2 * lib/cache.c Caching Module
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
9 * Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
14 * @defgroup cache Cache
17 * Cache Management | | Type Specific Cache Operations
19 * | | +----------------+ +------------+
20 * | request update | | msg_parser |
21 * | | +----------------+ +------------+
22 * +- - - - -^- - - - - - - -^- -|- - - -
23 * nl_cache_update: | | | |
24 * 1) --------- co_request_update ------+ | |
26 * 2) destroy old cache +----------- pp_cb ---------|---+
28 * 3) ---------- nl_recvmsgs ----------+ +- cb_valid -+
29 * +--------------+ | | | |
30 * | nl_cache_add |<-----+ + - - -v- -|- - - - - - - - - - -
31 * +--------------+ | | +-------------+
43 #include <netlink-local.h>
44 #include <netlink/netlink.h>
45 #include <netlink/cache.h>
46 #include <netlink/object.h>
47 #include <netlink/utils.h>
50 * @name Access Functions
55 * Return the number of items in the cache
56 * @arg cache cache handle
58 int nl_cache_nitems(struct nl_cache *cache)
60 return cache->c_nitems;
64 * Return the number of items matching a filter in the cache
65 * @arg cache Cache object.
66 * @arg filter Filter object.
68 int nl_cache_nitems_filter(struct nl_cache *cache, struct nl_object *filter)
70 struct nl_object_ops *ops;
71 struct nl_object *obj;
74 if (cache->c_ops == NULL)
77 ops = cache->c_ops->co_obj_ops;
79 nl_list_for_each_entry(obj, &cache->c_items, ce_list) {
80 if (filter && !nl_object_match_filter(obj, filter))
90 * Returns \b true if the cache is empty.
91 * @arg cache Cache to check
92 * @return \a true if the cache is empty, otherwise \b false is returned.
94 int nl_cache_is_empty(struct nl_cache *cache)
96 return nl_list_empty(&cache->c_items);
100 * Return the operations set of the cache
101 * @arg cache cache handle
103 struct nl_cache_ops *nl_cache_get_ops(struct nl_cache *cache)
109 * Return the first element in the cache
110 * @arg cache cache handle
112 struct nl_object *nl_cache_get_first(struct nl_cache *cache)
114 if (nl_list_empty(&cache->c_items))
117 return nl_list_entry(cache->c_items.next,
118 struct nl_object, ce_list);
122 * Return the last element in the cache
123 * @arg cache cache handle
125 struct nl_object *nl_cache_get_last(struct nl_cache *cache)
127 if (nl_list_empty(&cache->c_items))
130 return nl_list_entry(cache->c_items.prev,
131 struct nl_object, ce_list);
135 * Return the next element in the cache
136 * @arg obj current object
138 struct nl_object *nl_cache_get_next(struct nl_object *obj)
140 if (nl_list_at_tail(obj, &obj->ce_cache->c_items, ce_list))
143 return nl_list_entry(obj->ce_list.next,
144 struct nl_object, ce_list);
148 * Return the previous element in the cache
149 * @arg obj current object
151 struct nl_object *nl_cache_get_prev(struct nl_object *obj)
153 if (nl_list_at_head(obj, &obj->ce_cache->c_items, ce_list))
156 return nl_list_entry(obj->ce_list.prev,
157 struct nl_object, ce_list);
163 * @name Cache Creation/Deletion
168 * Allocate an empty cache
169 * @arg ops cache operations to base the cache on
171 * @return A newly allocated and initialized cache.
173 struct nl_cache *nl_cache_alloc(struct nl_cache_ops *ops)
175 struct nl_cache *cache;
177 cache = calloc(1, sizeof(*cache));
181 nl_init_list_head(&cache->c_items);
184 NL_DBG(2, "Allocated cache %p <%s>.\n", cache, nl_cache_name(cache));
189 int nl_cache_alloc_and_fill(struct nl_cache_ops *ops, struct nl_sock *sock,
190 struct nl_cache **result)
192 struct nl_cache *cache;
195 if (!(cache = nl_cache_alloc(ops)))
198 if (sock && (err = nl_cache_refill(sock, cache)) < 0) {
199 nl_cache_free(cache);
208 * Allocate an empty cache based on type name
209 * @arg kind Name of cache type
210 * @return A newly allocated and initialized cache.
212 int nl_cache_alloc_name(const char *kind, struct nl_cache **result)
214 struct nl_cache_ops *ops;
215 struct nl_cache *cache;
217 ops = nl_cache_ops_lookup(kind);
221 if (!(cache = nl_cache_alloc(ops)))
229 * Allocate a new cache containing a subset of a cache
230 * @arg orig Original cache to be based on
231 * @arg filter Filter defining the subset to be filled into new cache
232 * @return A newly allocated cache or NULL.
