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1// SPDX-License-Identifier: GPL-2.0
2/* Multipath TCP
3 *
4 * Copyright (c) 2017 - 2019, Intel Corporation.
5 */
6
7#define pr_fmt(fmt) "MPTCP: " fmt
8
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/netdevice.h>
12#include <linux/sched/signal.h>
13#include <linux/atomic.h>
14#include <net/sock.h>
15#include <net/inet_common.h>
16#include <net/inet_hashtables.h>
17#include <net/protocol.h>
18#include <net/tcp.h>
19#include <net/tcp_states.h>
20#if IS_ENABLED(CONFIG_MPTCP_IPV6)
21#include <net/transp_v6.h>
22#endif
23#include <net/mptcp.h>
24#include <net/xfrm.h>
25#include <asm/ioctls.h>
26#include "protocol.h"
27#include "mib.h"
28
29#define CREATE_TRACE_POINTS
30#include <trace/events/mptcp.h>
31
32#if IS_ENABLED(CONFIG_MPTCP_IPV6)
33struct mptcp6_sock {
34 struct mptcp_sock msk;
35 struct ipv6_pinfo np;
36};
37#endif
38
39enum {
40 MPTCP_CMSG_TS = BIT(0),
41 MPTCP_CMSG_INQ = BIT(1),
42};
43
44static struct percpu_counter mptcp_sockets_allocated ____cacheline_aligned_in_smp;
45
46static void __mptcp_destroy_sock(struct sock *sk);
47static void __mptcp_check_send_data_fin(struct sock *sk);
48
49DEFINE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
50static struct net_device mptcp_napi_dev;
51
52/* If msk has an initial subflow socket, and the MP_CAPABLE handshake has not
53 * completed yet or has failed, return the subflow socket.
54 * Otherwise return NULL.
55 */
56struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk)
57{
58 if (!msk->subflow || READ_ONCE(msk->can_ack))
59 return NULL;
60
61 return msk->subflow;
62}
63
64/* Returns end sequence number of the receiver's advertised window */
65static u64 mptcp_wnd_end(const struct mptcp_sock *msk)
66{
67 return READ_ONCE(msk->wnd_end);
68}
69
70static bool mptcp_is_tcpsk(struct sock *sk)
71{
72 struct socket *sock = sk->sk_socket;
73
74 if (unlikely(sk->sk_prot == &tcp_prot)) {
75 /* we are being invoked after mptcp_accept() has
76 * accepted a non-mp-capable flow: sk is a tcp_sk,
77 * not an mptcp one.
78 *
79 * Hand the socket over to tcp so all further socket ops
80 * bypass mptcp.
81 */
82 sock->ops = &inet_stream_ops;
83 return true;
84#if IS_ENABLED(CONFIG_MPTCP_IPV6)
85 } else if (unlikely(sk->sk_prot == &tcpv6_prot)) {
86 sock->ops = &inet6_stream_ops;
87 return true;
88#endif
89 }
90
91 return false;
92}
93
94static int __mptcp_socket_create(struct mptcp_sock *msk)
95{
96 struct mptcp_subflow_context *subflow;
97 struct sock *sk = (struct sock *)msk;
98 struct socket *ssock;
99 int err;
100
101 err = mptcp_subflow_create_socket(sk, sk->sk_family, &ssock);
102 if (err)
103 return err;
104
105 msk->first = ssock->sk;
106 msk->subflow = ssock;
107 subflow = mptcp_subflow_ctx(ssock->sk);
108 list_add(&subflow->node, &msk->conn_list);
109 sock_hold(ssock->sk);
110 subflow->request_mptcp = 1;
111
112 /* This is the first subflow, always with id 0 */
113 subflow->local_id_valid = 1;
114 mptcp_sock_graft(msk->first, sk->sk_socket);
115
116 return 0;
117}
118
119static void mptcp_drop(struct sock *sk, struct sk_buff *skb)
120{
121 sk_drops_add(sk, skb);
122 __kfree_skb(skb);
123}
124
125static void mptcp_rmem_charge(struct sock *sk, int size)
126{
127 mptcp_sk(sk)->rmem_fwd_alloc -= size;
128}
129
130static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to,
131 struct sk_buff *from)
132{
133 bool fragstolen;
134 int delta;
135
136 if (MPTCP_SKB_CB(from)->offset ||
137 !skb_try_coalesce(to, from, &fragstolen, &delta))
138 return false;
139
140 pr_debug("colesced seq %llx into %llx new len %d new end seq %llx",
141 MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq,
142 to->len, MPTCP_SKB_CB(from)->end_seq);
143 MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq;
144
145 /* note the fwd memory can reach a negative value after accounting
146 * for the delta, but the later skb free will restore a non
147 * negative one
148 */
149 atomic_add(delta, &sk->sk_rmem_alloc);
150 mptcp_rmem_charge(sk, delta);
151 kfree_skb_partial(from, fragstolen);
152
153 return true;
154}
155
156static bool mptcp_ooo_try_coalesce(struct mptcp_sock *msk, struct sk_buff *to,
157 struct sk_buff *from)
158{
159 if (MPTCP_SKB_CB(from)->map_seq != MPTCP_SKB_CB(to)->end_seq)
160 return false;
161
162 return mptcp_try_coalesce((struct sock *)msk, to, from);
163}
164
165static void __mptcp_rmem_reclaim(struct sock *sk, int amount)
166{
167 amount >>= PAGE_SHIFT;
168 mptcp_sk(sk)->rmem_fwd_alloc -= amount << PAGE_SHIFT;
169 __sk_mem_reduce_allocated(sk, amount);
170}
171
172static void mptcp_rmem_uncharge(struct sock *sk, int size)
173{
174 struct mptcp_sock *msk = mptcp_sk(sk);
175 int reclaimable;
176
177 msk->rmem_fwd_alloc += size;
178 reclaimable = msk->rmem_fwd_alloc - sk_unused_reserved_mem(sk);
179
180 /* see sk_mem_uncharge() for the rationale behind the following schema */
181 if (unlikely(reclaimable >= PAGE_SIZE))
182 __mptcp_rmem_reclaim(sk, reclaimable);
183}
184
185static void mptcp_rfree(struct sk_buff *skb)
186{
187 unsigned int len = skb->truesize;
188 struct sock *sk = skb->sk;
189
190 atomic_sub(len, &sk->sk_rmem_alloc);
191 mptcp_rmem_uncharge(sk, len);
192}
193
194void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk)
195{
196 skb_orphan(skb);
197 skb->sk = sk;
198 skb->destructor = mptcp_rfree;
199 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
200 mptcp_rmem_charge(sk, skb->truesize);
201}
202
203/* "inspired" by tcp_data_queue_ofo(), main differences:
204 * - use mptcp seqs
205 * - don't cope with sacks
206 */
207static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb)
208{
209 struct sock *sk = (struct sock *)msk;
210 struct rb_node **p, *parent;
211 u64 seq, end_seq, max_seq;
212 struct sk_buff *skb1;
213
214 seq = MPTCP_SKB_CB(skb)->map_seq;
215 end_seq = MPTCP_SKB_CB(skb)->end_seq;
216 max_seq = atomic64_read(&msk->rcv_wnd_sent);
217
218 pr_debug("msk=%p seq=%llx limit=%llx empty=%d", msk, seq, max_seq,
219 RB_EMPTY_ROOT(&msk->out_of_order_queue));
220 if (after64(end_seq, max_seq)) {
221 /* out of window */
222 mptcp_drop(sk, skb);
223 pr_debug("oow by %lld, rcv_wnd_sent %llu\n",
224 (unsigned long long)end_seq - (unsigned long)max_seq,
225 (unsigned long long)atomic64_read(&msk->rcv_wnd_sent));
226 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_NODSSWINDOW);
227 return;
228 }
229
230 p = &msk->out_of_order_queue.rb_node;
231 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUE);
232 if (RB_EMPTY_ROOT(&msk->out_of_order_queue)) {
233 rb_link_node(&skb->rbnode, NULL, p);
234 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
235 msk->ooo_last_skb = skb;
236 goto end;
237 }
238
239 /* with 2 subflows, adding at end of ooo queue is quite likely
240 * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup.
241 */
242 if (mptcp_ooo_try_coalesce(msk, msk->ooo_last_skb, skb)) {
243 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
244 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
245 return;
246 }
247
248 /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */
249 if (!before64(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) {
250 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
251 parent = &msk->ooo_last_skb->rbnode;
252 p = &parent->rb_right;
253 goto insert;
254 }
255
256 /* Find place to insert this segment. Handle overlaps on the way. */
257 parent = NULL;
258 while (*p) {
259 parent = *p;
260 skb1 = rb_to_skb(parent);
261 if (before64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
262 p = &parent->rb_left;
263 continue;
264 }
265 if (before64(seq, MPTCP_SKB_CB(skb1)->end_seq)) {
266 if (!after64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) {
267 /* All the bits are present. Drop. */
268 mptcp_drop(sk, skb);
269 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
270 return;
271 }
272 if (after64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
273 /* partial overlap:
274 * | skb |
275 * | skb1 |
276 * continue traversing
277 */
278 } else {
279 /* skb's seq == skb1's seq and skb covers skb1.
280 * Replace skb1 with skb.
281 */
282 rb_replace_node(&skb1->rbnode, &skb->rbnode,
283 &msk->out_of_order_queue);
284 mptcp_drop(sk, skb1);
285 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
286 goto merge_right;
287 }
288 } else if (mptcp_ooo_try_coalesce(msk, skb1, skb)) {
289 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
290 return;
291 }
292 p = &parent->rb_right;
293 }
294
295insert:
296 /* Insert segment into RB tree. */
297 rb_link_node(&skb->rbnode, parent, p);
298 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
299
300merge_right:
301 /* Remove other segments covered by skb. */
302 while ((skb1 = skb_rb_next(skb)) != NULL) {
303 if (before64(end_seq, MPTCP_SKB_CB(skb1)->end_seq))
304 break;
305 rb_erase(&skb1->rbnode, &msk->out_of_order_queue);
306 mptcp_drop(sk, skb1);
307 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
308 }
309 /* If there is no skb after us, we are the last_skb ! */
310 if (!skb1)
311 msk->ooo_last_skb = skb;
312
313end:
314 skb_condense(skb);
315 mptcp_set_owner_r(skb, sk);
316}
317
318static bool mptcp_rmem_schedule(struct sock *sk, struct sock *ssk, int size)
319{
320 struct mptcp_sock *msk = mptcp_sk(sk);
321 int amt, amount;
322
323 if (size <= msk->rmem_fwd_alloc)
324 return true;
325
326 size -= msk->rmem_fwd_alloc;
327 amt = sk_mem_pages(size);
328 amount = amt << PAGE_SHIFT;
329 if (!__sk_mem_raise_allocated(sk, size, amt, SK_MEM_RECV))
330 return false;
331
332 msk->rmem_fwd_alloc += amount;
333 return true;
334}
335
336static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk,
337 struct sk_buff *skb, unsigned int offset,
338 size_t copy_len)
339{
340 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
341 struct sock *sk = (struct sock *)msk;
342 struct sk_buff *tail;
343 bool has_rxtstamp;
344
345 __skb_unlink(skb, &ssk->sk_receive_queue);
346
347 skb_ext_reset(skb);
348 skb_orphan(skb);
349
350 /* try to fetch required memory from subflow */
351 if (!mptcp_rmem_schedule(sk, ssk, skb->truesize))
352 goto drop;
353
354 has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp;
355
356 /* the skb map_seq accounts for the skb offset:
357 * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq
358 * value
359 */
360 MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow);
361 MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len;
362 MPTCP_SKB_CB(skb)->offset = offset;
363 MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp;
364
365 if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) {
366 /* in sequence */
367 WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len);
368 tail = skb_peek_tail(&sk->sk_receive_queue);
369 if (tail && mptcp_try_coalesce(sk, tail, skb))
370 return true;
371
372 mptcp_set_owner_r(skb, sk);
373 __skb_queue_tail(&sk->sk_receive_queue, skb);
374 return true;
375 } else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) {
376 mptcp_data_queue_ofo(msk, skb);
377 return false;
378 }
379
380 /* old data, keep it simple and drop the whole pkt, sender
381 * will retransmit as needed, if needed.
382 */
383 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
384drop:
385 mptcp_drop(sk, skb);
386 return false;
387}
388
389static void mptcp_stop_timer(struct sock *sk)
390{
391 struct inet_connection_sock *icsk = inet_csk(sk);
392
393 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
394 mptcp_sk(sk)->timer_ival = 0;
395}
396
397static void mptcp_close_wake_up(struct sock *sk)
398{
399 if (sock_flag(sk, SOCK_DEAD))
400 return;
401
402 sk->sk_state_change(sk);
403 if (sk->sk_shutdown == SHUTDOWN_MASK ||
404 sk->sk_state == TCP_CLOSE)
405 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
406 else
407 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
408}
409
410static bool mptcp_pending_data_fin_ack(struct sock *sk)
411{
412 struct mptcp_sock *msk = mptcp_sk(sk);
413
414 return !__mptcp_check_fallback(msk) &&
415 ((1 << sk->sk_state) &
416 (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) &&
417 msk->write_seq == READ_ONCE(msk->snd_una);
418}
419
420static void mptcp_check_data_fin_ack(struct sock *sk)
421{
422 struct mptcp_sock *msk = mptcp_sk(sk);
423
424 /* Look for an acknowledged DATA_FIN */
425 if (mptcp_pending_data_fin_ack(sk)) {
426 WRITE_ONCE(msk->snd_data_fin_enable, 0);
427
428 switch (sk->sk_state) {
429 case TCP_FIN_WAIT1:
430 inet_sk_state_store(sk, TCP_FIN_WAIT2);
431 break;
432 case TCP_CLOSING:
433 case TCP_LAST_ACK:
434 inet_sk_state_store(sk, TCP_CLOSE);
435 break;
436 }
437
438 mptcp_close_wake_up(sk);
439 }
440}
441
442static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq)
443{
444 struct mptcp_sock *msk = mptcp_sk(sk);
445
446 if (READ_ONCE(msk->rcv_data_fin) &&
447 ((1 << sk->sk_state) &
448 (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) {
449 u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq);
450
451 if (msk->ack_seq == rcv_data_fin_seq) {
452 if (seq)
453 *seq = rcv_data_fin_seq;
454
455 return true;
456 }
457 }
458
459 return false;
460}
461
462static void mptcp_set_datafin_timeout(const struct sock *sk)
463{
464 struct inet_connection_sock *icsk = inet_csk(sk);
465 u32 retransmits;
466
467 retransmits = min_t(u32, icsk->icsk_retransmits,
468 ilog2(TCP_RTO_MAX / TCP_RTO_MIN));
469
470 mptcp_sk(sk)->timer_ival = TCP_RTO_MIN << retransmits;
471}
472
473static void __mptcp_set_timeout(struct sock *sk, long tout)
474{
475 mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
476}
477
478static long mptcp_timeout_from_subflow(const struct mptcp_subflow_context *subflow)
479{
480 const struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
481
482 return inet_csk(ssk)->icsk_pending && !subflow->stale_count ?
483 inet_csk(ssk)->icsk_timeout - jiffies : 0;
484}
485
486static void mptcp_set_timeout(struct sock *sk)
487{
488 struct mptcp_subflow_context *subflow;
489 long tout = 0;
490
491 mptcp_for_each_subflow(mptcp_sk(sk), subflow)
492 tout = max(tout, mptcp_timeout_from_subflow(subflow));
493 __mptcp_set_timeout(sk, tout);
494}
495
496static inline bool tcp_can_send_ack(const struct sock *ssk)
497{
498 return !((1 << inet_sk_state_load(ssk)) &
499 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE | TCPF_LISTEN));
500}
501
502void __mptcp_subflow_send_ack(struct sock *ssk)
503{
504 if (tcp_can_send_ack(ssk))
505 tcp_send_ack(ssk);
506}
507
508static void mptcp_subflow_send_ack(struct sock *ssk)
509{
510 bool slow;
511
512 slow = lock_sock_fast(ssk);
513 __mptcp_subflow_send_ack(ssk);
514 unlock_sock_fast(ssk, slow);
515}
516
517static void mptcp_send_ack(struct mptcp_sock *msk)
518{
519 struct mptcp_subflow_context *subflow;
520
521 mptcp_for_each_subflow(msk, subflow)
522 mptcp_subflow_send_ack(mptcp_subflow_tcp_sock(subflow));
523}
524
525static void mptcp_subflow_cleanup_rbuf(struct sock *ssk)
526{
527 bool slow;
528
529 slow = lock_sock_fast(ssk);
530 if (tcp_can_send_ack(ssk))
531 tcp_cleanup_rbuf(ssk, 1);
532 unlock_sock_fast(ssk, slow);
533}
534
535static bool mptcp_subflow_could_cleanup(const struct sock *ssk, bool rx_empty)
536{
537 const struct inet_connection_sock *icsk = inet_csk(ssk);
538 u8 ack_pending = READ_ONCE(icsk->icsk_ack.pending);
539 const struct tcp_sock *tp = tcp_sk(ssk);
540
541 return (ack_pending & ICSK_ACK_SCHED) &&
542 ((READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->rcv_wup) >
543 READ_ONCE(icsk->icsk_ack.rcv_mss)) ||
544 (rx_empty && ack_pending &
545 (ICSK_ACK_PUSHED2 | ICSK_ACK_PUSHED)));
546}
547
548static void mptcp_cleanup_rbuf(struct mptcp_sock *msk)
549{
550 int old_space = READ_ONCE(msk->old_wspace);
551 struct mptcp_subflow_context *subflow;
552 struct sock *sk = (struct sock *)msk;
553 int space = __mptcp_space(sk);
554 bool cleanup, rx_empty;
555
556 cleanup = (space > 0) && (space >= (old_space << 1));
557 rx_empty = !__mptcp_rmem(sk);
558
559 mptcp_for_each_subflow(msk, subflow) {
560 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
561
562 if (cleanup || mptcp_subflow_could_cleanup(ssk, rx_empty))
563 mptcp_subflow_cleanup_rbuf(ssk);
564 }
565}
566
567static bool mptcp_check_data_fin(struct sock *sk)
568{
569 struct mptcp_sock *msk = mptcp_sk(sk);
570 u64 rcv_data_fin_seq;
571 bool ret = false;
572
573 if (__mptcp_check_fallback(msk))
574 return ret;
575
576 /* Need to ack a DATA_FIN received from a peer while this side
577 * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2.
578 * msk->rcv_data_fin was set when parsing the incoming options
579 * at the subflow level and the msk lock was not held, so this
580 * is the first opportunity to act on the DATA_FIN and change
581 * the msk state.
582 *
583 * If we are caught up to the sequence number of the incoming
584 * DATA_FIN, send the DATA_ACK now and do state transition. If
585 * not caught up, do nothing and let the recv code send DATA_ACK
586 * when catching up.
587 */
588
589 if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) {
590 WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1);
591 WRITE_ONCE(msk->rcv_data_fin, 0);
592
593 sk->sk_shutdown |= RCV_SHUTDOWN;
594 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
595
596 switch (sk->sk_state) {
597 case TCP_ESTABLISHED:
598 inet_sk_state_store(sk, TCP_CLOSE_WAIT);
599 break;
600 case TCP_FIN_WAIT1:
601 inet_sk_state_store(sk, TCP_CLOSING);
602 break;
603 case TCP_FIN_WAIT2:
604 inet_sk_state_store(sk, TCP_CLOSE);
605 break;
606 default:
607 /* Other states not expected */
608 WARN_ON_ONCE(1);
609 break;
610 }
611
612 ret = true;
613 mptcp_send_ack(msk);
614 mptcp_close_wake_up(sk);
615 }
616 return ret;
617}
618
619static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
620 struct sock *ssk,
621 unsigned int *bytes)
622{
623 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
624 struct sock *sk = (struct sock *)msk;
625 unsigned int moved = 0;
626 bool more_data_avail;
627 struct tcp_sock *tp;
628 bool done = false;
629 int sk_rbuf;
630
631 sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
632
633 if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
634 int ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
635
636 if (unlikely(ssk_rbuf > sk_rbuf)) {
637 WRITE_ONCE(sk->sk_rcvbuf, ssk_rbuf);
638 sk_rbuf = ssk_rbuf;
639 }
640 }
641
642 pr_debug("msk=%p ssk=%p", msk, ssk);
643 tp = tcp_sk(ssk);
644 do {
645 u32 map_remaining, offset;
646 u32 seq = tp->copied_seq;
647 struct sk_buff *skb;
648 bool fin;
649
650 /* try to move as much data as available */
651 map_remaining = subflow->map_data_len -
652 mptcp_subflow_get_map_offset(subflow);
653
654 skb = skb_peek(&ssk->sk_receive_queue);
655 if (!skb) {
656 /* With racing move_skbs_to_msk() and __mptcp_move_skbs(),
657 * a different CPU can have already processed the pending
658 * data, stop here or we can enter an infinite loop
659 */
660 if (!moved)
661 done = true;
662 break;
663 }
664
665 if (__mptcp_check_fallback(msk)) {
666 /* Under fallback skbs have no MPTCP extension and TCP could
667 * collapse them between the dummy map creation and the
668 * current dequeue. Be sure to adjust the map size.
669 */
670 map_remaining = skb->len;
671 subflow->map_data_len = skb->len;
672 }
673
674 offset = seq - TCP_SKB_CB(skb)->seq;
675 fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
676 if (fin) {
677 done = true;
678 seq++;
679 }
680
681 if (offset < skb->len) {
682 size_t len = skb->len - offset;
683
684 if (tp->urg_data)
685 done = true;
686
687 if (__mptcp_move_skb(msk, ssk, skb, offset, len))
688 moved += len;
689 seq += len;
690
691 if (WARN_ON_ONCE(map_remaining < len))
692 break;
693 } else {
694 WARN_ON_ONCE(!fin);
695 sk_eat_skb(ssk, skb);
696 done = true;
697 }
698
699 WRITE_ONCE(tp->copied_seq, seq);
700 more_data_avail = mptcp_subflow_data_available(ssk);
701
702 if (atomic_read(&sk->sk_rmem_alloc) > sk_rbuf) {
703 done = true;
704 break;
705 }
706 } while (more_data_avail);
707
708 *bytes += moved;
709 return done;
710}
711
712static bool __mptcp_ofo_queue(struct mptcp_sock *msk)
713{
714 struct sock *sk = (struct sock *)msk;
715 struct sk_buff *skb, *tail;
716 bool moved = false;
717 struct rb_node *p;
718 u64 end_seq;
719
720 p = rb_first(&msk->out_of_order_queue);
721 pr_debug("msk=%p empty=%d", msk, RB_EMPTY_ROOT(&msk->out_of_order_queue));
722 while (p) {
723 skb = rb_to_skb(p);
724 if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq))
725 break;
726
727 p = rb_next(p);
728 rb_erase(&skb->rbnode, &msk->out_of_order_queue);
729
730 if (unlikely(!after64(MPTCP_SKB_CB(skb)->end_seq,
731 msk->ack_seq))) {
732 mptcp_drop(sk, skb);
733 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
734 continue;
735 }
736
737 end_seq = MPTCP_SKB_CB(skb)->end_seq;
738 tail = skb_peek_tail(&sk->sk_receive_queue);
739 if (!tail || !mptcp_ooo_try_coalesce(msk, tail, skb)) {
740 int delta = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq;
741
742 /* skip overlapping data, if any */
743 pr_debug("uncoalesced seq=%llx ack seq=%llx delta=%d",
744 MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq,
745 delta);
746 MPTCP_SKB_CB(skb)->offset += delta;
747 MPTCP_SKB_CB(skb)->map_seq += delta;
748 __skb_queue_tail(&sk->sk_receive_queue, skb);
749 }
750 msk->ack_seq = end_seq;
751 moved = true;
752 }
753 return moved;
754}
755
756/* In most cases we will be able to lock the mptcp socket. If its already
757 * owned, we need to defer to the work queue to avoid ABBA deadlock.
758 */
759static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk)
760{
761 struct sock *sk = (struct sock *)msk;
762 unsigned int moved = 0;
763
764 __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
765 __mptcp_ofo_queue(msk);
766 if (unlikely(ssk->sk_err)) {
767 if (!sock_owned_by_user(sk))
768 __mptcp_error_report(sk);
769 else
770 __set_bit(MPTCP_ERROR_REPORT, &msk->cb_flags);
771 }
772
773 /* If the moves have caught up with the DATA_FIN sequence number
774 * it's time to ack the DATA_FIN and change socket state, but
775 * this is not a good place to change state. Let the workqueue
776 * do it.
777 */
778 if (mptcp_pending_data_fin(sk, NULL))
779 mptcp_schedule_work(sk);
780 return moved > 0;
781}
782
783void mptcp_data_ready(struct sock *sk, struct sock *ssk)
784{
785 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
786 struct mptcp_sock *msk = mptcp_sk(sk);
787 int sk_rbuf, ssk_rbuf;
788
789 /* The peer can send data while we are shutting down this
790 * subflow at msk destruction time, but we must avoid enqueuing
791 * more data to the msk receive queue
792 */
793 if (unlikely(subflow->disposable))
794 return;
795
796 ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
797 sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
798 if (unlikely(ssk_rbuf > sk_rbuf))
799 sk_rbuf = ssk_rbuf;
800
801 /* over limit? can't append more skbs to msk, Also, no need to wake-up*/
802 if (__mptcp_rmem(sk) > sk_rbuf) {
803 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED);
804 return;
805 }
806
807 /* Wake-up the reader only for in-sequence data */
808 mptcp_data_lock(sk);
809 if (move_skbs_to_msk(msk, ssk))
810 sk->sk_data_ready(sk);
811
812 mptcp_data_unlock(sk);
813}
814
815static bool __mptcp_finish_join(struct mptcp_sock *msk, struct sock *ssk)
816{
817 struct sock *sk = (struct sock *)msk;
818
819 if (sk->sk_state != TCP_ESTABLISHED)
820 return false;
821
822 /* attach to msk socket only after we are sure we will deal with it
823 * at close time
824 */
825 if (sk->sk_socket && !ssk->sk_socket)
826 mptcp_sock_graft(ssk, sk->sk_socket);
827
828 mptcp_propagate_sndbuf((struct sock *)msk, ssk);
829 mptcp_sockopt_sync_locked(msk, ssk);
830 return true;
831}
832
833static void __mptcp_flush_join_list(struct sock *sk)
834{
835 struct mptcp_subflow_context *tmp, *subflow;
836 struct mptcp_sock *msk = mptcp_sk(sk);
837
838 list_for_each_entry_safe(subflow, tmp, &msk->join_list, node) {
839 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
840 bool slow = lock_sock_fast(ssk);
841
842 list_move_tail(&subflow->node, &msk->conn_list);
843 if (!__mptcp_finish_join(msk, ssk))
844 mptcp_subflow_reset(ssk);
845 unlock_sock_fast(ssk, slow);
846 }
847}
848
849static bool mptcp_timer_pending(struct sock *sk)
850{
851 return timer_pending(&inet_csk(sk)->icsk_retransmit_timer);
852}
853
854static void mptcp_reset_timer(struct sock *sk)
855{
856 struct inet_connection_sock *icsk = inet_csk(sk);
857 unsigned long tout;
858
859 /* prevent rescheduling on close */
860 if (unlikely(inet_sk_state_load(sk) == TCP_CLOSE))
861 return;
862
863 tout = mptcp_sk(sk)->timer_ival;
864 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout);
865}
866
867bool mptcp_schedule_work(struct sock *sk)
868{
869 if (inet_sk_state_load(sk) != TCP_CLOSE &&
870 schedule_work(&mptcp_sk(sk)->work)) {
871 /* each subflow already holds a reference to the sk, and the
872 * workqueue is invoked by a subflow, so sk can't go away here.
873 */
874 sock_hold(sk);
875 return true;
876 }
877 return false;
878}
879
880void mptcp_subflow_eof(struct sock *sk)
881{
882 if (!test_and_set_bit(MPTCP_WORK_EOF, &mptcp_sk(sk)->flags))
883 mptcp_schedule_work(sk);
884}
885
886static void mptcp_check_for_eof(struct mptcp_sock *msk)
887{
888 struct mptcp_subflow_context *subflow;
889 struct sock *sk = (struct sock *)msk;
890 int receivers = 0;
891
892 mptcp_for_each_subflow(msk, subflow)
893 receivers += !subflow->rx_eof;
894 if (receivers)
895 return;
896
897 if (!(sk->sk_shutdown & RCV_SHUTDOWN)) {
898 /* hopefully temporary hack: propagate shutdown status
899 * to msk, when all subflows agree on it
900 */
901 sk->sk_shutdown |= RCV_SHUTDOWN;
902
903 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
904 sk->sk_data_ready(sk);
905 }
906
907 switch (sk->sk_state) {
908 case TCP_ESTABLISHED:
909 inet_sk_state_store(sk, TCP_CLOSE_WAIT);
910 break;
911 case TCP_FIN_WAIT1:
912 inet_sk_state_store(sk, TCP_CLOSING);
913 break;
914 case TCP_FIN_WAIT2:
915 inet_sk_state_store(sk, TCP_CLOSE);
916 break;
917 default:
918 return;
919 }
920 mptcp_close_wake_up(sk);
921}
922
923static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk)
924{
925 struct mptcp_subflow_context *subflow;
926 struct sock *sk = (struct sock *)msk;
927
928 sock_owned_by_me(sk);
929
930 mptcp_for_each_subflow(msk, subflow) {
931 if (READ_ONCE(subflow->data_avail))
932 return mptcp_subflow_tcp_sock(subflow);
933 }
934
935 return NULL;
936}
937
938static bool mptcp_skb_can_collapse_to(u64 write_seq,
939 const struct sk_buff *skb,
940 const struct mptcp_ext *mpext)
941{
942 if (!tcp_skb_can_collapse_to(skb))
943 return false;
944
945 /* can collapse only if MPTCP level sequence is in order and this
946 * mapping has not been xmitted yet
947 */
948 return mpext && mpext->data_seq + mpext->data_len == write_seq &&
949 !mpext->frozen;
950}
951
952/* we can append data to the given data frag if:
953 * - there is space available in the backing page_frag
954 * - the data frag tail matches the current page_frag free offset
955 * - the data frag end sequence number matches the current write seq
956 */
957static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk,
958 const struct page_frag *pfrag,
959 const struct mptcp_data_frag *df)
960{
961 return df && pfrag->page == df->page &&
962 pfrag->size - pfrag->offset > 0 &&
963 pfrag->offset == (df->offset + df->data_len) &&
964 df->data_seq + df->data_len == msk->write_seq;
965}
966
967static void dfrag_uncharge(struct sock *sk, int len)
968{
969 sk_mem_uncharge(sk, len);
970 sk_wmem_queued_add(sk, -len);
971}
972
973static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag)
974{
975 int len = dfrag->data_len + dfrag->overhead;
976
977 list_del(&dfrag->list);
978 dfrag_uncharge(sk, len);
979 put_page(dfrag->page);
980}
981
982static void __mptcp_clean_una(struct sock *sk)
983{
984 struct mptcp_sock *msk = mptcp_sk(sk);
985 struct mptcp_data_frag *dtmp, *dfrag;
986 u64 snd_una;
987
988 /* on fallback we just need to ignore snd_una, as this is really
989 * plain TCP
990 */
991 if (__mptcp_check_fallback(msk))
992 msk->snd_una = READ_ONCE(msk->snd_nxt);
993
994 snd_una = msk->snd_una;
995 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) {
996 if (after64(dfrag->data_seq + dfrag->data_len, snd_una))
997 break;
998
999 if (unlikely(dfrag == msk->first_pending)) {
1000 /* in recovery mode can see ack after the current snd head */
1001 if (WARN_ON_ONCE(!msk->recovery))
1002 break;
1003
1004 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1005 }
1006
1007 dfrag_clear(sk, dfrag);
1008 }
1009
1010 dfrag = mptcp_rtx_head(sk);
1011 if (dfrag && after64(snd_una, dfrag->data_seq)) {
1012 u64 delta = snd_una - dfrag->data_seq;
1013
1014 /* prevent wrap around in recovery mode */
1015 if (unlikely(delta > dfrag->already_sent)) {
1016 if (WARN_ON_ONCE(!msk->recovery))
1017 goto out;
1018 if (WARN_ON_ONCE(delta > dfrag->data_len))
1019 goto out;
1020 dfrag->already_sent += delta - dfrag->already_sent;
1021 }
1022
1023 dfrag->data_seq += delta;
1024 dfrag->offset += delta;
1025 dfrag->data_len -= delta;
1026 dfrag->already_sent -= delta;
1027
1028 dfrag_uncharge(sk, delta);
1029 }
1030
1031 /* all retransmitted data acked, recovery completed */
1032 if (unlikely(msk->recovery) && after64(msk->snd_una, msk->recovery_snd_nxt))
1033 msk->recovery = false;
1034
1035out:
1036 if (snd_una == READ_ONCE(msk->snd_nxt) &&
1037 snd_una == READ_ONCE(msk->write_seq)) {
1038 if (mptcp_timer_pending(sk) && !mptcp_data_fin_enabled(msk))
1039 mptcp_stop_timer(sk);
1040 } else {
1041 mptcp_reset_timer(sk);
1042 }
1043}
1044
1045static void __mptcp_clean_una_wakeup(struct sock *sk)
1046{
1047 lockdep_assert_held_once(&sk->sk_lock.slock);
1048
1049 __mptcp_clean_una(sk);
1050 mptcp_write_space(sk);
1051}
1052
1053static void mptcp_clean_una_wakeup(struct sock *sk)
1054{
1055 mptcp_data_lock(sk);
1056 __mptcp_clean_una_wakeup(sk);
1057 mptcp_data_unlock(sk);
1058}
1059
1060static void mptcp_enter_memory_pressure(struct sock *sk)
1061{
1062 struct mptcp_subflow_context *subflow;
1063 struct mptcp_sock *msk = mptcp_sk(sk);
1064 bool first = true;
1065
1066 sk_stream_moderate_sndbuf(sk);
1067 mptcp_for_each_subflow(msk, subflow) {
1068 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
1069
1070 if (first)
1071 tcp_enter_memory_pressure(ssk);
1072 sk_stream_moderate_sndbuf(ssk);
1073 first = false;
1074 }
1075}
1076
1077/* ensure we get enough memory for the frag hdr, beyond some minimal amount of
1078 * data
1079 */
1080static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag)
1081{
1082 if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag),
1083 pfrag, sk->sk_allocation)))
1084 return true;
1085
1086 mptcp_enter_memory_pressure(sk);
1087 return false;
1088}
1089
1090static struct mptcp_data_frag *
1091mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag,
1092 int orig_offset)
1093{
1094 int offset = ALIGN(orig_offset, sizeof(long));
1095 struct mptcp_data_frag *dfrag;
1096
1097 dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset);
1098 dfrag->data_len = 0;
1099 dfrag->data_seq = msk->write_seq;
1100 dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag);
1101 dfrag->offset = offset + sizeof(struct mptcp_data_frag);
1102 dfrag->already_sent = 0;
1103 dfrag->page = pfrag->page;
1104
1105 return dfrag;
1106}
1107
1108struct mptcp_sendmsg_info {
1109 int mss_now;
1110 int size_goal;
1111 u16 limit;
1112 u16 sent;
1113 unsigned int flags;
1114 bool data_lock_held;
1115};
1116
1117static int mptcp_check_allowed_size(const struct mptcp_sock *msk, struct sock *ssk,
1118 u64 data_seq, int avail_size)
1119{
1120 u64 window_end = mptcp_wnd_end(msk);
1121 u64 mptcp_snd_wnd;
1122
1123 if (__mptcp_check_fallback(msk))
1124 return avail_size;
1125
1126 mptcp_snd_wnd = window_end - data_seq;
1127 avail_size = min_t(unsigned int, mptcp_snd_wnd, avail_size);
1128
1129 if (unlikely(tcp_sk(ssk)->snd_wnd < mptcp_snd_wnd)) {
1130 tcp_sk(ssk)->snd_wnd = min_t(u64, U32_MAX, mptcp_snd_wnd);
1131 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_SNDWNDSHARED);
1132 }
1133
1134 return avail_size;
1135}
1136
1137static bool __mptcp_add_ext(struct sk_buff *skb, gfp_t gfp)
1138{
1139 struct skb_ext *mpext = __skb_ext_alloc(gfp);
1140
1141 if (!mpext)
1142 return false;
1143 __skb_ext_set(skb, SKB_EXT_MPTCP, mpext);
1144 return true;
1145}
1146
1147static struct sk_buff *__mptcp_do_alloc_tx_skb(struct sock *sk, gfp_t gfp)
1148{
1149 struct sk_buff *skb;
1150
1151 skb = alloc_skb_fclone(MAX_TCP_HEADER, gfp);
1152 if (likely(skb)) {
1153 if (likely(__mptcp_add_ext(skb, gfp))) {
1154 skb_reserve(skb, MAX_TCP_HEADER);
1155 skb->ip_summed = CHECKSUM_PARTIAL;
1156 INIT_LIST_HEAD(&skb->tcp_tsorted_anchor);
1157 return skb;
1158 }
1159 __kfree_skb(skb);
1160 } else {
1161 mptcp_enter_memory_pressure(sk);
1162 }
1163 return NULL;
1164}
1165
1166static struct sk_buff *__mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, gfp_t gfp)
1167{
1168 struct sk_buff *skb;
1169
1170 skb = __mptcp_do_alloc_tx_skb(sk, gfp);
1171 if (!skb)
1172 return NULL;
1173
1174 if (likely(sk_wmem_schedule(ssk, skb->truesize))) {
1175 tcp_skb_entail(ssk, skb);
1176 return skb;
1177 }
1178 tcp_skb_tsorted_anchor_cleanup(skb);
1179 kfree_skb(skb);
1180 return NULL;
1181}
1182
1183static struct sk_buff *mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, bool data_lock_held)
1184{
1185 gfp_t gfp = data_lock_held ? GFP_ATOMIC : sk->sk_allocation;
1186
1187 return __mptcp_alloc_tx_skb(sk, ssk, gfp);
1188}
1189
1190/* note: this always recompute the csum on the whole skb, even
1191 * if we just appended a single frag. More status info needed
1192 */
1193static void mptcp_update_data_checksum(struct sk_buff *skb, int added)
1194{
1195 struct mptcp_ext *mpext = mptcp_get_ext(skb);
1196 __wsum csum = ~csum_unfold(mpext->csum);
1197 int offset = skb->len - added;
1198
1199 mpext->csum = csum_fold(csum_block_add(csum, skb_checksum(skb, offset, added, 0), offset));
1200}
1201
1202static void mptcp_update_infinite_map(struct mptcp_sock *msk,
1203 struct sock *ssk,
1204 struct mptcp_ext *mpext)
1205{
1206 if (!mpext)
1207 return;
1208
1209 mpext->infinite_map = 1;
1210 mpext->data_len = 0;
1211
1212 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPTX);
1213 mptcp_subflow_ctx(ssk)->send_infinite_map = 0;
1214 pr_fallback(msk);
1215 mptcp_do_fallback(ssk);
1216}
1217
1218static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
1219 struct mptcp_data_frag *dfrag,
1220 struct mptcp_sendmsg_info *info)
1221{
1222 u64 data_seq = dfrag->data_seq + info->sent;
1223 int offset = dfrag->offset + info->sent;
1224 struct mptcp_sock *msk = mptcp_sk(sk);
1225 bool zero_window_probe = false;
1226 struct mptcp_ext *mpext = NULL;
1227 bool can_coalesce = false;
1228 bool reuse_skb = true;
1229 struct sk_buff *skb;
1230 size_t copy;
1231 int i;
1232
1233 pr_debug("msk=%p ssk=%p sending dfrag at seq=%llu len=%u already sent=%u",
1234 msk, ssk, dfrag->data_seq, dfrag->data_len, info->sent);
1235
1236 if (WARN_ON_ONCE(info->sent > info->limit ||
1237 info->limit > dfrag->data_len))
1238 return 0;
1239
1240 if (unlikely(!__tcp_can_send(ssk)))
1241 return -EAGAIN;
1242
1243 /* compute send limit */
1244 info->mss_now = tcp_send_mss(ssk, &info->size_goal, info->flags);
1245 copy = info->size_goal;
1246
1247 skb = tcp_write_queue_tail(ssk);
1248 if (skb && copy > skb->len) {
1249 /* Limit the write to the size available in the
1250 * current skb, if any, so that we create at most a new skb.
