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/*
* Copyright 2009 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef PC_SRTPFILTER_H_
#define PC_SRTPFILTER_H_
#include <list>
#include <map>
#include <memory>
#include <string>
#include <vector>
#include "absl/types/optional.h"
#include "api/array_view.h"
#include "api/cryptoparams.h"
#include "api/jsep.h"
#include "pc/sessiondescription.h"
#include "rtc_base/buffer.h"
#include "rtc_base/constructormagic.h"
#include "rtc_base/criticalsection.h"
#include "rtc_base/sslstreamadapter.h"
#include "rtc_base/thread_checker.h"
// Forward declaration to avoid pulling in libsrtp headers here
struct srtp_event_data_t;
struct srtp_ctx_t_;
namespace cricket {
// A helper class used to negotiate SDES crypto params.
// TODO(zhihuang): Find a better name for this class, like "SdesNegotiator".
class SrtpFilter {
public:
enum Mode { PROTECT, UNPROTECT };
enum Error {
ERROR_NONE,
ERROR_FAIL,
ERROR_AUTH,
ERROR_REPLAY,
};
SrtpFilter();
~SrtpFilter();
// Whether the filter is active (i.e. crypto has been properly negotiated).
bool IsActive() const;
// Handle the offer/answer negotiation of the crypto parameters internally.
// TODO(zhihuang): Make SetOffer/ProvisionalAnswer/Answer private as helper
// methods once start using Process.
bool Process(const std::vector<CryptoParams>& cryptos,
webrtc::SdpType type,
ContentSource source);
// Indicates which crypto algorithms and keys were contained in the offer.
// offer_params should contain a list of available parameters to use, or none,
// if crypto is not desired. This must be called before SetAnswer.
bool SetOffer(const std::vector<CryptoParams>& offer_params,
ContentSource source);
// Same as SetAnwer. But multiple calls are allowed to SetProvisionalAnswer
// after a call to SetOffer.
bool SetProvisionalAnswer(const std::vector<CryptoParams>& answer_params,
ContentSource source);
// Indicates which crypto algorithms and keys were contained in the answer.
// answer_params should contain the negotiated parameters, which may be none,
// if crypto was not desired or could not be negotiated (and not required).
// This must be called after SetOffer. If crypto negotiation completes
// successfully, this will advance the filter to the active state.
bool SetAnswer(const std::vector<CryptoParams>& answer_params,
ContentSource source);
bool ResetParams();
absl::optional<int> send_cipher_suite() { return send_cipher_suite_; }
absl::optional<int> recv_cipher_suite() { return recv_cipher_suite_; }
rtc::ArrayView<const uint8_t> send_key() { return send_key_; }
rtc::ArrayView<const uint8_t> recv_key() { return recv_key_; }
protected:
bool ExpectOffer(ContentSource source);
bool StoreParams(const std::vector<CryptoParams>& params,
ContentSource source);
bool ExpectAnswer(ContentSource source);
bool DoSetAnswer(const std::vector<CryptoParams>& answer_params,
ContentSource source,
bool final);
bool NegotiateParams(const std::vector<CryptoParams>& answer_params,
CryptoParams* selected_params);
private:
bool ApplySendParams(const CryptoParams& send_params);
bool ApplyRecvParams(const CryptoParams& recv_params);
static bool ParseKeyParams(const std::string& params,
uint8_t* key,
size_t len);
enum State {
ST_INIT, // SRTP filter unused.
ST_SENTOFFER, // Offer with SRTP parameters sent.
ST_RECEIVEDOFFER, // Offer with SRTP parameters received.
ST_SENTPRANSWER_NO_CRYPTO, // Sent provisional answer without crypto.
// Received provisional answer without crypto.
ST_RECEIVEDPRANSWER_NO_CRYPTO,
ST_ACTIVE, // Offer and answer set.
// SRTP filter is active but new parameters are offered.
// When the answer is set, the state transitions to ST_ACTIVE or ST_INIT.
ST_SENTUPDATEDOFFER,
// SRTP filter is active but new parameters are received.
// When the answer is set, the state transitions back to ST_ACTIVE.
ST_RECEIVEDUPDATEDOFFER,
// SRTP filter is active but the sent answer is only provisional.
// When the final answer is set, the state transitions to ST_ACTIVE or
// ST_INIT.
ST_SENTPRANSWER,
// SRTP filter is active but the received answer is only provisional.
// When the final answer is set, the state transitions to ST_ACTIVE or
// ST_INIT.
ST_RECEIVEDPRANSWER
};
State state_ = ST_INIT;
std::vector<CryptoParams> offer_params_;
CryptoParams applied_send_params_;
CryptoParams applied_recv_params_;
absl::optional<int> send_cipher_suite_;
absl::optional<int> recv_cipher_suite_;
rtc::ZeroOnFreeBuffer<uint8_t> send_key_;
rtc::ZeroOnFreeBuffer<uint8_t> recv_key_;
};
} // namespace cricket
#endif // PC_SRTPFILTER_H_
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