Thomas reported a regression with IPv6 and anycast using the following
reproducer:

    echo 1 >  /proc/sys/net/ipv6/conf/all/forwarding
    ip -6 a add fc12::1/16 dev lo
    sleep 2
    echo "pinging lo"
    ping6 -c 2 fc12::

The conversion of addrconf_f6i_alloc to use ip6_route_info_create missed
the use of fib6_is_reject which checks addresses added to the loopback
interface and sets the REJECT flag as needed. Update fib6_is_reject for
loopback checks to handle RTF_ANYCAST addresses.

Fixes: c7a1ce397ada ("ipv6: Change addrconf_f6i_alloc to use 
ip6_route_info_create")
Reported-by: thomas.gamb...@nexedi.com
Signed-off-by: David Ahern <dsah...@kernel.org>
---
 net/ipv6/route.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index ea0be7cf3d93..f3279810d765 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3405,7 +3405,7 @@ static bool fib6_is_reject(u32 flags, struct net_device 
*dev, int addr_type)
        if ((flags & RTF_REJECT) ||
            (dev && (dev->flags & IFF_LOOPBACK) &&
             !(addr_type & IPV6_ADDR_LOOPBACK) &&
-            !(flags & RTF_LOCAL)))
+            !(flags & (RTF_ANYCAST | RTF_LOCAL))))
                return true;
 
        return false;
-- 
2.17.1

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