Re: [PATCH 1/1 net-2.6] Re-enable IP when MTU > 68
From: Breno Leitao <hidden>
Date: 2008-08-30 17:57:59
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
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 <redacted> ---
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 91d3d96..27193dd 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;