Create QuicTransportChannel

webrtc/p2p/quic/quictransportchannel.cc

+/*
+ *  Copyright 2016 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.
+ */
+
+#include "webrtc/p2p/quic/quictransportchannel.h"
+
+#include <utility>
+
+#include "net/quic/crypto/proof_source.h"
+#include "net/quic/crypto/proof_verifier.h"
+#include "net/quic/crypto/quic_crypto_client_config.h"
+#include "net/quic/crypto/quic_crypto_server_config.h"
+#include "net/quic/quic_connection.h"
+#include "net/quic/quic_crypto_client_stream.h"
+#include "net/quic/quic_crypto_server_stream.h"
+#include "net/quic/quic_protocol.h"
+#include "webrtc/base/checks.h"
+#include "webrtc/base/helpers.h"
+#include "webrtc/base/logging.h"
+#include "webrtc/base/socket.h"
+#include "webrtc/base/thread.h"
+#include "webrtc/p2p/base/common.h"
+
+namespace {
+
+// QUIC public header constants for net::QuicConnection. These are arbitrary
+// given that |channel_| only receives packets specific to this channel,
+// in which case we already know the QUIC packets have the correct destination.
+const net::QuicConnectionId kConnectionId = 0;
+const net::IPAddressNumber kConnectionIpAddress(net::kIPv4AddressSize, 0);
+const net::IPEndPoint kConnectionIpEndpoint(kConnectionIpAddress, 0);
+
+// Arbitrary server port number for net::QuicCryptoClientConfig.
+const int kQuicServerPort = 0;
+
+// QUIC connection timeout. This is large so that |channel_| can
+// be responsible for connection timeout.
+const int kIdleConnectionStateLifetime = 1000;  // seconds
+
+// Length of HKDF input keying material, equal to its number of bytes.
+// https://tools.ietf.org/html/rfc5869#section-2.2.
+// TODO(mikescarlett): Verify that input keying material length is correct.
+const size_t kInputKeyingMaterialLength = 32;
+
+// We don't pull the RTP constants from rtputils.h, to avoid a layer violation.
+const size_t kMinRtpPacketLen = 12;
+
+bool IsRtpPacket(const char* data, size_t len) {
+  const uint8_t* u = reinterpret_cast<const uint8_t*>(data);
+  return (len >= kMinRtpPacketLen && (u[0] & 0xC0) == 0x80);
+}
+
+// Function for detecting QUIC packets based off
+// https://tools.ietf.org/html/draft-tsvwg-quic-protocol-02#section-6.
+const size_t kMinQuicPacketLen = 2;
+
+bool IsQuicPacket(const char* data, size_t len) {
+  const uint8_t* u = reinterpret_cast<const uint8_t*>(data);
+  return (len >= kMinQuicPacketLen && (u[0] & 0x80) == 0);
+}
+
+// Used by QuicCryptoServerConfig to provide dummy proof credentials.
+// TODO(mikescarlett): Remove when secure P2P QUIC handshake is possible.
+class DummyProofSource : public net::ProofSource {
+ public:
+  DummyProofSource() {}
+  ~DummyProofSource() override {}
+
+  // ProofSource override.
+  bool GetProof(const net::IPAddressNumber& server_ip,
+                const std::string& hostname,
+                const std::string& server_config,
+                bool ecdsa_ok,
+                const std::vector<std::string>** out_certs,
+                std::string* out_signature,
+                std::string* out_leaf_cert_sct) override {
+    LOG(INFO) << "GetProof() providing dummy credentials for insecure QUIC";
+    std::vector<std::string>* certs = new std::vector<std::string>();
+    certs->push_back("Dummy cert");
+    std::string signature("Dummy signature");
+
+    *out_certs = certs;
+    *out_signature = signature;
+
+    return true;
+  }
+};
+
+// Used by QuicCryptoClientConfig to ignore the peer's credentials
+// and establish an insecure QUIC connection.
+// TODO(mikescarlett): Remove when secure P2P QUIC handshake is possible.
