This is just a very short message to say that I have enhanced the "dechap" tool mentioned in my previous post. In addition to the original PPPoE support it can now extract and attack CHAP authentications sniffed from RADIUS and L2TPv2 protocols.
The syntax remains exactly the same and it should "just work". The code is available to download at https://www.github.com/theclam/dechap. Please post a comment if you have any feedback or suggestions.