Merge branch 'udp_tunnel-add-NIC-RX-port-offload-infrastructure'

Jakub Kicinski says:

====================
udp_tunnel: add NIC RX port offload infrastructure

Kernel has a facility to notify drivers about the UDP tunnel ports
so that devices can recognize tunneled packets. This is important
mostly for RX - devices which don't support CHECKSUM_COMPLETE can
report checksums of inner packets, and compute RSS over inner headers.
Some drivers also match the UDP tunnel ports also for TX, although
doing so may lead to false positives and negatives.

Unfortunately the user experience when trying to take adavantage
of these facilities is suboptimal. First of all there is no way
for users to check which ports are offloaded. Many drivers resort
to printing messages to aid debugging, other use debugfs. Even worse
the availability of the RX features (NETIF_F_RX_UDP_TUNNEL_PORT)
is established purely on the basis of the driver having the ndos
installed. For most drivers, however, the ability to perform offloads
is contingent on device capabilities (driver support multiple device
and firmware versions). Unless driver resorts to hackish clearing
of features set incorrectly by the core - users are left guessing
whether their device really supports UDP tunnel port offload or not.

There is currently no way to indicate or configure whether RX
features include just the checksum offload or checksum and using
inner headers for RSS. Many drivers default to not using inner
headers for RSS because most implementations populate the source
port with entropy from the inner headers. This, however, is not
always the case, for example certain switches are only able to
use a fixed source port during encapsulation.

We have also seen many driver authors get the intricacies of UDP
tunnel port offloads wrong. Most commonly the drivers forget to
perform reference counting, or take sleeping locks in the callbacks.

This work tries to improve the situation by pulling the UDP tunnel
port table maintenance out of the drivers. It turns out that almost
all drivers maintain a fixed size table of ports (in most cases one
per tunnel type), so we can take care of all the refcounting in the
core, and let the driver specify if they need to sleep in the
callbacks or not. The new common implementation will also support
replacing ports - when a port is removed from a full table it will
try to find a previously missing port to take its place.

This patch only implements the core functionality along with a few
drivers I was hoping to test manually [1] along with a test based
on a netdevsim implementation. Following patches will convert all
the drivers. Once that's complete we can remove the ndos, and rely
directly on the new infrastrucutre.

Then after RSS (RXFH) is converted to netlink we can add the ability
to configure the use of inner RSS headers for UDP tunnels.

[1] Unfortunately I wasn't able to, turns out 2 of the devices
I had access to were older generation or had old FW, and they
did not actually support UDP tunnel port notifications (see
the second paragraph). The thrid device appears to program
the UDP ports correctly but it generates bad UDP checksums with
or without these patches. Long story short - I'd appreciate
reviews and testing here..

v4:
 - better build fix (hopefully this one does it..)
v3:
 - fix build issue;
 - improve bnxt changes.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

11 files changed, 1191 insertions, 2 deletions

diff --git a/net/ethtool/Makefile b/net/ethtool/Makefile
index 0c2b94f20499..7a849ff22dad 100644
--- a/net/ethtool/Makefile
+++ b/net/ethtool/Makefile
@@ -6,4 +6,5 @@ obj-$(CONFIG_ETHTOOL_NETLINK)	+= ethtool_nl.o
 
 ethtool_nl-y	:= netlink.o bitset.o strset.o linkinfo.o linkmodes.o \
 		   linkstate.o debug.o wol.o features.o privflags.o rings.o \
-		   channels.o coalesce.o pause.o eee.o tsinfo.o cabletest.o
+		   channels.o coalesce.o pause.o eee.o tsinfo.o cabletest.o \
+		   tunnels.o
diff --git a/net/ethtool/common.c b/net/ethtool/common.c
index c54166713797..ed19573fccd7 100644
--- a/net/ethtool/common.c
+++ b/net/ethtool/common.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 
+#include <linux/ethtool_netlink.h>
 #include <linux/net_tstamp.h>
 #include <linux/phy.h>
 #include <linux/rtnetlink.h>
@@ -272,6 +273,14 @@ const char ts_rx_filter_names[][ETH_GSTRING_LEN] = {
 };
 static_assert(ARRAY_SIZE(ts_rx_filter_names) == __HWTSTAMP_FILTER_CNT);
 
+const char udp_tunnel_type_names[][ETH_GSTRING_LEN] = {
+	[ETHTOOL_UDP_TUNNEL_TYPE_VXLAN]		= "vxlan",
+	[ETHTOOL_UDP_TUNNEL_TYPE_GENEVE]	= "geneve",
+	[ETHTOOL_UDP_TUNNEL_TYPE_VXLAN_GPE]	= "vxlan-gpe",
+};
+static_assert(ARRAY_SIZE(udp_tunnel_type_names) ==
+	      __ETHTOOL_UDP_TUNNEL_TYPE_CNT);
+
 /* return false if legacy contained non-0 deprecated fields
  * maxtxpkt/maxrxpkt. rest of ksettings always updated
  */
diff --git a/net/ethtool/common.h b/net/ethtool/common.h
index b83bef38368c..3d9251c95a8b 100644
--- a/net/ethtool/common.h
+++ b/net/ethtool/common.h
@@ -28,6 +28,7 @@ extern const char wol_mode_names[][ETH_GSTRING_LEN];
 extern const char sof_timestamping_names[][ETH_GSTRING_LEN];
 extern const char ts_tx_type_names[][ETH_GSTRING_LEN];
 extern const char ts_rx_filter_names[][ETH_GSTRING_LEN];
+extern const char udp_tunnel_type_names[][ETH_GSTRING_LEN];
 
 int __ethtool_get_link(struct net_device *dev);
 
diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
index 88fd07f47040..fb9d096faaa4 100644
--- a/net/ethtool/netlink.c
+++ b/net/ethtool/netlink.c
@@ -181,6 +181,12 @@ err:
 	return NULL;
 }
 
