xref: /aosp_15_r20/external/wpa_supplicant_8/wpa_supplicant/README-NAN-USD (revision 03f9172ca588f91df233974f4258bab95191f931)

Wi-Fi Aware unsynchronized service discovery (NAN USD)
======================================================

This document descibes how the unsynchronized service discovery defined
in the Wi-Fi Aware specification v4.0 can be used with wpa_spplicant.

More information about Wi-Fi Aware is available from this Wi-Fi
Alliance web page:
https://www.wi-fi.org/discover-wi-fi/wi-fi-aware

Build config setup
------------------

The following parameters must be included in the config file used to
compile hostapd and wpa_supplicant.

wpa_supplicant build config
---------------------------

Enable NAN USD in wpa_supplicant build config file

CONFIG_NAN_USD=y

Control interface commands and events
-------------------------------------

Following control interface commands can be used:

NAN_PUBLISH service_name=<name> [ttl=<time-to-live-in-sec>] [freq=<in MHz>] [freq_list=<comma separate list of MHz>] [srv_proto_type=<type>] [ssi=<service specific information (hexdump)>] [solicited=0] [unsolicited=0] [fsd=0]

If ttl=0 or the parameter is not included, only one Publish message is
transmitted.

If freq is not included, the default frequency 2437 MHz (channel 6 on
the 2.4 GHz band) is used.

If freq_list is included, publisher iterates over all the listed
channels. A special freq_list=all value can be used to generate the
channel list automatically based on the list of allowed 2.4 and 5 GHz
channels.

srv_proto_type values are defined in the Service Protocol Types table in
the Wi-Fi Aware specification.

This command returns the assigned publish_id value or FAIL on failure.

This command maps to the Publish() method in the NAN Discovery Engine.

NAN_CANCEL_PUBLISH publish_id=<id from NAN_PUBLISH>

This command maps to the CancelPublish() method in the NAN Discovery
Engine.

NAN_UPDATE_PUBLISH publish_id=<id from NAN_PUBLISH> [ssi=<service specific information (hexdump)>]

This command maps to the UpdatePublish() method in the NAN Discovery
Engine.

NAN_SUBSCRIBE service_name=<name> [active=1] [ttl=<time-to-live-in-sec>] [freq=<in MHz>] [srv_proto_type=<type>] [ssi=<service specific information (hexdump)>]

If ttl=0 or the parameter is not included, operation is terminated once
the first matching publisher is found.

If freq is not included, the default frequency 2437 MHz (channel 6 on
the 2.4 GHz band) is used.

srv_proto_type values are defined in the Service Protocol Types table in
the Wi-Fi Aware specification.

This command returns the assigned subscribe_id value or FAIL on failure.

This command maps to the Subscribe() method in the NAN Discovery Engine.

NAN_CANCEL_SUBSCRIBE subscribe_id=<id from NAN_SUBSCRIBE>

This command maps to the CancelSubscribe() method in the NAN Discovery Engine.

NAN_TRANSMIT handle=<id from NAN_PUBLISH or NAN_SUBSCRIBE> req_instance_id=<peer's id> address=<peer's MAC address> [ssi=<service specific information (hexdump)>]

This command maps to the Transmit() method in the NAN Discovery Engine.

Following control interface events are used:

NAN-DISCOVERY-RESULT subscribe_id=<own id> publish_id=<peer's id> address=<peer MAC address> fsd=<0/1> fsd_gas=<0/1> srv_proto_type=<type> ssi=<service specific information (hexdump)>

This event maps to the DiscoveryResult() event in the NAN Discovery
Engine.

NAN-REPLIED publish_id=<own id> address=<peer MAC address> subscribe_id=<peer id> srv_proto_type=<ype> ssi=<service specific information (hexdump)>

This event maps to the Replied() event in the NAN Discovery Engine.

NAN-PUBLISH-TERMINATED publish_id=<own id> reason=<timeout/user-request/failure>

This event maps to the PublishTerminated() event in the NAN Discovery
Engine.

NAN-SUBSCRIBE-TERMINATED subscribe_id=<own id> reason=<timeout/user-request/failure>

This event maps to the SubscribeTerminate() event in the NAN Discovery
Engine.

NAN-RECEIVE id=<own id> peer_instance_id=<peer id> address=<peer MAC adress> ssi=<service specific information (hexdump)>

This event maps to the Receive() event in the NAN Discovery Engine.


Example operation
-----------------

Start Subscribe and Publish functions:

dev0: NAN_SUBSCRIBE service_name=_test srv_proto_type=3 ssi=1122334455
--> returns 7

dev1: NAN_PUBLISH service_name=_test srv_proto_type=3 ssi=6677
--> returns 5

Subscriber notification of a discovery:

event on dev0: <3>NAN-DISCOVERY-RESULT subscribe_id=7 publish_id=5 address=02:00:00:00:01:00 fsd=1 fsd_gas=0 srv_proto_type=3 ssi=6677

Publisher notification of a Follow-up message with no ssi (to enter
paused state to continue exchange with the subscriber):

event on dev1: <3>NAN-RECEIVE id=5 peer_instance_id=7 address=02:00:00:00:00:00 ssi=

Subscriber sending a Follow-up message:

dev0: NAN_TRANSMIT handle=7 req_instance_id=5 address=02:00:00:00:01:00 ssi=8899

Publisher receiving the Follow-up message:

event on dev1: <3>NAN-RECEIVE id=5 peer_instance_id=7 address=02:00:00:00:00:00 ssi=8899

Publisher sending a Follow-up message:

dev1: NAN_TRANSMIT handle=5 req_instance_id=7 address=02:00:00:00:00:00 ssi=aabbccdd

Subscriber receiving the Follow-up message:

event on dev0: <3>NAN-RECEIVE id=7 peer_instance_id=5 address=02:00:00:00:01:00 ssi=aabbccdd

Stop Subscribe and Publish functions:

dev0: NAN_CANCEL_SUBSCRIBE subscribe_id=7
dev1: NAN_CANCEL_PUBLIST publish_id=5