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 Cache Creation/Deletion
55 * Allocate an empty cache
56 * @arg ops cache operations to base the cache on
58 * @return A newly allocated and initialized cache.
60 struct nl_cache
*nl_cache_alloc(struct nl_cache_ops
*ops
)
62 struct nl_cache
*cache
;
64 cache
= calloc(1, sizeof(*cache
));
68 nl_init_list_head(&cache
->c_items
);
71 NL_DBG(2, "Allocated cache %p <%s>.\n", cache
, nl_cache_name(cache
));
76 int nl_cache_alloc_and_fill(struct nl_cache_ops
*ops
, struct nl_sock
*sock
,
77 struct nl_cache
**result
)
79 struct nl_cache
*cache
;
82 if (!(cache
= nl_cache_alloc(ops
)))
85 if (sock
&& (err
= nl_cache_refill(sock
, cache
)) < 0) {
96 * @arg cache cache to clear
98 * Removes all elements of a cache.
100 void nl_cache_clear(struct nl_cache
*cache
)
102 struct nl_object
*obj
, *tmp
;
104 NL_DBG(1, "Clearing cache %p <%s>...\n", cache
, nl_cache_name(cache
));
106 nl_list_for_each_entry_safe(obj
, tmp
, &cache
->c_items
, ce_list
)
107 nl_cache_remove(obj
);
112 * @arg cache Cache to free.
114 * Removes all elements of a cache and frees all memory.
116 * @note Use this function if you are working with allocated caches.
118 void nl_cache_free(struct nl_cache
*cache
)
123 nl_cache_clear(cache
);
124 NL_DBG(1, "Freeing cache %p <%s>...\n", cache
, nl_cache_name(cache
));
131 * @name Cache Modifications
135 static int __cache_add(struct nl_cache
*cache
, struct nl_object
*obj
)
137 obj
->ce_cache
= cache
;
139 nl_list_add_tail(&obj
->ce_list
, &cache
->c_items
);
142 NL_DBG(1, "Added %p to cache %p <%s>.\n",
143 obj
, cache
, nl_cache_name(cache
));
149 * Add object to a cache.
150 * @arg cache Cache to add object to
151 * @arg obj Object to be added to the cache
153 * Adds the given object to the specified cache. The object is cloned
154 * if it has been added to another cache already.
156 * @return 0 or a negative error code.
158 int nl_cache_add(struct nl_cache
*cache
, struct nl_object
*obj
)
160 struct nl_object
*new;
162 if (cache
->c_ops
->co_obj_ops
!= obj
->ce_ops
)
163 return -NLE_OBJ_MISMATCH
;
165 if (!nl_list_empty(&obj
->ce_list
)) {
166 new = nl_object_clone(obj
);
174 return __cache_add(cache
, new);
178 * Removes an object from a cache.
179 * @arg obj Object to remove from its cache
181 * Removes the object \c obj from the cache it is assigned to, since
182 * an object can only be assigned to one cache at a time, the cache
183 * must ne be passed along with it.
185 void nl_cache_remove(struct nl_object
*obj
)
187 struct nl_cache
*cache
= obj
->ce_cache
;
192 nl_list_del(&obj
->ce_list
);
193 obj
->ce_cache
= NULL
;
197 NL_DBG(1, "Deleted %p from cache %p <%s>.\n",
198 obj
, cache
, nl_cache_name(cache
));
204 * @name Synchronization
209 * Request a full dump from the kernel to fill a cache
210 * @arg sk Netlink socket.
211 * @arg cache Cache subjected to be filled.
213 * Send a dumping request to the kernel causing it to dump all objects
214 * related to the specified cache to the netlink socket.