+void *ethnl_dump_put(struct sk_buff *skb, struct netlink_callback *cb, u8 cmd)
+{
+	return genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
+			   &ethtool_genl_family, 0, cmd);
+}
+
 void *ethnl_bcastmsg_put(struct sk_buff *skb, u8 cmd)
 {
 	return genlmsg_put(skb, 0, ++ethnl_bcast_seq, &ethtool_genl_family, 0,
@@ -849,6 +855,12 @@ static const struct genl_ops ethtool_genl_ops[] = {
 		.flags	= GENL_UNS_ADMIN_PERM,
 		.doit	= ethnl_act_cable_test_tdr,
 	},
+	{
+		.cmd	= ETHTOOL_MSG_TUNNEL_INFO_GET,
+		.doit	= ethnl_tunnel_info_doit,
+		.start	= ethnl_tunnel_info_start,
+		.dumpit	= ethnl_tunnel_info_dumpit,
+	},
 };
 
 static const struct genl_multicast_group ethtool_nl_mcgrps[] = {
diff --git a/net/ethtool/netlink.h b/net/ethtool/netlink.h
index 9a96b6e90dc2..e2085005caac 100644
--- a/net/ethtool/netlink.h
+++ b/net/ethtool/netlink.h
@@ -19,6 +19,7 @@ int ethnl_fill_reply_header(struct sk_buff *skb, struct net_device *dev,
 struct sk_buff *ethnl_reply_init(size_t payload, struct net_device *dev, u8 cmd,
 				 u16 hdr_attrtype, struct genl_info *info,
 				 void **ehdrp);
+void *ethnl_dump_put(struct sk_buff *skb, struct netlink_callback *cb, u8 cmd);
 void *ethnl_bcastmsg_put(struct sk_buff *skb, u8 cmd);
 int ethnl_multicast(struct sk_buff *skb, struct net_device *dev);
 
@@ -361,5 +362,8 @@ int ethnl_set_pause(struct sk_buff *skb, struct genl_info *info);
 int ethnl_set_eee(struct sk_buff *skb, struct genl_info *info);
 int ethnl_act_cable_test(struct sk_buff *skb, struct genl_info *info);
 int ethnl_act_cable_test_tdr(struct sk_buff *skb, struct genl_info *info);
+int ethnl_tunnel_info_doit(struct sk_buff *skb, struct genl_info *info);
+int ethnl_tunnel_info_start(struct netlink_callback *cb);
+int ethnl_tunnel_info_dumpit(struct sk_buff *skb, struct netlink_callback *cb);
 
 #endif /* _NET_ETHTOOL_NETLINK_H */
diff --git a/net/ethtool/strset.c b/net/ethtool/strset.c
index 773634b6b048..82707b662fe4 100644
--- a/net/ethtool/strset.c
+++ b/net/ethtool/strset.c
@@ -75,6 +75,11 @@ static const struct strset_info info_template[] = {
 		.count		= __HWTSTAMP_FILTER_CNT,
 		.strings	= ts_rx_filter_names,
 	},
+	[ETH_SS_UDP_TUNNEL_TYPES] = {
+		.per_dev	= false,
+		.count		= __ETHTOOL_UDP_TUNNEL_TYPE_CNT,
+		.strings	= udp_tunnel_type_names,
+	},
 };
 
