5.7.2.0

* client: remove TLS handshake timeout

* remove comment

CHANGELOG.md

@@ -1,3 +1,35 @@
+# 5.7.2
+
+SMP agent:
+- fix connections failing when connecting via link due to race condition on slow network.
+- remove concurrency limit when waiting for connection subscription.
+- remove TLS timeout.
+
+# 5.7.1
+
+SMP agent:
+- increase timeout for TLS connection via SOCKS
+
+# 5.7.0
+
+Version 5.7.0.4
+
+_Please note_: the earliest SimpleX Chat clients supported by this version of the servers is 5.5.3 (released on February 11, 2024).
+
+SMP server:
+- increase max SMP protocol version to 7 (support for deniable authenticators).
+
+NTF server:
+- increase max NTF protocol version to 2 (support for deniable authenticators).
+
+XFTP server:
+- version handshake using ALPN.
+
+SMP agent:
+- increase timeouts for XFTP files.
+- don't send commands after timeout.
+- PQ encryption support.
+
 # 5.6.2
 
 Version 5.6.2.2.

package.yaml

@@ -1,5 +1,5 @@
 name: simplexmq
-version: 5.7.0.2
+version: 5.7.2.0
 synopsis: SimpleXMQ message broker
 description: |
   This package includes <./docs/Simplex-Messaging-Server.html server>,

simplexmq.cabal

@@ -5,7 +5,7 @@ cabal-version: 1.12
 -- see: https://github.com/sol/hpack
 
 name:           simplexmq
-version:        5.7.0.2
+version:        5.7.2.0
 synopsis:       SimpleXMQ message broker
 description:    This package includes <./docs/Simplex-Messaging-Server.html server>,
                 <./docs/Simplex-Messaging-Client.html client> and

src/Simplex/Messaging/Agent.hs

@@ -55,6 +55,7 @@ module Simplex.Messaging.Agent
     deleteConnectionAsync,
     deleteConnectionsAsync,
     createConnection,
+    prepareConnectionToJoin,
     joinConnection,
     allowConnection,
     acceptContact,
@@ -149,7 +150,7 @@ import Simplex.FileTransfer.Protocol (FileParty (..))
 import Simplex.FileTransfer.Util (removePath)
 import Simplex.Messaging.Agent.Client
 import Simplex.Messaging.Agent.Env.SQLite
-import Simplex.Messaging.Agent.Lock (withLock', withLock)
+import Simplex.Messaging.Agent.Lock (withLock, withLock')
 import Simplex.Messaging.Agent.NtfSubSupervisor
 import Simplex.Messaging.Agent.Protocol
 import Simplex.Messaging.Agent.RetryInterval
@@ -160,7 +161,7 @@ import qualified Simplex.Messaging.Agent.Store.SQLite.Migrations as Migrations
 import Simplex.Messaging.Client (ProtocolClient (..), ServerTransmission)
 import qualified Simplex.Messaging.Crypto as C
 import Simplex.Messaging.Crypto.File (CryptoFile, CryptoFileArgs)
-import Simplex.Messaging.Crypto.Ratchet (PQEncryption, PQSupport (..), pattern PQEncOn, pattern PQEncOff, pattern PQSupportOn, pattern PQSupportOff)
+import Simplex.Messaging.Crypto.Ratchet (PQEncryption, PQSupport (..), pattern PQEncOff, pattern PQEncOn, pattern PQSupportOff, pattern PQSupportOn)
 import qualified Simplex.Messaging.Crypto.Ratchet as CR
 import Simplex.Messaging.Encoding
 import Simplex.Messaging.Encoding.String
@@ -198,7 +199,7 @@ getSMPAgentClient_ clientId cfg initServers store backgroundMode =
   liftIO $ newSMPAgentEnv cfg store >>= runReaderT runAgent
   where
     runAgent = do
-      c@AgentClient {acThread}  <- atomically . newAgentClient clientId initServers =<< ask
+      c@AgentClient {acThread} <- atomically . newAgentClient clientId initServers =<< ask
       t <- runAgentThreads c `forkFinally` const (liftIO $ disconnectAgentClient c)
       atomically . writeTVar acThread . Just =<< mkWeakThreadId t
       pure c
@@ -239,7 +240,7 @@ createUser c = withAgentEnv c .: createUser' c
 {-# INLINE createUser #-}
 
 -- | Delete user record optionally deleting all user's connections on SMP servers
-deleteUser :: AgentClient -> UserId -> Bool -> AE  ()
+deleteUser :: AgentClient -> UserId -> Bool -> AE ()
 deleteUser c = withAgentEnv c .: deleteUser' c
 {-# INLINE deleteUser #-}
 
@@ -288,9 +289,18 @@ createConnection :: AgentClient -> UserId -> Bool -> SConnectionMode c -> Maybe
 createConnection c userId enableNtfs = withAgentEnv c .:: newConn c userId "" enableNtfs
 {-# INLINE createConnection #-}
 
--- | Join SMP agent connection (JOIN command)
-joinConnection :: AgentClient -> UserId -> Bool -> ConnectionRequestUri c -> ConnInfo -> PQSupport -> SubscriptionMode -> AE ConnId
-joinConnection c userId enableNtfs = withAgentEnv c .:: joinConn c userId "" enableNtfs
+-- | Create SMP agent connection without queue (to be joined with joinConnection passing connection ID).
+-- This method is required to prevent race condition when confirmation from peer is received before
+-- the caller of joinConnection saves connection ID to the database.
+-- Instead of it we could send confirmation asynchronously, but then it would be harder to report
+-- "link deleted" (SMP AUTH) interactively, so this approach is simpler overall.
+prepareConnectionToJoin :: AgentClient -> UserId -> Bool -> ConnectionRequestUri c -> PQSupport -> AE ConnId
+prepareConnectionToJoin c userId enableNtfs = withAgentEnv c .: newConnToJoin c userId "" enableNtfs
+
+-- | Join SMP agent connection (JOIN command).
+joinConnection :: AgentClient -> UserId -> Maybe ConnId -> Bool -> ConnectionRequestUri c -> ConnInfo -> PQSupport -> SubscriptionMode -> AE ConnId
+joinConnection c userId Nothing enableNtfs = withAgentEnv c .:: joinConn c userId "" False enableNtfs
+joinConnection c userId (Just connId) enableNtfs = withAgentEnv c .:: joinConn c userId connId True enableNtfs
 {-# INLINE joinConnection #-}
 
