Class: OverSIP::WebSocket::WsFraming

Inherits:
Object
  • Object
show all
Includes:
Logger
Defined in:
lib/oversip/websocket/ws_framing.rb

Constant Summary collapse

OPCODE = 
{
  0  => :continuation,
  1  => :text,
  2  => :binary,
  8  => :close,
  9  => :ping,
  10 => :pong
}
KEEPALIVE_PING_FRAME = 
keepalive_ping_frame
LOG_ID = 
"WsFraming"

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Logger

fg_system_msg2str, load_methods

Constructor Details

#initialize(connection, buffer) ⇒ WsFraming

Returns a new instance of WsFraming.



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# File 'lib/oversip/websocket/ws_framing.rb', line 37

def initialize connection, buffer
  @connection = connection
  @buffer = buffer
  @utf8_validator = ::OverSIP::WebSocket::FramingUtils::Utf8Validator.allocate
  @state = :init
end

Instance Attribute Details

#ws_app=(value) ⇒ Object (writeonly)

Sets the attribute ws_app

Parameters:

  • value —

    the value to set the attribute ws_app to.



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# File 'lib/oversip/websocket/ws_framing.rb', line 28

def ws_app=(value)
  @ws_app = value
end

Class Method Details

.class_init ⇒ Object 



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# File 'lib/oversip/websocket/ws_framing.rb', line 23

def self.class_init
  @@max_frame_size = ::OverSIP.configuration[:websocket][:max_ws_frame_size]
end

Instance Method Details

#continuation_frame? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/oversip/websocket/ws_framing.rb', line 364

def continuation_frame?
  @opcode == 0
end

#control_frame? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/oversip/websocket/ws_framing.rb', line 354

def control_frame?
  @opcode > 2
end

#do_keep_alive(interval) ⇒ Object 



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# File 'lib/oversip/websocket/ws_framing.rb', line 45

def do_keep_alive interval
  @keep_alive_timer = ::EM::PeriodicTimer.new(interval) do
    unless @connection.error?  # Ensure it.
      log_system_debug "sending keep-alive ping frame"  if $oversip_debug
      @connection.send_data KEEPALIVE_PING_FRAME
    else
      @keep_alive_timer.cancel
    end
  end
end

#log_id ⇒ Object 



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# File 'lib/oversip/websocket/ws_framing.rb', line 32

def log_id
  LOG_ID
end

#receive_data ⇒ Object 



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# File 'lib/oversip/websocket/ws_framing.rb', line 57

def receive_data
  while (case @state
    when :init
      return false  if @buffer.size < 2

      byte1 = @buffer.read(1).getbyte(0)
      byte2 = @buffer.read(1).getbyte(0)

      # FIN is the bit 0.
      @fin = (byte1 & 0b10000000) == 0b10000000

      # RSV1-3 are bits 1-3.
      @rsv1 = (byte1 & 0b01000000) == 0b01000000
      @rsv2 = (byte1 & 0b00100000) == 0b00100000
      @rsv3 = (byte1 & 0b00010000) == 0b00010000

      if @rsv1 or @rsv2 or @rsv3
        log_system_notice "frame has RSV bits set, clossing the connection"
        @connection.close 1002, "RSV bit set not supported"
        return false
      end

      # opcode are bits 4-7.
      @opcode = byte1 & 0b00001111
      unless (@sym_opcode = OPCODE[@opcode])
        @connection.close 1002, "unknown opcode=#{@opcode}"
        return false
      end

      # MASK is bit 8.
      @mask = (byte2 & 0b10000000) == 0b10000000
      unless @mask
        @connection.close 1002, "MASK bit not set"
        return false
      end

      # payload_len are bits 9-15.
      length = byte2 & 0b01111111

      case length
      # Length defined by 8 bytes.
      when 127
        @state = :payload_length_8_bytes
      # Length defined by 2 bytes.
      when 126
        @state = :payload_length_2_bytes
      # Length defined by already received 7 bits.
      else
        @payload_length = length
        @state = :masking_key
      end

      @payload = nil
      true

    when :payload_length_2_bytes
      return false  if @buffer.size < 2

      # Get the payload length and remove first two bytes fro
      # the buffer at the same time.
      @payload_length = @buffer.read(2).unpack('n').first

