mtetrigger.c

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                                            _sysUpTime_inst_len );
            netsnmp_query_get(  &sysUT_var, entry->session );

            if (!(entry->flags & MTE_TRIGGER_FLAG_SYSUPT)) {
                /*
                 * ... but only retrieve the configured discontinuity
                 *      marker(s) if they refer to something different.
                 */
                DEBUGMSGTL(( "disman:event:delta",
                             "retrieve discontinuity marker(s): "));
                DEBUGMSGOID(("disman:event:delta", entry->mteDeltaDiscontID,
                                               entry->mteDeltaDiscontID_len ));
                DEBUGMSG((   "disman:event:delta", " %s\n", 
                     (entry->flags & MTE_TRIGGER_FLAG_DWILD ? " (wild)" : "")));

                dvar = (netsnmp_variable_list *)
                                SNMP_MALLOC_TYPEDEF( netsnmp_variable_list );
                if (!dvar) {
                    _mteTrigger_failure(
                            "failed to create mteTrigger delta query varbind");
                    return;
                }
                snmp_set_var_objid( dvar, entry->mteDeltaDiscontID,
                                          entry->mteDeltaDiscontID_len );
                if ( entry->flags & MTE_TRIGGER_FLAG_DWILD ) {
                    netsnmp_query_walk( dvar, entry->session );
                } else {
                    netsnmp_query_get(  dvar, entry->session );
                }
                if ( n != SNMP_ERR_NOERROR ) {
                    _mteTrigger_failure( "failed to run mteTrigger delta query" );
                    snmp_free_varbind( dvar );
                    return;
                }
            }

            /*
             * We can't calculate delta values the first time through,
             *  so there's no point in evaluating the remaining tests.
             *
             * Save the results (and discontinuity markers),
             *   ready for the next run.
             */
            if ( !entry->old_results ) {
                entry->old_results =  var;
                entry->old_deltaDs = dvar;
                entry->sysUpTime   = *sysUT_var.val.integer;
                return;
            }
            /*
             * If the sysUpTime marker has been reset (or strictly,
             *   has advanced by less than the monitor frequency),
             *  there's no point in trying the remaining tests.
             */

            if (*sysUT_var.val.integer < entry->sysUpTime) {
                DEBUGMSGTL(( "disman:event:delta",
                             "single discontinuity: (sysUT)\n"));
                snmp_free_varbind( entry->old_results );
                snmp_free_varbind( entry->old_deltaDs );
                entry->old_results =  var;
                entry->old_deltaDs = dvar;
                entry->sysUpTime   = *sysUT_var.val.integer;
                return;
            }
            /*
             * Similarly if a separate (non-wildcarded) discontinuity
             *  marker has changed, then there's no
             *  point in trying to evaluate these tests either.
             */
            if (!(entry->flags & MTE_TRIGGER_FLAG_DWILD)  &&
                !(entry->flags & MTE_TRIGGER_FLAG_SYSUPT) &&
                  (!entry->old_deltaDs ||
                   (entry->old_deltaDs->val.integer != dvar->val.integer))) {
                DEBUGMSGTL((  "disman:event:delta", "single discontinuity: ("));
                DEBUGMSGOID(( "disman:event:delta", entry->mteDeltaDiscontID,
                                           entry->mteDeltaDiscontID_len));
                DEBUGMSG((    "disman:event:delta", ")\n"));
                snmp_free_varbind( entry->old_results );
                snmp_free_varbind( entry->old_deltaDs );
                entry->old_results =  var;
                entry->old_deltaDs = dvar;
                entry->sysUpTime   = *sysUT_var.val.integer;
                return;
            }

