xref: /linux/net/mptcp/pm_kernel.c (revision de5ca699bc3f7fe9f90ba927d8a6e7783cd7311d)
1 // SPDX-License-Identifier: GPL-2.0
2 /* Multipath TCP
3  *
4  * Copyright (c) 2025, Matthieu Baerts.
5  */
6 
7 #define pr_fmt(fmt) "MPTCP: " fmt
8 
9 #include <net/netns/generic.h>
10 
11 #include "protocol.h"
12 #include "mib.h"
13 #include "mptcp_pm_gen.h"
14 
15 static int pm_nl_pernet_id;
16 
17 struct pm_nl_pernet {
18 	/* protects pernet updates */
19 	spinlock_t		lock;
20 	struct list_head	local_addr_list;
21 	unsigned int		addrs;
22 	unsigned int		stale_loss_cnt;
23 	unsigned int		add_addr_signal_max;
24 	unsigned int		add_addr_accept_max;
25 	unsigned int		local_addr_max;
26 	unsigned int		subflows_max;
27 	unsigned int		next_id;
28 	DECLARE_BITMAP(id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
29 };
30 
31 #define MPTCP_PM_ADDR_MAX	8
32 
33 static struct pm_nl_pernet *pm_nl_get_pernet(const struct net *net)
34 {
35 	return net_generic(net, pm_nl_pernet_id);
36 }
37 
38 static struct pm_nl_pernet *
39 pm_nl_get_pernet_from_msk(const struct mptcp_sock *msk)
40 {
41 	return pm_nl_get_pernet(sock_net((struct sock *)msk));
42 }
43 
44 static struct pm_nl_pernet *genl_info_pm_nl(struct genl_info *info)
45 {
46 	return pm_nl_get_pernet(genl_info_net(info));
47 }
48 
49 unsigned int mptcp_pm_get_add_addr_signal_max(const struct mptcp_sock *msk)
50 {
51 	const struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
52 
53 	return READ_ONCE(pernet->add_addr_signal_max);
54 }
55 EXPORT_SYMBOL_GPL(mptcp_pm_get_add_addr_signal_max);
56 
57 unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk)
58 {
59 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
60 
61 	return READ_ONCE(pernet->add_addr_accept_max);
62 }
63 EXPORT_SYMBOL_GPL(mptcp_pm_get_add_addr_accept_max);
64 
65 unsigned int mptcp_pm_get_subflows_max(const struct mptcp_sock *msk)
66 {
67 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
68 
69 	return READ_ONCE(pernet->subflows_max);
70 }
71 EXPORT_SYMBOL_GPL(mptcp_pm_get_subflows_max);
72 
73 unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk)
74 {
75 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
76 
77 	return READ_ONCE(pernet->local_addr_max);
78 }
79 EXPORT_SYMBOL_GPL(mptcp_pm_get_local_addr_max);
80 
81 static bool lookup_subflow_by_daddr(const struct list_head *list,
82 				    const struct mptcp_addr_info *daddr)
83 {
84 	struct mptcp_subflow_context *subflow;
85 	struct mptcp_addr_info cur;
86 
87 	list_for_each_entry(subflow, list, node) {
88 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
89 
90 		if (!((1 << inet_sk_state_load(ssk)) &
91 		      (TCPF_ESTABLISHED | TCPF_SYN_SENT | TCPF_SYN_RECV)))
92 			continue;
93 
94 		mptcp_remote_address((struct sock_common *)ssk, &cur);
95 		if (mptcp_addresses_equal(&cur, daddr, daddr->port))
96 			return true;
97 	}
98 
99 	return false;
100 }
101 
102 static bool
103 select_local_address(const struct pm_nl_pernet *pernet,
104 		     const struct mptcp_sock *msk,
105 		     struct mptcp_pm_local *new_local)
106 {
107 	struct mptcp_pm_addr_entry *entry;
108 	bool found = false;
109 
110 	msk_owned_by_me(msk);
111 
112 	rcu_read_lock();
113 	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
114 		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW))
115 			continue;
116 
117 		if (!test_bit(entry->addr.id, msk->pm.id_avail_bitmap))
118 			continue;
119 
120 		new_local->addr = entry->addr;
121 		new_local->flags = entry->flags;
122 		new_local->ifindex = entry->ifindex;
123 		found = true;
124 		break;
125 	}
126 	rcu_read_unlock();
127 
128 	return found;
129 }
130 
131 static bool
132 select_signal_address(struct pm_nl_pernet *pernet, const struct mptcp_sock *msk,
133 		      struct mptcp_pm_local *new_local)
134 {
135 	struct mptcp_pm_addr_entry *entry;
136 	bool found = false;
137 
138 	rcu_read_lock();
139 	/* do not keep any additional per socket state, just signal
140 	 * the address list in order.
141 	 * Note: removal from the local address list during the msk life-cycle
142 	 * can lead to additional addresses not being announced.
143 	 */
144 	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
145 		if (!test_bit(entry->addr.id, msk->pm.id_avail_bitmap))
146 			continue;
147 
148 		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL))
149 			continue;
150 
151 		new_local->addr = entry->addr;
152 		new_local->flags = entry->flags;
153 		new_local->ifindex = entry->ifindex;
154 		found = true;
155 		break;
156 	}
157 	rcu_read_unlock();
158 
159 	return found;
160 }
161 
162 /* Fill all the remote addresses into the array addrs[],
163  * and return the array size.
