3 files changed, 48 insertions, 3 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 91d3d96805d0..b12dae2b0b2d 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1029,6 +1029,11 @@ skip:
         }
 }
 
+static inline bool inetdev_valid_mtu(unsigned mtu)
+{
+        return mtu >= 68;
+}
+
 /* Called only under RTNL semaphore */
 
 static int inetdev_event(struct notifier_block *this, unsigned long event,
@@ -1048,6 +1053,10 @@ static int inetdev_event(struct notifier_block *this, unsigned long event,
                                 IN_DEV_CONF_SET(in_dev, NOXFRM, 1);
                                 IN_DEV_CONF_SET(in_dev, NOPOLICY, 1);
                         }
+                } else if (event == NETDEV_CHANGEMTU) {
+                        /* Re-enabling IP */
+                        if (inetdev_valid_mtu(dev->mtu))
+                                in_dev = inetdev_init(dev);
                 }
                 goto out;
         }
@@ -1058,7 +1067,7 @@ static int inetdev_event(struct notifier_block *this, unsigned long event,
                 dev->ip_ptr = NULL;
                 break;
         case NETDEV_UP:
-                if (dev->mtu < 68)
+                if (!inetdev_valid_mtu(dev->mtu))
                         break;
                 if (dev->flags & IFF_LOOPBACK) {
                         struct in_ifaddr *ifa;
@@ -1080,9 +1089,9 @@ static int inetdev_event(struct notifier_block *this, unsigned long event,
                 ip_mc_down(in_dev);
                 break;
         case NETDEV_CHANGEMTU:
-                if (dev->mtu >= 68)
+                if (inetdev_valid_mtu(dev->mtu))
                         break;
-                /* MTU falled under 68, disable IP */
+                /* disable IP when MTU is not enough */
         case NETDEV_UNREGISTER:
                 inetdev_destroy(in_dev);
                 break;
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index d985bd613d25..743f011b9a84 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -409,3 +409,38 @@ out:
 }
 
 EXPORT_SYMBOL_GPL(inet_twdr_twcal_tick);
+
+void inet_twsk_purge(struct net *net, struct inet_hashinfo *hashinfo,
+                     struct inet_timewait_death_row *twdr, int family)
+{
+        struct inet_timewait_sock *tw;
+        struct sock *sk;
+        struct hlist_node *node;
+        int h;
+
+        local_bh_disable();
+        for (h = 0; h < (hashinfo->ehash_size); h++) {
+                struct inet_ehash_bucket *head =
+                        inet_ehash_bucket(hashinfo, h);
+                rwlock_t *lock = inet_ehash_lockp(hashinfo, h);
+restart:
+                write_lock(lock);
+                sk_for_each(sk, node, &head->twchain) {
+
+                        tw = inet_twsk(sk);
+                        if (!net_eq(twsk_net(tw), net) ||
+                            tw->tw_family != family)
+                                continue;
+
+                        atomic_inc(&tw->tw_refcnt);
+                        write_unlock(lock);
+                        inet_twsk_deschedule(tw, twdr);
+                        inet_twsk_put(tw);
+
+                        goto restart;
+                }
+                write_unlock(lock);
+        }
+        local_bh_enable();
+}
+EXPORT_SYMBOL_GPL(inet_twsk_purge);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 37ca3843c40b..3dfbc21e555a 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2388,6 +2388,7 @@ static int __net_init tcp_sk_init(struct net *net)
 static void __net_exit tcp_sk_exit(struct net *net)
 {
         inet_ctl_sock_destroy(net->ipv4.tcp_sock);
+        inet_twsk_purge(net, &tcp_hashinfo, &tcp_death_row, AF_INET);
 }
 
 static struct pernet_operations __net_initdata tcp_sk_ops = {