[Bridge] [PATCH net] ipv6: Fix IPv6 packet loss in scenarios involving roaming + snooping switches

[David Miller]

From: Linus Lüssing <linus.luessing at c0d3.blue>
Date: Fri,  3 Feb 2017 08:11:03 +0100

> When for instance a mobile Linux device roams from one access point to
> another with both APs sharing the same broadcast domain and a
> multicast snooping switch in between:
> 
> 1)    (c) <~~~> (AP1) <--[SSW]--> (AP2)
> 
> 2)              (AP1) <--[SSW]--> (AP2) <~~~> (c)
> 
> Then currently IPv6 multicast packets will get lost for (c) until an
> MLD Querier sends its next query message. The packet loss occurs
> because upon roaming the Linux host so far stayed silent regarding
> MLD and the snooping switch will therefore be unaware of the
> multicast topology change for a while.
> 
> This patch fixes this by always resending MLD reports when an interface
> change happens, for instance from NO-CARRIER to CARRIER state.
> 
> Signed-off-by: Linus Lüssing <linus.luessing at c0d3.blue>

Looks good to me, applied, thanks.