      @state = :masking_key
      true

    when :payload_length_8_bytes
      return false  if @buffer.size < 8

      # Get the payload length.
      # NOTE: Just take the last 4 bytes (4 GB frame is enough!!!),
      # Check that first 4 bytes are 0000. If not then the frame is bigger
      # than 4 GB and must be rejected!

      if @buffer.read(4).unpack('N').first != 0
        log_system_notice "frame size bigger than 4 GB, rejected"
        @connection.close 1008
        return false
      end

      @payload_length = @buffer.read(4).unpack('N').first

      @state = :masking_key
      true

    when :masking_key
      return false  if @buffer.size < 4

      # Get the masking key (4 bytes) and remove first 4 bytes
      # from the buffer.
      @masking_key = @buffer.read(4)

      @state = :check_frame
      true

    when :check_frame
      # All control frames MUST have a payload length of 125 bytes or
      # less and MUST NOT be fragmented.
      if control_frame? and @payload_length > 125
        log_system_notice "received invalid control frame (payload_length > 125), sending close frame"
        @connection.close 1002
        return false
      end

      if control_frame? and not @fin
        log_system_notice "received invalid control frame (FIN=0), sending close frame"
        @connection.close 1002, "forbidden FIN=0 in control frame"
        return false
      end

      # A continuation frame can only arrive if previously a text/binary frame
      # arrived with FIN=0.
      if continuation_frame? and not @msg_sym_opcode
        log_system_notice "invalid continuation frame received (no previous unfinished message), sending close frame"
        @connection.close 1002, "invalid continuation frame received"
        return false
      end

      # If a previous frame had FIN=0 and opcode=text/binary, then it cannot arrive
      # a new frame with opcode=text/binary.
      if @msg_sym_opcode and text_or_binary_frame?
        log_system_notice "invalid text/binary frame received (expecting a continuation frame), sending close frame"
        @connection.close 1002, "expected a continuation frame"
        return false
      end

      # Check max frame size.
      if @payload_length > @@max_frame_size
        @connection.close 1009, "frame too big"
        return false
      end

      @state = :payload_data
      true

    when :payload_data
      return false  if @buffer.size < @payload_length

      unless @payload_length.zero?
        # NOTE: @payload will always be Encoding::BINARY
        @payload = ::OverSIP::WebSocket::FramingUtils.unmask @buffer.read(@payload_length), @masking_key
      end
      # NOTE: @payload could be nil.

      @state = :process_frame
      true

    when :process_frame
      # Set it here as it could be changed later in this block.
      @state = :init

      case @sym_opcode

      when :text
        log_system_debug "received text frame: FIN=#{@fin}, RSV1-3=#{@rsv1}/#{@rsv2}/#{@rsv3}, payload_length=#{@payload_length}"  if $oversip_debug

        # Store the opcode of the first frame (if there is more frames for same message
        # they will have opcode=continuation).
        @msg_sym_opcode = @sym_opcode

        # Reset the UTF8 validator.
        @utf8_validator.reset

        if @payload
          if (valid_utf8 = @utf8_validator.validate(@payload)) == false
            log_system_notice "received single text frame contains invalid UTF-8, closing the connection"
            @connection.close 1007, "single text frame contains invalid UTF-8"
            return false
          end

          if @fin and not valid_utf8
            log_system_notice "received single text frame contains incomplete UTF-8, closing the connection"
            @connection.close 1007, "single text frame contains incomplete UTF-8"
            return false
          end

          # If @ws_app.receive_payload_data returns false it means that total
          # message size is too big.
          unless @ws_app.receive_payload_data @payload
            @connection.close 1009, "message too big"
            return false
          end
        end

        # If message is finished tell it to the WS application.
        if @fin
          @ws_app.message_done @msg_sym_opcode
          @msg_sym_opcode = nil
        end

      when :binary
        log_system_debug "received binary frame: FIN=#{@fin}, RSV1-3=#{@rsv1}/#{@rsv2}/#{@rsv3}, payload_length=#{@payload_length}"  if $oversip_debug

        # Store the opcode of the first frame (if there is more frames for same message
        # they will have opcode=continuation).
        @msg_sym_opcode = @sym_opcode

        if @payload
          # If @ws_app.receive_payload_data returns false it means that total
          # message size is too big.
          unless @ws_app.receive_payload_data @payload
            @connection.close 1009, "message too big"
            return false
          end
        end