 struct strset_req_info {
diff --git a/net/ethtool/tunnels.c b/net/ethtool/tunnels.c
new file mode 100644
index 000000000000..6b89255f1231
--- /dev/null
+++ b/net/ethtool/tunnels.c
@@ -0,0 +1,259 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/ethtool_netlink.h>
+#include <net/udp_tunnel.h>
+
+#include "bitset.h"
+#include "common.h"
+#include "netlink.h"
+
+static const struct nla_policy
+ethtool_tunnel_info_policy[ETHTOOL_A_TUNNEL_INFO_MAX + 1] = {
+	[ETHTOOL_A_TUNNEL_INFO_UNSPEC]		= { .type = NLA_REJECT },
+	[ETHTOOL_A_TUNNEL_INFO_HEADER]		= { .type = NLA_NESTED },
+};
+
+static_assert(ETHTOOL_UDP_TUNNEL_TYPE_VXLAN == ilog2(UDP_TUNNEL_TYPE_VXLAN));
+static_assert(ETHTOOL_UDP_TUNNEL_TYPE_GENEVE == ilog2(UDP_TUNNEL_TYPE_GENEVE));
+static_assert(ETHTOOL_UDP_TUNNEL_TYPE_VXLAN_GPE ==
+	      ilog2(UDP_TUNNEL_TYPE_VXLAN_GPE));
+
+static ssize_t
+ethnl_tunnel_info_reply_size(const struct ethnl_req_info *req_base,
+			     struct netlink_ext_ack *extack)
+{
+	bool compact = req_base->flags & ETHTOOL_FLAG_COMPACT_BITSETS;
+	const struct udp_tunnel_nic_info *info;
+	unsigned int i;
+	size_t size;
+	int ret;
+
+	info = req_base->dev->udp_tunnel_nic_info;
+	if (!info) {
+		NL_SET_ERR_MSG(extack,
+			       "device does not report tunnel offload info");
+		return -EOPNOTSUPP;
+	}
+
+	size =	nla_total_size(0); /* _INFO_UDP_PORTS */
+
+	for (i = 0; i < UDP_TUNNEL_NIC_MAX_TABLES; i++) {
+		if (!info->tables[i].n_entries)
+			return size;
+
+		size += nla_total_size(0); /* _UDP_TABLE */
+		size +=	nla_total_size(sizeof(u32)); /* _UDP_TABLE_SIZE */
+		ret = ethnl_bitset32_size(&info->tables[i].tunnel_types, NULL,
+					  __ETHTOOL_UDP_TUNNEL_TYPE_CNT,
+					  udp_tunnel_type_names, compact);
+		if (ret < 0)
+			return ret;
+		size += ret;
+
+		size += udp_tunnel_nic_dump_size(req_base->dev, i);
+	}
+
+	return size;
+}
+
+static int
+ethnl_tunnel_info_fill_reply(const struct ethnl_req_info *req_base,
+			     struct sk_buff *skb)
+{
+	bool compact = req_base->flags & ETHTOOL_FLAG_COMPACT_BITSETS;
+	const struct udp_tunnel_nic_info *info;
+	struct nlattr *ports, *table;
+	unsigned int i;
+
+	info = req_base->dev->udp_tunnel_nic_info;
+	if (!info)
+		return -EOPNOTSUPP;
+
+	ports = nla_nest_start(skb, ETHTOOL_A_TUNNEL_INFO_UDP_PORTS);
+	if (!ports)
+		return -EMSGSIZE;
+
+	for (i = 0; i < UDP_TUNNEL_NIC_MAX_TABLES; i++) {
+		if (!info->tables[i].n_entries)
+			break;
+
+		table = nla_nest_start(skb, ETHTOOL_A_TUNNEL_UDP_TABLE);
+		if (!table)
+			goto err_cancel_ports;
+
+		if (nla_put_u32(skb, ETHTOOL_A_TUNNEL_UDP_TABLE_SIZE,
+				info->tables[i].n_entries))
+			goto err_cancel_table;
+
+		if (ethnl_put_bitset32(skb, ETHTOOL_A_TUNNEL_UDP_TABLE_TYPES,
+				       &info->tables[i].tunnel_types, NULL,
+				       __ETHTOOL_UDP_TUNNEL_TYPE_CNT,
+				       udp_tunnel_type_names, compact))
+			goto err_cancel_table;
+
+		if (udp_tunnel_nic_dump_write(req_base->dev, i, skb))
+			goto err_cancel_table;
+
+		nla_nest_end(skb, table);
+	}
+
+	nla_nest_end(skb, ports);
+
+	return 0;
+
+err_cancel_table:
+	nla_nest_cancel(skb, table);
+err_cancel_ports:
+	nla_nest_cancel(skb, ports);
+	return -EMSGSIZE;
+}
+
+static int
+ethnl_tunnel_info_req_parse(struct ethnl_req_info *req_info,
+			    const struct nlmsghdr *nlhdr, struct net *net,
+			    struct netlink_ext_ack *extack, bool require_dev)
+{
+	struct nlattr *tb[ETHTOOL_A_TUNNEL_INFO_MAX + 1];
+	int ret;
+
+	ret = nlmsg_parse(nlhdr, GENL_HDRLEN, tb, ETHTOOL_A_TUNNEL_INFO_MAX,
+			  ethtool_tunnel_info_policy, extack);
+	if (ret < 0)
+		return ret;
+
+	return ethnl_parse_header_dev_get(req_info,
+					  tb[ETHTOOL_A_TUNNEL_INFO_HEADER],
+					  net, extack, require_dev);
+}
+
+int ethnl_tunnel_info_doit(struct sk_buff *skb, struct genl_info *info)
+{
+	struct ethnl_req_info req_info = {};
+	struct sk_buff *rskb;
+	void *reply_payload;
+	int reply_len;
+	int ret;
+
+	ret = ethnl_tunnel_info_req_parse(&req_info, info->nlhdr,
+					  genl_info_net(info), info->extack,
+					  true);
+	if (ret < 0)
+		return ret;
+
+	rtnl_lock();
+	ret = ethnl_tunnel_info_reply_size(&req_info, info->extack);
+	if (ret < 0)
+		goto err_unlock_rtnl;
+	reply_len = ret + ethnl_reply_header_size();
+
+	rskb = ethnl_reply_init(reply_len, req_info.dev,
+				ETHTOOL_MSG_TUNNEL_INFO_GET,
+				ETHTOOL_A_TUNNEL_INFO_HEADER,
+				info, &reply_payload);
+	if (!rskb) {
+		ret = -ENOMEM;
+		goto err_unlock_rtnl;
+	}
+
+	ret = ethnl_tunnel_info_fill_reply(&req_info, rskb);
+	if (ret)
+		goto err_free_msg;
+	rtnl_unlock();
+	dev_put(req_info.dev);
+	genlmsg_end(rskb, reply_payload);
+
+	return genlmsg_reply(rskb, info);
+
+err_free_msg:
+	nlmsg_free(rskb);
+err_unlock_rtnl:
+	rtnl_unlock();
+	dev_put(req_info.dev);
+	return ret;
+}
+
+struct ethnl_tunnel_info_dump_ctx {
+	struct ethnl_req_info	req_info;
+	int			pos_hash;
+	int			pos_idx;
+};
+
+int ethnl_tunnel_info_start(struct netlink_callback *cb)
+{
+	struct ethnl_tunnel_info_dump_ctx *ctx = (void *)cb->ctx;
+	int ret;
+
+	BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));
+
+	memset(ctx, 0, sizeof(*ctx));
+
+	ret = ethnl_tunnel_info_req_parse(&ctx->req_info, cb->nlh,
+					  sock_net(cb->skb->sk), cb->extack,
+					  false);
+	if (ctx->req_info.dev) {
+		dev_put(ctx->req_info.dev);
+		ctx->req_info.dev = NULL;
+	}
+
+	return ret;
+}
+
+int ethnl_tunnel_info_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct ethnl_tunnel_info_dump_ctx *ctx = (void *)cb->ctx;
+	struct net *net = sock_net(skb->sk);
+	int s_idx = ctx->pos_idx;
+	int h, idx = 0;
+	int ret = 0;
+	void *ehdr;
+
+	rtnl_lock();
+	cb->seq = net->dev_base_seq;
+	for (h = ctx->pos_hash; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {
+		struct hlist_head *head;
+		struct net_device *dev;
+
+		head = &net->dev_index_head[h];
+		idx = 0;
+		hlist_for_each_entry(dev, head, index_hlist) {
+			if (idx < s_idx)
+				goto cont;
+
+			ehdr = ethnl_dump_put(skb, cb,
+					      ETHTOOL_MSG_TUNNEL_INFO_GET);
+			if (!ehdr) {
+				ret = -EMSGSIZE;
+				goto out;
+			}
+
+			ret = ethnl_fill_reply_header(skb, dev, ETHTOOL_A_TUNNEL_INFO_HEADER);
+			if (ret < 0) {
+				genlmsg_cancel(skb, ehdr);
+				goto out;
+			}
+
+			ctx->req_info.dev = dev;
+			ret = ethnl_tunnel_info_fill_reply(&ctx->req_info, skb);
+			ctx->req_info.dev = NULL;
+			if (ret < 0) {
+				genlmsg_cancel(skb, ehdr);
+				if (ret == -EOPNOTSUPP)
+					goto cont;
+				goto out;
+			}
+			genlmsg_end(skb, ehdr);
+cont:
+			idx++;
+		}
+	}
+out:
+	rtnl_unlock();
+
+	ctx->pos_hash = h;
+	ctx->pos_idx = idx;
+	nl_dump_check_consistent(cb, nlmsg_hdr(skb));
+
+	if (ret == -EMSGSIZE && skb->len)
+		return skb->len;
+	return ret;
+}
diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index 9e1a186a3671..5b77a46885b9 100644
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -14,7 +14,7 @@ obj-y     := route.o inetpeer.o protocol.o \
 	     udp_offload.o arp.o icmp.o devinet.o af_inet.o igmp.o \
 	     fib_frontend.o fib_semantics.o fib_trie.o fib_notifier.o \
 	     inet_fragment.o ping.o ip_tunnel_core.o gre_offload.o \
-	     metrics.o netlink.o nexthop.o
+	     metrics.o netlink.o nexthop.o udp_tunnel_stub.o
 
