382 lines
11 KiB
Ruby
382 lines
11 KiB
Ruby
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#
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# Copyright (c) 2004 David R. Halliday
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# All rights reserved.
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#
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# This SNMP library is free software. Redistribution is permitted under the
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# same terms and conditions as the standard Ruby distribution. See the
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# COPYING file in the Ruby distribution for details.
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#
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require 'snmp/ber'
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require 'snmp/varbind'
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include SNMP::BER
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module SNMP
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# Exceptions thrown during message/pdu decoding
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class UnsupportedVersion < RuntimeError; end
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class UnsupportedPduTag < RuntimeError; end
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class InvalidPduTag < RuntimeError; end
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class ParseError < RuntimeError; end
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class InvalidErrorStatus < RuntimeError; end
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class InvalidTrapVarbind < RuntimeError; end
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class InvalidGenericTrap < RuntimeError; end
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SYS_UP_TIME_OID = ObjectId.new("1.3.6.1.2.1.1.3.0")
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SNMP_TRAP_OID_OID = ObjectId.new("1.3.6.1.6.3.1.1.4.1.0")
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class Message
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attr_reader :version
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attr_reader :community
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attr_reader :pdu
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class << self
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def decode(data)
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message_data, remainder = decode_sequence(data)
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assert_no_remainder(remainder)
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version, remainder = decode_version(message_data)
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community, remainder = decode_octet_string(remainder)
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pdu, remainder = decode_pdu(version, remainder)
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assert_no_remainder(remainder)
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Message.new(version, community, pdu)
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end
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def decode_version(data)
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version_data, remainder = decode_integer(data)
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if version_data == SNMP_V1
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version = :SNMPv1
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elsif version_data == SNMP_V2C
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version = :SNMPv2c
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else
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raise UnsupportedVersion, version_data.to_s
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end
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return version, remainder
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end
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def decode_pdu(version, data)
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pdu_tag, pdu_data, remainder = decode_tlv(data)
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case pdu_tag
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when GetRequest_PDU_TAG
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pdu = PDU.decode(GetRequest, pdu_data)
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when GetNextRequest_PDU_TAG
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pdu = PDU.decode(GetNextRequest, pdu_data)
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when Response_PDU_TAG
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pdu = PDU.decode(Response, pdu_data)
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when SetRequest_PDU_TAG
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pdu = PDU.decode(SetRequest, pdu_data)
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when SNMPv1_Trap_PDU_TAG
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raise InvalidPduTag, "SNMPv1-trap not valid for #{version.to_s}" if version != :SNMPv1
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pdu = SNMPv1_Trap.decode(pdu_data)
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when GetBulkRequest_PDU_TAG
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raise InvalidPduTag, "get-bulk not valid for #{version.to_s}" if version != :SNMPv2c
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pdu = PDU.decode(GetBulkRequest, pdu_data)
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when InformRequest_PDU_TAG
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raise InvalidPduTag, "inform not valid for #{version.to_s}" if version != :SNMPv2c
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pdu = PDU.decode(InformRequest, pdu_data)
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when SNMPv2_Trap_PDU_TAG
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raise InvalidPduTag, "SNMPv2c-trap not valid for #{version.to_s}" if version != :SNMPv2c
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pdu = PDU.decode(SNMPv2_Trap, pdu_data)
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else
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raise UnsupportedPduTag, pdu_tag.to_s
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end
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return pdu, remainder
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end
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end
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def initialize(version, community, pdu)
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@version = version
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@community = community
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@pdu = pdu
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end
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def response
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Message.new(@version, @community, Response.from_pdu(@pdu))
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end
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def encode_version(version)
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if version == :SNMPv1
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encode_integer(SNMP_V1)
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elsif version == :SNMPv2c
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encode_integer(SNMP_V2C)
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else
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raise UnsupportedVersion, version.to_s
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end
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end
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def encode
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data = encode_version(@version)
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data << encode_octet_string(@community)
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data << @pdu.encode
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encode_sequence(data)
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end
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end
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class PDU
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attr_accessor :request_id
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attr_accessor :error_index
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attr_accessor :varbind_list
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alias vb_list varbind_list
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def self.decode(pdu_class, pdu_data)
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request_id, remainder = decode_integer(pdu_data)
