Copyright (C) Tim Potter 2001
Copyright (C) Andrew Bartlett 2002
Copyright (C) Gerald (Jerry) Carter 2003
-
+ Copyright (C) Marc VanHeyningen 2008
+ Copyright (C) Volker Lendecke 2009
+
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
-#define CONNCACHE_ADDR 1
-#define CONNCACHE_NAME 2
-
-/* cache entry contains either a server name **or** and IP address as
- the key. This means that a server could have two entries (one for each key) */
-
-struct failed_connection_cache {
- fstring domain_name;
- fstring controller;
- time_t lookup_time;
- NTSTATUS nt_status;
- struct failed_connection_cache *prev, *next;
-};
-
-static struct failed_connection_cache *failed_connection_cache;
-
-/**********************************************************************
- Check for a previously failed connection.
- failed_cache_timeout is an a absolute number of seconds after which
- we should time this out. If failed_cache_timeout == 0 then time out
- immediately. If failed_cache_timeout == -1 then never time out.
-**********************************************************************/
-
-NTSTATUS check_negative_conn_cache_timeout( const char *domain, const char *server, unsigned int failed_cache_timeout )
+/**
+ * @file
+ * Negative connection cache implemented in terms of gencache API
+ *
+ * The negative connection cache stores names of servers which have
+ * been unresponsive so that we don't waste time repeatedly trying
+ * to contact them. It used to use an in-memory linked list, but
+ * this limited its utility to a single process
+ */
+
+
+/**
+ * Marshalls the domain and server name into the key for the gencache
+ * record
+ *
+ * @param[in] domain required
+ * @param[in] server may be a FQDN or an IP address
+ * @return the resulting string, which the caller is responsible for
+ * SAFE_FREE()ing
+ * @retval NULL returned on error
+ */
+static char *negative_conn_cache_keystr(const char *domain, const char *server)
{
- struct failed_connection_cache *fcc;
- NTSTATUS result = NT_STATUS_UNSUCCESSFUL;
-
- /* can't check if we don't have strings */
-
- if ( !domain || !server )
- return NT_STATUS_OK;
+ char *keystr = NULL;
- for (fcc = failed_connection_cache; fcc; fcc = fcc->next) {
-
- if (!(strequal(domain, fcc->domain_name) && strequal(server, fcc->controller))) {
- continue; /* no match; check the next entry */
- }
-
- /* we have a match so see if it is still current */
- if (failed_cache_timeout != (unsigned int)-1) {
- if (failed_cache_timeout == 0 ||
- (time(NULL) - fcc->lookup_time) > (time_t)failed_cache_timeout) {
- /* Cache entry has expired, delete it */
+ if (domain == NULL) {
+ return NULL;
+ }
+ if (server == NULL)
+ server = "";
+
+ keystr = talloc_asprintf(talloc_tos(), "NEG_CONN_CACHE/%s,%s",
+ domain, server);
+ if (keystr == NULL) {
+ DEBUG(0, ("negative_conn_cache_keystr: malloc error\n"));
+ }
- DEBUG(10, ("check_negative_conn_cache: cache entry expired for %s, %s\n",
- domain, server ));
+ return keystr;
+}
- DLIST_REMOVE(failed_connection_cache, fcc);
- SAFE_FREE(fcc);
+/**
+ * Marshalls the NT status into a printable value field for the gencache
+ * record
+ *
+ * @param[in] status
+ * @return the resulting string, which the caller is responsible for
+ * SAFE_FREE()ing
+ * @retval NULL returned on error
+ */
+static char *negative_conn_cache_valuestr(NTSTATUS status)
+{
+ char *valuestr = NULL;
- return NT_STATUS_OK;
- }
- }
+ valuestr = talloc_asprintf(talloc_tos(), "%x", NT_STATUS_V(status));
+ if (valuestr == NULL) {
+ DEBUG(0, ("negative_conn_cache_valuestr: malloc error\n"));
+ }
