/**
* Determines whether a specific array of <tt>byte</tt>s appears to contain a DTLS record.
*
* @param buf the array of <tt>byte</tt>s to be analyzed
* @param off the offset within <tt>buf</tt> at which the analysis is to start
* @param len the number of bytes within <tt>buf</tt> starting at <tt>off</tt> to be analyzed
* @return <tt>true</tt> if the specified <tt>buf</tt> appears to contain a DTLS record
*/
public static boolean isDtlsRecord(byte[] buf, int off, int len) {
boolean b = false;
if (len >= DTLS_RECORD_HEADER_LENGTH) {
short type = TlsUtils.readUint8(buf, off);
switch (type) {
case ContentType.alert:
case ContentType.application_data:
case ContentType.change_cipher_spec:
case ContentType.handshake:
int major = buf[off + 1] & 0xff;
int minor = buf[off + 2] & 0xff;
ProtocolVersion version = null;
if ((major == ProtocolVersion.DTLSv10.getMajorVersion())
&& (minor == ProtocolVersion.DTLSv10.getMinorVersion())) {
version = ProtocolVersion.DTLSv10;
}
if ((version == null)
&& (major == ProtocolVersion.DTLSv12.getMajorVersion())
&& (minor == ProtocolVersion.DTLSv12.getMinorVersion())) {
version = ProtocolVersion.DTLSv12;
}
if (version != null) {
int length = TlsUtils.readUint16(buf, off + 11);
if (DTLS_RECORD_HEADER_LENGTH + length <= len) b = true;
}
break;
default:
// Unless a new ContentType has been defined by the Bouncy
// Castle Crypto APIs, the specified buf does not represent a
// DTLS record.
break;
}
}
return b;
}
