diff mbox

Multicast routing stops functioning after 4G multicast packets recived.

Message ID 20140107170145.317040@gmx.com
State RFC, archived
Delegated to: David Miller
Headers show

Commit Message

Bob Falken Jan. 7, 2014, 5:01 p.m. UTC 
Hello,

I patched, kernel 3.2.53 yesterday,
8774002632packets, and ~9.1TB later, the multicast routing seems to function properly. :)

Kudos for fixing this.

I will keep checking the next days.

As for IPv6 MR, my current setup i.e: the Multicast source, does not support IPv6, so cannot do a check for that natively.

Unless I can translate IPv4 multicast into IPv6 multicast easily, using some iptable prerouting rules(?).

Thanks again.


----- Original Message -----
From: Hannes Frederic Sowa
Sent: 01/05/14 12:38 AM
To: Julian Anastasov
Subject: Re: Multicast routing stops functioning after 4G multicast packets recived.
 On Sat, Jan 04, 2014 at 09:55:51PM +0200, Julian Anastasov wrote:
> 
> Hello,
> 
> On Thu, 19 Dec 2013, Bob Falken wrote:
> 
> > Hello, I have an issue after kernel 2.6.37 and above.
> > If i roll back to kernel 2.6.36.4 everything is fine.
> > if recive more than 4294967295 multicast packets, the kernel does not register the multicast packets. and multicast routing does not functioning.
> 
> ...
> 
> > I think there might be a variable in the kernel that get overflown. though i cannot be sure as im not a programmer. 
> > 
> > Let me know if you need more debug information.
> > 
> > Please help.  
> 
> As Hannes guessed, may be it is really the missing
> flags = FIB_LOOKUP_NOREF in ipmr_fib_lookup() when calling
> fib_rules_lookup(), we have an atomic_inc_not_zero() there that
> can stop to work after 4G lookups when rule's refcnt reaches 0.
> As result, fib_rules_lookup() can start to return -ESRCH.

I guess we should just try. I somehow forgot to look after that. Thanks
for reminding, Julian.

Bob, can you try with this patch again?

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Comments

Hannes Frederic Sowa Jan. 7, 2014, 5:43 p.m. UTC | #1 
On Tue, Jan 07, 2014 at 06:01:44PM +0100, Bob Falken wrote:
> Hello,
> 
> I patched, kernel 3.2.53 yesterday,
> 8774002632packets, and ~9.1TB later, the multicast routing seems to function properly. :)
> 
> Kudos for fixing this.
> 
> I will keep checking the next days.
> 
> As for IPv6 MR, my current setup i.e: the Multicast source, does not support IPv6, so cannot do a check for that natively.
> 
> Unless I can translate IPv4 multicast into IPv6 multicast easily, using some iptable prerouting rules(?).

Thank you for testing!

I'll review the RCU regions again and will prepare the patches (before
introduction of ebc0ffae5dfb44 ("fib: RCU conversion of fib_lookup()")
and after.

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diff mbox

Patch

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 421a249..b9b3472 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -157,9 +157,12 @@  static struct mr_table *ipmr_get_table(struct net *net, u32 id)
 static int ipmr_fib_lookup(struct net *net, struct flowi4 *flp4,
 struct mr_table **mrt)
 {
- struct ipmr_result res;
- struct fib_lookup_arg arg = { .result = &res};
 int err;
+ struct ipmr_result res;
+ struct fib_lookup_arg arg = {
+ .result = &res,
+ .flags = FIB_LOOKUP_NOREF,
+ };
 
 err = fib_rules_lookup(net->ipv4.mr_rules_ops,
 flowi4_to_flowi(flp4), 0, &arg);