kernel: add hardware offload patch for flow tables support

Supports offloading through VLAN, bridge and PPPoE devices as well Signed-off-by: Felix Fietkau <nbd@nbd.name>
2024-12-24 15:56:49 +00:00 · 2018-03-12 20:51:55 +01:00 · 2018-03-12 20:51:55 +01:00 · 11a3d27043
commit 11a3d27043
parent f8dbafb234
7 changed files with 1143 additions and 2 deletions
--- a/package/kernel/linux/modules/netfilter.mk
+++ b/package/kernel/linux/modules/netfilter.mk
@ -149,8 +149,9 @@ define KernelPackage/nf-flow
 	CONFIG_NF_FLOW_TABLE_HW
  DEPENDS:=+kmod-nf-conntrack @!LINUX_3_18 @!LINUX_4_4 @!LINUX_4_9
  FILES:= \
-	$(LINUX_DIR)/net/netfilter/nf_flow_table.ko
-  AUTOLOAD:=$(call AutoProbe,nf_flow_table)
+	$(LINUX_DIR)/net/netfilter/nf_flow_table.ko \
+	$(LINUX_DIR)/net/netfilter/nf_flow_table_hw.ko
+  AUTOLOAD:=$(call AutoProbe,nf_flow_table nf_flow_table_hw)
 endef

 $(eval $(call KernelPackage,nf-flow))
--- a/target/linux/generic/pending-4.14/640-netfilter-nf_flow_table-add-hardware-offload-support.patch
+++ b/target/linux/generic/pending-4.14/640-netfilter-nf_flow_table-add-hardware-offload-support.patch
@ -0,0 +1,580 @@
+From: Pablo Neira Ayuso <pablo@netfilter.org>
+Date: Thu, 11 Jan 2018 16:32:00 +0100
+Subject: [PATCH] netfilter: nf_flow_table: add hardware offload support
+
+This patch adds the infrastructure to offload flows to hardware, in case
+the nic/switch comes with built-in flow tables capabilities.
+
+If the hardware comes with no hardware flow tables or they have
+limitations in terms of features, the existing infrastructure falls back
+to the software flow table implementation.
+
+The software flow table garbage collector skips entries that resides in
+the hardware, so the hardware will be responsible for releasing this
+flow table entry too via flow_offload_dead().
+
+Hardware configuration, either to add or to delete entries, is done from
+the hardware offload workqueue, to ensure this is done from user context
+given that we may sleep when grabbing the mdio mutex.
+
+Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
+---
+ create mode 100644 net/netfilter/nf_flow_table_hw.c
+
+--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
+@@ -826,6 +826,13 @@ struct xfrmdev_ops {
+ };
+ #endif
+ 
+struct flow_offload;
+
+enum flow_offload_type {
+	FLOW_OFFLOAD_ADD	= 0,
+	FLOW_OFFLOAD_DEL,
+};
+
+ /*
+  * This structure defines the management hooks for network devices.
+  * The following hooks can be defined; unless noted otherwise, they are
+@@ -1057,6 +1064,10 @@ struct xfrmdev_ops {
+  * int (*ndo_bridge_dellink)(struct net_device *dev, struct nlmsghdr *nlh,
+  *			     u16 flags);
+  *
+ * int (*ndo_flow_offload)(enum flow_offload_type type,
+ *			   struct flow_offload *flow);
+ *	Adds/deletes flow entry to/from net device flowtable.
+ *
+  * int (*ndo_change_carrier)(struct net_device *dev, bool new_carrier);
+  *	Called to change device carrier. Soft-devices (like dummy, team, etc)
+  *	which do not represent real hardware may define this to allow their
+@@ -1281,6 +1292,8 @@ struct net_device_ops {
+ 	int			(*ndo_bridge_dellink)(struct net_device *dev,
+ 						      struct nlmsghdr *nlh,
+ 						      u16 flags);
+	int			(*ndo_flow_offload)(enum flow_offload_type type,
+						    struct flow_offload *flow);
+ 	int			(*ndo_change_carrier)(struct net_device *dev,
+ 						      bool new_carrier);
+ 	int			(*ndo_get_phys_port_id)(struct net_device *dev,
+--- a/include/net/netfilter/nf_flow_table.h
+++ b/include/net/netfilter/nf_flow_table.h
+@@ -20,11 +20,17 @@ struct nf_flowtable_type {
+ 	struct module			*owner;
+ };
+ 
+enum nf_flowtable_flags {
+	NF_FLOWTABLE_F_HW		= 0x1,
+};
+
+ struct nf_flowtable {
+ 	struct list_head		list;
+ 	struct rhashtable		rhashtable;
+ 	const struct nf_flowtable_type	*type;
+	u32				flags;
+ 	struct delayed_work		gc_work;
+	possible_net_t			ft_net;
+ };
+ 
+ enum flow_offload_tuple_dir {
+@@ -69,6 +75,7 @@ struct flow_offload_tuple_rhash {
+ #define FLOW_OFFLOAD_DNAT	0x2
+ #define FLOW_OFFLOAD_DYING	0x4
+ #define FLOW_OFFLOAD_TEARDOWN	0x8
+#define FLOW_OFFLOAD_HW		0x10
+ 
+ struct flow_offload {
+ 	struct flow_offload_tuple_rhash		tuplehash[FLOW_OFFLOAD_DIR_MAX];
+@@ -126,6 +133,22 @@ unsigned int nf_flow_offload_ip_hook(voi
+ unsigned int nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb,
+ 				       const struct nf_hook_state *state);
+ 
+void nf_flow_offload_hw_add(struct net *net, struct flow_offload *flow,
+			    struct nf_conn *ct);
+void nf_flow_offload_hw_del(struct net *net, struct flow_offload *flow);
+
+struct nf_flow_table_hw {
+	struct module	*owner;
+	void		(*add)(struct net *net, struct flow_offload *flow,
+			       struct nf_conn *ct);
+	void		(*del)(struct net *net, struct flow_offload *flow);
+};
+
+int nf_flow_table_hw_register(const struct nf_flow_table_hw *offload);
+void nf_flow_table_hw_unregister(const struct nf_flow_table_hw *offload);
+
+extern struct work_struct nf_flow_offload_hw_work;
+
+ #define MODULE_ALIAS_NF_FLOWTABLE(family)	\
+ 	MODULE_ALIAS("nf-flowtable-" __stringify(family))
+ 
+--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
+@@ -1341,6 +1341,7 @@ enum nft_object_attributes {
+  * @NFTA_FLOWTABLE_HOOK: netfilter hook configuration(NLA_U32)
+  * @NFTA_FLOWTABLE_USE: number of references to this flow table (NLA_U32)
+  * @NFTA_FLOWTABLE_HANDLE: object handle (NLA_U64)
+ * @NFTA_FLOWTABLE_FLAGS: flags (NLA_U32)
+  */
+ enum nft_flowtable_attributes {
+ 	NFTA_FLOWTABLE_UNSPEC,
+@@ -1350,6 +1351,7 @@ enum nft_flowtable_attributes {
+ 	NFTA_FLOWTABLE_USE,
+ 	NFTA_FLOWTABLE_HANDLE,
+ 	NFTA_FLOWTABLE_PAD,
+	NFTA_FLOWTABLE_FLAGS,
+ 	__NFTA_FLOWTABLE_MAX
+ };
+ #define NFTA_FLOWTABLE_MAX	(__NFTA_FLOWTABLE_MAX - 1)
+--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
+@@ -686,6 +686,15 @@ config NF_FLOW_TABLE
+ 
+ 	  To compile it as a module, choose M here.
