snmpa(3)

MODULE
snmpa - Interface Functions to the SNMP toolkit agent

DESCRIPTION

The module snmpa contains interface functions to the SNMP agent.

Common Data Types

The following datatypes are used in the functions below:

    *   oid() = [byte()]

The oid() type is used to represent an ASN.1 OBJECT IDENTIFIER.

EXPORTS

add_agent_caps(SysORID, SysORDescr) -> SysORIndex

    Types
        SysORID = oid()
        SysORDescr = string()
        SysORIndex = integer()

    This function can be used to add an AGENT-CAPABILITY statement to the sysORTable in the agent. The table is defined in the SNMPv2-MIB.

del_agent_caps(SysORIndex) -> void()

    Types
        SysORIndex = integer()

    This function can be used to delete an AGENT-CAPABILITY statement to the sysORTable in the agent. This table is defined in the SNMPv2-MIB.

get_agent_caps() -> [[SysORIndex, SysORID, SysORDescr, SysORUpTime]]

    Types
        SysORIndex = integer()
        SysORId = oid()
        SysORDescr = string()
        SysORUpTime = integer()

    Returns all AGENT-CAPABILITY statements in the sysORTable in the agent. This table is defined in the SNMPv2-MIB.

get(Agent,Vars) -> Values | {error, Reason}
get(Agent,Vars,Context) -> Values | {error, Reason}

    Types
        Agent = pid() | atom()
        Vars = [oid()]
        Context = string()
        Values = [term()]
        Reason = {atom(), oid()}

    Performs a GET operation on the agent. All loaded MIB objects are visible in this operation. The agent calls the corresponding instrumentation functions just as if it was a GET request coming from a manager.

    Note that the request specific parameters (such as snmpa:current_request_id/0 are not accessible for the instrumentation functions if this function is used.

get_next(Agent,Vars) -> Values | {error, Reason}
get_next(Agent,Vars,Context) -> Values | {error, Reason}

    Types
        Agent = pid() | atom()
        Vars = [oid()]
        Context = string()
        Values = [{oid(), term()}]
        Reason = {atom(), oid()}

    Performs a GET-NEXT operation on the agent. All loaded MIB objects are visible in this operation. The agent calls the corresponding instrumentation functions just as if it was a GET request coming from a manager.

    Note that the request specific parameters (such as snmpa:current_request_id/0 are not accessible for the instrumentation functions if this function is used.

get_symbolic_store_db() -> Db

    Types
        Db = term()

    Retrieve the symbolic store database reference. This is used for faster access to the database using the functions: int_to_enum/3, enum_to_int/3, name_to_oid/2, oid_to_name/2.

info() -> [{Key, Value}]
info(Agent) -> [{Key, Value}]

    Types
        Agent = pid() | atom()

    Returns a list (a dictionary) containing information about the agent. Information includes loaded MIBs, registered subagents, some information about the memory allocation.

load_mibs(Mibs) -> ok | {error, Reason}
load_mibs(Agent,Mibs) -> ok | {error, Reason}

    Types
        Agent = pid() | atom()
        Mibs = [MibName]
        MibName = string()
        Reason = term()

    Loads Mibs into an agent. If the agent cannot load all MIBs, it will indicate where loading was aborted. The MibName is the name of the Mib, including the path to where the compiled mib is found. For example,
              Dir = code:priv_dir(my_app) ++ "/mibs/",
              snmpa:load_mibs(snmp_master_agent, [Dir ++ "MY-MIB"]).

unload_mibs(Mibs) -> ok | {error, Reason}
unload_mibs(Agent,Mibs) -> ok | {error, Reason}

    Types
        Agent = pid() | atom()
        Mibs = [MibName]
        MibName = string()

    Unloads MIBs into an agent. If it cannot unload all MIBs, it will indicate where unloading was aborted.

which_mibs() -> Mibs
which_mibs(Agent) -> Mibs

    Types
        Agent = pid() | atom()
        Mibs = [{MibName, MibFile}]
        MibName = atom()
        MibFile = string()

    Retrieve the list of all the mibs loaded into this agent. Default is the master agent.

whereis_mib(MibName) -> {ok, MibFile} | {error, Reason}
whereis_mib(Agent, MibName) -> {ok, MibFile} | {error, Reason}

    Types
        Agent = pid() | atom()
        MibName = atom()
        MibFile = string()
        Reason = term()

    Get the full path to the (compiled) mib-file.

enum_to_int(Name,Enum) -> {value, Int} | false
enum_to_int(Db,Name,Enum) -> {value, Int} | false

    Types
        Db = term()
        Name = atom()
        Enum = atom()
        Int = int()

    Converts the symbolic value Enum to the corresponding integer of the enumerated object or type Name in a MIB. The MIB must be loaded.

    false is returned if the object or type is not defined in any loaded MIB, or if it does not define the symbolic value as enumerated.

