/*
 * $Id: ntripserver.c,v 1.34 2007/08/30 14:52:43 stuerze Exp $
 *
 * Copyright (c) 2003...2007
 * German Federal Agency for Cartography and Geodesy (BKG)
 *
 * Developed for Networked Transport of RTCM via Internet Protocol (NTRIP)
 * for streaming GNSS data over the Internet.
 *
 * Designed by Informatik Centrum Dortmund http://www.icd.de
 *
 * The BKG disclaims any liability nor responsibility to any person or
 * entity with respect to any loss or damage caused, or alleged to be
 * caused, directly or indirectly by the use and application of the NTRIP
 * technology.
 *
 * For latest information and updates, access:
 * http://igs.bkg.bund.de/index_ntrip_down.htm
 *
 * BKG, Frankfurt, Germany, February 2007
 * E-mail: euref-ip@bkg.bund.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, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/* CVS revision and version */
static char revisionstr[] = "$Revision: 1.34 $";
static char datestr[]     = "$Date: 2007/08/30 14:52:43 $";

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <netdb.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/termios.h>
#include <sys/types.h>
#include <sys/time.h>

#ifndef COMPILEDATE
#define COMPILEDATE " built " __DATE__
#endif

#ifndef MSG_DONTWAIT
#define MSG_DONTWAIT 0 /* prevent compiler errors */
#endif
#ifndef O_EXLOCK
#define O_EXLOCK 0 /* prevent compiler errors */
#endif

enum MODE { SERIAL = 1, TCPSOCKET = 2, INFILE = 3, SISNET = 4, UDPSOCKET = 5,
CASTER = 6, LAST };

enum OUTMODE { HTTP = 1, RTSP = 2, NTRIP1 = 3, END };

#define AGENTSTRING     "NTRIP NtripServerPOSIX"
#define BUFSZ           1024
#define SZ              64

/* default socket source */
#define SERV_HOST_ADDR  "localhost"
#define SERV_TCP_PORT   2101

/* default destination */
#define NTRIP_CASTER    "www.euref-ip.net"
#define NTRIP_PORT      2101

/* default sisnet source */
#define SISNET_SERVER   "131.176.49.142"
#define SISNET_PORT     7777

#define ALARMTIME       60

#define RTP_VERSION     2
#define TIME_RESOLUTION 125

static int ttybaud             = 19200;
static const char *ttyport     = "/dev/gps";
static const char *filepath    = "/dev/stdin";
static enum MODE inputmode     = INFILE;
static int sisnet              = 31;
static int gpsfd               = -1;
static int socket_tcp          = -1;
static int socket_udp          = -1;
static int sigint_received     = 0;
static int sigalarm_received   = 0;
static int sigpipe_received    = 0;
static int reconnect_sec       = 1;


/* Forward references */
static int  openserial(const char * tty, int blocksz, int baud);
static void send_receive_loop(int sock, int fd, int outmode,
  struct sockaddr * pcasterRTP, socklen_t length);
static void usage(int, char *);
static int  encode(char *buf, int size, const char *user, const char *pwd);
static int  send_to_caster(char *input, int socket, int input_size);
static void close_session(const char *caster_addr, const char *mountpoint, 
  int cseq, int session, char *rtsp_ext, int fallback);
static int  reconnect(int rec_sec, int rec_sec_max);

/* Signal Handling */
static void handle_sigint(int sig);
static void handle_alarm(int sig);
static void handle_sigpipe(int sig);
static void setup_signal_handler(int sig, void (*handler)(int));

/*
* main
*
* Main entry point for the program.  Processes command-line arguments and
* prepares for action.
*
* Parameters:
*     argc : integer        : Number of command-line arguments.
*     argv : array of char  : Command-line arguments as an array of
*                             zero-terminated pointers to strings.
*
* Return Value:
*     The function does not return a value (although its return type is int).
*
* Remarks:
*
*/

int main(int argc, char **argv)
{
  int                c;
  int                size = 2048; /* for setting send buffer size */
  struct             sockaddr_in caster;
  const char *       proxyhost = "";
  unsigned int       proxyport = 0;
  /*** INPUT ***/
  const char *       casterinhost = 0;
  unsigned int       casterinport = 0;
  const char *       inhost = 0;
  unsigned int       inport = 0;

  char               get_extension[SZ] = "";

  struct hostent *   he;
  const char *       mountpoint = NULL;

  const char *       sisnetpassword = "";
  const char *       sisnetuser = "";

  const char *       stream_name = 0;
  const char *       stream_user = 0;
  const char *       stream_password = 0;

  const char *       recvrid= 0;
  const char *       recvrpwd = 0;

  const char *       initfile = NULL;

  int                bindmode = 0;

  /*** OUTPUT ***/
  const char *       casterouthost = NTRIP_CASTER;
  unsigned int       casteroutport = NTRIP_PORT;
  const char *       outhost = 0;
  unsigned int       outport = 0;
  char               post_extension[SZ] = "";
  char               rtsp_extension[SZ] = "";

  const char *       ntrip_str = "";

  const char *       user = "";
  const char *       password = "";

  int                outputmode = NTRIP1;

  struct sockaddr_in casterRTP;
  struct sockaddr_in local;
  int                client_port = 0;
  int                server_port = 0;
  int                session = 0;
  int                cseq = 0;
  socklen_t          len = 0;
  int                i = 0;

  char               szSendBuffer[BUFSZ];
  char               authorization[SZ];
  int                nBufferBytes = 0;
  char *             dlim = " \r\n=";
  char *             token;
  char *             tok_buf[BUFSZ];

  int                reconnect_sec_max = 0;

  setbuf(stdout, 0);
  setbuf(stdin, 0);
  setbuf(stderr, 0);

  {
  char *a;
  int i = 0;
  for(a = revisionstr+11; *a && *a != ' '; ++a)
    revisionstr[i++] = *a;
  revisionstr[i] = 0;
  datestr[0] = datestr[7];
  datestr[1] = datestr[8];
  datestr[2] = datestr[9];
  datestr[3] = datestr[10];
  datestr[5] = datestr[12];
  datestr[6] = datestr[13];
  datestr[8] = datestr[15];
  datestr[9] = datestr[16];
  datestr[4] = datestr[7] = '-';
  datestr[10] = 0;
  }

  /* setup signal handler for timeout */
  setup_signal_handler(SIGALRM, handle_alarm);
  alarm(ALARMTIME);

  /* setup signal handler for CTRL+C */
  setup_signal_handler(SIGINT, handle_sigint);
  
/* setup signal handler for boken pipe */
  setup_signal_handler(SIGPIPE, handle_sigpipe);

