netdev - Re: [PATCH v2 net] l2tp: Allow duplicate session creation with UDP

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Message-ID: <20200204120912.GA20493@pc-61.home>
Date:   Tue, 4 Feb 2020 13:09:12 +0100
From:   Guillaume Nault <gnault@...hat.com>
To:     Ridge Kennedy <ridge.kennedy@...iedtelesis.co.nz>
Cc:     netdev@...r.kernel.org, tparkin@...alix.com, jchapman@...alix.com
Subject: Re: [PATCH v2 net] l2tp: Allow duplicate session creation with UDP

On Tue, Feb 04, 2020 at 12:24:00PM +1300, Ridge Kennedy wrote:
> In the past it was possible to create multiple L2TPv3 sessions with the
> same session id as long as the sessions belonged to different tunnels.
> The resulting sessions had issues when used with IP encapsulated tunnels,
> but worked fine with UDP encapsulated ones. Some applications began to
> rely on this behaviour to avoid having to negotiate unique session ids.
> 
> Some time ago a change was made to require session ids to be unique across
> all tunnels, breaking the applications making use of this "feature".
> 
> This change relaxes the duplicate session id check to allow duplicates
> if both of the colliding sessions belong to UDP encapsulated tunnels.
> 
Thanks Ridge.

Even though it's already applied,
Reviewed-by: Guillaume Nault <gnault@...hat.com>
Tested-by: Guillaume Nault <gnault@...hat.com>