net: Discard and warn about LRO'd skbs received for forwarding

Add skb_warn_if_lro() to test whether an skb was received with LRO and
warn if so.

Change br_forward(), ip_forward() and ip6_forward() to call it) and
discard the skb if it returns true.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/ipv4/ip_forward.c b/net/ipv4/ip_forward.c
index 37d36a3f33cd..da14725916d3 100644
--- a/net/ipv4/ip_forward.c
+++ b/net/ipv4/ip_forward.c
@@ -56,6 +56,9 @@ int ip_forward(struct sk_buff *skb)
         struct rtable *rt;      /* Route we use */
         struct ip_options * opt = &(IPCB(skb)->opt);
 
+        if (skb_warn_if_lro(skb))
+                goto drop;
+
         if (!xfrm4_policy_check(NULL, XFRM_POLICY_FWD, skb))
                 goto drop;