- /* The timeout hasn't expired yet so return false */
+ return valuestr;
+}
- DEBUG(10, ("check_negative_conn_cache: returning negative entry for %s, %s\n",
- domain, server ));
+/**
+ * Un-marshalls the NT status from a printable field for the gencache
+ * record
+ *
+ * @param[in] value The value field from the record
+ * @return the decoded NT status
+ * @retval NT_STATUS_OK returned on error
+ */
+static NTSTATUS negative_conn_cache_valuedecode(const char *value)
+{
+ unsigned int v = NT_STATUS_V(NT_STATUS_INTERNAL_ERROR);;
- result = fcc->nt_status;
- return result;
+ if (value != NULL) {
+ return NT_STATUS_INTERNAL_ERROR;
}
+ if (sscanf(value, "%x", &v) != 1) {
+ DEBUG(0, ("negative_conn_cache_valuedecode: unable to parse "
+ "value field '%s'\n", value));
+ }
+ return NT_STATUS(v);
+}
- /* end of function means no cache entry */
- return NT_STATUS_OK;
+/**
+ * Function passed to gencache_iterate to remove any matching items
+ * from the list
+ *
+ * @param[in] key Key to the record found and to be deleted
+ * @param[in] value Value to the record (ignored)
+ * @param[in] timeout Timeout remaining for the record (ignored)
+ * @param[in] dptr Handle for passing additional data (ignored)
+ */
+static void delete_matches(const char *key, const char *value,
+ time_t timeout, void *dptr)
+{
+ gencache_del(key);
}
+
+/**
+ * Checks for a given domain/server record in the negative cache
+ *
+ * @param[in] domain
+ * @param[in] server may be either a FQDN or an IP address
+ * @return The cached failure status
+ * @retval NT_STATUS_OK returned if no record is found or an error occurs
+ */
NTSTATUS check_negative_conn_cache( const char *domain, const char *server)
{
- return check_negative_conn_cache_timeout(domain, server, FAILED_CONNECTION_CACHE_TIMEOUT);
+ NTSTATUS result = NT_STATUS_OK;
+ char *key = NULL;
+ char *value = NULL;
+
+ key = negative_conn_cache_keystr(domain, server);
+ if (key == NULL)
+ goto done;
+
+ if (gencache_get(key, &value, NULL))
+ result = negative_conn_cache_valuedecode(value);
+ done:
+ DEBUG(9,("check_negative_conn_cache returning result %d for domain %s "
+ "server %s\n", NT_STATUS_V(result), domain, server));
+ TALLOC_FREE(key);
+ SAFE_FREE(value);
+ return result;
}
-/**********************************************************************
- Add an entry to the failed conneciton cache (aither a name of dotted
- decimal IP
-**********************************************************************/
-
-void add_failed_connection_entry(const char *domain, const char *server, NTSTATUS result)
+/**
+ * Delete any negative cache entry for the given domain/server
+ *
+ * @param[in] domain
+ * @param[in] server may be either a FQDN or an IP address
+ */
+void delete_negative_conn_cache(const char *domain, const char *server)
{
- struct failed_connection_cache *fcc;
+ char *key = NULL;
+
+ key = negative_conn_cache_keystr(domain, server);
+ if (key == NULL)
+ goto done;
+
+ gencache_del(key);
+ DEBUG(9,("delete_negative_conn_cache removing domain %s server %s\n",
+ domain, server));
+ done:
+ TALLOC_FREE(key);
+ return;
+}
- SMB_ASSERT(!NT_STATUS_IS_OK(result));
- /* Check we already aren't in the cache. We always have to have
- a domain, but maybe not a specific DC name. */
+/**
+ * Add an entry to the failed connection cache
+ *
+ * @param[in] domain
+ * @param[in] server may be a FQDN or an IP addr in printable form
+ * @param[in] result error to cache; must not be NT_STATUS_OK
+ */
+void add_failed_connection_entry(const char *domain, const char *server,
+ NTSTATUS result)
+{
+ char *key = NULL;
+ char *value = NULL;
