Adding upstream version 124.0.1.upstream/124.0.1

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

1 files changed, 3411 insertions, 0 deletions

diff --git a/netwerk/base/nsSocketTransport2.cpp b/netwerk/base/nsSocketTransport2.cpp
new file mode 100644
index 0000000000..e12a376788
--- /dev/null
+++ b/netwerk/base/nsSocketTransport2.cpp
@@ -0,0 +1,3411 @@
+/* -*- 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 <algorithm>
+
+#include "nsSocketTransport2.h"
+
+#include "IOActivityMonitor.h"
+#include "NSSErrorsService.h"
+#include "NetworkDataCountLayer.h"
+#include "QuicSocketControl.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/StaticPrefs_network.h"
+#include "mozilla/SyncRunnable.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/dom/ToJSValue.h"
+#include "mozilla/net/NeckoChild.h"
+#include "mozilla/net/SSLTokensCache.h"
+#include "mozilla/ProfilerBandwidthCounter.h"
+#include "nsCOMPtr.h"
+#include "nsICancelable.h"
+#include "nsIClassInfoImpl.h"
+#include "nsIDNSByTypeRecord.h"
+#include "nsIDNSRecord.h"
+#include "nsIDNSService.h"
+#include "nsIOService.h"
+#include "nsIPipe.h"
+#include "nsISocketProvider.h"
+#include "nsITLSSocketControl.h"
+#include "nsNetAddr.h"
+#include "nsNetCID.h"
+#include "nsNetSegmentUtils.h"
+#include "nsNetUtil.h"
+#include "nsPrintfCString.h"
+#include "nsProxyInfo.h"
+#include "nsSocketProviderService.h"
+#include "nsStreamUtils.h"
+#include "nsThreadUtils.h"
+#include "nsTransportUtils.h"
+#include "nsURLHelper.h"
+#include "prerr.h"
+#include "sslexp.h"
+#include "xpcpublic.h"
+
+#if defined(FUZZING)
+#  include "FuzzyLayer.h"
+#  include "FuzzySocketControl.h"
+#  include "mozilla/StaticPrefs_fuzzing.h"
+#endif
+
+#if defined(XP_WIN)
+#  include "ShutdownLayer.h"
+#endif
+
+/* Following inclusions required for keepalive config not supported by NSPR. */
+#include "private/pprio.h"
+#if defined(XP_WIN)
+#  include <winsock2.h>
+#  include <mstcpip.h>
+#elif defined(XP_UNIX)
+#  include <errno.h>
+#  include <netinet/tcp.h>
+#endif
+/* End keepalive config inclusions. */
+
+#define SUCCESSFUL_CONNECTING_TO_IPV4_ADDRESS 0
+#define UNSUCCESSFUL_CONNECTING_TO_IPV4_ADDRESS 1
+#define SUCCESSFUL_CONNECTING_TO_IPV6_ADDRESS 2
+#define UNSUCCESSFUL_CONNECTING_TO_IPV6_ADDRESS 3
+
+//-----------------------------------------------------------------------------
+
+static NS_DEFINE_CID(kDNSServiceCID, NS_DNSSERVICE_CID);
+
+//-----------------------------------------------------------------------------
+
+namespace mozilla {
+namespace net {
+
+class nsSocketEvent : public Runnable {
+ public:
+  nsSocketEvent(nsSocketTransport* transport, uint32_t type,
+                nsresult status = NS_OK, nsISupports* param = nullptr,
+                std::function<void()>&& task = nullptr)
+      : Runnable("net::nsSocketEvent"),
+        mTransport(transport),
+        mType(type),
+        mStatus(status),
+        mParam(param),
+        mTask(std::move(task)) {}
+
+  NS_IMETHOD Run() override {
+    mTransport->OnSocketEvent(mType, mStatus, mParam, std::move(mTask));
+    return NS_OK;
+  }
+
+ private:
+  RefPtr<nsSocketTransport> mTransport;
+
+  uint32_t mType;
+  nsresult mStatus;
+  nsCOMPtr<nsISupports> mParam;
+  std::function<void()> mTask;
+};
+
+//-----------------------------------------------------------------------------
+
+// #define TEST_CONNECT_ERRORS
+#ifdef TEST_CONNECT_ERRORS
+#  include <stdlib.h>
+static PRErrorCode RandomizeConnectError(PRErrorCode code) {
+  //
+  // To test out these errors, load http://www.yahoo.com/.  It should load
+  // correctly despite the random occurrence of these errors.
+  //
+  int n = rand();
+  if (n > RAND_MAX / 2) {
+    struct {
+      PRErrorCode err_code;
+      const char* err_name;
+    } errors[] = {
+        //
+        // These errors should be recoverable provided there is another
+        // IP address in mDNSRecord.
+        //
+        {PR_CONNECT_REFUSED_ERROR, "PR_CONNECT_REFUSED_ERROR"},
+        {PR_CONNECT_TIMEOUT_ERROR, "PR_CONNECT_TIMEOUT_ERROR"},
+        //
+        // This error will cause this socket transport to error out;
+        // however, if the consumer is HTTP, then the HTTP transaction
+        // should be restarted when this error occurs.
+        //
+        {PR_CONNECT_RESET_ERROR, "PR_CONNECT_RESET_ERROR"},
+    };
+    n = n % (sizeof(errors) / sizeof(errors[0]));
+    code = errors[n].err_code;
+    SOCKET_LOG(("simulating NSPR error %d [%s]\n", code, errors[n].err_name));
+  }
+  return code;
+}
+#endif
+
+//-----------------------------------------------------------------------------
+
+nsresult ErrorAccordingToNSPR(PRErrorCode errorCode) {
+  nsresult rv = NS_ERROR_FAILURE;
+  switch (errorCode) {
+    case PR_WOULD_BLOCK_ERROR:
+      rv = NS_BASE_STREAM_WOULD_BLOCK;
+      break;
+    case PR_CONNECT_ABORTED_ERROR:
+    case PR_CONNECT_RESET_ERROR:
+      rv = NS_ERROR_NET_RESET;
+      break;
+    case PR_END_OF_FILE_ERROR:  // XXX document this correlation
+      rv = NS_ERROR_NET_INTERRUPT;
+      break;
+    case PR_CONNECT_REFUSED_ERROR:
+    // We lump the following NSPR codes in with PR_CONNECT_REFUSED_ERROR. We
+    // could get better diagnostics by adding distinct XPCOM error codes for
+    // each of these, but there are a lot of places in Gecko that check
+    // specifically for NS_ERROR_CONNECTION_REFUSED, all of which would need to
+    // be checked.
+    case PR_NETWORK_UNREACHABLE_ERROR:
+    case PR_HOST_UNREACHABLE_ERROR:
+    case PR_ADDRESS_NOT_AVAILABLE_ERROR:
+    // Treat EACCES as a soft error since (at least on Linux) connect() returns
+    // EACCES when an IPv6 connection is blocked by a firewall. See bug 270784.
+    case PR_NO_ACCESS_RIGHTS_ERROR:
+      rv = NS_ERROR_CONNECTION_REFUSED;
+      break;
+    case PR_ADDRESS_NOT_SUPPORTED_ERROR:
+      rv = NS_ERROR_SOCKET_ADDRESS_NOT_SUPPORTED;
+      break;
+    case PR_IO_TIMEOUT_ERROR:
+    case PR_CONNECT_TIMEOUT_ERROR:
+      rv = NS_ERROR_NET_TIMEOUT;
+      break;
+    case PR_OUT_OF_MEMORY_ERROR:
+    // These really indicate that the descriptor table filled up, or that the
+    // kernel ran out of network buffers - but nobody really cares which part of
+    // the system ran out of memory.
+    case PR_PROC_DESC_TABLE_FULL_ERROR:
+    case PR_SYS_DESC_TABLE_FULL_ERROR:
+    case PR_INSUFFICIENT_RESOURCES_ERROR:
+      rv = NS_ERROR_OUT_OF_MEMORY;
+      break;
+    case PR_ADDRESS_IN_USE_ERROR:
+      rv = NS_ERROR_SOCKET_ADDRESS_IN_USE;
+      break;
+    // These filename-related errors can arise when using Unix-domain sockets.
+    case PR_FILE_NOT_FOUND_ERROR:
+      rv = NS_ERROR_FILE_NOT_FOUND;
+      break;
+    case PR_IS_DIRECTORY_ERROR:
+      rv = NS_ERROR_FILE_IS_DIRECTORY;
+      break;
+    case PR_LOOP_ERROR:
+      rv = NS_ERROR_FILE_UNRESOLVABLE_SYMLINK;
+      break;
+    case PR_NAME_TOO_LONG_ERROR:
+      rv = NS_ERROR_FILE_NAME_TOO_LONG;
+      break;
+    case PR_NO_DEVICE_SPACE_ERROR:
+      rv = NS_ERROR_FILE_NO_DEVICE_SPACE;
+      break;
+    case PR_NOT_DIRECTORY_ERROR:
+      rv = NS_ERROR_FILE_NOT_DIRECTORY;
+      break;
+    case PR_READ_ONLY_FILESYSTEM_ERROR:
+      rv = NS_ERROR_FILE_READ_ONLY;
+      break;
+    case PR_BAD_ADDRESS_ERROR:
+      rv = NS_ERROR_UNKNOWN_HOST;
+      break;
+    default:
+      if (psm::IsNSSErrorCode(errorCode)) {
+        rv = psm::GetXPCOMFromNSSError(errorCode);
+      }
+      break;
+
+      // NSPR's socket code can return these, but they're not worth breaking out
+      // into their own error codes, distinct from NS_ERROR_FAILURE:
+      //
+      // PR_BAD_DESCRIPTOR_ERROR
+      // PR_INVALID_ARGUMENT_ERROR
+      // PR_NOT_SOCKET_ERROR
+      // PR_NOT_TCP_SOCKET_ERROR
+      //   These would indicate a bug internal to the component.
+      //
+      // PR_PROTOCOL_NOT_SUPPORTED_ERROR
+      //   This means that we can't use the given "protocol" (like
+      //   IPPROTO_TCP or IPPROTO_UDP) with a socket of the given type. As
+      //   above, this indicates an internal bug.
+      //
+      // PR_IS_CONNECTED_ERROR
+      //   This indicates that we've applied a system call like 'bind' or
+      //   'connect' to a socket that is already connected. The socket
+      //   components manage each file descriptor's state, and in some cases
+      //   handle this error result internally. We shouldn't be returning
+      //   this to our callers.
+      //
+      // PR_IO_ERROR
+      //   This is so vague that NS_ERROR_FAILURE is just as good.
+  }
+  SOCKET_LOG(("ErrorAccordingToNSPR [in=%d out=%" PRIx32 "]\n", errorCode,
+              static_cast<uint32_t>(rv)));
+  return rv;
+}
+
+//-----------------------------------------------------------------------------
+// socket input stream impl
+//-----------------------------------------------------------------------------
+
+nsSocketInputStream::nsSocketInputStream(nsSocketTransport* trans)
+    : mTransport(trans) {}
+
+// called on the socket transport thread...
+//
+//   condition : failure code if socket has been closed
+//
+void nsSocketInputStream::OnSocketReady(nsresult condition) {
+  SOCKET_LOG(("nsSocketInputStream::OnSocketReady [this=%p cond=%" PRIx32 "]\n",
+              this, static_cast<uint32_t>(condition)));
+
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+
+  nsCOMPtr<nsIInputStreamCallback> callback;
+  {
+    MutexAutoLock lock(mTransport->mLock);
+
+    // update condition, but be careful not to erase an already
+    // existing error condition.
+    if (NS_SUCCEEDED(mCondition)) mCondition = condition;
+
+    // ignore event if only waiting for closure and not closed.
+    if (NS_FAILED(mCondition) || !(mCallbackFlags & WAIT_CLOSURE_ONLY)) {
+      callback = std::move(mCallback);
+      mCallbackFlags = 0;
+    }
+  }
+
+  if (callback) callback->OnInputStreamReady(this);
+}
+
+NS_IMPL_QUERY_INTERFACE(nsSocketInputStream, nsIInputStream,
+                        nsIAsyncInputStream)
+
+NS_IMETHODIMP_(MozExternalRefCountType)
+nsSocketInputStream::AddRef() {
+  ++mReaderRefCnt;
+  return mTransport->AddRef();
+}
+
+NS_IMETHODIMP_(MozExternalRefCountType)
+nsSocketInputStream::Release() {
+  if (--mReaderRefCnt == 0) Close();
+  return mTransport->Release();
+}
+
+NS_IMETHODIMP
+nsSocketInputStream::Close() { return CloseWithStatus(NS_BASE_STREAM_CLOSED); }
+
+NS_IMETHODIMP
+nsSocketInputStream::Available(uint64_t* avail) {
+  SOCKET_LOG(("nsSocketInputStream::Available [this=%p]\n", this));
+
+  *avail = 0;
+
+  PRFileDesc* fd;
+  {
+    MutexAutoLock lock(mTransport->mLock);
+
+    if (NS_FAILED(mCondition)) return mCondition;
+
+    fd = mTransport->GetFD_Locked();
+    if (!fd) return NS_OK;
+  }
+
+  // cannot hold lock while calling NSPR.  (worried about the fact that PSM
+  // synchronously proxies notifications over to the UI thread, which could
+  // mistakenly try to re-enter this code.)
+  int32_t n = PR_Available(fd);
+
+  // PSM does not implement PR_Available() so do a best approximation of it
+  // with MSG_PEEK
+  if ((n == -1) && (PR_GetError() == PR_NOT_IMPLEMENTED_ERROR)) {
+    char c;
+
+    n = PR_Recv(fd, &c, 1, PR_MSG_PEEK, 0);
+    SOCKET_LOG(
+        ("nsSocketInputStream::Available [this=%p] "
+         "using PEEK backup n=%d]\n",
+         this, n));
+  }
+
+  nsresult rv;
+  {
+    MutexAutoLock lock(mTransport->mLock);
+
+    mTransport->ReleaseFD_Locked(fd);
+
+    if (n >= 0) {
+      *avail = n;
+    } else {
+      PRErrorCode code = PR_GetError();
+      if (code == PR_WOULD_BLOCK_ERROR) return NS_OK;
+      mCondition = ErrorAccordingToNSPR(code);
+    }
+    rv = mCondition;
+  }
+  if (NS_FAILED(rv)) mTransport->OnInputClosed(rv);
+  return rv;
+}
+
+NS_IMETHODIMP
+nsSocketInputStream::StreamStatus() {
+  SOCKET_LOG(("nsSocketInputStream::StreamStatus [this=%p]\n", this));
+
+  MutexAutoLock lock(mTransport->mLock);
+  return mCondition;
+}
+
+NS_IMETHODIMP
+nsSocketInputStream::Read(char* buf, uint32_t count, uint32_t* countRead) {
+  SOCKET_LOG(("nsSocketInputStream::Read [this=%p count=%u]\n", this, count));
+
+  *countRead = 0;
+
+  PRFileDesc* fd = nullptr;
+  {
+    MutexAutoLock lock(mTransport->mLock);
+
+    if (NS_FAILED(mCondition)) {
+      return (mCondition == NS_BASE_STREAM_CLOSED) ? NS_OK : mCondition;
+    }
+
+    fd = mTransport->GetFD_Locked();
+    if (!fd) return NS_BASE_STREAM_WOULD_BLOCK;
+  }
+
+  SOCKET_LOG(("  calling PR_Read [count=%u]\n", count));
+
+  // cannot hold lock while calling NSPR.  (worried about the fact that PSM
+  // synchronously proxies notifications over to the UI thread, which could
+  // mistakenly try to re-enter this code.)
+  int32_t n = PR_Read(fd, buf, count);
+
+  SOCKET_LOG(("  PR_Read returned [n=%d]\n", n));
+
+  nsresult rv = NS_OK;
+  {
+    MutexAutoLock lock(mTransport->mLock);
+
+#ifdef ENABLE_SOCKET_TRACING
+    if (n > 0) mTransport->TraceInBuf(buf, n);
+#endif
+
+    mTransport->ReleaseFD_Locked(fd);
+
+    if (n > 0) {
+      mByteCount += (*countRead = n);
+      profiler_count_bandwidth_read_bytes(n);
+    } else if (n < 0) {
+      PRErrorCode code = PR_GetError();
+      if (code == PR_WOULD_BLOCK_ERROR) return NS_BASE_STREAM_WOULD_BLOCK;
+      mCondition = ErrorAccordingToNSPR(code);
+    }
+    rv = mCondition;
+  }
+  if (NS_FAILED(rv)) mTransport->OnInputClosed(rv);
+
+  // only send this notification if we have indeed read some data.
+  // see bug 196827 for an example of why this is important.
