Subject: Re: Modifying Cryptography Code

From: Aidas Kasparas <[email-masked]>
Date: Tue, 06 Sep 2005 18:24:42 +0300

Alaa Dalghan wrote:
> imposes too much processing overhead on the linux VPN gateway. The
> required behavior is that the VPN gateway just RELAYS encrypted data
> (ESP envelopes) without decrypting them. This is impossible in the
> current ipsec implementation since"the end of a tunnel HAS ALWAYS to be
> decrypted".
> 

That can work only in case when you set esp's encryption keys manually
and the same on all 30 your clients. Also, SPIs should be the same. I
would not call such setup secure.

Better way is to put all these clients into single subnet and configure
them to require transport mode esp transformation in that subnet +
employ automatic keying and auth by certs. And required subset of these
scarry 900 tunnels will set up automatically. [Don't ask me how to
configure this setup in windows -- I don't know].

> I hope that someone can help me with finding this portion of the code
> and modify it. By the way I searched in the kernel file "esp4.c" but
> can't seem to find what I want.

Check xfrm*.c files, also net/xfrm directory.

-- 
Aidas Kasparas
IT administrator
GM Consult Group, UAB