Class: Mu::Pcap::SCTP::Chunk

Inherits:
Packet
  • Object
show all
Defined in:
lib/mu/pcap/sctp/chunk.rb,
lib/mu/pcap/sctp/chunk/data.rb,
lib/mu/pcap/sctp/chunk/init.rb,
lib/mu/pcap/sctp/chunk/init_ack.rb

Direct Known Subclasses

Data, Init

Defined Under Namespace

Classes: Data, Init, InitAck

Constant Summary

Constants inherited from Packet

Packet::IGNORE_UDP_PORTS

Instance Attribute Summary collapse

Attributes inherited from Packet

#payload, #payload_raw

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Packet

#==, #deepdup, #flow_id, isolate_l7, normalize, #payload_bytes, #to_bytes

Constructor Details

#initialize ⇒ Chunk

Returns a new instance of Chunk.



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# File 'lib/mu/pcap/sctp/chunk.rb', line 12

def initialize
    super
    
    @type  = 0
    @flags = 0
    @size  = 0
end

Instance Attribute Details

#flags ⇒ Object

Returns the value of attribute flags.



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# File 'lib/mu/pcap/sctp/chunk.rb', line 10

def flags
  @flags
end

#size ⇒ Object

Returns the value of attribute size.



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# File 'lib/mu/pcap/sctp/chunk.rb', line 10

def size
  @size
end

#type ⇒ Object

Returns the value of attribute type.



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# File 'lib/mu/pcap/sctp/chunk.rb', line 10

def type
  @type
end

Class Method Details

.dummy_chunk(type, flags, size, bytes) ⇒ Object 



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# File 'lib/mu/pcap/sctp/chunk.rb', line 102

def self.dummy_chunk type, flags, size, bytes
    # Create new dummy chunk
    chunk       = Chunk.new
    chunk.type  = type
    chunk.flags = flags
    chunk.size  = size
    
    # Save the payload
    chunk.payload_raw = chunk.payload = bytes[4..chunk.padded_size]
    
    # Return the result
    return chunk
end

.from_bytes(bytes) ⇒ Object 



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# File 'lib/mu/pcap/sctp/chunk.rb', line 20

def self.from_bytes bytes
    # Basic validation
    Pcap.assert(bytes.length >= 4,
                "Truncated chunk header: 4 > #{bytes.length}")
    
    # Read chunk header
    type, flags, size = bytes.unpack('CCn')
    
    # Validate chunk size
    Pcap.assert(bytes.length >= size,
                "Truncated chunk: #{size} set, #{bytes.length} available")
    
    # Create chunk based on type
    case type
        when CHUNK_DATA
            chunk = Data.from_bytes(flags, size, bytes[4..-1])
        when CHUNK_INIT
            chunk = Init.from_bytes(flags, size, bytes[4..-1])
        when CHUNK_INIT_ACK
            chunk = InitAck.from_bytes(flags, size, bytes[4..-1])
        when CHUNK_SACK
            chunk = dummy_chunk(type, flags, size, bytes)
        when CHUNK_HEARTBEAT
            chunk = dummy_chunk(type, flags, size, bytes)
        when CHUNK_HEARTBEAT_ACK
            chunk = dummy_chunk(type, flags, size, bytes)
        when CHUNK_ABORT
            chunk = dummy_chunk(type, flags, size, bytes)
        when CHUNK_SHUTDOWN
            chunk = dummy_chunk(type, flags, size, bytes)
        when CHUNK_SHUTDOWN_ACK
            chunk = dummy_chunk(type, flags, size, bytes)
        when CHUNK_ERROR
            chunk = dummy_chunk(type, flags, size, bytes)
        when CHUNK_COOKIE_ECHO
            chunk = dummy_chunk(type, flags, size, bytes)
        when CHUNK_COOKIE_ACK
            chunk = dummy_chunk(type, flags, size, bytes)
        when CHUNK_ECNE
            chunk = dummy_chunk(type, flags, size, bytes)
        when CHUNK_CWR
            chunk = dummy_chunk(type, flags, size, bytes)
        when CHUNK_SHUTDOWN_COMPLETE
            chunk = dummy_chunk(type, flags, size, bytes)
        when CHUNK_AUTH
            chunk = dummy_chunk(type, flags, size, bytes)
        when CHUNK_ASCONF_ACK
            chunk = dummy_chunk(type, flags, size, bytes)
        when CHUNK_PADDING
            chunk = dummy_chunk(type, flags, size, bytes)
        when CHUNK_FORWARD_TSN
            chunk = dummy_chunk(type, flags, size, bytes)
        when CHUNK_ASCONF
            chunk = dummy_chunk(type, flags, size, bytes)
        else
            chunk = dummy_chunk(type, flags, size, bytes)
    end
    
    # Return the result
    return chunk
end

Instance Method Details

#padded_size ⇒ Object 



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# File 'lib/mu/pcap/sctp/chunk.rb', line 90

def padded_size
    if 0 == @size % 4
        return @size
    else
        return (@size + 4 - (@size % 4))
    end
end

#to_s ⇒ Object 



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# File 'lib/mu/pcap/sctp/chunk.rb', line 98

def to_s
    return "chunk(%d, %d, %d)" % [@type, @flags, @size]
end

#write(io, ip) ⇒ Object 



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# File 'lib/mu/pcap/sctp/chunk.rb', line 82

def write io, ip
    header = [@type, @flags, @size].pack('CCn')
    
    # Write Chunk header followed by the payload
    io.write(header)
    io.write(@payload_raw)
end