Virtualized BLE testing setup

[Fristi]

Hello,

Lately we've got trouBLE running on HCI. I'm pretty new to the whole space, but I've found also btvirt to be included in the bluez-test-tools. This allows you to run a virtualized BLE environment. This could be useful for CI, testing and local development

I've tried setting this up on my MacOS via first QEMU (no experience) and later via Vagrant + Virtualbox. I've set up a Ubuntu 24.x virtual machine where I've installed bluez and bluez-test-tools

I wrote myself a README after the aforementioned steps.

1. After that you can vagrant up --provider=virtualbox .. this will boot up a machine with Ubuntu 24.x
2. You can login via vagrant ssh or output the vagrant ssh-config later which is handy in conjuction with the Justfile
3. After you are logged in run sudo apt-get update and sudo apt-get install bluez bluez-test-tools
4. This should installed the test tools like btvirt
5. In order to make this work you also need sudo modprobe hci_vhci
6. To have correct file permissions you need sudo chmod 666 /dev/vhci. Use ls -l /dev/vhci to verify it has correct permissions
7. Next you can create a virtual device by using btvirt -l2 &
8. Verify it's active hciconfig -a
9. In order to make it work with our Rust programs (central and this peripheral) you need to bring down sudo hciconfig hci{X} down

I've compiled the examples ble_bas_peripheral and ble_bas_central and ran them

sudo systemd-run --pty --uid=$(id -u) --gid=$(id -g)   --same-dir --setenv RUST_LOG=info --setenv PATH   --property "AmbientCapabilities=CAP_NET_ADMIN" ~/ble_bas_peripheral 0
Running as unit: run-u171.service
Press ^] three times within 1s to disconnect TTY.
[2025-12-23T12:38:01Z INFO  trouble_example_apps::ble_bas_peripheral] Our address = Address { kind: AddrKind(1), addr: BdAddr([255, 143, 26, 5, 228, 255]) }
[2025-12-23T12:38:01Z INFO  trouble_example_apps::ble_bas_peripheral] Starting advertising and GATT service
[2025-12-23T12:38:01Z INFO  trouble_host::host] [host] using packet pool with MTU 251 capacity 16
[2025-12-23T12:38:01Z INFO  trouble_host::host] [host] filter accept list size: 16
[2025-12-23T12:38:01Z INFO  trouble_host::host] [host] setting txq to 1, fragmenting at 192
[2025-12-23T12:38:01Z INFO  trouble_host::host] [host] configuring host buffers (1 packets of size 255)
[2025-12-23T12:38:01Z INFO  trouble_host::host] [host] initialized
[2025-12-23T12:38:01Z INFO  trouble_host::host] [host] Device Address 00:AA:01:00:00:00
[2025-12-23T12:38:01Z INFO  trouble_example_apps::ble_bas_peripheral] [adv] advertising

sudo systemd-run --pty --uid=$(id -u) --gid=$(id -g)   --same-dir --setenv RUST_LOG=info --setenv PATH   --property "AmbientCapabilities=CAP_NET_ADMIN" ~/ble_bas_central 1
Running as unit: run-u173.service; invocation ID: fbd88e8204a649c6825b3e6bfdd4568b
Press ^] three times within 1s to disconnect TTY.
[2025-12-23T12:38:14Z INFO  trouble_example_apps::ble_bas_central] Our address = Address { kind: AddrKind(1), addr: BdAddr([255, 143, 27, 5, 228, 255]) }
[2025-12-23T12:38:14Z INFO  trouble_example_apps::ble_bas_central] Scanning for peripheral...
[2025-12-23T12:38:14Z INFO  trouble_example_apps::ble_bas_central] Connecting
[2025-12-23T12:38:14Z INFO  trouble_host::host] [host] using packet pool with MTU 251 capacity 16
[2025-12-23T12:38:14Z INFO  trouble_host::host] [host] filter accept list size: 16
[2025-12-23T12:38:14Z INFO  trouble_host::host] [host] setting txq to 1, fragmenting at 192
[2025-12-23T12:38:14Z INFO  trouble_host::host] [host] configuring host buffers (1 packets of size 255)
[2025-12-23T12:38:14Z INFO  trouble_host::host] [host] initialized
[2025-12-23T12:38:14Z INFO  trouble_host::host] [host] Device Address 00:AA:01:01:00:01
[2025-12-23T12:38:14Z WARN  trouble_host::host] Error connection complete event: Connection Failed to be Established / Synchronization Timeout

thread 'main' panicked at /Users/markdejong/Projects/trouble/examples/apps/src/ble_bas_central.rs:44:51:
called `Result::unwrap()` on an `Err` value: BleHost(Timeout)
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

