bridge: per vlan dst_metadata netlink support

This patch adds support to attach per vlan tunnel info dst
metadata. This enables bridge driver to map vlan to tunnel_info
at ingress and egress. It uses the kernel dst_metadata infrastructure.

The initial use case is vlan to vni bridging, but the api is generic
to extend to any tunnel_info in the future:
    - Uapi to configure/unconfigure/dump per vlan tunnel data
    - netlink functions to configure vlan and tunnel_info mapping
    - Introduces bridge port flag BR_LWT_VLAN to enable attach/detach
    dst_metadata to bridged packets on ports. off by default.
    - changes to existing code is mainly refactor some existing vlan
    handling netlink code + hooks for new vlan tunnel code
    - I have kept the vlan tunnel code isolated in separate files.
    - most of the netlink vlan tunnel code is handling of vlan-tunid
    ranges (follows the vlan range handling code). To conserve space
    vlan-tunid by default are always dumped in ranges if applicable.

Use case:
example use for this is a vxlan bridging gateway or vtep
which maps vlans to vn-segments (or vnis).

iproute2 example (patched and pruned iproute2 output to just show
relevant fdb entries):
example shows same host mac learnt on two vni's and
vlan 100 maps to vni 1000, vlan 101 maps to vni 1001

before (netdev per vni):
$bridge fdb show | grep "00:02:00:00:00:03"
00:02:00:00:00:03 dev vxlan1001 vlan 101 master bridge
00:02:00:00:00:03 dev vxlan1001 dst 12.0.0.8 self
00:02:00:00:00:03 dev vxlan1000 vlan 100 master bridge
00:02:00:00:00:03 dev vxlan1000 dst 12.0.0.8 self

after this patch with collect metdata in bridged mode (single netdev):
$bridge fdb show | grep "00:02:00:00:00:03"
00:02:00:00:00:03 dev vxlan0 vlan 101 master bridge
00:02:00:00:00:03 dev vxlan0 src_vni 1001 dst 12.0.0.8 self
00:02:00:00:00:03 dev vxlan0 vlan 100 master bridge
00:02:00:00:00:03 dev vxlan0 src_vni 1000 dst 12.0.0.8 self

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

1 files changed, 10 insertions, 0 deletions

diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 0b82a227fc34..61de90f28afa 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -91,6 +91,11 @@ struct br_vlan_stats {
 	struct u64_stats_sync syncp;
 };
 
+struct br_tunnel_info {
+	__be64			tunnel_id;
+	struct metadata_dst	*tunnel_dst;
+};
+
 /**
  * struct net_bridge_vlan - per-vlan entry
  *
@@ -113,6 +118,7 @@ struct br_vlan_stats {
  */
 struct net_bridge_vlan {
 	struct rhash_head		vnode;
+	struct rhash_head		tnode;
 	u16				vid;
 	u16				flags;
 	struct br_vlan_stats __percpu	*stats;
@@ -124,6 +130,9 @@ struct net_bridge_vlan {
 		atomic_t		refcnt;
 		struct net_bridge_vlan	*brvlan;
 	};
+
+	struct br_tunnel_info		tinfo;
+
 	struct list_head		vlist;
 
 	struct rcu_head			rcu;
@@ -145,6 +154,7 @@ struct net_bridge_vlan {
  */
 struct net_bridge_vlan_group {
 	struct rhashtable		vlan_hash;
+	struct rhashtable		tunnel_hash;
 	struct list_head		vlan_list;
 	u16				num_vlans;
 	u16				pvid;