using UDP to broadcast on Wifi Direct

Question

i'm new to wifi direct and i want to be able to broadcast a message, because i have a timeline and when i click the Post button i want all the connected devices have that message displayed on their timeline. I am able to send data peer to peer.I have searched about this subject and i found using UDP is a good choice but i don't know how to implement it in wifi direct.

I found this code that uses UDP on wifi to Get the Broadcast Address

InetAddress getBroadcastAddress() throws IOException {
WifiManager wifi = mContext.getSystemService(Context.WIFI_SERVICE);
DhcpInfo dhcp = wifi.getDhcpInfo();
// handle null somehow

int broadcast = (dhcp.ipAddress & dhcp.netmask) | ~dhcp.netmask;
byte[] quads = new byte[4];
for (int k = 0; k < 4; k++)
  quads[k] = (byte) ((broadcast >> k * 8) & 0xFF);
return InetAddress.getByAddress(quads);} 

and this for Sending and Receiving UDP Broadcast Packets

DatagramSocket socket = new DatagramSocket(PORT);
socket.setBroadcast(true);
DatagramPacket packet = new DatagramPacket(data.getBytes(), data.length(),
getBroadcastAddress(), DISCOVERY_PORT);
socket.send(packet);

byte[] buf = new byte[1024];
DatagramPacket packet = new DatagramPacket(buf, buf.length);
socket.receive(packet);

could you please help me and explain to me how it works thanks in advance.

Answer 1

In Android's Wi-Fi P2P there is a concept of "group owner", which is the device that acts as an access point. For the current API the group owner's IP address seems to be set to 192.168.49.1, which I think is hard-coded somewhere. A quick guess on the broadcast address for the group's network will be 192.168.49.255. For all (of a few) devices I have tested so far that turned out to be the case.