Class: RubyDNS::Server

Inherits:
Object
  • Object
show all
Defined in:
lib/rubydns/server.rb

Direct Known Subclasses

RuleBasedServer

Constant Summary collapse

DEFAULT_INTERFACES =

The default server interfaces

[[:udp, "0.0.0.0", 53], [:tcp, "0.0.0.0", 53]]

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options) ⇒ Server

Instantiate a server with a block

server = Server.new do match(/server.mydomain.com/, IN::A) do |transaction| transaction.respond!("1.2.3.4") end end



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# File 'lib/rubydns/server.rb', line 40

def initialize(options)
	@logger = options[:logger] || Logger.new($stderr)
end

Instance Attribute Details

#logger ⇒ Object

Returns the value of attribute logger.



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# File 'lib/rubydns/server.rb', line 44

def logger
  @logger
end

Instance Method Details

#defer {|fiber| ... } ⇒ Object

Process a block with the current fiber. To resume processing from the block, call fiber.resume. You shouldn't call fiber.resume until after the top level block has returned.

Yields:

  • (fiber) 


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# File 'lib/rubydns/server.rb', line 56

def defer(&block)
	fiber = Fiber.current
	
	yield(fiber)
	
	Fiber.yield
end

#fire(event_name) ⇒ Object

Fire the named event as part of running the server.



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# File 'lib/rubydns/server.rb', line 47

def fire(event_name)
end

#process(name, resource_class, transaction) ⇒ Object

Give a name and a record type, try to match a rule and use it for processing the given arguments.

Raises:

  • (NotImplementedError) 


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# File 'lib/rubydns/server.rb', line 51

def process(name, resource_class, transaction)
	raise NotImplementedError.new
end

#process_query(query, options = {}, &block) ⇒ Object

Process an incoming DNS message. Returns a serialized message to be sent back to the client.



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# File 'lib/rubydns/server.rb', line 65

def process_query(query, options = {}, &block)
	start_time = Time.now
	
	# Setup answer
	answer = Resolv::DNS::Message::new(query.id)
	answer.qr = 1                 # 0 = Query, 1 = Response
	answer.opcode = query.opcode  # Type of Query; copy from query
	answer.aa = 1                 # Is this an authoritative response: 0 = No, 1 = Yes
	answer.rd = query.rd          # Is Recursion Desired, copied from query
	answer.ra = 0                 # Does name server support recursion: 0 = No, 1 = Yes
	answer.rcode = 0              # Response code: 0 = No errors
	
	Fiber.new do
		transaction = nil
		
		begin
			query.question.each do |question, resource_class|
				@logger.debug {"[#{query.id}] Processing question #{question} #{resource_class}..."}
		
				transaction = Transaction.new(self, query, question, resource_class, answer, options)
				
				transaction.process
			end
		rescue
			@logger.error {"[#{query.id}] Exception thrown while processing #{transaction}!"}
			RubyDNS.log_exception(@logger, $!)
		
			answer.rcode = Resolv::DNS::RCode::ServFail
		end
		
		yield answer
		
		end_time = Time.now
		@logger.debug {"[#{query.id}] Time to process request: #{end_time - start_time}s"}
	end.resume
end

#run(options = {}) ⇒ Object

By default the server runs on port 53, both TCP and UDP, which is usually a priviledged port and requires root access to bind. You can change this by specifying options[:listen] which should contain an array of [protocol, interface address, port] specifications.

INTERFACES = [[:udp, "0.0.0.0", 5300]] RubyDNS::run_server(:listen => INTERFACES) do ... end

You can specify already connected sockets if need be:

socket = UDPSocket.new; socket.bind("0.0.0.0", 53) Process::Sys.setuid(server_uid) INTERFACES = [socket]



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# File 'lib/rubydns/server.rb', line 116

def run(options = {})
	@logger.info "Starting RubyDNS server (v#{RubyDNS::VERSION})..."

	interfaces = options[:listen] || DEFAULT_INTERFACES

	fire(:setup)

	# Setup server sockets
	interfaces.each do |spec|
		@logger.info "Listening on #{spec.join(':')}"
		if spec[0] == :udp
			EventMachine.open_datagram_socket(spec[1], spec[2], UDPHandler, self)
		elsif spec[0] == :tcp
			EventMachine.start_server(spec[1], spec[2], TCPHandler, self)
		end
	end

	fire(:start)
end