Re: [net-next PATCH 2/2] bridge: netlink dump interface at par with brctl

From: Jamal Hadi Salim <jhs@mojatatu.com>

Actually better than brctl showmacs because we can filter by bridge
port in the kernel.
The current bridge netlink interface doesnt scale when you have many
bridges each with large fdbs or even bridges with many bridge ports

For example usage look at accompanying iproute2 patch.

Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
---
  net/bridge/br_fdb.c  |   17 +++++++++---
  net/core/rtnetlink.c |   71 +++++++++++++++++++++++++++++++++++++++++---------
  2 files changed, 72 insertions(+), 16 deletions(-)

diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 48449fc..7114382 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c

@@ -694,9 +694,20 @@ int br_fdb_dump(struct sk_buff *skb,
  			if (idx < cb->args[0])
  				goto skip;

-			if (filter_dev && (!f->dst || !f->dst->dev ||
-					   f->dst->dev != filter_dev))
-				goto skip;
+			if (filter_dev && (!f->dst || f->dst->dev != filter_dev)) {
+				if (filter_dev != dev)
+					goto skip;
+				else {
+					/*
+					 * !f->dst is a speacial case for bridge
+					 * It means the MAC belongs to the bridge
+					 * Therefore need a little more filtering
+					 * we only want to dump the !f->dst case
+					 */
+					if (f->dst)
+						goto skip;
+				}
+			}

  			if (fdb_fill_info(skb, br, f,
  					  NETLINK_CB(cb->skb).portid,

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 8721f1b..2a3c225 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c

@@ -2512,26 +2512,71 @@ EXPORT_SYMBOL(ndo_dflt_fdb_dump);

  static int rtnl_fdb_dump(struct sk_buff *skb, struct netlink_callback *cb)
  {
-	int idx = 0;
-	struct net *net = sock_net(skb->sk);
  	struct net_device *dev;
+	struct nlattr *tb[IFLA_MAX+1];
+	struct net_device *bdev = NULL; /*pacify stoopid gcc*/
+	struct net_device *br_dev = NULL; /*pacify stoopid gcc*/
+	const struct net_device_ops *ops = NULL; /*pacify stoopid gcc*/
+	struct ifinfomsg *ifm = nlmsg_data(cb->nlh);
+	struct net *net = sock_net(skb->sk);
+	int brport_idx = 0;
+	int br_idx = 0;
+	int idx = 0;
+
+	if (nlmsg_parse(cb->nlh, sizeof(struct ifinfomsg), tb, IFLA_MAX,
+			ifla_policy) == 0) {
+		if (tb[IFLA_MASTER])
+			br_idx = nla_get_u32(tb[IFLA_MASTER]);
+	}
+	
+	brport_idx = ifm->ifi_index;

  	rcu_read_lock();
+	if (br_idx) {
+		br_dev = __dev_get_by_index(net, br_idx);
+		if (!br_dev) {
+			rcu_read_unlock();
+			return -ENODEV;
+		}
+		ops = br_dev->netdev_ops;
+		bdev = br_dev;
+	}
+
  	for_each_netdev_rcu(net, dev) {
-		if (dev->priv_flags & IFF_BRIDGE_PORT) {
-			struct net_device *br_dev;
-			const struct net_device_ops *ops;
-
-			br_dev = netdev_master_upper_dev_get(dev);
-			ops = br_dev->netdev_ops;
-			if (ops->ndo_fdb_dump)
-				idx = ops->ndo_fdb_dump(skb, cb, dev, NULL, idx);
+
+		if (brport_idx && (dev->ifindex != brport_idx))
+			continue;
+
+		if (!br_idx) { /* user did not specify a specific bridge */
+			if (dev->priv_flags & IFF_BRIDGE_PORT) {
+				br_dev = netdev_master_upper_dev_get(dev);
+				ops = br_dev->netdev_ops;
+				if (ops->ndo_fdb_dump)
+					idx = ops->ndo_fdb_dump(skb, cb, br_dev,
+								dev, idx);
+			}
+
+			bdev = dev;
+		} else {
+			if (dev != br_dev &&
+			    !(dev->priv_flags & IFF_BRIDGE_PORT))
+				continue;
+
+			if (br_dev != netdev_master_upper_dev_get(dev) &&
+			    !(dev->priv_flags & IFF_EBRIDGE))
+				continue;
+
+			if (dev->priv_flags & IFF_BRIDGE_PORT)
+				idx = ops->ndo_fdb_dump(skb, cb, br_dev,
+							dev, idx);
  		}

-		if (dev->netdev_ops->ndo_fdb_dump)
-			idx = dev->netdev_ops->ndo_fdb_dump(skb, cb, dev, NULL, idx);
-		else
+		if (dev->netdev_ops->ndo_fdb_dump) {
+			idx = dev->netdev_ops->ndo_fdb_dump(skb, cb, bdev, dev,
+							    idx);
+		} else {
  			idx = ndo_dflt_fdb_dump(skb, cb, dev, NULL, idx);
+		}
  	}
  	rcu_read_unlock();