 -- | Allow connection to continue after CONF notification (LET command)
@@ -575,7 +585,7 @@ processCommand :: AgentClient -> (EntityId, APartyCmd 'Client) -> AM (EntityId,
 processCommand c (connId, APC e cmd) =
   second (APC e) <$> case cmd of
     NEW enableNtfs (ACM cMode) pqIK subMode -> second (INV . ACR cMode) <$> newConn c userId connId enableNtfs cMode Nothing pqIK subMode
-    JOIN enableNtfs (ACR _ cReq) pqEnc subMode connInfo -> (,OK) <$> joinConn c userId connId enableNtfs cReq connInfo pqEnc subMode
+    JOIN enableNtfs (ACR _ cReq) pqEnc subMode connInfo -> (,OK) <$> joinConn c userId connId False enableNtfs cReq connInfo pqEnc subMode
     LET confId ownCInfo -> allowConnection' c connId confId ownCInfo $> (connId, OK)
     ACPT invId pqEnc ownCInfo -> (,OK) <$> acceptContact' c connId True invId ownCInfo pqEnc SMSubscribe
     RJCT invId -> rejectContact' c connId invId $> (connId, OK)
@@ -708,11 +718,14 @@ switchConnectionAsync' c corrId connId =
 
 newConn :: AgentClient -> UserId -> ConnId -> Bool -> SConnectionMode c -> Maybe CRClientData -> CR.InitialKeys -> SubscriptionMode -> AM (ConnId, ConnectionRequestUri c)
 newConn c userId connId enableNtfs cMode clientData pqInitKeys subMode =
-  getSMPServer c userId >>= newConnSrv c userId connId enableNtfs cMode clientData pqInitKeys subMode
+  getSMPServer c userId >>= newConnSrv c userId connId False enableNtfs cMode clientData pqInitKeys subMode
 
-newConnSrv :: AgentClient -> UserId -> ConnId -> Bool -> SConnectionMode c -> Maybe CRClientData -> CR.InitialKeys -> SubscriptionMode -> SMPServerWithAuth -> AM (ConnId, ConnectionRequestUri c)
-newConnSrv c userId connId enableNtfs cMode clientData pqInitKeys subMode srv = do
-  connId' <- newConnNoQueues c userId connId enableNtfs cMode (CR.connPQEncryption pqInitKeys)
+newConnSrv :: AgentClient -> UserId -> ConnId -> Bool -> Bool -> SConnectionMode c -> Maybe CRClientData -> CR.InitialKeys -> SubscriptionMode -> SMPServerWithAuth -> AM (ConnId, ConnectionRequestUri c)
+newConnSrv c userId connId hasNewConn enableNtfs cMode clientData pqInitKeys subMode srv = do
+  connId' <-
+    if hasNewConn
+      then pure connId
+      else newConnNoQueues c userId connId enableNtfs cMode (CR.connPQEncryption pqInitKeys)
   newRcvConnSrv c userId connId' enableNtfs cMode clientData pqInitKeys subMode srv
 
 newRcvConnSrv :: AgentClient -> UserId -> ConnId -> Bool -> SConnectionMode c -> Maybe CRClientData -> CR.InitialKeys -> SubscriptionMode -> SMPServerWithAuth -> AM (ConnId, ConnectionRequestUri c)
@@ -738,18 +751,36 @@ newRcvConnSrv c userId connId enableNtfs cMode clientData pqInitKeys subMode srv
       withStore' c $ \db -> createRatchetX3dhKeys db connId pk1 pk2 pKem
       pure (connId, CRInvitationUri crData $ toVersionRangeT e2eRcvParams e2eEncryptVRange)
 
-joinConn :: AgentClient -> UserId -> ConnId -> Bool -> ConnectionRequestUri c -> ConnInfo -> PQSupport -> SubscriptionMode -> AM ConnId
-joinConn c userId connId enableNtfs cReq cInfo pqSupport subMode = do
+newConnToJoin :: forall c. AgentClient -> UserId -> ConnId -> Bool -> ConnectionRequestUri c -> PQSupport -> AM ConnId
+newConnToJoin c userId connId enableNtfs cReq pqSup = case cReq of
+  CRInvitationUri {} ->
+    lift (compatibleInvitationUri cReq) >>= \case
+      Just (_, (Compatible (CR.E2ERatchetParams v _ _ _)), aVersion) -> create aVersion (Just v)
+      Nothing -> throwError $ AGENT A_VERSION
+  CRContactUri {} ->
+    lift (compatibleContactUri cReq) >>= \case
+      Just (_, aVersion) -> create aVersion Nothing
+      Nothing -> throwError $ AGENT A_VERSION
+  where
+    create :: Compatible VersionSMPA -> Maybe CR.VersionE2E -> AM ConnId
+    create (Compatible connAgentVersion) e2eV_ = do
+      g <- asks random
+      let pqSupport = pqSup `CR.pqSupportAnd` versionPQSupport_ connAgentVersion e2eV_
+          cData = ConnData {userId, connId, connAgentVersion, enableNtfs, lastExternalSndId = 0, deleted = False, ratchetSyncState = RSOk, pqSupport}
+      withStore c $ \db -> createNewConn db g cData SCMInvitation
+
+joinConn :: AgentClient -> UserId -> ConnId -> Bool -> Bool -> ConnectionRequestUri c -> ConnInfo -> PQSupport -> SubscriptionMode -> AM ConnId
+joinConn c userId connId hasNewConn enableNtfs cReq cInfo pqSupport subMode = do
   srv <- case cReq of
     CRInvitationUri ConnReqUriData {crSmpQueues = q :| _} _ ->
       getNextServer c userId [qServer q]
     _ -> getSMPServer c userId
-  joinConnSrv c userId connId enableNtfs cReq cInfo pqSupport subMode srv
+  joinConnSrv c userId connId hasNewConn enableNtfs cReq cInfo pqSupport subMode srv
 
-startJoinInvitation :: UserId -> ConnId -> Bool -> ConnectionRequestUri 'CMInvitation -> PQSupport -> AM (Compatible VersionSMPA, ConnData, NewSndQueue, CR.Ratchet 'C.X448, CR.SndE2ERatchetParams 'C.X448)
+startJoinInvitation :: UserId -> ConnId -> Bool -> ConnectionRequestUri 'CMInvitation -> PQSupport -> AM (ConnData, NewSndQueue, CR.Ratchet 'C.X448, CR.SndE2ERatchetParams 'C.X448)
 startJoinInvitation userId connId enableNtfs cReqUri pqSup =
   lift (compatibleInvitationUri cReqUri) >>= \case
-    Just (qInfo, (Compatible e2eRcvParams@(CR.E2ERatchetParams v _ rcDHRr kem_)), aVersion@(Compatible connAgentVersion)) -> do
+    Just (qInfo, (Compatible e2eRcvParams@(CR.E2ERatchetParams v _ rcDHRr kem_)), Compatible connAgentVersion) -> do
       g <- asks random
       let pqSupport = pqSup `CR.pqSupportAnd` versionPQSupport_ connAgentVersion (Just v)
       (pk1, pk2, pKem, e2eSndParams) <- liftIO $ CR.generateSndE2EParams g v (CR.replyKEM_ v kem_ pqSupport)
@@ -760,7 +791,7 @@ startJoinInvitation userId connId enableNtfs cReqUri pqSup =
           rc = CR.initSndRatchet rcVs rcDHRr rcDHRs rcParams
       q <- lift $ newSndQueue userId "" qInfo
       let cData = ConnData {userId, connId, connAgentVersion, enableNtfs, lastExternalSndId = 0, deleted = False, ratchetSyncState = RSOk, pqSupport}
-      pure (aVersion, cData, q, rc, e2eSndParams)
+      pure (cData, q, rc, e2eSndParams)
     Nothing -> throwError $ AGENT A_VERSION
 
