Bug?

[James Morris]

On Mon, 20 Mar 2000, Alexander Demenshin wrote:

> Hello,
> 
> 	So... linux-2.3.99-pre2 (as from ftp.kernel.org; not pre2-5),
> 	netfilter-1.0.0alpha (iptables). Netfilter built as modules,
> 	all modules were inserted.
> 	
> 	Rules:
> 	
> 		iptables -A OUTPUT -t mangle	-s 127.1.0.0/24 -j MARK --set 0x1777
> 		iptables -A INPUT		-s 127.1.0.0/24 -j QUEUE
> 	
> 	(there were other rules but I think they are irrelevant).
> 	
> 	Next... One vc:
> 	
> 		ping 127.1.1.1
> 		
> 	Other vc:
> 	
> 		ipq_client
> 		
> 	Everything was fine. Then client was interrupted for some time,
> 	restarted again, then again interrupted... but ping was active
> 	all the time.
> 	Next attepmt to run ipq_client (after few minutes) -> kernel panic.
> 	There were some messages in log, like:
> 	
> Mar 20 05:42:12 nest kernel: ip_queue: error notifying peer 1887, resetting state and flushing queue 
> Mar 20 05:43:02 nest kernel: ip_queue: error notifying peer 2013, resetting state and flushing queue 
> Mar 20 05:46:52 nest kernel: ip_queue: error notifying peer 2034, resetting state and flushing queue 
> Mar 20 05:48:48 nest kernel: ip_queue: error notifying peer 2035, resetting state and flushing queue 
> 
> 	That's all. Sorry, no exact OOPS data - no record in logs, only on
> 	console... It was really hard lockup...

Please try applying the patch below:


diff -ur --exclude=*.[oa] --exclude=.* linux-2.3.99-pre2-4/net/ipv4/netfilter/ip_queue.c linux/net/ipv4/netfilter/ip_queue.c
--- linux-2.3.99-pre2-4/net/ipv4/netfilter/ip_queue.c	Sat Mar 18 23:22:33 2000
+++ linux/net/ipv4/netfilter/ip_queue.c	Sun Mar 19 13:16:43 2000
@@ -491,7 +491,7 @@
 	skb = netlink_build_message(e, &status);
 	if (skb == NULL)
 		return status;
-	return netlink_unicast(nfnl, skb, nlq->peer.pid, 0);
+	return netlink_unicast(nfnl, skb, nlq->peer.pid, MSG_DONTWAIT);
 }
 
 static struct sk_buff *


> 
> 	Discovery: when rule with QUEUE target is active, packets are queued
> 	(client accepts several of them after starting), but... Is it correct
> 	behavior? If there is no client - should we queue them?

That is correct (if ip_queue.o is loaded), but I'm not sure if it's a good
idea in practice.


- James.
--
James Morris
<jmorris@intercode.com.au>