First draft of the win32 implementation of iomgr.

Caveats:
-) The win32 pollset isn't threadsafe (yet).
-) Only client code is implemented.
-) Only very simple code has been tested with it yet.

12 files changed, 1133 insertions, 7 deletions

diff --git a/src/core/iomgr/iomgr_posix.c b/src/core/iomgr/iomgr_posix.c
index 9297f08e99..22ca74314c 100644
--- a/src/core/iomgr/iomgr_posix.c
+++ b/src/core/iomgr/iomgr_posix.c
@@ -31,6 +31,10 @@
  *
  */
 
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_POSIX_SOCKET
+
 #include "src/core/iomgr/iomgr_posix.h"
 #include "src/core/iomgr/fd_posix.h"
 
@@ -43,3 +47,5 @@ void grpc_iomgr_platform_shutdown(void) {
   grpc_pollset_global_shutdown();
   grpc_fd_global_shutdown();
 }
+
+#endif  /* GRPC_IOMGRP_POSIX */
diff --git a/src/core/iomgr/iomgr_windows.c b/src/core/iomgr/iomgr_windows.c
new file mode 100644
index 0000000000..9cdf224ad7
--- /dev/null
+++ b/src/core/iomgr/iomgr_windows.c
@@ -0,0 +1,67 @@
+/*
+ *
+ * Copyright 2014, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_WINSOCK_SOCKET
+
+#include "src/core/iomgr/sockaddr_win32.h"
+
+#include <grpc/support/log.h>
+
+#include "src/core/iomgr/socket_windows.h"
+#include "src/core/iomgr/iomgr.h"
+#include "src/core/iomgr/iomgr_windows.h"
+
+static void winsock_init(void) {
+  WSADATA wsaData;
+  int status = WSAStartup(MAKEWORD(2, 0), &wsaData);
+  GPR_ASSERT(status == 0);
+}
+
+static void winsock_shutdown(void) {
+  int status = WSACleanup();
+  GPR_ASSERT(status == 0);
+}
+
+void grpc_iomgr_platform_init(void) {
+  winsock_init();
+  grpc_pollset_global_init();
+}
+
+void grpc_iomgr_platform_shutdown(void) {
+  grpc_pollset_global_shutdown();
+  winsock_shutdown();
+}
+
+#endif  /* GRPC_IOMGRP_POSIX */
diff --git a/src/core/iomgr/iomgr_windows.h b/src/core/iomgr/iomgr_windows.h
new file mode 100644
index 0000000000..2d9449c1f6
--- /dev/null
+++ b/src/core/iomgr/iomgr_windows.h
@@ -0,0 +1,42 @@
+/*
+ *
+ * Copyright 2014, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef __GRPC_INTERNAL_IOMGR_IOMGR_WINDOWS_H_
+#define __GRPC_INTERNAL_IOMGR_IOMGR_WINDOWS_H_
+
+#include "src/core/iomgr/socket_windows.h"
+
+void grpc_pollset_global_init(void);
+void grpc_pollset_global_shutdown(void);
+
+#endif /* __GRPC_INTERNAL_IOMGR_IOMGR_WINDOWS_H_ */
diff --git a/src/core/iomgr/pollset_windows.c b/src/core/iomgr/pollset_windows.c
index 3fb39918b3..fdebede482 100644
--- a/src/core/iomgr/pollset_windows.c
+++ b/src/core/iomgr/pollset_windows.c
@@ -33,6 +33,187 @@
 
