1 /*
2 * lib/cache.c Caching Module
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation version 2.1
7 * of the License.
8 *
9 * Copyright (c) 2003-2012 Thomas Graf <tgraf@suug.ch>
10 */
11
12 /**
13 * @ingroup cache_mngt
14 * @defgroup cache Cache
15 *
16 * @code
17 * Cache Management | | Type Specific Cache Operations
18 *
19 * | | +----------------+ +------------+
20 * | request update | | msg_parser |
21 * | | +----------------+ +------------+
22 * +- - - - -^- - - - - - - -^- -|- - - -
23 * nl_cache_update: | | | |
24 * 1) --------- co_request_update ------+ | |
25 * | | |
26 * 2) destroy old cache +----------- pp_cb ---------|---+
27 * | | |
28 * 3) ---------- nl_recvmsgs ----------+ +- cb_valid -+
29 * +--------------+ | | | |
30 * | nl_cache_add |<-----+ + - - -v- -|- - - - - - - - - - -
31 * +--------------+ | | +-------------+
32 * | nl_recvmsgs |
33 * | | +-----|-^-----+
34 * +---v-|---+
35 * | | | nl_recv |
36 * +---------+
37 * | | Core Netlink
38 * @endcode
39 *
40 * Related sections in the development guide:
41 * - @core_doc{core_cache, Caching System}
42 *
43 * @{
44 *
45 * Header
46 * ------
47 * ~~~~{.c}
48 * #include <netlink/cache.h>
49 * ~~~~
50 */
51
52 #include <netlink-private/netlink.h>
53 #include <netlink/netlink.h>
54 #include <netlink/cache.h>
55 #include <netlink/object.h>
56 #include <netlink/hashtable.h>
57 #include <netlink/utils.h>
58
59 /**
60 * @name Access Functions
61 * @{
62 */
63
64 /**
65 * Return the number of items in the cache
66 * @arg cache cache handle
67 */
nl_cache_nitems(struct nl_cache * cache)68 int nl_cache_nitems(struct nl_cache *cache)
69 {
70 return cache->c_nitems;
71 }
72
73 /**
74 * Return the number of items matching a filter in the cache
75 * @arg cache Cache object.
76 * @arg filter Filter object.
77 */
nl_cache_nitems_filter(struct nl_cache * cache,struct nl_object * filter)78 int nl_cache_nitems_filter(struct nl_cache *cache, struct nl_object *filter)
79 {
80 struct nl_object *obj;
81 int nitems = 0;
82
83 if (cache->c_ops == NULL)
84 BUG();
85
86 nl_list_for_each_entry(obj, &cache->c_items, ce_list) {
87 if (filter && !nl_object_match_filter(obj, filter))
88 continue;
89
90 nitems++;
91 }
92
93 return nitems;
94 }
95
96 /**
97 * Returns \b true if the cache is empty.
98 * @arg cache Cache to check
99 * @return \a true if the cache is empty, otherwise \b false is returned.
100 */
nl_cache_is_empty(struct nl_cache * cache)101 int nl_cache_is_empty(struct nl_cache *cache)
102 {
103 return nl_list_empty(&cache->c_items);
104 }
105
106 /**
107 * Return the operations set of the cache
108 * @arg cache cache handle
109 */
nl_cache_get_ops(struct nl_cache * cache)110 struct nl_cache_ops *nl_cache_get_ops(struct nl_cache *cache)
111 {
112 return cache->c_ops;
113 }
114
115 /**
116 * Return the first element in the cache
117 * @arg cache cache handle
118 */
nl_cache_get_first(struct nl_cache * cache)119 struct nl_object *nl_cache_get_first(struct nl_cache *cache)
120 {
121 if (nl_list_empty(&cache->c_items))
122 return NULL;
123
124 return nl_list_entry(cache->c_items.next,
125 struct nl_object, ce_list);
126 }
127
128 /**
129 * Return the last element in the cache
130 * @arg cache cache handle
131 */
nl_cache_get_last(struct nl_cache * cache)132 struct nl_object *nl_cache_get_last(struct nl_cache *cache)
133 {
134 if (nl_list_empty(&cache->c_items))
135 return NULL;
136
137 return nl_list_entry(cache->c_items.prev,
138 struct nl_object, ce_list);
139 }
140
141 /**
142 * Return the next element in the cache
143 * @arg obj current object
144 */
nl_cache_get_next(struct nl_object * obj)145 struct nl_object *nl_cache_get_next(struct nl_object *obj)
146 {
147 if (nl_list_at_tail(obj, &obj->ce_cache->c_items, ce_list))
148 return NULL;
149 else
150 return nl_list_entry(obj->ce_list.next,
151 struct nl_object, ce_list);
152 }
153
154 /**
155 * Return the previous element in the cache
156 * @arg obj current object
157 */
nl_cache_get_prev(struct nl_object * obj)158 struct nl_object *nl_cache_get_prev(struct nl_object *obj)
159 {
160 if (nl_list_at_head(obj, &obj->ce_cache->c_items, ce_list))
161 return NULL;
162 else
163 return nl_list_entry(obj->ce_list.prev,
164 struct nl_object, ce_list);
165 }
166
167 /** @} */
168
169 /**
170 * @name Cache Allocation/Deletion
171 * @{
172 */
173
174 /**
175 * Allocate new cache
176 * @arg ops Cache operations
177 *
178 * Allocate and initialize a new cache based on the cache operations
179 * provided.
