Revision 2:a3aec199dc7c, committed 2019-05-26

Comitter:

sjalloq

Date:

Sun May 26 08:46:35 2019 +0100

Parent:

1:099750f42b02

Commit message:

ntp-client : fork from Alix955/code/ntp-client

- sockets should not be setup as blocking if you want to use a timeout. This
resulted in the socket hanging when packets went missing.

Changed in this revision

--- a/NTPClient.cpp	Fri Dec 07 13:07:56 2018 +0000
+++ b/NTPClient.cpp	Sun May 26 08:46:35 2019 +0100
@@ -1,58 +1,70 @@
 #include "ntp-client/NTPClient.h"
 #include "mbed.h"
 
-NTPClient::NTPClient(NetworkInterface *iface)
-: iface(iface), nist_server_address((char *)NTP_DEFULT_NIST_SERVER_ADDRESS), nist_server_port(NTP_DEFULT_NIST_SERVER_PORT) {
+NTPClient::NTPClient(NetworkInterface *iface) :	iface(iface), 
+												nist_server_address((char *)NTP_DEFULT_NIST_SERVER_ADDRESS), 
+												nist_server_port(NTP_DEFULT_NIST_SERVER_PORT) {
 }
 
-void NTPClient::set_server(char* server, int port){
+void NTPClient::set_server(char* server, int port) {
     nist_server_address = server;
-    nist_server_port = port;
+    nist_server_port    = port;
 }
 
+/* The timeout value is in uS.  A sensible positive value is >5K to 
+	avoid the timeout firing on slow responses.  Note that this is UDP
+	so there is the likely possibility that the packet will be lost. 
+	
+	A timeout value of 0 corresponds to set_blocking(false).
+	A timeout value of -1 corresponds to set_blocking(true).
+*/
 time_t NTPClient::get_timestamp(int timeout) {
-    const time_t TIME1970 = (time_t)2208988800UL;
-    int ntp_send_values[12] = {0};
-    int ntp_recv_values[12] = {0};
-
-    SocketAddress nist;
-    int ret_gethostbyname = iface->gethostbyname(nist_server_address, &nist);
+	const time_t TIME1970 = (time_t)2208988800UL;
+	int ntp_send_values[12] = {0};
+	int ntp_recv_values[12] = {0};
 
-    if (ret_gethostbyname < 0) {
-        // Network error on DNS lookup
-        printf("Error on DNS lookup : %d\n" , ret_gethostbyname);
-        return ret_gethostbyname;
-    }
-
-    nist.set_port(nist_server_port);
+	SocketAddress nist;
+	UDPSocket sock;
+	SocketAddress source;
+	
+	nsapi_size_or_error_t szerr;
 
-    memset(ntp_send_values, 0x00, sizeof(ntp_send_values));
-    ntp_send_values[0] = '\x1b';
+	int ret_gethostbyname = iface->gethostbyname(nist_server_address, &nist);
+	if (ret_gethostbyname < 0) {
+		// Network error on DNS lookup
+		printf("Error on DNS lookup : %d\n" , ret_gethostbyname);
+		return ret_gethostbyname;
+	}
+	nist.set_port(nist_server_port);
 
-    memset(ntp_recv_values, 0x00, sizeof(ntp_recv_values));
+	memset(ntp_recv_values, 0x00, sizeof(ntp_recv_values));
+	memset(ntp_send_values, 0x00, sizeof(ntp_send_values));
+	ntp_send_values[0] = '\x1b';
 
-    UDPSocket sock;
-    sock.open(iface);
-    sock.set_timeout(timeout);
+	sock.open(iface);
+	sock.set_timeout(timeout);
+	
+	szerr = sock.sendto(nist, (void*)ntp_send_values, sizeof(ntp_send_values));
+	if(szerr < 0) {
+		sock.close();
+		printf("sock.sendto() error code = %d\n\r", szerr);
+		return szerr;
+	}
 
-    sock.sendto(nist, (void*)ntp_send_values, sizeof(ntp_send_values));
+    szerr = sock.recvfrom(&source, (void*)ntp_recv_values, sizeof(ntp_recv_values));
+	if(szerr < 0) {
+		sock.close();
+		printf("sock.sendto() error code = %d\n\r", szerr);
+		return szerr;
+	}
 
-    SocketAddress source;
-    const int n = sock.recvfrom(&source, (void*)ntp_recv_values, sizeof(ntp_recv_values));
-
-    if (n > 10) {
+    if (szerr > 10) {
         return ntohl(ntp_recv_values[10]) - TIME1970;
     } else {
-        if (n < 0) {
-            // Network error
-            printf("Network error: %d\n", n);
-            return n;
-        } else {
-            // No or partial data returned
-            printf("No or partial data returned: -1");
-            return -1;
-        }
-    }
+		// No or partial data returned
+		printf("No or partial data returned: bytes=%d\n\r", szerr);
+        return -1;
+	}
 }
 
 uint32_t NTPClient::ntohl(uint32_t x) {
@@ -61,4 +73,4 @@
     ret |= (x & 0xff0000UL) >> 8;
     ret |= (x & 0xff000000UL) >> 24;
     return ret;
-}
\ No newline at end of file
+}

--- a/NTPClient.h	Fri Dec 07 13:07:56 2018 +0000
+++ b/NTPClient.h	Sun May 26 08:46:35 2019 +0100
@@ -4,8 +4,7 @@
 #include "mbed.h"
 //use nslookup 2.pool.ntp.org in cmd to find ip address
 
-//#define NTP_DEFULT_NIST_SERVER_ADDRESS "2.pool.ntp.org"
-#define NTP_DEFULT_NIST_SERVER_ADDRESS "109.74.206.120"
+#define NTP_DEFULT_NIST_SERVER_ADDRESS "0.pool.ntp.org"
 #define NTP_DEFULT_NIST_SERVER_PORT 123
 
 class NTPClient {