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* [PATCH net-next] amt: add initial driver for Automatic Multicast Tunneling (AMT)
@ 2021-10-23 19:30 Taehee Yoo
  2021-10-26  0:46 ` Jakub Kicinski
  0 siblings, 1 reply; 3+ messages in thread
From: Taehee Yoo @ 2021-10-23 19:30 UTC (permalink / raw)
  To: davem, kuba, netdev, linux-kernel; +Cc: ap420073

This is an implementation of AMT(Automatic Multicast Tunneling), RFC 7450.
https://datatracker.ietf.org/doc/html/rfc7450

This implementation supports IGMPv2, IGMPv3, MLDv1. MLDv2, and IPv4
underlay.

 Summary of RFC 7450
The purpose of this protocol is to provide multicast tunneling.
The main use-case of this protocol is to provide delivery multicast
traffic from a multicast-enabled network to sites that lack multicast
connectivity to the source network.
There are two roles in AMT protocol, Gateway, and Relay.
The main purpose of Gateway mode is to forward multicast listening
information(IGMP, MLD) to the source.
The main purpose of Relay mode is to forward multicast data to listeners.
These multicast traffics(IGMP, MLD, multicast data packets) are tunneled.

Listeners are located behind Gateway endpoint.
But gateway itself can be a listener too.
Senders are located behind Relay endpoint.

    ___________       _________       _______       ________
   |           |     |         |     |       |     |        |
   | Listeners <-----> Gateway <-----> Relay <-----> Source |
   |___________|     |_________|     |_______|     |________|
      IGMP/MLD---------(encap)----------->
	 <-------------(decap)--------(encap)------Multicast Data

 Usage of AMT interface
1. Create gateway interface
ip link add amtg type amt mode gateway local 10.0.0.1 discovery 10.0.0.2 \
dev gw1_rt gateway_port 2268 relay_port 2268

2. Create Relay interface
ip link add amtr type amt mode relay local 10.0.0.2 dev relay_rt \
relay_port 2268 max_tunnels 4

Signed-off-by: Taehee Yoo <ap420073@gmail.com>
---
 MAINTAINERS              |    8 +
 drivers/net/Kconfig      |    7 +
 drivers/net/Makefile     |    1 +
 drivers/net/amt.c        | 3301 ++++++++++++++++++++++++++++++++++++++
 include/net/amt.h        |  377 +++++
 include/uapi/linux/amt.h |   30 +
 6 files changed, 3724 insertions(+)
 create mode 100644 drivers/net/amt.c
 create mode 100644 include/net/amt.h
 create mode 100644 include/uapi/linux/amt.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 4bd5819869ca..cfa1379a8637 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1020,6 +1020,14 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/iio/light/ams,as73211.yaml
 F:	drivers/iio/light/as73211.c
 
+AMT (Automatic Multicast Tunneling)
+M:	Taehee Yoo <ap420073@gmail.com>
+L:	netdev@vger.kernel.org
+S:	Maintained
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git
+F:	drivers/net/amt.c
+
 ANALOG DEVICES INC AD7192 DRIVER
 M:	Alexandru Tachici <alexandru.tachici@analog.com>
 L:	linux-iio@vger.kernel.org
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index f37b1c56f7c4..3d3d1469e8f0 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -291,6 +291,13 @@ config GTP
 	  To compile this drivers as a module, choose M here: the module
 	  will be called gtp.
 
