Don't display duplicate push messages.

library/src/org/whispersystems/textsecure/crypto/DuplicateMessageException.java

@@ -0,0 +1,7 @@
+package org.whispersystems.textsecure.crypto;
+
+public class DuplicateMessageException extends Exception {
+  public DuplicateMessageException(String s) {
+    super(s);
+  }
+}

library/src/org/whispersystems/textsecure/crypto/SessionCipher.java

@@ -29,7 +29,7 @@ public abstract class SessionCipher {
   protected static final Object SESSION_LOCK = new Object();
 
   public abstract CiphertextMessage encrypt(byte[] paddedMessage);
-  public abstract byte[] decrypt(byte[] decodedMessage) throws InvalidMessageException;
+  public abstract byte[] decrypt(byte[] decodedMessage) throws InvalidMessageException, DuplicateMessageException;
   public abstract int getRemoteRegistrationId();
 
   public static SessionCipher createFor(Context context,

library/src/org/whispersystems/textsecure/crypto/SessionCipherV2.java

@@ -77,7 +77,9 @@ public class SessionCipherV2 extends SessionCipher {
   }
 
   @Override
-  public byte[] decrypt(byte[] decodedMessage) throws InvalidMessageException {
+  public byte[] decrypt(byte[] decodedMessage)
+      throws InvalidMessageException, DuplicateMessageException
+  {
     synchronized (SESSION_LOCK) {
       SessionRecordV2    sessionRecord  = getSessionRecord();
       SessionState       sessionState   = sessionRecord.getSessionState();
@@ -94,6 +96,7 @@ public class SessionCipherV2 extends SessionCipher {
 
       for (SessionState previousState : previousStates) {
         try {
+          Log.w("SessionCipherV2", "Attempting decrypt on previous state...");
           byte[] plaintext = decrypt(previousState, decodedMessage);
           sessionRecord.save();
 
@@ -108,7 +111,7 @@ public class SessionCipherV2 extends SessionCipher {
   }
 
   public byte[] decrypt(SessionState sessionState, byte[] decodedMessage)
-      throws InvalidMessageException
+      throws InvalidMessageException, DuplicateMessageException
   {
     if (!sessionState.hasSenderChain()) {
       throw new InvalidMessageException("Uninitialized session!");
@@ -167,18 +170,19 @@ public class SessionCipherV2 extends SessionCipher {
   private MessageKeys getOrCreateMessageKeys(SessionState sessionState,
                                              ECPublicKey theirEphemeral,
                                              ChainKey chainKey, int counter)
-      throws InvalidMessageException
+      throws InvalidMessageException, DuplicateMessageException
   {
     if (chainKey.getIndex() > counter) {
       if (sessionState.hasMessageKeys(theirEphemeral, counter)) {
         return sessionState.removeMessageKeys(theirEphemeral, counter);
       } else {
-        throw new InvalidMessageException("Received message with old counter!");
+        throw new DuplicateMessageException("Received message with old counter: " +
+                                                chainKey.getIndex() + " , " + counter);
       }
     }
 
-    if (chainKey.getIndex() - counter > 500) {
+    if (chainKey.getIndex() - counter > 2000) {
-      throw new InvalidMessageException("Over 500 messages into the future!");
+      throw new InvalidMessageException("Over 2000 messages into the future!");
     }
 
     while (chainKey.getIndex() < counter) {

res/values/strings.xml

@@ -298,6 +298,7 @@
     </string>
     <string name="SmsMessageRecord_received_updated_but_unknown_identity_information">Received updated but unknown identity information. Tap to validate identity.</string>
     <string name="SmsMessageRecord_secure_session_ended">Secure session ended.</string>
+    <string name="SmsMessageRecord_duplicate_message">Duplicate message.</string>
 
