If you want to run an 802.11 mesh without any special hardware, but instead use whatever laptop, raspberry pi or any other computer with wifi support, there's my mesh project: guerrilla-radio

https://gitlab.com/adam949/guerrilla-radio

Right now I only support a layer 2 bridge (which inheriently supports IPv6), but I started working on automating a setup that uses NAT (IPv4, obviously).

As long as MTUs are set properly, it works fine when setting things up manually. It's just the automation that needs work.