xref: /freebsd/sys/net/if_clone.c (revision 3c4ba5f55438f7afd4f4b0b56f88f2bb505fd6a6)
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_private.h>
50 #include <net/if_clone.h>
51 #include <net/radix.h>
52 #include <net/route.h>
53 #include <net/vnet.h>
54 
55 /* Current IF_MAXUNIT expands maximum to 5 characters. */
56 #define	IFCLOSIZ	(IFNAMSIZ - 5)
57 
58 /*
59  * Structure describing a `cloning' interface.
60  *
61  * List of locks
62  * (c)		const until freeing
63  * (d)		driver specific data, may need external protection.
64  * (e)		locked by if_cloners_mtx
65  * (i)		locked by ifc_mtx mtx
66  */
67 struct if_clone {
68 	char ifc_name[IFCLOSIZ];	/* (c) Name of device, e.g. `gif' */
69 	struct unrhdr *ifc_unrhdr;	/* (c) alloc_unr(9) header */
70 	int ifc_maxunit;		/* (c) maximum unit number */
71 	int ifc_flags;
72 	long ifc_refcnt;		/* (i) Reference count. */
73 	LIST_HEAD(, ifnet) ifc_iflist;	/* (i) List of cloned interfaces */
74 	struct mtx ifc_mtx;		/* Mutex to protect members. */
75 
76 	ifc_match_f *ifc_match;		/* (c) Matcher function */
77 	ifc_create_f *ifc_create;	/* (c) Creates new interface */
78 	ifc_destroy_f *ifc_destroy;	/* (c) Destroys cloned interface */
79 
80 #ifdef CLONE_COMPAT_13
81 	/* (c) Driver specific cloning functions.  Called with no locks held. */
82 	union {
83 		struct {	/* advanced cloner */
84 			ifc_create_t	*_ifc_create;
85 			ifc_destroy_t	*_ifc_destroy;
86 		} A;
87 		struct {	/* simple cloner */
88 			ifcs_create_t	*_ifcs_create;
89 			ifcs_destroy_t	*_ifcs_destroy;
90 			int		_ifcs_minifs;	/* minimum ifs */
91 
92 		} S;
93 	} U;
94 #define	ifca_create	U.A._ifc_create
95 #define	ifca_destroy	U.A._ifc_destroy
96 #define	ifcs_create	U.S._ifcs_create
97 #define	ifcs_destroy	U.S._ifcs_destroy
98 #define	ifcs_minifs	U.S._ifcs_minifs
99 #endif
100 
101 	LIST_ENTRY(if_clone) ifc_list;	/* (e) On list of cloners */
102 };
103 
104 
105 
106 static void	if_clone_free(struct if_clone *ifc);
107 static int	if_clone_createif(struct if_clone *ifc, char *name, size_t len,
108 		    struct ifc_data *ifd, struct ifnet **ifpp);
109 
110 static int ifc_simple_match(struct if_clone *ifc, const char *name);
111 static int ifc_handle_unit(struct if_clone *ifc, char *name, size_t len, int *punit);
112 static struct if_clone *ifc_find_cloner(const char *name);
113 static struct if_clone *ifc_find_cloner_match(const char *name);
114 
115 #ifdef CLONE_COMPAT_13
116 static int ifc_simple_create_wrapper(struct if_clone *ifc, char *name, size_t maxlen,
