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   1// SPDX-License-Identifier: GPL-2.0
   2/* Multipath TCP
   3 *
   4 * Copyright (c) 2020, Red Hat, Inc.
   5 */
   6
   7#define pr_fmt(fmt) "MPTCP: " fmt
   8
   9#include <linux/inet.h>
  10#include <linux/kernel.h>
  11#include <net/tcp.h>
  12#include <net/netns/generic.h>
  13#include <net/mptcp.h>
  14#include <net/genetlink.h>
  15#include <uapi/linux/mptcp.h>
  16
  17#include "protocol.h"
  18#include "mib.h"
  19
  20/* forward declaration */
  21static struct genl_family mptcp_genl_family;
  22
  23static int pm_nl_pernet_id;
  24
  25struct mptcp_pm_add_entry {
  26	struct list_head	list;
  27	struct mptcp_addr_info	addr;
  28	struct timer_list	add_timer;
  29	struct mptcp_sock	*sock;
  30	u8			retrans_times;
  31};
  32
  33struct pm_nl_pernet {
  34	/* protects pernet updates */
  35	spinlock_t		lock;
  36	struct list_head	local_addr_list;
  37	unsigned int		addrs;
  38	unsigned int		stale_loss_cnt;
  39	unsigned int		add_addr_signal_max;
  40	unsigned int		add_addr_accept_max;
  41	unsigned int		local_addr_max;
  42	unsigned int		subflows_max;
  43	unsigned int		next_id;
  44	DECLARE_BITMAP(id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
  45};
  46
  47#define MPTCP_PM_ADDR_MAX	8
  48#define ADD_ADDR_RETRANS_MAX	3
  49
  50static struct pm_nl_pernet *pm_nl_get_pernet(const struct net *net)
  51{
  52	return net_generic(net, pm_nl_pernet_id);
  53}
  54
  55static struct pm_nl_pernet *
  56pm_nl_get_pernet_from_msk(const struct mptcp_sock *msk)
  57{
  58	return pm_nl_get_pernet(sock_net((struct sock *)msk));
  59}
  60
  61bool mptcp_addresses_equal(const struct mptcp_addr_info *a,
  62			   const struct mptcp_addr_info *b, bool use_port)
  63{
  64	bool addr_equals = false;
  65
  66	if (a->family == b->family) {
  67		if (a->family == AF_INET)
  68			addr_equals = a->addr.s_addr == b->addr.s_addr;
  69#if IS_ENABLED(CONFIG_MPTCP_IPV6)
  70		else
  71			addr_equals = !ipv6_addr_cmp(&a->addr6, &b->addr6);
  72	} else if (a->family == AF_INET) {
  73		if (ipv6_addr_v4mapped(&b->addr6))
  74			addr_equals = a->addr.s_addr == b->addr6.s6_addr32[3];
  75	} else if (b->family == AF_INET) {
  76		if (ipv6_addr_v4mapped(&a->addr6))
  77			addr_equals = a->addr6.s6_addr32[3] == b->addr.s_addr;
  78#endif
  79	}
  80
  81	if (!addr_equals)
  82		return false;
  83	if (!use_port)
  84		return true;
  85
  86	return a->port == b->port;
  87}
  88
  89static void local_address(const struct sock_common *skc,
  90			  struct mptcp_addr_info *addr)
  91{
  92	addr->family = skc->skc_family;
  93	addr->port = htons(skc->skc_num);
  94	if (addr->family == AF_INET)
  95		addr->addr.s_addr = skc->skc_rcv_saddr;
  96#if IS_ENABLED(CONFIG_MPTCP_IPV6)
  97	else if (addr->family == AF_INET6)
  98		addr->addr6 = skc->skc_v6_rcv_saddr;
  99#endif
 100}
 101
 102static void remote_address(const struct sock_common *skc,
 103			   struct mptcp_addr_info *addr)
 104{
 105	addr->family = skc->skc_family;
 106	addr->port = skc->skc_dport;
 107	if (addr->family == AF_INET)
 108		addr->addr.s_addr = skc->skc_daddr;
 109#if IS_ENABLED(CONFIG_MPTCP_IPV6)
 110	else if (addr->family == AF_INET6)
 111		addr->addr6 = skc->skc_v6_daddr;
 112#endif
 113}
 114
 115static bool lookup_subflow_by_saddr(const struct list_head *list,
 116				    const struct mptcp_addr_info *saddr)
 117{
 118	struct mptcp_subflow_context *subflow;
 119	struct mptcp_addr_info cur;
 120	struct sock_common *skc;
 121
 122	list_for_each_entry(subflow, list, node) {
 123		skc = (struct sock_common *)mptcp_subflow_tcp_sock(subflow);
 124
 125		local_address(skc, &cur);
 126		if (mptcp_addresses_equal(&cur, saddr, saddr->port))
 127			return true;
 128	}
 129
 130	return false;
 131}
 132
 133static bool lookup_subflow_by_daddr(const struct list_head *list,
 134				    const struct mptcp_addr_info *daddr)
 135{
 136	struct mptcp_subflow_context *subflow;
 137	struct mptcp_addr_info cur;
 138	struct sock_common *skc;
 139
 140	list_for_each_entry(subflow, list, node) {
 141		skc = (struct sock_common *)mptcp_subflow_tcp_sock(subflow);
 142
 143		remote_address(skc, &cur);
 144		if (mptcp_addresses_equal(&cur, daddr, daddr->port))
 145			return true;
 146	}
 147
 148	return false;
 149}
 150
 151static struct mptcp_pm_addr_entry *
 152select_local_address(const struct pm_nl_pernet *pernet,
 153		     const struct mptcp_sock *msk)
 154{
 155	const struct sock *sk = (const struct sock *)msk;
 156	struct mptcp_pm_addr_entry *entry, *ret = NULL;
 157
 158	msk_owned_by_me(msk);
 159
 160	rcu_read_lock();
 161	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
 162		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW))
 163			continue;
 164
 165		if (!test_bit(entry->addr.id, msk->pm.id_avail_bitmap))
 166			continue;
 167
 168		if (entry->addr.family != sk->sk_family) {
 169#if IS_ENABLED(CONFIG_MPTCP_IPV6)
 170			if ((entry->addr.family == AF_INET &&
 171			     !ipv6_addr_v4mapped(&sk->sk_v6_daddr)) ||
 172			    (sk->sk_family == AF_INET &&
 173			     !ipv6_addr_v4mapped(&entry->addr.addr6)))
 174#endif
 175				continue;
 176		}
 177
 178		ret = entry;
 179		break;
 180	}
 181	rcu_read_unlock();
 182	return ret;
 183}
 184
 185static struct mptcp_pm_addr_entry *
 186select_signal_address(struct pm_nl_pernet *pernet, const struct mptcp_sock *msk)
 187{
 188	struct mptcp_pm_addr_entry *entry, *ret = NULL;
 189
 190	rcu_read_lock();
 191	/* do not keep any additional per socket state, just signal
 192	 * the address list in order.
 193	 * Note: removal from the local address list during the msk life-cycle
 194	 * can lead to additional addresses not being announced.
 195	 */
 196	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
 197		if (!test_bit(entry->addr.id, msk->pm.id_avail_bitmap))
 198			continue;
 199
 200		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL))
 201			continue;
 202
 203		ret = entry;
 204		break;
 205	}
 206	rcu_read_unlock();
 207	return ret;
 208}
 209
 210unsigned int mptcp_pm_get_add_addr_signal_max(const struct mptcp_sock *msk)
 211{
 212	const struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 213
 214	return READ_ONCE(pernet->add_addr_signal_max);
 215}
 216EXPORT_SYMBOL_GPL(mptcp_pm_get_add_addr_signal_max);
 217
 218unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk)
 219{
 220	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 221
 222	return READ_ONCE(pernet->add_addr_accept_max);
 223}
 224EXPORT_SYMBOL_GPL(mptcp_pm_get_add_addr_accept_max);
 225
 226unsigned int mptcp_pm_get_subflows_max(const struct mptcp_sock *msk)
 227{
 228	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 229
 230	return READ_ONCE(pernet->subflows_max);
 231}
 232EXPORT_SYMBOL_GPL(mptcp_pm_get_subflows_max);
 233
 234unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk)
 235{
 236	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 237
 238	return READ_ONCE(pernet->local_addr_max);
 239}
 240EXPORT_SYMBOL_GPL(mptcp_pm_get_local_addr_max);
 241
 242bool mptcp_pm_nl_check_work_pending(struct mptcp_sock *msk)
 243{
 244	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 245
 246	if (msk->pm.subflows == mptcp_pm_get_subflows_max(msk) ||
 247	    (find_next_and_bit(pernet->id_bitmap, msk->pm.id_avail_bitmap,
 248			       MPTCP_PM_MAX_ADDR_ID + 1, 0) == MPTCP_PM_MAX_ADDR_ID + 1)) {
 249		WRITE_ONCE(msk->pm.work_pending, false);
 250		return false;
 251	}
 252	return true;
 253}
 254
 255struct mptcp_pm_add_entry *
 256mptcp_lookup_anno_list_by_saddr(const struct mptcp_sock *msk,
 257				const struct mptcp_addr_info *addr)
 258{
 259	struct mptcp_pm_add_entry *entry;
 260
 261	lockdep_assert_held(&msk->pm.lock);
 262
 263	list_for_each_entry(entry, &msk->pm.anno_list, list) {
 264		if (mptcp_addresses_equal(&entry->addr, addr, true))
 265			return entry;
 266	}
 267
 268	return NULL;
 269}
 270
 271bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk)
 272{
 273	struct mptcp_pm_add_entry *entry;
 274	struct mptcp_addr_info saddr;
 275	bool ret = false;
 276
 277	local_address((struct sock_common *)sk, &saddr);
 278
 279	spin_lock_bh(&msk->pm.lock);
 280	list_for_each_entry(entry, &msk->pm.anno_list, list) {
 281		if (mptcp_addresses_equal(&entry->addr, &saddr, true)) {
 282			ret = true;
 283			goto out;
 284		}
 285	}
 286
 287out:
 288	spin_unlock_bh(&msk->pm.lock);
 289	return ret;
 290}
 291
 292static void mptcp_pm_add_timer(struct timer_list *timer)
 293{
 294	struct mptcp_pm_add_entry *entry = from_timer(entry, timer, add_timer);
 295	struct mptcp_sock *msk = entry->sock;
 296	struct sock *sk = (struct sock *)msk;
 297
 298	pr_debug("msk=%p", msk);
 299
 300	if (!msk)
 301		return;
 302
 303	if (inet_sk_state_load(sk) == TCP_CLOSE)
 304		return;
 305
 306	if (!entry->addr.id)
 307		return;
 308
 309	if (mptcp_pm_should_add_signal_addr(msk)) {
 310		sk_reset_timer(sk, timer, jiffies + TCP_RTO_MAX / 8);
 311		goto out;
 312	}
 313
 314	spin_lock_bh(&msk->pm.lock);
 315
 316	if (!mptcp_pm_should_add_signal_addr(msk)) {
 317		pr_debug("retransmit ADD_ADDR id=%d", entry->addr.id);
 318		mptcp_pm_announce_addr(msk, &entry->addr, false);
 319		mptcp_pm_add_addr_send_ack(msk);
 320		entry->retrans_times++;
 321	}
 322
 323	if (entry->retrans_times < ADD_ADDR_RETRANS_MAX)
 324		sk_reset_timer(sk, timer,
 325			       jiffies + mptcp_get_add_addr_timeout(sock_net(sk)));
