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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_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/hotdata.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/* Returns end sequence number of the receiver's advertised window */
53static u64 mptcp_wnd_end(const struct mptcp_sock *msk)
54{
55 return READ_ONCE(msk->wnd_end);
56}
57
58static const struct proto_ops *mptcp_fallback_tcp_ops(const struct sock *sk)
59{
60#if IS_ENABLED(CONFIG_MPTCP_IPV6)
61 if (sk->sk_prot == &tcpv6_prot)
62 return &inet6_stream_ops;
63#endif
64 WARN_ON_ONCE(sk->sk_prot != &tcp_prot);
65 return &inet_stream_ops;
66}
67
68static int __mptcp_socket_create(struct mptcp_sock *msk)
69{
70 struct mptcp_subflow_context *subflow;
71 struct sock *sk = (struct sock *)msk;
72 struct socket *ssock;
73 int err;
74
75 err = mptcp_subflow_create_socket(sk, sk->sk_family, &ssock);
76 if (err)
77 return err;
78
79 msk->scaling_ratio = tcp_sk(ssock->sk)->scaling_ratio;
80 WRITE_ONCE(msk->first, ssock->sk);
81 subflow = mptcp_subflow_ctx(ssock->sk);
82 list_add(&subflow->node, &msk->conn_list);
83 sock_hold(ssock->sk);
84 subflow->request_mptcp = 1;
85 subflow->subflow_id = msk->subflow_id++;
86
87 /* This is the first subflow, always with id 0 */
88 WRITE_ONCE(subflow->local_id, 0);
89 mptcp_sock_graft(msk->first, sk->sk_socket);
90 iput(SOCK_INODE(ssock));
91
92 return 0;
93}
94
95/* If the MPC handshake is not started, returns the first subflow,
96 * eventually allocating it.
97 */
98struct sock *__mptcp_nmpc_sk(struct mptcp_sock *msk)
99{
100 struct sock *sk = (struct sock *)msk;
101 int ret;
102
103 if (!((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
104 return ERR_PTR(-EINVAL);
105
106 if (!msk->first) {
107 ret = __mptcp_socket_create(msk);
108 if (ret)
109 return ERR_PTR(ret);
110 }
111
112 return msk->first;
113}
114
115static void mptcp_drop(struct sock *sk, struct sk_buff *skb)
116{
117 sk_drops_add(sk, skb);
118 __kfree_skb(skb);
119}
120
121static void mptcp_rmem_fwd_alloc_add(struct sock *sk, int size)
122{
123 WRITE_ONCE(mptcp_sk(sk)->rmem_fwd_alloc,
124 mptcp_sk(sk)->rmem_fwd_alloc + size);
125}
126
127static void mptcp_rmem_charge(struct sock *sk, int size)
128{
129 mptcp_rmem_fwd_alloc_add(sk, -size);
130}
131
132static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to,
133 struct sk_buff *from)
134{
135 bool fragstolen;
136 int delta;
137
138 if (MPTCP_SKB_CB(from)->offset ||
139 ((to->len + from->len) > (sk->sk_rcvbuf >> 3)) ||
140 !skb_try_coalesce(to, from, &fragstolen, &delta))
141 return false;
142
143 pr_debug("colesced seq %llx into %llx new len %d new end seq %llx\n",
144 MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq,
145 to->len, MPTCP_SKB_CB(from)->end_seq);
146 MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq;
147
148 /* note the fwd memory can reach a negative value after accounting
149 * for the delta, but the later skb free will restore a non
150 * negative one
151 */
152 atomic_add(delta, &sk->sk_rmem_alloc);
153 mptcp_rmem_charge(sk, delta);
154 kfree_skb_partial(from, fragstolen);
155
156 return true;
157}
158
159static bool mptcp_ooo_try_coalesce(struct mptcp_sock *msk, struct sk_buff *to,
160 struct sk_buff *from)
161{
162 if (MPTCP_SKB_CB(from)->map_seq != MPTCP_SKB_CB(to)->end_seq)
163 return false;
164
165 return mptcp_try_coalesce((struct sock *)msk, to, from);
166}
167
168static void __mptcp_rmem_reclaim(struct sock *sk, int amount)
169{
170 amount >>= PAGE_SHIFT;
171 mptcp_rmem_charge(sk, amount << PAGE_SHIFT);
