/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=4 sw=2 et cindent: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "HttpLog.h"
#include "Http3Session.h"
#include "Http3Stream.h"
#include "mozilla/net/DNS.h"
#include "nsHttpHandler.h"
#include "mozilla/RefPtr.h"
#include "mozilla/Telemetry.h"
#include "ASpdySession.h"  // because of SoftStreamError()
#include "nsIOService.h"
#include "nsISSLSocketControl.h"
#include "ScopedNSSTypes.h"
#include "nsQueryObject.h"
#include "nsSocketTransportService2.h"
#include "nsThreadUtils.h"
#include "QuicSocketControl.h"
#include "SSLServerCertVerification.h"
#include "SSLTokensCache.h"
#include "HttpConnectionUDP.h"
#include "sslerr.h"

namespace mozilla {
namespace net {

const uint64_t HTTP3_APP_ERROR_NO_ERROR = 0x100;
const uint64_t HTTP3_APP_ERROR_GENERAL_PROTOCOL_ERROR = 0x101;
const uint64_t HTTP3_APP_ERROR_INTERNAL_ERROR = 0x102;
const uint64_t HTTP3_APP_ERROR_STREAM_CREATION_ERROR = 0x103;
const uint64_t HTTP3_APP_ERROR_CLOSED_CRITICAL_STREAM = 0x104;
const uint64_t HTTP3_APP_ERROR_FRAME_UNEXPECTED = 0x105;
const uint64_t HTTP3_APP_ERROR_FRAME_ERROR = 0x106;
const uint64_t HTTP3_APP_ERROR_EXCESSIVE_LOAD = 0x107;
const uint64_t HTTP3_APP_ERROR_ID_ERROR = 0x108;
const uint64_t HTTP3_APP_ERROR_SETTINGS_ERROR = 0x109;
const uint64_t HTTP3_APP_ERROR_MISSING_SETTINGS = 0x10a;
const uint64_t HTTP3_APP_ERROR_REQUEST_REJECTED = 0x10b;
const uint64_t HTTP3_APP_ERROR_REQUEST_CANCELLED = 0x10c;
const uint64_t HTTP3_APP_ERROR_REQUEST_INCOMPLETE = 0x10d;
const uint64_t HTTP3_APP_ERROR_EARLY_RESPONSE = 0x10e;
const uint64_t HTTP3_APP_ERROR_CONNECT_ERROR = 0x10f;
const uint64_t HTTP3_APP_ERROR_VERSION_FALLBACK = 0x110;

const uint32_t UDP_MAX_PACKET_SIZE = 4096;
const uint32_t MAX_PTO_COUNTS = 16;

NS_IMPL_ADDREF(Http3Session)
NS_IMPL_RELEASE(Http3Session)
NS_INTERFACE_MAP_BEGIN(Http3Session)
  NS_INTERFACE_MAP_ENTRY(nsAHttpConnection)
  NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
  NS_INTERFACE_MAP_ENTRY_CONCRETE(Http3Session)
NS_INTERFACE_MAP_END

Http3Session::Http3Session()
    : mState(INITIALIZING),
      mAuthenticationStarted(false),
      mCleanShutdown(false),
      mGoawayReceived(false),
      mShouldClose(false),
      mIsClosedByNeqo(false),
      mError(NS_OK),
      mSocketError(NS_OK),
      mBeforeConnectedError(false),
      mTimerActive(false) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  LOG(("Http3Session::Http3Session [this=%p]", this));

  mCurrentForegroundTabOuterContentWindowId =
      gHttpHandler->ConnMgr()->CurrentTopLevelOuterContentWindowId();
}

nsresult Http3Session::Init(const nsHttpConnectionInfo* aConnInfo,
                            nsISocketTransport* aSocketTransport,
                            HttpConnectionUDP* readerWriter) {
  LOG3(("Http3Session::Init %p", this));

  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  MOZ_ASSERT(aSocketTransport);
  MOZ_ASSERT(readerWriter);

  mConnInfo = aConnInfo->Clone();
  mSocketTransport = aSocketTransport;

  nsCOMPtr<nsISupports> info;
  Unused << mSocketTransport->GetSecurityInfo(getter_AddRefs(info));
  mSocketControl = do_QueryObject(info);

  // Get the local and remote address neqo needs it.
  NetAddr selfAddr;
  if (NS_FAILED(mSocketTransport->GetSelfAddr(&selfAddr))) {
    LOG3(("Http3Session::Init GetSelfAddr failed [this=%p]", this));
    return NS_ERROR_FAILURE;
  }
  char buf[kIPv6CStrBufSize];
  selfAddr.ToStringBuffer(buf, kIPv6CStrBufSize);

  nsAutoCString selfAddrStr;
  if (selfAddr.raw.family == AF_INET6) {
    selfAddrStr.Append("[");
  }
  // Append terminating ']' and port.
  selfAddrStr.Append(buf, strlen(buf));
  if (selfAddr.raw.family == AF_INET6) {
    selfAddrStr.Append("]:");
    selfAddrStr.AppendInt(ntohs(selfAddr.inet6.port));
  } else {
    selfAddrStr.Append(":");
    selfAddrStr.AppendInt(ntohs(selfAddr.inet.port));
  }

  NetAddr peerAddr;
  if (NS_FAILED(mSocketTransport->GetPeerAddr(&peerAddr))) {
    LOG3(("Http3Session::Init GetPeerAddr failed [this=%p]", this));
    return NS_ERROR_FAILURE;
  }
  peerAddr.ToStringBuffer(buf, kIPv6CStrBufSize);

  nsAutoCString peerAddrStr;
  if (peerAddr.raw.family == AF_INET6) {
    peerAddrStr.Append("[");
  }
  peerAddrStr.Append(buf, strlen(buf));
  // Append terminating ']' and port.
  if (peerAddr.raw.family == AF_INET6) {
    peerAddrStr.Append("]:");
    peerAddrStr.AppendInt(ntohs(peerAddr.inet6.port));
  } else {
    peerAddrStr.Append(':');
    peerAddrStr.AppendInt(ntohs(peerAddr.inet.port));
  }

  LOG3(
      ("Http3Session::Init origin=%s, alpn=%s, selfAddr=%s, peerAddr=%s,"
       " qpack table size=%u, max blocked streams=%u [this=%p]",
       PromiseFlatCString(mConnInfo->GetOrigin()).get(),
       PromiseFlatCString(mConnInfo->GetNPNToken()).get(), selfAddrStr.get(),
       peerAddrStr.get(), gHttpHandler->DefaultQpackTableSize(),
       gHttpHandler->DefaultHttp3MaxBlockedStreams(), this));

  nsresult rv = NeqoHttp3Conn::Init(
      mConnInfo->GetOrigin(), mConnInfo->GetNPNToken(), selfAddrStr,
      peerAddrStr, gHttpHandler->DefaultQpackTableSize(),
      gHttpHandler->DefaultHttp3MaxBlockedStreams(),
      gHttpHandler->Http3QlogDir(), getter_AddRefs(mHttp3Connection));
  if (NS_FAILED(rv)) {
    return rv;
  }

  nsAutoCString peerId;
  mSocketControl->GetPeerId(peerId);
  nsTArray<uint8_t> token;
  if (NS_SUCCEEDED(SSLTokensCache::Get(peerId, token))) {
    LOG(("Found a resumption token in the cache."));
    mHttp3Connection->SetResumptionToken(token);
    if (mHttp3Connection->IsZeroRtt()) {
      LOG(("Can send ZeroRtt data"));
      RefPtr<Http3Session> self(this);
      mState = ZERORTT;
      // Let the nsHttpConnectionMgr know that the connection can accept
      // transactions.
      // We need to dispatch the following function to this thread so that
      // it is executed after the current function. At this point a
      // Http3Session is still being initialized and ReportHttp3Connection
      // will try to dispatch transaction on this session therefore it
      // needs to be executed after the initializationg is done.
      DebugOnly<nsresult> rv = NS_DispatchToCurrentThread(
          NS_NewRunnableFunction("Http3Session::ReportHttp3Connection",
                                 [self]() { self->ReportHttp3Connection(); }));
      NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
                           "NS_DispatchToCurrentThread failed");
    }
  }

