1wpa_supplicant and Hotspot 2.0 2============================== 3 4This document describe how the IEEE 802.11u Interworking and Wi-Fi 5Hotspot 2.0 (Release 1) implementation in wpa_supplicant can be 6configured and how an external component on the client e.g., management 7GUI or Wi-Fi framework) is used to manage this functionality. 8 9 10Introduction to Wi-Fi Hotspot 2.0 11--------------------------------- 12 13Hotspot 2.0 is the name of the Wi-Fi Alliance specification that is used 14in the Wi-Fi CERTIFIED Passpoint<TM> program. More information about 15this is available in this white paper: 16 17http://www.wi-fi.org/knowledge-center/white-papers/wi-fi-certified-passpoint%E2%84%A2-new-program-wi-fi-alliance%C2%AE-enable-seamless 18 19The Hotspot 2.0 specification is also available from WFA: 20https://www.wi-fi.org/knowledge-center/published-specifications 21 22The core Interworking functionality (network selection, GAS/ANQP) were 23standardized in IEEE Std 802.11u-2011 which is now part of the IEEE Std 24802.11-2012. 25 26 27wpa_supplicant network selection 28-------------------------------- 29 30Interworking support added option for configuring credentials that can 31work with multiple networks as an alternative to configuration of 32network blocks (e.g., per-SSID parameters). When requested to perform 33network selection, wpa_supplicant picks the highest priority enabled 34network block or credential. If a credential is picked (based on ANQP 35information from APs), a temporary network block is created 36automatically for the matching network. This temporary network block is 37used similarly to the network blocks that can be configured by the user, 38but it is not stored into the configuration file and is meant to be used 39only for temporary period of time since a new one can be created 40whenever needed based on ANQP information and the credential. 41 42By default, wpa_supplicant is not using automatic network selection 43unless requested explicitly with the interworking_select command. This 44can be changed with the auto_interworking=1 parameter to perform network 45selection automatically whenever trying to find a network for connection 46and none of the enabled network blocks match with the scan results. This 47case works similarly to "interworking_select auto", i.e., wpa_supplicant 48will internally determine which network or credential is going to be 49used based on configured priorities, scan results, and ANQP information. 50 51 52wpa_supplicant configuration 53---------------------------- 54 55Interworking and Hotspot 2.0 functionality are optional components that 56need to be enabled in the wpa_supplicant build configuration 57(.config). This is done by adding following parameters into that file: 58 59CONFIG_INTERWORKING=y 60CONFIG_HS20=y 61 62It should be noted that this functionality requires a driver that 63supports GAS/ANQP operations. This uses the same design as P2P, i.e., 64Action frame processing and building in user space within 65wpa_supplicant. The Linux nl80211 driver interface provides the needed 66functionality for this. 67 68 69There are number of run-time configuration parameters (e.g., in 70wpa_supplicant.conf when using the configuration file) that can be used 71to control Hotspot 2.0 operations. 72 73# Enable Interworking 74interworking=1 75 76# Enable Hotspot 2.0 77hs20=1 78 79# Parameters for controlling scanning 80 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 84# is enabled. 85#hessid=00:11:22:33:44:55 86 87# Access Network Type 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 92 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 99#auto_interworking=0 100 101 102Credentials can be pre-configured for automatic network selection: 103 104# credential block 105# 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. 