Add echo handler in app server for secure channel testing (#5236)

examples/lighting-app/linux/README.md

@@ -48,6 +48,12 @@ Raspberry Pi Desktop 20.10 (aarch64)**
 >
 >     gn gen out/debug --args='chip_bypass_rendezvous=false'
 
+> If you want to test Echo protocol, please disable Rendezvous and enable Echo
+> handler
+>
+>     gn gen out/debug --args='chip_bypass_rendezvous=true chip_app_use_echo=true'
+>     ninja -C out/debug
+
 -   Prerequisites
 
     1. A Raspberry Pi 4 board

src/app/common_flags.gni

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 declare_args() {
-  # Temporary flag for new interaction model engine, set it to true to enable
+  # Temporary flag for interaction model and echo protocols, set it to true to enable
+  chip_app_use_echo = false
   chip_app_use_interaction_model = false
 }

src/app/server/BUILD.gn

@@ -22,13 +22,19 @@ config("server_config") {
     defines += [ "CHIP_APP_USE_INTERACTION_MODEL" ]
   }
 
+  if (chip_app_use_echo) {
+    defines += [ "CHIP_APP_USE_ECHO" ]
+  }
+
   include_dirs = [ "." ]
 }
 
 static_library("server") {
   output_name = "libCHIPAppServer"
 
   sources = [
+    "EchoHandler.cpp",
+    "EchoHandler.h",
     "Mdns.cpp",
     "Mdns.h",
     "QRCodeUtil.cpp",
@@ -46,6 +52,7 @@ static_library("server") {
     "${chip_root}/src/lib/mdns",
     "${chip_root}/src/messaging",
     "${chip_root}/src/platform",
+    "${chip_root}/src/protocols",
     "${chip_root}/src/setup_payload",
     "${chip_root}/src/transport",
   ]

src/app/server/EchoHandler.cpp

@@ -0,0 +1,65 @@
+/*
+ *
+ *    Copyright (c) 2021 Project CHIP 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.
+ */
+
+/**
+ * @file
+ *   This file implements the handler for echo messages.
+ */
+
+#include <app/server/EchoHandler.h>
+
+#include <protocols/echo/Echo.h>
+#include <support/ErrorStr.h>
+
+namespace {
+
+// The EchoServer object.
+chip::Protocols::Echo::EchoServer gEchoServer;
+
+/**
+ * Callback handler when a CHIP EchoRequest is received.
+ *
+ * @param [in] ec      The exchange context holding the incoming message.
+ * @param [in] payload The buffer holding the message.  This function guarantees
+ *                     that it will free the buffer before returning.
+ *
+ */
+void HandleEchoRequestReceived(chip::Messaging::ExchangeContext * ec, chip::System::PacketBufferHandle payload)
+{
+    ChipLogProgress(AppServer, "Echo Request, len=%u ... sending response.\n", payload->DataLength());
+}
+
+} // namespace
+
+CHIP_ERROR InitEchoHandler(chip::Messaging::ExchangeManager * exchangeMgr)
+{
+    CHIP_ERROR err = CHIP_NO_ERROR;
+
+    err = gEchoServer.Init(exchangeMgr);
+    SuccessOrExit(err);
+
+    // Arrange to get a callback whenever an Echo Request is received.
+    gEchoServer.SetEchoRequestReceived(HandleEchoRequestReceived);
+
+exit:
+    if (err != CHIP_NO_ERROR)
+    {
+        ChipLogError(AppServer, "EchoServer failed, err:%s\n", chip::ErrorStr(err));
+    }
+
+    return err;
+}

src/app/server/EchoHandler.h

@@ -0,0 +1,33 @@
+/*
+ *
+ *    Copyright (c) 2021 Project CHIP 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.
+ */
+
+/**
+ * @file
+ *   This file defines the API for the handler for echo messages.
+ */
+
+#pragma once
+
+#include <messaging/ExchangeMgr.h>
+#include <system/SystemPacketBuffer.h>
+
+/**
+ * Register an unsolicited message handler for Echo protocol to be ready to process
+ * Echo messages.
+ *
+ */
+CHIP_ERROR InitEchoHandler(chip::Messaging::ExchangeManager * exchangeMgr);

src/app/server/Server.cpp

@@ -19,6 +19,7 @@
 
 #include <app/InteractionModelEngine.h>
 #include <app/server/DataModelHandler.h>
+#include <app/server/EchoHandler.h>
 #include <app/server/RendezvousServer.h>
 #include <app/server/SessionManager.h>
 
@@ -410,8 +411,8 @@ class ServerCallback : public SecureSessionMgrDelegate
     AppDelegate * mDelegate = nullptr;
 };
 
-#ifdef CHIP_APP_USE_INTERACTION_MODEL
-Messaging::ExchangeManager gExchange;
+#if defined(CHIP_APP_USE_INTERACTION_MODEL) || defined(CHIP_APP_USE_ECHO)
+Messaging::ExchangeManager gExchangeMgr;
 #endif
 ServerCallback gCallbacks;
 SecurePairingUsingTestSecret gTestPairing;
@@ -487,15 +488,23 @@ void InitServer(AppDelegate * delegate)
     err = gSessions.Init(chip::kTestDeviceNodeId, &DeviceLayer::SystemLayer, &gTransports, &gAdminPairings);
     SuccessOrExit(err);
 
-#ifdef CHIP_APP_USE_INTERACTION_MODEL
-    err = gExchange.Init(&gSessions);
-    SuccessOrExit(err);
-    err = chip::app::InteractionModelEngine::GetInstance()->Init(&gExchange);
+#if defined(CHIP_APP_USE_INTERACTION_MODEL) || defined(CHIP_APP_USE_ECHO)
+    err = gExchangeMgr.Init(&gSessions);
     SuccessOrExit(err);
 #else
     gSessions.SetDelegate(&gCallbacks);
 #endif
 
+#if defined(CHIP_APP_USE_INTERACTION_MODEL)
+    err = chip::app::InteractionModelEngine::GetInstance()->Init(&gExchangeMgr);
+    SuccessOrExit(err);
+#endif
+
+#if defined(CHIP_APP_USE_ECHO)
+    err = InitEchoHandler(&gExchangeMgr);
+    SuccessOrExit(err);
+#endif
+
     if (useTestPairing())
     {
         AdminPairingInfo * adminInfo = gAdminPairings.AssignAdminId(gNextAvailableAdminId);