1 files changed, 1412 insertions, 0 deletions
diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
new file mode 100644
index 000000000000..d39e7c178460
--- /dev/null
+++ b/net/mptcp/pm_kernel.c
@@ -0,0 +1,1412 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Multipath TCP
+ *
+ * Copyright (c) 2025, Matthieu Baerts.
+ */
+
+#define pr_fmt(fmt) "MPTCP: " fmt
+
+#include <net/netns/generic.h>
+
+#include "protocol.h"
+#include "mib.h"
+#include "mptcp_pm_gen.h"
+
+static int pm_nl_pernet_id;
+
+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
+
+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));
+}
+
+static struct pm_nl_pernet *genl_info_pm_nl(struct genl_info *info)
+{
+	return pm_nl_get_pernet(genl_info_net(info));
+}
+
+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);
+
+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;
+
+	list_for_each_entry(subflow, list, node) {
+		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+		if (!((1 << inet_sk_state_load(ssk)) &
+		      (TCPF_ESTABLISHED | TCPF_SYN_SENT | TCPF_SYN_RECV)))
+			continue;
+
+		mptcp_remote_address((struct sock_common *)ssk, &cur);
+		if (mptcp_addresses_equal(&cur, daddr, daddr->port))
+			return true;
+	}
+
+	return false;
+}
+
+static bool
+select_local_address(const struct pm_nl_pernet *pernet,
+		     const struct mptcp_sock *msk,
+		     struct mptcp_pm_local *new_local)
+{
+	struct mptcp_pm_addr_entry *entry;
+	bool found = false;
+
+	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;
+
+		new_local->addr = entry->addr;
+		new_local->flags = entry->flags;
+		new_local->ifindex = entry->ifindex;
+		found = true;
+		break;
+	}
+	rcu_read_unlock();
+
+	return found;
+}
+
+static bool
+select_signal_address(struct pm_nl_pernet *pernet, const struct mptcp_sock *msk,
+		      struct mptcp_pm_local *new_local)
+{
+	struct mptcp_pm_addr_entry *entry;
+	bool found = false;
+
+	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;
+
+		new_local->addr = entry->addr;
+		new_local->flags = entry->flags;
+		new_local->ifindex = entry->ifindex;
+		found = true;
+		break;
+	}
+	rcu_read_unlock();
+
+	return found;
+}
+
+/* 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,
+					      struct mptcp_addr_info *local,
+					      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);
+	mptcp_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;
+
+		if (!mptcp_pm_addr_families_match(sk, local, &remote))
+			return 0;
+
+		msk->pm.subflows++;
+		addrs[i++] = remote;
+	} else {
+		DECLARE_BITMAP(unavail_id, MPTCP_PM_MAX_ADDR_ID + 1);
+
+		/* Forbid creation of new subflows matching existing
+		 * ones, possibly already created by incoming ADD_ADDR
+		 */
+		bitmap_zero(unavail_id, MPTCP_PM_MAX_ADDR_ID + 1);
+		mptcp_for_each_subflow(msk, subflow)
+			if (READ_ONCE(subflow->local_id) == local->id)
+				__set_bit(subflow->remote_id, unavail_id);
+
+		mptcp_for_each_subflow(msk, subflow) {
+			ssk = mptcp_subflow_tcp_sock(subflow);
+			mptcp_remote_address((struct sock_common *)ssk, &addrs[i]);
+			addrs[i].id = READ_ONCE(subflow->remote_id);
+			if (deny_id0 && !addrs[i].id)
+				continue;
+
+			if (test_bit(addrs[i].id, unavail_id))
+				continue;
+
+			if (!mptcp_pm_addr_families_match(sk, local, &addrs[i]))
+				continue;
+
+			if (msk->pm.subflows < subflows_max) {
+				/* forbid creating multiple address towards
+				 * this id
+				 */
+				__set_bit(addrs[i].id, unavail_id);
+				msk->pm.subflows++;
+				i++;
+			}
+		}
+	}
+
+	return i;
+}
+
+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_rcu(entry, &pernet->local_addr_list, list,
+				lockdep_is_held(&pernet->lock)) {
+		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)
+{
+	struct mptcp_pm_addr_entry *entry;
+
+	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list,
+				lockdep_is_held(&pernet->lock)) {
+		if (mptcp_addresses_equal(&entry->addr, info, entry->addr.port))
+			return entry;
+	}
+	return NULL;
+}
+
+static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
+{
+	struct sock *sk = (struct sock *)msk;
+	unsigned int add_addr_signal_max;
+	bool signal_and_subflow = false;
+	unsigned int local_addr_max;
+	struct pm_nl_pernet *pernet;
+	struct mptcp_pm_local local;
+	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;
+
+		mptcp_local_address((struct sock_common *)msk->first, &mpc_addr);
+		rcu_read_lock();
+		entry = __lookup_addr(pernet, &mpc_addr);
+		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) {
+		/* 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 (!select_signal_address(pernet, msk, &local))
+			goto subflow;
+
+		/* If the alloc fails, we are on memory pressure, not worth
+		 * continuing, and trying to create subflows.