+class InsecureProofVerifier : public net::ProofVerifier {
+ public:
+  InsecureProofVerifier() {}
+  ~InsecureProofVerifier() override {}
+
+  // ProofVerifier override.
+  net::QuicAsyncStatus VerifyProof(
+      const std::string& hostname,
+      const std::string& server_config,
+      const std::vector<std::string>& certs,
+      const std::string& cert_sct,
+      const std::string& signature,
+      const net::ProofVerifyContext* verify_context,
+      std::string* error_details,
+      scoped_ptr<net::ProofVerifyDetails>* verify_details,
+      net::ProofVerifierCallback* callback) override {
+    LOG(INFO) << "VerifyProof() ignoring credentials and returning success";
+    return net::QUIC_SUCCESS;
+  }
+};
+
+}  // namespace
+
+namespace cricket {
+
+QuicTransportChannel::QuicTransportChannel(TransportChannelImpl* channel)
+    : TransportChannelImpl(channel->transport_name(), channel->component()),
+      worker_thread_(rtc::Thread::Current()),
+      channel_(channel),
+      helper_(worker_thread_) {
+  channel_->SignalWritableState.connect(this,
+                                        &QuicTransportChannel::OnWritableState);
+  channel_->SignalReadPacket.connect(this, &QuicTransportChannel::OnReadPacket);
+  channel_->SignalSentPacket.connect(this, &QuicTransportChannel::OnSentPacket);
+  channel_->SignalReadyToSend.connect(this,
+                                      &QuicTransportChannel::OnReadyToSend);
+  channel_->SignalGatheringState.connect(
+      this, &QuicTransportChannel::OnGatheringState);
+  channel_->SignalCandidateGathered.connect(
+      this, &QuicTransportChannel::OnCandidateGathered);
+  channel_->SignalRoleConflict.connect(this,
+                                       &QuicTransportChannel::OnRoleConflict);
+  channel_->SignalRouteChange.connect(this,
+                                      &QuicTransportChannel::OnRouteChange);
+  channel_->SignalConnectionRemoved.connect(
+      this, &QuicTransportChannel::OnConnectionRemoved);
+  channel_->SignalReceivingState.connect(
+      this, &QuicTransportChannel::OnReceivingState);
+
+  // Set the QUIC connection timeout.
+  config_.SetIdleConnectionStateLifetime(
+      net::QuicTime::Delta::FromSeconds(kIdleConnectionStateLifetime),
+      net::QuicTime::Delta::FromSeconds(kIdleConnectionStateLifetime));
+  // Set the bytes reserved for the QUIC connection ID to zero.
+  config_.SetBytesForConnectionIdToSend(0);
+}
+
+QuicTransportChannel::~QuicTransportChannel() {}
+
+bool QuicTransportChannel::SetLocalCertificate(
+    const rtc::scoped_refptr<rtc::RTCCertificate>& certificate) {
+  if (!certificate) {
+    LOG_J(ERROR, this) << "No local certificate was supplied. Not doing QUIC.";
+    return false;
+  }
+  if (!local_certificate_) {
+    local_certificate_ = certificate;
+    return true;
+  }
+  if (certificate == local_certificate_) {
+    // This may happen during renegotiation.
