xref: /netbsd-src/sys/net/if.c (revision 76dfffe33547c37f8bdd446e3e4ab0f3c16cea4b)
1 /*	$NetBSD: if.c,v 1.37 1996/06/13 21:49:43 cgd Exp $	*/
2 
3 /*
4  * Copyright (c) 1980, 1986, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  *
35  *	@(#)if.c	8.3 (Berkeley) 1/4/94
36  */
37 
38 #include <sys/param.h>
39 #include <sys/mbuf.h>
40 #include <sys/systm.h>
41 #include <sys/proc.h>
42 #include <sys/socket.h>
43 #include <sys/socketvar.h>
44 #include <sys/protosw.h>
45 #include <sys/kernel.h>
46 #include <sys/ioctl.h>
47 
48 #include <net/if.h>
49 #include <net/if_dl.h>
50 #include <net/if_types.h>
51 #include <net/radix.h>
52 
53 int	ifqmaxlen = IFQ_MAXLEN;
54 void	if_slowtimo __P((void *arg));
55 
56 /*
57  * Network interface utility routines.
58  *
59  * Routines with ifa_ifwith* names take sockaddr *'s as
60  * parameters.
61  */
62 void
63 ifinit()
64 {
65 	register struct ifnet *ifp;
66 
67 	for (ifp = ifnet.tqh_first; ifp != 0; ifp = ifp->if_list.tqe_next)
68 		if (ifp->if_snd.ifq_maxlen == 0)
69 			ifp->if_snd.ifq_maxlen = ifqmaxlen;
70 	if_slowtimo(NULL);
71 }
72 
73 int if_index = 0;
74 struct ifaddr **ifnet_addrs;
75 
76 /*
77  * Attach an interface to the
78  * list of "active" interfaces.
79  */
80 void
81 if_attach(ifp)
82 	struct ifnet *ifp;
83 {
84 	unsigned socksize, ifasize;
85 	int namelen, masklen;
86 	register struct sockaddr_dl *sdl;
87 	register struct ifaddr *ifa;
88 	static int if_indexlim = 8;
89 
90 	if (if_index == 0)
91 		TAILQ_INIT(&ifnet);
92 	TAILQ_INIT(&ifp->if_addrlist);
93 	TAILQ_INSERT_TAIL(&ifnet, ifp, if_list);
94 	ifp->if_index = ++if_index;
95 	if (ifnet_addrs == 0 || if_index >= if_indexlim) {
96 		unsigned n = (if_indexlim <<= 1) * sizeof(ifa);
97 		struct ifaddr **q = (struct ifaddr **)
98 					malloc(n, M_IFADDR, M_WAITOK);
99 		if (ifnet_addrs) {
100 			bcopy((caddr_t)ifnet_addrs, (caddr_t)q, n/2);
101 			free((caddr_t)ifnet_addrs, M_IFADDR);
102 		}
103 		ifnet_addrs = q;
104 	}
105 	/*
106 	 * create a Link Level name for this device
107 	 */
108 	namelen = strlen(ifp->if_xname);
109 #define _offsetof(t, m) ((int)((caddr_t)&((t *)0)->m))
110 	masklen = _offsetof(struct sockaddr_dl, sdl_data[0]) + namelen;
111 	socksize = masklen + ifp->if_addrlen;
112 #define ROUNDUP(a) (1 + (((a) - 1) | (sizeof(long) - 1)))
113 	if (socksize < sizeof(*sdl))
114 		socksize = sizeof(*sdl);
115 	socksize = ROUNDUP(socksize);
116 	ifasize = sizeof(*ifa) + 2 * socksize;
117 	ifa = (struct ifaddr *)malloc(ifasize, M_IFADDR, M_WAITOK);
118 	bzero((caddr_t)ifa, ifasize);
119 	sdl = (struct sockaddr_dl *)(ifa + 1);
120 	sdl->sdl_len = socksize;
121 	sdl->sdl_family = AF_LINK;
122 	bcopy(ifp->if_xname, sdl->sdl_data, namelen);
123 	sdl->sdl_nlen = namelen;
124 	sdl->sdl_index = ifp->if_index;
125 	sdl->sdl_type = ifp->if_type;
126 	ifnet_addrs[if_index - 1] = ifa;
127 	ifa->ifa_ifp = ifp;
128 	ifa->ifa_rtrequest = link_rtrequest;
129 	TAILQ_INSERT_HEAD(&ifp->if_addrlist, ifa, ifa_list);
130 	ifa->ifa_addr = (struct sockaddr *)sdl;
131 	sdl = (struct sockaddr_dl *)(socksize + (caddr_t)sdl);
132 	ifa->ifa_netmask = (struct sockaddr *)sdl;
133 	sdl->sdl_len = masklen;
134 	while (namelen != 0)
135 		sdl->sdl_data[--namelen] = 0xff;
136 }
137 /*
138  * Locate an interface based on a complete address.