 #include <grpc/support/port_platform.h>
 
-#ifdef GPR_WIN32
+#ifdef GPR_WINSOCK_SOCKET
 
-#endif /* GPR_WIN32 */
+#include <winsock2.h>
+
+#include <grpc/support/log.h>
+#include <grpc/support/thd.h>
+
+#include "src/core/iomgr/alarm_internal.h"
+#include "src/core/iomgr/socket_windows.h"
+#include "src/core/iomgr/iomgr_internal.h"
+#include "src/core/iomgr/pollset_windows.h"
+
+static grpc_pollset g_global_pollset;
+static ULONG g_pollset_kick_token;
+static OVERLAPPED g_pollset_custom_overlap;
+
+static gpr_event g_shutdown_global_poller;
+static gpr_event g_global_poller_done;
+
+void grpc_pollset_init(grpc_pollset *pollset) {
+  pollset->iocp = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL,
+                                         (ULONG_PTR)NULL, 0);
+  GPR_ASSERT(pollset->iocp);
+}
+
+void grpc_pollset_destroy(grpc_pollset *pollset) {
+  BOOL status;
+  status = CloseHandle(pollset->iocp);
+  GPR_ASSERT(status);
+}
+
+static int pollset_poll(grpc_pollset *pollset,
+                        gpr_timespec deadline, gpr_timespec now) {
+  BOOL success;
+  DWORD bytes = 0;
+  DWORD flags = 0;
+  ULONG_PTR completion_key;
+  LPOVERLAPPED overlapped;
+  gpr_timespec wait_time = gpr_time_sub(deadline, now);
+  grpc_winsocket *socket;
+  grpc_winsocket_callback_info *info;
+  void(*f)(void *, int) = NULL;
+  void *opaque = NULL;
+  success = GetQueuedCompletionStatus(pollset->iocp, &bytes,
+                                     &completion_key, &overlapped,
+                                     gpr_time_to_millis(wait_time));
+
+  if (!success && !overlapped) {
+    /* The deadline got attained. */
+    return 0;
+  }
+  GPR_ASSERT(completion_key && overlapped);
+  if (overlapped == &g_pollset_custom_overlap) {
+    if (completion_key == (ULONG_PTR) &g_pollset_kick_token) {
+      /* We were awoken from a kick. */
+      gpr_log(GPR_DEBUG, "pollset_poll - got a kick");
+      return 1;
+    }
+    gpr_log(GPR_ERROR, "Unknown custom completion key.");
+    abort();
+  }
+
+  socket = (grpc_winsocket*) completion_key;
+  if (overlapped == &socket->write_info.overlapped) {
+    gpr_log(GPR_DEBUG, "pollset_poll - got write packet");
+    info = &socket->write_info;
+  } else if (overlapped == &socket->read_info.overlapped) {
+    gpr_log(GPR_DEBUG, "pollset_poll - got read packet");
+    info = &socket->read_info;
+  } else {
+    gpr_log(GPR_ERROR, "Unknown IOCP operation");
+    abort();
+  }
+  success = WSAGetOverlappedResult(socket->socket, &info->overlapped, &bytes,
+                                   FALSE, &flags);
+  gpr_log(GPR_DEBUG, "bytes: %u, flags: %u - op %s", bytes, flags,
+          success ? "succeeded" : "failed");
+  info->bytes_transfered = bytes;
+  info->wsa_error = success ? 0 : WSAGetLastError();
+  GPR_ASSERT(overlapped == &info->overlapped);
+  gpr_mu_lock(&socket->state_mu);
+  GPR_ASSERT(!info->has_pending_iocp);
+  if (info->cb) {
+    f = info->cb;
+    opaque = info->opaque;
+    info->cb = NULL;
+  } else {
+    info->has_pending_iocp = 1;
+  }
+  gpr_mu_unlock(&socket->state_mu);
+  if (f) f(opaque, 1);
+
+  return 1;
+}
+
+int grpc_pollset_work(grpc_pollset *pollset, gpr_timespec deadline) {
+  gpr_timespec now;
+  now = gpr_now();
+  if (gpr_time_cmp(now, deadline) > 0) {
+    return 0;
+  }
+  if (grpc_maybe_call_delayed_callbacks(NULL, 1)) {
+    return 1;
+  }
+  if (grpc_alarm_check(NULL, now, &deadline)) {
+    return 1;
+  }
+  return pollset_poll(pollset, deadline, now);
+}
+
+void grpc_pollset_kick(grpc_pollset *pollset) {
+  BOOL status;
+  status = PostQueuedCompletionStatus(pollset->iocp, 0,
+                                      (ULONG_PTR) &g_pollset_kick_token,
+                                      &g_pollset_custom_overlap);
+  GPR_ASSERT(status);
+}
+
+static void global_poller(void *p) {
+  while (!gpr_event_get(&g_shutdown_global_poller)) {
+    grpc_pollset_work(&g_global_pollset, gpr_inf_future);
+  }
+
+  gpr_event_set(&g_global_poller_done, (void *) 1);
+}
+
+void grpc_pollset_global_init(void) {
+  gpr_thd_id id;
+
+  grpc_pollset_init(&g_global_pollset);
+  gpr_event_init(&g_global_poller_done);
+  gpr_event_init(&g_shutdown_global_poller);
+  gpr_thd_new(&id, global_poller, NULL, NULL);
+}
+
+void grpc_pollset_global_shutdown(void) {
+  gpr_event_set(&g_shutdown_global_poller, (void *) 1);
+  grpc_pollset_kick(&g_global_pollset);
+  gpr_event_wait(&g_global_poller_done, gpr_inf_future);
+  grpc_pollset_destroy(&g_global_pollset);
+}
+
+void grpc_pollset_add_handle(grpc_pollset *pollset, grpc_winsocket *socket) {
+  HANDLE ret = CreateIoCompletionPort((HANDLE) socket->socket, pollset->iocp,
+                                      (gpr_uintptr) socket, 0);
+  GPR_ASSERT(ret == pollset->iocp);
+}
+
+static void handle_notify_on_iocp(grpc_winsocket *socket,
+                                  void(*cb)(void *, int), void *opaque,
+                                  grpc_winsocket_callback_info *info) {
+  int run_now = 0;
+  GPR_ASSERT(!info->cb);
+  gpr_mu_lock(&socket->state_mu);
+  if (info->has_pending_iocp) {
+    run_now = 1;
+    info->has_pending_iocp = 0;
+    gpr_log(GPR_DEBUG, "handle_notify_on_iocp - runs now");
+  } else {
+    info->cb = cb;
+    info->opaque = opaque;
+    gpr_log(GPR_DEBUG, "handle_notify_on_iocp - queued");
+  }
+  gpr_mu_unlock(&socket->state_mu);
+  if (run_now) cb(opaque, 1);
+}
+
+void grpc_handle_notify_on_write(grpc_winsocket *socket,
+                                 void(*cb)(void *, int), void *opaque) {
+  gpr_log(GPR_DEBUG, "grpc_handle_notify_on_write");
+  handle_notify_on_iocp(socket, cb, opaque, &socket->write_info);
+}
+
+void grpc_handle_notify_on_read(grpc_winsocket *socket,
+                                void(*cb)(void *, int), void *opaque) {
+  gpr_log(GPR_DEBUG, "grpc_handle_notify_on_read");
+  handle_notify_on_iocp(socket, cb, opaque, &socket->read_info);
+}
+
+grpc_pollset *grpc_global_pollset(void) {
+  return &g_global_pollset;
+}
+
+#endif  /* GPR_WINSOCK_SOCKET */
diff --git a/src/core/iomgr/pollset_windows.h b/src/core/iomgr/pollset_windows.h
index 9214b04b17..036f3910a0 100644
--- a/src/core/iomgr/pollset_windows.h
+++ b/src/core/iomgr/pollset_windows.h
@@ -34,9 +34,11 @@
 #ifndef __GRPC_INTERNAL_IOMGR_POLLSET_WINDOWS_H_
 #define __GRPC_INTERNAL_IOMGR_POLLSET_WINDOWS_H_
 
