From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=DKIM_ADSP_ALL,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1883CC2D0B1 for ; Tue, 4 Feb 2020 10:27:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D723B21741 for ; Tue, 4 Feb 2020 10:27:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=katalix.com header.i=@katalix.com header.b="Abh812nV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726689AbgBDK1h (ORCPT ); Tue, 4 Feb 2020 05:27:37 -0500 Received: from mail.katalix.com ([3.9.82.81]:58122 "EHLO mail.katalix.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726506AbgBDK1g (ORCPT ); Tue, 4 Feb 2020 05:27:36 -0500 Received: from [IPv6:2a02:8010:6359:1:f9de:51c5:a310:b61b] (unknown [IPv6:2a02:8010:6359:1:f9de:51c5:a310:b61b]) (Authenticated sender: james) by mail.katalix.com (Postfix) with ESMTPSA id 898F08F822; Tue, 4 Feb 2020 10:27:35 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=katalix.com; s=mail; t=1580812055; bh=0o6QmOcMKw/rZxSgsdmiuJ1Nt+D2/4h6Zpq/EYE4t84=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=Abh812nVWzhTO++tSha3YyVufWvKNBXZmutDeY2PE3QaXNkk2esSKeA9EtkQphKGT GMsDzi6ngocH3TyFdiNZ+3uJcsMAk8N7Fte+xb4Equins7wbtzfT9jBnQvteuOY4ZU hZZKIKUYgcxIA59XIqNbfG+7pTCy7vkqu2fvxGVogkxoCK6/3aXLN/meI++B8MDIUP uGWeUfsvm2LPMPqU8cHAALCm4KrZpfzzEZijt23VDTL+y9ozEJklJlS0M8raCkyW+C fb0aQWRGmkEXcVgThfSWPcwX0v4NM0mNNRk3CPSBc8QWi5dFIX2lMChwwEhbvg9803 EWP5mSDXPAAgA== Subject: Re: [PATCH v2 net] l2tp: Allow duplicate session creation with UDP To: Ridge Kennedy , netdev@vger.kernel.org Cc: gnault@redhat.com, tparkin@katalix.com References: <20200203232400.28981-1-ridge.kennedy@alliedtelesis.co.nz> From: James Chapman Autocrypt: addr=jchapman@katalix.com; prefer-encrypt=mutual; keydata= xsBNBFDmvq0BCACizu6XvQjeWZ1Mnal/oG9AkCs5Rl3GULpnH0mLvPZhU7oKbgx5MHaFDKVJ rQTbNEchbLDN6e5+UD98qa4ebvNx1ZkoOoNxxiuMQGWaLojDKBc9x+baW1CPtX55ikq2LwGr 0glmtUF6Aolpw6GzDrzZEqH+Nb+L3hNTLBfVP+D1scd4R7w2Nw+BSQXPQYjnOEBDDq4fSWoI Cm2E18s3bOHDT9a4ZuB9xLS8ZuYGW6p2SMPFHQb09G82yidgxRIbKsJuOdRTIrQD/Z3mEuT/ 3iZsUFEcUN0T/YBN3a3i0P1uIad7XfdHy95oJTAMyrxnJlnAX3F7YGs80rnrKBLZ8rFfABEB AAHNJEphbWVzIENoYXBtYW4gPGpjaGFwbWFuQGthdGFsaXguY29tPsLAeAQTAQIAIgUCUOa+ rQIbIwYLCQgHAwIGFQgCCQoLBBYCAwECHgECF4AACgkQINzVgFp/OkBr2gf7BA4jmtvUOGOO JFsj1fDmbAzyE6Q79H6qnkgYm7QNEw7o+5r7EjaUwsh0w13lNtKNS8g7ZWkiBmSOguJueKph GCdyY/KOHZ7NoJw39dTGVZrvJmyLDn/CQN0saRSJZXWtV31ccjfpJGQEn9Gb0Xci0KjrlH1A cqxzjwTmBUr4S2EHIzCcini1KTtjbtsE+dKP4zqR/T52SXVoYvqMmJOhUhXh62C0mu8FoDM0 iFDEy4B0LcGAJt6zXy+YCqz7dOwhZBB4QX4F1N2BLF3Yd1pv8wBBZE7w70ds7rD7pnIaxXEK D6yCGrsZrdqAJfAgYL1lqkNffZ6uOSQPFOPod9UiZM7ATQRQ5r6tAQgAyROh3s0PyPx2L2Fb jC1mMi4cZSCpeX3zM9aM4aU8P16EDfzBgGv/Sme3JcrYSzIAJqxCvKpR+HoKhPk34HUR/AOk 16pP3lU0rt6lKel2spD1gpMuCWjAaFs+dPyUAw13py4Y5Ej2ww38iKujHyT586U6skk9xixK 1aHmGJx7IqqRXHgjb6ikUlx4PJdAUn2duqasQ8axjykIVK5xGwXnva/pnVprPSIKrydNmXUq BIDtFQ4Qz1PQVvK93KeCVQpxxisYNFRQ5TL6PtgVtK8uunABFdsRqlsw1Ob0+mD5fidITCIJ mYOL8K74RYU4LfhspS4JwT8nmKuJmJVZ5DjY2wARAQABwsBfBBgBAgAJBQJQ5r6tAhsMAAoJ ECDc1YBafzpA9CEH/jJ8Ye73Vgm38iMsxNYJ9Do9JvVJzq7TEduqWzAFew8Ft0F9tZAiY0J3 U2i4vlVWK8Kbnh+44VAKXYzaddLXAxOcZ8YYy+sVfeVoJs3lAH+SuRwt0EplHWvCK5AkUhUN jjIvsQoNBVUP3AcswIqNOrtSkbuUkevNMyPtd0GLS9HVOW0e+7nFce7Ow9ahKA3iGg5Re9rD UlDluVylCCNnUD8Wxgve4K+thRL9T7kxkr7aX7WJ7A4a8ky+r3Daf7OhGN9S/Z/GMSs0E+1P Qm7kZ2e0J6PSfzy9xDtoRXRNigtN2o8DHf/quwckT5T6Z6WiKEaIKdgaXZVhphENThl7lp8= Organization: Katalix Systems Ltd Message-ID: Date: Tue, 4 Feb 2020 10:27:35 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200203232400.28981-1-ridge.kennedy@alliedtelesis.co.nz> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Content-Language: en-US Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 03/02/2020 23:24, 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 tunnel= s, > 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 acr= oss > 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. > > Fixes: dbdbc73b4478 ("l2tp: fix duplicate session creation") > Signed-off-by: Ridge Kennedy Acked-by: James Chapman > --- > net/l2tp/l2tp_core.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c > index f82ea12bac37..425b95eb7e87 100644 > --- a/net/l2tp/l2tp_core.c > +++ b/net/l2tp/l2tp_core.c > @@ -322,8 +322,13 @@ int l2tp_session_register(struct l2tp_session *ses= sion, > =20 > spin_lock_bh(&pn->l2tp_session_hlist_lock); > =20 > + /* IP encap expects session IDs to be globally unique, while > + * UDP encap doesn't. > + */ > hlist_for_each_entry(session_walk, g_head, global_hlist) > - if (session_walk->session_id =3D=3D session->session_id) { > + if (session_walk->session_id =3D=3D session->session_id && > + (session_walk->tunnel->encap =3D=3D L2TP_ENCAPTYPE_IP || > + tunnel->encap =3D=3D L2TP_ENCAPTYPE_IP)) { > err =3D -EEXIST; > goto err_tlock_pnlock; > }