    Db is a reference to the symbolic store database (retrieved by a call to get_symbolic_store_db/0).

int_to_enum(Name,Int) -> {value, Enum} | false
int_to_enum(Db,Name,Int) -> {value, Enum} | false

    Types
        Db = term()
        Name = atom()
        Int = int()
        Enum = atom()

    Converts the integer Int to the corresponding symbolic value of the enumerated object or type Name in a MIB. The MIB must be loaded.

    false is returned if the object or type is not defined in any loaded MIB, or if it does not define the symbolic value as enumerated.

    Db is a reference to the symbolic store database (retrieved by a call to get_symbolic_store_db/0).

name_to_oid(Name) -> {value, oid()} | false
name_to_oid(Db,Name) -> {value, oid()} | false

    Types
        Db = term()
        Name = atom()

    Looks up the OBJECT IDENTIFIER of a MIB object, given the symbolic name. Note, the OBJECT IDENTIFIER is given for the object, not for an instance.

    false is returned if the object is not defined in any loaded MIB.

    Db is a reference to the symbolic store database (retrieved by a call to get_symbolic_store_db/0).

oid_to_name(OID) -> {value, Name} | false
oid_to_name(Db,OID) -> {value, Name} | false

    Types
        Db = term()
        OID = oid()
        Name = atom()

    Looks up the symbolic name of a MIB object, given OBJECT IDENTIFIER.

    false is returned if the object is not defined in any loaded MIB.

    Db is a reference to the symbolic store database (retrieved by a call to get_symbolic_store_db/0).

which_aliasnames() -> Result

    Types
        Result = [atom()]

    Retrieve all alias-names known to the agent.

log_to_txt(LogDir, Mibs)
log_to_txt(LogDir, Mibs, OutFile) -> ok | {error, Reason}
log_to_txt(LogDir, Mibs, OutFile, LogName) -> ok | {error, Reason}
log_to_txt(LogDir, Mibs, OutFile, LogName, LogFile) -> ok | {error, Reason}
log_to_txt(LogDir, Mibs, OutFile, LogName, LogFile, Start) -> ok | {error, Reason}
log_to_txt(LogDir, Mibs, OutFile, LogName, LogFile, Start, Stop) -> ok | {error, Reason}

    Types
        LogDir = string()
        Mibs = [MibName]
        MibName = string()
        OutFile = string()
        LogName = string()
        LogFile = string()
        Start = Stop = null | datetime() | {local_time, datetime()} | {universal_time, datetime()}
        Reason = term()

    Converts an Audit Trail Log to a readable text file. OutFile defaults to "./snmpa_log.txt". LogName defaults to "snmpa_log". LogFile defaults to "snmpa.log". See snmp:log_to_txt for more info.

change_log_size(NewSize) -> ok | {error, Reason}

    Types
        NewSize = {MaxBytes, MaxFiles}
        MaxBytes = integer()
        MaxFiles = integer()
        Reason = term()

    Changes the log size of the Audit Trail Log. The application must be configured to use the audit trail log function. Please refer to disk_log(3) in Kernel Reference Manual for a description of how to change the log size.

