xref: /freebsd/sys/net/if_clone.c (revision b9f654b163bce26de79705e77b872427c9f2afa1)
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 /*
215  * Create a clone network interface.
216  */
217 static int
218 if_clone_createif(struct if_clone *ifc, char *name, size_t len, caddr_t params)
219 {
220 	int err;
221 	struct ifnet *ifp;
222 
223 	if (ifunit(name) != NULL)
224 		return (EEXIST);
225 
226 	if (ifc->ifc_type == SIMPLE)
227 		err = ifc_simple_create(ifc, name, len, params);
228 	else
229 		err = (*ifc->ifc_create)(ifc, name, len, params);
230 
231 	if (!err) {
232 		ifp = ifunit(name);
233 		if (ifp == NULL)
234 			panic("%s: lookup failed for %s", __func__, name);
235 
236 		if ((ifc->ifc_flags & IFC_NOGROUP) == 0)
237 			if_addgroup(ifp, ifc->ifc_name);
238 
239 		IF_CLONE_LOCK(ifc);
240 		IFC_IFLIST_INSERT(ifc, ifp);
241 		IF_CLONE_UNLOCK(ifc);
242 	}
243 
244 	return (err);
245 }
246 
247 /*
248  * Lookup and destroy a clone network interface.
249  */
250 int
251 if_clone_destroy(const char *name)
252 {
253 	int err;
254 	struct if_clone *ifc;
255 	struct ifnet *ifp;
256 
257 	ifp = ifunit_ref(name);
258 	if (ifp == NULL)
259 		return (ENXIO);
260 
261 	/* Find the cloner for this interface */
262 	IF_CLONERS_LOCK();
263 	LIST_FOREACH(ifc, &V_if_cloners, ifc_list) {
264 		if (strcmp(ifc->ifc_name, ifp->if_dname) == 0) {
265 			break;
266 		}
267 	}
268 #ifdef VIMAGE
269 	if (ifc == NULL && !IS_DEFAULT_VNET(curvnet)) {
270 		CURVNET_SET_QUIET(vnet0);
271 		LIST_FOREACH(ifc, &V_if_cloners, ifc_list)
272 			if (ifc->ifc_type == SIMPLE) {
273 				if (ifc_simple_match(ifc, name))
274 					break;
275 			} else {
276 				if (ifc->ifc_match(ifc, name))
277 					break;
278 			}
279 		CURVNET_RESTORE();
280 	}
281 #endif
282 	IF_CLONERS_UNLOCK();
283 	if (ifc == NULL) {
284 		if_rele(ifp);
285 		return (EINVAL);
286 	}
287 
288 	err = if_clone_destroyif(ifc, ifp);
289 	if_rele(ifp);
290 	return err;
291 }
292 
293 /*
294  * Destroy a clone network interface.
295  */
296 int
297 if_clone_destroyif(struct if_clone *ifc, struct ifnet *ifp)
298 {
299 	int err;
300 	struct ifnet *ifcifp;
301 
302 	if (ifc->ifc_type == ADVANCED && ifc->ifc_destroy == NULL)
303 		return(EOPNOTSUPP);
304 
305 	/*
306 	 * Given that the cloned ifnet might be attached to a different
307 	 * vnet from where its cloner was registered, we have to
308 	 * switch to the vnet context of the target vnet.
309 	 */
310 	CURVNET_SET_QUIET(ifp->if_vnet);
311 
312 	IF_CLONE_LOCK(ifc);
313 	LIST_FOREACH(ifcifp, &ifc->ifc_iflist, if_clones) {
314 		if (ifcifp == ifp) {
315 			IFC_IFLIST_REMOVE(ifc, ifp);
316 			break;
317 		}
318 	}
319 	IF_CLONE_UNLOCK(ifc);
320 	if (ifcifp == NULL) {
321 		CURVNET_RESTORE();
322 		return (ENXIO);		/* ifp is not on the list. */
323 	}
324 	if ((ifc->ifc_flags & IFC_NOGROUP) == 0)
325 		if_delgroup(ifp, ifc->ifc_name);
326 
327 	if (ifc->ifc_type == SIMPLE)
328 		err = ifc_simple_destroy(ifc, ifp);
329 	else
330 		err = (*ifc->ifc_destroy)(ifc, ifp);
331 
332 	if (err != 0) {
333 		if ((ifc->ifc_flags & IFC_NOGROUP) == 0)
334 			if_addgroup(ifp, ifc->ifc_name);
335 
336 		IF_CLONE_LOCK(ifc);
337 		IFC_IFLIST_INSERT(ifc, ifp);
338 		IF_CLONE_UNLOCK(ifc);
339 	}
340 	CURVNET_RESTORE();
