ios: use NetworkPathMonitor

SCNetworkReachabilityCreateWithAddress is deprecated for some time.

src/ios/YassAppDelegate.mm

@@ -52,6 +52,7 @@ @implementation YassAppDelegate {
 - (BOOL)application:(UIApplication*)application
     didFinishLaunchingWithOptions:(NSDictionary<UIApplicationLaunchOptionsKey, id>*)launchOptions {
   state_ = STOPPED;
+  initNetworkPathMonitor();
   [self didDefaultsChanged:nil];
   [[NSNotificationCenter defaultCenter] addObserver:self
                                            selector:@selector(didDefaultsChanged:)

src/ios/utils.cpp

@@ -3,7 +3,6 @@
 
 #include "ios/utils.h"
 
-#include <SystemConfiguration/SCNetworkReachability.h>
 #include <arpa/inet.h>
 #include <ifaddrs.h>
 #include <net/if.h>
@@ -14,31 +13,6 @@
 
 using json = nlohmann::json;
 
-bool connectedToNetwork() {
-  // Create zero addy
-  struct sockaddr_in zeroAddress;
-  bzero(&zeroAddress, sizeof(zeroAddress));
-  zeroAddress.sin_len = sizeof(zeroAddress);
-  zeroAddress.sin_family = AF_INET;
-
-  // Recover reachability flags
-  SCNetworkReachabilityRef defaultRouteReachability =
-      SCNetworkReachabilityCreateWithAddress(NULL, (struct sockaddr*)&zeroAddress);
-  SCNetworkReachabilityFlags flags;
-
-  Boolean didRetrieveFlags = SCNetworkReachabilityGetFlags(defaultRouteReachability, &flags);
-  CFRelease(defaultRouteReachability);
-
-  if (!didRetrieveFlags) {
-    return false;
-  }
-
-  Boolean isReachable = flags & kSCNetworkFlagsReachable;
-  Boolean needsConnection = flags & kSCNetworkFlagsConnectionRequired;
-
-  return (isReachable && !needsConnection) ? true : false;
-}
-
 std::string serializeTelemetryJson(uint64_t total_rx_bytes, uint64_t total_tx_bytes) {
   json j;
   j["total_rx_bytes"] = total_rx_bytes;

src/ios/utils.h

@@ -7,7 +7,11 @@
 #include <string_view>
 #include <vector>
 
+void initNetworkPathMonitor();
+void deinitNetworkPathMonitor();
+
 bool connectedToNetwork();
+
 std::string serializeTelemetryJson(uint64_t total_rx_bytes, uint64_t total_tx_bytes);
 bool parseTelemetryJson(std::string_view resp, uint64_t* total_rx_bytes, uint64_t* total_tx_bytes);
 

src/ios/utils.mm

@@ -3,4 +3,71 @@
 
 #include "ios/utils.h"
 
-// PLACE HOLDER FOR Objective-C++ Code
+#include <atomic>
+#include <thread>
+
+#include <Network/Network.h>
+
+#include "core/logging.hpp"
+
+static std::atomic<bool> connectedNetwork;
+static dispatch_queue_t monitorQueue;
+static nw_path_monitor_t monitor;
+static std::once_flag initFlag;
+
+// https://forums.developer.apple.com/forums/thread/105822
+void initNetworkPathMonitor() {
+  DCHECK(!monitor);
+
+  std::call_once(initFlag, []() {
+    dispatch_queue_attr_t attrs = dispatch_queue_attr_make_with_qos_class(DISPATCH_QUEUE_SERIAL, QOS_CLASS_UTILITY,
+                                                                          DISPATCH_QUEUE_PRIORITY_DEFAULT);
+    monitorQueue = dispatch_queue_create("it.gui.yass.network-monitor", attrs);
+  });
+
+  // monitor = nw_path_monitor_create_with_type(nw_interface_type_wifi);
+  monitor = nw_path_monitor_create();
+  nw_path_monitor_set_queue(monitor, monitorQueue);
+  if (@available(iOS 14, *)) {
+    nw_path_monitor_prohibit_interface_type(monitor, nw_interface_type_loopback);
+  }
+  nw_path_monitor_set_update_handler(monitor, ^(nw_path_t _Nonnull path) {
+    nw_path_status_t status = nw_path_get_status(path);
+    // Determine the active interface, but how?
+    switch (status) {
+      case nw_path_status_invalid: {
+        // Network path is invalid
+        connectedNetwork = false;
+        break;
+      }
+      case nw_path_status_satisfied: {
+        // Network is usable
+        connectedNetwork = true;
+        break;
+      }
+      case nw_path_status_satisfiable: {
+        // Network may be usable
+        connectedNetwork = false;
+        break;
+      }
+      case nw_path_status_unsatisfied: {
+        // Network is not usable
+        connectedNetwork = false;
+        break;
+      }
+    }
+  });
+
+  nw_path_monitor_start(monitor);
+}
+
+void deinitNetworkPathMonitor() {
+  DCHECK(monitor);
+
+  nw_path_monitor_cancel(monitor);
+  monitor = nw_path_monitor_t();
+}
+
+bool connectedToNetwork() {
+  return connectedNetwork;
+}