164  */
165 static unsigned int fill_remote_addresses_vec(struct mptcp_sock *msk,
166 					      struct mptcp_addr_info *local,
167 					      bool fullmesh,
168 					      struct mptcp_addr_info *addrs)
169 {
170 	bool deny_id0 = READ_ONCE(msk->pm.remote_deny_join_id0);
171 	struct sock *sk = (struct sock *)msk, *ssk;
172 	struct mptcp_subflow_context *subflow;
173 	struct mptcp_addr_info remote = { 0 };
174 	unsigned int subflows_max;
175 	int i = 0;
176 
177 	subflows_max = mptcp_pm_get_subflows_max(msk);
178 	mptcp_remote_address((struct sock_common *)sk, &remote);
179 
180 	/* Non-fullmesh endpoint, fill in the single entry
181 	 * corresponding to the primary MPC subflow remote address
182 	 */
183 	if (!fullmesh) {
184 		if (deny_id0)
185 			return 0;
186 
187 		if (!mptcp_pm_addr_families_match(sk, local, &remote))
188 			return 0;
189 
190 		msk->pm.subflows++;
191 		addrs[i++] = remote;
192 	} else {
193 		DECLARE_BITMAP(unavail_id, MPTCP_PM_MAX_ADDR_ID + 1);
194 
195 		/* Forbid creation of new subflows matching existing
196 		 * ones, possibly already created by incoming ADD_ADDR
197 		 */
198 		bitmap_zero(unavail_id, MPTCP_PM_MAX_ADDR_ID + 1);
199 		mptcp_for_each_subflow(msk, subflow)
200 			if (READ_ONCE(subflow->local_id) == local->id)
201 				__set_bit(subflow->remote_id, unavail_id);
202 
203 		mptcp_for_each_subflow(msk, subflow) {
204 			ssk = mptcp_subflow_tcp_sock(subflow);
205 			mptcp_remote_address((struct sock_common *)ssk, &addrs[i]);
206 			addrs[i].id = READ_ONCE(subflow->remote_id);
207 			if (deny_id0 && !addrs[i].id)
208 				continue;
209 
210 			if (test_bit(addrs[i].id, unavail_id))
211 				continue;
212 
213 			if (!mptcp_pm_addr_families_match(sk, local, &addrs[i]))
214 				continue;
215 
216 			if (msk->pm.subflows < subflows_max) {
217 				/* forbid creating multiple address towards
218 				 * this id
219 				 */
220 				__set_bit(addrs[i].id, unavail_id);
221 				msk->pm.subflows++;
222 				i++;
223 			}
224 		}
225 	}
226 
227 	return i;
228 }
229 
230 static struct mptcp_pm_addr_entry *
231 __lookup_addr_by_id(struct pm_nl_pernet *pernet, unsigned int id)
232 {
233 	struct mptcp_pm_addr_entry *entry;
234 
235 	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list,
236 				lockdep_is_held(&pernet->lock)) {
237 		if (entry->addr.id == id)
238 			return entry;
239 	}
240 	return NULL;
241 }
242 
243 static struct mptcp_pm_addr_entry *
244 __lookup_addr(struct pm_nl_pernet *pernet, const struct mptcp_addr_info *info)
245 {
246 	struct mptcp_pm_addr_entry *entry;
247 
248 	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list,
249 				lockdep_is_held(&pernet->lock)) {
250 		if (mptcp_addresses_equal(&entry->addr, info, entry->addr.port))
251 			return entry;
252 	}
253 	return NULL;
254 }
255 
256 static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
257 {
258 	struct sock *sk = (struct sock *)msk;
259 	unsigned int add_addr_signal_max;
260 	bool signal_and_subflow = false;
261 	unsigned int local_addr_max;
262 	struct pm_nl_pernet *pernet;
263 	struct mptcp_pm_local local;
264 	unsigned int subflows_max;
265 
266 	pernet = pm_nl_get_pernet(sock_net(sk));
267 
268 	add_addr_signal_max = mptcp_pm_get_add_addr_signal_max(msk);
269 	local_addr_max = mptcp_pm_get_local_addr_max(msk);
270 	subflows_max = mptcp_pm_get_subflows_max(msk);
271 
272 	/* do lazy endpoint usage accounting for the MPC subflows */
273 	if (unlikely(!(msk->pm.status & BIT(MPTCP_PM_MPC_ENDPOINT_ACCOUNTED))) && msk->first) {
274 		struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(msk->first);
275 		struct mptcp_pm_addr_entry *entry;
276 		struct mptcp_addr_info mpc_addr;
277 		bool backup = false;
278 
279 		mptcp_local_address((struct sock_common *)msk->first, &mpc_addr);
280 		rcu_read_lock();
281 		entry = __lookup_addr(pernet, &mpc_addr);
282 		if (entry) {
283 			__clear_bit(entry->addr.id, msk->pm.id_avail_bitmap);
284 			msk->mpc_endpoint_id = entry->addr.id;
285 			backup = !!(entry->flags & MPTCP_PM_ADDR_FLAG_BACKUP);
286 		}
287 		rcu_read_unlock();
288 
289 		if (backup)
290 			mptcp_pm_send_ack(msk, subflow, true, backup);
291 
292 		msk->pm.status |= BIT(MPTCP_PM_MPC_ENDPOINT_ACCOUNTED);
293 	}
294 
295 	pr_debug("local %d:%d signal %d:%d subflows %d:%d\n",
296 		 msk->pm.local_addr_used, local_addr_max,
297 		 msk->pm.add_addr_signaled, add_addr_signal_max,
298 		 msk->pm.subflows, subflows_max);
299 
300 	/* check first for announce */
301 	if (msk->pm.add_addr_signaled < add_addr_signal_max) {
302 		/* due to racing events on both ends we can reach here while
303 		 * previous add address is still running: if we invoke now
304 		 * mptcp_pm_announce_addr(), that will fail and the
305 		 * corresponding id will be marked as used.
306 		 * Instead let the PM machinery reschedule us when the
307 		 * current address announce will be completed.
308 		 */
309 		if (msk->pm.addr_signal & BIT(MPTCP_ADD_ADDR_SIGNAL))
310 			return;
311 
312 		if (!select_signal_address(pernet, msk, &local))
313 			goto subflow;
314 
315 		/* If the alloc fails, we are on memory pressure, not worth
316 		 * continuing, and trying to create subflows.
317 		 */
318 		if (!mptcp_pm_alloc_anno_list(msk, &local.addr))
319 			return;
320 
321 		__clear_bit(local.addr.id, msk->pm.id_avail_bitmap);
322 		msk->pm.add_addr_signaled++;
323 
324 		/* Special case for ID0: set the correct ID */
325 		if (local.addr.id == msk->mpc_endpoint_id)
326 			local.addr.id = 0;
327 
328 		mptcp_pm_announce_addr(msk, &local.addr, false);
329 		mptcp_pm_addr_send_ack(msk);
330 
331 		if (local.flags & MPTCP_PM_ADDR_FLAG_SUBFLOW)
332 			signal_and_subflow = true;
333 	}
334 
335 subflow:
336 	/* check if should create a new subflow */
337 	while (msk->pm.local_addr_used < local_addr_max &&
338 	       msk->pm.subflows < subflows_max) {
339 		struct mptcp_addr_info addrs[MPTCP_PM_ADDR_MAX];
340 		bool fullmesh;
341 		int i, nr;
342 
343 		if (signal_and_subflow)
344 			signal_and_subflow = false;
345 		else if (!select_local_address(pernet, msk, &local))
346 			break;
347 
348 		fullmesh = !!(local.flags & MPTCP_PM_ADDR_FLAG_FULLMESH);
349 
350 		__clear_bit(local.addr.id, msk->pm.id_avail_bitmap);
351 
352 		/* Special case for ID0: set the correct ID */
353 		if (local.addr.id == msk->mpc_endpoint_id)
354 			local.addr.id = 0;
355 		else /* local_addr_used is not decr for ID 0 */
356 			msk->pm.local_addr_used++;
357 
358 		nr = fill_remote_addresses_vec(msk, &local.addr, fullmesh, addrs);
359 		if (nr == 0)
360 			continue;
361 
362 		spin_unlock_bh(&msk->pm.lock);
363 		for (i = 0; i < nr; i++)
364 			__mptcp_subflow_connect(sk, &local, &addrs[i]);
365 		spin_lock_bh(&msk->pm.lock);
366 	}
367 	mptcp_pm_nl_check_work_pending(msk);
368 }
369 
370 static void mptcp_pm_nl_fully_established(struct mptcp_sock *msk)
371 {
372 	mptcp_pm_create_subflow_or_signal_addr(msk);
373 }
374 
375 static void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk)
376 {
377 	mptcp_pm_create_subflow_or_signal_addr(msk);
378 }
379 
380 /* Fill all the local addresses into the array addrs[],
381  * and return the array size.
