From 2474cc54e30188d9fcc9067ed356df27a020a93b Mon Sep 17 00:00:00 2001
From: Jimi Chen <jimictw@google.com>
Date: Wed, 4 Jun 2025 13:54:44 +0000
Subject: [PATCH] Use multicast socket for group membership

Replace `ip addr` command with `multicastSocket` to join multicast groups.
This change improves robustness and directly leverages Java's networking capabilities for multicast management.

Flag: EXEMPT mainline
Bug: 419423721
Test: atest CtsConnectivityMultiDevicesTestCases:ApfV6Test
Change-Id: I2c941594985d98f86a4a91c9c9cd425eb75e8e97
---
 tests/cts/multidevices/apfv6_test.py          | 18 ++-----
 .../ConnectivityMultiDevicesSnippet.kt        | 51 +++++++++++++++++++
 2 files changed, 55 insertions(+), 14 deletions(-)

diff --git a/tests/cts/multidevices/apfv6_test.py b/tests/cts/multidevices/apfv6_test.py
index 6b71c48bd3..4512c2d3fe 100644
--- a/tests/cts/multidevices/apfv6_test.py
+++ b/tests/cts/multidevices/apfv6_test.py
@@ -147,14 +147,8 @@ class ApfV6Test(apf_test_base.ApfTestBase):
         expected_echo_reply,
     )
 
-  def is_running_as_root(self):
-    uid = adb_utils.adb_shell(self.clientDevice, 'id -u')
-    return uid == '0'
-
   @apf_utils.at_least_B()
   def test_igmpv3_general_query_offload(self):
-    if not self.is_running_as_root():
-      return
     # use unicast to replace multicast ether dst to prevent flaky due to DTIM skip
     ether = Ether(src=self.server_mac_address, dst=self.client_mac_address)
     ip = IP(
@@ -167,11 +161,9 @@ class ApfV6Test(apf_test_base.ApfTestBase):
 
     mcast_addrs = ['239.0.0.1', '239.0.0.2', '239.0.0.3']
 
+    self.client.createMulticastSocket(self.client_iface_name)
     for addr in mcast_addrs:
-      adb_utils.adb_shell(
-          self.clientDevice,
-          f'ip addr add {addr}/32 dev {self.client_iface_name} autojoin',
-      )
+      self.client.joinMulticastGroup(addr)
 
     ether = Ether(src=self.client_mac_address, dst='01:00:5e:00:00:16')
     ip = IP(
@@ -196,10 +188,8 @@ class ApfV6Test(apf_test_base.ApfTestBase):
       )
     finally:
       for addr in mcast_addrs:
-        adb_utils.adb_shell(
-            self.clientDevice,
-            f'ip addr del {addr}/32 dev {self.client_iface_name}',
-        )
+        self.client.leaveMulticastGroup(addr)
+      self.client.destroyMulticastSocket()
 
   @apf_utils.at_least_B()
   @apf_utils.apf_ram_at_least(3000)
diff --git a/tests/cts/multidevices/snippet/ConnectivityMultiDevicesSnippet.kt b/tests/cts/multidevices/snippet/ConnectivityMultiDevicesSnippet.kt
index feea1247fd..9f01abaf4f 100644
--- a/tests/cts/multidevices/snippet/ConnectivityMultiDevicesSnippet.kt
+++ b/tests/cts/multidevices/snippet/ConnectivityMultiDevicesSnippet.kt
@@ -47,6 +47,10 @@ import com.android.testutils.TestableNetworkCallback.Event.CapabilitiesChanged
 import com.android.testutils.runAsShell
 import com.google.android.mobly.snippet.Snippet
 import com.google.android.mobly.snippet.rpc.Rpc
+import java.net.InetAddress
+import java.net.InetSocketAddress
+import java.net.MulticastSocket
+import java.net.NetworkInterface
 import org.junit.Rule
 
 class ConnectivityMultiDevicesSnippet : Snippet {
@@ -60,6 +64,7 @@ class ConnectivityMultiDevicesSnippet : Snippet {
     private val cbHelper = NetworkCallbackHelper()
     private val ctsTetheringUtils = CtsTetheringUtils(context)
     private var oldSoftApConfig: SoftApConfiguration? = null
+    private var multicastSocket: MulticastSocket? = null
 
     override fun shutdown() {
         cbHelper.unregisterAll()
@@ -215,4 +220,50 @@ class ConnectivityMultiDevicesSnippet : Snippet {
             }
         }
     }
+
+    @Rpc(description = "Create multicast socket")
+    fun createMulticastSocket(ifname: String) {
+        if (multicastSocket != null) {
+            throw IllegalStateException("multicast socket is not null")
+        }
+
+        multicastSocket = MulticastSocket()
+        multicastSocket?.networkInterface = NetworkInterface.getByName(ifname)
+    }
+
+    @Rpc(description = "Destroy multicast socket")
+    fun destroyMulticastSocket() {
+        if (multicastSocket == null) {
+            throw IllegalStateException("multicast socket is null")
+        }
+
+        multicastSocket?.close()
+        multicastSocket = null
+    }
+
+    @Rpc(description = "Join multicast group")
+    fun joinMulticastGroup(multicastGroup: String) {
+        if (multicastSocket == null) {
+            throw IllegalStateException("multicast socket is null")
+        }
+
+        val groupToJoin = InetAddress.getByName(multicastGroup)
+        multicastSocket?.joinGroup(
+            InetSocketAddress(groupToJoin, 0),
+            multicastSocket?.networkInterface
+        )
+    }
+
+    @Rpc(description = "Leave multicast group")
+    fun leaveMulticastGroup(multicastGroup: String) {
+        if (multicastSocket == null) {
+            throw IllegalStateException("multicast socket is null")
+        }
+
+        val groupToLeave = InetAddress.getByName(multicastGroup)
+        multicastSocket?.leaveGroup(
+            InetSocketAddress(groupToLeave, 0),
+            multicastSocket?.networkInterface
+        )
+    }
 }