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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 ));
/* 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;
}
}
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