table_tdata.c

开发snmp的开发包有两个开放的SNMP开发库

/** Creates a tdata handler and returns it */
netsnmp_mib_handler *
netsnmp_get_tdata_handler(netsnmp_tdata *table)
{
    netsnmp_mib_handler *ret = NULL;

    if (!table) {
        snmp_log(LOG_INFO,
                 "netsnmp_get_tdata_handler(NULL) called\n");
        return NULL;
    }

    ret = netsnmp_create_handler(TABLE_TDATA_NAME,
                               _netsnmp_tdata_helper_handler);
    if (ret) {
        ret->flags |= MIB_HANDLER_AUTO_NEXT;
        ret->myvoid = (void *) table;
    }
    return ret;
}

/*
 * The helper handler that takes care of passing a specific row of
 * data down to the lower handler(s).  The table_container helper
 * has already taken care of identifying the appropriate row of the
 * table (and converting GETNEXT requests into an equivalent GET request)
 * So all we need to do here is make sure that the row is accessible
 * using tdata-style retrieval techniques as well.
 */
int
_netsnmp_tdata_helper_handler(netsnmp_mib_handler *handler,
                                  netsnmp_handler_registration *reginfo,
                                  netsnmp_agent_request_info *reqinfo,
                                  netsnmp_request_info *requests)
{
    netsnmp_tdata *table = (netsnmp_tdata *) handler->myvoid;
    netsnmp_request_info       *request;
    netsnmp_table_request_info *table_info;
    netsnmp_tdata_row          *row;

    switch ( reqinfo->mode ) {
    case MODE_GET:
    case MODE_SET_RESERVE1:

        for (request = requests; request; request = request->next) {
            if (request->processed)
                continue;
    
            table_info = netsnmp_extract_table_info(request);
            if (!table_info)
                continue;           /* ack */
            row = netsnmp_container_table_row_extract( request );

            netsnmp_request_add_list_data(request,
                                      netsnmp_create_data_list(
                                          TABLE_TDATA_TABLE, table, NULL));
            netsnmp_request_add_list_data(request,
                                      netsnmp_create_data_list(
                                          TABLE_TDATA_ROW,   row,   NULL));
        }
    }

    /* next handler called automatically - 'AUTO_NEXT' */
    return SNMP_ERR_NOERROR;
}


/** registers a tdata-based MIB table */
int
netsnmp_tdata_register(netsnmp_handler_registration    *reginfo,
                       netsnmp_tdata                   *table,
                       netsnmp_table_registration_info *table_info)
{
    netsnmp_inject_handler(reginfo, netsnmp_get_tdata_handler(table));
    return netsnmp_container_table_register(reginfo, table_info,
                  table->container, TABLE_CONTAINER_KEY_NETSNMP_INDEX);
}

/** extracts the tdata table from the request structure */
netsnmp_tdata *
netsnmp_tdata_extract_table(netsnmp_request_info *request)
{
    return (netsnmp_tdata *) netsnmp_request_get_list_data(request,
                                                           TABLE_TDATA_TABLE);
}

/** extracts the tdata container from the request structure */
netsnmp_container *
netsnmp_tdata_extract_container(netsnmp_request_info *request)
{
    netsnmp_tdata *tdata = netsnmp_request_get_list_data(request,
                                                         TABLE_TDATA_TABLE);
    return ( tdata ? tdata->container : NULL );
}

/** extracts the tdata row being accessed from the request structure */
netsnmp_tdata_row *
netsnmp_tdata_extract_row(netsnmp_request_info *request)
{
    return (netsnmp_tdata_row *) netsnmp_container_table_row_extract(request);
}

/** extracts the (table-specific) entry being accessed from the
 *  request structure */
void           *
netsnmp_tdata_extract_entry(netsnmp_request_info *request)
{
    netsnmp_tdata_row *row =
        (netsnmp_tdata_row *) netsnmp_tdata_extract_row(request);
    if (row)
        return row->data;
    else
        return NULL;
}

/** inserts a newly created tdata row into a request */
NETSNMP_INLINE void
netsnmp_insert_tdata_row(netsnmp_request_info *request,
                         netsnmp_tdata_row *row)
{
    netsnmp_container_table_row_insert(request, (netsnmp_index *)row);
}


/* ==================================
 *
 * Generic API: Row operations
 *
 * ================================== */

/** returns the (table-specific) entry data for a given row */
void *
netsnmp_tdata_row_entry( netsnmp_tdata_row *row )
{
    if (row)
        return row->data;
    else
        return NULL;
}

