[PATCH 4.6 073/203] geneve: fix max_mtu setting

Greg Kroah-Hartman
2016-07-25T21:36:54Z

From: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>

[ Upstream commit d5d5e8d55732c7c35c354e45e3b0af2795978a57 ]

For ipv6+udp+geneve encapsulation data, the max_mtu should subtract
sizeof(ipv6hdr), instead of sizeof(iphdr).

Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/geneve.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -1092,12 +1092,17 @@ static netdev_tx_t geneve_xmit(struct sk

static int __geneve_change_mtu(struct net_device *dev, int new_mtu, bool strict)
{
+ struct geneve_dev *geneve = netdev_priv(dev);
/* The max_mtu calculation does not take account of GENEVE
* options, to avoid excluding potentially valid
* configurations.
*/
- int max_mtu = IP_MAX_MTU - GENEVE_BASE_HLEN - sizeof(struct iphdr)
- - dev->hard_header_len;
+ int max_mtu = IP_MAX_MTU - GENEVE_BASE_HLEN - dev->hard_header_len;
+
+ if (geneve->remote.sa.sa_family == AF_INET6)
+ max_mtu -= sizeof(struct ipv6hdr);
+ else
+ max_mtu -= sizeof(struct iphdr);

if (new_mtu < 68)
return -EINVAL;