quic: refactoring sendpendingdata

Refactoring SendPendingData for both default and http3
applications.

PR-URL: nodejs#275
Reviewed-By:  Anna Henningsen <[email protected]>

Author: jasnell

node.gyp

@@ -876,6 +876,7 @@
             'src/quic/node_quic_session-inl.h',
             'src/quic/node_quic_socket.h',
             'src/quic/node_quic_stream.h',
+            'src/quic/node_quic_stream-inl.h',
             'src/quic/node_quic_util.h',
             'src/quic/node_quic_util-inl.h',
             'src/quic/node_quic_state.h',

src/quic/node_quic.cc

@@ -9,7 +9,7 @@
 #include "node_quic_crypto.h"
 #include "node_quic_session-inl.h"
 #include "node_quic_socket.h"
-#include "node_quic_stream.h"
+#include "node_quic_stream-inl.h"
 #include "node_quic_state.h"
 #include "node_quic_util-inl.h"
 #include "node_sockaddr-inl.h"

src/quic/node_quic_default_application.cc

@@ -3,7 +3,7 @@
 #include "node_quic_default_application.h"
 #include "node_quic_session-inl.h"
 #include "node_quic_socket.h"
-#include "node_quic_stream.h"
+#include "node_quic_stream-inl.h"
 #include "node_quic_util-inl.h"
 #include "node_sockaddr-inl.h"
 #include <ngtcp2/ngtcp2.h>
@@ -13,16 +13,69 @@
 namespace node {
 namespace quic {
 
+namespace {
+void Consume(ngtcp2_vec** pvec, size_t* pcnt, size_t len) {
+  ngtcp2_vec* v = *pvec;
+  size_t cnt = *pcnt;
+
+  for (; cnt > 0; --cnt, ++v) {
+    if (v->len > len) {
+      v->len -= len;
+      v->base += len;
+      break;
+    }
+    len -= v->len;
+  }
+
+  *pvec = v;
+  *pcnt = cnt;
+}
+
+int IsEmpty(const ngtcp2_vec* vec, size_t cnt) {
+  size_t i;
+  for (i = 0; i < cnt && vec[i].len == 0; ++i) {}
+  return i == cnt;
+}
+}  // anonymous namespace
+
 DefaultApplication::DefaultApplication(
     QuicSession* session) :
     QuicApplication(session) {}
 
 bool DefaultApplication::Initialize() {
-  if (!needs_init())
-    return false;
-  Debug(session(), "Default QUIC Application Initialized");
-  set_init_done();
-  return true;
+  if (needs_init()) {
+    Debug(session(), "Default QUIC Application Initialized");
+    set_init_done();
+  }
+  return needs_init();
+}
+
+void DefaultApplication::ScheduleStream(int64_t stream_id) {
+  QuicStream* stream = session()->FindStream(stream_id);
+  Debug(session(), "Scheduling stream %" PRIu64, stream_id);
+  if (stream != nullptr)
+    stream->Schedule(&stream_queue_);
+}
+
+void DefaultApplication::UnscheduleStream(int64_t stream_id) {
+  QuicStream* stream = session()->FindStream(stream_id);
+  Debug(session(), "Unscheduling stream %" PRIu64, stream_id);
+  if (stream != nullptr)
+    stream->Unschedule();
+}
+
+void DefaultApplication::StreamClose(
+    int64_t stream_id,
+    uint64_t app_error_code) {
+  if (app_error_code == 0)
+    app_error_code = NGTCP2_APP_NOERROR;
+  UnscheduleStream(stream_id);
+  QuicApplication::StreamClose(stream_id, app_error_code);
+}
+
+void DefaultApplication::ResumeStream(int64_t stream_id) {
+  Debug(session(), "Stream %" PRId64 " has data to send");
+  ScheduleStream(stream_id);
 }
 
 bool DefaultApplication::ReceiveStreamData(
@@ -59,197 +112,51 @@ bool DefaultApplication::ReceiveStreamData(
   return true;
 }
 