 326
 327	spin_unlock_bh(&msk->pm.lock);
 328
 329	if (entry->retrans_times == ADD_ADDR_RETRANS_MAX)
 330		mptcp_pm_subflow_established(msk);
 331
 332out:
 333	__sock_put(sk);
 334}
 335
 336struct mptcp_pm_add_entry *
 337mptcp_pm_del_add_timer(struct mptcp_sock *msk,
 338		       const struct mptcp_addr_info *addr, bool check_id)
 339{
 340	struct mptcp_pm_add_entry *entry;
 341	struct sock *sk = (struct sock *)msk;
 342
 343	spin_lock_bh(&msk->pm.lock);
 344	entry = mptcp_lookup_anno_list_by_saddr(msk, addr);
 345	if (entry && (!check_id || entry->addr.id == addr->id))
 346		entry->retrans_times = ADD_ADDR_RETRANS_MAX;
 347	spin_unlock_bh(&msk->pm.lock);
 348
 349	if (entry && (!check_id || entry->addr.id == addr->id))
 350		sk_stop_timer_sync(sk, &entry->add_timer);
 351
 352	return entry;
 353}
 354
 355bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk,
 356			      const struct mptcp_pm_addr_entry *entry)
 357{
 358	struct mptcp_pm_add_entry *add_entry = NULL;
 359	struct sock *sk = (struct sock *)msk;
 360	struct net *net = sock_net(sk);
 361
 362	lockdep_assert_held(&msk->pm.lock);
 363
 364	add_entry = mptcp_lookup_anno_list_by_saddr(msk, &entry->addr);
 365
 366	if (add_entry) {
 367		if (mptcp_pm_is_kernel(msk))
 368			return false;
 369
 370		sk_reset_timer(sk, &add_entry->add_timer,
 371			       jiffies + mptcp_get_add_addr_timeout(net));
 372		return true;
 373	}
 374
 375	add_entry = kmalloc(sizeof(*add_entry), GFP_ATOMIC);
 376	if (!add_entry)
 377		return false;
 378
 379	list_add(&add_entry->list, &msk->pm.anno_list);
 380
 381	add_entry->addr = entry->addr;
 382	add_entry->sock = msk;
 383	add_entry->retrans_times = 0;
 384
 385	timer_setup(&add_entry->add_timer, mptcp_pm_add_timer, 0);
 386	sk_reset_timer(sk, &add_entry->add_timer,
 387		       jiffies + mptcp_get_add_addr_timeout(net));
 388
 389	return true;
 390}
 391
 392void mptcp_pm_free_anno_list(struct mptcp_sock *msk)
 393{
 394	struct mptcp_pm_add_entry *entry, *tmp;
 395	struct sock *sk = (struct sock *)msk;
 396	LIST_HEAD(free_list);
 397
 398	pr_debug("msk=%p", msk);
 399
 400	spin_lock_bh(&msk->pm.lock);
 401	list_splice_init(&msk->pm.anno_list, &free_list);
 402	spin_unlock_bh(&msk->pm.lock);
 403
 404	list_for_each_entry_safe(entry, tmp, &free_list, list) {
 405		sk_stop_timer_sync(sk, &entry->add_timer);
 406		kfree(entry);
 407	}
 408}
 409
 410static bool lookup_address_in_vec(const struct mptcp_addr_info *addrs, unsigned int nr,
 411				  const struct mptcp_addr_info *addr)
 412{
 413	int i;
 414
 415	for (i = 0; i < nr; i++) {
 416		if (addrs[i].id == addr->id)
 417			return true;
 418	}
 419
 420	return false;
 421}
 422
 423/* Fill all the remote addresses into the array addrs[],
 424 * and return the array size.
 425 */
 426static unsigned int fill_remote_addresses_vec(struct mptcp_sock *msk, bool fullmesh,
 427					      struct mptcp_addr_info *addrs)
 428{
 429	bool deny_id0 = READ_ONCE(msk->pm.remote_deny_join_id0);
 430	struct sock *sk = (struct sock *)msk, *ssk;
 431	struct mptcp_subflow_context *subflow;
 432	struct mptcp_addr_info remote = { 0 };
 433	unsigned int subflows_max;
 434	int i = 0;
 435
 436	subflows_max = mptcp_pm_get_subflows_max(msk);
 437	remote_address((struct sock_common *)sk, &remote);
 438
 439	/* Non-fullmesh endpoint, fill in the single entry
 440	 * corresponding to the primary MPC subflow remote address
 441	 */
 442	if (!fullmesh) {
 443		if (deny_id0)
 444			return 0;
 445
 446		msk->pm.subflows++;
 447		addrs[i++] = remote;
 448	} else {
 449		mptcp_for_each_subflow(msk, subflow) {
 450			ssk = mptcp_subflow_tcp_sock(subflow);
 451			remote_address((struct sock_common *)ssk, &addrs[i]);
 452			addrs[i].id = subflow->remote_id;
 453			if (deny_id0 && !addrs[i].id)
 454				continue;
 455
 456			if (!lookup_address_in_vec(addrs, i, &addrs[i]) &&
 457			    msk->pm.subflows < subflows_max) {
 458				msk->pm.subflows++;
 459				i++;
 460			}
 461		}
 462	}
 463
 464	return i;
 465}
 466
 467static void __mptcp_pm_send_ack(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
 468				bool prio, bool backup)
 469{
 470	struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 471	bool slow;
 472
 473	pr_debug("send ack for %s",
 474		 prio ? "mp_prio" : (mptcp_pm_should_add_signal(msk) ? "add_addr" : "rm_addr"));
 475
 476	slow = lock_sock_fast(ssk);
 477	if (prio) {
 478		if (subflow->backup != backup)
 479			msk->last_snd = NULL;
 480
 481		subflow->send_mp_prio = 1;
 482		subflow->backup = backup;
 483		subflow->request_bkup = backup;
 484	}
 485
 486	__mptcp_subflow_send_ack(ssk);
 487	unlock_sock_fast(ssk, slow);
 488}
 489
 490static void mptcp_pm_send_ack(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
 491			      bool prio, bool backup)
 492{
 493	spin_unlock_bh(&msk->pm.lock);
 494	__mptcp_pm_send_ack(msk, subflow, prio, backup);
 495	spin_lock_bh(&msk->pm.lock);
 496}
 497
 498static struct mptcp_pm_addr_entry *
 499__lookup_addr_by_id(struct pm_nl_pernet *pernet, unsigned int id)
 500{
 501	struct mptcp_pm_addr_entry *entry;
 502
 503	list_for_each_entry(entry, &pernet->local_addr_list, list) {
 504		if (entry->addr.id == id)
 505			return entry;
 506	}
 507	return NULL;
 508}
 509
 510static struct mptcp_pm_addr_entry *
 511__lookup_addr(struct pm_nl_pernet *pernet, const struct mptcp_addr_info *info,
 512	      bool lookup_by_id)
 513{
 514	struct mptcp_pm_addr_entry *entry;
 515
 516	list_for_each_entry(entry, &pernet->local_addr_list, list) {
 517		if ((!lookup_by_id &&
 518		     mptcp_addresses_equal(&entry->addr, info, entry->addr.port)) ||
 519		    (lookup_by_id && entry->addr.id == info->id))
 520			return entry;
 521	}
 522	return NULL;
 523}
 524
 525static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 526{
 527	struct sock *sk = (struct sock *)msk;
 528	struct mptcp_pm_addr_entry *local;
 529	unsigned int add_addr_signal_max;
 530	unsigned int local_addr_max;
 531	struct pm_nl_pernet *pernet;
 532	unsigned int subflows_max;
 533
 534	pernet = pm_nl_get_pernet(sock_net(sk));
 535
 536	add_addr_signal_max = mptcp_pm_get_add_addr_signal_max(msk);
 537	local_addr_max = mptcp_pm_get_local_addr_max(msk);
 538	subflows_max = mptcp_pm_get_subflows_max(msk);
 539
 540	/* do lazy endpoint usage accounting for the MPC subflows */
 541	if (unlikely(!(msk->pm.status & BIT(MPTCP_PM_MPC_ENDPOINT_ACCOUNTED))) && msk->first) {
 542		struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(msk->first);
 543		struct mptcp_pm_addr_entry *entry;
 544		struct mptcp_addr_info mpc_addr;
 545		bool backup = false;
 546
 547		local_address((struct sock_common *)msk->first, &mpc_addr);
 548		rcu_read_lock();
 549		entry = __lookup_addr(pernet, &mpc_addr, false);
 550		if (entry) {
 551			__clear_bit(entry->addr.id, msk->pm.id_avail_bitmap);
 552			msk->mpc_endpoint_id = entry->addr.id;
 553			backup = !!(entry->flags & MPTCP_PM_ADDR_FLAG_BACKUP);
 554		}
 555		rcu_read_unlock();
 556
 557		if (backup)
 558			mptcp_pm_send_ack(msk, subflow, true, backup);
 559
 560		msk->pm.status |= BIT(MPTCP_PM_MPC_ENDPOINT_ACCOUNTED);
 561	}
 562
 563	pr_debug("local %d:%d signal %d:%d subflows %d:%d\n",
 564		 msk->pm.local_addr_used, local_addr_max,
 565		 msk->pm.add_addr_signaled, add_addr_signal_max,
 566		 msk->pm.subflows, subflows_max);
 567
 568	/* check first for announce */
 569	if (msk->pm.add_addr_signaled < add_addr_signal_max) {
 570		local = select_signal_address(pernet, msk);
 571
 572		/* due to racing events on both ends we can reach here while
 573		 * previous add address is still running: if we invoke now
 574		 * mptcp_pm_announce_addr(), that will fail and the
 575		 * corresponding id will be marked as used.
 576		 * Instead let the PM machinery reschedule us when the
 577		 * current address announce will be completed.
 578		 */
 579		if (msk->pm.addr_signal & BIT(MPTCP_ADD_ADDR_SIGNAL))
 580			return;
 581
 582		if (local) {
 583			if (mptcp_pm_alloc_anno_list(msk, local)) {
 584				__clear_bit(local->addr.id, msk->pm.id_avail_bitmap);
 585				msk->pm.add_addr_signaled++;
 586				mptcp_pm_announce_addr(msk, &local->addr, false);
 587				mptcp_pm_nl_addr_send_ack(msk);
 588			}
 589		}
 590	}
 591
 592	/* check if should create a new subflow */
 593	while (msk->pm.local_addr_used < local_addr_max &&
 594	       msk->pm.subflows < subflows_max) {
 595		struct mptcp_addr_info addrs[MPTCP_PM_ADDR_MAX];
 596		bool fullmesh;
 597		int i, nr;
 598
 599		local = select_local_address(pernet, msk);
 600		if (!local)
 601			break;
 602
 603		fullmesh = !!(local->flags & MPTCP_PM_ADDR_FLAG_FULLMESH);
 604
 605		msk->pm.local_addr_used++;
 606		nr = fill_remote_addresses_vec(msk, fullmesh, addrs);
 607		if (nr)
 608			__clear_bit(local->addr.id, msk->pm.id_avail_bitmap);
 609		spin_unlock_bh(&msk->pm.lock);
 610		for (i = 0; i < nr; i++)
 611			__mptcp_subflow_connect(sk, &local->addr, &addrs[i]);
 612		spin_lock_bh(&msk->pm.lock);
 613	}
 614	mptcp_pm_nl_check_work_pending(msk);
 615}
 616
 617static void mptcp_pm_nl_fully_established(struct mptcp_sock *msk)
 618{
 619	mptcp_pm_create_subflow_or_signal_addr(msk);
 620}
 621
 622static void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk)
 623{
 624	mptcp_pm_create_subflow_or_signal_addr(msk);
 625}
 626
 627/* Fill all the local addresses into the array addrs[],
 628 * and return the array size.
