Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2478 insertions, 0 deletions

diff --git a/netwerk/protocol/http/Http3Session.cpp b/netwerk/protocol/http/Http3Session.cpp
new file mode 100644
index 0000000000..d2a5f4ed9b
--- /dev/null
+++ b/netwerk/protocol/http/Http3Session.cpp
@@ -0,0 +1,2478 @@
+/* -*- 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 "ASpdySession.h"  // because of SoftStreamError()
+#include "Http3Session.h"
+#include "Http3Stream.h"
+#include "Http3StreamBase.h"
+#include "Http3WebTransportSession.h"
+#include "Http3WebTransportStream.h"
+#include "HttpConnectionUDP.h"
+#include "HttpLog.h"
+#include "QuicSocketControl.h"
+#include "SSLServerCertVerification.h"
+#include "SSLTokensCache.h"
+#include "ScopedNSSTypes.h"
+#include "mozilla/RandomNum.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/net/DNS.h"
+#include "nsHttpHandler.h"
+#include "nsIHttpActivityObserver.h"
+#include "nsIOService.h"
+#include "nsITLSSocketControl.h"
+#include "nsNetAddr.h"
+#include "nsQueryObject.h"
+#include "nsSocketTransportService2.h"
+#include "nsThreadUtils.h"
+#include "sslerr.h"
+
+namespace mozilla::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;
+
+const uint32_t TRANSPORT_ERROR_STATELESS_RESET = 20;
+
+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() {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+  LOG(("Http3Session::Http3Session [this=%p]", this));
+
+  mCurrentBrowserId = gHttpHandler->ConnMgr()->CurrentBrowserId();
+  mThroughCaptivePortal = gHttpHandler->GetThroughCaptivePortal();
+}
+
+static nsresult StringAndPortToNetAddr(nsACString& remoteAddrStr,
+                                       uint16_t remotePort, NetAddr* netAddr) {
+  if (NS_FAILED(netAddr->InitFromString(remoteAddrStr, remotePort))) {
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+nsresult Http3Session::Init(const nsHttpConnectionInfo* aConnInfo,
+                            nsINetAddr* aSelfAddr, nsINetAddr* aPeerAddr,
+                            HttpConnectionUDP* udpConn, uint32_t controlFlags,
+                            nsIInterfaceRequestor* callbacks) {
+  LOG3(("Http3Session::Init %p", this));
+
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+  MOZ_ASSERT(udpConn);
+
+  mConnInfo = aConnInfo->Clone();
+  mNetAddr = aPeerAddr;
+
+  bool httpsProxy =
+      aConnInfo->ProxyInfo() ? aConnInfo->ProxyInfo()->IsHTTPS() : false;
+
+  // Create security control and info object for quic.
+  mSocketControl = new QuicSocketControl(
+      httpsProxy ? aConnInfo->ProxyInfo()->Host() : aConnInfo->GetOrigin(),
+      httpsProxy ? aConnInfo->ProxyInfo()->Port() : aConnInfo->OriginPort(),
+      controlFlags, this);
+
+  NetAddr selfAddr;
+  MOZ_ALWAYS_SUCCEEDS(aSelfAddr->GetNetAddr(&selfAddr));
+  NetAddr peerAddr;
+  MOZ_ALWAYS_SUCCEEDS(aPeerAddr->GetNetAddr(&peerAddr));
+
+  LOG3(
+      ("Http3Session::Init origin=%s, alpn=%s, selfAddr=%s, peerAddr=%s,"
+       " qpack table size=%u, max blocked streams=%u webtransport=%d "
+       "[this=%p]",
+       PromiseFlatCString(mConnInfo->GetOrigin()).get(),
+       PromiseFlatCString(mConnInfo->GetNPNToken()).get(),
+       selfAddr.ToString().get(), peerAddr.ToString().get(),
+       gHttpHandler->DefaultQpackTableSize(),
+       gHttpHandler->DefaultHttp3MaxBlockedStreams(),
+       mConnInfo->GetWebTransport(), this));
+
+  if (mConnInfo->GetWebTransport()) {
+    mWebTransportNegotiationStatus = WebTransportNegotiation::NEGOTIATING;
+  }
+
+  uint32_t datagramSize =
+      StaticPrefs::network_webtransport_datagrams_enabled()
+          ? StaticPrefs::network_webtransport_datagram_size()
+          : 0;
+  nsresult rv = NeqoHttp3Conn::Init(
+      mConnInfo->GetOrigin(), mConnInfo->GetNPNToken(), selfAddr, peerAddr,
+      gHttpHandler->DefaultQpackTableSize(),
+      gHttpHandler->DefaultHttp3MaxBlockedStreams(),
+      StaticPrefs::network_http_http3_max_data(),
+      StaticPrefs::network_http_http3_max_stream_data(),
+      StaticPrefs::network_http_http3_version_negotiation_enabled(),
+      mConnInfo->GetWebTransport(), gHttpHandler->Http3QlogDir(), datagramSize,
+      getter_AddRefs(mHttp3Connection));
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  nsAutoCString peerId;
+  mSocketControl->GetPeerId(peerId);
+  nsTArray<uint8_t> token;
+  SessionCacheInfo info;
+  if (StaticPrefs::network_http_http3_enable_0rtt() &&
+      NS_SUCCEEDED(SSLTokensCache::Get(peerId, token, info))) {
+    LOG(("Found a resumption token in the cache."));
+    mHttp3Connection->SetResumptionToken(token);
+    mSocketControl->SetSessionCacheInfo(std::move(info));
+    if (mHttp3Connection->IsZeroRtt()) {
+      LOG(("Can send ZeroRtt data"));
+      RefPtr<Http3Session> self(this);
+      mState = ZERORTT;
+      mZeroRttStarted = TimeStamp::Now();
+      // 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");
+    }
+  }
+
+  if (mState != ZERORTT) {
+    ZeroRttTelemetry(ZeroRttOutcome::NOT_USED);
+  }
+
+  auto config = mConnInfo->GetEchConfig();
+  if (config.IsEmpty()) {
+    if (StaticPrefs::security_tls_ech_grease_http3() && config.IsEmpty()) {
+      if ((RandomUint64().valueOr(0) % 100) >=
+          100 - StaticPrefs::security_tls_ech_grease_probability()) {
+        // Setting an empty config enables GREASE mode.
+        mSocketControl->SetEchConfig(config);
+        mEchExtensionStatus = EchExtensionStatus::kGREASE;
+      }
+    }
+  } else if (gHttpHandler->EchConfigEnabled(true) && !config.IsEmpty()) {
+    mSocketControl->SetEchConfig(config);
+    mEchExtensionStatus = EchExtensionStatus::kReal;
+    HttpConnectionActivity activity(
+        mConnInfo->HashKey(), mConnInfo->GetOrigin(), mConnInfo->OriginPort(),
+        mConnInfo->EndToEndSSL(), !mConnInfo->GetEchConfig().IsEmpty(),
+        mConnInfo->IsHttp3());
+    gHttpHandler->ObserveHttpActivityWithArgs(
+        activity, NS_ACTIVITY_TYPE_HTTP_CONNECTION,
+        NS_HTTP_ACTIVITY_SUBTYPE_ECH_SET, PR_Now(), 0, ""_ns);
+  } else {
+    mEchExtensionStatus = EchExtensionStatus::kNotPresent;
+  }
+
+  // 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.
