390 lines
9.2 KiB
C
390 lines
9.2 KiB
C
#include <linux/if.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <ctype.h>
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#include <liquid/liquid.h>
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#include <sys/poll.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <poll.h>
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#include <signal.h>
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#include "utils.h"
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#include "options.h"
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#include "layer1/tx.h"
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#include "layer1/rx.h"
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#include "layer2/tundev.h"
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#include "sdr/sdr.h"
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#include "config.h"
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#define RESULT_CHECK(stmt) { \
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result_t res = stmt; \
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if(res != OK) { \
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fprintf(stderr, "Error %d in %s:%d!\n", res, __FILE__, __LINE__); \
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exit(1); \
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} \
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}
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static int m_tunfd = -1;
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static bool m_running = true;
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static double next_tx_switch_time = 0.0;
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static struct {
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size_t preambles_found;
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size_t successful_decodes;
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size_t failed_decodes;
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size_t header_errors;
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} m_stats;
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static void signal_handler(int signal, siginfo_t *info, void *ctx)
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{
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(void)signal;
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(void)info;
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(void)ctx;
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fprintf(stderr, "\nGracefully shutting down on signal %d.\n", signal);
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m_running = false;
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}
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static void block_tx_for(unsigned offset_ms)
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{
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next_tx_switch_time = get_hires_time() + (double)offset_ms * 0.001;
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}
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void print_complex_array(const char *varname, float complex const *array, size_t len)
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{
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fprintf(stderr, "%s=np.array([%f%+fj", varname, crealf(array[0]), cimagf(array[0]));
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for(size_t k = 1; k < len; k++) {
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fprintf(stderr, ", %f%+fj", crealf(array[k]), cimagf(array[k]));
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}
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fprintf(stderr, "])\n");
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}
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void hexdump(const uint8_t *data, size_t len)
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{
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static const char lut[16] = "0123456789ABCDEF";
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static const size_t BYTES_PER_LINE = 16;
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size_t pos = 0;
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while(pos < len) {
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size_t bytes_in_line = len - pos;
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if(bytes_in_line > BYTES_PER_LINE) {
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bytes_in_line = BYTES_PER_LINE;
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}
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for(size_t i = 0; i < BYTES_PER_LINE; i++) {
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if(i >= bytes_in_line) {
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fputs(" ", stderr);
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} else {
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uint8_t byte = data[pos+i];
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fprintf(stderr, "%c%c ", lut[byte >> 4], lut[byte & 0x0F]);
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}
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}
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fputs(" ", stderr);
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for(size_t i = 0; i < bytes_in_line; i++) {
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uint8_t byte = data[pos+i];
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if(isprint(byte)) {
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putc(byte, stderr);
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} else {
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putc('.', stderr);
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}
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}
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putc('\n', stderr);
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pos += bytes_in_line;
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}
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}
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void cb_rx(rx_evt_t evt, uint8_t *packet_data, size_t packet_len)
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{
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int ret;
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switch(evt)
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{
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case RX_EVT_CHECKSUM_ERROR:
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//fprintf(stderr, "Received a message of %zu bytes, but decoding failed.\n", packet_len);
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//fprintf(stderr, "=== FAILED PAYLOAD ===\n");
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//hexdump(packet_data, packet_len);
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//fprintf(stderr, "=======================\n");
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m_stats.failed_decodes++;
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break;
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case RX_EVT_HEADER_ERROR:
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m_stats.header_errors++;
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break;
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case RX_EVT_PACKET_RECEIVED:
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//fprintf(stderr, "A message of %zu bytes was decoded successfully.\n", packet_len);
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//fprintf(stderr, "=== DECODED PAYLOAD (%4zu bytes) ===\n", packet_len);
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//hexdump(packet_data, packet_len < 64 ? packet_len : 64);
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//fprintf(stderr, "====================================\n");
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m_stats.successful_decodes++;
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block_tx_for(TX_SWITCH_BACKOFF_END_OF_PACKET_MS);
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ret = write(m_tunfd, packet_data, packet_len);
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if(ret < 0) {
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perror("write");
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}
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break;
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case RX_EVT_PREAMBLE_FOUND:
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//fprintf(stderr, "Found preamble!\n");
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block_tx_for(TX_SWITCH_BACKOFF_PREAMBLE_MS);
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m_stats.preambles_found++;
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break;
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}
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}
