quic: extract transport logic from Application to Session

One small fix notably included:
- Check is_destroyed() after StreamCommit, since it calls JS callbacks
which could destroy the session.
Signed-off-by: Tim Perry <pimterry@gmail.com>
PR-URL: #64127
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: pimterry

src/quic/README.md

@@ -77,7 +77,7 @@ data channels that carry application data.
 
 Every entry point that may generate outbound data creates a
 `SendPendingDataScope`. Scopes nest — an internal depth counter ensures
-`Application::SendPendingData()` is called exactly once, when the outermost
+`Session::SendPendingData()` is called exactly once, when the outermost
 scope exits:
 
 ```cpp
@@ -218,13 +218,13 @@ Session::Receive()
 
 ```text
 SendPendingDataScope::~SendPendingDataScope()
- → Application::SendPendingData()
+ → Session::SendPendingData()
  Loop (up to max_packet_count):
- ├── GetStreamData() // pull data from next stream
- │ └── stream->Pull() // bob pull from Outbound→DataQueue
- ├── WriteVStream() // ngtcp2_conn_writev_stream()
+ ├── application().GetStreamData() // pull data from next stream
+ │ └── stream->Pull() // bob pull from Outbound→DataQueue
+ ├── WriteVStream() // ngtcp2_conn_writev_stream()
  │ encrypts, frames, paces
- ├── if ndatalen > 0: StreamCommit()
+ ├── if ndatalen > 0: application().StreamCommit()
  │ stream->Commit(datalen, fin)
  ├── if nwrite > 0: Send() // uv_udp_send()
  ├── if WRITE_MORE: continue // room for more in this packet

src/quic/application.cc

@@ -205,10 +205,6 @@ class Session::Application : public MemoryRetainer {
 returnfalse;
  }
 
-// Signals to the Application that it should serialize and transmit any
-// pending session and stream packets it has accumulated.
-voidSendPendingData();
-
 // Returns true if the application protocol supports sending and
 // receiving headers on streams (e.g. HTTP/3). Applications that
 // do not support headers should return false (the default).
@@ -243,10 +239,6 @@ class Session::Application : public MemoryRetainer {
 return {StreamPriority::DEFAULT, StreamPriorityFlags::NON_INCREMENTAL};
  }
 
-// The StreamData struct is used by the application to pass pending stream
-// data to the session for transmission.
-structStreamData;
-
 virtualintGetStreamData(StreamData* data) = 0;
 virtualboolStreamCommit(StreamData* data, size_t datalen) = 0;
 
@@ -262,57 +254,9 @@ class Session::Application : public MemoryRetainer {
  }
 
 private:
- Packet::Ptr CreateStreamDataPacket();
-
-// Tries to pack a pending datagram into the current packet buffer.
-// If < 0 is returned, either NGTCP2_ERR_WRITE_MORE or a fatal error is
-// returned; the caller must check. If > 0 is returned, the packet is done
-// and the value is the size of the finalized packet. If 0 is returned,
-// the datagram is either congestion limited or was abandoned
-ssize_tTryWritePendingDatagram(PathStorage* path,
-uint8_t* dest,
-size_t destlen,
-uint64_t ts);
-
-// Write the given stream_data into the buffer. The PacketInfo out-param
-// is populated by ngtcp2 with per-packet metadata (e.g., ECN codepoint)
-// that should be applied when sending the packet.
-ssize_tWriteVStream(PathStorage* path,
- PacketInfo* pi,
-uint8_t* buf,
-ssize_t* ndatalen,
-size_t max_packet_size,
-const StreamData& stream_data,
-uint64_t ts);
-
  Session* session_ = nullptr;
 };
 
-structSession::Application::StreamData final {
-// The actual number of vectors in the struct, up to kMaxVectorCount.
-size_t count = 0;
-// The stream identifier. If this is a negative value then no stream is
-// identified.
- stream_id id = -1;
-int fin = 0;
- ngtcp2_vec data[kMaxVectorCount]{};
- BaseObjectPtr<Stream> stream;
-
-static_assert(sizeof(ngtcp2_vec) == sizeof(nghttp3_vec) &&
-alignof(ngtcp2_vec) == alignof(nghttp3_vec) &&
-offsetof(ngtcp2_vec, base) == offsetof(nghttp3_vec, base) &&
-offsetof(ngtcp2_vec, len) == offsetof(nghttp3_vec, len),
-"ngtcp2_vec and nghttp3_vec must have identical layout");
-inlineoperator nghttp3_vec*() {
-returnreinterpret_cast<nghttp3_vec*>(data);
- }
-
-inlineoperatorconst ngtcp2_vec*() const { return data; }
-inlineoperator ngtcp2_vec*() { return data; }
-
- std::string ToString() const;
-};
-
 // Create a DefaultApplication for the given session.
 std::unique_ptr<Session::Application> CreateDefaultApplication(
  Session* session, const Session::Application_Options& options);

src/quic/application.h

@@ -209,24 +209,25 @@ class Http3ApplicationImpl final : public Session::Application {
  started_ = true;
 Debug(&session(), "Starting HTTP/3 application.");
 
-auto params = ngtcp2_conn_get_remote_transport_params(session());
-if (params == nullptr) [[unlikely]] {
+constauto params = session().remote_transport_params();
+if (!params) [[unlikely]] {
 // The params are not available yet. Cannot start.
 Debug(&session(),
 "Cannot start HTTP/3 application yet. No remote transport params");
 returnfalse;
  }
 
-if (params->initial_max_streams_uni < 3) {
+if (params.initial_max_streams_uni() < 3) {
 // HTTP3 requires 3 unidirectional control streams to be opened in each
 // direction in additional to the bidirectional streams that are used to
 // actually carry request and response payload back and forth.
 // See:
 // https://nghttp2.org/nghttp3/programmers-guide.html#binding-control-streams
 Debug(&session(),
 "Cannot start HTTP/3 application. Initial max "
-"unidirectional streams [%zu] is too low. Must be at least 3",
- params->initial_max_streams_uni);
+"unidirectional streams [%" PRIu64
+"] is too low. Must be at least 3",
+ params.initial_max_streams_uni());
 returnfalse;
  }
 
@@ -235,17 +236,14 @@ class Http3ApplicationImpl final : public Session::Application {
 // of requests that the client can actually created.
 if (session().is_server()) {
 nghttp3_conn_set_max_client_streams_bidi(
- *this, params->initial_max_streams_bidi);
+ *this, params.initial_max_streams_bidi());
  }
 
 Debug(&session(), "Creating and binding HTTP/3 control streams");
 bool ret =
-ngtcp2_conn_open_uni_stream(session(), &control_stream_id_, nullptr) ==
-0 &&
-ngtcp2_conn_open_uni_stream(
-session(), &qpack_enc_stream_id_, nullptr) == 0 &&
-ngtcp2_conn_open_uni_stream(
-session(), &qpack_dec_stream_id_, nullptr) == 0 &&
+session().OpenUnidirectionalStream(&control_stream_id_) &&
+session().OpenUnidirectionalStream(&qpack_enc_stream_id_) &&
+session().OpenUnidirectionalStream(&qpack_dec_stream_id_) &&
 nghttp3_conn_bind_control_stream(*this, control_stream_id_) == 0 &&
 nghttp3_conn_bind_qpack_streams(
  *this, qpack_enc_stream_id_, qpack_dec_stream_id_) == 0;
@@ -306,8 +304,7 @@ class Http3ApplicationImpl final : public Session::Application {
 Debug(&session(),
 "Extending stream and connection offset by %zd bytes",
  nread);
-session().ExtendStreamOffset(id, nread);
-session().ExtendOffset(nread);
+session().Consume(id, nread);
  }
 
 // If this data arrived as 0-RTT, mark the stream. We set it after
@@ -365,24 +362,11 @@ class Http3ApplicationImpl final : public Session::Application {
 case EndpointLabel::LOCAL:
 return;
 case EndpointLabel::REMOTE: {
-switch (direction) {
-case Direction::BIDIRECTIONAL: {
-Debug(&session(),
-"HTTP/3 application extending max bidi streams by %" PRIu64,
- max_streams);
-ngtcp2_conn_extend_max_streams_bidi(
-session(), static_cast<size_t>(max_streams));
-break;
- }
-case Direction::UNIDIRECTIONAL: {
-Debug(&session(),
-"HTTP/3 application extending max uni streams by %" PRIu64,
- max_streams);
-ngtcp2_conn_extend_max_streams_uni(
-session(), static_cast<size_t>(max_streams));
-break;
- }
- }
+Debug(&session(),
+"HTTP/3 application extending max %s streams by %" PRIu64,
+ direction == Direction::BIDIRECTIONAL ? "bidi" : "uni",
+ max_streams);
+session().ExtendMaxStreams(direction, max_streams);
  }
  }
  }
@@ -530,8 +514,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return;
  }
 
-session().SetLastError(
-QuicError::ForApplication(nghttp3_err_infer_quic_app_error_code(rv)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(rv));
 session().Close();
  }
 
@@ -548,8 +531,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return;
  }
 
-session().SetLastError(
-QuicError::ForApplication(nghttp3_err_infer_quic_app_error_code(rv)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(rv));
 session().Close();
  }
 
@@ -687,17 +669,30 @@ class Http3ApplicationImpl final : public Session::Application {
 return {StreamPriority::DEFAULT, StreamPriorityFlags::NON_INCREMENTAL};
  }
 
-intGetStreamData(StreamData* data) override {
+intGetStreamData(Session::StreamData* data) override {
+static_assert(
+sizeof(ngtcp2_vec) == sizeof(nghttp3_vec) &&
+alignof(ngtcp2_vec) == alignof(nghttp3_vec) &&
+offsetof(ngtcp2_vec, base) == offsetof(nghttp3_vec, base) &&
+offsetof(ngtcp2_vec, len) == offsetof(nghttp3_vec, len),
+"ngtcp2_vec and nghttp3_vec must have identical layout");
  data->count = kMaxVectorCount;
 ssize_t ret = 0;
 Debug(&session(), "HTTP/3 application getting stream data");
 if (conn_ && session().max_data_left()) {
- ret = nghttp3_conn_writev_stream(
- *this, &data->id, &data->fin, *data, data->count);
+// nghttp3 reports fin through an int out-param; bridge it to the bool.
+int fin = 0;
+ ret =
+nghttp3_conn_writev_stream(*this,
+ &data->id,
+ &fin,
+reinterpret_cast<nghttp3_vec*>(data->data),
+ data->count);
 // A negative return value indicates an error.
 if (ret < 0) {
 returnstatic_cast<int>(ret);
  }
+ data->fin = fin != 0;
 
  data->count = static_cast<size_t>(ret);
 if (data->id >= 0 && data->id != control_stream_id_ &&
@@ -710,7 +705,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return0;
  }
 
-boolStreamCommit(StreamData* data, size_t datalen) override {
+boolStreamCommit(Session::StreamData* data, size_t datalen) override {
 Debug(&session(),
 "HTTP/3 application committing stream %" PRIi64 " data %zu",
  data->id,
@@ -720,8 +715,7 @@ class Http3ApplicationImpl final : public Session::Application {
 // nghttp3 tracks its own offset via add_write_offset.
 int err = nghttp3_conn_add_write_offset(*this, data->id, datalen);
 if (err != 0) {
-session().SetLastError(QuicError::ForApplication(
-nghttp3_err_infer_quic_app_error_code(err)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(err));
 returnfalse;
  }
 // Raw application bytes are committed to the stream's outbound
@@ -1212,10 +1206,10 @@ class Http3ApplicationImpl final : public Session::Application {
 void* conn_user_data,
 void* stream_user_data) {
 NGHTTP3_CALLBACK_SCOPE(app);
-auto& session = app.session();
-Debug(&session, "HTTP/3 application deferred consume %zu bytes", consumed);
-session.ExtendStreamOffset(id, consumed);
- session.ExtendOffset(consumed);
+Debug(&app.session(),
+"HTTP/3 application deferred consume %zu bytes",
+ consumed);
+app.session().Consume(id, consumed);
 returnNGTCP2_SUCCESS;
  }
 

src/quic/http3.cc

@@ -77,7 +77,7 @@ data channels that carry application data.
 
