--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/third_party/libuv/src/win/tcp.c	Wed Jan 14 19:39:52 2026 -0800
@@ -0,0 +1,1674 @@
+/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <assert.h>
+#include <stdlib.h>
+
+#include "uv.h"
+#include "internal.h"
+#include "handle-inl.h"
+#include "stream-inl.h"
+#include "req-inl.h"
+
+
+/*
+ * Number of simultaneous pending AcceptEx calls.
+ */
+const unsigned int uv_simultaneous_server_accepts = 32;
+
+/* A zero-size buffer for use by uv_tcp_read */
+static char uv_zero_[] = "";
+
+static int uv__tcp_nodelay(uv_tcp_t* handle, SOCKET socket, int enable) {
+  if (setsockopt(socket,
+                 IPPROTO_TCP,
+                 TCP_NODELAY,
+                 (const char*)&enable,
+                 sizeof enable) == -1) {
+    return WSAGetLastError();
+  }
+  return 0;
+}
+
+
+static int uv__tcp_keepalive(uv_tcp_t* handle, SOCKET socket, int enable, unsigned int delay) {
+  if (setsockopt(socket,
+                 SOL_SOCKET,
+                 SO_KEEPALIVE,
+                 (const char*)&enable,
+                 sizeof enable) == -1) {
+    return WSAGetLastError();
+  }
+
+  if (!enable)
+    return 0;
+
+  if (delay < 1)
+    return UV_EINVAL;
+
+  if (setsockopt(socket,
+                 IPPROTO_TCP,
+                 TCP_KEEPALIVE,
+                 (const char*)&delay,
+                 sizeof delay) == -1) {
+    return WSAGetLastError();
+  }
+
+  return 0;
+}
+
+
+static int uv__tcp_set_socket(uv_loop_t* loop,
+                              uv_tcp_t* handle,
+                              SOCKET socket,
+                              int family,
+                              int imported) {
+  DWORD yes = 1;
+  int non_ifs_lsp;
+  int err;
+
+  if (handle->socket != INVALID_SOCKET)
+    return UV_EBUSY;
+
+  /* Set the socket to nonblocking mode */
+  if (ioctlsocket(socket, FIONBIO, &yes) == SOCKET_ERROR) {
+    return WSAGetLastError();
+  }
+
+  /* Make the socket non-inheritable */
+  if (!SetHandleInformation((HANDLE) socket, HANDLE_FLAG_INHERIT, 0))
+    return GetLastError();
+
+  /* Associate it with the I/O completion port. Use uv_handle_t pointer as
+   * completion key. */
+  if (CreateIoCompletionPort((HANDLE)socket,
+                             loop->iocp,
+                             (ULONG_PTR)socket,
+                             0) == NULL) {
+    if (imported) {
+      handle->flags |= UV_HANDLE_EMULATE_IOCP;
+    } else {
+      return GetLastError();
+    }
+  }
+
+  if (family == AF_INET6) {
+    non_ifs_lsp = uv_tcp_non_ifs_lsp_ipv6;
+  } else {
+    non_ifs_lsp = uv_tcp_non_ifs_lsp_ipv4;
+  }
+
+  if (!(handle->flags & UV_HANDLE_EMULATE_IOCP) && !non_ifs_lsp) {
+    UCHAR sfcnm_flags =
+        FILE_SKIP_SET_EVENT_ON_HANDLE | FILE_SKIP_COMPLETION_PORT_ON_SUCCESS;
+    if (!SetFileCompletionNotificationModes((HANDLE) socket, sfcnm_flags))
+      return GetLastError();
+    handle->flags |= UV_HANDLE_SYNC_BYPASS_IOCP;
+  }
+
+  if (handle->flags & UV_HANDLE_TCP_NODELAY) {
+    err = uv__tcp_nodelay(handle, socket, 1);
+    if (err)
+      return err;
+  }
+
+  /* TODO: Use stored delay. */
+  if (handle->flags & UV_HANDLE_TCP_KEEPALIVE) {
+    err = uv__tcp_keepalive(handle, socket, 1, 60);
+    if (err)
+      return err;
+  }
+
+  handle->socket = socket;
+
+  if (family == AF_INET6) {
+    handle->flags |= UV_HANDLE_IPV6;
+  } else {
+    assert(!(handle->flags & UV_HANDLE_IPV6));
+  }
+
+  return 0;
+}
+
+
+int uv_tcp_init_ex(uv_loop_t* loop, uv_tcp_t* handle, unsigned int flags) {
+  int domain;
+
+  /* Use the lower 8 bits for the domain */
+  domain = flags & 0xFF;
+  if (domain != AF_INET && domain != AF_INET6 && domain != AF_UNSPEC)
+    return UV_EINVAL;
+
+  if (flags & ~0xFF)
+    return UV_EINVAL;
+
+  uv__stream_init(loop, (uv_stream_t*) handle, UV_TCP);
+  handle->tcp.serv.accept_reqs = NULL;
+  handle->tcp.serv.pending_accepts = NULL;
+  handle->socket = INVALID_SOCKET;
+  handle->reqs_pending = 0;
+  handle->tcp.serv.func_acceptex = NULL;
+  handle->tcp.conn.func_connectex = NULL;
+  handle->tcp.serv.processed_accepts = 0;
+  handle->delayed_error = 0;
+
+  /* If anything fails beyond this point we need to remove the handle from
+   * the handle queue, since it was added by uv__handle_init in uv__stream_init.
+   */
+
+  if (domain != AF_UNSPEC) {
+    SOCKET sock;
+    DWORD err;
+
+    sock = socket(domain, SOCK_STREAM, 0);
+    if (sock == INVALID_SOCKET) {
+      err = WSAGetLastError();
+      uv__queue_remove(&handle->handle_queue);
+      return uv_translate_sys_error(err);
+    }
+
+    err = uv__tcp_set_socket(handle->loop, handle, sock, domain, 0);
+    if (err) {
+      closesocket(sock);
+      uv__queue_remove(&handle->handle_queue);
+      return uv_translate_sys_error(err);
+    }
+
+  }
+
+  return 0;
+}
+
+
+int uv_tcp_init(uv_loop_t* loop, uv_tcp_t* handle) {
+  return uv_tcp_init_ex(loop, handle, AF_UNSPEC);
+}
+
+
+void uv__process_tcp_shutdown_req(uv_loop_t* loop, uv_tcp_t* stream, uv_shutdown_t *req) {
+  int err;
+
+  assert(req);
+  assert(stream->stream.conn.write_reqs_pending == 0);
+  assert(!(stream->flags & UV_HANDLE_SHUT));
+  assert(stream->flags & UV_HANDLE_CONNECTION);
+
+  stream->stream.conn.shutdown_req = NULL;
+  UNREGISTER_HANDLE_REQ(loop, stream);
+
+  err = 0;
+  if (stream->flags & UV_HANDLE_CLOSING)
+   /* The user destroyed the stream before we got to do the shutdown. */
+    err = UV_ECANCELED;
+  else if (shutdown(stream->socket, SD_SEND) == SOCKET_ERROR)
+    err = uv_translate_sys_error(WSAGetLastError());
+  else /* Success. */
+    stream->flags |= UV_HANDLE_SHUT;
+
+  if (req->cb)
+    req->cb(req, err);
+
+  DECREASE_PENDING_REQ_COUNT(stream);
+}
+
+
+void uv__tcp_endgame(uv_loop_t* loop, uv_tcp_t* handle) {
+  unsigned int i;
+  uv_tcp_accept_t* req;
+
+  assert(handle->flags & UV_HANDLE_CLOSING);
+  assert(handle->reqs_pending == 0);
+  assert(!(handle->flags & UV_HANDLE_CLOSED));
+  assert(handle->socket == INVALID_SOCKET);
+
+  if (!(handle->flags & UV_HANDLE_CONNECTION) && handle->tcp.serv.accept_reqs) {
+    if (handle->flags & UV_HANDLE_EMULATE_IOCP) {
+      for (i = 0; i < uv_simultaneous_server_accepts; i++) {
+        req = &handle->tcp.serv.accept_reqs[i];
+        if (req->wait_handle != INVALID_HANDLE_VALUE) {
+          UnregisterWait(req->wait_handle);
+          req->wait_handle = INVALID_HANDLE_VALUE;
+        }
+        if (req->event_handle != NULL) {
+          CloseHandle(req->event_handle);
+          req->event_handle = NULL;
+        }
+      }
+    }
+
+    uv__free(handle->tcp.serv.accept_reqs);
+    handle->tcp.serv.accept_reqs = NULL;
+  }
+
+  if (handle->flags & UV_HANDLE_CONNECTION &&
+      handle->flags & UV_HANDLE_EMULATE_IOCP) {
+    if (handle->read_req.wait_handle != INVALID_HANDLE_VALUE) {
+      UnregisterWait(handle->read_req.wait_handle);
+      handle->read_req.wait_handle = INVALID_HANDLE_VALUE;
+    }
+    if (handle->read_req.event_handle != NULL) {
+      CloseHandle(handle->read_req.event_handle);
+      handle->read_req.event_handle = NULL;
+    }
+  }
+
+  uv__handle_close(handle);
+}
+
+
+/* Unlike on Unix, here we don't set SO_REUSEADDR, because it doesn't just
+ * allow binding to addresses that are in use by sockets in TIME_WAIT, it
+ * effectively allows 'stealing' a port which is in use by another application.
