CODEWITHSUNDEEP
javamacossocketspermissionsbroadcast
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Reputation: 83

SecurityException sending broadcast from Java on OS X

I'm trying to send a broadcast from java on my mac. This seems like it should work, but I'm getting a SecurityException. I've verified that there isn't a SecurityManager installed, and tried running my class using sudo.

The code:

public static void main(String[] args) throws Exception{
    SocketAddress sockAddr = new InetSocketAddress("192.168.0.255",
            4000);
    ByteBuffer bb = ByteBuffer.allocate(10);
    bb.put(new Byte("1"));
    DatagramChannel channel = DatagramChannel.open();
    channel.send(bb, sockAddr);
}

The exception:

Exception in thread "main" java.net.SocketException: Permission denied
    at sun.nio.ch.DatagramChannelImpl.send0(Native Method)
    at sun.nio.ch.DatagramChannelImpl.sendFromNativeBuffer(DatagramChannelImpl.java:301)
    at sun.nio.ch.DatagramChannelImpl.send(DatagramChannelImpl.java:281)
    at sun.nio.ch.DatagramChannelImpl.send(DatagramChannelImpl.java:250)
    at Test.main(Test.java:15)

Upvotes: 2

Views: 1019

Answers (2)

Anya Shenanigans
Anya Shenanigans

Reputation: 94829

Having done a little googling, you need to tell the socket that the DatagramChannel is using that it's a broadcast Channel using the code:

channel.socket().setBroadcast(true);

I think it's just that you need to set the broadcast socket option on the 'channel', which is the underlying O/S socket. Evidently this will be doable from the channel level once java7 comes out, but currently you need to access the DatagramSocket to set the parameter.

Upvotes: 3

Tom Hawtin - tackline
Tom Hawtin - tackline

Reputation: 147154

That's SocketException not SecurityException (or AccessControlException). Seems that the OS isn't allowing your process to send that datagram.

Upvotes: 0

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