xref: /freebsd/sys/net/if_clone.c (revision 54ebdd631db8c0bba2baab0155f603a8b5cf014a) 
1 /*-
2  * Copyright (c) 1980, 1986, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	@(#)if.c	8.5 (Berkeley) 1/9/95
30  * $FreeBSD$
31  */
32 
33 #include <sys/param.h>
34 #include <sys/malloc.h>
35 #include <sys/limits.h>
36 #include <sys/lock.h>
37 #include <sys/mutex.h>
38 #include <sys/kernel.h>
39 #include <sys/systm.h>
40 #include <sys/types.h>
41 #include <sys/socket.h>
42 
43 #include <net/if.h>
44 #include <net/if_clone.h>
45 #if 0
46 #include <net/if_dl.h>
47 #endif
48 #include <net/if_types.h>
49 #include <net/if_var.h>
50 #include <net/radix.h>
51 #include <net/route.h>
52 
53 static void	if_clone_free(struct if_clone *ifc);
54 static int	if_clone_createif(struct if_clone *ifc, char *name, size_t len,
55 		    caddr_t params);
56 
57 static struct mtx	if_cloners_mtx;
58 static int		if_cloners_count;
59 LIST_HEAD(, if_clone)	if_cloners = LIST_HEAD_INITIALIZER(if_cloners);
60 
61 #define IF_CLONERS_LOCK_INIT()		\
62     mtx_init(&if_cloners_mtx, "if_cloners lock", NULL, MTX_DEF)
63 #define IF_CLONERS_LOCK_ASSERT()	mtx_assert(&if_cloners_mtx, MA_OWNED)
64 #define IF_CLONERS_LOCK()		mtx_lock(&if_cloners_mtx)
65 #define IF_CLONERS_UNLOCK()		mtx_unlock(&if_cloners_mtx)
66 
67 #define IF_CLONE_LOCK_INIT(ifc)		\
68     mtx_init(&(ifc)->ifc_mtx, "if_clone lock", NULL, MTX_DEF)
69 #define IF_CLONE_LOCK_DESTROY(ifc)	mtx_destroy(&(ifc)->ifc_mtx)
70 #define IF_CLONE_LOCK_ASSERT(ifc)	mtx_assert(&(ifc)->ifc_mtx, MA_OWNED)
71 #define IF_CLONE_LOCK(ifc)		mtx_lock(&(ifc)->ifc_mtx)
72 #define IF_CLONE_UNLOCK(ifc)		mtx_unlock(&(ifc)->ifc_mtx)
73 
74 #define IF_CLONE_ADDREF(ifc)						\
75 	do {								\
76 		IF_CLONE_LOCK(ifc);					\
77 		IF_CLONE_ADDREF_LOCKED(ifc);				\
78 		IF_CLONE_UNLOCK(ifc);					\
79 	} while (0)
80 #define IF_CLONE_ADDREF_LOCKED(ifc)					\
81 	do {								\
82 		IF_CLONE_LOCK_ASSERT(ifc);				\
83 		KASSERT((ifc)->ifc_refcnt >= 0,				\
84 		    ("negative refcnt %ld", (ifc)->ifc_refcnt));	\
85 		(ifc)->ifc_refcnt++;					\
86 	} while (0)
87 #define IF_CLONE_REMREF(ifc)						\
88 	do {								\
89 		IF_CLONE_LOCK(ifc);					\
90 		IF_CLONE_REMREF_LOCKED(ifc);				\
91 	} while (0)
92 #define IF_CLONE_REMREF_LOCKED(ifc)					\
93 	do {								\
94 		IF_CLONE_LOCK_ASSERT(ifc);				\
95 		KASSERT((ifc)->ifc_refcnt > 0,				\
96 		    ("bogus refcnt %ld", (ifc)->ifc_refcnt));		\
97 		if (--(ifc)->ifc_refcnt == 0) {				\
98 			IF_CLONE_UNLOCK(ifc);				\
99 			if_clone_free(ifc);				\
100 		} else {						\
101 			/* silently free the lock */			\
102 			IF_CLONE_UNLOCK(ifc);				\
103 		}							\
104 	} while (0)
105 
106 #define IFC_IFLIST_INSERT(_ifc, _ifp)					\
107 	LIST_INSERT_HEAD(&_ifc->ifc_iflist, _ifp, if_clones)
108 #define IFC_IFLIST_REMOVE(_ifc, _ifp)					\
109 	LIST_REMOVE(_ifp, if_clones)
110 
111 static MALLOC_DEFINE(M_CLONE, "clone", "interface cloning framework");
112 
113 void
114 if_clone_init(void)
115 {
116 	IF_CLONERS_LOCK_INIT();
117 }
118 
119 /*
120  * Lookup and create a clone network interface.
