1 files changed, 644 insertions, 0 deletions
diff --git a/src/net/fd_windows.go b/src/net/fd_windows.go
new file mode 100644
index 000000000..6d69e0624
--- /dev/null
+++ b/src/net/fd_windows.go
@@ -0,0 +1,644 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package net
+
+import (
+	"errors"
+	"io"
+	"os"
+	"runtime"
+	"sync"
+	"syscall"
+	"time"
+	"unsafe"
+)
+
+var (
+	initErr error
+	ioSync  uint64
+)
+
+// CancelIo Windows API cancels all outstanding IO for a particular
+// socket on current thread. To overcome that limitation, we run
+// special goroutine, locked to OS single thread, that both starts
+// and cancels IO. It means, there are 2 unavoidable thread switches
+// for every IO.
+// Some newer versions of Windows has new CancelIoEx API, that does
+// not have that limitation and can be used from any thread. This
+// package uses CancelIoEx API, if present, otherwise it fallback
+// to CancelIo.
+
+var (
+	canCancelIO                               bool // determines if CancelIoEx API is present
+	skipSyncNotif                             bool
+	hasLoadSetFileCompletionNotificationModes bool
+)
+
+func sysInit() {
+	var d syscall.WSAData
+	e := syscall.WSAStartup(uint32(0x202), &d)
+	if e != nil {
+		initErr = os.NewSyscallError("WSAStartup", e)
+	}
+	canCancelIO = syscall.LoadCancelIoEx() == nil
+	if syscall.LoadGetAddrInfo() == nil {
+		lookupPort = newLookupPort
+		lookupIP = newLookupIP
+	}
+
+	hasLoadSetFileCompletionNotificationModes = syscall.LoadSetFileCompletionNotificationModes() == nil
+	if hasLoadSetFileCompletionNotificationModes {
+		// It's not safe to use FILE_SKIP_COMPLETION_PORT_ON_SUCCESS if non IFS providers are installed:
+		// http://support.microsoft.com/kb/2568167
+		skipSyncNotif = true
+		protos := [2]int32{syscall.IPPROTO_TCP, 0}
+		var buf [32]syscall.WSAProtocolInfo
+		len := uint32(unsafe.Sizeof(buf))
+		n, err := syscall.WSAEnumProtocols(&protos[0], &buf[0], &len)
+		if err != nil {
+			skipSyncNotif = false
+		} else {
+			for i := int32(0); i < n; i++ {
+				if buf[i].ServiceFlags1&syscall.XP1_IFS_HANDLES == 0 {
+					skipSyncNotif = false
+					break
+				}
+			}
+		}
+	}
+}
+
+func closesocket(s syscall.Handle) error {
+	return syscall.Closesocket(s)
+}
+
+func canUseConnectEx(net string) bool {
+	switch net {
+	case "udp", "udp4", "udp6", "ip", "ip4", "ip6":
+		// ConnectEx windows API does not support connectionless sockets.
+		return false
+	}
+	return syscall.LoadConnectEx() == nil
+}
+
+func dial(net string, ra Addr, dialer func(time.Time) (Conn, error), deadline time.Time) (Conn, error) {
+	if !canUseConnectEx(net) {
+		// Use the relatively inefficient goroutine-racing
+		// implementation of DialTimeout.
+		return dialChannel(net, ra, dialer, deadline)
+	}
+	return dialer(deadline)
+}
+
+// operation contains superset of data necessary to perform all async IO.
+type operation struct {
+	// Used by IOCP interface, it must be first field
+	// of the struct, as our code rely on it.
