ipv6: Use POSTDAD state

This patch makes use of the new POSTDAD state.  This prevents
a race between DAD completion and failure.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 24 insertions, 5 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 2e42162c9042..7c769fa81d97 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1406,10 +1406,27 @@ static void addrconf_dad_stop(struct inet6_ifaddr *ifp, int dad_failed)
                 ipv6_del_addr(ifp);
 }
 
+static int addrconf_dad_end(struct inet6_ifaddr *ifp)
+{
+        int err = -ENOENT;
+
+        spin_lock(&ifp->state_lock);
+        if (ifp->state == INET6_IFADDR_STATE_DAD) {
+                ifp->state = INET6_IFADDR_STATE_POSTDAD;
+                err = 0;
+        }
+        spin_unlock(&ifp->state_lock);
+
+        return err;
+}
+
 void addrconf_dad_failure(struct inet6_ifaddr *ifp)
 {
         struct inet6_dev *idev = ifp->idev;
 
+        if (addrconf_dad_end(ifp))
+                return;
+
         if (net_ratelimit())
                 printk(KERN_INFO "%s: IPv6 duplicate address %pI6c detected!\n",
                         ifp->idev->dev->name, &ifp->addr);
@@ -2712,6 +2729,7 @@ static int addrconf_ifdown(struct net_device *dev, int how)
 
                         /* Flag it for later restoration when link comes up */
                         ifa->flags |= IFA_F_TENTATIVE;
+                        ifa->state = INET6_IFADDR_STATE_DAD;
 
                         write_unlock_bh(&idev->lock);
 
@@ -2883,6 +2901,9 @@ static void addrconf_dad_timer(unsigned long data)
         struct inet6_dev *idev = ifp->idev;
         struct in6_addr mcaddr;
 
+        if (!ifp->probes && addrconf_dad_end(ifp))
+                goto out;
+
         read_lock(&idev->lock);
         if (idev->dead || !(idev->if_flags & IF_READY)) {
                 read_unlock(&idev->lock);
@@ -2956,12 +2977,10 @@ static void addrconf_dad_run(struct inet6_dev *idev)
         read_lock_bh(&idev->lock);
         list_for_each_entry(ifp, &idev->addr_list, if_list) {
                 spin_lock(&ifp->lock);
-                if (!(ifp->flags & IFA_F_TENTATIVE)) {
-                        spin_unlock(&ifp->lock);
-                        continue;
-                }
+                if (ifp->flags & IFA_F_TENTATIVE &&
+                    ifp->state == INET6_IFADDR_STATE_DAD)
+                        addrconf_dad_kick(ifp);
                 spin_unlock(&ifp->lock);
-                addrconf_dad_kick(ifp);
         }
         read_unlock_bh(&idev->lock);
 }