Class: PacketGen::Header::SNMP

Inherits:
ASN1Base
  • Object
show all
Defined in:
lib/packetgen/header/snmp.rb

Overview

Simple Network Management Protocol (SNMP)

See github.com/lemontree55/packetgen/wiki/SNMP

SNMP is defined from ASN.1:

Message ::=
  SEQUENCE {
       version
          INTEGER {
              version-1(0)
          },
       community      -- community name
           OCTET STRING,
       data           -- e.g., PDUs if trivial
           ANY        -- authentication is being used
  }

It has 3 attributes, accessible through #[]:

  • :version, SNMP protocol version (type RASN1::Types::Integer with enumeration),

  • :community (type RASN1::Types::OctetString),

  • :data (type PDUs).

Examples:

snmp = PacketGen::Header::SNMP.new(version: "v3",
                                   chosen_pdu: PacketGen::Header::SNMP::PDU_SET,
                                   pdu: { id: 1, varbindlist: [{ name: '1.2.3.4' }] })
snmp.version        #=> "v3"
snmp.community      #=> "public"
snmp.pdu.class      #=> PacketGen::Header::SNMP::SetRequest
snmp.pdu[:id].value #=> 1
snmp.pdu[:varbindlist][0][:name].inspect #=> 'name OBJECT ID: "1.2.3.4"'
snmp.pdu[:varbindlist][0][:name].value   #=> "1.2.3.4"

Author:

  • Sylvain Daubert

  • LemonTree55

Since:

  • 2.0.0

Defined Under Namespace

Classes: Bulk, GetNextRequest, GetRequest, GetResponse, InformRequest, PDUs, Report, SetRequest, Trapv1, Trapv2, VarBind, VariableBindings

Constant Summary collapse

UDP_PORT1 =

Agents listen to this port

Since:

  • 2.0.0

161
UDP_PORT2 =

Configuration sinks listen to this port

Since:

  • 2.0.0

162
PDU_GET =

Implicit tag number for GetRequest PDU type

Since:

  • 2.0.0

0
PDU_NEXT =

Implicit tag number for GetNextRequest PDU type

Since:

  • 2.0.0

1
PDU_RESPONSE =

Implicit tag number for GetResponse PDU type

Since:

  • 2.0.0

2
PDU_SET =

Implicit tag number for SetRequest PDU type

Since:

  • 2.0.0

3
PDU_TRAPv1 =

Implicit tag number for Trapv1 PDU type

Since:

  • 2.0.0

4
PDU_BULK =

Implicit tag number for Bulk PDU type

Since:

  • 2.0.0

5
PDU_INFORM =

Implicit tag number for InformRequest PDU type

Since:

  • 2.0.0

6
PDU_TRAPv2 =

Implicit tag number for Trapv2 PDU type

Since:

  • 2.0.0

7
PDU_REPORT =

Implicit tag number for Report PDU type

Since:

  • 2.0.0

8
ERRORS =

Error types

Since:

  • 2.0.0

{
  'no_error' => 0,
  'too_big' => 1,
  'no_such_name' => 2,
  'bad_value' => 3,
  'read_only' => 4,
  'generic_error' => 5,
  'no_access' => 6,
  'wrong_type' => 7,
  'wrong_length' => 8,
  'wrong_encoding' => 9,
  'wrong_value' => 10,
  'no_creation' => 11,
  'inconsistent_value' => 12,
  'ressource_unavailable' => 13,
  'commit_failed' => 14,
  'undo_failed' => 15,
  'authorization_error' => 16,
  'not_writable' => 17,
  'inconsistent_name' => 18
}.freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from ASN1Base

define_attributes, known_headers, #read

Methods included from PacketGen::Headerable

included, #method_name, #packet, #packet=, #parse?, #protocol_name, #read, #to_s

Constructor Details

#initialize(options = {}) ⇒ SNMP

Returns a new instance of SNMP.

Parameters:

  • options (Hash) (defaults to: {})

Options Hash (options):

  • :version (Integer, String)
  • :community (String)
  • :chosen_pdu (Integer) —

    Set PDU type

  • :pdu (Hash) —

    Set PDU content

Since:

  • 2.0.0


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# File 'lib/packetgen/header/snmp.rb', line 378

def initialize(options={})
  super
  data.chosen = options[:chosen_pdu] if options[:chosen_pdu]
  return unless options[:pdu]

  klass = data.root.chosen_value.class
  data.root.value[data.chosen] = klass.new(options[:pdu])
end

Instance Attribute Details

#community ⇒ String

community attribute. Shortcut for snmp[:community].value.

