Deprecate HTTP/2 PAD_HIGH field and enforce max padding size to 256 octets.

net/spdy/spdy_protocol.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file contains some protocol structures for use with SPDY 2 and 3
 // The SPDY 2 spec can be found at:
 // http://dev.chromium.org/spdy/spdy-protocol/spdy-protocol-draft2
 // The SPDY 3 spec can be found at:
 // http://dev.chromium.org/spdy/spdy-protocol/spdy-protocol-draft3
 
@@ skipping 37 matching lines @@
 
 // Initial window size for a Spdy stream in bytes.
 const int32 kSpdyStreamInitialWindowSize = 64 * 1024;  // 64 KBytes
 
 // Initial window size for a Spdy session in bytes.
 const int32 kSpdySessionInitialWindowSize = 64 * 1024;  // 64 KBytes
 
 // Maximum window size for a Spdy stream or session.
 const int32 kSpdyMaximumWindowSize = 0x7FFFFFFF;  // Max signed 32bit int
 
+// Maximum padding size in octets for one DATA or HEADERS or PUSH_PROMISE frame.
+const int32 kPaddingSizePerFrame = 256;
+
 // SPDY 2 dictionary.
 // This is just a hacked dictionary to use for shrinking HTTP-like headers.
 const char kV2Dictionary[] =
   "optionsgetheadpostputdeletetraceacceptaccept-charsetaccept-encodingaccept-"
   "languageauthorizationexpectfromhostif-modified-sinceif-matchif-none-matchi"
   "f-rangeif-unmodifiedsincemax-forwardsproxy-authorizationrangerefererteuser"
   "-agent10010120020120220320420520630030130230330430530630740040140240340440"
   "5406407408409410411412413414415416417500501502503504505accept-rangesageeta"
   "glocationproxy-authenticatepublicretry-afterservervarywarningwww-authentic"
   "ateallowcontent-basecontent-encodingcache-controlconnectiondatetrailertran"
@@ skipping 219 matching lines @@
   CONTINUATION,
   ALTSVC,
   PRIORITY
 };
 
 // Flags on data packets.
 enum SpdyDataFlags {
   DATA_FLAG_NONE = 0x00,
   DATA_FLAG_FIN = 0x01,
   DATA_FLAG_END_SEGMENT = 0x02,
-  DATA_FLAG_PAD_LOW = 0x08,
-  DATA_FLAG_PAD_HIGH = 0x10,
+  DATA_FLAG_PADDED = 0x08,
   DATA_FLAG_COMPRESSED = 0x20,
 };
 
 // Flags on control packets
 enum SpdyControlFlags {
   CONTROL_FLAG_NONE = 0x00,
   CONTROL_FLAG_FIN = 0x01,
   CONTROL_FLAG_UNIDIRECTIONAL = 0x02,
 };
 
 enum SpdyPingFlags {
   PING_FLAG_ACK = 0x01,
 };
 
 // Used by HEADERS, PUSH_PROMISE, and CONTINUATION.
 enum SpdyHeadersFlags {
   HEADERS_FLAG_END_SEGMENT = 0x02,
   HEADERS_FLAG_END_HEADERS = 0x04,
-  HEADERS_FLAG_PAD_LOW = 0x08,
-  HEADERS_FLAG_PAD_HIGH = 0x10,
+  HEADERS_FLAG_PADDED = 0x08,
   HEADERS_FLAG_PRIORITY = 0x20,
 };
 
 enum SpdyPushPromiseFlags {
   PUSH_PROMISE_FLAG_END_PUSH_PROMISE = 0x04,
+  PUSH_PROMISE_FLAG_PADDED = 0x08,
 };
 
 // Flags on the SETTINGS control frame.
 enum SpdySettingsControlFlags {
   SETTINGS_FLAG_CLEAR_PREVIOUSLY_PERSISTED_SETTINGS = 0x01,
 };
 
 enum Http2SettingsControlFlags {
   SETTINGS_FLAG_ACK = 0x01,
 };
@@ skipping 280 matching lines @@
   // Performs deep copy on data.
   SpdyDataIR(SpdyStreamId stream_id, const base::StringPiece& data);
 
   // Use in conjunction with SetDataShallow() for shallow-copy on data.
   explicit SpdyDataIR(SpdyStreamId stream_id);
 
   virtual ~SpdyDataIR();
 
   base::StringPiece data() const { return data_; }
 
-  bool pad_low() const { return pad_low_; }
-
-  bool pad_high() const { return pad_high_; }
+  bool padded() const { return padded_; }
 
   int padding_payload_len() const { return padding_payload_len_; }
 
   void set_padding_len(int padding_len) {
-    // The padding_len should be in (0, 65535 + 2].
-    // Note that SpdyFramer::GetDataFrameMaximumPayload() enforces the overall
-    // payload size later so we actually can't pad more than 16375 bytes.
     DCHECK_GT(padding_len, 0);
-    DCHECK_LT(padding_len, 65537);
-
-    if (padding_len <= 256) {
-      pad_low_ = true;
-      --padding_len;
-    } else {
-      pad_low_ = pad_high_ = true;
-      padding_len -= 2;
-    }
-    padding_payload_len_ = padding_len;
+    DCHECK_LE(padding_len, kPaddingSizePerFrame);
+    padded_ = true;
+    // The pad field takes one octet on the wire.
+    padding_payload_len_ = padding_len - 1;
   }
 
   // Deep-copy of data (keep private copy).
   void SetDataDeep(const base::StringPiece& data) {
     data_store_.reset(new std::string(data.data(), data.length()));
     data_ = *(data_store_.get());
   }
 
   // Shallow-copy of data (do not keep private copy).
   void SetDataShallow(const base::StringPiece& data) {
     data_store_.reset();
     data_ = data;
   }
 
   virtual void Visit(SpdyFrameVisitor* visitor) const OVERRIDE;
 
  private:
   // Used to store data that this SpdyDataIR should own.
   scoped_ptr<std::string> data_store_;
   base::StringPiece data_;
 
-  bool pad_low_;
-  bool pad_high_;
+  bool padded_;
   // padding_payload_len_ = desired padding length - len(padding length field).
   int padding_payload_len_;
 
   DISALLOW_COPY_AND_ASSIGN(SpdyDataIR);
 };
 
 class NET_EXPORT_PRIVATE SpdySynStreamIR
     : public SpdyFrameWithNameValueBlockIR {
  public:
   explicit SpdySynStreamIR(SpdyStreamId stream_id)
@@ skipping 373 matching lines @@
   SpdyFrameVisitor() {}
   virtual ~SpdyFrameVisitor() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SpdyFrameVisitor);
 };
 
 }  // namespace net
 
 #endif  // NET_SPDY_SPDY_PROTOCOL_H_