[ Upstream commit 20314092 ]

v2:
a) moved before multicast source address check
b) changed comment to netdev style

Cc: Erik Hugne <erik.hugne@ericsson.com>
Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>