netdev - [PATCH] Reorder ACK/RST checking in LISTEN state

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Date:	Wed, 13 Feb 2008 00:38:13 -0600
From:	Kris Katterjohn <katterjohn@...il.com>
To:	netdev@...r.kernel.org
Subject: [PATCH] Reorder ACK/RST checking in LISTEN state

Hey everyone,

[I'm not subscribed, so please CC me on any replies]

I've attached a patch that changes the order of the ACK and RST checking 
in the LISTEN state in tcp_rcv_state_process() in tcp_input.c

Before:  If an ACK/RST packet is received, then tcp_rcv_state_process() 
would return 1 because of the ACK.  Then (following the function calls 
in tcp_ipv4.c and tcp_minisocks.c), tcp_v4_send_reset() is called--but 
since there is a RST in the packet it just returns.  After this, the 
kfree_skb() is called.  The same goes in tcp_ipv6.c as well.

But if the order of the ACK and RST checking is reversed, __kfree_skb() 
is called in tcp_rcv_state_process() because of the RST and the function 
returns 0, which skips that other useless stuff.

This is the order specified on page 65 of RFC 793 anyway.

Signed-off-by: Kris Katterjohn <katterjohn@...il.com>

Thanks,
Kris Katterjohn

View attachment "ackrst.patch" of type "text/x-patch" (413 bytes)