117     struct ifc_data *ifc_data, struct ifnet **ifpp);
118 static int ifc_advanced_create_wrapper(struct if_clone *ifc, char *name, size_t maxlen,
119     struct ifc_data *ifc_data, struct ifnet **ifpp);
120 #endif
121 
122 static struct mtx if_cloners_mtx;
123 MTX_SYSINIT(if_cloners_lock, &if_cloners_mtx, "if_cloners lock", MTX_DEF);
124 VNET_DEFINE_STATIC(int, if_cloners_count);
125 VNET_DEFINE(LIST_HEAD(, if_clone), if_cloners);
126 
127 #define	V_if_cloners_count	VNET(if_cloners_count)
128 #define	V_if_cloners		VNET(if_cloners)
129 
130 #define IF_CLONERS_LOCK_ASSERT()	mtx_assert(&if_cloners_mtx, MA_OWNED)
131 #define IF_CLONERS_LOCK()		mtx_lock(&if_cloners_mtx)
132 #define IF_CLONERS_UNLOCK()		mtx_unlock(&if_cloners_mtx)
133 
134 #define IF_CLONE_LOCK_INIT(ifc)		\
135     mtx_init(&(ifc)->ifc_mtx, "if_clone lock", NULL, MTX_DEF)
136 #define IF_CLONE_LOCK_DESTROY(ifc)	mtx_destroy(&(ifc)->ifc_mtx)
137 #define IF_CLONE_LOCK_ASSERT(ifc)	mtx_assert(&(ifc)->ifc_mtx, MA_OWNED)
138 #define IF_CLONE_LOCK(ifc)		mtx_lock(&(ifc)->ifc_mtx)
139 #define IF_CLONE_UNLOCK(ifc)		mtx_unlock(&(ifc)->ifc_mtx)
140 
141 #define IF_CLONE_ADDREF(ifc)						\
142 	do {								\
143 		IF_CLONE_LOCK(ifc);					\
144 		IF_CLONE_ADDREF_LOCKED(ifc);				\
145 		IF_CLONE_UNLOCK(ifc);					\
146 	} while (0)
147 #define IF_CLONE_ADDREF_LOCKED(ifc)					\
148 	do {								\
149 		IF_CLONE_LOCK_ASSERT(ifc);				\
150 		KASSERT((ifc)->ifc_refcnt >= 0,				\
151 		    ("negative refcnt %ld", (ifc)->ifc_refcnt));	\
152 		(ifc)->ifc_refcnt++;					\
153 	} while (0)
154 #define IF_CLONE_REMREF(ifc)						\
155 	do {								\
156 		IF_CLONE_LOCK(ifc);					\
157 		IF_CLONE_REMREF_LOCKED(ifc);				\
158 	} while (0)
159 #define IF_CLONE_REMREF_LOCKED(ifc)					\
160 	do {								\
161 		IF_CLONE_LOCK_ASSERT(ifc);				\
162 		KASSERT((ifc)->ifc_refcnt > 0,				\
163 		    ("bogus refcnt %ld", (ifc)->ifc_refcnt));		\
164 		if (--(ifc)->ifc_refcnt == 0) {				\
165 			IF_CLONE_UNLOCK(ifc);				\
166 			if_clone_free(ifc);				\
167 		} else {						\
168 			/* silently free the lock */			\
169 			IF_CLONE_UNLOCK(ifc);				\
170 		}							\
171 	} while (0)
172 
173 #define IFC_IFLIST_INSERT(_ifc, _ifp)					\
174 	LIST_INSERT_HEAD(&_ifc->ifc_iflist, _ifp, if_clones)
175 #define IFC_IFLIST_REMOVE(_ifc, _ifp)					\
176 	LIST_REMOVE(_ifp, if_clones)
177 
178 static MALLOC_DEFINE(M_CLONE, "clone", "interface cloning framework");
179 
180 void
181 vnet_if_clone_init(void)
182 {
183 
184 	LIST_INIT(&V_if_cloners);
185 }
186 
187 /*
188  * Lookup and create a clone network interface.
