Anton Ottosson
e620d48c81
The Frame Equalizer used to propagate metadata as a dictionary stored in a single tag. Now it instead propagates each entry as a separate tag, which is more in line with how standard GNU Radio blocks do it (see for example PDU to Tagged Stream block). This is also how the Extract CSI block does it. This modification also removes a lot of unnecessary variables and type conversions (from and to pmt types) in the Decode MAC block.
256 lines
7.8 KiB
C++
256 lines
7.8 KiB
C++
/*
|
|
* Copyright (C) 2013, 2016 Bastian Bloessl <bloessl@ccs-labs.org>
|
|
*
|
|
* This program is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
#include <ieee802_11/decode_mac.h>
|
|
|
|
#include "utils.h"
|
|
#include "viterbi_decoder/viterbi_decoder.h"
|
|
|
|
#include <gnuradio/io_signature.h>
|
|
#include <boost/crc.hpp>
|
|
|
|
using namespace gr::ieee802_11;
|
|
|
|
#define LINKTYPE_IEEE802_11 105 /* http://www.tcpdump.org/linktypes.html */
|
|
|
|
class decode_mac_impl : public decode_mac
|
|
{
|
|
|
|
public:
|
|
decode_mac_impl(bool log, bool debug)
|
|
: block("decode_mac",
|
|
gr::io_signature::make(1, 1, 48),
|
|
gr::io_signature::make(0, 0, 0)),
|
|
d_log(log),
|
|
d_debug(debug),
|
|
d_ofdm(BPSK_1_2),
|
|
d_frame(d_ofdm, 0),
|
|
d_frame_complete(true)
|
|
{
|
|
message_port_register_out(pmt::mp("out"));
|
|
}
|
|
|
|
int general_work(int noutput_items,
|
|
gr_vector_int& ninput_items,
|
|
gr_vector_const_void_star& input_items,
|
|
gr_vector_void_star& output_items)
|
|
{
|
|
|
|
const uint8_t* in = (const uint8_t*)input_items[0];
|
|
|
|
int i = 0;
|
|
|
|
std::vector<gr::tag_t> tags;
|
|
const uint64_t nread = this->nitems_read(0);
|
|
|
|
dout << "Decode MAC: input " << ninput_items[0] << std::endl;
|
|
|
|
while (i < ninput_items[0]) {
|
|
|
|
get_tags_in_range(tags, 0, nread + i, nread + i + 1);
|
|
|
|
if (tags.size()) {
|
|
if (d_frame_complete == false) {
|
|
dout << "Warning: starting to receive new frame before old frame was "
|
|
"complete"
|
|
<< std::endl;
|
|
dout << "Already copied " << copied << " out of " << d_frame.n_sym
|
|
<< " symbols of last frame" << std::endl;
|
|
}
|
|
d_frame_complete = false;
|
|
|
|
// Enter tags into metadata dictionary
|
|
d_meta = pmt::make_dict();
|
|
for (auto tag : tags)
|
|
d_meta = pmt::dict_add(d_meta, tag.key, tag.value);
|
|
|
|
int len_data = pmt::to_uint64(pmt::dict_ref(
|
|
d_meta, pmt::mp("frame_bytes"), pmt::from_uint64(MAX_PSDU_SIZE + 1)));
|
|
int encoding = pmt::to_uint64(
|
|
pmt::dict_ref(d_meta, pmt::mp("encoding"), pmt::from_uint64(0)));
|
|
|
|
ofdm_param ofdm = ofdm_param((Encoding)encoding);
|
|
frame_param frame = frame_param(ofdm, len_data);
|
|
|
|
// check for maximum frame size
|
|
if (frame.n_sym <= MAX_SYM && frame.psdu_size <= MAX_PSDU_SIZE) {
|
|
d_ofdm = ofdm;
|
|
d_frame = frame;
|
|
copied = 0;
|
|
dout << "Decode MAC: frame start -- len " << len_data << " symbols "
|
|
<< frame.n_sym << " encoding " << encoding << std::endl;
|
|
} else {
|
|
dout << "Dropping frame which is too large (symbols or bits)"
|
|
<< std::endl;
|
|
}
|
|
}
|
|
|
|
if (copied < d_frame.n_sym) {
|
|
dout << "copy one symbol, copied " << copied << " out of "
|
|
<< d_frame.n_sym << std::endl;
|
|
std::memcpy(d_rx_symbols + (copied * 48), in, 48);
|
|
copied++;
|
|
|
|
if (copied == d_frame.n_sym) {
|
|
dout << "received complete frame - decoding" << std::endl;
|
|
decode();
|
|
in += 48;
|
|
i++;
|
|