+		 */
+		if (!mptcp_pm_alloc_anno_list(msk, &local.addr))
+			return;
+
+		__clear_bit(local.addr.id, msk->pm.id_avail_bitmap);
+		msk->pm.add_addr_signaled++;
+
+		/* Special case for ID0: set the correct ID */
+		if (local.addr.id == msk->mpc_endpoint_id)
+			local.addr.id = 0;
+
+		mptcp_pm_announce_addr(msk, &local.addr, false);
+		mptcp_pm_addr_send_ack(msk);
+
+		if (local.flags & MPTCP_PM_ADDR_FLAG_SUBFLOW)
+			signal_and_subflow = true;
+	}
+
+subflow:
+	/* 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;
+
+		if (signal_and_subflow)
+			signal_and_subflow = false;
+		else if (!select_local_address(pernet, msk, &local))
+			break;
+
+		fullmesh = !!(local.flags & MPTCP_PM_ADDR_FLAG_FULLMESH);
+
+		__clear_bit(local.addr.id, msk->pm.id_avail_bitmap);
+
+		/* Special case for ID0: set the correct ID */
+		if (local.addr.id == msk->mpc_endpoint_id)
+			local.addr.id = 0;
+		else /* local_addr_used is not decr for ID 0 */
+			msk->pm.local_addr_used++;
+
+		nr = fill_remote_addresses_vec(msk, &local.addr, fullmesh, addrs);
+		if (nr == 0)
+			continue;
+
+		spin_unlock_bh(&msk->pm.lock);
+		for (i = 0; i < nr; i++)
+			__mptcp_subflow_connect(sk, &local, &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 *remote,
+					     struct mptcp_pm_local *locals)
+{
+	struct sock *sk = (struct sock *)msk;
+	struct mptcp_pm_addr_entry *entry;
+	struct mptcp_addr_info mpc_addr;
+	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);
+
+	mptcp_local_address((struct sock_common *)msk, &mpc_addr);
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
+		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_FULLMESH))
+			continue;
+
+		if (!mptcp_pm_addr_families_match(sk, &entry->addr, remote))
+			continue;
+
+		if (msk->pm.subflows < subflows_max) {
+			locals[i].addr = entry->addr;
+			locals[i].flags = entry->flags;
+			locals[i].ifindex = entry->ifindex;
+
+			/* Special case for ID0: set the correct ID */
+			if (mptcp_addresses_equal(&locals[i].addr, &mpc_addr, locals[i].addr.port))
+				locals[i].addr.id = 0;
+
+			msk->pm.subflows++;
+			i++;
+		}
+	}
+	rcu_read_unlock();
+
+	/* If the array is empty, fill in the single
+	 * 'IPADDRANY' local address
+	 */
+	if (!i) {
+		memset(&locals[i], 0, sizeof(locals[i]));
+		locals[i].addr.family =
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+			       remote->family == AF_INET6 &&
+			       ipv6_addr_v4mapped(&remote->addr6) ? AF_INET :
+#endif
+			       remote->family;
+
+		if (!mptcp_pm_addr_families_match(sk, &locals[i].addr, remote))
+			return 0;
+
+		msk->pm.subflows++;
+		i++;
+	}
+
+	return i;
+}
+
+static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
+{
+	struct mptcp_pm_local locals[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;
+	bool sf_created = false;
+	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\n",
+		 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_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, &remote, locals);
+	if (nr == 0)
+		return;
+
+	spin_unlock_bh(&msk->pm.lock);
+	for (i = 0; i < nr; i++)
+		if (__mptcp_subflow_connect(sk, &locals[i], &remote) == 0)
+			sf_created = true;
+	spin_lock_bh(&msk->pm.lock);
+
+	if (sf_created) {
+		/* add_addr_accepted is not decr for ID 0 */
+		if (remote.id)
+			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);
+	}
+}
+
+void mptcp_pm_nl_rm_addr(struct mptcp_sock *msk, u8 rm_id)
+{
+	if (rm_id && WARN_ON_ONCE(msk->pm.add_addr_accepted == 0)) {
+		/* Note: if the subflow has been closed before, this
+		 * add_addr_accepted counter will not be decremented.
