wireless.tex: update docs to reflect txpower move
[openwrt/staging/yousong.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 hwmode "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 hwmode 11b, 11g, 11a, 11bg (atheros, mac80211)
103 option rxantenna 0,1,2 (atheros, broadcom)
104 option txantenna 0,1,2 (atheros, broadcom)
105 option txpower transmission power in dBm
106
107 config wifi-iface
108 option network the interface you want wifi to bridge with
109 option device wifi0, wifi1, wifi2, wifiN
110 option mode ap, sta, adhoc, monitor, or wds
111 option txpower (deprecated) transmission power in dBm
112 option ssid ssid name
113 option bssid bssid address
114 option encryption none, wep, psk, psk2, wpa, wpa2
115 option key encryption key
116 option key1 key 1
117 option key2 key 2
118 option key3 key 3
119 option key4 key 4
120 option server ip address
121 option port port
122 option hidden 0,1
123 option isolate 0,1
124 \end{Verbatim}
125
126 \paragraph{Options for the \texttt{wifi-device}:}
127
128 \begin{itemize}
129 \item \texttt{type} \\
130 The driver to use for this interface.
131
132 \item \texttt{country} \\
133 The country code used to determine the regulatory settings.
134
135 \item \texttt{channel} \\
136 The wifi channel (e.g. 1-14, depending on your country setting).
137
138 \item \texttt{maxassoc} \\
139 Optional: Maximum number of associated clients. This feature is supported only on the broadcom chipset.
140
141 \item \texttt{distance} \\
142 Optional: Distance between the ap and the furthest client in meters. This feature is supported only on the atheros chipset.
143
144 \item \texttt{mode} \\
145 The frequency band (\texttt{b}, \texttt{g}, \texttt{bg}, \texttt{a}). This feature is only supported on the atheros chipset.
146
147 \item \texttt{diversity} \\
148 Optional: Enable diversity for the Wi-Fi device. This feature is supported only on the atheros chipset.
149
150 \item \texttt{rxantenna} \\
151 Optional: Antenna identifier (0, 1 or 2) for reception. This feature is supported by atheros and some broadcom chipsets.
152
153 \item \texttt{txantenna} \\
154 Optional: Antenna identifier (0, 1 or 2) for emission. This feature is supported by atheros and some broadcom chipsets.
155
156 \item \texttt{txpower}
157 Set the transmission power to be used. The amount is specified in dBm.
158
159 \end{itemize}
160
161 \paragraph{Options for the \texttt{wifi-iface}:}
162
163 \begin{itemize}
164 \item \texttt{network} \\
165 Selects the interface section from \texttt{/etc/config/network} to be
166 used with this interface
167
168 \item \texttt{device} \\
169 Set the wifi device name.
170
171 \item \texttt{mode} \\
172 Operating mode:
173
174 \begin{itemize}
175 \item \texttt{ap} \\
176 Access point mode
177
178 \item \texttt{sta} \\
179 Client mode
180
181 \item \texttt{adhoc} \\
182 Ad-Hoc mode
183
184 \item \texttt{monitor} \\
185 Monitor mode
186
187 \item \texttt{wds} \\
188 WDS point-to-point link
189
190 \end{itemize}
191
192 \item \texttt{ssid}
193 Set the SSID to be used on the wifi device.
194
195 \item \texttt{bssid}
196 Set the BSSID address to be used for wds to set the mac address of the other wds unit.
197
198 \item \texttt{txpower}
199 (Deprecated, set in wifi-device) Set the transmission power to be used. The amount is specified in dBm.