[Fristi]

After digging deeper I discovered that BlueZ virtualized doesn't like a peer_address of 00:00:00:00:00:00

ble_bas_central[41853]: < HCI Command: Reset (0x03|0x0003) plen 0                                                                                                      #1 [hci0] 19.952826
> HCI Event: Command Complete (0x0e) plen 4                                                                                                                            #2 [hci0] 19.953288
      Reset (0x03|0x0003) ncmd 1
        Status: Success (0x00)
ble_bas_central[41853]: < HCI Command: LE Set Random Address (0x08|0x0005) plen 6                                                                                      #3 [hci0] 19.953566
        Address: FF:E4:05:1B:8F:FF (Static)
> HCI Event: Command Complete (0x0e) plen 4                                                                                                                            #4 [hci0] 19.953624
      LE Set Random Address (0x08|0x0005) ncmd 1
        Status: Success (0x00)
ble_bas_central[41853]: < HCI Command: Set Event Mask (0x03|0x0001) plen 8                                                                                             #5 [hci0] 19.953705
        Mask: 0x200000000000809c
          Connection Complete
          Connection Request
          Disconnection Complete
          Encryption Change
          Hardware Error
          LE Meta
> HCI Event: Command Complete (0x0e) plen 4                                                                                                                            #6 [hci0] 19.953735
      Set Event Mask (0x03|0x0001) ncmd 1
        Status: Success (0x00)
ble_bas_central[41853]: < HCI Command: Set Event Mask Page 2 (0x03|0x0063) plen 8                                                                                      #7 [hci0] 19.954077
        Mask: 0x0000000002000000
          Unknown mask (0x0000000002000000)
> HCI Event: Command Complete (0x0e) plen 4                                                                                                                            #8 [hci0] 19.954965
      Set Event Mask Page 2 (0x03|0x0063) ncmd 1
        Status: Success (0x00)
ble_bas_central[41853]: < HCI Command: LE Set Event Mask (0x08|0x0001) plen 8                                                                                          #9 [hci0] 19.955027
        Mask: 0x0000000000031a57
          LE Connection Complete
          LE Advertising Report
          LE Connection Update Complete
          LE Long Term Key Request
          LE Data Length Change
          LE Enhanced Connection Complete
          LE PHY Update Complete
          LE Extended Advertising Report
          LE Extended Scan Timeout
          LE Extended Advertising Set Terminated
> HCI Event: Command Complete (0x0e) plen 4                                                                                                                           #10 [hci0] 19.955060
      LE Set Event Mask (0x08|0x0001) ncmd 1
        Status: Success (0x00)
ble_bas_central[41853]: < HCI Command: LE Read Accept List Size (0x08|0x000f) plen 0                                                                                  #11 [hci0] 19.955144
> HCI Event: Command Complete (0x0e) plen 5                                                                                                                           #12 [hci0] 19.955152
      LE Read Accept List Size (0x08|0x000f) ncmd 1
        Status: Success (0x00)
        Size: 16
ble_bas_central[41853]: < HCI Command: LE Read Buffer Size (0x08|0x0002) plen 0                                                                                       #13 [hci0] 19.955412
> HCI Event: Command Complete (0x0e) plen 7                                                                                                                           #14 [hci0] 19.955421
      LE Read Buffer Size (0x08|0x0002) ncmd 1
        Status: Success (0x00)
        Data packet length: 192
        Num data packets: 1
ble_bas_central[41853]: < HCI Command: Host Buffer Size (0x03|0x0033) plen 7                                                                                          #15 [hci0] 19.955665
        ACL MTU: 255  ACL max packet: 1
        SCO MTU: 0    SCO max packet: 0
