1.\" 2.\" Copyright (c) 2004 Bruce M. Simpson <bms@spc.org> 3.\" Copyright (c) 2004 Darron Broad <darron@kewl.org> 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25.\" SUCH DAMAGE. 26.\" 27.\" $FreeBSD$ 28.\" $Id: ieee80211_node.9,v 1.6 2004/03/04 12:33:27 bruce Exp $ 29.\" 30.Dd July 4, 2004 31.Dt IEEE80211_NODE 9 32.Os 33.Sh NAME 34.Nm ieee80211_node_attach , 35.Nm ieee80211_node_lateattach , 36.Nm ieee80211_node_detach , 37.Nm ieee80211_begin_scan , 38.Nm ieee80211_next_scan , 39.Nm ieee80211_create_ibss , 40.Nm ieee80211_end_scan , 41.Nm ieee80211_alloc_node , 42.Nm ieee80211_dup_bss , 43.Nm ieee80211_find_node , 44.Nm ieee80211_lookup_node , 45.Nm ieee80211_free_node , 46.Nm ieee80211_free_allnodes , 47.Nm ieee80211_timeout_nodes , 48.Nm ieee80211_iterate_nodes 49.Nd software 802.11 stack node management functions 50.Sh SYNOPSIS 51.In net80211/ieee80211_var.h 52.In net80211/ieee80211_proto.h 53.In net80211/ieee80211_node.h 54.Ft void 55.Fn ieee80211_node_attach "struct ifnet *ifp" 56.Ft void 57.Fn ieee80211_node_lateattach "struct ifnet *ifp" 58.Ft void 59.Fn ieee80211_node_detach "struct ifnet *ifp" 60.Ft void 61.Fn ieee80211_begin_scan "struct ifnet *ifp" 62.Ft void 63.Fn ieee80211_next_scan "struct ifnet *ifp" 64.Ft void 65.Fo ieee80211_create_ibss 66.Fa "struct ieee80211com *ic" "struct ieee80211_channel *chan" 67.Fc 68.Ft void 69.Fn ieee80211_end_scan "struct ifnet *ifp" 70.Ft struct ieee80211_node * 71.Fn ieee80211_alloc_node "struct ieee80211com *ic" "u_int8_t *macaddr" 72.Ft struct ieee80211_node * 73.Fn ieee80211_dup_bss "struct ieee80211com *ic" "u_int8_t *macaddr" 74.Ft struct ieee80211_node * 75.Fn ieee80211_find_node "struct ieee80211com *ic" "u_int8_t *macaddr" 76.Ft struct ieee80211_node * 77.Fo ieee80211_lookup_node 78.Fa "struct ieee80211com *ic" "u_int8_t *macaddr" 79.Fa "struct ieee80211_channel *chan" 80.Fc 81.Ft void 82.Fn ieee80211_free_node "struct ieee80211com *ic" "struct ieee80211_node *ni" 83.Ft void 84.Fn ieee80211_free_allnodes "struct ieee80211com *ic" 85.Ft void 86.Fn ieee80211_timeout_nodes "struct ieee80211com *ic" 87.Ft void 88.Fo ieee80211_iterate_nodes 89.Fa "struct ieee80211com *ic" "ieee80211_iter_func *f" "void *arg" 90.Fc 91.Sh DESCRIPTION 92These functions are used to manage node lists within the software 93802.11 stack. 94These lists are typically used for implementing host-mode AP functionality, 95or providing signal quality information about neighbouring nodes. 96.Pp 97.\" 98The 99.Fn ieee80211_node_attach 100function is called from 101.Xr ieee80211_ifattach 9 102to initialize node database management callbacks for the interface 103.Fa ifp 104(specifically for memory allocation, node copying and node 105signal inspection). 106These functions may be overridden in special circumstances, 107as long as this is done after calling 108.Xr ieee80211_ifattach 9 109and prior to any other call which may allocate a node. 110.Pp 111.\" 112The 113.Fn ieee80211_node_lateattach 114function initialises the 115.Va ic_bss 116node element of the interface 117.Fa ifp 118during 119.Xr ieee80211_media_init 9 . 120This late attachment is to account for certain special cases described under 121.Fn ieee80211_node_attach . 122.Pp 123.\" 124The 125.Fn ieee80211_node_detach 126function destroys all node database state associated with the interface 127.Fa ifp , 128and is usually called during device detach. 129.Pp 130.\" 131The 132.Fn ieee80211_begin_scan 133function initialises the node database in preparation of an active 134scan for an access point on the interface 135.Fa ifp . 136The scan begins on the next radio channel by calling 137.Fn ieee80211_next_scan 138internally. 139The actual scanning for an access point is not automated; 140the device driver itself only handles setting the radio frequency 141of the card and stepping through the channels. 142.Pp 143.\" 144The 145.Fn ieee80211_next_scan 146function is used to inform the 147.Xr ieee80211 9 148layer that the interface 149.Fa ifp 150is now scanning for an access point on the next radio channel. 