Add NTP Local Server Library

lib/ArduinoNTPd/NTPServer.cpp

@@ -0,0 +1,79 @@
+/*
+ * File: NTPServer.cpp
+ * Description:
+ *   NTP server implementation.
+ * Author: Mooneer Salem <mooneer@gmail.com>
+ * License: New BSD License
+ */
+
+
+#include <WiFiUdp.h>
+
+#include "NTPPacket.h"
+#include "NTPServer.h"
+
+#define NTP_PORT 123
+#define NTP_TIMESTAMP_DIFF     (2208988800)    // 1900 to 1970 in seconds
+
+bool NtpServer::beginListening()
+{
+    if (timeServerPort_.begin(NTP_PORT)){
+      return true;
+    }
+    return false;
+}
+
+bool NtpServer::processOneRequest(uint32_t utc, uint32_t millisecs) 
+{
+    // We need the time we've received the packet in our response.
+    uint32_t recvSecs =  utc + NTP_TIMESTAMP_DIFF;
+    double recvFractDouble = (double)millisecs/0.00023283064365386963; // millisec/((10^6)/(2^32))
+    uint32_t recvFract = (double)recvFractDouble; //TODO: really handle this!!!
+    bool processed = false;
+    
+    int packetDataSize = timeServerPort_.parsePacket();
+    if (packetDataSize && packetDataSize >= NtpPacket::PACKET_SIZE)
+    {
+        // Received what is probably an NTP packet. Read it in and verify
+        // that it's legit.
+        NtpPacket packet;
+        timeServerPort_.read((char*)&packet, NtpPacket::PACKET_SIZE);
+        // TODO: verify packet.
+
+        // Populate response.
+        packet.swapEndian();        
+        packet.leapIndicator(0);
+        packet.versionNumber(4);
+        packet.mode(4);
+        packet.stratum = 2; // I guess stratum 1 is too optimistic
+        packet.poll = 10; // 6-10 per RFC 5905.
+        packet.precision = -21; // ~0.5 microsecond precision.
+        packet.rootDelay = 0; //60 * (0xFFFF / 1000); // ~60 milliseconds, TBD
+        packet.rootDispersion = 0; //10 * (0xFFFF / 1000); // ~10 millisecond dispersion, TBD
+        packet.referenceId[0] = 'G';
+        packet.referenceId[1] = 'P';
+        packet.referenceId[2] = 'S';
+        packet.referenceId[3] = 0;
+        packet.referenceTimestampSeconds = utc;
+        packet.referenceTimestampFraction = recvFract;
+        packet.originTimestampSeconds = packet.transmitTimestampSeconds;
+        packet.originTimestampFraction = packet.transmitTimestampFraction;
+        packet.receiveTimestampSeconds = recvSecs;
+        packet.receiveTimestampFraction = recvFract;
+        
+        // ...and the transmit time.
+        // timeSource_.now(&packet.transmitTimestampSeconds, &packet.transmitTimestampFraction);
+        
+        // Now transmit the response to the client.
+        packet.swapEndian();
+        timeServerPort_.beginPacket(timeServerPort_.remoteIP(), timeServerPort_.remotePort());
+        for (int count = 0; count < NtpPacket::PACKET_SIZE; count++)
+        {
+            timeServerPort_.write(packet.packet()[count]);
+        }
+        timeServerPort_.endPacket();
+        processed = true;
+    } 
+    
+    return processed;
+}