#!/bin/bash
# Raspberry Pi 5 WiFi Monitor Mode Setup Script
# Run this script with sudo on your Raspberry Pi

set -e

# Configuration
WIFI_INTERFACE="wlan0"  # Change if your interface is different
MONITOR_INTERFACE="mon0"  # Monitor mode interface name
CHANNEL="${1:-11}"  # Default to channel 11, or pass as argument: ./rpi_monitor_setup.sh 36

echo "=== Raspberry Pi 5 WiFi Monitor Mode Setup ==="
echo "Interface: $WIFI_INTERFACE"
echo "Monitor interface: $MONITOR_INTERFACE"
echo "Channel: $CHANNEL"
echo ""

# Check if running as root
if [ "$EUID" -ne 0 ]; then 
    echo "Please run as root (use sudo)"
    exit 1
fi

# Check if interface exists
if ! ip link show "$WIFI_INTERFACE" &>/dev/null; then
    echo "Error: Interface $WIFI_INTERFACE not found"
    echo "Available interfaces:"
    ip link show | grep -E "^[0-9]+:" | awk '{print $2}' | sed 's/://'
    exit 1
fi

# Check if monitor interface already exists
if ip link show "$MONITOR_INTERFACE" &>/dev/null; then
    echo "Monitor interface $MONITOR_INTERFACE already exists. Removing..."
    iw dev "$MONITOR_INTERFACE" del
fi

# Bring down the interface
echo "Bringing down $WIFI_INTERFACE..."
ip link set "$WIFI_INTERFACE" down

# Set monitor mode
echo "Setting $WIFI_INTERFACE to monitor mode..."
iw dev "$WIFI_INTERFACE" set type monitor

# Bring up the monitor interface
echo "Bringing up monitor interface..."
ip link set "$WIFI_INTERFACE" up

# Set channel
echo "Setting channel to $CHANNEL..."
iw dev "$WIFI_INTERFACE" set channel "$CHANNEL"

# Verify monitor mode
echo ""
echo "=== Verification ==="
iw dev "$WIFI_INTERFACE" info

echo ""
echo "=== Monitor mode is now active! ==="
echo "Interface: $WIFI_INTERFACE"
echo "Channel: $CHANNEL"
echo ""
echo "To capture packets, you can use:"
echo "  sudo tcpdump -i $WIFI_INTERFACE -n"
echo "  sudo tcpdump -i $WIFI_INTERFACE -w capture.pcap"
echo "  sudo wireshark -i $WIFI_INTERFACE"
echo ""
echo "To stop monitor mode and restore normal WiFi:"
echo "  sudo ip link set $WIFI_INTERFACE down"
echo "  sudo iw dev $WIFI_INTERFACE set type managed"
echo "  sudo ip link set $WIFI_INTERFACE up"
echo "  # Then reconnect to your network"