 629 */
 630static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
 631					     struct mptcp_addr_info *addrs)
 632{
 633	struct sock *sk = (struct sock *)msk;
 634	struct mptcp_pm_addr_entry *entry;
 635	struct mptcp_addr_info local;
 636	struct pm_nl_pernet *pernet;
 637	unsigned int subflows_max;
 638	int i = 0;
 639
 640	pernet = pm_nl_get_pernet_from_msk(msk);
 641	subflows_max = mptcp_pm_get_subflows_max(msk);
 642
 643	rcu_read_lock();
 644	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
 645		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_FULLMESH))
 646			continue;
 647
 648		if (entry->addr.family != sk->sk_family) {
 649#if IS_ENABLED(CONFIG_MPTCP_IPV6)
 650			if ((entry->addr.family == AF_INET &&
 651			     !ipv6_addr_v4mapped(&sk->sk_v6_daddr)) ||
 652			    (sk->sk_family == AF_INET &&
 653			     !ipv6_addr_v4mapped(&entry->addr.addr6)))
 654#endif
 655				continue;
 656		}
 657
 658		if (msk->pm.subflows < subflows_max) {
 659			msk->pm.subflows++;
 660			addrs[i++] = entry->addr;
 661		}
 662	}
 663	rcu_read_unlock();
 664
 665	/* If the array is empty, fill in the single
 666	 * 'IPADDRANY' local address
 667	 */
 668	if (!i) {
 669		memset(&local, 0, sizeof(local));
 670		local.family = msk->pm.remote.family;
 671
 672		msk->pm.subflows++;
 673		addrs[i++] = local;
 674	}
 675
 676	return i;
 677}
 678
 679static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 680{
 681	struct mptcp_addr_info addrs[MPTCP_PM_ADDR_MAX];
 682	struct sock *sk = (struct sock *)msk;
 683	unsigned int add_addr_accept_max;
 684	struct mptcp_addr_info remote;
 685	unsigned int subflows_max;
 686	int i, nr;
 687
 688	add_addr_accept_max = mptcp_pm_get_add_addr_accept_max(msk);
 689	subflows_max = mptcp_pm_get_subflows_max(msk);
 690
 691	pr_debug("accepted %d:%d remote family %d",
 692		 msk->pm.add_addr_accepted, add_addr_accept_max,
 693		 msk->pm.remote.family);
 694
 695	remote = msk->pm.remote;
 696	mptcp_pm_announce_addr(msk, &remote, true);
 697	mptcp_pm_nl_addr_send_ack(msk);
 698
 699	if (lookup_subflow_by_daddr(&msk->conn_list, &remote))
 700		return;
 701
 702	/* pick id 0 port, if none is provided the remote address */
 703	if (!remote.port)
 704		remote.port = sk->sk_dport;
 705
 706	/* connect to the specified remote address, using whatever
 707	 * local address the routing configuration will pick.
 708	 */
 709	nr = fill_local_addresses_vec(msk, addrs);
 710
 711	msk->pm.add_addr_accepted++;
 712	if (msk->pm.add_addr_accepted >= add_addr_accept_max ||
 713	    msk->pm.subflows >= subflows_max)
 714		WRITE_ONCE(msk->pm.accept_addr, false);
 715
 716	spin_unlock_bh(&msk->pm.lock);
 717	for (i = 0; i < nr; i++)
 718		__mptcp_subflow_connect(sk, &addrs[i], &remote);
 719	spin_lock_bh(&msk->pm.lock);
 720}
 721
 722void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk)
 723{
 724	struct mptcp_subflow_context *subflow;
 725
 726	msk_owned_by_me(msk);
 727	lockdep_assert_held(&msk->pm.lock);
 728
 729	if (!mptcp_pm_should_add_signal(msk) &&
 730	    !mptcp_pm_should_rm_signal(msk))
 731		return;
 732
 733	subflow = list_first_entry_or_null(&msk->conn_list, typeof(*subflow), node);
 734	if (subflow)
 735		mptcp_pm_send_ack(msk, subflow, false, false);
 736}
 737
 738int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
 739				 struct mptcp_addr_info *addr,
 740				 struct mptcp_addr_info *rem,
 741				 u8 bkup)
 742{
 743	struct mptcp_subflow_context *subflow;
 744
 745	pr_debug("bkup=%d", bkup);
 746
 747	mptcp_for_each_subflow(msk, subflow) {
 748		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 749		struct mptcp_addr_info local, remote;
 750
 751		local_address((struct sock_common *)ssk, &local);
 752		if (!mptcp_addresses_equal(&local, addr, addr->port))
 753			continue;
 754
 755		if (rem && rem->family != AF_UNSPEC) {
 756			remote_address((struct sock_common *)ssk, &remote);
 757			if (!mptcp_addresses_equal(&remote, rem, rem->port))
 758				continue;
 759		}
 760
 761		__mptcp_pm_send_ack(msk, subflow, true, bkup);
 762		return 0;
 763	}
 764
 765	return -EINVAL;
 766}
 767
 768static bool mptcp_local_id_match(const struct mptcp_sock *msk, u8 local_id, u8 id)
 769{
 770	return local_id == id || (!local_id && msk->mpc_endpoint_id == id);
 771}
 772
 773static void mptcp_pm_nl_rm_addr_or_subflow(struct mptcp_sock *msk,
 774					   const struct mptcp_rm_list *rm_list,
 775					   enum linux_mptcp_mib_field rm_type)
 776{
 777	struct mptcp_subflow_context *subflow, *tmp;
 778	struct sock *sk = (struct sock *)msk;
 779	u8 i;
 780
 781	pr_debug("%s rm_list_nr %d",
 782		 rm_type == MPTCP_MIB_RMADDR ? "address" : "subflow", rm_list->nr);
 783
 784	msk_owned_by_me(msk);
 785
 786	if (sk->sk_state == TCP_LISTEN)
 787		return;
 788
 789	if (!rm_list->nr)
 790		return;
 791
 792	if (list_empty(&msk->conn_list))
 793		return;
 794
 795	for (i = 0; i < rm_list->nr; i++) {
 796		u8 rm_id = rm_list->ids[i];
 797		bool removed = false;
 798
 799		mptcp_for_each_subflow_safe(msk, subflow, tmp) {
 800			struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 801			int how = RCV_SHUTDOWN | SEND_SHUTDOWN;
 802			u8 id = subflow->local_id;
 803
 804			if (rm_type == MPTCP_MIB_RMADDR && subflow->remote_id != rm_id)
 805				continue;
 806			if (rm_type == MPTCP_MIB_RMSUBFLOW && !mptcp_local_id_match(msk, id, rm_id))
 807				continue;
 808
 809			pr_debug(" -> %s rm_list_ids[%d]=%u local_id=%u remote_id=%u mpc_id=%u",
 810				 rm_type == MPTCP_MIB_RMADDR ? "address" : "subflow",
 811				 i, rm_id, subflow->local_id, subflow->remote_id,
 812				 msk->mpc_endpoint_id);
 813			spin_unlock_bh(&msk->pm.lock);
 814			mptcp_subflow_shutdown(sk, ssk, how);
 815
 816			/* the following takes care of updating the subflows counter */
 817			mptcp_close_ssk(sk, ssk, subflow);
 818			spin_lock_bh(&msk->pm.lock);
 819
 820			removed = true;
 821			__MPTCP_INC_STATS(sock_net(sk), rm_type);
 822		}
 823		if (rm_type == MPTCP_MIB_RMSUBFLOW)
 824			__set_bit(rm_id ? rm_id : msk->mpc_endpoint_id, msk->pm.id_avail_bitmap);
 825		if (!removed)
 826			continue;
 827
 828		if (!mptcp_pm_is_kernel(msk))
 829			continue;
 830
 831		if (rm_type == MPTCP_MIB_RMADDR) {
 832			msk->pm.add_addr_accepted--;
 833			WRITE_ONCE(msk->pm.accept_addr, true);
 834		} else if (rm_type == MPTCP_MIB_RMSUBFLOW) {
 835			msk->pm.local_addr_used--;
 836		}
 837	}
 838}
 839
 840static void mptcp_pm_nl_rm_addr_received(struct mptcp_sock *msk)
 841{
 842	mptcp_pm_nl_rm_addr_or_subflow(msk, &msk->pm.rm_list_rx, MPTCP_MIB_RMADDR);
 843}
 844
 845void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk,
 846				     const struct mptcp_rm_list *rm_list)
 847{
 848	mptcp_pm_nl_rm_addr_or_subflow(msk, rm_list, MPTCP_MIB_RMSUBFLOW);
 849}
 850
 851void mptcp_pm_nl_work(struct mptcp_sock *msk)
 852{
 853	struct mptcp_pm_data *pm = &msk->pm;
 854
 855	msk_owned_by_me(msk);
 856
 857	if (!(pm->status & MPTCP_PM_WORK_MASK))
 858		return;
 859
 860	spin_lock_bh(&msk->pm.lock);
 861
 862	pr_debug("msk=%p status=%x", msk, pm->status);
 863	if (pm->status & BIT(MPTCP_PM_ADD_ADDR_RECEIVED)) {
 864		pm->status &= ~BIT(MPTCP_PM_ADD_ADDR_RECEIVED);
 865		mptcp_pm_nl_add_addr_received(msk);
 866	}
 867	if (pm->status & BIT(MPTCP_PM_ADD_ADDR_SEND_ACK)) {
 868		pm->status &= ~BIT(MPTCP_PM_ADD_ADDR_SEND_ACK);
 869		mptcp_pm_nl_addr_send_ack(msk);
 870	}
 871	if (pm->status & BIT(MPTCP_PM_RM_ADDR_RECEIVED)) {
 872		pm->status &= ~BIT(MPTCP_PM_RM_ADDR_RECEIVED);
 873		mptcp_pm_nl_rm_addr_received(msk);
 874	}
 875	if (pm->status & BIT(MPTCP_PM_ESTABLISHED)) {
 876		pm->status &= ~BIT(MPTCP_PM_ESTABLISHED);
 877		mptcp_pm_nl_fully_established(msk);
 878	}
 879	if (pm->status & BIT(MPTCP_PM_SUBFLOW_ESTABLISHED)) {
 880		pm->status &= ~BIT(MPTCP_PM_SUBFLOW_ESTABLISHED);
 881		mptcp_pm_nl_subflow_established(msk);
 882	}
 883
 884	spin_unlock_bh(&msk->pm.lock);
 885}
 886
 887static bool address_use_port(struct mptcp_pm_addr_entry *entry)
 888{
 889	return (entry->flags &
 890		(MPTCP_PM_ADDR_FLAG_SIGNAL | MPTCP_PM_ADDR_FLAG_SUBFLOW)) ==
 891		MPTCP_PM_ADDR_FLAG_SIGNAL;
 892}
 893
 894/* caller must ensure the RCU grace period is already elapsed */
 895static void __mptcp_pm_release_addr_entry(struct mptcp_pm_addr_entry *entry)
 896{
 897	if (entry->lsk)
 898		sock_release(entry->lsk);
 899	kfree(entry);
 900}
 901
 902static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
 903					     struct mptcp_pm_addr_entry *entry)
 904{
 905	struct mptcp_pm_addr_entry *cur, *del_entry = NULL;
 906	unsigned int addr_max;
 907	int ret = -EINVAL;
 908
 909	spin_lock_bh(&pernet->lock);
 910	/* to keep the code simple, don't do IDR-like allocation for address ID,
 911	 * just bail when we exceed limits
 912	 */
 913	if (pernet->next_id == MPTCP_PM_MAX_ADDR_ID)
 914		pernet->next_id = 1;
