1 // SPDX-License-Identifier: GPL-2.0
2 /* Multipath TCP
3 *
4 * Copyright (c) 2019, Intel Corporation.
5 */
6 #define pr_fmt(fmt) "MPTCP: " fmt
7
8 #include <linux/kernel.h>
9 #include <net/mptcp.h>
10 #include "protocol.h"
11
12 #include "mib.h"
13
14 /* path manager command handlers */
15
16 int mptcp_pm_announce_addr(struct mptcp_sock *msk,
17 const struct mptcp_addr_info *addr,
18 bool echo)
19 {
20 u8 add_addr = READ_ONCE(msk->pm.addr_signal);
21
22 pr_debug("msk=%p, local_id=%d, echo=%d", msk, addr->id, echo);
23
24 lockdep_assert_held(&msk->pm.lock);
25
26 if (add_addr &
27 (echo ? BIT(MPTCP_ADD_ADDR_ECHO) : BIT(MPTCP_ADD_ADDR_SIGNAL))) {
28 MPTCP_INC_STATS(sock_net((struct sock *)msk),
29 echo ? MPTCP_MIB_ECHOADDTXDROP : MPTCP_MIB_ADDADDRTXDROP);
30 return -EINVAL;
31 }
32
33 if (echo) {
34 msk->pm.remote = *addr;
35 add_addr |= BIT(MPTCP_ADD_ADDR_ECHO);
36 } else {
37 msk->pm.local = *addr;
38 add_addr |= BIT(MPTCP_ADD_ADDR_SIGNAL);
39 }
40 WRITE_ONCE(msk->pm.addr_signal, add_addr);
41 return 0;
42 }
43
44 int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list)
45 {
46 u8 rm_addr = READ_ONCE(msk->pm.addr_signal);
47
48 pr_debug("msk=%p, rm_list_nr=%d", msk, rm_list->nr);
49
50 if (rm_addr) {
51 MPTCP_ADD_STATS(sock_net((struct sock *)msk),
52 MPTCP_MIB_RMADDRTXDROP, rm_list->nr);
53 return -EINVAL;
54 }
55
56 msk->pm.rm_list_tx = *rm_list;
57 rm_addr |= BIT(MPTCP_RM_ADDR_SIGNAL);
58 WRITE_ONCE(msk->pm.addr_signal, rm_addr);
59 mptcp_pm_nl_addr_send_ack(msk);
60 return 0;
61 }
62
63 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list)
64 {
65 pr_debug("msk=%p, rm_list_nr=%d", msk, rm_list->nr);
66
67 spin_lock_bh(&msk->pm.lock);
68 mptcp_pm_nl_rm_subflow_received(msk, rm_list);
69 spin_unlock_bh(&msk->pm.lock);
70 return 0;
71 }
72
73 /* path manager event handlers */
74
75 void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int server_side)
76 {
77 struct mptcp_pm_data *pm = &msk->pm;
78
79 pr_debug("msk=%p, token=%u side=%d", msk, READ_ONCE(msk->token), server_side);
80
81 WRITE_ONCE(pm->server_side, server_side);
82 mptcp_event(MPTCP_EVENT_CREATED, msk, ssk, GFP_ATOMIC);
83 }
84
85 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk)
86 {
87 struct mptcp_pm_data *pm = &msk->pm;
88 unsigned int subflows_max;
89 int ret = 0;
90
91 if (mptcp_pm_is_userspace(msk)) {
92 if (mptcp_userspace_pm_active(msk)) {
93 spin_lock_bh(&pm->lock);
94 pm->subflows++;
95 spin_unlock_bh(&pm->lock);
96 return true;
97 }
98 return false;
99 }
100
101 subflows_max = mptcp_pm_get_subflows_max(msk);
102
103 pr_debug("msk=%p subflows=%d max=%d allow=%d", msk, pm->subflows,
104 subflows_max, READ_ONCE(pm->accept_subflow));
105
106 /* try to avoid acquiring the lock below */
107 if (!READ_ONCE(pm->accept_subflow))
108 return false;
109
110 spin_lock_bh(&pm->lock);
111 if (READ_ONCE(pm->accept_subflow)) {
112 ret = pm->subflows < subflows_max;
113 if (ret && ++pm->subflows == subflows_max)
114 WRITE_ONCE(pm->accept_subflow, false);
115 }
116 spin_unlock_bh(&pm->lock);
117
118 return ret;
119 }
120
121 /* return true if the new status bit is currently cleared, that is, this event
122 * can be server, eventually by an already scheduled work
123 */
124 static bool mptcp_pm_schedule_work(struct mptcp_sock *msk,
125 enum mptcp_pm_status new_status)
126 {
127 pr_debug("msk=%p status=%x new=%lx", msk, msk->pm.status,
128 BIT(new_status));
129 if (msk->pm.status & BIT(new_status))
130 return false;
131
132 msk->pm.status |= BIT(new_status);
133 mptcp_schedule_work((struct sock *)msk);
134 return true;
135 }
136
137 void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock *ssk)
138 {
139 struct mptcp_pm_data *pm = &msk->pm;
140 bool announce = false;
141
142 pr_debug("msk=%p", msk);
143
144 spin_lock_bh(&pm->lock);
145
146 /* mptcp_pm_fully_established() can be invoked by multiple
147 * racing paths - accept() and check_fully_established()
148 * be sure to serve this event only once.