 connRequestPQSupport :: AgentClient -> PQSupport -> ConnectionRequestUri c -> IO (Maybe (VersionSMPA, PQSupport))
@@ -786,40 +817,43 @@ compatibleContactUri (CRContactUri ConnReqUriData {crAgentVRange, crSmpQueues =
   AgentConfig {smpClientVRange, smpAgentVRange} <- asks config
   pure $
     (,)
-      <$> (qUri `compatibleVersion` smpClientVRange) 
+      <$> (qUri `compatibleVersion` smpClientVRange)
       <*> (crAgentVRange `compatibleVersion` smpAgentVRange)
 
 versionPQSupport_ :: VersionSMPA -> Maybe CR.VersionE2E -> PQSupport
 versionPQSupport_ agentV e2eV_ = PQSupport $ agentV >= pqdrSMPAgentVersion && maybe True (>= CR.pqRatchetE2EEncryptVersion) e2eV_
 {-# INLINE versionPQSupport_ #-}
 
-joinConnSrv :: AgentClient -> UserId -> ConnId -> Bool -> ConnectionRequestUri c -> ConnInfo -> PQSupport -> SubscriptionMode -> SMPServerWithAuth -> AM ConnId
-joinConnSrv c userId connId enableNtfs inv@CRInvitationUri {} cInfo pqSup subMode srv =
+joinConnSrv :: AgentClient -> UserId -> ConnId -> Bool -> Bool -> ConnectionRequestUri c -> ConnInfo -> PQSupport -> SubscriptionMode -> SMPServerWithAuth -> AM ConnId
+joinConnSrv c userId connId hasNewConn enableNtfs inv@CRInvitationUri {} cInfo pqSup subMode srv =
   withInvLock c (strEncode inv) "joinConnSrv" $ do
-    (aVersion, cData, q, rc, e2eSndParams) <- startJoinInvitation userId connId enableNtfs inv pqSup
+    (cData, q, rc, e2eSndParams) <- startJoinInvitation userId connId enableNtfs inv pqSup
     g <- asks random
     (connId', sq) <- withStore c $ \db -> runExceptT $ do
-      r@(connId', _) <- ExceptT $ createSndConn db g cData q
+      r@(connId', _) <-
+        if hasNewConn
+          then (connId,) <$> ExceptT (updateNewConnSnd db connId q)
+          else ExceptT $ createSndConn db g cData q
       liftIO $ createRatchet db connId' rc
       pure r
     let cData' = (cData :: ConnData) {connId = connId'}
-    tryError (confirmQueue aVersion c cData' sq srv cInfo (Just e2eSndParams) subMode) >>= \case
+    tryError (confirmQueue c cData' sq srv cInfo (Just e2eSndParams) subMode) >>= \case
       Right _ -> pure connId'
       Left e -> do
         -- possible improvement: recovery for failure on network timeout, see rfcs/2022-04-20-smp-conf-timeout-recovery.md
         void $ withStore' c $ \db -> deleteConn db Nothing connId'
         throwError e
-joinConnSrv c userId connId enableNtfs cReqUri@CRContactUri {} cInfo pqSup subMode srv =
+joinConnSrv c userId connId hasNewConn enableNtfs cReqUri@CRContactUri {} cInfo pqSup subMode srv =
   lift (compatibleContactUri cReqUri) >>= \case
     Just (qInfo, vrsn) -> do
-      (connId', cReq) <- newConnSrv c userId connId enableNtfs SCMInvitation Nothing (CR.IKNoPQ pqSup) subMode srv
+      (connId', cReq) <- newConnSrv c userId connId hasNewConn enableNtfs SCMInvitation Nothing (CR.IKNoPQ pqSup) subMode srv
       sendInvitation c userId qInfo vrsn cReq cInfo
       pure connId'
     Nothing -> throwError $ AGENT A_VERSION
 
 joinConnSrvAsync :: AgentClient -> UserId -> ConnId -> Bool -> ConnectionRequestUri c -> ConnInfo -> PQSupport -> SubscriptionMode -> SMPServerWithAuth -> AM ()
 joinConnSrvAsync c userId connId enableNtfs inv@CRInvitationUri {} cInfo pqSupport subMode srv = do
-  (_aVersion, cData, q, rc, e2eSndParams) <- startJoinInvitation userId connId enableNtfs inv pqSupport
+  (cData, q, rc, e2eSndParams) <- startJoinInvitation userId connId enableNtfs inv pqSupport
   q' <- withStore c $ \db -> runExceptT $ do
     liftIO $ createRatchet db connId rc
     ExceptT $ updateNewConnSnd db connId q
@@ -861,7 +895,7 @@ acceptContact' c connId enableNtfs invId ownConnInfo pqSupport subMode = withCon
   withStore c (`getConn` contactConnId) >>= \case
     SomeConn _ (ContactConnection ConnData {userId} _) -> do
       withStore' c $ \db -> acceptInvitation db invId ownConnInfo
-      joinConn c userId connId enableNtfs connReq ownConnInfo pqSupport subMode `catchAgentError` \err -> do
+      joinConn c userId connId False enableNtfs connReq ownConnInfo pqSupport subMode `catchAgentError` \err -> do
         withStore' c (`unacceptInvitation` invId)
         throwError err
     _ -> throwError $ CMD PROHIBITED
@@ -1207,7 +1241,7 @@ enqueueMessage c cData sq msgFlags aMessage =
 {-# INLINE enqueueMessage #-}
 
 -- this function is used only for sending messages in batch, it returns the list of successes to enqueue additional deliveries
-enqueueMessageB :: forall t. (Traversable t) => AgentClient -> t (Either AgentErrorType (ConnData, NonEmpty SndQueue, Maybe PQEncryption, MsgFlags, AMessage)) -> AM' (t (Either AgentErrorType ((AgentMsgId, PQEncryption), Maybe (ConnData, [SndQueue], AgentMsgId))))
+enqueueMessageB :: forall t. Traversable t => AgentClient -> t (Either AgentErrorType (ConnData, NonEmpty SndQueue, Maybe PQEncryption, MsgFlags, AMessage)) -> AM' (t (Either AgentErrorType ((AgentMsgId, PQEncryption), Maybe (ConnData, [SndQueue], AgentMsgId))))
 enqueueMessageB c reqs = do
   cfg <- asks config
   reqMids <- withStoreBatch c $ \db -> fmap (bindRight $ storeSentMsg db cfg) reqs
@@ -1239,7 +1273,7 @@ enqueueSavedMessage :: AgentClient -> ConnData -> AgentMsgId -> SndQueue -> AM'
 enqueueSavedMessage c cData msgId sq = enqueueSavedMessageB c $ Identity (cData, [sq], msgId)
 {-# INLINE enqueueSavedMessage #-}
 
