[nrf toup] [nrfconnect] Enable MLDv2 join procedure for IPv6 Multicasts

This commit updates the IPv6 multicast subscription mechanism by
explicitly using the MLDv2 join procedure. This change ensures proper
registration for multicast addresses, improving reliability in multicast
communication.

Signed-off-by: Łukasz Duda <[email protected]>

src/platform/nrfconnect/ConnectivityManagerImpl.cpp

@@ -40,6 +40,13 @@
 #include <platform/internal/GenericConnectivityManagerImpl_Thread.ipp>
 #endif
 
+#if CHIP_DEVICE_CONFIG_ENABLE_WIFI
+// Temporary workaround for lack of the public Zephyr's API for MLDv2.
+// Should be removed after https://github.com/zephyrproject-rtos/zephyr/pull/79274 is merged.
+extern "C" int net_ipv6_mld_join(struct net_if *iface, const struct in6_addr *addr);
+extern "C" int net_ipv6_mld_leave(struct net_if *iface, const struct in6_addr *addr);
+#endif
+
 using namespace ::chip::Inet;
 using namespace ::chip::DeviceLayer::Internal;
 
@@ -70,19 +77,17 @@ CHIP_ERROR JoinLeaveMulticastGroup(net_if * iface, const Inet::IPAddress & addre
     // The following code should also be valid for other interface types, such as Ethernet,
     // but they are not officially supported, so for now enable it for Wi-Fi only.
     const in6_addr in6Addr = InetUtils::ToZephyrAddr(address);
+    int status;
 
     if (operation == UDPEndPointImplSockets::MulticastOperation::kJoin)
     {
-        net_if_mcast_addr * maddr = net_if_ipv6_maddr_add(iface, &in6Addr);
-
-        if (maddr && !net_if_ipv6_maddr_is_joined(maddr))
-        {
-            net_if_ipv6_maddr_join(iface, maddr);
-        }
+        status = net_ipv6_mld_join(iface, &in6Addr);
+        VerifyOrReturnError((status == 0 || status == -EALREADY), System::MapErrorZephyr(status));
     }
     else if (operation == UDPEndPointImplSockets::MulticastOperation::kLeave)
     {
-        VerifyOrReturnError(net_if_ipv6_maddr_rm(iface, &in6Addr), CHIP_ERROR_INVALID_ADDRESS);
+        status = net_ipv6_mld_leave(iface, &in6Addr);
+        VerifyOrReturnError(status == 0, System::MapErrorZephyr(status));
     }
     else
     {