net/mptcp/pm_userspace.c - linux/kernel/git/herbert/crypto-2.6 - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /* Multipath TCP
  *
  * Copyright (c) 2022, Intel Corporation.
  */

 #include "protocol.h"

 void mptcp_free_local_addr_list(struct mptcp_sock *msk)
 {
 	struct mptcp_pm_addr_entry *entry, *tmp;
 	struct sock *sk = (struct sock *)msk;
 	LIST_HEAD(free_list);

 	if (!mptcp_pm_is_userspace(msk))
 		return;

 	spin_lock_bh(&msk->pm.lock);
 	list_splice_init(&msk->pm.userspace_pm_local_addr_list, &free_list);
 	spin_unlock_bh(&msk->pm.lock);

 	list_for_each_entry_safe(entry, tmp, &free_list, list) {
 		sock_kfree_s(sk, entry, sizeof(*entry));
 	}
 }

 int mptcp_userspace_pm_append_new_local_addr(struct mptcp_sock *msk,
 					     struct mptcp_pm_addr_entry *entry)
 {
 	DECLARE_BITMAP(id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
 	struct mptcp_pm_addr_entry *match = NULL;
 	struct sock *sk = (struct sock *)msk;
 	struct mptcp_pm_addr_entry *e;
 	bool addr_match = false;
 	bool id_match = false;
 	int ret = -EINVAL;

 	bitmap_zero(id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);

 	spin_lock_bh(&msk->pm.lock);
 	list_for_each_entry(e, &msk->pm.userspace_pm_local_addr_list, list) {
 		addr_match = mptcp_addresses_equal(&e->addr, &entry->addr, true);
 		if (addr_match && entry->addr.id == 0)
 			entry->addr.id = e->addr.id;
 		id_match = (e->addr.id == entry->addr.id);
 		if (addr_match && id_match) {
 			match = e;
 			break;
 		} else if (addr_match || id_match) {
 			break;
 		}
 		__set_bit(e->addr.id, id_bitmap);
 	}

 	if (!match && !addr_match && !id_match) {
 		/* Memory for the entry is allocated from the
 		 * sock option buffer.
 		 */
 		e = sock_kmalloc(sk, sizeof(*e), GFP_ATOMIC);
 		if (!e) {
 			spin_unlock_bh(&msk->pm.lock);
 			return -ENOMEM;
 		}

 		*e = *entry;
 		if (!e->addr.id)
 			e->addr.id = find_next_zero_bit(id_bitmap,
 							MPTCP_PM_MAX_ADDR_ID + 1,
 							1);
 		list_add_tail_rcu(&e->list, &msk->pm.userspace_pm_local_addr_list);
 		ret = e->addr.id;
 	} else if (match) {
 		ret = entry->addr.id;
 	}

 	spin_unlock_bh(&msk->pm.lock);
 	return ret;
 }

 int mptcp_userspace_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
 						   unsigned int id,
 						   u8 *flags, int *ifindex)
 {
 	struct mptcp_pm_addr_entry *entry, *match = NULL;

 	*flags = 0;
 	*ifindex = 0;

 	spin_lock_bh(&msk->pm.lock);
 	list_for_each_entry(entry, &msk->pm.userspace_pm_local_addr_list, list) {
 		if (id == entry->addr.id) {
 			match = entry;
 			break;
 		}
 	}
 	spin_unlock_bh(&msk->pm.lock);
 	if (match) {
 		*flags = match->flags;
 		*ifindex = match->ifindex;
 	}

 	return 0;
 }

 int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk,
 				    struct mptcp_addr_info *skc)
 {
 	struct mptcp_pm_addr_entry new_entry;
 	__be16 msk_sport =  ((struct inet_sock *)
 			     inet_sk((struct sock *)msk))->inet_sport;

 	memset(&new_entry, 0, sizeof(struct mptcp_pm_addr_entry));
 	new_entry.addr = *skc;
 	new_entry.addr.id = 0;
 	new_entry.flags = MPTCP_PM_ADDR_FLAG_IMPLICIT;

