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| -rw-r--r-- | source3/libsmb/conncache.c | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/source3/libsmb/conncache.c b/source3/libsmb/conncache.c new file mode 100644 index 0000000000..ab0501b0be --- /dev/null +++ b/source3/libsmb/conncache.c @@ -0,0 +1,158 @@ +/* + 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_byname: 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_byname: 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; + } + +} + + |