172 __sk_mem_reduce_allocated(sk, amount);
173}
174
175static void mptcp_rmem_uncharge(struct sock *sk, int size)
176{
177 struct mptcp_sock *msk = mptcp_sk(sk);
178 int reclaimable;
179
180 mptcp_rmem_fwd_alloc_add(sk, size);
181 reclaimable = msk->rmem_fwd_alloc - sk_unused_reserved_mem(sk);
182
183 /* see sk_mem_uncharge() for the rationale behind the following schema */
184 if (unlikely(reclaimable >= PAGE_SIZE))
185 __mptcp_rmem_reclaim(sk, reclaimable);
186}
187
188static void mptcp_rfree(struct sk_buff *skb)
189{
190 unsigned int len = skb->truesize;
191 struct sock *sk = skb->sk;
192
193 atomic_sub(len, &sk->sk_rmem_alloc);
194 mptcp_rmem_uncharge(sk, len);
195}
196
197void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk)
198{
199 skb_orphan(skb);
200 skb->sk = sk;
201 skb->destructor = mptcp_rfree;
202 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
203 mptcp_rmem_charge(sk, skb->truesize);
204}
205
206/* "inspired" by tcp_data_queue_ofo(), main differences:
207 * - use mptcp seqs
208 * - don't cope with sacks
209 */
210static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb)
211{
212 struct sock *sk = (struct sock *)msk;
213 struct rb_node **p, *parent;
214 u64 seq, end_seq, max_seq;
215 struct sk_buff *skb1;
216
217 seq = MPTCP_SKB_CB(skb)->map_seq;
218 end_seq = MPTCP_SKB_CB(skb)->end_seq;
219 max_seq = atomic64_read(&msk->rcv_wnd_sent);
220
221 pr_debug("msk=%p seq=%llx limit=%llx empty=%d\n", msk, seq, max_seq,
222 RB_EMPTY_ROOT(&msk->out_of_order_queue));
223 if (after64(end_seq, max_seq)) {
224 /* out of window */
225 mptcp_drop(sk, skb);
226 pr_debug("oow by %lld, rcv_wnd_sent %llu\n",
227 (unsigned long long)end_seq - (unsigned long)max_seq,
228 (unsigned long long)atomic64_read(&msk->rcv_wnd_sent));
229 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_NODSSWINDOW);
230 return;
231 }
232
233 p = &msk->out_of_order_queue.rb_node;
234 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUE);
235 if (RB_EMPTY_ROOT(&msk->out_of_order_queue)) {
236 rb_link_node(&skb->rbnode, NULL, p);
237 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
238 msk->ooo_last_skb = skb;
239 goto end;
240 }
241
242 /* with 2 subflows, adding at end of ooo queue is quite likely
243 * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup.
244 */
245 if (mptcp_ooo_try_coalesce(msk, msk->ooo_last_skb, skb)) {
246 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
247 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
248 return;
249 }
250
251 /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */
252 if (!before64(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) {
253 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
254 parent = &msk->ooo_last_skb->rbnode;
255 p = &parent->rb_right;
256 goto insert;
257 }
258
259 /* Find place to insert this segment. Handle overlaps on the way. */
260 parent = NULL;
261 while (*p) {
262 parent = *p;
263 skb1 = rb_to_skb(parent);
264 if (before64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
265 p = &parent->rb_left;
266 continue;
267 }
268 if (before64(seq, MPTCP_SKB_CB(skb1)->end_seq)) {
269 if (!after64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) {
270 /* All the bits are present. Drop. */
271 mptcp_drop(sk, skb);
272 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
273 return;
274 }
275 if (after64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
276 /* partial overlap:
277 * | skb |
278 * | skb1 |
279 * continue traversing
280 */
281 } else {
282 /* skb's seq == skb1's seq and skb covers skb1.
283 * Replace skb1 with skb.
