Introduce Qualcomm PDS service support

The Qualcomm PDS service provides location data on a wide range of
Qualcomm platforms. It used QMI encoded messages sent over a shared
memory link, implemented in Linux as AF_QIPCRTR.

A special service is available on port -2 on the local node in the
network, which provides functionality to the node address and port of
registered services by id. As the driver is opened this mechanism is
used to search for a registered PDS service in the system.

As the PDS driver is activated two messages are sent to the PDS service,
the first one configures which events the service will send to the
client (in our case NMEA reports) and the second starts the transmission
of these packets. Similarly when the driver is deactivated a stop
request is sent to the service.

Between the start and stop request the PDS service will send NMEA
messages to the PDS client at a rate of 1 Hz, the NMEA string is
extracted from the QMI encoded message and handed to the nmea_parse()
function.

The PDS driver is selected by the url pds://<host>, where host is either
a numerical identifier of the node in the AF_QIPCRTR network or the
string "any".

Signed-off-by: Bjorn Andersson <[email protected]>

SConstruct

@@ -155,6 +155,7 @@ boolopts = (
     ("ublox",         True,  "u-blox Protocol support"),
     ("fury",          True,  "Jackson Labs Fury and Firefly support"),
     ("nmea2000",      True,  "NMEA2000/CAN support"),
+    ("pds",           True,  "Qualcomm PDS support"),
     # Non-GPS protocols
     ("aivdm",         True,  "AIVDM support"),
     ("gpsclock",      True,  "GPSClock support"),
@@ -778,6 +779,14 @@ else:
         announce("You do not have kernel CANbus available.")
         env["nmea2000"] = False
 
+    if config.CheckHeader(["bits/sockaddr.h", "linux/qrtr.h"]):
+        confdefs.append("#define HAVE_LINUX_QRTR_H 1\n")
+        announce("You have kernel QRTR available.")
+    else:
+        confdefs.append("/* #undef HAVE_LINUX_QRTR_H */\n")
+        announce("You do not have kernel QRTR available.")
+        env["pds"] = False
+
     # check for C11 or better, and __STDC__NO_ATOMICS__ is not defined
     # before looking for stdatomic.h
     if ((config.CheckC11()
@@ -1121,6 +1130,7 @@ libgpsd_sources = [
     "driver_nmea0183.c",
     "driver_nmea2000.c",
     "driver_oncore.c",
+    "driver_pds.c",
     "driver_rtcm2.c",
     "driver_rtcm3.c",
     "driver_sirf.c",

