*-mesh-vpn-wireguard-vxlan: should not rely on proper A and AAAA records of VPN-Gateway

[maurerle]

The current checkuplink script does currently only work if the Wireguard-Gateway has a functional A and AAAA DNS-Entry.
This should be the case in general, but is a weird limitation.

community-packages/ffmuc-mesh-vpn-wireguard-vxlan/files/lib/gluon/gluon-mesh-wireguard-vxlan/checkuplink

Lines 36 to 45 in 6b1de90

	if ip -6 route show table 1 | grep -q 'default via'
	then
	local ipv6
	ipv6="$(gluon-wan nslookup "$gateway" | grep 'Address:\? [0-9]' | grep -E -o '([a-f0-9:]+:+)+[a-f0-9]+')"
	echo "[$ipv6]$(echo "$peer_endpoint" | grep -E -oe ":[0-9]+$")"
	else
	local ipv4
	ipv4="$(gluon-wan nslookup "$gateway" | grep 'Address:\? [0-9]' | grep -oE "\b([0-9]{1,3}\.){3}[0-9]{1,3}\b")"
	echo "$ipv4$(echo "$peer_endpoint" | grep -E -oe ":[0-9]+$")"
	fi

This results in the following shortcomings:

1. if the client-wan has ipv6, but the gateway has no AAAA entry, then it will break
2. if the wireguard-gateway is already given as an ipv4 address and not as a DNS entry, the nslookup fails