+		 */
+		if (--msk->pm.add_addr_accepted < mptcp_pm_get_add_addr_accept_max(msk))
+			WRITE_ONCE(msk->pm.accept_addr, true);
+	}
+}
+
+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,
+					     bool needs_id, bool replace)
+{
+	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) {
+		ret = -ERANGE;
+		goto out;
+	}
+	if (test_bit(entry->addr.id, pernet->id_bitmap)) {
+		ret = -EBUSY;
+		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)) {
+				ret = -EEXIST;
+				goto out;
+			}
+			if (entry->addr.id)
+				goto out;
+
+			/* allow callers that only need to look up the local
+			 * addr's id to skip replacement. This allows them to
+			 * avoid calling synchronize_rcu in the packet recv
+			 * path.
+			 */
+			if (!replace) {
+				kfree(entry);
+				ret = cur->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 && needs_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 && needs_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 sock *newsk, *ssk;
+	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);
+	ssk = __mptcp_nmpc_sk(mptcp_sk(newsk));
+	release_sock(newsk);
+	if (IS_ERR(ssk))
+		return PTR_ERR(ssk);
+
+	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
+	if (ssk->sk_family == AF_INET)
+		err = inet_bind_sk(ssk, (struct sockaddr *)&addr, addrlen);
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+	else if (ssk->sk_family == AF_INET6)
+		err = inet6_bind_sk(ssk, (struct sockaddr *)&addr, addrlen);
+#endif
+	if (err)
+		return err;
+
+	/* We don't use mptcp_set_state() here because it needs to be called
+	 * under the msk socket lock. For the moment, that will not bring
+	 * anything more than only calling inet_sk_state_store(), because the
+	 * old status is known (TCP_CLOSE).
+	 */
+	inet_sk_state_store(newsk, TCP_LISTEN);
+	lock_sock(ssk);
+	WRITE_ONCE(mptcp_subflow_ctx(ssk)->pm_listener, true);
+	err = __inet_listen_sk(ssk, backlog);
+	if (!err)
+		mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CREATED);
+	release_sock(ssk);
+	return err;
+}
+
+int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk,
+			     struct mptcp_pm_addr_entry *skc)
+{
+	struct mptcp_pm_addr_entry *entry;
+	struct pm_nl_pernet *pernet;
+	int ret;
+
+	pernet = pm_nl_get_pernet_from_msk(msk);
+
+	rcu_read_lock();
+	entry = __lookup_addr(pernet, &skc->addr);
+	ret = entry ? entry->addr.id : -1;
+	rcu_read_unlock();
+	if (ret >= 0)
+		return ret;
+
+	/* address not found, add to local list */
+	entry = kmemdup(skc, sizeof(*skc), GFP_ATOMIC);
+	if (!entry)
+		return -ENOMEM;
+
+	entry->addr.port = 0;
+	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry, true, false);
+	if (ret < 0)
+		kfree(entry);
+
+	return ret;
+}
+
+bool mptcp_pm_nl_is_backup(struct mptcp_sock *msk, struct mptcp_addr_info *skc)
+{
+	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
+	struct mptcp_pm_addr_entry *entry;
+	bool backup;
+
+	rcu_read_lock();
+	entry = __lookup_addr(pernet, skc);
+	backup = entry && !!(entry->flags & MPTCP_PM_ADDR_FLAG_BACKUP);
+	rcu_read_unlock();
+
+	return backup;
+}
+
+static int mptcp_nl_add_subflow_or_signal_addr(struct net *net,
+					       struct mptcp_addr_info *addr)
+{
+	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;
+		struct mptcp_addr_info mpc_addr;
+
+		if (!READ_ONCE(msk->fully_established) ||
+		    mptcp_pm_is_userspace(msk))
+			goto next;
+
+		/* if the endp linked to the init sf is re-added with a != ID */
+		mptcp_local_address((struct sock_common *)msk, &mpc_addr);
