ipv: Re-enable IP when MTU > 68
Re-enable IP when the MTU gets back to a valid size.
This patch just checks if the in_dev is NULL on a NETDEV_CHANGEMTU event
and if MTU is valid (bigger than 68), then re-enable in_dev.
Also a function that checks valid MTU size was created.
Signed-off-by: Breno Leitao <leitao@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 91d3d96..b12dae2 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1029,6 +1029,11 @@
}
}
+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 @@
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 @@
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 @@
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;