+ 
+config NF_FLOW_TABLE_HW
+	tristate "Netfilter flow table hardware offload module"
+	depends on NF_FLOW_TABLE
+	help
+	  This option adds hardware offload support for the flow table core
+	  infrastructure.
+
+	  To compile it as a module, choose M here.
+
+ config NETFILTER_XTABLES
+ 	tristate "Netfilter Xtables support (required for ip_tables)"
+ 	default m if NETFILTER_ADVANCED=n
+--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
+@@ -116,6 +116,7 @@ obj-$(CONFIG_NF_FLOW_TABLE)	+= nf_flow_t
+ nf_flow_table-objs := nf_flow_table_core.o nf_flow_table_ip.o
+ 
+ obj-$(CONFIG_NF_FLOW_TABLE_INET) += nf_flow_table_inet.o
+obj-$(CONFIG_NF_FLOW_TABLE_HW)	+= nf_flow_table_hw.o
+ 
+ # generic X tables 
+ obj-$(CONFIG_NETFILTER_XTABLES) += x_tables.o xt_tcpudp.o
+--- a/net/netfilter/nf_flow_table_core.c
+++ b/net/netfilter/nf_flow_table_core.c
+@@ -199,10 +199,16 @@ int flow_offload_add(struct nf_flowtable
+ }
+ EXPORT_SYMBOL_GPL(flow_offload_add);
+ 
+static inline bool nf_flow_in_hw(const struct flow_offload *flow)
+{
+	return flow->flags & FLOW_OFFLOAD_HW;
+}
+
+ static void flow_offload_del(struct nf_flowtable *flow_table,
+ 			     struct flow_offload *flow)
+ {
+ 	struct flow_offload_entry *e;
+	struct net *net = read_pnet(&flow_table->ft_net);
+ 
+ 	rhashtable_remove_fast(&flow_table->rhashtable,
+ 			       &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].node,
+@@ -214,6 +220,9 @@ static void flow_offload_del(struct nf_f
+ 	e = container_of(flow, struct flow_offload_entry, flow);
+ 	clear_bit(IPS_OFFLOAD_BIT, &e->ct->status);
+ 
+	if (nf_flow_in_hw(flow))
+		nf_flow_offload_hw_del(net, flow);
+
+ 	flow_offload_free(flow);
+ }
+ 
+@@ -307,6 +316,7 @@ static int nf_flow_offload_gc_step(struc
+ 	rhashtable_walk_start(&hti);
+ 
+ 	while ((tuplehash = rhashtable_walk_next(&hti))) {
+		bool teardown;
+ 		if (IS_ERR(tuplehash)) {
+ 			err = PTR_ERR(tuplehash);
+ 			if (err != -EAGAIN)
+@@ -319,9 +329,13 @@ static int nf_flow_offload_gc_step(struc
+ 
+ 		flow = container_of(tuplehash, struct flow_offload, tuplehash[0]);
+ 
+-		if (nf_flow_has_expired(flow) ||
+-		    (flow->flags & (FLOW_OFFLOAD_DYING |
+-				    FLOW_OFFLOAD_TEARDOWN)))
+		teardown = flow->flags & (FLOW_OFFLOAD_DYING |
+					  FLOW_OFFLOAD_TEARDOWN);
+
+		if (nf_flow_in_hw(flow) && !teardown)
+			continue;
+
+		if (nf_flow_has_expired(flow) || teardown)
+ 			flow_offload_del(flow_table, flow);
+ 	}
+ out:
+@@ -456,10 +470,43 @@ int nf_flow_dnat_port(const struct flow_
+ }
+ EXPORT_SYMBOL_GPL(nf_flow_dnat_port);
+ 
+static const struct nf_flow_table_hw __rcu *nf_flow_table_hw_hook __read_mostly;
+
+static int nf_flow_offload_hw_init(struct nf_flowtable *flow_table)
+{
+	const struct nf_flow_table_hw *offload;
+
+	if (!rcu_access_pointer(nf_flow_table_hw_hook))
+		request_module("nf-flow-table-hw");
+
+	rcu_read_lock();
+	offload = rcu_dereference(nf_flow_table_hw_hook);
+	if (!offload)
+		goto err_no_hw_offload;
+
+	if (!try_module_get(offload->owner))
+		goto err_no_hw_offload;
+
+	rcu_read_unlock();
+
+	return 0;
+
+err_no_hw_offload:
+	rcu_read_unlock();
+
+	return -EOPNOTSUPP;
+}
+
+ int nf_flow_table_init(struct nf_flowtable *flowtable)
+ {
+ 	int err;
+ 
+	if (flowtable->flags & NF_FLOWTABLE_F_HW) {
+		err = nf_flow_offload_hw_init(flowtable);
+		if (err)
+			return err;
+	}
+
+ 	INIT_DEFERRABLE_WORK(&flowtable->gc_work, nf_flow_offload_work_gc);
+ 
+ 	err = rhashtable_init(&flowtable->rhashtable,
+@@ -497,6 +544,8 @@ static void nf_flow_table_iterate_cleanu
+ {
+ 	nf_flow_table_iterate(flowtable, nf_flow_table_do_cleanup, dev);
+ 	flush_delayed_work(&flowtable->gc_work);
+	if (flowtable->flags & NF_FLOWTABLE_F_HW)
+		flush_work(&nf_flow_offload_hw_work);
+ }
+ 
+ void nf_flow_table_cleanup(struct net *net, struct net_device *dev)
+@@ -510,6 +559,26 @@ void nf_flow_table_cleanup(struct net *n
+ }
+ EXPORT_SYMBOL_GPL(nf_flow_table_cleanup);
+ 
+struct work_struct nf_flow_offload_hw_work;
+EXPORT_SYMBOL_GPL(nf_flow_offload_hw_work);
+
+/* Give the hardware workqueue the chance to remove entries from hardware.*/
+static void nf_flow_offload_hw_free(struct nf_flowtable *flowtable)
+{
+	const struct nf_flow_table_hw *offload;
+
+	flush_work(&nf_flow_offload_hw_work);
+
+	rcu_read_lock();
+	offload = rcu_dereference(nf_flow_table_hw_hook);
+	if (!offload) {
+		rcu_read_unlock();
+		return;
+	}