        # If message is finished tell it to the WS application.
        if @fin
          @ws_app.message_done @msg_sym_opcode
          @msg_sym_opcode = nil
        end

      when :continuation
        log_system_debug "received continuation frame: FIN=#{@fin}, RSV1-3=#{@rsv1}/#{@rsv2}/#{@rsv3}, payload_length=#{@payload_length}"  if $oversip_debug

        if @payload
          if @msg_sym_opcode == :text
            if (valid_utf8 = @utf8_validator.validate(@payload)) == false
              log_system_notice "received continuation text frame contains invalid UTF-8, closing the connection"
              @connection.close 1007, "continuation text frame contains invalid UTF-8"
              return false
            end

            if @fin and not valid_utf8
              log_system_notice "received continuation final text frame contains incomplete UTF-8, closing the connection"
              @connection.close 1007, "continuation final text frame contains incomplete UTF-8"
              return false
            end
          end

          return false  unless @ws_app.receive_payload_data @payload
        end

        # If message is finished tell it to the WS application.
        if @fin
          @ws_app.message_done @msg_sym_opcode
          @msg_sym_opcode = nil
        end

      when :close
        if @payload_length >= 2
          status = ""
          status << @payload.getbyte(0) << @payload.getbyte(1)
          status =  status.unpack('n').first
          if (reason = @payload[2..-1])
            # Reset the UTF8 validator.
            @utf8_validator.reset

            # The UTF-8 validator returns:
            # - true: Valid UTF-8 string.
            # - nil: Valid but not terminated UTF-8 string.
            # - false: Invalid UTF-8 string.
            # So it must be true for the close frame reason.
            unless @utf8_validator.validate(reason)
              log_system_notice "received close frame with invalid UTF-8 data in the reason: status=#{status.inspect}"
              @connection.close 1007, "close frame reason contains incomplete UTF-8"
              return false
            end
          end
        else
          status = nil
        end

        case status
        when 1002
          log_system_notice "received close frame due to WS protocol error: status=1002, reason=#{reason.inspect}"
        when 1003
          log_system_notice "received close frame due to sent data type: status=1003, reason=#{reason.inspect}"
        when 1007
          log_system_notice "received close frame due to non valid UTF-8 data sent: status=1007, reason=#{reason.inspect}"
        when 1009
          log_system_notice "received close frame due to too big message sent: status=1009, reason=#{reason.inspect}"
        when 1010
          log_system_notice "received close frame due to extensions negotiation failure: status=1010, reason=#{reason.inspect}"
        else
          log_system_debug "received close frame: status=#{status.inspect}, reason=#{reason.inspect}"  if $oversip_debug
        end

        @connection.client_closed = true
        @connection.close nil, nil
        return false

      when :ping
        log_system_debug "received ping frame: payload_length=#{@payload_length}"  if $oversip_debug
        send_pong_frame @payload

      when :pong
        log_system_debug "received pong frame: payload_length=#{@payload_length}"  if $oversip_debug

      end

      true
    end)
  end # while

end

#send_binary_frame(message) ⇒ Object 



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# File 'lib/oversip/websocket/ws_framing.rb', line 404

def send_binary_frame message
  log_system_debug "sending binary frame: payload_length=#{message.bytesize}"  if $oversip_debug

  frame = "".encode ::Encoding::BINARY

  # byte1 = OPCODE_TO_INT[:binary] | 0b10000000 => 130
  #
  # - FIN bit set.
  # - RSV1-3 bits not set.
  # - opcode = 2
  frame << 130

  length = message.bytesize
  if length <= 125
    frame << length # since rsv4 is 0
  elsif length < 65536 # write 2 byte length
    frame << 126
    frame << [length].pack('n')
  else # write 8 byte length
    frame << 127
    frame << [length >> 32, length & 0xFFFFFFFF].pack("NN")
  end

  if message.encoding == ::Encoding::BINARY
    frame << message
  else
    frame << message.force_encoding(::Encoding::BINARY)
  end

