2.6.32 and Multicast group membership

2.6.32 and Multicast group membership

[Mr. Berkley Shands]

starting in 2.6.32, my multicast connections stop getting data after 
60-100 seconds.
The identical user code works fine under 2.6.22 through 2.6.31.

The NIC (an intel 82586) has two ports on the same subnet
(eth0 at 172.16.21.55/24 and eth1 at 172.16.21.56/24)

      if (setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char*)&req, 
sizeof(req)))
      {
         perror("setsockopt IP_ADD_MEMBERSHIP failed");
         ::exit(-1);
      }

If I do ADD_MEMBERSHIP on just one of these interfaces, the sockets 
still get data.
But if I join on both interfaces, one or both will stop getting packets
after 60-100 seconds. Sniffing with tcpdump shows the Cisco layer 3 switch
is not getting its responses back to keep the multicast group open.
The HP layer 2 switch does not seem to care, it keeps the data flowing 
regardless
of which physical port the join is executed on.

Changing IP_MULTICAST_ALL has no effect :-(
Did I miss something? New code that I have to specify to keep the Cisco 
happy?

tia

Berkley


-- 

// E. F. Berkley Shands, MSc//

** Exegy Inc.**

349 Marshall Road, Suite 100

St. Louis , MO  63119

Direct:  (314) 218-3600 X450

Cell:  (314) 303-2546

Office:  (314) 218-3600

Fax:  (314) 218-3601

 

The Usual Disclaimer follows...

 

Re: 2.6.32 and Multicast group membership

[Mark Smith]

On Tue, 01 Jun 2010 16:39:00 -0500
"Mr. Berkley Shands" <bshands@exegy.com> wrote:

> starting in 2.6.32, my multicast connections stop getting data after 
> 60-100 seconds.
> The identical user code works fine under 2.6.22 through 2.6.31.
> 
> The NIC (an intel 82586) has two ports on the same subnet
> (eth0 at 172.16.21.55/24 and eth1 at 172.16.21.56/24)
> 
>       if (setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char*)&req, 
> sizeof(req)))
>       {
>          perror("setsockopt IP_ADD_MEMBERSHIP failed");
>          ::exit(-1);
>       }
> 
> If I do ADD_MEMBERSHIP on just one of these interfaces, the sockets 
> still get data.
> But if I join on both interfaces, one or both will stop getting packets
> after 60-100 seconds. Sniffing with tcpdump shows the Cisco layer 3 switch
> is not getting its responses back to keep the multicast group open.

While it could be a kernel change, that sounds like it might also be
related to IGMP snooping on the Cisco switch. Any changes made to that
recently?

> The HP layer 2 switch does not seem to care, it keeps the data flowing 
> regardless
> of which physical port the join is executed on.
> 

This is expected behaviour on a 'dumb' layer 2 switch i.e. one that
doesn't perform IGMP snooping and therefore doesn't suppress multicasts
towards end-nodes that aren't subscribed. That further suggests a
change on the Cisco.

FWIW, I'm having no trouble with IPv4 multicast under 2.6.33, plugged
into Cisco switch, with IGMP snooping, but not multicast suppression,
enabled.

> Changing IP_MULTICAST_ALL has no effect :-(
> Did I miss something? New code that I have to specify to keep the Cisco 
> happy?
> 
> tia
> 
> Berkley
> 
> 
> -- 
> 
> // E. F. Berkley Shands, MSc//
> 
> ** Exegy Inc.**
> 
> 349 Marshall Road, Suite 100
> 
> St. Louis , MO  63119
> 
> Direct:  (314) 218-3600 X450
> 
> Cell:  (314) 303-2546
> 
> Office:  (314) 218-3600
> 
> Fax:  (314) 218-3601
> 
>  
> 
> The Usual Disclaimer follows...
> 
>  
> 
> 
> --
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