text: /*
   * rtl-sdr, turns your Realtek RTL2832 based DVB dongle into a SDR receiver
   * Copyright (C) 2012 by Steve Markgraf <steve@steve-m.de>
   * Copyright (C) 2012-2013 by Hoernchen <la@tfc-server.de>
   *
   * 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 2 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 <errno.h>
  #include <signal.h>
  #include <string.h>
  #include <stdio.h>
  #include <stdlib.h>
  
  #ifndef _WIN32
  #include <unistd.h>
  #include <arpa/inet.h>
  #include <sys/socket.h>
  #include <sys/types.h>
  #include <sys/socket.h>
  #include <sys/time.h>
  #include <netinet/in.h>
  #include <fcntl.h>
  #else
  #include <winsock2.h>
  #include "getopt/getopt.h"
  #endif
  
  #include <pthread.h>
  
  #include "rtl-sdr.h"
  #include "convenience/convenience.h"
  
  #ifdef _WIN32
  #pragma comment(lib, "ws2_32.lib")
  
  typedef int socklen_t;
  
  #else
  #define closesocket close
  #define SOCKADDR struct sockaddr
  #define SOCKET int
  #define SOCKET_ERROR -1
  #endif
  
  static SOCKET s;
  
  static pthread_t tcp_worker_thread;
  static pthread_t command_thread;
  static pthread_cond_t exit_cond;
  static pthread_mutex_t exit_cond_lock;
  
  static pthread_mutex_t ll_mutex;
  static pthread_cond_t cond;
  
  struct llist {
  	char *data;
  	size_t len;
  	struct llist *next;
  };
  
  typedef struct { /* structure size must be multiple of 2 bytes */
  	char magic[4];
  	uint32_t tuner_type;
  	uint32_t tuner_gain_count;
  } dongle_info_t;
  
  static rtlsdr_dev_t *dev = NULL;
  
  int global_numq = 0;
  static struct llist *ll_buffers = 0;
  int llbuf_num=500;
  int sampling = 0;
  static volatile int do_exit = 0;
  
  void usage(void)
  {
  	printf("rtl_tcp, an I/Q spectrum server for RTL2832 based DVB-T receivers\nModified by Jakub/SP5TOF on 07.02.2017 for direct sampling support\n\n"
  		"Usage:\t[-a listen address]\n"
  		"\t[-p listen port (default: 1234)]\n"
  		"\t[-f frequency to tune to [Hz]]\n"
  		"\t[-g gain (default: 0 for auto)]\n"
  		"\t[-s samplerate in Hz (default: 2048000 Hz)]\n"
  		"\t[-b number of buffers (default: 32, set by library)]\n"
  		"\t[-n max number of linked list buffers to keep (default: 500)]\n"
  		"\t[-d device index (default: 0)]\n"
  		"\t[-P ppm_error (default: 0)]\n"
  		"\t[-i direct sampling(1: I-ADC input enabled), 2: Q-ADC input enabled)]\n");
  	exit(1);
  }
  
  #ifdef _WIN32
  int gettimeofday(struct timeval *tv, void* ignored)
  {
  	FILETIME ft;
  	unsigned __int64 tmp = 0;
  	if (NULL != tv) {
  		GetSystemTimeAsFileTime(&ft);
  		tmp |= ft.dwHighDateTime;
  		tmp <<= 32;
  		tmp |= ft.dwLowDateTime;
  		tmp /= 10;
  #ifdef _MSC_VER
  		tmp -= 11644473600000000Ui64;
  #else
  		tmp -= 11644473600000000ULL;
  #endif
  		tv->tv_sec = (long)(tmp / 1000000UL);
  		tv->tv_usec = (long)(tmp % 1000000UL);
  	}
  	return 0;
  }
  