234 struct nl_cache *nl_cache_subset(struct nl_cache *orig,
235 struct nl_object *filter)
237 struct nl_cache *cache;
238 struct nl_object_ops *ops;
239 struct nl_object *obj;
244 cache = nl_cache_alloc(orig->c_ops);
248 ops = orig->c_ops->co_obj_ops;
250 nl_list_for_each_entry(obj, &orig->c_items, ce_list) {
251 if (!nl_object_match_filter(obj, filter))
254 nl_cache_add(cache, obj);
262 * @arg cache cache to clear
264 * Removes all elements of a cache.
266 void nl_cache_clear(struct nl_cache *cache)
268 struct nl_object *obj, *tmp;
270 NL_DBG(1, "Clearing cache %p <%s>...\n", cache, nl_cache_name(cache));
272 nl_list_for_each_entry_safe(obj, tmp, &cache->c_items, ce_list)
273 nl_cache_remove(obj);
278 * @arg cache Cache to free.
280 * Removes all elements of a cache and frees all memory.
282 * @note Use this function if you are working with allocated caches.
284 void nl_cache_free(struct nl_cache *cache)
289 nl_cache_clear(cache);
290 NL_DBG(1, "Freeing cache %p <%s>...\n", cache, nl_cache_name(cache));
297 * @name Cache Modifications
301 static int __cache_add(struct nl_cache *cache, struct nl_object *obj)
303 obj->ce_cache = cache;
305 nl_list_add_tail(&obj->ce_list, &cache->c_items);
308 NL_DBG(1, "Added %p to cache %p <%s>.\n",
309 obj, cache, nl_cache_name(cache));
315 * Add object to a cache.
316 * @arg cache Cache to add object to
317 * @arg obj Object to be added to the cache
319 * Adds the given object to the specified cache. The object is cloned
320 * if it has been added to another cache already.
322 * @return 0 or a negative error code.
324 int nl_cache_add(struct nl_cache *cache, struct nl_object *obj)
326 struct nl_object *new;
328 if (cache->c_ops->co_obj_ops != obj->ce_ops)
329 return -NLE_OBJ_MISMATCH;
331 if (!nl_list_empty(&obj->ce_list)) {
332 new = nl_object_clone(obj);
340 return __cache_add(cache, new);
344 * Move object from one cache to another
345 * @arg cache Cache to move object to.
346 * @arg obj Object subject to be moved
348 * Removes the given object from its associated cache if needed
349 * and adds it to the new cache.
351 * @return 0 on success or a negative error code.
353 int nl_cache_move(struct nl_cache *cache, struct nl_object *obj)
355 if (cache->c_ops->co_obj_ops != obj->ce_ops)
356 return -NLE_OBJ_MISMATCH;
358 NL_DBG(3, "Moving object %p to cache %p\n", obj, cache);
360 /* Acquire reference, if already in a cache this will be
361 * reverted during removal */
364 if (!nl_list_empty(&obj->ce_list))
365 nl_cache_remove(obj);
367 return __cache_add(cache, obj);
371 * Removes an object from a cache.
372 * @arg obj Object to remove from its cache
374 * Removes the object \c obj from the cache it is assigned to, since
375 * an object can only be assigned to one cache at a time, the cache
376 * must ne be passed along with it.
378 void nl_cache_remove(struct nl_object *obj)
380 struct nl_cache *cache = obj->ce_cache;
385 nl_list_del(&obj->ce_list);
386 obj->ce_cache = NULL;
390 NL_DBG(1, "Deleted %p from cache %p <%s>.\n",
391 obj, cache, nl_cache_name(cache));
395 * Search for an object in a cache
396 * @arg cache Cache to search in.
397 * @arg needle Object to look for.
399 * Iterates over the cache and looks for an object with identical
400 * identifiers as the needle.
402 * @return Reference to object or NULL if not found.
403 * @note The returned object must be returned via nl_object_put().
405 struct nl_object *nl_cache_search(struct nl_cache *cache,
406 struct nl_object *needle)
408 struct nl_object *obj;
410 nl_list_for_each_entry(obj, &cache->c_items, ce_list) {
411 if (nl_object_identical(obj, needle)) {
424 * @name Synchronization
429 * Request a full dump from the kernel to fill a cache
430 * @arg sk Netlink socket.
431 * @arg cache Cache subjected to be filled.
433 * Send a dumping request to the kernel causing it to dump all objects
434 * related to the specified cache to the netlink socket.
