Macros
#define	NL_CACHE_AF_ITER 0x0001
	Explicitely iterate over all address families when updating the cache.

Access Functions
int	nl_cache_nitems (struct nl_cache *cache)
	Return the number of items in the cache. More...

int	nl_cache_nitems_filter (struct nl_cache cache, struct nl_object filter)
	Return the number of items matching a filter in the cache. More...

int	nl_cache_is_empty (struct nl_cache *cache)
	Returns true if the cache is empty. More...

struct nl_cache_ops *	nl_cache_get_ops (struct nl_cache *cache)
	Return the operations set of the cache. More...

struct nl_object *	nl_cache_get_first (struct nl_cache *cache)
	Return the first element in the cache. More...

struct nl_object *	nl_cache_get_last (struct nl_cache *cache)
	Return the last element in the cache. More...

struct nl_object *	nl_cache_get_next (struct nl_object *obj)
	Return the next element in the cache. More...

struct nl_object *	nl_cache_get_prev (struct nl_object *obj)
	Return the previous element in the cache. More...

Cache Allocation/Deletion
struct nl_cache *	nl_cache_alloc (struct nl_cache_ops *ops)
	Allocate new cache. More...

int	nl_cache_alloc_and_fill (struct nl_cache_ops ops, struct nl_sock sock, struct nl_cache **result)
	Allocate new cache and fill it. More...

int	nl_cache_alloc_name (const char kind, struct nl_cache *result)
	Allocate new cache based on type name. More...

struct nl_cache *	nl_cache_subset (struct nl_cache orig, struct nl_object filter)
	Allocate new cache containing a subset of an existing cache. More...

struct nl_cache *	nl_cache_clone (struct nl_cache *cache)
	Allocate new cache and copy the contents of an existing cache. More...

void	nl_cache_clear (struct nl_cache *cache)
	Remove all objects of a cache. More...

void	nl_cache_get (struct nl_cache *cache)
	Increase reference counter of cache. More...

void	nl_cache_free (struct nl_cache *cache)
	Free a cache. More...

void	nl_cache_put (struct nl_cache *cache)

Cache Modifications
int	nl_cache_add (struct nl_cache cache, struct nl_object obj)
	Add object to cache. More...

int	nl_cache_move (struct nl_cache cache, struct nl_object obj)
	Move object from one cache to another. More...

void	nl_cache_remove (struct nl_object *obj)
	Remove object from cache. More...

Synchronization
void	nl_cache_set_arg1 (struct nl_cache *cache, int arg)
	Set synchronization arg1 of cache. More...

void	nl_cache_set_arg2 (struct nl_cache *cache, int arg)
	Set synchronization arg2 of cache. More...

void	nl_cache_set_flags (struct nl_cache *cache, unsigned int flags)
	Set cache flags. More...

int	nl_cache_pickup (struct nl_sock sk, struct nl_cache cache)
	Pickup a netlink dump response and put it into a cache. More...

int	nl_cache_include (struct nl_cache cache, struct nl_object obj, change_func_t change_cb, void *data)

int	nl_cache_resync (struct nl_sock sk, struct nl_cache cache, change_func_t change_cb, void *data)

Parsing
int	nl_cache_parse_and_add (struct nl_cache cache, struct nl_msg msg)
	Parse a netlink message and add it to the cache. More...

int	nl_cache_refill (struct nl_sock sk, struct nl_cache cache)
	(Re)fill a cache with the contents in the kernel. More...

Utillities
struct nl_object *	nl_cache_search (struct nl_cache cache, struct nl_object needle)
	Search object in cache. More...

struct nl_object *	nl_cache_find (struct nl_cache cache, struct nl_object filter)
	Find object in cache. More...

void	nl_cache_mark_all (struct nl_cache *cache)
	Mark all objects of a cache. More...

