feat: Monitoring client

monitor.sh

@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+
+interface="${MADD_INTERFACE:-"eth0"}"
+client_script="${MADD_CLIENT_SCRIPT:-"./client.sh"}"
+
+ip monitor address label dev "$interface" | while read event; do
+    if [[ $event == \[ADDR\]* ]]; then
+        ipv4=$(ip addr show dev "$interface" | grep -Po 'inet \K[\d.]+')
+        if [ -n "$ipv4" ]; then
+            export MADD_IP="$ipv4"
+            $client_script
+        fi
+    fi
+done