OpenWrt – Rev 4
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/*
* lib/cache.c Caching Module
*
* 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 cache_mngt
* @defgroup cache Cache
*
* @code
* Cache Management | | Type Specific Cache Operations
*
* | | +----------------+ +------------+
* | request update | | msg_parser |
* | | +----------------+ +------------+
* +- - - - -^- - - - - - - -^- -|- - - -
* nl_cache_update: | | | |
* 1) --------- co_request_update ------+ | |
* | | |
* 2) destroy old cache +----------- pp_cb ---------|---+
* | | |
* 3) ---------- nl_recvmsgs ----------+ +- cb_valid -+
* +--------------+ | | | |
* | nl_cache_add |<-----+ + - - -v- -|- - - - - - - - - - -
* +--------------+ | | +-------------+
* | nl_recvmsgs |
* | | +-----|-^-----+
* +---v-|---+
* | | | nl_recv |
* +---------+
* | | Core Netlink
* @endcode
*
* @{
*/
#include <netlink-local.h>
#include <netlink/netlink.h>
#include <netlink/cache.h>
#include <netlink/object.h>
#include <netlink/utils.h>
/**
* @name Cache Creation/Deletion
* @{
*/
/**
* Allocate an empty cache
* @arg ops cache operations to base the cache on
*
* @return A newly allocated and initialized cache.
*/
struct nl_cache *nl_cache_alloc(struct nl_cache_ops *ops)
{
struct nl_cache *cache;
cache = calloc(1, sizeof(*cache));
if (!cache)
return NULL;
nl_init_list_head(&cache->c_items);
cache->c_ops = ops;
NL_DBG(2, "Allocated cache %p <%s>.\n", cache, nl_cache_name(cache));
return cache;
}
int nl_cache_alloc_and_fill(struct nl_cache_ops *ops, struct nl_sock *sock,
struct nl_cache **result)
{
struct nl_cache *cache;
int err;
if (!(cache = nl_cache_alloc(ops)))
return -NLE_NOMEM;
if (sock && (err = nl_cache_refill(sock, cache)) < 0) {
nl_cache_free(cache);
return err;
}
*result = cache;
return 0;
}
/**
* Clear a cache.
* @arg cache cache to clear
*
* Removes all elements of a cache.
*/
void nl_cache_clear(struct nl_cache *cache)
{
struct nl_object *obj, *tmp;
NL_DBG(1, "Clearing cache %p <%s>...\n", cache, nl_cache_name(cache));
nl_list_for_each_entry_safe(obj, tmp, &cache->c_items, ce_list)
nl_cache_remove(obj);
}
/**
* Free a cache.
* @arg cache Cache to free.
*
* Removes all elements of a cache and frees all memory.
*
* @note Use this function if you are working with allocated caches.
*/
void nl_cache_free(struct nl_cache *cache)
{
if (!cache)
return;
nl_cache_clear(cache);
NL_DBG(1, "Freeing cache %p <%s>...\n", cache, nl_cache_name(cache));
free(cache);
}
/** @} */
/**
* @name Cache Modifications
* @{
*/
static int __cache_add(struct nl_cache *cache, struct nl_object *obj)
{
obj->ce_cache = cache;
nl_list_add_tail(&obj->ce_list, &cache->c_items);
cache->c_nitems++;
NL_DBG(1, "Added %p to cache %p <%s>.\n",
obj, cache, nl_cache_name(cache));
return 0;
}
/**
* Add object to a cache.
* @arg cache Cache to add object to
* @arg obj Object to be added to the cache
*
* Adds the given object to the specified cache. The object is cloned
* if it has been added to another cache already.
*
* @return 0 or a negative error code.
*/
int nl_cache_add(struct nl_cache *cache, struct nl_object *obj)
{
struct nl_object *new;
if (cache->c_ops->co_obj_ops != obj->ce_ops)
return -NLE_OBJ_MISMATCH;
if (!nl_list_empty(&obj->ce_list)) {
new = nl_object_clone(obj);
if (!new)
return -NLE_NOMEM;
} else {
nl_object_get(obj);
new = obj;
}
return __cache_add(cache, new);
}
/**
* Removes an object from a cache.
* @arg obj Object to remove from its cache
*
* Removes the object \c obj from the cache it is assigned to, since
* an object can only be assigned to one cache at a time, the cache
* must ne be passed along with it.
*/
void nl_cache_remove(struct nl_object *obj)
{
struct nl_cache *cache = obj->ce_cache;
if (cache == NULL)
return;
nl_list_del(&obj->ce_list);
obj->ce_cache = NULL;
nl_object_put(obj);
cache->c_nitems--;
NL_DBG(1, "Deleted %p from cache %p <%s>.\n",
obj, cache, nl_cache_name(cache));
}
/** @} */
/**
* @name Synchronization
* @{
*/
/**
* Request a full dump from the kernel to fill a cache
* @arg sk Netlink socket.