1251 * Explicitly tells TCP internals to avoid collapsing on later
1252 * queue management operation, to avoid breaking the ext <->
1253 * SSN association set here
1254 */
1255 mpext = skb_ext_find(skb, SKB_EXT_MPTCP);
1256 if (!mptcp_skb_can_collapse_to(data_seq, skb, mpext)) {
1257 TCP_SKB_CB(skb)->eor = 1;
1258 goto alloc_skb;
1259 }
1260
1261 i = skb_shinfo(skb)->nr_frags;
1262 can_coalesce = skb_can_coalesce(skb, i, dfrag->page, offset);
1263 if (!can_coalesce && i >= READ_ONCE(sysctl_max_skb_frags)) {
1264 tcp_mark_push(tcp_sk(ssk), skb);
1265 goto alloc_skb;
1266 }
1267
1268 copy -= skb->len;
1269 } else {
1270alloc_skb:
1271 skb = mptcp_alloc_tx_skb(sk, ssk, info->data_lock_held);
1272 if (!skb)
1273 return -ENOMEM;
1274
1275 i = skb_shinfo(skb)->nr_frags;
1276 reuse_skb = false;
1277 mpext = skb_ext_find(skb, SKB_EXT_MPTCP);
1278 }
1279
1280 /* Zero window and all data acked? Probe. */
1281 copy = mptcp_check_allowed_size(msk, ssk, data_seq, copy);
1282 if (copy == 0) {
1283 u64 snd_una = READ_ONCE(msk->snd_una);
1284
1285 if (snd_una != msk->snd_nxt) {
1286 tcp_remove_empty_skb(ssk);
1287 return 0;
1288 }
1289
1290 zero_window_probe = true;
1291 data_seq = snd_una - 1;
1292 copy = 1;
1293
1294 /* all mptcp-level data is acked, no skbs should be present into the
1295 * ssk write queue
1296 */
1297 WARN_ON_ONCE(reuse_skb);
1298 }
1299
1300 copy = min_t(size_t, copy, info->limit - info->sent);
1301 if (!sk_wmem_schedule(ssk, copy)) {
1302 tcp_remove_empty_skb(ssk);
1303 return -ENOMEM;
1304 }
1305
1306 if (can_coalesce) {
1307 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1308 } else {
1309 get_page(dfrag->page);
1310 skb_fill_page_desc(skb, i, dfrag->page, offset, copy);
1311 }
1312
1313 skb->len += copy;
1314 skb->data_len += copy;
1315 skb->truesize += copy;
1316 sk_wmem_queued_add(ssk, copy);
1317 sk_mem_charge(ssk, copy);
1318 WRITE_ONCE(tcp_sk(ssk)->write_seq, tcp_sk(ssk)->write_seq + copy);
1319 TCP_SKB_CB(skb)->end_seq += copy;
1320 tcp_skb_pcount_set(skb, 0);
1321
1322 /* on skb reuse we just need to update the DSS len */
1323 if (reuse_skb) {
1324 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1325 mpext->data_len += copy;
1326 WARN_ON_ONCE(zero_window_probe);
1327 goto out;
1328 }
1329
1330 memset(mpext, 0, sizeof(*mpext));
1331 mpext->data_seq = data_seq;
1332 mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq;
1333 mpext->data_len = copy;
1334 mpext->use_map = 1;
1335 mpext->dsn64 = 1;
1336
1337 pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d",
1338 mpext->data_seq, mpext->subflow_seq, mpext->data_len,
1339 mpext->dsn64);
1340
1341 if (zero_window_probe) {
1342 mptcp_subflow_ctx(ssk)->rel_write_seq += copy;
1343 mpext->frozen = 1;
1344 if (READ_ONCE(msk->csum_enabled))
1345 mptcp_update_data_checksum(skb, copy);
1346 tcp_push_pending_frames(ssk);
1347 return 0;
1348 }
1349out:
1350 if (READ_ONCE(msk->csum_enabled))
1351 mptcp_update_data_checksum(skb, copy);
1352 if (mptcp_subflow_ctx(ssk)->send_infinite_map)
1353 mptcp_update_infinite_map(msk, ssk, mpext);
1354 trace_mptcp_sendmsg_frag(mpext);
1355 mptcp_subflow_ctx(ssk)->rel_write_seq += copy;
1356 return copy;
1357}
1358
1359#define MPTCP_SEND_BURST_SIZE ((1 << 16) - \
1360 sizeof(struct tcphdr) - \
1361 MAX_TCP_OPTION_SPACE - \
1362 sizeof(struct ipv6hdr) - \
1363 sizeof(struct frag_hdr))
1364
1365struct subflow_send_info {
1366 struct sock *ssk;
1367 u64 linger_time;
1368};
1369
1370void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow)
1371{
1372 if (!subflow->stale)
1373 return;
1374
1375 subflow->stale = 0;
1376 MPTCP_INC_STATS(sock_net(mptcp_subflow_tcp_sock(subflow)), MPTCP_MIB_SUBFLOWRECOVER);
1377}
1378
1379bool mptcp_subflow_active(struct mptcp_subflow_context *subflow)
1380{
1381 if (unlikely(subflow->stale)) {
1382 u32 rcv_tstamp = READ_ONCE(tcp_sk(mptcp_subflow_tcp_sock(subflow))->rcv_tstamp);
1383
1384 if (subflow->stale_rcv_tstamp == rcv_tstamp)
1385 return false;
1386
1387 mptcp_subflow_set_active(subflow);
1388 }
1389 return __mptcp_subflow_active(subflow);
1390}
1391
1392#define SSK_MODE_ACTIVE 0
1393#define SSK_MODE_BACKUP 1
1394#define SSK_MODE_MAX 2
1395
1396/* implement the mptcp packet scheduler;
1397 * returns the subflow that will transmit the next DSS
1398 * additionally updates the rtx timeout
1399 */
1400static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk)
1401{
1402 struct subflow_send_info send_info[SSK_MODE_MAX];
1403 struct mptcp_subflow_context *subflow;
1404 struct sock *sk = (struct sock *)msk;
1405 u32 pace, burst, wmem;
1406 int i, nr_active = 0;
1407 struct sock *ssk;
1408 u64 linger_time;
1409 long tout = 0;
1410
1411 sock_owned_by_me(sk);
1412
1413 if (__mptcp_check_fallback(msk)) {
1414 if (!msk->first)
1415 return NULL;
1416 return __tcp_can_send(msk->first) &&
1417 sk_stream_memory_free(msk->first) ? msk->first : NULL;
1418 }
1419
1420 /* re-use last subflow, if the burst allow that */
1421 if (msk->last_snd && msk->snd_burst > 0 &&
1422 sk_stream_memory_free(msk->last_snd) &&
1423 mptcp_subflow_active(mptcp_subflow_ctx(msk->last_snd))) {
1424 mptcp_set_timeout(sk);
1425 return msk->last_snd;
1426 }
1427
1428 /* pick the subflow with the lower wmem/wspace ratio */
1429 for (i = 0; i < SSK_MODE_MAX; ++i) {
1430 send_info[i].ssk = NULL;
1431 send_info[i].linger_time = -1;
1432 }
1433
1434 mptcp_for_each_subflow(msk, subflow) {
1435 trace_mptcp_subflow_get_send(subflow);
1436 ssk = mptcp_subflow_tcp_sock(subflow);
1437 if (!mptcp_subflow_active(subflow))
1438 continue;
1439
1440 tout = max(tout, mptcp_timeout_from_subflow(subflow));
1441 nr_active += !subflow->backup;
1442 pace = subflow->avg_pacing_rate;
1443 if (unlikely(!pace)) {
1444 /* init pacing rate from socket */
1445 subflow->avg_pacing_rate = READ_ONCE(ssk->sk_pacing_rate);
1446 pace = subflow->avg_pacing_rate;
1447 if (!pace)
1448 continue;
1449 }
1450
1451 linger_time = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32, pace);
1452 if (linger_time < send_info[subflow->backup].linger_time) {
1453 send_info[subflow->backup].ssk = ssk;
1454 send_info[subflow->backup].linger_time = linger_time;
1455 }
1456 }
1457 __mptcp_set_timeout(sk, tout);
1458
1459 /* pick the best backup if no other subflow is active */
1460 if (!nr_active)
1461 send_info[SSK_MODE_ACTIVE].ssk = send_info[SSK_MODE_BACKUP].ssk;
1462
1463 /* According to the blest algorithm, to avoid HoL blocking for the
1464 * faster flow, we need to:
1465 * - estimate the faster flow linger time
1466 * - use the above to estimate the amount of byte transferred
1467 * by the faster flow
1468 * - check that the amount of queued data is greter than the above,
1469 * otherwise do not use the picked, slower, subflow
1470 * We select the subflow with the shorter estimated time to flush
1471 * the queued mem, which basically ensure the above. We just need
1472 * to check that subflow has a non empty cwin.
1473 */
1474 ssk = send_info[SSK_MODE_ACTIVE].ssk;
1475 if (!ssk || !sk_stream_memory_free(ssk))
1476 return NULL;
1477
1478 burst = min_t(int, MPTCP_SEND_BURST_SIZE, mptcp_wnd_end(msk) - msk->snd_nxt);
1479 wmem = READ_ONCE(ssk->sk_wmem_queued);
1480 if (!burst) {
1481 msk->last_snd = NULL;
1482 return ssk;
1483 }
1484
1485 subflow = mptcp_subflow_ctx(ssk);
1486 subflow->avg_pacing_rate = div_u64((u64)subflow->avg_pacing_rate * wmem +
1487 READ_ONCE(ssk->sk_pacing_rate) * burst,
1488 burst + wmem);
1489 msk->last_snd = ssk;
1490 msk->snd_burst = burst;
1491 return ssk;
1492}
1493
1494static void mptcp_push_release(struct sock *ssk, struct mptcp_sendmsg_info *info)
1495{
1496 tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal);
1497 release_sock(ssk);
1498}
1499
1500static void mptcp_update_post_push(struct mptcp_sock *msk,
1501 struct mptcp_data_frag *dfrag,
1502 u32 sent)
1503{
1504 u64 snd_nxt_new = dfrag->data_seq;
1505
1506 dfrag->already_sent += sent;
1507
1508 msk->snd_burst -= sent;
1509
1510 snd_nxt_new += dfrag->already_sent;
1511
1512 /* snd_nxt_new can be smaller than snd_nxt in case mptcp
1513 * is recovering after a failover. In that event, this re-sends
1514 * old segments.
1515 *
1516 * Thus compute snd_nxt_new candidate based on
1517 * the dfrag->data_seq that was sent and the data
1518 * that has been handed to the subflow for transmission
1519 * and skip update in case it was old dfrag.
1520 */
1521 if (likely(after64(snd_nxt_new, msk->snd_nxt)))
1522 msk->snd_nxt = snd_nxt_new;
1523}
1524
1525void mptcp_check_and_set_pending(struct sock *sk)
1526{
1527 if (mptcp_send_head(sk))
1528 mptcp_sk(sk)->push_pending |= BIT(MPTCP_PUSH_PENDING);
1529}
1530
1531void __mptcp_push_pending(struct sock *sk, unsigned int flags)
1532{
1533 struct sock *prev_ssk = NULL, *ssk = NULL;
1534 struct mptcp_sock *msk = mptcp_sk(sk);
1535 struct mptcp_sendmsg_info info = {
1536 .flags = flags,
1537 };
1538 bool do_check_data_fin = false;
1539 struct mptcp_data_frag *dfrag;
1540 int len;
1541
1542 while ((dfrag = mptcp_send_head(sk))) {
1543 info.sent = dfrag->already_sent;
1544 info.limit = dfrag->data_len;
1545 len = dfrag->data_len - dfrag->already_sent;
1546 while (len > 0) {
1547 int ret = 0;
1548
1549 prev_ssk = ssk;
1550 ssk = mptcp_subflow_get_send(msk);
1551
1552 /* First check. If the ssk has changed since
1553 * the last round, release prev_ssk
1554 */
1555 if (ssk != prev_ssk && prev_ssk)
1556 mptcp_push_release(prev_ssk, &info);
1557 if (!ssk)
1558 goto out;
1559
1560 /* Need to lock the new subflow only if different
1561 * from the previous one, otherwise we are still
1562 * helding the relevant lock
1563 */
1564 if (ssk != prev_ssk)
1565 lock_sock(ssk);
1566
1567 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
1568 if (ret <= 0) {
1569 if (ret == -EAGAIN)
1570 continue;
1571 mptcp_push_release(ssk, &info);
1572 goto out;
1573 }
1574
1575 do_check_data_fin = true;
1576 info.sent += ret;
1577 len -= ret;
1578
1579 mptcp_update_post_push(msk, dfrag, ret);
1580 }
1581 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1582 }
1583
1584 /* at this point we held the socket lock for the last subflow we used */
1585 if (ssk)
1586 mptcp_push_release(ssk, &info);
1587
1588out:
1589 /* ensure the rtx timer is running */
1590 if (!mptcp_timer_pending(sk))
1591 mptcp_reset_timer(sk);
1592 if (do_check_data_fin)
1593 __mptcp_check_send_data_fin(sk);
1594}
1595
1596static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk, bool first)
1597{
1598 struct mptcp_sock *msk = mptcp_sk(sk);
1599 struct mptcp_sendmsg_info info = {
1600 .data_lock_held = true,
1601 };
1602 struct mptcp_data_frag *dfrag;
1603 struct sock *xmit_ssk;
1604 int len, copied = 0;
1605
1606 info.flags = 0;
1607 while ((dfrag = mptcp_send_head(sk))) {
1608 info.sent = dfrag->already_sent;
1609 info.limit = dfrag->data_len;
1610 len = dfrag->data_len - dfrag->already_sent;
1611 while (len > 0) {
1612 int ret = 0;
1613
1614 /* check for a different subflow usage only after
1615 * spooling the first chunk of data
1616 */
1617 xmit_ssk = first ? ssk : mptcp_subflow_get_send(msk);
1618 if (!xmit_ssk)
1619 goto out;
1620 if (xmit_ssk != ssk) {
1621 mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk),
1622 MPTCP_DELEGATE_SEND);
1623 goto out;
1624 }
1625
1626 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
1627 if (ret <= 0)
1628 goto out;
1629
1630 info.sent += ret;
1631 copied += ret;
1632 len -= ret;
1633 first = false;
1634
1635 mptcp_update_post_push(msk, dfrag, ret);
1636 }
1637 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1638 }
1639
1640out:
1641 /* __mptcp_alloc_tx_skb could have released some wmem and we are
1642 * not going to flush it via release_sock()
1643 */
1644 if (copied) {
1645 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
1646 info.size_goal);
1647 if (!mptcp_timer_pending(sk))
1648 mptcp_reset_timer(sk);
1649
1650 if (msk->snd_data_fin_enable &&
1651 msk->snd_nxt + 1 == msk->write_seq)
1652 mptcp_schedule_work(sk);
1653 }
1654}
1655
1656static void mptcp_set_nospace(struct sock *sk)
1657{
1658 /* enable autotune */
1659 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1660
1661 /* will be cleared on avail space */
1662 set_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags);
1663}
1664
1665static int mptcp_disconnect(struct sock *sk, int flags);
1666
1667static int mptcp_sendmsg_fastopen(struct sock *sk, struct sock *ssk, struct msghdr *msg,
1668 size_t len, int *copied_syn)
1669{
1670 unsigned int saved_flags = msg->msg_flags;
1671 struct mptcp_sock *msk = mptcp_sk(sk);
1672 int ret;
1673
1674 lock_sock(ssk);
1675 msg->msg_flags |= MSG_DONTWAIT;
1676 msk->connect_flags = O_NONBLOCK;
1677 msk->fastopening = 1;
1678 ret = tcp_sendmsg_fastopen(ssk, msg, copied_syn, len, NULL);
1679 msk->fastopening = 0;
1680 msg->msg_flags = saved_flags;
1681 release_sock(ssk);
1682
1683 /* do the blocking bits of inet_stream_connect outside the ssk socket lock */
1684 if (ret == -EINPROGRESS && !(msg->msg_flags & MSG_DONTWAIT)) {
1685 ret = __inet_stream_connect(sk->sk_socket, msg->msg_name,
1686 msg->msg_namelen, msg->msg_flags, 1);
1687
1688 /* Keep the same behaviour of plain TCP: zero the copied bytes in
1689 * case of any error, except timeout or signal
1690 */
1691 if (ret && ret != -EINPROGRESS && ret != -ERESTARTSYS && ret != -EINTR)
1692 *copied_syn = 0;
1693 } else if (ret && ret != -EINPROGRESS) {
1694 mptcp_disconnect(sk, 0);
1695 }
1696
1697 return ret;
1698}
1699
1700static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
1701{
1702 struct mptcp_sock *msk = mptcp_sk(sk);
1703 struct page_frag *pfrag;
1704 struct socket *ssock;
1705 size_t copied = 0;
1706 int ret = 0;
1707 long timeo;
1708
1709 /* silently ignore everything else */
1710 msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | MSG_FASTOPEN;
1711
1712 lock_sock(sk);
1713
1714 ssock = __mptcp_nmpc_socket(msk);
1715 if (unlikely(ssock && (inet_sk(ssock->sk)->defer_connect ||
1716 msg->msg_flags & MSG_FASTOPEN))) {
1717 int copied_syn = 0;
1718
1719 ret = mptcp_sendmsg_fastopen(sk, ssock->sk, msg, len, &copied_syn);
1720 copied += copied_syn;
1721 if (ret == -EINPROGRESS && copied_syn > 0)
1722 goto out;
1723 else if (ret)
1724 goto do_error;
1725 }
1726
1727 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1728
1729 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
1730 ret = sk_stream_wait_connect(sk, &timeo);
1731 if (ret)
1732 goto do_error;
1733 }
1734
1735 ret = -EPIPE;
1736 if (unlikely(sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)))
1737 goto do_error;
1738
1739 pfrag = sk_page_frag(sk);
1740
1741 while (msg_data_left(msg)) {
1742 int total_ts, frag_truesize = 0;
1743 struct mptcp_data_frag *dfrag;
1744 bool dfrag_collapsed;
1745 size_t psize, offset;
1746
1747 /* reuse tail pfrag, if possible, or carve a new one from the
1748 * page allocator
1749 */
1750 dfrag = mptcp_pending_tail(sk);
1751 dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag);
1752 if (!dfrag_collapsed) {
1753 if (!sk_stream_memory_free(sk))
1754 goto wait_for_memory;
1755
1756 if (!mptcp_page_frag_refill(sk, pfrag))
1757 goto wait_for_memory;
1758
1759 dfrag = mptcp_carve_data_frag(msk, pfrag, pfrag->offset);
1760 frag_truesize = dfrag->overhead;
1761 }
1762
1763 /* we do not bound vs wspace, to allow a single packet.
1764 * memory accounting will prevent execessive memory usage
1765 * anyway
1766 */
1767 offset = dfrag->offset + dfrag->data_len;
1768 psize = pfrag->size - offset;
1769 psize = min_t(size_t, psize, msg_data_left(msg));
1770 total_ts = psize + frag_truesize;
1771
1772 if (!sk_wmem_schedule(sk, total_ts))
1773 goto wait_for_memory;
1774
1775 if (copy_page_from_iter(dfrag->page, offset, psize,
1776 &msg->msg_iter) != psize) {
1777 ret = -EFAULT;
1778 goto do_error;
1779 }
1780
1781 /* data successfully copied into the write queue */
1782 sk->sk_forward_alloc -= total_ts;
1783 copied += psize;
1784 dfrag->data_len += psize;
1785 frag_truesize += psize;
1786 pfrag->offset += frag_truesize;
1787 WRITE_ONCE(msk->write_seq, msk->write_seq + psize);
1788
1789 /* charge data on mptcp pending queue to the msk socket
1790 * Note: we charge such data both to sk and ssk
1791 */
1792 sk_wmem_queued_add(sk, frag_truesize);
1793 if (!dfrag_collapsed) {
1794 get_page(dfrag->page);
1795 list_add_tail(&dfrag->list, &msk->rtx_queue);
1796 if (!msk->first_pending)
1797 WRITE_ONCE(msk->first_pending, dfrag);
1798 }
1799 pr_debug("msk=%p dfrag at seq=%llu len=%u sent=%u new=%d", msk,
1800 dfrag->data_seq, dfrag->data_len, dfrag->already_sent,
1801 !dfrag_collapsed);
1802
1803 continue;
1804
1805wait_for_memory:
1806 mptcp_set_nospace(sk);
1807 __mptcp_push_pending(sk, msg->msg_flags);
1808 ret = sk_stream_wait_memory(sk, &timeo);
1809 if (ret)
1810 goto do_error;
1811 }
1812
1813 if (copied)
1814 __mptcp_push_pending(sk, msg->msg_flags);
1815
1816out:
1817 release_sock(sk);
1818 return copied;
1819
1820do_error:
1821 if (copied)
1822 goto out;
1823
1824 copied = sk_stream_error(sk, msg->msg_flags, ret);
1825 goto out;
1826}
1827
1828static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk,
1829 struct msghdr *msg,
1830 size_t len, int flags,
1831 struct scm_timestamping_internal *tss,
1832 int *cmsg_flags)
1833{
1834 struct sk_buff *skb, *tmp;
1835 int copied = 0;
1836
1837 skb_queue_walk_safe(&msk->receive_queue, skb, tmp) {
1838 u32 offset = MPTCP_SKB_CB(skb)->offset;
1839 u32 data_len = skb->len - offset;
1840 u32 count = min_t(size_t, len - copied, data_len);
1841 int err;
1842
1843 if (!(flags & MSG_TRUNC)) {
1844 err = skb_copy_datagram_msg(skb, offset, msg, count);
1845 if (unlikely(err < 0)) {
1846 if (!copied)
1847 return err;
1848 break;
1849 }
1850 }
1851
1852 if (MPTCP_SKB_CB(skb)->has_rxtstamp) {
1853 tcp_update_recv_tstamps(skb, tss);
1854 *cmsg_flags |= MPTCP_CMSG_TS;
1855 }
1856
1857 copied += count;
1858
1859 if (count < data_len) {
1860 if (!(flags & MSG_PEEK)) {
1861 MPTCP_SKB_CB(skb)->offset += count;
1862 MPTCP_SKB_CB(skb)->map_seq += count;
1863 }
1864 break;
1865 }
1866
1867 if (!(flags & MSG_PEEK)) {
1868 /* we will bulk release the skb memory later */
1869 skb->destructor = NULL;
1870 WRITE_ONCE(msk->rmem_released, msk->rmem_released + skb->truesize);
1871 __skb_unlink(skb, &msk->receive_queue);
1872 __kfree_skb(skb);
1873 }
1874
1875 if (copied >= len)
1876 break;
1877 }
1878
1879 return copied;
1880}
1881
1882/* receive buffer autotuning. See tcp_rcv_space_adjust for more information.
1883 *
1884 * Only difference: Use highest rtt estimate of the subflows in use.
1885 */
1886static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied)
1887{
1888 struct mptcp_subflow_context *subflow;
1889 struct sock *sk = (struct sock *)msk;
1890 u32 time, advmss = 1;
1891 u64 rtt_us, mstamp;
1892
1893 sock_owned_by_me(sk);
1894
1895 if (copied <= 0)
1896 return;
1897
1898 msk->rcvq_space.copied += copied;
1899
1900 mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC);
1901 time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time);
1902
1903 rtt_us = msk->rcvq_space.rtt_us;
1904 if (rtt_us && time < (rtt_us >> 3))
1905 return;
1906
1907 rtt_us = 0;
1908 mptcp_for_each_subflow(msk, subflow) {
1909 const struct tcp_sock *tp;
1910 u64 sf_rtt_us;
1911 u32 sf_advmss;
1912
1913 tp = tcp_sk(mptcp_subflow_tcp_sock(subflow));
1914
1915 sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us);
1916 sf_advmss = READ_ONCE(tp->advmss);
1917
1918 rtt_us = max(sf_rtt_us, rtt_us);
1919 advmss = max(sf_advmss, advmss);
1920 }
1921
1922 msk->rcvq_space.rtt_us = rtt_us;
1923 if (time < (rtt_us >> 3) || rtt_us == 0)
1924 return;
1925
1926 if (msk->rcvq_space.copied <= msk->rcvq_space.space)
1927 goto new_measure;
1928
1929 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf) &&
1930 !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
1931 int rcvmem, rcvbuf;
1932 u64 rcvwin, grow;
1933
1934 rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss;
1935
1936 grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space);
1937
1938 do_div(grow, msk->rcvq_space.space);
1939 rcvwin += (grow << 1);
1940
1941 rcvmem = SKB_TRUESIZE(advmss + MAX_TCP_HEADER);
1942 while (tcp_win_from_space(sk, rcvmem) < advmss)
1943 rcvmem += 128;
1944
1945 do_div(rcvwin, advmss);
1946 rcvbuf = min_t(u64, rcvwin * rcvmem,
1947 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[2]));
1948
1949 if (rcvbuf > sk->sk_rcvbuf) {
1950 u32 window_clamp;
1951
1952 window_clamp = tcp_win_from_space(sk, rcvbuf);
1953 WRITE_ONCE(sk->sk_rcvbuf, rcvbuf);
1954
1955 /* Make subflows follow along. If we do not do this, we
1956 * get drops at subflow level if skbs can't be moved to
1957 * the mptcp rx queue fast enough (announced rcv_win can
1958 * exceed ssk->sk_rcvbuf).
1959 */
1960 mptcp_for_each_subflow(msk, subflow) {
1961 struct sock *ssk;
1962 bool slow;
1963
1964 ssk = mptcp_subflow_tcp_sock(subflow);
1965 slow = lock_sock_fast(ssk);
1966 WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf);
1967 tcp_sk(ssk)->window_clamp = window_clamp;
1968 tcp_cleanup_rbuf(ssk, 1);
1969 unlock_sock_fast(ssk, slow);
1970 }
1971 }
1972 }
1973
1974 msk->rcvq_space.space = msk->rcvq_space.copied;
1975new_measure:
1976 msk->rcvq_space.copied = 0;
1977 msk->rcvq_space.time = mstamp;
1978}
1979
1980static void __mptcp_update_rmem(struct sock *sk)
1981{
1982 struct mptcp_sock *msk = mptcp_sk(sk);
1983
1984 if (!msk->rmem_released)
1985 return;
1986
1987 atomic_sub(msk->rmem_released, &sk->sk_rmem_alloc);
1988 mptcp_rmem_uncharge(sk, msk->rmem_released);
1989 WRITE_ONCE(msk->rmem_released, 0);
1990}
1991
1992static void __mptcp_splice_receive_queue(struct sock *sk)
1993{
1994 struct mptcp_sock *msk = mptcp_sk(sk);
1995
1996 skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue);
1997}
1998
1999static bool __mptcp_move_skbs(struct mptcp_sock *msk)
2000{
2001 struct sock *sk = (struct sock *)msk;
2002 unsigned int moved = 0;
2003 bool ret, done;
2004
2005 do {
2006 struct sock *ssk = mptcp_subflow_recv_lookup(msk);
2007 bool slowpath;
2008
2009 /* we can have data pending in the subflows only if the msk
2010 * receive buffer was full at subflow_data_ready() time,
2011 * that is an unlikely slow path.
2012 */
2013 if (likely(!ssk))
2014 break;
2015
2016 slowpath = lock_sock_fast(ssk);
2017 mptcp_data_lock(sk);
2018 __mptcp_update_rmem(sk);
2019 done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
2020 mptcp_data_unlock(sk);
2021
2022 if (unlikely(ssk->sk_err))
2023 __mptcp_error_report(sk);
2024 unlock_sock_fast(ssk, slowpath);
2025 } while (!done);
2026
2027 /* acquire the data lock only if some input data is pending */
2028 ret = moved > 0;
2029 if (!RB_EMPTY_ROOT(&msk->out_of_order_queue) ||
2030 !skb_queue_empty_lockless(&sk->sk_receive_queue)) {
2031 mptcp_data_lock(sk);
2032 __mptcp_update_rmem(sk);
2033 ret |= __mptcp_ofo_queue(msk);
2034 __mptcp_splice_receive_queue(sk);
2035 mptcp_data_unlock(sk);
2036 }
2037 if (ret)
2038 mptcp_check_data_fin((struct sock *)msk);
2039 return !skb_queue_empty(&msk->receive_queue);
2040}
2041
2042static unsigned int mptcp_inq_hint(const struct sock *sk)
2043{
2044 const struct mptcp_sock *msk = mptcp_sk(sk);
2045 const struct sk_buff *skb;
2046
2047 skb = skb_peek(&msk->receive_queue);
2048 if (skb) {
2049 u64 hint_val = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq;
2050
2051 if (hint_val >= INT_MAX)
2052 return INT_MAX;
2053
2054 return (unsigned int)hint_val;
2055 }
2056
2057 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
2058 return 1;
2059
2060 return 0;
2061}
2062
2063static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
2064 int flags, int *addr_len)
2065{
2066 struct mptcp_sock *msk = mptcp_sk(sk);
2067 struct scm_timestamping_internal tss;
2068 int copied = 0, cmsg_flags = 0;
2069 int target;
2070 long timeo;
2071
2072 /* MSG_ERRQUEUE is really a no-op till we support IP_RECVERR */
2073 if (unlikely(flags & MSG_ERRQUEUE))
2074 return inet_recv_error(sk, msg, len, addr_len);
2075
2076 lock_sock(sk);
2077 if (unlikely(sk->sk_state == TCP_LISTEN)) {
2078 copied = -ENOTCONN;
2079 goto out_err;
2080 }
2081
2082 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2083
2084 len = min_t(size_t, len, INT_MAX);
2085 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
2086
2087 if (unlikely(msk->recvmsg_inq))
2088 cmsg_flags = MPTCP_CMSG_INQ;
2089
2090 while (copied < len) {
2091 int bytes_read;
2092
2093 bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags, &tss, &cmsg_flags);
2094 if (unlikely(bytes_read < 0)) {
2095 if (!copied)
2096 copied = bytes_read;
2097 goto out_err;
2098 }
2099
2100 copied += bytes_read;
2101
2102 /* be sure to advertise window change */
2103 mptcp_cleanup_rbuf(msk);
2104
2105 if (skb_queue_empty(&msk->receive_queue) && __mptcp_move_skbs(msk))
2106 continue;
2107
2108 /* only the master socket status is relevant here. The exit
2109 * conditions mirror closely tcp_recvmsg()
2110 */
2111 if (copied >= target)
2112 break;
2113
2114 if (copied) {
2115 if (sk->sk_err ||
2116 sk->sk_state == TCP_CLOSE ||
2117 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2118 !timeo ||
2119 signal_pending(current))
2120 break;
2121 } else {
2122 if (sk->sk_err) {
2123 copied = sock_error(sk);
2124 break;
2125 }
2126
2127 if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
2128 mptcp_check_for_eof(msk);
2129
2130 if (sk->sk_shutdown & RCV_SHUTDOWN) {
2131 /* race breaker: the shutdown could be after the
2132 * previous receive queue check
2133 */
2134 if (__mptcp_move_skbs(msk))
2135 continue;
2136 break;
2137 }
2138
2139 if (sk->sk_state == TCP_CLOSE) {
2140 copied = -ENOTCONN;
2141 break;
2142 }
2143
2144 if (!timeo) {
2145 copied = -EAGAIN;
2146 break;
2147 }
2148
2149 if (signal_pending(current)) {
2150 copied = sock_intr_errno(timeo);
2151 break;
2152 }
2153 }
2154
2155 pr_debug("block timeout %ld", timeo);
2156 sk_wait_data(sk, &timeo, NULL);
2157 }
2158
2159out_err:
2160 if (cmsg_flags && copied >= 0) {
2161 if (cmsg_flags & MPTCP_CMSG_TS)
2162 tcp_recv_timestamp(msg, sk, &tss);
2163
2164 if (cmsg_flags & MPTCP_CMSG_INQ) {
2165 unsigned int inq = mptcp_inq_hint(sk);
2166
2167 put_cmsg(msg, SOL_TCP, TCP_CM_INQ, sizeof(inq), &inq);
2168 }
2169 }
2170
2171 pr_debug("msk=%p rx queue empty=%d:%d copied=%d",
2172 msk, skb_queue_empty_lockless(&sk->sk_receive_queue),
2173 skb_queue_empty(&msk->receive_queue), copied);
2174 if (!(flags & MSG_PEEK))
2175 mptcp_rcv_space_adjust(msk, copied);
2176
2177 release_sock(sk);
2178 return copied;
2179}
2180
2181static void mptcp_retransmit_timer(struct timer_list *t)
2182{
2183 struct inet_connection_sock *icsk = from_timer(icsk, t,
2184 icsk_retransmit_timer);
2185 struct sock *sk = &icsk->icsk_inet.sk;
2186 struct mptcp_sock *msk = mptcp_sk(sk);
2187
2188 bh_lock_sock(sk);
2189 if (!sock_owned_by_user(sk)) {
2190 /* we need a process context to retransmit */
2191 if (!test_and_set_bit(MPTCP_WORK_RTX, &msk->flags))
2192 mptcp_schedule_work(sk);
2193 } else {
2194 /* delegate our work to tcp_release_cb() */
2195 __set_bit(MPTCP_RETRANSMIT, &msk->cb_flags);
2196 }
2197 bh_unlock_sock(sk);
2198 sock_put(sk);
2199}
2200
2201static void mptcp_timeout_timer(struct timer_list *t)
2202{
2203 struct sock *sk = from_timer(sk, t, sk_timer);
2204
2205 mptcp_schedule_work(sk);
2206 sock_put(sk);
2207}
2208
2209/* Find an idle subflow. Return NULL if there is unacked data at tcp
2210 * level.
2211 *
2212 * A backup subflow is returned only if that is the only kind available.
2213 */
2214static struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk)
2215{
2216 struct sock *backup = NULL, *pick = NULL;
2217 struct mptcp_subflow_context *subflow;
2218 int min_stale_count = INT_MAX;
2219
2220 sock_owned_by_me((const struct sock *)msk);
2221
2222 if (__mptcp_check_fallback(msk))
2223 return NULL;
2224
2225 mptcp_for_each_subflow(msk, subflow) {
2226 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2227
2228 if (!__mptcp_subflow_active(subflow))
2229 continue;
2230
2231 /* still data outstanding at TCP level? skip this */
2232 if (!tcp_rtx_and_write_queues_empty(ssk)) {
2233 mptcp_pm_subflow_chk_stale(msk, ssk);
2234 min_stale_count = min_t(int, min_stale_count, subflow->stale_count);
2235 continue;
2236 }
2237
2238 if (subflow->backup) {
2239 if (!backup)
2240 backup = ssk;
2241 continue;
2242 }
2243
2244 if (!pick)
2245 pick = ssk;
2246 }
2247
2248 if (pick)
2249 return pick;
2250
2251 /* use backup only if there are no progresses anywhere */
2252 return min_stale_count > 1 ? backup : NULL;
2253}
2254
2255static void mptcp_dispose_initial_subflow(struct mptcp_sock *msk)
2256{
2257 if (msk->subflow) {
2258 iput(SOCK_INODE(msk->subflow));
2259 msk->subflow = NULL;
2260 }
2261}
2262
2263bool __mptcp_retransmit_pending_data(struct sock *sk)
2264{
2265 struct mptcp_data_frag *cur, *rtx_head;
2266 struct mptcp_sock *msk = mptcp_sk(sk);
2267
2268 if (__mptcp_check_fallback(msk))
2269 return false;
2270
2271 if (tcp_rtx_and_write_queues_empty(sk))
2272 return false;
2273
2274 /* the closing socket has some data untransmitted and/or unacked:
2275 * some data in the mptcp rtx queue has not really xmitted yet.
2276 * keep it simple and re-inject the whole mptcp level rtx queue
2277 */
2278 mptcp_data_lock(sk);
2279 __mptcp_clean_una_wakeup(sk);
2280 rtx_head = mptcp_rtx_head(sk);
2281 if (!rtx_head) {
2282 mptcp_data_unlock(sk);
2283 return false;
2284 }
2285
2286 msk->recovery_snd_nxt = msk->snd_nxt;
2287 msk->recovery = true;
2288 mptcp_data_unlock(sk);
2289
2290 msk->first_pending = rtx_head;
2291 msk->snd_burst = 0;
2292
2293 /* be sure to clear the "sent status" on all re-injected fragments */
2294 list_for_each_entry(cur, &msk->rtx_queue, list) {
2295 if (!cur->already_sent)
2296 break;
2297 cur->already_sent = 0;
2298 }
2299
2300 return true;
2301}
2302
2303/* flags for __mptcp_close_ssk() */
2304#define MPTCP_CF_PUSH BIT(1)
2305#define MPTCP_CF_FASTCLOSE BIT(2)
2306
2307/* subflow sockets can be either outgoing (connect) or incoming
2308 * (accept).
2309 *
2310 * Outgoing subflows use in-kernel sockets.
2311 * Incoming subflows do not have their own 'struct socket' allocated,
2312 * so we need to use tcp_close() after detaching them from the mptcp
2313 * parent socket.
2314 */
2315static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
2316 struct mptcp_subflow_context *subflow,
2317 unsigned int flags)
2318{
2319 struct mptcp_sock *msk = mptcp_sk(sk);
2320 bool need_push, dispose_it;
2321
2322 dispose_it = !msk->subflow || ssk != msk->subflow->sk;
2323 if (dispose_it)
2324 list_del(&subflow->node);
2325
2326 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
2327
2328 if (flags & MPTCP_CF_FASTCLOSE) {
2329 /* be sure to force the tcp_disconnect() path,
2330 * to generate the egress reset
2331 */
2332 ssk->sk_lingertime = 0;
2333 sock_set_flag(ssk, SOCK_LINGER);
2334 subflow->send_fastclose = 1;
2335 }
2336
2337 need_push = (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(sk);
2338 if (!dispose_it) {
2339 tcp_disconnect(ssk, 0);
2340 msk->subflow->state = SS_UNCONNECTED;
2341 mptcp_subflow_ctx_reset(subflow);
2342 release_sock(ssk);
2343
2344 goto out;
2345 }
2346
2347 sock_orphan(ssk);
2348 subflow->disposable = 1;
2349
2350 /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops
2351 * the ssk has been already destroyed, we just need to release the
2352 * reference owned by msk;
2353 */
2354 if (!inet_csk(ssk)->icsk_ulp_ops) {
2355 kfree_rcu(subflow, rcu);
2356 } else {
2357 /* otherwise tcp will dispose of the ssk and subflow ctx */
2358 if (ssk->sk_state == TCP_LISTEN) {
2359 tcp_set_state(ssk, TCP_CLOSE);
2360 mptcp_subflow_queue_clean(sk, ssk);
2361 inet_csk_listen_stop(ssk);
2362 mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CLOSED);
2363 }
2364 __tcp_close(ssk, 0);
2365
2366 /* close acquired an extra ref */
2367 __sock_put(ssk);
2368 }
2369 release_sock(ssk);
2370
2371 sock_put(ssk);
2372
2373 if (ssk == msk->first)
2374 msk->first = NULL;
2375
2376out:
2377 if (ssk == msk->last_snd)
2378 msk->last_snd = NULL;
2379
2380 if (need_push)
2381 __mptcp_push_pending(sk, 0);
2382}
2383
2384void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
2385 struct mptcp_subflow_context *subflow)
2386{
2387 if (sk->sk_state == TCP_ESTABLISHED)
2388 mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL);
2389
2390 /* subflow aborted before reaching the fully_established status
2391 * attempt the creation of the next subflow
2392 */
2393 mptcp_pm_subflow_check_next(mptcp_sk(sk), ssk, subflow);
2394
2395 __mptcp_close_ssk(sk, ssk, subflow, MPTCP_CF_PUSH);
2396}
2397
2398static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu)
2399{
2400 return 0;
2401}
2402
2403static void __mptcp_close_subflow(struct mptcp_sock *msk)
2404{
2405 struct mptcp_subflow_context *subflow, *tmp;
2406
2407 might_sleep();
2408
2409 mptcp_for_each_subflow_safe(msk, subflow, tmp) {
2410 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2411
2412 if (inet_sk_state_load(ssk) != TCP_CLOSE)
2413 continue;
2414
2415 /* 'subflow_data_ready' will re-sched once rx queue is empty */
2416 if (!skb_queue_empty_lockless(&ssk->sk_receive_queue))
2417 continue;
2418
2419 mptcp_close_ssk((struct sock *)msk, ssk, subflow);
2420 }
2421}
2422
2423static bool mptcp_check_close_timeout(const struct sock *sk)
2424{
2425 s32 delta = tcp_jiffies32 - inet_csk(sk)->icsk_mtup.probe_timestamp;
2426 struct mptcp_subflow_context *subflow;
2427
2428 if (delta >= TCP_TIMEWAIT_LEN)
2429 return true;
2430
2431 /* if all subflows are in closed status don't bother with additional
2432 * timeout
2433 */
2434 mptcp_for_each_subflow(mptcp_sk(sk), subflow) {
2435 if (inet_sk_state_load(mptcp_subflow_tcp_sock(subflow)) !=
2436 TCP_CLOSE)
2437 return false;
2438 }
2439 return true;
2440}
2441
2442static void mptcp_check_fastclose(struct mptcp_sock *msk)
2443{
2444 struct mptcp_subflow_context *subflow, *tmp;
2445 struct sock *sk = (struct sock *)msk;
2446
2447 if (likely(!READ_ONCE(msk->rcv_fastclose)))
2448 return;
2449
2450 mptcp_token_destroy(msk);
2451
2452 mptcp_for_each_subflow_safe(msk, subflow, tmp) {
2453 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
2454 bool slow;
2455
2456 slow = lock_sock_fast(tcp_sk);
2457 if (tcp_sk->sk_state != TCP_CLOSE) {
2458 tcp_send_active_reset(tcp_sk, GFP_ATOMIC);
2459 tcp_set_state(tcp_sk, TCP_CLOSE);
2460 }
2461 unlock_sock_fast(tcp_sk, slow);
2462 }
2463
2464 /* Mirror the tcp_reset() error propagation */
2465 switch (sk->sk_state) {
2466 case TCP_SYN_SENT:
2467 sk->sk_err = ECONNREFUSED;
2468 break;
2469 case TCP_CLOSE_WAIT:
2470 sk->sk_err = EPIPE;
2471 break;
2472 case TCP_CLOSE:
2473 return;
2474 default:
2475 sk->sk_err = ECONNRESET;
2476 }
2477
2478 inet_sk_state_store(sk, TCP_CLOSE);
2479 sk->sk_shutdown = SHUTDOWN_MASK;
2480 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
2481 set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags);
2482
2483 /* the calling mptcp_worker will properly destroy the socket */
2484 if (sock_flag(sk, SOCK_DEAD))
2485 return;
2486
2487 sk->sk_state_change(sk);
2488 sk_error_report(sk);
2489}
2490
2491static void __mptcp_retrans(struct sock *sk)
2492{
2493 struct mptcp_sock *msk = mptcp_sk(sk);
2494 struct mptcp_sendmsg_info info = {};
2495 struct mptcp_data_frag *dfrag;
2496 size_t copied = 0;
2497 struct sock *ssk;
2498 int ret;
2499
2500 mptcp_clean_una_wakeup(sk);
2501
2502 /* first check ssk: need to kick "stale" logic */
2503 ssk = mptcp_subflow_get_retrans(msk);
2504 dfrag = mptcp_rtx_head(sk);
2505 if (!dfrag) {
2506 if (mptcp_data_fin_enabled(msk)) {
2507 struct inet_connection_sock *icsk = inet_csk(sk);
2508
2509 icsk->icsk_retransmits++;
2510 mptcp_set_datafin_timeout(sk);
2511 mptcp_send_ack(msk);
2512
2513 goto reset_timer;
2514 }
2515
2516 if (!mptcp_send_head(sk))
2517 return;
2518
2519 goto reset_timer;
2520 }
2521
2522 if (!ssk)
2523 goto reset_timer;
2524
2525 lock_sock(ssk);
2526
2527 /* limit retransmission to the bytes already sent on some subflows */
2528 info.sent = 0;
2529 info.limit = READ_ONCE(msk->csum_enabled) ? dfrag->data_len : dfrag->already_sent;
2530 while (info.sent < info.limit) {
2531 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
2532 if (ret <= 0)
2533 break;
2534
2535 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS);
2536 copied += ret;
2537 info.sent += ret;
2538 }
2539 if (copied) {
2540 dfrag->already_sent = max(dfrag->already_sent, info.sent);
2541 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
2542 info.size_goal);
2543 WRITE_ONCE(msk->allow_infinite_fallback, false);
2544 }
2545
2546 release_sock(ssk);
2547
2548reset_timer:
2549 mptcp_check_and_set_pending(sk);
2550
2551 if (!mptcp_timer_pending(sk))
2552 mptcp_reset_timer(sk);
2553}
2554
2555/* schedule the timeout timer for the relevant event: either close timeout
2556 * or mp_fail timeout. The close timeout takes precedence on the mp_fail one
2557 */
2558void mptcp_reset_timeout(struct mptcp_sock *msk, unsigned long fail_tout)
2559{
2560 struct sock *sk = (struct sock *)msk;
2561 unsigned long timeout, close_timeout;
2562
2563 if (!fail_tout && !sock_flag(sk, SOCK_DEAD))
2564 return;
2565
2566 close_timeout = inet_csk(sk)->icsk_mtup.probe_timestamp - tcp_jiffies32 + jiffies + TCP_TIMEWAIT_LEN;
2567
2568 /* the close timeout takes precedence on the fail one, and here at least one of
2569 * them is active
2570 */
2571 timeout = sock_flag(sk, SOCK_DEAD) ? close_timeout : fail_tout;
2572
2573 sk_reset_timer(sk, &sk->sk_timer, timeout);
2574}
2575
2576static void mptcp_mp_fail_no_response(struct mptcp_sock *msk)
2577{
2578 struct sock *ssk = msk->first;
2579 bool slow;
2580
2581 if (!ssk)
2582 return;
2583
2584 pr_debug("MP_FAIL doesn't respond, reset the subflow");
2585
2586 slow = lock_sock_fast(ssk);
2587 mptcp_subflow_reset(ssk);
2588 WRITE_ONCE(mptcp_subflow_ctx(ssk)->fail_tout, 0);
2589 unlock_sock_fast(ssk, slow);
2590
2591 mptcp_reset_timeout(msk, 0);
2592}
2593
2594static void mptcp_do_fastclose(struct sock *sk)
2595{
2596 struct mptcp_subflow_context *subflow, *tmp;
2597 struct mptcp_sock *msk = mptcp_sk(sk);
2598
2599 mptcp_for_each_subflow_safe(msk, subflow, tmp)
2600 __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow),
2601 subflow, MPTCP_CF_FASTCLOSE);
2602}
2603
2604static void mptcp_worker(struct work_struct *work)
2605{
2606 struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
2607 struct sock *sk = (struct sock *)msk;
2608 unsigned long fail_tout;
2609 int state;
2610
2611 lock_sock(sk);
2612 state = sk->sk_state;
2613 if (unlikely(state == TCP_CLOSE))
2614 goto unlock;
2615
2616 mptcp_check_data_fin_ack(sk);
2617
2618 mptcp_check_fastclose(msk);
2619
2620 mptcp_pm_nl_work(msk);
2621
2622 if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
2623 mptcp_check_for_eof(msk);
2624
2625 __mptcp_check_send_data_fin(sk);
2626 mptcp_check_data_fin(sk);
2627
2628 /* There is no point in keeping around an orphaned sk timedout or
2629 * closed, but we need the msk around to reply to incoming DATA_FIN,
2630 * even if it is orphaned and in FIN_WAIT2 state
2631 */
2632 if (sock_flag(sk, SOCK_DEAD)) {
2633 if (mptcp_check_close_timeout(sk)) {
2634 inet_sk_state_store(sk, TCP_CLOSE);
2635 mptcp_do_fastclose(sk);
2636 }
2637 if (sk->sk_state == TCP_CLOSE) {
2638 __mptcp_destroy_sock(sk);
2639 goto unlock;
2640 }
2641 }
2642
2643 if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
2644 __mptcp_close_subflow(msk);
2645
2646 if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
2647 __mptcp_retrans(sk);
2648
2649 fail_tout = msk->first ? READ_ONCE(mptcp_subflow_ctx(msk->first)->fail_tout) : 0;
2650 if (fail_tout && time_after(jiffies, fail_tout))
2651 mptcp_mp_fail_no_response(msk);
2652
2653unlock:
2654 release_sock(sk);
2655 sock_put(sk);
2656}
2657
2658static int __mptcp_init_sock(struct sock *sk)
2659{
2660 struct mptcp_sock *msk = mptcp_sk(sk);
2661
2662 INIT_LIST_HEAD(&msk->conn_list);
2663 INIT_LIST_HEAD(&msk->join_list);
2664 INIT_LIST_HEAD(&msk->rtx_queue);
2665 INIT_WORK(&msk->work, mptcp_worker);
2666 __skb_queue_head_init(&msk->receive_queue);
2667 msk->out_of_order_queue = RB_ROOT;
2668 msk->first_pending = NULL;
2669 msk->rmem_fwd_alloc = 0;
2670 WRITE_ONCE(msk->rmem_released, 0);
2671 msk->timer_ival = TCP_RTO_MIN;
2672
2673 msk->first = NULL;
2674 inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss;
2675 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
2676 WRITE_ONCE(msk->allow_infinite_fallback, true);
2677 msk->recovery = false;
2678
2679 mptcp_pm_data_init(msk);
2680
2681 /* re-use the csk retrans timer for MPTCP-level retrans */
2682 timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0);
2683 timer_setup(&sk->sk_timer, mptcp_timeout_timer, 0);
2684
2685 return 0;
2686}
2687
2688static void mptcp_ca_reset(struct sock *sk)
2689{
2690 struct inet_connection_sock *icsk = inet_csk(sk);
2691
2692 tcp_assign_congestion_control(sk);
2693 strcpy(mptcp_sk(sk)->ca_name, icsk->icsk_ca_ops->name);
2694
2695 /* no need to keep a reference to the ops, the name will suffice */
2696 tcp_cleanup_congestion_control(sk);
2697 icsk->icsk_ca_ops = NULL;
2698}
2699
2700static int mptcp_init_sock(struct sock *sk)
2701{
2702 struct net *net = sock_net(sk);
2703 int ret;
2704
2705 ret = __mptcp_init_sock(sk);
2706 if (ret)
2707 return ret;
2708
2709 if (!mptcp_is_enabled(net))
2710 return -ENOPROTOOPT;
2711
2712 if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net))
2713 return -ENOMEM;
2714
2715 ret = __mptcp_socket_create(mptcp_sk(sk));
2716 if (ret)
2717 return ret;
2718
2719 set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags);
2720
2721 /* fetch the ca name; do it outside __mptcp_init_sock(), so that clone will
2722 * propagate the correct value
2723 */
2724 mptcp_ca_reset(sk);
2725
2726 sk_sockets_allocated_inc(sk);
2727 sk->sk_rcvbuf = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[1]);
2728 sk->sk_sndbuf = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[1]);
2729
2730 return 0;
2731}
2732
2733static void __mptcp_clear_xmit(struct sock *sk)
2734{
2735 struct mptcp_sock *msk = mptcp_sk(sk);
2736 struct mptcp_data_frag *dtmp, *dfrag;
2737
2738 WRITE_ONCE(msk->first_pending, NULL);
2739 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list)
2740 dfrag_clear(sk, dfrag);
2741}
2742
2743void mptcp_cancel_work(struct sock *sk)
2744{
2745 struct mptcp_sock *msk = mptcp_sk(sk);
2746
2747 if (cancel_work_sync(&msk->work))
2748 __sock_put(sk);
2749}
2750
2751void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how)
2752{
2753 lock_sock(ssk);
2754
2755 switch (ssk->sk_state) {
2756 case TCP_LISTEN:
2757 if (!(how & RCV_SHUTDOWN))
2758 break;
2759 fallthrough;
2760 case TCP_SYN_SENT:
2761 tcp_disconnect(ssk, O_NONBLOCK);
2762 break;
2763 default:
2764 if (__mptcp_check_fallback(mptcp_sk(sk))) {
2765 pr_debug("Fallback");
2766 ssk->sk_shutdown |= how;
2767 tcp_shutdown(ssk, how);
2768 } else {
2769 pr_debug("Sending DATA_FIN on subflow %p", ssk);
2770 tcp_send_ack(ssk);
2771 if (!mptcp_timer_pending(sk))
2772 mptcp_reset_timer(sk);
2773 }
2774 break;
2775 }
2776
2777 release_sock(ssk);
2778}
2779
2780static const unsigned char new_state[16] = {
2781 /* current state: new state: action: */
2782 [0 /* (Invalid) */] = TCP_CLOSE,
2783 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2784 [TCP_SYN_SENT] = TCP_CLOSE,
2785 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2786 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1,
2787 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2,
2788 [TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */
2789 [TCP_CLOSE] = TCP_CLOSE,
2790 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN,
2791 [TCP_LAST_ACK] = TCP_LAST_ACK,
2792 [TCP_LISTEN] = TCP_CLOSE,
2793 [TCP_CLOSING] = TCP_CLOSING,
2794 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */
2795};
2796
2797static int mptcp_close_state(struct sock *sk)
2798{
2799 int next = (int)new_state[sk->sk_state];
2800 int ns = next & TCP_STATE_MASK;
2801
2802 inet_sk_state_store(sk, ns);
2803
2804 return next & TCP_ACTION_FIN;
2805}
2806
2807static void __mptcp_check_send_data_fin(struct sock *sk)
2808{
2809 struct mptcp_subflow_context *subflow;
2810 struct mptcp_sock *msk = mptcp_sk(sk);
2811
2812 pr_debug("msk=%p snd_data_fin_enable=%d pending=%d snd_nxt=%llu write_seq=%llu",
2813 msk, msk->snd_data_fin_enable, !!mptcp_send_head(sk),
2814 msk->snd_nxt, msk->write_seq);
2815
2816 /* we still need to enqueue subflows or not really shutting down,
2817 * skip this
2818 */
2819 if (!msk->snd_data_fin_enable || msk->snd_nxt + 1 != msk->write_seq ||
2820 mptcp_send_head(sk))
2821 return;
2822
2823 WRITE_ONCE(msk->snd_nxt, msk->write_seq);
2824
2825 /* fallback socket will not get data_fin/ack, can move to the next
2826 * state now
2827 */
2828 if (__mptcp_check_fallback(msk)) {
2829 WRITE_ONCE(msk->snd_una, msk->write_seq);
2830 if ((1 << sk->sk_state) & (TCPF_CLOSING | TCPF_LAST_ACK)) {
2831 inet_sk_state_store(sk, TCP_CLOSE);
2832 mptcp_close_wake_up(sk);
2833 } else if (sk->sk_state == TCP_FIN_WAIT1) {
2834 inet_sk_state_store(sk, TCP_FIN_WAIT2);
2835 }
2836 }
2837
2838 mptcp_for_each_subflow(msk, subflow) {
2839 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
2840
2841 mptcp_subflow_shutdown(sk, tcp_sk, SEND_SHUTDOWN);
2842 }
2843}
2844
2845static void __mptcp_wr_shutdown(struct sock *sk)
2846{
2847 struct mptcp_sock *msk = mptcp_sk(sk);
2848
2849 pr_debug("msk=%p snd_data_fin_enable=%d shutdown=%x state=%d pending=%d",
2850 msk, msk->snd_data_fin_enable, sk->sk_shutdown, sk->sk_state,
2851 !!mptcp_send_head(sk));
2852
2853 /* will be ignored by fallback sockets */
2854 WRITE_ONCE(msk->write_seq, msk->write_seq + 1);
2855 WRITE_ONCE(msk->snd_data_fin_enable, 1);
2856
2857 __mptcp_check_send_data_fin(sk);
2858}
2859
2860static void __mptcp_destroy_sock(struct sock *sk)
2861{
2862 struct mptcp_sock *msk = mptcp_sk(sk);
2863
2864 pr_debug("msk=%p", msk);
2865
2866 might_sleep();
2867
2868 mptcp_stop_timer(sk);
2869 sk_stop_timer(sk, &sk->sk_timer);
2870 msk->pm.status = 0;
2871
2872 sk->sk_prot->destroy(sk);
2873
2874 WARN_ON_ONCE(msk->rmem_fwd_alloc);
2875 WARN_ON_ONCE(msk->rmem_released);
2876 sk_stream_kill_queues(sk);
2877 xfrm_sk_free_policy(sk);
2878
2879 sk_refcnt_debug_release(sk);
2880 sock_put(sk);
2881}
2882
2883static __poll_t mptcp_check_readable(struct mptcp_sock *msk)
2884{
2885 /* Concurrent splices from sk_receive_queue into receive_queue will
2886 * always show at least one non-empty queue when checked in this order.
2887 */
2888 if (skb_queue_empty_lockless(&((struct sock *)msk)->sk_receive_queue) &&
2889 skb_queue_empty_lockless(&msk->receive_queue))
2890 return 0;
2891
2892 return EPOLLIN | EPOLLRDNORM;
2893}
2894
2895bool __mptcp_close(struct sock *sk, long timeout)
2896{
2897 struct mptcp_subflow_context *subflow;
2898 struct mptcp_sock *msk = mptcp_sk(sk);
2899 bool do_cancel_work = false;
2900 int subflows_alive = 0;
2901
2902 sk->sk_shutdown = SHUTDOWN_MASK;
2903
2904 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) {
2905 inet_sk_state_store(sk, TCP_CLOSE);
2906 goto cleanup;
2907 }
2908
2909 if (mptcp_check_readable(msk)) {
2910 /* the msk has read data, do the MPTCP equivalent of TCP reset */
2911 inet_sk_state_store(sk, TCP_CLOSE);
2912 mptcp_do_fastclose(sk);
2913 } else if (mptcp_close_state(sk)) {
2914 __mptcp_wr_shutdown(sk);
2915 }
2916
2917 sk_stream_wait_close(sk, timeout);
2918
2919cleanup:
2920 /* orphan all the subflows */
2921 inet_csk(sk)->icsk_mtup.probe_timestamp = tcp_jiffies32;
2922 mptcp_for_each_subflow(msk, subflow) {
2923 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2924 bool slow = lock_sock_fast_nested(ssk);
2925
2926 subflows_alive += ssk->sk_state != TCP_CLOSE;
2927
2928 /* since the close timeout takes precedence on the fail one,
2929 * cancel the latter
2930 */
2931 if (ssk == msk->first)
2932 subflow->fail_tout = 0;
2933
2934 /* detach from the parent socket, but allow data_ready to
2935 * push incoming data into the mptcp stack, to properly ack it
2936 */
2937 ssk->sk_socket = NULL;
2938 ssk->sk_wq = NULL;
2939 unlock_sock_fast(ssk, slow);
2940 }
2941 sock_orphan(sk);
2942
2943 /* all the subflows are closed, only timeout can change the msk
2944 * state, let's not keep resources busy for no reasons
2945 */
2946 if (subflows_alive == 0)
2947 inet_sk_state_store(sk, TCP_CLOSE);
2948
2949 sock_hold(sk);
2950 pr_debug("msk=%p state=%d", sk, sk->sk_state);
2951 if (msk->token)
2952 mptcp_event(MPTCP_EVENT_CLOSED, msk, NULL, GFP_KERNEL);
2953
2954 if (sk->sk_state == TCP_CLOSE) {
2955 __mptcp_destroy_sock(sk);
2956 do_cancel_work = true;
2957 } else {
2958 mptcp_reset_timeout(msk, 0);
2959 }
2960
2961 return do_cancel_work;
2962}
2963
2964static void mptcp_close(struct sock *sk, long timeout)
2965{
2966 bool do_cancel_work;
2967
2968 lock_sock(sk);
2969
2970 do_cancel_work = __mptcp_close(sk, timeout);
2971 release_sock(sk);
2972 if (do_cancel_work)
2973 mptcp_cancel_work(sk);
2974
2975 sock_put(sk);
2976}
2977
2978void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk)
2979{
2980#if IS_ENABLED(CONFIG_MPTCP_IPV6)
2981 const struct ipv6_pinfo *ssk6 = inet6_sk(ssk);
2982 struct ipv6_pinfo *msk6 = inet6_sk(msk);
2983
2984 msk->sk_v6_daddr = ssk->sk_v6_daddr;
2985 msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr;
2986
2987 if (msk6 && ssk6) {
2988 msk6->saddr = ssk6->saddr;
2989 msk6->flow_label = ssk6->flow_label;
2990 }
2991#endif
2992
2993 inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num;
2994 inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport;
2995 inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport;
2996 inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr;
2997 inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr;
2998 inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr;
2999}
3000
3001static int mptcp_disconnect(struct sock *sk, int flags)
3002{
3003 struct mptcp_sock *msk = mptcp_sk(sk);
3004
3005 /* We are on the fastopen error path. We can't call straight into the
3006 * subflows cleanup code due to lock nesting (we are already under
3007 * msk->firstsocket lock). Do nothing and leave the cleanup to the
3008 * caller.
