Take into account virtual devices (e.g. OpenVPN tun0) when iterating network

runtime/bin/socket_macos.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_MACOS)
 
 #include <errno.h>  // NOLINT
 #include <stdio.h>  // NOLINT
 #include <stdlib.h>  // NOLINT
@@ skipping 228 matching lines @@
     *os_error = new OSError(status,
                             gai_strerror(status),
                             OSError::kGetAddressInfo);
     return false;
   }
   return true;
 }
 
 
 static bool ShouldIncludeIfaAddrs(struct ifaddrs* ifa, int lookup_family) {
+  if (ifa->ifa_addr == NULL) {
+    // OpenVPN's virtual device tun0.
+    return false;
+  }
   int family = ifa->ifa_addr->sa_family;
   if (lookup_family == family) return true;
   if (lookup_family == AF_UNSPEC &&
       (family == AF_INET || family == AF_INET6)) {
     return true;
   }
   return false;
 }
 
 
@@ skipping 132 matching lines @@
                                        IPPROTO_TCP,
                                        TCP_NODELAY,
                                        reinterpret_cast<char *>(&on),
                                        sizeof(on))) == 0;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_MACOS)