252 lines
9.8 KiB
C
252 lines
9.8 KiB
C
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/*
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* Copyright 2011 The WebRTC Project Authors. All rights reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef WEBRTC_P2P_BASE_DTLSTRANSPORTCHANNEL_H_
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#define WEBRTC_P2P_BASE_DTLSTRANSPORTCHANNEL_H_
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#include <memory>
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#include <string>
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#include <vector>
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#include "webrtc/p2p/base/transportchannelimpl.h"
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#include "webrtc/base/buffer.h"
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#include "webrtc/base/bufferqueue.h"
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#include "webrtc/base/constructormagic.h"
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#include "webrtc/base/sslstreamadapter.h"
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#include "webrtc/base/stream.h"
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namespace cricket {
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// A bridge between a packet-oriented/channel-type interface on
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// the bottom and a StreamInterface on the top.
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class StreamInterfaceChannel : public rtc::StreamInterface {
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public:
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explicit StreamInterfaceChannel(TransportChannel* channel);
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// Push in a packet; this gets pulled out from Read().
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bool OnPacketReceived(const char* data, size_t size);
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// Implementations of StreamInterface
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rtc::StreamState GetState() const override { return state_; }
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void Close() override;
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rtc::StreamResult Read(void* buffer,
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size_t buffer_len,
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size_t* read,
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int* error) override;
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rtc::StreamResult Write(const void* data,
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size_t data_len,
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size_t* written,
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int* error) override;
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private:
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TransportChannel* channel_; // owned by DtlsTransportChannelWrapper
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rtc::StreamState state_;
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rtc::BufferQueue packets_;
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RTC_DISALLOW_COPY_AND_ASSIGN(StreamInterfaceChannel);
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};
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// This class provides a DTLS SSLStreamAdapter inside a TransportChannel-style
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// packet-based interface, wrapping an existing TransportChannel instance
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// (e.g a P2PTransportChannel)
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// Here's the way this works:
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//
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// DtlsTransportChannelWrapper {
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// SSLStreamAdapter* dtls_ {
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// StreamInterfaceChannel downward_ {
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// TransportChannelImpl* channel_;
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// }
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// }
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// }
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//
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// - Data which comes into DtlsTransportChannelWrapper from the underlying
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// channel_ via OnReadPacket() is checked for whether it is DTLS
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// or not, and if it is, is passed to DtlsTransportChannelWrapper::
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// HandleDtlsPacket, which pushes it into to downward_.
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// dtls_ is listening for events on downward_, so it immediately calls
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// downward_->Read().
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//
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// - Data written to DtlsTransportChannelWrapper is passed either to
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// downward_ or directly to channel_, depending on whether DTLS is
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// negotiated and whether the flags include PF_SRTP_BYPASS
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//
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// - The SSLStreamAdapter writes to downward_->Write()
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// which translates it into packet writes on channel_.
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class DtlsTransportChannelWrapper : public TransportChannelImpl {
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public:
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// The parameters here are:
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// channel -- the TransportChannel we are wrapping
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explicit DtlsTransportChannelWrapper(TransportChannelImpl* channel);
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~DtlsTransportChannelWrapper() override;
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void SetIceRole(IceRole role) override { channel_->SetIceRole(role); }
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IceRole GetIceRole() const override { return channel_->GetIceRole(); }
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bool SetLocalCertificate(
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const rtc::scoped_refptr<rtc::RTCCertificate>& certificate) override;
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rtc::scoped_refptr<rtc::RTCCertificate> GetLocalCertificate() const override;
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bool SetRemoteFingerprint(const std::string& digest_alg,
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const uint8_t* digest,
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size_t digest_len) override;
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// Returns false if no local certificate was set, or if the peer doesn't
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// support DTLS.
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bool IsDtlsActive() const override { return dtls_active_; }
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// Called to send a packet (via DTLS, if turned on).
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int SendPacket(const char* data,
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size_t size,
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const rtc::PacketOptions& options,
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int flags) override;
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// TransportChannel calls that we forward to the wrapped transport.
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int SetOption(rtc::Socket::Option opt, int value) override {
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return channel_->SetOption(opt, value);
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}
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bool GetOption(rtc::Socket::Option opt, int* value) override {
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return channel_->GetOption(opt, value);
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}
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int GetError() override { return channel_->GetError(); }
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bool GetStats(ConnectionInfos* infos) override {
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return channel_->GetStats(infos);
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}
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const std::string SessionId() const override { return channel_->SessionId(); }
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virtual bool SetSslMaxProtocolVersion(rtc::SSLProtocolVersion version);
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// Set up the ciphers to use for DTLS-SRTP. If this method is not called
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// before DTLS starts, or |ciphers| is empty, SRTP keys won't be negotiated.
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// This method should be called before SetupDtls.
