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From: Archie Cobbs <archie@whistle.com>
Message-Id: <199710032051.NAA23325@bubba.whistle.com>
Subject: bpfattach() bug
To: freebsd-hackers@freebsd.org
Date: Fri, 3 Oct 1997 13:51:40 -0700 (PDT)
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FYI-

The bpfattach() routine makes an assumption that it will only
ever be called at boot time (specifically, before any /dev/bpf*
devices are opened).

This assumption is false, for example, in any case where an
interface can be created dynamically (such as ours).

The following patch fixes this in both -stable and -current.

-Archie

___________________________________________________________________________
Archie Cobbs   *   Whistle Communications, Inc.  *   http://www.whistle.com

*** /usr/src/sys/net/bpf.c	Wed Apr  9 00:31:05 1997
--- bpf.c	Fri Oct  3 13:11:44 1997
***************
*** 115,120 ****
--- 115,121 ----
   */
  static struct bpf_if	*bpf_iflist;
  static struct bpf_d	bpf_dtab[NBPFILTER];
+ static int		bpf_dtab_init;
  
  static int	bpf_allocbufs __P((struct bpf_d *));
  static void	bpf_attachd __P((struct bpf_d *d, struct bpf_if *bp));
***************
*** 1293,1301 ****
  	/*
  	 * Mark all the descriptors free if this hasn't been done.
  	 */
! 	if (!D_ISFREE(&bpf_dtab[0]))
  		for (i = 0; i < NBPFILTER; ++i)
  			D_MARKFREE(&bpf_dtab[i]);
  
  	if (bootverbose)
  		printf("bpf: %s%d attached\n", ifp->if_name, ifp->if_unit);
--- 1294,1304 ----
  	/*
  	 * Mark all the descriptors free if this hasn't been done.
  	 */
! 	if (!bpf_dtab_init) {
  		for (i = 0; i < NBPFILTER; ++i)
  			D_MARKFREE(&bpf_dtab[i]);
+ 		bpf_dtab_init = 1;
+ 	}
  
  	if (bootverbose)
  		printf("bpf: %s%d attached\n", ifp->if_name, ifp->if_unit);