Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2365 insertions, 0 deletions

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
new file mode 100644
index 000000000..980050f6b
--- /dev/null
+++ b/net/mptcp/pm_netlink.c
@@ -0,0 +1,2365 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Multipath TCP
+ *
+ * Copyright (c) 2020, Red Hat, Inc.
+ */
+
+#define pr_fmt(fmt) "MPTCP: " fmt
+
+#include <linux/inet.h>
+#include <linux/kernel.h>
+#include <net/tcp.h>
+#include <net/netns/generic.h>
+#include <net/mptcp.h>
+#include <net/genetlink.h>
+#include <uapi/linux/mptcp.h>
+
+#include "protocol.h"
+#include "mib.h"
+
+/* forward declaration */
+static struct genl_family mptcp_genl_family;
+
+static int pm_nl_pernet_id;
+
+struct mptcp_pm_add_entry {
+	struct list_head	list;
+	struct mptcp_addr_info	addr;
+	struct timer_list	add_timer;
+	struct mptcp_sock	*sock;
+	u8			retrans_times;
+};
+
+struct pm_nl_pernet {
+	/* protects pernet updates */
+	spinlock_t		lock;
+	struct list_head	local_addr_list;
+	unsigned int		addrs;
+	unsigned int		stale_loss_cnt;
+	unsigned int		add_addr_signal_max;
+	unsigned int		add_addr_accept_max;
+	unsigned int		local_addr_max;
+	unsigned int		subflows_max;
+	unsigned int		next_id;
+	DECLARE_BITMAP(id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
+};
+
+#define MPTCP_PM_ADDR_MAX	8
+#define ADD_ADDR_RETRANS_MAX	3
+
+static struct pm_nl_pernet *pm_nl_get_pernet(const struct net *net)
+{
+	return net_generic(net, pm_nl_pernet_id);
+}
+
+static struct pm_nl_pernet *
+pm_nl_get_pernet_from_msk(const struct mptcp_sock *msk)
+{
+	return pm_nl_get_pernet(sock_net((struct sock *)msk));
+}
+
+bool mptcp_addresses_equal(const struct mptcp_addr_info *a,
+			   const struct mptcp_addr_info *b, bool use_port)
+{
+	bool addr_equals = false;
+
+	if (a->family == b->family) {
+		if (a->family == AF_INET)
+			addr_equals = a->addr.s_addr == b->addr.s_addr;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+		else
+			addr_equals = !ipv6_addr_cmp(&a->addr6, &b->addr6);
+	} else if (a->family == AF_INET) {
+		if (ipv6_addr_v4mapped(&b->addr6))
+			addr_equals = a->addr.s_addr == b->addr6.s6_addr32[3];
+	} else if (b->family == AF_INET) {
+		if (ipv6_addr_v4mapped(&a->addr6))
+			addr_equals = a->addr6.s6_addr32[3] == b->addr.s_addr;
+#endif
+	}
+
+	if (!addr_equals)
+		return false;
+	if (!use_port)
+		return true;
+
+	return a->port == b->port;
+}
+
+static void local_address(const struct sock_common *skc,
+			  struct mptcp_addr_info *addr)
+{
+	addr->family = skc->skc_family;
+	addr->port = htons(skc->skc_num);
+	if (addr->family == AF_INET)
+		addr->addr.s_addr = skc->skc_rcv_saddr;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+	else if (addr->family == AF_INET6)
+		addr->addr6 = skc->skc_v6_rcv_saddr;
+#endif
+}
+
+static void remote_address(const struct sock_common *skc,
+			   struct mptcp_addr_info *addr)
+{
+	addr->family = skc->skc_family;
+	addr->port = skc->skc_dport;
+	if (addr->family == AF_INET)
+		addr->addr.s_addr = skc->skc_daddr;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+	else if (addr->family == AF_INET6)
+		addr->addr6 = skc->skc_v6_daddr;
+#endif
+}
+
+static bool lookup_subflow_by_saddr(const struct list_head *list,
+				    const struct mptcp_addr_info *saddr)
+{
+	struct mptcp_subflow_context *subflow;
+	struct mptcp_addr_info cur;
+	struct sock_common *skc;
+
+	list_for_each_entry(subflow, list, node) {
+		skc = (struct sock_common *)mptcp_subflow_tcp_sock(subflow);
+
+		local_address(skc, &cur);
+		if (mptcp_addresses_equal(&cur, saddr, saddr->port))
+			return true;
+	}
+
+	return false;
+}
+
+static bool lookup_subflow_by_daddr(const struct list_head *list,
+				    const struct mptcp_addr_info *daddr)
+{
+	struct mptcp_subflow_context *subflow;
+	struct mptcp_addr_info cur;
+	struct sock_common *skc;
+
+	list_for_each_entry(subflow, list, node) {
+		skc = (struct sock_common *)mptcp_subflow_tcp_sock(subflow);
+
+		remote_address(skc, &cur);
+		if (mptcp_addresses_equal(&cur, daddr, daddr->port))
+			return true;
+	}
+
+	return false;
+}
+
+static struct mptcp_pm_addr_entry *
+select_local_address(const struct pm_nl_pernet *pernet,
+		     const struct mptcp_sock *msk)
+{
+	const struct sock *sk = (const struct sock *)msk;
+	struct mptcp_pm_addr_entry *entry, *ret = NULL;
+
+	msk_owned_by_me(msk);
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
+		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW))
+			continue;
+
+		if (!test_bit(entry->addr.id, msk->pm.id_avail_bitmap))
+			continue;
+
+		if (entry->addr.family != sk->sk_family) {
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+			if ((entry->addr.family == AF_INET &&
+			     !ipv6_addr_v4mapped(&sk->sk_v6_daddr)) ||
+			    (sk->sk_family == AF_INET &&
+			     !ipv6_addr_v4mapped(&entry->addr.addr6)))
+#endif
+				continue;
+		}
+
+		ret = entry;
+		break;
+	}
+	rcu_read_unlock();
+	return ret;
+}
+
+static struct mptcp_pm_addr_entry *
+select_signal_address(struct pm_nl_pernet *pernet, const struct mptcp_sock *msk)
+{
+	struct mptcp_pm_addr_entry *entry, *ret = NULL;
+
+	rcu_read_lock();
+	/* do not keep any additional per socket state, just signal
+	 * the address list in order.
+	 * Note: removal from the local address list during the msk life-cycle
+	 * can lead to additional addresses not being announced.
+	 */
+	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
+		if (!test_bit(entry->addr.id, msk->pm.id_avail_bitmap))
+			continue;
+
+		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL))
+			continue;
+
+		ret = entry;
+		break;
+	}
+	rcu_read_unlock();
+	return ret;
+}
+
+unsigned int mptcp_pm_get_add_addr_signal_max(const struct mptcp_sock *msk)
+{
+	const struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
+
+	return READ_ONCE(pernet->add_addr_signal_max);
+}
+EXPORT_SYMBOL_GPL(mptcp_pm_get_add_addr_signal_max);
+
+unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk)
+{
+	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
+
+	return READ_ONCE(pernet->add_addr_accept_max);
+}
+EXPORT_SYMBOL_GPL(mptcp_pm_get_add_addr_accept_max);
+
+unsigned int mptcp_pm_get_subflows_max(const struct mptcp_sock *msk)
+{
+	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
+
+	return READ_ONCE(pernet->subflows_max);
+}
+EXPORT_SYMBOL_GPL(mptcp_pm_get_subflows_max);
+
+unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk)
+{
+	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
+
+	return READ_ONCE(pernet->local_addr_max);
+}
+EXPORT_SYMBOL_GPL(mptcp_pm_get_local_addr_max);
+
+bool mptcp_pm_nl_check_work_pending(struct mptcp_sock *msk)
+{
+	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
+
+	if (msk->pm.subflows == mptcp_pm_get_subflows_max(msk) ||
+	    (find_next_and_bit(pernet->id_bitmap, msk->pm.id_avail_bitmap,
+			       MPTCP_PM_MAX_ADDR_ID + 1, 0) == MPTCP_PM_MAX_ADDR_ID + 1)) {
+		WRITE_ONCE(msk->pm.work_pending, false);
+		return false;
+	}
+	return true;
+}
+
+struct mptcp_pm_add_entry *
+mptcp_lookup_anno_list_by_saddr(const struct mptcp_sock *msk,
+				const struct mptcp_addr_info *addr)
+{
+	struct mptcp_pm_add_entry *entry;
+
+	lockdep_assert_held(&msk->pm.lock);
+
+	list_for_each_entry(entry, &msk->pm.anno_list, list) {
+		if (mptcp_addresses_equal(&entry->addr, addr, true))
+			return entry;
+	}
+
+	return NULL;
+}
+
+bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk)
+{
+	struct mptcp_pm_add_entry *entry;
+	struct mptcp_addr_info saddr;
+	bool ret = false;
+
+	local_address((struct sock_common *)sk, &saddr);
+
+	spin_lock_bh(&msk->pm.lock);
+	list_for_each_entry(entry, &msk->pm.anno_list, list) {
+		if (mptcp_addresses_equal(&entry->addr, &saddr, true)) {
+			ret = true;
+			goto out;
+		}
+	}
+
+out:
+	spin_unlock_bh(&msk->pm.lock);
+	return ret;
+}
+
+static void mptcp_pm_add_timer(struct timer_list *timer)
+{
+	struct mptcp_pm_add_entry *entry = from_timer(entry, timer, add_timer);
+	struct mptcp_sock *msk = entry->sock;
+	struct sock *sk = (struct sock *)msk;
+
+	pr_debug("msk=%p", msk);
+
+	if (!msk)
+		return;
+
+	if (inet_sk_state_load(sk) == TCP_CLOSE)
+		return;
+
+	if (!entry->addr.id)
+		return;
+
+	if (mptcp_pm_should_add_signal_addr(msk)) {
+		sk_reset_timer(sk, timer, jiffies + TCP_RTO_MAX / 8);
+		goto out;
+	}
+
+	spin_lock_bh(&msk->pm.lock);
+
+	if (!mptcp_pm_should_add_signal_addr(msk)) {
+		pr_debug("retransmit ADD_ADDR id=%d", entry->addr.id);
+		mptcp_pm_announce_addr(msk, &entry->addr, false);
+		mptcp_pm_add_addr_send_ack(msk);
+		entry->retrans_times++;
+	}
+
+	if (entry->retrans_times < ADD_ADDR_RETRANS_MAX)
+		sk_reset_timer(sk, timer,
+			       jiffies + mptcp_get_add_addr_timeout(sock_net(sk)));
+
+	spin_unlock_bh(&msk->pm.lock);
+
+	if (entry->retrans_times == ADD_ADDR_RETRANS_MAX)
+		mptcp_pm_subflow_established(msk);
+
+out:
+	__sock_put(sk);
+}
+
+struct mptcp_pm_add_entry *
+mptcp_pm_del_add_timer(struct mptcp_sock *msk,
+		       const struct mptcp_addr_info *addr, bool check_id)
+{
+	struct mptcp_pm_add_entry *entry;
+	struct sock *sk = (struct sock *)msk;
+
+	spin_lock_bh(&msk->pm.lock);
+	entry = mptcp_lookup_anno_list_by_saddr(msk, addr);
+	if (entry && (!check_id || entry->addr.id == addr->id))
+		entry->retrans_times = ADD_ADDR_RETRANS_MAX;
+	spin_unlock_bh(&msk->pm.lock);
+
+	if (entry && (!check_id || entry->addr.id == addr->id))
+		sk_stop_timer_sync(sk, &entry->add_timer);
+
+	return entry;
+}
+
+bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk,
+			      const struct mptcp_pm_addr_entry *entry)
+{
+	struct mptcp_pm_add_entry *add_entry = NULL;
+	struct sock *sk = (struct sock *)msk;
+	struct net *net = sock_net(sk);
+
+	lockdep_assert_held(&msk->pm.lock);
+
+	add_entry = mptcp_lookup_anno_list_by_saddr(msk, &entry->addr);
+
+	if (add_entry) {
+		if (mptcp_pm_is_kernel(msk))
+			return false;
+
+		sk_reset_timer(sk, &add_entry->add_timer,
+			       jiffies + mptcp_get_add_addr_timeout(net));
+		return true;
+	}
+
+	add_entry = kmalloc(sizeof(*add_entry), GFP_ATOMIC);
+	if (!add_entry)
+		return false;
+
+	list_add(&add_entry->list, &msk->pm.anno_list);
+
+	add_entry->addr = entry->addr;
+	add_entry->sock = msk;
+	add_entry->retrans_times = 0;
+
+	timer_setup(&add_entry->add_timer, mptcp_pm_add_timer, 0);
+	sk_reset_timer(sk, &add_entry->add_timer,
+		       jiffies + mptcp_get_add_addr_timeout(net));
+
+	return true;
+}
+
+void mptcp_pm_free_anno_list(struct mptcp_sock *msk)
+{
+	struct mptcp_pm_add_entry *entry, *tmp;
+	struct sock *sk = (struct sock *)msk;
+	LIST_HEAD(free_list);
+
+	pr_debug("msk=%p", msk);
+
+	spin_lock_bh(&msk->pm.lock);
+	list_splice_init(&msk->pm.anno_list, &free_list);
+	spin_unlock_bh(&msk->pm.lock);
+
+	list_for_each_entry_safe(entry, tmp, &free_list, list) {
+		sk_stop_timer_sync(sk, &entry->add_timer);
+		kfree(entry);
+	}
+}
+
+static bool lookup_address_in_vec(const struct mptcp_addr_info *addrs, unsigned int nr,
+				  const struct mptcp_addr_info *addr)
+{
+	int i;
+
+	for (i = 0; i < nr; i++) {
+		if (addrs[i].id == addr->id)
+			return true;
+	}
+
+	return false;
+}
+
+/* Fill all the remote addresses into the array addrs[],
+ * and return the array size.
+ */
+static unsigned int fill_remote_addresses_vec(struct mptcp_sock *msk, bool fullmesh,
+					      struct mptcp_addr_info *addrs)
+{
+	bool deny_id0 = READ_ONCE(msk->pm.remote_deny_join_id0);
+	struct sock *sk = (struct sock *)msk, *ssk;
+	struct mptcp_subflow_context *subflow;
+	struct mptcp_addr_info remote = { 0 };
+	unsigned int subflows_max;
+	int i = 0;
+
+	subflows_max = mptcp_pm_get_subflows_max(msk);
+	remote_address((struct sock_common *)sk, &remote);
+
+	/* Non-fullmesh endpoint, fill in the single entry
+	 * corresponding to the primary MPC subflow remote address
+	 */
+	if (!fullmesh) {
+		if (deny_id0)
+			return 0;
+
+		msk->pm.subflows++;
+		addrs[i++] = remote;
+	} else {
+		mptcp_for_each_subflow(msk, subflow) {
+			ssk = mptcp_subflow_tcp_sock(subflow);
+			remote_address((struct sock_common *)ssk, &addrs[i]);
+			addrs[i].id = subflow->remote_id;
+			if (deny_id0 && !addrs[i].id)
+				continue;
+
+			if (!lookup_address_in_vec(addrs, i, &addrs[i]) &&
+			    msk->pm.subflows < subflows_max) {
+				msk->pm.subflows++;
+				i++;
+			}
+		}
+	}
+
+	return i;
+}
+
+static void __mptcp_pm_send_ack(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
+				bool prio, bool backup)
+{
+	struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+	bool slow;
+
+	pr_debug("send ack for %s",
+		 prio ? "mp_prio" : (mptcp_pm_should_add_signal(msk) ? "add_addr" : "rm_addr"));
+
+	slow = lock_sock_fast(ssk);
+	if (prio) {
+		if (subflow->backup != backup)
+			msk->last_snd = NULL;
+
+		subflow->send_mp_prio = 1;
+		subflow->backup = backup;
+		subflow->request_bkup = backup;
+	}
+
+	__mptcp_subflow_send_ack(ssk);
+	unlock_sock_fast(ssk, slow);
+}
+
+static void mptcp_pm_send_ack(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
+			      bool prio, bool backup)
+{
+	spin_unlock_bh(&msk->pm.lock);
+	__mptcp_pm_send_ack(msk, subflow, prio, backup);
+	spin_lock_bh(&msk->pm.lock);
+}
+
+static struct mptcp_pm_addr_entry *
+__lookup_addr_by_id(struct pm_nl_pernet *pernet, unsigned int id)
+{
+	struct mptcp_pm_addr_entry *entry;
+
+	list_for_each_entry(entry, &pernet->local_addr_list, list) {
+		if (entry->addr.id == id)
+			return entry;
+	}
+	return NULL;
+}
+
+static struct mptcp_pm_addr_entry *
+__lookup_addr(struct pm_nl_pernet *pernet, const struct mptcp_addr_info *info,
+	      bool lookup_by_id)
+{
+	struct mptcp_pm_addr_entry *entry;
+
+	list_for_each_entry(entry, &pernet->local_addr_list, list) {
+		if ((!lookup_by_id &&
+		     mptcp_addresses_equal(&entry->addr, info, entry->addr.port)) ||
+		    (lookup_by_id && entry->addr.id == info->id))
+			return entry;
+	}
+	return NULL;
+}
+
+static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
+{
+	struct sock *sk = (struct sock *)msk;
+	struct mptcp_pm_addr_entry *local;
+	unsigned int add_addr_signal_max;
+	unsigned int local_addr_max;
+	struct pm_nl_pernet *pernet;
+	unsigned int subflows_max;
+
+	pernet = pm_nl_get_pernet(sock_net(sk));
+
+	add_addr_signal_max = mptcp_pm_get_add_addr_signal_max(msk);
+	local_addr_max = mptcp_pm_get_local_addr_max(msk);
+	subflows_max = mptcp_pm_get_subflows_max(msk);
+
+	/* do lazy endpoint usage accounting for the MPC subflows */
+	if (unlikely(!(msk->pm.status & BIT(MPTCP_PM_MPC_ENDPOINT_ACCOUNTED))) && msk->first) {
+		struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(msk->first);
+		struct mptcp_pm_addr_entry *entry;
+		struct mptcp_addr_info mpc_addr;
+		bool backup = false;
+
+		local_address((struct sock_common *)msk->first, &mpc_addr);
+		rcu_read_lock();
+		entry = __lookup_addr(pernet, &mpc_addr, false);
+		if (entry) {
+			__clear_bit(entry->addr.id, msk->pm.id_avail_bitmap);
+			msk->mpc_endpoint_id = entry->addr.id;
+			backup = !!(entry->flags & MPTCP_PM_ADDR_FLAG_BACKUP);
+		}
+		rcu_read_unlock();
+
+		if (backup)
+			mptcp_pm_send_ack(msk, subflow, true, backup);
+
+		msk->pm.status |= BIT(MPTCP_PM_MPC_ENDPOINT_ACCOUNTED);
+	}
+
+	pr_debug("local %d:%d signal %d:%d subflows %d:%d\n",
+		 msk->pm.local_addr_used, local_addr_max,
+		 msk->pm.add_addr_signaled, add_addr_signal_max,
+		 msk->pm.subflows, subflows_max);
+
+	/* check first for announce */
+	if (msk->pm.add_addr_signaled < add_addr_signal_max) {
+		local = select_signal_address(pernet, msk);
+
+		/* due to racing events on both ends we can reach here while
+		 * previous add address is still running: if we invoke now
+		 * mptcp_pm_announce_addr(), that will fail and the
+		 * corresponding id will be marked as used.
+		 * Instead let the PM machinery reschedule us when the
+		 * current address announce will be completed.
+		 */
+		if (msk->pm.addr_signal & BIT(MPTCP_ADD_ADDR_SIGNAL))
+			return;
+
+		if (local) {
+			if (mptcp_pm_alloc_anno_list(msk, local)) {
+				__clear_bit(local->addr.id, msk->pm.id_avail_bitmap);
+				msk->pm.add_addr_signaled++;
+				mptcp_pm_announce_addr(msk, &local->addr, false);
+				mptcp_pm_nl_addr_send_ack(msk);
+			}
+		}
+	}
+
+	/* check if should create a new subflow */
+	while (msk->pm.local_addr_used < local_addr_max &&
+	       msk->pm.subflows < subflows_max) {
+		struct mptcp_addr_info addrs[MPTCP_PM_ADDR_MAX];
+		bool fullmesh;
+		int i, nr;
+
+		local = select_local_address(pernet, msk);
+		if (!local)
+			break;
+
+		fullmesh = !!(local->flags & MPTCP_PM_ADDR_FLAG_FULLMESH);
+
+		msk->pm.local_addr_used++;
+		nr = fill_remote_addresses_vec(msk, fullmesh, addrs);
+		if (nr)
+			__clear_bit(local->addr.id, msk->pm.id_avail_bitmap);
+		spin_unlock_bh(&msk->pm.lock);
+		for (i = 0; i < nr; i++)
+			__mptcp_subflow_connect(sk, &local->addr, &addrs[i]);
+		spin_lock_bh(&msk->pm.lock);
+	}
+	mptcp_pm_nl_check_work_pending(msk);
+}
+
+static void mptcp_pm_nl_fully_established(struct mptcp_sock *msk)
+{
+	mptcp_pm_create_subflow_or_signal_addr(msk);
+}
+
+static void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk)
+{
+	mptcp_pm_create_subflow_or_signal_addr(msk);
+}
+
+/* Fill all the local addresses into the array addrs[],
+ * and return the array size.