Dumping
void	nl_cache_dump (struct nl_cache cache, struct nl_dump_params params)
	Dump all elements of a cache. More...

void	nl_cache_dump_filter (struct nl_cache cache, struct nl_dump_params params, struct nl_object *filter)
	Dump all elements of a cache (filtered). More...

Iterators
void	nl_cache_foreach (struct nl_cache cache, void(cb)(struct nl_object , void ), void *arg)
	Call a callback on each element of the cache. More...

void	nl_cache_foreach_filter (struct nl_cache cache, struct nl_object filter, void(cb)(struct nl_object , void ), void arg)
	Call a callback on each element of the cache (filtered). More...

Detailed Description

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

Related sections in the development guide:

Caching System (Netlink Core Library Development Guide)

Header

#include <netlink/cache.h>

Function Documentation

int nl_cache_nitems ( struct nl_cache * cache )

Return the number of items in the cache.

Parameters

cache cache handle

Definition at line 68 of file cache.c.

Referenced by nl_cache_mngr_info().

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int nl_cache_nitems_filter	(	struct nl_cache *	cache,
		struct nl_object *	filter
	)

Return the number of items matching a filter in the cache.

Parameters

cache	Cache object.
filter	Filter object.

Definition at line 78 of file cache.c.

References nl_object_match_filter().

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int nl_cache_is_empty ( struct nl_cache * cache )

Returns true if the cache is empty.

Parameters

cache Cache to check

Returns: true if the cache is empty, otherwise false is returned.

Definition at line 101 of file cache.c.

struct nl_cache_ops* nl_cache_get_ops ( struct nl_cache * cache )

read

Return the operations set of the cache.

Parameters

cache cache handle

Definition at line 110 of file cache.c.

Referenced by nl_cache_clone().

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struct nl_object* nl_cache_get_first ( struct nl_cache * cache )

read

Return the first element in the cache.

Parameters

cache cache handle

Definition at line 119 of file cache.c.

struct nl_object* nl_cache_get_last ( struct nl_cache * cache )

read

Return the last element in the cache.

Parameters

cache cache handle

Definition at line 132 of file cache.c.

struct nl_object* nl_cache_get_next ( struct nl_object * obj )

read

Return the next element in the cache.

Parameters

obj	current object

Definition at line 145 of file cache.c.

struct nl_object* nl_cache_get_prev ( struct nl_object * obj )

read

Return the previous element in the cache.

Parameters

obj	current object

Definition at line 158 of file cache.c.

struct nl_cache* nl_cache_alloc ( struct nl_cache_ops * ops )

read

Allocate new cache.

Parameters

ops	Cache operations

Allocate and initialize a new cache based on the cache operations provided.

Returns: Allocated cache or NULL if allocation failed.

Definition at line 183 of file cache.c.

References nl_hash_table_alloc().

Referenced by flnl_result_alloc_cache(), idiagnl_msg_alloc_cache(), nl_cache_alloc_and_fill(), nl_cache_alloc_name(), nl_cache_clone(), nl_cache_mngr_add(), nl_cache_subset(), rtnl_class_alloc_cache(), rtnl_cls_alloc_cache(), rtnl_link_alloc_cache(), rtnl_route_alloc_cache(), and rtnl_rule_alloc_cache().

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int nl_cache_alloc_and_fill	(	struct nl_cache_ops *	ops,
		struct nl_sock *	sock,
		struct nl_cache **	result
	)

Allocate new cache and fill it.

Parameters

ops	Cache operations
sock	Netlink socket
result	Result pointer

Allocate new cache and fill it. Equivalent to calling:

cache = nl_cache_alloc(ops);

nl_cache_refill(sock, cache);

See Also: nl_cache_alloc

Returns: 0 on success or a negative error code.

Definition at line 233 of file cache.c.

References nl_cache_alloc(), nl_cache_free(), and nl_cache_refill().

Referenced by genl_ctrl_alloc_cache(), nfnl_ct_alloc_cache(), nfnl_exp_alloc_cache(), rtnl_neigh_alloc_cache(), rtnl_neightbl_alloc_cache(), and rtnl_qdisc_alloc_cache().