3009 */
3010 if (msk->fastopening)
3011 return 0;
3012
3013 inet_sk_state_store(sk, TCP_CLOSE);
3014
3015 mptcp_stop_timer(sk);
3016 sk_stop_timer(sk, &sk->sk_timer);
3017
3018 if (msk->token)
3019 mptcp_event(MPTCP_EVENT_CLOSED, msk, NULL, GFP_KERNEL);
3020
3021 /* msk->subflow is still intact, the following will not free the first
3022 * subflow
3023 */
3024 mptcp_destroy_common(msk, MPTCP_CF_FASTCLOSE);
3025 msk->last_snd = NULL;
3026 WRITE_ONCE(msk->flags, 0);
3027 msk->cb_flags = 0;
3028 msk->push_pending = 0;
3029 msk->recovery = false;
3030 msk->can_ack = false;
3031 msk->fully_established = false;
3032 msk->rcv_data_fin = false;
3033 msk->snd_data_fin_enable = false;
3034 msk->rcv_fastclose = false;
3035 msk->use_64bit_ack = false;
3036 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
3037 mptcp_pm_data_reset(msk);
3038 mptcp_ca_reset(sk);
3039
3040 sk->sk_shutdown = 0;
3041 sk_error_report(sk);
3042 return 0;
3043}
3044
3045#if IS_ENABLED(CONFIG_MPTCP_IPV6)
3046static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk)
3047{
3048 unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo);
3049
3050 return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
3051}
3052#endif
3053
3054struct sock *mptcp_sk_clone(const struct sock *sk,
3055 const struct mptcp_options_received *mp_opt,
3056 struct request_sock *req)
3057{
3058 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
3059 struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC);
3060 struct mptcp_sock *msk;
3061
3062 if (!nsk)
3063 return NULL;
3064
3065#if IS_ENABLED(CONFIG_MPTCP_IPV6)
3066 if (nsk->sk_family == AF_INET6)
3067 inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk);
3068#endif
3069
3070 __mptcp_init_sock(nsk);
3071
3072 msk = mptcp_sk(nsk);
3073 msk->local_key = subflow_req->local_key;
3074 msk->token = subflow_req->token;
3075 msk->subflow = NULL;
3076 WRITE_ONCE(msk->fully_established, false);
3077 if (mp_opt->suboptions & OPTION_MPTCP_CSUMREQD)
3078 WRITE_ONCE(msk->csum_enabled, true);
3079
3080 msk->write_seq = subflow_req->idsn + 1;
3081 msk->snd_nxt = msk->write_seq;
3082 msk->snd_una = msk->write_seq;
3083 msk->wnd_end = msk->snd_nxt + req->rsk_rcv_wnd;
3084 msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq;
3085
3086 sock_reset_flag(nsk, SOCK_RCU_FREE);
3087 /* will be fully established after successful MPC subflow creation */
3088 inet_sk_state_store(nsk, TCP_SYN_RECV);
3089
3090 security_inet_csk_clone(nsk, req);
3091 bh_unlock_sock(nsk);
3092
3093 /* keep a single reference */
3094 __sock_put(nsk);
3095 return nsk;
3096}
3097
3098void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk)
3099{
3100 const struct tcp_sock *tp = tcp_sk(ssk);
3101
3102 msk->rcvq_space.copied = 0;
3103 msk->rcvq_space.rtt_us = 0;
3104
3105 msk->rcvq_space.time = tp->tcp_mstamp;
3106
3107 /* initial rcv_space offering made to peer */
3108 msk->rcvq_space.space = min_t(u32, tp->rcv_wnd,
3109 TCP_INIT_CWND * tp->advmss);
3110 if (msk->rcvq_space.space == 0)
3111 msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT;
3112
3113 WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd);
3114}
3115
3116static struct sock *mptcp_accept(struct sock *sk, int flags, int *err,
3117 bool kern)
3118{
3119 struct mptcp_sock *msk = mptcp_sk(sk);
3120 struct socket *listener;
3121 struct sock *newsk;
3122
3123 listener = __mptcp_nmpc_socket(msk);
3124 if (WARN_ON_ONCE(!listener)) {
3125 *err = -EINVAL;
3126 return NULL;
3127 }
3128
3129 pr_debug("msk=%p, listener=%p", msk, mptcp_subflow_ctx(listener->sk));
3130 newsk = inet_csk_accept(listener->sk, flags, err, kern);
3131 if (!newsk)
3132 return NULL;
3133
3134 pr_debug("msk=%p, subflow is mptcp=%d", msk, sk_is_mptcp(newsk));
3135 if (sk_is_mptcp(newsk)) {
3136 struct mptcp_subflow_context *subflow;
3137 struct sock *new_mptcp_sock;
3138
3139 subflow = mptcp_subflow_ctx(newsk);
3140 new_mptcp_sock = subflow->conn;
3141
3142 /* is_mptcp should be false if subflow->conn is missing, see
3143 * subflow_syn_recv_sock()
3144 */
3145 if (WARN_ON_ONCE(!new_mptcp_sock)) {
3146 tcp_sk(newsk)->is_mptcp = 0;
3147 goto out;
3148 }
3149
3150 /* acquire the 2nd reference for the owning socket */
3151 sock_hold(new_mptcp_sock);
3152 newsk = new_mptcp_sock;
3153 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEPASSIVEACK);
3154 } else {
3155 MPTCP_INC_STATS(sock_net(sk),
3156 MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK);
3157 }
3158
3159out:
3160 newsk->sk_kern_sock = kern;
3161 return newsk;
3162}
3163
3164void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags)
3165{
3166 struct mptcp_subflow_context *subflow, *tmp;
3167 struct sock *sk = (struct sock *)msk;
3168
3169 __mptcp_clear_xmit(sk);
3170
3171 /* join list will be eventually flushed (with rst) at sock lock release time */
3172 mptcp_for_each_subflow_safe(msk, subflow, tmp)
3173 __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), subflow, flags);
3174
3175 /* move to sk_receive_queue, sk_stream_kill_queues will purge it */
3176 mptcp_data_lock(sk);
3177 skb_queue_splice_tail_init(&msk->receive_queue, &sk->sk_receive_queue);
3178 __skb_queue_purge(&sk->sk_receive_queue);
3179 skb_rbtree_purge(&msk->out_of_order_queue);
3180 mptcp_data_unlock(sk);
3181
3182 /* move all the rx fwd alloc into the sk_mem_reclaim_final in
3183 * inet_sock_destruct() will dispose it
3184 */
3185 sk->sk_forward_alloc += msk->rmem_fwd_alloc;
3186 msk->rmem_fwd_alloc = 0;
3187 mptcp_token_destroy(msk);
3188 mptcp_pm_free_anno_list(msk);
3189 mptcp_free_local_addr_list(msk);
3190}
3191
3192static void mptcp_destroy(struct sock *sk)
3193{
3194 struct mptcp_sock *msk = mptcp_sk(sk);
3195
3196 /* clears msk->subflow, allowing the following to close
3197 * even the initial subflow
3198 */
3199 mptcp_dispose_initial_subflow(msk);
3200 mptcp_destroy_common(msk, 0);
3201 sk_sockets_allocated_dec(sk);
3202}
3203
3204void __mptcp_data_acked(struct sock *sk)
3205{
3206 if (!sock_owned_by_user(sk))
3207 __mptcp_clean_una(sk);
3208 else
3209 __set_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->cb_flags);
3210
3211 if (mptcp_pending_data_fin_ack(sk))
3212 mptcp_schedule_work(sk);
3213}
3214
3215void __mptcp_check_push(struct sock *sk, struct sock *ssk)
3216{
3217 if (!mptcp_send_head(sk))
3218 return;
3219
3220 if (!sock_owned_by_user(sk))
3221 __mptcp_subflow_push_pending(sk, ssk, false);
3222 else
3223 __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags);
3224}
3225
3226#define MPTCP_FLAGS_PROCESS_CTX_NEED (BIT(MPTCP_PUSH_PENDING) | \
3227 BIT(MPTCP_RETRANSMIT) | \
3228 BIT(MPTCP_FLUSH_JOIN_LIST))
3229
3230/* processes deferred events and flush wmem */
3231static void mptcp_release_cb(struct sock *sk)
3232 __must_hold(&sk->sk_lock.slock)
3233{
3234 struct mptcp_sock *msk = mptcp_sk(sk);
3235
3236 for (;;) {
3237 unsigned long flags = (msk->cb_flags & MPTCP_FLAGS_PROCESS_CTX_NEED) |
3238 msk->push_pending;
3239 if (!flags)
3240 break;
3241
3242 /* the following actions acquire the subflow socket lock
3243 *
3244 * 1) can't be invoked in atomic scope
3245 * 2) must avoid ABBA deadlock with msk socket spinlock: the RX
3246 * datapath acquires the msk socket spinlock while helding
3247 * the subflow socket lock
3248 */
3249 msk->push_pending = 0;
3250 msk->cb_flags &= ~flags;
3251 spin_unlock_bh(&sk->sk_lock.slock);
3252 if (flags & BIT(MPTCP_FLUSH_JOIN_LIST))
3253 __mptcp_flush_join_list(sk);
3254 if (flags & BIT(MPTCP_PUSH_PENDING))
3255 __mptcp_push_pending(sk, 0);
3256 if (flags & BIT(MPTCP_RETRANSMIT))
3257 __mptcp_retrans(sk);
3258
3259 cond_resched();
3260 spin_lock_bh(&sk->sk_lock.slock);
3261 }
3262
3263 if (__test_and_clear_bit(MPTCP_CLEAN_UNA, &msk->cb_flags))
3264 __mptcp_clean_una_wakeup(sk);
3265 if (unlikely(&msk->cb_flags)) {
3266 /* be sure to set the current sk state before tacking actions
3267 * depending on sk_state, that is processing MPTCP_ERROR_REPORT
3268 */
3269 if (__test_and_clear_bit(MPTCP_CONNECTED, &msk->cb_flags))
3270 __mptcp_set_connected(sk);
3271 if (__test_and_clear_bit(MPTCP_ERROR_REPORT, &msk->cb_flags))
3272 __mptcp_error_report(sk);
3273 if (__test_and_clear_bit(MPTCP_RESET_SCHEDULER, &msk->cb_flags))
3274 msk->last_snd = NULL;
3275 }
3276
3277 __mptcp_update_rmem(sk);
3278}
3279
3280/* MP_JOIN client subflow must wait for 4th ack before sending any data:
3281 * TCP can't schedule delack timer before the subflow is fully established.
3282 * MPTCP uses the delack timer to do 3rd ack retransmissions
3283 */
3284static void schedule_3rdack_retransmission(struct sock *ssk)
3285{
3286 struct inet_connection_sock *icsk = inet_csk(ssk);
3287 struct tcp_sock *tp = tcp_sk(ssk);
3288 unsigned long timeout;
3289
3290 if (mptcp_subflow_ctx(ssk)->fully_established)
3291 return;
3292
3293 /* reschedule with a timeout above RTT, as we must look only for drop */
3294 if (tp->srtt_us)
3295 timeout = usecs_to_jiffies(tp->srtt_us >> (3 - 1));
3296 else
3297 timeout = TCP_TIMEOUT_INIT;
3298 timeout += jiffies;
3299
3300 WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER);
3301 icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
3302 icsk->icsk_ack.timeout = timeout;
3303 sk_reset_timer(ssk, &icsk->icsk_delack_timer, timeout);
3304}
3305
3306void mptcp_subflow_process_delegated(struct sock *ssk)
3307{
3308 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
3309 struct sock *sk = subflow->conn;
3310
3311 if (test_bit(MPTCP_DELEGATE_SEND, &subflow->delegated_status)) {
3312 mptcp_data_lock(sk);
3313 if (!sock_owned_by_user(sk))
3314 __mptcp_subflow_push_pending(sk, ssk, true);
3315 else
3316 __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags);
3317 mptcp_data_unlock(sk);
3318 mptcp_subflow_delegated_done(subflow, MPTCP_DELEGATE_SEND);
3319 }
3320 if (test_bit(MPTCP_DELEGATE_ACK, &subflow->delegated_status)) {
3321 schedule_3rdack_retransmission(ssk);
3322 mptcp_subflow_delegated_done(subflow, MPTCP_DELEGATE_ACK);
3323 }
3324}
3325
3326static int mptcp_hash(struct sock *sk)
3327{
3328 /* should never be called,
3329 * we hash the TCP subflows not the master socket
3330 */
3331 WARN_ON_ONCE(1);
3332 return 0;
3333}
3334
3335static void mptcp_unhash(struct sock *sk)
3336{
3337 /* called from sk_common_release(), but nothing to do here */
3338}
3339
3340static int mptcp_get_port(struct sock *sk, unsigned short snum)
3341{
3342 struct mptcp_sock *msk = mptcp_sk(sk);
3343 struct socket *ssock;
3344
3345 ssock = __mptcp_nmpc_socket(msk);
3346 pr_debug("msk=%p, subflow=%p", msk, ssock);
3347 if (WARN_ON_ONCE(!ssock))
3348 return -EINVAL;
3349
3350 return inet_csk_get_port(ssock->sk, snum);
3351}
3352
3353void mptcp_finish_connect(struct sock *ssk)
3354{
3355 struct mptcp_subflow_context *subflow;
3356 struct mptcp_sock *msk;
3357 struct sock *sk;
3358
3359 subflow = mptcp_subflow_ctx(ssk);
3360 sk = subflow->conn;
3361 msk = mptcp_sk(sk);
3362
3363 pr_debug("msk=%p, token=%u", sk, subflow->token);
3364
3365 subflow->map_seq = subflow->iasn;
3366 subflow->map_subflow_seq = 1;
3367
3368 /* the socket is not connected yet, no msk/subflow ops can access/race
3369 * accessing the field below
3370 */
3371 WRITE_ONCE(msk->local_key, subflow->local_key);
3372 WRITE_ONCE(msk->write_seq, subflow->idsn + 1);
3373 WRITE_ONCE(msk->snd_nxt, msk->write_seq);
3374 WRITE_ONCE(msk->snd_una, msk->write_seq);
3375
3376 mptcp_pm_new_connection(msk, ssk, 0);
3377
3378 mptcp_rcv_space_init(msk, ssk);
3379}
3380
3381void mptcp_sock_graft(struct sock *sk, struct socket *parent)
3382{
3383 write_lock_bh(&sk->sk_callback_lock);
3384 rcu_assign_pointer(sk->sk_wq, &parent->wq);
3385 sk_set_socket(sk, parent);
3386 sk->sk_uid = SOCK_INODE(parent)->i_uid;
3387 write_unlock_bh(&sk->sk_callback_lock);
3388}
3389
3390bool mptcp_finish_join(struct sock *ssk)
3391{
3392 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
3393 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
3394 struct sock *parent = (void *)msk;
3395 bool ret = true;
3396
3397 pr_debug("msk=%p, subflow=%p", msk, subflow);
3398
3399 /* mptcp socket already closing? */
3400 if (!mptcp_is_fully_established(parent)) {
3401 subflow->reset_reason = MPTCP_RST_EMPTCP;
3402 return false;
3403 }
3404
3405 if (!list_empty(&subflow->node))
3406 goto out;
3407
3408 if (!mptcp_pm_allow_new_subflow(msk))
3409 goto err_prohibited;
3410
3411 /* active connections are already on conn_list.
3412 * If we can't acquire msk socket lock here, let the release callback
3413 * handle it
3414 */
3415 mptcp_data_lock(parent);
3416 if (!sock_owned_by_user(parent)) {
3417 ret = __mptcp_finish_join(msk, ssk);
3418 if (ret) {
3419 sock_hold(ssk);
3420 list_add_tail(&subflow->node, &msk->conn_list);
3421 }
3422 } else {
3423 sock_hold(ssk);
3424 list_add_tail(&subflow->node, &msk->join_list);
3425 __set_bit(MPTCP_FLUSH_JOIN_LIST, &msk->cb_flags);
3426 }
3427 mptcp_data_unlock(parent);
3428
3429 if (!ret) {
3430err_prohibited:
3431 subflow->reset_reason = MPTCP_RST_EPROHIBIT;
3432 return false;
3433 }
3434
3435 subflow->map_seq = READ_ONCE(msk->ack_seq);
3436 WRITE_ONCE(msk->allow_infinite_fallback, false);
3437
3438out:
3439 mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC);
3440 return true;
3441}
3442
3443static void mptcp_shutdown(struct sock *sk, int how)
3444{
3445 pr_debug("sk=%p, how=%d", sk, how);
3446
3447 if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk))
3448 __mptcp_wr_shutdown(sk);
3449}
3450
3451static int mptcp_forward_alloc_get(const struct sock *sk)
3452{
3453 return sk->sk_forward_alloc + mptcp_sk(sk)->rmem_fwd_alloc;
3454}
3455
3456static int mptcp_ioctl_outq(const struct mptcp_sock *msk, u64 v)
3457{
3458 const struct sock *sk = (void *)msk;
3459 u64 delta;
3460
3461 if (sk->sk_state == TCP_LISTEN)
3462 return -EINVAL;
3463
3464 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
3465 return 0;
3466
3467 delta = msk->write_seq - v;
3468 if (__mptcp_check_fallback(msk) && msk->first) {
3469 struct tcp_sock *tp = tcp_sk(msk->first);
3470
3471 /* the first subflow is disconnected after close - see
3472 * __mptcp_close_ssk(). tcp_disconnect() moves the write_seq
3473 * so ignore that status, too.
3474 */
3475 if (!((1 << msk->first->sk_state) &
3476 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE)))
3477 delta += READ_ONCE(tp->write_seq) - tp->snd_una;
3478 }
3479 if (delta > INT_MAX)
3480 delta = INT_MAX;
3481
3482 return (int)delta;
3483}
3484
3485static int mptcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
3486{
3487 struct mptcp_sock *msk = mptcp_sk(sk);
3488 bool slow;
3489 int answ;
3490
3491 switch (cmd) {
3492 case SIOCINQ:
3493 if (sk->sk_state == TCP_LISTEN)
3494 return -EINVAL;
3495
3496 lock_sock(sk);
3497 __mptcp_move_skbs(msk);
3498 answ = mptcp_inq_hint(sk);
3499 release_sock(sk);
3500 break;
3501 case SIOCOUTQ:
3502 slow = lock_sock_fast(sk);
3503 answ = mptcp_ioctl_outq(msk, READ_ONCE(msk->snd_una));
3504 unlock_sock_fast(sk, slow);
3505 break;
3506 case SIOCOUTQNSD:
3507 slow = lock_sock_fast(sk);
3508 answ = mptcp_ioctl_outq(msk, msk->snd_nxt);
3509 unlock_sock_fast(sk, slow);
3510 break;
3511 default:
3512 return -ENOIOCTLCMD;
3513 }
3514
3515 return put_user(answ, (int __user *)arg);
3516}
3517
3518static void mptcp_subflow_early_fallback(struct mptcp_sock *msk,
3519 struct mptcp_subflow_context *subflow)
3520{
3521 subflow->request_mptcp = 0;
3522 __mptcp_do_fallback(msk);
3523}
3524
3525static int mptcp_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
3526{
3527 struct mptcp_subflow_context *subflow;
3528 struct mptcp_sock *msk = mptcp_sk(sk);
3529 struct socket *ssock;
3530 int err = -EINVAL;
3531
3532 ssock = __mptcp_nmpc_socket(msk);
3533 if (!ssock)
3534 return -EINVAL;
3535
3536 mptcp_token_destroy(msk);
3537 inet_sk_state_store(sk, TCP_SYN_SENT);
3538 subflow = mptcp_subflow_ctx(ssock->sk);
3539#ifdef CONFIG_TCP_MD5SIG
3540 /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
3541 * TCP option space.
3542 */
3543 if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info))
3544 mptcp_subflow_early_fallback(msk, subflow);
3545#endif
3546 if (subflow->request_mptcp && mptcp_token_new_connect(ssock->sk)) {
3547 MPTCP_INC_STATS(sock_net(ssock->sk), MPTCP_MIB_TOKENFALLBACKINIT);
3548 mptcp_subflow_early_fallback(msk, subflow);
3549 }
3550 if (likely(!__mptcp_check_fallback(msk)))
3551 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVE);
3552
3553 /* if reaching here via the fastopen/sendmsg path, the caller already
3554 * acquired the subflow socket lock, too.
3555 */
3556 if (msk->fastopening)
3557 err = __inet_stream_connect(ssock, uaddr, addr_len, msk->connect_flags, 1);
3558 else
3559 err = inet_stream_connect(ssock, uaddr, addr_len, msk->connect_flags);
3560 inet_sk(sk)->defer_connect = inet_sk(ssock->sk)->defer_connect;
3561
3562 /* on successful connect, the msk state will be moved to established by
3563 * subflow_finish_connect()
3564 */
3565 if (unlikely(err && err != -EINPROGRESS)) {
3566 inet_sk_state_store(sk, inet_sk_state_load(ssock->sk));
3567 return err;
3568 }
3569
3570 mptcp_copy_inaddrs(sk, ssock->sk);
3571
3572 /* unblocking connect, mptcp-level inet_stream_connect will error out
3573 * without changing the socket state, update it here.
3574 */
3575 if (err == -EINPROGRESS)
3576 sk->sk_socket->state = ssock->state;
3577 return err;
3578}
3579
3580static struct proto mptcp_prot = {
3581 .name = "MPTCP",
3582 .owner = THIS_MODULE,
3583 .init = mptcp_init_sock,
3584 .connect = mptcp_connect,
3585 .disconnect = mptcp_disconnect,
3586 .close = mptcp_close,
3587 .accept = mptcp_accept,
3588 .setsockopt = mptcp_setsockopt,
3589 .getsockopt = mptcp_getsockopt,
3590 .shutdown = mptcp_shutdown,
3591 .destroy = mptcp_destroy,
3592 .sendmsg = mptcp_sendmsg,
3593 .ioctl = mptcp_ioctl,
3594 .recvmsg = mptcp_recvmsg,
3595 .release_cb = mptcp_release_cb,
3596 .hash = mptcp_hash,
3597 .unhash = mptcp_unhash,
3598 .get_port = mptcp_get_port,
3599 .forward_alloc_get = mptcp_forward_alloc_get,
3600 .sockets_allocated = &mptcp_sockets_allocated,
3601
3602 .memory_allocated = &tcp_memory_allocated,
3603 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc,
3604
3605 .memory_pressure = &tcp_memory_pressure,
3606 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
3607 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
3608 .sysctl_mem = sysctl_tcp_mem,
3609 .obj_size = sizeof(struct mptcp_sock),
3610 .slab_flags = SLAB_TYPESAFE_BY_RCU,
3611 .no_autobind = true,
3612};
3613
3614static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
3615{
3616 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3617 struct socket *ssock;
3618 int err;
3619
3620 lock_sock(sock->sk);
3621 ssock = __mptcp_nmpc_socket(msk);
3622 if (!ssock) {
3623 err = -EINVAL;
3624 goto unlock;
3625 }
3626
3627 err = ssock->ops->bind(ssock, uaddr, addr_len);
3628 if (!err)
3629 mptcp_copy_inaddrs(sock->sk, ssock->sk);
3630
3631unlock:
3632 release_sock(sock->sk);
3633 return err;
3634}
3635
3636static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
3637 int addr_len, int flags)
3638{
3639 int ret;
3640
3641 lock_sock(sock->sk);
3642 mptcp_sk(sock->sk)->connect_flags = flags;
3643 ret = __inet_stream_connect(sock, uaddr, addr_len, flags, 0);
3644 release_sock(sock->sk);
3645 return ret;
3646}
3647
3648static int mptcp_listen(struct socket *sock, int backlog)
3649{
3650 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3651 struct socket *ssock;
3652 int err;
3653
3654 pr_debug("msk=%p", msk);
3655
3656 lock_sock(sock->sk);
3657 ssock = __mptcp_nmpc_socket(msk);
3658 if (!ssock) {
3659 err = -EINVAL;
3660 goto unlock;
3661 }
3662
3663 mptcp_token_destroy(msk);
3664 inet_sk_state_store(sock->sk, TCP_LISTEN);
3665 sock_set_flag(sock->sk, SOCK_RCU_FREE);
3666
3667 err = ssock->ops->listen(ssock, backlog);
3668 inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
3669 if (!err)
3670 mptcp_copy_inaddrs(sock->sk, ssock->sk);
3671
3672 mptcp_event_pm_listener(ssock->sk, MPTCP_EVENT_LISTENER_CREATED);
3673
3674unlock:
3675 release_sock(sock->sk);
3676 return err;
3677}
3678
3679static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
3680 int flags, bool kern)
3681{
3682 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3683 struct socket *ssock;
3684 int err;
3685
3686 pr_debug("msk=%p", msk);
3687
3688 ssock = __mptcp_nmpc_socket(msk);
3689 if (!ssock)
3690 return -EINVAL;
3691
3692 err = ssock->ops->accept(sock, newsock, flags, kern);
3693 if (err == 0 && !mptcp_is_tcpsk(newsock->sk)) {
3694 struct mptcp_sock *msk = mptcp_sk(newsock->sk);
3695 struct mptcp_subflow_context *subflow;
3696 struct sock *newsk = newsock->sk;
3697
3698 set_bit(SOCK_CUSTOM_SOCKOPT, &newsock->flags);
3699
3700 lock_sock(newsk);
3701
3702 /* PM/worker can now acquire the first subflow socket
3703 * lock without racing with listener queue cleanup,
3704 * we can notify it, if needed.
3705 *
3706 * Even if remote has reset the initial subflow by now
3707 * the refcnt is still at least one.
3708 */
3709 subflow = mptcp_subflow_ctx(msk->first);
3710 list_add(&subflow->node, &msk->conn_list);
3711 sock_hold(msk->first);
3712 if (mptcp_is_fully_established(newsk))
3713 mptcp_pm_fully_established(msk, msk->first, GFP_KERNEL);
3714
3715 mptcp_rcv_space_init(msk, msk->first);
3716 mptcp_propagate_sndbuf(newsk, msk->first);
3717
3718 /* set ssk->sk_socket of accept()ed flows to mptcp socket.
3719 * This is needed so NOSPACE flag can be set from tcp stack.
3720 */
3721 mptcp_for_each_subflow(msk, subflow) {
3722 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3723
3724 if (!ssk->sk_socket)
3725 mptcp_sock_graft(ssk, newsock);
3726 }
3727 release_sock(newsk);
3728 }
3729
3730 return err;
3731}
3732
3733static __poll_t mptcp_check_writeable(struct mptcp_sock *msk)
3734{
3735 struct sock *sk = (struct sock *)msk;
3736
3737 if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
3738 return EPOLLOUT | EPOLLWRNORM;
3739
3740 if (sk_stream_is_writeable(sk))
3741 return EPOLLOUT | EPOLLWRNORM;
3742
3743 mptcp_set_nospace(sk);
3744 smp_mb__after_atomic(); /* msk->flags is changed by write_space cb */
3745 if (sk_stream_is_writeable(sk))
3746 return EPOLLOUT | EPOLLWRNORM;
3747
3748 return 0;
3749}
3750
3751static __poll_t mptcp_poll(struct file *file, struct socket *sock,
3752 struct poll_table_struct *wait)
3753{
3754 struct sock *sk = sock->sk;
3755 struct mptcp_sock *msk;
3756 __poll_t mask = 0;
3757 int state;
3758
3759 msk = mptcp_sk(sk);
3760 sock_poll_wait(file, sock, wait);
3761
3762 state = inet_sk_state_load(sk);
3763 pr_debug("msk=%p state=%d flags=%lx", msk, state, msk->flags);
3764 if (state == TCP_LISTEN) {
3765 if (WARN_ON_ONCE(!msk->subflow || !msk->subflow->sk))
3766 return 0;
3767
3768 return inet_csk_listen_poll(msk->subflow->sk);
3769 }
3770
3771 if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) {
3772 mask |= mptcp_check_readable(msk);
3773 mask |= mptcp_check_writeable(msk);
3774 } else if (state == TCP_SYN_SENT && inet_sk(sk)->defer_connect) {
3775 /* cf tcp_poll() note about TFO */
3776 mask |= EPOLLOUT | EPOLLWRNORM;
3777 }
3778 if (sk->sk_shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
3779 mask |= EPOLLHUP;
3780 if (sk->sk_shutdown & RCV_SHUTDOWN)
3781 mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
3782
3783 /* This barrier is coupled with smp_wmb() in __mptcp_error_report() */
3784 smp_rmb();
3785 if (sk->sk_err)
3786 mask |= EPOLLERR;
3787
3788 return mask;
3789}
3790
3791static const struct proto_ops mptcp_stream_ops = {
3792 .family = PF_INET,
3793 .owner = THIS_MODULE,
3794 .release = inet_release,
3795 .bind = mptcp_bind,
3796 .connect = mptcp_stream_connect,
3797 .socketpair = sock_no_socketpair,
3798 .accept = mptcp_stream_accept,
3799 .getname = inet_getname,
3800 .poll = mptcp_poll,
3801 .ioctl = inet_ioctl,
3802 .gettstamp = sock_gettstamp,
3803 .listen = mptcp_listen,
3804 .shutdown = inet_shutdown,
3805 .setsockopt = sock_common_setsockopt,
3806 .getsockopt = sock_common_getsockopt,
3807 .sendmsg = inet_sendmsg,
3808 .recvmsg = inet_recvmsg,
3809 .mmap = sock_no_mmap,
3810 .sendpage = inet_sendpage,
3811};
3812
3813static struct inet_protosw mptcp_protosw = {
3814 .type = SOCK_STREAM,
3815 .protocol = IPPROTO_MPTCP,
3816 .prot = &mptcp_prot,
3817 .ops = &mptcp_stream_ops,
3818 .flags = INET_PROTOSW_ICSK,
3819};
3820
3821static int mptcp_napi_poll(struct napi_struct *napi, int budget)
3822{
3823 struct mptcp_delegated_action *delegated;
3824 struct mptcp_subflow_context *subflow;
3825 int work_done = 0;
3826
3827 delegated = container_of(napi, struct mptcp_delegated_action, napi);
3828 while ((subflow = mptcp_subflow_delegated_next(delegated)) != NULL) {
3829 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3830
3831 bh_lock_sock_nested(ssk);
3832 if (!sock_owned_by_user(ssk) &&
3833 mptcp_subflow_has_delegated_action(subflow))
3834 mptcp_subflow_process_delegated(ssk);
3835 /* ... elsewhere tcp_release_cb_override already processed
3836 * the action or will do at next release_sock().
3837 * In both case must dequeue the subflow here - on the same
3838 * CPU that scheduled it.
3839 */
3840 bh_unlock_sock(ssk);
3841 sock_put(ssk);
3842
3843 if (++work_done == budget)
3844 return budget;
3845 }
3846
3847 /* always provide a 0 'work_done' argument, so that napi_complete_done
3848 * will not try accessing the NULL napi->dev ptr
3849 */
3850 napi_complete_done(napi, 0);
3851 return work_done;
3852}
3853
3854void __init mptcp_proto_init(void)
3855{
3856 struct mptcp_delegated_action *delegated;
3857 int cpu;
3858
3859 mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo;
3860
3861 if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL))
3862 panic("Failed to allocate MPTCP pcpu counter\n");
3863
3864 init_dummy_netdev(&mptcp_napi_dev);
3865 for_each_possible_cpu(cpu) {
3866 delegated = per_cpu_ptr(&mptcp_delegated_actions, cpu);
3867 INIT_LIST_HEAD(&delegated->head);
3868 netif_napi_add_tx(&mptcp_napi_dev, &delegated->napi,
3869 mptcp_napi_poll);
3870 napi_enable(&delegated->napi);
3871 }
3872
3873 mptcp_subflow_init();
3874 mptcp_pm_init();
3875 mptcp_token_init();
3876
3877 if (proto_register(&mptcp_prot, 1) != 0)
3878 panic("Failed to register MPTCP proto.\n");
3879
3880 inet_register_protosw(&mptcp_protosw);
3881
3882 BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb));
3883}
3884
3885#if IS_ENABLED(CONFIG_MPTCP_IPV6)
3886static const struct proto_ops mptcp_v6_stream_ops = {
3887 .family = PF_INET6,
3888 .owner = THIS_MODULE,
3889 .release = inet6_release,
3890 .bind = mptcp_bind,
3891 .connect = mptcp_stream_connect,
3892 .socketpair = sock_no_socketpair,
3893 .accept = mptcp_stream_accept,
3894 .getname = inet6_getname,
3895 .poll = mptcp_poll,
3896 .ioctl = inet6_ioctl,
3897 .gettstamp = sock_gettstamp,
3898 .listen = mptcp_listen,
3899 .shutdown = inet_shutdown,
3900 .setsockopt = sock_common_setsockopt,
3901 .getsockopt = sock_common_getsockopt,
3902 .sendmsg = inet6_sendmsg,
3903 .recvmsg = inet6_recvmsg,
3904 .mmap = sock_no_mmap,
3905 .sendpage = inet_sendpage,
3906#ifdef CONFIG_COMPAT
3907 .compat_ioctl = inet6_compat_ioctl,
3908#endif
3909};
3910
3911static struct proto mptcp_v6_prot;
3912
3913static struct inet_protosw mptcp_v6_protosw = {
3914 .type = SOCK_STREAM,
3915 .protocol = IPPROTO_MPTCP,
3916 .prot = &mptcp_v6_prot,
3917 .ops = &mptcp_v6_stream_ops,
3918 .flags = INET_PROTOSW_ICSK,
3919};
3920
3921int __init mptcp_proto_v6_init(void)
3922{
3923 int err;
3924
3925 mptcp_v6_prot = mptcp_prot;
3926 strcpy(mptcp_v6_prot.name, "MPTCPv6");
3927 mptcp_v6_prot.slab = NULL;
3928 mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock);
3929
3930 err = proto_register(&mptcp_v6_prot, 1);
3931 if (err)
3932 return err;
3933
3934 err = inet6_register_protosw(&mptcp_v6_protosw);
3935 if (err)
3936 proto_unregister(&mptcp_v6_prot);
3937
3938 return err;
3939}
3940#endif
1// SPDX-License-Identifier: GPL-2.0
2/* Multipath TCP
3 *
4 * Copyright (c) 2017 - 2019, Intel Corporation.
5 */
6
7#define pr_fmt(fmt) "MPTCP: " fmt
8
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/netdevice.h>
12#include <linux/sched/signal.h>
13#include <linux/atomic.h>
14#include <net/sock.h>
15#include <net/inet_common.h>
16#include <net/inet_hashtables.h>
17#include <net/protocol.h>
18#include <net/tcp_states.h>
19#if IS_ENABLED(CONFIG_MPTCP_IPV6)
20#include <net/transp_v6.h>
21#endif
22#include <net/mptcp.h>
23#include <net/xfrm.h>
24#include <asm/ioctls.h>
25#include "protocol.h"
26#include "mib.h"
27
28#define CREATE_TRACE_POINTS
29#include <trace/events/mptcp.h>
30
31#if IS_ENABLED(CONFIG_MPTCP_IPV6)
32struct mptcp6_sock {
33 struct mptcp_sock msk;
34 struct ipv6_pinfo np;
35};
36#endif
37
38enum {
39 MPTCP_CMSG_TS = BIT(0),
40 MPTCP_CMSG_INQ = BIT(1),
41};
42
43static struct percpu_counter mptcp_sockets_allocated ____cacheline_aligned_in_smp;
44
45static void __mptcp_destroy_sock(struct sock *sk);
46static void mptcp_check_send_data_fin(struct sock *sk);
47
48DEFINE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
49static struct net_device mptcp_napi_dev;
50
51/* Returns end sequence number of the receiver's advertised window */
52static u64 mptcp_wnd_end(const struct mptcp_sock *msk)
53{
54 return READ_ONCE(msk->wnd_end);
55}
56
57static const struct proto_ops *mptcp_fallback_tcp_ops(const struct sock *sk)
58{
59#if IS_ENABLED(CONFIG_MPTCP_IPV6)
60 if (sk->sk_prot == &tcpv6_prot)
61 return &inet6_stream_ops;
62#endif
63 WARN_ON_ONCE(sk->sk_prot != &tcp_prot);
64 return &inet_stream_ops;
65}
66
67static int __mptcp_socket_create(struct mptcp_sock *msk)
68{
69 struct mptcp_subflow_context *subflow;
70 struct sock *sk = (struct sock *)msk;
71 struct socket *ssock;
72 int err;
73
74 err = mptcp_subflow_create_socket(sk, sk->sk_family, &ssock);
75 if (err)
76 return err;
77
78 msk->scaling_ratio = tcp_sk(ssock->sk)->scaling_ratio;
79 WRITE_ONCE(msk->first, ssock->sk);
80 subflow = mptcp_subflow_ctx(ssock->sk);
81 list_add(&subflow->node, &msk->conn_list);
82 sock_hold(ssock->sk);
83 subflow->request_mptcp = 1;
84 subflow->subflow_id = msk->subflow_id++;
85
86 /* This is the first subflow, always with id 0 */
87 WRITE_ONCE(subflow->local_id, 0);
88 mptcp_sock_graft(msk->first, sk->sk_socket);
89 iput(SOCK_INODE(ssock));
90
91 return 0;
92}
93
94/* If the MPC handshake is not started, returns the first subflow,
95 * eventually allocating it.
