feat: push IPv6 endpoint with DHCP when self-hosted DNS resolver is i…

…n use (angristan#600)

Co-authored-by: randomshell <43271778+randomshell@users.noreply.github.com>
Co-authored-by: Stanislas <angristan@pm.me>

openvpn-install.sh

@@ -159,10 +159,17 @@ prefetch: yes' >>/etc/unbound/unbound.conf
 	qname-minimisation: yes
 	prefetch: yes' >/etc/unbound/unbound.conf
 		fi
+
+		# IPv6 DNS for all OS
+		if [[ "$IPV6_SUPPORT" == 'y' ]]; then
+			echo 'interface: fd42:42:42:42::1
+access-control: fd42:42:42:42::/112 allow' >> /etc/unbound/unbound.conf
+		fi
 
 		if [[ ! $OS =~ (fedora|centos|amzn) ]]; then
 			# DNS Rebinding fix
 			echo "private-address: 10.0.0.0/8
+private-address: fd42:42:42:42::/112
 private-address: 172.16.0.0/12
 private-address: 192.168.0.0/16
 private-address: 169.254.0.0/16
@@ -183,13 +190,18 @@ hide-version: yes
 use-caps-for-id: yes
 prefetch: yes
 private-address: 10.0.0.0/8
+private-address: fd42:42:42:42::/112
 private-address: 172.16.0.0/12
 private-address: 192.168.0.0/16
 private-address: 169.254.0.0/16
 private-address: fd00::/8
 private-address: fe80::/10
 private-address: 127.0.0.0/8
-private-address: ::ffff:0:0/96' >/etc/unbound/openvpn.conf
+private-address: ::ffff:0:0/96' > /etc/unbound/openvpn.conf
+		if [[ "$IPV6_SUPPORT" == 'y' ]]; then
+			echo 'interface: fd42:42:42:42::1
+access-control: fd42:42:42:42::/112 allow' >> /etc/unbound/openvpn.conf
+		fi
 	fi
 
 	systemctl enable unbound
@@ -784,8 +796,11 @@ ifconfig-pool-persist ipp.txt" >>/etc/openvpn/server.conf
 			fi
 		done
 		;;
-	2) # Self-hosted DNS resolver (Unbound)
-		echo 'push "dhcp-option DNS 10.8.0.1"' >>/etc/openvpn/server.conf
+		2) # Self-hosted DNS resolver (Unbound)
+			echo 'push "dhcp-option DNS 10.8.0.1"' >> /etc/openvpn/server.conf
+			if [[ "$IPV6_SUPPORT" == 'y' ]]; then
+				echo 'push "dhcp-option DNS fd42:42:42:42::1"' >> /etc/openvpn/server.conf
+			fi
 		;;
 	3) # Cloudflare
 		echo 'push "dhcp-option DNS 1.0.0.1"' >>/etc/openvpn/server.conf