+  if (n > 0) mTransport->SendStatus(NS_NET_STATUS_RECEIVING_FROM);
+  return rv;
+}
+
+NS_IMETHODIMP
+nsSocketInputStream::ReadSegments(nsWriteSegmentFun writer, void* closure,
+                                  uint32_t count, uint32_t* countRead) {
+  // socket stream is unbuffered
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsSocketInputStream::IsNonBlocking(bool* nonblocking) {
+  *nonblocking = true;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketInputStream::CloseWithStatus(nsresult reason) {
+  SOCKET_LOG(("nsSocketInputStream::CloseWithStatus [this=%p reason=%" PRIx32
+              "]\n",
+              this, static_cast<uint32_t>(reason)));
+
+  // may be called from any thread
+
+  nsresult rv;
+  {
+    MutexAutoLock lock(mTransport->mLock);
+
+    if (NS_SUCCEEDED(mCondition)) {
+      rv = mCondition = reason;
+    } else {
+      rv = NS_OK;
+    }
+  }
+  if (NS_FAILED(rv)) mTransport->OnInputClosed(rv);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketInputStream::AsyncWait(nsIInputStreamCallback* callback, uint32_t flags,
+                               uint32_t amount, nsIEventTarget* target) {
+  SOCKET_LOG(("nsSocketInputStream::AsyncWait [this=%p]\n", this));
+
+  bool hasError = false;
+  {
+    MutexAutoLock lock(mTransport->mLock);
+
+    if (callback && target) {
+      //
+      // build event proxy
+      //
+      mCallback = NS_NewInputStreamReadyEvent("nsSocketInputStream::AsyncWait",
+                                              callback, target);
+    } else {
+      mCallback = callback;
+    }
+    mCallbackFlags = flags;
+
+    hasError = NS_FAILED(mCondition);
+  }  // unlock mTransport->mLock
+
+  if (hasError) {
+    // OnSocketEvent will call OnInputStreamReady with an error code after
+    // going through the event loop. We do this because most socket callers
+    // do not expect AsyncWait() to synchronously execute the OnInputStreamReady
+    // callback.
+    mTransport->PostEvent(nsSocketTransport::MSG_INPUT_PENDING);
+  } else {
+    mTransport->OnInputPending();
+  }
+
+  return NS_OK;
+}
+
+//-----------------------------------------------------------------------------
+// socket output stream impl
+//-----------------------------------------------------------------------------
+
+nsSocketOutputStream::nsSocketOutputStream(nsSocketTransport* trans)
+    : mTransport(trans) {}
+
+// called on the socket transport thread...
+//
+//   condition : failure code if socket has been closed
+//
+void nsSocketOutputStream::OnSocketReady(nsresult condition) {
+  SOCKET_LOG(("nsSocketOutputStream::OnSocketReady [this=%p cond=%" PRIx32
+              "]\n",
+              this, static_cast<uint32_t>(condition)));
+
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+
+  nsCOMPtr<nsIOutputStreamCallback> callback;
+  {
+    MutexAutoLock lock(mTransport->mLock);
+
+    // update condition, but be careful not to erase an already
+    // existing error condition.
+    if (NS_SUCCEEDED(mCondition)) mCondition = condition;
+
+    // ignore event if only waiting for closure and not closed.
+    if (NS_FAILED(mCondition) || !(mCallbackFlags & WAIT_CLOSURE_ONLY)) {
+      callback = std::move(mCallback);
+      mCallbackFlags = 0;
+    }
+  }
+
+  if (callback) callback->OnOutputStreamReady(this);
+}
+
+NS_IMPL_QUERY_INTERFACE(nsSocketOutputStream, nsIOutputStream,
+                        nsIAsyncOutputStream)
+
+NS_IMETHODIMP_(MozExternalRefCountType)
+nsSocketOutputStream::AddRef() {
+  ++mWriterRefCnt;
+  return mTransport->AddRef();
+}
+
+NS_IMETHODIMP_(MozExternalRefCountType)
+nsSocketOutputStream::Release() {
+  if (--mWriterRefCnt == 0) Close();
+  return mTransport->Release();
+}
+
+NS_IMETHODIMP
+nsSocketOutputStream::Close() { return CloseWithStatus(NS_BASE_STREAM_CLOSED); }
+
+NS_IMETHODIMP
+nsSocketOutputStream::Flush() { return NS_OK; }
+
+NS_IMETHODIMP
+nsSocketOutputStream::StreamStatus() {
+  MutexAutoLock lock(mTransport->mLock);
+  return mCondition;
+}
+
+NS_IMETHODIMP
+nsSocketOutputStream::Write(const char* buf, uint32_t count,
+                            uint32_t* countWritten) {
+  SOCKET_LOG(("nsSocketOutputStream::Write [this=%p count=%u]\n", this, count));
+
+  *countWritten = 0;
+
+  // A write of 0 bytes can be used to force the initial SSL handshake, so do
+  // not reject that.
+
+  PRFileDesc* fd = nullptr;
+  {
+    MutexAutoLock lock(mTransport->mLock);
+
+    if (NS_FAILED(mCondition)) return mCondition;
+
+    fd = mTransport->GetFD_Locked();
+    if (!fd) return NS_BASE_STREAM_WOULD_BLOCK;
+  }
+
+  SOCKET_LOG(("  calling PR_Write [count=%u]\n", count));
+
+  // cannot hold lock while calling NSPR.  (worried about the fact that PSM
+  // synchronously proxies notifications over to the UI thread, which could
+  // mistakenly try to re-enter this code.)
+  int32_t n = PR_Write(fd, buf, count);
+
+  SOCKET_LOG(("  PR_Write returned [n=%d]\n", n));
+
+  nsresult rv = NS_OK;
+  {
+    MutexAutoLock lock(mTransport->mLock);
+
+#ifdef ENABLE_SOCKET_TRACING
+    if (n > 0) mTransport->TraceOutBuf(buf, n);
+#endif
+
+    mTransport->ReleaseFD_Locked(fd);
+
+    if (n > 0) {
+      mByteCount += (*countWritten = n);
+      profiler_count_bandwidth_written_bytes(n);
+    } else if (n < 0) {
+      PRErrorCode code = PR_GetError();
+      if (code == PR_WOULD_BLOCK_ERROR) return NS_BASE_STREAM_WOULD_BLOCK;
+      mCondition = ErrorAccordingToNSPR(code);
+    }
+    rv = mCondition;
+  }
+  if (NS_FAILED(rv)) mTransport->OnOutputClosed(rv);
+
+  // only send this notification if we have indeed written some data.
+  // see bug 196827 for an example of why this is important.
+  if ((n > 0)) {
+    mTransport->SendStatus(NS_NET_STATUS_SENDING_TO);
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsSocketOutputStream::WriteSegments(nsReadSegmentFun reader, void* closure,
+                                    uint32_t count, uint32_t* countRead) {
+  // socket stream is unbuffered
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+nsresult nsSocketOutputStream::WriteFromSegments(
+    nsIInputStream* input, void* closure, const char* fromSegment,
+    uint32_t offset, uint32_t count, uint32_t* countRead) {
+  nsSocketOutputStream* self = (nsSocketOutputStream*)closure;
+  return self->Write(fromSegment, count, countRead);
+}
+
+NS_IMETHODIMP
+nsSocketOutputStream::WriteFrom(nsIInputStream* stream, uint32_t count,
+                                uint32_t* countRead) {
+  return stream->ReadSegments(WriteFromSegments, this, count, countRead);
+}
+
+NS_IMETHODIMP
+nsSocketOutputStream::IsNonBlocking(bool* nonblocking) {
+  *nonblocking = true;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketOutputStream::CloseWithStatus(nsresult reason) {
+  SOCKET_LOG(("nsSocketOutputStream::CloseWithStatus [this=%p reason=%" PRIx32
+              "]\n",
+              this, static_cast<uint32_t>(reason)));
+
+  // may be called from any thread
+
+  nsresult rv;
+  {
+    MutexAutoLock lock(mTransport->mLock);
+
+    if (NS_SUCCEEDED(mCondition)) {
+      rv = mCondition = reason;
+    } else {
+      rv = NS_OK;
+    }
+  }
+  if (NS_FAILED(rv)) mTransport->OnOutputClosed(rv);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketOutputStream::AsyncWait(nsIOutputStreamCallback* callback,
+                                uint32_t flags, uint32_t amount,
+                                nsIEventTarget* target) {
+  SOCKET_LOG(("nsSocketOutputStream::AsyncWait [this=%p]\n", this));
+
+  {
+    MutexAutoLock lock(mTransport->mLock);
+
+    if (callback && target) {
+      //
+      // build event proxy
+      //
+      mCallback = NS_NewOutputStreamReadyEvent(callback, target);
+    } else {
+      mCallback = callback;
+    }
+
+    mCallbackFlags = flags;
+  }
+  mTransport->OnOutputPending();
+  return NS_OK;
+}
+
+//-----------------------------------------------------------------------------
+// socket transport impl
+//-----------------------------------------------------------------------------
+
+nsSocketTransport::nsSocketTransport()
+    : mFD(this),
+      mSocketTransportService(gSocketTransportService),
+      mInput(new nsSocketInputStream(this)),
+      mOutput(new nsSocketOutputStream(this)) {
+  SOCKET_LOG(("creating nsSocketTransport @%p\n", this));
+
+  mTimeouts[TIMEOUT_CONNECT] = UINT16_MAX;     // no timeout
+  mTimeouts[TIMEOUT_READ_WRITE] = UINT16_MAX;  // no timeout
+}
+
+nsSocketTransport::~nsSocketTransport() {
+  MOZ_RELEASE_ASSERT(!mAttached);
+  SOCKET_LOG(("destroying nsSocketTransport @%p\n", this));
+}
+
+nsresult nsSocketTransport::Init(const nsTArray<nsCString>& types,
+                                 const nsACString& host, uint16_t port,
+                                 const nsACString& hostRoute,
+                                 uint16_t portRoute,
+                                 nsIProxyInfo* givenProxyInfo,
+                                 nsIDNSRecord* dnsRecord) {
+  nsCOMPtr<nsProxyInfo> proxyInfo;
+  if (givenProxyInfo) {
+    proxyInfo = do_QueryInterface(givenProxyInfo);
+    NS_ENSURE_ARG(proxyInfo);
+  }
+
+  if (dnsRecord) {
+    mExternalDNSResolution = true;
+    mDNSRecord = do_QueryInterface(dnsRecord);
+    mDNSRecord->IsTRR(&mResolvedByTRR);
+    mDNSRecord->GetEffectiveTRRMode(&mEffectiveTRRMode);
+    mDNSRecord->GetTrrSkipReason(&mTRRSkipReason);
+  }
+
+  // init socket type info
+
+  mOriginHost = host;
+  mOriginPort = port;
+  if (!hostRoute.IsEmpty()) {
+    mHost = hostRoute;
+    mPort = portRoute;
+  } else {
+    mHost = host;
+    mPort = port;
+  }
+
+  // A subtle check we don't enter this method more than once for the socket
+  // transport lifetime.  Disable on TSan builds to prevent race checking, we
+  // don't want an atomic here for perf reasons!
+#ifndef MOZ_TSAN
+  MOZ_ASSERT(!mPortRemappingApplied);
+#endif  // !MOZ_TSAN
+
+  if (proxyInfo) {
+    mHttpsProxy = proxyInfo->IsHTTPS();
+  }
+
+  const char* proxyType = nullptr;
+  mProxyInfo = proxyInfo;
+  if (proxyInfo) {
+    mProxyPort = proxyInfo->Port();
+    mProxyHost = proxyInfo->Host();
+    // grab proxy type (looking for "socks" for example)
+    proxyType = proxyInfo->Type();
+    if (proxyType && (proxyInfo->IsHTTP() || proxyInfo->IsHTTPS() ||
+                      proxyInfo->IsDirect() || !strcmp(proxyType, "unknown"))) {
+      proxyType = nullptr;
+    }
+  }
+
+  SOCKET_LOG1(
+      ("nsSocketTransport::Init [this=%p host=%s:%hu origin=%s:%d "
+       "proxy=%s:%hu]\n",
+       this, mHost.get(), mPort, mOriginHost.get(), mOriginPort,
+       mProxyHost.get(), mProxyPort));
+
+  // include proxy type as a socket type if proxy type is not "http"
+  uint32_t typeCount = types.Length() + (proxyType != nullptr);
+  if (!typeCount) return NS_OK;
+
+  // if we have socket types, then the socket provider service had
+  // better exist!
+  nsresult rv;
+  nsCOMPtr<nsISocketProviderService> spserv =
+      nsSocketProviderService::GetOrCreate();
+
+  if (!mTypes.SetCapacity(typeCount, fallible)) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  // now verify that each socket type has a registered socket provider.
+  for (uint32_t i = 0, type = 0; i < typeCount; ++i) {
+    // store socket types
+    if (i == 0 && proxyType) {
+      mTypes.AppendElement(proxyType);
+    } else {
+      mTypes.AppendElement(types[type++]);
+    }
+
+    nsCOMPtr<nsISocketProvider> provider;
+    rv = spserv->GetSocketProvider(mTypes[i].get(), getter_AddRefs(provider));
+    if (NS_FAILED(rv)) {
+      NS_WARNING("no registered socket provider");
+      return rv;
+    }
+
+    // note if socket type corresponds to a transparent proxy
+    // XXX don't hardcode SOCKS here (use proxy info's flags instead).
+    if (mTypes[i].EqualsLiteral("socks") || mTypes[i].EqualsLiteral("socks4")) {
+      mProxyTransparent = true;
+
+      if (proxyInfo->Flags() & nsIProxyInfo::TRANSPARENT_PROXY_RESOLVES_HOST) {
+        // we want the SOCKS layer to send the hostname
+        // and port to the proxy and let it do the DNS.
+        mProxyTransparentResolvesHost = true;
+      }
+    }
+  }
+
+  return NS_OK;
+}
+
+#if defined(XP_UNIX)
+nsresult nsSocketTransport::InitWithFilename(const char* filename) {
+  return InitWithName(filename, strlen(filename));
+}
+
+nsresult nsSocketTransport::InitWithName(const char* name, size_t length) {
+  if (length > sizeof(mNetAddr.local.path) - 1) {
+    return NS_ERROR_FILE_NAME_TOO_LONG;
+  }
+
+  if (!name[0] && length > 1) {
+    // name is abstract address name that is supported on Linux only
+#  if defined(XP_LINUX)
+    mHost.Assign(name + 1, length - 1);
+#  else
+    return NS_ERROR_SOCKET_ADDRESS_NOT_SUPPORTED;
+#  endif
+  } else {
+    // The name isn't abstract socket address.  So this is Unix domain
+    // socket that has file path.
+    mHost.Assign(name, length);
+  }
+  mPort = 0;
+
+  mNetAddr.local.family = AF_LOCAL;
+  memcpy(mNetAddr.local.path, name, length);
+  mNetAddr.local.path[length] = '\0';
+  mNetAddrIsSet = true;
+
+  return NS_OK;
+}
+#endif
+
+nsresult nsSocketTransport::InitWithConnectedSocket(PRFileDesc* fd,
+                                                    const NetAddr* addr) {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+
+  char buf[kNetAddrMaxCStrBufSize];
+  addr->ToStringBuffer(buf, sizeof(buf));
+  mHost.Assign(buf);
+
+  uint16_t port;
+  if (addr->raw.family == AF_INET) {
+    port = addr->inet.port;
+  } else if (addr->raw.family == AF_INET6) {
+    port = addr->inet6.port;
+  } else {
+    port = 0;
+  }
+  mPort = ntohs(port);
+
+  memcpy(&mNetAddr, addr, sizeof(NetAddr));
+
+  mPollFlags = (PR_POLL_READ | PR_POLL_WRITE | PR_POLL_EXCEPT);
+  mState = STATE_TRANSFERRING;
+  SetSocketName(fd);
+  mNetAddrIsSet = true;
+
+  {
+    MutexAutoLock lock(mLock);
+    NS_ASSERTION(!mFD.IsInitialized(), "already initialized");
+    mFD = fd;
+    mFDref = 1;
+    mFDconnected = true;
+    mPollTimeout = mTimeouts[TIMEOUT_READ_WRITE];
+  }
+
+  // make sure new socket is non-blocking
+  PRSocketOptionData opt;
+  opt.option = PR_SockOpt_Nonblocking;
+  opt.value.non_blocking = true;
+  PR_SetSocketOption(fd, &opt);
+
+  SOCKET_LOG(
+      ("nsSocketTransport::InitWithConnectedSocket [this=%p addr=%s:%hu]\n",
+       this, mHost.get(), mPort));
+
+  // jump to InitiateSocket to get ourselves attached to the STS poll list.
