diff options
| -rw-r--r-- | apps/netutils/ntpclient/ntpclient.c | 49 |
1 files changed, 38 insertions, 11 deletions
diff --git a/apps/netutils/ntpclient/ntpclient.c b/apps/netutils/ntpclient/ntpclient.c index 5ba41aa56..3878f02f2 100644 --- a/apps/netutils/ntpclient/ntpclient.c +++ b/apps/netutils/ntpclient/ntpclient.c @@ -229,14 +229,12 @@ static void ntpc_settime(FAR uint8_t *timestamp) { t32++; } - else - { - t0 += t16; - } + + t0 += t16; /* Get the second b16 term * - * b * 0x1d << 16) + * b * (0x1d << 16) */ t16 = 0x001d * b0; @@ -254,10 +252,8 @@ static void ntpc_settime(FAR uint8_t *timestamp) { t32++; } - else - { - t0 += t16; - } + + t0 += t16; /* t32 and t0 represent the 64 bit product. Now shift right by 23 bits to * 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 * 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 * (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 @@ -353,6 +349,8 @@ static int ntpc_daemon(int argc, char **argv) sched_lock(); while (g_ntpc_daemon.state == NTP_STOP_REQUESTED) { + /* Format the transmit datagram */ + memset(&xmit, 0, sizeof(xmit)); xmit.lvm = MKLVM(0, 3, NTP_VERSION); @@ -364,6 +362,10 @@ static int ntpc_daemon(int argc, char **argv) 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; if (errval != EINTR) { @@ -380,18 +382,43 @@ static int ntpc_daemon(int argc, char **argv) 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); nbytes = recvfrom(sd, (void *)&recv, sizeof(struct ntp_datagram_s), 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) { svdbg("Setting time\n"); 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 * think we can skip most of that here. */ |