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static int debug_fd;
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static result_t transmit(sdr_ctx_t *sdr, const float complex *samples, size_t len)
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{
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size_t to_transmit_rf = len * SDR_OVERSAMPLING;
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float complex rf_samples[to_transmit_rf];
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RESULT_CHECK(sdr_baseband_to_rf(sdr, samples, len, rf_samples, &to_transmit_rf));
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result_t result = sdr_transmit(sdr, rf_samples, to_transmit_rf, 100000);
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fprintf(stderr, "t");
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return result;
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}
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int main(int argc, char **argv)
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{
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layer1_tx_t tx;
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layer1_rx_t rx;
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sdr_ctx_t sdr;
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int parsed_options = options_parse(argc, argv);
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fprintf(stderr, "%d options parsed.\n", parsed_options);
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if(parsed_options < 0) {
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return EXIT_FAILURE;
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}
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bool on_air = true;
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debug_fd = open("/tmp/dump.cf32", O_CREAT | O_WRONLY | O_TRUNC);
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// ** Initialize **
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char devname[IFNAMSIZ] = "hamnet70";
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m_tunfd = tundev_open(devname);
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if(m_tunfd < 0) {
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return 1;
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}
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RESULT_CHECK(sdr_init(&sdr));
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RESULT_CHECK(layer1_tx_init(&tx));
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RESULT_CHECK(layer1_rx_init(&rx, cb_rx));
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// ** Set up signal handling
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struct sigaction term_action = {0};
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term_action.sa_sigaction = signal_handler;
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if(sigaction(SIGTERM, &term_action, NULL) < 0) {
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perror("sigaction");
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exit(EXIT_FAILURE);
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}
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if(sigaction(SIGINT, &term_action, NULL) < 0) {
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perror("sigaction");
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exit(EXIT_FAILURE);
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}
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// ** Process packets **
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struct pollfd pfd;
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memset(&pfd, 0, sizeof(pfd));
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pfd.fd = m_tunfd;
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pfd.events = POLLIN;
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// start in TX mode to work around SoapyHackRF not setting the correct frequency.
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RESULT_CHECK(sdr_start_tx(&sdr, 1));
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unsigned rx_retries = 0;
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double old = get_hires_time();
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size_t total_samples = 0;
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double next_stats_print_time = old + 0.5;
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while(m_running) {
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double now = get_hires_time();
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if((now > next_tx_switch_time) && (on_air || !layer1_rx_is_busy(&rx))) {
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int ret = poll(&pfd, 1, 0);
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if(ret < 0) {
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perror("poll");
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break;
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} else if(ret > 0) {
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// there is a packet to be read.
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// check free buffer space (50 ms required corresponding to 5000 baseband symbols)
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size_t buffer_free_space_samples = sdr_get_tx_buffer_free_space(&sdr);
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fprintf(stderr, "TX buffer free: %zu\n", buffer_free_space_samples);
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if(buffer_free_space_samples < 400000) { // sample count for 200 ms at 2 MHz
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// try again after a short delay
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fsleep(10e-3);
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continue;
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}
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uint8_t packetbuf[2048];
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ret = read(m_tunfd, packetbuf, sizeof(packetbuf));
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if(ret < 0) {
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perror("read");
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break;
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} else if(ret == 0) {
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// no more data
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break;
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}
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fprintf(stderr, "Transmitting packet with %d bytes.\n", ret);
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RESULT_CHECK(layer1_tx_reset(&tx));
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// ** Modulate packet **
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RESULT_CHECK(layer1_tx_add_packet_to_burst(&tx, packetbuf, ret));
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RESULT_CHECK(layer1_tx_finalize_burst(&tx));
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size_t burst_len = layer1_tx_get_sample_count(&tx);
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const float complex *whole_burst = layer1_tx_get_sample_data(&tx);
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dump_array_cf(whole_burst, burst_len, 1.0f, "/tmp/tx.cpx");
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// ensure that the buffer is full before TX is turned on to avoid transmitting empty buffers
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RESULT_CHECK(transmit(&sdr, whole_burst, burst_len));
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if(!on_air) {
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size_t buffer_used_samples = sdr_get_tx_buffer_used_space(&sdr);
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const size_t min_required_samples = 4*128*1024;
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int ret2 = poll(&pfd, 1, 0);
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if(ret2 < 0) {
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perror("poll");
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break;
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} else if(ret2 != 0 && (buffer_used_samples < min_required_samples)) {
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// enqueue more packets before starting TX
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fprintf(stderr, "Pre-buffering more packets: %zd / %zd samples.\n", buffer_used_samples, min_required_samples);
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continue;
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}
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fprintf(stderr, "RX -> TX\n");
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RESULT_CHECK(sdr_stop_rx(&sdr));
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// transmit packets on the frequency where the last packet was received.