+
+		lock_sock(sk);
+		spin_lock_bh(&msk->pm.lock);
+		if (mptcp_addresses_equal(addr, &mpc_addr, addr->port))
+			msk->mpc_endpoint_id = addr->id;
+		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 bool mptcp_pm_has_addr_attr_id(const struct nlattr *attr,
+				      struct genl_info *info)
+{
+	struct nlattr *tb[MPTCP_PM_ADDR_ATTR_MAX + 1];
+
+	if (!nla_parse_nested_deprecated(tb, MPTCP_PM_ADDR_ATTR_MAX, attr,
+					 mptcp_pm_address_nl_policy, info->extack) &&
+	    tb[MPTCP_PM_ADDR_ATTR_ID])
+		return true;
+	return false;
+}
+
+/* Add an MPTCP endpoint */
+int mptcp_pm_nl_add_addr_doit(struct sk_buff *skb, struct genl_info *info)
+{
+	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
+	struct mptcp_pm_addr_entry addr, *entry;
+	struct nlattr *attr;
+	int ret;
+
+	if (GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ENDPOINT_ADDR))
+		return -EINVAL;
+
+	attr = info->attrs[MPTCP_PM_ENDPOINT_ADDR];
+	ret = mptcp_pm_parse_entry(attr, info, true, &addr);
+	if (ret < 0)
+		return ret;
+
+	if (addr.addr.port && !address_use_port(&addr)) {
+		NL_SET_ERR_MSG_ATTR(info->extack, attr,
+				    "flags must have signal and not subflow when using port");
+		return -EINVAL;
+	}
+
+	if (addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL &&
+	    addr.flags & MPTCP_PM_ADDR_FLAG_FULLMESH) {
+		NL_SET_ERR_MSG_ATTR(info->extack, attr,
+				    "flags mustn't have both signal and fullmesh");
+		return -EINVAL;
+	}
+
+	if (addr.flags & MPTCP_PM_ADDR_FLAG_IMPLICIT) {
+		NL_SET_ERR_MSG_ATTR(info->extack, attr,
+				    "can't create IMPLICIT endpoint");
+		return -EINVAL;
+	}
+
+	entry = kmemdup(&addr, sizeof(addr), GFP_KERNEL_ACCOUNT);
+	if (!entry) {
+		GENL_SET_ERR_MSG(info, "can't allocate addr");
+		return -ENOMEM;
+	}
+
+	if (entry->addr.port) {
+		ret = mptcp_pm_nl_create_listen_socket(skb->sk, entry);
+		if (ret) {
+			GENL_SET_ERR_MSG_FMT(info, "create listen socket error: %d", ret);
+			goto out_free;
+		}
+	}
+	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry,
+						!mptcp_pm_has_addr_attr_id(attr, info),
+						true);
+	if (ret < 0) {
+		GENL_SET_ERR_MSG_FMT(info, "too many addresses or duplicate one: %d", ret);
+		goto out_free;
+	}
+
+	mptcp_nl_add_subflow_or_signal_addr(sock_net(skb->sk), &entry->addr);
+	return 0;
+
+out_free:
+	__mptcp_pm_release_addr_entry(entry);
+	return ret;
+}
+
+static u8 mptcp_endp_get_local_id(struct mptcp_sock *msk,
+				  const struct mptcp_addr_info *addr)
+{
+	return msk->mpc_endpoint_id == addr->id ? 0 : addr->id;
+}
+
+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++] = mptcp_endp_get_local_id(msk, addr);
+
+	ret = mptcp_remove_anno_list_by_saddr(msk, addr);
+	if (ret || force) {
+		spin_lock_bh(&msk->pm.lock);
+		if (ret) {
+			__set_bit(addr->id, msk->pm.id_avail_bitmap);
+			msk->pm.add_addr_signaled--;
+		}
+		mptcp_pm_remove_addr(msk, &list);
+		spin_unlock_bh(&msk->pm.lock);
+	}
+	return ret;
+}
+
+static void __mark_subflow_endp_available(struct mptcp_sock *msk, u8 id)
+{
+	/* If it was marked as used, and not ID 0, decrement local_addr_used */
+	if (!__test_and_set_bit(id ? : msk->mpc_endpoint_id, msk->pm.id_avail_bitmap) &&
+	    id && !WARN_ON_ONCE(msk->pm.local_addr_used == 0))
+		msk->pm.local_addr_used--;
+}
+
+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 = 1 };
+	long s_slot = 0, s_num = 0;
+	struct mptcp_sock *msk;
+
+	pr_debug("remove_id=%d\n", 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;