382  */
383 static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
384 					     struct mptcp_addr_info *remote,
385 					     struct mptcp_pm_local *locals)
386 {
387 	struct sock *sk = (struct sock *)msk;
388 	struct mptcp_pm_addr_entry *entry;
389 	struct mptcp_addr_info mpc_addr;
390 	struct pm_nl_pernet *pernet;
391 	unsigned int subflows_max;
392 	int i = 0;
393 
394 	pernet = pm_nl_get_pernet_from_msk(msk);
395 	subflows_max = mptcp_pm_get_subflows_max(msk);
396 
397 	mptcp_local_address((struct sock_common *)msk, &mpc_addr);
398 
399 	rcu_read_lock();
400 	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
401 		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_FULLMESH))
402 			continue;
403 
404 		if (!mptcp_pm_addr_families_match(sk, &entry->addr, remote))
405 			continue;
406 
407 		if (msk->pm.subflows < subflows_max) {
408 			locals[i].addr = entry->addr;
409 			locals[i].flags = entry->flags;
410 			locals[i].ifindex = entry->ifindex;
411 
412 			/* Special case for ID0: set the correct ID */
413 			if (mptcp_addresses_equal(&locals[i].addr, &mpc_addr, locals[i].addr.port))
414 				locals[i].addr.id = 0;
415 
416 			msk->pm.subflows++;
417 			i++;
418 		}
419 	}
420 	rcu_read_unlock();
421 
422 	/* If the array is empty, fill in the single
423 	 * 'IPADDRANY' local address
424 	 */
425 	if (!i) {
426 		memset(&locals[i], 0, sizeof(locals[i]));
427 		locals[i].addr.family =
428 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
429 			       remote->family == AF_INET6 &&
430 			       ipv6_addr_v4mapped(&remote->addr6) ? AF_INET :
431 #endif
432 			       remote->family;
433 
434 		if (!mptcp_pm_addr_families_match(sk, &locals[i].addr, remote))
435 			return 0;
436 
437 		msk->pm.subflows++;
438 		i++;
439 	}
440 
441 	return i;
442 }
443 
444 static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
445 {
446 	struct mptcp_pm_local locals[MPTCP_PM_ADDR_MAX];
447 	struct sock *sk = (struct sock *)msk;
448 	unsigned int add_addr_accept_max;
449 	struct mptcp_addr_info remote;
450 	unsigned int subflows_max;
451 	bool sf_created = false;
452 	int i, nr;
453 
454 	add_addr_accept_max = mptcp_pm_get_add_addr_accept_max(msk);
455 	subflows_max = mptcp_pm_get_subflows_max(msk);
456 
457 	pr_debug("accepted %d:%d remote family %d\n",
458 		 msk->pm.add_addr_accepted, add_addr_accept_max,
459 		 msk->pm.remote.family);
460 
461 	remote = msk->pm.remote;
462 	mptcp_pm_announce_addr(msk, &remote, true);
463 	mptcp_pm_addr_send_ack(msk);
464 
465 	if (lookup_subflow_by_daddr(&msk->conn_list, &remote))
466 		return;
467 
468 	/* pick id 0 port, if none is provided the remote address */
469 	if (!remote.port)
470 		remote.port = sk->sk_dport;
471 
472 	/* connect to the specified remote address, using whatever
473 	 * local address the routing configuration will pick.
474 	 */
475 	nr = fill_local_addresses_vec(msk, &remote, locals);
476 	if (nr == 0)
477 		return;
478 
479 	spin_unlock_bh(&msk->pm.lock);
480 	for (i = 0; i < nr; i++)
481 		if (__mptcp_subflow_connect(sk, &locals[i], &remote) == 0)
482 			sf_created = true;
483 	spin_lock_bh(&msk->pm.lock);
484 
485 	if (sf_created) {
486 		/* add_addr_accepted is not decr for ID 0 */
487 		if (remote.id)
488 			msk->pm.add_addr_accepted++;
489 		if (msk->pm.add_addr_accepted >= add_addr_accept_max ||
490 		    msk->pm.subflows >= subflows_max)
491 			WRITE_ONCE(msk->pm.accept_addr, false);
492 	}
493 }
494 
495 void mptcp_pm_nl_rm_addr(struct mptcp_sock *msk, u8 rm_id)
496 {
497 	if (rm_id && WARN_ON_ONCE(msk->pm.add_addr_accepted == 0)) {
498 		/* Note: if the subflow has been closed before, this
499 		 * add_addr_accepted counter will not be decremented.
500 		 */
501 		if (--msk->pm.add_addr_accepted < mptcp_pm_get_add_addr_accept_max(msk))
502 			WRITE_ONCE(msk->pm.accept_addr, true);
503 	}
504 }
505 
506 static bool address_use_port(struct mptcp_pm_addr_entry *entry)
507 {
508 	return (entry->flags &
509 		(MPTCP_PM_ADDR_FLAG_SIGNAL | MPTCP_PM_ADDR_FLAG_SUBFLOW)) ==
510 		MPTCP_PM_ADDR_FLAG_SIGNAL;
511 }
512 
513 /* caller must ensure the RCU grace period is already elapsed */
514 static void __mptcp_pm_release_addr_entry(struct mptcp_pm_addr_entry *entry)
515 {
516 	if (entry->lsk)
517 		sock_release(entry->lsk);
518 	kfree(entry);
519 }
520 
521 static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
522 					     struct mptcp_pm_addr_entry *entry,
523 					     bool needs_id, bool replace)
524 {
525 	struct mptcp_pm_addr_entry *cur, *del_entry = NULL;
526 	unsigned int addr_max;
527 	int ret = -EINVAL;
528 
529 	spin_lock_bh(&pernet->lock);
530 	/* to keep the code simple, don't do IDR-like allocation for address ID,
531 	 * just bail when we exceed limits
532 	 */
533 	if (pernet->next_id == MPTCP_PM_MAX_ADDR_ID)
534 		pernet->next_id = 1;
535 	if (pernet->addrs >= MPTCP_PM_ADDR_MAX) {
536 		ret = -ERANGE;
537 		goto out;
538 	}
539 	if (test_bit(entry->addr.id, pernet->id_bitmap)) {
540 		ret = -EBUSY;
541 		goto out;
542 	}
543 
544 	/* do not insert duplicate address, differentiate on port only
545 	 * singled addresses
546 	 */
547 	if (!address_use_port(entry))
548 		entry->addr.port = 0;
549 	list_for_each_entry(cur, &pernet->local_addr_list, list) {
550 		if (mptcp_addresses_equal(&cur->addr, &entry->addr,
551 					  cur->addr.port || entry->addr.port)) {
552 			/* allow replacing the exiting endpoint only if such
553 			 * endpoint is an implicit one and the user-space
554 			 * did not provide an endpoint id
555 			 */
556 			if (!(cur->flags & MPTCP_PM_ADDR_FLAG_IMPLICIT)) {
557 				ret = -EEXIST;
558 				goto out;
559 			}
560 			if (entry->addr.id)
561 				goto out;
562 
563 			/* allow callers that only need to look up the local
564 			 * addr's id to skip replacement. This allows them to
565 			 * avoid calling synchronize_rcu in the packet recv
566 			 * path.