  // After this line, Http3Session and HttpConnectionUDP become a cycle. We put
  // this line in the end of Http3Session::Init to make sure Http3Session can be
  // released when Http3Session::Init early returned.
  mSegmentReaderWriter = readerWriter;
  return NS_OK;
}

// Shutdown the http3session and close all transactions.
void Http3Session::Shutdown() {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");

  if ((mBeforeConnectedError ||
       (mError == NS_ERROR_NET_HTTP3_PROTOCOL_ERROR)) &&
      (mError !=
       mozilla::psm::GetXPCOMFromNSSError(SSL_ERROR_BAD_CERT_DOMAIN))) {
    gHttpHandler->ExcludeHttp3(mConnInfo);
  }

  for (auto iter = mStreamTransactionHash.Iter(); !iter.Done(); iter.Next()) {
    RefPtr<Http3Stream> stream = iter.Data();

    if (mBeforeConnectedError) {
      // We have an error before we were connected, just restart transactions.
      // The transaction restart code path will remove AltSvc mapping and the
      // direct path will be used.
      MOZ_ASSERT(NS_FAILED(mError));
      stream->Close(NS_ERROR_NET_RESET);
    } else if (!stream->HasStreamId()) {
      if (NS_SUCCEEDED(mError)) {
        // Connection has not been started yet. We can restart it.
        stream->Transaction()->DoNotRemoveAltSvc();
      }
      stream->Close(NS_ERROR_NET_RESET);
    } else if (stream->RecvdData()) {
      stream->Close(NS_ERROR_NET_PARTIAL_TRANSFER);
    } else if (mError == NS_ERROR_NET_HTTP3_PROTOCOL_ERROR) {
      stream->Close(NS_ERROR_NET_HTTP3_PROTOCOL_ERROR);
    } else {
      stream->Close(NS_ERROR_ABORT);
    }
    RemoveStreamFromQueues(stream);
    if (stream->HasStreamId()) {
      mStreamIdHash.Remove(stream->StreamId());
    }
  }

  mStreamTransactionHash.Clear();
}

Http3Session::~Http3Session() {
  LOG3(("Http3Session::~Http3Session %p", this));

  Telemetry::Accumulate(Telemetry::HTTP3_REQUEST_PER_CONN, mTransactionCount);
  Telemetry::Accumulate(Telemetry::HTTP3_BLOCKED_BY_STREAM_LIMIT_PER_CONN,
                        mBlockedByStreamLimitCount);
  Telemetry::Accumulate(Telemetry::HTTP3_TRANS_BLOCKED_BY_STREAM_LIMIT_PER_CONN,
                        mTransactionsBlockedByStreamLimitCount);

  Telemetry::Accumulate(
      Telemetry::HTTP3_TRANS_SENDING_BLOCKED_BY_FLOW_CONTROL_PER_CONN,
      mTransactionsSenderBlockedByFlowControlCount);

  Shutdown();
}

// This function may return a socket error.
// It will not return an error if socket error is
// NS_BASE_STREAM_WOULD_BLOCK.
// A caller of this function will close the Http3 connection
// in case of a error.
// The only callers is:
//   HttpConnectionUDP::OnInputStreamReady ->
//   HttpConnectionUDP::OnSocketReadable ->
//   Http3Session::WriteSegmentsAgain
nsresult Http3Session::ProcessInput(uint32_t* aCountRead) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  MOZ_ASSERT(mSegmentReaderWriter);

  LOG(("Http3Session::ProcessInput writer=%p [this=%p state=%d]",
       mSegmentReaderWriter.get(), this, mState));

  uint8_t packet[UDP_MAX_PACKET_SIZE];
  nsresult rv = NS_OK;
  // Read from socket until NS_BASE_STREAM_WOULD_BLOCK or another error.
  do {
    uint32_t read = 0;
    rv = mSegmentReaderWriter->OnWriteSegment((char*)packet,
                                              UDP_MAX_PACKET_SIZE, &read);
    if (NS_SUCCEEDED(rv)) {
      mHttp3Connection->ProcessInput(packet, read);
      *aCountRead += read;
    }
  } while (NS_SUCCEEDED(rv));
  // NS_BASE_STREAM_WOULD_BLOCK means that there is no more date to read.
  if (rv == NS_BASE_STREAM_WOULD_BLOCK) {
    return NS_OK;
  }

  LOG(("Http3Session::ProcessInput error=%" PRIx32 " [this=%p]",
       static_cast<uint32_t>(rv), this));
  if (NS_SUCCEEDED(mSocketError)) {
    mSocketError = rv;
  }
  return rv;
}

nsresult Http3Session::ProcessTransactionRead(uint64_t stream_id,
                                              uint32_t count,
                                              uint32_t* countWritten) {
  RefPtr<Http3Stream> stream = mStreamIdHash.Get(stream_id);
  if (!stream) {
    LOG(
        ("Http3Session::ProcessTransactionRead - stream not found "
         "stream_id=0x%" PRIx64 " [this=%p].",
         stream_id, this));
    return NS_OK;
  }

  return ProcessTransactionRead(stream, count, countWritten);
}

nsresult Http3Session::ProcessTransactionRead(Http3Stream* stream,
                                              uint32_t count,
                                              uint32_t* countWritten) {
  nsresult rv = stream->WriteSegments(stream, count, countWritten);

  if (ASpdySession::SoftStreamError(rv) || stream->Done()) {
    LOG3(
        ("Http3Session::ProcessSingleTransactionRead session=%p stream=%p "
         "0x%" PRIx64 " cleanup stream rv=0x%" PRIx32 " done=%d.\n",
         this, stream, stream->StreamId(), static_cast<uint32_t>(rv),
         stream->Done()));
    CloseStream(stream,
                (rv == NS_BINDING_RETARGETED) ? NS_BINDING_RETARGETED : NS_OK);
    return NS_OK;
  }

  if (NS_FAILED(rv) && rv != NS_BASE_STREAM_WOULD_BLOCK) {
    return rv;
  }
  return NS_OK;
}

nsresult Http3Session::ProcessEvents(uint32_t count) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");

  LOG(("Http3Session::ProcessEvents [this=%p]", this));

  // We need an array to pick up header data or a resumption token.
  nsTArray<uint8_t> data;
  Http3Event event;
  event.tag = Http3Event::Tag::NoEvent;

  nsresult rv = mHttp3Connection->GetEvent(&event, data);
  if (NS_FAILED(rv)) {
    LOG(("Http3Session::ProcessEvents [this=%p] rv=%" PRIx32, this,
         static_cast<uint32_t>(rv)));
    return rv;
  }

  while (event.tag != Http3Event::Tag::NoEvent) {
    switch (event.tag) {
      case Http3Event::Tag::HeaderReady: {
        MOZ_ASSERT(mState == CONNECTED);
        LOG(("Http3Session::ProcessEvents - HeaderReady"));
        uint64_t id = event.header_ready.stream_id;

        RefPtr<Http3Stream> stream = mStreamIdHash.Get(id);
        if (!stream) {
          LOG(
              ("Http3Session::ProcessEvents - HeaderReady - stream not found "
               "stream_id=0x%" PRIx64 " [this=%p].",
               id, this));
          continue;
        }

        stream->SetResponseHeaders(data, event.header_ready.fin);

        uint32_t read = 0;
        rv = ProcessTransactionRead(stream, count, &read);

        if (NS_FAILED(rv)) {
          LOG(("Http3Session::ProcessEvents [this=%p] rv=%" PRIx32, this,
               static_cast<uint32_t>(rv)));
          return rv;
        }
        break;
      }
      case Http3Event::Tag::DataReadable: {
        MOZ_ASSERT(mState == CONNECTED);
        LOG(("Http3Session::ProcessEvents - DataReadable"));
        uint64_t id = event.data_readable.stream_id;

        uint32_t read = 0;
        nsresult rv = ProcessTransactionRead(id, count, &read);

        if (NS_FAILED(rv)) {
          LOG(("Http3Session::ProcessEvents [this=%p] rv=%" PRIx32, this,
               static_cast<uint32_t>(rv)));
          return rv;
        }
        break;
      }
      case Http3Event::Tag::DataWritable: {
        MOZ_ASSERT(CanSandData());
        LOG(("Http3Session::ProcessEvents - DataWritable"));

