Diff: services/ntp/NTPClient.cpp

Revision:

0:ac21159e27f4

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/services/ntp/NTPClient.cpp	Fri Jul 02 17:21:58 2010 +0000
@@ -0,0 +1,331 @@
+
+/*
+Copyright (c) 2010 Donatien Garnier (donatiengar [at] gmail [dot] com)
+ 
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+ 
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+ 
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+
+#include "NTPClient.h"
+
+#include <stdio.h>
+
+//#define __DEBUG
+#include "dbg/dbg.h"
+
+#define NTP_PORT 123
+#define NTP_CLIENT_PORT 0//50420 //Random port
+#define NTP_REQUEST_TIMEOUT 15000
+#define NTP_TIMESTAMP_DELTA 2208988800ull //Diff btw a UNIX timestamp (Starting Jan, 1st 1970) and a NTP timestamp (Starting Jan, 1st 1900)
+
+#define htons( x ) ( (( x << 8 ) & 0xFF00) | (( x >> 8 ) & 0x00FF) )
+#define ntohs( x ) (htons(x))
+
+#define htonl( x ) ( (( x << 24 ) & 0xFF000000)  \
+                   | (( x <<  8 ) & 0x00FF0000)  \
+                   | (( x >>  8 ) & 0x0000FF00)  \
+                   | (( x >> 24 ) & 0x000000FF)  )
+#define ntohl( x ) (htonl(x))
+
+NTPClient::NTPClient() : NetService(false), m_state(NTP_PING), m_pCbItem(NULL), m_pCbMeth(NULL), m_pCb(NULL),
+m_watchdog(), m_timeout(0), m_closed(true), m_host(), m_pDnsReq(NULL), m_blockingResult(NTP_PROCESSING)
+{
+  setTimeout(NTP_REQUEST_TIMEOUT);
+  DBG("\r\nNew NTPClient %p\r\n",this);
+}
+
+NTPClient::~NTPClient()
+{
+  close();
+}
+
+//High level setup functions
+NTPResult NTPClient::setTime(const Host& host) //Blocking
+{
+  doSetTime(host);
+  return blockingProcess();
+}
+
+NTPResult NTPClient::setTime(const Host& host, void (*pMethod)(NTPResult)) //Non blocking
+{
+  setOnResult(pMethod);
+  doSetTime(host);
+  return NTP_PROCESSING;
+}
+
+#if 0 //For doc only
+template<class T> 
+NTPResult NTPClient::setTime(const Host& host, T* pItem, void (T::*pMethod)(NTPResult)) //Non blocking
+{
+  setOnResult(pItem, pMethod);
+  doSetTime(host);
+  return NTP_PROCESSING;
+}
+#endif
+
+void NTPClient::doSetTime(const Host& host)
+{
+  init();
+  resetTimeout();
+  m_host = host;
+  if(!m_host.getPort())
+  {
+    m_host.setPort(NTP_PORT);
+  }
+  if(m_host.getIp().isNull())
+  {
+    //DNS query required
+    m_pDnsReq = new DNSRequest();
+    DBG("\r\nNTPClient : DNSRequest %p\r\n", m_pDnsReq);
+    m_pDnsReq->setOnReply(this, &NTPClient::onDNSReply);
+    m_pDnsReq->resolve(&m_host);
+    return;
+  }
+  open();
+}
+
+void NTPClient::setOnResult( void (*pMethod)(NTPResult) )
+{
+  m_pCb = pMethod;
+}
+
+void NTPClient::close()
+{
+  if(m_closed)
+    return;
+  m_closed = true; //Prevent recursive calling or calling on an object being destructed by someone else
+  m_watchdog.stop();
+  m_pUDPSocket->resetOnEvent();
+  m_pUDPSocket->close();
+  delete m_pUDPSocket;
+  if( m_pDnsReq )
+  {
+    m_pDnsReq->close();