567 			 */
568 			if (!replace) {
569 				kfree(entry);
570 				ret = cur->addr.id;
571 				goto out;
572 			}
573 
574 			pernet->addrs--;
575 			entry->addr.id = cur->addr.id;
576 			list_del_rcu(&cur->list);
577 			del_entry = cur;
578 			break;
579 		}
580 	}
581 
582 	if (!entry->addr.id && needs_id) {
583 find_next:
584 		entry->addr.id = find_next_zero_bit(pernet->id_bitmap,
585 						    MPTCP_PM_MAX_ADDR_ID + 1,
586 						    pernet->next_id);
587 		if (!entry->addr.id && pernet->next_id != 1) {
588 			pernet->next_id = 1;
589 			goto find_next;
590 		}
591 	}
592 
593 	if (!entry->addr.id && needs_id)
594 		goto out;
595 
596 	__set_bit(entry->addr.id, pernet->id_bitmap);
597 	if (entry->addr.id > pernet->next_id)
598 		pernet->next_id = entry->addr.id;
599 
600 	if (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL) {
601 		addr_max = pernet->add_addr_signal_max;
602 		WRITE_ONCE(pernet->add_addr_signal_max, addr_max + 1);
603 	}
604 	if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) {
605 		addr_max = pernet->local_addr_max;
606 		WRITE_ONCE(pernet->local_addr_max, addr_max + 1);
607 	}
608 
609 	pernet->addrs++;
610 	if (!entry->addr.port)
611 		list_add_tail_rcu(&entry->list, &pernet->local_addr_list);
612 	else
613 		list_add_rcu(&entry->list, &pernet->local_addr_list);
614 	ret = entry->addr.id;
615 
616 out:
617 	spin_unlock_bh(&pernet->lock);
618 
619 	/* just replaced an existing entry, free it */
620 	if (del_entry) {
621 		synchronize_rcu();
622 		__mptcp_pm_release_addr_entry(del_entry);
623 	}
624 	return ret;
625 }
626 
627 static struct lock_class_key mptcp_slock_keys[2];
628 static struct lock_class_key mptcp_keys[2];
629 
630 static int mptcp_pm_nl_create_listen_socket(struct sock *sk,
631 					    struct mptcp_pm_addr_entry *entry)
632 {
633 	bool is_ipv6 = sk->sk_family == AF_INET6;
634 	int addrlen = sizeof(struct sockaddr_in);
635 	struct sockaddr_storage addr;
636 	struct sock *newsk, *ssk;
637 	int backlog = 1024;
638 	int err;
639 
640 	err = sock_create_kern(sock_net(sk), entry->addr.family,
641 			       SOCK_STREAM, IPPROTO_MPTCP, &entry->lsk);
642 	if (err)
643 		return err;
644 
645 	newsk = entry->lsk->sk;
646 	if (!newsk)
647 		return -EINVAL;
648 
649 	/* The subflow socket lock is acquired in a nested to the msk one
650 	 * in several places, even by the TCP stack, and this msk is a kernel
651 	 * socket: lockdep complains. Instead of propagating the _nested
652 	 * modifiers in several places, re-init the lock class for the msk
653 	 * socket to an mptcp specific one.
654 	 */
655 	sock_lock_init_class_and_name(newsk,
656 				      is_ipv6 ? "mlock-AF_INET6" : "mlock-AF_INET",
657 				      &mptcp_slock_keys[is_ipv6],
658 				      is_ipv6 ? "msk_lock-AF_INET6" : "msk_lock-AF_INET",
659 				      &mptcp_keys[is_ipv6]);
660 
661 	lock_sock(newsk);
662 	ssk = __mptcp_nmpc_sk(mptcp_sk(newsk));
663 	release_sock(newsk);
664 	if (IS_ERR(ssk))
665 		return PTR_ERR(ssk);
666 
667 	mptcp_info2sockaddr(&entry->addr, &addr, entry->addr.family);
668 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
669 	if (entry->addr.family == AF_INET6)
670 		addrlen = sizeof(struct sockaddr_in6);
671 #endif
672 	if (ssk->sk_family == AF_INET)
673 		err = inet_bind_sk(ssk, (struct sockaddr *)&addr, addrlen);
674 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
675 	else if (ssk->sk_family == AF_INET6)
676 		err = inet6_bind_sk(ssk, (struct sockaddr *)&addr, addrlen);
677 #endif
678 	if (err)
679 		return err;
680 
681 	/* We don't use mptcp_set_state() here because it needs to be called
682 	 * under the msk socket lock. For the moment, that will not bring
683 	 * anything more than only calling inet_sk_state_store(), because the
684 	 * old status is known (TCP_CLOSE).