189  */
190 int
191 ifc_create_ifp(const char *name, struct ifc_data *ifd,
192     struct ifnet **ifpp)
193 {
194 	struct if_clone *ifc;
195 	char ifname[IFNAMSIZ];
196 	struct ifnet *ifp = NULL;
197 	int error;
198 
199 	/* Try to find an applicable cloner for this request */
200 	ifc = ifc_find_cloner_match(name);
201 	if (ifc == NULL)
202 		return (EINVAL);
203 
204 	strlcpy(ifname, name, IFNAMSIZ);
205 	error = if_clone_createif(ifc, ifname, IFNAMSIZ, ifd, &ifp);
206 	if (ifpp != NULL)
207 		*ifpp = ifp;
208 
209 	return (error);
210 }
211 
212 int
213 if_clone_create(char *name, size_t len, caddr_t params)
214 {
215 	struct ifc_data ifd = { .params = params };
216 	struct ifnet *ifp;
217 
218 	int error = ifc_create_ifp(name, &ifd, &ifp);
219 
220 	if (error == 0)
221 		strlcpy(name, if_name(ifp), len);
222 
223 	return (error);
224 }
225 
226 void
227 ifc_link_ifp(struct if_clone *ifc, struct ifnet *ifp)
228 {
229 
230 	if ((ifc->ifc_flags & IFC_NOGROUP) == 0)
231 		if_addgroup(ifp, ifc->ifc_name);
232 
233 	IF_CLONE_LOCK(ifc);
234 	IFC_IFLIST_INSERT(ifc, ifp);
235 	IF_CLONE_UNLOCK(ifc);
236 }
237 
238 void
239 if_clone_addif(struct if_clone *ifc, struct ifnet *ifp)
240 {
241 	ifc_link_ifp(ifc, ifp);
242 }
243 
244 bool
245 ifc_unlink_ifp(struct if_clone *ifc, struct ifnet *ifp)
246 {
247 	struct ifnet *ifcifp;
248 
249 	IF_CLONE_LOCK(ifc);
250 	LIST_FOREACH(ifcifp, &ifc->ifc_iflist, if_clones) {
251 		if (ifcifp == ifp) {
252 			IFC_IFLIST_REMOVE(ifc, ifp);
253 			break;
254 		}
255 	}
256 	IF_CLONE_UNLOCK(ifc);
257 
258 	if (ifcifp != NULL && (ifc->ifc_flags & IFC_F_NOGROUP) == 0)
259 		if_delgroup(ifp, ifc->ifc_name);
260 
261 	return (ifcifp != NULL);
262 }
263 
264 static struct if_clone *
265 ifc_find_cloner_match(const char *name)
266 {
267 	struct if_clone *ifc;
268 
269 	IF_CLONERS_LOCK();
270 	LIST_FOREACH(ifc, &V_if_cloners, ifc_list) {
271 		if (ifc->ifc_match(ifc, name))
272 			break;
273 	}
274 	IF_CLONERS_UNLOCK();
275 
276 	return (ifc);
277 }
278 
279 static struct if_clone *
280 ifc_find_cloner(const char *name)
281 {
282 	struct if_clone *ifc;
283 
284 	IF_CLONERS_LOCK();
285 	LIST_FOREACH(ifc, &V_if_cloners, ifc_list) {
286 		if (strcmp(ifc->ifc_name, name) == 0) {
287 			break;
288 		}
289 	}
290 	IF_CLONERS_UNLOCK();
291 
292 	return (ifc);
293 }
294 
295 static struct if_clone *
296 ifc_find_cloner_in_vnet(const char *name, struct vnet *vnet)
297 {
298 	CURVNET_SET_QUIET(vnet);
299 	struct if_clone *ifc = ifc_find_cloner(name);
300 	CURVNET_RESTORE();
301 
302 	return (ifc);
303 }
304 
305 /*
306  * Create a clone network interface.
307  */
308 static int
309 if_clone_createif(struct if_clone *ifc, char *name, size_t len,
310     struct ifc_data *ifd, struct ifnet **ifpp)
311 {
312 	int err, unit = 0;
313 
314 	if (ifunit(name) != NULL)
315 		return (EEXIST);
316 
317 	if (ifc->ifc_flags & IFC_F_AUTOUNIT) {
318 		if ((err = ifc_handle_unit(ifc, name, len, &unit)) != 0)
319 			return (err);
320 		ifd->unit = unit;
321 	}
322 	*ifpp = NULL;
323 	err = (*ifc->ifc_create)(ifc, name, len, ifd, ifpp);
324 
325 	if (err == 0) {
326 		MPASS(*ifpp != NULL);
327 		if_clone_addif(ifc, *ifpp);
328 	} else if (ifc->ifc_flags & IFC_F_AUTOUNIT)
329 		ifc_free_unit(ifc, unit);
330 
331 	return (err);
332 }
333 
334 /*
335  * Lookup and destroy a clone network interface.
