[grpc] Add SSL session client cache support

1 files changed, 73 insertions, 0 deletions

diff --git a/src/core/tsi/ssl/session_cache/ssl_session.h b/src/core/tsi/ssl/session_cache/ssl_session.h
new file mode 100644
index 0000000000..115221ec06
--- /dev/null
+++ b/src/core/tsi/ssl/session_cache/ssl_session.h
@@ -0,0 +1,73 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#ifndef GRPC_CORE_TSI_SSL_SESSION_CACHE_SSL_SESSION_H
+#define GRPC_CORE_TSI_SSL_SESSION_CACHE_SSL_SESSION_H
+
+#include <grpc/support/port_platform.h>
+
+#include <grpc/slice.h>
+
+extern "C" {
+#include <openssl/ssl.h>
+}
+
+#include "src/core/lib/gprpp/ref_counted.h"
+
+// The main purpose of code here is to provide means to cache SSL sessions
+// in a way that they can be shared between connections.
+//
+// SSL_SESSION stands for single instance of session and is not generally safe
+// to share between SSL contexts with different lifetimes. It happens because
+// not all SSL implementations guarantee immutability of SSL_SESSION object.
+// See SSL_SESSION documentation in BoringSSL and OpenSSL for more details.
+
+namespace tsi {
+
+struct SslSessionDeleter {
+  void operator()(SSL_SESSION* session) { SSL_SESSION_free(session); }
+};
+
+typedef std::unique_ptr<SSL_SESSION, SslSessionDeleter> SslSessionPtr;
+
+/// SslCachedSession is an immutable thread-safe storage for single session
+/// representation. It provides means to share SSL session data (e.g. TLS
+/// ticket) between encrypted connections regardless of SSL context lifetime.
+class SslCachedSession {
+ public:
+  // Not copyable nor movable.
+  SslCachedSession(const SslCachedSession&) = delete;
+  SslCachedSession& operator=(const SslCachedSession&) = delete;
+
+  /// Create single cached instance of \a session.
+  static grpc_core::UniquePtr<SslCachedSession> Create(SslSessionPtr session);
+
+  virtual ~SslCachedSession() = default;
+
+  /// Returns a copy of previously cached session.
+  virtual SslSessionPtr CopySession() const GRPC_ABSTRACT;
+
+  GRPC_ABSTRACT_BASE_CLASS
+
+ protected:
+  SslCachedSession() = default;
+};
+
+}  // namespace tsi
+
+#endif /* GRPC_CORE_TSI_SSL_SESSION_CACHE_SSL_SESSION_H */