1 files changed, 109 insertions, 75 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 85100c1ac761..6913a82f4669 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -900,15 +900,95 @@ out:
         goto out2;
 }
 
+enum cleanup_prefix_rt_t {
+        CLEANUP_PREFIX_RT_NOP,    /* no cleanup action for prefix route */
+        CLEANUP_PREFIX_RT_DEL,    /* delete the prefix route */
+        CLEANUP_PREFIX_RT_EXPIRE, /* update the lifetime of the prefix route */
+};
+
+/*
+ * Check, whether the prefix for ifp would still need a prefix route
+ * after deleting ifp. The function returns one of the CLEANUP_PREFIX_RT_*
+ * constants.
+ *
+ * 1) we don't purge prefix if address was not permanent.
+ *    prefix is managed by its own lifetime.
+ * 2) we also don't purge, if the address was IFA_F_NOPREFIXROUTE.
+ * 3) if there are no addresses, delete prefix.
+ * 4) if there are still other permanent address(es),
+ *    corresponding prefix is still permanent.
+ * 5) if there are still other addresses with IFA_F_NOPREFIXROUTE,
+ *    don't purge the prefix, assume user space is managing it.
+ * 6) otherwise, update prefix lifetime to the
+ *    longest valid lifetime among the corresponding
+ *    addresses on the device.
+ *    Note: subsequent RA will update lifetime.
+ **/
+static enum cleanup_prefix_rt_t
+check_cleanup_prefix_route(struct inet6_ifaddr *ifp, unsigned long *expires)
+{
+        struct inet6_ifaddr *ifa;
+        struct inet6_dev *idev = ifp->idev;
+        unsigned long lifetime;
+        enum cleanup_prefix_rt_t action = CLEANUP_PREFIX_RT_DEL;
+
+        *expires = jiffies;
+
+        list_for_each_entry(ifa, &idev->addr_list, if_list) {
+                if (ifa == ifp)
+                        continue;
+                if (!ipv6_prefix_equal(&ifa->addr, &ifp->addr,
+                                       ifp->prefix_len))
+                        continue;
+                if (ifa->flags & (IFA_F_PERMANENT | IFA_F_NOPREFIXROUTE))
+                        return CLEANUP_PREFIX_RT_NOP;
+
+                action = CLEANUP_PREFIX_RT_EXPIRE;
+
+                spin_lock(&ifa->lock);
+
+                lifetime = addrconf_timeout_fixup(ifa->valid_lft, HZ);
+                /*
+                 * Note: Because this address is
+                 * not permanent, lifetime <
+                 * LONG_MAX / HZ here.
+                 */
+                if (time_before(*expires, ifa->tstamp + lifetime * HZ))
+                        *expires = ifa->tstamp + lifetime * HZ;
+                spin_unlock(&ifa->lock);
+        }
+
+        return action;
+}
+
+static void
+cleanup_prefix_route(struct inet6_ifaddr *ifp, unsigned long expires, bool del_rt)
+{
+        struct rt6_info *rt;
+
+        rt = addrconf_get_prefix_route(&ifp->addr,
+                                       ifp->prefix_len,
+                                       ifp->idev->dev,
+                                       0, RTF_GATEWAY | RTF_DEFAULT);
+        if (rt) {
+                if (del_rt)
+                        ip6_del_rt(rt);
+                else {
+                        if (!(rt->rt6i_flags & RTF_EXPIRES))
+                                rt6_set_expires(rt, expires);
+                        ip6_rt_put(rt);
+                }
+        }
+}
+
+
 /* This function wants to get referenced ifp and releases it before return */
 
 static void ipv6_del_addr(struct inet6_ifaddr *ifp)
 {
-        struct inet6_ifaddr *ifa, *ifn;
-        struct inet6_dev *idev = ifp->idev;
         int state;
-        int deleted = 0, onlink = 0;
-        unsigned long expires = jiffies;
+        enum cleanup_prefix_rt_t action = CLEANUP_PREFIX_RT_NOP;
+        unsigned long expires;
 
         spin_lock_bh(&ifp->state_lock);
         state = ifp->state;
@@ -922,7 +1002,7 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp)
         hlist_del_init_rcu(&ifp->addr_lst);
         spin_unlock_bh(&addrconf_hash_lock);
 
-        write_lock_bh(&idev->lock);
+        write_lock_bh(&ifp->idev->lock);
 
         if (ifp->flags&IFA_F_TEMPORARY) {
                 list_del(&ifp->tmp_list);
@@ -933,45 +1013,13 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp)
                 __in6_ifa_put(ifp);
         }
 
-        list_for_each_entry_safe(ifa, ifn, &idev->addr_list, if_list) {
-                if (ifa == ifp) {
-                        list_del_init(&ifp->if_list);
-                        __in6_ifa_put(ifp);
+        if (ifp->flags & IFA_F_PERMANENT && !(ifp->flags & IFA_F_NOPREFIXROUTE))
+                action = check_cleanup_prefix_route(ifp, &expires);
 
