netdev - Re: [RFC] tcp: randomize TCP source ports

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Message-ID: <1383876294.9412.136.camel@edumazet-glaptop2.roam.corp.google.com>
Date:	Thu, 07 Nov 2013 18:04:54 -0800
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Rick Jones <rick.jones2@...com>
Cc:	David Miller <davem@...emloft.net>, netdev <netdev@...r.kernel.org>
Subject: Re: [RFC] tcp: randomize TCP source ports

On Thu, 2013-11-07 at 17:07 -0800, Rick Jones wrote:

> For perhaps most definitions of well deployed.  There is at least one 
> load balancer which, while it offers TCP Window Scaling, does not also 
> offer TCP Time Stamps...
> 
> By rights they should (must) be offering TCP Time Stamps, and they are, 
> I am told, "working on it."
> 
> Is all going to be "well" when it is the (non-Linux) remote system which 
> has the TIME_WAIT endpoint?

Hey, tell us why netperf does a bind(port=0, addr=ANY) and SO_REUSEADDR
tricks before connect()

It seems you do request randomization, but you do not want it for
applications written by innocent people...

Current implementation is lazy at best, as a single @hint variable is
shared for all cpus, all users, so at moderate load there is actually no
guarantee of sequential allocations.

RFC 6056 has an interesting list of alternatives




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