> HCI Event: Command Complete (0x0e) plen 4                                                                                                                           #16 [hci0] 19.955676
      Host Buffer Size (0x03|0x0033) ncmd 1
        Status: Success (0x00)
ble_bas_central[41853]: < HCI Command: Read BD ADDR (0x04|0x0009) plen 0                                                                                              #17 [hci0] 19.955738
> HCI Event: Command Complete (0x0e) plen 10                                                                                                                          #18 [hci0] 19.955784
      Read BD ADDR (0x04|0x0009) ncmd 1
        Status: Success (0x00)
        Address: 00:AA:01:00:00:00 (OUI 00-AA-01)
ble_bas_central[41853]: < HCI Command: LE Clear Accept List (0x08|0x0010) plen 0                                                                                      #19 [hci0] 19.956082
> HCI Event: Command Complete (0x0e) plen 4                                                                                                                           #20 [hci0] 19.956108
      LE Clear Accept List (0x08|0x0010) ncmd 1
        Status: Success (0x00)
ble_bas_central[41853]: < HCI Command: LE Add Device To Accept List (0x08|0x0011) plen 7                                                                              #21 [hci0] 19.956163
        Address type: Random (0x01)
        Address: FF:E4:05:1A:8F:FF (Static)
> HCI Event: Command Complete (0x0e) plen 4                                                                                                                           #22 [hci0] 19.956171
      LE Add Device To Accept List (0x08|0x0011) ncmd 1
        Status: Success (0x00)
ble_bas_central[41853]: < HCI Command: LE Create Connection (0x08|0x000d) plen 25                                                                                     #23 [hci0] 20.958484
        Scan interval: 62.500 msec (0x0064)
        Scan window: 62.500 msec (0x0064)
        Filter policy: Accept list is used (0x01)
        Peer address type: Random (0x01)
        Peer address: 00:00:00:00:00:00 (Non-Resolvable)
        Own address type: Random (0x01)
        Min connection interval: 80.00 msec (0x0040)
        Max connection interval: 80.00 msec (0x0040)
        Connection latency: 0 (0x0000)
        Supervision timeout: 8000 msec (0x0320)
        Min connection length: 0.000 msec (0x0000)
        Max connection length: 0.000 msec (0x0000)
> HCI Event: Command Status (0x0f) plen 4                                                                                                                             #24 [hci0] 20.958680
      LE Create Connection (0x08|0x000d) ncmd 1
        Status: Success (0x00)
> HCI Event: LE Meta Event (0x3e) plen 19                                                                                                                             #25 [hci0] 20.958696
      LE Connection Complete (0x01)
        Status: Connection Failed to be Established (0x3e)
        Handle: 0
        Role: Central (0x00)
        Peer address type: Random (0x01)
        Peer address: 00:00:00:00:00:00 (Non-Resolvable)
        Connection interval: 0.00 msec (0x0000)
        Connection latency: 0 (0x0000)
        Supervision timeout: 0 msec (0x0000)
        Central clock accuracy: 0x00
ble_bas_central[41853]: @ USER Close: ble_bas_central   

If I remove the set accept filter list code and hardcode the peer_addr to the address used in the examples the communication between the peripheral and central is established!! https://github.com/embassy-rs/trouble/blob/main/host/src/central.rs#L44

According to ChatGPT, the spec mandates that if you use use_filter_accept_list in the connect, the peer_addr which is supplied should be ignored. I've been skimming through the bluez code, but couldn't find this logic yet.

Also the 0x3e status seems to come from https://github.com/bluez/bluez/blob/05813df5e490ab7a791bf4ec6f49c68142f24688/emulator/btdev.c#L4180

I also tried to run my own code which uses central.connect using a real BLE device and I've got the same error there. This code is also running the HCI stack, which might be related to this problem.

[Fristi]

Dropped the question at BlueZ as well https://github.com/orgs/bluez/discussions/1763