+ */
+static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
+					     struct mptcp_addr_info *addrs)
+{
+	struct sock *sk = (struct sock *)msk;
+	struct mptcp_pm_addr_entry *entry;
+	struct mptcp_addr_info local;
+	struct pm_nl_pernet *pernet;
+	unsigned int subflows_max;
+	int i = 0;
+
+	pernet = pm_nl_get_pernet_from_msk(msk);
+	subflows_max = mptcp_pm_get_subflows_max(msk);
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
+		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_FULLMESH))
+			continue;
+
+		if (entry->addr.family != sk->sk_family) {
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+			if ((entry->addr.family == AF_INET &&
+			     !ipv6_addr_v4mapped(&sk->sk_v6_daddr)) ||
+			    (sk->sk_family == AF_INET &&
+			     !ipv6_addr_v4mapped(&entry->addr.addr6)))
+#endif
+				continue;
+		}
+
+		if (msk->pm.subflows < subflows_max) {
+			msk->pm.subflows++;
+			addrs[i++] = entry->addr;
+		}
+	}
+	rcu_read_unlock();
+
+	/* If the array is empty, fill in the single
+	 * 'IPADDRANY' local address
+	 */
+	if (!i) {
+		memset(&local, 0, sizeof(local));
+		local.family = msk->pm.remote.family;
+
+		msk->pm.subflows++;
+		addrs[i++] = local;
+	}
+
+	return i;
+}
+
+static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
+{
+	struct mptcp_addr_info addrs[MPTCP_PM_ADDR_MAX];
+	struct sock *sk = (struct sock *)msk;
+	unsigned int add_addr_accept_max;
+	struct mptcp_addr_info remote;
+	unsigned int subflows_max;
+	int i, nr;
+
+	add_addr_accept_max = mptcp_pm_get_add_addr_accept_max(msk);
+	subflows_max = mptcp_pm_get_subflows_max(msk);
+
+	pr_debug("accepted %d:%d remote family %d",
+		 msk->pm.add_addr_accepted, add_addr_accept_max,
+		 msk->pm.remote.family);
+
+	remote = msk->pm.remote;
+	mptcp_pm_announce_addr(msk, &remote, true);
+	mptcp_pm_nl_addr_send_ack(msk);
+
+	if (lookup_subflow_by_daddr(&msk->conn_list, &remote))
+		return;
+
+	/* pick id 0 port, if none is provided the remote address */
+	if (!remote.port)
+		remote.port = sk->sk_dport;
+
+	/* connect to the specified remote address, using whatever
+	 * local address the routing configuration will pick.
+	 */
+	nr = fill_local_addresses_vec(msk, addrs);
+
+	msk->pm.add_addr_accepted++;
+	if (msk->pm.add_addr_accepted >= add_addr_accept_max ||
+	    msk->pm.subflows >= subflows_max)
+		WRITE_ONCE(msk->pm.accept_addr, false);
+
+	spin_unlock_bh(&msk->pm.lock);
+	for (i = 0; i < nr; i++)
+		__mptcp_subflow_connect(sk, &addrs[i], &remote);
+	spin_lock_bh(&msk->pm.lock);
+}
+
+void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk)
+{
+	struct mptcp_subflow_context *subflow;
+
+	msk_owned_by_me(msk);
+	lockdep_assert_held(&msk->pm.lock);
+
+	if (!mptcp_pm_should_add_signal(msk) &&
+	    !mptcp_pm_should_rm_signal(msk))
+		return;
+
+	subflow = list_first_entry_or_null(&msk->conn_list, typeof(*subflow), node);
+	if (subflow)
+		mptcp_pm_send_ack(msk, subflow, false, false);
+}
+
+int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
+				 struct mptcp_addr_info *addr,
+				 struct mptcp_addr_info *rem,
+				 u8 bkup)
+{
+	struct mptcp_subflow_context *subflow;
+
+	pr_debug("bkup=%d", bkup);
+
+	mptcp_for_each_subflow(msk, subflow) {
+		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+		struct mptcp_addr_info local, remote;
+
+		local_address((struct sock_common *)ssk, &local);
+		if (!mptcp_addresses_equal(&local, addr, addr->port))
+			continue;
+
+		if (rem && rem->family != AF_UNSPEC) {
+			remote_address((struct sock_common *)ssk, &remote);
+			if (!mptcp_addresses_equal(&remote, rem, rem->port))
+				continue;
+		}
+
+		__mptcp_pm_send_ack(msk, subflow, true, bkup);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static bool mptcp_local_id_match(const struct mptcp_sock *msk, u8 local_id, u8 id)
+{
+	return local_id == id || (!local_id && msk->mpc_endpoint_id == id);
+}
+
+static void mptcp_pm_nl_rm_addr_or_subflow(struct mptcp_sock *msk,
+					   const struct mptcp_rm_list *rm_list,
+					   enum linux_mptcp_mib_field rm_type)
+{
+	struct mptcp_subflow_context *subflow, *tmp;
+	struct sock *sk = (struct sock *)msk;
+	u8 i;
+
+	pr_debug("%s rm_list_nr %d",
+		 rm_type == MPTCP_MIB_RMADDR ? "address" : "subflow", rm_list->nr);
+
+	msk_owned_by_me(msk);
+
+	if (sk->sk_state == TCP_LISTEN)
+		return;
+
+	if (!rm_list->nr)
+		return;
+
+	if (list_empty(&msk->conn_list))
+		return;
+
+	for (i = 0; i < rm_list->nr; i++) {
+		u8 rm_id = rm_list->ids[i];
+		bool removed = false;
+
+		mptcp_for_each_subflow_safe(msk, subflow, tmp) {
+			struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+			int how = RCV_SHUTDOWN | SEND_SHUTDOWN;
+			u8 id = subflow->local_id;
+
+			if (rm_type == MPTCP_MIB_RMADDR && subflow->remote_id != rm_id)
+				continue;
+			if (rm_type == MPTCP_MIB_RMSUBFLOW && !mptcp_local_id_match(msk, id, rm_id))
+				continue;
+
+			pr_debug(" -> %s rm_list_ids[%d]=%u local_id=%u remote_id=%u mpc_id=%u",
+				 rm_type == MPTCP_MIB_RMADDR ? "address" : "subflow",
+				 i, rm_id, subflow->local_id, subflow->remote_id,
+				 msk->mpc_endpoint_id);
+			spin_unlock_bh(&msk->pm.lock);
+			mptcp_subflow_shutdown(sk, ssk, how);
+
+			/* the following takes care of updating the subflows counter */
+			mptcp_close_ssk(sk, ssk, subflow);
+			spin_lock_bh(&msk->pm.lock);
+
+			removed = true;
+			__MPTCP_INC_STATS(sock_net(sk), rm_type);
+		}
+		if (rm_type == MPTCP_MIB_RMSUBFLOW)
+			__set_bit(rm_id ? rm_id : msk->mpc_endpoint_id, msk->pm.id_avail_bitmap);
+		if (!removed)
+			continue;
+
+		if (!mptcp_pm_is_kernel(msk))
+			continue;
+
+		if (rm_type == MPTCP_MIB_RMADDR) {
+			msk->pm.add_addr_accepted--;
+			WRITE_ONCE(msk->pm.accept_addr, true);
+		} else if (rm_type == MPTCP_MIB_RMSUBFLOW) {
+			msk->pm.local_addr_used--;
+		}
+	}
+}
+
+static void mptcp_pm_nl_rm_addr_received(struct mptcp_sock *msk)
+{
+	mptcp_pm_nl_rm_addr_or_subflow(msk, &msk->pm.rm_list_rx, MPTCP_MIB_RMADDR);
+}
+
+void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk,
+				     const struct mptcp_rm_list *rm_list)
+{
+	mptcp_pm_nl_rm_addr_or_subflow(msk, rm_list, MPTCP_MIB_RMSUBFLOW);
+}
+
+void mptcp_pm_nl_work(struct mptcp_sock *msk)
+{
+	struct mptcp_pm_data *pm = &msk->pm;
+
+	msk_owned_by_me(msk);
+
+	if (!(pm->status & MPTCP_PM_WORK_MASK))
+		return;
+
+	spin_lock_bh(&msk->pm.lock);
+
+	pr_debug("msk=%p status=%x", msk, pm->status);
+	if (pm->status & BIT(MPTCP_PM_ADD_ADDR_RECEIVED)) {
+		pm->status &= ~BIT(MPTCP_PM_ADD_ADDR_RECEIVED);
+		mptcp_pm_nl_add_addr_received(msk);
+	}
+	if (pm->status & BIT(MPTCP_PM_ADD_ADDR_SEND_ACK)) {
+		pm->status &= ~BIT(MPTCP_PM_ADD_ADDR_SEND_ACK);
+		mptcp_pm_nl_addr_send_ack(msk);
+	}
+	if (pm->status & BIT(MPTCP_PM_RM_ADDR_RECEIVED)) {
+		pm->status &= ~BIT(MPTCP_PM_RM_ADDR_RECEIVED);
+		mptcp_pm_nl_rm_addr_received(msk);
+	}
+	if (pm->status & BIT(MPTCP_PM_ESTABLISHED)) {
+		pm->status &= ~BIT(MPTCP_PM_ESTABLISHED);
+		mptcp_pm_nl_fully_established(msk);
+	}
+	if (pm->status & BIT(MPTCP_PM_SUBFLOW_ESTABLISHED)) {
+		pm->status &= ~BIT(MPTCP_PM_SUBFLOW_ESTABLISHED);
+		mptcp_pm_nl_subflow_established(msk);
+	}
+
+	spin_unlock_bh(&msk->pm.lock);
+}
+
+static bool address_use_port(struct mptcp_pm_addr_entry *entry)
+{
+	return (entry->flags &
+		(MPTCP_PM_ADDR_FLAG_SIGNAL | MPTCP_PM_ADDR_FLAG_SUBFLOW)) ==
+		MPTCP_PM_ADDR_FLAG_SIGNAL;
+}
+
+/* caller must ensure the RCU grace period is already elapsed */
+static void __mptcp_pm_release_addr_entry(struct mptcp_pm_addr_entry *entry)
+{
+	if (entry->lsk)
+		sock_release(entry->lsk);
+	kfree(entry);
+}
+
+static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
+					     struct mptcp_pm_addr_entry *entry)
+{
+	struct mptcp_pm_addr_entry *cur, *del_entry = NULL;
+	unsigned int addr_max;
+	int ret = -EINVAL;
+
+	spin_lock_bh(&pernet->lock);
+	/* to keep the code simple, don't do IDR-like allocation for address ID,
+	 * just bail when we exceed limits
+	 */
+	if (pernet->next_id == MPTCP_PM_MAX_ADDR_ID)
+		pernet->next_id = 1;
+	if (pernet->addrs >= MPTCP_PM_ADDR_MAX)
+		goto out;
+	if (test_bit(entry->addr.id, pernet->id_bitmap))
+		goto out;
+
+	/* do not insert duplicate address, differentiate on port only
