snmpa_discovery_handler behaviour (snmp v5.18.1)

Behaviour module for the SNMP agent discovery handler.

This module defines the behaviour of the agent discovery handler. A snmpa_discovery_handler compliant module must export the following functions:

stage1_finish/3

The semantics of them and their exact signatures are explained below.

Summary

Callbacks

stage1_finish(TargetName, ManagerEngineID, ExtraInfo)

This function is called at the end of stage 1 of the discovery process. It should return either the atom ignore or {ok, usm_entry() | [usm_entry()]}. See usm_entry() and usm_entry/1,3 for more info.

Callbacks

stage1_finish(TargetName, ManagerEngineID, ExtraInfo)

-callback stage1_finish(TargetName, ManagerEngineID, ExtraInfo) ->
                           ignore | {ok, UsmEntry | [UsmEntry]} | {ok, UsmEntry | [UsmEntry], NewExtraInfo}
                           when
                               TargetName :: snmp_target_mib:name(),
                               ManagerEngineID :: snmp_framework_mib:engine_id(),
                               ExtraInfo :: term(),
                               UsmEntry :: snmp_user_based_sm_mib:usm_entry(),
                               NewExtraInfo :: term().

If the function returns ignore, then it is assumed that either:

The caller (of the discovery function) will make the needed updates later.
The callback function itself did the updates.

In either case, the agent will do nothing, but return the retrieved ManagerEngineID (see snmpa:discovery/6 for more info) and possible continue with stage 2 of the discovery process.

The ExtraInfo argument is passed on from the snmpa:discovery/6 function.

This function may return an updated NewExtraInfo that will be used in subsequent calls to the callback functions. Intended for future use.

The purpose of this function is to generate the usm- related security data needed for usm processing in the agent. Specifically, updating the usmUserTable.

When an usm_entry() tuple (or a list of such tuples) is returned, this data is then added to the usmUserTable by the (master-) agent.

Note

Note that the function does not check if this entry already exists.

Note

Note that this function is executed in the context of the master-agent process.