func benchmarkReadWriteIPv4UDP(b *testing.B, p *ipv4.PacketConn, wb, rb []byte, dst net.Addr, ifi *net.Interface) {
cm := ipv4.ControlMessage{TTL: 1}
if ifi != nil {
cm.IfIndex = ifi.Index
}
if n, err := p.WriteTo(wb, &cm, dst); err != nil {
b.Fatal(err)
} else if n != len(wb) {
b.Fatalf("got %v; want %v", n, len(wb))
}
if _, _, _, err := p.ReadFrom(rb); err != nil {
b.Fatal(err)
}
}
func sender(p *ipv4.PacketConn, dst net.Addr) {
ift, err := net.Interfaces()
if err != nil {
log.Fatal(err)
}
for i := 0; ; i++ {
avail := net.FlagMulticast | net.FlagUp
for _, ifi := range ift {
if ifi.Flags&avail != avail {
continue
}
p.SetMulticastInterface(&ifi)
b := []byte(fmt.Sprintf("#%v HELLLO-R-U-THERE", i))
if _, err := p.WriteTo(b, nil, dst); err != nil {
log.Println(err, "on", ifi)
continue
}
log.Printf("%v bytes sent to %v via %v\n", len(b), dst, ifi)
time.Sleep(time.Second)
}
}
}