+config AMT
+	tristate "Automatic Multicast Tunneling (AMT)"
+	depends on INET && IP_MULTICAST
+	select NET_UDP_TUNNEL
+	help
+	   AMT is an tunneling standard for Multicast.
+
 config MACSEC
 	tristate "IEEE 802.1AE MAC-level encryption (MACsec)"
 	select CRYPTO
diff --git a/drivers/net/Makefile b/drivers/net/Makefile
index 739838623cf6..50b23e71065f 100644
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_WIREGUARD) += wireguard/
 obj-$(CONFIG_EQUALIZER) += eql.o
 obj-$(CONFIG_IFB) += ifb.o
 obj-$(CONFIG_MACSEC) += macsec.o
+obj-$(CONFIG_AMT) += amt.o
 obj-$(CONFIG_MACVLAN) += macvlan.o
 obj-$(CONFIG_MACVTAP) += macvtap.o
 obj-$(CONFIG_MII) += mii.o
diff --git a/drivers/net/amt.c b/drivers/net/amt.c
new file mode 100644
index 000000000000..e9dc1b79139f
--- /dev/null
+++ b/drivers/net/amt.c
@@ -0,0 +1,3301 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Copyright (c) 2021 Taehee Yoo <ap420073@gmail.com> */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/udp.h>
+#include <linux/jhash.h>
+#include <linux/if_tunnel.h>
+#include <linux/net.h>
+#include <linux/igmp.h>
+#include <net/net_namespace.h>
+#include <net/protocol.h>
+#include <net/ip.h>
+#include <net/udp.h>
+#include <net/udp_tunnel.h>
+#include <net/icmp.h>
+#include <net/mld.h>
+#include <net/amt.h>
+#include <uapi/linux/amt.h>
+#include <linux/security.h>
+#include <net/gro_cells.h>
+#include <net/ipv6.h>
+#include <net/protocol.h>
+#include <net/if_inet6.h>
+#include <net/ndisc.h>
+#include <net/addrconf.h>
+#include <net/ip6_route.h>
+#include <net/inet_common.h>
+
+static HLIST_HEAD(source_gc_list);
+/* Lock for source_gc_list */
+static spinlock_t source_gc_lock;
+static struct delayed_work source_gc_wq;
+static struct workqueue_struct *amt_wq;
+static char *status_str[] = {
+	"AMT_STATUS_INIT",
+	"AMT_STATUS_SENT_DISCOVERY",
+	"AMT_STATUS_RECEIVED_DISCOVERY",
+	"AMT_STATUS_SENT_ADVERTISEMENT",
+	"AMT_STATUS_RECEIVED_ADVERTISEMENT",
+	"AMT_STATUS_SENT_REQUEST",
+	"AMT_STATUS_RECEIVED_REQUEST",
+	"AMT_STATUS_SENT_QUERY",
+	"AMT_STATUS_RECEIVED_QUERY",
+	"AMT_STATUS_SENT_UPDATE",
+	"AMT_STATUS_RECEIVED_UPDATE",
+};
+
+static char *type_str[] = {
+	"AMT_MSG_DISCOVERY",
+	"AMT_MSG_ADVERTISEMENT",
+	"AMT_MSG_REQUEST",
+	"AMT_MSG_MEMBERSHIP_QUERY",
+	"AMT_MSG_MEMBERSHIP_UPDATE",
+	"AMT_MSG_MULTICAST_DATA",
+	"AMT_MSG_TEATDOWM",
+};
+
+static char *action_str[] = {
+	"AMT_ACT_GMI",
+	"AMT_ACT_GMI_ZERO",
+	"AMT_ACT_GT",
+	"AMT_ACT_STATUS_FWD_NEW",
+	"AMT_ACT_STATUS_D_FWD_NEW",
+	"AMT_ACT_STATUS_NONE_NEW",
+};
+
+static struct igmpv3_grec igmpv3_zero_grec;
+
+#if IS_ENABLED(CONFIG_IPV6)
+#define MLD2_ALL_NODE_INIT { { { 0xff, 0x02, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x01 } } }
+static struct in6_addr mld2_all_node = MLD2_ALL_NODE_INIT;
+static struct mld2_grec mldv2_zero_grec;
+#endif
+
+static struct amt_skb_cb *amt_skb_cb(struct sk_buff *skb)
+{
+	return (struct amt_skb_cb *)((void *)skb->cb +
+		sizeof(struct qdisc_skb_cb));
+}
+
+static bool amt_addr_equal(union amt_addr *a, union amt_addr *b)
+{
+	return !memcmp(a, b, sizeof(union amt_addr));
+}
+
+static void __amt_source_gc_work(void)
+{
+	struct amt_source_node *snode;
+	struct hlist_head gc_list;
+	struct hlist_node *t;
+
+	spin_lock_bh(&source_gc_lock);
+	hlist_move_list(&source_gc_list, &gc_list);
+	spin_unlock_bh(&source_gc_lock);
+
+	hlist_for_each_entry_safe(snode, t, &gc_list, node) {
+		hlist_del_rcu(&snode->node);
+		kfree_rcu(snode, rcu);
+	}
+}
+
+static void amt_source_gc_work(struct work_struct *work)
+{
+	__amt_source_gc_work();
+
+	spin_lock_bh(&source_gc_lock);
+	mod_delayed_work(amt_wq, &source_gc_wq,
+			 msecs_to_jiffies(AMT_GC_INTERVAL));
+	spin_unlock_bh(&source_gc_lock);
+}
+
+static u32 amt_source_hash(struct amt_tunnel_list *tunnel, union amt_addr *src)
+{
+	u32 hash = jhash(src, sizeof(*src), tunnel->amt->hash_seed);
+
+	return reciprocal_scale(hash, tunnel->amt->hash_buckets);
+}
+
+static bool amt_status_filter(struct amt_source_node *snode,
+			      enum amt_filter filter)
+{
+	switch (filter) {
+	case AMT_FILTER_FWD:
+		if (snode->status == AMT_SOURCE_STATUS_FWD &&
+		    snode->flags == AMT_SOURCE_OLD)
+			return true;
+		else
+			return false;
+	case AMT_FILTER_D_FWD:
+		if (snode->status == AMT_SOURCE_STATUS_D_FWD &&
+		    snode->flags == AMT_SOURCE_OLD)
+			return true;
+		else
+			return false;
+	case AMT_FILTER_FWD_NEW:
+		if (snode->status == AMT_SOURCE_STATUS_FWD &&
+		    snode->flags == AMT_SOURCE_NEW)
+			return true;
+		else
+			return false;
+	case AMT_FILTER_D_FWD_NEW:
+		if (snode->status == AMT_SOURCE_STATUS_D_FWD &&
+		    snode->flags == AMT_SOURCE_NEW)
+			return true;
+		else
+			return false;
+	case AMT_FILTER_ALL:
+		return true;
+	case AMT_FILTER_NONE_NEW:
+		if (snode->status == AMT_SOURCE_STATUS_NONE &&
+		    snode->flags == AMT_SOURCE_NEW)
+			return true;
+		else
+			return false;
+	case AMT_FILTER_BOTH:
+		if ((snode->status == AMT_SOURCE_STATUS_D_FWD ||
+		     snode->status == AMT_SOURCE_STATUS_FWD) &&
+		    snode->flags == AMT_SOURCE_OLD)
+			return true;
+		else
+			return false;
+	case AMT_FILTER_BOTH_NEW:
+		if ((snode->status == AMT_SOURCE_STATUS_D_FWD ||
+		     snode->status == AMT_SOURCE_STATUS_FWD) &&
+		    snode->flags == AMT_SOURCE_NEW)
+			return true;
+		else
+			return false;
+	default:
+		return false;
+	}
+
+	return false;
+}
+
+static struct amt_source_node *amt_lookup_src(struct amt_tunnel_list *tunnel,
+					      struct amt_group_node *gnode,
+					      enum amt_filter filter,
+					      union amt_addr *src)
+{
+	u32 hash = amt_source_hash(tunnel, src);
+	struct amt_source_node *snode;
+
+	hlist_for_each_entry_rcu(snode, &gnode->sources[hash], node)
+		if (amt_status_filter(snode, filter) &&
+		    amt_addr_equal(&snode->source_addr, src))
+			return snode;
+
+	return NULL;
+}
+
+static u32 amt_group_hash(struct amt_tunnel_list *tunnel, union amt_addr *group)
+{
+	u32 hash = jhash(group, sizeof(*group), tunnel->amt->hash_seed);
+
+	return reciprocal_scale(hash, tunnel->amt->hash_buckets);
+}
+
+static struct amt_group_node *amt_lookup_group(struct amt_tunnel_list *tunnel,
+					       union amt_addr *group,
+					       union amt_addr *host,
+					       __be16 family)
+{
+	u32 hash = amt_group_hash(tunnel, group);
+	struct amt_group_node *gnode;
+
+	hlist_for_each_entry_rcu(gnode, &tunnel->groups[hash], node) {
+		if (amt_addr_equal(&gnode->group_addr, group) &&
+		    amt_addr_equal(&gnode->host_addr, host) &&
+		    gnode->family == family)
+			return gnode;
+	}
+
+	return NULL;
+}
+
+static void amt_destroy_source(struct amt_source_node *snode)
+{
+	struct amt_group_node *gnode = snode->gnode;
+	struct amt_tunnel_list *tunnel;
+
+	tunnel = gnode->tunnel_list;
+
+	if (gnode->family == ETH_P_IP) {
+		netdev_dbg(snode->gnode->amt->dev,
+			   "Delete source %pI4 from %pI4\n",
+			   &snode->source_addr.ip4,
+			   &gnode->group_addr.ip4);
+#if IS_ENABLED(CONFIG_IPV6)
+	} else if (gnode->family == ETH_P_IPV6) {
+		netdev_dbg(snode->gnode->amt->dev,
+			   "Delete source %pI6 from %pI6\n",
+			   &snode->source_addr.ip6,
+			   &gnode->group_addr.ip6);
+#endif
+	}
+
+	cancel_delayed_work(&snode->source_timer);
+	hlist_del_init_rcu(&snode->node);
+	tunnel->nr_sources--;
+	gnode->nr_sources--;
+	spin_lock_bh(&source_gc_lock);
+	hlist_add_head_rcu(&snode->node, &source_gc_list);
+	spin_unlock_bh(&source_gc_lock);
+}
+
+static void amt_del_group(struct amt_dev *amt, struct amt_group_node *gnode)
+{
+	struct amt_source_node *snode;
+	struct hlist_node *t;
+	int i;
+
+	if (cancel_delayed_work(&gnode->group_timer))
+		dev_put(amt->dev);
+	hlist_del_rcu(&gnode->node);
+	gnode->tunnel_list->nr_groups--;
+
+	if (gnode->family == ETH_P_IP)
+		netdev_dbg(amt->dev, "Leave group %pI4\n",
+			   &gnode->group_addr.ip4);
+#if IS_ENABLED(CONFIG_IPV6)
+	else if (gnode->family == ETH_P_IPV6)
+		netdev_dbg(amt->dev, "Leave group %pI6\n",
+			   &gnode->group_addr.ip6);
+#endif
+	for (i = 0; i < amt->hash_buckets; i++)
+		hlist_for_each_entry_safe(snode, t, &gnode->sources[i], node)
+			amt_destroy_source(snode);
+
+	/* tunnel->lock was acquired outside of amt_del_group()
+	 * But rcu_read_lock() was acquired too so It's safe.
+	 */
+	kfree_rcu(gnode, rcu);
+}
+
+/* If a source timer expires with a router filter-mode for the group of
+ * INCLUDE, the router concludes that traffic from this particular
+ * source is no longer desired on the attached network, and deletes the
+ * associated source record.
+ */
+static void amt_source_work(struct work_struct *work)
+{
+	struct amt_source_node *snode = container_of(to_delayed_work(work),
+						     struct amt_source_node,
+						     source_timer);
+	struct amt_group_node *gnode = snode->gnode;
+	struct amt_dev *amt = gnode->amt;
+	struct amt_tunnel_list *tunnel;
+
+	tunnel = gnode->tunnel_list;
+	spin_lock_bh(&tunnel->lock);
+	rcu_read_lock();
+	if (gnode->filter_mode == MCAST_INCLUDE) {
+		amt_destroy_source(snode);
+		if (!gnode->nr_sources)
+			amt_del_group(amt, gnode);
+	} else {
+/* When a router filter-mode for a group is EXCLUDE, source records are
+ * only deleted when the group timer expires
+ */
+		snode->status = AMT_SOURCE_STATUS_D_FWD;
+	}
+	rcu_read_unlock();
+	spin_unlock_bh(&tunnel->lock);
+}
+
+static void amt_act_src(struct amt_tunnel_list *tunnel,
+			struct amt_group_node *gnode,
+			struct amt_source_node *snode,
+			enum amt_act act)
+{
+	struct amt_dev *amt = tunnel->amt;
+
+	switch (act) {
+	case AMT_ACT_GMI:
+		mod_delayed_work(amt_wq, &snode->source_timer,
+				 msecs_to_jiffies(amt_gmi(amt)));
+		break;
+	case AMT_ACT_GMI_ZERO:
+		cancel_delayed_work(&snode->source_timer);
+		break;
+	case AMT_ACT_GT:
+		mod_delayed_work(amt_wq, &snode->source_timer,
+				 gnode->group_timer.timer.expires);
+		break;
+	case AMT_ACT_STATUS_FWD_NEW:
+		snode->status = AMT_SOURCE_STATUS_FWD;
+		snode->flags = AMT_SOURCE_NEW;
+		break;
+	case AMT_ACT_STATUS_D_FWD_NEW:
+		snode->status = AMT_SOURCE_STATUS_D_FWD;
+		snode->flags = AMT_SOURCE_NEW;
+		break;
+	case AMT_ACT_STATUS_NONE_NEW:
+		cancel_delayed_work(&snode->source_timer);
+		snode->status = AMT_SOURCE_STATUS_NONE;
+		snode->flags = AMT_SOURCE_NEW;
+		break;
+	default:
+		return;
+	}
+
+	if (gnode->family == ETH_P_IP)
+		netdev_dbg(amt->dev, "Source %pI4 from %pI4 Acted %s\n",
+			   &snode->source_addr.ip4,
+			   &gnode->group_addr.ip4,
+			   action_str[act]);
+#if IS_ENABLED(CONFIG_IPV6)
+	else
+		netdev_dbg(amt->dev, "Source %pI6 from %pI6 Acted %s\n",
+			   &snode->source_addr.ip6,
+			   &gnode->group_addr.ip6,
+			   action_str[act]);
+#endif
+}
+
+static struct amt_source_node *amt_alloc_snode(struct amt_group_node *gnode,
+					       union amt_addr *src)
+{
+	struct amt_source_node *snode;
+
+	snode = kzalloc(sizeof(*snode), GFP_ATOMIC);
+	if (!snode)
+		return NULL;
+
+	memcpy(&snode->source_addr, src, sizeof(union amt_addr));
+	snode->gnode = gnode;
+	snode->status = AMT_SOURCE_STATUS_NONE;
+	snode->flags = AMT_SOURCE_NEW;
+	INIT_HLIST_NODE(&snode->node);
+	INIT_DELAYED_WORK(&snode->source_timer, amt_source_work);
+
+	return snode;
+}
+
+/* RFC 3810 - 7.2.2.  Definition of Filter Timers
+ *
+ *    Router               Filter
+ *  Filter Mode          Timer Value          Actions/Comments
+ *  -----------       -----------------       ----------------
+ *
+ *    INCLUDE             Not Used            All listeners in
+ *                                            INCLUDE mode.
+ *
+ *    EXCLUDE             Timer > 0           At least one listener
+ *                                            in EXCLUDE mode.
+ *
+ *    EXCLUDE             Timer == 0          No more listeners in
+ *                                            EXCLUDE mode for the
+ *                                            multicast address.
+ *                                            If the Requested List
+ *                                            is empty, delete
+ *                                            Multicast Address
+ *                                            Record.  If not, switch
+ *                                            to INCLUDE filter mode;
+ *                                            the sources in the
+ *                                            Requested List are
+ *                                            moved to the Include
+ *                                            List, and the Exclude
+ *                                            List is deleted.
+ */
+static void amt_group_work(struct work_struct *work)
+{
+	struct amt_group_node *gnode = container_of(to_delayed_work(work),
+						    struct amt_group_node,
+						    group_timer);
+	struct amt_tunnel_list *tunnel = gnode->tunnel_list;
+	struct amt_dev *amt = gnode->amt;
+	struct amt_source_node *snode;
+	bool delete_group = true;
+	struct hlist_node *t;
+	int i, buckets;
+
+	buckets = amt->hash_buckets;
+
+	spin_lock_bh(&tunnel->lock);
+	if (gnode->filter_mode == MCAST_INCLUDE) {
+		/* Not Used */
+		spin_unlock_bh(&tunnel->lock);
+		goto out;
+	}
+
+	rcu_read_lock();
+	for (i = 0; i < buckets; i++) {
+		hlist_for_each_entry_safe(snode, t,
+					  &gnode->sources[i], node) {
+			if (!delayed_work_pending(&snode->source_timer) ||
+			    snode->status == AMT_SOURCE_STATUS_D_FWD) {
+				amt_destroy_source(snode);
+			} else {
+				delete_group = false;
+				snode->status = AMT_SOURCE_STATUS_FWD;
+			}
+		}
+	}
+	if (delete_group)
+		amt_del_group(amt, gnode);
+	else
+		gnode->filter_mode = MCAST_INCLUDE;
+	rcu_read_unlock();
+	spin_unlock_bh(&tunnel->lock);
+out:
+	dev_put(amt->dev);
+}
+
+/* Non-existant group is created as INCLUDE {empty}:
+ *
+ * RFC 3376 - 5.1. Action on Change of Interface State
+ *
+ * If no interface state existed for that multicast address before
+ * the change (i.e., the change consisted of creating a new
+ * per-interface record), or if no state exists after the change
+ * (i.e., the change consisted of deleting a per-interface record),
+ * then the "non-existent" state is considered to have a filter mode
+ * of INCLUDE and an empty source list.
+ */
+static struct amt_group_node *amt_add_group(struct amt_dev *amt,
+					    struct amt_tunnel_list *tunnel,
+					    union amt_addr *group,
+					    union amt_addr *host,
+					    __be16 family)
+{
+	struct amt_group_node *gnode;
+	u32 hash;
+	int i;
+
+	if (tunnel->nr_groups >= amt->max_groups)
+		return ERR_PTR(-ENOSPC);
+
+	gnode = kmalloc(sizeof(*gnode) +
+			(sizeof(struct hlist_head) * amt->hash_buckets),
+			GFP_ATOMIC);
+	if (unlikely(!gnode))
+		return ERR_PTR(-ENOMEM);
+
+	gnode->nr_sources = 0;
+	gnode->amt = amt;
+	gnode->group_addr = *group;
+	gnode->host_addr = *host;
+	gnode->family = family;
+	gnode->tunnel_list = tunnel;
+	gnode->filter_mode = MCAST_INCLUDE;
+	INIT_HLIST_NODE(&gnode->node);
+	INIT_DELAYED_WORK(&gnode->group_timer, amt_group_work);
+	for (i = 0; i < amt->hash_buckets; i++)
+		INIT_HLIST_HEAD(&gnode->sources[i]);
+
+	hash = amt_group_hash(tunnel, group);
+	hlist_add_head_rcu(&gnode->node, &tunnel->groups[hash]);
+	tunnel->nr_groups++;
+
+	if (gnode->family == ETH_P_IP)
+		netdev_dbg(amt->dev, "Join group %pI4\n",
+			   &gnode->group_addr.ip4);
+#if IS_ENABLED(CONFIG_IPV6)
+	else
+		netdev_dbg(amt->dev, "Join group %pI6\n",
+			   &gnode->group_addr.ip6);
+#endif
+
+	return gnode;
+}
+
+static struct sk_buff *amt_build_igmp_gq(struct amt_dev *amt)
+{
+	int hlen = LL_RESERVED_SPACE(amt->dev);
+	int tlen = amt->dev->needed_tailroom;
+	struct igmpv3_query *ihv3;
+	void *csum_start = NULL;
+	__sum16 *csum = NULL;
+	struct sk_buff *skb;
+	struct ethhdr *eth;
+	struct iphdr *iph;
+	unsigned int len;
+	int offset;
+
+	len = hlen + tlen + sizeof(*iph) + 4 + sizeof(*ihv3);
+	skb = netdev_alloc_skb_ip_align(amt->dev, len);
+	if (!skb)
+		return NULL;
+
+	skb_reserve(skb, hlen);
+	skb_push(skb, sizeof(*eth));
+	skb->protocol = htons(ETH_P_IP);
+	skb_reset_mac_header(skb);
+	skb->priority = TC_PRIO_CONTROL;
+	skb_put(skb, sizeof(*iph) + 4 + sizeof(*ihv3));
+	skb_pull(skb, sizeof(*eth));
+	skb_reset_network_header(skb);
+
+	iph		= ip_hdr(skb);
+	iph->version	= 4;
+	iph->ihl	= (sizeof(struct iphdr) + 4) >> 2;
+	iph->tos	= 0xc0;
+	iph->tot_len	= htons(sizeof(*iph) + 4 + sizeof(*ihv3));
+	iph->frag_off	= htons(IP_DF);
+	iph->ttl	= 1;
+	iph->id		= 0;
+	iph->protocol	= IPPROTO_IGMP;
+	iph->daddr	= htonl(INADDR_ALLHOSTS_GROUP);
+	iph->saddr	= htonl(INADDR_ANY);
+	((u8 *)&iph[1])[0] = IPOPT_RA;
+	((u8 *)&iph[1])[1] = 4;
+	((u8 *)&iph[1])[2] = 0;
+	((u8 *)&iph[1])[3] = 0;
+	ip_send_check(iph);
+
+	eth = eth_hdr(skb);
+	ether_addr_copy(eth->h_source, amt->dev->dev_addr);
+	ip_eth_mc_map(htonl(INADDR_ALLHOSTS_GROUP), eth->h_dest);
+	eth->h_proto = htons(ETH_P_IP);
+
+	ihv3		= skb_pull(skb, sizeof(*iph) + 4);
+	skb_reset_transport_header(skb);
+	ihv3->type	= IGMP_HOST_MEMBERSHIP_QUERY;
+	ihv3->code	= 1;
+	ihv3->group	= 0;
+	ihv3->qqic	= amt->qi;
+	ihv3->nsrcs	= 0;
+	ihv3->resv	= 0;
+	ihv3->suppress	= false;
+	ihv3->qrv	= amt->net->ipv4.sysctl_igmp_qrv;
