FreeBSD/Linux Kernel Cross Reference
sys/net/if_clone.c
1 /*-
2 * Copyright (c) 2012 Gleb Smirnoff <glebius@FreeBSD.org>
3 * Copyright (c) 1980, 1986, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 4. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 *
30 * @(#)if.c 8.5 (Berkeley) 1/9/95
31 * $FreeBSD: releng/10.1/sys/net/if_clone.c 241650 2012-10-17 21:19:27Z glebius $
32 */
33
34 #include <sys/param.h>
35 #include <sys/malloc.h>
36 #include <sys/limits.h>
37 #include <sys/lock.h>
38 #include <sys/mutex.h>
39 #include <sys/kernel.h>
40 #include <sys/systm.h>
41 #include <sys/types.h>
42 #include <sys/socket.h>
43
44 #include <net/if.h>
45 #include <net/if_clone.h>
46 #include <net/if_var.h>
47 #include <net/radix.h>
48 #include <net/route.h>
49 #include <net/vnet.h>
50
51 /* Current IF_MAXUNIT expands maximum to 5 characters. */
52 #define IFCLOSIZ (IFNAMSIZ - 5)
53
54 /*
55 * Structure describing a `cloning' interface.
56 *
57 * List of locks
58 * (c) const until freeing
59 * (d) driver specific data, may need external protection.
60 * (e) locked by if_cloners_mtx
61 * (i) locked by ifc_mtx mtx
62 */
63 struct if_clone {
64 char ifc_name[IFCLOSIZ]; /* (c) Name of device, e.g. `gif' */
65 struct unrhdr *ifc_unrhdr; /* (c) alloc_unr(9) header */
66 int ifc_maxunit; /* (c) maximum unit number */
67 long ifc_refcnt; /* (i) Reference count. */
68 LIST_HEAD(, ifnet) ifc_iflist; /* (i) List of cloned interfaces */
69 struct mtx ifc_mtx; /* Mutex to protect members. */
70
71 enum { SIMPLE, ADVANCED } ifc_type; /* (c) */
72
73 /* (c) Driver specific cloning functions. Called with no locks held. */
74 union {
75 struct { /* advanced cloner */
76 ifc_match_t *_ifc_match;
77 ifc_create_t *_ifc_create;
78 ifc_destroy_t *_ifc_destroy;
79 } A;
80 struct { /* simple cloner */
81 ifcs_create_t *_ifcs_create;
82 ifcs_destroy_t *_ifcs_destroy;
83 int _ifcs_minifs; /* minimum ifs */
84
85 } S;
86 } U;
87 #define ifc_match U.A._ifc_match
88 #define ifc_create U.A._ifc_create
89 #define ifc_destroy U.A._ifc_destroy
90 #define ifcs_create U.S._ifcs_create
91 #define ifcs_destroy U.S._ifcs_destroy
92 #define ifcs_minifs U.S._ifcs_minifs
93
94 LIST_ENTRY(if_clone) ifc_list; /* (e) On list of cloners */
95 };
96
97 static void if_clone_free(struct if_clone *ifc);
98 static int if_clone_createif(struct if_clone *ifc, char *name, size_t len,
99 caddr_t params);
100
101 static int ifc_simple_match(struct if_clone *, const char *);
102 static int ifc_simple_create(struct if_clone *, char *, size_t, caddr_t);
103 static int ifc_simple_destroy(struct if_clone *, struct ifnet *);
104
105 static struct mtx if_cloners_mtx;
106 static VNET_DEFINE(int, if_cloners_count);
107 VNET_DEFINE(LIST_HEAD(, if_clone), if_cloners);
108
109 #define V_if_cloners_count VNET(if_cloners_count)
110 #define V_if_cloners VNET(if_cloners)
111
112 #define IF_CLONERS_LOCK_INIT() \
