Added HV Socket known IDs, Dial, bug fixes (#239)

* Added HV Socket known IDs, Dial, bug fixes Added: * Well-know Hyper-V VMIDs for parents, children, and loopback. * VSock interop service GUID. * `Dial()` and `DialContext()` to dial a specific Hyper-V socket at a known address (along with a corresponding `HvsockDialer` struct. Bug fixes: * Dial (and Listen) now properly initialize and set properties of their sockets after ConnectEx (and AcceptEx). * The `socketError` used by `bind` was incorrect, it should be `int32(-1)`, not `uintptr(^0)` * Return errors for `(*HvsockConn) SetDeadline` Created a `sockets` package, currently only with syscalls to `Bind`, `ConnectEx` and `GetSockName`, bypassing `syscall/windows` restrictions on the types that can do so. Signed-off-by: Hamza El-Saawy <hamzaelsaawy@microsoft.com> * PR: error handling bug, rebase, unexport, naming * comments and todos statements * spelling * removed dead code * changed names to be more conventional * unexported socket code * made `(*HvsockDialer) Dial` take `Context`, removed `DialContext` * added default `Dial` function * rebased onto main * cleaned up `Dial(` retry loop Signed-off-by: Hamza El-Saawy <hamzaelsaawy@microsoft.com> * PR: RawSockaddr validation, `.As(` style Signed-off-by: Hamza El-Saawy <hamzaelsaawy@microsoft.com>
2026-09-01 14:47:32 -04:00 · 2022-07-21 19:33:50 -04:00
parent c62166d832
commit d68e55cd0b
6 changed files with 534 additions and 40 deletions
@@ -0,0 +1,20 @@
+package socket
+
+import (
+	"unsafe"
+)
+
+// RawSockaddr allows structs to be used with [Bind] and [ConnectEx]. The
+// struct must meet the Win32 sockaddr requirements specified here:
+// https://docs.microsoft.com/en-us/windows/win32/winsock/sockaddr-2
+//
+// Specifically, the struct size must be least larger than an int16 (unsigned short)
+// for the address family.
+type RawSockaddr interface {
+	// Sockaddr returns a pointer to the RawSockaddr and its struct size, allowing
+	// for the RawSockaddr's data to be overwritten by syscalls (if necessary).
+	//
+	// It is the callers responsibility to validate that the values are valid; invalid
+	// pointers or size can cause a panic.
+	Sockaddr() (unsafe.Pointer, int32, error)
+}
@@ -0,0 +1,153 @@
+//go:build windows
+
+package socket
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"sync"
+	"syscall"
+	"unsafe"
+
+	"github.com/Microsoft/go-winio/pkg/guid"
+	"golang.org/x/sys/windows"
+)
+
+//go:generate go run golang.org/x/sys/windows/mkwinsyscall -output zsyscall_windows.go socket.go
+
+//sys getsockname(s windows.Handle, name unsafe.Pointer, namelen *int32) (err error) [failretval==socketError] = ws2_32.getsockname
+//sys getpeername(s windows.Handle, name unsafe.Pointer, namelen *int32) (err error) [failretval==socketError] = ws2_32.getpeername
+//sys bind(s windows.Handle, name unsafe.Pointer, namelen int32) (err error) [failretval==socketError] = ws2_32.bind
+
+const socketError = uintptr(^uint32(0))
+
+var (
+	// todo(helsaawy): create custom error types to store the desired vs actual size and addr family?
+
+	ErrBufferSize     = errors.New("buffer size")
+	ErrAddrFamily     = errors.New("address family")
+	ErrInvalidPointer = errors.New("invalid pointer")
+	ErrSocketClosed   = fmt.Errorf("socket closed: %w", net.ErrClosed)
+)
+
+// todo(helsaawy): replace these with generics, ie: GetSockName[S RawSockaddr](s windows.Handle) (S, error)
+
+// GetSockName writes the local address of socket s to the [RawSockaddr] rsa.
+// If rsa is not large enough, the [windows.WSAEFAULT] is returned.
+func GetSockName(s windows.Handle, rsa RawSockaddr) error {
+	ptr, l, err := rsa.Sockaddr()
+	if err != nil {
+		return fmt.Errorf("could not retrieve socket pointer and size: %w", err)
+	}
+
+	// although getsockname returns WSAEFAULT if the buffer is too small, it does not set
+	// &l to the correct size, so--apart from doubling the buffer repeatedly--there is no remedy
+	return getsockname(s, ptr, &l)
+}
+
+// GetPeerName returns the remote address the socket is connected to.
+//
+// See [GetSockName] for more information.
