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Subject: RE: [RFC PATCH] network: return errors if we know tcp_connect
 failed
From: Eric Dumazet <eric.dumazet@gmail.com>
To: Eric Paris <eparis@redhat.com>
Cc: Hua Zhong <hzhong@gmail.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, davem@davemloft.net,
        kuznet@ms2.inr.ac.ru, pekkas@netcore.fi, jmorris@namei.org,
        yoshfuji@linux-ipv6.org, kaber@trash.net, paul.moore@hp.com
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Date: Fri, 12 Nov 2010 17:15:32 +0100
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Le vendredi 12 novembre 2010 à 11:08 -0500, Eric Paris a écrit :

> 2) What should the generic TCP code (tcp_connect()) do if the skb failed
> to send.  Should it return error codes back up the stack somehow or
> should they continue to be ignored?  Obviously continuing to just ignore
> information we have doesn't make me happy (otherwise I wouldn't have
> started scratching this itch).  But the point about ENOBUFS is well
> taken.  Maybe I should make tcp_connect(), or the caller to
> tcp_connect() more intelligent about specific error codes?
> 
> I'm looking for a path forward.  If SELinux is rejecting the SYN packets
> on connect() I want to pass that info to userspace rather than just
> hanging.  What's the best way to accomplish that?
> 

Eric, if you can differentiate a permanent reject, instead of a
temporary one (congestion, or rate limiting, or ENOBUF, or ...), then
yes, you could make tcp_connect() report to user the permanent error,
and ignore the temporary one.


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