+    LOG_J(INFO, this) << "Ignoring identical certificate";
+    return true;
+  }
+  LOG_J(ERROR, this) << "Local certificate of the QUIC connection already set. "
+                        "Can't change the local certificate once it's active.";
+  return false;
+}
+
+rtc::scoped_refptr<rtc::RTCCertificate>
+QuicTransportChannel::GetLocalCertificate() const {
+  return local_certificate_;
+}
+
+bool QuicTransportChannel::SetSslRole(rtc::SSLRole role) {
+  if (ssl_role_ && *ssl_role_ == role) {
+    LOG_J(WARNING, this) << "Ignoring SSL Role identical to current role.";
+    return true;
+  }
+  if (quic_state_ != QUIC_TRANSPORT_CONNECTED) {
+    ssl_role_ = rtc::Optional<rtc::SSLRole>(role);
+    return true;
+  }
+  LOG_J(ERROR, this)
+      << "SSL Role can't be reversed after the session is setup.";
+  return false;
+}
+
+bool QuicTransportChannel::GetSslRole(rtc::SSLRole* role) const {
+  if (!ssl_role_) {
+    return false;
+  }
+  *role = *ssl_role_;
+  return true;
+}
+
+bool QuicTransportChannel::SetRemoteFingerprint(const std::string& digest_alg,
+                                                const uint8_t* digest,
+                                                size_t digest_len) {
+  if (digest_alg.empty()) {
+    RTC_DCHECK(!digest_len);
+    LOG_J(ERROR, this) << "Remote peer doesn't support digest algorithm.";
+    return false;
+  }
+  std::string remote_fingerprint_value(reinterpret_cast<const char*>(digest),
+                                       digest_len);
+  // Once we have the local certificate, the same remote fingerprint can be set
+  // multiple times. This may happen during renegotiation.
+  if (remote_fingerprint_ &&
+      remote_fingerprint_->value == remote_fingerprint_value &&
+      remote_fingerprint_->algorithm == digest_alg) {
+    LOG_J(INFO, this) << "Ignoring identical remote fingerprint and algorithm";
+    return true;
+  }
+  remote_fingerprint_ = rtc::Optional<RemoteFingerprint>(RemoteFingerprint());
+  remote_fingerprint_->value = remote_fingerprint_value;
+  remote_fingerprint_->algorithm = digest_alg;
+  return true;
+}
+
+bool QuicTransportChannel::ExportKeyingMaterial(const std::string& label,
+                                                const uint8_t* context,
+                                                size_t context_len,
+                                                bool use_context,
+                                                uint8_t* result,
+                                                size_t result_len) {
+  std::string quic_context(reinterpret_cast<const char*>(context), context_len);
+  std::string quic_result;
+  if (!quic_->ExportKeyingMaterial(label, quic_context, result_len,
+                                   &quic_result)) {
+    return false;
+  }
+  quic_result.copy(reinterpret_cast<char*>(result), result_len);
+  return true;
+}
+
+bool QuicTransportChannel::GetSrtpCryptoSuite(int* cipher) {
+  *cipher = rtc::SRTP_AES128_CM_SHA1_80;
+  return true;
+}
+
+// Called from upper layers to send a media packet.
+int QuicTransportChannel::SendPacket(const char* data,
+                                     size_t size,
+                                     const rtc::PacketOptions& options,
+                                     int flags) {
+  if ((flags & PF_SRTP_BYPASS) && IsRtpPacket(data, size)) {
+    return channel_->SendPacket(data, size, options);
+  }
+  LOG(ERROR) << "Failed to send an invalid SRTP bypass packet using QUIC.";
+  return -1;
+}
+
+// The state transition logic here is as follows:
+//     - Before the QUIC handshake is complete, the QUIC channel is unwritable.
+//     - When |channel_| goes writable we start the QUIC handshake.
+//     - Once the QUIC handshake completes, the state is that of the
+//       |channel_| again.
+void QuicTransportChannel::OnWritableState(TransportChannel* channel) {
+  ASSERT(rtc::Thread::Current() == worker_thread_);
+  ASSERT(channel == channel_);
+  LOG_J(VERBOSE, this)
+      << "QuicTransportChannel: channel writable state changed to "
+      << channel_->writable();
+  switch (quic_state_) {
+    case QUIC_TRANSPORT_NEW:
+      // Start the QUIC handshake when |channel_| is writable.
+      // This will fail if the SSL role or remote fingerprint are not set.
+      // Otherwise failure could result from network or QUIC errors.
+      MaybeStartQuic();
+      break;
+    case QUIC_TRANSPORT_CONNECTED:
+      // Note: SignalWritableState fired by set_writable.
