schnippets/host-add-static-route

#!/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