check-wifi

#!/bin/bash
#
# started by cron every five minutes
#
# check if the wifi connection is still alive
#
# if not than restart connection
#
# echo on
# set -x

# --- Configuration ---
PING_TARGET="192.168.1.1" # A reliable IP on the local network (e.g., router)
WIFI_INTERFACE="wlan0"
MAX_RETRIES=3
RETRY_DELAY=15 # Seconds to wait after bringing interface up

# --- Script ---
SCRIPT_NAME="${0##*/}"

# Detect if running in an interactive terminal.
# This allows us to suppress output for cron and prevent reboots during manual runs.
if [ -t 1 ]; then
    IS_INTERACTIVE=true
else
    IS_INTERACTIVE=false
fi

# check if there is Wifi
# does it have an address?
if ping -c 1 -W 1 "$PING_TARGET" &> /dev/null; then
        logger -t "$SCRIPT_NAME" "Connection to $PING_TARGET is up."
        if $IS_INTERACTIVE; then
            echo "Connection is up."
        fi
else
        logger -t "$SCRIPT_NAME" "Connection down! Attempting reconnection..."
        echo "$SCRIPT_NAME: Connection down! Attempting reconnection..."

        for ((i=1; i<=MAX_RETRIES; i++)); do
            logger -t "$SCRIPT_NAME" "Reconnection attempt $i of $MAX_RETRIES..."
            echo "Reconnection attempt $i of $MAX_RETRIES..."

            # Restart the interface
            ip link set "$WIFI_INTERFACE" down
            sleep 5
            ip link set "$WIFI_INTERFACE" up
            sleep "$RETRY_DELAY" # Wait for it to reconnect and get an IP

            if ping -c 1 -W 1 "$PING_TARGET" &> /dev/null; then
                logger -t "$SCRIPT_NAME" "Connection restored."
                echo "Connection restored."
                exit 0
            fi
        done

        logger -t "$SCRIPT_NAME" "All reconnection attempts failed. Rebooting."
        if $IS_INTERACTIVE; then
            echo "All reconnection attempts failed. Would reboot if not in an interactive session."
        else
            echo "All reconnection attempts failed. Rebooting."
            # This command requires root privileges.
            /sbin/reboot
        fi
fi