Commit 30ca22e4 authored May 02, 2018 by Ido Schimmel Committed by David S. Miller May 02, 2018

ipv6: Revert "ipv6: Allow non-gateway ECMP for IPv6"



This reverts commit edd7ceb7 ("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: edd7ceb7 ("ipv6: Allow non-gateway ECMP for IPv6")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Tested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 784813ae

include/net/ip6_route.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -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);

net/ipv6/ip6_fib.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -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))

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