[chaotic-good] Fix frame serialization (#34711)

This PR aims to fix the issue found in frame_fuzzer after #34191 was
merged, where frame serialization is missing the frame header info and
causes mismatch with the original frame.

This PR needs to be merged before #34657.

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src/core/BUILD

@@ -6183,7 +6183,6 @@ grpc_cc_library(
     external_deps = [
         "absl/base:core_headers",
         "absl/status",
-        "absl/status:statusor",
         "absl/types:variant",
     ],
     language = "c++",

src/core/ext/transport/chaotic_good/client_transport.cc

@@ -20,10 +20,7 @@
 #include <string>
 #include <tuple>
 
-#include "absl/status/statusor.h"
-
 #include <grpc/event_engine/event_engine.h>
-#include <grpc/slice.h>
 #include <grpc/support/log.h>
 
 #include "src/core/ext/transport/chaotic_good/frame.h"
@@ -65,16 +62,10 @@ ClientTransport::ClientTransport(
                 control_endpoint_write_buffer_.Append(
                     frame->Serialize(hpack_compressor_.get()));
                 if (frame->message != nullptr) {
-                  auto frame_header =
-                      FrameHeader::Parse(
-                          reinterpret_cast<const uint8_t*>(GRPC_SLICE_START_PTR(
-                              control_endpoint_write_buffer_.c_slice_buffer()
-                                  ->slices[0])))
-                          .value();
-                  std::string message_padding(frame_header.message_padding,
-                                              '0');
+                  std::string message_padding(
+                      frame->frame_header.message_padding, '0');
                   Slice slice(grpc_slice_from_cpp_string(message_padding));
-                  // Append message payload to data_endpoint_buffer.
+                  // Append message padding to data_endpoint_buffer.
                   data_endpoint_write_buffer_.Append(std::move(slice));
                   // Append message payload to data_endpoint_buffer.
                   frame->message->payload()->MoveFirstNBytesIntoSliceBuffer(

src/core/ext/transport/chaotic_good/client_transport.h

@@ -17,6 +17,7 @@
 
 #include <grpc/support/port_platform.h>
 
+#include <stddef.h>
 #include <stdint.h>
 
 #include <initializer_list>  // IWYU pragma: keep
@@ -31,6 +32,7 @@
 #include <grpc/event_engine/event_engine.h>
 
 #include "src/core/ext/transport/chaotic_good/frame.h"
+#include "src/core/ext/transport/chaotic_good/frame_header.h"
 #include "src/core/ext/transport/chttp2/transport/hpack_encoder.h"
 #include "src/core/lib/gprpp/sync.h"
 #include "src/core/lib/promise/activity.h"
@@ -60,7 +62,7 @@ class ClientTransport {
   auto AddStream(CallArgs call_args) {
     // At this point, the connection is set up.
     // Start sending data frames.
-    uint64_t stream_id;
+    uint32_t stream_id;
     {
       MutexLock lock(&mu_);
       stream_id = next_stream_id_++;
@@ -71,10 +73,16 @@ class ClientTransport {
                 [stream_id, initial_frame = true,
                  client_initial_metadata =
                      std::move(call_args.client_initial_metadata),
-                 outgoing_frames = outgoing_frames_.MakeSender()](
-                    MessageHandle result) mutable {
+                 outgoing_frames = outgoing_frames_.MakeSender(),
+                 this](MessageHandle result) mutable {
                   ClientFragmentFrame frame;
-                  frame.stream_id = stream_id;
+                  // Construct frame header (flags, header_length and
+                  // trailer_length will be added in serialization).
+                  uint32_t message_length = result->payload()->Length();
+                  uint32_t message_padding = message_length % aligned_bytes;
+                  frame.frame_header = FrameHeader{
+                      FrameType::kFragment, {}, stream_id, 0, message_length,
+                      message_padding,      0};
                   frame.message = std::move(result);
                   if (initial_frame) {
                     // Send initial frame with client intial metadata.
@@ -99,6 +107,8 @@ class ClientTransport {
   MpscReceiver<ClientFrame> outgoing_frames_;
   Mutex mu_;
   uint32_t next_stream_id_ ABSL_GUARDED_BY(mu_) = 1;
+  // Assigned aligned bytes from setting frame.
+  size_t aligned_bytes = 64;
   ActivityPtr writer_;
   ActivityPtr reader_;
   std::unique_ptr<PromiseEndpoint> control_endpoint_;