 Every entry point that may generate outbound data creates a
 `SendPendingDataScope`. Scopes nest — an internal depth counter ensures
-`Application::SendPendingData()` is called exactly once, when the outermost
+`Session::SendPendingData()` is called exactly once, when the outermost
 scope exits:
 
 ```cpp
@@ -218,13 +218,13 @@ Session::Receive()
 
 ```text
 SendPendingDataScope::~SendPendingDataScope()
- → Application::SendPendingData()
+ → Session::SendPendingData()
  Loop (up to max_packet_count):
- ├── GetStreamData() // pull data from next stream
- │ └── stream->Pull() // bob pull from Outbound→DataQueue
- ├── WriteVStream() // ngtcp2_conn_writev_stream()
+ ├── application().GetStreamData() // pull data from next stream
+ │ └── stream->Pull() // bob pull from Outbound→DataQueue
+ ├── WriteVStream() // ngtcp2_conn_writev_stream()
  │ encrypts, frames, paces
- ├── if ndatalen > 0: StreamCommit()
+ ├── if ndatalen > 0: application().StreamCommit()
  │ stream->Commit(datalen, fin)
  ├── if nwrite > 0: Send() // uv_udp_send()
  ├── if WRITE_MORE: continue // room for more in this packet

src/quic/README.md

@@ -205,10 +205,6 @@ class Session::Application : public MemoryRetainer {
 returnfalse;
  }
 
-// Signals to the Application that it should serialize and transmit any
-// pending session and stream packets it has accumulated.
-voidSendPendingData();
-
 // Returns true if the application protocol supports sending and
 // receiving headers on streams (e.g. HTTP/3). Applications that
 // do not support headers should return false (the default).
@@ -243,10 +239,6 @@ class Session::Application : public MemoryRetainer {
 return {StreamPriority::DEFAULT, StreamPriorityFlags::NON_INCREMENTAL};
  }
 
-// The StreamData struct is used by the application to pass pending stream
-// data to the session for transmission.
-structStreamData;
-
 virtualintGetStreamData(StreamData* data) = 0;
 virtualboolStreamCommit(StreamData* data, size_t datalen) = 0;
 
@@ -262,57 +254,9 @@ class Session::Application : public MemoryRetainer {
  }
 
 private:
- Packet::Ptr CreateStreamDataPacket();
-
-// Tries to pack a pending datagram into the current packet buffer.
-// If < 0 is returned, either NGTCP2_ERR_WRITE_MORE or a fatal error is
-// returned; the caller must check. If > 0 is returned, the packet is done
-// and the value is the size of the finalized packet. If 0 is returned,
-// the datagram is either congestion limited or was abandoned
-ssize_tTryWritePendingDatagram(PathStorage* path,
-uint8_t* dest,
-size_t destlen,
-uint64_t ts);
-
-// Write the given stream_data into the buffer. The PacketInfo out-param
-// is populated by ngtcp2 with per-packet metadata (e.g., ECN codepoint)
-// that should be applied when sending the packet.
-ssize_tWriteVStream(PathStorage* path,
- PacketInfo* pi,
-uint8_t* buf,
-ssize_t* ndatalen,
-size_t max_packet_size,
-const StreamData& stream_data,
-uint64_t ts);
-
  Session* session_ = nullptr;
 };
 
-structSession::Application::StreamData final {
-// The actual number of vectors in the struct, up to kMaxVectorCount.
-size_t count = 0;
-// The stream identifier. If this is a negative value then no stream is
-// identified.
- stream_id id = -1;
-int fin = 0;
- ngtcp2_vec data[kMaxVectorCount]{};
- BaseObjectPtr<Stream> stream;
-
-static_assert(sizeof(ngtcp2_vec) == sizeof(nghttp3_vec) &&
-alignof(ngtcp2_vec) == alignof(nghttp3_vec) &&
-offsetof(ngtcp2_vec, base) == offsetof(nghttp3_vec, base) &&
-offsetof(ngtcp2_vec, len) == offsetof(nghttp3_vec, len),
-"ngtcp2_vec and nghttp3_vec must have identical layout");
-inlineoperator nghttp3_vec*() {
-returnreinterpret_cast<nghttp3_vec*>(data);
- }
-
-inlineoperatorconst ngtcp2_vec*() const { return data; }
-inlineoperator ngtcp2_vec*() { return data; }
-
- std::string ToString() const;
-};
-
 // Create a DefaultApplication for the given session.
 std::unique_ptr<Session::Application> CreateDefaultApplication(
  Session* session, const Session::Application_Options& options);

src/quic/application.cc

@@ -209,24 +209,25 @@ class Http3ApplicationImpl final : public Session::Application {
  started_ = true;
 Debug(&session(), "Starting HTTP/3 application.");
 
-auto params = ngtcp2_conn_get_remote_transport_params(session());
-if (params == nullptr) [[unlikely]] {
+constauto params = session().remote_transport_params();
+if (!params) [[unlikely]] {
 // The params are not available yet. Cannot start.
 Debug(&session(),
 "Cannot start HTTP/3 application yet. No remote transport params");
 returnfalse;
  }
 
-if (params->initial_max_streams_uni < 3) {
+if (params.initial_max_streams_uni() < 3) {
 // HTTP3 requires 3 unidirectional control streams to be opened in each
 // direction in additional to the bidirectional streams that are used to
 // actually carry request and response payload back and forth.
 // See:
 // https://nghttp2.org/nghttp3/programmers-guide.html#binding-control-streams
 Debug(&session(),
 "Cannot start HTTP/3 application. Initial max "
-"unidirectional streams [%zu] is too low. Must be at least 3",
- params->initial_max_streams_uni);
+"unidirectional streams [%" PRIu64
+"] is too low. Must be at least 3",
+ params.initial_max_streams_uni());
 returnfalse;
  }
 
@@ -235,17 +236,14 @@ class Http3ApplicationImpl final : public Session::Application {
 // of requests that the client can actually created.
 if (session().is_server()) {
 nghttp3_conn_set_max_client_streams_bidi(
- *this, params->initial_max_streams_bidi);
+ *this, params.initial_max_streams_bidi());
  }
 
 Debug(&session(), "Creating and binding HTTP/3 control streams");
 bool ret =
-ngtcp2_conn_open_uni_stream(session(), &control_stream_id_, nullptr) ==
-0 &&
-ngtcp2_conn_open_uni_stream(
-session(), &qpack_enc_stream_id_, nullptr) == 0 &&
-ngtcp2_conn_open_uni_stream(
-session(), &qpack_dec_stream_id_, nullptr) == 0 &&
+session().OpenUnidirectionalStream(&control_stream_id_) &&
+session().OpenUnidirectionalStream(&qpack_enc_stream_id_) &&
+session().OpenUnidirectionalStream(&qpack_dec_stream_id_) &&
 nghttp3_conn_bind_control_stream(*this, control_stream_id_) == 0 &&
 nghttp3_conn_bind_qpack_streams(
  *this, qpack_enc_stream_id_, qpack_dec_stream_id_) == 0;
@@ -306,8 +304,7 @@ class Http3ApplicationImpl final : public Session::Application {
 Debug(&session(),
 "Extending stream and connection offset by %zd bytes",
  nread);
-session().ExtendStreamOffset(id, nread);
-session().ExtendOffset(nread);
+session().Consume(id, nread);
  }
 
 // If this data arrived as 0-RTT, mark the stream. We set it after
@@ -365,24 +362,11 @@ class Http3ApplicationImpl final : public Session::Application {
 case EndpointLabel::LOCAL:
 return;
 case EndpointLabel::REMOTE: {
-switch (direction) {
-case Direction::BIDIRECTIONAL: {
-Debug(&session(),
-"HTTP/3 application extending max bidi streams by %" PRIu64,
- max_streams);
-ngtcp2_conn_extend_max_streams_bidi(
-session(), static_cast<size_t>(max_streams));
-break;
- }
-case Direction::UNIDIRECTIONAL: {
-Debug(&session(),
-"HTTP/3 application extending max uni streams by %" PRIu64,
- max_streams);
-ngtcp2_conn_extend_max_streams_uni(
-session(), static_cast<size_t>(max_streams));
-break;
- }
- }
+Debug(&session(),
+"HTTP/3 application extending max %s streams by %" PRIu64,
+ direction == Direction::BIDIRECTIONAL ? "bidi" : "uni",
+ max_streams);
+session().ExtendMaxStreams(direction, max_streams);
  }
  }
  }
@@ -530,8 +514,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return;
  }
 
-session().SetLastError(
-QuicError::ForApplication(nghttp3_err_infer_quic_app_error_code(rv)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(rv));
 session().Close();
  }
 
@@ -548,8 +531,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return;
  }
 
-session().SetLastError(
-QuicError::ForApplication(nghttp3_err_infer_quic_app_error_code(rv)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(rv));
 session().Close();
  }
 
@@ -687,17 +669,30 @@ class Http3ApplicationImpl final : public Session::Application {
 return {StreamPriority::DEFAULT, StreamPriorityFlags::NON_INCREMENTAL};
  }
 
-intGetStreamData(StreamData* data) override {
+intGetStreamData(Session::StreamData* data) override {
+static_assert(
+sizeof(ngtcp2_vec) == sizeof(nghttp3_vec) &&
+alignof(ngtcp2_vec) == alignof(nghttp3_vec) &&
+offsetof(ngtcp2_vec, base) == offsetof(nghttp3_vec, base) &&
+offsetof(ngtcp2_vec, len) == offsetof(nghttp3_vec, len),
+"ngtcp2_vec and nghttp3_vec must have identical layout");
  data->count = kMaxVectorCount;
 ssize_t ret = 0;
 Debug(&session(), "HTTP/3 application getting stream data");
 if (conn_ && session().max_data_left()) {
- ret = nghttp3_conn_writev_stream(
- *this, &data->id, &data->fin, *data, data->count);
+// nghttp3 reports fin through an int out-param; bridge it to the bool.
+int fin = 0;
+ ret =
+nghttp3_conn_writev_stream(*this,
+ &data->id,
+ &fin,
+reinterpret_cast<nghttp3_vec*>(data->data),
+ data->count);
 // A negative return value indicates an error.
 if (ret < 0) {
 returnstatic_cast<int>(ret);
  }
+ data->fin = fin != 0;
 
  data->count = static_cast<size_t>(ret);
 if (data->id >= 0 && data->id != control_stream_id_ &&
@@ -710,7 +705,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return0;
  }
 
-boolStreamCommit(StreamData* data, size_t datalen) override {
+boolStreamCommit(Session::StreamData* data, size_t datalen) override {
 Debug(&session(),
 "HTTP/3 application committing stream %" PRIi64 " data %zu",
  data->id,
@@ -720,8 +715,7 @@ class Http3ApplicationImpl final : public Session::Application {
 // nghttp3 tracks its own offset via add_write_offset.
 int err = nghttp3_conn_add_write_offset(*this, data->id, datalen);
 if (err != 0) {
-session().SetLastError(QuicError::ForApplication(
-nghttp3_err_infer_quic_app_error_code(err)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(err));
 returnfalse;
  }
 // Raw application bytes are committed to the stream's outbound
@@ -1212,10 +1206,10 @@ class Http3ApplicationImpl final : public Session::Application {
 void* conn_user_data,
 void* stream_user_data) {
 NGHTTP3_CALLBACK_SCOPE(app);
-auto& session = app.session();
-Debug(&session, "HTTP/3 application deferred consume %zu bytes", consumed);
-session.ExtendStreamOffset(id, consumed);
- session.ExtendOffset(consumed);
+Debug(&app.session(),
+"HTTP/3 application deferred consume %zu bytes",
+ consumed);
+app.session().Consume(id, consumed);
 returnNGTCP2_SUCCESS;
  }
 

src/quic/application.h

@@ -77,7 +77,7 @@ data channels that carry application data.
 
