Wireguard Unbound Helper Scripts

host-add-static-route
Adds a static route to a host that may be on the other side of a
Wireguard tunnel. If a static route is not created, Wireguard may
attempt to connect to the host running Wireguard over the Wireguard
tunnel itself instead of across the Internet. Adding a static route
to the Wireguard host on tunnel creation prevents this situation.

unbound-host-add-local
Adds a local-data section to Unbound for the Wireguard host just in
case Unbound is connecting to a DNS server for a domain that is on
the other side of the tunnel. e.g. wg.natrinicle.com should be
retrieved from external DNS servers while all other natrinicle.com
subdomains should come from 192.168.0.1 which is only available after
the tunnel is up.

host-add-static-route

@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+
+LOCAL_HOSTNAME=${1}
+
+for LOCAL_IP in $(unbound-host ${LOCAL_HOSTNAME} | grep -Po "(([0-9]+\.){3}[0-9]+|([0-9a-f]+::?)+:?[0-9a-f]+)"); do
+  ROUTE=$(ip route get ${LOCAL_IP} | grep -P "(from|via)" 2>/dev/null)
+  if [ -z "${ROUTE}" ]; then
+    echo "No route for ${LOCAL_IP}"
+    continue
+  fi
+
+  DEV=$(echo ${ROUTE} | grep -Po "(?<=dev\s)[^\s]+")
+  SRC=$(echo ${ROUTE} | grep -Po "(?<=src\s)[^\s]+")
+
+  if [ -z "${DEV}" ]; then
+    echo "No dev for ${LOCAL_IP}"
+    continue
+  fi
+  if [ -z "${SRC}" ]; then
+    echo "No src for ${LOCAL_IP}"
+    continue
+  fi
+
+  if echo ${LOCAL_IP} | grep -q ":"; then
+    # IPv6
+    FROM=$(echo ${ROUTE} | grep -Po "(?<=from\s)[^\s]+")
+    if [ -n "${FROM}" ]; then
+      echo "Adding ${LOCAL_IP} from ${FROM} dev ${DEV} src ${SRC} metric 100"
+      ip route add ${LOCAL_IP} from ${FROM} dev ${DEV} src ${SRC} metric 100
+    fi
+  else
+    # IPv4
+    VIA=$(echo ${ROUTE} | grep -Po "(?<=via\s)[^\s]+")
+    if [ -n "${VIA}" ]; then
+      echo "Adding ${LOCAL_IP} via ${VIA} dev ${DEV} src ${SRC} metric 100"
+      ip route add ${LOCAL_IP} via ${VIA} dev ${DEV} src ${SRC} metric 100
+    fi
+  fi
+done

unbound-host-add-local

@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+
+LOCAL_HOSTNAME=${1}
+
+unbound-control local_data_remove ${LOCAL_HOSTNAME} > /dev/null 2>&1
+
+for dns_lookup in $(unbound-host ${LOCAL_HOSTNAME} | grep -Po "(([0-9]+\.){3}[0-9]+|([0-9a-f]+::?)+:?[0-9a-f]+)"); do
+  if echo ${dns_lookup} | grep -q ":"; then
+    unbound-control local_data ${LOCAL_HOSTNAME} IN AAAA ${dns_lookup} > /dev/null 2>&1
+  else
+    unbound-control local_data ${LOCAL_HOSTNAME} IN A ${dns_lookup} > /dev/null 2>&1
+  fi
+done