+ *
+ * SO_EXCLUSIVEADDRUSE is also not good here because it does check all sockets,
+ * regardless of state, so we'd get an error even if the port is in use by a
+ * socket in TIME_WAIT state.
+ *
+ * See issue #1360.
+ *
+ */
+static int uv__tcp_try_bind(uv_tcp_t* handle,
+                            const struct sockaddr* addr,
+                            unsigned int addrlen,
+                            unsigned int flags) {
+  DWORD err;
+  int r;
+
+  /* There is no SO_REUSEPORT on Windows, Windows only knows SO_REUSEADDR.
+   * so we just return an error directly when UV_TCP_REUSEPORT is requested
+   * for binding the socket. */
+  if (flags & UV_TCP_REUSEPORT)
+    return ERROR_NOT_SUPPORTED;
+
+  if (handle->socket == INVALID_SOCKET) {
+    SOCKET sock;
+
+    /* Cannot set IPv6-only mode on non-IPv6 socket. */
+    if ((flags & UV_TCP_IPV6ONLY) && addr->sa_family != AF_INET6)
+      return ERROR_INVALID_PARAMETER;
+
+    sock = socket(addr->sa_family, SOCK_STREAM, 0);
+    if (sock == INVALID_SOCKET) {
+      return WSAGetLastError();
+    }
+
+    err = uv__tcp_set_socket(handle->loop, handle, sock, addr->sa_family, 0);
+    if (err) {
+      closesocket(sock);
+      return err;
+    }
+  }
+
+#ifdef IPV6_V6ONLY
+  if (addr->sa_family == AF_INET6) {
+    int on;
+
+    on = (flags & UV_TCP_IPV6ONLY) != 0;
+
+    /* TODO: how to handle errors? This may fail if there is no ipv4 stack
+     * available, or when run on XP/2003 which have no support for dualstack
+     * sockets. For now we're silently ignoring the error. */
+    setsockopt(handle->socket,
+               IPPROTO_IPV6,
+               IPV6_V6ONLY,
+               (const char*)&on,
+               sizeof on);
+  }
+#endif
+
+  r = bind(handle->socket, addr, addrlen);
+
+  if (r == SOCKET_ERROR) {
+    err = WSAGetLastError();
+    if (err == WSAEADDRINUSE) {
+      /* Some errors are not to be reported until connect() or listen() */
+      handle->delayed_error = err;
+    } else {
+      return err;
+    }
+  }
+
+  handle->flags |= UV_HANDLE_BOUND;
+
+  return 0;
+}
+
+
+static void CALLBACK post_completion(void* context, BOOLEAN timed_out) {
+  uv_req_t* req;
+  uv_tcp_t* handle;
+
+  req = (uv_req_t*) context;
+  assert(req != NULL);
+  handle = (uv_tcp_t*)req->data;
+  assert(handle != NULL);
+  assert(!timed_out);
+
+  if (!PostQueuedCompletionStatus(handle->loop->iocp,
+                                  req->u.io.overlapped.InternalHigh,
+                                  0,
+                                  &req->u.io.overlapped)) {
+    uv_fatal_error(GetLastError(), "PostQueuedCompletionStatus");
+  }
+}
+
+
+static void CALLBACK post_write_completion(void* context, BOOLEAN timed_out) {
+  uv_write_t* req;
+  uv_tcp_t* handle;
+
+  req = (uv_write_t*) context;
+  assert(req != NULL);
+  handle = (uv_tcp_t*)req->handle;
+  assert(handle != NULL);
+  assert(!timed_out);
+
+  if (!PostQueuedCompletionStatus(handle->loop->iocp,
+                                  req->u.io.overlapped.InternalHigh,
+                                  0,
+                                  &req->u.io.overlapped)) {
+    uv_fatal_error(GetLastError(), "PostQueuedCompletionStatus");
+  }
+}
+
+
+static void uv__tcp_queue_accept(uv_tcp_t* handle, uv_tcp_accept_t* req) {
+  uv_loop_t* loop = handle->loop;
+  BOOL success;
+  DWORD bytes;
+  SOCKET accept_socket;
+  short family;
+
+  assert(handle->flags & UV_HANDLE_LISTENING);
+  assert(req->accept_socket == INVALID_SOCKET);
+
+  /* choose family and extension function */
+  if (handle->flags & UV_HANDLE_IPV6) {
+    family = AF_INET6;
+  } else {
+    family = AF_INET;
+  }
+
+  /* Open a socket for the accepted connection. */
+  accept_socket = socket(family, SOCK_STREAM, 0);
+  if (accept_socket == INVALID_SOCKET) {
+    SET_REQ_ERROR(req, WSAGetLastError());
+    uv__insert_pending_req(loop, (uv_req_t*)req);
+    handle->reqs_pending++;
+    return;
+  }
+
+  /* Make the socket non-inheritable */
+  if (!SetHandleInformation((HANDLE) accept_socket, HANDLE_FLAG_INHERIT, 0)) {
+    SET_REQ_ERROR(req, GetLastError());
+    uv__insert_pending_req(loop, (uv_req_t*)req);
+    handle->reqs_pending++;
+    closesocket(accept_socket);
+    return;
+  }
+
+  /* Prepare the overlapped structure. */
+  memset(&(req->u.io.overlapped), 0, sizeof(req->u.io.overlapped));
+  if (handle->flags & UV_HANDLE_EMULATE_IOCP) {
+    assert(req->event_handle != NULL);
+    req->u.io.overlapped.hEvent = (HANDLE) ((ULONG_PTR) req->event_handle | 1);
+  }
+
+  success = handle->tcp.serv.func_acceptex(handle->socket,
+                                          accept_socket,
+                                          (void*)req->accept_buffer,
+                                          0,
+                                          sizeof(struct sockaddr_storage),
+                                          sizeof(struct sockaddr_storage),
+                                          &bytes,
+                                          &req->u.io.overlapped);
+
+  if (UV_SUCCEEDED_WITHOUT_IOCP(success)) {
+    /* Process the req without IOCP. */
+    req->accept_socket = accept_socket;
+    handle->reqs_pending++;
+    uv__insert_pending_req(loop, (uv_req_t*)req);
+  } else if (UV_SUCCEEDED_WITH_IOCP(success)) {
+    /* The req will be processed with IOCP. */
+    req->accept_socket = accept_socket;
+    handle->reqs_pending++;
+    if (handle->flags & UV_HANDLE_EMULATE_IOCP &&
+        req->wait_handle == INVALID_HANDLE_VALUE &&
+        !RegisterWaitForSingleObject(&req->wait_handle,
+          req->event_handle, post_completion, (void*) req,
+          INFINITE, WT_EXECUTEINWAITTHREAD)) {
+      SET_REQ_ERROR(req, GetLastError());
+      uv__insert_pending_req(loop, (uv_req_t*)req);
+    }
+  } else {
+    /* Make this req pending reporting an error. */
+    SET_REQ_ERROR(req, WSAGetLastError());
+    uv__insert_pending_req(loop, (uv_req_t*)req);
+    handle->reqs_pending++;
+    /* Destroy the preallocated client socket. */
+    closesocket(accept_socket);
+    /* Destroy the event handle */
+    if (handle->flags & UV_HANDLE_EMULATE_IOCP) {
+      CloseHandle(req->event_handle);
+      req->event_handle = NULL;
+    }
+  }
+}
+
+
+static void uv__tcp_queue_read(uv_loop_t* loop, uv_tcp_t* handle) {
+  uv_read_t* req;
+  uv_buf_t buf;
+  int result;
+  DWORD bytes, flags;
+
+  assert(handle->flags & UV_HANDLE_READING);
+  assert(!(handle->flags & UV_HANDLE_READ_PENDING));
+
+  req = &handle->read_req;
+  memset(&req->u.io.overlapped, 0, sizeof(req->u.io.overlapped));
