1 wpa_supplicant and Hotspot 2.0
2 ==============================
4 This document describe how the IEEE 802.11u Interworking and Wi-Fi
5 Hotspot 2.0 (Release 1) implementation in wpa_supplicant can be
6 configured and how an external component on the client e.g., management
7 GUI or Wi-Fi framework) is used to manage this functionality.
10 Introduction to Wi-Fi Hotspot 2.0
11 ---------------------------------
13 Hotspot 2.0 is the name of the Wi-Fi Alliance specification that is used
14 in the Wi-Fi CERTIFIED Passpoint<TM> program. More information about
15 this is available in this white paper:
17 http://www.wi-fi.org/knowledge-center/white-papers/wi-fi-certified-passpoint%E2%84%A2-new-program-wi-fi-alliance%C2%AE-enable-seamless
19 The Hotspot 2.0 specification is also available from WFA:
20 https://www.wi-fi.org/knowledge-center/published-specifications
22 The core Interworking functionality (network selection, GAS/ANQP) were
23 standardized in IEEE Std 802.11u-2011 which is now part of the IEEE Std
27 wpa_supplicant network selection
28 --------------------------------
30 Interworking support added option for configuring credentials that can
31 work with multiple networks as an alternative to configuration of
32 network blocks (e.g., per-SSID parameters). When requested to perform
33 network selection, wpa_supplicant picks the highest priority enabled
34 network block or credential. If a credential is picked (based on ANQP
35 information from APs), a temporary network block is created
36 automatically for the matching network. This temporary network block is
37 used similarly to the network blocks that can be configured by the user,
38 but it is not stored into the configuration file and is meant to be used
39 only for temporary period of time since a new one can be created
40 whenever needed based on ANQP information and the credential.
42 By default, wpa_supplicant is not using automatic network selection
43 unless requested explicitly with the interworking_select command. This
44 can be changed with the auto_interworking=1 parameter to perform network
45 selection automatically whenever trying to find a network for connection
46 and none of the enabled network blocks match with the scan results. This
47 case works similarly to "interworking_select auto", i.e., wpa_supplicant
48 will internally determine which network or credential is going to be
49 used based on configured priorities, scan results, and ANQP information.
52 wpa_supplicant configuration
53 ----------------------------
55 Interworking and Hotspot 2.0 functionality are optional components that
56 need to be enabled in the wpa_supplicant build configuration
57 (.config). This is done by adding following parameters into that file:
62 It should be noted that this functionality requires a driver that
63 supports GAS/ANQP operations. This uses the same design as P2P, i.e.,
64 Action frame processing and building in user space within
65 wpa_supplicant. The Linux nl80211 driver interface provides the needed
66 functionality for this.
69 There are number of run-time configuration parameters (e.g., in
70 wpa_supplicant.conf when using the configuration file) that can be used
71 to control Hotspot 2.0 operations.
79 # Parameters for controlling scanning
81 # Homogenous ESS identifier
82 # If this is set, scans will be used to request response only from BSSes
83 # belonging to the specified Homogeneous ESS. This is used only if interworking
85 #hessid=00:11:22:33:44:55
88 # When Interworking is enabled, scans can be limited to APs that advertise the
89 # specified Access Network Type (0..15; with 15 indicating wildcard match).
90 # This value controls the Access Network Type value in Probe Request frames.
91 #access_network_type=15
93 # Automatic network selection behavior
94 # 0 = do not automatically go through Interworking network selection
95 # (i.e., require explicit interworking_select command for this; default)
96 # 1 = perform Interworking network selection if one or more
97 # credentials have been configured and scan did not find a
98 # matching network block
102 Credentials can be pre-configured for automatic network selection:
106 # Each credential used for automatic network selection is configured as a set
107 # of parameters that are compared to the information advertised by the APs when
108 # interworking_select and interworking_connect commands are used.
112 # priority: Priority group
113 # By default, all networks and credentials get the same priority group
114 # (0). This field can be used to give higher priority for credentials
115 # (and similarly in struct wpa_ssid for network blocks) to change the
116 # Interworking automatic networking selection behavior. The matching
117 # network (based on either an enabled network block or a credential)
118 # with the highest priority value will be selected.
