From 6fc44359ebdc6bf10eec98cc5828a1d2fa75534d Mon Sep 17 00:00:00 2001
From: Remi NGUYEN VAN <reminv@google.com>
Date: Wed, 13 Oct 2021 14:41:58 +0000
Subject: [PATCH] Add IFF_MULTICAST to test interfaces

This allows using test interfaces for multicast scenarios, such as
testing mDNS behavior.

Test: atest CtsNetTestCases
Change-Id: Ib5d8a997176f910d499021fdcd12c361aff1233d
---
 service/jni/com_android_server_TestNetworkService.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/service/jni/com_android_server_TestNetworkService.cpp b/service/jni/com_android_server_TestNetworkService.cpp
index e7a40e5ea6..1a0de32ae9 100644
--- a/service/jni/com_android_server_TestNetworkService.cpp
+++ b/service/jni/com_android_server_TestNetworkService.cpp
@@ -66,6 +66,8 @@ static int createTunTapInterface(JNIEnv* env, bool isTun, const char* iface) {
     // Activate interface using an unconnected datagram socket.
     base::unique_fd inet6CtrlSock(socket(AF_INET6, SOCK_DGRAM, 0));
     ifr.ifr_flags = IFF_UP;
+    // Mark TAP interfaces as supporting multicast
+    if (!isTun) ifr.ifr_flags |= IFF_MULTICAST;
 
     if (ioctl(inet6CtrlSock.get(), SIOCSIFFLAGS, &ifr)) {
         throwException(env, errno, "activating", ifr.ifr_name);