+  mUdpConn = udpConn;
+  return NS_OK;
+}
+
+void Http3Session::DoSetEchConfig(const nsACString& aEchConfig) {
+  LOG(("Http3Session::DoSetEchConfig %p of length %zu", this,
+       aEchConfig.Length()));
+  nsTArray<uint8_t> config;
+  config.AppendElements(
+      reinterpret_cast<const uint8_t*>(aEchConfig.BeginReading()),
+      aEchConfig.Length());
+  mHttp3Connection->SetEchConfig(config);
+}
+
+nsresult Http3Session::SendPriorityUpdateFrame(uint64_t aStreamId,
+                                               uint8_t aPriorityUrgency,
+                                               bool aPriorityIncremental) {
+  return mHttp3Connection->PriorityUpdate(aStreamId, aPriorityUrgency,
+                                          aPriorityIncremental);
+}
+
+// Shutdown the http3session and close all transactions.
+void Http3Session::Shutdown() {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+
+  if (mTimer) {
+    mTimer->Cancel();
+  }
+  mTimer = nullptr;
+
+  bool isEchRetry = mError == mozilla::psm::GetXPCOMFromNSSError(
+                                  SSL_ERROR_ECH_RETRY_WITH_ECH);
+  bool allowToRetryWithDifferentIPFamily =
+      mBeforeConnectedError &&
+      gHttpHandler->ConnMgr()->AllowToRetryDifferentIPFamilyForHttp3(mConnInfo,
+                                                                     mError);
+  LOG(("Http3Session::Shutdown %p allowToRetryWithDifferentIPFamily=%d", this,
+       allowToRetryWithDifferentIPFamily));
+  if ((mBeforeConnectedError ||
+       (mError == NS_ERROR_NET_HTTP3_PROTOCOL_ERROR)) &&
+      (mError !=
+       mozilla::psm::GetXPCOMFromNSSError(SSL_ERROR_BAD_CERT_DOMAIN)) &&
+      !isEchRetry && !mConnInfo->GetWebTransport() &&
+      !allowToRetryWithDifferentIPFamily && !mDontExclude) {
+    gHttpHandler->ExcludeHttp3(mConnInfo);
+  }
+
+  for (const auto& stream : mStreamTransactionHash.Values()) {
+    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));
+      if (isEchRetry) {
+        // We have to propagate this error to nsHttpTransaction, so the
+        // transaction will be restarted with a new echConfig.
+        stream->Close(mError);
+      } else {
+        if (allowToRetryWithDifferentIPFamily && mNetAddr) {
+          NetAddr addr;
+          mNetAddr->GetNetAddr(&addr);
+          gHttpHandler->ConnMgr()->SetRetryDifferentIPFamilyForHttp3(
+              mConnInfo, addr.raw.family);
+          nsHttpTransaction* trans =
+              stream->Transaction()->QueryHttpTransaction();
+          if (trans) {
+            // This is a bit hacky. We redispatch the transaction here to avoid
+            // touching the complicated retry logic in nsHttpTransaction.
+            trans->RemoveConnection();
+            Unused << gHttpHandler->InitiateTransaction(trans,
+                                                        trans->Priority());
+          } else {
+            stream->Close(NS_ERROR_NET_RESET);
+          }
+          // Since Http3Session::Shutdown can be called multiple times, we set
+          // mDontExclude for not putting this domain into the excluded list.
+          mDontExclude = true;
+        } else {
+          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->GetHttp3Stream() &&
+               stream->GetHttp3Stream()->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 if (mError == NS_ERROR_NET_RESET) {
+      stream->Close(NS_ERROR_NET_RESET);
+    } else {
+      stream->Close(NS_ERROR_ABORT);
+    }
+    RemoveStreamFromQueues(stream);
+    if (stream->HasStreamId()) {
+      mStreamIdHash.Remove(stream->StreamId());
+    }
+  }
+  mStreamTransactionHash.Clear();
+
+  for (const auto& stream : mWebTransportSessions) {
+    stream->Close(NS_ERROR_ABORT);
+    RemoveStreamFromQueues(stream);
+    mStreamIdHash.Remove(stream->StreamId());
+  }
+  mWebTransportSessions.Clear();
+
+  for (const auto& stream : mWebTransportStreams) {
+    stream->Close(NS_ERROR_ABORT);
+    RemoveStreamFromQueues(stream);
+    mStreamIdHash.Remove(stream->StreamId());
+  }
+  mWebTransportStreams.Clear();
+}
+
+Http3Session::~Http3Session() {
+  LOG3(("Http3Session::~Http3Session %p", this));
+
+  EchOutcomeTelemetry();
+  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);
+
+  if (mThroughCaptivePortal) {
+    if (mTotalBytesRead || mTotalBytesWritten) {
+      auto total =
+          Clamp<uint32_t>((mTotalBytesRead >> 10) + (mTotalBytesWritten >> 10),
+                          0, std::numeric_limits<uint32_t>::max());
+      Telemetry::ScalarAdd(
+          Telemetry::ScalarID::NETWORKING_DATA_TRANSFERRED_CAPTIVE_PORTAL,
+          total);
+    }
+
+    Telemetry::ScalarAdd(
+        Telemetry::ScalarID::NETWORKING_HTTP_CONNECTIONS_CAPTIVE_PORTAL, 1);
+  }
+
+  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::RecvData ->
+//   Http3Session::RecvData
+void Http3Session::ProcessInput(nsIUDPSocket* socket) {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+  MOZ_ASSERT(mUdpConn);
+
+  LOG(("Http3Session::ProcessInput writer=%p [this=%p state=%d]",
+       mUdpConn.get(), this, mState));
+
+  while (true) {
+    nsTArray<uint8_t> data;
+    NetAddr addr{};
+    // RecvWithAddr actually does not return an error.
