android: Add method to BuilderAdapter to re-establish without DNS-related data

Non-DNS data is cached in the BuilderAdapter so the TUN device can be
recreated easily (since the CHILD_SA is gone we couldn't actually gather
that information).

src/frontends/android/jni/libandroidbridge/vpnservice_builder.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2012-2013 Tobias Brunner
+ * Copyright (C) 2012-2014 Tobias Brunner
  * Copyright (C) 2012 Giuliano Grassi
  * Copyright (C) 2012 Ralf Sager
  * Hochschule fuer Technik Rapperswil
@@ -197,8 +197,10 @@ failed:
 	return FALSE;
 }
 
-METHOD(vpnservice_builder_t, establish, int,
-	private_vpnservice_builder_t *this)
+/**
+ * Establish or reestablish the TUN device
+ */
+static int establish_internal(private_vpnservice_builder_t *this, char *method)
 {
 	JNIEnv *env;
 	jmethodID method_id;
@@ -209,7 +211,7 @@ METHOD(vpnservice_builder_t, establish, int,
 	DBG2(DBG_LIB, "builder: building TUN device");
 
 	method_id = (*env)->GetMethodID(env, android_charonvpnservice_builder_class,
-									"establish", "()I");
+									method, "()I");
 	if (!method_id)
 	{
 		goto failed;
@@ -229,6 +231,18 @@ failed:
 	return -1;
 }
 
+METHOD(vpnservice_builder_t, establish, int,
+	private_vpnservice_builder_t *this)
+{
+	return establish_internal(this, "establish");
+}
+
+METHOD(vpnservice_builder_t, establish_no_dns, int,
+	private_vpnservice_builder_t *this)
+{
+	return establish_internal(this, "establishNoDns");
+}
+
 METHOD(vpnservice_builder_t, destroy, void,
 	private_vpnservice_builder_t *this)
 {
@@ -252,6 +266,7 @@ vpnservice_builder_t *vpnservice_builder_create(jobject builder)
 			.add_dns = _add_dns,
 			.set_mtu = _set_mtu,
 			.establish = _establish,
+			.establish_no_dns = _establish_no_dns,
 			.destroy = _destroy,
 		},
 	);

src/frontends/android/jni/libandroidbridge/vpnservice_builder.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2012 Tobias Brunner
+ * Copyright (C) 2012-2014 Tobias Brunner
  * Copyright (C) 2012 Giuliano Grassi
  * Copyright (C) 2012 Ralf Sager
  * Hochschule fuer Technik Rapperswil
@@ -77,6 +77,13 @@ struct vpnservice_builder_t {
 	 */
 	int (*establish)(vpnservice_builder_t *this);
 
+	/**
+	 * Build the TUN device without DNS related data
+	 *
+	 * @return					the TUN file descriptor, -1 if failed
+	 */
+	int (*establish_no_dns)(vpnservice_builder_t *this);
+
 	/**
 	 * Destroy a vpnservice_builder
 	 */

src/frontends/android/src/org/strongswan/android/logic/CharonVpnService.java

@@ -22,6 +22,7 @@ import java.security.PrivateKey;
 import java.security.cert.CertificateEncodingException;
 import java.security.cert.X509Certificate;
 import java.util.ArrayList;
+import java.util.List;
 
 import org.strongswan.android.data.VpnProfile;
 import org.strongswan.android.data.VpnProfileDataSource;
@@ -526,11 +527,14 @@ public class CharonVpnService extends VpnService implements Runnable
 	{
 		private final String mName;
 		private VpnService.Builder mBuilder;
+		private BuilderCache mCache;
+		private BuilderCache mEstablishedCache;
 
 		public BuilderAdapter(String name)
 		{
 			mName = name;
 			mBuilder = createBuilder(name);
+			mCache = new BuilderCache();
 		}
 
 		private VpnService.Builder createBuilder(String name)
@@ -553,6 +557,7 @@ public class CharonVpnService extends VpnService implements Runnable
 			try
 			{
 				mBuilder.addAddress(address, prefixLength);
+				mCache.addAddress(address, prefixLength);
 			}
 			catch (IllegalArgumentException ex)
 			{
@@ -579,6 +584,7 @@ public class CharonVpnService extends VpnService implements Runnable
 			try
 			{
 				mBuilder.addRoute(address, prefixLength);
+				mCache.addRoute(address, prefixLength);
 			}
 			catch (IllegalArgumentException ex)
 			{
@@ -605,6 +611,7 @@ public class CharonVpnService extends VpnService implements Runnable
 			try
 			{
 				mBuilder.setMtu(mtu);
+				mCache.setMtu(mtu);
 			}
 			catch (IllegalArgumentException ex)
 			{
@@ -632,8 +639,87 @@ public class CharonVpnService extends VpnService implements Runnable
 			/* now that the TUN device is created we don't need the current
 			 * builder anymore, but we might need another when reestablishing */
 			mBuilder = createBuilder(mName);
+			mEstablishedCache = mCache;
+			mCache = new BuilderCache();
 			return fd.detachFd();
 		}
+
+		public synchronized int establishNoDns()
+		{
+			ParcelFileDescriptor fd;
+
+			if (mEstablishedCache == null)
+			{
+				return -1;
+			}
+			try
+			{
+				Builder builder = createBuilder(mName);
+				mEstablishedCache.applyData(builder);
+				fd = builder.establish();
+			}
+			catch (Exception ex)
+			{
+				ex.printStackTrace();
+				return -1;
+			}
+			if (fd == null)
+			{
+				return -1;
+			}
+			return fd.detachFd();
+		}
+	}
+
+	/**
+	 * Cache non DNS related information so we can recreate the builder without
+	 * that information when reestablishing IKE_SAs
+	 */
+	public class BuilderCache
+	{
+		private final List<PrefixedAddress> mAddresses = new ArrayList<PrefixedAddress>();
+		private final List<PrefixedAddress> mRoutes = new ArrayList<PrefixedAddress>();
+		private int mMtu;
+
+		public void addAddress(String address, int prefixLength)
+		{
+			mAddresses.add(new PrefixedAddress(address, prefixLength));
+		}
+
+		public void addRoute(String address, int prefixLength)
+		{
+			mRoutes.add(new PrefixedAddress(address, prefixLength));
+		}
+
+		public void setMtu(int mtu)
+		{
+			mMtu = mtu;
+		}
+
+		public void applyData(VpnService.Builder builder)
+		{
+			for (PrefixedAddress address : mAddresses)
+			{
+				builder.addAddress(address.mAddress, address.mPrefix);
+			}
+			for (PrefixedAddress route : mRoutes)
+			{
+				builder.addRoute(route.mAddress, route.mPrefix);
+			}
+			builder.setMtu(mMtu);
+		}
+
+		private class PrefixedAddress
+		{
+			public String mAddress;
+			public int mPrefix;
+
+			public PrefixedAddress(String address, int prefix)
+			{
+				this.mAddress = address;
+				this.mPrefix = prefix;
+			}
+		}
 	}
 
 	/*