  /* get and check program arguments */
  if(argc <= 1)
  {
    usage(2, argv[0]);
    exit(1);
  }
  while((c = getopt(argc, argv,
  "M:i:h:b:p:s:a:m:c:H:P:f:x:y:l:u:V:D:U:W:O:E:F:R:N:n:B")) != EOF)
  {
    switch (c)
    {
    case 'M': /*** InputMode ***/
      if(!strcmp(optarg, "serial"))         inputmode = SERIAL;
      else if(!strcmp(optarg, "tcpsocket")) inputmode = TCPSOCKET;
      else if(!strcmp(optarg, "file"))      inputmode = INFILE;
      else if(!strcmp(optarg, "sisnet"))    inputmode = SISNET;
      else if(!strcmp(optarg, "udpsocket")) inputmode = UDPSOCKET;
      else if(!strcmp(optarg, "caster"))    inputmode = CASTER;
      else inputmode = atoi(optarg);
      if((inputmode == 0) || (inputmode >= LAST))
      {
        fprintf(stderr, "ERROR: can't convert <%s> to a valid InputMode\n",
        optarg);
        usage(-1, argv[0]);
      }
      break;
    case 'i': /* serial input device */
      ttyport = optarg;
      break;
    case 'B': /* bind to incoming UDP stream */
      bindmode = 1;
      break;
    case 'V': /* Sisnet data server version number */
      if(!strcmp("3.0", optarg))      sisnet = 30;
      else if(!strcmp("3.1", optarg)) sisnet = 31;
      else if(!strcmp("2.1", optarg)) sisnet = 21;
      else
      {
        fprintf(stderr, "ERROR: unknown SISNeT version <%s>\n", optarg);
        usage(-2, argv[0]);
      }
      break;
    case 'b': /* serial input baud rate */
      ttybaud = atoi(optarg);
      if(ttybaud <= 1)
      {
        fprintf(stderr, "ERROR: can't convert <%s> to valid serial baud rate\n",
          optarg);
        usage(1, argv[0]);
      }
      break;
    case 'a': /* Destination caster address */
      casterouthost = optarg;
      break;
    case 'p': /* Destination caster port */
      casteroutport = atoi(optarg);
      if(casteroutport <= 1 || casteroutport > 65535)
      {
        fprintf(stderr,
          "ERROR: can't convert <%s> to a valid HTTP server port\n", optarg);
        usage(1, argv[0]);
      }
      break;
    case 'm': /* Destination caster mountpoint for stream upload */
      mountpoint = optarg;
      break;
    case 's': /* File name for input data simulation from file */
      filepath = optarg;
      break;
    case 'f': /* name of an initialization file */
      initfile = optarg;
      break;
    case 'x': /* user ID to access incoming stream */
      recvrid = optarg;
      break;
    case 'y': /* password to access incoming stream */
      recvrpwd = optarg;
      break;
    case 'u': /* Sisnet data server user ID */
      sisnetuser = optarg;
      break;
    case 'l': /* Sisnet data server password */
      sisnetpassword = optarg;
      break;
    case 'c': /* DestinationCaster password for stream upload to mountpoint */
      password = optarg;
      break;
    case 'H': /* Input host address*/
      casterinhost = optarg;
      break;
    case 'P': /* Input port */
      casterinport = atoi(optarg);
      if(casterinport <= 1 || casterinport > 65535)
      {
        fprintf(stderr, "ERROR: can't convert <%s> to a valid port number\n",
          optarg);
        usage(1, argv[0]);
      }
      break;
    case 'D': /* Source caster mountpoint for stream input */
     stream_name = optarg;
     break;
    case 'U': /* Source caster user ID for input stream access */
     stream_user = optarg;
     break;
    case 'W': /* Source caster password for input stream access */
     stream_password = optarg;
     break;
    case 'E': /* Proxy Server */
      proxyhost = optarg;
      break;
    case 'F': /* Proxy port */
      proxyport = atoi(optarg);
      break;
    case 'R':  /* maximum delay between reconnect attempts in seconds */
       reconnect_sec_max = atoi(optarg);
       break;
    case 'O': /* OutputMode */
      outputmode = 0;
      if (!strcmp(optarg,"n") || !strcmp(optarg,"ntrip1"))
        outputmode = NTRIP1;
      else if(!strcmp(optarg,"h") || !strcmp(optarg,"http"))
        outputmode = HTTP;
      else if(!strcmp(optarg,"r") || !strcmp(optarg,"rtsp"))
        outputmode = RTSP;
      else outputmode = atoi(optarg);
      if((outputmode == 0) || (outputmode >= END))
      {
        fprintf(stderr, "ERROR: can't convert <%s> to a valid OutputMode\n",
        optarg);
        usage(-1, argv[0]);
      }
      break;
    case 'n': /* Destination caster user ID for stream upload to mountpoint */
      user = optarg;
      break;
    case 'N': /* Ntrip-STR, optional for Ntrip Version 2.0 */
      ntrip_str = optarg;
      break;
    case 'h': /* print help screen */
    case '?':
      usage(0, argv[0]);
      break;
    default:
      usage(2, argv[0]);
      break;
    }
  }

  argc -= optind;
  argv += optind;

  /*** argument analysis ***/
  if(argc > 0)
  {
    fprintf(stderr, "ERROR: Extra args on command line: ");
    for(; argc > 0; argc--)
    {
      fprintf(stderr, " %s", *argv++);
    }
    fprintf(stderr, "\n");
    usage(1, argv[0]);                   /* never returns */
  }

  if(outputmode != NTRIP1)
  {
     fprintf(stderr, "\nWARNING: *** NTRIP VERSION 2 PROTOCOL IS STILL"
      " BETA AND MAY BE CHANGED ***\n\n");
  }
  
  if(*ntrip_str && (outputmode == NTRIP1))
  {
     fprintf(stderr, "WARNING: OutputMode is Ntrip version 1.0"
     " - Ntrip-STR will not be considered\n");
  }

  if((reconnect_sec_max > 0) && (reconnect_sec_max < 256))
  {
    fprintf(stderr,
    "WARNING: maximum delay between reconnect attemts changed from %d to 256 seconds\n"
    , reconnect_sec_max);
    reconnect_sec_max = 256;
  }

  if(!mountpoint)
  {
    fprintf(stderr, "ERROR: Missing mountpoint argument for stream upload\n");
    exit(1);
  }

  if(!password[0])
  {
    fprintf(stderr, "WARNING: Missing password argument for stream upload - "
    "are you really sure?\n");
  }
  else
  {
    nBufferBytes += encode(authorization, sizeof(authorization), user,
    password);
    if(nBufferBytes > (int)sizeof(authorization))
    {
      fprintf(stderr, "ERROR: user ID and/or password too long: %d (%d)\n"
      "       user ID: %s \npassword: <%s>\n",
      nBufferBytes, (int)sizeof(authorization), user, password);
      exit(1);
    }
  }

  if(stream_name && stream_user && !stream_password)
  {
    fprintf(stderr, "WARNING: Missing password argument for stream download"
      " - are you really sure?\n");
  }

  /*** proxy server handling ***/
  if(*proxyhost)
  {
    outhost = inhost = proxyhost;
    outport = inport = proxyport;
    i = snprintf(szSendBuffer, sizeof(szSendBuffer),"http://%s:%d",
    casterouthost, casteroutport);
    if((i > SZ) || (i < 0))
    {
      fprintf(stderr, "ERROR: Destination caster name/port to long - "
      "length = %d (max: %d)\n", i, SZ);
      exit(0);
    }
    else
    {
      strncpy(post_extension, szSendBuffer, (size_t)i);
      strcpy(szSendBuffer, "");
      i = snprintf(szSendBuffer, sizeof(szSendBuffer),":%d", casteroutport);
      strncpy(rtsp_extension, szSendBuffer, SZ);
      strcpy(szSendBuffer,""); i = 0;
    }
    i = snprintf(szSendBuffer, sizeof(szSendBuffer),"http://%s:%d", casterinhost, casterinport);
    if((i > SZ) || (i < 0))
    {
      fprintf(stderr,"ERROR: Destination caster name/port to long - length = %d (max: %d)\n", i, SZ);
      exit(0);
    }
    else
    {
      strncpy(get_extension, szSendBuffer, (size_t)i);
      strcpy(szSendBuffer, "");
      i = 0;
    }
  }
  else
  {
    outhost   = casterouthost; outport = casteroutport;
    inhost    = casterinhost;  inport  = casterinport;
  }