+#include <windows.h>
 #include <grpc/support/sync.h>
 
 #include "src/core/iomgr/pollset_kick.h"
+#include "src/core/iomgr/socket_windows.h"
 
 /* forward declare only in this file to avoid leaking impl details via
    pollset.h; real users of grpc_fd should always include 'fd_posix.h' and not
@@ -44,11 +46,20 @@
 struct grpc_fd;
 
 typedef struct grpc_pollset {
-  gpr_mu mu;
-  gpr_cv cv;
+  HANDLE iocp;
 } grpc_pollset;
 
-#define GRPC_POLLSET_MU(pollset) (&(pollset)->mu)
-#define GRPC_POLLSET_CV(pollset) (&(pollset)->cv)
+#define GRPC_POLLSET_MU(pollset) (NULL)
+#define GRPC_POLLSET_CV(pollset) (NULL)
+
+void grpc_pollset_add_handle(grpc_pollset *, grpc_winsocket *);
+
+grpc_pollset *grpc_global_pollset(void);
+
+void grpc_handle_notify_on_write(grpc_winsocket *, void(*cb)(void *, int success),
+                                 void *opaque);
+
+void grpc_handle_notify_on_read(grpc_winsocket *, void(*cb)(void *, int success),
+                                void *opaque);
 
 #endif /* __GRPC_INTERNAL_IOMGR_POLLSET_WINDOWS_H_ */
diff --git a/src/core/iomgr/sockaddr_win32.h b/src/core/iomgr/sockaddr_win32.h
index cdea33fec0..350f5fa33e 100644
--- a/src/core/iomgr/sockaddr_win32.h
+++ b/src/core/iomgr/sockaddr_win32.h
@@ -35,5 +35,7 @@
 #define __GRPC_INTERNAL_IOMGR_SOCKADDR_WIN32_H_
 
