#!/usr/bin/lua

--[[
Alpine Wall
Copyright (C) 2012 Kaarle Ritvanen
Licensed under the terms of GPL2
]]--

require 'alt_getopt'
require 'lfs'
require 'signal'
require 'stringy'

short_opts = 'o:V'
long_opts = {['output-dir']='o', verify='V'}

function help()
   io.stderr:write([[
Alpine Wall usage

Translate policy files to firewall configuration files:
    awall translate [-o|--output <dir>] [-V|--verify]

    The --verify option makes awall verify the configuration using the
    test mode of iptables-restore before overwriting the old files.

    Specifying the output directory allows testing awall policies
    without overwriting the current iptables and ipset configuration
    files. By default, awall generates the configuration to
    /etc/iptables and /etc/ipset.d, which are read by the init
    scripts.

Run-time activation of new firewall configuration:
    awall activate

    This command genereates firewall configuration from the policy
    files and enables it. If the user confirms the new configuration
    by hitting RETURN within 10 seconds, the configuration is saved to
    the files. Otherwise, the old configuration is restored.

Enable/disable optional policies:
    awall {enable|disable} <policy>...

List optional policies:
    awall list

    The 'enabled' status means that the policy has been enabled by the
    user. The 'disabled' status means that the policy is not in
    use. The 'required' status means that the policy has not been
    enabled by the user but is in use because it is required by
    another policy which is in use.

]])
   os.exit()
end

params = {}

if stringy.endswith(arg[0], '/awall-cli') then
   basedir = string.sub(arg[0], 1, -11)
   params.i = {basedir..'/json'}
   params.I = {}

   short_opts = short_opts..'i:I:'
   long_opts['input-dir'] = 'i'
   long_opts['import-path'] = 'I'
end

if not arg[1] then help() end

if not stringy.startswith(arg[1], '-') then
   mode = arg[1]
   table.remove(arg, 1)
end

opts, opind = alt_getopt.get_opts(arg, short_opts, long_opts)
for switch, value in pairs(opts) do
   if switch == 'V' then verify = true
   elseif switch == 'o' then
      iptdir = value
      ipsfile = value..'/ipset'
   else table.insert(params[switch], value) end
end

if not mode then
   mode = arg[opind]
   opind = opind + 1
end


require 'awall.util'

if not awall.util.contains({'translate', 'activate', 'fallback',
			    'enable', 'disable', 'list'},
			   mode) then help() end


require 'awall'

policyset = awall.PolicySet.new(params.i, params.I)

if mode == 'list' then
   for name, status, desc in policyset:list() do
       print(name, status, desc)
   end
   os.exit()
end

if awall.util.contains({'disable', 'enable'}, mode) then
   if opind > #arg then help() end
   repeat
      policyset[mode](policyset, arg[opind])
      opind = opind + 1
   until opind > #arg
   os.exit()
end


require 'awall.iptables'
awall.loadmodules(basedir)

config = awall.Config.new(policyset)

if mode == 'translate' then
   if verify then config:test() end
   config:dump(iptdir, ipsfile)      
   
elseif mode == 'activate' then

   awall.iptables.backup()

   signal.signal('SIGCHLD',
		 function() if pid and lpc.wait(pid, 1) then os.exit(2) end end)
   for i, sig in ipairs({'INT', 'TERM'}) do
      signal.signal('SIG'..sig, function()
				   interrupted = true
				   io.stdin:close()
				end)
   end

   require 'lpc'
   pid, stdio, stdout = lpc.run(arg[0], 'fallback')
   stdio:close()
   stdout:close()
   
   config:activate()

   io.stderr:write('New firewall configuration activated\n')
   io.stderr:write('Press RETURN to commit changes permanently: ')
   interrupted = not io.read()

   signal.signal('SIGCHLD', 'default')
   signal.kill(pid, 'SIGTERM')
   lpc.wait(pid)

   if interrupted then
      io.stderr:write('\nActivation canceled, reverting to the old configuration\n')
      awall.iptables.revert()

   else config:dump() end


elseif mode == 'fallback' then

   for i, sig in ipairs({'HUP', 'PIPE'}) do
      signal.signal('SIG'..sig, function() end)
   end

   require 'lsleep'
   lsleep.sleep(10)

   io.stderr:write('\nTimeout, reverting to the old configuration\n')
   awall.iptables.revert()

else assert(false) end