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error_status, remainder = decode_integer(remainder)
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error_index, remainder = decode_integer(remainder)
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varbind_list, remainder = VarBindList.decode(remainder)
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assert_no_remainder(remainder)
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pdu_class.new(request_id, varbind_list, error_status, error_index)
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end
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ERROR_STATUS_NAME = {
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0 => :noError,
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1 => :tooBig,
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2 => :noSuchName,
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3 => :badValue,
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4 => :readOnly,
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5 => :genErr,
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6 => :noAccess,
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7 => :wrongType,
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8 => :wrongLength,
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9 => :wrongEncoding,
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10 => :wrongValue,
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11 => :noCreation,
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12 => :inconsistentValue,
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13 => :resourceUnavailable,
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14 => :commitFailed,
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15 => :undoFailed,
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16 => :authorizationError,
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17 => :notWritable,
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18 => :inconsistentName
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}
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ERROR_STATUS_CODE = ERROR_STATUS_NAME.invert
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def initialize(request_id, varbind_list, error_status=0, error_index=0)
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@request_id = request_id
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self.error_status = error_status
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@error_index = error_index.to_int
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@varbind_list = varbind_list
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end
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def error_status=(status)
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@error_status = ERROR_STATUS_CODE[status]
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unless @error_status
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if status.respond_to?(:to_int) && ERROR_STATUS_NAME[status.to_int]
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@error_status = status
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else
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raise InvalidErrorStatus, status.to_s
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end
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end
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end
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def error_status
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ERROR_STATUS_NAME[@error_status]
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end
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def encode_pdu(pdu_tag)
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pdu_data = encode_integer(@request_id)
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pdu_data << encode_integer(@error_status)
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pdu_data << encode_integer(@error_index)
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pdu_data << @varbind_list.encode
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encode_tlv(pdu_tag, pdu_data)
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end
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def each_varbind(&block)
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@varbind_list.each(&block)
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end
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end
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class GetRequest < PDU
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def encode
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encode_pdu(GetRequest_PDU_TAG)
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end
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end
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class GetNextRequest < PDU
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def encode
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encode_pdu(GetNextRequest_PDU_TAG)
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end
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end
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class SetRequest < PDU
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def encode
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encode_pdu(SetRequest_PDU_TAG)
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end
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end
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class GetBulkRequest < PDU
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alias max_repetitions error_index
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alias max_repetitions= error_index=
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def encode
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encode_pdu(GetBulkRequest_PDU_TAG)
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end
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def non_repeaters=(number)
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@error_status = number
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end
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def non_repeaters
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@error_status
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end
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end
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class Response < PDU
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class << self
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def from_pdu(request)
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Response.new(request.request_id, request.varbind_list,
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:noError, 0)
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end
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end
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def encode
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encode_pdu(Response_PDU_TAG)
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end
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end
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##
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# The PDU class for traps in SNMPv2c. Methods are provided for retrieving
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# the values of the mandatory varbinds: the system uptime and the OID of the
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# trap. The complete varbind list is available through the usual varbind_list
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# method. The first two varbinds in this list will always be the uptime
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# and trap OID varbinds.
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#
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class SNMPv2_Trap < PDU
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def encode
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encode_pdu(SNMPv2_Trap_PDU_TAG)
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end
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##
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# Returns the source IP address for the trap, usually derived from the
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# source IP address of the packet that delivered the trap.
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#
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attr_accessor :source_ip
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##
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# Returns the value of the mandatory sysUpTime varbind for this trap.
