[Zrouter-src] ZRouter.org: push to ZRouter target/usr.bin/lua/luadns/mx.lua

[zrouter-src at zrouter.org]

details:   http://zrouter.org/hg/zrouter//rev/8284e9318ef7
changeset: 433:8284e9318ef7
user:      Aleksandr Rybalko <ray at ddteam.net>
date:      Thu Sep 20 00:39:22 2012 +0300
description:
Add simple test case for lua/dns.

diffstat:

 target/usr.bin/lua/luadns/mx.lua |  101 +++++++++++++++++++++++++++++++++++++++
 1 files changed, 101 insertions(+), 0 deletions(-)

diffs (105 lines):

diff -r cd9408568b77 -r 8284e9318ef7 target/usr.bin/lua/luadns/mx.lua
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/target/usr.bin/lua/luadns/mx.lua	Thu Sep 20 00:39:22 2012 +0300
@@ -0,0 +1,101 @@
+#!/usr/bin/env lua
+-- *************************************************************************
+--
+-- Copyright 2010 by Sean Conner.  All Rights Reserved.
+--
+-- This library is free software; you can redistribute it and/or modify it
+-- under the terms of the GNU Lesser General Public License as published by
+-- the Free Software Foundation; either version 3 of the License, or (at your
+-- option) any later version.
+-- 
+-- This library 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 Lesser General Public
+-- License for more details.
+-- 
+-- You should have received a copy of the GNU Lesser General Public License
+-- along with this library; if not, see <http://www.gnu.org/licenses/>.
+--
+-- **************************************************************************
+
+dns = require "dns"
+
+local SERVER = "8.8.8.8"
+
+-- **************************************************************
+
+local function query(host,type)
+  local e = dns.encode {
+  		id       = math.random(),
+  		query    = true,
+  		rd       = true,
+  		opcode   = 'query',
+  		question = {
+  			name  = host,
+  			type  = type,
+  			class = 'in'
+  		}
+  	}
+  	
+  local r,err = dns.query(SERVER,e)
+  
+  if r == nil then
+    print("error:",err)
+    return nil
+  end
+  
+  return dns.decode(r)
+end
+
+-- ****************************************************************
+
+local function query_a(host)
+  local a,err = query(host,'a')
+  
+  if a == nil then
+    print("error:",err)
+    return nil
+  end
+  
+  return a.answers[1]
+end
+
+-- ****************************************************************
+
+local function query_mx(host)
+  local mx,err = query(host,'mx')
+  
+  if mx == nil then
+    print("error:",err)
+    return nil
+  end
+  
+  table.sort(mx.answers,function(a,b) return a.preference < b.preference end)
+  
+  for i = 1 , #mx.answers do
+    mx.answers[i].ADDRESS = mx.additional[mx.answers[i].exchange]
+    if mx.answers[i].ADDRESS == nil then
+      mx.answers[i].ADDRESS = query_a(mx.answers[i].exchange)
+    end
+  end
+  
+  return mx.answers
+end
+
+-- **************************************************************
+
+if #arg == 0 then
+  io.stderr:write(string.format("usage: %s domain\n",arg[0]))
+  os.exit(1)
+end
+
+local results = query_mx(arg[1])
+
+for i = 1 , #results do
+  local mx,ip
+  
+  mx = results[i].exchange
+  ip = results[i].ADDRESS.address or "(none)"
+  
+  print(mx,ip)
+end