+      set_writable(channel_->writable());
+      if (HasDataToWrite()) {
+        OnCanWrite();
+      }
+      break;
+    case QUIC_TRANSPORT_CONNECTING:
+      // This channel is not writable until the QUIC handshake finishes. It
+      // might have been write blocked.
+      if (HasDataToWrite()) {
+        OnCanWrite();
+      }
+      break;
+    case QUIC_TRANSPORT_CLOSED:
+      // TODO(mikescarlett): Allow the QUIC connection to be reset if it drops
+      // due to a non-failure.
+      break;
+  }
+}
+
+void QuicTransportChannel::OnReceivingState(TransportChannel* channel) {
+  ASSERT(rtc::Thread::Current() == worker_thread_);
+  ASSERT(channel == channel_);
+  LOG_J(VERBOSE, this)
+      << "QuicTransportChannel: channel receiving state changed to "
+      << channel_->receiving();
+  if (quic_state_ == QUIC_TRANSPORT_CONNECTED) {
+    // Note: SignalReceivingState fired by set_receiving.
+    set_receiving(channel_->receiving());
+  }
+}
+
+void QuicTransportChannel::OnReadPacket(TransportChannel* channel,
+                                        const char* data,
+                                        size_t size,
+                                        const rtc::PacketTime& packet_time,
+                                        int flags) {
+  ASSERT(rtc::Thread::Current() == worker_thread_);
+  ASSERT(channel == channel_);
+  ASSERT(flags == 0);
+
+  switch (quic_state_) {
+    case QUIC_TRANSPORT_NEW:
+      // This would occur if other peer is ready to start QUIC but this peer
+      // hasn't started QUIC.
+      LOG_J(INFO, this) << "Dropping packet received before QUIC started.";
+      break;
+    case QUIC_TRANSPORT_CONNECTING:
+    case QUIC_TRANSPORT_CONNECTED:
+      // We should only get QUIC or SRTP packets; STUN's already been demuxed.
+      // Is this potentially a QUIC packet?
+      if (IsQuicPacket(data, size)) {
+        if (!HandleQuicPacket(data, size)) {
+          LOG_J(ERROR, this) << "Failed to handle QUIC packet.";
+          return;
+        }
+      } else {
+        // If this is an RTP packet, signal upwards as a bypass packet.
+        if (!IsRtpPacket(data, size)) {
+          LOG_J(ERROR, this) << "Received unexpected non-QUIC, non-RTP packet.";
+          return;
+        }
+        SignalReadPacket(this, data, size, packet_time, PF_SRTP_BYPASS);
+      }
+      break;
+    case QUIC_TRANSPORT_CLOSED:
+      // This shouldn't be happening. Drop the packet.
+      break;
+  }
+}
+
+void QuicTransportChannel::OnSentPacket(TransportChannel* channel,
+                                        const rtc::SentPacket& sent_packet) {
+  ASSERT(rtc::Thread::Current() == worker_thread_);
+  SignalSentPacket(this, sent_packet);
+}
+
+void QuicTransportChannel::OnReadyToSend(TransportChannel* channel) {
+  if (writable()) {
+    SignalReadyToSend(this);
+  }
+}
+
+void QuicTransportChannel::OnGatheringState(TransportChannelImpl* channel) {
+  ASSERT(channel == channel_);
+  SignalGatheringState(this);
+}
+
+void QuicTransportChannel::OnCandidateGathered(TransportChannelImpl* channel,
+                                               const Candidate& c) {
+  ASSERT(channel == channel_);
+  SignalCandidateGathered(this, c);
+}
+
+void QuicTransportChannel::OnRoleConflict(TransportChannelImpl* channel) {
+  ASSERT(channel == channel_);
+  SignalRoleConflict(this);
+}
+
+void QuicTransportChannel::OnRouteChange(TransportChannel* channel,
+                                         const Candidate& candidate) {
+  ASSERT(channel == channel_);
+  SignalRouteChange(this, candidate);
+}
+
+void QuicTransportChannel::OnConnectionRemoved(TransportChannelImpl* channel) {
+  ASSERT(channel == channel_);
+  SignalConnectionRemoved(this);
+}
+
+bool QuicTransportChannel::MaybeStartQuic() {
+  if (!channel_->writable()) {
+    LOG_J(ERROR, this) << "Couldn't start QUIC handshake.";
+    return false;
+  }
+  if (!CreateQuicSession() || !StartQuicHandshake()) {
+    LOG_J(WARNING, this) << "Underlying channel is writable but cannot start "
+                            "the QUIC handshake.";
+    return false;
+  }
+  // Verify connection is not closed due to QUIC bug or network failure.
