#!/usr/bin/lua

utl = require "luci.util"
sys = require "luci.sys"

require("luci.model.uci")
require("luci.sys.iptparser")

-- Init state session
local uci = luci.model.uci.cursor_state()
local ipt = luci.sys.iptparser.IptParser()
local net = sys.net
local fs = require "luci.fs"
local ip = require "luci.ip"

local debug = false

local has_ipv6 = fs.access("/proc/net/ipv6_route") and fs.access("/usr/sbin/ip6tables")

function lock()
	os.execute("lock /var/run/luci_splash.lock")
end

function unlock()
	os.execute("lock -u /var/run/luci_splash.lock")
end

function exec(cmd)
	local ret = sys.exec(cmd)
	if debug then
		print('+ ' .. cmd)
		if ret and ret ~= "" then
			print(ret)
		end
	end
end

function get_id(ip)
	local o3, o4 = ip:match("[0-9]+%.[0-9]+%.([0-9]+)%.([0-9]+)")
	if o3 and 04 then
		return string.format("%02X%s", tonumber(o3), "") .. string.format("%02X%s", tonumber(o4), "")
	else
		return false
	end
end

function get_device_for_ip(ipaddr)
	local dev
	uci:foreach("network", "interface", function(s)
		if s.ipaddr and s.netmask then
			local network = ip.IPv4(s.ipaddr, s.netmask)
			if network:contains(ip.IPv4(ipaddr)) then
				-- this should be rewritten to luci functions if possible
				dev = utl.trim(sys.exec(". /lib/functions/network.sh; network_get_device IFNAME '" ..  s['.name'] .. "'; echo $IFNAME"))
			end
		end
	end)
	return dev
end

function get_physdev(interface)
	local dev
	dev = utl.trim(sys.exec(". /lib/functions/network.sh; network_get_device IFNAME '" ..  interface .. "'; echo $IFNAME"))
	return dev
end



function get_filter_handle(parent, direction, device)
	local input = utl.split(sys.exec('/usr/sbin/tc filter show dev ' .. device .. ' parent ' .. parent) or {})
	local tbl = {}
	local handle
	for k, v in pairs(input) do
		handle = v:match('filter protocol ip pref %d+ u32 fh (%d*:%d*:%d*) order')
		if handle then
			local mac1, mac2, mac3, mac4, mac5, mac6
			if direction == 'src' then
				mac1, mac2, mac3, mac4 = input[k+1]:match('match ([%a%d][%a%d])([%a%d][%a%d])([%a%d][%a%d])([%a%d][%a%d])/ffffffff')
				mac5, mac6 = input[k+2]:match('match ([%a%d][%a%d])([%a%d][%a%d])0000/ffff0000')
			else
				mac1, mac2 = input[k+1]:match('match 0000([%a%d][%a%d])([%a%d][%a%d])/0000ffff')
				mac3, mac4, mac5, mac6 = input[k+2]:match('match ([%a%d][%a%d])([%a%d][%a%d])([%a%d][%a%d])([%a%d][%a%d])/ffffffff')
			end
			if mac1 and mac2 and mac3 and mac4 and mac5 and mac6 then
				mac = "%s:%s:%s:%s:%s:%s" % { mac1, mac2, mac3, mac4, mac5, mac6 }
				tbl[mac] = handle
			end
		end
	end
	if tbl[mac:lower()] then
		handle = tbl[mac:lower()]
	end
	return handle
end

function main(argv)
	local cmd = table.remove(argv, 1)
	local arg = argv[1]

	limit_up = (tonumber(uci:get("luci_splash", "general", "limit_up")) or 0) * 8
	limit_down = (tonumber(uci:get("luci_splash", "general", "limit_down")) or 0) * 8

	if ( cmd == "lease" or cmd == "add-rules" or cmd == "remove" or
	     cmd == "whitelist" or cmd == "blacklist" or cmd == "status" ) and #argv > 0
	then
		lock()

		local arp_cache      = net.arptable()
		local leased_macs    = get_known_macs("lease")
		local blacklist_macs = get_known_macs("blacklist")
		local whitelist_macs = get_known_macs("whitelist")

		for i, adr in ipairs(argv) do
			local mac = nil
			if adr:find(":") then
				mac = adr:lower()
			else
				for _, e in ipairs(arp_cache) do
					if e["IP address"] == adr then
						mac = e["HW address"]:lower()
						break
					end
				end
			end

