From 57e9bdeae2f00664616ee1d9a936a5cfe27bfd30 Mon Sep 17 00:00:00 2001
From: "Fulup.ArFoll" <fulup@sinagot.net>
Date: Tue, 30 Apr 2013 23:24:47 +0200
Subject: Added gps2udp a gpsdclient to dispatch AIS to AISHUB, MarineTraffic,
 ...

Signed-off-by: Eric S. Raymond <esr@thyrsus.com>
---
 gps2udp.c | 448 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 448 insertions(+)
 create mode 100644 gps2udp.c

(limited to 'gps2udp.c')

diff --git a/gps2udp.c b/gps2udp.c
new file mode 100644
index 00000000..271ee2ac
--- /dev/null
+++ b/gps2udp.c
@@ -0,0 +1,448 @@
+/*
+ * gps2udp
+ *
+ * Dump NMEA to UDP socket for AIShub 
+ *      gps2udp -u data.aishub.net:1234
+ *
+ * Author Fulup Ar Foll (directly inspired from gpspipe.c from gpsd official distrib)
+ * Date   01-march-2013
+ *
+ * This file is Copyright (c) 2010 by the GPSD project
+ * BSD terms apply: see the file COPYING in the distribution root for details.
+ *
+ */
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <errno.h>
+#include <string.h>
+#include <strings.h>
+#include <fcntl.h>
+#include <termios.h>
+#include <time.h>
+#include <sys/time.h>
+
+#ifndef S_SPLINT_S
+#include <unistd.h>
+#endif /* S_SPLINT_S */
+
+#include "gpsd.h"
+#include "gpsdclient.h"
+#include "revision.h"
+
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+
+
+static struct gps_data_t gpsdata;
+
+/* UDP socket variables */
+#define MAX_UDP_DEST 5
+static struct sockaddr_in remote[MAX_UDP_DEST];
+static int sock[MAX_UDP_DEST];
+static int udpchanel;
+
+/* gpsclient source */
+#define MAX_GPSD_RETRY 10
+static struct fixsource_t gpsd_source;
+static int flags;
+static int debug=0;
+static int aisonly=0;
+
+// return local time hh:mm:ss
+static char* time2string (void)  {
+   #define MAX_TIME_LEN 80
+   static char buffer[MAX_TIME_LEN];
+   time_t curtime;
+   struct tm *loctime;
+     
+   /* Get the current time. */
+   curtime = time (NULL);
+     
+   /* Convert it to local time representation. */
+   loctime = localtime (&curtime);
+     
+     
+   /* Print it out in a nice format. */
+   strftime (buffer, MAX_TIME_LEN, "%H:%M:%S", loctime);
+     
+return (buffer);
+}
+
+static int send_udp (char *nmeastring, int ind) {
+   char message [255];
+   char *buffer;
+   int  status, chanel;
+
+   /* if string lenght is unknow make a copy and compute it */
+   if (ind == 0) {
+     /* compute message size and add 0x0a 0x0d */
+     for (ind=0; nmeastring [ind] != '\0'; ind ++) {
+        if (ind > (int)sizeof (message)) {
+          fprintf(stderr, "gps2udp: too big [%s] \n", nmeastring);
+          return -1;
+        }
+        message[ind] = nmeastring[ind];
+     }
+     buffer = message;
+   } else {
+     /* use directly nmeastring but change terminition */
+     buffer = nmeastring;
+     ind=ind-1;
+   }
+   /* Add termination to NMEA feed for AISHUB */
+   buffer[ind]='\n'; ind ++;
+   buffer[ind]='\r'; ind ++;
+   buffer[ind]='\0';
+
+   /* send message on udp chanel */   
+   for (chanel=0; chanel < udpchanel; chanel ++) {
+     status=sendto(sock[chanel],buffer,ind,0,&remote[chanel],sizeof(remote));
+     if (status < ind) {
+       fprintf(stderr, "gps2udp: fail to send [%s] \n", nmeastring);
+       return -1;
+     }
+   }
+return 0;
+}
+
+
+static int open_udp(char **hostport)
+/* Open and bind udp socket to host */
+{
+   struct hostent *hp;
+   char *hostname = NULL;
+   char *portname = NULL;
+   int  portnum, chanel;
+
+   for (chanel=0; chanel <udpchanel; chanel ++) {
+
+   /* parse argement */
+     hostname = strsep(&hostport[chanel], ":");
+     portname = strsep(&hostport[chanel], ":");
+     if ((hostname == NULL) || (portname == NULL)) {
+       fprintf(stderr, "gps2udp: syntaxe is [-u hostname:port]\n");
+       return (-1);
+     }
+
+     portnum= strtol (portname,NULL,0);
+     if (errno != 0) {
+       fprintf(stderr, "gps2udp: syntaxe is [-u hostname:port] [%s] is not a valid port number\n",portname);
+       return (-1);
+     }
+
+     sock[chanel]= socket(AF_INET, SOCK_DGRAM, 0);
+     if (sock[chanel] < 0) {
+        fprintf(stderr, "gps2udp: error creating UDP socket\n");
+        return (-1);
+     }
+
+     remote[chanel].sin_family = AF_INET;
+     hp = gethostbyname(hostname);
+     if (hp==NULL) {
+       fprintf(stderr, "gps2udp: syntaxe is [-u hostname:port] [%s] is not a valid hostnamer\n",hostname);
+       return (-1);
+     }
+
+     bcopy((char *)hp->h_addr, (char *)&remote[chanel].sin_addr, hp->h_length);
+     remote[chanel].sin_port = htons(portnum);