-enqueueSavedMessageB :: (Foldable t) => AgentClient -> t (ConnData, [SndQueue], AgentMsgId) -> AM' ()
+enqueueSavedMessageB :: Foldable t => AgentClient -> t (ConnData, [SndQueue], AgentMsgId) -> AM' ()
 enqueueSavedMessageB c reqs = do
   -- saving to the database is in the start to avoid race conditions when delivery is read from queue before it is saved
   void $ withStoreBatch' c $ \db -> concatMap (storeDeliveries db) reqs
@@ -2565,8 +2599,8 @@ confirmQueueAsync c cData sq srv connInfo e2eEncryption_ subMode = do
   storeConfirmation c cData sq e2eEncryption_ =<< mkAgentConfirmation c cData sq srv connInfo subMode
   lift $ submitPendingMsg c cData sq
 
-confirmQueue :: Compatible VersionSMPA -> AgentClient -> ConnData -> SndQueue -> SMPServerWithAuth -> ConnInfo -> Maybe (CR.SndE2ERatchetParams 'C.X448) -> SubscriptionMode -> AM ()
-confirmQueue (Compatible agentVersion) c cData@ConnData {connId, pqSupport} sq srv connInfo e2eEncryption_ subMode = do
+confirmQueue :: AgentClient -> ConnData -> SndQueue -> SMPServerWithAuth -> ConnInfo -> Maybe (CR.SndE2ERatchetParams 'C.X448) -> SubscriptionMode -> AM ()
+confirmQueue c cData@ConnData {connId, connAgentVersion, pqSupport} sq srv connInfo e2eEncryption_ subMode = do
   msg <- mkConfirmation =<< mkAgentConfirmation c cData sq srv connInfo subMode
   sendConfirmation c sq msg
   withStore' c $ \db -> setSndQueueStatus db sq Confirmed
@@ -2578,7 +2612,7 @@ confirmQueue (Compatible agentVersion) c cData@ConnData {connId, pqSupport} sq s
         void . liftIO $ updateSndIds db connId
         let pqEnc = CR.pqSupportToEnc pqSupport
         (encConnInfo, _) <- agentRatchetEncrypt db cData (smpEncode aMessage) e2eEncConnInfoLength (Just pqEnc) currentE2EVersion
-        pure . smpEncode $ AgentConfirmation {agentVersion, e2eEncryption_, encConnInfo}
+        pure . smpEncode $ AgentConfirmation {agentVersion = connAgentVersion, e2eEncryption_, encConnInfo}
 
 mkAgentConfirmation :: AgentClient -> ConnData -> SndQueue -> SMPServerWithAuth -> ConnInfo -> SubscriptionMode -> AM AgentMessage
 mkAgentConfirmation c cData sq srv connInfo subMode = do

src/Simplex/Messaging/Client.hs

@@ -97,7 +97,7 @@ import Data.List (find)
 import Data.List.NonEmpty (NonEmpty (..))
 import qualified Data.List.NonEmpty as L
 import Data.Maybe (fromMaybe)
-import Data.Time.Clock (UTCTime (..), getCurrentTime)
+import Data.Time.Clock (UTCTime (..), diffUTCTime, getCurrentTime)
 import Network.Socket (ServiceName)
 import Numeric.Natural
 import qualified Simplex.Messaging.Crypto as C
@@ -110,10 +110,9 @@ import Simplex.Messaging.Transport
 import Simplex.Messaging.Transport.Client (SocksProxy, TransportClientConfig (..), TransportHost (..), defaultTcpConnectTimeout, runTransportClient)
 import Simplex.Messaging.Transport.KeepAlive
 import Simplex.Messaging.Transport.WebSockets (WS)
-import Simplex.Messaging.Util (bshow, raceAny_, threadDelay', whenM)
+import Simplex.Messaging.Util (bshow, diffToMicroseconds, raceAny_, threadDelay', whenM)
 import Simplex.Messaging.Version
 import System.Timeout (timeout)
-import UnliftIO (pooledMapConcurrentlyN)
 
 -- | 'SMPClient' is a handle used to send commands to a specific SMP server.
 --
@@ -131,7 +130,9 @@ data PClient v err msg = PClient
     transportHost :: TransportHost,
     tcpTimeout :: Int,
     rcvConcurrency :: Int,
-    pingErrorCount :: TVar Int,
+    sendPings :: TVar Bool,
+    lastReceived :: TVar UTCTime,
+    timeoutErrorCount :: TVar Int,
     clientCorrId :: TVar ChaChaDRG,
     sentCommands :: TMap CorrId (Request err msg),
     sndQ :: TBQueue (TVar Bool, ByteString),
@@ -141,10 +142,13 @@ data PClient v err msg = PClient
 