 915	if (pernet->addrs >= MPTCP_PM_ADDR_MAX) {
 916		ret = -ERANGE;
 917		goto out;
 918	}
 919	if (test_bit(entry->addr.id, pernet->id_bitmap)) {
 920		ret = -EBUSY;
 921		goto out;
 922	}
 923
 924	/* do not insert duplicate address, differentiate on port only
 925	 * singled addresses
 926	 */
 927	if (!address_use_port(entry))
 928		entry->addr.port = 0;
 929	list_for_each_entry(cur, &pernet->local_addr_list, list) {
 930		if (mptcp_addresses_equal(&cur->addr, &entry->addr,
 931					  cur->addr.port || entry->addr.port)) {
 932			/* allow replacing the exiting endpoint only if such
 933			 * endpoint is an implicit one and the user-space
 934			 * did not provide an endpoint id
 935			 */
 936			if (!(cur->flags & MPTCP_PM_ADDR_FLAG_IMPLICIT)) {
 937				ret = -EEXIST;
 938				goto out;
 939			}
 940			if (entry->addr.id)
 941				goto out;
 942
 943			pernet->addrs--;
 944			entry->addr.id = cur->addr.id;
 945			list_del_rcu(&cur->list);
 946			del_entry = cur;
 947			break;
 948		}
 949	}
 950
 951	if (!entry->addr.id) {
 952find_next:
 953		entry->addr.id = find_next_zero_bit(pernet->id_bitmap,
 954						    MPTCP_PM_MAX_ADDR_ID + 1,
 955						    pernet->next_id);
 956		if (!entry->addr.id && pernet->next_id != 1) {
 957			pernet->next_id = 1;
 958			goto find_next;
 959		}
 960	}
 961
 962	if (!entry->addr.id)
 963		goto out;
 964
 965	__set_bit(entry->addr.id, pernet->id_bitmap);
 966	if (entry->addr.id > pernet->next_id)
 967		pernet->next_id = entry->addr.id;
 968
 969	if (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL) {
 970		addr_max = pernet->add_addr_signal_max;
 971		WRITE_ONCE(pernet->add_addr_signal_max, addr_max + 1);
 972	}
 973	if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) {
 974		addr_max = pernet->local_addr_max;
 975		WRITE_ONCE(pernet->local_addr_max, addr_max + 1);
 976	}
 977
 978	pernet->addrs++;
 979	if (!entry->addr.port)
 980		list_add_tail_rcu(&entry->list, &pernet->local_addr_list);
 981	else
 982		list_add_rcu(&entry->list, &pernet->local_addr_list);
 983	ret = entry->addr.id;
 984
 985out:
 986	spin_unlock_bh(&pernet->lock);
 987
 988	/* just replaced an existing entry, free it */
 989	if (del_entry) {
 990		synchronize_rcu();
 991		__mptcp_pm_release_addr_entry(del_entry);
 992	}
 993	return ret;
 994}
 995
 996static int mptcp_pm_nl_create_listen_socket(struct sock *sk,
 997					    struct mptcp_pm_addr_entry *entry)
 998{
 999	int addrlen = sizeof(struct sockaddr_in);
1000	struct sockaddr_storage addr;
1001	struct socket *ssock;
1002	struct sock *newsk;
1003	int backlog = 1024;
1004	int err;
1005
1006	err = sock_create_kern(sock_net(sk), entry->addr.family,
1007			       SOCK_STREAM, IPPROTO_MPTCP, &entry->lsk);
1008	if (err)
1009		return err;
1010
1011	newsk = entry->lsk->sk;
1012	if (!newsk)
1013		return -EINVAL;
1014
1015	lock_sock(newsk);
1016	ssock = __mptcp_nmpc_socket(mptcp_sk(newsk));
1017	release_sock(newsk);
1018	if (!ssock)
1019		return -EINVAL;
1020
1021	mptcp_info2sockaddr(&entry->addr, &addr, entry->addr.family);
1022#if IS_ENABLED(CONFIG_MPTCP_IPV6)
1023	if (entry->addr.family == AF_INET6)
1024		addrlen = sizeof(struct sockaddr_in6);
1025#endif
1026	err = kernel_bind(ssock, (struct sockaddr *)&addr, addrlen);
1027	if (err)
1028		return err;
1029
1030	err = kernel_listen(ssock, backlog);
1031	if (err)
1032		return err;
1033
1034	mptcp_event_pm_listener(ssock->sk, MPTCP_EVENT_LISTENER_CREATED);
1035
1036	return 0;
1037}
1038
1039int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
1040{
1041	struct mptcp_pm_addr_entry *entry;
1042	struct mptcp_addr_info skc_local;
1043	struct mptcp_addr_info msk_local;
1044	struct pm_nl_pernet *pernet;
1045	int ret = -1;
1046
1047	if (WARN_ON_ONCE(!msk))
1048		return -1;
1049
1050	/* The 0 ID mapping is defined by the first subflow, copied into the msk
1051	 * addr
1052	 */
1053	local_address((struct sock_common *)msk, &msk_local);
1054	local_address((struct sock_common *)skc, &skc_local);
1055	if (mptcp_addresses_equal(&msk_local, &skc_local, false))
1056		return 0;
1057
1058	if (mptcp_pm_is_userspace(msk))
1059		return mptcp_userspace_pm_get_local_id(msk, &skc_local);
1060
1061	pernet = pm_nl_get_pernet_from_msk(msk);
1062
1063	rcu_read_lock();
1064	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
1065		if (mptcp_addresses_equal(&entry->addr, &skc_local, entry->addr.port)) {
1066			ret = entry->addr.id;
1067			break;
1068		}
1069	}
1070	rcu_read_unlock();
1071	if (ret >= 0)
1072		return ret;
1073
1074	/* address not found, add to local list */
1075	entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
1076	if (!entry)
1077		return -ENOMEM;
1078
1079	entry->addr = skc_local;
1080	entry->addr.id = 0;
1081	entry->addr.port = 0;
1082	entry->ifindex = 0;
1083	entry->flags = MPTCP_PM_ADDR_FLAG_IMPLICIT;
1084	entry->lsk = NULL;
1085	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);
1086	if (ret < 0)
1087		kfree(entry);
1088
1089	return ret;
1090}
1091
1092#define MPTCP_PM_CMD_GRP_OFFSET       0
1093#define MPTCP_PM_EV_GRP_OFFSET        1
1094
1095static const struct genl_multicast_group mptcp_pm_mcgrps[] = {
1096	[MPTCP_PM_CMD_GRP_OFFSET]	= { .name = MPTCP_PM_CMD_GRP_NAME, },
1097	[MPTCP_PM_EV_GRP_OFFSET]        = { .name = MPTCP_PM_EV_GRP_NAME,
1098					    .flags = GENL_UNS_ADMIN_PERM,
1099					  },
1100};
1101
1102static const struct nla_policy
1103mptcp_pm_addr_policy[MPTCP_PM_ADDR_ATTR_MAX + 1] = {
1104	[MPTCP_PM_ADDR_ATTR_FAMILY]	= { .type	= NLA_U16,	},
1105	[MPTCP_PM_ADDR_ATTR_ID]		= { .type	= NLA_U8,	},
1106	[MPTCP_PM_ADDR_ATTR_ADDR4]	= { .type	= NLA_U32,	},
1107	[MPTCP_PM_ADDR_ATTR_ADDR6]	=
1108		NLA_POLICY_EXACT_LEN(sizeof(struct in6_addr)),
1109	[MPTCP_PM_ADDR_ATTR_PORT]	= { .type	= NLA_U16	},
1110	[MPTCP_PM_ADDR_ATTR_FLAGS]	= { .type	= NLA_U32	},
1111	[MPTCP_PM_ADDR_ATTR_IF_IDX]     = { .type	= NLA_S32	},
1112};
1113
1114static const struct nla_policy mptcp_pm_policy[MPTCP_PM_ATTR_MAX + 1] = {
1115	[MPTCP_PM_ATTR_ADDR]		=
1116					NLA_POLICY_NESTED(mptcp_pm_addr_policy),
1117	[MPTCP_PM_ATTR_RCV_ADD_ADDRS]	= { .type	= NLA_U32,	},
1118	[MPTCP_PM_ATTR_SUBFLOWS]	= { .type	= NLA_U32,	},
1119	[MPTCP_PM_ATTR_TOKEN]		= { .type	= NLA_U32,	},
1120	[MPTCP_PM_ATTR_LOC_ID]		= { .type	= NLA_U8,	},
1121	[MPTCP_PM_ATTR_ADDR_REMOTE]	=
1122					NLA_POLICY_NESTED(mptcp_pm_addr_policy),
1123};
1124
1125void mptcp_pm_nl_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk)
1126{
1127	struct mptcp_subflow_context *iter, *subflow = mptcp_subflow_ctx(ssk);
1128	struct sock *sk = (struct sock *)msk;
1129	unsigned int active_max_loss_cnt;
1130	struct net *net = sock_net(sk);
1131	unsigned int stale_loss_cnt;
1132	bool slow;
1133
1134	stale_loss_cnt = mptcp_stale_loss_cnt(net);
1135	if (subflow->stale || !stale_loss_cnt || subflow->stale_count <= stale_loss_cnt)
1136		return;
1137
1138	/* look for another available subflow not in loss state */
1139	active_max_loss_cnt = max_t(int, stale_loss_cnt - 1, 1);
1140	mptcp_for_each_subflow(msk, iter) {
1141		if (iter != subflow && mptcp_subflow_active(iter) &&
1142		    iter->stale_count < active_max_loss_cnt) {
1143			/* we have some alternatives, try to mark this subflow as idle ...*/
1144			slow = lock_sock_fast(ssk);
1145			if (!tcp_rtx_and_write_queues_empty(ssk)) {
1146				subflow->stale = 1;
1147				__mptcp_retransmit_pending_data(sk);
1148				MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_SUBFLOWSTALE);
1149			}
1150			unlock_sock_fast(ssk, slow);
1151
1152			/* always try to push the pending data regardless of re-injections:
1153			 * we can possibly use backup subflows now, and subflow selection
1154			 * is cheap under the msk socket lock
1155			 */
1156			__mptcp_push_pending(sk, 0);
1157			return;
1158		}
1159	}
1160}
1161
1162static int mptcp_pm_family_to_addr(int family)
1163{
1164#if IS_ENABLED(CONFIG_MPTCP_IPV6)
1165	if (family == AF_INET6)
1166		return MPTCP_PM_ADDR_ATTR_ADDR6;
1167#endif
1168	return MPTCP_PM_ADDR_ATTR_ADDR4;
1169}
1170
1171static int mptcp_pm_parse_pm_addr_attr(struct nlattr *tb[],
1172				       const struct nlattr *attr,
1173				       struct genl_info *info,
1174				       struct mptcp_addr_info *addr,
1175				       bool require_family)
1176{
1177	int err, addr_addr;
1178
1179	if (!attr) {
1180		GENL_SET_ERR_MSG(info, "missing address info");
1181		return -EINVAL;
1182	}
1183
1184	/* no validation needed - was already done via nested policy */
1185	err = nla_parse_nested_deprecated(tb, MPTCP_PM_ADDR_ATTR_MAX, attr,
1186					  mptcp_pm_addr_policy, info->extack);
1187	if (err)
1188		return err;
1189
1190	if (tb[MPTCP_PM_ADDR_ATTR_ID])
1191		addr->id = nla_get_u8(tb[MPTCP_PM_ADDR_ATTR_ID]);
1192
1193	if (!tb[MPTCP_PM_ADDR_ATTR_FAMILY]) {
1194		if (!require_family)
1195			return 0;
1196
1197		NL_SET_ERR_MSG_ATTR(info->extack, attr,
