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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

     #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, u_int8_t *macaddr);

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

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

     struct ieee80211_node *
     ieee80211_lookup_node(struct ieee80211com *ic, u_int8_t *macaddr,
             struct ieee80211_channel *chan);

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

     void
     ieee80211_free_allnodes(struct ieee80211com *ic);

     void
     ieee80211_timeout_nodes(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 callout is used to automate this process; see
     callout_init(9) for more information on how to use callouts.

     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 peformed 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_lookup_node() function is similar to ieee80211_find_node(),
     with an additional argument 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 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_timeout_nodes() checks if the inactivity timer of each node
     associated with the interface ic has exceeded the pre-defined constant
     IEEE80211_INACT_MAX.  If so, then the node is freed, after sending a
     deauthentication message.

     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), ifnet(9)

HISTORY

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

AUTHORS

     This manual page was written by Bruce M. Simpson 〈bms@FreeBSD.org〉 and
     Darron Broad 〈darron@kewl.org〉.