diff options
Diffstat (limited to 'lib/asio/detail/impl/win_iocp_socket_service_base.ipp')
| -rw-r--r-- | lib/asio/detail/impl/win_iocp_socket_service_base.ipp | 799 |
1 files changed, 799 insertions, 0 deletions
diff --git a/lib/asio/detail/impl/win_iocp_socket_service_base.ipp b/lib/asio/detail/impl/win_iocp_socket_service_base.ipp new file mode 100644 index 0000000..6c478cd --- /dev/null +++ b/lib/asio/detail/impl/win_iocp_socket_service_base.ipp @@ -0,0 +1,799 @@ +// +// detail/impl/win_iocp_socket_service_base.ipp +// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +// +// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com) +// +// Distributed under the Boost Software License, Version 1.0. (See accompanying +// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) +// + +#ifndef ASIO_DETAIL_IMPL_WIN_IOCP_SOCKET_SERVICE_BASE_IPP +#define ASIO_DETAIL_IMPL_WIN_IOCP_SOCKET_SERVICE_BASE_IPP + +#if defined(_MSC_VER) && (_MSC_VER >= 1200) +# pragma once +#endif // defined(_MSC_VER) && (_MSC_VER >= 1200) + +#include "asio/detail/config.hpp" + +#if defined(ASIO_HAS_IOCP) + +#include "asio/detail/win_iocp_socket_service_base.hpp" + +#include "asio/detail/push_options.hpp" + +namespace asio { +namespace detail { + +win_iocp_socket_service_base::win_iocp_socket_service_base( + asio::io_context& io_context) + : io_context_(io_context), + iocp_service_(use_service<win_iocp_io_context>(io_context)), + reactor_(0), + connect_ex_(0), + nt_set_info_(0), + mutex_(), + impl_list_(0) +{ +} + +void win_iocp_socket_service_base::base_shutdown() +{ + // Close all implementations, causing all operations to complete. + asio::detail::mutex::scoped_lock lock(mutex_); + base_implementation_type* impl = impl_list_; + while (impl) + { + close_for_destruction(*impl); + impl = impl->next_; + } +} + +void win_iocp_socket_service_base::construct( + win_iocp_socket_service_base::base_implementation_type& impl) +{ + impl.socket_ = invalid_socket; + impl.state_ = 0; + impl.cancel_token_.reset(); +#if defined(ASIO_ENABLE_CANCELIO) + impl.safe_cancellation_thread_id_ = 0; +#endif // defined(ASIO_ENABLE_CANCELIO) + + // Insert implementation into linked list of all implementations. + asio::detail::mutex::scoped_lock lock(mutex_); + impl.next_ = impl_list_; + impl.prev_ = 0; + if (impl_list_) + impl_list_->prev_ = &impl; + impl_list_ = &impl; +} + +void win_iocp_socket_service_base::base_move_construct( + win_iocp_socket_service_base::base_implementation_type& impl, + win_iocp_socket_service_base::base_implementation_type& other_impl) +{ + impl.socket_ = other_impl.socket_; + other_impl.socket_ = invalid_socket; + + impl.state_ = other_impl.state_; + other_impl.state_ = 0; + + impl.cancel_token_ = other_impl.cancel_token_; + other_impl.cancel_token_.reset(); + +#if defined(ASIO_ENABLE_CANCELIO) + impl.safe_cancellation_thread_id_ = other_impl.safe_cancellation_thread_id_; + other_impl.safe_cancellation_thread_id_ = 0; +#endif // defined(ASIO_ENABLE_CANCELIO) + + // Insert implementation into linked list of all implementations. + asio::detail::mutex::scoped_lock lock(mutex_); + impl.next_ = impl_list_; + impl.prev_ = 0; + if (impl_list_) + impl_list_->prev_ = &impl; + impl_list_ = &impl; +} + +void win_iocp_socket_service_base::base_move_assign( + win_iocp_socket_service_base::base_implementation_type& impl, + win_iocp_socket_service_base& other_service, + win_iocp_socket_service_base::base_implementation_type& other_impl) +{ + close_for_destruction(impl); + + if (this != &other_service) + { + // Remove implementation from linked list of all implementations. + asio::detail::mutex::scoped_lock lock(mutex_); + if (impl_list_ == &impl) + impl_list_ = impl.next_; + if (impl.prev_) + impl.prev_->next_ = impl.next_; + if (impl.next_) + impl.next_->prev_= impl.prev_; + impl.next_ = 0; + impl.prev_ = 0; + } + + impl.socket_ = other_impl.socket_; + other_impl.socket_ = invalid_socket; + + impl.state_ = other_impl.state_; + other_impl.state_ = 0; + + impl.cancel_token_ = other_impl.cancel_token_; + other_impl.cancel_token_.reset(); + +#if defined(ASIO_ENABLE_CANCELIO) + impl.safe_cancellation_thread_id_ = other_impl.safe_cancellation_thread_id_; + other_impl.safe_cancellation_thread_id_ = 0; +#endif // defined(ASIO_ENABLE_CANCELIO) + + if (this != &other_service) + { + // Insert implementation into linked list of all implementations. + asio::detail::mutex::scoped_lock lock(other_service.mutex_); + impl.next_ = other_service.impl_list_; + impl.prev_ = 0; + if (other_service.impl_list_) + other_service.impl_list_->prev_ = &impl; + other_service.impl_list_ = &impl; + } +} + +void win_iocp_socket_service_base::destroy( + win_iocp_socket_service_base::base_implementation_type& impl) +{ + close_for_destruction(impl); + + // Remove implementation from linked list of all implementations. + asio::detail::mutex::scoped_lock lock(mutex_); + if (impl_list_ == &impl) + impl_list_ = impl.next_; + if (impl.prev_) + impl.prev_->next_ = impl.next_; + if (impl.next_) + impl.next_->prev_= impl.prev_; + impl.next_ = 0; + impl.prev_ = 0; +} + +asio::error_code win_iocp_socket_service_base::close( + win_iocp_socket_service_base::base_implementation_type& impl, + asio::error_code& ec) +{ + if (is_open(impl)) + { + ASIO_HANDLER_OPERATION((iocp_service_.context(), + "socket", &impl, impl.socket_, "close")); + + // Check if the reactor was created, in which case we need to close the + // socket on the reactor as well to cancel any operations that might be + // running there. + select_reactor* r = static_cast<select_reactor*>( + interlocked_compare_exchange_pointer( + reinterpret_cast<void**>(&reactor_), 0, 0)); + if (r) + r->deregister_descriptor(impl.socket_, impl.reactor_data_, true); + + socket_ops::close(impl.socket_, impl.state_, false, ec); + + if (r) + r->cleanup_descriptor_data(impl.reactor_data_); + } + else + { + ec = asio::error_code(); + } + + impl.socket_ = invalid_socket; + impl.state_ = 0; + impl.cancel_token_.reset(); +#if defined(ASIO_ENABLE_CANCELIO) + impl.safe_cancellation_thread_id_ = 0; +#endif // defined(ASIO_ENABLE_CANCELIO) + + return ec; +} + +socket_type win_iocp_socket_service_base::release( + win_iocp_socket_service_base::base_implementation_type& impl, + asio::error_code& ec) +{ + if (!is_open(impl)) + return invalid_socket; + + cancel(impl, ec); + if (ec) + return invalid_socket; + + nt_set_info_fn fn = get_nt_set_info(); + if (fn == 0) + { + ec = asio::error::operation_not_supported; + return invalid_socket; + } + + HANDLE sock_as_handle = reinterpret_cast<HANDLE>(impl.socket_); + ULONG_PTR iosb[2] = { 0, 0 }; + void* info[2] = { 0, 0 }; + if (fn(sock_as_handle, iosb, &info, sizeof(info), + 61 /* FileReplaceCompletionInformation */)) + { + ec = asio::error::operation_not_supported; + return invalid_socket; + } + + socket_type tmp = impl.socket_; + impl.socket_ = invalid_socket; + return tmp; +} + +asio::error_code win_iocp_socket_service_base::cancel( + win_iocp_socket_service_base::base_implementation_type& impl, + asio::error_code& ec) +{ + if (!is_open(impl)) + { + ec = asio::error::bad_descriptor; + return ec; + } + + ASIO_HANDLER_OPERATION((iocp_service_.context(), + "socket", &impl, impl.socket_, "cancel")); + + if (FARPROC cancel_io_ex_ptr = ::GetProcAddress( + ::GetModuleHandleA("KERNEL32"), "CancelIoEx")) + { + // The version of Windows supports cancellation from any thread. + typedef BOOL (WINAPI* cancel_io_ex_t)(HANDLE, LPOVERLAPPED); + cancel_io_ex_t cancel_io_ex = (cancel_io_ex_t)cancel_io_ex_ptr; + socket_type sock = impl.socket_; + HANDLE sock_as_handle = reinterpret_cast<HANDLE>(sock); + if (!cancel_io_ex(sock_as_handle, 0)) + { + DWORD last_error = ::GetLastError(); + if (last_error == ERROR_NOT_FOUND) + { + // ERROR_NOT_FOUND means that there were no operations to be + // cancelled. We swallow this error to match the behaviour on other + // platforms. + ec = asio::error_code(); + } + else + { + ec = asio::error_code(last_error, + asio::error::get_system_category()); + } + } + else + { + ec = asio::error_code(); + } + } +#if defined(ASIO_ENABLE_CANCELIO) + else if (impl.safe_cancellation_thread_id_ == 0) + { + // No operations have been started, so there's nothing to cancel. + ec = asio::error_code(); + } + else if (impl.safe_cancellation_thread_id_ == ::GetCurrentThreadId()) + { + // Asynchronous operations have been started from the current thread only, + // so it is safe to try to cancel them using CancelIo. + socket_type sock = impl.socket_; + HANDLE sock_as_handle = reinterpret_cast<HANDLE>(sock); + if (!::CancelIo(sock_as_handle)) + { + DWORD last_error = ::GetLastError(); + ec = asio::error_code(last_error, + asio::error::get_system_category()); + } + else + { + ec = asio::error_code(); + } + } + else + { + // Asynchronous operations have been started from more than one thread, + // so cancellation is not safe. + ec = asio::error::operation_not_supported; + } +#else // defined(ASIO_ENABLE_CANCELIO) + else + { + // Cancellation is not supported as CancelIo may not be used. + ec = asio::error::operation_not_supported; + } +#endif // defined(ASIO_ENABLE_CANCELIO) + + // Cancel any operations started via the reactor. + if (!ec) + { + select_reactor* r = static_cast<select_reactor*>( + interlocked_compare_exchange_pointer( + reinterpret_cast<void**>(&reactor_), 0, 0)); + if (r) + r->cancel_ops(impl.socket_, impl.reactor_data_); + } + + return ec; +} + +asio::error_code win_iocp_socket_service_base::do_open( + win_iocp_socket_service_base::base_implementation_type& impl, + int family, int type, int protocol, asio::error_code& ec) +{ + if (is_open(impl)) + { + ec = asio::error::already_open; + return ec; + } + + socket_holder sock(socket_ops::socket(family, type, protocol, ec)); + if (sock.get() == invalid_socket) + return ec; + + HANDLE sock_as_handle = reinterpret_cast<HANDLE>(sock.get()); + if (iocp_service_.register_handle(sock_as_handle, ec)) + return ec; + + impl.socket_ = sock.release(); + switch (type) + { + case SOCK_STREAM: impl.state_ = socket_ops::stream_oriented; break; + case SOCK_DGRAM: impl.state_ = socket_ops::datagram_oriented; break; + default: impl.state_ = 0; break; + } + impl.cancel_token_.reset(static_cast<void*>(0), socket_ops::noop_deleter()); + ec = asio::error_code(); + return ec; +} + +asio::error_code win_iocp_socket_service_base::do_assign( + win_iocp_socket_service_base::base_implementation_type& impl, + int type, socket_type native_socket, asio::error_code& ec) +{ + if (is_open(impl)) + { + ec = asio::error::already_open; + return ec; + } + + HANDLE sock_as_handle = reinterpret_cast<HANDLE>(native_socket); + if (iocp_service_.register_handle(sock_as_handle, ec)) + return ec; + + impl.socket_ = native_socket; + switch (type) + { + case SOCK_STREAM: impl.state_ = socket_ops::stream_oriented; break; + case SOCK_DGRAM: impl.state_ = socket_ops::datagram_oriented; break; + default: impl.state_ = 0; break; + } + impl.cancel_token_.reset(static_cast<void*>(0), socket_ops::noop_deleter()); + ec = asio::error_code(); + return ec; +} + +void win_iocp_socket_service_base::start_send_op( + win_iocp_socket_service_base::base_implementation_type& impl, + WSABUF* buffers, std::size_t buffer_count, + socket_base::message_flags flags, bool noop, operation* op) +{ + update_cancellation_thread_id(impl); + iocp_service_.work_started(); + + if (noop) + iocp_service_.on_completion(op); + else if (!is_open(impl)) + iocp_service_.on_completion(op, asio::error::bad_descriptor); + else + { + DWORD bytes_transferred = 0; + int result = ::WSASend(impl.socket_, buffers, + static_cast<DWORD>(buffer_count), &bytes_transferred, flags, op, 0); + DWORD last_error = ::WSAGetLastError(); + if (last_error == ERROR_PORT_UNREACHABLE) + last_error = WSAECONNREFUSED; + if (result != 0 && last_error != WSA_IO_PENDING) + iocp_service_.on_completion(op, last_error, bytes_transferred); + else + iocp_service_.on_pending(op); + } +} + +void win_iocp_socket_service_base::start_send_to_op( + win_iocp_socket_service_base::base_implementation_type& impl, + WSABUF* buffers, std::size_t buffer_count, + const socket_addr_type* addr, int addrlen, + socket_base::message_flags flags, operation* op) +{ + update_cancellation_thread_id(impl); + iocp_service_.work_started(); + + if (!is_open(impl)) + iocp_service_.on_completion(op, asio::error::bad_descriptor); + else + { + DWORD bytes_transferred = 0; + int result = ::WSASendTo(impl.socket_, buffers, + static_cast<DWORD>(buffer_count), + &bytes_transferred, flags, addr, addrlen, op, 0); + DWORD last_error = ::WSAGetLastError(); + if (last_error == ERROR_PORT_UNREACHABLE) + last_error = WSAECONNREFUSED; + if (result != 0 && last_error != WSA_IO_PENDING) + iocp_service_.on_completion(op, last_error, bytes_transferred); + else + iocp_service_.on_pending(op); + } +} + +void win_iocp_socket_service_base::start_receive_op( + win_iocp_socket_service_base::base_implementation_type& impl, + WSABUF* buffers, std::size_t buffer_count, + socket_base::message_flags flags, bool noop, operation* op) +{ + update_cancellation_thread_id(impl); + iocp_service_.work_started(); + + if (noop) + iocp_service_.on_completion(op); + else if (!is_open(impl)) + iocp_service_.on_completion(op, asio::error::bad_descriptor); + else + { + DWORD bytes_transferred = 0; + DWORD recv_flags = flags; + int result = ::WSARecv(impl.socket_, buffers, + static_cast<DWORD>(buffer_count), + &bytes_transferred, &recv_flags, op, 0); + DWORD last_error = ::WSAGetLastError(); + if (last_error == ERROR_NETNAME_DELETED) + last_error = WSAECONNRESET; + else if (last_error == ERROR_PORT_UNREACHABLE) + last_error = WSAECONNREFUSED; + if (result != 0 && last_error != WSA_IO_PENDING) + iocp_service_.on_completion(op, last_error, bytes_transferred); + else + iocp_service_.on_pending(op); + } +} + +void win_iocp_socket_service_base::start_null_buffers_receive_op( + win_iocp_socket_service_base::base_implementation_type& impl, + socket_base::message_flags flags, reactor_op* op) +{ + if ((impl.state_ & socket_ops::stream_oriented) != 0) + { + // For stream sockets on Windows, we may issue a 0-byte overlapped + // WSARecv to wait until there is data available on the socket. + ::WSABUF buf = { 0, 0 }; + start_receive_op(impl, &buf, 1, flags, false, op); + } + else + { + start_reactor_op(impl, + (flags & socket_base::message_out_of_band) + ? select_reactor::except_op : select_reactor::read_op, + op); + } +} + +void win_iocp_socket_service_base::start_receive_from_op( + win_iocp_socket_service_base::base_implementation_type& impl, + WSABUF* buffers, std::size_t buffer_count, socket_addr_type* addr, + socket_base::message_flags flags, int* addrlen, operation* op) +{ + update_cancellation_thread_id(impl); + iocp_service_.work_started(); + + if (!is_open(impl)) + iocp_service_.on_completion(op, asio::error::bad_descriptor); + else + { + DWORD bytes_transferred = 0; + DWORD recv_flags = flags; + int result = ::WSARecvFrom(impl.socket_, buffers, + static_cast<DWORD>(buffer_count), + &bytes_transferred, &recv_flags, addr, addrlen, op, 0); + DWORD last_error = ::WSAGetLastError(); + if (last_error == ERROR_PORT_UNREACHABLE) + last_error = WSAECONNREFUSED; + if (result != 0 && last_error != WSA_IO_PENDING) + iocp_service_.on_completion(op, last_error, bytes_transferred); + else + iocp_service_.on_pending(op); + } +} + +void win_iocp_socket_service_base::start_accept_op( + win_iocp_socket_service_base::base_implementation_type& impl, + bool peer_is_open, socket_holder& new_socket, int family, int type, + int protocol, void* output_buffer, DWORD address_length, operation* op) +{ + update_cancellation_thread_id(impl); + iocp_service_.work_started(); + + if (!is_open(impl)) + iocp_service_.on_completion(op, asio::error::bad_descriptor); + else if (peer_is_open) + iocp_service_.on_completion(op, asio::error::already_open); + else + { + asio::error_code ec; + new_socket.reset(socket_ops::socket(family, type, protocol, ec)); + if (new_socket.get() == invalid_socket) + iocp_service_.on_completion(op, ec); + else + { + DWORD bytes_read = 0; + BOOL result = ::AcceptEx(impl.socket_, new_socket.get(), output_buffer, + 0, address_length, address_length, &bytes_read, op); + DWORD last_error = ::WSAGetLastError(); + if (!result && last_error != WSA_IO_PENDING) + iocp_service_.on_completion(op, last_error); + else + iocp_service_.on_pending(op); + } + } +} + +void win_iocp_socket_service_base::restart_accept_op( + socket_type s, socket_holder& new_socket, int family, int type, + int protocol, void* output_buffer, DWORD address_length, operation* op) +{ + new_socket.reset(); + iocp_service_.work_started(); + + asio::error_code ec; + new_socket.reset(socket_ops::socket(family, type, protocol, ec)); + if (new_socket.get() == invalid_socket) + iocp_service_.on_completion(op, ec); + else + { + DWORD bytes_read = 0; + BOOL result = ::AcceptEx(s, new_socket.get(), output_buffer, + 0, address_length, address_length, &bytes_read, op); + DWORD last_error = ::WSAGetLastError(); + if (!result && last_error != WSA_IO_PENDING) + iocp_service_.on_completion(op, last_error); + else + iocp_service_.on_pending(op); + } +} + +void win_iocp_socket_service_base::start_reactor_op( + win_iocp_socket_service_base::base_implementation_type& impl, + int op_type, reactor_op* op) +{ + select_reactor& r = get_reactor(); + update_cancellation_thread_id(impl); + + if (is_open(impl)) + { + r.start_op(op_type, impl.socket_, impl.reactor_data_, op, false, false); + return; + } + else + op->ec_ = asio::error::bad_descriptor; + + iocp_service_.post_immediate_completion(op, false); +} + +void win_iocp_socket_service_base::start_connect_op( + win_iocp_socket_service_base::base_implementation_type& impl, + int family, int type, const socket_addr_type* addr, + std::size_t addrlen, win_iocp_socket_connect_op_base* op) +{ + // If ConnectEx is available, use that. + if (family == ASIO_OS_DEF(AF_INET) + || family == ASIO_OS_DEF(AF_INET6)) + { + if (connect_ex_fn connect_ex = get_connect_ex(impl, type)) + { + union address_union + { + socket_addr_type base; + sockaddr_in4_type v4; + sockaddr_in6_type v6; + } a; + + using namespace std; // For memset. + memset(&a, 0, sizeof(a)); + a.base.sa_family = family; + + socket_ops::bind(impl.socket_, &a.base, + family == ASIO_OS_DEF(AF_INET) + ? sizeof(a.v4) : sizeof(a.v6), op->ec_); + if (op->ec_ && op->ec_ != asio::error::invalid_argument) + { + iocp_service_.post_immediate_completion(op, false); + return; + } + + op->connect_ex_ = true; + update_cancellation_thread_id(impl); + iocp_service_.work_started(); + + BOOL result = connect_ex(impl.socket_, + addr, static_cast<int>(addrlen), 0, 0, 0, op); + DWORD last_error = ::WSAGetLastError(); + if (!result && last_error != WSA_IO_PENDING) + iocp_service_.on_completion(op, last_error); + else + iocp_service_.on_pending(op); + return; + } + } + + // Otherwise, fall back to a reactor-based implementation. + select_reactor& r = get_reactor(); + update_cancellation_thread_id(impl); + + if ((impl.state_ & socket_ops::non_blocking) != 0 + || socket_ops::set_internal_non_blocking( + impl.socket_, impl.state_, true, op->ec_)) + { + if (socket_ops::connect(impl.socket_, addr, addrlen, op->ec_) != 0) + { + if (op->ec_ == asio::error::in_progress + || op->ec_ == asio::error::would_block) + { + op->ec_ = asio::error_code(); + r.start_op(select_reactor::connect_op, impl.socket_, + impl.reactor_data_, op, false, false); + return; + } + } + } + + r.post_immediate_completion(op, false); +} + +void win_iocp_socket_service_base::close_for_destruction( + win_iocp_socket_service_base::base_implementation_type& impl) +{ + if (is_open(impl)) + { + ASIO_HANDLER_OPERATION((iocp_service_.context(), + "socket", &impl, impl.socket_, "close")); + + // Check if the reactor was created, in which case we need to close the + // socket on the reactor as well to cancel any operations that might be + // running there. + select_reactor* r = static_cast<select_reactor*>( + interlocked_compare_exchange_pointer( + reinterpret_cast<void**>(&reactor_), 0, 0)); + if (r) + r->deregister_descriptor(impl.socket_, impl.reactor_data_, true); + + asio::error_code ignored_ec; + socket_ops::close(impl.socket_, impl.state_, true, ignored_ec); + + if (r) + r->cleanup_descriptor_data(impl.reactor_data_); + } + + impl.socket_ = invalid_socket; + impl.state_ = 0; + impl.cancel_token_.reset(); +#if defined(ASIO_ENABLE_CANCELIO) + impl.safe_cancellation_thread_id_ = 0; +#endif // defined(ASIO_ENABLE_CANCELIO) +} + +void