Android Nearby Share compatibility with Windows Nearby Connections

[rajendrasp]

Project

Nearby Connections

Language

C++

OS Platform

Windows

What happened?

I have setup the Nearby Connections library on Windows. It is building fine and I am able to StartDiscovery. However in the logs, it gives me following message when it finds my phone -

I0129 00:54:09.772869 46244 p2p_cluster_pcp_handler.cc:224] OnePlus Nord doesn't have any endpoint id, discarding.
I0129 00:54:09.772869 46244 p2p_cluster_pcp_handler.cc:274] Found unrecognized BluetoothDeviceName OnePlus Nord

I am trying with Nearby share from Android and why does it not have an endpoint id?
Would I be able to integrate the sample app created on Windows with Nearby share from Android?

What did you expect to happen?

My phone to get discovered on my Windows app which is using Nearby Connections library.

How can we reproduce it (as minimally and precisely as possible)?

I am trying with integrating the Connections library in a Windows app.

How often does this bug happen?

Every time

Standalone code to reproduce the issue

No response

Relevant log output

No response

Anything else we need to know?

No response

[bourdakos1]

Hey @rajendrasp, glad to hear you were able to get Nearby Connections building/running on Windows, that’s awesome!

In order to discover Android devices running Nearby Share on Windows, you’d need to use the same service ID for discovery as Nearby Share. I’m not sure what service ID Nearby Share uses, but if you search the ChromeOS codebase you should be able to find it. Additionally, the Android device will need to be in the “everyone” discoverability mode.

I should mention that even if you discover Android devices with Nearby Connections, it will be difficult to send data. Since Nearby Share uses a custom packet format, you won’t simply be able to send files. I recommend making your own app that uses Nearby Connections on Android if you need to be able to also send data.

As a side note, would you be interested in contributing your work to get Windows building? I think it would help a lot of other people 😊

[rajendrasp]

Thank you @bourdakos1 for your response. I would love to contribute my work to get this building on Windows. It was a long trail of errors to fix. And I agree it would help many others.
But I have few items to nail down.
I would like to understand more about getting my Windows app to work with Google Nearby Share that comes out of the box on Android devices.
You mention ChromeOS. Is this the code you are talking about? Any pointers there would help. https://source.chromium.org/chromium/chromium/src/+/main:chrome/services/sharing/nearby/nearby_connections.cc
You also mention that Neaby Share uses a custom packet format. Any more info on that? Is that open source?

[bourdakos1]

Looks like the Nearby Share source is also being added to this repo. You can find the service ID here:

nearby/sharing/nearby_connections_manager_impl.cc

Line 58 in 9be93ae

constexpr char kServiceId[] = "NearbySharing";

[rajendrasp]

Thanks for pointing to this.
I tried with this service id but no luck.
When I am using this service id, I notice that there are peripheral devices getting discovered. For example, I see following log -

I0131 16:54:12.954299 38132 client_proxy.cc:330] ClientProxy [Endpoint Found]: [enter] id=E6AS; service=NearbySharing; info=325cc78f0e172a8d2faaf1373ddcb03a70; medium=BLE
Found endpoint E6AS on service NearbySharing

But for my phone, follwing is the data discovered - (code location)

It also discovered another device with follwoing info -

Is that the issue in Windows implementation or the advertising part?

[bourdakos1]

It sounds like it was able to discover a Nearby Share device, but the "OnePlus Nord" bluetooth advertisement in your screenshot doesn't look to be an advertisement from Nearby Share

[rajendrasp]

Is there a Android version requirement on Phone for Nearby share? Mine is Android 12.
So if this is not Nearby Share advertisement, then it might be normal Bluetooth advertisement from phone.

[rajendrasp]

I tried capturing the bluetooth traffic incoming from the phone using Wireshark on PC . It does not show NearbyShare advertisement. All the packets were like below -
Nearby Share will use "Bluetooth address" to advertise right?
What is the missing piece here?