113 mtx_init(&if_cloners_mtx, "if_cloners lock", NULL, MTX_DEF)
114 #define IF_CLONERS_LOCK_ASSERT() mtx_assert(&if_cloners_mtx, MA_OWNED)
115 #define IF_CLONERS_LOCK() mtx_lock(&if_cloners_mtx)
116 #define IF_CLONERS_UNLOCK() mtx_unlock(&if_cloners_mtx)
117
118 #define IF_CLONE_LOCK_INIT(ifc) \
119 mtx_init(&(ifc)->ifc_mtx, "if_clone lock", NULL, MTX_DEF)
120 #define IF_CLONE_LOCK_DESTROY(ifc) mtx_destroy(&(ifc)->ifc_mtx)
121 #define IF_CLONE_LOCK_ASSERT(ifc) mtx_assert(&(ifc)->ifc_mtx, MA_OWNED)
122 #define IF_CLONE_LOCK(ifc) mtx_lock(&(ifc)->ifc_mtx)
123 #define IF_CLONE_UNLOCK(ifc) mtx_unlock(&(ifc)->ifc_mtx)
124
125 #define IF_CLONE_ADDREF(ifc) \
126 do { \
127 IF_CLONE_LOCK(ifc); \
128 IF_CLONE_ADDREF_LOCKED(ifc); \
129 IF_CLONE_UNLOCK(ifc); \
130 } while (0)
131 #define IF_CLONE_ADDREF_LOCKED(ifc) \
132 do { \
133 IF_CLONE_LOCK_ASSERT(ifc); \
134 KASSERT((ifc)->ifc_refcnt >= 0, \
135 ("negative refcnt %ld", (ifc)->ifc_refcnt)); \
136 (ifc)->ifc_refcnt++; \
137 } while (0)
138 #define IF_CLONE_REMREF(ifc) \
139 do { \
140 IF_CLONE_LOCK(ifc); \
141 IF_CLONE_REMREF_LOCKED(ifc); \
142 } while (0)
143 #define IF_CLONE_REMREF_LOCKED(ifc) \
144 do { \
145 IF_CLONE_LOCK_ASSERT(ifc); \
146 KASSERT((ifc)->ifc_refcnt > 0, \
147 ("bogus refcnt %ld", (ifc)->ifc_refcnt)); \
148 if (--(ifc)->ifc_refcnt == 0) { \
149 IF_CLONE_UNLOCK(ifc); \
150 if_clone_free(ifc); \
151 } else { \
152 /* silently free the lock */ \
153 IF_CLONE_UNLOCK(ifc); \
154 } \
155 } while (0)
156
157 #define IFC_IFLIST_INSERT(_ifc, _ifp) \
158 LIST_INSERT_HEAD(&_ifc->ifc_iflist, _ifp, if_clones)
159 #define IFC_IFLIST_REMOVE(_ifc, _ifp) \
160 LIST_REMOVE(_ifp, if_clones)
161
162 static MALLOC_DEFINE(M_CLONE, "clone", "interface cloning framework");
163
164 void
165 vnet_if_clone_init(void)
166 {
167
168 LIST_INIT(&V_if_cloners);
169 }
170
171 void
172 if_clone_init(void)
173 {
174
175 IF_CLONERS_LOCK_INIT();
176 }
177
178 /*
179 * Lookup and create a clone network interface.
180 */
181 int
182 if_clone_create(char *name, size_t len, caddr_t params)
183 {
184 struct if_clone *ifc;
185
186 /* Try to find an applicable cloner for this request */
187 IF_CLONERS_LOCK();
188 LIST_FOREACH(ifc, &V_if_cloners, ifc_list)
189 if (ifc->ifc_type == SIMPLE) {
190 if (ifc_simple_match(ifc, name))
191 break;
192 } else {
193 if (ifc->ifc_match(ifc, name))
194 break;
195 }
196 #ifdef VIMAGE
197 if (ifc == NULL && !IS_DEFAULT_VNET(curvnet)) {
198 CURVNET_SET_QUIET(vnet0);
199 LIST_FOREACH(ifc, &V_if_cloners, ifc_list)
200 if (ifc->ifc_type == SIMPLE) {
201 if (ifc_simple_match(ifc, name))
202 break;
203 } else {
204 if (ifc->ifc_match(ifc, name))
205 break;
206 }
207 CURVNET_RESTORE();
208 }
209 #endif
210 IF_CLONERS_UNLOCK();
211
212 if (ifc == NULL)
213 return (EINVAL);
214
215 return (if_clone_createif(ifc, name, len, params));
216 }
217
218 /*
219 * Create a clone network interface.
