Interest in adding multicast support to Wireguard?

[Derrick Lyndon Pallas]

I know this has come up a few times before, but if there was resolution, 
I couldn't find it.

I am trying to set up a hub-and-spoke network with many clients 
connected to a single concentrator. One application I need to support 
relies on mDNS. Because Wireguard does not allow overlapping ranges (for 
understandable reasons), this works on point-to-point links with two 
peers but not on hub-and-spoke or other multi-peer setups. This would be 
possible if every peer had its own hub interface, but that seems like an 
inelegant, error-prone workaround.

Some have suggested running vxlan or another encapsulation method on top 
of Wireguard, but that's not possible in this situation because I do not 
control the software running on the peers. Typically, they'll just be 
running the official Wireguard apps for MacOS or Windows.

Hacking Wireguard to understand the multicast range and to 
clone-and-forward this traffic to all peers does work. If there is wider 
interest in that specific feature, I'm happy to work what I have into 
something that could be upstreamed. Currently the range is global and 
hard-coded, but I could imagine wanting fine-grained control over which 
peers were interested in specific multicast addresses, e.g., for a 
user-space daemon managing IGMP subscriptions. However, before I spent 
time on any of the above, I wanted to gauge whether there was interest 
and whether that kind of feature might be accepted at all.

Thanks, ~Derrick