+/*
+ * lib/cache_mngt.c Cache Management
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation version 2.1
+ * of the License.
+ *
+ * Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
+ */
+
+/**
+ * @ingroup core
+ * @defgroup cache_mngt Caching
+ * @{
+ */
+
+#include <netlink-local.h>
+#include <netlink/netlink.h>
+#include <netlink/cache.h>
+#include <netlink/utils.h>
+
+static struct nl_cache_ops *cache_ops;
+
+/**
+ * @name Cache Operations Sets
+ * @{
+ */
+
+/**
+ * Lookup the set cache operations of a certain cache type
+ * @arg name name of the cache type
+ *
+ * @return The cache operations or NULL if no operations
+ * have been registered under the specified name.
+ */
+struct nl_cache_ops *nl_cache_ops_lookup(const char *name)
+{
+ struct nl_cache_ops *ops;
+
+ for (ops = cache_ops; ops; ops = ops->co_next)
+ if (!strcmp(ops->co_name, name))
+ return ops;
+
+ return NULL;
+}
+
+/**
+ * Associate a message type to a set of cache operations
+ * @arg protocol netlink protocol
+ * @arg msgtype netlink message type
+ *
+ * Associates the specified netlink message type with
+ * a registered set of cache operations.
+ *
+ * @return The cache operations or NULL if no association
+ * could be made.
+ */
+struct nl_cache_ops *nl_cache_ops_associate(int protocol, int msgtype)
+{
+ int i;
+ struct nl_cache_ops *ops;
+
+ for (ops = cache_ops; ops; ops = ops->co_next) {
+ if (ops->co_protocol != protocol)
+ continue;
+
+ for (i = 0; ops->co_msgtypes[i].mt_id >= 0; i++)
+ if (ops->co_msgtypes[i].mt_id == msgtype)
+ return ops;
+ }
+
+ return NULL;
+}
+
+/**
+ * Lookup message type cache association
+ * @arg ops cache operations
+ * @arg msgtype netlink message type
+ *
+ * Searches for a matching message type association ing the specified
+ * cache operations.
+ *
+ * @return A message type association or NULL.
+ */
+struct nl_msgtype *nl_msgtype_lookup(struct nl_cache_ops *ops, int msgtype)
+{
+ int i;
+
+ for (i = 0; ops->co_msgtypes[i].mt_id >= 0; i++)
+ if (ops->co_msgtypes[i].mt_id == msgtype)
+ return &ops->co_msgtypes[i];
+
+ return NULL;
+}
+
+static struct nl_cache_ops *cache_ops_lookup_for_obj(struct nl_object_ops *obj_ops)
+{
+ struct nl_cache_ops *ops;
+
+ for (ops = cache_ops; ops; ops = ops->co_next)
+ if (ops->co_obj_ops == obj_ops)
+ return ops;
+
+ return NULL;
+
+}
+
+/**
+ * Call a function for each registered cache operation
+ * @arg cb Callback function to be called
+ * @arg arg User specific argument.
+ */
+void nl_cache_ops_foreach(void (*cb)(struct nl_cache_ops *, void *), void *arg)
+{
+ struct nl_cache_ops *ops;
+
+ for (ops = cache_ops; ops; ops = ops->co_next)
+ cb(ops, arg);
+}
+
+/**
+ * Register a set of cache operations
+ * @arg ops cache operations
+ *
+ * Called by users of caches to announce the avaibility of
+ * a certain cache type.
+ *
+ * @return 0 on success or a negative error code.
+ */
+int nl_cache_mngt_register(struct nl_cache_ops *ops)
+{
+ if (!ops->co_name || !ops->co_obj_ops)
+ return -NLE_INVAL;
+
+ if (nl_cache_ops_lookup(ops->co_name))
+ return -NLE_EXIST;
+
+ ops->co_next = cache_ops;
+ cache_ops = ops;
+
+ NL_DBG(1, "Registered cache operations %s\n", ops->co_name);
+
+ return 0;
+}
+
+/**
+ * Unregister a set of cache operations
+ * @arg ops cache operations
+ *
+ * Called by users of caches to announce a set of
+ * cache operations is no longer available. The
+ * specified cache operations must have been registered
+ * previously using nl_cache_mngt_register()
+ *
+ * @return 0 on success or a negative error code
+ */
+int nl_cache_mngt_unregister(struct nl_cache_ops *ops)
+{
+ struct nl_cache_ops *t, **tp;
+
+ for (tp = &cache_ops; (t=*tp) != NULL; tp = &t->co_next)
+ if (t == ops)
+ break;
+
+ if (!t)
+ return -NLE_NOCACHE;
+
+ NL_DBG(1, "Unregistered cache operations %s\n", ops->co_name);
+
+ *tp = t->co_next;
+ return 0;
+}
+
+/** @} */
+
+/**
+ * @name Global Cache Provisioning/Requiring
+ * @{
+ */
+
+/**
+ * Provide a cache for global use
+ * @arg cache cache to provide
+ *
+ * Offers the specified cache to be used by other modules.
+ * Only one cache per type may be shared at a time,
+ * a previsouly provided caches will be overwritten.
+ */
+void nl_cache_mngt_provide(struct nl_cache *cache)
+{
+ struct nl_cache_ops *ops;
+
+ ops = cache_ops_lookup_for_obj(cache->c_ops->co_obj_ops);
+ if (!ops)
+ BUG();
+ else
+ ops->co_major_cache = cache;
+}
+
+/**
+ * Unprovide a cache for global use
+ * @arg cache cache to unprovide
+ *
+ * Cancels the offer to use a cache globally. The
+ * cache will no longer be returned via lookups but
+ * may still be in use.
+ */
+void nl_cache_mngt_unprovide(struct nl_cache *cache)
+{
+ struct nl_cache_ops *ops;
+
+ ops = cache_ops_lookup_for_obj(cache->c_ops->co_obj_ops);
+ if (!ops)
+ BUG();
+ else if (ops->co_major_cache == cache)
+ ops->co_major_cache = NULL;
+}
+
+/**
+ * Demand the use of a global cache
+ * @arg name name of the required object type
+ *
+ * Trys to find a cache of the specified type for global
+ * use.
+ *
+ * @return A cache provided by another subsystem of the
+ * specified type marked to be available.
+ */
+struct nl_cache *nl_cache_mngt_require(const char *name)
+{
+ struct nl_cache_ops *ops;
+
+ ops = nl_cache_ops_lookup(name);
+ if (!ops || !ops->co_major_cache) {
+ fprintf(stderr, "Application BUG: Your application must "
+ "call nl_cache_mngt_provide() and\nprovide a valid "
+ "%s cache to be used for internal lookups.\nSee the "
+ " API documentation for more details.\n", name);
+
+ return NULL;
+ }
+
+ return ops->co_major_cache;
+}
+
+/** @} */
+
+/** @} */
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