Patch "net: ipv6: send NS for DAD when link operationally up" has been added to the 4.14-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    net: ipv6: send NS for DAD when link operationally up

to the 4.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     net-ipv6-send-ns-for-dad-when-link-operationally-up.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Wed Dec 20 18:17:52 CET 2017
From: Mike Manning <mmanning@brocade.com>
Date: Mon, 25 Sep 2017 22:01:36 +0100
Subject: net: ipv6: send NS for DAD when link operationally up

From: Mike Manning <mmanning@brocade.com>


[ Upstream commit 1f372c7bfb23286d2bf4ce0423ab488e86b74bb2 ]

The NS for DAD are sent on admin up as long as a valid qdisc is found.
A race condition exists by which these packets will not egress the
interface if the operational state of the lower device is not yet up.
The solution is to delay DAD until the link is operationally up
according to RFC2863. Rather than only doing this, follow the existing
code checks by deferring IPv6 device initialization altogether. The fix
allows DAD on devices like tunnels that are controlled by userspace
control plane. The fix has no impact on regular deployments, but means
that there is no IPv6 connectivity until the port has been opened in
the case of port-based network access control, which should be
desirable.

Signed-off-by: Mike Manning <mmanning@brocade.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/ipv6/addrconf.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -303,10 +303,10 @@ static struct ipv6_devconf ipv6_devconf_
 	.disable_policy		= 0,
 };
 
-/* Check if a valid qdisc is available */
-static inline bool addrconf_qdisc_ok(const struct net_device *dev)
+/* Check if link is ready: is it up and is a valid qdisc available */
+static inline bool addrconf_link_ready(const struct net_device *dev)
 {
-	return !qdisc_tx_is_noop(dev);
+	return netif_oper_up(dev) && !qdisc_tx_is_noop(dev);
 }
 
 static void addrconf_del_rs_timer(struct inet6_dev *idev)
@@ -451,7 +451,7 @@ static struct inet6_dev *ipv6_add_dev(st
 
 	ndev->token = in6addr_any;
 
-	if (netif_running(dev) && addrconf_qdisc_ok(dev))
+	if (netif_running(dev) && addrconf_link_ready(dev))
 		ndev->if_flags |= IF_READY;
 
 	ipv6_mc_init_dev(ndev);
@@ -3404,7 +3404,7 @@ static int addrconf_notify(struct notifi
 			/* restore routes for permanent addresses */
 			addrconf_permanent_addr(dev);
 
-			if (!addrconf_qdisc_ok(dev)) {
+			if (!addrconf_link_ready(dev)) {
 				/* device is not ready yet. */
 				pr_info("ADDRCONF(NETDEV_UP): %s: link is not ready\n",
 					dev->name);
@@ -3419,7 +3419,7 @@ static int addrconf_notify(struct notifi
 				run_pending = 1;
 			}
 		} else if (event == NETDEV_CHANGE) {
-			if (!addrconf_qdisc_ok(dev)) {
+			if (!addrconf_link_ready(dev)) {
 				/* device is still not ready. */
 				break;
 			}


Patches currently in stable-queue which might be from mmanning@brocade.com are

queue-4.14/net-ipv6-send-ns-for-dad-when-link-operationally-up.patch