Re: [PATCH net-next 2/5] tcp: TFO: search for correct cookie and accept data

[Eric Dumazet]

On 12/14/2018 02:40 PM, Christoph Paasch wrote:
> This change allows to search for the right cookie and accepts old ones
> (announcing a new one if it has changed).
> 
> __tcp_fastopen_cookie_gen_with_ctx() allows to generate a cookie based
> on a given TFO-context. A later patch will cleanup the duplicate code.

How long is kept the secondary (old) context ?

I do not know exact crypto_cipher_encrypt_one() cost, but it looks like
your patch could double the cost of some TFO based attacks ?