/
sockets.go
174 lines (150 loc) · 5.07 KB
/
sockets.go
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//go:build windows
package sockets
import (
"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 sockets.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 ErrSocketClosed = fmt.Errorf("socket closed: %w", net.ErrClosed)
// CloseWriter is a connection that can disable writing to itself.
type CloseWriter interface {
net.Conn
CloseWrite() error
}
// CloseReader is a connection that can disable reading from itself.
type CloseReader interface {
net.Conn
CloseRead() error
}
// GetSockName returns the socket's local address. It will call the `rsa.FromBytes()` on the
// buffer returned by the getsockname syscall. The buffer is allocated to the size specified
// by `rsa.Sockaddr()`.
func GetSockName(s windows.Handle, rsa RawSockaddr) error {
ptr, l, err := rsa.Sockaddr()
if err != nil {
return fmt.Errorf("could not find socket size to allocate buffer: %w", err)
}
if err = validateSockAddr(ptr, l); err != nil {
return err
}
b := make([]byte, l)
err = getsockname(s, unsafe.Pointer(&b[0]), &l)
if err != nil {
// 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 err
}
return rsa.FromBytes(b[: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 find socket size to allocate buffer: %w", err)
}
if err = validateSockAddr(ptr, l); err != nil {
return err
}
b := make([]byte, l)
err = getpeername(s, unsafe.Pointer(&b[0]), &l)
if err != nil {
return err
}
return rsa.FromBytes(b[:l])
}
func Bind(s windows.Handle, rsa RawSockaddr) (err error) {
ptr, l, err := rsa.Sockaddr()
if err != nil {
return fmt.Errorf("could not find socket pointer and size: %w", err)
}
if err = validateSockAddr(ptr, l); err != nil {
return 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)
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{
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) {
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
}