 Every entry point that may generate outbound data creates a
 `SendPendingDataScope`. Scopes nest — an internal depth counter ensures
-`Application::SendPendingData()` is called exactly once, when the outermost
+`Session::SendPendingData()` is called exactly once, when the outermost
 scope exits:
 
 ```cpp
@@ -218,13 +218,13 @@ Session::Receive()
 
 ```text
 SendPendingDataScope::~SendPendingDataScope()
- → Application::SendPendingData()
+ → Session::SendPendingData()
  Loop (up to max_packet_count):
- ├── GetStreamData() // pull data from next stream
- │ └── stream->Pull() // bob pull from Outbound→DataQueue
- ├── WriteVStream() // ngtcp2_conn_writev_stream()
+ ├── application().GetStreamData() // pull data from next stream
+ │ └── stream->Pull() // bob pull from Outbound→DataQueue
+ ├── WriteVStream() // ngtcp2_conn_writev_stream()
  │ encrypts, frames, paces
- ├── if ndatalen > 0: StreamCommit()
+ ├── if ndatalen > 0: application().StreamCommit()
  │ stream->Commit(datalen, fin)
  ├── if nwrite > 0: Send() // uv_udp_send()
  ├── if WRITE_MORE: continue // room for more in this packet

src/quic/http3.cc

@@ -205,10 +205,6 @@ class Session::Application : public MemoryRetainer {
 returnfalse;
  }
 
-// Signals to the Application that it should serialize and transmit any
-// pending session and stream packets it has accumulated.
-voidSendPendingData();
-
 // Returns true if the application protocol supports sending and
 // receiving headers on streams (e.g. HTTP/3). Applications that
 // do not support headers should return false (the default).
@@ -243,10 +239,6 @@ class Session::Application : public MemoryRetainer {
 return {StreamPriority::DEFAULT, StreamPriorityFlags::NON_INCREMENTAL};
  }
 
-// The StreamData struct is used by the application to pass pending stream
-// data to the session for transmission.
-structStreamData;
-
 virtualintGetStreamData(StreamData* data) = 0;
 virtualboolStreamCommit(StreamData* data, size_t datalen) = 0;
 
@@ -262,57 +254,9 @@ class Session::Application : public MemoryRetainer {
  }
 
 private:
- Packet::Ptr CreateStreamDataPacket();
-
-// Tries to pack a pending datagram into the current packet buffer.
-// If < 0 is returned, either NGTCP2_ERR_WRITE_MORE or a fatal error is
-// returned; the caller must check. If > 0 is returned, the packet is done
-// and the value is the size of the finalized packet. If 0 is returned,
-// the datagram is either congestion limited or was abandoned
-ssize_tTryWritePendingDatagram(PathStorage* path,
-uint8_t* dest,
-size_t destlen,
-uint64_t ts);
-
-// Write the given stream_data into the buffer. The PacketInfo out-param
-// is populated by ngtcp2 with per-packet metadata (e.g., ECN codepoint)
-// that should be applied when sending the packet.
-ssize_tWriteVStream(PathStorage* path,
- PacketInfo* pi,
-uint8_t* buf,
-ssize_t* ndatalen,
-size_t max_packet_size,
-const StreamData& stream_data,
-uint64_t ts);
-
  Session* session_ = nullptr;
 };
 
-structSession::Application::StreamData final {
-// The actual number of vectors in the struct, up to kMaxVectorCount.
-size_t count = 0;
-// The stream identifier. If this is a negative value then no stream is
-// identified.
- stream_id id = -1;
-int fin = 0;
- ngtcp2_vec data[kMaxVectorCount]{};
- BaseObjectPtr<Stream> stream;
-
-static_assert(sizeof(ngtcp2_vec) == sizeof(nghttp3_vec) &&
-alignof(ngtcp2_vec) == alignof(nghttp3_vec) &&
-offsetof(ngtcp2_vec, base) == offsetof(nghttp3_vec, base) &&
-offsetof(ngtcp2_vec, len) == offsetof(nghttp3_vec, len),
-"ngtcp2_vec and nghttp3_vec must have identical layout");
-inlineoperator nghttp3_vec*() {
-returnreinterpret_cast<nghttp3_vec*>(data);
- }
-
-inlineoperatorconst ngtcp2_vec*() const { return data; }
-inlineoperator ngtcp2_vec*() { return data; }
-
- std::string ToString() const;
-};
-
 // Create a DefaultApplication for the given session.
 std::unique_ptr<Session::Application> CreateDefaultApplication(
  Session* session, const Session::Application_Options& options);

src/quic/README.md

@@ -209,24 +209,25 @@ class Http3ApplicationImpl final : public Session::Application {
  started_ = true;
 Debug(&session(), "Starting HTTP/3 application.");
 
-auto params = ngtcp2_conn_get_remote_transport_params(session());
-if (params == nullptr) [[unlikely]] {
+constauto params = session().remote_transport_params();
+if (!params) [[unlikely]] {
 // The params are not available yet. Cannot start.
 Debug(&session(),
 "Cannot start HTTP/3 application yet. No remote transport params");
 returnfalse;
  }
 
-if (params->initial_max_streams_uni < 3) {
+if (params.initial_max_streams_uni() < 3) {
 // HTTP3 requires 3 unidirectional control streams to be opened in each
 // direction in additional to the bidirectional streams that are used to
 // actually carry request and response payload back and forth.
 // See:
 // https://nghttp2.org/nghttp3/programmers-guide.html#binding-control-streams
 Debug(&session(),
 "Cannot start HTTP/3 application. Initial max "
-"unidirectional streams [%zu] is too low. Must be at least 3",
- params->initial_max_streams_uni);
+"unidirectional streams [%" PRIu64
+"] is too low. Must be at least 3",
+ params.initial_max_streams_uni());
 returnfalse;
  }
 
@@ -235,17 +236,14 @@ class Http3ApplicationImpl final : public Session::Application {
 // of requests that the client can actually created.
 if (session().is_server()) {
 nghttp3_conn_set_max_client_streams_bidi(
- *this, params->initial_max_streams_bidi);
+ *this, params.initial_max_streams_bidi());
  }
 
 Debug(&session(), "Creating and binding HTTP/3 control streams");
 bool ret =
-ngtcp2_conn_open_uni_stream(session(), &control_stream_id_, nullptr) ==
-0 &&
-ngtcp2_conn_open_uni_stream(
-session(), &qpack_enc_stream_id_, nullptr) == 0 &&
-ngtcp2_conn_open_uni_stream(
-session(), &qpack_dec_stream_id_, nullptr) == 0 &&
+session().OpenUnidirectionalStream(&control_stream_id_) &&
+session().OpenUnidirectionalStream(&qpack_enc_stream_id_) &&
+session().OpenUnidirectionalStream(&qpack_dec_stream_id_) &&
 nghttp3_conn_bind_control_stream(*this, control_stream_id_) == 0 &&
 nghttp3_conn_bind_qpack_streams(
  *this, qpack_enc_stream_id_, qpack_dec_stream_id_) == 0;
@@ -306,8 +304,7 @@ class Http3ApplicationImpl final : public Session::Application {
 Debug(&session(),
 "Extending stream and connection offset by %zd bytes",
  nread);
-session().ExtendStreamOffset(id, nread);
-session().ExtendOffset(nread);
+session().Consume(id, nread);
  }
 
 // If this data arrived as 0-RTT, mark the stream. We set it after
@@ -365,24 +362,11 @@ class Http3ApplicationImpl final : public Session::Application {
 case EndpointLabel::LOCAL:
 return;
 case EndpointLabel::REMOTE: {
-switch (direction) {
-case Direction::BIDIRECTIONAL: {
-Debug(&session(),
-"HTTP/3 application extending max bidi streams by %" PRIu64,
- max_streams);
-ngtcp2_conn_extend_max_streams_bidi(
-session(), static_cast<size_t>(max_streams));
-break;
- }
-case Direction::UNIDIRECTIONAL: {
-Debug(&session(),
-"HTTP/3 application extending max uni streams by %" PRIu64,
- max_streams);
-ngtcp2_conn_extend_max_streams_uni(
-session(), static_cast<size_t>(max_streams));
-break;
- }
- }
+Debug(&session(),
+"HTTP/3 application extending max %s streams by %" PRIu64,
+ direction == Direction::BIDIRECTIONAL ? "bidi" : "uni",
+ max_streams);
+session().ExtendMaxStreams(direction, max_streams);
  }
  }
  }
@@ -530,8 +514,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return;
  }
 
-session().SetLastError(
-QuicError::ForApplication(nghttp3_err_infer_quic_app_error_code(rv)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(rv));
 session().Close();
  }
 
@@ -548,8 +531,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return;
  }
 
-session().SetLastError(
-QuicError::ForApplication(nghttp3_err_infer_quic_app_error_code(rv)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(rv));
 session().Close();
  }
 
@@ -687,17 +669,30 @@ class Http3ApplicationImpl final : public Session::Application {
 return {StreamPriority::DEFAULT, StreamPriorityFlags::NON_INCREMENTAL};
  }
 
-intGetStreamData(StreamData* data) override {
+intGetStreamData(Session::StreamData* data) override {
+static_assert(
+sizeof(ngtcp2_vec) == sizeof(nghttp3_vec) &&
+alignof(ngtcp2_vec) == alignof(nghttp3_vec) &&
+offsetof(ngtcp2_vec, base) == offsetof(nghttp3_vec, base) &&
+offsetof(ngtcp2_vec, len) == offsetof(nghttp3_vec, len),
+"ngtcp2_vec and nghttp3_vec must have identical layout");
  data->count = kMaxVectorCount;
 ssize_t ret = 0;
 Debug(&session(), "HTTP/3 application getting stream data");
 if (conn_ && session().max_data_left()) {
- ret = nghttp3_conn_writev_stream(
- *this, &data->id, &data->fin, *data, data->count);
+// nghttp3 reports fin through an int out-param; bridge it to the bool.
+int fin = 0;
+ ret =
+nghttp3_conn_writev_stream(*this,
+ &data->id,
+ &fin,
+reinterpret_cast<nghttp3_vec*>(data->data),
+ data->count);
 // A negative return value indicates an error.
 if (ret < 0) {
 returnstatic_cast<int>(ret);
  }
+ data->fin = fin != 0;
 
  data->count = static_cast<size_t>(ret);
 if (data->id >= 0 && data->id != control_stream_id_ &&
@@ -710,7 +705,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return0;
  }
 
-boolStreamCommit(StreamData* data, size_t datalen) override {
+boolStreamCommit(Session::StreamData* data, size_t datalen) override {
 Debug(&session(),
 "HTTP/3 application committing stream %" PRIi64 " data %zu",
  data->id,
@@ -720,8 +715,7 @@ class Http3ApplicationImpl final : public Session::Application {
 // nghttp3 tracks its own offset via add_write_offset.
 int err = nghttp3_conn_add_write_offset(*this, data->id, datalen);
 if (err != 0) {
-session().SetLastError(QuicError::ForApplication(
-nghttp3_err_infer_quic_app_error_code(err)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(err));
 returnfalse;
  }
 // Raw application bytes are committed to the stream's outbound
@@ -1212,10 +1206,10 @@ class Http3ApplicationImpl final : public Session::Application {
 void* conn_user_data,
 void* stream_user_data) {
 NGHTTP3_CALLBACK_SCOPE(app);
-auto& session = app.session();
-Debug(&session, "HTTP/3 application deferred consume %zu bytes", consumed);
-session.ExtendStreamOffset(id, consumed);
- session.ExtendOffset(consumed);
+Debug(&app.session(),
+"HTTP/3 application deferred consume %zu bytes",
+ consumed);
+app.session().Consume(id, consumed);
 returnNGTCP2_SUCCESS;
  }
 

src/quic/application.cc

@@ -77,7 +77,7 @@ data channels that carry application data.
 