            /*
             * Ensure that the list of (wildcarded) discontinuity 
             *  markers matches the list of monitored values
             *  (inserting/removing discontinuity varbinds as needed)
             *
             * XXX - An alternative approach would be to use the list
             *    of monitored values (instance subidentifiers) to build
             *    the exact list of delta markers to retrieve earlier.
             */
            if (entry->flags & MTE_TRIGGER_FLAG_DWILD) {
                vp1      =  var;
                vp2      = dvar;
                vp2_prev = NULL;
                n  = entry->mteTriggerValueID_len;
                n2 = entry->mteDeltaDiscontID_len;
                while (vp1) {
                    /*
                     * For each monitored instance, check whether
                     *   there's a matching discontinuity entry.
                     */
                    cmp = snmp_oid_compare(vp1->name+n,  vp1->name_length-n,
                                           vp2->name+n2, vp2->name_length-n2 );
                    if ( cmp < 0 ) {
                        /*
                         * If a discontinuity entry is missing,
                         *   insert a (dummy) varbind.
                         * The corresponding delta calculation will
                         *   fail, but this simplifies the later code.
                         */
                        vtmp = (netsnmp_variable_list *)
                                SNMP_MALLOC_TYPEDEF( netsnmp_variable_list );
                        if (!vtmp) {
                            _mteTrigger_failure(
                                  "failed to create mteTrigger discontinuity varbind");
                            return;
                        }
                        snmp_set_var_objid(vtmp, entry->mteDeltaDiscontID,
                                                 entry->mteDeltaDiscontID_len);
                            /* XXX - append instance subids */
                        vtmp->next_variable     = vp2;
                        vp2_prev->next_variable = vtmp;
                        vp2_prev                = vtmp;
                        vp1 = vp1->next_variable;
                    } else if ( cmp == 0 ) {
                        /*
                         * Matching discontinuity entry -  all OK.
                         */
                        vp2_prev = vp2;
                        vp2      = vp2->next_variable;
                        vp1      = vp1->next_variable;
                    } else {
                        /*
                         * Remove unneeded discontinuity entry
                         */
                        vtmp = vp2;
                        vp2_prev->next_variable = vp2->next_variable;
                        vp2                     = vp2->next_variable;
                        vtmp->next_variable = NULL;
                        snmp_free_varbind( vtmp );
                    }
                }
                /*
                 * XXX - Now need to ensure that the old list of
                 *   delta discontinuity markers matches as well.
                 */
            }
        } /* delta samples */
    } /* Boolean/Threshold test checks */



    /*
     * Only run the Boolean tests if there's an event to be triggered
     */
    if ((entry->mteTriggerTest & MTE_TRIGGER_BOOLEAN) &&
        (entry->mteTBoolEvent[0] != '\0' )) {

        if (entry->flags & MTE_TRIGGER_FLAG_DELTA) {
            vp2 = entry->old_results;
            if (entry->flags & MTE_TRIGGER_FLAG_DWILD) {
                dv1 = dvar;
                dv2 = entry->old_deltaDs;
            }
        }
        for ( vp1 = var; vp1; vp1=vp1->next_variable ) {
            /*
             * Determine the value to be monitored...
             */
            if ( !vp1->val.integer ) {  /* No value */
                if ( vp2 )
                    vp2 = vp2->next_variable;
                continue;
            }
            if (entry->flags & MTE_TRIGGER_FLAG_DELTA) {
                if (entry->flags & MTE_TRIGGER_FLAG_DWILD) {
                    /*
                     * We've already checked any non-wildcarded
                     *   discontinuity markers (inc. sysUpTime.0).
                     * Validate this particular sample against
                     *   the relevant wildcarded marker...
                     */
                    if ((dv1->type == ASN_NULL)  ||
                        (dv1->type != dv2->type) ||
                        (*dv1->val.integer != *dv2->val.integer)) {
                        /*
                         * Bogus or changed discontinuity marker.
                         * Need to skip this sample.
                         */
    DEBUGMSGTL(( "disman:event:delta", "discontinuity occurred: "));
    DEBUGMSGOID(("disman:event:delta", vp1->name,
                                       vp1->name_length ));
    DEBUGMSG((   "disman:event:delta", " \n" ));
                        vp2 = vp2->next_variable;
                        continue;
                    }
                }
                /*
                 * ... and check there is a previous sample to calculate
                 *   the delta value against (regardless of whether the
                 *   discontinuity marker was wildcarded or not).
                 */
                if (vp2->type == ASN_NULL) {
    DEBUGMSGTL(( "disman:event:delta", "missing sample: "));
    DEBUGMSGOID(("disman:event:delta", vp1->name,
                                       vp1->name_length ));
    DEBUGMSG((   "disman:event:delta", " \n" ));
                    vp2 = vp2->next_variable;
                    continue;
                }
                value = (*vp1->val.integer - *vp2->val.integer);
    DEBUGMSGTL(( "disman:event:delta", "delta sample: "));
    DEBUGMSGOID(("disman:event:delta", vp1->name,
                                       vp1->name_length ));
    DEBUGMSG((   "disman:event:delta", " (%d - %d) = %d\n",
                *vp1->val.integer,  *vp2->val.integer, value));
                vp2 = vp2->next_variable;
            } else {
                value = *vp1->val.integer;
            }