180 *
181 * @return Allocated cache or NULL if allocation failed.
182 */
nl_cache_alloc(struct nl_cache_ops * ops)183 struct nl_cache *nl_cache_alloc(struct nl_cache_ops *ops)
184 {
185 struct nl_cache *cache;
186
187 cache = calloc(1, sizeof(*cache));
188 if (!cache)
189 return NULL;
190
191 nl_init_list_head(&cache->c_items);
192 cache->c_ops = ops;
193 cache->c_flags |= ops->co_flags;
194 cache->c_refcnt = 1;
195
196 /*
197 * If object type provides a hash keygen
198 * functions, allocate a hash table for the
199 * cache objects for faster lookups
200 */
201 if (ops->co_obj_ops->oo_keygen) {
202 int hashtable_size;
203
204 if (ops->co_hash_size)
205 hashtable_size = ops->co_hash_size;
206 else
207 hashtable_size = NL_MAX_HASH_ENTRIES;
208
209 cache->hashtable = nl_hash_table_alloc(hashtable_size);
210 }
211
212 NL_DBG(2, "Allocated cache %p <%s>.\n", cache, nl_cache_name(cache));
213
214 return cache;
215 }
216
217 /**
218 * Allocate new cache and fill it
219 * @arg ops Cache operations
220 * @arg sock Netlink socket
221 * @arg result Result pointer
222 *
223 * Allocate new cache and fill it. Equivalent to calling:
224 * @code
225 * cache = nl_cache_alloc(ops);
226 * nl_cache_refill(sock, cache);
227 * @endcode
228 *
229 * @see nl_cache_alloc
230 *
231 * @return 0 on success or a negative error code.
232 */
nl_cache_alloc_and_fill(struct nl_cache_ops * ops,struct nl_sock * sock,struct nl_cache ** result)233 int nl_cache_alloc_and_fill(struct nl_cache_ops *ops, struct nl_sock *sock,
234 struct nl_cache **result)
235 {
236 struct nl_cache *cache;
237 int err;
238
239 if (!(cache = nl_cache_alloc(ops)))
240 return -NLE_NOMEM;
241
242 if (sock && (err = nl_cache_refill(sock, cache)) < 0) {
243 nl_cache_free(cache);
244 return err;
245 }
246
247 *result = cache;
248 return 0;
249 }
250
251 /**
252 * Allocate new cache based on type name
253 * @arg kind Name of cache type
254 * @arg result Result pointer
255 *
256 * Lookup cache ops via nl_cache_ops_lookup() and allocate the cache
257 * by calling nl_cache_alloc(). Stores the allocated cache in the
258 * result pointer provided.
259 *
260 * @see nl_cache_alloc
261 *
262 * @return 0 on success or a negative error code.
263 */
nl_cache_alloc_name(const char * kind,struct nl_cache ** result)264 int nl_cache_alloc_name(const char *kind, struct nl_cache **result)
265 {
266 struct nl_cache_ops *ops;
267 struct nl_cache *cache;
268
269 ops = nl_cache_ops_lookup_safe(kind);
270 if (!ops)
271 return -NLE_NOCACHE;
272
273 cache = nl_cache_alloc(ops);
274 nl_cache_ops_put(ops);
275 if (!cache)
276 return -NLE_NOMEM;
277
278 *result = cache;
279 return 0;
280 }
281
282 /**
283 * Allocate new cache containing a subset of an existing cache
284 * @arg orig Original cache to base new cache on
285 * @arg filter Filter defining the subset to be filled into the new cache
286 *
287 * Allocates a new cache matching the type of the cache specified by
288 * \p orig. Iterates over the \p orig cache applying the specified
289 * \p filter and copies all objects that match to the new cache.
290 *
291 * The copied objects are clones but do not contain a reference to each
292 * other. Later modifications to objects in the original cache will
293 * not affect objects in the new cache.
294 *
295 * @return A newly allocated cache or NULL.
296 */
nl_cache_subset(struct nl_cache * orig,struct nl_object * filter)297 struct nl_cache *nl_cache_subset(struct nl_cache *orig,
298 struct nl_object *filter)
299 {
300 struct nl_cache *cache;
301 struct nl_object *obj;
302
303 if (!filter)
304 BUG();
305
306 cache = nl_cache_alloc(orig->c_ops);
307 if (!cache)
308 return NULL;
309
310 NL_DBG(2, "Filling subset of cache %p <%s> with filter %p into %p\n",
311 orig, nl_cache_name(orig), filter, cache);
312
313 nl_list_for_each_entry(obj, &orig->c_items, ce_list) {
314 if (!nl_object_match_filter(obj, filter))
315 continue;
316
317 nl_cache_add(cache, obj);
318 }
319
320 return cache;
321 }
322
323 /**
324 * Allocate new cache and copy the contents of an existing cache
325 * @arg cache Original cache to base new cache on
326 *
327 * Allocates a new cache matching the type of the cache specified by
328 * \p cache. Iterates over the \p cache cache and copies all objects
329 * to the new cache.