109# 110# credential fields: 111# 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. 119# 120# pcsc: Use PC/SC and SIM/USIM card 121# 122# realm: Home Realm for Interworking 123# 124# username: Username for Interworking network selection 125# 126# password: Password for Interworking network selection 127# 128# ca_cert: CA certificate for Interworking network selection 129# 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. 135# 136# Alternatively, a named configuration blob can be used by setting 137# this to blob://blob_name. 138# 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 144# in the background. 145# 146# Windows certificate store can be used by leaving client_cert out and 147# configuring private_key in one of the following formats: 148# 149# cert://substring_to_match 150# 151# hash://certificate_thumbprint_in_hex 152# 153# For example: private_key="hash://63093aa9c47f56ae88334c7b65a4" 154# 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. 158# 159# Alternatively, a named configuration blob can be used by setting 160# this to blob://blob_name. 161# 162# private_key_passwd: Password for private key file 163# 164# imsi: IMSI in <MCC> | <MNC> | '-' | <MSIN> format 165# 166# milenage: Milenage parameters for SIM/USIM simulator in <Ki>:<OPc>:<SQN> 167# format 168# 169# domain: Home service provider FQDN 170# This is used to compare against the Domain Name List to figure out 171# whether the AP is operated by the Home SP. 172# 173# roaming_consortium: Roaming Consortium OI 174# If roaming_consortium_len is non-zero, this field contains the 175# Roaming Consortium OI that can be used to determine which access 176# points support authentication with this credential. This is an 177# alternative to the use of the realm parameter. When using Roaming 178# Consortium to match the network, the EAP parameters need to be 179# pre-configured with the credential since the NAI Realm information 180# may not be available or fetched. 181# 182# eap: Pre-configured EAP method 183# This optional field can be used to specify which EAP method will be 184# used with this credential. If not set, the EAP method is selected 185# automatically based on ANQP information (e.g., NAI Realm). 186# 187# phase1: Pre-configure Phase 1 (outer authentication) parameters 188# This optional field is used with like the 'eap' parameter. 189# 190# phase2: Pre-configure Phase 2 (inner authentication) parameters 191# This optional field is used with like the 'eap' parameter. 192# 193# excluded_ssid: Excluded SSID 194# This optional field can be used to excluded specific SSID(s) from 195# matching with the network. Multiple entries can be used to specify more 196# than one SSID. 197# 198# for example: 199# 200#cred={ 201# realm="example.com" 202# username="user@example.com" 203# password="password" 204# ca_cert="/etc/wpa_supplicant/ca.pem" 205# domain="example.com" 206#} 207# 208#cred={ 209# imsi="310026-000000000" 210# milenage="90dca4eda45b53cf0f12d7c9c3bc6a89:cb9cccc4b9258e6dca4760379fb82" 211#} 212# 213#cred={ 214# realm="example.com" 215# username="user" 216# password="password" 217# ca_cert="/etc/wpa_supplicant/ca.pem" 218# domain="example.com" 219# roaming_consortium=223344 220# eap=TTLS 221# phase2="auth=MSCHAPV2" 222#} 223 224 225Control interface 226----------------- 227 228wpa_supplicant provides a control interface that can be used from 229external programs to manage various operations. The included command 230line tool, wpa_cli, can be used for manual testing with this interface. 