 	if (new_entry.addr.port == msk_sport)
 		new_entry.addr.port = 0;

 	return mptcp_userspace_pm_append_new_local_addr(msk, &new_entry);
 }

 int mptcp_nl_cmd_announce(struct sk_buff *skb, struct genl_info *info)
 {
 	struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN];
 	struct nlattr *addr = info->attrs[MPTCP_PM_ATTR_ADDR];
 	struct mptcp_pm_addr_entry addr_val;
 	struct mptcp_sock *msk;
 	int err = -EINVAL;
 	u32 token_val;

 	if (!addr || !token) {
 		GENL_SET_ERR_MSG(info, "missing required inputs");
 		return err;
 	}

 	token_val = nla_get_u32(token);

 	msk = mptcp_token_get_sock(sock_net(skb->sk), token_val);
 	if (!msk) {
 		NL_SET_ERR_MSG_ATTR(info->extack, token, "invalid token");
 		return err;
 	}

 	if (!mptcp_pm_is_userspace(msk)) {
 		GENL_SET_ERR_MSG(info, "invalid request; userspace PM not selected");
 		goto announce_err;
 	}

 	err = mptcp_pm_parse_entry(addr, info, true, &addr_val);
 	if (err < 0) {
 		GENL_SET_ERR_MSG(info, "error parsing local address");
 		goto announce_err;
 	}

 	if (addr_val.addr.id == 0 || !(addr_val.flags & MPTCP_PM_ADDR_FLAG_SIGNAL)) {
 		GENL_SET_ERR_MSG(info, "invalid addr id or flags");
 		goto announce_err;
 	}

 	err = mptcp_userspace_pm_append_new_local_addr(msk, &addr_val);
 	if (err < 0) {
 		GENL_SET_ERR_MSG(info, "did not match address and id");
 		goto announce_err;
 	}

 	lock_sock((struct sock *)msk);
 	spin_lock_bh(&msk->pm.lock);

 	if (mptcp_pm_alloc_anno_list(msk, &addr_val)) {
 		mptcp_pm_announce_addr(msk, &addr_val.addr, false);
 		mptcp_pm_nl_addr_send_ack(msk);
 	}

 	spin_unlock_bh(&msk->pm.lock);
 	release_sock((struct sock *)msk);

 	err = 0;
  announce_err:
 	sock_put((struct sock *)msk);
 	return err;
 }

 int mptcp_nl_cmd_remove(struct sk_buff *skb, struct genl_info *info)
 {
 	struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN];
 	struct nlattr *id = info->attrs[MPTCP_PM_ATTR_LOC_ID];
 	struct mptcp_pm_addr_entry *match = NULL;
 	struct mptcp_pm_addr_entry *entry;
 	struct mptcp_sock *msk;
 	LIST_HEAD(free_list);
 	int err = -EINVAL;
 	u32 token_val;
 	u8 id_val;

 	if (!id || !token) {
 		GENL_SET_ERR_MSG(info, "missing required inputs");
 		return err;
 	}

 	id_val = nla_get_u8(id);
 	token_val = nla_get_u32(token);

 	msk = mptcp_token_get_sock(sock_net(skb->sk), token_val);
 	if (!msk) {
 		NL_SET_ERR_MSG_ATTR(info->extack, token, "invalid token");
 		return err;
 	}

 	if (!mptcp_pm_is_userspace(msk)) {
 		GENL_SET_ERR_MSG(info, "invalid request; userspace PM not selected");
 		goto remove_err;
 	}

 	lock_sock((struct sock *)msk);

 	list_for_each_entry(entry, &msk->pm.userspace_pm_local_addr_list, list) {
 		if (entry->addr.id == id_val) {
 			match = entry;
 			break;
 		}
 	}

 	if (!match) {
 		GENL_SET_ERR_MSG(info, "address with specified id not found");
 		release_sock((struct sock *)msk);
 		goto remove_err;
 	}

 	list_move(&match->list, &free_list);

