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# temporary: Whether this credential is temporary and not to be saved 113# 114# priority: Priority group 115# By default, all networks and credentials get the same priority group 116# (0). This field can be used to give higher priority for credentials 117# (and similarly in struct wpa_ssid for network blocks) to change the 118# Interworking automatic networking selection behavior. The matching 119# network (based on either an enabled network block or a credential) 120# with the highest priority value will be selected. 121# 122# pcsc: Use PC/SC and SIM/USIM card 123# 124# realm: Home Realm for Interworking 125# 126# username: Username for Interworking network selection 127# 128# password: Password for Interworking network selection 129# 130# ca_cert: CA certificate for Interworking network selection 131# 132# client_cert: File path to client certificate file (PEM/DER) 133# This field is used with Interworking networking selection for a case 134# where client certificate/private key is used for authentication 135# (EAP-TLS). Full path to the file should be used since working 136# directory may change when wpa_supplicant is run in the background. 137# 138# Alternatively, a named configuration blob can be used by setting 139# this to blob://blob_name. 140# 141# private_key: File path to client private key file (PEM/DER/PFX) 142# When PKCS#12/PFX file (.p12/.pfx) is used, client_cert should be 143# commented out. Both the private key and certificate will be read 144# from the PKCS#12 file in this case. Full path to the file should be 145# used since working directory may change when wpa_supplicant is run 146# in the background. 147# 148# Windows certificate store can be used by leaving client_cert out and 149# configuring private_key in one of the following formats: 150# 151# cert://substring_to_match 152# 153# hash://certificate_thumbprint_in_hex 154# 155# For example: private_key="hash://63093aa9c47f56ae88334c7b65a4" 156# 157# Note that when running wpa_supplicant as an application, the user 158# certificate store (My user account) is used, whereas computer store 159# (Computer account) is used when running wpasvc as a service. 160# 161# Alternatively, a named configuration blob can be used by setting 162# this to blob://blob_name. 163# 164# private_key_passwd: Password for private key file 165# 166# imsi: IMSI in <MCC> | <MNC> | '-' | <MSIN> format 167# 168# milenage: Milenage parameters for SIM/USIM simulator in <Ki>:<OPc>:<SQN> 169# format 170# 171# domain_suffix_match: Constraint for server domain name 172# If set, this FQDN is used as a suffix match requirement for the AAA 173# server certificate in SubjectAltName dNSName element(s). If a 174# matching dNSName is found, this constraint is met. If no dNSName 175# values are present, this constraint is matched against SubjectName CN 176# using same suffix match comparison. Suffix match here means that the 177# host/domain name is compared one label at a time starting from the 178# top-level domain and all the labels in @domain_suffix_match shall be 179# included in the certificate. The certificate may include additional 180# sub-level labels in addition to the required labels. 181# 182# For example, domain_suffix_match=example.com would match 183# test.example.com but would not match test-example.com. 184# 185# domain: Home service provider FQDN(s) 186# This is used to compare against the Domain Name List to figure out 187# whether the AP is operated by the Home SP. Multiple domain entries can 188# be used to configure alternative FQDNs that will be considered home 189# networks. 190# 191# roaming_consortium: Roaming Consortium OI 192# If roaming_consortium_len is non-zero, this field contains the 193# Roaming Consortium OI that can be used to determine which access 194# points support authentication with this credential. This is an 195# alternative to the use of the realm parameter. When using Roaming 196# Consortium to match the network, the EAP parameters need to be 197# pre-configured with the credential since the NAI Realm information 198# may not be available or fetched. 