 smpClientStub :: TVar ChaChaDRG -> ByteString -> VersionSMP -> Maybe (THandleAuth 'TClient) -> STM SMPClient
 smpClientStub g sessionId thVersion thAuth = do
+  let ts = UTCTime (read "2024-03-31") 0
   connected <- newTVar False
   clientCorrId <- C.newRandomDRG g
   sentCommands <- TM.empty
-  pingErrorCount <- newTVar 0
+  sendPings <- newTVar False
+  lastReceived <- newTVar ts
+  timeoutErrorCount <- newTVar 0
   sndQ <- newTBQueue 100
   rcvQ <- newTBQueue 100
   return
@@ -159,7 +163,7 @@ smpClientStub g sessionId thVersion thAuth = do
               implySessId = thVersion >= authCmdsSMPVersion,
               batch = True
             },
-        sessionTs = UTCTime (read "2024-03-31") 0,
+        sessionTs = ts,
         client_ =
           PClient
             { connected,
@@ -167,7 +171,9 @@ smpClientStub g sessionId thVersion thAuth = do
               transportHost = "localhost",
               tcpTimeout = 15_000_000,
               rcvConcurrency = 8,
-              pingErrorCount,
+              sendPings,
+              lastReceived,
+              timeoutErrorCount,
               clientCorrId,
               sentCommands,
               sndQ,
@@ -215,7 +221,7 @@ data NetworkConfig = NetworkConfig
     tcpKeepAlive :: Maybe KeepAliveOpts,
     -- | period for SMP ping commands (microseconds, 0 to disable)
     smpPingInterval :: Int64,
-    -- | the count of PING errors after which SMP client terminates (and will be reconnected), 0 to disable
+    -- | the count of timeout errors after which SMP client terminates (and will be reconnected), 0 to disable
     smpPingCount :: Int,
     logTLSErrors :: Bool
   }
@@ -329,15 +335,17 @@ getProtocolClient :: forall v err msg. Protocol v err msg => TVar ChaChaDRG -> T
 getProtocolClient g transportSession@(_, srv, _) cfg@ProtocolClientConfig {qSize, networkConfig, serverVRange, agreeSecret} msgQ disconnected = do
   case chooseTransportHost networkConfig (host srv) of
     Right useHost ->
-      (atomically (mkProtocolClient useHost) >>= runClient useTransport useHost)
+      (getCurrentTime >>= atomically . mkProtocolClient useHost >>= runClient useTransport useHost)
         `catch` \(e :: IOException) -> pure . Left $ PCEIOError e
     Left e -> pure $ Left e
   where
     NetworkConfig {tcpConnectTimeout, tcpTimeout, rcvConcurrency, smpPingInterval} = networkConfig
-    mkProtocolClient :: TransportHost -> STM (PClient v err msg)
-    mkProtocolClient transportHost = do
+    mkProtocolClient :: TransportHost -> UTCTime -> STM (PClient v err msg)
+    mkProtocolClient transportHost ts = do
       connected <- newTVar False
-      pingErrorCount <- newTVar 0
+      sendPings <- newTVar False
+      lastReceived <- newTVar ts
+      timeoutErrorCount <- newTVar 0
       clientCorrId <- C.newRandomDRG g
       sentCommands <- TM.empty
       sndQ <- newTBQueue qSize
@@ -348,7 +356,9 @@ getProtocolClient g transportSession@(_, srv, _) cfg@ProtocolClientConfig {qSize
             transportSession,
             transportHost,
             tcpTimeout,
-            pingErrorCount,
+            sendPings,
+            lastReceived,
+            timeoutErrorCount,
             clientCorrId,
             sentCommands,
             rcvConcurrency,
@@ -386,6 +396,7 @@ getProtocolClient g transportSession@(_, srv, _) cfg@ProtocolClientConfig {qSize
         Right th@THandle {params} -> do
           sessionTs <- getCurrentTime
           let c' = ProtocolClient {action = Nothing, client_ = c, thParams = params, sessionTs}
+          atomically $ writeTVar (lastReceived c) sessionTs
           atomically $ do
             writeTVar (connected c) True
             putTMVar cVar $ Right c'
@@ -396,17 +407,29 @@ getProtocolClient g transportSession@(_, srv, _) cfg@ProtocolClientConfig {qSize
     send ProtocolClient {client_ = PClient {sndQ}} h = forever $ atomically (readTBQueue sndQ) >>= \(active, s) -> whenM (readTVarIO active) (void $ tPutLog h s)
 
     receive :: Transport c => ProtocolClient v err msg -> THandle v c 'TClient -> IO ()
-    receive ProtocolClient {client_ = PClient {rcvQ}} h = forever $ tGet h >>= atomically . writeTBQueue rcvQ
+    receive ProtocolClient {client_ = PClient {rcvQ, lastReceived, timeoutErrorCount}} h = forever $ do
+      tGet h >>= atomically . writeTBQueue rcvQ
+      getCurrentTime >>= atomically . writeTVar lastReceived
+      atomically $ writeTVar timeoutErrorCount 0
 
     ping :: ProtocolClient v err msg -> IO ()
-    ping c@ProtocolClient {client_ = PClient {pingErrorCount}} = do
-      threadDelay' smpPingInterval
-      runExceptT (sendProtocolCommand c Nothing "" $ protocolPing @v @err @msg) >>= \case
-        Left PCEResponseTimeout -> do
-          cnt <- atomically $ stateTVar pingErrorCount $ \cnt -> (cnt + 1, cnt + 1)
-          when (maxCnt == 0 || cnt < maxCnt) $ ping c
-        _ -> ping c -- sendProtocolCommand resets pingErrorCount
+    ping c@ProtocolClient {client_ = PClient {sendPings, lastReceived, timeoutErrorCount}} = loop smpPingInterval
       where
+        loop :: Int64 -> IO ()
+        loop delay = do
+          threadDelay' delay
+          diff <- diffUTCTime <$> getCurrentTime <*> readTVarIO lastReceived
+          let idle = diffToMicroseconds diff
+              remaining = smpPingInterval - idle
+          if remaining > 1_000_000 -- delay pings only for significant time
+            then loop remaining
+            else do
+              whenM (readTVarIO sendPings) $ void . runExceptT $ sendProtocolCommand c Nothing "" (protocolPing @v @err @msg)
+              -- sendProtocolCommand/getResponse updates counter for each command
+              cnt <- readTVarIO timeoutErrorCount
+              -- drop client when maxCnt of commands have timed out in sequence, but only after some time has passed after last received response
+              when (maxCnt == 0 || cnt < maxCnt || diff < recoverWindow) $ loop smpPingInterval
+        recoverWindow = 15 * 60 -- seconds
         maxCnt = smpPingCount networkConfig
 
     process :: ProtocolClient v err msg -> IO ()
@@ -504,15 +527,18 @@ createSMPQueue c (rKey, rpKey) dhKey auth subMode =
 --
 -- https://github.com/simplex-chat/simplexmq/blob/master/protocol/simplex-messaging.md#subscribe-to-queue
 subscribeSMPQueue :: SMPClient -> RcvPrivateAuthKey -> RecipientId -> ExceptT SMPClientError IO ()
-subscribeSMPQueue c rpKey rId =
+subscribeSMPQueue c@ProtocolClient {client_ = PClient {sendPings}} rpKey rId = do
+  liftIO . atomically $ writeTVar sendPings True
   sendSMPCommand c (Just rpKey) rId SUB >>= \case
-    OK -> return ()
+    OK -> pure ()
     cmd@MSG {} -> liftIO $ writeSMPMessage c rId cmd
     r -> throwE . PCEUnexpectedResponse $ bshow r
 
 -- | Subscribe to multiple SMP queues batching commands if supported.
 subscribeSMPQueues :: SMPClient -> NonEmpty (RcvPrivateAuthKey, RecipientId) -> IO (NonEmpty (Either SMPClientError ()))
-subscribeSMPQueues c qs = sendProtocolCommands c cs >>= mapM (processSUBResponse c)
+subscribeSMPQueues c@ProtocolClient {client_ = PClient {sendPings}} qs = do
+  atomically $ writeTVar sendPings True
+  sendProtocolCommands c cs >>= mapM (processSUBResponse c)
   where
     cs = L.map (\(rpKey, rId) -> (Just rpKey, rId, Cmd SRecipient SUB)) qs
 
@@ -691,7 +717,7 @@ sendBatch c@ProtocolClient {client_ = PClient {rcvConcurrency, sndQ}} b = do
       | n > 0 -> do
           active <- newTVarIO True
           atomically $ writeTBQueue sndQ (active, s)
-          pooledMapConcurrentlyN rcvConcurrency (getResponse c active) rs
+          mapConcurrently (getResponse c active) rs
       | otherwise -> pure []
     TBTransmission s r -> do
       active <- newTVarIO True
@@ -700,7 +726,7 @@ sendBatch c@ProtocolClient {client_ = PClient {rcvConcurrency, sndQ}} b = do
 
