From bf6ed702db60eff477d7612e46434c3a05ccf2e1 Mon Sep 17 00:00:00 2001
From: Francis Tsui <ftsui@google.com>
Date: Tue, 6 Jan 2026 16:16:25 -0800
Subject: [PATCH] Add reg key to disable mDNS advertising.

PiperOrigin-RevId: 852976950
---
 internal/platform/implementation/windows/BUILD      |  1 +
 .../implementation/windows/wifi_lan_medium.cc       | 13 +++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/internal/platform/implementation/windows/BUILD b/internal/platform/implementation/windows/BUILD
index c81a505d..2079db10 100644
--- a/internal/platform/implementation/windows/BUILD
+++ b/internal/platform/implementation/windows/BUILD
@@ -327,6 +327,7 @@ cc_library(
     deps = [
         ":crypto",  # build_cleaner: keep
         ":network_info",
+        ":registry",
         ":scoped_wlan_memory",
         ":socket_address",
         ":string_utils",
diff --git a/internal/platform/implementation/windows/wifi_lan_medium.cc b/internal/platform/implementation/windows/wifi_lan_medium.cc
index 37361804..2b078349 100644
--- a/internal/platform/implementation/windows/wifi_lan_medium.cc
+++ b/internal/platform/implementation/windows/wifi_lan_medium.cc
@@ -48,6 +48,7 @@
 #include "internal/platform/implementation/windows/generated/winrt/Windows.Networking.Connectivity.h"
 #include "internal/platform/implementation/windows/nearby_client_socket.h"
 #include "internal/platform/implementation/windows/network_info.h"
+#include "internal/platform/implementation/windows/registry.h"
 #include "internal/platform/implementation/windows/socket_address.h"
 #include "internal/platform/implementation/windows/string_utils.h"
 #include "internal/platform/implementation/windows/utils.h"
@@ -56,6 +57,7 @@
 
 namespace nearby::windows {
 namespace {
+using ::nearby::platform::windows::Registry;
 using ::winrt::fire_and_forget;
 using ::winrt::Windows::Devices::Enumeration::DeviceInformation;
 using ::winrt::Windows::Devices::Enumeration::DeviceInformationKind;
@@ -75,6 +77,9 @@ constexpr absl::string_view kMdnsDeviceSelectorFormat =
     "AND System.Devices.Dnssd.ServiceName:=\"%s\" AND "
     "System.Devices.Dnssd.Domain:=\"local\"";
 
+constexpr absl::string_view kDisableMdnsAdvertisingRegistryValue =
+    "disable_mdns_advertising";
+
 constexpr absl::Duration kConnectTimeout = absl::Milliseconds(500);
 
 bool IsSelfInstance(IMapView<winrt::hstring, IInspectable> properties,
@@ -191,6 +196,14 @@ bool WifiLanMedium::StartAdvertising(const NsdServiceInfo& nsd_service_info) {
     return false;
   }
   service_name_ = nsd_service_info.GetServiceName();
+  if (Registry::ReadDword(Registry::Hive::kCurrentUser,
+                          Registry::Key::kNearbyShareFlags,
+                          std::string(kDisableMdnsAdvertisingRegistryValue))
+          .value_or(0) != 0) {
+    LOG(INFO) << "MDNS advertising is disabled by registry.";
+    medium_status_ |= kMediumStatusAdvertising;
+    return true;
+  }
   if (wifi_lan_mdns_.StartMdnsService(
           service_name_, nsd_service_info.GetServiceType(),
           nsd_service_info.GetPort(), nsd_service_info.GetTxtRecords())) {