Class: SDN::Message

Inherits:
Object
  • Object
show all
Includes:
Helpers
Defined in:
lib/sdn/message.rb,
lib/sdn/message/get.rb,
lib/sdn/message/set.rb,
lib/sdn/message/post.rb,
lib/sdn/message/control.rb,
lib/sdn/message/helpers.rb,
lib/sdn/message/ilt2/get.rb,
lib/sdn/message/ilt2/set.rb,
lib/sdn/message/ilt2/post.rb,
lib/sdn/message/ilt2/master_control.rb

Overview

Base type for all SDN protocol frames and message-specific serializers/parsers.

Defined Under Namespace

Modules: Helpers, ILT2 Classes: Ack, GetGroupAddr, GetMotorDirection, GetMotorIP, GetMotorLimits, GetMotorPosition, GetMotorRollingSpeed, GetMotorStatus, GetNetworkLock, GetNodeAddr, GetNodeAppVersion, GetNodeLabel, GetNodeSerialNumber, GetNodeStackVersion, Lock, Move, MoveOf, MoveTo, Nack, PostGroupAddr, PostMotorDirection, PostMotorIP, PostMotorLimits, PostMotorPosition, PostMotorRollingSpeed, PostMotorStatus, PostNetworkLock, PostNodeAddr, PostNodeAppVersion, PostNodeLabel, PostNodeSerialNumber, PostNodeStackVersion, SetFactoryDefault, SetGroupAddr, SetMotorDirection, SetMotorIP, SetMotorLimits, SetMotorRollingSpeed, SetNetworkLock, SetNodeLabel, SimpleRequest, Stop, UnknownMessage, Wink

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Helpers

#checksum, #from_number, #from_string, #group_address?, #node_type_from_number, #node_type_to_number, #node_type_to_string, #parse_address, #print_address, #to_number, #to_string, #transform_param

Constructor Details

#initialize(node_type: nil, ack_requested: false, src: nil, dest: nil) ⇒ Message

Builds a message envelope with optional addressing and acknowledgement behavior.

Parameters:

  • node_type (Symbol, Integer, nil) (defaults to: nil) —

    originating node type

  • ack_requested (true, false) (defaults to: false) —

    whether the receiver should acknowledge the message

  • src ((Integer, Integer, Integer), nil) (defaults to: nil) —

    source address bytes

  • dest ((Integer, Integer, Integer), nil) (defaults to: nil) —

    destination address bytes



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# File 'lib/sdn/message.rb', line 128

def initialize(node_type: nil, ack_requested: false, src: nil, dest: nil)
  @node_type = node_type || 0
  @ack_requested = ack_requested
  if src.nil? && !dest.nil? && group_address?(dest)
    src = dest
    dest = nil
  end
  @src = src || [0, 0, 1]
  @dest = dest || [0, 0, 0]
end

Instance Attribute Details

#ack_requested ⇒ true, false

Whether this message requests an acknowledgement.

Returns:

  • (true, false) 


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# File 'lib/sdn/message.rb', line 110

def ack_requested
  @ack_requested
end

#dest ⇒ (Integer, Integer, Integer)

Destination address for the message.

Returns:

  • ((Integer, Integer, Integer)) 


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# File 'lib/sdn/message.rb', line 120

def dest
  @dest
end

#node_type ⇒ Symbol, Integer

Message sender node type.

Returns:

  • (Symbol, Integer) 


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# File 'lib/sdn/message.rb', line 105

def node_type
  @node_type
end

#src ⇒ (Integer, Integer, Integer)

Source address for the message.

Returns:

  • ((Integer, Integer, Integer)) 


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# File 'lib/sdn/message.rb', line 115

def src
  @src
end

Class Method Details

.expected_response?(message) ⇒ true, false

Determines whether a received message satisfies the expected response for this request type.

Parameters:

Returns:

  • (true, false) 


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# File 'lib/sdn/message.rb', line 26

def expected_response?(message)
  if /::Get([A-Za-z]+)/.match?(name)
    message.class.name == name.sub("::Get", "::Post") # rubocop:disable Style/ClassEqualityComparison
  else
    message.is_a?(Ack) || message.is_a?(Nack)
  end
end

.parse(data) ⇒ (SDN::Message, Integer)

Attempts to parse the first valid SDN message from a byte stream.

Parameters:

  • data (<Integer>) —

    raw bytes buffered from the transport

Returns:

  • ((SDN::Message, Integer)) —

    parsed message and consumed byte count



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# File 'lib/sdn/message.rb', line 39

def parse(data)
  offset = -1
  msg = length = ack_requested = message_class = nil
  # we loop here scanning for a valid message
  loop do
    offset += 1
    # give these weird messages a chance
    result = ILT2::MasterControl.parse(data)
    return result if result

    return [nil, 0] if data.length - offset < 11

    msg = to_number(data[offset])
    length = to_number(data[offset + 1])
    ack_requested = length & 0x80 == 0x80
    length &= 0x7f
    # impossible message
    next if length < 11 || length > 43
    # don't have enough data for what this message wants;
    # it could be garbage on the line so keep scanning
    next if length > data.length - offset

    message_class = message_map[msg] || UnknownMessage

    calculated_sum = checksum(data.slice(offset, length - 2))
    read_sum = data.slice(offset + length - 2, 2)
    next unless read_sum == calculated_sum

    break
  end

  node_type = node_type_from_number(to_number(data[offset + 2]))
  src = transform_param(data.slice(offset + 3, 3))
  dest = transform_param(data.slice(offset + 6, 3))
  begin
    result = message_class.new(node_type:, ack_requested:, src:, dest:)
    result.parse(data.slice(offset + 9, length - 11))
    result.msg = msg if message_class == UnknownMessage
  rescue ArgumentError => e
    SDN.logger.warn "Discarding illegal message of type #{message_class.name}: #{e}"
    result = nil
  end
  [result, offset + length]
end

Instance Method Details

#==(other) ⇒ true, false

Returns:

  • (true, false) 


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# File 'lib/sdn/message.rb', line 167

def ==(other)
  serialize == other.serialize
end

#inspect ⇒ String Also known as: to_s

Returns:

  • (String) 


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# File 'lib/sdn/message.rb', line 172

def inspect
  format("#<%s @node_type=%s, @ack_requested=%s, @src=%s, @dest=%s%s>",
         self.class.name,
         node_type_to_string(node_type),
         ack_requested,
         print_address(src),
         print_address(dest),
         class_inspect)
end

#parse(params) ⇒ void

This method returns an undefined value.

Parses protocol-specific parameter bytes into this message instance.

Parameters:

  • params (<Integer>) —

    raw parameter bytes

Raises:



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# File 'lib/sdn/message.rb', line 146

def parse(params)
  return unless self.class.const_defined?(:PARAMS_LENGTH) && params.length != self.class.const_get(:PARAMS_LENGTH)

  raise MalformedMessage, "unrecognized params for #{self.class.name}: #{params.map do |b|
                                                                           format("%02x", b)
                                                                         end}"
end

#serialize ⇒ String

Serializes the message to a packed SDN frame.

Returns:

  • (String) —

    binary protocol frame



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# File 'lib/sdn/message.rb', line 157

def serialize
  result = transform_param(node_type_to_number(node_type)) + transform_param(src) + transform_param(dest) + params
  length = result.length + 4
  length |= 0x80 if ack_requested
  result = transform_param(self.class.const_get(:MSG)) + transform_param(length) + result
  result.concat(checksum(result))
  result.pack("C*")
end