+	o syscall.Overlapped
+
+	// fields used by runtime.netpoll
+	runtimeCtx uintptr
+	mode       int32
+	errno      int32
+	qty        uint32
+
+	// fields used only by net package
+	fd     *netFD
+	errc   chan error
+	buf    syscall.WSABuf
+	sa     syscall.Sockaddr
+	rsa    *syscall.RawSockaddrAny
+	rsan   int32
+	handle syscall.Handle
+	flags  uint32
+}
+
+func (o *operation) InitBuf(buf []byte) {
+	o.buf.Len = uint32(len(buf))
+	o.buf.Buf = nil
+	if len(buf) != 0 {
+		o.buf.Buf = &buf[0]
+	}
+}
+
+// ioSrv executes net IO requests.
+type ioSrv struct {
+	req chan ioSrvReq
+}
+
+type ioSrvReq struct {
+	o      *operation
+	submit func(o *operation) error // if nil, cancel the operation
+}
+
+// ProcessRemoteIO will execute submit IO requests on behalf
+// of other goroutines, all on a single os thread, so it can
+// cancel them later. Results of all operations will be sent
+// back to their requesters via channel supplied in request.
+// It is used only when the CancelIoEx API is unavailable.
+func (s *ioSrv) ProcessRemoteIO() {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+	for r := range s.req {
+		if r.submit != nil {
+			r.o.errc <- r.submit(r.o)
+		} else {
+			r.o.errc <- syscall.CancelIo(r.o.fd.sysfd)
+		}
+	}
+}
+
+// ExecIO executes a single IO operation o. It submits and cancels
+// IO in the current thread for systems where Windows CancelIoEx API
+// is available. Alternatively, it passes the request onto
+// runtime netpoll and waits for completion or cancels request.
+func (s *ioSrv) ExecIO(o *operation, name string, submit func(o *operation) error) (int, error) {
+	fd := o.fd
+	// Notify runtime netpoll about starting IO.
+	err := fd.pd.Prepare(int(o.mode))
+	if err != nil {
+		return 0, &OpError{name, fd.net, fd.laddr, err}
+	}
+	// Start IO.
+	if canCancelIO {
+		err = submit(o)
+	} else {
+		// Send request to a special dedicated thread,
+		// so it can stop the IO with CancelIO later.
+		s.req <- ioSrvReq{o, submit}
+		err = <-o.errc
+	}
+	switch err {
+	case nil:
+		// IO completed immediately
+		if o.fd.skipSyncNotif {
+			// No completion message will follow, so return immediately.
+			return int(o.qty), nil
+		}
+		// Need to get our completion message anyway.
+	case syscall.ERROR_IO_PENDING:
+		// IO started, and we have to wait for its completion.
+		err = nil
+	default:
+		return 0, &OpError{name, fd.net, fd.laddr, err}
+	}
+	// Wait for our request to complete.
+	err = fd.pd.Wait(int(o.mode))
+	if err == nil {
+		// All is good. Extract our IO results and return.
+		if o.errno != 0 {
+			err = syscall.Errno(o.errno)
+			return 0, &OpError{name, fd.net, fd.laddr, err}
+		}
+		return int(o.qty), nil
+	}
+	// IO is interrupted by "close" or "timeout"
+	netpollErr := err
+	switch netpollErr {
+	case errClosing, errTimeout:
+		// will deal with those.
+	default:
+		panic("net: unexpected runtime.netpoll error: " + netpollErr.Error())
+	}
+	// Cancel our request.
+	if canCancelIO {
+		err := syscall.CancelIoEx(fd.sysfd, &o.o)
+		// Assuming ERROR_NOT_FOUND is returned, if IO is completed.
+		if err != nil && err != syscall.ERROR_NOT_FOUND {
+			// TODO(brainman): maybe do something else, but panic.
+			panic(err)
+		}
+	} else {
+		s.req <- ioSrvReq{o, nil}
+		<-o.errc
+	}
+	// Wait for cancellation to complete.
+	fd.pd.WaitCanceled(int(o.mode))
+	if o.errno != 0 {
+		err = syscall.Errno(o.errno)
+		if err == syscall.ERROR_OPERATION_ABORTED { // IO Canceled
+			err = netpollErr
+		}
+		return 0, &OpError{name, fd.net, fd.laddr, err}
+	}
+	// We issued cancellation request. But, it seems, IO operation succeeded
+	// before cancellation request run. We need to treat IO operation as
+	// succeeded (the bytes are actually sent/recv from network).
