-- (c) William Welch 2005
--
-- This software is provided 'as-is', without any express or implied 
-- warranty. In no event will the authors be held liable for any damages 
-- arising from the use of this software.
--
-- Permission is granted to anyone to use this software for any purpose, 
-- including commercial applications, and to alter it and redistribute it 
-- freely, subject to the following restrictions:
--
-- 1. The origin of this software must not be misrepresented; 
--    you must not claim that you wrote the original software. 
--    If you use this software in a product, an acknowledgment in 
--    the product documentation would be appreciated but is not required.
--
-- 2. Altered source versions must be plainly marked as such, and must 
--    not be misrepresented as being the original software.
--
-- 3. This notice may not be removed or altered from any source distribution.
--
-- This license is commonly known as the zlib/libpng License.
--
-- william welch 7 march 2005. See RFC 826 for details on ARP.
-- revised 18 march 2005

function arp_is_for_me return bit is
  var byte i

  -- make sure it is an arp request
  if ! MemComp16Ex ( PKT , 12 , 6 , 8 )  then
     return false
   end if

  if MemRdEx ( PKT , 21 ) != 1 then
    return false
  end if

  -- matching my ip address
  if MemCompEx ( PKT , 38 , MYIP , 0 , 4 ) == false then
    return false
  end if

  return true
end function

procedure arp_reply is
  var byte i, t

  MemCpyEx ( PKT ,  0 , PKT , 6 , 6)
  MemCpyEx ( PKT , 32 , PKT , 6 , 6)

  MemCpyEx ( PKT ,  6 , MYMAC , 0 , 6 )
  MemCpyEx ( PKT , 22 , MYMAC , 0 , 6 )

  MemWrEx ( PKT , 21 , 2 )

  MemCpyEx ( PKT , 38 , PKT , 28 , 4 )
  MemCpyEx ( PKT , 28 , MYIP , 0 , 4 )

  net_txpkt ( 0 , 42 )
end procedure