     <!-- ThreadRecord -->
     <string name="ThreadRecord_left_the_group">Left the group...</string>

src/org/thoughtcrime/securesms/crypto/DecryptingQueue.java

@@ -40,6 +40,7 @@ import org.thoughtcrime.securesms.service.PushReceiver;
 import org.thoughtcrime.securesms.service.SendReceiveService;
 import org.thoughtcrime.securesms.sms.SmsTransportDetails;
 import org.thoughtcrime.securesms.util.TextSecurePreferences;
+import org.whispersystems.textsecure.crypto.DuplicateMessageException;
 import org.whispersystems.textsecure.crypto.InvalidKeyException;
 import org.whispersystems.textsecure.crypto.InvalidMessageException;
 import org.whispersystems.textsecure.crypto.InvalidVersionException;
@@ -213,6 +214,9 @@ public class DecryptingQueue {
       } catch (RecipientFormattingException e) {
         Log.w("DecryptionQueue", e);
         sendResult(PushReceiver.RESULT_DECRYPT_FAILED);
+      } catch (DuplicateMessageException e) {
+        Log.w("DecryptingQueue", e);
+        sendResult(PushReceiver.RESULT_DECRYPT_DUPLICATE);
       }
     }
 
@@ -312,6 +316,9 @@ public class DecryptingQueue {
       } catch (InvalidMessageException ime) {
         Log.w("DecryptingQueue", ime);
         database.markAsDecryptFailed(messageId, threadId);
+      } catch (DuplicateMessageException dme) {
+        Log.w("DecryptingQueue", dme);
+        database.markAsDecryptDuplicate(messageId, threadId);
       } catch (MmsException mme) {
         Log.w("DecryptingQueue", mme);
         database.markAsDecryptFailed(messageId, threadId);
@@ -391,6 +398,10 @@ public class DecryptingQueue {
         Log.w("DecryptionQueue", e);
         database.markAsDecryptFailed(messageId);
         return;
+      } catch (DuplicateMessageException e) {
+        Log.w("DecryptionQueue", e);
+        database.markAsDecryptDuplicate(messageId);
+        return;
       }
 
       database.updateMessageBody(masterSecret, messageId, plaintextBody);

src/org/thoughtcrime/securesms/database/MmsDatabase.java

@@ -347,6 +347,11 @@ public class MmsDatabase extends Database implements MmsSmsColumns {
     notifyConversationListeners(threadId);
   }
 
+  public void markAsDecryptDuplicate(long messageId, long threadId) {
+    updateMailboxBitmask(messageId, Types.ENCRYPTION_MASK, Types.ENCRYPTION_REMOTE_DUPLICATE_BIT);
+    notifyConversationListeners(threadId);
+  }
+
   public void setMessagesRead(long threadId) {
     SQLiteDatabase database     = databaseHelper.getWritableDatabase();
     ContentValues contentValues = new ContentValues();

src/org/thoughtcrime/securesms/database/MmsSmsColumns.java

@@ -57,6 +57,7 @@ public interface MmsSmsColumns {
     protected static final long ENCRYPTION_REMOTE_BIT            = 0x20000000;
     protected static final long ENCRYPTION_REMOTE_FAILED_BIT     = 0x10000000;
     protected static final long ENCRYPTION_REMOTE_NO_SESSION_BIT = 0x08000000;
+    protected static final long ENCRYPTION_REMOTE_DUPLICATE_BIT  = 0x04000000;
 
     public static boolean isFailedMessageType(long type) {
       return (type & BASE_TYPE_MASK) == BASE_SENT_FAILED_TYPE;
@@ -145,6 +146,10 @@ public interface MmsSmsColumns {
       return (type & ENCRYPTION_REMOTE_FAILED_BIT) != 0;
     }
 
+    public static boolean isDuplicateMessageType(long type) {
+      return (type & ENCRYPTION_REMOTE_DUPLICATE_BIT) != 0;
+    }
+
     public static boolean isDecryptInProgressType(long type) {
       return
           (type & ENCRYPTION_REMOTE_BIT)     != 0 ||

src/org/thoughtcrime/securesms/database/SmsDatabase.java

@@ -186,6 +186,10 @@ public class SmsDatabase extends Database implements MmsSmsColumns {
     updateTypeBitmask(id, Types.ENCRYPTION_MASK, Types.ENCRYPTION_REMOTE_FAILED_BIT);
   }
 
