TFTP_ERROR
if (tr->opcode == ntohs(TFTP_ERROR))
tp.opcode = htons(TFTP_ERROR);
if (tr->opcode == ntohs (TFTP_ERROR))
tp.opcode = htons (TFTP_ERROR);
tp.opcode = abort ? htons (TFTP_ERROR) : htons (TFTP_ACK);