netdev - Re: [PATCH 1/1] tproxy: do not assign timewait sockets to skb->sk

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Message-ID: <20110217212717.GG8821@Chamillionaire.breakpoint.cc>
Date:	Thu, 17 Feb 2011 22:27:17 +0100
From:	Florian Westphal <fw@...len.de>
To:	Balazs Scheidler <bazsi@...abit.hu>
Cc:	Florian Westphal <fw@...len.de>, netfilter-devel@...r.kernel.org,
	netdev@...r.kernel.org, KOVACS Krisztian <hidden@...abit.hu>
Subject: Re: [PATCH 1/1] tproxy: do not assign timewait sockets to skb->sk

Balazs Scheidler <bazsi@...abit.hu> wrote:
> the destination port in the packet can be different in the two lookups. --on-port tproxy option.

Hrm...  The initial lookup uses the header ip addresses:
        sk = nf_tproxy_get_sock_v4(dev_net(skb->dev), iph->protocol,
                                   iph->saddr, iph->daddr,
                                   hp->source, hp->dest,
                                   skb->dev, NFT_LOOKUP_ESTABLISHED);

3 possible cases:
- no socket -- try to find listener. This case is not changed by my patch.
- sk is normal socket. set nfmark and skb->sk. Also not changed.
- sk is in TW state. This is not changed either:
	tproxy_handle_time_wait4() will check if this is a SYN. If it is, a new
	listener lookup is made, and TW socket is kicked out.

If the packet is not a SYN, then tproxy_handle_time_wait4() won't do anything.
Previously, the timewait sk would now be assigned to skb->sk, which my patch
prevents.  But I don't see where the '--on-port' port number is involved in the
TW socket lookup?

Thanks for reviwing the patch!
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