/// <summary>
/// A sniffer entry (sniffer-mac, client-mac, rssi, and time) is added to currently built measurements.
/// The procedures is the same for online and offline measurements - the only difference is that we do not track changes to
/// online measurements as we are not interested in saving them persistently (at least not at the present time)
/// </summary>
/// <param name="snifferMac">The sniffer's mac address</param>
/// <param name="clientMac">The client's mac adress</param>
/// <param name="rssi">The client's rssi as measured by the sniffer</param>
/// <param name="mode">'Offline' or 'Online' to help distinguish whether we want to save the data persistently</param>
/// <param name="time">The time the sniffer entry was made. </param>
private static void addToMeasurement(string snifferMac, string clientMac, int rssi, DateTime time)
{
Mode mode;
//First, determine the mode.
if (currentOfflineMeasurements.ContainsKey(clientMac))
{
mode = Mode.Offline;
}
else if (currentOnlineMeasurements.ContainsKey(clientMac))
{
mode = Mode.Online;
}
else
{
return; //Unknown client mac
}
ConcurrentDictionary <string, SnifferWifiMeasurement> dic = getMeasurementDictionary(mode);
SnifferWifiMeasurement curWifiMeasurement = dic[clientMac];
//Update end meas time (even more may come..)
curWifiMeasurement.meas_time_end = time;
//Add or update histogram with snifferMac, rssi value
SnifferHistogram curHist = curWifiMeasurement.SnifferHistograms.FirstOrDefault(h => h.Mac == snifferMac && h.value == rssi);
if (curHist == null) //insert new histogram
{
curHist = new SnifferHistogram();
curHist.Mac = snifferMac;
curHist.value = rssi;
curHist.count = 0;
curWifiMeasurement.SnifferHistograms.Add(curHist);
curHist.SnifferWifiMeasurement = curWifiMeasurement;
if (mode == Mode.Offline)
{
context.AddRelatedObject(curWifiMeasurement, "SnifferHistograms", curHist);
}
}
curHist.count++; //yet another count for this rssi value
//In the offline mode we actually save the data.
if (mode == Mode.Offline)
{
context.UpdateObject(curWifiMeasurement);
context.UpdateObject(curHist);
}
}
//Public visibility so we can test it (directly) via unit tests
public static SnifferWifiMeasurement getNStrongestAPMeasurement(SnifferWifiMeasurement measurement, int n)
{
if (measurement.getMACs().Count < n)
{
return(measurement);
}
SortedDictionary <double, String> strongestAPs = new SortedDictionary <double, String>();
//Find the n strongest macs
//
foreach (String mac in measurement.getMACs()) //all APs in sample
{
double curMacVal = measurement.getAvgDbM(mac);
while (strongestAPs.ContainsKey(curMacVal))
{
curMacVal += 0.0001;
}
strongestAPs.Add(curMacVal, mac);
//NB: TreeMap sorts members in ascending order!
//Thus, we remove from the head to keep the strongest values
if (strongestAPs.Count > n)
{
strongestAPs.Remove(strongestAPs.First().Key);
}
}
//Create new measurement containing n strongest macs
SnifferWifiMeasurement result = new SnifferWifiMeasurement();
foreach (double d in strongestAPs.Keys)
{
SnifferHistogram h = new SnifferHistogram();
h.Mac = strongestAPs[d];
h.value = (int)d;
h.count = 1;
result.SnifferHistograms.Add(h);
//result.addValue(strongestAPs.get(d), (int)d);
}
return(result);
}
public void AddToSnifferHistograms(SnifferHistogram snifferHistogram)
{
base.AddObject("SnifferHistograms", snifferHistogram);
}
public static SnifferHistogram CreateSnifferHistogram(int ID, string mac, int value, int count, int wifiMeasurement_ID)
{
SnifferHistogram snifferHistogram = new SnifferHistogram();
snifferHistogram.ID = ID;
snifferHistogram.Mac = mac;
snifferHistogram.value = value;
snifferHistogram.count = count;
snifferHistogram.WifiMeasurement_ID = wifiMeasurement_ID;
return snifferHistogram;
}