341 	return (err);
342 }
343 
344 static struct if_clone *
345 if_clone_alloc(const char *name, int maxunit)
346 {
347 	struct if_clone *ifc;
348 
349 	KASSERT(name != NULL, ("%s: no name\n", __func__));
350 
351 	ifc = malloc(sizeof(struct if_clone), M_CLONE, M_WAITOK | M_ZERO);
352 	strncpy(ifc->ifc_name, name, IFCLOSIZ-1);
353 	IF_CLONE_LOCK_INIT(ifc);
354 	IF_CLONE_ADDREF(ifc);
355 	ifc->ifc_maxunit = maxunit ? maxunit : IF_MAXUNIT;
356 	ifc->ifc_unrhdr = new_unrhdr(0, ifc->ifc_maxunit, &ifc->ifc_mtx);
357 	LIST_INIT(&ifc->ifc_iflist);
358 
359 	return (ifc);
360 }
361 
362 static int
363 if_clone_attach(struct if_clone *ifc)
364 {
365 	struct if_clone *ifc1;
366 
367 	IF_CLONERS_LOCK();
368 	LIST_FOREACH(ifc1, &V_if_cloners, ifc_list)
369 		if (strcmp(ifc->ifc_name, ifc1->ifc_name) == 0) {
370 			IF_CLONERS_UNLOCK();
371 			IF_CLONE_REMREF(ifc);
372 			return (EEXIST);
373 		}
374 	LIST_INSERT_HEAD(&V_if_cloners, ifc, ifc_list);
375 	V_if_cloners_count++;
376 	IF_CLONERS_UNLOCK();
377 
378 	return (0);
379 }
380 
381 struct if_clone *
382 if_clone_advanced(const char *name, u_int maxunit, ifc_match_t match,
383 	ifc_create_t create, ifc_destroy_t destroy)
384 {
385 	struct if_clone *ifc;
386 
387 	ifc = if_clone_alloc(name, maxunit);
388 	ifc->ifc_type = ADVANCED;
389 	ifc->ifc_match = match;
390 	ifc->ifc_create = create;
391 	ifc->ifc_destroy = destroy;
392 
393 	if (if_clone_attach(ifc) != 0)
394 		return (NULL);
395 
396 	EVENTHANDLER_INVOKE(if_clone_event, ifc);
397 
398 	return (ifc);
399 }
400 
401 struct if_clone *
402 if_clone_simple(const char *name, ifcs_create_t create, ifcs_destroy_t destroy,
403 	u_int minifs)
404 {
405 	struct if_clone *ifc;
406 	u_int unit;
407 
408 	ifc = if_clone_alloc(name, 0);
409 	ifc->ifc_type = SIMPLE;
410 	ifc->ifcs_create = create;
411 	ifc->ifcs_destroy = destroy;
412 	ifc->ifcs_minifs = minifs;
413 
414 	if (if_clone_attach(ifc) != 0)
415 		return (NULL);
416 
417 	for (unit = 0; unit < minifs; unit++) {
418 		char name[IFNAMSIZ];
419 		int error __unused;
420 
421 		snprintf(name, IFNAMSIZ, "%s%d", ifc->ifc_name, unit);
422 		error = if_clone_createif(ifc, name, IFNAMSIZ, NULL);
423 		KASSERT(error == 0,
424 		    ("%s: failed to create required interface %s",
425 		    __func__, name));
426 	}
427 
428 	EVENTHANDLER_INVOKE(if_clone_event, ifc);
429 
430 	return (ifc);
431 }
432 
433 /*
434  * Unregister a network interface cloner.
435  */
436 void
437 if_clone_detach(struct if_clone *ifc)
438 {
439 
440 	IF_CLONERS_LOCK();
441 	LIST_REMOVE(ifc, ifc_list);
442 	V_if_cloners_count--;
443 	IF_CLONERS_UNLOCK();
444 
445 	/* Allow all simples to be destroyed */
446 	if (ifc->ifc_type == SIMPLE)
447 		ifc->ifcs_minifs = 0;
448 
449 	/* destroy all interfaces for this cloner */
450 	while (!LIST_EMPTY(&ifc->ifc_iflist))
451 		if_clone_destroyif(ifc, LIST_FIRST(&ifc->ifc_iflist));
452 
453 	IF_CLONE_REMREF(ifc);
454 }
455 
456 static void
457 if_clone_free(struct if_clone *ifc)
458 {
459 
460 	KASSERT(LIST_EMPTY(&ifc->ifc_iflist),
461 	    ("%s: ifc_iflist not empty", __func__));
462 
463 	IF_CLONE_LOCK_DESTROY(ifc);
464 	delete_unrhdr(ifc->ifc_unrhdr);
465 	free(ifc, M_CLONE);
466 }
467 
468 /*
469  * Provide list of interface cloners to userspace.