        RefPtr<Http3Stream> stream =
            mStreamIdHash.Get(event.data_writable.stream_id);
        if (stream) {
          StreamReadyToWrite(stream);
        }
      } break;
      case Http3Event::Tag::Reset:
        LOG(("Http3Session::ProcessEvents - Reset"));
        ResetRecvd(event.reset.stream_id, event.reset.error);
        break;
      case Http3Event::Tag::StopSending:
        LOG(("Http3Session::ProcessEvents - StopSeniding with error 0x%" PRIx64,
             event.stop_sending.error));
        if (event.stop_sending.error == HTTP3_APP_ERROR_NO_ERROR) {
          RefPtr<Http3Stream> stream =
              mStreamIdHash.Get(event.data_writable.stream_id);
          if (stream) {
            stream->StopSending();
          }
        } else {
          ResetRecvd(event.reset.stream_id, event.reset.error);
        }
        break;
      case Http3Event::Tag::PushPromise:
        LOG(("Http3Session::ProcessEvents - PushPromise"));
        break;
      case Http3Event::Tag::PushHeaderReady:
        LOG(("Http3Session::ProcessEvents - PushHeaderReady"));
        break;
      case Http3Event::Tag::PushDataReadable:
        LOG(("Http3Session::ProcessEvents - PushDataReadable"));
        break;
      case Http3Event::Tag::PushCanceled:
        LOG(("Http3Session::ProcessEvents - PushCanceled"));
        break;
      case Http3Event::Tag::RequestsCreatable:
        LOG(("Http3Session::ProcessEvents - StreamCreatable"));
        ProcessPending();
        break;
      case Http3Event::Tag::AuthenticationNeeded:
        LOG(("Http3Session::ProcessEvents - AuthenticationNeeded %d",
             mAuthenticationStarted));
        if (!mAuthenticationStarted) {
          mAuthenticationStarted = true;
          LOG(("Http3Session::ProcessEvents - AuthenticationNeeded called"));
          CallCertVerification();
        }
        break;
      case Http3Event::Tag::ZeroRttRejected:
        LOG(("Http3Session::ProcessEvents - ZeroRttRejected"));
        if (mState == ZERORTT) {
          mState = INITIALIZING;
          Finish0Rtt(true);
        }
        break;
      case Http3Event::Tag::ResumptionToken: {
        LOG(("Http3Session::ProcessEvents - ResumptionToken"));
        if (!data.IsEmpty()) {
          LOG(("Got a resumption token"));
          nsAutoCString peerId;
          mSocketControl->GetPeerId(peerId);
          if (NS_FAILED(SSLTokensCache::Put(
                  peerId, data.Elements(), data.Length(), mSocketControl,
                  PR_Now() + event.resumption_token.expire_in))) {
            LOG(("Adding resumption token failed"));
          }
        }
      } break;
      case Http3Event::Tag::ConnectionConnected: {
        LOG(("Http3Session::ProcessEvents - ConnectionConnected"));
        bool was0RTT = mState == ZERORTT;
        mState = CONNECTED;
        SetSecInfo();
        mSocketControl->HandshakeCompleted();
        if (was0RTT) {
          Finish0Rtt(false);
        }

        OnTransportStatus(mSocketTransport, NS_NET_STATUS_CONNECTED_TO, 0);
        // Also send the NS_NET_STATUS_TLS_HANDSHAKE_ENDED event.
        OnTransportStatus(mSocketTransport, NS_NET_STATUS_TLS_HANDSHAKE_ENDED,
                          0);

        ReportHttp3Connection();
      } break;
      case Http3Event::Tag::GoawayReceived:
        LOG(("Http3Session::ProcessEvents - GoawayReceived"));
        mGoawayReceived = true;
        break;
      case Http3Event::Tag::ConnectionClosing:
        LOG(("Http3Session::ProcessEvents - ConnectionClosing"));
        if (NS_SUCCEEDED(mError) && !IsClosing()) {
          mError = NS_ERROR_NET_HTTP3_PROTOCOL_ERROR;
          CloseConnectionTelemetry(event.connection_closing.error, true);
        }
        return mError;
        break;
      case Http3Event::Tag::ConnectionClosed:
        LOG(("Http3Session::ProcessEvents - ConnectionClosed"));
        if (NS_SUCCEEDED(mError)) {
          mError = NS_ERROR_NET_TIMEOUT;
          CloseConnectionTelemetry(event.connection_closed.error, false);
        }
        mIsClosedByNeqo = true;
        LOG(("Http3Session::ProcessEvents - ConnectionClosed error=%" PRIx32,
             static_cast<uint32_t>(mError)));
        // We need to return here and let HttpConnectionUDP close the session.
        return mError;
        break;
      default:
        break;
    }
    // Delete previous content of data
    data.TruncateLength(0);
    rv = mHttp3Connection->GetEvent(&event, data);
    if (NS_FAILED(rv)) {
      LOG(("Http3Session::ProcessEvents [this=%p] rv=%" PRIx32, this,
           static_cast<uint32_t>(rv)));
      return rv;
    }
  }

  return NS_OK;
}  // namespace net

// This function may return a socket error.
// It will not return an error if socket error is
// NS_BASE_STREAM_WOULD_BLOCK.
// A Caller of this function will close the Http3 connection
// if this function returns an error.
// Callers are:
//   1) HttpConnectionUDP::OnQuicTimeoutExpired
//   2) HttpConnectionUDP::OnOutputStreamReady ->
//      HttpConnectionUDP::OnSocketWritable ->
//      Http3Session::ReadSegmentsAgain
nsresult Http3Session::ProcessOutput() {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  MOZ_ASSERT(mSegmentReaderWriter);

  LOG(("Http3Session::ProcessOutput reader=%p, [this=%p]",
       mSegmentReaderWriter.get(), this));

  // Process neqo.
  uint64_t timeout = mHttp3Connection->ProcessOutput();

  // Check if we have a packet that could not have been sent in a previous
  // iteration or maybe get new packets to send.
  while (mPacketToSend.Length() ||
         NS_SUCCEEDED(mHttp3Connection->GetDataToSend(mPacketToSend))) {
    MOZ_ASSERT(mPacketToSend.Length());
    LOG(("Http3Session::ProcessOutput sending packet with %u bytes [this=%p].",
         (uint32_t)mPacketToSend.Length(), this));
    uint32_t written = 0;
    nsresult rv = mSegmentReaderWriter->OnReadSegment(
        (const char*)mPacketToSend.Elements(), mPacketToSend.Length(),
        &written);
    if (rv == NS_BASE_STREAM_WOULD_BLOCK) {
      // The socket is blocked, keep the packet and we will send it when the
      // socket is ready to send data again.
      if (mConnection) {
        Unused << mConnection->ResumeSend();
      }
      SetupTimer(timeout);
      return NS_OK;
    }
    if (NS_FAILED(rv)) {
      mSocketError = rv;
      // Ok the socket is blocked or there is an error, return from here,
      // we do not need to set a timer if error is not
      // NS_BASE_STREAM_WOULD_BLOCK, i.e. we are closing the connection.
      return rv;
    }
    MOZ_ASSERT(written == mPacketToSend.Length());
    mPacketToSend.TruncateLength(0);
  }

  SetupTimer(timeout);
  return NS_OK;
}

// This is only called when timer expires.
// It is called by HttpConnectionUDP::OnQuicTimeout.
// If tihs function returns an error OnQuicTimeout will handle the error
// properly and close the connection.
nsresult Http3Session::ProcessOutputAndEvents() {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  // ProcessOutput could fire another timer. Need to unset the flag before that.
  mTimerActive = false;

  MOZ_ASSERT(mTimerShouldTrigger);

  Telemetry::AccumulateTimeDelta(Telemetry::HTTP3_TIMER_DELAYED,
                                 mTimerShouldTrigger, TimeStamp::Now());

  mTimerShouldTrigger = TimeStamp();

  nsresult rv = ProcessOutput();
  if (NS_FAILED(rv)) {
    return rv;
  }
  return ProcessEvents(nsIOService::gDefaultSegmentSize);
}

void Http3Session::SetupTimer(uint64_t aTimeout) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  // UINT64_MAX indicated a no-op from neqo, which only happens when a
  // connection is in or going to be Closed state.
  if (aTimeout == UINT64_MAX) {
    return;
  }

  LOG(("Http3Session::SetupTimer to %" PRIu64 "ms [this=%p].", aTimeout, this));