  while(inputmode != LAST)
  {
    int input_init = 1;
    /*** InputMode handling ***/
    switch(inputmode)
    {
    case INFILE:
      {
	if((gpsfd = open(filepath, O_RDONLY)) < 0)
	{
          perror("ERROR: opening input file");
          exit(1);
	}
	/* set blocking inputmode in case it was not set
          (seems to be sometimes for fifo's) */
	fcntl(gpsfd, F_SETFL, 0);
	printf("file input: file = %s\n", filepath);
      }
      break;
    case SERIAL: /* open serial port */
      {
	gpsfd = openserial(ttyport, 1, ttybaud);
	if(gpsfd < 0)
	{
          exit(1);
	}
	printf("serial input: device = %s, speed = %d\n", ttyport, ttybaud);
      }
      break;
    case TCPSOCKET: case UDPSOCKET: case SISNET: case CASTER:
      {
	if(inputmode == SISNET)
	{
          if(!inhost) inhost = SISNET_SERVER;
          if(!inport) inport = SISNET_PORT;
	}
	else if(inputmode == CASTER)
	{
          if(!inport) inport = NTRIP_PORT;
          if(!inhost) inhost = NTRIP_CASTER;
	}
	else if((inputmode == TCPSOCKET) || (inputmode == UDPSOCKET))
	{
          if(!inport) inport = SERV_TCP_PORT;
          if(!inhost) inhost = SERV_HOST_ADDR;
	}

	if(!(he = gethostbyname(inhost)))
	{
          fprintf(stderr, "ERROR: Input host <%s> unknown\n", inhost);
          usage(-2, argv[0]);
	}

	if((gpsfd = socket(AF_INET, inputmode == UDPSOCKET
	? SOCK_DGRAM : SOCK_STREAM, 0)) < 0)
	{
          fprintf(stderr,
          "ERROR: can't create socket for incoming data stream\n");
          exit(1);
	}

	memset((char *) &caster, 0x00, sizeof(caster));
	if(!bindmode)
          memcpy(&caster.sin_addr, he->h_addr, (size_t)he->h_length);
	caster.sin_family = AF_INET;
	caster.sin_port = htons(inport);

	fprintf(stderr, "%s input: host = %s, port = %d, %s%s%s%s%s\n",
	inputmode == CASTER ? "caster" : inputmode == SISNET ? "sisnet" :
	inputmode == TCPSOCKET ? "tcp socket" : "udp socket",
	bindmode ? "127.0.0.1" : inet_ntoa(caster.sin_addr),
	inport, stream_name ? "stream = " : "", stream_name ? stream_name : "",
	initfile ? ", initfile = " : "", initfile ? initfile : "",
	bindmode ? "binding mode" : "");

	if(bindmode)
	{
          if(bind(gpsfd, (struct sockaddr *) &caster, sizeof(caster)) < 0)
          {
            fprintf(stderr, "ERROR: can't bind input to port %d\n", inport);
            reconnect_sec_max = 0;
            input_init = 0;
            break;
          }
	} /* connect to input-caster or proxy server*/
	else if(connect(gpsfd, (struct sockaddr *)&caster, sizeof(caster)) < 0)
	{
          fprintf(stderr, "WARNING: can't connect input to %s at port %d\n",
          inet_ntoa(caster.sin_addr), inport);
          input_init = 0;
          break;
	}

	if(stream_name) /* input from Ntrip Version 1.0 caster*/
	{
          int init = 0;

          /* set socket buffer size */
          setsockopt(gpsfd, SOL_SOCKET, SO_SNDBUF, (const char *) &size,
            sizeof(const char *));
          if(stream_user && stream_password)
          {
            /* leave some space for login */
            nBufferBytes=snprintf(szSendBuffer, sizeof(szSendBuffer)-40,
            "GET %s/%s HTTP/1.0\r\n"
            "User-Agent: %s/%s\r\n"
            "Authorization: Basic ", get_extension, stream_name,
            AGENTSTRING, revisionstr);
            /* second check for old glibc */
            if(nBufferBytes > (int)sizeof(szSendBuffer)-40 || nBufferBytes < 0)
            {
              fprintf(stderr, "ERROR: Source caster request too long\n");
              input_init = 0;
              reconnect_sec_max =0;
              break;
            }
            nBufferBytes += encode(szSendBuffer+nBufferBytes,
              sizeof(szSendBuffer)-nBufferBytes-4, stream_user, stream_password);
            if(nBufferBytes > (int)sizeof(szSendBuffer)-4)
            {
              fprintf(stderr,
              "ERROR: Source caster user ID and/or password too long\n");
              input_init = 0;
              reconnect_sec_max =0;
              break;
            }              
            szSendBuffer[nBufferBytes++] = '\r';
            szSendBuffer[nBufferBytes++] = '\n';
            szSendBuffer[nBufferBytes++] = '\r';
            szSendBuffer[nBufferBytes++] = '\n';
          }
          else
          {
            nBufferBytes = snprintf(szSendBuffer, sizeof(szSendBuffer),
            "GET %s/%s HTTP/1.0\r\n"
            "User-Agent: %s/%s\r\n"
            "\r\n", get_extension, stream_name, AGENTSTRING, revisionstr);
          }
          if((send(gpsfd, szSendBuffer, (size_t)nBufferBytes, 0))
          != nBufferBytes)
          {
            fprintf(stderr, "WARNING: could not send Source caster request\n");
            input_init = 0;
            break;
          }
          nBufferBytes = 0;
          /* check Source caster's response */
          while(!init && nBufferBytes < (int)sizeof(szSendBuffer)
          && (nBufferBytes += recv(gpsfd, szSendBuffer,
          sizeof(szSendBuffer)-nBufferBytes, 0)) > 0)
          {
            if(strstr(szSendBuffer, "\r\n"))
            {              
              if(strncmp(szSendBuffer, "ICY 200 OK", 10))
              {
                int k;
                fprintf(stderr,
                "ERROR: could not get requested data from Source caster: ");
                for(k = 0; k < nBufferBytes && szSendBuffer[k] != '\n'
                  && szSendBuffer[k] != '\r'; ++k)
                {
                  fprintf(stderr, "%c", isprint(szSendBuffer[k])
                  ? szSendBuffer[k] : '.');
        	}
                fprintf(stderr, "\n");
                if(strncmp(szSendBuffer, "SOURCETABLE 200 OK",18))
                {
                  reconnect_sec_max =0;
                }
                input_init = 0;
                break;
              }
              else init = 1;
            }
          }
	} /* end input from Ntrip Version 1.0 caster */

	if(initfile && inputmode != SISNET)
	{
          char buffer[1024];
          FILE *fh;
          int i;

          if((fh = fopen(initfile, "r")))
          {
            while((i = fread(buffer, 1, sizeof(buffer), fh)) > 0)
            {
              if((send(gpsfd, buffer, (size_t)i, 0)) != i)
              {
        	perror("WARNING: sending init file");
        	input_init = 0;
        	break;
              }
            }
            if(i < 0)
            {
              perror("ERROR: reading init file");
              reconnect_sec_max = 0;
              input_init = 0;
              break;
            }
            fclose(fh);
          }
          else
          {
            fprintf(stderr, "ERROR: can't read init file <%s>\n", initfile);
            reconnect_sec_max = 0;
            input_init = 0;
            break;
          }
	}
      }
      if(inputmode == SISNET)
      {
	int i, j;
	char buffer[1024];

