Routing all traffic to particular IP address via wifi network interface on MacOS

route_wifi.sh

#!/bin/bash

# NOTE: wifi/ethernet network interface is: en1
net_interface=en1
mac_network_interface=ifconfig $net_interface ether | sed -nl 's/\w*ether \([^ ]*\).*/\1/p' | sed 's/:/./g'
wifi_router=netstat -nr | grep default | grep $net_interface | perl -nle '/(\d+\.\d+\.\d+\.\d+)/ && print $1'
wifi_address=$net_interface:$mac_network_interface
TOADDR=`ifconfig $net_interface inet | sed -nl 's/\w*inet \([^ ]*\).*/\1/p'`
TO=`echo -n ${TOADDR//[[:space:]]}`

echo "ADDING ROUTE TO $1 VIA $net_interface: $TO"
route -n add -host $1 $wifi_router -ifp $wifi_address -ifa $TO -static

echo ""
echo "ROUTE ADDED:"
route get $1