121  */
122 int
123 if_clone_create(char *name, size_t len, caddr_t params)
124 {
125 	struct if_clone *ifc;
126 
127 	/* Try to find an applicable cloner for this request */
128 	IF_CLONERS_LOCK();
129 	LIST_FOREACH(ifc, &if_cloners, ifc_list) {
130 		if (ifc->ifc_match(ifc, name)) {
131 			break;
132 		}
133 	}
134 	IF_CLONERS_UNLOCK();
135 
136 	if (ifc == NULL)
137 		return (EINVAL);
138 
139 	return (if_clone_createif(ifc, name, len, params));
140 }
141 
142 /*
143  * Create a clone network interface.
144  */
145 static int
146 if_clone_createif(struct if_clone *ifc, char *name, size_t len, caddr_t params)
147 {
148 	int err;
149 	struct ifnet *ifp;
150 
151 	if (ifunit(name) != NULL)
152 		return (EEXIST);
153 
154 	err = (*ifc->ifc_create)(ifc, name, len, params);
155 
156 	if (!err) {
157 		ifp = ifunit(name);
158 		if (ifp == NULL)
159 			panic("%s: lookup failed for %s", __func__, name);
160 
161 		if_addgroup(ifp, ifc->ifc_name);
162 
163 		IF_CLONE_LOCK(ifc);
164 		IFC_IFLIST_INSERT(ifc, ifp);
165 		IF_CLONE_UNLOCK(ifc);
166 	}
167 
168 	return (err);
169 }
170 
171 /*
172  * Lookup and destroy a clone network interface.
173  */
174 int
175 if_clone_destroy(const char *name)
176 {
177 	struct if_clone *ifc;
178 	struct ifnet *ifp;
179 
180 	ifp = ifunit(name);
181 	if (ifp == NULL)
182 		return (ENXIO);
183 
184 	/* Find the cloner for this interface */
185 	IF_CLONERS_LOCK();
186 	LIST_FOREACH(ifc, &if_cloners, ifc_list) {
187 		if (strcmp(ifc->ifc_name, ifp->if_dname) == 0) {
188 			break;
189 		}
190 	}
191 	IF_CLONERS_UNLOCK();
192 	if (ifc == NULL)
193 		return (EINVAL);
194 
195 	return (if_clone_destroyif(ifc, ifp));
196 }
197 
198 /*
199  * Destroy a clone network interface.
200  */
201 int
202 if_clone_destroyif(struct if_clone *ifc, struct ifnet *ifp)
203 {
204 	int err;
205 
206 	if (ifc->ifc_destroy == NULL) {
207 		err = EOPNOTSUPP;
208 		goto done;
209 	}
210 
211 	IF_CLONE_LOCK(ifc);
212 	IFC_IFLIST_REMOVE(ifc, ifp);
213 	IF_CLONE_UNLOCK(ifc);
214 
215 	if_delgroup(ifp, ifc->ifc_name);
216 
217 	err =  (*ifc->ifc_destroy)(ifc, ifp);
218 
219 	if (err != 0) {
220 		if_addgroup(ifp, ifc->ifc_name);
221 
222 		IF_CLONE_LOCK(ifc);
223 		IFC_IFLIST_INSERT(ifc, ifp);
224 		IF_CLONE_UNLOCK(ifc);
225 	}
226 
227 done:
228 	return (err);
229 }
230 
231 /*
232  * Register a network interface cloner.
