xref: /netbsd-src/sys/net/if.c (revision 1f2744e6e4915c9da2a3f980279398c4cf7d5e6d)
1 /*	$NetBSD: if.c,v 1.19 1995/03/09 09:47:25 mycroft 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 
52 int	ifqmaxlen = IFQ_MAXLEN;
53 void	if_slowtimo __P((void *arg));
54 
55 /*
56  * Network interface utility routines.
57  *
58  * Routines with ifa_ifwith* names take sockaddr *'s as
59  * parameters.
60  */
61 void
62 ifinit()
63 {
64 	register struct ifnet *ifp;
65 
66 	for (ifp = ifnet; ifp; ifp = ifp->if_next)
67 		if (ifp->if_snd.ifq_maxlen == 0)
68 			ifp->if_snd.ifq_maxlen = ifqmaxlen;
69 	if_slowtimo(NULL);
70 }
71 
72 int if_index = 0;
73 struct ifaddr **ifnet_addrs;
74 static char *sprint_d __P((u_int, char *, int));
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, unitlen, masklen;
86 	char workbuf[12], *unitname;
87 	register struct ifnet **p = &ifnet;
88 	register struct sockaddr_dl *sdl;
89 	register struct ifaddr *ifa;
90 	static int if_indexlim = 8;
91 	extern void link_rtrequest();
92 
93 	while (*p)
94 		p = &((*p)->if_next);
95 	*p = ifp;
96 	ifp->if_index = ++if_index;
97 	if (ifnet_addrs == 0 || if_index >= if_indexlim) {
98 		unsigned n = (if_indexlim <<= 1) * sizeof(ifa);
99 		struct ifaddr **q = (struct ifaddr **)
100 					malloc(n, M_IFADDR, M_WAITOK);
101 		if (ifnet_addrs) {
102 			bcopy((caddr_t)ifnet_addrs, (caddr_t)q, n/2);
103 			free((caddr_t)ifnet_addrs, M_IFADDR);
104 		}
105 		ifnet_addrs = q;
106 	}
107 	/*
108 	 * create a Link Level name for this device
109 	 */
110 	unitname = sprint_d((u_int)ifp->if_unit, workbuf, sizeof(workbuf));
111 	namelen = strlen(ifp->if_name);
112 	unitlen = strlen(unitname);
113 #define _offsetof(t, m) ((int)((caddr_t)&((t *)0)->m))
114 	masklen = _offsetof(struct sockaddr_dl, sdl_data[0]) +
115 			       unitlen + namelen;
116 	socksize = masklen + ifp->if_addrlen;
117 #define ROUNDUP(a) (1 + (((a) - 1) | (sizeof(long) - 1)))
118 	socksize = ROUNDUP(socksize);
119 	if (socksize < sizeof(*sdl))
120 		socksize = sizeof(*sdl);
121 	ifasize = sizeof(*ifa) + 2 * socksize;
122 	ifa = (struct ifaddr *)malloc(ifasize, M_IFADDR, M_WAITOK);
123 	if (ifa == 0)
124 		return;
125 	bzero((caddr_t)ifa, ifasize);
126 	sdl = (struct sockaddr_dl *)(ifa + 1);
127 	sdl->sdl_len = socksize;
128 	sdl->sdl_family = AF_LINK;
129 	bcopy(ifp->if_name, sdl->sdl_data, namelen);
130 	bcopy(unitname, namelen + (caddr_t)sdl->sdl_data, unitlen);
131 	sdl->sdl_nlen = (namelen += unitlen);
132 	sdl->sdl_index = ifp->if_index;
133 	sdl->sdl_type = ifp->if_type;
134 	ifnet_addrs[if_index - 1] = ifa;
135 	ifa->ifa_ifp = ifp;
136 	ifa->ifa_next = ifp->if_addrlist;
137 	ifa->ifa_rtrequest = link_rtrequest;
138 	ifp->if_addrlist = ifa;
139 	ifa->ifa_addr = (struct sockaddr *)sdl;
140 	sdl = (struct sockaddr_dl *)(socksize + (caddr_t)sdl);
141 	ifa->ifa_netmask = (struct sockaddr *)sdl;
142 	sdl->sdl_len = masklen;
143 	while (namelen != 0)
144 		sdl->sdl_data[--namelen] = 0xff;
145 }
146 /*
147  * Locate an interface based on a complete address.