685 	 */
686 	inet_sk_state_store(newsk, TCP_LISTEN);
687 	lock_sock(ssk);
688 	WRITE_ONCE(mptcp_subflow_ctx(ssk)->pm_listener, true);
689 	err = __inet_listen_sk(ssk, backlog);
690 	if (!err)
691 		mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CREATED);
692 	release_sock(ssk);
693 	return err;
694 }
695 
696 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk,
697 			     struct mptcp_pm_addr_entry *skc)
698 {
699 	struct mptcp_pm_addr_entry *entry;
700 	struct pm_nl_pernet *pernet;
701 	int ret;
702 
703 	pernet = pm_nl_get_pernet_from_msk(msk);
704 
705 	rcu_read_lock();
706 	entry = __lookup_addr(pernet, &skc->addr);
707 	ret = entry ? entry->addr.id : -1;
708 	rcu_read_unlock();
709 	if (ret >= 0)
710 		return ret;
711 
712 	/* address not found, add to local list */
713 	entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
714 	if (!entry)
715 		return -ENOMEM;
716 
717 	*entry = *skc;
718 	entry->addr.port = 0;
719 	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry, true, false);
720 	if (ret < 0)
721 		kfree(entry);
722 
723 	return ret;
724 }
725 
726 bool mptcp_pm_nl_is_backup(struct mptcp_sock *msk, struct mptcp_addr_info *skc)
727 {
728 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
729 	struct mptcp_pm_addr_entry *entry;
730 	bool backup;
731 
732 	rcu_read_lock();
733 	entry = __lookup_addr(pernet, skc);
734 	backup = entry && !!(entry->flags & MPTCP_PM_ADDR_FLAG_BACKUP);
735 	rcu_read_unlock();
736 
737 	return backup;
738 }
739 
740 static int mptcp_nl_add_subflow_or_signal_addr(struct net *net,
741 					       struct mptcp_addr_info *addr)
742 {
743 	struct mptcp_sock *msk;
744 	long s_slot = 0, s_num = 0;
745 
746 	while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
747 		struct sock *sk = (struct sock *)msk;
748 		struct mptcp_addr_info mpc_addr;
749 
750 		if (!READ_ONCE(msk->fully_established) ||
751 		    mptcp_pm_is_userspace(msk))
752 			goto next;
753 
754 		/* if the endp linked to the init sf is re-added with a != ID */
755 		mptcp_local_address((struct sock_common *)msk, &mpc_addr);
756 
757 		lock_sock(sk);
758 		spin_lock_bh(&msk->pm.lock);
759 		if (mptcp_addresses_equal(addr, &mpc_addr, addr->port))
760 			msk->mpc_endpoint_id = addr->id;
761 		mptcp_pm_create_subflow_or_signal_addr(msk);
762 		spin_unlock_bh(&msk->pm.lock);
763 		release_sock(sk);
764 
765 next:
766 		sock_put(sk);
767 		cond_resched();
768 	}
769 
770 	return 0;
771 }
772 
773 static bool mptcp_pm_has_addr_attr_id(const struct nlattr *attr,
774 				      struct genl_info *info)
775 {
776 	struct nlattr *tb[MPTCP_PM_ADDR_ATTR_MAX + 1];
777 
778 	if (!nla_parse_nested_deprecated(tb, MPTCP_PM_ADDR_ATTR_MAX, attr,
779 					 mptcp_pm_address_nl_policy, info->extack) &&
780 	    tb[MPTCP_PM_ADDR_ATTR_ID])
781 		return true;
782 	return false;
783 }
784 
785 /* Add an MPTCP endpoint */
786 int mptcp_pm_nl_add_addr_doit(struct sk_buff *skb, struct genl_info *info)
787 {
788 	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
789 	struct mptcp_pm_addr_entry addr, *entry;
790 	struct nlattr *attr;
791 	int ret;
792 
793 	if (GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ENDPOINT_ADDR))
794 		return -EINVAL;
795 
796 	attr = info->attrs[MPTCP_PM_ENDPOINT_ADDR];
797 	ret = mptcp_pm_parse_entry(attr, info, true, &addr);
798 	if (ret < 0)
799 		return ret;
800 
801 	if (addr.addr.port && !address_use_port(&addr)) {
802 		NL_SET_ERR_MSG_ATTR(info->extack, attr,
803 				    "flags must have signal and not subflow when using port");
804 		return -EINVAL;
805 	}
806 
807 	if (addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL &&
808 	    addr.flags & MPTCP_PM_ADDR_FLAG_FULLMESH) {
809 		NL_SET_ERR_MSG_ATTR(info->extack, attr,
810 				    "flags mustn't have both signal and fullmesh");
811 		return -EINVAL;
812 	}
813 
814 	if (addr.flags & MPTCP_PM_ADDR_FLAG_IMPLICIT) {
815 		NL_SET_ERR_MSG_ATTR(info->extack, attr,
816 				    "can't create IMPLICIT endpoint");
817 		return -EINVAL;
818 	}
819 
820 	entry = kzalloc(sizeof(*entry), GFP_KERNEL_ACCOUNT);
821 	if (!entry) {
822 		GENL_SET_ERR_MSG(info, "can't allocate addr");
823 		return -ENOMEM;
824 	}
825 
826 	*entry = addr;
827 	if (entry->addr.port) {
828 		ret = mptcp_pm_nl_create_listen_socket(skb->sk, entry);
829 		if (ret) {
830 			GENL_SET_ERR_MSG_FMT(info, "create listen socket error: %d", ret);
831 			goto out_free;
832 		}
833 	}
834 	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry,
835 						!mptcp_pm_has_addr_attr_id(attr, info),
836 						true);
837 	if (ret < 0) {
838 		GENL_SET_ERR_MSG_FMT(info, "too many addresses or duplicate one: %d", ret);
839 		goto out_free;
840 	}
841 
842 	mptcp_nl_add_subflow_or_signal_addr(sock_net(skb->sk), &entry->addr);
843 	return 0;
844 
845 out_free:
846 	__mptcp_pm_release_addr_entry(entry);
847 	return ret;
848 }
849 
850 static u8 mptcp_endp_get_local_id(struct mptcp_sock *msk,
851 				  const struct mptcp_addr_info *addr)
852 {
853 	return msk->mpc_endpoint_id == addr->id ? 0 : addr->id;
854 }
855 
856 static bool mptcp_pm_remove_anno_addr(struct mptcp_sock *msk,
857 				      const struct mptcp_addr_info *addr,
858 				      bool force)
859 {
860 	struct mptcp_rm_list list = { .nr = 0 };
861 	bool ret;
862 
863 	list.ids[list.nr++] = mptcp_endp_get_local_id(msk, addr);
864 
865 	ret = mptcp_remove_anno_list_by_saddr(msk, addr);
866 	if (ret || force) {
867 		spin_lock_bh(&msk->pm.lock);
868 		if (ret) {
869 			__set_bit(addr->id, msk->pm.id_avail_bitmap);
870 			msk->pm.add_addr_signaled--;
871 		}
872 		mptcp_pm_remove_addr(msk, &list);