96 */
97struct sock *__mptcp_nmpc_sk(struct mptcp_sock *msk)
98{
99 struct sock *sk = (struct sock *)msk;
100 int ret;
101
102 if (!((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
103 return ERR_PTR(-EINVAL);
104
105 if (!msk->first) {
106 ret = __mptcp_socket_create(msk);
107 if (ret)
108 return ERR_PTR(ret);
109 }
110
111 return msk->first;
112}
113
114static void mptcp_drop(struct sock *sk, struct sk_buff *skb)
115{
116 sk_drops_add(sk, skb);
117 __kfree_skb(skb);
118}
119
120static void mptcp_rmem_fwd_alloc_add(struct sock *sk, int size)
121{
122 WRITE_ONCE(mptcp_sk(sk)->rmem_fwd_alloc,
123 mptcp_sk(sk)->rmem_fwd_alloc + size);
124}
125
126static void mptcp_rmem_charge(struct sock *sk, int size)
127{
128 mptcp_rmem_fwd_alloc_add(sk, -size);
129}
130
131static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to,
132 struct sk_buff *from)
133{
134 bool fragstolen;
135 int delta;
136
137 if (MPTCP_SKB_CB(from)->offset ||
138 !skb_try_coalesce(to, from, &fragstolen, &delta))
139 return false;
140
141 pr_debug("colesced seq %llx into %llx new len %d new end seq %llx",
142 MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq,
143 to->len, MPTCP_SKB_CB(from)->end_seq);
144 MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq;
145
146 /* note the fwd memory can reach a negative value after accounting
147 * for the delta, but the later skb free will restore a non
148 * negative one
149 */
150 atomic_add(delta, &sk->sk_rmem_alloc);
151 mptcp_rmem_charge(sk, delta);
152 kfree_skb_partial(from, fragstolen);
153
154 return true;
155}
156
157static bool mptcp_ooo_try_coalesce(struct mptcp_sock *msk, struct sk_buff *to,
158 struct sk_buff *from)
159{
160 if (MPTCP_SKB_CB(from)->map_seq != MPTCP_SKB_CB(to)->end_seq)
161 return false;
162
163 return mptcp_try_coalesce((struct sock *)msk, to, from);
164}
165
166static void __mptcp_rmem_reclaim(struct sock *sk, int amount)
167{
168 amount >>= PAGE_SHIFT;
169 mptcp_rmem_charge(sk, amount << PAGE_SHIFT);
170 __sk_mem_reduce_allocated(sk, amount);
171}
172
173static void mptcp_rmem_uncharge(struct sock *sk, int size)
174{
175 struct mptcp_sock *msk = mptcp_sk(sk);
176 int reclaimable;
177
178 mptcp_rmem_fwd_alloc_add(sk, size);
179 reclaimable = msk->rmem_fwd_alloc - sk_unused_reserved_mem(sk);
180
181 /* see sk_mem_uncharge() for the rationale behind the following schema */
182 if (unlikely(reclaimable >= PAGE_SIZE))
183 __mptcp_rmem_reclaim(sk, reclaimable);
184}
185
186static void mptcp_rfree(struct sk_buff *skb)
187{
188 unsigned int len = skb->truesize;
189 struct sock *sk = skb->sk;
190
191 atomic_sub(len, &sk->sk_rmem_alloc);
192 mptcp_rmem_uncharge(sk, len);
193}
194
195void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk)
196{
197 skb_orphan(skb);
198 skb->sk = sk;
199 skb->destructor = mptcp_rfree;
200 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
201 mptcp_rmem_charge(sk, skb->truesize);
202}
203
204/* "inspired" by tcp_data_queue_ofo(), main differences:
205 * - use mptcp seqs
206 * - don't cope with sacks
207 */
208static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb)
209{
210 struct sock *sk = (struct sock *)msk;
211 struct rb_node **p, *parent;
212 u64 seq, end_seq, max_seq;
213 struct sk_buff *skb1;
214
215 seq = MPTCP_SKB_CB(skb)->map_seq;
216 end_seq = MPTCP_SKB_CB(skb)->end_seq;
217 max_seq = atomic64_read(&msk->rcv_wnd_sent);
218
219 pr_debug("msk=%p seq=%llx limit=%llx empty=%d", msk, seq, max_seq,
220 RB_EMPTY_ROOT(&msk->out_of_order_queue));
221 if (after64(end_seq, max_seq)) {
222 /* out of window */
223 mptcp_drop(sk, skb);
224 pr_debug("oow by %lld, rcv_wnd_sent %llu\n",
225 (unsigned long long)end_seq - (unsigned long)max_seq,
226 (unsigned long long)atomic64_read(&msk->rcv_wnd_sent));
227 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_NODSSWINDOW);
228 return;
229 }
230
231 p = &msk->out_of_order_queue.rb_node;
232 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUE);
233 if (RB_EMPTY_ROOT(&msk->out_of_order_queue)) {
234 rb_link_node(&skb->rbnode, NULL, p);
235 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
236 msk->ooo_last_skb = skb;
237 goto end;
238 }
239
240 /* with 2 subflows, adding at end of ooo queue is quite likely
241 * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup.
242 */
243 if (mptcp_ooo_try_coalesce(msk, msk->ooo_last_skb, skb)) {
244 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
245 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
246 return;
247 }
248
249 /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */
250 if (!before64(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) {
251 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
252 parent = &msk->ooo_last_skb->rbnode;
253 p = &parent->rb_right;
254 goto insert;
255 }
256
257 /* Find place to insert this segment. Handle overlaps on the way. */
258 parent = NULL;
259 while (*p) {
260 parent = *p;
261 skb1 = rb_to_skb(parent);
262 if (before64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
263 p = &parent->rb_left;
264 continue;
265 }
266 if (before64(seq, MPTCP_SKB_CB(skb1)->end_seq)) {
267 if (!after64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) {
268 /* All the bits are present. Drop. */
269 mptcp_drop(sk, skb);
270 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
271 return;
272 }
273 if (after64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
274 /* partial overlap:
275 * | skb |
276 * | skb1 |
277 * continue traversing
278 */
279 } else {
280 /* skb's seq == skb1's seq and skb covers skb1.
281 * Replace skb1 with skb.
282 */
283 rb_replace_node(&skb1->rbnode, &skb->rbnode,
284 &msk->out_of_order_queue);
285 mptcp_drop(sk, skb1);
286 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
287 goto merge_right;
288 }
289 } else if (mptcp_ooo_try_coalesce(msk, skb1, skb)) {
290 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
291 return;
292 }
293 p = &parent->rb_right;
294 }
295
296insert:
297 /* Insert segment into RB tree. */
298 rb_link_node(&skb->rbnode, parent, p);
299 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
300
301merge_right:
302 /* Remove other segments covered by skb. */
303 while ((skb1 = skb_rb_next(skb)) != NULL) {
304 if (before64(end_seq, MPTCP_SKB_CB(skb1)->end_seq))
305 break;
306 rb_erase(&skb1->rbnode, &msk->out_of_order_queue);
307 mptcp_drop(sk, skb1);
308 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
309 }
310 /* If there is no skb after us, we are the last_skb ! */
311 if (!skb1)
312 msk->ooo_last_skb = skb;
313
314end:
315 skb_condense(skb);
316 mptcp_set_owner_r(skb, sk);
317}
318
319static bool mptcp_rmem_schedule(struct sock *sk, struct sock *ssk, int size)
320{
321 struct mptcp_sock *msk = mptcp_sk(sk);
322 int amt, amount;
323
324 if (size <= msk->rmem_fwd_alloc)
325 return true;
326
327 size -= msk->rmem_fwd_alloc;
328 amt = sk_mem_pages(size);
329 amount = amt << PAGE_SHIFT;
330 if (!__sk_mem_raise_allocated(sk, size, amt, SK_MEM_RECV))
331 return false;
332
333 mptcp_rmem_fwd_alloc_add(sk, amount);
334 return true;
335}
336
337static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk,
338 struct sk_buff *skb, unsigned int offset,
339 size_t copy_len)
340{
341 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
342 struct sock *sk = (struct sock *)msk;
343 struct sk_buff *tail;
344 bool has_rxtstamp;
345
346 __skb_unlink(skb, &ssk->sk_receive_queue);
347
348 skb_ext_reset(skb);
349 skb_orphan(skb);
350
351 /* try to fetch required memory from subflow */
352 if (!mptcp_rmem_schedule(sk, ssk, skb->truesize))
353 goto drop;
354
355 has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp;
356
357 /* the skb map_seq accounts for the skb offset:
358 * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq
359 * value
360 */
361 MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow);
362 MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len;
363 MPTCP_SKB_CB(skb)->offset = offset;
364 MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp;
365
366 if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) {
367 /* in sequence */
368 msk->bytes_received += copy_len;
369 WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len);
370 tail = skb_peek_tail(&sk->sk_receive_queue);
371 if (tail && mptcp_try_coalesce(sk, tail, skb))
372 return true;
373
374 mptcp_set_owner_r(skb, sk);
375 __skb_queue_tail(&sk->sk_receive_queue, skb);
376 return true;
377 } else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) {
378 mptcp_data_queue_ofo(msk, skb);
379 return false;
380 }
381
382 /* old data, keep it simple and drop the whole pkt, sender
383 * will retransmit as needed, if needed.
384 */
385 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
386drop:
387 mptcp_drop(sk, skb);
388 return false;
389}
390
391static void mptcp_stop_rtx_timer(struct sock *sk)
392{
393 struct inet_connection_sock *icsk = inet_csk(sk);
394
395 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
396 mptcp_sk(sk)->timer_ival = 0;
397}
398
399static void mptcp_close_wake_up(struct sock *sk)
400{
401 if (sock_flag(sk, SOCK_DEAD))
402 return;
403
404 sk->sk_state_change(sk);
405 if (sk->sk_shutdown == SHUTDOWN_MASK ||
406 sk->sk_state == TCP_CLOSE)
407 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
408 else
409 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
410}
411
412/* called under the msk socket lock */
413static bool mptcp_pending_data_fin_ack(struct sock *sk)
414{
415 struct mptcp_sock *msk = mptcp_sk(sk);
416
417 return ((1 << sk->sk_state) &
418 (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) &&
419 msk->write_seq == READ_ONCE(msk->snd_una);
420}
421
422static void mptcp_check_data_fin_ack(struct sock *sk)
423{
424 struct mptcp_sock *msk = mptcp_sk(sk);
425
426 /* Look for an acknowledged DATA_FIN */
427 if (mptcp_pending_data_fin_ack(sk)) {
428 WRITE_ONCE(msk->snd_data_fin_enable, 0);
429
430 switch (sk->sk_state) {
431 case TCP_FIN_WAIT1:
432 mptcp_set_state(sk, TCP_FIN_WAIT2);
433 break;
434 case TCP_CLOSING:
435 case TCP_LAST_ACK:
436 mptcp_set_state(sk, TCP_CLOSE);
437 break;
438 }
439
440 mptcp_close_wake_up(sk);
441 }
442}
443
444/* can be called with no lock acquired */
445static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq)
446{
447 struct mptcp_sock *msk = mptcp_sk(sk);
448
449 if (READ_ONCE(msk->rcv_data_fin) &&
450 ((1 << inet_sk_state_load(sk)) &
451 (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) {
452 u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq);
453
454 if (READ_ONCE(msk->ack_seq) == rcv_data_fin_seq) {
455 if (seq)
456 *seq = rcv_data_fin_seq;
457
458 return true;
459 }
460 }
461
462 return false;
463}
464
465static void mptcp_set_datafin_timeout(struct sock *sk)
466{
467 struct inet_connection_sock *icsk = inet_csk(sk);
468 u32 retransmits;
469
470 retransmits = min_t(u32, icsk->icsk_retransmits,
471 ilog2(TCP_RTO_MAX / TCP_RTO_MIN));
472
473 mptcp_sk(sk)->timer_ival = TCP_RTO_MIN << retransmits;
474}
475
476static void __mptcp_set_timeout(struct sock *sk, long tout)
477{
478 mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
479}
480
481static long mptcp_timeout_from_subflow(const struct mptcp_subflow_context *subflow)
482{
483 const struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
484
485 return inet_csk(ssk)->icsk_pending && !subflow->stale_count ?
486 inet_csk(ssk)->icsk_timeout - jiffies : 0;
487}
488
489static void mptcp_set_timeout(struct sock *sk)
490{
491 struct mptcp_subflow_context *subflow;
492 long tout = 0;
493
494 mptcp_for_each_subflow(mptcp_sk(sk), subflow)
495 tout = max(tout, mptcp_timeout_from_subflow(subflow));
496 __mptcp_set_timeout(sk, tout);
497}
498
499static inline bool tcp_can_send_ack(const struct sock *ssk)
500{
501 return !((1 << inet_sk_state_load(ssk)) &
502 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE | TCPF_LISTEN));
503}
504
505void __mptcp_subflow_send_ack(struct sock *ssk)
506{
507 if (tcp_can_send_ack(ssk))
508 tcp_send_ack(ssk);
509}
510
511static void mptcp_subflow_send_ack(struct sock *ssk)
512{
513 bool slow;
514
515 slow = lock_sock_fast(ssk);
516 __mptcp_subflow_send_ack(ssk);
517 unlock_sock_fast(ssk, slow);
518}
519
520static void mptcp_send_ack(struct mptcp_sock *msk)
521{
522 struct mptcp_subflow_context *subflow;
523
524 mptcp_for_each_subflow(msk, subflow)
525 mptcp_subflow_send_ack(mptcp_subflow_tcp_sock(subflow));
526}
527
528static void mptcp_subflow_cleanup_rbuf(struct sock *ssk)
529{
530 bool slow;
531
532 slow = lock_sock_fast(ssk);
533 if (tcp_can_send_ack(ssk))
534 tcp_cleanup_rbuf(ssk, 1);
535 unlock_sock_fast(ssk, slow);
536}
537
538static bool mptcp_subflow_could_cleanup(const struct sock *ssk, bool rx_empty)
539{
540 const struct inet_connection_sock *icsk = inet_csk(ssk);
541 u8 ack_pending = READ_ONCE(icsk->icsk_ack.pending);
542 const struct tcp_sock *tp = tcp_sk(ssk);
543
544 return (ack_pending & ICSK_ACK_SCHED) &&
545 ((READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->rcv_wup) >
546 READ_ONCE(icsk->icsk_ack.rcv_mss)) ||
547 (rx_empty && ack_pending &
548 (ICSK_ACK_PUSHED2 | ICSK_ACK_PUSHED)));
549}
550
551static void mptcp_cleanup_rbuf(struct mptcp_sock *msk)
552{
553 int old_space = READ_ONCE(msk->old_wspace);
554 struct mptcp_subflow_context *subflow;
555 struct sock *sk = (struct sock *)msk;
556 int space = __mptcp_space(sk);
557 bool cleanup, rx_empty;
558
559 cleanup = (space > 0) && (space >= (old_space << 1));
560 rx_empty = !__mptcp_rmem(sk);
561
562 mptcp_for_each_subflow(msk, subflow) {
563 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
564
565 if (cleanup || mptcp_subflow_could_cleanup(ssk, rx_empty))
566 mptcp_subflow_cleanup_rbuf(ssk);
567 }
568}
569
570static bool mptcp_check_data_fin(struct sock *sk)
571{
572 struct mptcp_sock *msk = mptcp_sk(sk);
573 u64 rcv_data_fin_seq;
574 bool ret = false;
575
576 /* Need to ack a DATA_FIN received from a peer while this side
577 * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2.
578 * msk->rcv_data_fin was set when parsing the incoming options
579 * at the subflow level and the msk lock was not held, so this
580 * is the first opportunity to act on the DATA_FIN and change
581 * the msk state.
582 *
583 * If we are caught up to the sequence number of the incoming
584 * DATA_FIN, send the DATA_ACK now and do state transition. If
585 * not caught up, do nothing and let the recv code send DATA_ACK
586 * when catching up.
587 */
588
589 if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) {
590 WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1);
591 WRITE_ONCE(msk->rcv_data_fin, 0);
592
593 WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | RCV_SHUTDOWN);
594 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
595
596 switch (sk->sk_state) {
597 case TCP_ESTABLISHED:
598 mptcp_set_state(sk, TCP_CLOSE_WAIT);
599 break;
600 case TCP_FIN_WAIT1:
601 mptcp_set_state(sk, TCP_CLOSING);
602 break;
603 case TCP_FIN_WAIT2:
604 mptcp_set_state(sk, TCP_CLOSE);
605 break;
606 default:
607 /* Other states not expected */
608 WARN_ON_ONCE(1);
609 break;
610 }
611
612 ret = true;
613 if (!__mptcp_check_fallback(msk))
614 mptcp_send_ack(msk);
615 mptcp_close_wake_up(sk);
616 }
617 return ret;
618}
619
620static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
621 struct sock *ssk,
622 unsigned int *bytes)
623{
624 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
625 struct sock *sk = (struct sock *)msk;
626 unsigned int moved = 0;
627 bool more_data_avail;
628 struct tcp_sock *tp;
629 bool done = false;
630 int sk_rbuf;
631
632 sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
633
634 if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
635 int ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
636
637 if (unlikely(ssk_rbuf > sk_rbuf)) {
638 WRITE_ONCE(sk->sk_rcvbuf, ssk_rbuf);
639 sk_rbuf = ssk_rbuf;
640 }
641 }
642
643 pr_debug("msk=%p ssk=%p", msk, ssk);
644 tp = tcp_sk(ssk);
645 do {
646 u32 map_remaining, offset;
647 u32 seq = tp->copied_seq;
648 struct sk_buff *skb;
649 bool fin;
650
651 /* try to move as much data as available */
652 map_remaining = subflow->map_data_len -
653 mptcp_subflow_get_map_offset(subflow);
654
655 skb = skb_peek(&ssk->sk_receive_queue);
656 if (!skb) {
657 /* With racing move_skbs_to_msk() and __mptcp_move_skbs(),
658 * a different CPU can have already processed the pending
659 * data, stop here or we can enter an infinite loop
660 */
661 if (!moved)
662 done = true;
663 break;
664 }
665
666 if (__mptcp_check_fallback(msk)) {
667 /* Under fallback skbs have no MPTCP extension and TCP could
668 * collapse them between the dummy map creation and the
669 * current dequeue. Be sure to adjust the map size.
670 */
671 map_remaining = skb->len;
672 subflow->map_data_len = skb->len;
673 }
674
675 offset = seq - TCP_SKB_CB(skb)->seq;
676 fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
677 if (fin) {
678 done = true;
679 seq++;
680 }
681
682 if (offset < skb->len) {
683 size_t len = skb->len - offset;
684
685 if (tp->urg_data)
686 done = true;
687
688 if (__mptcp_move_skb(msk, ssk, skb, offset, len))
689 moved += len;
690 seq += len;
691
692 if (WARN_ON_ONCE(map_remaining < len))
693 break;
694 } else {
695 WARN_ON_ONCE(!fin);
696 sk_eat_skb(ssk, skb);
697 done = true;
698 }
699
700 WRITE_ONCE(tp->copied_seq, seq);
701 more_data_avail = mptcp_subflow_data_available(ssk);
702
703 if (atomic_read(&sk->sk_rmem_alloc) > sk_rbuf) {
704 done = true;
705 break;
706 }
707 } while (more_data_avail);
708
709 *bytes += moved;
710 return done;
711}
712
713static bool __mptcp_ofo_queue(struct mptcp_sock *msk)
714{
715 struct sock *sk = (struct sock *)msk;
716 struct sk_buff *skb, *tail;
717 bool moved = false;
718 struct rb_node *p;
719 u64 end_seq;
720
721 p = rb_first(&msk->out_of_order_queue);
722 pr_debug("msk=%p empty=%d", msk, RB_EMPTY_ROOT(&msk->out_of_order_queue));
723 while (p) {
724 skb = rb_to_skb(p);
725 if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq))
726 break;
727
728 p = rb_next(p);
729 rb_erase(&skb->rbnode, &msk->out_of_order_queue);
730
731 if (unlikely(!after64(MPTCP_SKB_CB(skb)->end_seq,
732 msk->ack_seq))) {
733 mptcp_drop(sk, skb);
734 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
735 continue;
736 }
737
738 end_seq = MPTCP_SKB_CB(skb)->end_seq;
739 tail = skb_peek_tail(&sk->sk_receive_queue);
740 if (!tail || !mptcp_ooo_try_coalesce(msk, tail, skb)) {
741 int delta = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq;
742
743 /* skip overlapping data, if any */
744 pr_debug("uncoalesced seq=%llx ack seq=%llx delta=%d",
745 MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq,
746 delta);
747 MPTCP_SKB_CB(skb)->offset += delta;
748 MPTCP_SKB_CB(skb)->map_seq += delta;
749 __skb_queue_tail(&sk->sk_receive_queue, skb);
750 }
751 msk->bytes_received += end_seq - msk->ack_seq;
752 WRITE_ONCE(msk->ack_seq, end_seq);
753 moved = true;
754 }
755 return moved;
756}
757
758static bool __mptcp_subflow_error_report(struct sock *sk, struct sock *ssk)
759{
760 int err = sock_error(ssk);
761 int ssk_state;
762
763 if (!err)
764 return false;
765
766 /* only propagate errors on fallen-back sockets or
767 * on MPC connect
768 */
769 if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(mptcp_sk(sk)))
770 return false;
771
772 /* We need to propagate only transition to CLOSE state.
773 * Orphaned socket will see such state change via
774 * subflow_sched_work_if_closed() and that path will properly
775 * destroy the msk as needed.
776 */
777 ssk_state = inet_sk_state_load(ssk);
778 if (ssk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DEAD))
779 mptcp_set_state(sk, ssk_state);
780 WRITE_ONCE(sk->sk_err, -err);
781
782 /* This barrier is coupled with smp_rmb() in mptcp_poll() */
783 smp_wmb();
784 sk_error_report(sk);
785 return true;
786}
787
788void __mptcp_error_report(struct sock *sk)
789{
790 struct mptcp_subflow_context *subflow;
791 struct mptcp_sock *msk = mptcp_sk(sk);
792
793 mptcp_for_each_subflow(msk, subflow)
794 if (__mptcp_subflow_error_report(sk, mptcp_subflow_tcp_sock(subflow)))
795 break;
796}
797
798/* In most cases we will be able to lock the mptcp socket. If its already
799 * owned, we need to defer to the work queue to avoid ABBA deadlock.
800 */
801static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk)
802{
803 struct sock *sk = (struct sock *)msk;
804 unsigned int moved = 0;
805
806 __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
807 __mptcp_ofo_queue(msk);
808 if (unlikely(ssk->sk_err)) {
809 if (!sock_owned_by_user(sk))
810 __mptcp_error_report(sk);
811 else
812 __set_bit(MPTCP_ERROR_REPORT, &msk->cb_flags);
813 }
814
815 /* If the moves have caught up with the DATA_FIN sequence number
816 * it's time to ack the DATA_FIN and change socket state, but
817 * this is not a good place to change state. Let the workqueue
818 * do it.
819 */
820 if (mptcp_pending_data_fin(sk, NULL))
821 mptcp_schedule_work(sk);
822 return moved > 0;
823}
824
825void mptcp_data_ready(struct sock *sk, struct sock *ssk)
826{
827 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
828 struct mptcp_sock *msk = mptcp_sk(sk);
829 int sk_rbuf, ssk_rbuf;
830
831 /* The peer can send data while we are shutting down this
832 * subflow at msk destruction time, but we must avoid enqueuing
833 * more data to the msk receive queue
834 */
835 if (unlikely(subflow->disposable))
836 return;
837
838 ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
839 sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
840 if (unlikely(ssk_rbuf > sk_rbuf))
841 sk_rbuf = ssk_rbuf;
842
843 /* over limit? can't append more skbs to msk, Also, no need to wake-up*/
844 if (__mptcp_rmem(sk) > sk_rbuf) {
845 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED);
846 return;
847 }
848
849 /* Wake-up the reader only for in-sequence data */
850 mptcp_data_lock(sk);
851 if (move_skbs_to_msk(msk, ssk) && mptcp_epollin_ready(sk))
852 sk->sk_data_ready(sk);
853 mptcp_data_unlock(sk);
854}
855
856static void mptcp_subflow_joined(struct mptcp_sock *msk, struct sock *ssk)
857{
858 mptcp_subflow_ctx(ssk)->map_seq = READ_ONCE(msk->ack_seq);
859 WRITE_ONCE(msk->allow_infinite_fallback, false);
860 mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC);
861}
862
863static bool __mptcp_finish_join(struct mptcp_sock *msk, struct sock *ssk)
864{
865 struct sock *sk = (struct sock *)msk;
866
867 if (sk->sk_state != TCP_ESTABLISHED)
868 return false;
869
870 /* attach to msk socket only after we are sure we will deal with it
871 * at close time
872 */
873 if (sk->sk_socket && !ssk->sk_socket)
874 mptcp_sock_graft(ssk, sk->sk_socket);
875
876 mptcp_subflow_ctx(ssk)->subflow_id = msk->subflow_id++;
877 mptcp_sockopt_sync_locked(msk, ssk);
878 mptcp_subflow_joined(msk, ssk);
879 mptcp_stop_tout_timer(sk);
880 __mptcp_propagate_sndbuf(sk, ssk);
881 return true;
882}
883
884static void __mptcp_flush_join_list(struct sock *sk, struct list_head *join_list)
885{
886 struct mptcp_subflow_context *tmp, *subflow;
887 struct mptcp_sock *msk = mptcp_sk(sk);
888
889 list_for_each_entry_safe(subflow, tmp, join_list, node) {
890 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
891 bool slow = lock_sock_fast(ssk);
892
893 list_move_tail(&subflow->node, &msk->conn_list);
894 if (!__mptcp_finish_join(msk, ssk))
895 mptcp_subflow_reset(ssk);
896 unlock_sock_fast(ssk, slow);
897 }
898}
899
900static bool mptcp_rtx_timer_pending(struct sock *sk)
901{
902 return timer_pending(&inet_csk(sk)->icsk_retransmit_timer);
903}
904
905static void mptcp_reset_rtx_timer(struct sock *sk)
906{
907 struct inet_connection_sock *icsk = inet_csk(sk);
908 unsigned long tout;
909
910 /* prevent rescheduling on close */
911 if (unlikely(inet_sk_state_load(sk) == TCP_CLOSE))
912 return;
913
914 tout = mptcp_sk(sk)->timer_ival;
915 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout);
916}
917
918bool mptcp_schedule_work(struct sock *sk)
919{
920 if (inet_sk_state_load(sk) != TCP_CLOSE &&
921 schedule_work(&mptcp_sk(sk)->work)) {
922 /* each subflow already holds a reference to the sk, and the
923 * workqueue is invoked by a subflow, so sk can't go away here.
924 */
925 sock_hold(sk);
926 return true;
927 }
928 return false;
929}
930
931static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk)
932{
933 struct mptcp_subflow_context *subflow;
934
935 msk_owned_by_me(msk);
936
937 mptcp_for_each_subflow(msk, subflow) {
938 if (READ_ONCE(subflow->data_avail))
939 return mptcp_subflow_tcp_sock(subflow);
940 }
941
942 return NULL;
943}
944
945static bool mptcp_skb_can_collapse_to(u64 write_seq,
946 const struct sk_buff *skb,
947 const struct mptcp_ext *mpext)
948{
949 if (!tcp_skb_can_collapse_to(skb))
950 return false;
951
952 /* can collapse only if MPTCP level sequence is in order and this
953 * mapping has not been xmitted yet
954 */
955 return mpext && mpext->data_seq + mpext->data_len == write_seq &&
956 !mpext->frozen;
957}
958
959/* we can append data to the given data frag if:
960 * - there is space available in the backing page_frag
961 * - the data frag tail matches the current page_frag free offset
962 * - the data frag end sequence number matches the current write seq
963 */
964static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk,
965 const struct page_frag *pfrag,
966 const struct mptcp_data_frag *df)
967{
968 return df && pfrag->page == df->page &&
969 pfrag->size - pfrag->offset > 0 &&
970 pfrag->offset == (df->offset + df->data_len) &&
971 df->data_seq + df->data_len == msk->write_seq;
972}
973
974static void dfrag_uncharge(struct sock *sk, int len)
975{
976 sk_mem_uncharge(sk, len);
977 sk_wmem_queued_add(sk, -len);
978}
979
980static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag)
981{
982 int len = dfrag->data_len + dfrag->overhead;
983
984 list_del(&dfrag->list);
985 dfrag_uncharge(sk, len);
986 put_page(dfrag->page);
987}
988
989/* called under both the msk socket lock and the data lock */
990static void __mptcp_clean_una(struct sock *sk)
991{
992 struct mptcp_sock *msk = mptcp_sk(sk);
993 struct mptcp_data_frag *dtmp, *dfrag;
994 u64 snd_una;
995
996 snd_una = msk->snd_una;
997 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) {
998 if (after64(dfrag->data_seq + dfrag->data_len, snd_una))
999 break;
1000
1001 if (unlikely(dfrag == msk->first_pending)) {
1002 /* in recovery mode can see ack after the current snd head */
1003 if (WARN_ON_ONCE(!msk->recovery))
1004 break;
1005
1006 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1007 }
1008
1009 dfrag_clear(sk, dfrag);
1010 }
1011
1012 dfrag = mptcp_rtx_head(sk);
1013 if (dfrag && after64(snd_una, dfrag->data_seq)) {
1014 u64 delta = snd_una - dfrag->data_seq;
1015
1016 /* prevent wrap around in recovery mode */
1017 if (unlikely(delta > dfrag->already_sent)) {
1018 if (WARN_ON_ONCE(!msk->recovery))
1019 goto out;
1020 if (WARN_ON_ONCE(delta > dfrag->data_len))
1021 goto out;
1022 dfrag->already_sent += delta - dfrag->already_sent;
1023 }
1024
1025 dfrag->data_seq += delta;
1026 dfrag->offset += delta;
1027 dfrag->data_len -= delta;
1028 dfrag->already_sent -= delta;
1029
1030 dfrag_uncharge(sk, delta);
1031 }
1032
1033 /* all retransmitted data acked, recovery completed */
1034 if (unlikely(msk->recovery) && after64(msk->snd_una, msk->recovery_snd_nxt))
1035 msk->recovery = false;
1036
1037out:
1038 if (snd_una == msk->snd_nxt && snd_una == msk->write_seq) {
1039 if (mptcp_rtx_timer_pending(sk) && !mptcp_data_fin_enabled(msk))
1040 mptcp_stop_rtx_timer(sk);
1041 } else {
1042 mptcp_reset_rtx_timer(sk);
1043 }
1044
1045 if (mptcp_pending_data_fin_ack(sk))
1046 mptcp_schedule_work(sk);
1047}
1048
1049static void __mptcp_clean_una_wakeup(struct sock *sk)
1050{
1051 lockdep_assert_held_once(&sk->sk_lock.slock);
1052
1053 __mptcp_clean_una(sk);
1054 mptcp_write_space(sk);
1055}
1056
1057static void mptcp_clean_una_wakeup(struct sock *sk)
1058{
1059 mptcp_data_lock(sk);
1060 __mptcp_clean_una_wakeup(sk);
1061 mptcp_data_unlock(sk);
1062}
1063
1064static void mptcp_enter_memory_pressure(struct sock *sk)
1065{
1066 struct mptcp_subflow_context *subflow;
1067 struct mptcp_sock *msk = mptcp_sk(sk);
1068 bool first = true;
1069
1070 mptcp_for_each_subflow(msk, subflow) {
1071 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
1072
1073 if (first)
1074 tcp_enter_memory_pressure(ssk);
1075 sk_stream_moderate_sndbuf(ssk);
1076
1077 first = false;
1078 }
1079 __mptcp_sync_sndbuf(sk);
1080}
1081
1082/* ensure we get enough memory for the frag hdr, beyond some minimal amount of
1083 * data
1084 */
1085static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag)
1086{
1087 if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag),
1088 pfrag, sk->sk_allocation)))
1089 return true;
1090
1091 mptcp_enter_memory_pressure(sk);
1092 return false;
1093}
1094
1095static struct mptcp_data_frag *
1096mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag,
1097 int orig_offset)
1098{
1099 int offset = ALIGN(orig_offset, sizeof(long));
1100 struct mptcp_data_frag *dfrag;
1101
1102 dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset);
1103 dfrag->data_len = 0;
1104 dfrag->data_seq = msk->write_seq;
1105 dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag);
1106 dfrag->offset = offset + sizeof(struct mptcp_data_frag);
1107 dfrag->already_sent = 0;
1108 dfrag->page = pfrag->page;
1109
1110 return dfrag;
1111}
1112
1113struct mptcp_sendmsg_info {
1114 int mss_now;
1115 int size_goal;
1116 u16 limit;
1117 u16 sent;
1118 unsigned int flags;
1119 bool data_lock_held;
1120};
1121
1122static int mptcp_check_allowed_size(const struct mptcp_sock *msk, struct sock *ssk,
1123 u64 data_seq, int avail_size)
1124{
1125 u64 window_end = mptcp_wnd_end(msk);
1126 u64 mptcp_snd_wnd;
1127
1128 if (__mptcp_check_fallback(msk))
1129 return avail_size;
1130
1131 mptcp_snd_wnd = window_end - data_seq;
1132 avail_size = min_t(unsigned int, mptcp_snd_wnd, avail_size);
1133
1134 if (unlikely(tcp_sk(ssk)->snd_wnd < mptcp_snd_wnd)) {
1135 tcp_sk(ssk)->snd_wnd = min_t(u64, U32_MAX, mptcp_snd_wnd);
1136 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_SNDWNDSHARED);
1137 }
1138
1139 return avail_size;
1140}
1141
1142static bool __mptcp_add_ext(struct sk_buff *skb, gfp_t gfp)
1143{
1144 struct skb_ext *mpext = __skb_ext_alloc(gfp);
1145
1146 if (!mpext)
1147 return false;
1148 __skb_ext_set(skb, SKB_EXT_MPTCP, mpext);
1149 return true;
1150}
1151
1152static struct sk_buff *__mptcp_do_alloc_tx_skb(struct sock *sk, gfp_t gfp)
1153{
1154 struct sk_buff *skb;
1155
1156 skb = alloc_skb_fclone(MAX_TCP_HEADER, gfp);
1157 if (likely(skb)) {
1158 if (likely(__mptcp_add_ext(skb, gfp))) {
1159 skb_reserve(skb, MAX_TCP_HEADER);
1160 skb->ip_summed = CHECKSUM_PARTIAL;
1161 INIT_LIST_HEAD(&skb->tcp_tsorted_anchor);
1162 return skb;
1163 }
1164 __kfree_skb(skb);
1165 } else {
1166 mptcp_enter_memory_pressure(sk);
1167 }
1168 return NULL;
1169}
1170
1171static struct sk_buff *__mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, gfp_t gfp)
1172{
1173 struct sk_buff *skb;
1174
1175 skb = __mptcp_do_alloc_tx_skb(sk, gfp);
1176 if (!skb)
1177 return NULL;
1178
1179 if (likely(sk_wmem_schedule(ssk, skb->truesize))) {
1180 tcp_skb_entail(ssk, skb);
1181 return skb;
1182 }
1183 tcp_skb_tsorted_anchor_cleanup(skb);
1184 kfree_skb(skb);
1185 return NULL;
1186}
1187
1188static struct sk_buff *mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, bool data_lock_held)
1189{
1190 gfp_t gfp = data_lock_held ? GFP_ATOMIC : sk->sk_allocation;
1191
1192 return __mptcp_alloc_tx_skb(sk, ssk, gfp);
1193}
1194
1195/* note: this always recompute the csum on the whole skb, even
1196 * if we just appended a single frag. More status info needed
1197 */
1198static void mptcp_update_data_checksum(struct sk_buff *skb, int added)
1199{
1200 struct mptcp_ext *mpext = mptcp_get_ext(skb);
1201 __wsum csum = ~csum_unfold(mpext->csum);
1202 int offset = skb->len - added;
1203
1204 mpext->csum = csum_fold(csum_block_add(csum, skb_checksum(skb, offset, added, 0), offset));
1205}
1206
1207static void mptcp_update_infinite_map(struct mptcp_sock *msk,
1208 struct sock *ssk,
1209 struct mptcp_ext *mpext)
1210{
1211 if (!mpext)
1212 return;
1213
1214 mpext->infinite_map = 1;
1215 mpext->data_len = 0;
1216
1217 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPTX);
1218 mptcp_subflow_ctx(ssk)->send_infinite_map = 0;
1219 pr_fallback(msk);
1220 mptcp_do_fallback(ssk);
1221}
1222
1223#define MPTCP_MAX_GSO_SIZE (GSO_LEGACY_MAX_SIZE - (MAX_TCP_HEADER + 1))
1224
1225static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
1226 struct mptcp_data_frag *dfrag,
1227 struct mptcp_sendmsg_info *info)
1228{
1229 u64 data_seq = dfrag->data_seq + info->sent;
1230 int offset = dfrag->offset + info->sent;
1231 struct mptcp_sock *msk = mptcp_sk(sk);
1232 bool zero_window_probe = false;
1233 struct mptcp_ext *mpext = NULL;
1234 bool can_coalesce = false;
1235 bool reuse_skb = true;
1236 struct sk_buff *skb;
1237 size_t copy;
1238 int i;
1239
1240 pr_debug("msk=%p ssk=%p sending dfrag at seq=%llu len=%u already sent=%u",
1241 msk, ssk, dfrag->data_seq, dfrag->data_len, info->sent);
1242
1243 if (WARN_ON_ONCE(info->sent > info->limit ||
1244 info->limit > dfrag->data_len))
1245 return 0;
1246
1247 if (unlikely(!__tcp_can_send(ssk)))
1248 return -EAGAIN;
1249
1250 /* compute send limit */
1251 if (unlikely(ssk->sk_gso_max_size > MPTCP_MAX_GSO_SIZE))
1252 ssk->sk_gso_max_size = MPTCP_MAX_GSO_SIZE;
1253 info->mss_now = tcp_send_mss(ssk, &info->size_goal, info->flags);
1254 copy = info->size_goal;
1255
1256 skb = tcp_write_queue_tail(ssk);
1257 if (skb && copy > skb->len) {
1258 /* Limit the write to the size available in the
1259 * current skb, if any, so that we create at most a new skb.
