nexmon – Rev 1
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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 Access Functions
* @{
*/
/**
* Return the number of items in the cache
* @arg cache cache handle
*/
int nl_cache_nitems(struct nl_cache *cache)
{
return cache->c_nitems;
}
/**
* Return the number of items matching a filter in the cache
* @arg cache Cache object.
* @arg filter Filter object.
*/
int nl_cache_nitems_filter(struct nl_cache *cache, struct nl_object *filter)
{
struct nl_object_ops *ops;
struct nl_object *obj;
int nitems = 0;
if (cache->c_ops == NULL)
BUG();
ops = cache->c_ops->co_obj_ops;
nl_list_for_each_entry(obj, &cache->c_items, ce_list) {
if (filter && !nl_object_match_filter(obj, filter))
continue;
nitems++;
}
return nitems;
}
/**
* Returns \b true if the cache is empty.
* @arg cache Cache to check
* @return \a true if the cache is empty, otherwise \b false is returned.
*/
int nl_cache_is_empty(struct nl_cache *cache)
{
return nl_list_empty(&cache->c_items);
}
/**
* Return the operations set of the cache
* @arg cache cache handle
*/
struct nl_cache_ops *nl_cache_get_ops(struct nl_cache *cache)
{
return cache->c_ops;
}
/**
* Return the first element in the cache
* @arg cache cache handle
*/
struct nl_object *nl_cache_get_first(struct nl_cache *cache)
{
if (nl_list_empty(&cache->c_items))
return NULL;
return nl_list_entry(cache->c_items.next,
struct nl_object, ce_list);
}
/**
* Return the last element in the cache
* @arg cache cache handle
*/
struct nl_object *nl_cache_get_last(struct nl_cache *cache)
{
if (nl_list_empty(&cache->c_items))
return NULL;
return nl_list_entry(cache->c_items.prev,
struct nl_object, ce_list);
}
/**
* Return the next element in the cache
* @arg obj current object
*/
struct nl_object *nl_cache_get_next(struct nl_object *obj)
{
if (nl_list_at_tail(obj, &obj->ce_cache->c_items, ce_list))
return NULL;
else
return nl_list_entry(obj->ce_list.next,
struct nl_object, ce_list);
}
/**
* Return the previous element in the cache
* @arg obj current object
*/
struct nl_object *nl_cache_get_prev(struct nl_object *obj)
{
if (nl_list_at_head(obj, &obj->ce_cache->c_items, ce_list))
return NULL;
else
return nl_list_entry(obj->ce_list.prev,
struct nl_object, ce_list);
}
/** @} */
/**
* @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;
}
/**
* Allocate an empty cache based on type name
* @arg kind Name of cache type
* @return A newly allocated and initialized cache.
*/
int nl_cache_alloc_name(const char *kind, struct nl_cache **result)
{
struct nl_cache_ops *ops;
struct nl_cache *cache;
ops = nl_cache_ops_lookup(kind);
if (!ops)
return -NLE_NOCACHE;
if (!(cache = nl_cache_alloc(ops)))
return -NLE_NOMEM;
*result = cache;
return 0;
}
/**
* Allocate a new cache containing a subset of a cache
* @arg orig Original cache to be based on
* @arg filter Filter defining the subset to be filled into new cache
* @return A newly allocated cache or NULL.
*/
struct nl_cache *nl_cache_subset(struct nl_cache *orig,
struct nl_object *filter)
{
struct nl_cache *cache;
struct nl_object_ops *ops;
struct nl_object *obj;
if (!filter)
BUG();
cache = nl_cache_alloc(orig->c_ops);
if (!cache)
return NULL;
ops = orig->c_ops->co_obj_ops;
nl_list_for_each_entry(obj, &orig->c_items, ce_list) {
if (!nl_object_match_filter(obj, filter))
continue;
nl_cache_add(cache, obj);
}
return cache;
}
/**
* 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);
}
/**
* Move object from one cache to another
* @arg cache Cache to move object to.
