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/*
* Copyright 2011 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 WEBRTC_P2P_BASE_DTLSTRANSPORTCHANNEL_H_
#define WEBRTC_P2P_BASE_DTLSTRANSPORTCHANNEL_H_
#include <string>
#include <vector>
#include "webrtc/p2p/base/transportchannelimpl.h"
#include "webrtc/base/buffer.h"
#include "webrtc/base/scoped_ptr.h"
#include "webrtc/base/sslstreamadapter.h"
#include "webrtc/base/stream.h"
namespace cricket {
// A bridge between a packet-oriented/channel-type interface on
// the bottom and a StreamInterface on the top.
class StreamInterfaceChannel : public rtc::StreamInterface,
public sigslot::has_slots<> {
public:
StreamInterfaceChannel(rtc::Thread* owner, TransportChannel* channel)
: channel_(channel),
state_(rtc::SS_OPEN),
fifo_(kFifoSize, owner) {
fifo_.SignalEvent.connect(this, &StreamInterfaceChannel::OnEvent);
}
// Push in a packet; this gets pulled out from Read().
bool OnPacketReceived(const char* data, size_t size);
// Implementations of StreamInterface
virtual rtc::StreamState GetState() const { return state_; }
virtual void Close() { state_ = rtc::SS_CLOSED; }
virtual rtc::StreamResult Read(void* buffer, size_t buffer_len,
size_t* read, int* error);
virtual rtc::StreamResult Write(const void* data, size_t data_len,
size_t* written, int* error);
private:
static const size_t kFifoSize = 8192;
// Forward events
virtual void OnEvent(rtc::StreamInterface* stream, int sig, int err);
TransportChannel* channel_; // owned by DtlsTransportChannelWrapper
rtc::StreamState state_;
rtc::FifoBuffer fifo_;
DISALLOW_COPY_AND_ASSIGN(StreamInterfaceChannel);
};
// This class provides a DTLS SSLStreamAdapter inside a TransportChannel-style
// packet-based interface, wrapping an existing TransportChannel instance
// (e.g a P2PTransportChannel)
// Here's the way this works:
//
// DtlsTransportChannelWrapper {
// SSLStreamAdapter* dtls_ {
// StreamInterfaceChannel downward_ {
// TransportChannelImpl* channel_;
// }
// }
// }
//
// - Data which comes into DtlsTransportChannelWrapper from the underlying
// channel_ via OnReadPacket() is checked for whether it is DTLS
// or not, and if it is, is passed to DtlsTransportChannelWrapper::
// HandleDtlsPacket, which pushes it into to downward_.
// dtls_ is listening for events on downward_, so it immediately calls
// downward_->Read().
//
// - Data written to DtlsTransportChannelWrapper is passed either to
// downward_ or directly to channel_, depending on whether DTLS is
// negotiated and whether the flags include PF_SRTP_BYPASS
//
// - The SSLStreamAdapter writes to downward_->Write()
// which translates it into packet writes on channel_.
class DtlsTransportChannelWrapper : public TransportChannelImpl {
public:
enum State {
STATE_NONE, // No state or rejected.
STATE_OFFERED, // Our identity has been set.
STATE_ACCEPTED, // The other side sent a fingerprint.
STATE_STARTED, // We are negotiating.
STATE_OPEN, // Negotiation complete.
STATE_CLOSED // Connection closed.
};
// The parameters here are:
// transport -- the DtlsTransport that created us
// channel -- the TransportChannel we are wrapping
DtlsTransportChannelWrapper(Transport* transport,
TransportChannelImpl* channel);
virtual ~DtlsTransportChannelWrapper();
virtual void SetIceRole(IceRole role) {
channel_->SetIceRole(role);
}
virtual IceRole GetIceRole() const {
return channel_->GetIceRole();
}
virtual bool SetLocalIdentity(rtc::SSLIdentity *identity);
virtual bool GetLocalIdentity(rtc::SSLIdentity** identity) const;
virtual bool SetRemoteFingerprint(const std::string& digest_alg,
const uint8* digest,
size_t digest_len);
virtual bool IsDtlsActive() const { return dtls_state_ != STATE_NONE; }
// Called to send a packet (via DTLS, if turned on).
virtual int SendPacket(const char* data, size_t size,
const rtc::PacketOptions& options,
int flags);
// TransportChannel calls that we forward to the wrapped transport.
virtual int SetOption(rtc::Socket::Option opt, int value) {
return channel_->SetOption(opt, value);
}
virtual bool GetOption(rtc::Socket::Option opt, int* value) {
return channel_->GetOption(opt, value);
}
virtual int GetError() {
return channel_->GetError();
}
virtual bool GetStats(ConnectionInfos* infos) {
return channel_->GetStats(infos);
}
virtual const std::string SessionId() const {
return channel_->SessionId();
}
// Set up the ciphers to use for DTLS-SRTP. If this method is not called
// before DTLS starts, or |ciphers| is empty, SRTP keys won't be negotiated.
