vlan(4) interfaces have wrong interface type in sockaddr_dl address

[John Baldwin]

On Tuesday, August 03, 2010 10:29:11 am John Baldwin wrote:
> Currently vlan(4) interfaces have an interface type of IFT_ETHER instead of 
> IFT_L2VLAN in the sockaddr_dl that is returned by getifaddrs(3).  If you do a 
> route lookup for a route that goes across a vlan then the sockaddr_dl 
> generated for the routing message will specify IFT_L2VLAN (you can see it as 
> 'arp -a' shows [vlan] instead of [ethernet] for those routes).  However, the 
> address returned via getifaddrs(3) has a type of IFT_ETHER.  I think this is a 
> bug of omission in that the vlan attach code needs to update the sockaddr_dl 
> that is initialized in ether_ifattach().  This patch does that and fixes 
> getifaddrs(3).  Any objections?

A few places in userland also need fixing to catch up to this I think.  I did
not patch getnameinfo(3) in libc since it explicitly claims in the comments
that IFT_L2VLAN interfaces have a zero-length address (even though this claim
is false in practice).  Updated patch:

Index: sys/net/if_vlan.c
===================================================================
--- sys/net/if_vlan.c	(revision 211312)
+++ sys/net/if_vlan.c	(working copy)
@@ -640,6 +640,8 @@
 	struct ifvlan *ifv;
 	struct ifnet *ifp;
 	struct ifnet *p;
+	struct ifaddr *ifa;
+	struct sockaddr_dl *sdl;
 	struct vlanreq vlr;
 	static const u_char eaddr[ETHER_ADDR_LEN];	/* 00:00:00:00:00:00 */
 
@@ -738,6 +740,9 @@
 	ifp->if_baudrate = 0;
 	ifp->if_type = IFT_L2VLAN;
 	ifp->if_hdrlen = ETHER_VLAN_ENCAP_LEN;
+	ifa = ifp->if_addr;
+	sdl = (struct sockaddr_dl *)ifa->ifa_addr;
+	sdl->sdl_type = IFT_L2VLAN;
 
 	if (ethertag) {
 		error = vlan_config(ifv, p, tag);
Index: sbin/ifconfig/af_link.c
===================================================================
--- sbin/ifconfig/af_link.c	(revision 211312)
+++ sbin/ifconfig/af_link.c	(working copy)
@@ -58,7 +58,9 @@
 	struct sockaddr_dl *sdl = (struct sockaddr_dl *) ifa->ifa_addr;
 
 	if (sdl != NULL && sdl->sdl_alen > 0) {
-		if (sdl->sdl_type == IFT_ETHER &&
+		if ((sdl->sdl_type == IFT_ETHER ||
+		    sdl->sdl_type == IFT_L2VLAN ||
+		    sdl->sdl_type == IFT_BRIDGE) &&
 		    sdl->sdl_alen == ETHER_ADDR_LEN)
 			printf("\tether %s\n",
 			    ether_ntoa((struct ether_addr *)LLADDR(sdl)));
Index: usr.sbin/ndp/ndp.c
===================================================================
--- usr.sbin/ndp/ndp.c	(revision 211312)
+++ usr.sbin/ndp/ndp.c	(working copy)
@@ -433,6 +433,7 @@
 			switch (sdl->sdl_type) {
 			case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023:
 			case IFT_ISO88024: case IFT_ISO88025:
+			case IFT_L2VLAN: case IFT_BRIDGE:
 				goto overwrite;
 			}
 		}
Index: usr.sbin/ppp/ipv6cp.c
===================================================================
--- usr.sbin/ppp/ipv6cp.c	(revision 211312)
+++ usr.sbin/ppp/ipv6cp.c	(working copy)
@@ -148,6 +148,7 @@
     switch(sdl->sdl_type) {
     case IFT_ETHER:
     case IFT_FDDI:
+    case IFT_L2VLAN:
       /* XXX need more cases? */
       break;
     default:

-- 
John Baldwin