+	module_put(offload->owner);
+	rcu_read_unlock();
+}
+
+ void nf_flow_table_free(struct nf_flowtable *flow_table)
+ {
+ 	mutex_lock(&flowtable_lock);
+@@ -519,9 +588,58 @@ void nf_flow_table_free(struct nf_flowta
+ 	nf_flow_table_iterate(flow_table, nf_flow_table_do_cleanup, NULL);
+ 	WARN_ON(!nf_flow_offload_gc_step(flow_table));
+ 	rhashtable_destroy(&flow_table->rhashtable);
+	if (flow_table->flags & NF_FLOWTABLE_F_HW)
+		nf_flow_offload_hw_free(flow_table);
+ }
+ EXPORT_SYMBOL_GPL(nf_flow_table_free);
+ 
+/* Must be called from user context. */
+void nf_flow_offload_hw_add(struct net *net, struct flow_offload *flow,
+			    struct nf_conn *ct)
+{
+	const struct nf_flow_table_hw *offload;
+
+	rcu_read_lock();
+	offload = rcu_dereference(nf_flow_table_hw_hook);
+	if (offload)
+		offload->add(net, flow, ct);
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(nf_flow_offload_hw_add);
+
+/* Must be called from user context. */
+void nf_flow_offload_hw_del(struct net *net, struct flow_offload *flow)
+{
+	const struct nf_flow_table_hw *offload;
+
+	rcu_read_lock();
+	offload = rcu_dereference(nf_flow_table_hw_hook);
+	if (offload)
+		offload->del(net, flow);
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(nf_flow_offload_hw_del);
+
+int nf_flow_table_hw_register(const struct nf_flow_table_hw *offload)
+{
+	if (rcu_access_pointer(nf_flow_table_hw_hook))
+		return -EBUSY;
+
+	rcu_assign_pointer(nf_flow_table_hw_hook, offload);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nf_flow_table_hw_register);
+
+void nf_flow_table_hw_unregister(const struct nf_flow_table_hw *offload)
+{
+	WARN_ON(rcu_access_pointer(nf_flow_table_hw_hook) != offload);
+	rcu_assign_pointer(nf_flow_table_hw_hook, NULL);
+
+	synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(nf_flow_table_hw_unregister);
+
+ static int nf_flow_table_netdev_event(struct notifier_block *this,
+ 				      unsigned long event, void *ptr)
+ {
+--- /dev/null
+++ b/net/netfilter/nf_flow_table_hw.c
+@@ -0,0 +1,169 @@
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/netfilter.h>
+#include <linux/rhashtable.h>
+#include <linux/netdevice.h>
+#include <net/netfilter/nf_flow_table.h>
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_core.h>
+#include <net/netfilter/nf_conntrack_tuple.h>
+
+static DEFINE_SPINLOCK(flow_offload_hw_pending_list_lock);
+static LIST_HEAD(flow_offload_hw_pending_list);
+
+static DEFINE_MUTEX(nf_flow_offload_hw_mutex);
+
+struct flow_offload_hw {
+	struct list_head	list;
+	enum flow_offload_type	type;
+	struct flow_offload	*flow;
+	struct nf_conn		*ct;
+	possible_net_t		flow_hw_net;
+};
+
+static int do_flow_offload_hw(struct net *net, struct flow_offload *flow,
+			      int type)
+{
+	struct net_device *indev;
+	int ret, ifindex;
+
+	ifindex = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.iifidx;
+	indev = dev_get_by_index(net, ifindex);
+	if (WARN_ON(!indev))
+		return 0;
+
+	mutex_lock(&nf_flow_offload_hw_mutex);
+	ret = indev->netdev_ops->ndo_flow_offload(type, flow);
+	mutex_unlock(&nf_flow_offload_hw_mutex);
+
+	dev_put(indev);
+
+	return ret;
+}
+
+static void flow_offload_hw_work_add(struct flow_offload_hw *offload)
+{
+	struct net *net;
+	int ret;
+
+	if (nf_ct_is_dying(offload->ct))
+		return;
+
+	net = read_pnet(&offload->flow_hw_net);
+	ret = do_flow_offload_hw(net, offload->flow, FLOW_OFFLOAD_ADD);
+	if (ret >= 0)
+		offload->flow->flags |= FLOW_OFFLOAD_HW;
+}
+
+static void flow_offload_hw_work_del(struct flow_offload_hw *offload)
+{
+	struct net *net = read_pnet(&offload->flow_hw_net);
+
+	do_flow_offload_hw(net, offload->flow, FLOW_OFFLOAD_DEL);
+}
+
+static void flow_offload_hw_work(struct work_struct *work)
+{
+	struct flow_offload_hw *offload, *next;
+	LIST_HEAD(hw_offload_pending);
+
+	spin_lock_bh(&flow_offload_hw_pending_list_lock);
+	list_replace_init(&flow_offload_hw_pending_list, &hw_offload_pending);
+	spin_unlock_bh(&flow_offload_hw_pending_list_lock);
+
+	list_for_each_entry_safe(offload, next, &hw_offload_pending, list) {
+		switch (offload->type) {
+		case FLOW_OFFLOAD_ADD:
+			flow_offload_hw_work_add(offload);
+			break;
+		case FLOW_OFFLOAD_DEL:
+			flow_offload_hw_work_del(offload);
+			break;
+		}
+		if (offload->ct)
+			nf_conntrack_put(&offload->ct->ct_general);
+		list_del(&offload->list);
+		kfree(offload);
+	}
+}
+