+  // A closed connection should not happen since |channel_| is writable.
+  if (!quic_->connection()->connected()) {
+    LOG_J(ERROR, this) << "QUIC connection should not be closed if underlying "
+                          "channel is writable.";
+    return false;
+  }
+  // Indicate that |quic_| is ready to receive QUIC packets.
+  set_quic_state(QUIC_TRANSPORT_CONNECTING);
+  return true;
+}
+
+bool QuicTransportChannel::CreateQuicSession() {
+  if (!ssl_role_ || !remote_fingerprint_) {
+    return false;
+  }
+  net::Perspective perspective = (*ssl_role_ == rtc::SSL_CLIENT)
+                                     ? net::Perspective::IS_CLIENT
+                                     : net::Perspective::IS_SERVER;
+  bool owns_writer = false;
+  scoped_ptr<net::QuicConnection> connection(new net::QuicConnection(
+      kConnectionId, kConnectionIpEndpoint, &helper_, this, owns_writer,
+      perspective, net::QuicSupportedVersions()));
+  quic_.reset(new QuicSession(std::move(connection), config_));
+  quic_->SignalHandshakeComplete.connect(
+      this, &QuicTransportChannel::OnHandshakeComplete);
+  quic_->SignalConnectionClosed.connect(
+      this, &QuicTransportChannel::OnConnectionClosed);
+  return true;
+}
+
+bool QuicTransportChannel::StartQuicHandshake() {
+  if (*ssl_role_ == rtc::SSL_CLIENT) {
+    // Unique identifier for remote peer.
+    net::QuicServerId server_id(remote_fingerprint_->value, kQuicServerPort);
+    // Perform authentication of remote peer; owned by QuicCryptoClientConfig.
+    // TODO(mikescarlett): Actually verify proof.
+    net::ProofVerifier* proof_verifier = new InsecureProofVerifier();
+    quic_crypto_client_config_.reset(
+        new net::QuicCryptoClientConfig(proof_verifier));
+    net::QuicCryptoClientStream* crypto_stream =
+        new net::QuicCryptoClientStream(server_id, quic_.get(),
+                                        new net::ProofVerifyContext(),
+                                        quic_crypto_client_config_.get(), this);
+    quic_->StartClientHandshake(crypto_stream);
+    LOG_J(INFO, this) << "QuicTransportChannel: Started client handshake.";
+  } else {
+    RTC_DCHECK_EQ(*ssl_role_, rtc::SSL_SERVER);
+    // Provide credentials to remote peer; owned by QuicCryptoServerConfig.
+    // TODO(mikescarlett): Actually provide credentials.
+    net::ProofSource* proof_source = new DummyProofSource();
+    // Input keying material to HKDF, per http://tools.ietf.org/html/rfc5869.
+    // This is pseudorandom so that HKDF-Extract outputs a pseudorandom key,
+    // since QuicCryptoServerConfig does not use a salt value.
+    std::string source_address_token_secret;
+    if (!rtc::CreateRandomString(kInputKeyingMaterialLength,
+                                 &source_address_token_secret)) {
+      LOG_J(ERROR, this) << "Error generating input keying material for HKDF.";
+      return false;
+    }
+    quic_crypto_server_config_.reset(new net::QuicCryptoServerConfig(
+        source_address_token_secret, helper_.GetRandomGenerator(),
+        proof_source));
+    // Provide server with serialized config string to prove ownership.
