xref: /freebsd/sys/net/if_clone.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 2012 Gleb Smirnoff <glebius@FreeBSD.org>
5  * Copyright (c) 1980, 1986, 1993
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  *
32  *	@(#)if.c	8.5 (Berkeley) 1/9/95
33  * $FreeBSD$
34  */
35 
36 #include <sys/param.h>
37 #include <sys/eventhandler.h>
38 #include <sys/malloc.h>
39 #include <sys/limits.h>
40 #include <sys/lock.h>
41 #include <sys/mutex.h>
42 #include <sys/kernel.h>
43 #include <sys/systm.h>
44 #include <sys/types.h>
45 #include <sys/socket.h>
46 
47 #include <net/if.h>
48 #include <net/if_var.h>
49 #include <net/if_clone.h>
50 #include <net/radix.h>
51 #include <net/route.h>
52 #include <net/vnet.h>
53 
54 /* Current IF_MAXUNIT expands maximum to 5 characters. */
55 #define	IFCLOSIZ	(IFNAMSIZ - 5)
56 
57 /*
58  * Structure describing a `cloning' interface.
59  *
60  * List of locks
61  * (c)		const until freeing
62  * (d)		driver specific data, may need external protection.
63  * (e)		locked by if_cloners_mtx
64  * (i)		locked by ifc_mtx mtx
65  */
66 struct if_clone {
67 	char ifc_name[IFCLOSIZ];	/* (c) Name of device, e.g. `gif' */
68 	struct unrhdr *ifc_unrhdr;	/* (c) alloc_unr(9) header */
69 	int ifc_maxunit;		/* (c) maximum unit number */
70 	int ifc_flags;
71 	long ifc_refcnt;		/* (i) Reference count. */
72 	LIST_HEAD(, ifnet) ifc_iflist;	/* (i) List of cloned interfaces */
73 	struct mtx ifc_mtx;		/* Mutex to protect members. */
74 
75 	enum { SIMPLE, ADVANCED } ifc_type; /* (c) */
76 
77 	/* (c) Driver specific cloning functions.  Called with no locks held. */
78 	union {
79 		struct {	/* advanced cloner */
80 			ifc_match_t	*_ifc_match;
81 			ifc_create_t	*_ifc_create;
82 			ifc_destroy_t	*_ifc_destroy;
83 		} A;
84 		struct {	/* simple cloner */
85 			ifcs_create_t	*_ifcs_create;
86 			ifcs_destroy_t	*_ifcs_destroy;
87 			int		_ifcs_minifs;	/* minimum ifs */
88 
89 		} S;
90 	} U;
91 #define	ifc_match	U.A._ifc_match
92 #define	ifc_create	U.A._ifc_create
93 #define	ifc_destroy	U.A._ifc_destroy
94 #define	ifcs_create	U.S._ifcs_create
95 #define	ifcs_destroy	U.S._ifcs_destroy
96 #define	ifcs_minifs	U.S._ifcs_minifs
97 
98 	LIST_ENTRY(if_clone) ifc_list;	/* (e) On list of cloners */
99 };
100 
101 static void	if_clone_free(struct if_clone *ifc);
102 static int	if_clone_createif(struct if_clone *ifc, char *name, size_t len,
103 		    caddr_t params);
104 
105 static int     ifc_simple_match(struct if_clone *, const char *);
