net: add multicast UDP support for plan9

The new implementation adds listening support on a multicast
address with plan9 network interfaces.

Fixes #17218

Change-Id: I2c75515e72e120acb71610cd077fddfbf9cf4e29
Reviewed-on: https://go-review.googlesource.com/29964
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/net/udpsock.go b/src/net/udpsock.go
index 246d644336b4291f6abdb341451a41a0dfddff2a..6a4aaf9e59cf123d16660bee0b3fb6b9adcb7a13 100644 (file)
--- a/src/net/udpsock.go
+++ b/src/net/udpsock.go
@@ -15,7 +15,7 @@ import (
 // BUG(mikio): On Windows, the File method of UDPConn is not
 // implemented.
 
-// BUG(mikio): On NaCl and Plan 9, the ListenMulticastUDP function is
+// BUG(mikio): On NaCl the ListenMulticastUDP function is
 // not implemented.
 
 // UDPAddr represents the address of a UDP end point.

diff --git a/src/net/udpsock_plan9.go b/src/net/udpsock_plan9.go
index 666f20622f611fe15688dd458c6c8244a9f6b188..1ce7f88c62c29fa9ecf7f97b69bfb54863868b51 100644 (file)
--- a/src/net/udpsock_plan9.go
+++ b/src/net/udpsock_plan9.go
@@ -109,5 +109,41 @@ func listenUDP(ctx context.Context, network string, laddr *UDPAddr) (*UDPConn, e
 }
 
 func listenMulticastUDP(ctx context.Context, network string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) {
-       return nil, syscall.EPLAN9
+       l, err := listenPlan9(ctx, network, gaddr)
+       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
+               }
+       }
+       for _, addr := range addrs {
+               if ipnet, ok := addr.(*IPNet); ok {
+                       _, err = l.ctl.WriteString("addmulti " + ipnet.IP.String() + " " + gaddr.IP.String())
+                       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()
+       if err != nil {
+               return nil, err
+       }
+       return newUDPConn(fd), nil
 }

diff --git a/src/net/udpsock_plan9_test.go b/src/net/udpsock_plan9_test.go
new file mode 100644 (file)
index 0000000..09f5a5d
--- /dev/null
+++ b/src/net/udpsock_plan9_test.go
@@ -0,0 +1,69 @@
+// Copyright 2016 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 (
+       "internal/testenv"
+       "runtime"
+       "testing"
+)
+
+func TestListenMulticastUDP(t *testing.T) {
+       testenv.MustHaveExternalNetwork(t)
+
+       ifcs, err := Interfaces()
+       if err != nil {
+               t.Skip(err.Error())
+       }
+       if len(ifcs) == 0 {
+               t.Skip("no network interfaces found")
+       }
+
+       var mifc *Interface
+       for _, ifc := range ifcs {
+               if ifc.Flags&FlagUp|FlagMulticast != FlagUp|FlagMulticast {
+                       continue
+               }
+               mifc = &ifc
+               break
+       }
+
+       if mifc == nil {
+               t.Skipf("no multicast interfaces found")
+       }
+
+       c1, err := ListenMulticastUDP("udp4", mifc, &UDPAddr{IP: ParseIP("224.0.0.254")})
+       if err != nil {
+               t.Fatalf("multicast not working on %s", runtime.GOOS)
+       }
+       c1addr := c1.LocalAddr().(*UDPAddr)
+       if err != nil {
+               t.Fatal(err)
+       }
+       defer c1.Close()
+
+       c2, err := ListenUDP("udp4", &UDPAddr{IP: IPv4zero, Port: 0})
+       c2addr := c2.LocalAddr().(*UDPAddr)
+       if err != nil {
+               t.Fatal(err)
+       }
+       defer c2.Close()
+
+       n, err := c2.WriteToUDP([]byte("data"), c1addr)
+       if err != nil {
+               t.Fatal(err)
+       }
+       if n != 4 {
+               t.Fatalf("got %d; want 4", n)
+       }
+
+       n, err = c1.WriteToUDP([]byte("data"), c2addr)
+       if err != nil {
+               t.Fatal(err)
+       }
+       if n != 4 {
+               t.Fatalf("got %d; want 4", n)
+       }
+}