330 *
331 * The copied objects are clones but do not contain a reference to each
332 * other. Later modifications to objects in the original cache will
333 * not affect objects in the new cache.
334 *
335 * @return A newly allocated cache or NULL.
336 */
nl_cache_clone(struct nl_cache * cache)337 struct nl_cache *nl_cache_clone(struct nl_cache *cache)
338 {
339 struct nl_cache_ops *ops = nl_cache_get_ops(cache);
340 struct nl_cache *clone;
341 struct nl_object *obj;
342
343 clone = nl_cache_alloc(ops);
344 if (!clone)
345 return NULL;
346
347 NL_DBG(2, "Cloning %p into %p\n", cache, clone);
348
349 nl_list_for_each_entry(obj, &cache->c_items, ce_list)
350 nl_cache_add(clone, obj);
351
352 return clone;
353 }
354
355 /**
356 * Remove all objects of a cache.
357 * @arg cache Cache to clear
358 *
359 * The objects are unliked/removed from the cache by calling
360 * nl_cache_remove() on each object in the cache. If any of the objects
361 * to not contain any further references to them, those objects will
362 * be freed.
363 *
364 * Unlike with nl_cache_free(), the cache is not freed just emptied.
365 */
nl_cache_clear(struct nl_cache * cache)366 void nl_cache_clear(struct nl_cache *cache)
367 {
368 struct nl_object *obj, *tmp;
369
370 NL_DBG(2, "Clearing cache %p <%s>...\n", cache, nl_cache_name(cache));
371
372 nl_list_for_each_entry_safe(obj, tmp, &cache->c_items, ce_list)
373 nl_cache_remove(obj);
374 }
375
__nl_cache_free(struct nl_cache * cache)376 static void __nl_cache_free(struct nl_cache *cache)
377 {
378 nl_cache_clear(cache);
379
380 if (cache->hashtable)
381 nl_hash_table_free(cache->hashtable);
382
383 NL_DBG(2, "Freeing cache %p <%s>...\n", cache, nl_cache_name(cache));
384 free(cache);
385 }
386
387 /**
388 * Increase reference counter of cache
389 * @arg cache Cache
390 */
nl_cache_get(struct nl_cache * cache)391 void nl_cache_get(struct nl_cache *cache)
392 {
393 cache->c_refcnt++;
394
395 NL_DBG(3, "Incremented cache %p <%s> reference count to %d\n",
396 cache, nl_cache_name(cache), cache->c_refcnt);
397 }
398
399 /**
400 * Free a cache.
401 * @arg cache Cache to free.
402 *
403 * Calls nl_cache_clear() to remove all objects associated with the
404 * cache and frees the cache afterwards.
405 *
406 * @see nl_cache_clear()
407 */
nl_cache_free(struct nl_cache * cache)408 void nl_cache_free(struct nl_cache *cache)
409 {
410 if (!cache)
411 return;
412
413 cache->c_refcnt--;
414
415 NL_DBG(3, "Decremented cache %p <%s> reference count, %d remaining\n",
416 cache, nl_cache_name(cache), cache->c_refcnt);
417
418 if (cache->c_refcnt <= 0)
419 __nl_cache_free(cache);
420 }
421
nl_cache_put(struct nl_cache * cache)422 void nl_cache_put(struct nl_cache *cache)
423 {
424 return nl_cache_free(cache);
425 }
426
427 /** @} */
428
429 /**
430 * @name Cache Modifications
431 * @{
432 */
433
__cache_add(struct nl_cache * cache,struct nl_object * obj)434 static int __cache_add(struct nl_cache *cache, struct nl_object *obj)
435 {
436 int ret;
437
438 obj->ce_cache = cache;
439
440 if (cache->hashtable) {
441 ret = nl_hash_table_add(cache->hashtable, obj);
442 if (ret < 0) {
443 obj->ce_cache = NULL;
444 return ret;
445 }
446 }
447
448 nl_list_add_tail(&obj->ce_list, &cache->c_items);
449 cache->c_nitems++;
450
451 NL_DBG(3, "Added object %p to cache %p <%s>, nitems %d\n",
452 obj, cache, nl_cache_name(cache), cache->c_nitems);
453
454 return 0;
455 }
456
457 /**
458 * Add object to cache.
459 * @arg cache Cache
460 * @arg obj Object to be added to the cache
461 *
462 * Adds the object \p obj to the specified \p cache. In case the object
463 * is already associated with another cache, the object is cloned before
464 * adding it to the cache. In this case, the sole reference to the object
465 * will be the one of the cache. Therefore clearing/freeing the cache
466 * will result in the object being freed again.
467 *
468 * If the object has not been associated with a cache yet, the reference
469 * counter of the object is incremented to account for the additional
470 * reference.
471 *
472 * The type of the object and cache must match, otherwise an error is
473 * returned (-NLE_OBJ_MISMATCH).
474 *
475 * @see nl_cache_move()
476 *
477 * @return 0 or a negative error code.
