Openwrt

batman
https://openwrt.org/docs/guide-user/network/wifi/mesh/batman https://en.wikipedia.org/wiki/B.A.T.M.A.N.

https://github.com/open-mesh-mirror/batman-adv and https://www.open-mesh.org/projects/open-mesh/wiki, https://www.open-mesh.org/projects/batman-adv/wiki Batman advanced is a new approach to wireless networking which does no longer operate on the IP basis. Unlike the batman daemon, which exchanges information using UDP packets and sets routing tables, batman-advanced operates on ISO/OSI Layer 2 only and uses and routes (or better: bridges) Ethernet Frames. It emulates a virtual network switch of all nodes participating. Therefore all nodes appear to be link local, thus all higher operating protocols won't be affected by any changes within the network. You can run almost any protocol above batman advanced, prominent examples are: IPv4, IPv6, DHCP, IPX.

Batman advanced was implemented as a Linux kernel driver to reduce the overhead to a minimum. It does not depend on any (other) network driver, and can be used on wifi as well as ethernet lan, vpn, etc ... (anything with ethernet-style layer 2).

802.11s
https://github.com/o11s/open80211s

https://open80211s.org/

https://wireless.wiki.kernel.org/en/developers/Documentation/ieee80211/802.11s

https://openwrt.org/docs/guide-user/network/wifi/mesh/80211s

https://openwrt.org/docs/guide-user/network/wifi/mesh/mesh11sd

other
DD-WRT: A Linux-based firmware that provides a web-based GUI and extensive feature set, including support for virtual private networks (VPNs), advanced QoS, and hotspot functionality.

Tomato: A firmware that provides a simple and user-friendly web interface and advanced features such as bandwidth monitoring and management, advanced QoS, and VPN server and client support.

LEDE: An open-source firmware that was a fork of OpenWrt, but has since merged back into OpenWrt. It provides similar functionality to OpenWrt, but with a focus on stability and reliability.

pfSense: A firewall and router software based on FreeBSD that provides advanced features such as traffic shaping, load balancing, and VPN support.

VyOS: An open-source network operating system that can be installed on a variety of hardware platforms, and provides routing, firewall, VPN, and other network services.