Callbacks/Customization

Collaboration diagram for Callbacks/Customization:

Enumerations
enum	nl_cb_action {   NL_OK,   NL_SKIP,   NL_STOP }
	Callback actions. More...
enum	nl_cb_kind {   NL_CB_DEFAULT,   NL_CB_VERBOSE,   NL_CB_DEBUG,   NL_CB_CUSTOM,   __NL_CB_KIND_MAX }
	Callback kinds. More...
enum	nl_cb_type {   NL_CB_VALID,   NL_CB_FINISH,   NL_CB_OVERRUN,   NL_CB_SKIPPED,   NL_CB_ACK,   NL_CB_MSG_IN,   NL_CB_MSG_OUT,   NL_CB_INVALID,   NL_CB_SEQ_CHECK,   NL_CB_SEND_ACK,   __NL_CB_TYPE_MAX }
	Callback types. More...

Callback Typedefs
typedef int(*	nl_recvmsg_msg_cb_t )(struct nl_msg *msg, void *arg)
	nl_recvmsgs() callback for message processing customization More...
typedef int(*	nl_recvmsg_err_cb_t )(struct sockaddr_nl *nla, struct nlmsgerr *nlerr, void *arg)
	nl_recvmsgs() callback for error message processing customization More...

Callback Handle Management
struct nl_cb *	nl_cb_alloc (enum nl_cb_kind kind)
	Allocate a new callback handle. More...
struct nl_cb *	nl_cb_clone (struct nl_cb *orig)
	Clone an existing callback handle. More...
struct nl_cb *	nl_cb_get (struct nl_cb *cb)
void	nl_cb_put (struct nl_cb *cb)

Callback Setup
int	nl_cb_set (struct nl_cb *cb, enum nl_cb_type type, enum nl_cb_kind kind, nl_recvmsg_msg_cb_t func, void *arg)
	Set up a callback. More...
int	nl_cb_set_all (struct nl_cb *cb, enum nl_cb_kind kind, nl_recvmsg_msg_cb_t func, void *arg)
	Set up a all callbacks. More...
int	nl_cb_err (struct nl_cb *cb, enum nl_cb_kind kind, nl_recvmsg_err_cb_t func, void *arg)
	Set up an error callback. More...

Overwriting
void	nl_cb_overwrite_recvmsgs (struct nl_cb *cb, int(*func)(struct nl_sock *, struct nl_cb *))
	Overwrite internal calls to nl_recvmsgs() More...
void	nl_cb_overwrite_recv (struct nl_cb *cb, int(*func)(struct nl_sock *, struct sockaddr_nl *, unsigned char **, struct ucred **))
	Overwrite internal calls to nl_recv() More...
void	nl_cb_overwrite_send (struct nl_cb *cb, int(*func)(struct nl_sock *, struct nl_msg *))
	Overwrite internal calls to nl_send() More...

Detailed Description

1) Setting up a callback set

// Allocate a callback set and initialize it to the verbose default set
struct nl_cb *cb = nl_cb_alloc(NL_CB_VERBOSE);

// Modify the set to call my_func() for all valid messages
nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, my_func, NULL);

// Set the error message handler to the verbose default implementation
// and direct it to print all errors to the given file descriptor.
FILE *file = fopen(...);
nl_cb_err(cb, NL_CB_VERBOSE, NULL, file);

Typedef Documentation

typedef int(* nl_recvmsg_err_cb_t)(struct sockaddr_nl *nla, struct nlmsgerr *nlerr, void *arg)

nl_recvmsgs() callback for error message processing customization

• nla netlink address of the peer
• nlerr netlink error message being processed
• arg argument passed on through caller

typedef int(* nl_recvmsg_msg_cb_t)(struct nl_msg *msg, void *arg)

nl_recvmsgs() callback for message processing customization

• msg netlink message being processed
• arg argument passwd on through caller

Enumeration Type Documentation

enum nl_cb_action

Callback actions.

Enumerator
NL_OK	Proceed with wathever would come next.
NL_SKIP	Skip this message.
NL_STOP	Stop parsing altogether and discard remaining messages.

enum nl_cb_kind

Callback kinds.

Enumerator
NL_CB_DEFAULT	Default handlers (quiet)
NL_CB_VERBOSE	Verbose default handlers (error messages printed)
NL_CB_DEBUG	Debug handlers for debugging.
NL_CB_CUSTOM	Customized handler specified by the user.
__NL_CB_KIND_MAX

enum nl_cb_type

Callback types.