+func GetPeerName(s windows.Handle, rsa RawSockaddr) error {
+	ptr, l, err := rsa.Sockaddr()
+	if err != nil {
+		return fmt.Errorf("could not retrieve socket pointer and size: %w", err)
+	}
+
+	return getpeername(s, ptr, &l)
+}
+
+func Bind(s windows.Handle, rsa RawSockaddr) (err error) {
+	ptr, l, err := rsa.Sockaddr()
+	if err != nil {
+		return fmt.Errorf("could not retrieve socket pointer and size: %w", err)
+	}
+
+	return bind(s, ptr, l)
+}
+
+// "golang.org/x/sys/windows".ConnectEx and .Bind only accept internal implementations of the
+// their sockaddr interface, so they cannot be used with HvsockAddr
+// Replicate functionality here from
+// https://cs.opensource.google/go/x/sys/+/master:windows/syscall_windows.go
+
+// The function pointers to `AcceptEx`, `ConnectEx` and `GetAcceptExSockaddrs` must be loaded at
+// runtime via a WSAIoctl call:
+// https://docs.microsoft.com/en-us/windows/win32/api/Mswsock/nc-mswsock-lpfn_connectex#remarks
+
+type runtimeFunc struct {
+	id   guid.GUID
+	once sync.Once
+	addr uintptr
+	err  error
+}
+
+func (f *runtimeFunc) Load() error {
+	f.once.Do(func() {
+		var s windows.Handle
+		s, f.err = windows.Socket(windows.AF_INET, windows.SOCK_STREAM, windows.IPPROTO_TCP)
+		if f.err != nil {
+			return
+		}
+		defer windows.CloseHandle(s) //nolint:errcheck
+
+		var n uint32
+		f.err = windows.WSAIoctl(s,
+			windows.SIO_GET_EXTENSION_FUNCTION_POINTER,
+			(*byte)(unsafe.Pointer(&f.id)),
+			uint32(unsafe.Sizeof(f.id)),
+			(*byte)(unsafe.Pointer(&f.addr)),
+			uint32(unsafe.Sizeof(f.addr)),
+			&n,
+			nil, //overlapped
+			0,   //completionRoutine
+		)
+	})
+	return f.err
+}
+
+var (
+	// todo: add `AcceptEx` and `GetAcceptExSockaddrs`
+	WSAID_CONNECTEX = guid.GUID{ //nolint:revive,stylecheck
+		Data1: 0x25a207b9,
+		Data2: 0xddf3,
+		Data3: 0x4660,
+		Data4: [8]byte{0x8e, 0xe9, 0x76, 0xe5, 0x8c, 0x74, 0x06, 0x3e},
+	}
+
+	connectExFunc = runtimeFunc{id: WSAID_CONNECTEX}
+)
+
+func ConnectEx(fd windows.Handle, rsa RawSockaddr, sendBuf *byte, sendDataLen uint32, bytesSent *uint32, overlapped *windows.Overlapped) error {
+	if err := connectExFunc.Load(); err != nil {
+		return fmt.Errorf("failed to load ConnectEx function pointer: %w", err)
+	}
+	ptr, n, err := rsa.Sockaddr()
+	if err != nil {
+		return err
+	}
+	return connectEx(fd, ptr, n, sendBuf, sendDataLen, bytesSent, overlapped)
+}
+
+// BOOL LpfnConnectex(
+//   [in]           SOCKET s,
+//   [in]           const sockaddr *name,
+//   [in]           int namelen,
+//   [in, optional] PVOID lpSendBuffer,
+//   [in]           DWORD dwSendDataLength,
+//   [out]          LPDWORD lpdwBytesSent,
+//   [in]           LPOVERLAPPED lpOverlapped
+// )
+func connectEx(s windows.Handle, name unsafe.Pointer, namelen int32, sendBuf *byte, sendDataLen uint32, bytesSent *uint32, overlapped *windows.Overlapped) (err error) {
+	// todo: after upgrading to 1.18, switch from syscall.Syscall9 to syscall.SyscallN
+	r1, _, e1 := syscall.Syscall9(connectExFunc.addr, 7, uintptr(s), uintptr(name), uintptr(namelen), uintptr(unsafe.Pointer(sendBuf)), uintptr(sendDataLen), uintptr(unsafe.Pointer(bytesSent)), uintptr(unsafe.Pointer(overlapped)), 0, 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = error(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
@@ -0,0 +1,70 @@
+// Code generated by 'go generate'; DO NOT EDIT.
+
+package socket
+
+import (
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+var _ unsafe.Pointer
+
+// Do the interface allocations only once for common
+// Errno values.
+const (
+	errnoERROR_IO_PENDING = 997
+)
+
+var (
+	errERROR_IO_PENDING error = syscall.Errno(errnoERROR_IO_PENDING)
+	errERROR_EINVAL     error = syscall.EINVAL
+)
+
+// errnoErr returns common boxed Errno values, to prevent
+// allocations at runtime.
+func errnoErr(e syscall.Errno) error {
+	switch e {
+	case 0:
+		return errERROR_EINVAL
+	case errnoERROR_IO_PENDING:
+		return errERROR_IO_PENDING
+	}
+	// TODO: add more here, after collecting data on the common
+	// error values see on Windows. (perhaps when running
+	// all.bat?)
+	return e
+}
+
+var (
+	modws2_32 = windows.NewLazySystemDLL("ws2_32.dll")
+
+	procbind        = modws2_32.NewProc("bind")
+	procgetpeername = modws2_32.NewProc("getpeername")
+	procgetsockname = modws2_32.NewProc("getsockname")
+)
+
+func bind(s windows.Handle, name unsafe.Pointer, namelen int32) (err error) {
+	r1, _, e1 := syscall.Syscall(procbind.Addr(), 3, uintptr(s), uintptr(name), uintptr(namelen))
+	if r1 == socketError {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func getpeername(s windows.Handle, name unsafe.Pointer, namelen *int32) (err error) {
+	r1, _, e1 := syscall.Syscall(procgetpeername.Addr(), 3, uintptr(s), uintptr(name), uintptr(unsafe.Pointer(namelen)))
+	if r1 == socketError {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func getsockname(s windows.Handle, name unsafe.Pointer, namelen *int32) (err error) {
+	r1, _, e1 := syscall.Syscall(procgetsockname.Addr(), 3, uintptr(s), uintptr(name), uintptr(unsafe.Pointer(namelen)))
+	if r1 == socketError {
+		err = errnoErr(e1)
+	}
+	return
+}