376 lines
8.7 KiB
C
376 lines
8.7 KiB
C
/*
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* lib/cache.c Caching Module
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation version 2.1
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* of the License.
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*
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* Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
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*/
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/**
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* @ingroup cache_mngt
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* @defgroup cache Cache
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*
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* @code
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* Cache Management | | Type Specific Cache Operations
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*
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* | | +----------------+ +------------+
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* | request update | | msg_parser |
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* | | +----------------+ +------------+
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* +- - - - -^- - - - - - - -^- -|- - - -
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* nl_cache_update: | | | |
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* 1) --------- co_request_update ------+ | |
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* | | |
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* 2) destroy old cache +----------- pp_cb ---------|---+
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* | | |
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* 3) ---------- nl_recvmsgs ----------+ +- cb_valid -+
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* +--------------+ | | | |
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* | nl_cache_add |<-----+ + - - -v- -|- - - - - - - - - - -
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* +--------------+ | | +-------------+
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* | nl_recvmsgs |
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* | | +-----|-^-----+
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* +---v-|---+
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* | | | nl_recv |
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* +---------+
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* | | Core Netlink
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* @endcode
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*
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* @{
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*/
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#include <netlink-local.h>
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#include <netlink/netlink.h>
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#include <netlink/cache.h>
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#include <netlink/object.h>
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#include <netlink/utils.h>
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/**
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* @name Cache Creation/Deletion
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* @{
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*/
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/**
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* Allocate an empty cache
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* @arg ops cache operations to base the cache on
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*
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* @return A newly allocated and initialized cache.
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*/
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struct nl_cache *nl_cache_alloc(struct nl_cache_ops *ops)
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{
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struct nl_cache *cache;
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cache = calloc(1, sizeof(*cache));
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if (!cache)
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return NULL;
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nl_init_list_head(&cache->c_items);
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cache->c_ops = ops;
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NL_DBG(2, "Allocated cache %p <%s>.\n", cache, nl_cache_name(cache));
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return cache;
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}
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int nl_cache_alloc_and_fill(struct nl_cache_ops *ops, struct nl_sock *sock,
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struct nl_cache **result)
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{
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struct nl_cache *cache;
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int err;
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if (!(cache = nl_cache_alloc(ops)))
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return -NLE_NOMEM;
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if (sock && (err = nl_cache_refill(sock, cache)) < 0) {
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nl_cache_free(cache);
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return err;
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}
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*result = cache;
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return 0;
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}
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/**
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* Clear a cache.
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* @arg cache cache to clear
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*
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* Removes all elements of a cache.
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*/
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void nl_cache_clear(struct nl_cache *cache)
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{
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struct nl_object *obj, *tmp;
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NL_DBG(1, "Clearing cache %p <%s>...\n", cache, nl_cache_name(cache));
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nl_list_for_each_entry_safe(obj, tmp, &cache->c_items, ce_list)
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nl_cache_remove(obj);
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}
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/**
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* Free a cache.
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* @arg cache Cache to free.
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*
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* Removes all elements of a cache and frees all memory.
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*
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* @note Use this function if you are working with allocated caches.
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*/
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void nl_cache_free(struct nl_cache *cache)
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{
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if (!cache)
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return;
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nl_cache_clear(cache);
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NL_DBG(1, "Freeing cache %p <%s>...\n", cache, nl_cache_name(cache));
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free(cache);
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}
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/** @} */
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/**
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* @name Cache Modifications
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* @{
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*/
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static int __cache_add(struct nl_cache *cache, struct nl_object *obj)
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{
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obj->ce_cache = cache;
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nl_list_add_tail(&obj->ce_list, &cache->c_items);
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cache->c_nitems++;
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NL_DBG(1, "Added %p to cache %p <%s>.\n",
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obj, cache, nl_cache_name(cache));
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return 0;
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}
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/**
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* Add object to a cache.
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* @arg cache Cache to add object to
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* @arg obj Object to be added to the cache
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*
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* Adds the given object to the specified cache. The object is cloned
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* if it has been added to another cache already.
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*
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* @return 0 or a negative error code.
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*/
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int nl_cache_add(struct nl_cache *cache, struct nl_object *obj)
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{
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struct nl_object *new;
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if (cache->c_ops->co_obj_ops != obj->ce_ops)
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return -NLE_OBJ_MISMATCH;
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if (!nl_list_empty(&obj->ce_list)) {
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new = nl_object_clone(obj);
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if (!new)
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return -NLE_NOMEM;
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} else {
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nl_object_get(obj);
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new = obj;
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}
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return __cache_add(cache, new);
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}
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/**
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* Removes an object from a cache.
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* @arg obj Object to remove from its cache
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*
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* Removes the object \c obj from the cache it is assigned to, since
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* an object can only be assigned to one cache at a time, the cache
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* must ne be passed along with it.