139  */
140 /*ARGSUSED*/
141 struct ifaddr *
142 ifa_ifwithaddr(addr)
143 	register struct sockaddr *addr;
144 {
145 	register struct ifnet *ifp;
146 	register struct ifaddr *ifa;
147 
148 #define	equal(a1, a2) \
149   (bcmp((caddr_t)(a1), (caddr_t)(a2), ((struct sockaddr *)(a1))->sa_len) == 0)
150 	for (ifp = ifnet.tqh_first; ifp != 0; ifp = ifp->if_list.tqe_next)
151 	    for (ifa = ifp->if_addrlist.tqh_first; ifa != 0; ifa = ifa->ifa_list.tqe_next) {
152 		if (ifa->ifa_addr->sa_family != addr->sa_family)
153 			continue;
154 		if (equal(addr, ifa->ifa_addr))
155 			return (ifa);
156 		if ((ifp->if_flags & IFF_BROADCAST) && ifa->ifa_broadaddr &&
157 		    equal(ifa->ifa_broadaddr, addr))
158 			return (ifa);
159 	}
160 	return ((struct ifaddr *)0);
161 }
162 /*
163  * Locate the point to point interface with a given destination address.
164  */
165 /*ARGSUSED*/
166 struct ifaddr *
167 ifa_ifwithdstaddr(addr)
168 	register struct sockaddr *addr;
169 {
170 	register struct ifnet *ifp;
171 	register struct ifaddr *ifa;
172 
173 	for (ifp = ifnet.tqh_first; ifp != 0; ifp = ifp->if_list.tqe_next)
174 	    if (ifp->if_flags & IFF_POINTOPOINT)
175 		for (ifa = ifp->if_addrlist.tqh_first; ifa != 0; ifa = ifa->ifa_list.tqe_next) {
176 			if (ifa->ifa_addr->sa_family != addr->sa_family ||
177 			    ifa->ifa_dstaddr == NULL)
178 				continue;
179 			if (equal(addr, ifa->ifa_dstaddr))
180 				return (ifa);
181 	}
182 	return ((struct ifaddr *)0);
183 }
184 
185 /*
186  * Find an interface on a specific network.  If many, choice
187  * is most specific found.
