Class: Cosmos::UdpWriteSocket

Inherits:
Object
  • Object
show all
Defined in:
lib/cosmos/io/udp_sockets.rb

Overview

Creates a UDPSocket and implements a non-blocking write.

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(dest_address, dest_port, src_port = nil, interface_address = nil, ttl = 1, bind_address = "0.0.0.0") ⇒ UdpWriteSocket

Returns a new instance of UdpWriteSocket.

Parameters:

  • dest_address (String) —

    Host to send data to

  • dest_port (Integer) —

    Port to send data to

  • src_port (Integer[ Port to send data out from) (defaults to: nil) —

    rc_port [Integer[ Port to send data out from

  • interface_address (String) (defaults to: nil) —

    Local outgoing interface to send from

  • ttl (Integer) (defaults to: 1) —

    Time To Live for outgoing packets



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# File 'lib/cosmos/io/udp_sockets.rb', line 29

def initialize(dest_address,
               dest_port,
               src_port = nil,
               interface_address = nil,
               ttl = 1,
               bind_address = "0.0.0.0")
  @socket = UDPSocket.new

  # Basic setup to reuse address
  @socket.setsockopt(Socket::SOL_SOCKET, Socket::SO_REUSEADDR, 1)

  # Set source port if given
  @socket.bind(bind_address, src_port) if src_port

  # Default send to the specified address and port
  @socket.connect(dest_address, dest_port)

  # Handle multicast
  if UdpWriteSocket.multicast?(dest_address)
    # Basic setup set time to live
    @socket.setsockopt(Socket::IPPROTO_IP, Socket::IP_MULTICAST_TTL, ttl.to_i)

    # Set outgoing interface
    @socket.setsockopt(Socket::IPPROTO_IP, Socket::IP_MULTICAST_IF, IPAddr.new(interface_address).hton) if interface_address
  end
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *args, &block) ⇒ Object

Defer all methods to the UDPSocket



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# File 'lib/cosmos/io/udp_sockets.rb', line 82

def method_missing(method, *args, &block)
  @socket.__send__(method, *args, &block)
end

Class Method Details

.multicast?(host) ⇒ Boolean

Returns Whether the hostname is multicast.

Parameters:

  • host (String) —

    Machine name or IP address

Returns:

  • (Boolean) —

    Whether the hostname is multicast



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# File 'lib/cosmos/io/udp_sockets.rb', line 88

def self.multicast?(host)
  return false if host.nil?
  # Look up address
  _, _, _, *address_list = Socket.gethostbyname(host)
  first_addr_byte = 0
  address_list.each do |address|
    if address.length == 4
      first_addr_byte = address.getbyte(0)
      break
    end
  end

  if (first_addr_byte >= 224) && (first_addr_byte <= 239)
    true
  else
    false
  end
end

Instance Method Details

#write(data, write_timeout = 10.0) ⇒ Object

Parameters:

  • data (String) —

    Binary data to send

  • write_timeout (Float) (defaults to: 10.0) —

    Time in seconds to wait for the data to send



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# File 'lib/cosmos/io/udp_sockets.rb', line 58

def write(data, write_timeout = 10.0)
  num_bytes_to_send = data.length
  total_bytes_sent  = 0
  bytes_sent = 0
  data_to_send = data

  loop do
    begin
      bytes_sent = @socket.write_nonblock(data_to_send)
    rescue Errno::EAGAIN, Errno::EWOULDBLOCK
      result = IO.fast_select(nil, [@socket], nil, write_timeout)
      if result
        retry
      else
        raise Timeout::Error, "Write Timeout"
      end
    end
    total_bytes_sent += bytes_sent
    break if total_bytes_sent >= num_bytes_to_send
    data_to_send = data[total_bytes_sent..-1]
  end
end