Subject: [Hipsec] Sending data on HIP packets

From: Robert Moskowitz <[email-masked]>
Date: Wed, 21 Apr 2010 11:17:00 -0400

Is there any experience in sending data along with I2 and R2?

Is this easy to do or very hard even with HIP aware apps?

Do we provide for carrying data here with 5201-bis?

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From: "Laganier, Julien" <[email-masked]>
Date: Wed, 21 Apr 2010 09:14:33 -0700

> Is there any experience in sending data along with I2 and R2?

I don't.
 
> Is this easy to do or very hard even with HIP aware apps?

Hmmm. Isn't this going to create problem with PMTUD because the PMTU on the data sent over I2 and R2 will be lower than can be expected after the HIP handshake concludes? On the other hand if the first sent is TCP SYN on I2 and TCP SYN ACK on R2 then there's no problem with PMTUD...

--julien

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From: Robert Moskowitz <[email-masked]>
Date: Wed, 21 Apr 2010 13:29:44 -0400

> Hmmm. Isn't this going to create problem with PMTUD because the PMTU on the data sent over I2 and R2 will be lower than can be expected after the HIP handshake concludes? On the other hand if the f…

The Initiator would have to 'know' that the data would fit within the 
allowed frame size.

The Responder (after validating I2 and setting up the HIP Association 
state) might just pass the data up the stack and immediate send R2 
without any data, the data response following later in its own datagram.

Or if the Responder 'knows' there should be a response, it holds off on 
sending R2 until it gets the data (typically a TCP SYN/ACK). In fact if 
the higher layer rejects the connection with a quite drop, the Responder 
could not even send R2 and quitely drop the Association as well.

Lots of room for smart behaviour. Or bad programming :)