kern/99500: [netgraph] [patch] netgraph doesn't honor the monitor interface flag

[Craig Leres]

>Number:         99500
>Category:       kern
>Synopsis:       [netgraph] [patch] netgraph doesn't honor the monitor interface flag
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Jun 26 22:30:26 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator:     Craig Leres
>Release:        FreeBSD 6.1-RELEASE i386
>Organization:
Lawrence Berkeley National Laboratory
>Environment:
	fox 128 % uname -a
	FreeBSD fox.ee.lbl.gov 6.1-RELEASE FreeBSD 6.1-RELEASE #3: Tue Jun 20 11:50:33 PDT 2006     leres at fox.ee.lbl.gov:/usr/src/6.1-RELEASE/sys/i386/compile/LBLSMP  i386

>Description:
	When using netgraph to "bond" two syskonnect gige interfaces
	together for a packet capture application, we see output
	errors on the pseudo interface that is the sum of the number
	of packets input on the two syskonnect NICs. Examination
	of the code reveals that this is because the packets cannot
	be transmitted out the pseudo interface.

>How-To-Repeat:
	This is our setup:

	    kldload ng_ether

	    ifconfig sk0 promisc -arp up
	    ifconfig sk1 promisc -arp up

	    ngctl mkpeer . eiface hook ether
	    ngctl mkpeer ngeth0: one2many lower one
	    ngctl connect sk0: ngeth0:lower lower many0
	    ngctl connect sk1: ngeth0:lower lower many1

	    ifconfig ngeth0 -arp monitor up

>Fix:
	The appended patch causes netgraph to check the monitor bit
	and discard the packet if it's set; it also increments the
	input packet counter (which perhaps it should always do?)

	I suspect there are other places in netgraph where this
	should be done.

===================================================================
RCS file: netgraph/RCS/ng_eiface.c,v
retrieving revision 1.1
diff -c -r1.1 netgraph/ng_eiface.c
*** netgraph/ng_eiface.c	2006/06/26 21:56:36	1.1
--- netgraph/ng_eiface.c	2006/06/26 22:14:40
***************
*** 25,31 ****
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
!  * $FreeBSD: src/sys/netgraph/ng_eiface.c,v 1.32.2.4 2006/02/14 06:21:47 ru Exp $
   */
  
  #include <sys/param.h>
--- 25,31 ----
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
!  * $FreeBSD: src/sys/netgraph/ng_eiface.c,v 1.32.2.4+ 2006/02/14 06:21:47 ru Exp $
   */
  
  #include <sys/param.h>
***************
*** 233,238 ****
--- 233,244 ----
  		 * XXX is this safe? locking?
  		 */
  		BPF_MTAP(ifp, m);
+ 
+ 		if (ifp->if_flags & IFF_MONITOR) {
+ 			ifp->if_ipackets++;
+ 			m_freem(m);
+ 			continue;
+ 		}
  
  		/*
  		 * Send packet; if hook is not connected, mbuf will get
>Release-Note:
>Audit-Trail:
>Unformatted: