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Commit 94887874 authored by Erik Kline's avatar Erik Kline
Browse files

Don't flush DNS cache on route changes. 

Since Lollipop, routes are isolated within Networks.  Flushing a
Network's DNS cache whenever that same Network's routes are updated
doesn't provide any benefit.  Any system components depending on this
behaviour need to uncovered and fixed.

Additionally, clean up no-longer-used flushNetworkDnsCache().  This
should be replaced, when needed, by a proper binder interface to netd.

Change-Id: I34bf79e4839da014d466058a876d754209d0c007
parent 49e2db1b

core/java/android/os/INetworkManagementService.aidl

+0 −5
Original line number Diff line number Diff line
@@ -328,11 +328,6 @@ interface INetworkManagementService 
     */

    void setDnsServersForNetwork(int netId, in String[] servers, String domains);



    /**

     * Flush the DNS cache associated with the specified network.

     */

    void flushNetworkDnsCache(int netId);



    void setFirewallEnabled(boolean enabled);

    boolean isFirewallEnabled();

    void setFirewallInterfaceRule(String iface, boolean allow);

services/core/java/com/android/server/ConnectivityService.java

+19 −25
Original line number Diff line number Diff line
@@ -4134,8 +4134,8 @@ public class ConnectivityService extends IConnectivityManager.Stub 
//        }

        updateTcpBufferSizes(networkAgent);



        final boolean flushDns = updateRoutes(newLp, oldLp, netId);

        updateDnses(newLp, oldLp, netId, flushDns);

        updateRoutes(newLp, oldLp, netId);

        updateDnses(newLp, oldLp, netId);



        updateClat(newLp, oldLp, networkAgent);

        if (isDefaultNetwork(networkAgent)) {
@@ -4238,14 +4238,16 @@ public class ConnectivityService extends IConnectivityManager.Stub 
        return !routeDiff.added.isEmpty() || !routeDiff.removed.isEmpty();

    }



    private void updateDnses(LinkProperties newLp, LinkProperties oldLp, int netId,

                             boolean flush) {

        if (oldLp == null || (newLp.isIdenticalDnses(oldLp) == false)) {

    private void updateDnses(LinkProperties newLp, LinkProperties oldLp, int netId) {

        if (oldLp != null && newLp.isIdenticalDnses(oldLp)) {

            return;  // no updating necessary

        }



        Collection<InetAddress> dnses = newLp.getDnsServers();

        if (DBG) log("Setting Dns servers for network " + netId + " to " + dnses);

        try {

                mNetd.setDnsServersForNetwork(netId, NetworkUtils.makeStrings(dnses),

                    newLp.getDomains());

            mNetd.setDnsServersForNetwork(

                    netId, NetworkUtils.makeStrings(dnses), newLp.getDomains());

        } catch (Exception e) {

            loge("Exception in setDnsServersForNetwork: " + e);

        }
@@ -4254,14 +4256,6 @@ public class ConnectivityService extends IConnectivityManager.Stub 
            setDefaultDnsSystemProperties(dnses);

        }

        flushVmDnsCache();

        } else if (flush) {

            try {

                mNetd.flushNetworkDnsCache(netId);

            } catch (Exception e) {

                loge("Exception in flushNetworkDnsCache: " + e);

            }

            flushVmDnsCache();

        }

    }



    private void setDefaultDnsSystemProperties(Collection<InetAddress> dnses) {

services/core/java/com/android/server/NetworkManagementService.java

+0 −10
Original line number Diff line number Diff line
@@ -1936,16 +1936,6 @@ public class NetworkManagementService extends INetworkManagementService.Stub 
        }

    }



    @Override

    public void flushNetworkDnsCache(int netId) {

        mContext.enforceCallingOrSelfPermission(CONNECTIVITY_INTERNAL, TAG);

        try {

            mConnector.execute("resolver", "flushnet", netId);

        } catch (NativeDaemonConnectorException e) {

            throw e.rethrowAsParcelableException();

        }

    }



    @Override

    public void setFirewallEnabled(boolean enabled) {

        enforceSystemUid();