ieee80211_begin_scan.9freebsd

Langue: en

Version: 307281 (debian - 07/07/09)

Section: 9 (Appels noyau Linux)


BSD mandoc

NAME

ieee80211_node_attach ieee80211_node_lateattach ieee80211_node_detach ieee80211_begin_scan ieee80211_next_scan ieee80211_create_ibss ieee80211_end_scan ieee80211_alloc_node ieee80211_dup_bss ieee80211_find_node ieee80211_lookup_node ieee80211_free_node ieee80211_free_allnodes ieee80211_timeout_nodes ieee80211_iterate_nodes - software 802.11 stack node management functions

SYNOPSIS

In net80211/ieee80211_var.h In net80211/ieee80211_proto.h In net80211/ieee80211_node.h Ft void Fn ieee80211_node_attach struct ifnet *ifp Ft void Fn ieee80211_node_lateattach struct ifnet *ifp Ft void Fn ieee80211_node_detach struct ifnet *ifp Ft void Fn ieee80211_begin_scan struct ifnet *ifp Ft void Fn ieee80211_next_scan struct ifnet *ifp Ft void Fo ieee80211_create_ibss Fa struct ieee80211com *ic struct ieee80211_channel *chan Fc Ft void Fn ieee80211_end_scan struct ifnet *ifp Ft struct ieee80211_node * Fn ieee80211_alloc_node struct ieee80211com *ic u_int8_t *macaddr Ft struct ieee80211_node * Fn ieee80211_dup_bss struct ieee80211com *ic u_int8_t *macaddr Ft struct ieee80211_node * Fn ieee80211_find_node struct ieee80211com *ic u_int8_t *macaddr Ft struct ieee80211_node * Fo ieee80211_lookup_node Fa struct ieee80211com *ic u_int8_t *macaddr Fa struct ieee80211_channel *chan Fc Ft void Fn ieee80211_free_node struct ieee80211com *ic struct ieee80211_node *ni Ft void Fn ieee80211_free_allnodes struct ieee80211com *ic Ft void Fn ieee80211_timeout_nodes struct ieee80211com *ic Ft void Fo ieee80211_iterate_nodes Fa struct ieee80211com *ic ieee80211_iter_func *f void *arg Fc  

DESCRIPTION

These functions are used to manage node lists within the software 802.11 stack. These lists are typically used for implementing host-mode AP functionality, or providing signal quality information about neighbouring nodes.

The Fn ieee80211_node_attach function is called from ieee80211_ifattach9 to initialize node database management callbacks for the interface Fa ifp (specifically for memory allocation, node copying and node signal inspection). These functions may be overridden in special circumstances, as long as this is done after calling ieee80211_ifattach9 and prior to any other call which may allocate a node.

The Fn ieee80211_node_lateattach function initialises the ic_bss node element of the interface Fa ifp during ieee80211_media_init9. This late attachment is to account for certain special cases described under Fn ieee80211_node_attach .

The Fn ieee80211_node_detach function destroys all node database state associated with the interface Fa ifp , and is usually called during device detach.

The Fn ieee80211_begin_scan function initialises the node database in preparation of an active scan for an access point on the interface Fa ifp . The scan begins on the next radio channel by calling Fn ieee80211_next_scan internally. The actual scanning for an access point is not automated; the device driver itself only handles setting the radio frequency of the card and stepping through the channels.

The Fn ieee80211_next_scan function is used to inform the ieee80211(9) layer that the interface Fa ifp is now scanning for an access point on the next radio channel. A device driver is expected to first call Fn ieee80211_begin_scan , to initialize the node database, then set the radio channel on the device; then, after a certain time has elapsed (200ms for example), call Fn ieee80211_next_scan to move to the next channel. Typically, a callout is used to automate this process; see callout_init9 for more information on how to use callouts.

The Fn ieee80211_create_ibss function sets up the net80211-specific portion of an interface's softc, Fa ic , for use in IBSS mode.

The Fn ieee80211_end_scan function is called by Fn ieee80211_next_scan when the state machine has peformed a full cycle of scanning on all available radio channels. Internally, Fn ieee80211_end_scan will inspect the node cache associated with the interface Fa ifp for suitable access points found during scanning, and associate with one, should the parameters of the node match those of the configuration requested from userland.

The Fn ieee80211_alloc_node function allocates an instance of Vt struct ieee80211_node for a node having the MAC address Fa macaddr , and associates it with the interface Fa ic . If the allocation is successful, the node structure is initialised by Fn ieee80211_setup_node ; otherwise, NULL is returned.

The Fn ieee80211_dup_bss function is similar to Fn ieee80211_alloc_node , but is instead used to create a node database entry for the BSSID Fa macaddr associated with the interface Fa ic . If the allocation is successful, the node structure is initialised by Fn ieee80211_setup_node ; otherwise, NULL is returned.

The Fn ieee80211_find_node function will iterate through the node list associated with the interface Fa ic , searching for a node entry which matches Fa macaddr . If the entry is found, its reference count is incremented, and a pointer to the node is returned; otherwise, NULL will be returned.

The Fn ieee80211_lookup_node function is similar to Fn ieee80211_find_node , with an additional argument Fa chan which is used to specify a channel for the match. If the entry is found, its reference count is incremented, and a pointer to the node is returned; otherwise, NULL will be returned.

The Fn ieee80211_free_node function will remove the node Fa ni from the node database entries associated with the interface Fa ic , and free any memory associated with the node. This private method can be overridden in Fn ieee80211_node_attach .

The Fn ieee80211_free_allnodes function will iterate through the node list calling Fn ieee80211_free_node for all nodes associated with the interface Fa ic .

The Fn ieee80211_timeout_nodes checks if the inactivity timer of each node associated with the interface Fa ic has exceeded the pre-defined constant IEEE80211_INACT_MAX If so, then the node is freed, after sending a deauthentication message.

The Fn ieee80211_iterate_nodes function will call the user-defined callback function Fa f for all nodes in the node database associated with the interface Fa ic . The callback is invoked with the with the user-supplied value Fa arg and a pointer to the current node.

SEE ALSO

ieee80211(9), ifnet(9)

HISTORY

The ieee80211 series of functions first appeared in Nx 1.5 , and were later ported to Fx 4.6 .

AUTHORS

An -nosplit This manual page was written by An Bruce M. Simpson Aq bms@FreeBSD.org and An Darron Broad Aq darron@kewl.org .