underlay: support SockOptInt on all platforms incl Windows

private/underlay/sockctrl/sockctrl.go

@@ -12,11 +12,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build go1.9
-// +build go1.9
+// In Windows, SetSockOptInt and GetSockOptInt require syscall.Handle instead of int.
+//go:build !windows
+// +build !windows
 
-// This version of sockctrl is for Go versions >= 1.9, where the socket FDs are
-// accessible via RawConn.Control().
 package sockctrl
 
 import (

private/underlay/sockctrl/sockctrl_windows.go

@@ -0,0 +1,44 @@
+// Copyright 2017 ETH Zurich
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// In Windows, SetSockOptInt and GetSockOptInt require syscall.Handle instead of int.
+//go:build windows
+// +build windows
+
+package sockctrl
+
+import (
+	"net"
+	"syscall"
+
+	"github.com/scionproto/scion/pkg/private/serrors"
+)
+
+func SockControl(c *net.UDPConn, f func(syscall.Handle) error) error {
+	rawConn, err := c.SyscallConn()
+	if err != nil {
+		return serrors.Wrap("sockctrl: error accessing raw connection", err)
+	}
+	var ctrlErr error
+	err = rawConn.Control(func(fd uintptr) {
+		ctrlErr = f(syscall.Handle(fd))
+	})
+	if err != nil {
+		return serrors.Wrap("sockctrl: RawConn.Control error", err)
+	}
+	if ctrlErr != nil {
+		return serrors.Wrap("sockctrl: control function error", ctrlErr)
+	}
+	return nil
+}

private/underlay/sockctrl/sockopt.go

@@ -12,6 +12,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// In Windows, SetSockOptInt and GetSockOptInt require syscall.Handle instead of int.
+//go:build !windows
+// +build !windows
+
 package sockctrl
 
 import (

private/underlay/sockctrl/sockopt_windows.go

@@ -0,0 +1,40 @@
+// Copyright 2017 ETH Zurich
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// In Windows, SetSockOptInt and GetSockOptInt require syscall.Handle instead of int.
+//go:build windows
+// +build windows
+
+package sockctrl
+
+import (
+	"net"
+	"syscall"
+)
+
+func GetsockoptInt(c *net.UDPConn, level, opt int) (int, error) {
+	var val int
+	err := SockControl(c, func(fd syscall.Handle) error {
+		var err error
+		val, err = syscall.GetsockoptInt(fd, level, opt)
+		return err
+	})
+	return val, err
+}
+
+func SetsockoptInt(c *net.UDPConn, level, opt, value int) error {
+	return SockControl(c, func(fd syscall.Handle) error {
+		return syscall.SetsockoptInt(fd, level, opt, value)
+	})
+}