Files
nebula/udp/udp_windows.go
2026-05-05 17:05:50 -05:00

73 lines
2.2 KiB
Go

//go:build !e2e_testing
// +build !e2e_testing
package udp
import (
"fmt"
"log/slog"
"net"
"net/netip"
"syscall"
"golang.org/x/sys/windows"
)
func NewListener(l *slog.Logger, ip netip.Addr, port int, multi bool, batch int) (Conn, error) {
if multi {
//NOTE: Technically we can support it with RIO but it wouldn't be at the socket level
// The udp stack would need to be reworked to hide away the implementation differences between
// Windows and Linux
return nil, fmt.Errorf("multiple udp listeners not supported on windows")
}
rc, err := NewRIOListener(l, ip, port)
if err == nil {
return rc, nil
}
l.Error("Falling back to standard udp sockets", "error", err)
return NewGenericListener(l, ip, port, multi, batch)
}
func NewListenConfig(multi bool) net.ListenConfig {
return net.ListenConfig{
Control: func(network, address string, c syscall.RawConn) error {
if multi {
// There is no way to support multiple listeners safely on Windows:
// https://docs.microsoft.com/en-us/windows/desktop/winsock/using-so-reuseaddr-and-so-exclusiveaddruse
return fmt.Errorf("multiple udp listeners not supported on windows")
}
return nil
},
}
}
func (u *GenericConn) Rebind() error {
return nil
}
// Windows IP_DONTFRAGMENT and IPV6_DONTFRAG are not exposed in the
// golang.org/x/sys/windows package. Defined locally per the values in
// ws2ipdef.h / ws2tcpip.h. These are stable Win32 constants that have not
// changed since at least Windows Vista.
const (
winIPDontFragment = 14
winIPv6DontFrag = 14
)
// EnablePathMTUDiscovery sets the don't-fragment bit on outbound packets.
// Windows uses IP_DONTFRAGMENT (v4) and IPV6_DONTFRAG (v6) at IPPROTO_IP /
// IPPROTO_IPV6 respectively. Note: this only enables DF on the GenericConn
// fallback path. The RIO path (RIOConn) has its own EnablePathMTUDiscovery
// in udp_rio_windows.go and is currently a no-op pending RIO-specific work.
func (u *GenericConn) EnablePathMTUDiscovery() error {
v4 := u.isV4Socket()
return u.controlFD(func(fd uintptr) error {
if v4 {
return windows.SetsockoptInt(windows.Handle(fd), windows.IPPROTO_IP, winIPDontFragment, 1)
}
return windows.SetsockoptInt(windows.Handle(fd), windows.IPPROTO_IPV6, winIPv6DontFrag, 1)
})
}