478 */
nl_cache_add(struct nl_cache * cache,struct nl_object * obj)479 int nl_cache_add(struct nl_cache *cache, struct nl_object *obj)
480 {
481 struct nl_object *new;
482 int ret = 0;
483
484 if (cache->c_ops->co_obj_ops != obj->ce_ops)
485 return -NLE_OBJ_MISMATCH;
486
487 if (!nl_list_empty(&obj->ce_list)) {
488 NL_DBG(3, "Object %p already in cache, cloning new object\n", obj);
489
490 new = nl_object_clone(obj);
491 if (!new)
492 return -NLE_NOMEM;
493 } else {
494 nl_object_get(obj);
495 new = obj;
496 }
497
498 ret = __cache_add(cache, new);
499 if (ret < 0)
500 nl_object_put(new);
501
502 return ret;
503 }
504
505 /**
506 * Move object from one cache to another
507 * @arg cache Cache to move object to.
508 * @arg obj Object subject to be moved
509 *
510 * Removes the the specified object \p obj from its associated cache
511 * and moves it to another cache.
512 *
513 * If the object is not associated with a cache, the function behaves
514 * just like nl_cache_add().
515 *
516 * The type of the object and cache must match, otherwise an error is
517 * returned (-NLE_OBJ_MISMATCH).
518 *
519 * @see nl_cache_add()
520 *
521 * @return 0 on success or a negative error code.
522 */
nl_cache_move(struct nl_cache * cache,struct nl_object * obj)523 int nl_cache_move(struct nl_cache *cache, struct nl_object *obj)
524 {
525 if (cache->c_ops->co_obj_ops != obj->ce_ops)
526 return -NLE_OBJ_MISMATCH;
527
528 NL_DBG(3, "Moving object %p from cache %p to cache %p\n",
529 obj, obj->ce_cache, cache);
530
531 /* Acquire reference, if already in a cache this will be
532 * reverted during removal */
533 nl_object_get(obj);
534
535 if (!nl_list_empty(&obj->ce_list))
536 nl_cache_remove(obj);
537
538 return __cache_add(cache, obj);
539 }
540
541 /**
542 * Remove object from cache.
543 * @arg obj Object to remove from cache
544 *
545 * Removes the object \c obj from the cache it is associated with. The
546 * reference counter of the object will be decremented. If the reference
547 * to the object was the only one remaining, the object will be freed.
548 *
549 * If no cache is associated with the object, this function is a NOP.
550 */
nl_cache_remove(struct nl_object * obj)551 void nl_cache_remove(struct nl_object *obj)
552 {
553 int ret;
554 struct nl_cache *cache = obj->ce_cache;
555
556 if (cache == NULL)
557 return;
558
559 if (cache->hashtable) {
560 ret = nl_hash_table_del(cache->hashtable, obj);
561 if (ret < 0)
562 NL_DBG(2, "Failed to delete %p from cache %p <%s>.\n",
563 obj, cache, nl_cache_name(cache));
564 }
565
566 nl_list_del(&obj->ce_list);
567 obj->ce_cache = NULL;
568 nl_object_put(obj);
569 cache->c_nitems--;
570
571 NL_DBG(2, "Deleted object %p from cache %p <%s>.\n",
572 obj, cache, nl_cache_name(cache));
573 }
574
575 /** @} */
576
577 /**
578 * @name Synchronization
579 * @{
580 */
581
582 /**
583 * Set synchronization arg1 of cache
584 * @arg cache Cache
585 * @arg arg argument
586 *
587 * Synchronization arguments are used to specify filters when
588 * requesting dumps from the kernel.
589 */
nl_cache_set_arg1(struct nl_cache * cache,int arg)590 void nl_cache_set_arg1(struct nl_cache *cache, int arg)
591 {
592 cache->c_iarg1 = arg;
593 }
594
595 /**
596 * Set synchronization arg2 of cache
597 * @arg cache Cache
598 * @arg arg argument
599 *
600 * Synchronization arguments are used to specify filters when
601 * requesting dumps from the kernel.
602 */
nl_cache_set_arg2(struct nl_cache * cache,int arg)603 void nl_cache_set_arg2(struct nl_cache *cache, int arg)
604 {
605 cache->c_iarg2 = arg;
606 }
607
608 /**
609 * Set cache flags
610 * @arg cache Cache
611 * @arg flags Flags
612 */
nl_cache_set_flags(struct nl_cache * cache,unsigned int flags)613 void nl_cache_set_flags(struct nl_cache *cache, unsigned int flags)
614 {
615 cache->c_flags |= flags;
616 }
617
618 /**
619 * Invoke the request-update operation
620 * @arg sk Netlink socket.
621 * @arg cache Cache
622 *
623 * This function causes the \e request-update function of the cache
624 * operations to be invoked. This usually causes a dump request to
625 * be sent over the netlink socket which triggers the kernel to dump
626 * all objects of a specific type to be dumped onto the netlink
627 * socket for pickup.
628 *
629 * The behaviour of this function depends on the implemenation of
630 * the \e request_update function of each individual type of cache.
631 *
632 * This function will not have any effects on the cache (unless the
633 * request_update implementation of the cache operations does so).
634 *
635 * Use nl_cache_pickup() to pick-up (read) the objects from the socket
636 * and fill them into the cache.
637 *
638 * @see nl_cache_pickup(), nl_cache_resync()
639 *
640 * @return 0 on success or a negative error code.