199# 200# eap: Pre-configured EAP method 201# This optional field can be used to specify which EAP method will be 202# used with this credential. If not set, the EAP method is selected 203# automatically based on ANQP information (e.g., NAI Realm). 204# 205# phase1: Pre-configure Phase 1 (outer authentication) parameters 206# This optional field is used with like the 'eap' parameter. 207# 208# phase2: Pre-configure Phase 2 (inner authentication) parameters 209# This optional field is used with like the 'eap' parameter. 210# 211# excluded_ssid: Excluded SSID 212# This optional field can be used to excluded specific SSID(s) from 213# matching with the network. Multiple entries can be used to specify more 214# than one SSID. 215# 216# roaming_partner: Roaming partner information 217# This optional field can be used to configure preferences between roaming 218# partners. The field is a string in following format: 219# <FQDN>,<0/1 exact match>,<priority>,<* or country code> 220# (non-exact match means any subdomain matches the entry; priority is in 221# 0..255 range with 0 being the highest priority) 222# 223# update_identifier: PPS MO ID 224# (Hotspot 2.0 PerProviderSubscription/UpdateIdentifier) 225# 226# provisioning_sp: FQDN of the SP that provisioned the credential 227# This optional field can be used to keep track of the SP that provisioned 228# the credential to find the PPS MO (./Wi-Fi/<provisioning_sp>). 229# 230# sp_priority: Credential priority within a provisioning SP 231# This is the priority of the credential among all credentials 232# provisionined by the same SP (i.e., for entries that have identical 233# provisioning_sp value). The range of this priority is 0-255 with 0 234# being the highest and 255 the lower priority. 235# 236# Minimum backhaul threshold (PPS/<X+>/Policy/MinBackhauldThreshold/*) 237# These fields can be used to specify minimum download/upload backhaul 238# bandwidth that is preferred for the credential. This constraint is 239# ignored if the AP does not advertise WAN Metrics information or if the 240# limit would prevent any connection. Values are in kilobits per second. 241# min_dl_bandwidth_home 242# min_ul_bandwidth_home 243# min_dl_bandwidth_roaming 244# min_ul_bandwidth_roaming 245# 246# max_bss_load: Maximum BSS Load Channel Utilization (1..255) 247# (PPS/<X+>/Policy/MaximumBSSLoadValue) 248# This value is used as the maximum channel utilization for network 249# selection purposes for home networks. If the AP does not advertise 250# BSS Load or if the limit would prevent any connection, this constraint 251# will be ignored. 252# 253# req_conn_capab: Required connection capability 254# (PPS/<X+>/Policy/RequiredProtoPortTuple) 255# This value is used to configure set of required protocol/port pairs that 256# a roaming network shall support (include explicitly in Connection 257# Capability ANQP element). This constraint is ignored if the AP does not 258# advertise Connection Capability or if this constraint would prevent any 259# network connection. This policy is not used in home networks. 260# Format: <protocol>[:<comma-separated list of ports] 261# Multiple entries can be used to list multiple requirements. 262# For example, number of common TCP protocols: 263# req_conn_capab=6:22,80,443 264# For example, IPSec/IKE: 265# req_conn_capab=17:500 266# req_conn_capab=50 267# 268# ocsp: Whether to use/require OCSP to check server certificate 269# 0 = do not use OCSP stapling (TLS certificate status extension) 270# 1 = try to use OCSP stapling, but not require response 271# 2 = require valid OCSP stapling response 272# 273# sim_num: Identifier for which SIM to use in multi-SIM devices 274# 275# for example: 276# 277#cred={ 278# realm="example.com" 279# username="user@example.com" 280# password="password" 281# ca_cert="/etc/wpa_supplicant/ca.pem" 282# domain="example.com" 283# domain_suffix_match="example.com" 284#} 285# 286#cred={ 287# imsi="310026-000000000" 288# milenage="90dca4eda45b53cf0f12d7c9c3bc6a89:cb9cccc4b9258e6dca4760379fb82" 289#} 290# 291#cred={ 292# realm="example.com" 293# username="user" 294# password="password" 295# ca_cert="/etc/wpa_supplicant/ca.pem" 296# domain="example.com" 297# roaming_consortium=223344 298# eap=TTLS 299# phase2="auth=MSCHAPV2" 300#} 301 302 303Control interface 304----------------- 305 306wpa_supplicant provides a control interface that can be used from 307external programs to manage various operations. The included command 308line tool, wpa_cli, can be used for manual testing with this interface. 