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-rw-r--r--source3/libsmb/conncache.c158
1 files changed, 158 insertions, 0 deletions
diff --git a/source3/libsmb/conncache.c b/source3/libsmb/conncache.c
new file mode 100644
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+++ b/source3/libsmb/conncache.c
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+/*
+ Unix SMB/CIFS implementation.
+
+ Winbind daemon connection manager
+
+ Copyright (C) Tim Potter 2001
+ Copyright (C) Andrew Bartlett 2002
+ Copyright (C) Gerald (Jerry) Carter 2003
+
+ 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 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ 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.
+*/
+
+
+#include "includes.h"
+
+#define FAILED_CONNECTION_CACHE_TIMEOUT 30 /* Seconds between attempts */
+
+#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
+**********************************************************************/
+
+NTSTATUS check_negative_conn_cache( 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;
+
+ 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 ((time(NULL) - fcc->lookup_time) > FAILED_CONNECTION_CACHE_TIMEOUT)
+ {
+ /* Cache entry has expired, delete it */
+
+ DEBUG(10, ("check_negative_conn_cache: cache entry expired for %s, %s\n",
+ domain, server ));
+
+ DLIST_REMOVE(failed_connection_cache, fcc);
+ SAFE_FREE(fcc);
+
+ return NT_STATUS_OK;
+ }
+
+ /* The timeout hasn't expired yet so return false */
+
+ DEBUG(10, ("check_negative_conn_cache: returning negative entry for %s, %s\n",
+ domain, server ));
+
+ result = fcc->nt_status;
+ return result;
+ }
+
+ /* end of function means no cache entry */
+ return NT_STATUS_OK;
+}
+
+/**********************************************************************
+ 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)
+{
+ struct failed_connection_cache *fcc;
+
+ 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. */
+
+ 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 ));
+ return;
+ }
+ }
+
+ /* Create negative lookup cache entry for this domain and controller */
+
+ if ( !(fcc = (struct failed_connection_cache *)malloc(sizeof(struct failed_connection_cache))) )
+ {
+ DEBUG(0, ("malloc failed in add_failed_connection_entry!\n"));
+ return;
+ }
+
+ 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);
+}
+
+/****************************************************************************
+****************************************************************************/
+
+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;
+ }
+
+}
+
+