	i = snprintf(buffer, sizeof(buffer), sisnet >= 30 ? "AUTH,%s,%s\r\n"
          : "AUTH,%s,%s", sisnetuser, sisnetpassword);
	if((send(gpsfd, buffer, (size_t)i, 0)) != i)
	{
          perror("WARNING: sending authentication for SISNeT data server");
          input_init = 0;
          break;
	}
	i = sisnet >= 30 ? 7 : 5;
	if((j = recv(gpsfd, buffer, i, 0)) != i && strncmp("*AUTH", buffer, 5))
	{
          fprintf(stderr, "WARNING: SISNeT connect failed:");
          for(i = 0; i < j; ++i)
          {
            if(buffer[i] != '\r' && buffer[i] != '\n')
            {
              fprintf(stderr, "%c", isprint(buffer[i]) ? buffer[i] : '.');
            }
          }
          fprintf(stderr, "\n");
          input_init = 0;
          break;
	}
	if(sisnet >= 31)
	{
          if((send(gpsfd, "START\r\n", 7, 0)) != i)
          {
            perror("WARNING: sending Sisnet start command");
            input_init = 0;
            break;
          }
	}
      }
      /*** receiver authentication  ***/
      if (recvrid && recvrpwd && ((inputmode == TCPSOCKET)
      || (inputmode == UDPSOCKET)))
      {
	if (strlen(recvrid) > (BUFSZ-3))
	{
          fprintf(stderr, "ERROR: Receiver ID too long\n");
          reconnect_sec_max = 0;
          input_init = 0;
          break;
	}
	else
	{
          fprintf(stderr, "Sending user ID for receiver...\n");
          nBufferBytes = read(gpsfd, szSendBuffer, BUFSZ);
          strcpy(szSendBuffer, recvrid);
          strcat(szSendBuffer,"\r\n");
          if(send(gpsfd,szSendBuffer, strlen(szSendBuffer), MSG_DONTWAIT) < 0)
          {
            perror("WARNING: sending user ID for receiver");
            input_init = 0;
            break;
          }
	}

	if (strlen(recvrpwd) > (BUFSZ-3))
	{
          fprintf(stderr, "ERROR: Receiver password too long\n"); 
          reconnect_sec_max = 0;
          input_init = 0;
          break;
	}
	else
	{
          fprintf(stderr, "Sending user password for receiver...\n");
          nBufferBytes = read(gpsfd, szSendBuffer, BUFSZ);
          strcpy(szSendBuffer, recvrpwd);
          strcat(szSendBuffer,"\r\n");
          if(send(gpsfd, szSendBuffer, strlen(szSendBuffer), MSG_DONTWAIT) < 0)
          {
            perror("WARNING: sending user password for receiver");
            input_init = 0;
            break;
          }
	}
      }
      break;
    default:
      usage(-1, argv[0]);
      break;
    }
    
    /* ----- main part ----- */
    int output_init = 1;

    while((input_init) && (output_init))
    {
      if((sigint_received) || (sigalarm_received) || (sigpipe_received)) break;

      if(!(he = gethostbyname(outhost)))
      {
	fprintf(stderr, "ERROR: Destination caster or proxy host <%s> unknown\n",
	outhost);
        close_session(casterouthost, mountpoint, cseq, session, rtsp_extension, 0);
	usage(-2, argv[0]);
      }

      /* create socket */
      if((socket_tcp = socket(AF_INET, SOCK_STREAM, 0)) < 0)
      {
	perror("ERROR: tcp socket");
        reconnect_sec_max = 0;
        break;
      }

      memset((char *) &caster, 0x00, sizeof(caster));
      memcpy(&caster.sin_addr, he->h_addr, (size_t)he->h_length);
      caster.sin_family = AF_INET;
      caster.sin_port = htons(outport);

      /* connect to Destination caster or Proxy server*/
      fprintf(stderr, "caster output: host = %s, port = %d, mountpoint = %s"
      ", mode = %s\n\n", inet_ntoa(caster.sin_addr), outport, mountpoint,
      outputmode == NTRIP1 ? "ntrip1" : outputmode == HTTP ? "http" : "rtsp");

      if(connect(socket_tcp, (struct sockaddr *) &caster, sizeof(caster)) < 0)
      {
	fprintf(stderr, "WARNING: can't connect output to %s at port %d\n",
          inet_ntoa(caster.sin_addr), outport);
        break;
      }

