Class: ResolvFiber::DNS::Requester

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

Overview

:nodoc:

Direct Known Subclasses

ConnectedUDP, TCP, UnconnectedUDP

Defined Under Namespace

Classes: ConnectedUDP, MDNSOneShot, RequestError, Sender, TCP, UnconnectedUDP

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Requester

Returns a new instance of Requester.



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# File 'lib/resolv_fiber.rb', line 667

def initialize
  @senders = {}
  @socks = nil
end

Instance Method Details

#close ⇒ Object 



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# File 'lib/resolv_fiber.rb', line 733

def close
  socks = @socks
  @socks = nil
  socks&.each(&:close)
end

#request(sender, tout) ⇒ Object 



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# File 'lib/resolv_fiber.rb', line 672

def request(sender, tout)
  start = Process.clock_gettime(Process::CLOCK_MONOTONIC)
  timelimit = start + tout
  begin
    sender.send
  rescue Errno::EHOSTUNREACH, # multi-homed IPv6 may generate this
        Errno::ENETUNREACH
    raise ResolvTimeout
  end

  while true
    before_select = Process.clock_gettime(Process::CLOCK_MONOTONIC)
    timeout = timelimit - before_select
    if timeout <= 0
      raise ResolvTimeout
    end

    Fiber.yield @socks, timelimit
    # Here, when this fiber is resumed, at least one of @socks is ready or it timed out.

    # `wait_readable` cannot be used here because it uses FiberScheduler#io_wait internally.
    select_result = IO.select(@socks, nil, nil, 0)

    # Below is the original implementation of resolv gem.
    #
    # if @socks.size == 1
    #   select_result = @socks[0].wait_readable(timeout) ? [ @socks ] : nil
    # else
    #   select_result = IO.select(@socks, nil, nil, timeout)
    # end
    if !select_result
      after_select = Process.clock_gettime(Process::CLOCK_MONOTONIC)
      next if after_select < timelimit
      raise ResolvTimeout
    end
    begin
      reply, from = recv_reply(select_result[0])
    rescue Errno::ECONNREFUSED, # GNU/Linux, FreeBSD
          Errno::ECONNRESET # Windows
      # No name server running on the server?
      # Don't wait anymore.
      raise ResolvTimeout
    end
    begin
      msg = Message.decode(reply)
    rescue DecodeError
      next # broken DNS message ignored
    end
    if sender == sender_for(from, msg)
      break
    else
      # unexpected DNS message ignored
    end
  end
  return msg, sender.data
end

#sender_for(addr, msg) ⇒ Object 



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# File 'lib/resolv_fiber.rb', line 729

def sender_for(addr, msg)
  @senders[[addr,msg.id]]
end