295 lines
9 KiB
Elixir
295 lines
9 KiB
Elixir
defmodule SnmpKit.SnmpLib.PDU.Constants do
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@moduledoc """
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Constants and type definitions for SNMP PDU operations.
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This module contains all ASN.1 tags, error codes, type definitions,
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and utility functions used throughout the SNMP PDU system.
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"""
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import Bitwise
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# Type definitions
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@type snmp_type ::
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:integer
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| :octet_string
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| :null
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| :object_identifier
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| :counter32
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| :gauge32
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| :timeticks
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| :counter64
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| :ip_address
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| :opaque_type
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| :no_such_object
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| :no_such_instance
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| :end_of_mib_view
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# SNMP PDU Types
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@get_request 0xA0
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@getnext_request 0xA1
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@get_response 0xA2
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@set_request 0xA3
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@getbulk_request 0xA5
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# SNMP Data Types
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@integer 0x02
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@octet_string 0x04
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@null 0x05
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@object_identifier 0x06
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@counter32 0x41
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@gauge32 0x42
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@timeticks 0x43
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@counter64 0x46
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@ip_address 0x40
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@opaque_type 0x44
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@no_such_object 0x80
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@no_such_instance 0x81
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@end_of_mib_view 0x82
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# SNMP Error Status Codes
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@no_error 0
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@too_big 1
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@no_such_name 2
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@bad_value 3
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@read_only 4
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@gen_err 5
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@type snmp_version :: :v1 | :v2c | :v2 | :v3 | 0 | 1 | 3
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@type pdu_type ::
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:get_request | :get_next_request | :get_response | :set_request | :get_bulk_request
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@type error_status :: 0..18
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@type oid :: [non_neg_integer()] | binary()
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@type snmp_value :: any()
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@type varbind :: {oid(), atom(), snmp_value()}
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@type base_pdu :: %{
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type: pdu_type(),
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request_id: non_neg_integer(),
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error_status: error_status(),
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error_index: non_neg_integer(),
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varbinds: [varbind()]
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}
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@type bulk_pdu :: %{
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type: :get_bulk_request,
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request_id: non_neg_integer(),
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error_status: error_status(),
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error_index: non_neg_integer(),
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varbinds: [varbind()],
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non_repeaters: non_neg_integer(),
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max_repetitions: non_neg_integer()
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}
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@type pdu :: base_pdu() | bulk_pdu()
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# SNMPv1/v2c message format
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@type v1v2c_message :: %{
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version: snmp_version() | non_neg_integer(),
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community: binary(),
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pdu: pdu()
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}
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# SNMPv3 message format
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@type v3_message :: %{
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version: 3,
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msg_id: non_neg_integer(),
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msg_max_size: non_neg_integer(),
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msg_flags: binary(),
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msg_security_model: non_neg_integer(),
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msg_security_parameters: binary(),
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msg_data: scoped_pdu()
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}
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@type message :: v1v2c_message() | v3_message()
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# SNMPv3 specific types
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@type scoped_pdu :: %{
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context_engine_id: binary(),
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context_name: binary(),
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pdu: pdu()
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}
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@type msg_flags :: %{
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auth: boolean(),
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priv: boolean(),
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reportable: boolean()
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}
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# Error status code accessors
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def no_error, do: @no_error
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def too_big, do: @too_big
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def no_such_name, do: @no_such_name
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def bad_value, do: @bad_value
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def read_only, do: @read_only
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def gen_err, do: @gen_err
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# SNMPv3 constants
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@usm_security_model 3
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@default_max_message_size 65_507
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def usm_security_model, do: @usm_security_model
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def default_max_message_size, do: @default_max_message_size
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# PDU type constants accessors
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def get_request, do: @get_request
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def getnext_request, do: @getnext_request
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def get_response, do: @get_response
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def set_request, do: @set_request
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def getbulk_request, do: @getbulk_request
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# Data type constants accessors
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def integer, do: @integer
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def octet_string, do: @octet_string
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def null, do: @null
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def object_identifier, do: @object_identifier
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def counter32, do: @counter32
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def gauge32, do: @gauge32
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def timeticks, do: @timeticks
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def counter64, do: @counter64
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def ip_address, do: @ip_address
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def opaque_type, do: @opaque_type
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def no_such_object, do: @no_such_object
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def no_such_instance, do: @no_such_instance
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def end_of_mib_view, do: @end_of_mib_view
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# Utility functions moved from main module
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def normalize_version(:v1), do: 0
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def normalize_version(:v2c), do: 1
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def normalize_version(:v2), do: 1
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def normalize_version(:v3), do: 3
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def normalize_version(v) when is_integer(v), do: v
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def normalize_version(_), do: 0
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def normalize_oid(oid) when is_list(oid), do: oid
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def normalize_oid(oid) when is_binary(oid) do
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oid
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|> String.split(".")