1260 * Explicitly tells TCP internals to avoid collapsing on later
1261 * queue management operation, to avoid breaking the ext <->
1262 * SSN association set here
1263 */
1264 mpext = mptcp_get_ext(skb);
1265 if (!mptcp_skb_can_collapse_to(data_seq, skb, mpext)) {
1266 TCP_SKB_CB(skb)->eor = 1;
1267 tcp_mark_push(tcp_sk(ssk), skb);
1268 goto alloc_skb;
1269 }
1270
1271 i = skb_shinfo(skb)->nr_frags;
1272 can_coalesce = skb_can_coalesce(skb, i, dfrag->page, offset);
1273 if (!can_coalesce && i >= READ_ONCE(sysctl_max_skb_frags)) {
1274 tcp_mark_push(tcp_sk(ssk), skb);
1275 goto alloc_skb;
1276 }
1277
1278 copy -= skb->len;
1279 } else {
1280alloc_skb:
1281 skb = mptcp_alloc_tx_skb(sk, ssk, info->data_lock_held);
1282 if (!skb)
1283 return -ENOMEM;
1284
1285 i = skb_shinfo(skb)->nr_frags;
1286 reuse_skb = false;
1287 mpext = mptcp_get_ext(skb);
1288 }
1289
1290 /* Zero window and all data acked? Probe. */
1291 copy = mptcp_check_allowed_size(msk, ssk, data_seq, copy);
1292 if (copy == 0) {
1293 u64 snd_una = READ_ONCE(msk->snd_una);
1294
1295 if (snd_una != msk->snd_nxt || tcp_write_queue_tail(ssk)) {
1296 tcp_remove_empty_skb(ssk);
1297 return 0;
1298 }
1299
1300 zero_window_probe = true;
1301 data_seq = snd_una - 1;
1302 copy = 1;
1303 }
1304
1305 copy = min_t(size_t, copy, info->limit - info->sent);
1306 if (!sk_wmem_schedule(ssk, copy)) {
1307 tcp_remove_empty_skb(ssk);
1308 return -ENOMEM;
1309 }
1310
1311 if (can_coalesce) {
1312 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1313 } else {
1314 get_page(dfrag->page);
1315 skb_fill_page_desc(skb, i, dfrag->page, offset, copy);
1316 }
1317
1318 skb->len += copy;
1319 skb->data_len += copy;
1320 skb->truesize += copy;
1321 sk_wmem_queued_add(ssk, copy);
1322 sk_mem_charge(ssk, copy);
1323 WRITE_ONCE(tcp_sk(ssk)->write_seq, tcp_sk(ssk)->write_seq + copy);
1324 TCP_SKB_CB(skb)->end_seq += copy;
1325 tcp_skb_pcount_set(skb, 0);
1326
1327 /* on skb reuse we just need to update the DSS len */
1328 if (reuse_skb) {
1329 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1330 mpext->data_len += copy;
1331 goto out;
1332 }
1333
1334 memset(mpext, 0, sizeof(*mpext));
1335 mpext->data_seq = data_seq;
1336 mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq;
1337 mpext->data_len = copy;
1338 mpext->use_map = 1;
1339 mpext->dsn64 = 1;
1340
1341 pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d",
1342 mpext->data_seq, mpext->subflow_seq, mpext->data_len,
1343 mpext->dsn64);
1344
1345 if (zero_window_probe) {
1346 mptcp_subflow_ctx(ssk)->rel_write_seq += copy;
1347 mpext->frozen = 1;
1348 if (READ_ONCE(msk->csum_enabled))
1349 mptcp_update_data_checksum(skb, copy);
1350 tcp_push_pending_frames(ssk);
1351 return 0;
1352 }
1353out:
1354 if (READ_ONCE(msk->csum_enabled))
1355 mptcp_update_data_checksum(skb, copy);
1356 if (mptcp_subflow_ctx(ssk)->send_infinite_map)
1357 mptcp_update_infinite_map(msk, ssk, mpext);
1358 trace_mptcp_sendmsg_frag(mpext);
1359 mptcp_subflow_ctx(ssk)->rel_write_seq += copy;
1360 return copy;
1361}
1362
1363#define MPTCP_SEND_BURST_SIZE ((1 << 16) - \
1364 sizeof(struct tcphdr) - \
1365 MAX_TCP_OPTION_SPACE - \
1366 sizeof(struct ipv6hdr) - \
1367 sizeof(struct frag_hdr))
1368
1369struct subflow_send_info {
1370 struct sock *ssk;
1371 u64 linger_time;
1372};
1373
1374void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow)
1375{
1376 if (!subflow->stale)
1377 return;
1378
1379 subflow->stale = 0;
1380 MPTCP_INC_STATS(sock_net(mptcp_subflow_tcp_sock(subflow)), MPTCP_MIB_SUBFLOWRECOVER);
1381}
1382
1383bool mptcp_subflow_active(struct mptcp_subflow_context *subflow)
1384{
1385 if (unlikely(subflow->stale)) {
1386 u32 rcv_tstamp = READ_ONCE(tcp_sk(mptcp_subflow_tcp_sock(subflow))->rcv_tstamp);
1387
1388 if (subflow->stale_rcv_tstamp == rcv_tstamp)
1389 return false;
1390
1391 mptcp_subflow_set_active(subflow);
1392 }
1393 return __mptcp_subflow_active(subflow);
1394}
1395
1396#define SSK_MODE_ACTIVE 0
1397#define SSK_MODE_BACKUP 1
1398#define SSK_MODE_MAX 2
1399
1400/* implement the mptcp packet scheduler;
1401 * returns the subflow that will transmit the next DSS
1402 * additionally updates the rtx timeout
1403 */
1404struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk)
1405{
1406 struct subflow_send_info send_info[SSK_MODE_MAX];
1407 struct mptcp_subflow_context *subflow;
1408 struct sock *sk = (struct sock *)msk;
1409 u32 pace, burst, wmem;
1410 int i, nr_active = 0;
1411 struct sock *ssk;
1412 u64 linger_time;
1413 long tout = 0;
1414
1415 /* pick the subflow with the lower wmem/wspace ratio */
1416 for (i = 0; i < SSK_MODE_MAX; ++i) {
1417 send_info[i].ssk = NULL;
1418 send_info[i].linger_time = -1;
1419 }
1420
1421 mptcp_for_each_subflow(msk, subflow) {
1422 trace_mptcp_subflow_get_send(subflow);
1423 ssk = mptcp_subflow_tcp_sock(subflow);
1424 if (!mptcp_subflow_active(subflow))
1425 continue;
1426
1427 tout = max(tout, mptcp_timeout_from_subflow(subflow));
1428 nr_active += !subflow->backup;
1429 pace = subflow->avg_pacing_rate;
1430 if (unlikely(!pace)) {
1431 /* init pacing rate from socket */
1432 subflow->avg_pacing_rate = READ_ONCE(ssk->sk_pacing_rate);
1433 pace = subflow->avg_pacing_rate;
1434 if (!pace)
1435 continue;
1436 }
1437
1438 linger_time = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32, pace);
1439 if (linger_time < send_info[subflow->backup].linger_time) {
1440 send_info[subflow->backup].ssk = ssk;
1441 send_info[subflow->backup].linger_time = linger_time;
1442 }
1443 }
1444 __mptcp_set_timeout(sk, tout);
1445
1446 /* pick the best backup if no other subflow is active */
1447 if (!nr_active)
1448 send_info[SSK_MODE_ACTIVE].ssk = send_info[SSK_MODE_BACKUP].ssk;
1449
1450 /* According to the blest algorithm, to avoid HoL blocking for the
1451 * faster flow, we need to:
1452 * - estimate the faster flow linger time
1453 * - use the above to estimate the amount of byte transferred
1454 * by the faster flow
1455 * - check that the amount of queued data is greter than the above,
1456 * otherwise do not use the picked, slower, subflow
1457 * We select the subflow with the shorter estimated time to flush
1458 * the queued mem, which basically ensure the above. We just need
1459 * to check that subflow has a non empty cwin.
1460 */
1461 ssk = send_info[SSK_MODE_ACTIVE].ssk;
1462 if (!ssk || !sk_stream_memory_free(ssk))
1463 return NULL;
1464
1465 burst = min_t(int, MPTCP_SEND_BURST_SIZE, mptcp_wnd_end(msk) - msk->snd_nxt);
1466 wmem = READ_ONCE(ssk->sk_wmem_queued);
1467 if (!burst)
1468 return ssk;
1469
1470 subflow = mptcp_subflow_ctx(ssk);
1471 subflow->avg_pacing_rate = div_u64((u64)subflow->avg_pacing_rate * wmem +
1472 READ_ONCE(ssk->sk_pacing_rate) * burst,
1473 burst + wmem);
1474 msk->snd_burst = burst;
1475 return ssk;
1476}
1477
1478static void mptcp_push_release(struct sock *ssk, struct mptcp_sendmsg_info *info)
1479{
1480 tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal);
1481 release_sock(ssk);
1482}
1483
1484static void mptcp_update_post_push(struct mptcp_sock *msk,
1485 struct mptcp_data_frag *dfrag,
1486 u32 sent)
1487{
1488 u64 snd_nxt_new = dfrag->data_seq;
1489
1490 dfrag->already_sent += sent;
1491
1492 msk->snd_burst -= sent;
1493
1494 snd_nxt_new += dfrag->already_sent;
1495
1496 /* snd_nxt_new can be smaller than snd_nxt in case mptcp
1497 * is recovering after a failover. In that event, this re-sends
1498 * old segments.
1499 *
1500 * Thus compute snd_nxt_new candidate based on
1501 * the dfrag->data_seq that was sent and the data
1502 * that has been handed to the subflow for transmission
1503 * and skip update in case it was old dfrag.
1504 */
1505 if (likely(after64(snd_nxt_new, msk->snd_nxt))) {
1506 msk->bytes_sent += snd_nxt_new - msk->snd_nxt;
1507 WRITE_ONCE(msk->snd_nxt, snd_nxt_new);
1508 }
1509}
1510
1511void mptcp_check_and_set_pending(struct sock *sk)
1512{
1513 if (mptcp_send_head(sk)) {
1514 mptcp_data_lock(sk);
1515 mptcp_sk(sk)->cb_flags |= BIT(MPTCP_PUSH_PENDING);
1516 mptcp_data_unlock(sk);
1517 }
1518}
1519
1520static int __subflow_push_pending(struct sock *sk, struct sock *ssk,
1521 struct mptcp_sendmsg_info *info)
1522{
1523 struct mptcp_sock *msk = mptcp_sk(sk);
1524 struct mptcp_data_frag *dfrag;
1525 int len, copied = 0, err = 0;
1526
1527 while ((dfrag = mptcp_send_head(sk))) {
1528 info->sent = dfrag->already_sent;
1529 info->limit = dfrag->data_len;
1530 len = dfrag->data_len - dfrag->already_sent;
1531 while (len > 0) {
1532 int ret = 0;
1533
1534 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, info);
1535 if (ret <= 0) {
1536 err = copied ? : ret;
1537 goto out;
1538 }
1539
1540 info->sent += ret;
1541 copied += ret;
1542 len -= ret;
1543
1544 mptcp_update_post_push(msk, dfrag, ret);
1545 }
1546 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1547
1548 if (msk->snd_burst <= 0 ||
1549 !sk_stream_memory_free(ssk) ||
1550 !mptcp_subflow_active(mptcp_subflow_ctx(ssk))) {
1551 err = copied;
1552 goto out;
1553 }
1554 mptcp_set_timeout(sk);
1555 }
1556 err = copied;
1557
1558out:
1559 return err;
1560}
1561
1562void __mptcp_push_pending(struct sock *sk, unsigned int flags)
1563{
1564 struct sock *prev_ssk = NULL, *ssk = NULL;
1565 struct mptcp_sock *msk = mptcp_sk(sk);
1566 struct mptcp_sendmsg_info info = {
1567 .flags = flags,
1568 };
1569 bool do_check_data_fin = false;
1570 int push_count = 1;
1571
1572 while (mptcp_send_head(sk) && (push_count > 0)) {
1573 struct mptcp_subflow_context *subflow;
1574 int ret = 0;
1575
1576 if (mptcp_sched_get_send(msk))
1577 break;
1578
1579 push_count = 0;
1580
1581 mptcp_for_each_subflow(msk, subflow) {
1582 if (READ_ONCE(subflow->scheduled)) {
1583 mptcp_subflow_set_scheduled(subflow, false);
1584
1585 prev_ssk = ssk;
1586 ssk = mptcp_subflow_tcp_sock(subflow);
1587 if (ssk != prev_ssk) {
1588 /* First check. If the ssk has changed since
1589 * the last round, release prev_ssk
1590 */
1591 if (prev_ssk)
1592 mptcp_push_release(prev_ssk, &info);
1593
1594 /* Need to lock the new subflow only if different
1595 * from the previous one, otherwise we are still
1596 * helding the relevant lock
1597 */
1598 lock_sock(ssk);
1599 }
1600
1601 push_count++;
1602
1603 ret = __subflow_push_pending(sk, ssk, &info);
1604 if (ret <= 0) {
1605 if (ret != -EAGAIN ||
1606 (1 << ssk->sk_state) &
1607 (TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSE))
1608 push_count--;
1609 continue;
1610 }
1611 do_check_data_fin = true;
1612 }
1613 }
1614 }
1615
1616 /* at this point we held the socket lock for the last subflow we used */
1617 if (ssk)
1618 mptcp_push_release(ssk, &info);
1619
1620 /* ensure the rtx timer is running */
1621 if (!mptcp_rtx_timer_pending(sk))
1622 mptcp_reset_rtx_timer(sk);
1623 if (do_check_data_fin)
1624 mptcp_check_send_data_fin(sk);
1625}
1626
1627static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk, bool first)
1628{
1629 struct mptcp_sock *msk = mptcp_sk(sk);
1630 struct mptcp_sendmsg_info info = {
1631 .data_lock_held = true,
1632 };
1633 bool keep_pushing = true;
1634 struct sock *xmit_ssk;
1635 int copied = 0;
1636
1637 info.flags = 0;
1638 while (mptcp_send_head(sk) && keep_pushing) {
1639 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1640 int ret = 0;
1641
1642 /* check for a different subflow usage only after
1643 * spooling the first chunk of data
1644 */
1645 if (first) {
1646 mptcp_subflow_set_scheduled(subflow, false);
1647 ret = __subflow_push_pending(sk, ssk, &info);
1648 first = false;
1649 if (ret <= 0)
1650 break;
1651 copied += ret;
1652 continue;
1653 }
1654
1655 if (mptcp_sched_get_send(msk))
1656 goto out;
1657
1658 if (READ_ONCE(subflow->scheduled)) {
1659 mptcp_subflow_set_scheduled(subflow, false);
1660 ret = __subflow_push_pending(sk, ssk, &info);
1661 if (ret <= 0)
1662 keep_pushing = false;
1663 copied += ret;
1664 }
1665
1666 mptcp_for_each_subflow(msk, subflow) {
1667 if (READ_ONCE(subflow->scheduled)) {
1668 xmit_ssk = mptcp_subflow_tcp_sock(subflow);
1669 if (xmit_ssk != ssk) {
1670 mptcp_subflow_delegate(subflow,
1671 MPTCP_DELEGATE_SEND);
1672 keep_pushing = false;
1673 }
1674 }
1675 }
1676 }
1677
1678out:
1679 /* __mptcp_alloc_tx_skb could have released some wmem and we are
1680 * not going to flush it via release_sock()
1681 */
1682 if (copied) {
1683 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
1684 info.size_goal);
1685 if (!mptcp_rtx_timer_pending(sk))
1686 mptcp_reset_rtx_timer(sk);
1687
1688 if (msk->snd_data_fin_enable &&
1689 msk->snd_nxt + 1 == msk->write_seq)
1690 mptcp_schedule_work(sk);
1691 }
1692}
1693
1694static int mptcp_disconnect(struct sock *sk, int flags);
1695
1696static int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
1697 size_t len, int *copied_syn)
1698{
1699 unsigned int saved_flags = msg->msg_flags;
1700 struct mptcp_sock *msk = mptcp_sk(sk);
1701 struct sock *ssk;
1702 int ret;
1703
1704 /* on flags based fastopen the mptcp is supposed to create the
1705 * first subflow right now. Otherwise we are in the defer_connect
1706 * path, and the first subflow must be already present.
1707 * Since the defer_connect flag is cleared after the first succsful
1708 * fastopen attempt, no need to check for additional subflow status.
1709 */
1710 if (msg->msg_flags & MSG_FASTOPEN) {
1711 ssk = __mptcp_nmpc_sk(msk);
1712 if (IS_ERR(ssk))
1713 return PTR_ERR(ssk);
1714 }
1715 if (!msk->first)
1716 return -EINVAL;
1717
1718 ssk = msk->first;
1719
1720 lock_sock(ssk);
1721 msg->msg_flags |= MSG_DONTWAIT;
1722 msk->fastopening = 1;
1723 ret = tcp_sendmsg_fastopen(ssk, msg, copied_syn, len, NULL);
1724 msk->fastopening = 0;
1725 msg->msg_flags = saved_flags;
1726 release_sock(ssk);
1727
1728 /* do the blocking bits of inet_stream_connect outside the ssk socket lock */
1729 if (ret == -EINPROGRESS && !(msg->msg_flags & MSG_DONTWAIT)) {
1730 ret = __inet_stream_connect(sk->sk_socket, msg->msg_name,
1731 msg->msg_namelen, msg->msg_flags, 1);
1732
1733 /* Keep the same behaviour of plain TCP: zero the copied bytes in
1734 * case of any error, except timeout or signal
1735 */
1736 if (ret && ret != -EINPROGRESS && ret != -ERESTARTSYS && ret != -EINTR)
1737 *copied_syn = 0;
1738 } else if (ret && ret != -EINPROGRESS) {
1739 /* The disconnect() op called by tcp_sendmsg_fastopen()/
1740 * __inet_stream_connect() can fail, due to looking check,
1741 * see mptcp_disconnect().
1742 * Attempt it again outside the problematic scope.
1743 */
1744 if (!mptcp_disconnect(sk, 0))
1745 sk->sk_socket->state = SS_UNCONNECTED;
1746 }
1747 inet_clear_bit(DEFER_CONNECT, sk);
1748
1749 return ret;
1750}
1751
1752static int do_copy_data_nocache(struct sock *sk, int copy,
1753 struct iov_iter *from, char *to)
1754{
1755 if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) {
1756 if (!copy_from_iter_full_nocache(to, copy, from))
1757 return -EFAULT;
1758 } else if (!copy_from_iter_full(to, copy, from)) {
1759 return -EFAULT;
1760 }
1761 return 0;
1762}
1763
1764/* open-code sk_stream_memory_free() plus sent limit computation to
1765 * avoid indirect calls in fast-path.
1766 * Called under the msk socket lock, so we can avoid a bunch of ONCE
1767 * annotations.
1768 */
1769static u32 mptcp_send_limit(const struct sock *sk)
1770{
1771 const struct mptcp_sock *msk = mptcp_sk(sk);
1772 u32 limit, not_sent;
1773
1774 if (sk->sk_wmem_queued >= READ_ONCE(sk->sk_sndbuf))
1775 return 0;
1776
1777 limit = mptcp_notsent_lowat(sk);
1778 if (limit == UINT_MAX)
1779 return UINT_MAX;
1780
1781 not_sent = msk->write_seq - msk->snd_nxt;
1782 if (not_sent >= limit)
1783 return 0;
1784
1785 return limit - not_sent;
1786}
1787
1788static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
1789{
1790 struct mptcp_sock *msk = mptcp_sk(sk);
1791 struct page_frag *pfrag;
1792 size_t copied = 0;
1793 int ret = 0;
1794 long timeo;
1795
1796 /* silently ignore everything else */
1797 msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | MSG_FASTOPEN;
1798
1799 lock_sock(sk);
1800
1801 if (unlikely(inet_test_bit(DEFER_CONNECT, sk) ||
1802 msg->msg_flags & MSG_FASTOPEN)) {
1803 int copied_syn = 0;
1804
1805 ret = mptcp_sendmsg_fastopen(sk, msg, len, &copied_syn);
1806 copied += copied_syn;
1807 if (ret == -EINPROGRESS && copied_syn > 0)
1808 goto out;
1809 else if (ret)
1810 goto do_error;
1811 }
1812
1813 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1814
1815 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
1816 ret = sk_stream_wait_connect(sk, &timeo);
1817 if (ret)
1818 goto do_error;
1819 }
1820
1821 ret = -EPIPE;
1822 if (unlikely(sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)))
1823 goto do_error;
1824
1825 pfrag = sk_page_frag(sk);
1826
1827 while (msg_data_left(msg)) {
1828 int total_ts, frag_truesize = 0;
1829 struct mptcp_data_frag *dfrag;
1830 bool dfrag_collapsed;
1831 size_t psize, offset;
1832 u32 copy_limit;
1833
1834 /* ensure fitting the notsent_lowat() constraint */
1835 copy_limit = mptcp_send_limit(sk);
1836 if (!copy_limit)
1837 goto wait_for_memory;
1838
1839 /* reuse tail pfrag, if possible, or carve a new one from the
1840 * page allocator
1841 */
1842 dfrag = mptcp_pending_tail(sk);
1843 dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag);
1844 if (!dfrag_collapsed) {
1845 if (!mptcp_page_frag_refill(sk, pfrag))
1846 goto wait_for_memory;
1847
1848 dfrag = mptcp_carve_data_frag(msk, pfrag, pfrag->offset);
1849 frag_truesize = dfrag->overhead;
1850 }
1851
1852 /* we do not bound vs wspace, to allow a single packet.
1853 * memory accounting will prevent execessive memory usage
1854 * anyway
1855 */
1856 offset = dfrag->offset + dfrag->data_len;
1857 psize = pfrag->size - offset;
1858 psize = min_t(size_t, psize, msg_data_left(msg));
1859 psize = min_t(size_t, psize, copy_limit);
1860 total_ts = psize + frag_truesize;
1861
1862 if (!sk_wmem_schedule(sk, total_ts))
1863 goto wait_for_memory;
1864
1865 ret = do_copy_data_nocache(sk, psize, &msg->msg_iter,
1866 page_address(dfrag->page) + offset);
1867 if (ret)
1868 goto do_error;
1869
1870 /* data successfully copied into the write queue */
1871 sk_forward_alloc_add(sk, -total_ts);
1872 copied += psize;
1873 dfrag->data_len += psize;
1874 frag_truesize += psize;
1875 pfrag->offset += frag_truesize;
1876 WRITE_ONCE(msk->write_seq, msk->write_seq + psize);
1877
1878 /* charge data on mptcp pending queue to the msk socket
1879 * Note: we charge such data both to sk and ssk
1880 */
1881 sk_wmem_queued_add(sk, frag_truesize);
1882 if (!dfrag_collapsed) {
1883 get_page(dfrag->page);
1884 list_add_tail(&dfrag->list, &msk->rtx_queue);
1885 if (!msk->first_pending)
1886 WRITE_ONCE(msk->first_pending, dfrag);
1887 }
1888 pr_debug("msk=%p dfrag at seq=%llu len=%u sent=%u new=%d", msk,
1889 dfrag->data_seq, dfrag->data_len, dfrag->already_sent,
1890 !dfrag_collapsed);
1891
1892 continue;
1893
1894wait_for_memory:
1895 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1896 __mptcp_push_pending(sk, msg->msg_flags);
1897 ret = sk_stream_wait_memory(sk, &timeo);
1898 if (ret)
1899 goto do_error;
1900 }
1901
1902 if (copied)
1903 __mptcp_push_pending(sk, msg->msg_flags);
1904
1905out:
1906 release_sock(sk);
1907 return copied;
1908
1909do_error:
1910 if (copied)
1911 goto out;
1912
1913 copied = sk_stream_error(sk, msg->msg_flags, ret);
1914 goto out;
1915}
1916
1917static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk,
1918 struct msghdr *msg,
1919 size_t len, int flags,
1920 struct scm_timestamping_internal *tss,
1921 int *cmsg_flags)
1922{
1923 struct sk_buff *skb, *tmp;
1924 int copied = 0;
1925
1926 skb_queue_walk_safe(&msk->receive_queue, skb, tmp) {
1927 u32 offset = MPTCP_SKB_CB(skb)->offset;
1928 u32 data_len = skb->len - offset;
1929 u32 count = min_t(size_t, len - copied, data_len);
1930 int err;
1931
1932 if (!(flags & MSG_TRUNC)) {
1933 err = skb_copy_datagram_msg(skb, offset, msg, count);
1934 if (unlikely(err < 0)) {
1935 if (!copied)
1936 return err;
1937 break;
1938 }
1939 }
1940
1941 if (MPTCP_SKB_CB(skb)->has_rxtstamp) {
1942 tcp_update_recv_tstamps(skb, tss);
1943 *cmsg_flags |= MPTCP_CMSG_TS;
1944 }
1945
1946 copied += count;
1947
1948 if (count < data_len) {
1949 if (!(flags & MSG_PEEK)) {
1950 MPTCP_SKB_CB(skb)->offset += count;
1951 MPTCP_SKB_CB(skb)->map_seq += count;
1952 msk->bytes_consumed += count;
1953 }
1954 break;
1955 }
1956
1957 if (!(flags & MSG_PEEK)) {
1958 /* we will bulk release the skb memory later */
1959 skb->destructor = NULL;
1960 WRITE_ONCE(msk->rmem_released, msk->rmem_released + skb->truesize);
1961 __skb_unlink(skb, &msk->receive_queue);
1962 __kfree_skb(skb);
1963 msk->bytes_consumed += count;
1964 }
1965
1966 if (copied >= len)
1967 break;
1968 }
1969
1970 return copied;
1971}
1972
1973/* receive buffer autotuning. See tcp_rcv_space_adjust for more information.
1974 *
1975 * Only difference: Use highest rtt estimate of the subflows in use.
1976 */
1977static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied)
1978{
1979 struct mptcp_subflow_context *subflow;
1980 struct sock *sk = (struct sock *)msk;
1981 u8 scaling_ratio = U8_MAX;
1982 u32 time, advmss = 1;
1983 u64 rtt_us, mstamp;
1984
1985 msk_owned_by_me(msk);
1986
1987 if (copied <= 0)
1988 return;
1989
1990 if (!msk->rcvspace_init)
1991 mptcp_rcv_space_init(msk, msk->first);
1992
1993 msk->rcvq_space.copied += copied;
1994
1995 mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC);
1996 time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time);
1997
1998 rtt_us = msk->rcvq_space.rtt_us;
1999 if (rtt_us && time < (rtt_us >> 3))
2000 return;
2001
2002 rtt_us = 0;
2003 mptcp_for_each_subflow(msk, subflow) {
2004 const struct tcp_sock *tp;
2005 u64 sf_rtt_us;
2006 u32 sf_advmss;
2007
2008 tp = tcp_sk(mptcp_subflow_tcp_sock(subflow));
2009
2010 sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us);
2011 sf_advmss = READ_ONCE(tp->advmss);
2012
2013 rtt_us = max(sf_rtt_us, rtt_us);
2014 advmss = max(sf_advmss, advmss);
2015 scaling_ratio = min(tp->scaling_ratio, scaling_ratio);
2016 }
2017
2018 msk->rcvq_space.rtt_us = rtt_us;
2019 msk->scaling_ratio = scaling_ratio;
2020 if (time < (rtt_us >> 3) || rtt_us == 0)
2021 return;
2022
2023 if (msk->rcvq_space.copied <= msk->rcvq_space.space)
2024 goto new_measure;
2025
2026 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf) &&
2027 !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
2028 u64 rcvwin, grow;
2029 int rcvbuf;
2030
2031 rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss;
2032
2033 grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space);
2034
2035 do_div(grow, msk->rcvq_space.space);
2036 rcvwin += (grow << 1);
2037
2038 rcvbuf = min_t(u64, __tcp_space_from_win(scaling_ratio, rcvwin),
2039 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[2]));
2040
2041 if (rcvbuf > sk->sk_rcvbuf) {
2042 u32 window_clamp;
2043
2044 window_clamp = __tcp_win_from_space(scaling_ratio, rcvbuf);
2045 WRITE_ONCE(sk->sk_rcvbuf, rcvbuf);
2046
2047 /* Make subflows follow along. If we do not do this, we
2048 * get drops at subflow level if skbs can't be moved to
2049 * the mptcp rx queue fast enough (announced rcv_win can
2050 * exceed ssk->sk_rcvbuf).
2051 */
2052 mptcp_for_each_subflow(msk, subflow) {
2053 struct sock *ssk;
2054 bool slow;
2055
2056 ssk = mptcp_subflow_tcp_sock(subflow);
2057 slow = lock_sock_fast(ssk);
2058 WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf);
2059 tcp_sk(ssk)->window_clamp = window_clamp;
2060 tcp_cleanup_rbuf(ssk, 1);
2061 unlock_sock_fast(ssk, slow);
2062 }
2063 }
2064 }
2065
2066 msk->rcvq_space.space = msk->rcvq_space.copied;
2067new_measure:
2068 msk->rcvq_space.copied = 0;
2069 msk->rcvq_space.time = mstamp;
2070}
2071
2072static void __mptcp_update_rmem(struct sock *sk)
2073{
2074 struct mptcp_sock *msk = mptcp_sk(sk);
2075
2076 if (!msk->rmem_released)
2077 return;
2078
2079 atomic_sub(msk->rmem_released, &sk->sk_rmem_alloc);
2080 mptcp_rmem_uncharge(sk, msk->rmem_released);
2081 WRITE_ONCE(msk->rmem_released, 0);
2082}
2083
2084static void __mptcp_splice_receive_queue(struct sock *sk)
2085{
2086 struct mptcp_sock *msk = mptcp_sk(sk);
2087
2088 skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue);
2089}
2090
2091static bool __mptcp_move_skbs(struct mptcp_sock *msk)
2092{
2093 struct sock *sk = (struct sock *)msk;
2094 unsigned int moved = 0;
2095 bool ret, done;
2096
2097 do {
2098 struct sock *ssk = mptcp_subflow_recv_lookup(msk);
2099 bool slowpath;
2100
2101 /* we can have data pending in the subflows only if the msk
2102 * receive buffer was full at subflow_data_ready() time,
2103 * that is an unlikely slow path.
2104 */
2105 if (likely(!ssk))
2106 break;
2107
2108 slowpath = lock_sock_fast(ssk);
2109 mptcp_data_lock(sk);
2110 __mptcp_update_rmem(sk);
2111 done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
2112 mptcp_data_unlock(sk);
2113
2114 if (unlikely(ssk->sk_err))
2115 __mptcp_error_report(sk);
2116 unlock_sock_fast(ssk, slowpath);
2117 } while (!done);
2118
2119 /* acquire the data lock only if some input data is pending */
2120 ret = moved > 0;
2121 if (!RB_EMPTY_ROOT(&msk->out_of_order_queue) ||
2122 !skb_queue_empty_lockless(&sk->sk_receive_queue)) {
2123 mptcp_data_lock(sk);
2124 __mptcp_update_rmem(sk);
2125 ret |= __mptcp_ofo_queue(msk);
2126 __mptcp_splice_receive_queue(sk);
2127 mptcp_data_unlock(sk);
2128 }
2129 if (ret)
2130 mptcp_check_data_fin((struct sock *)msk);
2131 return !skb_queue_empty(&msk->receive_queue);
2132}
2133
2134static unsigned int mptcp_inq_hint(const struct sock *sk)
2135{
2136 const struct mptcp_sock *msk = mptcp_sk(sk);
2137 const struct sk_buff *skb;
2138
2139 skb = skb_peek(&msk->receive_queue);
2140 if (skb) {
2141 u64 hint_val = READ_ONCE(msk->ack_seq) - MPTCP_SKB_CB(skb)->map_seq;
2142
2143 if (hint_val >= INT_MAX)
2144 return INT_MAX;
2145
2146 return (unsigned int)hint_val;
2147 }
2148
2149 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
2150 return 1;
2151
2152 return 0;
2153}
2154
2155static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
2156 int flags, int *addr_len)
2157{
2158 struct mptcp_sock *msk = mptcp_sk(sk);
2159 struct scm_timestamping_internal tss;
2160 int copied = 0, cmsg_flags = 0;
2161 int target;
2162 long timeo;
2163
2164 /* MSG_ERRQUEUE is really a no-op till we support IP_RECVERR */
2165 if (unlikely(flags & MSG_ERRQUEUE))
2166 return inet_recv_error(sk, msg, len, addr_len);
2167
2168 lock_sock(sk);
2169 if (unlikely(sk->sk_state == TCP_LISTEN)) {
2170 copied = -ENOTCONN;
2171 goto out_err;
2172 }
2173
2174 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2175
2176 len = min_t(size_t, len, INT_MAX);
2177 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
2178
2179 if (unlikely(msk->recvmsg_inq))
2180 cmsg_flags = MPTCP_CMSG_INQ;
2181
2182 while (copied < len) {
2183 int bytes_read;
2184
2185 bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags, &tss, &cmsg_flags);
2186 if (unlikely(bytes_read < 0)) {
2187 if (!copied)
2188 copied = bytes_read;
2189 goto out_err;
2190 }
2191
2192 copied += bytes_read;
2193
2194 /* be sure to advertise window change */
2195 mptcp_cleanup_rbuf(msk);
2196
2197 if (skb_queue_empty(&msk->receive_queue) && __mptcp_move_skbs(msk))
2198 continue;
2199
2200 /* only the master socket status is relevant here. The exit
2201 * conditions mirror closely tcp_recvmsg()
2202 */
2203 if (copied >= target)
2204 break;
2205
2206 if (copied) {
2207 if (sk->sk_err ||
2208 sk->sk_state == TCP_CLOSE ||
2209 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2210 !timeo ||
2211 signal_pending(current))
2212 break;
2213 } else {
2214 if (sk->sk_err) {
2215 copied = sock_error(sk);
2216 break;
2217 }
2218
2219 if (sk->sk_shutdown & RCV_SHUTDOWN) {
2220 /* race breaker: the shutdown could be after the
2221 * previous receive queue check
2222 */
2223 if (__mptcp_move_skbs(msk))
2224 continue;
2225 break;
2226 }
2227
2228 if (sk->sk_state == TCP_CLOSE) {
2229 copied = -ENOTCONN;
2230 break;
2231 }
2232
2233 if (!timeo) {
2234 copied = -EAGAIN;
2235 break;
2236 }
2237
2238 if (signal_pending(current)) {
2239 copied = sock_intr_errno(timeo);
2240 break;
2241 }
2242 }
2243
2244 pr_debug("block timeout %ld", timeo);
2245 sk_wait_data(sk, &timeo, NULL);
2246 }
2247
2248out_err:
2249 if (cmsg_flags && copied >= 0) {
2250 if (cmsg_flags & MPTCP_CMSG_TS)
2251 tcp_recv_timestamp(msg, sk, &tss);
2252
2253 if (cmsg_flags & MPTCP_CMSG_INQ) {
2254 unsigned int inq = mptcp_inq_hint(sk);
2255
2256 put_cmsg(msg, SOL_TCP, TCP_CM_INQ, sizeof(inq), &inq);
2257 }
2258 }
2259
2260 pr_debug("msk=%p rx queue empty=%d:%d copied=%d",
2261 msk, skb_queue_empty_lockless(&sk->sk_receive_queue),
2262 skb_queue_empty(&msk->receive_queue), copied);
2263 if (!(flags & MSG_PEEK))
2264 mptcp_rcv_space_adjust(msk, copied);
2265
2266 release_sock(sk);
2267 return copied;
2268}
2269
2270static void mptcp_retransmit_timer(struct timer_list *t)
2271{
2272 struct inet_connection_sock *icsk = from_timer(icsk, t,
2273 icsk_retransmit_timer);
2274 struct sock *sk = &icsk->icsk_inet.sk;
2275 struct mptcp_sock *msk = mptcp_sk(sk);
2276
2277 bh_lock_sock(sk);
2278 if (!sock_owned_by_user(sk)) {
2279 /* we need a process context to retransmit */
2280 if (!test_and_set_bit(MPTCP_WORK_RTX, &msk->flags))
2281 mptcp_schedule_work(sk);
2282 } else {
2283 /* delegate our work to tcp_release_cb() */
2284 __set_bit(MPTCP_RETRANSMIT, &msk->cb_flags);
2285 }
2286 bh_unlock_sock(sk);
2287 sock_put(sk);
2288}
2289
2290static void mptcp_tout_timer(struct timer_list *t)
2291{
2292 struct sock *sk = from_timer(sk, t, sk_timer);
2293
2294 mptcp_schedule_work(sk);
2295 sock_put(sk);
2296}
2297
2298/* Find an idle subflow. Return NULL if there is unacked data at tcp
2299 * level.