 obj-$(CONFIG_BPFILTER) += bpfilter/
 
@@ -29,6 +29,7 @@ gre-y := gre_demux.o
 obj-$(CONFIG_NET_FOU) += fou.o
 obj-$(CONFIG_NET_IPGRE_DEMUX) += gre.o
 obj-$(CONFIG_NET_IPGRE) += ip_gre.o
+udp_tunnel-y := udp_tunnel_core.o udp_tunnel_nic.o
 obj-$(CONFIG_NET_UDP_TUNNEL) += udp_tunnel.o
 obj-$(CONFIG_NET_IPVTI) += ip_vti.o
 obj-$(CONFIG_SYN_COOKIES) += syncookies.o
diff --git a/net/ipv4/udp_tunnel.c b/net/ipv4/udp_tunnel_core.c
index 3eecba0874aa..3eecba0874aa 100644
--- a/net/ipv4/udp_tunnel.c
+++ b/net/ipv4/udp_tunnel_core.c
diff --git a/net/ipv4/udp_tunnel_nic.c b/net/ipv4/udp_tunnel_nic.c
new file mode 100644
index 000000000000..f0dbd9905a53
--- /dev/null
+++ b/net/ipv4/udp_tunnel_nic.c
@@ -0,0 +1,890 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (c) 2020 Facebook Inc.
+
+#include <linux/ethtool_netlink.h>
+#include <linux/netdevice.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/workqueue.h>
+#include <net/udp_tunnel.h>
+
+enum udp_tunnel_nic_table_entry_flags {
+	UDP_TUNNEL_NIC_ENTRY_ADD	= BIT(0),
+	UDP_TUNNEL_NIC_ENTRY_DEL	= BIT(1),
+	UDP_TUNNEL_NIC_ENTRY_OP_FAIL	= BIT(2),
+	UDP_TUNNEL_NIC_ENTRY_FROZEN	= BIT(3),
+};
+
+struct udp_tunnel_nic_table_entry {
+	__be16 port;
+	u8 type;
+	u8 use_cnt;
+	u8 flags;
+	u8 hw_priv;
+};
+
+/**
+ * struct udp_tunnel_nic - UDP tunnel port offload state
+ * @work:	async work for talking to hardware from process context
+ * @dev:	netdev pointer
+ * @need_sync:	at least one port start changed
+ * @need_replay: space was freed, we need a replay of all ports
+ * @work_pending: @work is currently scheduled
+ * @n_tables:	number of tables under @entries
+ * @missed:	bitmap of tables which overflown
+ * @entries:	table of tables of ports currently offloaded
+ */
+struct udp_tunnel_nic {
+	struct work_struct work;
+
+	struct net_device *dev;
+
+	u8 need_sync:1;
+	u8 need_replay:1;
+	u8 work_pending:1;
+
+	unsigned int n_tables;
+	unsigned long missed;
+	struct udp_tunnel_nic_table_entry **entries;
+};
+
+/* We ensure all work structs are done using driver state, but not the code.
+ * We need a workqueue we can flush before module gets removed.
+ */
+static struct workqueue_struct *udp_tunnel_nic_workqueue;
+
+static const char *udp_tunnel_nic_tunnel_type_name(unsigned int type)
+{
+	switch (type) {
+	case UDP_TUNNEL_TYPE_VXLAN:
+		return "vxlan";
+	case UDP_TUNNEL_TYPE_GENEVE:
+		return "geneve";
+	case UDP_TUNNEL_TYPE_VXLAN_GPE:
+		return "vxlan-gpe";
+	default:
+		return "unknown";
+	}
+}
+
+static bool
+udp_tunnel_nic_entry_is_free(struct udp_tunnel_nic_table_entry *entry)
+{
+	return entry->use_cnt == 0 && !entry->flags;
+}
+
+static bool
+udp_tunnel_nic_entry_is_present(struct udp_tunnel_nic_table_entry *entry)
+{
+	return entry->use_cnt && !(entry->flags & ~UDP_TUNNEL_NIC_ENTRY_FROZEN);
+}
+
+static bool
+udp_tunnel_nic_entry_is_frozen(struct udp_tunnel_nic_table_entry *entry)
+{
+	return entry->flags & UDP_TUNNEL_NIC_ENTRY_FROZEN;
+}
+
+static void
+udp_tunnel_nic_entry_freeze_used(struct udp_tunnel_nic_table_entry *entry)
+{
+	if (!udp_tunnel_nic_entry_is_free(entry))
+		entry->flags |= UDP_TUNNEL_NIC_ENTRY_FROZEN;
+}
+
+static void
+udp_tunnel_nic_entry_unfreeze(struct udp_tunnel_nic_table_entry *entry)
+{
+	entry->flags &= ~UDP_TUNNEL_NIC_ENTRY_FROZEN;
+}
+
+static bool
+udp_tunnel_nic_entry_is_queued(struct udp_tunnel_nic_table_entry *entry)
+{
+	return entry->flags & (UDP_TUNNEL_NIC_ENTRY_ADD |
+			       UDP_TUNNEL_NIC_ENTRY_DEL);
+}
+
+static void
+udp_tunnel_nic_entry_queue(struct udp_tunnel_nic *utn,
+			   struct udp_tunnel_nic_table_entry *entry,
+			   unsigned int flag)
+{
+	entry->flags |= flag;
+	utn->need_sync = 1;
+}
+
+static void
+udp_tunnel_nic_ti_from_entry(struct udp_tunnel_nic_table_entry *entry,
+			     struct udp_tunnel_info *ti)
+{
+	memset(ti, 0, sizeof(*ti));
+	ti->port = entry->port;
+	ti->type = entry->type;
+	ti->hw_priv = entry->hw_priv;
+}
+
+static bool
+udp_tunnel_nic_is_empty(struct net_device *dev, struct udp_tunnel_nic *utn)
+{
+	const struct udp_tunnel_nic_info *info = dev->udp_tunnel_nic_info;
+	unsigned int i, j;
+
+	for (i = 0; i < utn->n_tables; i++)
+		for (j = 0; j < info->tables[i].n_entries; j++)
+			if (!udp_tunnel_nic_entry_is_free(&utn->entries[i][j]))
+				return false;
+	return true;
+}
+
+static bool
+udp_tunnel_nic_should_replay(struct net_device *dev, struct udp_tunnel_nic *utn)
+{
+	const struct udp_tunnel_nic_table_info *table;
+	unsigned int i, j;
+
+	if (!utn->missed)
+		return false;
+
+	for (i = 0; i < utn->n_tables; i++) {
+		table = &dev->udp_tunnel_nic_info->tables[i];
+		if (!test_bit(i, &utn->missed))
+			continue;
+
+		for (j = 0; j < table->n_entries; j++)
+			if (udp_tunnel_nic_entry_is_free(&utn->entries[i][j]))
+				return true;
+	}
+
+	return false;
+}
+
+static void
+__udp_tunnel_nic_get_port(struct net_device *dev, unsigned int table,
+			  unsigned int idx, struct udp_tunnel_info *ti)
+{