309 310Following wpa_cli interactive mode commands show some examples of manual 311operations related to Hotspot 2.0: 312 313Remove configured networks and credentials: 314 315> remove_network all 316OK 317> remove_cred all 318OK 319 320 321Add a username/password credential: 322 323> add_cred 3240 325> set_cred 0 realm "mail.example.com" 326OK 327> set_cred 0 username "username" 328OK 329> set_cred 0 password "password" 330OK 331> set_cred 0 priority 1 332OK 333> set_cred 0 temporary 1 334OK 335 336Add a SIM credential using a simulated SIM/USIM card for testing: 337 338> add_cred 3391 340> set_cred 1 imsi "23456-0000000000" 341OK 342> set_cred 1 milenage "90dca4eda45b53cf0f12d7c9c3bc6a89:cb9cccc4b9258e6dca4760379fb82581:000000000123" 343OK 344> set_cred 1 priority 1 345OK 346 347Note: the return value of add_cred is used as the first argument to 348the following set_cred commands. 349 350Add a SIM credential using a external SIM/USIM processing: 351 352> set external_sim 1 353OK 354> add_cred 3551 356> set_cred 1 imsi "23456-0000000000" 357OK 358> set_cred 1 eap SIM 359OK 360 361 362Add a WPA2-Enterprise network: 363 364> add_network 3650 366> set_network 0 key_mgmt WPA-EAP 367OK 368> set_network 0 ssid "enterprise" 369OK 370> set_network 0 eap TTLS 371OK 372> set_network 0 anonymous_identity "anonymous" 373OK 374> set_network 0 identity "user" 375OK 376> set_network 0 password "password" 377OK 378> set_network 0 priority 0 379OK 380> enable_network 0 no-connect 381OK 382 383 384Add an open network: 385 386> add_network 3873 388> set_network 3 key_mgmt NONE 389OK 390> set_network 3 ssid "coffee-shop" 391OK 392> select_network 3 393OK 394 395Note: the return value of add_network is used as the first argument to 396the following set_network commands. 397 398The preferred credentials/networks can be indicated with the priority 399parameter (1 is higher priority than 0). 400 401 402Interworking network selection can be started with interworking_select 403command. This instructs wpa_supplicant to run a network scan and iterate 404through the discovered APs to request ANQP information from the APs that 405advertise support for Interworking/Hotspot 2.0: 406 407> interworking_select 408OK 409<3>Starting ANQP fetch for 02:00:00:00:01:00 410<3>RX-ANQP 02:00:00:00:01:00 ANQP Capability list 411<3>RX-ANQP 02:00:00:00:01:00 Roaming Consortium list 412<3>RX-HS20-ANQP 02:00:00:00:01:00 HS Capability List 413<3>ANQP fetch completed 414<3>INTERWORKING-AP 02:00:00:00:01:00 type=unknown 415 416 417INTERWORKING-AP event messages indicate the APs that support network 418selection and for which there is a matching 419credential. interworking_connect command can be used to select a network 420to connect with: 421 422 423> interworking_connect 02:00:00:00:01:00 424OK 425<3>CTRL-EVENT-SCAN-RESULTS 426<3>SME: Trying to authenticate with 02:00:00:00:01:00 (SSID='Example Network' freq=2412 MHz) 427<3>Trying to associate with 02:00:00:00:01:00 (SSID='Example Network' freq=2412 MHz) 428<3>Associated with 02:00:00:00:01:00 429<3>CTRL-EVENT-EAP-STARTED EAP authentication started 430<3>CTRL-EVENT-EAP-PROPOSED-METHOD vendor=0 method=21 431<3>CTRL-EVENT-EAP-METHOD EAP vendor 0 method 21 (TTLS) selected 432<3>CTRL-EVENT-EAP-SUCCESS EAP authentication completed successfully 433<3>WPA: Key negotiation completed with 02:00:00:00:01:00 [PTK=CCMP GTK=CCMP] 434<3>CTRL-EVENT-CONNECTED - Connection to 02:00:00:00:01:00 completed (auth) [id=0 id_str=] 435 436 437wpa_supplicant creates a temporary network block for the selected 438network based on the configured credential and ANQP information from the 439AP: 440 441> list_networks 