General Block Transfer (GBT) dosen't work for encrypted push messages

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By pramodahanya , 12 December, 2018
Forums
Gurux DLMS for Java

I am using Gurux to read COSEM messages from an electric meter. Whenever the meter sends cyphered GBT messages the library treats each message as a complete message instead of waiting for the complete block transfer.
In my listener class extends GXDLMSSecureNotify implements IGXMediaListener, AutoCloseable, InitializingBean. In "onReceived" function when I call the "getdata" function to extract GXDLMSData from the reply, it goes to "GXDLMS.getPdu" reads the command as 224(GENERAL_BLOCK_TRANSFER) and the if condition in line 3028(GXDLMS) fails hence the handleGbt function in line 3031 is never called.
Below are the values at the if condition in line 3031:
data.getXml() = null
settings.isServer() = true
data.getMoreData().getValue() = 0
RequestTypes.FRAME.getValue() = 2

when I check data.isComplete() && !data.isMoreData() after calling "getData" method in my listner it always returns true even if there is more data.
For example, when I send On Installation push message I get 4 packets of length (115B*3 and 55B). the condition data.isComplete() && !data.isMoreData() is true for all the packets.
Is this a bug or am I doing something wrong?

pramodahanya

7 years 6 months ago

When I copy paste the received bytes in the Gurux DLMS Translator it shows Last block: true for the last block message. Is there any way to extract this info from the Gurux DLMS java library.

"<GeneralBlockTransfer>
<!--Last block: true-->
<!--Streaming: false-->
<!--Window size: 0-->
<BlockControl Value="128" />
<BlockNumber Value="3" />
<BlockNumberAck Value="0" />
<BlockData >"

pramodahanya

7 years 6 months ago

I have sent you an email with trace data. I have tried with V2.2.19 and I still have the problem.

pramodahanya

7 years 5 months ago

Hi Mikko,
I took the new code from GitHub. The new code is not even receiving the push messages.
I also tried by changing the client id from 1 to 102 "client = new GXDLMSClient(true, 1, 102, Authentication.NONE, null, InterfaceType.WRAPPER);" but still the "onReceived" method is not executed. In Wireshark, I could see the packets for TCP connection from the meter but no reply sent.
From the old code, I was able to receive the messages and parse them if the whole message was in a single packet. If GBT is used then I couldn't parse the messages.

BR,
Pramod

tallbada

2 years 5 months ago

Hi
I have the same problem like pramodahanya in his last message.
In Wireshark, I could see the packets for TCP connection from the meter but no data receive. In non-encrypted association (low) the gbt work well.

If you have any idea.
Regards.