WebSocket as default socket provider

Summary:
This change makes WebSockets the default for Flipper on iOS.

Having said that, we are introducing some logic to deal with clients connecting to older Flipper Desktop versions.

The mobile client will first attempt to connect via WebSocket with the Desktop. This connection can either be secure or insecure. If that fails, it will attempt to connect via RSocket.

Connection failure logic:
The mobile client will attempt to connect up-to 3 times via a WebSocket. If it fails to connect, then the socket provider is switched to RSocket.

As before, the mobile client will attempt to connect up-to 3 times via a RSocket. If it fails to connect, then the socket provider is switched back to WebSocket.

Process repeats until a successful connection is established.

Some logs that can be seen from iOS:

   2021-09-15 14:31:51.193503+0100 Sample[92026:92107440] [] nw_protocol_get_quic_image_block_invoke dlopen libquic failed
   2021-09-15 14:31:51.878257+0100 Sample[92026:92107440] [connection] nw_socket_handle_socket_event [C1.1:1] Socket SO_ERROR [61: Connection refused]
   2021-09-15 14:31:52.553729+0100 Sample[92026:92107440] [connection] nw_socket_handle_socket_event [C1.2:1] Socket SO_ERROR [61: Connection refused]
   2021-09-15 14:31:52.899511+0100 Sample[92026:92107442] [connection] nw_connection_get_connected_socket [C1] Client called nw_connection_get_connected_socket on unconnected nw_connection
   2021-09-15 14:31:52.899664+0100 Sample[92026:92107442] TCP Conn 0x600001d384d0 Failed : error 0:61 [61]
   2021-09-15 14:31:57.120120+0100 Sample[92026:92107439] [connection] nw_socket_handle_socket_event [C2.1:1] Socket SO_ERROR [61: Connection refused]
   2021-09-15 14:31:57.141785+0100 Sample[92026:92107439] [connection] nw_socket_handle_socket_event [C2.2:1] Socket SO_ERROR [61: Connection refused]
   2021-09-15 14:31:57.151604+0100 Sample[92026:92107483] [connection] nw_connection_get_connected_socket [C2] Client called nw_connection_get_connected_socket on unconnected nw_connection
   2021-09-15 14:31:57.154312+0100 Sample[92026:92107483] TCP Conn 0x600001d7c0b0 Failed : error 0:61 [61]
   2021-09-15 14:31:59.206079+0100 Sample[92026:92107483] [connection] nw_socket_handle_socket_event [C3.1:1] Socket SO_ERROR [61: Connection refused]
   2021-09-15 14:31:59.236824+0100 Sample[92026:92107483] [connection] nw_socket_handle_socket_event [C3.2:1] Socket SO_ERROR [61: Connection refused]
   2021-09-15 14:31:59.251927+0100 Sample[92026:92107439] [connection] nw_connection_get_connected_socket [C3] Client called nw_connection_get_connected_socket on unconnected nw_connection
   2021-09-15 14:31:59.255963+0100 Sample[92026:92107439] TCP Conn 0x600001d1c210 Failed : error 0:61 [61]
   2021-09-15 14:32:01.291303+0100 Sample[92026:92107439] [connection] nw_socket_handle_socket_event [C4.1:1] Socket SO_ERROR [61: Connection refused]
   2021-09-15 14:32:01.312406+0100 Sample[92026:92107439] [connection] nw_socket_handle_socket_event [C4.2:1] Socket SO_ERROR [61: Connection refused]
   2021-09-15 14:32:01.323099+0100 Sample[92026:92107483] [connection] nw_connection_get_connected_socket [C4] Client called nw_connection_get_connected_socket on unconnected nw_connection
   2021-09-15 14:32:01.326028+0100 Sample[92026:92107483] TCP Conn 0x600001d7c0b0 Failed : error 0:61 [61]
   flipper: Failed to connect with the current socket provider
   flipper: Use legacy socket provider
   flipper: FlipperClient::onConnected

Reviewed By: passy

Differential Revision: D30900471

fbshipit-source-id: 7c242ad71306803b050d0174fc22696bb74fdba5

iOS/FlipperKit/FlipperClient.mm

@@ -107,8 +107,8 @@ using WrapperPlugin = facebook::flipper::FlipperCppWrapperPlugin;
       _cppClient = facebook::flipper::FlipperClient::instance();
 
       // To switch to a websocket provider, uncomment the line below.
-      // facebook::flipper::FlipperSocketProvider::setDefaultProvider(
-      //     std::make_unique<facebook::flipper::FlipperWebSocketProvider>());
+      facebook::flipper::FlipperSocketProvider::setDefaultProvider(
+          std::make_unique<facebook::flipper::FlipperWebSocketProvider>());
 
     } catch (const std::system_error& e) {
       // Probably ran out of disk space.

