[gnutls-devel] [gnutls-help] DTLS-SRTP's send/recv API of gnutls

[Martin Storsjö]

Hi Nikos,

On Thu, 30 Jul 2015, Nikos Mavrogiannopoulos wrote:

> Hi,
> There are no SRTP packet handling functions in gnutls now. However,
> I'm already considering adding ESP packet handling in gnutls, so it
> would make sense to consider adding SRTP as well. Martin what do you
> think? Could the SRTP functions that you use be ported in gnutls?

The SRTP routines I use would probably be pretty easy to adapt into 
gnutls:

https://git.libav.org/?p=libav.git;a=blob;f=libavformat/srtp.h
https://git.libav.org/?p=libav.git;a=blob;f=libavformat/srtp.c

This shouldn't have much actual dependencies on the surrounding libraries; 
it only uses some generic AES encryption/decryption, HMAC, base64 and 
endian independent reading/writing of integers.

Since I'm the only author of these files, I can relicense it to the 
license used by gnutls if you want to, to help integration.

The only thing missing here is the glue for mapping the value returned by 
gnutls_srtp_get_selected_profile to strings to pass to ff_srtp_set_crypto, 
but that is pretty much trivial.

// Martin