284 */
285 rb_replace_node(&skb1->rbnode, &skb->rbnode,
286 &msk->out_of_order_queue);
287 mptcp_drop(sk, skb1);
288 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
289 goto merge_right;
290 }
291 } else if (mptcp_ooo_try_coalesce(msk, skb1, skb)) {
292 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
293 return;
294 }
295 p = &parent->rb_right;
296 }
297
298insert:
299 /* Insert segment into RB tree. */
300 rb_link_node(&skb->rbnode, parent, p);
301 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
302
303merge_right:
304 /* Remove other segments covered by skb. */
305 while ((skb1 = skb_rb_next(skb)) != NULL) {
306 if (before64(end_seq, MPTCP_SKB_CB(skb1)->end_seq))
307 break;
308 rb_erase(&skb1->rbnode, &msk->out_of_order_queue);
309 mptcp_drop(sk, skb1);
310 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
311 }
312 /* If there is no skb after us, we are the last_skb ! */
313 if (!skb1)
314 msk->ooo_last_skb = skb;
315
316end:
317 skb_condense(skb);
318 mptcp_set_owner_r(skb, sk);
319}
320
321static bool mptcp_rmem_schedule(struct sock *sk, struct sock *ssk, int size)
322{
323 struct mptcp_sock *msk = mptcp_sk(sk);
324 int amt, amount;
325
326 if (size <= msk->rmem_fwd_alloc)
327 return true;
328
329 size -= msk->rmem_fwd_alloc;
330 amt = sk_mem_pages(size);
331 amount = amt << PAGE_SHIFT;
332 if (!__sk_mem_raise_allocated(sk, size, amt, SK_MEM_RECV))
333 return false;
334
335 mptcp_rmem_fwd_alloc_add(sk, amount);
336 return true;
337}
338
339static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk,
340 struct sk_buff *skb, unsigned int offset,
341 size_t copy_len)
342{
343 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
344 struct sock *sk = (struct sock *)msk;
345 struct sk_buff *tail;
346 bool has_rxtstamp;
347
348 __skb_unlink(skb, &ssk->sk_receive_queue);
349
350 skb_ext_reset(skb);
351 skb_orphan(skb);
352
353 /* try to fetch required memory from subflow */
354 if (!mptcp_rmem_schedule(sk, ssk, skb->truesize)) {
355 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED);
356 goto drop;
357 }
358
359 has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp;
360
361 /* the skb map_seq accounts for the skb offset:
362 * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq
363 * value
364 */
365 MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow);
366 MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len;
367 MPTCP_SKB_CB(skb)->offset = offset;
368 MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp;
369
370 if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) {
371 /* in sequence */
372 msk->bytes_received += copy_len;
373 WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len);
374 tail = skb_peek_tail(&sk->sk_receive_queue);
375 if (tail && mptcp_try_coalesce(sk, tail, skb))
376 return true;
377
378 mptcp_set_owner_r(skb, sk);
379 __skb_queue_tail(&sk->sk_receive_queue, skb);
380 return true;
381 } else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) {
382 mptcp_data_queue_ofo(msk, skb);
383 return false;
384 }
385
386 /* old data, keep it simple and drop the whole pkt, sender
387 * will retransmit as needed, if needed.