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*/
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void nl_cache_remove(struct nl_object *obj)
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{
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struct nl_cache *cache = obj->ce_cache;
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if (cache == NULL)
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return;
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nl_list_del(&obj->ce_list);
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obj->ce_cache = NULL;
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nl_object_put(obj);
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cache->c_nitems--;
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NL_DBG(1, "Deleted %p from cache %p <%s>.\n",
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obj, cache, nl_cache_name(cache));
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}
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/** @} */
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/**
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* @name Synchronization
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* @{
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*/
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/**
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* Request a full dump from the kernel to fill a cache
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* @arg sk Netlink socket.
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* @arg cache Cache subjected to be filled.
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*
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* Send a dumping request to the kernel causing it to dump all objects
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* related to the specified cache to the netlink socket.
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*
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* Use nl_cache_pickup() to read the objects from the socket and fill them
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* into a cache.
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*/
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int nl_cache_request_full_dump(struct nl_sock *sk, struct nl_cache *cache)
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{
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NL_DBG(2, "Requesting dump from kernel for cache %p <%s>...\n",
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cache, nl_cache_name(cache));
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if (cache->c_ops->co_request_update == NULL)
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return -NLE_OPNOTSUPP;
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return cache->c_ops->co_request_update(cache, sk);
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}
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/** @cond SKIP */
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struct update_xdata {
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struct nl_cache_ops *ops;
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struct nl_parser_param *params;
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};
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static int update_msg_parser(struct nl_msg *msg, void *arg)
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{
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struct update_xdata *x = arg;
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return nl_cache_parse(x->ops, &msg->nm_src, msg->nm_nlh, x->params);
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}
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/** @endcond */
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int __cache_pickup(struct nl_sock *sk, struct nl_cache *cache,
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struct nl_parser_param *param)
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{
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int err;
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struct nl_cb *cb;
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struct update_xdata x = {
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.ops = cache->c_ops,
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.params = param,
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};
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NL_DBG(1, "Picking up answer for cache %p <%s>...\n",
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cache, nl_cache_name(cache));
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cb = nl_cb_clone(sk->s_cb);
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if (cb == NULL)
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return -NLE_NOMEM;
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nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, update_msg_parser, &x);
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err = nl_recvmsgs(sk, cb);
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if (err < 0)
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NL_DBG(2, "While picking up for %p <%s>, recvmsgs() returned " \
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"%d: %s", cache, nl_cache_name(cache),
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err, nl_geterror(err));
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nl_cb_put(cb);
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return err;
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}
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static int pickup_cb(struct nl_object *c, struct nl_parser_param *p)
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{
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return nl_cache_add((struct nl_cache *) p->pp_arg, c);
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}
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/**
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* Pickup a netlink dump response and put it into a cache.
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* @arg sk Netlink socket.
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* @arg cache Cache to put items into.
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*
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* Waits for netlink messages to arrive, parses them and puts them into
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* the specified cache.
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*
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* @return 0 on success or a negative error code.
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*/
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int nl_cache_pickup(struct nl_sock *sk, struct nl_cache *cache)
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{
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struct nl_parser_param p = {
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.pp_cb = pickup_cb,
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.pp_arg = cache,
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};
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return __cache_pickup(sk, cache, &p);
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}
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/** @} */
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/**
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* @name Parsing
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* @{
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*/
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/** @cond SKIP */
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int nl_cache_parse(struct nl_cache_ops *ops, struct sockaddr_nl *who,
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struct nlmsghdr *nlh, struct nl_parser_param *params)
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{
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int i, err;
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if (!nlmsg_valid_hdr(nlh, ops->co_hdrsize))
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return -NLE_MSG_TOOSHORT;
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for (i = 0; ops->co_msgtypes[i].mt_id >= 0; i++) {
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if (ops->co_msgtypes[i].mt_id == nlh->nlmsg_type) {
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err = ops->co_msg_parser(ops, who, nlh, params);
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if (err != -NLE_OPNOTSUPP)
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goto errout;
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}
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}
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err = -NLE_MSGTYPE_NOSUPPORT;
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errout:
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return err;
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}
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/** @endcond */
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/**
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* Parse a netlink message and add it to the cache.
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* @arg cache cache to add element to
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* @arg msg netlink message
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*
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* Parses a netlink message by calling the cache specific message parser
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* and adds the new element to the cache.
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*
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* @return 0 or a negative error code.
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*/
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int nl_cache_parse_and_add(struct nl_cache *cache, struct nl_msg *msg)
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{
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struct nl_parser_param p = {
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.pp_cb = pickup_cb,
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.pp_arg = cache,
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};
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return nl_cache_parse(cache->c_ops, NULL, nlmsg_hdr(msg), &p);
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}
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/**
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* (Re)fill a cache with the contents in the kernel.
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* @arg sk Netlink socket.
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* @arg cache cache to update
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*
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* Clears the specified cache and fills it with the current state in
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* the kernel.
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*
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* @return 0 or a negative error code.
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*/
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int nl_cache_refill(struct nl_sock *sk, struct nl_cache *cache)
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{
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int err;
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err = nl_cache_request_full_dump(sk, cache);
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if (err < 0)
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return err;
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NL_DBG(2, "Upading cache %p <%s>, request sent, waiting for dump...\n",
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cache, nl_cache_name(cache));
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nl_cache_clear(cache);
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return nl_cache_pickup(sk, cache);
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}
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/** @} */
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