src/core/ext/transport/chaotic_good/frame.cc

@@ -28,6 +28,7 @@
 #include <grpc/slice.h>
 #include <grpc/support/log.h>
 
+#include "src/core/ext/transport/chaotic_good/frame_header.h"
 #include "src/core/lib/gprpp/bitset.h"
 #include "src/core/lib/gprpp/no_destruct.h"
 #include "src/core/lib/gprpp/status_helper.h"
@@ -40,15 +41,14 @@ namespace chaotic_good {
 namespace {
 const NoDestruct<Slice> kZeroSlice{[] {
   // Frame header size is fixed to 24 bytes.
-  auto slice = GRPC_SLICE_MALLOC(24);
-  memset(GRPC_SLICE_START_PTR(slice), 0, 24);
+  auto slice = GRPC_SLICE_MALLOC(FrameHeader::frame_header_size_);
+  memset(GRPC_SLICE_START_PTR(slice), 0, FrameHeader::frame_header_size_);
   return slice;
 }()};
 
 class FrameSerializer {
  public:
-  explicit FrameSerializer(FrameType type, uint32_t stream_id)
-      : header_{type, {}, stream_id, 0, 0, 0, 0} {
+  explicit FrameSerializer(FrameHeader header) : header_(header) {
     output_.AppendIndexed(kZeroSlice->Copy());
   }
   // If called, must be called before AddTrailers, Finish.
@@ -59,10 +59,24 @@ class FrameSerializer {
   // If called, must be called before Finish.
   SliceBuffer& AddTrailers() {
     header_.flags.set(1);
+    header_.header_length = output_.Length() - FrameHeader::frame_header_size_;
     return output_;
   }
 
   SliceBuffer Finish() {
+    // Calculate frame header_length or trailer_length if available.
+    if (header_.flags.is_set(1)) {
+      // Header length is already known in AddTrailers().
+      header_.trailer_length = output_.Length() - header_.header_length -
+                               FrameHeader::frame_header_size_;
+    } else {
+      if (header_.flags.is_set(0)) {
+        // Calculate frame header length in Finish() since AddTrailers() isn't
+        // called.
+        header_.header_length =
+            output_.Length() - FrameHeader::frame_header_size_;
+      }
+    }
     header_.Serialize(
         GRPC_SLICE_START_PTR(output_.c_slice_buffer()->slices[0]));
     return std::move(output_);
@@ -151,7 +165,8 @@ absl::Status SettingsFrame::Deserialize(HPackParser*, const FrameHeader& header,
 }
 
 SliceBuffer SettingsFrame::Serialize(HPackCompressor*) const {
-  FrameSerializer serializer(FrameType::kSettings, 0);
+  FrameSerializer serializer(
+      FrameHeader{FrameType::kSettings, {}, 0, 0, 0, 0, 0});
   return serializer.Finish();
 }
 
@@ -162,7 +177,7 @@ absl::Status ClientFragmentFrame::Deserialize(HPackParser* parser,
   if (header.stream_id == 0) {
     return absl::InvalidArgumentError("Expected non-zero stream id");
   }
-  stream_id = header.stream_id;
+  frame_header = header;
   if (header.type != FrameType::kFragment) {
     return absl::InvalidArgumentError("Expected fragment frame");
   }
@@ -171,6 +186,9 @@ absl::Status ClientFragmentFrame::Deserialize(HPackParser* parser,
     auto r = ReadMetadata<ClientMetadata>(parser, deserializer.ReceiveHeaders(),
                                           header.stream_id, true, true, bitsrc);
     if (!r.ok()) return r.status();
+    if (r.value() != nullptr) {
+      headers = std::move(r.value());
+    }
   }
   if (header.flags.is_set(1)) {
     if (header.trailer_length != 0) {
@@ -184,8 +202,8 @@ absl::Status ClientFragmentFrame::Deserialize(HPackParser* parser,
 }
 