1198				    "missing family");
1199		return -EINVAL;
1200	}
1201
1202	addr->family = nla_get_u16(tb[MPTCP_PM_ADDR_ATTR_FAMILY]);
1203	if (addr->family != AF_INET
1204#if IS_ENABLED(CONFIG_MPTCP_IPV6)
1205	    && addr->family != AF_INET6
1206#endif
1207	    ) {
1208		NL_SET_ERR_MSG_ATTR(info->extack, attr,
1209				    "unknown address family");
1210		return -EINVAL;
1211	}
1212	addr_addr = mptcp_pm_family_to_addr(addr->family);
1213	if (!tb[addr_addr]) {
1214		NL_SET_ERR_MSG_ATTR(info->extack, attr,
1215				    "missing address data");
1216		return -EINVAL;
1217	}
1218
1219#if IS_ENABLED(CONFIG_MPTCP_IPV6)
1220	if (addr->family == AF_INET6)
1221		addr->addr6 = nla_get_in6_addr(tb[addr_addr]);
1222	else
1223#endif
1224		addr->addr.s_addr = nla_get_in_addr(tb[addr_addr]);
1225
1226	if (tb[MPTCP_PM_ADDR_ATTR_PORT])
1227		addr->port = htons(nla_get_u16(tb[MPTCP_PM_ADDR_ATTR_PORT]));
1228
1229	return 0;
1230}
1231
1232int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info,
1233			struct mptcp_addr_info *addr)
1234{
1235	struct nlattr *tb[MPTCP_PM_ADDR_ATTR_MAX + 1];
1236
1237	memset(addr, 0, sizeof(*addr));
1238
1239	return mptcp_pm_parse_pm_addr_attr(tb, attr, info, addr, true);
1240}
1241
1242int mptcp_pm_parse_entry(struct nlattr *attr, struct genl_info *info,
1243			 bool require_family,
1244			 struct mptcp_pm_addr_entry *entry)
1245{
1246	struct nlattr *tb[MPTCP_PM_ADDR_ATTR_MAX + 1];
1247	int err;
1248
1249	memset(entry, 0, sizeof(*entry));
1250
1251	err = mptcp_pm_parse_pm_addr_attr(tb, attr, info, &entry->addr, require_family);
1252	if (err)
1253		return err;
1254
1255	if (tb[MPTCP_PM_ADDR_ATTR_IF_IDX]) {
1256		u32 val = nla_get_s32(tb[MPTCP_PM_ADDR_ATTR_IF_IDX]);
1257
1258		entry->ifindex = val;
1259	}
1260
1261	if (tb[MPTCP_PM_ADDR_ATTR_FLAGS])
1262		entry->flags = nla_get_u32(tb[MPTCP_PM_ADDR_ATTR_FLAGS]);
1263
1264	if (tb[MPTCP_PM_ADDR_ATTR_PORT])
1265		entry->addr.port = htons(nla_get_u16(tb[MPTCP_PM_ADDR_ATTR_PORT]));
1266
1267	return 0;
1268}
1269
1270static struct pm_nl_pernet *genl_info_pm_nl(struct genl_info *info)
1271{
1272	return pm_nl_get_pernet(genl_info_net(info));
1273}
1274
1275static int mptcp_nl_add_subflow_or_signal_addr(struct net *net)
1276{
1277	struct mptcp_sock *msk;
1278	long s_slot = 0, s_num = 0;
1279
1280	while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
1281		struct sock *sk = (struct sock *)msk;
1282
1283		if (!READ_ONCE(msk->fully_established) ||
1284		    mptcp_pm_is_userspace(msk))
1285			goto next;
1286
1287		lock_sock(sk);
1288		spin_lock_bh(&msk->pm.lock);
1289		mptcp_pm_create_subflow_or_signal_addr(msk);
1290		spin_unlock_bh(&msk->pm.lock);
1291		release_sock(sk);
1292
1293next:
1294		sock_put(sk);
1295		cond_resched();
1296	}
1297
1298	return 0;
1299}
1300
1301static int mptcp_nl_cmd_add_addr(struct sk_buff *skb, struct genl_info *info)
1302{
1303	struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
1304	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1305	struct mptcp_pm_addr_entry addr, *entry;
1306	int ret;
1307
1308	ret = mptcp_pm_parse_entry(attr, info, true, &addr);
1309	if (ret < 0)
1310		return ret;
1311
1312	if (addr.addr.port && !(addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL)) {
1313		GENL_SET_ERR_MSG(info, "flags must have signal when using port");
1314		return -EINVAL;
1315	}
1316
1317	if (addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL &&
1318	    addr.flags & MPTCP_PM_ADDR_FLAG_FULLMESH) {
1319		GENL_SET_ERR_MSG(info, "flags mustn't have both signal and fullmesh");
1320		return -EINVAL;
1321	}
1322
1323	if (addr.flags & MPTCP_PM_ADDR_FLAG_IMPLICIT) {
1324		GENL_SET_ERR_MSG(info, "can't create IMPLICIT endpoint");
1325		return -EINVAL;
1326	}
1327
1328	entry = kzalloc(sizeof(*entry), GFP_KERNEL_ACCOUNT);
1329	if (!entry) {
1330		GENL_SET_ERR_MSG(info, "can't allocate addr");
1331		return -ENOMEM;
1332	}
1333
1334	*entry = addr;
1335	if (entry->addr.port) {
1336		ret = mptcp_pm_nl_create_listen_socket(skb->sk, entry);
1337		if (ret) {
1338			GENL_SET_ERR_MSG_FMT(info, "create listen socket error: %d", ret);
1339			goto out_free;
1340		}
1341	}
1342	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);
1343	if (ret < 0) {
1344		GENL_SET_ERR_MSG_FMT(info, "too many addresses or duplicate one: %d", ret);
1345		goto out_free;
1346	}
1347
1348	mptcp_nl_add_subflow_or_signal_addr(sock_net(skb->sk));
1349	return 0;
1350
1351out_free:
1352	__mptcp_pm_release_addr_entry(entry);
1353	return ret;
1354}
1355
1356int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id,
1357					 u8 *flags, int *ifindex)
1358{
1359	struct mptcp_pm_addr_entry *entry;
1360	struct sock *sk = (struct sock *)msk;
1361	struct net *net = sock_net(sk);
1362
1363	*flags = 0;
1364	*ifindex = 0;
1365
1366	if (id) {
1367		if (mptcp_pm_is_userspace(msk))
1368			return mptcp_userspace_pm_get_flags_and_ifindex_by_id(msk,
1369									      id,
1370									      flags,
1371									      ifindex);
1372
1373		rcu_read_lock();
1374		entry = __lookup_addr_by_id(pm_nl_get_pernet(net), id);
1375		if (entry) {
1376			*flags = entry->flags;
1377			*ifindex = entry->ifindex;
1378		}
1379		rcu_read_unlock();
1380	}
1381
1382	return 0;
1383}
1384
1385static bool remove_anno_list_by_saddr(struct mptcp_sock *msk,
1386				      const struct mptcp_addr_info *addr)
1387{
1388	struct mptcp_pm_add_entry *entry;
1389
1390	entry = mptcp_pm_del_add_timer(msk, addr, false);
1391	if (entry) {
1392		list_del(&entry->list);
1393		kfree(entry);
1394		return true;
1395	}
1396
1397	return false;
1398}
1399
1400static bool mptcp_pm_remove_anno_addr(struct mptcp_sock *msk,
1401				      const struct mptcp_addr_info *addr,
1402				      bool force)
1403{
1404	struct mptcp_rm_list list = { .nr = 0 };
1405	bool ret;
1406
1407	list.ids[list.nr++] = addr->id;
1408
1409	ret = remove_anno_list_by_saddr(msk, addr);
1410	if (ret || force) {
1411		spin_lock_bh(&msk->pm.lock);
1412		mptcp_pm_remove_addr(msk, &list);
1413		spin_unlock_bh(&msk->pm.lock);
1414	}
1415	return ret;
1416}
1417
1418static int mptcp_nl_remove_subflow_and_signal_addr(struct net *net,
1419						   const struct mptcp_pm_addr_entry *entry)
1420{
1421	const struct mptcp_addr_info *addr = &entry->addr;
1422	struct mptcp_rm_list list = { .nr = 0 };
1423	long s_slot = 0, s_num = 0;
1424	struct mptcp_sock *msk;
1425
1426	pr_debug("remove_id=%d", addr->id);
1427
1428	list.ids[list.nr++] = addr->id;
1429
1430	while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
1431		struct sock *sk = (struct sock *)msk;
1432		bool remove_subflow;
1433
1434		if (mptcp_pm_is_userspace(msk))
1435			goto next;
1436
1437		if (list_empty(&msk->conn_list)) {
1438			mptcp_pm_remove_anno_addr(msk, addr, false);
1439			goto next;
1440		}
1441
1442		lock_sock(sk);
1443		remove_subflow = lookup_subflow_by_saddr(&msk->conn_list, addr);
1444		mptcp_pm_remove_anno_addr(msk, addr, remove_subflow &&
1445					  !(entry->flags & MPTCP_PM_ADDR_FLAG_IMPLICIT));
1446		if (remove_subflow)
1447			mptcp_pm_remove_subflow(msk, &list);
1448		release_sock(sk);
1449
1450next:
1451		sock_put(sk);
1452		cond_resched();
1453	}
1454
1455	return 0;
1456}
1457
1458static int mptcp_nl_remove_id_zero_address(struct net *net,
1459					   struct mptcp_addr_info *addr)
1460{
1461	struct mptcp_rm_list list = { .nr = 0 };
1462	long s_slot = 0, s_num = 0;
1463	struct mptcp_sock *msk;
1464
1465	list.ids[list.nr++] = 0;
1466
1467	while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
1468		struct sock *sk = (struct sock *)msk;
1469		struct mptcp_addr_info msk_local;
1470
1471		if (list_empty(&msk->conn_list) || mptcp_pm_is_userspace(msk))
1472			goto next;
1473
1474		local_address((struct sock_common *)msk, &msk_local);
1475		if (!mptcp_addresses_equal(&msk_local, addr, addr->port))
1476			goto next;
1477
1478		lock_sock(sk);
1479		spin_lock_bh(&msk->pm.lock);
1480		mptcp_pm_remove_addr(msk, &list);
1481		mptcp_pm_nl_rm_subflow_received(msk, &list);
1482		spin_unlock_bh(&msk->pm.lock);
1483		release_sock(sk);
1484
1485next:
1486		sock_put(sk);
1487		cond_resched();
1488	}
1489
1490	return 0;
1491}
1492
1493static int mptcp_nl_cmd_del_addr(struct sk_buff *skb, struct genl_info *info)
1494{
1495	struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
1496	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1497	struct mptcp_pm_addr_entry addr, *entry;
1498	unsigned int addr_max;
1499	int ret;
1500
1501	ret = mptcp_pm_parse_entry(attr, info, false, &addr);
1502	if (ret < 0)
1503		return ret;
1504
1505	/* the zero id address is special: the first address used by the msk
1506	 * always gets such an id, so different subflows can have different zero
1507	 * id addresses. Additionally zero id is not accounted for in id_bitmap.
1508	 * Let's use an 'mptcp_rm_list' instead of the common remove code.
