Update wireless documentation
[openwrt/openwrt.git] / docs / wireless.tex
1 The WiFi settings are configured in the file \texttt{/etc/config/wireless}
2 (currently supported on Broadcom, Atheros and mac80211). When booting the router for the first time
3 it should detect your card and create a sample configuration file. By default '\texttt{option network lan}' is
4 commented. This prevents unsecured sharing of the network over the wireless interface.
5
6 Each wireless driver has its own configuration script in \texttt{/lib/wifi/driver\_name.sh} which handles
7 driver specific options and configurations. This script is also calling driver specific binaries like wlc for
8 Broadcom, or hostapd and wpa\_supplicant for atheros.
9
10 The reason for using such architecture, is that it abstracts the driver configuration.
11
12 \paragraph{Generic Broadcom wireless config:}
13
14 \begin{Verbatim}
15 config wifi-device "wl0"
16 option type "broadcom"
17 option channel "5"
18
19 config wifi-iface
20 option device "wl0"
21 # option network lan
22 option mode "ap"
23 option ssid "OpenWrt"
24 option hidden "0"
25 option encryption "none"
26 \end{Verbatim}
27
28 \paragraph{Generic Atheros wireless config:}
29
30 \begin{Verbatim}
31 config wifi-device "wifi0"
32 option type "atheros"
33 option channel "5"
34 option agmode "11g"
35
36 config wifi-iface
37 option device "wifi0"
38 # option network lan
39 option mode "ap"
40 option ssid "OpenWrt"
41 option hidden "0"
42 option encryption "none"
43 \end{Verbatim}
44
45 \paragraph{Generic mac80211 wireless config:}
46
47 \begin{Verbatim}
48 config wifi-device "wifi0"
49 option type "mac80211"
50 option channel "5"
51
52 config wifi-iface
53 option device "wlan0"
54 # option network lan
55 option mode "ap"
56 option ssid "OpenWrt"
57 option hidden "0"
58 option encryption "none"
59 \end{Verbatim}
60
61 \paragraph{Generic multi-radio Atheros wireless config:}
62
63 \begin{Verbatim}
64 config wifi-device wifi0
65 option type atheros
66 option channel 1
67
68 config wifi-iface
69 option device wifi0
70 # option network lan
71 option mode ap
72 option ssid OpenWrt_private
73 option hidden 0
74 option encryption none
75
76 config wifi-device wifi1
77 option type atheros
78 option channel 11
79
80 config wifi-iface
81 option device wifi1
82 # option network lan
83 option mode ap
84 option ssid OpenWrt_public
85 option hidden 1
86 option encryption none
87 \end{Verbatim}
88
89 There are two types of config sections in this file. The '\texttt{wifi-device}' refers to
90 the physical wifi interface and '\texttt{wifi-iface}' configures a virtual interface on top
91 of that (if supported by the driver).
92
93 A full outline of the wireless configuration file with description of each field:
94
95 \begin{Verbatim}
96 config wifi-device wifi device name
97 option type broadcom, atheros, mac80211
98 option country us, uk, fr, de, etc.
99 option channel 1-14
100 option maxassoc 1-128 (broadcom only)
101 option distance 1-n
102 option agmode 11b, 11g, 11a, 11bg (atheros only)
103
104 config wifi-iface
105 option network the interface you want wifi to bridge with
106 option device wifi0, wifi1, wifi2, wifiN
107 option mode ap, sta, adhoc, monitor, or wds
108 option ssid ssid name
109 option bssid bssid address
110 option encryption none, wep, psk, psk2, wpa, wpa2
111 option key encryption key
112 option key1 key 1
113 option key2 key 2
114 option key3 key 3
115 option key4 key 4
116 option server ip address
117 option port port
118 option hidden 0,1
119 option isolate 0,1
120 \end{Verbatim}
121
122 \paragraph{Options for the \texttt{wifi-device}:}
123
124 \begin{itemize}
125 \item \texttt{type} \\
126 The driver to use for this interface.
127
128 \item \texttt{country} \\
129 The country code used to determine the regulatory settings.
130
131 \item \texttt{channel} \\
132 The wifi channel (e.g. 1-14, depending on your country setting).
133
134 \item \texttt{maxassoc} \\
135 Optional: Maximum number of associated clients. This feature is supported only on the broadcom chipset.
136
137 \item \texttt{distance} \\
138 Optional: Distance between the ap and the furthest client in meters. This feature is supported only on the atheros chipset.
139
140 \item \texttt{mode} \\
141 The frequency band (\texttt{b}, \texttt{g}, \texttt{bg}, \texttt{a}). This feature is only supported on the atheros chipset.
