From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C56628BF1 for ; Fri, 5 May 2023 16:59:36 +0000 (UTC) Received: from mail-pf1-x432.google.com (mail-pf1-x432.google.com [IPv6:2607:f8b0:4864:20::432]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 858E8191FE for ; Fri, 5 May 2023 09:59:35 -0700 (PDT) Received: by mail-pf1-x432.google.com with SMTP id d2e1a72fcca58-643a1656b79so716557b3a.3 for ; Fri, 05 May 2023 09:59:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20221208.gappssmtp.com; s=20221208; t=1683305975; x=1685897975; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=TAdX7eg2ryjY56yRTcHERosjHmSEk4LPOkzOv4IolK4=; b=bMx0T2PEF73qajo+15koX2YRbehw38va851NXwnFtJ+mx7MFBGachyQS2rCSICBrJD nKl3fDRQ6PZZDEISPPiQZSRzx4rCQzf/9u6ObKtD99AUSrcE4OU8Vj3SvaXrc1Zpi59B UV63xHiILreJPwcB+0X2kpT7RwwK9XRo7b5AkpqRuRy3XspTbIVhbzCLZgFvamWVn2fL H+BHrFUyixTE6Zdvitgjhunz5DILR+NuAYE7b4iXO+wUA/9SVOhZ406miG+13lhozflK 69B6dLb2TbWAICKHUngAXvDN+oZP9xOvotR9ROA2y7V/IGbBS1i7UNa/z2iTCPVGWiea 529A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683305975; x=1685897975; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=TAdX7eg2ryjY56yRTcHERosjHmSEk4LPOkzOv4IolK4=; b=ZILHQp4+VU9FZ16c0og4K/kbQIG05K+wegUwFcW+WdNlYhlk/XY7lYSwh0k4l20bvh R49FWbI9F7ucATehlUkW4rU1ISzlnBSVFCNMd+y/ImzX9bXDD6BjDLzxf/pM5e0qXlPl GRrVP/a7w+Lwdhlp4j/aURJuz5H+YPTF5FMmCoPtnCbfAWSBAqCEpKkU8Z31evzWCE3a tJxkcYavf+taN1ILByOwiFwiNg9RBPxvX3GwoBJ/u60gx/ZCxMZKQuKS40/aTmK+rAv8 8XAps3zmsEB5ba7Jb08To6kbnp0eEH00x9PL2YHfHpNSe3WgfzrnHlI0H29XniaiEGvU UTAg== X-Gm-Message-State: AC+VfDyMsQ2ZhhDOQNti71SZTDYpilkbXu6Za2dIjpp/AnFsvyrU+Lk7 cxP7r4CSxtfI42PRTjTM8TAahA== X-Google-Smtp-Source: ACHHUZ6FUzTYBCIMDTxJQxEa7xuKlQSBcvVlbcrDNPig9DMVntIYVrpgeqpY9QAuZ9kNhIc+Tjh/BQ== X-Received: by 2002:a05:6a20:4305:b0:f0:219e:f11c with SMTP id h5-20020a056a20430500b000f0219ef11cmr2887725pzk.31.1683305975026; Fri, 05 May 2023 09:59:35 -0700 (PDT) Received: from hermes.local (204-195-120-218.wavecable.com. [204.195.120.218]) by smtp.gmail.com with ESMTPSA id c25-20020aa78819000000b0064394d63458sm1871685pfo.78.2023.05.05.09.59.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 05 May 2023 09:59:34 -0700 (PDT) Date: Fri, 5 May 2023 09:59:32 -0700 From: Stephen Hemminger To: Chuck Lever Cc: netdev@vger.kernel.org, linux-rdma@vger.kernel.org, BMT@zurich.ibm.com, tom@talpey.com Subject: Re: [PATCH RFC 1/3] net/tun: Ensure tun devices have a MAC address Message-ID: <20230505095932.4025d469@hermes.local> In-Reply-To: <168330132769.5953.7109360341846745035.stgit@oracle-102.nfsv4bat.org> References: <168330051600.5953.11366152375575299483.stgit@oracle-102.nfsv4bat.org> <168330132769.5953.7109360341846745035.stgit@oracle-102.nfsv4bat.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On Fri, 05 May 2023 11:42:17 -0400 Chuck Lever wrote: > From: Chuck Lever > > A non-zero MAC address enables a network device to be assigned as > the underlying device for a virtual RDMA device. Without a non- > zero MAC address, cma_acquire_dev_by_src_ip() is unable to find the > underlying egress device that corresponds to a source IP address, > and rdma_resolve_address() fails. > > Signed-off-by: Chuck Lever > --- > drivers/net/tun.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index d4d0a41a905a..da85abfcd254 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -1384,7 +1384,7 @@ static void tun_net_initialize(struct net_device *dev) > > /* Point-to-Point TUN Device */ > dev->hard_header_len = 0; > - dev->addr_len = 0; > + dev->addr_len = ETH_ALEN; > dev->mtu = 1500; > > /* Zero header length */ This is a bad idea. TUN devices are L3 devices without any MAC address. This patch will change the semantics and break users. If you want an L2 address, you need to use TAP, not TUN device.