we often can't acquire the Giant lock
1939  * at those points; instead, we run it via a task queue that holds Giant via
1940  * if_start_deferred.
1941  *
1942  * XXXRW: We need to make sure that the ifnet isn't fully detached until any
1943  * outstanding if_start_deferred() tasks that will run after the free.  This
1944  * probably means waiting in if_detach().
1945  */
1946 void
1947 if_start(struct ifnet *ifp)
1948 {
1949 
1950 	NET_ASSERT_GIANT();
1951 
1952 	if ((ifp->if_flags & IFF_NEEDSGIANT) != 0 && debug_mpsafenet != 0) {
1953 		if (mtx_owned(&Giant))
1954 			(*(ifp)->if_start)(ifp);
1955 		else
1956 			taskqueue_enqueue(taskqueue_swi_giant,
1957 			    &ifp->if_starttask);
1958 	} else
1959 		(*(ifp)->if_start)(ifp);
1960 }
1961 
1962 static void
1963 if_start_deferred(void *context, int pending)
1964 {
1965 	struct ifnet *ifp;
1966 
1967 	/*
1968 	 * This code must be entered with Giant, and should never run if
1969 	 * we're not running with debug.mpsafenet.
1970 	 */
1971 	KASSERT(debug_mpsafenet != 0, ("if_start_deferred: debug.mpsafenet"));
1972 	GIANT_REQUIRED;
1973 
1974 	ifp = (struct ifnet *)context;
1975 	(ifp->if_start)(ifp);
1976 }
1977 
1978 int
1979 if_handoff(struct ifqueue *ifq, struct mbuf *m, struct ifnet *ifp, int adjust)
1980 {
1981 	int active = 0;
1982 
1983 	IF_LOCK(ifq);
1984 	if (_IF_QFULL(ifq)) {
1985 		_IF_DROP(ifq);
1986 		IF_UNLOCK(ifq);
1987 		m_freem(m);
1988 		return (0);
1989 	}
1990 	if (ifp != NULL) {
1991 		ifp->if_obytes += m->m_pkthdr.len + adjust;
1992 		if (m->m_flags & (M_BCAST|M_MCAST))
1993 			ifp->if_omcasts++;
1994 		active = ifp->if_flags & IFF_OACTIVE;
1995 	}
1996 	_IF_ENQUEUE(ifq, m);
1997 	IF_UNLOCK(ifq);
1998 	if (ifp != NULL && !active)
1999 		if_start(ifp);
2000 	return (1);
2001 }
2002 
2003 SYSCTL_NODE(_net, PF_LINK, link, CTLFLAG_RW, 0, "Link layers");
2004 SYSCTL_NODE(_net_link, 0, generic, CTLFLAG_RW, 0, "Generic link-management");
2005