873 		spin_unlock_bh(&msk->pm.lock);
874 	}
875 	return ret;
876 }
877 
878 static void __mark_subflow_endp_available(struct mptcp_sock *msk, u8 id)
879 {
880 	/* If it was marked as used, and not ID 0, decrement local_addr_used */
881 	if (!__test_and_set_bit(id ? : msk->mpc_endpoint_id, msk->pm.id_avail_bitmap) &&
882 	    id && !WARN_ON_ONCE(msk->pm.local_addr_used == 0))
883 		msk->pm.local_addr_used--;
884 }
885 
886 static int mptcp_nl_remove_subflow_and_signal_addr(struct net *net,
887 						   const struct mptcp_pm_addr_entry *entry)
888 {
889 	const struct mptcp_addr_info *addr = &entry->addr;
890 	struct mptcp_rm_list list = { .nr = 1 };
891 	long s_slot = 0, s_num = 0;
892 	struct mptcp_sock *msk;
893 
894 	pr_debug("remove_id=%d\n", addr->id);
895 
896 	while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
897 		struct sock *sk = (struct sock *)msk;
898 		bool remove_subflow;
899 
900 		if (mptcp_pm_is_userspace(msk))
901 			goto next;
902 
903 		lock_sock(sk);
904 		remove_subflow = mptcp_lookup_subflow_by_saddr(&msk->conn_list, addr);
905 		mptcp_pm_remove_anno_addr(msk, addr, remove_subflow &&
906 					  !(entry->flags & MPTCP_PM_ADDR_FLAG_IMPLICIT));
907 
908 		list.ids[0] = mptcp_endp_get_local_id(msk, addr);
909 		if (remove_subflow) {
910 			spin_lock_bh(&msk->pm.lock);
911 			mptcp_pm_rm_subflow(msk, &list);
912 			spin_unlock_bh(&msk->pm.lock);
913 		}
914 
915 		if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) {
916 			spin_lock_bh(&msk->pm.lock);
917 			__mark_subflow_endp_available(msk, list.ids[0]);
918 			spin_unlock_bh(&msk->pm.lock);
919 		}
920 
921 		if (msk->mpc_endpoint_id == entry->addr.id)
922 			msk->mpc_endpoint_id = 0;
923 		release_sock(sk);
924 
925 next:
926 		sock_put(sk);
927 		cond_resched();
928 	}
929 
930 	return 0;
931 }
932 
933 static int mptcp_nl_remove_id_zero_address(struct net *net,
934 					   struct mptcp_addr_info *addr)
935 {
936 	struct mptcp_rm_list list = { .nr = 0 };
937 	long s_slot = 0, s_num = 0;
938 	struct mptcp_sock *msk;
939 
940 	list.ids[list.nr++] = 0;
941 
942 	while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
943 		struct sock *sk = (struct sock *)msk;
944 		struct mptcp_addr_info msk_local;
945 
946 		if (list_empty(&msk->conn_list) || mptcp_pm_is_userspace(msk))
947 			goto next;
948 
949 		mptcp_local_address((struct sock_common *)msk, &msk_local);
950 		if (!mptcp_addresses_equal(&msk_local, addr, addr->port))
951 			goto next;
952 
953 		lock_sock(sk);
954 		spin_lock_bh(&msk->pm.lock);
955 		mptcp_pm_remove_addr(msk, &list);
956 		mptcp_pm_rm_subflow(msk, &list);
957 		__mark_subflow_endp_available(msk, 0);
958 		spin_unlock_bh(&msk->pm.lock);
959 		release_sock(sk);
960 
961 next:
962 		sock_put(sk);
963 		cond_resched();
964 	}
965 
966 	return 0;
967 }
968 
969 /* Remove an MPTCP endpoint */
970 int mptcp_pm_nl_del_addr_doit(struct sk_buff *skb, struct genl_info *info)
971 {
972 	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
973 	struct mptcp_pm_addr_entry addr, *entry;
974 	unsigned int addr_max;
975 	struct nlattr *attr;
976 	int ret;
977 
978 	if (GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ENDPOINT_ADDR))
979 		return -EINVAL;
980 
981 	attr = info->attrs[MPTCP_PM_ENDPOINT_ADDR];
982 	ret = mptcp_pm_parse_entry(attr, info, false, &addr);
983 	if (ret < 0)
984 		return ret;
985 
986 	/* the zero id address is special: the first address used by the msk
987 	 * always gets such an id, so different subflows can have different zero
988 	 * id addresses. Additionally zero id is not accounted for in id_bitmap.
989 	 * Let's use an 'mptcp_rm_list' instead of the common remove code.
990 	 */
991 	if (addr.addr.id == 0)
992 		return mptcp_nl_remove_id_zero_address(sock_net(skb->sk), &addr.addr);
993 
994 	spin_lock_bh(&pernet->lock);
995 	entry = __lookup_addr_by_id(pernet, addr.addr.id);
996 	if (!entry) {
997 		NL_SET_ERR_MSG_ATTR(info->extack, attr, "address not found");
998 		spin_unlock_bh(&pernet->lock);
999 		return -EINVAL;
1000 	}
1001 	if (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL) {
1002 		addr_max = pernet->add_addr_signal_max;
1003 		WRITE_ONCE(pernet->add_addr_signal_max, addr_max - 1);
1004 	}
1005 	if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) {
1006 		addr_max = pernet->local_addr_max;
1007 		WRITE_ONCE(pernet->local_addr_max, addr_max - 1);
1008 	}
1009 
1010 	pernet->addrs--;
1011 	list_del_rcu(&entry->list);
1012 	__clear_bit(entry->addr.id, pernet->id_bitmap);
1013 	spin_unlock_bh(&pernet->lock);
1014 
1015 	mptcp_nl_remove_subflow_and_signal_addr(sock_net(skb->sk), entry);
1016 	synchronize_rcu();
1017 	__mptcp_pm_release_addr_entry(entry);
1018 
1019 	return ret;
1020 }
1021 
1022 static void mptcp_pm_flush_addrs_and_subflows(struct mptcp_sock *msk,
1023 					      struct list_head *rm_list)
1024 {
1025 	struct mptcp_rm_list alist = { .nr = 0 }, slist = { .nr = 0 };
1026 	struct mptcp_pm_addr_entry *entry;
1027 
1028 	list_for_each_entry(entry, rm_list, list) {
1029 		if (slist.nr < MPTCP_RM_IDS_MAX &&
1030 		    mptcp_lookup_subflow_by_saddr(&msk->conn_list, &entry->addr))
1031 			slist.ids[slist.nr++] = mptcp_endp_get_local_id(msk, &entry->addr);
1032 
1033 		if (alist.nr < MPTCP_RM_IDS_MAX &&
1034 		    mptcp_remove_anno_list_by_saddr(msk, &entry->addr))
1035 			alist.ids[alist.nr++] = mptcp_endp_get_local_id(msk, &entry->addr);
1036 	}
1037 
1038 	spin_lock_bh(&msk->pm.lock);
1039 	if (alist.nr) {
1040 		msk->pm.add_addr_signaled -= alist.nr;
1041 		mptcp_pm_remove_addr(msk, &alist);
1042 	}
1043 	if (slist.nr)
1044 		mptcp_pm_rm_subflow(msk, &slist);