+    delete m_pDnsReq;
+    m_pDnsReq = NULL;
+  }
+}
+
+void NTPClient::poll() //Called by NetServices
+{
+  if( (!m_closed) && (m_watchdog.read_ms() >= m_timeout) )
+  {
+    onTimeout();
+  }
+}
+
+void NTPClient::init() //Create and setup socket if needed
+{
+  if(!m_closed) //Already opened
+    return;
+  m_state = NTP_PING;
+  m_pUDPSocket = new UDPSocket;
+  m_pUDPSocket->setOnEvent(this, &NTPClient::onUDPSocketEvent);
+  m_closed = false;
+  DBG("NTPClient: Init OK\n");
+}
+
+void NTPClient::open()
+{
+  resetTimeout();
+  DBG("Opening connection\n");
+  m_state = NTP_PING;
+  Host localhost(IpAddr(127,0,0,1), NTP_CLIENT_PORT, "localhost");
+  m_pUDPSocket->bind(localhost);
+  set_time( 1280000000 ); //End of July 2010... just there to limit offset range
+  process();
+}
+
+#define MIN(a,b) ((a)<(b))?(a):(b)
+void NTPClient::process() //Main state-machine
+{
+  int len;
+  Host host;
+  
+  switch(m_state)
+  {
+  case NTP_PING:
+    DBG("\r\nPing\r\n");
+    //Prepare NTP Packet:
+    m_pkt.li = 0; //Leap Indicator : No warning
+    m_pkt.vn = 4; //Version Number : 4
+    m_pkt.mode = 3; //Client mode
+    m_pkt.stratum = 0; //Not relevant here
+    m_pkt.poll = 0; //Not significant as well
+    m_pkt.precision = 0; //Neither this one is
+    
+    m_pkt.rootDelay = 0; //Or this one
+    m_pkt.rootDispersion = 0; //Or that one
+    m_pkt.refId = 0; //...
+    
+    m_pkt.refTm_s = 0;
+    m_pkt.origTm_s = 0;
+    m_pkt.rxTm_s = 0;
+    m_pkt.txTm_s = htonl( NTP_TIMESTAMP_DELTA + time(NULL) ); //WARN: We are in LE format, network byte order is BE
+    
+    m_pkt.refTm_f = m_pkt.origTm_f = m_pkt.rxTm_f = m_pkt.txTm_f = 0;
+    
+    //Hex Dump:
+    DBG("\r\nDump Tx:\r\n");
+    for(int i = 0; i< sizeof(NTPPacket); i++)
+    {
+      DBG("%02x ", *((char*)&m_pkt + i));
+    }
+    DBG("\r\n\r\n");
+    
+    len = m_pUDPSocket->sendto( (char*)&m_pkt, sizeof(NTPPacket), &m_host );
+    if(len < sizeof(NTPPacket))
+      { onResult(NTP_PRTCL); close(); return; }
+      
+    m_state = NTP_PONG; 
+          
+    break;
+  
+  case NTP_PONG:
+    DBG("\r\nPong\r\n");
+    while( len = m_pUDPSocket->recvfrom( (char*)&m_pkt, sizeof(NTPPacket), &host ) )
+    {
+      if( len <= 0 )
+        break;
+      if( !host.getIp().isEq(m_host.getIp()) )
+        continue; //Not our packet
+      if( len > 0 )
+        break;
+    }
+    
+    if(len == 0)
+      return; //Wait for the next packet
+    
+    if(len < 0)
+      { onResult(NTP_PRTCL); close(); return; }
+    
+    if(len < sizeof(NTPPacket)) //TODO: Accept chunks
+      { onResult(NTP_PRTCL); close(); return; }
+      
+    //Hex Dump:
+    DBG("\r\nDump Rx:\r\n");
+    for(int i = 0; i< sizeof(NTPPacket); i++)
+    {
+      DBG("%02x ", *((char*)&m_pkt + i));
+    }
+    DBG("\r\n\r\n");
+      
+    if( m_pkt.stratum == 0)  //Kiss of death message : Not good !
