This is a note to let you know that I've just added the patch titled ipv6: icmp6: Allow icmp messages to be looped back to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ipv6-icmp6-allow-icmp-messages-to-be-looped-back.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Wed Feb 28 16:13:29 CET 2018 From: Brendan McGrath <redmcg@xxxxxxxxxxxxxxxxxxx> Date: Wed, 13 Dec 2017 22:14:57 +1100 Subject: ipv6: icmp6: Allow icmp messages to be looped back From: Brendan McGrath <redmcg@xxxxxxxxxxxxxxxxxxx> [ Upstream commit 588753f1eb18978512b1c9b85fddb457d46f9033 ] One example of when an ICMPv6 packet is required to be looped back is when a host acts as both a Multicast Listener and a Multicast Router. A Multicast Router will listen on address ff02::16 for MLDv2 messages. Currently, MLDv2 messages originating from a Multicast Listener running on the same host as the Multicast Router are not being delivered to the Multicast Router. This is due to dst.input being assigned the default value of dst_discard. This results in the packet being looped back but discarded before being delivered to the Multicast Router. This patch sets dst.input to ip6_input to ensure a looped back packet is delivered to the Multicast Router. Signed-off-by: Brendan McGrath <redmcg@xxxxxxxxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv6/route.c | 1 + 1 file changed, 1 insertion(+) --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -1651,6 +1651,7 @@ struct dst_entry *icmp6_dst_alloc(struct } rt->dst.flags |= DST_HOST; + rt->dst.input = ip6_input; rt->dst.output = ip6_output; atomic_set(&rt->dst.__refcnt, 1); rt->rt6i_gateway = fl6->daddr; Patches currently in stable-queue which might be from redmcg@xxxxxxxxxxxxxxxxxxx are queue-4.9/ipv6-icmp6-allow-icmp-messages-to-be-looped-back.patch