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Path: utzoo!linus!decvax!wivax!cadmus!harvard!seismo!brl-tgr!internet!dpk@BRL-VGR.ARPA
From: dpk@BRL-VGR.ARPA
Newsgroups: net.unix-wizards
Subject: brl-vgr Bug Report
Message-ID: <5764@brl-tgr.ARPA>
Date: Wed, 14-Nov-84 01:42:12 EST
Article-I.D.: brl-tgr.5764
Posted: Wed Nov 14 01:42:12 1984
Date-Received: Fri, 16-Nov-84 01:29:08 EST
Sender: news@brl-tgr.ARPA
Organization: Ballistic Research Lab
Lines: 51

Subject: netstat is grossly inefficient for stupid reason
Index:	ucb/netstat/inet.c 4.2BSD Fix

Description:
	In inet.c:inetname(), netstat stupidly checks for the
	special case of INADDR_ANY (a non-host) only after a linear
	search through the entire host table.  What is worse,
	it will search the ENTIRE table for every INADDR_ANY socket,
	looking for the non-existent entry.

Repeat-By:
	Run "netstat -a" and watch how slow it is.  To be more
	graphic, start up a bunch of processes which hang an accept()
	on INTERNET sockets (say 50 or 100), and make sure your host
	table has several hundred entries (like the ARPA host table).
	Your netstat -a will take FOREVER to complete.

Fix:
	This fix is trivial and will make netstat go MUCH MUCH faster,
	over an order of magnitude faster on our system for a netstat -a.
	I have included a diff listing, although the line number will be
	off by a constant due to a header we stuck on the file (~8 lines).
	Basically, move the check for INADDR_ANY before the search
	through the host table which you KNOW will fail.
	This is a reposting since it did not make it to Berkeley or
	onto the Bug List from MT. XINU.  This fix is EASY.

diff inet.c.old inet.c
4c4
<  * $Revision: 1.2 $
---
>  * $Revision: 1.3 $
6a7,9
>  * Revision 1.3  84/07/04  01:09:36  dpk
>  * Moved check for INADDR_ANY in inetname for efficiency
>  * 
12c15
< static char RCSid[] = "@(#)$Header: inet.c,v 1.2 84/07/04 01:07:20 dpk BRL $";
---
> static char RCSid[] = "@(#)$Header: inet.c,v 1.3 84/07/04 01:09:36 dpk BRL $";
312a316,319
> 	if (in.s_addr == INADDR_ANY) {	/* A quick check for the easy case */
> 		strcpy(line, "*");
> 		return (line);
> 	}
329,331c336
< 	if (in.s_addr == INADDR_ANY)
< 		strcpy(line, "*");
< 	else if (cp)
---
> 	if (cp)