Re: [PATCH 1/1] ipv6: Add sockopt IPV6_MULTICAST_ALL analogue to IP_MULTICAST_ALL

[David Miller]

From: Andre Naujoks <nautsch2@xxxxxxxxx>
Date: Mon, 10 Sep 2018 10:27:15 +0200

> The socket option will be enabled by default to ensure current behaviour
> is not changed. This is the same for the IPv4 version.
> 
> A socket bound to in6addr_any and a specific port will receive all traffic
> on that port. Analogue to IP_MULTICAST_ALL, disable this behaviour, if
> one or more multicast groups were joined (using said socket) and only
> pass on multicast traffic from groups, which were explicitly joined via
> this socket.
> 
> Without this option disabled a socket (system even) joined to multiple
> multicast groups is very hard to get right. Filtering by destination
> address has to take place in user space to avoid receiving multicast
> traffic from other multicast groups, which might have traffic on the same
> port.
> 
> The extension of the IP_MULTICAST_ALL socketoption to just apply to ipv6,
> too, is not done to avoid changing the behaviour of current applications.
> 
> Signed-off-by: Andre Naujoks <nautsch2@xxxxxxxxx>
> Acked-By: YOSHIFUJI Hideaki <yoshfuji@xxxxxxxxxxxxxx>

Applied to net-next, thank you.