106 static int     ifc_simple_create(struct if_clone *, char *, size_t, caddr_t);
107 static int     ifc_simple_destroy(struct if_clone *, struct ifnet *);
108 
109 static struct mtx if_cloners_mtx;
110 MTX_SYSINIT(if_cloners_lock, &if_cloners_mtx, "if_cloners lock", MTX_DEF);
111 VNET_DEFINE_STATIC(int, if_cloners_count);
112 VNET_DEFINE(LIST_HEAD(, if_clone), if_cloners);
113 
114 #define	V_if_cloners_count	VNET(if_cloners_count)
115 #define	V_if_cloners		VNET(if_cloners)
116 
117 #define IF_CLONERS_LOCK_ASSERT()	mtx_assert(&if_cloners_mtx, MA_OWNED)
118 #define IF_CLONERS_LOCK()		mtx_lock(&if_cloners_mtx)
119 #define IF_CLONERS_UNLOCK()		mtx_unlock(&if_cloners_mtx)
120 
121 #define IF_CLONE_LOCK_INIT(ifc)		\
122     mtx_init(&(ifc)->ifc_mtx, "if_clone lock", NULL, MTX_DEF)
123 #define IF_CLONE_LOCK_DESTROY(ifc)	mtx_destroy(&(ifc)->ifc_mtx)
124 #define IF_CLONE_LOCK_ASSERT(ifc)	mtx_assert(&(ifc)->ifc_mtx, MA_OWNED)
125 #define IF_CLONE_LOCK(ifc)		mtx_lock(&(ifc)->ifc_mtx)
126 #define IF_CLONE_UNLOCK(ifc)		mtx_unlock(&(ifc)->ifc_mtx)
127 
128 #define IF_CLONE_ADDREF(ifc)						\
129 	do {								\
130 		IF_CLONE_LOCK(ifc);					\
131 		IF_CLONE_ADDREF_LOCKED(ifc);				\
132 		IF_CLONE_UNLOCK(ifc);					\
133 	} while (0)
134 #define IF_CLONE_ADDREF_LOCKED(ifc)					\
135 	do {								\
136 		IF_CLONE_LOCK_ASSERT(ifc);				\
137 		KASSERT((ifc)->ifc_refcnt >= 0,				\
138 		    ("negative refcnt %ld", (ifc)->ifc_refcnt));	\
139 		(ifc)->ifc_refcnt++;					\
140 	} while (0)
141 #define IF_CLONE_REMREF(ifc)						\
142 	do {								\
143 		IF_CLONE_LOCK(ifc);					\
144 		IF_CLONE_REMREF_LOCKED(ifc);				\
145 	} while (0)
146 #define IF_CLONE_REMREF_LOCKED(ifc)					\
147 	do {								\
148 		IF_CLONE_LOCK_ASSERT(ifc);				\
149 		KASSERT((ifc)->ifc_refcnt > 0,				\
150 		    ("bogus refcnt %ld", (ifc)->ifc_refcnt));		\
151 		if (--(ifc)->ifc_refcnt == 0) {				\
152 			IF_CLONE_UNLOCK(ifc);				\
153 			if_clone_free(ifc);				\
154 		} else {						\
155 			/* silently free the lock */			\
156 			IF_CLONE_UNLOCK(ifc);				\
157 		}							\
158 	} while (0)
159 
160 #define IFC_IFLIST_INSERT(_ifc, _ifp)					\
161 	LIST_INSERT_HEAD(&_ifc->ifc_iflist, _ifp, if_clones)
162 #define IFC_IFLIST_REMOVE(_ifc, _ifp)					\
163 	LIST_REMOVE(_ifp, if_clones)
164 
165 static MALLOC_DEFINE(M_CLONE, "clone", "interface cloning framework");
166 
167 void
168 vnet_if_clone_init(void)
169 {
170 
171 	LIST_INIT(&V_if_cloners);
172 }
173 
174 /*
175  * Lookup and create a clone network interface.