+  return PostEvent(MSG_RETRY_INIT_SOCKET);
+}
+
+nsresult nsSocketTransport::InitWithConnectedSocket(
+    PRFileDesc* aFD, const NetAddr* aAddr, nsIInterfaceRequestor* aCallbacks) {
+  {
+    MutexAutoLock lock(mLock);
+    mCallbacks = aCallbacks;
+  }
+  return InitWithConnectedSocket(aFD, aAddr);
+}
+
+nsresult nsSocketTransport::PostEvent(uint32_t type, nsresult status,
+                                      nsISupports* param,
+                                      std::function<void()>&& task) {
+  SOCKET_LOG(("nsSocketTransport::PostEvent [this=%p type=%u status=%" PRIx32
+              " param=%p]\n",
+              this, type, static_cast<uint32_t>(status), param));
+
+  nsCOMPtr<nsIRunnable> event =
+      new nsSocketEvent(this, type, status, param, std::move(task));
+  if (!event) return NS_ERROR_OUT_OF_MEMORY;
+
+  return mSocketTransportService->Dispatch(event, NS_DISPATCH_NORMAL);
+}
+
+void nsSocketTransport::SendStatus(nsresult status) {
+  SOCKET_LOG1(("nsSocketTransport::SendStatus [this=%p status=%" PRIx32 "]\n",
+               this, static_cast<uint32_t>(status)));
+
+  nsCOMPtr<nsITransportEventSink> sink;
+  uint64_t progress;
+  {
+    MutexAutoLock lock(mLock);
+    sink = mEventSink;
+    switch (status) {
+      case NS_NET_STATUS_SENDING_TO:
+        progress = mOutput->ByteCount(lock);
+        break;
+      case NS_NET_STATUS_RECEIVING_FROM:
+        progress = mInput->ByteCount(lock);
+        break;
+      default:
+        progress = 0;
+        break;
+    }
+  }
+  if (sink) {
+    sink->OnTransportStatus(this, status, progress, -1);
+  }
+}
+
+nsresult nsSocketTransport::ResolveHost() {
+  SOCKET_LOG((
+      "nsSocketTransport::ResolveHost [this=%p %s:%d%s] "
+      "mProxyTransparentResolvesHost=%d\n",
+      this, SocketHost().get(), SocketPort(),
+      mConnectionFlags & nsSocketTransport::BYPASS_CACHE ? " bypass cache" : "",
+      mProxyTransparentResolvesHost));
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+
+  nsresult rv;
+
+  if (!mProxyHost.IsEmpty()) {
+    if (!mProxyTransparent || mProxyTransparentResolvesHost) {
+#if defined(XP_UNIX)
+      MOZ_ASSERT(!mNetAddrIsSet || mNetAddr.raw.family != AF_LOCAL,
+                 "Unix domain sockets can't be used with proxies");
+#endif
+      // When not resolving mHost locally, we still want to ensure that
+      // it only contains valid characters.  See bug 304904 for details.
+      // Sometimes the end host is not yet known and mHost is *
+      if (!net_IsValidHostName(mHost) && !mHost.EqualsLiteral("*")) {
+        SOCKET_LOG(("  invalid hostname %s\n", mHost.get()));
+        return NS_ERROR_UNKNOWN_HOST;
+      }
+    }
+    if (mProxyTransparentResolvesHost) {
+      // Name resolution is done on the server side.  Just pretend
+      // client resolution is complete, this will get picked up later.
+      // since we don't need to do DNS now, we bypass the resolving
+      // step by initializing mNetAddr to an empty address, but we
+      // must keep the port. The SOCKS IO layer will use the hostname
+      // we send it when it's created, rather than the empty address
+      // we send with the connect call.
+      mState = STATE_RESOLVING;
+      mNetAddr.raw.family = AF_INET;
+      mNetAddr.inet.port = htons(SocketPort());
+      mNetAddr.inet.ip = htonl(INADDR_ANY);
+      return PostEvent(MSG_DNS_LOOKUP_COMPLETE, NS_OK, nullptr);
+    }
+  }
+
+  if (mExternalDNSResolution) {
+    MOZ_ASSERT(mDNSRecord);
+    mState = STATE_RESOLVING;
+    return PostEvent(MSG_DNS_LOOKUP_COMPLETE, NS_OK, nullptr);
+  }
+
+  nsCOMPtr<nsIDNSService> dns = nullptr;
+  auto initTask = [&dns]() { dns = do_GetService(kDNSServiceCID); };
+  if (!NS_IsMainThread()) {
+    // Forward to the main thread synchronously.
+    RefPtr<nsIThread> mainThread = do_GetMainThread();
+    if (!mainThread) {
+      return NS_ERROR_FAILURE;
+    }
+
+    SyncRunnable::DispatchToThread(
+        mainThread,
+        NS_NewRunnableFunction("nsSocketTransport::ResolveHost->GetDNSService",
+                               initTask));
+  } else {
+    initTask();
+  }
+  if (!dns) {
+    return NS_ERROR_FAILURE;
+  }
+
+  mResolving = true;
+
+  nsIDNSService::DNSFlags dnsFlags = nsIDNSService::RESOLVE_DEFAULT_FLAGS;
+  if (mConnectionFlags & nsSocketTransport::BYPASS_CACHE) {
+    dnsFlags = nsIDNSService::RESOLVE_BYPASS_CACHE;
+  }
+  if (mConnectionFlags & nsSocketTransport::REFRESH_CACHE) {
+    dnsFlags = nsIDNSService::RESOLVE_REFRESH_CACHE;
+  }
+  if (mConnectionFlags & nsSocketTransport::DISABLE_IPV6) {
+    dnsFlags |= nsIDNSService::RESOLVE_DISABLE_IPV6;
+  }
+  if (mConnectionFlags & nsSocketTransport::DISABLE_IPV4) {
+    dnsFlags |= nsIDNSService::RESOLVE_DISABLE_IPV4;
+  }
+  if (mConnectionFlags & nsSocketTransport::DISABLE_TRR) {
+    dnsFlags |= nsIDNSService::RESOLVE_DISABLE_TRR;
+  }
+
+  if (mConnectionFlags & nsSocketTransport::USE_IP_HINT_ADDRESS) {
+    dnsFlags |= nsIDNSService::RESOLVE_IP_HINT;
+  }
+
+  dnsFlags |= nsIDNSService::GetFlagsFromTRRMode(
+      nsISocketTransport::GetTRRModeFromFlags(mConnectionFlags));
+
+  // When we get here, we are not resolving using any configured proxy likely
+  // because of individual proxy setting on the request or because the host is
+  // excluded from proxying.  Hence, force resolution despite global proxy-DNS
+  // configuration.
+  dnsFlags |= nsIDNSService::RESOLVE_IGNORE_SOCKS_DNS;
+
+  NS_ASSERTION(!(dnsFlags & nsIDNSService::RESOLVE_DISABLE_IPV6) ||
+                   !(dnsFlags & nsIDNSService::RESOLVE_DISABLE_IPV4),
+               "Setting both RESOLVE_DISABLE_IPV6 and RESOLVE_DISABLE_IPV4");
+
+  SendStatus(NS_NET_STATUS_RESOLVING_HOST);
+
+  if (!SocketHost().Equals(mOriginHost)) {
+    SOCKET_LOG(("nsSocketTransport %p origin %s doing dns for %s\n", this,
+                mOriginHost.get(), SocketHost().get()));
+  }
+  rv =
+      dns->AsyncResolveNative(SocketHost(), nsIDNSService::RESOLVE_TYPE_DEFAULT,
+                              dnsFlags, nullptr, this, mSocketTransportService,
+                              mOriginAttributes, getter_AddRefs(mDNSRequest));
+
+  if (NS_SUCCEEDED(rv)) {
+    SOCKET_LOG(("  advancing to STATE_RESOLVING\n"));
+    mState = STATE_RESOLVING;
+  }
+  return rv;
+}
+
+nsresult nsSocketTransport::BuildSocket(PRFileDesc*& fd, bool& proxyTransparent,
+                                        bool& usingSSL) {
+  SOCKET_LOG(("nsSocketTransport::BuildSocket [this=%p]\n", this));
+
+  nsresult rv = NS_OK;
+
+  proxyTransparent = false;
+  usingSSL = false;
+
+  if (mTypes.IsEmpty()) {
+    fd = PR_OpenTCPSocket(mNetAddr.raw.family);
+    if (!fd) {
+      SOCKET_LOG(("  error creating TCP nspr socket [rv=%" PRIx32 "]\n",
+                  static_cast<uint32_t>(rv)));
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+    return NS_OK;
+  }
+
+#if defined(XP_UNIX)
+  MOZ_ASSERT(!mNetAddrIsSet || mNetAddr.raw.family != AF_LOCAL,
+             "Unix domain sockets can't be used with socket types");
+#endif
+
+  fd = nullptr;
+
+  uint32_t controlFlags = 0;
+  if (mProxyTransparentResolvesHost) {
+    controlFlags |= nsISocketProvider::PROXY_RESOLVES_HOST;
+  }
+
+  if (mConnectionFlags & nsISocketTransport::ANONYMOUS_CONNECT) {
+    controlFlags |= nsISocketProvider::ANONYMOUS_CONNECT;
+  }
+
+  if (mConnectionFlags & nsISocketTransport::NO_PERMANENT_STORAGE) {
+    controlFlags |= nsISocketProvider::NO_PERMANENT_STORAGE;
+  }
+
+  if (mConnectionFlags & nsISocketTransport::BE_CONSERVATIVE) {
+    controlFlags |= nsISocketProvider::BE_CONSERVATIVE;
+  }
+
+  if (mConnectionFlags & nsISocketTransport::DONT_TRY_ECH) {
+    controlFlags |= nsISocketProvider::DONT_TRY_ECH;
+  }
+
+  if (mConnectionFlags & nsISocketTransport::IS_RETRY) {
+    controlFlags |= nsISocketProvider::IS_RETRY;
+  }
+
+  if (mConnectionFlags &
+      nsISocketTransport::ANONYMOUS_CONNECT_ALLOW_CLIENT_CERT) {
+    controlFlags |= nsISocketProvider::ANONYMOUS_CONNECT_ALLOW_CLIENT_CERT;
+  }
+
+  if (mConnectionFlags & nsISocketTransport::IS_SPECULATIVE_CONNECTION) {
+    controlFlags |= nsISocketProvider::IS_SPECULATIVE_CONNECTION;
+  }
+
+  if (mResolvedByTRR) {
+    controlFlags |= nsISocketProvider::USED_PRIVATE_DNS;
+  }
+
+  // by setting host to mOriginHost, instead of mHost we send the
+  // SocketProvider (e.g. PSM) the origin hostname but can still do DNS
+  // on an explicit alternate service host name
+  const char* host = mOriginHost.get();
+  int32_t port = (int32_t)mOriginPort;
+
+  nsCOMPtr<nsISocketProviderService> spserv =
+      nsSocketProviderService::GetOrCreate();
+  nsCOMPtr<nsIProxyInfo> proxyInfo = mProxyInfo;
+
+  uint32_t i;
+  for (i = 0; i < mTypes.Length(); ++i) {
+    nsCOMPtr<nsISocketProvider> provider;
+
+    SOCKET_LOG(("  pushing io layer [%u:%s]\n", i, mTypes[i].get()));
+
+    rv = spserv->GetSocketProvider(mTypes[i].get(), getter_AddRefs(provider));
+    if (NS_FAILED(rv)) break;
+
+    nsCOMPtr<nsITLSSocketControl> tlsSocketControl;
+    if (i == 0) {
+      // if this is the first type, we'll want the
+      // service to allocate a new socket
+
+      // Most layers _ESPECIALLY_ PSM want the origin name here as they
+      // will use it for secure checks, etc.. and any connection management
+      // differences between the origin name and the routed name can be
+      // taken care of via DNS. However, SOCKS is a special case as there is
+      // no DNS. in the case of SOCKS and PSM the PSM is a separate layer
+      // and receives the origin name.
+      const char* socketProviderHost = host;
+      int32_t socketProviderPort = port;
+      if (mProxyTransparentResolvesHost &&
+          (mTypes[0].EqualsLiteral("socks") ||
+           mTypes[0].EqualsLiteral("socks4"))) {
+        SOCKET_LOG(("SOCKS %d Host/Route override: %s:%d -> %s:%d\n",
+                    mHttpsProxy, socketProviderHost, socketProviderPort,
+                    mHost.get(), mPort));
+        socketProviderHost = mHost.get();
+        socketProviderPort = mPort;
+      }
+
+      // when https proxying we want to just connect to the proxy as if
+      // it were the end host (i.e. expect the proxy's cert)
+
+      rv = provider->NewSocket(
+          mNetAddr.raw.family,
+          mHttpsProxy ? mProxyHost.get() : socketProviderHost,
+          mHttpsProxy ? mProxyPort : socketProviderPort, proxyInfo,
+          mOriginAttributes, controlFlags, mTlsFlags, &fd,
+          getter_AddRefs(tlsSocketControl));
+
+      if (NS_SUCCEEDED(rv) && !fd) {
+        MOZ_ASSERT_UNREACHABLE(
+            "NewSocket succeeded but failed to "
+            "create a PRFileDesc");
+        rv = NS_ERROR_UNEXPECTED;
+      }
+    } else {
+      // the socket has already been allocated,
+      // so we just want the service to add itself
+      // to the stack (such as pushing an io layer)
+      rv = provider->AddToSocket(mNetAddr.raw.family, host, port, proxyInfo,
+                                 mOriginAttributes, controlFlags, mTlsFlags, fd,
+                                 getter_AddRefs(tlsSocketControl));
+    }
+
+    // controlFlags = 0; not used below this point...
+    if (NS_FAILED(rv)) break;
+
+    // if the service was ssl or starttls, we want to hold onto the socket
+    // info
+    bool isSSL = mTypes[i].EqualsLiteral("ssl");
+    if (isSSL || mTypes[i].EqualsLiteral("starttls")) {
+      // remember security info
+      {
+        MutexAutoLock lock(mLock);
+        mTLSSocketControl = tlsSocketControl;
+        SOCKET_LOG(("  [tlsSocketControl=%p callbacks=%p]\n",
+                    mTLSSocketControl.get(), mCallbacks.get()));
+      }
+      // remember if socket type is SSL so we can ProxyStartSSL if need be.
+      usingSSL = isSSL;
+    } else if (mTypes[i].EqualsLiteral("socks") ||
+               mTypes[i].EqualsLiteral("socks4")) {
+      // since socks is transparent, any layers above
+      // it do not have to worry about proxy stuff
+      proxyInfo = nullptr;
+      proxyTransparent = true;
+    }
+  }
+
+  if (NS_FAILED(rv)) {
+    SOCKET_LOG(("  error pushing io layer [%u:%s rv=%" PRIx32 "]\n", i,
+                mTypes[i].get(), static_cast<uint32_t>(rv)));
+    if (fd) {
+      CloseSocket(
+          fd, mSocketTransportService->IsTelemetryEnabledAndNotSleepPhase());
+    }
+  }
+  return rv;
+}
+
+nsresult nsSocketTransport::InitiateSocket() {
+  SOCKET_LOG(("nsSocketTransport::InitiateSocket [this=%p]\n", this));
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+
+  nsresult rv;
+  bool isLocal;
+  IsLocal(&isLocal);
+
+  if (gIOService->IsNetTearingDown()) {
+    return NS_ERROR_ABORT;
+  }
+  if (gIOService->IsOffline()) {
+    if (StaticPrefs::network_disable_localhost_when_offline() || !isLocal) {
+      return NS_ERROR_OFFLINE;
+    }
+  } else if (!isLocal) {
+#ifdef DEBUG
+    // all IP networking has to be done from the parent
+    if (NS_SUCCEEDED(mCondition) && ((mNetAddr.raw.family == AF_INET) ||
+                                     (mNetAddr.raw.family == AF_INET6))) {
+      MOZ_ASSERT(!IsNeckoChild());
+    }
+#endif
+
+    if (NS_SUCCEEDED(mCondition) && xpc::AreNonLocalConnectionsDisabled() &&
+        !(mNetAddr.IsIPAddrAny() || mNetAddr.IsIPAddrLocal() ||
+          mNetAddr.IsIPAddrShared())) {
+      nsAutoCString ipaddr;
+      RefPtr<nsNetAddr> netaddr = new nsNetAddr(&mNetAddr);
+      netaddr->GetAddress(ipaddr);
+      fprintf_stderr(
+          stderr,
+          "FATAL ERROR: Non-local network connections are disabled and a "
+          "connection "
+          "attempt to %s (%s) was made.\nYou should only access hostnames "
+          "available via the test networking proxy (if running mochitests) "
+          "or from a test-specific httpd.js server (if running xpcshell "
+          "tests). "
+          "Browser services should be disabled or redirected to a local "
+          "server.\n",
+          mHost.get(), ipaddr.get());
+      return NS_ERROR_NON_LOCAL_CONNECTION_REFUSED;
+    }
+  }
+
+  // Hosts/Proxy Hosts that are Local IP Literals should not be speculatively
+  // connected - Bug 853423.
