1 files changed, 36 insertions, 1 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index e1846b97ee69..b5fd116c046a 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1459,6 +1459,21 @@ static bool ipv6_use_optimistic_addr(struct net *net,
 #endif
 }
 
+static bool ipv6_allow_optimistic_dad(struct net *net,
+				      struct inet6_dev *idev)
+{
+#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
+	if (!idev)
+		return false;
+	if (!net->ipv6.devconf_all->optimistic_dad && !idev->cnf.optimistic_dad)
+		return false;
+
+	return true;
+#else
+	return false;
+#endif
+}
+
 static int ipv6_get_saddr_eval(struct net *net,
 			       struct ipv6_saddr_score *score,
 			       struct ipv6_saddr_dst *dst,
@@ -1968,6 +1983,8 @@ static void addrconf_dad_stop(struct inet6_ifaddr *ifp, int dad_failed)
 		spin_lock_bh(&ifp->lock);
 		addrconf_del_dad_work(ifp);
 		ifp->flags |= IFA_F_TENTATIVE;
+		if (dad_failed)
+			ifp->flags &= ~IFA_F_OPTIMISTIC;
 		spin_unlock_bh(&ifp->lock);
 		if (dad_failed)
 			ipv6_ifa_notify(0, ifp);
@@ -4257,6 +4274,7 @@ static void __net_exit if6_proc_net_exit(struct net *net)
 static struct pernet_operations if6_proc_net_ops = {
 	.init = if6_proc_net_init,
 	.exit = if6_proc_net_exit,
+	.async = true,
 };
 
 int __init if6_proc_init(void)
@@ -4500,6 +4518,9 @@ static int inet6_addr_modify(struct inet6_ifaddr *ifp, u32 ifa_flags,
 	    (ifp->flags & IFA_F_TEMPORARY || ifp->prefix_len != 64))
 		return -EINVAL;
 
+	if (!(ifp->flags & IFA_F_TENTATIVE) || ifp->flags & IFA_F_DADFAILED)
+		ifa_flags &= ~IFA_F_OPTIMISTIC;
+
 	timeout = addrconf_timeout_fixup(valid_lft, HZ);
 	if (addrconf_finite_timeout(timeout)) {
 		expires = jiffies_to_clock_t(timeout * HZ);
@@ -4573,6 +4594,7 @@ inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
 	struct in6_addr *pfx, *peer_pfx;
 	struct inet6_ifaddr *ifa;
 	struct net_device *dev;
+	struct inet6_dev *idev;
 	u32 valid_lft = INFINITY_LIFE_TIME, preferred_lft = INFINITY_LIFE_TIME;
 	u32 ifa_flags;
 	int err;
@@ -4606,7 +4628,19 @@ inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
 
 	/* We ignore other flags so far. */
 	ifa_flags &= IFA_F_NODAD | IFA_F_HOMEADDRESS | IFA_F_MANAGETEMPADDR |
-		     IFA_F_NOPREFIXROUTE | IFA_F_MCAUTOJOIN;
+		     IFA_F_NOPREFIXROUTE | IFA_F_MCAUTOJOIN | IFA_F_OPTIMISTIC;
+
+	idev = ipv6_find_idev(dev);
+	if (IS_ERR(idev))
+		return PTR_ERR(idev);
+
+	if (!ipv6_allow_optimistic_dad(net, idev))
+		ifa_flags &= ~IFA_F_OPTIMISTIC;
+
+	if (ifa_flags & IFA_F_NODAD && ifa_flags & IFA_F_OPTIMISTIC) {
+		NL_SET_ERR_MSG(extack, "IFA_F_NODAD and IFA_F_OPTIMISTIC are mutually exclusive");
+		return -EINVAL;
+	}
 
 	ifa = ipv6_get_ifaddr(net, pfx, dev, 1);
 	if (!ifa) {
@@ -6550,6 +6584,7 @@ static void __net_exit addrconf_exit_net(struct net *net)
 static struct pernet_operations addrconf_ops = {
 	.init = addrconf_init_net,
 	.exit = addrconf_exit_net,
+	.async = true,
 };
 
 static struct rtnl_af_ops inet6_ops __read_mostly = {