[PATCH] fix ACK processing after netlink_dump_start

[PATCH] fix ACK processing after netlink_dump_start

[Denis V. Lunev]

Revert to original netlink behavior. Do not reply with ACK if the
netlink dump has bees successfully started.

libnl has been broken by the cd40b7d3983c708aabe3d3008ec64ffce56d33b0
The following command reproduce the problem:
   /nl-route-get 192.168.1.1

Signed-off-by: Denis V. Lunev <den@openvz.org>

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 98e313e..44a8b41 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1565,7 +1565,10 @@ int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
 
 	netlink_dump(sk);
 	sock_put(sk);
-	return 0;
+
+	/* We successfully started a dump, by returning -EINTR we
+	 * signal not to send ACK even if it was requested */
+	return -EINTR;
 }
 
 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
@@ -1619,17 +1622,21 @@ int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
 
 		/* Only requests are handled by the kernel */
 		if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
-			goto skip;
+			goto ack;
 
 		/* Skip control messages */
 		if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
-			goto skip;
+			goto ack;
 
 		err = cb(skb, nlh);
-skip:
+		if (err == -EINTR)
+			goto skip;
+
+ack:
 		if (nlh->nlmsg_flags & NLM_F_ACK || err)
 			netlink_ack(skb, nlh, err);
 
+skip:
 	        msglen = NLMSG_ALIGN(nlh->nlmsg_len);
 		if (msglen > skb->len)
 			msglen = skb->len;

Re: [PATCH] fix ACK processing after netlink_dump_start

[Joseph Fannin]

On Tue, Oct 23, 2007 at 06:40:23PM +0400, Denis V. Lunev wrote:
> Revert to original netlink behavior. Do not reply with ACK if the
> netlink dump has bees successfully started.
>
> libnl has been broken by the cd40b7d3983c708aabe3d3008ec64ffce56d33b0
> The following command reproduce the problem:
>    /nl-route-get 192.168.1.1
>
> Signed-off-by: Denis V. Lunev <den@openvz.org>

Network Manager works correctly here with this patch applied against
Linus's current -git.

(Sorry for the lack of response before -- I think I forgot to ask to
be CC'd on replies, and found the discussion of this in archives
only this morning.)

--
Joseph Fannin
jfannin@gmail.com

Re: [PATCH] fix ACK processing after netlink_dump_start

[Thomas Graf]

* Denis V. Lunev <den@openvz.org> 2007-10-23 18:40
> Revert to original netlink behavior. Do not reply with ACK if the
> netlink dump has bees successfully started.
> 
> libnl has been broken by the cd40b7d3983c708aabe3d3008ec64ffce56d33b0
> The following command reproduce the problem:
>    /nl-route-get 192.168.1.1
> 
> Signed-off-by: Denis V. Lunev <den@openvz.org>

ACK. Thank you for taking care of this.

Re: [PATCH] fix ACK processing after netlink_dump_start

[David Miller]

From: Thomas Graf <tgraf@suug.ch>
Date: Tue, 23 Oct 2007 18:34:28 +0200

> * Denis V. Lunev <den@openvz.org> 2007-10-23 18:40
> > Revert to original netlink behavior. Do not reply with ACK if the
> > netlink dump has bees successfully started.
> > 
> > libnl has been broken by the cd40b7d3983c708aabe3d3008ec64ffce56d33b0
> > The following command reproduce the problem:
> >    /nl-route-get 192.168.1.1
> > 
> > Signed-off-by: Denis V. Lunev <den@openvz.org>
> 
> ACK. Thank you for taking care of this.

Applied, thanks everyone!