boundif: introduce API for socket binding

8 files changed, 155 insertions, 21 deletions

diff --git a/device/boundif_android.go b/device/boundif_android.go
new file mode 100644
index 0000000..ecc9331
--- /dev/null
+++ b/device/boundif_android.go
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+func (device *Device) PeekLookAtSocketFd4() (fd int, err error) {
+	sysconn, err := device.net.bind.(*nativeBind).ipv4.SyscallConn()
+	if err != nil {
+		return
+	}
+	err = sysconn.Control(func(f uintptr) {
+		fd = int(f)
+	})
+	if err != nil {
+		return
+	}
+	return
+}
+
+func (device *Device) PeekLookAtSocketFd6() (fd int, err error) {
+	sysconn, err := device.net.bind.(*nativeBind).ipv6.SyscallConn()
+	if err != nil {
+		return
+	}
+	err = sysconn.Control(func(f uintptr) {
+		fd = int(f)
+	})
+	if err != nil {
+		return
+	}
+	return
+}
diff --git a/device/boundif_darwin.go b/device/boundif_darwin.go
new file mode 100644
index 0000000..b3d10ba
--- /dev/null
+++ b/device/boundif_darwin.go
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"golang.org/x/sys/unix"
+)
+
+func (device *Device) BindSocketToInterface4(interfaceIndex uint32) error {
+	sysconn, err := device.net.bind.(*nativeBind).ipv4.SyscallConn()
+	if err != nil {
+		return nil
+	}
+	err2 := sysconn.Control(func(fd uintptr) {
+		err = unix.SetsockoptInt(int(fd), unix.IPPROTO_IP, unix.IP_BOUND_IF, int(interfaceIndex))
+	})
+	if err2 != nil {
+		return err2
+	}
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (device *Device) BindSocketToInterface6(interfaceIndex uint32) error {
+	sysconn, err := device.net.bind.(*nativeBind).ipv4.SyscallConn()
+	if err != nil {
+		return nil
+	}
+	err2 := sysconn.Control(func(fd uintptr) {
+		err = unix.SetsockoptInt(int(fd), unix.IPPROTO_IPV6, unix.IPV6_BOUND_IF, int(interfaceIndex))
+	})
+	if err2 != nil {
+		return err2
+	}
+	if err != nil {
+		return err
+	}
+	return nil
+}
\ No newline at end of file
diff --git a/device/boundif_windows.go b/device/boundif_windows.go
new file mode 100644
index 0000000..00631cb
--- /dev/null
+++ b/device/boundif_windows.go
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"encoding/binary"
+	"golang.org/x/sys/windows"
+	"unsafe"
+)
+
+const (
+	sockoptIP_UNICAST_IF   = 31
+	sockoptIPV6_UNICAST_IF = 31
+)
+
+func (device *Device) BindSocketToInterface4(interfaceIndex uint32) error {
+	/* MSDN says for IPv4 this needs to be in net byte order, so that it's like an IP address with leading zeros. */
+	bytes := make([]byte, 4)
+	binary.BigEndian.PutUint32(bytes, interfaceIndex)
+	interfaceIndex = *(*uint32)(unsafe.Pointer(&bytes[0]))
+
+	sysconn, err := device.net.bind.(*nativeBind).ipv4.SyscallConn()
+	if err != nil {
+		return err
+	}
+	err2 := sysconn.Control(func(fd uintptr) {
+		err = windows.SetsockoptInt(windows.Handle(fd), windows.IPPROTO_IP, sockoptIP_UNICAST_IF, int(interfaceIndex))
+	})
+	if err2 != nil {
+		return err2
+	}
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (device *Device) BindSocketToInterface6(interfaceIndex uint32) error {
+	sysconn, err := device.net.bind.(*nativeBind).ipv6.SyscallConn()
+	if err != nil {
+		return err
+	}
+	err2 := sysconn.Control(func(fd uintptr) {
+		err = windows.SetsockoptInt(windows.Handle(fd), windows.IPPROTO_IPV6, sockoptIPV6_UNICAST_IF, int(interfaceIndex))
+	})
+	if err2 != nil {
+		return err2
+	}
+	if err != nil {
+		return err
+	}
+	return nil
+}
\ No newline at end of file
diff --git a/device/conn_default.go b/device/conn_default.go
index 8a86719..820bb96 100644
--- a/device/conn_default.go
+++ b/device/conn_default.go
@@ -20,14 +20,14 @@ import (
  * See conn_linux.go for an implementation on the linux platform.
  */
 
-type NativeBind struct {
+type nativeBind struct {
 	ipv4 *net.UDPConn
 	ipv6 *net.UDPConn
 }
 
 type NativeEndpoint net.UDPAddr
 
-var _ Bind = (*NativeBind)(nil)
+var _ Bind = (*nativeBind)(nil)
 var _ Endpoint = (*NativeEndpoint)(nil)
 
 func CreateEndpoint(s string) (Endpoint, error) {
@@ -100,7 +100,7 @@ func extractErrno(err error) error {
 
 func CreateBind(uport uint16, device *Device) (Bind, uint16, error) {
 	var err error
-	var bind NativeBind
+	var bind nativeBind
 
 	port := int(uport)
 
@@ -119,7 +119,7 @@ func CreateBind(uport uint16, device *Device) (Bind, uint16, error) {
 	return &bind, uint16(port), nil
 }
 
-func (bind *NativeBind) Close() error {
+func (bind *nativeBind) Close() error {
 	var err1, err2 error
 	if bind.ipv4 != nil {
 		err1 = bind.ipv4.Close()
@@ -133,7 +133,7 @@ func (bind *NativeBind) Close() error {
 	return err2
 }
 
