bridge: add vlan info to bridge setlink and dellink notification messages

vlan add/deletes are not notified to userspace today. This patch adds
vlan info to bridge newlink/dellink notifications generated from the
bridge driver. Notifications use the RTEXT_FILTER_BRVLAN_COMPRESSED
flag to compress vlans into ranges whereever applicable.

The size calculations does not take ranges into account for
simplicity.  This has the potential for allocating a larger skb than
required.

There is an existing inconsistency with bridge NEWLINK and DELLINK
change notifications. Both generate NEWLINK notifications.  Since its
always a NEWLINK notification, this patch includes all vlans the port
belongs to in the notification. The NEWLINK and DELLINK request
messages however only include the vlans to be added and deleted.

Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_netlink.c

@@ -22,6 +22,24 @@
 #include "br_private.h"
 #include "br_private_stp.h"
 
+static size_t br_get_link_af_size(const struct net_device *dev)
+{
+	struct net_port_vlans *pv;
+
+	if (br_port_exists(dev))
+		pv = nbp_get_vlan_info(br_port_get_rtnl(dev));
+	else if (dev->priv_flags & IFF_EBRIDGE)
+		pv = br_get_vlan_info((struct net_bridge *)netdev_priv(dev));
+	else
+		return 0;
+
+	if (!pv)
+		return 0;
+
+	/* Each VLAN is returned in bridge_vlan_info along with flags */
+	return pv->num_vlans * nla_total_size(sizeof(struct bridge_vlan_info));
+}
+
 static inline size_t br_port_info_size(void)
 {
 	return nla_total_size(1)	/* IFLA_BRPORT_STATE  */
@@ -36,7 +54,7 @@ static inline size_t br_port_info_size(void)
 		+ 0;
 }
 
-static inline size_t br_nlmsg_size(void)
+static inline size_t br_nlmsg_size(struct net_device *dev)
 {
 	return NLMSG_ALIGN(sizeof(struct ifinfomsg))
 		+ nla_total_size(IFNAMSIZ) /* IFLA_IFNAME */
@@ -45,7 +63,8 @@ static inline size_t br_nlmsg_size(void)
 		+ nla_total_size(4) /* IFLA_MTU */
 		+ nla_total_size(4) /* IFLA_LINK */
 		+ nla_total_size(1) /* IFLA_OPERSTATE */
-		+ nla_total_size(br_port_info_size()); /* IFLA_PROTINFO */
+		+ nla_total_size(br_port_info_size()) /* IFLA_PROTINFO */
+		+ nla_total_size(br_get_link_af_size(dev)); /* IFLA_AF_SPEC */
 }
 
 static int br_port_fill_attrs(struct sk_buff *skb,
@@ -288,11 +307,12 @@ void br_ifinfo_notify(int event, struct net_bridge_port *port)
 	br_debug(port->br, "port %u(%s) event %d\n",
 		 (unsigned int)port->port_no, port->dev->name, event);
 
-	skb = nlmsg_new(br_nlmsg_size(), GFP_ATOMIC);
+	skb = nlmsg_new(br_nlmsg_size(port->dev), GFP_ATOMIC);
 	if (skb == NULL)
 		goto errout;
 
-	err = br_fill_ifinfo(skb, port, 0, 0, event, 0, 0, port->dev);
+	err = br_fill_ifinfo(skb, port, 0, 0, event, 0,
+			     RTEXT_FILTER_BRVLAN_COMPRESSED, port->dev);
 	if (err < 0) {
 		/* -EMSGSIZE implies BUG in br_nlmsg_size() */
 		WARN_ON(err == -EMSGSIZE);
@@ -703,24 +723,6 @@ static int br_fill_info(struct sk_buff *skb, const struct net_device *brdev)
 	return 0;
 }
 
-static size_t br_get_link_af_size(const struct net_device *dev)
-{
-	struct net_port_vlans *pv;
-
-	if (br_port_exists(dev))
-		pv = nbp_get_vlan_info(br_port_get_rtnl(dev));
-	else if (dev->priv_flags & IFF_EBRIDGE)
-		pv = br_get_vlan_info((struct net_bridge *)netdev_priv(dev));
-	else
-		return 0;
-
-	if (!pv)
-		return 0;
-
-	/* Each VLAN is returned in bridge_vlan_info along with flags */
-	return pv->num_vlans * nla_total_size(sizeof(struct bridge_vlan_info));
-}
-
 static struct rtnl_af_ops br_af_ops __read_mostly = {
 	.family			= AF_BRIDGE,
 	.get_link_af_size	= br_get_link_af_size,