mirror of
https://github.com/rtlsdrblog/rtl-sdr-blog.git
synced 2025-01-05 15:57:14 +01:00
9047eef701
With just 'inline', if the compiler decides not to inline them, it isn't required to emit them at all. For some targets with -Os that is causing build failures, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86360. Perhaps we might consider using '__attribute__((always_inline))' for GCC builds, but 'static inline' is a good start. Signed-off-by: Steve Markgraf <steve@steve-m.de>
508 lines
12 KiB
C
508 lines
12 KiB
C
/*
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* rtl-sdr, turns your Realtek RTL2832 based DVB dongle into a SDR receiver
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* Copyright (C) 2012 by Steve Markgraf <steve@steve-m.de>
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* Copyright (C) 2012 by Hoernchen <la@tfc-server.de>
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* Copyright (C) 2012 by Kyle Keen <keenerd@gmail.com>
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* Copyright (C) 2012 by Youssef Touil <youssef@sdrsharp.com>
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* Copyright (C) 2012 by Ian Gilmour <ian@sdrsharp.com>
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*
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* This program 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 2 of the License, or
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* (at your option) any later version.
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*
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* This program 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 program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <errno.h>
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#include <signal.h>
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#include <string.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#ifndef _WIN32
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#include <unistd.h>
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#else
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#include <windows.h>
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#include <fcntl.h>
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#include <io.h>
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#include "getopt/getopt.h"
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#endif
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#include <pthread.h>
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#include <libusb.h>
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#include "rtl-sdr.h"
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#include "convenience/convenience.h"
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#ifdef _WIN32
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#define sleep Sleep
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#if defined(_MSC_VER) && (_MSC_VER < 1800)
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#define round(x) (x > 0.0 ? floor(x + 0.5): ceil(x - 0.5))
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#endif
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#endif
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#define ADSB_RATE 2000000
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#define ADSB_FREQ 1090000000
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#define DEFAULT_ASYNC_BUF_NUMBER 12
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#define DEFAULT_BUF_LENGTH (16 * 16384)
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#define AUTO_GAIN -100
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#define MESSAGEGO 253
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#define OVERWRITE 254
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#define BADSAMPLE 255
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static pthread_t demod_thread;
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static pthread_cond_t ready;
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static pthread_mutex_t ready_m;
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static volatile int do_exit = 0;
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static rtlsdr_dev_t *dev = NULL;
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uint16_t squares[256];
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/* todo, bundle these up in a struct */
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uint8_t *buffer; /* also abused for uint16_t */
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int verbose_output = 0;
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int short_output = 0;
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int quality = 10;
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int allowed_errors = 5;
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FILE *file;
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int adsb_frame[14];
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#define preamble_len 16
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#define long_frame 112
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#define short_frame 56
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/* signals are not threadsafe by default */
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#define safe_cond_signal(n, m) pthread_mutex_lock(m); pthread_cond_signal(n); pthread_mutex_unlock(m)
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#define safe_cond_wait(n, m) pthread_mutex_lock(m); pthread_cond_wait(n, m); pthread_mutex_unlock(m)
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void usage(void)
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{
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fprintf(stderr,
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"rtl_adsb, a simple ADS-B decoder\n\n"
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"Use:\trtl_adsb [-R] [-g gain] [-p ppm] [output file]\n"
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"\t[-d device_index (default: 0)]\n"
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"\t[-V verbove output (default: off)]\n"
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"\t[-S show short frames (default: off)]\n"
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"\t[-Q quality (0: no sanity checks, 0.5: half bit, 1: one bit (default), 2: two bits)]\n"
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"\t[-e allowed_errors (default: 5)]\n"
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"\t[-g tuner_gain (default: automatic)]\n"
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"\t[-p ppm_error (default: 0)]\n"
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"\t[-T enable bias-T on GPIO PIN 0 (works for rtl-sdr.com v3 dongles)]\n"
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"\tfilename (a '-' dumps samples to stdout)\n"
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"\t (omitting the filename also uses stdout)\n\n"
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"Streaming with netcat:\n"
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"\trtl_adsb | netcat -lp 8080\n"
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"\twhile true; do rtl_adsb | nc -lp 8080; done\n"
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"Streaming with socat:\n"
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"\trtl_adsb | socat -u - TCP4:sdrsharp.com:47806\n"
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"\n");
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exit(1);
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}
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#ifdef _WIN32
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BOOL WINAPI
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sighandler(int signum)
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{
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if (CTRL_C_EVENT == signum) {
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fprintf(stderr, "Signal caught, exiting!\n");
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do_exit = 1;
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rtlsdr_cancel_async(dev);
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return TRUE;
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}
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return FALSE;
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}
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#else
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static void sighandler(int signum)
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{