-func (bind *NativeBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
+func (bind *nativeBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
 	if bind.ipv4 == nil {
 		return 0, nil, syscall.EAFNOSUPPORT
 	}
@@ -144,7 +144,7 @@ func (bind *NativeBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
 	return n, (*NativeEndpoint)(endpoint), err
 }
 
-func (bind *NativeBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
+func (bind *nativeBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
 	if bind.ipv6 == nil {
 		return 0, nil, syscall.EAFNOSUPPORT
 	}
@@ -152,7 +152,7 @@ func (bind *NativeBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
 	return n, (*NativeEndpoint)(endpoint), err
 }
 
-func (bind *NativeBind) Send(buff []byte, endpoint Endpoint) error {
+func (bind *nativeBind) Send(buff []byte, endpoint Endpoint) error {
 	var err error
 	nend := endpoint.(*NativeEndpoint)
 	if nend.IP.To4() != nil {
diff --git a/device/conn_linux.go b/device/conn_linux.go
index 49949d5..6a8520e 100644
--- a/device/conn_linux.go
+++ b/device/conn_linux.go
@@ -63,7 +63,7 @@ func (endpoint *NativeEndpoint) dst6() *unix.SockaddrInet6 {
 	return (*unix.SockaddrInet6)(unsafe.Pointer(&endpoint.dst[0]))
 }
 
-type NativeBind struct {
+type nativeBind struct {
 	sock4         int
 	sock6         int
 	netlinkSock   int
@@ -72,7 +72,7 @@ type NativeBind struct {
 }
 
 var _ Endpoint = (*NativeEndpoint)(nil)
-var _ Bind = (*NativeBind)(nil)
+var _ Bind = (*nativeBind)(nil)
 
 func CreateEndpoint(s string) (Endpoint, error) {
 	var end NativeEndpoint
@@ -127,9 +127,9 @@ func createNetlinkRouteSocket() (int, error) {
 
 }
 
-func CreateBind(port uint16, device *Device) (*NativeBind, uint16, error) {
+func CreateBind(port uint16, device *Device) (*nativeBind, uint16, error) {
 	var err error
-	var bind NativeBind
+	var bind nativeBind
 	var newPort uint16
 
 	bind.netlinkSock, err = createNetlinkRouteSocket()
@@ -176,7 +176,7 @@ func CreateBind(port uint16, device *Device) (*NativeBind, uint16, error) {
 	return &bind, port, nil
 }
 
-func (bind *NativeBind) SetMark(value uint32) error {
+func (bind *nativeBind) SetMark(value uint32) error {
 	if bind.sock6 != -1 {
 		err := unix.SetsockoptInt(
 			bind.sock6,
@@ -213,7 +213,7 @@ func closeUnblock(fd int) error {
 	return unix.Close(fd)
 }
 
-func (bind *NativeBind) Close() error {
+func (bind *nativeBind) Close() error {
 	var err1, err2, err3 error
 	if bind.sock6 != -1 {
 		err1 = closeUnblock(bind.sock6)
@@ -232,7 +232,7 @@ func (bind *NativeBind) Close() error {
 	return err3
 }
 
-func (bind *NativeBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
+func (bind *nativeBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
 	var end NativeEndpoint
 	if bind.sock6 == -1 {
 		return 0, nil, syscall.EAFNOSUPPORT
@@ -245,7 +245,7 @@ func (bind *NativeBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
 	return n, &end, err
 }
 
-func (bind *NativeBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
+func (bind *nativeBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
 	var end NativeEndpoint
 	if bind.sock4 == -1 {
 		return 0, nil, syscall.EAFNOSUPPORT
@@ -258,7 +258,7 @@ func (bind *NativeBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
 	return n, &end, err
 }
 
-func (bind *NativeBind) Send(buff []byte, end Endpoint) error {
+func (bind *nativeBind) Send(buff []byte, end Endpoint) error {
 	nend := end.(*NativeEndpoint)
 	if !nend.isV6 {
 		if bind.sock4 == -1 {
@@ -592,7 +592,7 @@ func receive6(sock int, buff []byte, end *NativeEndpoint) (int, error) {
 	return size, nil
 }
 
-func (bind *NativeBind) routineRouteListener(device *Device) {
+func (bind *nativeBind) routineRouteListener(device *Device) {
 	type peerEndpointPtr struct {
 		peer     *Peer
 		endpoint *Endpoint
diff --git a/device/mark_default.go b/device/mark_default.go
index 76b1015..7de2524 100644
--- a/device/mark_default.go
+++ b/device/mark_default.go
@@ -7,6 +7,6 @@
 
 package device
 
-func (bind *NativeBind) SetMark(mark uint32) error {
+func (bind *nativeBind) SetMark(mark uint32) error {
 	return nil
 }
diff --git a/device/mark_unix.go b/device/mark_unix.go
index ee64cc9..a791c71 100644
--- a/device/mark_unix.go
+++ b/device/mark_unix.go
@@ -25,7 +25,7 @@ func init() {
 	}
 }
 
-func (bind *NativeBind) SetMark(mark uint32) error {
+func (bind *nativeBind) SetMark(mark uint32) error {
 	var operr error
 	if fwmarkIoctl == 0 {
 		return nil
diff --git a/device/peer.go b/device/peer.go
index af3ef9d..815dff4 100644
--- a/device/peer.go
+++ b/device/peer.go
@@ -258,10 +258,10 @@ func (peer *Peer) Stop() {
 	peer.ZeroAndFlushAll()
 }
 
-var roamingDisabled bool
+var RoamingDisabled bool
 
 func (peer *Peer) SetEndpointFromPacket(endpoint Endpoint) {
-	if roamingDisabled {
+	if RoamingDisabled {
 		return
 	}
 	peer.Lock()