Classes
class	OID
	Wrapper for net-snmp's OID arrays. More...

class	PDU
	Wrapper for net-snmp's PDU structures. More...

class	Varlist
	Wrapper for net-snmp's snmp_variable_list pointer. More...

Typedefs
typedef std::map< SNMPpp::OID, netsnmp_variable_list * >	MapOidVarList
	A std::map where the OID is the key and the value is a net-snmp variable list. This is used by SNMPpp::PDU and SNMPpp::Varlist. More...

typedef void *	SessionHandle
	net-snmp uses a void * for the "Single API" opaque session pointer, but SNMPpp prefers to have an actual named type to make it more obvious when passing the session pointer by reference in C++. More...

typedef std::set< OID >	SetOID
	A std::set of OIDs. More...

typedef std::vector< OID >	VecOID
	A std::vector of OIDs. More...

Functions
long	centisecondsNetSnmpUptime (void)
	Return the uptime in centiseconds. More...

long	centisecondsPidStarted (pid_t pid=0)
	Return the uptime in centiseconds. More...

long	centisecondsSince (const time_t t)
	Return the time since `t`. More...

long	centisecondsUptime (void)
	Return the number of centiseconds since the last reboot. More...

void	closeSession (SessionHandle &sessionHandle)
	Sessions must be closed when no longer needed. More...

SNMPpp::Varlist	createV2TrapVarlist (const SNMPpp::OID &o, const long uptime=SNMPpp::centisecondsNetSnmpUptime())
	Initialize a varlist to be eventually used with one of the sendV2Trap() functions. More...

SNMPpp::PDU	get (SNMPpp::SessionHandle &session, SNMPpp::PDU &pdu)
	Alias to SNMPpp::sync() for convenience, and to be consistent with the various other SNMPpp::get...() calls. More...

SNMPpp::PDU	get (SNMPpp::SessionHandle &session, const SNMPpp::OID &o)
	Get a single OID. More...

SNMPpp::PDU	get (SNMPpp::SessionHandle &session, const SetOID &oids)
	Get several specific OIDs at once. More...

SNMPpp::PDU	getBulk (SNMPpp::SessionHandle &session, const SNMPpp::OID &o, const int maxRepetitions=50, const int nonRepeaters=0)
	Getbulk request, starting with the given OID. More...

SNMPpp::PDU	getBulk (SNMPpp::SessionHandle &session, SNMPpp::PDU &pdu, const int maxRepetitions=50, const int nonRepeaters=0)
	Getbulk request, possibly with multiple starting points. More...

SNMPpp::PDU	getNext (SNMPpp::SessionHandle &session, const SNMPpp::OID &o)
	Get the next OID. More...

SNMPpp::PDU	getNext (SNMPpp::SessionHandle &session, SNMPpp::PDU &request)
	Get the next OID. More...

void	initializeNetSnmpAgent (const std::string &name="snmppp")
	Initialize net-snmp AgentX. More...

void	netsnmpDisableLogging (void)
	Disable net-snmp logging. More...

void	netsnmpLogStdErr (const bool enabled=true)
	Toggle net-snmp logging to STDERR. More...

void	netsnmpLogSyslog (const bool enabled=true)
	Toggle net-snmp logging to syslog. More...

void	netsnmpLogToFile (const bool enabled=true, const std::string &filename="/var/log/netsnmp.log")
	Toggle net-snmp logging to an external file. More...

void	openSession (SessionHandle &sessionHandle, const std::string &server="udp:127.0.0.1:161", const std::string &community="public", const int version=SNMP_VERSION_2c, const int retryAttempts=3)
	Open a net-snmp session and return a session handle. More...

void	sendV2Trap (const SNMPpp::OID &o, const long uptime=SNMPpp::centisecondsNetSnmpUptime())
	Send a SNMPv2 trap to all configured trapsinks in net-snmp. More...

void	sendV2Trap (SNMPpp::Varlist &varlist)
	Send a SNMPv2 trap to alll configured trapsinks in net-snmp. More...

void	sendV2Trap (SNMPpp::PDU &pdu)
	Similar to SNMPpp::sendV2Trap( SNMPpp::Varlist &vl ). More...

void	shutdownNetSnmpAgent (const std::string &name="snmppp")
	De-initialize net-snmp AgentX. More...