+	ihv3->csum	= 0;
+	csum		= &ihv3->csum;
+	csum_start	= (void *)ihv3;
+	*csum		= ip_compute_csum(csum_start, sizeof(*ihv3));
+	offset		= skb_transport_offset(skb);
+	skb->csum	= skb_checksum(skb, offset, skb->len - offset, 0);
+	skb->ip_summed	= CHECKSUM_NONE;
+
+	skb_push(skb, sizeof(*eth) + sizeof(*iph) + 4);
+
+	return skb;
+}
+
+static void __amt_update_gw_status(struct amt_dev *amt, enum amt_status status,
+				   bool validate)
+{
+	if (validate && amt->status >= status)
+		return;
+	netdev_dbg(amt->dev, "Update GW status %s -> %s",
+		   status_str[amt->status], status_str[status]);
+	amt->status = status;
+}
+
+static void __amt_update_relay_status(struct amt_tunnel_list *tunnel,
+				      enum amt_status status,
+				      bool validate)
+{
+	if (validate && tunnel->status >= status)
+		return;
+	netdev_dbg(tunnel->amt->dev,
+		   "Update Tunnel(IP = %pI4, PORT = %u) status %s -> %s",
+		   &tunnel->ip4, ntohs(tunnel->source_port),
+		   status_str[tunnel->status], status_str[status]);
+	tunnel->status = status;
+}
+
+static void amt_update_gw_status(struct amt_dev *amt, enum amt_status status,
+				 bool validate)
+{
+	spin_lock_bh(&amt->lock);
+	__amt_update_gw_status(amt, status, validate);
+	spin_unlock_bh(&amt->lock);
+}
+
+static void amt_update_relay_status(struct amt_tunnel_list *tunnel, enum amt_status status,
+				    bool validate)
+{
+	spin_lock_bh(&tunnel->lock);
+	__amt_update_relay_status(tunnel, status, validate);
+	spin_unlock_bh(&tunnel->lock);
+}
+
+static void amt_send_discovery(struct amt_dev *amt)
+{
+	struct amt_header_discovery *amtd;
+	int hlen, tlen, offset;
+	struct socket *sock;
+	struct udphdr *udph;
+	struct sk_buff *skb;
+	struct iphdr *iph;
+	struct rtable *rt;
+	struct flowi4 fl4;
+	u32 len;
+	int err;
+
+	rcu_read_lock();
+	sock = rcu_dereference(amt->sock);
+	if (!sock)
+		goto out;
+
+	if (!netif_running(amt->stream_dev) || !netif_running(amt->dev))
+		goto out;
+
+	rt = ip_route_output_ports(amt->net, &fl4, sock->sk,
+				   amt->discovery_ip, amt->local_ip,
+				   amt->gw_port, amt->relay_port,
+				   IPPROTO_UDP, 0,
+				   amt->stream_dev->ifindex);
+	if (IS_ERR(rt)) {
+		amt->dev->stats.tx_errors++;
+		goto out;
+	}
+
+	hlen = LL_RESERVED_SPACE(amt->dev);
+	tlen = amt->dev->needed_tailroom;
+	len = hlen + tlen + sizeof(*iph) + sizeof(*udph) + sizeof(*amtd);
+	skb = netdev_alloc_skb_ip_align(amt->dev, len);
+	if (!skb) {
+		ip_rt_put(rt);
+		amt->dev->stats.tx_errors++;
+		goto out;
+	}
+
+	skb->priority = TC_PRIO_CONTROL;
+	skb_dst_set(skb, &rt->dst);
+
+	len = sizeof(*iph) + sizeof(*udph) + sizeof(*amtd);
+	skb_reset_network_header(skb);
+	skb_put(skb, len);
+	amtd = skb_pull(skb, sizeof(*iph) + sizeof(*udph));
+	amtd->version	= 0;
+	amtd->type	= AMT_MSG_DISCOVERY;
+	amtd->reserved	= 0;
+	amtd->nonce	= htonl(amt->nonce);
+	skb_push(skb, sizeof(*udph));
+	skb_reset_transport_header(skb);
+	udph		= udp_hdr(skb);
+	udph->source	= amt->gw_port;
+	udph->dest	= amt->relay_port;
+	udph->len	= htons(sizeof(*udph) + sizeof(*amtd));
+	udph->check	= 0;
+	offset = skb_transport_offset(skb);
+	skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
+	udph->check = csum_tcpudp_magic(amt->local_ip, amt->discovery_ip,
+					sizeof(*udph) + sizeof(*amtd),
+					IPPROTO_UDP, skb->csum);
+
+	skb_push(skb, sizeof(*iph));
+	iph		= ip_hdr(skb);
+	iph->version	= 4;
+	iph->ihl	= (sizeof(struct iphdr)) >> 2;
+	iph->tos	= 0xc0;
+	iph->frag_off	= 0;
+	iph->ttl	= ip4_dst_hoplimit(&rt->dst);
+	iph->daddr	= amt->discovery_ip;
+	iph->saddr	= amt->local_ip;
+	iph->protocol	= IPPROTO_UDP;
+	iph->tot_len	= htons(len);
+
+	skb->ip_summed = CHECKSUM_NONE;
+	ip_select_ident(amt->net, skb, NULL);
+	ip_send_check(iph);
+	err = ip_local_out(amt->net, sock->sk, skb);
+	if (unlikely(net_xmit_eval(err)))
+		amt->dev->stats.tx_errors++;
+
+	spin_lock_bh(&amt->lock);
+	__amt_update_gw_status(amt, AMT_STATUS_SENT_DISCOVERY, true);
+	spin_unlock_bh(&amt->lock);
+out:
+	rcu_read_unlock();
+}
+
+static void amt_send_request(struct amt_dev *amt, bool v6)
+{
+	struct amt_header_request *amtrh;
+	int hlen, tlen, offset;
+	struct socket *sock;
+	struct udphdr *udph;
+	struct sk_buff *skb;
+	struct iphdr *iph;
+	struct rtable *rt;
+	struct flowi4 fl4;
+	u32 len;
+	int err;
+
+	rcu_read_lock();
+	sock = rcu_dereference(amt->sock);
+	if (!sock)
+		goto out;
+
+	if (!netif_running(amt->stream_dev) || !netif_running(amt->dev))
+		goto out;
+
+	rt = ip_route_output_ports(amt->net, &fl4, sock->sk,
+				   amt->remote_ip, amt->local_ip,
+				   amt->gw_port, amt->relay_port,
+				   IPPROTO_UDP, 0,
+				   amt->stream_dev->ifindex);
+	if (IS_ERR(rt)) {
+		amt->dev->stats.tx_errors++;
+		goto out;
+	}
+
+	hlen = LL_RESERVED_SPACE(amt->dev);
+	tlen = amt->dev->needed_tailroom;
+	len = hlen + tlen + sizeof(*iph) + sizeof(*udph) + sizeof(*amtrh);
+	skb = netdev_alloc_skb_ip_align(amt->dev, len);
+	if (!skb) {
+		ip_rt_put(rt);
+		amt->dev->stats.tx_errors++;
+		goto out;
+	}
+
+	skb->priority = TC_PRIO_CONTROL;
+	skb_dst_set(skb, &rt->dst);
+
+	len = sizeof(*iph) + sizeof(*udph) + sizeof(*amtrh);
+	skb_reset_network_header(skb);
+	skb_put(skb, len);
+	amtrh = skb_pull(skb, sizeof(*iph) + sizeof(*udph));
+	amtrh->version	 = 0;
+	amtrh->type	 = AMT_MSG_REQUEST;
+	amtrh->reserved1 = 0;
+	amtrh->p	 = v6;
+	amtrh->reserved2 = 0;
+	amtrh->nonce	 = htonl(amt->nonce);
+	skb_push(skb, sizeof(*udph));
+	skb_reset_transport_header(skb);
+	udph		= udp_hdr(skb);
+	udph->source	= amt->gw_port;
+	udph->dest	= amt->relay_port;
+	udph->len	= htons(sizeof(*amtrh) + sizeof(*udph));
+	udph->check	= 0;
+	offset = skb_transport_offset(skb);
+	skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
+	udph->check = csum_tcpudp_magic(amt->local_ip, amt->remote_ip,
+					sizeof(*udph) + sizeof(*amtrh),
+					IPPROTO_UDP, skb->csum);
+
+	skb_push(skb, sizeof(*iph));
+	iph		= ip_hdr(skb);
+	iph->version	= 4;
+	iph->ihl	= (sizeof(struct iphdr)) >> 2;
+	iph->tos	= 0xc0;
+	iph->frag_off	= 0;
+	iph->ttl	= ip4_dst_hoplimit(&rt->dst);
+	iph->daddr	= amt->remote_ip;
+	iph->saddr	= amt->local_ip;
+	iph->protocol	= IPPROTO_UDP;
+	iph->tot_len	= htons(len);
+
+	skb->ip_summed = CHECKSUM_NONE;
+	ip_select_ident(amt->net, skb, NULL);
+	ip_send_check(iph);
+	err = ip_local_out(amt->net, sock->sk, skb);
+	if (unlikely(net_xmit_eval(err)))
+		amt->dev->stats.tx_errors++;
+
+out:
+	rcu_read_unlock();
+}
+
+static void amt_send_igmp_gq(struct amt_dev *amt,
+			     struct amt_tunnel_list *tunnel)
+{
+	struct sk_buff *skb;
+
+	skb = amt_build_igmp_gq(amt);
+	if (!skb)
+		return;
+
+	amt_skb_cb(skb)->tunnel = tunnel;
+	dev_queue_xmit(skb);
+}
+
+#if IS_ENABLED(CONFIG_IPV6)
+static struct sk_buff *amt_build_mld_gq(struct amt_dev *amt)
+{
+	u8 ra[8] = { IPPROTO_ICMPV6, 0, IPV6_TLV_ROUTERALERT,
+		     2, 0, 0, IPV6_TLV_PAD1, IPV6_TLV_PAD1 };
+	int hlen = LL_RESERVED_SPACE(amt->dev);
+	int tlen = amt->dev->needed_tailroom;
+	struct mld2_query *mld2q;
+	void *csum_start = NULL;
+	struct ipv6hdr *ip6h;
+	__sum16 *csum = NULL;
+	struct sk_buff *skb;
+	struct ethhdr *eth;
+	u8 *hopopt;
+	u32 len;
+
+	len = hlen + tlen + sizeof(*ip6h) + sizeof(ra) + sizeof(*mld2q);
+	skb = netdev_alloc_skb_ip_align(amt->dev, len);
+	if (!skb)
+		return NULL;
+
+	skb_reserve(skb, hlen);
+	skb_push(skb, sizeof(*eth));
+	skb_reset_mac_header(skb);
+	eth = eth_hdr(skb);
+	skb->priority = TC_PRIO_CONTROL;
+	skb->protocol = htons(ETH_P_IPV6);
+	skb_put_zero(skb, sizeof(*ip6h) + sizeof(ra) + sizeof(*mld2q));
+	skb_pull(skb, sizeof(*eth));
+	skb_reset_network_header(skb);
+	ip6h			= ipv6_hdr(skb);
+	ip6h->payload_len	= htons(sizeof(ra) + sizeof(*mld2q));
+	ip6h->nexthdr		= NEXTHDR_HOP;
+	ip6h->hop_limit		= 1;
+	ip6h->daddr		= mld2_all_node;
+	ip6_flow_hdr(ip6h, 0, 0);
+	hopopt = (u8 *)(ip6h + 1);
+	hopopt[0] = IPPROTO_ICMPV6;             /* next hdr */
+	hopopt[1] = 0;                          /* length of HbH */
+	hopopt[2] = IPV6_TLV_ROUTERALERT;       /* Router Alert */
+	hopopt[3] = 2;                          /* Length of RA Option */
+	hopopt[4] = 0;                          /* Type = 0x0000 (MLD) */
+	hopopt[5] = 0;
+	hopopt[6] = IPV6_TLV_PAD1;              /* Pad1 */
+	hopopt[7] = IPV6_TLV_PAD1;              /* Pad1 */
+
+	if (ipv6_dev_get_saddr(amt->net, amt->dev, &ip6h->daddr, 0, &ip6h->saddr)) {
+		amt->dev->stats.tx_errors++;
+		kfree_skb(skb);
+		return NULL;
+	}
+
+	eth->h_proto = htons(ETH_P_IPV6);
+	ether_addr_copy(eth->h_source, amt->dev->dev_addr);
+	ipv6_eth_mc_map(&mld2_all_node, eth->h_dest);
+
+	skb_pull(skb, sizeof(*ip6h) + sizeof(ra));
+	skb_reset_transport_header(skb);
+	mld2q			= (struct mld2_query *)icmp6_hdr(skb);
+	mld2q->mld2q_mrc	= htons(1);
+	mld2q->mld2q_type	= ICMPV6_MGM_QUERY;
+	mld2q->mld2q_code	= 0;
+	mld2q->mld2q_cksum	= 0;
+	mld2q->mld2q_resv1	= 0;
+	mld2q->mld2q_resv2	= 0;
+	mld2q->mld2q_suppress	= 0;
+	mld2q->mld2q_qrv	= amt->qrv;
+	mld2q->mld2q_nsrcs	= 0;
+	mld2q->mld2q_qqic	= amt->qi;
+	csum			= &mld2q->mld2q_cksum;
+	csum_start		= (void *)mld2q;
+	mld2q->mld2q_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
+					     sizeof(*mld2q),
+					     IPPROTO_ICMPV6,
+					     csum_partial(csum_start,
+							  sizeof(*mld2q), 0));
+
+	skb->ip_summed = CHECKSUM_NONE;
+	skb_push(skb, sizeof(*eth) + sizeof(*ip6h) + sizeof(ra));
+	return skb;
+}
+
+static void amt_send_mld_gq(struct amt_dev *amt, struct amt_tunnel_list *tunnel)
+{
+	struct sk_buff *skb;
+
+	skb = amt_build_mld_gq(amt);
+	if (!skb)
+		return;
+
+	amt_skb_cb(skb)->tunnel = tunnel;
+	dev_queue_xmit(skb);
+}
+#else
+static void amt_send_mld_gq(struct amt_dev *amt, struct amt_tunnel_list *tunnel)
+{
+}
+#endif
+
+static void amt_secret_work(struct work_struct *work)
+{
+	struct amt_dev *amt = container_of(to_delayed_work(work),
+					   struct amt_dev,
+					   secret_wq);
+
+	spin_lock_bh(&amt->lock);
+	get_random_bytes(&amt->key, sizeof(siphash_key_t));
+	spin_unlock_bh(&amt->lock);
+	mod_delayed_work(amt_wq, &amt->secret_wq,
+			 msecs_to_jiffies(AMT_SECRET_TIMEOUT));
+}
+
+static void amt_discovery_work(struct work_struct *work)
+{
+	struct amt_dev *amt = container_of(to_delayed_work(work),
+					   struct amt_dev,
+					   discovery_wq);
+
+	spin_lock_bh(&amt->lock);
+	if (amt->status > AMT_STATUS_SENT_DISCOVERY)
+		goto out;
+	get_random_bytes(&amt->nonce, sizeof(u32));
+	spin_unlock_bh(&amt->lock);
+
+	amt_send_discovery(amt);
+	spin_lock_bh(&amt->lock);
+out:
+	mod_delayed_work(amt_wq, &amt->discovery_wq,
+			 msecs_to_jiffies(AMT_DISCOVERY_TIMEOUT));
+	spin_unlock_bh(&amt->lock);
+}
+
+static void amt_req_work(struct work_struct *work)
+{
+	struct amt_dev *amt = container_of(to_delayed_work(work),
+					   struct amt_dev,
+					   req_wq);
+	u32 exp;
+
+	spin_lock_bh(&amt->lock);
+	if (amt->status < AMT_STATUS_RECEIVED_ADVERTISEMENT)
+		goto out;
+
+	if (amt->req_cnt++ > AMT_MAX_REQ_COUNT) {
+		netdev_dbg(amt->dev, "Gateway is not ready");
+		amt->qi = AMT_INIT_REQ_TIMEOUT;
+		amt->ready4 = false;
+		amt->ready6 = false;
+		amt->remote_ip = 0;
+		__amt_update_gw_status(amt, AMT_STATUS_INIT, false);
+		amt->req_cnt = 0;
+	}
+	spin_unlock_bh(&amt->lock);
+
+	amt_send_request(amt, false);
+	amt_send_request(amt, true);
+	amt_update_gw_status(amt, AMT_STATUS_SENT_REQUEST, true);
+	spin_lock_bh(&amt->lock);
+out:
+	exp = min_t(u32, (1 * (1 << amt->req_cnt)), AMT_MAX_REQ_TIMEOUT);
+	mod_delayed_work(amt_wq, &amt->req_wq, msecs_to_jiffies(exp * 1000));
+	spin_unlock_bh(&amt->lock);
+}
+
+static bool amt_send_membership_update(struct amt_dev *amt,
+				       struct sk_buff *skb,
+				       bool v6)
+{
+	struct amt_header_membership_update *amtmu;
+	struct socket *sock;
+	struct iphdr *iph;
+	struct flowi4 fl4;
+	struct rtable *rt;
+	int err;
+
+	sock = rcu_dereference(amt->sock);
+	if (!sock)
+		return true;
+
+	err = skb_cow_head(skb, LL_RESERVED_SPACE(amt->dev) + sizeof(*amtmu) +
+			   sizeof(*iph) + sizeof(struct udphdr));
+	if (err)
+		return true;
+
+	skb_reset_inner_headers(skb);
+	memset(&fl4, 0, sizeof(struct flowi4));
+	fl4.flowi4_oif         = amt->stream_dev->ifindex;
+	fl4.daddr              = amt->remote_ip;
+	fl4.saddr              = amt->local_ip;
+	fl4.flowi4_tos         = 0xc0;
+	fl4.flowi4_proto       = IPPROTO_UDP;
+	rt = ip_route_output_key(amt->net, &fl4);
+	if (IS_ERR(rt)) {
+		netdev_dbg(amt->dev, "no route to %pI4\n", &amt->remote_ip);
+		return true;
+	}
+
+	amtmu			= skb_push(skb, sizeof(*amtmu));
+	amtmu->version		= 0;
+	amtmu->type		= AMT_MSG_MEMBERSHIP_UPDATE;
+	amtmu->reserved		= 0;
+	amtmu->nonce		= htonl(amt->nonce);
+	amtmu->response_mac	= amt->mac;
+
+	if (!v6)
+		skb_set_inner_protocol(skb, htons(ETH_P_IP));
+	else
+		skb_set_inner_protocol(skb, htons(ETH_P_IPV6));
+	udp_tunnel_xmit_skb(rt, sock->sk, skb,
+			    fl4.saddr,
+			    fl4.daddr,
+			    0xc0,
+			    ip4_dst_hoplimit(&rt->dst),
+			    0,
+			    amt->gw_port,
+			    amt->relay_port,
+			    false,
+			    false);
+	amt_update_gw_status(amt, AMT_STATUS_SENT_UPDATE, true);
+	return false;
+}
+
+static void amt_send_multicast_data(struct amt_dev *amt,
+				    const struct sk_buff *oskb,
+				    struct amt_tunnel_list *tunnel,
+				    bool v6)
+{
+	struct amt_header_mcast_data *amtmd;
+	struct socket *sock;
+	struct sk_buff *skb;
+	struct iphdr *iph;
+	struct flowi4 fl4;
+	struct rtable *rt;
+
+	sock = rcu_dereference(amt->sock);
+	if (!sock)
+		return;
+
+	skb = skb_copy_expand(oskb, sizeof(*amtmd) + sizeof(*iph) +
+			      sizeof(struct udphdr), 0, GFP_ATOMIC);
+	if (!skb)
+		return;
+
+	skb_reset_inner_headers(skb);
+	memset(&fl4, 0, sizeof(struct flowi4));
+	fl4.flowi4_oif         = amt->stream_dev->ifindex;
+	fl4.daddr              = tunnel->ip4;
+	fl4.saddr              = amt->local_ip;
+	fl4.flowi4_proto       = IPPROTO_UDP;
+	rt = ip_route_output_key(amt->net, &fl4);
+	if (IS_ERR(rt)) {
+		netdev_dbg(amt->dev, "no route to %pI4\n", &tunnel->ip4);
+		kfree_skb(skb);
+		return;
+	}
+
+	amtmd = skb_push(skb, sizeof(*amtmd));
+	amtmd->version = 0;
+	amtmd->reserved = 0;
+	amtmd->type = AMT_MSG_MULTICAST_DATA;
+
+	if (!v6)
+		skb_set_inner_protocol(skb, htons(ETH_P_IP));
+	else
+		skb_set_inner_protocol(skb, htons(ETH_P_IPV6));
+	udp_tunnel_xmit_skb(rt, sock->sk, skb,
+			    fl4.saddr,
+			    fl4.daddr,
+			    0xc0,
+			    ip4_dst_hoplimit(&rt->dst),
+			    0,
+			    amt->relay_port,
+			    tunnel->source_port,
+			    false,
+			    false);
+}
+
+static bool amt_send_membership_query(struct amt_dev *amt,
+				      struct sk_buff *skb,
+				      struct amt_tunnel_list *tunnel,
+				      bool v6)
+{
+	struct amt_header_membership_query *amtmq;
+	struct socket *sock;
+	struct rtable *rt;
+	struct flowi4 fl4;
+	int err;
+
+	sock = rcu_dereference(amt->sock);
+	if (!sock)
+		return true;
+
+	err = skb_cow_head(skb, LL_RESERVED_SPACE(amt->dev) + sizeof(*amtmq) +
+			   sizeof(struct iphdr) + sizeof(struct udphdr));
+	if (err)
+		return true;
+
+	skb_reset_inner_headers(skb);
+	memset(&fl4, 0, sizeof(struct flowi4));
+	fl4.flowi4_oif         = amt->stream_dev->ifindex;
+	fl4.daddr              = tunnel->ip4;
+	fl4.saddr              = amt->local_ip;
+	fl4.flowi4_tos         = 0xc0;
+	fl4.flowi4_proto       = IPPROTO_UDP;
+	rt = ip_route_output_key(amt->net, &fl4);
+	if (IS_ERR(rt)) {
+		netdev_dbg(amt->dev, "no route to %pI4\n", &tunnel->ip4);
+		return -1;
+	}
+
+	amtmq		= skb_push(skb, sizeof(*amtmq));
+	amtmq->version	= 0;
+	amtmq->type	= AMT_MSG_MEMBERSHIP_QUERY;
+	amtmq->reserved = 0;
+	amtmq->l	= 0;
+	amtmq->g	= 0;
+	amtmq->nonce	= tunnel->nonce;
+	amtmq->response_mac = tunnel->mac;
+
+	if (!v6)
+		skb_set_inner_protocol(skb, htons(ETH_P_IP));
+	else
+		skb_set_inner_protocol(skb, htons(ETH_P_IPV6));
+	udp_tunnel_xmit_skb(rt, sock->sk, skb,
+			    fl4.saddr,
+			    fl4.daddr,
+			    0xc0,
+			    ip4_dst_hoplimit(&rt->dst),
+			    0,
+			    amt->relay_port,
+			    tunnel->source_port,
+			    false,
+			    false);
+	amt_update_relay_status(tunnel, AMT_STATUS_SENT_QUERY, true);
+	return false;
+}
+
+static netdev_tx_t amt_dev_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct amt_dev *amt = netdev_priv(dev);
+	struct amt_tunnel_list *tunnel;
+	struct amt_group_node *gnode;
+	union amt_addr group = {0,};
+#if IS_ENABLED(CONFIG_IPV6)
+	struct ipv6hdr *ip6h;
+	struct mld_msg *mld;
+#endif
+	bool report = false;
+	struct igmphdr *ih;
+	bool query = false;
+	struct iphdr *iph;
+	bool data = false;
+	bool v6 = false;
+	u32 hash;
+
+	rcu_read_lock();
+	iph = ip_hdr(skb);
+	if (iph->version == 4) {
+		if (!ipv4_is_multicast(iph->daddr))
+			goto free;
+
+		if (!ip_mc_check_igmp(skb)) {
+			ih = igmp_hdr(skb);
+			switch (ih->type) {
+			case IGMPV3_HOST_MEMBERSHIP_REPORT:
+			case IGMP_HOST_MEMBERSHIP_REPORT:
+				report = true;
+				break;
+			case IGMP_HOST_MEMBERSHIP_QUERY:
+				query = true;
+				break;
+			default:
+				goto free;
+			}
+		} else {
+			data = true;
+		}
+		v6 = false;
+		group.ip4 = iph->daddr;
+#if IS_ENABLED(CONFIG_IPV6)
+	} else if (iph->version == 6) {
+		ip6h = ipv6_hdr(skb);
