code: public static void copyBackRouteHeader(byte[] source, byte[] dest) {
          int thisPointCode = getFromSif_DPC(source, 1);
          int remotePointCode = getFromSif_OPC(source, 1);
          int sls = getFromSif_SLS(source, 1);
          int si = getFromSif_SI(source);
          int ssi = getFromSif_SSI(source);
          writeRoutingLabel(dest, si, ssi, sls, remotePointCode, thisPointCode);
      }
docs: Extract routing information from source[], it expects that source is properly encoded routing label atleast(5bytes long,
  same as dest). It copies data to <b>dest</b> and swamp <i>DPC</i> with <i>OPC</i>.
  
  @param source
  @param dest