1509	 */
1510	if (addr.addr.id == 0)
1511		return mptcp_nl_remove_id_zero_address(sock_net(skb->sk), &addr.addr);
1512
1513	spin_lock_bh(&pernet->lock);
1514	entry = __lookup_addr_by_id(pernet, addr.addr.id);
1515	if (!entry) {
1516		GENL_SET_ERR_MSG(info, "address not found");
1517		spin_unlock_bh(&pernet->lock);
1518		return -EINVAL;
1519	}
1520	if (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL) {
1521		addr_max = pernet->add_addr_signal_max;
1522		WRITE_ONCE(pernet->add_addr_signal_max, addr_max - 1);
1523	}
1524	if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) {
1525		addr_max = pernet->local_addr_max;
1526		WRITE_ONCE(pernet->local_addr_max, addr_max - 1);
1527	}
1528
1529	pernet->addrs--;
1530	list_del_rcu(&entry->list);
1531	__clear_bit(entry->addr.id, pernet->id_bitmap);
1532	spin_unlock_bh(&pernet->lock);
1533
1534	mptcp_nl_remove_subflow_and_signal_addr(sock_net(skb->sk), entry);
1535	synchronize_rcu();
1536	__mptcp_pm_release_addr_entry(entry);
1537
1538	return ret;
1539}
1540
1541void mptcp_pm_remove_addrs_and_subflows(struct mptcp_sock *msk,
1542					struct list_head *rm_list)
1543{
1544	struct mptcp_rm_list alist = { .nr = 0 }, slist = { .nr = 0 };
1545	struct mptcp_pm_addr_entry *entry;
1546
1547	list_for_each_entry(entry, rm_list, list) {
1548		if (lookup_subflow_by_saddr(&msk->conn_list, &entry->addr) &&
1549		    slist.nr < MPTCP_RM_IDS_MAX)
1550			slist.ids[slist.nr++] = entry->addr.id;
1551
1552		if (remove_anno_list_by_saddr(msk, &entry->addr) &&
1553		    alist.nr < MPTCP_RM_IDS_MAX)
1554			alist.ids[alist.nr++] = entry->addr.id;
1555	}
1556
1557	if (alist.nr) {
1558		spin_lock_bh(&msk->pm.lock);
1559		mptcp_pm_remove_addr(msk, &alist);
1560		spin_unlock_bh(&msk->pm.lock);
1561	}
1562	if (slist.nr)
1563		mptcp_pm_remove_subflow(msk, &slist);
1564}
1565
1566static void mptcp_nl_remove_addrs_list(struct net *net,
1567				       struct list_head *rm_list)
1568{
1569	long s_slot = 0, s_num = 0;
1570	struct mptcp_sock *msk;
1571
1572	if (list_empty(rm_list))
1573		return;
1574
1575	while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
1576		struct sock *sk = (struct sock *)msk;
1577
1578		if (!mptcp_pm_is_userspace(msk)) {
1579			lock_sock(sk);
1580			mptcp_pm_remove_addrs_and_subflows(msk, rm_list);
1581			release_sock(sk);
1582		}
1583
1584		sock_put(sk);
1585		cond_resched();
1586	}
1587}
1588
1589/* caller must ensure the RCU grace period is already elapsed */
1590static void __flush_addrs(struct list_head *list)
1591{
1592	while (!list_empty(list)) {
1593		struct mptcp_pm_addr_entry *cur;
1594
1595		cur = list_entry(list->next,
1596				 struct mptcp_pm_addr_entry, list);
1597		list_del_rcu(&cur->list);
1598		__mptcp_pm_release_addr_entry(cur);
1599	}
1600}
1601
1602static void __reset_counters(struct pm_nl_pernet *pernet)
1603{
1604	WRITE_ONCE(pernet->add_addr_signal_max, 0);
1605	WRITE_ONCE(pernet->add_addr_accept_max, 0);
1606	WRITE_ONCE(pernet->local_addr_max, 0);
1607	pernet->addrs = 0;
1608}
1609
1610static int mptcp_nl_cmd_flush_addrs(struct sk_buff *skb, struct genl_info *info)
1611{
1612	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1613	LIST_HEAD(free_list);
1614
1615	spin_lock_bh(&pernet->lock);
1616	list_splice_init(&pernet->local_addr_list, &free_list);
1617	__reset_counters(pernet);
1618	pernet->next_id = 1;
1619	bitmap_zero(pernet->id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
1620	spin_unlock_bh(&pernet->lock);
1621	mptcp_nl_remove_addrs_list(sock_net(skb->sk), &free_list);
1622	synchronize_rcu();
1623	__flush_addrs(&free_list);
1624	return 0;
1625}
1626
1627static int mptcp_nl_fill_addr(struct sk_buff *skb,
1628			      struct mptcp_pm_addr_entry *entry)
1629{
1630	struct mptcp_addr_info *addr = &entry->addr;
1631	struct nlattr *attr;
1632
1633	attr = nla_nest_start(skb, MPTCP_PM_ATTR_ADDR);
1634	if (!attr)
1635		return -EMSGSIZE;
1636
1637	if (nla_put_u16(skb, MPTCP_PM_ADDR_ATTR_FAMILY, addr->family))
1638		goto nla_put_failure;
1639	if (nla_put_u16(skb, MPTCP_PM_ADDR_ATTR_PORT, ntohs(addr->port)))
1640		goto nla_put_failure;
1641	if (nla_put_u8(skb, MPTCP_PM_ADDR_ATTR_ID, addr->id))
1642		goto nla_put_failure;
1643	if (nla_put_u32(skb, MPTCP_PM_ADDR_ATTR_FLAGS, entry->flags))
1644		goto nla_put_failure;
1645	if (entry->ifindex &&
1646	    nla_put_s32(skb, MPTCP_PM_ADDR_ATTR_IF_IDX, entry->ifindex))
1647		goto nla_put_failure;
1648
1649	if (addr->family == AF_INET &&
1650	    nla_put_in_addr(skb, MPTCP_PM_ADDR_ATTR_ADDR4,
1651			    addr->addr.s_addr))
1652		goto nla_put_failure;
1653#if IS_ENABLED(CONFIG_MPTCP_IPV6)
1654	else if (addr->family == AF_INET6 &&
1655		 nla_put_in6_addr(skb, MPTCP_PM_ADDR_ATTR_ADDR6, &addr->addr6))
1656		goto nla_put_failure;
1657#endif
1658	nla_nest_end(skb, attr);
1659	return 0;
1660
1661nla_put_failure:
1662	nla_nest_cancel(skb, attr);
1663	return -EMSGSIZE;
1664}
1665
1666static int mptcp_nl_cmd_get_addr(struct sk_buff *skb, struct genl_info *info)
1667{
1668	struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
1669	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1670	struct mptcp_pm_addr_entry addr, *entry;
1671	struct sk_buff *msg;
1672	void *reply;
1673	int ret;
1674
1675	ret = mptcp_pm_parse_entry(attr, info, false, &addr);
1676	if (ret < 0)
1677		return ret;
1678
1679	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1680	if (!msg)
1681		return -ENOMEM;
1682
1683	reply = genlmsg_put_reply(msg, info, &mptcp_genl_family, 0,
1684				  info->genlhdr->cmd);
1685	if (!reply) {
1686		GENL_SET_ERR_MSG(info, "not enough space in Netlink message");
1687		ret = -EMSGSIZE;
1688		goto fail;
1689	}
1690
1691	spin_lock_bh(&pernet->lock);
1692	entry = __lookup_addr_by_id(pernet, addr.addr.id);
1693	if (!entry) {
1694		GENL_SET_ERR_MSG(info, "address not found");
1695		ret = -EINVAL;
1696		goto unlock_fail;
1697	}
1698
1699	ret = mptcp_nl_fill_addr(msg, entry);
1700	if (ret)
1701		goto unlock_fail;
1702
1703	genlmsg_end(msg, reply);
1704	ret = genlmsg_reply(msg, info);
1705	spin_unlock_bh(&pernet->lock);
1706	return ret;
1707
1708unlock_fail:
1709	spin_unlock_bh(&pernet->lock);
1710
1711fail:
1712	nlmsg_free(msg);
1713	return ret;
1714}
1715
1716static int mptcp_nl_cmd_dump_addrs(struct sk_buff *msg,
1717				   struct netlink_callback *cb)
1718{
1719	struct net *net = sock_net(msg->sk);
1720	struct mptcp_pm_addr_entry *entry;
1721	struct pm_nl_pernet *pernet;
1722	int id = cb->args[0];
1723	void *hdr;
1724	int i;
1725
1726	pernet = pm_nl_get_pernet(net);
1727
1728	spin_lock_bh(&pernet->lock);
1729	for (i = id; i < MPTCP_PM_MAX_ADDR_ID + 1; i++) {
1730		if (test_bit(i, pernet->id_bitmap)) {
1731			entry = __lookup_addr_by_id(pernet, i);
1732			if (!entry)
1733				break;
1734
1735			if (entry->addr.id <= id)
1736				continue;
1737
1738			hdr = genlmsg_put(msg, NETLINK_CB(cb->skb).portid,
1739					  cb->nlh->nlmsg_seq, &mptcp_genl_family,
1740					  NLM_F_MULTI, MPTCP_PM_CMD_GET_ADDR);
1741			if (!hdr)
1742				break;
1743
1744			if (mptcp_nl_fill_addr(msg, entry) < 0) {
1745				genlmsg_cancel(msg, hdr);
1746				break;
1747			}
1748
1749			id = entry->addr.id;
1750			genlmsg_end(msg, hdr);
1751		}
1752	}
1753	spin_unlock_bh(&pernet->lock);
1754
1755	cb->args[0] = id;
1756	return msg->len;
1757}
1758
1759static int parse_limit(struct genl_info *info, int id, unsigned int *limit)
1760{
1761	struct nlattr *attr = info->attrs[id];
1762
1763	if (!attr)
1764		return 0;
1765
1766	*limit = nla_get_u32(attr);
1767	if (*limit > MPTCP_PM_ADDR_MAX) {
1768		GENL_SET_ERR_MSG(info, "limit greater than maximum");
1769		return -EINVAL;
1770	}
1771	return 0;
1772}
1773
1774static int
1775mptcp_nl_cmd_set_limits(struct sk_buff *skb, struct genl_info *info)
1776{
1777	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1778	unsigned int rcv_addrs, subflows;
1779	int ret;
1780
1781	spin_lock_bh(&pernet->lock);
1782	rcv_addrs = pernet->add_addr_accept_max;
1783	ret = parse_limit(info, MPTCP_PM_ATTR_RCV_ADD_ADDRS, &rcv_addrs);
1784	if (ret)
1785		goto unlock;
1786
1787	subflows = pernet->subflows_max;
1788	ret = parse_limit(info, MPTCP_PM_ATTR_SUBFLOWS, &subflows);
1789	if (ret)
1790		goto unlock;
1791
1792	WRITE_ONCE(pernet->add_addr_accept_max, rcv_addrs);
1793	WRITE_ONCE(pernet->subflows_max, subflows);
1794
1795unlock:
1796	spin_unlock_bh(&pernet->lock);
1797	return ret;
1798}
1799
1800static int
1801mptcp_nl_cmd_get_limits(struct sk_buff *skb, struct genl_info *info)
1802{
1803	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1804	struct sk_buff *msg;
1805	void *reply;
1806
1807	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1808	if (!msg)
1809		return -ENOMEM;
1810
1811	reply = genlmsg_put_reply(msg, info, &mptcp_genl_family, 0,
1812				  MPTCP_PM_CMD_GET_LIMITS);
1813	if (!reply)
1814		goto fail;
1815
1816	if (nla_put_u32(msg, MPTCP_PM_ATTR_RCV_ADD_ADDRS,
1817			READ_ONCE(pernet->add_addr_accept_max)))
1818		goto fail;
1819
1820	if (nla_put_u32(msg, MPTCP_PM_ATTR_SUBFLOWS,
1821			READ_ONCE(pernet->subflows_max)))
