[OTR-dev] OTR Fragmenting Support

Ian Goldberg ian at cypherpunks.ca
Wed Apr 12 14:27:30 EDT 2006

On Wed, Apr 12, 2006 at 01:47:55PM -0400, Alex wrote:
> Hey. I created a patch for limited fragmenting support in libotr. It
> only works with in the AKE, but that's where many of the longest
> messages are sent. I have not modified the library to include support
> for data messages, as I do not know how the fragmented messages should
> be returned. to the application. Attached is a README and the patch. You
> can also download the patch at sourceforge:

A good start.  Thanks!

There are a few problems with it (mms is never initialized; your
fragments are too large (they don't take into account the size of the
header); you don't free memory properly in the event of an error; etc.),
but it's definitely in line with what was intended.

I probably won't get a chance to work on OTR too much until after the
Computers, Freedom, and Privacy conference (www.cfp2006.org), but I
should have some time after that.

Data messages are a little tricky, since it's unclear whether messages
sent with inject_message() will go out before or after the message left
in *messagep at the end of otrl_message_sending() [this will depend on
the structure of the application using libotr].  But I suppose all
fragments *could* be sent using inject_message().

   - Ian

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