+	return int(o.qty), nil
+}
+
+// Start helper goroutines.
+var rsrv, wsrv *ioSrv
+var onceStartServer sync.Once
+
+func startServer() {
+	rsrv = new(ioSrv)
+	wsrv = new(ioSrv)
+	if !canCancelIO {
+		// Only CancelIo API is available. Lets start two special goroutines
+		// locked to an OS thread, that both starts and cancels IO. One will
+		// process read requests, while other will do writes.
+		rsrv.req = make(chan ioSrvReq)
+		go rsrv.ProcessRemoteIO()
+		wsrv.req = make(chan ioSrvReq)
+		go wsrv.ProcessRemoteIO()
+	}
+}
+
+// Network file descriptor.
+type netFD struct {
+	// locking/lifetime of sysfd + serialize access to Read and Write methods
+	fdmu fdMutex
+
+	// immutable until Close
+	sysfd         syscall.Handle
+	family        int
+	sotype        int
+	isConnected   bool
+	skipSyncNotif bool
+	net           string
+	laddr         Addr
+	raddr         Addr
+
+	rop operation // read operation
+	wop operation // write operation
+
+	// wait server
+	pd pollDesc
+}
+
+func newFD(sysfd syscall.Handle, family, sotype int, net string) (*netFD, error) {
+	if initErr != nil {
+		return nil, initErr
+	}
+	onceStartServer.Do(startServer)
+	return &netFD{sysfd: sysfd, family: family, sotype: sotype, net: net}, nil
+}
+
+func (fd *netFD) init() error {
+	if err := fd.pd.Init(fd); err != nil {
+		return err
+	}
+	if hasLoadSetFileCompletionNotificationModes {
+		// We do not use events, so we can skip them always.
+		flags := uint8(syscall.FILE_SKIP_SET_EVENT_ON_HANDLE)
+		// It's not safe to skip completion notifications for UDP:
+		// http://blogs.technet.com/b/winserverperformance/archive/2008/06/26/designing-applications-for-high-performance-part-iii.aspx
+		if skipSyncNotif && fd.net == "tcp" {
+			flags |= syscall.FILE_SKIP_COMPLETION_PORT_ON_SUCCESS
+		}
+		err := syscall.SetFileCompletionNotificationModes(fd.sysfd, flags)
+		if err == nil && flags&syscall.FILE_SKIP_COMPLETION_PORT_ON_SUCCESS != 0 {
+			fd.skipSyncNotif = true
+		}
+	}
+	fd.rop.mode = 'r'
+	fd.wop.mode = 'w'
+	fd.rop.fd = fd
+	fd.wop.fd = fd
+	fd.rop.runtimeCtx = fd.pd.runtimeCtx
+	fd.wop.runtimeCtx = fd.pd.runtimeCtx
+	if !canCancelIO {
+		fd.rop.errc = make(chan error)
+		fd.wop.errc = make(chan error)
+	}
+	return nil
+}
+
+func (fd *netFD) setAddr(laddr, raddr Addr) {
+	fd.laddr = laddr
+	fd.raddr = raddr
+	runtime.SetFinalizer(fd, (*netFD).Close)
+}
+
+func (fd *netFD) connect(la, ra syscall.Sockaddr, deadline time.Time) error {
+	// Do not need to call fd.writeLock here,
+	// because fd is not yet accessible to user,
+	// so no concurrent operations are possible.
+	if err := fd.init(); err != nil {
+		return err
+	}
+	if !deadline.IsZero() {
+		fd.setWriteDeadline(deadline)
+		defer fd.setWriteDeadline(noDeadline)
+	}
+	if !canUseConnectEx(fd.net) {
+		return syscall.Connect(fd.sysfd, ra)
+	}
+	// ConnectEx windows API requires an unconnected, previously bound socket.