driver_pds.c

@@ -0,0 +1,325 @@
+#include <sys/socket.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include "gpsd.h"
+#include "libgps.h"
+
+#if defined(PDS_ENABLE)
+#include "driver_pds.h"
+
+#include <linux/qrtr.h>
+
+#define QMI_PDS_SERVICE_ID	0x10
+#define QMI_PDS_VERSION		0x2
+
+struct qmi_header {
+	uint8_t type;
+	uint16_t txn;
+	uint16_t msg;
+	uint16_t len;
+} __attribute__((__packed__));
+
+struct qmi_tlv {
+	uint8_t key;
+	uint16_t len;
+	uint8_t value[];
+} __attribute__((__packed__));
+
+#define QMI_REQUEST			0
+#define QMI_INDICATION			4
+
+#define QMI_LOC_REG_EVENTS		0x21
+#define QMI_TLV_EVENT_MASK		1
+#define QMI_EVENT_MASK_NMEA		4
+
+#define QMI_LOC_START			0x22
+#define QMI_LOC_STOP			0x23
+#define QMI_TLV_SESSION_ID		1
+
+#define QMI_LOC_EVENT_NMEA		0x26
+#define QMI_TLV_NMEA			1
+
+static ssize_t qmi_pds_get(struct gps_device_t *session)
+{
+	struct sockaddr_qrtr sq;
+	socklen_t sl = sizeof(sq);
+	struct qmi_header *hdr;
+	struct qmi_tlv *tlv;
+	size_t buflen = sizeof(session->lexer.inbuffer);
+	size_t offset;
+	void *buf = session->lexer.inbuffer;
+	int ret;
+
+	ret = recvfrom(session->gpsdata.gps_fd, buf, buflen, 0,
+		       (struct sockaddr *)&sq, &sl);
+	if (ret < 0 && errno == EAGAIN) {
+		session->lexer.outbuflen = 0;
+		return 1;
+	} else if (ret < 0) {
+		gpsd_log(&session->context->errout, LOG_ERROR,
+			 "QRTR get: Unable to receive packet.\n");
+		return -1;
+	}
+
+	/* TODO: Validate sq to be our peer */
+
+	session->lexer.type = QMI_PDS_PACKET;
+
+	hdr = buf;
+	if (hdr->type != QMI_INDICATION ||
+	    hdr->msg != QMI_LOC_EVENT_NMEA) {
+		session->lexer.outbuflen = 0;
+		return ret;
+	}
+
+	offset = sizeof(*hdr);
+	while (offset < (size_t)ret) {
+		tlv = (struct qmi_tlv *)((char*)buf + offset);
+
+		if (offset + sizeof(*tlv) + tlv->len > (size_t)ret)
+			break;
+
+		if (tlv->key == QMI_TLV_NMEA) {
+			memcpy(session->lexer.outbuffer, tlv->value, tlv->len);
+			session->lexer.outbuffer[tlv->len] = 0;
+			session->lexer.outbuflen = tlv->len;
+			break;
+		}
+
+		offset += tlv->len;
+	}
+
+	return ret;
+}
+
+static gps_mask_t qmi_pds_parse_input(struct gps_device_t *session)
+{
+	return nmea_parse((char *)session->lexer.outbuffer, session);
+}
+
+static void qmi_pds_event_hook(struct gps_device_t *session, event_t event)
+{
+	struct qmi_header *hdr;
+	struct qmi_tlv *tlv;
+	static int txn_id;
+	char buf[128];
+	char *ptr;
+	int sock = session->gpsdata.gps_fd;
+	int ret;
+
+	switch (event) {
+	case event_deactivate:
+		ptr = buf;
+		hdr = (struct qmi_header *)ptr;
+		hdr->type = QMI_REQUEST;
+		hdr->txn = txn_id++;
+		hdr->msg = QMI_LOC_STOP;
+		hdr->len = sizeof(*tlv) + sizeof(uint8_t);
+		ptr += sizeof(*hdr);
+
+		tlv = (struct qmi_tlv *)ptr;
+		tlv->key = QMI_TLV_SESSION_ID;
+		tlv->len = sizeof(uint8_t);
+		*(uint8_t*)tlv->value = 1;
+		ptr += sizeof(*tlv) + sizeof(uint8_t);
+
+		ret = send(sock, buf, ptr - buf, 0);
+		if (ret < 0) {
+			gpsd_log(&session->context->errout, LOG_ERROR,
+				 "QRTR event_hook: failed to send STOP request.\n");
+			return;
+		}
+		break;
+	case event_reactivate:
+		ptr = buf;
+		hdr = (struct qmi_header *)ptr;
+		hdr->type = QMI_REQUEST;
+		hdr->txn = txn_id++;
+		hdr->msg = QMI_LOC_REG_EVENTS;
+		hdr->len = sizeof(*tlv) + sizeof(uint64_t);
+		ptr += sizeof(*hdr);
+
+		tlv = (struct qmi_tlv *)ptr;
+		tlv->key = QMI_TLV_EVENT_MASK;
+		tlv->len = sizeof(uint64_t);
+		*(uint64_t*)tlv->value = QMI_EVENT_MASK_NMEA;
+		ptr += sizeof(*tlv) + sizeof(uint64_t);
+
+		ret = send(sock, buf, ptr - buf, 0);
+		if (ret < 0) {
+			gpsd_log(&session->context->errout, LOG_ERROR,
+				 "QRTR event_hook: failed to send REG_EVENTS request.\n");
+			return;
+		}
+
+		ptr = buf;
+		hdr = (struct qmi_header *)ptr;
+		hdr->type = QMI_REQUEST;
+		hdr->txn = txn_id++;
+		hdr->msg = QMI_LOC_START;
+		hdr->len = sizeof(*tlv) + sizeof(uint8_t);
+		ptr += sizeof(*hdr);
+
+		tlv = (struct qmi_tlv *)(buf + sizeof(*hdr));
+		tlv->key = QMI_TLV_SESSION_ID;
+		tlv->len = sizeof(uint8_t);
+		*(uint8_t*)tlv->value = 1;
+		ptr += sizeof(*tlv) + sizeof(uint8_t);
+
+		ret = send(sock, buf, ptr - buf, 0);
+		if (ret < 0) {
+			gpsd_log(&session->context->errout, LOG_ERROR,
