Class: Async::DNS::DatagramHandler

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

Overview

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

Instance Attribute Summary

Attributes inherited from GenericHandler

#server, #socket

Instance Method Summary collapse

Methods inherited from GenericHandler

#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 



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# File 'lib/async/dns/handler.rb', line 80

def respond(socket, input_data, remote_address)
  response = process_query(input_data, remote_address: remote_address)
  
  output_data = response.encode
  
  @logger.debug "<#{response.id}> Writing #{output_data.bytesize} bytes response to client via UDP..."
  
  if output_data.bytesize > UDP_TRUNCATION_SIZE
    @logger.warn "<#{response.id}>Response via UDP was larger than #{UDP_TRUNCATION_SIZE}!"
    
    # 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
  @logger.warn "<> UDP response failed: #{error.inspect}!"
rescue EOFError => error
  @logger.warn "<> UDP session ended prematurely: #{error.inspect}!"
rescue DecodeError
  @logger.warn "<> Could not decode incoming UDP data!"
end

#run(task: Async::Task.current) ⇒ Object 



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# File 'lib/async/dns/handler.rb', line 70

def run(task: Async::Task.current)
  while true
    input_data, remote_address = @socket.recvmsg(UDP_TRUNCATION_SIZE)
    
    task.async do
      respond(@socket, input_data, remote_address)
    end
  end
end