176  */
177 int
178 if_clone_create(char *name, size_t len, caddr_t params)
179 {
180 	struct if_clone *ifc;
181 
182 	/* Try to find an applicable cloner for this request */
183 	IF_CLONERS_LOCK();
184 	LIST_FOREACH(ifc, &V_if_cloners, ifc_list)
185 		if (ifc->ifc_type == SIMPLE) {
186 			if (ifc_simple_match(ifc, name))
187 				break;
188 		} else {
189 			if (ifc->ifc_match(ifc, name))
190 				break;
191 		}
192 #ifdef VIMAGE
193 	if (ifc == NULL && !IS_DEFAULT_VNET(curvnet)) {
194 		CURVNET_SET_QUIET(vnet0);
195 		LIST_FOREACH(ifc, &V_if_cloners, ifc_list)
196 			if (ifc->ifc_type == SIMPLE) {
197 				if (ifc_simple_match(ifc, name))
198 					break;
199 			} else {
200 				if (ifc->ifc_match(ifc, name))
201 					break;
202 			}
203 		CURVNET_RESTORE();
204 	}
205 #endif
206 	IF_CLONERS_UNLOCK();
207 
208 	if (ifc == NULL)
209 		return (EINVAL);
210 
211 	return (if_clone_createif(ifc, name, len, params));
212 }
213 
214 void
215 if_clone_addif(struct if_clone *ifc, struct ifnet *ifp)
216 {
217 
218 	if ((ifc->ifc_flags & IFC_NOGROUP) == 0)
219 		if_addgroup(ifp, ifc->ifc_name);
220 
221 	IF_CLONE_LOCK(ifc);
222 	IFC_IFLIST_INSERT(ifc, ifp);
223 	IF_CLONE_UNLOCK(ifc);
224 }
225 
226 /*
227  * Create a clone network interface.
228  */
229 static int
230 if_clone_createif(struct if_clone *ifc, char *name, size_t len, caddr_t params)
231 {
232 	int err;
233 	struct ifnet *ifp;
234 
235 	if (ifunit(name) != NULL)
236 		return (EEXIST);
237 
238 	if (ifc->ifc_type == SIMPLE)
239 		err = ifc_simple_create(ifc, name, len, params);
240 	else
241 		err = (*ifc->ifc_create)(ifc, name, len, params);
242 
243 	if (!err) {
244 		ifp = ifunit(name);
245 		if (ifp == NULL)
246 			panic("%s: lookup failed for %s", __func__, name);
247 
248 		if_clone_addif(ifc, ifp);
249 	}
250 
251 	return (err);
252 }
253 
254 /*
255  * Lookup and destroy a clone network interface.
256  */
257 int
258 if_clone_destroy(const char *name)
259 {
260 	int err;
261 	struct if_clone *ifc;
262 	struct ifnet *ifp;
263 
264 	ifp = ifunit_ref(name);
265 	if (ifp == NULL)
266 		return (ENXIO);
267 
268 	/* Find the cloner for this interface */
269 	IF_CLONERS_LOCK();
270 	LIST_FOREACH(ifc, &V_if_cloners, ifc_list) {
271 		if (strcmp(ifc->ifc_name, ifp->if_dname) == 0) {
272 			break;
273 		}
274 	}
275 #ifdef VIMAGE
276 	if (ifc == NULL && !IS_DEFAULT_VNET(curvnet)) {
277 		CURVNET_SET_QUIET(vnet0);
278 		LIST_FOREACH(ifc, &V_if_cloners, ifc_list)
279 			if (ifc->ifc_type == SIMPLE) {
280 				if (ifc_simple_match(ifc, name))
281 					break;
282 			} else {
283 				if (ifc->ifc_match(ifc, name))
284 					break;
285 			}
286 		CURVNET_RESTORE();
287 	}
288 #endif
289 	IF_CLONERS_UNLOCK();
290 	if (ifc == NULL) {
291 		if_rele(ifp);
292 		return (EINVAL);
293 	}
294 
295 	err = if_clone_destroyif(ifc, ifp);
296 	if_rele(ifp);
297 	return err;
298 }
299 
300 /*
301  * Destroy a clone network interface.
302  */
303 int
304 if_clone_destroyif(struct if_clone *ifc, struct ifnet *ifp)
305 {
306 	int err;
307 	struct ifnet *ifcifp;
308 
309 	if (ifc->ifc_type == ADVANCED && ifc->ifc_destroy == NULL)
310 		return(EOPNOTSUPP);
311 
312 	/*
313 	 * Given that the cloned ifnet might be attached to a different
314 	 * vnet from where its cloner was registered, we have to
315 	 * switch to the vnet context of the target vnet.