			if mac and cmd == "add-rules" then
				if leased_macs[mac] then
					add_lease(mac, arp_cache, true)
				elseif blacklist_macs[mac] then
					add_blacklist_rule(mac)
				elseif whitelist_macs[mac] then
					add_whitelist_rule(mac)
				end
			elseif mac and cmd == "status" then
				print(leased_macs[mac] and "lease"
					or whitelist_macs[mac] and "whitelist"
					or blacklist_macs[mac] and "blacklist"
					or "new")
			elseif mac and ( cmd == "whitelist" or cmd == "blacklist" or cmd == "lease" ) then
				if cmd ~= "lease" and leased_macs[mac] then
					print("Removing %s from leases" % mac)
					remove_lease(mac)
					leased_macs[mac] = nil
				end

				if cmd ~= "whitelist" and whitelist_macs[mac] then
					print("Removing %s from whitelist" % mac)
					remove_whitelist(mac)
					whitelist_macs[mac] = nil					
				end

				if cmd ~= "blacklist" and blacklist_macs[mac] then
					print("Removing %s from blacklist" % mac)
					remove_blacklist(mac)
					blacklist_macs[mac] = nil
				end

				if cmd == "lease" and not leased_macs[mac] then
					print("Adding %s to leases" % mac)
					add_lease(mac)
					leased_macs[mac] = true
				elseif cmd == "whitelist" and not whitelist_macs[mac] then
					print("Adding %s to whitelist" % mac)
					add_whitelist(mac)
					whitelist_macs[mac] = true
				elseif cmd == "blacklist" and not blacklist_macs[mac] then
					print("Adding %s to blacklist" % mac)
					add_blacklist(mac)
					blacklist_macs[mac] = true
				else
					print("The mac %s is already %sed" %{ mac, cmd })
				end
			elseif mac and cmd == "remove" then
				if leased_macs[mac] then
					print("Removing %s from leases" % mac)
					remove_lease(mac)
					leased_macs[mac] = nil
				elseif whitelist_macs[mac] then
					print("Removing %s from whitelist" % mac)
					remove_whitelist(mac)
					whitelist_macs[mac] = nil					
				elseif blacklist_macs[mac] then
					print("Removing %s from blacklist" % mac)
					remove_blacklist(mac)
					blacklist_macs[mac] = nil
				else
					print("The mac %s is not known" % mac)
				end
			else
				print("Can not find mac for ip %s" % argv[i])
			end
		end

		unlock()
		os.exit(0)	
	elseif cmd == "sync" then
		sync()
		os.exit(0)
	elseif cmd == "list" then
		list()
		os.exit(0)
	else
		print("Usage:")
		print("\n  luci-splash list\n    List connected, black- and whitelisted clients")
		print("\n  luci-splash sync\n    Synchronize firewall rules and clear expired leases")
		print("\n  luci-splash lease <MAC-or-IP>\n    Create a lease for the given address")
		print("\n  luci-splash blacklist <MAC-or-IP>\n    Add given address to blacklist")
		print("\n  luci-splash whitelist <MAC-or-IP>\n    Add given address to whitelist")
		print("\n  luci-splash remove <MAC-or-IP>\n    Remove given address from the lease-, black- or whitelist")
		print("")

		os.exit(1)	
	end
end

-- Get a list of known mac addresses
function get_known_macs(list)
	local leased_macs = { }

	if not list or list == "lease" then
		uci:foreach("luci_splash_leases", "lease",
			function(s) leased_macs[s.mac:lower()] = true end)
	end

	if not list or list == "whitelist" then
		uci:foreach("luci_splash", "whitelist",
			function(s) leased_macs[s.mac:lower()] = true end)
	end

	if not list or list == "blacklist" then
		uci:foreach("luci_splash", "blacklist",
			function(s) leased_macs[s.mac:lower()] = true end)
	end

	return leased_macs
end


-- Helper to delete iptables rules
function ipt_delete_all(args, comp, off)
	off = off or { }
	for i, r in ipairs(ipt:find(args)) do
		if comp == nil or comp(r) then
			off[r.table] = off[r.table] or { }
			off[r.table][r.chain] = off[r.table][r.chain] or 0

