firmware/src/plugins/PositionPlugin.cpp

#include "PositionPlugin.h"
#include "MeshService.h"
#include "NodeDB.h"
#include "RTC.h"
#include "Router.h"
#include "configuration.h"
#include "gps/GeoCoord.h"

PositionPlugin *positionPlugin;

PositionPlugin::PositionPlugin()
    : ProtobufPlugin("position", PortNum_POSITION_APP, Position_fields), concurrency::OSThread("PositionPlugin")
{
    isPromiscuous = true;          // We always want to update our nodedb, even if we are sniffing on others
    setIntervalFromNow(60 * 1000); // Send our initial position 60 seconds after we start (to give GPS time to setup)
}

bool PositionPlugin::handleReceivedProtobuf(const MeshPacket &mp, Position *pptr)
{
    auto p = *pptr;

    // If inbound message is a replay (or spoof!) of our own messages, we shouldn't process
    // (why use second-hand sources for our own data?)

    // FIXME this can in fact happen with packets sent from EUD (src=RX_SRC_USER)
    // to set fixed location, EUD-GPS location or just the time (see also issue #900)
    if (nodeDB.getNodeNum() == getFrom(&mp)) {
        DEBUG_MSG("Incoming update from MYSELF\n");
        // DEBUG_MSG("Ignored an incoming update from MYSELF\n");
        // return false;
    }

    // Log packet size and list of fields
    DEBUG_MSG("POSITION node=%08x l=%d %s%s%s%s%s%s%s%s%s%s%s%s%s%s\n", getFrom(&mp), mp.decoded.payload.size,
              p.latitude_i ? "LAT " : "", p.longitude_i ? "LON " : "", p.altitude ? "MSL " : "", p.altitude_hae ? "HAE " : "",
              p.alt_geoid_sep ? "GEO " : "", p.PDOP ? "PDOP " : "", p.HDOP ? "HDOP " : "", p.VDOP ? "VDOP " : "",
              p.sats_in_view ? "SIV " : "", p.fix_quality ? "FXQ " : "", p.fix_type ? "FXT " : "", p.pos_timestamp ? "PTS " : "",
              p.time ? "TIME " : "", p.battery_level ? "BAT " : "");

    if (p.time) {
        struct timeval tv;
        uint32_t secs = p.time;

        tv.tv_sec = secs;
        tv.tv_usec = 0;

        perhapsSetRTC(RTCQualityFromNet, &tv);
    }

    nodeDB.updatePosition(getFrom(&mp), p);

    return false; // Let others look at this message also if they want
}

MeshPacket *PositionPlugin::allocReply()
{
    NodeInfo *node = service.refreshMyNodeInfo(); // should guarantee there is now a position
    assert(node->has_position);

    // configuration of POSITION packet
    //   consider making this a function argument?
    uint32_t pos_flags = radioConfig.preferences.position_flags;

    // Populate a Position struct with ONLY the requested fields
    Position p = Position_init_default; //   Start with an empty structure

    // lat/lon are unconditionally included - IF AVAILABLE!
    p.latitude_i = node->position.latitude_i;
    p.longitude_i = node->position.longitude_i;
    p.time = node->position.time;

    if (pos_flags & PositionFlags_POS_BATTERY)
        p.battery_level = node->position.battery_level;

    if (pos_flags & PositionFlags_POS_ALTITUDE) {
        if (pos_flags & PositionFlags_POS_ALT_MSL)
            p.altitude = node->position.altitude;
        else
            p.altitude_hae = node->position.altitude_hae;

        if (pos_flags & PositionFlags_POS_GEO_SEP)
            p.alt_geoid_sep = node->position.alt_geoid_sep;
    }

    if (pos_flags & PositionFlags_POS_DOP) {
        if (pos_flags & PositionFlags_POS_HVDOP) {
            p.HDOP = node->position.HDOP;
            p.VDOP = node->position.VDOP;
        } else
            p.PDOP = node->position.PDOP;
    }

    if (pos_flags & PositionFlags_POS_SATINVIEW)
        p.sats_in_view = node->position.sats_in_view;

    if (pos_flags & PositionFlags_POS_TIMESTAMP)
        p.pos_timestamp = node->position.pos_timestamp;