* @arg obj Object subject to be moved
*
* Removes the given object from its associated cache if needed
* and adds it to the new cache.
*
* @return 0 on success or a negative error code.
*/
int nl_cache_move(struct nl_cache *cache, struct nl_object *obj)
{
if (cache->c_ops->co_obj_ops != obj->ce_ops)
return -NLE_OBJ_MISMATCH;
NL_DBG(3, "Moving object %p to cache %p\n", obj, cache);
/* Acquire reference, if already in a cache this will be
* reverted during removal */
nl_object_get(obj);
if (!nl_list_empty(&obj->ce_list))
nl_cache_remove(obj);
return __cache_add(cache, obj);
}
/**
* 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));
}
/**
* Search for an object in a cache
* @arg cache Cache to search in.
* @arg needle Object to look for.
*
* Iterates over the cache and looks for an object with identical
* identifiers as the needle.
*
* @return Reference to object or NULL if not found.
* @note The returned object must be returned via nl_object_put().
*/
struct nl_object *nl_cache_search(struct nl_cache *cache,
struct nl_object *needle)
{
struct nl_object *obj;
nl_list_for_each_entry(obj, &cache->c_items, ce_list) {
if (nl_object_identical(obj, needle)) {
nl_object_get(obj);
return obj;
}
}
return NULL;
}
/** @} */
/**
* @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);
}
static int cache_include(struct nl_cache *cache, struct nl_object *obj,
struct nl_msgtype *type, change_func_t cb, void *data)
{
struct nl_object *old;
switch (type->mt_act) {
case NL_ACT_NEW:
case NL_ACT_DEL:
old = nl_cache_search(cache, obj);
if (old) {
nl_cache_remove(old);
if (type->mt_act == NL_ACT_DEL) {
if (cb)
cb(cache, old, NL_ACT_DEL, data);
nl_object_put(old);
}
}
if (type->mt_act == NL_ACT_NEW) {
nl_cache_move(cache, obj);
if (old == NULL && cb)
cb(cache, obj, NL_ACT_NEW, data);
else if (old) {
if (nl_object_diff(old, obj) && cb)
cb(cache, obj, NL_ACT_CHANGE, data);
nl_object_put(old);
}
}
break;
default:
NL_DBG(2, "Unknown action associated to object %p\n", obj);
return 0;
}
return 0;
}
int nl_cache_include(struct nl_cache *cache, struct nl_object *obj,
change_func_t change_cb, void *data)
{
struct nl_cache_ops *ops = cache->c_ops;
int i;
if (ops->co_obj_ops != obj->ce_ops)
return -NLE_OBJ_MISMATCH;
for (i = 0; ops->co_msgtypes[i].mt_id >= 0; i++)
if (ops->co_msgtypes[i].mt_id == obj->ce_msgtype)
return cache_include(cache, obj, &ops->co_msgtypes[i],
change_cb, data);
return -NLE_MSGTYPE_NOSUPPORT;
}
static int resync_cb(struct nl_object *c, struct nl_parser_param *p)
{
struct nl_cache_assoc *ca = p->pp_arg;
return nl_cache_include(ca->ca_cache, c, ca->ca_change, ca->ca_change_data);
}
int nl_cache_resync(struct nl_sock *sk, struct nl_cache *cache,
change_func_t change_cb, void *data)
{
struct nl_object *obj, *next;
struct nl_cache_assoc ca = {
.ca_cache = cache,
.ca_change = change_cb,
.ca_change_data = data,
};
struct nl_parser_param p = {
.pp_cb = resync_cb,
.pp_arg = &ca,
};
int err;
NL_DBG(1, "Resyncing cache %p <%s>...\n", cache, nl_cache_name(cache));
/* Mark all objects so we can see if some of them are obsolete */
nl_cache_mark_all(cache);
err = nl_cache_request_full_dump(sk, cache);
if (err < 0)
goto errout;
err = __cache_pickup(sk, cache, &p);
if (err < 0)
goto errout;
nl_list_for_each_entry_safe(obj, next, &cache->c_items, ce_list) {
if (nl_object_is_marked(obj)) {
nl_object_get(obj);
nl_cache_remove(obj);
if (change_cb)
change_cb(cache, obj, NL_ACT_DEL, data);
nl_object_put(obj);
}
}
NL_DBG(1, "Finished resyncing %p <%s>\n", cache, nl_cache_name(cache));
err = 0;
errout:
return err;
}
/** @} */
/**
* @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);
}
/** @} */
/**
* @name Utillities
* @{
*/
/**
* Mark all objects in a cache
* @arg cache Cache to mark all objects in
*/
void nl_cache_mark_all(struct nl_cache *cache)
{
struct nl_object *obj;
NL_DBG(2, "Marking all objects in cache %p <%s>...\n",
cache, nl_cache_name(cache));
nl_list_for_each_entry(obj, &cache->c_items, ce_list)
nl_object_mark(obj);
}
/** @} */
/**
* @name Dumping
* @{
*/
/**
* Dump all elements of a cache.