iOS/FlipperKit/FlipperPlatformWebSocket.mm

@@ -195,7 +195,16 @@ static constexpr int connectionKeepaliveSeconds = 10;
 }
 
 - (void)webSocket:(SRWebSocket*)webSocket didFailWithError:(NSError*)error {
+  /** Check for the error domain and code. Need to filter out SSL handshake
+    errors and dispatch them accordingly. CFNetwork SSLHandshake failed:
+    - Domain: NSOSStatusErrorDomain
+    - Code: -9806
+   */
+  if ([[error domain] isEqual:NSOSStatusErrorDomain] && [error code] == -9806) {
+    _eventHandler(facebook::flipper::SocketEvent::SSL_ERROR);
+  } else {
     _eventHandler(facebook::flipper::SocketEvent::ERROR);
+  }
   _socket = nil;
 }
 

iOS/FlipperKit/FlipperWebSocket.mm

@@ -154,6 +154,17 @@ bool FlipperWebSocket::connect(FlipperConnectionManager* manager) {
       fullfilled = true;
       if (event == SocketEvent::OPEN) {
         promise.set_value(true);
+      } else if (event == SocketEvent::SSL_ERROR) {
+        try {
+          promise.set_exception(
+              std::make_exception_ptr(folly::AsyncSocketException(
+                  folly::AsyncSocketException::SSL_ERROR,
+                  "SSL handshake failed")));
+        } catch (...) {
+          // set_exception() may throw an exception
+          // In that case, just set the value to false.
+          promise.set_value(false);
+        }
       } else {
         promise.set_value(false);
       }

xplat/Flipper/FlipperConnectionManagerImpl.cpp

@@ -31,6 +31,10 @@ static constexpr int reconnectIntervalSeconds = 2;
 // To be bumped for every core platform interface change.
 static constexpr int sdkVersion = 4;
 
+#ifdef __APPLE__
+static constexpr int maxFailedSocketConnectionAttempts = 3;
+#endif
+
 using namespace folly;
 
 namespace facebook {
@@ -64,6 +68,10 @@ class ConnectionEvents {
             impl->callbacks_->onConnected();
           }
           break;
+        case SocketEvent::SSL_ERROR:
+          // SSL errors are not handled as a connection event
+          // on this handler.
+          break;
         case SocketEvent::CLOSE:
         case SocketEvent::ERROR:
           if (!impl->isOpen_)
@@ -91,6 +99,8 @@ FlipperConnectionManagerImpl::FlipperConnectionManagerImpl(
       flipperState_(state),
       insecurePort(config.insecurePort),
       securePort(config.securePort),
+      altInsecurePort(config.altInsecurePort),
+      altSecurePort(config.altSecurePort),
       flipperEventBase_(config.callbackWorker),
       connectionEventBase_(config.connectionWorker),
       contextStore_(contextStore),
@@ -190,8 +200,8 @@ void FlipperConnectionManagerImpl::startSync() {
 }
 
 bool FlipperConnectionManagerImpl::connectAndExchangeCertificate() {
-  auto endpoint =
-      FlipperConnectionEndpoint(deviceData_.host, insecurePort, false);
+  auto port = useLegacySocketProvider ? insecurePort : altInsecurePort;
+  auto endpoint = FlipperConnectionEndpoint(deviceData_.host, port, false);
 
   int medium = certProvider_ != nullptr
       ? certProvider_->getCertificateExchangeMedium()
@@ -213,6 +223,7 @@ bool FlipperConnectionManagerImpl::connectAndExchangeCertificate() {
   connectionIsTrusted_ = false;
 
   if (!newClient->connect(this)) {
+    reevaluateSocketProvider();
     connectingInsecurely->fail("Failed to connect");
     return false;
   }
@@ -229,7 +240,8 @@ bool FlipperConnectionManagerImpl::connectAndExchangeCertificate() {
 }
 
 bool FlipperConnectionManagerImpl::connectSecurely() {
-  auto endpoint = FlipperConnectionEndpoint(deviceData_.host, securePort, true);
+  auto port = useLegacySocketProvider ? securePort : altSecurePort;
+  auto endpoint = FlipperConnectionEndpoint(deviceData_.host, port, true);
 
   int medium = certProvider_ != nullptr
       ? certProvider_->getCertificateExchangeMedium()
@@ -276,6 +288,7 @@ bool FlipperConnectionManagerImpl::connectSecurely() {
   connectionIsTrusted_ = true;
 
   if (!newClient->connect(this)) {
+    reevaluateSocketProvider();
     connectingSecurely->fail("Failed to connect");
     return false;
   }
@@ -456,6 +469,33 @@ void FlipperConnectionManagerImpl::sendLegacyCertificateRequest(
   });
 }
 
