[PH2][Transport] Grpc Header Read and Write (grpc#38984)

[PH2][Transport]

1. Grpc Header Read and Write
2. Adding some build dependencies that we need for the next Pull Request. Adding this in the other workflow will cause multiple build issues because of copybara.

Closes grpc#38984

COPYBARA_INTEGRATE_REVIEW=grpc#38984 from tanvi-jagtap:ph2_trivial_build 0ad2529
PiperOrigin-RevId: 737890700

Author: tanvi-jagtap

CMakeLists.txt

@@ -7532,6 +7532,8 @@ grpc_cc_library(
         "http2_transport",
         "loop",
         "map",
+        "message",
+        "metadata",
         "mpsc",
         "sync",
         ":match_promise",
@@ -7576,6 +7578,8 @@ grpc_cc_library(
         "http2_settings",
         "loop",
         "map",
+        "message",
+        "metadata",
         "mpsc",
         "ref_counted",
         "sync",

Makefile

@@ -23,6 +23,7 @@
 #include "absl/log/check.h"
 #include "absl/status/status.h"
 #include "absl/strings/str_cat.h"
+#include "src/core/lib/slice/slice_buffer.h"
 #include "src/core/util/crash.h"
 
 namespace grpc_core {
@@ -525,4 +526,21 @@ absl::StatusOr<Http2Frame> ParseFramePayload(const Http2FrameHeader& hdr,
   }
 }
 
+GrpcMessageHeader ExtractGrpcHeader(SliceBuffer& payload) {
+  CHECK_GE(payload.Length(), kGrpcHeaderSizeInBytes);
+  uint8_t buffer[kGrpcHeaderSizeInBytes];
+  payload.MoveFirstNBytesIntoBuffer(kGrpcHeaderSizeInBytes, buffer);
+  GrpcMessageHeader header;
+  header.flags = buffer[0];
+  header.length = Read4b(buffer + 1);
+  return header;
+}
+
+void AppendGrpcHeaderToSliceBuffer(SliceBuffer& payload, const uint8_t flags,
+                                   const uint32_t length) {
+  uint8_t* frame_hdr = payload.AddTiny(kGrpcHeaderSizeInBytes);
+  frame_hdr[0] = flags;
+  Write4b(length, frame_hdr + 1);
+}
+
 }  // namespace grpc_core

Package.swift

@@ -236,6 +236,24 @@ absl::StatusOr<Http2Frame> ParseFramePayload(const Http2FrameHeader& hdr,
 // move things out of frames)
 void Serialize(absl::Span<Http2Frame> frames, SliceBuffer& out);
 
+///////////////////////////////////////////////////////////////////////////////
+// GRPC Header
+
+constexpr uint8_t kGrpcHeaderSizeInBytes = 5;
+
+struct GrpcMessageHeader {
+  uint8_t flags;
+  uint32_t length;
+};
+
+// If the payload SliceBuffer is too small to hold a gRPC header, this function
+// will crash. The calling function MUST ensure that the payload SliceBuffer
+// has length greater than or equal to the gRPC header.
+GrpcMessageHeader ExtractGrpcHeader(SliceBuffer& payload);
+
+void AppendGrpcHeaderToSliceBuffer(SliceBuffer& payload, const uint8_t flags,
+                                   const uint32_t length);
+
 }  // namespace grpc_core
 
 #endif  // GRPC_SRC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_FRAME_H

build_autogenerated.yaml

@@ -182,6 +182,7 @@ grpc_cc_test(
     deps = [
         "//:chttp2_frame",
         "//src/core:http2_errors",
+        "//src/core:slice_buffer",
     ],
 )
 
@@ -515,6 +516,8 @@ grpc_cc_test(
         "//:gpr",
         "//:grpc",
         "//src/core:http2_client_transport",
+        "//src/core:message",
+        "//src/core:metadata",
         "//test/core/promise:poll_matcher",
         "//test/core/test_util:grpc_test_util",
         "//test/core/test_util:grpc_test_util_base",
@@ -538,6 +541,8 @@ grpc_cc_test(
         "//:gpr",
         "//:grpc",
         "//src/core:http2_server_transport",
+        "//src/core:message",
+        "//src/core:metadata",
         "//test/core/test_util:grpc_test_util",
         "//test/core/test_util:grpc_test_util_base",
         "//test/core/transport/chttp2:http2_frame_test_helper",

config.m4

@@ -21,6 +21,7 @@
 #include "absl/status/status.h"
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
+#include "src/core/lib/slice/slice_buffer.h"
 #include "src/core/lib/transport/http2_errors.h"
 
 namespace grpc_core {
@@ -404,6 +405,22 @@ TEST(Frame, ParseRejects) {
                        "stream_id=0, length=4}"));
 }
 
+TEST(Frame, GrpcHeaderTest) {
+  constexpr uint8_t kFlags = 15;
+  constexpr uint32_t kLength = 1111111;
+
+  SliceBuffer payload;
+  EXPECT_EQ(payload.Length(), 0);
+
+  AppendGrpcHeaderToSliceBuffer(payload, kFlags, kLength);
+  EXPECT_EQ(payload.Length(), kGrpcHeaderSizeInBytes);
+
+  GrpcMessageHeader header = ExtractGrpcHeader(payload);
+  EXPECT_EQ(payload.Length(), 0);
+  EXPECT_EQ(header.flags, kFlags);
+  EXPECT_EQ(header.length, kLength);
+}
+
 }  // namespace
 }  // namespace grpc_core