 -- | Send Protocol command
 sendProtocolCommand :: forall v err msg. ProtocolEncoding v err (ProtoCommand msg) => ProtocolClient v err msg -> Maybe C.APrivateAuthKey -> EntityId -> ProtoCommand msg -> ExceptT (ProtocolClientError err) IO msg
-sendProtocolCommand c@ProtocolClient {client_ = PClient {tcpTimeout, sndQ}, thParams = THandleParams {batch, blockSize}} pKey entId cmd =
+sendProtocolCommand c@ProtocolClient {client_ = PClient {sndQ}, thParams = THandleParams {batch, blockSize}} pKey entId cmd =
   ExceptT $ uncurry sendRecv =<< mkTransmission c (pKey, entId, cmd)
   where
     -- two separate "atomically" needed to avoid blocking
@@ -711,23 +737,23 @@ sendProtocolCommand c@ProtocolClient {client_ = PClient {tcpTimeout, sndQ}, thPa
         | B.length s > blockSize - 2 -> pure . Left $ PCETransportError TELargeMsg
         | otherwise -> do
             active <- newTVarIO True
-            timeout tcpSendTimeout (atomically $ writeTBQueue sndQ (active, s)) >>= \case
-              Nothing -> pure $ Left PCEResponseTimeout
-              Just () -> response <$> getResponse c active r
+            atomically (writeTBQueue sndQ (active, s))
+            response <$> getResponse c active r
         where
-          -- TODO: move to configuration
-          tcpSendTimeout = tcpTimeout * 3 -- conservative timeout, allowing some asymmetry in uplink
           s
             | batch = tEncodeBatch1 t
             | otherwise = tEncode t
 
 -- TODO switch to timeout or TimeManager that supports Int64
 getResponse :: ProtocolClient v err msg -> TVar Bool -> Request err msg -> IO (Response err msg)
-getResponse ProtocolClient {client_ = PClient {tcpTimeout, pingErrorCount, sentCommands}} active Request {corrId, entityId, responseVar} = do
+getResponse ProtocolClient {client_ = PClient {tcpTimeout, timeoutErrorCount, sentCommands}} active Request {corrId, entityId, responseVar} = do
   response <-
     timeout tcpTimeout (atomically (takeTMVar responseVar)) >>= \case
-      Just r -> atomically (writeTVar pingErrorCount 0) $> r
-      Nothing -> atomically (writeTVar active False >> TM.delete corrId sentCommands) $> Left PCEResponseTimeout
+      Just r -> atomically (writeTVar timeoutErrorCount 0) $> r
+      Nothing -> do
+        atomically (writeTVar active False >> TM.delete corrId sentCommands)
+        atomically $ modifyTVar' timeoutErrorCount (+ 1)
+        pure $ Left PCEResponseTimeout
   pure Response {entityId, response}
 
 mkTransmission :: forall v err msg. ProtocolEncoding v err (ProtoCommand msg) => ProtocolClient v err msg -> ClientCommand msg -> IO (PCTransmission err msg)

src/Simplex/Messaging/Compression.hs

@@ -4,20 +4,9 @@
 module Simplex.Messaging.Compression where
 
 import qualified Codec.Compression.Zstd as Z1
-import qualified Codec.Compression.Zstd.FFI as Z
-import Control.Monad (forM)
-import Control.Monad.Except
-import Control.Monad.IO.Class
 import Data.ByteString (ByteString)
 import qualified Data.ByteString as B
-import qualified Data.ByteString.Unsafe as B
-import Data.Either (fromRight)
-import Data.List.NonEmpty (NonEmpty)
-import Foreign
-import Foreign.C.Types
-import GHC.IO (unsafePerformIO)
 import Simplex.Messaging.Encoding
-import UnliftIO.Exception (bracket)
 
 data Compressed
   = -- | Short messages are left intact to skip copying and FFI festivities.
@@ -42,49 +31,15 @@ instance Encoding Compressed where
       '1' -> Compressed <$> smpP
       x -> fail $ "unknown Compressed tag: " <> show x
 
--- | Compress as single chunk using stack-allocated context.
 compress1 :: ByteString -> Compressed
 compress1 bs
   | B.length bs <= maxLengthPassthrough = Passthrough bs
   | otherwise = Compressed . Large $ Z1.compress compressionLevel bs
 
-type CompressCtx = (Ptr Z.CCtx, Ptr CChar, CSize)
-
-withCompressCtx :: CSize -> (CompressCtx -> IO a) -> IO a
-withCompressCtx scratchSize action =
-  bracket Z.createCCtx Z.freeCCtx $ \cctx ->
-    allocaBytes (fromIntegral scratchSize) $ \scratchPtr ->
-      action (cctx, scratchPtr, scratchSize)
-
--- | Compress bytes, falling back to Passthrough in case of some internal error.
-compress :: CompressCtx -> ByteString -> IO Compressed
-compress ctx bs = fromRight (Passthrough bs) <$> compress_ ctx bs
-
-compress_ :: CompressCtx -> ByteString -> IO (Either String Compressed)
-compress_ (cctx, scratchPtr, scratchSize) bs
-  | B.length bs <= maxLengthPassthrough = pure . Right $ Passthrough bs
-  | otherwise =
-      B.unsafeUseAsCStringLen bs $ \(sourcePtr, sourceSize) -> runExceptT $ do
-        -- should not fail, unless input buffer is too short
-        dstSize <- ExceptT $ Z.checkError $ Z.compressCCtx cctx scratchPtr scratchSize sourcePtr (fromIntegral sourceSize) compressionLevel
-        liftIO $ Compressed . Large <$> B.packCStringLen (scratchPtr, fromIntegral dstSize)
-
-type DecompressCtx = (Ptr Z.DCtx, Ptr CChar, CSize)
-
-withDecompressCtx :: Int -> (DecompressCtx -> IO a) -> IO a
-withDecompressCtx maxUnpackedSize action =
-  bracket Z.createDCtx Z.freeDCtx $ \dctx ->
-    allocaBytes maxUnpackedSize $ \scratchPtr ->
-      action (dctx, scratchPtr, fromIntegral maxUnpackedSize)
-
-decompress :: DecompressCtx -> Compressed -> IO (Either String ByteString)
-decompress (dctx, scratchPtr, scratchSize) = \case
-  Passthrough bs -> pure $ Right bs
-  Compressed (Large bs) ->
-    B.unsafeUseAsCStringLen bs $ \(sourcePtr, sourceSize) -> do
-      res <- Z.checkError $ Z.decompressDCtx dctx scratchPtr scratchSize sourcePtr (fromIntegral sourceSize)
-      forM res $ \dstSize -> B.packCStringLen (scratchPtr, fromIntegral dstSize)
-
-decompressBatch :: Int -> NonEmpty Compressed -> NonEmpty (Either String ByteString)
-decompressBatch maxUnpackedSize items = unsafePerformIO $ withDecompressCtx maxUnpackedSize $ forM items . decompress
-{-# NOINLINE decompressBatch #-} -- prevent double-evaluation under unsafePerformIO
+decompress1 :: Compressed -> Either String ByteString
+decompress1 = \case
+  Passthrough bs -> Right bs
+  Compressed (Large bs) -> case Z1.decompress bs of
+    Z1.Error e -> Left e
+    Z1.Skip -> Right mempty
+    Z1.Decompress bs' -> Right bs'