  // Remember the time when the timer should trigger.
  mTimerShouldTrigger =
      TimeStamp::Now() + TimeDuration::FromMilliseconds(aTimeout);

  if (mTimerActive && mTimer) {
    LOG(
        ("  -- Previous timer has not fired. Update the delay instead of "
         "re-initializing the timer"));
    mTimer->SetDelay(aTimeout);
    return;
  }

  if (!mTimer) {
    mTimer = NS_NewTimer();
  }

  mTimerActive = true;

  if (!mTimer ||
      NS_FAILED(mTimer->InitWithNamedFuncCallback(
          &HttpConnectionUDP::OnQuicTimeout, mSegmentReaderWriter, aTimeout,
          nsITimer::TYPE_ONE_SHOT, "net::HttpConnectionUDP::OnQuicTimeout"))) {
    NS_DispatchToCurrentThread(NewRunnableMethod(
        "net::HttpConnectionUDP::OnQuicTimeoutExpired", mSegmentReaderWriter,
        &HttpConnectionUDP::OnQuicTimeoutExpired));
  }
}

bool Http3Session::AddStream(nsAHttpTransaction* aHttpTransaction,
                             int32_t aPriority,
                             nsIInterfaceRequestor* aCallbacks) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");

  nsHttpTransaction* trans = aHttpTransaction->QueryHttpTransaction();

  if (!mConnection) {
    // Get the connection from the first transaction.
    mConnection = aHttpTransaction->Connection();
  }

  if (IsClosing()) {
    LOG3(
        ("Http3Session::AddStream %p atrans=%p trans=%p session unusable - "
         "resched.\n",
         this, aHttpTransaction, trans));
    aHttpTransaction->SetConnection(nullptr);
    nsresult rv = gHttpHandler->InitiateTransaction(trans, trans->Priority());
    if (NS_FAILED(rv)) {
      LOG3(
          ("Http3Session::AddStream %p atrans=%p trans=%p failed to initiate "
           "transaction (0x%" PRIx32 ").\n",
           this, aHttpTransaction, trans, static_cast<uint32_t>(rv)));
    }
    return true;
  }

  aHttpTransaction->SetConnection(this);
  aHttpTransaction->OnActivated();

  LOG3(("Http3Session::AddStream %p atrans=%p.\n", this, aHttpTransaction));
  Http3Stream* stream = new Http3Stream(aHttpTransaction, this);
  mStreamTransactionHash.Put(aHttpTransaction, RefPtr{stream});

  if (mState == ZERORTT) {
    if (!stream->Do0RTT()) {
      LOG(("Http3Session %p will not get early data from Http3Stream %p", this,
           stream));
      if (!mCannotDo0RTTStreams.Contains(stream)) {
        mCannotDo0RTTStreams.AppendElement(stream);
      }
      return true;
    } else {
      m0RTTStreams.AppendElement(stream);
    }
  }

  if (!mFirstHttpTransaction && !IsConnected()) {
    mFirstHttpTransaction = aHttpTransaction->QueryHttpTransaction();
    LOG3(("Http3Session::AddStream first session=%p trans=%p ", this,
          mFirstHttpTransaction.get()));
  }

  StreamReadyToWrite(stream);

  return true;
}

bool Http3Session::CanReuse() {
  return CanSandData() && !(mGoawayReceived || mShouldClose);
}

void Http3Session::QueueStream(Http3Stream* stream) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  MOZ_ASSERT(!stream->Queued());

  LOG3(("Http3Session::QueueStream %p stream %p queued.", this, stream));

  stream->SetQueued(true);
  mQueuedStreams.Push(stream);
}

void Http3Session::ProcessPending() {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");

  Http3Stream* stream;
  while ((stream = mQueuedStreams.PopFront())) {
    LOG3(("Http3Session::ProcessPending %p stream %p woken from queue.", this,
          stream));
    MOZ_ASSERT(stream->Queued());
    stream->SetQueued(false);
    mReadyForWrite.Push(stream);
  }
  MaybeResumeSend();
}

static void RemoveStreamFromQueue(Http3Stream* aStream,
                                  nsDeque<Http3Stream>& queue) {
  size_t size = queue.GetSize();
  for (size_t count = 0; count < size; ++count) {
    Http3Stream* stream = queue.PopFront();
    if (stream != aStream) {
      queue.Push(stream);
    }
  }
}

void Http3Session::RemoveStreamFromQueues(Http3Stream* aStream) {
  RemoveStreamFromQueue(aStream, mReadyForWrite);
  RemoveStreamFromQueue(aStream, mQueuedStreams);
  mSlowConsumersReadyForRead.RemoveElement(aStream);
}

// This is called by Http3Stream::OnReadSegment.
// ProcessOutput will be called in Http3Session::ReadSegment that
// calls Http3Stream::OnReadSegment.
nsresult Http3Session::TryActivating(
    const nsACString& aMethod, const nsACString& aScheme,
    const nsACString& aAuthorityHeader, const nsACString& aPath,
    const nsACString& aHeaders, uint64_t* aStreamId, Http3Stream* aStream) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  MOZ_ASSERT(*aStreamId == UINT64_MAX);

  LOG(("Http3Session::TryActivating [stream=%p, this=%p state=%d]", aStream,
       this, mState));

  if (IsClosing()) {
    if (NS_FAILED(mError)) {
      return mError;
    }
    return NS_ERROR_FAILURE;
  }

  if (aStream->Queued()) {
    LOG3(("Http3Session::TryActivating %p stream=%p already queued.\n", this,
          aStream));
    return NS_BASE_STREAM_WOULD_BLOCK;
  }

  if (mState == ZERORTT) {
    if (!aStream->Do0RTT()) {
      MOZ_ASSERT(!mCannotDo0RTTStreams.Contains(aStream));
      return NS_BASE_STREAM_WOULD_BLOCK;
    }
  }

  nsresult rv = mHttp3Connection->Fetch(aMethod, aScheme, aAuthorityHeader,
                                        aPath, aHeaders, aStreamId);
  if (NS_FAILED(rv)) {
    LOG(("Http3Session::TryActivating returns error=0x%" PRIx32 "[stream=%p, "
         "this=%p]",
         static_cast<uint32_t>(rv), aStream, this));
    if (rv == NS_BASE_STREAM_WOULD_BLOCK) {
      LOG3(
          ("Http3Session::TryActivating %p stream=%p no room for more "
           "concurrent streams\n",
           this, aStream));
      mTransactionsBlockedByStreamLimitCount++;
      if (mQueuedStreams.GetSize() == 0) {
        mBlockedByStreamLimitCount++;
      }
      QueueStream(aStream);
      return rv;
    }
    // Ignore this error. This may happen if some events are not handled yet.
    // TODO we may try to add an assertion here.
    return NS_OK;
  }

  LOG(("Http3Session::TryActivating streamId=0x%" PRIx64
       " for stream=%p [this=%p].",
       *aStreamId, aStream, this));

  MOZ_ASSERT(*aStreamId != UINT64_MAX);

  if (mTransactionCount > 0 && mStreamIdHash.IsEmpty()) {
    // TODO: investigate why this is failing MOZ_ASSERT(mConnectionIdleStart);
    MOZ_ASSERT(mFirstStreamIdReuseIdleConnection.isNothing());

    mConnectionIdleEnd = TimeStamp::Now();
    mFirstStreamIdReuseIdleConnection = Some(*aStreamId);
  }
  mStreamIdHash.Put(*aStreamId, RefPtr{aStream});
  mTransactionCount++;

  return NS_OK;
}

// This is only called by Http3Stream::OnReadSegment.
// ProcessOutput will be called in Http3Session::ReadSegment that
// calls Http3Stream::OnReadSegment.
void Http3Session::CloseSendingSide(uint64_t aStreamId) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  mHttp3Connection->CloseStream(aStreamId);
}

// This is only called by Http3Stream::OnReadSegment.
// ProcessOutput will be called in Http3Session::ReadSegment that
// calls Http3Stream::OnReadSegment.
nsresult Http3Session::SendRequestBody(uint64_t aStreamId, const char* buf,
                                       uint32_t count, uint32_t* countRead) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  nsresult rv = mHttp3Connection->SendRequestBody(
      aStreamId, (const uint8_t*)buf, count, countRead);
  if (rv == NS_BASE_STREAM_WOULD_BLOCK) {
    mTransactionsSenderBlockedByFlowControlCount++;
  } else if (NS_FAILED(rv)) {
    // Ignore this error. This may happen if some events are not handled yet.
    // TODO we may try to add an assertion here.
    // We will pretend that sender is blocked, that will cause the caller to
    // stop trying.
    *countRead = 0;
    rv = NS_BASE_STREAM_WOULD_BLOCK;
  }