  BOOL WINAPI
  sighandler(int signum)
  {
  	if (CTRL_C_EVENT == signum) {
  		fprintf(stderr, "Signal caught, exiting!\n");
  		do_exit = 1;
  		rtlsdr_cancel_async(dev);
  		return TRUE;
  	}
  	return FALSE;
  }
  #else
  static void sighandler(int signum)
  {
  	fprintf(stderr, "Signal caught, exiting!\n");
  	rtlsdr_cancel_async(dev);
  	do_exit = 1;
  }
  #endif
  
  void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
  {
  	if(!do_exit) {
  		struct llist *rpt = (struct llist*)malloc(sizeof(struct llist));
  		rpt->data = (char*)malloc(len);
  		memcpy(rpt->data, buf, len);
  		rpt->len = len;
  		rpt->next = NULL;
  
  		pthread_mutex_lock(&ll_mutex);
  
  		if (ll_buffers == NULL) {
  			ll_buffers = rpt;
  		} else {
  			struct llist *cur = ll_buffers;
  			int num_queued = 0;
  
  			while (cur->next != NULL) {
  				cur = cur->next;
  				num_queued++;
  			}
  
  			if(llbuf_num && llbuf_num == num_queued-2){
  				struct llist *curelem;
  
  				free(ll_buffers->data);
  				curelem = ll_buffers->next;
  				free(ll_buffers);
  				ll_buffers = curelem;
  			}
  
  			cur->next = rpt;
  
  			if (num_queued > global_numq)
  				printf("ll+, now %d\n", num_queued);
  			else if (num_queued < global_numq)
  				printf("ll-, now %d\n", num_queued);
  
  			global_numq = num_queued;
  		}
  		pthread_cond_signal(&cond);
  		pthread_mutex_unlock(&ll_mutex);
  	}
  }
  
  static void *tcp_worker(void *arg)
  {
  	struct llist *curelem,*prev;
  	int bytesleft,bytessent, index;
  	struct timeval tv= {1,0};
  	struct timespec ts;
  	struct timeval tp;
  	fd_set writefds;
  	int r = 0;
  
  	while(1) {
  		if(do_exit)
  			pthread_exit(0);
  
  		pthread_mutex_lock(&ll_mutex);
  		gettimeofday(&tp, NULL);
  		ts.tv_sec  = tp.tv_sec+5;
  		ts.tv_nsec = tp.tv_usec * 1000;
  		r = pthread_cond_timedwait(&cond, &ll_mutex, &ts);
  		if(r == ETIMEDOUT) {
  			pthread_mutex_unlock(&ll_mutex);
  			printf("worker cond timeout\n");
  			sighandler(0);
  			pthread_exit(NULL);
  		}
  
  		curelem = ll_buffers;
  		ll_buffers = 0;
  		pthread_mutex_unlock(&ll_mutex);
  
  		while(curelem != 0) {
  			bytesleft = curelem->len;
  			index = 0;
  			bytessent = 0;
  			while(bytesleft > 0) {
  				FD_ZERO(&writefds);
  				FD_SET(s, &writefds);
  				tv.tv_sec = 1;
  				tv.tv_usec = 0;
  				r = select(s+1, NULL, &writefds, NULL, &tv);
  				if(r) {
  					bytessent = send(s,  &curelem->data[index], bytesleft, 0);
  					bytesleft -= bytessent;
  					index += bytessent;
  				}
  				if(bytessent == SOCKET_ERROR || do_exit) {
  						printf("worker socket bye\n");
  						sighandler(0);
  						pthread_exit(NULL);
  				}
  			}
  			prev = curelem;
  			curelem = curelem->next;
  			free(prev->data);
  			free(prev);
  		}
  	}
  }
  
  static int set_gain_by_index(rtlsdr_dev_t *_dev, unsigned int index)
  {
  	int res = 0;
  	int* gains;
  	int count = rtlsdr_get_tuner_gains(_dev, NULL);
  
  	if (count > 0 && (unsigned int)count > index) {
  		gains = malloc(sizeof(int) * count);
  		count = rtlsdr_get_tuner_gains(_dev, gains);
  
  		res = rtlsdr_set_tuner_gain(_dev, gains[index]);
  
  		free(gains);
  	}
  
  	return res;
  }
  
  #ifdef _WIN32
  #define __attribute__(x)
  #pragma pack(push, 1)
  #endif
  struct command{
  	unsigned char cmd;
  	unsigned int param;
  }__attribute__((packed));
  #ifdef _WIN32
  #pragma pack(pop)
  #endif
  static void *command_worker(void *arg)
  {
  	int left, received = 0;
  	fd_set readfds;
  	struct command cmd={0, 0};
  	struct timeval tv= {1, 0};
  	int r = 0;
  	uint32_t tmp;
  
