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

["Raimar Falke" <i-freeciv-lists@xxxxxxxxxxxxx>]

On Wed, Nov 05, 2003 at 12:47:43PM -0800, Todd Goodman wrote:
> * 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.

How should freeciv decide this?

> 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?

Uhh I think you are correct here. So the plan with the broadcast looks
rather dead.

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

1 byte UDP packets at each client startup isn't spamming in my
eyes. People waste much more bandwidth polling their pop3 accounts.

> 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.

It will only send you these ping packets if the user selects the LAN
notebook.

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

I want a small solution which is portable. And if there are deficits
with the feature it would be nice if we can give the user some
feedback.

        Raimar

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