Initial import

[samba] / source / libsmb / conncache.c

diff --git a/source/libsmb/conncache.c b/source/libsmb/conncache.c
new file mode 100644 (file)
index 0000000..2af4d57
--- /dev/null
+++ b/source/libsmb/conncache.c
@@ -0,0 +1,156 @@
+/* 
+   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 ));
+                       /* Update the failed time. */
+                       fcc->lookup_time = time(NULL);
+                       return;
+               }
+       }
+
+       /* Create negative lookup cache entry for this domain and controller */
+
+       if ( !(fcc = SMB_MALLOC_P(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;
+       }
+
+}