149 */
150 if (READ_ONCE(pm->work_pending) &&
151 !(msk->pm.status & BIT(MPTCP_PM_ALREADY_ESTABLISHED)))
152 mptcp_pm_schedule_work(msk, MPTCP_PM_ESTABLISHED);
153
154 if ((msk->pm.status & BIT(MPTCP_PM_ALREADY_ESTABLISHED)) == 0)
155 announce = true;
156
157 msk->pm.status |= BIT(MPTCP_PM_ALREADY_ESTABLISHED);
158 spin_unlock_bh(&pm->lock);
159
160 if (announce)
161 mptcp_event(MPTCP_EVENT_ESTABLISHED, msk, ssk, GFP_ATOMIC);
162 }
163
164 void mptcp_pm_connection_closed(struct mptcp_sock *msk)
165 {
166 pr_debug("msk=%p", msk);
167 }
168
169 void mptcp_pm_subflow_established(struct mptcp_sock *msk)
170 {
171 struct mptcp_pm_data *pm = &msk->pm;
172
173 pr_debug("msk=%p", msk);
174
175 if (!READ_ONCE(pm->work_pending))
176 return;
177
178 spin_lock_bh(&pm->lock);
179
180 if (READ_ONCE(pm->work_pending))
181 mptcp_pm_schedule_work(msk, MPTCP_PM_SUBFLOW_ESTABLISHED);
182
183 spin_unlock_bh(&pm->lock);
184 }
185
186 void mptcp_pm_subflow_check_next(struct mptcp_sock *msk,
187 const struct mptcp_subflow_context *subflow)
188 {
189 struct mptcp_pm_data *pm = &msk->pm;
190 bool update_subflows;
191
192 update_subflows = subflow->request_join || subflow->mp_join;
193 if (mptcp_pm_is_userspace(msk)) {
194 if (update_subflows) {
195 spin_lock_bh(&pm->lock);
196 pm->subflows--;
197 spin_unlock_bh(&pm->lock);
198 }
199 return;
200 }
201
202 if (!READ_ONCE(pm->work_pending) && !update_subflows)
203 return;
204
205 spin_lock_bh(&pm->lock);
206 if (update_subflows)
207 __mptcp_pm_close_subflow(msk);
208
209 /* Even if this subflow is not really established, tell the PM to try
210 * to pick the next ones, if possible.
