From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Abeni Subject: [PATCH net-next v3 2/2] ipv6: remove from fib tree aged out RTF_CACHE dst Date: Thu, 19 Oct 2017 16:07:11 +0200 Message-ID: <6440bf87fe967880ff90c1eb732081769f81f4a0.1508421311.git.pabeni@redhat.com> References: Cc: "David S. Miller" , Wei Wang , Eric Dumazet , Hannes Frederic Sowa , Martin KaFai Lau To: netdev@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:37372 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753599AbdJSOIL (ORCPT ); Thu, 19 Oct 2017 10:08:11 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: The commit 2b760fcf5cfb ("ipv6: hook up exception table to store dst cache") partially reverted the commit 1e2ea8ad37be ("ipv6: set dst.obsolete when a cached route has expired"). As a result, RTF_CACHE dst referenced outside the fib tree will not be removed until the next sernum change; dst_check() does not fail on aged-out dst, and dst->__refcnt can't decrease: the aged out dst will stay valid for a potentially unlimited time after the timeout expiration. This change explicitly removes RTF_CACHE dst from the fib tree when aged out. The rt6_remove_exception() logic will then obsolete the dst and other entities will drop the related reference on next dst_check(). pMTU exceptions are not aged-out, and are removed from the exception table only when the - usually considerably longer - ip6_rt_mtu_expires timeout expires. v1 -> v2: - do not touch dst.obsolete in rt6_remove_exception(), not needed v2 -> v3: - take care of pMTU exceptions, too Fixes: 2b760fcf5cfb ("ipv6: hook up exception table to store dst cache") Signed-off-by: Paolo Abeni --- net/ipv6/route.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 5c27313803d2..87a15cbd0e8b 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -1575,7 +1575,13 @@ static void rt6_age_examine_exception(struct rt6_exception_bucket *bucket, { struct rt6_info *rt = rt6_ex->rt6i; - if (atomic_read(&rt->dst.__refcnt) == 1 && + /* we are pruning and obsoleting aged-out and non gateway exceptions + * even if others have still references to them, so that on next + * dst_check() such references can be dropped. + * EXPIRES exceptions - e.g. pmtu-generated ones are pruned when + * expired, independently from their aging, as per RFC 8201 section 4 + */ + if (!(rt->rt6i_flags & RTF_EXPIRES) && time_after_eq(now, rt->dst.lastuse + gc_args->timeout)) { RT6_TRACE("aging clone %p\n", rt); rt6_remove_exception(bucket, rt6_ex); @@ -1595,6 +1601,10 @@ static void rt6_age_examine_exception(struct rt6_exception_bucket *bucket, rt6_remove_exception(bucket, rt6_ex); return; } + } else if (__rt6_check_expired(rt)) { + RT6_TRACE("purging expired route %p\n", rt); + rt6_remove_exception(bucket, rt6_ex); + return; } gc_args->more++; } -- 2.13.6