snmpm_user

(snmp)

Behaviour module for the SNMP manager user.

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/4

  • handle_trap/3

  • handle_inform/3

  • handle_report/3

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

Note that if an agent is registered using the old, no longer documented, functions (using Addr and Port), the old variant of the callback functions, handle_pdu, handle_trap, handle_inform and handle_report, will be called.

Functions

handle_error(ReqId, Reason, UserData) -> Reply

  • 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 asynchronous 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, Type, SnmpInfo, UserData) -> Reply

  • Addr = ip_address()
  • Port = integer()
  • Type = pdu | trap | report | inform
  • SnmpInfo = SnmpPduInfo | SnmpTrapInfo | SnmpReportInfo | SnmpInformInfo
  • ErrorStatus = atom()
  • ErrorIndex = integer()
  • Varbinds = [varbind()]
  • varbind() = #varbind
  • UserData = term()
  • Reply = ignore | {register, UserId, TargetName, agent_info()}
  • UserId = term()
  • TargetName = target_name()
  • 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 arguments Type and SnmpInfo relates in the following way:

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

handle_pdu(TargetName, ReqId, SnmpPduInfo, UserData) -> Reply

  • TargetName = target_name()
  • ReqId = term()
  • SnmpPduInfo = {ErrorStatus, ErrorIndex, Varbinds}
  • ErrorStatus = atom()
  • ErrorIndex = integer()
  • Varbinds = [varbind()]
  • varbind() = #varbind
  • UserData = term()
  • Reply = ignore

Handle the reply to an asynchronous request, such as async_get, async_get_next or async_set.

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

ReqId is returned by the asynchronous request function.

handle_trap(TargetName, SnmpTrapInfo, UserData) -> Reply

  • TargetName = TargetName2 = target_name()
  • 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, TargetName2, 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, TargetName2, agent_info()} is the default user.

handle_inform(TargetName, SnmpInformInfo, UserData) -> Reply

  • TargetName = TargetName2 = target_name()
  • SnmpInformInfo = {ErrorStatus, ErrorIndex, Varbinds}
  • ErrorStatus = atom()
  • ErrorIndex = integer()
  • Varbinds = [varbind()]
  • varbind() = #varbind
  • UserData = term()
  • Reply = ignore | unregister | {register, UserId, TargetName2, 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, TargetName2, agent_info()} is the default user.

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

handle_report(TargetName, SnmpReportInfo, UserData) -> Reply

  • TargetName = TargetName2 = target_name()
  • Addr = ip_address()
  • Port = integer()
  • SnmpReportInfo = {ErrorStatus, ErrorIndex, Varbinds}
  • ErrorStatus = atom()
  • ErrorIndex = integer()
  • Varbinds = [varbind()]
  • varbind() = #varbind
  • UserData = term()
  • Reply = ignore | unregister | {register, UserId, TargetName2, 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, TargetName2, agent_info()} is the default user.

View Functions