Method: Net::DNS::MDNS::Responder#initialize

Defined in:
lib/net/dns/mdns.rb

#initialize ⇒ Responder

Returns a new instance of Responder.



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# File 'lib/net/dns/mdns.rb', line 427

def initialize
  @log = Logger.new(STDERR)

  @log.level = Logger::ERROR

  @mutex = Mutex.new

  @cache = Cache.new

  @queries = []

  @services = []

  @hostname = Name.create(Socket.gethostname)
  @hostname.absolute = true
  @hostaddr = Socket.getaddrinfo(@hostname.to_s, 0, Socket::AF_INET, Socket::SOCK_STREAM)[0][3]
  @hostrr   = [ @hostname, 240, IN::A.new(@hostaddr) ]
  @hostaddr = IPAddr.new(@hostaddr).hton

  debug( "start" )

  # TODO - I'm not sure about how robust this is. A better way to find the default
  # ifx would be to do:
  #   s = UDPSocket.new
  #   s.connect(any addr, any port)
  #   s.getsockname => struct sockaddr_in => ip_addr
  # But parsing a struct sockaddr_in is a PITA in ruby.

  @sock = UDPSocket.new

  # Set the close-on-exec flag, if supported.
  if Fcntl.constants.include? 'F_SETFD'
    @sock.fcntl(Fcntl::F_SETFD, 1)
  end

  # Allow 5353 to be shared.
  so_reuseport = 0x0200
  # The definition on OS X, where it is required, and where the shipped
  # ruby version (1.6) does not have Socket::SO_REUSEPORT. The definition
  # seems to be shared by at least some other BSD-derived stacks.
  if Socket.constants.include? 'SO_REUSEPORT'
    so_reuseport = Socket::SO_REUSEPORT
  end
  begin
    @sock.setsockopt(Socket::SOL_SOCKET, so_reuseport, 1)
  rescue
    warn( "set SO_REUSEPORT raised #{$!}, try SO_REUSEADDR" )
    so_reuseport = Socket::SO_REUSEADDR
    @sock.setsockopt(Socket::SOL_SOCKET, so_reuseport, 1)
  end

  # Request dest addr and ifx ids... no.

  # Bind to our port.
  @sock.bind(Socket::INADDR_ANY, Port)

  # Join the multicast group.
  #  option is a struct ip_mreq { struct in_addr, struct in_addr }
  ip_mreq =  IPAddr.new(Addr).hton + @hostaddr
  @sock.setsockopt(Socket::IPPROTO_IP, Socket::IP_ADD_MEMBERSHIP, ip_mreq)
  @sock.setsockopt(Socket::IPPROTO_IP, Socket::IP_MULTICAST_IF, @hostaddr)

  # Set IP TTL for outgoing packets.
  @sock.setsockopt(Socket::IPPROTO_IP, Socket::IP_TTL, 255)
  @sock.setsockopt(Socket::IPPROTO_IP, Socket::IP_MULTICAST_TTL, 255)

  # Apple source makes it appear that optval may need to be a "char" on
  # some systems:
  #  @sock.setsockopt(Socket::IPPROTO_IP, Socket::IP_MULTICAST_TTL, 255 as int)
  #     - or -
  #  @sock.setsockopt(Socket::IPPROTO_IP, Socket::IP_MULTICAST_TTL, 255 as byte)

  # Start responder and cacher threads.

  @waketime = nil

  @cacher_thrd = Thread.new do
    begin
      cacher_loop
    rescue
      error( "cacher_loop exited with #{$!}" )
      $!.backtrace.each do |e| error(e) end
    end
  end

  @responder_thrd = Thread.new do
    begin
      responder_loop
    rescue
      error( "responder_loop exited with #{$!}" )
      $!.backtrace.each do |e| error(e) end
    end
  end
end