316 	 */
317 	CURVNET_SET_QUIET(ifp->if_vnet);
318 
319 	IF_CLONE_LOCK(ifc);
320 	LIST_FOREACH(ifcifp, &ifc->ifc_iflist, if_clones) {
321 		if (ifcifp == ifp) {
322 			IFC_IFLIST_REMOVE(ifc, ifp);
323 			break;
324 		}
325 	}
326 	IF_CLONE_UNLOCK(ifc);
327 	if (ifcifp == NULL) {
328 		CURVNET_RESTORE();
329 		return (ENXIO);		/* ifp is not on the list. */
330 	}
331 	if ((ifc->ifc_flags & IFC_NOGROUP) == 0)
332 		if_delgroup(ifp, ifc->ifc_name);
333 
334 	if (ifc->ifc_type == SIMPLE)
335 		err = ifc_simple_destroy(ifc, ifp);
336 	else
337 		err = (*ifc->ifc_destroy)(ifc, ifp);
338 
339 	if (err != 0) {
340 		if ((ifc->ifc_flags & IFC_NOGROUP) == 0)
341 			if_addgroup(ifp, ifc->ifc_name);
342 
343 		IF_CLONE_LOCK(ifc);
344 		IFC_IFLIST_INSERT(ifc, ifp);
345 		IF_CLONE_UNLOCK(ifc);
346 	}
347 	CURVNET_RESTORE();
348 	return (err);
349 }
350 
351 static struct if_clone *
352 if_clone_alloc(const char *name, int maxunit)
353 {
354 	struct if_clone *ifc;
355 
356 	KASSERT(name != NULL, ("%s: no name\n", __func__));
357 
358 	ifc = malloc(sizeof(struct if_clone), M_CLONE, M_WAITOK | M_ZERO);
359 	strncpy(ifc->ifc_name, name, IFCLOSIZ-1);
360 	IF_CLONE_LOCK_INIT(ifc);
361 	IF_CLONE_ADDREF(ifc);
362 	ifc->ifc_maxunit = maxunit ? maxunit : IF_MAXUNIT;
363 	ifc->ifc_unrhdr = new_unrhdr(0, ifc->ifc_maxunit, &ifc->ifc_mtx);
364 	LIST_INIT(&ifc->ifc_iflist);
365 
366 	return (ifc);
367 }
368 
369 static int
370 if_clone_attach(struct if_clone *ifc)
371 {
372 	struct if_clone *ifc1;
373 
374 	IF_CLONERS_LOCK();
375 	LIST_FOREACH(ifc1, &V_if_cloners, ifc_list)
376 		if (strcmp(ifc->ifc_name, ifc1->ifc_name) == 0) {
377 			IF_CLONERS_UNLOCK();
378 			IF_CLONE_REMREF(ifc);
379 			return (EEXIST);
380 		}
381 	LIST_INSERT_HEAD(&V_if_cloners, ifc, ifc_list);
382 	V_if_cloners_count++;
383 	IF_CLONERS_UNLOCK();
384 
385 	return (0);
386 }
387 
388 struct if_clone *
389 if_clone_advanced(const char *name, u_int maxunit, ifc_match_t match,
390 	ifc_create_t create, ifc_destroy_t destroy)
391 {
392 	struct if_clone *ifc;
393 
394 	ifc = if_clone_alloc(name, maxunit);
395 	ifc->ifc_type = ADVANCED;
396 	ifc->ifc_match = match;
397 	ifc->ifc_create = create;
398 	ifc->ifc_destroy = destroy;
399 
400 	if (if_clone_attach(ifc) != 0)
401 		return (NULL);
402 
403 	EVENTHANDLER_INVOKE(if_clone_event, ifc);
404 
405 	return (ifc);
406 }
407 
408 struct if_clone *
409 if_clone_simple(const char *name, ifcs_create_t create, ifcs_destroy_t destroy,
410 	u_int minifs)
411 {
412 	struct if_clone *ifc;
413 	u_int unit;
414 
415 	ifc = if_clone_alloc(name, 0);
416 	ifc->ifc_type = SIMPLE;
417 	ifc->ifcs_create = create;
418 	ifc->ifcs_destroy = destroy;
419 	ifc->ifcs_minifs = minifs;
420 
421 	if (if_clone_attach(ifc) != 0)
422 		return (NULL);
423 
424 	for (unit = 0; unit < minifs; unit++) {
425 		char name[IFNAMSIZ];
426 		int error __unused;
427 
428 		snprintf(name, IFNAMSIZ, "%s%d", ifc->ifc_name, unit);
429 		error = if_clone_createif(ifc, name, IFNAMSIZ, NULL);
430 		KASSERT(error == 0,
431 		    ("%s: failed to create required interface %s",
432 		    __func__, name));
433 	}
434 
435 	EVENTHANDLER_INVOKE(if_clone_event, ifc);
436 
437 	return (ifc);
438 }
439 
440 /*
441  * Unregister a network interface cloner.