 Every entry point that may generate outbound data creates a
 `SendPendingDataScope`. Scopes nest — an internal depth counter ensures
-`Application::SendPendingData()` is called exactly once, when the outermost
+`Session::SendPendingData()` is called exactly once, when the outermost
 scope exits:
 
 ```cpp
@@ -218,13 +218,13 @@ Session::Receive()
 
 ```text
 SendPendingDataScope::~SendPendingDataScope()
- → Application::SendPendingData()
+ → Session::SendPendingData()
  Loop (up to max_packet_count):
- ├── GetStreamData() // pull data from next stream
- │ └── stream->Pull() // bob pull from Outbound→DataQueue
- ├── WriteVStream() // ngtcp2_conn_writev_stream()
+ ├── application().GetStreamData() // pull data from next stream
+ │ └── stream->Pull() // bob pull from Outbound→DataQueue
+ ├── WriteVStream() // ngtcp2_conn_writev_stream()
  │ encrypts, frames, paces
- ├── if ndatalen > 0: StreamCommit()
+ ├── if ndatalen > 0: application().StreamCommit()
  │ stream->Commit(datalen, fin)
  ├── if nwrite > 0: Send() // uv_udp_send()
  ├── if WRITE_MORE: continue // room for more in this packet

src/quic/application.h

@@ -205,10 +205,6 @@ class Session::Application : public MemoryRetainer {
 returnfalse;
  }
 
-// Signals to the Application that it should serialize and transmit any
-// pending session and stream packets it has accumulated.
-voidSendPendingData();
-
 // Returns true if the application protocol supports sending and
 // receiving headers on streams (e.g. HTTP/3). Applications that
 // do not support headers should return false (the default).
@@ -243,10 +239,6 @@ class Session::Application : public MemoryRetainer {
 return {StreamPriority::DEFAULT, StreamPriorityFlags::NON_INCREMENTAL};
  }
 
-// The StreamData struct is used by the application to pass pending stream
-// data to the session for transmission.
-structStreamData;
-
 virtualintGetStreamData(StreamData* data) = 0;
 virtualboolStreamCommit(StreamData* data, size_t datalen) = 0;
 
@@ -262,57 +254,9 @@ class Session::Application : public MemoryRetainer {
  }
 
 private:
- Packet::Ptr CreateStreamDataPacket();
-
-// Tries to pack a pending datagram into the current packet buffer.
-// If < 0 is returned, either NGTCP2_ERR_WRITE_MORE or a fatal error is
-// returned; the caller must check. If > 0 is returned, the packet is done
-// and the value is the size of the finalized packet. If 0 is returned,
-// the datagram is either congestion limited or was abandoned
-ssize_tTryWritePendingDatagram(PathStorage* path,
-uint8_t* dest,
-size_t destlen,
-uint64_t ts);
-
-// Write the given stream_data into the buffer. The PacketInfo out-param
-// is populated by ngtcp2 with per-packet metadata (e.g., ECN codepoint)
-// that should be applied when sending the packet.
-ssize_tWriteVStream(PathStorage* path,
- PacketInfo* pi,
-uint8_t* buf,
-ssize_t* ndatalen,
-size_t max_packet_size,
-const StreamData& stream_data,
-uint64_t ts);
-
  Session* session_ = nullptr;
 };
 
-structSession::Application::StreamData final {
-// The actual number of vectors in the struct, up to kMaxVectorCount.
-size_t count = 0;
-// The stream identifier. If this is a negative value then no stream is
-// identified.
- stream_id id = -1;
-int fin = 0;
- ngtcp2_vec data[kMaxVectorCount]{};
- BaseObjectPtr<Stream> stream;
-
-static_assert(sizeof(ngtcp2_vec) == sizeof(nghttp3_vec) &&
-alignof(ngtcp2_vec) == alignof(nghttp3_vec) &&
-offsetof(ngtcp2_vec, base) == offsetof(nghttp3_vec, base) &&
-offsetof(ngtcp2_vec, len) == offsetof(nghttp3_vec, len),
-"ngtcp2_vec and nghttp3_vec must have identical layout");
-inlineoperator nghttp3_vec*() {
-returnreinterpret_cast<nghttp3_vec*>(data);
- }
-
-inlineoperatorconst ngtcp2_vec*() const { return data; }
-inlineoperator ngtcp2_vec*() { return data; }
-
- std::string ToString() const;
-};
-
 // Create a DefaultApplication for the given session.
 std::unique_ptr<Session::Application> CreateDefaultApplication(
  Session* session, const Session::Application_Options& options);

src/quic/http3.cc

@@ -209,24 +209,25 @@ class Http3ApplicationImpl final : public Session::Application {
  started_ = true;
 Debug(&session(), "Starting HTTP/3 application.");
 
-auto params = ngtcp2_conn_get_remote_transport_params(session());
-if (params == nullptr) [[unlikely]] {
+constauto params = session().remote_transport_params();
+if (!params) [[unlikely]] {
 // The params are not available yet. Cannot start.
 Debug(&session(),
 "Cannot start HTTP/3 application yet. No remote transport params");
 returnfalse;
  }
 
-if (params->initial_max_streams_uni < 3) {
+if (params.initial_max_streams_uni() < 3) {
 // HTTP3 requires 3 unidirectional control streams to be opened in each
 // direction in additional to the bidirectional streams that are used to
 // actually carry request and response payload back and forth.
 // See:
 // https://nghttp2.org/nghttp3/programmers-guide.html#binding-control-streams
 Debug(&session(),
 "Cannot start HTTP/3 application. Initial max "
-"unidirectional streams [%zu] is too low. Must be at least 3",
- params->initial_max_streams_uni);
+"unidirectional streams [%" PRIu64
+"] is too low. Must be at least 3",
+ params.initial_max_streams_uni());
 returnfalse;
  }
 
@@ -235,17 +236,14 @@ class Http3ApplicationImpl final : public Session::Application {
 // of requests that the client can actually created.
 if (session().is_server()) {
 nghttp3_conn_set_max_client_streams_bidi(
- *this, params->initial_max_streams_bidi);
+ *this, params.initial_max_streams_bidi());
  }
 
 Debug(&session(), "Creating and binding HTTP/3 control streams");
 bool ret =
-ngtcp2_conn_open_uni_stream(session(), &control_stream_id_, nullptr) ==
-0 &&
-ngtcp2_conn_open_uni_stream(
-session(), &qpack_enc_stream_id_, nullptr) == 0 &&
-ngtcp2_conn_open_uni_stream(
-session(), &qpack_dec_stream_id_, nullptr) == 0 &&
+session().OpenUnidirectionalStream(&control_stream_id_) &&
+session().OpenUnidirectionalStream(&qpack_enc_stream_id_) &&
+session().OpenUnidirectionalStream(&qpack_dec_stream_id_) &&
 nghttp3_conn_bind_control_stream(*this, control_stream_id_) == 0 &&
 nghttp3_conn_bind_qpack_streams(
  *this, qpack_enc_stream_id_, qpack_dec_stream_id_) == 0;
@@ -306,8 +304,7 @@ class Http3ApplicationImpl final : public Session::Application {
 Debug(&session(),
 "Extending stream and connection offset by %zd bytes",
  nread);
-session().ExtendStreamOffset(id, nread);
-session().ExtendOffset(nread);
+session().Consume(id, nread);
  }
 
 // If this data arrived as 0-RTT, mark the stream. We set it after
@@ -365,24 +362,11 @@ class Http3ApplicationImpl final : public Session::Application {
 case EndpointLabel::LOCAL:
 return;
 case EndpointLabel::REMOTE: {
-switch (direction) {
-case Direction::BIDIRECTIONAL: {
-Debug(&session(),
-"HTTP/3 application extending max bidi streams by %" PRIu64,
- max_streams);
-ngtcp2_conn_extend_max_streams_bidi(
-session(), static_cast<size_t>(max_streams));
-break;
- }
-case Direction::UNIDIRECTIONAL: {
-Debug(&session(),
-"HTTP/3 application extending max uni streams by %" PRIu64,
- max_streams);
-ngtcp2_conn_extend_max_streams_uni(
-session(), static_cast<size_t>(max_streams));
-break;
- }
- }
+Debug(&session(),
+"HTTP/3 application extending max %s streams by %" PRIu64,
+ direction == Direction::BIDIRECTIONAL ? "bidi" : "uni",
+ max_streams);
+session().ExtendMaxStreams(direction, max_streams);
  }
  }
  }
@@ -530,8 +514,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return;
  }
 
-session().SetLastError(
-QuicError::ForApplication(nghttp3_err_infer_quic_app_error_code(rv)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(rv));
 session().Close();
  }
 
@@ -548,8 +531,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return;
  }
 
-session().SetLastError(
-QuicError::ForApplication(nghttp3_err_infer_quic_app_error_code(rv)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(rv));
 session().Close();
  }
 
@@ -687,17 +669,30 @@ class Http3ApplicationImpl final : public Session::Application {
 return {StreamPriority::DEFAULT, StreamPriorityFlags::NON_INCREMENTAL};
  }
 
-intGetStreamData(StreamData* data) override {
+intGetStreamData(Session::StreamData* data) override {
+static_assert(
+sizeof(ngtcp2_vec) == sizeof(nghttp3_vec) &&
+alignof(ngtcp2_vec) == alignof(nghttp3_vec) &&
+offsetof(ngtcp2_vec, base) == offsetof(nghttp3_vec, base) &&
+offsetof(ngtcp2_vec, len) == offsetof(nghttp3_vec, len),
+"ngtcp2_vec and nghttp3_vec must have identical layout");
  data->count = kMaxVectorCount;
 ssize_t ret = 0;
 Debug(&session(), "HTTP/3 application getting stream data");
 if (conn_ && session().max_data_left()) {
- ret = nghttp3_conn_writev_stream(
- *this, &data->id, &data->fin, *data, data->count);
+// nghttp3 reports fin through an int out-param; bridge it to the bool.
+int fin = 0;
+ ret =
+nghttp3_conn_writev_stream(*this,
+ &data->id,
+ &fin,
+reinterpret_cast<nghttp3_vec*>(data->data),
+ data->count);
 // A negative return value indicates an error.
 if (ret < 0) {
 returnstatic_cast<int>(ret);
  }
+ data->fin = fin != 0;
 
  data->count = static_cast<size_t>(ret);
 if (data->id >= 0 && data->id != control_stream_id_ &&
@@ -710,7 +705,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return0;
  }
 
-boolStreamCommit(StreamData* data, size_t datalen) override {
+boolStreamCommit(Session::StreamData* data, size_t datalen) override {
 Debug(&session(),
 "HTTP/3 application committing stream %" PRIi64 " data %zu",
  data->id,
@@ -720,8 +715,7 @@ class Http3ApplicationImpl final : public Session::Application {
 // nghttp3 tracks its own offset via add_write_offset.
 int err = nghttp3_conn_add_write_offset(*this, data->id, datalen);
 if (err != 0) {
-session().SetLastError(QuicError::ForApplication(
-nghttp3_err_infer_quic_app_error_code(err)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(err));
 returnfalse;
  }
 // Raw application bytes are committed to the stream's outbound
@@ -1212,10 +1206,10 @@ class Http3ApplicationImpl final : public Session::Application {
 void* conn_user_data,
 void* stream_user_data) {
 NGHTTP3_CALLBACK_SCOPE(app);
-auto& session = app.session();
-Debug(&session, "HTTP/3 application deferred consume %zu bytes", consumed);
-session.ExtendStreamOffset(id, consumed);
- session.ExtendOffset(consumed);
+Debug(&app.session(),
+"HTTP/3 application deferred consume %zu bytes",
+ consumed);
+app.session().Consume(id, consumed);
 returnNGTCP2_SUCCESS;
  }
 

src/quic/README.md

@@ -77,7 +77,7 @@ data channels that carry application data.
 
