Class: Net::SNMP::Message

Inherits:
Object
  • Object
show all
Includes:
Debug
Defined in:
lib/net/snmp/message.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Debug

#print_packet, #time

Constructor Details

#initialize(packet) ⇒ Message

Returns a new instance of Message.



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# File 'lib/net/snmp/message.rb', line 31

def initialize(packet)
  @version = nil
  @version_ptr = FFI::MemoryPointer.new(:long, 1)
  @community_ptr = FFI::MemoryPointer.new(:uchar, 100)
  @packet = packet
  @packet_length = packet[0].length
  @type_ptr = FFI::MemoryPointer.new(:int, 1)
  @data_ptr = FFI::MemoryPointer.new(:char, @packet_length)
  @data_ptr.write_bytes(packet[0])
  @cursor_ptr = @data_ptr
  @bytes_remaining_ptr = FFI::MemoryPointer.new(:int, 1)
  @bytes_remaining_ptr.write_bytes([@packet_length].pack("L"))
  @source_address = @packet[1][3]
  @source_port = @packet[1][1]
  #debug "MESSAGE INITIALIZED\n#{self}"
  parse
end

Instance Attribute Details

#community ⇒ Object

Returns the value of attribute community.



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# File 'lib/net/snmp/message.rb', line 10

def community
  @community
end

#community_ptr ⇒ Object

Returns the value of attribute community_ptr.



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# File 'lib/net/snmp/message.rb', line 10

def community_ptr
  @community_ptr
end

#pdu ⇒ Object

Returns the value of attribute pdu.



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# File 'lib/net/snmp/message.rb', line 10

def pdu
  @pdu
end

#source_address ⇒ Object

Returns the value of attribute source_address.



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# File 'lib/net/snmp/message.rb', line 10

def source_address
  @source_address
end

#source_port ⇒ Object

Returns the value of attribute source_port.



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# File 'lib/net/snmp/message.rb', line 10

def source_port
  @source_port
end

#version ⇒ Object

Returns the value of attribute version.



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# File 'lib/net/snmp/message.rb', line 10

def version
  @version
end

#version_ptr ⇒ Object

Returns the value of attribute version_ptr.



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# File 'lib/net/snmp/message.rb', line 10

def version_ptr
  @version_ptr
end

Class Method Details

.parse(packet) ⇒ Object 



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# File 'lib/net/snmp/message.rb', line 6

def self.parse(packet)
  Message.new(packet)
end

Instance Method Details

#echo ⇒ Object

Sends a response PDU to the source of the message with all of the same varbinds. (Useful for sets & informs, where this is how you indicate success)



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# File 'lib/net/snmp/message.rb', line 60

def echo
  response_pdu = make_response_pdu
  pdu.varbinds.each do |vb|
    response_pdu.add_varbind(oid: vb.oid, type: vb.type, value: vb.value)
  end
  respond(response_pdu)
end

#make_response_pdu ⇒ Object

Constructs a PDU for responding to this message. This makes sure the PDU has the right request ID, version, and community set.



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# File 'lib/net/snmp/message.rb', line 71

def make_response_pdu
  response_pdu = PDU.new(Constants::SNMP_MSG_RESPONSE)
  response_pdu.reqid = pdu.reqid
  response_pdu.version = version
  response_pdu.community = pdu.community
  response_pdu
end

#respond(response_pdu) ⇒ Object

Sends the given PDU back to the origin of this message. The origin is the same address and port that the message was received from.



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# File 'lib/net/snmp/message.rb', line 52

def respond(response_pdu)
  Session.open(peername: source_address, port: source_port, version: version_name) do |sess|
    sess.send_pdu(response_pdu)
  end
end

#version_name ⇒ Object 



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# File 'lib/net/snmp/message.rb', line 18

def version_name
  case @version
  when Constants::SNMP_VERSION_1
    '1'
  when Constants::SNMP_VERSION_2c
    '2c'
  when Constants::SNMP_VERSION_3
    '3'
  else
    raise "Invalid SNMP version: #{@version}"
  end
end