1 files changed, 18 insertions, 0 deletions

diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c
index 5cf10b777b7e..a917903d5e97 100644
--- a/net/ipv4/ip_vti.c
+++ b/net/ipv4/ip_vti.c
@@ -156,6 +156,7 @@ static netdev_tx_t vti_xmit(struct sk_buff *skb, struct net_device *dev,
         struct dst_entry *dst = skb_dst(skb);
         struct net_device *tdev;        /* Device to other host */
         int err;
+        int mtu;
 
         if (!dst) {
                 dev->stats.tx_carrier_errors++;
@@ -192,6 +193,23 @@ static netdev_tx_t vti_xmit(struct sk_buff *skb, struct net_device *dev,
                         tunnel->err_count = 0;
         }
 
+        mtu = dst_mtu(dst);
+        if (skb->len > mtu) {
+                skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
+                if (skb->protocol == htons(ETH_P_IP)) {
+                        icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
+                                  htonl(mtu));
+                } else {
+                        if (mtu < IPV6_MIN_MTU)
+                                mtu = IPV6_MIN_MTU;
+
+                        icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
+                }
+
+                dst_release(dst);
+                goto tx_error;
+        }
+
         skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(dev)));
         skb_dst_set(skb, dst);
         skb->dev = skb_dst(skb)->dev;