[openssl-dev] Need Help with BIO callback and/or BIO filter chain

[Dr. Stephen Henson]

On Fri, Feb 20, 2015, W Smith wrote:

> Rich,
> 
> Yeah, I have industrial strength Tylenol standing by. I'm expecting this to be painful, but not insurmountable for the handshake. If I'm unable to even get at the ultimate source/sink, I can't get anywhere.
> 
> I can deal with the HTTP side and the plethora of application-specific and threading issues, but I'm lost on the BIO part. I'll take any pointers or suggestions you can offer.
> 

If I understand what you're trying to do I can see a couple of options.

One is to write your own BIO which looks like an "ordinary" BIO to the TLS
library but does all the translation under the hood. You could start with the
socket BIO and adapt it to your needs, making sure you handle non-blocking I/O
correctly.

The other is a BIO pair where this I/O can be handled at an application level
but you have to be careful to get everything right so there aren't any
deadlocks. You mentioned a BIO pair in the other message though. Are you
already using a BIO pair?

Steve.
--
Dr Stephen N. Henson. OpenSSL project core developer.
Commercial tech support now available see: http://www.openssl.org