+   }
+return (0);
+}
+
+static void usage(void)
+{
+    (void)fprintf(stderr,
+		  "Usage: gps2udp [OPTIONS] [server[:port[:device]]]\n\n"
+		  "-h Show this help.\n" 
+                  "-u Send UDP NMEA/JASON feed to host:port [multiple -u host:port accepted\n"
+		  "-n Feed NMEA.\n"
+		  "-j Feed Jason.\n"
+		  "-a Select !AISDM message only.\n"
+		  "-c [count] exit after count packets.\n"
+		  "-b Run in background as a daemon.\n" 
+		  "-d [0-2] 1 display sent packets, 2 ignored packets.\n" 
+		  "-v Print version and exit.\n\n"
+		  "You must specify one, or more, of -r, -R, or -w\n"
+		  );
+}
+
+/* loop until we connect with GPSd */
+static void connect2gpsd (int restart) {
+    int delay,status;
+
+    if (restart) {
+     gps_close   (&gpsdata);
+     if (debug > 0)  fprintf(stdout, "gps2udp [%s] reset gpsd connection\n", time2string());
+
+    }
+
+    /* loop until we reach GPSd */
+    for (delay=10;;delay=delay*2) {
+        status = gps_open(gpsd_source.server, gpsd_source.port, &gpsdata);
+        if (status != 0) {
+	   fprintf(stderr, "gps2udp [%s] connection failed at %s:%s\n",
+	      time2string(), gpsd_source.server, gpsd_source.port);
+           sleep (delay);
+        } else {
+          if (debug > 0)  fprintf(stdout, "gps2udp [%s] connect to gpsd %s:%s\n",
+             time2string(), gpsd_source.server, gpsd_source.port);
+          break;
+        }
+    }
+    /* select the right set of gps data */
+    gps_stream(&gpsdata, flags, gpsd_source.device);
+    
+}
+
+/* get date from gpsd */
+static int read_gpsd (char *message, int len) {
+   
+   struct timeval tv;
+   fd_set fds,master;
+   int result,ind;
+   char c;
+   int retry=0;
+
+    // prepare select structure */
+    FD_ZERO(&master);
+    FD_SET(gpsdata.gps_fd, &master);
+
+
+   /* loop until we get some data or an error */
+   for (ind=0; ind<len;) {
+
+        /* prepare for a blocking read with a 10s timeout */
+        tv.tv_sec =  10;
+        tv.tv_usec = 0;
+        memcpy(&fds,&master,sizeof(fd_set));
+        result = select(gpsdata.gps_fd+1, &fds, NULL, NULL, &tv);
+      
+        switch (result) {
+        case 1: /* we have data waiting let's process them */
+
+           result = (int)read(gpsdata.gps_fd, &c, 1);
+
+           /* If we lost gpsd connection reset it */
+           if (result != 1) {
+              connect2gpsd (true);
+           }
+            
+           if ((c == '\n') || (c == '\r')){
+               message[ind]='\0';
+
+               if (ind > 0) {
+                 if (retry > 0) {
+                     if (debug ==1) fprintf (stdout,"\r");
+                     if (debug > 1) fprintf (stdout," [%s] No Data for: %ds\n",time2string(), retry*10);
+                 }
+
+                 if (aisonly && message[0] != '!') {
+                    if (debug >1) fprintf (stdout,".... [%s %d] %s\n", time2string(), ind, message);
+                    return (0);
+                 }
+               }
+                     
+               return (ind+1);
+           } else {
+              message[ind]= c;
+              ind ++;
+           }
+           break;
+
+        case 0: /* no data fail in timeout */
+           retry ++;
+           /* if too many empty packet are received reset gpsd connection */
+           if (retry > MAX_GPSD_RETRY)  {
+              connect2gpsd (true);
+              retry=0;
+           }
+           if (debug > 0) (void)write (1,".",1);
+
+           break;
+
+        default:/* we lost connection with gpsd */
+           connect2gpsd (true);
+           break;
+        }
+   }
+   message [ind]='\0';
+   fprintf (stderr,"\n gps2udp: message to big [%s]\n", message);
+   return (-1);
+}
+
+// 6 bits decoding of AIS payload
+static unsigned char AISto6bit(char c) {
+    if(c < 0x30)
+        return (unsigned char)-1;
+    if(c > 0x77)
+        return (unsigned char)-1;
+    if((0x57 < c) && (c < 0x60))
+        return (unsigned char)-1;
+
+    unsigned char cp = c;
+    cp += 0x28;
+
+    if(cp > 0x80)
+        cp += 0x20;
+    else
+        cp += 0x28;
+    return (unsigned char)(cp & 0x3f);
+}
+
+// get mmsi from ais bit string
+static int AISGetInt(unsigned char* bitbytes, int sp, int len) {
+    int acc = 0;
+    int s0p = sp-1;                          // to zero base
+    int cp, cx, c0, i, cs;
+
+    for(i=0 ; i<len ; i++)
+    {
+        acc  = acc << 1;
+        cp = (s0p + i) / 6;
+        cx = (int)bitbytes[cp];              // what if cp >= byte_length?