      /*** OutputMode handling ***/
      switch(outputmode)
      {
	case NTRIP1: /*** OutputMode Ntrip Version 1.0 ***/
          nBufferBytes = snprintf(szSendBuffer, sizeof(szSendBuffer),
            "SOURCE %s %s/%s\r\n"
            "Source-Agent: %s/%s\r\n\r\n",
            password, post_extension, mountpoint, AGENTSTRING, revisionstr);
          if((nBufferBytes > (int)sizeof(szSendBuffer)) || (nBufferBytes < 0))
          {
            fprintf(stderr, "ERROR: Destination caster request to long\n");
            reconnect_sec_max = 0;
            output_init = 0;
            break;
          }
          if(!send_to_caster(szSendBuffer, socket_tcp, nBufferBytes))
          {
            output_init = 0;
            break;
          }
          /* check Destination caster's response */
          nBufferBytes = recv(socket_tcp, szSendBuffer, sizeof(szSendBuffer), 0);
          szSendBuffer[nBufferBytes] = '\0';
          if(!strstr(szSendBuffer, "OK"))
          {
            char *a;
            fprintf(stderr,
            "ERROR: Destination caster's or Proxy's reply is not OK: ");
            for(a = szSendBuffer; *a && *a != '\n' && *a != '\r'; ++a)
            {
              fprintf(stderr, "%.1s", isprint(*a) ? a : ".");
            }
            fprintf(stderr, "\n");
            if((strstr(szSendBuffer,"ERROR - Bad Password"))
            || (strstr(szSendBuffer,"400 Bad Request")))           
            reconnect_sec_max = 0;
            output_init = 0;
            break;
          }
#ifndef NDEBUG
          else
          {
            fprintf(stderr, "Destination caster response:\n%s\n",
            szSendBuffer);
          }
#endif
          send_receive_loop(socket_tcp, gpsfd, outputmode, NULL, 0);
          break;
	case HTTP: /*** Ntrip-Version 2.0 HTTP/1.1 ***/
          nBufferBytes = snprintf(szSendBuffer, sizeof(szSendBuffer),
            "POST %s/%s HTTP/1.1\r\n"
            "Host: %s\r\n"
            "Ntrip-Version: Ntrip/2.0\r\n"
            "User-Agent: %s/%s\r\n"
            "Authorization: Basic %s\r\n"
            "Ntrip-STR: %s\r\n"
            "Transfer-Encoding: chunked\r\n\r\n",
            post_extension, mountpoint, casterouthost, AGENTSTRING,
            revisionstr, authorization, ntrip_str);
          if((nBufferBytes > (int)sizeof(szSendBuffer)) || (nBufferBytes < 0))
          {
            fprintf(stderr, "ERROR: Destination caster request to long\n");
            reconnect_sec_max = 0;
            output_init = 0;
            break;
          }
          if(!send_to_caster(szSendBuffer, socket_tcp, nBufferBytes))
          {
            output_init = 0;
            break;
          }
          /* check Destination caster's response */
          nBufferBytes = recv(socket_tcp, szSendBuffer, sizeof(szSendBuffer), 0);
          szSendBuffer[nBufferBytes] = '\0';
          if(!strstr(szSendBuffer, "HTTP/1.1 200 OK"))
          {
            char *a;
            fprintf(stderr,
            "ERROR: Destination caster's%s reply is not OK: ",
            *proxyhost ? " or Proxy's" : "");
            for(a = szSendBuffer; *a && *a != '\n' && *a != '\r'; ++a)
            {
              fprintf(stderr, "%.1s", isprint(*a) ? a : ".");
            }
            fprintf(stderr, "\n");
            /* fallback if necessary */
            if(!strstr(szSendBuffer,"Ntrip-Version: Ntrip/2.0\r\n"))
            {
              fprintf(stderr,
              "       Ntrip Version 2.0 not implemented at Destination caster"
              " <%s>%s%s%s\n%s\n"
              "ntripserver falls back to Ntrip Version 1.0\n\n",
              casterouthost,
              *proxyhost ? " or Proxy <" : "", proxyhost, *proxyhost ? ">" : "",
              *proxyhost ? "       or HTTP/1.1 not implemented at Proxy\n" : "");
              close_session(casterouthost, mountpoint, cseq, session, rtsp_extension, 1);
              outputmode = NTRIP1;
              break;
            }
            else if((strstr(szSendBuffer,"HTTP/1.1 401 Unauthorized"))
            || (strstr(szSendBuffer,"501 Not Implemented")))
            {
               reconnect_sec_max = 0;
            }
            output_init = 0;
            break;
          }
#ifndef NDEBUG
          else
          {
            fprintf(stderr, "Destination caster response:\n%s\n",szSendBuffer);
          }
#endif
          send_receive_loop(socket_tcp, gpsfd, outputmode, NULL, 0);
          break;
	case RTSP: /*** Ntrip-Version 2.0 RTSP / RTP ***/
          if((socket_udp = socket(AF_INET, SOCK_DGRAM,0)) < 0)
          {
            perror("ERROR: udp socket");
            exit(4);
          }
          /* fill structure with local address information for UDP */
          memset(&local, 0, sizeof(local));
          local.sin_family = AF_INET;
          local.sin_port = htons(0);
          local.sin_addr.s_addr = htonl(INADDR_ANY);
          len = (socklen_t)sizeof(local);
          /* bind() in order to get a random RTP client_port */
          if((bind(socket_udp,(struct sockaddr *)&local, len)) < 0)
          {
            perror("ERROR: udp bind");
            reconnect_sec_max = 0;
            output_init = 0;
            break;
          }
          if((getsockname(socket_udp, (struct sockaddr*)&local, &len)) != -1)
          {
            client_port = (unsigned int)ntohs(local.sin_port);
          }
          else
          {
            perror("ERROR: getsockname(localhost)");
            reconnect_sec_max = 0;
            output_init = 0;
            break;
          }
          nBufferBytes = snprintf(szSendBuffer, sizeof(szSendBuffer),
            "SETUP rtsp://%s%s/%s RTSP/1.0\r\n"
            "CSeq: 1\r\n"
            "Ntrip-Version: Ntrip/2.0\r\n"
            "Ntrip-Component: Ntripserver\r\n"
            "User-Agent: %s/%s\r\n"
            "Transport: RTP/GNSS;unicast;client_port=%u\r\n"
            "Authorization: Basic %s\r\n"
            "Ntrip-STR: %s\r\n\r\n",
            casterouthost, rtsp_extension, mountpoint, AGENTSTRING, revisionstr,
            client_port, authorization, ntrip_str);
          if((nBufferBytes > (int)sizeof(szSendBuffer)) || (nBufferBytes < 0))
          {
            fprintf(stderr, "ERROR: Destination caster request to long\n");
            reconnect_sec_max = 0;
            output_init = 0;
            break;
          }
          if(!send_to_caster(szSendBuffer, socket_tcp, nBufferBytes))
          {
            output_init = 0;
            break;
          }
          while((nBufferBytes = recv(socket_tcp, szSendBuffer,
          sizeof(szSendBuffer), 0)) > 0)
          {
            /* check Destination caster's response */
            szSendBuffer[nBufferBytes] = '\0';
            if(!strstr(szSendBuffer, "RTSP/1.0 200 OK"))
            {
              char *a;
              fprintf(stderr,
              "ERROR: Destination caster's%s reply is not OK: ",
              *proxyhost ? " or Proxy's" : "");
              for(a = szSendBuffer; *a && *a != '\n' && *a != '\r'; ++a)
              {
        	fprintf(stderr, "%c", isprint(*a) ? *a : '.');
              }
              fprintf(stderr, "\n");
              /* fallback if necessary */
              if(strncmp(szSendBuffer, "RTSP",4) != 0)
              {
        	if(strstr(szSendBuffer,"Ntrip-Version: Ntrip/2.0\r\n"))
        	{
                  fprintf(stderr,
                  "       RTSP not implemented at Destination caster <%s>%s%s%s\n\n"
                  "ntripserver falls back to Ntrip Version 2.0 in TCP/IP"
                  " mode\n\n", casterouthost,
                  *proxyhost ? " or Proxy <" :"", proxyhost, *proxyhost ? ">":"");
                  close_session(casterouthost, mountpoint, cseq, session, rtsp_extension, 1);
                  outputmode = HTTP;
                  break;
        	}
        	else
        	{
                  fprintf(stderr,
                  "       Ntrip-Version 2.0 not implemented at Destination caster"
                  "<%s>%s%s%s\n%s"
                  "       or RTSP/1.0 not implemented at Destination caster%s\n\n"
                  "ntripserver falls back to Ntrip Version 1.0\n\n",
                  casterouthost, *proxyhost ? " or Proxy <" :"", proxyhost,
                  *proxyhost ? ">":"",
                  *proxyhost ? " or HTTP/1.1 not implemented at Proxy\n" : "",
                  *proxyhost ? " or Proxy" :"");
                  close_session(casterouthost, mountpoint, cseq, session, rtsp_extension, 1);
                  outputmode = NTRIP1;
                  break;
        	}
              }
              else if((strstr(szSendBuffer, "RTSP/1.0 401 Unauthorized"))
              || (strstr(szSendBuffer, "RTSP/1.0 501 Not Implemented")))
              {
                reconnect_sec_max = 0;
              }
              output_init = 0;
              break;
            }
#ifndef NDEBUG
            else
            {
              fprintf(stderr, "Destination caster response:\n%s\n",szSendBuffer);
            }
#endif
            if((strstr(szSendBuffer,"RTSP/1.0 200 OK\r\n"))
            && (strstr(szSendBuffer,"CSeq: 1\r\n")))
            {
              for(token = strtok(szSendBuffer, dlim); token != NULL;
              token = strtok(NULL, dlim))
              {
        	tok_buf[i] = token; i++;
              }
              session = atoi(tok_buf[6]);
              server_port = atoi(tok_buf[10]);
              nBufferBytes = snprintf(szSendBuffer, sizeof(szSendBuffer),
        	"POST rtsp://%s%s/%s RTSP/1.0\r\n"
        	"CSeq: 2\r\n"
        	"Session: %d\r\n"
        	"\r\n",
        	casterouthost, rtsp_extension,  mountpoint,  session);
              if((nBufferBytes >= (int)sizeof(szSendBuffer))
              || (nBufferBytes < 0))
              {
        	fprintf(stderr, "ERROR: Destination caster request to long\n");
                reconnect_sec_max = 0;
                output_init = 0;
        	break;
              }
              if(!send_to_caster(szSendBuffer, socket_tcp, nBufferBytes))
              {
                 output_init = 0;
        	 break;
              }
            }
            else if((strstr(szSendBuffer,"RTSP/1.0 200 OK\r\n")) && (strstr(szSendBuffer,
            "CSeq: 2\r\n"))) 
            {
              /* fill structure with caster address information for UDP */
              memset(&casterRTP, 0, sizeof(casterRTP));
              casterRTP.sin_family = AF_INET;
              casterRTP.sin_port   = htons(((uint16_t)server_port));
              if((he = gethostbyname(outhost))== NULL) 
              {
        	fprintf(stderr, "ERROR: Destination caster unknown\n");
                reconnect_sec_max = 0;
                output_init = 0;
                break;
              }
              else
              {
        	memcpy((char *)&casterRTP.sin_addr.s_addr,
        	he->h_addr_list[0], (size_t)he->h_length);
              }
              cseq = 2;
              len = (socklen_t)sizeof(casterRTP);
              send_receive_loop(socket_udp, gpsfd, outputmode, (struct sockaddr *)&casterRTP, 
              (socklen_t)len);
              break;
            }
            else{break;}
          }
          break;
      }     
    }
    close_session(casterouthost, mountpoint, cseq, session, rtsp_extension, 0);
    if((!sigint_received) && (reconnect_sec_max))
    {
       reconnect_sec = reconnect(reconnect_sec, reconnect_sec_max);
    }
    else inputmode = LAST;
  }
  return 0;
}

static void send_receive_loop(int sock, int fd, int outmode, struct sockaddr* pcasterRTP,
socklen_t length)
{
  int nodata = 0;
  char buffer[BUFSZ] = { 0 };
  char sisnetbackbuffer[200];
  char szSendBuffer[BUFSZ] = "";
  int nBufferBytes = 0;