+	if la == nil {
+		switch ra.(type) {
+		case *syscall.SockaddrInet4:
+			la = &syscall.SockaddrInet4{}
+		case *syscall.SockaddrInet6:
+			la = &syscall.SockaddrInet6{}
+		default:
+			panic("unexpected type in connect")
+		}
+		if err := syscall.Bind(fd.sysfd, la); err != nil {
+			return err
+		}
+	}
+	// Call ConnectEx API.
+	o := &fd.wop
+	o.sa = ra
+	_, err := wsrv.ExecIO(o, "ConnectEx", func(o *operation) error {
+		return syscall.ConnectEx(o.fd.sysfd, o.sa, nil, 0, nil, &o.o)
+	})
+	if err != nil {
+		return err
+	}
+	// Refresh socket properties.
+	return syscall.Setsockopt(fd.sysfd, syscall.SOL_SOCKET, syscall.SO_UPDATE_CONNECT_CONTEXT, (*byte)(unsafe.Pointer(&fd.sysfd)), int32(unsafe.Sizeof(fd.sysfd)))
+}
+
+func (fd *netFD) destroy() {
+	if fd.sysfd == syscall.InvalidHandle {
+		return
+	}
+	// Poller may want to unregister fd in readiness notification mechanism,
+	// so this must be executed before closesocket.
+	fd.pd.Close()
+	closesocket(fd.sysfd)
+	fd.sysfd = syscall.InvalidHandle
+	// no need for a finalizer anymore
+	runtime.SetFinalizer(fd, nil)
+}
+
+// Add a reference to this fd.
+// Returns an error if the fd cannot be used.
+func (fd *netFD) incref() error {
+	if !fd.fdmu.Incref() {
+		return errClosing
+	}
+	return nil
+}
+
+// Remove a reference to this FD and close if we've been asked to do so
+// (and there are no references left).
+func (fd *netFD) decref() {
+	if fd.fdmu.Decref() {
+		fd.destroy()
+	}
+}
+
+// Add a reference to this fd and lock for reading.
+// Returns an error if the fd cannot be used.
+func (fd *netFD) readLock() error {
+	if !fd.fdmu.RWLock(true) {
+		return errClosing
+	}
+	return nil
+}
+
+// Unlock for reading and remove a reference to this FD.
+func (fd *netFD) readUnlock() {
+	if fd.fdmu.RWUnlock(true) {
+		fd.destroy()
+	}
+}
+
+// Add a reference to this fd and lock for writing.
+// Returns an error if the fd cannot be used.
+func (fd *netFD) writeLock() error {
+	if !fd.fdmu.RWLock(false) {
+		return errClosing
+	}
+	return nil
+}
+
+// Unlock for writing and remove a reference to this FD.
