From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Lunn Subject: Re: [RFC] Stable interface index option Date: Wed, 2 Dec 2015 02:41:18 +0100 Message-ID: <20151202014118.GD29814@lunn.ch> References: <20151201153441.GA17843@oracle.com> <20151201155052.GA14984@principal.rfc2324.org> <1448985743.3387258.454809153.36540D70@webmail.messagingengine.com> <20151201.142749.1921315575696738796.davem@davemloft.net> <1449001579.3817695.455078657.261B9C10@webmail.messagingengine.com> <20151201224325.GD14984@principal.rfc2324.org> <1449014338.3866712.455236865.50F81F7F@webmail.messagingengine.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Maximilian Wilhelm , netdev@vger.kernel.org To: Hannes Frederic Sowa Return-path: Received: from vps0.lunn.ch ([178.209.37.122]:50953 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754905AbbLBBlW (ORCPT ); Tue, 1 Dec 2015 20:41:22 -0500 Content-Disposition: inline In-Reply-To: <1449014338.3866712.455236865.50F81F7F@webmail.messagingengine.com> Sender: netdev-owner@vger.kernel.org List-ID: > In general the ifindexes are designed to not be reused very fast. Some parts of multicast group management rely on this. You need to remove group memberships from a socket when an interface has disappeared, e.g. a VPN interface has gone away. You can pass the ifindex of the no longer existing interface when removing the group memberships. If that ifindex has been re-used, you are going to have interesting race conditions. Andrew