Enumerator
NL_CB_VALID	Message is valid.
NL_CB_FINISH	Last message in a series of multi part messages received.
NL_CB_OVERRUN	Report received that data was lost.
NL_CB_SKIPPED	Message wants to be skipped.
NL_CB_ACK	Message is an acknowledge.
NL_CB_MSG_IN	Called for every message received.
NL_CB_MSG_OUT	Called for every message sent out except for nl_sendto()
NL_CB_INVALID	Message is malformed and invalid.
NL_CB_SEQ_CHECK	Called instead of internal sequence number checking.
NL_CB_SEND_ACK	Sending of an acknowledge message has been requested.
__NL_CB_TYPE_MAX

Function Documentation

struct nl_cb* nl_cb_alloc

(

enum nl_cb_kind

kind

)

Allocate a new callback handle.

• kind callback kind to be used for initialization

  Returns

  Newly allocated callback handle or NULL

References nl_cb::cb_refcnt, nl_cb_err(), NL_CB_KIND_MAX, nl_cb_set(), NL_CB_TYPE_MAX, and NULL.

Referenced by nl_cb_clone(), and nl_socket_alloc().

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struct nl_cb* nl_cb_clone

(

struct nl_cb *

orig

)

Clone an existing callback handle.

• orig original callback handle

  Returns

  Newly allocated callback handle being a duplicate of orig or NULL

References nl_cb::cb_refcnt, nl_cb_alloc(), NL_CB_DEFAULT, and NULL.

Referenced by __cache_pickup(), and nl_wait_for_ack().

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int nl_cb_err	(	struct nl_cb *	cb,
		enum nl_cb_kind	kind,
		nl_recvmsg_err_cb_t	func,
		void *	arg
	)

Set up an error callback.

• cb callback set
• kind kind of callback
• func callback function
• arg argument to be passed to callback function

References nl_cb::cb_err, nl_cb::cb_err_arg, NL_CB_CUSTOM, NL_CB_KIND_MAX, and NLE_RANGE.

Referenced by nl_cb_alloc().

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struct nl_cb* nl_cb_get

(

struct nl_cb *

cb

)

References nl_cb::cb_refcnt.

Referenced by nl_socket_alloc_cb(), nl_socket_get_cb(), and nl_socket_set_cb().

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void nl_cb_overwrite_recv	(	struct nl_cb *	cb,
		int(*)(struct nl_sock *, struct sockaddr_nl *, unsigned char **, struct ucred **)	func
	)

Overwrite internal calls to nl_recv()

• cb callback set
• func replacement callback for nl_recv()

References nl_cb::cb_recv_ow.

void nl_cb_overwrite_recvmsgs	(	struct nl_cb *	cb,
		int(*)(struct nl_sock *, struct nl_cb *)	func
	)

Overwrite internal calls to nl_recvmsgs()

• cb callback set
• func replacement callback for nl_recvmsgs()

References nl_cb::cb_recvmsgs_ow.

void nl_cb_overwrite_send	(	struct nl_cb *	cb,
		int(*)(struct nl_sock *, struct nl_msg *)	func
	)

Overwrite internal calls to nl_send()

• cb callback set
• func replacement callback for nl_send()

References nl_cb::cb_send_ow.

void nl_cb_put

(

struct nl_cb *

cb

)

References BUG, and nl_cb::cb_refcnt.

Referenced by __cache_pickup(), nl_socket_free(), nl_socket_set_cb(), and nl_wait_for_ack().

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int nl_cb_set	(	struct nl_cb *	cb,
		enum nl_cb_type	type,
		enum nl_cb_kind	kind,
		nl_recvmsg_msg_cb_t	func,
		void *	arg
	)

Set up a callback.

• cb callback set
• type callback to modify
• kind kind of implementation
• func callback function (NL_CB_CUSTOM)
• arg argument passed to callback

Returns

0 on success or a negative error code

References nl_cb::cb_args, nl_cb::cb_set, NL_CB_CUSTOM, NL_CB_KIND_MAX, NL_CB_TYPE_MAX, NLE_RANGE, and type.

Referenced by __cache_pickup(), nl_cb_alloc(), nl_cb_set_all(), nl_socket_disable_seq_check(), nl_socket_modify_cb(), and nl_wait_for_ack().

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int nl_cb_set_all	(	struct nl_cb *	cb,
		enum nl_cb_kind	kind,
		nl_recvmsg_msg_cb_t	func,
		void *	arg
	)

Set up a all callbacks.

• cb callback set
• kind kind of callback
• func callback function
• arg argument to be passwd to callback function

Returns

0 on success or a negative error code

References nl_cb_set(), and NL_CB_TYPE_MAX.

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