148  */
149 /*ARGSUSED*/
150 struct ifaddr *
151 ifa_ifwithaddr(addr)
152 	register struct sockaddr *addr;
153 {
154 	register struct ifnet *ifp;
155 	register struct ifaddr *ifa;
156 
157 #define	equal(a1, a2) \
158   (bcmp((caddr_t)(a1), (caddr_t)(a2), ((struct sockaddr *)(a1))->sa_len) == 0)
159 	for (ifp = ifnet; ifp; ifp = ifp->if_next)
160 	    for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next) {
161 		if (ifa->ifa_addr->sa_family != addr->sa_family)
162 			continue;
163 		if (equal(addr, ifa->ifa_addr))
164 			return (ifa);
165 		if ((ifp->if_flags & IFF_BROADCAST) && ifa->ifa_broadaddr &&
166 		    equal(ifa->ifa_broadaddr, addr))
167 			return (ifa);
168 	}
169 	return ((struct ifaddr *)0);
170 }
171 /*
172  * Locate the point to point interface with a given destination address.
173  */
174 /*ARGSUSED*/
175 struct ifaddr *
176 ifa_ifwithdstaddr(addr)
177 	register struct sockaddr *addr;
178 {
179 	register struct ifnet *ifp;
180 	register struct ifaddr *ifa;
181 
182 	for (ifp = ifnet; ifp; ifp = ifp->if_next)
183 	    if (ifp->if_flags & IFF_POINTOPOINT)
184 		for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next) {
185 			if (ifa->ifa_addr->sa_family != addr->sa_family)
186 				continue;
187 			if (equal(addr, ifa->ifa_dstaddr))
188 				return (ifa);
189 	}
190 	return ((struct ifaddr *)0);
191 }
192 
193 /*
194  * Find an interface on a specific network.  If many, choice
195  * is most specific found.
196  */
197 struct ifaddr *
198 ifa_ifwithnet(addr)
199 	struct sockaddr *addr;
200 {
201 	register struct ifnet *ifp;
202 	register struct ifaddr *ifa;
203 	struct ifaddr *ifa_maybe = 0;
204 	u_int af = addr->sa_family;
205 	char *addr_data = addr->sa_data, *cplim;
206 
207 	if (af == AF_LINK) {
208 	    register struct sockaddr_dl *sdl = (struct sockaddr_dl *)addr;
209 	    if (sdl->sdl_index && sdl->sdl_index <= if_index)
210 		return (ifnet_addrs[sdl->sdl_index - 1]);
211 	}
212 	for (ifp = ifnet; ifp; ifp = ifp->if_next)
213 		for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next) {
214 			register char *cp, *cp2, *cp3;
215 
216 			if (ifa->ifa_addr->sa_family != af ||
217 			    ifa->ifa_netmask == 0)
218 				next: continue;
219 			cp = addr_data;
220 			cp2 = ifa->ifa_addr->sa_data;
221 			cp3 = ifa->ifa_netmask->sa_data;
222 			cplim = (char *)ifa->ifa_netmask +
223 				ifa->ifa_netmask->sa_len;
224 			while (cp3 < cplim)
225 				if ((*cp++ ^ *cp2++) & *cp3++)
226 					goto next;
227 			if (ifa_maybe == 0 ||
228 			    rn_refines((caddr_t)ifa->ifa_netmask,
229 			    (caddr_t)ifa_maybe->ifa_netmask))
230 				ifa_maybe = ifa;
231 		}
232 	return (ifa_maybe);
233 }
234 
235 /*
236  * Find an interface using a specific address family
237  */
238 struct ifaddr *
239 ifa_ifwithaf(af)
240 	register int af;
241 {
242 	register struct ifnet *ifp;
243 	register struct ifaddr *ifa;
244 
245 	for (ifp = ifnet; ifp; ifp = ifp->if_next)
246 	    for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next)
247 		if (ifa->ifa_addr->sa_family == af)
248 			return (ifa);
249 	return ((struct ifaddr *)0);
250 }
251 
252 /*
253  * Find an interface address specific to an interface best matching
254  * a given address.