220 */
221 static int
222 if_clone_createif(struct if_clone *ifc, char *name, size_t len, caddr_t params)
223 {
224 int err;
225 struct ifnet *ifp;
226
227 if (ifunit(name) != NULL)
228 return (EEXIST);
229
230 if (ifc->ifc_type == SIMPLE)
231 err = ifc_simple_create(ifc, name, len, params);
232 else
233 err = (*ifc->ifc_create)(ifc, name, len, params);
234
235 if (!err) {
236 ifp = ifunit(name);
237 if (ifp == NULL)
238 panic("%s: lookup failed for %s", __func__, name);
239
240 if_addgroup(ifp, ifc->ifc_name);
241
242 IF_CLONE_LOCK(ifc);
243 IFC_IFLIST_INSERT(ifc, ifp);
244 IF_CLONE_UNLOCK(ifc);
245 }
246
247 return (err);
248 }
249
250 /*
251 * Lookup and destroy a clone network interface.
252 */
253 int
254 if_clone_destroy(const char *name)
255 {
256 int err;
257 struct if_clone *ifc;
258 struct ifnet *ifp;
259
260 ifp = ifunit_ref(name);
261 if (ifp == NULL)
262 return (ENXIO);
263
264 /* Find the cloner for this interface */
265 IF_CLONERS_LOCK();
266 LIST_FOREACH(ifc, &V_if_cloners, ifc_list) {
267 if (strcmp(ifc->ifc_name, ifp->if_dname) == 0) {
268 break;
269 }
270 }
271 #ifdef VIMAGE
272 if (ifc == NULL && !IS_DEFAULT_VNET(curvnet)) {
273 CURVNET_SET_QUIET(vnet0);
274 LIST_FOREACH(ifc, &V_if_cloners, ifc_list)
275 if (ifc->ifc_type == SIMPLE) {
276 if (ifc_simple_match(ifc, name))
277 break;
278 } else {
279 if (ifc->ifc_match(ifc, name))
280 break;
281 }
282 CURVNET_RESTORE();
283 }
284 #endif
285 IF_CLONERS_UNLOCK();
286 if (ifc == NULL) {
287 if_rele(ifp);
288 return (EINVAL);
289 }
290
291 err = if_clone_destroyif(ifc, ifp);
292 if_rele(ifp);
293 return err;
294 }
295
296 /*
297 * Destroy a clone network interface.
298 */
299 int
300 if_clone_destroyif(struct if_clone *ifc, struct ifnet *ifp)
301 {
302 int err;
303 struct ifnet *ifcifp;
304
305 if (ifc->ifc_type == ADVANCED && ifc->ifc_destroy == NULL)
306 return(EOPNOTSUPP);
307
308 /*
309 * Given that the cloned ifnet might be attached to a different
310 * vnet from where its cloner was registered, we have to
311 * switch to the vnet context of the target vnet.