  @connection.send_data frame
  true
end

#send_close_frame(status = nil, reason = nil, in_reply_to_close = nil) ⇒ Object 



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# File 'lib/oversip/websocket/ws_framing.rb', line 502

def send_close_frame status=nil, reason=nil, in_reply_to_close=nil
  @keep_alive_timer.cancel  if @keep_alive_timer

  unless in_reply_to_close
    log_system_debug "sending close frame: status=#{status.inspect}, reason=#{reason.inspect}"  if $oversip_debug
  else
    log_system_debug "sending reply close frame: status=#{status.inspect}, reason=#{reason.inspect}"  if $oversip_debug
  end

  @buffer.clear

  frame = "".encode ::Encoding::BINARY

  # byte1 = OPCODE_TO_INT[:close] | 0b10000000 => 136
  #
  # - FIN bit set.
  # - RSV1-3 bits not set.
  # - opcode = 8
  frame << 136
  if status
    length = ( reason ? 2 + reason.bytesize : 2 )
  else
    length = 0
  end

  frame << length # since rsv4 is 0
  if status
    frame << [status].pack('n')
    if reason
      if reason.encoding == ::Encoding::BINARY
        frame << reason
      else
        frame << reason.force_encoding(::Encoding::BINARY)
      end
    end
  end

  @connection.send_data frame
  true
end

#send_ping_frame(data = nil) ⇒ Object 



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# File 'lib/oversip/websocket/ws_framing.rb', line 438

def send_ping_frame data=nil
  if data
    log_system_debug "sending ping frame: payload_length=#{data.bytesize}"  if $oversip_debug
  else
    log_system_debug "sending ping frame: payload_length=0"  if $oversip_debug
  end

  frame = "".encode ::Encoding::BINARY

  # byte1 = OPCODE_TO_INT[:ping] | 0b10000000 => 137
  #
  # - FIN bit set.
  # - RSV1-3 bits not set.
  # - opcode = 9
  frame << 137

  length = ( data ? data.bytesize : 0 )
  frame << length

  if data
    if data.encoding == ::Encoding::BINARY
      frame << data
    else
      frame << data.force_encoding(::Encoding::BINARY)
    end
  end

  @connection.send_data frame
  true
end

#send_pong_frame(data = nil) ⇒ Object 



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# File 'lib/oversip/websocket/ws_framing.rb', line 470

def send_pong_frame data=nil
  if data
    log_system_debug "sending pong frame: payload_length=#{data.bytesize}"  if $oversip_debug
  else
    log_system_debug "sending pong frame: payload_length=0"  if $oversip_debug
  end

  frame = "".encode ::Encoding::BINARY

  # byte1 = OPCODE_TO_INT[:pong] | 0b10000000 => 138
  #
  # - FIN bit set.
  # - RSV1-3 bits not set.
  # - opcode = 10
  frame << 138

  length = ( data ? data.bytesize : 0 )
  frame << length

  if data
    if data.encoding == ::Encoding::BINARY
      frame << data
    else
      frame << data.force_encoding(::Encoding::BINARY)
    end
  end

  @connection.send_data frame
  true
end

#send_text_frame(message) ⇒ Object

NOTE: A WS message is always set in a single WS frame.



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# File 'lib/oversip/websocket/ws_framing.rb', line 370

def send_text_frame message
  log_system_debug "sending text frame: payload_length=#{message.bytesize}"  if $oversip_debug

  frame = "".encode ::Encoding::BINARY

  # byte1 = OPCODE_TO_INT[:text] | 0b10000000 => 129
  #
  # - FIN bit set.
  # - RSV1-3 bits not set.
  # - opcode = 1
  frame << 129

  length = message.bytesize
  if length <= 125
    frame << length # since rsv4 is 0
  elsif length < 65536 # write 2 byte length
    frame << 126
    frame << [length].pack('n')
  else # write 8 byte length
    frame << 127
    frame << [length >> 32, length & 0xFFFFFFFF].pack("NN")
  end

  if message.encoding == ::Encoding::BINARY
    frame << message
  else
    frame << message.force_encoding(::Encoding::BINARY)
  end

  @connection.send_data frame
  true
end

#text_or_binary_frame? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/oversip/websocket/ws_framing.rb', line 359

def text_or_binary_frame?
  @opcode == 1 or @opcode == 2
end