+
+  handle->flags |= UV_HANDLE_ZERO_READ;
+  buf.base = (char*) &uv_zero_;
+  buf.len = 0;
+
+  /* Prepare the overlapped structure. */
+  memset(&(req->u.io.overlapped), 0, sizeof(req->u.io.overlapped));
+  if (handle->flags & UV_HANDLE_EMULATE_IOCP) {
+    assert(req->event_handle != NULL);
+    req->u.io.overlapped.hEvent = (HANDLE) ((ULONG_PTR) req->event_handle | 1);
+  }
+
+  flags = 0;
+  result = WSARecv(handle->socket,
+                   (WSABUF*)&buf,
+                   1,
+                   &bytes,
+                   &flags,
+                   &req->u.io.overlapped,
+                   NULL);
+
+  handle->flags |= UV_HANDLE_READ_PENDING;
+  handle->reqs_pending++;
+
+  if (UV_SUCCEEDED_WITHOUT_IOCP(result == 0)) {
+    /* Process the req without IOCP. */
+    req->u.io.overlapped.InternalHigh = bytes;
+    uv__insert_pending_req(loop, (uv_req_t*)req);
+  } else if (UV_SUCCEEDED_WITH_IOCP(result == 0)) {
+    /* The req will be processed with IOCP. */
+    if (handle->flags & UV_HANDLE_EMULATE_IOCP &&
+        req->wait_handle == INVALID_HANDLE_VALUE &&
+        !RegisterWaitForSingleObject(&req->wait_handle,
+          req->event_handle, post_completion, (void*) req,
+          INFINITE, WT_EXECUTEINWAITTHREAD)) {
+      SET_REQ_ERROR(req, GetLastError());
+      uv__insert_pending_req(loop, (uv_req_t*)req);
+    }
+  } else {
+    /* Make this req pending reporting an error. */
+    SET_REQ_ERROR(req, WSAGetLastError());
+    uv__insert_pending_req(loop, (uv_req_t*)req);
+  }
+}
+
+
+int uv_tcp_close_reset(uv_tcp_t* handle, uv_close_cb close_cb) {
+  struct linger l = { 1, 0 };
+
+  /* Disallow setting SO_LINGER to zero due to some platform inconsistencies */
+  if (uv__is_stream_shutting(handle))
+    return UV_EINVAL;
+
+  if (0 != setsockopt(handle->socket, SOL_SOCKET, SO_LINGER, (const char*)&l, sizeof(l)))
+    return uv_translate_sys_error(WSAGetLastError());
+
+  uv_close((uv_handle_t*) handle, close_cb);
+  return 0;
+}
+
+
+int uv__tcp_listen(uv_tcp_t* handle, int backlog, uv_connection_cb cb) {
+  unsigned int i, simultaneous_accepts;
+  uv_tcp_accept_t* req;
+  int err;
+
+  assert(backlog > 0);
+
+  if (handle->flags & UV_HANDLE_LISTENING) {
+    handle->stream.serv.connection_cb = cb;
+  }
+
+  if (handle->flags & UV_HANDLE_READING) {
+    return WSAEISCONN;
+  }
+
+  if (handle->delayed_error) {
+    return handle->delayed_error;
+  }
+
+  if (!(handle->flags & UV_HANDLE_BOUND)) {
+    err = uv__tcp_try_bind(handle,
+                           (const struct sockaddr*) &uv_addr_ip4_any_,
+                           sizeof(uv_addr_ip4_any_),
+                           0);
+    if (err)
+      return err;
+    if (handle->delayed_error)
+      return handle->delayed_error;
+  }
+
+  if (!handle->tcp.serv.func_acceptex) {
+    if (!uv__get_acceptex_function(handle->socket, &handle->tcp.serv.func_acceptex)) {
+      return WSAEAFNOSUPPORT;
+    }
+  }
+
+  /* If this flag is set, we already made this listen call in xfer. */
+  if (!(handle->flags & UV_HANDLE_SHARED_TCP_SOCKET) &&
+      listen(handle->socket, backlog) == SOCKET_ERROR) {
+    return WSAGetLastError();
+  }
+
+  handle->flags |= UV_HANDLE_LISTENING;
+  handle->stream.serv.connection_cb = cb;
+  INCREASE_ACTIVE_COUNT(loop, handle);
+
+  simultaneous_accepts = handle->flags & UV_HANDLE_TCP_SINGLE_ACCEPT ? 1
+    : uv_simultaneous_server_accepts;
+
+  if (handle->tcp.serv.accept_reqs == NULL) {
+    handle->tcp.serv.accept_reqs =
+      uv__malloc(uv_simultaneous_server_accepts * sizeof(uv_tcp_accept_t));
+    if (!handle->tcp.serv.accept_reqs) {
+      uv_fatal_error(ERROR_OUTOFMEMORY, "uv__malloc");
+    }
+
+    for (i = 0; i < simultaneous_accepts; i++) {
+      req = &handle->tcp.serv.accept_reqs[i];
+      UV_REQ_INIT(req, UV_ACCEPT);
+      req->accept_socket = INVALID_SOCKET;
+      req->data = handle;
+
+      req->wait_handle = INVALID_HANDLE_VALUE;
+      if (handle->flags & UV_HANDLE_EMULATE_IOCP) {
+        req->event_handle = CreateEvent(NULL, 0, 0, NULL);
+        if (req->event_handle == NULL) {
+          uv_fatal_error(GetLastError(), "CreateEvent");
+        }
+      } else {
+        req->event_handle = NULL;
+      }
+
+      uv__tcp_queue_accept(handle, req);
+    }
+
+    /* Initialize other unused requests too, because uv_tcp_endgame doesn't
+     * know how many requests were initialized, so it will try to clean up
+     * {uv_simultaneous_server_accepts} requests. */
+    for (i = simultaneous_accepts; i < uv_simultaneous_server_accepts; i++) {
+      req = &handle->tcp.serv.accept_reqs[i];
+      UV_REQ_INIT(req, UV_ACCEPT);
+      req->accept_socket = INVALID_SOCKET;
+      req->data = handle;
+      req->wait_handle = INVALID_HANDLE_VALUE;
+      req->event_handle = NULL;
+    }
+  }
+
+  return 0;
+}
+
+
+int uv__tcp_accept(uv_tcp_t* server, uv_tcp_t* client) {
+  int err = 0;
+  int family;
+
+  uv_tcp_accept_t* req = server->tcp.serv.pending_accepts;
+
+  if (!req) {
+    /* No valid connections found, so we error out. */
+    return WSAEWOULDBLOCK;
+  }
+
+  if (req->accept_socket == INVALID_SOCKET) {
+    return WSAENOTCONN;
+  }
+
+  if (server->flags & UV_HANDLE_IPV6) {
+    family = AF_INET6;
+  } else {
+    family = AF_INET;
+  }
+
+  err = uv__tcp_set_socket(client->loop,
+                          client,
+                          req->accept_socket,
+                          family,
+                          0);
+  if (err) {
+    closesocket(req->accept_socket);
+  } else {
+    uv__connection_init((uv_stream_t*) client);
+    /* AcceptEx() implicitly binds the accepted socket. */
+    client->flags |= UV_HANDLE_BOUND | UV_HANDLE_READABLE | UV_HANDLE_WRITABLE;
+  }
+
+  /* Prepare the req to pick up a new connection */
+  server->tcp.serv.pending_accepts = req->next_pending;
+  req->next_pending = NULL;
+  req->accept_socket = INVALID_SOCKET;
+
+  if (!(server->flags & UV_HANDLE_CLOSING)) {
+    /* Check if we're in a middle of changing the number of pending accepts. */
+    if (!(server->flags & UV_HANDLE_TCP_ACCEPT_STATE_CHANGING)) {
+      uv__tcp_queue_accept(server, req);
+    } else {
+      /* We better be switching to a single pending accept. */
+      assert(server->flags & UV_HANDLE_TCP_SINGLE_ACCEPT);
+
+      server->tcp.serv.processed_accepts++;
+
+      if (server->tcp.serv.processed_accepts >= uv_simultaneous_server_accepts) {
+        server->tcp.serv.processed_accepts = 0;
+        /*
+         * All previously queued accept requests are now processed.
