/
socket.go
153 lines (129 loc) · 4.86 KB
/
socket.go
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//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
}