1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef QUICHE_SPDY_CORE_SPDY_FRAME_BUILDER_H_ 6 #define QUICHE_SPDY_CORE_SPDY_FRAME_BUILDER_H_ 7 8 #include <cstddef> 9 #include <cstdint> 10 #include <memory> 11 12 #include "absl/strings/string_view.h" 13 #include "quiche/common/platform/api/quiche_bug_tracker.h" 14 #include "quiche/common/platform/api/quiche_export.h" 15 #include "quiche/common/quiche_endian.h" 16 #include "quiche/spdy/core/spdy_protocol.h" 17 #include "quiche/spdy/core/zero_copy_output_buffer.h" 18 19 namespace spdy { 20 21 namespace test { 22 class SpdyFrameBuilderPeer; 23 } // namespace test 24 25 // This class provides facilities for basic binary value packing 26 // into Spdy frames. 27 // 28 // The SpdyFrameBuilder supports appending primitive values (int, string, etc) 29 // to a frame instance. The SpdyFrameBuilder grows its internal memory buffer 30 // dynamically to hold the sequence of primitive values. The internal memory 31 // buffer is exposed as the "data" of the SpdyFrameBuilder. 32 class QUICHE_EXPORT SpdyFrameBuilder { 33 public: 34 // Initializes a SpdyFrameBuilder with a buffer of given size 35 explicit SpdyFrameBuilder(size_t size); 36 // Doesn't take ownership of output. 37 SpdyFrameBuilder(size_t size, ZeroCopyOutputBuffer* output); 38 39 ~SpdyFrameBuilder(); 40 41 // Returns the total size of the SpdyFrameBuilder's data, which may include 42 // multiple frames. length()43 size_t length() const { return offset_ + length_; } 44 45 // Seeks forward by the given number of bytes. Useful in conjunction with 46 // GetWriteableBuffer() above. 47 bool Seek(size_t length); 48 49 // Populates this frame with a HTTP2 frame prefix using length information 50 // from |capacity_|. The given type must be a control frame type. 51 bool BeginNewFrame(SpdyFrameType type, uint8_t flags, SpdyStreamId stream_id); 52 53 // Populates this frame with a HTTP2 frame prefix with type and length 54 // information. |type| must be a defined frame type. 55 bool BeginNewFrame(SpdyFrameType type, uint8_t flags, SpdyStreamId stream_id, 56 size_t length); 57 58 // Populates this frame with a HTTP2 frame prefix with type and length 59 // information. |raw_frame_type| may be a defined or undefined frame type. 60 bool BeginNewUncheckedFrame(uint8_t raw_frame_type, uint8_t flags, 61 SpdyStreamId stream_id, size_t length); 62 63 // Takes the buffer from the SpdyFrameBuilder. take()64 SpdySerializedFrame take() { 65 QUICHE_BUG_IF(spdy_bug_39_1, output_ != nullptr) 66 << "ZeroCopyOutputBuffer is used to build " 67 << "frames. take() shouldn't be called"; 68 QUICHE_BUG_IF(spdy_bug_39_2, kMaxFrameSizeLimit < length_) 69 << "Frame length " << length_ 70 << " is longer than the maximum possible allowed length."; 71 SpdySerializedFrame rv(std::move(buffer_), length()); 72 capacity_ = 0; 73 length_ = 0; 74 offset_ = 0; 75 return rv; 76 } 77 78 // Methods for adding to the payload. These values are appended to the end 79 // of the SpdyFrameBuilder payload. Note - binary integers are converted from 80 // host to network form. WriteUInt8(uint8_t value)81 bool WriteUInt8(uint8_t value) { return WriteBytes(&value, sizeof(value)); } WriteUInt16(uint16_t value)82 bool WriteUInt16(uint16_t value) { 83 value = quiche::QuicheEndian::HostToNet16(value); 84 return WriteBytes(&value, sizeof(value)); 85 } WriteUInt24(uint32_t value)86 bool WriteUInt24(uint32_t value) { 87 value = quiche::QuicheEndian::HostToNet32(value); 88 return WriteBytes(reinterpret_cast<char*>(&value) + 1, sizeof(value) - 1); 89 } WriteUInt32(uint32_t value)90 bool WriteUInt32(uint32_t value) { 91 value = quiche::QuicheEndian::HostToNet32(value); 92 return WriteBytes(&value, sizeof(value)); 93 } WriteUInt64(uint64_t value)94 bool WriteUInt64(uint64_t value) { 95 uint32_t upper = 96 quiche::QuicheEndian::HostToNet32(static_cast<uint32_t>(value >> 32)); 97 uint32_t lower = 98 quiche::QuicheEndian::HostToNet32(static_cast<uint32_t>(value)); 99 return (WriteBytes(&upper, sizeof(upper)) && 100 WriteBytes(&lower, sizeof(lower))); 101 } 102 bool WriteStringPiece32(const absl::string_view value); 103 bool WriteBytes(const void* data, uint32_t data_len); 104 105 private: 106 friend class test::SpdyFrameBuilderPeer; 107 108 // Populates this frame with a HTTP2 frame prefix with type and length 109 // information. 110 bool BeginNewFrameInternal(uint8_t raw_frame_type, uint8_t flags, 111 SpdyStreamId stream_id, size_t length); 112 113 // Returns a writeable buffer of given size in bytes, to be appended to the 114 // currently written frame. Does bounds checking on length but does not 115 // increment the underlying iterator. To do so, consumers should subsequently 116 // call Seek(). 117 // In general, consumers should use Write*() calls instead of this. 118 // Returns NULL on failure. 119 char* GetWritableBuffer(size_t length); 120 char* GetWritableOutput(size_t desired_length, size_t* actual_length); 121 122 // Checks to make sure that there is an appropriate amount of space for a 123 // write of given size, in bytes. 124 bool CanWrite(size_t length) const; 125 126 // A buffer to be created whenever a new frame needs to be written. Used only 127 // if |output_| is nullptr. 128 std::unique_ptr<char[]> buffer_; 129 // A pre-allocated buffer. If not-null, serialized frame data is written to 130 // this buffer. 131 ZeroCopyOutputBuffer* output_ = nullptr; // Does not own. 132 133 size_t capacity_; // Allocation size of payload, set by constructor. 134 size_t length_; // Length of the latest frame in the buffer. 135 size_t offset_; // Position at which the latest frame begins. 136 }; 137 138 } // namespace spdy 139 140 #endif // QUICHE_SPDY_CORE_SPDY_FRAME_BUILDER_H_ 141