2300 *
2301 * A backup subflow is returned only if that is the only kind available.
2302 */
2303struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk)
2304{
2305 struct sock *backup = NULL, *pick = NULL;
2306 struct mptcp_subflow_context *subflow;
2307 int min_stale_count = INT_MAX;
2308
2309 mptcp_for_each_subflow(msk, subflow) {
2310 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2311
2312 if (!__mptcp_subflow_active(subflow))
2313 continue;
2314
2315 /* still data outstanding at TCP level? skip this */
2316 if (!tcp_rtx_and_write_queues_empty(ssk)) {
2317 mptcp_pm_subflow_chk_stale(msk, ssk);
2318 min_stale_count = min_t(int, min_stale_count, subflow->stale_count);
2319 continue;
2320 }
2321
2322 if (subflow->backup) {
2323 if (!backup)
2324 backup = ssk;
2325 continue;
2326 }
2327
2328 if (!pick)
2329 pick = ssk;
2330 }
2331
2332 if (pick)
2333 return pick;
2334
2335 /* use backup only if there are no progresses anywhere */
2336 return min_stale_count > 1 ? backup : NULL;
2337}
2338
2339bool __mptcp_retransmit_pending_data(struct sock *sk)
2340{
2341 struct mptcp_data_frag *cur, *rtx_head;
2342 struct mptcp_sock *msk = mptcp_sk(sk);
2343
2344 if (__mptcp_check_fallback(msk))
2345 return false;
2346
2347 /* the closing socket has some data untransmitted and/or unacked:
2348 * some data in the mptcp rtx queue has not really xmitted yet.
2349 * keep it simple and re-inject the whole mptcp level rtx queue
2350 */
2351 mptcp_data_lock(sk);
2352 __mptcp_clean_una_wakeup(sk);
2353 rtx_head = mptcp_rtx_head(sk);
2354 if (!rtx_head) {
2355 mptcp_data_unlock(sk);
2356 return false;
2357 }
2358
2359 msk->recovery_snd_nxt = msk->snd_nxt;
2360 msk->recovery = true;
2361 mptcp_data_unlock(sk);
2362
2363 msk->first_pending = rtx_head;
2364 msk->snd_burst = 0;
2365
2366 /* be sure to clear the "sent status" on all re-injected fragments */
2367 list_for_each_entry(cur, &msk->rtx_queue, list) {
2368 if (!cur->already_sent)
2369 break;
2370 cur->already_sent = 0;
2371 }
2372
2373 return true;
2374}
2375
2376/* flags for __mptcp_close_ssk() */
2377#define MPTCP_CF_PUSH BIT(1)
2378#define MPTCP_CF_FASTCLOSE BIT(2)
2379
2380/* be sure to send a reset only if the caller asked for it, also
2381 * clean completely the subflow status when the subflow reaches
2382 * TCP_CLOSE state
2383 */
2384static void __mptcp_subflow_disconnect(struct sock *ssk,
2385 struct mptcp_subflow_context *subflow,
2386 unsigned int flags)
2387{
2388 if (((1 << ssk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) ||
2389 (flags & MPTCP_CF_FASTCLOSE)) {
2390 /* The MPTCP code never wait on the subflow sockets, TCP-level
2391 * disconnect should never fail
2392 */
2393 WARN_ON_ONCE(tcp_disconnect(ssk, 0));
2394 mptcp_subflow_ctx_reset(subflow);
2395 } else {
2396 tcp_shutdown(ssk, SEND_SHUTDOWN);
2397 }
2398}
2399
2400/* subflow sockets can be either outgoing (connect) or incoming
2401 * (accept).
2402 *
2403 * Outgoing subflows use in-kernel sockets.
2404 * Incoming subflows do not have their own 'struct socket' allocated,
2405 * so we need to use tcp_close() after detaching them from the mptcp
2406 * parent socket.
2407 */
2408static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
2409 struct mptcp_subflow_context *subflow,
2410 unsigned int flags)
2411{
2412 struct mptcp_sock *msk = mptcp_sk(sk);
2413 bool dispose_it, need_push = false;
2414
2415 /* If the first subflow moved to a close state before accept, e.g. due
2416 * to an incoming reset or listener shutdown, the subflow socket is
2417 * already deleted by inet_child_forget() and the mptcp socket can't
2418 * survive too.
2419 */
2420 if (msk->in_accept_queue && msk->first == ssk &&
2421 (sock_flag(sk, SOCK_DEAD) || sock_flag(ssk, SOCK_DEAD))) {
2422 /* ensure later check in mptcp_worker() will dispose the msk */
2423 sock_set_flag(sk, SOCK_DEAD);
2424 mptcp_set_close_tout(sk, tcp_jiffies32 - (mptcp_close_timeout(sk) + 1));
2425 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
2426 mptcp_subflow_drop_ctx(ssk);
2427 goto out_release;
2428 }
2429
2430 dispose_it = msk->free_first || ssk != msk->first;
2431 if (dispose_it)
2432 list_del(&subflow->node);
2433
2434 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
2435
2436 if ((flags & MPTCP_CF_FASTCLOSE) && !__mptcp_check_fallback(msk)) {
2437 /* be sure to force the tcp_close path
2438 * to generate the egress reset
2439 */
2440 ssk->sk_lingertime = 0;
2441 sock_set_flag(ssk, SOCK_LINGER);
2442 subflow->send_fastclose = 1;
2443 }
2444
2445 need_push = (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(sk);
2446 if (!dispose_it) {
2447 __mptcp_subflow_disconnect(ssk, subflow, flags);
2448 release_sock(ssk);
2449
2450 goto out;
2451 }
2452
2453 subflow->disposable = 1;
2454
2455 /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops
2456 * the ssk has been already destroyed, we just need to release the
2457 * reference owned by msk;
2458 */
2459 if (!inet_csk(ssk)->icsk_ulp_ops) {
2460 WARN_ON_ONCE(!sock_flag(ssk, SOCK_DEAD));
2461 kfree_rcu(subflow, rcu);
2462 } else {
2463 /* otherwise tcp will dispose of the ssk and subflow ctx */
2464 __tcp_close(ssk, 0);
2465
2466 /* close acquired an extra ref */
2467 __sock_put(ssk);
2468 }
2469
2470out_release:
2471 __mptcp_subflow_error_report(sk, ssk);
2472 release_sock(ssk);
2473
2474 sock_put(ssk);
2475
2476 if (ssk == msk->first)
2477 WRITE_ONCE(msk->first, NULL);
2478
2479out:
2480 __mptcp_sync_sndbuf(sk);
2481 if (need_push)
2482 __mptcp_push_pending(sk, 0);
2483
2484 /* Catch every 'all subflows closed' scenario, including peers silently
2485 * closing them, e.g. due to timeout.
2486 * For established sockets, allow an additional timeout before closing,
2487 * as the protocol can still create more subflows.
2488 */
2489 if (list_is_singular(&msk->conn_list) && msk->first &&
2490 inet_sk_state_load(msk->first) == TCP_CLOSE) {
2491 if (sk->sk_state != TCP_ESTABLISHED ||
2492 msk->in_accept_queue || sock_flag(sk, SOCK_DEAD)) {
2493 mptcp_set_state(sk, TCP_CLOSE);
2494 mptcp_close_wake_up(sk);
2495 } else {
2496 mptcp_start_tout_timer(sk);
2497 }
2498 }
2499}
2500
2501void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
2502 struct mptcp_subflow_context *subflow)
2503{
2504 if (sk->sk_state == TCP_ESTABLISHED)
2505 mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL);
2506
2507 /* subflow aborted before reaching the fully_established status
2508 * attempt the creation of the next subflow
2509 */
2510 mptcp_pm_subflow_check_next(mptcp_sk(sk), subflow);
2511
2512 __mptcp_close_ssk(sk, ssk, subflow, MPTCP_CF_PUSH);
2513}
2514
2515static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu)
2516{
2517 return 0;
2518}
2519
2520static void __mptcp_close_subflow(struct sock *sk)
2521{
2522 struct mptcp_subflow_context *subflow, *tmp;
2523 struct mptcp_sock *msk = mptcp_sk(sk);
2524
2525 might_sleep();
2526
2527 mptcp_for_each_subflow_safe(msk, subflow, tmp) {
2528 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2529
2530 if (inet_sk_state_load(ssk) != TCP_CLOSE)
2531 continue;
2532
2533 /* 'subflow_data_ready' will re-sched once rx queue is empty */
2534 if (!skb_queue_empty_lockless(&ssk->sk_receive_queue))
2535 continue;
2536
2537 mptcp_close_ssk(sk, ssk, subflow);
2538 }
2539
2540}
2541
2542static bool mptcp_close_tout_expired(const struct sock *sk)
2543{
2544 if (!inet_csk(sk)->icsk_mtup.probe_timestamp ||
2545 sk->sk_state == TCP_CLOSE)
2546 return false;
2547
2548 return time_after32(tcp_jiffies32,
2549 inet_csk(sk)->icsk_mtup.probe_timestamp + mptcp_close_timeout(sk));
2550}
2551
2552static void mptcp_check_fastclose(struct mptcp_sock *msk)
2553{
2554 struct mptcp_subflow_context *subflow, *tmp;
2555 struct sock *sk = (struct sock *)msk;
2556
2557 if (likely(!READ_ONCE(msk->rcv_fastclose)))
2558 return;
2559
2560 mptcp_token_destroy(msk);
2561
2562 mptcp_for_each_subflow_safe(msk, subflow, tmp) {
2563 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
2564 bool slow;
2565
2566 slow = lock_sock_fast(tcp_sk);
2567 if (tcp_sk->sk_state != TCP_CLOSE) {
2568 tcp_send_active_reset(tcp_sk, GFP_ATOMIC);
2569 tcp_set_state(tcp_sk, TCP_CLOSE);
2570 }
2571 unlock_sock_fast(tcp_sk, slow);
2572 }
2573
2574 /* Mirror the tcp_reset() error propagation */
2575 switch (sk->sk_state) {
2576 case TCP_SYN_SENT:
2577 WRITE_ONCE(sk->sk_err, ECONNREFUSED);
2578 break;
2579 case TCP_CLOSE_WAIT:
2580 WRITE_ONCE(sk->sk_err, EPIPE);
2581 break;
2582 case TCP_CLOSE:
2583 return;
2584 default:
2585 WRITE_ONCE(sk->sk_err, ECONNRESET);
2586 }
2587
2588 mptcp_set_state(sk, TCP_CLOSE);
2589 WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
2590 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
2591 set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags);
2592
2593 /* the calling mptcp_worker will properly destroy the socket */
2594 if (sock_flag(sk, SOCK_DEAD))
2595 return;
2596
2597 sk->sk_state_change(sk);
2598 sk_error_report(sk);
2599}
2600
2601static void __mptcp_retrans(struct sock *sk)
2602{
2603 struct mptcp_sock *msk = mptcp_sk(sk);
2604 struct mptcp_subflow_context *subflow;
2605 struct mptcp_sendmsg_info info = {};
2606 struct mptcp_data_frag *dfrag;
2607 struct sock *ssk;
2608 int ret, err;
2609 u16 len = 0;
2610
2611 mptcp_clean_una_wakeup(sk);
2612
2613 /* first check ssk: need to kick "stale" logic */
2614 err = mptcp_sched_get_retrans(msk);
2615 dfrag = mptcp_rtx_head(sk);
2616 if (!dfrag) {
2617 if (mptcp_data_fin_enabled(msk)) {
2618 struct inet_connection_sock *icsk = inet_csk(sk);
2619
2620 icsk->icsk_retransmits++;
2621 mptcp_set_datafin_timeout(sk);
2622 mptcp_send_ack(msk);
2623
2624 goto reset_timer;
2625 }
2626
2627 if (!mptcp_send_head(sk))
2628 return;
2629
2630 goto reset_timer;
2631 }
2632
2633 if (err)
2634 goto reset_timer;
2635
2636 mptcp_for_each_subflow(msk, subflow) {
2637 if (READ_ONCE(subflow->scheduled)) {
2638 u16 copied = 0;
2639
2640 mptcp_subflow_set_scheduled(subflow, false);
2641
2642 ssk = mptcp_subflow_tcp_sock(subflow);
2643
2644 lock_sock(ssk);
2645
2646 /* limit retransmission to the bytes already sent on some subflows */
2647 info.sent = 0;
2648 info.limit = READ_ONCE(msk->csum_enabled) ? dfrag->data_len :
2649 dfrag->already_sent;
2650 while (info.sent < info.limit) {
2651 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
2652 if (ret <= 0)
2653 break;
2654
2655 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS);
2656 copied += ret;
2657 info.sent += ret;
2658 }
2659 if (copied) {
2660 len = max(copied, len);
2661 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
2662 info.size_goal);
2663 WRITE_ONCE(msk->allow_infinite_fallback, false);
2664 }
2665
2666 release_sock(ssk);
2667 }
2668 }
2669
2670 msk->bytes_retrans += len;
2671 dfrag->already_sent = max(dfrag->already_sent, len);
2672
2673reset_timer:
2674 mptcp_check_and_set_pending(sk);
2675
2676 if (!mptcp_rtx_timer_pending(sk))
2677 mptcp_reset_rtx_timer(sk);
2678}
2679
2680/* schedule the timeout timer for the relevant event: either close timeout
2681 * or mp_fail timeout. The close timeout takes precedence on the mp_fail one
2682 */
2683void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout)
2684{
2685 struct sock *sk = (struct sock *)msk;
2686 unsigned long timeout, close_timeout;
2687
2688 if (!fail_tout && !inet_csk(sk)->icsk_mtup.probe_timestamp)
2689 return;
2690
2691 close_timeout = inet_csk(sk)->icsk_mtup.probe_timestamp - tcp_jiffies32 + jiffies +
2692 mptcp_close_timeout(sk);
2693
2694 /* the close timeout takes precedence on the fail one, and here at least one of
2695 * them is active
2696 */
2697 timeout = inet_csk(sk)->icsk_mtup.probe_timestamp ? close_timeout : fail_tout;
2698
2699 sk_reset_timer(sk, &sk->sk_timer, timeout);
2700}
2701
2702static void mptcp_mp_fail_no_response(struct mptcp_sock *msk)
2703{
2704 struct sock *ssk = msk->first;
2705 bool slow;
2706
2707 if (!ssk)
2708 return;
2709
2710 pr_debug("MP_FAIL doesn't respond, reset the subflow");
2711
2712 slow = lock_sock_fast(ssk);
2713 mptcp_subflow_reset(ssk);
2714 WRITE_ONCE(mptcp_subflow_ctx(ssk)->fail_tout, 0);
2715 unlock_sock_fast(ssk, slow);
2716}
2717
2718static void mptcp_do_fastclose(struct sock *sk)
2719{
2720 struct mptcp_subflow_context *subflow, *tmp;
2721 struct mptcp_sock *msk = mptcp_sk(sk);
2722
2723 mptcp_set_state(sk, TCP_CLOSE);
2724 mptcp_for_each_subflow_safe(msk, subflow, tmp)
2725 __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow),
2726 subflow, MPTCP_CF_FASTCLOSE);
2727}
2728
2729static void mptcp_worker(struct work_struct *work)
2730{
2731 struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
2732 struct sock *sk = (struct sock *)msk;
2733 unsigned long fail_tout;
2734 int state;
2735
2736 lock_sock(sk);
2737 state = sk->sk_state;
2738 if (unlikely((1 << state) & (TCPF_CLOSE | TCPF_LISTEN)))
2739 goto unlock;
2740
2741 mptcp_check_fastclose(msk);
2742
2743 mptcp_pm_nl_work(msk);
2744
2745 mptcp_check_send_data_fin(sk);
2746 mptcp_check_data_fin_ack(sk);
2747 mptcp_check_data_fin(sk);
2748
2749 if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
2750 __mptcp_close_subflow(sk);
2751
2752 if (mptcp_close_tout_expired(sk)) {
2753 mptcp_do_fastclose(sk);
2754 mptcp_close_wake_up(sk);
2755 }
2756
2757 if (sock_flag(sk, SOCK_DEAD) && sk->sk_state == TCP_CLOSE) {
2758 __mptcp_destroy_sock(sk);
2759 goto unlock;
2760 }
2761
2762 if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
2763 __mptcp_retrans(sk);
2764
2765 fail_tout = msk->first ? READ_ONCE(mptcp_subflow_ctx(msk->first)->fail_tout) : 0;
2766 if (fail_tout && time_after(jiffies, fail_tout))
2767 mptcp_mp_fail_no_response(msk);
2768
2769unlock:
2770 release_sock(sk);
2771 sock_put(sk);
2772}
2773
2774static void __mptcp_init_sock(struct sock *sk)
2775{
2776 struct mptcp_sock *msk = mptcp_sk(sk);
2777
2778 INIT_LIST_HEAD(&msk->conn_list);
2779 INIT_LIST_HEAD(&msk->join_list);
2780 INIT_LIST_HEAD(&msk->rtx_queue);
2781 INIT_WORK(&msk->work, mptcp_worker);
2782 __skb_queue_head_init(&msk->receive_queue);
2783 msk->out_of_order_queue = RB_ROOT;
2784 msk->first_pending = NULL;
2785 WRITE_ONCE(msk->rmem_fwd_alloc, 0);
2786 WRITE_ONCE(msk->rmem_released, 0);
2787 msk->timer_ival = TCP_RTO_MIN;
2788 msk->scaling_ratio = TCP_DEFAULT_SCALING_RATIO;
2789
2790 WRITE_ONCE(msk->first, NULL);
2791 inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss;
2792 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
2793 WRITE_ONCE(msk->allow_infinite_fallback, true);
2794 msk->recovery = false;
2795 msk->subflow_id = 1;
2796
2797 mptcp_pm_data_init(msk);
2798
2799 /* re-use the csk retrans timer for MPTCP-level retrans */
2800 timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0);
2801 timer_setup(&sk->sk_timer, mptcp_tout_timer, 0);
2802}
2803
2804static void mptcp_ca_reset(struct sock *sk)
2805{
2806 struct inet_connection_sock *icsk = inet_csk(sk);
2807
2808 tcp_assign_congestion_control(sk);
2809 strcpy(mptcp_sk(sk)->ca_name, icsk->icsk_ca_ops->name);
2810
2811 /* no need to keep a reference to the ops, the name will suffice */
2812 tcp_cleanup_congestion_control(sk);
2813 icsk->icsk_ca_ops = NULL;
2814}
2815
2816static int mptcp_init_sock(struct sock *sk)
2817{
2818 struct net *net = sock_net(sk);
2819 int ret;
2820
2821 __mptcp_init_sock(sk);
2822
2823 if (!mptcp_is_enabled(net))
2824 return -ENOPROTOOPT;
2825
2826 if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net))
2827 return -ENOMEM;
2828
2829 ret = mptcp_init_sched(mptcp_sk(sk),
2830 mptcp_sched_find(mptcp_get_scheduler(net)));
2831 if (ret)
2832 return ret;
2833
2834 set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags);
2835
2836 /* fetch the ca name; do it outside __mptcp_init_sock(), so that clone will
2837 * propagate the correct value
2838 */
2839 mptcp_ca_reset(sk);
2840
2841 sk_sockets_allocated_inc(sk);
2842 sk->sk_rcvbuf = READ_ONCE(net->ipv4.sysctl_tcp_rmem[1]);
2843 sk->sk_sndbuf = READ_ONCE(net->ipv4.sysctl_tcp_wmem[1]);
2844
2845 return 0;
2846}
2847
2848static void __mptcp_clear_xmit(struct sock *sk)
2849{
2850 struct mptcp_sock *msk = mptcp_sk(sk);
2851 struct mptcp_data_frag *dtmp, *dfrag;
2852
2853 WRITE_ONCE(msk->first_pending, NULL);
2854 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list)
2855 dfrag_clear(sk, dfrag);
2856}
2857
2858void mptcp_cancel_work(struct sock *sk)
2859{
2860 struct mptcp_sock *msk = mptcp_sk(sk);
2861
2862 if (cancel_work_sync(&msk->work))
2863 __sock_put(sk);
2864}
2865
2866void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how)
2867{
2868 lock_sock(ssk);
2869
2870 switch (ssk->sk_state) {
2871 case TCP_LISTEN:
2872 if (!(how & RCV_SHUTDOWN))
2873 break;
2874 fallthrough;
2875 case TCP_SYN_SENT:
2876 WARN_ON_ONCE(tcp_disconnect(ssk, O_NONBLOCK));
2877 break;
2878 default:
2879 if (__mptcp_check_fallback(mptcp_sk(sk))) {
2880 pr_debug("Fallback");
2881 ssk->sk_shutdown |= how;
2882 tcp_shutdown(ssk, how);
2883
2884 /* simulate the data_fin ack reception to let the state
2885 * machine move forward
2886 */
2887 WRITE_ONCE(mptcp_sk(sk)->snd_una, mptcp_sk(sk)->snd_nxt);
2888 mptcp_schedule_work(sk);
2889 } else {
2890 pr_debug("Sending DATA_FIN on subflow %p", ssk);
2891 tcp_send_ack(ssk);
2892 if (!mptcp_rtx_timer_pending(sk))
2893 mptcp_reset_rtx_timer(sk);
2894 }
2895 break;
2896 }
2897
2898 release_sock(ssk);
2899}
2900
2901void mptcp_set_state(struct sock *sk, int state)
2902{
2903 int oldstate = sk->sk_state;
2904
2905 switch (state) {
2906 case TCP_ESTABLISHED:
2907 if (oldstate != TCP_ESTABLISHED)
2908 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_CURRESTAB);
2909 break;
2910
2911 default:
2912 if (oldstate == TCP_ESTABLISHED)
2913 MPTCP_DEC_STATS(sock_net(sk), MPTCP_MIB_CURRESTAB);
2914 }
2915
2916 inet_sk_state_store(sk, state);
2917}
2918
2919static const unsigned char new_state[16] = {
2920 /* current state: new state: action: */
2921 [0 /* (Invalid) */] = TCP_CLOSE,
2922 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2923 [TCP_SYN_SENT] = TCP_CLOSE,
2924 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2925 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1,
2926 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2,
2927 [TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */
2928 [TCP_CLOSE] = TCP_CLOSE,
2929 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN,
2930 [TCP_LAST_ACK] = TCP_LAST_ACK,
2931 [TCP_LISTEN] = TCP_CLOSE,
2932 [TCP_CLOSING] = TCP_CLOSING,
2933 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */
2934};
2935
2936static int mptcp_close_state(struct sock *sk)
2937{
2938 int next = (int)new_state[sk->sk_state];
2939 int ns = next & TCP_STATE_MASK;
2940
2941 mptcp_set_state(sk, ns);
2942
2943 return next & TCP_ACTION_FIN;
2944}
2945
2946static void mptcp_check_send_data_fin(struct sock *sk)
2947{
2948 struct mptcp_subflow_context *subflow;
2949 struct mptcp_sock *msk = mptcp_sk(sk);
2950
2951 pr_debug("msk=%p snd_data_fin_enable=%d pending=%d snd_nxt=%llu write_seq=%llu",
2952 msk, msk->snd_data_fin_enable, !!mptcp_send_head(sk),
2953 msk->snd_nxt, msk->write_seq);
2954
2955 /* we still need to enqueue subflows or not really shutting down,
2956 * skip this
2957 */
2958 if (!msk->snd_data_fin_enable || msk->snd_nxt + 1 != msk->write_seq ||
2959 mptcp_send_head(sk))
2960 return;
2961
2962 WRITE_ONCE(msk->snd_nxt, msk->write_seq);
2963
2964 mptcp_for_each_subflow(msk, subflow) {
2965 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
2966
2967 mptcp_subflow_shutdown(sk, tcp_sk, SEND_SHUTDOWN);
2968 }
2969}
2970
2971static void __mptcp_wr_shutdown(struct sock *sk)
2972{
2973 struct mptcp_sock *msk = mptcp_sk(sk);
2974
2975 pr_debug("msk=%p snd_data_fin_enable=%d shutdown=%x state=%d pending=%d",
2976 msk, msk->snd_data_fin_enable, sk->sk_shutdown, sk->sk_state,
2977 !!mptcp_send_head(sk));
2978
2979 /* will be ignored by fallback sockets */
2980 WRITE_ONCE(msk->write_seq, msk->write_seq + 1);
2981 WRITE_ONCE(msk->snd_data_fin_enable, 1);
2982
2983 mptcp_check_send_data_fin(sk);
2984}
2985
2986static void __mptcp_destroy_sock(struct sock *sk)
2987{
2988 struct mptcp_sock *msk = mptcp_sk(sk);
2989
2990 pr_debug("msk=%p", msk);
2991
2992 might_sleep();
2993
2994 mptcp_stop_rtx_timer(sk);
2995 sk_stop_timer(sk, &sk->sk_timer);
2996 msk->pm.status = 0;
2997 mptcp_release_sched(msk);
2998
2999 sk->sk_prot->destroy(sk);
3000
3001 WARN_ON_ONCE(READ_ONCE(msk->rmem_fwd_alloc));
3002 WARN_ON_ONCE(msk->rmem_released);
3003 sk_stream_kill_queues(sk);
3004 xfrm_sk_free_policy(sk);
3005
3006 sock_put(sk);
3007}
3008
3009void __mptcp_unaccepted_force_close(struct sock *sk)
3010{
3011 sock_set_flag(sk, SOCK_DEAD);
3012 mptcp_do_fastclose(sk);
3013 __mptcp_destroy_sock(sk);
3014}
3015
3016static __poll_t mptcp_check_readable(struct sock *sk)
3017{
3018 return mptcp_epollin_ready(sk) ? EPOLLIN | EPOLLRDNORM : 0;
3019}
3020
3021static void mptcp_check_listen_stop(struct sock *sk)
3022{
3023 struct sock *ssk;
3024
3025 if (inet_sk_state_load(sk) != TCP_LISTEN)
3026 return;
3027
3028 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
3029 ssk = mptcp_sk(sk)->first;
3030 if (WARN_ON_ONCE(!ssk || inet_sk_state_load(ssk) != TCP_LISTEN))
3031 return;
3032
3033 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
3034 tcp_set_state(ssk, TCP_CLOSE);
3035 mptcp_subflow_queue_clean(sk, ssk);
3036 inet_csk_listen_stop(ssk);
3037 mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CLOSED);
3038 release_sock(ssk);
3039}
3040
3041bool __mptcp_close(struct sock *sk, long timeout)
3042{
3043 struct mptcp_subflow_context *subflow;
3044 struct mptcp_sock *msk = mptcp_sk(sk);
3045 bool do_cancel_work = false;
3046 int subflows_alive = 0;
3047
3048 WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
3049
3050 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) {
3051 mptcp_check_listen_stop(sk);
3052 mptcp_set_state(sk, TCP_CLOSE);
3053 goto cleanup;
3054 }
3055
3056 if (mptcp_data_avail(msk) || timeout < 0) {
3057 /* If the msk has read data, or the caller explicitly ask it,
3058 * do the MPTCP equivalent of TCP reset, aka MPTCP fastclose
3059 */
3060 mptcp_do_fastclose(sk);
3061 timeout = 0;
3062 } else if (mptcp_close_state(sk)) {
3063 __mptcp_wr_shutdown(sk);
3064 }
3065
3066 sk_stream_wait_close(sk, timeout);
3067
3068cleanup:
3069 /* orphan all the subflows */
3070 mptcp_for_each_subflow(msk, subflow) {
3071 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3072 bool slow = lock_sock_fast_nested(ssk);
3073
3074 subflows_alive += ssk->sk_state != TCP_CLOSE;
3075
3076 /* since the close timeout takes precedence on the fail one,
3077 * cancel the latter
3078 */
3079 if (ssk == msk->first)
3080 subflow->fail_tout = 0;
3081
3082 /* detach from the parent socket, but allow data_ready to
3083 * push incoming data into the mptcp stack, to properly ack it
3084 */
3085 ssk->sk_socket = NULL;
3086 ssk->sk_wq = NULL;
3087 unlock_sock_fast(ssk, slow);
3088 }
3089 sock_orphan(sk);
3090
3091 /* all the subflows are closed, only timeout can change the msk
3092 * state, let's not keep resources busy for no reasons
3093 */
3094 if (subflows_alive == 0)
3095 mptcp_set_state(sk, TCP_CLOSE);
3096
3097 sock_hold(sk);
3098 pr_debug("msk=%p state=%d", sk, sk->sk_state);
3099 if (msk->token)
3100 mptcp_event(MPTCP_EVENT_CLOSED, msk, NULL, GFP_KERNEL);
3101
3102 if (sk->sk_state == TCP_CLOSE) {
3103 __mptcp_destroy_sock(sk);
3104 do_cancel_work = true;
3105 } else {
3106 mptcp_start_tout_timer(sk);
3107 }
3108
3109 return do_cancel_work;
3110}
3111
3112static void mptcp_close(struct sock *sk, long timeout)
3113{
3114 bool do_cancel_work;
3115
3116 lock_sock(sk);
3117
3118 do_cancel_work = __mptcp_close(sk, timeout);
3119 release_sock(sk);
3120 if (do_cancel_work)
3121 mptcp_cancel_work(sk);
3122
3123 sock_put(sk);
3124}
3125
3126static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk)
3127{
3128#if IS_ENABLED(CONFIG_MPTCP_IPV6)
3129 const struct ipv6_pinfo *ssk6 = inet6_sk(ssk);
3130 struct ipv6_pinfo *msk6 = inet6_sk(msk);
3131
3132 msk->sk_v6_daddr = ssk->sk_v6_daddr;
3133 msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr;
3134
3135 if (msk6 && ssk6) {
3136 msk6->saddr = ssk6->saddr;
3137 msk6->flow_label = ssk6->flow_label;
3138 }
3139#endif
3140
3141 inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num;
3142 inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport;
3143 inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport;
3144 inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr;
3145 inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr;
3146 inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr;
3147}
3148
3149static int mptcp_disconnect(struct sock *sk, int flags)
3150{
3151 struct mptcp_sock *msk = mptcp_sk(sk);
3152
3153 /* We are on the fastopen error path. We can't call straight into the
3154 * subflows cleanup code due to lock nesting (we are already under
3155 * msk->firstsocket lock).
