2 * lib/cache_mngt.c Cache Management
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_mngt Caching
18 #include <netlink-local.h>
19 #include <netlink/netlink.h>
20 #include <netlink/cache.h>
21 #include <netlink/utils.h>
23 static struct nl_cache_ops *cache_ops;
26 * @name Cache Operations Sets
31 * Lookup the set cache operations of a certain cache type
32 * @arg name name of the cache type
34 * @return The cache operations or NULL if no operations
35 * have been registered under the specified name.
37 struct nl_cache_ops *nl_cache_ops_lookup(const char *name)
39 struct nl_cache_ops *ops;
41 for (ops = cache_ops; ops; ops = ops->co_next)
42 if (!strcmp(ops->co_name, name))
49 * Associate a message type to a set of cache operations
50 * @arg protocol netlink protocol
51 * @arg msgtype netlink message type
53 * Associates the specified netlink message type with
54 * a registered set of cache operations.
56 * @return The cache operations or NULL if no association
59 struct nl_cache_ops *nl_cache_ops_associate(int protocol, int msgtype)
62 struct nl_cache_ops *ops;
64 for (ops = cache_ops; ops; ops = ops->co_next) {
65 if (ops->co_protocol != protocol)
68 for (i = 0; ops->co_msgtypes[i].mt_id >= 0; i++)
69 if (ops->co_msgtypes[i].mt_id == msgtype)
79 * Lookup message type cache association
80 * @arg ops cache operations
81 * @arg msgtype netlink message type
83 * Searches for a matching message type association ing the specified
86 * @return A message type association or NULL.
88 struct nl_msgtype *nl_msgtype_lookup(struct nl_cache_ops *ops, int msgtype)
92 for (i = 0; ops->co_msgtypes[i].mt_id >= 0; i++)
93 if (ops->co_msgtypes[i].mt_id == msgtype)
94 return &ops->co_msgtypes[i];
99 static struct nl_cache_ops *cache_ops_lookup_for_obj(struct nl_object_ops *obj_ops)
101 struct nl_cache_ops *ops;
103 for (ops = cache_ops; ops; ops = ops->co_next)
104 if (ops->co_obj_ops == obj_ops)
112 * Call a function for each registered cache operation
113 * @arg cb Callback function to be called
114 * @arg arg User specific argument.
116 void nl_cache_ops_foreach(void (*cb)(struct nl_cache_ops *, void *), void *arg)
118 struct nl_cache_ops *ops;
120 for (ops = cache_ops; ops; ops = ops->co_next)
126 * Register a set of cache operations
127 * @arg ops cache operations
129 * Called by users of caches to announce the avaibility of
130 * a certain cache type.
132 * @return 0 on success or a negative error code.
134 int nl_cache_mngt_register(struct nl_cache_ops *ops)
136 if (!ops->co_name || !ops->co_obj_ops)
139 if (nl_cache_ops_lookup(ops->co_name))
142 ops->co_next = cache_ops;
145 NL_DBG(1, "Registered cache operations %s\n", ops->co_name);
151 * Unregister a set of cache operations
152 * @arg ops cache operations
154 * Called by users of caches to announce a set of
155 * cache operations is no longer available. The
156 * specified cache operations must have been registered
157 * previously using nl_cache_mngt_register()
159 * @return 0 on success or a negative error code
161 int nl_cache_mngt_unregister(struct nl_cache_ops *ops)
163 struct nl_cache_ops *t, **tp;
165 for (tp = &cache_ops; (t=*tp) != NULL; tp = &t->co_next)
172 NL_DBG(1, "Unregistered cache operations %s\n", ops->co_name);
181 * @name Global Cache Provisioning/Requiring
186 * Provide a cache for global use
187 * @arg cache cache to provide
189 * Offers the specified cache to be used by other modules.
190 * Only one cache per type may be shared at a time,
191 * a previsouly provided caches will be overwritten.
193 void nl_cache_mngt_provide(struct nl_cache *cache)
195 struct nl_cache_ops *ops;
197 ops = cache_ops_lookup_for_obj(cache->c_ops->co_obj_ops);
201 ops->co_major_cache = cache;
205 * Unprovide a cache for global use
206 * @arg cache cache to unprovide
208 * Cancels the offer to use a cache globally. The
209 * cache will no longer be returned via lookups but
210 * may still be in use.
212 void nl_cache_mngt_unprovide(struct nl_cache *cache)
214 struct nl_cache_ops *ops;
216 ops = cache_ops_lookup_for_obj(cache->c_ops->co_obj_ops);
219 else if (ops->co_major_cache == cache)
220 ops->co_major_cache = NULL;
224 * Demand the use of a global cache
225 * @arg name name of the required object type
227 * Trys to find a cache of the specified type for global
230 * @return A cache provided by another subsystem of the
231 * specified type marked to be available.
233 struct nl_cache *nl_cache_mngt_require(const char *name)
235 struct nl_cache_ops *ops;
237 ops = nl_cache_ops_lookup(name);
238 if (!ops || !ops->co_major_cache) {
239 fprintf(stderr, "Application BUG: Your application must "
240 "call nl_cache_mngt_provide() and\nprovide a valid "
241 "%s cache to be used for internal lookups.\nSee the "
242 " API documentation for more details.\n", name);
247 return ops->co_major_cache;