1 files changed, 153 insertions, 0 deletions
diff --git a/src/net/udpsock_plan9.go b/src/net/udpsock_plan9.go
new file mode 100644
index 0000000..79986ce
--- /dev/null
+++ b/src/net/udpsock_plan9.go
@@ -0,0 +1,153 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package net
+
+import (
+	"context"
+	"errors"
+	"os"
+	"syscall"
+)
+
+func (c *UDPConn) readFrom(b []byte) (n int, addr *UDPAddr, err error) {
+	buf := make([]byte, udpHeaderSize+len(b))
+	m, err := c.fd.Read(buf)
+	if err != nil {
+		return 0, nil, err
+	}
+	if m < udpHeaderSize {
+		return 0, nil, errors.New("short read reading UDP header")
+	}
+	buf = buf[:m]
+
+	h, buf := unmarshalUDPHeader(buf)
+	n = copy(b, buf)
+	return n, &UDPAddr{IP: h.raddr, Port: int(h.rport)}, nil
+}
+
+func (c *UDPConn) readMsg(b, oob []byte) (n, oobn, flags int, addr *UDPAddr, err error) {
+	return 0, 0, 0, nil, syscall.EPLAN9
+}
+
+func (c *UDPConn) writeTo(b []byte, addr *UDPAddr) (int, error) {
+	if addr == nil {
+		return 0, errMissingAddress
+	}
+	h := new(udpHeader)
+	h.raddr = addr.IP.To16()
+	h.laddr = c.fd.laddr.(*UDPAddr).IP.To16()
+	h.ifcaddr = IPv6zero // ignored (receive only)
+	h.rport = uint16(addr.Port)
+	h.lport = uint16(c.fd.laddr.(*UDPAddr).Port)
+
+	buf := make([]byte, udpHeaderSize+len(b))
+	i := copy(buf, h.Bytes())
+	copy(buf[i:], b)
+	if _, err := c.fd.Write(buf); err != nil {
+		return 0, err
+	}
+	return len(b), nil
+}
+
+func (c *UDPConn) writeMsg(b, oob []byte, addr *UDPAddr) (n, oobn int, err error) {
+	return 0, 0, syscall.EPLAN9
+}
+
+func (sd *sysDialer) dialUDP(ctx context.Context, laddr, raddr *UDPAddr) (*UDPConn, error) {
+	fd, err := dialPlan9(ctx, sd.network, laddr, raddr)
+	if err != nil {
+		return nil, err
+	}
+	return newUDPConn(fd), nil
+}
+
+const udpHeaderSize = 16*3 + 2*2
+
+type udpHeader struct {
+	raddr, laddr, ifcaddr IP
+	rport, lport          uint16
+}
+
+func (h *udpHeader) Bytes() []byte {
+	b := make([]byte, udpHeaderSize)
+	i := 0
+	i += copy(b[i:i+16], h.raddr)
+	i += copy(b[i:i+16], h.laddr)
+	i += copy(b[i:i+16], h.ifcaddr)
+	b[i], b[i+1], i = byte(h.rport>>8), byte(h.rport), i+2
+	b[i], b[i+1], i = byte(h.lport>>8), byte(h.lport), i+2
+	return b
+}
+
+func unmarshalUDPHeader(b []byte) (*udpHeader, []byte) {
+	h := new(udpHeader)
+	h.raddr, b = IP(b[:16]), b[16:]
+	h.laddr, b = IP(b[:16]), b[16:]
+	h.ifcaddr, b = IP(b[:16]), b[16:]
+	h.rport, b = uint16(b[0])<<8|uint16(b[1]), b[2:]
+	h.lport, b = uint16(b[0])<<8|uint16(b[1]), b[2:]
+	return h, b
+}
+
+func (sl *sysListener) listenUDP(ctx context.Context, laddr *UDPAddr) (*UDPConn, error) {
+	l, err := listenPlan9(ctx, sl.network, laddr)
+	if err != nil {
+		return nil, err
+	}
+	_, err = l.ctl.WriteString("headers")
+	if err != nil {
+		return nil, err
+	}
+	l.data, err = os.OpenFile(l.dir+"/data", os.O_RDWR, 0)
+	if err != nil {
+		return nil, err
+	}
+	fd, err := l.netFD()
+	return newUDPConn(fd), err
+}
+
+func (sl *sysListener) listenMulticastUDP(ctx context.Context, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) {
+	// Plan 9 does not like announce command with a multicast address,
+	// so do not specify an IP address when listening.
+	l, err := listenPlan9(ctx, sl.network, &UDPAddr{IP: nil, Port: gaddr.Port, Zone: gaddr.Zone})
+	if err != nil {
+		return nil, err
+	}
+	_, err = l.ctl.WriteString("headers")
+	if err != nil {
+		return nil, err
+	}
+	var addrs []Addr
+	if ifi != nil {
+		addrs, err = ifi.Addrs()
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		addrs, err = InterfaceAddrs()
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	have4 := gaddr.IP.To4() != nil
+	for _, addr := range addrs {
+		if ipnet, ok := addr.(*IPNet); ok && (ipnet.IP.To4() != nil) == have4 {
+			_, err = l.ctl.WriteString("addmulti " + ipnet.IP.String() + " " + gaddr.IP.String())
+			if err != nil {
+				return nil, &OpError{Op: "addmulti", Net: "", Source: nil, Addr: ipnet, Err: err}
+			}
+		}
+	}
+	l.data, err = os.OpenFile(l.dir+"/data", os.O_RDWR, 0)
+	if err != nil {
+		return nil, err
+	}
+	fd, err := l.netFD()
+	if err != nil {
+		return nil, err
+	}
+	return newUDPConn(fd), nil
+}