snmp_pdus (snmp v5.20.1)

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Encode and Decode Functions for SNMP PDUs

RFC1157, RFC1905 and/or RFC2272 should be studied carefully before using this module, snmp_pdus.

The module snmp_pdus contains functions for encoding and decoding of SNMP protocol data units (PDUs). In short, this module converts a list of bytes to Erlang record representations and vice versa. The record definitions can be found in the file snmp/include/snmp_types.hrl. If snmpv3 is used, the module that includes snmp_types.hrl must define the constant SNMP_USE_V3 before the header file is included. Example:

-define(SNMP_USE_V3, true).
-include_lib("snmp/include/snmp_types.hrl").

Encoding and decoding must be done explicitly when writing your own Net if process.

Summary

Types

message()

The message is version dependent. 'vsn_hdr' is either a community string (v1 and v2) or a 'v3_hdr' record (v3). 'data' is either a PDU (v1 and v2c) or a (possibly encrypted) 'scopedPdu'.

msg_id()
msg_security_model()
pdu()
pdu_type()
scoped_pdu()
trappdu()
usm_security_parameters()
v3_hdr()
version()

Functions

dec_message(Bytes)

Decodes a list of bytes into an SNMP Message. Note, if there is a v3 message, the msgSecurityParameters are not decoded. They must be explicitly decoded by a call to a security model specific decoding function, e.g. dec_usm_security_parameters/1. Also note, if the scopedPDU is encrypted, the OCTET STRING encoded encryptedPDU will be present in the data field.

dec_message_only(Bytes)

Decodes a list of bytes into an SNMP Message, but does not decode the data part of the Message. That means, data is still a list of bytes, normally an encoded PDU (v1 and V2) or an encoded and possibly encrypted scopedPDU (v3).

dec_pdu(Bytes)

Decodes a list of bytes into an SNMP Pdu.

dec_scoped_pdu(Bytes)

Decodes a list of bytes into an SNMP ScopedPdu.

dec_scoped_pdu_data(Bytes)

Decodes a list of bytes into either a scoped pdu record, or - if the scoped pdu was encrypted - to a list of bytes.

dec_usm_security_parameters(Bytes)

Decodes a list of bytes into an SNMP UsmSecurityParameters.

enc_message(Message)

Encodes a message record to a list of bytes.

enc_message_only(Message)

Message is a record where the data field is assumed to be encoded (a list of bytes). If there is a v1 or v2 message, the data field is an encoded PDU, and if there is a v3 message, data is an encoded and possibly encrypted scopedPDU.

enc_pdu(Pdu)

Encodes an SNMP Pdu into a list of bytes.

enc_scoped_pdu(ScopedPdu)

Encodes an SNMP ScopedPdu into a list of bytes, which can be encrypted, and after encryption, encoded with a call to enc_encrypted_scoped_pdu/1; or it can be used as the data field in a message record, which then can be encoded with enc_message_only/1.

enc_usm_security_parameters(UsmSecParams)

Encodes SNMP UsmSecurityParameters into a list of bytes.

Types

message()

-type message() :: #message{version :: term(), vsn_hdr :: term(), data :: term()}.

The message is version dependent. 'vsn_hdr' is either a community string (v1 and v2) or a 'v3_hdr' record (v3). 'data' is either a PDU (v1 and v2c) or a (possibly encrypted) 'scopedPdu'.

msg_id()

-type msg_id() :: 0..2147483647.

msg_security_model()

-type msg_security_model() :: 0..2147483647.

pdu()

-type pdu() ::
          #pdu{type :: term(),
               request_id :: term(),
               error_status :: term(),
               error_index :: term(),
               varbinds :: term()}.

pdu_type()

-type pdu_type() ::
          'get-request' | 'get-next-request' | 'get-bulk-request' | 'get-response' | 'set-request' |
          'inform-request' | 'snmpv2-trap' | report.

scoped_pdu()

