--
--  anylike
--
--  anylike is a ...
--  
--
--  Copyright (C) 2007-2008 Markus Grueneis <gimpf@anylike.org>
--                          Christian Pointner <equinox@anylike.org>
--
--  This file is part of anylike.
--
--  anylike is free software: you can redistribute it and/or modify
--  it under the terms of the GNU General Public License as published by
--  the Free Software Foundation, either version 3 of the License, or
--  any later version.
--
--  anylike is distributed in the hope that it will be useful,
--  but WITHOUT ANY WARRANTY; without even the implied warranty of
--  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
--  GNU General Public License for more details.
--
--  You should have received a copy of the GNU General Public License
--  along with anylike. If not, see <http://www.gnu.org/licenses/>.
--

socket = require("socket")

function echo_server() 
   local host, port = "localhost", 4500
   local ip, err = socket.dns.toip(host)
   if(ip == nil) then
      log.print("ERROR", "can't resolve " .. host .. ": " .. err)
      return -1
   end

   local udp, err = socket.udp()
   if(udp == nil) then
      log.print("ERROR", "can't create udp socket")
      return -1
   end
      
   local ret, err = udp:setsockname(ip, port)
   if(ret == nil) then
      log.print("ERROR", "setsockname(" .. ip .. "," .. port .. ") failed: " .. err)
      return -1
   end

   log.print("NOTICE", "echo server listening on " .. ip .. ":" .. port);
             
   while true do
      local dgrm, from_ip, from_port = udp:receivefrom()
      if(ret == nil) then
         log.print("ERROR", "receivefrom(" .. ip .. "," .. port .. ") failed: " .. from_ip)
         return -1
      end
      
      local ret, err = udp:sendto(dgrm, from_ip, from_port)
      if(ret == nil) then
         log.print("ERROR", "sendto(" .. ip .. "," .. port .. ") failed: " .. err)
         return -1
      end
      
      if(string.gsub(dgrm, "^(%w+)%s*%c$", "%1") ==  "quit") then
         return 0
      end
   end

   return 0
end