70 lines
1.4 KiB
Go
70 lines
1.4 KiB
Go
// Copyright (C) 2014 Jakob Borg and Contributors (see the CONTRIBUTORS file).
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// All rights reserved. Use of this source code is governed by an MIT-style
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// license that can be found in the LICENSE file.
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package beacon
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import "net"
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type Multicast struct {
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conn *net.UDPConn
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addr *net.UDPAddr
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inbox chan []byte
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outbox chan recv
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}
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func NewMulticast(addr string) (*Multicast, error) {
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gaddr, err := net.ResolveUDPAddr("udp", addr)
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if err != nil {
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return nil, err
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}
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conn, err := net.ListenMulticastUDP("udp", nil, gaddr)
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if err != nil {
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return nil, err
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}
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b := &Multicast{
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conn: conn,
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addr: gaddr,
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inbox: make(chan []byte),
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outbox: make(chan recv, 16),
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}
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go genericReader(b.conn, b.outbox)
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go b.writer()
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return b, nil
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}
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func (b *Multicast) Send(data []byte) {
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b.inbox <- data
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}
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func (b *Multicast) Recv() ([]byte, net.Addr) {
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recv := <-b.outbox
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return recv.data, recv.src
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}
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func (b *Multicast) writer() {
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for bs := range b.inbox {
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intfs, err := net.Interfaces()
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if err != nil {
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l.Warnln("multicast interfaces:", err)
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continue
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}
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for _, intf := range intfs {
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if intf.Flags&net.FlagUp != 0 && intf.Flags&net.FlagMulticast != 0 {
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addr := *b.addr
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addr.Zone = intf.Name
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_, err = b.conn.WriteTo(bs, &addr)
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if err != nil {
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if debug {
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l.Debugln(err, "on write to", addr)
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}
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} else if debug {
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l.Debugf("sent %d bytes to %s", len(bs), addr.String())
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}
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}
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}
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}
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}
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