datapath: lisp: Relax MTU constraints.

[cascardo/ovs.git] / datapath / linux / compat / lisp.c

diff --git a/datapath/linux/compat/lisp.c b/datapath/linux/compat/lisp.c
index e5a6a7f..fa6da6c 100644 (file)
--- a/datapath/linux/compat/lisp.c
+++ b/datapath/linux/compat/lisp.c
@@ -114,6 +114,7 @@ struct lisphdr {
 };
 
 #define LISP_HLEN (sizeof(struct udphdr) + sizeof(struct lisphdr))
+#define LISP_MAX_MTU (IP_MAX_MTU - LISP_HLEN - sizeof(struct iphdr))
 
 static inline struct lisphdr *lisp_hdr(const struct sk_buff *skb)
 {
@@ -447,6 +448,15 @@ static netdev_tx_t lisp_dev_xmit(struct sk_buff *skb, struct net_device *dev)
 #endif
 }
 
+static int lisp_change_mtu(struct net_device *dev, int new_mtu)
+{
+       if (new_mtu < 68 || new_mtu > LISP_MAX_MTU)
+               return -EINVAL;
+
+       dev->mtu = new_mtu;
+       return 0;
+}
+
 static const struct net_device_ops lisp_netdev_ops = {
 #ifdef HAVE_DEV_TSTATS
        .ndo_init               = lisp_init,
@@ -456,7 +466,7 @@ static const struct net_device_ops lisp_netdev_ops = {
        .ndo_open               = lisp_open,
        .ndo_stop               = lisp_stop,
        .ndo_start_xmit         = lisp_dev_xmit,
-       .ndo_change_mtu         = eth_change_mtu,
+       .ndo_change_mtu         = lisp_change_mtu,
        .ndo_validate_addr      = eth_validate_addr,
        .ndo_set_mac_address    = eth_mac_addr,
 };
@@ -549,6 +559,10 @@ static int lisp_configure(struct net *net, struct net_device *dev,
        if (find_dev(net, dst_port))
                return -EBUSY;
 
+       err = lisp_change_mtu(dev, LISP_MAX_MTU);
+       if (err)
+               return err;
+
        err = register_netdevice(dev);
        if (err)
                return err;