+static void flow_offload_queue_work(struct flow_offload_hw *offload)
+{
+	spin_lock_bh(&flow_offload_hw_pending_list_lock);
+	list_add_tail(&offload->list, &flow_offload_hw_pending_list);
+	spin_unlock_bh(&flow_offload_hw_pending_list_lock);
+
+	schedule_work(&nf_flow_offload_hw_work);
+}
+
+static void flow_offload_hw_add(struct net *net, struct flow_offload *flow,
+				struct nf_conn *ct)
+{
+	struct flow_offload_hw *offload;
+
+	offload = kmalloc(sizeof(struct flow_offload_hw), GFP_ATOMIC);
+	if (!offload)
+		return;
+
+	nf_conntrack_get(&ct->ct_general);
+	offload->type = FLOW_OFFLOAD_ADD;
+	offload->ct = ct;
+	offload->flow = flow;
+	write_pnet(&offload->flow_hw_net, net);
+
+	flow_offload_queue_work(offload);
+}
+
+static void flow_offload_hw_del(struct net *net, struct flow_offload *flow)
+{
+	struct flow_offload_hw *offload;
+
+	offload = kmalloc(sizeof(struct flow_offload_hw), GFP_ATOMIC);
+	if (!offload)
+		return;
+
+	offload->type = FLOW_OFFLOAD_DEL;
+	offload->ct = NULL;
+	offload->flow = flow;
+	write_pnet(&offload->flow_hw_net, net);
+
+	flow_offload_queue_work(offload);
+}
+
+static const struct nf_flow_table_hw flow_offload_hw = {
+	.add	= flow_offload_hw_add,
+	.del	= flow_offload_hw_del,
+	.owner	= THIS_MODULE,
+};
+
+static int __init nf_flow_table_hw_module_init(void)
+{
+	INIT_WORK(&nf_flow_offload_hw_work, flow_offload_hw_work);
+	nf_flow_table_hw_register(&flow_offload_hw);
+
+	return 0;
+}
+
+static void __exit nf_flow_table_hw_module_exit(void)
+{
+	struct flow_offload_hw *offload, *next;
+	LIST_HEAD(hw_offload_pending);
+
+	nf_flow_table_hw_unregister(&flow_offload_hw);
+	cancel_work_sync(&nf_flow_offload_hw_work);
+
+	list_for_each_entry_safe(offload, next, &hw_offload_pending, list) {
+		if (offload->ct)
+			nf_conntrack_put(&offload->ct->ct_general);
+		list_del(&offload->list);
+		kfree(offload);
+	}
+}
+
+module_init(nf_flow_table_hw_module_init);
+module_exit(nf_flow_table_hw_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
+MODULE_ALIAS("nf-flow-table-hw");
+--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
+@@ -4866,6 +4866,14 @@ static int nf_tables_flowtable_parse_hoo
+ 	if (err < 0)
+ 		goto err1;
+ 
+	for (i = 0; i < n; i++) {
+		if (flowtable->data.flags & NF_FLOWTABLE_F_HW &&
+		    !dev_array[i]->netdev_ops->ndo_flow_offload) {
+			err = -EOPNOTSUPP;
+			goto err1;
+		}
+	}
+
+ 	ops = kzalloc(sizeof(struct nf_hook_ops) * n, GFP_KERNEL);
+ 	if (!ops) {
+ 		err = -ENOMEM;
+@@ -4996,10 +5004,19 @@ static int nf_tables_newflowtable(struct
+ 	}
+ 
+ 	flowtable->data.type = type;
+	write_pnet(&flowtable->data.ft_net, net);
+
+ 	err = type->init(&flowtable->data);
+ 	if (err < 0)
+ 		goto err3;
+ 
+	if (nla[NFTA_FLOWTABLE_FLAGS]) {
+		flowtable->data.flags =
+			ntohl(nla_get_be32(nla[NFTA_FLOWTABLE_FLAGS]));
+		if (flowtable->data.flags & ~NF_FLOWTABLE_F_HW)
+			goto err4;
+	}
+
+ 	err = nf_tables_flowtable_parse_hook(&ctx, nla[NFTA_FLOWTABLE_HOOK],
+ 					     flowtable);
+ 	if (err < 0)
+@@ -5097,7 +5114,8 @@ static int nf_tables_fill_flowtable_info
+ 	    nla_put_string(skb, NFTA_FLOWTABLE_NAME, flowtable->name) ||
+ 	    nla_put_be32(skb, NFTA_FLOWTABLE_USE, htonl(flowtable->use)) ||
+ 	    nla_put_be64(skb, NFTA_FLOWTABLE_HANDLE, cpu_to_be64(flowtable->handle),
+-			 NFTA_FLOWTABLE_PAD))
+			 NFTA_FLOWTABLE_PAD) ||
+	    nla_put_be32(skb, NFTA_FLOWTABLE_FLAGS, htonl(flowtable->data.flags)))
+ 		goto nla_put_failure;
+ 
+ 	nest = nla_nest_start(skb, NFTA_FLOWTABLE_HOOK);
+--- a/net/netfilter/nft_flow_offload.c
+++ b/net/netfilter/nft_flow_offload.c
+@@ -121,6 +121,9 @@ static void nft_flow_offload_eval(const
+ 	if (ret < 0)
+ 		goto err_flow_add;
+ 
+	if (flowtable->flags & NF_FLOWTABLE_F_HW)
+		nf_flow_offload_hw_add(nft_net(pkt), flow, ct);
+
+ 	return;
+ 
+ err_flow_add:
--- a/target/linux/generic/pending-4.14/641-netfilter-nf_flow_table-support-hw-offload-through-v.patch
+++ b/target/linux/generic/pending-4.14/641-netfilter-nf_flow_table-support-hw-offload-through-v.patch
@ -0,0 +1,302 @@
+From: Felix Fietkau <nbd@nbd.name>
+Date: Thu, 15 Mar 2018 20:46:31 +0100
+Subject: [PATCH] netfilter: nf_flow_table: support hw offload through
+ virtual interfaces
+
+There are hardware offload devices that support offloading VLANs and
+PPPoE devices. Additionally, it is useful to be able to offload packets
+routed through bridge interfaces as well.