   /* RTSP / RTP Mode */
  int    isfirstpacket = 1;
  struct timeval now;
  struct timeval last = {0,0};
  long int sendtimediff;
  int rtpseq = 0;
  int rtpssrc = 0;
  int rtptime = 0;

  /* data transmission */
  fprintf(stderr,"transfering data ...\n");
  int send_recv_success = 0;
  while(1)
  {
    if(send_recv_success < 3) send_recv_success++;  
    if(!nodata) alarm(ALARMTIME);
    else nodata = 0; 

    /* signal handling*/
    if((sigint_received) || (sigpipe_received) || (sigalarm_received)) break;
    
    if(!nBufferBytes)
    {
      if(inputmode == SISNET && sisnet <= 30)
      {
        int i;
        /* a somewhat higher rate than 1 second to get really each block */
        /* means we need to skip double blocks sometimes */
        struct timeval tv = {0,700000};
        select(0, 0, 0, 0, &tv);
        memcpy(sisnetbackbuffer, buffer, sizeof(sisnetbackbuffer));
        i = (sisnet >= 30 ? 5 : 3);
        if((send(gpsfd, "MSG\r\n", i, 0)) != i)
        {
          perror("WARNING: sending SISNeT data request failed");
          return;
        }
      }
      /*** receiving data ****/
      nBufferBytes = read(fd, buffer, sizeof(buffer));
      if(!nBufferBytes)
      {
        printf("WARNING: no data received from input\n");
        sleep(3);
        nodata = 1;
        continue;
      }
      else if((nBufferBytes < 0) && (!sigint_received))
      {
        perror("WARNING: reading input failed");
        return;
      }
      /* we can compare the whole buffer, as the additional bytes
         remain unchanged */
      if(inputmode == SISNET && sisnet <= 30 &&
      !memcmp(sisnetbackbuffer, buffer, sizeof(sisnetbackbuffer)))
      {
        nBufferBytes = 0;
      }
    }
    /**  send data ***/
    if((nBufferBytes)  && (outmode == NTRIP1)) /*** Ntrip-Version 1.0 ***/
    {
      int i;
      if((i = send(sock, buffer, (size_t)nBufferBytes, MSG_DONTWAIT))
      != nBufferBytes)
      {
        if(i < 0)
        {
          if(errno != EAGAIN)
          {
            perror("WARNING: could not send data to Destination caster");
            return;
          }
        }
        else if(i)
        {
          memmove(buffer, buffer+i, (size_t)(nBufferBytes-i));
          nBufferBytes -= i;
        }
      }else
      {
        nBufferBytes = 0;
      }
    }
    /*** Ntrip-Version 2.0 HTTP/1.1 ***/
    else if((nBufferBytes)  && (outmode == HTTP))
    {
      int i, nChunkBytes, j = 1;
      nChunkBytes = snprintf(szSendBuffer, sizeof(szSendBuffer),"%x\r\n",
      nBufferBytes);
      send(sock, szSendBuffer, nChunkBytes, MSG_DONTWAIT);
      if((i = send(sock, buffer, (size_t)nBufferBytes, MSG_DONTWAIT))
      != nBufferBytes)
      {
        if(i < 0)
        {
          if(errno != EAGAIN)
          {
            perror("WARNING: could not send data to Destination caster");
            return;
          }
        }
        else if(i)
        {
          while(j>0)
          {
            j = send(sock, buffer, (size_t)BUFSZ, MSG_DONTWAIT);
          }
        }
      }
      else
      {
        send(sock, "\r\n", strlen("\r\n"), MSG_DONTWAIT);
        nBufferBytes = 0;
      }
    }
    /*** Ntrip-Version 2.0 RTSP(TCP) / RTP(UDP) ***/
    else if((nBufferBytes)  && (outmode == RTSP))
    {
      char rtpbuffer[BUFSZ+12];
      int i, j;
      gettimeofday(&now, NULL);
      /* RTP data packet generation*/
      if(isfirstpacket){
        rtpseq = rand();
        rtptime = rand();
        rtpssrc = rand();
        last = now;
        isfirstpacket = 0;
      }
      else
      {
        ++rtpseq;
        sendtimediff = (((now.tv_sec - last.tv_sec)*1000000)
        + (now.tv_usec - last.tv_usec));
        rtptime += sendtimediff/TIME_RESOLUTION;
      }
      rtpbuffer[0] = (RTP_VERSION<<6);
      /* padding, extension, csrc are empty */
      rtpbuffer[1] = 96;
      /* marker is empty */
      rtpbuffer[2] = rtpseq>>8;
      rtpbuffer[3] = rtpseq;
      rtpbuffer[4] = rtptime>>24;
      rtpbuffer[5] = rtptime>>16;
      rtpbuffer[6] = rtptime>>8;
      rtpbuffer[7] = rtptime;
      rtpbuffer[8] = rtpssrc>>24;
      rtpbuffer[9] = rtpssrc>>16;
      rtpbuffer[10] = rtpssrc>>8;
      rtpbuffer[11] = rtpssrc;
      for(j=0; j<nBufferBytes; j++) {rtpbuffer[12+j] = buffer[j];}
      last.tv_sec  = now.tv_sec;
      last.tv_usec = now.tv_usec;

      if ((i = sendto(sock, rtpbuffer, 12 + nBufferBytes, 0, pcasterRTP,
      length)) != (nBufferBytes + 12))
      {
        if(i < 0)
        {
          if(errno != EAGAIN)
          {
            perror("WARNING: could not send data to Destination caster");
            return;
          }
        }
        else if(i)
        {
          memmove(buffer, buffer+(i-12), (size_t)(nBufferBytes-(i-12)));
          nBufferBytes -= i-12;
        }
      }
      else
      {
        nBufferBytes = 0;
      }
    }
    if(send_recv_success == 3) reconnect_sec = 1;
  }
  return;
}


/********************************************************************
 * openserial
 *
 * Open the serial port with the given device name and configure it for
 * reading NMEA data from a GPS receiver.
 *
 * Parameters:
 *     tty     : pointer to    : A zero-terminated string containing the device
 *               unsigned char   name of the appropriate serial port.
 *     blocksz : integer       : Block size for port I/O
 *     baud :    integer       : Baud rate for port I/O
 *
 * Return Value:
 *     The function returns a file descriptor for the opened port if successful.
 *     The function returns -1 in the event of an error.
 *
 * Remarks:
 *
 ********************************************************************/

static int openserial(const char * tty, int blocksz, int baud)
{
  int fd;
  struct termios termios;

  fd = open(tty, O_RDWR | O_NONBLOCK | O_EXLOCK);
  if(fd < 0)
  {
    perror("ERROR: opening serial connection");
    return (-1);
  }
  if(tcgetattr(fd, &termios) < 0)
  {
    perror("ERROR: get serial attributes");
    return (-1);
  }
  termios.c_iflag = 0;
  termios.c_oflag = 0;          /* (ONLRET) */
  termios.c_cflag = CS8 | CLOCAL | CREAD;
  termios.c_lflag = 0;
  {
    int cnt;
    for(cnt = 0; cnt < NCCS; cnt++)
      termios.c_cc[cnt] = -1;
  }
  termios.c_cc[VMIN] = blocksz;
  termios.c_cc[VTIME] = 2;