d_frame_complete = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
in += 48;
|
|
i++;
|
|
}
|
|
|
|
consume(0, i);
|
|
|
|
return 0;
|
|
}
|
|
|
|
void decode()
|
|
{
|
|
|
|
for (int i = 0; i < d_frame.n_sym * 48; i++) {
|
|
for (int k = 0; k < d_ofdm.n_bpsc; k++) {
|
|
d_rx_bits[i * d_ofdm.n_bpsc + k] = !!(d_rx_symbols[i] & (1 << k));
|
|
}
|
|
}
|
|
|
|
deinterleave();
|
|
uint8_t* decoded = d_decoder.decode(&d_ofdm, &d_frame, d_deinterleaved_bits);
|
|
descramble(decoded);
|
|
print_output();
|
|
|
|
// skip service field
|
|
boost::crc_32_type result;
|
|
result.process_bytes(out_bytes + 2, d_frame.psdu_size);
|
|
if (result.checksum() != 558161692) {
|
|
dout << "checksum wrong -- dropping" << std::endl;
|
|
return;
|
|
}
|
|
|
|
mylog(boost::format("encoding: %1% - length: %2% - symbols: %3%") %
|
|
d_ofdm.encoding % d_frame.psdu_size % d_frame.n_sym);
|
|
|
|
// create PDU
|
|
pmt::pmt_t blob = pmt::make_blob(out_bytes + 2, d_frame.psdu_size - 4);
|
|
d_meta = pmt::dict_add(
|
|
d_meta, pmt::mp("dlt"), pmt::from_long(LINKTYPE_IEEE802_11));
|
|
|
|
message_port_pub(pmt::mp("out"), pmt::cons(d_meta, blob));
|
|
}
|
|
|
|
void deinterleave()
|
|
{
|
|
|
|
int n_cbps = d_ofdm.n_cbps;
|
|
int first[n_cbps];
|
|
int second[n_cbps];
|
|
int s = std::max(d_ofdm.n_bpsc / 2, 1);
|
|
|
|
for (int j = 0; j < n_cbps; j++) {
|
|
first[j] = s * (j / s) + ((j + int(floor(16.0 * j / n_cbps))) % s);
|
|
}
|
|
|
|
for (int i = 0; i < n_cbps; i++) {
|
|
second[i] = 16 * i - (n_cbps - 1) * int(floor(16.0 * i / n_cbps));
|
|
}
|
|
|
|
int count = 0;
|
|
for (int i = 0; i < d_frame.n_sym; i++) {
|
|
for (int k = 0; k < n_cbps; k++) {
|
|
d_deinterleaved_bits[i * n_cbps + second[first[k]]] =
|
|
d_rx_bits[i * n_cbps + k];
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
void descramble(uint8_t* decoded_bits)
|
|
{
|
|
|
|
int state = 0;
|
|
std::memset(out_bytes, 0, d_frame.psdu_size + 2);
|
|
|
|
for (int i = 0; i < 7; i++) {
|
|
if (decoded_bits[i]) {
|
|
state |= 1 << (6 - i);
|
|
}
|
|
}
|
|
out_bytes[0] = state;
|
|
|
|
int feedback;
|
|
int bit;
|
|
|
|
for (int i = 7; i < d_frame.psdu_size * 8 + 16; i++) {
|
|
feedback = ((!!(state & 64))) ^ (!!(state & 8));
|
|
bit = feedback ^ (decoded_bits[i] & 0x1);
|
|
out_bytes[i / 8] |= bit << (i % 8);
|
|
state = ((state << 1) & 0x7e) | feedback;
|
|
}
|
|
}
|
|
|
|
void print_output()
|
|
{
|
|
|
|
dout << std::endl;
|
|
dout << "psdu size" << d_frame.psdu_size << std::endl;
|
|
for (int i = 2; i < d_frame.psdu_size + 2; i++) {
|
|
dout << std::setfill('0') << std::setw(2) << std::hex
|
|
<< ((unsigned int)out_bytes[i] & 0xFF) << std::dec << " ";
|
|
if (i % 16 == 15) {
|
|
dout << std::endl;
|
|
}
|
|
}
|
|
dout << std::endl;
|
|
for (int i = 2; i < d_frame.psdu_size + 2; i++) {
|
|
if ((out_bytes[i] > 31) && (out_bytes[i] < 127)) {
|
|
dout << ((char)out_bytes[i]);
|
|
} else {
|
|
dout << ".";
|
|
}
|
|
}
|
|
dout << std::endl;
|
|
}
|
|
|
|
private:
|
|
bool d_debug;
|
|
bool d_log;
|
|
|
|
pmt::pmt_t d_meta;
|
|
|
|
frame_param d_frame;
|
|
ofdm_param d_ofdm;
|
|
|
|
viterbi_decoder d_decoder;
|
|
|
|
uint8_t d_rx_symbols[48 * MAX_SYM];
|
|
uint8_t d_rx_bits[MAX_ENCODED_BITS];
|
|
uint8_t d_deinterleaved_bits[MAX_ENCODED_BITS];
|
|
uint8_t out_bytes[MAX_PSDU_SIZE + 2]; // 2 for signal field
|
|
|
|
int copied;
|
|
bool d_frame_complete;
|
|
};
|
|
|
|
decode_mac::sptr decode_mac::make(bool log, bool debug)
|
|
{
|
|
return gnuradio::get_initial_sptr(new decode_mac_impl(log, debug));
|
|
}
|