SNMPpp::PDU	sync (SNMPpp::SessionHandle &session, SNMPpp::PDU &request)
	Send a PDU using the given SNMPpp::SessionHandle, and wait for a reply. More...

std::string	version (void)
	Return the SNMPpp version number. More...

Typedef Documentation

typedef std::map< SNMPpp::OID, netsnmp_variable_list *> SNMPpp::MapOidVarList

A std::map where the OID is the key and the value is a net-snmp variable list. This is used by SNMPpp::PDU and SNMPpp::Varlist.

typedef void* SNMPpp::SessionHandle

net-snmp uses a void * for the "Single API" opaque session pointer, but SNMPpp prefers to have an actual named type to make it more obvious when passing the session pointer by reference in C++.

For example, see the return value of snmp_sess_open();.

See Also: SNMPpp::openSession();; SNMPpp::closeSession();

typedef std::set<OID> SNMPpp::SetOID

A std::set of OIDs.

typedef std::vector<OID> SNMPpp::VecOID

A std::vector of OIDs.

Function Documentation

long SNMPpp::centisecondsNetSnmpUptime ( void )

Return the uptime in centiseconds.

Note: On linux, this seems to be just a few centiseconds off from the last reboot, and it is unaffected by restarting snmpd. If you don't know which one of the SNMPpp::centiseconds...() call you need to use, this is most likely the safest and best choice.

The first variable in SNMPv2 traps is 'sysUpTime', which is defined as:

 "the time ... since the network management portion of the system was re-initialized"

But in all likelihood, this value isn't easily available from code which is using SNMPpp. So several other possibly useful values have been made available for convenience. Of those, centisecondsNetSnmpUptime() is most likely the value you need to use.

Todo:: What does netsnmp_get_agent_uptime(); return? I tried both get_uptime() and netsnmp_get_agent_uptime() but as far as I can tell the one called netsnmp_get_agent_uptime() returns garbage.

Returns: net-snmp's get_uptime(), which on linux seems to be the number of centiseconds since the system was rebooted.

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long SNMPpp::centisecondsPidStarted ( pid_t pid = 0)

Return the uptime in centiseconds.

Parameters

[in] pid If set to zero then the current process ID will be queried by calling getpid().

Todo:: Not supported in Windows; returns centisecondsUptime() instead.

Returns: If the pid uptime is unavailable or cannot be found, then SNMPpp::centisecondsNetSnmpUptime() is returned instead.; If the pid uptime was determined, return the number of centiseconds (1/100s) since the given PID was started.

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long SNMPpp::centisecondsSince ( const time_t t)

Return the time since t.

Returns: the number of centiseconds (1/100s) that have elapsed since the given time. If the specified time is in the future, then zero is returned.

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long SNMPpp::centisecondsUptime ( void )

Return the number of centiseconds since the last reboot.

Todo:: In Windows, GetTickCount() wraps after 7 weeks. Look into using something else, such as GetTickCount64().

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void SNMPpp::closeSession ( SNMPpp::SessionHandle & sessionHandle)

Sessions must be closed when no longer needed.

This can be done by calling snmp_sess_close() directly, or SNMPpp::closeSession().

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SNMPpp::Varlist SNMPpp::createV2TrapVarlist	(	const SNMPpp::OID &	o,
		const long	uptime = `SNMPpp::centisecondsNetSnmpUptime()`
	)

Initialize a varlist to be eventually used with one of the sendV2Trap() functions.

If you'd like to send a trap with multiple variables, you can use this method as a starting point to easily create a varlist with the first two OIDs filled in correctly. Once you finish adding variables to the varlist, call SNMPpp::sendV2Trap( SNMPpp::Varlist &vl ) to have the trap sent out.

Exceptions

std::invalid_argument if the OID is empty.

