#10 HTTPMUSocket.send doesn't multicast to correct address:port

[Tim Malcolm]

Testing with the Intel Device Validator shows that
Cyberlink's notify messages are never received by the
Device Validator.

Problem: HTTPMUSocket.send(..) method does not use a
valid SSDP mutlicast address.

Solution: ensure messages with "null" bind address and "-
1" bind port are sent to multicast address and
port "239.255.255.250:1900"

Tested: partial, on JDK 131

Code: HTTPMUSocket.send method below - sorry, no
diffs, just the complete method is reproduced here:

public boolean send(String msg, String bindAddr, int
bindPort)
{
try {

if (bindAddr == null) bindAddr = SSDP.ADDRESS;
if (bindPort < 0) bindPort = SSDP.PORT;

InetAddress mgroup = InetAddress.getByName(bindAddr);
MulticastSocket msock = new MulticastSocket(bindPort);
if ((bindAddr) != null && (0 < bindPort))
msock.setInterface(InetAddress.getByName(bindAddr));
msock.joinGroup(mgroup);
DatagramPacket dgmPacket = new DatagramPacket
(msg.getBytes(), msg.length(),
mgroup, bindPort);
msock.send(dgmPacket);
msock.leaveGroup(mgroup);

}
catch (Exception e) {
Debug.warning(e);
return false;
}
return true;
}

[Tim Malcolm]

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I didn't test the code above properly.

The line
if ((bindAddr) != null && (0 < bindPort))
is redundant and can be removed.

The line
msock.setInterface(InetAddress.getByName(bindAddr));
causes an exception and must be removed.

[Tim Malcolm]

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I didn't test the code above properly.

The line
if ((bindAddr) != null && (0 < bindPort))
is redundant and can be removed.

The line
msock.setInterface(InetAddress.getByName(bindAddr));
causes an exception and must be removed.

[Satoshi Konno]

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Hi Tim

I checked your codes with the Intel Device Validator . Thanks
for your effrot :-)

I changed the HTTPMUSocket::send() as the following and
release the package as v 1.2.
Please check it :-)

public boolean send(String msg, String bindAddr, int bindPort)
{
try {
MulticastSocket msock;
if ((bindAddr) != null && (0 < bindPort)) {
msock = new MulticastSocket(null);
msock.bind(new InetSocketAddress(bindAddr, bindPort));
}
else
msock = new MulticastSocket();
DatagramPacket dgmPacket = new DatagramPacket
(msg.getBytes(), msg.length(), ssdpMultiGroup);
msock.send(dgmPacket);
msock.close();
}
catch (Exception e) {
Debug.warning(e);
return false;
}
return true;
}

The bindAddr and bindPort are local interface address and
port, and the multicast doesn't have to
join the multicast network for sending. Please check the
following document.

Java2 Platform SE Document (MulticastSocket)
http://java.sun.com/j2se/1.4.1/docs/api/java/net/MulticastSo
cket.html
When one sends a message to a multicast group, all
subscribing recipients to that host and port receive the
message (within the time-to-live range of the packet, see
below). The socket needn't be a member of the multicast
group to send messages to it.

[Rembo]

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the joingroup and leavegroup is not necessary for sending to
a multicast group. Moreover I have noticed that this can
cause trouble when running under linux and using a firewall.

[Rembo]

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user_id=1262118

Ummm, ok. Next time I'll first read all the comments before
posting.