path: root/net
diff options
authorOussama Ghorbel <ou.ghorbel@gmail.com>2013-10-03 14:49:26 +0100
committerDavid S. Miller <davem@davemloft.net>2013-10-07 12:32:26 -0400
commit582442d6d5bc74c1e11a2515f9387d3d227278e2 (patch)
treed970c591069cfe7b006368ad2541ba8d2038f398 /net
parent3573540cafa4296dd60f8be02f2aecaa31047525 (diff)
ipv6: Allow the MTU of ipip6 tunnel to be set below 1280
The (inner) MTU of a ipip6 (IPv4-in-IPv6) tunnel cannot be set below 1280, which is the minimum MTU in IPv6. However, there should be no IPv6 on the tunnel interface at all, so the IPv6 rules should not apply. More info at https://bugzilla.kernel.org/show_bug.cgi?id=15530 This patch allows to check the minimum MTU for ipv6 tunnel according to these rules: -In case the tunnel is configured with ipip6 mode the minimum MTU is 68. -In case the tunnel is configured with ip6ip6 or any mode the minimum MTU is 1280. Signed-off-by: Oussama Ghorbel <ou.ghorbel@gmail.com> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
1 files changed, 10 insertions, 2 deletions
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index a791552e042..583b77e2f69 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1430,9 +1430,17 @@ ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
static int
ip6_tnl_change_mtu(struct net_device *dev, int new_mtu)
- if (new_mtu < IPV6_MIN_MTU) {
- return -EINVAL;
+ struct ip6_tnl *tnl = netdev_priv(dev);
+ if (tnl->parms.proto == IPPROTO_IPIP) {
+ if (new_mtu < 68)
+ return -EINVAL;
+ } else {
+ if (new_mtu < IPV6_MIN_MTU)
+ return -EINVAL;
+ if (new_mtu > 0xFFF8 - dev->hard_header_len)
+ return -EINVAL;
dev->mtu = new_mtu;
return 0;