win_iocp_socket_service_base::update_cancellation_thread_id( + win_iocp_socket_service_base::base_implementation_type& impl) +{ +#if defined(ASIO_ENABLE_CANCELIO) + if (impl.safe_cancellation_thread_id_ == 0) + impl.safe_cancellation_thread_id_ = ::GetCurrentThreadId(); + else if (impl.safe_cancellation_thread_id_ != ::GetCurrentThreadId()) + impl.safe_cancellation_thread_id_ = ~DWORD(0); +#else // defined(ASIO_ENABLE_CANCELIO) + (void)impl; +#endif // defined(ASIO_ENABLE_CANCELIO) +} + +select_reactor& win_iocp_socket_service_base::get_reactor() +{ + select_reactor* r = static_cast<select_reactor*>( + interlocked_compare_exchange_pointer( + reinterpret_cast<void**>(&reactor_), 0, 0)); + if (!r) + { + r = &(use_service<select_reactor>(io_context_)); + interlocked_exchange_pointer(reinterpret_cast<void**>(&reactor_), r); + } + return *r; +} + +win_iocp_socket_service_base::connect_ex_fn +win_iocp_socket_service_base::get_connect_ex( + win_iocp_socket_service_base::base_implementation_type& impl, int type) +{ +#if defined(ASIO_DISABLE_CONNECTEX) + (void)impl; + (void)type; + return 0; +#else // defined(ASIO_DISABLE_CONNECTEX) + if (type != ASIO_OS_DEF(SOCK_STREAM) + && type != ASIO_OS_DEF(SOCK_SEQPACKET)) + return 0; + + void* ptr = interlocked_compare_exchange_pointer(&connect_ex_, 0, 0); + if (!ptr) + { + GUID guid = { 0x25a207b9, 0xddf3, 0x4660, + { 0x8e, 0xe9, 0x76, 0xe5, 0x8c, 0x74, 0x06, 0x3e } }; + + DWORD bytes = 0; + if (::WSAIoctl(impl.socket_, SIO_GET_EXTENSION_FUNCTION_POINTER, + &guid, sizeof(guid), &ptr, sizeof(ptr), &bytes, 0, 0) != 0) + { + // Set connect_ex_ to a special value to indicate that ConnectEx is + // unavailable. That way we won't bother trying to look it up again. + ptr = this; + } + + interlocked_exchange_pointer(&connect_ex_, ptr); + } + + return reinterpret_cast<connect_ex_fn>(ptr == this ? 0 : ptr); +#endif // defined(ASIO_DISABLE_CONNECTEX) +} + +win_iocp_socket_service_base::nt_set_info_fn +win_iocp_socket_service_base::get_nt_set_info() +{ + void* ptr = interlocked_compare_exchange_pointer(&nt_set_info_, 0, 0); + if (!ptr) + { + if (HMODULE h = ::GetModuleHandleA("NTDLL.DLL")) + ptr = reinterpret_cast<void*>(GetProcAddress(h, "NtSetInformationFile")); + + // On failure, set nt_set_info_ to a special value to indicate that the + // NtSetInformationFile function is unavailable. That way we won't bother + // trying to look it up again. + interlocked_exchange_pointer(&nt_set_info_, ptr ? ptr : this); + } + + return reinterpret_cast<nt_set_info_fn>(ptr == this ? 0 : ptr); +} + +void* win_iocp_socket_service_base::interlocked_compare_exchange_pointer( + void** dest, void* exch, void* cmp) +{ +#if defined(_M_IX86) + return reinterpret_cast<void*>(InterlockedCompareExchange( + reinterpret_cast<PLONG>(dest), reinterpret_cast<LONG>(exch), + reinterpret_cast<LONG>(cmp))); +#else + return InterlockedCompareExchangePointer(dest, exch, cmp); +#endif +} + +void* win_iocp_socket_service_base::interlocked_exchange_pointer( + void** dest, void* val) +{ +#if defined(_M_IX86) + return reinterpret_cast<void*>(InterlockedExchange( + reinterpret_cast<PLONG>(dest), reinterpret_cast<LONG>(val))); +#else + return InterlockedExchangePointer(dest, val); +#endif +} + +} // namespace detail +} // namespace asio + +#include "asio/detail/pop_options.hpp" + +#endif // defined(ASIO_HAS_IOCP) + +#endif // ASIO_DETAIL_IMPL_WIN_IOCP_SOCKET_SERVICE_BASE_IPP |