-                        if (!(ifp->flags & IFA_F_PERMANENT) || onlink > 0)
-                                break;
-                        deleted = 1;
-                        continue;
-                } else if (ifp->flags & IFA_F_PERMANENT) {
-                        if (ipv6_prefix_equal(&ifa->addr, &ifp->addr,
-                                              ifp->prefix_len)) {
-                                if (ifa->flags & IFA_F_PERMANENT) {
-                                        onlink = 1;
-                                        if (deleted)
-                                                break;
-                                } else {
-                                        unsigned long lifetime;
-
-                                        if (!onlink)
-                                                onlink = -1;
-
-                                        spin_lock(&ifa->lock);
-
-                                        lifetime = addrconf_timeout_fixup(ifa->valid_lft, HZ);
-                                        /*
-                                         * Note: Because this address is
-                                         * not permanent, lifetime <
-                                         * LONG_MAX / HZ here.
-                                         */
-                                        if (time_before(expires,
-                                                        ifa->tstamp + lifetime * HZ))
-                                                expires = ifa->tstamp + lifetime * HZ;
-                                        spin_unlock(&ifa->lock);
-                                }
-                        }
-                }
-        }
-        write_unlock_bh(&idev->lock);
+        list_del_init(&ifp->if_list);
+        __in6_ifa_put(ifp);
+
+        write_unlock_bh(&ifp->idev->lock);
 
         addrconf_del_dad_timer(ifp);
 
@@ -979,38 +1027,9 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp)
 
         inet6addr_notifier_call_chain(NETDEV_DOWN, ifp);
 
-        /*
-         * Purge or update corresponding prefix
-         *
-         * 1) we don't purge prefix here if address was not permanent.
-         *    prefix is managed by its own lifetime.
-         * 2) if there are no addresses, delete prefix.
-         * 3) if there are still other permanent address(es),
-         *    corresponding prefix is still permanent.
-         * 4) otherwise, update prefix lifetime to the
-         *    longest valid lifetime among the corresponding
-         *    addresses on the device.
-         *    Note: subsequent RA will update lifetime.
-         *
-         * --yoshfuji
-         */
-        if ((ifp->flags & IFA_F_PERMANENT) && onlink < 1) {
-                struct rt6_info *rt;
-
-                rt = addrconf_get_prefix_route(&ifp->addr,
-                                               ifp->prefix_len,
-                                               ifp->idev->dev,
-                                               0, RTF_GATEWAY | RTF_DEFAULT);
-
-                if (rt) {
-                        if (onlink == 0) {
-                                ip6_del_rt(rt);
-                                rt = NULL;
-                        } else if (!(rt->rt6i_flags & RTF_EXPIRES)) {
-                                rt6_set_expires(rt, expires);
-                        }
-                }
-                ip6_rt_put(rt);
+        if (action != CLEANUP_PREFIX_RT_NOP) {
+                cleanup_prefix_route(ifp, expires,
+                        action == CLEANUP_PREFIX_RT_DEL);
         }
 
         /* clean up prefsrc entries */
@@ -3636,6 +3655,7 @@ static int inet6_addr_modify(struct inet6_ifaddr *ifp, u32 ifa_flags,
         clock_t expires;
         unsigned long timeout;
         bool was_managetempaddr;
+        bool had_prefixroute;
 
         if (!valid_lft || (prefered_lft > valid_lft))
                 return -EINVAL;
@@ -3664,6 +3684,8 @@ static int inet6_addr_modify(struct inet6_ifaddr *ifp, u32 ifa_flags,
 
         spin_lock_bh(&ifp->lock);
         was_managetempaddr = ifp->flags & IFA_F_MANAGETEMPADDR;
+        had_prefixroute = ifp->flags & IFA_F_PERMANENT &&
+                          !(ifp->flags & IFA_F_NOPREFIXROUTE);
         ifp->flags &= ~(IFA_F_DEPRECATED | IFA_F_PERMANENT | IFA_F_NODAD |
                         IFA_F_HOMEADDRESS | IFA_F_MANAGETEMPADDR |
                         IFA_F_NOPREFIXROUTE);
@@ -3679,6 +3701,18 @@ static int inet6_addr_modify(struct inet6_ifaddr *ifp, u32 ifa_flags,
         if (!(ifa_flags & IFA_F_NOPREFIXROUTE)) {
                 addrconf_prefix_route(&ifp->addr, ifp->prefix_len, ifp->idev->dev,
                                       expires, flags);
+        } else if (had_prefixroute) {
+                enum cleanup_prefix_rt_t action;
+                unsigned long rt_expires;
+
+                write_lock_bh(&ifp->idev->lock);
+                action = check_cleanup_prefix_route(ifp, &rt_expires);
+                write_unlock_bh(&ifp->idev->lock);
+
+                if (action != CLEANUP_PREFIX_RT_NOP) {
+                        cleanup_prefix_route(ifp, rt_expires,
+                                action == CLEANUP_PREFIX_RT_DEL);
+                }
         }
 
         if (was_managetempaddr || ifp->flags & IFA_F_MANAGETEMPADDR) {