+	 * singled addresses
+	 */
+	if (!address_use_port(entry))
+		entry->addr.port = 0;
+	list_for_each_entry(cur, &pernet->local_addr_list, list) {
+		if (mptcp_addresses_equal(&cur->addr, &entry->addr,
+					  cur->addr.port || entry->addr.port)) {
+			/* allow replacing the exiting endpoint only if such
+			 * endpoint is an implicit one and the user-space
+			 * did not provide an endpoint id
+			 */
+			if (!(cur->flags & MPTCP_PM_ADDR_FLAG_IMPLICIT))
+				goto out;
+			if (entry->addr.id)
+				goto out;
+
+			pernet->addrs--;
+			entry->addr.id = cur->addr.id;
+			list_del_rcu(&cur->list);
+			del_entry = cur;
+			break;
+		}
+	}
+
+	if (!entry->addr.id) {
+find_next:
+		entry->addr.id = find_next_zero_bit(pernet->id_bitmap,
+						    MPTCP_PM_MAX_ADDR_ID + 1,
+						    pernet->next_id);
+		if (!entry->addr.id && pernet->next_id != 1) {
+			pernet->next_id = 1;
+			goto find_next;
+		}
+	}
+
+	if (!entry->addr.id)
+		goto out;
+
+	__set_bit(entry->addr.id, pernet->id_bitmap);
+	if (entry->addr.id > pernet->next_id)
+		pernet->next_id = entry->addr.id;
+
+	if (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL) {
+		addr_max = pernet->add_addr_signal_max;
+		WRITE_ONCE(pernet->add_addr_signal_max, addr_max + 1);
+	}
+	if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) {
+		addr_max = pernet->local_addr_max;
+		WRITE_ONCE(pernet->local_addr_max, addr_max + 1);
+	}
+
+	pernet->addrs++;
+	if (!entry->addr.port)
+		list_add_tail_rcu(&entry->list, &pernet->local_addr_list);
+	else
+		list_add_rcu(&entry->list, &pernet->local_addr_list);
+	ret = entry->addr.id;
+
+out:
+	spin_unlock_bh(&pernet->lock);
+
+	/* just replaced an existing entry, free it */
+	if (del_entry) {
+		synchronize_rcu();
+		__mptcp_pm_release_addr_entry(del_entry);
+	}
+	return ret;
+}
+
+static struct lock_class_key mptcp_slock_keys[2];
+static struct lock_class_key mptcp_keys[2];
+
+static int mptcp_pm_nl_create_listen_socket(struct sock *sk,
+					    struct mptcp_pm_addr_entry *entry)
+{
+	bool is_ipv6 = sk->sk_family == AF_INET6;
+	int addrlen = sizeof(struct sockaddr_in);
+	struct sockaddr_storage addr;
+	struct socket *ssock;
+	struct sock *newsk;
+	int backlog = 1024;
+	int err;
+
+	err = sock_create_kern(sock_net(sk), entry->addr.family,
+			       SOCK_STREAM, IPPROTO_MPTCP, &entry->lsk);
+	if (err)
+		return err;
+
+	newsk = entry->lsk->sk;
+	if (!newsk)
+		return -EINVAL;
+
+	/* The subflow socket lock is acquired in a nested to the msk one
+	 * in several places, even by the TCP stack, and this msk is a kernel
+	 * socket: lockdep complains. Instead of propagating the _nested
+	 * modifiers in several places, re-init the lock class for the msk
+	 * socket to an mptcp specific one.
+	 */
+	sock_lock_init_class_and_name(newsk,
+				      is_ipv6 ? "mlock-AF_INET6" : "mlock-AF_INET",
+				      &mptcp_slock_keys[is_ipv6],
+				      is_ipv6 ? "msk_lock-AF_INET6" : "msk_lock-AF_INET",
+				      &mptcp_keys[is_ipv6]);
+
+	lock_sock(newsk);
+	ssock = __mptcp_nmpc_socket(mptcp_sk(newsk));
+	release_sock(newsk);
+	if (!ssock)
+		return -EINVAL;
+
+	mptcp_info2sockaddr(&entry->addr, &addr, entry->addr.family);
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+	if (entry->addr.family == AF_INET6)
+		addrlen = sizeof(struct sockaddr_in6);
+#endif
+	err = kernel_bind(ssock, (struct sockaddr *)&addr, addrlen);
+	if (err) {
+		pr_warn("kernel_bind error, err=%d", err);
+		return err;
+	}
+
+	inet_sk_state_store(newsk, TCP_LISTEN);
+	err = kernel_listen(ssock, backlog);
+	if (err) {
+		pr_warn("kernel_listen error, err=%d", err);
+		return err;
+	}
+
+	return 0;
+}
+
+int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
+{
+	struct mptcp_pm_addr_entry *entry;
+	struct mptcp_addr_info skc_local;
+	struct mptcp_addr_info msk_local;
+	struct pm_nl_pernet *pernet;
+	int ret = -1;
+
+	if (WARN_ON_ONCE(!msk))
+		return -1;
+
+	/* The 0 ID mapping is defined by the first subflow, copied into the msk
+	 * addr
+	 */
+	local_address((struct sock_common *)msk, &msk_local);
+	local_address((struct sock_common *)skc, &skc_local);
+	if (mptcp_addresses_equal(&msk_local, &skc_local, false))
+		return 0;
+
+	if (mptcp_pm_is_userspace(msk))
+		return mptcp_userspace_pm_get_local_id(msk, &skc_local);
+
+	pernet = pm_nl_get_pernet_from_msk(msk);
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
+		if (mptcp_addresses_equal(&entry->addr, &skc_local, entry->addr.port)) {
+			ret = entry->addr.id;
+			break;
+		}
+	}
+	rcu_read_unlock();
+	if (ret >= 0)
+		return ret;
+
+	/* address not found, add to local list */
+	entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
+	if (!entry)
+		return -ENOMEM;
+
+	entry->addr = skc_local;
+	entry->addr.id = 0;
+	entry->addr.port = 0;
+	entry->ifindex = 0;
+	entry->flags = MPTCP_PM_ADDR_FLAG_IMPLICIT;
+	entry->lsk = NULL;
+	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);
+	if (ret < 0)
+		kfree(entry);
+
+	return ret;
+}
+
+#define MPTCP_PM_CMD_GRP_OFFSET       0
+#define MPTCP_PM_EV_GRP_OFFSET        1
+
+static const struct genl_multicast_group mptcp_pm_mcgrps[] = {
+	[MPTCP_PM_CMD_GRP_OFFSET]	= { .name = MPTCP_PM_CMD_GRP_NAME, },
+	[MPTCP_PM_EV_GRP_OFFSET]        = { .name = MPTCP_PM_EV_GRP_NAME,
+					    .flags = GENL_UNS_ADMIN_PERM,
+					  },
+};
+
+static const struct nla_policy
+mptcp_pm_addr_policy[MPTCP_PM_ADDR_ATTR_MAX + 1] = {
+	[MPTCP_PM_ADDR_ATTR_FAMILY]	= { .type	= NLA_U16,	},
+	[MPTCP_PM_ADDR_ATTR_ID]		= { .type	= NLA_U8,	},
+	[MPTCP_PM_ADDR_ATTR_ADDR4]	= { .type	= NLA_U32,	},
+	[MPTCP_PM_ADDR_ATTR_ADDR6]	=
+		NLA_POLICY_EXACT_LEN(sizeof(struct in6_addr)),
+	[MPTCP_PM_ADDR_ATTR_PORT]	= { .type	= NLA_U16	},
+	[MPTCP_PM_ADDR_ATTR_FLAGS]	= { .type	= NLA_U32	},
+	[MPTCP_PM_ADDR_ATTR_IF_IDX]     = { .type	= NLA_S32	},
+};
+
+static const struct nla_policy mptcp_pm_policy[MPTCP_PM_ATTR_MAX + 1] = {
+	[MPTCP_PM_ATTR_ADDR]		=
+					NLA_POLICY_NESTED(mptcp_pm_addr_policy),
+	[MPTCP_PM_ATTR_RCV_ADD_ADDRS]	= { .type	= NLA_U32,	},
+	[MPTCP_PM_ATTR_SUBFLOWS]	= { .type	= NLA_U32,	},
+	[MPTCP_PM_ATTR_TOKEN]		= { .type	= NLA_U32,	},
+	[MPTCP_PM_ATTR_LOC_ID]		= { .type	= NLA_U8,	},
+	[MPTCP_PM_ATTR_ADDR_REMOTE]	=
+					NLA_POLICY_NESTED(mptcp_pm_addr_policy),
+};
+
+void mptcp_pm_nl_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk)
+{
+	struct mptcp_subflow_context *iter, *subflow = mptcp_subflow_ctx(ssk);
+	struct sock *sk = (struct sock *)msk;
+	unsigned int active_max_loss_cnt;
+	struct net *net = sock_net(sk);
+	unsigned int stale_loss_cnt;
+	bool slow;
+
+	stale_loss_cnt = mptcp_stale_loss_cnt(net);
+	if (subflow->stale || !stale_loss_cnt || subflow->stale_count <= stale_loss_cnt)
+		return;
+
+	/* look for another available subflow not in loss state */
+	active_max_loss_cnt = max_t(int, stale_loss_cnt - 1, 1);
+	mptcp_for_each_subflow(msk, iter) {
+		if (iter != subflow && mptcp_subflow_active(iter) &&
+		    iter->stale_count < active_max_loss_cnt) {
+			/* we have some alternatives, try to mark this subflow as idle ...*/
+			slow = lock_sock_fast(ssk);
+			if (!tcp_rtx_and_write_queues_empty(ssk)) {
+				subflow->stale = 1;
+				__mptcp_retransmit_pending_data(sk);
+				MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_SUBFLOWSTALE);
+			}
+			unlock_sock_fast(ssk, slow);
+
+			/* always try to push the pending data regardless of re-injections:
+			 * we can possibly use backup subflows now, and subflow selection
+			 * is cheap under the msk socket lock
+			 */
+			__mptcp_push_pending(sk, 0);
+			return;
+		}
+	}
+}
+
+static int mptcp_pm_family_to_addr(int family)
+{
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+	if (family == AF_INET6)
+		return MPTCP_PM_ADDR_ATTR_ADDR6;
+#endif
+	return MPTCP_PM_ADDR_ATTR_ADDR4;
+}
+
+static int mptcp_pm_parse_pm_addr_attr(struct nlattr *tb[],
+				       const struct nlattr *attr,
+				       struct genl_info *info,
+				       struct mptcp_addr_info *addr,
+				       bool require_family)
+{
+	int err, addr_addr;
+
+	if (!attr) {
+		GENL_SET_ERR_MSG(info, "missing address info");
+		return -EINVAL;
+	}
+
+	/* no validation needed - was already done via nested policy */