src/Simplex/Messaging/Notifications/Transport.hs

@@ -47,7 +47,7 @@ currentClientNTFVersion :: VersionNTF
 currentClientNTFVersion = VersionNTF 1
 
 currentServerNTFVersion :: VersionNTF
-currentServerNTFVersion = VersionNTF 1
+currentServerNTFVersion = VersionNTF 2
 
 supportedClientNTFVRange :: VersionRangeNTF
 supportedClientNTFVRange = mkVersionRange initialNTFVersion currentClientNTFVersion

src/Simplex/Messaging/Transport.hs

@@ -153,7 +153,7 @@ currentClientSMPRelayVersion :: VersionSMP
 currentClientSMPRelayVersion = VersionSMP 6
 
 currentServerSMPRelayVersion :: VersionSMP
-currentServerSMPRelayVersion = VersionSMP 6
+currentServerSMPRelayVersion = VersionSMP 7
 
 -- minimal supported protocol version is 4
 -- TODO remove code that supports sending commands without batching

src/Simplex/Messaging/Transport/Client.hs

@@ -19,7 +19,7 @@ module Simplex.Messaging.Transport.Client
     TransportHost (..),
     TransportHosts (..),
     TransportHosts_ (..),
-    validateCertificateChain
+    validateCertificateChain,
   )
 where
 
@@ -52,9 +52,8 @@ import Simplex.Messaging.Encoding.String
 import Simplex.Messaging.Parsers (parseAll, parseString)
 import Simplex.Messaging.Transport
 import Simplex.Messaging.Transport.KeepAlive
-import Simplex.Messaging.Util (bshow, (<$?>), catchAll, tshow)
+import Simplex.Messaging.Util (bshow, catchAll, tshow, (<$?>))
 import System.IO.Error
-import System.Timeout (timeout)
 import Text.Read (readMaybe)
 import UnliftIO.Exception (IOException)
 import qualified UnliftIO.Exception as E
@@ -139,30 +138,26 @@ runTransportClient :: Transport c => TransportClientConfig -> Maybe ByteString -
 runTransportClient = runTLSTransportClient supportedParameters Nothing
 
 runTLSTransportClient :: Transport c => T.Supported -> Maybe XS.CertificateStore -> TransportClientConfig -> Maybe ByteString -> TransportHost -> ServiceName -> Maybe C.KeyHash -> (c -> IO a) -> IO a
-runTLSTransportClient tlsParams caStore_ cfg@TransportClientConfig {socksProxy, tcpConnectTimeout, tcpKeepAlive, clientCredentials, alpn} proxyUsername host port keyHash client = do
+runTLSTransportClient tlsParams caStore_ cfg@TransportClientConfig {socksProxy, tcpKeepAlive, clientCredentials, alpn} proxyUsername host port keyHash client = do
   serverCert <- newEmptyTMVarIO
   let hostName = B.unpack $ strEncode host
       clientParams = mkTLSClientParams tlsParams caStore_ hostName port keyHash clientCredentials alpn serverCert
       connectTCP = case socksProxy of
-        Just proxy -> connectSocksClient proxy proxyUsername $ hostAddr host
+        Just proxy -> connectSocksClient proxy proxyUsername (hostAddr host)
         _ -> connectTCPClient hostName
   c <- do
     sock <- connectTCP port
     mapM_ (setSocketKeepAlive sock) tcpKeepAlive `catchAll` \e -> logError ("Error setting TCP keep-alive" <> tshow e)
     let tCfg = clientTransportConfig cfg
-    tcpConnectTimeout `timeout` connectTLS (Just hostName) tCfg clientParams sock >>= \case
-      Nothing -> do
-        close sock
-        logError "connection timed out"
-        fail "connection timed out"
-      Just tls -> do
-        chain <-
-          atomically (tryTakeTMVar serverCert) >>= \case
-            Nothing -> do
-              logError "onServerCertificate didn't fire or failed to get cert chain"
-              closeTLS tls >> error "onServerCertificate failed"
-            Just c -> pure c
-        getClientConnection tCfg chain tls
+    -- No TLS timeout to avoid failing connections via SOCKS
+    tls <- connectTLS (Just hostName) tCfg clientParams sock
+    chain <-
+      atomically (tryTakeTMVar serverCert) >>= \case
+        Nothing -> do
+          logError "onServerCertificate didn't fire or failed to get cert chain"
+          closeTLS tls >> error "onServerCertificate failed"
+        Just c -> pure c
+    getClientConnection tCfg chain tls
   client c `E.finally` closeConnection c
   where
     hostAddr = \case

tests/AgentTests/FunctionalAPITests.hs

@@ -244,7 +244,7 @@ createConnection :: AgentClient -> UserId -> Bool -> SConnectionMode c -> Maybe
 createConnection c userId enableNtfs cMode clientData = A.createConnection c userId enableNtfs cMode clientData (IKNoPQ PQSupportOn)
 
 joinConnection :: AgentClient -> UserId -> Bool -> ConnectionRequestUri c -> ConnInfo -> SubscriptionMode -> AE ConnId
-joinConnection c userId enableNtfs cReq connInfo = A.joinConnection c userId enableNtfs cReq connInfo PQSupportOn
+joinConnection c userId enableNtfs cReq connInfo = A.joinConnection c userId Nothing enableNtfs cReq connInfo PQSupportOn
 
