geneve: fix max_mtu setting

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>

diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index cc39cef..9b3dc3c 100644 (file)
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -1072,12 +1072,17 @@ static netdev_tx_t geneve_xmit(struct sk_buff *skb, struct net_device *dev)
 
 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;