nghttpx: Add more TLS related attributes to mruby Env object

The added attributes are:

* tls_cipher
* tls_protocol
* tls_session_id
* tls_session_reused
* alpn

doc/nghttpx.h2r

@@ -376,6 +376,26 @@ respectively.
 
         Return the subject name of a client certificate.
 
+    .. rb:attr_reader:: tls_cipher
+
+        Return a TLS cipher negotiated in this connection.
+
+    .. rb:attr_reader:: tls_protocol
+
+        Return a TLS protocol version negotiated in this connection.
+
+    .. rb:attr_reader:: tls_session_id
+
+        Return a session ID for this connection in hex string.
+
+    .. rb:attr_reader:: tls_session_reused
+
+        Return true if, and only if a SSL/TLS session is reused.
+
+    .. rb:attr_reader:: alpn
+
+        Return ALPN identifier negotiated in this connection.
+
 .. rb:class:: Request
 
     Object to represent request from client.  The modification to

src/shrpx_client_handler.cc

@@ -1481,6 +1481,8 @@ void ClientHandler::set_tls_sni(const StringRef &sni) {
 
 StringRef ClientHandler::get_tls_sni() const { return sni_; }
 
+StringRef ClientHandler::get_alpn() const { return alpn_; }
+
 BlockAllocator &ClientHandler::get_block_allocator() { return balloc_; }
 
 } // namespace shrpx

src/shrpx_client_handler.h

@@ -166,6 +166,9 @@ public:
   // Returns TLS SNI extension value client sent in this connection.
   StringRef get_tls_sni() const;
 
+  // Returns ALPN negotiated in this connection.
+  StringRef get_alpn() const;
+
   BlockAllocator &get_block_allocator();
 
 private:

src/shrpx_mruby_module_env.cc

@@ -198,6 +198,92 @@ mrb_value env_get_tls_client_subject_name(mrb_state *mrb, mrb_value self) {
 }
 } // namespace
 
+namespace {
+mrb_value env_get_tls_cipher(mrb_state *mrb, mrb_value self) {
+  auto data = static_cast<MRubyAssocData *>(mrb->ud);
+  auto downstream = data->downstream;
+  auto upstream = downstream->get_upstream();
+  auto handler = upstream->get_client_handler();
+  auto ssl = handler->get_ssl();
+
+  if (!ssl) {
+    return mrb_str_new_static(mrb, "", 0);
+  }
+
+  return mrb_str_new_cstr(mrb, SSL_get_cipher_name(ssl));
+}
+} // namespace
+
+namespace {
+mrb_value env_get_tls_protocol(mrb_state *mrb, mrb_value self) {
+  auto data = static_cast<MRubyAssocData *>(mrb->ud);
+  auto downstream = data->downstream;
+  auto upstream = downstream->get_upstream();
+  auto handler = upstream->get_client_handler();
+  auto ssl = handler->get_ssl();
+
+  if (!ssl) {
+    return mrb_str_new_static(mrb, "", 0);
+  }
+
+  return mrb_str_new_cstr(mrb, nghttp2::tls::get_tls_protocol(ssl));
+}
+} // namespace
+
+namespace {
+mrb_value env_get_tls_session_id(mrb_state *mrb, mrb_value self) {
+  auto data = static_cast<MRubyAssocData *>(mrb->ud);
+  auto downstream = data->downstream;
+  auto upstream = downstream->get_upstream();
+  auto handler = upstream->get_client_handler();
+  auto ssl = handler->get_ssl();
+
+  if (!ssl) {
+    return mrb_str_new_static(mrb, "", 0);
+  }
+
+  auto session = SSL_get_session(ssl);
+  if (!session) {
+    return mrb_str_new_static(mrb, "", 0);
+  }
+
+  unsigned int session_id_length = 0;
+  auto session_id = SSL_SESSION_get_id(session, &session_id_length);
+
+  // TODO Use template version of util::format_hex.
+  auto &balloc = downstream->get_block_allocator();
+  auto id = util::format_hex(balloc, StringRef{session_id, session_id_length});
+  return mrb_str_new(mrb, id.c_str(), id.size());
+}
+} // namespace
+
+namespace {
+mrb_value env_get_tls_session_reused(mrb_state *mrb, mrb_value self) {
+  auto data = static_cast<MRubyAssocData *>(mrb->ud);
+  auto downstream = data->downstream;
+  auto upstream = downstream->get_upstream();
+  auto handler = upstream->get_client_handler();
+  auto ssl = handler->get_ssl();
+
+  if (!ssl) {
+    return mrb_false_value();
+  }
+
+  return SSL_session_reused(ssl) ? mrb_true_value() : mrb_false_value();
+}
+} // namespace
+
+namespace {
+mrb_value env_get_alpn(mrb_state *mrb, mrb_value self) {
+  auto data = static_cast<MRubyAssocData *>(mrb->ud);
+  auto downstream = data->downstream;
+  auto upstream = downstream->get_upstream();
+  auto handler = upstream->get_client_handler();
+  auto alpn = handler->get_alpn();
+  return mrb_str_new(mrb, alpn.c_str(), alpn.size());
+}
+} // namespace
+
 void init_env_class(mrb_state *mrb, RClass *module) {
   auto env_class =
       mrb_define_class_under(mrb, module, "Env", mrb->object_class);
@@ -221,6 +307,15 @@ void init_env_class(mrb_state *mrb, RClass *module) {
                     env_get_tls_client_fingerprint, MRB_ARGS_NONE());
   mrb_define_method(mrb, env_class, "tls_client_subject_name",
                     env_get_tls_client_subject_name, MRB_ARGS_NONE());
+  mrb_define_method(mrb, env_class, "tls_cipher", env_get_tls_cipher,
+                    MRB_ARGS_NONE());
+  mrb_define_method(mrb, env_class, "tls_protocol", env_get_tls_protocol,
+                    MRB_ARGS_NONE());
+  mrb_define_method(mrb, env_class, "tls_session_id", env_get_tls_session_id,
+                    MRB_ARGS_NONE());
+  mrb_define_method(mrb, env_class, "tls_session_reused",
+                    env_get_tls_session_reused, MRB_ARGS_NONE());
+  mrb_define_method(mrb, env_class, "alpn", env_get_alpn, MRB_ARGS_NONE());
 }
 
 } // namespace mruby