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fprintf(stderr, "Signal caught, exiting!\n");
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do_exit = 1;
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rtlsdr_cancel_async(dev);
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}
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#endif
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void display(int *frame, int len)
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{
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int i, df;
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if (!short_output && len <= short_frame) {
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return;}
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df = (frame[0] >> 3) & 0x1f;
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if (quality == 0 && !(df==11 || df==17 || df==18 || df==19)) {
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return;}
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fprintf(file, "*");
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for (i=0; i<((len+7)/8); i++) {
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fprintf(file, "%02x", frame[i]);}
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fprintf(file, ";\r\n");
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if (!verbose_output) {
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return;}
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fprintf(file, "DF=%i CA=%i\n", df, frame[0] & 0x07);
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fprintf(file, "ICAO Address=%06x\n", frame[1] << 16 | frame[2] << 8 | frame[3]);
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if (len <= short_frame) {
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return;}
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fprintf(file, "PI=0x%06x\n", frame[11] << 16 | frame[12] << 8 | frame[13]);
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fprintf(file, "Type Code=%i S.Type/Ant.=%x\n", (frame[4] >> 3) & 0x1f, frame[4] & 0x07);
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fprintf(file, "--------------\n");
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}
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int abs8(int x)
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/* do not subtract 127 from the raw iq, this handles it */
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{
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if (x >= 127) {
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return x - 127;}
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return 127 - x;
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}
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void squares_precompute(void)
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/* equiv to abs(x-128) ^ 2 */
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{
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int i, j;
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// todo, check if this LUT is actually any faster
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for (i=0; i<256; i++) {
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j = abs8(i);
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squares[i] = (uint16_t)(j*j);
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}
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}
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int magnitute(uint8_t *buf, int len)
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/* takes i/q, changes buf in place (16 bit), returns new len (16 bit) */
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{
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int i;
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uint16_t *m;
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for (i=0; i<len; i+=2) {
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m = (uint16_t*)(&buf[i]);
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*m = squares[buf[i]] + squares[buf[i+1]];
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}
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return len/2;
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}
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static inline uint16_t single_manchester(uint16_t a, uint16_t b, uint16_t c, uint16_t d)
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/* takes 4 consecutive real samples, return 0 or 1, BADSAMPLE on error */
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{
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int bit, bit_p;
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bit_p = a > b;
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bit = c > d;
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if (quality == 0) {
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return bit;}
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if (quality == 5) {
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if ( bit && bit_p && b > c) {
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return BADSAMPLE;}
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if (!bit && !bit_p && b < c) {
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return BADSAMPLE;}
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return bit;
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}
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if (quality == 10) {
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if ( bit && bit_p && c > b) {
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return 1;}
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if ( bit && !bit_p && d < b) {
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return 1;}
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if (!bit && bit_p && d > b) {
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return 0;}
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if (!bit && !bit_p && c < b) {
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return 0;}
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return BADSAMPLE;
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}
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if ( bit && bit_p && c > b && d < a) {
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return 1;}
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if ( bit && !bit_p && c > a && d < b) {
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return 1;}
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if (!bit && bit_p && c < a && d > b) {
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return 0;}
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if (!bit && !bit_p && c < b && d > a) {
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return 0;}
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return BADSAMPLE;
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}
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static inline uint16_t min16(uint16_t a, uint16_t b)
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{
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return a<b ? a : b;
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}
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static inline uint16_t max16(uint16_t a, uint16_t b)
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{
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return a>b ? a : b;
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}
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static inline int preamble(uint16_t *buf, int i)
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/* returns 0/1 for preamble at index i */
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{
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int i2;
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uint16_t low = 0;
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uint16_t high = 65535;
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for (i2=0; i2<preamble_len; i2++) {
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switch (i2) {
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case 0:
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case 2:
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case 7:
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case 9:
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//high = min16(high, buf[i+i2]);
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high = buf[i+i2];
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break;
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default:
