#!/bin/sh

sleep 3
# Log the start of the script
logger -t WireGuardClientUp "Starting junk-udp-hack script after WireGuard client #$1 connection."

# Enable exit on error
set -e

# Function to generate a random number between 49152 and 65535
generate_random_port() {
    awk -v min=49152 -v max=65535 'BEGIN { srand(); print int(min + rand() * (max - min + 1)) }'
}

interface="wgc$1"

logger -t WireGuardClientUp "Processing WG interface - $interface"

# Retrieve the server and port
wg_endpoint=$(wg show "$interface" endpoints)
if [ -z "$wg_endpoint" ]; then
    logger -t WireGuardClientUp "Unable to retrieve endpoint for interface $interface" >&2
fi

wg_server=$(echo "$wg_endpoint" | awk '{print $2}' | cut -d':' -f1)
wg_port=$(echo "$wg_endpoint" | awk '{print $2}' | cut -d':' -f2)

if [ -z "$wg_server" ] || [ -z "$wg_port" ]; then
    logger -t WireGuardClientUp "Unable to extract server or port for interface $interface" >&2
fi

# Generate a random message
message=$(dd if=/dev/urandom bs=228 count=5 2>/dev/null | tr -dc 'A-Za-z0-9')

# Generate a new random port and ensure it's not in use
l_port=$(generate_random_port)
while netstat -an | grep -qE '(^|[^0-9])'"$l_port"'([^0-9]|$)'; do
    logger -t WireGuardClientUp "Port $l_port is already in use. Generating new one"
    l_port=$(generate_random_port)
done

logger -t WireGuardClientUp "WG server $wg_server:$wg_port Source port $l_port"

# Send the message using socat
echo "$message" | socat - UDP-SENDTO:"$wg_server:$wg_port",sourceport="$l_port"

# Update the WireGuard interface with the new listen port
wg set "$interface" listen-port "$l_port"