create a net_ namespace for gpsd-as-a-client protocols. currently these are

dgpsip and ntrip. eventually, gpsd will be able to connect to a remote gpsd.

1 files changed, 149 insertions, 0 deletions

diff --git a/net_dgpsip.c b/net_dgpsip.c
new file mode 100644
index 00000000..15962dd5
--- /dev/null
+++ b/net_dgpsip.c
@@ -0,0 +1,149 @@
+/* $Id$ */
+/* dgpsip.c -- gather and dispatch DGPS data from DGPSIP servers */
+#include <sys/types.h>
+#ifndef S_SPLINT_S
+#include <sys/socket.h>
+#endif /* S_SPLINT_S */
+#include <sys/time.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <math.h>
+#include <netdb.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include "gpsd_config.h"
+#include "gpsd.h"
+
+/*@ -branchstate */
+int dgpsip_open(struct gps_context_t *context, const char *dgpsserver)
+/* open a connection to a DGPSIP server */
+{
+    char hn[256], buf[BUFSIZ];
+    char *colon, *dgpsport = "rtcm-sc104";
+    int opts;
+
+    if ((colon = strchr(dgpsserver, ':')) != NULL) {
+	dgpsport = colon+1;
+	*colon = '\0';
+    }
+    if (!getservbyname(dgpsport, "tcp"))
+	dgpsport = DEFAULT_RTCM_PORT;
+
+    context->dsock = netlib_connectsock(dgpsserver, dgpsport, "tcp");
+    if (context->dsock >= 0) {
+	gpsd_report(LOG_PROG,"connection to DGPS server %s established.\n",dgpsserver);
+	(void)gethostname(hn, sizeof(hn));
+	/* greeting required by some RTCM104 servers; others will ignore it */
+	(void)snprintf(buf,sizeof(buf), "HELO %s gpsd %s\r\nR\r\n",hn,VERSION);
+	if (write(context->dsock, buf, strlen(buf)) == (ssize_t)strlen(buf))
+	    context->dgnss_service = dgnss_dgpsip;
+	else
+	    gpsd_report(LOG_ERROR, "hello to DGPS server %s failed\n", dgpsserver);
+    } else
+	gpsd_report(LOG_ERROR, "can't connect to DGPS server %s, netlib error %d.\n", dgpsserver, context->dsock);
+    opts = fcntl(context->dsock, F_GETFL);
+
+    if (opts >= 0)
+	(void)fcntl(context->dsock, F_SETFL, opts | O_NONBLOCK);
+    return context->dsock;
+}
+/*@ +branchstate */
+
+void dgpsip_report(struct gps_device_t *session)
+/* may be time to ship a usage report to the DGPSIP server */
+{
+    /*
+     * 10 is an arbitrary number, the point is to have gotten several good
+     * fixes before reporting usage to our DGPSIP server.
+     */
+    if (session->context->fixcnt > 10 && !session->context->sentdgps) {
+	session->context->sentdgps = true;
+	if (session->context->dsock > -1) {
+	    char buf[BUFSIZ];
+	    (void)snprintf(buf, sizeof(buf), "R %0.8f %0.8f %0.2f\r\n", 
+			   session->gpsdata.fix.latitude, 
+			   session->gpsdata.fix.longitude, 
+			   session->gpsdata.fix.altitude);
+	    if (write(session->context->dsock, buf, strlen(buf)) == (ssize_t)strlen(buf))
+		gpsd_report(LOG_IO, "=> dgps %s", buf);
+	    else
+		gpsd_report(LOG_IO, "write to dgps FAILED");
+	}
+    }
+}
+
+#define DGPS_THRESHOLD	1600000	/* max. useful dist. from DGPS server (m) */
+#define SERVER_SAMPLE	12	/* # of servers within threshold to check */
+
+struct dgps_server_t {
+    double lat, lon;
+    char server[257];
+    double dist;
+};
+
+static int srvcmp(const void *s, const void *t)
+{
+    return (int)(((const struct dgps_server_t *)s)->dist - ((const struct dgps_server_t *)t)->dist); /* fixes: warning: cast discards qualifiers from pointer target type */
+}
+
+void dgpsip_autoconnect(struct gps_context_t *context,
+			double lat, double lon,
+			const char *serverlist)
+/* tell the library to talk to the nearest DGPSIP server */
+{
+    struct dgps_server_t keep[SERVER_SAMPLE], hold, *sp, *tp;
+    char buf[BUFSIZ];
+    FILE *sfp = fopen(serverlist, "r");
+
+    if (sfp == NULL) {
+	gpsd_report(LOG_ERROR, "no DGPS server list found.\n");
+	context->dsock = -2;	/* don't try this again */
+	return;
+    }
+
+    for (sp = keep; sp < keep + SERVER_SAMPLE; sp++) {
+	sp->dist = DGPS_THRESHOLD;
+	sp->server[0] = '\0';
+    }
+    /*@ -usedef @*/
+    while (fgets(buf, (int)sizeof(buf), sfp)) {
+	char *cp = strchr(buf, '#');
+	if (cp != NULL)
+	    *cp = '\0';
+	if (sscanf(buf,"%lf %lf %256s",&hold.lat, &hold.lon, hold.server)==3) {
+	    hold.dist = earth_distance(lat, lon, hold.lat, hold.lon);
+	    tp = NULL;
+	    /*
+	     * The idea here is to look for a server in the sample array
+	     * that is (a) closer than the one we're checking, and (b)
+	     * furtherest away of all those that are closer.  Replace it.
+	     * In this way we end up with the closest possible set.
+	     */
+	    for (sp = keep; sp < keep + SERVER_SAMPLE; sp++)
+		if (hold.dist < sp->dist && (tp==NULL || hold.dist > tp->dist))
+		    tp = sp;
+	    if (tp != NULL)
+		memcpy(tp, &hold, sizeof(struct dgps_server_t));
+	}
+    }
+    (void)fclose(sfp);
+
+    if (keep[0].server[0] == '\0') {
+	gpsd_report(LOG_ERROR, "no DGPS servers within %dm.\n", (int)(DGPS_THRESHOLD/1000));
+	context->dsock = -2;	/* don't try this again */
+	return;
+    }
+    /*@ +usedef @*/
+
+    /* sort them and try the closest first */
+    qsort((void *)keep, SERVER_SAMPLE, sizeof(struct dgps_server_t), srvcmp);
+    for (sp = keep; sp < keep + SERVER_SAMPLE; sp++) {
+	if (sp->server[0] != '\0') {
+	    gpsd_report(LOG_INF,"%s is %dkm away.\n",sp->server,(int)(sp->dist/1000));
+	    if (dgpsip_open(context, sp->server) >= 0)
+		break;
+	}
+    }
+}