[NETLINK] Fix mc_list operations

[NETLINK] Fix mc_list operations

[Herbert Xu]

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Hi Dave:

While doing the 2.4 version of the netlink patch, I noticed a bug
in my mc_list code.  First of all it wasn't holding the table lock
when adding nodes to the list.  It also didn't take the node off
the list when multicast is switched off.

The following patch fixes it for 2.6.  I will simply fix it in the
2.4 version.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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===== net/netlink/af_netlink.c 1.61 vs edited =====
--- 1.61/net/netlink/af_netlink.c	2004-11-06 18:49:54 +11:00
+++ edited/net/netlink/af_netlink.c	2004-11-11 15:09:40 +11:00
@@ -471,9 +471,16 @@
 			return err;
 	}
 
-	nlk->groups = nladdr->nl_groups;
-	if (nladdr->nl_groups)
+	if (!nladdr->nl_groups && !nlk->groups)
+		return 0;
+
+	netlink_table_grab();
+	if (nlk->groups && !nladdr->nl_groups)
+		__sk_del_bind_node(sk);
+	else if (!nlk->groups && nladdr->nl_groups)
 		sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
+	nlk->groups = nladdr->nl_groups;
+	netlink_table_ungrab();
 
 	return 0;
 }

Re: [NETLINK] Fix mc_list operations

[David S. Miller]

On Thu, 11 Nov 2004 15:21:36 +1100
Herbert Xu <herbert@gondor.apana.org.au> wrote:

> While doing the 2.4 version of the netlink patch, I noticed a bug
> in my mc_list code.  First of all it wasn't holding the table lock
> when adding nodes to the list.  It also didn't take the node off
> the list when multicast is switched off.

Applied, thanks Herbert.