sergiotarxz/nuttx-apps
sergiotarxz/nuttx-apps
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

NTP client: Fix a time calculation for the case of CPUs that do not support long long

Browse Source
This commit is contained in:
Gregory Nutt 2014-04-11 09:24:59 -06:00
parent e72ec4ad00
commit 396316881e
1 changed files with 38 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

49
netutils/ntpclient/ntpclient.c
View File

@ -229,14 +229,12 @@ static void ntpc_settime(FAR uint8_t *timestamp)
{ {
t32++; t32++;
} }
else
{ t0 += t16;
t0 += t16;
}
/* Get the second b16 term /* Get the second b16 term
* *
* b * 0x1d << 16) * b * (0x1d << 16)
*/ */
t16 = 0x001d * b0; t16 = 0x001d * b0;
@ -254,10 +252,8 @@ static void ntpc_settime(FAR uint8_t *timestamp)
{ {
t32++; t32++;
} }
else
{ t0 += t16;
t0 += t16;
}
/* t32 and t0 represent the 64 bit product. Now shift right by 23 bits to /* t32 and t0 represent the 64 bit product. Now shift right by 23 bits to
* accomplish the divide by by 2**23. * accomplish the divide by by 2**23.
@ -342,7 +338,7 @@ static int ntpc_daemon(int argc, char **argv)
* client architecture. A request is sent and then a NTP packet is received * client architecture. A request is sent and then a NTP packet is received
* and used to set the current time. * and used to set the current time.
* *
* NOTE that the scheduler is locked whenever this function runs. That * NOTE that the scheduler is locked whenever this loop runs. That
* assures both: (1) that there are no asynchronous stop requests and * assures both: (1) that there are no asynchronous stop requests and
* (2) that we are not suspended while in critical moments when we about * (2) that we are not suspended while in critical moments when we about
* to set the new time. This sounds harsh, but this function is suspended * to set the new time. This sounds harsh, but this function is suspended
@ -353,6 +349,8 @@ static int ntpc_daemon(int argc, char **argv)
sched_lock(); sched_lock();
while (g_ntpc_daemon.state == NTP_STOP_REQUESTED) while (g_ntpc_daemon.state == NTP_STOP_REQUESTED)
{ {
/* Format the transmit datagram */
memset(&xmit, 0, sizeof(xmit)); memset(&xmit, 0, sizeof(xmit));
xmit.lvm = MKLVM(0, 3, NTP_VERSION); xmit.lvm = MKLVM(0, 3, NTP_VERSION);
@ -364,6 +362,10 @@ static int ntpc_daemon(int argc, char **argv)
if (ret < 0) if (ret < 0)
{ {
/* Check if we received a signal. That is not an error but
* other error events will terminate the client.
*/
int errval = errno; int errval = errno;
if (errval != EINTR) if (errval != EINTR)
{ {
@ -380,18 +382,43 @@ static int ntpc_daemon(int argc, char **argv)
continue; continue;
} }
/* Attempt to receive a packet (with a timeout) */ /* Attempt to receive a packet (with a timeout that was set up via
* setsockopt() above)
*/
socklen = sizeof(struct sockaddr_in); socklen = sizeof(struct sockaddr_in);
nbytes = recvfrom(sd, (void *)&recv, sizeof(struct ntp_datagram_s), nbytes = recvfrom(sd, (void *)&recv, sizeof(struct ntp_datagram_s),
0, (FAR struct sockaddr *)&server, &socklen); 0, (FAR struct sockaddr *)&server, &socklen);
/* Check if the received message was long enough to be a valid NTP
* datagram.
*/
if (nbytes >= NTP_DATAGRAM_MINSIZE) if (nbytes >= NTP_DATAGRAM_MINSIZE)
{ {
svdbg("Setting time\n"); svdbg("Setting time\n");
ntpc_settime(recv.recvtimestamp); ntpc_settime(recv.recvtimestamp);
} }
/* Check for errors. Note that properly received, short datagrams
* are simply ignored.
*/
else if (nbytes < 0)
{
/* Check if we received a signal. That is not an error but
* other error events will terminate the client.
*/
int errval = errno;
if (errval != EINTR)
{
ndbg("ERROR: recvfrom() failed: %d\n", errval);
exitcode = EXIT_FAILURE;
break;
}
}
/* A full implementation of an NTP client would require much more. I /* A full implementation of an NTP client would require much more. I
* think we can skip most of that here. * think we can skip most of that here.
*/ */