+  if (mConnectionFlags & nsISocketTransport::DISABLE_RFC1918 &&
+      mNetAddr.IsIPAddrLocal()) {
+    if (SOCKET_LOG_ENABLED()) {
+      nsAutoCString netAddrCString;
+      netAddrCString.SetLength(kIPv6CStrBufSize);
+      if (!mNetAddr.ToStringBuffer(netAddrCString.BeginWriting(),
+                                   kIPv6CStrBufSize)) {
+        netAddrCString = "<IP-to-string failed>"_ns;
+      }
+      SOCKET_LOG(
+          ("nsSocketTransport::InitiateSocket skipping "
+           "speculative connection for host [%s:%d] proxy "
+           "[%s:%d] with Local IP address [%s]",
+           mHost.get(), mPort, mProxyHost.get(), mProxyPort,
+           netAddrCString.get()));
+    }
+    mCondition = NS_ERROR_CONNECTION_REFUSED;
+    OnSocketDetached(nullptr);
+    return mCondition;
+  }
+
+  //
+  // find out if it is going to be ok to attach another socket to the STS.
+  // if not then we have to wait for the STS to tell us that it is ok.
+  // the notification is asynchronous, which means that when we could be
+  // in a race to call AttachSocket once notified.  for this reason, when
+  // we get notified, we just re-enter this function.  as a result, we are
+  // sure to ask again before calling AttachSocket.  in this way we deal
+  // with the race condition.  though it isn't the most elegant solution,
+  // it is far simpler than trying to build a system that would guarantee
+  // FIFO ordering (which wouldn't even be that valuable IMO).  see bug
+  // 194402 for more info.
+  //
+  if (!mSocketTransportService->CanAttachSocket()) {
+    nsCOMPtr<nsIRunnable> event =
+        new nsSocketEvent(this, MSG_RETRY_INIT_SOCKET);
+    if (!event) return NS_ERROR_OUT_OF_MEMORY;
+    return mSocketTransportService->NotifyWhenCanAttachSocket(event);
+  }
+
+  //
+  // if we already have a connected socket, then just attach and return.
+  //
+  {
+    MutexAutoLock lock(mLock);
+    if (mFD.IsInitialized()) {
+      rv = mSocketTransportService->AttachSocket(mFD, this);
+      if (NS_SUCCEEDED(rv)) mAttached = true;
+      return rv;
+    }
+  }
+
+  //
+  // create new socket fd, push io layers, etc.
+  //
+  PRFileDesc* fd;
+  bool proxyTransparent;
+  bool usingSSL;
+
+  rv = BuildSocket(fd, proxyTransparent, usingSSL);
+  if (NS_FAILED(rv)) {
+    SOCKET_LOG(
+        ("  BuildSocket failed [rv=%" PRIx32 "]\n", static_cast<uint32_t>(rv)));
+    return rv;
+  }
+
+  // create proxy via IOActivityMonitor
+  IOActivityMonitor::MonitorSocket(fd);
+
+#ifdef FUZZING
+  if (StaticPrefs::fuzzing_necko_enabled()) {
+    rv = AttachFuzzyIOLayer(fd);
+    if (NS_FAILED(rv)) {
+      SOCKET_LOG(("Failed to attach fuzzing IOLayer [rv=%" PRIx32 "].\n",
+                  static_cast<uint32_t>(rv)));
+      return rv;
+    }
+    SOCKET_LOG(("Successfully attached fuzzing IOLayer.\n"));
+
+    if (usingSSL) {
+      mTLSSocketControl = new FuzzySocketControl();
+    }
+  }
+#endif
+
+  PRStatus status;
+
+  // Make the socket non-blocking...
+  PRSocketOptionData opt;
+  opt.option = PR_SockOpt_Nonblocking;
+  opt.value.non_blocking = true;
+  status = PR_SetSocketOption(fd, &opt);
+  NS_ASSERTION(status == PR_SUCCESS, "unable to make socket non-blocking");
+
+  if (mReuseAddrPort) {
+    SOCKET_LOG(("  Setting port/addr reuse socket options\n"));
+
+    // Set ReuseAddr for TCP sockets to enable having several
+    // sockets bound to same local IP and port
+    PRSocketOptionData opt_reuseaddr;
+    opt_reuseaddr.option = PR_SockOpt_Reuseaddr;
+    opt_reuseaddr.value.reuse_addr = PR_TRUE;
+    status = PR_SetSocketOption(fd, &opt_reuseaddr);
+    if (status != PR_SUCCESS) {
+      SOCKET_LOG(("  Couldn't set reuse addr socket option: %d\n", status));
+    }
+
+    // And also set ReusePort for platforms supporting this socket option
+    PRSocketOptionData opt_reuseport;
+    opt_reuseport.option = PR_SockOpt_Reuseport;
+    opt_reuseport.value.reuse_port = PR_TRUE;
+    status = PR_SetSocketOption(fd, &opt_reuseport);
+    if (status != PR_SUCCESS &&
+        PR_GetError() != PR_OPERATION_NOT_SUPPORTED_ERROR) {
+      SOCKET_LOG(("  Couldn't set reuse port socket option: %d\n", status));
+    }
+  }
+
+  // disable the nagle algorithm - if we rely on it to coalesce writes into
+  // full packets the final packet of a multi segment POST/PUT or pipeline
+  // sequence is delayed a full rtt
+  opt.option = PR_SockOpt_NoDelay;
+  opt.value.no_delay = true;
+  PR_SetSocketOption(fd, &opt);
+
+  // if the network.tcp.sendbuffer preference is set, use it to size SO_SNDBUF
+  // The Windows default of 8KB is too small and as of vista sp1, autotuning
+  // only applies to receive window
+  int32_t sndBufferSize;
+  mSocketTransportService->GetSendBufferSize(&sndBufferSize);
+  if (sndBufferSize > 0) {
+    opt.option = PR_SockOpt_SendBufferSize;
+    opt.value.send_buffer_size = sndBufferSize;
+    PR_SetSocketOption(fd, &opt);
+  }
+
+  if (mQoSBits) {
+    opt.option = PR_SockOpt_IpTypeOfService;
+    opt.value.tos = mQoSBits;
+    PR_SetSocketOption(fd, &opt);
+  }
+
+#if defined(XP_WIN)
+  // The linger is turned off by default. This is not a hard close, but
+  // closesocket should return immediately and operating system tries to send
+  // remaining data for certain, implementation specific, amount of time.
+  // https://msdn.microsoft.com/en-us/library/ms739165.aspx
+  //
+  // Turn the linger option on an set the interval to 0. This will cause hard
+  // close of the socket.
+  opt.option = PR_SockOpt_Linger;
+  opt.value.linger.polarity = 1;
+  opt.value.linger.linger = 0;
+  PR_SetSocketOption(fd, &opt);
+#endif
+
+  // up to here, mFD will only be accessed by us
+
+  // assign mFD so that we can properly handle OnSocketDetached before we've
+  // established a connection.
+  {
+    MutexAutoLock lock(mLock);
+    // inform socket transport about this newly created socket...
+    rv = mSocketTransportService->AttachSocket(fd, this);
+    if (NS_FAILED(rv)) {
+      CloseSocket(
+          fd, mSocketTransportService->IsTelemetryEnabledAndNotSleepPhase());
+      return rv;
+    }
+    mAttached = true;
+
+    mFD = fd;
+    mFDref = 1;
+    mFDconnected = false;
+    mPollTimeout = mTimeouts[TIMEOUT_CONNECT];
+  }
+
+  SOCKET_LOG(("  advancing to STATE_CONNECTING\n"));
+  mState = STATE_CONNECTING;
+  SendStatus(NS_NET_STATUS_CONNECTING_TO);
+
+  if (SOCKET_LOG_ENABLED()) {
+    char buf[kNetAddrMaxCStrBufSize];
+    mNetAddr.ToStringBuffer(buf, sizeof(buf));
+    SOCKET_LOG(("  trying address: %s\n", buf));
+  }
+
+  //
+  // Initiate the connect() to the host...
+  //
+  PRNetAddr prAddr;
+  memset(&prAddr, 0, sizeof(prAddr));
+  {
+    if (mBindAddr) {
+      MutexAutoLock lock(mLock);
+      NetAddrToPRNetAddr(mBindAddr.get(), &prAddr);
+      status = PR_Bind(fd, &prAddr);
+      if (status != PR_SUCCESS) {
+        return NS_ERROR_FAILURE;
+      }
+      mBindAddr = nullptr;
+    }
+  }
+
+  NetAddrToPRNetAddr(&mNetAddr, &prAddr);
+
+#ifdef XP_WIN
+  // Find the real tcp socket and set non-blocking once again!
+  // Bug 1158189.
+  PRFileDesc* bottom = PR_GetIdentitiesLayer(fd, PR_NSPR_IO_LAYER);
+  if (bottom) {
+    PROsfd osfd = PR_FileDesc2NativeHandle(bottom);
+    u_long nonblocking = 1;
+    if (ioctlsocket(osfd, FIONBIO, &nonblocking) != 0) {
+      NS_WARNING("Socket could not be set non-blocking!");
+      return NS_ERROR_FAILURE;
+    }
+  }
+#endif
+
+  if (mTLSSocketControl) {
+    if (!mEchConfig.IsEmpty() &&
+        !(mConnectionFlags & (DONT_TRY_ECH | BE_CONSERVATIVE))) {
+      SOCKET_LOG(("nsSocketTransport::InitiateSocket set echconfig."));
+      rv = mTLSSocketControl->SetEchConfig(mEchConfig);
+      if (NS_FAILED(rv)) {
+        return rv;
+      }
+      mEchConfigUsed = true;
+    }
+  }
+
+  // We use PRIntervalTime here because we need
+  // nsIOService::LastOfflineStateChange time and
+  // nsIOService::LastConectivityChange time to be atomic.
+  PRIntervalTime connectStarted = 0;
+  if (gSocketTransportService->IsTelemetryEnabledAndNotSleepPhase()) {
+    connectStarted = PR_IntervalNow();
+  }
+
+  if (Telemetry::CanRecordPrereleaseData() ||
+      Telemetry::CanRecordReleaseData()) {
+    if (NS_FAILED(AttachNetworkDataCountLayer(fd))) {
+      SOCKET_LOG(
+          ("nsSocketTransport::InitiateSocket "
+           "AttachNetworkDataCountLayer failed [this=%p]\n",
+           this));
+    }
+  }
+
+  bool connectCalled = true;  // This is only needed for telemetry.
+  status = PR_Connect(fd, &prAddr, NS_SOCKET_CONNECT_TIMEOUT);
+  PRErrorCode code = PR_GetError();
+  if (status == PR_SUCCESS) {
+    PR_SetFDInheritable(fd, false);
+  }
+
+  if (gSocketTransportService->IsTelemetryEnabledAndNotSleepPhase() &&
+      connectStarted && connectCalled) {
+    SendPRBlockingTelemetry(
+        connectStarted, Telemetry::PRCONNECT_BLOCKING_TIME_NORMAL,
+        Telemetry::PRCONNECT_BLOCKING_TIME_SHUTDOWN,
+        Telemetry::PRCONNECT_BLOCKING_TIME_CONNECTIVITY_CHANGE,
+        Telemetry::PRCONNECT_BLOCKING_TIME_LINK_CHANGE,
+        Telemetry::PRCONNECT_BLOCKING_TIME_OFFLINE);
+  }
+
+  if (status == PR_SUCCESS) {
+    //
+    // we are connected!
+    //
+    OnSocketConnected();
+  } else {
+#if defined(TEST_CONNECT_ERRORS)
+    code = RandomizeConnectError(code);
+#endif
+    //
+    // If the PR_Connect(...) would block, then poll for a connection.
+    //
+    if ((PR_WOULD_BLOCK_ERROR == code) || (PR_IN_PROGRESS_ERROR == code)) {
+      mPollFlags = (PR_POLL_EXCEPT | PR_POLL_WRITE);
+      //
+      // If the socket is already connected, then return success...
+      //
+    } else if (PR_IS_CONNECTED_ERROR == code) {
+      //
+      // we are connected!
+      //
+      OnSocketConnected();
+
+      if (mTLSSocketControl && !mProxyHost.IsEmpty() && proxyTransparent &&
+          usingSSL) {
+        // if the connection phase is finished, and the ssl layer has
+        // been pushed, and we were proxying (transparently; ie. nothing
+        // has to happen in the protocol layer above us), it's time for
+        // the ssl to start doing it's thing.
+        SOCKET_LOG(("  calling ProxyStartSSL()\n"));
+        mTLSSocketControl->ProxyStartSSL();
+        // XXX what if we were forced to poll on the socket for a successful
+        // connection... wouldn't we need to call ProxyStartSSL after a call
+        // to PR_ConnectContinue indicates that we are connected?
+        //
+        // XXX this appears to be what the old socket transport did.  why
+        // isn't this broken?
+      }
+    }
+    //
+    // A SOCKS request was rejected; get the actual error code from
+    // the OS error
+    //
+    else if (PR_UNKNOWN_ERROR == code && mProxyTransparent &&
+             !mProxyHost.IsEmpty()) {
+      code = PR_GetOSError();
+      rv = ErrorAccordingToNSPR(code);
+    }
+    //
+    // The connection was refused...
+    //
+    else {
+      if (gSocketTransportService->IsTelemetryEnabledAndNotSleepPhase() &&
+          connectStarted && connectCalled) {
+        SendPRBlockingTelemetry(
+            connectStarted, Telemetry::PRCONNECT_FAIL_BLOCKING_TIME_NORMAL,
+            Telemetry::PRCONNECT_FAIL_BLOCKING_TIME_SHUTDOWN,
+            Telemetry::PRCONNECT_FAIL_BLOCKING_TIME_CONNECTIVITY_CHANGE,
+            Telemetry::PRCONNECT_FAIL_BLOCKING_TIME_LINK_CHANGE,
+            Telemetry::PRCONNECT_FAIL_BLOCKING_TIME_OFFLINE);
+      }
+
+      rv = ErrorAccordingToNSPR(code);
+      if ((rv == NS_ERROR_CONNECTION_REFUSED) && !mProxyHost.IsEmpty()) {
+        rv = NS_ERROR_PROXY_CONNECTION_REFUSED;
+      }
+    }
+  }
+  return rv;
+}
+
+bool nsSocketTransport::RecoverFromError() {
+  NS_ASSERTION(NS_FAILED(mCondition), "there should be something wrong");
+
+  SOCKET_LOG(
+      ("nsSocketTransport::RecoverFromError [this=%p state=%x cond=%" PRIx32
+       "]\n",
+       this, mState, static_cast<uint32_t>(mCondition)));
+
+  if (mDoNotRetryToConnect) {
+    SOCKET_LOG(
+        ("nsSocketTransport::RecoverFromError do not retry because "
+         "mDoNotRetryToConnect is set [this=%p]\n",
+         this));
+    return false;
+  }
+
+#if defined(XP_UNIX)
+  // Unix domain connections don't have multiple addresses to try,
+  // so the recovery techniques here don't apply.
+  if (mNetAddrIsSet && mNetAddr.raw.family == AF_LOCAL) return false;
+#endif
+
+  if ((mConnectionFlags & nsSocketTransport::USE_IP_HINT_ADDRESS) &&
+      mCondition == NS_ERROR_UNKNOWN_HOST &&
+      (mState == MSG_DNS_LOOKUP_COMPLETE || mState == MSG_ENSURE_CONNECT)) {
+    SOCKET_LOG(("  try again without USE_IP_HINT_ADDRESS"));
+    mConnectionFlags &= ~nsSocketTransport::USE_IP_HINT_ADDRESS;
+    mState = STATE_CLOSED;
+    return NS_SUCCEEDED(PostEvent(MSG_ENSURE_CONNECT, NS_OK));
+  }
+
+  // can only recover from errors in these states
+  if (mState != STATE_RESOLVING && mState != STATE_CONNECTING) {
+    SOCKET_LOG(("  not in a recoverable state"));
+    return false;
+  }
+
+  nsresult rv;
+
+#ifdef DEBUG
+  {
+    MutexAutoLock lock(mLock);
+    NS_ASSERTION(!mFDconnected, "socket should not be connected");
+  }
+#endif
+
+  // all connection failures need to be reported to DNS so that the next
+  // time we will use a different address if available.
