Module: AVPParser

Included in:
AVP
Defined in:
lib/diameter/avp_parser.rb

Overview

Parser mixin, sharing functionality common to:

* parsing all the AVPs in a message
* parsing the AVPs inside a Grouped AVP

Class Method Summary (collapse)

Class Method Details

+ (true, false) mandatory_bit(flags)

Is the mandatory bit (the second bit) set?

Parameters:

  • flags (String) —

    A string of eight bits, e.g. “00000000”

Returns:

  • (true, false) 


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# File 'lib/diameter/avp_parser.rb', line 20

def self.mandatory_bit(flags)
  flags[1] == '1'
end

+ (Array<AVP>) parse_avps_int(bytes)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns The AVPs parsed out of the bytes.

Parameters:

  • bytes (String) —

    A sequence of bytes representing a set of AVPs.

Returns:

  • (Array<AVP>) —

    The AVPs parsed out of the bytes.



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# File 'lib/diameter/avp_parser.rb', line 28

def self.parse_avps_int(bytes)
  avps = []
  position = 0
  while position < bytes.length
    # Consume the first 8 octets
    first_avp_header = bytes[position..position + 8]
    position += 8

    # Parse them
    code, avp_flags, alength_8, alength_16 = first_avp_header.unpack('NB8Cn')

    length = UInt24.from_u8_and_u16(alength_8, alength_16)

    # Default values in the case where this isn't vendor-specific
    avp_consumed = 8
    avp_vendor = 0

    # If this is vendor-specific, read the vendor ID
    if vendor_id_bit(avp_flags)
      avp_vendor_header = bytes[position..position + 4]
      position += 4
      avp_vendor, = avp_vendor_header.unpack('N')
      avp_consumed = 12
    end

    # Read the content, ensuring it aligns to a 32-byte boundary
    avp_content_length = length - avp_consumed
    avp_content = bytes[position..(position + avp_content_length) - 1]

    padding = 0
    padding += 1 until ((avp_content_length + padding) % 4) == 0

    position += avp_content_length + padding

    # Construct an AVP object from the parsed data
    parsed_avp =
      if vendor_id_bit(avp_flags)
        VendorSpecificAVP.new(code,
                              avp_vendor,
                              mandatory: mandatory_bit(avp_flags),
                              content: avp_content)
      else
        AVP.new(code,
                mandatory: mandatory_bit(avp_flags),
                content: avp_content)
      end
    avps.push parsed_avp
  end
  avps
end

+ (true, false) vendor_id_bit(flags)

Is the vendor-specific bit (the top bit) set?

Parameters:

  • flags (String) —

    A string of eight bits, e.g. “00000000”

Returns:

  • (true, false) 


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# File 'lib/diameter/avp_parser.rb', line 12

def self.vendor_id_bit(flags)
  flags[0] == '1'
end