View Source snmpm_mpd (snmp v5.16)

Message Processing and Dispatch module for the SNMP manager

The module snmpm_mpd implements the version independent Message Processing and Dispatch functionality in SNMP for the manager. It is supposed to be used from a Network Interface process (Definition of Manager Net if).

Legacy API function process_msg/7 that has got separate IpAddr and PortNumber arguments still works as before for backwards compatibility reasons.

Summary

Types

logger()

A fun that handles audit trail logging.

mpd_state()

msg_data_acm()

Is an opaque data structure containing necessary security information for (incoming) v3 messages.

msg_data_cmy()

Is an opaque data structure containing necessary security information for v1 and v2 messages.

msg_data_cmyt()

Is an opaque data structure containing necessary security and transport information for v1 and v2 messages.

msg_data_v3()

Is an opaque data structure containing necessary security information for v3 messages.

Functions

generate_msg(Vsn, NoteStore, Pdu, MsgData, Log)

Generates a possibly encrypted packet to be sent to the network.

generate_response_msg(Vsn, Pdu, MsgData, Log)

Generates a possibly encrypted response packet to be sent to the network.

init(Vsns)

This function can be called from the net_if process at start-up. The options list defines which versions to use.

process_msg(Msg, Domain, Addr, State, NoteStore, Log)

Processes an incoming message. Performs authentication and decryption as necessary. The return values should be passed the manager server.

Types

logger()

-type logger() ::
    fun((Data ::
             binary() |
             snmp_pdus:pdu() |
             snmp_pdus:trappdu() |
             snmp_pdus:message() |
             {V3Hdr :: snmp_pdus:v3_hdr(), ScopedPDUBytes :: binary()}) ->
            snmp:void()).

A fun that handles audit trail logging.

mpd_state()

-opaque mpd_state()

msg_data_acm()

-opaque msg_data_acm()

Is an opaque data structure containing necessary security information for (incoming) v3 messages.

msg_data_cmy()

-opaque msg_data_cmy()

Is an opaque data structure containing necessary security information for v1 and v2 messages.

msg_data_cmyt()

-opaque msg_data_cmyt()

Is an opaque data structure containing necessary security and transport information for v1 and v2 messages.

msg_data_v3()

-opaque msg_data_v3()

Is an opaque data structure containing necessary security information for v3 messages.

Functions

generate_msg(Vsn, NoteStore, Pdu, MsgData, Log)

-spec generate_msg(Vsn, NoteStore, Pdu, MsgData, Log) -> {ok, Packet} | {discarded, Reason}
                when
                    Vsn :: snmp_pdus:version(),
                    NoteStore :: pid(),
                    Pdu :: snmp_pdus:pdu(),
                    MsgData :: msg_data_cmy() | msg_data_v3(),
                    Log :: logger(),
                    Packet :: binary(),
                    Reason :: term().

Generates a possibly encrypted packet to be sent to the network.

NoteStore is the pid/0 of the note-store process.

MsgData is the message specific data used in the SNMP message. In SNMPv1 and SNMPv2c, this message data is the community string. In SNMPv3, it is the context information.

Logger is the function used for audit trail logging.

generate_response_msg(Vsn, Pdu, MsgData, Log)

-spec generate_response_msg(Vsn, Pdu, MsgData, Log) ->
                         {ok, Packet} | {discarded, Reason} | {error, Reason}
                         when
                             Vsn :: snmp_pdus:version(),
                             Pdu :: snmp_pdus:pdu(),
                             MsgData :: msg_data_cmy() | msg_data_cmyt() | msg_data_v3(),
                             Log :: logger(),
                             Packet :: binary(),
                             Reason :: term().

Generates a possibly encrypted response packet to be sent to the network.

MsgData is the message specific data used in the SNMP message. This value is received from the process_msg function.

init(Vsns)

-spec init(Vsns) -> MPDState when Vsns :: [snmp:version()], MPDState :: mpd_state().

This function can be called from the net_if process at start-up. The options list defines which versions to use.

It also initializes some SNMP counters.

process_msg(Msg, Domain, Addr, State, NoteStore, Log)

(since OTP 17.3)

-spec process_msg(Msg, Domain, Addr, State, NoteStore, Log) ->
               {ok, Vsn, PduV2, PduMS, MsgDataV2} |
               {ok, 'version-3', PduV3, PduMS, MsgDataV3} |
               {discarded, Reason}
               when
                   Msg :: binary(),
                   Domain :: snmpUDPDomain | snmp:tdomain(),
                   Addr :: {Ip, Port},
                   Ip :: inet:ip_address(),
                   Port :: inet:port_number(),
                   State :: mpd_state(),
                   NoteStore :: pid(),
                   Log :: logger(),
                   Vsn :: 'version-1' | 'version-2',
                   PduV2 :: snmp_pdus:pdu() | snmp_pdus:trappdu(),
                   PduV3 :: snmp_pdus:pdu(),
                   PduMS :: pos_integer(),
                   MsgDataV2 :: msg_data_cmyt(),
                   MsgDataV3 :: ok | {error, ReqId, ACM} | undefined | msg_data_acm(),
                   ReqId :: snmpm:request_id(),
                   ACM :: term(),
                   Reason :: term().

Processes an incoming message. Performs authentication and decryption as necessary. The return values should be passed the manager server.

NoteStore is the pid/0 of the note-store process.

Logger is the function used for audit trail logging.

In the case when the pdu type is report, MsgData is either ok or {error, ReqId, Reason}.