211 */
212 if (mptcp_pm_nl_check_work_pending(msk))
213 mptcp_pm_schedule_work(msk, MPTCP_PM_SUBFLOW_ESTABLISHED);
214
215 spin_unlock_bh(&pm->lock);
216 }
217
218 void mptcp_pm_add_addr_received(const struct sock *ssk,
219 const struct mptcp_addr_info *addr)
220 {
221 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
222 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
223 struct mptcp_pm_data *pm = &msk->pm;
224
225 pr_debug("msk=%p remote_id=%d accept=%d", msk, addr->id,
226 READ_ONCE(pm->accept_addr));
227
228 mptcp_event_addr_announced(ssk, addr);
229
230 spin_lock_bh(&pm->lock);
231
232 if (mptcp_pm_is_userspace(msk)) {
233 if (mptcp_userspace_pm_active(msk)) {
234 mptcp_pm_announce_addr(msk, addr, true);
235 mptcp_pm_add_addr_send_ack(msk);
236 } else {
237 __MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_ADDADDRDROP);
238 }
239 } else if (!READ_ONCE(pm->accept_addr)) {
240 mptcp_pm_announce_addr(msk, addr, true);
241 mptcp_pm_add_addr_send_ack(msk);
242 } else if (mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_RECEIVED)) {
243 pm->remote = *addr;
244 } else {
245 __MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_ADDADDRDROP);
246 }
247
248 spin_unlock_bh(&pm->lock);
249 }
250
251 void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk,
252 const struct mptcp_addr_info *addr)
253 {
254 struct mptcp_pm_data *pm = &msk->pm;
255
256 pr_debug("msk=%p", msk);
257
258 spin_lock_bh(&pm->lock);
259
260 if (mptcp_lookup_anno_list_by_saddr(msk, addr) && READ_ONCE(pm->work_pending))
261 mptcp_pm_schedule_work(msk, MPTCP_PM_SUBFLOW_ESTABLISHED);
262
263 spin_unlock_bh(&pm->lock);
264 }
265
266 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk)
267 {
268 if (!mptcp_pm_should_add_signal(msk))
269 return;
270
271 mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_SEND_ACK);
272 }
273
274 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk,
275 const struct mptcp_rm_list *rm_list)
276 {
277 struct mptcp_pm_data *pm = &msk->pm;
278 u8 i;
279
280 pr_debug("msk=%p remote_ids_nr=%d", msk, rm_list->nr);
281
282 for (i = 0; i < rm_list->nr; i++)
283 mptcp_event_addr_removed(msk, rm_list->ids[i]);
284
285 spin_lock_bh(&pm->lock);
286 if (mptcp_pm_schedule_work(msk, MPTCP_PM_RM_ADDR_RECEIVED))
287 pm->rm_list_rx = *rm_list;
288 else
289 __MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_RMADDRDROP);
290 spin_unlock_bh(&pm->lock);
291 }
292
293 void mptcp_pm_mp_prio_received(struct sock *ssk, u8 bkup)
294 {
295 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
296 struct sock *sk = subflow->conn;
297 struct mptcp_sock *msk;
298
299 pr_debug("subflow->backup=%d, bkup=%d\n", subflow->backup, bkup);
300 msk = mptcp_sk(sk);
301 if (subflow->backup != bkup)
302 subflow->backup = bkup;
303
304 mptcp_event(MPTCP_EVENT_SUB_PRIORITY, msk, ssk, GFP_ATOMIC);
305 }
306
307 void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq)
308 {
309 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
310 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
311
312 pr_debug("fail_seq=%llu", fail_seq);
313
314 if (!READ_ONCE(msk->allow_infinite_fallback))
315 return;
316
317 if (!subflow->fail_tout) {
318 pr_debug("send MP_FAIL response and infinite map");
319
320 subflow->send_mp_fail = 1;
321 subflow->send_infinite_map = 1;
322 tcp_send_ack(sk);
323 } else {
324 pr_debug("MP_FAIL response received");
325 WRITE_ONCE(subflow->fail_tout, 0);
326 }
327 }
328
329 /* path manager helpers */
330
331 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, const struct sk_buff *skb,
332 unsigned int opt_size, unsigned int remaining,
