Class: Async::DNS::Server

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

Overview

A DNS server which can be used to resolve queries.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(endpoint = self.class.default_endpoint, origin: ".") ⇒ Server

Instantiate a server with a block.

Parameters:

  • endpoints (Array<(Symbol, String, Integer)>) —

    The endpoints to listen on.

  • origin (String) (defaults to: ".") —

    The default origin to resolve domains within.

  • logger (Console::Logger) —

    The logger to use.



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# File 'lib/async/dns/server.rb', line 36

def initialize(endpoint = self.class.default_endpoint, origin: ".")
  @endpoint = endpoint
  @origin = origin
end

Instance Attribute Details

#origin ⇒ String

Records are relative to this origin.

Returns:



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# File 'lib/async/dns/server.rb', line 44

def origin
  @origin
end

Class Method Details

.default_endpoint(port = 53) ⇒ Object

The default endpoint to listen on.



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# File 'lib/async/dns/server.rb', line 24

def self.default_endpoint(port = 53)
  ::IO::Endpoint.composite(
    ::IO::Endpoint.udp("localhost", port),
    ::IO::Endpoint.tcp("localhost", port)
  )
end

Instance Method Details

#logger ⇒ Object

Deprecated.

Use Console instead.



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# File 'lib/async/dns/server.rb', line 47

def logger
  Console
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.

Parameters:

  • name (String) —

    The resource name.

  • resource_class (Class<Resolv::DNS::Resource>) —

    The requested resource class.

  • transaction (Transaction) —

    The transaction object.



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# File 'lib/async/dns/server.rb', line 56

def process(name, resource_class, transaction)
  transaction.fail!(:NXDomain)
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 61

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)
        
        Console.debug(query) {"Processing question #{question} #{resource_class}..."}
        
        transaction = Transaction.new(self, query, question, resource_class, response, **options)
        
        transaction.process
      rescue Resolv::DNS::OriginError => error
        # This is triggered if the question is not part of the specified @origin:
        Console.error(self, "Failed to process question #{question} #{resource_class}!", error: error)
      end
    end
  rescue StandardError => error
    Console.error(query) {error}
    
    response.rcode = Resolv::DNS::RCode::ServFail
  end
  
  end_time = Time.now
  Console.debug(query) {"Time to process request: #{end_time - start_time}s"}
  
  return response
end

#run ⇒ Object

Setup all specified interfaces and begin accepting incoming connections.



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# File 'lib/async/dns/server.rb', line 103

def run
  Console.info "Starting Async::DNS server (v#{Async::DNS::VERSION})..."
  
  Async do |task|
    wrapper = @endpoint.wrapper
    
    @endpoint.bind do |server|
      Console.info "<> Listening for connections on #{server.local_address.inspect}"
      case server.local_address.socktype
      when Socket::SOCK_DGRAM
        DatagramHandler.new(self, server).run(wrapper)
      when Socket::SOCK_STREAM
        StreamHandler.new(self, server).run(wrapper)
      else
        raise ArgumentError.new("Don't know how to handle #{server}")
      end
    end
  end
end