233  */
234 void
235 if_clone_attach(struct if_clone *ifc)
236 {
237 	int len, maxclone;
238 
239 	/*
240 	 * Compute bitmap size and allocate it.
241 	 */
242 	maxclone = ifc->ifc_maxunit + 1;
243 	len = maxclone >> 3;
244 	if ((len << 3) < maxclone)
245 		len++;
246 	ifc->ifc_units = malloc(len, M_CLONE, M_WAITOK | M_ZERO);
247 	ifc->ifc_bmlen = len;
248 	IF_CLONE_LOCK_INIT(ifc);
249 	IF_CLONE_ADDREF(ifc);
250 
251 	IF_CLONERS_LOCK();
252 	LIST_INSERT_HEAD(&if_cloners, ifc, ifc_list);
253 	if_cloners_count++;
254 	IF_CLONERS_UNLOCK();
255 
256 	LIST_INIT(&ifc->ifc_iflist);
257 
258 	if (ifc->ifc_attach != NULL)
259 		(*ifc->ifc_attach)(ifc);
260 	EVENTHANDLER_INVOKE(if_clone_event, ifc);
261 }
262 
263 /*
264  * Unregister a network interface cloner.
265  */
266 void
267 if_clone_detach(struct if_clone *ifc)
268 {
269 	struct ifc_simple_data *ifcs = ifc->ifc_data;
270 
271 	IF_CLONERS_LOCK();
272 	LIST_REMOVE(ifc, ifc_list);
273 	if_cloners_count--;
274 	IF_CLONERS_UNLOCK();
275 
276 	/* Allow all simples to be destroyed */
277 	if (ifc->ifc_attach == ifc_simple_attach)
278 		ifcs->ifcs_minifs = 0;
279 
280 	/* destroy all interfaces for this cloner */
281 	while (!LIST_EMPTY(&ifc->ifc_iflist))
282 		if_clone_destroyif(ifc, LIST_FIRST(&ifc->ifc_iflist));
283 
284 	IF_CLONE_REMREF(ifc);
285 }
286 
287 static void
288 if_clone_free(struct if_clone *ifc)
289 {
290 	for (int bytoff = 0; bytoff < ifc->ifc_bmlen; bytoff++) {
291 		KASSERT(ifc->ifc_units[bytoff] == 0x00,
292 		    ("ifc_units[%d] is not empty", bytoff));
293 	}
294 
295 	KASSERT(LIST_EMPTY(&ifc->ifc_iflist),
296 	    ("%s: ifc_iflist not empty", __func__));
297 
298 	IF_CLONE_LOCK_DESTROY(ifc);
299 	free(ifc->ifc_units, M_CLONE);
300 }
301 
302 /*
303  * Provide list of interface cloners to userspace.
304  */
305 int
306 if_clone_list(struct if_clonereq *ifcr)
307 {
308 	char *buf, *dst, *outbuf = NULL;
309 	struct if_clone *ifc;
310 	int buf_count, count, err = 0;
311 
312 	if (ifcr->ifcr_count < 0)
313 		return (EINVAL);
314 
315 	IF_CLONERS_LOCK();
316 	/*
317 	 * Set our internal output buffer size.  We could end up not
318 	 * reporting a cloner that is added between the unlock and lock
319 	 * below, but that's not a major problem.  Not caping our
320 	 * allocation to the number of cloners actually in the system
321 	 * could be because that would let arbitrary users cause us to
322 	 * allocate abritrary amounts of kernel memory.
323 	 */
324 	buf_count = (if_cloners_count < ifcr->ifcr_count) ?
325 	    if_cloners_count : ifcr->ifcr_count;
326 	IF_CLONERS_UNLOCK();
327 
328 	outbuf = malloc(IFNAMSIZ*buf_count, M_CLONE, M_WAITOK | M_ZERO);
329 
330 	IF_CLONERS_LOCK();
331 
332 	ifcr->ifcr_total = if_cloners_count;
333 	if ((dst = ifcr->ifcr_buffer) == NULL) {
334 		/* Just asking how many there are. */
335 		goto done;
336 	}
337 	count = (if_cloners_count < buf_count) ?
