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# Copyright, 2009, 2012, by Samuel G. D. Williams. <http://www.codeotaku.com>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
require_relative 'transport'
module RubyDNS
class GenericHandler
include Celluloid::IO
def initialize(server)
@server = server
@logger = @server.logger || Celluloid.logger
end
def error_response(query = nil, code = Resolv::DNS::RCode::ServFail)
# Encoding may fail, so we need to handle this particular case:
server_failure = Resolv::DNS::Message::new(query ? query.id : 0)
server_failure.qr = 1
server_failure.opcode = query ? query.opcode : 0
server_failure.aa = 1
server_failure.rd = 0
server_failure.ra = 0
server_failure.rcode = code
# We can't do anything at this point...
return server_failure
end
def process_query(data, options)
@logger.debug "<> Receiving incoming query (#{data.bytesize} bytes) to #{self.class.name}..."
query = nil
begin
query = RubyDNS::decode_message(data)
return @server.process_query(query, options)
rescue Celluloid::ResumableError
# Celluloid terminates tasks, we may be stuck in a task when the server is terminated. We don't want to reply to the client in this case, because the server is being terminated. It might be an option to return a server failure
raise
rescue StandardError => error
@logger.error "<> Error processing request: #{error.inspect}!"
RubyDNS::log_exception(@logger, error)
return error_response(query)
end
end
end
# Handling incoming UDP requests, which are single data packets, and pass them on to the given server.
class UDPSocketHandler < GenericHandler
include Celluloid::IO
def initialize(server, socket)
super(server)
@socket = socket
async.run
end
def run
loop { handle_connection }
end
def respond(input_data, remote_host, remote_port)
options = {peer: remote_host, port: remote_port, proto: :udp}
response = process_query(input_data, options)
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.send(output_data, 0, remote_host, remote_port)
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
def handle_connection
# @logger.debug "Waiting for incoming UDP packet #{@socket.inspect}..."
input_data, (_, remote_port, remote_host) = @socket.recvfrom(UDP_TRUNCATION_SIZE, 0)
async.respond(input_data, remote_host, remote_port)
rescue IOError => error
@logger.warn "<> UDP connection failed: #{error.inspect}!"
rescue EOFError => error
@logger.warn "<> UDP session ended prematurely!"
end
end
class UDPHandler < UDPSocketHandler
def initialize(server, host, port)
family = RubyDNS::address_family(host)
socket = UDPSocket.new(family)
socket.bind(host, port)
super(server, socket)
end
finalizer :finalize
def finalize
@socket.close if @socket
end
end
class TCPSocketHandler < GenericHandler
def initialize(server, socket)
super(server)
@socket = socket
async.run
end
def run
loop { async.handle_connection @socket.accept }
end
def handle_connection(socket)
_, remote_port, remote_host = socket.peeraddr
options = {peer: remote_host, port: remote_port, proto: :tcp}
input_data = StreamTransport.read_chunk(socket)
response = process_query(input_data, options)
length = StreamTransport.write_message(socket, response)
@logger.debug "<#{response.id}> Wrote #{length} bytes via TCP..."
rescue EOFError => error
@logger.warn "<> TCP session ended prematurely!"
rescue DecodeError
@logger.warn "<> Could not decode incoming TCP data!"
ensure
socket.close
end
end
class TCPHandler < TCPSocketHandler
def initialize(server, host, port)
socket = TCPServer.new(host, port)
super(server, socket)
end
finalizer :finalize
def finalize
@socket.close if @socket
end
end
end
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