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#include <net-snmp/net-snmp-config.h>
#if HAVE_STRING_H
#include <string.h>
#else
#include <strings.h>
#endif
#include <net-snmp/net-snmp-includes.h>
#include <net-snmp/agent/net-snmp-agent-includes.h>
#include <net-snmp/agent/stash_cache.h>
#if HAVE_DMALLOC_H
#include <dmalloc.h>
#endif
/** @defgroup stash_cache stash_cache
* Automatically caches data for certain handlers.
* This handler caches data in an optimized way which may aleviate
* the need for the lower level handlers to perform as much
* optimization. Specifically, somewhere in the lower level handlers
* must be a handler that supports the MODE_GET_STASH operation.
* Note that the table_iterator helper supports this.
* @ingroup handler
* @{
*/
netsnmp_stash_cache_info *
netsnmp_get_new_stash_cache(void)
{
netsnmp_stash_cache_info *cinfo;
cinfo = SNMP_MALLOC_TYPEDEF(netsnmp_stash_cache_info);
cinfo->cache_length = 30;
return cinfo;
}
/** returns a stash_cache handler that can be injected into a given
* handler chain.
*/
netsnmp_mib_handler *
netsnmp_get_stash_cache_handler(void)
{
netsnmp_mib_handler *handler;
netsnmp_stash_cache_info *cinfo;
cinfo = netsnmp_get_new_stash_cache();
if (!cinfo)
return NULL;
handler = netsnmp_create_handler("stash_cache", netsnmp_stash_cache_helper);
if (!handler) {
free(cinfo);
return NULL;
}
handler->myvoid = cinfo;
return handler;
}
/** extracts a pointer to the stash_cache info from the reqinfo structure. */
netsnmp_oid_stash_node **
netsnmp_extract_stash_cache(netsnmp_agent_request_info *reqinfo)
{
return netsnmp_agent_get_list_data(reqinfo, STASH_CACHE_NAME);
}
/** @internal Implements the stash_cache handler */
int
netsnmp_stash_cache_helper(netsnmp_mib_handler *handler,
netsnmp_handler_registration *reginfo,
netsnmp_agent_request_info *reqinfo,
netsnmp_request_info *requests)
{
netsnmp_stash_cache_info *cinfo;
netsnmp_oid_stash_node *cnode;
netsnmp_variable_list *cdata;
netsnmp_request_info *request;
int ret;
DEBUGMSGTL(("helper:stash_cache", "Got request\n"));
cinfo = (netsnmp_stash_cache_info *) handler->myvoid;
if (!cinfo) {
cinfo = netsnmp_get_new_stash_cache();
handler->myvoid = cinfo;
}
switch (reqinfo->mode) {
case MODE_GET:
if ((ret = netsnmp_stash_cache_update(handler, reginfo,
reqinfo, requests, cinfo)))
return ret;
for(request = requests; request; request = request->next) {
cdata =
netsnmp_oid_stash_get_data(cinfo->cache,
requests->requestvb->name,
requests->requestvb->name_length);
if (cdata && cdata->val.string && cdata->val_len) {
snmp_set_var_typed_value(request->requestvb, cdata->type,
cdata->val.string, cdata->val_len);
}
}
return SNMP_ERR_NOERROR;
break;
case MODE_GETNEXT:
if ((ret = netsnmp_stash_cache_update(handler, reginfo,
reqinfo, requests, cinfo)))
return ret;
for(request = requests; request; request = request->next) {
cnode =
netsnmp_oid_stash_getnext_node(cinfo->cache,
requests->requestvb->name,
requests->requestvb->name_length);
if (cnode && cnode->thedata) {
cdata = cnode->thedata;
if (cdata->val.string && cdata->name && cdata->name_length) {
snmp_set_var_typed_value(request->requestvb, cdata->type,
cdata->val.string, cdata->val_len);
snmp_set_var_objid(request->requestvb, cdata->name,
cdata->name_length);
}
}
}
return SNMP_ERR_NOERROR;
break;
default:
cinfo->cache_valid = 0;
return netsnmp_call_next_handler(handler, reginfo, reqinfo,
requests);
}
return SNMP_ERR_GENERR; /* should never get here */
}
/** updates a given cache depending on whether it needs to or not.
*/
int
netsnmp_stash_cache_update(netsnmp_mib_handler *handler,
netsnmp_handler_registration *reginfo,
netsnmp_agent_request_info *reqinfo,
netsnmp_request_info *requests,
netsnmp_stash_cache_info *cinfo)
{
int old_mode;
int ret;
if (!cinfo->cache_time ||
atime_ready(cinfo->cache_time, 1000*cinfo->cache_length)) {
DEBUGMSGTL(("stash_cache",
"(re)filling cache (done every %d seconds)\n",
cinfo->cache_length));
/* free the old */
netsnmp_oid_stash_free(&cinfo->cache,
(NetSNMPStashFreeNode *) snmp_free_var);
/* change modes to the GET_STASH mode */
old_mode = reqinfo->mode;
reqinfo->mode = MODE_GET_STASH;
netsnmp_agent_add_list_data(reqinfo,
netsnmp_create_data_list(STASH_CACHE_NAME,
&cinfo->cache,
NULL));
/* have the next handler fill stuff in and switch modes back */
ret = netsnmp_call_next_handler(handler, reginfo, reqinfo, requests);
reqinfo->mode = old_mode;
/* update the cache time */
if (cinfo->cache_time) {
atime_setMarker(cinfo->cache_time);
} else {
cinfo->cache_time = atime_newMarker();
}
return ret;
}
return SNMP_ERR_NOERROR;
}
/** initializes the stash_cache helper which then registers a stash_cache
* handler as a run-time injectable handler for configuration file
* use.
*/
void
netsnmp_init_stash_cache_helper(void)
{
netsnmp_register_handler_by_name("stash_cache",
netsnmp_get_stash_cache_handler());
}
/** @} */
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