cache_handler.h

00001 /* Portions of this file are subject to the following copyright(s).  See
00002  * the Net-SNMP's COPYING file for more details and other copyrights
00003  * that may apply:
00004  */
00005 /*
00006  * Portions of this file are copyrighted by:
00007  * Copyright (C) 2007 Apple, Inc. All rights reserved.
00008  * Use is subject to license terms specified in the COPYING file
00009  * distributed with the Net-SNMP package.
00010  */
00011 #ifndef NETSNMP_CACHE_HANDLER_H
00012 #define NETSNMP_CACHE_HANDLER_H
00013 
00014 /*
00015  * This caching helper provides a generalised (SNMP-manageable) caching
00016  * mechanism.  Individual SNMP table and scalar/scalar group MIB
00017  * implementations can use data caching in a consistent manner, without
00018  * needing to handle the generic caching details themselves.
00019  */
00020 
00021 #include <net-snmp/library/tools.h>
00022 
00023 #ifdef __cplusplus
00024 extern          "C" {
00025 #endif
00026 
00027 #define CACHE_NAME "cache_info"
00028 
00029     typedef struct netsnmp_cache_s netsnmp_cache;
00030 
00031     typedef int  (NetsnmpCacheLoad)(netsnmp_cache *, void*);
00032     typedef void (NetsnmpCacheFree)(netsnmp_cache *, void*);
00033 
00034     struct netsnmp_cache_s {
00035         /*
00036          * For operation of the data caches
00037          */
00038         int      flags;
00039         int      enabled;
00040         int      valid;
00041         char     expired;
00042         int      timeout;       /* Length of time the cache is valid (in s) */
00043         marker_t timestamp;     /* When the cache was last loaded */
00044         u_long   timer_id;      /* periodic timer id */
00045 
00046         NetsnmpCacheLoad *load_cache;
00047         NetsnmpCacheFree *free_cache;
00048 
00049        /*
00050         * void pointer for the user that created the cache.
00051         * You never know when it might not come in useful ....
00052         */
00053         void             *magic;
00054 
00055        /*
00056         * hint from the cache helper. contains the standard
00057         * handler arguments.
00058         */
00059        netsnmp_handler_args          *cache_hint;
00060 
00061         /*
00062          * For SNMP-management of the data caches
00063          */
00064         netsnmp_cache *next, *prev;
00065         oid *rootoid;
00066         int  rootoid_len;
00067 
00068     };
00069 
00070 
00071     void netsnmp_cache_reqinfo_insert(netsnmp_cache* cache,
00072                                       netsnmp_agent_request_info * reqinfo,
00073                                       const char *name);
00074     netsnmp_cache  *
00075        netsnmp_cache_reqinfo_extract(netsnmp_agent_request_info * reqinfo,
00076                                      const char *name);
00077     netsnmp_cache* netsnmp_extract_cache_info(netsnmp_agent_request_info *);
00078 
00079     int            netsnmp_cache_check_and_reload(netsnmp_cache * cache);
00080     int            netsnmp_cache_check_expired(netsnmp_cache *cache);
00081     int            netsnmp_cache_is_valid(    netsnmp_agent_request_info *,
00082                                               const char *name);
00084     int            netsnmp_is_cache_valid(    netsnmp_agent_request_info *);
00085     netsnmp_mib_handler *netsnmp_get_cache_handler(int, NetsnmpCacheLoad *,
00086                                                         NetsnmpCacheFree *,
00087                                                         const oid*, int);
00088     int   netsnmp_register_cache_handler(netsnmp_handler_registration *reginfo,
00089                                          int, NetsnmpCacheLoad *,
00090                                               NetsnmpCacheFree *);
00091 
00092     Netsnmp_Node_Handler netsnmp_cache_helper_handler;
00093 
00094     netsnmp_cache *
00095     netsnmp_cache_create(int timeout, NetsnmpCacheLoad * load_hook,
00096                          NetsnmpCacheFree * free_hook,
00097                          const oid * rootoid, int rootoid_len);
00098     int netsnmp_cache_free(netsnmp_cache *cache);
00099 
00100     netsnmp_mib_handler *
00101     netsnmp_cache_handler_get(netsnmp_cache* cache);
00102 
00103     netsnmp_cache * netsnmp_cache_find_by_oid(const oid * rootoid,
00104                                               int rootoid_len);
00105 
00106     unsigned int netsnmp_cache_timer_start(netsnmp_cache *cache);
00107     void netsnmp_cache_timer_stop(netsnmp_cache *cache);
00108 
00109 /*
00110  * Flags affecting cache handler operation
00111  */
00112 #define NETSNMP_CACHE_DONT_INVALIDATE_ON_SET                0x0001
00113 #define NETSNMP_CACHE_DONT_FREE_BEFORE_LOAD                 0x0002
00114 #define NETSNMP_CACHE_DONT_FREE_EXPIRED                     0x0004
00115 #define NETSNMP_CACHE_DONT_AUTO_RELEASE                     0x0008
00116 #define NETSNMP_CACHE_PRELOAD                               0x0010
00117 #define NETSNMP_CACHE_AUTO_RELOAD                           0x0020
00118 
00119 #define NETSNMP_CACHE_HINT_HANDLER_ARGS                     0x1000
00120 
00121 
00122 #ifdef __cplusplus
00123 }
00124 #endif
00125 #endif /* NETSNMP_CACHE_HANDLER_H */