+    nsresult rv = socket->RecvWithAddr(&addr, data);
+    MOZ_ALWAYS_SUCCEEDS(rv);
+    if (NS_FAILED(rv) || data.IsEmpty()) {
+      break;
+    }
+    rv = mHttp3Connection->ProcessInput(addr, data);
+    MOZ_ALWAYS_SUCCEEDS(rv);
+    if (NS_FAILED(rv)) {
+      break;
+    }
+
+    LOG(("Http3Session::ProcessInput received=%zu", data.Length()));
+    mTotalBytesRead += data.Length();
+  }
+}
+
+nsresult Http3Session::ProcessTransactionRead(uint64_t stream_id) {
+  RefPtr<Http3StreamBase> 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);
+}
+
+nsresult Http3Session::ProcessTransactionRead(Http3StreamBase* stream) {
+  nsresult rv = stream->WriteSegments();
+
+  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() {
+  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<Http3StreamBase> stream = mStreamIdHash.Get(id);
+        if (!stream) {
+          LOG(
+              ("Http3Session::ProcessEvents - HeaderReady - stream not found "
+               "stream_id=0x%" PRIx64 " [this=%p].",
+               id, this));
+          break;
+        }
+
+        MOZ_RELEASE_ASSERT(stream->GetHttp3Stream(),
+                           "This must be a Http3Stream");
+
+        stream->SetResponseHeaders(data, event.header_ready.fin,
+                                   event.header_ready.interim);
+
+        rv = ProcessTransactionRead(stream);
+
+        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;
+
+        nsresult rv = ProcessTransactionRead(id);
+
+        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<Http3StreamBase> stream =
+            mStreamIdHash.Get(event.data_writable.stream_id);
+
+        if (stream) {
+          StreamReadyToWrite(stream);
+        }
+      } break;
+      case Http3Event::Tag::Reset:
+        LOG(("Http3Session::ProcessEvents %p - Reset", this));
+        ResetOrStopSendingRecvd(event.reset.stream_id, event.reset.error,
+                                RESET);
+        break;
+      case Http3Event::Tag::StopSending:
+        LOG(
+            ("Http3Session::ProcessEvents %p - StopSeniding with error "
+             "0x%" PRIx64,
+             this, event.stop_sending.error));
+        if (event.stop_sending.error == HTTP3_APP_ERROR_NO_ERROR) {
+          RefPtr<Http3StreamBase> stream =
+              mStreamIdHash.Get(event.data_writable.stream_id);
+          if (stream) {
+            RefPtr<Http3Stream> httpStream = stream->GetHttp3Stream();
+            MOZ_RELEASE_ASSERT(httpStream, "This must be a Http3Stream");
+            httpStream->StopSending();
+          }
+        } else {
+          ResetOrStopSendingRecvd(event.reset.stream_id, event.reset.error,
+                                  STOP_SENDING);
+        }
+        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(Nothing());
+        }
+        break;
+      case Http3Event::Tag::ZeroRttRejected:
+        LOG(("Http3Session::ProcessEvents - ZeroRttRejected"));
+        if (mState == ZERORTT) {
+          mState = INITIALIZING;
+          mTransactionCount = 0;
+          Finish0Rtt(true);
+          ZeroRttTelemetry(ZeroRttOutcome::USED_REJECTED);
+        }
+        break;
+      case Http3Event::Tag::ResumptionToken: {
+        LOG(("Http3Session::ProcessEvents - ResumptionToken"));
+        if (StaticPrefs::network_http_http3_enable_0rtt() && !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);
+          ZeroRttTelemetry(ZeroRttOutcome::USED_SUCCEEDED);
+        }
+
+        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();
+        // Maybe call ResumeSend:
+        // In case ZeroRtt has been used and it has been rejected, 2 events will
+        // be received: ZeroRttRejected and ConnectionConnected. ZeroRttRejected
+        // that will put all transaction into mReadyForWrite queue and it will
+        // call MaybeResumeSend, but that will not have an effect because the
+        // connection is ont in CONNECTED state. When ConnectionConnected event
+        // is received call MaybeResumeSend to trigger reads for the
+        // zero-rtt-rejected transactions.
+        MaybeResumeSend();
+      } 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);
+
+          auto isStatelessResetOrNoError = [](CloseError& aError) -> bool {
+            if (aError.tag == CloseError::Tag::TransportInternalErrorOther &&
+                aError.transport_internal_error_other._0 ==
+                    TRANSPORT_ERROR_STATELESS_RESET) {
+              return true;
+            }
+            if (aError.tag == CloseError::Tag::TransportError &&
+                aError.transport_error._0 == 0) {
+              return true;
+            }
+            if (aError.tag == CloseError::Tag::PeerError &&
+                aError.peer_error._0 == 0) {
+              return true;
+            }
+            if (aError.tag == CloseError::Tag::AppError &&
+                aError.app_error._0 == HTTP3_APP_ERROR_NO_ERROR) {
+              return true;
+            }
+            if (aError.tag == CloseError::Tag::PeerAppError &&
+                aError.peer_app_error._0 == HTTP3_APP_ERROR_NO_ERROR) {
+              return true;
+            }
+            return false;
+          };
+          if (isStatelessResetOrNoError(event.connection_closing.error)) {
+            mError = NS_ERROR_NET_RESET;
+          }
+          if (event.connection_closing.error.tag == CloseError::Tag::EchRetry) {
+            mSocketControl->SetRetryEchConfig(Substring(
+                reinterpret_cast<const char*>(data.Elements()), data.Length()));
+            mError = psm::GetXPCOMFromNSSError(SSL_ERROR_ECH_RETRY_WITH_ECH);
+          }
+        }
+        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;
+        if (event.connection_closed.error.tag == CloseError::Tag::EchRetry) {
+          mSocketControl->SetRetryEchConfig(Substring(
+              reinterpret_cast<const char*>(data.Elements()), data.Length()));
+          mError = psm::GetXPCOMFromNSSError(SSL_ERROR_ECH_RETRY_WITH_ECH);
+        }
+        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;
+      case Http3Event::Tag::EchFallbackAuthenticationNeeded: {
+        nsCString echPublicName(reinterpret_cast<const char*>(data.Elements()),
+                                data.Length());
+        LOG(
+            ("Http3Session::ProcessEvents - EchFallbackAuthenticationNeeded "
+             "echPublicName=%s",
+             echPublicName.get()));
+        if (!mAuthenticationStarted) {
+          mAuthenticationStarted = true;
+          CallCertVerification(Some(echPublicName));
+        }
+      } break;
+      case Http3Event::Tag::WebTransport: {
+        switch (event.web_transport._0.tag) {
+          case WebTransportEventExternal::Tag::Negotiated:
+            LOG(("Http3Session::ProcessEvents - WebTransport %d",
+                 event.web_transport._0.negotiated._0));
+            MOZ_ASSERT(mWebTransportNegotiationStatus ==
+                       WebTransportNegotiation::NEGOTIATING);
+            mWebTransportNegotiationStatus =
+                event.web_transport._0.negotiated._0
+                    ? WebTransportNegotiation::SUCCEEDED
+                    : WebTransportNegotiation::FAILED;
+            WebTransportNegotiationDone();
+            break;
+          case WebTransportEventExternal::Tag::Session: {
+            MOZ_ASSERT(mState == CONNECTED);
+
+            uint64_t id = event.web_transport._0.session._0;
+            LOG(
+                ("Http3Session::ProcessEvents - WebTransport Session "
+                 " sessionId=0x%" PRIx64,
+                 id));
+            RefPtr<Http3StreamBase> stream = mStreamIdHash.Get(id);
+            if (!stream) {
+              LOG(
+                  ("Http3Session::ProcessEvents - WebTransport Session - "
+                   "stream not found "
+                   "stream_id=0x%" PRIx64 " [this=%p].",
+                   id, this));
+              break;
+            }
+
+            MOZ_RELEASE_ASSERT(stream->GetHttp3WebTransportSession(),
+                               "It must be a WebTransport session");
+            stream->SetResponseHeaders(data, false, false);
+
+            rv = stream->WriteSegments();
+
+            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.get(), stream->StreamId(),
+                   static_cast<uint32_t>(rv), stream->Done()));
+              // We need to keep the transaction, so we can use it to remove the
+              // stream from mStreamTransactionHash.
+              nsAHttpTransaction* trans = stream->Transaction();
+              if (mStreamTransactionHash.Contains(trans)) {
+                CloseStream(stream, (rv == NS_BINDING_RETARGETED)
+                                        ? NS_BINDING_RETARGETED
+                                        : NS_OK);
+                mStreamTransactionHash.Remove(trans);
+              } else {
+                stream->GetHttp3WebTransportSession()->TransactionIsDone(
+                    (rv == NS_BINDING_RETARGETED) ? NS_BINDING_RETARGETED
+                                                  : NS_OK);
+              }
+              break;
+            }
+
+            if (NS_FAILED(rv) && rv != NS_BASE_STREAM_WOULD_BLOCK) {
+              LOG(("Http3Session::ProcessEvents [this=%p] rv=%" PRIx32, this,
+                   static_cast<uint32_t>(rv)));
+              return rv;
+            }
+          } break;
+          case WebTransportEventExternal::Tag::SessionClosed: {
+            uint64_t id = event.web_transport._0.session_closed.stream_id;
+            LOG(
+                ("Http3Session::ProcessEvents - WebTransport SessionClosed "
+                 " sessionId=0x%" PRIx64,
+                 id));
+            RefPtr<Http3StreamBase> stream = mStreamIdHash.Get(id);
+            if (!stream) {
+              LOG(
+                  ("Http3Session::ProcessEvents - WebTransport SessionClosed - "
+                   "stream not found "
+                   "stream_id=0x%" PRIx64 " [this=%p].",
+                   id, this));
+              break;
+            }
+
+            RefPtr<Http3WebTransportSession> wt =
+                stream->GetHttp3WebTransportSession();
+            MOZ_RELEASE_ASSERT(wt, "It must be a WebTransport session");
+
+            // TODO we do not handle the case when a WebTransport session stream
+            // is closed before headers are sent.