 #include <ws2tcpip.h>
+#include <winsock2.h>
+#include <mswsock.h>
 
 #endif  // __GRPC_INTERNAL_IOMGR_SOCKADDR_WIN32_H_
diff --git a/src/core/iomgr/socket_windows.c b/src/core/iomgr/socket_windows.c
new file mode 100644
index 0000000000..7d1d59c318
--- /dev/null
+++ b/src/core/iomgr/socket_windows.c
@@ -0,0 +1,76 @@
+/*
+ *
+ * Copyright 2014, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
+#ifdef GPR_WINSOCK_SOCKET
+
+#include "src/core/iomgr/iomgr.h"
+#include "src/core/iomgr/iomgr_internal.h"
+#include "src/core/iomgr/socket_windows.h"
+#include "src/core/iomgr/pollset.h"
+#include "src/core/iomgr/pollset_windows.h"
+
+grpc_winsocket *grpc_winsocket_create(SOCKET socket) {
+  grpc_winsocket *r = gpr_malloc(sizeof(grpc_winsocket));
+  gpr_log(GPR_DEBUG, "grpc_winsocket_create");
+  memset(r, 0, sizeof(grpc_winsocket));
+  r->socket = socket;
+  gpr_mu_init(&r->state_mu);
+  grpc_iomgr_ref();
+  grpc_pollset_add_handle(grpc_global_pollset(), r);
+  return r;
+}
+
+void shutdown_op(grpc_winsocket_callback_info *info) {
+  if (!info->cb) return;
+  info->cb(info->opaque, 0);
+}
+
+void grpc_winsocket_shutdown(grpc_winsocket *socket) {
+  gpr_log(GPR_DEBUG, "grpc_winsocket_shutdown");
+  shutdown_op(&socket->read_info);
+  shutdown_op(&socket->write_info);
+}
+
+void grpc_winsocket_orphan(grpc_winsocket *socket) {
+  gpr_log(GPR_DEBUG, "grpc_winsocket_orphan");
+  grpc_iomgr_unref();
+  closesocket(socket->socket);
+  gpr_mu_destroy(&socket->state_mu);
+  gpr_free(socket);
+}
+
+#endif
diff --git a/src/core/iomgr/socket_windows.h b/src/core/iomgr/socket_windows.h
new file mode 100644
index 0000000000..ca85ea54cb
--- /dev/null
+++ b/src/core/iomgr/socket_windows.h
@@ -0,0 +1,73 @@
+/*
+ *
+ * Copyright 2014, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef __GRPC_INTERNAL_IOMGR_HANDLE_WINDOWS_H__
+#define __GRPC_INTERNAL_IOMGR_HANDLE_WINDOWS_H__
+
+#include <windows.h>
+
+#include <grpc/support/sync.h>
+#include <grpc/support/atm.h>
+
+typedef struct grpc_winsocket_callback_info {
+  /* I hate Microsoft so much. This is supposed to be a WSAOVERLAPPED,
+   * but in order to get that definition, we need to include ws2tcpip.h,
+   * which needs to be included from the top, otherwise it'll clash with
+   * a previous inclusion of windows.h that in turns includes winsock.h.
+   * If anyone knows a way to do it properly, feel free to send a patch.
+   */
+  OVERLAPPED overlapped;
+  void(*cb)(void *opaque, int success);
+  void *opaque;
+  int has_pending_iocp;
+  DWORD bytes_transfered;
+  int wsa_error;
+} grpc_winsocket_callback_info;
+
+typedef struct grpc_winsocket {
+  SOCKET socket;
+
+  grpc_winsocket_callback_info write_info;
+  grpc_winsocket_callback_info read_info;
+
+  gpr_mu state_mu;
+} grpc_winsocket;
+
+/* Create a wrapped windows handle.
+This takes ownership of closing it. */
+grpc_winsocket *grpc_winsocket_create(SOCKET socket);
+
+void grpc_winsocket_shutdown(grpc_winsocket *socket);
+void grpc_winsocket_orphan(grpc_winsocket *socket);
+
+#endif /* __GRPC_INTERNAL_IOMGR_FD_POSIX_H_ */
diff --git a/src/core/iomgr/tcp_client_windows.c b/src/core/iomgr/tcp_client_windows.c
new file mode 100644
index 0000000000..465fc75295
--- /dev/null
+++ b/src/core/iomgr/tcp_client_windows.c
@@ -0,0 +1,219 @@
+/*
+ *
+ * Copyright 2014, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_WINSOCK_SOCKET
+
+#include "src/core/iomgr/sockaddr_win32.h"
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/log_win32.h>
+#include <grpc/support/slice_buffer.h>
+#include <grpc/support/useful.h>
+
+#include "src/core/iomgr/tcp_client.h"
+#include "src/core/iomgr/tcp_windows.h"
+#include "src/core/iomgr/socket_windows.h"
+#include "src/core/iomgr/alarm.h"
+#include "src/core/iomgr/sockaddr.h"
+#include "src/core/iomgr/sockaddr_utils.h"
+
+typedef struct {
+  void(*cb)(void *arg, grpc_endpoint *tcp);
+  void *cb_arg;
+  gpr_mu mu;
+  grpc_winsocket *socket;
+  gpr_timespec deadline;
+  grpc_alarm alarm;
+  int refs;
+} async_connect;
+
+static void async_connect_cleanup(async_connect *ac) {
+  int done = (--ac->refs == 0);
+  gpr_mu_unlock(&ac->mu);
+  if (done) {
+    gpr_mu_destroy(&ac->mu);
+    gpr_free(ac);
+  }
+}
+
+static void on_alarm(void *acp, int success) {
+  async_connect *ac = acp;
+  gpr_mu_lock(&ac->mu);
+  if (ac->socket != NULL && success) {
+    grpc_winsocket_shutdown(ac->socket);
+  }
+  async_connect_cleanup(ac);
+}
+
+static void on_connect(void *acp, int success) {
+  async_connect *ac = acp;
+  SOCKET sock = ac->socket->socket;
+  grpc_endpoint *ep = NULL;
+  grpc_winsocket_callback_info *info = &ac->socket->write_info;
+  void(*cb)(void *arg, grpc_endpoint *tcp) = ac->cb;
+  void *cb_arg = ac->cb_arg;
+
+  grpc_alarm_cancel(&ac->alarm);
+
+  if (success) {
+    DWORD transfered_bytes = 0;
+    DWORD flags;
+    BOOL wsa_success = WSAGetOverlappedResult(sock, &info->overlapped,
+                                              &transfered_bytes, FALSE,
