On Wed, 08 Sep 1999 19:31:29 +0900 
 itojun@iijlab.net wrote:

 > 	The following patch fixes behavior for sm* ethernet interface
 > 	during promiscuous mode.  The driver loops back multicast packet
 > 	sent from itself, during promiscuous mode (which is not IFF_SIMPLEX
 > 	behavior).  This fixes IPv6 DAD behavior when you run tcpdump on
 > 	sm* interface.

It only loops back to itself when in promiscuous mode?  Wow, that's sick.

Change looks fine to me.

 > Index: smc91cxx.c
 > ===================================================================
 > RCS file: /cvsroot/kame/kame/netbsd/sys/dev/ic/smc91cxx.c,v
 > retrieving revision 1.1.1.1
 > diff -c -r1.1.1.1 smc91cxx.c
 > *** smc91cxx.c	1999/07/29 12:24:01	1.1.1.1
 > --- smc91cxx.c	1999/09/08 10:17:55
 > ***************
 > *** 928,944 ****
 >   	 * Hand the packet off to bpf listeners.  If there's a bpf listener,
 >   	 * we need to check if the packet is ours.
   	 */
 > ! 	if (ifp->if_bpf) {
 >   		bpf_mtap(ifp->if_bpf, m);
 >   
 > ! 		if ((ifp->if_flags & IFF_PROMISC) &&
 > ! 		    (eh->ether_dhost[0] & 1) == 0 &&	/* !mcast and !bcast */
 > ! 		    ether_cmp(eh->ether_dhost, LLADDR(ifp->if_sadl))) {
 >   			m_freem(m);
 >   			goto out;
 >   		}
 >   	}
 > - #endif
 >   
 >   	/*
 >   	 * Strip the ethernet header.
 > --- 928,958 ----
 >   	 * Hand the packet off to bpf listeners.  If there's a bpf listener,
 >   	 * we need to check if the packet is ours.
 >   	 */
 > ! 	if (ifp->if_bpf)
 >   		bpf_mtap(ifp->if_bpf, m);
 > + #endif
 > + 
 > + 	if ((ifp->if_flags & IFF_PROMISC) != 0) {
 > + 		/*
 > + 		 * If this is unicast and not for me, drop it.
 > + 		 */
 > + 		if ((eh->ether_dhost[0] & 1) == 0 &&	/* !mcast and !bcast */
 > + 		    ether_cmp(eh->ether_dhost, LLADDR(ifp->if_sadl)) != 0) {
 > + 			m_freem(m);
 > + 			goto out;
 > + 		}
 >   
 > ! 		/*
 > ! 		 * Make sure to behave as IFF_SIMPLEX in all cases.
 > ! 		 * Drop multicast/broadcast packet looped back from myself
 > ! 		 * (should be ensured by chipset configuration).
 > ! 		 */
 > ! 		if ((eh->ether_dhost[0] & 1) == 1 &&	/* mcast || bcast */
 > ! 		    ether_cmp(eh->ether_shost, LLADDR(ifp->if_sadl)) == 0) {
 >   			m_freem(m);
 >   			goto out;
 >   		}
 >   	}
 >   
 >   	/*
 >   	 * Strip the ethernet header.
 > 
 > ------- =_aaaaaaaaaa0--

        -- Jason R. Thorpe <thorpej@nas.nasa.gov>