333 struct mptcp_addr_info *addr, bool *echo,
334 bool *drop_other_suboptions)
335 {
336 int ret = false;
337 u8 add_addr;
338 u8 family;
339 bool port;
340
341 spin_lock_bh(&msk->pm.lock);
342
343 /* double check after the lock is acquired */
344 if (!mptcp_pm_should_add_signal(msk))
345 goto out_unlock;
346
347 /* always drop every other options for pure ack ADD_ADDR; this is a
348 * plain dup-ack from TCP perspective. The other MPTCP-relevant info,
349 * if any, will be carried by the 'original' TCP ack
350 */
351 if (skb && skb_is_tcp_pure_ack(skb)) {
352 remaining += opt_size;
353 *drop_other_suboptions = true;
354 }
355
356 *echo = mptcp_pm_should_add_signal_echo(msk);
357 port = !!(*echo ? msk->pm.remote.port : msk->pm.local.port);
358
359 family = *echo ? msk->pm.remote.family : msk->pm.local.family;
360 if (remaining < mptcp_add_addr_len(family, *echo, port))
361 goto out_unlock;
362
363 if (*echo) {
364 *addr = msk->pm.remote;
365 add_addr = msk->pm.addr_signal & ~BIT(MPTCP_ADD_ADDR_ECHO);
366 } else {
367 *addr = msk->pm.local;
368 add_addr = msk->pm.addr_signal & ~BIT(MPTCP_ADD_ADDR_SIGNAL);
369 }
370 WRITE_ONCE(msk->pm.addr_signal, add_addr);
371 ret = true;
372
373 out_unlock:
374 spin_unlock_bh(&msk->pm.lock);
375 return ret;
376 }
377
378 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
379 struct mptcp_rm_list *rm_list)
380 {
381 int ret = false, len;
382 u8 rm_addr;
383
384 spin_lock_bh(&msk->pm.lock);
385
386 /* double check after the lock is acquired */
387 if (!mptcp_pm_should_rm_signal(msk))
388 goto out_unlock;
389
390 rm_addr = msk->pm.addr_signal & ~BIT(MPTCP_RM_ADDR_SIGNAL);
391 len = mptcp_rm_addr_len(&msk->pm.rm_list_tx);
392 if (len < 0) {
393 WRITE_ONCE(msk->pm.addr_signal, rm_addr);
394 goto out_unlock;
395 }
396 if (remaining < len)
397 goto out_unlock;
398
399 *rm_list = msk->pm.rm_list_tx;
400 WRITE_ONCE(msk->pm.addr_signal, rm_addr);
401 ret = true;
402
403 out_unlock:
404 spin_unlock_bh(&msk->pm.lock);
405 return ret;
406 }
407
408 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
409 {
410 struct mptcp_addr_info skc_local;
411 struct mptcp_addr_info msk_local;
412
413 if (WARN_ON_ONCE(!msk))
414 return -1;
415
416 /* The 0 ID mapping is defined by the first subflow, copied into the msk
417 * addr
418 */
419 mptcp_local_address((struct sock_common *)msk, &msk_local);
420 mptcp_local_address((struct sock_common *)skc, &skc_local);
421 if (mptcp_addresses_equal(&msk_local, &skc_local, false))
422 return 0;
423
424 if (mptcp_pm_is_userspace(msk))
425 return mptcp_userspace_pm_get_local_id(msk, &skc_local);
426 return mptcp_pm_nl_get_local_id(msk, &skc_local);
427 }
428
429 bool mptcp_pm_is_backup(struct mptcp_sock *msk, struct sock_common *skc)
430 {
431 struct mptcp_addr_info skc_local;
432
433 mptcp_local_address((struct sock_common *)skc, &skc_local);
434
435 if (mptcp_pm_is_userspace(msk))
436 return mptcp_userspace_pm_is_backup(msk, &skc_local);
437
438 return mptcp_pm_nl_is_backup(msk, &skc_local);
439 }
440
441 int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id,
442 u8 *flags, int *ifindex)
443 {
444 *flags = 0;
445 *ifindex = 0;
446
447 if (!id)
448 return 0;
449
450 if (mptcp_pm_is_userspace(msk))
451 return mptcp_userspace_pm_get_flags_and_ifindex_by_id(msk, id, flags, ifindex);
452 return mptcp_pm_nl_get_flags_and_ifindex_by_id(msk, id, flags, ifindex);
453 }
454
455 int mptcp_pm_get_addr(struct sk_buff *skb, struct genl_info *info)
456 {
457 if (info->attrs[MPTCP_PM_ATTR_TOKEN])
458 return mptcp_userspace_pm_get_addr(skb, info);
459 return mptcp_pm_nl_get_addr(skb, info);
