local bin = require "bin"
local nmap = require "nmap"
local stdnse = require "stdnse"

description = [[
Wakes a remote system up from sleep by sending a Wake-On-Lan packet.
]]

---
-- @usage
-- nmap --script broadcast-wake-on-lan --script-args broadcast-wake-on-lan.MAC='00:12:34:56:78:9A'
--
-- @output
-- Pre-scan script results:
-- | broadcast-wake-on-lan: 
-- |_  Sent WOL packet to: 10:9a:dd:a8:40:24
--
-- @args broadcast-wake-on-lan.MAC The MAC address of the remote system to wake up
-- @args broadcast-wake-on-lan.address The broadcast address to which the WoL packet is sent.
--

author = "Patrik Karlsson"
license = "Same as Nmap--See http://nmap.org/book/man-legal.html"
categories = {"broadcast", "safe"}

local MAC = stdnse.get_script_args("broadcast-wake-on-lan.MAC")
local address = stdnse.get_script_args("broadcast-wake-on-lan.address")

prerule = function()
	-- only run if we are ipv4 and have a MAC
	return (MAC ~= nil and nmap.address_family() == "inet")
end

-- Creates the WoL packet based on the remote MAC
-- @param mac string containing the MAC without delimiters
-- @return packet string containing the raw packet
local function createWOLPacket(mac)
	local packet = bin.pack("H", "FFFFFFFFFFFF")
	for i=1, 16 do
		packet = packet .. bin.pack("H", mac)
	end
	return packet
end


action = function()

	local MAC_hex
	if ( MAC:match("%x%x:%x%x:%x%x:%x%x:%x%x:%x%x") ) then
		MAC_hex = MAC:gsub(":", "")
	elseif( MAC:match("%x%x%-%x%x%-%x%x%-%x%x%-%x%x%-%x%x") ) then
		MAC_hex = MAC:gsub("-", "")
	else
		return "\n  ERROR: Failed to process MAC address"
	end
	
	local host = { ip = address or "255.255.255.255" }
	local port = { number = 9, protocol = "udp" }
	local socket = nmap.new_socket("udp")

	-- send two packets, just in case
	for i=1,2 do
		local packet = createWOLPacket(MAC_hex)
		local status, err = socket:sendto(host, port, packet)
		if ( not(status) ) then
			return "\n  ERROR: Failed to send packet"
		end
	end
	return stdnse.format_output(true, ("Sent WOL packet to: %s"):format(MAC))
end