Second pass tying into dns cache per interface

Set dns servers for secondary nets and attach the
processes (pids) that are using the secondary nets
to the secondary nets associated dns cache.

bug:5465296
Change-Id: I1eaf92d5c6b81d287e9fb2763b3d972d9de34395

3 files changed, 79 insertions, 114 deletions

diff --git a/core/java/android/os/INetworkManagementService.aidl b/core/java/android/os/INetworkManagementService.aidl
index d0e501910f60..c765457fe708 100644
--- a/core/java/android/os/INetworkManagementService.aidl
+++ b/core/java/android/os/INetworkManagementService.aidl
@@ -352,4 +352,14 @@ interface INetworkManagementService
     void setFirewallEgressSourceRule(String addr, boolean allow);
     void setFirewallEgressDestRule(String addr, int port, boolean allow);
     void setFirewallUidRule(int uid, boolean allow);
+
+    /**
+     * Set a process (pid) to use the name servers associated with the specified interface.
+     */
+    void setDnsInterfaceForPid(String iface, int pid);
+
+    /**
+     * Clear a process (pid) from being associated with an interface.
+     */
+    void clearDnsInterfaceForPid(int pid);
 }
diff --git a/services/java/com/android/server/ConnectivityService.java b/services/java/com/android/server/ConnectivityService.java
index 7cfa8c266763..8e21246c19db 100644
--- a/services/java/com/android/server/ConnectivityService.java
+++ b/services/java/com/android/server/ConnectivityService.java
@@ -183,7 +183,7 @@ public class ConnectivityService extends IConnectivityManager.Stub {
      * A per Net list of the PID's that requested access to the net
      * used both as a refcount and for per-PID DNS selection
      */
-    private List mNetRequestersPids[];
+    private List<Integer> mNetRequestersPids[];
 
     // priority order of the nettrackers
     // (excluding dynamically set mNetworkPreference)
@@ -199,7 +199,6 @@ public class ConnectivityService extends IConnectivityManager.Stub {
     private int mDefaultConnectionSequence = 0;
 
     private Object mDnsLock = new Object();
-    private int mNumDnsEntries;
     private boolean mDnsOverridden = false;
 
     private boolean mTestMode;
@@ -507,15 +506,14 @@ public class ConnectivityService extends IConnectivityManager.Stub {
             }
         }
 
-        mNetRequestersPids = new ArrayList[ConnectivityManager.MAX_NETWORK_TYPE+1];
+        mNetRequestersPids =
+                (List<Integer> [])new ArrayList[ConnectivityManager.MAX_NETWORK_TYPE+1];
         for (int i : mPriorityList) {
-            mNetRequestersPids[i] = new ArrayList();
+            mNetRequestersPids[i] = new ArrayList<Integer>();
         }
 
         mFeatureUsers = new ArrayList<FeatureUser>();
 
-        mNumDnsEntries = 0;
-
         mTestMode = SystemProperties.get("cm.test.mode").equals("true")
                 && SystemProperties.get("ro.build.type").equals("eng");
 
