97 lines
2.6 KiB
C++
97 lines
2.6 KiB
C++
/* -*- c++ -*- */
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/*
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* Copyright 2019 Thomas Kolb.
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*
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* This is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3, or (at your option)
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* any later version.
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*
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* This software is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this software; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <volk/volk.h>
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#include <gnuradio/io_signature.h>
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#include "async_scrambler_impl.h"
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namespace gr {
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namespace hamnet70 {
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async_scrambler::sptr
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async_scrambler::make(uint8_t start, uint8_t polynom)
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{
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return gnuradio::get_initial_sptr
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(new async_scrambler_impl(start, polynom));
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}
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/*
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* The private constructor
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*/
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async_scrambler_impl::async_scrambler_impl(uint8_t start, uint8_t polynom)
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: gr::block("async_scrambler",
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gr::io_signature::make(0, 0, 0),
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gr::io_signature::make(0, 0, 0)),
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d_start(start),
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d_polynom(polynom)
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{
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d_in_port = pmt::mp("pdu_in");
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d_out_port = pmt::mp("pdu_out");
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message_port_register_in(d_in_port);
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message_port_register_out(d_out_port);
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set_msg_handler(d_in_port, boost::bind(&async_scrambler_impl::scramble, this ,_1) );
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}
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/*
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* Our virtual destructor.
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*/
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async_scrambler_impl::~async_scrambler_impl()
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{
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}
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void async_scrambler_impl::scramble(pmt::pmt_t pdu)
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{
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// extract input pdu
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pmt::pmt_t meta(pmt::car(pdu));
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pmt::pmt_t bytes(pmt::cdr(pdu));
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unsigned int crc;
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size_t pkt_len(0);
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const uint8_t* bytes_in = pmt::u8vector_elements(bytes, pkt_len);
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uint8_t* bytes_out = (uint8_t*)volk_malloc(pkt_len*sizeof(uint8_t),
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volk_get_alignment());
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uint8_t lfsr = d_start;
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for(size_t i = 0; i < pkt_len; i++) {
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bytes_out[i] = bytes_in[i] ^ lfsr;
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if(lfsr & 0x1) {
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lfsr = (lfsr >> 1) ^ d_polynom;
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} else {
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lfsr >>= 1;
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}
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}
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pmt::pmt_t output = pmt::init_u8vector(pkt_len, bytes_out); // this copies the values from bytes_out into the u8vector
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pmt::pmt_t msg_pair = pmt::cons(meta, output);
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message_port_pub(d_out_port, msg_pair);
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volk_free(bytes_out);
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}
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} /* namespace hamnet70 */
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} /* namespace gr */
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