+         * We now switch to queueing just a single accept.
+         */
+        uv__tcp_queue_accept(server, &server->tcp.serv.accept_reqs[0]);
+        server->flags &= ~UV_HANDLE_TCP_ACCEPT_STATE_CHANGING;
+        server->flags |= UV_HANDLE_TCP_SINGLE_ACCEPT;
+      }
+    }
+  }
+
+  return err;
+}
+
+
+int uv__tcp_read_start(uv_tcp_t* handle, uv_alloc_cb alloc_cb,
+    uv_read_cb read_cb) {
+  uv_loop_t* loop = handle->loop;
+
+  handle->flags |= UV_HANDLE_READING;
+  handle->read_cb = read_cb;
+  handle->alloc_cb = alloc_cb;
+  INCREASE_ACTIVE_COUNT(loop, handle);
+
+  /* If reading was stopped and then started again, there could still be a read
+   * request pending. */
+  if (!(handle->flags & UV_HANDLE_READ_PENDING)) {
+    if (handle->flags & UV_HANDLE_EMULATE_IOCP &&
+        handle->read_req.event_handle == NULL) {
+      handle->read_req.event_handle = CreateEvent(NULL, 0, 0, NULL);
+      if (handle->read_req.event_handle == NULL) {
+        uv_fatal_error(GetLastError(), "CreateEvent");
+      }
+    }
+    uv__tcp_queue_read(loop, handle);
+  }
+
+  return 0;
+}
+
+static int uv__is_loopback(const struct sockaddr_storage* storage) {
+  const struct sockaddr_in* in4;
+  const struct sockaddr_in6* in6;
+  int i;
+
+  if (storage->ss_family == AF_INET) {
+    in4 = (const struct sockaddr_in*) storage;
+    return in4->sin_addr.S_un.S_un_b.s_b1 == 127;
+  }
+  if (storage->ss_family == AF_INET6) {
+    in6 = (const struct sockaddr_in6*) storage;
+    for (i = 0; i < 7; ++i) {
+      if (in6->sin6_addr.u.Word[i] != 0)
+        return 0;
+    }
+    return in6->sin6_addr.u.Word[7] == htons(1);
+  }
+  return 0;
+}
+
+// Check if Windows version is 10.0.16299 or later
+static int uv__is_fast_loopback_fail_supported(void) {
+  OSVERSIONINFOW os_info;
+  if (!pRtlGetVersion)
+    return 0;
+  pRtlGetVersion(&os_info);
+  if (os_info.dwMajorVersion < 10)
+    return 0;
+  if (os_info.dwMajorVersion > 10)
+    return 1;
+  if (os_info.dwMinorVersion > 0)
+    return 1;
+  return os_info.dwBuildNumber >= 16299;
+}
+
+static int uv__tcp_try_connect(uv_connect_t* req,
+                              uv_tcp_t* handle,
+                              const struct sockaddr* addr,
+                              unsigned int addrlen,
+                              uv_connect_cb cb) {
+  uv_loop_t* loop = handle->loop;
+  TCP_INITIAL_RTO_PARAMETERS retransmit_ioctl;
+  const struct sockaddr* bind_addr;
+  struct sockaddr_storage converted;
+  BOOL success;
+  DWORD bytes;
+  int err;
+
+  err = uv__convert_to_localhost_if_unspecified(addr, &converted);
+  if (err)
+    return err;
+
+  if (handle->delayed_error != 0)
+    goto out;
+
+  if (!(handle->flags & UV_HANDLE_BOUND)) {
+    if (addrlen == sizeof(uv_addr_ip4_any_)) {
+      bind_addr = (const struct sockaddr*) &uv_addr_ip4_any_;
+    } else if (addrlen == sizeof(uv_addr_ip6_any_)) {
+      bind_addr = (const struct sockaddr*) &uv_addr_ip6_any_;
+    } else {
+      abort();
+    }
+    err = uv__tcp_try_bind(handle, bind_addr, addrlen, 0);
+    if (err)
+      return err;
+    if (handle->delayed_error != 0)
+      goto out;
+  }
+
+  if (!handle->tcp.conn.func_connectex) {
+    if (!uv__get_connectex_function(handle->socket, &handle->tcp.conn.func_connectex)) {
+      return WSAEAFNOSUPPORT;
+    }
+  }
+
+  /* This makes connect() fail instantly if the target port on the localhost
+   * is not reachable, instead of waiting for 2s. We do not care if this fails.
+   * This only works on Windows version 10.0.16299 and later.
