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Software components for data protection, secure storage and transfer

Strange rx behavior

Also by EldoS: Rethync
The cross-platform framework that simplifies synchronizing data between mobile and desktop applications and servers and cloud storages
Posted: 05/06/2010 07:27:23
by neil young (Standard support level)
Joined: 11/05/2007
Posts: 96

Hi again,


Server A: The SBB Stack is driven in TLS mode.

Client B: In order to provoke some erroneous condx I'm sending non TLS packets from the client using the same SBB stack, but client.enabled = false

Client opens the socket connection and starts the initial sequence. Server is receiving raw socket data and calls DataAvailable. I'm immediately getting a OnReceive callback, requesting 2 bytes (which are written). The next and all subsequent callbacks OnReceive have a MaxSize of 0, which did hang in my realisation until now, because I wasn't prepared to get a callback of 0 bytes.

I can fix this, but why do I'm getting a 0 byte request?

Posted: 05/06/2010 08:19:43
by Ken Ivanov (EldoS Corp.)

Thank you for contacting us.

That is how it works. The server obtains packet length from first two bytes received. If this length is 0, 0 bytes are requested with the subsequent OnReceive call.

I agree that this behavior is a bit non-obvious. We will improve the behavior of the components to make them return errors in such cases.
Posted: 05/06/2010 09:30:38
by neil young (Standard support level)
Joined: 11/05/2007
Posts: 96

Length is in the first two bytes? Is this TLS standard?
Posted: 05/06/2010 09:41:27
by Ken Ivanov (EldoS Corp.)

It is defined by SSL2 standard. All SSL2+SSL3+TLS1-compliant clients must use SSL2 client hello for backward compatibility reasons.
Posted: 05/06/2010 11:09:37
by neil young (Standard support level)
Joined: 11/05/2007
Posts: 96

Ah, yes. Now when you say this I remember to have seen the "Client Hello" in some traces :)

Also by EldoS: CallbackFilter
A component to monitor and control disk activity, track file and directory operations (create, read, write, rename etc.), alter file data, encrypt files, create virtual files.



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