diff options
| -rw-r--r-- | source3/libsmb/conncache.c | 318 |
1 files changed, 189 insertions, 129 deletions
diff --git a/source3/libsmb/conncache.c b/source3/libsmb/conncache.c index c4a87623d7..2df45c2b0f 100644 --- a/source3/libsmb/conncache.c +++ b/source3/libsmb/conncache.c @@ -6,6 +6,7 @@ Copyright (C) Tim Potter 2001 Copyright (C) Andrew Bartlett 2002 Copyright (C) Gerald (Jerry) Carter 2003 + Copyright (C) Marc VanHeyningen 2008 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 @@ -24,168 +25,227 @@ #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 + */ + + +/** + * prefix used for all entries put into the general cache + */ +static const char NEGATIVE_CONN_CACHE_PREFIX[] = "NEG_CONN_CACHE"; + +/** + * 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; + const char NEGATIVE_CONN_CACHE_KEY_FMT[] = "%s/%s,%s"; + char *keystr = NULL; - for (fcc = failed_connection_cache; fcc; fcc = fcc->next) { + SMB_ASSERT(domain != NULL); + if (server == NULL) + server = ""; - 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 (asprintf(&keystr, NEGATIVE_CONN_CACHE_KEY_FMT, + NEGATIVE_CONN_CACHE_PREFIX, domain, server) == -1) + 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; - } - } + if (asprintf(&valuestr, "%x", NT_STATUS_V(status)) == -1) + 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) +{ + NTSTATUS result = NT_STATUS_OK; - result = fcc->nt_status; - return result; - } + SMB_ASSERT(value != NULL); + if (sscanf(value, "%x", &(NT_STATUS_V(result))) != 1) + DEBUG(0, ("negative_conn_cache_valuestr: unable to parse " + "value field '%s'\n", value)); + return result; +} - /* 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, (time_t *) 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)); + SAFE_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: + SAFE_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. */ - - 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; - } - } +/** + * Add an entry to the failed conneciton 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; - /* Create negative lookup cache entry for this domain and controller */ + SMB_ASSERT(!NT_STATUS_IS_OK(result)); - if ( !(fcc = SMB_MALLOC_P(struct failed_connection_cache)) ) { - DEBUG(0, ("malloc failed in add_failed_connection_entry!\n")); - return; + key = negative_conn_cache_keystr(domain, server); + if (key == NULL) { + DEBUG(0, ("add_failed_connection_entry: key creation error\n")); + goto done; } - ZERO_STRUCTP(fcc); - - fstrcpy( fcc->domain_name, domain ); - fstrcpy( fcc->controller, server ); - fcc->lookup_time = time(NULL); - fcc->nt_status = result; + value = negative_conn_cache_valuestr(result); + if (value == NULL) { + DEBUG(0, ("add_failed_connection_entry: value creation error\n")); + goto done; + } - DEBUG(10,("add_failed_connection_entry: added domain %s (%s) to failed conn cache\n", - domain, server )); + if (gencache_set(key, value, + time((time_t *) 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)); - DLIST_ADD(failed_connection_cache, fcc); + done: + SAFE_FREE(key); + SAFE_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; - - 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); - } - - fcc = 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; } + + gencache_iterate(delete_matches, (void *) NULL, key_pattern); + DEBUG(8, ("flush_negative_conn_cache_for_domain: flushed domain %s\n", + domain)); + + done: + SAFE_FREE(key_pattern); + return; } |