  MOZ_ASSERT((*countRead != 0) || NS_FAILED(rv));
  return rv;
}

void Http3Session::ResetRecvd(uint64_t aStreamId, uint64_t aError) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  RefPtr<Http3Stream> stream = mStreamIdHash.Get(aStreamId);
  if (!stream) {
    return;
  }

  stream->SetRecvdReset();

  // We only handle some of Http3 error as epecial, the rest are just equivalent
  // to cancel.
  if (aError == HTTP3_APP_ERROR_VERSION_FALLBACK) {
    // We will restart the request and the alt-svc will be removed
    // automatically.
    // Also disable http3 we want http1.1.
    stream->Transaction()->DisableHttp3();
    stream->Transaction()->DisableSpdy();
    CloseStream(stream, NS_ERROR_NET_RESET);
  } else if (aError == HTTP3_APP_ERROR_REQUEST_REJECTED) {
    // This request was rejected because server is probably busy or going away.
    // We can restart the request using alt-svc. Without calling
    // DoNotRemoveAltSvc the alt-svc route will be removed.
    stream->Transaction()->DoNotRemoveAltSvc();
    CloseStream(stream, NS_ERROR_NET_RESET);
  } else {
    if (stream->RecvdData()) {
      CloseStream(stream, NS_ERROR_NET_PARTIAL_TRANSFER);
    } else {
      CloseStream(stream, NS_ERROR_NET_INTERRUPT);
    }
  }
}

void Http3Session::SetConnection(nsAHttpConnection* aConn) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  mConnection = aConn;
}

void Http3Session::GetSecurityCallbacks(nsIInterfaceRequestor** aOut) {
  *aOut = nullptr;
}

// TODO
void Http3Session::OnTransportStatus(nsITransport* aTransport, nsresult aStatus,
                                     int64_t aProgress) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");

  if ((aStatus == NS_NET_STATUS_CONNECTED_TO) && !IsConnected()) {
    // We should ignore the event. This is sent by the nsSocketTranpsort
    // and it does not mean that HTTP3 session is connected.
    // We will use this event to mark start of TLS handshake
    aStatus = NS_NET_STATUS_TLS_HANDSHAKE_STARTING;
  }

  switch (aStatus) {
      // These should appear only once, deliver to the first
      // transaction on the session.
    case NS_NET_STATUS_RESOLVING_HOST:
    case NS_NET_STATUS_RESOLVED_HOST:
    case NS_NET_STATUS_CONNECTING_TO:
    case NS_NET_STATUS_CONNECTED_TO:
    case NS_NET_STATUS_TLS_HANDSHAKE_STARTING:
    case NS_NET_STATUS_TLS_HANDSHAKE_ENDED: {
      if (!mFirstHttpTransaction) {
        // if we still do not have a HttpTransaction store timings info in
        // a HttpConnection.
        // If some error occur it can happen that we do not have a connection.
        if (mConnection) {
          RefPtr<HttpConnectionBase> conn = mConnection->HttpConnection();
          conn->SetEvent(aStatus);
        }
      } else {
        mFirstHttpTransaction->OnTransportStatus(aTransport, aStatus,
                                                 aProgress);
      }

      if (aStatus == NS_NET_STATUS_CONNECTED_TO) {
        mFirstHttpTransaction = nullptr;
      }
      break;
    }

    default:
      // The other transport events are ignored here because there is no good
      // way to map them to the right transaction in HTTP3. Instead, the events
      // are generated again from the HTTP3 code and passed directly to the
      // correct transaction.

      // NS_NET_STATUS_SENDING_TO:
      // This is generated by the socket transport when (part) of
      // a transaction is written out
      //
      // There is no good way to map it to the right transaction in HTTP3,
      // so it is ignored here and generated separately when the request
      // is sent from Http3Stream.

      // NS_NET_STATUS_WAITING_FOR:
      // Created by nsHttpConnection when the request has been totally sent.
      // There is no good way to map it to the right transaction in HTTP3,
      // so it is ignored here and generated separately when the same
      // condition is complete in Http3Stream when there is no more
      // request body left to be transmitted.

      // NS_NET_STATUS_RECEIVING_FROM
      // Generated in Http3Stream whenever the stream reads data.

      break;
  }
}

bool Http3Session::IsDone() { return mState == CLOSED; }

nsresult Http3Session::Status() {
  MOZ_ASSERT(false, "Http3Session::Status()");
  return NS_ERROR_UNEXPECTED;
}

uint32_t Http3Session::Caps() {
  MOZ_ASSERT(false, "Http3Session::Caps()");
  return 0;
}

nsresult Http3Session::ReadSegments(nsAHttpSegmentReader* reader,
                                    uint32_t count, uint32_t* countRead) {
  bool again = false;
  return ReadSegmentsAgain(reader, count, countRead, &again);
}

nsresult Http3Session::ReadSegmentsAgain(nsAHttpSegmentReader* reader,
                                         uint32_t count, uint32_t* countRead,
                                         bool* again) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");

  LOG(("Http3Session::ReadSegmentsAgain [this=%p]", this));
  *again = false;

  *countRead = 0;

  //   1) go through all streams/transactions that are ready to write and
  //      write their data into quic streams (no network write yet).
  //   2) call ProcessOutput that will loop until all available packets are
  //      written to a socket or the socket returns an error code.
  //   3) if we still have streams ready to write call ResumeSend()(we may
  //      still have such streams because on an stream error we return earlier
  //      to let the error be handled).

  nsresult rv = NS_OK;
  Http3Stream* stream = nullptr;

  // Step 1)
  while (CanSandData() && (stream = mReadyForWrite.PopFront())) {
    LOG(
        ("Http3Session::ReadSegmentsAgain call ReadSegments from stream=%p "
         "[this=%p]",
         stream, this));

    rv = stream->ReadSegments(this);

    // on stream error we return earlier to let the error be handled.
    if (NS_FAILED(rv)) {
      LOG3(("Http3Session::ReadSegmentsAgain %p returns error code 0x%" PRIx32,
            this, static_cast<uint32_t>(rv)));
      MOZ_ASSERT(rv != NS_BASE_STREAM_WOULD_BLOCK);
      if (rv == NS_BASE_STREAM_WOULD_BLOCK) {  // Just in case!
        rv = NS_OK;
      } else if (ASpdySession::SoftStreamError(rv)) {
        CloseStream(stream, rv);
        LOG3(("Http3Session::ReadSegments %p soft error override\n", this));
        rv = NS_OK;
      } else {
        break;
      }
    }
  }

  if (NS_SUCCEEDED(rv)) {
    // Step 2:
    // Call actuall network write.
    rv = ProcessOutput();
  }

  if (NS_SUCCEEDED(rv)) {
    if (mConnection) {
      Unused << mConnection->ResumeRecv();
    }

    // Step 3:
    MaybeResumeSend();
  }

  if (rv == NS_BASE_STREAM_WOULD_BLOCK) {
    rv = NS_OK;
  }

  return rv;
}

void Http3Session::StreamReadyToWrite(Http3Stream* aStream) {
  MOZ_ASSERT(aStream);
  mReadyForWrite.Push(aStream);
  if (CanSandData() && mConnection) {
    Unused << mConnection->ResumeSend();
  }
}

void Http3Session::MaybeResumeSend() {
  if ((mReadyForWrite.GetSize() > 0) && CanSandData() && mConnection) {
    Unused << mConnection->ResumeSend();
  }
}

nsresult Http3Session::ProcessSlowConsumers() {
  if (mSlowConsumersReadyForRead.IsEmpty()) {
    return NS_OK;
  }

  RefPtr<Http3Stream> slowConsumer = mSlowConsumersReadyForRead.ElementAt(0);
  mSlowConsumersReadyForRead.RemoveElementAt(0);

  uint32_t countRead = 0;
  nsresult rv = ProcessTransactionRead(
      slowConsumer, nsIOService::gDefaultSegmentSize, &countRead);

  return rv;
}

nsresult Http3Session::WriteSegments(nsAHttpSegmentWriter* writer,
                                     uint32_t count, uint32_t* countWritten) {
  bool again = false;
  return WriteSegmentsAgain(writer, count, countWritten, &again);
}

nsresult Http3Session::WriteSegmentsAgain(nsAHttpSegmentWriter* writer,
                                          uint32_t count,
                                          uint32_t* countWritten, bool* again) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  *again = false;