336  */
337 int
338 if_clone_destroy(const char *name)
339 {
340 	int err;
341 	struct if_clone *ifc;
342 	struct ifnet *ifp;
343 
344 	ifp = ifunit_ref(name);
345 	if (ifp == NULL)
346 		return (ENXIO);
347 
348 	ifc = ifc_find_cloner_in_vnet(ifp->if_dname, ifp->if_home_vnet);
349 	if (ifc == NULL) {
350 		if_rele(ifp);
351 		return (EINVAL);
352 	}
353 
354 	err = if_clone_destroyif(ifc, ifp);
355 	if_rele(ifp);
356 	return err;
357 }
358 
359 /*
360  * Destroy a clone network interface.
361  */
362 static int
363 if_clone_destroyif_flags(struct if_clone *ifc, struct ifnet *ifp, uint32_t flags)
364 {
365 	int err;
366 
367 	/*
368 	 * Given that the cloned ifnet might be attached to a different
369 	 * vnet from where its cloner was registered, we have to
370 	 * switch to the vnet context of the target vnet.
371 	 */
372 	CURVNET_SET_QUIET(ifp->if_vnet);
373 
374 	if (!ifc_unlink_ifp(ifc, ifp)) {
375 		CURVNET_RESTORE();
376 		return (ENXIO);		/* ifp is not on the list. */
377 	}
378 
379 	int unit = ifp->if_dunit;
380 	err = (*ifc->ifc_destroy)(ifc, ifp, flags);
381 
382 	if (err != 0)
383 		ifc_link_ifp(ifc, ifp);
384 	else if (ifc->ifc_flags & IFC_F_AUTOUNIT)
385 		ifc_free_unit(ifc, unit);
386 	CURVNET_RESTORE();
387 	return (err);
388 }
389 
390 int
391 if_clone_destroyif(struct if_clone *ifc, struct ifnet *ifp)
392 {
393 	return (if_clone_destroyif_flags(ifc, ifp, 0));
394 }
395 
396 static struct if_clone *
397 if_clone_alloc(const char *name, int maxunit)
398 {
399 	struct if_clone *ifc;
400 
401 	KASSERT(name != NULL, ("%s: no name\n", __func__));
402 
403 	ifc = malloc(sizeof(struct if_clone), M_CLONE, M_WAITOK | M_ZERO);
404 	strncpy(ifc->ifc_name, name, IFCLOSIZ-1);
405 	IF_CLONE_LOCK_INIT(ifc);
406 	IF_CLONE_ADDREF(ifc);
407 	ifc->ifc_maxunit = maxunit ? maxunit : IF_MAXUNIT;
408 	ifc->ifc_unrhdr = new_unrhdr(0, ifc->ifc_maxunit, &ifc->ifc_mtx);
409 	LIST_INIT(&ifc->ifc_iflist);
410 
411 	return (ifc);
412 }
413 
414 static int
415 if_clone_attach(struct if_clone *ifc)
416 {
417 	struct if_clone *ifc1;
418 
419 	IF_CLONERS_LOCK();
420 	LIST_FOREACH(ifc1, &V_if_cloners, ifc_list)
421 		if (strcmp(ifc->ifc_name, ifc1->ifc_name) == 0) {
422 			IF_CLONERS_UNLOCK();
423 			IF_CLONE_REMREF(ifc);
424 			return (EEXIST);
425 		}
426 	LIST_INSERT_HEAD(&V_if_cloners, ifc, ifc_list);
427 	V_if_cloners_count++;
428 	IF_CLONERS_UNLOCK();
429 
430 	return (0);
431 }
432 
433 struct if_clone *
434 ifc_attach_cloner(const char *name, struct if_clone_addreq *req)
435 {
436 	if (req->create_f == NULL || req->destroy_f == NULL)
437 		return (NULL);
438 	if (strnlen(name, IFCLOSIZ) >= (IFCLOSIZ - 1))