470  */
471 int
472 if_clone_list(struct if_clonereq *ifcr)
473 {
474 	char *buf, *dst, *outbuf = NULL;
475 	struct if_clone *ifc;
476 	int buf_count, count, err = 0;
477 
478 	if (ifcr->ifcr_count < 0)
479 		return (EINVAL);
480 
481 	IF_CLONERS_LOCK();
482 	/*
483 	 * Set our internal output buffer size.  We could end up not
484 	 * reporting a cloner that is added between the unlock and lock
485 	 * below, but that's not a major problem.  Not caping our
486 	 * allocation to the number of cloners actually in the system
487 	 * could be because that would let arbitrary users cause us to
488 	 * allocate arbitrary amounts of kernel memory.
489 	 */
490 	buf_count = (V_if_cloners_count < ifcr->ifcr_count) ?
491 	    V_if_cloners_count : ifcr->ifcr_count;
492 	IF_CLONERS_UNLOCK();
493 
494 	outbuf = malloc(IFNAMSIZ*buf_count, M_CLONE, M_WAITOK | M_ZERO);
495 
496 	IF_CLONERS_LOCK();
497 
498 	ifcr->ifcr_total = V_if_cloners_count;
499 	if ((dst = ifcr->ifcr_buffer) == NULL) {
500 		/* Just asking how many there are. */
501 		goto done;
502 	}
503 	count = (V_if_cloners_count < buf_count) ?
504 	    V_if_cloners_count : buf_count;
505 
506 	for (ifc = LIST_FIRST(&V_if_cloners), buf = outbuf;
507 	    ifc != NULL && count != 0;
508 	    ifc = LIST_NEXT(ifc, ifc_list), count--, buf += IFNAMSIZ) {
509 		strlcpy(buf, ifc->ifc_name, IFNAMSIZ);
510 	}
511 
512 done:
513 	IF_CLONERS_UNLOCK();
514 	if (err == 0 && dst != NULL)
515 		err = copyout(outbuf, dst, buf_count*IFNAMSIZ);
516 	if (outbuf != NULL)
517 		free(outbuf, M_CLONE);
518 	return (err);
519 }
520 
521 /*
522  * if_clone_findifc() looks up ifnet from the current
523  * cloner list, and returns ifc if found.  Note that ifc_refcnt
524  * is incremented.
525  */
526 struct if_clone *
527 if_clone_findifc(struct ifnet *ifp)
528 {
529 	struct if_clone *ifc, *ifc0;
530 	struct ifnet *ifcifp;
531 
532 	ifc0 = NULL;
533 	IF_CLONERS_LOCK();
534 	LIST_FOREACH(ifc, &V_if_cloners, ifc_list) {
535 		IF_CLONE_LOCK(ifc);
536 		LIST_FOREACH(ifcifp, &ifc->ifc_iflist, if_clones) {
537 			if (ifp == ifcifp) {
538 				ifc0 = ifc;
539 				IF_CLONE_ADDREF_LOCKED(ifc);
540 				break;
541 			}
542 		}
543 		IF_CLONE_UNLOCK(ifc);
544 		if (ifc0 != NULL)
545 			break;
546 	}
547 	IF_CLONERS_UNLOCK();
548 
549 	return (ifc0);
550 }
551 
552 /*
553  * if_clone_addgroup() decrements ifc_refcnt because it is called after
554  * if_clone_findifc().
555  */
556 void
557 if_clone_addgroup(struct ifnet *ifp, struct if_clone *ifc)
558 {
559 	if ((ifc->ifc_flags & IFC_NOGROUP) == 0) {
560 		if_addgroup(ifp, ifc->ifc_name);
561 		IF_CLONE_REMREF(ifc);
562 	}
563 }
564 
565 /*
566  * A utility function to extract unit numbers from interface names of
567  * the form name###.
568  *
569  * Returns 0 on success and an error on failure.