+		if (!ipv6_addr_is_multicast(&ip6h->daddr))
+			goto free;
+
+		if (!ipv6_mc_check_mld(skb)) {
+			mld = (struct mld_msg *)skb_transport_header(skb);
+			switch (mld->mld_type) {
+			case ICMPV6_MGM_REPORT:
+			case ICMPV6_MLD2_REPORT:
+				report = true;
+				break;
+			case ICMPV6_MGM_QUERY:
+				query = true;
+				break;
+			default:
+				goto free;
+			}
+		} else {
+			data = true;
+		}
+		v6 = true;
+		group.ip6 = ip6h->daddr;
+#endif
+	} else {
+		dev->stats.tx_errors++;
+		goto free;
+	}
+
+	if (!pskb_may_pull(skb, sizeof(struct ethhdr)))
+		goto free;
+
+	skb_pull(skb, sizeof(struct ethhdr));
+
+	if (amt->mode == AMT_MODE_GATEWAY) {
+		/* Gateway only passes IGMP/MLD packets */
+		if (!report)
+			goto free;
+		if ((!v6 && !amt->ready4) || (v6 && !amt->ready6))
+			goto free;
+		if (amt_send_membership_update(amt, skb,  v6))
+			goto free;
+		goto unlock;
+	} else if (amt->mode == AMT_MODE_RELAY) {
+		if (query) {
+			tunnel = amt_skb_cb(skb)->tunnel;
+			if (!tunnel) {
+				WARN_ON(1);
+				goto free;
+			}
+
+			/* Do not forward unexpected query */
+			if (amt_send_membership_query(amt, skb, tunnel, v6))
+				goto free;
+			goto unlock;
+		}
+
+		if (!data)
+			goto free;
+		list_for_each_entry_rcu(tunnel, &amt->tunnel_list, list) {
+			hash = amt_group_hash(tunnel, &group);
+			hlist_for_each_entry_rcu(gnode, &tunnel->groups[hash], node) {
+				if (!v6) {
+					if (gnode->group_addr.ip4 == iph->daddr)
+						goto found;
+#if IS_ENABLED(CONFIG_IPV6)
+				} else {
+					if (ipv6_addr_equal(&gnode->group_addr.ip6,
+							    &ip6h->daddr))
+						goto found;
+#endif
+				}
+			}
+			continue;
+found:;
+			amt_send_multicast_data(amt, skb, tunnel, v6);
+		}
+	}
+
+	dev_kfree_skb(skb);
+	rcu_read_unlock();
+	return NETDEV_TX_OK;
+free:
+	dev_kfree_skb(skb);
+unlock:
+	rcu_read_unlock();
+	dev->stats.tx_dropped++;
+	return NETDEV_TX_OK;
+}
+
+static int amt_parse_type(struct sk_buff *skb)
+{
+	struct amt_header *amth;
+
+	if (!pskb_may_pull(skb, sizeof(struct udphdr) +
+			   sizeof(struct amt_header)))
+		return -1;
+
+	amth = (struct amt_header *)(udp_hdr(skb) + 1);
+
+	if (amth->version != 0)
+		return -1;
+
+	if (amth->type >= __AMT_MSG_MAX || !amth->type)
+		return -1;
+	return amth->type;
+}
+
+static void amt_clear_groups(struct amt_tunnel_list *tunnel)
+{
+	struct amt_dev *amt = tunnel->amt;
+	struct amt_group_node *gnode;
+	struct hlist_node *t;
+	int i;
+
+	spin_lock_bh(&tunnel->lock);
+	rcu_read_lock();
+	for (i = 0; i < amt->hash_buckets; i++)
+		hlist_for_each_entry_safe(gnode, t, &tunnel->groups[i], node)
+			amt_del_group(amt, gnode);
+	rcu_read_unlock();
+	spin_unlock_bh(&tunnel->lock);
+}
+
+static void amt_tunnel_expire(struct work_struct *work)
+{
+	struct amt_tunnel_list *tunnel = container_of(to_delayed_work(work),
+						      struct amt_tunnel_list,
+						      gc_wq);
+	struct amt_dev *amt = tunnel->amt;
+
+	spin_lock_bh(&amt->lock);
+	rcu_read_lock();
+	list_del_rcu(&tunnel->list);
+	amt->nr_tunnels--;
+	amt_clear_groups(tunnel);
+	rcu_read_unlock();
+	spin_unlock_bh(&amt->lock);
+	kfree_rcu(tunnel, rcu);
+}
+
+static struct socket *amt_create_sock(struct net *net, __be16 port)
+{
+	struct udp_port_cfg udp_conf;
+	struct socket *sock;
+	int err;
+
+	memset(&udp_conf, 0, sizeof(udp_conf));
+	udp_conf.family = AF_INET;
+	udp_conf.local_ip.s_addr = htonl(INADDR_ANY);
+
+	udp_conf.local_udp_port = port;
+
+	err = udp_sock_create(net, &udp_conf, &sock);
+	if (err < 0)
+		return ERR_PTR(err);
+
+	return sock;
+}
+
+static void amt_cleanup_srcs(struct amt_dev *amt,
+			     struct amt_tunnel_list *tunnel,
+			     struct amt_group_node *gnode)
+{
+	struct amt_source_node *snode;
+	struct hlist_node *t;
+	int i;
+
+	/* Delete old sources */
+	for (i = 0; i < amt->hash_buckets; i++) {
+		hlist_for_each_entry_safe(snode, t, &gnode->sources[i], node) {
+			if (snode->flags == AMT_SOURCE_OLD)
+				amt_destroy_source(snode);
+		}
+	}
+
+	/* switch from new to old */
+	for (i = 0; i < amt->hash_buckets; i++)  {
+		hlist_for_each_entry_rcu(snode, &gnode->sources[i], node) {
+			snode->flags = AMT_SOURCE_OLD;
+			if (gnode->family == ETH_P_IP)
+				netdev_dbg(snode->gnode->amt->dev,
+					   "Add source as OLD %pI4 from %pI4\n",
+					   &snode->source_addr.ip4,
+					   &gnode->group_addr.ip4);
+#if IS_ENABLED(CONFIG_IPV6)
+			else
+				netdev_dbg(snode->gnode->amt->dev,
+					   "Add source as OLD %pI6 from %pI6\n",
+					   &snode->source_addr.ip6,
+					   &gnode->group_addr.ip6);
+#endif
+		}
+	}
+}
+
+static void amt_add_srcs(struct amt_dev *amt, struct amt_tunnel_list *tunnel,
+			 struct amt_group_node *gnode, void *grec,
+			 bool v6)
+{
+	struct igmpv3_grec *igmp_grec;
+	struct amt_source_node *snode;
+#if IS_ENABLED(CONFIG_IPV6)
+	struct mld2_grec *mld_grec;
+#endif
+	union amt_addr src = {0,};
+	u16 nsrcs;
+	u32 hash;
+	int i;
+
+	if (!v6) {
+		igmp_grec = (struct igmpv3_grec *)grec;
+		nsrcs = ntohs(igmp_grec->grec_nsrcs);
+	} else {
+#if IS_ENABLED(CONFIG_IPV6)
+		mld_grec = (struct mld2_grec *)grec;
+		nsrcs = ntohs(mld_grec->grec_nsrcs);
+#else
+	return;
+#endif
+	}
+	for (i = 0; i < nsrcs; i++) {
+		if (tunnel->nr_sources >= amt->max_sources)
+			return;
+		if (!v6)
+			src.ip4 = igmp_grec->grec_src[i];
+#if IS_ENABLED(CONFIG_IPV6)
+		else
+			memcpy(&src.ip6, &mld_grec->grec_src[i],
+			       sizeof(struct in6_addr));
+#endif
+		if (amt_lookup_src(tunnel, gnode, AMT_FILTER_ALL, &src))
+			continue;
+
+		snode = amt_alloc_snode(gnode, &src);
+		if (snode) {
+			hash = amt_source_hash(tunnel, &snode->source_addr);
+			hlist_add_head_rcu(&snode->node, &gnode->sources[hash]);
+			tunnel->nr_sources++;
+			gnode->nr_sources++;
+
+			if (gnode->family == ETH_P_IP)
+				netdev_dbg(snode->gnode->amt->dev,
+					   "Add source as NEW %pI4 from %pI4\n",
+					   &snode->source_addr.ip4,
+					   &gnode->group_addr.ip4);
+#if IS_ENABLED(CONFIG_IPV6)
+			else
+				netdev_dbg(snode->gnode->amt->dev,
+					   "Add source as NEW %pI6 from %pI6\n",
+					   &snode->source_addr.ip6,
+					   &gnode->group_addr.ip6);
+#endif
+		}
+	}
+}
+
+/* Router State   Report Rec'd New Router State
+ * ------------   ------------ ----------------
+ * EXCLUDE (X,Y)  IS_IN (A)    EXCLUDE (X+A,Y-A)
+ *
+ * -----------+-----------+-----------+
+ *            |    OLD    |    NEW    |
+ * -----------+-----------+-----------+
+ *    FWD     |     X     |    X+A    |
+ * -----------+-----------+-----------+
+ *    D_FWD   |     Y     |    Y-A    |
+ * -----------+-----------+-----------+
+ *    NONE    |           |     A     |
+ * -----------+-----------+-----------+
+ *
+ * a) Received sources are NONE/NEW
+ * b) All NONE will be deleted by amt_cleanup_srcs().
+ * c) All OLD will be deleted by amt_cleanup_srcs().
+ * d) After delete, NEW source will be switched to OLD.
+ */
+static void amt_lookup_act_srcs(struct amt_tunnel_list *tunnel,
+				struct amt_group_node *gnode,
+				void *grec,
+				enum amt_ops ops,
+				enum amt_filter filter,
+				enum amt_act act,
+				bool v6)
+{
+	struct amt_dev *amt = tunnel->amt;
+	struct amt_source_node *snode;
+	struct igmpv3_grec *igmp_grec;
+#if IS_ENABLED(CONFIG_IPV6)
+	struct mld2_grec *mld_grec;
+#endif
+	union amt_addr src = {0,};
+	struct hlist_node *t;
+	u16 nsrcs;
+	int i, j;
+
+	if (!v6) {
+		igmp_grec = (struct igmpv3_grec *)grec;
+		nsrcs = ntohs(igmp_grec->grec_nsrcs);
+	} else {
+#if IS_ENABLED(CONFIG_IPV6)
+		mld_grec = (struct mld2_grec *)grec;
+		nsrcs = ntohs(mld_grec->grec_nsrcs);
+#else
+	return;
+#endif
+	}
+
+	memset(&src, 0, sizeof(union amt_addr));
+	switch (ops) {
+	case AMT_OPS_INT:
+		/* A*B */
+		for (i = 0; i < nsrcs; i++) {
+			if (!v6)
+				src.ip4 = igmp_grec->grec_src[i];
+#if IS_ENABLED(CONFIG_IPV6)
+			else
+				memcpy(&src.ip6, &mld_grec->grec_src[i],
+				       sizeof(struct in6_addr));
+#endif
+			snode = amt_lookup_src(tunnel, gnode, filter, &src);
+			if (!snode)
+				continue;
+			amt_act_src(tunnel, gnode, snode, act);
+		}
+		break;
+	case AMT_OPS_UNI:
+		/* A+B */
+		for (i = 0; i < amt->hash_buckets; i++) {
+			hlist_for_each_entry_safe(snode, t, &gnode->sources[i],
+						  node) {
+				if (amt_status_filter(snode, filter))
+					amt_act_src(tunnel, gnode, snode, act);
+			}
+		}
+		for (i = 0; i < nsrcs; i++) {
+			if (!v6)
+				src.ip4 = igmp_grec->grec_src[i];
+#if IS_ENABLED(CONFIG_IPV6)
+			else
+				memcpy(&src.ip6, &mld_grec->grec_src[i],
+				       sizeof(struct in6_addr));
+#endif
+			snode = amt_lookup_src(tunnel, gnode, filter, &src);
+			if (!snode)
+				continue;
+			amt_act_src(tunnel, gnode, snode, act);
+		}
+		break;
+	case AMT_OPS_SUB:
+		/* A-B */
+		for (i = 0; i < amt->hash_buckets; i++) {
+			hlist_for_each_entry_safe(snode, t, &gnode->sources[i],
+						  node) {
+				if (!amt_status_filter(snode, filter))
+					continue;
+				for (j = 0; j < nsrcs; j++) {
+					if (!v6)
+						src.ip4 = igmp_grec->grec_src[j];
+#if IS_ENABLED(CONFIG_IPV6)
+					else
+						memcpy(&src.ip6,
+						       &mld_grec->grec_src[j],
+						       sizeof(struct in6_addr));
+#endif
+					if (amt_addr_equal(&snode->source_addr,
+							   &src))
+						goto out_sub;
+				}
+				amt_act_src(tunnel, gnode, snode, act);
+				continue;
+out_sub:;
+			}
+		}
+		break;
+	case AMT_OPS_SUB_REV:
+		/* B-A */
+		for (i = 0; i < nsrcs; i++) {
+			if (!v6)
+				src.ip4 = igmp_grec->grec_src[i];
+#if IS_ENABLED(CONFIG_IPV6)
+			else
+				memcpy(&src.ip6, &mld_grec->grec_src[i],
+				       sizeof(struct in6_addr));
+#endif
+			snode = amt_lookup_src(tunnel, gnode, AMT_FILTER_ALL,
+					       &src);
+			if (!snode) {
+				snode = amt_lookup_src(tunnel, gnode,
+						       filter, &src);
+				if (snode)
+					amt_act_src(tunnel, gnode, snode, act);
+			}
+		}
+		break;
+	default:
+		netdev_dbg(amt->dev, "Invalid type\n");
+		return;
+	}
+}
+
+static void amt_mcast_is_in_handler(struct amt_dev *amt,
+				    struct amt_tunnel_list *tunnel,
+				    struct amt_group_node *gnode,
+				    void *grec, void *zero_grec, bool v6)
+{
+	if (gnode->filter_mode == MCAST_INCLUDE) {
+/* Router State   Report Rec'd New Router State        Actions
+ * ------------   ------------ ----------------        -------
+ * INCLUDE (A)    IS_IN (B)    INCLUDE (A+B)           (B)=GMI
+ */
+		/* Update IS_IN (B) as FWD/NEW */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_UNI,
+				    AMT_FILTER_NONE_NEW,
+				    AMT_ACT_STATUS_FWD_NEW,
+				    v6);
+		/* Update INCLUDE (A) as NEW */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_UNI,
+				    AMT_FILTER_FWD,
+				    AMT_ACT_STATUS_FWD_NEW,
+				    v6);
+		/* (B)=GMI */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_INT,
+				    AMT_FILTER_FWD_NEW,
+				    AMT_ACT_GMI,
+				    v6);
+	} else {
+/* State        Actions
+ * ------------   ------------ ----------------        -------
+ * EXCLUDE (X,Y)  IS_IN (A)    EXCLUDE (X+A,Y-A)       (A)=GMI
+ */
+		/* Update (A) in (X, Y) as NONE/NEW */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_INT,
+				    AMT_FILTER_BOTH,
+				    AMT_ACT_STATUS_NONE_NEW,
+				    v6);
+		/* Update FWD/OLD as FWD/NEW */
+		amt_lookup_act_srcs(tunnel, gnode, zero_grec, AMT_OPS_UNI,
+				    AMT_FILTER_FWD,
+				    AMT_ACT_STATUS_FWD_NEW,
+				    v6);
+		/* Update IS_IN (A) as FWD/NEW */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_INT,
+				    AMT_FILTER_NONE_NEW,
+				    AMT_ACT_STATUS_FWD_NEW,
+				    v6);
+		/* Update EXCLUDE (, Y-A) as D_FWD_NEW */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_SUB,
+				    AMT_FILTER_D_FWD,
+				    AMT_ACT_STATUS_D_FWD_NEW,
+				    v6);
+	}
+}
+
+static void amt_mcast_is_ex_handler(struct amt_dev *amt,
+				    struct amt_tunnel_list *tunnel,
+				    struct amt_group_node *gnode,
+				    void *grec, void *zero_grec, bool v6)
+{
+	if (gnode->filter_mode == MCAST_INCLUDE) {
+/* Router State   Report Rec'd  New Router State         Actions
+ * ------------   ------------  ----------------         -------
+ * INCLUDE (A)    IS_EX (B)     EXCLUDE (A*B,B-A)        (B-A)=0
+ *                                                       Delete (A-B)
+ *                                                       Group Timer=GMI
+ */
+		/* EXCLUDE(A*B, ) */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_INT,
+				    AMT_FILTER_FWD,
+				    AMT_ACT_STATUS_FWD_NEW,
+				    v6);
+		/* EXCLUDE(, B-A) */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_SUB_REV,
+				    AMT_FILTER_FWD,
+				    AMT_ACT_STATUS_D_FWD_NEW,
+				    v6);
+		/* (B-A)=0 */
+		amt_lookup_act_srcs(tunnel, gnode, zero_grec, AMT_OPS_UNI,
+				    AMT_FILTER_D_FWD_NEW,
+				    AMT_ACT_GMI_ZERO,
+				    v6);
+		/* Group Timer=GMI */
+		if (!mod_delayed_work(amt_wq, &gnode->group_timer,
+				      msecs_to_jiffies(amt_gmi(amt))))
+			dev_hold(amt->dev);
+		gnode->filter_mode = MCAST_EXCLUDE;
+		/* Delete (A-B) will be worked by amt_cleanup_srcs(). */
+	} else {
+/* Router State   Report Rec'd  New Router State	Actions
+ * ------------   ------------  ----------------	-------
+ * EXCLUDE (X,Y)  IS_EX (A)     EXCLUDE (A-Y,Y*A)	(A-X-Y)=GMI
+ *							Delete (X-A)
+ *							Delete (Y-A)
+ *							Group Timer=GMI
+ */
+		/* EXCLUDE (A-Y, ) */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_SUB_REV,
+				    AMT_FILTER_D_FWD,
+				    AMT_ACT_STATUS_FWD_NEW,
+				    v6);
+		/* EXCLUDE (, Y*A ) */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_INT,
+				    AMT_FILTER_D_FWD,
+				    AMT_ACT_STATUS_D_FWD_NEW,
+				    v6);
+		/* (A-X-Y)=GMI */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_SUB_REV,
+				    AMT_FILTER_BOTH_NEW,
+				    AMT_ACT_GMI,
+				    v6);
+		/* Group Timer=GMI */
+		if (!mod_delayed_work(amt_wq, &gnode->group_timer,
+				      msecs_to_jiffies(amt_gmi(amt))))
+			dev_hold(amt->dev);
+		/* Delete (X-A), (Y-A) will be worked by amt_cleanup_srcs(). */
+	}
+}
+
+static void amt_mcast_to_in_handler(struct amt_dev *amt,
+				    struct amt_tunnel_list *tunnel,
+				    struct amt_group_node *gnode,
+				    void *grec, void *zero_grec, bool v6)
+{
+	if (gnode->filter_mode == MCAST_INCLUDE) {
+/* Router State   Report Rec'd New Router State        Actions
+ * ------------   ------------ ----------------        -------
+ * INCLUDE (A)    TO_IN (B)    INCLUDE (A+B)           (B)=GMI
+ *						       Send Q(G,A-B)
+ */
+		/* Update TO_IN (B) sources as FWD/NEW */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_UNI,
+				    AMT_FILTER_NONE_NEW,
+				    AMT_ACT_STATUS_FWD_NEW,
+				    v6);
+		/* Update INCLUDE (A) sources as NEW */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_UNI,
+				    AMT_FILTER_FWD,
+				    AMT_ACT_STATUS_FWD_NEW,
+				    v6);
+		/* (B)=GMI */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_INT,
+				    AMT_FILTER_FWD_NEW,
+				    AMT_ACT_GMI,
+				    v6);
+	} else {
+/* Router State   Report Rec'd New Router State        Actions
+ * ------------   ------------ ----------------        -------
+ * EXCLUDE (X,Y)  TO_IN (A)    EXCLUDE (X+A,Y-A)       (A)=GMI
+ *						       Send Q(G,X-A)
+ *						       Send Q(G)
+ */
+		/* Update TO_IN (A) sources as FWD/NEW */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_UNI,
+				    AMT_FILTER_NONE_NEW,
+				    AMT_ACT_STATUS_FWD_NEW,
+				    v6);
+		/* Update EXCLUDE(X,) sources as FWD/NEW */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_UNI,
+				    AMT_FILTER_FWD,
+				    AMT_ACT_STATUS_FWD_NEW,
+				    v6);
+		/* EXCLUDE (, Y-A)
+		 * (A) are already switched to FWD_NEW.
+		 * So, D_FWD/OLD -> D_FWD/NEW is okay.
+		 */
+		amt_lookup_act_srcs(tunnel, gnode, zero_grec, AMT_OPS_UNI,
+				    AMT_FILTER_D_FWD,
+				    AMT_ACT_STATUS_D_FWD_NEW,
+				    v6);
+		/* (A)=GMI
+		 * Only FWD_NEW will have (A) sources.
+		 */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_INT,
+				    AMT_FILTER_FWD_NEW,
+				    AMT_ACT_GMI,
+				    v6);
+	}
+}
+
+static void amt_mcast_to_ex_handler(struct amt_dev *amt,
+				    struct amt_tunnel_list *tunnel,
+				    struct amt_group_node *gnode,
+				    void *grec, void *zero_grec, bool v6)
+{
+	if (gnode->filter_mode == MCAST_INCLUDE) {
+/* Router State   Report Rec'd New Router State        Actions
+ * ------------   ------------ ----------------        -------
+ * INCLUDE (A)    TO_EX (B)    EXCLUDE (A*B,B-A)       (B-A)=0
+ *						       Delete (A-B)
+ *						       Send Q(G,A*B)
+ *						       Group Timer=GMI
+ */
+		/* EXCLUDE (A*B, ) */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_INT,
+				    AMT_FILTER_FWD,
+				    AMT_ACT_STATUS_FWD_NEW,
+				    v6);
+		/* EXCLUDE (, B-A) */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_SUB_REV,
+				    AMT_FILTER_FWD,
+				    AMT_ACT_STATUS_D_FWD_NEW,
+				    v6);
+		/* (B-A)=0 */
+		amt_lookup_act_srcs(tunnel, gnode, zero_grec, AMT_OPS_UNI,
+				    AMT_FILTER_D_FWD_NEW,
+				    AMT_ACT_GMI_ZERO,
+				    v6);
+		/* Group Timer=GMI */
+		if (!mod_delayed_work(amt_wq, &gnode->group_timer,
+				      msecs_to_jiffies(amt_gmi(amt))))
