wpa_supplicant implements a control interface that can be used by external programs to control the operations of the wpa_supplicant daemon and to get status information and event notifications. There is a small C library, in a form of a single C file, wpa_ctrl.c, that provides helper functions to facilitate the use of the control interface. External programs can link this file into them and then use the library functions documented in wpa_ctrl.h to interact with wpa_supplicant. This library can also be used with C++. wpa_cli.c and wpa_gui are example programs using this library.
There are multiple mechanisms for inter-process communication. For example, Linux version of wpa_supplicant is using UNIX domain sockets for the control interface and Windows version UDP sockets. The use of the functions defined in wpa_ctrl.h can be used to hide the details of the used IPC from external programs.
External programs, e.g., a GUI or a configuration utility, that need to communicate with wpa_supplicant should link in wpa_ctrl.c. This allows them to use helper functions to open connection to the control interface with wpa_ctrl_open() and to send commands with wpa_ctrl_request().
wpa_supplicant uses the control interface for two types of communication: commands and unsolicited event messages. Commands are a pair of messages, a request from the external program and a response from wpa_supplicant. These can be executed using wpa_ctrl_request(). Unsolicited event messages are sent by wpa_supplicant to the control interface connection without specific request from the external program for receiving each message. However, the external program needs to attach to the control interface with wpa_ctrl_attach() to receive these unsolicited messages.
If the control interface connection is used both for commands and unsolicited event messages, there is potential for receiving an unsolicited message between the command request and response. wpa_ctrl_request() caller will need to supply a callback, msg_cb, for processing these messages. Often it is easier to open two control interface connections by calling wpa_ctrl_open() twice and then use one of the connections for commands and the other one for unsolicited messages. This way command request/response pairs will not be broken by unsolicited messages. wpa_cli is an example of how to use only one connection for both purposes and wpa_gui demonstrates how to use two separate connections.
Once the control interface connection is not needed anymore, it should be closed by calling wpa_ctrl_close(). If the connection was used for unsolicited event messages, it should be first detached by calling wpa_ctrl_detach().
Following commands can be used with wpa_ctrl_request():
This command can be used to test whether wpa_supplicant is replying to the control interface commands. The expected reply is PONG if the connection is open and wpa_supplicant is processing commands.
Request a list of MIB variables (dot1x, dot11). The output is a text block with each line in variable=value format. For example:
dot11RSNAOptionImplemented=TRUE dot11RSNAPreauthenticationImplemented=TRUE dot11RSNAEnabled=FALSE dot11RSNAPreauthenticationEnabled=FALSE dot11RSNAConfigVersion=1 dot11RSNAConfigPairwiseKeysSupported=5 dot11RSNAConfigGroupCipherSize=128 dot11RSNAConfigPMKLifetime=43200 dot11RSNAConfigPMKReauthThreshold=70 dot11RSNAConfigNumberOfPTKSAReplayCounters=1 dot11RSNAConfigSATimeout=60 dot11RSNAAuthenticationSuiteSelected=00-50-f2-2 dot11RSNAPairwiseCipherSelected=00-50-f2-4 dot11RSNAGroupCipherSelected=00-50-f2-4 dot11RSNAPMKIDUsed= dot11RSNAAuthenticationSuiteRequested=00-50-f2-2 dot11RSNAPairwiseCipherRequested=00-50-f2-4 dot11RSNAGroupCipherRequested=00-50-f2-4 dot11RSNAConfigNumberOfGTKSAReplayCounters=0 dot11RSNA4WayHandshakeFailures=0 dot1xSuppPaeState=5 dot1xSuppHeldPeriod=60 dot1xSuppAuthPeriod=30 dot1xSuppStartPeriod=30 dot1xSuppMaxStart=3 dot1xSuppSuppControlledPortStatus=Authorized dot1xSuppBackendPaeState=2 dot1xSuppEapolFramesRx=0 dot1xSuppEapolFramesTx=440 dot1xSuppEapolStartFramesTx=2 dot1xSuppEapolLogoffFramesTx=0 dot1xSuppEapolRespFramesTx=0 dot1xSuppEapolReqIdFramesRx=0 dot1xSuppEapolReqFramesRx=0 dot1xSuppInvalidEapolFramesRx=0 dot1xSuppEapLengthErrorFramesRx=0 dot1xSuppLastEapolFrameVersion=0 dot1xSuppLastEapolFrameSource=00:00:00:00:00:00
Request current WPA/EAPOL/EAP status information. The output is a text block with each line in variable=value format. For example:
bssid=02:00:01:02:03:04 ssid=test network pairwise_cipher=CCMP group_cipher=CCMP key_mgmt=WPA-PSK wpa_state=COMPLETED ip_address=192.168.1.21 Supplicant PAE state=AUTHENTICATED suppPortStatus=Authorized EAP state=SUCCESS
Same as STATUS, but with more verbosity (i.e., more variable=value pairs).
bssid=02:00:01:02:03:04 ssid=test network id=0 pairwise_cipher=CCMP group_cipher=CCMP key_mgmt=WPA-PSK wpa_state=COMPLETED ip_address=192.168.1.21 Supplicant PAE state=AUTHENTICATED suppPortStatus=Authorized heldPeriod=60 authPeriod=30 startPeriod=30 maxStart=3 portControl=Auto Supplicant Backend state=IDLE EAP state=SUCCESS reqMethod=0 methodState=NONE decision=COND_SUCC ClientTimeout=60
Show PMKSA cache
Index / AA / PMKID / expiration (in seconds) / opportunistic 1 / 02:00:01:02:03:04 / 000102030405060708090a0b0c0d0e0f / 41362 / 0 2 / 02:00:01:33:55:77 / 928389281928383b34afb34ba4212345 / 362 / 1
Set variables:
Example command:
SET EAPOL::heldPeriod 45
IEEE 802.1X EAPOL state machine logon.