 	mptcp_pm_remove_addrs_and_subflows(msk, &free_list);

 	release_sock((struct sock *)msk);

 	list_for_each_entry_safe(match, entry, &free_list, list) {
 		sock_kfree_s((struct sock *)msk, match, sizeof(*match));
 	}

 	err = 0;
  remove_err:
 	sock_put((struct sock *)msk);
 	return err;
 }

 int mptcp_nl_cmd_sf_create(struct sk_buff *skb, struct genl_info *info)
 {
 	struct nlattr *raddr = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
 	struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN];
 	struct nlattr *laddr = info->attrs[MPTCP_PM_ATTR_ADDR];
 	struct mptcp_addr_info addr_r;
 	struct mptcp_addr_info addr_l;
 	struct mptcp_sock *msk;
 	int err = -EINVAL;
 	struct sock *sk;
 	u32 token_val;

 	if (!laddr || !raddr || !token) {
 		GENL_SET_ERR_MSG(info, "missing required inputs");
 		return err;
 	}

 	token_val = nla_get_u32(token);

 	msk = mptcp_token_get_sock(genl_info_net(info), token_val);
 	if (!msk) {
 		NL_SET_ERR_MSG_ATTR(info->extack, token, "invalid token");
 		return err;
 	}

 	if (!mptcp_pm_is_userspace(msk)) {
 		GENL_SET_ERR_MSG(info, "invalid request; userspace PM not selected");
 		goto create_err;
 	}

 	err = mptcp_pm_parse_addr(laddr, info, &addr_l);
 	if (err < 0) {
 		NL_SET_ERR_MSG_ATTR(info->extack, laddr, "error parsing local addr");
 		goto create_err;
 	}

 	if (addr_l.id == 0) {
 		NL_SET_ERR_MSG_ATTR(info->extack, laddr, "missing local addr id");
 		goto create_err;
 	}

 	err = mptcp_pm_parse_addr(raddr, info, &addr_r);
 	if (err < 0) {
 		NL_SET_ERR_MSG_ATTR(info->extack, raddr, "error parsing remote addr");
 		goto create_err;
 	}

 	sk = &msk->sk.icsk_inet.sk;
 	lock_sock(sk);

 	err = __mptcp_subflow_connect(sk, &addr_l, &addr_r);

 	release_sock(sk);

  create_err:
 	sock_put((struct sock *)msk);
 	return err;
 }

 static struct sock *mptcp_nl_find_ssk(struct mptcp_sock *msk,
 				      const struct mptcp_addr_info *local,
 				      const struct mptcp_addr_info *remote)
 {
 	struct sock *sk = &msk->sk.icsk_inet.sk;
 	struct mptcp_subflow_context *subflow;
 	struct sock *found = NULL;

 	if (local->family != remote->family)
 		return NULL;

 	lock_sock(sk);

 	mptcp_for_each_subflow(msk, subflow) {
 		const struct inet_sock *issk;
 		struct sock *ssk;

 		ssk = mptcp_subflow_tcp_sock(subflow);

 		if (local->family != ssk->sk_family)
 			continue;

 		issk = inet_sk(ssk);

 		switch (ssk->sk_family) {
 		case AF_INET:
 			if (issk->inet_saddr != local->addr.s_addr ||
 			    issk->inet_daddr != remote->addr.s_addr)
 				continue;
 			break;
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 		case AF_INET6: {
 			const struct ipv6_pinfo *pinfo = inet6_sk(ssk);

 			if (!ipv6_addr_equal(&local->addr6, &pinfo->saddr) ||
 			    !ipv6_addr_equal(&remote->addr6, &ssk->sk_v6_daddr))
 				continue;
 			break;
 		}
 #endif
 		default:
 			continue;
 		}

 		if (issk->inet_sport == local->port &&
 		    issk->inet_dport == remote->port) {
 			found = ssk;
 			goto found;
 		}
 	}

 found:
 	release_sock(sk);