188  */
189 struct ifaddr *
190 ifa_ifwithnet(addr)
191 	struct sockaddr *addr;
192 {
193 	register struct ifnet *ifp;
194 	register struct ifaddr *ifa;
195 	struct ifaddr *ifa_maybe = 0;
196 	u_int af = addr->sa_family;
197 	char *addr_data = addr->sa_data, *cplim;
198 
199 	if (af == AF_LINK) {
200 	    register struct sockaddr_dl *sdl = (struct sockaddr_dl *)addr;
201 	    if (sdl->sdl_index && sdl->sdl_index <= if_index)
202 		return (ifnet_addrs[sdl->sdl_index - 1]);
203 	}
204 	for (ifp = ifnet.tqh_first; ifp != 0; ifp = ifp->if_list.tqe_next)
205 		for (ifa = ifp->if_addrlist.tqh_first; ifa != 0; ifa = ifa->ifa_list.tqe_next) {
206 			register char *cp, *cp2, *cp3;
207 
208 			if (ifa->ifa_addr->sa_family != af ||
209 			    ifa->ifa_netmask == 0)
210 				next: continue;
211 			cp = addr_data;
212 			cp2 = ifa->ifa_addr->sa_data;
213 			cp3 = ifa->ifa_netmask->sa_data;
214 			cplim = (char *)ifa->ifa_netmask +
215 				ifa->ifa_netmask->sa_len;
216 			while (cp3 < cplim)
217 				if ((*cp++ ^ *cp2++) & *cp3++)
218 				    /* want to continue for() loop */
219 					goto next;
220 			if (ifa_maybe == 0 ||
221 			    rn_refines((caddr_t)ifa->ifa_netmask,
222 			    (caddr_t)ifa_maybe->ifa_netmask))
223 				ifa_maybe = ifa;
224 		}
225 	return (ifa_maybe);
226 }
227 /*
228  * Find the interface of the addresss.
229  */
230 struct ifaddr *
231 ifa_ifwithladdr(addr)
232 	struct sockaddr *addr;
233 {
234 	struct ifaddr *ia;
235 
236 	if ((ia = ifa_ifwithaddr(addr)) || (ia = ifa_ifwithdstaddr(addr))
237 	    || (ia = ifa_ifwithnet(addr)))
238 		return (ia);
239 	return (NULL);
240 }
241 
242 /*
243  * Find an interface using a specific address family
244  */
245 struct ifaddr *
246 ifa_ifwithaf(af)
247 	register int af;
248 {
249 	register struct ifnet *ifp;
250 	register struct ifaddr *ifa;
251 
252 	for (ifp = ifnet.tqh_first; ifp != 0; ifp = ifp->if_list.tqe_next)
253 		for (ifa = ifp->if_addrlist.tqh_first; ifa != 0; ifa = ifa->ifa_list.tqe_next)
254 			if (ifa->ifa_addr->sa_family == af)
255 				return (ifa);
256 	return ((struct ifaddr *)0);
257 }
258 
259 /*
260  * Find an interface address specific to an interface best matching
261  * a given address.
262  */
263 struct ifaddr *
264 ifaof_ifpforaddr(addr, ifp)
265 	struct sockaddr *addr;
266 	register struct ifnet *ifp;
267 {
268 	register struct ifaddr *ifa;
269 	register char *cp, *cp2, *cp3;
270 	register char *cplim;
271 	struct ifaddr *ifa_maybe = 0;
272 	u_int af = addr->sa_family;
273 
274 	if (af >= AF_MAX)
275 		return (0);
276 	for (ifa = ifp->if_addrlist.tqh_first; ifa != 0; ifa = ifa->ifa_list.tqe_next) {
277 		if (ifa->ifa_addr->sa_family != af)
278 			continue;
279 		ifa_maybe = ifa;
280 		if (ifa->ifa_netmask == 0) {
281 			if (equal(addr, ifa->ifa_addr) ||
282 			    (ifa->ifa_dstaddr && equal(addr, ifa->ifa_dstaddr)))
283 				return (ifa);
284 			continue;
285 		}
286 		cp = addr->sa_data;
287 		cp2 = ifa->ifa_addr->sa_data;
288 		cp3 = ifa->ifa_netmask->sa_data;
289 		cplim = ifa->ifa_netmask->sa_len + (char *)ifa->ifa_netmask;
290 		for (; cp3 < cplim; cp3++)
291 			if ((*cp++ ^ *cp2++) & *cp3)
292 				break;
293 		if (cp3 == cplim)
294 			return (ifa);
295 	}
296 	return (ifa_maybe);
297 }
298 
299 #include <net/route.h>
300 
301 /*
302  * Default action when installing a route with a Link Level gateway.
303  * Lookup an appropriate real ifa to point to.
304  * This should be moved to /sys/net/link.c eventually.
