Hello all,
I am participating in an effort to make use of the BlueZ libraries to pull
data from Bluetooth Low Energy health devices.
We are working with the 5.8 version of the library, kernel version 3.12.9,
bluetoothctl, and gatttool when we encountered a possible error.
We expected on the reconnection of two bonded devices, one of which had
stored measurements, that data would transfer. When running gatt tool in
medium security the first measurement to be indicated was lost.
First we used Bluetooth control to pair with the simulated agent device (a
thermometer). Then we disconnected with bluetoothctl and connected with
gatttool in order to write to the C3D (client characteristic configuration
descriptors). After setting the C3D to indicate, we transferred a
measurement successfully. Up until this point we saw no unexpected
difference in behavior between low and medium security on the gatttool.
However upon attempting to reconnect to the simulated agent device with
medium security two unexpected behaviors occurred. First, and more
immediately apparent was that the simulated agent did not receive a
confirmation of the indication. A slightly closer look using the hcidump,
trying to find what had happened, showed that the indication had arrived at
the hci layer but was not received at events_handler. While the indication
is sent very swiftly upon the reconnection of the devices we understand this
to be the manner in which low energy devices are supposed to behave given
stored measurements and a bonded device.
Records of hcidumps are attached.
Caleb Reinhold
P.S. Resending after failing to attach traces
< HCI Command: LE Create Connection (0x08|0x000d) plen 25 [hci0] 5199.285444
Scan interval: 60.000 msec (0x0060)
Scan window: 30.000 msec (0x0030)
Filter policy: White list is not used (0x00)
Peer address type: Public (0x00)
Peer address: 00:02:72:C6:A0:6B (CC&C Technologies, Inc.)
Own address type: Public (0x00)
Min connection interval: 50.00 msec (0x0028)
Max connection interval: 70.00 msec (0x0038)
Connection latency: 0x0000
Supervision timeout: 420 msec (0x002a)
Min connection length: 0.000 msec (0x0000)
Max connection length: 0.000 msec (0x0000)
> HCI Event: Command Status (0x0f) plen 4 [hci0] 5199.288196
LE Create Connection (0x08|0x000d) ncmd 1
Status: Success (0x00)
> HCI Event: LE Meta Event (0x3e) plen 19 [hci0] 5209.096157
LE Connection Complete (0x01)
Status: Success (0x00)
Handle: 64
Role: Master (0x00)
Peer address type: Public (0x00)
Peer address: 00:02:72:C6:A0:6B (CC&C Technologies, Inc.)
Connection interval: 67.50 msec (0x0036)
Connection latency: 0.00 msec (0x0000)
Supervision timeout: 420 msec (0x002a)
Master clock accuracy: 0x05
@ Device Connected: 00:02:72:C6:A0:6B (1) flags 0x0000
> ACL Data RX: Handle 64 flags 0x02 dlen 19 [hci0] 5209.129475
ATT: Handle Value Indication (0x1d) len 14
Handle: 0x0004
Data: 0363000000de0702030f1b0e
< ACL Data TX: Handle 64 flags 0x00 dlen 5 [hci0] 5209.129824
ATT: Handle Value Confirmation (0x1e) len 0
> HCI Event: Number of Completed Packets (0x13) plen 5 [hci0] 5209.338106
Num handles: 1
Handle: 64
Count: 1
< HCI Command: Disconnect (0x01|0x0006) plen 3 [hci0] 5258.609760
Handle: 64
Reason: Remote User Terminated Connection (0x13)
> HCI Event: Command Status (0x0f) plen 4 [hci0] 5258.611935
Disconnect (0x01|0x0006) ncmd 1
Status: Success (0x00)
> HCI Event: Disconnect Complete (0x05) plen 4 [hci0] 5258.674959
Status: Success (0x00)
Handle: 64
Reason: Connection Terminated By Local Host (0x16)
@ Device Disconnected: 00:02:72:C6:A0:6B (1) reason 2
< HCI Command: LE Create Connection (0x08|0x000d) plen 25 [hci0] 5302.994402
Scan interval: 60.000 msec (0x0060)
Scan window: 30.000 msec (0x0030)
Filter policy: White list is not used (0x00)
Peer address type: Public (0x00)
Peer address: 00:02:72:C6:A0:6B (CC&C Technologies, Inc.)
