AccountingReq message authenticator

28 Sep 2005

      Hi.

Is there anyway to generate a message authenticator for an accounting
request packet.  At the moment I am using JRadius, I need to send an
accounting request message to another radius server.  However after I
add the message authenticator and send to to another server, the other
server complains about "Invalid message authenticator"  (Shared secret
is incorrect).

Here is some code :

//Proxy request to the wap gateway

DatagramSocket socket = new DatagramSocket();

socket.setSoTimeout(5000);

                                                            //Generate
authenticator

MessageDigest md5 = MessageDigest.getInstance("MD5");

                                                            md5.reset();

md5.update((byte)req.getCode());

md5.update((byte)req.getIdentifier());

                                            int length =
req.getBytes().length;

                                            byte [] authenticator =
req.getAuthenticator();

                                            byte [] attributeBytes =
req.getAttributeBytes(req.getAttributes(),0);

                                            for (int z=0; z
<authenticator.length ; z++ )

RadiusLog.debug("Autenticator["+z+"] Before = " + authenticator[z]);

RadiusLog.debug("Autenticator Length: " + authenticator.length);

                                            RadiusLog.debug("Attributes
Length: " + attributeBytes.length);

                                            RadiusLog.debug("Paket
Length: " + length);

                                            String sharedSecret =
"testing123";

                                            md5.update((byte)(length >>
8));

                                            md5.update((byte)(length &
0xff));

                                            md5.update(authenticator, 0,
authenticator.length);

                                            md5.update(attributeBytes,
0, attributeBytes.length);

md5.update(sharedSecret.getBytes());         

req.overwriteAttribute(AttributeFactory.newAttribute(AttributeDictionary
.MESSAGE_AUTHENTICATOR, authenticator));

System.arraycopy(md5.digest(), 0, authenticator, 0, 16);

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AccountingReq message authenticator

Ashwin Gobind