+   */
+  if (uv__is_fast_loopback_fail_supported() && uv__is_loopback(&converted)) {
+    memset(&retransmit_ioctl, 0, sizeof(retransmit_ioctl));
+    retransmit_ioctl.Rtt = TCP_INITIAL_RTO_NO_SYN_RETRANSMISSIONS;
+    retransmit_ioctl.MaxSynRetransmissions = TCP_INITIAL_RTO_NO_SYN_RETRANSMISSIONS;
+    WSAIoctl(handle->socket,
+             SIO_TCP_INITIAL_RTO,
+             &retransmit_ioctl,
+             sizeof(retransmit_ioctl),
+             NULL,
+             0,
+             &bytes,
+             NULL,
+             NULL);
+  }
+
+out:
+
+  UV_REQ_INIT(req, UV_CONNECT);
+  req->handle = (uv_stream_t*) handle;
+  req->cb = cb;
+  memset(&req->u.io.overlapped, 0, sizeof(req->u.io.overlapped));
+
+  if (handle->delayed_error != 0) {
+    /* Process the req without IOCP. */
+    handle->reqs_pending++;
+    REGISTER_HANDLE_REQ(loop, handle);
+    uv__insert_pending_req(loop, (uv_req_t*)req);
+    return 0;
+  }
+
+  success = handle->tcp.conn.func_connectex(handle->socket,
+                                            (const struct sockaddr*) &converted,
+                                            addrlen,
+                                            NULL,
+                                            0,
+                                            &bytes,
+                                            &req->u.io.overlapped);
+
+  if (UV_SUCCEEDED_WITHOUT_IOCP(success)) {
+    /* Process the req without IOCP. */
+    handle->reqs_pending++;
+    REGISTER_HANDLE_REQ(loop, handle);
+    uv__insert_pending_req(loop, (uv_req_t*)req);
+  } else if (UV_SUCCEEDED_WITH_IOCP(success)) {
+    /* The req will be processed with IOCP. */
+    handle->reqs_pending++;
+    REGISTER_HANDLE_REQ(loop, handle);
+  } else {
+    return WSAGetLastError();
+  }
+
+  return 0;
+}
+
+
+int uv_tcp_getsockname(const uv_tcp_t* handle,
+                       struct sockaddr* name,
+                       int* namelen) {
+
+  return uv__getsockpeername((const uv_handle_t*) handle,
+                             getsockname,
+                             name,
+                             namelen,
+                             handle->delayed_error);
+}
+
+
+int uv_tcp_getpeername(const uv_tcp_t* handle,
+                       struct sockaddr* name,
+                       int* namelen) {
+
+  return uv__getsockpeername((const uv_handle_t*) handle,
+                             getpeername,
+                             name,
+                             namelen,
+                             handle->delayed_error);
+}
+
+
+int uv__tcp_write(uv_loop_t* loop,
+                 uv_write_t* req,
+                 uv_tcp_t* handle,
+                 const uv_buf_t bufs[],
+                 unsigned int nbufs,
+                 uv_write_cb cb) {
+  int result;
+  DWORD bytes;
+
+  UV_REQ_INIT(req, UV_WRITE);
+  req->handle = (uv_stream_t*) handle;
+  req->cb = cb;
+
+  /* Prepare the overlapped structure. */
+  memset(&(req->u.io.overlapped), 0, sizeof(req->u.io.overlapped));
+  if (handle->flags & UV_HANDLE_EMULATE_IOCP) {
+    req->event_handle = CreateEvent(NULL, 0, 0, NULL);
+    if (req->event_handle == NULL) {
+      uv_fatal_error(GetLastError(), "CreateEvent");
+    }
+    req->u.io.overlapped.hEvent = (HANDLE) ((ULONG_PTR) req->event_handle | 1);
+    req->wait_handle = INVALID_HANDLE_VALUE;
+  }
+
+  result = WSASend(handle->socket,
+                   (WSABUF*) bufs,
+                   nbufs,
+                   &bytes,
+                   0,
+                   &req->u.io.overlapped,
+                   NULL);
+
+  if (UV_SUCCEEDED_WITHOUT_IOCP(result == 0)) {
+    /* Request completed immediately. */
+    req->u.io.queued_bytes = 0;
+    handle->reqs_pending++;
+    handle->stream.conn.write_reqs_pending++;
+    REGISTER_HANDLE_REQ(loop, handle);
+    uv__insert_pending_req(loop, (uv_req_t*) req);
+  } else if (UV_SUCCEEDED_WITH_IOCP(result == 0)) {
+    /* Request queued by the kernel. */
+    req->u.io.queued_bytes = uv__count_bufs(bufs, nbufs);
+    handle->reqs_pending++;
+    handle->stream.conn.write_reqs_pending++;
+    REGISTER_HANDLE_REQ(loop, handle);
+    handle->write_queue_size += req->u.io.queued_bytes;
+    if (handle->flags & UV_HANDLE_EMULATE_IOCP &&
+        !RegisterWaitForSingleObject(&req->wait_handle,
+          req->event_handle, post_write_completion, (void*) req,
+          INFINITE, WT_EXECUTEINWAITTHREAD | WT_EXECUTEONLYONCE)) {
+      SET_REQ_ERROR(req, GetLastError());
+      uv__insert_pending_req(loop, (uv_req_t*)req);
+    }
+  } else {
+    /* Send failed due to an error, report it later */
+    req->u.io.queued_bytes = 0;
+    handle->reqs_pending++;
+    handle->stream.conn.write_reqs_pending++;
+    REGISTER_HANDLE_REQ(loop, handle);
+    SET_REQ_ERROR(req, WSAGetLastError());
+    uv__insert_pending_req(loop, (uv_req_t*) req);
+  }
+
+  return 0;
+}
+
+
+int uv__tcp_try_write(uv_tcp_t* handle,
+                     const uv_buf_t bufs[],
+                     unsigned int nbufs) {
+  int result;
+  DWORD bytes;
+
+  if (handle->stream.conn.write_reqs_pending > 0)
+    return UV_EAGAIN;
+
+  result = WSASend(handle->socket,
+                   (WSABUF*) bufs,
+                   nbufs,
+                   &bytes,
+                   0,
+                   NULL,
+                   NULL);
+
+  if (result == SOCKET_ERROR)
+    return uv_translate_sys_error(WSAGetLastError());
+  else
+    return bytes;
+}
+
+
+void uv__process_tcp_read_req(uv_loop_t* loop, uv_tcp_t* handle,
+    uv_req_t* req) {
+  DWORD bytes, flags, err;
+  uv_buf_t buf;
+  int count;
+
+  assert(handle->type == UV_TCP);
+
+  handle->flags &= ~UV_HANDLE_READ_PENDING;
+
+  if (!REQ_SUCCESS(req)) {
+    /* An error occurred doing the read. */
+    if ((handle->flags & UV_HANDLE_READING) ||
+        !(handle->flags & UV_HANDLE_ZERO_READ)) {
+      handle->flags &= ~UV_HANDLE_READING;
+      DECREASE_ACTIVE_COUNT(loop, handle);
+      buf = (handle->flags & UV_HANDLE_ZERO_READ) ?
+            uv_buf_init(NULL, 0) : handle->tcp.conn.read_buffer;
+
+      err = GET_REQ_SOCK_ERROR(req);
+
+      if (err == WSAECONNABORTED) {
+        /* Turn WSAECONNABORTED into UV_ECONNRESET to be consistent with Unix.