  // Process slow consumers.
  nsresult rv = ProcessSlowConsumers();
  if (NS_FAILED(rv)) {
    LOG3(("Http3Session %p ProcessSlowConsumers returns 0x%" PRIx32 "\n", this,
          static_cast<uint32_t>(rv)));
    return rv;
  }

  rv = ProcessInput(countWritten);
  if (NS_FAILED(rv)) {
    LOG3(("Http3Session %p processInput returns 0x%" PRIx32 "\n", this,
          static_cast<uint32_t>(rv)));
    return rv;
  }
  rv = ProcessEvents(count);
  if (NS_FAILED(rv)) {
    return rv;
  }
  if (mConnection) {
    Unused << mConnection->ResumeRecv();
  }

  // Update timeout and check for new packets to be written.
  // We call ResumeSend to trigger writes if needed.
  uint64_t timeout = mHttp3Connection->ProcessOutput();

  if (mHttp3Connection->HasDataToSend() && mConnection) {
    Unused << mConnection->ResumeSend();
  }
  SetupTimer(timeout);

  return NS_OK;
}

void Http3Session::Close(nsresult aReason) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");

  LOG(("Http3Session::Close [this=%p]", this));

  if (NS_FAILED(mError)) {
    CloseInternal(false);
  } else {
    mError = aReason;
    // If necko closes connection, this will map to "closing" key and 37 in the
    // graph.
    Telemetry::Accumulate(Telemetry::HTTP3_CONNECTTION_CLOSE_CODE, "closing"_ns,
                          37);
    CloseInternal(true);
  }

  if (mCleanShutdown || mIsClosedByNeqo || NS_FAILED(mSocketError)) {
    // It is network-tear-down, a socker error or neqo is state CLOSED
    // (it does not need to send any more packets or wait for new packets).
    // We need to remove all references, so that
    // Http3Session will be destroyed.
    if (mTimer) {
      mTimer->Cancel();
    }
    mConnection = nullptr;
    mSocketTransport = nullptr;
    mSegmentReaderWriter = nullptr;
    mState = CLOSED;
  }
  if (mConnection) {
    // resume sending to send CLOSE_CONNECTION frame.
    Unused << mConnection->ResumeSend();
  }
}

void Http3Session::CloseInternal(bool aCallNeqoClose) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");

  if (IsClosing()) {
    return;
  }

  LOG(("Http3Session::Closing [this=%p]", this));

  if (mState != CONNECTED) {
    mBeforeConnectedError = true;
  }
  mState = CLOSING;
  Shutdown();

  if (aCallNeqoClose) {
    mHttp3Connection->Close(HTTP3_APP_ERROR_NO_ERROR);
  }

  mStreamIdHash.Clear();
  mStreamTransactionHash.Clear();
}

nsHttpConnectionInfo* Http3Session::ConnectionInfo() {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  RefPtr<nsHttpConnectionInfo> ci;
  GetConnectionInfo(getter_AddRefs(ci));
  return ci.get();
}

void Http3Session::SetProxyConnectFailed() {
  MOZ_ASSERT(false, "Http3Session::SetProxyConnectFailed()");
}

nsHttpRequestHead* Http3Session::RequestHead() {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  MOZ_ASSERT(false,
             "Http3Session::RequestHead() "
             "should not be called after http/3 is setup");
  return nullptr;
}

uint32_t Http3Session::Http1xTransactionCount() { return 0; }

nsresult Http3Session::TakeSubTransactions(
    nsTArray<RefPtr<nsAHttpTransaction>>& outTransactions) {
  return NS_OK;
}

//-----------------------------------------------------------------------------
// Pass through methods of nsAHttpConnection
//-----------------------------------------------------------------------------

nsAHttpConnection* Http3Session::Connection() {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  return mConnection;
}

nsresult Http3Session::OnHeadersAvailable(nsAHttpTransaction* transaction,
                                          nsHttpRequestHead* requestHead,
                                          nsHttpResponseHead* responseHead,
                                          bool* reset) {
  MOZ_ASSERT(mConnection);
  if (mConnection) {
    return mConnection->OnHeadersAvailable(transaction, requestHead,
                                           responseHead, reset);
  }
  return NS_OK;
}

bool Http3Session::IsReused() {
  if (mConnection) {
    return mConnection->IsReused();
  }
  return true;
}

nsresult Http3Session::PushBack(const char* buf, uint32_t len) {
  return NS_ERROR_UNEXPECTED;
}

already_AddRefed<HttpConnectionBase> Http3Session::TakeHttpConnection() {
  MOZ_ASSERT(false, "TakeHttpConnection of Http3Session");
  return nullptr;
}

already_AddRefed<HttpConnectionBase> Http3Session::HttpConnection() {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  if (mConnection) {
    return mConnection->HttpConnection();
  }
  return nullptr;
}

void Http3Session::CloseTransaction(nsAHttpTransaction* aTransaction,
                                    nsresult aResult) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  LOG3(("Http3Session::CloseTransaction %p %p 0x%" PRIx32, this, aTransaction,
        static_cast<uint32_t>(aResult)));

  // Generally this arrives as a cancel event from the connection manager.

  // need to find the stream and call CloseStream() on it.
  RefPtr<Http3Stream> stream = mStreamTransactionHash.Get(aTransaction);
  if (!stream) {
    LOG3(("Http3Session::CloseTransaction %p %p 0x%" PRIx32 " - not found.",
          this, aTransaction, static_cast<uint32_t>(aResult)));
    return;
  }
  LOG3(
      ("Http3Session::CloseTransaction probably a cancel. this=%p, "
       "trans=%p, result=0x%" PRIx32 ", streamId=0x%" PRIx64 " stream=%p",
       this, aTransaction, static_cast<uint32_t>(aResult), stream->StreamId(),
       stream.get()));
  CloseStream(stream, aResult);
  if (mConnection) {
    Unused << mConnection->ResumeSend();
  }
}

void Http3Session::CloseStream(Http3Stream* aStream, nsresult aResult) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  if (!aStream->RecvdFin() && !aStream->RecvdReset() &&
      (aStream->HasStreamId())) {
    mHttp3Connection->ResetStream(aStream->StreamId(),
                                  HTTP3_APP_ERROR_REQUEST_CANCELLED);
  }
  aStream->Close(aResult);
  if (aStream->HasStreamId()) {
    // We know the transaction reusing an idle connection has succeeded or
    // failed.
    if (mFirstStreamIdReuseIdleConnection.isSome() &&
        aStream->StreamId() == *mFirstStreamIdReuseIdleConnection) {
      // TODO: investigate why this is failing MOZ_ASSERT(mConnectionIdleStart);
      MOZ_ASSERT(mConnectionIdleEnd);

      if (mConnectionIdleStart) {
        Telemetry::AccumulateTimeDelta(
            Telemetry::HTTP3_TIME_TO_REUSE_IDLE_CONNECTTION_MS,
            NS_SUCCEEDED(aResult) ? "succeeded"_ns : "failed"_ns,
            mConnectionIdleStart, mConnectionIdleEnd);
      }

      mConnectionIdleStart = TimeStamp();
      mConnectionIdleEnd = TimeStamp();
      mFirstStreamIdReuseIdleConnection.reset();
    }

    mStreamIdHash.Remove(aStream->StreamId());

