Linux Ethernet Bridging - Jul 2015 - [Bridge] [PATCH net-next] bridge: mdb: add vlan support for user entries

Until now all user mdb entries were added in vlan 0, this patch adds
support to allow the user to specify the vlan for the entry.
About the uapi change a hole in struct br_mdb_entry is used so the size
and offsets are kept the same (verified with pahole and tested with older
iproute2).

Example:
$ bridge mdb
dev br0 port eth1 grp 239.0.0.1 permanent vlan 2000
dev br0 port eth1 grp 239.0.0.1 permanent vlan 200
dev br0 port eth1 grp 239.0.0.1 permanent

Signed-off-by: Nikolay Aleksandrov <nikolay at cumulusnetworks.com>
---
note: an iproute2 patch will follow if this one is accepted

 include/uapi/linux/if_bridge.h | 1 +
 net/bridge/br_mdb.c            | 6 ++++++
 2 files changed, 7 insertions(+)

diff --git a/include/uapi/linux/if_bridge.h b/include/uapi/linux/if_bridge.h
index eaaea6208b42..3635b7797508 100644
--- a/include/uapi/linux/if_bridge.h
+++ b/include/uapi/linux/if_bridge.h
@@ -182,6 +182,7 @@ struct br_mdb_entry {
 #define MDB_TEMPORARY 0
 #define MDB_PERMANENT 1
 	__u8 state;
+	__u16 vid;
 	struct {
 		union {
 			__be32	ip4;
diff --git a/net/bridge/br_mdb.c b/net/bridge/br_mdb.c
index 1fb7d076f15c..a8d0e93d43f2 100644
--- a/net/bridge/br_mdb.c
+++ b/net/bridge/br_mdb.c
@@ -85,6 +85,7 @@ static int br_mdb_fill_info(struct sk_buff *skb, struct
netlink_callback *cb,
 					memset(&e, 0, sizeof(e));
 					e.ifindex = port->dev->ifindex;
 					e.state = p->state;
+					e.vid = p->addr.vid;
 					if (p->addr.proto == htons(ETH_P_IP))
 						e.addr.u.ip4 = p->addr.u.ip4;
 #if IS_ENABLED(CONFIG_IPV6)
@@ -242,6 +243,7 @@ void br_mdb_notify(struct net_device *dev, struct
net_bridge_port *port,
 	entry.addr.u.ip6 = group->u.ip6;
 #endif
 	entry.state = state;
+	entry.vid = group->vid;
 	__br_mdb_notify(dev, &entry, type);
 }
 
@@ -264,6 +266,8 @@ static bool is_valid_mdb_entry(struct br_mdb_entry *entry)
 		return false;
 	if (entry->state != MDB_PERMANENT && entry->state !=
MDB_TEMPORARY)
 		return false;
+	if (entry->vid >= VLAN_VID_MASK)
+		return false;
 
 	return true;
 }
@@ -372,6 +376,7 @@ static int __br_mdb_add(struct net *net, struct net_bridge
*br,
 	if (!p || p->br != br || p->state == BR_STATE_DISABLED)
 		return -EINVAL;
 
+	ip.vid = entry->vid;
 	ip.proto = entry->addr.proto;
 	if (ip.proto == htons(ETH_P_IP))
 		ip.u.ip4 = entry->addr.u.ip4;
@@ -418,6 +423,7 @@ static int __br_mdb_del(struct net_bridge *br, struct
br_mdb_entry *entry)
 	if (!netif_running(br->dev) || br->multicast_disabled)
 		return -EINVAL;
 
+	ip.vid = entry->vid;
 	ip.proto = entry->addr.proto;
 	if (ip.proto == htons(ETH_P_IP)) {
 		if (timer_pending(&br->ip4_other_query.timer))
-- 
1.9.1

From: Nikolay Aleksandrov <nikolay at cumulusnetworks.com>
Date: Fri, 10 Jul 2015 08:02:08 -0700
> Until now all user mdb entries were added in vlan 0, this patch adds
> support to allow the user to specify the vlan for the entry.
> About the uapi change a hole in struct br_mdb_entry is used so the size
> and offsets are kept the same (verified with pahole and tested with older
> iproute2).
> 
> Example:
> $ bridge mdb
> dev br0 port eth1 grp 239.0.0.1 permanent vlan 2000
> dev br0 port eth1 grp 239.0.0.1 permanent vlan 200
> dev br0 port eth1 grp 239.0.0.1 permanent
> 
> Signed-off-by: Nikolay Aleksandrov <nikolay at cumulusnetworks.com>
This looks ok, applied thanks Nikolay.

On Fri, 10 Jul 2015 08:02:08 -0700
Nikolay Aleksandrov <nikolay at cumulusnetworks.com> wrote:
> diff --git a/include/uapi/linux/if_bridge.h
b/include/uapi/linux/if_bridge.h
> index eaaea6208b42..3635b7797508 100644
> --- a/include/uapi/linux/if_bridge.h
> +++ b/include/uapi/linux/if_bridge.h
> @@ -182,6 +182,7 @@ struct br_mdb_entry {
>  #define MDB_TEMPORARY 0
>  #define MDB_PERMANENT 1
>  	__u8 state;
> +	__u16 vid;
>  	struct {
>  		union {
>  			__be32	ip4;
You added a new field into an unused hole in a data
structure shared as part of API with user space.

This seems like it might break when newer iproute
is run on older kernels. The vid would always be 0
on show and ignored when adding entries.