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Commit 06770843 authored by Breno Leitao's avatar Breno Leitao Committed by David S. Miller
Browse files

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: default avatarBreno Leitao <leitao@linux.vnet.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9d7d7402

net/ipv4/devinet.c

+12 −3
Original line number Diff line number Diff line
@@ -1029,6 +1029,11 @@ static void inetdev_changename(struct net_device *dev, struct in_device *in_dev) 
	}

}



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;