Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932765Ab1CEBFs (ORCPT ); Fri, 4 Mar 2011 20:05:48 -0500 Received: from kroah.org ([198.145.64.141]:47745 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932695Ab1CEBFL (ORCPT ); Fri, 4 Mar 2011 20:05:11 -0500 X-Mailbox-Line: From gregkh@clark.kroah.org Fri Mar 4 17:03:53 2011 Message-Id: <20110305010353.482533027@clark.kroah.org> User-Agent: quilt/0.48-11.2 Date: Fri, 04 Mar 2011 17:03:11 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Ian Campbell , "David S. Miller" , Haiyang Zhang , Mike Surcouf , Hank Janssen Subject: [17/18] arp_notify: unconditionally send gratuitous ARP for NETDEV_NOTIFY_PEERS. In-Reply-To: <20110305010410.GA18668@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2757 Lines: 90 2.6.32-longterm review patch. If anyone has any objections, please let us know. ------------------ From: Ian Campbell 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 [reported to solve hyperv live migration problem - gkh] Cc: Haiyang Zhang Cc: Mike Surcouf Cc: Hank Janssen Signed-off-by: Greg Kroah-Hartman --- net/ipv4/devinet.c | 30 ++++++++++++++++++++---------- 1 file changed, 20 insertions(+), 10 deletions(-) --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -1025,6 +1025,21 @@ static inline bool inetdev_valid_mtu(uns 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, @@ -1076,18 +1091,13 @@ static int inetdev_event(struct notifier } 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); -- 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/