+	err = nla_parse_nested_deprecated(tb, MPTCP_PM_ADDR_ATTR_MAX, attr,
+					  mptcp_pm_addr_policy, info->extack);
+	if (err)
+		return err;
+
+	if (tb[MPTCP_PM_ADDR_ATTR_ID])
+		addr->id = nla_get_u8(tb[MPTCP_PM_ADDR_ATTR_ID]);
+
+	if (!tb[MPTCP_PM_ADDR_ATTR_FAMILY]) {
+		if (!require_family)
+			return err;
+
+		NL_SET_ERR_MSG_ATTR(info->extack, attr,
+				    "missing family");
+		return -EINVAL;
+	}
+
+	addr->family = nla_get_u16(tb[MPTCP_PM_ADDR_ATTR_FAMILY]);
+	if (addr->family != AF_INET
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+	    && addr->family != AF_INET6
+#endif
+	    ) {
+		NL_SET_ERR_MSG_ATTR(info->extack, attr,
+				    "unknown address family");
+		return -EINVAL;
+	}
+	addr_addr = mptcp_pm_family_to_addr(addr->family);
+	if (!tb[addr_addr]) {
+		NL_SET_ERR_MSG_ATTR(info->extack, attr,
+				    "missing address data");
+		return -EINVAL;
+	}
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+	if (addr->family == AF_INET6)
+		addr->addr6 = nla_get_in6_addr(tb[addr_addr]);
+	else
+#endif
+		addr->addr.s_addr = nla_get_in_addr(tb[addr_addr]);
+
+	if (tb[MPTCP_PM_ADDR_ATTR_PORT])
+		addr->port = htons(nla_get_u16(tb[MPTCP_PM_ADDR_ATTR_PORT]));
+
+	return err;
+}
+
+int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info,
+			struct mptcp_addr_info *addr)
+{
+	struct nlattr *tb[MPTCP_PM_ADDR_ATTR_MAX + 1];
+
+	memset(addr, 0, sizeof(*addr));
+
+	return mptcp_pm_parse_pm_addr_attr(tb, attr, info, addr, true);
+}
+
+int mptcp_pm_parse_entry(struct nlattr *attr, struct genl_info *info,
+			 bool require_family,
+			 struct mptcp_pm_addr_entry *entry)
+{
+	struct nlattr *tb[MPTCP_PM_ADDR_ATTR_MAX + 1];
+	int err;
+
+	memset(entry, 0, sizeof(*entry));
+
+	err = mptcp_pm_parse_pm_addr_attr(tb, attr, info, &entry->addr, require_family);
+	if (err)
+		return err;
+
+	if (tb[MPTCP_PM_ADDR_ATTR_IF_IDX]) {
+		u32 val = nla_get_s32(tb[MPTCP_PM_ADDR_ATTR_IF_IDX]);
+
+		entry->ifindex = val;
+	}
+
+	if (tb[MPTCP_PM_ADDR_ATTR_FLAGS])
+		entry->flags = nla_get_u32(tb[MPTCP_PM_ADDR_ATTR_FLAGS]);
+
+	if (tb[MPTCP_PM_ADDR_ATTR_PORT])
+		entry->addr.port = htons(nla_get_u16(tb[MPTCP_PM_ADDR_ATTR_PORT]));
+
+	return 0;
+}
+
+static struct pm_nl_pernet *genl_info_pm_nl(struct genl_info *info)
+{
+	return pm_nl_get_pernet(genl_info_net(info));
+}
+
+static int mptcp_nl_add_subflow_or_signal_addr(struct net *net)
+{
+	struct mptcp_sock *msk;
+	long s_slot = 0, s_num = 0;
+
+	while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
+		struct sock *sk = (struct sock *)msk;
+
+		if (!READ_ONCE(msk->fully_established) ||
+		    mptcp_pm_is_userspace(msk))
+			goto next;
+
+		lock_sock(sk);
+		spin_lock_bh(&msk->pm.lock);
+		mptcp_pm_create_subflow_or_signal_addr(msk);
+		spin_unlock_bh(&msk->pm.lock);
+		release_sock(sk);
+
+next:
+		sock_put(sk);
+		cond_resched();
+	}
+
+	return 0;
+}
+
+static int mptcp_nl_cmd_add_addr(struct sk_buff *skb, struct genl_info *info)
+{
+	struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
+	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
+	struct mptcp_pm_addr_entry addr, *entry;
+	int ret;
+
+	ret = mptcp_pm_parse_entry(attr, info, true, &addr);
+	if (ret < 0)
+		return ret;
+
+	if (addr.addr.port && !(addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL)) {
+		GENL_SET_ERR_MSG(info, "flags must have signal when using port");
+		return -EINVAL;
+	}
+
+	if (addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL &&
+	    addr.flags & MPTCP_PM_ADDR_FLAG_FULLMESH) {
+		GENL_SET_ERR_MSG(info, "flags mustn't have both signal and fullmesh");
+		return -EINVAL;
+	}
+
+	if (addr.flags & MPTCP_PM_ADDR_FLAG_IMPLICIT) {
+		GENL_SET_ERR_MSG(info, "can't create IMPLICIT endpoint");
+		return -EINVAL;
+	}
+
+	entry = kzalloc(sizeof(*entry), GFP_KERNEL_ACCOUNT);
+	if (!entry) {
+		GENL_SET_ERR_MSG(info, "can't allocate addr");
+		return -ENOMEM;
+	}
+
+	*entry = addr;
+	if (entry->addr.port) {
+		ret = mptcp_pm_nl_create_listen_socket(skb->sk, entry);
+		if (ret) {
+			GENL_SET_ERR_MSG(info, "create listen socket error");
+			goto out_free;
+		}
+	}
+	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);
+	if (ret < 0) {
+		GENL_SET_ERR_MSG(info, "too many addresses or duplicate one");
+		goto out_free;
+	}
+
+	mptcp_nl_add_subflow_or_signal_addr(sock_net(skb->sk));
+	return 0;
+
+out_free:
+	__mptcp_pm_release_addr_entry(entry);
+	return ret;
+}
+
+int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id,
+					 u8 *flags, int *ifindex)
+{
+	struct mptcp_pm_addr_entry *entry;
+	struct sock *sk = (struct sock *)msk;
+	struct net *net = sock_net(sk);
+
+	*flags = 0;
+	*ifindex = 0;
+
+	if (id) {
+		if (mptcp_pm_is_userspace(msk))
+			return mptcp_userspace_pm_get_flags_and_ifindex_by_id(msk,
+									      id,
+									      flags,
+									      ifindex);
+
+		rcu_read_lock();
+		entry = __lookup_addr_by_id(pm_nl_get_pernet(net), id);
+		if (entry) {
+			*flags = entry->flags;
+			*ifindex = entry->ifindex;
+		}
+		rcu_read_unlock();
+	}
+
+	return 0;
+}
+
+static bool remove_anno_list_by_saddr(struct mptcp_sock *msk,
+				      const struct mptcp_addr_info *addr)
+{
+	struct mptcp_pm_add_entry *entry;
+
+	entry = mptcp_pm_del_add_timer(msk, addr, false);
+	if (entry) {
+		list_del(&entry->list);
+		kfree(entry);
+		return true;
+	}
+
+	return false;
+}
+
+static bool mptcp_pm_remove_anno_addr(struct mptcp_sock *msk,
+				      const struct mptcp_addr_info *addr,
+				      bool force)
+{
+	struct mptcp_rm_list list = { .nr = 0 };
+	bool ret;
+
+	list.ids[list.nr++] = addr->id;
+
+	ret = remove_anno_list_by_saddr(msk, addr);
+	if (ret || force) {
+		spin_lock_bh(&msk->pm.lock);
+		mptcp_pm_remove_addr(msk, &list);
+		spin_unlock_bh(&msk->pm.lock);
+	}
+	return ret;
+}
+
+static int mptcp_nl_remove_subflow_and_signal_addr(struct net *net,
+						   const struct mptcp_pm_addr_entry *entry)
+{
+	const struct mptcp_addr_info *addr = &entry->addr;
+	struct mptcp_rm_list list = { .nr = 0 };
+	long s_slot = 0, s_num = 0;
+	struct mptcp_sock *msk;
+
+	pr_debug("remove_id=%d", addr->id);
+
+	list.ids[list.nr++] = addr->id;
+
+	while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
+		struct sock *sk = (struct sock *)msk;
+		bool remove_subflow;
+
+		if (mptcp_pm_is_userspace(msk))
+			goto next;
+
+		if (list_empty(&msk->conn_list)) {
+			mptcp_pm_remove_anno_addr(msk, addr, false);
+			goto next;
+		}
+
+		lock_sock(sk);
+		remove_subflow = lookup_subflow_by_saddr(&msk->conn_list, addr);
+		mptcp_pm_remove_anno_addr(msk, addr, remove_subflow &&
+					  !(entry->flags & MPTCP_PM_ADDR_FLAG_IMPLICIT));
+		if (remove_subflow)
+			mptcp_pm_remove_subflow(msk, &list);
+		release_sock(sk);
+
+next:
+		sock_put(sk);
+		cond_resched();
+	}
+
+	return 0;
+}
+
+static int mptcp_nl_remove_id_zero_address(struct net *net,
+					   struct mptcp_addr_info *addr)
+{
+	struct mptcp_rm_list list = { .nr = 0 };
+	long s_slot = 0, s_num = 0;
+	struct mptcp_sock *msk;
+
+	list.ids[list.nr++] = 0;
+
+	while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
+		struct sock *sk = (struct sock *)msk;
+		struct mptcp_addr_info msk_local;
+
+		if (list_empty(&msk->conn_list) || mptcp_pm_is_userspace(msk))
+			goto next;
+
+		local_address((struct sock_common *)msk, &msk_local);
+		if (!mptcp_addresses_equal(&msk_local, addr, addr->port))
+			goto next;
+
+		lock_sock(sk);
+		spin_lock_bh(&msk->pm.lock);
+		mptcp_pm_remove_addr(msk, &list);
+		mptcp_pm_nl_rm_subflow_received(msk, &list);
+		spin_unlock_bh(&msk->pm.lock);
+		release_sock(sk);
+
+next:
+		sock_put(sk);
+		cond_resched();
+	}
+
+	return 0;
+}
+
+static int mptcp_nl_cmd_del_addr(struct sk_buff *skb, struct genl_info *info)
+{
+	struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
+	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
+	struct mptcp_pm_addr_entry addr, *entry;
+	unsigned int addr_max;
+	int ret;
+
+	ret = mptcp_pm_parse_entry(attr, info, false, &addr);
+	if (ret < 0)
+		return ret;
+
+	/* the zero id address is special: the first address used by the msk
+	 * always gets such an id, so different subflows can have different zero
+	 * id addresses. Additionally zero id is not accounted for in id_bitmap.