    // Strip out any time information before sending packets to other nodes - to keep the wire size small (and because other
    // nodes shouldn't trust it anyways) Note: we allow a device with a local GPS to include the time, so that gpsless
    // devices can get time.
    if (getRTCQuality() < RTCQualityGPS) {
        DEBUG_MSG("Stripping time %u from position send\n", p.time);
        p.time = 0;
    } else
        DEBUG_MSG("Providing time to mesh %u\n", p.time);

    return allocDataProtobuf(p);
}

void PositionPlugin::sendOurPosition(NodeNum dest, bool wantReplies)
{
    // cancel any not yet sent (now stale) position packets
    if (prevPacketId) // if we wrap around to zero, we'll simply fail to cancel in that rare case (no big deal)
        service.cancelSending(prevPacketId);

    MeshPacket *p = allocReply();
    p->to = dest;
    p->decoded.want_response = wantReplies;
    p->priority = MeshPacket_Priority_BACKGROUND;
    prevPacketId = p->id;

    service.sendToMesh(p);
}

int32_t PositionPlugin::runOnce()
{
    NodeInfo *node = nodeDB.getNode(nodeDB.getNodeNum());

    radioConfig.preferences.position_broadcast_smart = true;

    // We limit our GPS broadcasts to a max rate
    uint32_t now = millis();
    if (lastGpsSend == 0 || now - lastGpsSend >= getPref_position_broadcast_secs() * 1000) {

        lastGpsSend = now;

        lastGpsLatitude = node->position.latitude_i;
        lastGpsLongitude = node->position.longitude_i;

        // If we changed channels, ask everyone else for their latest info
        bool requestReplies = currentGeneration != radioGeneration;
        currentGeneration = radioGeneration;

        DEBUG_MSG("Sending pos@%x:6 to mesh (wantReplies=%d)\n", node->position.pos_timestamp, requestReplies);
        sendOurPosition(NODENUM_BROADCAST, requestReplies);
    } else if (radioConfig.preferences.position_broadcast_smart == true) {
        NodeInfo *node = service.refreshMyNodeInfo(); // should guarantee there is now a position

        if (node->has_position && (node->position.latitude_i != 0 || node->position.longitude_i != 0)) {
            float distance = GeoCoord::latLongToMeter(lastGpsLatitude * 1e-7, lastGpsLongitude * 1e-7,
                                                      node->position.latitude_i * 1e-7, node->position.longitude_i * 1e-7);

            /* Please don't change these values. This accomodates for possible poor positioning
               in the event the GPS has a poor satelite lock.
               */
            const uint8_t distanceTravel = 150;

            /* Minimum time between position updates.
               Note: At an average walking speed of 3.5mph, it takes 90 seconds to travel 150 meters.
            */
            const uint8_t timeTravel = 60;

            // If the distance traveled since the last update is greater than 100 meters
            //   and it's been at least 60 seconds since the last update
            if ((abs(distance) >= distanceTravel) &&
                (now - lastGpsSend >= timeTravel * 1000)
                ) {
                bool requestReplies = currentGeneration != radioGeneration;
                currentGeneration = radioGeneration;

                DEBUG_MSG("Sending smart pos@%x:6 to mesh (wantReplies=%d)\n", node->position.pos_timestamp, requestReplies);
                sendOurPosition(NODENUM_BROADCAST, requestReplies);

                /* Update lastGpsSend to now. This means if the device is stationary, then
                   getPref_position_broadcast_secs will still apply.
                */
                lastGpsSend = now;
            }
        }
    }

    return 5000; // to save power only wake for our callback occasionally
}