  	while(1) {
  		left=sizeof(cmd);
  		while(left >0) {
  			FD_ZERO(&readfds);
  			FD_SET(s, &readfds);
  			tv.tv_sec = 1;
  			tv.tv_usec = 0;
  			r = select(s+1, &readfds, NULL, NULL, &tv);
  			if(r) {
  				received = recv(s, (char*)&cmd+(sizeof(cmd)-left), left, 0);
  				left -= received;
  			}
  			if(received == SOCKET_ERROR || do_exit) {
  				printf("comm recv bye\n");
  				sighandler(0);
  				pthread_exit(NULL);
  			}
  		}
  		switch(cmd.cmd) {
  		case 0x01:
  			printf("set freq %d\n", ntohl(cmd.param));
  			rtlsdr_set_center_freq(dev,ntohl(cmd.param));
  			break;
  		case 0x02:
  			printf("set sample rate %d\n", ntohl(cmd.param));
  			rtlsdr_set_sample_rate(dev, ntohl(cmd.param));
  			if (sampling>0)
  			{
  			rtlsdr_set_direct_sampling(dev, sampling);
  			rtlsdr_set_agc_mode(dev, 0);
  			rtlsdr_set_tuner_gain_mode(dev, 1);
  			}
  			break;
  		case 0x03:
  			printf("set gain mode %d\n", ntohl(cmd.param));
  			rtlsdr_set_tuner_gain_mode(dev, ntohl(cmd.param));
  			break;
  		case 0x04:
  			printf("set gain %d\n", ntohl(cmd.param));
  			rtlsdr_set_tuner_gain(dev, ntohl(cmd.param));
  			break;
  		case 0x05:
  			printf("set freq correction %d\n", ntohl(cmd.param));
  			rtlsdr_set_freq_correction(dev, ntohl(cmd.param));
  			break;
  		case 0x06:
  			tmp = ntohl(cmd.param);
  			printf("set if stage %d gain %d\n", tmp >> 16, (short)(tmp & 0xffff));
  			rtlsdr_set_tuner_if_gain(dev, tmp >> 16, (short)(tmp & 0xffff));
  			break;
  		case 0x07:
  			printf("set test mode %d\n", ntohl(cmd.param));
  			rtlsdr_set_testmode(dev, ntohl(cmd.param));
  			break;
  		case 0x08:
  			printf("set agc mode %d\n", ntohl(cmd.param));
  			rtlsdr_set_agc_mode(dev, ntohl(cmd.param));
  			break;
  		case 0x09:
  			printf("set direct sampling %d\n", ntohl(cmd.param));
  			rtlsdr_set_direct_sampling(dev, ntohl(cmd.param));
  			break;
  		case 0x0a:
  			printf("set offset tuning %d\n", ntohl(cmd.param));
  			rtlsdr_set_offset_tuning(dev, ntohl(cmd.param));
  			break;
  		case 0x0b:
  			printf("set rtl xtal %d\n", ntohl(cmd.param));
  			rtlsdr_set_xtal_freq(dev, ntohl(cmd.param), 0);
  			break;
  		case 0x0c:
  			printf("set tuner xtal %d\n", ntohl(cmd.param));
  			rtlsdr_set_xtal_freq(dev, 0, ntohl(cmd.param));
  			break;
  		case 0x0d:
  			printf("set tuner gain by index %d\n", ntohl(cmd.param));
  			set_gain_by_index(dev, ntohl(cmd.param));
  			break;
  		default:
  			break;
  		}
  		cmd.cmd = 0xff;
  	}
  }
  