Returns:

  • (String) 

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# File 'lib/packetgen/header/snmp.rb', line 57

class SNMP < ASN1Base
  # Agents listen to this port
  UDP_PORT1 = 161
  # Configuration sinks listen to this port
  UDP_PORT2 = 162

  # Implicit tag number for GetRequest PDU type
  PDU_GET      = 0
  # Implicit tag number for GetNextRequest PDU type
  PDU_NEXT     = 1
  # Implicit tag number for GetResponse PDU type
  PDU_RESPONSE = 2
  # Implicit tag number for SetRequest PDU type
  PDU_SET      = 3
  # Implicit tag number for Trapv1 PDU type
  PDU_TRAPv1   = 4
  # Implicit tag number for Bulk PDU type
  PDU_BULK     = 5
  # Implicit tag number for InformRequest PDU type
  PDU_INFORM   = 6
  # Implicit tag number for Trapv2 PDU type
  PDU_TRAPv2   = 7
  # Implicit tag number for Report PDU type
  PDU_REPORT   = 8

  # Error types
  ERRORS = {
    'no_error' => 0,
    'too_big' => 1,
    'no_such_name' => 2,
    'bad_value' => 3,
    'read_only' => 4,
    'generic_error' => 5,
    'no_access' => 6,
    'wrong_type' => 7,
    'wrong_length' => 8,
    'wrong_encoding' => 9,
    'wrong_value' => 10,
    'no_creation' => 11,
    'inconsistent_value' => 12,
    'ressource_unavailable' => 13,
    'commit_failed' => 14,
    'undo_failed' => 15,
    'authorization_error' => 16,
    'not_writable' => 17,
    'inconsistent_name' => 18
  }.freeze

  # Class to handle SNMP VarBind
  #  VarBind ::= SEQUENCE {
  #                name  OBJECT IDENTIFIER,
  #                value ANY     -- depends on name
  #              }
  # This class associates a +:name+ (type +RASN1::Types::ObjectId+) to a +:value+ (any RASN1 type).
  # @example
  #   vb = PacketGen::Header::SNMP::VarBind.new(name: "1.2.3.4", value: RASN1::Types::OctetString.new(value: "abc"))
  #   vb[:name].class  # => RASN1::Types::ObjectId
  #   vb[:name].value  # => "1.2.3.4"
  # @author Sylvain Daubert
  # @author LemonTree55
  class VarBind < RASN1::Model
    sequence :varbind,
             content: [objectid(:name),
                       any(:value)]
  end

  # Class to handle SNMP VariableBindingsList
  #  VarBindList ::= SEQUENCE (SIZE (0..max-bindings)) OF VarBind
  # This is a sequence of {VarBind}.
  # @example
  #  bindings = PacketGen::Header::SNMP::VariableBindings.new
  #  bindings << { name: "1.2.3.4", value: RASN1::Types::OctetString.new(value: "abc") }
  # @author Sylvain Daubert
  # @author LemonTree55
  class VariableBindings < RASN1::Model
    sequence_of :bindings, VarBind

    # Get 'idx'th element from the list
    # @return [VarBind,nil]
    def [](idx)
      value[idx]
    end

    # Get element counts in list
    # @return [Integer]
    def size
      value.size
    end
  end

  # Class to handle GetRequest PDU
  #  GetRequest-PDU ::= [0] IMPLICIT PDU
  #
  #  PDU ::= SEQUENCE {
  #              request-id INTEGER (-214783648..214783647),
  #
  #              error-status                -- sometimes ignored
  #                  INTEGER {
  #                      noError(0),
  #                      tooBig(1),
  #                      noSuchName(2),      -- for proxy compatibility
  #                      badValue(3),        -- for proxy compatibility
  #                      readOnly(4),        -- for proxy compatibility
  #                      genErr(5),
  #                      noAccess(6),
  #                      wrongType(7),
  #                      wrongLength(8),
  #                      wrongEncoding(9),
  #                      wrongValue(10),
  #                      noCreation(11),
  #                      inconsistentValue(12),
  #                      resourceUnavailable(13),
  #                      commitFailed(14),
  #                      undoFailed(15),
  #                      authorizationError(16),
  #                      notWritable(17),
  #                      inconsistentName(18)
  #                  },
  #
  #              error-index                 -- sometimes ignored
  #                  INTEGER (0..max-bindings),
  #
  #              variable-bindings           -- values are sometimes ignored
  #                  VarBindList
  #          }
  # This class defines a GetRequest SNMP PDU. It defines 4 attributes:
  # * an +:id+ (request-id, type +RASN1::Types::Integer+),
  # * an +:error+ (error-status, type +RASN1::Types::Integer with enumeration definition from {ERRORS}),
  # * an +:error_index+ (type +RASN1::Types::Integer+),
  # * a +:barbindlist+ (variable-bindings, type {VariableBindings}).
  #
  # @example
  #   req = PacketGen::Header::SNMP::GetRequest.new(id: 1, error: "no_error")
  #   req[:id].value    #=> 1
  #   req[:error].value #=> "no_error"
  #   req[:error].to_i  #=> 0
  #   req[:varbindlist] << { name: "1.2.3.4", value: RASN1::Types::OctetString.new(value: "abcd") }
  # @author Sylvain Daubert
  # @author LemonTree55
  class GetRequest < RASN1::Model
    sequence :pdu,
             implicit: SNMP::PDU_GET, constructed: true,
             content: [integer(:id, value: 0),
                       integer(:error, value: 0, enum: ERRORS),
                       integer(:error_index, value: 0),
                       model(:varbindlist, VariableBindings)]

