Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934152Ab1FWSE4 (ORCPT ); Thu, 23 Jun 2011 14:04:56 -0400 Received: from mail.windriver.com ([147.11.1.11]:34802 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933453Ab1FWRhI (ORCPT ); Thu, 23 Jun 2011 13:37:08 -0400 From: Paul Gortmaker To: stable@kernel.org, linux-kernel@vger.kernel.org Cc: stable-review@kernel.org, Ian Campbell , Ian Campbell , "David S. Miller" , Paul Gortmaker Subject: [34-longterm 148/247] arp_notify: unconditionally send gratuitous ARP for NETDEV_NOTIFY_PEERS. Date: Thu, 23 Jun 2011 13:33:36 -0400 Message-Id: <1308850515-15242-89-git-send-email-paul.gortmaker@windriver.com> X-Mailer: git-send-email 1.7.4.4 In-Reply-To: <1308850515-15242-1-git-send-email-paul.gortmaker@windriver.com> References: <1308849690-14530-1-git-send-email-paul.gortmaker@windriver.com> <1308850515-15242-1-git-send-email-paul.gortmaker@windriver.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2844 Lines: 89 From: Ian Campbell ------------------- This is a commit scheduled for the next v2.6.34 longterm release. If you see a problem with using this for longterm, please comment. ------------------- commit d11327ad6695db8117c78d70611e71102ceec2ac upstream. NETDEV_NOTIFY_PEER is an explicit request by the driver to send a link notification while NETDEV_UP/NETDEV_CHANGEADDR generate link notifications as a sort of side effect. In the later cases the sysctl option is present because link notification events can have undesired effects e.g. if the link is flapping. I don't think this applies in the case of an explicit request from a driver. This patch makes NETDEV_NOTIFY_PEER unconditional, if preferred we could add a new sysctl for this case which defaults to on. This change causes Xen post-migration ARP notifications (which cause switches to relearn their MAC tables etc) to be sent by default. Signed-off-by: Ian Campbell Signed-off-by: David S. Miller Signed-off-by: Paul Gortmaker --- net/ipv4/devinet.c | 30 ++++++++++++++++++++---------- 1 files changed, 20 insertions(+), 10 deletions(-) diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index c12777f..e85d771 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -1029,6 +1029,21 @@ static inline bool inetdev_valid_mtu(unsigned mtu) return mtu >= 68; } +static void inetdev_send_gratuitous_arp(struct net_device *dev, + struct in_device *in_dev) + +{ + struct in_ifaddr *ifa = in_dev->ifa_list; + + if (!ifa) + return; + + arp_send(ARPOP_REQUEST, ETH_P_ARP, + ifa->ifa_address, dev, + ifa->ifa_address, NULL, + dev->dev_addr, NULL); +} + /* Called only under RTNL semaphore */ static int inetdev_event(struct notifier_block *this, unsigned long event, @@ -1081,18 +1096,13 @@ static int inetdev_event(struct notifier_block *this, unsigned long event, } ip_mc_up(in_dev); /* fall through */ - case NETDEV_NOTIFY_PEERS: case NETDEV_CHANGEADDR: + if (!IN_DEV_ARP_NOTIFY(in_dev)) + break; + /* fall through */ + case NETDEV_NOTIFY_PEERS: /* Send gratuitous ARP to notify of link change */ - if (IN_DEV_ARP_NOTIFY(in_dev)) { - struct in_ifaddr *ifa = in_dev->ifa_list; - - if (ifa) - arp_send(ARPOP_REQUEST, ETH_P_ARP, - ifa->ifa_address, dev, - ifa->ifa_address, NULL, - dev->dev_addr, NULL); - } + inetdev_send_gratuitous_arp(dev, in_dev); break; case NETDEV_DOWN: ip_mc_down(in_dev); -- 1.7.4.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/