dup() and dup2() support for socket descriptors

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@1884 42af7a65-404d-4744-a932-0658087f49c3

include/net/uip/uip-tcp.h

@@ -134,6 +134,7 @@ struct uip_conn
                            * connection */
   uint16 initialmss;      /* Initial maximum segment size for the
                            * connection */
+  uint8  crefs;           /* Reference counts on this instance */
   uint8  sa;              /* Retransmission time-out calculation state
                            * variable */
   uint8  sv;              /* Retransmission time-out calculation state

include/net/uip/uip-udp.h

@@ -77,6 +77,7 @@ struct uip_udp_conn
   uint16 lport;           /* The local port number in network byte order */
   uint16 rport;           /* The remote port number in network byte order */
   uint8  ttl;             /* Default time-to-live */
+  uint8  crefs;           /* Reference counts on this instance */
 
   /* Defines the list of UDP callbacks */