mtetrigger.c

开发snmp的开发包有两个开放的SNMP开发库

/*
 * DisMan Event MIB:
 *     Core implementation of the trigger handling behaviour
 */

#include <net-snmp/net-snmp-config.h>
#include <net-snmp/net-snmp-includes.h>
#include <net-snmp/agent/net-snmp-agent-includes.h>
#include "disman/event/mteTrigger.h"
#include "disman/event/mteEvent.h"

netsnmp_tdata *trigger_table_data;

oid    _sysUpTime_instance[] = { 1, 3, 6, 1, 2, 1, 1, 3, 0 };
size_t _sysUpTime_inst_len   = OID_LENGTH(_sysUpTime_instance);

long mteTriggerFailures;

    /*
     * Initialize the container for the (combined) mteTrigger*Table,
     * regardless of which table initialisation routine is called first.
     */

void
init_trigger_table_data(void)
{
    DEBUGMSGTL(("disman:event:init", "init trigger container\n"));
    if (!trigger_table_data) {
        trigger_table_data = netsnmp_tdata_create_table("mteTriggerTable", 0);
        if (!trigger_table_data) {
            snmp_log(LOG_ERR, "failed to create mteTriggerTable");
            return;
        }
        DEBUGMSGTL(("disman:event:init", "create trigger container (%x)\n",
                                          trigger_table_data));
    }
    mteTriggerFailures = 0;
}


/** Initializes the mteTrigger module */
void
init_mteTrigger(void)
{
    init_trigger_table_data();

}

    /* ===================================================
     *
     * APIs for maintaining the contents of the (combined)
     *    mteTrigger*Table container.
     *
     * =================================================== */

void
_mteTrigger_dump(void)
{
    struct mteTrigger *entry;
    netsnmp_tdata_row *row;
    int i = 0;

    for (row = netsnmp_tdata_row_first(trigger_table_data);
         row;
         row = netsnmp_tdata_row_next(trigger_table_data, row)) {
        entry = (struct mteTrigger *)row->data;
        DEBUGMSGTL(("disman:event:dump", "TriggerTable entry %d: ", i));
        DEBUGMSGOID(("disman:event:dump", row->oid_index.oids, row->oid_index.len));
        DEBUGMSG(("disman:event:dump", "(%s, %s)",
                                         row->indexes->val.string,
                                         row->indexes->next_variable->val.string));
        DEBUGMSG(("disman:event:dump", ": %x, %x\n", row, entry));
        i++;
    }
    DEBUGMSGTL(("disman:event:dump", "TriggerTable %d entries\n", i));
}


/*
 * Create a new row in the trigger table 
 */
netsnmp_tdata_row *
mteTrigger_createEntry(char *mteOwner, char *mteTName, int fixed)
{
    struct mteTrigger *entry;
    netsnmp_tdata_row *row;
    size_t mteOwner_len = (mteOwner) ? strlen(mteOwner) : 0;
    size_t mteTName_len = (mteTName) ? strlen(mteTName) : 0;

    DEBUGMSGTL(("disman:event:table", "Create trigger entry (%s, %s)\n",
                                       mteOwner, mteTName));
    /*
     * Create the mteTrigger entry, and the
     * (table-independent) row wrapper structure...
     */
    entry = SNMP_MALLOC_TYPEDEF(struct mteTrigger);
    if (!entry)
        return NULL;

    row = netsnmp_tdata_create_row();
    if (!row) {
        SNMP_FREE(entry);
        return NULL;
    }
    row->data = entry;

    /*
     * ... initialize this row with the indexes supplied
     *     and the default values for the row...
     */
    if (mteOwner)
        memcpy(entry->mteOwner, mteOwner, mteOwner_len);
    netsnmp_table_row_add_index(row, ASN_OCTET_STR,
                                entry->mteOwner, mteOwner_len);
    if (mteTName)
        memcpy(entry->mteTName, mteTName, mteTName_len);
    netsnmp_table_row_add_index(row, ASN_PRIV_IMPLIED_OCTET_STR,
                                entry->mteTName, mteTName_len);

  /* entry->mteTriggerTest         = MTE_TRIGGER_BOOLEAN; */
    entry->mteTriggerValueID_len  = 2;  /* .0.0 */
    entry->mteTriggerFrequency    = 600;
    memcpy(entry->mteDeltaDiscontID, _sysUpTime_instance,
                              sizeof(_sysUpTime_instance));
    entry->mteDeltaDiscontID_len  =  _sysUpTime_inst_len;
    entry->mteDeltaDiscontIDType  = MTE_DELTAD_TTICKS;
    entry->flags                 |= MTE_TRIGGER_FLAG_SYSUPT;
    entry->mteTExTest             = (MTE_EXIST_PRESENT | MTE_EXIST_ABSENT);
    entry->mteTExStartup          = (MTE_EXIST_PRESENT | MTE_EXIST_ABSENT);
    entry->mteTBoolComparison     = MTE_BOOL_UNEQUAL;
    entry->flags                 |= MTE_TRIGGER_FLAG_BSTART;
    entry->mteTThStartup          = MTE_THRESH_START_RISEFALL;

    if (fixed)
        entry->flags |= MTE_TRIGGER_FLAG_FIXED;

    /*
     * ... and insert the row into the (common) table container
     */
    netsnmp_tdata_add_row(trigger_table_data, row);
    DEBUGMSGTL(("disman:event:table", "Trigger entry created\n"));
    return row;
}

