561 lines
20 KiB
Plaintext
561 lines
20 KiB
Plaintext
wpa_supplicant and Wi-Fi P2P
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============================
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This document describes how the Wi-Fi P2P implementation in
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wpa_supplicant can be configured and how an external component on the
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client (e.g., management GUI) is used to enable WPS enrollment and
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registrar registration.
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Introduction to Wi-Fi P2P
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-------------------------
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TODO
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More information about Wi-Fi P2P is available from Wi-Fi Alliance:
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http://www.wi-fi.org/Wi-Fi_Direct.php
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wpa_supplicant implementation
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-----------------------------
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TODO
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wpa_supplicant configuration
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----------------------------
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Wi-Fi P2P is an optional component that needs to be enabled in the
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wpa_supplicant build configuration (.config). Here is an example
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configuration that includes Wi-Fi P2P support and Linux nl80211
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-based driver interface:
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CONFIG_DRIVER_NL80211=y
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CONFIG_CTRL_IFACE=y
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CONFIG_P2P=y
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CONFIG_AP=y
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CONFIG_WPS=y
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In run-time configuration file (wpa_supplicant.conf), some parameters
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for P2P may be set. In order to make the devices easier to recognize,
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device_name and device_type should be specified. For example,
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something like this should be included:
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ctrl_interface=/var/run/wpa_supplicant
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device_name=My P2P Device
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device_type=1-0050F204-1
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wpa_cli
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-------
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Actual Wi-Fi P2P operations are requested during runtime. These can be
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done for example using wpa_cli (which is described below) or a GUI
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like wpa_gui-qt4.
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wpa_cli starts in interactive mode if no command string is included on
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the command line. By default, it will select the first network interface
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that it can find (and that wpa_supplicant controls). If more than one
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interface is in use, it may be necessary to select one of the explicitly
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by adding -i argument on the command line (e.g., 'wpa_cli -i wlan1').
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Most of the P2P operations are done on the main interface (e.g., the
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interface that is automatically added when the driver is loaded, e.g.,
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wlan0). When using a separate virtual interface for group operations
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(e.g., wlan1), the control interface for that group interface may need
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to be used for some operations (mainly WPS activation in GO). This may
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change in the future so that all the needed operations could be done
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over the main control interface.
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Device Discovery
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p2p_find [timeout in seconds] [type=<social|progressive>] \
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[dev_id=<addr>] [delay=<search delay in ms>]
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The default behavior is to run a single full scan in the beginning and
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then scan only social channels. type=social will scan only social
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channels, i.e., it skips the initial full scan. type=progressive is
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like the default behavior, but it will scan through all the channels
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progressively one channel at the time in the Search state rounds. This
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will help in finding new groups or groups missed during the initial
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full scan.
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The optional dev_id option can be used to specify a single P2P peer to
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search for. The optional delay parameter can be used to request an extra
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delay to be used between search iterations (e.g., to free up radio
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resources for concurrent operations).
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p2p_listen [timeout in seconds]
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Start Listen-only state (become discoverable without searching for
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other devices). Optional parameter can be used to specify the duration
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for the Listen operation in seconds. This command may not be of that
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much use during normal operations and is mainly designed for
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testing. It can also be used to keep the device discoverable without
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having to maintain a group.
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p2p_stop_find
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Stop ongoing P2P device discovery or other operation (connect, listen
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mode).
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p2p_flush
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Flush P2P peer table and state.
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Group Formation
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p2p_prov_disc <peer device address> <display|keypad|pbc> [join|auto]
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Send P2P provision discovery request to the specified peer. The
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parameters for this command are the P2P device address of the peer and
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the desired configuration method. For example, "p2p_prov_disc
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02:01:02:03:04:05 display" would request the peer to display a PIN for
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us and "p2p_prov_disc 02:01:02:03:04:05 keypad" would request the peer
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to enter a PIN that we display.
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The optional "join" parameter can be used to indicate that this command
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is requesting an already running GO to prepare for a new client. This is
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mainly used with "display" to request it to display a PIN. The "auto"
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parameter can be used to request wpa_supplicant to automatically figure
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out whether the peer device is operating as a GO and if so, use
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join-a-group style PD instead of GO Negotiation style PD.
