[interfaces] darwin (#423)

2 files changed, 22 insertions, 2 deletions

diff --git a/interfaces/bindtodevice_bsd.go b/interfaces/bindtodevice_bsd.go
index 50e21c6..226e2a8 100644
--- a/interfaces/bindtodevice_bsd.go
+++ b/interfaces/bindtodevice_bsd.go
@@ -1,10 +1,11 @@
-// +build aix freebsd openbsd netbsd darwin
+// +build aix freebsd openbsd netbsd
 
 package interfaces
 
 import (
 	"net"
-	"syscall"
+
+	"golang.org/x/sys/unix"
 )
 
 // BindToInterface emulates linux's SO_BINDTODEVICE option for a socket by using
diff --git a/interfaces/bindtodevice_darwin.go b/interfaces/bindtodevice_darwin.go
new file mode 100644
index 0000000..5ddfc0e
--- /dev/null
+++ b/interfaces/bindtodevice_darwin.go
@@ -0,0 +1,19 @@
+// +build darwin
+
+package interfaces
+
+import (
+	"net"
+
+	"golang.org/x/sys/unix"
+)
+
+// BindToInterface emulates linux's SO_BINDTODEVICE option for a socket by using
+// IP_BOUND_IF.
+func BindToInterface(fd int, ifname string) error {
+	iface, err := net.InterfaceByName(ifname)
+	if err != nil {
+		return err
+	}
+	return unix.SetsockoptInt(fd, unix.IPPROTO_IP, unix.IP_BOUND_IF, iface.Index)
+}