/*
 * Remove a row from the trigger table 
 */
void
mteTrigger_removeEntry(netsnmp_tdata_row *row)
{
    struct mteTrigger *entry;

    if (!row)
        return;                 /* Nothing to remove */
    entry = (struct mteTrigger *)
        netsnmp_tdata_remove_and_delete_row(trigger_table_data, row);
    if (entry) {
        mteTrigger_disable( entry );
        SNMP_FREE(entry);
    }
}

    /* ===================================================
     *
     * APIs for evaluating a trigger,
     *   and firing the appropriate event
     *
     * =================================================== */
const char *_ops[] = { "",
                "!=", /* MTE_BOOL_UNEQUAL      */
                "==", /* MTE_BOOL_EQUAL        */
                "<",  /* MTE_BOOL_LESS         */
                "<=", /* MTE_BOOL_LESSEQUAL    */
                ">",  /* MTE_BOOL_GREATER      */
                ">="  /* MTE_BOOL_GREATEREQUAL */  };

void
_mteTrigger_failure( /* int error, */ const char *msg )
{
    /*
     * XXX - Send an mteTriggerFailure trap
     *           (if configured to do so)
     */
    mteTriggerFailures++;
    snmp_log(LOG_ERR, "%s\n", msg );
    return;
}

void
mteTrigger_run( unsigned int reg, void *clientarg)
{
    struct mteTrigger *entry = (struct mteTrigger *)clientarg;
    netsnmp_variable_list *var, *vtmp;
    netsnmp_variable_list *vp1, *vp1_prev;
    netsnmp_variable_list *vp2, *vp2_prev;
    netsnmp_variable_list *dvar = NULL;
    netsnmp_variable_list *dv1  = NULL, *dv2 = NULL;
    netsnmp_variable_list sysUT_var;
    int  cmp = 0, n, n2;
    long value;
    const char *reason;

    if (!entry) {
        snmp_alarm_unregister( reg );
        return;
    }
    if (!(entry->flags & MTE_TRIGGER_FLAG_ENABLED ) ||
        !(entry->flags & MTE_TRIGGER_FLAG_ACTIVE  ) ||
        !(entry->flags & MTE_TRIGGER_FLAG_VALID  )) {
        return;
    }

    {
	extern netsnmp_agent_session *netsnmp_processing_set;
	if (netsnmp_processing_set) {
	    /*
	     * netsnmp_handle_request will not be responsive to our efforts to
	     *	Retrieve the requested MIB value(s)...
	     * so we will skip it.
	     * https://sourceforge.net/tracker/
	     *	index.php?func=detail&aid=1557406&group_id=12694&atid=112694
	     */
	    DEBUGMSGTL(("disman:event:trigger:monitor",
		"Skipping trigger (%s) while netsnmp_processing_set\n",
		entry->mteTName));
	    return;
	}
    }

    /*
     * Retrieve the requested MIB value(s)...
     */
    DEBUGMSGTL(( "disman:event:trigger:monitor", "Running trigger (%s)\n", entry->mteTName));
    var = (netsnmp_variable_list *)SNMP_MALLOC_TYPEDEF( netsnmp_variable_list );
    if (!var) {
        _mteTrigger_failure("failed to create mteTrigger query varbind");
        return;
    }
    snmp_set_var_objid( var, entry->mteTriggerValueID,
                             entry->mteTriggerValueID_len );
    if ( entry->flags & MTE_TRIGGER_FLAG_VWILD ) {
        n = netsnmp_query_walk( var, entry->session );
    } else {
        n = netsnmp_query_get(  var, entry->session );
    }
    if ( n != SNMP_ERR_NOERROR ) {
        DEBUGMSGTL(( "disman:event:trigger:monitor", "Trigger query (%s) failed: %d\n",
                           (( entry->flags & MTE_TRIGGER_FLAG_VWILD ) ? "walk" : "get"), n));
        _mteTrigger_failure( "failed to run mteTrigger query" );
        return;
    }

    /*
     * ... canonicalise the results (to simplify later comparisons)...
     */

    vp1 = var;                vp1_prev = NULL;
    vp2 = entry->old_results; vp2_prev = NULL;
    entry->count=0;
    while (vp1) {
           /*
            * Flatten various missing values/exceptions into a single form
            */ 
	switch (vp1->type) {
        case SNMP_NOSUCHINSTANCE:
        case SNMP_NOSUCHOBJECT:
        case ASN_PRIV_RETRY:   /* Internal only ? */
            vp1->type = ASN_NULL;
        }
           /*
            * Keep track of how many entries have been retrieved.
            */ 
           entry->count++;
        
           /*
            * Ensure previous and current result match
            *  (with corresponding entries in both lists)
            * and set the flags indicating which triggers are armed
            */ 
        if (vp2) {
            cmp = snmp_oid_compare(vp1->name, vp1->name_length,
                                   vp2->name, vp2->name_length);
            if ( cmp < 0 ) {
                /*
                 * If a new value has appeared, insert a matching
                 * dummy entry into the previous result list.
                 *
                 * XXX - check how this is best done.
                 */
                vtmp = SNMP_MALLOC_TYPEDEF( netsnmp_variable_list );
                if (!vtmp) {
                    _mteTrigger_failure(
                          "failed to create mteTrigger temp varbind");