RE : [lwip-users] Join Multicast Group

[Frédéric BERNON]

To get multicast working (and I confirm you that it's work on lwIP 1.3.0), you 
have to set LWIP_IGMP=1 in your lwipopts.h file, AND, your netif should have 
the flag NETIF_FLAG_IGMP set in the "netif::flags".

It could be something like this in your driver code :

netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_LINK_UP | 
NETIF_FLAG_IGMP;

About SO_REUSEADDR, it's not supported yet, but it's not strictly necessary. 
The only problem you could got is you cannot have two sockets opened on the 
same port to receive twice one multicast stream.
  
====================================
Frédéric BERNON 
HYMATOM SA 
Chef de projet informatique 
Microsoft Certified Professional 
Tél. : +33 (0)4-67-87-61-10 
Fax. : +33 (0)4-67-70-85-44 
Email : address@hidden 
Web Site : http://www.hymatom.fr 

Plan d'accès au siège social 

====================================
P Avant d'imprimer, penser à l'environnement


-----Message d'origine-----
De : address@hidden [mailto:address@hidden De la part de Mathias Zenger
Envoyé : mercredi 15 juillet 2009 13:53
À : Mailing list for lwIP users
Objet : AW: [lwip-users] Join Multicast Group


Hi Kieran,

Regarding the reuse option you were right. I found the following entry in opt.h

/* ---------- Socket Options ---------- */
/* Enable SO_REUSEADDR and SO_REUSEPORT options */
#ifdef SO_REUSE
/* I removed the lot since this was an ugly hack. It broke the raw-API.
   It also came with many ugly goto's, Christiaan Simons. */ #error "SO_REUSE 
currently unavailable, this was a hack" #endif

So this is the reason (missing SO_REUSE) why my call to setsockopt in socket.c 
failed:

setsockopt(fd_socket, SOL_SOCKET, SO_REUSEADDR, &set_true, sizeof(set_true))

Any other version where this is implemented? (Although I am not sur if I really 
need it). Still unable to join a group - I continue with debugging...

Regards,
Mathias




-----Ursprüngliche Nachricht-----
Von: address@hidden
[mailto:address@hidden Auftrag von Kieran Mansley
Gesendet: Dienstag, 14. Juli 2009 16:47
An: Mailing list for lwIP users
Betreff: Re: [lwip-users] Join Multicast Group


On Tue, 2009-07-14 at 14:41 +0200, Mathias Zenger wrote:
> Since it is possible to enable LWIP_IGMP I thought
> this feature would be supported by lwIP. Does anybody have an 
> explanation for the failures or can somebody even provide me a working 
> example?

lwIP should, I think, support IGMP multicast for UDP sockets.  I haven't done 
this myself, so can't help directly with a working example, but I would first 
try it without binding multiple sockets to the same address. I.e. get rid of 
the SO_REUSEADDR stuff, in case that is causing a problem.

Kieran



_______________________________________________
lwip-users mailing list
address@hidden http://lists.nongnu.org/mailman/listinfo/lwip-users




_______________________________________________
lwip-users mailing list
address@hidden http://lists.nongnu.org/mailman/listinfo/lwip-users

Frédéric BERNON.vcf
Description: Frédéric BERNON.vcf