+			dev_hold(amt->dev);
+		gnode->filter_mode = MCAST_EXCLUDE;
+		/* Delete (A-B) will be worked by amt_cleanup_srcs(). */
+	} else {
+/* Router State   Report Rec'd New Router State        Actions
+ * ------------   ------------ ----------------        -------
+ * EXCLUDE (X,Y)  TO_EX (A)    EXCLUDE (A-Y,Y*A)       (A-X-Y)=Group Timer
+ *						       Delete (X-A)
+ *						       Delete (Y-A)
+ *						       Send Q(G,A-Y)
+ *						       Group Timer=GMI
+ */
+		/* Update (A-X-Y) as NONE/OLD */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_SUB_REV,
+				    AMT_FILTER_BOTH,
+				    AMT_ACT_GT,
+				    v6);
+		/* EXCLUDE (A-Y, ) */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_SUB_REV,
+				    AMT_FILTER_D_FWD,
+				    AMT_ACT_STATUS_FWD_NEW,
+				    v6);
+		/* EXCLUDE (, Y*A) */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_INT,
+				    AMT_FILTER_D_FWD,
+				    AMT_ACT_STATUS_D_FWD_NEW,
+				    v6);
+		/* Group Timer=GMI */
+		if (!mod_delayed_work(amt_wq, &gnode->group_timer,
+				      msecs_to_jiffies(amt_gmi(amt))))
+			dev_hold(amt->dev);
+		/* Delete (X-A), (Y-A) will be worked by amt_cleanup_srcs(). */
+	}
+}
+
+static void amt_mcast_allow_handler(struct amt_dev *amt,
+				    struct amt_tunnel_list *tunnel,
+				    struct amt_group_node *gnode,
+				    void *grec, void *zero_grec, bool v6)
+{
+	if (gnode->filter_mode == MCAST_INCLUDE) {
+/* Router State   Report Rec'd New Router State        Actions
+ * ------------   ------------ ----------------        -------
+ * INCLUDE (A)    ALLOW (B)    INCLUDE (A+B)	       (B)=GMI
+ */
+		/* INCLUDE (A+B) */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_UNI,
+				    AMT_FILTER_FWD,
+				    AMT_ACT_STATUS_FWD_NEW,
+				    v6);
+		/* (B)=GMI */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_INT,
+				    AMT_FILTER_FWD_NEW,
+				    AMT_ACT_GMI,
+				    v6);
+	} else {
+/* Router State   Report Rec'd New Router State        Actions
+ * ------------   ------------ ----------------        -------
+ * EXCLUDE (X,Y)  ALLOW (A)    EXCLUDE (X+A,Y-A)       (A)=GMI
+ */
+		/* EXCLUDE (X+A, ) */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_UNI,
+				    AMT_FILTER_FWD,
+				    AMT_ACT_STATUS_FWD_NEW,
+				    v6);
+		/* EXCLUDE (, Y-A) */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_SUB,
+				    AMT_FILTER_D_FWD,
+				    AMT_ACT_STATUS_D_FWD_NEW,
+				    v6);
+		/* (A)=GMI
+		 * All (A) source are now FWD/NEW status.
+		 */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_INT,
+				    AMT_FILTER_FWD_NEW,
+				    AMT_ACT_GMI,
+				    v6);
+	}
+}
+
+static void amt_mcast_block_handler(struct amt_dev *amt,
+				    struct amt_tunnel_list *tunnel,
+				    struct amt_group_node *gnode,
+				    void *grec, void *zero_grec, bool v6)
+{
+	if (gnode->filter_mode == MCAST_INCLUDE) {
+/* Router State   Report Rec'd New Router State        Actions
+ * ------------   ------------ ----------------        -------
+ * INCLUDE (A)    BLOCK (B)    INCLUDE (A)             Send Q(G,A*B)
+ */
+		/* INCLUDE (A) */
+		amt_lookup_act_srcs(tunnel, gnode, zero_grec, AMT_OPS_UNI,
+				    AMT_FILTER_FWD,
+				    AMT_ACT_STATUS_FWD_NEW,
+				    v6);
+	} else {
+/* Router State   Report Rec'd New Router State        Actions
+ * ------------   ------------ ----------------        -------
+ * EXCLUDE (X,Y)  BLOCK (A)    EXCLUDE (X+(A-Y),Y)     (A-X-Y)=Group Timer
+ *						       Send Q(G,A-Y)
+ */
+		/* (A-X-Y)=Group Timer */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_SUB_REV,
+				    AMT_FILTER_BOTH,
+				    AMT_ACT_GT,
+				    v6);
+		/* EXCLUDE (X, ) */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_UNI,
+				    AMT_FILTER_FWD,
+				    AMT_ACT_STATUS_FWD_NEW,
+				    v6);
+		/* EXCLUDE (X+(A-Y) */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_SUB_REV,
+				    AMT_FILTER_D_FWD,
+				    AMT_ACT_STATUS_FWD_NEW,
+				    v6);
+		/* EXCLUDE (, Y) */
+		amt_lookup_act_srcs(tunnel, gnode, grec, AMT_OPS_UNI,
+				    AMT_FILTER_D_FWD,
+				    AMT_ACT_STATUS_D_FWD_NEW,
+				    v6);
+	}
+}
+
+/* RFC 3376
+ * 7.3.2. In the Presence of Older Version Group Members
+ *
+ * When Group Compatibility Mode is IGMPv2, a router internally
+ * translates the following IGMPv2 messages for that group to their
+ * IGMPv3 equivalents:
+ *
+ * IGMPv2 Message                IGMPv3 Equivalent
+ * --------------                -----------------
+ * Report                        IS_EX( {} )
+ * Leave                         TO_IN( {} )
+ */
+static void amt_igmpv2_report_handler(struct amt_dev *amt, struct sk_buff *skb,
+				      struct amt_tunnel_list *tunnel)
+{
+	struct igmphdr *ih = igmp_hdr(skb);
+	struct iphdr *iph = ip_hdr(skb);
+	struct amt_group_node *gnode;
+	union amt_addr group, host;
+
+	memset(&group, 0, sizeof(union amt_addr));
+	group.ip4 = ih->group;
+	memset(&host, 0, sizeof(union amt_addr));
+	host.ip4 = iph->saddr;
+
+	gnode = amt_lookup_group(tunnel, &group, &host, ETH_P_IP);
+	if (!gnode) {
+		gnode = amt_add_group(amt, tunnel, &group, &host, ETH_P_IP);
+		if (!IS_ERR(gnode)) {
+			gnode->filter_mode = MCAST_EXCLUDE;
+			if (!mod_delayed_work(amt_wq, &gnode->group_timer,
+					      msecs_to_jiffies(amt_gmi(amt))))
+				dev_hold(amt->dev);
+		}
+	}
+}
+
+/* RFC 3376
+ * 7.3.2. In the Presence of Older Version Group Members
+ *
+ * When Group Compatibility Mode is IGMPv2, a router internally
+ * translates the following IGMPv2 messages for that group to their
+ * IGMPv3 equivalents:
+ *
+ * IGMPv2 Message                IGMPv3 Equivalent
+ * --------------                -----------------
+ * Report                        IS_EX( {} )
+ * Leave                         TO_IN( {} )
+ */
+static void amt_igmpv2_leave_handler(struct amt_dev *amt, struct sk_buff *skb,
+				     struct amt_tunnel_list *tunnel)
+{
+	struct igmphdr *ih = igmp_hdr(skb);
+	struct iphdr *iph = ip_hdr(skb);
+	struct amt_group_node *gnode;
+	union amt_addr group, host;
+
+	memset(&group, 0, sizeof(union amt_addr));
+	group.ip4 = ih->group;
+	memset(&host, 0, sizeof(union amt_addr));
+	host.ip4 = iph->saddr;
+
+	gnode = amt_lookup_group(tunnel, &group, &host, ETH_P_IP);
+	if (gnode)
+		amt_del_group(amt, gnode);
+}
+
+static void amt_igmpv3_report_handler(struct amt_dev *amt, struct sk_buff *skb,
+				      struct amt_tunnel_list *tunnel)
+{
+	struct igmpv3_report *ihrv3 = igmpv3_report_hdr(skb);
+	int len = skb_transport_offset(skb) + sizeof(*ihrv3);
+	void *zero_grec = (void *)&igmpv3_zero_grec;
+	struct iphdr *iph = ip_hdr(skb);
+	struct amt_group_node *gnode;
+	union amt_addr group, host;
+	struct igmpv3_grec *grec;
+	u16 nsrcs;
+	int i;
+
+	for (i = 0; i < ntohs(ihrv3->ngrec); i++) {
+		len += sizeof(*grec);
+		if (!ip_mc_may_pull(skb, len))
+			break;
+
+		grec = (void *)(skb->data + len - sizeof(*grec));
+		nsrcs = ntohs(grec->grec_nsrcs);
+
+		len += nsrcs * sizeof(__be32);
+		if (!ip_mc_may_pull(skb, len))
+			break;
+
+		memset(&group, 0, sizeof(union amt_addr));
+		group.ip4 = grec->grec_mca;
+		memset(&host, 0, sizeof(union amt_addr));
+		host.ip4 = iph->saddr;
+		gnode = amt_lookup_group(tunnel, &group, &host, ETH_P_IP);
+		if (!gnode) {
+			gnode = amt_add_group(amt, tunnel, &group, &host,
+					      ETH_P_IP);
+			if (IS_ERR(gnode))
+				continue;
+		}
+
+		amt_add_srcs(amt, tunnel, gnode, grec, false);
+		switch (grec->grec_type) {
+		case IGMPV3_MODE_IS_INCLUDE:
+			amt_mcast_is_in_handler(amt, tunnel, gnode, grec,
+						zero_grec, false);
+			break;
+		case IGMPV3_MODE_IS_EXCLUDE:
+			amt_mcast_is_ex_handler(amt, tunnel, gnode, grec,
+						zero_grec, false);
+			break;
+		case IGMPV3_CHANGE_TO_INCLUDE:
+			amt_mcast_to_in_handler(amt, tunnel, gnode, grec,
+						zero_grec, false);
+			break;
+		case IGMPV3_CHANGE_TO_EXCLUDE:
+			amt_mcast_to_ex_handler(amt, tunnel, gnode, grec,
+						zero_grec, false);
+			break;
+		case IGMPV3_ALLOW_NEW_SOURCES:
+			amt_mcast_allow_handler(amt, tunnel, gnode, grec,
+						zero_grec, false);
+			break;
+		case IGMPV3_BLOCK_OLD_SOURCES:
+			amt_mcast_block_handler(amt, tunnel, gnode, grec,
+						zero_grec, false);
+			break;
+		default:
+			break;
+		}
+		amt_cleanup_srcs(amt, tunnel, gnode);
+	}
+}
+
+/* caller held tunnel->lock */
+static void amt_igmp_report_handler(struct amt_dev *amt, struct sk_buff *skb,
+				    struct amt_tunnel_list *tunnel)
+{
+	struct igmphdr *ih = igmp_hdr(skb);
+
+	switch (ih->type) {
+	case IGMPV3_HOST_MEMBERSHIP_REPORT:
+		amt_igmpv3_report_handler(amt, skb, tunnel);
+		break;
+	case IGMPV2_HOST_MEMBERSHIP_REPORT:
+		amt_igmpv2_report_handler(amt, skb, tunnel);
+		break;
+	case IGMP_HOST_LEAVE_MESSAGE:
+		amt_igmpv2_leave_handler(amt, skb, tunnel);
+		break;
+	default:
+		break;
+	}
+}
+
+#if IS_ENABLED(CONFIG_IPV6)
+/* RFC 3810
+ * 8.3.2. In the Presence of MLDv1 Multicast Address Listeners
+ *
+ * When Multicast Address Compatibility Mode is MLDv2, a router acts
+ * using the MLDv2 protocol for that multicast address.  When Multicast
+ * Address Compatibility Mode is MLDv1, a router internally translates
+ * the following MLDv1 messages for that multicast address to their
+ * MLDv2 equivalents:
+ *
+ * MLDv1 Message                 MLDv2 Equivalent
+ * --------------                -----------------
+ * Report                        IS_EX( {} )
+ * Done                          TO_IN( {} )
+ */
+static void amt_mldv1_report_handler(struct amt_dev *amt, struct sk_buff *skb,
+				     struct amt_tunnel_list *tunnel)
+{
+	struct mld_msg *mld = (struct mld_msg *)icmp6_hdr(skb);
+	struct ipv6hdr *ip6h = ipv6_hdr(skb);
+	struct amt_group_node *gnode;
+	union amt_addr group, host;
+
+	memcpy(&group.ip6, &mld->mld_mca, sizeof(struct in6_addr));
+	memcpy(&host.ip6, &ip6h->saddr, sizeof(struct in6_addr));
+
+	gnode = amt_lookup_group(tunnel, &group, &host, ETH_P_IPV6);
+	if (!gnode) {
+		gnode = amt_add_group(amt, tunnel, &group, &host, ETH_P_IPV6);
+		if (!IS_ERR(gnode)) {
+			gnode->filter_mode = MCAST_EXCLUDE;
+			if (!mod_delayed_work(amt_wq, &gnode->group_timer,
+					      msecs_to_jiffies(amt_gmi(amt))))
+				dev_hold(amt->dev);
+		}
+	}
+}
+
+/* RFC 3810
+ * 8.3.2. In the Presence of MLDv1 Multicast Address Listeners
+ *
+ * When Multicast Address Compatibility Mode is MLDv2, a router acts
+ * using the MLDv2 protocol for that multicast address.  When Multicast
+ * Address Compatibility Mode is MLDv1, a router internally translates
+ * the following MLDv1 messages for that multicast address to their
+ * MLDv2 equivalents:
+ *
+ * MLDv1 Message                 MLDv2 Equivalent
+ * --------------                -----------------
+ * Report                        IS_EX( {} )
+ * Done                          TO_IN( {} )
+ */
+static void amt_mldv1_leave_handler(struct amt_dev *amt, struct sk_buff *skb,
+				    struct amt_tunnel_list *tunnel)
+{
+	struct mld_msg *mld = (struct mld_msg *)icmp6_hdr(skb);
+	struct iphdr *iph = ip_hdr(skb);
+	struct amt_group_node *gnode;
+	union amt_addr group, host;
+
+	memcpy(&group.ip6, &mld->mld_mca, sizeof(struct in6_addr));
+	memset(&host, 0, sizeof(union amt_addr));
+	host.ip4 = iph->saddr;
+
+	gnode = amt_lookup_group(tunnel, &group, &host, ETH_P_IPV6);
+	if (gnode) {
+		amt_del_group(amt, gnode);
+		return;
+	}
+}
+
+static void amt_mldv2_report_handler(struct amt_dev *amt, struct sk_buff *skb,
+				     struct amt_tunnel_list *tunnel)
+{
+	struct mld2_report *mld2r = (struct mld2_report *)icmp6_hdr(skb);
+	int len = skb_transport_offset(skb) + sizeof(*mld2r);
+	void *zero_grec = (void *)&mldv2_zero_grec;
+	struct ipv6hdr *ip6h = ipv6_hdr(skb);
+	struct amt_group_node *gnode;
+	union amt_addr group, host;
+	struct mld2_grec *grec;
+	u16 nsrcs;
+	int i;
+
+	for (i = 0; i < ntohs(mld2r->mld2r_ngrec); i++) {
+		len += sizeof(*grec);
+		if (!ipv6_mc_may_pull(skb, len))
+			break;
+
+		grec = (void *)(skb->data + len - sizeof(*grec));
+		nsrcs = ntohs(grec->grec_nsrcs);
+
+		len += nsrcs * sizeof(struct in6_addr);
+		if (!ipv6_mc_may_pull(skb, len))
+			break;
+
+		memset(&group, 0, sizeof(union amt_addr));
+		group.ip6 = grec->grec_mca;
+		memset(&host, 0, sizeof(union amt_addr));
+		host.ip6 = ip6h->saddr;
+		gnode = amt_lookup_group(tunnel, &group, &host, ETH_P_IPV6);
+		if (!gnode) {
+			gnode = amt_add_group(amt, tunnel, &group, &host,
+					      ETH_P_IPV6);
+			if (IS_ERR(gnode))
+				continue;
+		}
+
+		amt_add_srcs(amt, tunnel, gnode, grec, true);
+		switch (grec->grec_type) {
+		case MLD2_MODE_IS_INCLUDE:
+			amt_mcast_is_in_handler(amt, tunnel, gnode, grec,
+						zero_grec, true);
+			break;
+		case MLD2_MODE_IS_EXCLUDE:
+			amt_mcast_is_ex_handler(amt, tunnel, gnode, grec,
+						zero_grec, true);
+			break;
+		case MLD2_CHANGE_TO_INCLUDE:
+			amt_mcast_to_in_handler(amt, tunnel, gnode, grec,
+						zero_grec, true);
+			break;
+		case MLD2_CHANGE_TO_EXCLUDE:
+			amt_mcast_to_ex_handler(amt, tunnel, gnode, grec,
+						zero_grec, true);
+			break;
+		case MLD2_ALLOW_NEW_SOURCES:
+			amt_mcast_allow_handler(amt, tunnel, gnode, grec,
+						zero_grec, true);
+			break;
+		case MLD2_BLOCK_OLD_SOURCES:
+			amt_mcast_block_handler(amt, tunnel, gnode, grec,
+						zero_grec, true);
+			break;
+		default:
+			break;
+		}
+		amt_cleanup_srcs(amt, tunnel, gnode);
+	}
+}
+
+/* caller held tunnel->lock */
+static void amt_mld_report_handler(struct amt_dev *amt, struct sk_buff *skb,
+				   struct amt_tunnel_list *tunnel)
+{
+	struct mld_msg *mld = (struct mld_msg *)icmp6_hdr(skb);
+
+	switch (mld->mld_type) {
+	case ICMPV6_MGM_REPORT:
+		amt_mldv1_report_handler(amt, skb, tunnel);
+		break;
+	case ICMPV6_MLD2_REPORT:
+		amt_mldv2_report_handler(amt, skb, tunnel);
+		break;
+	case ICMPV6_MGM_REDUCTION:
+		amt_mldv1_leave_handler(amt, skb, tunnel);
+		break;
+	default:
+		break;
+	}
+}
+#endif
+
+static bool amt_advertisement_handler(struct amt_dev *amt, struct sk_buff *skb)
+{
+	struct amt_header_advertisement *amta;
+	int hdr_size;
+
+	hdr_size = sizeof(*amta) - sizeof(struct amt_header);
+
+	if (!pskb_may_pull(skb, hdr_size))
+		return true;
+
+	amta = (struct amt_header_advertisement *)(udp_hdr(skb) + 1);
+	if (!amta->ip4)
+		return true;
+
+	if (amta->reserved || amta->version)
+		return true;
+
+	if (ipv4_is_loopback(amta->ip4) || ipv4_is_multicast(amta->ip4))
+		return true;
+
+	amt->remote_ip = amta->ip4;
+	netdev_dbg(amt->dev, "advertised remote ip = %pI4\n", &amt->remote_ip);
+	mod_delayed_work(amt_wq, &amt->req_wq, 0);
+
+	amt_update_gw_status(amt, AMT_STATUS_RECEIVED_ADVERTISEMENT, true);
+	return false;
+}
+
+static bool amt_multicast_data_handler(struct amt_dev *amt, struct sk_buff *skb)
+{
+	struct amt_header_mcast_data *amtmd;
+	int hdr_size, len, err;
+	struct ethhdr *eth;
+	struct iphdr *iph;
+
+	amtmd = (struct amt_header_mcast_data *)(udp_hdr(skb) + 1);
+	if (amtmd->reserved || amtmd->version)
+		return true;
+
+	hdr_size = sizeof(*amtmd) + sizeof(struct udphdr);
+	if (iptunnel_pull_header(skb, hdr_size, htons(ETH_P_IP), false))
+		return true;
+	skb_reset_network_header(skb);
+	skb_push(skb, sizeof(*eth));
+	skb_reset_mac_header(skb);
+	skb_pull(skb, sizeof(*eth));
+	eth = eth_hdr(skb);
+	iph = ip_hdr(skb);
+	if (iph->version == 4) {
+		if (!ipv4_is_multicast(iph->daddr))
+			return true;
+		skb->protocol = htons(ETH_P_IP);
+		eth->h_proto = htons(ETH_P_IP);
+		ip_eth_mc_map(iph->daddr, eth->h_dest);
+#if IS_ENABLED(CONFIG_IPV6)
+	} else if (iph->version == 6) {
+		struct ipv6hdr *ip6h;
+
+		ip6h = ipv6_hdr(skb);
+		if (!ipv6_addr_is_multicast(&ip6h->daddr))
+			return true;
+		skb->protocol = htons(ETH_P_IPV6);
+		eth->h_proto = htons(ETH_P_IPV6);
+		ipv6_eth_mc_map(&ip6h->daddr, eth->h_dest);
+#endif
+	} else {
+		return true;
+	}
+
+	skb->pkt_type = PACKET_MULTICAST;
+	skb->ip_summed = CHECKSUM_UNNECESSARY;
+	len = skb->len;
+	err = gro_cells_receive(&amt->gro_cells, skb);
+	if (likely(err == NET_RX_SUCCESS))
+		dev_sw_netstats_rx_add(amt->dev, len);
+	else
+		amt->dev->stats.rx_dropped++;
+
+	return false;
+}
+
+static bool amt_membership_query_handler(struct amt_dev *amt,
+					 struct sk_buff *skb)
+{
+	struct amt_header_membership_query *amtmq;
+	struct igmpv3_query *ihv3;
+	struct ethhdr *eth, *oeth;
+	struct iphdr *iph;
+	int hdr_size, len;
+
+	hdr_size = sizeof(*amtmq) - sizeof(struct amt_header);
+
+	if (!pskb_may_pull(skb, hdr_size))
+		return true;
+
+	amtmq = (struct amt_header_membership_query *)(udp_hdr(skb) + 1);
+	if (amtmq->reserved || amtmq->version)
+		return true;
+
+	hdr_size = sizeof(*amtmq) + sizeof(struct udphdr) - sizeof(*eth);
+	if (iptunnel_pull_header(skb, hdr_size, htons(ETH_P_TEB), false))
+		return true;
+	oeth = eth_hdr(skb);
+	skb_reset_mac_header(skb);
+	skb_pull(skb, sizeof(*eth));
+	skb_reset_network_header(skb);
+	eth = eth_hdr(skb);
+	iph = ip_hdr(skb);
+	if (iph->version == 4) {
+		if (!ipv4_is_multicast(iph->daddr))
+			return true;
+		if (!pskb_may_pull(skb, sizeof(*iph) +  4 + sizeof(*ihv3)))
+			return true;
+
+		ihv3 = skb_pull(skb, sizeof(*iph) + 4);
+		skb_reset_transport_header(skb);