IEEE 802.1X EAPOL state machine logoff.
Force reassociation.
Connect if disconnected (i.e., like REASSOCIATE, but only connect if in disconnected state).
Start pre-authentication with the given BSSID.
Attach the connection as a monitor for unsolicited events. This can be done with wpa_ctrl_attach().
Detach the connection as a monitor for unsolicited events. This can be done with wpa_ctrl_detach().
Change debug level.
Force wpa_supplicant to re-read its configuration data.
Terminate wpa_supplicant process.
Set preferred BSSID for a network. Network id can be received from the LIST_NETWORKS command output.
List configured networks.
network id / ssid / bssid / flags 0 example network any [CURRENT]
(note: fields are separated with tabs)
Disconnect and wait for REASSOCIATE or RECONNECT command before connecting.
Request a new BSS scan.
Get the latest scan results.
bssid / frequency / signal level / flags / ssid 00:09:5b:95:e0:4e 2412 208 [WPA-PSK-CCMP] jkm private 02:55:24:33:77:a3 2462 187 [WPA-PSK-TKIP] testing 00:09:5b:95:e0:4f 2412 209 jkm guest
(note: fields are separated with tabs)
Get detailed per-BSS scan results. BSS command can be used to iterate through scan results one BSS at a time and to fetch all information from the found BSSes. This provides access to the same data that is available through SCAN_RESULTS but in a way that avoids problems with large number of scan results not fitting in the ctrl_iface messages.
There are two options for selecting the BSS with the BSS command: "BSS <idx>" requests information for the BSS identified by the index (0 .. size-1) in the scan results table and "BSS <BSSID>" requests information for the given BSS (based on BSSID in 00:01:02:03:04:05 format).
BSS information is presented in following format. Please note that new fields may be added to this field=value data, so the ctrl_iface user should be prepared to ignore values it does not understand.
bssid=00:09:5b:95:e0:4e freq=2412 beacon_int=0 capabilities=0x0011 qual=51 noise=161 level=212 tsf=0000000000000000 ie=000b6a6b6d2070726976617465010180dd180050f20101000050f20401000050f20401000050f2020000 ssid=jkm private
Select a network (disable others). Network id can be received from the LIST_NETWORKS command output.
Enable a network. Network id can be received from the LIST_NETWORKS command output. Special network id all can be used to enable all network.
Disable a network. Network id can be received from the LIST_NETWORKS command output. Special network id all can be used to disable all network.
Add a new network. This command creates a new network with empty configuration. The new network is disabled and once it has been configured it can be enabled with ENABLE_NETWORK command. ADD_NETWORK returns the network id of the new network or FAIL on failure.
Remove a network. Network id can be received from the LIST_NETWORKS command output. Special network id all can be used to remove all network.
Set network variables. Network id can be received from the LIST_NETWORKS command output.
This command uses the same variables and data formats as the configuration file. See example wpa_supplicant.conf for more details.
Get network variables. Network id can be received from the LIST_NETWORKS command output.
Save the current configuration.
If wpa_supplicant needs additional information during authentication (e.g., password), it will use a specific prefix, CTRL-REQ- (WPA_CTRL_REQ macro) in an unsolicited event message. An external program, e.g., a GUI, can provide such information by using CTRL-RSP- (WPA_CTRL_RSP macro) prefix in a command with matching field name.
The following fields can be requested in this way from the user:
CTRL-REQ-<field name>-<network id>-<human readable text> CTRL-RSP-<field name>-<network id>-<value>
For example, request from wpa_supplicant:
CTRL-REQ-PASSWORD-1-Password needed for SSID test-network
And a matching reply from the GUI:
CTRL-RSP-PASSWORD-1-secret
Get list of supported functionality (eap, pairwise, group, proto). Supported functionality is shown as space separate lists of values used in the same format as in wpa_supplicant configuration. If optional argument, 'strict', is added, only the values that the driver claims to explicitly support are included. Without this, all available capabilities are included if the driver does not provide a mechanism for querying capabilities.
Example request/reply pairs:
GET_CAPABILITY eap AKA FAST GTC LEAP MD5 MSCHAPV2 OTP PAX PEAP PSK SIM TLS TTLS
GET_CAPABILITY pairwise CCMP TKIP NONE
GET_CAPABILITY pairwise strict
GET_CAPABILITY group CCMP TKIP WEP104 WEP40
GET_CAPABILITY key_mgmt WPA-PSK WPA-EAP IEEE8021X NONE
GET_CAPABILITY proto RSN WPA
GET_CAPABILITY auth_alg OPEN SHARED LEAP
Change ap_scan value: 0 = no scanning, 1 = wpa_supplicant requests scans and uses scan results to select the AP, 2 = wpa_supplicant does not use scanning and just requests driver to associate and take care of AP selection
List configured interfaces.
wlan0 eth0
1.6.1
