24. Snmp Class Examples

In addition to the examples in this section, please refer to the files in the table below for complete programs which can be used as useful command line utilities.

Program Name and Description	File Name
SnmpGet, performs SNMP++ get to v1 and v2 agents.	snmpget.cpp
SnmpNext, peforms SNMP++ getNext to v1 and v2 agents.	snmpnext.cpp
SnmpBulk, performs SNMP++ getBulk to v1 and v2 agents.	snmpbulk.cpp
SnmpSet, performs SNMP++ set to v1 and v2 agents.	snmpset.cpp
SnmpTrap, sends v1 or v2 trap to a manager.	snmptrap.cpp
SnmpWalk, walks an agent's MIB using v1 or v2 via GetBulk.	snmpwalk.cpp

24.1. Getting a Single MIB Variable Example

#include “snmp_pp.h”

#define SYSDESCR “1.3.6.1.2.1.1.1.0” // Object ID for System Descriptor

void get_system_descriptor()

{

int status; // return status

CTarget ctarget( (IpAddress) “10.4.8.5”); // SNMP++ v1 target

Vb vb( SYSDESCR); // SNMP++ Variable Binding

Pdu pdu; // SNMP++ PDU

//-------[ Construct a SNMP++ SNMP Object ]---------------------------------------

Snmp snmp( status); // Create a SNMP++ session

if ( status != SNMP_CLASS_SUCCESS) { // check creation status

cout << snmp.error_msg( status); // if fail, print error string

return; }

//-------[ Invoke a SNMP++ Get ]-------------------------------------------------------

pdu += vb; // add the variable binding

if ( (status = snmp.get( pdu, ctarget)) != SNMP_CLASS_SUCCESS)

cout << snmp.error_msg( status);

else {

pdu.get_vb( vb,0); // extract the variable binding

cout << “System Descriptor = ”<< vb.get_printable_value(); } // print out

};

24.2. Getting Multiple MIB Variables Example

#include “snmp_pp.h”

#define SYSDESCR “1.3.6.1.2.1.1.1.0” // Object ID for system descriptor

#define SYSOBJECTID "1.3.6.1.2.1.1.2.0" // Object ID for system object ID

#define SYSUPTIME "1.3.6.1.2.1.1.3.0" // Object ID for system up time

#define SYSCONTACT "1.3.6.1.2.1.1.4.0" // Object ID for system contact

#define SYSNAME "1.3.6.1.2.1.1.5.0" // Object ID for system name

#define SYSLOCATION "1.3.6.1.2.1.1.6.0" // Object ID for system location

#define SYSSERVICES "1.3.6.1.2.1.1.7.0" // Object ID for system services

void get_system_group()

{

int status; // return status

CTarget ctarget( (IpAddress) “10.4.8.5”); // SNMP++ v1 target

Vb vb[7]; // a vb for each object to get

Pdu pdu; // SNMP++ PDU

//-------[ Construct a SNMP++ SNMP Object ]---------------------------------------

Snmp snmp( status); // Create a SNMP++ session

if ( status != SNMP_CLASS_SUCCESS) { // check creation status

cout << snmp.error_msg( status); // if fail, print error string

return; }

//-------[ build up the vbs to get]-----------------------------------------------------------------

vb[0].set_oid( SYSDESCR);

vb[1].set_oid( SYSOBJECTID);

vb[2].set_oid( SYSUPTIME);

vb[3].set_oid(SYSCONTACT);

vb[4].set_oid( SYSNAME);

vb[5].set_oid( SYSLOCATION);

vb[6].set_oid( SYSSERVICES);

//----[ append all the vbs to the pdu ]-----------------------------------------------------

for ( int z=0;z<7;z++)

pdu += vb[z];

//-------[ Invoke a SNMP++ Get ]-------------------------------------------------------

if ( (status = snmp.get( pdu, ctarget)) != SNMP_CLASS_SUCCESS)

cout << snmp.error_msg( status);

else {

pdu.get_vbs( vb,7); // extract the variable bindings

for ( int w=0;w<7;w++)

cout << vb[w].get_printable_value() << “\n”; } // print out the value

};

24.3. Setting a Single MIB Variable Example

#include “snmp_pp.h”

#define SYSLOCATION “1.3.6.1.2.1.1.6.0” // Object ID for System location

void set_system_location()

{

int status; // return status

CTarget ctarget( (IpAddress) “10.4.8.5”); // SNMP++ v1 target

Vb vb( SYSLOCATION); // SNMP++ Variable Binding

Pdu pdu; // SNMP++ PDU

//-------[ Construct a SNMP++ SNMP Object ]---------------------------------------

Snmp snmp( status); // Create a SNMP++ session

if ( status != SNMP_CLASS_SUCCESS) { // check creation status

cout << snmp.error_msg( status); // if fail, print error string

return;

}

//-------[ Invoke a SNMP++ Set ]-------------------------------------------------------

vb.set_value(“Upstairs Mezzanine”); // add location string to vb

pdu += vb; // add the variable binding

status = snmp.set( pdu, ctarget);

cout << snmp.error_msg(status);

}

24.4. Setting Multiple MIB Variables Example

#include “snmp_pp.h”