+            SessionCloseReasonExternal& reasonExternal =
+                event.web_transport._0.session_closed.reason;
+            uint32_t status = 0;
+            nsCString reason = ""_ns;
+            if (reasonExternal.tag == SessionCloseReasonExternal::Tag::Error) {
+              status = reasonExternal.error._0;
+            } else if (reasonExternal.tag ==
+                       SessionCloseReasonExternal::Tag::Status) {
+              status = reasonExternal.status._0;
+            } else {
+              status = reasonExternal.clean._0;
+              reason.Assign(reinterpret_cast<const char*>(data.Elements()),
+                            data.Length());
+            }
+            LOG(("reason.tag=%u err=%u data=%s\n",
+                 static_cast<uint32_t>(reasonExternal.tag), status,
+                 reason.get()));
+            wt->OnSessionClosed(status, reason);
+
+          } break;
+          case WebTransportEventExternal::Tag::NewStream: {
+            LOG(
+                ("Http3Session::ProcessEvents - WebTransport NewStream "
+                 "streamId=0x%" PRIx64 " sessionId=0x%" PRIx64,
+                 event.web_transport._0.new_stream.stream_id,
+                 event.web_transport._0.new_stream.session_id));
+            uint64_t sessionId = event.web_transport._0.new_stream.session_id;
+            RefPtr<Http3StreamBase> stream = mStreamIdHash.Get(sessionId);
+            if (!stream) {
+              LOG(
+                  ("Http3Session::ProcessEvents - WebTransport NewStream - "
+                   "session not found "
+                   "sessionId=0x%" PRIx64 " [this=%p].",
+                   sessionId, this));
+              break;
+            }
+
+            RefPtr<Http3WebTransportSession> wt =
+                stream->GetHttp3WebTransportSession();
+            if (!wt) {
+              break;
+            }
+
+            RefPtr<Http3WebTransportStream> wtStream =
+                wt->OnIncomingWebTransportStream(
+                    event.web_transport._0.new_stream.stream_type,
+                    event.web_transport._0.new_stream.stream_id);
+            if (!wtStream) {
+              break;
+            }
+
+            // WebTransportStream is managed by Http3Session now.
+            mWebTransportStreams.AppendElement(wtStream);
+            mWebTransportStreamToSessionMap.InsertOrUpdate(wtStream->StreamId(),
+                                                           wt->StreamId());
+            mStreamIdHash.InsertOrUpdate(wtStream->StreamId(),
+                                         std::move(wtStream));
+          } break;
+          case WebTransportEventExternal::Tag::Datagram:
+            LOG(
+                ("Http3Session::ProcessEvents - "
+                 "WebTransportEventExternal::Tag::Datagram [this=%p]",
+                 this));
+            uint64_t sessionId = event.web_transport._0.datagram.session_id;
+            RefPtr<Http3StreamBase> stream = mStreamIdHash.Get(sessionId);
+            if (!stream) {
+              LOG(
+                  ("Http3Session::ProcessEvents - WebTransport Datagram - "
+                   "session not found "
+                   "sessionId=0x%" PRIx64 " [this=%p].",
+                   sessionId, this));
+              break;
+            }
+
+            RefPtr<Http3WebTransportSession> wt =
+                stream->GetHttp3WebTransportSession();
+            if (!wt) {
+              break;
+            }
+
+            wt->OnDatagramReceived(std::move(data));
+            break;
+        }
+      } 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::SendData ->
+//      Http3Session::SendData
+nsresult Http3Session::ProcessOutput(nsIUDPSocket* socket) {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+  MOZ_ASSERT(mUdpConn);
+
+  LOG(("Http3Session::ProcessOutput reader=%p, [this=%p]", mUdpConn.get(),
+       this));
+
+  // Check if we have a packet that could not have been sent in a previous
+  // iteration or maybe get new packets to send.
+  while (true) {
+    nsTArray<uint8_t> packetToSend;
+    nsAutoCString remoteAddrStr;
+    uint16_t port = 0;
+    uint64_t timeout = 0;
+    if (!mHttp3Connection->ProcessOutput(&remoteAddrStr, &port, packetToSend,
+                                         &timeout)) {
+      SetupTimer(timeout);
+      break;
+    }
+    MOZ_ASSERT(packetToSend.Length());
+    LOG(
+        ("Http3Session::ProcessOutput sending packet with %u bytes to %s "
+         "port=%d [this=%p].",
+         (uint32_t)packetToSend.Length(),
+         PromiseFlatCString(remoteAddrStr).get(), port, this));
+
+    uint32_t written = 0;
+    NetAddr addr;
+    if (NS_FAILED(StringAndPortToNetAddr(remoteAddrStr, port, &addr))) {
+      continue;
+    }
+    nsresult rv = socket->SendWithAddress(&addr, packetToSend, &written);
+
+    LOG(("Http3Session::ProcessOutput sending packet rv=%d osError=%d",
+         static_cast<int32_t>(rv), NS_FAILED(rv) ? PR_GetOSError() : 0));
+    if (NS_FAILED(rv) && (rv != NS_BASE_STREAM_WOULD_BLOCK)) {
+      mSocketError = rv;
+      // If there was an error that is not NS_BASE_STREAM_WOULD_BLOCK
+      // return from here. We do not need to set a timer, because we
+      // will close the connection.