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layer1_tx_set_carrier_frequency_offset(&tx, layer1_rx_get_coarse_carrier_frequency(&rx));
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RESULT_CHECK(sdr_start_tx(&sdr, burst_len * SDR_OVERSAMPLING));
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}
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on_air = true;
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} else if(on_air) { // ret == 0
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fprintf(stderr, "TX -> RX\n");
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RESULT_CHECK(sdr_flush_tx_buffer(&sdr));
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RESULT_CHECK(sdr_stop_tx(&sdr));
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RESULT_CHECK(sdr_start_rx(&sdr));
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on_air = false;
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block_tx_for(TX_SWITCH_BACKOFF_AFTER_RX_ON);
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}
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}
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if(!on_air) {
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// ** Receive signal **
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const size_t CHUNKSIZE_BB = 16384;
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const size_t CHUNKSIZE_RF = (CHUNKSIZE_BB * SDR_OVERSAMPLING);
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float complex rf_samples[CHUNKSIZE_RF];
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float complex bb_samples[CHUNKSIZE_BB];
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size_t n_rf_samples = CHUNKSIZE_RF;
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size_t n_bb_samples = CHUNKSIZE_BB;
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if(sdr_receive(&sdr, rf_samples, &n_rf_samples, 100000) != OK) {
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rx_retries++;
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fprintf(stderr, "sdr_receive() failed %d times.\n", rx_retries);
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if(rx_retries >= 3) {
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break;
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} else {
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continue;
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}
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}
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if(n_rf_samples == 0) {
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fsleep(1e-3);
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continue;
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}
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total_samples += n_rf_samples;
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double new = get_hires_time();
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if(new >= next_stats_print_time) {
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double rate = total_samples / (new - old);
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fprintf(stderr, "\nEstimated rate: %.3f MS/s\n", rate / 1e6);
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fprintf(stderr, "Receiver statistics:\n");
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fprintf(stderr, " Preambles found: %8zd\n", m_stats.preambles_found);
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fprintf(stderr, " Successful decodes: %8zd (%6.2f %%)\n",
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m_stats.successful_decodes, m_stats.successful_decodes * 100.0f / m_stats.preambles_found);
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fprintf(stderr, " Header errors: %8zd (%6.2f %%)\n",
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m_stats.header_errors, m_stats.header_errors * 100.0f / m_stats.preambles_found);
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fprintf(stderr, " Failed decodes: %8zd (%6.2f %%)\n",
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m_stats.failed_decodes, m_stats.failed_decodes * 100.0f / m_stats.preambles_found);
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next_stats_print_time += 0.5;
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total_samples = 0;
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old = new;
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}
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rx_retries = 0;
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fprintf(stderr, "r");
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RESULT_CHECK(sdr_rf_to_baseband(&sdr, rf_samples, n_rf_samples, bb_samples, &n_bb_samples));
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RESULT_CHECK(layer1_rx_process(&rx, bb_samples, n_bb_samples));
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} else {
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rx_retries = 0;
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}
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}
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close(debug_fd);
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// ** Cleanup **
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layer1_tx_shutdown(&tx);
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layer1_rx_shutdown(&rx);
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sdr_destroy(&sdr);
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fprintf(stderr, "Done.\n");
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}
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