IEEE80211_NODE_ATTACH(9) | Kernel Developer's Manual | IEEE80211_NODE_ATTACH(9)

# 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_release_node`, `ieee80211_free_node`, `ieee80211_free_allnodes`, `ieee80211_iterate_nodes` — software 802.11 stack node management functions

# SYNOPSIS

`#include <net80211/ieee80211_var.h>`
`#include <net80211/ieee80211_proto.h>`
`#include <net80211/ieee80211_node.h>`

void
`ieee80211_node_attach`(struct ifnet *ifp);

void
`ieee80211_node_lateattach`(struct ifnet *ifp);

void
`ieee80211_node_detach`(struct ifnet *ifp);

void
`ieee80211_begin_scan`(struct ifnet *ifp);

void
`ieee80211_next_scan`(struct ifnet *ifp);

void
`ieee80211_create_ibss`(struct ieee80211com *ic, struct ieee80211_channel *chan);

void
`ieee80211_end_scan`(struct ifnet *ifp);

struct ieee80211_node *
`ieee80211_alloc_node`(struct ieee80211com *ic, const u_int8_t *macaddr);

struct ieee80211_node *
`ieee80211_dup_bss`(struct ieee80211com *ic, const u_int8_t *macaddr);

struct ieee80211_node *
`ieee80211_find_node`(struct ieee80211com *ic, const u_int8_t *macaddr);

void
`ieee80211_release_node`(struct ieee80211com *ic, struct ieee80211_node *ni);

void
`ieee80211_free_node`(struct ieee80211com *ic, struct ieee80211_node *ni);

void
`ieee80211_free_allnodes`(struct ieee80211com *ic);

void
`ieee80211_iterate_nodes`(struct ieee80211com *ic, ieee80211_iter_func *f, void *arg);

# 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 `ieee80211_node_attach`() function is called from ieee80211_ifattach(9) to initialize node database management callbacks for the interface 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_ifattach(9) and prior to any other call which may allocate a node.

The `ieee80211_node_lateattach`() function initialises the ic_bss node element of the interface ifp during ieee80211_media_init(9). This late attachment is to account for certain special cases described under `ieee80211_node_attach`().

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

The `ieee80211_begin_scan`() function initialises the node database in preparation of an active scan for an access point on the interface ifp. The scan begins on the next radio channel by calling `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 `ieee80211_next_scan`() function is used to inform the ieee80211(9) layer that the interface ifp is now scanning for an access point on the next radio channel. A device driver is expected to first call `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 `ieee80211_next_scan`() to move to the next channel. Typically, a timeout is used to automate this process; see timeout(9) for more information on how to use timeouts.

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

The `ieee80211_end_scan`() function is called by `ieee80211_next_scan`() when the state machine has performed a full cycle of scanning on all available radio channels. Internally, `ieee80211_end_scan`() will inspect the node cache associated with the interface 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 `ieee80211_alloc_node`() function allocates an instance of struct ieee80211_node for a node having the MAC address macaddr, and associates it with the interface ic. If the allocation is successful, the node structure is initialised by `ieee80211_setup_node`(); otherwise, `NULL` is returned.

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

The `ieee80211_find_node`() function will iterate through the node list associated with the interface ic, searching for a node entry which matches 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 `ieee80211_free_node`() function will remove the node ni from the node database entries associated with the interface ic, and free any memory associated with the node. This private method can be overridden in `ieee80211_node_attach`().

The `ieee80211_free_allnodes`() function will iterate through the node list calling `ieee80211_free_node`() for all nodes associated with the interface ic.

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

# SEE ALSO

ieee80211(9)

# HISTORY

The `ieee80211` series of functions first appeared in NetBSD 1.5, and were later ported to FreeBSD 4.6 and OpenBSD 3.6.

# AUTHORS

This man page was written by Bruce M. Simpson <bms@FreeBSD.org> and Darron Broad <darron@kewl.org>.

November 23, 2015 | Debian