+      return rv;
+    }
+    mTotalBytesWritten += packetToSend.Length();
+    mLastWriteTime = PR_IntervalNow();
+  }
+
+  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(nsIUDPSocket* socket) {
+  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(socket);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  return ProcessEvents();
+}
+
+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;
+  }
+
+  nsresult rv = NS_NewTimerWithCallback(
+      getter_AddRefs(mTimer),
+      [conn = RefPtr{mUdpConn}](nsITimer*) { conn->OnQuicTimeoutExpired(); },
+      aTimeout, nsITimer::TYPE_ONE_SHOT,
+      "net::HttpConnectionUDP::OnQuicTimeout");
+
+  mTimerActive = true;
+
+  if (NS_FAILED(rv)) {
+    NS_DispatchToCurrentThread(
+        NewRunnableMethod("net::HttpConnectionUDP::OnQuicTimeoutExpired",
+                          mUdpConn, &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();
+  // reset the read timers to wash away any idle time
+  mLastWriteTime = PR_IntervalNow();
+
+  ClassOfService cos;
+  if (trans) {
+    cos = trans->GetClassOfService();
+  }
+
+  Http3StreamBase* stream = nullptr;
+
+  if (trans && trans->IsForWebTransport()) {
+    LOG3(("Http3Session::AddStream new  WeTransport session %p atrans=%p.\n",
+          this, aHttpTransaction));
+    stream = new Http3WebTransportSession(aHttpTransaction, this);
+    mHasWebTransportSession = true;
+  } else {
+    LOG3(("Http3Session::AddStream %p atrans=%p.\n", this, aHttpTransaction));
+    stream = new Http3Stream(aHttpTransaction, this, cos, mCurrentBrowserId);
+  }
+
+  mStreamTransactionHash.InsertOrUpdate(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);
+      }
+      if ((mWebTransportNegotiationStatus ==
+           WebTransportNegotiation::NEGOTIATING) &&
+          (trans && trans->IsForWebTransport())) {
+        LOG(("waiting for negotiation"));
+        mWaitingForWebTransportNegotiation.AppendElement(stream);
+      }
+      return true;
+    }
+    m0RTTStreams.AppendElement(stream);
+  }
+
+  if ((mWebTransportNegotiationStatus ==
+       WebTransportNegotiation::NEGOTIATING) &&
+      (trans && trans->IsForWebTransport())) {
+    LOG(("waiting for negotiation"));
+    mWaitingForWebTransportNegotiation.AppendElement(stream);
+    return true;
+  }
+
+  if (!mFirstHttpTransaction && !IsConnected()) {
+    mFirstHttpTransaction = aHttpTransaction->QueryHttpTransaction();
+    LOG3(("Http3Session::AddStream first session=%p trans=%p ", this,
+          mFirstHttpTransaction.get()));
+  }
+  StreamReadyToWrite(stream);
+
+  return true;
+}
+
+bool Http3Session::CanReuse() {
+  // TODO: we assume "pooling" is disabled here, so we don't allow this session
+  // to be reused. "pooling" will be implemented in bug 1815735.
+  return CanSandData() && !(mGoawayReceived || mShouldClose) &&
+         !mHasWebTransportSession;
+}
+
+void Http3Session::QueueStream(Http3StreamBase* 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");
+
+  RefPtr<Http3StreamBase> stream;
+  while ((stream = mQueuedStreams.PopFront())) {
+    LOG3(("Http3Session::ProcessPending %p stream %p woken from queue.", this,
+          stream.get()));
+    MOZ_ASSERT(stream->Queued());
+    stream->SetQueued(false);
+    mReadyForWrite.Push(stream);
+  }
+  MaybeResumeSend();
+}
+
+static void RemoveStreamFromQueue(Http3StreamBase* aStream,
+                                  nsRefPtrDeque<Http3StreamBase>& queue) {
+  size_t size = queue.GetSize();
+  for (size_t count = 0; count < size; ++count) {
+    RefPtr<Http3StreamBase> stream = queue.PopFront();
+    if (stream != aStream) {
+      queue.Push(stream);
+    }
+  }
+}
+
+void Http3Session::RemoveStreamFromQueues(Http3StreamBase* 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, Http3StreamBase* 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 = NS_OK;
+  RefPtr<Http3Stream> httpStream = aStream->GetHttp3Stream();
+  if (httpStream) {
+    rv = mHttp3Connection->Fetch(
+        aMethod, aScheme, aAuthorityHeader, aPath, aHeaders, aStreamId,
+        httpStream->PriorityUrgency(), httpStream->PriorityIncremental());
+  } else {
+    MOZ_RELEASE_ASSERT(aStream->GetHttp3WebTransportSession(),
+                       "It must be a WebTransport session");
+    // Don't call CreateWebTransport if we are still waiting for the negotiation
+    // result.
+    if (mWebTransportNegotiationStatus ==
+        WebTransportNegotiation::NEGOTIATING) {
+      if (!mWaitingForWebTransportNegotiation.Contains(aStream)) {
+        mWaitingForWebTransportNegotiation.AppendElement(aStream);
+      }
+      return NS_BASE_STREAM_WOULD_BLOCK;
+    }
+    rv = mHttp3Connection->CreateWebTransport(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()) {
+    MOZ_ASSERT(mConnectionIdleStart);
+    MOZ_ASSERT(mFirstStreamIdReuseIdleConnection.isNothing());
+
+    mConnectionIdleEnd = TimeStamp::Now();
+    mFirstStreamIdReuseIdleConnection = Some(*aStreamId);
+  }
+  mStreamIdHash.InsertOrUpdate(*aStreamId, RefPtr{aStream});
+  mTransactionCount++;
+
+  return NS_OK;
+}
+
+// This is called by Http3WebTransportStream::OnReadSegment.
+// TODO: this function is almost the same as TryActivating().
+// We should try to reduce the duplicate code.
+nsresult Http3Session::TryActivatingWebTransportStream(
+    uint64_t* aStreamId, Http3StreamBase* aStream) {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+  MOZ_ASSERT(*aStreamId == UINT64_MAX);
+
+  LOG(
+      ("Http3Session::TryActivatingWebTransportStream [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::TryActivatingWebTransportStream %p stream=%p already "
+         "queued.\n",
+         this, aStream));
+    return NS_BASE_STREAM_WOULD_BLOCK;
+  }
+
+  nsresult rv = NS_OK;
+  RefPtr<Http3WebTransportStream> wtStream =
+      aStream->GetHttp3WebTransportStream();
+  MOZ_RELEASE_ASSERT(wtStream, "It must be a WebTransport stream");
+  rv = mHttp3Connection->CreateWebTransportStream(
+      wtStream->SessionId(), wtStream->StreamType(), aStreamId);
+
+  if (NS_FAILED(rv)) {
+    LOG((
+        "Http3Session::TryActivatingWebTransportStream returns error=0x%" PRIx32
+        "[stream=%p, "
+        "this=%p]",
+        static_cast<uint32_t>(rv), aStream, this));
+    if (rv == NS_BASE_STREAM_WOULD_BLOCK) {
+      LOG3(
+          ("Http3Session::TryActivatingWebTransportStream %p stream=%p no room "
+           "for more "
+           "concurrent streams\n",
+           this, aStream));
+      QueueStream(aStream);
+      return rv;
+    }
+
+    return rv;
+  }
+
+  LOG(("Http3Session::TryActivatingWebTransportStream streamId=0x%" PRIx64
+       " for stream=%p [this=%p].",
+       *aStreamId, aStream, this));
+
+  MOZ_ASSERT(*aStreamId != UINT64_MAX);
+
+  RefPtr<Http3StreamBase> session = mStreamIdHash.Get(wtStream->SessionId());
+  MOZ_ASSERT(session);
+  Http3WebTransportSession* wtSession = session->GetHttp3WebTransportSession();
+  MOZ_ASSERT(wtSession);
+
+  wtSession->RemoveWebTransportStream(wtStream);
+
+  // WebTransportStream is managed by Http3Session now.