+	struct udp_tunnel_nic_table_entry *entry;
+	struct udp_tunnel_nic *utn;
+
+	utn = dev->udp_tunnel_nic;
+	entry = &utn->entries[table][idx];
+
+	if (entry->use_cnt)
+		udp_tunnel_nic_ti_from_entry(entry, ti);
+}
+
+static void
+__udp_tunnel_nic_set_port_priv(struct net_device *dev, unsigned int table,
+			       unsigned int idx, u8 priv)
+{
+	dev->udp_tunnel_nic->entries[table][idx].hw_priv = priv;
+}
+
+static void
+udp_tunnel_nic_entry_update_done(struct udp_tunnel_nic_table_entry *entry,
+				 int err)
+{
+	bool dodgy = entry->flags & UDP_TUNNEL_NIC_ENTRY_OP_FAIL;
+
+	WARN_ON_ONCE(entry->flags & UDP_TUNNEL_NIC_ENTRY_ADD &&
+		     entry->flags & UDP_TUNNEL_NIC_ENTRY_DEL);
+
+	if (entry->flags & UDP_TUNNEL_NIC_ENTRY_ADD &&
+	    (!err || (err == -EEXIST && dodgy)))
+		entry->flags &= ~UDP_TUNNEL_NIC_ENTRY_ADD;
+
+	if (entry->flags & UDP_TUNNEL_NIC_ENTRY_DEL &&
+	    (!err || (err == -ENOENT && dodgy)))
+		entry->flags &= ~UDP_TUNNEL_NIC_ENTRY_DEL;
+
+	if (!err)
+		entry->flags &= ~UDP_TUNNEL_NIC_ENTRY_OP_FAIL;
+	else
+		entry->flags |= UDP_TUNNEL_NIC_ENTRY_OP_FAIL;
+}
+
+static void
+udp_tunnel_nic_device_sync_one(struct net_device *dev,
+			       struct udp_tunnel_nic *utn,
+			       unsigned int table, unsigned int idx)
+{
+	struct udp_tunnel_nic_table_entry *entry;
+	struct udp_tunnel_info ti;
+	int err;
+
+	entry = &utn->entries[table][idx];
+	if (!udp_tunnel_nic_entry_is_queued(entry))
+		return;
+
+	udp_tunnel_nic_ti_from_entry(entry, &ti);
+	if (entry->flags & UDP_TUNNEL_NIC_ENTRY_ADD)
+		err = dev->udp_tunnel_nic_info->set_port(dev, table, idx, &ti);
+	else
+		err = dev->udp_tunnel_nic_info->unset_port(dev, table, idx,
+							   &ti);
+	udp_tunnel_nic_entry_update_done(entry, err);
+
+	if (err)
+		netdev_warn(dev,
+			    "UDP tunnel port sync failed port %d type %s: %d\n",
+			    be16_to_cpu(entry->port),
+			    udp_tunnel_nic_tunnel_type_name(entry->type),
+			    err);
+}
+
+static void
+udp_tunnel_nic_device_sync_by_port(struct net_device *dev,
+				   struct udp_tunnel_nic *utn)
+{
+	const struct udp_tunnel_nic_info *info = dev->udp_tunnel_nic_info;
+	unsigned int i, j;
+
+	for (i = 0; i < utn->n_tables; i++)
+		for (j = 0; j < info->tables[i].n_entries; j++)
+			udp_tunnel_nic_device_sync_one(dev, utn, i, j);
+}
+
+static void
+udp_tunnel_nic_device_sync_by_table(struct net_device *dev,
+				    struct udp_tunnel_nic *utn)
+{
+	const struct udp_tunnel_nic_info *info = dev->udp_tunnel_nic_info;
+	unsigned int i, j;
+	int err;
+
+	for (i = 0; i < utn->n_tables; i++) {
+		/* Find something that needs sync in this table */
+		for (j = 0; j < info->tables[i].n_entries; j++)
+			if (udp_tunnel_nic_entry_is_queued(&utn->entries[i][j]))
+				break;
+		if (j == info->tables[i].n_entries)
+			continue;
+
+		err = info->sync_table(dev, i);
+		if (err)
+			netdev_warn(dev, "UDP tunnel port sync failed for table %d: %d\n",
+				    i, err);
+
+		for (j = 0; j < info->tables[i].n_entries; j++) {
+			struct udp_tunnel_nic_table_entry *entry;
+
+			entry = &utn->entries[i][j];
+			if (udp_tunnel_nic_entry_is_queued(entry))
+				udp_tunnel_nic_entry_update_done(entry, err);
+		}
+	}
+}
+
+static void
+__udp_tunnel_nic_device_sync(struct net_device *dev, struct udp_tunnel_nic *utn)
+{
+	if (!utn->need_sync)
+		return;
+
+	if (dev->udp_tunnel_nic_info->sync_table)
+		udp_tunnel_nic_device_sync_by_table(dev, utn);
+	else
+		udp_tunnel_nic_device_sync_by_port(dev, utn);
+
+	utn->need_sync = 0;
+	/* Can't replay directly here, in case we come from the tunnel driver's
+	 * notification - trying to replay may deadlock inside tunnel driver.
+	 */
+	utn->need_replay = udp_tunnel_nic_should_replay(dev, utn);
+}
+
+static void
+udp_tunnel_nic_device_sync(struct net_device *dev, struct udp_tunnel_nic *utn)
+{
+	const struct udp_tunnel_nic_info *info = dev->udp_tunnel_nic_info;
+	bool may_sleep;
+
+	if (!utn->need_sync)
+		return;
+
+	/* Drivers which sleep in the callback need to update from
+	 * the workqueue, if we come from the tunnel driver's notification.
+	 */
+	may_sleep = info->flags & UDP_TUNNEL_NIC_INFO_MAY_SLEEP;
+	if (!may_sleep)
+		__udp_tunnel_nic_device_sync(dev, utn);
+	if (may_sleep || utn->need_replay) {
+		queue_work(udp_tunnel_nic_workqueue, &utn->work);
+		utn->work_pending = 1;
+	}
+}
+
+static bool
+udp_tunnel_nic_table_is_capable(const struct udp_tunnel_nic_table_info *table,
+				struct udp_tunnel_info *ti)
+{
+	return table->tunnel_types & ti->type;
+}
+
+static bool
+udp_tunnel_nic_is_capable(struct net_device *dev, struct udp_tunnel_nic *utn,
+			  struct udp_tunnel_info *ti)
+{
+	const struct udp_tunnel_nic_info *info = dev->udp_tunnel_nic_info;
+	unsigned int i;
+
+	/* Special case IPv4-only NICs */
+	if (info->flags & UDP_TUNNEL_NIC_INFO_IPV4_ONLY &&
+	    ti->sa_family != AF_INET)
+		return false;
+
+	for (i = 0; i < utn->n_tables; i++)
+		if (udp_tunnel_nic_table_is_capable(&info->tables[i], ti))