641 */
nl_cache_request_full_dump(struct nl_sock * sk,struct nl_cache * cache)642 static int nl_cache_request_full_dump(struct nl_sock *sk,
643 struct nl_cache *cache)
644 {
645 if (sk->s_proto != cache->c_ops->co_protocol)
646 return -NLE_PROTO_MISMATCH;
647
648 if (cache->c_ops->co_request_update == NULL)
649 return -NLE_OPNOTSUPP;
650
651 NL_DBG(2, "Requesting update from kernel for cache %p <%s>\n",
652 cache, nl_cache_name(cache));
653
654 return cache->c_ops->co_request_update(cache, sk);
655 }
656
657 /** @cond SKIP */
658 struct update_xdata {
659 struct nl_cache_ops *ops;
660 struct nl_parser_param *params;
661 };
662
update_msg_parser(struct nl_msg * msg,void * arg)663 static int update_msg_parser(struct nl_msg *msg, void *arg)
664 {
665 struct update_xdata *x = arg;
666 int ret = 0;
667
668 ret = nl_cache_parse(x->ops, &msg->nm_src, msg->nm_nlh, x->params);
669 if (ret == -NLE_EXIST)
670 return NL_SKIP;
671 else
672 return ret;
673 }
674 /** @endcond */
675
676 /**
677 * Pick-up a netlink request-update with your own parser
678 * @arg sk Netlink socket
679 * @arg cache Cache
680 * @arg param Parser parameters
681 */
__cache_pickup(struct nl_sock * sk,struct nl_cache * cache,struct nl_parser_param * param)682 static int __cache_pickup(struct nl_sock *sk, struct nl_cache *cache,
683 struct nl_parser_param *param)
684 {
685 int err;
686 struct nl_cb *cb;
687 struct update_xdata x = {
688 .ops = cache->c_ops,
689 .params = param,
690 };
691
692 NL_DBG(2, "Picking up answer for cache %p <%s>\n",
693 cache, nl_cache_name(cache));
694
695 cb = nl_cb_clone(sk->s_cb);
696 if (cb == NULL)
697 return -NLE_NOMEM;
698
699 nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, update_msg_parser, &x);
700
701 err = nl_recvmsgs(sk, cb);
702 if (err < 0)
703 NL_DBG(2, "While picking up for %p <%s>, recvmsgs() returned %d: %s\n",
704 cache, nl_cache_name(cache), err, nl_geterror(err));
705
706 nl_cb_put(cb);
707
708 return err;
709 }
710
pickup_cb(struct nl_object * c,struct nl_parser_param * p)711 static int pickup_cb(struct nl_object *c, struct nl_parser_param *p)
712 {
713 struct nl_cache *cache = (struct nl_cache *)p->pp_arg;
714 struct nl_object *old;
715
716 old = nl_cache_search(cache, c);
717 if (old) {
718 if (nl_object_update(old, c) == 0) {
719 nl_object_put(old);
720 return 0;
721 }
722
723 nl_cache_remove(old);
724 nl_object_put(old);
725 }
726
727 return nl_cache_add(cache, c);
728 }
729
730 /**
731 * Pickup a netlink dump response and put it into a cache.
732 * @arg sk Netlink socket.
733 * @arg cache Cache to put items into.
734 *
735 * Waits for netlink messages to arrive, parses them and puts them into
736 * the specified cache. If an old object with same key attributes is
737 * present in the cache, it is replaced with the new object.
738 * If the old object type supports an update operation, an update is
739 * attempted before a replace.
740 *
741 * @return 0 on success or a negative error code.
742 */
nl_cache_pickup(struct nl_sock * sk,struct nl_cache * cache)743 int nl_cache_pickup(struct nl_sock *sk, struct nl_cache *cache)
744 {
745 struct nl_parser_param p = {
746 .pp_cb = pickup_cb,
747 .pp_arg = cache,
748 };
749
750 if (sk->s_proto != cache->c_ops->co_protocol)
751 return -NLE_PROTO_MISMATCH;
752
753 return __cache_pickup(sk, cache, &p);
754 }
755
cache_include(struct nl_cache * cache,struct nl_object * obj,struct nl_msgtype * type,change_func_t cb,void * data)756 static int cache_include(struct nl_cache *cache, struct nl_object *obj,
757 struct nl_msgtype *type, change_func_t cb, void *data)
758 {
759 struct nl_object *old;
760
761 switch (type->mt_act) {
762 case NL_ACT_NEW:
763 case NL_ACT_DEL:
764 old = nl_cache_search(cache, obj);
765 if (old) {
766 /*
767 * Some objects types might support merging the new
768 * object with the old existing cache object.
769 * Handle them first.