200
201 \item \texttt{encryption} \\
202 Encryption setting. Accepts the following values:
203
204 \begin{itemize}
205 \item \texttt{none}
206 \item \texttt{wep}
207 \item \texttt{psk}, \texttt{psk2} \\
208 WPA(2) Pre-shared Key
209
210 \item \texttt{wpa}, \texttt{wpa2} \\
211 WPA(2) RADIUS
212 \end{itemize}
213
214 \item \texttt{key, key1, key2, key3, key4} (wep, wpa and psk) \\
215 WEP key, WPA key (PSK mode) or the RADIUS shared secret (WPA RADIUS mode)
216
217 \item \texttt{server} (wpa) \\
218 The RADIUS server ip address
219
220 \item \texttt{port} (wpa) \\
221 The RADIUS server port (defaults to 1812)
222
223 \item \texttt{hidden} \\
224 0 broadcasts the ssid; 1 disables broadcasting of the ssid
225
226 \item \texttt{isolate} \\
227 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.
228 0 disables ap isolation (default); 1 enables ap isolation.
229
230 \end{itemize}
231
232 \paragraph{Wireless Distribution System}
233
234 WDS is a non-standard mode which will be working between two Broadcom devices for instance
235 but not between a Broadcom and Atheros device.
236
237 \subparagraph{Unencrypted WDS connections}
238
239 This configuration example shows you how to setup unencrypted WDS connections.
240 We assume that the peer configured as below as the BSSID ca:fe:ba:be:00:01
241 and the remote WDS endpoint ca:fe:ba:be:00:02 (option bssid field).
242
243 \begin{Verbatim}
244 config wifi-device "wl0"
245 option type "broadcom"
246 option channel "5"
247
248 config wifi-iface
249 option device "wl0"
250 option network lan
251 option mode "ap"
252 option ssid "OpenWrt"
253 option hidden "0"
254 option encryption "none"
255
256 config wifi-iface
257 option device "wl0"
258 option network lan
259 option mode wds
260 option ssid "OpenWrt WDS"
261 option bssid "ca:fe:ba:be:00:02"
262 \end{Verbatim}
263
264 \subparagraph{Encrypted WDS connections}
265
266 It is also possible to encrypt WDS connections. \texttt{psk}, \texttt{psk2} and
267 \texttt{psk+psk2} modes are supported. Configuration below is an example
268 configuration using Pre-Shared-Keys with AES algorithm.
269
270 \begin{Verbatim}
271 config wifi-device wl0
272 option type broadcom
273 option channel 5
274
275 config wifi-iface
276 option device "wl0"
277 option network lan
278 option mode ap
279 option ssid "OpenWrt"
280 option encryption psk2
281 option key "<key for clients>"
282
283 config wifi-iface
284 option device "wl0"
285 option network lan
286 option mode wds
287 option bssid ca:fe:ba:be:00:02
288 option ssid "OpenWrt WDS"
289 option encryption psk2
290 option key "<psk for WDS>"
291 \end{Verbatim}
292
293 \paragraph{802.1x configurations}
294
295 OpenWrt supports both 802.1x client and Access Point
296 configurations. 802.1x client is only working with
297 Atheros or mac80211 drivers. Configuration only
298 supports EAP types TLS, TTLS or PEAP.
299
300 \subparagraph{EAP-TLS}
301
302 \begin{Verbatim}
303 config wifi-iface
304 option device "ath0"
305 option network lan
306 option ssid OpenWrt
307 option eap_type tls
308 option ca_cert "/etc/config/certs/ca.crt"
309 option priv_key "/etc/config/certs/priv.crt"
310 option priv_key_pwd "PKCS#12 passphrase"
311 \end{Verbatim}
312
313 \subparagraph{EAP-PEAP}
314
315 \begin{Verbatim}
316 config wifi-iface
317 option device "ath0"
318 option network lan
319 option ssid OpenWrt
320 option eap_type peap
321 option ca_cert "/etc/config/certs/ca.crt"
322 option auth MSCHAPV2
323 option identity username
324 option password password
325 \end{Verbatim}
326
327 \paragraph{Limitations:}
328
329 There are certain limitations when combining modes.
330 Only the following mode combinations are supported:
331
332 \begin{itemize}
333 \item \textbf{Broadcom}: \\
334 \begin{itemize}
335 \item 1x \texttt{sta}, 0-3x \texttt{ap}
336 \item 1-4x \texttt{ap}
337 \item 1x \texttt{adhoc}
338 \item 1x \texttt{monitor}
339 \end{itemize}
340
341 WDS links can only be used in pure AP mode and cannot use WEP (except when sharing the
342 settings with the master interface, which is done automatically).
