1 files changed, 12 insertions, 1 deletions
diff --git a/app/src/main/java/se/leap/bitmaskclient/base/utils/ConfigHelper.java b/app/src/main/java/se/leap/bitmaskclient/base/utils/ConfigHelper.java
index 4248072a..005a8b82 100644
--- a/app/src/main/java/se/leap/bitmaskclient/base/utils/ConfigHelper.java
+++ b/app/src/main/java/se/leap/bitmaskclient/base/utils/ConfigHelper.java
@@ -44,10 +44,12 @@ import java.security.interfaces.RSAPrivateKey;
 import java.security.spec.InvalidKeySpecException;
 import java.security.spec.PKCS8EncodedKeySpec;
 import java.util.Calendar;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 import se.leap.bitmaskclient.BuildConfig;
-import se.leap.bitmaskclient.providersetup.ProviderAPI;
 import se.leap.bitmaskclient.R;
+import se.leap.bitmaskclient.providersetup.ProviderAPI;
 
 import static se.leap.bitmaskclient.base.models.Constants.DEFAULT_BITMASK;
 
@@ -62,6 +64,7 @@ public class ConfigHelper {
     final public static String NG_1024 =
             "eeaf0ab9adb38dd69c33f80afa8fc5e86072618775ff3c0b9ea2314c9c256576d674df7496ea81d3383b4813d692c6e0e0d5d8e250b98be48e495c1d6089dad15dc7d7b46154d6b6ce8ef4ad69b15d4982559b297bcf1885c529f566660e57ec68edbc3c05726cc02fd4cbf4976eaa9afd5138fe8376435b9fc61d2fc0eb06e3";
     final public static BigInteger G = new BigInteger("2");
+    final public static Pattern IPv4_PATTERN = Pattern.compile("^(?:(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9])\\.){3}(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9])$");
 
     public static boolean checkErroneousDownload(String downloadedString) {
         try {
@@ -227,4 +230,12 @@ public class ConfigHelper {
         }
     }
 
+    public static boolean isIPv4(String ipv4) {
+        if (ipv4 == null) {
+            return false;
+        }
+        Matcher matcher = IPv4_PATTERN.matcher(ipv4);
+        return matcher.matches();
+    }
+
 }