[Linux-cluster] Multicast ccsd

[Lazar Obradovic]

Jonathan, 

thanks for mcast support in ccsd. 

However, it seems that you have forgoten to set mcast_ttl for a socket,
so mcast wouldn't have any sence, since mcast with ttl == 1 is same as
broadcast for many networks. 

All you have to do is just add something like: 
---8<---
char ttl = 10; 

if (setsockopt(sfd, IPPROTO_IP, IP_MULTICAST_TTL, 
    &ttl, sizeof (ttl) < 0 )) {
    log_err("Unable to set mcast ttl.\n");
    error = -errno;
    goto fail;
}
--->8--- 

ttl could be defined somewhere outside join_group(), or ever fetched
from argv, which also goes for cman_tool. 

Also, try not to use 224.0.0.0/23, as it is reserved, so we might get
into trouble with default values. 224.0.0.1 is reserved for all mcast
capable hosts, so even non-cluster members (potential or not) would get
ccsd announcements. 

We might even request one mcast address to be assigned for linux-cluster
project, so we can officialy use it. 


btw, to all developers: it was so uncool to remove 2.6.7 kernel patch :(
2.6.8.1 has a problem with tg3 driver (some autonegotiation issues), so
it's completly unusable.

-- 
Lazar Obradovic, System Engineer
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