+			return true;
+	return false;
+}
+
+static int
+udp_tunnel_nic_has_collision(struct net_device *dev, struct udp_tunnel_nic *utn,
+			     struct udp_tunnel_info *ti)
+{
+	const struct udp_tunnel_nic_info *info = dev->udp_tunnel_nic_info;
+	struct udp_tunnel_nic_table_entry *entry;
+	unsigned int i, j;
+
+	for (i = 0; i < utn->n_tables; i++)
+		for (j = 0; j < info->tables[i].n_entries; j++) {
+			entry =	&utn->entries[i][j];
+
+			if (!udp_tunnel_nic_entry_is_free(entry) &&
+			    entry->port == ti->port &&
+			    entry->type != ti->type) {
+				__set_bit(i, &utn->missed);
+				return true;
+			}
+		}
+	return false;
+}
+
+static void
+udp_tunnel_nic_entry_adj(struct udp_tunnel_nic *utn,
+			 unsigned int table, unsigned int idx, int use_cnt_adj)
+{
+	struct udp_tunnel_nic_table_entry *entry =  &utn->entries[table][idx];
+	bool dodgy = entry->flags & UDP_TUNNEL_NIC_ENTRY_OP_FAIL;
+	unsigned int from, to;
+
+	/* If not going from used to unused or vice versa - all done.
+	 * For dodgy entries make sure we try to sync again (queue the entry).
+	 */
+	entry->use_cnt += use_cnt_adj;
+	if (!dodgy && !entry->use_cnt == !(entry->use_cnt - use_cnt_adj))
+		return;
+
+	/* Cancel the op before it was sent to the device, if possible,
+	 * otherwise we'd need to take special care to issue commands
+	 * in the same order the ports arrived.
+	 */
+	if (use_cnt_adj < 0) {
+		from = UDP_TUNNEL_NIC_ENTRY_ADD;
+		to = UDP_TUNNEL_NIC_ENTRY_DEL;
+	} else {
+		from = UDP_TUNNEL_NIC_ENTRY_DEL;
+		to = UDP_TUNNEL_NIC_ENTRY_ADD;
+	}
+
+	if (entry->flags & from) {
+		entry->flags &= ~from;
+		if (!dodgy)
+			return;
+	}
+
+	udp_tunnel_nic_entry_queue(utn, entry, to);
+}
+
+static bool
+udp_tunnel_nic_entry_try_adj(struct udp_tunnel_nic *utn,
+			     unsigned int table, unsigned int idx,
+			     struct udp_tunnel_info *ti, int use_cnt_adj)
+{
+	struct udp_tunnel_nic_table_entry *entry =  &utn->entries[table][idx];
+
+	if (udp_tunnel_nic_entry_is_free(entry) ||
+	    entry->port != ti->port ||
+	    entry->type != ti->type)
+		return false;
+
+	if (udp_tunnel_nic_entry_is_frozen(entry))
+		return true;
+
+	udp_tunnel_nic_entry_adj(utn, table, idx, use_cnt_adj);
+	return true;
+}
+
+/* Try to find existing matching entry and adjust its use count, instead of
+ * adding a new one. Returns true if entry was found. In case of delete the
+ * entry may have gotten removed in the process, in which case it will be
+ * queued for removal.
+ */
+static bool
+udp_tunnel_nic_try_existing(struct net_device *dev, struct udp_tunnel_nic *utn,
+			    struct udp_tunnel_info *ti, int use_cnt_adj)
+{
+	const struct udp_tunnel_nic_table_info *table;
+	unsigned int i, j;
+
+	for (i = 0; i < utn->n_tables; i++) {
+		table = &dev->udp_tunnel_nic_info->tables[i];
+		if (!udp_tunnel_nic_table_is_capable(table, ti))
+			continue;
+
+		for (j = 0; j < table->n_entries; j++)
+			if (udp_tunnel_nic_entry_try_adj(utn, i, j, ti,
+							 use_cnt_adj))
+				return true;
+	}
+
+	return false;
+}
+
+static bool
+udp_tunnel_nic_add_existing(struct net_device *dev, struct udp_tunnel_nic *utn,
+			    struct udp_tunnel_info *ti)
+{
+	return udp_tunnel_nic_try_existing(dev, utn, ti, +1);
+}
+
+static bool
+udp_tunnel_nic_del_existing(struct net_device *dev, struct udp_tunnel_nic *utn,
+			    struct udp_tunnel_info *ti)
+{
+	return udp_tunnel_nic_try_existing(dev, utn, ti, -1);
+}
+
+static bool
+udp_tunnel_nic_add_new(struct net_device *dev, struct udp_tunnel_nic *utn,
+		       struct udp_tunnel_info *ti)
+{
+	const struct udp_tunnel_nic_table_info *table;
+	unsigned int i, j;
+
+	for (i = 0; i < utn->n_tables; i++) {
+		table = &dev->udp_tunnel_nic_info->tables[i];
+		if (!udp_tunnel_nic_table_is_capable(table, ti))
+			continue;
+
+		for (j = 0; j < table->n_entries; j++) {
+			struct udp_tunnel_nic_table_entry *entry;
+
+			entry = &utn->entries[i][j];
+			if (!udp_tunnel_nic_entry_is_free(entry))
+				continue;
+
+			entry->port = ti->port;
+			entry->type = ti->type;
+			entry->use_cnt = 1;
+			udp_tunnel_nic_entry_queue(utn, entry,
+						   UDP_TUNNEL_NIC_ENTRY_ADD);
+			return true;
+		}
+
+		/* The different table may still fit this port in, but there
+		 * are no devices currently which have multiple tables accepting
+		 * the same tunnel type, and false positives are okay.
+		 */
+		__set_bit(i, &utn->missed);
+	}
+
+	return false;
+}
+
+static void
+__udp_tunnel_nic_add_port(struct net_device *dev, struct udp_tunnel_info *ti)
+{
+	const struct udp_tunnel_nic_info *info = dev->udp_tunnel_nic_info;
+	struct udp_tunnel_nic *utn;
+
+	utn = dev->udp_tunnel_nic;
+	if (!utn)
+		return;
+	if (!netif_running(dev) && info->flags & UDP_TUNNEL_NIC_INFO_OPEN_ONLY)
+		return;
+
+	if (!udp_tunnel_nic_is_capable(dev, utn, ti))
+		return;
+
+	/* It may happen that a tunnel of one type is removed and different
+	 * tunnel type tries to reuse its port before the device was informed.
