UDP Trash Hack for WireGuard on AsusWRT Merlin

WG UDP hack on AsusWRT-Merlin.md

UDP Trash Hack for WireGuard on AsusWRT Merlin

Подготовка

Проверяем, что включен пункт меню Enable JFFS custom scripts and configs

Установка

• Кладём файл wgclient-start в /jffs/scripts/
• Делаем скрипт запускаемым

chmod +x /jffs/scripts/wgclient-start

• Подключаем WG клиента в настройках роутера. Если клиент уже подключен, то выполняем команду /jffs/scripts/wgclient-start <номер впн клиента> (Например /jffs/scripts/wgclient-start 1 если подключен клиент под номером 1)
• Done ✅

Проверен на роутерах:

• ASUS RT-AX88U PRO, Merlin 3004.388.8_2
• ASUS RT-AX68U, Merlin 3004.388.8_2
• ASUS RT-AX86U
• ASUS RT-AX56U, Merlin 3004.388.8_2

wgclient-start

#!/bin/sh

# 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"
sleep 3
# Log the start of the script
logger -t WireGuardClient -p user.notice "Starting junk-udp-hack script"
logger -t WireGuardClient -p user.notice "Processing WG interface - $interface"

# Retrieve the server and port
wg_endpoint=$(wg show "$interface" endpoints 2>/dev/null || echo "")
if [ -z "$wg_endpoint" ]; then
    logger -s -t WireGuardClient -p user.err "Unable to retrieve endpoint for interface $interface" >&2
    exit 1
fi

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

if [ -z "$wg_server" ] || [ -z "$wg_port" ]; then
    logger -s -t WireGuardClient -p user.err "Unable to extract server or port for interface $interface" >&2
    exit 1
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 WireGuardClient -p user.warn "Port $l_port is already in use. Generating new one"
    sleep 1
    l_port=$(generate_random_port)
done

logger -t WireGuardClient -p user.notice "Setting connection to WG server $wg_server:$wg_port from client's 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"

logger -t WireGuardClient -p user.notice "Done"