Issue in l2cap test

[sandysparkz]

Hello Everyone, I'm currently testing the bluez tools like l2ping & l2test, So my intention was to interface between two devices through l2cap layer. I have cloned this repository on two raspberry pi devices, and made necessary configuration to execute those tools, but I didn't get the expected output instead the program stuck at socket level during connect stage on sender due to which the receiver waits on accept stage, also I tried this sample tools on two different systems(PC) got the similar results, can someone guide me on what I'm missing here.

Client
$  sudo ./tools/l2test -p  C5:86:1A:53:D7:3B
Can't connect socket: Host is down

Server
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*** Booting Zephyr OS build v4.1.0-1545-gfa45bebccfb1 ***
[00:00:00.255,462] <inf> bt_hci_core: HW Platform: Nordic Semiconductor (0x0002)
[00:00:00.255,493] <inf> bt_hci_core: HW Variant: nRF52x (0x0002)
[00:00:00.255,523] <inf> bt_hci_core: Firmware: Standard Bluetooth controller (0x00) Version 4.1 Build 99
[00:00:00.256,561] <inf> bt_hci_core: Identity: C5:86:1A:53:D7:3B (random)
[00:00:00.256,591] <inf> bt_hci_core: HCI: version 5.4 (0x0d) revision 0x0000, manufacturer 0x05f1
[00:00:00.256,622] <inf> bt_hci_core: LMP: version 5.4 (0x0d) subver 0xffff

[iagocq]

How strange to also stumble upon the same problem on a similar environment (Linux -> Zephyr). I'm trying to connect to an L2CAP server from a PC to an ESP32 with an AF_BLUETOOTH SEQPACKET BTPROTO_L2CAP socket, with no success. Same error: Host is down. The PC side also terminates the entire Bluetooth connection after failing to connect to the channel.

I tried with different client devices (WSL + bluetooth dongle, Torizon Linux on a Toradex) and servers (2 different ESP32s that had a listening L2CAP server; my phone and a TV that popped up on a scan that did not have a listening server). Each attempt failed the same way: Host is down, then right after that the Bluetooth connection is terminated by the client (BlueZ) side.

@sandysparkz did you ever figure out what was happening on your side?
I'm going to do more tests anyway.

[iagocq]

Things are looking better!

After searching around, my issue was that I was connecting without setting l2_bdaddr_type to one of BDADDR_LE_PUBLIC or BDADDR_LE_RANDOM, defaulting to BDADDR_BREDR, which attempted to create a BR/EDR connection and failed because all my attempts were with LE connections underneath. I still cannot establish a L2CAP connection (very likely my fault), but my ESP32 at least sees the attempt and rejects it, without BlueZ disconnecting from the device!

For your problem, @sandysparkz, did you try l2test with one of -V le_public or -V le_random? By default, it seems to attempt a BR/EDR connection.