439 		return (NULL);
440 
441 	struct if_clone *ifc = if_clone_alloc(name, req->maxunit);
442 	ifc->ifc_match = req->match_f != NULL ? req->match_f : ifc_simple_match;
443 	ifc->ifc_create = req->create_f;
444 	ifc->ifc_destroy = req->destroy_f;
445 	ifc->ifc_flags = (req->flags & (IFC_F_AUTOUNIT | IFC_F_NOGROUP));
446 
447 	if (if_clone_attach(ifc) != 0)
448 		return (NULL);
449 
450 	EVENTHANDLER_INVOKE(if_clone_event, ifc);
451 
452 	return (ifc);
453 }
454 
455 void
456 ifc_detach_cloner(struct if_clone *ifc)
457 {
458 	if_clone_detach(ifc);
459 }
460 
461 
462 #ifdef CLONE_COMPAT_13
463 
464 static int
465 ifc_advanced_create_wrapper(struct if_clone *ifc, char *name, size_t maxlen,
466     struct ifc_data *ifc_data, struct ifnet **ifpp)
467 {
468 	int error = ifc->ifca_create(ifc, name, maxlen, ifc_data->params);
469 
470 	if (error == 0)
471 		*ifpp = ifunit(name);
472 	return (error);
473 }
474 
475 static int
476 ifc_advanced_destroy_wrapper(struct if_clone *ifc, struct ifnet *ifp, uint32_t flags)
477 {
478 	if (ifc->ifca_destroy == NULL)
479 		return (ENOTSUP);
480 	return (ifc->ifca_destroy(ifc, ifp));
481 }
482 
483 struct if_clone *
484 if_clone_advanced(const char *name, u_int maxunit, ifc_match_t match,
485 	ifc_create_t create, ifc_destroy_t destroy)
486 {
487 	struct if_clone *ifc;
488 
489 	ifc = if_clone_alloc(name, maxunit);
490 	ifc->ifc_match = match;
491 	ifc->ifc_create = ifc_advanced_create_wrapper;
492 	ifc->ifc_destroy = ifc_advanced_destroy_wrapper;
493 	ifc->ifca_destroy = destroy;
494 	ifc->ifca_create = create;
495 
496 	if (if_clone_attach(ifc) != 0)
497 		return (NULL);
498 
499 	EVENTHANDLER_INVOKE(if_clone_event, ifc);
500 
501 	return (ifc);
502 }
503 
504 static int
505 ifc_simple_create_wrapper(struct if_clone *ifc, char *name, size_t maxlen,
506     struct ifc_data *ifc_data, struct ifnet **ifpp)
507 {
508 	int unit = 0;
509 
510 	ifc_name2unit(name, &unit);
511 	int error = ifc->ifcs_create(ifc, unit, ifc_data->params);
512 	if (error == 0)
513 		*ifpp = ifunit(name);
514 	return (error);
515 }
516 
517 static int
518 ifc_simple_destroy_wrapper(struct if_clone *ifc, struct ifnet *ifp, uint32_t flags)
519 {
520 	if (ifp->if_dunit < ifc->ifcs_minifs && (flags & IFC_F_FORCE) == 0)
521 		return (EINVAL);
522 
523 	ifc->ifcs_destroy(ifp);
524 	return (0);
525 }
526 
527 struct if_clone *
528 if_clone_simple(const char *name, ifcs_create_t create, ifcs_destroy_t destroy,
529 	u_int minifs)
530 {
531 	struct if_clone *ifc;
532 	u_int unit;
533 
534 	ifc = if_clone_alloc(name, 0);
535 	ifc->ifc_match = ifc_simple_match;
536 	ifc->ifc_create = ifc_simple_create_wrapper;
