I'm trying to get a GATT client working on a Linux system that's running BlueZ 5.19. Unfortunately, neither Python or glib are available on this system, so my only choice is using libdbus. And did I mention that I've never used D-Bus before? I have a GATT server on another system that provides and advertises a custom service by its 16-byte UUID. I'm trying to get my BlueZ-based system to access this service. I've verified that I can discover the server by the UUID that it advertises, and I can get BlueZ to connect to it. My client app has successfully called Bluez's RegisterProfile method, passing the UUID advertised by the server, but BlueZ never calls my NewConnection method. In the options of the RegisterProfile call, I'm setting "Role" to "client", "AutoConnect" to TRUE, and both "RequireAuthorization" and "RequireAuthentication" to FALSE. I am running bluetoothd with the -E (experimental) option.
If I run bluetoothd in the foreground with both the -E and debug option, this is what I see when I start my client app:
bluetoothd[2126]: src/profile.c:register_profile() sender :1.20
bluetoothd[2126]: src/profile.c:create_ext() Created "myRemoteControlProfile"
bluetoothd[2126]: src/profile.c:ext_device_probe() myRemoteControlProfile probed with UUID 119649b6-b656-22ae-e611-ba85a04effc5
bluetoothd[2126]: src/service.c:change_state() 0x950d0: device 24:71:89:09:AD:09 profile myRemoteControlProfile state changed: unavailable -> disconnected (0)
"myRemoteControlProfile" is the name of the profile I registered with Bluez, "119649b6-b656-22ae-e611-ba85a04effc5" is the UUID that I passed in the RegisterProfile call and 24:71:89:09:AD:09 is the GATT server I'm trying to interact with, so BlueZ seems to know that this remote device provides the service I'm looking for. When I watch on the server device, I never see BlueZ connecting to it. Isn't BlueZ supposed to connect to a device when it sees that the device offers the service that I passed in RegisterProfile? Why don't I get a NewConnection method call? What does it mean that my registered profile never gets past the "disconnected" state? I know that the GATT API was still considered experimental in BlueZ 5.19; should I even expect this to work? Thanks!
BTW, this problem is nearly identical to the one described in https://stackoverflow.com/questions/36480516/bluez5-37-org-bluez-profilemanager1-registerprofile-cant-detect-green-throttle . Unfortunately, no answers were offered there.
I've been able to work around this problem by upgrading to BlueZ 5.43. I still don't get a NewConnection method call, but if I detect the remote device by the UUID of the service it advertises and connect to it manually, all of the characteristics of the service now appear when I do GetManagedObjects on org.bluez, which didn't happen in BlueZ 5.19.
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First post! Full disclosure, I have a very limited programming / pi background.
I'm working on a project to communicate with a Chroma Bi-Directional power supply (Model #: 62180D-1200) using LXI / SCPI communication. There's more I hope to do in the future, but for the time being I'm simply trying to establish a working communication channel using the "*IDN?" identify command. I have a raspberry pi connected to the same network as the power supply, which I am using to communicate to the 62180D.
Before beginning any of this testing, I have been able to establish that I can communicate with the device via http (web browser). The web page for the device even includes an scpi query tool -- which works!
Successful HTTP communication
To query the device from the pi I have used PuTty to log in to my pi and issue the following command:
lxi scpi -a <device ip address> "*IDN?"
I am expecting to see the same result as shown in the image above (Model No. , Serial No., Firmware Version), but instead I'm receiving the following:
Error: Read error (timeout)
Error: Failed to receive message
I was under the impression that this protocol is fairly plug and play. I have other LXI enabled devices on the same network that I am able to communicate with them using this same approach. Is there some obvious thing I'm missing here?
I see its adding a file to /var/lib/bluetooth/hci MAC/cache/ for each discovered device with its name as the address. Documentation says its creating device objects. Where and what are they, virtual dbus objects? ( ex: /dev_F8:41:1B:6B:95:2A). I know the device is removed after 3 minutes if not connected. And what else is it doing to make a device available for connecting with the bluez dbus interface. Thanks.