+
+		lock_sock(sk);
+		remove_subflow = mptcp_lookup_subflow_by_saddr(&msk->conn_list, addr);
+		mptcp_pm_remove_anno_addr(msk, addr, remove_subflow &&
+					  !(entry->flags & MPTCP_PM_ADDR_FLAG_IMPLICIT));
+
+		list.ids[0] = mptcp_endp_get_local_id(msk, addr);
+		if (remove_subflow) {
+			spin_lock_bh(&msk->pm.lock);
+			mptcp_pm_rm_subflow(msk, &list);
+			spin_unlock_bh(&msk->pm.lock);
+		}
+
+		if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) {
+			spin_lock_bh(&msk->pm.lock);
+			__mark_subflow_endp_available(msk, list.ids[0]);
+			spin_unlock_bh(&msk->pm.lock);
+		}
+
+		if (msk->mpc_endpoint_id == entry->addr.id)
+			msk->mpc_endpoint_id = 0;
+		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;
+
+		mptcp_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_rm_subflow(msk, &list);
+		__mark_subflow_endp_available(msk, 0);
+		spin_unlock_bh(&msk->pm.lock);
+		release_sock(sk);
+
+next:
+		sock_put(sk);
+		cond_resched();
+	}
+
+	return 0;
+}
+
+/* Remove an MPTCP endpoint */
+int mptcp_pm_nl_del_addr_doit(struct sk_buff *skb, struct genl_info *info)
+{
+	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
+	struct mptcp_pm_addr_entry addr, *entry;
+	unsigned int addr_max;
+	struct nlattr *attr;
+	int ret;
+
+	if (GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ENDPOINT_ADDR))
+		return -EINVAL;
+
+	attr = info->attrs[MPTCP_PM_ENDPOINT_ADDR];
+	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) {
+		NL_SET_ERR_MSG_ATTR(info->extack, attr, "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;
+}
+
+static void mptcp_pm_flush_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 (slist.nr < MPTCP_RM_IDS_MAX &&
+		    mptcp_lookup_subflow_by_saddr(&msk->conn_list, &entry->addr))
+			slist.ids[slist.nr++] = mptcp_endp_get_local_id(msk, &entry->addr);
+
+		if (alist.nr < MPTCP_RM_IDS_MAX &&
+		    mptcp_remove_anno_list_by_saddr(msk, &entry->addr))
+			alist.ids[alist.nr++] = mptcp_endp_get_local_id(msk, &entry->addr);
+	}
+
+	spin_lock_bh(&msk->pm.lock);
+	if (alist.nr) {
+		msk->pm.add_addr_signaled -= alist.nr;
+		mptcp_pm_remove_addr(msk, &alist);
+	}
+	if (slist.nr)
+		mptcp_pm_rm_subflow(msk, &slist);
+	/* Reset counters: maybe some subflows have been removed before */
+	bitmap_fill(msk->pm.id_avail_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
+	msk->pm.local_addr_used = 0;
+	spin_unlock_bh(&msk->pm.lock);
+}
+
+static void mptcp_nl_flush_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_flush_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;
+}
+
+int mptcp_pm_nl_flush_addrs_doit(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_flush_addrs_list(sock_net(skb->sk), &free_list);
+	synchronize_rcu();
+	__flush_addrs(&free_list);
+	return 0;
+}
+
+int mptcp_pm_nl_get_addr(u8 id, struct mptcp_pm_addr_entry *addr,
+			 struct genl_info *info)
+{
+	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
+	struct mptcp_pm_addr_entry *entry;
+	int ret = -EINVAL;
+
+	rcu_read_lock();
+	entry = __lookup_addr_by_id(pernet, id);
+	if (entry) {
+		*addr = *entry;
+		ret = 0;
+	}
+	rcu_read_unlock();
+
+	return ret;
+}
+
+int mptcp_pm_nl_dump_addr(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];
+	int i;
+
+	pernet = pm_nl_get_pernet(net);
+
+	rcu_read_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;
+
+			if (mptcp_pm_genl_fill_addr(msg, cb, entry) < 0)
+				break;
+
+			id = entry->addr.id;
+		}
+	}
+	rcu_read_unlock();
+
+	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) {