			exec("iptables -t %q -D %q %d 2>/dev/null"
				%{ r.table, r.chain, r.index - off[r.table][r.chain] })

			off[r.table][r.chain] = off[r.table][r.chain] + 1
		end
	end
end

function ipt6_delete_all(args, comp, off)
	off = off or { }
	for i, r in ipairs(ipt:find(args)) do
		if comp == nil or comp(r) then
			off[r.table] = off[r.table] or { }
			off[r.table][r.chain] = off[r.table][r.chain] or 0

			exec("ip6tables -t %q -D %q %d 2>/dev/null"
				%{ r.table, r.chain, r.index - off[r.table][r.chain] })

			off[r.table][r.chain] = off[r.table][r.chain] + 1
		end
	end
end


-- Convert mac to uci-compatible section name
function convert_mac_to_secname(mac)
	return string.gsub(mac, ":", "")
end

-- Add a lease to state and invoke add_rule
function add_lease(mac, arp, no_uci)
	mac = mac:lower()

	-- Get current ip address
	local ipaddr
	for _, entry in ipairs(arp or net.arptable()) do
		if entry["HW address"]:lower() == mac then
			ipaddr = entry["IP address"]
			break
		end
	end

	-- Add lease if there is an ip addr
	if ipaddr then
		local device = get_device_for_ip(ipaddr)
		if not no_uci then
			uci:section("luci_splash_leases", "lease", convert_mac_to_secname(mac), {
				mac    = mac,
				ipaddr = ipaddr,
				device = device,
				limit_up = limit_up,
				limit_down = limit_down,
				start  = os.time()
			})
			uci:save("luci_splash_leases")
		end
		add_lease_rule(mac, ipaddr, device)
	else
		print("Found no active IP for %s, lease not added" % mac)
	end
end


-- Remove a lease from state and invoke remove_rule
function remove_lease(mac)
	mac = mac:lower()

	uci:delete_all("luci_splash_leases", "lease",
		function(s)
			if s.mac:lower() == mac then
				remove_lease_rule(mac, s.ipaddr, s.device, tonumber(s.limit_up), tonumber(s.limit_down))
				return true
			end
			return false
		end)
		
	uci:save("luci_splash_leases")
end


-- Add a whitelist entry
function add_whitelist(mac)
	uci:section("luci_splash", "whitelist", convert_mac_to_secname(mac), { mac = mac })
	uci:save("luci_splash")
	uci:commit("luci_splash")
	add_whitelist_rule(mac)
end


-- Add a blacklist entry
function add_blacklist(mac)
	uci:section("luci_splash", "blacklist", convert_mac_to_secname(mac), { mac = mac })
	uci:save("luci_splash")
	uci:commit("luci_splash")
	add_blacklist_rule(mac)
end


-- Remove a whitelist entry
function remove_whitelist(mac)
	mac = mac:lower()
	uci:delete_all("luci_splash", "whitelist",
		function(s) return not s.mac or s.mac:lower() == mac end)
	uci:save("luci_splash")
	uci:commit("luci_splash")
	remove_lease_rule(mac)
	remove_whitelist_tc(mac)
end

function remove_whitelist_tc(mac)
	if debug then
		print("Removing whitelist filters for " .. mac)
	end
        uci:foreach("luci_splash", "iface", function(s)
		local device = get_physdev(s['.name'])
		local handle = get_filter_handle('ffff:', 'src', device, mac)
		exec('tc filter del dev "%s" parent ffff: protocol ip prio 1 handle %s u32' % { device, handle })
		local handle = get_filter_handle('1:', 'dest', device, mac)
		exec('tc filter del dev "%s" parent 1:0 protocol ip prio 1 handle %s u32' % { device, handle })
        end)
end

-- Remove a blacklist entry
function remove_blacklist(mac)
	mac = mac:lower()
	uci:delete_all("luci_splash", "blacklist",
		function(s) return not s.mac or s.mac:lower() == mac end)
	uci:save("luci_splash")
	uci:commit("luci_splash")
	remove_lease_rule(mac)
end