1045 	/* Reset counters: maybe some subflows have been removed before */
1046 	bitmap_fill(msk->pm.id_avail_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
1047 	msk->pm.local_addr_used = 0;
1048 	spin_unlock_bh(&msk->pm.lock);
1049 }
1050 
1051 static void mptcp_nl_flush_addrs_list(struct net *net,
1052 				      struct list_head *rm_list)
1053 {
1054 	long s_slot = 0, s_num = 0;
1055 	struct mptcp_sock *msk;
1056 
1057 	if (list_empty(rm_list))
1058 		return;
1059 
1060 	while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
1061 		struct sock *sk = (struct sock *)msk;
1062 
1063 		if (!mptcp_pm_is_userspace(msk)) {
1064 			lock_sock(sk);
1065 			mptcp_pm_flush_addrs_and_subflows(msk, rm_list);
1066 			release_sock(sk);
1067 		}
1068 
1069 		sock_put(sk);
1070 		cond_resched();
1071 	}
1072 }
1073 
1074 /* caller must ensure the RCU grace period is already elapsed */
1075 static void __flush_addrs(struct list_head *list)
1076 {
1077 	while (!list_empty(list)) {
1078 		struct mptcp_pm_addr_entry *cur;
1079 
1080 		cur = list_entry(list->next,
1081 				 struct mptcp_pm_addr_entry, list);
1082 		list_del_rcu(&cur->list);
1083 		__mptcp_pm_release_addr_entry(cur);
1084 	}
1085 }
1086 
1087 static void __reset_counters(struct pm_nl_pernet *pernet)
1088 {
1089 	WRITE_ONCE(pernet->add_addr_signal_max, 0);
1090 	WRITE_ONCE(pernet->add_addr_accept_max, 0);
1091 	WRITE_ONCE(pernet->local_addr_max, 0);
1092 	pernet->addrs = 0;
1093 }
1094 
1095 int mptcp_pm_nl_flush_addrs_doit(struct sk_buff *skb, struct genl_info *info)
1096 {
1097 	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1098 	LIST_HEAD(free_list);
1099 
1100 	spin_lock_bh(&pernet->lock);
1101 	list_splice_init(&pernet->local_addr_list, &free_list);
1102 	__reset_counters(pernet);
1103 	pernet->next_id = 1;
1104 	bitmap_zero(pernet->id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
1105 	spin_unlock_bh(&pernet->lock);
1106 	mptcp_nl_flush_addrs_list(sock_net(skb->sk), &free_list);
1107 	synchronize_rcu();
1108 	__flush_addrs(&free_list);
1109 	return 0;
1110 }
1111 
1112 int mptcp_pm_nl_get_addr(u8 id, struct mptcp_pm_addr_entry *addr,
1113 			 struct genl_info *info)
1114 {
1115 	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1116 	struct mptcp_pm_addr_entry *entry;
1117 	int ret = -EINVAL;
1118 
1119 	rcu_read_lock();
1120 	entry = __lookup_addr_by_id(pernet, id);
1121 	if (entry) {
1122 		*addr = *entry;
1123 		ret = 0;
1124 	}
1125 	rcu_read_unlock();
1126 
1127 	return ret;
1128 }
1129 
1130 int mptcp_pm_nl_dump_addr(struct sk_buff *msg,
1131 			  struct netlink_callback *cb)
1132 {
1133 	struct net *net = sock_net(msg->sk);
1134 	struct mptcp_pm_addr_entry *entry;
1135 	struct pm_nl_pernet *pernet;
1136 	int id = cb->args[0];
1137 	int i;
1138 
1139 	pernet = pm_nl_get_pernet(net);
1140 
1141 	rcu_read_lock();
1142 	for (i = id; i < MPTCP_PM_MAX_ADDR_ID + 1; i++) {
1143 		if (test_bit(i, pernet->id_bitmap)) {
1144 			entry = __lookup_addr_by_id(pernet, i);
1145 			if (!entry)
1146 				break;
1147 
1148 			if (entry->addr.id <= id)
1149 				continue;
1150 
1151 			if (mptcp_pm_genl_fill_addr(msg, cb, entry) < 0)
1152 				break;
1153 
1154 			id = entry->addr.id;
1155 		}
1156 	}
1157 	rcu_read_unlock();
1158 
1159 	cb->args[0] = id;
1160 	return msg->len;
1161 }
1162 
1163 static int parse_limit(struct genl_info *info, int id, unsigned int *limit)
1164 {
1165 	struct nlattr *attr = info->attrs[id];
1166 
1167 	if (!attr)
1168 		return 0;
1169 
1170 	*limit = nla_get_u32(attr);
1171 	if (*limit > MPTCP_PM_ADDR_MAX) {
1172 		NL_SET_ERR_MSG_ATTR_FMT(info->extack, attr,
1173 					"limit greater than maximum (%u)",
1174 					MPTCP_PM_ADDR_MAX);
1175 		return -EINVAL;
1176 	}
1177 	return 0;
1178 }
1179 
1180 int mptcp_pm_nl_set_limits_doit(struct sk_buff *skb, struct genl_info *info)
1181 {
1182 	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1183 	unsigned int rcv_addrs, subflows;
1184 	int ret;
1185 
1186 	spin_lock_bh(&pernet->lock);
1187 	rcv_addrs = pernet->add_addr_accept_max;
1188 	ret = parse_limit(info, MPTCP_PM_ATTR_RCV_ADD_ADDRS, &rcv_addrs);
1189 	if (ret)
1190 		goto unlock;
1191 
1192 	subflows = pernet->subflows_max;
1193 	ret = parse_limit(info, MPTCP_PM_ATTR_SUBFLOWS, &subflows);
1194 	if (ret)
1195 		goto unlock;
1196 
1197 	WRITE_ONCE(pernet->add_addr_accept_max, rcv_addrs);
1198 	WRITE_ONCE(pernet->subflows_max, subflows);
1199 
1200 unlock:
1201 	spin_unlock_bh(&pernet->lock);
1202 	return ret;
1203 }
1204 
1205 int mptcp_pm_nl_get_limits_doit(struct sk_buff *skb, struct genl_info *info)
1206 {
1207 	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1208 	struct sk_buff *msg;
1209 	void *reply;
1210 
1211 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1212 	if (!msg)
1213 		return -ENOMEM;
1214 
1215 	reply = genlmsg_put_reply(msg, info, &mptcp_genl_family, 0,
1216 				  MPTCP_PM_CMD_GET_LIMITS);
1217 	if (!reply)
1218 		goto fail;
1219 
1220 	if (nla_put_u32(msg, MPTCP_PM_ATTR_RCV_ADD_ADDRS,
1221 			READ_ONCE(pernet->add_addr_accept_max)))
1222 		goto fail;
1223 
1224 	if (nla_put_u32(msg, MPTCP_PM_ATTR_SUBFLOWS,
1225 			READ_ONCE(pernet->subflows_max)))
1226 		goto fail;
1227 
1228 	genlmsg_end(msg, reply);
1229 	return genlmsg_reply(msg, info);
1230 
1231 fail:
1232 	GENL_SET_ERR_MSG(info, "not enough space in Netlink message");
1233 	nlmsg_free(msg);
1234 	return -EMSGSIZE;
1235 }
1236 
1237 static void mptcp_pm_nl_fullmesh(struct mptcp_sock *msk,
1238 				 struct mptcp_addr_info *addr)
1239 {
1240 	struct mptcp_rm_list list = { .nr = 0 };
1241 