+                                              &flags);
+    GPR_ASSERT(transfered_bytes == 0);
+    if (!wsa_success) {
+      char *utf8_message = gpr_format_message(WSAGetLastError());
+      gpr_log(GPR_ERROR, "on_connect error: %s", utf8_message);
+      gpr_free(utf8_message);
+      goto finish;
+    } else {
+      gpr_log(GPR_DEBUG, "on_connect: connection established");
+      ep = grpc_tcp_create(ac->socket);
+      goto finish;
+    }
+  } else {
+    __debugbreak();
+    abort();
+    gpr_log(GPR_ERROR, "on_writable failed during connect");
+    goto finish;
+  }
+
+  abort();
+
+finish:
+  gpr_mu_lock(&ac->mu);
+  if (!ep) {
+    grpc_winsocket_orphan(ac->socket);
+  }
+  async_connect_cleanup(ac);
+  cb(cb_arg, ep);
+}
+
+void grpc_tcp_client_connect(void(*cb)(void *arg, grpc_endpoint *tcp),
+                             void *arg, const struct sockaddr *addr,
+                             int addr_len, gpr_timespec deadline) {
+  SOCKET sock = INVALID_SOCKET;
+  BOOL success;
+  int status;
+  struct sockaddr_in6 addr6_v4mapped;
+  struct sockaddr_in6 local_address;
+  async_connect *ac;
+  grpc_winsocket *socket = NULL;
+  LPFN_CONNECTEX ConnectEx;
+  GUID guid = WSAID_CONNECTEX;
+  DWORD ioctl_num_bytes;
+  const char *message = NULL;
+  char *utf8_message;
+  grpc_winsocket_callback_info *info;
+
+  /* Use dualstack sockets where available. */
+  if (grpc_sockaddr_to_v4mapped(addr, &addr6_v4mapped)) {
+    addr = (const struct sockaddr *)&addr6_v4mapped;
+    addr_len = sizeof(addr6_v4mapped);
+  }
+
+  sock = WSASocket(AF_INET6, SOCK_STREAM, IPPROTO_TCP, NULL, 0,
+                   WSA_FLAG_OVERLAPPED);
+  if (sock == INVALID_SOCKET) {
+    message = "Unable to create socket: %s";
+    goto failure;
+  }
+
+  if (!grpc_tcp_prepare_socket(sock)) {
+    message = "Unable to set socket options: %s";
+    goto failure;
+  }
+
+  status = WSAIoctl(sock, SIO_GET_EXTENSION_FUNCTION_POINTER,
+                    &guid, sizeof(guid), &ConnectEx, sizeof(ConnectEx),
+                    &ioctl_num_bytes, NULL, NULL);
+
+  if (status != 0) {
+    message = "Unable to retreive ConnectEx pointer: %s";
+    goto failure;
+  }
+
+  memset(&local_address, 0, sizeof(local_address));
+  memcpy(&local_address.sin6_addr, &in6addr_any, sizeof(in6addr_any));
+  local_address.sin6_family = AF_INET6;
+
+  status = bind(sock, (struct sockaddr *) &local_address,
+                sizeof(local_address));
+  if (status != 0) {
+    message = "Unable to bind socket: %s";
+    goto failure;
+  }
+
+  socket = grpc_winsocket_create(sock);
+  info = &socket->write_info;
+  success = ConnectEx(sock, addr, addr_len, NULL, 0, NULL, &info->overlapped);
+
+  if (success) {
+    gpr_log(GPR_DEBUG, "connected immediately - but we still go to sleep");
+  } else {
+    int error = WSAGetLastError();
+    if (error != ERROR_IO_PENDING) {
+      message = "ConnectEx failed: %s";
+      goto failure;
+    }
+  }
+
+  gpr_log(GPR_DEBUG, "grpc_tcp_client_connect: connection pending");
+  ac = gpr_malloc(sizeof(async_connect));
+  ac->cb = cb;
+  ac->cb_arg = arg;
+  ac->socket = socket;
+  gpr_mu_init(&ac->mu);
+  ac->refs = 2;
+
+  grpc_alarm_init(&ac->alarm, deadline, on_alarm, ac, gpr_now());
+  grpc_handle_notify_on_write(socket, on_connect, ac);
+  return;
+
+failure:
+  utf8_message = gpr_format_message(WSAGetLastError());
+  gpr_log(GPR_ERROR, message, utf8_message);
+  gpr_free(utf8_message);
+  if (socket) {
+    grpc_winsocket_orphan(socket);
+  } else if (sock != INVALID_SOCKET) {
+    closesocket(sock);
+  }
+  cb(arg, NULL);
+}
+
+#endif  /* GPR_WINSOCK_SOCKET */
diff --git a/src/core/iomgr/tcp_windows.c b/src/core/iomgr/tcp_windows.c
new file mode 100644
index 0000000000..0eb6663dd4
--- /dev/null
+++ b/src/core/iomgr/tcp_windows.c
@@ -0,0 +1,357 @@
+/*
+ *
+ * Copyright 2014, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_WINSOCK_SOCKET
+
+#include "src/core/iomgr/sockaddr_win32.h"
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/log_win32.h>
+#include <grpc/support/slice_buffer.h>
+#include <grpc/support/useful.h>
+
+#include "src/core/iomgr/tcp_client.h"
+#include "src/core/iomgr/socket_windows.h"
+#include "src/core/iomgr/alarm.h"
+#include "src/core/iomgr/sockaddr.h"
+#include "src/core/iomgr/sockaddr_utils.h"
+
+static int set_non_block(SOCKET sock) {
+  int status;
+  unsigned long param = 1;
+  DWORD ret;
+  status = WSAIoctl(sock, FIONBIO, &param, sizeof(param), NULL, 0, &ret,
+                    NULL, NULL);
+  return status == 0;
+}
+
+int grpc_tcp_prepare_socket(SOCKET sock) {
+  if (!set_non_block(sock))
+    return 0;
+  return 1;
+}
+
+typedef struct grpc_tcp {
+  grpc_endpoint base;
+  grpc_winsocket *socket;
+  gpr_refcount refcount;
+
+  grpc_endpoint_read_cb read_cb;
+  void *read_user_data;
+  gpr_slice read_slice;
+  int outstanding_read;
+
+  grpc_endpoint_write_cb write_cb;
+  void *write_user_data;
+  gpr_slice_buffer write_slices;
+  int outstanding_write;
+
+} grpc_tcp;
+
+static void tcp_ref(grpc_tcp *tcp) {
