net: vlan: add 802.1ad support

Add support for 802.1ad VLAN devices. This mainly consists of checking for
ETH_P_8021AD in addition to ETH_P_8021Q in a couple of places and check
offloading capabilities based on the used protocol.

Configuration is done using "ip link":

# ip link add link eth0 eth0.1000 \
	type vlan proto 802.1ad id 1000
# ip link add link eth0.1000 eth0.1000.1000 \
	type vlan proto 802.1q id 1000

52:54:00:12:34:56 > 92:b1:54:28:e4:8c, ethertype 802.1Q (0x8100), length 106: vlan 1000, p 0, ethertype 802.1Q, vlan 1000, p 0, ethertype IPv4, (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto ICMP (1), length 84)
    20.1.0.2 > 20.1.0.1: ICMP echo request, id 3003, seq 8, length 64
92:b1:54:28:e4:8c > 52:54:00:12:34:56, ethertype 802.1Q-QinQ (0x88a8), length 106: vlan 1000, p 0, ethertype 802.1Q, vlan 1000, p 0, ethertype IPv4, (tos 0x0, ttl 64, id 47944, offset 0, flags [none], proto ICMP (1), length 84)
    20.1.0.1 > 20.1.0.2: ICMP echo reply, id 3003, seq 8, length 64

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/8021q/vlan_netlink.c b/net/8021q/vlan_netlink.c
index a1a956a..3091297 100644
--- a/net/8021q/vlan_netlink.c
+++ b/net/8021q/vlan_netlink.c
@@ -23,6 +23,7 @@
 	[IFLA_VLAN_FLAGS]	= { .len = sizeof(struct ifla_vlan_flags) },
 	[IFLA_VLAN_EGRESS_QOS]	= { .type = NLA_NESTED },
 	[IFLA_VLAN_INGRESS_QOS] = { .type = NLA_NESTED },
+	[IFLA_VLAN_PROTOCOL]	= { .type = NLA_U16 },
 };
 
 static const struct nla_policy vlan_map_policy[IFLA_VLAN_QOS_MAX + 1] = {
@@ -53,6 +54,16 @@
 	if (!data)
 		return -EINVAL;
 
+	if (data[IFLA_VLAN_PROTOCOL]) {
+		switch (nla_get_be16(data[IFLA_VLAN_PROTOCOL])) {
+		case __constant_htons(ETH_P_8021Q):
+		case __constant_htons(ETH_P_8021AD):
+			break;
+		default:
+			return -EPROTONOSUPPORT;
+		}
+	}
+
 	if (data[IFLA_VLAN_ID]) {
 		id = nla_get_u16(data[IFLA_VLAN_ID]);
 		if (id >= VLAN_VID_MASK)
@@ -107,6 +118,7 @@
 {
 	struct vlan_dev_priv *vlan = vlan_dev_priv(dev);
 	struct net_device *real_dev;
+	__be16 proto;
 	int err;
 
 	if (!data[IFLA_VLAN_ID])
@@ -118,7 +130,12 @@
 	if (!real_dev)
 		return -ENODEV;
 
-	vlan->vlan_proto = htons(ETH_P_8021Q);
+	if (data[IFLA_VLAN_PROTOCOL])
+		proto = nla_get_be16(data[IFLA_VLAN_PROTOCOL]);
+	else
+		proto = htons(ETH_P_8021Q);
+
+	vlan->vlan_proto = proto;
 	vlan->vlan_id	 = nla_get_u16(data[IFLA_VLAN_ID]);
 	vlan->real_dev	 = real_dev;
 	vlan->flags	 = VLAN_FLAG_REORDER_HDR;
@@ -152,7 +169,8 @@
 {
 	struct vlan_dev_priv *vlan = vlan_dev_priv(dev);
 
-	return nla_total_size(2) +	/* IFLA_VLAN_ID */
+	return nla_total_size(2) +	/* IFLA_VLAN_PROTOCOL */
+	       nla_total_size(2) +	/* IFLA_VLAN_ID */
 	       sizeof(struct ifla_vlan_flags) + /* IFLA_VLAN_FLAGS */
 	       vlan_qos_map_size(vlan->nr_ingress_mappings) +
 	       vlan_qos_map_size(vlan->nr_egress_mappings);
@@ -167,7 +185,8 @@
 	struct nlattr *nest;
 	unsigned int i;
 
-	if (nla_put_u16(skb, IFLA_VLAN_ID, vlan_dev_priv(dev)->vlan_id))
+	if (nla_put_be16(skb, IFLA_VLAN_PROTOCOL, vlan->vlan_proto) ||
+	    nla_put_u16(skb, IFLA_VLAN_ID, vlan->vlan_id))
 		goto nla_put_failure;
 	if (vlan->flags) {
 		f.flags = vlan->flags;