+	 * Let's use an 'mptcp_rm_list' instead of the common remove code.
+	 */
+	if (addr.addr.id == 0)
+		return mptcp_nl_remove_id_zero_address(sock_net(skb->sk), &addr.addr);
+
+	spin_lock_bh(&pernet->lock);
+	entry = __lookup_addr_by_id(pernet, addr.addr.id);
+	if (!entry) {
+		GENL_SET_ERR_MSG(info, "address not found");
+		spin_unlock_bh(&pernet->lock);
+		return -EINVAL;
+	}
+	if (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL) {
+		addr_max = pernet->add_addr_signal_max;
+		WRITE_ONCE(pernet->add_addr_signal_max, addr_max - 1);
+	}
+	if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) {
+		addr_max = pernet->local_addr_max;
+		WRITE_ONCE(pernet->local_addr_max, addr_max - 1);
+	}
+
+	pernet->addrs--;
+	list_del_rcu(&entry->list);
+	__clear_bit(entry->addr.id, pernet->id_bitmap);
+	spin_unlock_bh(&pernet->lock);
+
+	mptcp_nl_remove_subflow_and_signal_addr(sock_net(skb->sk), entry);
+	synchronize_rcu();
+	__mptcp_pm_release_addr_entry(entry);
+
+	return ret;
+}
+
+void mptcp_pm_remove_addrs(struct mptcp_sock *msk, struct list_head *rm_list)
+{
+	struct mptcp_rm_list alist = { .nr = 0 };
+	struct mptcp_pm_addr_entry *entry;
+
+	list_for_each_entry(entry, rm_list, list) {
+		if ((remove_anno_list_by_saddr(msk, &entry->addr) ||
+		     lookup_subflow_by_saddr(&msk->conn_list, &entry->addr)) &&
+		    alist.nr < MPTCP_RM_IDS_MAX)
+			alist.ids[alist.nr++] = entry->addr.id;
+	}
+
+	if (alist.nr) {
+		spin_lock_bh(&msk->pm.lock);
+		mptcp_pm_remove_addr(msk, &alist);
+		spin_unlock_bh(&msk->pm.lock);
+	}
+}
+
+void mptcp_pm_remove_addrs_and_subflows(struct mptcp_sock *msk,
+					struct list_head *rm_list)
+{
+	struct mptcp_rm_list alist = { .nr = 0 }, slist = { .nr = 0 };
+	struct mptcp_pm_addr_entry *entry;
+
+	list_for_each_entry(entry, rm_list, list) {
+		if (lookup_subflow_by_saddr(&msk->conn_list, &entry->addr) &&
+		    slist.nr < MPTCP_RM_IDS_MAX)
+			slist.ids[slist.nr++] = entry->addr.id;
+
+		if (remove_anno_list_by_saddr(msk, &entry->addr) &&
+		    alist.nr < MPTCP_RM_IDS_MAX)
+			alist.ids[alist.nr++] = entry->addr.id;
+	}
+
+	if (alist.nr) {
+		spin_lock_bh(&msk->pm.lock);
+		mptcp_pm_remove_addr(msk, &alist);
+		spin_unlock_bh(&msk->pm.lock);
+	}
+	if (slist.nr)
+		mptcp_pm_remove_subflow(msk, &slist);
+}
+
+static void mptcp_nl_remove_addrs_list(struct net *net,
+				       struct list_head *rm_list)
+{
+	long s_slot = 0, s_num = 0;
+	struct mptcp_sock *msk;
+
+	if (list_empty(rm_list))
+		return;
+
+	while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
+		struct sock *sk = (struct sock *)msk;
+
+		if (!mptcp_pm_is_userspace(msk)) {
+			lock_sock(sk);
+			mptcp_pm_remove_addrs_and_subflows(msk, rm_list);
+			release_sock(sk);
+		}
+
+		sock_put(sk);
+		cond_resched();
+	}
+}
+
+/* caller must ensure the RCU grace period is already elapsed */
+static void __flush_addrs(struct list_head *list)
+{
+	while (!list_empty(list)) {
+		struct mptcp_pm_addr_entry *cur;
+
+		cur = list_entry(list->next,
+				 struct mptcp_pm_addr_entry, list);
+		list_del_rcu(&cur->list);
+		__mptcp_pm_release_addr_entry(cur);
+	}
+}
+
+static void __reset_counters(struct pm_nl_pernet *pernet)
+{
+	WRITE_ONCE(pernet->add_addr_signal_max, 0);
+	WRITE_ONCE(pernet->add_addr_accept_max, 0);
+	WRITE_ONCE(pernet->local_addr_max, 0);
+	pernet->addrs = 0;
+}
+
+static int mptcp_nl_cmd_flush_addrs(struct sk_buff *skb, struct genl_info *info)
+{
+	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
+	LIST_HEAD(free_list);
+
+	spin_lock_bh(&pernet->lock);
+	list_splice_init(&pernet->local_addr_list, &free_list);
+	__reset_counters(pernet);
+	pernet->next_id = 1;
+	bitmap_zero(pernet->id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
+	spin_unlock_bh(&pernet->lock);
+	mptcp_nl_remove_addrs_list(sock_net(skb->sk), &free_list);
+	synchronize_rcu();
+	__flush_addrs(&free_list);
+	return 0;
+}
+
+static int mptcp_nl_fill_addr(struct sk_buff *skb,
+			      struct mptcp_pm_addr_entry *entry)
+{
+	struct mptcp_addr_info *addr = &entry->addr;
+	struct nlattr *attr;
+
+	attr = nla_nest_start(skb, MPTCP_PM_ATTR_ADDR);
+	if (!attr)
+		return -EMSGSIZE;
+
+	if (nla_put_u16(skb, MPTCP_PM_ADDR_ATTR_FAMILY, addr->family))
+		goto nla_put_failure;
+	if (nla_put_u16(skb, MPTCP_PM_ADDR_ATTR_PORT, ntohs(addr->port)))
+		goto nla_put_failure;
+	if (nla_put_u8(skb, MPTCP_PM_ADDR_ATTR_ID, addr->id))
+		goto nla_put_failure;
+	if (nla_put_u32(skb, MPTCP_PM_ADDR_ATTR_FLAGS, entry->flags))
+		goto nla_put_failure;
+	if (entry->ifindex &&
+	    nla_put_s32(skb, MPTCP_PM_ADDR_ATTR_IF_IDX, entry->ifindex))
+		goto nla_put_failure;
+
+	if (addr->family == AF_INET &&
+	    nla_put_in_addr(skb, MPTCP_PM_ADDR_ATTR_ADDR4,
+			    addr->addr.s_addr))
+		goto nla_put_failure;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+	else if (addr->family == AF_INET6 &&
+		 nla_put_in6_addr(skb, MPTCP_PM_ADDR_ATTR_ADDR6, &addr->addr6))
+		goto nla_put_failure;
+#endif
+	nla_nest_end(skb, attr);
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(skb, attr);
+	return -EMSGSIZE;
+}
+
+static int mptcp_nl_cmd_get_addr(struct sk_buff *skb, struct genl_info *info)
+{
+	struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
+	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
+	struct mptcp_pm_addr_entry addr, *entry;
+	struct sk_buff *msg;
+	void *reply;
+	int ret;
+
+	ret = mptcp_pm_parse_entry(attr, info, false, &addr);
+	if (ret < 0)
+		return ret;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	reply = genlmsg_put_reply(msg, info, &mptcp_genl_family, 0,
+				  info->genlhdr->cmd);
+	if (!reply) {
+		GENL_SET_ERR_MSG(info, "not enough space in Netlink message");
+		ret = -EMSGSIZE;
+		goto fail;
+	}
+
+	spin_lock_bh(&pernet->lock);
+	entry = __lookup_addr_by_id(pernet, addr.addr.id);
+	if (!entry) {
+		GENL_SET_ERR_MSG(info, "address not found");
+		ret = -EINVAL;
+		goto unlock_fail;
+	}
+
+	ret = mptcp_nl_fill_addr(msg, entry);
+	if (ret)
+		goto unlock_fail;
+
+	genlmsg_end(msg, reply);
+	ret = genlmsg_reply(msg, info);
+	spin_unlock_bh(&pernet->lock);
+	return ret;
+
+unlock_fail:
+	spin_unlock_bh(&pernet->lock);
+
+fail:
+	nlmsg_free(msg);
+	return ret;
+}
+
+static int mptcp_nl_cmd_dump_addrs(struct sk_buff *msg,
+				   struct netlink_callback *cb)
+{
+	struct net *net = sock_net(msg->sk);
+	struct mptcp_pm_addr_entry *entry;
+	struct pm_nl_pernet *pernet;
+	int id = cb->args[0];
+	void *hdr;
+	int i;
+
+	pernet = pm_nl_get_pernet(net);
+
+	spin_lock_bh(&pernet->lock);
+	for (i = id; i < MPTCP_PM_MAX_ADDR_ID + 1; i++) {
+		if (test_bit(i, pernet->id_bitmap)) {
+			entry = __lookup_addr_by_id(pernet, i);
+			if (!entry)
+				break;
+
+			if (entry->addr.id <= id)
+				continue;
+
+			hdr = genlmsg_put(msg, NETLINK_CB(cb->skb).portid,
+					  cb->nlh->nlmsg_seq, &mptcp_genl_family,
+					  NLM_F_MULTI, MPTCP_PM_CMD_GET_ADDR);
+			if (!hdr)
+				break;
+
+			if (mptcp_nl_fill_addr(msg, entry) < 0) {
+				genlmsg_cancel(msg, hdr);
+				break;
+			}
+
+			id = entry->addr.id;
+			genlmsg_end(msg, hdr);
+		}
+	}
+	spin_unlock_bh(&pernet->lock);
+
+	cb->args[0] = id;
+	return msg->len;
+}
+
+static int parse_limit(struct genl_info *info, int id, unsigned int *limit)
+{
+	struct nlattr *attr = info->attrs[id];
+
+	if (!attr)
+		return 0;
+
+	*limit = nla_get_u32(attr);
+	if (*limit > MPTCP_PM_ADDR_MAX) {
+		GENL_SET_ERR_MSG(info, "limit greater than maximum");
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int
+mptcp_nl_cmd_set_limits(struct sk_buff *skb, struct genl_info *info)
+{
+	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
+	unsigned int rcv_addrs, subflows;
+	int ret;
+
+	spin_lock_bh(&pernet->lock);
+	rcv_addrs = pernet->add_addr_accept_max;
+	ret = parse_limit(info, MPTCP_PM_ATTR_RCV_ADD_ADDRS, &rcv_addrs);
+	if (ret)
+		goto unlock;
+
+	subflows = pernet->subflows_max;
+	ret = parse_limit(info, MPTCP_PM_ATTR_SUBFLOWS, &subflows);
+	if (ret)
+		goto unlock;
+
+	WRITE_ONCE(pernet->add_addr_accept_max, rcv_addrs);
+	WRITE_ONCE(pernet->subflows_max, subflows);
+
+unlock:
+	spin_unlock_bh(&pernet->lock);
+	return ret;
+}
+
+static int
+mptcp_nl_cmd_get_limits(struct sk_buff *skb, struct genl_info *info)
+{
+	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
+	struct sk_buff *msg;
+	void *reply;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	reply = genlmsg_put_reply(msg, info, &mptcp_genl_family, 0,
