[grpc] Add SSL session client cache support

1 files changed, 58 insertions, 0 deletions

diff --git a/src/core/tsi/ssl/session_cache/ssl_session_boringssl.cc b/src/core/tsi/ssl/session_cache/ssl_session_boringssl.cc
new file mode 100644
index 0000000000..0da5a96164
--- /dev/null
+++ b/src/core/tsi/ssl/session_cache/ssl_session_boringssl.cc
@@ -0,0 +1,58 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#include "src/core/tsi/ssl/session_cache/ssl_session.h"
+
+#ifdef OPENSSL_IS_BORINGSSL
+
+// BoringSSL allows SSL_SESSION to outlive SSL and SSL_CTX objects which are
+// re-created by gRPC on every certificate rotation or subchannel creation.
+// BoringSSL guarantees that SSL_SESSION is immutable so it's safe to share
+// the same original session object between different threads and connections.
+
+namespace tsi {
+namespace {
+
+class BoringSslCachedSession : public SslCachedSession {
+ public:
+  BoringSslCachedSession(SslSessionPtr session)
+      : session_(std::move(session)) {}
+
+  SslSessionPtr CopySession() const override {
+    // SslSessionPtr will dereference on destruction.
+    SSL_SESSION_up_ref(session_.get());
+    return SslSessionPtr(session_.get());
+  }
+
+ private:
+  SslSessionPtr session_;
+};
+
+}  // namespace
+
+grpc_core::UniquePtr<SslCachedSession> SslCachedSession::Create(
+    SslSessionPtr session) {
+  return grpc_core::UniquePtr<SslCachedSession>(
+      grpc_core::New<BoringSslCachedSession>(std::move(session)));
+}
+
+}  // namespace tsi
+
+#endif /* OPENSSL_IS_BORINGSSL */