-type scoped_pdu() :: #scopedPdu{contextEngineID :: term(), contextName :: term(), data :: term()}.

trappdu()

-type trappdu() ::
          #trappdu{enterprise :: term(),
                   agent_addr :: term(),
                   generic_trap :: term(),
                   specific_trap :: term(),
                   time_stamp :: term(),
                   varbinds :: term()}.

usm_security_parameters()

-type usm_security_parameters() ::
          #usmSecurityParameters{msgAuthoritativeEngineID :: term(),
                                 msgAuthoritativeEngineBoots :: term(),
                                 msgAuthoritativeEngineTime :: term(),
                                 msgUserName :: term(),
                                 msgAuthenticationParameters :: term(),
                                 msgPrivacyParameters :: term()}.

v3_hdr()

-type v3_hdr() ::
          #v3_hdr{msgID :: term(),
                  msgMaxSize :: term(),
                  msgFlags :: term(),
                  msgSecurityModel :: term(),
                  msgSecurityParameters :: term(),
                  hdr_size :: term()}.

version()

-type version() :: 'version-1' | 'version-2' | 'version-3'.

Functions

dec_message(Bytes :: [byte()]) -> Message

Types

Message = message()

Decodes a list of bytes into an SNMP Message. Note, if there is a v3 message, the msgSecurityParameters are not decoded. They must be explicitly decoded by a call to a security model specific decoding function, e.g. dec_usm_security_parameters/1. Also note, if the scopedPDU is encrypted, the OCTET STRING encoded encryptedPDU will be present in the data field.

dec_message_only(Bytes :: [byte()]) -> Message

Types

Message = message()

Decodes a list of bytes into an SNMP Message, but does not decode the data part of the Message. That means, data is still a list of bytes, normally an encoded PDU (v1 and V2) or an encoded and possibly encrypted scopedPDU (v3).

dec_pdu(Bytes :: [byte()]) -> Pdu

Types

Pdu = trappdu() | pdu()

Decodes a list of bytes into an SNMP Pdu.

dec_scoped_pdu(Bytes :: [byte()]) -> ScopedPDU

Types

ScopedPDU = scoped_pdu()

Decodes a list of bytes into an SNMP ScopedPdu.

dec_scoped_pdu_data(Bytes :: [byte()]) -> ScopedPduData

Types

Bytes = EncryptedPDU = [byte()]
ScopedPduData = scoped_pdu() | EncryptedPDU

Decodes a list of bytes into either a scoped pdu record, or - if the scoped pdu was encrypted - to a list of bytes.

dec_usm_security_parameters(Bytes :: [byte()]) -> UsmSecParams

Types

UsmSecParams = usm_security_parameters()

Decodes a list of bytes into an SNMP UsmSecurityParameters.

enc_message(Message :: message()) -> Bytes

Types

Bytes = [byte()]

Encodes a message record to a list of bytes.

enc_message_only(Message :: message()) -> Bytes

Types

Bytes = [byte()]

Message is a record where the data field is assumed to be encoded (a list of bytes). If there is a v1 or v2 message, the data field is an encoded PDU, and if there is a v3 message, data is an encoded and possibly encrypted scopedPDU.

enc_pdu(Pdu :: pdu()) -> Bytes

Types

Bytes = [byte()]

Encodes an SNMP Pdu into a list of bytes.

enc_scoped_pdu(ScopedPdu :: scoped_pdu()) -> Bytes

Types

Bytes = [byte()]

Encodes an SNMP ScopedPdu into a list of bytes, which can be encrypted, and after encryption, encoded with a call to enc_encrypted_scoped_pdu/1; or it can be used as the data field in a message record, which then can be encoded with enc_message_only/1.

enc_usm_security_parameters(UsmSecParams :: usm_security_parameters()) -> Bytes

Types

Bytes = [byte()]

Encodes SNMP UsmSecurityParameters into a list of bytes.