388 */
389 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
390drop:
391 mptcp_drop(sk, skb);
392 return false;
393}
394
395static void mptcp_stop_rtx_timer(struct sock *sk)
396{
397 struct inet_connection_sock *icsk = inet_csk(sk);
398
399 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
400 mptcp_sk(sk)->timer_ival = 0;
401}
402
403static void mptcp_close_wake_up(struct sock *sk)
404{
405 if (sock_flag(sk, SOCK_DEAD))
406 return;
407
408 sk->sk_state_change(sk);
409 if (sk->sk_shutdown == SHUTDOWN_MASK ||
410 sk->sk_state == TCP_CLOSE)
411 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
412 else
413 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
414}
415
416/* called under the msk socket lock */
417static bool mptcp_pending_data_fin_ack(struct sock *sk)
418{
419 struct mptcp_sock *msk = mptcp_sk(sk);
420
421 return ((1 << sk->sk_state) &
422 (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) &&
423 msk->write_seq == READ_ONCE(msk->snd_una);
424}
425
426static void mptcp_check_data_fin_ack(struct sock *sk)
427{
428 struct mptcp_sock *msk = mptcp_sk(sk);
429
430 /* Look for an acknowledged DATA_FIN */
431 if (mptcp_pending_data_fin_ack(sk)) {
432 WRITE_ONCE(msk->snd_data_fin_enable, 0);
433
434 switch (sk->sk_state) {
435 case TCP_FIN_WAIT1:
436 mptcp_set_state(sk, TCP_FIN_WAIT2);
437 break;
438 case TCP_CLOSING:
439 case TCP_LAST_ACK:
440 mptcp_set_state(sk, TCP_CLOSE);
441 break;
442 }
443
444 mptcp_close_wake_up(sk);
445 }
446}
447
448/* can be called with no lock acquired */
449static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq)
450{
451 struct mptcp_sock *msk = mptcp_sk(sk);
452
453 if (READ_ONCE(msk->rcv_data_fin) &&
454 ((1 << inet_sk_state_load(sk)) &
455 (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) {
456 u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq);
457
458 if (READ_ONCE(msk->ack_seq) == rcv_data_fin_seq) {
459 if (seq)
460 *seq = rcv_data_fin_seq;
461
462 return true;
463 }
464 }
465
466 return false;
467}
468
469static void mptcp_set_datafin_timeout(struct sock *sk)
470{
471 struct inet_connection_sock *icsk = inet_csk(sk);
472 u32 retransmits;
473
474 retransmits = min_t(u32, icsk->icsk_retransmits,
475 ilog2(TCP_RTO_MAX / TCP_RTO_MIN));
476
477 mptcp_sk(sk)->timer_ival = TCP_RTO_MIN << retransmits;
478}
479
480static void __mptcp_set_timeout(struct sock *sk, long tout)
481{
482 mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
483}
484
485static long mptcp_timeout_from_subflow(const struct mptcp_subflow_context *subflow)
486{
487 const struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
488
489 return inet_csk(ssk)->icsk_pending && !subflow->stale_count ?
490 inet_csk(ssk)->icsk_timeout - jiffies : 0;
491}
492
493static void mptcp_set_timeout(struct sock *sk)
494{
495 struct mptcp_subflow_context *subflow;
496 long tout = 0;
497
498 mptcp_for_each_subflow(mptcp_sk(sk), subflow)
499 tout = max(tout, mptcp_timeout_from_subflow(subflow));
500 __mptcp_set_timeout(sk, tout);
501}
502
503static inline bool tcp_can_send_ack(const struct sock *ssk)
504{
505 return !((1 << inet_sk_state_load(ssk)) &
506 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE | TCPF_LISTEN));
507}
508
509void __mptcp_subflow_send_ack(struct sock *ssk)
510{
511 if (tcp_can_send_ack(ssk))
512 tcp_send_ack(ssk);
513}
514
515static void mptcp_subflow_send_ack(struct sock *ssk)
516{
517 bool slow;
518
519 slow = lock_sock_fast(ssk);
520 __mptcp_subflow_send_ack(ssk);
521 unlock_sock_fast(ssk, slow);
522}
523
524static void mptcp_send_ack(struct mptcp_sock *msk)
525{
526 struct mptcp_subflow_context *subflow;
527
528 mptcp_for_each_subflow(msk, subflow)
529 mptcp_subflow_send_ack(mptcp_subflow_tcp_sock(subflow));
530}
531
532static void mptcp_subflow_cleanup_rbuf(struct sock *ssk, int copied)
533{
534 bool slow;
535
536 slow = lock_sock_fast(ssk);
537 if (tcp_can_send_ack(ssk))
538 tcp_cleanup_rbuf(ssk, copied);
539 unlock_sock_fast(ssk, slow);
540}
541
542static bool mptcp_subflow_could_cleanup(const struct sock *ssk, bool rx_empty)
543{
544 const struct inet_connection_sock *icsk = inet_csk(ssk);
545 u8 ack_pending = READ_ONCE(icsk->icsk_ack.pending);
546 const struct tcp_sock *tp = tcp_sk(ssk);
547