305  */
306 void
307 link_rtrequest(cmd, rt, sa)
308 	int cmd;
309 	register struct rtentry *rt;
310 	struct sockaddr *sa;
311 {
312 	register struct ifaddr *ifa;
313 	struct sockaddr *dst;
314 	struct ifnet *ifp;
315 
316 	if (cmd != RTM_ADD || ((ifa = rt->rt_ifa) == 0) ||
317 	    ((ifp = ifa->ifa_ifp) == 0) || ((dst = rt_key(rt)) == 0))
318 		return;
319 	if ((ifa = ifaof_ifpforaddr(dst, ifp)) != NULL) {
320 		IFAFREE(rt->rt_ifa);
321 		rt->rt_ifa = ifa;
322 		ifa->ifa_refcnt++;
323 		if (ifa->ifa_rtrequest && ifa->ifa_rtrequest != link_rtrequest)
324 			ifa->ifa_rtrequest(cmd, rt, sa);
325 	}
326 }
327 
328 /*
329  * Mark an interface down and notify protocols of
330  * the transition.
331  * NOTE: must be called at splsoftnet or equivalent.
332  */
333 void
334 if_down(ifp)
335 	register struct ifnet *ifp;
336 {
337 	register struct ifaddr *ifa;
338 
339 	ifp->if_flags &= ~IFF_UP;
340 	for (ifa = ifp->if_addrlist.tqh_first; ifa != 0; ifa = ifa->ifa_list.tqe_next)
341 		pfctlinput(PRC_IFDOWN, ifa->ifa_addr);
342 	if_qflush(&ifp->if_snd);
343 	rt_ifmsg(ifp);
344 }
345 
346 /*
347  * Mark an interface up and notify protocols of
348  * the transition.
349  * NOTE: must be called at splsoftnet or equivalent.
350  */
351 void
352 if_up(ifp)
353 	register struct ifnet *ifp;
354 {
355 #ifdef notyet
356 	register struct ifaddr *ifa;
357 #endif
358 
359 	ifp->if_flags |= IFF_UP;
360 #ifdef notyet
361 	/* this has no effect on IP, and will kill all ISO connections XXX */
362 	for (ifa = ifp->if_addrlist.tqh_first; ifa != 0;
363 	     ifa = ifa->ifa_list.tqe_next)
364 		pfctlinput(PRC_IFUP, ifa->ifa_addr);
365 #endif
366 	rt_ifmsg(ifp);
367 }
368 
369 /*
370  * Flush an interface queue.
371  */
372 void
373 if_qflush(ifq)
374 	register struct ifqueue *ifq;
375 {
376 	register struct mbuf *m, *n;
377 
378 	n = ifq->ifq_head;
379 	while ((m = n) != NULL) {
380 		n = m->m_act;
381 		m_freem(m);
382 	}
383 	ifq->ifq_head = 0;
384 	ifq->ifq_tail = 0;
385 	ifq->ifq_len = 0;
386 }
387 
388 /*
389  * Handle interface watchdog timer routines.  Called
390  * from softclock, we decrement timers (if set) and
391  * call the appropriate interface routine on expiration.
392  */
393 void
394 if_slowtimo(arg)
395 	void *arg;
396 {
397 	register struct ifnet *ifp;
398 	int s = splimp();
399 
400 	for (ifp = ifnet.tqh_first; ifp != 0; ifp = ifp->if_list.tqe_next) {
401 		if (ifp->if_timer == 0 || --ifp->if_timer)
402 			continue;
403 		if (ifp->if_watchdog)
404 			(*ifp->if_watchdog)(ifp);
405 	}
406 	splx(s);
407 	timeout(if_slowtimo, NULL, hz / IFNET_SLOWHZ);
408 }
409 
410 /*
411  * Map interface name to
412  * interface structure pointer.
413  */
414 struct ifnet *
415 ifunit(name)
416 	register char *name;
417 {
418 	register struct ifnet *ifp;
419 
420 	for (ifp = ifnet.tqh_first; ifp != 0; ifp = ifp->if_list.tqe_next)
421 		if (strcmp(ifp->if_xname, name) == 0)
422 			return (ifp);
423 
424 	return (NULL);
425 }
426 
427 /*
428  * Interface ioctls.