Bluetooth HCI Event - Extended Inquiry Result
Event Code: Extended Inquiry Result (0x2f)
Parameter Total Length: 255
Number of responses: 1
BD_ADDR: OnePlusTechn_38:eb:e9 (ac:5f:ea:38:eb:e9)
Page Scan Repetition Mode: R1 (0x01)
Reserved: 0x00
Class of Device: 0x5a020c (Phone:Smartphone - services: Networking Capturing ObjectTransfer Telephony)
0000 11.. = Minor Device Class: Smartphone (0x03)
.... ..00 = Format Type: 0x0
0... .... .... .... = Major Service Classes: Information: False
.1.. .... .... .... = Major Service Classes: Telephony: True
..0. .... .... .... = Major Service Classes: Audio: False
...1 .... .... .... = Major Service Classes: Object Transfer: True
.... 1... .... .... = Major Service Classes: Capturing: True
.... .0.. .... .... = Major Service Classes: Rendering: False
.... ..1. .... .... = Major Service Classes: Networking: True
.... ...0 .... .... = Major Service Classes: Positioning: False
.... .... 0... .... = Major Service Classes: Reserved: 0x0
.... .... .0.. .... = Major Service Classes: LE Audio: 0x0
.... .... ..0. .... = Major Service Classes: Limited Discoverable Mode: False
.... .... ...0 0010 = Major Device Class: Phone (0x02)
.000 0111 0010 1100 = Clock Offset: 0x072c
RSSI: -62 dBm
Extended Inquiry Response Data
Device Name: OnePlus Nord
Length: 13
Type: Device Name (0x09)
Device Name: OnePlus Nord
16-bit Service Class UUIDs
Length: 23
Type: 16-bit Service Class UUIDs (0x03)
UUID 16: OBEX Object Push (0x1105)
UUID 16: Audio Source (0x110a)
UUID 16: A/V Remote Control Target (0x110c)
UUID 16: A/V Remote Control (0x110e)
UUID 16: Headset - Audio Gateway (0x1112)
UUID 16: PANU (0x1115)
UUID 16: NAP (0x1116)
UUID 16: Handsfree Audio Gateway (0x111f)
UUID 16: Phonebook Access - PSE (0x112f)
UUID 16: PnP Information (0x1200)
UUID 16: Message Access Server (0x1132)
32-bit Service Class UUIDs
Length: 1
Type: 32-bit Service Class UUIDs (0x05)
128-bit Service Class UUIDs
Length: 129
Type: 128-bit Service Class UUIDs (0x07)
Custom UUID: 00000000-0000-0000-0000-000000000000 (Unknown)
Custom UUID: 00000000-0000-0000-0000-000000000000 (Unknown)
Custom UUID: 00000000-0000-0000-0000-000000000000 (Unknown)
Custom UUID: 00000000-0000-0000-0000-000000000000 (Unknown)
Custom UUID: 00000000-0000-0000-0000-000000000000 (Unknown)
Custom UUID: 00000000-0000-0000-0000-000000000000 (Unknown)
Custom UUID: 00000000-0000-0000-0000-000000000000 (Unknown)
Custom UUID: 00000000-0000-0000-0000-000000000000 (Unknown)
Unused

[bourdakos1]

You can search for "Nearby Share" in the setting of your phone. Make sure Nearby Share is turned on and has its visibility set to "everyone"

[rajendrasp]

ok, so phone is discovered and connection accepted by phone from my console app when Google Nearby share is running on my windows pc where console app is running. Phone sends a disconnect message when connection is established. And payload transfer does not happen. I am attaching the log below -
When tried to send file from Phone to app, there also it connects and starts the transfer. But disconnect after getting first packet.

logss.txt

[bourdakos1]

Oh yes, I forgot to mention, your phone will need to be "nudged" into a discoverable mode. This can either be done by starting discovery on another device (in this case it was your Windows PC) or by using the "Files by Google" app and clicking "Receive" in the "Nearby Share" section of the app.

Nearby Share will disconnect if you send payloads that don't follow Nearby Share's custom packet format.

[rajendrasp]

thanks. Just to confirm since this will mostly need building ./sharing folder for windows as well which is bit of work.
are you talking about following custom format -

nearby/sharing/proto/wire_format.proto

Line 134 in 6ad4bf7

message Frame {

nearby/sharing/nearby_sharing_decoder_impl.cc

Line 35 in 6ad4bf7

std::unique_ptr<Frame> NearbySharingDecoderImpl::DecodeFrame(

Going through the code, I see that it sends an introduction frame first and then the payload. I will need to match what it looks for in the receiving part of code. do you have any documentation on the ./sharing code?

