snmpa
Module
snmpa
Module Summary
Interface Functions to the SNMP toolkit agent
Description
The module snmpa
contains interface functions to the SNMP agent.
Data types
oid() = [byte()] atl_type() = read | write | read_write notification_delivery_info() = #snmpa_notification_delivery_info{}
The oid()
type is used to represent an ASN.1 OBJECT IDENTIFIER.
The record snmpa_notification_delivery_info
contains the following fields:
tag = term()
-
A user defined identity representing this notification send operation.
mod = module()
-
A module implementing the
snmpa_notification_delivery_info_receiver
behaviour. The info functions of this module will be called at various stages of delivery. extra = term()
-
This is any extra info the user wants to have supplied when the functions in the callback module is called.
Exports
add_agent_caps(SysORID, SysORDescr) -> SysORIndex
Types
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
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
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
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 current_request_id
) 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
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.
backup(BackupDir) -> ok | {error, Reason}
backup(Agent, BackupDir) -> ok | {error, Reason}
Types
Backup persistent/permanent data handled by the agent (such as local-db, mib-data and vacm).
Data stored by mnesia is not handled.
BackupDir cannot be identical to DbDir.
Simultaneous backup calls are not allowed. That is, two different processes cannot simultaneously successfully call this function. One of them will be first, and succeed. The second will fail with the error reason backup_in_progress
.
info() -> [{Key, Value}]
info(Agent) -> [{Key, Value}]
Types
Returns a list (a dictionary) containing information about the agent. Information includes loaded MIBs, registered sub-agents, some information about the memory allocation.
As of version 4.4 the format of the info has been changed. To convert the info to the old format, call the old_info_format
function.
old_info_format(NewInfo) -> OldInfo
Types
As of version 4.4 the format of the info has been changed. This function is used to convert to the old (pre-4.4) info format.
load_mib(Mib) -> ok | {error, Reason}
load_mib(Agent, Mib) -> ok | {error, Reason}
Types
Load a single Mib
into an agent. 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_mib(snmp_master_agent, Dir ++ "MY-MIB").
load_mibs(Mibs) -> ok | {error, Reason}
load_mibs(Mibs, Force) -> ok | {error, Reason}
load_mibs(Agent, Mibs) -> ok | {error, Reason}
load_mibs(Agent, Mibs, Force) -> ok | {error, Reason}
Types
Load Mibs
into an agent. If the agent cannot load all MIBs (the default value of the Force
argument is false
), 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"]).
If Force = true
then the agent will continue attempting to load each mib even after failing to load a previous mib. Use with care.
unload_mib(Mib) -> ok | {error, Reason}
unload_mib(Agent, Mib) -> ok | {error, Reason}
Types
Unload a single Mib
from an agent.
unload_mibs(Mibs) -> ok | {error, Reason}
unload_mibs(Mibs, Force) -> ok | {error, Reason}
unload_mibs(Agent, Mibs) -> ok | {error, Reason}
unload_mibs(Agent, Mibs, Force) -> ok | {error, Reason}
Types
Unload Mibs
from an agent. If it cannot unload all MIBs (the default value of the Force
argument is false
), it will indicate where unloading was aborted.
If Force = true
then the agent will continue attempting to unload each mib even after failing to unload a previous mib. Use with care.
which_mibs() -> Mibs
which_mibs(Agent) -> Mibs
Types
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
Get the full path to the (compiled) mib-file.
current_request_id() -> {value, RequestId} | false
current_context() -> {value, Context} | false
current_community() -> {value, Community} | false
current_address() -> {value, Address} | false
Types
Get the request-id, context, community and address of the request currently being processed by the agent.
Note that these functions is intended to be called by the instrumentation functions and only if they are executed in the context of the agent process (e.g. it does not work if called from a spawned process).
enum_to_int(Name, Enum) -> {value, Int} | false
enum_to_int(Db, Name, Enum) -> {value, Int} | false
Types
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
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
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
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
Retrieve all alias-names known to the agent.
which_tables() -> Result
Types
Retrieve all tables known to the agent.
which_variables() -> Result
Types
Retrieve all variables known to the agent.
which_notifications() -> Result
Types
Retrieve all notifications (and traps) known to the agent.
log_to_txt(LogDir)
log_to_txt(LogDir, Block | Mibs)
log_to_txt(LogDir, Mibs, Block | OutFile) -> ok | {error, Reason}
log_to_txt(LogDir, Mibs, OutFile, Block | LogName) -> ok | {error, Reason}
log_to_txt(LogDir, Mibs, OutFile, LogName, Block | LogFile) -> ok | {error, Reason}
log_to_txt(LogDir, Mibs, OutFile, LogName, LogFile, Block | Start) -> ok | {error, Reason}
log_to_txt(LogDir, Mibs, OutFile, LogName, LogFile, Block, Start) -> ok | {error, Reason}
log_to_txt(LogDir, Mibs, OutFile, LogName, LogFile, Start, Stop) -> ok | {error, Reason}
log_to_txt(LogDir, Mibs, OutFile, LogName, LogFile, Block, Start, Stop) -> ok | {error, Reason}
Types
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".