+  mWebTransportStreams.AppendElement(wtStream);
+  mWebTransportStreamToSessionMap.InsertOrUpdate(*aStreamId,
+                                                 session->StreamId());
+  mStreamIdHash.InsertOrUpdate(*aStreamId, std::move(wtStream));
+  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::ResetOrStopSendingRecvd(uint64_t aStreamId, uint64_t aError,
+                                           ResetType aType) {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+
+  uint64_t sessionId = 0;
+  if (mWebTransportStreamToSessionMap.Get(aStreamId, &sessionId)) {
+    uint8_t wtError = Http3ErrorToWebTransportError(aError);
+    nsresult rv = GetNSResultFromWebTransportError(wtError);
+
+    RefPtr<Http3StreamBase> stream = mStreamIdHash.Get(aStreamId);
+    if (stream) {
+      if (aType == RESET) {
+        stream->SetRecvdReset();
+      }
+      RefPtr<Http3WebTransportStream> wtStream =
+          stream->GetHttp3WebTransportStream();
+      if (wtStream) {
+        CloseWebTransportStream(wtStream, rv);
+      }
+    }
+
+    RefPtr<Http3StreamBase> session = mStreamIdHash.Get(sessionId);
+    if (session) {
+      Http3WebTransportSession* wtSession =
+          session->GetHttp3WebTransportSession();
+      MOZ_ASSERT(wtSession);
+      if (wtSession) {
+        if (aType == RESET) {
+          wtSession->OnStreamReset(aStreamId, rv);
+        } else {
+          wtSession->OnStreamStopSending(aStreamId, rv);
+        }
+      }
+    }
+    return;
+  }
+
+  RefPtr<Http3StreamBase> stream = mStreamIdHash.Get(aStreamId);
+  if (!stream) {
+    return;
+  }
+
+  RefPtr<Http3Stream> httpStream = stream->GetHttp3Stream();
+  if (!httpStream) {
+    return;
+  }
+
+  // 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.
+    httpStream->Transaction()->DisableHttp3(false);
+    httpStream->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.
+    httpStream->Transaction()->DoNotRemoveAltSvc();
+    CloseStream(stream, NS_ERROR_NET_RESET);
+  } else {
+    if (httpStream->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) {
+  MOZ_ASSERT(false, "Http3Session::ReadSegments()");
+  return NS_ERROR_UNEXPECTED;
+}
+
+nsresult Http3Session::SendData(nsIUDPSocket* socket) {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+
+  LOG(("Http3Session::SendData [this=%p]", this));
+
+  //   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;
+  RefPtr<Http3StreamBase> stream;
+
+  // Step 1)
+  while (CanSandData() && (stream = mReadyForWrite.PopFront())) {
+    LOG(("Http3Session::SendData call ReadSegments from stream=%p [this=%p]",
+         stream.get(), this));
+
+    rv = stream->ReadSegments();
+
+    // on stream error we return earlier to let the error be handled.
+    if (NS_FAILED(rv)) {
+      LOG3(("Http3Session::SendData %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::SendData %p soft error override\n", this));
+        rv = NS_OK;
+      } else {
+        break;
+      }
+    }
+  }
+
+  if (NS_SUCCEEDED(rv)) {
+    // Step 2:
+    // Call actuall network write.
+    rv = ProcessOutput(socket);
+  }
+
+  // Step 3:
+  MaybeResumeSend();
+
+  if (rv == NS_BASE_STREAM_WOULD_BLOCK) {
+    rv = NS_OK;
+  }
+
+  return rv;
+}
+
+void Http3Session::StreamReadyToWrite(Http3StreamBase* 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<Http3StreamBase> slowConsumer =
+      mSlowConsumersReadyForRead.ElementAt(0);
+  mSlowConsumersReadyForRead.RemoveElementAt(0);
+
+  nsresult rv = ProcessTransactionRead(slowConsumer);
+
+  return rv;
+}
+
+nsresult Http3Session::WriteSegments(nsAHttpSegmentWriter* writer,
+                                     uint32_t count, uint32_t* countWritten) {
+  MOZ_ASSERT(false, "Http3Session::WriteSegments()");
+  return NS_ERROR_UNEXPECTED;
+}
+
+nsresult Http3Session::RecvData(nsIUDPSocket* socket) {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+
+  // 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;
+  }
+
+  ProcessInput(socket);
+
+  rv = ProcessEvents();
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  rv = ProcessOutput(socket);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+const uint32_t HTTP3_TELEMETRY_APP_NECKO = 42;
+
+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 the "closing" key and the
+    // value HTTP3_TELEMETRY_APP_NECKO.
+    Telemetry::Accumulate(Telemetry::HTTP3_CONNECTION_CLOSE_CODE_3,
+                          "app_closing"_ns, HTTP3_TELEMETRY_APP_NECKO);
+    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();
+    }
+    mTimer = nullptr;
+    mConnection = nullptr;
+    mUdpConn = 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;
+  }
+
+  if (mState == ZERORTT) {
+    ZeroRttTelemetry(aCallNeqoClose ? ZeroRttOutcome::USED_CONN_CLOSED_BY_NECKO
+                                    : ZeroRttOutcome::USED_CONN_ERROR);
+  }
+
+  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<Http3StreamBase> 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(Http3StreamBase* aStream, nsresult aResult) {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+  RefPtr<Http3WebTransportStream> wtStream =
+      aStream->GetHttp3WebTransportStream();
+  if (wtStream) {
+    CloseWebTransportStream(wtStream, aResult);
+    return;
+  }
+
+  RefPtr<Http3Stream> httpStream = aStream->GetHttp3Stream();
+  if (httpStream && !httpStream->RecvdFin() && !httpStream->RecvdReset() &&
+      httpStream->HasStreamId()) {
+    mHttp3Connection->CancelFetch(httpStream->StreamId(),
+                                  HTTP3_APP_ERROR_REQUEST_CANCELLED);
+  }
+
+  aStream->Close(aResult);
+  CloseStreamInternal(aStream, aResult);
+}
+
+void Http3Session::CloseStreamInternal(Http3StreamBase* aStream,
+                                       nsresult aResult) {
+  LOG3(("Http3Session::CloseStreamInternal %p %p 0x%" PRIx32, this, aStream,
+        static_cast<uint32_t>(aResult)));
+  if (aStream->HasStreamId()) {
+    // We know the transaction reusing an idle connection has succeeded or
+    // failed.
+    if (mFirstStreamIdReuseIdleConnection.isSome() &&
+        aStream->StreamId() == *mFirstStreamIdReuseIdleConnection) {
+      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);
+  if (nsAHttpTransaction* transaction = aStream->Transaction()) {
+    mStreamTransactionHash.Remove(transaction);
+  }
+  mWebTransportSessions.RemoveElement(aStream);
+  mWebTransportStreams.RemoveElement(aStream);
+  // Close(NS_OK) implies that the NeqoHttp3Conn will be closed, so we can only
+  // do this when there is no Http3Steeam, WebTransportSession and
+  // WebTransportStream.
