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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-05 17:47:29 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-05 17:47:29 +0000
commit4f5791ebd03eaec1c7da0865a383175b05102712 (patch)
tree8ce7b00f7a76baa386372422adebbe64510812d4 /source3/libsmb/conncache.c
parentInitial commit. (diff)
downloadsamba-4f5791ebd03eaec1c7da0865a383175b05102712.tar.xz
samba-4f5791ebd03eaec1c7da0865a383175b05102712.zip
Adding upstream version 2:4.17.12+dfsg.upstream/2%4.17.12+dfsgupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'source3/libsmb/conncache.c')
-rw-r--r--source3/libsmb/conncache.c227
1 files changed, 227 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
+ Copyright (C) Marc VanHeyningen 2008
+ Copyright (C) Volker Lendecke 2009
+
+ 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 3 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, see <http://www.gnu.org/licenses/>.
+*/
+
+
+#include "includes.h"
+#include "lib/gencache.h"
+
+/**
+ * @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
+ */
+
+
+/**
+ * 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)
+{
+ char *keystr = NULL;
+
+ if (domain == NULL) {
+ return NULL;
+ }
+ if (server == NULL)
+ server = "";
+
+ keystr = talloc_asprintf(talloc_tos(), "NEG_CONN_CACHE/%s,%s",
+ domain, server);
+ if (keystr == NULL) {
+ DEBUG(0, ("negative_conn_cache_keystr: malloc error\n"));
+ }
+
+ return keystr;
+}
+
+/**
+ * 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;
+
+ valuestr = talloc_asprintf(talloc_tos(), "%x", NT_STATUS_V(status));
+ if (valuestr == NULL) {
+ DEBUG(0, ("negative_conn_cache_valuestr: malloc error\n"));
+ }
+
+ return valuestr;
+}
+
+/**
+ * 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)
+{
+ unsigned int v = NT_STATUS_V(NT_STATUS_INTERNAL_ERROR);
+
+ if (value == NULL) {
+ return NT_STATUS_INTERNAL_ERROR;
+ }
+ if (sscanf(value, "%x", &v) != 1) {
+ DEBUG(0, ("negative_conn_cache_valuedecode: unable to parse "
+ "value field '%s'\n", value));
+ }
+ return NT_STATUS(v);
+}
+
+/**
+ * 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)
+{
+ 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, talloc_tos(), &value, 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));
+ TALLOC_FREE(key);
+ TALLOC_FREE(value);
+ return result;
+}
+
+/**
+ * Add an entry to the failed connection 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;
+
+ if (NT_STATUS_IS_OK(result)) {
+ /* Nothing failed here */
+ return;
+ }
+
+ key = negative_conn_cache_keystr(domain, server);
+ if (key == NULL) {
+ DEBUG(0, ("add_failed_connection_entry: key creation error\n"));
+ goto done;
+ }
+
+ value = negative_conn_cache_valuestr(result);
+ if (value == NULL) {
+ DEBUG(0, ("add_failed_connection_entry: value creation error\n"));
+ goto done;
+ }
+
+ if (gencache_set(key, value,
+ time(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));
+
+ done:
+ TALLOC_FREE(key);
+ TALLOC_FREE(value);
+ return;
+}
+
+/**
+ * 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)
+{
+ char *key_pattern = NULL;
+
+ 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, NULL, key_pattern);
+ DEBUG(8, ("flush_negative_conn_cache_for_domain: flushed domain %s\n",
+ domain));
+
+ done:
+ TALLOC_FREE(key_pattern);
+ return;
+}