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SNMPpp::PDU SNMPpp::get	(	SNMPpp::SessionHandle &	session,
		SNMPpp::PDU &	pdu
	)

Alias to SNMPpp::sync() for convenience, and to be consistent with the various other SNMPpp::get...() calls.

See Also: SNMPpp::sync() to see additional exceptions this may throw.

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SNMPpp::PDU SNMPpp::get	(	SNMPpp::SessionHandle &	session,
		const SNMPpp::OID &	o
	)

Get a single OID.

Note

The response PDU needs to be freed using SNMPpp::PDU::free().
This will throw if an unexpected problem occurs.

See Also: SNMPpp::sync() to see additional exceptions this may throw.

Exceptions

std::invalid_argument if the OID is empty.

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SNMPpp::PDU SNMPpp::get	(	SNMPpp::SessionHandle &	session,
		const SetOID &	oids
	)

Get several specific OIDs at once.

Note

The response PDU needs to be freed using SNMPpp::PDU::free().
This will throw if an unexpected problem occurs.

See Also: SNMPpp::sync() to see additional exceptions this may throw.

Exceptions

std::invalid_argument if the SetOID is empty.

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SNMPpp::PDU SNMPpp::getBulk	(	SNMPpp::SessionHandle &	session,
		const SNMPpp::OID &	o,
		const int	maxRepetitions = `50`,
		const int	nonRepeaters = `0`
	)

Getbulk request, starting with the given OID.

Note

Getbulk requests require SNMPv2 or higher on the server.
The response PDU needs to be freed using SNMPpp::PDU::free().
This will throw if an unexpected problem occurs.

See Also: SNMPpp::sync() to see additional exceptions this may throw.

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SNMPpp::PDU SNMPpp::getBulk	(	SNMPpp::SessionHandle &	session,
		SNMPpp::PDU &	pdu,
		const int	maxRepetitions = `50`,
		const int	nonRepeaters = `0`
	)

Getbulk request, possibly with multiple starting points.

Note

Getbulk requests require SNMPv2 or higher on the server.
The request PDU is automatically freed before returning to the caller, even when an exception is thrown.
The response PDU needs to be freed using SNMPpp::PDU::free().
This will throw if an unexpected problem occurs.

See Also: SNMPpp::sync() to see additional exceptions this may throw.

Exceptions

std::invalid_argument if the PDU is empty.

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SNMPpp::PDU SNMPpp::getNext	(	SNMPpp::SessionHandle &	session,
		const SNMPpp::OID &	o
	)

Get the next OID.

Note

The response PDU needs to be freed using SNMPpp::PDU::free().
This will throw if an unexpected problem occurs.

See Also: SNMPpp::sync() to see additional exceptions this may throw.

Exceptions

std::invalid_argument if the OID is empty.

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SNMPpp::PDU SNMPpp::getNext	(	SNMPpp::SessionHandle &	session,
		SNMPpp::PDU &	request
	)

Get the next OID.

Note

The request PDU is automatically freed before returning to the caller, even when an exception is thrown.
The response PDU needs to be freed using SNMPpp::PDU::free().
This will throw if an unexpected problem occurs.

See Also: SNMPpp::sync() to see additional exceptions this may throw.

Exceptions

std::invalid_argument if the PDU is empty.

If the PDU is already of type SNMPpp::PDU::kGetNext then it is sent unchanged to the server described in SNMPpp::SessionHandle. But if the PDU is of any other type – such as a response PDU – then we'll look through the varlist and take the last OID listed. Using this, a response PDU can quickly be re-used to get the next OID from a SNMP server.

For example, note how the output PDU is then re-used as input in this simple while loop:

pdu.clear();
pdu.addNullVar( ".1" );
while ( true )
{
    pdu = SNMPpp::getNext( sessionHandle, pdu );
    if ( ... )
}

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void SNMPpp::initializeNetSnmpAgent ( const std::string & name = "snmppp")

Initialize net-snmp AgentX.

Exceptions

std::runtime_error if net-snmp init_agent(name) returned an error.

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void SNMPpp::netsnmpDisableLogging ( void )

Disable net-snmp logging.