442  */
443 void
444 if_clone_detach(struct if_clone *ifc)
445 {
446 
447 	IF_CLONERS_LOCK();
448 	LIST_REMOVE(ifc, ifc_list);
449 	V_if_cloners_count--;
450 	IF_CLONERS_UNLOCK();
451 
452 	/* Allow all simples to be destroyed */
453 	if (ifc->ifc_type == SIMPLE)
454 		ifc->ifcs_minifs = 0;
455 
456 	/* destroy all interfaces for this cloner */
457 	while (!LIST_EMPTY(&ifc->ifc_iflist))
458 		if_clone_destroyif(ifc, LIST_FIRST(&ifc->ifc_iflist));
459 
460 	IF_CLONE_REMREF(ifc);
461 }
462 
463 static void
464 if_clone_free(struct if_clone *ifc)
465 {
466 
467 	KASSERT(LIST_EMPTY(&ifc->ifc_iflist),
468 	    ("%s: ifc_iflist not empty", __func__));
469 
470 	IF_CLONE_LOCK_DESTROY(ifc);
471 	delete_unrhdr(ifc->ifc_unrhdr);
472 	free(ifc, M_CLONE);
473 }
474 
475 /*
476  * Provide list of interface cloners to userspace.
477  */
478 int
479 if_clone_list(struct if_clonereq *ifcr)
480 {
481 	char *buf, *dst, *outbuf = NULL;
482 	struct if_clone *ifc;
483 	int buf_count, count, err = 0;
484 
485 	if (ifcr->ifcr_count < 0)
486 		return (EINVAL);
487 
488 	IF_CLONERS_LOCK();
489 	/*
490 	 * Set our internal output buffer size.  We could end up not
491 	 * reporting a cloner that is added between the unlock and lock
492 	 * below, but that's not a major problem.  Not caping our
493 	 * allocation to the number of cloners actually in the system
494 	 * could be because that would let arbitrary users cause us to
495 	 * allocate arbitrary amounts of kernel memory.
496 	 */
497 	buf_count = (V_if_cloners_count < ifcr->ifcr_count) ?
498 	    V_if_cloners_count : ifcr->ifcr_count;
499 	IF_CLONERS_UNLOCK();
500 
501 	outbuf = malloc(IFNAMSIZ*buf_count, M_CLONE, M_WAITOK | M_ZERO);
502 
503 	IF_CLONERS_LOCK();
504 
505 	ifcr->ifcr_total = V_if_cloners_count;
506 	if ((dst = ifcr->ifcr_buffer) == NULL) {
507 		/* Just asking how many there are. */
508 		goto done;
509 	}
510 	count = (V_if_cloners_count < buf_count) ?
