1 files changed, 266 insertions, 0 deletions
diff --git a/lib/cache_mngt.c b/lib/cache_mngt.c
new file mode 100644
index 0000000..7cf1a03
--- /dev/null
+++ b/lib/cache_mngt.c
@@ -0,0 +1,266 @@
+/*
+ * 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) 2003-2006 Thomas Graf <tgraf@suug.ch>
+ */
+
+/**
+ * @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;
+
+/**
+ * Associate a message type to a set of cache operations
+ * @arg protocol		netlink protocol
+ * @arg message_type		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_mngt_associate(int protocol, int message_type)
+{
+	int i;
+	struct nl_cache_ops *ops;
+
+	for (ops = cache_ops; ops; ops = ops->co_next)
+		for (i = 0; ops->co_msgtypes[i].mt_id >= 0; i++)
+			if (ops->co_msgtypes[i].mt_id == message_type &&
+			    ops->co_protocol == protocol)
+				return ops;
+
+	return NULL;
+}
+
+/**
+ * Convert message type to character string.
+ * @arg ops		Cache operations.
+ * @arg protocol	Netlink Protocol.
+ * @arg msgtype		Message type.
+ * @arg buf		Destination buffer.
+ * @arg len		Size of destination buffer.
+ *
+ * Converts a message type to a character string and stores it in the
+ * provided buffer.
+ *
+ * @return The destination buffer or the message type encoded in
+ *         hexidecimal form if no match was found.
+ */
+char *nl_cache_mngt_type2name(struct nl_cache_ops *ops, int protocol,
+			      int msgtype, char *buf, size_t len)
+{
+	int i;
+
+	for (i = 0; ops->co_msgtypes[i].mt_id >= 0; i++) {
+		if (ops->co_msgtypes[i].mt_id == msgtype &&
+		    ops->co_protocol == protocol) {
+			snprintf(buf, len, "%s::%s",
+				 ops->co_name,
+				 ops->co_msgtypes[i].mt_name);
+			return buf;
+		}
+	}
+
+	snprintf(buf, len, "%d:%s->0x%x()", protocol, ops->co_name, msgtype);
+	return buf;
+}
+
+/**
+ * @name Cache Type Management
+ * @{
+ */
+
+/**
+ * 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;
+}
+
+/**
+ * Lookupt the set of cache operations responsible for a type of object
+ * @arg obj_ops		Object operations
+ *
+ * @return The cache operations or NULL if not found.
+ */
+struct nl_cache_ops *nl_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_mngt_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)
+		return nl_error(EINVAL, "No cache name specified");
+
+	if (!ops->co_obj_ops)
+		return nl_error(EINVAL, "No obj cache ops specified");
+
+	if (nl_cache_ops_lookup(ops->co_name))
+		return nl_error(EEXIST, "Cache operations already 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 nl_error(ENOENT, "No such cache operations");
+
+	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 = nl_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 = nl_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;
+}
+
+/** @} */
+
+/** @} */