+		skb_push(skb, sizeof(*iph) + 4);
+		spin_lock_bh(&amt->lock);
+		amt->ready4 = true;
+		amt->mac = amtmq->response_mac;
+		amt->req_cnt = 0;
+		amt->qi = ihv3->qqic;
+		spin_unlock_bh(&amt->lock);
+		skb->protocol = htons(ETH_P_IP);
+		eth->h_proto = htons(ETH_P_IP);
+		ip_eth_mc_map(iph->daddr, eth->h_dest);
+#if IS_ENABLED(CONFIG_IPV6)
+	} else if (iph->version == 6) {
+		struct ipv6hdr *ip6h = ipv6_hdr(skb);
+		struct mld2_query *mld2q;
+
+		if (!ipv6_addr_is_multicast(&ip6h->daddr))
+			return true;
+		if (!pskb_may_pull(skb, sizeof(*ip6h) + 8 + sizeof(*mld2q)))
+			return true;
+
+		mld2q = skb_pull(skb, sizeof(*ip6h) + 8);
+		skb_reset_transport_header(skb);
+		skb_push(skb, sizeof(*ip6h) + 8);
+		spin_lock_bh(&amt->lock);
+		amt->ready6 = true;
+		amt->mac = amtmq->response_mac;
+		amt->req_cnt = 0;
+		amt->qi = mld2q->mld2q_qqic;
+		spin_unlock_bh(&amt->lock);
+		skb->protocol = htons(ETH_P_IPV6);
+		eth->h_proto = htons(ETH_P_IPV6);
+		ipv6_eth_mc_map(&ip6h->daddr, eth->h_dest);
+#endif
+	} else {
+		return true;
+	}
+
+	ether_addr_copy(eth->h_source, oeth->h_source);
+	skb->pkt_type = PACKET_MULTICAST;
+	skb->ip_summed = CHECKSUM_UNNECESSARY;
+	len = skb->len;
+	if (netif_rx(skb) == NET_RX_SUCCESS) {
+		amt_update_gw_status(amt, AMT_STATUS_RECEIVED_QUERY, true);
+		dev_sw_netstats_rx_add(amt->dev, len);
+	} else {
+		amt->dev->stats.rx_dropped++;
+	}
+
+	return false;
+}
+
+static bool amt_update_handler(struct amt_dev *amt, struct sk_buff *skb)
+{
+	struct amt_header_membership_update *amtmu;
+	struct amt_tunnel_list *tunnel;
+	struct udphdr *udph;
+	struct ethhdr *eth;
+	struct iphdr *iph;
+	int len;
+
+	iph = ip_hdr(skb);
+	udph = udp_hdr(skb);
+
+	if (__iptunnel_pull_header(skb, sizeof(*udph), skb->protocol,
+				   false, false))
+		return true;
+
+	if (skb->protocol != ntohs(ETH_P_IP))
+		return true;
+
+	amtmu = (struct amt_header_membership_update *)skb->data;
+	if (amtmu->reserved || amtmu->version)
+		return true;
+
+	skb_pull(skb, sizeof(*amtmu));
+	skb_reset_network_header(skb);
+
+	list_for_each_entry_rcu(tunnel, &amt->tunnel_list, list) {
+		if (tunnel->ip4 == iph->saddr) {
+			if ((amtmu->nonce == tunnel->nonce &&
+			     amtmu->response_mac == tunnel->mac)) {
+				mod_delayed_work(amt_wq, &tunnel->gc_wq,
+						 msecs_to_jiffies(amt_gmi(amt)) * 3);
+				goto report;
+			} else {
+				netdev_dbg(amt->dev, "Invalid MAC\n");
+				return true;
+			}
+		}
+	}
+
+	return false;
+
+report:
+	iph = ip_hdr(skb);
+	if (iph->version == 4) {
+		if (ip_mc_check_igmp(skb)) {
+			netdev_dbg(amt->dev, "Invalid IGMP\n");
+			return true;
+		}
+
+		spin_lock_bh(&tunnel->lock);
+		amt_igmp_report_handler(amt, skb, tunnel);
+		spin_unlock_bh(&tunnel->lock);
+
+		skb_push(skb, sizeof(struct ethhdr));
+		skb_reset_mac_header(skb);
+		eth = eth_hdr(skb);
+		skb->protocol = htons(ETH_P_IP);
+		eth->h_proto = htons(ETH_P_IP);
+		ip_eth_mc_map(iph->daddr, eth->h_dest);
+#if IS_ENABLED(CONFIG_IPV6)
+	} else if (iph->version == 6) {
+		struct ipv6hdr *ip6h = ipv6_hdr(skb);
+
+		if (ipv6_mc_check_mld(skb)) {
+			netdev_dbg(amt->dev, "Invalid MLD\n");
+			return true;
+		}
+
+		spin_lock_bh(&tunnel->lock);
+		amt_mld_report_handler(amt, skb, tunnel);
+		spin_unlock_bh(&tunnel->lock);
+
+		skb_push(skb, sizeof(struct ethhdr));
+		skb_reset_mac_header(skb);
+		eth = eth_hdr(skb);
+		skb->protocol = htons(ETH_P_IPV6);
+		eth->h_proto = htons(ETH_P_IPV6);
+		ipv6_eth_mc_map(&ip6h->daddr, eth->h_dest);
+#endif
+	} else {
+		netdev_dbg(amt->dev, "Unsupported Protocol\n");
+		return true;
+	}
+
+	skb_pull(skb, sizeof(struct ethhdr));
+	skb->pkt_type = PACKET_MULTICAST;
+	skb->ip_summed = CHECKSUM_UNNECESSARY;
+	len = skb->len;
+	if (netif_rx(skb) == NET_RX_SUCCESS) {
+		amt_update_relay_status(tunnel, AMT_STATUS_RECEIVED_UPDATE, true);
+		dev_sw_netstats_rx_add(amt->dev, len);
+	} else {
+		amt->dev->stats.rx_dropped++;
+	}
+
+	return false;
+}
+
+static void amt_send_advertisement(struct amt_dev *amt, __be32 nonce,
+				   __be32 daddr, __be16 dport)
+{
+	struct amt_header_advertisement *amta;
+	int hlen, tlen, offset;
+	struct socket *sock;
+	struct udphdr *udph;
+	struct sk_buff *skb;
+	struct iphdr *iph;
+	struct rtable *rt;
+	struct flowi4 fl4;
+	u32 len;
+	int err;
+
+	rcu_read_lock();
+	sock = rcu_dereference(amt->sock);
+	if (!sock)
+		goto out;
+
+	if (!netif_running(amt->stream_dev) || !netif_running(amt->dev))
+		goto out;
+
+	rt = ip_route_output_ports(amt->net, &fl4, sock->sk,
+				   daddr, amt->local_ip,
+				   dport, amt->relay_port,
+				   IPPROTO_UDP, 0,
+				   amt->stream_dev->ifindex);
+	if (IS_ERR(rt)) {
+		amt->dev->stats.tx_errors++;
+		goto out;
+	}
+
+	hlen = LL_RESERVED_SPACE(amt->dev);
+	tlen = amt->dev->needed_tailroom;
+	len = hlen + tlen + sizeof(*iph) + sizeof(*udph) + sizeof(*amta);
+	skb = netdev_alloc_skb_ip_align(amt->dev, len);
+	if (!skb) {
+		ip_rt_put(rt);
+		amt->dev->stats.tx_errors++;
+		goto out;
+	}
+
+	skb->priority = TC_PRIO_CONTROL;
+	skb_dst_set(skb, &rt->dst);
+
+	len = sizeof(*iph) + sizeof(*udph) + sizeof(*amta);
+	skb_reset_network_header(skb);
+	skb_put(skb, len);
+	amta = skb_pull(skb, sizeof(*iph) + sizeof(*udph));
+	amta->version	= 0;
+	amta->type	= AMT_MSG_ADVERTISEMENT;
+	amta->reserved	= 0;
+	amta->nonce	= nonce;
+	amta->ip4	= amt->local_ip;
+	skb_push(skb, sizeof(*udph));
+	skb_reset_transport_header(skb);
+	udph		= udp_hdr(skb);
+	udph->source	= amt->relay_port;
+	udph->dest	= dport;
+	udph->len	= htons(sizeof(*amta) + sizeof(*udph));
+	udph->check	= 0;
+	offset = skb_transport_offset(skb);
+	skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
+	udph->check = csum_tcpudp_magic(amt->local_ip, daddr,
+					sizeof(*udph) + sizeof(*amta),
+					IPPROTO_UDP, skb->csum);
+
+	skb_push(skb, sizeof(*iph));
+	iph		= ip_hdr(skb);
+	iph->version	= 4;
+	iph->ihl	= (sizeof(struct iphdr)) >> 2;
+	iph->tos	= 0xc0;
+	iph->frag_off	= 0;
+	iph->ttl	= ip4_dst_hoplimit(&rt->dst);
+	iph->daddr	= daddr;
+	iph->saddr	= amt->local_ip;
+	iph->protocol	= IPPROTO_UDP;
+	iph->tot_len	= htons(len);
+
+	skb->ip_summed = CHECKSUM_NONE;
+	ip_select_ident(amt->net, skb, NULL);
+	ip_send_check(iph);
+	err = ip_local_out(amt->net, sock->sk, skb);
+	if (unlikely(net_xmit_eval(err)))
+		amt->dev->stats.tx_errors++;
+
+out:
+	rcu_read_unlock();
+}
+
+static bool amt_discovery_handler(struct amt_dev *amt, struct sk_buff *skb)
+{
+	struct amt_header_discovery *amtd;
+	struct udphdr *udph;
+	struct iphdr *iph;
+	__be32 nonce;
+
+	if (!pskb_may_pull(skb, sizeof(*udph) + sizeof(*amtd)))
+		return true;
+
+	iph = ip_hdr(skb);
+	udph = udp_hdr(skb);
+	amtd = (struct amt_header_discovery *)(udp_hdr(skb) + 1);
+
+	if (amtd->reserved || amtd->version)
+		return true;
+
+	nonce = amtd->nonce;
+
+	amt_send_advertisement(amt, nonce, iph->saddr, udph->source);
+
+	return false;
+}
+
+static bool amt_request_handler(struct amt_dev *amt, struct sk_buff *skb)
+{
+	struct amt_header_request *amtrh;
+	struct amt_tunnel_list *tunnel;
+	unsigned long long key;
+	struct udphdr *udph;
+	struct iphdr *iph;
+	u64 mac;
+	int i;
+
+	if (!pskb_may_pull(skb, sizeof(*udph) + sizeof(*amtrh)))
+		return true;
+
+	iph = ip_hdr(skb);
+	udph = udp_hdr(skb);
+	amtrh = (struct amt_header_request *)(udp_hdr(skb) + 1);
+
+	if (amtrh->reserved1 || amtrh->reserved2 || amtrh->version)
+		return true;
+
+	list_for_each_entry_rcu(tunnel, &amt->tunnel_list, list)
+		if (tunnel->ip4 == iph->saddr)
+			goto send;
+
+	if (amt->nr_tunnels >= amt->max_tunnels) {
+		icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
+		return true;
+	}
+
+	tunnel = kmalloc(sizeof(*tunnel) +
+			 (sizeof(struct hlist_head) * amt->hash_buckets),
+			 GFP_ATOMIC);
+	if (!tunnel)
+		return true;
+
+	tunnel->source_port = udph->source;
+	tunnel->ip4 = iph->saddr;
+	tunnel->nr_groups = 0;
+	tunnel->nr_sources = 0;
+
+	memcpy(&key, &tunnel->key, sizeof(unsigned long long));
+	tunnel->reserved = 0;
+	tunnel->amt = amt;
+	spin_lock_init(&tunnel->lock);
+	for (i = 0; i < amt->hash_buckets; i++)
+		INIT_HLIST_HEAD(&tunnel->groups[i]);
+
+	INIT_DELAYED_WORK(&tunnel->gc_wq, amt_tunnel_expire);
+
+	spin_lock_bh(&amt->lock);
+	list_add_tail_rcu(&tunnel->list, &amt->tunnel_list);
+	tunnel->key = amt->key;
+	amt_update_relay_status(tunnel, AMT_STATUS_RECEIVED_REQUEST, true);
+	amt->nr_tunnels++;
+	mod_delayed_work(amt_wq, &tunnel->gc_wq,
+			 msecs_to_jiffies(amt_gmi(amt)));
+	spin_unlock_bh(&amt->lock);
+
+send:
+	tunnel->nonce = amtrh->nonce;
+	mac = siphash_3u32(tunnel->ip4, tunnel->source_port, tunnel->nonce,
+			   &tunnel->key);
+	tunnel->mac = mac >> 16;
+
+	if (!netif_running(amt->dev) || !netif_running(amt->stream_dev))
+		return true;
+
+	if (!amtrh->p)
+		amt_send_igmp_gq(amt, tunnel);
+	else
+		amt_send_mld_gq(amt, tunnel);
+
+	return false;
+}
+
+static int amt_rcv(struct sock *sk, struct sk_buff *skb)
+{
+	struct amt_dev *amt;
+	struct iphdr *iph;
+	int type;
+	bool err;
+
+	rcu_read_lock_bh();
+	amt = rcu_dereference_sk_user_data(sk);
+	if (!amt) {
+		err = true;
+		goto out;
+	}
+
+	skb->dev = amt->dev;
+	iph = ip_hdr(skb);
+	type = amt_parse_type(skb);
+	if (type == -1) {
+		err = true;
+		goto drop;
+	}
+
+	if (amt->mode == AMT_MODE_GATEWAY) {
+		switch (type) {
+		case AMT_MSG_ADVERTISEMENT:
+			if (iph->saddr != amt->discovery_ip) {
+				netdev_dbg(amt->dev, "Invalid Relay IP\n");
+				err = true;
+				goto drop;
+			}
+			if (amt_advertisement_handler(amt, skb))
+				amt->dev->stats.rx_dropped++;
+			goto out;
+		case AMT_MSG_MULTICAST_DATA:
+			if (iph->saddr != amt->remote_ip) {
+				netdev_dbg(amt->dev, "Invalid Relay IP\n");
+				err = true;
+				goto drop;
+			}
+			err = amt_multicast_data_handler(amt, skb);
+			if (err)
+				goto drop;
+			else
+				goto out;
+		case AMT_MSG_MEMBERSHIP_QUERY:
+			if (iph->saddr != amt->remote_ip) {
+				netdev_dbg(amt->dev, "Invalid Relay IP\n");
+				err = true;
+				goto drop;
+			}
+			err = amt_membership_query_handler(amt, skb);
+			if (err)
+				goto drop;
+			else
+				goto out;
+		default:
+			err = true;
+			netdev_dbg(amt->dev, "Invalid type of Gateway\n");
+			break;
+		}
+	} else {
+		switch (type) {
+		case AMT_MSG_DISCOVERY:
+			err = amt_discovery_handler(amt, skb);
+			break;
+		case AMT_MSG_REQUEST:
+			err = amt_request_handler(amt, skb);
+			break;
+		case AMT_MSG_MEMBERSHIP_UPDATE:
+			err = amt_update_handler(amt, skb);
+			if (err)
+				goto drop;
+			else
+				goto out;
+		default:
+			err = true;
+			netdev_dbg(amt->dev, "Invalid type of relay\n");
+			break;
+		}
+	}
+drop:
+	if (err) {
+		amt->dev->stats.rx_dropped++;
+		kfree_skb(skb);
+	} else {
+		consume_skb(skb);
+	}
+out:
+	rcu_read_unlock_bh();
+	return 0;
+}
+
+static int amt_err_lookup(struct sock *sk, struct sk_buff *skb)
+{
+	struct amt_dev *amt;
+	int type;
+
+	rcu_read_lock_bh();
+	amt = rcu_dereference_sk_user_data(sk);
+	if (!amt)
+		goto drop;
+
+	if (amt->mode != AMT_MODE_GATEWAY)
+		goto drop;
+
+	type = amt_parse_type(skb);
+	if (type == -1)
+		goto drop;
+
+	netdev_dbg(amt->dev, "Received IGMP Unreachable of %s\n",
+		   type_str[type]);
+	switch (type) {
+	case AMT_MSG_DISCOVERY:
+		break;
+	case AMT_MSG_REQUEST:
+	case AMT_MSG_MEMBERSHIP_UPDATE:
+		if (amt->status >= AMT_STATUS_RECEIVED_ADVERTISEMENT)
+			mod_delayed_work(amt_wq, &amt->req_wq, 0);
+		break;
+	default:
+		goto drop;
+	}
+	rcu_read_unlock_bh();
+	return 0;
+drop:
+	rcu_read_unlock_bh();
+	amt->dev->stats.rx_dropped++;
+	return 0;
+}
+
+static int amt_socket_create(struct amt_dev *amt)
+{
+	struct udp_tunnel_sock_cfg tunnel_cfg;
+	struct socket *sock;
+
+	sock = amt_create_sock(amt->net, amt->relay_port);
+	if (IS_ERR(sock))
+		return PTR_ERR(sock);
+
+	/* Mark socket as an encapsulation socket */
+	memset(&tunnel_cfg, 0, sizeof(tunnel_cfg));
+	tunnel_cfg.sk_user_data = amt;
+	tunnel_cfg.encap_type = 1;
+	tunnel_cfg.encap_rcv = amt_rcv;
+	tunnel_cfg.encap_err_lookup = amt_err_lookup;
+	tunnel_cfg.encap_destroy = NULL;
+	setup_udp_tunnel_sock(amt->net, sock, &tunnel_cfg);
+
+	rcu_assign_pointer(amt->sock, sock);
+	return 0;
+}
+
+static int amt_dev_open(struct net_device *dev)
+{
+	struct amt_dev *amt = netdev_priv(dev);
+	int err;
+
+	amt->ready4 = false;
+	amt->ready6 = false;
+
+	err = amt_socket_create(amt);
+	if (err)
+		return err;
+
+	spin_lock_bh(&amt->lock);
+	amt->req_cnt = 0;
+	get_random_bytes(&amt->key, sizeof(siphash_key_t));
+	spin_unlock_bh(&amt->lock);
+
+	amt->status = AMT_STATUS_INIT;
+	if (amt->mode == AMT_MODE_GATEWAY) {
+		mod_delayed_work(amt_wq, &amt->discovery_wq, 0);
+		mod_delayed_work(amt_wq, &amt->req_wq, 0);
+	} else if (amt->mode == AMT_MODE_RELAY) {
+		mod_delayed_work(amt_wq, &amt->secret_wq,
+				 msecs_to_jiffies(AMT_SECRET_TIMEOUT));
+	}
+	return err;
+}
+
+static int amt_dev_stop(struct net_device *dev)
+{
+	struct amt_dev *amt = netdev_priv(dev);
+	struct amt_tunnel_list *tunnel, *tmp;
+	struct socket *sock;
+
+	cancel_delayed_work_sync(&amt->req_wq);
+	cancel_delayed_work_sync(&amt->discovery_wq);
+	cancel_delayed_work_sync(&amt->secret_wq);
+
+	/* shutdown */
+	sock = rtnl_dereference(amt->sock);
+	RCU_INIT_POINTER(amt->sock, NULL);
+	synchronize_net();
+	if (sock)
+		udp_tunnel_sock_release(sock);
+
+	amt->ready4 = false;
+	amt->ready6 = false;
+
+	list_for_each_entry_safe(tunnel, tmp, &amt->tunnel_list, list) {
+		list_del_rcu(&tunnel->list);
+		amt->nr_tunnels--;
+		cancel_delayed_work_sync(&tunnel->gc_wq);
+		amt_clear_groups(tunnel);
+		kfree_rcu(tunnel, rcu);
+	}
+
+	return 0;
+}
+
+static const struct device_type amt_type = {
+	.name = "amt",
+};
+
+static int amt_dev_init(struct net_device *dev)
+{
+	struct amt_dev *amt = netdev_priv(dev);
+	int err;
+
+	amt->dev = dev;
+	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
+	if (!dev->tstats)
+		return -ENOMEM;
+
+	err = gro_cells_init(&amt->gro_cells, dev);
+	if (err) {
+		free_percpu(dev->tstats);
+		return err;
+	}
+
+	return 0;
+}
+
+static void amt_dev_uninit(struct net_device *dev)
+{
+	struct amt_dev *amt = netdev_priv(dev);
+
+	gro_cells_destroy(&amt->gro_cells);
+	free_percpu(dev->tstats);
+}
+
+static int amt_change_mtu(struct net_device *dev, int new_mtu)
+{
+	if (new_mtu > dev->max_mtu)
+		new_mtu = dev->max_mtu;
+	else if (new_mtu < dev->min_mtu)
+		new_mtu = dev->min_mtu;
+
+	dev->mtu = new_mtu;
+	return 0;
+}
+
+static const struct net_device_ops amt_netdev_ops = {
+	.ndo_init               = amt_dev_init,
+	.ndo_uninit             = amt_dev_uninit,
+	.ndo_open		= amt_dev_open,
+	.ndo_stop		= amt_dev_stop,
+	.ndo_start_xmit         = amt_dev_xmit,
+	.ndo_get_stats64        = dev_get_tstats64,
+	.ndo_change_mtu         = amt_change_mtu,
+};
+
+static void amt_link_setup(struct net_device *dev)
+{
+	dev->netdev_ops         = &amt_netdev_ops;
+	dev->needs_free_netdev  = true;
+	SET_NETDEV_DEVTYPE(dev, &amt_type);
+	dev->min_mtu		= ETH_MIN_MTU;
+	dev->max_mtu		= ETH_MAX_MTU;
+	dev->type		= ARPHRD_NONE;
+	dev->flags		= IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
+	dev->hard_header_len	= 0;
+	dev->addr_len		= 0;
+	dev->priv_flags		|= IFF_NO_QUEUE;
+	dev->features		|= NETIF_F_LLTX;
+	dev->features		|= NETIF_F_GSO_SOFTWARE;
+	dev->features		|= NETIF_F_NETNS_LOCAL;
+	dev->hw_features	|= NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_FRAGLIST;
+	dev->hw_features	|= NETIF_F_RXCSUM;
+	dev->hw_features	|= NETIF_F_GSO_SOFTWARE;
+	eth_hw_addr_random(dev);
+	eth_zero_addr(dev->broadcast);
+	ether_setup(dev);
+}
+
+static const struct nla_policy amt_policy[IFLA_AMT_MAX + 1] = {
+	[IFLA_AMT_MODE]		= { .type = NLA_U32 },
+	[IFLA_AMT_RELAY_PORT]	= { .type = NLA_U16 },
+	[IFLA_AMT_GATEWAY_PORT]	= { .type = NLA_U16 },
+	[IFLA_AMT_LINK]		= { .type = NLA_U32 },
+	[IFLA_AMT_LOCAL_IP]	= { .len = sizeof_field(struct iphdr, daddr) },
+	[IFLA_AMT_REMOTE_IP]	= { .len = sizeof_field(struct iphdr, daddr) },
+	[IFLA_AMT_DISCOVERY_IP]	= { .len = sizeof_field(struct iphdr, daddr) },
+	[IFLA_AMT_MAX_TUNNELS]	= { .type = NLA_U32 },
+};
+
+static int amt_validate(struct nlattr *tb[], struct nlattr *data[],
+			struct netlink_ext_ack *extack)
+{
+	if (!data)
+		return -EINVAL;
+
+	if (!data[IFLA_AMT_LINK]) {
+		NL_SET_ERR_MSG_ATTR(extack, data[IFLA_AMT_LINK],
+				    "link interface should not be empty");
+		return -EINVAL;
+	}
+
+	if (!data[IFLA_AMT_MODE] ||
+	    nla_get_u32(data[IFLA_AMT_MODE]) > AMT_MODE_MAX) {
+		NL_SET_ERR_MSG_ATTR(extack, data[IFLA_AMT_MODE],
+				    "mode should not be empty");
+		return -EINVAL;
+	}
+
+	if (!data[IFLA_AMT_LOCAL_IP]) {
+		NL_SET_ERR_MSG_ATTR(extack, data[IFLA_AMT_DISCOVERY_IP],
+				    "local should not be empty");
+		return -EINVAL;
+	}
+
+	if (!data[IFLA_AMT_DISCOVERY_IP] &&
+	    nla_get_u32(data[IFLA_AMT_MODE]) == AMT_MODE_GATEWAY) {
+		NL_SET_ERR_MSG_ATTR(extack, data[IFLA_AMT_LOCAL_IP],
+				    "discovery should not be empty");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int amt_newlink(struct net *net, struct net_device *dev,
+		       struct nlattr *tb[], struct nlattr *data[],
+		       struct netlink_ext_ack *extack)