+        cs = 5 - ((s0p + i) % 6);
+        c0 = (cx >> (5 - ((s0p + i) % 6))) & 1;
+        acc |= c0;
+    }
+
+    return acc;
+
+}
+
+
+int main(int argc, char **argv) {
+    bool daemonize = false;
+    long count = -1;
+    int option, status;
+    char *udphostport[MAX_UDP_DEST];
+
+    flags = WATCH_ENABLE;
+    while ((option = getopt(argc, argv, "?habnjcvl:u:d:")) != -1) {
+
+	switch (option) {
+	case 'd':
+            debug= strtol(optarg, 0, 0);
+	    break;
+	case 'n':
+            if (debug >0) fprintf (stdout, "NMEA selected\n");
+	    flags |= WATCH_NMEA;
+	    break;
+	case 'j':
+            if (debug >0) fprintf (stdout, "JASON selected\n");
+	    flags |= WATCH_JSON;
+	    break;
+	case 'a':
+            aisonly=1;
+	    break;
+	case 'c':
+	    count = strtol(optarg, 0, 0);
+	    break;
+	case 'b':
+	    daemonize = true;
+	    break;
+        case 'u':
+            if (udpchanel > MAX_UDP_DEST) {
+               fprintf (stderr, "gps2udp: to many UDP destination (max=%d)\n",MAX_UDP_DEST);
+            } else {
+               udphostport [udpchanel]= optarg;
+               udpchanel ++;
+            }
+            break;
+	case 'v':
+	    (void)fprintf(stderr, "%s: %s (revision %s)\n",
+			  argv[0], VERSION, REVISION);
+	    exit(0);
+	case '?':
+	case 'h':
+	default:
+	    usage();
+	    exit(1);
+	}
+    }
+
+    /* Grok the server, port, and device. */
+    if (optind < argc) gpsd_source_spec(argv[optind], &gpsd_source);
+    else gpsd_source_spec(NULL, &gpsd_source);
+    if (gpsd_source.device != NULL) flags |= WATCH_DEVICE;
+
+    /* check before going background if we can connect to gpsd */
+    connect2gpsd (false);
+
+    /* Open UDP port */
+    if (udpchanel > 0) {
+        status = open_udp(udphostport);
+	if (status !=0) exit (1);
+    }
+
+    /* Daemonize if the user requested it. */
+    if (daemonize) {
+	if (daemon(0, 0) != 0) {
+	    fprintf(stderr, "gps2udp: demonization failed: %s\n", strerror(errno));
+        }
+    }
+
+    /* Infinit loop to get date from GPSd and push them to AIShub */
+    for (;;) {
+
+       char buffer [512];
+       int  len;
+
+       len = read_gpsd (buffer, sizeof (buffer));
+ 
+       /* ignore empty message */
+       if (len > 3) {
+         if (debug > 0) {
+               fprintf (stdout,"---> [%s] -- %s",time2string(),buffer);
+
+               // Try to extract MMSI from AIS payload
+               if (strncmp (buffer,"!AIVDM",6) == 0) {
+                  #define MAX_INFO 6
+                  char packet [512];
+                  char *adrpkt=packet;
+                  char *info  [MAX_INFO];
+                  int  i,j;
+                  unsigned int  mmsi;
+                  unsigned char bitstrings [255];
+
+                  // strtok break original string
+                  strncpy (packet,buffer,sizeof(packet));
+                  for (j=0; j<MAX_INFO; j++) {
+                     info [j] = strsep (&adrpkt, ",");
+                  }
+
+                  for(i=0 ; i<(int)strlen(info[5]); i++)  {
+                      if (i > (int) sizeof (bitstrings)) break;
+                      bitstrings[i] = AISto6bit(info[5][i]);
+                  }
+
+                 mmsi=AISGetInt (bitstrings, 9, 30); 
+                 fprintf (stdout," MMSI=%9d", mmsi);
+
+               } 
+               fprintf (stdout,"\n");
+
+         }
+
+         // send to all UDP destination
+         if (udpchanel > 0) send_udp (buffer, len);
+
+         // if we count messages check it now
+         if (count >= 0) {
+   	    if (count-- == 0) {
+	      /* completed count */
+              fprintf (stderr, "gpsd2udp normal exit after [%d] packets\n",(int)count);
+	      exit (0); 
+	    }
+         }  // end count  
+        } // end len > 3
+     } // end for (;;)
+ 
+// This is an infinite loop, should never be here
+fprintf (stderr, "gpsd2udp ERROR abnormal exit\n");
+exit (-1);
+}
-- 
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