81 lines
1.9 KiB
Go
81 lines
1.9 KiB
Go
// Copyright (C) 2014 The Syncthing Authors.
|
|
//
|
|
// This program is free software: you can redistribute it and/or modify it
|
|
// under the terms of the GNU General Public License as published by the Free
|
|
// Software Foundation, either version 3 of the License, or (at your option)
|
|
// any later version.
|
|
//
|
|
// This program is distributed in the hope that it will be useful, but WITHOUT
|
|
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
|
|
// more details.
|
|
//
|
|
// You should have received a copy of the GNU General Public License along
|
|
// with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
package beacon
|
|
|
|
import "net"
|
|
|
|
type Multicast struct {
|
|
conn *net.UDPConn
|
|
addr *net.UDPAddr
|
|
inbox chan []byte
|
|
outbox chan recv
|
|
}
|
|
|
|
func NewMulticast(addr string) (*Multicast, error) {
|
|
gaddr, err := net.ResolveUDPAddr("udp", addr)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
conn, err := net.ListenMulticastUDP("udp", nil, gaddr)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
b := &Multicast{
|
|
conn: conn,
|
|
addr: gaddr,
|
|
inbox: make(chan []byte),
|
|
outbox: make(chan recv, 16),
|
|
}
|
|
|
|
go genericReader(b.conn, b.outbox)
|
|
go b.writer()
|
|
|
|
return b, nil
|
|
}
|
|
|
|
func (b *Multicast) Send(data []byte) {
|
|
b.inbox <- data
|
|
}
|
|
|
|
func (b *Multicast) Recv() ([]byte, net.Addr) {
|
|
recv := <-b.outbox
|
|
return recv.data, recv.src
|
|
}
|
|
|
|
func (b *Multicast) writer() {
|
|
for bs := range b.inbox {
|
|
intfs, err := net.Interfaces()
|
|
if err != nil {
|
|
l.Warnln("multicast interfaces:", err)
|
|
continue
|
|
}
|
|
for _, intf := range intfs {
|
|
if intf.Flags&net.FlagUp != 0 && intf.Flags&net.FlagMulticast != 0 {
|
|
addr := *b.addr
|
|
addr.Zone = intf.Name
|
|
_, err = b.conn.WriteTo(bs, &addr)
|
|
if err != nil {
|
|
if debug {
|
|
l.Debugln(err, "on write to", addr)
|
|
}
|
|
} else if debug {
|
|
l.Debugf("sent %d bytes to %s", len(bs), addr.String())
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|