# snmpm_user

### MODULE

snmpm_user

### MODULE SUMMARY

Behaviour module for the SNMP manager user.

### DESCRIPTION

This module defines the behaviour of the manager user. A `snmpm_user` compliant module must export the following functions:

- handle_error/3
- handle_agent/4
- handle_pdu/5
- handle_trap/4
- handle_inform/4
- handle_report/4

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

### EXPORTS

`handle_error(ReqId, Reason, UserData) -> Reply`

Types:

`ReqId = integer()`
`Reason = {unexpected_pdu, SnmpInfo} | {invalid_sec_info, SecInfo, SnmpInfo} | {empty_message, Addr, Port} | term()`
`Addr = ip_address()`
`Port = integer()`
`UserData = term()`
`Reply = ignore`

This function is called when the manager needs to communicate an "asynchronous" error, to the user: e.g. failure to send an asynchroneous message (i.e. encoding error), a received message was discarded due to security error, the manager failed to generate a response message to a received inform-request, or when receiving an unexpected PDU from an agent (could be an expired async request).

If `ReqId` is less then 0, it means that this information was not available to the manager (that info was never retrieved before the message was discarded).

For `SnmpInfo` see handle_agent below.

`handle_agent(Addr, Port, SnmpInfo, UserData) -> Reply`

Types:

`Addr = ip_address()`
`Port = integer()`
`SnmpInfo = {ErrorStatus, ErrorIndex, Varbinds}`
`ErrorStatus = atom()`
`ErrorIndex = integer()`
`Varbinds = [varbind()]`
`varbind() = #varbind`
`UserData = term()`
`Reply = ignore | {register, UserId, agent_info()}`
`UserId = term()`
`agent_info() = [{agent_info_item(), agent_info_value()}]`

This function is called when a message is received from an unknown agent.

Note that this will always be the default user that is called.

For more info about the `agent_info()`, see register_agent.

The only user which would return `{register, UserId, agent_info()}` is the default user.

`handle_pdu(Addr, Port, ReqId, SnmpResponse, UserData) -> Reply`

Types:

`Addr = ip_address()`
`Port = integer()`
`ReqId = term()`
`SnmpResponse = {ErrorStatus, ErrorIndex, Varbinds}`
`ErrorStatus = atom()`
`ErrorIndex = integer()`
`Varbinds = [varbind()]`
`varbind() = #varbind`
`UserData = term()`
`Reply = ignore`

Handle the reply to an asynchroneous request, such as ag, agn or as.

It could also be a late reply to a synchroneous request.

`ReqId` is returned by the asynchroneous request function.

`handle_trap(Addr, Port, SnmpTrapInfo, UserData) -> Reply`

Types:

`Addr = ip_address()`
`Port = integer()`
`SnmpTrapInfo = {Enteprise, Generic, Spec, Timestamp, Varbinds} | {ErrorStatus, ErrorIndex, Varbinds}`
`Enterprise = oid()`
`Generic = integer()`
`Spec = integer()`
`Timestamp = integer()`
`ErrorStatus = atom()`
`ErrorIndex = integer()`
`Varbinds = [varbind()]`
`varbind() = #varbind`
`UserData = term()`
`Reply = ignore | unregister | {register, UserId, agent_info()}`
`UserId = term()`
`agent_info() = [{agent_info_item(), agent_info_value()}]`

Handle a trap/notification message from an agent.

For more info about the `agent_info()`, see register_agent

The only user which would return `{register, UserId, agent_info()}` is the default user.

`handle_inform(Addr, Port, SnmpInfo, UserData) -> Reply`

Types:

`Addr = ip_address()`
`Port = integer()`
`SnmpInfo = {ErrorStatus, ErrorIndex, Varbinds}`
`ErrorStatus = atom()`
`ErrorIndex = integer()`
`Varbinds = [varbind()]`
`varbind() = #varbind`
`UserData = term()`
`Reply = ignore | unregister | {register, UserId, agent_info()}`
`UserId = term()`
`agent_info() = [{agent_info_item(), agent_info_value()}]`

Handle a inform message.

For more info about the `agent_info()`, see register_agent

The only user which would return `{register, UserId, agent_info()}` is the default user.

If the inform request behaviour configuration option is set to `user` or `{user, integer()}`, the response (acknowledgement) to this inform-request will be sent when this function returnes.

`handle_report(Addr, Port, SnmpInfo, UserData) -> Reply`

Types:

`Addr = ip_address()`
`Port = integer()`
`SnmpInfo = {ErrorStatus, ErrorIndex, Varbinds}`
`ErrorStatus = atom()`
`ErrorIndex = integer()`
`Varbinds = [varbind()]`
`varbind() = #varbind`
`UserData = term()`
`Reply = ignore | unregister | {register, UserId, agent_info()}`
`UserId = term()`
`agent_info() = [{agent_info_item(), agent_info_value()}]`

Handle a report message.

For more info about the `agent_info()`, see register_agent

The only user which would return `{register, UserId, agent_info()}` is the default user.

### AUTHORS

Micael Karlberg - support@erlang.ericsson.se

snmp 4.8.4
Copyright © 1991-2007 Ericsson AB