From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ido Schimmel Subject: [PATCH net] ipv6: Revert "ipv6: Allow non-gateway ECMP for IPv6" Date: Wed, 2 May 2018 22:41:56 +0300 Message-ID: <20180502194156.9275-1-idosch@mellanox.com> Mime-Version: 1.0 Content-Type: text/plain Cc: davem@davemloft.net, dsahern@gmail.com, eric.dumazet@gmail.com, Thomas.Winter@alliedtelesis.co.nz, mlxsw@mellanox.com, Ido Schimmel To: netdev@vger.kernel.org Return-path: Received: from mail-eopbgr50057.outbound.protection.outlook.com ([40.107.5.57]:12384 "EHLO EUR03-VE1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751152AbeEBTnA (ORCPT ); Wed, 2 May 2018 15:43:00 -0400 Sender: netdev-owner@vger.kernel.org List-ID: This reverts commit edd7ceb78296 ("ipv6: Allow non-gateway ECMP for IPv6"). Eric reported a division by zero in rt6_multipath_rebalance() which is caused by above commit that considers identical local routes to be siblings. The division by zero happens because a nexthop weight is not set for local routes. Revert the commit as it does not fix a bug and has side effects. To reproduce: # ip -6 address add 2001:db8::1/64 dev dummy0 # ip -6 address add 2001:db8::1/64 dev dummy1 Fixes: edd7ceb78296 ("ipv6: Allow non-gateway ECMP for IPv6") Signed-off-by: Ido Schimmel Reported-by: Eric Dumazet --- include/net/ip6_route.h | 3 ++- net/ipv6/ip6_fib.c | 3 +++ 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h index abceb5864d99..08b132381984 100644 --- a/include/net/ip6_route.h +++ b/include/net/ip6_route.h @@ -68,7 +68,8 @@ static inline bool rt6_need_strict(const struct in6_addr *daddr) static inline bool rt6_qualify_for_ecmp(const struct rt6_info *rt) { - return (rt->rt6i_flags & (RTF_ADDRCONF | RTF_DYNAMIC)) == 0; + return (rt->rt6i_flags & (RTF_GATEWAY|RTF_ADDRCONF|RTF_DYNAMIC)) == + RTF_GATEWAY; } void ip6_route_input(struct sk_buff *skb); diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index 3c97c29d4401..deab2db6692e 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -934,6 +934,9 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt, * list. * Only static routes (which don't have flag * RTF_EXPIRES) are used for ECMPv6. + * + * To avoid long list, we only had siblings if the + * route have a gateway. */ if (rt_can_ecmp && rt6_qualify_for_ecmp(iter)) -- 2.14.3