 SliceBuffer ClientFragmentFrame::Serialize(HPackCompressor* encoder) const {
-  GPR_ASSERT(stream_id != 0);
-  FrameSerializer serializer(FrameType::kFragment, stream_id);
+  GPR_ASSERT(frame_header.stream_id != 0);
+  FrameSerializer serializer(frame_header);
   if (headers.get() != nullptr) {
     encoder->EncodeRawHeaders(*headers.get(), serializer.AddHeaders());
   }
@@ -202,28 +220,32 @@ absl::Status ServerFragmentFrame::Deserialize(HPackParser* parser,
   if (header.stream_id == 0) {
     return absl::InvalidArgumentError("Expected non-zero stream id");
   }
-  stream_id = header.stream_id;
-  if (header.type != FrameType::kFragment) {
-    return absl::InvalidArgumentError("Expected fragment frame");
-  }
+  frame_header = header;
   FrameDeserializer deserializer(header, slice_buffer);
   if (header.flags.is_set(0)) {
     auto r =
         ReadMetadata<ServerMetadata>(parser, deserializer.ReceiveHeaders(),
                                      header.stream_id, true, false, bitsrc);
     if (!r.ok()) return r.status();
+    if (r.value() != nullptr) {
+      headers = std::move(r.value());
+    }
   }
   if (header.flags.is_set(1)) {
     auto r =
         ReadMetadata<ServerMetadata>(parser, deserializer.ReceiveTrailers(),
                                      header.stream_id, false, false, bitsrc);
+    if (!r.ok()) return r.status();
+    if (r.value() != nullptr) {
+      trailers = std::move(r.value());
+    }
   }
   return deserializer.Finish();
 }
 
 SliceBuffer ServerFragmentFrame::Serialize(HPackCompressor* encoder) const {
-  GPR_ASSERT(stream_id != 0);
-  FrameSerializer serializer(FrameType::kFragment, stream_id);
+  GPR_ASSERT(frame_header.stream_id != 0);
+  FrameSerializer serializer(frame_header);
   if (headers.get() != nullptr) {
     encoder->EncodeRawHeaders(*headers.get(), serializer.AddHeaders());
   }
@@ -252,7 +274,8 @@ absl::Status CancelFrame::Deserialize(HPackParser*, const FrameHeader& header,
 
 SliceBuffer CancelFrame::Serialize(HPackCompressor*) const {
   GPR_ASSERT(stream_id != 0);
-  FrameSerializer serializer(FrameType::kCancel, stream_id);
+  FrameSerializer serializer(
+      FrameHeader{FrameType::kCancel, {}, stream_id, 0, 0, 0, 0});
   return serializer.Finish();
 }
 

src/core/ext/transport/chaotic_good/frame.h

@@ -77,13 +77,14 @@ struct ClientFragmentFrame final : public FrameInterface {
                            SliceBuffer& slice_buffer) override;
   SliceBuffer Serialize(HPackCompressor* encoder) const override;
 
-  uint32_t stream_id;
+  FrameHeader frame_header;
   ClientMetadataHandle headers;
   MessageHandle message;
   bool end_of_stream = false;
 
   bool operator==(const ClientFragmentFrame& other) const {
-    return stream_id == other.stream_id && EqHdl(headers, other.headers) &&
+    return frame_header.stream_id == other.frame_header.stream_id &&
+           EqHdl(headers, other.headers) &&
            end_of_stream == other.end_of_stream;
   }
 };
@@ -94,13 +95,13 @@ struct ServerFragmentFrame final : public FrameInterface {
                            SliceBuffer& slice_buffer) override;
   SliceBuffer Serialize(HPackCompressor* encoder) const override;
 
-  uint32_t stream_id;
+  FrameHeader frame_header;
   ServerMetadataHandle headers;
   ServerMetadataHandle trailers;
 
   bool operator==(const ServerFragmentFrame& other) const {
-    return stream_id == other.stream_id && EqHdl(headers, other.headers) &&
-           EqHdl(trailers, other.trailers);
+    return frame_header.stream_id == other.frame_header.stream_id &&
+           EqHdl(headers, other.headers) && EqHdl(trailers, other.trailers);
   }
 };
 

src/core/ext/transport/chaotic_good/frame_header.h

@@ -17,6 +17,8 @@
 
 #include <grpc/support/port_platform.h>
 
+#include <stddef.h>
+
 #include <cstdint>
 
 #include "absl/status/statusor.h"
@@ -55,6 +57,8 @@ struct FrameHeader {
            message_padding == h.message_padding &&
            trailer_length == h.trailer_length;
   }
+  // Frame header size is fixed to 24 bytes.
+  static constexpr size_t frame_header_size_ = 24;
 };
 
 }  // namespace chaotic_good

test/core/transport/chaotic_good/client_transport_test.cc

@@ -16,8 +16,6 @@
 
 // IWYU pragma: no_include <sys/socket.h>
 
-#include <stdio.h>
-
 #include <algorithm>  // IWYU pragma: keep
 #include <memory>
 #include <tuple>