Class: OpenC3::UdpReadWriteSocket

Inherits:
Object
  • Object
show all
Defined in:
lib/openc3/io/udp_sockets.rb

Direct Known Subclasses

UdpReadSocket, UdpWriteSocket

Constant Summary collapse

HOST_0_0_0_0 = 
'0.0.0.0'
WRITE_FLAGS =

MSG_DONTWAIT is not defined on Windows where sends are left blocking

Socket.const_defined?('MSG_DONTWAIT') ? Socket::MSG_DONTWAIT : 0

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(bind_port = 0, bind_address = HOST_0_0_0_0, external_port = nil, external_address = nil, multicast_interface_address = nil, ttl = 1, read_multicast = true, write_multicast = true, connect_socket = true) ⇒ UdpReadWriteSocket

Returns a new instance of UdpReadWriteSocket.

Parameters:

  • bind_port (Integer[ Port to write data out from and receive data on (0 = randomly assigned)) (defaults to: 0) —

    ind_port [Integer[ Port to write data out from and receive data on (0 = randomly assigned)

  • bind_address (String) (defaults to: HOST_0_0_0_0) —

    Local address to bind to (0.0.0.0 = All local addresses)

  • external_port (Integer) (defaults to: nil) —

    External port to write to

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

    External host to send data to

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

    Local outgoing interface to send multicast packets from

  • ttl (Integer) (defaults to: 1) —

    Time To Live for outgoing multicast packets

  • read_multicast (Boolean) (defaults to: true) —

    Whether or not to try to read from the external address as multicast

  • write_multicast (Boolean) (defaults to: true) —

    Whether or not to write to the external address as multicast

  • connect_socket (Boolean) (defaults to: true) —

    Whether to connect the socket to the external address. If false, writes explicitly address each datagram so reads can accept datagrams from any source.



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# File 'lib/openc3/io/udp_sockets.rb', line 43

def initialize(
  bind_port = 0,
  bind_address = HOST_0_0_0_0,
  external_port = nil,
  external_address = nil,
  multicast_interface_address = nil,
  ttl = 1,
  read_multicast = true,
  write_multicast = true,
  connect_socket = true
)

  @socket = UDPSocket.new
  @external_address = external_address
  @external_port = external_port
  @connect_socket = connect_socket
  # Resolve the destination once at creation time so writes don't pay for a
  # (potentially blocking) name lookup on every datagram
  @external_sockaddr = nil
  if !connect_socket and external_address and external_port
    # Explicitly resolve IPv4 because UDPSocket is an AF_INET socket and
    # sockaddr_in would otherwise hand back an IPv6 address for names like localhost
    ip_address = Socket.getaddrinfo(external_address, nil, Socket::AF_INET, Socket::SOCK_DGRAM)[0][3]
    @external_sockaddr = Socket.sockaddr_in(external_port, ip_address)
  end

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

  # Bind to local address and port - This sets recv port, write_src port, recv_address, and write_src_address
  @socket.bind(bind_address, bind_port) if bind_address and bind_port

  # Default send to the specified address and port
  @socket.connect(external_address, external_port) if connect_socket and external_address and external_port

  # Handle multicast
  if UdpReadWriteSocket.multicast?(external_address)
    if write_multicast
      # 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(multicast_interface_address).hton
      ) if multicast_interface_address
    end

    # Receive messages sent to the multicast address
    if read_multicast
      multicast_interface_address = HOST_0_0_0_0 unless multicast_interface_address
      membership = IPAddr.new(external_address).hton + IPAddr.new(multicast_interface_address).hton
      @socket.setsockopt(Socket::IPPROTO_IP, Socket::IP_ADD_MEMBERSHIP, membership)
    end
  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/openc3/io/udp_sockets.rb', line 151

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

Class Method Details

.multicast?(host, port = nil) ⇒ Boolean

Returns Whether the hostname is multicast.

Parameters:

  • host (String) —

    Machine name or IP address

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

    Port (unused, kept for backwards compatibility)

Returns:

  • (Boolean) —

    Whether the hostname is multicast



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# File 'lib/openc3/io/udp_sockets.rb', line 158

def self.multicast?(host, port = nil)
  return false if host.nil?

  begin
    Addrinfo.udp(host, 0).ipv4_multicast?
  rescue SocketError, ArgumentError
    # Hostname isn't resolvable so it can't be a multicast address we handle.
    # Reads don't need the hostname at all so don't fail creating the socket.
    false
  end
end

Instance Method Details

#read(read_timeout = nil) ⇒ Object

Parameters:

  • read_timeout (Float) (defaults to: nil) —

    Time in seconds to wait for the read to complete



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# File 'lib/openc3/io/udp_sockets.rb', line 135

def read(read_timeout = nil)
  data = nil
  begin
    data, _ = @socket.recvfrom_nonblock(65536)
  rescue Errno::EAGAIN, Errno::EWOULDBLOCK
    result = IO.fast_select([@socket], nil, nil, read_timeout)
    if result
      retry
    else
      raise Timeout::Error, "Read Timeout"
    end
  end
  data
end

#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/openc3/io/udp_sockets.rb', line 103

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
      if @external_sockaddr
        # send is used rather than sendmsg_nonblock because sendmsg is not
        # implemented on Windows
        bytes_sent = @socket.send(data_to_send, WRITE_FLAGS, @external_sockaddr)
      else
        bytes_sent = @socket.write_nonblock(data_to_send)
      end
    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