216 * Use nl_cache_pickup() to read the objects from the socket and fill them
219 int nl_cache_request_full_dump(struct nl_sock
*sk
, struct nl_cache
*cache
)
221 NL_DBG(2, "Requesting dump from kernel for cache %p <%s>...\n",
222 cache
, nl_cache_name(cache
));
224 if (cache
->c_ops
->co_request_update
== NULL
)
225 return -NLE_OPNOTSUPP
;
227 return cache
->c_ops
->co_request_update(cache
, sk
);
231 struct update_xdata
{
232 struct nl_cache_ops
*ops
;
233 struct nl_parser_param
*params
;
236 static int update_msg_parser(struct nl_msg
*msg
, void *arg
)
238 struct update_xdata
*x
= arg
;
240 return nl_cache_parse(x
->ops
, &msg
->nm_src
, msg
->nm_nlh
, x
->params
);
244 int __cache_pickup(struct nl_sock
*sk
, struct nl_cache
*cache
,
245 struct nl_parser_param
*param
)
249 struct update_xdata x
= {
254 NL_DBG(1, "Picking up answer for cache %p <%s>...\n",
255 cache
, nl_cache_name(cache
));
257 cb
= nl_cb_clone(sk
->s_cb
);
261 nl_cb_set(cb
, NL_CB_VALID
, NL_CB_CUSTOM
, update_msg_parser
, &x
);
263 err
= nl_recvmsgs(sk
, cb
);
265 NL_DBG(2, "While picking up for %p <%s>, recvmsgs() returned " \
266 "%d: %s", cache
, nl_cache_name(cache
),
267 err
, nl_geterror(err
));
274 static int pickup_cb(struct nl_object
*c
, struct nl_parser_param
*p
)
276 return nl_cache_add((struct nl_cache
*) p
->pp_arg
, c
);
280 * Pickup a netlink dump response and put it into a cache.
281 * @arg sk Netlink socket.
282 * @arg cache Cache to put items into.
284 * Waits for netlink messages to arrive, parses them and puts them into
285 * the specified cache.
287 * @return 0 on success or a negative error code.
289 int nl_cache_pickup(struct nl_sock
*sk
, struct nl_cache
*cache
)
291 struct nl_parser_param p
= {
296 return __cache_pickup(sk
, cache
, &p
);
308 int nl_cache_parse(struct nl_cache_ops
*ops
, struct sockaddr_nl
*who
,
309 struct nlmsghdr
*nlh
, struct nl_parser_param
*params
)
313 if (!nlmsg_valid_hdr(nlh
, ops
->co_hdrsize
))
314 return -NLE_MSG_TOOSHORT
;
316 for (i
= 0; ops
->co_msgtypes
[i
].mt_id
>= 0; i
++) {
317 if (ops
->co_msgtypes
[i
].mt_id
== nlh
->nlmsg_type
) {
318 err
= ops
->co_msg_parser(ops
, who
, nlh
, params
);
319 if (err
!= -NLE_OPNOTSUPP
)
325 err
= -NLE_MSGTYPE_NOSUPPORT
;
332 * Parse a netlink message and add it to the cache.
333 * @arg cache cache to add element to
334 * @arg msg netlink message
336 * Parses a netlink message by calling the cache specific message parser
337 * and adds the new element to the cache.
339 * @return 0 or a negative error code.
341 int nl_cache_parse_and_add(struct nl_cache
*cache
, struct nl_msg
*msg
)
343 struct nl_parser_param p
= {
348 return nl_cache_parse(cache
->c_ops
, NULL
, nlmsg_hdr(msg
), &p
);
352 * (Re)fill a cache with the contents in the kernel.
353 * @arg sk Netlink socket.
354 * @arg cache cache to update
356 * Clears the specified cache and fills it with the current state in
359 * @return 0 or a negative error code.
361 int nl_cache_refill(struct nl_sock
*sk
, struct nl_cache
*cache
)
365 err
= nl_cache_request_full_dump(sk
, cache
);
369 NL_DBG(2, "Upading cache %p <%s>, request sent, waiting for dump...\n",
370 cache
, nl_cache_name(cache
));
371 nl_cache_clear(cache
);
373 return nl_cache_pickup(sk
, cache
);