338 	    if_cloners_count : buf_count;
339 
340 	for (ifc = LIST_FIRST(&if_cloners), buf = outbuf;
341 	    ifc != NULL && count != 0;
342 	    ifc = LIST_NEXT(ifc, ifc_list), count--, buf += IFNAMSIZ) {
343 		strlcpy(buf, ifc->ifc_name, IFNAMSIZ);
344 	}
345 
346 done:
347 	IF_CLONERS_UNLOCK();
348 	if (err == 0)
349 		err = copyout(outbuf, dst, buf_count*IFNAMSIZ);
350 	if (outbuf != NULL)
351 		free(outbuf, M_CLONE);
352 	return (err);
353 }
354 
355 /*
356  * A utility function to extract unit numbers from interface names of
357  * the form name###.
358  *
359  * Returns 0 on success and an error on failure.
360  */
361 int
362 ifc_name2unit(const char *name, int *unit)
363 {
364 	const char	*cp;
365 	int		cutoff = INT_MAX / 10;
366 	int		cutlim = INT_MAX % 10;
367 
368 	for (cp = name; *cp != '\0' && (*cp < '0' || *cp > '9'); cp++);
369 	if (*cp == '\0') {
370 		*unit = -1;
371 	} else if (cp[0] == '0' && cp[1] != '\0') {
372 		/* Disallow leading zeroes. */
373 		return (EINVAL);
374 	} else {
375 		for (*unit = 0; *cp != '\0'; cp++) {
376 			if (*cp < '0' || *cp > '9') {
377 				/* Bogus unit number. */
378 				return (EINVAL);
379 			}
380 			if (*unit > cutoff ||
381 			    (*unit == cutoff && *cp - '0' > cutlim))
382 				return (EINVAL);
383 			*unit = (*unit * 10) + (*cp - '0');
384 		}
385 	}
386 
387 	return (0);
388 }
389 
390 int
391 ifc_alloc_unit(struct if_clone *ifc, int *unit)
392 {
393 	int wildcard, bytoff, bitoff;
394 	int err = 0;
395 
396 	IF_CLONE_LOCK(ifc);
397 
398 	bytoff = bitoff = 0;
399 	wildcard = (*unit < 0);
400 	/*
401 	 * Find a free unit if none was given.
402 	 */
403 	if (wildcard) {
404 		while ((bytoff < ifc->ifc_bmlen)
405 		    && (ifc->ifc_units[bytoff] == 0xff))
406 			bytoff++;
407 		if (bytoff >= ifc->ifc_bmlen) {
408 			err = ENOSPC;
409 			goto done;
410 		}
411 		while ((ifc->ifc_units[bytoff] & (1 << bitoff)) != 0)
412 			bitoff++;
413 		*unit = (bytoff << 3) + bitoff;
414 	}
415 
416 	if (*unit > ifc->ifc_maxunit) {
417 		err = ENOSPC;
418 		goto done;
419 	}
420 
421 	if (!wildcard) {
422 		bytoff = *unit >> 3;
423 		bitoff = *unit - (bytoff << 3);
424 	}
425 
426 	if((ifc->ifc_units[bytoff] & (1 << bitoff)) != 0) {
427 		err = EEXIST;
428 		goto done;
429 	}
430 	/*
431 	 * Allocate the unit in the bitmap.
432 	 */
433 	KASSERT((ifc->ifc_units[bytoff] & (1 << bitoff)) == 0,
434 	    ("%s: bit is already set", __func__));
435 	ifc->ifc_units[bytoff] |= (1 << bitoff);
436 	IF_CLONE_ADDREF_LOCKED(ifc);
437 
438 done:
439 	IF_CLONE_UNLOCK(ifc);
440 	return (err);
441 }
442 
443 void
444 ifc_free_unit(struct if_clone *ifc, int unit)
445 {
446 	int bytoff, bitoff;
447 
448 
449 	/*
450 	 * Compute offset in the bitmap and deallocate the unit.