    // Start to idle when we remove the last stream.
    if (mStreamIdHash.IsEmpty()) {
      mConnectionIdleStart = TimeStamp::Now();
    }
  }
  RemoveStreamFromQueues(aStream);
  mStreamTransactionHash.Remove(aStream->Transaction());
  if ((mShouldClose || mGoawayReceived) && !mStreamTransactionHash.Count()) {
    MOZ_ASSERT(!IsClosing());
    Close(NS_OK);
  }
}

nsresult Http3Session::TakeTransport(nsISocketTransport**,
                                     nsIAsyncInputStream**,
                                     nsIAsyncOutputStream**) {
  MOZ_ASSERT(false, "TakeTransport of Http3Session");
  return NS_ERROR_UNEXPECTED;
}

bool Http3Session::IsPersistent() { return true; }

void Http3Session::DontReuse() {
  LOG3(("Http3Session::DontReuse %p\n", this));
  if (!OnSocketThread()) {
    LOG3(("Http3Session %p not on socket thread\n", this));
    nsCOMPtr<nsIRunnable> event = NewRunnableMethod(
        "Http3Session::DontReuse", this, &Http3Session::DontReuse);
    gSocketTransportService->Dispatch(event, NS_DISPATCH_NORMAL);
    return;
  }

  if (mGoawayReceived || IsClosing()) {
    return;
  }

  mShouldClose = true;
  if (!mStreamTransactionHash.Count()) {
    Close(NS_OK);
  }
}

void Http3Session::TopLevelOuterContentWindowIdChanged(uint64_t windowId) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");

  mCurrentForegroundTabOuterContentWindowId = windowId;

  for (auto iter = mStreamTransactionHash.Iter(); !iter.Done(); iter.Next()) {
    iter.Data()->TopLevelOuterContentWindowIdChanged(windowId);
  }
}

nsresult Http3Session::OnReadSegment(const char* buf, uint32_t count,
                                     uint32_t* countRead) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  LOG3(("Http3Session::OnReadSegment"));
  *countRead = 0;
  return NS_OK;
}

nsresult Http3Session::OnWriteSegment(char* buf, uint32_t count,
                                      uint32_t* countWritten) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  LOG3(("Http3Session::OnWriteSegment"));
  *countWritten = 0;
  return NS_OK;
}

// This is called by Http3Stream::OnWriteSegment.
nsresult Http3Session::ReadResponseData(uint64_t aStreamId, char* aBuf,
                                        uint32_t aCount,
                                        uint32_t* aCountWritten, bool* aFin) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");

  nsresult rv = mHttp3Connection->ReadResponseData(aStreamId, (uint8_t*)aBuf,
                                                   aCount, aCountWritten, aFin);

  // This should not happen, i.e. stream must be present in neqo and in necko at
  // the same time.
  MOZ_ASSERT(rv != NS_ERROR_INVALID_ARG);
  if (NS_FAILED(rv)) {
    LOG3(("Http3Session::ReadResponseData return an error %" PRIx32
          " [this=%p]",
          static_cast<uint32_t>(rv), this));
    // This error will be handled by neqo and the whole connection will be
    // closed. We will return NS_BASE_STREAM_WOULD_BLOCK here.
    *aCountWritten = 0;
    *aFin = false;
    rv = NS_BASE_STREAM_WOULD_BLOCK;
  }

  MOZ_ASSERT((*aCountWritten != 0) || aFin || NS_FAILED(rv));
  return rv;
}

void Http3Session::TransactionHasDataToWrite(nsAHttpTransaction* caller) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  LOG3(("Http3Session::TransactionHasDataToWrite %p trans=%p", this, caller));

  // a trapped signal from the http transaction to the connection that
  // it is no longer blocked on read.

  RefPtr<Http3Stream> stream = mStreamTransactionHash.Get(caller);
  if (!stream) {
    LOG3(("Http3Session::TransactionHasDataToWrite %p caller %p not found",
          this, caller));
    return;
  }

  LOG3(("Http3Session::TransactionHasDataToWrite %p ID is 0x%" PRIx64, this,
        stream->StreamId()));

  if (!IsClosing()) {
    StreamReadyToWrite(stream);
  } else {
    LOG3(
        ("Http3Session::TransactionHasDataToWrite %p closed so not setting "
         "Ready4Write\n",
         this));
  }

  // NSPR poll will not poll the network if there are non system PR_FileDesc's
  // that are ready - so we can get into a deadlock waiting for the system IO
  // to come back here if we don't force the send loop manually.
  Unused << ForceSend();
}

void Http3Session::TransactionHasDataToRecv(nsAHttpTransaction* caller) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  LOG3(("Http3Session::TransactionHasDataToRecv %p trans=%p", this, caller));

  // a signal from the http transaction to the connection that it will consume
  // more
  RefPtr<Http3Stream> stream = mStreamTransactionHash.Get(caller);
  if (!stream) {
    LOG3(("Http3Session::TransactionHasDataToRecv %p caller %p not found", this,
          caller));
    return;
  }

  LOG3(("Http3Session::TransactionHasDataToRecv %p ID is 0x%" PRIx64 "\n", this,
        stream->StreamId()));
  ConnectSlowConsumer(stream);
}

void Http3Session::ConnectSlowConsumer(Http3Stream* stream) {
  LOG3(("Http3Session::ConnectSlowConsumer %p 0x%" PRIx64 "\n", this,
        stream->StreamId()));
  mSlowConsumersReadyForRead.AppendElement(stream);
  Unused << ForceRecv();
}

bool Http3Session::TestJoinConnection(const nsACString& hostname,
                                      int32_t port) {
  return RealJoinConnection(hostname, port, true);
}

bool Http3Session::JoinConnection(const nsACString& hostname, int32_t port) {
  return RealJoinConnection(hostname, port, false);
}

// TODO test
bool Http3Session::RealJoinConnection(const nsACString& hostname, int32_t port,
                                      bool justKidding) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  if (!mConnection || !CanSandData() || mShouldClose || mGoawayReceived) {
    return false;
  }

  nsHttpConnectionInfo* ci = ConnectionInfo();
  if (nsCString(hostname).EqualsIgnoreCase(ci->Origin()) &&
      (port == ci->OriginPort())) {
    return true;
  }

  nsAutoCString key(hostname);
  key.Append(':');
  key.Append(justKidding ? 'k' : '.');
  key.AppendInt(port);
  bool cachedResult;
  if (mJoinConnectionCache.Get(key, &cachedResult)) {
    LOG(("joinconnection [%p %s] %s result=%d cache\n", this,
         ConnectionInfo()->HashKey().get(), key.get(), cachedResult));
    return cachedResult;
  }

  nsresult rv;
  bool isJoined = false;

  nsCOMPtr<nsISupports> securityInfo;
  nsCOMPtr<nsISSLSocketControl> sslSocketControl;

  mConnection->GetSecurityInfo(getter_AddRefs(securityInfo));
  sslSocketControl = do_QueryInterface(securityInfo, &rv);
  if (NS_FAILED(rv) || !sslSocketControl) {
    return false;
  }

  bool joinedReturn = false;
  if (justKidding) {
    rv = sslSocketControl->TestJoinConnection(mConnInfo->GetNPNToken(),
                                              hostname, port, &isJoined);
  } else {
    rv = sslSocketControl->JoinConnection(mConnInfo->GetNPNToken(), hostname,
                                          port, &isJoined);
  }
  if (NS_SUCCEEDED(rv) && isJoined) {
    joinedReturn = true;
  }

  LOG(("joinconnection [%p %s] %s result=%d lookup\n", this,
       ConnectionInfo()->HashKey().get(), key.get(), joinedReturn));
  mJoinConnectionCache.Put(key, joinedReturn);
  if (!justKidding) {
    // cache a kidding entry too as this one is good for both
    nsAutoCString key2(hostname);
    key2.Append(':');
    key2.Append('k');
    key2.AppendInt(port);
    if (!mJoinConnectionCache.Get(key2)) {
      mJoinConnectionCache.Put(key2, joinedReturn);
    }
  }
  return joinedReturn;
}

void Http3Session::CallCertVerification() {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  LOG(("Http3Session::CallCertVerification [this=%p]", this));

  NeqoCertificateInfo certInfo;
  if (NS_FAILED(mHttp3Connection->PeerCertificateInfo(&certInfo))) {
    LOG(("Http3Session::CallCertVerification [this=%p] - no cert", this));
    mHttp3Connection->PeerAuthenticated(SSL_ERROR_BAD_CERTIFICATE);
    mError = psm::GetXPCOMFromNSSError(SSL_ERROR_BAD_CERTIFICATE);
    return;
  }

  Maybe<nsTArray<nsTArray<uint8_t>>> stapledOCSPResponse;
  if (certInfo.stapled_ocsp_responses_present) {
    stapledOCSPResponse.emplace(std::move(certInfo.stapled_ocsp_responses));
  }

