ipv6: addrconf: fix 48 bit 6lowpan autoconfiguration

This patch adds support for 48 bit 6LoWPAN address length
autoconfiguration which is the case for BTLE 6LoWPAN.
Signed-off-by: NAlexander Aring <aar@pengutronix.de>
Signed-off-by: NLuiz Augusto von Dentz <luiz.von.dentz@intel.com>
Reviewed-by: NStefan Schmidt <stefan@osg.samsung.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

net/ipv6/addrconf.c

@@ -2073,12 +2073,19 @@ static void addrconf_leave_anycast(struct inet6_ifaddr *ifp)
 	__ipv6_dev_ac_dec(ifp->idev, &addr);
 }
 
-static int addrconf_ifid_eui64(u8 *eui, struct net_device *dev)
+static int addrconf_ifid_6lowpan(u8 *eui, struct net_device *dev)
 {
-	if (dev->addr_len != EUI64_ADDR_LEN)
+	switch (dev->addr_len) {
+	case ETH_ALEN:
+		return addrconf_ifid_eui48(eui, dev);
+	case EUI64_ADDR_LEN:
+		memcpy(eui, dev->dev_addr, EUI64_ADDR_LEN);
+		eui[0] ^= 2;
+		break;
+	default:
 		return -1;
-	memcpy(eui, dev->dev_addr, EUI64_ADDR_LEN);
-	eui[0] ^= 2;
+	}
+
 	return 0;
 }
 
@@ -2170,7 +2177,7 @@ static int ipv6_generate_eui64(u8 *eui, struct net_device *dev)
 	case ARPHRD_TUNNEL:
 		return addrconf_ifid_gre(eui, dev);
 	case ARPHRD_6LOWPAN:
-		return addrconf_ifid_eui64(eui, dev);
+		return addrconf_ifid_6lowpan(eui, dev);
 	case ARPHRD_IEEE1394:
 		return addrconf_ifid_ieee1394(eui, dev);
 	case ARPHRD_TUNNEL6: