Add flag for sending hotspot address candidates.

PiperOrigin-RevId: 830628854

internal/platform/flags/nearby_platform_feature_flags.h

@@ -53,6 +53,10 @@ constexpr auto kWifiHotspotConnectionIntervalMillis =
 constexpr auto kWifiHotspotConnectionTimeoutMillis =
     flags::Flag<int64_t>(kConfigPackage, "45415888", 10000);
 
+// Enable/Disable use of address candidates for hotspot upgrade in Windows.
+constexpr auto kEnableHotspotAddressCandidates =
+    flags::Flag<bool>(kConfigPackage, "45739567", false);
+
 // Enable/Disable DHCP renewal when connecting to hotspot.
 constexpr auto kEnableHotspotDhcpRenew =
     flags::Flag<bool>(kConfigPackage, "45731858", false);

internal/platform/implementation/windows/wifi_hotspot_medium.cc

@@ -409,6 +409,14 @@ bool WifiHotspotMedium::ConnectWifiHotspot(
 
     // Make sure IP address is ready.
     bool has_address = false;
+    bool has_ipv6_candidates = false;
+    for (const auto& address_candidate :
+         hotspot_credentials.GetAddressCandidates()) {
+      if (address_candidate.address.size() == 16) {
+        has_ipv6_candidates = true;
+        break;
+      }
+    }
     int64_t ip_address_max_retries = NearbyFlags::GetInstance().GetInt64Flag(
         platform::config_package_nearby::nearby_platform_feature::
             kWifiHotspotCheckIpMaxRetries);
@@ -425,7 +433,7 @@ bool WifiHotspotMedium::ConnectWifiHotspot(
     for (int i = 0; i < ip_address_max_retries; i++) {
       LOG(INFO) << "Check IP address at attempt " << i;
 
-      if (wifi_hotspot_native_.HasAssignedAddress()) {
+      if (wifi_hotspot_native_.HasAssignedAddress(has_ipv6_candidates)) {
         has_address = true;
         break;
       }

internal/platform/implementation/windows/wifi_hotspot_native.cc

@@ -393,7 +393,7 @@ bool WifiHotspotNative::RestoreWifiProfile() {
   return ConnectToWifiNetworkInternal(interface_guid, backup_profile_name_);
 }
 
-bool WifiHotspotNative::HasAssignedAddress() {
+bool WifiHotspotNative::HasAssignedAddress(bool include_ipv6) {
   if (!network_info_.Refresh()) {
     return false;
   }
@@ -408,6 +408,11 @@ bool WifiHotspotNative::HasAssignedAddress() {
     if (interface.luid.Value != luid.Value) {
       continue;
     }
+    if (include_ipv6) {
+      if (!interface.ipv6_addresses.empty()) {
+        return true;
+      }
+    }
     for (const auto& address : interface.ipv4_addresses) {
       DCHECK(address.ss_family == AF_INET);
       const sockaddr_in* ipv4_address =

internal/platform/implementation/windows/wifi_hotspot_native.h

@@ -47,8 +47,10 @@ class WifiHotspotNative {
 
   bool RestoreWifiProfile() ABSL_LOCKS_EXCLUDED(mutex_);
 
-  // Returns true if the interface has a non local scoped IPv4 address.
-  bool HasAssignedAddress();
+  // Returns true if the interface has required IP address assigned.
+  // If `include_ipv6` is false, check for non local scoped IPv4 address only.
+  // Otherwise, check for any IPv6 address or non local scoped IPv4 address.
+  bool HasAssignedAddress(bool include_ipv6);
   bool RenewIpv4Address() const;
   // Return the interface index of the wifi interface used to connect to the
   // hotspot.

internal/platform/implementation/windows/wifi_hotspot_server_socket.cc

@@ -34,6 +34,7 @@
 #include "internal/platform/implementation/windows/generated/winrt/Windows.Foundation.Collections.h"
 #include "internal/platform/implementation/windows/generated/winrt/Windows.Networking.Connectivity.h"
 #include "internal/platform/implementation/windows/generated/winrt/Windows.Networking.Sockets.h"
+#include "internal/platform/implementation/windows/network_info.h"
 #include "internal/platform/implementation/windows/socket_address.h"
 #include "internal/platform/implementation/windows/utils.h"
 #include "internal/platform/implementation/windows/wifi_hotspot_server_socket.h"
@@ -87,18 +88,53 @@ void WifiHotspotServerSocket::PopulateHotspotCredentials(
                     "addresses configured on computer.";
     return;
   }
-  std::vector<char> hotspot_ipaddr_bytes;
-  uint32_t address_int = inet_addr(hotspot_ipaddr.c_str());
-  if (address_int != INADDR_NONE) {
-    hotspot_ipaddr_bytes.resize(4);
-    std::memcpy(hotspot_ipaddr_bytes.data(),
-                reinterpret_cast<char*>(&address_int), 4);
+  bool use_address_candidates = NearbyFlags::GetInstance().GetBoolFlag(
+    platform::config_package_nearby::nearby_platform_feature::
+        kEnableHotspotAddressCandidates);
+
+  if (!use_address_candidates) {
+    std::vector<char> hotspot_ipaddr_bytes;
+    uint32_t address_int = inet_addr(hotspot_ipaddr.c_str());
+    if (address_int != INADDR_NONE) {
+      hotspot_ipaddr_bytes.resize(4);
+      std::memcpy(hotspot_ipaddr_bytes.data(),
+                  reinterpret_cast<char*>(&address_int), 4);
+    }
+    ServiceAddress service_address = {
+        .address = hotspot_ipaddr_bytes,
+        .port = static_cast<uint16_t>(GetPort()),
+    };
+    hotspot_credentials.SetAddressCandidates({service_address});
+    return;
   }
-  ServiceAddress service_address = {
-    .address = hotspot_ipaddr_bytes,
-    .port = static_cast<uint16_t>(GetPort()),
-  };
-  hotspot_credentials.SetAddressCandidates({service_address});
+  std::vector<ServiceAddress> service_addresses;
+  for (const auto& interface : NetworkInfo::GetNetworkInfo().GetInterfaces()) {
+    if (interface.type == InterfaceType::kWifiHotspot) {
+      LOG(INFO) << "Found Wifi Hotspot interface, index: " << interface.index;
+      for (const auto& ipaddress : interface.ipv6_addresses) {
+        const sockaddr_in6* ipv6_address =
+            reinterpret_cast<const sockaddr_in6*>(&ipaddress);
+        service_addresses.push_back(ServiceAddress{
+            .address = std::vector<char>(ipv6_address->sin6_addr.u.Byte,
+                                         ipv6_address->sin6_addr.u.Byte + 16),
+            .port = static_cast<uint16_t>(GetPort()),
+        });
+      }
+      for (const auto& ipaddress : interface.ipv4_addresses) {
+        const sockaddr_in* ipv4_address =
+            reinterpret_cast<const sockaddr_in*>(&ipaddress);
+        service_addresses.push_back(ServiceAddress{
+            .address = {ipv4_address->sin_addr.S_un.S_un_b.s_b1,
+                        ipv4_address->sin_addr.S_un.S_un_b.s_b2,
+                        ipv4_address->sin_addr.S_un.S_un_b.s_b3,
+                        ipv4_address->sin_addr.S_un.S_un_b.s_b4},
+            .port = static_cast<uint16_t>(GetPort()),
+        });
+      }
+      break;
+    }
+  }
+  hotspot_credentials.SetAddressCandidates(std::move(service_addresses));
 }
 
 bool WifiHotspotServerSocket::Listen(int port, bool dual_stack) {