+Add support for finding the path to the offload device through these
+virtual interfaces, while collecting useful parameters for the offload
+device, like VLAN ID/protocol, PPPoE session and Ethernet MAC address.
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
+@@ -827,6 +827,7 @@ struct xfrmdev_ops {
+ #endif
+ 
+ struct flow_offload;
+struct flow_offload_hw_path;
+ 
+ enum flow_offload_type {
+ 	FLOW_OFFLOAD_ADD	= 0,
+@@ -1064,8 +1065,15 @@ enum flow_offload_type {
+  * int (*ndo_bridge_dellink)(struct net_device *dev, struct nlmsghdr *nlh,
+  *			     u16 flags);
+  *
+ * int (*ndo_flow_offload_check)(struct flow_offload_hw_path *path);
+ *	For virtual devices like bridges, vlan, and pppoe, fill in the
+ *	underlying network device that can be used for offloading connections.
+ *	Return an error if offloading is not supported.
+ *
+  * int (*ndo_flow_offload)(enum flow_offload_type type,
+- *			   struct flow_offload *flow);
+ *			   struct flow_offload *flow,
+ *			   struct flow_offload_hw_path *src,
+ *			   struct flow_offload_hw_path *dest);
+  *	Adds/deletes flow entry to/from net device flowtable.
+  *
+  * int (*ndo_change_carrier)(struct net_device *dev, bool new_carrier);
+@@ -1292,8 +1300,11 @@ struct net_device_ops {
+ 	int			(*ndo_bridge_dellink)(struct net_device *dev,
+ 						      struct nlmsghdr *nlh,
+ 						      u16 flags);
+	int			(*ndo_flow_offload_check)(struct flow_offload_hw_path *path);
+ 	int			(*ndo_flow_offload)(enum flow_offload_type type,
+-						    struct flow_offload *flow);
+						    struct flow_offload *flow,
+						    struct flow_offload_hw_path *src,
+						    struct flow_offload_hw_path *dest);
+ 	int			(*ndo_change_carrier)(struct net_device *dev,
+ 						      bool new_carrier);
+ 	int			(*ndo_get_phys_port_id)(struct net_device *dev,
+--- a/include/net/netfilter/nf_flow_table.h
+++ b/include/net/netfilter/nf_flow_table.h
+@@ -86,6 +86,21 @@ struct flow_offload {
+ 	};
+ };
+ 
+#define FLOW_OFFLOAD_PATH_ETHERNET	BIT(0)
+#define FLOW_OFFLOAD_PATH_VLAN		BIT(1)
+#define FLOW_OFFLOAD_PATH_PPPOE		BIT(2)
+
+struct flow_offload_hw_path {
+	struct net_device *dev;
+	u32 flags;
+
+	u8 eth_src[ETH_ALEN];
+	u8 eth_dest[ETH_ALEN];
+	u16 vlan_proto;
+	u16 vlan_id;
+	u16 pppoe_sid;
+};
+
+ #define NF_FLOW_TIMEOUT (30 * HZ)
+ 
+ struct nf_flow_route {
+--- a/net/netfilter/nf_flow_table_hw.c
+++ b/net/netfilter/nf_flow_table_hw.c
+@@ -19,48 +19,75 @@ struct flow_offload_hw {
+ 	enum flow_offload_type	type;
+ 	struct flow_offload	*flow;
+ 	struct nf_conn		*ct;
+-	possible_net_t		flow_hw_net;
+
+	struct flow_offload_hw_path src;
+	struct flow_offload_hw_path dest;
+ };
+ 
+-static int do_flow_offload_hw(struct net *net, struct flow_offload *flow,
+-			      int type)
+static void flow_offload_check_ethernet(struct flow_offload_tuple *tuple,
+					struct flow_offload_hw_path *path)
+ {
+-	struct net_device *indev;
+-	int ret, ifindex;
+	struct net_device *dev = path->dev;
+	struct neighbour *n;
+ 
+-	ifindex = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.iifidx;
+-	indev = dev_get_by_index(net, ifindex);
+-	if (WARN_ON(!indev))
+-		return 0;
+	if (dev->type != ARPHRD_ETHER)
+		return;
+ 
+-	mutex_lock(&nf_flow_offload_hw_mutex);
+-	ret = indev->netdev_ops->ndo_flow_offload(type, flow);
+-	mutex_unlock(&nf_flow_offload_hw_mutex);
+	memcpy(path->eth_src, path->dev->dev_addr, ETH_ALEN);
+	n = dst_neigh_lookup(tuple->dst_cache, &tuple->src_v4);
+	if (!n)
+		return;
+ 
+-	dev_put(indev);
+	memcpy(path->eth_dest, n->ha, ETH_ALEN);
+	path->flags |= FLOW_OFFLOAD_PATH_ETHERNET;
+	neigh_release(n);
+}
+ 
+-	return ret;
+static int flow_offload_check_path(struct net *net,
+				   struct flow_offload_tuple *tuple,
+				   struct flow_offload_hw_path *path)
+{
+	struct net_device *dev;
+
+	dev = dev_get_by_index_rcu(net, tuple->iifidx);
+	if (!dev)
+		return -ENOENT;
+
+	path->dev = dev;
+	flow_offload_check_ethernet(tuple, path);
+
+	if (dev->netdev_ops->ndo_flow_offload_check)
+		return dev->netdev_ops->ndo_flow_offload_check(path);
+
+	return 0;
+ }
+ 
+-static void flow_offload_hw_work_add(struct flow_offload_hw *offload)
+static int do_flow_offload_hw(struct flow_offload_hw *offload)
+ {
+-	struct net *net;
+	struct net_device *src_dev = offload->src.dev;