511 	    V_if_cloners_count : buf_count;
512 
513 	for (ifc = LIST_FIRST(&V_if_cloners), buf = outbuf;
514 	    ifc != NULL && count != 0;
515 	    ifc = LIST_NEXT(ifc, ifc_list), count--, buf += IFNAMSIZ) {
516 		strlcpy(buf, ifc->ifc_name, IFNAMSIZ);
517 	}
518 
519 done:
520 	IF_CLONERS_UNLOCK();
521 	if (err == 0 && dst != NULL)
522 		err = copyout(outbuf, dst, buf_count*IFNAMSIZ);
523 	if (outbuf != NULL)
524 		free(outbuf, M_CLONE);
525 	return (err);
526 }
527 
528 /*
529  * if_clone_findifc() looks up ifnet from the current
530  * cloner list, and returns ifc if found.  Note that ifc_refcnt
531  * is incremented.
532  */
533 struct if_clone *
534 if_clone_findifc(struct ifnet *ifp)
535 {
536 	struct if_clone *ifc, *ifc0;
537 	struct ifnet *ifcifp;
538 
539 	ifc0 = NULL;
540 	IF_CLONERS_LOCK();
541 	LIST_FOREACH(ifc, &V_if_cloners, ifc_list) {
542 		IF_CLONE_LOCK(ifc);
543 		LIST_FOREACH(ifcifp, &ifc->ifc_iflist, if_clones) {
544 			if (ifp == ifcifp) {
545 				ifc0 = ifc;
546 				IF_CLONE_ADDREF_LOCKED(ifc);
547 				break;
548 			}
549 		}
550 		IF_CLONE_UNLOCK(ifc);
551 		if (ifc0 != NULL)
552 			break;
553 	}
554 	IF_CLONERS_UNLOCK();
555 
556 	return (ifc0);
557 }
558 
559 /*
560  * if_clone_addgroup() decrements ifc_refcnt because it is called after
561  * if_clone_findifc().
562  */
563 void
564 if_clone_addgroup(struct ifnet *ifp, struct if_clone *ifc)
565 {
566 	if ((ifc->ifc_flags & IFC_NOGROUP) == 0) {
567 		if_addgroup(ifp, ifc->ifc_name);
568 		IF_CLONE_REMREF(ifc);
569 	}
570 }
571 
572 /*
573  * A utility function to extract unit numbers from interface names of
574  * the form name###.
575  *
576  * Returns 0 on success and an error on failure.
577  */
578 int
579 ifc_name2unit(const char *name, int *unit)
580 {
581 	const char	*cp;
582 	int		cutoff = INT_MAX / 10;
583 	int		cutlim = INT_MAX % 10;
584 
585 	for (cp = name; *cp != '\0' && (*cp < '0' || *cp > '9'); cp++)
586 		;
587 	if (*cp == '\0') {
588 		*unit = -1;
589 	} else if (cp[0] == '0' && cp[1] != '\0') {
590 		/* Disallow leading zeroes. */
591 		return (EINVAL);
592 	} else {
593 		for (*unit = 0; *cp != '\0'; cp++) {
594 			if (*cp < '0' || *cp > '9') {
595 				/* Bogus unit number. */
596 				return (EINVAL);
597 			}
598 			if (*unit > cutoff ||
599 			    (*unit == cutoff && *cp - '0' > cutlim))
600 				return (EINVAL);
601 			*unit = (*unit * 10) + (*cp - '0');
602 		}
603 	}
604 
605 	return (0);
606 }
607 
608 static int
609 ifc_alloc_unit_specific(struct if_clone *ifc, int *unit)
610 {
611 	char name[IFNAMSIZ];
612 
613 	if (*unit > ifc->ifc_maxunit)
614 		return (ENOSPC);
615 
616 	if (alloc_unr_specific(ifc->ifc_unrhdr, *unit) == -1)
617 		return (EEXIST);
618 
619 	snprintf(name, IFNAMSIZ, "%s%d", ifc->ifc_name, *unit);
620 	if (ifunit(name) != NULL) {
621 		free_unr(ifc->ifc_unrhdr, *unit);
622 		return (EEXIST);