142
143
144 \end{itemize}
145
146 \paragraph{Options for the \texttt{wifi-iface}:}
147
148 \begin{itemize}
149 \item \texttt{network} \\
150 Selects the interface section from \texttt{/etc/config/network} to be
151 used with this interface
152
153 \item \texttt{device} \\
154 Set the wifi device name.
155
156 \item \texttt{mode} \\
157 Operating mode:
158
159 \begin{itemize}
160 \item \texttt{ap} \\
161 Access point mode
162
163 \item \texttt{sta} \\
164 Client mode
165
166 \item \texttt{adhoc} \\
167 Ad-Hoc mode
168
169 \item \texttt{monitor} \\
170 Monitor mode
171
172 \item \texttt{wds} \\
173 WDS point-to-point link
174
175 \end{itemize}
176
177 \item \texttt{ssid}
178 Set the SSID to be used on the wifi device.
179
180 \item \texttt{bssid}
181 Set the BSSID address to be used for wds to set the mac address of the other wds unit.
182
183 \item \texttt{encryption} \\
184 Encryption setting. Accepts the following values:
185
186 \begin{itemize}
187 \item \texttt{none}
188 \item \texttt{wep}
189 \item \texttt{psk}, \texttt{psk2} \\
190 WPA(2) Pre-shared Key
191
192 \item \texttt{wpa}, \texttt{wpa2} \\
193 WPA(2) RADIUS
194 \end{itemize}
195
196 \item \texttt{key, key1, key2, key3, key4} (wep, wpa and psk) \\
197 WEP key, WPA key (PSK mode) or the RADIUS shared secret (WPA RADIUS mode)
198
199 \item \texttt{server} (wpa) \\
200 The RADIUS server ip address
201
202 \item \texttt{port} (wpa) \\
203 The RADIUS server port (defaults to 1812)
204
205 \item \texttt{hidden} \\
206 0 broadcasts the ssid; 1 disables broadcasting of the ssid
207
208 \item \texttt{isolate} \\
209 Optional: Isolation is a mode usually set on hotspots that limits the clients to communicate only with the AP and not with other wireless clients.
210 0 disables ap isolation (default); 1 enables ap isolation.
211
212 \end{itemize}
213
214
215 \paragraph{Limitations:}
216
217 There are certain limitations when combining modes.
218 Only the following mode combinations are supported:
219
220 \begin{itemize}
221 \item \textbf{Broadcom}: \\
222 \begin{itemize}
223 \item 1x \texttt{sta}, 0-3x \texttt{ap}
224 \item 1-4x \texttt{ap}
225 \item 1x \texttt{adhoc}
226 \item 1x \texttt{monitor}
227 \end{itemize}
228
229 WDS links can only be used in pure AP mode and cannot use WEP (except when sharing the
230 settings with the master interface, which is done automatically).
231
232 \item \textbf{Atheros}: \\
233 \begin{itemize}
234 \item 1x \texttt{sta}, 0-Nx \texttt{ap}
235 \item 1-Nx \texttt{ap}
236 \item 1x \texttt{adhoc}
237 \end{itemize}
238
239 N is the maximum number of VAPs that the module allows, it defaults to 4, but can be
240 changed by loading the module with the maxvaps=N parameter.
241 \end{itemize}
242
243 \paragraph{Adding a new driver configuration}
244
245 Since we currently only support two different wireless drivers : Broadcom and Atheros,
246 you might be interested in adding support for another driver like Ralink RT2x00,
247 Texas Instruments ACX100/111.
248
249 The driver specific script should be placed in \texttt{/lib/wifi/<driver>.sh} and has to
250 include several functions providing :
251
252 \begin{itemize}
253 \item detection of the driver presence
254 \item enabling/disabling the wifi interface(s)
255 \item configuration reading and setting
256 \item third-party programs calling (nas, supplicant)
257 \end{itemize}
258
259 Each driver script should append the driver to a global DRIVERS variable :
260
261 \begin{Verbatim}
262 append DRIVERS "driver name"
263 \end{Verbatim}
264
265 \subparagraph{\texttt{scan\_<driver>}}
266
267 This function will parse the \texttt{/etc/config/wireless} and make sure there
268 are no configuration incompatibilities, like enabling hidden SSIDS with ad-hoc mode
269 for instance. This can be more complex if your driver supports a lof of configuration
270 options. It does not change the state of the interface.
271
272 Example:
273 \begin{Verbatim}
274 scan_dummy() {
275 local device="$1"
276
277 config_get vifs "$device" vifs
278 for vif in $vifs; do
279 # check config consistency for wifi-iface sections
280 done
281 # check mode combination
282 }
283 \end{Verbatim}
284
285 \subparagraph{\texttt{enable\_<driver>}}
286
287 This function will bring up the wifi device and optionally create application specific
288 configuration files, e.g. for the WPA authenticator or supplicant.
289
290 Example:
291 \begin{Verbatim}
292 enable_dummy() {
293 local device="$1"
294
295 config_get vifs "$device" vifs
296 for vif in $vifs; do
297 # bring up virtual interface belonging to
298 # the wifi-device "$device"
299 done
300 }
301 \end{Verbatim}
302
303 \subparagraph{\texttt{disable\_<driver>}}
304
305 This function will bring down the wifi device and all its virtual interfaces (if supported).
306
307 Example:
308 \begin{Verbatim}
309 disable_dummy() {
310 local device="$1"
311
312 # bring down virtual interfaces belonging to
313 # "$device" regardless of whether they are
314 # configured or not. Don't rely on the vifs
315 # variable at this point
316 }
317 \end{Verbatim}
318
319 \subparagraph{\texttt{detect\_<driver>}}
320
321 This function looks for interfaces that are usable with the driver. Template config sections
322 for new devices should be written to stdout. Must check for already existing config sections
323 belonging to the interfaces before creating new templates.
324
325 Example:
326 \begin{Verbatim}
327 detect_dummy() {
328 [ wifi-device = "$(config_get dummydev type)" ] && return 0
329 cat <<EOF
330 config wifi-device dummydev
331 option type dummy
332 # REMOVE THIS LINE TO ENABLE WIFI:
333 option disabled 1
334
335 config wifi-iface
336 option device dummydev
337 option mode ap
338 option ssid OpenWrt
339 EOF
340 }
341 \end{Verbatim}