+{
+	struct amt_dev *amt = netdev_priv(dev);
+	int err;
+
+	amt->net = net;
+	amt->mode = nla_get_u32(data[IFLA_AMT_MODE]);
+
+	if (data[IFLA_AMT_MAX_TUNNELS])
+		amt->max_tunnels = nla_get_u32(data[IFLA_AMT_MAX_TUNNELS]);
+	else
+		amt->max_tunnels = AMT_MAX_TUNNELS;
+
+	spin_lock_init(&amt->lock);
+	amt->max_groups = AMT_MAX_GROUP;
+	amt->max_sources = AMT_MAX_SOURCE;
+	amt->hash_buckets = AMT_HSIZE;
+	amt->nr_tunnels = 0;
+	get_random_bytes(&amt->hash_seed, sizeof(amt->hash_seed));
+	amt->stream_dev = dev_get_by_index(net, nla_get_u32(data[IFLA_AMT_LINK]));
+	if (!amt->stream_dev) {
+		NL_SET_ERR_MSG_ATTR(extack, tb[IFLA_AMT_LINK],
+				    "Can't find stream device");
+		return -ENODEV;
+	}
+
+	if (amt->stream_dev->type != ARPHRD_ETHER) {
+		NL_SET_ERR_MSG_ATTR(extack, tb[IFLA_AMT_LINK],
+				    "Invalid stream device type");
+		dev_put(amt->stream_dev);
+		return -EINVAL;
+	}
+
+	amt->local_ip = nla_get_in_addr(data[IFLA_AMT_LOCAL_IP]);
+	if (data[IFLA_AMT_RELAY_PORT])
+		amt->relay_port = nla_get_be16(data[IFLA_AMT_RELAY_PORT]);
+	else
+		amt->relay_port = htons(IANA_AMT_UDP_PORT);
+
+	if (data[IFLA_AMT_GATEWAY_PORT])
+		amt->gw_port = nla_get_be16(data[IFLA_AMT_GATEWAY_PORT]);
+	else
+		amt->gw_port = htons(IANA_AMT_UDP_PORT);
+
+	if (!amt->relay_port) {
+		NL_SET_ERR_MSG_ATTR(extack, tb[IFLA_AMT_DISCOVERY_IP],
+				    "relay port must not be 0");
+		return -EINVAL;
+	}
+	if (amt->mode == AMT_MODE_RELAY) {
+		amt->qrv = amt->net->ipv4.sysctl_igmp_qrv;
+		amt->qri = 10;
+		dev->needed_headroom = amt->stream_dev->needed_headroom +
+				       AMT_RELAY_HLEN;
+		dev->mtu = amt->stream_dev->mtu - AMT_RELAY_HLEN;
+		dev->max_mtu = dev->mtu;
+		dev->min_mtu = ETH_MIN_MTU + AMT_RELAY_HLEN;
+	} else {
+		if (!data[IFLA_AMT_DISCOVERY_IP]) {
+			NL_SET_ERR_MSG_ATTR(extack, tb[IFLA_AMT_DISCOVERY_IP],
+					    "discovery must be set in gateway mode");
+			return -EINVAL;
+		}
+		if (!amt->gw_port) {
+			NL_SET_ERR_MSG_ATTR(extack, tb[IFLA_AMT_DISCOVERY_IP],
+					    "gateway port must not be 0");
+			return -EINVAL;
+		}
+		amt->remote_ip = 0;
+		amt->discovery_ip = nla_get_in_addr(data[IFLA_AMT_DISCOVERY_IP]);
+		if (ipv4_is_loopback(amt->discovery_ip) ||
+		    ipv4_is_multicast(amt->discovery_ip)) {
+			NL_SET_ERR_MSG_ATTR(extack, tb[IFLA_AMT_DISCOVERY_IP],
+					    "discovery must be unicast");
+			return -EINVAL;
+		}
+
+		dev->needed_headroom = amt->stream_dev->needed_headroom +
+				       AMT_GW_HLEN;
+		dev->mtu = amt->stream_dev->mtu - AMT_GW_HLEN;
+		dev->max_mtu = dev->mtu;
+		dev->min_mtu = ETH_MIN_MTU + AMT_GW_HLEN;
+	}
+	amt->qi = AMT_INIT_QUERY_INTERVAL;
+
+	err = register_netdevice(dev);
+	if (err < 0) {
+		netdev_dbg(dev, "failed to register new netdev %d\n", err);
+		dev_put(amt->stream_dev);
+		return err;
+	}
+
+	err = netdev_upper_dev_link(amt->stream_dev, dev, extack);
+	if (err < 0) {
+		dev_put(amt->stream_dev);
+		unregister_netdevice(dev);
+		return err;
+	}
+
+	INIT_DELAYED_WORK(&amt->discovery_wq, amt_discovery_work);
+	INIT_DELAYED_WORK(&amt->req_wq, amt_req_work);
+	INIT_DELAYED_WORK(&amt->secret_wq, amt_secret_work);
+	INIT_LIST_HEAD(&amt->tunnel_list);
+
+	return 0;
+}
+
+static void amt_dellink(struct net_device *dev, struct list_head *head)
+{
+	struct amt_dev *amt = netdev_priv(dev);
+
+	unregister_netdevice_queue(dev, head);
+	netdev_upper_dev_unlink(amt->stream_dev, dev);
+	dev_put(amt->stream_dev);
+}
+
+static size_t amt_get_size(const struct net_device *dev)
+{
+	return nla_total_size(sizeof(__u32)) + /* IFLA_AMT_MODE */
+	       nla_total_size(sizeof(__u16)) + /* IFLA_AMT_RELAY_PORT */
+	       nla_total_size(sizeof(__u16)) + /* IFLA_AMT_GATEWAY_PORT */
+	       nla_total_size(sizeof(__u32)) + /* IFLA_AMT_LINK */
+	       nla_total_size(sizeof(__u32)) + /* IFLA_MAX_TUNNELS */
+	       nla_total_size(sizeof(struct iphdr)) + /* IFLA_AMT_DISCOVERY_IP */
+	       nla_total_size(sizeof(struct iphdr)) + /* IFLA_AMT_REMOTE_IP */
+	       nla_total_size(sizeof(struct iphdr)); /* IFLA_AMT_LOCAL_IP */
+}
+
+static int amt_fill_info(struct sk_buff *skb, const struct net_device *dev)
+{
+	struct amt_dev *amt = netdev_priv(dev);
+
+	if (nla_put_u32(skb, IFLA_AMT_MODE, amt->mode))
+		goto nla_put_failure;
+	if (nla_put_be16(skb, IFLA_AMT_RELAY_PORT, amt->relay_port))
+		goto nla_put_failure;
+	if (nla_put_be16(skb, IFLA_AMT_GATEWAY_PORT, amt->gw_port))
+		goto nla_put_failure;
+	if (amt->stream_dev)
+		if (nla_put_u32(skb, IFLA_AMT_LINK, amt->stream_dev->ifindex))
+			goto nla_put_failure;
+	if (nla_put_in_addr(skb, IFLA_AMT_LOCAL_IP, amt->local_ip))
+		goto nla_put_failure;
+	if (nla_put_in_addr(skb, IFLA_AMT_DISCOVERY_IP, amt->discovery_ip))
+		goto nla_put_failure;
+	if (amt->remote_ip)
+		if (nla_put_in_addr(skb, IFLA_AMT_REMOTE_IP, amt->remote_ip))
+			goto nla_put_failure;
+
+	return 0;
+
+nla_put_failure:
+	return -EMSGSIZE;
+}
+
+static struct rtnl_link_ops amt_link_ops __read_mostly = {
+	.kind		= "amt",
+	.maxtype	= IFLA_AMT_MAX,
+	.policy		= amt_policy,
+	.priv_size	= sizeof(struct amt_dev),
+	.setup		= amt_link_setup,
+	.validate	= amt_validate,
+	.newlink	= amt_newlink,
+	.dellink	= amt_dellink,
+	.get_size       = amt_get_size,
+	.fill_info      = amt_fill_info,
+};
+
+static struct net_device *amt_lookup_upper_dev(struct net_device *dev)
+{
+	struct net_device *upper_dev;
+	struct amt_dev *amt;
+
+	for_each_netdev(dev_net(dev), upper_dev) {
+		if (netif_is_amt(upper_dev)) {
+			amt = netdev_priv(upper_dev);
+			if (amt->stream_dev == dev)
+				return upper_dev;
+		}
+	}
+
+	return NULL;
+}
+
+static int amt_device_event(struct notifier_block *unused,
+			    unsigned long event, void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+	struct net_device *upper_dev;
+	struct amt_dev *amt;
+	LIST_HEAD(list);
+	int new_mtu;
+
+	upper_dev = amt_lookup_upper_dev(dev);
+	if (!upper_dev)
+		return NOTIFY_DONE;
+	amt = netdev_priv(upper_dev);
+
+	switch (event) {
+	case NETDEV_UNREGISTER:
+		amt_dellink(amt->dev, &list);
+		unregister_netdevice_many(&list);
+		break;
+	case NETDEV_CHANGEMTU:
+		if (amt->mode == AMT_MODE_RELAY)
+			new_mtu = dev->mtu - AMT_RELAY_HLEN;
+		else
+			new_mtu = dev->mtu - AMT_GW_HLEN;
+		amt_change_mtu(amt->dev, new_mtu);
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block amt_notifier_block __read_mostly = {
+	.notifier_call = amt_device_event,
+};
+
+static int __init amt_init(void)
+{
+	int err;
+
+	err = register_netdevice_notifier(&amt_notifier_block);
+	if (err < 0)
+		goto err;
+
+	err = rtnl_link_register(&amt_link_ops);
+	if (err < 0)
+		goto unregister_notifier;
+
+	amt_wq = alloc_workqueue("amt", WQ_UNBOUND, 1);
+	if (!amt_wq)
+		goto rtnl_unregister;
+
+	spin_lock_init(&source_gc_lock);
+	spin_lock_bh(&source_gc_lock);
+	INIT_DELAYED_WORK(&source_gc_wq, amt_source_gc_work);
+	mod_delayed_work(amt_wq, &source_gc_wq,
+			 msecs_to_jiffies(AMT_GC_INTERVAL));
+	spin_unlock_bh(&source_gc_lock);
+
+	return 0;
+
+rtnl_unregister:
+	rtnl_link_unregister(&amt_link_ops);
+unregister_notifier:
+	unregister_netdevice_notifier(&amt_notifier_block);
+err:
+	pr_err("error loading AMT module loaded\n");
+	return err;
+}
+late_initcall(amt_init);
+
+static void __exit amt_fini(void)
+{
+	rtnl_link_unregister(&amt_link_ops);
+	unregister_netdevice_notifier(&amt_notifier_block);
+	flush_delayed_work(&source_gc_wq);
+	__amt_source_gc_work();
+	destroy_workqueue(amt_wq);
+}
+module_exit(amt_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Taehee Yoo <ap420073@gmail.com>");
+MODULE_ALIAS_RTNL_LINK("amt");
diff --git a/include/net/amt.h b/include/net/amt.h
new file mode 100644
index 000000000000..4c764ef50b45
--- /dev/null
+++ b/include/net/amt.h
@@ -0,0 +1,377 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (c) 2021 Taehee Yoo <ap420073@gmail.com>
+ */
+#ifndef _NET_AMT_H_
+#define _NET_AMT_H_
+
+#include <linux/siphash.h>
+#include <linux/workqueue.h>
+#include <linux/jhash.h>
+
+enum amt_msg_type {
+	AMT_MSG_DISCOVERY = 1,
+	AMT_MSG_ADVERTISEMENT,
+	AMT_MSG_REQUEST,
+	AMT_MSG_MEMBERSHIP_QUERY,
+	AMT_MSG_MEMBERSHIP_UPDATE,
+	AMT_MSG_MULTICAST_DATA,
+	AMT_MSG_TEATDOWM,
+	__AMT_MSG_MAX,
+};
+#define AMT_MSG_MAX (__AMT_MSG_MAX - 1)
+
+enum amt_ops {
+	/* A*B */
+	AMT_OPS_INT,
+	/* A+B */
+	AMT_OPS_UNI,
+	/* A-B */
+	AMT_OPS_SUB,
+	/* B-A */
+	AMT_OPS_SUB_REV,
+	__AMT_OPS_MAX,
+};
+#define AMT_OPS_MAX (__AMT_OPS_MAX - 1)
+
+enum amt_filter {
+	AMT_FILTER_FWD,
+	AMT_FILTER_D_FWD,
+	AMT_FILTER_FWD_NEW,
+	AMT_FILTER_D_FWD_NEW,
+	AMT_FILTER_ALL,
+	AMT_FILTER_NONE_NEW,
+	AMT_FILTER_BOTH,
+	AMT_FILTER_BOTH_NEW,
+	__AMT_FILTER_MAX,
+};
+#define AMT_FILTER_MAX (__AMT_FILTER_MAX - 1)
+
+enum amt_act {
+	AMT_ACT_GMI,
+	AMT_ACT_GMI_ZERO,
+	AMT_ACT_GT,
+	AMT_ACT_STATUS_FWD_NEW,
+	AMT_ACT_STATUS_D_FWD_NEW,
+	AMT_ACT_STATUS_NONE_NEW,
+	__AMT_ACT_MAX,
+};
+#define AMT_ACT_MAX (__AMT_ACT_MAX - 1)
+
+enum amt_status {
+	AMT_STATUS_INIT,
+	AMT_STATUS_SENT_DISCOVERY,
+	AMT_STATUS_RECEIVED_DISCOVERY,
+	AMT_STATUS_SENT_ADVERTISEMENT,
+	AMT_STATUS_RECEIVED_ADVERTISEMENT,
+	AMT_STATUS_SENT_REQUEST,
+	AMT_STATUS_RECEIVED_REQUEST,
+	AMT_STATUS_SENT_QUERY,
+	AMT_STATUS_RECEIVED_QUERY,
+	AMT_STATUS_SENT_UPDATE,
+	AMT_STATUS_RECEIVED_UPDATE,
+	__AMT_STATUS_MAX,
+};
+#define AMT_STATUS_MAX (__AMT_STATUS_MAX - 1)
+
+struct amt_header {
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+	u8 type:4,
+	   version:4;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+	u8 version:4,
+	   type:4;
+#else
+#error  "Please fix <asm/byteorder.h>"
+#endif
+} __packed;
+
+struct amt_header_discovery {
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+	u32	type:4,
+		version:4,
+		reserved:24;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+	u32	version:4,
+		type:4,
+		reserved:24;
+#else
+#error  "Please fix <asm/byteorder.h>"
+#endif
+	__be32	nonce;
+} __packed;
+
+struct amt_header_advertisement {
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+	u32	type:4,
+		version:4,
+		reserved:24;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+	u32	version:4,
+		type:4,
+		reserved:24;
+#else
+#error  "Please fix <asm/byteorder.h>"
+#endif
+	__be32	nonce;
+	__be32	ip4;
+} __packed;
+
+struct amt_header_request {
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+	u32	type:4,
+		version:4,
+		reserved1:7,
+		p:1,
+		reserved2:16;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+	u32	version:4,
+		type:4,
+		p:1,
+		reserved1:7;
+		reserved2:16;
+#else
+#error  "Please fix <asm/byteorder.h>"
+#endif
+	__be32	nonce;
+} __packed;
+
+struct amt_header_membership_query {
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+	u64	type:4,
+		version:4,
+		reserved:6,
+		l:1,
+		g:1,
+		response_mac:48;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+	u64	version:4,
+		type:4,
+		g:1,
+		l:1,
+		reserved:6,
+		response_mac:48;
+#else
+#error  "Please fix <asm/byteorder.h>"
+#endif
+	__be32	nonce;
+} __packed;
+
+struct amt_header_membership_update {
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+	u64	type:4,
+		version:4,
+		reserved:8,
+		response_mac:48;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+	u64	version:4,
+		type:4,
+		reserved:8,
+		response_mac:48;
+#else
+#error  "Please fix <asm/byteorder.h>"
+#endif
+	__be32	nonce;
+} __packed;
+
+struct amt_header_mcast_data {
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+	u16	type:4,
+		version:4,
+		reserved:8;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+	u16	version:4,
+		type:4,
+		reserved:8;
+#else
+#error  "Please fix <asm/byteorder.h>"
+#endif
+} __packed;
+
+struct amt_headers {
+	union {
+		struct amt_header_discovery discovery;
+		struct amt_header_advertisement advertisement;
+		struct amt_header_request request;
+		struct amt_header_membership_query query;
+		struct amt_header_membership_update update;
+		struct amt_header_mcast_data data;
+	};
+} __packed;
+
+struct amt_gw_headers {
+	union {
+		struct amt_header_discovery discovery;
+		struct amt_header_request request;
+		struct amt_header_membership_update update;
+	};
+} __packed;
+
+struct amt_relay_headers {
+	union {
+		struct amt_header_advertisement advertisement;
+		struct amt_header_membership_query query;
+		struct amt_header_mcast_data data;
+	};
+} __packed;
+
+struct amt_skb_cb {
+	struct amt_tunnel_list *tunnel;
+};
+
+struct amt_tunnel_list {
+	struct list_head	list;
+	spinlock_t		lock;
+	struct amt_dev		*amt;
+	u32			nr_groups;
+	u32			nr_sources;
+	enum amt_status		status;
+	struct delayed_work	gc_wq;
+	__be16			source_port;
+	__be32			ip4;
+	__be32			nonce;
+	siphash_key_t		key;
+	u64			mac:48,
+				reserved:16;
+	struct rcu_head		rcu;
+	struct hlist_head	groups[];
+};
+
+union amt_addr {
+	__be32			ip4;
+#if IS_ENABLED(CONFIG_IPV6)
+	struct in6_addr		ip6;
+#endif
+};
+
+/* RFC 3810
+ *
+ * When the router is in EXCLUDE mode, the router state is represented
+ * by the notation EXCLUDE (X,Y), where X is called the "Requested List"
+ * and Y is called the "Exclude List".  All sources, except those from
+ * the Exclude List, will be forwarded by the router
+ */
+enum amt_source_status {
+	AMT_SOURCE_STATUS_NONE,
+	/* Node of Requested List */
+	AMT_SOURCE_STATUS_FWD,
+	/* Node of Exclude List */
+	AMT_SOURCE_STATUS_D_FWD,
+};
+
+/* protected by gnode->lock */
+struct amt_source_node {
+	struct hlist_node	node;
+	struct amt_group_node	*gnode;
+	struct delayed_work     source_timer;
+	union amt_addr		source_addr;
+	enum amt_source_status	status;
+#define AMT_SOURCE_OLD	0
+#define AMT_SOURCE_NEW	1
+	u8			flags;
+	struct rcu_head		rcu;
+};
+
+/* Protected by amt_tunnel_list->lock */
+struct amt_group_node {
+	struct amt_dev		*amt;
+	union amt_addr		group_addr;
+	union amt_addr		host_addr;
+	__be16			family;
+	u8			filter_mode;
+	u32			nr_sources;
+	struct amt_tunnel_list	*tunnel_list;
+	struct hlist_node	node;
+	struct delayed_work     group_timer;
+	struct rcu_head		rcu;
+	struct hlist_head	sources[];
+};
+
+struct amt_dev {
+	struct net_device       *dev;
+	struct net_device       *stream_dev;
+	struct net		*net;
+	/* Global lock for amt device */
+	spinlock_t		lock;
+	/* Used only in relay mode */
+	struct list_head        tunnel_list;
+	struct gro_cells	gro_cells;
+
+	/* Protected by RTNL */
+	struct delayed_work     discovery_wq;
+	/* Protected by RTNL */
+	struct delayed_work     req_wq;
+	/* Protected by RTNL */
+	struct delayed_work     secret_wq;
+	/* AMT status */
+	enum amt_status		status;
+	/* Generated key */
+	siphash_key_t		key;
+	struct socket	  __rcu *sock;
+	u32			max_groups;
+	u32			max_sources;
+	u32			hash_buckets;
+	u32			hash_seed;
+	/* Default 128 */
+	u32                     max_tunnels;
+	/* Default 128 */
+	u32                     nr_tunnels;
+	/* Gateway or Relay mode */
+	u32                     mode;
+	/* Default 2268 */
+	__be16			relay_port;
+	/* Default 2268 */
+	__be16			gw_port;
+	/* Outer local ip */
+	__be32			local_ip;
+	/* Outer remote ip */
+	__be32			remote_ip;
+	/* Outer discovery ip */
+	__be32			discovery_ip;
+	/* Only used in gateway mode */
+	__be32			nonce;
+	/* Gateway sent request and received query */
+	bool			ready4;
+	bool			ready6;
+	u8			req_cnt;
+	u8			qi;
+	u64			qrv;
+	u64			qri;
+	/* Used only in gateway mode */
+	u64			mac:48,
+				reserved:16;
+};
+
+#define AMT_GC_INTERVAL		(30 * 1000)
+#define AMT_MAX_GROUP		32
+#define AMT_MAX_SOURCE		128
+#define AMT_HSIZE_SHIFT		8
+#define AMT_HSIZE		(1 << AMT_HSIZE_SHIFT)
+
+#define AMT_DISCOVERY_TIMEOUT	5000
+#define AMT_INIT_REQ_TIMEOUT	1
+#define AMT_INIT_QUERY_INTERVAL	125
+#define AMT_MAX_REQ_TIMEOUT	120
+#define AMT_MAX_REQ_COUNT	3
+#define AMT_SECRET_TIMEOUT	60000
+#define IANA_AMT_UDP_PORT	2268
+#define AMT_MAX_TUNNELS         128
+#define AMT_MAX_REQS		128
+#define AMT_GW_HLEN (sizeof(struct iphdr) + \
+		     sizeof(struct udphdr) + \
+		     sizeof(struct amt_gw_headers))
+#define AMT_RELAY_HLEN (sizeof(struct iphdr) + \
+		     sizeof(struct udphdr) + \
+		     sizeof(struct amt_relay_headers))
+
+static inline bool netif_is_amt(const struct net_device *dev)
+{
+	return dev->rtnl_link_ops && !strcmp(dev->rtnl_link_ops->kind, "amt");
+}
+
+static inline u64 amt_gmi(const struct amt_dev *amt)
+{
+	return ((amt->qrv * amt->qi) + amt->qri) * 1000;
+}
+
+#endif /* _NET_AMT_H_ */
diff --git a/include/uapi/linux/amt.h b/include/uapi/linux/amt.h
new file mode 100644
index 000000000000..19876b0e08eb
--- /dev/null
+++ b/include/uapi/linux/amt.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */
+/*
+ * Copyright (c) 2021 Taehee Yoo <ap420073@gmail.com>
+ */
+#ifndef _UAPI_AMT_H_
+#define _UAPI_AMT_H_
+
+enum ifla_amt_mode {
+	AMT_MODE_GATEWAY = 0,
+	AMT_MODE_RELAY,
+	__AMT_MODE_MAX,
+};
+
+#define AMT_MODE_MAX (__AMT_MODE_MAX - 1)
+
+enum {
+	IFLA_AMT_UNSPEC,
+	IFLA_AMT_MODE,
+	IFLA_AMT_RELAY_PORT,
+	IFLA_AMT_GATEWAY_PORT,
+	IFLA_AMT_LINK,
+	IFLA_AMT_LOCAL_IP,
+	IFLA_AMT_REMOTE_IP,
+	IFLA_AMT_DISCOVERY_IP,
+	IFLA_AMT_MAX_TUNNELS,
+	__IFLA_AMT_MAX,
+};
+#define IFLA_AMT_MAX (__IFLA_AMT_MAX - 1)
+
+#endif /* _UAPI_AMT_H_ */
-- 
2.17.1