    The change is permanent, as long as the log is not deleted. That means, the log size is remebered across reboots.

mib_of(Oid) -> {ok, MibName} | {error, Reason}
mib_of(Agent, Oid) -> {ok, MibName} | {error, Reason}

    Types
        Agent = pid() | atom()
        Oid = oid()
        MibName = atom()
        Reason = term()

    Finds the mib corresponding to the Oid. If it is a variable, the Oid must be <Oid for var>.0 and if it is a table, Oid must be <table>.<entry>.<col>.<any>

me_of(Oid) -> {ok, Me} | {error, Reason}
me_of(Agent, Oid) -> {ok, Me} | {error, Reason}

    Types
        Agent = pid() | atom()
        Oid = oid()
        Me = #me{}
        Reason = term()

    Finds the mib entry corresponding to the Oid. If it is a variable, the Oid must be <Oid for var>.0 and if it is a table, Oid must be <table>.<entry>.<col>.<any>

register_notification_filter(Id, Mod, Data) -> ok | {error, Reason}
register_notification_filter(Agent, Id, Mod, Data) -> ok | {error, Reason}
register_notification_filter(Id, Mod, Data, Where) -> ok | {error, Reason}
register_notification_filter(Agent, Id, Mod, Data, Where) -> ok | {error, Reason}

    Types
        Agent = pid() | atom()
        Id = filter_id()
        filter_id() = term()
        Mod = atom()
        Data = term()
        Where = filter_position()
        Reason = term()
        filter_position() = first | last | {insert_before, filter_id()} | {insert_after, filter_id()}

    Registers a notification filter.

    Mod is a module implementing the snmpa_notification_filter behaviour.

    Data will be passed on to the filter when calling the functions of the behaviour.

unregister_notification_filter(Id) -> ok | {error, Reason}
unregister_notification_filter(Agent, Id) -> ok | {error, Reason}

    Types
        Agent = pid() | atom()
        Id = filter_id()
        filter_id() = term()

    Unregisters a notification filter.

which_notification_filter() -> Filters
which_notification_filter(Agent) -> Filters

    Types
        Agent = pid() | atom()
        Filters = [filter_id()]
        filter_id() = term()

    List all notification filters in an agent.

register_subagent(Agent,SubTreeOid,Subagent) -> ok | {error, Reason}

    Types
        Agent = pid() | atom()
        SubTreeOid = oid()
        SubAgent = pid()

    Registers a subagent under a subtree of another agent.

    It is easy to make mistakes when registering subagents and this activity should be done carefully. For example, a strange behaviour would result from the following configuration:
    snmp_agent:register_subagent(MAPid,[1,2,3,4],SA1),
    snmp_agent:register_subagent(SA1,[1,2,3], SA2).

    SA2 will not get requests starting with object identifier [1, 2, 3] since SA1 does not.

unregister_subagent(Agent,SubagentOidOrPid) -> ok | {ok, SubAgentPid} | {error, Reason}

    Types
        Agent = pid() | atom()
        SubTreeOidorPid = oid() | pid()

    Unregisters a subagent. If the second argument is a pid, then that subagent will be unregistered from all trees in Agent.

send_notification(Agent,Notification,Receiver)
send_notification(Agent,Notification,Receiver,Varbinds)
send_notification(Agent,Notification,Receiver, NotifyName,Varbinds)
send_notification(Agent,Notification,Receiver, NotifyName,ContextName,Varbinds) -> void()

    Types
        Agent = pid() | atom()
        Notification = atom()
        Receiver = no_receiver | {Tag, Recv}
        Tag = term()
        Recv = pid() | atom() | {Mod, Func, Args}
        Mod = atom()
        Func = atom()
        Args = list()
        NotifyName = string()
        ContextName = string()
        Varbinds = [Varbind]
        Varbind = {Variable, Value} | {Column, RowIndex, Value} | {OID, Value}
        Variable = atom()
        Column = atom()
        OID = oid()
        Value = term()
        RowIndex = [int()]

    Sends the notification Notification to the management targets defined for NotifyName in the snmpNotifyTable in SNMP-NOTIFICATION-MIB from the specified context. If no NotifyName is specified (or if it is ""), the notification is sent to all management targets. If no ContextName is specified, the default "" context is used.

    The parameter Receiver specifies where information about delivery of Inform-Requests should be sent. The agent sends Inform-Requests and waits for acknowledgements from the managers. If the Receiver is specified as no_receiver, nothing is sent. Otherwise, it is specified as {Tag, Recv}. The receiver (Recv) gets a message:

        *   {snmp_targets, Tag, Addresses}

    Addresses is a list of management target addresses. If UDP over IP is used, this is a 2-tuple {IP, UDPport}, where IP is a 4-tuple with the IP address, and UDPport is an integer. The notification is sent as an Inform-Request to each target address in Addresses. If there are no targets for which an Inform-Request is sent, Addresses is the empty list [].

