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=-2.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no 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 3FF46C433FE for ; Wed, 9 Dec 2020 22:55:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0A14123B98 for ; Wed, 9 Dec 2020 22:55:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388017AbgLIWzD (ORCPT ); Wed, 9 Dec 2020 17:55:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58078 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729617AbgLIWyq (ORCPT ); Wed, 9 Dec 2020 17:54:46 -0500 Received: from mail-pf1-x42a.google.com (mail-pf1-x42a.google.com [IPv6:2607:f8b0:4864:20::42a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8189FC0613CF; Wed, 9 Dec 2020 14:54:06 -0800 (PST) Received: by mail-pf1-x42a.google.com with SMTP id i3so2172875pfd.6; Wed, 09 Dec 2020 14:54:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=lanATv4oPPkDwFaB9qQIK45VqUMTlXl+oCa+92TkqwA=; b=a1LJT7CHqVkFmpPPq4vfKK2iHYDskt9d+GXuzzpCWibXJC1W/p0QZTjJR6YKYQR8Iz RzGqgrBd52sbdim6Bi9MPNMld+VVyXPFECoaK0mUOwvsB8tZTlaaNoJFMeOW8cQxTEet lI3pKj2aVudpw8X5z1WYy0+uKlJRUqJQsJy6gFgVJPNL4dSi+TmO1BuDaLsbP4oy5tw3 H5WtWrkk5M6zfPoLmutuxcfzxOm6iqz5McABNS85JISQj1//HO1QtV7/qyCObtYUhNUm b6uKHxTOtbtrue3mIGyVoYQxQjfmytvIoF1YMI7gbYFOPsi3LFgtdRscTtaBi5Kh7RSZ hwCg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=lanATv4oPPkDwFaB9qQIK45VqUMTlXl+oCa+92TkqwA=; b=Hy6GDMUmbsedu3mealvufDDx7I4yqDbbRjA+CMGvNc4CKQtmGTpR7z6hi5AKm+A7Cy kBo00NILCGs0U3+JimWgyW7a4ze53zphBNZLIZqaXZ5h6lO60vBHAwqNpjhH2rEJxjsG P0E/o49ESV4IvDmnKt3wrV5ncwYh6XdbhdPOExaKyztvYjUGDjDD5eD8jWYsD8WaZNsS NYyBvL0uMDAlBIETyrlLMFmsmiyR+nyX/c3utH9fCtSa+3SdhJK0av1dasMkI4FJcp2U JEjBEoZrnastAhcFlCxgaqEPWXeOyabn0WcNIXo3rGkFd6cCEXvNT//OD6CSSrmAZMMF AsJw== X-Gm-Message-State: AOAM5321NgRrHaSZ3SywHCEhMZjoBNtEQV/JmJH996zHTN2hjWfZPb2+ 3b52OcmBsWMqD608qOGtx1YJX0kGQwmVWx8gqcDM0O9F1NI= X-Google-Smtp-Source: ABdhPJxvNEYjMtHCvrrd3d8QPr0FLUevAYtzuvTgv50hYEuM9Qo2B88b7nImNE+CfOrKtKYIjFVUj6z+23ZHe4VJp34= X-Received: by 2002:a62:5b05:0:b029:197:fafb:50f3 with SMTP id p5-20020a625b050000b0290197fafb50f3mr4125745pfb.76.1607554446124; Wed, 09 Dec 2020 14:54:06 -0800 (PST) MIME-Version: 1.0 References: <20201209033346.83742-1-xie.he.0141@gmail.com> <801dc0320e484bf7a5048c0cddac12af@AcuMS.aculab.com> In-Reply-To: <801dc0320e484bf7a5048c0cddac12af@AcuMS.aculab.com> From: Xie He Date: Wed, 9 Dec 2020 14:53:55 -0800 Message-ID: Subject: Re: [PATCH net-next] net: x25: Remove unimplemented X.25-over-LLC code stubs To: David Laight Cc: "David S. Miller" , Jakub Kicinski , "linux-x25@vger.kernel.org" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Martin Schiller Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 9, 2020 at 1:21 PM David Laight wrote: > > I always wondered about running Class 2 transport directly over LLC2 > (rather than Class 4 over LLC1). > But the only LLC2 user was netbios - and microsoft's LLC2 was broken. > Not to mention the window probing needed to handle systems that > said they supported a window of (IIRC) 15 but would discard the > 5th back to back frame. To me, LLC1 and LLC2 are to Ethernet what UDP and TCP are to IP networks. I think we can use LLC1 and LLC2 wherever UDP and TCP can be used, as long as we are in the same LAN and are willing to use MAC addresses as the addresses. X.25 layer 3 certainly can also run over LLC2. Linux actually has support for LLC1 and LLC2. User space programs can transmit data directly over LLC1 and LLC2 using "AF_LLC" sockets.