+	struct net_device *dest_dev = offload->dest.dev;
+ 	int ret;
+ 
+-	if (nf_ct_is_dying(offload->ct))
+-		return;
+	ret = src_dev->netdev_ops->ndo_flow_offload(offload->type,
+						    offload->flow,
+						    &offload->src,
+						    &offload->dest);
+ 
+-	net = read_pnet(&offload->flow_hw_net);
+-	ret = do_flow_offload_hw(net, offload->flow, FLOW_OFFLOAD_ADD);
+-	if (ret >= 0)
+-		offload->flow->flags |= FLOW_OFFLOAD_HW;
+	/* restore devices in case the driver mangled them */
+	offload->src.dev = src_dev;
+	offload->dest.dev = dest_dev;
+
+	return ret;
+ }
+ 
+-static void flow_offload_hw_work_del(struct flow_offload_hw *offload)
+static void flow_offload_hw_free(struct flow_offload_hw *offload)
+ {
+-	struct net *net = read_pnet(&offload->flow_hw_net);
+-
+-	do_flow_offload_hw(net, offload->flow, FLOW_OFFLOAD_DEL);
+	dev_put(offload->src.dev);
+	dev_put(offload->dest.dev);
+	if (offload->ct)
+		nf_conntrack_put(&offload->ct->ct_general);
+	list_del(&offload->list);
+	kfree(offload);
+ }
+ 
+ static void flow_offload_hw_work(struct work_struct *work)
+@@ -73,18 +100,22 @@ static void flow_offload_hw_work(struct
+ 	spin_unlock_bh(&flow_offload_hw_pending_list_lock);
+ 
+ 	list_for_each_entry_safe(offload, next, &hw_offload_pending, list) {
+		mutex_lock(&nf_flow_offload_hw_mutex);
+ 		switch (offload->type) {
+ 		case FLOW_OFFLOAD_ADD:
+-			flow_offload_hw_work_add(offload);
+			if (nf_ct_is_dying(offload->ct))
+				break;
+
+			if (do_flow_offload_hw(offload) >= 0)
+				offload->flow->flags |= FLOW_OFFLOAD_HW;
+ 			break;
+ 		case FLOW_OFFLOAD_DEL:
+-			flow_offload_hw_work_del(offload);
+			do_flow_offload_hw(offload);
+ 			break;
+ 		}
+-		if (offload->ct)
+-			nf_conntrack_put(&offload->ct->ct_general);
+-		list_del(&offload->list);
+-		kfree(offload);
+		mutex_unlock(&nf_flow_offload_hw_mutex);
+
+		flow_offload_hw_free(offload);
+ 	}
+ }
+ 
+@@ -97,20 +128,55 @@ static void flow_offload_queue_work(stru
+ 	schedule_work(&nf_flow_offload_hw_work);
+ }
+ 
+static struct flow_offload_hw *
+flow_offload_hw_prepare(struct net *net, struct flow_offload *flow)
+{
+	struct flow_offload_hw_path src = {};
+	struct flow_offload_hw_path dest = {};
+	struct flow_offload_tuple *tuple;
+	struct flow_offload_hw *offload = NULL;
+
+	rcu_read_lock_bh();
+
+	tuple = &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple;
+	if (flow_offload_check_path(net, tuple, &src))
+		goto out;
+
+	tuple = &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple;
+	if (flow_offload_check_path(net, tuple, &dest))
+		goto out;
+
+	if (!src.dev->netdev_ops->ndo_flow_offload)
+		goto out;
+
+	offload = kzalloc(sizeof(struct flow_offload_hw), GFP_ATOMIC);
+	if (!offload)
+		goto out;
+
+	dev_hold(src.dev);
+	dev_hold(dest.dev);
+	offload->src = src;
+	offload->dest = dest;
+	offload->flow = flow;
+
+out:
+	rcu_read_unlock_bh();
+
+	return offload;
+}
+
+ static void flow_offload_hw_add(struct net *net, struct flow_offload *flow,
+ 				struct nf_conn *ct)
+ {
+ 	struct flow_offload_hw *offload;
+ 
+-	offload = kmalloc(sizeof(struct flow_offload_hw), GFP_ATOMIC);
+	offload = flow_offload_hw_prepare(net, flow);
+ 	if (!offload)
+ 		return;
+ 
+ 	nf_conntrack_get(&ct->ct_general);
+ 	offload->type = FLOW_OFFLOAD_ADD;
+ 	offload->ct = ct;
+-	offload->flow = flow;
+-	write_pnet(&offload->flow_hw_net, net);
+ 
+ 	flow_offload_queue_work(offload);
+ }
+@@ -119,14 +185,11 @@ static void flow_offload_hw_del(struct n
+ {
+ 	struct flow_offload_hw *offload;
+ 
+-	offload = kmalloc(sizeof(struct flow_offload_hw), GFP_ATOMIC);
+	offload = flow_offload_hw_prepare(net, flow);
+ 	if (!offload)
+ 		return;
+ 
+ 	offload->type = FLOW_OFFLOAD_DEL;
+-	offload->ct = NULL;
+-	offload->flow = flow;
+-	write_pnet(&offload->flow_hw_net, net);
+ 
+ 	flow_offload_queue_work(offload);
+ }
+@@ -153,12 +216,8 @@ static void __exit nf_flow_table_hw_modu
+ 	nf_flow_table_hw_unregister(&flow_offload_hw);
+ 	cancel_work_sync(&nf_flow_offload_hw_work);
+ 
+-	list_for_each_entry_safe(offload, next, &hw_offload_pending, list) {
+-		if (offload->ct)
+-			nf_conntrack_put(&offload->ct->ct_general);
+-		list_del(&offload->list);
+-		kfree(offload);
+-	}
+	list_for_each_entry_safe(offload, next, &hw_offload_pending, list)
+		flow_offload_hw_free(offload);