 	return found;
 }

 int mptcp_nl_cmd_sf_destroy(struct sk_buff *skb, struct genl_info *info)
 {
 	struct nlattr *raddr = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
 	struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN];
 	struct nlattr *laddr = info->attrs[MPTCP_PM_ATTR_ADDR];
 	struct mptcp_addr_info addr_l;
 	struct mptcp_addr_info addr_r;
 	struct mptcp_sock *msk;
 	struct sock *sk, *ssk;
 	int err = -EINVAL;
 	u32 token_val;

 	if (!laddr || !raddr || !token) {
 		GENL_SET_ERR_MSG(info, "missing required inputs");
 		return err;
 	}

 	token_val = nla_get_u32(token);

 	msk = mptcp_token_get_sock(genl_info_net(info), token_val);
 	if (!msk) {
 		NL_SET_ERR_MSG_ATTR(info->extack, token, "invalid token");
 		return err;
 	}

 	if (!mptcp_pm_is_userspace(msk)) {
 		GENL_SET_ERR_MSG(info, "invalid request; userspace PM not selected");
 		goto destroy_err;
 	}

 	err = mptcp_pm_parse_addr(laddr, info, &addr_l);
 	if (err < 0) {
 		NL_SET_ERR_MSG_ATTR(info->extack, laddr, "error parsing local addr");
 		goto destroy_err;
 	}

 	err = mptcp_pm_parse_addr(raddr, info, &addr_r);
 	if (err < 0) {
 		NL_SET_ERR_MSG_ATTR(info->extack, raddr, "error parsing remote addr");
 		goto destroy_err;
 	}

 	if (addr_l.family != addr_r.family) {
 		GENL_SET_ERR_MSG(info, "address families do not match");
 		goto destroy_err;
 	}

 	if (!addr_l.port || !addr_r.port) {
 		GENL_SET_ERR_MSG(info, "missing local or remote port");
 		goto destroy_err;
 	}

 	sk = &msk->sk.icsk_inet.sk;
 	ssk = mptcp_nl_find_ssk(msk, &addr_l, &addr_r);
 	if (ssk) {
 		struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);

 		mptcp_subflow_shutdown(sk, ssk, RCV_SHUTDOWN | SEND_SHUTDOWN);
 		mptcp_close_ssk(sk, ssk, subflow);
 		err = 0;
 	} else {
 		err = -ESRCH;
 	}

  destroy_err:
 	sock_put((struct sock *)msk);
 	return err;
 }
	// SPDX-License-Identifier: GPL-2.0
	/* Multipath TCP
	*
	* Copyright (c) 2022, Intel Corporation.
	*/

	#include "protocol.h"

	void mptcp_free_local_addr_list(struct mptcp_sock *msk)
	{
	struct mptcp_pm_addr_entry entry, tmp;
	struct sock sk = (struct sock )msk;
	LIST_HEAD(free_list);

	if (!mptcp_pm_is_userspace(msk))
	return;

	spin_lock_bh(&msk->pm.lock);
	list_splice_init(&msk->pm.userspace_pm_local_addr_list, &free_list);
	spin_unlock_bh(&msk->pm.lock);

	list_for_each_entry_safe(entry, tmp, &free_list, list) {
	sock_kfree_s(sk, entry, sizeof(*entry));
	}
	}

	int mptcp_userspace_pm_append_new_local_addr(struct mptcp_sock *msk,
	struct mptcp_pm_addr_entry *entry)
	{
	DECLARE_BITMAP(id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
	struct mptcp_pm_addr_entry *match = NULL;
	struct sock sk = (struct sock )msk;
	struct mptcp_pm_addr_entry *e;
	bool addr_match = false;
	bool id_match = false;
	int ret = -EINVAL;

	bitmap_zero(id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);

	spin_lock_bh(&msk->pm.lock);
	list_for_each_entry(e, &msk->pm.userspace_pm_local_addr_list, list) {
	addr_match = mptcp_addresses_equal(&e->addr, &entry->addr, true);
	if (addr_match && entry->addr.id == 0)
	entry->addr.id = e->addr.id;
	id_match = (e->addr.id == entry->addr.id);
	if (addr_match && id_match) {
	match = e;
	break;
	} else if (addr_match \|\| id_match) {
	break;
	}
	__set_bit(e->addr.id, id_bitmap);
	}