+         */
+        err = WSAECONNRESET;
+      }
+      handle->flags &= ~(UV_HANDLE_READABLE | UV_HANDLE_WRITABLE);
+
+      handle->read_cb((uv_stream_t*)handle,
+                      uv_translate_sys_error(err),
+                      &buf);
+    }
+  } else {
+    if (!(handle->flags & UV_HANDLE_ZERO_READ)) {
+      /* The read was done with a non-zero buffer length. */
+      if (req->u.io.overlapped.InternalHigh > 0) {
+        /* Successful read */
+        handle->read_cb((uv_stream_t*)handle,
+                        req->u.io.overlapped.InternalHigh,
+                        &handle->tcp.conn.read_buffer);
+        /* Read again only if bytes == buf.len */
+        if (req->u.io.overlapped.InternalHigh < handle->tcp.conn.read_buffer.len) {
+          goto done;
+        }
+      } else {
+        /* Connection closed */
+        if (handle->flags & UV_HANDLE_READING) {
+          handle->flags &= ~UV_HANDLE_READING;
+          DECREASE_ACTIVE_COUNT(loop, handle);
+        }
+
+        buf.base = 0;
+        buf.len = 0;
+        handle->read_cb((uv_stream_t*)handle, UV_EOF, &handle->tcp.conn.read_buffer);
+        goto done;
+      }
+    }
+
+    /* Do nonblocking reads until the buffer is empty */
+    count = 32;
+    while ((handle->flags & UV_HANDLE_READING) && (count-- > 0)) {
+      buf = uv_buf_init(NULL, 0);
+      handle->alloc_cb((uv_handle_t*) handle, 65536, &buf);
+      if (buf.base == NULL || buf.len == 0) {
+        handle->read_cb((uv_stream_t*) handle, UV_ENOBUFS, &buf);
+        break;
+      }
+      assert(buf.base != NULL);
+
+      flags = 0;
+      if (WSARecv(handle->socket,
+                  (WSABUF*)&buf,
+                  1,
+                  &bytes,
+                  &flags,
+                  NULL,
+                  NULL) != SOCKET_ERROR) {
+        if (bytes > 0) {
+          /* Successful read */
+          handle->read_cb((uv_stream_t*)handle, bytes, &buf);
+          /* Read again only if bytes == buf.len */
+          if (bytes < buf.len) {
+            break;
+          }
+        } else {
+          /* Connection closed */
+          handle->flags &= ~UV_HANDLE_READING;
+          DECREASE_ACTIVE_COUNT(loop, handle);
+
+          handle->read_cb((uv_stream_t*)handle, UV_EOF, &buf);
+          break;
+        }
+      } else {
+        err = WSAGetLastError();
+        if (err == WSAEWOULDBLOCK) {
+          /* Read buffer was completely empty, report a 0-byte read. */
+          handle->read_cb((uv_stream_t*)handle, 0, &buf);
+        } else {
+          /* Ouch! serious error. */
+          handle->flags &= ~UV_HANDLE_READING;
+          DECREASE_ACTIVE_COUNT(loop, handle);
+
+          if (err == WSAECONNABORTED) {
+            /* Turn WSAECONNABORTED into UV_ECONNRESET to be consistent with
+             * Unix. */
+            err = WSAECONNRESET;
+          }
+          handle->flags &= ~(UV_HANDLE_READABLE | UV_HANDLE_WRITABLE);
+
+          handle->read_cb((uv_stream_t*)handle,
+                          uv_translate_sys_error(err),
+                          &buf);
+        }
+        break;
+      }
+    }
+
+done:
+    /* Post another read if still reading and not closing. */
+    if ((handle->flags & UV_HANDLE_READING) &&
+        !(handle->flags & UV_HANDLE_READ_PENDING)) {
+      uv__tcp_queue_read(loop, handle);
+    }
+  }
+
+  DECREASE_PENDING_REQ_COUNT(handle);
+}
+
+
+void uv__process_tcp_write_req(uv_loop_t* loop, uv_tcp_t* handle,
+    uv_write_t* req) {
+  int err;
+
+  assert(handle->type == UV_TCP);
+
+  assert(handle->write_queue_size >= req->u.io.queued_bytes);
+  handle->write_queue_size -= req->u.io.queued_bytes;
+
+  UNREGISTER_HANDLE_REQ(loop, handle);
+
+  if (handle->flags & UV_HANDLE_EMULATE_IOCP) {
+    if (req->wait_handle != INVALID_HANDLE_VALUE) {
+      UnregisterWait(req->wait_handle);
+      req->wait_handle = INVALID_HANDLE_VALUE;
+    }
+    if (req->event_handle != NULL) {
+      CloseHandle(req->event_handle);
+      req->event_handle = NULL;
+    }
+  }
+
+  if (req->cb) {
+    err = uv_translate_sys_error(GET_REQ_SOCK_ERROR(req));
+    if (err == UV_ECONNABORTED) {
+      /* use UV_ECANCELED for consistency with Unix */
+      err = UV_ECANCELED;
+    }
+    req->cb(req, err);
+  }
+
+  handle->stream.conn.write_reqs_pending--;
+  if (handle->stream.conn.write_reqs_pending == 0) {
+    if (handle->flags & UV_HANDLE_CLOSING) {
+      closesocket(handle->socket);
+      handle->socket = INVALID_SOCKET;
+    }
+    if (uv__is_stream_shutting(handle))
+      uv__process_tcp_shutdown_req(loop,
+                                   handle,
+                                   handle->stream.conn.shutdown_req);
+  }
+
+  DECREASE_PENDING_REQ_COUNT(handle);
+}
+
+
+void uv__process_tcp_accept_req(uv_loop_t* loop, uv_tcp_t* handle,
+    uv_req_t* raw_req) {
+  uv_tcp_accept_t* req = (uv_tcp_accept_t*) raw_req;
+  int err;
+
+  assert(handle->type == UV_TCP);
+
+  /* If handle->accepted_socket is not a valid socket, then uv_queue_accept
+   * must have failed. This is a serious error. We stop accepting connections
+   * and report this error to the connection callback. */
+  if (req->accept_socket == INVALID_SOCKET) {
+    if (handle->flags & UV_HANDLE_LISTENING) {
+      handle->flags &= ~UV_HANDLE_LISTENING;
+      DECREASE_ACTIVE_COUNT(loop, handle);
+      if (handle->stream.serv.connection_cb) {
+        err = GET_REQ_SOCK_ERROR(req);
+        handle->stream.serv.connection_cb((uv_stream_t*)handle,
+                                      uv_translate_sys_error(err));
+      }
+    }
+  } else if (REQ_SUCCESS(req) &&
+      setsockopt(req->accept_socket,
+                  SOL_SOCKET,
+                  SO_UPDATE_ACCEPT_CONTEXT,
+                  (char*)&handle->socket,
+                  sizeof(handle->socket)) == 0) {
+    req->next_pending = handle->tcp.serv.pending_accepts;
+    handle->tcp.serv.pending_accepts = req;
+
+    /* Accept and SO_UPDATE_ACCEPT_CONTEXT were successful. */
+    if (handle->stream.serv.connection_cb) {
+      handle->stream.serv.connection_cb((uv_stream_t*)handle, 0);
+    }
+  } else {
+    /* Error related to accepted socket is ignored because the server socket
+     * may still be healthy. If the server socket is broken uv_queue_accept
+     * will detect it. */
+    closesocket(req->accept_socket);
+    req->accept_socket = INVALID_SOCKET;
+    if (handle->flags & UV_HANDLE_LISTENING) {
+      uv__tcp_queue_accept(handle, req);
+    }
+  }
+
+  DECREASE_PENDING_REQ_COUNT(handle);
+}
+
+
+void uv__process_tcp_connect_req(uv_loop_t* loop, uv_tcp_t* handle,
+    uv_connect_t* req) {
+  int err;
+
+  assert(handle->type == UV_TCP);
+
+  UNREGISTER_HANDLE_REQ(loop, handle);
+
+  err = 0;
+  if (handle->delayed_error) {
+    /* To smooth over the differences between unixes errors that
+     * were reported synchronously on the first connect can be delayed
+     * until the next tick--which is now.
