Module: Diameter::Internals::AVPParser

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

.mandatory_bit(flags) ⇒ true, false

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 22

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

.parse_avp_header(bytes) ⇒ Array(Fixnum, Fixnum, Bool, Fixnum, Fixnum)

(8 or 12), AVP code, mandatory bit, length and vendor-ID (or 0 in the case of a non-vendor-specific AVP).

Returns:

  • (Array(Fixnum, Fixnum, Bool, Fixnum, Fixnum)) —

    The bytes consumed



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# File 'lib/diameter/avp_parser.rb', line 30

def self.parse_avp_header(bytes)
  first_avp_header = bytes[0..8]
  # Parse them
  code, avp_flags, alength_8, alength_16 =
    first_avp_header.unpack('NB8Cn')
  
  mandatory = mandatory_bit(avp_flags)
  length = UInt24.from_u8_and_u16(alength_8, alength_16)

  if vendor_id_bit(avp_flags)
    avp_vendor_header = bytes[8..12]
    avp_vendor, = avp_vendor_header.unpack('N')
    [12, code, mandatory, length, avp_vendor]
  else
    [8, code, mandatory, length, 0]
  end
end

.parse_avps_int(bytes) ⇒ Array<AVP>

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 52

def self.parse_avps_int(bytes)
  avps = []
  position = 0
  while position < bytes.length
    # Consume the first 8 octets
    avp_consumed, code, mandatory, length, avp_vendor = parse_avp_header(bytes[position..-1])
    position += avp_consumed

    # 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 = AVP.new(code,
                         vendor_id: avp_vendor,
                         mandatory: mandatory,
                         content: avp_content)

    avps.push parsed_avp
  end
  avps
end

.vendor_id_bit(flags) ⇒ true, false

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 14

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