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—sdk:gps-udp-broadcast [2017/10/11 16:34] (current) – created fachet
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 +====== SDK Script gps-udp-broadcast.are ======
 +<code c gps-udp-broadcast.are>
 + /* DESC: This script sends the local GPS NMEA via UDP broadcast to multiple ports 
 +  * selected by NMEA type.
 +  * Copyright (C) 2017 NetModule AG, Switzerland
 +  */
 +BroadcastIP = "192.168.1.255";
 +
 +// Connect to GPS Deamon
 +int connect_gpsd() {
 +    nb_syslog("Connecting to GPS daemon.");
 +    sock = -1;
 +    while(true)
 +    {
 +        sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
 +        if (sock < 0)
 +        {
 +            nb_syslog("Unable to open TCP socket. Retrying in 5 seconds");
 +            sleep(5);
 +            continue;
 +        }
 +
 +        if (connect(sock, "127.0.0.1", 2947) < 0)
 +        {
 +            nb_syslog("Could not connect to GPS daemon. Retrying in 5 seconds");
 +            close(sock);
 +            sleep(5);
 +            continue;
 +        }
 +        nb_syslog("GPS daemon connected.");
 +        return(sock);
 +        break;
 +    }
 +}
 +
 +     
 +
 +gpsd = connect_gpsd();
 +
 +/* open UDP server socket */
 +server = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
 +if (server < 0) {
 +   nb_syslog("Unable to open server socket.");
 +   close(gpsd);
 +   exit(-1);
 +}
 +setsockopt(server, SOL_SOCKET, SO_BROADCAST, 1);
 +
 +nb_syslog("GPS Broadcast to %s", BroadcastIP);
 +// process NMEA stream 
 +   
 +nb_syslog("Processing NMEA data");
 + 
 +while (true) {
 +   /* wait for socket data  */
 +   rv = select(gpsd, 3);
 +   if (rv > 0) {
 +      data = recv(gpsd);
 +      len = strlen(data);
 +   } else if (rv < 0) {
 +      nb_syslog("select failed");
 +      len = -1;
 +   } else { // nothing received
 +      continue;
 +   } 
 +   if (len <= 0) {
 +      nb_syslog("Receive failed, re-connecting to GPS daemon");
 +      close(gpsd);
 +      gpsd = connect_gpsd();
 +      if (gpsd < 0)
 +         exit(-2);
 +   } else {
 +      // printf("got >>>%s<<<\n", data);
 +      while(true)   //handle CR /LF problems and separate data into singel $Gxxx frames
 +         {
 +            newlinepos = strstr(data, "\r\n");
 +            seplen = 0;
 +            if (newlinepos != ()) {
 +               seplen = 2;
 +            } else {
 +               newlinepos = strstr(data, "\n");
 +               if (newlinepos != ()) {
 +                  seplen = 1;
 +               }
 +            }
 +            
 +            if (seplen != 0) {
 +               frame = strcat(left(data, newlinepos), "\r\n");
 +               // printf("frame >>>%s<<<\n", frame);
 +               if (left(frame, 6) == "$GPRMC") {
 +                  sendto(server, frame, BroadcastIP, 5125);
 +                  sendto(server, frame, BroadcastIP, 5126);
 +                  sendto(server, frame, BroadcastIP, 6060);
 +               }
 +               if (left(frame, 6) == "$GPGGA") {
 +                  sendto(server, frame, BroadcastIP, 5126);
 +               }
 +               if (left(frame, 6) == "$GPGSA") {
 +                  sendto(server, frame, BroadcastIP, 5126);
 +               }      
 +               data = substr(data, newlinepos + seplen);
 +            }
 +            else
 +               break;
 +            
 +        }   
 +   }
 +}
 +exit(-3);
 +</code>
  

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sdk/gps-udp-broadcast.txt · Last modified: 2017/10/11 16:34 by fachet