Re: [PATCH 2/4] sctp: Add check for the TSN field of the SHUTDOWN chunk

[David Miller <davem@davemloft.net>]

From: Vlad Yasevich <vladislav.yasevich@hp.com>
Date: Tue, 21 Oct 2008 22:08:45 -0400

> If SHUTDOWN chunk is received Cumulative TSN Ack beyond the max tsn currently
> send, SHUTDOWN chunk be accepted and the association will be broken. New data
> is send, but after received SACK it will be drop because TSN in SACK is less
> than the Cumulative TSN, data will be retrans again and again even if correct
> SACK is received.
> 
> The packet sequence is like this:
> 
> Endpoint A                       Endpoint B       ULP
> (ESTABLISHED)                    (ESTABLISHED)
> 
>                <-----------      DATA (TSN=x-1)
> 
>                <-----------      DATA (TSN=x)
> 
>   SHUTDOWN     ----------->      (Now Cumulative TSN=x+1000)
>   (TSN=x+1000)
>                <-----------      DATA (TSN=x+1)
> 
>   SACK         ----------->      drop the SACK
>   (TSN=x+1)
>                <-----------      DATA (TSN=x+1)(retrans)
> 
> This patch fix this problem by terminating the association and respond to
> the sender with an ABORT.
> 
> Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
> Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>

Applied.