snmpm_user
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
-
handle_invalid_result/2
The semantics of them and their exact signatures are explained below.
Some of the function has no defined return value (void()
),
they can ofcourse return anythyng. But the functions that do have
specified return value(s) must adhere to this. None of the
functions can use exit of throw to return.
DATA TYPES
snmp_gen_info() = {ErrorStatus :: atom(), ErrorIndex :: pos_integer(), Varbinds :: [snmp:varbind()]} snmp_v1_trap_info() :: {Enteprise :: snmp:oid(), Generic :: integer(), Spec :: integer(), Timestamp :: integer(), Varbinds :: [snmp:varbind()]}
Functions
handle_error(ReqId, Reason, UserData) -> void()
ReqId = integer()
Reason = {unexpected_pdu, SnmpInfo} | {invalid_sec_info, SecInfo, SnmpInfo} | {empty_message, Addr, Port} | term()
SnmpInfo = snmp_gen_info()
SecInfo = term()
Addr = ip_address()
Port = integer()
UserData = term()
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
SnmpPduInfo = snmp_gen_info()
SnmpTrapInfo = snmp_v1_trap_info()
SnmpReportInfo = snmp_gen_info()
SnmpInformInfo = snmp_gen_info()
UserData = term()
Reply = ignore | {register, UserId, TargetName, AgentConfig}
UserId = term()
TargetName = target_name()
AgentConfig = [agent_config()]
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_config()
, see
register_agent.
The arguments Type
and SnmpInfo
relates in the
following way:
-
pdu
-SnmpPduInfo
(see handle_pdu for more info). -
trap
-SnmpTrapInfo
(see handle_trap for more info). -
report
-SnmpReportInfo
(see handle_report for more info). -
inform
-SnmpInformInfo
(see handle_inform for more info).
The only user which would return
{register, UserId, TargetName, AgentConfig}
is the
default user.
handle_pdu(TargetName, ReqId, SnmpPduInfo, UserData) -> void()
TargetName = target_name()
ReqId = term()
SnmpPduInfo = snmp_gen_info()
UserData = term()
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 = snmp_v1_trap_info() | snmp_gen_info()
UserData = term()
Reply = ignore | unregister | {register, UserId, TargetName2, AgentConfig}
UserId = term()
AgentConfig = [agent_config()]
Handle a trap/notification message from an agent.
For more info about the agent_config()
, 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 = snmp_gen_info()
UserData = term()
Reply = ignore | no_reply | unregister | {register, UserId, TargetName2, AgentConfig}
UserId = term()
AgentConfig = [agent_config()]
Handle a inform message.
For more info about the agent_config()
, see
register_agent
The only user which would return
{register, UserId, TargetName2, AgentConfig}
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 = snmp_gen_info()
UserData = term()
Reply = ignore | unregister | {register, UserId, TargetName2, AgentConfig}
UserId = term()
AgentConfig = [agent_config()]
Handle a report message.
For more info about the agent_config()
, see
register_agent
The only user which would return
{register, UserId, TargetName2, AgentConfig}
is the
default user.
handle_invalid_result(IN, OUT) -> void()
IN = {Func, Args}
Func = atom()
Args = list()
OUT = {crash, CrashInfo} | {result, InvalidResult}
CrashInfo = {ErrorType, Error, Stacktrace}
ErrorType = atom()
Error = term()
Stacktrace = list()
InvalidResult = term()
If any of the other callback functions crashes (exit, throw or a plain crash) or return an invalid result (if a valid return has been specified), this function is called. The purpose is to allow the user handle this error (for instance to issue an error report).
IN
reprecents the function called (and its arguments).
OUT
represents the unexpected/invalid result.