255  */
256 struct ifaddr *
257 ifaof_ifpforaddr(addr, ifp)
258 	struct sockaddr *addr;
259 	register struct ifnet *ifp;
260 {
261 	register struct ifaddr *ifa;
262 	register char *cp, *cp2, *cp3;
263 	register char *cplim;
264 	struct ifaddr *ifa_maybe = 0;
265 	u_int af = addr->sa_family;
266 
267 	if (af >= AF_MAX)
268 		return (0);
269 	for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next) {
270 		if (ifa->ifa_addr->sa_family != af)
271 			continue;
272 		ifa_maybe = ifa;
273 		if (ifa->ifa_netmask == 0) {
274 			if (equal(addr, ifa->ifa_addr) ||
275 			    (ifa->ifa_dstaddr && equal(addr, ifa->ifa_dstaddr)))
276 				return (ifa);
277 			continue;
278 		}
279 		cp = addr->sa_data;
280 		cp2 = ifa->ifa_addr->sa_data;
281 		cp3 = ifa->ifa_netmask->sa_data;
282 		cplim = ifa->ifa_netmask->sa_len + (char *)ifa->ifa_netmask;
283 		for (; cp3 < cplim; cp3++)
284 			if ((*cp++ ^ *cp2++) & *cp3)
285 				break;
286 		if (cp3 == cplim)
287 			return (ifa);
288 	}
289 	return (ifa_maybe);
290 }
291 
292 #include <net/route.h>
293 
294 /*
295  * Default action when installing a route with a Link Level gateway.
296  * Lookup an appropriate real ifa to point to.
297  * This should be moved to /sys/net/link.c eventually.
298  */
299 void
300 link_rtrequest(cmd, rt, sa)
301 	int cmd;
302 	register struct rtentry *rt;
303 	struct sockaddr *sa;
304 {
305 	register struct ifaddr *ifa;
306 	struct sockaddr *dst;
307 	struct ifnet *ifp;
308 
309 	if (cmd != RTM_ADD || ((ifa = rt->rt_ifa) == 0) ||
310 	    ((ifp = ifa->ifa_ifp) == 0) || ((dst = rt_key(rt)) == 0))
311 		return;
312 	if (ifa = ifaof_ifpforaddr(dst, ifp)) {
313 		IFAFREE(rt->rt_ifa);
314 		rt->rt_ifa = ifa;
315 		ifa->ifa_refcnt++;
316 		if (ifa->ifa_rtrequest && ifa->ifa_rtrequest != link_rtrequest)
317 			ifa->ifa_rtrequest(cmd, rt, sa);
318 	}
319 }
320 
321 /*
322  * Mark an interface down and notify protocols of
323  * the transition.
324  * NOTE: must be called at splnet or eqivalent.
325  */
326 void
327 if_down(ifp)
328 	register struct ifnet *ifp;
329 {
330 	register struct ifaddr *ifa;
331 
332 	ifp->if_flags &= ~IFF_UP;
333 	for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next)
334 		pfctlinput(PRC_IFDOWN, ifa->ifa_addr);
335 	if_qflush(&ifp->if_snd);
336 	rt_ifmsg(ifp);
337 }
338 
339 /*
340  * Mark an interface up and notify protocols of
341  * the transition.
342  * NOTE: must be called at splnet or equivalent.
343  */
344 void
345 if_up(ifp)
346 	register struct ifnet *ifp;
347 {
348 	register struct ifaddr *ifa;
349 
350 	ifp->if_flags |= IFF_UP;
351 #ifdef notyet
352 	/* this has no effect on IP, and will kill all ISO connections XXX */
353 	for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next)
354 		pfctlinput(PRC_IFUP, ifa->ifa_addr);
355 #endif
356 	rt_ifmsg(ifp);
357 }
358 
359 /*
360  * Flush an interface queue.
361  */
362 void
363 if_qflush(ifq)
364 	register struct ifqueue *ifq;
365 {
366 	register struct mbuf *m, *n;
367 
368 	n = ifq->ifq_head;
369 	while (m = n) {
370 		n = m->m_act;
371 		m_freem(m);
372 	}
373 	ifq->ifq_head = 0;
374 	ifq->ifq_tail = 0;
375 	ifq->ifq_len = 0;
376 }
377 
378 /*
379  * Handle interface watchdog timer routines.  Called
380  * from softclock, we decrement timers (if set) and
381  * call the appropriate interface routine on expiration.
382  */
383 void
384 if_slowtimo(arg)
385 	void *arg;
386 {
387 	register struct ifnet *ifp;
388 	int s = splimp();
389 
390 	for (ifp = ifnet; ifp; ifp = ifp->if_next) {
391 		if (ifp->if_timer == 0 || --ifp->if_timer)
392 			continue;
393 		if (ifp->if_watchdog)
394 			(*ifp->if_watchdog)(ifp->if_unit);
395 	}
396 	splx(s);
397 	timeout(if_slowtimo, NULL, hz / IFNET_SLOWHZ);
398 }
399 
400 /*
401  * Map interface name to
402  * interface structure pointer.