  Maybe<nsTArray<uint8_t>> sctsFromTLSExtension;
  if (certInfo.signed_cert_timestamp_present) {
    sctsFromTLSExtension.emplace(std::move(certInfo.signed_cert_timestamp));
  }

  mSocketControl->SetAuthenticationCallback(this);
  uint32_t providerFlags;
  // the return value is always NS_OK, just ignore it.
  Unused << mSocketControl->GetProviderFlags(&providerFlags);

  SECStatus rv = AuthCertificateHookWithInfo(
      mSocketControl, static_cast<const void*>(this), std::move(certInfo.certs),
      stapledOCSPResponse, sctsFromTLSExtension, providerFlags);
  if ((rv != SECSuccess) && (rv != SECWouldBlock)) {
    LOG(("Http3Session::CallCertVerification [this=%p] AuthCertificate failed",
         this));
    mHttp3Connection->PeerAuthenticated(SSL_ERROR_BAD_CERTIFICATE);
    mError = psm::GetXPCOMFromNSSError(SSL_ERROR_BAD_CERTIFICATE);
  }
}

void Http3Session::Authenticated(int32_t aError) {
  LOG(("Http3Session::Authenticated error=0x%" PRIx32 " [this=%p].", aError,
       this));
  if ((mState == INITIALIZING) || (mState == ZERORTT)) {
    if (psm::IsNSSErrorCode(aError)) {
      mError = psm::GetXPCOMFromNSSError(aError);
      LOG(("Http3Session::Authenticated psm-error=0x%" PRIx32 " [this=%p].",
           static_cast<uint32_t>(mError), this));
    }
    mHttp3Connection->PeerAuthenticated(aError);

    // Call OnQuicTimeoutExpired to properly process neqo events and outputs.
    // We call OnQuicTimeoutExpired instead of ProcessOutputAndEvents, because
    // HttpConnectionUDP must close this session in case of an error.
    NS_DispatchToCurrentThread(NewRunnableMethod(
        "net::HttpConnectionUDP::OnQuicTimeoutExpired", mSegmentReaderWriter,
        &HttpConnectionUDP::OnQuicTimeoutExpired));
  }
}

void Http3Session::SetSecInfo() {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  NeqoSecretInfo secInfo;
  if (NS_SUCCEEDED(mHttp3Connection->GetSecInfo(&secInfo))) {
    mSocketControl->SetSSLVersionUsed(secInfo.version);
    mSocketControl->SetResumed(secInfo.resumed);

    mSocketControl->SetInfo(secInfo.cipher, secInfo.version, secInfo.group,
                            secInfo.signature_scheme);
  }

  if (!mSocketControl->HasServerCert() &&
      StaticPrefs::network_ssl_tokens_cache_enabled()) {
    mSocketControl->RebuildCertificateInfoFromSSLTokenCache();
  }
}

void Http3Session::CloseConnectionTelemetry(CloseError& aError, bool aClosing) {
  uint64_t value = 0;

  switch (aError.tag) {
    case CloseError::Tag::QuicTransportError:
      // Transport error have values from 0 to 12.
      // (https://tools.ietf.org/html/draft-ietf-quic-transport-24#section-20)
      // We will map this error to 0-12.
      // 13 wil capture error codes between and including 13 and 0x0ff. This
      // error codes are not define by the spec but who know peer may sent them.
      // CryptoAlerts have value 0x100 + alert code. For now we will map them
      // to 14. (https://tools.ietf.org/html/draft-ietf-quic-tls-24#section-4.9)
      // (telemetry does not allow more than 100 bucket and to easily map alerts
      // we need 256. If we find problem with too many alerts we could map
      // them.)
      if (aError.quic_transport_error._0 <= 12) {
        value = aError.quic_transport_error._0;
      } else if (aError.quic_transport_error._0 < 0x100) {
        value = 13;
      } else {
        value = 14;
      }
      break;
    case CloseError::Tag::Http3AppError:
      if (aError.http3_app_error._0 <= 0x110) {
        // Http3 error codes are 0x100-0x110.
        // (https://tools.ietf.org/html/draft-ietf-quic-http-24#section-8.1)
        // The will be mapped to 15-31.
        value = (aError.http3_app_error._0 - 0x100) + 15;
      } else if (aError.http3_app_error._0 < 0x200) {
        // Error codes between 0x111 and 0x1ff are not defined and will be
        // mapped int 32
        value = 32;  // 0x11 + 15
      } else if (aError.http3_app_error._0 < 0x203) {
        // Error codes between 0x200 and 0x202 are related to qpack.
        // (https://tools.ietf.org/html/draft-ietf-quic-qpack-11#section-6)
        // They will be mapped to 33-35
        value = aError.http3_app_error._0 - 0x200 + 33;
      } else {
        value = 36;
      }
  }

  // A connection may be closed in two ways: client side closes connection or
  // server side. In former case http3 state will first change to closing state
  // in the later case itt will change to closed. In tthis way we can
  // distinguish which side is closing connecttion first. If necko closes
  // connection, this will map to "closing" key and 37 in the graph.
  Telemetry::Accumulate(Telemetry::HTTP3_CONNECTTION_CLOSE_CODE,
                        aClosing ? "closing"_ns : "closed"_ns, value);

  Http3Stats stats;
  mHttp3Connection->GetStats(&stats);

  if (stats.packets_tx > 0) {
    unsigned long loss = (stats.lost * 10000) / stats.packets_tx;
    Telemetry::Accumulate(Telemetry::HTTP3_LOSS_RATIO, loss);

    Telemetry::Accumulate(Telemetry::HTTP3_LATE_ACK, "ack"_ns, stats.late_ack);
    Telemetry::Accumulate(Telemetry::HTTP3_LATE_ACK, "pto"_ns, stats.pto_ack);

    unsigned long late_ack_ratio = (stats.late_ack * 10000) / stats.packets_tx;
    unsigned long pto_ack_ratio = (stats.pto_ack * 10000) / stats.packets_tx;
    Telemetry::Accumulate(Telemetry::HTTP3_LATE_ACK_RATIO, "ack"_ns,
                          late_ack_ratio);
    Telemetry::Accumulate(Telemetry::HTTP3_LATE_ACK_RATIO, "pto"_ns,
                          pto_ack_ratio);

    for (uint32_t i = 0; i < MAX_PTO_COUNTS; i++) {
      nsAutoCString key;
      key.AppendInt(i);
      Telemetry::Accumulate(Telemetry::HTTP3_COUNTS_PTO, key,
                            stats.pto_counts[i]);
    }

    Telemetry::Accumulate(Telemetry::HTTP3_DROP_DGRAMS, stats.dropped_rx);
    Telemetry::Accumulate(Telemetry::HTTP3_SAVED_DGRAMS, stats.saved_datagrams);
  }

  Telemetry::Accumulate(Telemetry::HTTP3_RECEIVED_SENT_DGRAMS, "received"_ns,
                        stats.packets_rx);
  Telemetry::Accumulate(Telemetry::HTTP3_RECEIVED_SENT_DGRAMS, "sent"_ns,
                        stats.packets_tx);
}

void Http3Session::Finish0Rtt(bool aRestart) {
  for (size_t i = 0; i < m0RTTStreams.Length(); ++i) {
    if (m0RTTStreams[i]) {
      if (aRestart) {
        // When we need to restart transactions remove them from all lists.
        if (m0RTTStreams[i]->HasStreamId()) {
          mStreamIdHash.Remove(m0RTTStreams[i]->StreamId());
        }
        RemoveStreamFromQueues(m0RTTStreams[i]);
        // The stream is ready to write again.
        mReadyForWrite.Push(m0RTTStreams[i]);
      }
      m0RTTStreams[i]->Finish0RTT(aRestart);
    }
  }

  for (size_t i = 0; i < mCannotDo0RTTStreams.Length(); ++i) {
    if (mCannotDo0RTTStreams[i]) {
      mReadyForWrite.Push(mCannotDo0RTTStreams[i]);
    }
  }
  m0RTTStreams.Clear();
  mCannotDo0RTTStreams.Clear();
  MaybeResumeSend();
}

void Http3Session::ReportHttp3Connection() {
  if (CanSandData() && !mHttp3ConnectionReported) {
    mHttp3ConnectionReported = true;
    gHttpHandler->ConnMgr()->ReportHttp3Connection(mSegmentReaderWriter);
    MaybeResumeSend();
  }
}

}  // namespace net
}  // namespace mozilla