312 */
313 CURVNET_SET_QUIET(ifp->if_vnet);
314
315 IF_CLONE_LOCK(ifc);
316 LIST_FOREACH(ifcifp, &ifc->ifc_iflist, if_clones) {
317 if (ifcifp == ifp) {
318 IFC_IFLIST_REMOVE(ifc, ifp);
319 break;
320 }
321 }
322 IF_CLONE_UNLOCK(ifc);
323 if (ifcifp == NULL) {
324 CURVNET_RESTORE();
325 return (ENXIO); /* ifp is not on the list. */
326 }
327
328 if_delgroup(ifp, ifc->ifc_name);
329
330 if (ifc->ifc_type == SIMPLE)
331 err = ifc_simple_destroy(ifc, ifp);
332 else
333 err = (*ifc->ifc_destroy)(ifc, ifp);
334
335 if (err != 0) {
336 if_addgroup(ifp, ifc->ifc_name);
337
338 IF_CLONE_LOCK(ifc);
339 IFC_IFLIST_INSERT(ifc, ifp);
340 IF_CLONE_UNLOCK(ifc);
341 }
342 CURVNET_RESTORE();
343 return (err);
344 }
345
346 static struct if_clone *
347 if_clone_alloc(const char *name, int maxunit)
348 {
349 struct if_clone *ifc;
350
351 KASSERT(name != NULL, ("%s: no name\n", __func__));
352
353 ifc = malloc(sizeof(struct if_clone), M_CLONE, M_WAITOK | M_ZERO);
354 strncpy(ifc->ifc_name, name, IFCLOSIZ-1);
355 IF_CLONE_LOCK_INIT(ifc);
356 IF_CLONE_ADDREF(ifc);
357 ifc->ifc_maxunit = maxunit ? maxunit : IF_MAXUNIT;
358 ifc->ifc_unrhdr = new_unrhdr(0, ifc->ifc_maxunit, &ifc->ifc_mtx);
359 LIST_INIT(&ifc->ifc_iflist);
360
361 return (ifc);
362 }
363
364 static int
365 if_clone_attach(struct if_clone *ifc)
366 {
367 struct if_clone *ifc1;
368
369 IF_CLONERS_LOCK();
370 LIST_FOREACH(ifc1, &V_if_cloners, ifc_list)
371 if (strcmp(ifc->ifc_name, ifc1->ifc_name) == 0) {
372 IF_CLONERS_UNLOCK();
373 IF_CLONE_REMREF(ifc);
374 return (EEXIST);
375 }
376 LIST_INSERT_HEAD(&V_if_cloners, ifc, ifc_list);
377 V_if_cloners_count++;
378 IF_CLONERS_UNLOCK();
379
380 return (0);
381 }
382
383 struct if_clone *
384 if_clone_advanced(const char *name, u_int maxunit, ifc_match_t match,
385 ifc_create_t create, ifc_destroy_t destroy)
386 {
387 struct if_clone *ifc;
388
389 ifc = if_clone_alloc(name, maxunit);
390 ifc->ifc_type = ADVANCED;
391 ifc->ifc_match = match;
392 ifc->ifc_create = create;
393 ifc->ifc_destroy = destroy;
394
395 if (if_clone_attach(ifc) != 0) {
396 if_clone_free(ifc);
397 return (NULL);
398 }
399
400 EVENTHANDLER_INVOKE(if_clone_event, ifc);
401
402 return (ifc);
403 }
404
405 struct if_clone *
406 if_clone_simple(const char *name, ifcs_create_t create, ifcs_destroy_t destroy,
407 u_int minifs)
408 {
409 struct if_clone *ifc;
410 u_int unit;
411
412 ifc = if_clone_alloc(name, 0);
413 ifc->ifc_type = SIMPLE;
414 ifc->ifcs_create = create;
415 ifc->ifcs_destroy = destroy;
416 ifc->ifcs_minifs = minifs;
417
418 if (if_clone_attach(ifc) != 0) {
419 if_clone_free(ifc);
420 return (NULL);
421 }
422
423 for (unit = 0; unit < minifs; unit++) {
424 char name[IFNAMSIZ];
425 int error;
426
427 snprintf(name, IFNAMSIZ, "%s%d", ifc->ifc_name, unit);
428 error = if_clone_createif(ifc, name, IFNAMSIZ, NULL);
429 KASSERT(error == 0,
430 ("%s: failed to create required interface %s",
431 __func__, name));
432 }
433
434 EVENTHANDLER_INVOKE(if_clone_event, ifc);
435
436 return (ifc);
437 }
438
439 /*
440 * Unregister a network interface cloner.