+  gpr_log(GPR_DEBUG, "tcp_ref");
+  gpr_ref(&tcp->refcount);
+}
+
+static void tcp_unref(grpc_tcp *tcp) {
+  gpr_log(GPR_DEBUG, "tcp_unref");
+  if (gpr_unref(&tcp->refcount)) {
+    gpr_log(GPR_DEBUG, "tcp_unref: destroying");
+    gpr_slice_buffer_destroy(&tcp->write_slices);
+    grpc_winsocket_orphan(tcp->socket);
+    gpr_free(tcp);
+  }
+}
+
+static void on_read(void *tcpp, int success) {
+  grpc_tcp *tcp = (grpc_tcp *) tcpp;
+  grpc_winsocket *socket = tcp->socket;
+  gpr_slice sub;
+  gpr_slice *slice = NULL;
+  size_t nslices = 0;
+  grpc_endpoint_cb_status status;
+  grpc_endpoint_read_cb cb = tcp->read_cb;
+  grpc_winsocket_callback_info *info = &socket->read_info;
+  void *opaque = tcp->read_user_data;
+
+  GPR_ASSERT(tcp->outstanding_read);
+
+  if (!success) {
+    __debugbreak();
+    abort();
+  }
+
+  gpr_log(GPR_DEBUG, "on_read");
+  tcp->outstanding_read = 0;
+
+  if (socket->read_info.wsa_error != 0) {
+    char *utf8_message = gpr_format_message(info->wsa_error);
+    __debugbreak();
+    gpr_log(GPR_ERROR, "ReadFile overlapped error: %s", utf8_message);
+    gpr_free(utf8_message);
+    status = GRPC_ENDPOINT_CB_ERROR;
+  } else {
+    if (info->bytes_transfered != 0) {
+      sub = gpr_slice_sub(tcp->read_slice, 0, info->bytes_transfered);
+      gpr_log(GPR_DEBUG, "on_read: calling callback");
+      status = GRPC_ENDPOINT_CB_OK;
+      slice = &sub;
+      nslices = 1;
+    } else {
+      gpr_log(GPR_DEBUG, "on_read: closed socket");
+      gpr_slice_unref(tcp->read_slice);
+      status = GRPC_ENDPOINT_CB_EOF;
+    }
+  }
+  tcp_unref(tcp);
+  cb(opaque, slice, nslices, status);
+}
+
+static void win_notify_on_read(grpc_endpoint *ep,
+                               grpc_endpoint_read_cb cb, void *arg) {
+  grpc_tcp *tcp = (grpc_tcp *) ep;
+  grpc_winsocket *handle = tcp->socket;
+  grpc_winsocket_callback_info *info = &handle->read_info;
+  int status;
+  DWORD bytes_read = 0;
+  DWORD flags = 0;
+  int error;
+  WSABUF buffer;
+
+  GPR_ASSERT(!tcp->outstanding_read);
+  tcp_ref(tcp);
+  tcp->outstanding_read = 1;
+  tcp->read_cb = cb;
+  tcp->read_user_data = arg;
+
+  tcp->read_slice = gpr_slice_malloc(8192);
+
+  buffer.len = GPR_SLICE_LENGTH(tcp->read_slice);
+  buffer.buf = GPR_SLICE_START_PTR(tcp->read_slice);
+
+  gpr_log(GPR_DEBUG, "win_notify_on_read: calling WSARecv without overlap");
+
+  status = WSARecv(tcp->socket->socket, &buffer, 1, &bytes_read, &flags,
+                   NULL, NULL);
+  info->wsa_error = status == 0 ? 0 : WSAGetLastError();
+
+  if (info->wsa_error != WSAEWOULDBLOCK) {
+    gpr_log(GPR_DEBUG, "got response immediately, calling on_read");
+    info->bytes_transfered = bytes_read;
+    /* This might heavily recurse. */
+    on_read(tcp, 1);
+    return;
+  }
+
+  gpr_log(GPR_DEBUG, "got WSAEWOULDBLOCK - calling WSARecv with overlap");
+
+  memset(&tcp->socket->read_info.overlapped, 0, sizeof(OVERLAPPED));
+  status = WSARecv(tcp->socket->socket, &buffer, 1, &bytes_read, &flags,
+                   &info->overlapped, NULL);
+
+  if (status == 0) {
+    gpr_log(GPR_DEBUG, "got response immediately, but we're goint to sleep");
+    grpc_handle_notify_on_read(tcp->socket, on_read, tcp);
+    return;
+  }
+
+  error = WSAGetLastError();
+
+  if (error != WSA_IO_PENDING) {
+    char *utf8_message = gpr_format_message(WSAGetLastError());
+    __debugbreak();
+    gpr_log(GPR_ERROR, "WSARecv error: %s", utf8_message);
+    gpr_free(utf8_message);
+    /* would the IO completion port be called anyway... ? Let's assume not. */
+    tcp->outstanding_read = 0;
+    tcp_unref(tcp);
+    cb(arg, NULL, 0, GRPC_ENDPOINT_CB_ERROR);
+    return;
+  }
+
+  gpr_log(GPR_DEBUG, "waiting on the IO completion port now");
+  grpc_handle_notify_on_read(tcp->socket, on_read, tcp);
+}
+
+static void on_write(void *tcpp, int success) {
+  grpc_tcp *tcp = (grpc_tcp *) tcpp;
+  grpc_winsocket *handle = tcp->socket;
+  grpc_winsocket_callback_info *info = &handle->write_info;
+  grpc_endpoint_cb_status status = GRPC_ENDPOINT_CB_OK;
+  grpc_endpoint_write_cb cb = tcp->write_cb;
+  void *opaque = tcp->write_user_data;
+
+  GPR_ASSERT(tcp->outstanding_write);
+
+  gpr_log(GPR_DEBUG, "on_write");
+
+  if (!success) {
+    __debugbreak();
+    abort();
+  }
+
+  if (info->wsa_error != 0) {
+    char *utf8_message = gpr_format_message(info->wsa_error);
+    gpr_log(GPR_ERROR, "WSASend overlapped error: %s", utf8_message);
+    gpr_free(utf8_message);
+    status = GRPC_ENDPOINT_CB_ERROR;
+  } else {
+    GPR_ASSERT(info->bytes_transfered == tcp->write_slices.length);
+  }
+
+  gpr_slice_buffer_reset_and_unref(&tcp->write_slices);
+  tcp->outstanding_write = 0;
+
+  tcp_unref(tcp);
+  cb(opaque, status);
+}
+
+static grpc_endpoint_write_status win_write(grpc_endpoint *ep,
+                                            gpr_slice *slices, size_t nslices,
+                                            grpc_endpoint_write_cb cb,
+                                            void *arg) {