623 	}
624 
625 	IF_CLONE_ADDREF(ifc);
626 
627 	return (0);
628 }
629 
630 static int
631 ifc_alloc_unit_next(struct if_clone *ifc, int *unit)
632 {
633 	int error;
634 
635 	*unit = alloc_unr(ifc->ifc_unrhdr);
636 	if (*unit == -1)
637 		return (ENOSPC);
638 
639 	free_unr(ifc->ifc_unrhdr, *unit);
640 	for (;;) {
641 		error = ifc_alloc_unit_specific(ifc, unit);
642 		if (error != EEXIST)
643 			break;
644 
645 		(*unit)++;
646 	}
647 
648 	return (error);
649 }
650 
651 int
652 ifc_alloc_unit(struct if_clone *ifc, int *unit)
653 {
654 	if (*unit < 0)
655 		return (ifc_alloc_unit_next(ifc, unit));
656 	else
657 		return (ifc_alloc_unit_specific(ifc, unit));
658 }
659 
660 void
661 ifc_free_unit(struct if_clone *ifc, int unit)
662 {
663 
664 	free_unr(ifc->ifc_unrhdr, unit);
665 	IF_CLONE_REMREF(ifc);
666 }
667 
668 static int
669 ifc_simple_match(struct if_clone *ifc, const char *name)
670 {
671 	const char *cp;
672 	int i;
673 
674 	/* Match the name */
675 	for (cp = name, i = 0; i < strlen(ifc->ifc_name); i++, cp++) {
676 		if (ifc->ifc_name[i] != *cp)
677 			return (0);
678 	}
679 
680 	/* Make sure there's a unit number or nothing after the name */
681 	for (; *cp != '\0'; cp++) {
682 		if (*cp < '0' || *cp > '9')
683 			return (0);
684 	}
685 
686 	return (1);
687 }
688 
689 static int
690 ifc_simple_create(struct if_clone *ifc, char *name, size_t len, caddr_t params)
691 {
692 	char *dp;
693 	int wildcard;
694 	int unit;
695 	int err;
696 
697 	err = ifc_name2unit(name, &unit);
698 	if (err != 0)
699 		return (err);
700 
701 	wildcard = (unit < 0);
702 
703 	err = ifc_alloc_unit(ifc, &unit);
704 	if (err != 0)
705 		return (err);
706 
707 	err = ifc->ifcs_create(ifc, unit, params);
708 	if (err != 0) {
709 		ifc_free_unit(ifc, unit);
710 		return (err);
711 	}
712 
713 	/* In the wildcard case, we need to update the name. */
714 	if (wildcard) {
715 		for (dp = name; *dp != '\0'; dp++);
716 		if (snprintf(dp, len - (dp-name), "%d", unit) >
717 		    len - (dp-name) - 1) {
718 			/*
719 			 * This can only be a programmer error and
720 			 * there's no straightforward way to recover if
721 			 * it happens.
722 			 */
723 			panic("if_clone_create(): interface name too long");
724 		}
725 	}
726 
727 	return (0);
728 }
729 
730 static int
731 ifc_simple_destroy(struct if_clone *ifc, struct ifnet *ifp)
732 {
733 	int unit;
734 
735 	unit = ifp->if_dunit;
736 
737 	if (unit < ifc->ifcs_minifs)
738 		return (EINVAL);
739 
740 	ifc->ifcs_destroy(ifp);
741 
742 	ifc_free_unit(ifc, unit);
743 
744 	return (0);
745 }
746 
747 const char *
748 ifc_name(struct if_clone *ifc)
749 {
750 	return (ifc->ifc_name);
751 }
752 
753 void
754 ifc_flags_set(struct if_clone *ifc, int flags)
755 {
756 	ifc->ifc_flags = flags;
757 }
758 
759 int
760 ifc_flags_get(struct if_clone *ifc)
761 {
762 	return (ifc->ifc_flags);
763 }
764