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bool SetSrtpCryptoSuites(const std::vector<int>& ciphers) override;
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// Find out which DTLS-SRTP cipher was negotiated
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bool GetSrtpCryptoSuite(int* cipher) override;
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bool GetSslRole(rtc::SSLRole* role) const override;
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bool SetSslRole(rtc::SSLRole role) override;
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// Find out which DTLS cipher was negotiated
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bool GetSslCipherSuite(int* cipher) override;
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// Once DTLS has been established, this method retrieves the certificate in
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// use by the remote peer, for use in external identity verification.
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std::unique_ptr<rtc::SSLCertificate> GetRemoteSSLCertificate() const override;
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// Once DTLS has established (i.e., this channel is writable), this method
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// extracts the keys negotiated during the DTLS handshake, for use in external
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// encryption. DTLS-SRTP uses this to extract the needed SRTP keys.
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// See the SSLStreamAdapter documentation for info on the specific parameters.
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bool ExportKeyingMaterial(const std::string& label,
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const uint8_t* context,
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size_t context_len,
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bool use_context,
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uint8_t* result,
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size_t result_len) override {
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return (dtls_.get()) ? dtls_->ExportKeyingMaterial(label, context,
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context_len,
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use_context,
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result, result_len)
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: false;
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}
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// TransportChannelImpl calls.
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TransportChannelState GetState() const override {
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return channel_->GetState();
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}
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void SetIceTiebreaker(uint64_t tiebreaker) override {
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channel_->SetIceTiebreaker(tiebreaker);
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}
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void SetIceCredentials(const std::string& ice_ufrag,
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const std::string& ice_pwd) override {
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channel_->SetIceCredentials(ice_ufrag, ice_pwd);
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}
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void SetRemoteIceCredentials(const std::string& ice_ufrag,
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const std::string& ice_pwd) override {
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channel_->SetRemoteIceCredentials(ice_ufrag, ice_pwd);
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}
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void SetRemoteIceMode(IceMode mode) override {
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channel_->SetRemoteIceMode(mode);
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}
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void Connect() override;
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void MaybeStartGathering() override { channel_->MaybeStartGathering(); }
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IceGatheringState gathering_state() const override {
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return channel_->gathering_state();
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}
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void AddRemoteCandidate(const Candidate& candidate) override {
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channel_->AddRemoteCandidate(candidate);
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}
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void RemoveRemoteCandidate(const Candidate& candidate) override {
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channel_->RemoveRemoteCandidate(candidate);
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}
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void SetIceConfig(const IceConfig& config) override {
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channel_->SetIceConfig(config);
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}
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// Needed by DtlsTransport.
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TransportChannelImpl* channel() { return channel_; }
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private:
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void OnReadableState(TransportChannel* channel);
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void OnWritableState(TransportChannel* channel);
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void OnReadPacket(TransportChannel* channel, const char* data, size_t size,
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const rtc::PacketTime& packet_time, int flags);
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void OnSentPacket(TransportChannel* channel,
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const rtc::SentPacket& sent_packet);
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void OnReadyToSend(TransportChannel* channel);
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void OnReceivingState(TransportChannel* channel);
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void OnDtlsEvent(rtc::StreamInterface* stream_, int sig, int err);
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bool SetupDtls();
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bool MaybeStartDtls();
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bool HandleDtlsPacket(const char* data, size_t size);
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void OnGatheringState(TransportChannelImpl* channel);
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void OnCandidateGathered(TransportChannelImpl* channel, const Candidate& c);
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void OnCandidatesRemoved(TransportChannelImpl* channel,
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const Candidates& candidates);
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void OnRoleConflict(TransportChannelImpl* channel);
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void OnRouteChange(TransportChannel* channel, const Candidate& candidate);
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void OnSelectedCandidatePairChanged(
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TransportChannel* channel,
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CandidatePairInterface* selected_candidate_pair,
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int last_sent_packet_id);
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void OnChannelStateChanged(TransportChannelImpl* channel);
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void Reconnect();
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rtc::Thread* worker_thread_; // Everything should occur on this thread.
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// Underlying channel, not owned by this class.
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TransportChannelImpl* const channel_;
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std::unique_ptr<rtc::SSLStreamAdapter> dtls_; // The DTLS stream
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StreamInterfaceChannel* downward_; // Wrapper for channel_, owned by dtls_.
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std::vector<int> srtp_ciphers_; // SRTP ciphers to use with DTLS.
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bool dtls_active_ = false;
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rtc::scoped_refptr<rtc::RTCCertificate> local_certificate_;
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rtc::SSLRole ssl_role_;
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rtc::SSLProtocolVersion ssl_max_version_;
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rtc::Buffer remote_fingerprint_value_;
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std::string remote_fingerprint_algorithm_;
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// Cached DTLS ClientHello packet that was received before we started the
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// DTLS handshake. This could happen if the hello was received before the
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// transport channel became writable, or before a remote fingerprint was
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// received.
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rtc::Buffer cached_client_hello_;
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RTC_DISALLOW_COPY_AND_ASSIGN(DtlsTransportChannelWrapper);
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};
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} // namespace cricket
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#endif // WEBRTC_P2P_BASE_DTLSTRANSPORTCHANNEL_H_
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