    For each such Address is the Addresses list, one of the following two messages is sent to Recv:

        *   {snmp_notification, Tag, {got_response, Address}}

        *   {snmp_notification, Tag, {no_response, Address}}

    The optional argument Varbinds defines values for the objects in the notification. If no value is given for an object, the Agent performs a get-operation to retrieve the value.

    Varbinds is a list of Varbind, where each Varbind is one of:

        *   {Variable, Value}, where Variable is the symbolic name of a scalar variable referred to in the notification specification.

        *   {Column, RowIndex, Value}, where Column is the symbolic name of a column variable. RowIndex is a list of indices for the specified element. If this is the case, the OBJECT IDENTIFIER sent in the notification is the RowIndex appended to the OBJECT IDENTIFIER for the table column. This is the OBJECT IDENTIFIER which specifies the element.

        *   {OID, Value}, where OID is the OBJECT IDENTIFIER for an instance of an object, scalar variable, or column variable.

    For example, to specify that sysLocation should have the value "upstairs" in the notification, we could use one of:

        *   {sysLocation, "upstairs"} or

        *   {[1, 3, 6, 1, 2, 1, 1, 6, 0], "upstairs"} or

        *   {?sysLocation_instance, "upstairs"} (provided that the generated .hrl file is included)

    If a variable in the notification is a table element, the RowIndex for the element must be given in the Varbinds list. In this case, the OBJECT IDENTIFIER sent in the notification is the OBJECT IDENTIFIER that identifies this element. This OBJECT IDENTIFIER could be used in a get operation later.

    This function is asynchronous, and does not return any information. If an error occurs, user_err/2 of the error report module is called and the notification is discarded.

send_trap(Agent,Trap,Community)
send_trap(Agent,Trap,Community,Varbinds) -> void()

    Types
        Agent = pid() | atom()
        Trap = atom()
        Community = string()
        Varbinds = [Varbind]
        Varbind = {Variable, Value} | {Column, RowIndex, Value} | {OID, Value}
        Variable = atom()
        Column = atom()
        OID = oid()
        Value = term()
        RowIndex = [int()]

    Note! This function is only kept for backwards compatibility reasons. Use send_notification instead.

    Sends the trap Trap to the managers defined for Community in the intTrapDestTable in OTP-SNMPEA-MIB. The optional argument Varbinds defines values for the objects in the trap. If no value is given for an object, the Agent performs a get-operation to retrieve the value.

    Varbinds is a list of Varbind, where each Varbind is one of:

        *   {Variable, Value}, where Variable is the symbolic name of a scalar variable referred to in the trap specification.

        *   {Column, RowIndex, Value}, where Column is the symbolic name of a column variable. RowIndex is a list of indices for the specified element. If this is the case, the OBJECT IDENTIFIER sent in the trap is the RowIndex appended to the OBJECT IDENTIFIER for the table column. This is the OBJECT IDENTIFIER which specifies the element.

        *   {OID, Value}, where OID is the OBJECT IDENTIFIER for an instance of an object, scalar variable, or column variable.

    For example, to specify that sysLocation should have the value "upstairs" in the trap, we could use one of:

        *   {sysLocation, "upstairs"} or

        *   {[1, 3, 6, 1, 2, 1, 1, 6, 0], "upstairs"} or

        *   {?sysLocation_instance, "upstairs"} (provided that the generated .hrl file is included)

    If a variable in the trap is a table element, the RowIndex for the element must be given in the Varbinds list. In this case, the OBJECT IDENTIFIER sent in the trap is the OBJECT IDENTIFIER that identifies this element. This OBJECT IDENTIFIER could be used in a get operation later.

    This function is asynchronous, and does not return any information. If an error occurs, snmp_error:user_err/2 is called and the trap is discarded.

verbosity(Ref,Verbosity) -> void()

    Types
        Ref = pid() | sub_agents | master_agent | net_if | mib_server | symbolic_store | note_store | local_db
        Verbosity = verbosity() | {subagents, verbosity()}
        verbosity() = silence | info | log | debug | trace

    Sets verbosity for the designated process. For the lowest verbosity silence, nothing is printed. The higher the verbosity, the more is printed.

See Also

calendar(3), erlc(1)

AUTHOR
Micael Karlberg - support@erlang.ericsson.se