ipv4: Don't do expensive useless work during inetdev destroy.

commit fbd40ea0180a2d328c5adc61414dc8bab9335ce2 upstream.

When an inetdev is destroyed, every address assigned to the interface
is removed.  And in this scenerio we do two pointless things which can
be very expensive if the number of assigned interfaces is large:

1) Address promotion.  We are deleting all addresses, so there is no
   point in doing this.

2) A full nf conntrack table purge for every address.  We only need to
   do this once, as is already caught by the existing
   masq_dev_notifier so masq_inet_event() can skip this.

Reported-by: Solar Designer <solar@openwall.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Tested-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Moritz Muehlenhoff <jmm@inutil.org>
[ luis: backported to 3.16:
  - file rename: nf_nat_masquerade_ipv4.c -> ipt_MASQUERADE.c ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index aa4b9990dd7a5837a013d512cbb55a7311fba0e5..710fe64fb2f7ce70412f105361c081855aa9d6d0 100644 (file)
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -326,6 +326,9 @@ static void __inet_del_ifa(struct in_device *in_dev, struct in_ifaddr **ifap,
 
        ASSERT_RTNL();
 
+       if (in_dev->dead)
+               goto no_promotions;
+
        /* 1. Deleting primary ifaddr forces deletion all secondaries
         * unless alias promotion is set
         **/
@@ -372,6 +375,7 @@ static void __inet_del_ifa(struct in_device *in_dev, struct in_ifaddr **ifap,
                        fib_del_ifaddr(ifa, ifa1);
        }
 
+no_promotions:
        /* 2. Unlink it */
 
        *ifap = ifa1->ifa_next;

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 255aa9946fe785a2577fbdb23560288599c1ba0a..7d736cd3ee91ff7baf3445b215d819c93de9df37 100644 (file)
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -812,6 +812,9 @@ void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim)
                subnet = 1;
        }
 
+       if (in_dev->dead)
+               goto no_promotions;
+
        /* Deletion is more complicated than add.
         * We should take care of not to delete too much :-)
         *
@@ -887,6 +890,7 @@ void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim)
                }
        }
 
+no_promotions:
        if (!(ok & BRD_OK))
                fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);
        if (subnet && ifa->ifa_prefixlen < 31) {

diff --git a/net/ipv4/netfilter/ipt_MASQUERADE.c b/net/ipv4/netfilter/ipt_MASQUERADE.c
index 00352ce0f0dec43f0f0d08e0e77115c97625ab89..3bc1c98aa2f0db15674f090957ab63a7748c8a5c 100644 (file)
--- a/net/ipv4/netfilter/ipt_MASQUERADE.c
+++ b/net/ipv4/netfilter/ipt_MASQUERADE.c
@@ -128,10 +128,18 @@ static int masq_inet_event(struct notifier_block *this,
                           unsigned long event,
                           void *ptr)
 {
-       struct net_device *dev = ((struct in_ifaddr *)ptr)->ifa_dev->dev;
+       struct in_device *idev = ((struct in_ifaddr *)ptr)->ifa_dev;
        struct netdev_notifier_info info;
 
-       netdev_notifier_info_init(&info, dev);
+       /* The masq_dev_notifier will catch the case of the device going
+        * down.  So if the inetdev is dead and being destroyed we have
+        * no work to do.  Otherwise this is an individual address removal
+        * and we have to perform the flush.
+        */
+       if (idev->dead)
+               return NOTIFY_DONE;
+
+       netdev_notifier_info_init(&info, idev->dev);
        return masq_device_event(this, event, &info);
 }