+				 "QRTR event_hook: failed to send START request.\n");
+			return;
+		}
+		break;
+	default:
+		break;
+	}
+}
+
+int qmi_pds_open(struct gps_device_t *session)
+{
+	struct sockaddr_qrtr sq_ctrl;
+	struct qrtr_ctrl_pkt pkt;
+	struct sockaddr_qrtr sq;
+	unsigned int pds_node = 0;
+	unsigned int pds_port = 0;
+	socklen_t sl = sizeof(sq_ctrl);
+	char *hostname;
+	char *endptr;
+	int hostid;
+	int flags;
+	int sock;
+	int ret;
+
+	hostname = session->gpsdata.dev.path + 6;
+	if (!strcmp(hostname, "any")) {
+		hostid = -1;
+	} else {
+		hostid = (int)strtol(hostname, &endptr, 10);
+		if (endptr == hostname) {
+			gpsd_log(&session->context->errout, LOG_ERROR,
+				 "QRTR open: Invalid node id.\n");
+			return -1;
+		}
+	}
+
+
+	sock = socket(AF_QIPCRTR, SOCK_DGRAM, 0);
+	if (sock < 0) {
+	        gpsd_log(&session->context->errout, LOG_ERROR,
+			 "QRTR open: Unable to get QRTR socket.\n");
+		return -1;
+	}
+
+	ret = getsockname(sock, (struct sockaddr *)&sq_ctrl, &sl);
+	if (ret < 0 || sq_ctrl.sq_family != AF_QIPCRTR || sl != sizeof(sq_ctrl)) {
+	        gpsd_log(&session->context->errout, LOG_ERROR,
+			 "QRTR open: Unable to acquire local address.\n");
+		close(sock);
+		return -1;
+	}
+
+	memset(&pkt, 0, sizeof(pkt));
+	pkt.cmd = QRTR_TYPE_NEW_LOOKUP;
+	pkt.server.service = QMI_PDS_SERVICE_ID;
+	pkt.server.instance = QMI_PDS_VERSION;
+
+	sq_ctrl.sq_port = QRTR_PORT_CTRL;
+	ret = sendto(sock, &pkt, sizeof(pkt), 0, (struct sockaddr *)&sq_ctrl, sizeof(sq_ctrl));
+	if (ret < 0) {
+	        gpsd_log(&session->context->errout, LOG_ERROR,
+			 "QRTR open: Unable to send lookup request.\n");
+		close(sock);
+		return -1;
+	}
+
+	for (;;) {
+		sl = sizeof(sq);
+
+		ret = recvfrom(sock, &pkt, sizeof(pkt), 0, (struct sockaddr *)&sq, &sl);
+		if (ret < 0) {
+			gpsd_log(&session->context->errout, LOG_ERROR,
+				 "QRTR open: Unable to receive lookup request.\n");
+			close(sock);
+			return -1;
+		}
+
+		if (sl != sizeof(sq) || sq.sq_node != sq_ctrl.sq_node ||
+		    sq.sq_port != sq_ctrl.sq_port) {
+			gpsd_log(&session->context->errout, LOG_ERROR,
+				 "QRTR open: Received message is not ctrl message, ignoring.\n");
+			continue;
+		}
+
+		if (pkt.cmd != QRTR_TYPE_NEW_SERVER)
+			continue;
+
+		/* All fields zero indicates end of lookup response */
+		if (!pkt.server.service && !pkt.server.instance &&
+		    !pkt.server.node && !pkt.server.port)
+			break;
+
+		/* Filter results based on specified node */
+		if (hostid != -1 && hostid != (int)pkt.server.node)
+			continue;
+
+		pds_node = pkt.server.node;
+		pds_port = pkt.server.port;
+	}
+
+	if (!pds_node && !pds_port) {
+		gpsd_log(&session->context->errout, LOG_ERROR,
+			 "QRTR open: No PDS service found.\n");
+		close(sock);
+		return -1;
+	}
+
+	flags = fcntl(sock, F_GETFL, 0);
+	flags |= O_NONBLOCK;
+	fcntl(sock, F_SETFL, flags);
+
+	gpsd_log(&session->context->errout, LOG_INF,
+		 "QRTR open: Found PDS at %d %d.\n", pds_node, pds_port);
+
+	sq.sq_family = AF_QIPCRTR;
+	sq.sq_node = pds_node;
+	sq.sq_port = pds_port;
+	ret = connect(sock, (struct sockaddr *)&sq, sizeof(sq));
+	if (ret < 0) {
+		gpsd_log(&session->context->errout, LOG_ERROR,
+			 "QRTR open: Failed to connect socket.\n");
+		close(sock);
+		return -1;
+	}
+
+	gpsd_switch_driver(session, "Qualcomm PDS");
+	session->gpsdata.gps_fd = sock;
+	session->sourcetype = source_qrtr;
+	session->servicetype = service_sensor;
+
+	return session->gpsdata.gps_fd;
+}
+
+void qmi_pds_close(struct gps_device_t *session)
+{
+	if (!BAD_SOCKET(session->gpsdata.gps_fd)) {
+		close(session->gpsdata.gps_fd);
+		INVALIDATE_SOCKET(session->gpsdata.gps_fd);
+	}
+}
+
+const struct gps_type_t driver_pds = {
+    .type_name      = "Qualcomm PDS",       /* full name of type */
+    .packet_type    = QMI_PDS_PACKET,	/* associated lexer packet type */
+    .flags	    = DRIVER_STICKY,	/* remember this */
+    .channels       = 12,		/* not an actual GPS at all */
+    .get_packet     = qmi_pds_get,	/* how to get a packet */
+    .parse_packet   = qmi_pds_parse_input,	/* how to interpret a packet */
+    .event_hook	    = qmi_pds_event_hook,
+};
+
+#endif /* of defined(PDS_ENABLE) */