+    {
+      onResult(NTP_PRTCL); close(); return;
+    }
+    
+    //Correct Endianness
+    m_pkt.refTm_s = ntohl( m_pkt.refTm_s );
+    m_pkt.refTm_f = ntohl( m_pkt.refTm_f );
+    m_pkt.origTm_s = ntohl( m_pkt.origTm_s );
+    m_pkt.origTm_f = ntohl( m_pkt.origTm_f );
+    m_pkt.rxTm_s = ntohl( m_pkt.rxTm_s );
+    m_pkt.rxTm_f = ntohl( m_pkt.rxTm_f );
+    m_pkt.txTm_s = ntohl( m_pkt.txTm_s );
+    m_pkt.txTm_f = ntohl( m_pkt.txTm_f );
+    
+    //Compute offset, see RFC 4330 p.13
+    uint32_t destTm_s = (NTP_TIMESTAMP_DELTA + time(NULL));
+    //int32_t origTm = (int32_t) ((uint64_t) m_pkt.origTm - NTP_TIMESTAMP_DELTA); //Convert in local 32 bits timestamps
+    //int32_t rxTm = (int32_t) ((uint64_t) m_pkt.rxTm - NTP_TIMESTAMP_DELTA); //Convert in local 32 bits timestamps
+    //int32_t txTm = (int32_t) ((uint64_t) m_pkt.txTm - NTP_TIMESTAMP_DELTA); //Convert in local 32 bits timestamps
+   // int64_t offset = ( ( ( m_pkt.rxTm_s - m_pkt.origTm_s ) + ( m_pkt.txTm_s - destTm_s ) ) << 32 + ( ( m_pkt.rxTm_f - m_pkt.origTm_f ) + ( m_pkt.txTm_f - 0 ) ) ) / 2;
+    int64_t offset = ( (int64_t)( m_pkt.rxTm_s - m_pkt.origTm_s ) + (int64_t) ( m_pkt.txTm_s - destTm_s ) ) / 2; //Avoid overflow
+    DBG("\r\nSent @%d\r\n", m_pkt.txTm_s);
+    DBG("\r\nOffset: %d\r\n", offset);
+    //Set time accordingly
+    set_time( time(NULL) + (offset /*>> 32*/) );
+    
+    onResult(NTP_OK);
+    close();
+      
+    break;
+  }
+}
+
+void NTPClient::setTimeout(int ms)
+{
+  m_timeout = ms;
+}
+
+void NTPClient::resetTimeout()
+{
+  m_watchdog.reset();
+  m_watchdog.start();
+}
+
+void NTPClient::onTimeout() //Connection has timed out
+{
+  close();
+  onResult(NTP_TIMEOUT);
+}
+
+void NTPClient::onDNSReply(DNSReply r)
+{
+  if(m_closed)
+  {
+    DBG("\r\nWARN: Discarded\r\n");
+    return;
+  }
+  
+  if( r != DNS_FOUND )
+  {
+    DBG("\r\nCould not resolve hostname.\r\n");
+    onResult(NTP_DNS);
+    close();
+    return;
+  }
+  DBG("\r\nDNS resolved.\r\n");
+  m_pDnsReq->close();
+  delete m_pDnsReq;
+  m_pDnsReq=NULL;
+  open();
+}
+  
+void NTPClient::onUDPSocketEvent(UDPSocketEvent e)
+{
+  resetTimeout();
+  switch(e)
+  {
+  case UDPSOCKET_READABLE: //The only event for now
+    resetTimeout();
+    process();
+    break;
+  }
+}
+
+void NTPClient::onResult(NTPResult r) //Must be called by impl when the request completes
+{
+  if(m_pCbItem && m_pCbMeth)
+    (m_pCbItem->*m_pCbMeth)(r);
+  else if(m_pCb)
+    m_pCb(r);
+  m_blockingResult = r; //Blocking mode
+}
+
+NTPResult NTPClient::blockingProcess() //Called in blocking mode, calls Net::poll() until return code is available
+{
+  m_blockingResult = NTP_PROCESSING;
+  do
+  {
+    Net::poll();
+  } while(m_blockingResult == NTP_PROCESSING);
+  Net::poll(); //Necessary for cleanup
+  return m_blockingResult;
+}