Fix infinite loop on blocked stream

Author: splitice

src/quic/session.cc

@@ -2209,8 +2209,11 @@ void Session::StreamDataBlocked(stream_id id) {
   IncrementStat(&SessionStats::block_count);
 
   BaseObjectPtr<Stream> stream = FindStream(id);
-  if (stream)
+  if (stream) {
       stream->OnBlocked();
+  } else {
+    Debug(this, "Stream %" PRId64 " not found to block", id);
+  }
 }
 
 void Session::IncrementConnectionCloseAttempts() {
@@ -3268,26 +3271,34 @@ bool Session::Application::SendPendingData() {
   uint8_t* pos = nullptr;
   size_t packets_sent = 0;
   int err;
+  std::vector<stream_id> blocking;
+  bool ret = false;
+  BaseObjectPtr<Stream> stream;
 
   Debug(session(), "Start sending pending data");
   for (;;) {
-    ssize_t ndatalen;
     StreamData stream_data;
+    ssize_t ndatalen = 0;
     err = GetStreamData(&stream_data);
     if (err < 0) {
       session()->set_last_error(kQuicInternalError);
-      return false;
+      goto end;
     }
 
     // If the packet was sent previously, then packet will have been reset.
     if (!pos) {
       packet = CreateStreamDataPacket();
+      if (!packet) {
+        Debug(session(), "Failed to create packet for stream data");
+        session()->set_last_error(kQuicInternalError);
+        goto end;
+      }
       pos = packet->data();
     }
 
     // If stream_data.id is -1, then we're not serializing any data for any
     // specific stream. We still need to process QUIC session packets tho.
-    if (stream_data.id > -1) {
+    if (stream_data.id >= 0) {
       Debug(session(), "Serializing packets for stream id %" PRId64,
             stream_data.id);
       packet->AddRetained(stream_data.stream->GetOutboundSource());
@@ -3322,10 +3333,11 @@ bool Session::Application::SendPendingData() {
           // CONNECTION_CLOSE since even those require a
           // packet number.
           session()->Close(Session::SessionCloseFlags::SILENT);
-          return false;
+          goto end;
         case NGTCP2_ERR_STREAM_DATA_BLOCKED:
-          Debug(session(), "Stream %lld blocked", stream_data.id);
+          Debug(session(), "Stream %lld blocked session data left %lld", stream_data.id, session()->max_data_left());
           session()->StreamDataBlocked(stream_data.id);
+          blocking.push_back(stream_data.id);
           if (session()->max_data_left() == 0) {
             if (stream_data.id >= 0) {
               Debug(session(), "Resuming %llu after block", stream_data.id);
@@ -3344,6 +3356,7 @@ bool Session::Application::SendPendingData() {
           CHECK_LE(ndatalen, 0);
           continue;
         case NGTCP2_ERR_STREAM_NOT_FOUND:
+          Debug(session(), "Stream %lld no found", stream_data.id);
           continue;
         case NGTCP2_ERR_WRITE_MORE:
           CHECK_GT(ndatalen, 0);
@@ -3354,7 +3367,7 @@ bool Session::Application::SendPendingData() {
       if(nwrite != 0){ // -ve response i.e error
         packet.reset();
         session()->set_last_error(kQuicInternalError);
-        return false;
+        goto end;
       }
 
       // 0 bytes in this sending operation
@@ -3368,9 +3381,10 @@ bool Session::Application::SendPendingData() {
         Debug(session(), "Congestion limited, but %" PRIu64 " bytes pending",
               packet->length());
         if (!session()->SendPacket(std::move(packet), path))
-          return false;
+          goto end;
       }
-      return true;
+      ret = true;
+      goto end;
     }
 
     pos += nwrite;
@@ -3384,16 +3398,27 @@ bool Session::Application::SendPendingData() {
     Debug(session(), "Sending %" PRIu64 " bytes in serialized packet", nwrite);
     if (!session()->SendPacket(std::move(packet), path)) {
       Debug(session(), "-- Failed to send packet");
-      return false;
+      goto end;
     }
     pos = nullptr;
     if (++packets_sent == kMaxPackets) {
       Debug(session(), "-- Max packets sent");
       break;
     }
     Debug(session(), "-- Looping");
+  } // end for
+
+
+  ret = true;
+end:
+  for(stream_id id : blocking) {
+    stream = session()->FindStream(id);
+    if (stream) {
+      stream->Unblock();
+    }
   }
-  return true;
+
+  return ret;
 }
 
 void Session::Application::StreamClose(
@@ -3576,13 +3601,24 @@ bool DefaultApplication::ReceiveStreamData(
 }
 
 int DefaultApplication::GetStreamData(StreamData* stream_data) {
+  if (stream_queue_.IsEmpty()) {
+    stream_data->id = -1;
+    return 0;
+  }
+
   Stream* stream = stream_queue_.PopFront();
-  stream_data->stream.reset(stream);
   if (stream == nullptr) {
     stream_data->id = -1;
     return 0;
   }
   CHECK(!stream->is_destroyed());
+  stream_data->stream.reset(stream);
+
+  if(stream->IsBlocked()){
+    stream_data->id = -1;
+    return 0;
+  }
+
   stream_data->id = stream->id();
   auto next = [&](
       int status,
@@ -3600,7 +3636,6 @@ int DefaultApplication::GetStreamData(StreamData* stream_data) {
 
     stream_data->count = count;
     if (count > 0) {
-      
       stream->Schedule(&stream_queue_);
       stream_data->remaining = get_length(data, count);
     } else {

src/quic/stream.cc

@@ -269,13 +269,23 @@ void Stream::OnBlocked() {
   HandleScope handle_scope(env()->isolate());
   Context::Scope context_scope(env()->context());
 
+  blocked = true;
+
   BaseObjectPtr<Stream> ptr(this);
   USE(state->stream_blocked_callback()->Call(
       env()->context(),
       object(),
       0, nullptr));
 }
 
+bool Stream::IsBlocked(){
+  return blocked;
+}
+
+void Stream::Unblock() {
+  blocked = false;
+}
+
 void Stream::OnReset(error_code app_error_code) {
   BindingState* state = BindingState::Get(env());
   HandleScope scope(env()->isolate());

src/quic/stream.h

@@ -193,6 +193,9 @@ class Stream final : public AsyncWrap,
   void BeginHeaders(HeadersKind kind);
 
   void OnBlocked();
+  bool IsBlocked();
+  void Unblock();
+  
   void OnReset(error_code app_error_code);
 
   void Commit(size_t ammount);
@@ -295,6 +298,7 @@ class Stream final : public AsyncWrap,
   BaseObjectPtr<Session> session_;
   AliasedStruct<State> state_;
   stream_id id_;
+  bool blocked = false;
   bool destroyed_ = false;
   bool destroying_ = false;