/** returns the first row in the table */
netsnmp_tdata_row *
netsnmp_tdata_row_first(netsnmp_tdata *table)
{
    return (netsnmp_tdata_row *)CONTAINER_FIRST( table->container );
}

/** finds a row in the 'tdata' table given another row */
netsnmp_tdata_row *
netsnmp_tdata_row_get(  netsnmp_tdata     *table,
                        netsnmp_tdata_row *row)
{
    return CONTAINER_FIND( table->container, row );
}

/** returns the next row in the table */
netsnmp_tdata_row *
netsnmp_tdata_row_next( netsnmp_tdata      *table,
                        netsnmp_tdata_row  *row)
{
    return (netsnmp_tdata_row *)CONTAINER_NEXT( table->container, row  );
}

/** finds a row in the 'tdata' table given the index values */
netsnmp_tdata_row *
netsnmp_tdata_row_get_byidx(netsnmp_tdata         *table,
                            netsnmp_variable_list *indexes)
{
    oid             searchfor[      MAX_OID_LEN];
    size_t          searchfor_len = MAX_OID_LEN;

    build_oid_noalloc(searchfor, MAX_OID_LEN, &searchfor_len, NULL, 0,
                      indexes);
    return netsnmp_tdata_row_get_byoid(table, searchfor, searchfor_len);
}

/** finds a row in the 'tdata' table given the index OID */
netsnmp_tdata_row *
netsnmp_tdata_row_get_byoid(netsnmp_tdata *table,
                            oid * searchfor, size_t searchfor_len)
{
    netsnmp_index index;
    if (!table)
        return NULL;

    index.oids = searchfor;
    index.len  = searchfor_len;
    return CONTAINER_FIND( table->container, &index );
}

/** finds the lexically next row in the 'tdata' table
    given the index values */
netsnmp_tdata_row *
netsnmp_tdata_row_next_byidx(netsnmp_tdata         *table,
                             netsnmp_variable_list *indexes)
{
    oid             searchfor[      MAX_OID_LEN];
    size_t          searchfor_len = MAX_OID_LEN;

    build_oid_noalloc(searchfor, MAX_OID_LEN, &searchfor_len, NULL, 0,
                      indexes);
    return netsnmp_tdata_row_next_byoid(table, searchfor, searchfor_len);
}

/** finds the lexically next row in the 'tdata' table
    given the index OID */
netsnmp_tdata_row *
netsnmp_tdata_row_next_byoid(netsnmp_tdata *table,
                             oid * searchfor, size_t searchfor_len)
{
    netsnmp_index index;
    if (!table)
        return NULL;

    index.oids = searchfor;
    index.len  = searchfor_len;
    return CONTAINER_NEXT( table->container, &index );
}

int
netsnmp_tdata_row_count(netsnmp_tdata *table)
{
    if (!table)
        return 0;
    return CONTAINER_SIZE( table->container );
}

/* ==================================
 *
 * Generic API: Index operations on a 'tdata' table
 *
 * ================================== */


/** compare a row with the given index values */
int
netsnmp_tdata_compare_idx(netsnmp_tdata_row     *row,
                          netsnmp_variable_list *indexes)
{
    oid             searchfor[      MAX_OID_LEN];
    size_t          searchfor_len = MAX_OID_LEN;

    build_oid_noalloc(searchfor, MAX_OID_LEN, &searchfor_len, NULL, 0,
                      indexes);
    return netsnmp_tdata_compare_oid(row, searchfor, searchfor_len);
}

/** compare a row with the given index OID */
int
netsnmp_tdata_compare_oid(netsnmp_tdata_row     *row,
                          oid * compareto, size_t compareto_len)
{
    netsnmp_index *index = (netsnmp_index *)row;
    return snmp_oid_compare( index->oids, index->len,
                             compareto,   compareto_len);
}

int
netsnmp_tdata_compare_subtree_idx(netsnmp_tdata_row     *row,
                                  netsnmp_variable_list *indexes)
{
    oid             searchfor[      MAX_OID_LEN];
    size_t          searchfor_len = MAX_OID_LEN;

    build_oid_noalloc(searchfor, MAX_OID_LEN, &searchfor_len, NULL, 0,
                      indexes);
    return netsnmp_tdata_compare_subtree_oid(row, searchfor, searchfor_len);
}

int
netsnmp_tdata_compare_subtree_oid(netsnmp_tdata_row     *row,
                                  oid * compareto, size_t compareto_len)
{
    netsnmp_index *index = (netsnmp_index *)row;
    return snmp_oidtree_compare( index->oids, index->len,
                                 compareto,   compareto_len);
}

/** @} 
 */