// This method should be called before SetupDtls.
virtual bool SetSrtpCiphers(const std::vector<std::string>& ciphers);
// Find out which DTLS-SRTP cipher was negotiated
virtual bool GetSrtpCipher(std::string* cipher);
virtual bool GetSslRole(rtc::SSLRole* role) const;
virtual bool SetSslRole(rtc::SSLRole role);
// Find out which DTLS cipher was negotiated
virtual bool GetSslCipher(std::string* cipher);
// Once DTLS has been established, this method retrieves the certificate in
// use by the remote peer, for use in external identity verification.
virtual bool GetRemoteCertificate(rtc::SSLCertificate** cert) const;
// Once DTLS has established (i.e., this channel is writable), this method
// extracts the keys negotiated during the DTLS handshake, for use in external
// encryption. DTLS-SRTP uses this to extract the needed SRTP keys.
// See the SSLStreamAdapter documentation for info on the specific parameters.
virtual bool ExportKeyingMaterial(const std::string& label,
const uint8* context,
size_t context_len,
bool use_context,
uint8* result,
size_t result_len) {
return (dtls_.get()) ? dtls_->ExportKeyingMaterial(label, context,
context_len,
use_context,
result, result_len)
: false;
}
// TransportChannelImpl calls.
virtual Transport* GetTransport() {
return transport_;
}
virtual TransportChannelState GetState() const {
return channel_->GetState();
}
virtual void SetIceTiebreaker(uint64 tiebreaker) {
channel_->SetIceTiebreaker(tiebreaker);
}
virtual bool GetIceProtocolType(IceProtocolType* type) const {
return channel_->GetIceProtocolType(type);
}
virtual void SetIceProtocolType(IceProtocolType type) {
channel_->SetIceProtocolType(type);
}
virtual void SetIceCredentials(const std::string& ice_ufrag,
const std::string& ice_pwd) {
channel_->SetIceCredentials(ice_ufrag, ice_pwd);
}
virtual void SetRemoteIceCredentials(const std::string& ice_ufrag,
const std::string& ice_pwd) {
channel_->SetRemoteIceCredentials(ice_ufrag, ice_pwd);
}
virtual void SetRemoteIceMode(IceMode mode) {
channel_->SetRemoteIceMode(mode);
}
virtual void Connect();
virtual void Reset();
virtual void OnSignalingReady() {
channel_->OnSignalingReady();
}
virtual void OnCandidate(const Candidate& candidate) {
channel_->OnCandidate(candidate);
}
// Needed by DtlsTransport.
TransportChannelImpl* channel() { return channel_; }
private:
void OnReadableState(TransportChannel* channel);
void OnWritableState(TransportChannel* channel);
void OnReadPacket(TransportChannel* channel, const char* data, size_t size,
const rtc::PacketTime& packet_time, int flags);
void OnReadyToSend(TransportChannel* channel);
void OnDtlsEvent(rtc::StreamInterface* stream_, int sig, int err);
bool SetupDtls();
bool MaybeStartDtls();
bool HandleDtlsPacket(const char* data, size_t size);
void OnRequestSignaling(TransportChannelImpl* channel);
void OnCandidateReady(TransportChannelImpl* channel, const Candidate& c);
void OnCandidatesAllocationDone(TransportChannelImpl* channel);
void OnRoleConflict(TransportChannelImpl* channel);
void OnRouteChange(TransportChannel* channel, const Candidate& candidate);
void OnConnectionRemoved(TransportChannelImpl* channel);
Transport* transport_; // The transport_ that created us.
rtc::Thread* worker_thread_; // Everything should occur on this thread.
TransportChannelImpl* channel_; // Underlying channel, owned by transport_.
rtc::scoped_ptr<rtc::SSLStreamAdapter> dtls_; // The DTLS stream
StreamInterfaceChannel* downward_; // Wrapper for channel_, owned by dtls_.
std::vector<std::string> srtp_ciphers_; // SRTP ciphers to use with DTLS.
State dtls_state_;
rtc::SSLIdentity* local_identity_;
rtc::SSLRole ssl_role_;
rtc::Buffer remote_fingerprint_value_;
std::string remote_fingerprint_algorithm_;
DISALLOW_COPY_AND_ASSIGN(DtlsTransportChannelWrapper);
};
} // namespace cricket
#endif // WEBRTC_P2P_BASE_DTLSTRANSPORTCHANNEL_H_