Class: Dnsruby::ResolverRuby
- Inherits:
-
Object
- Object
- Dnsruby::ResolverRuby
- Defined in:
- lib/dnsruby/resolver.rb
Overview
This class implements the I/O using pure Ruby, with no dependencies.
Support for EventMachine has been deprecated.
Instance Method Summary collapse
-
#close ⇒ Object
Close the Resolver.
-
#decrement_resolver_priority(res) ⇒ Object
TO BE CALLED IN A SYNCHRONIZED BLOCK.
-
#demote_resolver(res) ⇒ Object
TO BE CALLED IN A SYNCHRONIZED BLOCK.
-
#generate_timeouts ⇒ Object
:nodoc: all.
-
#handle_error_response(select_queue, query_id, error, response) ⇒ Object
:nodoc: all.
-
#handle_queue_event(queue, id) ⇒ Object
This method is called by the SelectThread (in the select thread) when the queue has a new item on it.
-
#handle_response(select_queue, query_id, response) ⇒ Object
:nodoc: all.
- #handle_validation_error(select_queue, query_id, error, response) ⇒ Object
-
#handle_validation_response(select_queue, query_id, response) ⇒ Object
:nodoc: all.
-
#increment_resolver_priority(res) ⇒ Object
TO BE CALLED IN A SYNCHRONIZED BLOCK.
-
#initialize(parent) ⇒ ResolverRuby
constructor
:nodoc: all.
-
#reset_attributes ⇒ Object
:nodoc: all.
- #send_async(msg, client_queue, client_query_id = nil) ⇒ Object
-
#send_result(client_queue, client_query_id, select_queue, msg, error) ⇒ Object
MUST BE CALLED IN A SYNCHRONIZED BLOCK! Sends the result to the client’s queue, and removes the queue observer from the select thread.
-
#send_result_and_stop_querying(client_queue, client_query_id, select_queue, msg, error) ⇒ Object
MUST BE CALLED IN A SYNCHRONIZED BLOCK! Send the result back to the client, and close the socket for that query by removing the query from the select thread.
-
#stop_querying(client_query_id) ⇒ Object
MUST BE CALLED IN A SYNCHRONIZED BLOCK! Stops send any more packets for a client-level query.
-
#tick ⇒ Object
This method is called twice a second from the select loop, in the select thread.
Constructor Details
#initialize(parent) ⇒ ResolverRuby
:nodoc: all
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# File 'lib/dnsruby/resolver.rb', line 806 def initialize(parent) reset_attributes @parent=parent end |
Instance Method Details
#close ⇒ Object
Close the Resolver. Unfinished queries are terminated with OtherResolvError.
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# File 'lib/dnsruby/resolver.rb', line 884 def close # @mutex.synchronize { @parent.single_res_mutex.synchronize { @query_list.each do |client_query_id, values| _msg, client_queue, q, _outstanding = values (client_queue, client_query_id, q, nil, OtherResolvError.new('Resolver closing!')) end } end |
#decrement_resolver_priority(res) ⇒ Object
TO BE CALLED IN A SYNCHRONIZED BLOCK
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# File 'lib/dnsruby/resolver.rb', line 1122 def decrement_resolver_priority(res) TheLog.debug("Decrementing resolver priority for #{res.server}\n") # @parent.single_res_mutex.synchronize { index = @parent.single_resolvers.index(res) if index < @parent.single_resolvers.length @parent.single_resolvers.delete(res) @parent.single_resolvers.insert(index+1,res) end # } end |
#demote_resolver(res) ⇒ Object
TO BE CALLED IN A SYNCHRONIZED BLOCK
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# File 'lib/dnsruby/resolver.rb', line 1134 def demote_resolver(res) TheLog.debug("Demoting resolver priority for #{res.server} to bottom\n") # @parent.single_res_mutex.synchronize { @parent.single_resolvers.delete(res) @parent.single_resolvers.push(res) # } end |
#generate_timeouts ⇒ Object
:nodoc: all
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# File 'lib/dnsruby/resolver.rb', line 874 def generate_timeouts # :nodoc: all # Create the timeouts for the query from the retry_times and retry_delay attributes. # These are created at the same time in case the parameters change during the life of the query. # # These should be absolute, rather than relative # The first value should be Time.now[ @parent.generate_timeouts(Time.now) end |
#handle_error_response(select_queue, query_id, error, response) ⇒ Object
:nodoc: all