[rajendrasp]

Hi, I am trying to figure out the custom packet format and it is requiring me to add a lot of dependent code from ./sharing folder to my project. Right now, I am stuck at resolving the dependency of PublicCertificateDatabase.

nearby/sharing/internal/api/public_certificate_database.h

Line 28 in f8c907a

class PublicCertificateDatabase {

1. Can I skip paired key verification on both mobile and my console app?
2. If not, how do I resolve PublicCertificateDatabase dependency? I did not see this in Chromium codebase as well. In general, I did not find the implementation of anything inside \sharing\internal\api. Is that code not yet added to the repo?

[bourdakos1]

Yes, you can skip the certificate stuff. That's just used for contacts/self share.

[rajendrasp]

Looking at the code, looks like it needs certificate stuff -

nearby/sharing/nearby_sharing_service_impl.cc

Line 3213 in f8c907a

GetCertificateManager()->GetDecryptedPublicCertificate(

nearby/sharing/nearby_sharing_service_impl.cc

Line 3431 in f8c907a

RunPairedKeyVerification(

How do I skip it? If I own both apps, I can skip the flow but I need to communicate with Google's Nearby share on Android device.

[rajendrasp]

This part of code also does not make sense -

nearby/sharing/paired_key_verification_runner.cc

Line 309 in f8c907a

std::vector<nearby::sharing::proto::PublicCertificate> certificates;

There is no action on receiving end when cert info is received -

nearby/sharing/nearby_sharing_service_impl.cc

Line 4048 in f8c907a

void NearbySharingServiceImpl::HandleCertificateInfoFrame(

How can I send my public cert to my mobile device and have Nearby Share use it?

It says that it is to be shared offline. How is that shared offline?

nearby/sharing/proto/wire_format.proto

Line 295 in f8c907a

// A package containing certificate info to be shared to remote device offline.

[bourdakos1]

The certificate part isn't open source. You won't be able to build ./sharing without it, but if you manually write/parse frames, it can be skipped. If you don't use certificates, your app will just function as "everyone" mode in Nearby Share. Other devices will always be able to discover your app, but you will only be able to discover NS devices if they set their visibility to "everyone".

[rajendrasp]

Thank you @bourdakos1 ! I am able to successfully transfer the file to phone from my app. Really appreciate your help in resolving the issues along the way!
One question - when I use Google Quick share Windows app, I do not need to go to Files app on Android and start Receive part. Can I achieve that from my Windows app? How can my phone be "nudged" into a discoverable mode without having to open Files app or any other app on Phone?

[bourdakos1]

Yay!!

You can use a fast initiation advertisement to nudge the other device:

nearby/sharing/fast_initiation/nearby_fast_initiation_impl.cc

Line 107 in 88064b1

void NearbyFastInitiationImpl::StartAdvertising(

[rajendrasp]

I see that fast initiation implementation is also missing in ./sharing folder. E.g. FastInitiationManager implementation is not available.
I saw fast initiation advertiser implementation here - https://chromium.googlesource.com/chromium/src/+/refs/heads/main/chrome/browser/nearby_sharing/fast_initiation/fast_initiation_advertiser.cc

which has dependency on adapter which looks like this -

https://source.chromium.org/chromium/chromium/src/+/main:device/bluetooth/bluetooth_adapter_winrt.h

Do you think this is what would be needed for fast initiation on Windows?

Also, to confirm, it is the fast initiation advertisement from the sender which nudges the other device; is that correct? Can you share any details how that works?

[bourdakos1]

Windows only needs the fast init advertiser to function, and correct, the advertisement is from the sender which nudges the other device.

[rajendrasp]

I came across this documentation of this library. https://github.com/grishka/NearDrop/blob/master/PROTOCOL.md
Do you know if this is accurate? It would help to have something official by the authors of the library.

[bourdakos1]

Looks semi correct. However, I don’t recall the exact advertisement format off the top of my head.

[aditya-mankal]

Hello @bourdakos1, hope you are doing well! @rajendrasp and I have worked on setting up Google Nearby on Windows. While he is occupied elsewhere, I will be working on the fast initiation advertiser.

Can you please tell help me with exact advertisement format? My plan is to broadcast it using a quick piece of code before investing in integrating Fast Initiation into our current fork of Google Nearby.

Thank you!

[aditya-mankal]

Hello @bourdakos1, hope you are doing well!
Looking forward to your inputs on fast initiation. Knowing the exact BLE broadcast to nudge the Android devices into receive mode will greatly improve the user experience for my project. Thank you!

[bourdakos1]

I think you should be able to hardcode the advertisement to these values:

• Service UUID: 0xFE2C
• Service data: 0xFC128E0042