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|> Enum.map(fn part ->
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case Integer.parse(part) do
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{num, ""} when num >= 0 -> num
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_ -> throw(:invalid_oid)
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end
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end)
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catch
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# Safe default for invalid OID strings
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:invalid_oid -> [1, 3, 6, 1]
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end
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# Safe default for invalid types
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def normalize_oid(_), do: [1, 3, 6, 1]
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# New utility functions for type conversion
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def pdu_type_to_tag(:get_request), do: @get_request
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def pdu_type_to_tag(:get_next_request), do: @getnext_request
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def pdu_type_to_tag(:get_response), do: @get_response
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def pdu_type_to_tag(:set_request), do: @set_request
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def pdu_type_to_tag(:get_bulk_request), do: @getbulk_request
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def tag_to_pdu_type(@get_request), do: :get_request
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def tag_to_pdu_type(@getnext_request), do: :get_next_request
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def tag_to_pdu_type(@get_response), do: :get_response
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def tag_to_pdu_type(@set_request), do: :set_request
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def tag_to_pdu_type(@getbulk_request), do: :get_bulk_request
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def tag_to_pdu_type(_), do: nil
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def data_type_to_tag(:integer), do: @integer
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def data_type_to_tag(:octet_string), do: @octet_string
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def data_type_to_tag(:null), do: @null
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def data_type_to_tag(:object_identifier), do: @object_identifier
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def data_type_to_tag(:counter32), do: @counter32
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def data_type_to_tag(:gauge32), do: @gauge32
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def data_type_to_tag(:timeticks), do: @timeticks
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def data_type_to_tag(:counter64), do: @counter64
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def data_type_to_tag(:ip_address), do: @ip_address
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def data_type_to_tag(:opaque), do: @opaque_type
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def data_type_to_tag(:no_such_object), do: @no_such_object
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def data_type_to_tag(:no_such_instance), do: @no_such_instance
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def data_type_to_tag(:end_of_mib_view), do: @end_of_mib_view
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def tag_to_data_type(@integer), do: :integer
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def tag_to_data_type(@octet_string), do: :octet_string
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def tag_to_data_type(@null), do: :null
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def tag_to_data_type(@object_identifier), do: :object_identifier
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def tag_to_data_type(@counter32), do: :counter32
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def tag_to_data_type(@gauge32), do: :gauge32
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def tag_to_data_type(@timeticks), do: :timeticks
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def tag_to_data_type(@counter64), do: :counter64
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def tag_to_data_type(@ip_address), do: :ip_address
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def tag_to_data_type(@opaque_type), do: :opaque
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def tag_to_data_type(@no_such_object), do: :no_such_object
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def tag_to_data_type(@no_such_instance), do: :no_such_instance
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def tag_to_data_type(@end_of_mib_view), do: :end_of_mib_view
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def tag_to_data_type(_), do: nil
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@doc """
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Normalizes an SNMP type atom.
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"""
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@spec normalize_type(atom()) :: snmp_type()
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def normalize_type(:string), do: :octet_string
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def normalize_type(type), do: type
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@doc """
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Converts an error status atom to its numeric code.
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"""
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@spec error_status_to_code(atom()) :: non_neg_integer()
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def error_status_to_code(:no_error), do: @no_error
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def error_status_to_code(:too_big), do: @too_big
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def error_status_to_code(:no_such_name), do: @no_such_name
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def error_status_to_code(:bad_value), do: @bad_value
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def error_status_to_code(:read_only), do: @read_only
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def error_status_to_code(:gen_err), do: @gen_err
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def error_status_to_code(code) when is_integer(code), do: code
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@doc """
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Converts an error status code to its atom representation.
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"""
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@spec error_status_to_atom(non_neg_integer()) :: atom()
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def error_status_to_atom(@no_error), do: :no_error
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def error_status_to_atom(@too_big), do: :too_big
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def error_status_to_atom(@no_such_name), do: :no_such_name
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def error_status_to_atom(@bad_value), do: :bad_value
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def error_status_to_atom(@read_only), do: :read_only
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def error_status_to_atom(@gen_err), do: :gen_err
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def error_status_to_atom(code), do: code
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@doc """
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Encodes SNMPv3 message flags to binary format.
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"""
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@spec encode_msg_flags(msg_flags()) :: binary()
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def encode_msg_flags(%{auth: auth, priv: priv, reportable: reportable}) do
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flags = 0
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flags = if auth, do: flags ||| 0x01, else: flags
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flags = if priv, do: flags ||| 0x02, else: flags
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flags = if reportable, do: flags ||| 0x04, else: flags
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<<flags>>
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end
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@doc """
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Decodes SNMPv3 message flags from binary format.
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"""
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@spec decode_msg_flags(binary()) :: msg_flags()
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def decode_msg_flags(<<flags::8>>) do
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%{
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auth: (flags &&& 0x01) != 0,
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priv: (flags &&& 0x02) != 0,
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reportable: (flags &&& 0x04) != 0
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}
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end
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@doc """
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Creates default SNMPv3 message flags for a security level.
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"""
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@spec default_msg_flags(atom()) :: msg_flags()
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def default_msg_flags(:no_auth_no_priv) do
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%{auth: false, priv: false, reportable: true}
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end
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def default_msg_flags(:auth_no_priv) do
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%{auth: true, priv: false, reportable: true}
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end
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def default_msg_flags(:auth_priv) do
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%{auth: true, priv: true, reportable: true}
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end
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end
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