net: udp, implement BindToDevice

R=rsc
CC=golang-dev, r
https://golang.org/cl/1271041

diff --git a/src/pkg/net/udpsock.go b/src/pkg/net/udpsock.go
index 6de69a9c9b2a2eb7a52d6c56c775e7d5065a157a..5e22c778d960fe3260f9a32dcf60cbcc83de8862 100644 (file)
--- a/src/pkg/net/udpsock.go
+++ b/src/pkg/net/udpsock.go
@@ -259,3 +259,13 @@ func ListenUDP(net string, laddr *UDPAddr) (c *UDPConn, err os.Error) {
        }
        return newUDPConn(fd), nil
 }
+
+// BindToDevice binds a UDPConn to a network interface.
+func (c *UDPConn) BindToDevice(device string) os.Error {
+       if !c.ok() {
+               return os.EINVAL
+       }
+       c.fd.incref()
+       defer c.fd.decref()
+       return os.NewSyscallError("setsockopt", syscall.BindToDevice(c.fd.sysfd, device))
+}