# 
# Patch from FreeBSD modified for OpenBSD 3.2 that should
# allow changing of link-layer address for a given
# interface (eg. MAC address on Ethernet).
# Adapted by Michal Ludvig <michal@logix.cz>
# See http://www.logix.cz/michal/devel/openbsd-lladdr/ for more info.
# 
Index: sys/sockio.h
===================================================================
RCS file: /cvs/src/sys/sys/sockio.h,v
retrieving revision 1.20
diff -u -p -r1.20 sockio.h
--- sys/sockio.h	15 Dec 2001 08:40:56 -0000	1.20
+++ sys/sockio.h	14 Nov 2002 21:09:02 -0000
@@ -92,6 +92,8 @@
 #define	SIOCSIFGENERIC	 _IOW('i', 57, struct ifreq)	/* generic IF set op */
 #define	SIOCGIFGENERIC	_IOWR('i', 58, struct ifreq)	/* generic IF get op */
 
+#define	SIOCSIFLLADDR    _IOW('i', 60, struct ifreq)	/* set link level addr */
+
 #define SIOCSIFPHYADDR   _IOW('i', 70, struct ifaliasreq) /* set gif addres */
 #define	SIOCGIFPSRCADDR	_IOWR('i', 71, struct ifreq)	/* get gif psrc addr */
 #define	SIOCGIFPDSTADDR	_IOWR('i', 72, struct ifreq)	/* get gif pdst addr */
Index: net/if.c
===================================================================
RCS file: /cvs/src/sys/net/if.c,v
retrieving revision 1.64
diff -u -p -r1.64 if.c
--- net/if.c	11 Sep 2002 05:38:47 -0000	1.64
+++ net/if.c	14 Nov 2002 21:09:02 -0000
@@ -80,6 +80,7 @@
 #include <sys/domain.h>
 
 #include <net/if.h>
+#include <net/if_arp.h>
 #include <net/if_dl.h>
 #include <net/route.h>
 
@@ -823,6 +824,8 @@ ifioctl(so, cmd, data, p)
 {
 	register struct ifnet *ifp;
 	register struct ifreq *ifr;
+	register struct ifaddr *ifa;
+	struct sockaddr_dl *sdl;
 	int error = 0;
 	short oif_flags;
 
@@ -923,6 +926,33 @@ ifioctl(so, cmd, data, p)
 			return (EOPNOTSUPP);
 		error = (*ifp->if_ioctl)(ifp, cmd, data);
 		break;
+
+	case SIOCSIFLLADDR:
+		if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
+			return (error);
+		ifa = ifnet_addrs[ifp->if_index];
+		if (ifa == NULL)
+			return(EINVAL);
+		sdl = (struct sockaddr_dl *)ifa->ifa_addr;
+		if (sdl == NULL)
+			return(EINVAL);
+		bcopy(ifr->ifr_addr.sa_data,
+		    ((struct arpcom *)ifp->if_softc)->ac_enaddr,
+		    ifr->ifr_addr.sa_len);
+		bcopy(ifr->ifr_addr.sa_data, LLADDR(sdl),
+		    ifr->ifr_addr.sa_len);
+		/*
+		 * If the interface is already up, we need
+		 * to re-init it in order to reprogram its
+		 * address filter.
+		 */
+		if (ifp->if_flags & IFF_UP) {
+			ifp->if_flags &= ~IFF_UP;
+			(*ifp->if_ioctl)(ifp, SIOCSIFFLAGS, NULL);
+			ifp->if_flags |= IFF_UP;
+			(*ifp->if_ioctl)(ifp, SIOCSIFFLAGS, NULL);
+		}
+		return(0);
 
 	default:
 		if (so->so_proto == 0)