@@ -1316,6 +1314,7 @@ public class ConnectivityService extends IConnectivityManager.Stub {
                 Integer currentPid = new Integer(pid);
                 mNetRequestersPids[usedNetworkType].remove(currentPid);
                 reassessPidDns(pid, true);
+                flushVmDnsCache();
                 if (mNetRequestersPids[usedNetworkType].size() != 0) {
                     if (VDBG) {
                         log("stopUsingNetworkFeature: net " + networkType + ": " + feature +
@@ -1697,9 +1696,8 @@ public class ConnectivityService extends IConnectivityManager.Stub {
          * in accordance with network preference policies.
          */
         if (!mNetConfigs[prevNetType].isDefault()) {
-            List pids = mNetRequestersPids[prevNetType];
-            for (int i = 0; i<pids.size(); i++) {
-                Integer pid = (Integer)pids.get(i);
+            List<Integer> pids = mNetRequestersPids[prevNetType];
+            for (Integer pid : pids) {
                 // will remove them because the net's no longer connected
                 // need to do this now as only now do we know the pids and
                 // can properly null things that are no longer referenced.
@@ -2261,6 +2259,7 @@ public class ConnectivityService extends IConnectivityManager.Stub {
                         }
                     }
                     if (resetDns) {
+                        flushVmDnsCache();
                         if (VDBG) log("resetting DNS cache for " + iface);
                         try {
                             mNetd.flushInterfaceDnsCache(iface);
@@ -2427,9 +2426,10 @@ public class ConnectivityService extends IConnectivityManager.Stub {
      * on the highest priority active net which this process requested.
      * If there aren't any, clear it out
      */
-    private void reassessPidDns(int myPid, boolean doBump)
+    private void reassessPidDns(int pid, boolean doBump)
     {
-        if (VDBG) log("reassessPidDns for pid " + myPid);
+        if (VDBG) log("reassessPidDns for pid " + pid);
+        Integer myPid = new Integer(pid);
         for(int i : mPriorityList) {
             if (mNetConfigs[i].isDefault()) {
                 continue;
@@ -2439,61 +2439,25 @@ public class ConnectivityService extends IConnectivityManager.Stub {
                     !nt.isTeardownRequested()) {
                 LinkProperties p = nt.getLinkProperties();
                 if (p == null) continue;
-                List pids = mNetRequestersPids[i];
-                for (int j=0; j<pids.size(); j++) {
-                    Integer pid = (Integer)pids.get(j);
-                    if (pid.intValue() == myPid) {
-                        Collection<InetAddress> dnses = p.getDnses();
-                        writePidDns(dnses, myPid);
-                        if (doBump) {
-                            bumpDns();
-                        }
-                        return;
+                if (mNetRequestersPids[i].contains(myPid)) {
+                    try {
+                        mNetd.setDnsInterfaceForPid(p.getInterfaceName(), pid);
+                    } catch (Exception e) {
+                        Slog.e(TAG, "exception reasseses pid dns: " + e);
                     }
+                    return;
                 }
            }
         }
         // nothing found - delete
-        for (int i = 1; ; i++) {
-            String prop = "net.dns" + i + "." + myPid;
-            if (SystemProperties.get(prop).length() == 0) {
-                if (doBump) {
-                    bumpDns();
-                }
-                return;
-            }
-            SystemProperties.set(prop, "");
-        }
-    }
-
-    // return true if results in a change
-    private boolean writePidDns(Collection <InetAddress> dnses, int pid) {
-        int j = 1;
-        boolean changed = false;
-        for (InetAddress dns : dnses) {
-            String dnsString = dns.getHostAddress();
-            if (changed || !dnsString.equals(SystemProperties.get("net.dns" + j + "." + pid))) {
-                changed = true;
-                SystemProperties.set("net.dns" + j + "." + pid, dns.getHostAddress());
-            }
-            j++;
+        try {
+            mNetd.clearDnsInterfaceForPid(pid);
+        } catch (Exception e) {
+            Slog.e(TAG, "exception clear interface from pid: " + e);
         }
-        return changed;
     }
 
-    private void bumpDns() {
-        /*
-         * Bump the property that tells the name resolver library to reread
-         * the DNS server list from the properties.
-         */
-        String propVal = SystemProperties.get("net.dnschange");
-        int n = 0;
-        if (propVal.length() != 0) {
-            try {
-                n = Integer.parseInt(propVal);
-            } catch (NumberFormatException e) {}
-        }
-        SystemProperties.set("net.dnschange", "" + (n+1));
+    private void flushVmDnsCache() {
         /*
          * Tell the VMs to toss their DNS caches
          */
@@ -2512,56 +2476,23 @@ public class ConnectivityService extends IConnectivityManager.Stub {
     }
 
     // Caller must grab mDnsLock.
-    private boolean updateDns(String network, String iface,
+    private void updateDnsLocked(String network, String iface,
             Collection<InetAddress> dnses, String domains) {
-        boolean changed = false;
         int last = 0;
         if (dnses.size() == 0 && mDefaultDns != null) {
-            ++last;
-            String value = mDefaultDns.getHostAddress();
-            if (!value.equals(SystemProperties.get("net.dns1"))) {
-                if (DBG) {
-                    loge("no dns provided for " + network + " - using " + value);
-                }
-                changed = true;
-                SystemProperties.set("net.dns1", value);
-            }
-        } else {
-            for (InetAddress dns : dnses) {
-                ++last;
-                String key = "net.dns" + last;
-                String value = dns.getHostAddress();
-                if (!changed && value.equals(SystemProperties.get(key))) {
-                    continue;
-                }
-                if (VDBG) {
-                    log("adding dns " + value + " for " + network);
-                }
-                changed = true;
-                SystemProperties.set(key, value);
+            dnses = new ArrayList();
+            dnses.add(mDefaultDns);
+            if (DBG) {
+                loge("no dns provided for " + network + " - using " + mDefaultDns.getHostAddress());
             }
         }
-        for (int i = last + 1; i <= mNumDnsEntries; ++i) {
-            String key = "net.dns" + i;
-            if (VDBG) log("erasing " + key);
-            changed = true;
-            SystemProperties.set(key, "");
-        }
-        mNumDnsEntries = last;
-        if (SystemProperties.get("net.dns.search").equals(domains) == false) {
-            SystemProperties.set("net.dns.search", domains);
-            changed = true;
-        }
 