+				  MPTCP_PM_CMD_GET_LIMITS);
+	if (!reply)
+		goto fail;
+
+	if (nla_put_u32(msg, MPTCP_PM_ATTR_RCV_ADD_ADDRS,
+			READ_ONCE(pernet->add_addr_accept_max)))
+		goto fail;
+
+	if (nla_put_u32(msg, MPTCP_PM_ATTR_SUBFLOWS,
+			READ_ONCE(pernet->subflows_max)))
+		goto fail;
+
+	genlmsg_end(msg, reply);
+	return genlmsg_reply(msg, info);
+
+fail:
+	GENL_SET_ERR_MSG(info, "not enough space in Netlink message");
+	nlmsg_free(msg);
+	return -EMSGSIZE;
+}
+
+static void mptcp_pm_nl_fullmesh(struct mptcp_sock *msk,
+				 struct mptcp_addr_info *addr)
+{
+	struct mptcp_rm_list list = { .nr = 0 };
+
+	list.ids[list.nr++] = addr->id;
+
+	spin_lock_bh(&msk->pm.lock);
+	mptcp_pm_nl_rm_subflow_received(msk, &list);
+	mptcp_pm_create_subflow_or_signal_addr(msk);
+	spin_unlock_bh(&msk->pm.lock);
+}
+
+static int mptcp_nl_set_flags(struct net *net,
+			      struct mptcp_addr_info *addr,
+			      u8 bkup, u8 changed)
+{
+	long s_slot = 0, s_num = 0;
+	struct mptcp_sock *msk;
+	int ret = -EINVAL;
+
+	while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
+		struct sock *sk = (struct sock *)msk;
+
+		if (list_empty(&msk->conn_list) || mptcp_pm_is_userspace(msk))
+			goto next;
+
+		lock_sock(sk);
+		if (changed & MPTCP_PM_ADDR_FLAG_BACKUP)
+			ret = mptcp_pm_nl_mp_prio_send_ack(msk, addr, NULL, bkup);
+		if (changed & MPTCP_PM_ADDR_FLAG_FULLMESH)
+			mptcp_pm_nl_fullmesh(msk, addr);
+		release_sock(sk);
+
+next:
+		sock_put(sk);
+		cond_resched();
+	}
+
+	return ret;
+}
+
+static int mptcp_nl_cmd_set_flags(struct sk_buff *skb, struct genl_info *info)
+{
+	struct mptcp_pm_addr_entry addr = { .addr = { .family = AF_UNSPEC }, }, *entry;
+	struct mptcp_pm_addr_entry remote = { .addr = { .family = AF_UNSPEC }, };
+	struct nlattr *attr_rem = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
+	struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN];
+	struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
+	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
+	u8 changed, mask = MPTCP_PM_ADDR_FLAG_BACKUP |
+			   MPTCP_PM_ADDR_FLAG_FULLMESH;
+	struct net *net = sock_net(skb->sk);
+	u8 bkup = 0, lookup_by_id = 0;
+	int ret;
+
+	ret = mptcp_pm_parse_entry(attr, info, false, &addr);
+	if (ret < 0)
+		return ret;
+
+	if (attr_rem) {
+		ret = mptcp_pm_parse_entry(attr_rem, info, false, &remote);
+		if (ret < 0)
+			return ret;
+	}
+
+	if (addr.flags & MPTCP_PM_ADDR_FLAG_BACKUP)
+		bkup = 1;
+	if (addr.addr.family == AF_UNSPEC) {
+		lookup_by_id = 1;
+		if (!addr.addr.id)
+			return -EOPNOTSUPP;
+	}
+
+	if (token)
+		return mptcp_userspace_pm_set_flags(sock_net(skb->sk),
+						    token, &addr, &remote, bkup);
+
+	spin_lock_bh(&pernet->lock);
+	entry = __lookup_addr(pernet, &addr.addr, lookup_by_id);
+	if (!entry) {
+		spin_unlock_bh(&pernet->lock);
+		return -EINVAL;
+	}
+	if ((addr.flags & MPTCP_PM_ADDR_FLAG_FULLMESH) &&
+	    (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL)) {
+		spin_unlock_bh(&pernet->lock);
+		return -EINVAL;
+	}
+
+	changed = (addr.flags ^ entry->flags) & mask;
+	entry->flags = (entry->flags & ~mask) | (addr.flags & mask);
+	addr = *entry;
+	spin_unlock_bh(&pernet->lock);
+
+	mptcp_nl_set_flags(net, &addr.addr, bkup, changed);
+	return 0;
+}
+
+static void mptcp_nl_mcast_send(struct net *net, struct sk_buff *nlskb, gfp_t gfp)
+{
+	genlmsg_multicast_netns(&mptcp_genl_family, net,
+				nlskb, 0, MPTCP_PM_EV_GRP_OFFSET, gfp);
+}
+
+bool mptcp_userspace_pm_active(const struct mptcp_sock *msk)
+{
+	return genl_has_listeners(&mptcp_genl_family,
+				  sock_net((const struct sock *)msk),
+				  MPTCP_PM_EV_GRP_OFFSET);
+}
+
+static int mptcp_event_add_subflow(struct sk_buff *skb, const struct sock *ssk)
+{
+	const struct inet_sock *issk = inet_sk(ssk);
+	const struct mptcp_subflow_context *sf;
+
+	if (nla_put_u16(skb, MPTCP_ATTR_FAMILY, ssk->sk_family))
+		return -EMSGSIZE;
+
+	switch (ssk->sk_family) {
+	case AF_INET:
+		if (nla_put_in_addr(skb, MPTCP_ATTR_SADDR4, issk->inet_saddr))
+			return -EMSGSIZE;
+		if (nla_put_in_addr(skb, MPTCP_ATTR_DADDR4, issk->inet_daddr))
+			return -EMSGSIZE;
+		break;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+	case AF_INET6: {
+		const struct ipv6_pinfo *np = inet6_sk(ssk);
+
+		if (nla_put_in6_addr(skb, MPTCP_ATTR_SADDR6, &np->saddr))
+			return -EMSGSIZE;
+		if (nla_put_in6_addr(skb, MPTCP_ATTR_DADDR6, &ssk->sk_v6_daddr))
+			return -EMSGSIZE;
+		break;
+	}
+#endif
+	default:
+		WARN_ON_ONCE(1);
+		return -EMSGSIZE;
+	}
+
+	if (nla_put_be16(skb, MPTCP_ATTR_SPORT, issk->inet_sport))
+		return -EMSGSIZE;
+	if (nla_put_be16(skb, MPTCP_ATTR_DPORT, issk->inet_dport))
+		return -EMSGSIZE;
+
+	sf = mptcp_subflow_ctx(ssk);
+	if (WARN_ON_ONCE(!sf))
+		return -EINVAL;
+
+	if (nla_put_u8(skb, MPTCP_ATTR_LOC_ID, sf->local_id))
+		return -EMSGSIZE;
+
+	if (nla_put_u8(skb, MPTCP_ATTR_REM_ID, sf->remote_id))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static int mptcp_event_put_token_and_ssk(struct sk_buff *skb,
+					 const struct mptcp_sock *msk,
+					 const struct sock *ssk)
+{
+	const struct sock *sk = (const struct sock *)msk;
+	const struct mptcp_subflow_context *sf;
+	u8 sk_err;
+
+	if (nla_put_u32(skb, MPTCP_ATTR_TOKEN, msk->token))
+		return -EMSGSIZE;
+
+	if (mptcp_event_add_subflow(skb, ssk))
+		return -EMSGSIZE;
+
+	sf = mptcp_subflow_ctx(ssk);
+	if (WARN_ON_ONCE(!sf))
+		return -EINVAL;
+
+	if (nla_put_u8(skb, MPTCP_ATTR_BACKUP, sf->backup))
+		return -EMSGSIZE;
+
+	if (ssk->sk_bound_dev_if &&
+	    nla_put_s32(skb, MPTCP_ATTR_IF_IDX, ssk->sk_bound_dev_if))
+		return -EMSGSIZE;
+
+	sk_err = READ_ONCE(ssk->sk_err);
+	if (sk_err && sk->sk_state == TCP_ESTABLISHED &&
+	    nla_put_u8(skb, MPTCP_ATTR_ERROR, sk_err))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static int mptcp_event_sub_established(struct sk_buff *skb,
+				       const struct mptcp_sock *msk,
+				       const struct sock *ssk)
+{
+	return mptcp_event_put_token_and_ssk(skb, msk, ssk);
+}
+
+static int mptcp_event_sub_closed(struct sk_buff *skb,
+				  const struct mptcp_sock *msk,
+				  const struct sock *ssk)
+{
+	const struct mptcp_subflow_context *sf;
+
+	if (mptcp_event_put_token_and_ssk(skb, msk, ssk))
+		return -EMSGSIZE;
+
+	sf = mptcp_subflow_ctx(ssk);
+	if (!sf->reset_seen)
+		return 0;
+
+	if (nla_put_u32(skb, MPTCP_ATTR_RESET_REASON, sf->reset_reason))
+		return -EMSGSIZE;
+
+	if (nla_put_u32(skb, MPTCP_ATTR_RESET_FLAGS, sf->reset_transient))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static int mptcp_event_created(struct sk_buff *skb,
+			       const struct mptcp_sock *msk,
+			       const struct sock *ssk)
+{
+	int err = nla_put_u32(skb, MPTCP_ATTR_TOKEN, msk->token);
+
+	if (err)
+		return err;
+
+	if (nla_put_u8(skb, MPTCP_ATTR_SERVER_SIDE, READ_ONCE(msk->pm.server_side)))
+		return -EMSGSIZE;
+
+	return mptcp_event_add_subflow(skb, ssk);
+}
+
+void mptcp_event_addr_removed(const struct mptcp_sock *msk, uint8_t id)
+{
+	struct net *net = sock_net((const struct sock *)msk);
+	struct nlmsghdr *nlh;
+	struct sk_buff *skb;
+
+	if (!genl_has_listeners(&mptcp_genl_family, net, MPTCP_PM_EV_GRP_OFFSET))
+		return;
+
+	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
+	if (!skb)
+		return;
+
+	nlh = genlmsg_put(skb, 0, 0, &mptcp_genl_family, 0, MPTCP_EVENT_REMOVED);
+	if (!nlh)
+		goto nla_put_failure;
+
+	if (nla_put_u32(skb, MPTCP_ATTR_TOKEN, msk->token))
+		goto nla_put_failure;
+
+	if (nla_put_u8(skb, MPTCP_ATTR_REM_ID, id))
+		goto nla_put_failure;
+
+	genlmsg_end(skb, nlh);
+	mptcp_nl_mcast_send(net, skb, GFP_ATOMIC);
+	return;
+
+nla_put_failure:
+	kfree_skb(skb);
+}
+
+void mptcp_event_addr_announced(const struct sock *ssk,
+				const struct mptcp_addr_info *info)
+{
+	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
+	struct net *net = sock_net(ssk);
+	struct nlmsghdr *nlh;
+	struct sk_buff *skb;
+
+	if (!genl_has_listeners(&mptcp_genl_family, net, MPTCP_PM_EV_GRP_OFFSET))
+		return;
+
+	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
+	if (!skb)
+		return;
+
+	nlh = genlmsg_put(skb, 0, 0, &mptcp_genl_family, 0,
+			  MPTCP_EVENT_ANNOUNCED);
+	if (!nlh)
+		goto nla_put_failure;
+
+	if (nla_put_u32(skb, MPTCP_ATTR_TOKEN, msk->token))
+		goto nla_put_failure;
+
+	if (nla_put_u8(skb, MPTCP_ATTR_REM_ID, info->id))
+		goto nla_put_failure;
+
+	if (nla_put_be16(skb, MPTCP_ATTR_DPORT,
+			 info->port == 0 ?
