net/quic/crypto/crypto_handshake_message.h

   1 // Copyright (c) 2013 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 NET_QUIC_CRYPTO_CRYPTO_HANDSHAKE_MESSAGE_H_
   6 #define NET_QUIC_CRYPTO_CRYPTO_HANDSHAKE_MESSAGE_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/memory/scoped_ptr.h"
  12 #include "base/strings/string_piece.h"
  13 #include "net/base/net_export.h"
  14 #include "net/quic/quic_protocol.h"
  15
  16 namespace net {
  17
  18 // An intermediate format of a handshake message that's convenient for a
  19 // CryptoFramer to serialize from or parse into.
  20 class NET_EXPORT_PRIVATE CryptoHandshakeMessage {
  21  public:
  22   CryptoHandshakeMessage();
  23   CryptoHandshakeMessage(const CryptoHandshakeMessage& other);
  24   ~CryptoHandshakeMessage();
  25
  26   CryptoHandshakeMessage& operator=(const CryptoHandshakeMessage& other);
  27
  28   // Clears state.
  29   void Clear();
  30
  31   // GetSerialized returns the serialized form of this message and caches the
  32   // result. Subsequently altering the message does not invalidate the cache.
  33   const QuicData& GetSerialized() const;
  34
  35   // MarkDirty invalidates the cache created by |GetSerialized|.
  36   void MarkDirty();
  37
  38   // SetValue sets an element with the given tag to the raw, memory contents of
  39   // |v|.
  40   template<class T> void SetValue(QuicTag tag, const T& v) {
  41     tag_value_map_[tag] =
  42         std::string(reinterpret_cast<const char*>(&v), sizeof(v));
  43   }
  44
  45   // SetVector sets an element with the given tag to the raw contents of an
  46   // array of elements in |v|.
  47   template<class T> void SetVector(QuicTag tag, const std::vector<T>& v) {
  48     if (v.empty()) {
  49       tag_value_map_[tag] = std::string();
  50     } else {
  51       tag_value_map_[tag] = std::string(reinterpret_cast<const char*>(&v[0]),
  52                                         v.size() * sizeof(T));
  53     }
  54   }
  55
  56   // Returns the message tag.
  57   QuicTag tag() const { return tag_; }
  58   // Sets the message tag.
  59   void set_tag(QuicTag tag) { tag_ = tag; }
  60
  61   const QuicTagValueMap& tag_value_map() const { return tag_value_map_; }
  62
  63   // SetTaglist sets an element with the given tag to contain a list of tags,
  64   // passed as varargs. The argument list must be terminated with a 0 element.
  65   void SetTaglist(QuicTag tag, ...);
  66
  67   void SetStringPiece(QuicTag tag, base::StringPiece value);
  68
  69   // Erase removes a tag/value, if present, from the message.
  70   void Erase(QuicTag tag);
  71
  72   // GetTaglist finds an element with the given tag containing zero or more
  73   // tags. If such a tag doesn't exist, it returns false. Otherwise it sets
  74   // |out_tags| and |out_len| to point to the array of tags and returns true.
  75   // The array points into the CryptoHandshakeMessage and is valid only for as
  76   // long as the CryptoHandshakeMessage exists and is not modified.
  77   QuicErrorCode GetTaglist(QuicTag tag, const QuicTag** out_tags,
  78                            size_t* out_len) const;
  79
  80   bool GetStringPiece(QuicTag tag, base::StringPiece* out) const;
  81
  82   // GetNthValue24 interprets the value with the given tag to be a series of
  83   // 24-bit, length prefixed values and it returns the subvalue with the given
  84   // index.
  85   QuicErrorCode GetNthValue24(QuicTag tag,
  86                               unsigned index,
  87                               base::StringPiece* out) const;
  88   QuicErrorCode GetUint32(QuicTag tag, uint32* out) const;
  89   QuicErrorCode GetUint64(QuicTag tag, uint64* out) const;
  90
  91   // size returns 4 (message tag) + 2 (uint16, number of entries) +
  92   // (4 (tag) + 4 (end offset))*tag_value_map_.size() + ∑ value sizes.
  93   size_t size() const;
  94
  95   // set_minimum_size sets the minimum number of bytes that the message should
  96   // consume. The CryptoFramer will add a PAD tag as needed when serializing in
  97   // order to ensure this. Setting a value of 0 disables padding.
  98   //
  99   // Padding is useful in order to ensure that messages are a minimum size. A
 100   // QUIC server can require a minimum size in order to reduce the
 101   // amplification factor of any mirror DoS attack.
 102   void set_minimum_size(size_t min_bytes);
 103
 104   size_t minimum_size() const;
 105
 106   // DebugString returns a multi-line, string representation of the message
 107   // suitable for including in debug output.
 108   std::string DebugString() const;
 109
 110  private:
 111   // GetPOD is a utility function for extracting a plain-old-data value. If
 112   // |tag| exists in the message, and has a value of exactly |len| bytes then
 113   // it copies |len| bytes of data into |out|. Otherwise |len| bytes at |out|
 114   // are zeroed out.
 115   //
 116   // If used to copy integers then this assumes that the machine is
 117   // little-endian.
 118   QuicErrorCode GetPOD(QuicTag tag, void* out, size_t len) const;
 119
 120   std::string DebugStringInternal(size_t indent) const;
 121
 122   QuicTag tag_;
 123   QuicTagValueMap tag_value_map_;
 124
 125   size_t minimum_size_;
 126
 127   // The serialized form of the handshake message. This member is constructed
 128   // lasily.
 129   mutable scoped_ptr<QuicData> serialized_;
 130 };
 131
 132 }  // namespace net
 133
 134 #endif  // NET_QUIC_CRYPTO_CRYPTO_HANDSHAKE_MESSAGE_H_