#if (B4800 != 4800)
/* Not every system has speed settings equal to absolute speed value. */

  switch (baud)
  {
  case 300:
    baud = B300;
    break;
  case 1200:
    baud = B1200;
    break;
  case 2400:
    baud = B2400;
    break;
  case 4800:
    baud = B4800;
    break;
  case 9600:
    baud = B9600;
    break;
  case 19200:
    baud = B19200;
    break;
  case 38400:
    baud = B38400;
    break;
#ifdef B57600
  case 57600:
    baud = B57600;
    break;
#endif
#ifdef B115200
  case 115200:
    baud = B115200;
    break;
#endif
#ifdef B230400
  case 230400:
    baud = B230400;
    break;
#endif
  default:
    fprintf(stderr, "WARNING: Baud settings not useful, using 19200\n");
    baud = B19200;
    break;
  }
#endif

  if(cfsetispeed(&termios, baud) != 0)
  {
    perror("ERROR: setting serial speed with cfsetispeed");
    return (-1);
  }
  if(cfsetospeed(&termios, baud) != 0)
  {
    perror("ERROR: setting serial speed with cfsetospeed");
    return (-1);
  }
  if(tcsetattr(fd, TCSANOW, &termios) < 0)
  {
    perror("ERROR: setting serial attributes");
    return (-1);
  }
  if(fcntl(fd, F_SETFL, 0) == -1)
  {
    perror("WARNING: setting blocking inputmode failed");
  }
  return (fd);
} /* openserial */

/********************************************************************
* usage
*
* Send a usage message to standard error and quit the program.
*
* Parameters:
*     None.
*
* Return Value:
*     The function does not return a value.
*
* Remarks:
*
*********************************************************************/
static
#ifdef __GNUC__
__attribute__ ((noreturn))
#endif /* __GNUC__ */
void usage(int rc, char *name)
{
  fprintf(stderr, "Version %s (%s) GPL" COMPILEDATE "\nUsage:\n%s [OPTIONS]\n",
    revisionstr, datestr, name);
  fprintf(stderr, "PURPOSE\n");
  fprintf(stderr, "   The purpose of this program is to pick up a GNSS data stream (Input, Source)\n");
  fprintf(stderr, "   from either\n\n");
  fprintf(stderr, "     1. a Serial port, or\n");
  fprintf(stderr, "     2. an IP server, or\n");
  fprintf(stderr, "     3. a File, or\n");
  fprintf(stderr, "     4. a SISNeT Data Server, or\n");
  fprintf(stderr, "     5. a UDP server, or\n");
  fprintf(stderr, "     6. an NTRIP Version 1.0 Caster\n\n");
  fprintf(stderr, "   and forward that incoming stream (Output, Destination) to either\n\n");
  fprintf(stderr, "     - an NTRIP Version 1.0 Caster, or\n");
  fprintf(stderr, "     - an NTRIP Version 2.0 Caster via TCP/IP or RTSP/RTP.\n\n\n");
  fprintf(stderr, "OPTIONS\n");
  fprintf(stderr, "   -h|? print this help screen\n\n");
  fprintf(stderr, "    -E <ProxyHost>       Proxy server host name or address, required i.e. when\n");
  fprintf(stderr, "                         running the program in a proxy server protected LAN,\n");
  fprintf(stderr, "                         optional\n");
  fprintf(stderr, "    -F <ProxyPort>       Proxy server IP port, required i.e. when running\n");
  fprintf(stderr, "                         the program in a proxy server protected LAN, optional\n");
  fprintf(stderr, "    -R <maxDelay>        Reconnect mechanism with maximum delay between reconnect\n");
  fprintf(stderr, "                         attemts in seconds, default: no reconnect activated,\n");
  fprintf(stderr, "                         optional\n\n");
  fprintf(stderr, "    -M <InputMode> Sets the input mode (1 = Serial Port, 2 = IP server,\n");
  fprintf(stderr, "       3 = File, 4 = SISNeT Data Server, 5 = UDP server, 6 = NTRIP Caster),\n");
  fprintf(stderr, "       mandatory\n\n");
  fprintf(stderr, "       <InputMode> = 1 (Serial Port):\n");
  fprintf(stderr, "       -i <Device>       Serial input device, default: /dev/gps, mandatory if\n");
  fprintf(stderr, "                         <InputMode>=1\n");
  fprintf(stderr, "       -b <BaudRate>     Serial input baud rate, default: 19200 bps, mandatory\n");
  fprintf(stderr, "                         if <InputMode>=1\n\n");
  fprintf(stderr, "       <InputMode> = 2|5 (IP port | UDP port):\n");
  fprintf(stderr, "       -H <ServerHost>   Input host name or address, default: 127.0.0.1,\n");
  fprintf(stderr, "                         mandatory if <InputMode> = 2|5\n");
  fprintf(stderr, "       -P <ServerPort>   Input port, default: 1025, mandatory if <InputMode>= 2|5\n");
  fprintf(stderr, "       -f <ServerFile>   Name of initialization file to be send to server,\n");
  fprintf(stderr, "                         optional\n");
  fprintf(stderr, "       -x <ServerUser>   User ID to access incoming stream, optional\n");
  fprintf(stderr, "       -y <ServerPass>   Password, to access incoming stream, optional\n");
  fprintf(stderr, "       -B Bind to incoming UDP stream, optional for <InputMode> = 5\n\n");
  fprintf(stderr, "       <InputMode> = 3 (File):\n");
  fprintf(stderr, "       -s <File>         File name to simulate stream by reading data from (log)\n");
  fprintf(stderr, "                         file, default is /dev/stdin, mandatory for <InputMode> = 3\n\n");
  fprintf(stderr, "       <InputMode> = 4 (SISNeT Data Server):\n");
  fprintf(stderr, "       -H <SisnetHost>   SISNeT Data Server name or address,\n");
  fprintf(stderr, "                         default: 131.176.49.142, mandatory if <InputMode> = 4\n");
  fprintf(stderr, "       -P <SisnetPort>   SISNeT Data Server port, default: 7777, mandatory if\n");
  fprintf(stderr, "                         <InputMode> = 4\n");
  fprintf(stderr, "       -u <SisnetUser>   SISNeT Data Server user ID, mandatory if <InputMode> = 4\n");
  fprintf(stderr, "       -l <SisnetPass>   SISNeT Data Server password, mandatory if <InputMode> = 4\n");
  fprintf(stderr, "       -V <SisnetVers>   SISNeT Data Server Version number, options are 2.1, 3.0\n");
  fprintf(stderr, "                         or 3.1, default: 3.1, mandatory if <InputMode> = 4\n\n");
  fprintf(stderr, "       <InputMode> = 6 (NTRIP Version 1.0 Caster):\n");
  fprintf(stderr, "       -H <SourceHost>   Source caster name or address, default: 127.0.0.1,\n");
  fprintf(stderr, "                         mandatory if <InputMode> = 6\n");
  fprintf(stderr, "       -P <SourcePort>   Source caster port, default: 2101, mandatory if\n");
  fprintf(stderr, "                         <InputMode> = 6\n");
  fprintf(stderr, "       -D <SourceMount>  Source caster mountpoint for stream input, mandatory if\n");
  fprintf(stderr, "                         <InputMode> = 6\n");
  fprintf(stderr, "       -U <SourceUser>   Source caster user Id for input stream access, mandatory\n");
  fprintf(stderr, "                         for protected streams if <InputMode> = 6\n");
  fprintf(stderr, "       -W <SourcePass>   Source caster password for input stream access, mandatory\n");
  fprintf(stderr, "                         for protected streams if <InputMode> = 6\n\n");
  fprintf(stderr, "    -O <OutputMode> Sets output mode for communatation with destination caster\n");
  fprintf(stderr, "       1 = http: NTRIP Version 2.0 Caster in TCP/IP mode\n");
  fprintf(stderr, "       2 = rtsp: NTRIP Version 2.0 Caster in RTSP/RTP mode\n");
  fprintf(stderr, "       3 = ntrip1: NTRIP Version 1.0 Caster\n");
  fprintf(stderr, "       optional\n\n");
  fprintf(stderr, "       Defaults to NTRIP1.0, but will change to 2.0 in future versions\n");
  fprintf(stderr, "       Note that the program automatically falls back from mode rtsp to mode http and\n");
  fprintf(stderr, "       further to mode ntrip1 if necessary.\n\n");
  fprintf(stderr, "       -a <DestHost>     Destination caster name or address, default: 127.0.0.1,\n");
  fprintf(stderr, "                         mandatory\n");
  fprintf(stderr, "       -p <DestPort>     Destination caster port, default: 2101, mandatory\n");
  fprintf(stderr, "       -m <DestMount>    Destination caster mountpoint for stream upload,\n");
  fprintf(stderr, "                         mandatory\n");
  fprintf(stderr, "       -n <DestUser>     Destination caster user ID for stream upload to\n");
  fprintf(stderr, "                         mountpoint, only for NTRIP Version 2.0 destination\n");
  fprintf(stderr, "                         casters, mandatory\n");
  fprintf(stderr, "       -c <DestPass>     Destination caster password for stream upload to\n");
  fprintf(stderr, "                         mountpoint, mandatory\n");
  fprintf(stderr, "       -N <STR-record>   Sourcetable STR-record\n");
  fprintf(stderr, "                         optional for NTRIP Version 2.0 in RTSP/RTP and TCP/IP mode\n\n");
  exit(rc);
} /* usage */