120 # pcsc: Use PC/SC and SIM/USIM card
122 # realm: Home Realm for Interworking
124 # username: Username for Interworking network selection
126 # password: Password for Interworking network selection
128 # ca_cert: CA certificate for Interworking network selection
130 # client_cert: File path to client certificate file (PEM/DER)
131 # This field is used with Interworking networking selection for a case
132 # where client certificate/private key is used for authentication
133 # (EAP-TLS). Full path to the file should be used since working
134 # directory may change when wpa_supplicant is run in the background.
136 # Alternatively, a named configuration blob can be used by setting
137 # this to blob://blob_name.
139 # private_key: File path to client private key file (PEM/DER/PFX)
140 # When PKCS#12/PFX file (.p12/.pfx) is used, client_cert should be
141 # commented out. Both the private key and certificate will be read
142 # from the PKCS#12 file in this case. Full path to the file should be
143 # used since working directory may change when wpa_supplicant is run
146 # Windows certificate store can be used by leaving client_cert out and
147 # configuring private_key in one of the following formats:
149 # cert://substring_to_match
151 # hash://certificate_thumbprint_in_hex
153 # For example: private_key="hash://63093aa9c47f56ae88334c7b65a4"
155 # Note that when running wpa_supplicant as an application, the user
156 # certificate store (My user account) is used, whereas computer store
157 # (Computer account) is used when running wpasvc as a service.
159 # Alternatively, a named configuration blob can be used by setting
160 # this to blob://blob_name.
162 # private_key_passwd: Password for private key file
164 # imsi: IMSI in <MCC> | <MNC> | '-' | <MSIN> format
166 # milenage: Milenage parameters for SIM/USIM simulator in <Ki>:<OPc>:<SQN>
169 # domain: Home service provider FQDN(s)
170 # This is used to compare against the Domain Name List to figure out
171 # whether the AP is operated by the Home SP. Multiple domain entries can
172 # be used to configure alternative FQDNs that will be considered home
175 # roaming_consortium: Roaming Consortium OI
176 # If roaming_consortium_len is non-zero, this field contains the
177 # Roaming Consortium OI that can be used to determine which access
178 # points support authentication with this credential. This is an
179 # alternative to the use of the realm parameter. When using Roaming
180 # Consortium to match the network, the EAP parameters need to be
181 # pre-configured with the credential since the NAI Realm information
182 # may not be available or fetched.
184 # eap: Pre-configured EAP method
185 # This optional field can be used to specify which EAP method will be
186 # used with this credential. If not set, the EAP method is selected
187 # automatically based on ANQP information (e.g., NAI Realm).
189 # phase1: Pre-configure Phase 1 (outer authentication) parameters
190 # This optional field is used with like the 'eap' parameter.
192 # phase2: Pre-configure Phase 2 (inner authentication) parameters
193 # This optional field is used with like the 'eap' parameter.
195 # excluded_ssid: Excluded SSID
196 # This optional field can be used to excluded specific SSID(s) from
197 # matching with the network. Multiple entries can be used to specify more
203 # realm="example.com"
204 # username="user@example.com"
205 # password="password"
206 # ca_cert="/etc/wpa_supplicant/ca.pem"
207 # domain="example.com"
211 # imsi="310026-000000000"
212 # milenage="90dca4eda45b53cf0f12d7c9c3bc6a89:cb9cccc4b9258e6dca4760379fb82"
216 # realm="example.com"
218 # password="password"
219 # ca_cert="/etc/wpa_supplicant/ca.pem"
220 # domain="example.com"
221 # roaming_consortium=223344
223 # phase2="auth=MSCHAPV2"
230 wpa_supplicant provides a control interface that can be used from
231 external programs to manage various operations. The included command
232 line tool, wpa_cli, can be used for manual testing with this interface.
