(feature change request) remove link-layer generated routes from netstat -r

[Giorgos Keramidas]

On 2006-02-24 11:32, Nikos Vassiliadis <nvass at teledomenet.gr> wrote:
>On Thursday 23 February 2006 20:24, Giorgos Keramidas wrote:
>>
>> ... about using a switch to shorten the netstat output (by not
>> displaying the link-layer entries):
>>
>> How about making the new behavior non-default, i.e. toggled by a -s
>> switch to the netstat -r command?
>>
>>         % netstat -rs
>>
>> Then 's' can stand for 'short' output, and everyone can experiment with
>> the new feature.  Then, after a couple of minor releases, if we find
>> that this is a feature that is very often used, we can make it the
>> default.
>
> That would be a well balanced compromise. I can live with it.

Unfortunately, the -s option is taken already.  It enables the display
of statistics.  A possible alternative is the -c (compact) option,
i.e. with a patch similar to the following:

%%%
Index: main.c
===================================================================
RCS file: /home/ncvs/src/usr.bin/netstat/main.c,v
retrieving revision 1.81
diff -u -r1.81 main.c
--- main.c	28 Dec 2005 20:36:55 -0000	1.81
+++ main.c	24 Feb 2006 12:54:39 -0000
@@ -286,6 +286,7 @@
 int	aflag;		/* show all sockets (including servers) */
 int	Bflag;		/* show information about bpf consumers */
 int	bflag;		/* show i/f total bytes in/out */
+int	cflag;		/* show compact output format */
 int	dflag;		/* show i/f dropped packets */
 int	gflag;		/* show group (multicast) routing or stats */
 int	hflag;		/* show counters in human readable format */
@@ -316,7 +317,7 @@
 
 	af = AF_UNSPEC;
 
-	while ((ch = getopt(argc, argv, "AaBbdf:ghI:iLlM:mN:np:rSstuWw:z")) != -1)
+	while ((ch = getopt(argc, argv, "AaBbcdf:ghI:iLlM:mN:np:rSstuWw:z")) != -1)
 		switch(ch) {
 		case 'A':
 			Aflag = 1;
@@ -330,6 +331,9 @@
 		case 'b':
 			bflag = 1;
 			break;
+		case 'c':
+			cflag = 1;
+			break;
 		case 'd':
 			dflag = 1;
 			break;
Index: netstat.1
===================================================================
RCS file: /home/ncvs/src/usr.bin/netstat/netstat.1,v
retrieving revision 1.56
diff -u -r1.56 netstat.1
--- netstat.1	18 Dec 2005 19:38:43 -0000	1.56
+++ netstat.1	24 Feb 2006 12:59:34 -0000
@@ -32,7 +32,7 @@
 .\"	@(#)netstat.1	8.8 (Berkeley) 4/18/94
 .\" $FreeBSD: src/usr.bin/netstat/netstat.1,v 1.56 2005/12/18 19:38:43 csjp Exp $
 .\"
-.Dd September 7, 2005
+.Dd February 24, 2006
 .Dt NETSTAT 1
 .Os
 .Sh NAME
@@ -209,7 +209,7 @@
 .Bk -words
 .Nm
 .Fl r
-.Op Fl AanW
+.Op Fl AacnW
 .Op Fl f Ar address_family
 .Op Fl M Ar core
 .Op Fl N Ar system
@@ -231,6 +231,13 @@
 .Dv RTF_PRCLONING
 parent route);
 normally these routes are not shown.
+If
+.Fl c
+is also present,
+hide routes that were generated by link-layer events (i.e. by ARP),
+resulting in a more
+.Dq compact
+output format.
 When
 .Fl W
 is also present,
Index: netstat.h
===================================================================
RCS file: /home/ncvs/src/usr.bin/netstat/netstat.h,v
retrieving revision 1.47
diff -u -r1.47 netstat.h
--- netstat.h	28 Dec 2005 20:36:55 -0000	1.47
+++ netstat.h	24 Feb 2006 12:55:35 -0000
@@ -39,6 +39,7 @@
 extern int	Aflag;	/* show addresses of protocol control block */
 extern int	aflag;	/* show all sockets (including servers) */
 extern int	bflag;	/* show i/f total bytes in/out */
+extern int	cflag;	/* show compact output format */
 extern int	dflag;	/* show i/f dropped packets */
 extern int	gflag;	/* show group (multicast) routing or stats */
 extern int	hflag;	/* show counters in human readable format */
Index: route.c
===================================================================
RCS file: /home/ncvs/src/usr.bin/netstat/route.c,v
retrieving revision 1.76
diff -u -r1.76 route.c
--- route.c	13 May 2005 16:31:10 -0000	1.76
+++ route.c	24 Feb 2006 12:54:29 -0000
@@ -720,6 +720,13 @@
 			return;
 	}
 
+	/*
+	 * Skip routes that were generated by link-layer (i.e. ARP) if we are
+	 * in `compact output' mode.
+	 */
+	if (rt->rt_flags & RTF_LLINFO && cflag)
+		return;
+
 	bzero(&addr, sizeof(addr));
 	if ((sa = kgetsa(rt_key(rt))))
 		bcopy(sa, &addr, sa->sa_len);
%%%