151A device driver is expected to first call 152.Fn ieee80211_begin_scan , 153to initialize the node database, 154then set the radio channel on the device; 155then, after a certain time has elapsed (200ms for example), call 156.Fn ieee80211_next_scan 157to move to the next channel. 158Typically, a callout is used to automate this process; see 159.Xr callout_init 9 160for more information on how to use callouts. 161.Pp 162.\" 163The 164.Fn ieee80211_create_ibss 165function sets up the net80211-specific portion of an interface's softc, 166.Fa ic , 167for use in IBSS mode. 168.Pp 169.\" 170The 171.Fn ieee80211_end_scan 172function is called by 173.Fn ieee80211_next_scan 174when the state machine has peformed a full cycle of scanning on 175all available radio channels. 176Internally, 177.Fn ieee80211_end_scan 178will inspect the node cache associated with the interface 179.Fa ifp 180for suitable access points found during scanning, and associate with one, 181should the parameters of the node match those of the configuration 182requested from userland. 183.Pp 184.\" 185The 186.Fn ieee80211_alloc_node 187function allocates an instance of 188.Vt "struct ieee80211_node" 189for a node having the MAC address 190.Fa macaddr , 191and associates it with the interface 192.Fa ic . 193If the allocation is successful, the node structure is initialised by 194.Fn ieee80211_setup_node ; 195otherwise, 196.Dv NULL 197is returned. 198.Pp 199.\" 200The 201.Fn ieee80211_dup_bss 202function is similar to 203.Fn ieee80211_alloc_node , 204but is instead used to create a node database entry for the BSSID 205.Fa macaddr 206associated with the interface 207.Fa ic . 208If the allocation is successful, the node structure is initialised by 209.Fn ieee80211_setup_node ; 210otherwise, 211.Dv NULL 212is returned. 213.Pp 214.\" 215The 216.Fn ieee80211_find_node 217function will iterate through the node list associated with the interface 218.Fa ic , 219searching for a node entry which matches 220.Fa macaddr . 221If the entry is found, its reference count is incremented, and 222a pointer to the node is returned; otherwise, 223.Dv NULL 224will be returned. 225.Pp 226.\" 227The 228.Fn ieee80211_lookup_node 229function is similar to 230.Fn ieee80211_find_node , 231with an additional argument 232.Fa chan 233which is used to specify a channel for the match. 234If the entry is found, its reference count is incremented, and 235a pointer to the node is returned; otherwise, 236.Dv NULL 237will be returned. 238.Pp 239.\" 240The 241.Fn ieee80211_free_node 242function will remove the node 243.Fa ni 244from the node database entries associated with the interface 245.Fa ic , 246and free any memory associated with the node. 247This private method can be overridden in 248.Fn ieee80211_node_attach . 249.\" 250.Pp 251The 252.Fn ieee80211_free_allnodes 253function will iterate through the node list calling 254.Fn ieee80211_free_node 255for all nodes associated with the interface 256.Fa ic . 257.Pp 258.\" 259The 260.Fn ieee80211_timeout_nodes 261checks if the inactivity timer of each node associated with the interface 262.Fa ic 263has exceeded the pre-defined constant 264.Dv IEEE80211_INACT_MAX . 265If so, then the node is freed, after sending a deauthentication message. 266.Pp 267.\" 268The 269.Fn ieee80211_iterate_nodes 270function will call the user-defined callback function 271.Fa f 272for all nodes in the node database associated with the interface 273.Fa ic . 274The callback is invoked with the with the user-supplied value 275.Fa arg 276and a pointer to the current node. 277.\" 278.Sh SEE ALSO 279.Xr ieee80211 9 , 280.Xr ifnet 9 281.Sh HISTORY 282The 283.Nm ieee80211 284series of functions first appeared in 285.Nx 1.5 , 286and were later ported to 287.Fx 4.6 . 288.Sh AUTHORS 289.An -nosplit 290This man page was written by 291.An Bruce M. Simpson Aq bms@FreeBSD.org 292and 293.An Darron Broad Aq darron@kewl.org . 294