1822		goto fail;
1823
1824	genlmsg_end(msg, reply);
1825	return genlmsg_reply(msg, info);
1826
1827fail:
1828	GENL_SET_ERR_MSG(info, "not enough space in Netlink message");
1829	nlmsg_free(msg);
1830	return -EMSGSIZE;
1831}
1832
1833static void mptcp_pm_nl_fullmesh(struct mptcp_sock *msk,
1834				 struct mptcp_addr_info *addr)
1835{
1836	struct mptcp_rm_list list = { .nr = 0 };
1837
1838	list.ids[list.nr++] = addr->id;
1839
1840	spin_lock_bh(&msk->pm.lock);
1841	mptcp_pm_nl_rm_subflow_received(msk, &list);
1842	mptcp_pm_create_subflow_or_signal_addr(msk);
1843	spin_unlock_bh(&msk->pm.lock);
1844}
1845
1846static int mptcp_nl_set_flags(struct net *net,
1847			      struct mptcp_addr_info *addr,
1848			      u8 bkup, u8 changed)
1849{
1850	long s_slot = 0, s_num = 0;
1851	struct mptcp_sock *msk;
1852	int ret = -EINVAL;
1853
1854	while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
1855		struct sock *sk = (struct sock *)msk;
1856
1857		if (list_empty(&msk->conn_list) || mptcp_pm_is_userspace(msk))
1858			goto next;
1859
1860		lock_sock(sk);
1861		if (changed & MPTCP_PM_ADDR_FLAG_BACKUP)
1862			ret = mptcp_pm_nl_mp_prio_send_ack(msk, addr, NULL, bkup);
1863		if (changed & MPTCP_PM_ADDR_FLAG_FULLMESH)
1864			mptcp_pm_nl_fullmesh(msk, addr);
1865		release_sock(sk);
1866
1867next:
1868		sock_put(sk);
1869		cond_resched();
1870	}
1871
1872	return ret;
1873}
1874
1875static int mptcp_nl_cmd_set_flags(struct sk_buff *skb, struct genl_info *info)
1876{
1877	struct mptcp_pm_addr_entry addr = { .addr = { .family = AF_UNSPEC }, }, *entry;
1878	struct mptcp_pm_addr_entry remote = { .addr = { .family = AF_UNSPEC }, };
1879	struct nlattr *attr_rem = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
1880	struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN];
1881	struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
1882	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1883	u8 changed, mask = MPTCP_PM_ADDR_FLAG_BACKUP |
1884			   MPTCP_PM_ADDR_FLAG_FULLMESH;
1885	struct net *net = sock_net(skb->sk);
1886	u8 bkup = 0, lookup_by_id = 0;
1887	int ret;
1888
1889	ret = mptcp_pm_parse_entry(attr, info, false, &addr);
1890	if (ret < 0)
1891		return ret;
1892
1893	if (attr_rem) {
1894		ret = mptcp_pm_parse_entry(attr_rem, info, false, &remote);
1895		if (ret < 0)
1896			return ret;
1897	}
1898
1899	if (addr.flags & MPTCP_PM_ADDR_FLAG_BACKUP)
1900		bkup = 1;
1901	if (addr.addr.family == AF_UNSPEC) {
1902		lookup_by_id = 1;
1903		if (!addr.addr.id)
1904			return -EOPNOTSUPP;
1905	}
1906
1907	if (token)
1908		return mptcp_userspace_pm_set_flags(sock_net(skb->sk),
1909						    token, &addr, &remote, bkup);
1910
1911	spin_lock_bh(&pernet->lock);
1912	entry = __lookup_addr(pernet, &addr.addr, lookup_by_id);
1913	if (!entry) {
1914		spin_unlock_bh(&pernet->lock);
1915		return -EINVAL;
1916	}
1917	if ((addr.flags & MPTCP_PM_ADDR_FLAG_FULLMESH) &&
1918	    (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL)) {
1919		spin_unlock_bh(&pernet->lock);
1920		return -EINVAL;
1921	}
1922
1923	changed = (addr.flags ^ entry->flags) & mask;
1924	entry->flags = (entry->flags & ~mask) | (addr.flags & mask);
1925	addr = *entry;
1926	spin_unlock_bh(&pernet->lock);
1927
1928	mptcp_nl_set_flags(net, &addr.addr, bkup, changed);
1929	return 0;
1930}
1931
1932static void mptcp_nl_mcast_send(struct net *net, struct sk_buff *nlskb, gfp_t gfp)
1933{
1934	genlmsg_multicast_netns(&mptcp_genl_family, net,
1935				nlskb, 0, MPTCP_PM_EV_GRP_OFFSET, gfp);
1936}
1937
1938bool mptcp_userspace_pm_active(const struct mptcp_sock *msk)
1939{
1940	return genl_has_listeners(&mptcp_genl_family,
1941				  sock_net((const struct sock *)msk),
1942				  MPTCP_PM_EV_GRP_OFFSET);
1943}
1944
1945static int mptcp_event_add_subflow(struct sk_buff *skb, const struct sock *ssk)
1946{
1947	const struct inet_sock *issk = inet_sk(ssk);
1948	const struct mptcp_subflow_context *sf;
1949
1950	if (nla_put_u16(skb, MPTCP_ATTR_FAMILY, ssk->sk_family))
1951		return -EMSGSIZE;
1952
1953	switch (ssk->sk_family) {
1954	case AF_INET:
1955		if (nla_put_in_addr(skb, MPTCP_ATTR_SADDR4, issk->inet_saddr))
1956			return -EMSGSIZE;
1957		if (nla_put_in_addr(skb, MPTCP_ATTR_DADDR4, issk->inet_daddr))
1958			return -EMSGSIZE;
1959		break;
1960#if IS_ENABLED(CONFIG_MPTCP_IPV6)
1961	case AF_INET6: {
1962		const struct ipv6_pinfo *np = inet6_sk(ssk);
1963
1964		if (nla_put_in6_addr(skb, MPTCP_ATTR_SADDR6, &np->saddr))
1965			return -EMSGSIZE;
1966		if (nla_put_in6_addr(skb, MPTCP_ATTR_DADDR6, &ssk->sk_v6_daddr))
1967			return -EMSGSIZE;
1968		break;
1969	}
1970#endif
1971	default:
1972		WARN_ON_ONCE(1);
1973		return -EMSGSIZE;
1974	}
1975
1976	if (nla_put_be16(skb, MPTCP_ATTR_SPORT, issk->inet_sport))
1977		return -EMSGSIZE;
1978	if (nla_put_be16(skb, MPTCP_ATTR_DPORT, issk->inet_dport))
1979		return -EMSGSIZE;
1980
1981	sf = mptcp_subflow_ctx(ssk);
1982	if (WARN_ON_ONCE(!sf))
1983		return -EINVAL;
1984
1985	if (nla_put_u8(skb, MPTCP_ATTR_LOC_ID, sf->local_id))
1986		return -EMSGSIZE;
1987
1988	if (nla_put_u8(skb, MPTCP_ATTR_REM_ID, sf->remote_id))
1989		return -EMSGSIZE;
1990
1991	return 0;
1992}
1993
1994static int mptcp_event_put_token_and_ssk(struct sk_buff *skb,
1995					 const struct mptcp_sock *msk,
1996					 const struct sock *ssk)
1997{
1998	const struct sock *sk = (const struct sock *)msk;
1999	const struct mptcp_subflow_context *sf;
2000	u8 sk_err;
2001
2002	if (nla_put_u32(skb, MPTCP_ATTR_TOKEN, msk->token))
2003		return -EMSGSIZE;
2004
2005	if (mptcp_event_add_subflow(skb, ssk))
2006		return -EMSGSIZE;
2007
2008	sf = mptcp_subflow_ctx(ssk);
2009	if (WARN_ON_ONCE(!sf))
2010		return -EINVAL;
2011
2012	if (nla_put_u8(skb, MPTCP_ATTR_BACKUP, sf->backup))
2013		return -EMSGSIZE;
2014
2015	if (ssk->sk_bound_dev_if &&
2016	    nla_put_s32(skb, MPTCP_ATTR_IF_IDX, ssk->sk_bound_dev_if))
2017		return -EMSGSIZE;
2018
2019	sk_err = ssk->sk_err;
2020	if (sk_err && sk->sk_state == TCP_ESTABLISHED &&
2021	    nla_put_u8(skb, MPTCP_ATTR_ERROR, sk_err))
2022		return -EMSGSIZE;
2023
2024	return 0;
2025}
2026
2027static int mptcp_event_sub_established(struct sk_buff *skb,
2028				       const struct mptcp_sock *msk,
2029				       const struct sock *ssk)
2030{
2031	return mptcp_event_put_token_and_ssk(skb, msk, ssk);
2032}
2033
2034static int mptcp_event_sub_closed(struct sk_buff *skb,
2035				  const struct mptcp_sock *msk,
2036				  const struct sock *ssk)
2037{
2038	const struct mptcp_subflow_context *sf;
2039
2040	if (mptcp_event_put_token_and_ssk(skb, msk, ssk))
2041		return -EMSGSIZE;
2042
2043	sf = mptcp_subflow_ctx(ssk);
2044	if (!sf->reset_seen)
2045		return 0;
2046
2047	if (nla_put_u32(skb, MPTCP_ATTR_RESET_REASON, sf->reset_reason))
2048		return -EMSGSIZE;
2049
2050	if (nla_put_u32(skb, MPTCP_ATTR_RESET_FLAGS, sf->reset_transient))
2051		return -EMSGSIZE;
2052
2053	return 0;
2054}
2055
2056static int mptcp_event_created(struct sk_buff *skb,
2057			       const struct mptcp_sock *msk,
2058			       const struct sock *ssk)
2059{
2060	int err = nla_put_u32(skb, MPTCP_ATTR_TOKEN, msk->token);
2061
2062	if (err)
2063		return err;
2064
2065	if (nla_put_u8(skb, MPTCP_ATTR_SERVER_SIDE, READ_ONCE(msk->pm.server_side)))
2066		return -EMSGSIZE;
2067
2068	return mptcp_event_add_subflow(skb, ssk);
2069}
2070
2071void mptcp_event_addr_removed(const struct mptcp_sock *msk, uint8_t id)
2072{
2073	struct net *net = sock_net((const struct sock *)msk);
2074	struct nlmsghdr *nlh;
2075	struct sk_buff *skb;
2076
2077	if (!genl_has_listeners(&mptcp_genl_family, net, MPTCP_PM_EV_GRP_OFFSET))
2078		return;
2079
2080	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
2081	if (!skb)
2082		return;
2083
2084	nlh = genlmsg_put(skb, 0, 0, &mptcp_genl_family, 0, MPTCP_EVENT_REMOVED);
2085	if (!nlh)
2086		goto nla_put_failure;
2087
2088	if (nla_put_u32(skb, MPTCP_ATTR_TOKEN, msk->token))
2089		goto nla_put_failure;
2090
2091	if (nla_put_u8(skb, MPTCP_ATTR_REM_ID, id))
2092		goto nla_put_failure;
2093
2094	genlmsg_end(skb, nlh);
2095	mptcp_nl_mcast_send(net, skb, GFP_ATOMIC);
2096	return;
2097
2098nla_put_failure:
2099	nlmsg_free(skb);
2100}
2101
2102void mptcp_event_addr_announced(const struct sock *ssk,
2103				const struct mptcp_addr_info *info)
2104{
2105	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
2106	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
2107	struct net *net = sock_net(ssk);
2108	struct nlmsghdr *nlh;
2109	struct sk_buff *skb;
2110
2111	if (!genl_has_listeners(&mptcp_genl_family, net, MPTCP_PM_EV_GRP_OFFSET))
2112		return;
2113
2114	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
2115	if (!skb)
2116		return;
2117
2118	nlh = genlmsg_put(skb, 0, 0, &mptcp_genl_family, 0,
2119			  MPTCP_EVENT_ANNOUNCED);
2120	if (!nlh)
2121		goto nla_put_failure;
2122
2123	if (nla_put_u32(skb, MPTCP_ATTR_TOKEN, msk->token))
2124		goto nla_put_failure;
2125
2126	if (nla_put_u8(skb, MPTCP_ATTR_REM_ID, info->id))
2127		goto nla_put_failure;
2128
2129	if (nla_put_be16(skb, MPTCP_ATTR_DPORT,
2130			 info->port == 0 ?
