Implement network hotplug notifier for macOS

CMakeLists.txt

@@ -46,15 +46,19 @@ if(APPLE)
   endif()
   set(ZEROCONF_FILES
     zeroconf/mdnspublisher-dnssd.mm
+    zeroconf/networkhotplugnotifier-macos.mm
   )
   set(ZEROCONF_LIBS
     "-lobjc"
+    "-framework Foundation"
     "-framework IOKit"
     "-framework CFNetwork"
+    "-framework CoreFoundation"
   )
 else()
   set(ZEROCONF_FILES
     zeroconf/mdnspublisher-avahi.cpp
+    zeroconf/networkhotplugnotifier.cpp
   )
   set(ZEROCONF_LIBS
     avahi-client
@@ -85,7 +89,6 @@ add_executable(${PROJECT_NAME}
     imageformats/pngencoder.cpp
     zeroconf/mdnspublisher.cpp
     zeroconf/hotplugnotifier.cpp
-    zeroconf/networkhotplugnotifier.cpp
     ${ZEROCONF_FILES}
 )
 if(CMAKE_SYSTEM_NAME STREQUAL FreeBSD)

zeroconf/networkhotplugnotifier-macos.mm

@@ -0,0 +1,98 @@
+/*
+AirSane Imaging Daemon
+Copyright (C) 2018-2023 Simul Piscator
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "networkhotplugnotifier.h"
+
+#import <Foundation/Foundation.h>
+#import <SystemConfiguration/SystemConfiguration.h>
+
+#include <iostream>
+#include <vector>
+#include <thread>
+#include <atomic>
+
+#include <string.h>
+
+struct NetworkHotplugNotifier::Private
+{
+  std::thread mThread;
+  NetworkHotplugNotifier* mpNotifier;
+  std::atomic<CFRunLoopRef> mRunLoop{NULL};
+  std::atomic<bool> mTerminate{false};
+
+  Private(NetworkHotplugNotifier* pNotifier)
+  : mpNotifier(pNotifier)
+  {
+    mTerminate = false;
+    mThread = std::thread([this]() { hotplugThread(); });
+  }
+
+  ~Private()
+  {
+    CFRunLoopRef runLoop = NULL;
+    while (!runLoop)
+      runLoop = mRunLoop;
+    mTerminate = true;
+    ::CFRunLoopStop(runLoop);
+    mThread.join();
+  }
+
+  void hotplugThread()
+  {
+    mRunLoop = ::CFRunLoopGetCurrent();
+
+    NSArray *SCMonitoringInterfacePatterns = @[@"State:/Network/Global/IPv[46]"];
+    @autoreleasepool {
+        SCDynamicStoreContext ctx = {0};
+        ctx.info = this;
+        ::SCDynamicStoreRef dsr = ::SCDynamicStoreCreate(NULL, CFSTR("network_interface_detector"), &notificationCallback, &ctx);
+        ::SCDynamicStoreSetNotificationKeys(dsr, NULL, (CFArrayRef)::CFBridgingRetain(SCMonitoringInterfacePatterns));
+        ::CFRunLoopAddSource(::CFRunLoopGetCurrent(), ::SCDynamicStoreCreateRunLoopSource(NULL, dsr, 0), kCFRunLoopDefaultMode);
+        while (!mTerminate && [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]])
+            ;
+    }
+  }
+
+  static void notificationCallback(SCDynamicStoreRef store, CFArrayRef changedKeys, void*  info)
+  {
+#if 0
+      @autoreleasepool {
+          CFIndex count = CFArrayGetCount(changedKeys);
+          for (CFIndex i = 0; i < count; ++i) {
+            CFStringRef key = (CFStringRef)::CFArrayGetValueAtIndex(changedKeys, i);
+            NSLog(@"Key \"%@\" was changed", key);
+            CFPropertyListRef ref = ::SCDynamicStoreCopyValue(store, key);
+            NSDictionary* dict = (NSDictionary*)::CFBridgingRelease(ref);
+            NSLog(@"Value %@", dict);
+          }
+      }
+#endif
+
+      auto p = static_cast<Private*>(info);
+      p->mpNotifier->onHotplugEvent(addressChange);
+  }
+};
+
+NetworkHotplugNotifier::NetworkHotplugNotifier()
+  : p(new Private(this))
+{}
+
+NetworkHotplugNotifier::~NetworkHotplugNotifier()
+{
+  delete p;
+}

zeroconf/networkhotplugnotifier.cpp

@@ -22,7 +22,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <vector>
 #include <thread>
 
-#if !__APPLE__
 #include <poll.h>
 #include <unistd.h>
 #include <netinet/in.h>
@@ -34,7 +33,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <linux/rtnetlink.h>
 #endif
 #include <net/if.h>
-#endif // !__APPLE__
 
 #include <string.h>
 
@@ -47,7 +45,6 @@ struct NetworkHotplugNotifier::Private
   Private(NetworkHotplugNotifier* pNotifier)
   : mpNotifier(pNotifier), mPipeWriteFd(-1), mPipeReadFd(-1)
   {
-#if !__APPLE__
     int fds[2];
     if (::pipe(fds) < 0) {
         std::cerr << "Could not create socket pair " 
@@ -57,23 +54,19 @@ struct NetworkHotplugNotifier::Private
     mPipeReadFd = fds[0];
     mPipeWriteFd = fds[1];
     mThread = std::thread([this]() { hotplugThread(); });
-#endif // !__APPLE__
   }
 
   ~Private()
   {
-#if !__APPLE__
     char c = '0';
     ::write(mPipeWriteFd, &c, 1);
     mThread.join();
     ::close(mPipeWriteFd);
     ::close(mPipeReadFd);
-#endif // !__APPLE__
   }
 
   void hotplugThread()
   {
-#if !__APPLE__
     int sock = ::socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
     if (sock < 0) {
       std::cerr << "Could not create netlink socket: "
@@ -119,7 +112,6 @@ struct NetworkHotplugNotifier::Private
         }
       }
     }
-#endif // !__APPLE__
   }
 };
 

zeroconf/networkhotplugnotifier.h

@@ -34,6 +34,7 @@ class NetworkHotplugNotifier
     other,
     addressArrived,
     addressLeft,
+    addressChange,
   };
   virtual void onHotplugEvent(Event) {}