    def initialize(args={})
      super
    end
  end

  # Class to handle GetNextRequest PDU
  #  GetNextRequest-PDU ::= [1] IMPLICIT PDU   -- PDU definition: see GetRequest
  # @see GetRequest
  # @author Sylvain Daubert
  class GetNextRequest < GetRequest
    root_options implicit: SNMP::PDU_NEXT
  end

  # Class to handle GetResponse PDU
  #  GetResponse-PDU ::= [2] IMPLICIT PDU   -- PDU definition: see GetRequest
  # @see GetRequest
  # @author Sylvain Daubert
  class GetResponse < GetRequest
    root_options implicit: SNMP::PDU_RESPONSE
  end

  # Class to handle SetRequest PDU
  #  SetRequest-PDU ::= [3] IMPLICIT PDU   -- PDU definition: see GetRequest
  # @see GetRequest
  # @author Sylvain Daubert
  class SetRequest < GetRequest
    root_options implicit: SNMP::PDU_SET
  end

  # Class to handle Trap from SNMPv1
  #  Trap-PDU ::= [4] IMPLICIT SEQUENCE {
  #                          enterprise OBJECT IDENTIFIER,
  #                          agent-addr NetworkAddress,
  #                          generic-trap      -- generic trap type
  #                              INTEGER {
  #                                  coldStart(0),
  #                                  warmStart(1),
  #                                  linkDown(2),
  #                                  linkUp(3),
  #                                  authenticationFailure(4),
  #                                  egpNeighborLoss(5),
  #                                  enterpriseSpecific(6)
  #                              },
  #                          specific-trap INTEGER,
  #                          time-stamp TimeTicks,
  #                          variable-bindings VarBindList
  #                   }
  # This class defines 6 attributes accessibles through +#[]+:
  # * +:enterprise+ for request-id (type +RASN1::Types::ObjectId+),
  # * +:agent_addr+ (type +RASN1::Types::Integer+),
  # * +:generic_trap+ (type +RASN1::Types::Integer+),
  # * +:specific_trap+ (type +RASN1::Types::Integer+),
  # * +:timestamp+ (type +RASN1::Types::Integer+),
  # * +:varbindlist+ for variable-bindings (type {VariableBindings}).
  # @author Sylvain Daubert
  # @author LemonTree55
  class Trapv1 < RASN1::Model
    sequence :trap,
             implicit: SNMP::PDU_TRAPv1, constructed: true,
             content: [objectid(:enterprise),
                       octet_string(:agent_addr),
                       integer(:generic_trap, enum: { 'cold_start' => 0,
                                                      'warm_start' => 1,
                                                      'link_down' => 2,
                                                      'link_up' => 3,
                                                      'auth_failure' => 4,
                                                      'egp_neighbor_loss' => 5,
                                                      'specific' => 6 }),
                       integer(:specific_trap),
                       integer(:timestamp),
                       model(:varbindlist, VariableBindings)]
  end

