Adding retries to the NIST test.

A UDP request to the NIST servers can fail to return data due to UDP
packet loss. Since packets are not guaranteed with UDP, this is a valid
failure and should not be treated as a test failure. The test should retry
the request in this case. This commit adds those retries.

Author: bridadan

features/net/FEATURE_IPV4/TESTS/mbedmicro-net/nist_internet_time_service/main.cpp

@@ -8,55 +8,64 @@
 #include "greentea-client/test_env.h"
 
 namespace {
-    //const char *HTTP_SERVER_NAME = "utcnist.colorado.edu";
     const char *HTTP_SERVER_NAME = "pool.ntp.org";
     const int HTTP_SERVER_PORT = 123;
 }
 
 
 int main() {
-    GREENTEA_SETUP(20, "default_auto");
+    GREENTEA_SETUP(60, "default_auto");
 
     bool result = false;
     const time_t TIME1970 = 2208988800L;
-    int ntp_values[12] = {0};
+    int ntp_send_values[12] = {0};
+    int ntp_recv_values[12] = {0};
 
     EthernetInterface eth;
-    //eth.init(); //Use DHCP
     eth.connect();
     printf("UDP client IP Address is %s\n", eth.get_ip_address());
 
     UDPSocket sock;
     sock.open(&eth);
+    sock.set_timeout(15000);
 
     SocketAddress nist(&eth, HTTP_SERVER_NAME, HTTP_SERVER_PORT);
 
     printf("UDP: NIST server %s address: %s on port %d\r\n", HTTP_SERVER_NAME, nist.get_ip_address(), nist.get_port());
 
-    memset(ntp_values, 0x00, sizeof(ntp_values));
-    ntp_values[0] = '\x1b';
+    memset(ntp_send_values, 0x00, sizeof(ntp_send_values));
+    ntp_send_values[0] = '\x1b';
 
-    int ret_send = sock.sendto(nist, (void*)ntp_values, sizeof(ntp_values));
-    printf("UDP: Sent %d Bytes to NTP server \n", ret_send);
+    while(1) {
+        memset(ntp_recv_values, 0x00, sizeof(ntp_recv_values));
 
-    const int n = sock.recvfrom(&nist, (void*)ntp_values, sizeof(ntp_values));
+        int ret_send = sock.sendto(nist, (void*)ntp_send_values, sizeof(ntp_send_values));
+        printf("UDP: Sent %d Bytes to NTP server \n", ret_send);
 
-    printf("UDP: Recved from NTP server %d Bytes \n", n);
+        const int n = sock.recvfrom(&nist, (void*)ntp_recv_values, sizeof(ntp_recv_values));
 
-    if (n > 0 ) {
-        result = true;
+        printf("UDP: Recved from NTP server %d Bytes \n", n);
 
-        printf("UDP: Values returned by NTP server: \n");
-        for (size_t i=0; i < sizeof(ntp_values) / sizeof(ntp_values[0]); ++i) {
-            printf("\t[%02d] 0x%X", i, ntohl(ntp_values[i]));
+        if (n > 0) {
+            result = true;
 
-            if (i == 10) {
-                time_t timestamp = ntohl(ntp_values[i]) - TIME1970;
-                printf("\tNTP timestamp is %s", ctime(&timestamp));
-            } else {
-                printf("\n");
+            printf("UDP: Values returned by NTP server: \n");
+            for (size_t i=0; i < sizeof(ntp_recv_values) / sizeof(ntp_recv_values[0]); ++i) {
+                printf("\t[%02d] 0x%X", i, ntohl(ntp_recv_values[i]));
+
+                if (i == 10) {
+                    time_t timestamp = ntohl(ntp_recv_values[i]) - TIME1970;
+                    printf("\tNTP timestamp is %s", ctime(&timestamp));
+                } else {
+                    printf("\n");
+                }
             }
+
+            break;
         }
+
+        printf("Failed to receive data, retrying in 5 seconds...\n");
+        wait(5);
     }
 
     sock.close();