436 * Use nl_cache_pickup() to read the objects from the socket and fill them
439 int nl_cache_request_full_dump(struct nl_sock *sk, struct nl_cache *cache)
441 NL_DBG(2, "Requesting dump from kernel for cache %p <%s>...\n",
442 cache, nl_cache_name(cache));
444 if (cache->c_ops->co_request_update == NULL)
445 return -NLE_OPNOTSUPP;
447 return cache->c_ops->co_request_update(cache, sk);
451 struct update_xdata {
452 struct nl_cache_ops *ops;
453 struct nl_parser_param *params;
456 static int update_msg_parser(struct nl_msg *msg, void *arg)
458 struct update_xdata *x = arg;
460 return nl_cache_parse(x->ops, &msg->nm_src, msg->nm_nlh, x->params);
464 int __cache_pickup(struct nl_sock *sk, struct nl_cache *cache,
465 struct nl_parser_param *param)
469 struct update_xdata x = {
474 NL_DBG(1, "Picking up answer for cache %p <%s>...\n",
475 cache, nl_cache_name(cache));
477 cb = nl_cb_clone(sk->s_cb);
481 nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, update_msg_parser, &x);
483 err = nl_recvmsgs(sk, cb);
485 NL_DBG(2, "While picking up for %p <%s>, recvmsgs() returned " \
486 "%d: %s", cache, nl_cache_name(cache),
487 err, nl_geterror(err));
494 static int pickup_cb(struct nl_object *c, struct nl_parser_param *p)
496 return nl_cache_add((struct nl_cache *) p->pp_arg, c);
500 * Pickup a netlink dump response and put it into a cache.
501 * @arg sk Netlink socket.
502 * @arg cache Cache to put items into.
504 * Waits for netlink messages to arrive, parses them and puts them into
505 * the specified cache.
507 * @return 0 on success or a negative error code.
509 int nl_cache_pickup(struct nl_sock *sk, struct nl_cache *cache)
511 struct nl_parser_param p = {
516 return __cache_pickup(sk, cache, &p);
519 static int cache_include(struct nl_cache *cache, struct nl_object *obj,
520 struct nl_msgtype *type, change_func_t cb, void *data)
522 struct nl_object *old;
524 switch (type->mt_act) {
527 old = nl_cache_search(cache, obj);
529 nl_cache_remove(old);
530 if (type->mt_act == NL_ACT_DEL) {
532 cb(cache, old, NL_ACT_DEL, data);
537 if (type->mt_act == NL_ACT_NEW) {
538 nl_cache_move(cache, obj);
539 if (old == NULL && cb)
540 cb(cache, obj, NL_ACT_NEW, data);
542 if (nl_object_diff(old, obj) && cb)
543 cb(cache, obj, NL_ACT_CHANGE, data);
550 NL_DBG(2, "Unknown action associated to object %p\n", obj);
557 int nl_cache_include(struct nl_cache *cache, struct nl_object *obj,
558 change_func_t change_cb, void *data)
560 struct nl_cache_ops *ops = cache->c_ops;
563 if (ops->co_obj_ops != obj->ce_ops)
564 return -NLE_OBJ_MISMATCH;
566 for (i = 0; ops->co_msgtypes[i].mt_id >= 0; i++)
567 if (ops->co_msgtypes[i].mt_id == obj->ce_msgtype)
568 return cache_include(cache, obj, &ops->co_msgtypes[i],
571 return -NLE_MSGTYPE_NOSUPPORT;
574 static int resync_cb(struct nl_object *c, struct nl_parser_param *p)
576 struct nl_cache_assoc *ca = p->pp_arg;
578 return nl_cache_include(ca->ca_cache, c, ca->ca_change, ca->ca_change_data);
581 int nl_cache_resync(struct nl_sock *sk, struct nl_cache *cache,
582 change_func_t change_cb, void *data)
584 struct nl_object *obj, *next;
585 struct nl_cache_assoc ca = {
587 .ca_change = change_cb,
588 .ca_change_data = data,
590 struct nl_parser_param p = {
596 NL_DBG(1, "Resyncing cache %p <%s>...\n", cache, nl_cache_name(cache));
598 /* Mark all objects so we can see if some of them are obsolete */
599 nl_cache_mark_all(cache);
601 err = nl_cache_request_full_dump(sk, cache);
605 err = __cache_pickup(sk, cache, &p);
609 nl_list_for_each_entry_safe(obj, next, &cache->c_items, ce_list) {
610 if (nl_object_is_marked(obj)) {
612 nl_cache_remove(obj);
614 change_cb(cache, obj, NL_ACT_DEL, data);
619 NL_DBG(1, "Finished resyncing %p <%s>\n", cache, nl_cache_name(cache));
634 int nl_cache_parse(struct nl_cache_ops *ops, struct sockaddr_nl *who,
635 struct nlmsghdr *nlh, struct nl_parser_param *params)
639 if (!nlmsg_valid_hdr(nlh, ops->co_hdrsize))
640 return -NLE_MSG_TOOSHORT;
642 for (i = 0; ops->co_msgtypes[i].mt_id >= 0; i++) {
643 if (ops->co_msgtypes[i].mt_id == nlh->nlmsg_type) {
644 err = ops->co_msg_parser(ops, who, nlh, params);
645 if (err != -NLE_OPNOTSUPP)
651 err = -NLE_MSGTYPE_NOSUPPORT;
658 * Parse a netlink message and add it to the cache.
