net - IP_NODEFRAG option for IPv4 socket

this patch is implementing IP_NODEFRAG option for IPv4 socket.
The reason is, there's no other way to send out the packet with user
customized header of the reassembly part.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/in.h b/include/linux/in.h
index 583c76f..41d88a4 100644
--- a/include/linux/in.h
+++ b/include/linux/in.h
@@ -85,6 +85,7 @@
 #define IP_RECVORIGDSTADDR   IP_ORIGDSTADDR
 
 #define IP_MINTTL       21
+#define IP_NODEFRAG     22
 
 /* IP_MTU_DISCOVER values */
 #define IP_PMTUDISC_DONT		0	/* Never send DF frames */