460 }
461
462 int mptcp_pm_dump_addr(struct sk_buff *msg, struct netlink_callback *cb)
463 {
464 const struct genl_info *info = genl_info_dump(cb);
465
466 if (info->attrs[MPTCP_PM_ATTR_TOKEN])
467 return mptcp_userspace_pm_dump_addr(msg, cb);
468 return mptcp_pm_nl_dump_addr(msg, cb);
469 }
470
471 int mptcp_pm_set_flags(struct sk_buff *skb, struct genl_info *info)
472 {
473 if (info->attrs[MPTCP_PM_ATTR_TOKEN])
474 return mptcp_userspace_pm_set_flags(skb, info);
475 return mptcp_pm_nl_set_flags(skb, info);
476 }
477
478 void mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk)
479 {
480 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
481 u32 rcv_tstamp = READ_ONCE(tcp_sk(ssk)->rcv_tstamp);
482
483 /* keep track of rtx periods with no progress */
484 if (!subflow->stale_count) {
485 subflow->stale_rcv_tstamp = rcv_tstamp;
486 subflow->stale_count++;
487 } else if (subflow->stale_rcv_tstamp == rcv_tstamp) {
488 if (subflow->stale_count < U8_MAX)
489 subflow->stale_count++;
490 mptcp_pm_nl_subflow_chk_stale(msk, ssk);
491 } else {
492 subflow->stale_count = 0;
493 mptcp_subflow_set_active(subflow);
494 }
495 }
496
497 /* if sk is ipv4 or ipv6_only allows only same-family local and remote addresses,
498 * otherwise allow any matching local/remote pair
499 */
500 bool mptcp_pm_addr_families_match(const struct sock *sk,
501 const struct mptcp_addr_info *loc,
502 const struct mptcp_addr_info *rem)
503 {
504 bool mptcp_is_v4 = sk->sk_family == AF_INET;
505
506 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
507 bool loc_is_v4 = loc->family == AF_INET || ipv6_addr_v4mapped(&loc->addr6);
508 bool rem_is_v4 = rem->family == AF_INET || ipv6_addr_v4mapped(&rem->addr6);
509
510 if (mptcp_is_v4)
511 return loc_is_v4 && rem_is_v4;
512
513 if (ipv6_only_sock(sk))
514 return !loc_is_v4 && !rem_is_v4;
515
516 return loc_is_v4 == rem_is_v4;
517 #else
518 return mptcp_is_v4 && loc->family == AF_INET && rem->family == AF_INET;
519 #endif
520 }
521
522 void mptcp_pm_data_reset(struct mptcp_sock *msk)
523 {
524 u8 pm_type = mptcp_get_pm_type(sock_net((struct sock *)msk));
525 struct mptcp_pm_data *pm = &msk->pm;
526
527 pm->add_addr_signaled = 0;
528 pm->add_addr_accepted = 0;
529 pm->local_addr_used = 0;
530 pm->subflows = 0;
531 pm->rm_list_tx.nr = 0;
532 pm->rm_list_rx.nr = 0;
533 WRITE_ONCE(pm->pm_type, pm_type);
534
535 if (pm_type == MPTCP_PM_TYPE_KERNEL) {
536 bool subflows_allowed = !!mptcp_pm_get_subflows_max(msk);
537
538 /* pm->work_pending must be only be set to 'true' when
539 * pm->pm_type is set to MPTCP_PM_TYPE_KERNEL
540 */
541 WRITE_ONCE(pm->work_pending,
542 (!!mptcp_pm_get_local_addr_max(msk) &&
543 subflows_allowed) ||
544 !!mptcp_pm_get_add_addr_signal_max(msk));
545 WRITE_ONCE(pm->accept_addr,
546 !!mptcp_pm_get_add_addr_accept_max(msk) &&
547 subflows_allowed);
548 WRITE_ONCE(pm->accept_subflow, subflows_allowed);
549 } else {
550 WRITE_ONCE(pm->work_pending, 0);
551 WRITE_ONCE(pm->accept_addr, 0);
552 WRITE_ONCE(pm->accept_subflow, 0);
553 }
554
555 WRITE_ONCE(pm->addr_signal, 0);
556 WRITE_ONCE(pm->remote_deny_join_id0, false);
557 pm->status = 0;
558 bitmap_fill(msk->pm.id_avail_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
559 }
560
561 void mptcp_pm_data_init(struct mptcp_sock *msk)
562 {
563 spin_lock_init(&msk->pm.lock);
564 INIT_LIST_HEAD(&msk->pm.anno_list);
565 INIT_LIST_HEAD(&msk->pm.userspace_pm_local_addr_list);
566 mptcp_pm_data_reset(msk);
567 }
568
569 void __init mptcp_pm_init(void)
570 {
571 mptcp_pm_nl_init();
572 }
573
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