From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heiner Kallweit Subject: Bug 71591 - Temporary address re-generated when it should not (public address about to expire) Date: Thu, 06 Mar 2014 17:29:12 +0100 Message-ID: <5318A258.1010100@web.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit To: netdev@vger.kernel.org Return-path: Received: from mout.web.de ([212.227.15.4]:60685 "EHLO mout.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751015AbaCFQ3R (ORCPT ); Thu, 6 Mar 2014 11:29:17 -0500 Received: from [192.168.178.101] ([84.153.198.61]) by smtp.web.de (mrweb001) with ESMTPSA (Nemesis) id 0Mdueb-1WY4XZ1xIT-00PhXV for ; Thu, 06 Mar 2014 17:29:16 +0100 Sender: netdev-owner@vger.kernel.org List-ID: Recently I faced the issue that a public address was about to expire and 3s before expiry a new temporary address was generated which instantly went into deprecated state. This didn't do any harm however it's wrong IMHO. Problem seems to be in function ipv6_create_tempaddr in addrconf.c. A new temporary address is generated if this condition is met: tmp_prefered_lft > regen_advance tmp_prefered_lft however is an offset from tstamp, not from now. This condition only checks that the new address is preferred until more than regen_advance from tstamp, but it should check that the new address is preferred until more than regen_advance from now. I submitted this issue to kernel bugzilla -> 71591 Hannes asked me to propose a patch, here it comes. Rgds, Heiner diff -uNr linux-3.10.32.vanilla/net/ipv6/addrconf.c linux-3.10.32.patched/net/ipv6/addrconf.c --- linux-3.10.32.vanilla/net/ipv6/addrconf.c 2014-02-22 14:41:54.000000000 -0600 +++ linux-3.10.32.patched/net/ipv6/addrconf.c 2014-03-06 17:07:12.953699438 -0600 @@ -1111,8 +1111,9 @@ * Lifetime is greater than REGEN_ADVANCE time units. In particular, * an implementation must not create a temporary address with a zero * Preferred Lifetime. + * Note that tmp_prefered_lft is relative to ifp->tstamp not now. */ - if (tmp_prefered_lft <= regen_advance) { + if (tmp_prefered_lft <= regen_advance + age) { in6_ifa_put(ifp); in6_dev_put(idev); ret = -1;