+/**
+    Check for the maximum number of failed socket connection attempts.
+    If exceeded, then swap the default socket provider. If the maximum
+    number of failed attempts is reached again, swap again the socket provider.
+
+    WebSocket -> RSocket -> WebSocket -> ...
+ */
+void FlipperConnectionManagerImpl::reevaluateSocketProvider() {
+#ifdef __APPLE__
+  if (failedSocketConnectionAttempts < maxFailedSocketConnectionAttempts) {
+    ++failedSocketConnectionAttempts;
+  } else {
+    log("Failed to connect with the current socket provider");
+    failedSocketConnectionAttempts = 0;
+    useLegacySocketProvider = !useLegacySocketProvider;
+
+    if (useLegacySocketProvider) {
+      log("Use legacy socket provider");
+      FlipperSocketProvider::shelveDefault();
+    } else {
+      log("Use websocket provider");
+      FlipperSocketProvider::unshelveDefault();
+    }
+  }
+#endif
+}
+
 bool FlipperConnectionManagerImpl::isRunningInOwnThread() {
   return flipperEventBase_->isInEventBaseThread();
 }

xplat/Flipper/FlipperConnectionManagerImpl.h

@@ -61,6 +61,8 @@ class FlipperConnectionManagerImpl : public FlipperConnectionManager {
   std::shared_ptr<FlipperState> flipperState_;
   int insecurePort;
   int securePort;
+  int altInsecurePort;
+  int altSecurePort;
 
   folly::EventBase* flipperEventBase_;
   folly::EventBase* connectionEventBase_;
@@ -71,6 +73,14 @@ class FlipperConnectionManagerImpl : public FlipperConnectionManager {
   bool certificateExchangeCompleted_ = false;
 
   int failedConnectionAttempts_ = 0;
+  int failedSocketConnectionAttempts = 0;
+
+#ifdef __APPLE__
+  bool useLegacySocketProvider = false;
+#else
+  bool useLegacySocketProvider = true;
+#endif
+
   std::shared_ptr<ConnectionContextStore> contextStore_;
   std::shared_ptr<FlipperConnectionManagerWrapper> implWrapper_;
 
@@ -81,6 +91,7 @@ class FlipperConnectionManagerImpl : public FlipperConnectionManager {
   void requestSignedCertFromFlipper();
   bool isRunningInOwnThread();
   void sendLegacyCertificateRequest(folly::dynamic message);
+  void reevaluateSocketProvider();
   std::string getDeviceId();
 };
 

xplat/Flipper/FlipperSocketProvider.cpp

@@ -38,8 +38,10 @@ class FlipperDefaultSocketProvider : public FlipperSocketProvider {
 std::unique_ptr<FlipperSocketProvider> FlipperSocketProvider::provider_ =
     std::make_unique<FlipperDefaultSocketProvider>();
 
-std::unique_ptr<FlipperSocket> FlipperSocketProvider::socketCreate(
+std::unique_ptr<FlipperSocketProvider> FlipperSocketProvider::shelvedProvider_ =
+    nullptr;
 
+std::unique_ptr<FlipperSocket> FlipperSocketProvider::socketCreate(
     FlipperConnectionEndpoint endpoint,
     std::unique_ptr<FlipperSocketBasePayload> payload,
     folly::EventBase* eventBase) {
@@ -63,5 +65,14 @@ void FlipperSocketProvider::setDefaultProvider(
   provider_ = std::move(provider);
 }
 
+void FlipperSocketProvider::shelveDefault() {
+  shelvedProvider_ = std::move(provider_);
+  provider_ = std::make_unique<FlipperDefaultSocketProvider>();
+}
+
+void FlipperSocketProvider::unshelveDefault() {
+  provider_ = std::move(shelvedProvider_);
+}
+
 } // namespace flipper
 } // namespace facebook

xplat/Flipper/FlipperSocketProvider.h

@@ -66,8 +66,19 @@ class FlipperSocketProvider {
   static void setDefaultProvider(
       std::unique_ptr<FlipperSocketProvider> provider);
 
+  /**
+    Shelves the current default socket provider and promotes the internal
+    socket provider as default.
+   */
+  static void shelveDefault();
+  /**
+    Restores a previously shelved socket provider.
+   */
+  static void unshelveDefault();
+
  private:
   static std::unique_ptr<FlipperSocketProvider> provider_;
+  static std::unique_ptr<FlipperSocketProvider> shelvedProvider_;
 };
 
 } // namespace flipper

xplat/Flipper/FlipperTransportTypes.h

@@ -15,11 +15,7 @@ namespace flipper {
 /**
   SocketEvent defines the socket states used by Flipper.
  */
-enum class SocketEvent : int {
-  OPEN,
-  CLOSE,
-  ERROR,
-};
+enum class SocketEvent : int { OPEN, CLOSE, ERROR, SSL_ERROR };
 
 /**
  Defines a socket event handler. Used to notify changes in socket state.