[PATCH] udp: fix for unicast RX path optimization

[PATCH] udp: fix for unicast RX path optimization

[Jorge Boncompte [DTI2]]

	Commits 5051ebd275de672b807c28d93002c2fb0514a3c9 and
5051ebd275de672b807c28d93002c2fb0514a3c9 ("ipv[46]: udp: optimize unicast RX
path") broke some programs.

	After upgrading a L2TP server to 2.6.33 it started to fail, tunnels going up an
down, after the 10th tunnel came up. My modified rp-l2tp uses a global
unconnected socket bound to (INADDR_ANY, 1701) and one connected socket per
tunnel after parameter negotiation.

	After ten sockets were open and due to mixed parameters to
udp[46]_lib_lookup2() kernel started to drop packets.

Signed-off-by: Jorge Boncompte [DTI2] <jorge@dti2.net>
---
diff -uNrp linux-2.6.33/net/ipv4/udp.c kernel-netns/net/ipv4/udp.c
--- linux-2.6.33/net/ipv4/udp.c	2010-02-24 19:52:17.000000000 +0100
+++ kernel-netns/net/ipv4/udp.c	2010-04-08 15:07:21.888717449 +0200
@@ -471,8 +471,8 @@ static struct sock *__udp4_lib_lookup(st
 			if (hslot->count < hslot2->count)
 				goto begin;

-			result = udp4_lib_lookup2(net, INADDR_ANY, sport,
-						  daddr, hnum, dif,
+			result = udp4_lib_lookup2(net, saddr, sport,
+						  INADDR_ANY, hnum, dif,
 						  hslot2, slot2);
 		}
 		rcu_read_unlock();
diff -uNrp linux-2.6.33/net/ipv6/udp.c kernel-netns/net/ipv6/udp.c
--- linux-2.6.33/net/ipv6/udp.c	2010-02-24 19:52:17.000000000 +0100
+++ kernel-netns/net/ipv6/udp.c	2010-04-08 15:07:57.081396901 +0200
@@ -258,8 +258,8 @@ static struct sock *__udp6_lib_lookup(st
 			if (hslot->count < hslot2->count)
 				goto begin;

-			result = udp6_lib_lookup2(net, &in6addr_any, sport,
-						  daddr, hnum, dif,
+			result = udp6_lib_lookup2(net, saddr, sport,
+						  &in6addr_any, hnum, dif,
 						  hslot2, slot2);
 		}
 		rcu_read_unlock();

Re: [PATCH] udp: fix for unicast RX path optimization

[Eric Dumazet]

Le jeudi 08 avril 2010 à 16:56 +0200, Jorge Boncompte [DTI2] a écrit :
> 	Commits 5051ebd275de672b807c28d93002c2fb0514a3c9 and
> 5051ebd275de672b807c28d93002c2fb0514a3c9 ("ipv[46]: udp: optimize unicast RX
> path") broke some programs.
> 
> 	After upgrading a L2TP server to 2.6.33 it started to fail, tunnels going up an
> down, after the 10th tunnel came up. My modified rp-l2tp uses a global
> unconnected socket bound to (INADDR_ANY, 1701) and one connected socket per
> tunnel after parameter negotiation.
> 
> 	After ten sockets were open and due to mixed parameters to
> udp[46]_lib_lookup2() kernel started to drop packets.
> 
> Signed-off-by: Jorge Boncompte [DTI2] <jorge@dti2.net>

Oops...

Thank you for finding this bug, this is indeed the right fix.

This is a stable candidate. David, can you catch it even if Jorge didnt
sent you a copy ?

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>

Re: [PATCH] udp: fix for unicast RX path optimization

[David Miller]

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 08 Apr 2010 17:12:27 +0200

> This is a stable candidate. David, can you catch it even if Jorge didnt
> sent you a copy ?

It went to netdev and thus patchwork and I both have it :-)

Re: [PATCH] udp: fix for unicast RX path optimization

[David Miller]

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 08 Apr 2010 17:12:27 +0200

> Le jeudi 08 avril 2010 à 16:56 +0200, Jorge Boncompte [DTI2] a écrit :
>> 	Commits 5051ebd275de672b807c28d93002c2fb0514a3c9 and
>> 5051ebd275de672b807c28d93002c2fb0514a3c9 ("ipv[46]: udp: optimize unicast RX
>> path") broke some programs.
>> 
>> 	After upgrading a L2TP server to 2.6.33 it started to fail, tunnels going up an
>> down, after the 10th tunnel came up. My modified rp-l2tp uses a global
>> unconnected socket bound to (INADDR_ANY, 1701) and one connected socket per
>> tunnel after parameter negotiation.
>> 
>> 	After ten sockets were open and due to mixed parameters to
>> udp[46]_lib_lookup2() kernel started to drop packets.
>> 
>> Signed-off-by: Jorge Boncompte [DTI2] <jorge@dti2.net>
 ...
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>

Applied and queued up for -stable.