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//low = max16(low, buf[i+i2]);
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low = buf[i+i2];
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break;
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}
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if (high <= low) {
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return 0;}
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}
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return 1;
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}
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void manchester(uint16_t *buf, int len)
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/* overwrites magnitude buffer with valid bits (BADSAMPLE on errors) */
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{
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/* a and b hold old values to verify local manchester */
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uint16_t a=0, b=0;
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uint16_t bit;
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int i, i2, start, errors;
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int maximum_i = len - 1; // len-1 since we look at i and i+1
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// todo, allow wrap across buffers
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i = 0;
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while (i < maximum_i) {
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/* find preamble */
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for ( ; i < (len - preamble_len); i++) {
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if (!preamble(buf, i)) {
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continue;}
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a = buf[i];
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b = buf[i+1];
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for (i2=0; i2<preamble_len; i2++) {
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buf[i+i2] = MESSAGEGO;}
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i += preamble_len;
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break;
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}
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i2 = start = i;
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errors = 0;
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/* mark bits until encoding breaks */
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for ( ; i < maximum_i; i+=2, i2++) {
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bit = single_manchester(a, b, buf[i], buf[i+1]);
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a = buf[i];
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b = buf[i+1];
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if (bit == BADSAMPLE) {
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errors += 1;
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if (errors > allowed_errors) {
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buf[i2] = BADSAMPLE;
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break;
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} else {
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bit = a > b;
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/* these don't have to match the bit */
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a = 0;
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b = 65535;
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}
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}
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buf[i] = buf[i+1] = OVERWRITE;
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buf[i2] = bit;
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}
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}
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}
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void messages(uint16_t *buf, int len)
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{
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int i, data_i, index, shift, frame_len;
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// todo, allow wrap across buffers
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for (i=0; i<len; i++) {
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if (buf[i] > 1) {
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continue;}
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frame_len = long_frame;
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data_i = 0;
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for (index=0; index<14; index++) {
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adsb_frame[index] = 0;}
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for(; i<len && buf[i]<=1 && data_i<frame_len; i++, data_i++) {
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if (buf[i]) {
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index = data_i / 8;
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shift = 7 - (data_i % 8);
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adsb_frame[index] |= (uint8_t)(1<<shift);
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}
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if (data_i == 7) {
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if (adsb_frame[0] == 0) {
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break;}
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if (adsb_frame[0] & 0x80) {
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frame_len = long_frame;}
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else {
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frame_len = short_frame;}
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}
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}
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if (data_i < (frame_len-1)) {
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continue;}
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display(adsb_frame, frame_len);
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fflush(file);
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}
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}
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static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
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{
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if (do_exit) {
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return;}
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memcpy(buffer, buf, len);
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safe_cond_signal(&ready, &ready_m);
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}
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static void *demod_thread_fn(void *arg)
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{
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int len;
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while (!do_exit) {
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safe_cond_wait(&ready, &ready_m);
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len = magnitute(buffer, DEFAULT_BUF_LENGTH);
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manchester((uint16_t*)buffer, len);
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messages((uint16_t*)buffer, len);
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}
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rtlsdr_cancel_async(dev);
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return 0;
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}
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int main(int argc, char **argv)
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{
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#ifndef _WIN32
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struct sigaction sigact;
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#endif
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char *filename = NULL;
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int r, opt;
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int gain = AUTO_GAIN; /* tenths of a dB */
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int dev_index = 0;
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int dev_given = 0;
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int ppm_error = 0;
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int enable_biastee = 0;
