netdev - Re: [PATCH net-next] tcp: remove redundant checks

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Message-Id: <20150604.010511.1149657919915294597.davem@davemloft.net>
Date:	Thu, 04 Jun 2015 01:05:11 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	eric.dumazet@...il.com
Cc:	netdev@...r.kernel.org
Subject: Re: [PATCH net-next] tcp: remove redundant checks

From: Eric Dumazet <eric.dumazet@...il.com>
Date: Wed, 03 Jun 2015 23:49:21 -0700

> From: Eric Dumazet  <edumazet@...gle.com>
> 
> tcp_v4_rcv() checks the following before calling tcp_v4_do_rcv():
> 
> if (th->doff < sizeof(struct tcphdr) / 4)
>     goto bad_packet;
> if (!pskb_may_pull(skb, th->doff * 4))
>     goto discard_it;
> 
> So following check in tcp_v4_do_rcv() is redundant
> and "goto csum_err;" is wrong anyway.
> 
> if (skb->len < tcp_hdrlen(skb) || ...)
> 	goto csum_err;
> 
> A second check can be removed after no_tcp_socket label for same reason.
> 
> Same tests can be removed in tcp_v6_do_rcv()
> 
> Note : short tcp frames are not properly accounted in tcpInErrs MIB,
> because pskb_may_pull() failure simply drops incoming skb, we might
> fix this in a separate patch.
> 
> Signed-off-by: Eric Dumazet  <edumazet@...gle.com>

Looks sane, applied, thanks Eric!
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