537 	ifc->ifc_destroy = ifc_simple_destroy_wrapper;
538 	ifc->ifcs_create = create;
539 	ifc->ifcs_destroy = destroy;
540 	ifc->ifcs_minifs = minifs;
541 	ifc->ifc_flags = IFC_F_AUTOUNIT;
542 
543 	if (if_clone_attach(ifc) != 0)
544 		return (NULL);
545 
546 	for (unit = 0; unit < minifs; unit++) {
547 		char name[IFNAMSIZ];
548 		int error __unused;
549 		struct ifc_data ifd = {};
550 		struct ifnet *ifp;
551 
552 		snprintf(name, IFNAMSIZ, "%s%d", ifc->ifc_name, unit);
553 		error = if_clone_createif(ifc, name, IFNAMSIZ, &ifd, &ifp);
554 		KASSERT(error == 0,
555 		    ("%s: failed to create required interface %s",
556 		    __func__, name));
557 	}
558 
559 	EVENTHANDLER_INVOKE(if_clone_event, ifc);
560 
561 	return (ifc);
562 }
563 #endif
564 
565 /*
566  * Unregister a network interface cloner.
567  */
568 void
569 if_clone_detach(struct if_clone *ifc)
570 {
571 
572 	IF_CLONERS_LOCK();
573 	LIST_REMOVE(ifc, ifc_list);
574 	V_if_cloners_count--;
575 	IF_CLONERS_UNLOCK();
576 
577 	/* destroy all interfaces for this cloner */
578 	while (!LIST_EMPTY(&ifc->ifc_iflist))
579 		if_clone_destroyif_flags(ifc, LIST_FIRST(&ifc->ifc_iflist), IFC_F_FORCE);
580 
581 	IF_CLONE_REMREF(ifc);
582 }
583 
584 static void
585 if_clone_free(struct if_clone *ifc)
586 {
587 
588 	KASSERT(LIST_EMPTY(&ifc->ifc_iflist),
589 	    ("%s: ifc_iflist not empty", __func__));
590 
591 	IF_CLONE_LOCK_DESTROY(ifc);
592 	delete_unrhdr(ifc->ifc_unrhdr);
593 	free(ifc, M_CLONE);
594 }
595 
596 /*
597  * Provide list of interface cloners to userspace.
598  */
599 int
600 if_clone_list(struct if_clonereq *ifcr)
601 {
602 	char *buf, *dst, *outbuf = NULL;
603 	struct if_clone *ifc;
604 	int buf_count, count, err = 0;
605 
606 	if (ifcr->ifcr_count < 0)
607 		return (EINVAL);
608 
609 	IF_CLONERS_LOCK();
610 	/*
611 	 * Set our internal output buffer size.  We could end up not
612 	 * reporting a cloner that is added between the unlock and lock
613 	 * below, but that's not a major problem.  Not caping our
614 	 * allocation to the number of cloners actually in the system
615 	 * could be because that would let arbitrary users cause us to
616 	 * allocate arbitrary amounts of kernel memory.
617 	 */
618 	buf_count = (V_if_cloners_count < ifcr->ifcr_count) ?
619 	    V_if_cloners_count : ifcr->ifcr_count;
620 	IF_CLONERS_UNLOCK();
621 
622 	outbuf = malloc(IFNAMSIZ*buf_count, M_CLONE, M_WAITOK | M_ZERO);
623 
624 	IF_CLONERS_LOCK();
625 
626 	ifcr->ifcr_total = V_if_cloners_count;
627 	if ((dst = ifcr->ifcr_buffer) == NULL) {
628 		/* Just asking how many there are. */
629 		goto done;
630 	}
631 	count = (V_if_cloners_count < buf_count) ?