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p2p_connect <peer device address> <pbc|pin|PIN#> [display|keypad]
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[persistent|persistent=<network id>] [join|auth]
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[go_intent=<0..15>] [freq=<in MHz>] [ht40] [provdisc]
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Start P2P group formation with a discovered P2P peer. This includes
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optional group owner negotiation, group interface setup, provisioning,
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and establishing data connection.
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The <pbc|pin|PIN#> parameter specifies the WPS provisioning
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method. "pbc" string starts pushbutton method, "pin" string start PIN
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method using an automatically generated PIN (which will be returned as
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the command return code), PIN# means that a pre-selected PIN can be
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used (e.g., 12345670). [display|keypad] is used with PIN method
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to specify which PIN is used (display=dynamically generated random PIN
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from local display, keypad=PIN entered from peer display). "persistent"
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parameter can be used to request a persistent group to be formed. The
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"persistent=<network id>" alternative can be used to pre-populate
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SSID/passphrase configuration based on a previously used persistent
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group where this device was the GO. The previously used parameters will
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then be used if the local end becomes the GO in GO Negotiation (which
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can be forced with go_intent=15).
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"join" indicates that this is a command to join an existing group as a
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client. It skips the GO Negotiation part. This will send a Provision
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Discovery Request message to the target GO before associating for WPS
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provisioning.
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"auth" indicates that the WPS parameters are authorized for the peer
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device without actually starting GO Negotiation (i.e., the peer is
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expected to initiate GO Negotiation). This is mainly for testing
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purposes.
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"go_intent" can be used to override the default GO Intent for this GO
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Negotiation.
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"freq" can be used to set a forced operating channel (e.g., freq=2412
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to select 2.4 GHz channel 1).
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"provdisc" can be used to request a Provision Discovery exchange to be
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used prior to starting GO Negotiation as a workaround with some deployed
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P2P implementations that require this to allow the user to accept the
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connection.
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p2p_group_add [persistent|persistent=<network id>] [freq=<freq in MHz>] [ht40]
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Set up a P2P group owner manually (i.e., without group owner
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negotiation with a specific peer). This is also known as autonomous
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GO. Optional persistent=<network id> can be used to specify restart of
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a persistent group. Optional freq=<freq in MHz> can be used to force
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the GO to be started on a specific frequency. Special freq=2 or freq=5
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options can be used to request the best 2.4 GHz or 5 GHz band channel
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to be selected automatically.
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p2p_reject <peer device address>
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Reject connection attempt from a peer (specified with a device
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address). This is a mechanism to reject a pending GO Negotiation with
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a peer and request to automatically block any further connection or
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discovery of the peer.
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p2p_group_remove <group interface>
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Terminate a P2P group. If a new virtual network interface was used for
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the group, it will also be removed. The network interface name of the
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group interface is used as a parameter for this command.
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p2p_cancel
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Cancel an ongoing P2P group formation and joining-a-group related
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operation. This operations unauthorizes the specific peer device (if any
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had been authorized to start group formation), stops P2P find (if in
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progress), stops pending operations for join-a-group, and removes the
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P2P group interface (if one was used) that is in the WPS provisioning
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step. If the WPS provisioning step has been completed, the group is not
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terminated.
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Service Discovery
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p2p_serv_disc_req
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Schedule a P2P service discovery request. The parameters for this
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command are the device address of the peer device (or 00:00:00:00:00:00
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for wildcard query that is sent to every discovered P2P peer that
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supports service discovery) and P2P Service Query TLV(s) as hexdump. For
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example,
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p2p_serv_disc_req 00:00:00:00:00:00 02000001
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schedules a request for listing all available services of all service
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discovery protocols and requests this to be sent to all discovered
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peers (note: this can result in long response frames). The pending
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requests are sent during device discovery (see p2p_find).
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Only a single pending wildcard query is supported, but there can be
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multiple pending peer device specific queries (each will be sent in
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sequence whenever the peer is found).