770 */
771 if (nl_object_update(old, obj) == 0) {
772 if (cb)
773 cb(cache, old, NL_ACT_CHANGE, data);
774 nl_object_put(old);
775 return 0;
776 }
777
778 nl_cache_remove(old);
779 if (type->mt_act == NL_ACT_DEL) {
780 if (cb)
781 cb(cache, old, NL_ACT_DEL, data);
782 nl_object_put(old);
783 }
784 }
785
786 if (type->mt_act == NL_ACT_NEW) {
787 nl_cache_move(cache, obj);
788 if (old == NULL && cb)
789 cb(cache, obj, NL_ACT_NEW, data);
790 else if (old) {
791 if (nl_object_diff(old, obj) && cb)
792 cb(cache, obj, NL_ACT_CHANGE, data);
793
794 nl_object_put(old);
795 }
796 }
797 break;
798 default:
799 NL_DBG(2, "Unknown action associated to object %p\n", obj);
800 return 0;
801 }
802
803 return 0;
804 }
805
nl_cache_include(struct nl_cache * cache,struct nl_object * obj,change_func_t change_cb,void * data)806 int nl_cache_include(struct nl_cache *cache, struct nl_object *obj,
807 change_func_t change_cb, void *data)
808 {
809 struct nl_cache_ops *ops = cache->c_ops;
810 int i;
811
812 if (ops->co_obj_ops != obj->ce_ops)
813 return -NLE_OBJ_MISMATCH;
814
815 for (i = 0; ops->co_msgtypes[i].mt_id >= 0; i++)
816 if (ops->co_msgtypes[i].mt_id == obj->ce_msgtype)
817 return cache_include(cache, obj, &ops->co_msgtypes[i],
818 change_cb, data);
819
820 NL_DBG(3, "Object %p does not seem to belong to cache %p <%s>\n",
821 obj, cache, nl_cache_name(cache));
822
823 return -NLE_MSGTYPE_NOSUPPORT;
824 }
825
resync_cb(struct nl_object * c,struct nl_parser_param * p)826 static int resync_cb(struct nl_object *c, struct nl_parser_param *p)
827 {
828 struct nl_cache_assoc *ca = p->pp_arg;
829
830 return nl_cache_include(ca->ca_cache, c, ca->ca_change, ca->ca_change_data);
831 }
832
nl_cache_resync(struct nl_sock * sk,struct nl_cache * cache,change_func_t change_cb,void * data)833 int nl_cache_resync(struct nl_sock *sk, struct nl_cache *cache,
834 change_func_t change_cb, void *data)
835 {
836 struct nl_object *obj, *next;
837 struct nl_af_group *grp;
838 struct nl_cache_assoc ca = {
839 .ca_cache = cache,
840 .ca_change = change_cb,
841 .ca_change_data = data,
842 };
843 struct nl_parser_param p = {
844 .pp_cb = resync_cb,
845 .pp_arg = &ca,
846 };
847 int err;
848
849 if (sk->s_proto != cache->c_ops->co_protocol)
850 return -NLE_PROTO_MISMATCH;
851
852 NL_DBG(1, "Resyncing cache %p <%s>...\n", cache, nl_cache_name(cache));
853
854 /* Mark all objects so we can see if some of them are obsolete */
855 nl_cache_mark_all(cache);
856
857 grp = cache->c_ops->co_groups;
858 do {
859 if (grp && grp->ag_group &&
860 (cache->c_flags & NL_CACHE_AF_ITER))
861 nl_cache_set_arg1(cache, grp->ag_family);
862
863 restart:
864 err = nl_cache_request_full_dump(sk, cache);
865 if (err < 0)
866 goto errout;
867
868 err = __cache_pickup(sk, cache, &p);
869 if (err == -NLE_DUMP_INTR)
870 goto restart;
871 else if (err < 0)
872 goto errout;
873
874 if (grp)
875 grp++;
876 } while (grp && grp->ag_group &&
877 (cache->c_flags & NL_CACHE_AF_ITER));
878
879 nl_list_for_each_entry_safe(obj, next, &cache->c_items, ce_list) {
880 if (nl_object_is_marked(obj)) {
881 nl_object_get(obj);
882 nl_cache_remove(obj);
883 if (change_cb)
884 change_cb(cache, obj, NL_ACT_DEL, data);
885 nl_object_put(obj);
886 }
887 }
888
889 NL_DBG(1, "Finished resyncing %p <%s>\n", cache, nl_cache_name(cache));
890
891 err = 0;
892 errout:
893 return err;
894 }
895
896 /** @} */
897
898 /**
899 * @name Parsing
900 * @{
901 */
902
903 /** @cond SKIP */
nl_cache_parse(struct nl_cache_ops * ops,struct sockaddr_nl * who,struct nlmsghdr * nlh,struct nl_parser_param * params)904 int nl_cache_parse(struct nl_cache_ops *ops, struct sockaddr_nl *who,
905 struct nlmsghdr *nlh, struct nl_parser_param *params)
906 {
907 int i, err;
908
909 if (!nlmsg_valid_hdr(nlh, ops->co_hdrsize))
910 return -NLE_MSG_TOOSHORT;
911
912 for (i = 0; ops->co_msgtypes[i].mt_id >= 0; i++) {
913 if (ops->co_msgtypes[i].mt_id == nlh->nlmsg_type) {
914 err = ops->co_msg_parser(ops, who, nlh, params);
915 if (err != -NLE_OPNOTSUPP)
916 goto errout;
917 }
918 }
919
920
921 err = -NLE_MSGTYPE_NOSUPPORT;
922 errout:
923 return err;
924 }
925 /** @endcond */
926
927 /**
928 * Parse a netlink message and add it to the cache.
929 * @arg cache cache to add element to
930 * @arg msg netlink message
931 *
932 * Parses a netlink message by calling the cache specific message parser
933 * and adds the new element to the cache. If an old object with same key
934 * attributes is present in the cache, it is replaced with the new object.
935 * If the old object type supports an update operation, an update is
936 * attempted before a replace.