+ }
+ 
+ module_init(nf_flow_table_hw_module_init);
--- a/target/linux/generic/pending-4.14/642-net-8021q-support-hardware-flow-table-offload.patch
+++ b/target/linux/generic/pending-4.14/642-net-8021q-support-hardware-flow-table-offload.patch
@ -0,0 +1,56 @@
+From: Felix Fietkau <nbd@nbd.name>
+Date: Thu, 15 Mar 2018 20:49:58 +0100
+Subject: [PATCH] net: 8021q: support hardware flow table offload
+
+Add the VLAN ID and protocol information
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
+@@ -29,8 +29,10 @@
+ #include <linux/net_tstamp.h>
+ #include <linux/etherdevice.h>
+ #include <linux/ethtool.h>
+#include <linux/netfilter.h>
+ #include <net/arp.h>
+ #include <net/switchdev.h>
+#include <net/netfilter/nf_flow_table.h>
+ 
+ #include "vlan.h"
+ #include "vlanproc.h"
+@@ -762,6 +764,25 @@ static int vlan_dev_get_iflink(const str
+ 	return real_dev->ifindex;
+ }
+ 
+static int vlan_dev_flow_offload_check(struct flow_offload_hw_path *path)
+{
+	struct net_device *dev = path->dev;
+	struct vlan_dev_priv *vlan = vlan_dev_priv(dev);
+
+	if (path->flags & FLOW_OFFLOAD_PATH_VLAN)
+		return -EEXIST;
+
+	path->flags |= FLOW_OFFLOAD_PATH_VLAN;
+	path->vlan_proto = vlan->vlan_proto;
+	path->vlan_id = vlan->vlan_id;
+	path->dev = vlan->real_dev;
+
+	if (vlan->real_dev->netdev_ops->ndo_flow_offload_check)
+		return vlan->real_dev->netdev_ops->ndo_flow_offload_check(path);
+
+	return 0;
+}
+
+ static const struct ethtool_ops vlan_ethtool_ops = {
+ 	.get_link_ksettings	= vlan_ethtool_get_link_ksettings,
+ 	.get_drvinfo	        = vlan_ethtool_get_drvinfo,
+@@ -799,6 +820,7 @@ static const struct net_device_ops vlan_
+ 	.ndo_fix_features	= vlan_dev_fix_features,
+ 	.ndo_get_lock_subclass  = vlan_dev_get_lock_subclass,
+ 	.ndo_get_iflink		= vlan_dev_get_iflink,
+	.ndo_flow_offload_check = vlan_dev_flow_offload_check,
+ };
+ 
+ static void vlan_dev_free(struct net_device *dev)
--- a/target/linux/generic/pending-4.14/643-net-bridge-support-hardware-flow-table-offload.patch
+++ b/target/linux/generic/pending-4.14/643-net-bridge-support-hardware-flow-table-offload.patch
@ -0,0 +1,55 @@
+From: Felix Fietkau <nbd@nbd.name>
+Date: Thu, 15 Mar 2018 20:50:37 +0100
+Subject: [PATCH] net: bridge: support hardware flow table offload
+
+Look up the real device and pass it on
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
+@@ -18,6 +18,8 @@
+ #include <linux/ethtool.h>
+ #include <linux/list.h>
+ #include <linux/netfilter_bridge.h>
+#include <linux/netfilter.h>
+#include <net/netfilter/nf_flow_table.h>
+ 
+ #include <linux/uaccess.h>
+ #include "br_private.h"
+@@ -340,6 +342,26 @@ static const struct ethtool_ops br_ethto
+ 	.get_link	= ethtool_op_get_link,
+ };
+ 
+static int br_flow_offload_check(struct flow_offload_hw_path *path)
+{
+	struct net_device *dev = path->dev;
+	struct net_bridge *br = netdev_priv(dev);
+	struct net_bridge_fdb_entry *dst;
+
+	if (!(path->flags & FLOW_OFFLOAD_PATH_ETHERNET))
+		return -EINVAL;
+
+	dst = br_fdb_find_rcu(br, path->eth_dest, path->vlan_id);
+	if (!dst || !dst->dst)
+		return -ENOENT;
+
+	path->dev = dst->dst->dev;
+	if (path->dev->netdev_ops->ndo_flow_offload_check)
+		return path->dev->netdev_ops->ndo_flow_offload_check(path);
+
+	return 0;
+}
+
+ static const struct net_device_ops br_netdev_ops = {
+ 	.ndo_open		 = br_dev_open,
+ 	.ndo_stop		 = br_dev_stop,
+@@ -367,6 +389,7 @@ static const struct net_device_ops br_ne
+ 	.ndo_bridge_setlink	 = br_setlink,
+ 	.ndo_bridge_dellink	 = br_dellink,
+ 	.ndo_features_check	 = passthru_features_check,
+	.ndo_flow_offload_check	 = br_flow_offload_check,
+ };
+ 
+ static struct device_type br_type = {
--- a/target/linux/generic/pending-4.14/644-net-pppoe-support-hardware-flow-table-offload.patch
+++ b/target/linux/generic/pending-4.14/644-net-pppoe-support-hardware-flow-table-offload.patch
@ -0,0 +1,110 @@
+From: Felix Fietkau <nbd@nbd.name>
+Date: Thu, 15 Mar 2018 21:15:00 +0100
+Subject: [PATCH] net: pppoe: support hardware flow table offload
+
+Pass on the PPPoE session ID and the remote MAC address
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
+@@ -56,6 +56,9 @@
+ #include <net/net_namespace.h>
+ #include <net/netns/generic.h>
+ 
+#include <linux/netfilter.h>
+#include <net/netfilter/nf_flow_table.h>