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int nl_cache_alloc_name	(	const char *	kind,
		struct nl_cache **	result
	)

Allocate new cache based on type name.

Parameters

kind	Name of cache type
result	Result pointer

Lookup cache ops via nl_cache_ops_lookup() and allocate the cache by calling nl_cache_alloc(). Stores the allocated cache in the result pointer provided.

See Also: nl_cache_alloc

Returns: 0 on success or a negative error code.

Definition at line 264 of file cache.c.

References nl_cache_alloc(), nl_cache_ops_lookup_safe(), and nl_cache_ops_put().

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struct nl_cache* nl_cache_subset	(	struct nl_cache *	orig,
		struct nl_object *	filter
	)

read

Allocate new cache containing a subset of an existing cache.

Parameters

orig	Original cache to base new cache on
filter	Filter defining the subset to be filled into the new cache

Allocates a new cache matching the type of the cache specified by orig. Iterates over the orig cache applying the specified filter and copies all objects that match to the new cache.

The copied objects are clones but do not contain a reference to each other. Later modifications to objects in the original cache will not affect objects in the new cache.

Returns: A newly allocated cache or NULL.

Definition at line 297 of file cache.c.

References nl_cache_add(), nl_cache_alloc(), and nl_object_match_filter().

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struct nl_cache* nl_cache_clone ( struct nl_cache * cache )

read

Allocate new cache and copy the contents of an existing cache.

Parameters

cache Original cache to base new cache on

Allocates a new cache matching the type of the cache specified by cache. Iterates over the cache cache and copies all objects to the new cache.

The copied objects are clones but do not contain a reference to each other. Later modifications to objects in the original cache will not affect objects in the new cache.

Returns: A newly allocated cache or NULL.

Definition at line 337 of file cache.c.

References nl_cache_add(), nl_cache_alloc(), and nl_cache_get_ops().

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void nl_cache_clear ( struct nl_cache * cache )

Remove all objects of a cache.

Parameters

cache Cache to clear

The objects are unliked/removed from the cache by calling nl_cache_remove() on each object in the cache. If any of the objects to not contain any further references to them, those objects will be freed.

Unlike with nl_cache_free(), the cache is not freed just emptied.

Definition at line 366 of file cache.c.

References nl_cache_remove().

Referenced by nl_cache_refill().

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void nl_cache_get ( struct nl_cache * cache )

Increase reference counter of cache.

Parameters

cache Cache

Definition at line 391 of file cache.c.

Referenced by nl_cache_mngt_provide(), and nl_cache_mngt_require_safe().

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void nl_cache_free ( struct nl_cache * cache )

Free a cache.

Parameters

cache Cache to free.

Calls nl_cache_clear() to remove all objects associated with the cache and frees the cache afterwards.

See Also: nl_cache_clear()

Definition at line 408 of file cache.c.

Referenced by genl_mngt_resolve(), genl_ops_resolve(), nl_cache_alloc_and_fill(), nl_cache_mngr_add(), nl_cache_mngr_free(), nl_cache_mngt_unprovide(), rtnl_class_alloc_cache(), rtnl_cls_alloc_cache(), and rtnl_link_alloc_cache().

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int nl_cache_add	(	struct nl_cache *	cache,
		struct nl_object *	obj
	)

Add object to cache.

Parameters

cache	Cache
obj	Object to be added to the cache

Adds the object obj to the specified cache. In case the object is already associated with another cache, the object is cloned before adding it to the cache. In this case, the sole reference to the object will be the one of the cache. Therefore clearing/freeing the cache will result in the object being freed again.

If the object has not been associated with a cache yet, the reference counter of the object is incremented to account for the additional reference.

The type of the object and cache must match, otherwise an error is returned (-NLE_OBJ_MISMATCH).

See Also: nl_cache_move()

Returns: 0 or a negative error code.

Definition at line 479 of file cache.c.

