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

["Petrus Viljoen" <pviljoen@xxxxxxxxxx>]

>On Wed, Nov 05, 2003 at 06:02:02AM -0800, Todd Goodman wrote:
>> * Raimar Falke <i-freeciv-lists@xxxxxxxxxxxxx> [031105 07:04]:
>> > On Mon, Nov 03, 2003 at 11:05:37AM -0800, Todd Goodman wrote:
>> > > * Raimar Falke <i-freeciv-lists@xxxxxxxxxxxxx> [031103 11:30]:
>> > > > In addition the URL states:
.....
>> But it isn't broadcast.
>> 
>> The whole point of multicast is to send to a subset of addresses on the
>> Ethernet without resorting to broadcasting.
>> 
>> The all hosts address is mainly so that routers can send packets that all
>> hosts would like to receive (supposedly all hosts would want to receive
>> an indication that they can send traffic off the local network via that
>> router.)

>I want to minimize the requirements for freeciv. This means that it is
>bad that a user have to run a special program before he can play
>freeciv or that the user has to install extra software or (the worst)
>have to recompile his kernel/OS.

>Also portabiltiy is important. Searching for SIOCADDMULTI and "win32"
>or "winsock" didn't reveal
>anything. 
>http://msdn.microsoft.com/library/en-us/winsock/winsock/wsaioctl_2.asp
>mentions SIO_RCVALL_MCAST and adds:
>
>   Setting this ioctl requires Administrator privilege on the local
>   computer. SIO_RCVALL_MCAST is available only in Windows 2000 and
>   later versions of Windows.

>It doesn't looks to me like there is an easy way to add this feature
>for win32 systems.

lookat http://www.nmsl.cs.ucsb.edu/MulticastSocketsBook/
they have a win32 sample also bsd,solaris,linux ..

BTW. multicast has been around a long time...

>The current patch doesn't add new requirements and may just not work
>if your OS don't support multicast or your switch drop these packets
>or any other problem happens. While I would prefer a solution where
>you can at compile or runtime detect that there is multicast enable
>the patch is ok.
>
>Speaking of which: if I ping 224.0.0.1 I should get a reply from
>myself?! Yes/no? If yes we can use this to test if the software
>supports multicast at all.

Might work, but you will have to check the rfc's to see if icmp packets (ping) 
will work on multicast.