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# File 'lib/dnsruby/resolver.rb', line 1053 def handle_error_response(select_queue, query_id, error, response) # :nodoc: all # Handle an error # @mutex.synchronize{ Dnsruby.log.debug{"handling error #{error.class}, #{error}"} # Check what sort of error it was : resolver, _msg, client_query_id, _retry_count = query_id _msg, client_queue, select_queue, outstanding = @query_list[client_query_id] if error.kind_of?(ResolvTimeout) # - if it was a timeout, then check which number it was, and how many retries are expected on that server # - if it was the last retry, on the last server, then return a timeout to the client (and clean up) # - otherwise, continue # Do we have any more packets to send to this resolver? decrement_resolver_priority(resolver) timeouts = @timeouts[client_query_id] if outstanding.empty? && timeouts && timeouts[1].values.empty? Dnsruby.log.debug{'Sending timeout to client'} (client_queue, client_query_id, select_queue, response, error) end elsif error.kind_of?(NXDomain) # - if it was an NXDomain, then return that to the client, and stop all new queries (and clean up) # send_result_and_stop_querying(client_queue, client_query_id, select_queue, response, error) increment_resolver_priority(resolver) unless response.cached (client_query_id) # @TODO@ Does the client want notified at this point? else # - if it was any other error, then remove that server from the list for that query # If a Too Many Open Files error, then don't remove, but let retry work. timeouts = @timeouts[client_query_id] unless error.to_s =~ /Errno::EMFILE/ Dnsruby.log.debug{"Removing #{resolver.server} from resolver list for this query"} if timeouts timeouts[1].each do |key, value| res = value[0] if res == resolver timeouts[1].delete(key) end end end # Also stick it to the back of the list for future queries demote_resolver(resolver) else Dnsruby.log.debug("NOT Removing #{resolver.server} due to Errno::EMFILE") end # - if it was the last server, then return an error to the client (and clean up) if outstanding.empty? && ((!timeouts) || (timeouts && timeouts[1].values.empty?)) # if outstanding.empty? Dnsruby.log.debug{'Sending error to client'} (client_queue, client_query_id, select_queue, response, error) end end # @TODO@ If we're still sending packets for this query, but none are outstanding, then # jumpstart the next query? # } end |
#handle_queue_event(queue, id) ⇒ Object
This method is called by the SelectThread (in the select thread) when the queue has a new item on it.
The queue interface is used to separate producer/consumer threads, but we're using it here in one thread.
It's probably a good idea to create a new "worker thread" to take items from the select thread queue and
call this method in the worker thread.
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# File 'lib/dnsruby/resolver.rb', line 976 def handle_queue_event(queue, id) # :nodoc: all # Time to process a new queue event. # If we get a callback for an ID we don't know about, don't worry - # just ignore it. It may be for a query we've already completed. # # So, get the next response from the queue (presuming there is one!) # # @TODO@ Tick could poll the queue and then call this method if needed - no need for observer interface. # @TODO@ Currently, tick and handle_queue_event called from select_thread - could have thread chuck events in to tick_queue. But then, clients would have to call in on other thread! # # So - two types of response : # 1) we've got a coherent response (or error) - stop sending more packets for that query! # 2) we've validated the response - it's ready to be sent to the client # # so need two more methods : # handleValidationResponse : basically calls send_result_and_stop_querying and # handleValidationError : does the same as handleValidationResponse, but for errors # can leave handleError alone # but need to change handleResponse to stop sending, rather than send_result_and_stop_querying. # # @TODO@ Also, we could really do with a MaxValidationTimeout - if validation not OK within # this time, then raise Timeout (and stop validation)? # # @TODO@ Also, should there be some facility to stop validator following same chain # concurrently? # # @TODO@ Also, should have option to speak only to configured resolvers (not follow authoritative chain) # if queue.empty? log_and_raise('Severe internal error - Queue empty in handle_queue_event') end event_id, event_type, response, error = queue.pop # We should remove this packet from the list of outstanding packets for this query _resolver, _msg, client_query_id, _retry_count = id if id != event_id log_and_raise("Serious internal error!! #{id} expected, #{event_id} received") end # @mutex.synchronize{ @parent.single_res_mutex.synchronize { if @query_list[client_query_id] == nil # print "Dead query response - ignoring\n" Dnsruby.log.debug{'Ignoring response for dead query'} return end _msg, _client_queue, _select_queue, outstanding = @query_list[client_query_id] if event_type == Resolver::EventType::RECEIVED || event_type == Resolver::EventType::ERROR unless outstanding.include?(id) log_and_raise("Query id not on outstanding list! #{outstanding.length} items. #{id} not on #{outstanding}") end outstanding.delete(id) end # } if event_type == Resolver::EventType::RECEIVED # if (event.kind_of?