make setting a vlan interfaces lladdr more likely to work

the recent vlan code sets the vlan interfaces mac address to the
parent interfaces mac address when it is brought up, and resets it
when the vlan interface is brought down.

now, if you set a mac address manually (eg, ifconfig vlanX lladdr
f0:0b:a7:ba:2b:00), vlan(4) ignores the parents mac address and
never resets its own.

to make this work, setting a custom lladdr on a vlan interface makes
the parent interface promisc so the packets wont be filtered by the
hardware interface.

setting the mac address to 00:00:00:00:00:00 resets this behavior
and makes the interface inherit the parents mac again.

issue reported by and fix tested by paul de weerd

2 files changed, 81 insertions, 36 deletions

diff --git a/sys/net/if_vlan.c b/sys/net/if_vlan.c
index 2e7ea5f1a9c..d9eaf106399 100644
--- a/sys/net/if_vlan.c
+++ b/sys/net/if_vlan.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_vlan.c,v 1.162 2016/04/15 04:34:10 dlg Exp $	*/
+/*	$OpenBSD: if_vlan.c,v 1.163 2016/04/19 23:31:32 dlg Exp $	*/
 
 /*
  * Copyright 1998 Massachusetts Institute of Technology
@@ -92,8 +92,6 @@ int	vlan_up(struct ifvlan *);
 int	vlan_parent_up(struct ifvlan *, struct ifnet *);
 int	vlan_down(struct ifvlan *);
 
-int	vlan_promisc(struct ifvlan *, int);
-
 void	vlan_ifdetach(void *);
 void	vlan_link_hook(void *);
 void	vlan_link_state(struct ifvlan *, u_char, u_int64_t);
@@ -107,6 +105,9 @@ int	vlan_multi_del(struct ifvlan *, struct ifreq *);
 void	vlan_multi_apply(struct ifvlan *, struct ifnet *, u_long);
 void	vlan_multi_free(struct ifvlan *);
 
+int	vlan_iff(struct ifvlan *);
+int	vlan_setlladdr(struct ifvlan *, struct ifreq *);
+
 int	vlan_set_compat(struct ifnet *, struct ifreq *);
 int	vlan_get_compat(struct ifnet *, struct ifreq *);
 
@@ -470,7 +471,8 @@ vlan_up(struct ifvlan *ifv)
 	/* parent is fine, let's prepare the ifv to handle packets */
 	ifp->if_hardmtu = hardmtu;
 	SET(ifp->if_flags, ifp0->if_flags & IFF_SIMPLEX);
-	if_setlladdr(ifp, LLADDR(ifp0->if_sadl));
+	if (!ISSET(ifv->ifv_flags, IFVF_LLADDR))
+		if_setlladdr(ifp, LLADDR(ifp0->if_sadl));
 
 	if (ifv->ifv_type != ETHERTYPE_VLAN) {
 		/*
@@ -522,7 +524,8 @@ leave:
 	rw_exit(&vlan_tagh_lk);
 scrub:
 	ifp->if_capabilities = 0;
-	if_setlladdr(ifp, etheranyaddr);
+	if (!ISSET(ifv->ifv_flags, IFVF_LLADDR))
+		if_setlladdr(ifp, etheranyaddr);
 	CLR(ifp->if_flags, IFF_SIMPLEX);
 	ifp->if_hardmtu = 0xffff;
 put:
@@ -564,7 +567,8 @@ vlan_down(struct ifvlan *ifv)
 	rw_exit_write(&vlan_tagh_lk);
 
 	ifp->if_capabilities = 0;
-	if_setlladdr(ifp, etheranyaddr);
+	if (!ISSET(ifv->ifv_flags, IFVF_LLADDR))
+		if_setlladdr(ifp, etheranyaddr);
 	CLR(ifp->if_flags, IFF_SIMPLEX);
 	ifp->if_hardmtu = 0xffff;
 
@@ -617,29 +621,6 @@ vlan_link_state(struct ifvlan *ifv, u_char link, uint64_t baud)
 }
 
 int
-vlan_promisc(struct ifvlan *ifv, int promisc)
-{
-	struct ifnet *ifp0;
-	int error = 0;
-
-	if ((ISSET(ifv->ifv_flags, IFVF_PROMISC) ? 1 : 0) == promisc)
-		return (0);
-
-	ifp0 = if_get(ifv->ifv_ifp0);
-	if (ifp0 != NULL) {
-		error = ifpromisc(ifp0, promisc);
-	}
-	if_put(ifp0);
-
-	if (error == 0) {
-		CLR(ifv->ifv_flags, IFVF_PROMISC);
-		SET(ifv->ifv_flags, promisc ? IFVF_PROMISC : 0);
-	}
-
-	return (error);
-}
-
-int
 vlan_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
 {
 	struct ifvlan *ifv = ifp->if_softc;
@@ -655,14 +636,11 @@ vlan_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
 		/* FALLTHROUGH */
 
