[Freeciv-Dev] Re: (PR#6707) Announce server on LAN

["Todd Goodman" <tsg@xxxxxxxxxxxxx>]

* Raimar Falke <i-freeciv-lists@xxxxxxxxxxxxx> [031105 15:41]:
> On Wed, Nov 05, 2003 at 11:05:19AM -0800, Todd Goodman wrote:
> > If supported, make the SIOCADDMULTI ioctl() call to add whatever
> > multicast group we want to use that isn't the all-hosts (224.0.0.1)
> > group.
> > 
> > Then set the TTL to the configured value (default and usually 1.)
> 
> > Note that if you have multiple interfaces you really need to do an
> > IP_MULTICAST_IF setsockopt() first to ensure it goes out the interface
> > you want...
> 
> Do I understand this correctly that freeciv would have to the above
> paragraph if multicast is used? Independent of what multicast group is
> used?

If there were multiple interfaces on the system, then it would be a good
thing to do.

I suspect most clients would have only one interface so it doesn't
matter.

> 
> If yes than I think that this is clearly too much. We can't touch the
> interfaces of a system. You would need root privileges anyway.

You misunderstand how that is done.  You'd add the IP_MULTICAST_IF
setsockopt() call before each multicast send to ensure it goes out the
interface you intend.  It's only for that socket so you're not messing
with the interfaces and I'm pretty sure you don't need root privileges
(unless you need them to send multicast in general.)

> 
> So what about the alternative plan to use broadcast? Seems simpler to
> me and will work with the case we discuss here (LAN). For the other
> case (finding servers on the internet) we have metaserver.

Most BSDs won't let you send to a broadcast address without root
privileges and I suspect the same is true of other implementations?

Why do you want to spam other stations on the LAN who don't care about
Freeciv?

It's not a problem for a home LAN of course, but if someone runs Freeciv
on a university or company LAN I can guarantee that there are admins who
will notice.

Do you want Freeciv to be known as an ill-behaved application?

Todd

> 
>       Raimar
> 
> -- 
>  email: rf13@xxxxxxxxxxxxxxxxx
>  "The very concept of PNP is a lovely dream that simply does not translate to
>   reality. The confusion of manually doing stuff is nothing compared to the
>   confusion of computers trying to do stuff and getting it wrong, which they
>   gleefully do with great enthusiasm." 
>     -- Jinx Tigr in the SDM