(Exception)) if error handle_error_response(queue, event_id, error, response) else # if event.kind_of?(Message) handle_response(queue, event_id, response) # else # Dnsruby.log.error('Random object #{event.class} returned through queue to Resolver') end elsif event_type == Resolver::EventType::VALIDATED if error handle_validation_error(queue, event_id, error, response) else handle_validation_response(queue, event_id, response) end elsif event_type == Resolver::EventType::ERROR handle_error_response(queue, event_id, error, response) else # print "ERROR - UNKNOWN EVENT TYPE IN RESOLVER : #{event_type}\n" TheLog.error("ERROR - UNKNOWN EVENT TYPE IN RESOLVER : #{event_type}") end } end |
#handle_response(select_queue, query_id, response) ⇒ Object
:nodoc: all
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# File 'lib/dnsruby/resolver.rb', line 1142 def handle_response(select_queue, query_id, response) # :nodoc: all # Handle a good response # Should also stick resolver more to the front of the list for future queries Dnsruby.log.debug('Handling good response') resolver, _msg, client_query_id, _retry_count = query_id increment_resolver_priority(resolver) unless response.cached # @mutex.synchronize{ _query, _client_queue, s_queue, _outstanding = @query_list[client_query_id] if s_queue != select_queue log_and_raise("Serious internal error : expected select queue #{s_queue}, got #{select_queue}") end (client_query_id) # @TODO@ Does the client want notified at this point? # client_queue.push([client_query_id, Resolver::EventType::RECEIVED, msg, nil]) # } end |
#handle_validation_error(select_queue, query_id, error, response) ⇒ Object
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# File 'lib/dnsruby/resolver.rb', line 1176 def handle_validation_error(select_queue, query_id, error, response) _resolver, _msg, client_query_id, _retry_count = query_id _query, client_queue, s_queue, _outstanding = @query_list[client_query_id] if s_queue != select_queue log_and_raise("Serious internal error : expected select queue #{s_queue}, got #{select_queue}") end # For some errors, we immediately send result. For others, should we retry? # Either : # handle_error_response(queue, event_id, error, response) # Or: send_result(client_queue, client_query_id, select_queue, response, error) # # end |
#handle_validation_response(select_queue, query_id, response) ⇒ Object
:nodoc: all
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# File 'lib/dnsruby/resolver.rb', line 1159 def handle_validation_response(select_queue, query_id, response) # :nodoc: all _resolver, _msg, client_query_id, _retry_count = query_id # @mutex.synchronize { _query, client_queue, s_queue, _outstanding = @query_list[client_query_id] if s_queue != select_queue log_and_raise("Serious internal error : expected select queue #{s_queue}, got #{select_queue}") end if response.rcode == RCode.NXDOMAIN send_result(client_queue, client_query_id, select_queue, response, NXDomain.new) else # @TODO@ Was there an error validating? Should we raise an exception for certain security levels? # This should be configurable by the client. send_result(client_queue, client_query_id, select_queue, response, nil) # } end end |
#increment_resolver_priority(res) ⇒ Object
TO BE CALLED IN A SYNCHRONIZED BLOCK
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# File 'lib/dnsruby/resolver.rb', line 1110 def increment_resolver_priority(res) TheLog.debug("Incrementing resolver priority for #{res.server}\n") # @parent.single_res_mutex.synchronize { index = @parent.single_resolvers.index(res) if index > 0 @parent.single_resolvers.delete(res) @parent.single_resolvers.insert(index-1,res) end # } end |
#reset_attributes ⇒ Object
:nodoc: all
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# File 'lib/dnsruby/resolver.rb', line 810 def reset_attributes # :nodoc: all # data structures # @mutex=Mutex.new @query_list = {} @timeouts = {} end |
#send_async(msg, client_queue, client_query_id = nil) ⇒ Object