The Block
option indicates if the log should be blocked during conversion. This could be usefull when converting large logs (when otherwise the log could wrap during conversion). Defaults to true
.
See snmp:log_to_txt
for more info.
log_to_io(LogDir) -> ok | {error, Reason}
log_to_io(LogDir, Block | Mibs) -> ok | {error, Reason}
log_to_io(LogDir, Mibs, Block | LogName) -> ok | {error, Reason}
log_to_io(LogDir, Mibs, LogName, Block | LogFile) -> ok | {error, Reason}
log_to_io(LogDir, Mibs, LogName, LogFile, Block | Start) -> ok | {error, Reason}
log_to_io(LogDir, Mibs, LogName, LogFile, Block, Start) -> ok | {error, Reason}
log_to_io(LogDir, Mibs, LogName, LogFile, Start, Stop) -> ok | {error, Reason}
log_to_io(LogDir, Mibs, LogName, LogFile, Block, Start, Stop) -> ok | {error, Reason}
Types
Converts an Audit Trail Log to a readable format and prints it on stdio. LogName
defaults to "snmpa_log". LogFile
defaults to "snmpa.log".
The Block
option indicates if the log should be blocked during conversion. This could be usefull when converting large logs (when otherwise the log could wrap during conversion). Defaults to true
.
See snmp:log_to_io
for more info.
change_log_size(NewSize) -> ok | {error, Reason}
Types
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 remembered across reboots.
set_log_type(NewType) -> {ok, OldType} | {error, Reason}
set_log_type(Agent, NewType) -> {ok, OldType} | {error, Reason}
Types
Changes the run-time Audit Trail log type.
Note that this has no effect on the application configuration as defined by configuration files, so a node restart will revert the config to whatever is in those files.
This function is primarily useful in testing/debugging scenarios.
mib_of(Oid) -> {ok, MibName} | {error, Reason}
mib_of(Agent, Oid) -> {ok, MibName} | {error, Reason}
Types
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
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>
invalidate_mibs_cache() -> void()
invalidate_mibs_cache(Agent) -> void()
Types
Invalidate the mib server cache.
The entire contents of the cache will be deleted.
enable_mibs_cache() -> void()
enable_mibs_cache(Agent) -> void()
Types
Enable the mib server cache.
disable_mibs_cache() -> void()
disable_mibs_cache(Agent) -> void()
Types
Disable the mib server cache.
which_mibs_cache_size() -> void()
which_mibs_cache_size(Agent) -> void()
Types
Retreive the size of the mib server cache.
gc_mibs_cache() -> {ok, NumElementsGCed} | {error, Reason}
gc_mibs_cache(Agent) -> {ok, NumElementsGCed} | {error, Reason}
gc_mibs_cache(Age) -> {ok, NumElementsGCed} | {error, Reason}
gc_mibs_cache(Agent, Age) -> {ok, NumElementsGCed} | {error, Reason}
gc_mibs_cache(Age, GcLimit) -> {ok, NumElementsGCed} | {error, Reason}
gc_mibs_cache(Agent, Age, GcLimit) -> {ok, NumElementsGCed} | {error, Reason}
Types
Perform mib server cache gc.
Manually performs a mib server cache gc. This can be done regardless of the value of the autogc
option. The NumElementsGCed
value indicates how many elements where actually removed from the cache.
enable_mibs_cache_autogc() -> void()
enable_mibs_cache_autogc(Agent) -> void()
Types
Enable automatic gc of the mib server cache.
disable_mibs_cache_autogc() -> void()
disable_mibs_cache_autogc(Agent) -> void()
Types
Disable automatic gc of the mib server cache.
update_mibs_cache_age(NewAge) -> ok | {error, Reason}
update_mibs_cache_age(Agent, NewAge) -> ok | {error, Reason}
Types
Change the mib server cache age
property.
update_mibs_cache_gclimit(NewGcLimit) -> ok | {error, Reason}
update_mibs_cache_gclimit(Agent, NewGCLimit) -> ok | {error, Reason}
Types
Change the mib server cache gclimit
property.
