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=-5.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 6A489C388F7 for ; Tue, 10 Nov 2020 14:22:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 03EA3206A1 for ; Tue, 10 Nov 2020 14:22:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=akamai.com header.i=@akamai.com header.b="GmCe38qw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732299AbgKJOWA (ORCPT ); Tue, 10 Nov 2020 09:22:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59462 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726721AbgKJOWA (ORCPT ); Tue, 10 Nov 2020 09:22:00 -0500 Received: from mx0b-00190b01.pphosted.com (mx0b-00190b01.pphosted.com [IPv6:2620:100:9005:57f::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1FD1EC0613CF for ; Tue, 10 Nov 2020 06:22:00 -0800 (PST) Received: from pps.filterd (m0122331.ppops.net [127.0.0.1]) by mx0b-00190b01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 0AAEF2su019922; Tue, 10 Nov 2020 14:21:55 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=akamai.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=jan2016.eng; bh=bzsr6I01mEwqPHMp7Kai1Ifb6tt8RMl5iMCYL3nRC1s=; b=GmCe38qwGQBIgK/Kp4cpY0xoYZesrub+V1cQ/z9kEwxmLqWODPqZ+J4O91F1lJg1wU+1 EoM3TVJV8q0U8w0Ruwszl/s6fhrr33UjiW4cIZgqoSwMYiMidFUwaKum/ZX9B2+Pv6Z/ HsLk1dLMSmMxWSfyLsO50jy47oMOHpk/vHws2HzwHqqTOsgkpP+gm9gP5h0xaV+Arn+R 9gAQMpgVjiqLEcOlzYRfltLi3IJ1PlfMOA0b8sap5bwnnp+mC8M+uw9/L2jEB3Xw+2KC 9gl/+Lp3TVz+VQ0gxSuQ7y7yg3dGPdJaoXqbD2hF1OhfdzS8KaXP3/etmVETBu4KfMcb 3g== Received: from prod-mail-ppoint6 (prod-mail-ppoint6.akamai.com [184.51.33.61] (may be forged)) by mx0b-00190b01.pphosted.com with ESMTP id 34nhb5dx68-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 10 Nov 2020 14:21:54 +0000 Received: from pps.filterd (prod-mail-ppoint6.akamai.com [127.0.0.1]) by prod-mail-ppoint6.akamai.com (8.16.0.42/8.16.0.42) with SMTP id 0AAEJegB001778; Tue, 10 Nov 2020 09:21:53 -0500 Received: from prod-mail-relay11.akamai.com ([172.27.118.250]) by prod-mail-ppoint6.akamai.com with ESMTP id 34nqt2p9ej-1; Tue, 10 Nov 2020 09:21:53 -0500 Received: from [0.0.0.0] (stag-ssh-gw01.bos01.corp.akamai.com [172.27.113.23]) by prod-mail-relay11.akamai.com (Postfix) with ESMTP id 73DEC23CBB; Tue, 10 Nov 2020 14:21:53 +0000 (GMT) Subject: Re: [PATCH net V2] Exempt multicast addresses from five-second neighbor lifetime To: Jakub Kicinski Cc: netdev@vger.kernel.org, David Ahern , Nikolay Aleksandrov References: <20201109025052.23280-1-jdike@akamai.com> <20201109114733.0ee71b82@kicinski-fedora-PC1C0HJN.hsd1.ca.comcast.net> From: Jeff Dike Message-ID: Date: Tue, 10 Nov 2020 09:21:53 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201109114733.0ee71b82@kicinski-fedora-PC1C0HJN.hsd1.ca.comcast.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.312,18.0.737 definitions=2020-11-10_05:2020-11-10,2020-11-10 signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 bulkscore=0 suspectscore=0 adultscore=0 spamscore=0 malwarescore=0 mlxlogscore=846 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011100102 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.312,18.0.737 definitions=2020-11-10_05:2020-11-10,2020-11-10 signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 mlxlogscore=795 lowpriorityscore=0 priorityscore=1501 clxscore=1011 impostorscore=0 adultscore=0 malwarescore=0 phishscore=0 spamscore=0 mlxscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011100102 X-Agari-Authentication-Results: mx.akamai.com; spf=${SPFResult} (sender IP is 184.51.33.61) smtp.mailfrom=jdike@akamai.com smtp.helo=prod-mail-ppoint6 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi Jakub, On 11/9/20 2:47 PM, Jakub Kicinski wrote: > This makes sense because mcast L2 addr is calculated, not discovered, > and therefore can be recreated at a very low cost, correct? Yes. > Perhaps it would make sense to widen the API to any "computed" address > rather than implicitly depending on this behavior for mcast? I'm happy to do that, but I don't know of any other types of addresses which are computed and end up in the neighbors table. > I'm not an expert tho, maybe others disagree. > >> +static int arp_is_multicast(const void *pkey) >> +{ >> + return IN_MULTICAST(htonl(*((u32 *)pkey))); >> +} > > net/ipv4/arp.c:935:16: warning: cast from restricted __be32 > > s/u32/__be32/ > s/htonl/ntohl/ Thanks, I ran sparse, but must have missed that somehow. Jeff