3156 */
3157 if (msk->fastopening)
3158 return -EBUSY;
3159
3160 mptcp_check_listen_stop(sk);
3161 mptcp_set_state(sk, TCP_CLOSE);
3162
3163 mptcp_stop_rtx_timer(sk);
3164 mptcp_stop_tout_timer(sk);
3165
3166 if (msk->token)
3167 mptcp_event(MPTCP_EVENT_CLOSED, msk, NULL, GFP_KERNEL);
3168
3169 /* msk->subflow is still intact, the following will not free the first
3170 * subflow
3171 */
3172 mptcp_destroy_common(msk, MPTCP_CF_FASTCLOSE);
3173 WRITE_ONCE(msk->flags, 0);
3174 msk->cb_flags = 0;
3175 msk->recovery = false;
3176 WRITE_ONCE(msk->can_ack, false);
3177 WRITE_ONCE(msk->fully_established, false);
3178 WRITE_ONCE(msk->rcv_data_fin, false);
3179 WRITE_ONCE(msk->snd_data_fin_enable, false);
3180 WRITE_ONCE(msk->rcv_fastclose, false);
3181 WRITE_ONCE(msk->use_64bit_ack, false);
3182 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
3183 mptcp_pm_data_reset(msk);
3184 mptcp_ca_reset(sk);
3185 msk->bytes_consumed = 0;
3186 msk->bytes_acked = 0;
3187 msk->bytes_received = 0;
3188 msk->bytes_sent = 0;
3189 msk->bytes_retrans = 0;
3190 msk->rcvspace_init = 0;
3191
3192 WRITE_ONCE(sk->sk_shutdown, 0);
3193 sk_error_report(sk);
3194 return 0;
3195}
3196
3197#if IS_ENABLED(CONFIG_MPTCP_IPV6)
3198static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk)
3199{
3200 unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo);
3201
3202 return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
3203}
3204
3205static void mptcp_copy_ip6_options(struct sock *newsk, const struct sock *sk)
3206{
3207 const struct ipv6_pinfo *np = inet6_sk(sk);
3208 struct ipv6_txoptions *opt;
3209 struct ipv6_pinfo *newnp;
3210
3211 newnp = inet6_sk(newsk);
3212
3213 rcu_read_lock();
3214 opt = rcu_dereference(np->opt);
3215 if (opt) {
3216 opt = ipv6_dup_options(newsk, opt);
3217 if (!opt)
3218 net_warn_ratelimited("%s: Failed to copy ip6 options\n", __func__);
3219 }
3220 RCU_INIT_POINTER(newnp->opt, opt);
3221 rcu_read_unlock();
3222}
3223#endif
3224
3225static void mptcp_copy_ip_options(struct sock *newsk, const struct sock *sk)
3226{
3227 struct ip_options_rcu *inet_opt, *newopt = NULL;
3228 const struct inet_sock *inet = inet_sk(sk);
3229 struct inet_sock *newinet;
3230
3231 newinet = inet_sk(newsk);
3232
3233 rcu_read_lock();
3234 inet_opt = rcu_dereference(inet->inet_opt);
3235 if (inet_opt) {
3236 newopt = sock_kmalloc(newsk, sizeof(*inet_opt) +
3237 inet_opt->opt.optlen, GFP_ATOMIC);
3238 if (newopt)
3239 memcpy(newopt, inet_opt, sizeof(*inet_opt) +
3240 inet_opt->opt.optlen);
3241 else
3242 net_warn_ratelimited("%s: Failed to copy ip options\n", __func__);
3243 }
3244 RCU_INIT_POINTER(newinet->inet_opt, newopt);
3245 rcu_read_unlock();
3246}
3247
3248struct sock *mptcp_sk_clone_init(const struct sock *sk,
3249 const struct mptcp_options_received *mp_opt,
3250 struct sock *ssk,
3251 struct request_sock *req)
3252{
3253 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
3254 struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC);
3255 struct mptcp_subflow_context *subflow;
3256 struct mptcp_sock *msk;
3257
3258 if (!nsk)
3259 return NULL;
3260
3261#if IS_ENABLED(CONFIG_MPTCP_IPV6)
3262 if (nsk->sk_family == AF_INET6)
3263 inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk);
3264#endif
3265
3266 __mptcp_init_sock(nsk);
3267
3268#if IS_ENABLED(CONFIG_MPTCP_IPV6)
3269 if (nsk->sk_family == AF_INET6)
3270 mptcp_copy_ip6_options(nsk, sk);
3271 else
3272#endif
3273 mptcp_copy_ip_options(nsk, sk);
3274
3275 msk = mptcp_sk(nsk);
3276 WRITE_ONCE(msk->local_key, subflow_req->local_key);
3277 WRITE_ONCE(msk->token, subflow_req->token);
3278 msk->in_accept_queue = 1;
3279 WRITE_ONCE(msk->fully_established, false);
3280 if (mp_opt->suboptions & OPTION_MPTCP_CSUMREQD)
3281 WRITE_ONCE(msk->csum_enabled, true);
3282
3283 WRITE_ONCE(msk->write_seq, subflow_req->idsn + 1);
3284 WRITE_ONCE(msk->snd_nxt, msk->write_seq);
3285 WRITE_ONCE(msk->snd_una, msk->write_seq);
3286 WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd);
3287 msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq;
3288 mptcp_init_sched(msk, mptcp_sk(sk)->sched);
3289
3290 /* passive msk is created after the first/MPC subflow */
3291 msk->subflow_id = 2;
3292
3293 sock_reset_flag(nsk, SOCK_RCU_FREE);
3294 security_inet_csk_clone(nsk, req);
3295
3296 /* this can't race with mptcp_close(), as the msk is
3297 * not yet exposted to user-space
3298 */
3299 mptcp_set_state(nsk, TCP_ESTABLISHED);
3300
3301 /* The msk maintain a ref to each subflow in the connections list */
3302 WRITE_ONCE(msk->first, ssk);
3303 subflow = mptcp_subflow_ctx(ssk);
3304 list_add(&subflow->node, &msk->conn_list);
3305 sock_hold(ssk);
3306
3307 /* new mpc subflow takes ownership of the newly
3308 * created mptcp socket
3309 */
3310 mptcp_token_accept(subflow_req, msk);
3311
3312 /* set msk addresses early to ensure mptcp_pm_get_local_id()
3313 * uses the correct data
3314 */
3315 mptcp_copy_inaddrs(nsk, ssk);
3316 __mptcp_propagate_sndbuf(nsk, ssk);
3317
3318 mptcp_rcv_space_init(msk, ssk);
3319
3320 if (mp_opt->suboptions & OPTION_MPTCP_MPC_ACK)
3321 __mptcp_subflow_fully_established(msk, subflow, mp_opt);
3322 bh_unlock_sock(nsk);
3323
3324 /* note: the newly allocated socket refcount is 2 now */
3325 return nsk;
3326}
3327
3328void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk)
3329{
3330 const struct tcp_sock *tp = tcp_sk(ssk);
3331
3332 msk->rcvspace_init = 1;
3333 msk->rcvq_space.copied = 0;
3334 msk->rcvq_space.rtt_us = 0;
3335
3336 msk->rcvq_space.time = tp->tcp_mstamp;
3337
3338 /* initial rcv_space offering made to peer */
3339 msk->rcvq_space.space = min_t(u32, tp->rcv_wnd,
3340 TCP_INIT_CWND * tp->advmss);
3341 if (msk->rcvq_space.space == 0)
3342 msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT;
3343}
3344
3345void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags)
3346{
3347 struct mptcp_subflow_context *subflow, *tmp;
3348 struct sock *sk = (struct sock *)msk;
3349
3350 __mptcp_clear_xmit(sk);
3351
3352 /* join list will be eventually flushed (with rst) at sock lock release time */
3353 mptcp_for_each_subflow_safe(msk, subflow, tmp)
3354 __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), subflow, flags);
3355
3356 /* move to sk_receive_queue, sk_stream_kill_queues will purge it */
3357 mptcp_data_lock(sk);
3358 skb_queue_splice_tail_init(&msk->receive_queue, &sk->sk_receive_queue);
3359 __skb_queue_purge(&sk->sk_receive_queue);
3360 skb_rbtree_purge(&msk->out_of_order_queue);
3361 mptcp_data_unlock(sk);
3362
3363 /* move all the rx fwd alloc into the sk_mem_reclaim_final in
3364 * inet_sock_destruct() will dispose it
3365 */
3366 sk_forward_alloc_add(sk, msk->rmem_fwd_alloc);
3367 WRITE_ONCE(msk->rmem_fwd_alloc, 0);
3368 mptcp_token_destroy(msk);
3369 mptcp_pm_free_anno_list(msk);
3370 mptcp_free_local_addr_list(msk);
3371}
3372
3373static void mptcp_destroy(struct sock *sk)
3374{
3375 struct mptcp_sock *msk = mptcp_sk(sk);
3376
3377 /* allow the following to close even the initial subflow */
3378 msk->free_first = 1;
3379 mptcp_destroy_common(msk, 0);
3380 sk_sockets_allocated_dec(sk);
3381}
3382
3383void __mptcp_data_acked(struct sock *sk)
3384{
3385 if (!sock_owned_by_user(sk))
3386 __mptcp_clean_una(sk);
3387 else
3388 __set_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->cb_flags);
3389}
3390
3391void __mptcp_check_push(struct sock *sk, struct sock *ssk)
3392{
3393 if (!mptcp_send_head(sk))
3394 return;
3395
3396 if (!sock_owned_by_user(sk))
3397 __mptcp_subflow_push_pending(sk, ssk, false);
3398 else
3399 __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags);
3400}
3401
3402#define MPTCP_FLAGS_PROCESS_CTX_NEED (BIT(MPTCP_PUSH_PENDING) | \
3403 BIT(MPTCP_RETRANSMIT) | \
3404 BIT(MPTCP_FLUSH_JOIN_LIST))
3405
3406/* processes deferred events and flush wmem */
3407static void mptcp_release_cb(struct sock *sk)
3408 __must_hold(&sk->sk_lock.slock)
3409{
3410 struct mptcp_sock *msk = mptcp_sk(sk);
3411
3412 for (;;) {
3413 unsigned long flags = (msk->cb_flags & MPTCP_FLAGS_PROCESS_CTX_NEED);
3414 struct list_head join_list;
3415
3416 if (!flags)
3417 break;
3418
3419 INIT_LIST_HEAD(&join_list);
3420 list_splice_init(&msk->join_list, &join_list);
3421
3422 /* the following actions acquire the subflow socket lock
3423 *
3424 * 1) can't be invoked in atomic scope
3425 * 2) must avoid ABBA deadlock with msk socket spinlock: the RX
3426 * datapath acquires the msk socket spinlock while helding
3427 * the subflow socket lock
3428 */
3429 msk->cb_flags &= ~flags;
3430 spin_unlock_bh(&sk->sk_lock.slock);
3431
3432 if (flags & BIT(MPTCP_FLUSH_JOIN_LIST))
3433 __mptcp_flush_join_list(sk, &join_list);
3434 if (flags & BIT(MPTCP_PUSH_PENDING))
3435 __mptcp_push_pending(sk, 0);
3436 if (flags & BIT(MPTCP_RETRANSMIT))
3437 __mptcp_retrans(sk);
3438
3439 cond_resched();
3440 spin_lock_bh(&sk->sk_lock.slock);
3441 }
3442
3443 if (__test_and_clear_bit(MPTCP_CLEAN_UNA, &msk->cb_flags))
3444 __mptcp_clean_una_wakeup(sk);
3445 if (unlikely(msk->cb_flags)) {
3446 /* be sure to sync the msk state before taking actions
3447 * depending on sk_state (MPTCP_ERROR_REPORT)
3448 * On sk release avoid actions depending on the first subflow
3449 */
3450 if (__test_and_clear_bit(MPTCP_SYNC_STATE, &msk->cb_flags) && msk->first)
3451 __mptcp_sync_state(sk, msk->pending_state);
3452 if (__test_and_clear_bit(MPTCP_ERROR_REPORT, &msk->cb_flags))
3453 __mptcp_error_report(sk);
3454 if (__test_and_clear_bit(MPTCP_SYNC_SNDBUF, &msk->cb_flags))
3455 __mptcp_sync_sndbuf(sk);
3456 }
3457
3458 __mptcp_update_rmem(sk);
3459}
3460
3461/* MP_JOIN client subflow must wait for 4th ack before sending any data:
3462 * TCP can't schedule delack timer before the subflow is fully established.
3463 * MPTCP uses the delack timer to do 3rd ack retransmissions
3464 */
3465static void schedule_3rdack_retransmission(struct sock *ssk)
3466{
3467 struct inet_connection_sock *icsk = inet_csk(ssk);
3468 struct tcp_sock *tp = tcp_sk(ssk);
3469 unsigned long timeout;
3470
3471 if (mptcp_subflow_ctx(ssk)->fully_established)
3472 return;
3473
3474 /* reschedule with a timeout above RTT, as we must look only for drop */
3475 if (tp->srtt_us)
3476 timeout = usecs_to_jiffies(tp->srtt_us >> (3 - 1));
3477 else
3478 timeout = TCP_TIMEOUT_INIT;
3479 timeout += jiffies;
3480
3481 WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER);
3482 icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
3483 icsk->icsk_ack.timeout = timeout;
3484 sk_reset_timer(ssk, &icsk->icsk_delack_timer, timeout);
3485}
3486
3487void mptcp_subflow_process_delegated(struct sock *ssk, long status)
3488{
3489 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
3490 struct sock *sk = subflow->conn;
3491
3492 if (status & BIT(MPTCP_DELEGATE_SEND)) {
3493 mptcp_data_lock(sk);
3494 if (!sock_owned_by_user(sk))
3495 __mptcp_subflow_push_pending(sk, ssk, true);
3496 else
3497 __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags);
3498 mptcp_data_unlock(sk);
3499 }
3500 if (status & BIT(MPTCP_DELEGATE_SNDBUF)) {
3501 mptcp_data_lock(sk);
3502 if (!sock_owned_by_user(sk))
3503 __mptcp_sync_sndbuf(sk);
3504 else
3505 __set_bit(MPTCP_SYNC_SNDBUF, &mptcp_sk(sk)->cb_flags);
3506 mptcp_data_unlock(sk);
3507 }
3508 if (status & BIT(MPTCP_DELEGATE_ACK))
3509 schedule_3rdack_retransmission(ssk);
3510}
3511
3512static int mptcp_hash(struct sock *sk)
3513{
3514 /* should never be called,
3515 * we hash the TCP subflows not the master socket
3516 */
3517 WARN_ON_ONCE(1);
3518 return 0;
3519}
3520
3521static void mptcp_unhash(struct sock *sk)
3522{
3523 /* called from sk_common_release(), but nothing to do here */
3524}
3525
3526static int mptcp_get_port(struct sock *sk, unsigned short snum)
3527{
3528 struct mptcp_sock *msk = mptcp_sk(sk);
3529
3530 pr_debug("msk=%p, ssk=%p", msk, msk->first);
3531 if (WARN_ON_ONCE(!msk->first))
3532 return -EINVAL;
3533
3534 return inet_csk_get_port(msk->first, snum);
3535}
3536
3537void mptcp_finish_connect(struct sock *ssk)
3538{
3539 struct mptcp_subflow_context *subflow;
3540 struct mptcp_sock *msk;
3541 struct sock *sk;
3542
3543 subflow = mptcp_subflow_ctx(ssk);
3544 sk = subflow->conn;
3545 msk = mptcp_sk(sk);
3546
3547 pr_debug("msk=%p, token=%u", sk, subflow->token);
3548
3549 subflow->map_seq = subflow->iasn;
3550 subflow->map_subflow_seq = 1;
3551
3552 /* the socket is not connected yet, no msk/subflow ops can access/race
3553 * accessing the field below
3554 */
3555 WRITE_ONCE(msk->local_key, subflow->local_key);
3556
3557 mptcp_pm_new_connection(msk, ssk, 0);
3558}
3559
3560void mptcp_sock_graft(struct sock *sk, struct socket *parent)
3561{
3562 write_lock_bh(&sk->sk_callback_lock);
3563 rcu_assign_pointer(sk->sk_wq, &parent->wq);
3564 sk_set_socket(sk, parent);
3565 sk->sk_uid = SOCK_INODE(parent)->i_uid;
3566 write_unlock_bh(&sk->sk_callback_lock);
3567}
3568
3569bool mptcp_finish_join(struct sock *ssk)
3570{
3571 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
3572 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
3573 struct sock *parent = (void *)msk;
3574 bool ret = true;
3575
3576 pr_debug("msk=%p, subflow=%p", msk, subflow);
3577
3578 /* mptcp socket already closing? */
3579 if (!mptcp_is_fully_established(parent)) {
3580 subflow->reset_reason = MPTCP_RST_EMPTCP;
3581 return false;
3582 }
3583
3584 /* active subflow, already present inside the conn_list */
3585 if (!list_empty(&subflow->node)) {
3586 mptcp_subflow_joined(msk, ssk);
3587 mptcp_propagate_sndbuf(parent, ssk);
3588 return true;
3589 }
3590
3591 if (!mptcp_pm_allow_new_subflow(msk))
3592 goto err_prohibited;
3593
3594 /* If we can't acquire msk socket lock here, let the release callback
3595 * handle it
3596 */
3597 mptcp_data_lock(parent);
3598 if (!sock_owned_by_user(parent)) {
3599 ret = __mptcp_finish_join(msk, ssk);
3600 if (ret) {
3601 sock_hold(ssk);
3602 list_add_tail(&subflow->node, &msk->conn_list);
3603 }
3604 } else {
3605 sock_hold(ssk);
3606 list_add_tail(&subflow->node, &msk->join_list);
3607 __set_bit(MPTCP_FLUSH_JOIN_LIST, &msk->cb_flags);
3608 }
3609 mptcp_data_unlock(parent);
3610
3611 if (!ret) {
3612err_prohibited:
3613 subflow->reset_reason = MPTCP_RST_EPROHIBIT;
3614 return false;
3615 }
3616
3617 return true;
3618}
3619
3620static void mptcp_shutdown(struct sock *sk, int how)
3621{
3622 pr_debug("sk=%p, how=%d", sk, how);
3623
3624 if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk))
3625 __mptcp_wr_shutdown(sk);
3626}
3627
3628static int mptcp_forward_alloc_get(const struct sock *sk)
3629{
3630 return READ_ONCE(sk->sk_forward_alloc) +
3631 READ_ONCE(mptcp_sk(sk)->rmem_fwd_alloc);
3632}
3633
3634static int mptcp_ioctl_outq(const struct mptcp_sock *msk, u64 v)
3635{
3636 const struct sock *sk = (void *)msk;
3637 u64 delta;
3638
3639 if (sk->sk_state == TCP_LISTEN)
3640 return -EINVAL;
3641
3642 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
3643 return 0;
3644
3645 delta = msk->write_seq - v;
3646 if (__mptcp_check_fallback(msk) && msk->first) {
3647 struct tcp_sock *tp = tcp_sk(msk->first);
3648
3649 /* the first subflow is disconnected after close - see
3650 * __mptcp_close_ssk(). tcp_disconnect() moves the write_seq
3651 * so ignore that status, too.
3652 */
3653 if (!((1 << msk->first->sk_state) &
3654 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE)))
3655 delta += READ_ONCE(tp->write_seq) - tp->snd_una;
3656 }
3657 if (delta > INT_MAX)
3658 delta = INT_MAX;
3659
3660 return (int)delta;
3661}
3662
3663static int mptcp_ioctl(struct sock *sk, int cmd, int *karg)
3664{
3665 struct mptcp_sock *msk = mptcp_sk(sk);
3666 bool slow;
3667
3668 switch (cmd) {
3669 case SIOCINQ:
3670 if (sk->sk_state == TCP_LISTEN)
3671 return -EINVAL;
3672
3673 lock_sock(sk);
3674 __mptcp_move_skbs(msk);
3675 *karg = mptcp_inq_hint(sk);
3676 release_sock(sk);
3677 break;
3678 case SIOCOUTQ:
3679 slow = lock_sock_fast(sk);
3680 *karg = mptcp_ioctl_outq(msk, READ_ONCE(msk->snd_una));
3681 unlock_sock_fast(sk, slow);
3682 break;
3683 case SIOCOUTQNSD:
3684 slow = lock_sock_fast(sk);
3685 *karg = mptcp_ioctl_outq(msk, msk->snd_nxt);
3686 unlock_sock_fast(sk, slow);
3687 break;
3688 default:
3689 return -ENOIOCTLCMD;
3690 }
3691
3692 return 0;
3693}
3694
3695static void mptcp_subflow_early_fallback(struct mptcp_sock *msk,
3696 struct mptcp_subflow_context *subflow)
3697{
3698 subflow->request_mptcp = 0;
3699 __mptcp_do_fallback(msk);
3700}
3701
3702static int mptcp_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
3703{
3704 struct mptcp_subflow_context *subflow;
3705 struct mptcp_sock *msk = mptcp_sk(sk);
3706 int err = -EINVAL;
3707 struct sock *ssk;
3708
3709 ssk = __mptcp_nmpc_sk(msk);
3710 if (IS_ERR(ssk))
3711 return PTR_ERR(ssk);
3712
3713 mptcp_set_state(sk, TCP_SYN_SENT);
3714 subflow = mptcp_subflow_ctx(ssk);
3715#ifdef CONFIG_TCP_MD5SIG
3716 /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
3717 * TCP option space.
3718 */
3719 if (rcu_access_pointer(tcp_sk(ssk)->md5sig_info))
3720 mptcp_subflow_early_fallback(msk, subflow);
3721#endif
3722 if (subflow->request_mptcp && mptcp_token_new_connect(ssk)) {
3723 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_TOKENFALLBACKINIT);
3724 mptcp_subflow_early_fallback(msk, subflow);
3725 }
3726
3727 WRITE_ONCE(msk->write_seq, subflow->idsn);
3728 WRITE_ONCE(msk->snd_nxt, subflow->idsn);
3729 if (likely(!__mptcp_check_fallback(msk)))
3730 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVE);
3731
3732 /* if reaching here via the fastopen/sendmsg path, the caller already
3733 * acquired the subflow socket lock, too.
3734 */
3735 if (!msk->fastopening)
3736 lock_sock(ssk);
3737
3738 /* the following mirrors closely a very small chunk of code from
3739 * __inet_stream_connect()
3740 */
3741 if (ssk->sk_state != TCP_CLOSE)
3742 goto out;
3743
3744 if (BPF_CGROUP_PRE_CONNECT_ENABLED(ssk)) {
3745 err = ssk->sk_prot->pre_connect(ssk, uaddr, addr_len);
3746 if (err)
3747 goto out;
3748 }
3749
3750 err = ssk->sk_prot->connect(ssk, uaddr, addr_len);
3751 if (err < 0)
3752 goto out;
3753
3754 inet_assign_bit(DEFER_CONNECT, sk, inet_test_bit(DEFER_CONNECT, ssk));
3755
3756out:
3757 if (!msk->fastopening)
3758 release_sock(ssk);
3759
3760 /* on successful connect, the msk state will be moved to established by
3761 * subflow_finish_connect()
3762 */
3763 if (unlikely(err)) {
3764 /* avoid leaving a dangling token in an unconnected socket */
3765 mptcp_token_destroy(msk);
3766 mptcp_set_state(sk, TCP_CLOSE);
3767 return err;
3768 }
3769
3770 mptcp_copy_inaddrs(sk, ssk);
3771 return 0;
3772}
3773
3774static struct proto mptcp_prot = {
3775 .name = "MPTCP",
3776 .owner = THIS_MODULE,
3777 .init = mptcp_init_sock,
3778 .connect = mptcp_connect,
3779 .disconnect = mptcp_disconnect,
3780 .close = mptcp_close,
3781 .setsockopt = mptcp_setsockopt,
3782 .getsockopt = mptcp_getsockopt,
3783 .shutdown = mptcp_shutdown,
3784 .destroy = mptcp_destroy,
3785 .sendmsg = mptcp_sendmsg,
3786 .ioctl = mptcp_ioctl,
3787 .recvmsg = mptcp_recvmsg,
3788 .release_cb = mptcp_release_cb,
3789 .hash = mptcp_hash,
3790 .unhash = mptcp_unhash,
3791 .get_port = mptcp_get_port,
3792 .forward_alloc_get = mptcp_forward_alloc_get,
3793 .stream_memory_free = mptcp_stream_memory_free,
3794 .sockets_allocated = &mptcp_sockets_allocated,
3795
3796 .memory_allocated = &tcp_memory_allocated,
3797 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc,
3798
3799 .memory_pressure = &tcp_memory_pressure,
3800 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
3801 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
3802 .sysctl_mem = sysctl_tcp_mem,
3803 .obj_size = sizeof(struct mptcp_sock),
3804 .slab_flags = SLAB_TYPESAFE_BY_RCU,
3805 .no_autobind = true,
3806};
3807
3808static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
3809{
3810 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3811 struct sock *ssk, *sk = sock->sk;
3812 int err = -EINVAL;
3813
3814 lock_sock(sk);
3815 ssk = __mptcp_nmpc_sk(msk);
3816 if (IS_ERR(ssk)) {
3817 err = PTR_ERR(ssk);
3818 goto unlock;
3819 }
3820
3821 if (sk->sk_family == AF_INET)
3822 err = inet_bind_sk(ssk, uaddr, addr_len);
3823#if IS_ENABLED(CONFIG_MPTCP_IPV6)
3824 else if (sk->sk_family == AF_INET6)
3825 err = inet6_bind_sk(ssk, uaddr, addr_len);
3826#endif
3827 if (!err)
3828 mptcp_copy_inaddrs(sk, ssk);
3829
3830unlock:
3831 release_sock(sk);
3832 return err;
3833}
3834
3835static int mptcp_listen(struct socket *sock, int backlog)
3836{
3837 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3838 struct sock *sk = sock->sk;
3839 struct sock *ssk;
3840 int err;
3841
3842 pr_debug("msk=%p", msk);
3843
3844 lock_sock(sk);
3845
3846 err = -EINVAL;
3847 if (sock->state != SS_UNCONNECTED || sock->type != SOCK_STREAM)
3848 goto unlock;
3849
3850 ssk = __mptcp_nmpc_sk(msk);
3851 if (IS_ERR(ssk)) {
3852 err = PTR_ERR(ssk);
3853 goto unlock;
3854 }
3855
3856 mptcp_set_state(sk, TCP_LISTEN);
3857 sock_set_flag(sk, SOCK_RCU_FREE);
3858
3859 lock_sock(ssk);
3860 err = __inet_listen_sk(ssk, backlog);
3861 release_sock(ssk);
3862 mptcp_set_state(sk, inet_sk_state_load(ssk));
3863
3864 if (!err) {
3865 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
3866 mptcp_copy_inaddrs(sk, ssk);
3867 mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CREATED);
3868 }
3869
3870unlock:
3871 release_sock(sk);
3872 return err;
3873}
3874
3875static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
3876 int flags, bool kern)
3877{
3878 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3879 struct sock *ssk, *newsk;
3880 int err;
3881
3882 pr_debug("msk=%p", msk);
3883
3884 /* Buggy applications can call accept on socket states other then LISTEN
3885 * but no need to allocate the first subflow just to error out.
3886 */
3887 ssk = READ_ONCE(msk->first);
3888 if (!ssk)
3889 return -EINVAL;
3890
3891 pr_debug("ssk=%p, listener=%p", ssk, mptcp_subflow_ctx(ssk));
3892 newsk = inet_csk_accept(ssk, flags, &err, kern);
3893 if (!newsk)
3894 return err;
3895
3896 pr_debug("newsk=%p, subflow is mptcp=%d", newsk, sk_is_mptcp(newsk));
3897 if (sk_is_mptcp(newsk)) {
3898 struct mptcp_subflow_context *subflow;
3899 struct sock *new_mptcp_sock;
3900
3901 subflow = mptcp_subflow_ctx(newsk);
3902 new_mptcp_sock = subflow->conn;
3903
3904 /* is_mptcp should be false if subflow->conn is missing, see
3905 * subflow_syn_recv_sock()
3906 */
3907 if (WARN_ON_ONCE(!new_mptcp_sock)) {
3908 tcp_sk(newsk)->is_mptcp = 0;
3909 goto tcpfallback;
3910 }
3911
3912 newsk = new_mptcp_sock;
3913 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_MPCAPABLEPASSIVEACK);
3914
3915 newsk->sk_kern_sock = kern;
3916 lock_sock(newsk);
3917 __inet_accept(sock, newsock, newsk);
3918
3919 set_bit(SOCK_CUSTOM_SOCKOPT, &newsock->flags);
3920 msk = mptcp_sk(newsk);
3921 msk->in_accept_queue = 0;
3922
3923 /* set ssk->sk_socket of accept()ed flows to mptcp socket.
3924 * This is needed so NOSPACE flag can be set from tcp stack.
3925 */
3926 mptcp_for_each_subflow(msk, subflow) {
3927 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3928
3929 if (!ssk->sk_socket)
3930 mptcp_sock_graft(ssk, newsock);
3931 }
3932
3933 /* Do late cleanup for the first subflow as necessary. Also
3934 * deal with bad peers not doing a complete shutdown.
3935 */
3936 if (unlikely(inet_sk_state_load(msk->first) == TCP_CLOSE)) {
3937 __mptcp_close_ssk(newsk, msk->first,
3938 mptcp_subflow_ctx(msk->first), 0);
3939 if (unlikely(list_is_singular(&msk->conn_list)))
3940 mptcp_set_state(newsk, TCP_CLOSE);
3941 }
3942 } else {
3943tcpfallback:
3944 newsk->sk_kern_sock = kern;
3945 lock_sock(newsk);
3946 __inet_accept(sock, newsock, newsk);
3947 /* we are being invoked after accepting a non-mp-capable
3948 * flow: sk is a tcp_sk, not an mptcp one.
3949 *
3950 * Hand the socket over to tcp so all further socket ops
3951 * bypass mptcp.
3952 */
3953 WRITE_ONCE(newsock->sk->sk_socket->ops,
3954 mptcp_fallback_tcp_ops(newsock->sk));
3955 }
3956 release_sock(newsk);
3957
3958 return 0;
3959}
3960
3961static __poll_t mptcp_check_writeable(struct mptcp_sock *msk)
3962{
3963 struct sock *sk = (struct sock *)msk;
3964
3965 if (__mptcp_stream_is_writeable(sk, 1))
3966 return EPOLLOUT | EPOLLWRNORM;
3967
3968 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
3969 smp_mb__after_atomic(); /* NOSPACE is changed by mptcp_write_space() */
3970 if (__mptcp_stream_is_writeable(sk, 1))
3971 return EPOLLOUT | EPOLLWRNORM;
3972
3973 return 0;
3974}
3975
3976static __poll_t mptcp_poll(struct file *file, struct socket *sock,
3977 struct poll_table_struct *wait)
3978{
3979 struct sock *sk = sock->sk;
3980 struct mptcp_sock *msk;
3981 __poll_t mask = 0;
3982 u8 shutdown;
3983 int state;
3984
3985 msk = mptcp_sk(sk);
3986 sock_poll_wait(file, sock, wait);
3987
3988 state = inet_sk_state_load(sk);
3989 pr_debug("msk=%p state=%d flags=%lx", msk, state, msk->flags);
3990 if (state == TCP_LISTEN) {
3991 struct sock *ssk = READ_ONCE(msk->first);
3992
3993 if (WARN_ON_ONCE(!ssk))
3994 return 0;
3995
3996 return inet_csk_listen_poll(ssk);
3997 }
3998
3999 shutdown = READ_ONCE(sk->sk_shutdown);
4000 if (shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
4001 mask |= EPOLLHUP;
4002 if (shutdown & RCV_SHUTDOWN)
4003 mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
4004
4005 if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) {
4006 mask |= mptcp_check_readable(sk);
4007 if (shutdown & SEND_SHUTDOWN)
4008 mask |= EPOLLOUT | EPOLLWRNORM;
4009 else
4010 mask |= mptcp_check_writeable(msk);
4011 } else if (state == TCP_SYN_SENT &&
4012 inet_test_bit(DEFER_CONNECT, sk)) {
4013 /* cf tcp_poll() note about TFO */
4014 mask |= EPOLLOUT | EPOLLWRNORM;
4015 }
4016
4017 /* This barrier is coupled with smp_wmb() in __mptcp_error_report() */
4018 smp_rmb();
4019 if (READ_ONCE(sk->sk_err))
4020 mask |= EPOLLERR;
4021
4022 return mask;
4023}
4024
4025static const struct proto_ops mptcp_stream_ops = {
4026 .family = PF_INET,
4027 .owner = THIS_MODULE,
4028 .release = inet_release,
4029 .bind = mptcp_bind,
4030 .connect = inet_stream_connect,
4031 .socketpair = sock_no_socketpair,
4032 .accept = mptcp_stream_accept,
4033 .getname = inet_getname,
4034 .poll = mptcp_poll,
4035 .ioctl = inet_ioctl,
4036 .gettstamp = sock_gettstamp,
4037 .listen = mptcp_listen,
4038 .shutdown = inet_shutdown,
4039 .setsockopt = sock_common_setsockopt,
4040 .getsockopt = sock_common_getsockopt,
4041 .sendmsg = inet_sendmsg,
4042 .recvmsg = inet_recvmsg,
4043 .mmap = sock_no_mmap,
4044 .set_rcvlowat = mptcp_set_rcvlowat,
4045};
4046
4047static struct inet_protosw mptcp_protosw = {
4048 .type = SOCK_STREAM,
4049 .protocol = IPPROTO_MPTCP,
4050 .prot = &mptcp_prot,
4051 .ops = &mptcp_stream_ops,
4052 .flags = INET_PROTOSW_ICSK,
4053};
4054
4055static int mptcp_napi_poll(struct napi_struct *napi, int budget)
4056{
4057 struct mptcp_delegated_action *delegated;
4058 struct mptcp_subflow_context *subflow;
4059 int work_done = 0;
4060
4061 delegated = container_of(napi, struct mptcp_delegated_action, napi);
4062 while ((subflow = mptcp_subflow_delegated_next(delegated)) != NULL) {
4063 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
4064
4065 bh_lock_sock_nested(ssk);
4066 if (!sock_owned_by_user(ssk)) {
4067 mptcp_subflow_process_delegated(ssk, xchg(&subflow->delegated_status, 0));
4068 } else {
4069 /* tcp_release_cb_override already processed
4070 * the action or will do at next release_sock().
4071 * In both case must dequeue the subflow here - on the same
4072 * CPU that scheduled it.
4073 */
4074 smp_wmb();
4075 clear_bit(MPTCP_DELEGATE_SCHEDULED, &subflow->delegated_status);
4076 }
4077 bh_unlock_sock(ssk);
4078 sock_put(ssk);
4079
4080 if (++work_done == budget)
4081 return budget;
4082 }
4083
4084 /* always provide a 0 'work_done' argument, so that napi_complete_done
4085 * will not try accessing the NULL napi->dev ptr
4086 */
4087 napi_complete_done(napi, 0);
4088 return work_done;
4089}
4090
4091void __init mptcp_proto_init(void)
4092{
4093 struct mptcp_delegated_action *delegated;
4094 int cpu;
4095
4096 mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo;
4097
4098 if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL))
4099 panic("Failed to allocate MPTCP pcpu counter\n");
4100
4101 init_dummy_netdev(&mptcp_napi_dev);
4102 for_each_possible_cpu(cpu) {
4103 delegated = per_cpu_ptr(&mptcp_delegated_actions, cpu);
4104 INIT_LIST_HEAD(&delegated->head);
4105 netif_napi_add_tx(&mptcp_napi_dev, &delegated->napi,
4106 mptcp_napi_poll);
4107 napi_enable(&delegated->napi);
4108 }
4109
4110 mptcp_subflow_init();
4111 mptcp_pm_init();
4112 mptcp_sched_init();
4113 mptcp_token_init();
4114
4115 if (proto_register(&mptcp_prot, 1) != 0)
4116 panic("Failed to register MPTCP proto.\n");
4117
4118 inet_register_protosw(&mptcp_protosw);
4119
4120 BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb));
4121}
4122
4123#if IS_ENABLED(CONFIG_MPTCP_IPV6)
4124static const struct proto_ops mptcp_v6_stream_ops = {
4125 .family = PF_INET6,
4126 .owner = THIS_MODULE,
4127 .release = inet6_release,
4128 .bind = mptcp_bind,
4129 .connect = inet_stream_connect,
4130 .socketpair = sock_no_socketpair,
4131 .accept = mptcp_stream_accept,
4132 .getname = inet6_getname,
4133 .poll = mptcp_poll,
4134 .ioctl = inet6_ioctl,
4135 .gettstamp = sock_gettstamp,
4136 .listen = mptcp_listen,
4137 .shutdown = inet_shutdown,
4138 .setsockopt = sock_common_setsockopt,
4139 .getsockopt = sock_common_getsockopt,
4140 .sendmsg = inet6_sendmsg,
4141 .recvmsg = inet6_recvmsg,
4142 .mmap = sock_no_mmap,
4143#ifdef CONFIG_COMPAT
4144 .compat_ioctl = inet6_compat_ioctl,
4145#endif
4146 .set_rcvlowat = mptcp_set_rcvlowat,
4147};
4148
4149static struct proto mptcp_v6_prot;
4150
4151static struct inet_protosw mptcp_v6_protosw = {
4152 .type = SOCK_STREAM,
4153 .protocol = IPPROTO_MPTCP,
4154 .prot = &mptcp_v6_prot,
4155 .ops = &mptcp_v6_stream_ops,
4156 .flags = INET_PROTOSW_ICSK,
4157};
4158
4159int __init mptcp_proto_v6_init(void)
4160{
4161 int err;
4162
4163 mptcp_v6_prot = mptcp_prot;
4164 strcpy(mptcp_v6_prot.name, "MPTCPv6");
4165 mptcp_v6_prot.slab = NULL;
4166 mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock);
4167 mptcp_v6_prot.ipv6_pinfo_offset = offsetof(struct mptcp6_sock, np);
4168
4169 err = proto_register(&mptcp_v6_prot, 1);
4170 if (err)
4171 return err;
4172
4173 err = inet6_register_protosw(&mptcp_v6_protosw);
4174 if (err)
4175 proto_unregister(&mptcp_v6_prot);
4176
4177 return err;
4178}
4179#endif