	if (!match && !addr_match && !id_match) {
	/* Memory for the entry is allocated from the
	* sock option buffer.
	*/
	e = sock_kmalloc(sk, sizeof(*e), GFP_ATOMIC);
	if (!e) {
	spin_unlock_bh(&msk->pm.lock);
	return -ENOMEM;
	}

	e = entry;
	if (!e->addr.id)
	e->addr.id = find_next_zero_bit(id_bitmap,
	MPTCP_PM_MAX_ADDR_ID + 1,
	1);
	list_add_tail_rcu(&e->list, &msk->pm.userspace_pm_local_addr_list);
	ret = e->addr.id;
	} else if (match) {
	ret = entry->addr.id;
	}

	spin_unlock_bh(&msk->pm.lock);
	return ret;
	}

	int mptcp_userspace_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
	unsigned int id,
	u8 flags, int ifindex)
	{
	struct mptcp_pm_addr_entry entry, match = NULL;

	*flags = 0;
	*ifindex = 0;

	spin_lock_bh(&msk->pm.lock);
	list_for_each_entry(entry, &msk->pm.userspace_pm_local_addr_list, list) {
	if (id == entry->addr.id) {
	match = entry;
	break;
	}
	}
	spin_unlock_bh(&msk->pm.lock);
	if (match) {
	*flags = match->flags;
	*ifindex = match->ifindex;
	}

	return 0;
	}

	int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk,
	struct mptcp_addr_info *skc)
	{
	struct mptcp_pm_addr_entry new_entry;
	__be16 msk_sport = ((struct inet_sock *)
	inet_sk((struct sock *)msk))->inet_sport;

	memset(&new_entry, 0, sizeof(struct mptcp_pm_addr_entry));
	new_entry.addr = *skc;
	new_entry.addr.id = 0;
	new_entry.flags = MPTCP_PM_ADDR_FLAG_IMPLICIT;

	if (new_entry.addr.port == msk_sport)
	new_entry.addr.port = 0;

	return mptcp_userspace_pm_append_new_local_addr(msk, &new_entry);
	}

	int mptcp_nl_cmd_announce(struct sk_buff skb, struct genl_info info)
	{
	struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN];
	struct nlattr *addr = info->attrs[MPTCP_PM_ATTR_ADDR];
	struct mptcp_pm_addr_entry addr_val;
	struct mptcp_sock *msk;
	int err = -EINVAL;
	u32 token_val;

	if (!addr \|\| !token) {
	GENL_SET_ERR_MSG(info, "missing required inputs");
	return err;
	}

	token_val = nla_get_u32(token);

	msk = mptcp_token_get_sock(sock_net(skb->sk), token_val);
	if (!msk) {
	NL_SET_ERR_MSG_ATTR(info->extack, token, "invalid token");
	return err;
	}

	if (!mptcp_pm_is_userspace(msk)) {
	GENL_SET_ERR_MSG(info, "invalid request; userspace PM not selected");
	goto announce_err;
	}

	err = mptcp_pm_parse_entry(addr, info, true, &addr_val);
	if (err < 0) {
	GENL_SET_ERR_MSG(info, "error parsing local address");
	goto announce_err;
	}

	if (addr_val.addr.id == 0 \|\| !(addr_val.flags & MPTCP_PM_ADDR_FLAG_SIGNAL)) {
	GENL_SET_ERR_MSG(info, "invalid addr id or flags");
	goto announce_err;
	}

	err = mptcp_userspace_pm_append_new_local_addr(msk, &addr_val);
	if (err < 0) {
	GENL_SET_ERR_MSG(info, "did not match address and id");
	goto announce_err;
	}

	lock_sock((struct sock *)msk);
	spin_lock_bh(&msk->pm.lock);