+  // NS_BASE_STREAM_CLOSED is not an actual connection failure, so don't report
+  // to DNS.
+  if (mState == STATE_CONNECTING && mDNSRecord &&
+      mCondition != NS_BASE_STREAM_CLOSED) {
+    mDNSRecord->ReportUnusable(SocketPort());
+  }
+
+  if (mCondition != NS_ERROR_CONNECTION_REFUSED &&
+      mCondition != NS_ERROR_PROXY_CONNECTION_REFUSED &&
+      mCondition != NS_ERROR_NET_TIMEOUT &&
+      mCondition != NS_ERROR_UNKNOWN_HOST &&
+      mCondition != NS_ERROR_UNKNOWN_PROXY_HOST) {
+    SOCKET_LOG(("  not a recoverable error %" PRIx32,
+                static_cast<uint32_t>(mCondition)));
+    return false;
+  }
+
+  bool tryAgain = false;
+
+  if ((mState == STATE_CONNECTING) && mDNSRecord) {
+    if (mNetAddr.raw.family == AF_INET) {
+      if (mSocketTransportService->IsTelemetryEnabledAndNotSleepPhase()) {
+        Telemetry::Accumulate(Telemetry::IPV4_AND_IPV6_ADDRESS_CONNECTIVITY,
+                              UNSUCCESSFUL_CONNECTING_TO_IPV4_ADDRESS);
+      }
+    } else if (mNetAddr.raw.family == AF_INET6) {
+      if (mSocketTransportService->IsTelemetryEnabledAndNotSleepPhase()) {
+        Telemetry::Accumulate(Telemetry::IPV4_AND_IPV6_ADDRESS_CONNECTIVITY,
+                              UNSUCCESSFUL_CONNECTING_TO_IPV6_ADDRESS);
+      }
+    }
+  }
+
+  if (mConnectionFlags & RETRY_WITH_DIFFERENT_IP_FAMILY &&
+      mCondition == NS_ERROR_UNKNOWN_HOST && mState == STATE_RESOLVING &&
+      !mProxyTransparentResolvesHost) {
+    SOCKET_LOG(("  trying lookup again with opposite ip family\n"));
+    mConnectionFlags ^= (DISABLE_IPV6 | DISABLE_IPV4);
+    mConnectionFlags &= ~RETRY_WITH_DIFFERENT_IP_FAMILY;
+    // This will tell the consuming half-open to reset preference on the
+    // connection entry
+    mResetFamilyPreference = true;
+    tryAgain = true;
+  }
+
+  // try next ip address only if past the resolver stage...
+  if (mState == STATE_CONNECTING && mDNSRecord) {
+    nsresult rv = mDNSRecord->GetNextAddr(SocketPort(), &mNetAddr);
+    mDNSRecord->IsTRR(&mResolvedByTRR);
+    mDNSRecord->GetEffectiveTRRMode(&mEffectiveTRRMode);
+    mDNSRecord->GetTrrSkipReason(&mTRRSkipReason);
+    if (NS_SUCCEEDED(rv)) {
+      SOCKET_LOG(("  trying again with next ip address\n"));
+      tryAgain = true;
+    } else if (mExternalDNSResolution) {
+      mRetryDnsIfPossible = true;
+      bool trrEnabled;
+      mDNSRecord->IsTRR(&trrEnabled);
+      // Bug 1648147 - If the server responded with `0.0.0.0` or `::` then we
+      // should intentionally not fallback to regular DNS.
+      if (trrEnabled && !StaticPrefs::network_trr_fallback_on_zero_response() &&
+          ((mNetAddr.raw.family == AF_INET && mNetAddr.inet.ip == 0) ||
+           (mNetAddr.raw.family == AF_INET6 && mNetAddr.inet6.ip.u64[0] == 0 &&
+            mNetAddr.inet6.ip.u64[1] == 0))) {
+        SOCKET_LOG(("  TRR returned 0.0.0.0 and there are no other IPs"));
+        mRetryDnsIfPossible = false;
+      }
+    } else if (mConnectionFlags & RETRY_WITH_DIFFERENT_IP_FAMILY) {
+      SOCKET_LOG(("  failed to connect, trying with opposite ip family\n"));
+      // Drop state to closed.  This will trigger new round of DNS
+      // resolving bellow.
+      mState = STATE_CLOSED;
+      mConnectionFlags ^= (DISABLE_IPV6 | DISABLE_IPV4);
+      mConnectionFlags &= ~RETRY_WITH_DIFFERENT_IP_FAMILY;
+      // This will tell the consuming half-open to reset preference on the
+      // connection entry
+      mResetFamilyPreference = true;
+      tryAgain = true;
+    } else if (!(mConnectionFlags & DISABLE_TRR)) {
+      bool trrEnabled;
+      mDNSRecord->IsTRR(&trrEnabled);
+
+      // Bug 1648147 - If the server responded with `0.0.0.0` or `::` then we
+      // should intentionally not fallback to regular DNS.
+      if (!StaticPrefs::network_trr_fallback_on_zero_response() &&
+          ((mNetAddr.raw.family == AF_INET && mNetAddr.inet.ip == 0) ||
+           (mNetAddr.raw.family == AF_INET6 && mNetAddr.inet6.ip.u64[0] == 0 &&
+            mNetAddr.inet6.ip.u64[1] == 0))) {
+        SOCKET_LOG(("  TRR returned 0.0.0.0 and there are no other IPs"));
+      } else if (trrEnabled) {
+        nsIRequest::TRRMode trrMode = nsIRequest::TRR_DEFAULT_MODE;
+        mDNSRecord->GetEffectiveTRRMode(&trrMode);
+        // If current trr mode is trr only, we should not retry.
+        if (trrMode != nsIRequest::TRR_ONLY_MODE) {
+          // Drop state to closed.  This will trigger a new round of
+          // DNS resolving. Bypass the cache this time since the
+          // cached data came from TRR and failed already!
+          SOCKET_LOG(("  failed to connect with TRR enabled, try w/o\n"));
+          mState = STATE_CLOSED;
+          mConnectionFlags |= DISABLE_TRR | BYPASS_CACHE | REFRESH_CACHE;
+          tryAgain = true;
+        }
+      }
+    }
+  }
+
+  // prepare to try again.
+  if (tryAgain) {
+    uint32_t msg;
+
+    if (mState == STATE_CONNECTING) {
+      mState = STATE_RESOLVING;
+      msg = MSG_DNS_LOOKUP_COMPLETE;
+    } else {
+      mState = STATE_CLOSED;
+      msg = MSG_ENSURE_CONNECT;
+    }
+
+    rv = PostEvent(msg, NS_OK);
+    if (NS_FAILED(rv)) tryAgain = false;
+  }
+
+  return tryAgain;
+}
+
+// called on the socket thread only
+void nsSocketTransport::OnMsgInputClosed(nsresult reason) {
+  SOCKET_LOG(("nsSocketTransport::OnMsgInputClosed [this=%p reason=%" PRIx32
+              "]\n",
+              this, static_cast<uint32_t>(reason)));
+
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+
+  mInputClosed = true;
+  // check if event should affect entire transport
+  if (NS_FAILED(reason) && (reason != NS_BASE_STREAM_CLOSED)) {
+    mCondition = reason;  // XXX except if NS_FAILED(mCondition), right??
+  } else if (mOutputClosed) {
+    mCondition =
+        NS_BASE_STREAM_CLOSED;  // XXX except if NS_FAILED(mCondition), right??
+  } else {
+    if (mState == STATE_TRANSFERRING) mPollFlags &= ~PR_POLL_READ;
+    mInput->OnSocketReady(reason);
+  }
+}
+
+// called on the socket thread only
+void nsSocketTransport::OnMsgOutputClosed(nsresult reason) {
+  SOCKET_LOG(("nsSocketTransport::OnMsgOutputClosed [this=%p reason=%" PRIx32
+              "]\n",
+              this, static_cast<uint32_t>(reason)));
+
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+
+  mOutputClosed = true;
+  // check if event should affect entire transport
+  if (NS_FAILED(reason) && (reason != NS_BASE_STREAM_CLOSED)) {
+    mCondition = reason;  // XXX except if NS_FAILED(mCondition), right??
+  } else if (mInputClosed) {
+    mCondition =
+        NS_BASE_STREAM_CLOSED;  // XXX except if NS_FAILED(mCondition), right??
+  } else {
+    if (mState == STATE_TRANSFERRING) mPollFlags &= ~PR_POLL_WRITE;
+    mOutput->OnSocketReady(reason);
+  }
+}
+
+void nsSocketTransport::OnSocketConnected() {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+  SOCKET_LOG(("  advancing to STATE_TRANSFERRING\n"));
+
+  mPollFlags = (PR_POLL_READ | PR_POLL_WRITE | PR_POLL_EXCEPT);
+  mState = STATE_TRANSFERRING;
+
+  // Set the m*AddrIsSet flags only when state has reached TRANSFERRING
+  // because we need to make sure its value does not change due to failover
+  mNetAddrIsSet = true;
+
+  // assign mFD (must do this within the transport lock), but take care not
+  // to trample over mFDref if mFD is already set.
+  {
+    MutexAutoLock lock(mLock);
+    NS_ASSERTION(mFD.IsInitialized(), "no socket");
+    NS_ASSERTION(mFDref == 1, "wrong socket ref count");
+    SetSocketName(mFD);
+    mFDconnected = true;
+    mPollTimeout = mTimeouts[TIMEOUT_READ_WRITE];
+  }
+
+  // Ensure keepalive is configured correctly if previously enabled.
+  if (mKeepaliveEnabled) {
+    nsresult rv = SetKeepaliveEnabledInternal(true);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      SOCKET_LOG(("  SetKeepaliveEnabledInternal failed rv[0x%" PRIx32 "]",
+                  static_cast<uint32_t>(rv)));
+    }
+  }
+
+  SendStatus(NS_NET_STATUS_CONNECTED_TO);
+}
+
+void nsSocketTransport::SetSocketName(PRFileDesc* fd) {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+  if (mSelfAddrIsSet) {
+    return;
+  }
+
+  PRNetAddr prAddr;
+  memset(&prAddr, 0, sizeof(prAddr));
+  if (PR_GetSockName(fd, &prAddr) == PR_SUCCESS) {
+    PRNetAddrToNetAddr(&prAddr, &mSelfAddr);
+    mSelfAddrIsSet = true;
+  }
+}
+
+PRFileDesc* nsSocketTransport::GetFD_Locked() {
+  mLock.AssertCurrentThreadOwns();
+
+  // mFD is not available to the streams while disconnected.
+  if (!mFDconnected) return nullptr;
+
+  if (mFD.IsInitialized()) mFDref++;
+
+  return mFD;
+}
+
+class ThunkPRClose : public Runnable {
+ public:
+  explicit ThunkPRClose(PRFileDesc* fd)
+      : Runnable("net::ThunkPRClose"), mFD(fd) {}
+
+  NS_IMETHOD Run() override {
+    nsSocketTransport::CloseSocket(
+        mFD, gSocketTransportService->IsTelemetryEnabledAndNotSleepPhase());
+    return NS_OK;
+  }
+
+ private:
+  PRFileDesc* mFD;
+};
+
+void STS_PRCloseOnSocketTransport(PRFileDesc* fd, bool lingerPolarity,
+                                  int16_t lingerTimeout) {
+  if (gSocketTransportService) {
+    // Can't PR_Close() a socket off STS thread. Thunk it to STS to die
+    gSocketTransportService->Dispatch(new ThunkPRClose(fd), NS_DISPATCH_NORMAL);
+  } else {
+    // something horrible has happened
+    NS_ASSERTION(gSocketTransportService, "No STS service");
+  }
+}
+
+void nsSocketTransport::ReleaseFD_Locked(PRFileDesc* fd) {
+  mLock.AssertCurrentThreadOwns();
+
+  NS_ASSERTION(mFD == fd, "wrong fd");
+
+  if (--mFDref == 0) {
+    if (gIOService->IsNetTearingDown() &&
+        ((PR_IntervalNow() - gIOService->NetTearingDownStarted()) >
+         gSocketTransportService->MaxTimeForPrClosePref())) {
+      // If shutdown last to long, let the socket leak and do not close it.
+      SOCKET_LOG(("Intentional leak"));
+    } else {
+      if (mLingerPolarity || mLingerTimeout) {
+        PRSocketOptionData socket_linger;
+        socket_linger.option = PR_SockOpt_Linger;
+        socket_linger.value.linger.polarity = mLingerPolarity;
+        socket_linger.value.linger.linger = mLingerTimeout;
+        PR_SetSocketOption(mFD, &socket_linger);
+      }
+      if (OnSocketThread()) {
+        SOCKET_LOG(("nsSocketTransport: calling PR_Close [this=%p]\n", this));
+        CloseSocket(
+            mFD, mSocketTransportService->IsTelemetryEnabledAndNotSleepPhase());
+      } else {
+        // Can't PR_Close() a socket off STS thread. Thunk it to STS to die
+        STS_PRCloseOnSocketTransport(mFD, mLingerPolarity, mLingerTimeout);
+      }
+    }
+    mFD = nullptr;
+  }
+}
+
+//-----------------------------------------------------------------------------
+// socket event handler impl
+
+void nsSocketTransport::OnSocketEvent(uint32_t type, nsresult status,
+                                      nsISupports* param,
+                                      std::function<void()>&& task) {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+  SOCKET_LOG(
+      ("nsSocketTransport::OnSocketEvent [this=%p type=%u status=%" PRIx32
+       " param=%p]\n",
+       this, type, static_cast<uint32_t>(status), param));
+
+  if (NS_FAILED(mCondition)) {
+    // block event since we're apparently already dead.
+    SOCKET_LOG(("  blocking event [condition=%" PRIx32 "]\n",
+                static_cast<uint32_t>(mCondition)));
+    //
+    // notify input/output streams in case either has a pending notify.
+    //
+    mInput->OnSocketReady(mCondition);
+    mOutput->OnSocketReady(mCondition);
+    return;
+  }
+
+  switch (type) {
+    case MSG_ENSURE_CONNECT:
+      SOCKET_LOG(("  MSG_ENSURE_CONNECT\n"));
+      if (task) {
+        task();
+      }
+
+      // Apply port remapping here so that we do it on the socket thread and
+      // before we process the resolved DNS name or create the socket the first
+      // time.
+      if (!mPortRemappingApplied) {
+        mPortRemappingApplied = true;
+
+        mSocketTransportService->ApplyPortRemap(&mPort);
+        mSocketTransportService->ApplyPortRemap(&mOriginPort);
+      }
+
+      //
+      // ensure that we have created a socket, attached it, and have a
+      // connection.
+      //
+      if (mState == STATE_CLOSED) {
+        // Unix domain sockets are ready to connect; mNetAddr is all we
+        // need. Internet address families require a DNS lookup (or possibly
+        // several) before we can connect.
+#if defined(XP_UNIX)
+        if (mNetAddrIsSet && mNetAddr.raw.family == AF_LOCAL) {
+          mCondition = InitiateSocket();
+        } else {
+#else
+        {
+#endif
+          mCondition = ResolveHost();
+        }
+
+      } else {
+        SOCKET_LOG(("  ignoring redundant event\n"));
+      }
+      break;
+
+    case MSG_DNS_LOOKUP_COMPLETE:
+      if (mDNSRequest) {  // only send this if we actually resolved anything
+        SendStatus(NS_NET_STATUS_RESOLVED_HOST);
+      }
+
+      SOCKET_LOG(("  MSG_DNS_LOOKUP_COMPLETE\n"));
+      mDNSRequest = nullptr;
+
+      if (mDNSRecord) {
+        mDNSRecord->GetNextAddr(SocketPort(), &mNetAddr);
+        mDNSRecord->IsTRR(&mResolvedByTRR);
+        mDNSRecord->GetEffectiveTRRMode(&mEffectiveTRRMode);
+        mDNSRecord->GetTrrSkipReason(&mTRRSkipReason);
+      }
+      // status contains DNS lookup status
+      if (NS_FAILED(status)) {
+        // When using a HTTP proxy, NS_ERROR_UNKNOWN_HOST means the HTTP
+        // proxy host is not found, so we fixup the error code.
+        // For SOCKS proxies (mProxyTransparent == true), the socket
+        // transport resolves the real host here, so there's no fixup
+        // (see bug 226943).