-- Add an iptables rule
function add_lease_rule(mac, ipaddr, device)
	local id
	if ipaddr then
		id = get_id(ipaddr)
	end

	exec("iptables -t mangle -I luci_splash_mark_out -m mac --mac-source %q -j RETURN" % mac)

	if id and device then
		exec("iptables -t mangle -I luci_splash_mark_in -d %q -j MARK --set-mark 0x1%s -m comment --comment %s" % {ipaddr, id, mac:upper()})
	end

	if has_ipv6 then
		exec("ip6tables -t mangle -I luci_splash_mark_out -m mac --mac-source %q -j MARK --set-mark 79" % mac)
		-- not working yet, needs the ip6addr
		--exec("ip6tables -t mangle -I luci_splash_mark_in -d %q -j MARK --set-mark 80 -m comment --comment %s" % {ipaddr, mac:upper()})
	end


	if device and tonumber(limit_up) > 0 then
		exec('tc filter add dev "%s" parent ffff: protocol ip prio 2 u32 match ether src %s police rate %skbit mtu 6k burst 6k drop' % {device, mac, limit_up})
	end

	if id and device and tonumber(limit_down) > 0 then
		exec("tc class add dev %s parent 1: classid 1:0x%s htb rate %skbit" % { device, id, limit_down })
		exec("tc qdisc add dev %s parent 1:%s sfq perturb 10" % { device, id })
	end

	exec("iptables -t filter -I luci_splash_filter -m mac --mac-source %q -j RETURN" % mac)
	exec("iptables -t nat    -I luci_splash_leases -m mac --mac-source %q -j RETURN" % mac)
	if has_ipv6 then
		exec("ip6tables -t filter -I luci_splash_filter -m mac --mac-source %q -j RETURN" % mac)
	end
end


-- Remove lease, black- or whitelist rules
function remove_lease_rule(mac, ipaddr, device, limit_up, limit_down)
	local id
	if ipaddr then
		id = get_id(ipaddr)
	end

	ipt:resync()
	ipt_delete_all({table="mangle", chain="luci_splash_mark_in", options={"/*", mac:upper()}})
	ipt_delete_all({table="mangle", chain="luci_splash_mark_out", options={"MAC", mac:upper()}})
	ipt_delete_all({table="filter", chain="luci_splash_filter",   options={"MAC", mac:upper()}})
	ipt_delete_all({table="nat",    chain="luci_splash_leases",   options={"MAC", mac:upper()}})
	if has_ipv6 then
		ipt6_delete_all({table="mangle", chain="luci_splash_mark_out", options={"MAC", mac:upper()}})
		ipt6_delete_all({table="filter", chain="luci_splash_filter",   options={"MAC", mac:upper()}})
	end
	if device and tonumber(limit_up) > 0 then
		local handle = get_filter_handle('ffff:', 'src', device, mac)
		if handle then
			exec('tc filter del dev "%s" parent ffff: protocol ip prio 2 handle %s u32 police rate %skbit mtu 6k burst 6k drop' % {device, handle, limit_up})
		end
	end

	-- remove clients class
	if device and id then
		exec('tc class del dev "%s" classid 1:%s' % {device, id})
		exec('tc qdisc del dev "%s" parent 1:%s sfq perturb 10' % { device, id })
	end

end


-- Add whitelist rules
function add_whitelist_rule(mac)
	exec("iptables -t filter -I luci_splash_filter -m mac --mac-source %q -j RETURN" % mac)
	exec("iptables -t nat    -I luci_splash_leases -m mac --mac-source %q -j RETURN" % mac)
	if has_ipv6 then
		exec("ip6tables -t filter -I luci_splash_filter -m mac --mac-source %q -j RETURN" % mac)
	end
        uci:foreach("luci_splash", "iface", function(s)
		local device = get_physdev(s['.name'])
		exec('tc filter add dev "%s" parent ffff: protocol ip prio 1 u32 match ether src %s police pass' % { device, mac })
		exec('tc filter add dev "%s" parent 1:0 protocol ip prio 1 u32 match ether dst %s classid 1:1' % { device, mac })
        end)
end


-- Add blacklist rules
function add_blacklist_rule(mac)
	exec("iptables -t filter -I luci_splash_filter -m mac --mac-source %q -j DROP" % mac)
	if has_ipv6 then
		exec("ip6tables -t filter -I luci_splash_filter -m mac --mac-source %q -j DROP" % mac)
	end
end


-- Synchronise leases, remove abandoned rules
function sync()
	lock()

	local time = os.time()

	-- Current leases in state files
	local leases = uci:get_all("luci_splash_leases")
	
