Generating Traps in demo_module_4

The refreshLoadAvg() function is called at regular intervals to refresh data. Immediately after data is refreshed, the refreshLoadAvg() function checks for trap conditions by calling the following functions:

• check_loadavg1_state()

• check_loadavg5_state()

• check_loadavg15_state()

In me4LoadGroup.c, a module property could be in one of two states: OK or ERROR. When the current data value crosses the threshold, the state is set to ERROR. A trap is then generated. The check functions have the following algorithm:

check_loadavg1_state() {

	// Step-1: check condition
	if (currentData > threshold_loadavg1) new_loadavg1_state = ERROR;

	// Step-2: Generate trap if necessary
        if (new_loadavg1_state > prev_loadavg1_state) {
                // Send trap
                prev_loadavg1_state=new_loadavg1_state;
        } else if(new_loadavg1_state == prev_loadavg1_state) {
                /* No Change in state .. Do nothing */
        } else if (new_loadavg1_state < prev_loadavg1_state) {
                if (new_loadavg1_state == OK) {
                        prev_loadavg1_state=OK;
			// Send OK trap
                }
        }
}

When the check indicates that the threshold has been crossed, the send_v2trap function is used to generate an SNMPv2 trap. The trap OID and the varbinds are as specified in the SDK-DEMO4-MIB.txt MIB. For more information on SNMP trap APIs, see /usr/sfw/doc/sma_snmp/html/group__agent__trap.html.