  # Class to handle Bulk PDU
  #  GetBulkRequest-PDU ::= [5] IMPLICIT BulkPDU
  #
  #  BulkPDU ::=                         -- must be identical in
  #        SEQUENCE {                    -- structure to PDU
  #            request-id      INTEGER (-214783648..214783647),
  #            non-repeaters   INTEGER (0..max-bindings),
  #            max-repetitions INTEGER (0..max-bindings),
  #            variable-bindings           -- values are ignored
  #                VarBindList
  #        }
  #
  # This class defines 4 values accessibles through +#[]+:
  # * +:id+ for request-id (type +RASN1::Types::Integer+),
  # * +:non_repeaters+ (type +RASN1::Types::Integer+),
  # * +:max_repetitions+ (type +RASN1::Types::Integer+),
  # * +varbindlist+ for variable-bindings (type {VariableBindings}).
  # @example
  #   bulk = PacketGen::Header::SNMP::Bulk.new(id: 1, non_repeaters: 2, max_repetitions: 2)
  #   bulk[:varbindlist] << { name: '1.2.3.4', value: RASN1::Types::OctetString.new(value: "abcd") }
  #   bulk[:id].inspect  # => "id INTEGER: 1"
  #   bulk[:id].value    # => 1
  #   bulk[:varbindlist][0][:name].value  # => "1.2.3.4"
  # @author Sylvain Daubert
  # @author LemonTree55
  class Bulk < RASN1::Model
    sequence :bulkpdu,
             implicit: SNMP::PDU_BULK, constructed: true,
             content: [integer(:id, value: 0),
                       integer(:non_repeaters),
                       integer(:max_repetitions),
                       model(:varbindlist, VariableBindings)]
  end

  # Class to handle InformRequest PDU
  #  InformRequest-PDU ::= [6] IMPLICIT PDU   -- PDU definition: see GetRequest
  # @see GetRequest
  # @author Sylvain Daubert
  class InformRequest < GetRequest
    root_options implicit: SNMP::PDU_INFORM
  end

  # Class to handle Trapv2 PDU
  #  SNMPv2-Trap-PDU ::= [7] IMPLICIT PDU   -- PDU definition: see GetRequest
  # @see GetRequest
  # @author Sylvain Daubert
  class Trapv2 < GetRequest
    root_options implicit: SNMP::PDU_TRAPv2
  end

  # Class to handle Report PDU
  #  Report-PDU ::= [8] IMPLICIT PDU   -- PDU definition: see GetRequest
  # @see GetRequest
  # @author Sylvain Daubert
  class Report < GetRequest
    root_options implicit: SNMP::PDU_REPORT
  end

  # Class to handle PDUs from SNMP packet
  #  PDUs ::= CHOICE {
  #             get-request      [0] IMPLICIT PDU,
  #             get-next-request [1] IMPLICIT PDU,
  #             get-response     [2] IMPLICIT PDU,
  #             set-request      [3] IMPLICIT PDU,
  #             snmpV1-trap      [4] IMPLICIT PDU,
  #             get-bulk-request [5] IMPLICIT PDU,
  #             inform-request   [6] IMPLICIT PDU,
  #             snmpV2-trap      [7] IMPLICIT PDU,
  #             report           [8] IMPLICIT PDU
  #           }
  # This class is a wrapper. It contains one of {GetRequest}, {GetNextRequest}, {GetResponse}, {SetRequest},
  # {Trapv1}, {Bulk}, {InformRequest}, {Trapv2} or {Report}.
  # @author Sylvain Daubert
  # @author LemonTree55
  class PDUs < RASN1::Model
    choice :pdus,
           content: [model(:get_request, GetRequest),
                     model(:get_next_request, GetNextRequest),
                     model(:get_response, GetResponse),
                     model(:set_request, SetRequest),
                     model(:trapv1, Trapv1),
                     model(:bulk, Bulk),
                     model(:inform, InformRequest),
                     model(:trapv2, Trapv2),
                     model(:report, Report)]
  end

  sequence :message,
           content: [integer(:version,
                             value: 'v2c',
                             enum: { 'v1' => 0, 'v2c' => 1, 'v2' => 2, 'v3' => 3 }),
                     octet_string(:community, value: 'public'),
                     model(:data, PDUs)]

  define_attributes :version, :community

  # @param [Hash] options
  # @option options [Integer,String] :version
  # @option options [String] :community
  # @option options [Integer] :chosen_pdu Set PDU type
  # @option options [Hash] :pdu Set PDU content
  def initialize(options={})
    super
    data.chosen = options[:chosen_pdu] if options[:chosen_pdu]
    return unless options[:pdu]

    klass = data.root.chosen_value.class
    data.root.value[data.chosen] = klass.new(options[:pdu])
  end

  # accessor to data payload. Shortcut for +snmp[:data]+.
  # @return [ASN1::Types::Choice]
  def data
    @elements[:data]
  end