548 return (ack_pending & ICSK_ACK_SCHED) &&
549 ((READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->rcv_wup) >
550 READ_ONCE(icsk->icsk_ack.rcv_mss)) ||
551 (rx_empty && ack_pending &
552 (ICSK_ACK_PUSHED2 | ICSK_ACK_PUSHED)));
553}
554
555static void mptcp_cleanup_rbuf(struct mptcp_sock *msk, int copied)
556{
557 int old_space = READ_ONCE(msk->old_wspace);
558 struct mptcp_subflow_context *subflow;
559 struct sock *sk = (struct sock *)msk;
560 int space = __mptcp_space(sk);
561 bool cleanup, rx_empty;
562
563 cleanup = (space > 0) && (space >= (old_space << 1)) && copied;
564 rx_empty = !__mptcp_rmem(sk) && copied;
565
566 mptcp_for_each_subflow(msk, subflow) {
567 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
568
569 if (cleanup || mptcp_subflow_could_cleanup(ssk, rx_empty))
570 mptcp_subflow_cleanup_rbuf(ssk, copied);
571 }
572}
573
574static bool mptcp_check_data_fin(struct sock *sk)
575{
576 struct mptcp_sock *msk = mptcp_sk(sk);
577 u64 rcv_data_fin_seq;
578 bool ret = false;
579
580 /* Need to ack a DATA_FIN received from a peer while this side
581 * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2.
582 * msk->rcv_data_fin was set when parsing the incoming options
583 * at the subflow level and the msk lock was not held, so this
584 * is the first opportunity to act on the DATA_FIN and change
585 * the msk state.
586 *
587 * If we are caught up to the sequence number of the incoming
588 * DATA_FIN, send the DATA_ACK now and do state transition. If
589 * not caught up, do nothing and let the recv code send DATA_ACK
590 * when catching up.
591 */
592
593 if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) {
594 WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1);
595 WRITE_ONCE(msk->rcv_data_fin, 0);
596
597 WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | RCV_SHUTDOWN);
598 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
599
600 switch (sk->sk_state) {
601 case TCP_ESTABLISHED:
602 mptcp_set_state(sk, TCP_CLOSE_WAIT);
603 break;
604 case TCP_FIN_WAIT1:
605 mptcp_set_state(sk, TCP_CLOSING);
606 break;
607 case TCP_FIN_WAIT2:
608 mptcp_set_state(sk, TCP_CLOSE);
609 break;
610 default:
611 /* Other states not expected */
612 WARN_ON_ONCE(1);
613 break;
614 }
615
616 ret = true;
617 if (!__mptcp_check_fallback(msk))
618 mptcp_send_ack(msk);
619 mptcp_close_wake_up(sk);
620 }
621 return ret;
622}
623
624static void mptcp_dss_corruption(struct mptcp_sock *msk, struct sock *ssk)
625{
626 if (READ_ONCE(msk->allow_infinite_fallback)) {
627 MPTCP_INC_STATS(sock_net(ssk),
628 MPTCP_MIB_DSSCORRUPTIONFALLBACK);
629 mptcp_do_fallback(ssk);
630 } else {
631 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DSSCORRUPTIONRESET);
632 mptcp_subflow_reset(ssk);
633 }
634}
635
636static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
637 struct sock *ssk,
638 unsigned int *bytes)
639{
640 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
641 struct sock *sk = (struct sock *)msk;
642 unsigned int moved = 0;
643 bool more_data_avail;
644 struct tcp_sock *tp;
645 bool done = false;
646 int sk_rbuf;
647
648 sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
649
650 if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
651 int ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
652
653 if (unlikely(ssk_rbuf > sk_rbuf)) {
654 WRITE_ONCE(sk->sk_rcvbuf, ssk_rbuf);
655 sk_rbuf = ssk_rbuf;
656 }
657 }
658
659 pr_debug("msk=%p ssk=%p\n", msk, ssk);
660 tp = tcp_sk(ssk);
661 do {
662 u32 map_remaining, offset;
663 u32 seq = tp->copied_seq;
664 struct sk_buff *skb;
665 bool fin;
666
667 /* try to move as much data as available */
668 map_remaining = subflow->map_data_len -
669 mptcp_subflow_get_map_offset(subflow);
670
671 skb = skb_peek(&ssk->sk_receive_queue);
672 if (!skb) {
673 /* With racing move_skbs_to_msk() and __mptcp_move_skbs(),
674 * a different CPU can have already processed the pending
675 * data, stop here or we can enter an infinite loop
676 */
677 if (!moved)
678 done = true;
679 break;
680 }
681
682 if (__mptcp_check_fallback(msk)) {
683 /* Under fallback skbs have no MPTCP extension and TCP could
684 * collapse them between the dummy map creation and the
685 * current dequeue. Be sure to adjust the map size.
