From patchwork Fri May 5 15:41:50 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Chuck Lever X-Patchwork-Id: 13232789 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 07104C77B75 for ; Fri, 5 May 2023 15:42:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232943AbjEEPmF (ORCPT ); Fri, 5 May 2023 11:42:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40814 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232460AbjEEPmE (ORCPT ); Fri, 5 May 2023 11:42:04 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 843FB11DA6 for ; Fri, 5 May 2023 08:42:03 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 2154063EFC for ; Fri, 5 May 2023 15:42:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F0BBC433EF; Fri, 5 May 2023 15:42:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1683301322; bh=NB80E6sDOFiSRHYILHBdaX6WhxtoaeKVAuWkNhd3wwY=; h=Subject:From:To:Cc:Date:From; b=SrtVLCEhwHM/elDANECgFAdlbN0N3IWeoQ/5k0VXflXofpnHeosjPV320rVdktYOH YFfB1qfxCIRbFX7dkULQf5HcEAl+LAsNbDlraeeDHv0ysW1Nu5Bw3Bhe2lNaeU/KH3 slTeJbX1FGzkPQV8Am1F4o0wtB8Wd7hartj9cX9kIE4Xi0vguS/ve1Pi4NQRgwFpJ/ UAQw8wBfXRwL462/ik+k/VG1g2EkmLDv/DXSyGYg6CcjM1DkDgM/hLWZ/uDeqdoqwc cziv3sD9+u5CdyIZkE+gHyCyMzTSwDqx0jGXa9o43ZjKH3Ongy0irCUhR9C8fseL0r j6ZlmnROupgEw== Subject: [PATCH RFC 0/3] siw on tunnel devices From: Chuck Lever To: netdev@vger.kernel.org, linux-rdma@vger.kernel.org Cc: BMT@zurich.ibm.com, tom@talpey.com Date: Fri, 05 May 2023 11:41:50 -0400 Message-ID: <168330051600.5953.11366152375575299483.stgit@oracle-102.nfsv4bat.org> User-Agent: StGit/1.5 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org Chalk this one up to yet another crazy idea. At NFS testing events, we'd like to test NFS/RDMA over the event's private network. We can do that with iWARP using siw from guests. If the guest itself is on the VPN, that means siw's slave device is a tun device. Such devices have no MAC address. That breaks the RDMA core's ability to find the correct egress device for siw when given a source IP address. We've worked around this in the past with various software hacks, but we'd rather see full support for this capability in stock kernels. A direct and perhaps naïve way to do that is to give loopback and tun devices their own artificial MAC addresses for this purpose. --- Chuck Lever (3): net/tun: Ensure tun devices have a MAC address net/lo: Ensure lo devices have a MAC address RDMA/siw: Require non-zero 6-byte MACs for soft iWARP drivers/infiniband/sw/siw/siw_main.c | 22 +++++++--------------- drivers/net/loopback.c | 2 ++ drivers/net/tun.c | 6 +++--- 3 files changed, 12 insertions(+), 18 deletions(-) -- Chuck Lever