659 * @arg cache cache to add element to
660 * @arg msg netlink message
662 * Parses a netlink message by calling the cache specific message parser
663 * and adds the new element to the cache.
665 * @return 0 or a negative error code.
667 int nl_cache_parse_and_add(struct nl_cache *cache, struct nl_msg *msg)
669 struct nl_parser_param p = {
674 return nl_cache_parse(cache->c_ops, NULL, nlmsg_hdr(msg), &p);
678 * (Re)fill a cache with the contents in the kernel.
679 * @arg sk Netlink socket.
680 * @arg cache cache to update
682 * Clears the specified cache and fills it with the current state in
685 * @return 0 or a negative error code.
687 int nl_cache_refill(struct nl_sock *sk, struct nl_cache *cache)
691 err = nl_cache_request_full_dump(sk, cache);
695 NL_DBG(2, "Upading cache %p <%s>, request sent, waiting for dump...\n",
696 cache, nl_cache_name(cache));
697 nl_cache_clear(cache);
699 return nl_cache_pickup(sk, cache);
710 * Mark all objects in a cache
711 * @arg cache Cache to mark all objects in
713 void nl_cache_mark_all(struct nl_cache *cache)
715 struct nl_object *obj;
717 NL_DBG(2, "Marking all objects in cache %p <%s>...\n",
718 cache, nl_cache_name(cache));
720 nl_list_for_each_entry(obj, &cache->c_items, ce_list)
732 * Dump all elements of a cache.
733 * @arg cache cache to dump
734 * @arg params dumping parameters
736 * Dumps all elements of the \a cache to the file descriptor \a fd.
738 void nl_cache_dump(struct nl_cache *cache, struct nl_dump_params *params)
740 nl_cache_dump_filter(cache, params, NULL);
744 * Dump all elements of a cache (filtered).
745 * @arg cache cache to dump
746 * @arg params dumping parameters (optional)
747 * @arg filter filter object
749 * Dumps all elements of the \a cache to the file descriptor \a fd
750 * given they match the given filter \a filter.
752 void nl_cache_dump_filter(struct nl_cache *cache,
753 struct nl_dump_params *params,
754 struct nl_object *filter)
756 int type = params ? params->dp_type : NL_DUMP_DETAILS;
757 struct nl_object_ops *ops;
758 struct nl_object *obj;
760 NL_DBG(2, "Dumping cache %p <%s> filter %p\n",
761 cache, nl_cache_name(cache), filter);
763 if (type > NL_DUMP_MAX || type < 0)
766 if (cache->c_ops == NULL)
769 ops = cache->c_ops->co_obj_ops;
770 if (!ops->oo_dump[type])
773 nl_list_for_each_entry(obj, &cache->c_items, ce_list) {
774 if (filter && !nl_object_match_filter(obj, filter))
777 NL_DBG(4, "Dumping object %p...\n", obj);
778 dump_from_ops(obj, params);
790 * Call a callback on each element of the cache.
791 * @arg cache cache to iterate on
792 * @arg cb callback function
793 * @arg arg argument passed to callback function
795 * Calls a callback function \a cb on each element of the \a cache.
796 * The argument \a arg is passed on the callback function.
798 void nl_cache_foreach(struct nl_cache *cache,
799 void (*cb)(struct nl_object *, void *), void *arg)
801 nl_cache_foreach_filter(cache, NULL, cb, arg);
805 * Call a callback on each element of the cache (filtered).
806 * @arg cache cache to iterate on
807 * @arg filter filter object
808 * @arg cb callback function
809 * @arg arg argument passed to callback function
811 * Calls a callback function \a cb on each element of the \a cache
812 * that matches the \a filter. The argument \a arg is passed on
813 * to the callback function.
815 void nl_cache_foreach_filter(struct nl_cache *cache, struct nl_object *filter,
816 void (*cb)(struct nl_object *, void *), void *arg)
818 struct nl_object *obj, *tmp;
819 struct nl_object_ops *ops;
821 if (cache->c_ops == NULL)
824 ops = cache->c_ops->co_obj_ops;
826 nl_list_for_each_entry_safe(obj, tmp, &cache->c_items, ce_list) {
827 if (filter && !nl_object_match_filter(obj, filter))