+        if ((status == NS_ERROR_UNKNOWN_HOST) && !mProxyTransparent &&
+            !mProxyHost.IsEmpty()) {
+          mCondition = NS_ERROR_UNKNOWN_PROXY_HOST;
+        } else {
+          mCondition = status;
+        }
+      } else if (mState == STATE_RESOLVING) {
+        mCondition = InitiateSocket();
+      }
+      break;
+
+    case MSG_RETRY_INIT_SOCKET:
+      mCondition = InitiateSocket();
+      break;
+
+    case MSG_INPUT_CLOSED:
+      SOCKET_LOG(("  MSG_INPUT_CLOSED\n"));
+      OnMsgInputClosed(status);
+      break;
+
+    case MSG_INPUT_PENDING:
+      SOCKET_LOG(("  MSG_INPUT_PENDING\n"));
+      OnMsgInputPending();
+      break;
+
+    case MSG_OUTPUT_CLOSED:
+      SOCKET_LOG(("  MSG_OUTPUT_CLOSED\n"));
+      OnMsgOutputClosed(status);
+      break;
+
+    case MSG_OUTPUT_PENDING:
+      SOCKET_LOG(("  MSG_OUTPUT_PENDING\n"));
+      OnMsgOutputPending();
+      break;
+    case MSG_TIMEOUT_CHANGED:
+      SOCKET_LOG(("  MSG_TIMEOUT_CHANGED\n"));
+      {
+        MutexAutoLock lock(mLock);
+        mPollTimeout =
+            mTimeouts[(mState == STATE_TRANSFERRING) ? TIMEOUT_READ_WRITE
+                                                     : TIMEOUT_CONNECT];
+      }
+      break;
+    default:
+      SOCKET_LOG(("  unhandled event!\n"));
+  }
+
+  if (NS_FAILED(mCondition)) {
+    SOCKET_LOG(("  after event [this=%p cond=%" PRIx32 "]\n", this,
+                static_cast<uint32_t>(mCondition)));
+    if (!mAttached) {  // need to process this error ourselves...
+      OnSocketDetached(nullptr);
+    }
+  } else if (mPollFlags == PR_POLL_EXCEPT) {
+    mPollFlags = 0;  // make idle
+  }
+}
+
+uint64_t nsSocketTransport::ByteCountReceived() { return mInput->ByteCount(); }
+
+uint64_t nsSocketTransport::ByteCountSent() { return mOutput->ByteCount(); }
+
+//-----------------------------------------------------------------------------
+// socket handler impl
+
+void nsSocketTransport::OnSocketReady(PRFileDesc* fd, int16_t outFlags) {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+  SOCKET_LOG1(("nsSocketTransport::OnSocketReady [this=%p outFlags=%hd]\n",
+               this, outFlags));
+
+  if (outFlags == -1) {
+    SOCKET_LOG(("socket timeout expired\n"));
+    mCondition = NS_ERROR_NET_TIMEOUT;
+    return;
+  }
+
+  if (mState == STATE_TRANSFERRING) {
+    // if waiting to write and socket is writable or hit an exception.
+    if ((mPollFlags & PR_POLL_WRITE) && (outFlags & ~PR_POLL_READ)) {
+      // assume that we won't need to poll any longer (the stream will
+      // request that we poll again if it is still pending).
+      mPollFlags &= ~PR_POLL_WRITE;
+      mOutput->OnSocketReady(NS_OK);
+    }
+    // if waiting to read and socket is readable or hit an exception.
+    if ((mPollFlags & PR_POLL_READ) && (outFlags & ~PR_POLL_WRITE)) {
+      // assume that we won't need to poll any longer (the stream will
+      // request that we poll again if it is still pending).
+      mPollFlags &= ~PR_POLL_READ;
+      mInput->OnSocketReady(NS_OK);
+    }
+    // Update poll timeout in case it was changed
+    {
+      MutexAutoLock lock(mLock);
+      mPollTimeout = mTimeouts[TIMEOUT_READ_WRITE];
+    }
+  } else if ((mState == STATE_CONNECTING) && !gIOService->IsNetTearingDown()) {
+    // We do not need to do PR_ConnectContinue when we are already
+    // shutting down.
+
+    // We use PRIntervalTime here because we need
+    // nsIOService::LastOfflineStateChange time and
+    // nsIOService::LastConectivityChange time to be atomic.
+    PRIntervalTime connectStarted = 0;
+    if (gSocketTransportService->IsTelemetryEnabledAndNotSleepPhase()) {
+      connectStarted = PR_IntervalNow();
+    }
+
+    PRStatus status = PR_ConnectContinue(fd, outFlags);
+
+    if (gSocketTransportService->IsTelemetryEnabledAndNotSleepPhase() &&
+        connectStarted) {
+      SendPRBlockingTelemetry(
+          connectStarted, Telemetry::PRCONNECTCONTINUE_BLOCKING_TIME_NORMAL,
+          Telemetry::PRCONNECTCONTINUE_BLOCKING_TIME_SHUTDOWN,
+          Telemetry::PRCONNECTCONTINUE_BLOCKING_TIME_CONNECTIVITY_CHANGE,
+          Telemetry::PRCONNECTCONTINUE_BLOCKING_TIME_LINK_CHANGE,
+          Telemetry::PRCONNECTCONTINUE_BLOCKING_TIME_OFFLINE);
+    }
+
+    if (status == PR_SUCCESS) {
+      //
+      // we are connected!
+      //
+      OnSocketConnected();
+
+      if (mNetAddr.raw.family == AF_INET) {
+        if (mSocketTransportService->IsTelemetryEnabledAndNotSleepPhase()) {
+          Telemetry::Accumulate(Telemetry::IPV4_AND_IPV6_ADDRESS_CONNECTIVITY,
+                                SUCCESSFUL_CONNECTING_TO_IPV4_ADDRESS);
+        }
+      } else if (mNetAddr.raw.family == AF_INET6) {
+        if (mSocketTransportService->IsTelemetryEnabledAndNotSleepPhase()) {
+          Telemetry::Accumulate(Telemetry::IPV4_AND_IPV6_ADDRESS_CONNECTIVITY,
+                                SUCCESSFUL_CONNECTING_TO_IPV6_ADDRESS);
+        }
+      }
+    } else {
+      PRErrorCode code = PR_GetError();
+#if defined(TEST_CONNECT_ERRORS)
+      code = RandomizeConnectError(code);
+#endif
+      //
+      // If the connect is still not ready, then continue polling...
+      //
+      if ((PR_WOULD_BLOCK_ERROR == code) || (PR_IN_PROGRESS_ERROR == code)) {
+        // Set up the select flags for connect...
+        mPollFlags = (PR_POLL_EXCEPT | PR_POLL_WRITE);
+        // Update poll timeout in case it was changed
+        {
+          MutexAutoLock lock(mLock);
+          mPollTimeout = mTimeouts[TIMEOUT_CONNECT];
+        }
+      }
+      //
+      // The SOCKS proxy rejected our request. Find out why.
+      //
+      else if (PR_UNKNOWN_ERROR == code && mProxyTransparent &&
+               !mProxyHost.IsEmpty()) {
+        code = PR_GetOSError();
+        mCondition = ErrorAccordingToNSPR(code);
+      } else {
+        //
+        // else, the connection failed...
+        //
+        mCondition = ErrorAccordingToNSPR(code);
+        if ((mCondition == NS_ERROR_CONNECTION_REFUSED) &&
+            !mProxyHost.IsEmpty()) {
+          mCondition = NS_ERROR_PROXY_CONNECTION_REFUSED;
+        }
+        SOCKET_LOG(("  connection failed! [reason=%" PRIx32 "]\n",
+                    static_cast<uint32_t>(mCondition)));
+      }
+    }
+  } else if ((mState == STATE_CONNECTING) && gIOService->IsNetTearingDown()) {
+    // We do not need to do PR_ConnectContinue when we are already
+    // shutting down.
+    SOCKET_LOG(
+        ("We are in shutdown so skip PR_ConnectContinue and set "
+         "and error.\n"));
+    mCondition = NS_ERROR_ABORT;
+  } else {
+    NS_ERROR("unexpected socket state");
+    mCondition = NS_ERROR_UNEXPECTED;
+  }
+
+  if (mPollFlags == PR_POLL_EXCEPT) mPollFlags = 0;  // make idle
+}
+
+// called on the socket thread only
+void nsSocketTransport::OnSocketDetached(PRFileDesc* fd) {
+  SOCKET_LOG(("nsSocketTransport::OnSocketDetached [this=%p cond=%" PRIx32
+              "]\n",
+              this, static_cast<uint32_t>(mCondition)));
+
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+
+  mAttached = false;
+
+  // if we didn't initiate this detach, then be sure to pass an error
+  // condition up to our consumers.  (e.g., STS is shutting down.)
+  if (NS_SUCCEEDED(mCondition)) {
+    if (gIOService->IsOffline()) {
+      mCondition = NS_ERROR_OFFLINE;
+    } else {
+      mCondition = NS_ERROR_ABORT;
+    }
+  }
+
+  // If we are not shutting down try again.
+  if (!gIOService->IsNetTearingDown() && RecoverFromError()) {
+    mCondition = NS_OK;
+  } else {
+    mState = STATE_CLOSED;
+
+    // make sure there isn't any pending DNS request
+    if (mDNSRequest) {
+      mDNSRequest->Cancel(NS_ERROR_ABORT);
+      mDNSRequest = nullptr;
+    }
+
+    //
+    // notify input/output streams
+    //
+    mInput->OnSocketReady(mCondition);
+    mOutput->OnSocketReady(mCondition);
+    if (gIOService->IsNetTearingDown()) {
+      if (mInputCopyContext) {
+        NS_CancelAsyncCopy(mInputCopyContext, mCondition);
+      }
+      if (mOutputCopyContext) {
+        NS_CancelAsyncCopy(mOutputCopyContext, mCondition);
+      }
+    }
+  }
+
+  if (mCondition == NS_ERROR_NET_RESET && mDNSRecord &&
+      mOutput->ByteCount() == 0) {
+    // If we are here, it's likely that we are retrying a transaction. Blocking
+    // the already used address could increase the successful rate of the retry.
+    mDNSRecord->ReportUnusable(SocketPort());
+  }
+
+  // finally, release our reference to the socket (must do this within
+  // the transport lock) possibly closing the socket. Also release our
+  // listeners to break potential refcount cycles.
+
+  // We should be careful not to release mEventSink and mCallbacks while
+  // we're locked, because releasing it might require acquiring the lock
+  // again, so we just null out mEventSink and mCallbacks while we're
+  // holding the lock, and let the stack based objects' destuctors take
+  // care of destroying it if needed.
+  nsCOMPtr<nsIInterfaceRequestor> ourCallbacks;
+  nsCOMPtr<nsITransportEventSink> ourEventSink;
+  {
+    MutexAutoLock lock(mLock);
+    if (mFD.IsInitialized()) {
+      ReleaseFD_Locked(mFD);
+      // flag mFD as unusable; this prevents other consumers from
+      // acquiring a reference to mFD.
+      mFDconnected = false;
+    }
+
+    // We must release mCallbacks and mEventSink to avoid memory leak
+    // but only when RecoverFromError() above failed. Otherwise we lose
+    // link with UI and security callbacks on next connection attempt
+    // round. That would lead e.g. to a broken certificate exception page.
+    if (NS_FAILED(mCondition)) {
+      mCallbacks.swap(ourCallbacks);
+      mEventSink.swap(ourEventSink);
+    }
+  }
+}
+
+void nsSocketTransport::IsLocal(bool* aIsLocal) {
+  {
+    MutexAutoLock lock(mLock);
+
+#if defined(XP_UNIX)
+    // Unix-domain sockets are always local.
+    if (mNetAddr.raw.family == PR_AF_LOCAL) {
+      *aIsLocal = true;
+      return;
+    }
+#endif
+
+    *aIsLocal = mNetAddr.IsLoopbackAddr();
+  }
+}
+
+//-----------------------------------------------------------------------------
+// xpcom api
+
+NS_IMPL_ISUPPORTS(nsSocketTransport, nsISocketTransport, nsITransport,
+                  nsIDNSListener, nsIClassInfo, nsIInterfaceRequestor)
+NS_IMPL_CI_INTERFACE_GETTER(nsSocketTransport, nsISocketTransport, nsITransport,
+                            nsIDNSListener, nsIInterfaceRequestor)
+
+NS_IMETHODIMP
+nsSocketTransport::OpenInputStream(uint32_t flags, uint32_t segsize,
+                                   uint32_t segcount,
+                                   nsIInputStream** aResult) {
+  SOCKET_LOG(
+      ("nsSocketTransport::OpenInputStream [this=%p flags=%x]\n", this, flags));
+
+  NS_ENSURE_TRUE(!mInput->IsReferenced(), NS_ERROR_UNEXPECTED);
+
+  nsresult rv;
+  nsCOMPtr<nsIAsyncInputStream> pipeIn;
+  nsCOMPtr<nsIInputStream> result;
+  nsCOMPtr<nsISupports> inputCopyContext;
+
+  if (!(flags & OPEN_UNBUFFERED) || (flags & OPEN_BLOCKING)) {
+    // XXX if the caller wants blocking, then the caller also gets buffered!
+    // bool openBuffered = !(flags & OPEN_UNBUFFERED);
+    bool openBlocking = (flags & OPEN_BLOCKING);
+
+    net_ResolveSegmentParams(segsize, segcount);
+
+    // create a pipe
+    nsCOMPtr<nsIAsyncOutputStream> pipeOut;
+    NS_NewPipe2(getter_AddRefs(pipeIn), getter_AddRefs(pipeOut), !openBlocking,
+                true, segsize, segcount);
+
+    // async copy from socket to pipe
+    rv = NS_AsyncCopy(mInput.get(), pipeOut, mSocketTransportService,
+                      NS_ASYNCCOPY_VIA_WRITESEGMENTS, segsize, nullptr, nullptr,
+                      true, true, getter_AddRefs(inputCopyContext));
+    if (NS_FAILED(rv)) return rv;
+
+    result = pipeIn;
+  } else {
+    result = mInput.get();
+  }
+
+  // flag input stream as open
+  mInputClosed = false;
+  // mInputCopyContext can be only touched on socket thread
+  auto task = [self = RefPtr{this}, inputCopyContext(inputCopyContext)]() {
+    MOZ_ASSERT(OnSocketThread());
+    self->mInputCopyContext = inputCopyContext;
+  };
+  rv = PostEvent(MSG_ENSURE_CONNECT, NS_OK, nullptr, std::move(task));
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  result.forget(aResult);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::OpenOutputStream(uint32_t flags, uint32_t segsize,
+                                    uint32_t segcount,
+                                    nsIOutputStream** aResult) {
+  SOCKET_LOG(("nsSocketTransport::OpenOutputStream [this=%p flags=%x]\n", this,
+              flags));
+
+  NS_ENSURE_TRUE(!mOutput->IsReferenced(), NS_ERROR_UNEXPECTED);
+
+  nsresult rv;
+  nsCOMPtr<nsIAsyncOutputStream> pipeOut;
+  nsCOMPtr<nsIOutputStream> result;
+  nsCOMPtr<nsISupports> outputCopyContext;
+  if (!(flags & OPEN_UNBUFFERED) || (flags & OPEN_BLOCKING)) {
+    // XXX if the caller wants blocking, then the caller also gets buffered!