            /*
             * ... evaluate the comparison ...
             */
            switch (entry->mteTBoolComparison) {
            case MTE_BOOL_UNEQUAL:
                cmp = ( value != entry->mteTBoolValue );
                break;
            case MTE_BOOL_EQUAL:
                cmp = ( value == entry->mteTBoolValue );
                break;
            case MTE_BOOL_LESS:
                cmp = ( value <  entry->mteTBoolValue );
                break;
            case MTE_BOOL_LESSEQUAL:
                cmp = ( value <= entry->mteTBoolValue );
                break;
            case MTE_BOOL_GREATER:
                cmp = ( value >  entry->mteTBoolValue );
                break;
            case MTE_BOOL_GREATEREQUAL:
                cmp = ( value >= entry->mteTBoolValue );
                break;
            }
    DEBUGMSGTL(( "disman:event:delta", "Bool comparison: (%d %s %d) %d\n",
                          value, _ops[entry->mteTBoolComparison],
                          entry->mteTBoolValue, cmp));

            /*
             * ... and decide whether to trigger the event.
             *    (using the 'index' field of the varbind structure
             *     to remember whether the trigger has already fired)
             */
            if ( cmp ) {
                if ((entry->old_results ||
                     (entry->flags & MTE_TRIGGER_FLAG_BSTART)) &&
                    (vp1->index & MTE_ARMED_BOOLEAN )) {
                    DEBUGMSGTL(( "disman:event:trigger:fire",
                                 "Firing boolean test: "));
                    DEBUGMSGOID(("disman:event:trigger:fire",
                                 vp1->name, vp1->name_length));
                    DEBUGMSG((   "disman:event:trigger:fire", "%s\n",
                                  (entry->old_results ? "" : " (startup)")));
                    vp1->index &= ~MTE_ARMED_BOOLEAN;
                    entry->mteTriggerXOwner   = entry->mteTBoolObjOwner;
                    entry->mteTriggerXObjects = entry->mteTBoolObjects;
                    /*
                     * XXX - when firing a delta-based trigger, should
                     *   'mteHotValue' report the actual value sampled
                     *   (as here), or the delta that triggered the event ?
                     */
                    entry->mteTriggerFired    = vp1;
                    n = entry->mteTriggerValueID_len;
                    mteEvent_fire(entry->mteTBoolEvOwner, entry->mteTBoolEvent, 
                                  entry, vp1->name+n, vp1->name_length-n);
                }
            } else {
                vp1->index |= MTE_ARMED_BOOLEAN;
            }
        }
    }


    /*
     * Only run the basic threshold tests if there's an event to
     *    be triggered.  (Either rising or falling will do)
     */
    if (( entry->mteTriggerTest & MTE_TRIGGER_THRESHOLD ) &&