 	case SIOCSIFFLAGS:
-		error = vlan_promisc(ifv,
-		    ISSET(ifp->if_flags, IFF_PROMISC) ? 1 : 0);
-		if (error != 0)
-			break;
-
 		if (ISSET(ifp->if_flags, IFF_UP)) {
 			if (!ISSET(ifp->if_flags, IFF_RUNNING))
 				error = vlan_up(ifv);
+			else
+				error = ENETRESET;
 		} else {
 			if (ISSET(ifp->if_flags, IFF_RUNNING))
 				error = vlan_down(ifv);
@@ -749,6 +727,10 @@ vlan_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
 		error = vlan_multi_del(ifv, ifr);
 		break;
 
+	case SIOCSIFLLADDR:
+		error = vlan_setlladdr(ifv, ifr);
+		break;
+
 	case SIOCSETVLAN:
 		error = vlan_set_compat(ifp, ifr);
 		break;
@@ -761,10 +743,72 @@ vlan_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
 		break;
 	}
 
+	if (error == ENETRESET) {
+		vlan_iff(ifv);
+		error = 0;
+	}
+
 	return error;
 }
 
 int
+vlan_iff(struct ifvlan *ifv)
+{
+	struct ifnet *ifp0;
+	int promisc = 0;
+	int error = 0;
+
+	if (ISSET(ifv->ifv_if.if_flags, IFF_PROMISC) ||
+	    ISSET(ifv->ifv_flags, IFVF_LLADDR))
+		promisc = IFVF_PROMISC;
+
+	if (ISSET(ifv->ifv_flags, IFVF_PROMISC) == promisc)
+		return (0);
+
+	if (ISSET(ifv->ifv_if.if_flags, IFF_RUNNING)) {
+		ifp0 = if_get(ifv->ifv_ifp0);
+		if (ifp0 != NULL)
+			error = ifpromisc(ifp0, promisc);
+		if_put(ifp0);
+	}
+
+	if (error == 0) {
+		CLR(ifv->ifv_flags, IFVF_PROMISC);
+		SET(ifv->ifv_flags, promisc);
+	}
+
+	return (error);
+}
+
+int
+vlan_setlladdr(struct ifvlan *ifv, struct ifreq *ifr)
+{
+	struct ifnet *ifp = &ifv->ifv_if;;
+	struct ifnet *ifp0;
+	int flag = IFVF_LLADDR;
+
+	/* setting the mac addr to 00:00:00:00:00:00 means reset lladdr */
+	if (memcmp(ifr->ifr_addr.sa_data, etheranyaddr, ETHER_ADDR_LEN) == 0)
+		flag = 0;
+
+	if (ISSET(ifv->ifv_flags, IFVF_LLADDR) == flag)
+		return (0);
+
+	/* if we're up and the mac is reset, inherit the parents mac */
+	if (ISSET(ifp->if_flags, IFF_RUNNING) && flag == 0) {
+		ifp0 = if_get(ifv->ifv_ifp0);
+		if (ifp0 != NULL)
+			if_setlladdr(ifp, LLADDR(ifp0->if_sadl));
+		if_put(ifp0);
+	}
+
+	CLR(ifv->ifv_flags, IFVF_LLADDR);
+	SET(ifv->ifv_flags, flag);
+
+	return (ENETRESET);
+}
+
+int
 vlan_set_vnetid(struct ifvlan *ifv, uint16_t tag)
 {
 	struct ifnet *ifp = &ifv->ifv_if;
diff --git a/sys/net/if_vlan_var.h b/sys/net/if_vlan_var.h
index ea479f57bcf..9361a9f33bd 100644
--- a/sys/net/if_vlan_var.h
+++ b/sys/net/if_vlan_var.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_vlan_var.h,v 1.35 2016/04/15 04:34:10 dlg Exp $	*/
+/*	$OpenBSD: if_vlan_var.h,v 1.36 2016/04/19 23:31:32 dlg Exp $	*/
 
 /*
  * Copyright 1998 Massachusetts Institute of Technology
@@ -81,7 +81,8 @@ struct	ifvlan {
 #define	ifv_tag		ifv_mib.ifvm_tag
 #define	ifv_prio	ifv_mib.ifvm_prio
 #define	ifv_type	ifv_mib.ifvm_type
-#define	IFVF_PROMISC	0x01
+#define	IFVF_PROMISC	0x01	/* the parent should be made promisc */
+#define	IFVF_LLADDR	0x02	/* don't inherit the parents mac */
 
 struct mbuf	*vlan_inject(struct mbuf *, uint16_t, uint16_t);
 #endif /* _KERNEL */