Class: Net::SNMP::PDU

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Includes:
Debug
Defined in:
lib/net/snmp/pdu.rb

Overview

Wrapper around netsnmp_pdu.

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Debug

#debug, #error, #fatal, #info, #print_packet, #time, #warn

Constructor Details

#initialize(pdu_type) ⇒ PDU

Create a new PDU object. pdu_type The type of the PDU. For example, Net::SNMP::SNMP_MSG_GET. See constants.rb



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# File 'lib/net/snmp/pdu.rb', line 12

def initialize(pdu_type)
  @varbinds = []
  case pdu_type
  when FFI::Pointer
    @struct = Wrapper::SnmpPdu.new(pdu_type)
    @command = @struct.command
    v = @struct.variables
    unless v.null?
      @varbinds << Varbind.from_pointer(v)
      while( !(v = v.next_variable).null? )
        @varbinds << Varbind.from_pointer(v)
      end
    end
  when Fixnum
    @struct = Wrapper.snmp_pdu_create(pdu_type)
    @command = pdu_type
  else
    raise Error.new, "invalid pdu type"
  end
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(m, *args) ⇒ Object

Tries to delegate missing methods to the underlying Wrapper::SnmpPdu object. If it does not respond to the method, calls super.



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# File 'lib/net/snmp/pdu.rb', line 125

def method_missing(m, *args)
  if @struct.respond_to?(m)
    @struct.send(m, *args)
  else
    super
  end
end

Instance Attribute Details

#callback ⇒ Object

Returns the value of attribute callback.



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# File 'lib/net/snmp/pdu.rb', line 7

def callback
  @callback
end

#command ⇒ Object

Returns the value of attribute command.



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# File 'lib/net/snmp/pdu.rb', line 7

def command
  @command
end

#struct ⇒ Object

Returns the value of attribute struct.



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# File 'lib/net/snmp/pdu.rb', line 7

def struct
  @struct
end

#varbinds ⇒ Object

Returns the value of attribute varbinds.



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# File 'lib/net/snmp/pdu.rb', line 7

def varbinds
  @varbinds
end

Instance Method Details

#add_varbind(options) ⇒ Object

Adds a variable binding to the pdu. Options:

  • oid The SNMP OID

  • type The data type. Possible values include Net::SNMP::ASN_OCTET_STR, Net::SNMP::ASN_COUNTER, etc. See constants.rb

  • value The value of the varbind. default is nil.



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# File 'lib/net/snmp/pdu.rb', line 138

def add_varbind(options)
  options[:type] ||= case options[:value]
    when String
      Constants::ASN_OCTET_STR
    when Fixnum
      Constants::ASN_INTEGER
    when Net::SNMP::OID
      Constants::ASN_OBJECT_ID
    when nil
      Constants::ASN_NULL
    else
      raise "Unknown value type"
  end

  value = options[:value]
  value_len = case options[:type]
  when Constants::ASN_NULL,
      Constants::SNMP_NOSUCHOBJECT,
      Constants::SNMP_NOSUCHINSTANCE,
      Constants::SNMP_ENDOFMIBVIEW
    0
  else
    options[:value].size
  end

  value = case options[:type]
    when Constants::ASN_INTEGER,
        Constants::ASN_GAUGE,
        Constants::ASN_COUNTER,
        Constants::ASN_TIMETICKS,
        Constants::ASN_UNSIGNED
      new_val = FFI::MemoryPointer.new(:long)
      new_val.write_long(value)
      new_val
    when Constants::ASN_OCTET_STR,
        Constants::ASN_BIT_STR,
        Constants::ASN_OPAQUE
      value
    when Constants::ASN_IPADDRESS
      # TODO

    when Constants::ASN_OBJECT_ID
      value.pointer
    when Constants::ASN_NULL,
        Constants::SNMP_NOSUCHOBJECT,
        Constants::SNMP_NOSUCHINSTANCE,
        Constants::SNMP_ENDOFMIBVIEW
      nil
    else
      if value.respond_to?(:pointer)
        value.pointer
      else
        raise Net::SNMP::Error.new, "Unknown variable type #{options[:type]}"
      end
  end

  oid = options[:oid].kind_of?(OID) ? options[:oid] : OID.new(options[:oid])
  var_ptr = Wrapper.snmp_pdu_add_variable(@struct.pointer, oid.pointer, oid.length_pointer.read_int, options[:type], value, value_len)
  varbind = Varbind.new(var_ptr)
  varbinds << varbind
end

#agent_addr ⇒ Object

The address of the agent that sent this PDU (Valid for SNMPv1 traps only)



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# File 'lib/net/snmp/pdu.rb', line 81

def agent_addr
  # @struct.agent_addr is a binary array of 4 characters,

  # to_a converts this to a ruby array of Integers, then join get's us

  # back to the string form

  @struct.agent_addr.to_a.join('.')
end

#agent_addr=(addr) ⇒ Object

Sets the address of the agent that sent this PDU (Valid for SNMPv1 traps only)