 sendMessage :: AgentClient -> ConnId -> SMP.MsgFlags -> MsgBody -> AE AgentMsgId
 sendMessage c connId msgFlags msgBody = do
@@ -503,7 +503,7 @@ runAgentClientTest :: HasCallStack => PQSupport -> AgentClient -> AgentClient ->
 runAgentClientTest pqSupport alice@AgentClient {} bob baseId =
   runRight_ $ do
     (bobId, qInfo) <- A.createConnection alice 1 True SCMInvitation Nothing (IKNoPQ pqSupport) SMSubscribe
-    aliceId <- A.joinConnection bob 1 True qInfo "bob's connInfo" pqSupport SMSubscribe
+    aliceId <- A.joinConnection bob 1 Nothing True qInfo "bob's connInfo" pqSupport SMSubscribe
     ("", _, A.CONF confId pqSup' _ "bob's connInfo") <- get alice
     liftIO $ pqSup' `shouldBe` pqSupport
     allowConnection alice bobId confId "alice's connInfo"
@@ -630,7 +630,9 @@ runAgentClientContactTest :: HasCallStack => PQSupport -> AgentClient -> AgentCl
 runAgentClientContactTest pqSupport alice bob baseId =
   runRight_ $ do
     (_, qInfo) <- A.createConnection alice 1 True SCMContact Nothing (IKNoPQ pqSupport) SMSubscribe
-    aliceId <- A.joinConnection bob 1 True qInfo "bob's connInfo" pqSupport SMSubscribe
+    aliceId <- A.prepareConnectionToJoin bob 1 True qInfo pqSupport
+    aliceId' <- A.joinConnection bob 1 (Just aliceId) True qInfo "bob's connInfo" pqSupport SMSubscribe
+    liftIO $ aliceId' `shouldBe` aliceId
     ("", _, A.REQ invId pqSup' _ "bob's connInfo") <- get alice
     liftIO $ pqSup' `shouldBe` pqSupport
     bobId <- acceptContact alice True invId "alice's connInfo" PQSupportOn SMSubscribe
@@ -1399,7 +1401,9 @@ makeConnectionForUsers = makeConnectionForUsers_ PQSupportOn
 makeConnectionForUsers_ :: PQSupport -> AgentClient -> UserId -> AgentClient -> UserId -> ExceptT AgentErrorType IO (ConnId, ConnId)
 makeConnectionForUsers_ pqSupport alice aliceUserId bob bobUserId = do
   (bobId, qInfo) <- A.createConnection alice aliceUserId True SCMInvitation Nothing (CR.IKNoPQ pqSupport) SMSubscribe
-  aliceId <- A.joinConnection bob bobUserId True qInfo "bob's connInfo" pqSupport SMSubscribe
+  aliceId <- A.prepareConnectionToJoin bob bobUserId True qInfo pqSupport
+  aliceId' <- A.joinConnection bob bobUserId (Just aliceId) True qInfo "bob's connInfo" pqSupport SMSubscribe
+  liftIO $ aliceId' `shouldBe` aliceId
   ("", _, A.CONF confId pqSup' _ "bob's connInfo") <- get alice
   liftIO $ pqSup' `shouldBe` pqSupport
   allowConnection alice bobId confId "alice's connInfo"

tests/CoreTests/TRcvQueuesTests.hs

@@ -22,10 +22,13 @@ tRcvQueuesTests = do
   describe "connection API" $ do
     it "hasConn" hasConnTest
     it "hasConn, batch add" hasConnTestBatch
+    it "hasConn, batch idempotent" batchIdempotentTest
     it "deleteConn" deleteConnTest
   describe "session API" $ do
     it "getSessQueues" getSessQueuesTest
     it "getDelSessQueues" getDelSessQueuesTest
+  describe "queue transfer" $ do
+    it "getDelSessQueues-batchAddQueues preserves total length" removeSubsTest
 
 checkDataInvariant :: RQ.TRcvQueues -> IO Bool
 checkDataInvariant trq = atomically $ do
@@ -62,6 +65,19 @@ hasConnTestBatch = do
   atomically (RQ.hasConn "c3" trq) `shouldReturn` True
   atomically (RQ.hasConn "nope" trq) `shouldReturn` False
 
+batchIdempotentTest :: IO ()
+batchIdempotentTest = do
+  trq <- atomically RQ.empty
+  let qs = [dummyRQ 0 "smp://1234-w==@alpha" "c1", dummyRQ 0 "smp://1234-w==@alpha" "c2", dummyRQ 0 "smp://1234-w==@beta" "c3"]
+  atomically $ RQ.batchAddQueues trq qs
+  checkDataInvariant trq `shouldReturn` True
+  qs' <- readTVarIO $ RQ.getRcvQueues trq
+  cs' <- readTVarIO $ RQ.getConnections trq
+  atomically $ RQ.batchAddQueues trq qs
+  checkDataInvariant trq `shouldReturn` True
+  readTVarIO (RQ.getRcvQueues trq) `shouldReturn` qs'
+  fmap L.nub <$> readTVarIO (RQ.getConnections trq) `shouldReturn`cs' -- connections get duplicated, but that doesn't appear to affect anybody
+
 deleteConnTest :: IO ()
 deleteConnTest = do
   trq <- atomically RQ.empty
@@ -121,6 +137,40 @@ getDelSessQueuesTest = do
   atomically (RQ.hasConn "c3" trq) `shouldReturn` True
   atomically (RQ.hasConn "c4" trq) `shouldReturn` True
 
+removeSubsTest :: IO ()
+removeSubsTest = do
+  aq <- atomically RQ.empty
+  let qs =
+        [ dummyRQ 0 "smp://1234-w==@alpha" "c1",
+          dummyRQ 0 "smp://1234-w==@alpha" "c2",
+          dummyRQ 0 "smp://1234-w==@beta" "c3",
+          dummyRQ 1 "smp://1234-w==@beta" "c4"
+        ]
+  atomically $ RQ.batchAddQueues aq qs
+
+  pq <- atomically RQ.empty
+  atomically (totalSize aq pq) `shouldReturn` (4, 4)
+
+  atomically $ RQ.getDelSessQueues (0, "smp://1234-w==@alpha", Nothing) aq >>= RQ.batchAddQueues pq . fst
+  atomically (totalSize aq pq) `shouldReturn` (4, 4)
+
+  atomically $ RQ.getDelSessQueues (0, "smp://1234-w==@beta", Just "non-existent") aq >>= RQ.batchAddQueues pq . fst
+  atomically (totalSize aq pq) `shouldReturn` (4, 4)
+
+  atomically $ RQ.getDelSessQueues (0, "smp://1234-w==@localhost", Nothing) aq >>= RQ.batchAddQueues pq . fst
+  atomically (totalSize aq pq) `shouldReturn` (4, 4)
+
+  atomically $ RQ.getDelSessQueues (0, "smp://1234-w==@beta", Just "c3") aq >>= RQ.batchAddQueues pq . fst
+  atomically (totalSize aq pq) `shouldReturn` (4, 4)
+
+totalSize :: RQ.TRcvQueues -> RQ.TRcvQueues -> STM (Int, Int)
+totalSize a b = do
+  qsizeA <- M.size <$> readTVar (RQ.getRcvQueues a)
+  qsizeB <- M.size <$> readTVar (RQ.getRcvQueues b)
+  csizeA <- M.size <$> readTVar (RQ.getConnections a)
+  csizeB <- M.size <$> readTVar (RQ.getConnections b)
+  pure (qsizeA + qsizeB, csizeA + csizeB)
+
 dummyRQ :: UserId -> SMPServer -> ConnId -> RcvQueue
 dummyRQ userId server connId =
   RcvQueue