+			 inet_sk(ssk)->inet_dport :
+			 info->port))
+		goto nla_put_failure;
+
+	switch (info->family) {
+	case AF_INET:
+		if (nla_put_in_addr(skb, MPTCP_ATTR_DADDR4, info->addr.s_addr))
+			goto nla_put_failure;
+		break;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+	case AF_INET6:
+		if (nla_put_in6_addr(skb, MPTCP_ATTR_DADDR6, &info->addr6))
+			goto nla_put_failure;
+		break;
+#endif
+	default:
+		WARN_ON_ONCE(1);
+		goto nla_put_failure;
+	}
+
+	genlmsg_end(skb, nlh);
+	mptcp_nl_mcast_send(net, skb, GFP_ATOMIC);
+	return;
+
+nla_put_failure:
+	kfree_skb(skb);
+}
+
+void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
+		 const struct sock *ssk, gfp_t gfp)
+{
+	struct net *net = sock_net((const struct sock *)msk);
+	struct nlmsghdr *nlh;
+	struct sk_buff *skb;
+
+	if (!genl_has_listeners(&mptcp_genl_family, net, MPTCP_PM_EV_GRP_OFFSET))
+		return;
+
+	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, gfp);
+	if (!skb)
+		return;
+
+	nlh = genlmsg_put(skb, 0, 0, &mptcp_genl_family, 0, type);
+	if (!nlh)
+		goto nla_put_failure;
+
+	switch (type) {
+	case MPTCP_EVENT_UNSPEC:
+		WARN_ON_ONCE(1);
+		break;
+	case MPTCP_EVENT_CREATED:
+	case MPTCP_EVENT_ESTABLISHED:
+		if (mptcp_event_created(skb, msk, ssk) < 0)
+			goto nla_put_failure;
+		break;
+	case MPTCP_EVENT_CLOSED:
+		if (nla_put_u32(skb, MPTCP_ATTR_TOKEN, msk->token) < 0)
+			goto nla_put_failure;
+		break;
+	case MPTCP_EVENT_ANNOUNCED:
+	case MPTCP_EVENT_REMOVED:
+		/* call mptcp_event_addr_announced()/removed instead */
+		WARN_ON_ONCE(1);
+		break;
+	case MPTCP_EVENT_SUB_ESTABLISHED:
+	case MPTCP_EVENT_SUB_PRIORITY:
+		if (mptcp_event_sub_established(skb, msk, ssk) < 0)
+			goto nla_put_failure;
+		break;
+	case MPTCP_EVENT_SUB_CLOSED:
+		if (mptcp_event_sub_closed(skb, msk, ssk) < 0)
+			goto nla_put_failure;
+		break;
+	}
+
+	genlmsg_end(skb, nlh);
+	mptcp_nl_mcast_send(net, skb, gfp);
+	return;
+
+nla_put_failure:
+	kfree_skb(skb);
+}
+
+static const struct genl_small_ops mptcp_pm_ops[] = {
+	{
+		.cmd    = MPTCP_PM_CMD_ADD_ADDR,
+		.doit   = mptcp_nl_cmd_add_addr,
+		.flags  = GENL_UNS_ADMIN_PERM,
+	},
+	{
+		.cmd    = MPTCP_PM_CMD_DEL_ADDR,
+		.doit   = mptcp_nl_cmd_del_addr,
+		.flags  = GENL_UNS_ADMIN_PERM,
+	},
+	{
+		.cmd    = MPTCP_PM_CMD_FLUSH_ADDRS,
+		.doit   = mptcp_nl_cmd_flush_addrs,
+		.flags  = GENL_UNS_ADMIN_PERM,
+	},
+	{
+		.cmd    = MPTCP_PM_CMD_GET_ADDR,
+		.doit   = mptcp_nl_cmd_get_addr,
+		.dumpit   = mptcp_nl_cmd_dump_addrs,
+	},
+	{
+		.cmd    = MPTCP_PM_CMD_SET_LIMITS,
+		.doit   = mptcp_nl_cmd_set_limits,
+		.flags  = GENL_UNS_ADMIN_PERM,
+	},
+	{
+		.cmd    = MPTCP_PM_CMD_GET_LIMITS,
+		.doit   = mptcp_nl_cmd_get_limits,
+	},
+	{
+		.cmd    = MPTCP_PM_CMD_SET_FLAGS,
+		.doit   = mptcp_nl_cmd_set_flags,
+		.flags  = GENL_UNS_ADMIN_PERM,
+	},
+	{
+		.cmd    = MPTCP_PM_CMD_ANNOUNCE,
+		.doit   = mptcp_nl_cmd_announce,
+		.flags  = GENL_UNS_ADMIN_PERM,
+	},
+	{
+		.cmd    = MPTCP_PM_CMD_REMOVE,
+		.doit   = mptcp_nl_cmd_remove,
+		.flags  = GENL_UNS_ADMIN_PERM,
+	},
+	{
+		.cmd    = MPTCP_PM_CMD_SUBFLOW_CREATE,
+		.doit   = mptcp_nl_cmd_sf_create,
+		.flags  = GENL_UNS_ADMIN_PERM,
+	},
+	{
+		.cmd    = MPTCP_PM_CMD_SUBFLOW_DESTROY,
+		.doit   = mptcp_nl_cmd_sf_destroy,
+		.flags  = GENL_UNS_ADMIN_PERM,
+	},
+};
+
+static struct genl_family mptcp_genl_family __ro_after_init = {
+	.name		= MPTCP_PM_NAME,
+	.version	= MPTCP_PM_VER,
+	.maxattr	= MPTCP_PM_ATTR_MAX,
+	.policy		= mptcp_pm_policy,
+	.netnsok	= true,
+	.module		= THIS_MODULE,
+	.small_ops	= mptcp_pm_ops,
+	.n_small_ops	= ARRAY_SIZE(mptcp_pm_ops),
+	.resv_start_op	= MPTCP_PM_CMD_SUBFLOW_DESTROY + 1,
+	.mcgrps		= mptcp_pm_mcgrps,
+	.n_mcgrps	= ARRAY_SIZE(mptcp_pm_mcgrps),
+};
+
+static int __net_init pm_nl_init_net(struct net *net)
+{
+	struct pm_nl_pernet *pernet = pm_nl_get_pernet(net);
+
+	INIT_LIST_HEAD_RCU(&pernet->local_addr_list);
+
+	/* Cit. 2 subflows ought to be enough for anybody. */
+	pernet->subflows_max = 2;
+	pernet->next_id = 1;
+	pernet->stale_loss_cnt = 4;
+	spin_lock_init(&pernet->lock);
+
+	/* No need to initialize other pernet fields, the struct is zeroed at
+	 * allocation time.
+	 */
+
+	return 0;
+}
+
+static void __net_exit pm_nl_exit_net(struct list_head *net_list)
+{
+	struct net *net;
+
+	list_for_each_entry(net, net_list, exit_list) {
+		struct pm_nl_pernet *pernet = pm_nl_get_pernet(net);
+
+		/* net is removed from namespace list, can't race with
+		 * other modifiers, also netns core already waited for a
+		 * RCU grace period.
+		 */
+		__flush_addrs(&pernet->local_addr_list);
+	}
+}
+
+static struct pernet_operations mptcp_pm_pernet_ops = {
+	.init = pm_nl_init_net,
+	.exit_batch = pm_nl_exit_net,
+	.id = &pm_nl_pernet_id,
+	.size = sizeof(struct pm_nl_pernet),
+};
+
+void __init mptcp_pm_nl_init(void)
+{
+	if (register_pernet_subsys(&mptcp_pm_pernet_ops) < 0)
+		panic("Failed to register MPTCP PM pernet subsystem.\n");
+
+	if (genl_register_family(&mptcp_genl_family))
+		panic("Failed to register MPTCP PM netlink family\n");
+}