libnl  3.2.3
Cache

Modules

 Object
 Cache Implementation

Access Functions

int nl_cache_nitems (struct nl_cache *cache)
 Return the number of items in the cache.
int nl_cache_nitems_filter (struct nl_cache *cache, struct nl_object *filter)
 Return the number of items matching a filter in the cache.
int nl_cache_is_empty (struct nl_cache *cache)
 Returns true if the cache is empty.
struct nl_cache_opsnl_cache_get_ops (struct nl_cache *cache)
 Return the operations set of the cache.
struct nl_objectnl_cache_get_first (struct nl_cache *cache)
 Return the first element in the cache.
struct nl_objectnl_cache_get_last (struct nl_cache *cache)
 Return the last element in the cache.
struct nl_objectnl_cache_get_next (struct nl_object *obj)
 Return the next element in the cache.
struct nl_objectnl_cache_get_prev (struct nl_object *obj)
 Return the previous element in the cache.

Cache Allocation/Deletion

struct nl_cache * nl_cache_alloc (struct nl_cache_ops *ops)
 Allocate new cache.
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.
int nl_cache_alloc_name (const char *kind, struct nl_cache **result)
 Allocate new cache based on type name.
struct nl_cache * nl_cache_subset (struct nl_cache *orig, struct nl_object *filter)
 Allocate new cache containing a subset of an existing cache.
void nl_cache_clear (struct nl_cache *cache)
 Remove all objects of a cache.
void nl_cache_free (struct nl_cache *cache)
 Free a cache.

Cache Modifications

int nl_cache_add (struct nl_cache *cache, struct nl_object *obj)
 Add object to cache.
int nl_cache_move (struct nl_cache *cache, struct nl_object *obj)
 Move object from one cache to another.
void nl_cache_remove (struct nl_object *obj)
 Remove object from cache.

Synchronization

void nl_cache_set_arg1 (struct nl_cache *cache, int arg)
 Set synchronization arg1 of cache.
void nl_cache_set_arg2 (struct nl_cache *cache, int arg)
 Set synchronization arg2 of cache.
int nl_cache_pickup (struct nl_sock *sk, struct nl_cache *cache)
 Pickup a netlink dump response and put it into a cache.
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.
int nl_cache_refill (struct nl_sock *sk, struct nl_cache *cache)
 (Re)fill a cache with the contents in the kernel.

Utillities

struct nl_objectnl_cache_search (struct nl_cache *cache, struct nl_object *needle)
 Search object in cache.
void nl_cache_mark_all (struct nl_cache *cache)
 Mark all objects of a cache.

Dumping

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

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.
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).

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

Function Documentation

int nl_cache_nitems ( struct nl_cache *  cache)

Return the number of items in the cache.

Parameters:
cachecache handle

Definition at line 58 of file cache.c.

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:
cacheCache object.
filterFilter object.

Definition at line 68 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:
cacheCache to check
Returns:
true if the cache is empty, otherwise false is returned.

Definition at line 91 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:
cachecache handle

Definition at line 100 of file cache.c.

struct nl_object* nl_cache_get_first ( struct nl_cache *  cache) [read]

Return the first element in the cache.

Parameters:
cachecache handle

Definition at line 109 of file cache.c.

struct nl_object* nl_cache_get_last ( struct nl_cache *  cache) [read]

Return the last element in the cache.

Parameters:
cachecache handle

Definition at line 122 of file cache.c.

struct nl_object* nl_cache_get_next ( struct nl_object obj) [read]

Return the next element in the cache.

Parameters:
objcurrent object

Definition at line 135 of file cache.c.

struct nl_object* nl_cache_get_prev ( struct nl_object obj) [read]

Return the previous element in the cache.

Parameters:
objcurrent object

Definition at line 148 of file cache.c.

struct nl_cache* nl_cache_alloc ( struct nl_cache_ops ops) [read]

Allocate new cache.

Parameters:
opsCache operations

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

Returns:
Allocated cache or NULL if allocation failed.

Definition at line 173 of file cache.c.

Referenced by flnl_result_alloc_cache(), nl_cache_alloc_and_fill(), nl_cache_alloc_name(), 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:
opsCache operations
sockNetlink socket
resultResult 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 205 of file cache.c.

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

Referenced by nfnl_ct_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:
kindName of cache type
resultResult 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 236 of file cache.c.

References nl_cache_alloc(), and nl_cache_ops_lookup().

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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:
origOriginal cache to base new cache on
filterFilter 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 267 of file cache.c.

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

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void nl_cache_clear ( struct nl_cache *  cache)

Remove all objects of a cache.

Parameters:
cacheCache 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 301 of file cache.c.

References nl_cache_remove().

Referenced by nl_cache_free(), and nl_cache_refill().

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void nl_cache_free ( struct nl_cache *  cache)

Free a cache.

Parameters:
cacheCache 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 320 of file cache.c.

References nl_cache_clear().

Referenced by genl_ctrl_resolve(), nl_cache_alloc_and_fill(), nl_cache_mngr_add(), nl_cache_mngr_free(), 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:
cacheCache
objObject 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 372 of file cache.c.

References nl_object_clone(), and nl_object_get().

Referenced by 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:
cacheCache to move object to.
objObject 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 409 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:
objObject 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 436 of file cache.c.

References 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:
cacheCache
argargument

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

Definition at line 467 of file cache.c.

void nl_cache_set_arg2 ( struct nl_cache *  cache,
int  arg 
)

Set synchronization arg2 of cache.

Parameters:
cacheCache
argargument

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

Definition at line 480 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:
skNetlink socket.
cacheCache to put items into.

Waits for netlink messages to arrive, parses them and puts them into the specified cache.

Returns:
0 on success or a negative error code.

Definition at line 586 of file cache.c.

References nl_parser_param::pp_cb.

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:
cachecache to add element to
msgnetlink message

Parses a netlink message by calling the cache specific message parser and adds the new element to the cache.

Returns:
0 or a negative error code.

Definition at line 747 of file cache.c.

References nlmsg_hdr(), and nl_parser_param::pp_cb.

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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:
skNetlink socket.
cachecache 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 767 of file cache.c.

References nl_cache_clear(), and nl_cache_pickup().

Referenced by nl_cache_alloc_and_fill(), nl_cache_mngr_add(), 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:
cacheCache
needleObject 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 811 of file cache.c.

References nl_object_get(), and nl_object_identical().

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void nl_cache_mark_all ( struct nl_cache *  cache)

Mark all objects of a cache.

Parameters:
cacheCache

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

Definition at line 833 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:
cachecache to dump
paramsdumping parameters

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

Definition at line 858 of file cache.c.

References nl_cache_dump_filter().

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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:
cachecache to dump
paramsdumping parameters (optional)
filterfilter object

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

Definition at line 872 of file cache.c.

References nl_dump_params::dp_type, NL_DUMP_DETAILS, nl_object_match_filter(), and nl_object_ops::oo_dump.

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:
cachecache to iterate on
cbcallback function
argargument 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 918 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:
cachecache to iterate on
filterfilter object
cbcallback function
argargument 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 935 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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