bridge: add new BR_NEIGH_SUPPRESS port flag to suppress arp and nd flood

This patch adds a new bridge port flag BR_NEIGH_SUPPRESS to
suppress arp and nd flood on bridge ports. It implements
rfc7432, section 10.
https://tools.ietf.org/html/rfc7432#section-10
for ethernet VPN deployments. It is similar to the existing
BR_PROXYARP* flags but has a few semantic differences to conform
to EVPN standard. Unlike the existing flags, this new flag suppresses
flood of all neigh discovery packets (arp and nd) to tunnel ports.
Supports both vlan filtering and non-vlan filtering bridges.

In case of EVPN, it is mainly used to avoid flooding
of arp and nd packets to tunnel ports like vxlan.

This patch adds netlink and sysfs support to set this bridge port
flag.

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

1 files changed, 32 insertions, 0 deletions

diff --git a/net/bridge/br_arp_nd_proxy.c b/net/bridge/br_arp_nd_proxy.c
new file mode 100644
index 000000000000..f889ad5f0048
--- /dev/null
+++ b/net/bridge/br_arp_nd_proxy.c
@@ -0,0 +1,32 @@
+/*
+ *  Handle bridge arp/nd proxy/suppress
+ *
+ *  Copyright (C) 2017 Cumulus Networks
+ *  Copyright (c) 2017 Roopa Prabhu <roopa@cumulusnetworks.com>
+ *
+ *  Authors:
+ *	Roopa Prabhu <roopa@cumulusnetworks.com>
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version
+ *  2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include "br_private.h"
+
+void br_recalculate_neigh_suppress_enabled(struct net_bridge *br)
+{
+	struct net_bridge_port *p;
+	bool neigh_suppress = false;
+
+	list_for_each_entry(p, &br->port_list, list) {
+		if (p->flags & BR_NEIGH_SUPPRESS) {
+			neigh_suppress = true;
+			break;
+		}
+	}
+
+	br->neigh_suppress_enabled = neigh_suppress;
+}