-void DefaultApplication::AcknowledgeStreamData(
-    int64_t stream_id,
-    uint64_t offset,
-    size_t datalen) {
-  QuicStream* stream = session()->FindStream(stream_id);
-  Debug(session(), "Default QUIC Application acknowledging stream data");
-  // It's possible that the stream has already been destroyed and
-  // removed. If so, just silently ignore the ack
-  if (stream != nullptr)
-    stream->AckedDataOffset(offset, datalen);
+int DefaultApplication::GetStreamData(StreamData* stream_data) {
+  QuicStream* stream = stream_queue_.PopFront();
+  // If stream is nullptr, there are no streams with data pending.
+  if (stream == nullptr)
+    return 0;
+
+  stream_data->remaining =
+      stream->DrainInto(
+          &stream_data->data,
+          &stream_data->count,
+          MAX_VECTOR_COUNT);
+
+  stream_data->stream.reset(stream);
+  stream_data->id = stream->id();
+  stream_data->fin = stream->is_writable() ? 0 : 1;
+
+  // Schedule the stream again only if there is data to write. There
+  // might not actually be any more data to write but we can't know
+  // that yet as it depends entirely on how much data actually gets
+  // serialized by ngtcp2.
+  if (stream_data->count > 0)
+    stream->Schedule(&stream_queue_);
+
+  Debug(session(), "Selected %" PRId64 " buffers for stream %" PRId64 "%s",
+        stream_data->count,
+        stream_data->id,
+        stream_data->fin == 1 ? " (fin)" : "");
+  return 0;
 }
 
-bool DefaultApplication::SendPendingData() {
-  // Right now this iterates through the streams in the order they
-  // were created. Later, we might want to implement a prioritization
-  // scheme to allow higher priority streams to be serialized first.
-  // Prioritization is left entirely up to the application layer in QUIC.
-  // HTTP/3, for instance, drops prioritization entirely.
-  Debug(session(), "Default QUIC Application sending pending data");
-  for (const auto& stream : session()->streams()) {
-    if (!SendStreamData(stream.second.get()))
-      return false;
-
-    // Check to make sure QuicSession state did not change in this iteration
-    if (session()->is_in_draining_period() ||
-        session()->is_in_closing_period() ||
-        session()->is_destroyed()) {
-      break;
-    }
-  }
-
+bool DefaultApplication::StreamCommit(
+    StreamData* stream_data,
+    size_t datalen) {
+  CHECK(stream_data->stream);
+  stream_data->remaining -= datalen;
+  Consume(&stream_data->buf, &stream_data->count, datalen);
+  stream_data->stream->Commit(datalen);
   return true;
 }
 