+
+ #define PPP_VERSION	"2.4.2"
+ 
+ /*
+@@ -1383,12 +1386,33 @@ static void ppp_dev_priv_destructor(stru
+ 		ppp_destroy_interface(ppp);
+ }
+ 
+static int ppp_flow_offload_check(struct flow_offload_hw_path *path)
+{
+	struct ppp *ppp = netdev_priv(path->dev);
+	struct ppp_channel *chan;
+	struct channel *pch;
+
+	if (ppp->flags & SC_MULTILINK)
+		return -EOPNOTSUPP;
+
+	if (list_empty(&ppp->channels))
+		return -ENODEV;
+
+	pch = list_first_entry(&ppp->channels, struct channel, clist);
+	chan = pch->chan;
+	if (!chan->ops->flow_offload_check)
+		return -EOPNOTSUPP;
+
+	return chan->ops->flow_offload_check(chan, path);
+}
+
+ static const struct net_device_ops ppp_netdev_ops = {
+ 	.ndo_init	 = ppp_dev_init,
+ 	.ndo_uninit      = ppp_dev_uninit,
+ 	.ndo_start_xmit  = ppp_start_xmit,
+ 	.ndo_do_ioctl    = ppp_net_ioctl,
+ 	.ndo_get_stats64 = ppp_get_stats64,
+	.ndo_flow_offload_check = ppp_flow_offload_check,
+ };
+ 
+ static struct device_type ppp_type = {
+--- a/drivers/net/ppp/pppoe.c
+++ b/drivers/net/ppp/pppoe.c
+@@ -77,6 +77,8 @@
+ #include <linux/file.h>
+ #include <linux/proc_fs.h>
+ #include <linux/seq_file.h>
+#include <linux/netfilter.h>
+#include <net/netfilter/nf_flow_table.h>
+ 
+ #include <linux/nsproxy.h>
+ #include <net/net_namespace.h>
+@@ -970,8 +972,32 @@ static int pppoe_xmit(struct ppp_channel
+ 	return __pppoe_xmit(sk, skb);
+ }
+ 
+static int pppoe_flow_offload_check(struct ppp_channel *chan,
+				    struct flow_offload_hw_path *path)
+{
+	struct sock *sk = (struct sock *)chan->private;
+	struct pppox_sock *po = pppox_sk(sk);
+	struct net_device *dev = po->pppoe_dev;
+
+	if (sock_flag(sk, SOCK_DEAD) ||
+	    !(sk->sk_state & PPPOX_CONNECTED) || !dev)
+		return -ENODEV;
+
+	path->dev = po->pppoe_dev;
+	path->flags |= FLOW_OFFLOAD_PATH_PPPOE;
+	memcpy(path->eth_src, po->pppoe_dev->dev_addr, ETH_ALEN);
+	memcpy(path->eth_dest, po->pppoe_pa.remote, ETH_ALEN);
+	path->pppoe_sid = be16_to_cpu(po->num);
+
+	if (path->dev->netdev_ops->ndo_flow_offload_check)
+		return path->dev->netdev_ops->ndo_flow_offload_check(path);
+
+	return 0;
+}
+
+ static const struct ppp_channel_ops pppoe_chan_ops = {
+ 	.start_xmit = pppoe_xmit,
+	.flow_offload_check = pppoe_flow_offload_check,
+ };
+ 
+ static int pppoe_recvmsg(struct socket *sock, struct msghdr *m,
+--- a/include/linux/ppp_channel.h
+++ b/include/linux/ppp_channel.h
+@@ -32,6 +32,8 @@ struct ppp_channel_ops {
+ 	int	(*start_xmit)(struct ppp_channel *, struct sk_buff *);
+ 	/* Handle an ioctl call that has come in via /dev/ppp. */
+ 	int	(*ioctl)(struct ppp_channel *, unsigned int, unsigned long);
+
+	int	(*flow_offload_check)(struct ppp_channel *, struct flow_offload_hw_path *);
+ };
+ 
+ struct ppp_channel {
--- a/target/linux/generic/pending-4.14/645-netfilter-nf_flow_table-rework-hardware-offload-time.patch
+++ b/target/linux/generic/pending-4.14/645-netfilter-nf_flow_table-rework-hardware-offload-time.patch
@ -0,0 +1,37 @@
+From: Felix Fietkau <nbd@nbd.name>
+Date: Sun, 25 Mar 2018 21:10:55 +0200
+Subject: [PATCH] netfilter: nf_flow_table: rework hardware offload timeout
+ handling
+
+Some offload implementations send keepalive packets + explicit
+notifications of TCP FIN/RST packets. In this case it is more convenient
+to simply let the driver update flow->timeout handling and use the
+regular flow offload gc step.
+
+For drivers that manage their own lifetime, a separate flag can be set
+to avoid gc timeouts.
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/include/net/netfilter/nf_flow_table.h
+++ b/include/net/netfilter/nf_flow_table.h
+@@ -76,6 +76,7 @@ struct flow_offload_tuple_rhash {
+ #define FLOW_OFFLOAD_DYING	0x4
+ #define FLOW_OFFLOAD_TEARDOWN	0x8
+ #define FLOW_OFFLOAD_HW		0x10
+#define FLOW_OFFLOAD_KEEP	0x20
+ 
+ struct flow_offload {
+ 	struct flow_offload_tuple_rhash		tuplehash[FLOW_OFFLOAD_DIR_MAX];
+--- a/net/netfilter/nf_flow_table_core.c
+++ b/net/netfilter/nf_flow_table_core.c
+@@ -332,7 +332,7 @@ static int nf_flow_offload_gc_step(struc
+ 		teardown = flow->flags & (FLOW_OFFLOAD_DYING |
+ 					  FLOW_OFFLOAD_TEARDOWN);
+ 
+-		if (nf_flow_in_hw(flow) && !teardown)
+		if ((flow->flags & FLOW_OFFLOAD_KEEP) && !teardown)
+ 			continue;
+ 
+ 		if (nf_flow_has_expired(flow) || teardown)