343
344 \item \textbf{Atheros}: \\
345 \begin{itemize}
346 \item 1x \texttt{sta}, 0-Nx \texttt{ap}
347 \item 1-Nx \texttt{ap}
348 \item 1x \texttt{adhoc}
349 \end{itemize}
350
351 N is the maximum number of VAPs that the module allows, it defaults to 4, but can be
352 changed by loading the module with the maxvaps=N parameter.
353 \end{itemize}
354
355 \paragraph{Adding a new driver configuration}
356
357 Since we currently only support thread different wireless drivers : Broadcom, Atheros and mac80211,
358 you might be interested in adding support for another driver like Ralink RT2x00,
359 Texas Instruments ACX100/111.
360
361 The driver specific script should be placed in \texttt{/lib/wifi/<driver>.sh} and has to
362 include several functions providing :
363
364 \begin{itemize}
365 \item detection of the driver presence
366 \item enabling/disabling the wifi interface(s)
367 \item configuration reading and setting
368 \item third-party programs calling (nas, supplicant)
369 \end{itemize}
370
371 Each driver script should append the driver to a global DRIVERS variable :
372
373 \begin{Verbatim}
374 append DRIVERS "driver name"
375 \end{Verbatim}
376
377 \subparagraph{\texttt{scan\_<driver>}}
378
379 This function will parse the \texttt{/etc/config/wireless} and make sure there
380 are no configuration incompatibilities, like enabling hidden SSIDS with ad-hoc mode
381 for instance. This can be more complex if your driver supports a lof of configuration
382 options. It does not change the state of the interface.
383
384 Example:
385 \begin{Verbatim}
386 scan_dummy() {
387 local device="$1"
388
389 config_get vifs "$device" vifs
390 for vif in $vifs; do
391 # check config consistency for wifi-iface sections
392 done
393 # check mode combination
394 }
395 \end{Verbatim}
396
397 \subparagraph{\texttt{enable\_<driver>}}
398
399 This function will bring up the wifi device and optionally create application specific
400 configuration files, e.g. for the WPA authenticator or supplicant.
401
402 Example:
403 \begin{Verbatim}
404 enable_dummy() {
405 local device="$1"
406
407 config_get vifs "$device" vifs
408 for vif in $vifs; do
409 # bring up virtual interface belonging to
410 # the wifi-device "$device"
411 done
412 }
413 \end{Verbatim}
414
415 \subparagraph{\texttt{disable\_<driver>}}
416
417 This function will bring down the wifi device and all its virtual interfaces (if supported).
418
419 Example:
420 \begin{Verbatim}
421 disable_dummy() {
422 local device="$1"
423
424 # bring down virtual interfaces belonging to
425 # "$device" regardless of whether they are
426 # configured or not. Don't rely on the vifs
427 # variable at this point
428 }
429 \end{Verbatim}
430
431 \subparagraph{\texttt{detect\_<driver>}}
432
433 This function looks for interfaces that are usable with the driver. Template config sections
434 for new devices should be written to stdout. Must check for already existing config sections
435 belonging to the interfaces before creating new templates.
436
437 Example:
438 \begin{Verbatim}
439 detect_dummy() {
440 [ wifi-device = "$(config_get dummydev type)" ] && return 0
441 cat <<EOF
442 config wifi-device dummydev
443 option type dummy
444 # REMOVE THIS LINE TO ENABLE WIFI:
445 option disabled 1
446
447 config wifi-iface
448 option device dummydev
449 option mode ap
450 option ssid OpenWrt
451 EOF
452 }
453 \end{Verbatim}