+  grpc_tcp *tcp = (grpc_tcp *) ep;
+  grpc_winsocket *socket = tcp->socket;
+  grpc_winsocket_callback_info *info = &socket->write_info;
+  unsigned i;
+  DWORD bytes_sent;
+  int status;
+  WSABUF local_buffers[16];
+  WSABUF *allocated = NULL;
+  WSABUF *buffers = local_buffers;
+
+  GPR_ASSERT(nslices != 0);
+  GPR_ASSERT(GPR_SLICE_LENGTH(slices[0]) != 0);
+  GPR_ASSERT(!tcp->outstanding_write);
+  tcp_ref(tcp);
+
+  gpr_log(GPR_DEBUG, "win_write");
+
+  tcp->outstanding_write = 1;
+  tcp->write_cb = cb;
+  tcp->write_user_data = arg;
+  gpr_slice_buffer_addn(&tcp->write_slices, slices, nslices);
+
+  if (tcp->write_slices.count > GPR_ARRAY_SIZE(local_buffers)) {
+    buffers = (WSABUF *) gpr_malloc(sizeof(WSABUF) * tcp->write_slices.count);
+    allocated = buffers;
+  }
+
+  for (i = 0; i < tcp->write_slices.count; i++) {
+    buffers[i].len = GPR_SLICE_LENGTH(tcp->write_slices.slices[i]);
+    buffers[i].buf = GPR_SLICE_START_PTR(tcp->write_slices.slices[i]);
+  }
+
+  gpr_log(GPR_DEBUG, "win_write: calling WSASend without overlap");
+  status = WSASend(socket->socket, buffers, tcp->write_slices.count,
+                   &bytes_sent, 0, NULL, NULL);
+  info->wsa_error = status == 0 ? 0 : WSAGetLastError();
+
+  if (info->wsa_error != WSAEWOULDBLOCK) {
+    grpc_endpoint_write_status ret = GRPC_ENDPOINT_WRITE_ERROR;
+    gpr_log(GPR_DEBUG, "got response immediately, cleaning up and leaving");
+    if (status == 0) {
+      ret = GRPC_ENDPOINT_WRITE_DONE;
+      GPR_ASSERT(bytes_sent == tcp->write_slices.length);
+    }
+    if (allocated) gpr_free(allocated);
+    gpr_slice_buffer_reset_and_unref(&tcp->write_slices);
+    tcp->outstanding_write = 0;
+    tcp_unref(tcp);
+    return ret;
+  }
+
+  gpr_log(GPR_DEBUG, "got WSAEWOULDBLOCK - calling WSASend with overlap");
+
+  memset(&socket->write_info, 0, sizeof(OVERLAPPED));
+  status = WSASend(socket->socket, buffers, tcp->write_slices.count,
+                   &bytes_sent, 0, &socket->write_info.overlapped, NULL);
+  if (allocated) gpr_free(allocated);
+
+  if (status != 0) {
+    int error = WSAGetLastError();
+    if (error != WSA_IO_PENDING) {
+      char *utf8_message = gpr_format_message(WSAGetLastError());
+      __debugbreak();
+      gpr_log(GPR_ERROR, "WSASend error: %s", utf8_message);
+      gpr_free(utf8_message);
+      /* would the IO completion port be called anyway ? Let's assume not. */
+      tcp->outstanding_write = 0;
+      tcp_unref(tcp);
+      return GRPC_ENDPOINT_WRITE_ERROR;
+    }
+    gpr_log(GPR_DEBUG, "win_write: got pending op");
+  } else {
+    gpr_log(GPR_DEBUG, "wrote data immediately - but we're going to sleep");
+  }
+
+  grpc_handle_notify_on_write(socket, on_write, tcp);
+  return GRPC_ENDPOINT_WRITE_PENDING;
+}
+
+static void win_add_to_pollset(grpc_endpoint *ep, grpc_pollset *pollset) {
+  grpc_tcp *tcp = (grpc_tcp *) ep;
+  gpr_log(GPR_DEBUG, "win_add_to_pollset");
+  grpc_pollset_add_handle(pollset, tcp->socket);
+}
+
+static void win_shutdown(grpc_endpoint *ep) {
+  grpc_tcp *tcp = (grpc_tcp *) ep;
+  gpr_log(GPR_DEBUG, "win_shutdown");
+  grpc_winsocket_shutdown(tcp->socket);
+}
+
+static void win_destroy(grpc_endpoint *ep) {
+  grpc_tcp *tcp = (grpc_tcp *) ep;
+  gpr_log(GPR_DEBUG, "win_destroy");
+  tcp_unref(tcp);
+}
+
+static grpc_endpoint_vtable vtable = {
+  win_notify_on_read, win_write, win_add_to_pollset, win_shutdown, win_destroy
+};
+
+grpc_endpoint *grpc_tcp_create(grpc_winsocket *socket) {
+  grpc_tcp *tcp = (grpc_tcp *) gpr_malloc(sizeof(grpc_tcp));
+  memset(tcp, 0, sizeof(grpc_tcp));
+  tcp->base.vtable = &vtable;
+  tcp->socket = socket;
+  gpr_slice_buffer_init(&tcp->write_slices);
+  gpr_ref_init(&tcp->refcount, 1);
+  return &tcp->base;
+}
+
+#endif  /* GPR_WINSOCK_SOCKET */
diff --git a/src/core/iomgr/tcp_windows.h b/src/core/iomgr/tcp_windows.h
new file mode 100644
index 0000000000..cbe60801b4
--- /dev/null
+++ b/src/core/iomgr/tcp_windows.h
@@ -0,0 +1,57 @@
+/*
+ *
+ * Copyright 2014, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef __GRPC_INTERNAL_IOMGR_TCP_WINDOWS_H__
+#define __GRPC_INTERNAL_IOMGR_TCP_WINDOWS_H__
+/*
+   Low level TCP "bottom half" implementation, for use by transports built on
+   top of a TCP connection.
+
+   Note that this file does not (yet) include APIs for creating the socket in
+   the first place.
+
+   All calls passing slice transfer ownership of a slice refcount unless
+   otherwise specified.
+*/
+
+#include "src/core/iomgr/endpoint.h"
+#include "src/core/iomgr/socket_windows.h"
+
+/* Create a tcp endpoint given a winsock handle.
+ * Takes ownership of the handle.
+ */
+grpc_endpoint *grpc_tcp_create(grpc_winsocket *socket);
+
+int grpc_tcp_prepare_socket(SOCKET sock);
+
+#endif /* __GRPC_INTERNAL_IOMGR_TCP_WINDOWS_H__ */
diff --git a/src/core/support/log_win32.c b/src/core/support/log_win32.c
index dc8c1d0785..e1cf6fb10a 100644
--- a/src/core/support/log_win32.c
+++ b/src/core/support/log_win32.c
@@ -35,6 +35,7 @@
 