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH net-next] amt: add initial driver for Automatic Multicast Tunneling (AMT)
  2021-10-23 19:30 [PATCH net-next] amt: add initial driver for Automatic Multicast Tunneling (AMT) Taehee Yoo
@ 2021-10-26  0:46 ` Jakub Kicinski
  2021-10-26  5:00   ` Taehee Yoo
  0 siblings, 1 reply; 3+ messages in thread
From: Jakub Kicinski @ 2021-10-26  0:46 UTC (permalink / raw)
  To: Taehee Yoo; +Cc: davem, netdev, linux-kernel

On Sat, 23 Oct 2021 19:30:55 +0000 Taehee Yoo wrote:
> This is an implementation of AMT(Automatic Multicast Tunneling), RFC 7450.
> https://datatracker.ietf.org/doc/html/rfc7450
> 
> This implementation supports IGMPv2, IGMPv3, MLDv1. MLDv2, and IPv4
> underlay.


Lots of sparse warnings here, please build the new code with C=1.

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH net-next] amt: add initial driver for Automatic Multicast Tunneling (AMT)
  2021-10-26  0:46 ` Jakub Kicinski
@ 2021-10-26  5:00   ` Taehee Yoo
  0 siblings, 0 replies; 3+ messages in thread
From: Taehee Yoo @ 2021-10-26  5:00 UTC (permalink / raw)
  To: Jakub Kicinski; +Cc: davem, netdev, linux-kernel

Hi Jakub,
Thank you so much for your review!

On 10/26/21 9:46 AM, Jakub Kicinski wrote:
 > On Sat, 23 Oct 2021 19:30:55 +0000 Taehee Yoo wrote:
 >> This is an implementation of AMT(Automatic Multicast Tunneling), RFC 
7450.
 >> https://datatracker.ietf.org/doc/html/rfc7450
 >>
 >> This implementation supports IGMPv2, IGMPv3, MLDv1. MLDv2, and IPv4
 >> underlay.
 >
 >
 > Lots of sparse warnings here, please build the new code with C=1.
 >

Okay, I will fix it then send the v2.
Thanks,
Taehee

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2021-10-26  5:00 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-10-23 19:30 [PATCH net-next] amt: add initial driver for Automatic Multicast Tunneling (AMT) Taehee Yoo
2021-10-26  0:46 ` Jakub Kicinski
2021-10-26  5:00   ` Taehee Yoo

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