References nl_object_clone(), nl_object_get(), and nl_object_put().

Referenced by nl_cache_clone(), and nl_cache_subset().

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int nl_cache_move	(	struct nl_cache *	cache,
		struct nl_object *	obj
	)

Move object from one cache to another.

Parameters

cache	Cache to move object to.
obj	Object subject to be moved

Removes the the specified object obj from its associated cache and moves it to another cache.

If the object is not associated with a cache, the function behaves just like nl_cache_add().

The type of the object and cache must match, otherwise an error is returned (-NLE_OBJ_MISMATCH).

See Also: nl_cache_add()

Returns: 0 on success or a negative error code.

Definition at line 523 of file cache.c.

References nl_cache_remove(), and nl_object_get().

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void nl_cache_remove ( struct nl_object * obj )

Remove object from cache.

Parameters

obj	Object to remove from cache

Removes the object obj from the cache it is associated with. The reference counter of the object will be decremented. If the reference to the object was the only one remaining, the object will be freed.

If no cache is associated with the object, this function is a NOP.

Definition at line 551 of file cache.c.

References nl_hash_table_del(), and nl_object_put().

Referenced by nl_cache_clear(), nl_cache_move(), and nl_object_free().

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void nl_cache_set_arg1	(	struct nl_cache *	cache,
		int	arg
	)

Set synchronization arg1 of cache.

Parameters

cache	Cache
arg	argument

Synchronization arguments are used to specify filters when requesting dumps from the kernel.

Definition at line 590 of file cache.c.

Referenced by nl_cache_refill().

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void nl_cache_set_arg2	(	struct nl_cache *	cache,
		int	arg
	)

Set synchronization arg2 of cache.

Parameters

cache	Cache
arg	argument

Synchronization arguments are used to specify filters when requesting dumps from the kernel.

Definition at line 603 of file cache.c.

void nl_cache_set_flags	(	struct nl_cache *	cache,
		unsigned int	flags
	)

Set cache flags.

Parameters

cache	Cache
flags	Flags

Definition at line 613 of file cache.c.

int nl_cache_pickup	(	struct nl_sock *	sk,
		struct nl_cache *	cache
	)

Pickup a netlink dump response and put it into a cache.

Parameters

sk	Netlink socket.
cache	Cache to put items into.

Waits for netlink messages to arrive, parses them and puts them into the specified cache. If an old object with same key attributes is present in the cache, it is replaced with the new object. If the old object type supports an update operation, an update is attempted before a replace.

Returns: 0 on success or a negative error code.

Definition at line 743 of file cache.c.

Referenced by flnl_lookup(), and nl_cache_refill().

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int nl_cache_parse_and_add	(	struct nl_cache *	cache,
		struct nl_msg *	msg
	)

Parse a netlink message and add it to the cache.

Parameters

cache	cache to add element to
msg	netlink message

Parses a netlink message by calling the cache specific message parser and adds the new element to the cache. If an old object with same key attributes is present in the cache, it is replaced with the new object. If the old object type supports an update operation, an update is attempted before a replace.

Returns: 0 or a negative error code.

Definition at line 940 of file cache.c.

References nlmsg_hdr().

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int nl_cache_refill	(	struct nl_sock *	sk,
		struct nl_cache *	cache
	)

(Re)fill a cache with the contents in the kernel.

Parameters

sk	Netlink socket.
cache	cache to update

Clears the specified cache and fills it with the current state in the kernel.

Returns: 0 or a negative error code.

Definition at line 960 of file cache.c.

References NL_CACHE_AF_ITER, nl_cache_clear(), nl_cache_pickup(), and nl_cache_set_arg1().

Referenced by idiagnl_msg_alloc_cache(), nl_cache_alloc_and_fill(), nl_cache_mngr_add_cache(), rtnl_class_alloc_cache(), rtnl_cls_alloc_cache(), rtnl_link_alloc_cache(), rtnl_route_alloc_cache(), and rtnl_rule_alloc_cache().