  int main(int argc, char **argv)
  {
  	int r, opt, i;
  	char* addr = "127.0.0.1";
  	int port = 1234;
  	uint32_t frequency = 100000000, samp_rate = 2048000;
  	struct sockaddr_in local, remote;
  	uint32_t buf_num = 0;
  	int dev_index = 0;
  	int dev_given = 0;
  	int gain = 0;
  	int ppm_error = 0;
  	struct llist *curelem,*prev;
  	pthread_attr_t attr;
  	void *status;
  	struct timeval tv = {1,0};
  	struct linger ling = {1,0};
  	SOCKET listensocket;
  	socklen_t rlen;
  	fd_set readfds;
  	u_long blockmode = 1;
  	dongle_info_t dongle_info;
  #ifdef _WIN32
  	WSADATA wsd;
  	i = WSAStartup(MAKEWORD(2,2), &wsd);
  #else
  	struct sigaction sigact, sigign;
  #endif
  
  	while ((opt = getopt(argc, argv, "a:p:f:g:s:b:n:d:P:i:")) != -1) {
  		switch (opt) {
  		case 'd':
  			dev_index = verbose_device_search(optarg);
  			dev_given = 1;
  			break;
  		case 'f':
  			frequency = (uint32_t)atofs(optarg);
  			break;
  		case 'g':
  			gain = (int)(atof(optarg) * 10); /* tenths of a dB */
  			break;
  		case 's':
  			samp_rate = (uint32_t)atofs(optarg);
  			break;
  		case 'a':
  			addr = optarg;
  			break;
  		case 'p':
  			port = atoi(optarg);
  			break;
  		case 'b':
  			buf_num = atoi(optarg);
  			break;
  		case 'n':
  			llbuf_num = atoi(optarg);
  			break;
  		case 'P':
  			ppm_error = atoi(optarg);
  			break;
  
  		case 'i':
  			sampling = atoi(optarg);
  			break;
  
  		default:
  			usage();
  			break;
  		}
  	}
  
  	if (argc < optind)
  		usage();
  
  	if (!dev_given) {
  		dev_index = verbose_device_search("0");
  	}
  
  	if (dev_index < 0) {
  	    exit(1);
  	}
  
  	rtlsdr_open(&dev, (uint32_t)dev_index);
  	if (NULL == dev) {
  	fprintf(stderr, "Failed to open rtlsdr device #%d.\n", dev_index);
  		exit(1);
  	}
  
  #ifndef _WIN32
  	sigact.sa_handler = sighandler;
  	sigemptyset(&sigact.sa_mask);
  	sigact.sa_flags = 0;
  	sigign.sa_handler = SIG_IGN;
  	sigaction(SIGINT, &sigact, NULL);
  	sigaction(SIGTERM, &sigact, NULL);
  	sigaction(SIGQUIT, &sigact, NULL);
  	sigaction(SIGPIPE, &sigign, NULL);
  #else
  	SetConsoleCtrlHandler( (PHANDLER_ROUTINE) sighandler, TRUE );
  #endif
  
  	/* Set the tuner error */
  	verbose_ppm_set(dev, ppm_error);
  
  	/* Set the sample rate */
  	r = rtlsdr_set_sample_rate(dev, samp_rate);
  	if (r < 0)
  		fprintf(stderr, "WARNING: Failed to set sample rate.\n");
  
  	/* Set the frequency */
  	r = rtlsdr_set_center_freq(dev, frequency);
  	if (r < 0)
  		fprintf(stderr, "WARNING: Failed to set center freq.\n");
  	else
  		fprintf(stderr, "Tuned to %i Hz.\n", frequency);
  
  	if (0 == gain) {
  		 /* Enable automatic gain */
  		r = rtlsdr_set_tuner_gain_mode(dev, 0);
  		if (r < 0)
  			fprintf(stderr, "WARNING: Failed to enable automatic gain.\n");
  	} else {
  		/* Enable manual gain */
  		r = rtlsdr_set_tuner_gain_mode(dev, 1);
  		if (r < 0)
  			fprintf(stderr, "WARNING: Failed to enable manual gain.\n");
  
  		/* Set the tuner gain */
  		r = rtlsdr_set_tuner_gain(dev, gain);
  		if (r < 0)
  			fprintf(stderr, "WARNING: Failed to set tuner gain.\n");
  		else
  			fprintf(stderr, "Tuner gain set to %f dB.\n", gain/10.0);
  	}
  