1242 	list.ids[list.nr++] = mptcp_endp_get_local_id(msk, addr);
1243 
1244 	spin_lock_bh(&msk->pm.lock);
1245 	mptcp_pm_rm_subflow(msk, &list);
1246 	__mark_subflow_endp_available(msk, list.ids[0]);
1247 	mptcp_pm_create_subflow_or_signal_addr(msk);
1248 	spin_unlock_bh(&msk->pm.lock);
1249 }
1250 
1251 static void mptcp_pm_nl_set_flags_all(struct net *net,
1252 				      struct mptcp_pm_addr_entry *local,
1253 				      u8 changed)
1254 {
1255 	u8 is_subflow = !!(local->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW);
1256 	u8 bkup = !!(local->flags & MPTCP_PM_ADDR_FLAG_BACKUP);
1257 	long s_slot = 0, s_num = 0;
1258 	struct mptcp_sock *msk;
1259 
1260 	if (changed == MPTCP_PM_ADDR_FLAG_FULLMESH && !is_subflow)
1261 		return;
1262 
1263 	while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
1264 		struct sock *sk = (struct sock *)msk;
1265 
1266 		if (list_empty(&msk->conn_list) || mptcp_pm_is_userspace(msk))
1267 			goto next;
1268 
1269 		lock_sock(sk);
1270 		if (changed & MPTCP_PM_ADDR_FLAG_BACKUP)
1271 			mptcp_pm_mp_prio_send_ack(msk, &local->addr, NULL, bkup);
1272 		/* Subflows will only be recreated if the SUBFLOW flag is set */
1273 		if (is_subflow && (changed & MPTCP_PM_ADDR_FLAG_FULLMESH))
1274 			mptcp_pm_nl_fullmesh(msk, &local->addr);
1275 		release_sock(sk);
1276 
1277 next:
1278 		sock_put(sk);
1279 		cond_resched();
1280 	}
1281 }
1282 
1283 int mptcp_pm_nl_set_flags(struct mptcp_pm_addr_entry *local,
1284 			  struct genl_info *info)
1285 {
1286 	struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
1287 	u8 changed, mask = MPTCP_PM_ADDR_FLAG_BACKUP |
1288 			   MPTCP_PM_ADDR_FLAG_FULLMESH;
1289 	struct net *net = genl_info_net(info);
1290 	struct mptcp_pm_addr_entry *entry;
1291 	struct pm_nl_pernet *pernet;
1292 	u8 lookup_by_id = 0;
1293 
1294 	pernet = pm_nl_get_pernet(net);
1295 
1296 	if (local->addr.family == AF_UNSPEC) {
1297 		lookup_by_id = 1;
1298 		if (!local->addr.id) {
1299 			NL_SET_ERR_MSG_ATTR(info->extack, attr,
1300 					    "missing address ID");
1301 			return -EOPNOTSUPP;
1302 		}
1303 	}
1304 
1305 	spin_lock_bh(&pernet->lock);
1306 	entry = lookup_by_id ? __lookup_addr_by_id(pernet, local->addr.id) :
1307 			       __lookup_addr(pernet, &local->addr);
1308 	if (!entry) {
1309 		spin_unlock_bh(&pernet->lock);
1310 		NL_SET_ERR_MSG_ATTR(info->extack, attr, "address not found");
1311 		return -EINVAL;
1312 	}
1313 	if ((local->flags & MPTCP_PM_ADDR_FLAG_FULLMESH) &&
1314 	    (entry->flags & (MPTCP_PM_ADDR_FLAG_SIGNAL |
1315 			     MPTCP_PM_ADDR_FLAG_IMPLICIT))) {
1316 		spin_unlock_bh(&pernet->lock);
1317 		NL_SET_ERR_MSG_ATTR(info->extack, attr, "invalid addr flags");
1318 		return -EINVAL;
1319 	}
1320 
1321 	changed = (local->flags ^ entry->flags) & mask;
1322 	entry->flags = (entry->flags & ~mask) | (local->flags & mask);
1323 	*local = *entry;
1324 	spin_unlock_bh(&pernet->lock);
1325 
1326 	mptcp_pm_nl_set_flags_all(net, local, changed);
1327 	return 0;
1328 }
1329 
1330 bool mptcp_pm_nl_check_work_pending(struct mptcp_sock *msk)
1331 {
1332 	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
1333 
1334 	if (msk->pm.subflows == mptcp_pm_get_subflows_max(msk) ||
1335 	    (find_next_and_bit(pernet->id_bitmap, msk->pm.id_avail_bitmap,
1336 			       MPTCP_PM_MAX_ADDR_ID + 1, 0) == MPTCP_PM_MAX_ADDR_ID + 1)) {
1337 		WRITE_ONCE(msk->pm.work_pending, false);
1338 		return false;
1339 	}
1340 	return true;
1341 }
1342 
1343 /* Called under PM lock */
1344 void __mptcp_pm_kernel_worker(struct mptcp_sock *msk)
1345 {
1346 	struct mptcp_pm_data *pm = &msk->pm;
1347 
1348 	if (pm->status & BIT(MPTCP_PM_ADD_ADDR_RECEIVED)) {
1349 		pm->status &= ~BIT(MPTCP_PM_ADD_ADDR_RECEIVED);
1350 		mptcp_pm_nl_add_addr_received(msk);
1351 	}
1352 	if (pm->status & BIT(MPTCP_PM_ESTABLISHED)) {
1353 		pm->status &= ~BIT(MPTCP_PM_ESTABLISHED);
1354 		mptcp_pm_nl_fully_established(msk);
1355 	}
1356 	if (pm->status & BIT(MPTCP_PM_SUBFLOW_ESTABLISHED)) {
1357 		pm->status &= ~BIT(MPTCP_PM_SUBFLOW_ESTABLISHED);
1358 		mptcp_pm_nl_subflow_established(msk);
1359 	}
1360 }
1361 
1362 static int __net_init pm_nl_init_net(struct net *net)
1363 {
1364 	struct pm_nl_pernet *pernet = pm_nl_get_pernet(net);
1365 
1366 	INIT_LIST_HEAD_RCU(&pernet->local_addr_list);
1367 
1368 	/* Cit. 2 subflows ought to be enough for anybody. */
1369 	pernet->subflows_max = 2;
1370 	pernet->next_id = 1;
1371 	pernet->stale_loss_cnt = 4;
1372 	spin_lock_init(&pernet->lock);
1373 
1374 	/* No need to initialize other pernet fields, the struct is zeroed at
1375 	 * allocation time.
1376 	 */
1377 
1378 	return 0;
1379 }
1380 
1381 static void __net_exit pm_nl_exit_net(struct list_head *net_list)
1382 {
1383 	struct net *net;
1384 
1385 	list_for_each_entry(net, net_list, exit_list) {
1386 		struct pm_nl_pernet *pernet = pm_nl_get_pernet(net);
1387 
1388 		/* net is removed from namespace list, can't race with
1389 		 * other modifiers, also netns core already waited for a
1390 		 * RCU grace period.
1391 		 */
1392 		__flush_addrs(&pernet->local_addr_list);
1393 	}
1394 }
1395 
1396 static struct pernet_operations mptcp_pm_pernet_ops = {
1397 	.init = pm_nl_init_net,
1398 	.exit_batch = pm_nl_exit_net,
1399 	.id = &pm_nl_pernet_id,
1400 	.size = sizeof(struct pm_nl_pernet),
1401 };
1402 
1403 void __init mptcp_pm_nl_init(void)
1404 {
1405 	if (register_pernet_subsys(&mptcp_pm_pernet_ops) < 0)
1406 		panic("Failed to register MPTCP PM pernet subsystem.\n");
1407 
1408 	if (genl_register_family(&mptcp_genl_family))
1409 		panic("Failed to register MPTCP PM netlink family\n");
1410 }
1411