+		NL_SET_ERR_MSG_ATTR_FMT(info->extack, attr,
+					"limit greater than maximum (%u)",
+					MPTCP_PM_ADDR_MAX);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+int mptcp_pm_nl_set_limits_doit(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;
+}
+
+int mptcp_pm_nl_get_limits_doit(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++] = mptcp_endp_get_local_id(msk, addr);
+
+	spin_lock_bh(&msk->pm.lock);
+	mptcp_pm_rm_subflow(msk, &list);
+	__mark_subflow_endp_available(msk, list.ids[0]);
+	mptcp_pm_create_subflow_or_signal_addr(msk);
+	spin_unlock_bh(&msk->pm.lock);
+}
+
+static void mptcp_pm_nl_set_flags_all(struct net *net,
+				      struct mptcp_pm_addr_entry *local,
+				      u8 changed)
+{
+	u8 is_subflow = !!(local->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW);
+	u8 bkup = !!(local->flags & MPTCP_PM_ADDR_FLAG_BACKUP);
+	long s_slot = 0, s_num = 0;
+	struct mptcp_sock *msk;
+
+	if (changed == MPTCP_PM_ADDR_FLAG_FULLMESH && !is_subflow)
+		return;
+
+	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)
+			mptcp_pm_mp_prio_send_ack(msk, &local->addr, NULL, bkup);
+		/* Subflows will only be recreated if the SUBFLOW flag is set */
+		if (is_subflow && (changed & MPTCP_PM_ADDR_FLAG_FULLMESH))
+			mptcp_pm_nl_fullmesh(msk, &local->addr);
+		release_sock(sk);
+
+next:
+		sock_put(sk);
+		cond_resched();
+	}
+}
+
+int mptcp_pm_nl_set_flags(struct mptcp_pm_addr_entry *local,
+			  struct genl_info *info)
+{
+	struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
+	u8 changed, mask = MPTCP_PM_ADDR_FLAG_BACKUP |
+			   MPTCP_PM_ADDR_FLAG_FULLMESH;
+	struct net *net = genl_info_net(info);
+	struct mptcp_pm_addr_entry *entry;
+	struct pm_nl_pernet *pernet;
+	u8 lookup_by_id = 0;
+
+	pernet = pm_nl_get_pernet(net);
+
+	if (local->addr.family == AF_UNSPEC) {
+		lookup_by_id = 1;
+		if (!local->addr.id) {
+			NL_SET_ERR_MSG_ATTR(info->extack, attr,
+					    "missing address ID");
+			return -EOPNOTSUPP;
+		}
+	}
+
+	spin_lock_bh(&pernet->lock);
+	entry = lookup_by_id ? __lookup_addr_by_id(pernet, local->addr.id) :
+			       __lookup_addr(pernet, &local->addr);
+	if (!entry) {
+		spin_unlock_bh(&pernet->lock);
+		NL_SET_ERR_MSG_ATTR(info->extack, attr, "address not found");
+		return -EINVAL;
+	}
+	if ((local->flags & MPTCP_PM_ADDR_FLAG_FULLMESH) &&
+	    (entry->flags & (MPTCP_PM_ADDR_FLAG_SIGNAL |
+			     MPTCP_PM_ADDR_FLAG_IMPLICIT))) {
+		spin_unlock_bh(&pernet->lock);
+		NL_SET_ERR_MSG_ATTR(info->extack, attr, "invalid addr flags");
+		return -EINVAL;
+	}
+
+	changed = (local->flags ^ entry->flags) & mask;
+	entry->flags = (entry->flags & ~mask) | (local->flags & mask);
+	*local = *entry;
+	spin_unlock_bh(&pernet->lock);
+
+	mptcp_pm_nl_set_flags_all(net, local, changed);
+	return 0;
+}
+
+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;
+}
+
+/* Called under PM lock */
+void __mptcp_pm_kernel_worker(struct mptcp_sock *msk)
+{
+	struct mptcp_pm_data *pm = &msk->pm;
+
+	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_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);
+	}
+}
+
+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),
+};
+
+struct mptcp_pm_ops mptcp_pm_kernel = {
+	.name			= "kernel",
+	.owner			= THIS_MODULE,
+};
+
+void __init mptcp_pm_kernel_register(void)
+{
+	if (register_pernet_subsys(&mptcp_pm_pernet_ops) < 0)
+		panic("Failed to register MPTCP PM pernet subsystem.\n");
+
+	mptcp_pm_register(&mptcp_pm_kernel);
+}