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/*
* libjingle
* Copyright 2011, Google Inc.
* Copyright 2011, RTFM, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef TALK_P2P_BASE_DTLSTRANSPORTCHANNEL_H_
#define TALK_P2P_BASE_DTLSTRANSPORTCHANNEL_H_
#include <string>
#include <vector>
#include "talk/base/buffer.h"
#include "talk/base/scoped_ptr.h"
#include "talk/base/sslstreamadapter.h"
#include "talk/base/stream.h"
#include "talk/p2p/base/transportchannelimpl.h"
namespace cricket {
// A bridge between a packet-oriented/channel-type interface on
// the bottom and a StreamInterface on the top.
class StreamInterfaceChannel : public talk_base::StreamInterface,
public sigslot::has_slots<> {
public:
StreamInterfaceChannel(talk_base::Thread* owner, TransportChannel* channel)
: channel_(channel),
state_(talk_base::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 talk_base::StreamState GetState() const { return state_; }
virtual void Close() { state_ = talk_base::SS_CLOSED; }
virtual talk_base::StreamResult Read(void* buffer, size_t buffer_len,
size_t* read, int* error);
virtual talk_base::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(talk_base::StreamInterface* stream, int sig, int err);
TransportChannel* channel_; // owned by DtlsTransportChannelWrapper
talk_base::StreamState state_;
talk_base::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(talk_base::SSLIdentity *identity);
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,
talk_base::DiffServCodePoint dscp,
int flags);
// TransportChannel calls that we forward to the wrapped transport.
virtual int SetOption(talk_base::Socket::Option opt, int value) {
return channel_->SetOption(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(talk_base::SSLRole* role) const;
virtual bool SetSslRole(talk_base::SSLRole role);
// 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 void SetIceTiebreaker(uint64 tiebreaker) {
channel_->SetIceTiebreaker(tiebreaker);
}
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,
int flags);
void OnReadyToSend(TransportChannel* channel);
void OnDtlsEvent(talk_base::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);
Transport* transport_; // The transport_ that created us.
talk_base::Thread* worker_thread_; // Everything should occur on this thread.
TransportChannelImpl* channel_; // Underlying channel, owned by transport_.
talk_base::scoped_ptr<talk_base::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_;
talk_base::SSLIdentity* local_identity_;
talk_base::SSLRole ssl_role_;
talk_base::Buffer remote_fingerprint_value_;
std::string remote_fingerprint_algorithm_;
DISALLOW_COPY_AND_ASSIGN(DtlsTransportChannelWrapper);
};
} // namespace cricket
#endif // TALK_P2P_BASE_DTLSTRANSPORTCHANNEL_H_