text: /*
   *
   * Copyright 2015 gRPC authors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   *
   */
  
  #include <grpc/support/port_platform.h>
  
  #include "src/core/ext/transport/chttp2/transport/frame_rst_stream.h"
  
  #include "absl/strings/str_cat.h"
  #include "absl/strings/str_format.h"
  
  #include <grpc/support/alloc.h>
  #include <grpc/support/log.h>
  
  #include "src/core/ext/transport/chttp2/transport/frame.h"
  #include "src/core/ext/transport/chttp2/transport/internal.h"
  #include "src/core/lib/gprpp/memory.h"
  #include "src/core/lib/transport/http2_errors.h"
  
  grpc_slice grpc_chttp2_rst_stream_create(uint32_t id, uint32_t code,
                                           grpc_transport_one_way_stats* stats) {
    static const size_t frame_size = 13;
    grpc_slice slice = GRPC_SLICE_MALLOC(frame_size);
    if (stats != nullptr) stats->framing_bytes += frame_size;
    uint8_t* p = GRPC_SLICE_START_PTR(slice);
  
    // Frame size.
    *p++ = 0;
    *p++ = 0;
    *p++ = 4;
    // Frame type.
    *p++ = GRPC_CHTTP2_FRAME_RST_STREAM;
    // Flags.
    *p++ = 0;
    // Stream ID.
    *p++ = static_cast<uint8_t>(id >> 24);
    *p++ = static_cast<uint8_t>(id >> 16);
    *p++ = static_cast<uint8_t>(id >> 8);
    *p++ = static_cast<uint8_t>(id);
    // Error code.
    *p++ = static_cast<uint8_t>(code >> 24);
    *p++ = static_cast<uint8_t>(code >> 16);
    *p++ = static_cast<uint8_t>(code >> 8);
    *p++ = static_cast<uint8_t>(code);
  
    return slice;
  }
  
  void grpc_chttp2_add_rst_stream_to_next_write(
      grpc_chttp2_transport* t, uint32_t id, uint32_t code,
      grpc_transport_one_way_stats* stats) {
    t->num_pending_induced_frames++;
    grpc_slice_buffer_add(&t->qbuf,
                          grpc_chttp2_rst_stream_create(id, code, stats));
  }
  
  grpc_error_handle grpc_chttp2_rst_stream_parser_begin_frame(
      grpc_chttp2_rst_stream_parser* parser, uint32_t length, uint8_t flags) {
    if (length != 4) {
      return GRPC_ERROR_CREATE_FROM_CPP_STRING(absl::StrFormat(
          "invalid rst_stream: length=%d, flags=%02x", length, flags));
    }
    parser->byte = 0;
    return GRPC_ERROR_NONE;
  }
  
  grpc_error_handle grpc_chttp2_rst_stream_parser_parse(void* parser,
                                                        grpc_chttp2_transport* t,
                                                        grpc_chttp2_stream* s,
                                                        const grpc_slice& slice,
                                                        int is_last) {
    const uint8_t* const beg = GRPC_SLICE_START_PTR(slice);
    const uint8_t* const end = GRPC_SLICE_END_PTR(slice);
    const uint8_t* cur = beg;
    grpc_chttp2_rst_stream_parser* p =
        static_cast<grpc_chttp2_rst_stream_parser*>(parser);
  
    while (p->byte != 4 && cur != end) {
      p->reason_bytes[p->byte] = *cur;
      cur++;
      p->byte++;
    }
    s->stats.incoming.framing_bytes += static_cast<uint64_t>(end - cur);
  
    if (p->byte == 4) {
      GPR_ASSERT(is_last);
      uint32_t reason = ((static_cast<uint32_t>(p->reason_bytes[0])) << 24) |
                        ((static_cast<uint32_t>(p->reason_bytes[1])) << 16) |
                        ((static_cast<uint32_t>(p->reason_bytes[2])) << 8) |
                        ((static_cast<uint32_t>(p->reason_bytes[3])));
      if (GRPC_TRACE_FLAG_ENABLED(grpc_http_trace)) {
        gpr_log(GPR_INFO,
                "[chttp2 transport=%p stream=%p] received RST_STREAM(reason=%d)",
                t, s, reason);
      }
      grpc_error_handle error = GRPC_ERROR_NONE;
      if (reason != GRPC_HTTP2_NO_ERROR || s->trailing_metadata_buffer.empty()) {
        error = grpc_error_set_int(
            grpc_error_set_str(
                GRPC_ERROR_CREATE_FROM_STATIC_STRING("RST_STREAM"),
                GRPC_ERROR_STR_GRPC_MESSAGE,
                absl::StrCat("Received RST_STREAM with error code ", reason)),
            GRPC_ERROR_INT_HTTP2_ERROR, static_cast<intptr_t>(reason));
      }
      grpc_chttp2_mark_stream_closed(t, s, true, true, error);
    }
  
    return GRPC_ERROR_NONE;
  }
  