See Also: net-snmp/library/snmp_logging.h for several more options.

void SNMPpp::netsnmpLogStdErr ( const bool enabled = true)

Toggle net-snmp logging to STDERR.

Todo:: Why is init_snmp_logging() an unresolved external in Windows?

void SNMPpp::netsnmpLogSyslog ( const bool enabled = true)

Toggle net-snmp logging to syslog.

Todo:: Why is init_snmp_logging() an unresolved external in Windows?

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void SNMPpp::netsnmpLogToFile	(	const bool	enabled = `true`,
		const std::string &	filename = `"/var/log/netsnmp.log"`
	)

Toggle net-snmp logging to an external file.

Note: net-snmp may not be running as "root", and may not have access to the file it is being told to use to log. Check your directory and file write permissions if the log file you expect wasn't created.

Todo:: Why is init_snmp_logging() an unresolved external in Windows?

Todo:: Why is snmp_disable_filelog() an unresolved external in Windows?

void SNMPpp::openSession	(	SNMPpp::SessionHandle &	sessionHandle,
		const std::string &	server = `"udp:127.0.0.1:161"`,
		const std::string &	community = `"public"`,
		const int	version = `SNMP_VERSION_2c`,
		const int	retryAttempts = `3`
	)

Open a net-snmp session and return a session handle.

The session handle will be needed for all other net-snmp calls. Any previous value in "handle" will be blindly overwritten, so don't re-use handles unless you've remembered to call either snmp_sess_close() or SNMPpp::closeSession().

Note

Handles must be freed when no longer needed.
Handles are not the same as struct snmp_session!
This will throw if something goes wrong when setting up the session.

Exceptions

std::runtime_error if snmp_sess_open() fails to return a valid new session.

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void SNMPpp::sendV2Trap	(	const SNMPpp::OID &	o,
		const long	uptime = `SNMPpp::centisecondsNetSnmpUptime()`
	)

Send a SNMPv2 trap to all configured trapsinks in net-snmp.

Note: To send a trap, it seems an application must have made the right calls to be considered a net-snmp agent. If you want to generate traps from an application which isn't running as an agent, remember to call SNMPpp::initializeNetSnmpAgent() otherwise no trap will be sent.

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void SNMPpp::sendV2Trap ( SNMPpp::Varlist & varlist)

Send a SNMPv2 trap to alll configured trapsinks in net-snmp.

If you have a variable list already made up with at least 2 entries describing the uptime and the trap, call this function. Note you can use this to send as many additional OIDs as you want with the trap. The variable list is freed prior to returning to the caller.

See Also: SNMPpp::createV2TrapVarlist();

Exceptions

std::invalid_argument	if varlist is empty.
std::invalid_argument	if the varlist contains less than 2 OIDs.
std::runtime_error	if netsnmp_send_traps(...) returned an error.

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void SNMPpp::sendV2Trap ( SNMPpp::PDU & pdu)

The PDU is freed prior to returning to the caller.

Exceptions

std::invalid_argument if the PDU is empty.

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void SNMPpp::shutdownNetSnmpAgent ( const std::string & name = "snmppp")

De-initialize net-snmp AgentX.

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SNMPpp::PDU SNMPpp::sync	(	SNMPpp::SessionHandle &	session,
		SNMPpp::PDU &	request
	)

Send a PDU using the given SNMPpp::SessionHandle, and wait for a reply.

This is the method all other "get" functions call to perform the underlying request->response sync with the SNMP server.

Note

The request PDU is automatically freed before returning to the caller, even when an exception is thrown.
The response PDU needs to be freed using SNMPpp::PDU::free().
This will throw if an unexpected problem occurs.

Exceptions

std::invalid_argument	if the PDU is empty.
std::invalid_argument	if the session handle is NULL.
std::runtime_error	if snmp_sess_synch_response() returned an error.

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std::string SNMPpp::version ( void )

Return the SNMPpp version number.

See Also: LIBSNMPPPVER.

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Classes

Typedefs

Functions

Typedef Documentation

Function Documentation