Re: IGMP on IPv6

[Cong Wang <xiyou.wangcong@gmail.com>]

On Tue, Apr 25, 2017 at 9:16 AM, Murali Karicheri <m-karicheri2@ti.com> wrote:
> On 04/18/2017 06:37 PM, Cong Wang wrote:
>> Did you assign IPv4 and IPv6 addresses to the HSR master device?
>
> No. I just used IPv4. From the trace mld_ifc_timer_expire() -> mld_sendpack() -> ip6_output()
> do you know what is it trying to do? Is it some neighbor discovery message or something
> going over the lower interface instead of the hsr interface?
>

IPv6 is special here because it has link-local address configured
automatically for each device, so this mld_ifc_timer is armed
for link-local multicasts. See:


 464         /* Join interface-local all-node multicast group */
 465         ipv6_dev_mc_inc(dev, &in6addr_interfacelocal_allnodes);
 466
 467         /* Join all-node multicast group */
 468         ipv6_dev_mc_inc(dev, &in6addr_linklocal_allnodes);
 469
 470         /* Join all-router multicast group if forwarding is set */
 471         if (ndev->cnf.forwarding && (dev->flags & IFF_MULTICAST))
 472                 ipv6_dev_mc_inc(dev, &in6addr_linklocal_allrouters);