+func (fd *netFD) writeUnlock() {
+	if fd.fdmu.RWUnlock(false) {
+		fd.destroy()
+	}
+}
+
+func (fd *netFD) Close() error {
+	if !fd.fdmu.IncrefAndClose() {
+		return errClosing
+	}
+	// unblock pending reader and writer
+	fd.pd.Evict()
+	fd.decref()
+	return nil
+}
+
+func (fd *netFD) shutdown(how int) error {
+	if err := fd.incref(); err != nil {
+		return err
+	}
+	defer fd.decref()
+	err := syscall.Shutdown(fd.sysfd, how)
+	if err != nil {
+		return &OpError{"shutdown", fd.net, fd.laddr, err}
+	}
+	return nil
+}
+
+func (fd *netFD) closeRead() error {
+	return fd.shutdown(syscall.SHUT_RD)
+}
+
+func (fd *netFD) closeWrite() error {
+	return fd.shutdown(syscall.SHUT_WR)
+}
+
+func (fd *netFD) Read(buf []byte) (int, error) {
+	if err := fd.readLock(); err != nil {
+		return 0, err
+	}
+	defer fd.readUnlock()
+	o := &fd.rop
+	o.InitBuf(buf)
+	n, err := rsrv.ExecIO(o, "WSARecv", func(o *operation) error {
+		return syscall.WSARecv(o.fd.sysfd, &o.buf, 1, &o.qty, &o.flags, &o.o, nil)
+	})
+	if err == nil && n == 0 {
+		err = io.EOF
+	}
+	if raceenabled {
+		raceAcquire(unsafe.Pointer(&ioSync))
+	}
+	return n, err
+}
+
+func (fd *netFD) readFrom(buf []byte) (n int, sa syscall.Sockaddr, err error) {
+	if len(buf) == 0 {
+		return 0, nil, nil
+	}
+	if err := fd.readLock(); err != nil {
+		return 0, nil, err
+	}
+	defer fd.readUnlock()
+	o := &fd.rop
+	o.InitBuf(buf)
+	n, err = rsrv.ExecIO(o, "WSARecvFrom", func(o *operation) error {
+		if o.rsa == nil {
+			o.rsa = new(syscall.RawSockaddrAny)
+		}
+		o.rsan = int32(unsafe.Sizeof(*o.rsa))
+		return syscall.WSARecvFrom(o.fd.sysfd, &o.buf, 1, &o.qty, &o.flags, o.rsa, &o.rsan, &o.o, nil)
+	})
+	if err != nil {
+		return 0, nil, err
+	}
+	sa, _ = o.rsa.Sockaddr()
+	return
+}
+
+func (fd *netFD) Write(buf []byte) (int, error) {
+	if err := fd.writeLock(); err != nil {
+		return 0, err
+	}
+	defer fd.writeUnlock()
+	if raceenabled {
+		raceReleaseMerge(unsafe.Pointer(&ioSync))
+	}
+	o := &fd.wop
+	o.InitBuf(buf)
+	return wsrv.ExecIO(o, "WSASend", func(o *operation) error {
+		return syscall.WSASend(o.fd.sysfd, &o.buf, 1, &o.qty, 0, &o.o, nil)
+	})
+}
+
+func (fd *netFD) writeTo(buf []byte, sa syscall.Sockaddr) (int, error) {
+	if len(buf) == 0 {
+		return 0, nil
+	}
+	if err := fd.writeLock(); err != nil {
+		return 0, err
+	}
+	defer fd.writeUnlock()
+	o := &fd.wop
+	o.InitBuf(buf)
+	o.sa = sa
+	return wsrv.ExecIO(o, "WSASendto", func(o *operation) error {
+		return syscall.WSASendto(o.fd.sysfd, &o.buf, 1, &o.qty, 0, o.sa, &o.o, nil)
+	})
+}
+
+func (fd *netFD) acceptOne(rawsa []syscall.RawSockaddrAny, o *operation) (*netFD, error) {
+	// Get new socket.
+	s, err := sysSocket(fd.family, fd.sotype, 0)
+	if err != nil {
+		return nil, &OpError{"socket", fd.net, fd.laddr, err}
+	}
+
+	// Associate our new socket with IOCP.
+	netfd, err := newFD(s, fd.family, fd.sotype, fd.net)
+	if err != nil {
+		closesocket(s)
+		return nil, &OpError{"accept", fd.net, fd.laddr, err}
+	}
+	if err := netfd.init(); err != nil {
+		fd.Close()
+		return nil, err
+	}
+
+	// Submit accept request.
+	o.handle = s
+	o.rsan = int32(unsafe.Sizeof(rawsa[0]))
+	_, err = rsrv.ExecIO(o, "AcceptEx", func(o *operation) error {
+		return syscall.AcceptEx(o.fd.sysfd, o.handle, (*byte)(unsafe.Pointer(&rawsa[0])), 0, uint32(o.rsan), uint32(o.rsan), &o.qty, &o.o)
+	})
+	if err != nil {
+		netfd.Close()
+		return nil, err
+	}
+
+	// Inherit properties of the listening socket.