937 *
938 * @return 0 or a negative error code.
939 */
nl_cache_parse_and_add(struct nl_cache * cache,struct nl_msg * msg)940 int nl_cache_parse_and_add(struct nl_cache *cache, struct nl_msg *msg)
941 {
942 struct nl_parser_param p = {
943 .pp_cb = pickup_cb,
944 .pp_arg = cache,
945 };
946
947 return nl_cache_parse(cache->c_ops, NULL, nlmsg_hdr(msg), &p);
948 }
949
950 /**
951 * (Re)fill a cache with the contents in the kernel.
952 * @arg sk Netlink socket.
953 * @arg cache cache to update
954 *
955 * Clears the specified cache and fills it with the current state in
956 * the kernel.
957 *
958 * @return 0 or a negative error code.
959 */
nl_cache_refill(struct nl_sock * sk,struct nl_cache * cache)960 int nl_cache_refill(struct nl_sock *sk, struct nl_cache *cache)
961 {
962 struct nl_af_group *grp;
963 int err;
964
965 if (sk->s_proto != cache->c_ops->co_protocol)
966 return -NLE_PROTO_MISMATCH;
967
968 nl_cache_clear(cache);
969 grp = cache->c_ops->co_groups;
970 do {
971 if (grp && grp->ag_group &&
972 (cache->c_flags & NL_CACHE_AF_ITER))
973 nl_cache_set_arg1(cache, grp->ag_family);
974
975 restart:
976 err = nl_cache_request_full_dump(sk, cache);
977 if (err < 0)
978 return err;
979
980 NL_DBG(2, "Updating cache %p <%s> for family %u, request sent, waiting for reply\n",
981 cache, nl_cache_name(cache), grp ? grp->ag_family : AF_UNSPEC);
982
983 err = nl_cache_pickup(sk, cache);
984 if (err == -NLE_DUMP_INTR) {
985 NL_DBG(2, "Dump interrupted, restarting!\n");
986 goto restart;
987 } else if (err < 0)
988 break;
989
990 if (grp)
991 grp++;
992 } while (grp && grp->ag_group &&
993 (cache->c_flags & NL_CACHE_AF_ITER));
994
995 return err;
996 }
997
998 /** @} */
999
1000 /**
1001 * @name Utillities
1002 * @{
1003 */
__cache_fast_lookup(struct nl_cache * cache,struct nl_object * needle)1004 static struct nl_object *__cache_fast_lookup(struct nl_cache *cache,
1005 struct nl_object *needle)
1006 {
1007 struct nl_object *obj;
1008
1009 obj = nl_hash_table_lookup(cache->hashtable, needle);
1010 if (obj) {
1011 nl_object_get(obj);
1012 return obj;
1013 }
1014
1015 return NULL;
1016 }
1017
1018 /**
1019 * Search object in cache
1020 * @arg cache Cache
1021 * @arg needle Object to look for.
1022 *
1023 * Searches the cache for an object which matches the object \p needle.
1024 * The function nl_object_identical() is used to determine if the
1025 * objects match. If a matching object is found, the reference counter
1026 * is incremented and the object is returned.
1027 *
1028 * Therefore, if an object is returned, the reference to the object
1029 * must be returned by calling nl_object_put() after usage.
1030 *
1031 * @return Reference to object or NULL if not found.
1032 */
nl_cache_search(struct nl_cache * cache,struct nl_object * needle)1033 struct nl_object *nl_cache_search(struct nl_cache *cache,
1034 struct nl_object *needle)
1035 {
1036 struct nl_object *obj;
1037
1038 if (cache->hashtable)
1039 return __cache_fast_lookup(cache, needle);
1040
1041 nl_list_for_each_entry(obj, &cache->c_items, ce_list) {
1042 if (nl_object_identical(obj, needle)) {
1043 nl_object_get(obj);
1044 return obj;
1045 }
1046 }
1047
1048 return NULL;
1049 }
1050
1051 /**
1052 * Find object in cache
1053 * @arg cache Cache
1054 * @arg filter object acting as a filter
1055 *
1056 * Searches the cache for an object which matches the object filter.
1057 * If the filter attributes matches the object type id attributes,
1058 * and the cache supports hash lookups, a faster hashtable lookup
1059 * is used to return the object. Else, function nl_object_match_filter() is
1060 * used to determine if the objects match. If a matching object is
1061 * found, the reference counter is incremented and the object is returned.
1062 *
1063 * Therefore, if an object is returned, the reference to the object
1064 * must be returned by calling nl_object_put() after usage.
1065 *
1066 * @return Reference to object or NULL if not found.
1067 */
nl_cache_find(struct nl_cache * cache,struct nl_object * filter)1068 struct nl_object *nl_cache_find(struct nl_cache *cache,
1069 struct nl_object *filter)
1070 {
1071 struct nl_object *obj;
1072
1073 if (cache->c_ops == NULL)
1074 BUG();
1075
1076 if ((nl_object_get_id_attrs(filter) == filter->ce_mask)
1077 && cache->hashtable)
1078 return __cache_fast_lookup(cache, filter);
1079
1080 nl_list_for_each_entry(obj, &cache->c_items, ce_list) {
1081 if (nl_object_match_filter(obj, filter)) {
1082 nl_object_get(obj);
1083 return obj;
1084 }
1085 }
1086
1087 return NULL;
1088 }
1089
1090 /**
1091 * Mark all objects of a cache
1092 * @arg cache Cache
1093 *
1094 * Marks all objects of a cache by calling nl_object_mark() on each
1095 * object associated with the cache.