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#
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# Throws InvalidTrapVarbind if the sysUpTime varbind is not present.
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#
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def sys_up_time
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varbind = @varbind_list[0]
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if varbind && (varbind.name == SYS_UP_TIME_OID)
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return varbind.value
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else
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raise InvalidTrapVarbind, "Expected sysUpTime.0, found " + varbind.to_s
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end
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end
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##
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# Returns the value of the mandatory snmpTrapOID varbind for this trap.
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#
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# Throws InvalidTrapVarbind if the snmpTrapOID varbind is not present.
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#
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def trap_oid
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varbind = @varbind_list[1]
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if varbind && (varbind.name == SNMP_TRAP_OID_OID)
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return varbind.value
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else
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raise InvalidTrapVarbind, "Expected snmpTrapOID.0, found " + varbind.to_s
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end
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end
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end
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##
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# The PDU class for SNMPv2 Inform notifications. This class is identical
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# to SNMPv2_Trap.
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#
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class InformRequest < SNMPv2_Trap
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def encode
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encode_pdu(InformRequest_PDU_TAG)
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end
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end
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##
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# The PDU class for traps in SNMPv1.
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#
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class SNMPv1_Trap
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##
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# Returns the source IP address for the trap, usually derived from the
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# source IP address of the packet that delivered the trap.
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#
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attr_accessor :source_ip
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attr_accessor :enterprise
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attr_accessor :agent_addr
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attr_accessor :specific_trap
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attr_accessor :timestamp
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attr_accessor :varbind_list
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alias :vb_list :varbind_list
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def self.decode(pdu_data)
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oid_data, remainder = decode_object_id(pdu_data)
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enterprise = ObjectId.new(oid_data)
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ip_data, remainder = decode_ip_address(remainder)
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agent_addr = IpAddress.new(ip_data)
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generic_trap, remainder = decode_integer(remainder)
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specific_trap, remainder = decode_integer(remainder)
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time_data, remainder = decode_timeticks(remainder)
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timestamp = TimeTicks.new(time_data)
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varbind_list, remainder = VarBindList.decode(remainder)
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assert_no_remainder(remainder)
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SNMPv1_Trap.new(enterprise, agent_addr, generic_trap, specific_trap,
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timestamp, varbind_list)
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end
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def initialize(enterprise, agent_addr, generic_trap, specific_trap, timestamp, varbind_list)
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@enterprise = enterprise
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@agent_addr = agent_addr
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self.generic_trap = generic_trap
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@specific_trap = specific_trap
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@timestamp = timestamp
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@varbind_list = varbind_list
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end
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# Name map for all of the generic traps defined in RFC 1157.
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GENERIC_TRAP_NAME = {
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0 => :coldStart,
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1 => :warmStart,
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2 => :linkDown,
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3 => :linkUp,
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4 => :authenticationFailure,
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5 => :egpNeighborLoss,
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6 => :enterpriseSpecific
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}
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# Code map for all of the generic traps defined in RFC 1157.
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GENERIC_TRAP_CODE = GENERIC_TRAP_NAME.invert
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def generic_trap=(trap)
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@generic_trap = GENERIC_TRAP_CODE[trap]
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unless @generic_trap
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if trap.respond_to?(:to_i) && GENERIC_TRAP_NAME[trap.to_i]
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@generic_trap = trap
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else
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raise InvalidGenericTrap, trap.to_s
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end
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end
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end
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def generic_trap
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GENERIC_TRAP_NAME[@generic_trap]
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end
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def encode
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pdu_data = @enterprise.encode <<
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@agent_addr.encode <<
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encode_integer(@generic_trap) <<
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encode_integer(@specific_trap) <<
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@timestamp.encode <<
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@varbind_list.encode
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encode_tlv(SNMPv1_Trap_PDU_TAG, pdu_data)
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end
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def each_varbind(&block)
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@varbind_list.each(&block)
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end
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end
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end
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