Implementation and basic usage for the DNS protocol

1 files changed, 189 insertions, 0 deletions

diff --git a/lib/custodian/protocol-tests/dns.rb b/lib/custodian/protocol-tests/dns.rb
new file mode 100755
index 0000000..0adac2f
--- /dev/null
+++ b/lib/custodian/protocol-tests/dns.rb
@@ -0,0 +1,189 @@
+#!/usr/bin/ruby1.8
+
+
+require 'resolv-replace'
+
+
+#
+#  This is a protocol tester for DNS.
+#
+class DNSTest
+
+  #
+  # Data passed from the JSON hash.
+  #
+  attr_reader :test_data
+
+  #
+  # The error text we return on failure.
+  #
+  attr_reader :error
+
+
+
+  #
+  # Save the data away.
+  #
+  def initialize( data )
+    @test_data = data
+    @error     = nil
+
+    #
+    # Ensure we have a host to monitor
+    #
+    if ( @test_data["target_host"].nil? )
+      @error = "Missing host to test against."
+      raise ArgumentError, @error
+    end
+
+    #
+    #  Ensure we have test-specific keys.
+    #
+    if ( @test_data["resolve_name"].nil? )
+      @error = "Missing host to resolve."
+      raise ArgumentError, @error
+    end
+    if ( @test_data["resolve_type"].nil? )
+      @error = "Missing type to resolve, for example A/MX/NS."
+      raise ArgumentError, @error
+    end
+    if ( @test_data["resolve_expected"].nil? )
+      @error = "Missing expected results to compare against.."
+      raise ArgumentError, @error
+    end
+  end
+
+
+  #
+  # Run the test.
+  #
+  #  Return "true" on success
+  #
+  #  Return "false" on failure.
+  #
+  # If the test fails the details should be retrieved from "error()".
+  #
+  def run_test
+
+    #
+    # Get the nameserver to resolve with
+    #
+    nameserver = @test_data["target_host"]
+
+    #
+    # Get the record type to lookup
+    #
+    record = @test_data["resolve_type"]
+
+    #
+    # Get the hostname to lookup
+    #
+    lookup = @test_data["resolve_name"]
+
+    #
+    # Get the expected results
+    #
+    expected = @test_data["resolve_expected"]
+
+    #
+    # Do the lookup
+    #
+    results = resolve_via( nameserver, record, lookup )
+
+    #
+    # Show the results if we found something.
+    #
+    if ( @test_data['verbose'] )
+      results.each do |res|
+        puts "Result: #{res}"
+      end
+    end
+
+    #
+    # OK we have an array of results.  If every one of the expected
+    # results is contained in those results returned then we're good.
+    #
+    expected.split( /;/ ).each do |required|
+      if ( ! results.include?( required ) )
+        @error = "The expected result #{required} was not found in the results: #{results.join(",")}"
+        return false
+      end
+    end
+
+    return true
+  end
+
+
+  #
+  # Resolve an IP
+  #
+  def resolve_via( server, ltype, name )
+    puts "Resolving #{name} [#{ltype}] via server #{server}"
+
+    results = Array.new()
+
+    Resolv::DNS.open(:nameserver=>[server]) do |dns|
+      case ltype
+      when /^A$/ then
+        dns.getresources(name, Resolv::DNS::Resource::IN::A).map{ |r| results.push r.address.to_s() }
+      when /^AAAA$/ then
+        dns.getresources(name, Resolv::DNS::Resource::IN::AAAA).map{ |r| results.push r.address.to_s() }
+
+      when /^NS$/ then
+        dns.getresources(name, Resolv::DNS::Resource::IN::MX).map{ |r| results.pushResolv.getaddresses(r.name.to_s()) }
+
+      when /^MX$/ then
+        dns.getresources(name, Resolv::DNS::Resource::IN::MX).map{ |r| results.push Resolv.getaddresses(r.exchange.to_s()) }
+      end
+    end
+
+    results.flatten!
+    return results
+  end
+
+
+  #
+  #  Return the error text for why this test failed.
+  #
+  def error
+    return @error
+  end
+
+
+
+
+end
+
+
+
+#
+# Sample test, for testing.
+#
+if __FILE__ == $0 then
+
+  #
+  #  Sample data.
+  #
+  test = {
+    "target_host"      => "a.ns.bytemark.co.uk",
+    "test_type"        => "dns",
+    "verbose"          => 1,
+    "test_alert"       => "DNS failure",
+    "resolve_name"     => "support.bytemark.co.uk",
+    "resolve_type"     => "MX",
+    "resolve_expected" => "89.16.184.148;89.16.184.149;89.16.184.150"
+  }
+
+
+  #
+  #  Run the test.
+  #
+  obj = DNSTest.new( test )
+  if ( obj.run_test )
+    puts "TEST OK"
+  else
+    puts "TEST FAILED"
+    puts obj.error()
+  end
+
+end