429  */
430 int
431 ifioctl(so, cmd, data, p)
432 	struct socket *so;
433 	u_long cmd;
434 	caddr_t data;
435 	struct proc *p;
436 {
437 	register struct ifnet *ifp;
438 	register struct ifreq *ifr;
439 	int error;
440 
441 	switch (cmd) {
442 
443 	case SIOCGIFCONF:
444 	case OSIOCGIFCONF:
445 		return (ifconf(cmd, data));
446 	}
447 	ifr = (struct ifreq *)data;
448 	ifp = ifunit(ifr->ifr_name);
449 	if (ifp == 0)
450 		return (ENXIO);
451 	switch (cmd) {
452 
453 	case SIOCGIFFLAGS:
454 		ifr->ifr_flags = ifp->if_flags;
455 		break;
456 
457 	case SIOCGIFMETRIC:
458 		ifr->ifr_metric = ifp->if_metric;
459 		break;
460 
461 	case SIOCGIFMTU:
462 		ifr->ifr_mtu = ifp->if_mtu;
463 		break;
464 
465 	case SIOCSIFFLAGS:
466 		if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
467 			return (error);
468 		if (ifp->if_flags & IFF_UP && (ifr->ifr_flags & IFF_UP) == 0) {
469 			int s = splimp();
470 			if_down(ifp);
471 			splx(s);
472 		}
473 		if (ifr->ifr_flags & IFF_UP && (ifp->if_flags & IFF_UP) == 0) {
474 			int s = splimp();
475 			if_up(ifp);
476 			splx(s);
477 		}
478 		ifp->if_flags = (ifp->if_flags & IFF_CANTCHANGE) |
479 			(ifr->ifr_flags &~ IFF_CANTCHANGE);
480 		if (ifp->if_ioctl)
481 			(void) (*ifp->if_ioctl)(ifp, cmd, data);
482 		break;
483 
484 	case SIOCSIFMETRIC:
485 		if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
486 			return (error);
487 		ifp->if_metric = ifr->ifr_metric;
488 		break;
489 
490 	case SIOCSIFMTU:
491 	case SIOCADDMULTI:
492 	case SIOCDELMULTI:
493 		if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
494 			return (error);
495 		if (ifp->if_ioctl == 0)
496 			return (EOPNOTSUPP);
497 		return ((*ifp->if_ioctl)(ifp, cmd, data));
498 
499 	default:
500 		if (so->so_proto == 0)
501 			return (EOPNOTSUPP);
502 #if !defined(COMPAT_43) && !defined(COMPAT_LINUX) && !defined(COMPAT_SVR4)
503 		return ((*so->so_proto->pr_usrreq)(so, PRU_CONTROL,
504 		    (struct mbuf *)cmd, (struct mbuf *)data,
505 		    (struct mbuf *)ifp, p));
506 #else
507 	    {
508 		int ocmd = cmd;
509 
510 		switch (cmd) {
511 
512 		case SIOCSIFADDR:
513 		case SIOCSIFDSTADDR:
514 		case SIOCSIFBRDADDR:
515 		case SIOCSIFNETMASK:
516 #if BYTE_ORDER != BIG_ENDIAN
517 			if (ifr->ifr_addr.sa_family == 0 &&
518 			    ifr->ifr_addr.sa_len < 16) {
519 				ifr->ifr_addr.sa_family = ifr->ifr_addr.sa_len;
520 				ifr->ifr_addr.sa_len = 16;
521 			}
522 #else
523 			if (ifr->ifr_addr.sa_len == 0)
524 				ifr->ifr_addr.sa_len = 16;
525 #endif
526 			break;
527 
528 		case OSIOCGIFADDR:
529 			cmd = SIOCGIFADDR;
530 			break;
531 
532 		case OSIOCGIFDSTADDR:
533 			cmd = SIOCGIFDSTADDR;
534 			break;
535 
536 		case OSIOCGIFBRDADDR:
537 			cmd = SIOCGIFBRDADDR;
538 			break;
539 
540 		case OSIOCGIFNETMASK:
541 			cmd = SIOCGIFNETMASK;
542 		}
543 		error = ((*so->so_proto->pr_usrreq)(so, PRU_CONTROL,
544 		    (struct mbuf *)cmd, (struct mbuf *)data,
545 		    (struct mbuf *)ifp, p));
546 		switch (ocmd) {
547 
548 		case OSIOCGIFADDR:
549 		case OSIOCGIFDSTADDR:
550 		case OSIOCGIFBRDADDR:
551 		case OSIOCGIFNETMASK:
552 			*(u_int16_t *)&ifr->ifr_addr = ifr->ifr_addr.sa_family;
553 		}
554 		return (error);
555 
556 	    }
557 #endif
558 	}
559 	return (0);
560 }
561 
562 /*
563  * Return interface configuration
564  * of system.  List may be used
565  * in later ioctl's (above) to get
566  * other information.
