1 files changed, 25 insertions, 0 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index dbc51af69017..924158393d04 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1265,6 +1265,31 @@ int ipv6_chk_same_addr(struct net *net, const struct in6_addr *addr,
         return ifp != NULL;
 }
 
+int ipv6_chk_prefix(struct in6_addr *addr, struct net_device *dev)
+{
+        struct inet6_dev *idev;
+        struct inet6_ifaddr *ifa;
+        int     onlink;
+
+        onlink = 0;
+        rcu_read_lock();
+        idev = __in6_dev_get(dev);
+        if (idev) {
+                read_lock_bh(&idev->lock);
+                for (ifa = idev->addr_list; ifa; ifa = ifa->if_next) {
+                        onlink = ipv6_prefix_equal(addr, &ifa->addr,
+                                                   ifa->prefix_len);
+                        if (onlink)
+                                break;
+                }
+                read_unlock_bh(&idev->lock);
+        }
+        rcu_read_unlock();
+        return onlink;
+}
+
+EXPORT_SYMBOL(ipv6_chk_prefix);
+
 struct inet6_ifaddr *ipv6_get_ifaddr(struct net *net, struct in6_addr *addr,
                                      struct net_device *dev, int strict)
 {