1096 */
nl_cache_mark_all(struct nl_cache * cache)1097 void nl_cache_mark_all(struct nl_cache *cache)
1098 {
1099 struct nl_object *obj;
1100
1101 NL_DBG(2, "Marking all objects in cache %p <%s>\n",
1102 cache, nl_cache_name(cache));
1103
1104 nl_list_for_each_entry(obj, &cache->c_items, ce_list)
1105 nl_object_mark(obj);
1106 }
1107
1108 /** @} */
1109
1110 /**
1111 * @name Dumping
1112 * @{
1113 */
1114
1115 /**
1116 * Dump all elements of a cache.
1117 * @arg cache cache to dump
1118 * @arg params dumping parameters
1119 *
1120 * Dumps all elements of the \a cache to the file descriptor \a fd.
1121 */
nl_cache_dump(struct nl_cache * cache,struct nl_dump_params * params)1122 void nl_cache_dump(struct nl_cache *cache, struct nl_dump_params *params)
1123 {
1124 nl_cache_dump_filter(cache, params, NULL);
1125 }
1126
1127 /**
1128 * Dump all elements of a cache (filtered).
1129 * @arg cache cache to dump
1130 * @arg params dumping parameters (optional)
1131 * @arg filter filter object
1132 *
1133 * Dumps all elements of the \a cache to the file descriptor \a fd
1134 * given they match the given filter \a filter.
1135 */
nl_cache_dump_filter(struct nl_cache * cache,struct nl_dump_params * params,struct nl_object * filter)1136 void nl_cache_dump_filter(struct nl_cache *cache,
1137 struct nl_dump_params *params,
1138 struct nl_object *filter)
1139 {
1140 int type = params ? params->dp_type : NL_DUMP_DETAILS;
1141 struct nl_object_ops *ops;
1142 struct nl_object *obj;
1143
1144 NL_DBG(2, "Dumping cache %p <%s> with filter %p\n",
1145 cache, nl_cache_name(cache), filter);
1146
1147 if (type > NL_DUMP_MAX || type < 0)
1148 BUG();
1149
1150 if (cache->c_ops == NULL)
1151 BUG();
1152
1153 ops = cache->c_ops->co_obj_ops;
1154 if (!ops->oo_dump[type])
1155 return;
1156
1157 if (params && params->dp_buf)
1158 memset(params->dp_buf, 0, params->dp_buflen);
1159
1160 nl_list_for_each_entry(obj, &cache->c_items, ce_list) {
1161 if (filter && !nl_object_match_filter(obj, filter))
1162 continue;
1163
1164 NL_DBG(4, "Dumping object %p...\n", obj);
1165 dump_from_ops(obj, params);
1166 }
1167 }
1168
1169 /** @} */
1170
1171 /**
1172 * @name Iterators
1173 * @{
1174 */
1175
1176 /**
1177 * Call a callback on each element of the cache.
1178 * @arg cache cache to iterate on
1179 * @arg cb callback function
1180 * @arg arg argument passed to callback function
1181 *
1182 * Calls a callback function \a cb on each element of the \a cache.
1183 * The argument \a arg is passed on the callback function.
1184 */
nl_cache_foreach(struct nl_cache * cache,void (* cb)(struct nl_object *,void *),void * arg)1185 void nl_cache_foreach(struct nl_cache *cache,
1186 void (*cb)(struct nl_object *, void *), void *arg)
1187 {
1188 nl_cache_foreach_filter(cache, NULL, cb, arg);
1189 }
1190
1191 /**
1192 * Call a callback on each element of the cache (filtered).
1193 * @arg cache cache to iterate on
1194 * @arg filter filter object
1195 * @arg cb callback function
1196 * @arg arg argument passed to callback function
1197 *
1198 * Calls a callback function \a cb on each element of the \a cache
1199 * that matches the \a filter. The argument \a arg is passed on
1200 * to the callback function.
1201 */
nl_cache_foreach_filter(struct nl_cache * cache,struct nl_object * filter,void (* cb)(struct nl_object *,void *),void * arg)1202 void nl_cache_foreach_filter(struct nl_cache *cache, struct nl_object *filter,
1203 void (*cb)(struct nl_object *, void *), void *arg)
1204 {
1205 struct nl_object *obj, *tmp;
1206
1207 if (cache->c_ops == NULL)
1208 BUG();
1209
1210 nl_list_for_each_entry_safe(obj, tmp, &cache->c_items, ce_list) {
1211 if (filter) {
1212 int diff = nl_object_match_filter(obj, filter);
1213
1214 NL_DBG(3, "%p<->%p object difference: %x\n",
1215 obj, filter, diff);
1216
1217 if (!diff)
1218 continue;
1219 }
1220
1221 /* Caller may hold obj for a long time */
1222 nl_object_get(obj);
1223
1224 cb(obj, arg);
1225
1226 nl_object_put(obj);
1227 }
1228 }
1229
1230 /** @} */
1231
1232 /** @} */
1233