+    net::QuicCryptoServerConfig::ConfigOptions options;
+    quic_crypto_server_config_->AddDefaultConfig(helper_.GetRandomGenerator(),
+                                                 helper_.GetClock(), options);
+    net::QuicCryptoServerStream* crypto_stream =
+        new net::QuicCryptoServerStream(quic_crypto_server_config_.get(),
+                                        quic_.get());
+    quic_->StartServerHandshake(crypto_stream);
+    LOG_J(INFO, this) << "QuicTransportChannel: Started server handshake.";
+  }
+  return true;
+}
+
+bool QuicTransportChannel::HandleQuicPacket(const char* data, size_t size) {
+  ASSERT(rtc::Thread::Current() == worker_thread_);
+  return quic_->OnReadPacket(data, size);
+}
+
+net::WriteResult QuicTransportChannel::WritePacket(
+    const char* buffer,
+    size_t buf_len,
+    const net::IPAddressNumber& self_address,
+    const net::IPEndPoint& peer_address) {
+  // QUIC should never call this if IsWriteBlocked, but just in case...
+  if (IsWriteBlocked()) {
+    return net::WriteResult(net::WRITE_STATUS_BLOCKED, EWOULDBLOCK);
+  }
+  // TODO(mikescarlett): Figure out how to tell QUIC "I dropped your packet, but
+  // don't block" without the QUIC connection tearing itself down.
+  int sent = channel_->SendPacket(buffer, buf_len, rtc::PacketOptions());
+  int bytes_written = sent > 0 ? sent : 0;
+  return net::WriteResult(net::WRITE_STATUS_OK, bytes_written);
+}
+
+// TODO(mikescarlett): Implement check for whether |channel_| is currently
+// write blocked so that |quic_| does not try to write packet. This is
+// necessary because |channel_| can be writable yet write blocked and
+// channel_->GetError() is not flushed when there is no error.
+bool QuicTransportChannel::IsWriteBlocked() const {
+  return !channel_->writable();
+}
+
+void QuicTransportChannel::OnHandshakeComplete() {
+  set_quic_state(QUIC_TRANSPORT_CONNECTED);
+  set_writable(true);
+  // OnReceivingState might have been called before the QUIC channel was
+  // connected, in which case the QUIC channel is now receiving.
+  if (channel_->receiving()) {
+    set_receiving(true);
+  }
+}
+
+void QuicTransportChannel::OnConnectionClosed(net::QuicErrorCode error,
+                                              bool from_peer) {
+  LOG_J(INFO, this) << "Connection closed by " << (from_peer ? "other" : "this")
+                    << " peer "
+                    << "with QUIC error " << error;
+  // TODO(mikescarlett): Allow the QUIC session to be reset when the connection
+  // does not close due to failure.
+  set_quic_state(QUIC_TRANSPORT_CLOSED);
+  set_writable(false);
+}
+
+void QuicTransportChannel::OnProofValid(
+    const net::QuicCryptoClientConfig::CachedState& cached) {
+  LOG_J(INFO, this) << "Cached proof marked valid";
+}
+
+void QuicTransportChannel::OnProofVerifyDetailsAvailable(
+    const net::ProofVerifyDetails& verify_details) {
+  LOG_J(INFO, this) << "Proof verify details available from"
+                    << " QuicCryptoClientStream";
+}
+
+bool QuicTransportChannel::HasDataToWrite() const {
+  return quic_ && quic_->HasDataToWrite();
+}
+
+void QuicTransportChannel::OnCanWrite() {
+  RTC_DCHECK(quic_ != nullptr);
+  quic_->connection()->OnCanWrite();
+}
+
+void QuicTransportChannel::set_quic_state(QuicTransportState state) {
+  LOG_J(VERBOSE, this) << "set_quic_state from:" << quic_state_ << " to "
+                       << state;
+  quic_state_ = state;
+}
+
+}  // namespace cricket