403  */
404 struct ifnet *
405 ifunit(name)
406 	register char *name;
407 {
408 	register char *cp;
409 	register struct ifnet *ifp;
410 	int unit;
411 	unsigned len;
412 	char *ep, c;
413 
414 	for (cp = name; cp < name + IFNAMSIZ && *cp; cp++)
415 		if (*cp >= '0' && *cp <= '9')
416 			break;
417 	if (*cp == '\0' || cp == name + IFNAMSIZ)
418 		return ((struct ifnet *)0);
419 	/*
420 	 * Save first char of unit, and pointer to it,
421 	 * so we can put a null there to avoid matching
422 	 * initial substrings of interface names.
423 	 */
424 	len = cp - name + 1;
425 	c = *cp;
426 	ep = cp;
427 	for (unit = 0; *cp >= '0' && *cp <= '9'; )
428 		unit = unit * 10 + *cp++ - '0';
429 	*ep = 0;
430 	for (ifp = ifnet; ifp; ifp = ifp->if_next) {
431 		if (bcmp(ifp->if_name, name, len))
432 			continue;
433 		if (unit == ifp->if_unit)
434 			break;
435 	}
436 	*ep = c;
437 	return (ifp);
438 }
439 
440 /*
441  * Interface ioctls.
442  */
443 int
444 ifioctl(so, cmd, data, p)
445 	struct socket *so;
446 	u_long cmd;
447 	caddr_t data;
448 	struct proc *p;
449 {
450 	register struct ifnet *ifp;
451 	register struct ifreq *ifr;
452 	int error;
453 
454 	switch (cmd) {
455 
456 	case SIOCGIFCONF:
457 	case OSIOCGIFCONF:
458 		return (ifconf(cmd, data));
459 	}
460 	ifr = (struct ifreq *)data;
461 	ifp = ifunit(ifr->ifr_name);
462 	if (ifp == 0)
463 		return (ENXIO);
464 	switch (cmd) {
465 
466 	case SIOCGIFFLAGS:
467 		ifr->ifr_flags = ifp->if_flags;
468 		break;
469 
470 	case SIOCGIFMETRIC:
471 		ifr->ifr_metric = ifp->if_metric;
472 		break;
473 
474 	case SIOCSIFFLAGS:
475 		if (error = suser(p->p_ucred, &p->p_acflag))
476 			return (error);
477 		if (ifp->if_flags & IFF_UP && (ifr->ifr_flags & IFF_UP) == 0) {
478 			int s = splimp();
479 			if_down(ifp);
480 			splx(s);
481 		}
482 		if (ifr->ifr_flags & IFF_UP && (ifp->if_flags & IFF_UP) == 0) {
483 			int s = splimp();
484 			if_up(ifp);
485 			splx(s);
486 		}
487 		ifp->if_flags = (ifp->if_flags & IFF_CANTCHANGE) |
488 			(ifr->ifr_flags &~ IFF_CANTCHANGE);
489 		if (ifp->if_ioctl)
490 			(void) (*ifp->if_ioctl)(ifp, cmd, data);
491 		break;
492 
493 	case SIOCSIFMETRIC:
494 		if (error = suser(p->p_ucred, &p->p_acflag))
495 			return (error);
496 		ifp->if_metric = ifr->ifr_metric;
497 		break;
498 
499 	case SIOCADDMULTI:
500 	case SIOCDELMULTI:
501 		if (error = suser(p->p_ucred, &p->p_acflag))
502 			return (error);
503 		if (ifp->if_ioctl == 0)
504 			return (EOPNOTSUPP);
505 		return ((*ifp->if_ioctl)(ifp, cmd, data));
506 
507 	default:
508 		if (so->so_proto == 0)
509 			return (EOPNOTSUPP);
510 #ifndef COMPAT_43
511 		return ((*so->so_proto->pr_usrreq)(so, PRU_CONTROL,
512 			cmd, data, ifp));
513 #else
514 	    {
515 		int ocmd = cmd;
516 
517 		switch (cmd) {
518 
519 		case SIOCSIFDSTADDR:
520 		case SIOCSIFADDR:
521 		case SIOCSIFBRDADDR:
522 		case SIOCSIFNETMASK:
523 #if BYTE_ORDER != BIG_ENDIAN
524 			if (ifr->ifr_addr.sa_family == 0 &&
525 			    ifr->ifr_addr.sa_len < 16) {
526 				ifr->ifr_addr.sa_family = ifr->ifr_addr.sa_len;
527 				ifr->ifr_addr.sa_len = 16;
528 			}
529 #else
530 			if (ifr->ifr_addr.sa_len == 0)
531 				ifr->ifr_addr.sa_len = 16;
532 #endif
533 			break;
534 
535 		case OSIOCGIFADDR:
536 			cmd = SIOCGIFADDR;
537 			break;
538 
539 		case OSIOCGIFDSTADDR:
540 			cmd = SIOCGIFDSTADDR;
541 			break;
542 
543 		case OSIOCGIFBRDADDR:
544 			cmd = SIOCGIFBRDADDR;
545 			break;
546 
547 		case OSIOCGIFNETMASK:
548 			cmd = SIOCGIFNETMASK;
549 		}
550 		error =  ((*so->so_proto->pr_usrreq)(so, PRU_CONTROL,
551 							    cmd, data, ifp));
552 		switch (ocmd) {
553 
554 		case OSIOCGIFADDR:
555 		case OSIOCGIFDSTADDR:
556 		case OSIOCGIFBRDADDR:
557 		case OSIOCGIFNETMASK:
558 			*(u_short *)&ifr->ifr_addr = ifr->ifr_addr.sa_family;
559 		}
560 		return (error);
561 
562 	    }
563 #endif
564 	}
565 	return (0);
566 }
567 
568 /*
569  * Return interface configuration
570  * of system.  List may be used
571  * in later ioctl's (above) to get
572  * other information.
