Diff: NTPClient.cpp

Revision:

0:04a82df0f587

Child:

1:b221a8765b3f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/NTPClient.cpp	Fri May 25 13:48:49 2012 +0000
@@ -0,0 +1,202 @@
+/* NTPClient.cpp */
+/*
+Copyright (C) 2012 ARM Limited.
+
+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.
+*/
+
+#define __DEBUG__ 4 //Maximum verbosity
+#ifndef __MODULE__
+#define __MODULE__ "NTPClient.cpp"
+#endif
+
+#include "core/fwk.h"
+
+#include "NTPClient.h"
+
+#include "mbed.h" //time() and set_time()
+
+#define NTP_PORT 123
+#define NTP_CLIENT_PORT 0 //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)
+
+NTPClient::NTPClient()
+{
+
+
+}
+
+int NTPClient::setTime(const char* host, uint16_t port, uint32_t timeout)
+{
+  struct sockaddr_in serverAddr;
+
+  std::memset(&serverAddr, 0, sizeof(struct sockaddr_in));
+
+#if __DEBUG__ >= 3
+  time_t ctTime;
+  ctTime = time(NULL);
+  INFO("Time is set to (UTC): %s", ctime(&ctTime));
+#endif
+
+  //Resolve DNS if needed
+  if(serverAddr.sin_addr.s_addr == 0)
+  {
+    DBG("Resolving DNS address or populate hard-coded IP address");
+    struct hostent *server = socket::gethostbyname(host);
+    if(server == NULL)
+    {
+      return NET_NOTFOUND; //Fail
+    }
+    memcpy((char*)&serverAddr.sin_addr.s_addr, (char*)server->h_addr_list[0], server->h_length);
+  }
+
+  serverAddr.sin_family = AF_INET;
+  serverAddr.sin_port = htons(port);
+
+  //Now create & bind socket
+  DBG("Creating socket");
+  int sock  = socket::socket(AF_INET, SOCK_DGRAM, 0); //UDP socket
+  if (sock < 0)
+  {
+    ERR("Could not create socket");
+    return NET_OOM;
+  }
+  DBG("Handle is %d",sock);
+
+  //Create local address
+  struct sockaddr_in localhostAddr;
+
+  std::memset(&localhostAddr, 0, sizeof(struct sockaddr_in));
+
+  localhostAddr.sin_family = AF_INET;
+  localhostAddr.sin_port = htons(NTP_CLIENT_PORT); //Random port
+  localhostAddr.sin_addr.s_addr = htonl(INADDR_ANY); //Any local address
+
+  if ( socket::bind( sock, (struct sockaddr*)&localhostAddr, sizeof(localhostAddr)) < 0 ) //Listen on local port
+  {
+    ERR("Could not bind socket");
+    socket::close(sock);
+    return NET_OOM;
+  }
+
+  struct NTPPacket pkt;
+
+  //Now ping the server and wait for response
+  DBG("Ping");
+  //Prepare NTP Packet:
+  pkt.li = 0; //Leap Indicator : No warning
+  pkt.vn = 4; //Version Number : 4
+  pkt.mode = 3; //Client mode
+  pkt.stratum = 0; //Not relevant here
+  pkt.poll = 0; //Not significant as well
+  pkt.precision = 0; //Neither this one is
+
+  pkt.rootDelay = 0; //Or this one
+  pkt.rootDispersion = 0; //Or that one
+  pkt.refId = 0; //...
+
+  pkt.refTm_s = 0;
+  pkt.origTm_s = 0;
+  pkt.rxTm_s = 0;
+  pkt.txTm_s = htonl( NTP_TIMESTAMP_DELTA + time(NULL) ); //WARN: We are in LE format, network byte order is BE
+
+  pkt.refTm_f = pkt.origTm_f = pkt.rxTm_f = pkt.txTm_f = 0;
+
+  //Set timeout, non-blocking and wait using select
+  if( socket::sendto( sock, (void*)&pkt, sizeof(NTPPacket), 0, (struct sockaddr*)&serverAddr, sizeof(serverAddr) ) < 0 )
+  {
+    ERR("Could not send packet");
+    socket::close(sock);
+    return NET_CONN;
+  }
+
+  //Wait for socket to be readable
+  //Creating FS set
+  fd_set socksSet;
+  FD_ZERO(&socksSet);
+  FD_SET(sock, &socksSet);
+  struct timeval t_val;
+  t_val.tv_sec = timeout / 1000;
+  t_val.tv_usec = (timeout - (t_val.tv_sec * 1000)) * 1000;
+  int ret = socket::select(FD_SETSIZE, &socksSet, NULL, NULL, &t_val);
+  if(ret <= 0 || !FD_ISSET(sock, &socksSet))
+  {
+    ERR("Timeout while waiting for answer");
+    socket::close(sock);
+    return NET_TIMEOUT; //Timeout
+  }
+
+  //Read response
+  DBG("Pong");
+  struct sockaddr_in respAddr;
+  socklen_t respAddrLen = sizeof(respAddr);
+  do
+  {
+    ret = socket::recvfrom( sock, (void*)&pkt, sizeof(NTPPacket), 0, (struct sockaddr*)&respAddr, &respAddrLen);
+    if(ret < 0)
+    {
+      ERR("Could not receive packet");
+      socket::close(sock);
+      return NET_CONN;
+    }
+  } while( respAddr.sin_addr.s_addr != serverAddr.sin_addr.s_addr);
+
+  if(ret < sizeof(NTPPacket)) //TODO: Accept chunks
+  {
+    ERR("Receive packet size does not match");
+    socket::close(sock);
+    return NET_PROTOCOL;
+  }
+
+  if( pkt.stratum == 0)  //Kiss of death message : Not good !
+  {
+    ERR("Kissed to death!");
+    socket::close(sock);
+    return NTP_PORT;
+  }
+
+  //Correct Endianness
+  pkt.refTm_s = ntohl( pkt.refTm_s );
+  pkt.refTm_f = ntohl( pkt.refTm_f );
+  pkt.origTm_s = ntohl( pkt.origTm_s );
+  pkt.origTm_f = ntohl( pkt.origTm_f );
+  pkt.rxTm_s = ntohl( pkt.rxTm_s );
+  pkt.rxTm_f = ntohl( pkt.rxTm_f );
+  pkt.txTm_s = ntohl( pkt.txTm_s );
+  pkt.txTm_f = ntohl( pkt.txTm_f );
+
+  //Compute offset, see RFC 4330 p.13
+  uint32_t destTm_s = (NTP_TIMESTAMP_DELTA + time(NULL));
+  int64_t offset = ( (int64_t)( pkt.rxTm_s - pkt.origTm_s ) + (int64_t) ( pkt.txTm_s - destTm_s ) ) / 2; //Avoid overflow
+  DBG("Sent @%ul", pkt.txTm_s);
+  DBG("Offset: %ul", offset);
+  //Set time accordingly
+  set_time( time(NULL) + offset );
+
+#if __DEBUG__ >= 3
+  ctTime = time(NULL);
+  INFO("Time is now (UTC): %s", ctime(&ctTime));
+#endif
+
+  socket::close(sock);
+
+  return OK;
+}
+