  	/* Reset endpoint before we start reading from it (mandatory) */
  	r = rtlsdr_reset_buffer(dev);
  	if (r < 0)
  		fprintf(stderr, "WARNING: Failed to reset buffers.\n");
  
  	pthread_mutex_init(&exit_cond_lock, NULL);
  	pthread_mutex_init(&ll_mutex, NULL);
  	pthread_mutex_init(&exit_cond_lock, NULL);
  	pthread_cond_init(&cond, NULL);
  	pthread_cond_init(&exit_cond, NULL);
  
  	memset(&local,0,sizeof(local));
  	local.sin_family = AF_INET;
  	local.sin_port = htons(port);
  	local.sin_addr.s_addr = inet_addr(addr);
  
  	listensocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
  	r = 1;
  	setsockopt(listensocket, SOL_SOCKET, SO_REUSEADDR, (char *)&r, sizeof(int));
  	setsockopt(listensocket, SOL_SOCKET, SO_LINGER, (char *)&ling, sizeof(ling));
  	bind(listensocket,(struct sockaddr *)&local,sizeof(local));
  
  #ifdef _WIN32
  	ioctlsocket(listensocket, FIONBIO, &blockmode);
  #else
  	r = fcntl(listensocket, F_GETFL, 0);
  	r = fcntl(listensocket, F_SETFL, r | O_NONBLOCK);
  #endif
  
  	while(1) {
  		printf("listening...\n");
  		printf("Use the device argument 'rtl_tcp=%s:%d' in OsmoSDR "
  		       "(gr-osmosdr) source\n"
  		       "to receive samples in GRC and control "
  		       "rtl_tcp parameters (frequency, gain, ...).\n",
  		       addr, port);
  		listen(listensocket,1);
  
  		while(1) {
  			FD_ZERO(&readfds);
  			FD_SET(listensocket, &readfds);
  			tv.tv_sec = 1;
  			tv.tv_usec = 0;
  			r = select(listensocket+1, &readfds, NULL, NULL, &tv);
  			if(do_exit) {
  				goto out;
  			} else if(r) {
  				rlen = sizeof(remote);
  				s = accept(listensocket,(struct sockaddr *)&remote, &rlen);
  				break;
  			}
  		}
  
  		setsockopt(s, SOL_SOCKET, SO_LINGER, (char *)&ling, sizeof(ling));
  
  		printf("client accepted!\n");
  
  		memset(&dongle_info, 0, sizeof(dongle_info));
  		memcpy(&dongle_info.magic, "RTL0", 4);
  
  		r = rtlsdr_get_tuner_type(dev);
  		if (r >= 0)
  			dongle_info.tuner_type = htonl(r);
  
  		r = rtlsdr_get_tuner_gains(dev, NULL);
  		if (r >= 0)
  			dongle_info.tuner_gain_count = htonl(r);
  
  		r = send(s, (const char *)&dongle_info, sizeof(dongle_info), 0);
  		if (sizeof(dongle_info) != r)
  			printf("failed to send dongle information\n");
  
  		pthread_attr_init(&attr);
  		pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
  		r = pthread_create(&tcp_worker_thread, &attr, tcp_worker, NULL);
  		r = pthread_create(&command_thread, &attr, command_worker, NULL);
  		pthread_attr_destroy(&attr);
  
  		r = rtlsdr_read_async(dev, rtlsdr_callback, NULL, buf_num, 0);
  
  		pthread_join(tcp_worker_thread, &status);
  		pthread_join(command_thread, &status);
  
  		closesocket(s);
  
  		printf("all threads dead..\n");
  		curelem = ll_buffers;
  		ll_buffers = 0;
  
  		while(curelem != 0) {
  			prev = curelem;
  			curelem = curelem->next;
  			free(prev->data);
  			free(prev);
  		}
  
  		do_exit = 0;
  		global_numq = 0;
  	}
  
  out:
  	rtlsdr_close(dev);
  	closesocket(listensocket);
  	closesocket(s);
  #ifdef _WIN32
  	WSACleanup();
  #endif
  	printf("bye!\n");
  	return r >= 0 ? r : -r;
  }
  