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This command returns an identifier for the pending query (e.g.,
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"1f77628") that can be used to cancel the request. Directed requests
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will be automatically removed when the specified peer has replied to
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it.
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For UPnP, an alternative command format can be used to specify a
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single query TLV (i.e., a service discovery for a specific UPnP
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service):
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p2p_serv_disc_req 00:00:00:00:00:00 upnp <version hex> <ST: from M-SEARCH>
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For example:
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p2p_serv_disc_req 00:00:00:00:00:00 upnp 10 urn:schemas-upnp-org:device:InternetGatewayDevice:1
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Additional examples for queries:
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# list of all Bonjour services
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p2p_serv_disc_req 00:00:00:00:00:00 02000101
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# list of all UPnP services
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p2p_serv_disc_req 00:00:00:00:00:00 02000201
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# list of all WS-Discovery services
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p2p_serv_disc_req 00:00:00:00:00:00 02000301
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# list of all Bonjour and UPnP services
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p2p_serv_disc_req 00:00:00:00:00:00 0200010102000202
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# Apple File Sharing over TCP
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p2p_serv_disc_req 00:00:00:00:00:00 130001010b5f6166706f766572746370c00c000c01
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# Bonjour SSTH (supported service type hash)
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p2p_serv_disc_req 00:00:00:00:00:00 05000101000000
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# UPnP examples
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p2p_serv_disc_req 00:00:00:00:00:00 upnp 10 ssdp:all
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p2p_serv_disc_req 00:00:00:00:00:00 upnp 10 upnp:rootdevice
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p2p_serv_disc_req 00:00:00:00:00:00 upnp 10 urn:schemas-upnp-org:service:ContentDirectory:2
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p2p_serv_disc_req 00:00:00:00:00:00 upnp 10 uuid:6859dede-8574-59ab-9332-123456789012
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p2p_serv_disc_req 00:00:00:00:00:00 upnp 10 urn:schemas-upnp-org:device:InternetGatewayDevice:1
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# Wi-Fi Display examples
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# format: wifi-display <list of roles> <list of subelements>
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p2p_serv_disc_req 00:00:00:00:00:00 wifi-display [source] 2,3,4,5
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p2p_serv_disc_req 02:01:02:03:04:05 wifi-display [pri-sink] 3
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p2p_serv_disc_req 00:00:00:00:00:00 wifi-display [sec-source] 2
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p2p_serv_disc_req 00:00:00:00:00:00 wifi-display [source+sink] 2,3,4,5
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p2p_serv_disc_req 00:00:00:00:00:00 wifi-display [source][pri-sink] 2,3,4,5
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p2p_serv_disc_cancel_req <query identifier>
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Cancel a pending P2P service discovery request. This command takes a
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single parameter: identifier for the pending query (the value returned
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by p2p_serv_disc_req, e.g., "p2p_serv_disc_cancel_req 1f77628".
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p2p_serv_disc_resp
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Reply to a service discovery query. This command takes following
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parameters: frequency in MHz, destination address, dialog token,
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response TLV(s). The first three parameters are copied from the
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request event. For example, "p2p_serv_disc_resp 2437 02:40:61:c2:f3:b7
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1 0300000101". This command is used only if external program is used
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to process the request (see p2p_serv_disc_external).
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p2p_service_update
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Indicate that local services have changed. This is used to increment
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the P2P service indicator value so that peers know when previously
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cached information may have changed. This is only needed when external
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service discovery processing is enabled since the commands to
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pre-configure services for internal processing will increment the
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indicator automatically.
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p2p_serv_disc_external <0|1>
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Configure external processing of P2P service requests: 0 (default) =
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no external processing of requests (i.e., internal code will process
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each request based on pre-configured services), 1 = external
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processing of requests (external program is responsible for replying
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to service discovery requests with p2p_serv_disc_resp). Please note
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that there is quite strict limit on how quickly the response needs to
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be transmitted, so use of the internal processing is strongly
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recommended.
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p2p_service_add bonjour <query hexdump> <RDATA hexdump>
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Add a local Bonjour service for internal SD query processing.