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
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
Unregister a notification filter.
which_notification_filter() -> Filters
which_notification_filter(Agent) -> Filters
Types
List all notification filters in an agent.
set_request_limit(NewLimit) -> {ok, OldLimit} | {error, Reason}
set_request_limit(Agent, NewLimit) -> {ok, OldLimit} | {error, Reason}
Types
Changes the request limit.
Note that this has no effect on the application configuration as defined by configuration files, so a node restart will revert the config to whatever is in those files.
This function is primarily useful in load regulation scenarios.
register_subagent(Agent, SubTreeOid, Subagent) -> ok | {error, Reason}
Types
Registers a sub-agent under a sub-tree of another agent.
It is easy to make mistakes when registering sub-agents 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
Unregister a sub-agent. If the second argument is a pid, then that sub-agent will be unregistered from all trees in Agent
.
send_notification2(Agent, Notification, SendOpts) -> void()
Types
Send the notification Notification
to the management targets defined for notify-name (name
) in the snmpNotifyTable
in SNMP-NOTIFICATION-MIB from the specified context
.
If no name
is specified (or if it is ""
), the notification is sent to all management targets.
If no context
is specified, the default context, ""
, is used.
The send option receiver
specifies where information about delivery of Inform-Requests should be sent. The agent sends Inform-Requests and waits for acknowledgments from the management targets. The receiver
can have three values:
-
no_receiver
- No information is delivered. -
notification_delivery_info()
- The information is delivered via a function call according to this data. See theDATA TYPES
section above for details. -
{tag(), tag_receiver()}
- The information is delivered either via messages or via a function call according to the value oftag_receiver()
.Delivery is done differently depending on the value of
tag_receiver()
:-
pid() | registered_name()
- The info will be delivered in the following messages:-
{snmp_targets, tag(), Addresses}
This informs the user which target addresses the notification was sent to.
-
{snmp_notification, tag(), {got_response, Address}}
This informs the user that this target address acknowledged the notification.
-
{snmp_notification, tag(), {no_response, Address}}
This informs the user that this target address did not acknowledge the notification.
The notification is sent as an Inform-Request to each target address in
Addresses
and if there are no targets for which an Inform-Request is sent,Addresses
is the empty list[]
.The
tag_receiver()
will first be sent thesnmp_targets
message, and then for each address inAddresses
list, one of the twosnmp_notification
messages. -
-
{Mod, Func, Args}
- The info will be delivered via the function call:Mod:Func([Msg | Args])
where
Msg
has the same content and purpose as the messages descrived above.
-
The extra
info is not normally interpreted by the agent, instead it is passed through to the net-if
process. It is up to the implementor of that process to make use of this data.
The version of net-if provided by this application makes no use of this data, with one exception: Any tuple containing the atom snmpa_default_notification_extra_info
may be used by the agent and is therefor reserved.
See the net-if incomming messages for sending a trap
and notification
for more info.
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()
send_notification(Agent, Notification, Receiver, NotifyName, ContextName, Varbinds, LocalEngineID) -> void()
Types
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 (Addresses
below).
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 acknowledgments from the managers. Receiver
can have three values:
-
no_receiver
- No information is delivered. -
notification_delivery_info()
- The information is delivered via a function call according to this data. See theDATA TYPES
section above for details. -
{Tag, Recv}
- The information is delivered either via messages or via a function call according to the value ofRecv
.
If Receiver
has the value {Tag, Recv}
, the delivery is done according to Recv
:
-
pid() | atom()
- The info will be delivered in the following messages:-
{snmp_targets, Tag, Addresses}
This inform the user which target addresses the notification was sent to.
-
{snmp_notification, Tag, {got_response, Address}}
This informs the user that this target address acknowledged the notification.
-
{snmp_notification, Tag, {no_response, Address}}
This informs the user that this target address did not acknowledge notification.
The notification is sent as an Inform-Request to each target address in
Addresses
and if there are no targets for which an Inform-Request is sent,Addresses
is the empty list[]
.The
receiver
will first be sent thesnmp_targets
message, and then for each address inAddresses
list, one of the twosnmp_notification
messages. -
-
{Mod, Func, Args}
- The info will be delivered via the function call:Mod:Func([Msg | Args])
where
Msg
has the same content and purpose as the messages descrived above.