-        if (changed) {
-            try {
-                mNetd.setDnsServersForInterface(iface, NetworkUtils.makeStrings(dnses), domains);
-                mNetd.setDefaultInterfaceForDns(iface);
-            } catch (Exception e) {
-                if (DBG) loge("exception setting default dns interface: " + e);
-            }
+        try {
+            mNetd.setDnsServersForInterface(iface, NetworkUtils.makeStrings(dnses), domains);
+            mNetd.setDefaultInterfaceForDns(iface);
+        } catch (Exception e) {
+            if (DBG) loge("exception setting default dns interface: " + e);
         }
-        return changed;
     }
 
     private void handleDnsConfigurationChange(int netType) {
@@ -2571,12 +2502,11 @@ public class ConnectivityService extends IConnectivityManager.Stub {
             LinkProperties p = nt.getLinkProperties();
             if (p == null) return;
             Collection<InetAddress> dnses = p.getDnses();
-            boolean changed = false;
             if (mNetConfigs[netType].isDefault()) {
                 String network = nt.getNetworkInfo().getTypeName();
                 synchronized (mDnsLock) {
                     if (!mDnsOverridden) {
-                        changed = updateDns(network, p.getInterfaceName(), dnses, p.getDomains());
+                        updateDnsLocked(network, p.getInterfaceName(), dnses, p.getDomains());
                     }
                 }
             } else {
@@ -2587,13 +2517,16 @@ public class ConnectivityService extends IConnectivityManager.Stub {
                     if (DBG) loge("exception setting dns servers: " + e);
                 }
                 // set per-pid dns for attached secondary nets
-                List pids = mNetRequestersPids[netType];
-                for (int y=0; y< pids.size(); y++) {
-                    Integer pid = (Integer)pids.get(y);
-                    changed = writePidDns(dnses, pid.intValue());
+                List<Integer> pids = mNetRequestersPids[netType];
+                for (Integer pid : pids) {
+                    try {
+                        mNetd.setDnsInterfaceForPid(p.getInterfaceName(), pid);
+                    } catch (Exception e) {
+                        Slog.e(TAG, "exception setting interface for pid: " + e);
+                    }
                 }
             }
-            if (changed) bumpDns();
+            flushVmDnsCache();
         }
     }
 
@@ -2652,7 +2585,7 @@ public class ConnectivityService extends IConnectivityManager.Stub {
         pw.increaseIndent();
         for (int net : mPriorityList) {
             String pidString = net + ": ";
-            for (Object pid : mNetRequestersPids[net]) {
+            for (Integer pid : mNetRequestersPids[net]) {
                 pidString = pidString + pid.toString() + ", ";
             }
             pw.println(pidString);
@@ -3354,14 +3287,10 @@ public class ConnectivityService extends IConnectivityManager.Stub {
             String domains = buffer.toString().trim();
 
             // Apply DNS changes.
-            boolean changed = false;
             synchronized (mDnsLock) {
-                changed = updateDns("VPN", "VPN", addresses, domains);
+                updateDnsLocked("VPN", "VPN", addresses, domains);
                 mDnsOverridden = true;
             }
-            if (changed) {
-                bumpDns();
-            }
 
             // Temporarily disable the default proxy.
             synchronized (mDefaultProxyLock) {
diff --git a/services/java/com/android/server/NetworkManagementService.java b/services/java/com/android/server/NetworkManagementService.java
index 0a5459380372..2b0d8243a7ee 100644
--- a/services/java/com/android/server/NetworkManagementService.java
+++ b/services/java/com/android/server/NetworkManagementService.java
@@ -1468,6 +1468,32 @@ public class NetworkManagementService extends INetworkManagementService.Stub
     }
 
     @Override
+    public void setDnsInterfaceForPid(String iface, int pid) throws IllegalStateException {
+        mContext.enforceCallingOrSelfPermission(CONNECTIVITY_INTERNAL, TAG);
+        try {
+            String cmd = "resolver setifaceforpid " + iface + " " + pid;
+
+            mConnector.execute(cmd);
+        } catch (NativeDaemonConnectorException e) {
+            throw new IllegalStateException(
+                    "Error communicating with native deamon to set interface for pid" + iface, e);
+        }
+    }
+
+    @Override
+    public void clearDnsInterfaceForPid(int pid) throws IllegalStateException {
+        mContext.enforceCallingOrSelfPermission(CONNECTIVITY_INTERNAL, TAG);
+        try {
+            String cmd = "resolver clearifaceforpid " + pid;
+
+            mConnector.execute(cmd);
+        } catch (NativeDaemonConnectorException e) {
+            throw new IllegalStateException(
+                    "Error communicating with native deamon to clear interface for pid " + pid, e);
+        }
+    }
+
+    /** {@inheritDoc} */
     public void monitor() {
         if (mConnector != null) {
             mConnector.monitor();