diff --git a/src/pkg/net/udpsock_plan9.go b/src/pkg/net/udpsock_plan9.go
index 5ac0b4d..aaa7e5b 100644
--- a/src/pkg/net/udpsock_plan9.go
+++ b/src/pkg/net/udpsock_plan9.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// UDP for Plan 9
+// UDP sockets for Plan 9
 
 package net
 
@@ -24,8 +24,9 @@
 // It returns the number of bytes copied into b and the return address
 // that was on the packet.
 //
-// ReadFromUDP can be made to time out and return an error with Timeout() == true
-// after a fixed time limit; see SetDeadline and SetReadDeadline.
+// ReadFromUDP can be made to time out and return an error with
+// Timeout() == true after a fixed time limit; see SetDeadline and
+// SetReadDeadline.
 func (c *UDPConn) ReadFromUDP(b []byte) (n int, addr *UDPAddr, err error) {
 	if !c.ok() {
 		return 0, nil, syscall.EINVAL
@@ -59,12 +60,22 @@
 	return c.ReadFromUDP(b)
 }
 
-// WriteToUDP writes a UDP packet to addr via c, copying the payload from b.
+// ReadMsgUDP reads a packet from c, copying the payload into b and
+// the associdated out-of-band data into oob.  It returns the number
+// of bytes copied into b, the number of bytes copied into oob, the
+// flags that were set on the packet and the source address of the
+// packet.
+func (c *UDPConn) ReadMsgUDP(b, oob []byte) (n, oobn, flags int, addr *UDPAddr, err error) {
+	return 0, 0, 0, nil, syscall.EPLAN9
+}
+
+// WriteToUDP writes a UDP packet to addr via c, copying the payload
+// from b.
 //
-// WriteToUDP can be made to time out and return
-// an error with Timeout() == true after a fixed time limit;
-// see SetDeadline and SetWriteDeadline.
-// On packet-oriented connections, write timeouts are rare.
+// WriteToUDP can be made to time out and return an error with
+// Timeout() == true after a fixed time limit; see SetDeadline and
+// SetWriteDeadline.  On packet-oriented connections, write timeouts
+// are rare.
 func (c *UDPConn) WriteToUDP(b []byte, addr *UDPAddr) (n int, err error) {
 	if !c.ok() {
 		return 0, syscall.EINVAL
@@ -100,9 +111,16 @@
 	return c.WriteToUDP(b, a)
 }
 
+// WriteMsgUDP writes a packet to addr via c, copying the payload from
+// b and the associated out-of-band data from oob.  It returns the
+// number of payload and out-of-band bytes written.
+func (c *UDPConn) WriteMsgUDP(b, oob []byte, addr *UDPAddr) (n, oobn int, err error) {
+	return 0, 0, syscall.EPLAN9
+}
+
 // DialUDP connects to the remote address raddr on the network net,
-// which must be "udp", "udp4", or "udp6".  If laddr is not nil, it is used
-// as the local address for the connection.
+// which must be "udp", "udp4", or "udp6".  If laddr is not nil, it is
+// used as the local address for the connection.
 func DialUDP(net string, laddr, raddr *UDPAddr) (c *UDPConn, err error) {
 	switch net {
 	case "udp", "udp4", "udp6":
@@ -147,10 +165,10 @@
 	return h, b
 }
 
-// ListenUDP listens for incoming UDP packets addressed to the
-// local address laddr.  The returned connection c's ReadFrom
-// and WriteTo methods can be used to receive and send UDP
-// packets with per-packet addressing.
+// ListenUDP listens for incoming UDP packets addressed to the local
+// address laddr.  The returned connection c's ReadFrom and WriteTo
+// methods can be used to receive and send UDP packets with per-packet
+// addressing.
 func ListenUDP(net string, laddr *UDPAddr) (c *UDPConn, err error) {
 	switch net {
 	case "udp", "udp4", "udp6":
@@ -172,9 +190,9 @@
 }
 
 // ListenMulticastUDP listens for incoming multicast UDP packets
-// addressed to the group address gaddr on ifi, which specifies
-// the interface to join.  ListenMulticastUDP uses default
-// multicast interface if ifi is nil.
+// addressed to the group address gaddr on ifi, which specifies the
+// interface to join.  ListenMulticastUDP uses default multicast
+// interface if ifi is nil.
 func ListenMulticastUDP(net string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) {
 	return nil, syscall.EPLAN9
 }