2131			 inet_sk(ssk)->inet_dport :
2132			 info->port))
2133		goto nla_put_failure;
2134
2135	switch (info->family) {
2136	case AF_INET:
2137		if (nla_put_in_addr(skb, MPTCP_ATTR_DADDR4, info->addr.s_addr))
2138			goto nla_put_failure;
2139		break;
2140#if IS_ENABLED(CONFIG_MPTCP_IPV6)
2141	case AF_INET6:
2142		if (nla_put_in6_addr(skb, MPTCP_ATTR_DADDR6, &info->addr6))
2143			goto nla_put_failure;
2144		break;
2145#endif
2146	default:
2147		WARN_ON_ONCE(1);
2148		goto nla_put_failure;
2149	}
2150
2151	genlmsg_end(skb, nlh);
2152	mptcp_nl_mcast_send(net, skb, GFP_ATOMIC);
2153	return;
2154
2155nla_put_failure:
2156	nlmsg_free(skb);
2157}
2158
2159void mptcp_event_pm_listener(const struct sock *ssk,
2160			     enum mptcp_event_type event)
2161{
2162	const struct inet_sock *issk = inet_sk(ssk);
2163	struct net *net = sock_net(ssk);
2164	struct nlmsghdr *nlh;
2165	struct sk_buff *skb;
2166
2167	if (!genl_has_listeners(&mptcp_genl_family, net, MPTCP_PM_EV_GRP_OFFSET))
2168		return;
2169
2170	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
2171	if (!skb)
2172		return;
2173
2174	nlh = genlmsg_put(skb, 0, 0, &mptcp_genl_family, 0, event);
2175	if (!nlh)
2176		goto nla_put_failure;
2177
2178	if (nla_put_u16(skb, MPTCP_ATTR_FAMILY, ssk->sk_family))
2179		goto nla_put_failure;
2180
2181	if (nla_put_be16(skb, MPTCP_ATTR_SPORT, issk->inet_sport))
2182		goto nla_put_failure;
2183
2184	switch (ssk->sk_family) {
2185	case AF_INET:
2186		if (nla_put_in_addr(skb, MPTCP_ATTR_SADDR4, issk->inet_saddr))
2187			goto nla_put_failure;
2188		break;
2189#if IS_ENABLED(CONFIG_MPTCP_IPV6)
2190	case AF_INET6: {
2191		const struct ipv6_pinfo *np = inet6_sk(ssk);
2192
2193		if (nla_put_in6_addr(skb, MPTCP_ATTR_SADDR6, &np->saddr))
2194			goto nla_put_failure;
2195		break;
2196	}
2197#endif
2198	default:
2199		WARN_ON_ONCE(1);
2200		goto nla_put_failure;
2201	}
2202
2203	genlmsg_end(skb, nlh);
2204	mptcp_nl_mcast_send(net, skb, GFP_KERNEL);
2205	return;
2206
2207nla_put_failure:
2208	nlmsg_free(skb);
2209}
2210
2211void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
2212		 const struct sock *ssk, gfp_t gfp)
2213{
2214	struct net *net = sock_net((const struct sock *)msk);
2215	struct nlmsghdr *nlh;
2216	struct sk_buff *skb;
2217
2218	if (!genl_has_listeners(&mptcp_genl_family, net, MPTCP_PM_EV_GRP_OFFSET))
2219		return;
2220
2221	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, gfp);
2222	if (!skb)
2223		return;
2224
2225	nlh = genlmsg_put(skb, 0, 0, &mptcp_genl_family, 0, type);
2226	if (!nlh)
2227		goto nla_put_failure;
2228
2229	switch (type) {
2230	case MPTCP_EVENT_UNSPEC:
2231		WARN_ON_ONCE(1);
2232		break;
2233	case MPTCP_EVENT_CREATED:
2234	case MPTCP_EVENT_ESTABLISHED:
2235		if (mptcp_event_created(skb, msk, ssk) < 0)
2236			goto nla_put_failure;
2237		break;
2238	case MPTCP_EVENT_CLOSED:
2239		if (nla_put_u32(skb, MPTCP_ATTR_TOKEN, msk->token) < 0)
2240			goto nla_put_failure;
2241		break;
2242	case MPTCP_EVENT_ANNOUNCED:
2243	case MPTCP_EVENT_REMOVED:
2244		/* call mptcp_event_addr_announced()/removed instead */
2245		WARN_ON_ONCE(1);
2246		break;
2247	case MPTCP_EVENT_SUB_ESTABLISHED:
2248	case MPTCP_EVENT_SUB_PRIORITY:
2249		if (mptcp_event_sub_established(skb, msk, ssk) < 0)
2250			goto nla_put_failure;
2251		break;
2252	case MPTCP_EVENT_SUB_CLOSED:
2253		if (mptcp_event_sub_closed(skb, msk, ssk) < 0)
2254			goto nla_put_failure;
2255		break;
2256	case MPTCP_EVENT_LISTENER_CREATED:
2257	case MPTCP_EVENT_LISTENER_CLOSED:
2258		break;
2259	}
2260
2261	genlmsg_end(skb, nlh);
2262	mptcp_nl_mcast_send(net, skb, gfp);
2263	return;
2264
2265nla_put_failure:
2266	nlmsg_free(skb);
2267}
2268
2269static const struct genl_small_ops mptcp_pm_ops[] = {
2270	{
2271		.cmd    = MPTCP_PM_CMD_ADD_ADDR,
2272		.doit   = mptcp_nl_cmd_add_addr,
2273		.flags  = GENL_UNS_ADMIN_PERM,
2274	},
2275	{
2276		.cmd    = MPTCP_PM_CMD_DEL_ADDR,
2277		.doit   = mptcp_nl_cmd_del_addr,
2278		.flags  = GENL_UNS_ADMIN_PERM,
2279	},
2280	{
2281		.cmd    = MPTCP_PM_CMD_FLUSH_ADDRS,
2282		.doit   = mptcp_nl_cmd_flush_addrs,
2283		.flags  = GENL_UNS_ADMIN_PERM,
2284	},
2285	{
2286		.cmd    = MPTCP_PM_CMD_GET_ADDR,
2287		.doit   = mptcp_nl_cmd_get_addr,
2288		.dumpit   = mptcp_nl_cmd_dump_addrs,
2289	},
2290	{
2291		.cmd    = MPTCP_PM_CMD_SET_LIMITS,
2292		.doit   = mptcp_nl_cmd_set_limits,
2293		.flags  = GENL_UNS_ADMIN_PERM,
2294	},
2295	{
2296		.cmd    = MPTCP_PM_CMD_GET_LIMITS,
2297		.doit   = mptcp_nl_cmd_get_limits,
2298	},
2299	{
2300		.cmd    = MPTCP_PM_CMD_SET_FLAGS,
2301		.doit   = mptcp_nl_cmd_set_flags,
2302		.flags  = GENL_UNS_ADMIN_PERM,
2303	},
2304	{
2305		.cmd    = MPTCP_PM_CMD_ANNOUNCE,
2306		.doit   = mptcp_nl_cmd_announce,
2307		.flags  = GENL_UNS_ADMIN_PERM,
2308	},
2309	{
2310		.cmd    = MPTCP_PM_CMD_REMOVE,
2311		.doit   = mptcp_nl_cmd_remove,
2312		.flags  = GENL_UNS_ADMIN_PERM,
2313	},
2314	{
2315		.cmd    = MPTCP_PM_CMD_SUBFLOW_CREATE,
2316		.doit   = mptcp_nl_cmd_sf_create,
2317		.flags  = GENL_UNS_ADMIN_PERM,
2318	},
2319	{
2320		.cmd    = MPTCP_PM_CMD_SUBFLOW_DESTROY,
2321		.doit   = mptcp_nl_cmd_sf_destroy,
2322		.flags  = GENL_UNS_ADMIN_PERM,
2323	},
2324};
2325
2326static struct genl_family mptcp_genl_family __ro_after_init = {
2327	.name		= MPTCP_PM_NAME,
2328	.version	= MPTCP_PM_VER,
2329	.maxattr	= MPTCP_PM_ATTR_MAX,
2330	.policy		= mptcp_pm_policy,
2331	.netnsok	= true,
2332	.module		= THIS_MODULE,
2333	.small_ops	= mptcp_pm_ops,
2334	.n_small_ops	= ARRAY_SIZE(mptcp_pm_ops),
2335	.resv_start_op	= MPTCP_PM_CMD_SUBFLOW_DESTROY + 1,
2336	.mcgrps		= mptcp_pm_mcgrps,
2337	.n_mcgrps	= ARRAY_SIZE(mptcp_pm_mcgrps),
2338};
2339
2340static int __net_init pm_nl_init_net(struct net *net)
2341{
2342	struct pm_nl_pernet *pernet = pm_nl_get_pernet(net);
2343
2344	INIT_LIST_HEAD_RCU(&pernet->local_addr_list);
2345
2346	/* Cit. 2 subflows ought to be enough for anybody. */
2347	pernet->subflows_max = 2;
2348	pernet->next_id = 1;
2349	pernet->stale_loss_cnt = 4;
2350	spin_lock_init(&pernet->lock);
2351
2352	/* No need to initialize other pernet fields, the struct is zeroed at
2353	 * allocation time.
2354	 */
2355
2356	return 0;
2357}
2358
2359static void __net_exit pm_nl_exit_net(struct list_head *net_list)
2360{
2361	struct net *net;
2362
2363	list_for_each_entry(net, net_list, exit_list) {
2364		struct pm_nl_pernet *pernet = pm_nl_get_pernet(net);
2365
2366		/* net is removed from namespace list, can't race with
2367		 * other modifiers, also netns core already waited for a
2368		 * RCU grace period.
2369		 */
2370		__flush_addrs(&pernet->local_addr_list);
2371	}
2372}
2373
2374static struct pernet_operations mptcp_pm_pernet_ops = {
2375	.init = pm_nl_init_net,
2376	.exit_batch = pm_nl_exit_net,
2377	.id = &pm_nl_pernet_id,
2378	.size = sizeof(struct pm_nl_pernet),
2379};
2380
2381void __init mptcp_pm_nl_init(void)
2382{
2383	if (register_pernet_subsys(&mptcp_pm_pernet_ops) < 0)
2384		panic("Failed to register MPTCP PM pernet subsystem.\n");
2385
2386	if (genl_register_family(&mptcp_genl_family))
2387		panic("Failed to register MPTCP PM netlink family\n");
2388}