+	err = syscall.Setsockopt(s, syscall.SOL_SOCKET, syscall.SO_UPDATE_ACCEPT_CONTEXT, (*byte)(unsafe.Pointer(&fd.sysfd)), int32(unsafe.Sizeof(fd.sysfd)))
+	if err != nil {
+		netfd.Close()
+		return nil, &OpError{"Setsockopt", fd.net, fd.laddr, err}
+	}
+
+	return netfd, nil
+}
+
+func (fd *netFD) accept() (*netFD, error) {
+	if err := fd.readLock(); err != nil {
+		return nil, err
+	}
+	defer fd.readUnlock()
+
+	o := &fd.rop
+	var netfd *netFD
+	var err error
+	var rawsa [2]syscall.RawSockaddrAny
+	for {
+		netfd, err = fd.acceptOne(rawsa[:], o)
+		if err == nil {
+			break
+		}
+		// Sometimes we see WSAECONNRESET and ERROR_NETNAME_DELETED is
+		// returned here. These happen if connection reset is received
+		// before AcceptEx could complete. These errors relate to new
+		// connection, not to AcceptEx, so ignore broken connection and
+		// try AcceptEx again for more connections.
+		operr, ok := err.(*OpError)
+		if !ok {
+			return nil, err
+		}
+		errno, ok := operr.Err.(syscall.Errno)
+		if !ok {
+			return nil, err
+		}
+		switch errno {
+		case syscall.ERROR_NETNAME_DELETED, syscall.WSAECONNRESET:
+			// ignore these and try again
+		default:
+			return nil, err
+		}
+	}
+
+	// Get local and peer addr out of AcceptEx buffer.
+	var lrsa, rrsa *syscall.RawSockaddrAny
+	var llen, rlen int32
+	syscall.GetAcceptExSockaddrs((*byte)(unsafe.Pointer(&rawsa[0])),
+		0, uint32(o.rsan), uint32(o.rsan), &lrsa, &llen, &rrsa, &rlen)
+	lsa, _ := lrsa.Sockaddr()
+	rsa, _ := rrsa.Sockaddr()
+
+	netfd.setAddr(netfd.addrFunc()(lsa), netfd.addrFunc()(rsa))
+	return netfd, nil
+}
+
+func skipRawSocketTests() (skip bool, skipmsg string, err error) {
+	// From http://msdn.microsoft.com/en-us/library/windows/desktop/ms740548.aspx:
+	// Note: To use a socket of type SOCK_RAW requires administrative privileges.
+	// Users running Winsock applications that use raw sockets must be a member of
+	// the Administrators group on the local computer, otherwise raw socket calls
+	// will fail with an error code of WSAEACCES. On Windows Vista and later, access
+	// for raw sockets is enforced at socket creation. In earlier versions of Windows,
+	// access for raw sockets is enforced during other socket operations.
+	s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_RAW, 0)
+	if err == syscall.WSAEACCES {
+		return true, "skipping test; no access to raw socket allowed", nil
+	}
+	if err != nil {
+		return true, "", err
+	}
+	defer syscall.Closesocket(s)
+	return false, "", nil
+}
+
+// Unimplemented functions.
+
+func (fd *netFD) dup() (*os.File, error) {
+	// TODO: Implement this
+	return nil, os.NewSyscallError("dup", syscall.EWINDOWS)
+}
+
+var errNoSupport = errors.New("address family not supported")
+
+func (fd *netFD) readMsg(p []byte, oob []byte) (n, oobn, flags int, sa syscall.Sockaddr, err error) {
+	return 0, 0, 0, nil, errNoSupport
+}
+
+func (fd *netFD) writeMsg(p []byte, oob []byte, sa syscall.Sockaddr) (n int, oobn int, err error) {
+	return 0, 0, errNoSupport
+}