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# File 'lib/net/snmp/pdu.rb', line 73

def agent_addr=(addr)
  # @struct.agent_addr is a binary array of 4 characters,

  # so pack the provided string into four bytes and we can assign it

  @struct.agent_addr = addr.split('.').map{ |octet| octet.to_i }.pack("CCCC")
end

#enterprise ⇒ Object

The enterprise OID of this PDU (Valid for SNMPv1 traps only)



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# File 'lib/net/snmp/pdu.rb', line 67

def enterprise
  OID.from_pointer(@struct.enterprise, @struct.enterprise_length)
end

#enterprise=(oid) ⇒ Object

Sets the enterprise OID of this PDU (Valid for SNMPv1 traps only)



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# File 'lib/net/snmp/pdu.rb', line 57

def enterprise=(oid)
  @i_own_enterprise = true
  oid = OID.new(oid) if oid.kind_of?(String)
  @struct.enterprise = FFI::LibC.calloc(oid.length, OID.oid_size)
  oid.write_to_buffer(@struct.enterprise)
  @struct.enterprise_length = oid.length
end

#error=(value) ⇒ Object Also known as: errstat=, error_status=

Sets the pdu errstat



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# File 'lib/net/snmp/pdu.rb', line 106

def error=(value)
  @struct.errstat = value
end

#error? ⇒ Boolean

Returns true if pdu is in error

Returns:

  • (Boolean) 


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# File 'lib/net/snmp/pdu.rb', line 101

def error?
  self.errstat != 0
end

#error_index=(index) ⇒ Object Also known as: errindex=

Sets the error index



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# File 'lib/net/snmp/pdu.rb', line 113

def error_index=(index)
  @struct.errindex = index
end

#error_message ⇒ Object

A descriptive error message



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# File 'lib/net/snmp/pdu.rb', line 119

def error_message
  Wrapper::snmp_errstring(self.errstat)
end

#free ⇒ Object

Free the pdu Segfaults at the moment - most of the time, anyway. This is troublesome…



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# File 'lib/net/snmp/pdu.rb', line 206

def free
  # HACK

  # snmp_free_pdu segfaults intermittently when freeing the enterprise

  # oid if we've allocated it. Can't figure out why. For now, freeing it manually

  # before calling snmp_free_pdu does the trick

  if @i_own_enterprise
    FFI::LibC.free(@struct.enterprise) unless @struct.enterprise.null?
    @struct.enterprise = FFI::Pointer::NULL
  end
  Wrapper.snmp_free_pdu(@struct.pointer)
end

#max_repetitions ⇒ Object 



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# File 'lib/net/snmp/pdu.rb', line 51

def max_repetitions
  @struct.errindex
end

#max_repetitions=(mr) ⇒ Object

The number of iterations in the table to be read for the repeating objects that follow the non-repeating objects. (For getbulk requests only, max-repititions are stored in errindex location)



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# File 'lib/net/snmp/pdu.rb', line 47

def max_repetitions=(mr)
  @struct.errindex = mr
end

#non_repeaters ⇒ Object

Specifies the number of non-repeating, regular objects at the start of the variable list in the request. (For getbulk requests only, non-repeaters is stored in errstat location)



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# File 'lib/net/snmp/pdu.rb', line 36

def non_repeaters
  @struct.errstat
end

#non_repeaters=(nr) ⇒ Object 



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# File 'lib/net/snmp/pdu.rb', line 40

def non_repeaters=(nr)
  @struct.errstat = nr
end

#print ⇒ Object 



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# File 'lib/net/snmp/pdu.rb', line 218

def print
  puts "PDU"
  if command == Constants::SNMP_MSG_TRAP
      puts " - Enterprise: #{enterprise}"
      puts " - Trap Type: #{trap_type}"
      puts " - Specific Type: #{specific_type}"
      puts " - Agent Addr: #{agent_addr}"
  end

  puts " - Varbinds:"
  varbinds.each do |v|
    puts "   + #{MIB.translate(v.oid.to_s)}(#{v.oid}) = #{v.value}"
  end
end

#print_errors ⇒ Object 



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# File 'lib/net/snmp/pdu.rb', line 199

def print_errors
  puts "errstat = #{self.errstat}, index = #{self.errindex}, message = #{self.error_message}"
end

#uptime ⇒ Object

The uptime for the PDU (Only valid for SNMPv1 traps)



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# File 'lib/net/snmp/pdu.rb', line 90

def uptime
  @struct.time
end

#uptime=(value) ⇒ Object

The uptime for the PDU (Only valid for SNMPv1 traps)



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# File 'lib/net/snmp/pdu.rb', line 96

def uptime=(value)
  @struct.time = value.to_i
end