567  */
568 /*ARGSUSED*/
569 int
570 ifconf(cmd, data)
571 	u_long cmd;
572 	caddr_t data;
573 {
574 	register struct ifconf *ifc = (struct ifconf *)data;
575 	register struct ifnet *ifp;
576 	register struct ifaddr *ifa;
577 	struct ifreq ifr, *ifrp;
578 	int space = ifc->ifc_len, error = 0;
579 
580 	ifrp = ifc->ifc_req;
581 	for (ifp = ifnet.tqh_first;
582 	    space >= sizeof (ifr) && ifp != 0; ifp = ifp->if_list.tqe_next) {
583 		bcopy(ifp->if_xname, ifr.ifr_name, IFNAMSIZ);
584 		if ((ifa = ifp->if_addrlist.tqh_first) == 0) {
585 			bzero((caddr_t)&ifr.ifr_addr, sizeof(ifr.ifr_addr));
586 			error = copyout((caddr_t)&ifr, (caddr_t)ifrp,
587 			    sizeof(ifr));
588 			if (error)
589 				break;
590 			space -= sizeof (ifr), ifrp++;
591 		} else
592 		    for (; space >= sizeof (ifr) && ifa != 0; ifa = ifa->ifa_list.tqe_next) {
593 			register struct sockaddr *sa = ifa->ifa_addr;
594 #if defined(COMPAT_43) || defined(COMPAT_LINUX) || defined(COMPAT_SVR4)
595 			if (cmd == OSIOCGIFCONF) {
596 				struct osockaddr *osa =
597 					 (struct osockaddr *)&ifr.ifr_addr;
598 				ifr.ifr_addr = *sa;
599 				osa->sa_family = sa->sa_family;
600 				error = copyout((caddr_t)&ifr, (caddr_t)ifrp,
601 						sizeof (ifr));
602 				ifrp++;
603 			} else
604 #endif
605 			if (sa->sa_len <= sizeof(*sa)) {
606 				ifr.ifr_addr = *sa;
607 				error = copyout((caddr_t)&ifr, (caddr_t)ifrp,
608 						sizeof (ifr));
609 				ifrp++;
610 			} else {
611 				space -= sa->sa_len - sizeof(*sa);
612 				if (space < sizeof (ifr))
613 					break;
614 				error = copyout((caddr_t)&ifr, (caddr_t)ifrp,
615 						sizeof (ifr.ifr_name));
616 				if (error == 0)
617 				    error = copyout((caddr_t)sa,
618 				      (caddr_t)&ifrp->ifr_addr, sa->sa_len);
619 				ifrp = (struct ifreq *)
620 					(sa->sa_len + (caddr_t)&ifrp->ifr_addr);
621 			}
622 			if (error)
623 				break;
624 			space -= sizeof (ifr);
625 		}
626 	}
627 	ifc->ifc_len -= space;
628 	return (error);
629 }
630