451 	 */
452 	bytoff = unit >> 3;
453 	bitoff = unit - (bytoff << 3);
454 
455 	IF_CLONE_LOCK(ifc);
456 	KASSERT((ifc->ifc_units[bytoff] & (1 << bitoff)) != 0,
457 	    ("%s: bit is already cleared", __func__));
458 	ifc->ifc_units[bytoff] &= ~(1 << bitoff);
459 	IF_CLONE_REMREF_LOCKED(ifc);	/* releases lock */
460 }
461 
462 void
463 ifc_simple_attach(struct if_clone *ifc)
464 {
465 	int err;
466 	int unit;
467 	char name[IFNAMSIZ];
468 	struct ifc_simple_data *ifcs = ifc->ifc_data;
469 
470 	KASSERT(ifcs->ifcs_minifs - 1 <= ifc->ifc_maxunit,
471 	    ("%s: %s requested more units than allowed (%d > %d)",
472 	    __func__, ifc->ifc_name, ifcs->ifcs_minifs,
473 	    ifc->ifc_maxunit + 1));
474 
475 	for (unit = 0; unit < ifcs->ifcs_minifs; unit++) {
476 		snprintf(name, IFNAMSIZ, "%s%d", ifc->ifc_name, unit);
477 		err = if_clone_createif(ifc, name, IFNAMSIZ, NULL);
478 		KASSERT(err == 0,
479 		    ("%s: failed to create required interface %s",
480 		    __func__, name));
481 	}
482 }
483 
484 int
485 ifc_simple_match(struct if_clone *ifc, const char *name)
486 {
487 	const char *cp;
488 	int i;
489 
490 	/* Match the name */
491 	for (cp = name, i = 0; i < strlen(ifc->ifc_name); i++, cp++) {
492 		if (ifc->ifc_name[i] != *cp)
493 			return (0);
494 	}
495 
496 	/* Make sure there's a unit number or nothing after the name */
497 	for (; *cp != '\0'; cp++) {
498 		if (*cp < '0' || *cp > '9')
499 			return (0);
500 	}
501 
502 	return (1);
503 }
504 
505 int
506 ifc_simple_create(struct if_clone *ifc, char *name, size_t len, caddr_t params)
507 {
508 	char *dp;
509 	int wildcard;
510 	int unit;
511 	int err;
512 	struct ifc_simple_data *ifcs = ifc->ifc_data;
513 
514 	err = ifc_name2unit(name, &unit);
515 	if (err != 0)
516 		return (err);
517 
518 	wildcard = (unit < 0);
519 
520 	err = ifc_alloc_unit(ifc, &unit);
521 	if (err != 0)
522 		return (err);
523 
524 	err = ifcs->ifcs_create(ifc, unit, params);
525 	if (err != 0) {
526 		ifc_free_unit(ifc, unit);
527 		return (err);
528 	}
529 
530 	/* In the wildcard case, we need to update the name. */
531 	if (wildcard) {
532 		for (dp = name; *dp != '\0'; dp++);
533 		if (snprintf(dp, len - (dp-name), "%d", unit) >
534 		    len - (dp-name) - 1) {
535 			/*
536 			 * This can only be a programmer error and
537 			 * there's no straightforward way to recover if
538 			 * it happens.
539 			 */
540 			panic("if_clone_create(): interface name too long");
541 		}
542 
543 	}
544 
545 	return (0);
546 }
547 
548 int
549 ifc_simple_destroy(struct if_clone *ifc, struct ifnet *ifp)
550 {
551 	int unit;
552 	struct ifc_simple_data *ifcs = ifc->ifc_data;
553 
554 	unit = ifp->if_dunit;
555 
556 	if (unit < ifcs->ifcs_minifs)
557 		return (EINVAL);
558 
559 	ifcs->ifcs_destroy(ifp);
560 
561 	ifc_free_unit(ifc, unit);
562 
563 	return (0);
564 }
565