231 232Following wpa_cli interactive mode commands show some examples of manual 233operations related to Hotspot 2.0: 234 235Remove configured networks and credentials: 236 237> remove_network all 238OK 239> remove_cred all 240OK 241 242 243Add a username/password credential: 244 245> add_cred 2460 247> set_cred 0 realm "mail.example.com" 248OK 249> set_cred 0 username "username" 250OK 251> set_cred 0 password "password" 252OK 253> set_cred 0 priority 1 254OK 255 256Add a SIM credential using a simulated SIM/USIM card for testing: 257 258> add_cred 2591 260> set_cred 1 imsi "23456-0000000000" 261OK 262> set_cred 1 milenage "90dca4eda45b53cf0f12d7c9c3bc6a89:cb9cccc4b9258e6dca4760379fb82581:000000000123" 263OK 264> set_cred 1 priority 1 265OK 266 267Note: the return value of add_cred is used as the first argument to 268the following set_cred commands. 269 270 271Add a WPA2-Enterprise network: 272 273> add_network 2740 275> set_network 0 key_mgmt WPA-EAP 276OK 277> set_network 0 ssid "enterprise" 278OK 279> set_network 0 eap TTLS 280OK 281> set_network 0 anonymous_identity "anonymous" 282OK 283> set_network 0 identity "user" 284OK 285> set_network 0 password "password" 286OK 287> set_network 0 priority 0 288OK 289> enable_network 0 no-connect 290OK 291 292 293Add an open network: 294 295> add_network 2963 297> set_network 3 key_mgmt NONE 298OK 299> set_network 3 ssid "coffee-shop" 300OK 301> select_network 3 302OK 303 304Note: the return value of add_network is used as the first argument to 305the following set_network commands. 306 307The preferred credentials/networks can be indicated with the priority 308parameter (1 is higher priority than 0). 309 310 311Interworking network selection can be started with interworking_select 312command. This instructs wpa_supplicant to run a network scan and iterate 313through the discovered APs to request ANQP information from the APs that 314advertise support for Interworking/Hotspot 2.0: 315 316> interworking_select 317OK 318<3>Starting ANQP fetch for 02:00:00:00:01:00 319<3>RX-ANQP 02:00:00:00:01:00 ANQP Capability list 320<3>RX-ANQP 02:00:00:00:01:00 Roaming Consortium list 321<3>RX-HS20-ANQP 02:00:00:00:01:00 HS Capability List 322<3>ANQP fetch completed 323<3>INTERWORKING-AP 02:00:00:00:01:00 type=unknown 324 325 326INTERWORKING-AP event messages indicate the APs that support network 327selection and for which there is a matching 328credential. interworking_connect command can be used to select a network 329to connect with: 330 331 332> interworking_connect 02:00:00:00:01:00 333OK 334<3>CTRL-EVENT-SCAN-RESULTS 335<3>SME: Trying to authenticate with 02:00:00:00:01:00 (SSID='Example Network' freq=2412 MHz) 336<3>Trying to associate with 02:00:00:00:01:00 (SSID='Example Network' freq=2412 MHz) 337<3>Associated with 02:00:00:00:01:00 338<3>CTRL-EVENT-EAP-STARTED EAP authentication started 339<3>CTRL-EVENT-EAP-PROPOSED-METHOD vendor=0 method=21 340<3>CTRL-EVENT-EAP-METHOD EAP vendor 0 method 21 (TTLS) selected 341<3>CTRL-EVENT-EAP-SUCCESS EAP authentication completed successfully 342<3>WPA: Key negotiation completed with 02:00:00:00:01:00 [PTK=CCMP GTK=CCMP] 343<3>CTRL-EVENT-CONNECTED - Connection to 02:00:00:00:01:00 completed (auth) [id=0 id_str=] 344 345 346wpa_supplicant creates a temporary network block for the selected 347network based on the configured credential and ANQP information from the 348AP: 349 350> list_networks 351network id / ssid / bssid / flags 3520 Example Network any [CURRENT] 353> get_network 0 key_mgmt 354WPA-EAP 355> get_network 0 eap 356TTLS 357 358 359Alternatively to using an external program to select the network, 360"interworking_select auto" command can be used to request wpa_supplicant 361to select which network to use based on configured priorities: 362 363 364> remove_network