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# File 'lib/dnsruby/resolver.rb', line 816 def send_async(msg, client_queue, client_query_id=nil) # This is the whole point of the Resolver class. # We want to use multiple SingleResolvers to run a query. # So we kick off a system with select_thread where we send # a query with a queue, but log ourselves as observers for that # queue. When a new response is pushed on to the queue, then the # select thread will call this class' handler method IN THAT THREAD. # When the final response is known, this class then sticks it in # to the client queue. q = Queue.new if client_query_id.nil? client_query_id = Time.now + rand(10000) end unless client_queue.kind_of?(Queue) log_and_raise('Wrong type for client_queue in Resolver# send_async') # @TODO@ Handle different queue tuples - push this to generic send_error method client_queue.push([client_query_id, ArgumentError.new('Wrong type of client_queue passed to Dnsruby::Resolver# send_async - should have been Queue, was #{client_queue.class}')]) return end unless msg.kind_of?Message Dnsruby.log.error{'Wrong type for msg in Resolver# send_async'} # @TODO@ Handle different queue tuples - push this to generic send_error method client_queue.push([client_query_id, ArgumentError.new("Wrong type of msg passed to Dnsruby::Resolver# send_async - should have been Message, was #{msg.class}")]) return end tick_needed = false # add to our data structures # @mutex.synchronize{ @parent.single_res_mutex.synchronize { tick_needed = true if @query_list.empty? if @query_list.has_key?(client_query_id) Dnsruby.log.error("Duplicate query id requested (#{client_query_id}") # @TODO@ Handle different queue tuples - push this to generic send_error method client_queue.push([client_query_id, ArgumentError.new('Client query ID already in use')]) return end outstanding = [] @query_list[client_query_id]=[msg, client_queue, q, outstanding] query_timeout = Time.now + @parent.query_timeout if @parent.query_timeout == 0 query_timeout = Time.now + 31536000 # a year from now end @timeouts[client_query_id] = [query_timeout, generate_timeouts] } # Now do querying stuff using SingleResolver # All this will be handled by the tick method (if we have 0 as the first timeout) st = SelectThread.instance st.add_observer(q, self) tick if tick_needed client_query_id end |
#send_result(client_queue, client_query_id, select_queue, msg, error) ⇒ Object
MUST BE CALLED IN A SYNCHRONIZED BLOCK!
Sends the result to the client's queue, and removes the queue observer from the select thread
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# File 'lib/dnsruby/resolver.rb', line 914 def send_result(client_queue, client_query_id, select_queue, msg, error) # :nodoc: all (client_query_id) # @TODO@ ! # We might still get some callbacks, which we should ignore st = SelectThread.instance st.remove_observer(select_queue, self) # @mutex.synchronize{ # Remove the query from all of the data structures @query_list.delete(client_query_id) # } # Return the response to the client client_queue.push([client_query_id, msg, error]) end |
#send_result_and_stop_querying(client_queue, client_query_id, select_queue, msg, error) ⇒ Object
MUST BE CALLED IN A SYNCHRONIZED BLOCK!
Send the result back to the client, and close the socket for that query by removing
the query from the select thread.
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# File 'lib/dnsruby/resolver.rb', line 899 def (client_queue, client_query_id, select_queue, msg, error) # :nodoc: all (client_query_id) send_result(client_queue, client_query_id, select_queue, msg, error) end |
#stop_querying(client_query_id) ⇒ Object
MUST BE CALLED IN A SYNCHRONIZED BLOCK!
Stops send any more packets for a client-level query
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# File 'lib/dnsruby/resolver.rb', line 907 def (client_query_id) # :nodoc: all @timeouts.delete(client_query_id) end |
#tick ⇒ Object
This method is called twice a second from the select loop, in the select thread.
It should arguably be called from another worker thread... (which also handles the queue)
Each tick, we check if any timeouts have occurred. If so, we take the appropriate action :
Return a timeout to the client, or send a new query
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# File 'lib/dnsruby/resolver.rb', line 931 def tick # :nodoc: all # Handle the tick # Do we have any retries due to be sent yet? # @mutex.synchronize{ @parent.single_res_mutex.synchronize { time_now = Time.now @timeouts.keys.each do |client_query_id| msg, client_queue, select_queue, outstanding = @query_list[client_query_id] query_timeout, timeouts = @timeouts[client_query_id] if query_timeout < Time.now # Time the query out (client_queue, client_query_id, select_queue, nil, ResolvTimeout.new('Query timed out')) next end timeouts_done = [] timeouts.keys.sort.each do |timeout| if timeout < time_now # Send the next query res, retry_count = timeouts[timeout] id = [res, msg, client_query_id, retry_count] Dnsruby.log.debug("Sending msg to #{res.server}") # We should keep a list of the queries which are outstanding outstanding.push(id) timeouts_done.push(timeout) timeouts.delete(timeout) # Pick a new QID here @TODO@ !!! # msg.header.id = rand(65535); # print "New query : #{new_msg}\n" res.send_async(msg, select_queue, id) else break end end timeouts_done.each { |t| timeouts.delete(t) } end } end |