 #ifdef GPR_WIN32
 
+#include <grpc/support/log_win32.h>
 #include <grpc/support/log.h>
 #include <grpc/support/alloc.h>
 #include <stdio.h>
@@ -74,8 +75,42 @@ void gpr_log(const char *file, int line, gpr_log_severity severity,
 
 /* Simple starter implementation */
 void gpr_default_log(gpr_log_func_args *args) {
-  fprintf(stderr, "%s %s:%d: %s\n", gpr_log_severity_string(args->severity),
+  fprintf(stderr, "%s.%u %s:%d: %s\n",
+          gpr_log_severity_string(args->severity), GetCurrentThreadId(),
           args->file, args->line, args->message);
 }
 
+/* Arguable, this could become a public function. But hardly
+ * anything beside the Windows implementation should use
+ * it, so, never mind...*/
+#if defined UNICODE || defined _UNICODE
+static char *tchar_to_char(LPWSTR input) {
+  char *ret;
+  int needed = WideCharToMultiByte(CP_UTF8, 0, input, -1, NULL, 0, NULL, NULL);
+  if (needed == 0) return NULL;
+  ret = gpr_malloc(needed + 1);
+  WideCharToMultiByte(CP_UTF8, 0, input, -1, ret, needed, NULL, NULL);
+  ret[needed] = 0;
+  return ret;
+}
+#else
+static char *tchar_to_char(LPSTR input) {
+  return gpr_strdup(input);
+}
 #endif
+
+char *gpr_format_message(DWORD messageid) {
+  LPTSTR tmessage;
+  char *message;
+  DWORD status = FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER |
+                               FORMAT_MESSAGE_FROM_SYSTEM |
+                               FORMAT_MESSAGE_IGNORE_INSERTS,
+                               NULL, messageid,
+                               MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+                               (LPTSTR)(&tmessage), 0, NULL);
+  message = tchar_to_char(tmessage);
+  LocalFree(tmessage);
+  return message;
+}
+
+#endif  /* GPR_WIN32 */