* @arg cache cache to dump
* @arg params dumping parameters
*
* Dumps all elements of the \a cache to the file descriptor \a fd.
*/
void nl_cache_dump(struct nl_cache *cache, struct nl_dump_params *params)
{
nl_cache_dump_filter(cache, params, NULL);
}
/**
* Dump all elements of a cache (filtered).
* @arg cache cache to dump
* @arg params dumping parameters (optional)
* @arg filter filter object
*
* Dumps all elements of the \a cache to the file descriptor \a fd
* given they match the given filter \a filter.
*/
void nl_cache_dump_filter(struct nl_cache *cache,
struct nl_dump_params *params,
struct nl_object *filter)
{
int type = params ? params->dp_type : NL_DUMP_DETAILS;
struct nl_object_ops *ops;
struct nl_object *obj;
NL_DBG(2, "Dumping cache %p <%s> filter %p\n",
cache, nl_cache_name(cache), filter);
if (type > NL_DUMP_MAX || type < 0)
BUG();
if (cache->c_ops == NULL)
BUG();
ops = cache->c_ops->co_obj_ops;
if (!ops->oo_dump[type])
return;
nl_list_for_each_entry(obj, &cache->c_items, ce_list) {
if (filter && !nl_object_match_filter(obj, filter))
continue;
NL_DBG(4, "Dumping object %p...\n", obj);
dump_from_ops(obj, params);
}
}
/** @} */
/**
* @name Iterators
* @{
*/
/**
* Call a callback on each element of the cache.
* @arg cache cache to iterate on
* @arg cb callback function
* @arg arg argument passed to callback function
*
* Calls a callback function \a cb on each element of the \a cache.
* The argument \a arg is passed on the callback function.
*/
void nl_cache_foreach(struct nl_cache *cache,
void (*cb)(struct nl_object *, void *), void *arg)
{
nl_cache_foreach_filter(cache, NULL, cb, arg);
}
/**
* Call a callback on each element of the cache (filtered).
* @arg cache cache to iterate on
* @arg filter filter object
* @arg cb callback function
* @arg arg argument passed to callback function
*
* Calls a callback function \a cb on each element of the \a cache
* that matches the \a filter. The argument \a arg is passed on
* to the callback function.
*/
void nl_cache_foreach_filter(struct nl_cache *cache, struct nl_object *filter,
void (*cb)(struct nl_object *, void *), void *arg)
{
struct nl_object *obj, *tmp;
struct nl_object_ops *ops;
if (cache->c_ops == NULL)
BUG();
ops = cache->c_ops->co_obj_ops;
nl_list_for_each_entry_safe(obj, tmp, &cache->c_items, ce_list) {
if (filter && !nl_object_match_filter(obj, filter))
continue;
cb(obj, arg);
}
}
/** @} */
/** @} */