441 */
442 void
443 if_clone_detach(struct if_clone *ifc)
444 {
445
446 IF_CLONERS_LOCK();
447 LIST_REMOVE(ifc, ifc_list);
448 V_if_cloners_count--;
449 IF_CLONERS_UNLOCK();
450
451 /* Allow all simples to be destroyed */
452 if (ifc->ifc_type == SIMPLE)
453 ifc->ifcs_minifs = 0;
454
455 /* destroy all interfaces for this cloner */
456 while (!LIST_EMPTY(&ifc->ifc_iflist))
457 if_clone_destroyif(ifc, LIST_FIRST(&ifc->ifc_iflist));
458
459 IF_CLONE_REMREF(ifc);
460 }
461
462 static void
463 if_clone_free(struct if_clone *ifc)
464 {
465
466 KASSERT(LIST_EMPTY(&ifc->ifc_iflist),
467 ("%s: ifc_iflist not empty", __func__));
468
469 IF_CLONE_LOCK_DESTROY(ifc);
470 delete_unrhdr(ifc->ifc_unrhdr);
471 free(ifc, M_CLONE);
472 }
473
474 /*
475 * Provide list of interface cloners to userspace.
476 */
477 int
478 if_clone_list(struct if_clonereq *ifcr)
479 {
480 char *buf, *dst, *outbuf = NULL;
481 struct if_clone *ifc;
482 int buf_count, count, err = 0;
483
484 if (ifcr->ifcr_count < 0)
485 return (EINVAL);
486
487 IF_CLONERS_LOCK();
488 /*
489 * Set our internal output buffer size. We could end up not
490 * reporting a cloner that is added between the unlock and lock
491 * below, but that's not a major problem. Not caping our
492 * allocation to the number of cloners actually in the system
493 * could be because that would let arbitrary users cause us to
494 * allocate abritrary amounts of kernel memory.
495 */
496 buf_count = (V_if_cloners_count < ifcr->ifcr_count) ?
497 V_if_cloners_count : ifcr->ifcr_count;
498 IF_CLONERS_UNLOCK();
499
500 outbuf = malloc(IFNAMSIZ*buf_count, M_CLONE, M_WAITOK | M_ZERO);
501
502 IF_CLONERS_LOCK();
503
504 ifcr->ifcr_total = V_if_cloners_count;
505 if ((dst = ifcr->ifcr_buffer) == NULL) {
506 /* Just asking how many there are. */
507 goto done;
508 }
509 count = (V_if_cloners_count < buf_count) ?
510 V_if_cloners_count : buf_count;
511
512 for (ifc = LIST_FIRST(&V_if_cloners), buf = outbuf;
513 ifc != NULL && count != 0;
514 ifc = LIST_NEXT(ifc, ifc_list), count--, buf += IFNAMSIZ) {
515 strlcpy(buf, ifc->ifc_name, IFNAMSIZ);
516 }
517
518 done:
519 IF_CLONERS_UNLOCK();
520 if (err == 0)
521 err = copyout(outbuf, dst, buf_count*IFNAMSIZ);
522 if (outbuf != NULL)
523 free(outbuf, M_CLONE);
524 return (err);
525 }
526
527 /*
528 * A utility function to extract unit numbers from interface names of
529 * the form name###.
530 *
531 * Returns 0 on success and an error on failure.