+    // bool openBuffered = !(flags & OPEN_UNBUFFERED);
+    bool openBlocking = (flags & OPEN_BLOCKING);
+
+    net_ResolveSegmentParams(segsize, segcount);
+
+    // create a pipe
+    nsCOMPtr<nsIAsyncInputStream> pipeIn;
+    NS_NewPipe2(getter_AddRefs(pipeIn), getter_AddRefs(pipeOut), true,
+                !openBlocking, segsize, segcount);
+
+    // async copy from socket to pipe
+    rv = NS_AsyncCopy(pipeIn, mOutput.get(), mSocketTransportService,
+                      NS_ASYNCCOPY_VIA_READSEGMENTS, segsize, nullptr, nullptr,
+                      true, true, getter_AddRefs(outputCopyContext));
+    if (NS_FAILED(rv)) return rv;
+
+    result = pipeOut;
+  } else {
+    result = mOutput.get();
+  }
+
+  // flag output stream as open
+  mOutputClosed = false;
+
+  // mOutputCopyContext can be only touched on socket thread
+  auto task = [self = RefPtr{this}, outputCopyContext(outputCopyContext)]() {
+    MOZ_ASSERT(OnSocketThread());
+    self->mOutputCopyContext = outputCopyContext;
+  };
+  rv = PostEvent(MSG_ENSURE_CONNECT, NS_OK, nullptr, std::move(task));
+  if (NS_FAILED(rv)) return rv;
+
+  result.forget(aResult);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::Close(nsresult reason) {
+  SOCKET_LOG(("nsSocketTransport::Close %p reason=%" PRIx32, this,
+              static_cast<uint32_t>(reason)));
+
+  if (NS_SUCCEEDED(reason)) reason = NS_BASE_STREAM_CLOSED;
+
+  mDoNotRetryToConnect = true;
+
+  mInput->CloseWithStatus(reason);
+  mOutput->CloseWithStatus(reason);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetTlsSocketControl(nsITLSSocketControl** tlsSocketControl) {
+  MutexAutoLock lock(mLock);
+  *tlsSocketControl = do_AddRef(mTLSSocketControl).take();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetSecurityCallbacks(nsIInterfaceRequestor** callbacks) {
+  MutexAutoLock lock(mLock);
+  *callbacks = do_AddRef(mCallbacks).take();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::SetSecurityCallbacks(nsIInterfaceRequestor* callbacks) {
+  nsCOMPtr<nsIInterfaceRequestor> threadsafeCallbacks;
+  NS_NewNotificationCallbacksAggregation(callbacks, nullptr,
+                                         GetCurrentSerialEventTarget(),
+                                         getter_AddRefs(threadsafeCallbacks));
+  MutexAutoLock lock(mLock);
+  mCallbacks = threadsafeCallbacks;
+  SOCKET_LOG(("Reset callbacks for tlsSocketInfo=%p callbacks=%p\n",
+              mTLSSocketControl.get(), mCallbacks.get()));
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::SetEventSink(nsITransportEventSink* sink,
+                                nsIEventTarget* target) {
+  nsCOMPtr<nsITransportEventSink> temp;
+  if (target) {
+    nsresult rv =
+        net_NewTransportEventSinkProxy(getter_AddRefs(temp), sink, target);
+    if (NS_FAILED(rv)) return rv;
+    sink = temp.get();
+  }
+
+  MutexAutoLock lock(mLock);
+  mEventSink = sink;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::IsAlive(bool* result) {
+  *result = false;
+
+  nsresult conditionWhileLocked = NS_OK;
+  PRFileDescAutoLock fd(this, &conditionWhileLocked);
+  if (NS_FAILED(conditionWhileLocked) || !fd.IsInitialized()) {
+    return NS_OK;
+  }
+
+  // XXX do some idle-time based checks??
+
+  char c;
+  int32_t rval = PR_Recv(fd, &c, 1, PR_MSG_PEEK, 0);
+
+  if ((rval > 0) || (rval < 0 && PR_GetError() == PR_WOULD_BLOCK_ERROR)) {
+    *result = true;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetHost(nsACString& host) {
+  host = SocketHost();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetPort(int32_t* port) {
+  *port = (int32_t)SocketPort();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetScriptableOriginAttributes(
+    JSContext* aCx, JS::MutableHandle<JS::Value> aOriginAttributes) {
+  if (NS_WARN_IF(!ToJSValue(aCx, mOriginAttributes, aOriginAttributes))) {
+    return NS_ERROR_FAILURE;
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::SetScriptableOriginAttributes(
+    JSContext* aCx, JS::Handle<JS::Value> aOriginAttributes) {
+  MutexAutoLock lock(mLock);
+  NS_ENSURE_FALSE(mFD.IsInitialized(), NS_ERROR_FAILURE);
+
+  OriginAttributes attrs;
+  if (!aOriginAttributes.isObject() || !attrs.Init(aCx, aOriginAttributes)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  mOriginAttributes = attrs;
+  return NS_OK;
+}
+
+nsresult nsSocketTransport::GetOriginAttributes(
+    OriginAttributes* aOriginAttributes) {
+  NS_ENSURE_ARG(aOriginAttributes);
+  *aOriginAttributes = mOriginAttributes;
+  return NS_OK;
+}
+
+nsresult nsSocketTransport::SetOriginAttributes(
+    const OriginAttributes& aOriginAttributes) {
+  MutexAutoLock lock(mLock);
+  NS_ENSURE_FALSE(mFD.IsInitialized(), NS_ERROR_FAILURE);
+
+  mOriginAttributes = aOriginAttributes;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetPeerAddr(NetAddr* addr) {
+  // once we are in the connected state, mNetAddr will not change.
+  // so if we can verify that we are in the connected state, then
+  // we can freely access mNetAddr from any thread without being
+  // inside a critical section.
+
+  if (!mNetAddrIsSet) {
+    SOCKET_LOG(
+        ("nsSocketTransport::GetPeerAddr [this=%p state=%d] "
+         "NOT_AVAILABLE because not yet connected.",
+         this, mState));
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  memcpy(addr, &mNetAddr, sizeof(NetAddr));
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetSelfAddr(NetAddr* addr) {
+  // once we are in the connected state, mSelfAddr will not change.
+  // so if we can verify that we are in the connected state, then
+  // we can freely access mSelfAddr from any thread without being
+  // inside a critical section.
+
+  if (!mSelfAddrIsSet) {
+    SOCKET_LOG(
+        ("nsSocketTransport::GetSelfAddr [this=%p state=%d] "
+         "NOT_AVAILABLE because not yet connected.",
+         this, mState));
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  memcpy(addr, &mSelfAddr, sizeof(NetAddr));
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::Bind(NetAddr* aLocalAddr) {
+  NS_ENSURE_ARG(aLocalAddr);
+
+  MutexAutoLock lock(mLock);
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+  if (mAttached) {
+    return NS_ERROR_FAILURE;
+  }
+
+  mBindAddr = MakeUnique<NetAddr>();
+  memcpy(mBindAddr.get(), aLocalAddr, sizeof(NetAddr));
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetScriptablePeerAddr(nsINetAddr** addr) {
+  NetAddr rawAddr;
+
+  nsresult rv;
+  rv = GetPeerAddr(&rawAddr);
+  if (NS_FAILED(rv)) return rv;
+
+  RefPtr<nsNetAddr> netaddr = new nsNetAddr(&rawAddr);
+  netaddr.forget(addr);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetScriptableSelfAddr(nsINetAddr** addr) {
+  NetAddr rawAddr;
+
+  nsresult rv;
+  rv = GetSelfAddr(&rawAddr);
+  if (NS_FAILED(rv)) return rv;
+
+  RefPtr<nsNetAddr> netaddr = new nsNetAddr(&rawAddr);
+  netaddr.forget(addr);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetTimeout(uint32_t type, uint32_t* value) {
+  NS_ENSURE_ARG_MAX(type, nsISocketTransport::TIMEOUT_READ_WRITE);
+  MutexAutoLock lock(mLock);
+  *value = (uint32_t)mTimeouts[type];
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::SetTimeout(uint32_t type, uint32_t value) {
+  NS_ENSURE_ARG_MAX(type, nsISocketTransport::TIMEOUT_READ_WRITE);
+
+  SOCKET_LOG(("nsSocketTransport::SetTimeout %p type=%u, value=%u", this, type,
+              value));
+
+  // truncate overly large timeout values.
+  {
+    MutexAutoLock lock(mLock);
+    mTimeouts[type] = (uint16_t)std::min<uint32_t>(value, UINT16_MAX);
+  }
+  PostEvent(MSG_TIMEOUT_CHANGED);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::SetReuseAddrPort(bool reuseAddrPort) {
+  mReuseAddrPort = reuseAddrPort;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::SetLinger(bool aPolarity, int16_t aTimeout) {
+  MutexAutoLock lock(mLock);
+
+  mLingerPolarity = aPolarity;
+  mLingerTimeout = aTimeout;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::SetQoSBits(uint8_t aQoSBits) {
+  // Don't do any checking here of bits.  Why?  Because as of RFC-4594
+  // several different Class Selector and Assured Forwarding values
+  // have been defined, but that isn't to say more won't be added later.
+  // In that case, any checking would be an impediment to interoperating
+  // with newer QoS definitions.
+
+  mQoSBits = aQoSBits;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetQoSBits(uint8_t* aQoSBits) {
+  *aQoSBits = mQoSBits;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetRecvBufferSize(uint32_t* aSize) {
+  PRFileDescAutoLock fd(this);
+  if (!fd.IsInitialized()) return NS_ERROR_NOT_CONNECTED;
+
+  nsresult rv = NS_OK;
+  PRSocketOptionData opt;
+  opt.option = PR_SockOpt_RecvBufferSize;
+  if (PR_GetSocketOption(fd, &opt) == PR_SUCCESS) {
+    *aSize = opt.value.recv_buffer_size;
+  } else {
+    rv = NS_ERROR_FAILURE;
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetSendBufferSize(uint32_t* aSize) {
+  PRFileDescAutoLock fd(this);
+  if (!fd.IsInitialized()) return NS_ERROR_NOT_CONNECTED;
+
+  nsresult rv = NS_OK;
+  PRSocketOptionData opt;
+  opt.option = PR_SockOpt_SendBufferSize;
+  if (PR_GetSocketOption(fd, &opt) == PR_SUCCESS) {
+    *aSize = opt.value.send_buffer_size;
+  } else {
+    rv = NS_ERROR_FAILURE;
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::SetRecvBufferSize(uint32_t aSize) {
+  PRFileDescAutoLock fd(this);
+  if (!fd.IsInitialized()) return NS_ERROR_NOT_CONNECTED;
+
+  nsresult rv = NS_OK;
+  PRSocketOptionData opt;
+  opt.option = PR_SockOpt_RecvBufferSize;
+  opt.value.recv_buffer_size = aSize;
+  if (PR_SetSocketOption(fd, &opt) != PR_SUCCESS) rv = NS_ERROR_FAILURE;
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::SetSendBufferSize(uint32_t aSize) {
+  PRFileDescAutoLock fd(this);
+  if (!fd.IsInitialized()) return NS_ERROR_NOT_CONNECTED;
+
+  nsresult rv = NS_OK;
+  PRSocketOptionData opt;
+  opt.option = PR_SockOpt_SendBufferSize;
+  opt.value.send_buffer_size = aSize;
+  if (PR_SetSocketOption(fd, &opt) != PR_SUCCESS) rv = NS_ERROR_FAILURE;
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::OnLookupComplete(nsICancelable* request, nsIDNSRecord* rec,
+                                    nsresult status) {
+  SOCKET_LOG(("nsSocketTransport::OnLookupComplete: this=%p status %" PRIx32
+              ".",
+              this, static_cast<uint32_t>(status)));
+
+  if (NS_SUCCEEDED(status)) {
+    mDNSRecord = do_QueryInterface(rec);
+    MOZ_ASSERT(mDNSRecord);
+  }
+
+  if (nsCOMPtr<nsIDNSAddrRecord> addrRecord = do_QueryInterface(rec)) {
+    addrRecord->IsTRR(&mResolvedByTRR);
+    addrRecord->GetEffectiveTRRMode(&mEffectiveTRRMode);
+    addrRecord->GetTrrSkipReason(&mTRRSkipReason);
+  }
+
+  // flag host lookup complete for the benefit of the ResolveHost method.
+  mResolving = false;
+  nsresult rv = PostEvent(MSG_DNS_LOOKUP_COMPLETE, status, nullptr);
+
+  // if posting a message fails, then we should assume that the socket
+  // transport has been shutdown.  this should never happen!  if it does
+  // it means that the socket transport service was shutdown before the
+  // DNS service.
+  if (NS_FAILED(rv)) {
+    NS_WARNING("unable to post DNS lookup complete message");
+  }
+
+  return NS_OK;
+}
+
+// nsIInterfaceRequestor
+NS_IMETHODIMP
+nsSocketTransport::GetInterface(const nsIID& iid, void** result) {
+  if (iid.Equals(NS_GET_IID(nsIDNSRecord)) ||
+      iid.Equals(NS_GET_IID(nsIDNSAddrRecord))) {
+    return mDNSRecord ? mDNSRecord->QueryInterface(iid, result)
+                      : NS_ERROR_NO_INTERFACE;
+  }
+  return this->QueryInterface(iid, result);
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetInterfaces(nsTArray<nsIID>& array) {
+  return NS_CI_INTERFACE_GETTER_NAME(nsSocketTransport)(array);
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetScriptableHelper(nsIXPCScriptable** _retval) {
+  *_retval = nullptr;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetContractID(nsACString& aContractID) {
+  aContractID.SetIsVoid(true);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetClassDescription(nsACString& aClassDescription) {
+  aClassDescription.SetIsVoid(true);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetClassID(nsCID** aClassID) {
+  *aClassID = nullptr;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetFlags(uint32_t* aFlags) {
+  *aFlags = nsIClassInfo::THREADSAFE;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetClassIDNoAlloc(nsCID* aClassIDNoAlloc) {
+  return NS_ERROR_NOT_AVAILABLE;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetConnectionFlags(uint32_t* value) {
+  *value = mConnectionFlags;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::SetConnectionFlags(uint32_t value) {
+  SOCKET_LOG(
+      ("nsSocketTransport::SetConnectionFlags %p flags=%u", this, value));
+
+  mConnectionFlags = value;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::SetIsPrivate(bool aIsPrivate) {
+  mIsPrivate = aIsPrivate;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetTlsFlags(uint32_t* value) {
+  *value = mTlsFlags;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::SetTlsFlags(uint32_t value) {
+  mTlsFlags = value;
+  return NS_OK;
+}
+
+void nsSocketTransport::OnKeepaliveEnabledPrefChange(bool aEnabled) {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+
+  // The global pref toggles keepalive as a system feature; it only affects
+  // an individual socket if keepalive has been specifically enabled for it.
+  // So, ensure keepalive is configured correctly if previously enabled.
+  if (mKeepaliveEnabled) {
+    nsresult rv = SetKeepaliveEnabledInternal(aEnabled);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      SOCKET_LOG(("  SetKeepaliveEnabledInternal [%s] failed rv[0x%" PRIx32 "]",
+                  aEnabled ? "enable" : "disable", static_cast<uint32_t>(rv)));
+    }
+  }
+}
+
+nsresult nsSocketTransport::SetKeepaliveEnabledInternal(bool aEnable) {
+  MOZ_ASSERT(mKeepaliveIdleTimeS > 0 && mKeepaliveIdleTimeS <= kMaxTCPKeepIdle);
+  MOZ_ASSERT(mKeepaliveRetryIntervalS > 0 &&
+             mKeepaliveRetryIntervalS <= kMaxTCPKeepIntvl);
+  MOZ_ASSERT(mKeepaliveProbeCount > 0 &&
+             mKeepaliveProbeCount <= kMaxTCPKeepCount);
+
+  PRFileDescAutoLock fd(this);
+  if (NS_WARN_IF(!fd.IsInitialized())) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  // Only enable if keepalives are globally enabled, but ensure other
+  // options are set correctly on the fd.
+  bool enable = aEnable && mSocketTransportService->IsKeepaliveEnabled();
+  nsresult rv =
+      fd.SetKeepaliveVals(enable, mKeepaliveIdleTimeS, mKeepaliveRetryIntervalS,
+                          mKeepaliveProbeCount);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    SOCKET_LOG(("  SetKeepaliveVals failed rv[0x%" PRIx32 "]",
+                static_cast<uint32_t>(rv)));
+    return rv;
+  }
+  rv = fd.SetKeepaliveEnabled(enable);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    SOCKET_LOG(("  SetKeepaliveEnabled failed rv[0x%" PRIx32 "]",
+                static_cast<uint32_t>(rv)));
+    return rv;
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetKeepaliveEnabled(bool* aResult) {
+  MOZ_ASSERT(aResult);
+
+  *aResult = mKeepaliveEnabled;
+  return NS_OK;
+}
+
+nsresult nsSocketTransport::EnsureKeepaliveValsAreInitialized() {
+  nsresult rv = NS_OK;
+  int32_t val = -1;
+  if (mKeepaliveIdleTimeS == -1) {
+    rv = mSocketTransportService->GetKeepaliveIdleTime(&val);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+    mKeepaliveIdleTimeS = val;
+  }
+  if (mKeepaliveRetryIntervalS == -1) {
+    rv = mSocketTransportService->GetKeepaliveRetryInterval(&val);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+    mKeepaliveRetryIntervalS = val;
+  }
+  if (mKeepaliveProbeCount == -1) {
+    rv = mSocketTransportService->GetKeepaliveProbeCount(&val);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+    mKeepaliveProbeCount = val;
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::SetKeepaliveEnabled(bool aEnable) {
+#if defined(XP_WIN) || defined(XP_UNIX) || defined(XP_MACOSX)
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+
+  if (aEnable == mKeepaliveEnabled) {
+    SOCKET_LOG(("nsSocketTransport::SetKeepaliveEnabled [%p] already %s.", this,
+                aEnable ? "enabled" : "disabled"));
+    return NS_OK;
+  }
+
+  nsresult rv = NS_OK;
+  if (aEnable) {
+    rv = EnsureKeepaliveValsAreInitialized();
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      SOCKET_LOG(
+          ("  SetKeepaliveEnabled [%p] "
+           "error [0x%" PRIx32 "] initializing keepalive vals",
+           this, static_cast<uint32_t>(rv)));
+      return rv;
+    }
+  }
+  SOCKET_LOG(
+      ("nsSocketTransport::SetKeepaliveEnabled [%p] "
+       "%s, idle time[%ds] retry interval[%ds] packet count[%d]: "
+       "globally %s.",
+       this, aEnable ? "enabled" : "disabled", mKeepaliveIdleTimeS,
+       mKeepaliveRetryIntervalS, mKeepaliveProbeCount,
+       mSocketTransportService->IsKeepaliveEnabled() ? "enabled" : "disabled"));
+
+  // Set mKeepaliveEnabled here so that state is maintained; it is possible
+  // that we're in between fds, e.g. the 1st IP address failed, so we're about
+  // to retry on a 2nd from the DNS record.
