Class: RubyDNS::Server

Inherits:
Object
  • Object
show all
Includes:
Celluloid::IO
Defined in:
lib/rubydns/server.rb

Direct Known Subclasses

RuleBasedServer

Constant Summary collapse

DEFAULT_INTERFACES =

The default server interfaces

[[:udp, "0.0.0.0", 53], [:tcp, "0.0.0.0", 53]]

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Server

Instantiate a server with a block

server = Server.new do match(/server.mydomain.com/, IN::A) do |transaction| transaction.respond!("1.2.3.4") end end



55
56
57
58
59
60
61
62
 
# File 'lib/rubydns/server.rb', line 55

def initialize(options = {})
  @handlers = []
  
  @logger = options[:logger] || Celluloid.logger
  @interfaces = options[:listen] || DEFAULT_INTERFACES
  
  @origin = options[:origin] || '.'
end

Instance Attribute Details

#logger ⇒ Object

Returns the value of attribute logger.



67
68
69
 
# File 'lib/rubydns/server.rb', line 67

def logger
  @logger
end

#origin ⇒ Object

Records are relative to this origin:



65
66
67
 
# File 'lib/rubydns/server.rb', line 65

def origin
  @origin
end

Instance Method Details

#fire(event_name) ⇒ Object

Fire the named event as part of running the server.



70
71
 
# File 'lib/rubydns/server.rb', line 70

def fire(event_name)
end

#process(name, resource_class, transaction) ⇒ Object

Give a name and a record type, try to match a rule and use it for processing the given arguments.

Raises:

  • (NotImplementedError) 


78
79
80
 
# File 'lib/rubydns/server.rb', line 78

def process(name, resource_class, transaction)
  raise NotImplementedError.new
end

#process_query(query, options = {}, &block) ⇒ Object

Process an incoming DNS message. Returns a serialized message to be sent back to the client.



83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
 
# File 'lib/rubydns/server.rb', line 83

def process_query(query, options = {}, &block)
  start_time = Time.now
  
  # Setup response
  response = Resolv::DNS::Message::new(query.id)
  response.qr = 1                 # 0 = Query, 1 = Response
  response.opcode = query.opcode  # Type of Query; copy from query
  response.aa = 1                 # Is this an authoritative response: 0 = No, 1 = Yes
  response.rd = query.rd          # Is Recursion Desired, copied from query
  response.ra = 0                 # Does name server support recursion: 0 = No, 1 = Yes
  response.rcode = 0              # Response code: 0 = No errors
  
  transaction = nil
  
  begin
    query.question.each do |question, resource_class|
      begin
        question = question.without_origin(@origin)
        
        @logger.debug {"<#{query.id}> Processing question #{question} #{resource_class}..."}
        
        transaction = Transaction.new(self, query, question, resource_class, response, options)
        
        transaction.process
      rescue Resolv::DNS::OriginError
        # This is triggered if the question is not part of the specified @origin:
        @logger.debug {"<#{query.id}> Skipping question #{question} #{resource_class} because #{$!}"}
      end
    end
  rescue Celluloid::ResumableError
    raise
  rescue StandardError => error
    @logger.error "<#{query.id}> Exception thrown while processing #{transaction}!"
    RubyDNS.log_exception(@logger, error)
  
    response.rcode = Resolv::DNS::RCode::ServFail
  end
  
  end_time = Time.now
  @logger.debug {"<#{query.id}> Time to process request: #{end_time - start_time}s"}
  
  return response
end

#run ⇒ Object

By default the server runs on port 53, both TCP and UDP, which is usually a priviledged port and requires root access to bind. You can change this by specifying options[:listen] which should contain an array of [protocol, interface address, port] specifications.

INTERFACES = [[:udp, "0.0.0.0", 5300]] RubyDNS::run_server(:listen => INTERFACES) do ... end

You can specify already connected sockets if need be:

socket = UDPSocket.new; socket.bind("0.0.0.0", 53) Process::Sys.setuid(server_uid) INTERFACES = [socket]



141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
 
# File 'lib/rubydns/server.rb', line 141

def run
  @logger.info "Starting RubyDNS server (v#{RubyDNS::VERSION})..."
  
  fire(:setup)
  
  # Setup server sockets
  @interfaces.each do |spec|
    if spec.is_a?(BasicSocket)
      spec.do_not_reverse_lookup
      protocol = spec.getsockopt(Socket::SOL_SOCKET, Socket::SO_TYPE).unpack("i")[0]
      ip = spec.local_address.ip_address
      port = spec.local_address.ip_port
      
      case protocol
      when Socket::SOCK_DGRAM
        @logger.info "<> Attaching to pre-existing UDP socket #{ip}:#{port}"
        link UDPSocketHandler.new(self, UDPSocketWrapper.new(spec))
      when Socket::SOCK_STREAM
        @logger.info "<> Attaching to pre-existing TCP socket #{ip}:#{port}"
        link TCPSocketHandler.new(self, TCPServerWrapper.new(spec))
      else
        raise ArgumentError.new("Unknown socket protocol: #{protocol}")
      end
    elsif spec[0] == :udp
      @logger.info "<> Listening on #{spec.join(':')}"
      link UDPHandler.new(self, spec[1], spec[2])
    elsif spec[0] == :tcp
      @logger.info "<> Listening on #{spec.join(':')}"
      link TCPHandler.new(self, spec[1], spec[2])
    else
      raise ArgumentError.new("Invalid connection specification: #{spec.inspect}")
    end
  end
  
  fire(:start)
end

#shutdown ⇒ Object 



73
74
75
 
# File 'lib/rubydns/server.rb', line 73

def shutdown
  fire(:stop)
end