532 */
533 int
534 ifc_name2unit(const char *name, int *unit)
535 {
536 const char *cp;
537 int cutoff = INT_MAX / 10;
538 int cutlim = INT_MAX % 10;
539
540 for (cp = name; *cp != '\0' && (*cp < '' || *cp > '9'); cp++);
541 if (*cp == '\0') {
542 *unit = -1;
543 } else if (cp[0] == '' && cp[1] != '\0') {
544 /* Disallow leading zeroes. */
545 return (EINVAL);
546 } else {
547 for (*unit = 0; *cp != '\0'; cp++) {
548 if (*cp < '' || *cp > '9') {
549 /* Bogus unit number. */
550 return (EINVAL);
551 }
552 if (*unit > cutoff ||
553 (*unit == cutoff && *cp - '' > cutlim))
554 return (EINVAL);
555 *unit = (*unit * 10) + (*cp - '');
556 }
557 }
558
559 return (0);
560 }
561
562 int
563 ifc_alloc_unit(struct if_clone *ifc, int *unit)
564 {
565 char name[IFNAMSIZ];
566 int wildcard;
567
568 wildcard = (*unit < 0);
569 retry:
570 if (*unit > ifc->ifc_maxunit)
571 return (ENOSPC);
572 if (*unit < 0) {
573 *unit = alloc_unr(ifc->ifc_unrhdr);
574 if (*unit == -1)
575 return (ENOSPC);
576 } else {
577 *unit = alloc_unr_specific(ifc->ifc_unrhdr, *unit);
578 if (*unit == -1) {
579 if (wildcard) {
580 (*unit)++;
581 goto retry;
582 } else
583 return (EEXIST);
584 }
585 }
586
587 snprintf(name, IFNAMSIZ, "%s%d", ifc->ifc_name, *unit);
588 if (ifunit(name) != NULL) {
589 free_unr(ifc->ifc_unrhdr, *unit);
590 if (wildcard) {
591 (*unit)++;
592 goto retry;
593 } else
594 return (EEXIST);
595 }
596
597 IF_CLONE_ADDREF(ifc);
598
599 return (0);
600 }
601
602 void
603 ifc_free_unit(struct if_clone *ifc, int unit)
604 {
605
606 free_unr(ifc->ifc_unrhdr, unit);
607 IF_CLONE_REMREF(ifc);
608 }
609
610 static int
611 ifc_simple_match(struct if_clone *ifc, const char *name)
612 {
613 const char *cp;
614 int i;
615
616 /* Match the name */
617 for (cp = name, i = 0; i < strlen(ifc->ifc_name); i++, cp++) {
618 if (ifc->ifc_name[i] != *cp)
619 return (0);
620 }
621
622 /* Make sure there's a unit number or nothing after the name */
623 for (; *cp != '\0'; cp++) {
624 if (*cp < '' || *cp > '9')
625 return (0);
626 }
627
628 return (1);
629 }
630
631 static int
632 ifc_simple_create(struct if_clone *ifc, char *name, size_t len, caddr_t params)
633 {
634 char *dp;
635 int wildcard;
636 int unit;
637 int err;
638
639 err = ifc_name2unit(name, &unit);
640 if (err != 0)
641 return (err);
642
643 wildcard = (unit < 0);
644
645 err = ifc_alloc_unit(ifc, &unit);
646 if (err != 0)
647 return (err);
648
649 err = ifc->ifcs_create(ifc, unit, params);
650 if (err != 0) {
651 ifc_free_unit(ifc, unit);
652 return (err);
653 }
654
655 /* In the wildcard case, we need to update the name. */
656 if (wildcard) {
657 for (dp = name; *dp != '\0'; dp++);
658 if (snprintf(dp, len - (dp-name), "%d", unit) >
659 len - (dp-name) - 1) {
660 /*
661 * This can only be a programmer error and
662 * there's no straightforward way to recover if
663 * it happens.
664 */
665 panic("if_clone_create(): interface name too long");
666 }
667
668 }
669
670 return (0);
671 }
672
673 static int
674 ifc_simple_destroy(struct if_clone *ifc, struct ifnet *ifp)
675 {
676 int unit;
677
678 unit = ifp->if_dunit;
679
680 if (unit < ifc->ifcs_minifs)
681 return (EINVAL);
682
683 ifc->ifcs_destroy(ifp);
684
685 ifc_free_unit(ifc, unit);
686
687 return (0);
688 }
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