Class: Async::DNS::Server

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

Constant Summary collapse

DEFAULT_ENDPOINTS =

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(endpoints = DEFAULT_ENDPOINTS, origin: '.', logger: Async.logger) ⇒ 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/async/dns/server.rb', line 39

def initialize(endpoints = DEFAULT_ENDPOINTS, origin: '.', logger: Async.logger)
  @endpoints = endpoints
  @origin = origin
  @logger = logger
end

Instance Attribute Details

#logger ⇒ Object

Returns the value of attribute logger.



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# File 'lib/async/dns/server.rb', line 48

def logger
  @logger
end

#origin ⇒ Object

Records are relative to this origin:



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# File 'lib/async/dns/server.rb', line 46

def origin
  @origin
end

Instance Method Details

#fire(event_name) ⇒ Object

Fire the named event as part of running the server.



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# File 'lib/async/dns/server.rb', line 51

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/async/dns/server.rb', line 55

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/async/dns/server.rb', line 60

def process_query(query, options = {}, &block)
  start_time = Time.now
  
  # Setup response
  response = Resolv::DNS::Message::new(query.id)
  response.qr = 1                 # 0 = Query, 1 = Response
  response.opcode = query.opcode  # Type of Query; copy from query
  response.aa = 1                 # Is this an authoritative response: 0 = No, 1 = Yes
  response.rd = query.rd          # Is Recursion Desired, copied from query
  response.ra = 0                 # Does name server support recursion: 0 = No, 1 = Yes
  response.rcode = 0              # Response code: 0 = No errors
  
  transaction = nil
  
  begin
    query.question.each do |question, resource_class|
      begin
        question = question.without_origin(@origin)
        
        @logger.debug(query) {"Processing question #{question} #{resource_class}..."}
        
        transaction = Transaction.new(self, query, question, resource_class, response, options)
        
        transaction.process
      rescue Resolv::DNS::OriginError
        # This is triggered if the question is not part of the specified @origin:
        @logger.debug(query) {"Skipping question #{question} #{resource_class} because #{$!}"}
      end
    end
  rescue StandardError => error
    @logger.error(query) {error}
    
    response.rcode = Resolv::DNS::RCode::ServFail
  end
  
  end_time = Time.now
  @logger.debug(query) {"Time to process request: #{end_time - start_time}s"}
  
  return response
end

#run(*args) ⇒ Object

Setup all specified interfaces and begin accepting incoming connections.



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# File 'lib/async/dns/server.rb', line 102

def run(*args)
  @logger.info "Starting Async::DNS server (v#{Async::DNS::VERSION})..."
  
  Async::Reactor.run do |task|
    fire(:setup)
    
    Async::IO::Endpoint.each(@endpoints) do |endpoint|
      task.async do
        endpoint.bind do |socket|
          case socket.type
          when Socket::SOCK_DGRAM
            @logger.info "<> Listening for datagrams on #{socket.local_address.inspect}"
            DatagramHandler.new(self, socket).run
          when Socket::SOCK_STREAM
            @logger.info "<> Listening for connections on #{socket.local_address.inspect}"
            StreamHandler.new(self, socket).run
          else
            raise ArgumentError.new("Don't know how to handle #{address}")
          end
        end
      end
    end
    
    fire(:start)
  end
end