driver_pds.h

@@ -0,0 +1,20 @@
+/*
+ * PDS on QRTR.
+ *
+ * The entry points for driver_pds
+ *
+ * This file is Copyright (c) 2018 by the GPSD project
+ * SPDX-License-Identifier: BSD-2-clause
+ */
+
+#ifndef _DRIVER_PDS_H_
+#define _DRIVER_PDS_H_
+
+#if defined(PDS_ENABLE)
+
+int qmi_pds_open(struct gps_device_t *session);
+
+void qmi_pds_close(struct gps_device_t *session);
+
+#endif /* of defined(PDS_ENABLE) */
+#endif /* of ifndef _DRIVER_PDS_H_ */

drivers.c

@@ -1744,6 +1744,7 @@ extern const struct gps_type_t driver_geostar;
 extern const struct gps_type_t driver_italk;
 extern const struct gps_type_t driver_navcom;
 extern const struct gps_type_t driver_nmea2000;
+extern const struct gps_type_t driver_pds;
 extern const struct gps_type_t driver_oncore;
 extern const struct gps_type_t driver_sirf;
 extern const struct gps_type_t driver_skytraq;
@@ -1838,6 +1839,10 @@ static const struct gps_type_t *gpsd_driver_array[] = {
     &driver_nmea2000,
 #endif /* NMEA2000_ENABLE */
 
+#ifdef PDS_ENABLE
+    &driver_pds,
+#endif /* PDS_ENABLE */
+
 #ifdef RTCM104V2_ENABLE
     &driver_rtcm104v2,
 #endif /* RTCM104V2_ENABLE */