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pthread_cond_init(&ready, NULL);
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pthread_mutex_init(&ready_m, NULL);
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squares_precompute();
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while ((opt = getopt(argc, argv, "d:g:p:e:Q:VST")) != -1)
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{
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switch (opt) {
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case 'd':
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dev_index = verbose_device_search(optarg);
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dev_given = 1;
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break;
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case 'g':
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gain = (int)(atof(optarg) * 10);
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break;
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case 'p':
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ppm_error = atoi(optarg);
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break;
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case 'V':
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verbose_output = 1;
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break;
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case 'S':
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short_output = 1;
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break;
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case 'e':
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allowed_errors = atoi(optarg);
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break;
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case 'Q':
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quality = (int)(atof(optarg) * 10);
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break;
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case 'T':
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enable_biastee = 1;
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break;
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default:
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usage();
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return 0;
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}
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}
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if (argc <= optind) {
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filename = "-";
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} else {
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filename = argv[optind];
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}
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buffer = malloc(DEFAULT_BUF_LENGTH * sizeof(uint8_t));
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if (!dev_given) {
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dev_index = verbose_device_search("0");
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}
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if (dev_index < 0) {
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exit(1);
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}
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r = rtlsdr_open(&dev, (uint32_t)dev_index);
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if (r < 0) {
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fprintf(stderr, "Failed to open rtlsdr device #%d.\n", dev_index);
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exit(1);
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}
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#ifndef _WIN32
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sigact.sa_handler = sighandler;
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sigemptyset(&sigact.sa_mask);
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sigact.sa_flags = 0;
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sigaction(SIGINT, &sigact, NULL);
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sigaction(SIGTERM, &sigact, NULL);
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sigaction(SIGQUIT, &sigact, NULL);
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sigaction(SIGPIPE, &sigact, NULL);
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#else
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SetConsoleCtrlHandler( (PHANDLER_ROUTINE) sighandler, TRUE );
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#endif
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if (strcmp(filename, "-") == 0) { /* Write samples to stdout */
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file = stdout;
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setvbuf(stdout, NULL, _IONBF, 0);
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#ifdef _WIN32
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_setmode(_fileno(file), _O_BINARY);
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#endif
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} else {
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file = fopen(filename, "wb");
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if (!file) {
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fprintf(stderr, "Failed to open %s\n", filename);
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exit(1);
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}
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}
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/* Set the tuner gain */
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if (gain == AUTO_GAIN) {
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verbose_auto_gain(dev);
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} else {
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gain = nearest_gain(dev, gain);
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verbose_gain_set(dev, gain);
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}
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verbose_ppm_set(dev, ppm_error);
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r = rtlsdr_set_agc_mode(dev, 1);
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/* Set the tuner frequency */
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verbose_set_frequency(dev, ADSB_FREQ);
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/* Set the sample rate */
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verbose_set_sample_rate(dev, ADSB_RATE);
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rtlsdr_set_bias_tee(dev, enable_biastee);
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if (enable_biastee)
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fprintf(stderr, "activated bias-T on GPIO PIN 0\n");
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/* Reset endpoint before we start reading from it (mandatory) */
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verbose_reset_buffer(dev);
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pthread_create(&demod_thread, NULL, demod_thread_fn, (void *)(NULL));
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rtlsdr_read_async(dev, rtlsdr_callback, (void *)(NULL),
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DEFAULT_ASYNC_BUF_NUMBER,
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DEFAULT_BUF_LENGTH);
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if (do_exit) {
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fprintf(stderr, "\nUser cancel, exiting...\n");}
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else {
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fprintf(stderr, "\nLibrary error %d, exiting...\n", r);}
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rtlsdr_cancel_async(dev);
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pthread_cancel(demod_thread);
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pthread_join(demod_thread, NULL);
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pthread_cond_destroy(&ready);
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pthread_mutex_destroy(&ready_m);
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if (file != stdout) {
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fclose(file);}
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rtlsdr_close(dev);
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free(buffer);
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return r >= 0 ? r : -r;
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}
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