/********************************************************************/
/* signal handling                                                  */
/********************************************************************/
#ifdef __GNUC__
static void handle_sigint(int sig __attribute__((__unused__)))
#else /* __GNUC__ */
static void handle_sigint(int sig)
#endif /* __GNUC__ */
{
  sigint_received  = 1;
  fprintf(stderr, "WARNING: SIGINT received - ntripserver terminates\n");
}

#ifdef __GNUC__
static void handle_alarm(int sig __attribute__((__unused__)))
#else /* __GNUC__ */
static void handle_alarm(int sig)
#endif /* __GNUC__ */
{
  sigalarm_received = 1;
  fprintf(stderr, "ERROR: more than %d seconds no activity\n", ALARMTIME);
}

#ifdef __GNUC__
static void handle_sigpipe(int sig __attribute__((__unused__)))
#else /* __GNUC__ */
static void handle_sigpipe(int sig)
#endif /* __GNUC__ */
{sigpipe_received = 1;}

static void setup_signal_handler(int sig, void (*handler)(int))
{
#if _POSIX_VERSION > 198800L
  struct sigaction action;

  action.sa_handler = handler;
  sigemptyset(&(action.sa_mask));
  sigaddset(&(action.sa_mask), sig);
  action.sa_flags = 0;
  sigaction(sig, &action, 0);
#else
  signal(sig, handler);
#endif
  return;
} /* setupsignal_handler */

/********************************************************************
 * base64-encoding                                                  *
*******************************************************************/
static const char encodingTable [64] =
{
  'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P',
  'Q','R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f',
  'g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v',
  'w','x','y','z','0','1','2','3','4','5','6','7','8','9','+','/'
};

/* does not buffer overrun, but breaks directly after an error */
/* returns the number of required bytes */
static int encode(char *buf, int size, const char *user, const char *pwd)
{
  unsigned char inbuf[3];
  char *out = buf;
  int i, sep = 0, fill = 0, bytes = 0;

  while(*user || *pwd)
  {
    i = 0;
    while(i < 3 && *user) inbuf[i++] = *(user++);
    if(i < 3 && !sep)    {inbuf[i++] = ':'; ++sep; }
    while(i < 3 && *pwd)  inbuf[i++] = *(pwd++);
    while(i < 3)         {inbuf[i++] = 0; ++fill; }
    if(out-buf < size-1)
      *(out++) = encodingTable[(inbuf [0] & 0xFC) >> 2];
    if(out-buf < size-1)
      *(out++) = encodingTable[((inbuf [0] & 0x03) << 4)
               | ((inbuf [1] & 0xF0) >> 4)];
    if(out-buf < size-1)
    {
      if(fill == 2)
        *(out++) = '=';
      else
        *(out++) = encodingTable[((inbuf [1] & 0x0F) << 2)
                 | ((inbuf [2] & 0xC0) >> 6)];
    }
    if(out-buf < size-1)
    {
      if(fill >= 1)
        *(out++) = '=';
      else
        *(out++) = encodingTable[inbuf [2] & 0x3F];
    }
    bytes += 4;
  }
  if(out-buf < size)
    *out = 0;
  return bytes;
}/* base64 Encoding */


/********************************************************************
 * send message to caster                                           *
*********************************************************************/
static int send_to_caster(char *input, int socket, int input_size)
{
 int send_error = 1;

  if((send(socket, input, (size_t)input_size, 0)) != input_size)
  {
    fprintf(stderr, "WARNING: could not send full header to Destination caster\n");
    send_error = 0;
  }
#ifndef NDEBUG
  else
  {
    fprintf(stderr, "\nDestination caster request:\n");
    fprintf(stderr, "%s", input);
  }
#endif
  return send_error;
}/* send_to_caster */


/********************************************************************
 * reconnect                                                        *
*********************************************************************/
int reconnect(int rec_sec, int rec_sec_max)
{
  fprintf(stderr,"reconnect in <%d> seconds\n\n", rec_sec);
  rec_sec *= 2;
  if (rec_sec > rec_sec_max) rec_sec = rec_sec_max;
  sleep(rec_sec);
  sigalarm_received = 0;
  sigpipe_received = 0;
  return rec_sec;
} /* reconnect */


/********************************************************************
 * close session                                                    *
*********************************************************************/
static void close_session(const char *caster_addr, const char *mountpoint, 
int cseq, int session, char *rtsp_ext, int fallback)
{
  int  size_send_buf;
  char send_buf[BUFSZ];

  if((gpsfd != -1) && (!fallback))
  {
    if(close(gpsfd) == -1)
    {
      perror("ERROR: close input device ");
      exit(0);
    }
    else
    {
      gpsfd = -1;
#ifndef NDEBUG  
    fprintf(stderr, "close input device: successful\n");
#endif
    }
  }

  if(socket_udp  != -1)
  {
    if(cseq == 2)
    {
      size_send_buf = snprintf(send_buf, sizeof(send_buf),
        "TEARDOWN rtsp://%s%s/%s RTSP/1.0\r\n"
        "CSeq: 2\r\n"
        "Session: %d\r\n"
        "\r\n",
        caster_addr, rtsp_ext, mountpoint, session);
      if((size_send_buf >= (int)sizeof(send_buf)) || (size_send_buf < 0))
      {
        fprintf(stderr, "ERROR: Destination caster request to long\n");
        exit(0);
      }
      send_to_caster(send_buf, socket_tcp, size_send_buf); strcpy(send_buf,"");
      size_send_buf = recv(socket_tcp, send_buf, sizeof(send_buf), 0);
      send_buf[size_send_buf] = '\0';
#ifndef NDEBUG
      fprintf(stderr, "Destination caster response:\n%s", send_buf);
#endif
    }
    if(close(socket_udp)==-1)
    {
      perror("ERROR: close udp socket");
      exit(0);
    }
    else
    {
      socket_udp = -1;
#ifndef NDEBUG
      fprintf(stderr, "close udp socket: successful\n");
#endif
    }
  }

  if(socket_tcp != -1)
  {
    if(close(socket_tcp) == -1)
    {
      perror("ERROR: close tcp socket");
      exit(0);
    }
    else
    {
      socket_tcp = -1;
#ifndef NDEBUG
      fprintf(stderr, "close tcp socket: successful\n");
#endif
    }
  }
} /* close_session */