Index: doc/src/sgml/func.sgml
===================================================================
RCS file: /cvsroot/pgsql-server/doc/src/sgml/func.sgml,v
retrieving revision 1.145
diff -c -c -r1.145 func.sgml
*** doc/src/sgml/func.sgml	20 Mar 2003 18:58:02 -0000	1.145
--- doc/src/sgml/func.sgml	21 Mar 2003 21:49:26 -0000
***************
*** 5900,5905 ****
--- 5900,5912 ----
  	<entry><literal>255.255.255.0</literal></entry>
         </row>
         <row>
+ 	<entry><function>hostmask</function>(<type>inet</type>)</entry>
+ 	<entry><type>inet</type></entry>
+ 	<entry>construct hostmask for network</entry>
+ 	<entry><literal>hostmask('192.168.23.20/30')</literal></entry>
+ 	<entry><literal>0.0.0.3</literal></entry>
+        </row>
+        <row>
  	<entry><literal><function>network</function>(<type>inet</type>)</literal></entry>
  	<entry><type>cidr</type></entry>
  	<entry>extract network part of address</entry>
Index: src/backend/utils/adt/network.c
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/utils/adt/network.c,v
retrieving revision 1.38
diff -c -c -r1.38 network.c
*** src/backend/utils/adt/network.c	13 Nov 2002 00:39:47 -0000	1.38
--- src/backend/utils/adt/network.c	21 Mar 2003 21:49:34 -0000
***************
*** 605,610 ****
--- 605,650 ----
  	PG_RETURN_INET_P(dst);
  }
  
+ Datum
+ network_hostmask(PG_FUNCTION_ARGS)
+ {
+ 	inet	   *ip = PG_GETARG_INET_P(0);
+ 	inet	   *dst;
+ 
+ 	dst = (inet *) palloc(VARHDRSZ + sizeof(inet_struct));
+ 	/* make sure any unused bits are zeroed */
+ 	MemSet(dst, 0, VARHDRSZ + sizeof(inet_struct));
+ 
+ 	if (ip_family(ip) == AF_INET)
+ 	{
+ 		/* It's an IP V4 address: */
+ 		unsigned long mask = 0xffffffff;
+ 
+ 		/*
+ 		 * Only shift if the mask len is < 32 bits ..
+ 		 */
+ 
+ 		if (ip_bits(ip) < 32)
+ 			mask >>= ip_bits(ip);
+ 		else
+ 			mask = 0;
+ 
+ 		ip_v4addr(dst) = htonl(mask);
+ 
+ 		ip_bits(dst) = 32;
+ 	}
+ 	else
+ 		/* Go for an IPV6 address here, before faulting out: */
+ 		elog(ERROR, "unknown address family (%d)", ip_family(ip));
+ 
+ 	ip_family(dst) = ip_family(ip);
+ 	ip_type(dst) = 0;
+ 	VARATT_SIZEP(dst) = VARHDRSZ
+ 		+ ((char *) &ip_v4addr(dst) - (char *) VARDATA(dst))
+ 		+ ip_addrsize(dst);
+ 
+ 	PG_RETURN_INET_P(dst);
+ }
  
  /*
   * Convert a value of a network datatype to an approximate scalar value.
Index: src/include/catalog/pg_proc.h
===================================================================
RCS file: /cvsroot/pgsql-server/src/include/catalog/pg_proc.h,v
retrieving revision 1.289
diff -c -c -r1.289 pg_proc.h
*** src/include/catalog/pg_proc.h	20 Mar 2003 18:58:02 -0000	1.289
--- src/include/catalog/pg_proc.h	21 Mar 2003 21:49:42 -0000
***************
*** 2358,2363 ****
--- 2358,2365 ----
  DESCR("show address octets only");
  DATA(insert OID = 730 (  text				PGNSP PGUID 12 f f t f i 1 25 "869"  network_show - _null_ ));
  DESCR("show all parts of inet/cidr value");
+ DATA(insert OID = 1362 (  hostmask			PGNSP PGUID 12 f f t f i 1 869 "869"	network_hostmask - _null_ ));
+ DESCR("hostmask of address");
  DATA(insert OID = 1713 (  inet				PGNSP PGUID 12 f f t f i 1 869 "25"  text_inet - _null_ ));
  DESCR("text to inet");
  DATA(insert OID = 1714 (  cidr				PGNSP PGUID 12 f f t f i 1 650 "25"  text_cidr - _null_ ));