* @arg cache Cache subjected to be filled.
*
* Send a dumping request to the kernel causing it to dump all objects
* related to the specified cache to the netlink socket.
*
* Use nl_cache_pickup() to read the objects from the socket and fill them
* into a cache.
*/
int nl_cache_request_full_dump(struct nl_sock *sk, struct nl_cache *cache)
{
NL_DBG(2, "Requesting dump from kernel for cache %p <%s>...\n",
cache, nl_cache_name(cache));
if (cache->c_ops->co_request_update == NULL)
return -NLE_OPNOTSUPP;
return cache->c_ops->co_request_update(cache, sk);
}
/** @cond SKIP */
struct update_xdata {
struct nl_cache_ops *ops;
struct nl_parser_param *params;
};
static int update_msg_parser(struct nl_msg *msg, void *arg)
{
struct update_xdata *x = arg;
return nl_cache_parse(x->ops, &msg->nm_src, msg->nm_nlh, x->params);
}
/** @endcond */
int __cache_pickup(struct nl_sock *sk, struct nl_cache *cache,
struct nl_parser_param *param)
{
int err;
struct nl_cb *cb;
struct update_xdata x = {
.ops = cache->c_ops,
.params = param,
};
NL_DBG(1, "Picking up answer for cache %p <%s>...\n",
cache, nl_cache_name(cache));
cb = nl_cb_clone(sk->s_cb);
if (cb == NULL)
return -NLE_NOMEM;
nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, update_msg_parser, &x);
err = nl_recvmsgs(sk, cb);
if (err < 0)
NL_DBG(2, "While picking up for %p <%s>, recvmsgs() returned " \
"%d: %s", cache, nl_cache_name(cache),
err, nl_geterror(err));
nl_cb_put(cb);
return err;
}
static int pickup_cb(struct nl_object *c, struct nl_parser_param *p)
{
return nl_cache_add((struct nl_cache *) p->pp_arg, c);
}
/**
* Pickup a netlink dump response and put it into a cache.
* @arg sk Netlink socket.
* @arg cache Cache to put items into.
*
* Waits for netlink messages to arrive, parses them and puts them into
* the specified cache.
*
* @return 0 on success or a negative error code.
*/
int nl_cache_pickup(struct nl_sock *sk, struct nl_cache *cache)
{
struct nl_parser_param p = {
.pp_cb = pickup_cb,
.pp_arg = cache,
};
return __cache_pickup(sk, cache, &p);
}
/** @} */
/**
* @name Parsing
* @{
*/
/** @cond SKIP */
int nl_cache_parse(struct nl_cache_ops *ops, struct sockaddr_nl *who,
struct nlmsghdr *nlh, struct nl_parser_param *params)
{
int i, err;
if (!nlmsg_valid_hdr(nlh, ops->co_hdrsize))
return -NLE_MSG_TOOSHORT;
for (i = 0; ops->co_msgtypes[i].mt_id >= 0; i++) {
if (ops->co_msgtypes[i].mt_id == nlh->nlmsg_type) {
err = ops->co_msg_parser(ops, who, nlh, params);
if (err != -NLE_OPNOTSUPP)
goto errout;
}
}
err = -NLE_MSGTYPE_NOSUPPORT;
errout:
return err;
}
/** @endcond */
/**
* Parse a netlink message and add it to the cache.
* @arg cache cache to add element to
* @arg msg netlink message
*
* Parses a netlink message by calling the cache specific message parser
* and adds the new element to the cache.
*
* @return 0 or a negative error code.
*/
int nl_cache_parse_and_add(struct nl_cache *cache, struct nl_msg *msg)
{
struct nl_parser_param p = {
.pp_cb = pickup_cb,
.pp_arg = cache,
};
return nl_cache_parse(cache->c_ops, NULL, nlmsg_hdr(msg), &p);
}
/**
* (Re)fill a cache with the contents in the kernel.
* @arg sk Netlink socket.
* @arg cache cache to update
*
* Clears the specified cache and fills it with the current state in
* the kernel.
*
* @return 0 or a negative error code.
*/
int nl_cache_refill(struct nl_sock *sk, struct nl_cache *cache)
{
int err;
err = nl_cache_request_full_dump(sk, cache);
if (err < 0)
return err;
NL_DBG(2, "Upading cache %p <%s>, request sent, waiting for dump...\n",
cache, nl_cache_name(cache));
nl_cache_clear(cache);
return nl_cache_pickup(sk, cache);
}
/** @} */