net/quic/crypto/null_encrypter.cc

   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 #include "net/quic/crypto/null_encrypter.h"
   6 #include "net/quic/quic_data_writer.h"
   7 #include "net/quic/quic_utils.h"
   8
   9 using base::StringPiece;
  10 using std::string;
  11
  12 namespace net {
  13
  14 const size_t kHashSizeShort = 12;  // size of uint128 serialized short
  15
  16 NullEncrypter::NullEncrypter() {}
  17
  18 bool NullEncrypter::SetKey(StringPiece key) { return key.empty(); }
  19
  20 bool NullEncrypter::SetNoncePrefix(StringPiece nonce_prefix) {
  21   return nonce_prefix.empty();
  22 }
  23
  24 bool NullEncrypter::EncryptPacket(QuicPacketSequenceNumber /*sequence_number*/,
  25                                   StringPiece associated_data,
  26                                   StringPiece plaintext,
  27                                   char* output,
  28                                   size_t* output_length,
  29                                   size_t max_output_length) {
  30   const size_t len = plaintext.size() + GetHashLength();
  31   if (max_output_length < len) {
  32     return false;
  33   }
  34   uint128 hash = QuicUtils::FNV1a_128_Hash_Two(
  35       associated_data.data(), associated_data.size(), plaintext.data(),
  36       plaintext.size());
  37   QuicUtils::SerializeUint128Short(hash,
  38                                    reinterpret_cast<unsigned char*>(output));
  39   memcpy(output + GetHashLength(), plaintext.data(), plaintext.length());
  40   *output_length = len;
  41   return true;
  42 }
  43
  44 size_t NullEncrypter::GetKeySize() const { return 0; }
  45
  46 size_t NullEncrypter::GetNoncePrefixSize() const { return 0; }
  47
  48 size_t NullEncrypter::GetMaxPlaintextSize(size_t ciphertext_size) const {
  49   return ciphertext_size - GetHashLength();
  50 }
  51
  52 size_t NullEncrypter::GetCiphertextSize(size_t plaintext_size) const {
  53   return plaintext_size + GetHashLength();
  54 }
  55
  56 StringPiece NullEncrypter::GetKey() const { return StringPiece(); }
  57
  58 StringPiece NullEncrypter::GetNoncePrefix() const { return StringPiece(); }
  59
  60 size_t NullEncrypter::GetHashLength() const {
  61   return kHashSizeShort;
  62 }
  63
  64 }  // namespace net