+	 * Rely on utn->missed to re-add this port later.
+	 */
+	if (udp_tunnel_nic_has_collision(dev, utn, ti))
+		return;
+
+	if (!udp_tunnel_nic_add_existing(dev, utn, ti))
+		udp_tunnel_nic_add_new(dev, utn, ti);
+
+	udp_tunnel_nic_device_sync(dev, utn);
+}
+
+static void
+__udp_tunnel_nic_del_port(struct net_device *dev, struct udp_tunnel_info *ti)
+{
+	struct udp_tunnel_nic *utn;
+
+	utn = dev->udp_tunnel_nic;
+	if (!utn)
+		return;
+
+	if (!udp_tunnel_nic_is_capable(dev, utn, ti))
+		return;
+
+	udp_tunnel_nic_del_existing(dev, utn, ti);
+
+	udp_tunnel_nic_device_sync(dev, utn);
+}
+
+static void __udp_tunnel_nic_reset_ntf(struct net_device *dev)
+{
+	const struct udp_tunnel_nic_info *info = dev->udp_tunnel_nic_info;
+	struct udp_tunnel_nic *utn;
+	unsigned int i, j;
+
+	ASSERT_RTNL();
+
+	utn = dev->udp_tunnel_nic;
+	if (!utn)
+		return;
+
+	utn->need_sync = false;
+	for (i = 0; i < utn->n_tables; i++)
+		for (j = 0; j < info->tables[i].n_entries; j++) {
+			struct udp_tunnel_nic_table_entry *entry;
+
+			entry = &utn->entries[i][j];
+
+			entry->flags &= ~(UDP_TUNNEL_NIC_ENTRY_DEL |
+					  UDP_TUNNEL_NIC_ENTRY_OP_FAIL);
+			/* We don't release rtnl across ops */
+			WARN_ON(entry->flags & UDP_TUNNEL_NIC_ENTRY_FROZEN);
+			if (!entry->use_cnt)
+				continue;
+
+			udp_tunnel_nic_entry_queue(utn, entry,
+						   UDP_TUNNEL_NIC_ENTRY_ADD);
+		}
+
+	__udp_tunnel_nic_device_sync(dev, utn);
+}
+
+static size_t
+__udp_tunnel_nic_dump_size(struct net_device *dev, unsigned int table)
+{
+	const struct udp_tunnel_nic_info *info = dev->udp_tunnel_nic_info;
+	struct udp_tunnel_nic *utn;
+	unsigned int j;
+	size_t size;
+
+	utn = dev->udp_tunnel_nic;
+	if (!utn)
+		return 0;
+
+	size = 0;
+	for (j = 0; j < info->tables[table].n_entries; j++) {
+		if (!udp_tunnel_nic_entry_is_present(&utn->entries[table][j]))
+			continue;
+
+		size += nla_total_size(0) +		 /* _TABLE_ENTRY */
+			nla_total_size(sizeof(__be16)) + /* _ENTRY_PORT */
+			nla_total_size(sizeof(u32));	 /* _ENTRY_TYPE */
+	}
+
+	return size;
+}
+
+static int
+__udp_tunnel_nic_dump_write(struct net_device *dev, unsigned int table,
+			    struct sk_buff *skb)
+{
+	const struct udp_tunnel_nic_info *info = dev->udp_tunnel_nic_info;
+	struct udp_tunnel_nic *utn;
+	struct nlattr *nest;
+	unsigned int j;
+
+	utn = dev->udp_tunnel_nic;
+	if (!utn)
+		return 0;
+
+	for (j = 0; j < info->tables[table].n_entries; j++) {
+		if (!udp_tunnel_nic_entry_is_present(&utn->entries[table][j]))
+			continue;
+
+		nest = nla_nest_start(skb, ETHTOOL_A_TUNNEL_UDP_TABLE_ENTRY);
+
+		if (nla_put_be16(skb, ETHTOOL_A_TUNNEL_UDP_ENTRY_PORT,
+				 utn->entries[table][j].port) ||
+		    nla_put_u32(skb, ETHTOOL_A_TUNNEL_UDP_ENTRY_TYPE,
+				ilog2(utn->entries[table][j].type)))
+			goto err_cancel;
+
+		nla_nest_end(skb, nest);
+	}
+
+	return 0;
+
+err_cancel:
+	nla_nest_cancel(skb, nest);
+	return -EMSGSIZE;
+}
+
+static const struct udp_tunnel_nic_ops __udp_tunnel_nic_ops = {
+	.get_port	= __udp_tunnel_nic_get_port,
+	.set_port_priv	= __udp_tunnel_nic_set_port_priv,
+	.add_port	= __udp_tunnel_nic_add_port,
+	.del_port	= __udp_tunnel_nic_del_port,
+	.reset_ntf	= __udp_tunnel_nic_reset_ntf,
+	.dump_size	= __udp_tunnel_nic_dump_size,
+	.dump_write	= __udp_tunnel_nic_dump_write,
+};
+
+static void
+udp_tunnel_nic_flush(struct net_device *dev, struct udp_tunnel_nic *utn)
+{
+	const struct udp_tunnel_nic_info *info = dev->udp_tunnel_nic_info;
+	unsigned int i, j;
+
+	for (i = 0; i < utn->n_tables; i++)
+		for (j = 0; j < info->tables[i].n_entries; j++) {
+			int adj_cnt = -utn->entries[i][j].use_cnt;
+
+			if (adj_cnt)
+				udp_tunnel_nic_entry_adj(utn, i, j, adj_cnt);
+		}
+
+	__udp_tunnel_nic_device_sync(dev, utn);
+
+	for (i = 0; i < utn->n_tables; i++)
+		memset(utn->entries[i], 0, array_size(info->tables[i].n_entries,
+						      sizeof(**utn->entries)));
+	WARN_ON(utn->need_sync);
+	utn->need_replay = 0;
+}
+
+static void
+udp_tunnel_nic_replay(struct net_device *dev, struct udp_tunnel_nic *utn)
+{
+	const struct udp_tunnel_nic_info *info = dev->udp_tunnel_nic_info;
+	unsigned int i, j;
+
+	/* Freeze all the ports we are already tracking so that the replay
+	 * does not double up the refcount.
+	 */
+	for (i = 0; i < utn->n_tables; i++)
+		for (j = 0; j < info->tables[i].n_entries; j++)
+			udp_tunnel_nic_entry_freeze_used(&utn->entries[i][j]);
+	utn->missed = 0;
+	utn->need_replay = 0;
+
+	udp_tunnel_get_rx_info(dev);
+
+	for (i = 0; i < utn->n_tables; i++)
+		for (j = 0; j < info->tables[i].n_entries; j++)
+			udp_tunnel_nic_entry_unfreeze(&utn->entries[i][j]);
+}
+
+static void udp_tunnel_nic_device_sync_work(struct work_struct *work)
+{
+	struct udp_tunnel_nic *utn =
+		container_of(work, struct udp_tunnel_nic, work);
+
+	rtnl_lock();
+	utn->work_pending = 0;
+	__udp_tunnel_nic_device_sync(utn->dev, utn);
+
+	if (utn->need_replay)
+		udp_tunnel_nic_replay(utn->dev, utn);