632 	    V_if_cloners_count : buf_count;
633 
634 	for (ifc = LIST_FIRST(&V_if_cloners), buf = outbuf;
635 	    ifc != NULL && count != 0;
636 	    ifc = LIST_NEXT(ifc, ifc_list), count--, buf += IFNAMSIZ) {
637 		strlcpy(buf, ifc->ifc_name, IFNAMSIZ);
638 	}
639 
640 done:
641 	IF_CLONERS_UNLOCK();
642 	if (err == 0 && dst != NULL)
643 		err = copyout(outbuf, dst, buf_count*IFNAMSIZ);
644 	if (outbuf != NULL)
645 		free(outbuf, M_CLONE);
646 	return (err);
647 }
648 
649 #ifdef VIMAGE
650 /*
651  * if_clone_restoregroup() is used in context of if_vmove().
652  *
653  * Since if_detach_internal() has removed the interface from ALL groups, we
654  * need to "restore" interface membership in the cloner's group.  Note that
655  * interface belongs to cloner in its home vnet, so we first find the original
656  * cloner, and then we confirm that cloner with the same name exists in the
657  * current vnet.
658  */
659 void
660 if_clone_restoregroup(struct ifnet *ifp)
661 {
662 	struct if_clone *ifc;
663 	struct ifnet *ifcifp;
664 	char ifc_name[IFCLOSIZ] = { [0] = '\0' };
665 
666 	CURVNET_SET_QUIET(ifp->if_home_vnet);
667 	IF_CLONERS_LOCK();
668 	LIST_FOREACH(ifc, &V_if_cloners, ifc_list) {
669 		IF_CLONE_LOCK(ifc);
670 		LIST_FOREACH(ifcifp, &ifc->ifc_iflist, if_clones) {
671 			if (ifp == ifcifp) {
672 				strncpy(ifc_name, ifc->ifc_name, IFCLOSIZ-1);
673 				break;
674 			}
675 		}
676 		IF_CLONE_UNLOCK(ifc);
677 		if (ifc_name[0] != '\0')
678 			break;
679 	}
680 	CURVNET_RESTORE();
681 	LIST_FOREACH(ifc, &V_if_cloners, ifc_list)
682 		if (strcmp(ifc->ifc_name, ifc_name) == 0 &&
683 		    ((ifc->ifc_flags & IFC_NOGROUP) == 0))
684 			break;
685 	IF_CLONERS_UNLOCK();
686 
687 	if (ifc != NULL)
688 		if_addgroup(ifp, ifc_name);
689 }
690 #endif
691 
692 /*
693  * A utility function to extract unit numbers from interface names of
694  * the form name###.
695  *
696  * Returns 0 on success and an error on failure.
697  */
698 int
699 ifc_name2unit(const char *name, int *unit)
700 {
701 	const char	*cp;
702 	int		cutoff = INT_MAX / 10;
703 	int		cutlim = INT_MAX % 10;
704 
705 	for (cp = name; *cp != '\0' && (*cp < '0' || *cp > '9'); cp++)
706 		;
707 	if (*cp == '\0') {
708 		*unit = -1;
709 	} else if (cp[0] == '0' && cp[1] != '\0') {
710 		/* Disallow leading zeroes. */
711 		return (EINVAL);
712 	} else {
713 		for (*unit = 0; *cp != '\0'; cp++) {
714 			if (*cp < '0' || *cp > '9') {
715 				/* Bogus unit number. */
716 				return (EINVAL);
717 			}
718 			if (*unit > cutoff ||
719 			    (*unit == cutoff && *cp - '0' > cutlim))
720 				return (EINVAL);
721 			*unit = (*unit * 10) + (*cp - '0');
722 		}
723 	}
724 
725 	return (0);
726 }
727 
728 static int
729 ifc_alloc_unit_specific(struct if_clone *ifc, int *unit)
730 {
731 	char name[IFNAMSIZ];
732 
733 	if (*unit > ifc->ifc_maxunit)
734 		return (ENOSPC);
735 
736 	if (alloc_unr_specific(ifc->ifc_unrhdr, *unit) == -1)
