/** * 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; }