FreeBSD/Linux Kernel Cross Reference
sys/net/if_clone.c
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: src/sys/net/if_clone.c,v 1.12 2008/09/20 19:38:37 thompsa Exp $
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 < '' || *cp > '9'); cp++);
369 if (*cp == '\0') {
370 *unit = -1;
371 } else if (cp[0] == '' && cp[1] != '\0') {
372 /* Disallow leading zeroes. */
373 return (EINVAL);
374 } else {
375 for (*unit = 0; *cp != '\0'; cp++) {
376 if (*cp < '' || *cp > '9') {
377 /* Bogus unit number. */
378 return (EINVAL);
379 }
380 if (*unit > cutoff ||
381 (*unit == cutoff && *cp - '' > cutlim))
382 return (EINVAL);
383 *unit = (*unit * 10) + (*cp - '');
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 < '' || *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
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