udpv4: Handle large incoming UDP/IPv4 packets and support software UFO.

- validate and forward GSO UDP/IPv4 packets from untrusted sources.
- do software UFO if the outgoing device doesn't support UFO.

Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/udp.h b/include/net/udp.h
index 90e6ce5..5fb029f 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -207,4 +207,7 @@
 #endif
 
 extern void udp_init(void);
+
+extern int udp4_ufo_send_check(struct sk_buff *skb);
+extern struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, int features);
 #endif	/* _UDP_H */