icmp6_send / icmpv6_send is invoked for both rx and tx paths. In both
cases the dst->dev should be preferred for determining the L3 domain
if the dst has been set on the skb. Fallback to the skb->dev if it has
not. This covers the case reported here where icmp6_send is invoked on
Rx before the route lookup.
Fixes: 5d41ce29e ("net: icmp6_send should use dst dev to determine L3 domain") Reported-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>