573  */
574 /*ARGSUSED*/
575 int
576 ifconf(cmd, data)
577 	u_long cmd;
578 	caddr_t data;
579 {
580 	register struct ifconf *ifc = (struct ifconf *)data;
581 	register struct ifnet *ifp = ifnet;
582 	register struct ifaddr *ifa;
583 	register char *cp, *ep;
584 	struct ifreq ifr, *ifrp;
585 	int space = ifc->ifc_len, error = 0;
586 
587 	ifrp = ifc->ifc_req;
588 	ep = ifr.ifr_name + sizeof (ifr.ifr_name) - 2;
589 	for (; space > sizeof (ifr) && ifp; ifp = ifp->if_next) {
590 		strncpy(ifr.ifr_name, ifp->if_name, sizeof(ifr.ifr_name) - 2);
591 		for (cp = ifr.ifr_name; cp < ep && *cp; cp++)
592 			continue;
593 		*cp++ = '0' + ifp->if_unit; *cp = '\0';
594 		if ((ifa = ifp->if_addrlist) == 0) {
595 			bzero((caddr_t)&ifr.ifr_addr, sizeof(ifr.ifr_addr));
596 			error = copyout((caddr_t)&ifr, (caddr_t)ifrp,
597 			    sizeof(ifr));
598 			if (error)
599 				break;
600 			space -= sizeof (ifr), ifrp++;
601 		} else
602 		    for ( ; space > sizeof (ifr) && ifa; ifa = ifa->ifa_next) {
603 			register struct sockaddr *sa = ifa->ifa_addr;
604 #ifdef COMPAT_43
605 			if (cmd == OSIOCGIFCONF) {
606 				struct osockaddr *osa =
607 					 (struct osockaddr *)&ifr.ifr_addr;
608 				ifr.ifr_addr = *sa;
609 				osa->sa_family = sa->sa_family;
610 				error = copyout((caddr_t)&ifr, (caddr_t)ifrp,
611 						sizeof (ifr));
612 				ifrp++;
613 			} else
614 #endif
615 			if (sa->sa_len <= sizeof(*sa)) {
616 				ifr.ifr_addr = *sa;
617 				error = copyout((caddr_t)&ifr, (caddr_t)ifrp,
618 						sizeof (ifr));
619 				ifrp++;
620 			} else {
621 				space -= sa->sa_len - sizeof(*sa);
622 				if (space < sizeof (ifr))
623 					break;
624 				error = copyout((caddr_t)&ifr, (caddr_t)ifrp,
625 						sizeof (ifr.ifr_name));
626 				if (error == 0)
627 				    error = copyout((caddr_t)sa,
628 				      (caddr_t)&ifrp->ifr_addr, sa->sa_len);
629 				ifrp = (struct ifreq *)
630 					(sa->sa_len + (caddr_t)&ifrp->ifr_addr);
631 			}
632 			if (error)
633 				break;
634 			space -= sizeof (ifr);
635 		}
636 	}
637 	ifc->ifc_len -= space;
638 	return (error);
639 }
640 
641 static char *
642 sprint_d(n, buf, buflen)
643 	u_int n;
644 	char *buf;
645 	int buflen;
646 {
647 	register char *cp = buf + buflen - 1;
648 
649 	*cp = 0;
650 	do {
651 		cp--;
652 		*cp = "0123456789"[n % 10];
653 		n /= 10;
654 	} while (n != 0);
655 	return (cp);
656 }
657