+  public void markAsDecryptDuplicate(long id) {
+    updateTypeBitmask(id, Types.ENCRYPTION_MASK, Types.ENCRYPTION_REMOTE_DUPLICATE_BIT);
+  }
+
   public void markAsNoSession(long id) {
     updateTypeBitmask(id, Types.ENCRYPTION_MASK, Types.ENCRYPTION_REMOTE_NO_SESSION_BIT);
   }

src/org/thoughtcrime/securesms/database/model/MediaMmsMessageRecord.java

@@ -74,6 +74,8 @@ public class MediaMmsMessageRecord extends MessageRecord {
       return emphasisAdded(context.getString(R.string.MmsMessageRecord_decrypting_mms_please_wait));
     } else if (MmsDatabase.Types.isFailedDecryptType(type)) {
       return emphasisAdded(context.getString(R.string.MmsMessageRecord_bad_encrypted_mms_message));
+    } else if (MmsDatabase.Types.isDuplicateMessageType(type)) {
+      return emphasisAdded(context.getString(R.string.SmsMessageRecord_duplicate_message));
     } else if (MmsDatabase.Types.isNoRemoteSessionType(type)) {
       return emphasisAdded(context.getString(R.string.MmsMessageRecord_mms_message_encrypted_for_non_existing_session));
     } else if (!getBody().isPlaintext()) {

src/org/thoughtcrime/securesms/database/model/SmsMessageRecord.java

@@ -73,6 +73,8 @@ public class SmsMessageRecord extends MessageRecord {
       return emphasisAdded(context.getString(R.string.ConversationItem_received_key_exchange_message_click_to_process));
     } else if (SmsDatabase.Types.isFailedDecryptType(type)) {
       return emphasisAdded(context.getString(R.string.MessageDisplayHelper_bad_encrypted_message));
+    } else if (SmsDatabase.Types.isDuplicateMessageType(type)) {
+      return emphasisAdded(context.getString(R.string.SmsMessageRecord_duplicate_message));
     } else if (SmsDatabase.Types.isDecryptInProgressType(type)) {
       return emphasisAdded(context.getString(R.string.MessageDisplayHelper_decrypting_please_wait));
     } else if (SmsDatabase.Types.isNoRemoteSessionType(type)) {

src/org/thoughtcrime/securesms/service/PushReceiver.java

@@ -24,7 +24,6 @@ import org.thoughtcrime.securesms.sms.IncomingEndSessionMessage;
 import org.thoughtcrime.securesms.sms.IncomingKeyExchangeMessage;
 import org.thoughtcrime.securesms.sms.IncomingPreKeyBundleMessage;
 import org.thoughtcrime.securesms.sms.IncomingTextMessage;
-import org.thoughtcrime.securesms.sms.SmsTransportDetails;
 import org.thoughtcrime.securesms.util.TextSecurePreferences;
 import org.whispersystems.textsecure.crypto.InvalidKeyException;
 import org.whispersystems.textsecure.crypto.InvalidMessageException;
@@ -47,6 +46,7 @@ public class PushReceiver {
   public static final int RESULT_OK                = 0;
   public static final int RESULT_NO_SESSION        = 1;
   public static final int RESULT_DECRYPT_FAILED    = 2;
+  public static final int RESULT_DECRYPT_DUPLICATE = 3;
 
   private final Context       context;
   private final GroupReceiver groupReceiver;
@@ -72,6 +72,7 @@ public class PushReceiver {
     if      (result == RESULT_OK)                handleReceivedMessage(masterSecret, message, true);
     else if (result == RESULT_NO_SESSION)        handleReceivedMessageForNoSession(masterSecret, message);
     else if (result == RESULT_DECRYPT_FAILED)    handleReceivedCorruptedMessage(masterSecret, message, true);
+    else if (result == RESULT_DECRYPT_DUPLICATE) handleReceivedDuplicateMessage(message);
 
     DatabaseFactory.getPushDatabase(context).delete(messageId);
   }
@@ -255,6 +256,10 @@ public class PushReceiver {
     MessageNotifier.updateNotification(context, masterSecret, messageAndThreadId.second);
   }
 
+  private void handleReceivedDuplicateMessage(IncomingPushMessage message) {
+    Log.w("PushReceiver", "Received duplicate message: " + message.getSource() + " , " + message.getSourceDevice());
+  }
+
   private void handleReceivedCorruptedKey(MasterSecret masterSecret,
                                           IncomingPushMessage message,
                                           boolean invalidVersion)