#define SYSCONTACT "1.3.6.1.2.1.1.4.0" // Object ID for system contact

#define SYSNAME "1.3.6.1.2.1.1.5.0" // Object ID for system name

#define SYSLOCATION "1.3.6.1.2.1.1.6.0" // Object ID for system location

void multi_set()

{

int status; // return status

CTarget ctarget( (IpAddress) “10.4.8.5”); // SNMP++ v1 target

Vb vb[3]; // a vb for each object to get

Pdu pdu; // SNMP++ PDU

//-------[ Construct a SNMP++ SNMP Object ]---------------------------------------

Snmp snmp( status); // Create a SNMP++ session

if ( status != SNMP_CLASS_SUCCESS) { // check creation status

cout << snmp.error_msg( status); // if fail, print error string

return; }

//-------[ build up the vbs to get]-----------------------------------------------------------------

vb[0].set_oid( SYSCONTACT);

vb[0].set_value(“Alan Turing”);

vb[1].set_oid( SYSNAME);

vb[1].set_value(“ The Turing Machine”);

vb[2].set_oid( SYSLOCATION );

vb[2].set_value(“ Cambridge, UK”);

//----[ append all the vbs to the pdu ]-----------------------------------------------------

for ( int z=0;z<3;z++)

pdu += vb[z];

//-------[ Invoke a SNMP++ Set ]-------------------------------------------------------

status = snmp.set( pdu, ctarget);

cout << snmp.error_msg( status);

}

24.5. Walking a MIB using Get-Next Example

#include “snmp_pp.h” // include snmp++ header file

void mib_walk()

{

int status; // return status

CTarget target( (IpAddress) “10.4.8.5”); // SNMP++ v1 target

Vb vb; // a SNMP++ vb

Pdu pdu; // SNMP++ PDU

//-------[ Construct a SNMP++ SNMP Object ]---------------------------------------

Snmp snmp( status); // Create a SNMP++ session

if ( status != SNMP_CLASS_SUCCESS) { // check creation status

cout << snmp.error_msg( status); // if fail, print error string

return; }

//-------[ set up the first vb ]---------------------------------------------------------------

vb.set_oid(“1”); // get next starting seed

pdu += vb; // add vb to the pdu

status = SNMP_CLASS_SUCCESS;

while ( status == SNMP_CLASS_SUCCESS)

{

if ( (status = snmp.get_next( pdu, ctarget)) == SNMP_CLASS_SUCCESS) {

pdu.get_vb( vb,0); // extract the vb

cout << “Mib Object = “ << vb.get_printable_oid() << “\n”;

cout << “Mib Value = “ << vb.get_printable_value() << “\n”;

pdu.set_vb( vb,0); // use last vb as the next one

}

else

cout << “SNMP++ Error = “ << snmp.error_msg( status);

}

};

24.6. Sending a Trap Example

#include “snmp_pp.h”

void send_trap()

{

int status; // return status

CTarget target( (IpAddress) “10.4.8.5”); // SNMP++ v1 target

Pdu pdu; // SNMP++ PDU

//-------[ Construct a SNMP++ SNMP Object ]---------------------------------------

Snmp snmp( status); // Create a SNMP++ session

if ( status != SNMP_CLASS_SUCCESS) { // check creation status

cout << snmp.error_msg( status); // if fail, print error string

return; }

status = snmp.trap( pdu, target,coldStart);

cout << “ Trap Send Status = “ << snmp.error_msg( status);

};

24.7. Receiving Traps Example

#include “snmp_pp.h”

//-----------------[ trap callback function definition ]-------------------------------------------------------------------

void my_trap_callback ( int reason, // reason

Snmp* session, // session handle

Pdu & pdu, // trap pdu

TimeTicks &timestamp, // timestamp

SnmpTarget &target, // source of the trap

void * cbd) // optional callback data

{

Address *address;

unsigned char get_cummunity[80], set_community[80];

unsigned long timeout;

int retry;

if ( reason == SNMP_CLASS_TRAP) {

target.resolve_to_C( get_community, // get community

set_community, // set community

&address, // address object

timeout, // timeout

retry); // retry

cout << “Trap Received from << address->get_printable() << “Trap Id = “ << trapid.get_printable();

}

else

cout << “Trap Receive Error = “ << session->error_msg( reason);

};

//---------------[ trap receive register ]---------------------------------------------------------------------

Snmp *snmp; // dynamic Snmp object

void trap_register()

{

//----------------[ instantiate an Snmp object, delete when no longer receiving traps ]------------

int status;

snmp = new Snmp( status);

if (( snmp == NULL) || ( status != SNMP_CLASS_SUCCESS))

cout << “Error constructing Snmp Object\n”;

else

{

//-------[ set up two empty collections, empty denotes receive all ]-------------------------------

TargetCollection targets;

OidCollection trapids;

//------[ invoke the regsiter ]----------------------------------------------------------------------------

if ( status = snmp->notify_register( trapids, targets, & my_trap_callback)) != SNMP_CLASS_SUCCESS)

cout << “ Snmp Trap Register Error “ << snmp->error_msg( status);

}

};