 Every entry point that may generate outbound data creates a
 `SendPendingDataScope`. Scopes nest — an internal depth counter ensures
-`Application::SendPendingData()` is called exactly once, when the outermost
+`Session::SendPendingData()` is called exactly once, when the outermost
 scope exits:
 
 ```cpp
@@ -218,13 +218,13 @@ Session::Receive()
 
 ```text
 SendPendingDataScope::~SendPendingDataScope()
- → Application::SendPendingData()
+ → Session::SendPendingData()
  Loop (up to max_packet_count):
- ├── GetStreamData() // pull data from next stream
- │ └── stream->Pull() // bob pull from Outbound→DataQueue
- ├── WriteVStream() // ngtcp2_conn_writev_stream()
+ ├── application().GetStreamData() // pull data from next stream
+ │ └── stream->Pull() // bob pull from Outbound→DataQueue
+ ├── WriteVStream() // ngtcp2_conn_writev_stream()
  │ encrypts, frames, paces
- ├── if ndatalen > 0: StreamCommit()
+ ├── if ndatalen > 0: application().StreamCommit()
  │ stream->Commit(datalen, fin)
  ├── if nwrite > 0: Send() // uv_udp_send()
  ├── if WRITE_MORE: continue // room for more in this packet

src/quic/application.cc

@@ -205,10 +205,6 @@ class Session::Application : public MemoryRetainer {
 returnfalse;
  }
 
-// Signals to the Application that it should serialize and transmit any
-// pending session and stream packets it has accumulated.
-voidSendPendingData();
-
 // Returns true if the application protocol supports sending and
 // receiving headers on streams (e.g. HTTP/3). Applications that
 // do not support headers should return false (the default).
@@ -243,10 +239,6 @@ class Session::Application : public MemoryRetainer {
 return {StreamPriority::DEFAULT, StreamPriorityFlags::NON_INCREMENTAL};
  }
 
-// The StreamData struct is used by the application to pass pending stream
-// data to the session for transmission.
-structStreamData;
-
 virtualintGetStreamData(StreamData* data) = 0;
 virtualboolStreamCommit(StreamData* data, size_t datalen) = 0;
 
@@ -262,57 +254,9 @@ class Session::Application : public MemoryRetainer {
  }
 
 private:
- Packet::Ptr CreateStreamDataPacket();
-
-// Tries to pack a pending datagram into the current packet buffer.
-// If < 0 is returned, either NGTCP2_ERR_WRITE_MORE or a fatal error is
-// returned; the caller must check. If > 0 is returned, the packet is done
-// and the value is the size of the finalized packet. If 0 is returned,
-// the datagram is either congestion limited or was abandoned
-ssize_tTryWritePendingDatagram(PathStorage* path,
-uint8_t* dest,
-size_t destlen,
-uint64_t ts);
-
-// Write the given stream_data into the buffer. The PacketInfo out-param
-// is populated by ngtcp2 with per-packet metadata (e.g., ECN codepoint)
-// that should be applied when sending the packet.
-ssize_tWriteVStream(PathStorage* path,
- PacketInfo* pi,
-uint8_t* buf,
-ssize_t* ndatalen,
-size_t max_packet_size,
-const StreamData& stream_data,
-uint64_t ts);
-
  Session* session_ = nullptr;
 };
 
-structSession::Application::StreamData final {
-// The actual number of vectors in the struct, up to kMaxVectorCount.
-size_t count = 0;
-// The stream identifier. If this is a negative value then no stream is
-// identified.
- stream_id id = -1;
-int fin = 0;
- ngtcp2_vec data[kMaxVectorCount]{};
- BaseObjectPtr<Stream> stream;
-
-static_assert(sizeof(ngtcp2_vec) == sizeof(nghttp3_vec) &&
-alignof(ngtcp2_vec) == alignof(nghttp3_vec) &&
-offsetof(ngtcp2_vec, base) == offsetof(nghttp3_vec, base) &&
-offsetof(ngtcp2_vec, len) == offsetof(nghttp3_vec, len),
-"ngtcp2_vec and nghttp3_vec must have identical layout");
-inlineoperator nghttp3_vec*() {
-returnreinterpret_cast<nghttp3_vec*>(data);
- }
-
-inlineoperatorconst ngtcp2_vec*() const { return data; }
-inlineoperator ngtcp2_vec*() { return data; }
-
- std::string ToString() const;
-};
-
 // Create a DefaultApplication for the given session.
 std::unique_ptr<Session::Application> CreateDefaultApplication(
  Session* session, const Session::Application_Options& options);

src/quic/application.h

@@ -209,24 +209,25 @@ class Http3ApplicationImpl final : public Session::Application {
  started_ = true;
 Debug(&session(), "Starting HTTP/3 application.");
 
-auto params = ngtcp2_conn_get_remote_transport_params(session());
-if (params == nullptr) [[unlikely]] {
+constauto params = session().remote_transport_params();
+if (!params) [[unlikely]] {
 // The params are not available yet. Cannot start.
 Debug(&session(),
 "Cannot start HTTP/3 application yet. No remote transport params");
 returnfalse;
  }
 
-if (params->initial_max_streams_uni < 3) {
+if (params.initial_max_streams_uni() < 3) {
 // HTTP3 requires 3 unidirectional control streams to be opened in each
 // direction in additional to the bidirectional streams that are used to
 // actually carry request and response payload back and forth.
 // See:
 // https://nghttp2.org/nghttp3/programmers-guide.html#binding-control-streams
 Debug(&session(),
 "Cannot start HTTP/3 application. Initial max "
-"unidirectional streams [%zu] is too low. Must be at least 3",
- params->initial_max_streams_uni);
+"unidirectional streams [%" PRIu64
+"] is too low. Must be at least 3",
+ params.initial_max_streams_uni());
 returnfalse;
  }
 
@@ -235,17 +236,14 @@ class Http3ApplicationImpl final : public Session::Application {
 // of requests that the client can actually created.
 if (session().is_server()) {
 nghttp3_conn_set_max_client_streams_bidi(
- *this, params->initial_max_streams_bidi);
+ *this, params.initial_max_streams_bidi());
  }
 
 Debug(&session(), "Creating and binding HTTP/3 control streams");
 bool ret =
-ngtcp2_conn_open_uni_stream(session(), &control_stream_id_, nullptr) ==
-0 &&
-ngtcp2_conn_open_uni_stream(
-session(), &qpack_enc_stream_id_, nullptr) == 0 &&
-ngtcp2_conn_open_uni_stream(
-session(), &qpack_dec_stream_id_, nullptr) == 0 &&
+session().OpenUnidirectionalStream(&control_stream_id_) &&
+session().OpenUnidirectionalStream(&qpack_enc_stream_id_) &&
+session().OpenUnidirectionalStream(&qpack_dec_stream_id_) &&
 nghttp3_conn_bind_control_stream(*this, control_stream_id_) == 0 &&
 nghttp3_conn_bind_qpack_streams(
  *this, qpack_enc_stream_id_, qpack_dec_stream_id_) == 0;
@@ -306,8 +304,7 @@ class Http3ApplicationImpl final : public Session::Application {
 Debug(&session(),
 "Extending stream and connection offset by %zd bytes",
  nread);
-session().ExtendStreamOffset(id, nread);
-session().ExtendOffset(nread);
+session().Consume(id, nread);
  }
 
 // If this data arrived as 0-RTT, mark the stream. We set it after
@@ -365,24 +362,11 @@ class Http3ApplicationImpl final : public Session::Application {
 case EndpointLabel::LOCAL:
 return;
 case EndpointLabel::REMOTE: {
-switch (direction) {
-case Direction::BIDIRECTIONAL: {
-Debug(&session(),
-"HTTP/3 application extending max bidi streams by %" PRIu64,
- max_streams);
-ngtcp2_conn_extend_max_streams_bidi(
-session(), static_cast<size_t>(max_streams));
-break;
- }
-case Direction::UNIDIRECTIONAL: {
-Debug(&session(),
-"HTTP/3 application extending max uni streams by %" PRIu64,
- max_streams);
-ngtcp2_conn_extend_max_streams_uni(
-session(), static_cast<size_t>(max_streams));
-break;
- }
- }
+Debug(&session(),
+"HTTP/3 application extending max %s streams by %" PRIu64,
+ direction == Direction::BIDIRECTIONAL ? "bidi" : "uni",
+ max_streams);
+session().ExtendMaxStreams(direction, max_streams);
  }
  }
  }
@@ -530,8 +514,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return;
  }
 
-session().SetLastError(
-QuicError::ForApplication(nghttp3_err_infer_quic_app_error_code(rv)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(rv));
 session().Close();
  }
 
@@ -548,8 +531,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return;
  }
 
-session().SetLastError(
-QuicError::ForApplication(nghttp3_err_infer_quic_app_error_code(rv)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(rv));
 session().Close();
  }
 
@@ -687,17 +669,30 @@ class Http3ApplicationImpl final : public Session::Application {
 return {StreamPriority::DEFAULT, StreamPriorityFlags::NON_INCREMENTAL};
  }
 
-intGetStreamData(StreamData* data) override {
+intGetStreamData(Session::StreamData* data) override {
+static_assert(
+sizeof(ngtcp2_vec) == sizeof(nghttp3_vec) &&
+alignof(ngtcp2_vec) == alignof(nghttp3_vec) &&
+offsetof(ngtcp2_vec, base) == offsetof(nghttp3_vec, base) &&
+offsetof(ngtcp2_vec, len) == offsetof(nghttp3_vec, len),
+"ngtcp2_vec and nghttp3_vec must have identical layout");
  data->count = kMaxVectorCount;
 ssize_t ret = 0;
 Debug(&session(), "HTTP/3 application getting stream data");
 if (conn_ && session().max_data_left()) {
- ret = nghttp3_conn_writev_stream(
- *this, &data->id, &data->fin, *data, data->count);
+// nghttp3 reports fin through an int out-param; bridge it to the bool.
+int fin = 0;
+ ret =
+nghttp3_conn_writev_stream(*this,
+ &data->id,
+ &fin,
+reinterpret_cast<nghttp3_vec*>(data->data),
+ data->count);
 // A negative return value indicates an error.
 if (ret < 0) {
 returnstatic_cast<int>(ret);
  }
+ data->fin = fin != 0;
 
  data->count = static_cast<size_t>(ret);
 if (data->id >= 0 && data->id != control_stream_id_ &&
@@ -710,7 +705,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return0;
  }
 
-boolStreamCommit(StreamData* data, size_t datalen) override {
+boolStreamCommit(Session::StreamData* data, size_t datalen) override {
 Debug(&session(),
 "HTTP/3 application committing stream %" PRIi64 " data %zu",
  data->id,
@@ -720,8 +715,7 @@ class Http3ApplicationImpl final : public Session::Application {
 // nghttp3 tracks its own offset via add_write_offset.
 int err = nghttp3_conn_add_write_offset(*this, data->id, datalen);
 if (err != 0) {
-session().SetLastError(QuicError::ForApplication(
-nghttp3_err_infer_quic_app_error_code(err)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(err));
 returnfalse;
  }
 // Raw application bytes are committed to the stream's outbound
@@ -1212,10 +1206,10 @@ class Http3ApplicationImpl final : public Session::Application {
 void* conn_user_data,
 void* stream_user_data) {
 NGHTTP3_CALLBACK_SCOPE(app);
-auto& session = app.session();
-Debug(&session, "HTTP/3 application deferred consume %zu bytes", consumed);
-session.ExtendStreamOffset(id, consumed);
- session.ExtendOffset(consumed);
+Debug(&app.session(),
+"HTTP/3 application deferred consume %zu bytes",
+ consumed);
+app.session().Consume(id, consumed);
 returnNGTCP2_SUCCESS;
  }
 

src/quic/http3.cc

@@ -77,7 +77,7 @@ data channels that carry application data.
 