all 365OK 366<3>CTRL-EVENT-DISCONNECTED bssid=02:00:00:00:01:00 reason=1 locally_generated=1 367> interworking_select auto 368OK 369<3>Starting ANQP fetch for 02:00:00:00:01:00 370<3>RX-ANQP 02:00:00:00:01:00 ANQP Capability list 371<3>RX-ANQP 02:00:00:00:01:00 Roaming Consortium list 372<3>RX-HS20-ANQP 02:00:00:00:01:00 HS Capability List 373<3>ANQP fetch completed 374<3>INTERWORKING-AP 02:00:00:00:01:00 type=unknown 375<3>CTRL-EVENT-SCAN-RESULTS 376<3>SME: Trying to authenticate with 02:00:00:00:01:00 (SSID='Example Network' freq=2412 MHz) 377<3>Trying to associate with 02:00:00:00:01:00 (SSID='Example Network' freq=2412 MHz) 378<3>Associated with 02:00:00:00:01:00 379<3>CTRL-EVENT-EAP-STARTED EAP authentication started 380<3>CTRL-EVENT-EAP-PROPOSED-METHOD vendor=0 method=21 381<3>CTRL-EVENT-EAP-METHOD EAP vendor 0 method 21 (TTLS) selected 382<3>CTRL-EVENT-EAP-SUCCESS EAP authentication completed successfully 383<3>WPA: Key negotiation completed with 02:00:00:00:01:00 [PTK=CCMP GTK=CCMP] 384<3>CTRL-EVENT-CONNECTED - Connection to 02:00:00:00:01:00 completed (reauth) [id=0 id_str=] 385 386 387The connection status can be shown with the status command: 388 389> status 390bssid=02:00:00:00:01:00 391ssid=Example Network 392id=0 393mode=station 394pairwise_cipher=CCMP <--- link layer security indication 395group_cipher=CCMP 396key_mgmt=WPA2/IEEE 802.1X/EAP 397wpa_state=COMPLETED 398p2p_device_address=02:00:00:00:00:00 399address=02:00:00:00:00:00 400hs20=1 <--- HS 2.0 indication 401Supplicant PAE state=AUTHENTICATED 402suppPortStatus=Authorized 403EAP state=SUCCESS 404selectedMethod=21 (EAP-TTLS) 405EAP TLS cipher=AES-128-SHA 406EAP-TTLSv0 Phase2 method=PAP 407 408 409> status 410bssid=02:00:00:00:02:00 411ssid=coffee-shop 412id=3 413mode=station 414pairwise_cipher=NONE 415group_cipher=NONE 416key_mgmt=NONE 417wpa_state=COMPLETED 418p2p_device_address=02:00:00:00:00:00 419address=02:00:00:00:00:00 420 421 422Note: The Hotspot 2.0 indication is shown as "hs20=1" in the status 423command output. Link layer security is indicated with the 424pairwise_cipher (CCMP = secure, NONE = no encryption used). 425 426 427Also the scan results include the Hotspot 2.0 indication: 428 429> scan_results 430bssid / frequency / signal level / flags / ssid 43102:00:00:00:01:00 2412 -30 [WPA2-EAP-CCMP][ESS][HS20] Example Network 432 433 434ANQP information for the BSS can be fetched using the BSS command: 435 436> bss 02:00:00:00:01:00 437id=1 438bssid=02:00:00:00:01:00 439freq=2412 440beacon_int=100 441capabilities=0x0411 442qual=0 443noise=-92 444level=-30 445tsf=1345573286517276 446age=105 447ie=000f4578616d706c65204e6574776f726b010882848b960c1218240301012a010432043048606c30140100000fac040100000fac040100000fac0100007f04000000806b091e07010203040506076c027f006f1001531122331020304050010203040506dd05506f9a1000 448flags=[WPA2-EAP-CCMP][ESS][HS20] 449ssid=Example Network 450anqp_roaming_consortium=031122330510203040500601020304050603fedcba 451 452 453ANQP queries can also be requested with the anqp_get and hs20_anqp_get 454commands: 455 456> anqp_get 02:00:00:00:01:00 261 457OK 458<3>RX-ANQP 02:00:00:00:01:00 Roaming Consortium list 459> hs20_anqp_get 02:00:00:00:01:00 2 460OK 461<3>RX-HS20-ANQP 02:00:00:00:01:00 HS Capability List 462 463In addition, fetch_anqp command can be used to request similar set of 464ANQP queries to be done as is run as part of interworking_select: 465 466> scan 467OK 468<3>CTRL-EVENT-SCAN-RESULTS 469> fetch_anqp 470OK 471<3>Starting ANQP fetch for 02:00:00:00:01:00 472<3>RX-ANQP 02:00:00:00:01:00 ANQP Capability list 473<3>RX-ANQP 02:00:00:00:01:00 Roaming Consortium list 474<3>RX-HS20-ANQP 02:00:00:00:01:00 HS Capability List 475<3>ANQP fetch completed 476