bridge: Implement vlan ingress/egress policy with PVID.

At ingress, any untagged traffic is assigned to the PVID.
Any tagged traffic is filtered according to membership bitmap.

At egress, if the vlan matches the PVID, the frame is sent
untagged.  Otherwise the frame is sent tagged.

Signed-off-by: Vlad Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 78 insertions, 5 deletions

diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
index f2bf5a197ea3..20057de56db0 100644
--- a/net/bridge/br_vlan.c
+++ b/net/bridge/br_vlan.c
@@ -66,12 +66,68 @@ static void __vlan_flush(struct net_port_vlans *v)
 	kfree_rcu(v, rcu);
 }
 
-/* Called under RCU */
-bool br_allowed_ingress(struct net_bridge *br, struct net_port_vlans *v,
-			struct sk_buff *skb)
+/* Strip the tag from the packet.  Will return skb with tci set 0.  */
+static struct sk_buff *br_vlan_untag(struct sk_buff *skb)
+{
+	if (skb->protocol != htons(ETH_P_8021Q)) {
+		skb->vlan_tci = 0;
+		return skb;
+	}
+
+	skb->vlan_tci = 0;
+	skb = vlan_untag(skb);
+	if (skb)
+		skb->vlan_tci = 0;
+
+	return skb;
+}
+
+struct sk_buff *br_handle_vlan(struct net_bridge *br,
+			       const struct net_port_vlans *pv,
+			       struct sk_buff *skb)
 {
 	u16 vid;
 
+	if (!br->vlan_enabled)
+		goto out;
+
+	/* At this point, we know that the frame was filtered and contains
+	 * a valid vlan id.  If the vlan id matches the pvid of current port
+	 * send untagged; otherwise, send taged.
+	 */
+	br_vlan_get_tag(skb, &vid);
+	if (vid == br_get_pvid(pv))
+		skb = br_vlan_untag(skb);
+	else {
+		/* Egress policy says "send tagged".  If output device
+		 * is the  bridge, we need to add the VLAN header
+		 * ourselves since we'll be going through the RX path.
+		 * Sending to ports puts the frame on the TX path and
+		 * we let dev_hard_start_xmit() add the header.
+		 */
+		if (skb->protocol != htons(ETH_P_8021Q) &&
+		    pv->port_idx == 0) {
+			/* vlan_put_tag expects skb->data to point to
+			 * mac header.
+			 */
+			skb_push(skb, ETH_HLEN);
+			skb = __vlan_put_tag(skb, skb->vlan_tci);
+			if (!skb)
+				goto out;
+			/* put skb->data back to where it was */
+			skb_pull(skb, ETH_HLEN);
+			skb->vlan_tci = 0;
+		}
+	}
+
+out:
+	return skb;
+}
+
+/* Called under RCU */
+bool br_allowed_ingress(struct net_bridge *br, struct net_port_vlans *v,
+			struct sk_buff *skb, u16 *vid)
+{
 	/* If VLAN filtering is disabled on the bridge, all packets are
 	 * permitted.
 	 */
@@ -84,8 +140,25 @@ bool br_allowed_ingress(struct net_bridge *br, struct net_port_vlans *v,
 	if (!v)
 		return false;
 
-	br_vlan_get_tag(skb, &vid);
-	if (test_bit(vid, v->vlan_bitmap))
+	if (br_vlan_get_tag(skb, vid)) {
+		u16 pvid = br_get_pvid(v);
+
+		/* Frame did not have a tag.  See if pvid is set
+		 * on this port.  That tells us which vlan untagged
+		 * traffic belongs to.
+		 */
+		if (pvid == VLAN_N_VID)
+			return false;
+
+		/* PVID is set on this port.  Any untagged ingress
+		 * frame is considered to belong to this vlan.
+		 */
+		__vlan_hwaccel_put_tag(skb, pvid);
+		return true;
+	}
+
+	/* Frame had a valid vlan tag.  See if vlan is allowed */
+	if (test_bit(*vid, v->vlan_bitmap))
 		return true;
 
 	return false;