+  mKeepaliveEnabled = aEnable;
+
+  rv = SetKeepaliveEnabledInternal(aEnable);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    SOCKET_LOG(("  SetKeepaliveEnabledInternal failed rv[0x%" PRIx32 "]",
+                static_cast<uint32_t>(rv)));
+    return rv;
+  }
+
+  return NS_OK;
+#else /* !(defined(XP_WIN) || defined(XP_UNIX) || defined(XP_MACOSX)) */
+  SOCKET_LOG(("nsSocketTransport::SetKeepaliveEnabled unsupported platform"));
+  return NS_ERROR_NOT_IMPLEMENTED;
+#endif
+}
+
+NS_IMETHODIMP
+nsSocketTransport::SetKeepaliveVals(int32_t aIdleTime, int32_t aRetryInterval) {
+#if defined(XP_WIN) || defined(XP_UNIX) || defined(XP_MACOSX)
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+  if (NS_WARN_IF(aIdleTime <= 0 || kMaxTCPKeepIdle < aIdleTime)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+  if (NS_WARN_IF(aRetryInterval <= 0 || kMaxTCPKeepIntvl < aRetryInterval)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  if (aIdleTime == mKeepaliveIdleTimeS &&
+      aRetryInterval == mKeepaliveRetryIntervalS) {
+    SOCKET_LOG(
+        ("nsSocketTransport::SetKeepaliveVals [%p] idle time "
+         "already %ds and retry interval already %ds.",
+         this, mKeepaliveIdleTimeS, mKeepaliveRetryIntervalS));
+    return NS_OK;
+  }
+  mKeepaliveIdleTimeS = aIdleTime;
+  mKeepaliveRetryIntervalS = aRetryInterval;
+
+  nsresult rv = NS_OK;
+  if (mKeepaliveProbeCount == -1) {
+    int32_t val = -1;
+    nsresult rv = mSocketTransportService->GetKeepaliveProbeCount(&val);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+    mKeepaliveProbeCount = val;
+  }
+
+  SOCKET_LOG(
+      ("nsSocketTransport::SetKeepaliveVals [%p] "
+       "keepalive %s, idle time[%ds] retry interval[%ds] "
+       "packet count[%d]",
+       this, mKeepaliveEnabled ? "enabled" : "disabled", mKeepaliveIdleTimeS,
+       mKeepaliveRetryIntervalS, mKeepaliveProbeCount));
+
+  PRFileDescAutoLock fd(this);
+  if (NS_WARN_IF(!fd.IsInitialized())) {
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  rv = fd.SetKeepaliveVals(mKeepaliveEnabled, mKeepaliveIdleTimeS,
+                           mKeepaliveRetryIntervalS, mKeepaliveProbeCount);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+  return NS_OK;
+#else
+  SOCKET_LOG(("nsSocketTransport::SetKeepaliveVals unsupported platform"));
+  return NS_ERROR_NOT_IMPLEMENTED;
+#endif
+}
+
+#ifdef ENABLE_SOCKET_TRACING
+
+#  include <stdio.h>
+#  include <ctype.h>
+#  include "prenv.h"
+
+static void DumpBytesToFile(const char* path, const char* header,
+                            const char* buf, int32_t n) {
+  FILE* fp = fopen(path, "a");
+
+  fprintf(fp, "\n%s [%d bytes]\n", header, n);
+
+  const unsigned char* p;
+  while (n) {
+    p = (const unsigned char*)buf;
+
+    int32_t i, row_max = std::min(16, n);
+
+    for (i = 0; i < row_max; ++i) fprintf(fp, "%02x  ", *p++);
+    for (i = row_max; i < 16; ++i) fprintf(fp, "    ");
+
+    p = (const unsigned char*)buf;
+    for (i = 0; i < row_max; ++i, ++p) {
+      if (isprint(*p))
+        fprintf(fp, "%c", *p);
+      else
+        fprintf(fp, ".");
+    }
+
+    fprintf(fp, "\n");
+    buf += row_max;
+    n -= row_max;
+  }
+
+  fprintf(fp, "\n");
+  fclose(fp);
+}
+
+void nsSocketTransport::TraceInBuf(const char* buf, int32_t n) {
+  char* val = PR_GetEnv("NECKO_SOCKET_TRACE_LOG");
+  if (!val || !*val) return;
+
+  nsAutoCString header;
+  header.AssignLiteral("Reading from: ");
+  header.Append(mHost);
+  header.Append(':');
+  header.AppendInt(mPort);
+
+  DumpBytesToFile(val, header.get(), buf, n);
+}
+
+void nsSocketTransport::TraceOutBuf(const char* buf, int32_t n) {
+  char* val = PR_GetEnv("NECKO_SOCKET_TRACE_LOG");
+  if (!val || !*val) return;
+
+  nsAutoCString header;
+  header.AssignLiteral("Writing to: ");
+  header.Append(mHost);
+  header.Append(':');
+  header.AppendInt(mPort);
+
+  DumpBytesToFile(val, header.get(), buf, n);
+}
+
+#endif
+
+static void LogNSPRError(const char* aPrefix, const void* aObjPtr) {
+#if defined(DEBUG)
+  PRErrorCode errCode = PR_GetError();
+  int errLen = PR_GetErrorTextLength();
+  nsAutoCString errStr;
+  if (errLen > 0) {
+    errStr.SetLength(errLen);
+    PR_GetErrorText(errStr.BeginWriting());
+  }
+  NS_WARNING(
+      nsPrintfCString("%s [%p] NSPR error[0x%x] %s.",
+                      aPrefix ? aPrefix : "nsSocketTransport", aObjPtr, errCode,
+                      errLen > 0 ? errStr.BeginReading() : "<no error text>")
+          .get());
+#endif
+}
+
+nsresult nsSocketTransport::PRFileDescAutoLock::SetKeepaliveEnabled(
+    bool aEnable) {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+  MOZ_ASSERT(!(aEnable && !gSocketTransportService->IsKeepaliveEnabled()),
+             "Cannot enable keepalive if global pref is disabled!");
+  if (aEnable && !gSocketTransportService->IsKeepaliveEnabled()) {
+    return NS_ERROR_ILLEGAL_VALUE;
+  }
+
+  PRSocketOptionData opt;
+
+  opt.option = PR_SockOpt_Keepalive;
+  opt.value.keep_alive = aEnable;
+  PRStatus status = PR_SetSocketOption(mFd, &opt);
+  if (NS_WARN_IF(status != PR_SUCCESS)) {
+    LogNSPRError("nsSocketTransport::PRFileDescAutoLock::SetKeepaliveEnabled",
+                 mSocketTransport);
+    return ErrorAccordingToNSPR(PR_GetError());
+  }
+  return NS_OK;
+}
+
+static void LogOSError(const char* aPrefix, const void* aObjPtr) {
+#if defined(DEBUG)
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+
+#  ifdef XP_WIN
+  DWORD errCode = WSAGetLastError();
+  char* errMessage;
+  FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
+                     FORMAT_MESSAGE_IGNORE_INSERTS,
+                 NULL, errCode, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+                 (LPSTR)&errMessage, 0, NULL);
+  NS_WARNING(nsPrintfCString("%s [%p] OS error[0x%lx] %s",
+                             aPrefix ? aPrefix : "nsSocketTransport", aObjPtr,
+                             errCode,
+                             errMessage ? errMessage : "<no error text>")
+                 .get());
+  LocalFree(errMessage);
+#  else
+  int errCode = errno;
+  char* errMessage = strerror(errno);
+  NS_WARNING(nsPrintfCString("%s [%p] OS error[0x%x] %s",
+                             aPrefix ? aPrefix : "nsSocketTransport", aObjPtr,
+                             errCode,
+                             errMessage ? errMessage : "<no error text>")
+                 .get());
+#  endif
+#endif
+}
+
+/* XXX PR_SetSockOpt does not support setting keepalive values, so native
+ * handles and platform specific apis (setsockopt, WSAIOCtl) are used in this
+ * file. Requires inclusion of NSPR private/pprio.h, and platform headers.
+ */
+
+nsresult nsSocketTransport::PRFileDescAutoLock::SetKeepaliveVals(
+    bool aEnabled, int aIdleTime, int aRetryInterval, int aProbeCount) {
+#if defined(XP_WIN) || defined(XP_UNIX) || defined(XP_MACOSX)
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+  if (NS_WARN_IF(aIdleTime <= 0 || kMaxTCPKeepIdle < aIdleTime)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+  if (NS_WARN_IF(aRetryInterval <= 0 || kMaxTCPKeepIntvl < aRetryInterval)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+  if (NS_WARN_IF(aProbeCount <= 0 || kMaxTCPKeepCount < aProbeCount)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  PROsfd sock = PR_FileDesc2NativeHandle(mFd);
+  if (NS_WARN_IF(sock == -1)) {
+    LogNSPRError("nsSocketTransport::PRFileDescAutoLock::SetKeepaliveVals",
+                 mSocketTransport);
+    return ErrorAccordingToNSPR(PR_GetError());
+  }
+#endif
+
+#if defined(XP_WIN)
+  // Windows allows idle time and retry interval to be set; NOT ping count.
+  struct tcp_keepalive keepalive_vals = {(u_long)aEnabled,
+                                         // Windows uses msec.
+                                         (u_long)(aIdleTime * 1000UL),
+                                         (u_long)(aRetryInterval * 1000UL)};
+  DWORD bytes_returned;
+  int err =
+      WSAIoctl(sock, SIO_KEEPALIVE_VALS, &keepalive_vals,
+               sizeof(keepalive_vals), NULL, 0, &bytes_returned, NULL, NULL);
+  if (NS_WARN_IF(err)) {
+    LogOSError("nsSocketTransport WSAIoctl failed", mSocketTransport);
+    return NS_ERROR_UNEXPECTED;
+  }
+  return NS_OK;
+
+#elif defined(XP_DARWIN)
+  // Darwin uses sec; only supports idle time being set.
+  int err = setsockopt(sock, IPPROTO_TCP, TCP_KEEPALIVE, &aIdleTime,
+                       sizeof(aIdleTime));
+  if (NS_WARN_IF(err)) {
+    LogOSError("nsSocketTransport Failed setting TCP_KEEPALIVE",
+               mSocketTransport);
+    return NS_ERROR_UNEXPECTED;
+  }
+  return NS_OK;
+
+#elif defined(XP_UNIX)
+  // Not all *nix OSes support the following setsockopt() options
+  // ... but we assume they are supported in the Android kernel;
+  // build errors will tell us if they are not.
+#  if defined(ANDROID) || defined(TCP_KEEPIDLE)
+  // Idle time until first keepalive probe; interval between ack'd probes;
+  // seconds.
+  int err = setsockopt(sock, IPPROTO_TCP, TCP_KEEPIDLE, &aIdleTime,
+                       sizeof(aIdleTime));
+  if (NS_WARN_IF(err)) {
+    LogOSError("nsSocketTransport Failed setting TCP_KEEPIDLE",
+               mSocketTransport);
+    return NS_ERROR_UNEXPECTED;
+  }
+
+#  endif
+#  if defined(ANDROID) || defined(TCP_KEEPINTVL)
+  // Interval between unack'd keepalive probes; seconds.
+  err = setsockopt(sock, IPPROTO_TCP, TCP_KEEPINTVL, &aRetryInterval,
+                   sizeof(aRetryInterval));
+  if (NS_WARN_IF(err)) {
+    LogOSError("nsSocketTransport Failed setting TCP_KEEPINTVL",
+               mSocketTransport);
+    return NS_ERROR_UNEXPECTED;
+  }
+
+#  endif
+#  if defined(ANDROID) || defined(TCP_KEEPCNT)
+  // Number of unack'd keepalive probes before connection times out.
+  err = setsockopt(sock, IPPROTO_TCP, TCP_KEEPCNT, &aProbeCount,
+                   sizeof(aProbeCount));
+  if (NS_WARN_IF(err)) {
+    LogOSError("nsSocketTransport Failed setting TCP_KEEPCNT",
+               mSocketTransport);
+    return NS_ERROR_UNEXPECTED;
+  }
+
+#  endif
+  return NS_OK;
+#else
+  MOZ_ASSERT(false,
+             "nsSocketTransport::PRFileDescAutoLock::SetKeepaliveVals "
+             "called on unsupported platform!");
+  return NS_ERROR_UNEXPECTED;
+#endif
+}
+
+void nsSocketTransport::CloseSocket(PRFileDesc* aFd, bool aTelemetryEnabled) {
+#if defined(XP_WIN)
+  AttachShutdownLayer(aFd);
+#endif
+
+  // We use PRIntervalTime here because we need
+  // nsIOService::LastOfflineStateChange time and
+  // nsIOService::LastConectivityChange time to be atomic.
+  PRIntervalTime closeStarted;
+  if (aTelemetryEnabled) {
+    closeStarted = PR_IntervalNow();
+  }
+
+  PR_Close(aFd);
+
+  if (aTelemetryEnabled) {
+    SendPRBlockingTelemetry(
+        closeStarted, Telemetry::PRCLOSE_TCP_BLOCKING_TIME_NORMAL,
+        Telemetry::PRCLOSE_TCP_BLOCKING_TIME_SHUTDOWN,
+        Telemetry::PRCLOSE_TCP_BLOCKING_TIME_CONNECTIVITY_CHANGE,
+        Telemetry::PRCLOSE_TCP_BLOCKING_TIME_LINK_CHANGE,
+        Telemetry::PRCLOSE_TCP_BLOCKING_TIME_OFFLINE);
+  }
+}
+
+void nsSocketTransport::SendPRBlockingTelemetry(
+    PRIntervalTime aStart, Telemetry::HistogramID aIDNormal,
+    Telemetry::HistogramID aIDShutdown,
+    Telemetry::HistogramID aIDConnectivityChange,
+    Telemetry::HistogramID aIDLinkChange, Telemetry::HistogramID aIDOffline) {
+  PRIntervalTime now = PR_IntervalNow();
+  if (gIOService->IsNetTearingDown()) {
+    Telemetry::Accumulate(aIDShutdown, PR_IntervalToMilliseconds(now - aStart));
+
+  } else if (PR_IntervalToSeconds(now - gIOService->LastConnectivityChange()) <
+             60) {
+    Telemetry::Accumulate(aIDConnectivityChange,
+                          PR_IntervalToMilliseconds(now - aStart));
+  } else if (PR_IntervalToSeconds(now - gIOService->LastNetworkLinkChange()) <
+             60) {
+    Telemetry::Accumulate(aIDLinkChange,
+                          PR_IntervalToMilliseconds(now - aStart));
+
+  } else if (PR_IntervalToSeconds(now - gIOService->LastOfflineStateChange()) <
+             60) {
+    Telemetry::Accumulate(aIDOffline, PR_IntervalToMilliseconds(now - aStart));
+  } else {
+    Telemetry::Accumulate(aIDNormal, PR_IntervalToMilliseconds(now - aStart));
+  }
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetResetIPFamilyPreference(bool* aReset) {
+  *aReset = mResetFamilyPreference;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetEchConfigUsed(bool* aEchConfigUsed) {
+  *aEchConfigUsed = mEchConfigUsed;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::SetEchConfig(const nsACString& aEchConfig) {
+  mEchConfig = aEchConfig;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::ResolvedByTRR(bool* aResolvedByTRR) {
+  *aResolvedByTRR = mResolvedByTRR;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsSocketTransport::GetEffectiveTRRMode(
+    nsIRequest::TRRMode* aEffectiveTRRMode) {
+  *aEffectiveTRRMode = mEffectiveTRRMode;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsSocketTransport::GetTrrSkipReason(
+    nsITRRSkipReason::value* aSkipReason) {
+  *aSkipReason = mTRRSkipReason;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetRetryDnsIfPossible(bool* aRetryDns) {
+  *aRetryDns = mRetryDnsIfPossible;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSocketTransport::GetStatus(nsresult* aStatus) {
+  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
+
+  *aStatus = mCondition;
+  return NS_OK;
+}
+
+}  // namespace net
+}  // namespace mozilla