	-- Convert leasetime to seconds
	local leasetime = tonumber(uci:get("luci_splash", "general", "leasetime")) * 3600
	
	-- Clean state file
	uci:load("luci_splash_leases")
	uci:revert("luci_splash_leases")
	
	-- For all leases
	for k, v in pairs(leases) do
		if v[".type"] == "lease" then
			if os.difftime(time, tonumber(v.start)) > leasetime then
				-- Remove expired
				remove_lease_rule(v.mac, v.ipaddr, v.device, tonumber(v.limit_up), tonumber(v.limit_down))
			else
				-- Rewrite state
				uci:section("luci_splash_leases", "lease", convert_mac_to_secname(v.mac), {		
					mac    = v.mac,
					ipaddr = v.ipaddr,
					device = v.device,
					limit_up = limit_up,
					limit_down = limit_down,
					start  = v.start
				})
			end
		end
	end

	uci:save("luci_splash_leases")

	-- Get the mac addresses of current leases
	local macs = get_known_macs()

	ipt:resync()

	ipt_delete_all({table="filter", chain="luci_splash_filter", options={"MAC"}},
		function(r) return not macs[r.options[2]:lower()] end)
	ipt_delete_all({table="nat", chain="luci_splash_leases", options={"MAC"}},
		function(r) return not macs[r.options[2]:lower()] end)
	ipt_delete_all({table="mangle", chain="luci_splash_mark_out", options={"MAC", "MARK", "set"}},
		function(r) return not macs[r.options[2]:lower()] end)
	ipt_delete_all({table="mangle", chain="luci_splash_mark_in", options={"/*", "MARK", "set"}},
		function(r) return not macs[r.options[2]:lower()] end)


	if has_ipv6 then
		ipt6_delete_all({table="filter", chain="luci_splash_filter", options={"MAC"}},
			function(r) return not macs[r.options[2]:lower()] end)
		ipt6_delete_all({table="mangle", chain="luci_splash_mark_out", options={"MAC", "MARK", "set"}},
			function(r) return not macs[r.options[2]:lower()] end)
	end

	unlock()
end

-- Show client info
function list()
	-- Get current arp cache
	local arpcache = { }
	for _, entry in ipairs(net.arptable()) do
		arpcache[entry["HW address"]:lower()] = { entry["Device"]:lower(), entry["IP address"]:lower() }
	end

	-- Find traffic usage
	local function traffic(lease)
		local traffic_in  = 0
		local traffic_out = 0

		local rin  = ipt:find({table="mangle", chain="luci_splash_mark_in", destination=lease.ipaddr})
		local rout = ipt:find({table="mangle", chain="luci_splash_mark_out", options={"MAC", lease.mac:upper()}})

		if rin  and #rin  > 0 then traffic_in  = math.floor( rin[1].bytes / 1024) end
		if rout and #rout > 0 then traffic_out = math.floor(rout[1].bytes / 1024) end

		return traffic_in, traffic_out
	end

	-- Print listings
	local leases = uci:get_all("luci_splash_leases")

	print(string.format(
		"%-17s  %-15s  %-9s  %-4s  %-7s  %20s",
		"MAC", "IP", "State", "Dur.", "Intf.", "Traffic down/up"
	))

	-- Leases
	for _, s in pairs(leases) do
		if s[".type"] == "lease" and s.mac then
			local ti, to = traffic(s)
			local mac = s.mac:lower()
			local arp = arpcache[mac]
			print(string.format(
				"%-17s  %-15s  %-9s  %3dm  %-7s  %7dKB  %7dKB",
				mac, s.ipaddr, "leased",
				math.floor(( os.time() - tonumber(s.start) ) / 60),
				arp and arp[1] or "?", ti, to
			))
		end
	end

	-- Whitelist, Blacklist
	for _, s in utl.spairs(leases,
		function(a,b) return leases[a][".type"] > leases[b][".type"] end
	) do
		if (s[".type"] == "whitelist" or s[".type"] == "blacklist") and s.mac then
			local mac = s.mac:lower()
			local arp = arpcache[mac]
			print(string.format(
				"%-17s  %-15s  %-9s  %4s  %-7s  %9s  %9s",
				mac, arp and arp[2] or "?", s[".type"],
				"- ", arp and arp[1] or "?", "-", "-"
			))
		end
	end
end

main(arg)