  # shortcut to PDU (+snmp[:data].chosen_value+).
  # @return [GetRequest, Bulk, Trapv1, nil] return `nil` if no CHOICE was done
  def pdu
    if data.chosen.nil?
      nil
    else
      data.root.chosen_value
    end
  end

  # Inspect SNMP header
  # @return [String]
  def inspect
    str = super
    str << Inspect.shift_level
    str << if self[:data].chosen.nil?
             Inspect::FMT_ATTR % [self[:data].type, :data, '']
           else
             inspect_data
           end
  end

  # @api private
  # @note This method is used internally by PacketGen and should not be
  #       directly called
  # @param [Packet] packet
  # @return [void]
  # @since 2.7.0 Set UDP sport according to bindings, only if sport is not set yet (i.e. is zero).
  #  Needed by new bind API.
  def added_to_packet(packet)
    return unless packet.is?('UDP')
    return unless packet.udp.sport.zero?

    packet.udp.sport = packet.udp.dport
  end

  private

  def inspect_data
    data = self[:data]
    str = Inspect::FMT_ATTR % [data.type, :data, data.chosen_value.type]
    str << Inspect.dashed_line('ASN.1 content')
    str << data.chosen_value.inspect(1)
    begin
      str << Inspect.inspect_body(self[:message].to_der, 'ASN.1 DER')
    rescue StandardError => e
      raise unless e.message.match?(/TAG.*not handled/)
    end
    str
  end
end

#version ⇒ String

version attribute. Shortcut for snmp[:version].value. String values are: v1, v2, v2c and v3.

Returns:

  • (String) 

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# File 'lib/packetgen/header/snmp.rb', line 57

class SNMP < ASN1Base
  # Agents listen to this port
  UDP_PORT1 = 161
  # Configuration sinks listen to this port
  UDP_PORT2 = 162

  # Implicit tag number for GetRequest PDU type
  PDU_GET      = 0
  # Implicit tag number for GetNextRequest PDU type
  PDU_NEXT     = 1
  # Implicit tag number for GetResponse PDU type
  PDU_RESPONSE = 2
  # Implicit tag number for SetRequest PDU type
  PDU_SET      = 3
  # Implicit tag number for Trapv1 PDU type
  PDU_TRAPv1   = 4
  # Implicit tag number for Bulk PDU type
  PDU_BULK     = 5
  # Implicit tag number for InformRequest PDU type
  PDU_INFORM   = 6
  # Implicit tag number for Trapv2 PDU type
  PDU_TRAPv2   = 7
  # Implicit tag number for Report PDU type
  PDU_REPORT   = 8

  # Error types
  ERRORS = {
    'no_error' => 0,
    'too_big' => 1,
    'no_such_name' => 2,
    'bad_value' => 3,
    'read_only' => 4,
    'generic_error' => 5,
    'no_access' => 6,
    'wrong_type' => 7,
    'wrong_length' => 8,
    'wrong_encoding' => 9,
    'wrong_value' => 10,
    'no_creation' => 11,
    'inconsistent_value' => 12,
    'ressource_unavailable' => 13,
    'commit_failed' => 14,
    'undo_failed' => 15,
    'authorization_error' => 16,
    'not_writable' => 17,
    'inconsistent_name' => 18
  }.freeze

  # Class to handle SNMP VarBind
  #  VarBind ::= SEQUENCE {
  #                name  OBJECT IDENTIFIER,
  #                value ANY     -- depends on name
  #              }
  # This class associates a +:name+ (type +RASN1::Types::ObjectId+) to a +:value+ (any RASN1 type).
  # @example
  #   vb = PacketGen::Header::SNMP::VarBind.new(name: "1.2.3.4", value: RASN1::Types::OctetString.new(value: "abc"))
  #   vb[:name].class  # => RASN1::Types::ObjectId
  #   vb[:name].value  # => "1.2.3.4"
  # @author Sylvain Daubert
  # @author LemonTree55
  class VarBind < RASN1::Model
    sequence :varbind,
             content: [objectid(:name),
                       any(:value)]
  end

  # Class to handle SNMP VariableBindingsList
  #  VarBindList ::= SEQUENCE (SIZE (0..max-bindings)) OF VarBind
  # This is a sequence of {VarBind}.
  # @example
  #  bindings = PacketGen::Header::SNMP::VariableBindings.new
  #  bindings << { name: "1.2.3.4", value: RASN1::Types::OctetString.new(value: "abc") }
  # @author Sylvain Daubert
  # @author LemonTree55
  class VariableBindings < RASN1::Model
    sequence_of :bindings, VarBind

