diff --git a/include/net/protocol.h b/include/net/protocol.h
index 357691f..a29cb29 100644
--- a/include/net/protocol.h
+++ b/include/net/protocol.h
@@ -76,6 +76,7 @@
 };
 #define INET_PROTOSW_REUSE 0x01	     /* Are ports automatically reusable? */
 #define INET_PROTOSW_PERMANENT 0x02  /* Permanent protocols are unremovable. */
+#define INET_PROTOSW_ICSK      0x04  /* Is this an inet_connection_sock? */
 
 extern struct net_protocol *inet_protocol_base;
 extern struct net_protocol *inet_protos[MAX_INET_PROTOS];