 Every entry point that may generate outbound data creates a
 `SendPendingDataScope`. Scopes nest — an internal depth counter ensures
-`Application::SendPendingData()` is called exactly once, when the outermost
+`Session::SendPendingData()` is called exactly once, when the outermost
 scope exits:
 
 ```cpp
@@ -218,13 +218,13 @@ Session::Receive()
 
 ```text
 SendPendingDataScope::~SendPendingDataScope()
- → Application::SendPendingData()
+ → Session::SendPendingData()
  Loop (up to max_packet_count):
- ├── GetStreamData() // pull data from next stream
- │ └── stream->Pull() // bob pull from Outbound→DataQueue
- ├── WriteVStream() // ngtcp2_conn_writev_stream()
+ ├── application().GetStreamData() // pull data from next stream
+ │ └── stream->Pull() // bob pull from Outbound→DataQueue
+ ├── WriteVStream() // ngtcp2_conn_writev_stream()
  │ encrypts, frames, paces
- ├── if ndatalen > 0: StreamCommit()
+ ├── if ndatalen > 0: application().StreamCommit()
  │ stream->Commit(datalen, fin)
  ├── if nwrite > 0: Send() // uv_udp_send()
  ├── if WRITE_MORE: continue // room for more in this packet

src/quic/README.md

@@ -205,10 +205,6 @@ class Session::Application : public MemoryRetainer {
 returnfalse;
  }
 
-// Signals to the Application that it should serialize and transmit any
-// pending session and stream packets it has accumulated.
-voidSendPendingData();
-
 // Returns true if the application protocol supports sending and
 // receiving headers on streams (e.g. HTTP/3). Applications that
 // do not support headers should return false (the default).
@@ -243,10 +239,6 @@ class Session::Application : public MemoryRetainer {
 return {StreamPriority::DEFAULT, StreamPriorityFlags::NON_INCREMENTAL};
  }
 
-// The StreamData struct is used by the application to pass pending stream
-// data to the session for transmission.
-structStreamData;
-
 virtualintGetStreamData(StreamData* data) = 0;
 virtualboolStreamCommit(StreamData* data, size_t datalen) = 0;
 
@@ -262,57 +254,9 @@ class Session::Application : public MemoryRetainer {
  }
 
 private:
- Packet::Ptr CreateStreamDataPacket();
-
-// Tries to pack a pending datagram into the current packet buffer.
-// If < 0 is returned, either NGTCP2_ERR_WRITE_MORE or a fatal error is
-// returned; the caller must check. If > 0 is returned, the packet is done
-// and the value is the size of the finalized packet. If 0 is returned,
-// the datagram is either congestion limited or was abandoned
-ssize_tTryWritePendingDatagram(PathStorage* path,
-uint8_t* dest,
-size_t destlen,
-uint64_t ts);
-
-// Write the given stream_data into the buffer. The PacketInfo out-param
-// is populated by ngtcp2 with per-packet metadata (e.g., ECN codepoint)
-// that should be applied when sending the packet.
-ssize_tWriteVStream(PathStorage* path,
- PacketInfo* pi,
-uint8_t* buf,
-ssize_t* ndatalen,
-size_t max_packet_size,
-const StreamData& stream_data,
-uint64_t ts);
-
  Session* session_ = nullptr;
 };
 
-structSession::Application::StreamData final {
-// The actual number of vectors in the struct, up to kMaxVectorCount.
-size_t count = 0;
-// The stream identifier. If this is a negative value then no stream is
-// identified.
- stream_id id = -1;
-int fin = 0;
- ngtcp2_vec data[kMaxVectorCount]{};
- BaseObjectPtr<Stream> stream;
-
-static_assert(sizeof(ngtcp2_vec) == sizeof(nghttp3_vec) &&
-alignof(ngtcp2_vec) == alignof(nghttp3_vec) &&
-offsetof(ngtcp2_vec, base) == offsetof(nghttp3_vec, base) &&
-offsetof(ngtcp2_vec, len) == offsetof(nghttp3_vec, len),
-"ngtcp2_vec and nghttp3_vec must have identical layout");
-inlineoperator nghttp3_vec*() {
-returnreinterpret_cast<nghttp3_vec*>(data);
- }
-
-inlineoperatorconst ngtcp2_vec*() const { return data; }
-inlineoperator ngtcp2_vec*() { return data; }
-
- std::string ToString() const;
-};
-
 // Create a DefaultApplication for the given session.
 std::unique_ptr<Session::Application> CreateDefaultApplication(
  Session* session, const Session::Application_Options& options);

src/quic/application.cc

@@ -209,24 +209,25 @@ class Http3ApplicationImpl final : public Session::Application {
  started_ = true;
 Debug(&session(), "Starting HTTP/3 application.");
 
-auto params = ngtcp2_conn_get_remote_transport_params(session());
-if (params == nullptr) [[unlikely]] {
+constauto params = session().remote_transport_params();
+if (!params) [[unlikely]] {
 // The params are not available yet. Cannot start.
 Debug(&session(),
 "Cannot start HTTP/3 application yet. No remote transport params");
 returnfalse;
  }
 
-if (params->initial_max_streams_uni < 3) {
+if (params.initial_max_streams_uni() < 3) {
 // HTTP3 requires 3 unidirectional control streams to be opened in each
 // direction in additional to the bidirectional streams that are used to
 // actually carry request and response payload back and forth.
 // See:
 // https://nghttp2.org/nghttp3/programmers-guide.html#binding-control-streams
 Debug(&session(),
 "Cannot start HTTP/3 application. Initial max "
-"unidirectional streams [%zu] is too low. Must be at least 3",
- params->initial_max_streams_uni);
+"unidirectional streams [%" PRIu64
+"] is too low. Must be at least 3",
+ params.initial_max_streams_uni());
 returnfalse;
  }
 
@@ -235,17 +236,14 @@ class Http3ApplicationImpl final : public Session::Application {
 // of requests that the client can actually created.
 if (session().is_server()) {
 nghttp3_conn_set_max_client_streams_bidi(
- *this, params->initial_max_streams_bidi);
+ *this, params.initial_max_streams_bidi());
  }
 
 Debug(&session(), "Creating and binding HTTP/3 control streams");
 bool ret =
-ngtcp2_conn_open_uni_stream(session(), &control_stream_id_, nullptr) ==
-0 &&
-ngtcp2_conn_open_uni_stream(
-session(), &qpack_enc_stream_id_, nullptr) == 0 &&
-ngtcp2_conn_open_uni_stream(
-session(), &qpack_dec_stream_id_, nullptr) == 0 &&
+session().OpenUnidirectionalStream(&control_stream_id_) &&
+session().OpenUnidirectionalStream(&qpack_enc_stream_id_) &&
+session().OpenUnidirectionalStream(&qpack_dec_stream_id_) &&
 nghttp3_conn_bind_control_stream(*this, control_stream_id_) == 0 &&
 nghttp3_conn_bind_qpack_streams(
  *this, qpack_enc_stream_id_, qpack_dec_stream_id_) == 0;
@@ -306,8 +304,7 @@ class Http3ApplicationImpl final : public Session::Application {
 Debug(&session(),
 "Extending stream and connection offset by %zd bytes",
  nread);
-session().ExtendStreamOffset(id, nread);
-session().ExtendOffset(nread);
+session().Consume(id, nread);
  }
 
 // If this data arrived as 0-RTT, mark the stream. We set it after
@@ -365,24 +362,11 @@ class Http3ApplicationImpl final : public Session::Application {
 case EndpointLabel::LOCAL:
 return;
 case EndpointLabel::REMOTE: {
-switch (direction) {
-case Direction::BIDIRECTIONAL: {
-Debug(&session(),
-"HTTP/3 application extending max bidi streams by %" PRIu64,
- max_streams);
-ngtcp2_conn_extend_max_streams_bidi(
-session(), static_cast<size_t>(max_streams));
-break;
- }
-case Direction::UNIDIRECTIONAL: {
-Debug(&session(),
-"HTTP/3 application extending max uni streams by %" PRIu64,
- max_streams);
-ngtcp2_conn_extend_max_streams_uni(
-session(), static_cast<size_t>(max_streams));
-break;
- }
- }
+Debug(&session(),
+"HTTP/3 application extending max %s streams by %" PRIu64,
+ direction == Direction::BIDIRECTIONAL ? "bidi" : "uni",
+ max_streams);
+session().ExtendMaxStreams(direction, max_streams);
  }
  }
  }
@@ -530,8 +514,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return;
  }
 
-session().SetLastError(
-QuicError::ForApplication(nghttp3_err_infer_quic_app_error_code(rv)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(rv));
 session().Close();
  }
 
@@ -548,8 +531,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return;
  }
 
-session().SetLastError(
-QuicError::ForApplication(nghttp3_err_infer_quic_app_error_code(rv)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(rv));
 session().Close();
  }
 
@@ -687,17 +669,30 @@ class Http3ApplicationImpl final : public Session::Application {
 return {StreamPriority::DEFAULT, StreamPriorityFlags::NON_INCREMENTAL};
  }
 
-intGetStreamData(StreamData* data) override {
+intGetStreamData(Session::StreamData* data) override {
+static_assert(
+sizeof(ngtcp2_vec) == sizeof(nghttp3_vec) &&
+alignof(ngtcp2_vec) == alignof(nghttp3_vec) &&
+offsetof(ngtcp2_vec, base) == offsetof(nghttp3_vec, base) &&
+offsetof(ngtcp2_vec, len) == offsetof(nghttp3_vec, len),
+"ngtcp2_vec and nghttp3_vec must have identical layout");
  data->count = kMaxVectorCount;
 ssize_t ret = 0;
 Debug(&session(), "HTTP/3 application getting stream data");
 if (conn_ && session().max_data_left()) {
- ret = nghttp3_conn_writev_stream(
- *this, &data->id, &data->fin, *data, data->count);
+// nghttp3 reports fin through an int out-param; bridge it to the bool.
+int fin = 0;
+ ret =
+nghttp3_conn_writev_stream(*this,
+ &data->id,
+ &fin,
+reinterpret_cast<nghttp3_vec*>(data->data),
+ data->count);
 // A negative return value indicates an error.
 if (ret < 0) {
 returnstatic_cast<int>(ret);
  }
+ data->fin = fin != 0;
 
  data->count = static_cast<size_t>(ret);
 if (data->id >= 0 && data->id != control_stream_id_ &&
@@ -710,7 +705,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return0;
  }
 
-boolStreamCommit(StreamData* data, size_t datalen) override {
+boolStreamCommit(Session::StreamData* data, size_t datalen) override {
 Debug(&session(),
 "HTTP/3 application committing stream %" PRIi64 " data %zu",
  data->id,
@@ -720,8 +715,7 @@ class Http3ApplicationImpl final : public Session::Application {
 // nghttp3 tracks its own offset via add_write_offset.
 int err = nghttp3_conn_add_write_offset(*this, data->id, datalen);
 if (err != 0) {
-session().SetLastError(QuicError::ForApplication(
-nghttp3_err_infer_quic_app_error_code(err)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(err));
 returnfalse;
  }
 // Raw application bytes are committed to the stream's outbound
@@ -1212,10 +1206,10 @@ class Http3ApplicationImpl final : public Session::Application {
 void* conn_user_data,
 void* stream_user_data) {
 NGHTTP3_CALLBACK_SCOPE(app);
-auto& session = app.session();
-Debug(&session, "HTTP/3 application deferred consume %zu bytes", consumed);
-session.ExtendStreamOffset(id, consumed);
- session.ExtendOffset(consumed);
+Debug(&app.session(),
+"HTTP/3 application deferred consume %zu bytes",
+ consumed);
+app.session().Consume(id, consumed);
 returnNGTCP2_SUCCESS;
  }
 

src/quic/application.h

@@ -77,7 +77,7 @@ data channels that carry application data.
 
