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:
The semantics of them and their exact signatures are explained below.
Functions
TargetName = string()
ManagerEngineID = string()
ExtraInfo = term()
usm_entry() = tuple() compatible with usm.conf
NewExtraInfo = term()
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/13
for more info.
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 discovery for more info) and possible continue with stage 2 of the discovery process.
The ExtraInfo
argument is passed on from the
discovery
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.
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.