android: Remove special handling of legacy Android versions in native code

Since minSdkVersion has been 21 for a while, we can remove some code
that was necessary for older versions.

src/frontends/android/app/src/main/jni/libandroidbridge/android_jni.h

@@ -48,17 +48,11 @@ extern jclass *android_charonvpnservice_builder_class;
 extern jclass *android_simple_fetcher_class;
 
 /**
- * Currently known (supported) SDK versions
+ * SDK versions for which we need some special handling.
  *
  * see android.os.Build.VERSION_CODES for definitions
  */
 typedef enum {
-	ANDROID_ICE_CREAM_SANDWICH = 14,
-	ANDROID_ICE_CREAM_SANDWICH_MR1 = 15,
-	ANDROID_JELLY_BEAN = 16,
-	ANDROID_JELLY_BEAN_MR1 = 17,
-	ANDROID_JELLY_BEAN_MR2 = 18,
-	ANDROID_LOLLIPOP = 21,
 	ANDROID_MARSHMALLOW = 23,
 } android_sdk_version_t;
 

src/frontends/android/app/src/main/jni/libandroidbridge/backend/android_private_key.c

@@ -435,16 +435,7 @@ METHOD(private_key_t, destroy, void,
 		JNIEnv *env;
 
 		androidjni_attach_thread(&env);
-		if (android_sdk_version == ANDROID_JELLY_BEAN)
+		(*env)->DeleteGlobalRef(env, this->key);
-		{	/* there is a bug in JB that causes a SIGSEGV if the key object is
-			 * garbage collected so we intentionally leak the reference to it */
-			DBG1(DBG_LIB, "intentionally leaking private key reference due to "
-				 "a bug in the framework");
-		}
-		else
-		{
-			(*env)->DeleteGlobalRef(env, this->key);
-		}
 		(*env)->DeleteGlobalRef(env, this->signature_class);
 		androidjni_detach_thread();
 		this->pubkey->destroy(this->pubkey);

src/frontends/android/app/src/main/jni/libandroidbridge/backend/android_service.c

@@ -792,10 +792,9 @@ static job_requeue_t initiate(private_android_service_t *this)
 	};
 	char *type, *remote_id;
 
-	if (android_sdk_version >= ANDROID_LOLLIPOP)
+	/* only try once and notify the GUI since Android 5+ where we have a
-	{   /* only try once and notify the GUI on Android 5+ where we have a blocking TUN device */
+	 * blocking TUN device */
-		peer.keyingtries = 1;
+	peer.keyingtries = 1;
-	}
 
 	ike.remote = this->settings->get_str(this->settings, "connection.server",
 										 NULL);

src/frontends/android/app/src/main/jni/libandroidbridge/kernel/android_net.c

@@ -124,11 +124,6 @@ METHOD(kernel_net_t, get_source_addr, host_t*,
 	}
 	charonservice->bypass_socket(charonservice, skt, dst->get_family(dst));
 
-	if (android_sdk_version <= ANDROID_JELLY_BEAN_MR2)
-	{	/* this seems to help avoiding the VIP, unless there is no connectivity
-		 * at all */
-		charonservice->bypass_socket(charonservice, -1, 0);
-	}
 	if (connect(skt, dst->get_sockaddr(dst), addrlen) < 0)
 	{
 		/* don't report an error if we are not connected (ENETUNREACH) */
@@ -179,28 +174,6 @@ CALLBACK(vip_equals, bool,
 	return host->ip_equals(host, vip);
 }
 
-METHOD(kernel_net_t, get_source_addr_old, host_t*,
-	private_android_net_t *this, host_t *dest, host_t *src)
-{
-	host_t *host;
-
-	/* on older Android versions we might get the virtual IP back because
-	 * the protect() implementation there and connect() don't properly work
-	 * together, on newer releases (using fwmarks) that's not a problem */
-	host = get_source_addr(this, dest, src);
-	if (host)
-	{
-		this->mutex->lock(this->mutex);
-		if (this->vips->find_first(this->vips, vip_equals, NULL, host))
-		{
-			host->destroy(host);
-			host = NULL;
-		}
-		this->mutex->unlock(this->mutex);
-	}
-	return host;
-}
-
 METHOD(kernel_net_t, get_nexthop, host_t*,
 	private_android_net_t *this, host_t *dest, int prefix, host_t *src,
 	char **iface)
@@ -303,11 +276,6 @@ kernel_net_t *kernel_android_net_create()
 	);
 	timerclear(&this->next_roam);
 
-	if (android_sdk_version <= ANDROID_JELLY_BEAN_MR2)
-	{
-		this->public.get_source_addr = _get_source_addr_old;
-	}
-
 	this->mutex->lock(this->mutex);
 	this->network_manager->add_connectivity_cb(
 						this->network_manager, (void*)connectivity_cb, this);