234 Following wpa_cli interactive mode commands show some examples of manual
235 operations related to Hotspot 2.0:
237 Remove configured networks and credentials:
245 Add a username/password credential:
249 > set_cred 0 realm "mail.example.com"
251 > set_cred 0 username "username"
253 > set_cred 0 password "password"
255 > set_cred 0 priority 1
258 Add a SIM credential using a simulated SIM/USIM card for testing:
262 > set_cred 1 imsi "23456-0000000000"
264 > set_cred 1 milenage "90dca4eda45b53cf0f12d7c9c3bc6a89:cb9cccc4b9258e6dca4760379fb82581:000000000123"
266 > set_cred 1 priority 1
269 Note: the return value of add_cred is used as the first argument to
270 the following set_cred commands.
273 Add a WPA2-Enterprise network:
277 > set_network 0 key_mgmt WPA-EAP
279 > set_network 0 ssid "enterprise"
281 > set_network 0 eap TTLS
283 > set_network 0 anonymous_identity "anonymous"
285 > set_network 0 identity "user"
287 > set_network 0 password "password"
289 > set_network 0 priority 0
291 > enable_network 0 no-connect
299 > set_network 3 key_mgmt NONE
301 > set_network 3 ssid "coffee-shop"
306 Note: the return value of add_network is used as the first argument to
307 the following set_network commands.
309 The preferred credentials/networks can be indicated with the priority
310 parameter (1 is higher priority than 0).
313 Interworking network selection can be started with interworking_select
314 command. This instructs wpa_supplicant to run a network scan and iterate
315 through the discovered APs to request ANQP information from the APs that
316 advertise support for Interworking/Hotspot 2.0:
318 > interworking_select
320 <3>Starting ANQP fetch for 02:00:00:00:01:00
321 <3>RX-ANQP 02:00:00:00:01:00 ANQP Capability list
322 <3>RX-ANQP 02:00:00:00:01:00 Roaming Consortium list
323 <3>RX-HS20-ANQP 02:00:00:00:01:00 HS Capability List
324 <3>ANQP fetch completed
325 <3>INTERWORKING-AP 02:00:00:00:01:00 type=unknown
328 INTERWORKING-AP event messages indicate the APs that support network
329 selection and for which there is a matching
330 credential. interworking_connect command can be used to select a network
334 > interworking_connect 02:00:00:00:01:00
336 <3>CTRL-EVENT-SCAN-RESULTS
337 <3>SME: Trying to authenticate with 02:00:00:00:01:00 (SSID='Example Network' freq=2412 MHz)
338 <3>Trying to associate with 02:00:00:00:01:00 (SSID='Example Network' freq=2412 MHz)
339 <3>Associated with 02:00:00:00:01:00
340 <3>CTRL-EVENT-EAP-STARTED EAP authentication started
341 <3>CTRL-EVENT-EAP-PROPOSED-METHOD vendor=0 method=21
342 <3>CTRL-EVENT-EAP-METHOD EAP vendor 0 method 21 (TTLS) selected
343 <3>CTRL-EVENT-EAP-SUCCESS EAP authentication completed successfully
344 <3>WPA: Key negotiation completed with 02:00:00:00:01:00 [PTK=CCMP GTK=CCMP]
345 <3>CTRL-EVENT-CONNECTED - Connection to 02:00:00:00:01:00 completed (auth) [id=0 id_str=]
348 wpa_supplicant creates a temporary network block for the selected
349 network based on the configured credential and ANQP information from the
353 network id / ssid / bssid / flags
354 0 Example Network any [CURRENT]
355 > get_network 0 key_mgmt
361 Alternatively to using an external program to select the network,
362 "interworking_select auto" command can be used to request wpa_supplicant
