Class: Async::DNS::DatagramHandler

Inherits:
GenericHandler show all
Defined in:
lib/async/dns/handler.rb

Overview

Handle incoming UDP requests, which are single data packets, and pass them on to the given server.

Instance Attribute Summary

Attributes inherited from GenericHandler

#The server that will process incoming queries., #server, #socket

Instance Method Summary collapse

Methods inherited from GenericHandler

#The socket to read/write data from/to.=, #error_response, #initialize, #process_query

Constructor Details

This class inherits a constructor from Async::DNS::GenericHandler

Instance Method Details

#respond(socket, input_data, remote_address) ⇒ Object

Respond to an incoming query.



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# File 'lib/async/dns/handler.rb', line 92

def respond(socket, input_data, remote_address)
  response = process_query(input_data, remote_address: remote_address)
  
  output_data = response.encode
  
  Console.debug "Writing #{output_data.bytesize} bytes response to client via UDP...", response_id: response.id
  
  if output_data.bytesize > UDP_REASONABLE_SIZE
    Console.warn "Response via UDP was larger than #{UDP_REASONABLE_SIZE}!", response_id: response.id
    
    # Reencode data with truncation flag marked as true:
    truncation_error = Resolv::DNS::Message.new(response.id)
    truncation_error.tc = 1
    
    output_data = truncation_error.encode
  end
  
  socket.sendmsg(output_data, 0, remote_address)
rescue IOError => error
  Console.error(self, "UDP response failed!", error: error)
rescue EOFError => error
  Console.error(self, "UDP session ended prematurely!", error: error)
rescue Resolv::DNS::DecodeError => error
  Console.error(self, "Could not decode incoming UDP data!", error: error)
end

#run(wrapper = ::IO::Endpoint::Wrapper.default) ⇒ Object

Run the handler, processing incoming UDP requests.



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# File 'lib/async/dns/handler.rb', line 81

def run(wrapper = ::IO::Endpoint::Wrapper.default)
  while true
    input_data, remote_address = @socket.recvmsg(UDP_MAXIMUM_SIZE)
    
    wrapper.async do
      respond(@socket, input_data, remote_address)
    end
  end
end