diff options
| -rw-r--r-- | core/java/android/util/NtpTrustedTime.java | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/core/java/android/util/NtpTrustedTime.java b/core/java/android/util/NtpTrustedTime.java index 01a037ae3495..4e7b3a51d758 100644 --- a/core/java/android/util/NtpTrustedTime.java +++ b/core/java/android/util/NtpTrustedTime.java @@ -193,6 +193,16 @@ public class NtpTrustedTime implements TrustedTime { } final Network network = connectivityManager.getActiveNetwork(); final NetworkInfo ni = connectivityManager.getNetworkInfo(network); + + // This connectivity check is to avoid performing a DNS lookup for the time server on a + // unconnected network. There are races to obtain time in Android when connectivity + // changes, which means that forceRefresh() can be called by various components before + // the network is actually available. This led in the past to DNS lookup failures being + // cached (~2 seconds) thereby preventing the device successfully making an NTP request + // when connectivity had actually been established. + // A side effect of check is that tests that run a fake NTP server on the device itself + // will only be able to use it if the active network is connected, even though loopback + // addresses are actually reachable. if (ni == null || !ni.isConnected()) { if (LOGD) Log.d(TAG, "forceRefresh: no connectivity"); return false; |