    # Get 'idx'th element from the list
    # @return [VarBind,nil]
    def [](idx)
      value[idx]
    end

    # Get element counts in list
    # @return [Integer]
    def size
      value.size
    end
  end

  # Class to handle GetRequest PDU
  #  GetRequest-PDU ::= [0] IMPLICIT PDU
  #
  #  PDU ::= SEQUENCE {
  #              request-id INTEGER (-214783648..214783647),
  #
  #              error-status                -- sometimes ignored
  #                  INTEGER {
  #                      noError(0),
  #                      tooBig(1),
  #                      noSuchName(2),      -- for proxy compatibility
  #                      badValue(3),        -- for proxy compatibility
  #                      readOnly(4),        -- for proxy compatibility
  #                      genErr(5),
  #                      noAccess(6),
  #                      wrongType(7),
  #                      wrongLength(8),
  #                      wrongEncoding(9),
  #                      wrongValue(10),
  #                      noCreation(11),
  #                      inconsistentValue(12),
  #                      resourceUnavailable(13),
  #                      commitFailed(14),
  #                      undoFailed(15),
  #                      authorizationError(16),
  #                      notWritable(17),
  #                      inconsistentName(18)
  #                  },
  #
  #              error-index                 -- sometimes ignored
  #                  INTEGER (0..max-bindings),
  #
  #              variable-bindings           -- values are sometimes ignored
  #                  VarBindList
  #          }
  # This class defines a GetRequest SNMP PDU. It defines 4 attributes:
  # * an +:id+ (request-id, type +RASN1::Types::Integer+),
  # * an +:error+ (error-status, type +RASN1::Types::Integer with enumeration definition from {ERRORS}),
  # * an +:error_index+ (type +RASN1::Types::Integer+),
  # * a +:barbindlist+ (variable-bindings, type {VariableBindings}).
  #
  # @example
  #   req = PacketGen::Header::SNMP::GetRequest.new(id: 1, error: "no_error")
  #   req[:id].value    #=> 1
  #   req[:error].value #=> "no_error"
  #   req[:error].to_i  #=> 0
  #   req[:varbindlist] << { name: "1.2.3.4", value: RASN1::Types::OctetString.new(value: "abcd") }
  # @author Sylvain Daubert
  # @author LemonTree55
  class GetRequest < RASN1::Model
    sequence :pdu,
             implicit: SNMP::PDU_GET, constructed: true,
             content: [integer(:id, value: 0),
                       integer(:error, value: 0, enum: ERRORS),
                       integer(:error_index, value: 0),
                       model(:varbindlist, VariableBindings)]

    def initialize(args={})
      super
    end
  end

  # Class to handle GetNextRequest PDU
  #  GetNextRequest-PDU ::= [1] IMPLICIT PDU   -- PDU definition: see GetRequest
  # @see GetRequest
  # @author Sylvain Daubert
  class GetNextRequest < GetRequest
    root_options implicit: SNMP::PDU_NEXT
  end

  # Class to handle GetResponse PDU
  #  GetResponse-PDU ::= [2] IMPLICIT PDU   -- PDU definition: see GetRequest
  # @see GetRequest
  # @author Sylvain Daubert
  class GetResponse < GetRequest
    root_options implicit: SNMP::PDU_RESPONSE
  end

  # Class to handle SetRequest PDU
  #  SetRequest-PDU ::= [3] IMPLICIT PDU   -- PDU definition: see GetRequest
  # @see GetRequest
  # @author Sylvain Daubert
  class SetRequest < GetRequest
    root_options implicit: SNMP::PDU_SET
  end