737 		return (EEXIST);
738 
739 	snprintf(name, IFNAMSIZ, "%s%d", ifc->ifc_name, *unit);
740 	if (ifunit(name) != NULL) {
741 		free_unr(ifc->ifc_unrhdr, *unit);
742 		return (EEXIST);
743 	}
744 
745 	IF_CLONE_ADDREF(ifc);
746 
747 	return (0);
748 }
749 
750 static int
751 ifc_alloc_unit_next(struct if_clone *ifc, int *unit)
752 {
753 	int error;
754 
755 	*unit = alloc_unr(ifc->ifc_unrhdr);
756 	if (*unit == -1)
757 		return (ENOSPC);
758 
759 	free_unr(ifc->ifc_unrhdr, *unit);
760 	for (;;) {
761 		error = ifc_alloc_unit_specific(ifc, unit);
762 		if (error != EEXIST)
763 			break;
764 
765 		(*unit)++;
766 	}
767 
768 	return (error);
769 }
770 
771 int
772 ifc_alloc_unit(struct if_clone *ifc, int *unit)
773 {
774 	if (*unit < 0)
775 		return (ifc_alloc_unit_next(ifc, unit));
776 	else
777 		return (ifc_alloc_unit_specific(ifc, unit));
778 }
779 
780 void
781 ifc_free_unit(struct if_clone *ifc, int unit)
782 {
783 
784 	free_unr(ifc->ifc_unrhdr, unit);
785 	IF_CLONE_REMREF(ifc);
786 }
787 
788 static int
789 ifc_simple_match(struct if_clone *ifc, const char *name)
790 {
791 	const char *cp;
792 	int i;
793 
794 	/* Match the name */
795 	for (cp = name, i = 0; i < strlen(ifc->ifc_name); i++, cp++) {
796 		if (ifc->ifc_name[i] != *cp)
797 			return (0);
798 	}
799 
800 	/* Make sure there's a unit number or nothing after the name */
801 	for (; *cp != '\0'; cp++) {
802 		if (*cp < '0' || *cp > '9')
803 			return (0);
804 	}
805 
806 	return (1);
807 }
808 
809 static int
810 ifc_handle_unit(struct if_clone *ifc, char *name, size_t len, int *punit)
811 {
812 	char *dp;
813 	int wildcard;
814 	int unit;
815 	int err;
816 
817 	err = ifc_name2unit(name, &unit);
818 	if (err != 0)
819 		return (err);
820 
821 	wildcard = (unit < 0);
822 
823 	err = ifc_alloc_unit(ifc, &unit);
824 	if (err != 0)
825 		return (err);
826 
827 	/* In the wildcard case, we need to update the name. */
828 	if (wildcard) {
829 		for (dp = name; *dp != '\0'; dp++);
830 		if (snprintf(dp, len - (dp-name), "%d", unit) >
831 		    len - (dp-name) - 1) {
832 			/*
833 			 * This can only be a programmer error and
834 			 * there's no straightforward way to recover if
835 			 * it happens.
836 			 */
837 			panic("if_clone_create(): interface name too long");
838 		}
839 	}
840 	*punit = unit;
841 
842 	return (0);
843 }
844 
845 int
846 ifc_copyin(const struct ifc_data *ifd, void *target, size_t len)
847 {
848 	if (ifd->params == NULL)
849 		return (EINVAL);
850 
851 	if (ifd->flags & IFC_F_SYSSPACE) {
852 		memcpy(target, ifd->params, len);
853 		return (0);
854 	} else
855 		return (copyin(ifd->params, target, len));
856 }
857 
858 const char *
859 ifc_name(struct if_clone *ifc)
860 {
861 	return (ifc->ifc_name);
862 }
863 
864 void
865 ifc_flags_set(struct if_clone *ifc, int flags)
866 {
867 	ifc->ifc_flags = flags;
868 }
869 
870 int
871 ifc_flags_get(struct if_clone *ifc)
872 {
873 	return (ifc->ifc_flags);
874 }
875