Merge branch 'net-dsa-b53-Configure-VLANs-while-not-filtering'

Florian Fainelli says:

====================
net: dsa: b53: Configure VLANs while not filtering

These two patches allow the b53 driver which always configures its CPU
port as egress tagged to behave correctly with VLANs being always
configured whenever a port is added to a bridge.

Vladimir provides a patch that aligns the bridge with vlan_filtering=0
receive path to behave the same as vlan_filtering=1. Per discussion with
Nikolay, this behavior is deemed to be too DSA specific to be done in
the bridge proper.

This is a preliminary series for Vladimir to make
configure_vlan_while_filtering the default behavior for all DSA drivers
in the future.

Thanks!

Changes in v3:

- added Vladimir's Acked-by tag to patch #2
- removed unnecessary if_vlan.h inclusion in patch #2
- reworded commit message to be accurate with the code changes

Changes in v2:

- moved the call to dsa_untag_bridge_pvid() into net/dsa/tag_brcm.c
  since we have a single user for now
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 79 insertions, 2 deletions

diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index 2da656d984ef..0348dbab4131 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -7,6 +7,7 @@
 #ifndef __DSA_PRIV_H
 #define __DSA_PRIV_H
 
+#include <linux/if_bridge.h>
 #include <linux/phy.h>
 #include <linux/netdevice.h>
 #include <linux/netpoll.h>
@@ -194,6 +195,71 @@ dsa_slave_to_master(const struct net_device *dev)
 	return dp->cpu_dp->master;
 }
 
+/* If under a bridge with vlan_filtering=0, make sure to send pvid-tagged
+ * frames as untagged, since the bridge will not untag them.
+ */
+static inline struct sk_buff *dsa_untag_bridge_pvid(struct sk_buff *skb)
+{
+	struct dsa_port *dp = dsa_slave_to_port(skb->dev);
+	struct vlan_ethhdr *hdr = vlan_eth_hdr(skb);
+	struct net_device *br = dp->bridge_dev;
+	struct net_device *dev = skb->dev;
+	struct net_device *upper_dev;
+	struct list_head *iter;
+	u16 vid, pvid, proto;
+	int err;
+
+	if (!br || br_vlan_enabled(br))
+		return skb;
+
+	err = br_vlan_get_proto(br, &proto);
+	if (err)
+		return skb;
+
+	/* Move VLAN tag from data to hwaccel */
+	if (!skb_vlan_tag_present(skb) && hdr->h_vlan_proto == htons(proto)) {
+		skb = skb_vlan_untag(skb);
+		if (!skb)
+			return NULL;
+	}
+
+	if (!skb_vlan_tag_present(skb))
+		return skb;
+
+	vid = skb_vlan_tag_get_id(skb);
+
+	/* We already run under an RCU read-side critical section since
+	 * we are called from netif_receive_skb_list_internal().
+	 */
+	err = br_vlan_get_pvid_rcu(dev, &pvid);
+	if (err)
+		return skb;
+
+	if (vid != pvid)
+		return skb;
+
+	/* The sad part about attempting to untag from DSA is that we
+	 * don't know, unless we check, if the skb will end up in
+	 * the bridge's data path - br_allowed_ingress() - or not.
+	 * For example, there might be an 8021q upper for the
+	 * default_pvid of the bridge, which will steal VLAN-tagged traffic
+	 * from the bridge's data path. This is a configuration that DSA
+	 * supports because vlan_filtering is 0. In that case, we should
+	 * definitely keep the tag, to make sure it keeps working.
+	 */
+	netdev_for_each_upper_dev_rcu(dev, upper_dev, iter) {
+		if (!is_vlan_dev(upper_dev))
+			continue;
+
+		if (vid == vlan_dev_vlan_id(upper_dev))
+			return skb;
+	}
+
+	__vlan_hwaccel_clear_tag(skb);
+
+	return skb;
+}
+
 /* switch.c */
 int dsa_switch_register_notifier(struct dsa_switch *ds);
 void dsa_switch_unregister_notifier(struct dsa_switch *ds);
diff --git a/net/dsa/tag_brcm.c b/net/dsa/tag_brcm.c
index cc8512b5f9e2..1dab212a294f 100644
--- a/net/dsa/tag_brcm.c
+++ b/net/dsa/tag_brcm.c
@@ -140,6 +140,11 @@ static struct sk_buff *brcm_tag_rcv_ll(struct sk_buff *skb,
 	/* Remove Broadcom tag and update checksum */
 	skb_pull_rcsum(skb, BRCM_TAG_LEN);
 
+	/* Set the MAC header to where it should point for
+	 * dsa_untag_bridge_pvid() to parse the correct VLAN header.
+	 */
+	skb_set_mac_header(skb, -ETH_HLEN);
+
 	skb->offload_fwd_mark = 1;
 
 	return skb;
@@ -191,7 +196,7 @@ static struct sk_buff *brcm_tag_rcv(struct sk_buff *skb, struct net_device *dev,
 		nskb->data - ETH_HLEN - BRCM_TAG_LEN,
 		2 * ETH_ALEN);
 
-	return nskb;
+	return dsa_untag_bridge_pvid(nskb);
 }
 
 static const struct dsa_device_ops brcm_netdev_ops = {
@@ -219,8 +224,14 @@ static struct sk_buff *brcm_tag_rcv_prepend(struct sk_buff *skb,
 					    struct net_device *dev,
 					    struct packet_type *pt)
 {
+	struct sk_buff *nskb;
+
 	/* tag is prepended to the packet */
-	return brcm_tag_rcv_ll(skb, dev, pt, ETH_HLEN);
+	nskb = brcm_tag_rcv_ll(skb, dev, pt, ETH_HLEN);
+	if (!nskb)
+		return nskb;
+
+	return dsa_untag_bridge_pvid(nskb);
 }
 
 static const struct dsa_device_ops brcm_prepend_netdev_ops = {