1 files changed, 227 insertions, 0 deletions
diff --git a/source3/libsmb/conncache.c b/source3/libsmb/conncache.c
new file mode 100644
index 0000000..7310b50
--- /dev/null
+++ b/source3/libsmb/conncache.c
@@ -0,0 +1,227 @@
+/*
+   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;
+}