- for (fcc = failed_connection_cache; fcc; fcc = fcc->next) {
- if ( strequal(fcc->domain_name, domain) && strequal(fcc->controller, server) ) {
- DEBUG(10, ("add_failed_connection_entry: domain %s (%s) already tried and failed\n",
- domain, server ));
- /* Update the failed time. */
- fcc->lookup_time = time(NULL);
- return;
- }
+ if (NT_STATUS_IS_OK(result)) {
+ /* Nothing failed here */
+ return;
}
- /* Create negative lookup cache entry for this domain and controller */
+ key = negative_conn_cache_keystr(domain, server);
+ if (key == NULL) {
+ DEBUG(0, ("add_failed_connection_entry: key creation error\n"));
+ goto done;
+ }
- if ( !(fcc = SMB_MALLOC_P(struct failed_connection_cache)) ) {
- DEBUG(0, ("malloc failed in add_failed_connection_entry!\n"));
- return;
+ value = negative_conn_cache_valuestr(result);
+ if (value == NULL) {
+ DEBUG(0, ("add_failed_connection_entry: value creation error\n"));
+ goto done;
}
+
+ if (gencache_set(key, value,
+ time(NULL) + FAILED_CONNECTION_CACHE_TIMEOUT))
+ DEBUG(9,("add_failed_connection_entry: added domain %s (%s) "
+ "to failed conn cache\n", domain, server ));
+ else
+ DEBUG(1,("add_failed_connection_entry: failed to add "
+ "domain %s (%s) to failed conn cache\n",
+ domain, server));
- ZERO_STRUCTP(fcc);
-
- fstrcpy( fcc->domain_name, domain );
- fstrcpy( fcc->controller, server );
- fcc->lookup_time = time(NULL);
- fcc->nt_status = result;
-
- DEBUG(10,("add_failed_connection_entry: added domain %s (%s) to failed conn cache\n",
- domain, server ));
-
- DLIST_ADD(failed_connection_cache, fcc);
+ done:
+ TALLOC_FREE(key);
+ TALLOC_FREE(value);
+ return;
}
-/****************************************************************************
-****************************************************************************/
-
+/**
+ * Deletes all records from the negative connection cache in all domains
+ */
void flush_negative_conn_cache( void )
{
- struct failed_connection_cache *fcc;
-
- fcc = failed_connection_cache;
-
- while (fcc) {
- struct failed_connection_cache *fcc_next;
-
- fcc_next = fcc->next;
- DLIST_REMOVE(failed_connection_cache, fcc);
- free(fcc);
-
- fcc = fcc_next;
- }
-
+ flush_negative_conn_cache_for_domain("*");
}
-/****************************************************************************
- Remove all negative entries for a domain. Used when going to online state in
- winbindd.
-****************************************************************************/
-
+
+/**
+ * Deletes all records for a specified domain from the negative connection
+ * cache
+ *
+ * @param[in] domain String to match against domain portion of keys, or "*"
+ * to match all domains
+ */
void flush_negative_conn_cache_for_domain(const char *domain)
{
- struct failed_connection_cache *fcc;
-
- fcc = failed_connection_cache;
-
- while (fcc) {
- struct failed_connection_cache *fcc_next;
+ char *key_pattern = NULL;
- fcc_next = fcc->next;
+ key_pattern = negative_conn_cache_keystr(domain,"*");
+ if (key_pattern == NULL) {
+ DEBUG(0, ("flush_negative_conn_cache_for_domain: "
+ "key creation error\n"));
+ goto done;
+ }
- if (strequal(fcc->domain_name, domain)) {
- DEBUG(10,("flush_negative_conn_cache_for_domain: removed server %s "
- " from failed cache for domain %s\n",
- fcc->controller, domain));
- DLIST_REMOVE(failed_connection_cache, fcc);
- free(fcc);
- }
+ gencache_iterate(delete_matches, NULL, key_pattern);
+ DEBUG(8, ("flush_negative_conn_cache_for_domain: flushed domain %s\n",
+ domain));
- fcc = fcc_next;
- }
+ done:
+ TALLOC_FREE(key_pattern);
+ return;
}
git.samba.org / ira / wip.git / blobdiff