+     */
+    err = handle->delayed_error;
+    handle->delayed_error = 0;
+  } else if (REQ_SUCCESS(req)) {
+    if (handle->flags & UV_HANDLE_CLOSING) {
+      /* use UV_ECANCELED for consistency with Unix */
+      err = ERROR_OPERATION_ABORTED;
+    } else if (setsockopt(handle->socket,
+                          SOL_SOCKET,
+                          SO_UPDATE_CONNECT_CONTEXT,
+                          NULL,
+                          0) == 0) {
+      uv__connection_init((uv_stream_t*)handle);
+      handle->flags |= UV_HANDLE_READABLE | UV_HANDLE_WRITABLE;
+    } else {
+      err = WSAGetLastError();
+    }
+  } else {
+    err = GET_REQ_SOCK_ERROR(req);
+  }
+  req->cb(req, uv_translate_sys_error(err));
+
+  DECREASE_PENDING_REQ_COUNT(handle);
+}
+
+
+int uv__tcp_xfer_export(uv_tcp_t* handle,
+                        int target_pid,
+                        uv__ipc_socket_xfer_type_t* xfer_type,
+                        uv__ipc_socket_xfer_info_t* xfer_info) {
+  if (handle->flags & UV_HANDLE_CONNECTION) {
+    *xfer_type = UV__IPC_SOCKET_XFER_TCP_CONNECTION;
+  } else {
+    *xfer_type = UV__IPC_SOCKET_XFER_TCP_SERVER;
+    /* We're about to share the socket with another process. Because this is a
+     * listening socket, we assume that the other process will be accepting
+     * connections on it. Thus, before sharing the socket with another process,
+     * we call listen here in the parent process. */
+    if (!(handle->flags & UV_HANDLE_LISTENING)) {
+      if (!(handle->flags & UV_HANDLE_BOUND)) {
+        return ERROR_NOT_SUPPORTED;
+      }
+      if (handle->delayed_error == 0 &&
+          listen(handle->socket, SOMAXCONN) == SOCKET_ERROR) {
+        handle->delayed_error = WSAGetLastError();
+      }
+    }
+  }
+
+  if (WSADuplicateSocketW(handle->socket, target_pid, &xfer_info->socket_info))
+    return WSAGetLastError();
+  xfer_info->delayed_error = handle->delayed_error;
+
+  /* Mark the local copy of the handle as 'shared' so we behave in a way that's
+   * friendly to the process(es) that we share the socket with. */
+  handle->flags |= UV_HANDLE_SHARED_TCP_SOCKET;
+
+  return 0;
+}
+
+
+int uv__tcp_xfer_import(uv_tcp_t* tcp,
+                        uv__ipc_socket_xfer_type_t xfer_type,
+                        uv__ipc_socket_xfer_info_t* xfer_info) {
+  int err;
+  SOCKET socket;
+
+  assert(xfer_type == UV__IPC_SOCKET_XFER_TCP_SERVER ||
+         xfer_type == UV__IPC_SOCKET_XFER_TCP_CONNECTION);
+
+  socket = WSASocketW(FROM_PROTOCOL_INFO,
+                      FROM_PROTOCOL_INFO,
+                      FROM_PROTOCOL_INFO,
+                      &xfer_info->socket_info,
+                      0,
+                      WSA_FLAG_OVERLAPPED);
+
+  if (socket == INVALID_SOCKET) {
+    return WSAGetLastError();
+  }
+
+  err = uv__tcp_set_socket(
+      tcp->loop, tcp, socket, xfer_info->socket_info.iAddressFamily, 1);
+  if (err) {
+    closesocket(socket);
+    return err;
+  }
+
+  tcp->delayed_error = xfer_info->delayed_error;
+  tcp->flags |= UV_HANDLE_BOUND | UV_HANDLE_SHARED_TCP_SOCKET;
+
+  if (xfer_type == UV__IPC_SOCKET_XFER_TCP_CONNECTION) {
+    uv__connection_init((uv_stream_t*)tcp);
+    tcp->flags |= UV_HANDLE_READABLE | UV_HANDLE_WRITABLE;
+  }
+
+  return 0;
+}
+
+
+int uv_tcp_nodelay(uv_tcp_t* handle, int enable) {
+  int err;
+
+  if (handle->socket != INVALID_SOCKET) {
+    err = uv__tcp_nodelay(handle, handle->socket, enable);
+    if (err)
+      return uv_translate_sys_error(err);
+  }
+
+  if (enable) {
+    handle->flags |= UV_HANDLE_TCP_NODELAY;
+  } else {
+    handle->flags &= ~UV_HANDLE_TCP_NODELAY;
+  }
+
+  return 0;
+}
+
+
+int uv_tcp_keepalive(uv_tcp_t* handle, int enable, unsigned int delay) {
+  int err;
+
+  if (handle->socket != INVALID_SOCKET) {
+    err = uv__tcp_keepalive(handle, handle->socket, enable, delay);
+    if (err)
+      return uv_translate_sys_error(err);
+  }
+
+  if (enable) {
+    handle->flags |= UV_HANDLE_TCP_KEEPALIVE;
+  } else {
+    handle->flags &= ~UV_HANDLE_TCP_KEEPALIVE;
+  }
+
+  /* TODO: Store delay if handle->socket isn't created yet. */
+
+  return 0;
+}
+
+
+int uv_tcp_simultaneous_accepts(uv_tcp_t* handle, int enable) {
+  if (handle->flags & UV_HANDLE_CONNECTION) {
+    return UV_EINVAL;
+  }
+
+  /* Check if we're already in the desired mode. */
+  if ((enable && !(handle->flags & UV_HANDLE_TCP_SINGLE_ACCEPT)) ||
+      (!enable && handle->flags & UV_HANDLE_TCP_SINGLE_ACCEPT)) {
+    return 0;
+  }
+
+  /* Don't allow switching from single pending accept to many. */
+  if (enable) {
+    return UV_ENOTSUP;
+  }
+
+  /* Check if we're in a middle of changing the number of pending accepts. */
+  if (handle->flags & UV_HANDLE_TCP_ACCEPT_STATE_CHANGING) {
+    return 0;
+  }
+
+  handle->flags |= UV_HANDLE_TCP_SINGLE_ACCEPT;
+
+  /* Flip the changing flag if we have already queued multiple accepts. */
+  if (handle->flags & UV_HANDLE_LISTENING) {
+    handle->flags |= UV_HANDLE_TCP_ACCEPT_STATE_CHANGING;
+  }
+
+  return 0;
+}
+
+
+static void uv__tcp_try_cancel_reqs(uv_tcp_t* tcp) {
+  SOCKET socket;
+  int non_ifs_lsp;
+  int reading;
+  int writing;
+
+  socket = tcp->socket;
+  reading = tcp->flags & UV_HANDLE_READ_PENDING;
+  writing = tcp->stream.conn.write_reqs_pending > 0;
+  if (!reading && !writing)
+    return;
+
+  /* TODO: in libuv v2, keep explicit track of write_reqs, so we can cancel
+   * them each explicitly with CancelIoEx (like unix). */
+  if (reading)
+    CancelIoEx((HANDLE) socket, &tcp->read_req.u.io.overlapped);
+  if (writing)
+    CancelIo((HANDLE) socket);
+
+  /* Check if we have any non-IFS LSPs stacked on top of TCP */
+  non_ifs_lsp = (tcp->flags & UV_HANDLE_IPV6) ? uv_tcp_non_ifs_lsp_ipv6 :
+                                                uv_tcp_non_ifs_lsp_ipv4;
+
+  /* If there are non-ifs LSPs then try to obtain a base handle for the socket.
