From patchwork Thu May 18 19:41:20 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ihar Hrachyshka X-Patchwork-Id: 764157 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3wTM5J36PJz9s4s for ; Fri, 19 May 2017 05:41:56 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754540AbdERTlu (ORCPT ); Thu, 18 May 2017 15:41:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45510 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932342AbdERTlk (ORCPT ); Thu, 18 May 2017 15:41:40 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id CB3FD80C26; Thu, 18 May 2017 19:41:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com CB3FD80C26 Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=ihrachys@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com CB3FD80C26 Received: from laptop.localdomain.com (ovpn-124-112.rdu2.redhat.com [10.10.124.112]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D88DB18104; Thu, 18 May 2017 19:41:38 +0000 (UTC) From: Ihar Hrachyshka To: davem@davemloft.net, ja@ssi.bg Cc: Ihar Hrachyshka , netdev@vger.kernel.org Subject: [PATCH v2 3/4] arp: postpone addr_type calculation to as late as possible Date: Thu, 18 May 2017 12:41:20 -0700 Message-Id: <774fefce840e229c1f062181ade2ea3b9a8c7eb7.1495136258.git.ihrachys@redhat.com> In-Reply-To: References: In-Reply-To: References: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Thu, 18 May 2017 19:41:39 +0000 (UTC) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The addr_type retrieval can be costly, so it's worth trying to avoid its calculation as much as possible. This patch makes it calculated only for gratuitous ARP packets. This is especially important since later we may want to move is_garp calculation outside of arp_accept block, at which point the costly operation will be executed for all setups. The patch is the result of a discussion in net-dev: http://marc.info/?l=linux-netdev&m=149506354216994 Suggested-by: Julian Anastasov Signed-off-by: Ihar Hrachyshka --- net/ipv4/arp.c | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c index ca6e1e6..c22103c 100644 --- a/net/ipv4/arp.c +++ b/net/ipv4/arp.c @@ -641,12 +641,12 @@ void arp_xmit(struct sk_buff *skb) } EXPORT_SYMBOL(arp_xmit); -static bool arp_is_garp(struct net_device *dev, int addr_type, - __be16 ar_op, +static bool arp_is_garp(struct net *net, struct net_device *dev, + int *addr_type, __be16 ar_op, __be32 sip, __be32 tip, unsigned char *sha, unsigned char *tha) { - bool is_garp = tip == sip && addr_type == RTN_UNICAST; + bool is_garp = tip == sip; /* Gratuitous ARP _replies_ also require target hwaddr to be * the same as source. @@ -659,6 +659,11 @@ static bool arp_is_garp(struct net_device *dev, int addr_type, tha && !memcmp(tha, sha, dev->addr_len); + if (is_garp) { + *addr_type = inet_addr_type_dev_table(net, dev, sip); + if (*addr_type != RTN_UNICAST) + is_garp = false; + } return is_garp; } @@ -859,18 +864,23 @@ static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb) n = __neigh_lookup(&arp_tbl, &sip, dev, 0); if (IN_DEV_ARP_ACCEPT(in_dev)) { - unsigned int addr_type = inet_addr_type_dev_table(net, dev, sip); + addr_type = -1; /* Unsolicited ARP is not accepted by default. It is possible, that this option should be enabled for some devices (strip is candidate) */ - is_garp = arp_is_garp(dev, addr_type, arp->ar_op, + is_garp = arp_is_garp(net, dev, &addr_type, arp->ar_op, sip, tip, sha, tha); if (!n && - ((arp->ar_op == htons(ARPOP_REPLY) && - addr_type == RTN_UNICAST) || is_garp)) + (is_garp || + (arp->ar_op == htons(ARPOP_REPLY) && + (addr_type == RTN_UNICAST || + (addr_type < 0 && + /* postpone calculation to as late as possible */ + inet_addr_type_dev_table(net, dev, sip) == + RTN_UNICAST))))) n = __neigh_lookup(&arp_tbl, &sip, dev, 1); }