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Examples:
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# AFP Over TCP (PTR)
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p2p_service_add bonjour 0b5f6166706f766572746370c00c000c01 074578616d706c65c027
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# AFP Over TCP (TXT) (RDATA=null)
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p2p_service_add bonjour 076578616d706c650b5f6166706f766572746370c00c001001 00
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# IP Printing over TCP (PTR) (RDATA=MyPrinter._ipp._tcp.local.)
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p2p_service_add bonjour 045f697070c00c000c01 094d795072696e746572c027
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# IP Printing over TCP (TXT) (RDATA=txtvers=1,pdl=application/postscript)
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p2p_service_add bonjour 096d797072696e746572045f697070c00c001001 09747874766572733d311a70646c3d6170706c69636174696f6e2f706f7374736372797074
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# Supported Service Type Hash (SSTH)
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p2p_service_add bonjour 000000 <32-byte bitfield as hexdump>
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(note: see P2P spec Annex E.4 for information on how to construct the bitfield)
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p2p_service_del bonjour <query hexdump>
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Remove a local Bonjour service from internal SD query processing.
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p2p_service_add upnp <version hex> <service>
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Add a local UPnP service for internal SD query processing.
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Examples:
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p2p_service_add upnp 10 uuid:6859dede-8574-59ab-9332-123456789012::upnp:rootdevice
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p2p_service_add upnp 10 uuid:5566d33e-9774-09ab-4822-333456785632::upnp:rootdevice
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p2p_service_add upnp 10 uuid:1122de4e-8574-59ab-9322-333456789044::urn:schemas-upnp-org:service:ContentDirectory:2
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p2p_service_add upnp 10 uuid:5566d33e-9774-09ab-4822-333456785632::urn:schemas-upnp-org:service:ContentDirectory:2
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p2p_service_add upnp 10 uuid:6859dede-8574-59ab-9332-123456789012::urn:schemas-upnp-org:device:InternetGatewayDevice:1
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p2p_service_del upnp <version hex> <service>
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Remove a local UPnP service from internal SD query processing.
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p2p_service_flush
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Remove all local services from internal SD query processing.
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Invitation
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p2p_invite [persistent=<network id>|group=<group ifname>] [peer=address]
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[go_dev_addr=address] [freq=<freq in MHz>] [ht40]
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Invite a peer to join a group (e.g., group=wlan1) or to reinvoke a
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persistent group (e.g., persistent=4). If the peer device is the GO of
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the persistent group, the peer parameter is not needed. Otherwise it is
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used to specify which device to invite. go_dev_addr parameter can be
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used to override the GO device address for Invitation Request should
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it be not known for some reason (this should not be needed in most
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cases). When reinvoking a persistent group, the GO device can specify
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the frequency for the group with the freq parameter.
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Group Operations
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(These are used on the group interface.)
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wps_pin <any|address> <PIN>
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Start WPS PIN method. This allows a single WPS Enrollee to connect to
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the AP/GO. This is used on the GO when a P2P client joins an existing
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group. The second parameter is the address of the Enrollee or a string
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"any" to allow any station to use the entered PIN (which will restrict
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the PIN for one-time-use). PIN is the Enrollee PIN read either from a
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label or display on the P2P Client/WPS Enrollee.
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wps_pbc
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Start WPS PBC method (i.e., push the button). This allows a single WPS
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Enrollee to connect to the AP/GO. This is used on the GO when a P2P
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client joins an existing group.
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p2p_get_passphrase
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Get the passphrase for a group (only available when acting as a GO).
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p2p_presence_req [<duration> <interval>] [<duration> <interval>]
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Send a P2P Presence Request to the GO (this is only available when
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acting as a P2P client). If no duration/interval pairs are given, the
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request indicates that this client has no special needs for GO
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presence. the first parameter pair gives the preferred duration and
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interval values in microseconds. If the second pair is included, that
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indicates which value would be acceptable.
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Parameters
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p2p_ext_listen [<period> <interval>]
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Configure Extended Listen Timing. If the parameters are omitted, this
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feature is disabled. If the parameters are included, Listen State will
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be entered every interval msec for at least period msec. Both values
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have acceptable range of 1-65535 (with interval obviously having to be
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larger than or equal to duration). If the P2P module is not idle at
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the time the Extended Listen Timing timeout occurs, the Listen State
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operation will be skipped.
