1 files changed, 48 insertions, 3 deletions

diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 1cbeba5edff9..a52f50187b54 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -211,6 +211,48 @@ static inline int ip_finish_output2(struct sk_buff *skb)
         return -EINVAL;
 }
 
+static int ip_finish_output_gso(struct sk_buff *skb)
+{
+        netdev_features_t features;
+        struct sk_buff *segs;
+        int ret = 0;
+
+        /* common case: locally created skb or seglen is <= mtu */
+        if (((IPCB(skb)->flags & IPSKB_FORWARDED) == 0) ||
+              skb_gso_network_seglen(skb) <= ip_skb_dst_mtu(skb))
+                return ip_finish_output2(skb);
+
+        /* Slowpath -  GSO segment length is exceeding the dst MTU.
+         *
+         * This can happen in two cases:
+         * 1) TCP GRO packet, DF bit not set
+         * 2) skb arrived via virtio-net, we thus get TSO/GSO skbs directly
+         * from host network stack.
+         */
+        features = netif_skb_features(skb);
+        segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
+        if (IS_ERR(segs)) {
+                kfree_skb(skb);
+                return -ENOMEM;
+        }
+
+        consume_skb(skb);
+
+        do {
+                struct sk_buff *nskb = segs->next;
+                int err;
+
+                segs->next = NULL;
+                err = ip_fragment(segs, ip_finish_output2);
+
+                if (err && ret == 0)
+                        ret = err;
+                segs = nskb;
+        } while (segs);
+
+        return ret;
+}
+
 static int ip_finish_output(struct sk_buff *skb)
 {
 #if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM)
@@ -220,10 +262,13 @@ static int ip_finish_output(struct sk_buff *skb)
                 return dst_output(skb);
         }
 #endif
-        if (skb->len > ip_skb_dst_mtu(skb) && !skb_is_gso(skb))
+        if (skb_is_gso(skb))
+                return ip_finish_output_gso(skb);
+
+        if (skb->len > ip_skb_dst_mtu(skb))
                 return ip_fragment(skb, ip_finish_output2);
-        else
-                return ip_finish_output2(skb);
+
+        return ip_finish_output2(skb);
 }
 
 int ip_mc_output(struct sock *sk, struct sk_buff *skb)