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| GarryF |
 Posted: Fri Nov 16, 2001 4:41 am Post subject: |
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Newbie
Joined: 15 Nov 2001
Posts: 2
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Has anyone documentation on structure(s) in pAgentbuffer for MQClient Send/Receive exits? IBM docs I've seen refer to MQZQH which doesn't seem to be present. AgentBuffer have what appears to be StrucId= 'TSH ' followed by MQOD, MQMD, MQPMO structures. These are seen at different stages in three invocations for MQXR_XMIT for a single message.
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GarryF |
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| sfari |
| Posted: Wed Mar 17, 2004 12:39 am Post subject: |
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Centurion
Joined: 15 Apr 2003
Posts: 144
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| Hi Garry, I am looking for the same. I was searching the MQ documentation about the exact structure of messages and was not successful. Can you tell me where I can find documentation about how the message is structured? |
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| JasonE |
| Posted: Wed Mar 17, 2004 1:39 am Post subject: |
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Grand Master
Joined: 03 Nov 2003
Posts: 1220
Location: Hursley
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TSH's are transmission segment headers and are not publically documented outside of IBM (well, they shouldnt be!) - This is the flattened format of your message, or client api call, etc and handles the negotiation between different releases of MQ and flags regarding some state information, units of work etc.
I wouldnt go touching it unless you have an extremely good reason  |
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| sfari |
| Posted: Wed Mar 17, 2004 3:38 am Post subject: |
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Centurion
Joined: 15 Apr 2003
Posts: 144
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| Hi Jason, I don't want to touch the TSH. MQ passes a data buffer containing the whole message including TSH, MQMD, MQPMO, ... to the channel exit. What I am looking for is the exact offset of the specific attributes (eg. userID, messageLength, ...) for manipulating them. Is this documented somewhere? Or is it wrong to directly manipulate the data buffer? |
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| JasonE |
| Posted: Wed Mar 17, 2004 7:31 am Post subject: |
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Grand Master
Joined: 03 Nov 2003
Posts: 1220
Location: Hursley
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| Thats a good question I dont know the answer to. I assume for encryption or compression you treat the whole data as one, as long as the same data is returned after the exits have run on both ends. I havent heard of people changing data in the middle of the struture. Thats not to say it isnt done, I just dont think we document how... |
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| sfari |
| Posted: Wed Mar 17, 2004 11:55 pm Post subject: |
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Centurion
Joined: 15 Apr 2003
Posts: 144
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In my understanding it's not possible to to treat the whole data as one for encryption or compression. In order the message can still be puted on a queue it needs meaningful data in TSH, MQMD, MQPMO, ....
But to be able to touch only the content a programmer needs to know from which byte on the message content starts and where it can adapt the message length because this might change. |
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| sfari |
| Posted: Thu Mar 18, 2004 1:41 am Post subject: |
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Centurion
Joined: 15 Apr 2003
Posts: 144
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| The reason why I need to keep the message header valid as it comes into the exit, is that I am working on a End-To-End encryption. Which means I don't have a pair of send- and receive-exits on both end of the channel. In my situation one part of the send- receive exit pair is on the sender application and the other part on the receiver application. This means the message on the queue has an encrypted content but a clear header. |
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| sfari |
| Posted: Tue Jun 15, 2004 3:38 am Post subject: |
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Centurion
Joined: 15 Apr 2003
Posts: 144
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I am back and work on this issue again.
What I need is a end- to end-encryption between a Java MQ/JMS sender and a receiver client. It is a requirement that the content of the message stored on a queue has to be encrypted.
1. My Idea was to encrypt the message content in a send exit (of the Java sender application) and to leaf all the header infos MQ needs to store a message on a queue.
2. Then to decrypt the message content in a receive exit (of the Java receiver application).
This seems to be quite complex. One of the problems are segmented messages.
Is it a good idea to do this in this way? What alternatives do I have? API exits or message exits are not supported for Java, right? |
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| MichaelR |
| Posted: Tue Jun 22, 2004 12:49 pm Post subject: MQ Send/Recv Exits.... |
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Apprentice
Joined: 20 May 2002
Posts: 37
Location: Tampa
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SFari,
Perfoming encryption and decryption via Send/Recv Message Exits will not satisfy your requirment of having the messages encrypted on the queue.
Additionally, Send/Recv exits, as they are associated with MQ Channels, would not be processing any messages "MQPUT" locally.
While there are ways to do what you are asking, I don't think Send/Recv exits will satisfy your requirements.
Regards,
MichaelR |
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| cheanfeiy |
| Posted: Fri Jul 02, 2004 12:06 am Post subject: |
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Apprentice
Joined: 21 Jun 2003
Posts: 26
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SFari,
In order to have the
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| message stored on a queue has to be encrypted |
, you can try Data Convertion Exit.
Regards |
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