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The configured values will also be advertised to other P2P Devices. The
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received values are available in the p2p_peer command output:
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ext_listen_period=100 ext_listen_interval=5000
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p2p_set <field> <value>
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Change dynamic P2P parameters
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p2p_set discoverability <0/1>
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Disable/enable advertisement of client discoverability. This is
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enabled by default and this parameter is mainly used to allow testing
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of device discoverability.
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p2p_set managed <0/1>
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Disable/enable managed P2P Device operations. This is disabled by
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default.
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p2p_set listen_channel <1/6/11>
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Set P2P Listen channel. This is mainly meant for testing purposes and
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changing the Listen channel during normal operations can result in
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protocol failures.
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p2p_set ssid_postfix <postfix>
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Set postfix string to be added to the automatically generated P2P SSID
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(DIRECT-<two random characters>). For example, postfix of "-testing"
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could result in the SSID becoming DIRECT-ab-testing.
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set <field> <value>
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Set global configuration parameters which may also affect P2P
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operations. The format on these parameters is same as is used in
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wpa_supplicant.conf. Only the parameters listen here should be
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changed. Modifying other parameters may result in incorrect behavior
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since not all existing users of the parameters are updated.
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set uuid <UUID>
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Set WPS UUID (by default, this is generated based on the MAC address).
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set device_name <device name>
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Set WPS Device Name (also included in some P2P messages).
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set manufacturer <manufacturer>
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Set WPS Manufacturer.
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set model_name <model name>
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Set WPS Model Name.
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set model_number <model number>
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Set WPS Model Number.
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set serial_number <serial number>
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Set WPS Serial Number.
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set device_type <device type>
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Set WPS Device Type.
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set os_version <OS version>
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Set WPS OS Version.
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set config_methods <config methods>
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Set WPS Configuration Methods.
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set sec_device_type <device type>
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Add a new Secondary Device Type.
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set p2p_go_intent <GO intent>
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|
|
Set the default P2P GO Intent. Note: This value can be overridden in
|
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p2p_connect command and as such, there should be no need to change the
|
|
default value here during normal operations.
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set p2p_ssid_postfix <P2P SSID postfix>
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|
|
Set P2P SSID postfix.
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|
|
|
set persistent_reconnect <0/1>
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|
|
|
Disable/enabled persistent reconnect for reinvocation of persistent
|
|
groups. If enabled, invitations to reinvoke a persistent group will be
|
|
accepted without separate authorization (e.g., user interaction).
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|
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|
set country <two character country code>
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|
|
|
Set country code (this is included in some P2P messages).
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|
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|
Status
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|
|
p2p_peers [discovered]
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|
|
|
List P2P Device Addresses of all the P2P peers we know. The optional
|
|
"discovered" parameter filters out the peers that we have not fully
|
|
discovered, i.e., which we have only seen in a received Probe Request
|
|
frame.
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|
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|
p2p_peer <P2P Device Address>
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|
|
|
Fetch information about a known P2P peer.
|
|
|
|
Group Status
|
|
|
|
(These are used on the group interface.)
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|
|
|
status
|
|
|
|
Show status information (connection state, role, use encryption
|
|
parameters, IP address, etc.).
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|
|
|
sta
|
|
|
|
Show information about an associated station (when acting in AP/GO role).
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|
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|
all_sta
|
|
|
|
Lists the currently associated stations.
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|
|
|
Configuration data
|
|
|
|
list_networks
|
|
|
|
Lists the configured networks, including stored information for
|
|
persistent groups. The identifier in this list is used with
|
|
p2p_group_add and p2p_invite to indicate which persistent group is to
|
|
be reinvoked.
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|
|
|
remove_network <network id>
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|
|
|
Remove a network entry from configuration.
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|
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|
|
wpa_cli action script
|
|
---------------------
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|
|
|
See examples/p2p-action.sh
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|
|
|
TODO: describe DHCP/DNS setup
|
|
TODO: cross-connection
|