func ipv4MulticastInterface(fd int) (*net.Interface, error) {
mreqn, err := syscall.GetsockoptIPMreqn(fd, syscall.IPPROTO_IP, syscall.IP_MULTICAST_IF)
if err != nil {
return nil, os.NewSyscallError("getsockopt", err)
}
if int(mreqn.Ifindex) == 0 {
return nil, nil
}
return net.InterfaceByIndex(int(mreqn.Ifindex))
}
func ipv4MulticastInterface(fd int) (*net.Interface, error) {
mreqn, err := syscall.GetsockoptIPMreqn(fd, ianaProtocolIP, sysSockoptMulticastInterface)
if err != nil {
return nil, os.NewSyscallError("getsockopt", err)
}
if mreqn.Ifindex == 0 {
return nil, nil
}
return net.InterfaceByIndex(int(mreqn.Ifindex))
}
func ipv4MulticastInterface(fd *netFD) (*Interface, error) {
fd.incref()
defer fd.decref()
mreq, err := syscall.GetsockoptIPMreqn(fd.sysfd, syscall.IPPROTO_IP, syscall.IP_MULTICAST_IF)
if err != nil {
return nil, os.NewSyscallError("getsockopt", err)
}
if int(mreq.Ifindex) == 0 {
return nil, nil
}
return InterfaceByIndex(int(mreq.Ifindex))
}