+  if ((mShouldClose || mGoawayReceived) &&
+      (!mStreamTransactionHash.Count() && mWebTransportSessions.IsEmpty() &&
+       mWebTransportStreams.IsEmpty())) {
+    MOZ_ASSERT(!IsClosing());
+    Close(NS_OK);
+  }
+}
+
+void Http3Session::CloseWebTransportStream(Http3WebTransportStream* aStream,
+                                           nsresult aResult) {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+  LOG3(("Http3Session::CloseWebTransportStream %p %p 0x%" PRIx32, this, aStream,
+        static_cast<uint32_t>(aResult)));
+  if (aStream && !aStream->RecvdFin() && !aStream->RecvdReset() &&
+      (aStream->HasStreamId())) {
+    mHttp3Connection->ResetStream(aStream->StreamId(),
+                                  HTTP3_APP_ERROR_REQUEST_CANCELLED);
+  }
+
+  aStream->Close(aResult);
+  CloseStreamInternal(aStream, aResult);
+}
+
+void Http3Session::ResetWebTransportStream(Http3WebTransportStream* aStream,
+                                           uint64_t aErrorCode) {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+  LOG3(("Http3Session::ResetWebTransportStream %p %p 0x%" PRIx64, this, aStream,
+        aErrorCode));
+  mHttp3Connection->ResetStream(aStream->StreamId(), aErrorCode);
+}
+
+void Http3Session::StreamStopSending(Http3WebTransportStream* aStream,
+                                     uint8_t aErrorCode) {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+  LOG(("Http3Session::StreamStopSending %p %p 0x%" PRIx32, this, aStream,
+       static_cast<uint32_t>(aErrorCode)));
+  mHttp3Connection->StreamStopSending(aStream->StreamId(), aErrorCode);
+}
+
+nsresult Http3Session::TakeTransport(nsISocketTransport**,
+                                     nsIAsyncInputStream**,
+                                     nsIAsyncOutputStream**) {
+  MOZ_ASSERT(false, "TakeTransport of Http3Session");
+  return NS_ERROR_UNEXPECTED;
+}
+
+Http3WebTransportSession* Http3Session::GetWebTransportSession(
+    nsAHttpTransaction* aTransaction) {
+  RefPtr<Http3StreamBase> stream = mStreamTransactionHash.Get(aTransaction);
+
+  if (!stream || !stream->GetHttp3WebTransportSession()) {
+    MOZ_ASSERT(false, "There must be a stream");
+    return nullptr;
+  }
+  RemoveStreamFromQueues(stream);
+  mStreamTransactionHash.Remove(aTransaction);
+  mWebTransportSessions.AppendElement(stream);
+  return stream->GetHttp3WebTransportSession();
+}
+
+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::CloseWebTransportConn() {
+  LOG3(("Http3Session::CloseWebTransportConn %p\n", this));
+  // We need to dispatch, since Http3Session could be released in
+  // HttpConnectionUDP::CloseTransaction.
+  gSocketTransportService->Dispatch(
+      NS_NewRunnableFunction("Http3Session::CloseWebTransportConn",
+                             [self = RefPtr{this}]() {
+                               if (self->mUdpConn) {
+                                 self->mUdpConn->CloseTransaction(
+                                     self, NS_ERROR_ABORT);
+                               }
+                             }),
+      NS_DISPATCH_NORMAL);
+}
+
+void Http3Session::CurrentBrowserIdChanged(uint64_t id) {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+
+  mCurrentBrowserId = id;
+
+  for (const auto& stream : mStreamTransactionHash.Values()) {
+    RefPtr<Http3Stream> httpStream = stream->GetHttp3Stream();
+    if (httpStream) {
+      httpStream->CurrentBrowserIdChanged(id);
+    }
+  }
+}
+
+// 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<Http3StreamBase> 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()));
+
+  StreamHasDataToWrite(stream);
+}
+
+void Http3Session::StreamHasDataToWrite(Http3StreamBase* aStream) {
+  if (!IsClosing()) {
+    StreamReadyToWrite(aStream);
+  } 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<Http3StreamBase> 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(Http3StreamBase* 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<nsITLSSocketControl> sslSocketControl;
+  mConnection->GetTLSSocketControl(getter_AddRefs(sslSocketControl));
+  if (!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.InsertOrUpdate(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.InsertOrUpdate(key2, joinedReturn);
+    }
+  }
+  return joinedReturn;
+}
+
+void Http3Session::CallCertVerification(Maybe<nsCString> aEchPublicName) {
+  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));
+  }
+
+  uint32_t providerFlags;
+  // the return value is always NS_OK, just ignore it.
+  Unused << mSocketControl->GetProviderFlags(&providerFlags);
+
+  nsCString echConfig;
+  nsresult nsrv = mSocketControl->GetEchConfig(echConfig);
+  bool verifyToEchPublicName = NS_SUCCEEDED(nsrv) && !echConfig.IsEmpty() &&
+                               aEchPublicName && !aEchPublicName->IsEmpty();
+  const nsACString& hostname =
+      verifyToEchPublicName ? *aEchPublicName : mSocketControl->GetHostName();
+
+  SECStatus rv = psm::AuthCertificateHookWithInfo(
+      mSocketControl, hostname, 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",
+                          mUdpConn, &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->SetNegotiatedNPN(secInfo.alpn);
+
+    mSocketControl->SetInfo(secInfo.cipher, secInfo.version, secInfo.group,
+                            secInfo.signature_scheme, secInfo.ech_accepted);
+    mHandshakeSucceeded = true;
+  }
+
+  if (!mSocketControl->HasServerCert()) {
+    mSocketControl->RebuildCertificateInfoFromSSLTokenCache();
+  }
+}
+
+// Transport error have values from 0x0 to 0x11.
+// (https://tools.ietf.org/html/draft-ietf-quic-transport-34#section-20.1)
+// We will map this error to 0-16.
+// 17 will capture error codes between and including 0x12 and 0x0ff. This
+// error codes are not define by the spec but who know peer may sent them.
+// CryptoAlerts have value 0x100 + alert code. The range of alert code is
+// 0x00-0xff. (https://tools.ietf.org/html/draft-ietf-quic-tls_34#section-4.8)
+// Since telemetry does not allow more than 100 bucket, we use three diffrent
+// keys to map all alert codes.
+const uint32_t HTTP3_TELEMETRY_TRANSPORT_END = 16;
+const uint32_t HTTP3_TELEMETRY_TRANSPORT_UNKNOWN = 17;
+const uint32_t HTTP3_TELEMETRY_TRANSPORT_CRYPTO_UNKNOWN = 18;
+// All errors from CloseError::Tag::CryptoError will be map to 19
+const uint32_t HTTP3_TELEMETRY_CRYPTO_ERROR = 19;
+
+uint64_t GetCryptoAlertCode(nsCString& key, uint64_t error) {
+  if (error < 100) {
+    key.Append("_a"_ns);
+    return error;
+  }
+  if (error < 200) {
+    error -= 100;
+    key.Append("_b"_ns);
+    return error;
+  }
+  if (error < 256) {
+    error -= 200;
+    key.Append("_c"_ns);
+    return error;
+  }
+  return HTTP3_TELEMETRY_TRANSPORT_CRYPTO_UNKNOWN;
+}
+
+uint64_t GetTransportErrorCodeForTelemetry(nsCString& key, uint64_t error) {
+  if (error <= HTTP3_TELEMETRY_TRANSPORT_END) {
+    return error;
+  }
+  if (error < 0x100) {
+    return HTTP3_TELEMETRY_TRANSPORT_UNKNOWN;
+  }
+
+  return GetCryptoAlertCode(key, error - 0x100);
+}
+
+// Http3 error codes are 0x100-0x110.
+// (https://tools.ietf.org/html/draft-ietf-quic-http-33#section-8.1)
+// The mapping is described below.
+// 0x00-0x10 mapped to 0-16
+// 0x11-0xff mapped to 17
+// 0x100-0x110 mapped to 18-36
+// 0x111-0x1ff mapped to 37
+// 0x200-0x202 mapped to 38-40
+// Others mapped to 41
+const uint32_t HTTP3_TELEMETRY_APP_UNKNOWN_1 = 17;
+const uint32_t HTTP3_TELEMETRY_APP_START = 18;
+// Values between 0x111 and 0x1ff are no definded and will be map to 18.
+const uint32_t HTTP3_TELEMETRY_APP_UNKNOWN_2 = 37;
+// Error codes between 0x200 and 0x202 are related to qpack.
