[PATCH net-next 2/3] net: 8021q: fix bridge binding behavior for vlan interfaces

[Sevinj Aghayeva]

Currently, when one creates a vlan interface with the bridge binding
flag disabled (using ip link add... command) and then enables the
bridge binding flag afterwards (using ip link set... command), the
second command has no effect. In other words, the vlan interface does
not follow the status of the ports in its vlan.

The root cause of this problem is as follows. The correct bridge
binding behavior depends on two flags being set: a per vlan interface
flag (VLAN_FLAG_BRIDGE_BINDING) and global per bridge flag
(BROPT_VLAN_BRIDGE_BINDING); the ip link set command calls
vlan_dev_change_flags function, which sets only the per vlan interface
flag.

The correct behavior is to set/unset per bridge flag as well,
depending on whether there are other vlan interfaces with bridge
binding flags set. The logic for this behavior is already captured in
br_vlan_upper_change function. This patch fixes the bridge binding
behavior by calling the br_vlan_upper_change function whenever the per
interface flag is changed via vlan_dev_change_flags function.

Signed-off-by: Sevinj Aghayeva <sevinj.aghayeva@xxxxxxxxx>
Reviewed-by: Stefano Brivio <sbrivio@xxxxxxxxxx>
Reviewed-by: Andy Roulin <aroulin@xxxxxxxxxx>
Reviewed-by: Roopa Prabhu <roopa@xxxxxxxxxx>
---
 net/8021q/vlan.h     |  2 +-
 net/8021q/vlan_dev.c | 21 ++++++++++++++++++---
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/net/8021q/vlan.h b/net/8021q/vlan.h
index 5eaf38875554..71947cdcfaaa 100644
--- a/net/8021q/vlan.h
+++ b/net/8021q/vlan.h
@@ -130,7 +130,7 @@ void vlan_dev_set_ingress_priority(const struct net_device *dev,
 int vlan_dev_set_egress_priority(const struct net_device *dev,
 				 u32 skb_prio, u16 vlan_prio);
 void vlan_dev_free_egress_priority(const struct net_device *dev);
-int vlan_dev_change_flags(const struct net_device *dev, u32 flag, u32 mask);
+int vlan_dev_change_flags(struct net_device *dev, u32 flag, u32 mask);
 void vlan_dev_get_realdev_name(const struct net_device *dev, char *result,
 			       size_t size);
 
diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
index 035812b0461c..93680bac60b3 100644
--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -30,6 +30,7 @@
 #include "vlan.h"
 #include "vlanproc.h"
 #include <linux/if_vlan.h>
+#include <linux/if_bridge.h>
 #include <linux/netpoll.h>
 
 /*
@@ -211,10 +212,11 @@ int vlan_dev_set_egress_priority(const struct net_device *dev,
 /* Flags are defined in the vlan_flags enum in
  * include/uapi/linux/if_vlan.h file.
  */
-int vlan_dev_change_flags(const struct net_device *dev, u32 flags, u32 mask)
+int vlan_dev_change_flags(struct net_device *dev, u32 flags, u32 mask)
 {
 	struct vlan_dev_priv *vlan = vlan_dev_priv(dev);
 	u32 old_flags = vlan->flags;
+	struct net_device *br_dev;
 
 	if (mask & ~(VLAN_FLAG_REORDER_HDR | VLAN_FLAG_GVRP |
 		     VLAN_FLAG_LOOSE_BINDING | VLAN_FLAG_MVRP |
@@ -223,19 +225,32 @@ int vlan_dev_change_flags(const struct net_device *dev, u32 flags, u32 mask)
 
 	vlan->flags = (old_flags & ~mask) | (flags & mask);
 
-	if (netif_running(dev) && (vlan->flags ^ old_flags) & VLAN_FLAG_GVRP) {
+	if (!netif_running(dev))
+		return 0;
+
+	if ((vlan->flags ^ old_flags) & VLAN_FLAG_GVRP) {
 		if (vlan->flags & VLAN_FLAG_GVRP)
 			vlan_gvrp_request_join(dev);
 		else
 			vlan_gvrp_request_leave(dev);
 	}
 
-	if (netif_running(dev) && (vlan->flags ^ old_flags) & VLAN_FLAG_MVRP) {
+	if ((vlan->flags ^ old_flags) & VLAN_FLAG_MVRP) {
 		if (vlan->flags & VLAN_FLAG_MVRP)
 			vlan_mvrp_request_join(dev);
 		else
 			vlan_mvrp_request_leave(dev);
 	}
+
+	if ((vlan->flags ^ old_flags) & VLAN_FLAG_BRIDGE_BINDING &&
+	    netif_is_bridge_port(dev)) {
+		br_dev = vlan->real_dev;
+		if (vlan->flags & VLAN_FLAG_BRIDGE_BINDING)
+			br_vlan_upper_change(br_dev, dev, true);
+		else
+			br_vlan_upper_change(br_dev, dev, false);
+	}
+
 	return 0;
 }
 
-- 
2.25.1