Separate Rendezvous message handling from BLE session (#2418)

* Separate Rendezvous message handling from BLE session With this change, BLE handling remains in RendezvousSession and message processing independent of BLE moves to RendervousMessageHandler. * Restyled by clang-format * Use fixed-length message buffer. Co-authored-by: Restyled.io <[email protected]>
project-chip · Sep 8, 2020 · f59dcbc · f59dcbc
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Showing 3 changed files with 102 additions and 27 deletions.
diff --git a/examples/wifi-echo/server/esp32/main/RendezvousMessageHandler.cpp b/examples/wifi-echo/server/esp32/main/RendezvousMessageHandler.cpp
@@ -0,0 +1,61 @@
+/*
+ *
+ *    Copyright (c) 2020 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.
+ */
+
+#include "RendezvousMessageHandler.h"
+#include <platform/ESP32/ESP32Utils.h>
+#include <support/CodeUtils.h>
+#include <support/logging/CHIPLogging.h>
+#include <system/SystemPacketBuffer.h>
+
+using namespace ::chip;
+
+extern CHIP_ERROR SetWiFiStationProvisioning(char * ssid, char * key);
+
+CHIP_ERROR RendezvousMessageHandler::HandleMessageReceived(System::PacketBuffer * buffer)
+{
+    CHIP_ERROR err         = CHIP_NO_ERROR;
+    bool isWiFiCredentials = false;
+    char * key             = nullptr;
+    char * ssid            = nullptr;
+
+    // Pending definition of an actual message format, WiFi credentials have the form
+    // ‘::SSID:password:’, where ‘:’ can be any single ASCII character.
+    constexpr size_t maxBufferLen =
+        4 + chip::DeviceLayer::Internal::kMaxWiFiSSIDLength + chip::DeviceLayer::Internal::kMaxWiFiKeyLength;
+    char msg[maxBufferLen];
+
+    const size_t bufferLen = buffer->DataLength();
+    VerifyOrExit(bufferLen < sizeof msg, err = CHIP_ERROR_INVALID_MESSAGE_TYPE);
+    memcpy(msg, buffer->Start(), bufferLen);
+    msg[bufferLen] = 0;
+    ChipLogProgress(NetworkProvisioning, "RendezvousMessageHandler: Receive message: %s", msg);
+
+    isWiFiCredentials = ((bufferLen > 3) && (msg[0] == msg[1]) && (msg[0] == msg[bufferLen - 1]));
+    VerifyOrExit(isWiFiCredentials, err = CHIP_ERROR_INVALID_MESSAGE_TYPE);
+
+    msg[1] = 0;
+    ssid   = strtok(&msg[2], msg);
+    key    = strtok(NULL, msg);
+    VerifyOrExit(ssid && key, err = CHIP_ERROR_INVALID_MESSAGE_TYPE);
+
+    ChipLogProgress(NetworkProvisioning, "RendezvousMessageHandler: SSID: %s, key: %s", ssid, key);
+    err = SetWiFiStationProvisioning(ssid, key);
+    SuccessOrExit(err);
+
+exit:
+    return err;
+}
diff --git a/examples/wifi-echo/server/esp32/main/RendezvousSession.cpp b/examples/wifi-echo/server/esp32/main/RendezvousSession.cpp
@@ -16,15 +16,14 @@
  */
 
 #include "RendezvousSession.h"
+#include "RendezvousMessageHandler.h"
 #include <support/CodeUtils.h>
 #include <support/ErrorStr.h>
 #include <support/logging/CHIPLogging.h>
 #include <system/SystemPacketBuffer.h>
 
 using namespace ::chip;
 
-extern CHIP_ERROR SetWiFiStationProvisioning(char * ssid, char * key);
-
 BluetoothWidget * RendezvousSession::mVirtualLed;
 
 Ble::BLEEndPoint * RendezvousSession::mEndPoint = nullptr;
@@ -131,32 +130,11 @@ void RendezvousSession::HandleMessageReceived(Ble::BLEEndPoint * endPoint, Packe
     }
     else
     {
-        const size_t bufferLen = buffer->DataLength();
-        char msg[bufferLen];
-        msg[bufferLen] = 0;
-        memcpy(msg, buffer->Start(), bufferLen);
-
-        ChipLogProgress(Ble, "RendezvousSession: Receive message: %s", msg);
-
-        if ((bufferLen > 3) && (msg[0] == msg[1]) && (msg[0] == msg[bufferLen - 1]))
-        {
-            // WiFi credentials, of the form ‘::SSID:password:’, where ‘:’ can be any single ASCII character.
-            msg[1]      = 0;
-            char * ssid = strtok(&msg[2], msg);
-            char * key  = strtok(NULL, msg);
-            if (ssid && key)
-            {
-                ChipLogProgress(Ble, "RendezvousSession: SSID: %s, key: %s", ssid, key);
-                SetWiFiStationProvisioning(ssid, key);
-            }
-            else
-            {
-                ChipLogError(Ble, "RendezvousSession: SSID: %p, key: %p", ssid, key);
-            }
-        }
-        else
+        // When paired, offer the RendezvousMessageHandler a chance to process the message.
+        CHIP_ERROR err = RendezvousMessageHandler::HandleMessageReceived(buffer);
+        if (err == CHIP_ERROR_INVALID_MESSAGE_TYPE)
         {
-            // Echo.
+            // If the handler did not recognize the message, treat it as an echo request.
             mEndPoint->Send(buffer);
         }
     }

diff --git a/examples/wifi-echo/server/esp32/main/include/RendezvousMessageHandler.h b/examples/wifi-echo/server/esp32/main/include/RendezvousMessageHandler.h
@@ -0,0 +1,36 @@
+/*
+ *
+ *    Copyright (c) 2020 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.
+ */
+
+#ifndef _RENDEZVOUS_MESSAGE_HANDLER_H
+#define _RENDEZVOUS_MESSAGE_HANDLER_H
+
+#include <core/CHIPError.h>
+#include <platform/CHIPDeviceLayer.h>
+
+using namespace ::chip;
+
+class RendezvousMessageHandler
+{
+public:
+    // Handle a rendezvous message. Returns:
+    // - CHIP_NO_ERROR if the message was handled successfully.
+    // - CHIP_ERROR_INVALID_MESSAGE_TYPE if the message was not recognized.
+    // - Some other error encountered processing a specific message type.
+    static CHIP_ERROR HandleMessageReceived(System::PacketBuffer * buffer);
+};
+
+#endif // _RENDEZVOUS_MESSAGE_HANDLER_H