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struct nl_object* nl_cache_search	(	struct nl_cache *	cache,
		struct nl_object *	needle
	)

read

Search object in cache.

Parameters

cache	Cache
needle	Object to look for.

Searches the cache for an object which matches the object needle. The function nl_object_identical() is used to determine if the objects match. If a matching object is found, the reference counter is incremented and the object is returned.

Therefore, if an object is returned, the reference to the object must be returned by calling nl_object_put() after usage.

Returns: Reference to object or NULL if not found.

Definition at line 1033 of file cache.c.

References nl_object_get(), and nl_object_identical().

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struct nl_object* nl_cache_find	(	struct nl_cache *	cache,
		struct nl_object *	filter
	)

read

Find object in cache.

Parameters

cache	Cache
filter	object acting as a filter

Searches the cache for an object which matches the object filter. If the filter attributes matches the object type id attributes, and the cache supports hash lookups, a faster hashtable lookup is used to return the object. Else, function nl_object_match_filter() is used to determine if the objects match. If a matching object is found, the reference counter is incremented and the object is returned.

Therefore, if an object is returned, the reference to the object must be returned by calling nl_object_put() after usage.

Returns: Reference to object or NULL if not found.

Definition at line 1068 of file cache.c.

References nl_object_get(), nl_object_get_id_attrs(), and nl_object_match_filter().

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void nl_cache_mark_all ( struct nl_cache * cache )

Mark all objects of a cache.

Parameters

cache Cache

Marks all objects of a cache by calling nl_object_mark() on each object associated with the cache.

Definition at line 1097 of file cache.c.

References nl_object_mark().

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void nl_cache_dump	(	struct nl_cache *	cache,
		struct nl_dump_params *	params
	)

Dump all elements of a cache.

Parameters

cache	cache to dump
params	dumping parameters

Dumps all elements of the cache to the file descriptor fd.

Definition at line 1122 of file cache.c.

References nl_cache_dump_filter().

Referenced by nl_cache_mngr_info().

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void nl_cache_dump_filter	(	struct nl_cache *	cache,
		struct nl_dump_params *	params,
		struct nl_object *	filter
	)

Dump all elements of a cache (filtered).

Parameters

cache	cache to dump
params	dumping parameters (optional)
filter	filter object

Dumps all elements of the cache to the file descriptor fd given they match the given filter filter.

Definition at line 1136 of file cache.c.

References nl_dump_params::dp_buf, nl_dump_params::dp_buflen, nl_dump_params::dp_type, NL_DUMP_DETAILS, and nl_object_match_filter().

Referenced by nl_cache_dump().

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void nl_cache_foreach	(	struct nl_cache *	cache,
		void()(struct nl_object , void *)	cb,
		void *	arg
	)

Call a callback on each element of the cache.

Parameters

cache	cache to iterate on
cb	callback function
arg	argument passed to callback function

Calls a callback function cb on each element of the cache. The argument arg is passed on the callback function.

Definition at line 1185 of file cache.c.

References nl_cache_foreach_filter().

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void nl_cache_foreach_filter	(	struct nl_cache *	cache,
		struct nl_object *	filter,
		void()(struct nl_object , void *)	cb,
		void *	arg
	)

Call a callback on each element of the cache (filtered).

Parameters

cache	cache to iterate on
filter	filter object
cb	callback function
arg	argument passed to callback function

Calls a callback function cb on each element of the cache that matches the filter. The argument arg is passed on to the callback function.

Definition at line 1202 of file cache.c.

References nl_object_get(), nl_object_match_filter(), and nl_object_put().

Referenced by nl_cache_foreach(), rtnl_class_foreach_child(), rtnl_class_foreach_cls(), rtnl_qdisc_foreach_child(), and rtnl_qdisc_foreach_cls().

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Macros

Access Functions

Cache Allocation/Deletion

Cache Modifications

Synchronization

Parsing

Utillities

Dumping

Iterators

Detailed Description

Header

Function Documentation