	if (mptcp_pm_alloc_anno_list(msk, &addr_val)) {
	mptcp_pm_announce_addr(msk, &addr_val.addr, false);
	mptcp_pm_nl_addr_send_ack(msk);
	}

	spin_unlock_bh(&msk->pm.lock);
	release_sock((struct sock *)msk);

	err = 0;
	announce_err:
	sock_put((struct sock *)msk);
	return err;
	}

	int mptcp_nl_cmd_remove(struct sk_buff skb, struct genl_info info)
	{
	struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN];
	struct nlattr *id = info->attrs[MPTCP_PM_ATTR_LOC_ID];
	struct mptcp_pm_addr_entry *match = NULL;
	struct mptcp_pm_addr_entry *entry;
	struct mptcp_sock *msk;
	LIST_HEAD(free_list);
	int err = -EINVAL;
	u32 token_val;
	u8 id_val;

	if (!id \|\| !token) {
	GENL_SET_ERR_MSG(info, "missing required inputs");
	return err;
	}

	id_val = nla_get_u8(id);
	token_val = nla_get_u32(token);

	msk = mptcp_token_get_sock(sock_net(skb->sk), token_val);
	if (!msk) {
	NL_SET_ERR_MSG_ATTR(info->extack, token, "invalid token");
	return err;
	}

	if (!mptcp_pm_is_userspace(msk)) {
	GENL_SET_ERR_MSG(info, "invalid request; userspace PM not selected");
	goto remove_err;
	}

	lock_sock((struct sock *)msk);

	list_for_each_entry(entry, &msk->pm.userspace_pm_local_addr_list, list) {
	if (entry->addr.id == id_val) {
	match = entry;
	break;
	}
	}

	if (!match) {
	GENL_SET_ERR_MSG(info, "address with specified id not found");
	release_sock((struct sock *)msk);
	goto remove_err;
	}

	list_move(&match->list, &free_list);

	mptcp_pm_remove_addrs_and_subflows(msk, &free_list);

	release_sock((struct sock *)msk);

	list_for_each_entry_safe(match, entry, &free_list, list) {
	sock_kfree_s((struct sock )msk, match, sizeof(match));
	}

	err = 0;
	remove_err:
	sock_put((struct sock *)msk);
	return err;
	}

	int mptcp_nl_cmd_sf_create(struct sk_buff skb, struct genl_info info)
	{
	struct nlattr *raddr = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
	struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN];
	struct nlattr *laddr = info->attrs[MPTCP_PM_ATTR_ADDR];
	struct mptcp_addr_info addr_r;
	struct mptcp_addr_info addr_l;
	struct mptcp_sock *msk;
	int err = -EINVAL;
	struct sock *sk;
	u32 token_val;

	if (!laddr \|\| !raddr \|\| !token) {
	GENL_SET_ERR_MSG(info, "missing required inputs");
	return err;
	}

	token_val = nla_get_u32(token);

	msk = mptcp_token_get_sock(genl_info_net(info), token_val);
	if (!msk) {
	NL_SET_ERR_MSG_ATTR(info->extack, token, "invalid token");
	return err;
	}

	if (!mptcp_pm_is_userspace(msk)) {
	GENL_SET_ERR_MSG(info, "invalid request; userspace PM not selected");
	goto create_err;
	}

	err = mptcp_pm_parse_addr(laddr, info, &addr_l);
	if (err < 0) {
	NL_SET_ERR_MSG_ATTR(info->extack, laddr, "error parsing local addr");
	goto create_err;
	}

	if (addr_l.id == 0) {
	NL_SET_ERR_MSG_ATTR(info->extack, laddr, "missing local addr id");
	goto create_err;
	}

	err = mptcp_pm_parse_addr(raddr, info, &addr_r);
	if (err < 0) {
	NL_SET_ERR_MSG_ATTR(info->extack, raddr, "error parsing remote addr");
	goto create_err;
	}

	sk = &msk->sk.icsk_inet.sk;
	lock_sock(sk);