363 to select which network to use based on configured priorities:
368 <3>CTRL-EVENT-DISCONNECTED bssid=02:00:00:00:01:00 reason=1 locally_generated=1
369 > interworking_select auto
371 <3>Starting ANQP fetch for 02:00:00:00:01:00
372 <3>RX-ANQP 02:00:00:00:01:00 ANQP Capability list
373 <3>RX-ANQP 02:00:00:00:01:00 Roaming Consortium list
374 <3>RX-HS20-ANQP 02:00:00:00:01:00 HS Capability List
375 <3>ANQP fetch completed
376 <3>INTERWORKING-AP 02:00:00:00:01:00 type=unknown
377 <3>CTRL-EVENT-SCAN-RESULTS
378 <3>SME: Trying to authenticate with 02:00:00:00:01:00 (SSID='Example Network' freq=2412 MHz)
379 <3>Trying to associate with 02:00:00:00:01:00 (SSID='Example Network' freq=2412 MHz)
380 <3>Associated with 02:00:00:00:01:00
381 <3>CTRL-EVENT-EAP-STARTED EAP authentication started
382 <3>CTRL-EVENT-EAP-PROPOSED-METHOD vendor=0 method=21
383 <3>CTRL-EVENT-EAP-METHOD EAP vendor 0 method 21 (TTLS) selected
384 <3>CTRL-EVENT-EAP-SUCCESS EAP authentication completed successfully
385 <3>WPA: Key negotiation completed with 02:00:00:00:01:00 [PTK=CCMP GTK=CCMP]
386 <3>CTRL-EVENT-CONNECTED - Connection to 02:00:00:00:01:00 completed (reauth) [id=0 id_str=]
389 The connection status can be shown with the status command:
392 bssid=02:00:00:00:01:00
396 pairwise_cipher=CCMP <--- link layer security indication
398 key_mgmt=WPA2/IEEE 802.1X/EAP
400 p2p_device_address=02:00:00:00:00:00
401 address=02:00:00:00:00:00
402 hs20=1 <--- HS 2.0 indication
403 Supplicant PAE state=AUTHENTICATED
404 suppPortStatus=Authorized
406 selectedMethod=21 (EAP-TTLS)
407 EAP TLS cipher=AES-128-SHA
408 EAP-TTLSv0 Phase2 method=PAP
412 bssid=02:00:00:00:02:00
420 p2p_device_address=02:00:00:00:00:00
421 address=02:00:00:00:00:00
424 Note: The Hotspot 2.0 indication is shown as "hs20=1" in the status
425 command output. Link layer security is indicated with the
426 pairwise_cipher (CCMP = secure, NONE = no encryption used).
429 Also the scan results include the Hotspot 2.0 indication:
432 bssid / frequency / signal level / flags / ssid
433 02:00:00:00:01:00 2412 -30 [WPA2-EAP-CCMP][ESS][HS20] Example Network
436 ANQP information for the BSS can be fetched using the BSS command:
438 > bss 02:00:00:00:01:00
440 bssid=02:00:00:00:01:00
449 ie=000f4578616d706c65204e6574776f726b010882848b960c1218240301012a010432043048606c30140100000fac040100000fac040100000fac0100007f04000000806b091e07010203040506076c027f006f1001531122331020304050010203040506dd05506f9a1000
450 flags=[WPA2-EAP-CCMP][ESS][HS20]
452 anqp_roaming_consortium=031122330510203040500601020304050603fedcba
455 ANQP queries can also be requested with the anqp_get and hs20_anqp_get
458 > anqp_get 02:00:00:00:01:00 261
460 <3>RX-ANQP 02:00:00:00:01:00 Roaming Consortium list
461 > hs20_anqp_get 02:00:00:00:01:00 2
463 <3>RX-HS20-ANQP 02:00:00:00:01:00 HS Capability List
465 In addition, fetch_anqp command can be used to request similar set of
466 ANQP queries to be done as is run as part of interworking_select:
470 <3>CTRL-EVENT-SCAN-RESULTS
473 <3>Starting ANQP fetch for 02:00:00:00:01:00
474 <3>RX-ANQP 02:00:00:00:01:00 ANQP Capability list
475 <3>RX-ANQP 02:00:00:00:01:00 Roaming Consortium list
476 <3>RX-HS20-ANQP 02:00:00:00:01:00 HS Capability List
477 <3>ANQP fetch completed