+   */
+  if (non_ifs_lsp) {
+    DWORD bytes;
+    if (WSAIoctl(socket,
+                 SIO_BASE_HANDLE,
+                 NULL,
+                 0,
+                 &socket,
+                 sizeof socket,
+                 &bytes,
+                 NULL,
+                 NULL) != 0) {
+      /* Failed. We can't do CancelIo. */
+      return;
+    }
+  }
+
+  assert(socket != 0 && socket != INVALID_SOCKET);
+
+  if (socket != tcp->socket) {
+    if (reading)
+      CancelIoEx((HANDLE) socket, &tcp->read_req.u.io.overlapped);
+    if (writing)
+      CancelIo((HANDLE) socket);
+  }
+}
+
+
+void uv__tcp_close(uv_loop_t* loop, uv_tcp_t* tcp) {
+  if (tcp->flags & UV_HANDLE_CONNECTION) {
+    if (tcp->flags & UV_HANDLE_READING) {
+      uv_read_stop((uv_stream_t*) tcp);
+    }
+    uv__tcp_try_cancel_reqs(tcp);
+  } else {
+    if (tcp->tcp.serv.accept_reqs != NULL) {
+      /* First close the incoming sockets to cancel the accept operations before
+       * we free their resources. */
+      unsigned int i;
+      for (i = 0; i < uv_simultaneous_server_accepts; i++) {
+        uv_tcp_accept_t* req = &tcp->tcp.serv.accept_reqs[i];
+        if (req->accept_socket != INVALID_SOCKET) {
+          closesocket(req->accept_socket);
+          req->accept_socket = INVALID_SOCKET;
+        }
+      }
+    }
+    assert(!(tcp->flags & UV_HANDLE_READING));
+  }
+
+  if (tcp->flags & UV_HANDLE_LISTENING) {
+    tcp->flags &= ~UV_HANDLE_LISTENING;
+    DECREASE_ACTIVE_COUNT(loop, tcp);
+  }
+
+  tcp->flags &= ~(UV_HANDLE_READABLE | UV_HANDLE_WRITABLE);
+  uv__handle_closing(tcp);
+
+  /* If any overlapped req failed to cancel, calling `closesocket` now would
+   * cause Win32 to send an RST packet. Try to avoid that for writes, if
+   * possibly applicable, by waiting to process the completion notifications
+   * first (which typically should be cancellations). There's not much we can
+   * do about canceled reads, which also will generate an RST packet. */
+  if (!(tcp->flags & UV_HANDLE_CONNECTION) ||
+      tcp->stream.conn.write_reqs_pending == 0) {
+    closesocket(tcp->socket);
+    tcp->socket = INVALID_SOCKET;
+  }
+
+  if (tcp->reqs_pending == 0)
+    uv__want_endgame(loop, (uv_handle_t*) tcp);
+}
+
+
+int uv_tcp_open(uv_tcp_t* handle, uv_os_sock_t sock) {
+  WSAPROTOCOL_INFOW protocol_info;
+  int opt_len;
+  int err;
+  struct sockaddr_storage saddr;
+  int saddr_len;
+
+  /* Detect the address family of the socket. */
+  opt_len = (int) sizeof protocol_info;
+  if (getsockopt(sock,
+                 SOL_SOCKET,
+                 SO_PROTOCOL_INFOW,
+                 (char*) &protocol_info,
+                 &opt_len) == SOCKET_ERROR) {
+    return uv_translate_sys_error(GetLastError());
+  }
+
+  err = uv__tcp_set_socket(handle->loop,
+                          handle,
+                          sock,
+                          protocol_info.iAddressFamily,
+                          1);
+  if (err) {
+    return uv_translate_sys_error(err);
+  }
+
+  /* Support already active socket. */
+  saddr_len = sizeof(saddr);
+  if (!uv_tcp_getsockname(handle, (struct sockaddr*) &saddr, &saddr_len)) {
+    /* Socket is already bound. */
+    handle->flags |= UV_HANDLE_BOUND;
+    saddr_len = sizeof(saddr);
+    if (!uv_tcp_getpeername(handle, (struct sockaddr*) &saddr, &saddr_len)) {
+      /* Socket is already connected. */
+      uv__connection_init((uv_stream_t*) handle);
+      handle->flags |= UV_HANDLE_READABLE | UV_HANDLE_WRITABLE;
+    }
+  }
+
+  return 0;
+}
+
+
+/* This function is an egress point, i.e. it returns libuv errors rather than
+ * system errors.
+ */
+int uv__tcp_bind(uv_tcp_t* handle,
+                 const struct sockaddr* addr,
+                 unsigned int addrlen,
+                 unsigned int flags) {
+  int err;
+
+  err = uv__tcp_try_bind(handle, addr, addrlen, flags);
+  if (err)
+    return uv_translate_sys_error(err);
+
+  return 0;
+}
+
+
+/* This function is an egress point, i.e. it returns libuv errors rather than
+ * system errors.
+ */
+int uv__tcp_connect(uv_connect_t* req,
+                    uv_tcp_t* handle,
+                    const struct sockaddr* addr,
+                    unsigned int addrlen,
+                    uv_connect_cb cb) {
+  int err;
+
+  err = uv__tcp_try_connect(req, handle, addr, addrlen, cb);
+  if (err)
+    return uv_translate_sys_error(err);
+
+  return 0;
+}
+
+
+int uv_socketpair(int type, int protocol, uv_os_sock_t fds[2], int flags0, int flags1) {
+  SOCKET server = INVALID_SOCKET;
+  SOCKET client0 = INVALID_SOCKET;
+  SOCKET client1 = INVALID_SOCKET;
+  SOCKADDR_IN name;
+  LPFN_ACCEPTEX func_acceptex;
+  WSAOVERLAPPED overlap;
+  char accept_buffer[sizeof(struct sockaddr_storage) * 2 + 32];
+  int namelen;
+  int err;
+  DWORD bytes;
+  DWORD flags;
+  DWORD client0_flags = WSA_FLAG_NO_HANDLE_INHERIT;
+  DWORD client1_flags = WSA_FLAG_NO_HANDLE_INHERIT;
+
+  if (flags0 & UV_NONBLOCK_PIPE)
+      client0_flags |= WSA_FLAG_OVERLAPPED;
+  if (flags1 & UV_NONBLOCK_PIPE)
+      client1_flags |= WSA_FLAG_OVERLAPPED;
+
+  server = WSASocketW(AF_INET, type, protocol, NULL, 0,
+                      WSA_FLAG_OVERLAPPED | WSA_FLAG_NO_HANDLE_INHERIT);
+  if (server == INVALID_SOCKET)
+    goto wsaerror;
+  if (!SetHandleInformation((HANDLE) server, HANDLE_FLAG_INHERIT, 0))
+    goto error;
+  name.sin_family = AF_INET;
+  name.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+  name.sin_port = 0;
+  if (bind(server, (SOCKADDR*) &name, sizeof(name)) != 0)
+    goto wsaerror;
+  if (listen(server, 1) != 0)
+    goto wsaerror;
+  namelen = sizeof(name);
+  if (getsockname(server, (SOCKADDR*) &name, &namelen) != 0)
+    goto wsaerror;
+  client0 = WSASocketW(AF_INET, type, protocol, NULL, 0, client0_flags);
+  if (client0 == INVALID_SOCKET)
+    goto wsaerror;
+  if (!SetHandleInformation((HANDLE) client0, HANDLE_FLAG_INHERIT, 0))
+    goto error;
+  if (connect(client0, (SOCKADDR*) &name, sizeof(name)) != 0)
+    goto wsaerror;
+  client1 = WSASocketW(AF_INET, type, protocol, NULL, 0, client1_flags);
+  if (client1 == INVALID_SOCKET)
+    goto wsaerror;
+  if (!SetHandleInformation((HANDLE) client1, HANDLE_FLAG_INHERIT, 0))
+    goto error;
+  if (!uv__get_acceptex_function(server, &func_acceptex)) {
+    err = WSAEAFNOSUPPORT;
+    goto cleanup;
+  }
+  memset(&overlap, 0, sizeof(overlap));
+  if (!func_acceptex(server,
+                     client1,
+                     accept_buffer,
+                     0,
+                     sizeof(struct sockaddr_storage),
+                     sizeof(struct sockaddr_storage),
+                     &bytes,
+                     &overlap)) {
+    err = WSAGetLastError();
+    if (err == ERROR_IO_PENDING) {
+      /* Result should complete immediately, since we already called connect,
+       * but empirically, we sometimes have to poll the kernel a couple times
+       * until it notices that. */
+      while (!WSAGetOverlappedResult(client1, &overlap, &bytes, FALSE, &flags)) {
+        err = WSAGetLastError();
+        if (err != WSA_IO_INCOMPLETE)
+          goto cleanup;
+        SwitchToThread();
+      }
+    }
+    else {
+      goto cleanup;
+    }
+  }
+  if (setsockopt(client1, SOL_SOCKET, SO_UPDATE_ACCEPT_CONTEXT,
+                  (char*) &server, sizeof(server)) != 0) {
+    goto wsaerror;
+  }
+
+  closesocket(server);
+
+  fds[0] = client0;
+  fds[1] = client1;
+
+  return 0;
+
+ wsaerror:
+    err = WSAGetLastError();
+    goto cleanup;
+
+ error:
+    err = GetLastError();
+    goto cleanup;
+
+ cleanup:
+    if (server != INVALID_SOCKET)
+      closesocket(server);
+    if (client0 != INVALID_SOCKET)
+      closesocket(client0);
+    if (client1 != INVALID_SOCKET)
+      closesocket(client1);
+
+    assert(err);
+    return uv_translate_sys_error(err);
+}