 Every entry point that may generate outbound data creates a
 `SendPendingDataScope`. Scopes nest — an internal depth counter ensures
-`Application::SendPendingData()` is called exactly once, when the outermost
+`Session::SendPendingData()` is called exactly once, when the outermost
 scope exits:
 
 ```cpp
@@ -218,13 +218,13 @@ Session::Receive()
 
 ```text
 SendPendingDataScope::~SendPendingDataScope()
- → Application::SendPendingData()
+ → Session::SendPendingData()
  Loop (up to max_packet_count):
- ├── GetStreamData() // pull data from next stream
- │ └── stream->Pull() // bob pull from Outbound→DataQueue
- ├── WriteVStream() // ngtcp2_conn_writev_stream()
+ ├── application().GetStreamData() // pull data from next stream
+ │ └── stream->Pull() // bob pull from Outbound→DataQueue
+ ├── WriteVStream() // ngtcp2_conn_writev_stream()
  │ encrypts, frames, paces
- ├── if ndatalen > 0: StreamCommit()
+ ├── if ndatalen > 0: application().StreamCommit()
  │ stream->Commit(datalen, fin)
  ├── if nwrite > 0: Send() // uv_udp_send()
  ├── if WRITE_MORE: continue // room for more in this packet

src/quic/http3.cc

@@ -205,10 +205,6 @@ class Session::Application : public MemoryRetainer {
 returnfalse;
  }
 
-// Signals to the Application that it should serialize and transmit any
-// pending session and stream packets it has accumulated.
-voidSendPendingData();
-
 // Returns true if the application protocol supports sending and
 // receiving headers on streams (e.g. HTTP/3). Applications that
 // do not support headers should return false (the default).
@@ -243,10 +239,6 @@ class Session::Application : public MemoryRetainer {
 return {StreamPriority::DEFAULT, StreamPriorityFlags::NON_INCREMENTAL};
  }
 
-// The StreamData struct is used by the application to pass pending stream
-// data to the session for transmission.
-structStreamData;
-
 virtualintGetStreamData(StreamData* data) = 0;
 virtualboolStreamCommit(StreamData* data, size_t datalen) = 0;
 
@@ -262,57 +254,9 @@ class Session::Application : public MemoryRetainer {
  }
 
 private:
- Packet::Ptr CreateStreamDataPacket();
-
-// Tries to pack a pending datagram into the current packet buffer.
-// If < 0 is returned, either NGTCP2_ERR_WRITE_MORE or a fatal error is
-// returned; the caller must check. If > 0 is returned, the packet is done
-// and the value is the size of the finalized packet. If 0 is returned,
-// the datagram is either congestion limited or was abandoned
-ssize_tTryWritePendingDatagram(PathStorage* path,
-uint8_t* dest,
-size_t destlen,
-uint64_t ts);
-
-// Write the given stream_data into the buffer. The PacketInfo out-param
-// is populated by ngtcp2 with per-packet metadata (e.g., ECN codepoint)
-// that should be applied when sending the packet.
-ssize_tWriteVStream(PathStorage* path,
- PacketInfo* pi,
-uint8_t* buf,
-ssize_t* ndatalen,
-size_t max_packet_size,
-const StreamData& stream_data,
-uint64_t ts);
-
  Session* session_ = nullptr;
 };
 
-structSession::Application::StreamData final {
-// The actual number of vectors in the struct, up to kMaxVectorCount.
-size_t count = 0;
-// The stream identifier. If this is a negative value then no stream is
-// identified.
- stream_id id = -1;
-int fin = 0;
- ngtcp2_vec data[kMaxVectorCount]{};
- BaseObjectPtr<Stream> stream;
-
-static_assert(sizeof(ngtcp2_vec) == sizeof(nghttp3_vec) &&
-alignof(ngtcp2_vec) == alignof(nghttp3_vec) &&
-offsetof(ngtcp2_vec, base) == offsetof(nghttp3_vec, base) &&
-offsetof(ngtcp2_vec, len) == offsetof(nghttp3_vec, len),
-"ngtcp2_vec and nghttp3_vec must have identical layout");
-inlineoperator nghttp3_vec*() {
-returnreinterpret_cast<nghttp3_vec*>(data);
- }
-
-inlineoperatorconst ngtcp2_vec*() const { return data; }
-inlineoperator ngtcp2_vec*() { return data; }
-
- std::string ToString() const;
-};
-
 // Create a DefaultApplication for the given session.
 std::unique_ptr<Session::Application> CreateDefaultApplication(
  Session* session, const Session::Application_Options& options);

src/quic/README.md

@@ -209,24 +209,25 @@ class Http3ApplicationImpl final : public Session::Application {
  started_ = true;
 Debug(&session(), "Starting HTTP/3 application.");
 
-auto params = ngtcp2_conn_get_remote_transport_params(session());
-if (params == nullptr) [[unlikely]] {
+constauto params = session().remote_transport_params();
+if (!params) [[unlikely]] {
 // The params are not available yet. Cannot start.
 Debug(&session(),
 "Cannot start HTTP/3 application yet. No remote transport params");
 returnfalse;
  }
 
-if (params->initial_max_streams_uni < 3) {
+if (params.initial_max_streams_uni() < 3) {
 // HTTP3 requires 3 unidirectional control streams to be opened in each
 // direction in additional to the bidirectional streams that are used to
 // actually carry request and response payload back and forth.
 // See:
 // https://nghttp2.org/nghttp3/programmers-guide.html#binding-control-streams
 Debug(&session(),
 "Cannot start HTTP/3 application. Initial max "
-"unidirectional streams [%zu] is too low. Must be at least 3",
- params->initial_max_streams_uni);
+"unidirectional streams [%" PRIu64
+"] is too low. Must be at least 3",
+ params.initial_max_streams_uni());
 returnfalse;
  }
 
@@ -235,17 +236,14 @@ class Http3ApplicationImpl final : public Session::Application {
 // of requests that the client can actually created.
 if (session().is_server()) {
 nghttp3_conn_set_max_client_streams_bidi(
- *this, params->initial_max_streams_bidi);
+ *this, params.initial_max_streams_bidi());
  }
 
 Debug(&session(), "Creating and binding HTTP/3 control streams");
 bool ret =
-ngtcp2_conn_open_uni_stream(session(), &control_stream_id_, nullptr) ==
-0 &&
-ngtcp2_conn_open_uni_stream(
-session(), &qpack_enc_stream_id_, nullptr) == 0 &&
-ngtcp2_conn_open_uni_stream(
-session(), &qpack_dec_stream_id_, nullptr) == 0 &&
+session().OpenUnidirectionalStream(&control_stream_id_) &&
+session().OpenUnidirectionalStream(&qpack_enc_stream_id_) &&
+session().OpenUnidirectionalStream(&qpack_dec_stream_id_) &&
 nghttp3_conn_bind_control_stream(*this, control_stream_id_) == 0 &&
 nghttp3_conn_bind_qpack_streams(
  *this, qpack_enc_stream_id_, qpack_dec_stream_id_) == 0;
@@ -306,8 +304,7 @@ class Http3ApplicationImpl final : public Session::Application {
 Debug(&session(),
 "Extending stream and connection offset by %zd bytes",
  nread);
-session().ExtendStreamOffset(id, nread);
-session().ExtendOffset(nread);
+session().Consume(id, nread);
  }
 
 // If this data arrived as 0-RTT, mark the stream. We set it after
@@ -365,24 +362,11 @@ class Http3ApplicationImpl final : public Session::Application {
 case EndpointLabel::LOCAL:
 return;
 case EndpointLabel::REMOTE: {
-switch (direction) {
-case Direction::BIDIRECTIONAL: {
-Debug(&session(),
-"HTTP/3 application extending max bidi streams by %" PRIu64,
- max_streams);
-ngtcp2_conn_extend_max_streams_bidi(
-session(), static_cast<size_t>(max_streams));
-break;
- }
-case Direction::UNIDIRECTIONAL: {
-Debug(&session(),
-"HTTP/3 application extending max uni streams by %" PRIu64,
- max_streams);
-ngtcp2_conn_extend_max_streams_uni(
-session(), static_cast<size_t>(max_streams));
-break;
- }
- }
+Debug(&session(),
+"HTTP/3 application extending max %s streams by %" PRIu64,
+ direction == Direction::BIDIRECTIONAL ? "bidi" : "uni",
+ max_streams);
+session().ExtendMaxStreams(direction, max_streams);
  }
  }
  }
@@ -530,8 +514,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return;
  }
 
-session().SetLastError(
-QuicError::ForApplication(nghttp3_err_infer_quic_app_error_code(rv)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(rv));
 session().Close();
  }
 
@@ -548,8 +531,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return;
  }
 
-session().SetLastError(
-QuicError::ForApplication(nghttp3_err_infer_quic_app_error_code(rv)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(rv));
 session().Close();
  }
 
@@ -687,17 +669,30 @@ class Http3ApplicationImpl final : public Session::Application {
 return {StreamPriority::DEFAULT, StreamPriorityFlags::NON_INCREMENTAL};
  }
 
-intGetStreamData(StreamData* data) override {
+intGetStreamData(Session::StreamData* data) override {
+static_assert(
+sizeof(ngtcp2_vec) == sizeof(nghttp3_vec) &&
+alignof(ngtcp2_vec) == alignof(nghttp3_vec) &&
+offsetof(ngtcp2_vec, base) == offsetof(nghttp3_vec, base) &&
+offsetof(ngtcp2_vec, len) == offsetof(nghttp3_vec, len),
+"ngtcp2_vec and nghttp3_vec must have identical layout");
  data->count = kMaxVectorCount;
 ssize_t ret = 0;
 Debug(&session(), "HTTP/3 application getting stream data");
 if (conn_ && session().max_data_left()) {
- ret = nghttp3_conn_writev_stream(
- *this, &data->id, &data->fin, *data, data->count);
+// nghttp3 reports fin through an int out-param; bridge it to the bool.
+int fin = 0;
+ ret =
+nghttp3_conn_writev_stream(*this,
+ &data->id,
+ &fin,
+reinterpret_cast<nghttp3_vec*>(data->data),
+ data->count);
 // A negative return value indicates an error.
 if (ret < 0) {
 returnstatic_cast<int>(ret);
  }
+ data->fin = fin != 0;
 
  data->count = static_cast<size_t>(ret);
 if (data->id >= 0 && data->id != control_stream_id_ &&
@@ -710,7 +705,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return0;
  }
 
-boolStreamCommit(StreamData* data, size_t datalen) override {
+boolStreamCommit(Session::StreamData* data, size_t datalen) override {
 Debug(&session(),
 "HTTP/3 application committing stream %" PRIi64 " data %zu",
  data->id,
@@ -720,8 +715,7 @@ class Http3ApplicationImpl final : public Session::Application {
 // nghttp3 tracks its own offset via add_write_offset.
 int err = nghttp3_conn_add_write_offset(*this, data->id, datalen);
 if (err != 0) {
-session().SetLastError(QuicError::ForApplication(
-nghttp3_err_infer_quic_app_error_code(err)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(err));
 returnfalse;
  }
 // Raw application bytes are committed to the stream's outbound
@@ -1212,10 +1206,10 @@ class Http3ApplicationImpl final : public Session::Application {
 void* conn_user_data,
 void* stream_user_data) {
 NGHTTP3_CALLBACK_SCOPE(app);
-auto& session = app.session();
-Debug(&session, "HTTP/3 application deferred consume %zu bytes", consumed);
-session.ExtendStreamOffset(id, consumed);
- session.ExtendOffset(consumed);
+Debug(&app.session(),
+"HTTP/3 application deferred consume %zu bytes",
+ consumed);
+app.session().Consume(id, consumed);
 returnNGTCP2_SUCCESS;
  }
 

src/quic/application.cc

@@ -77,7 +77,7 @@ data channels that carry application data.
 