Own address type: Public (0x00)
Min connection interval: 50.00 msec (0x0028)
Max connection interval: 70.00 msec (0x0038)
Connection latency: 0x0000
Supervision timeout: 420 msec (0x002a)
Min connection length: 0.000 msec (0x0000)
Max connection length: 0.000 msec (0x0000)
> HCI Event: Command Status (0x0f) plen 4 [hci0] 5302.996878
LE Create Connection (0x08|0x000d) ncmd 1
Status: Success (0x00)
> HCI Event: LE Meta Event (0x3e) plen 19 [hci0] 5311.264930
LE Connection Complete (0x01)
Status: Success (0x00)
Handle: 64
Role: Master (0x00)
Peer address type: Public (0x00)
Peer address: 00:02:72:C6:A0:6B (CC&C Technologies, Inc.)
Connection interval: 67.50 msec (0x0036)
Connection latency: 0.00 msec (0x0000)
Supervision timeout: 420 msec (0x002a)
Master clock accuracy: 0x05
< HCI Command: LE Start Encryption (0x08|0x0019) plen 28 [hci0] 5311.265128
Handle: 64
Random number: 0d996e4936b9603f
Encryption diversifier: 0x13a1
Long term key: d43f4e489cc5b0746f86eac218c976e9
@ Device Connected: 00:02:72:C6:A0:6B (1) flags 0x0000
> HCI Event: Command Status (0x0f) plen 4 [hci0] 5311.267895
LE Start Encryption (0x08|0x0019) ncmd 1
Status: Success (0x00)
> ACL Data RX: Handle 64 flags 0x02 dlen 19 [hci0] 5311.326262
ATT: Handle Value Indication (0x1d) len 14
Handle: 0x0004
Data: 0363000000de0702030f1c38
> HCI Event: Encryption Change (0x08) plen 4 [hci0] 5311.730919
Status: Success (0x00)
Handle: 64
Encryption: Enabled with AES-CCM (0x01)
< HCI Command: LE Create Connection (0x08|0x000d) plen 25 [hci0] 5302.994402
Scan interval: 60.000 msec (0x0060)
Scan window: 30.000 msec (0x0030)
Filter policy: White list is not used (0x00)
Peer address type: Public (0x00)
Peer address: 00:02:72:C6:A0:6B (CC&C Technologies, Inc.)
Own address type: Public (0x00)
Min connection interval: 50.00 msec (0x0028)
Max connection interval: 70.00 msec (0x0038)
Connection latency: 0x0000
Supervision timeout: 420 msec (0x002a)
Min connection length: 0.000 msec (0x0000)
Max connection length: 0.000 msec (0x0000)
> HCI Event: Command Status (0x0f) plen 4 [hci0] 5302.996878
LE Create Connection (0x08|0x000d) ncmd 1
Status: Success (0x00)
> HCI Event: LE Meta Event (0x3e) plen 19 [hci0] 5311.264930
LE Connection Complete (0x01)
Status: Success (0x00)
Handle: 64
Role: Master (0x00)
Peer address type: Public (0x00)
Peer address: 00:02:72:C6:A0:6B (CC&C Technologies, Inc.)
Connection interval: 67.50 msec (0x0036)
Connection latency: 0.00 msec (0x0000)
Supervision timeout: 420 msec (0x002a)
Master clock accuracy: 0x05
< HCI Command: LE Start Encryption (0x08|0x0019) plen 28 [hci0] 5311.265128
Handle: 64
Random number: 0d996e4936b9603f
Encryption diversifier: 0x13a1
Long term key: d43f4e489cc5b0746f86eac218c976e9
@ Device Connected: 00:02:72:C6:A0:6B (1) flags 0x0000
> HCI Event: Command Status (0x0f) plen 4 [hci0] 5311.267895
LE Start Encryption (0x08|0x0019) ncmd 1
Status: Success (0x00)
> ACL Data RX: Handle 64 flags 0x02 dlen 19 [hci0] 5311.326262
ATT: Handle Value Indication (0x1d) len 14
Handle: 0x0004
Data: 0363000000de0702030f1c38
> HCI Event: Encryption Change (0x08) plen 4 [hci0] 5311.730919
Status: Success (0x00)
Handle: 64
Encryption: Enabled with AES-CCM (0x01)
> ACL Data RX: Handle 64 flags 0x02 dlen 19 [hci0] 5556.355293
ATT: Handle Value Indication (0x1d) len 14
Handle: 0x0004
Data: 0363000000de0702030f2101
< ACL Data TX: Handle 64 flags 0x00 dlen 5 [hci0] 5556.355579
ATT: Handle Value Confirmation (0x1e) len 0
> HCI Event: Number of Completed Packets (0x13) plen 5 [hci0] 5556.622163
Num handles: 1
Handle: 64
Count: 1