-namespace {
-void Consume(ngtcp2_vec** pvec, size_t* pcnt, size_t len) {
-  ngtcp2_vec* v = *pvec;
-  size_t cnt = *pcnt;
-
-  for (; cnt > 0; --cnt, ++v) {
-    if (v->len > len) {
-      v->len -= len;
-      v->base += len;
-      break;
-    }
-    len -= v->len;
-  }
-
-  *pvec = v;
-  *pcnt = cnt;
-}
-
-int IsEmpty(const ngtcp2_vec* vec, size_t cnt) {
-  size_t i;
-  for (i = 0; i < cnt && vec[i].len == 0; ++i) {}
-  return i == cnt;
-}
-}  // anonymous namespace
-
-bool DefaultApplication::SendStreamData(QuicStream* stream) {
-  ssize_t ndatalen = 0;
-  QuicPathStorage path;
-  Debug(session(), "Default QUIC Application sending stream %" PRId64 " data",
-        stream->GetID());
-
-  std::vector<ngtcp2_vec> vec;
-
-  // remaining is the total number of bytes stored in the vector
-  // that are remaining to be serialized.
-  size_t remaining = stream->DrainInto(&vec);
-  Debug(stream, "Sending %d bytes of stream data. Still writable? %s",
-        remaining,
-        stream->is_writable() ? "yes" : "no");
-
-  // c and v are used to track the current serialization position
-  // for each iteration of the for(;;) loop below.
-  size_t c = vec.size();
-  ngtcp2_vec* v = vec.data();
-
-  // If there is no stream data and we're not sending fin,
-  // Just return without doing anything.
-  if (c == 0 && stream->is_writable()) {
-    Debug(stream, "There is no stream data to send");
-    return true;
-  }
-
-  std::unique_ptr<QuicPacket> packet = CreateStreamDataPacket();
-  size_t packet_offset = 0;
-
-  for (;;) {
-    Debug(stream, "Starting packet serialization. Remaining? %d", remaining);
-
-    // If packet was sent on the previous iteration, it will have been reset
-    if (!packet)
-      packet = CreateStreamDataPacket();
-
-    ssize_t nwrite =
-        ngtcp2_conn_writev_stream(
-            session()->connection(),
-            &path.path,
-            packet->data() + packet_offset,
-            session()->max_packet_length(),
-            &ndatalen,
-            remaining > 0 ?
-                NGTCP2_WRITE_STREAM_FLAG_MORE :
-                NGTCP2_WRITE_STREAM_FLAG_NONE,
-            stream->GetID(),
-            stream->is_writable() ? 0 : 1,
-            reinterpret_cast<const ngtcp2_vec*>(v),
-            c,
-            uv_hrtime());
-
-    if (nwrite <= 0) {
-      switch (nwrite) {
-        case 0:
-          // If zero is returned, we've hit congestion limits. We need to stop
-          // serializing data and try again later to empty the queue once the
-          // congestion window has expanded.
-          Debug(stream, "Congestion limit reached");
-          return true;
-        case NGTCP2_ERR_PKT_NUM_EXHAUSTED:
-          // There is a finite number of packets that can be sent
-          // per connection. Once those are exhausted, there's
-          // absolutely nothing we can do except immediately
-          // and silently tear down the QuicSession. This has
-          // to be silent because we can't even send a
-          // CONNECTION_CLOSE since even those require a
-          // packet number.
-          session()->SilentClose();
-          return false;
-        case NGTCP2_ERR_STREAM_DATA_BLOCKED:
-          Debug(stream, "Stream data blocked");
-          session()->StreamDataBlocked(stream->GetID());
-          return true;
-        case NGTCP2_ERR_STREAM_SHUT_WR:
-          Debug(stream, "Stream writable side is closed");
-          return true;
-        case NGTCP2_ERR_STREAM_NOT_FOUND:
-          Debug(stream, "Stream does not exist");
-          return true;
-        case NGTCP2_ERR_WRITE_STREAM_MORE:
-          if (ndatalen > 0) {
-            remaining -= ndatalen;
-            Debug(stream,
-                "%" PRIu64 " stream bytes serialized into packet. %d remaining",
-                ndatalen,
-                remaining);
-            Consume(&v, &c, ndatalen);
-            stream->Commit(ndatalen);
-            packet_offset += ndatalen;
-          }
-          continue;
-        default:
-          Debug(stream, "Error writing packet. Code %" PRIu64, nwrite);
-          session()->set_last_error(
-              QUIC_ERROR_SESSION,
-              static_cast<int>(nwrite));
-          return false;
-      }
-    }
-
-    if (ndatalen > 0) {
-      remaining -= ndatalen;
-      Debug(stream,
-            "%" PRIu64 " stream bytes serialized into packet. %d remaining",
-            ndatalen,
-            remaining);
-      Consume(&v, &c, ndatalen);
-      stream->Commit(ndatalen);
-    }
-
-    Debug(stream, "Sending %" PRIu64 " bytes in serialized packet", nwrite);
-    packet->set_length(nwrite);
-    if (!session()->SendPacket(std::move(packet), path))
-      return false;
-
-    packet.reset();
-    packet_offset = 0;
-
-    if (IsEmpty(v, c)) {
-      // fin will have been set if all of the data has been
-      // encoded in the packet and is_writable() returns false.
-      if (!stream->is_writable()) {
-        Debug(stream, "Final stream has been sent");
-        stream->set_fin_sent();
-      }
-      break;
-    }
-  }
-
-  return true;
+bool DefaultApplication::ShouldSetFin(const StreamData& stream_data) {
+  if (!stream_data.stream ||
+      !IsEmpty(stream_data.buf, stream_data.count))
+    return false;
+  return !stream_data.stream->is_writable();
 }
 
 }  // namespace quic

src/quic/node_quic_default_application.h

@@ -3,8 +3,10 @@
 
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
+#include "node_quic_stream.h"
 #include "node_quic_session.h"
 #include "node_quic_util.h"
+#include "util.h"
 #include "v8.h"
 
 namespace node {
@@ -28,17 +30,23 @@ class DefaultApplication final : public QuicApplication {
       const uint8_t* data,
       size_t datalen,
       uint64_t offset) override;
-  void AcknowledgeStreamData(
-      int64_t stream_id,
-      uint64_t offset,
-      size_t datalen) override;
 
-  bool SendPendingData() override;
-  bool SendStreamData(QuicStream* stream) override;
+  int GetStreamData(StreamData* stream_data) override;
+
+  void ResumeStream(int64_t stream_id) override;
+  void StreamClose(int64_t stream_id, uint64_t app_error_code) override;
+  bool ShouldSetFin(const StreamData& stream_data) override;
+  bool StreamCommit(StreamData* stream_data, size_t datalen) override;
 
   SET_SELF_SIZE(DefaultApplication)
   SET_MEMORY_INFO_NAME(DefaultApplication)
   SET_NO_MEMORY_INFO()
+
+ private:
+  void ScheduleStream(int64_t stream_id);
+  void UnscheduleStream(int64_t stream_id);
+
+  QuicStream::Queue stream_queue_;
 };
 
 }  // namespace quic