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// 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.
#include <cstddef>
#include <cstdint>
#include <memory>
#include <string>
#include <utility>
#include <vector>
#include "absl/strings/string_view.h"
#include "quiche/quic/core/crypto/crypto_handshake_message.h"
#include "quiche/quic/core/crypto/crypto_message_parser.h"
#include "quiche/quic/platform/api/quic_export.h"
namespace quic {
class CryptoFramer;
class QuicData;
class QuicDataWriter;
class QUICHE_EXPORT CryptoFramerVisitorInterface {
virtual ~CryptoFramerVisitorInterface() {}
// Called if an error is detected.
virtual void OnError(CryptoFramer* framer) = 0;
// Called when a complete handshake message has been parsed.
virtual void OnHandshakeMessage(const CryptoHandshakeMessage& message) = 0;
// A class for framing the crypto messages that are exchanged in a QUIC
// session.
class QUICHE_EXPORT CryptoFramer : public CryptoMessageParser {
~CryptoFramer() override;
// ParseMessage parses exactly one message from the given
// absl::string_view. If there is an error, the message is truncated,
// or the message has trailing garbage then nullptr will be returned.
static std::unique_ptr<CryptoHandshakeMessage> ParseMessage(
absl::string_view in);
// Set callbacks to be called from the framer. A visitor must be set, or
// else the framer will crash. It is acceptable for the visitor to do
// nothing. If this is called multiple times, only the last visitor
// will be used. |visitor| will be owned by the framer.
void set_visitor(CryptoFramerVisitorInterface* visitor) {
visitor_ = visitor;
QuicErrorCode error() const override;
const std::string& error_detail() const override;
// Processes input data, which must be delivered in order. Returns
// false if there was an error, and true otherwise. ProcessInput optionally
// takes an EncryptionLevel, but it is ignored. The variant with the
// EncryptionLevel is provided to match the CryptoMessageParser interface.
bool ProcessInput(absl::string_view input, EncryptionLevel level) override;
bool ProcessInput(absl::string_view input);
// Returns the number of bytes of buffered input data remaining to be
// parsed.
size_t InputBytesRemaining() const override;
// Checks if the specified tag has been seen. Returns |true| if it
// has, and |false| if it has not or a CHLO has not been seen.
bool HasTag(QuicTag tag) const;
// Even if the CHLO has not been fully received, force processing of
// the handshake message. This is dangerous and should not be used
// except as a mechanism of last resort.
void ForceHandshake();
// Returns a new QuicData owned by the caller that contains a serialized
// |message|, or nullptr if there was an error.
static std::unique_ptr<QuicData> ConstructHandshakeMessage(
const CryptoHandshakeMessage& message);
// Debug only method which permits processing truncated messages.
void set_process_truncated_messages(bool process_truncated_messages) {
process_truncated_messages_ = process_truncated_messages;
// Clears per-message state. Does not clear the visitor.
void Clear();
// Process does does the work of |ProcessInput|, but returns an error code,
// doesn't set error_ and doesn't call |visitor_->OnError()|.
QuicErrorCode Process(absl::string_view input);
static bool WritePadTag(QuicDataWriter* writer, size_t pad_length,
uint32_t* end_offset);
// Represents the current state of the parsing state machine.
enum CryptoFramerState {
// Visitor to invoke when messages are parsed.
CryptoFramerVisitorInterface* visitor_;
// Last error.
QuicErrorCode error_;
// Remaining unparsed data.
std::string buffer_;
// Current state of the parsing.
CryptoFramerState state_;
// The message currently being parsed.
CryptoHandshakeMessage message_;
// The issue which caused |error_|
std::string error_detail_;
// Number of entires in the message currently being parsed.
uint16_t num_entries_;
// tags_and_lengths_ contains the tags that are currently being parsed and
// their lengths.
std::vector<std::pair<QuicTag, size_t>> tags_and_lengths_;
// Cumulative length of all values in the message currently being parsed.
size_t values_len_;
// Set to true to allow of processing of truncated messages for debugging.
bool process_truncated_messages_;
} // namespace quic