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>

net/bridge/br_vlan.c

@@ -5,6 +5,7 @@
 #include <net/switchdev.h>
 
 #include "br_private.h"
+#include "br_private_tunnel.h"
 
 static inline int br_vlan_cmp(struct rhashtable_compare_arg *arg,
 			      const void *ptr)
@@ -310,6 +311,7 @@ static int __vlan_del(struct net_bridge_vlan *v)
 	}
 
 	if (masterv != v) {
+		vlan_tunnel_info_del(vg, v);
 		rhashtable_remove_fast(&vg->vlan_hash, &v->vnode,
 				       br_vlan_rht_params);
 		__vlan_del_list(v);
@@ -325,6 +327,7 @@ static void __vlan_group_free(struct net_bridge_vlan_group *vg)
 {
 	WARN_ON(!list_empty(&vg->vlan_list));
 	rhashtable_destroy(&vg->vlan_hash);
+	vlan_tunnel_deinit(vg);
 	kfree(vg);
 }
 
@@ -613,6 +616,8 @@ int br_vlan_delete(struct net_bridge *br, u16 vid)
 	br_fdb_find_delete_local(br, NULL, br->dev->dev_addr, vid);
 	br_fdb_delete_by_port(br, NULL, vid, 0);
 
+	vlan_tunnel_info_del(vg, v);
+
 	return __vlan_del(v);
 }
 
@@ -918,6 +923,9 @@ int br_vlan_init(struct net_bridge *br)
 	ret = rhashtable_init(&vg->vlan_hash, &br_vlan_rht_params);
 	if (ret)
 		goto err_rhtbl;
+	ret = vlan_tunnel_init(vg);
+	if (ret)
+		goto err_tunnel_init;
 	INIT_LIST_HEAD(&vg->vlan_list);
 	br->vlan_proto = htons(ETH_P_8021Q);
 	br->default_pvid = 1;
@@ -932,6 +940,8 @@ out:
 	return ret;
 
 err_vlan_add:
+	vlan_tunnel_deinit(vg);
+err_tunnel_init:
 	rhashtable_destroy(&vg->vlan_hash);
 err_rhtbl:
 	kfree(vg);
@@ -961,6 +971,9 @@ int nbp_vlan_init(struct net_bridge_port *p)
 	ret = rhashtable_init(&vg->vlan_hash, &br_vlan_rht_params);
 	if (ret)
 		goto err_rhtbl;
+	ret = vlan_tunnel_init(vg);
+	if (ret)
+		goto err_tunnel_init;
 	INIT_LIST_HEAD(&vg->vlan_list);
 	rcu_assign_pointer(p->vlgrp, vg);
 	if (p->br->default_pvid) {
@@ -976,8 +989,10 @@ out:
 err_vlan_add:
 	RCU_INIT_POINTER(p->vlgrp, NULL);
 	synchronize_rcu();
-	rhashtable_destroy(&vg->vlan_hash);
+	vlan_tunnel_deinit(vg);
 err_vlan_enabled:
+err_tunnel_init:
+	rhashtable_destroy(&vg->vlan_hash);
 err_rhtbl:
 	kfree(vg);