+	rtnl_unlock();
+}
+
+static struct udp_tunnel_nic *
+udp_tunnel_nic_alloc(const struct udp_tunnel_nic_info *info,
+		     unsigned int n_tables)
+{
+	struct udp_tunnel_nic *utn;
+	unsigned int i;
+
+	utn = kzalloc(sizeof(*utn), GFP_KERNEL);
+	if (!utn)
+		return NULL;
+	utn->n_tables = n_tables;
+	INIT_WORK(&utn->work, udp_tunnel_nic_device_sync_work);
+
+	utn->entries = kmalloc_array(n_tables, sizeof(void *), GFP_KERNEL);
+	if (!utn->entries)
+		goto err_free_utn;
+
+	for (i = 0; i < n_tables; i++) {
+		utn->entries[i] = kcalloc(info->tables[i].n_entries,
+					  sizeof(*utn->entries[i]), GFP_KERNEL);
+		if (!utn->entries[i])
+			goto err_free_prev_entries;
+	}
+
+	return utn;
+
+err_free_prev_entries:
+	while (i--)
+		kfree(utn->entries[i]);
+	kfree(utn->entries);
+err_free_utn:
+	kfree(utn);
+	return NULL;
+}
+
+static int udp_tunnel_nic_register(struct net_device *dev)
+{
+	const struct udp_tunnel_nic_info *info = dev->udp_tunnel_nic_info;
+	struct udp_tunnel_nic *utn;
+	unsigned int n_tables, i;
+
+	BUILD_BUG_ON(sizeof(utn->missed) * BITS_PER_BYTE <
+		     UDP_TUNNEL_NIC_MAX_TABLES);
+
+	if (WARN_ON(!info->set_port != !info->unset_port) ||
+	    WARN_ON(!info->set_port == !info->sync_table) ||
+	    WARN_ON(!info->tables[0].n_entries))
+		return -EINVAL;
+
+	n_tables = 1;
+	for (i = 1; i < UDP_TUNNEL_NIC_MAX_TABLES; i++) {
+		if (!info->tables[i].n_entries)
+			continue;
+
+		n_tables++;
+		if (WARN_ON(!info->tables[i - 1].n_entries))
+			return -EINVAL;
+	}
+
+	utn = udp_tunnel_nic_alloc(info, n_tables);
+	if (!utn)
+		return -ENOMEM;
+
+	utn->dev = dev;
+	dev_hold(dev);
+	dev->udp_tunnel_nic = utn;
+
+	if (!(info->flags & UDP_TUNNEL_NIC_INFO_OPEN_ONLY))
+		udp_tunnel_get_rx_info(dev);
+
+	return 0;
+}
+
+static void
+udp_tunnel_nic_unregister(struct net_device *dev, struct udp_tunnel_nic *utn)
+{
+	unsigned int i;
+
+	/* Flush before we check work, so we don't waste time adding entries
+	 * from the work which we will boot immediately.
+	 */
+	udp_tunnel_nic_flush(dev, utn);
+
+	/* Wait for the work to be done using the state, netdev core will
+	 * retry unregister until we give up our reference on this device.
+	 */
+	if (utn->work_pending)
+		return;
+
+	for (i = 0; i < utn->n_tables; i++)
+		kfree(utn->entries[i]);
+	kfree(utn->entries);
+	kfree(utn);
+	dev->udp_tunnel_nic = NULL;
+	dev_put(dev);
+}
+
+static int
+udp_tunnel_nic_netdevice_event(struct notifier_block *unused,
+			       unsigned long event, void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+	const struct udp_tunnel_nic_info *info;
+	struct udp_tunnel_nic *utn;
+
+	info = dev->udp_tunnel_nic_info;
+	if (!info)
+		return NOTIFY_DONE;
+
+	if (event == NETDEV_REGISTER) {
+		int err;
+
+		err = udp_tunnel_nic_register(dev);
+		if (err)
+			netdev_WARN(dev, "failed to register for UDP tunnel offloads: %d", err);
+		return notifier_from_errno(err);
+	}
+	/* All other events will need the udp_tunnel_nic state */
+	utn = dev->udp_tunnel_nic;
+	if (!utn)
+		return NOTIFY_DONE;
+
+	if (event == NETDEV_UNREGISTER) {
+		udp_tunnel_nic_unregister(dev, utn);
+		return NOTIFY_OK;
+	}
+
+	/* All other events only matter if NIC has to be programmed open */
+	if (!(info->flags & UDP_TUNNEL_NIC_INFO_OPEN_ONLY))
+		return NOTIFY_DONE;
+
+	if (event == NETDEV_UP) {
+		WARN_ON(!udp_tunnel_nic_is_empty(dev, utn));
+		udp_tunnel_get_rx_info(dev);
+		return NOTIFY_OK;
+	}
+	if (event == NETDEV_GOING_DOWN) {
+		udp_tunnel_nic_flush(dev, utn);
+		return NOTIFY_OK;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block udp_tunnel_nic_notifier_block __read_mostly = {
+	.notifier_call = udp_tunnel_nic_netdevice_event,
+};
+
+static int __init udp_tunnel_nic_init_module(void)
+{
+	int err;
+
+	udp_tunnel_nic_workqueue = alloc_workqueue("udp_tunnel_nic", 0, 0);
+	if (!udp_tunnel_nic_workqueue)
+		return -ENOMEM;
+
+	rtnl_lock();
+	udp_tunnel_nic_ops = &__udp_tunnel_nic_ops;
+	rtnl_unlock();
+
+	err = register_netdevice_notifier(&udp_tunnel_nic_notifier_block);
+	if (err)
+		goto err_unset_ops;
+
+	return 0;
+
+err_unset_ops:
+	rtnl_lock();
+	udp_tunnel_nic_ops = NULL;
+	rtnl_unlock();
+	destroy_workqueue(udp_tunnel_nic_workqueue);
+	return err;
+}
+late_initcall(udp_tunnel_nic_init_module);
+
+static void __exit udp_tunnel_nic_cleanup_module(void)
+{
+	unregister_netdevice_notifier(&udp_tunnel_nic_notifier_block);
+
+	rtnl_lock();
+	udp_tunnel_nic_ops = NULL;
+	rtnl_unlock();
+
+	destroy_workqueue(udp_tunnel_nic_workqueue);
+}
+module_exit(udp_tunnel_nic_cleanup_module);
+
+MODULE_LICENSE("GPL");
diff --git a/net/ipv4/udp_tunnel_stub.c b/net/ipv4/udp_tunnel_stub.c
new file mode 100644
index 000000000000..c4b2888f5fef
--- /dev/null
+++ b/net/ipv4/udp_tunnel_stub.c
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (c) 2020 Facebook Inc.
+
+#include <net/udp_tunnel.h>
+
+const struct udp_tunnel_nic_ops *udp_tunnel_nic_ops;
+EXPORT_SYMBOL_GPL(udp_tunnel_nic_ops);