570  */
571 int
572 ifc_name2unit(const char *name, int *unit)
573 {
574 	const char	*cp;
575 	int		cutoff = INT_MAX / 10;
576 	int		cutlim = INT_MAX % 10;
577 
578 	for (cp = name; *cp != '\0' && (*cp < '0' || *cp > '9'); cp++);
579 	if (*cp == '\0') {
580 		*unit = -1;
581 	} else if (cp[0] == '0' && cp[1] != '\0') {
582 		/* Disallow leading zeroes. */
583 		return (EINVAL);
584 	} else {
585 		for (*unit = 0; *cp != '\0'; cp++) {
586 			if (*cp < '0' || *cp > '9') {
587 				/* Bogus unit number. */
588 				return (EINVAL);
589 			}
590 			if (*unit > cutoff ||
591 			    (*unit == cutoff && *cp - '0' > cutlim))
592 				return (EINVAL);
593 			*unit = (*unit * 10) + (*cp - '0');
594 		}
595 	}
596 
597 	return (0);
598 }
599 
600 static int
601 ifc_alloc_unit_specific(struct if_clone *ifc, int *unit)
602 {
603 	char name[IFNAMSIZ];
604 
605 	if (*unit > ifc->ifc_maxunit)
606 		return (ENOSPC);
607 
608 	if (alloc_unr_specific(ifc->ifc_unrhdr, *unit) == -1)
609 		return (EEXIST);
610 
611 	snprintf(name, IFNAMSIZ, "%s%d", ifc->ifc_name, *unit);
612 	if (ifunit(name) != NULL) {
613 		free_unr(ifc->ifc_unrhdr, *unit);
614 		return (EEXIST);
615 	}
616 
617 	IF_CLONE_ADDREF(ifc);
618 
619 	return (0);
620 }
621 
622 static int
623 ifc_alloc_unit_next(struct if_clone *ifc, int *unit)
624 {
625 	int error;
626 
627 	*unit = alloc_unr(ifc->ifc_unrhdr);
628 	if (*unit == -1)
629 		return (ENOSPC);
630 
631 	free_unr(ifc->ifc_unrhdr, *unit);
632 	for (;;) {
633 		error = ifc_alloc_unit_specific(ifc, unit);
634 		if (error != EEXIST)
635 			break;
636 
637 		(*unit)++;
638 	}
639 
640 	return (error);
641 }
642 
643 int
644 ifc_alloc_unit(struct if_clone *ifc, int *unit)
645 {
646 	if (*unit < 0)
647 		return (ifc_alloc_unit_next(ifc, unit));
648 	else
649 		return (ifc_alloc_unit_specific(ifc, unit));
650 }
651 
652 void
653 ifc_free_unit(struct if_clone *ifc, int unit)
654 {
655 
656 	free_unr(ifc->ifc_unrhdr, unit);
657 	IF_CLONE_REMREF(ifc);
658 }
659 
660 static int
661 ifc_simple_match(struct if_clone *ifc, const char *name)
662 {
663 	const char *cp;
664 	int i;
665 
666 	/* Match the name */
667 	for (cp = name, i = 0; i < strlen(ifc->ifc_name); i++, cp++) {
668 		if (ifc->ifc_name[i] != *cp)
669 			return (0);
670 	}
671 
672 	/* Make sure there's a unit number or nothing after the name */
673 	for (; *cp != '\0'; cp++) {
674 		if (*cp < '0' || *cp > '9')
675 			return (0);
676 	}
677 
678 	return (1);
679 }
680 
681 static int
682 ifc_simple_create(struct if_clone *ifc, char *name, size_t len, caddr_t params)
683 {
684 	char *dp;
685 	int wildcard;
686 	int unit;
687 	int err;
688 
689 	err = ifc_name2unit(name, &unit);
690 	if (err != 0)
691 		return (err);
692 
693 	wildcard = (unit < 0);
694 
695 	err = ifc_alloc_unit(ifc, &unit);
696 	if (err != 0)
697 		return (err);
698 
699 	err = ifc->ifcs_create(ifc, unit, params);
700 	if (err != 0) {
701 		ifc_free_unit(ifc, unit);
702 		return (err);
703 	}
704 
705 	/* In the wildcard case, we need to update the name. */
706 	if (wildcard) {
707 		for (dp = name; *dp != '\0'; dp++);
708 		if (snprintf(dp, len - (dp-name), "%d", unit) >
709 		    len - (dp-name) - 1) {
710 			/*
711 			 * This can only be a programmer error and
712 			 * there's no straightforward way to recover if
713 			 * it happens.
714 			 */
715 			panic("if_clone_create(): interface name too long");
716 		}
717 
718 	}
719 
720 	return (0);
721 }
722 
723 static int
724 ifc_simple_destroy(struct if_clone *ifc, struct ifnet *ifp)
725 {
726 	int unit;
727 
728 	unit = ifp->if_dunit;
729 
730 	if (unit < ifc->ifcs_minifs)
731 		return (EINVAL);
732 
733 	ifc->ifcs_destroy(ifp);
734 
735 	ifc_free_unit(ifc, unit);
736 
737 	return (0);
738 }
739 
740 const char *
741 ifc_name(struct if_clone *ifc)
742 {
743 	return (ifc->ifc_name);
744 }
745 
746 void
747 ifc_flags_set(struct if_clone *ifc, int flags)
748 {
749 	ifc->ifc_flags = flags;
750 }
751 
752 int
753 ifc_flags_get(struct if_clone *ifc)
754 {
755 	return (ifc->ifc_flags);
756 }
757