  # Class to handle Trap from SNMPv1
  #  Trap-PDU ::= [4] IMPLICIT SEQUENCE {
  #                          enterprise OBJECT IDENTIFIER,
  #                          agent-addr NetworkAddress,
  #                          generic-trap      -- generic trap type
  #                              INTEGER {
  #                                  coldStart(0),
  #                                  warmStart(1),
  #                                  linkDown(2),
  #                                  linkUp(3),
  #                                  authenticationFailure(4),
  #                                  egpNeighborLoss(5),
  #                                  enterpriseSpecific(6)
  #                              },
  #                          specific-trap INTEGER,
  #                          time-stamp TimeTicks,
  #                          variable-bindings VarBindList
  #                   }
  # This class defines 6 attributes accessibles through +#[]+:
  # * +:enterprise+ for request-id (type +RASN1::Types::ObjectId+),
  # * +:agent_addr+ (type +RASN1::Types::Integer+),
  # * +:generic_trap+ (type +RASN1::Types::Integer+),
  # * +:specific_trap+ (type +RASN1::Types::Integer+),
  # * +:timestamp+ (type +RASN1::Types::Integer+),
  # * +:varbindlist+ for variable-bindings (type {VariableBindings}).
  # @author Sylvain Daubert
  # @author LemonTree55
  class Trapv1 < RASN1::Model
    sequence :trap,
             implicit: SNMP::PDU_TRAPv1, constructed: true,
             content: [objectid(:enterprise),
                       octet_string(:agent_addr),
                       integer(:generic_trap, enum: { 'cold_start' => 0,
                                                      'warm_start' => 1,
                                                      'link_down' => 2,
                                                      'link_up' => 3,
                                                      'auth_failure' => 4,
                                                      'egp_neighbor_loss' => 5,
                                                      'specific' => 6 }),
                       integer(:specific_trap),
                       integer(:timestamp),
                       model(:varbindlist, VariableBindings)]
  end

  # Class to handle Bulk PDU
  #  GetBulkRequest-PDU ::= [5] IMPLICIT BulkPDU
  #
  #  BulkPDU ::=                         -- must be identical in
  #        SEQUENCE {                    -- structure to PDU
  #            request-id      INTEGER (-214783648..214783647),
  #            non-repeaters   INTEGER (0..max-bindings),
  #            max-repetitions INTEGER (0..max-bindings),
  #            variable-bindings           -- values are ignored
  #                VarBindList
  #        }
  #
  # This class defines 4 values accessibles through +#[]+:
  # * +:id+ for request-id (type +RASN1::Types::Integer+),
  # * +:non_repeaters+ (type +RASN1::Types::Integer+),
  # * +:max_repetitions+ (type +RASN1::Types::Integer+),
  # * +varbindlist+ for variable-bindings (type {VariableBindings}).
  # @example
  #   bulk = PacketGen::Header::SNMP::Bulk.new(id: 1, non_repeaters: 2, max_repetitions: 2)
  #   bulk[:varbindlist] << { name: '1.2.3.4', value: RASN1::Types::OctetString.new(value: "abcd") }
  #   bulk[:id].inspect  # => "id INTEGER: 1"
  #   bulk[:id].value    # => 1
  #   bulk[:varbindlist][0][:name].value  # => "1.2.3.4"
  # @author Sylvain Daubert
  # @author LemonTree55
  class Bulk < RASN1::Model
    sequence :bulkpdu,
             implicit: SNMP::PDU_BULK, constructed: true,
             content: [integer(:id, value: 0),
                       integer(:non_repeaters),
                       integer(:max_repetitions),
                       model(:varbindlist, VariableBindings)]
  end

  # Class to handle InformRequest PDU
  #  InformRequest-PDU ::= [6] IMPLICIT PDU   -- PDU definition: see GetRequest
  # @see GetRequest
  # @author Sylvain Daubert
  class InformRequest < GetRequest
    root_options implicit: SNMP::PDU_INFORM
  end

  # Class to handle Trapv2 PDU
  #  SNMPv2-Trap-PDU ::= [7] IMPLICIT PDU   -- PDU definition: see GetRequest
  # @see GetRequest
  # @author Sylvain Daubert
  class Trapv2 < GetRequest
    root_options implicit: SNMP::PDU_TRAPv2
  end

  # Class to handle Report PDU
  #  Report-PDU ::= [8] IMPLICIT PDU   -- PDU definition: see GetRequest
  # @see GetRequest
  # @author Sylvain Daubert
  class Report < GetRequest
    root_options implicit: SNMP::PDU_REPORT
  end

  # Class to handle PDUs from SNMP packet
  #  PDUs ::= CHOICE {
  #             get-request      [0] IMPLICIT PDU,
  #             get-next-request [1] IMPLICIT PDU,
  #             get-response     [2] IMPLICIT PDU,
  #             set-request      [3] IMPLICIT PDU,
  #             snmpV1-trap      [4] IMPLICIT PDU,
  #             get-bulk-request [5] IMPLICIT PDU,
  #             inform-request   [6] IMPLICIT PDU,
  #             snmpV2-trap      [7] IMPLICIT PDU,
  #             report           [8] IMPLICIT PDU
  #           }
  # This class is a wrapper. It contains one of {GetRequest}, {GetNextRequest}, {GetResponse}, {SetRequest},
  # {Trapv1}, {Bulk}, {InformRequest}, {Trapv2} or {Report}.
  # @author Sylvain Daubert
  # @author LemonTree55
  class PDUs < RASN1::Model
    choice :pdus,
           content: [model(:get_request, GetRequest),
                     model(:get_next_request, GetNextRequest),
                     model(:get_response, GetResponse),
                     model(:set_request, SetRequest),
                     model(:trapv1, Trapv1),
                     model(:bulk, Bulk),
                     model(:inform, InformRequest),
                     model(:trapv2, Trapv2),
                     model(:report, Report)]
  end