	err = __mptcp_subflow_connect(sk, &addr_l, &addr_r);

	release_sock(sk);

	create_err:
	sock_put((struct sock *)msk);
	return err;
	}

	static struct sock mptcp_nl_find_ssk(struct mptcp_sock msk,
	const struct mptcp_addr_info *local,
	const struct mptcp_addr_info *remote)
	{
	struct sock *sk = &msk->sk.icsk_inet.sk;
	struct mptcp_subflow_context *subflow;
	struct sock *found = NULL;

	if (local->family != remote->family)
	return NULL;

	lock_sock(sk);

	mptcp_for_each_subflow(msk, subflow) {
	const struct inet_sock *issk;
	struct sock *ssk;

	ssk = mptcp_subflow_tcp_sock(subflow);

	if (local->family != ssk->sk_family)
	continue;

	issk = inet_sk(ssk);

	switch (ssk->sk_family) {
	case AF_INET:
	if (issk->inet_saddr != local->addr.s_addr \|\|
	issk->inet_daddr != remote->addr.s_addr)
	continue;
	break;
	#if IS_ENABLED(CONFIG_MPTCP_IPV6)
	case AF_INET6: {
	const struct ipv6_pinfo *pinfo = inet6_sk(ssk);

	if (!ipv6_addr_equal(&local->addr6, &pinfo->saddr) \|\|
	!ipv6_addr_equal(&remote->addr6, &ssk->sk_v6_daddr))
	continue;
	break;
	}
	#endif
	default:
	continue;
	}

	if (issk->inet_sport == local->port &&
	issk->inet_dport == remote->port) {
	found = ssk;
	goto found;
	}
	}

	found:
	release_sock(sk);

	return found;
	}

	int mptcp_nl_cmd_sf_destroy(struct sk_buff skb, struct genl_info info)
	{
	struct nlattr *raddr = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
	struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN];
	struct nlattr *laddr = info->attrs[MPTCP_PM_ATTR_ADDR];
	struct mptcp_addr_info addr_l;
	struct mptcp_addr_info addr_r;
	struct mptcp_sock *msk;
	struct sock sk, ssk;
	int err = -EINVAL;
	u32 token_val;

	if (!laddr \|\| !raddr \|\| !token) {
	GENL_SET_ERR_MSG(info, "missing required inputs");
	return err;
	}

	token_val = nla_get_u32(token);

	msk = mptcp_token_get_sock(genl_info_net(info), token_val);
	if (!msk) {
	NL_SET_ERR_MSG_ATTR(info->extack, token, "invalid token");
	return err;
	}

	if (!mptcp_pm_is_userspace(msk)) {
	GENL_SET_ERR_MSG(info, "invalid request; userspace PM not selected");
	goto destroy_err;
	}

	err = mptcp_pm_parse_addr(laddr, info, &addr_l);
	if (err < 0) {
	NL_SET_ERR_MSG_ATTR(info->extack, laddr, "error parsing local addr");
	goto destroy_err;
	}

	err = mptcp_pm_parse_addr(raddr, info, &addr_r);
	if (err < 0) {
	NL_SET_ERR_MSG_ATTR(info->extack, raddr, "error parsing remote addr");
	goto destroy_err;
	}

	if (addr_l.family != addr_r.family) {
	GENL_SET_ERR_MSG(info, "address families do not match");
	goto destroy_err;
	}

	if (!addr_l.port \|\| !addr_r.port) {
	GENL_SET_ERR_MSG(info, "missing local or remote port");
	goto destroy_err;
	}

	sk = &msk->sk.icsk_inet.sk;
	ssk = mptcp_nl_find_ssk(msk, &addr_l, &addr_r);
	if (ssk) {
	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);

	mptcp_subflow_shutdown(sk, ssk, RCV_SHUTDOWN \| SEND_SHUTDOWN);
	mptcp_close_ssk(sk, ssk, subflow);
	err = 0;
	} else {
	err = -ESRCH;
	}

	destroy_err:
	sock_put((struct sock *)msk);
	return err;
	}