1 files changed, 33 insertions, 0 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index df14815a3b8c..a7dd088d5fc9 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -176,6 +176,7 @@ EXPORT_SYMBOL(__ip_dev_find);
 static void rtmsg_ifa(int event, struct in_ifaddr *, struct nlmsghdr *, u32);
 
 static BLOCKING_NOTIFIER_HEAD(inetaddr_chain);
+static BLOCKING_NOTIFIER_HEAD(inetaddr_validator_chain);
 static void inet_del_ifa(struct in_device *in_dev, struct in_ifaddr **ifap,
                          int destroy);
 #ifdef CONFIG_SYSCTL
@@ -441,6 +442,8 @@ static int __inet_insert_ifa(struct in_ifaddr *ifa, struct nlmsghdr *nlh,
 {
         struct in_device *in_dev = ifa->ifa_dev;
         struct in_ifaddr *ifa1, **ifap, **last_primary;
+        struct in_validator_info ivi;
+        int ret;
 
         ASSERT_RTNL();
 
@@ -471,6 +474,23 @@ static int __inet_insert_ifa(struct in_ifaddr *ifa, struct nlmsghdr *nlh,
                 }
         }
 
+        /* Allow any devices that wish to register ifaddr validtors to weigh
+         * in now, before changes are committed.  The rntl lock is serializing
+         * access here, so the state should not change between a validator call
+         * and a final notify on commit.  This isn't invoked on promotion under
+         * the assumption that validators are checking the address itself, and
+         * not the flags.
+         */
+        ivi.ivi_addr = ifa->ifa_address;
+        ivi.ivi_dev = ifa->ifa_dev;
+        ret = blocking_notifier_call_chain(&inetaddr_validator_chain,
+                                           NETDEV_UP, &ivi);
+        ret = notifier_to_errno(ret);
+        if (ret) {
+                inet_free_ifa(ifa);
+                return ret;
+        }
+
         if (!(ifa->ifa_flags & IFA_F_SECONDARY)) {
                 prandom_seed((__force u32) ifa->ifa_local);
                 ifap = last_primary;
@@ -1356,6 +1376,19 @@ int unregister_inetaddr_notifier(struct notifier_block *nb)
 }
 EXPORT_SYMBOL(unregister_inetaddr_notifier);
 
+int register_inetaddr_validator_notifier(struct notifier_block *nb)
+{
+        return blocking_notifier_chain_register(&inetaddr_validator_chain, nb);
+}
+EXPORT_SYMBOL(register_inetaddr_validator_notifier);
+
+int unregister_inetaddr_validator_notifier(struct notifier_block *nb)
+{
+        return blocking_notifier_chain_unregister(&inetaddr_validator_chain,
+            nb);
+}
+EXPORT_SYMBOL(unregister_inetaddr_validator_notifier);
+
 /* Rename ifa_labels for a device name change. Make some effort to preserve
  * existing alias numbering and to create unique labels if possible.
 */