Address
is a management target address and Addresses
is a list of management target addresses. They are defined as followes:
Addresses = [address()] Address = address() address() = v1_address() | v3_address() v1_address() = {TDomain, TAddress} v3_address() = {{TDomain, TAddress}, V3MsgData} TDomain = tdoamin() TAddress = taddress() tdomain() = The oid of snmpUDPDomain This is the only supported transport domain. taddress() = [A1, A2, A3, A4, P1, P3] The 4 first bytes makes up the IP-address and the last 2, the UDP-port number. V3MsgData = v3_msg_data() v3_msg_data() = term()
If Receiver
is a notification_delivery_info()
record, then the information about the notification delivery will be delivered to the receiver
via the callback functions defined by the snmpa_notification_delivery_info_receiver
behaviour according to the content of the notification_delivery_info()
record.
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}
, whereVariable
is the symbolic name of a scalar variable referred to in the notification specification. -
{Column, RowIndex, Value}
, whereColumn
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 theRowIndex
appended to the OBJECT IDENTIFIER for the table column. This is the OBJECT IDENTIFIER which specifies the element. -
{OID, Value}
, whereOID
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.
Note that the use of the LocalEngineID argument is only intended for special cases, if the agent is to "emulate" multiple EngineIDs! By default, the agent uses the value of SnmpEngineID
(see SNMP-FRAMEWORK-MIB).
ExtraInfo
is not normally used in any way by the agent. It is intended to be passed along to the net-if process, which is a component that a user can implement themself. The users own net-if may then make use of ExtraInfo. The net-if provided with this application does not process ExtraInfo.
There is one exception. Any tuple containing the atom snmpa_default_notification_extra_info
will, in this context, be considered belonging to this application, and may be processed by the agent.
discovery(TargetName, Notification) -> {ok, ManagerEngineID} | {error, Reason}
discovery(TargetName, Notification, Varbinds) -> {ok, ManagerEngineID} | {error, Reason}
discovery(TargetName, Notification, DiscoHandler) -> {ok, ManagerEngineID} | {error, Reason}
discovery(TargetName, Notification, ContextName, Varbinds) -> {ok, ManagerEngineID} | {error, Reason}
discovery(TargetName, Notification, Varbinds, DiscoHandler) -> {ok, ManagerEngineID} | {error, Reason}
discovery(TargetName, Notification, ContextName, Varbinds, DiscoHandler) -> {ok, ManagerEngineID} | {error, Reason}
discovery(TargetName, Notification, ContextName, Varbinds, DiscoHandler, ExtraInfo) -> {ok, ManagerEngineID} | {error, Reason}
Types
Initiate the discovery process with the manager identified by TargetName
using the notification Notification
.
This function is synchronous, which means that it will return when the discovery process has been completed or failed.
The DiscoHandler
module is used during the discovery process. See discovery handler
for more info.
The ExtraInfo
argument is passed on to the callback functions of the DiscoHandler
.
If we are not at security-level noAuthNoPriv
, this could be complicated, since the agent will then continue with stage 2, before which the usm-related updates must be done.
The default discovery handler will require additional actions by the caller and the discovery will not work if the security-level is higher then noAuthNoPriv
.
convert_config(OldConfig) -> AgentConfig
Types
This off-line utility function can be used to convert the old snmp application config (pre snmp-4.0) to the new snmp agent config (as of snmp-4.0).
For information about the old config (OldConfig
) see the OTP R9C documentation.
For information about the current agent config (AgentConfig
), see either the SNMP application
part of the reference manual or the Configuring the application
chapter of the SNMP user's guide.
restart_worker() -> void()
restart_worker(Agent) -> void()
Types
Restart the worker process of a multi-threaded agent.
This is a utility function, that can be useful when e.g. debugging instrumentation functions.
restart_set_worker() -> void()
restart_set_worker(Agent) -> void()
Types
Restart the set worker process of a multi-threaded agent.
This is a utility function, that can be useful when e.g. debugging instrumentation functions.
print_mib_info() -> void()
Prints the content of all the (snmp) tables and variables for all mibs handled by the snmp agent.
print_mib_tables() -> void()
Prints the content of all the (snmp) tables for all mibs handled by the snmp agent.
print_mib_variables() -> void()
Prints the content of all the (snmp) variables for all mibs handled by the snmp agent.
verbosity(Ref,Verbosity) -> void()
Types
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)
© 2010–2017 Ericsson AB
Licensed under the Apache License, Version 2.0.