1 files changed, 24 insertions, 11 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 1593289155ff..b0e1430b64f1 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2646,7 +2646,8 @@ static int addrconf_ifdown(struct net_device *dev, int how)
 
                 write_lock_bh(&addrconf_hash_lock);
                 while ((ifa = *bifa) != NULL) {
-                        if (ifa->idev == idev) {
+                        if (ifa->idev == idev &&
+                            (how || !(ifa->flags&IFA_F_PERMANENT))) {
                                 *bifa = ifa->lst_next;
                                 ifa->lst_next = NULL;
                                 addrconf_del_timer(ifa);
@@ -2686,18 +2687,30 @@ static int addrconf_ifdown(struct net_device *dev, int how)
                 write_lock_bh(&idev->lock);
         }
 #endif
-        while ((ifa = idev->addr_list) != NULL) {
-                idev->addr_list = ifa->if_next;
-                ifa->if_next = NULL;
-                ifa->dead = 1;
-                addrconf_del_timer(ifa);
-                write_unlock_bh(&idev->lock);
+        bifa = &idev->addr_list;
+        while ((ifa = *bifa) != NULL) {
+                if (how == 0 && (ifa->flags&IFA_F_PERMANENT)) {
+                        /* Retain permanent address on admin down */
+                        bifa = &ifa->if_next;
+
+                        /* Restart DAD if needed when link comes back up */
+                        if ( !((dev->flags&(IFF_NOARP|IFF_LOOPBACK)) ||
+                               idev->cnf.accept_dad <= 0 ||
+                               (ifa->flags & IFA_F_NODAD)))
+                                ifa->flags |= IFA_F_TENTATIVE;
+                } else {
+                        *bifa = ifa->if_next;
+                        ifa->if_next = NULL;
 
-                __ipv6_ifa_notify(RTM_DELADDR, ifa);
-                atomic_notifier_call_chain(&inet6addr_chain, NETDEV_DOWN, ifa);
-                in6_ifa_put(ifa);
+                        ifa->dead = 1;
+                        write_unlock_bh(&idev->lock);
 
-                write_lock_bh(&idev->lock);
+                        __ipv6_ifa_notify(RTM_DELADDR, ifa);
+                        atomic_notifier_call_chain(&inet6addr_chain, NETDEV_DOWN, ifa);
+                        in6_ifa_put(ifa);
+
+                        write_lock_bh(&idev->lock);
+                }
         }
         write_unlock_bh(&idev->lock);