442network id / ssid / bssid / flags 4430 Example Network any [CURRENT] 444> get_network 0 key_mgmt 445WPA-EAP 446> get_network 0 eap 447TTLS 448 449 450Alternatively to using an external program to select the network, 451"interworking_select auto" command can be used to request wpa_supplicant 452to select which network to use based on configured priorities: 453 454 455> remove_network all 456OK 457<3>CTRL-EVENT-DISCONNECTED bssid=02:00:00:00:01:00 reason=1 locally_generated=1 458> interworking_select auto 459OK 460<3>Starting ANQP fetch for 02:00:00:00:01:00 461<3>RX-ANQP 02:00:00:00:01:00 ANQP Capability list 462<3>RX-ANQP 02:00:00:00:01:00 Roaming Consortium list 463<3>RX-HS20-ANQP 02:00:00:00:01:00 HS Capability List 464<3>ANQP fetch completed 465<3>INTERWORKING-AP 02:00:00:00:01:00 type=unknown 466<3>CTRL-EVENT-SCAN-RESULTS 467<3>SME: Trying to authenticate with 02:00:00:00:01:00 (SSID='Example Network' freq=2412 MHz) 468<3>Trying to associate with 02:00:00:00:01:00 (SSID='Example Network' freq=2412 MHz) 469<3>Associated with 02:00:00:00:01:00 470<3>CTRL-EVENT-EAP-STARTED EAP authentication started 471<3>CTRL-EVENT-EAP-PROPOSED-METHOD vendor=0 method=21 472<3>CTRL-EVENT-EAP-METHOD EAP vendor 0 method 21 (TTLS) selected 473<3>CTRL-EVENT-EAP-SUCCESS EAP authentication completed successfully 474<3>WPA: Key negotiation completed with 02:00:00:00:01:00 [PTK=CCMP GTK=CCMP] 475<3>CTRL-EVENT-CONNECTED - Connection to 02:00:00:00:01:00 completed (reauth) [id=0 id_str=] 476 477 478The connection status can be shown with the status command: 479 480> status 481bssid=02:00:00:00:01:00 482ssid=Example Network 483id=0 484mode=station 485pairwise_cipher=CCMP <--- link layer security indication 486group_cipher=CCMP 487key_mgmt=WPA2/IEEE 802.1X/EAP 488wpa_state=COMPLETED 489p2p_device_address=02:00:00:00:00:00 490address=02:00:00:00:00:00 491hs20=1 <--- HS 2.0 indication 492Supplicant PAE state=AUTHENTICATED 493suppPortStatus=Authorized 494EAP state=SUCCESS 495selectedMethod=21 (EAP-TTLS) 496EAP TLS cipher=AES-128-SHA 497EAP-TTLSv0 Phase2 method=PAP 498 499 500> status 501bssid=02:00:00:00:02:00 502ssid=coffee-shop 503id=3 504mode=station 505pairwise_cipher=NONE 506group_cipher=NONE 507key_mgmt=NONE 508wpa_state=COMPLETED 509p2p_device_address=02:00:00:00:00:00 510address=02:00:00:00:00:00 511 512 513Note: The Hotspot 2.0 indication is shown as "hs20=1" in the status 514command output. Link layer security is indicated with the 515pairwise_cipher (CCMP = secure, NONE = no encryption used). 516 517 518Also the scan results include the Hotspot 2.0 indication: 519 520> scan_results 521bssid / frequency / signal level / flags / ssid 52202:00:00:00:01:00 2412 -30 [WPA2-EAP-CCMP][ESS][HS20] Example Network 523 524 525ANQP information for the BSS can be fetched using the BSS command: 526 527> bss 02:00:00:00:01:00 528id=1 529bssid=02:00:00:00:01:00 530freq=2412 531beacon_int=100 532capabilities=0x0411 533qual=0 534noise=-92 535level=-30 536tsf=1345573286517276 537age=105 538ie=000f4578616d706c65204e6574776f726b010882848b960c1218240301012a010432043048606c30140100000fac040100000fac040100000fac0100007f04000000806b091e07010203040506076c027f006f1001531122331020304050010203040506dd05506f9a1000 539flags=[WPA2-EAP-CCMP][ESS][HS20] 540ssid=Example Network 541anqp_roaming_consortium=031122330510203040500601020304050603fedcba 542 543 544ANQP queries can also be requested with the anqp_get and hs20_anqp_get 545commands: 546 547> anqp_get 02:00:00:00:01:00 261 548OK 549<3>RX-ANQP 02:00:00:00:01:00 Roaming Consortium list 550> hs20_anqp_get 02:00:00:00:01:00 2 551OK 552<3>RX-HS20-ANQP 02:00:00:00:01:00 HS Capability List 553 554In addition, fetch_anqp command can be used to request similar set of 555ANQP queries to be done as is run as part of interworking_select: 556 557> scan 558OK 559<3>CTRL-EVENT-SCAN-RESULTS 560> fetch_anqp 561OK 562<3>Starting ANQP fetch for 02:00:00:00:01:00 563<3>RX-ANQP 02:00:00:00:01:00 ANQP Capability list 564<3>RX-ANQP 02:00:00:00:01:00 Roaming Consortium list 565<3>RX-HS20-ANQP 02:00:00:00:01:00 HS Capability List 566<3>ANQP fetch completed 567