Bluetoothctl uses the Bluez DBus apis to do everything it does. When you do 'scan on' in bluetoothctl, it will call the StartDiscovery method of the Adapter object. Internally the Dbus will use the HCI interface to start a lescan. Once advertisement come in, Bluez will create objects for them on the Dbus and will send an InterfaceAdded or PropertiesChanged signals on the Dbus. Your application can listen to those signals which contain the address of the objects they are about.
I am running a BLE beacon in bluez5.52 on a linux machine(ubuntu 14.04) using the default gatt-service and the beacon using the btmgmt provided in the tools folder. Following are the commands I run to setup the beacon:
Terminal 1:
./gatt-service
Terminal 2
sudo ./btmgmt
add-adv -u 180d -u 180f -d 080954657374204C45 1
I am easily able to connect and disconnect with the beacon using BLE scanner app in android.
What I would like to do is setup a password for the beacon so that I am the only one who can connect to it. So far I have been unable to find any resources online that could help set that up. I have a decent understanding of the btmgmt and gatt-service code. I am looking for direction on what part of bluez code to look for to set up the password protection. Any leads, pseudo-code or partial code would help a lot.
Emil already mentioned pairing and bonding in the comments. This would definetly serve your purpose as you would be able to control who could connect to your peripheral.
A BLE characteristic can ask a connected device to authenticate before reading or writing which would result in a 'insufficient authentication error' if the device is not paired to your peripheral. A Android app is able to handle this error by displaying a pairing popup depending on the used pairing method.
So it is possible to have characteristics without security right next to one's that require pairing.
In case you still want to implement something like your mentioned password safety you should look into a 'authorized read'.
A characteristic which requires authorization first receives a read request and you can allow or deny it based on your own requirements. That means you can authorize yourself by sending a password to one characteristic and afterwards allow a read request on another characteristic. This would be even easier if you only accept one connection at a time.
I'm using BlueZ 5.49 and trying to connect, pair, and pass information between two different bluetooth devices.
It's seems like i have problem with enforcing security and authentication between the two.
I'm configuring each hci device with:
hciconfig hci0 pscan auth encrypt which as i read, is setting the device to security mode 3.
In addition i'm creating manualy this path in both sides: /var/lib/bluetooth/<local_bdaddr>/<remote_bdaddr>/info with LinkKey.
I've noticed that if i'm creating the path for only one device, and then trying to connect using rfcomm connect from the device without the infofile, the connection succeed, even though the device is lacking the info file which containts the LinkKey.
If i'm trying rfcomm connect from the device with the info file i'm getting Key Exchange Error, which is acceptable since the other device doesn't have the key.
My base line is that it seems that security and authentication are not enforced.
Many Thanks,
Liad
Apparently hci device is by default set to work in Secure Simple Pairing also known
as sspmode. Simple Pairing originaly generated to support devices that can't insert pin code during pairing process (such as headset).
Hence when a device is in sspmode enabled, it use a default pin key - say 0000, and then based on the pin, generating LinkKey to encrypt and authenticate, and thus not truely enforcing authentication as i mentioned before.
The line hciconfig hci0 sspmode disable is disabling the Secure Simple Pairing mode, and finally enforce authentication using the static LinkKey you supply
in the info file which located in /var/lib/bluetooth/<your_mac>/<remote_mac>/info.
I need to develop an application with a bluetooth dongle that makes use of the thermometer profile. The thing is that, after succesfully pair and connect with the remote device, whenever I try to run the test-therometer file, I obtain the following error:
dbus.exceptions.DBusException: org.freedesktop.DBus.Error.UnknownMethod: Method "RegisterWatcher" with signature "s" on interface "org.bluez.ThermometerManager1" doesn't exist
I have also tested the test-heartrate, and I obtain something similar:
dbus.exceptions.DBusException: org.freedesktop.DBus.Error.UnknownMethod: Method "RegisterWatcher" with signature "s" on interface "org.bluez.HeartRateManager1" doesn't exist
I have successfully tested the dongle with bluetoothctl, so I can discard hardware compatibility issues. I'd like to know if I'm missing something while running the tests.
I'm working under ArchLinux x86_64.