  sequence :message,
           content: [integer(:version,
                             value: 'v2c',
                             enum: { 'v1' => 0, 'v2c' => 1, 'v2' => 2, 'v3' => 3 }),
                     octet_string(:community, value: 'public'),
                     model(:data, PDUs)]

  define_attributes :version, :community

  # @param [Hash] options
  # @option options [Integer,String] :version
  # @option options [String] :community
  # @option options [Integer] :chosen_pdu Set PDU type
  # @option options [Hash] :pdu Set PDU content
  def initialize(options={})
    super
    data.chosen = options[:chosen_pdu] if options[:chosen_pdu]
    return unless options[:pdu]

    klass = data.root.chosen_value.class
    data.root.value[data.chosen] = klass.new(options[:pdu])
  end

  # accessor to data payload. Shortcut for +snmp[:data]+.
  # @return [ASN1::Types::Choice]
  def data
    @elements[:data]
  end

  # shortcut to PDU (+snmp[:data].chosen_value+).
  # @return [GetRequest, Bulk, Trapv1, nil] return `nil` if no CHOICE was done
  def pdu
    if data.chosen.nil?
      nil
    else
      data.root.chosen_value
    end
  end

  # Inspect SNMP header
  # @return [String]
  def inspect
    str = super
    str << Inspect.shift_level
    str << if self[:data].chosen.nil?
             Inspect::FMT_ATTR % [self[:data].type, :data, '']
           else
             inspect_data
           end
  end

  # @api private
  # @note This method is used internally by PacketGen and should not be
  #       directly called
  # @param [Packet] packet
  # @return [void]
  # @since 2.7.0 Set UDP sport according to bindings, only if sport is not set yet (i.e. is zero).
  #  Needed by new bind API.
  def added_to_packet(packet)
    return unless packet.is?('UDP')
    return unless packet.udp.sport.zero?

    packet.udp.sport = packet.udp.dport
  end

  private

  def inspect_data
    data = self[:data]
    str = Inspect::FMT_ATTR % [data.type, :data, data.chosen_value.type]
    str << Inspect.dashed_line('ASN.1 content')
    str << data.chosen_value.inspect(1)
    begin
      str << Inspect.inspect_body(self[:message].to_der, 'ASN.1 DER')
    rescue StandardError => e
      raise unless e.message.match?(/TAG.*not handled/)
    end
    str
  end
end

Instance Method Details

#added_to_packet(packet) ⇒ void

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.

Note:

This method is used internally by PacketGen and should not be directly called

This method returns an undefined value.

Parameters:

Since:

  • 2.7.0 Set UDP sport according to bindings, only if sport is not set yet (i.e. is zero). Needed by new bind API.


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# File 'lib/packetgen/header/snmp.rb', line 422

def added_to_packet(packet)
  return unless packet.is?('UDP')
  return unless packet.udp.sport.zero?

  packet.udp.sport = packet.udp.dport
end

#data ⇒ ASN1::Types::Choice

accessor to data payload. Shortcut for snmp[:data].

Returns:

  • (ASN1::Types::Choice)

Since:

  • 2.0.0


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# File 'lib/packetgen/header/snmp.rb', line 389

def data
  @elements[:data]
end

#inspect ⇒ String

Inspect SNMP header

Returns:

  • (String)

Since:

  • 2.0.0


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# File 'lib/packetgen/header/snmp.rb', line 405

def inspect
  str = super
  str << Inspect.shift_level
  str << if self[:data].chosen.nil?
           Inspect::FMT_ATTR % [self[:data].type, :data, '']
         else
           inspect_data
         end
end

#pdu ⇒ GetRequest, ...

shortcut to PDU (snmp[:data].chosen_value).

Returns:

Since:

  • 2.0.0


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# File 'lib/packetgen/header/snmp.rb', line 395

def pdu
  if data.chosen.nil?
    nil
  else
    data.root.chosen_value
  end
end