 Every entry point that may generate outbound data creates a
 `SendPendingDataScope`. Scopes nest — an internal depth counter ensures
-`Application::SendPendingData()` is called exactly once, when the outermost
+`Session::SendPendingData()` is called exactly once, when the outermost
 scope exits:
 
 ```cpp
@@ -218,13 +218,13 @@ Session::Receive()
 
 ```text
 SendPendingDataScope::~SendPendingDataScope()
- → Application::SendPendingData()
+ → Session::SendPendingData()
  Loop (up to max_packet_count):
- ├── GetStreamData() // pull data from next stream
- │ └── stream->Pull() // bob pull from Outbound→DataQueue
- ├── WriteVStream() // ngtcp2_conn_writev_stream()
+ ├── application().GetStreamData() // pull data from next stream
+ │ └── stream->Pull() // bob pull from Outbound→DataQueue
+ ├── WriteVStream() // ngtcp2_conn_writev_stream()
  │ encrypts, frames, paces
- ├── if ndatalen > 0: StreamCommit()
+ ├── if ndatalen > 0: application().StreamCommit()
  │ stream->Commit(datalen, fin)
  ├── if nwrite > 0: Send() // uv_udp_send()
  ├── if WRITE_MORE: continue // room for more in this packet

src/quic/application.h

@@ -205,10 +205,6 @@ class Session::Application : public MemoryRetainer {
 returnfalse;
  }
 
-// Signals to the Application that it should serialize and transmit any
-// pending session and stream packets it has accumulated.
-voidSendPendingData();
-
 // Returns true if the application protocol supports sending and
 // receiving headers on streams (e.g. HTTP/3). Applications that
 // do not support headers should return false (the default).
@@ -243,10 +239,6 @@ class Session::Application : public MemoryRetainer {
 return {StreamPriority::DEFAULT, StreamPriorityFlags::NON_INCREMENTAL};
  }
 
-// The StreamData struct is used by the application to pass pending stream
-// data to the session for transmission.
-structStreamData;
-
 virtualintGetStreamData(StreamData* data) = 0;
 virtualboolStreamCommit(StreamData* data, size_t datalen) = 0;
 
@@ -262,57 +254,9 @@ class Session::Application : public MemoryRetainer {
  }
 
 private:
- Packet::Ptr CreateStreamDataPacket();
-
-// Tries to pack a pending datagram into the current packet buffer.
-// If < 0 is returned, either NGTCP2_ERR_WRITE_MORE or a fatal error is
-// returned; the caller must check. If > 0 is returned, the packet is done
-// and the value is the size of the finalized packet. If 0 is returned,
-// the datagram is either congestion limited or was abandoned
-ssize_tTryWritePendingDatagram(PathStorage* path,
-uint8_t* dest,
-size_t destlen,
-uint64_t ts);
-
-// Write the given stream_data into the buffer. The PacketInfo out-param
-// is populated by ngtcp2 with per-packet metadata (e.g., ECN codepoint)
-// that should be applied when sending the packet.
-ssize_tWriteVStream(PathStorage* path,
- PacketInfo* pi,
-uint8_t* buf,
-ssize_t* ndatalen,
-size_t max_packet_size,
-const StreamData& stream_data,
-uint64_t ts);
-
  Session* session_ = nullptr;
 };
 
-structSession::Application::StreamData final {
-// The actual number of vectors in the struct, up to kMaxVectorCount.
-size_t count = 0;
-// The stream identifier. If this is a negative value then no stream is
-// identified.
- stream_id id = -1;
-int fin = 0;
- ngtcp2_vec data[kMaxVectorCount]{};
- BaseObjectPtr<Stream> stream;
-
-static_assert(sizeof(ngtcp2_vec) == sizeof(nghttp3_vec) &&
-alignof(ngtcp2_vec) == alignof(nghttp3_vec) &&
-offsetof(ngtcp2_vec, base) == offsetof(nghttp3_vec, base) &&
-offsetof(ngtcp2_vec, len) == offsetof(nghttp3_vec, len),
-"ngtcp2_vec and nghttp3_vec must have identical layout");
-inlineoperator nghttp3_vec*() {
-returnreinterpret_cast<nghttp3_vec*>(data);
- }
-
-inlineoperatorconst ngtcp2_vec*() const { return data; }
-inlineoperator ngtcp2_vec*() { return data; }
-
- std::string ToString() const;
-};
-
 // Create a DefaultApplication for the given session.
 std::unique_ptr<Session::Application> CreateDefaultApplication(
  Session* session, const Session::Application_Options& options);

src/quic/http3.cc

@@ -209,24 +209,25 @@ class Http3ApplicationImpl final : public Session::Application {
  started_ = true;
 Debug(&session(), "Starting HTTP/3 application.");
 
-auto params = ngtcp2_conn_get_remote_transport_params(session());
-if (params == nullptr) [[unlikely]] {
+constauto params = session().remote_transport_params();
+if (!params) [[unlikely]] {
 // The params are not available yet. Cannot start.
 Debug(&session(),
 "Cannot start HTTP/3 application yet. No remote transport params");
 returnfalse;
  }
 
-if (params->initial_max_streams_uni < 3) {
+if (params.initial_max_streams_uni() < 3) {
 // HTTP3 requires 3 unidirectional control streams to be opened in each
 // direction in additional to the bidirectional streams that are used to
 // actually carry request and response payload back and forth.
 // See:
 // https://nghttp2.org/nghttp3/programmers-guide.html#binding-control-streams
 Debug(&session(),
 "Cannot start HTTP/3 application. Initial max "
-"unidirectional streams [%zu] is too low. Must be at least 3",
- params->initial_max_streams_uni);
+"unidirectional streams [%" PRIu64
+"] is too low. Must be at least 3",
+ params.initial_max_streams_uni());
 returnfalse;
  }
 
@@ -235,17 +236,14 @@ class Http3ApplicationImpl final : public Session::Application {
 // of requests that the client can actually created.
 if (session().is_server()) {
 nghttp3_conn_set_max_client_streams_bidi(
- *this, params->initial_max_streams_bidi);
+ *this, params.initial_max_streams_bidi());
  }
 
 Debug(&session(), "Creating and binding HTTP/3 control streams");
 bool ret =
-ngtcp2_conn_open_uni_stream(session(), &control_stream_id_, nullptr) ==
-0 &&
-ngtcp2_conn_open_uni_stream(
-session(), &qpack_enc_stream_id_, nullptr) == 0 &&
-ngtcp2_conn_open_uni_stream(
-session(), &qpack_dec_stream_id_, nullptr) == 0 &&
+session().OpenUnidirectionalStream(&control_stream_id_) &&
+session().OpenUnidirectionalStream(&qpack_enc_stream_id_) &&
+session().OpenUnidirectionalStream(&qpack_dec_stream_id_) &&
 nghttp3_conn_bind_control_stream(*this, control_stream_id_) == 0 &&
 nghttp3_conn_bind_qpack_streams(
  *this, qpack_enc_stream_id_, qpack_dec_stream_id_) == 0;
@@ -306,8 +304,7 @@ class Http3ApplicationImpl final : public Session::Application {
 Debug(&session(),
 "Extending stream and connection offset by %zd bytes",
  nread);
-session().ExtendStreamOffset(id, nread);
-session().ExtendOffset(nread);
+session().Consume(id, nread);
  }
 
 // If this data arrived as 0-RTT, mark the stream. We set it after
@@ -365,24 +362,11 @@ class Http3ApplicationImpl final : public Session::Application {
 case EndpointLabel::LOCAL:
 return;
 case EndpointLabel::REMOTE: {
-switch (direction) {
-case Direction::BIDIRECTIONAL: {
-Debug(&session(),
-"HTTP/3 application extending max bidi streams by %" PRIu64,
- max_streams);
-ngtcp2_conn_extend_max_streams_bidi(
-session(), static_cast<size_t>(max_streams));
-break;
- }
-case Direction::UNIDIRECTIONAL: {
-Debug(&session(),
-"HTTP/3 application extending max uni streams by %" PRIu64,
- max_streams);
-ngtcp2_conn_extend_max_streams_uni(
-session(), static_cast<size_t>(max_streams));
-break;
- }
- }
+Debug(&session(),
+"HTTP/3 application extending max %s streams by %" PRIu64,
+ direction == Direction::BIDIRECTIONAL ? "bidi" : "uni",
+ max_streams);
+session().ExtendMaxStreams(direction, max_streams);
  }
  }
  }
@@ -530,8 +514,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return;
  }
 
-session().SetLastError(
-QuicError::ForApplication(nghttp3_err_infer_quic_app_error_code(rv)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(rv));
 session().Close();
  }
 
@@ -548,8 +531,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return;
  }
 
-session().SetLastError(
-QuicError::ForApplication(nghttp3_err_infer_quic_app_error_code(rv)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(rv));
 session().Close();
  }
 
@@ -687,17 +669,30 @@ class Http3ApplicationImpl final : public Session::Application {
 return {StreamPriority::DEFAULT, StreamPriorityFlags::NON_INCREMENTAL};
  }
 
-intGetStreamData(StreamData* data) override {
+intGetStreamData(Session::StreamData* data) override {
+static_assert(
+sizeof(ngtcp2_vec) == sizeof(nghttp3_vec) &&
+alignof(ngtcp2_vec) == alignof(nghttp3_vec) &&
+offsetof(ngtcp2_vec, base) == offsetof(nghttp3_vec, base) &&
+offsetof(ngtcp2_vec, len) == offsetof(nghttp3_vec, len),
+"ngtcp2_vec and nghttp3_vec must have identical layout");
  data->count = kMaxVectorCount;
 ssize_t ret = 0;
 Debug(&session(), "HTTP/3 application getting stream data");
 if (conn_ && session().max_data_left()) {
- ret = nghttp3_conn_writev_stream(
- *this, &data->id, &data->fin, *data, data->count);
+// nghttp3 reports fin through an int out-param; bridge it to the bool.
+int fin = 0;
+ ret =
+nghttp3_conn_writev_stream(*this,
+ &data->id,
+ &fin,
+reinterpret_cast<nghttp3_vec*>(data->data),
+ data->count);
 // A negative return value indicates an error.
 if (ret < 0) {
 returnstatic_cast<int>(ret);
  }
+ data->fin = fin != 0;
 
  data->count = static_cast<size_t>(ret);
 if (data->id >= 0 && data->id != control_stream_id_ &&
@@ -710,7 +705,7 @@ class Http3ApplicationImpl final : public Session::Application {
 return0;
  }
 
-boolStreamCommit(StreamData* data, size_t datalen) override {
+boolStreamCommit(Session::StreamData* data, size_t datalen) override {
 Debug(&session(),
 "HTTP/3 application committing stream %" PRIi64 " data %zu",
  data->id,
@@ -720,8 +715,7 @@ class Http3ApplicationImpl final : public Session::Application {
 // nghttp3 tracks its own offset via add_write_offset.
 int err = nghttp3_conn_add_write_offset(*this, data->id, datalen);
 if (err != 0) {
-session().SetLastError(QuicError::ForApplication(
-nghttp3_err_infer_quic_app_error_code(err)));
+session().SetApplicationError(nghttp3_err_infer_quic_app_error_code(err));
 returnfalse;
  }
 // Raw application bytes are committed to the stream's outbound
@@ -1212,10 +1206,10 @@ class Http3ApplicationImpl final : public Session::Application {
 void* conn_user_data,
 void* stream_user_data) {
 NGHTTP3_CALLBACK_SCOPE(app);
-auto& session = app.session();
-Debug(&session, "HTTP/3 application deferred consume %zu bytes", consumed);
-session.ExtendStreamOffset(id, consumed);
- session.ExtendOffset(consumed);
+Debug(&app.session(),
+"HTTP/3 application deferred consume %zu bytes",
+ consumed);
+app.session().Consume(id, consumed);
 returnNGTCP2_SUCCESS;
  }