c-ares

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Author	SHA1	Message	Date
John Schember	1abf13ed30	Fix DNS server lookup breaking with Android O due to Android removing access to net.dns# system properties. (#148 ) As of Android 8 (Oreo) access to net.dns# has been removed (https://developer.android.com/about/versions/oreo/android-8.0-changes.html). The reasoning given is that it, "improves privacy on the platform". Currently c-ares uses this to get the list of DNS servers. Now the only way to access the DNS server list is by using the Connectivity Manager though Java. This adds the necessary JNI code to use the Connectivity Manager and pull the DNS server list. The old way using __system_property_get with net.dns# remains for compatibilty. Using the Connectivity Manager requires the ACCESS_NETWORK_STATE permission to be set on the app. Existing applications most likely are not setting this and keeping the previous method as a fallback will at the very least ensure those apps don't break on older versions of Android. They will need to add this permission for Android 8 compatibility. Included in the patch are two initalization functions which are required. The JVM must be registered as well as the Connectivity Manager itself. There is no way to get the Connectivity Manager except though Java. Either being passed down to C directly or by passing in an Android Context which can be used to get the Connectivity Manager. Examples are provided in the documentation.	7 years ago

Author

SHA1

Message

Date

John Schember

1abf13ed30

Fix DNS server lookup breaking with Android O due to Android removing access to net.dns# system properties. (#148 )

As of Android 8 (Oreo) access to net.dns# has been removed (https://developer.android.com/about/versions/oreo/android-8.0-changes.html). The reasoning given is that it, "improves privacy on the platform". Currently c-ares uses this to get the list of DNS servers.

Now the only way to access the DNS server list is by using the Connectivity Manager though Java. This adds the necessary JNI code to use the Connectivity Manager and pull the DNS server list. The old way using __system_property_get with net.dns# remains for compatibilty.

Using the Connectivity Manager requires the ACCESS_NETWORK_STATE permission to be set on the app. Existing applications most likely are not setting this and keeping the previous method as a fallback will at the very least ensure those apps don't break on older versions of Android. They will need to add this permission for Android 8 compatibility.

Included in the patch are two initalization functions which are required. The JVM must be registered as well as the Connectivity Manager itself. There is no way to get the Connectivity Manager except though Java. Either being passed down to C directly or by passing in an Android Context which can be used to get the Connectivity Manager. Examples are provided in the documentation.

7 years ago

1 Commits (b980d53eedf5d1422cc29353beea03056344caa9)