+// (https://tools.ietf.org/html/draft-ietf-quic-qpack-20#section-6)
+// They will be mapped to 19-21
+const uint32_t HTTP3_TELEMETRY_APP_QPACK_START = 38;
+// Values greater or equal to 0x203 are no definded and will be map to 41.
+const uint32_t HTTP3_TELEMETRY_APP_UNKNOWN_3 = 41;
+
+uint64_t GetAppErrorCodeForTelemetry(uint64_t error) {
+  if (error <= 0x10) {
+    return error;
+  }
+  if (error <= 0xff) {
+    return HTTP3_TELEMETRY_APP_UNKNOWN_1;
+  }
+  if (error <= 0x110) {
+    return error - 0x100 + HTTP3_TELEMETRY_APP_START;
+  }
+  if (error < 0x200) {
+    return HTTP3_TELEMETRY_APP_UNKNOWN_2;
+  }
+  if (error <= 0x202) {
+    return error - 0x200 + HTTP3_TELEMETRY_APP_QPACK_START;
+  }
+  return HTTP3_TELEMETRY_APP_UNKNOWN_3;
+}
+
+void Http3Session::CloseConnectionTelemetry(CloseError& aError, bool aClosing) {
+  uint64_t value = 0;
+  nsCString key = EmptyCString();
+
+  switch (aError.tag) {
+    case CloseError::Tag::TransportInternalError:
+      key = "transport_internal"_ns;
+      value = aError.transport_internal_error._0;
+      break;
+    case CloseError::Tag::TransportInternalErrorOther:
+      key = "transport_other"_ns;
+      value = aError.transport_internal_error_other._0;
+      break;
+    case CloseError::Tag::TransportError:
+      key = "transport"_ns;
+      value = GetTransportErrorCodeForTelemetry(key, aError.transport_error._0);
+      break;
+    case CloseError::Tag::CryptoError:
+      key = "transport"_ns;
+      value = HTTP3_TELEMETRY_CRYPTO_ERROR;
+      break;
+    case CloseError::Tag::CryptoAlert:
+      key = "transport_crypto_alert"_ns;
+      value = GetCryptoAlertCode(key, aError.crypto_alert._0);
+      break;
+    case CloseError::Tag::PeerAppError:
+      key = "peer_app"_ns;
+      value = GetAppErrorCodeForTelemetry(aError.peer_app_error._0);
+      break;
+    case CloseError::Tag::PeerError:
+      key = "peer_transport"_ns;
+      value = GetTransportErrorCodeForTelemetry(key, aError.peer_error._0);
+      break;
+    case CloseError::Tag::AppError:
+      key = "app"_ns;
+      value = GetAppErrorCodeForTelemetry(aError.app_error._0);
+      break;
+    case CloseError::Tag::EchRetry:
+      key = "transport_crypto_alert"_ns;
+      value = 121;
+  }
+
+  key.Append(aClosing ? "_closing"_ns : "_closed"_ns);
+
+  Telemetry::Accumulate(Telemetry::HTTP3_CONNECTION_CLOSE_CODE_3, key, 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(mUdpConn);
+    MaybeResumeSend();
+  }
+}
+
+void Http3Session::EchOutcomeTelemetry() {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+
+  nsAutoCString key;
+  switch (mEchExtensionStatus) {
+    case EchExtensionStatus::kNotPresent:
+      key = "NONE";
+      break;
+    case EchExtensionStatus::kGREASE:
+      key = "GREASE";
+      break;
+    case EchExtensionStatus::kReal:
+      key = "REAL";
+      break;
+  }
+
+  Telemetry::Accumulate(Telemetry::HTTP3_ECH_OUTCOME, key,
+                        mHandshakeSucceeded ? 0 : 1);
+}
+
+void Http3Session::ZeroRttTelemetry(ZeroRttOutcome aOutcome) {
+  Telemetry::Accumulate(Telemetry::HTTP3_0RTT_STATE, aOutcome);
+
+  nsAutoCString key;
+
+  switch (aOutcome) {
+    case USED_SUCCEEDED:
+      key = "succeeded"_ns;
+      break;
+    case USED_REJECTED:
+      key = "rejected"_ns;
+      break;
+    case USED_CONN_ERROR:
+      key = "conn_error"_ns;
+      break;
+    case USED_CONN_CLOSED_BY_NECKO:
+      key = "conn_closed_by_necko"_ns;
+      break;
+    default:
+      break;
+  }
+
+  if (!key.IsEmpty()) {
+    MOZ_ASSERT(mZeroRttStarted);
+    Telemetry::AccumulateTimeDelta(Telemetry::HTTP3_0RTT_STATE_DURATION, key,
+                                   mZeroRttStarted, TimeStamp::Now());
+  }
+}
+
+nsresult Http3Session::GetTransactionTLSSocketControl(
+    nsITLSSocketControl** tlsSocketControl) {
+  NS_IF_ADDREF(*tlsSocketControl = mSocketControl);
+  return NS_OK;
+}
+
+PRIntervalTime Http3Session::LastWriteTime() { return mLastWriteTime; }
+
+void Http3Session::WebTransportNegotiationDone() {
+  for (size_t i = 0; i < mWaitingForWebTransportNegotiation.Length(); ++i) {
+    if (mWaitingForWebTransportNegotiation[i]) {
+      mReadyForWrite.Push(mWaitingForWebTransportNegotiation[i]);
+    }
+  }
+  mWaitingForWebTransportNegotiation.Clear();
+  MaybeResumeSend();
+}
+
+//=========================================================================
+// WebTransport
+//=========================================================================
+
+nsresult Http3Session::CloseWebTransport(uint64_t aSessionId, uint32_t aError,
+                                         const nsACString& aMessage) {
+  return mHttp3Connection->CloseWebTransport(aSessionId, aError, aMessage);
+}
+
+nsresult Http3Session::CreateWebTransportStream(
+    uint64_t aSessionId, WebTransportStreamType aStreamType,
+    uint64_t* aStreamId) {
+  return mHttp3Connection->CreateWebTransportStream(aSessionId, aStreamType,
+                                                    aStreamId);
+}
+
+void Http3Session::SendDatagram(Http3WebTransportSession* aSession,
+                                nsTArray<uint8_t>& aData,
+                                uint64_t aTrackingId) {
+  nsresult rv = mHttp3Connection->WebTransportSendDatagram(aSession->StreamId(),
+                                                           aData, aTrackingId);
+  LOG(("Http3Session::SendDatagram %p res=%" PRIx32, this,
+       static_cast<uint32_t>(rv)));
+  if (!aTrackingId) {
+    return;
+  }
+
+  switch (rv) {
+    case NS_OK:
+      aSession->OnOutgoingDatagramOutCome(
+          aTrackingId, WebTransportSessionEventListener::DatagramOutcome::SENT);
+      break;
+    case NS_ERROR_NOT_AVAILABLE:
+      aSession->OnOutgoingDatagramOutCome(
+          aTrackingId, WebTransportSessionEventListener::DatagramOutcome::
+                           DROPPED_TOO_MUCH_DATA);
+      break;
+    default:
+      aSession->OnOutgoingDatagramOutCome(
+          aTrackingId,
+          WebTransportSessionEventListener::DatagramOutcome::UNKNOWN);
+      break;
+  }
+}
+
+uint64_t Http3Session::MaxDatagramSize(uint64_t aSessionId) {
+  uint64_t size = 0;
+  Unused << mHttp3Connection->WebTransportMaxDatagramSize(aSessionId, &size);
+  return size;
+}
+
+}  // namespace mozilla::net