686 */
687 map_remaining = skb->len;
688 subflow->map_data_len = skb->len;
689 }
690
691 offset = seq - TCP_SKB_CB(skb)->seq;
692 fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
693 if (fin) {
694 done = true;
695 seq++;
696 }
697
698 if (offset < skb->len) {
699 size_t len = skb->len - offset;
700
701 if (tp->urg_data)
702 done = true;
703
704 if (__mptcp_move_skb(msk, ssk, skb, offset, len))
705 moved += len;
706 seq += len;
707
708 if (unlikely(map_remaining < len)) {
709 DEBUG_NET_WARN_ON_ONCE(1);
710 mptcp_dss_corruption(msk, ssk);
711 }
712 } else {
713 if (unlikely(!fin)) {
714 DEBUG_NET_WARN_ON_ONCE(1);
715 mptcp_dss_corruption(msk, ssk);
716 }
717
718 sk_eat_skb(ssk, skb);
719 done = true;
720 }
721
722 WRITE_ONCE(tp->copied_seq, seq);
723 more_data_avail = mptcp_subflow_data_available(ssk);
724
725 if (atomic_read(&sk->sk_rmem_alloc) > sk_rbuf) {
726 done = true;
727 break;
728 }
729 } while (more_data_avail);
730
731 if (moved > 0)
732 msk->last_data_recv = tcp_jiffies32;
733 *bytes += moved;
734 return done;
735}
736
737static bool __mptcp_ofo_queue(struct mptcp_sock *msk)
738{
739 struct sock *sk = (struct sock *)msk;
740 struct sk_buff *skb, *tail;
741 bool moved = false;
742 struct rb_node *p;
743 u64 end_seq;
744
745 p = rb_first(&msk->out_of_order_queue);
746 pr_debug("msk=%p empty=%d\n", msk, RB_EMPTY_ROOT(&msk->out_of_order_queue));
747 while (p) {
748 skb = rb_to_skb(p);
749 if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq))
750 break;
751
752 p = rb_next(p);
753 rb_erase(&skb->rbnode, &msk->out_of_order_queue);
754
755 if (unlikely(!after64(MPTCP_SKB_CB(skb)->end_seq,
756 msk->ack_seq))) {
757 mptcp_drop(sk, skb);
758 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
759 continue;
760 }
761
762 end_seq = MPTCP_SKB_CB(skb)->end_seq;
763 tail = skb_peek_tail(&sk->sk_receive_queue);
764 if (!tail || !mptcp_ooo_try_coalesce(msk, tail, skb)) {
765 int delta = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq;
766
767 /* skip overlapping data, if any */
768 pr_debug("uncoalesced seq=%llx ack seq=%llx delta=%d\n",
769 MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq,
770 delta);
771 MPTCP_SKB_CB(skb)->offset += delta;
772 MPTCP_SKB_CB(skb)->map_seq += delta;
773 __skb_queue_tail(&sk->sk_receive_queue, skb);
774 }
775 msk->bytes_received += end_seq - msk->ack_seq;
776 WRITE_ONCE(msk->ack_seq, end_seq);
777 moved = true;
778 }
779 return moved;
780}
781
782static bool __mptcp_subflow_error_report(struct sock *sk, struct sock *ssk)
783{
784 int err = sock_error(ssk);
785 int ssk_state;
786
787 if (!err)
788 return false;
789
790 /* only propagate errors on fallen-back sockets or
791 * on MPC connect
792 */
793 if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(mptcp_sk(sk)))
794 return false;
795
796 /* We need to propagate only transition to CLOSE state.
797 * Orphaned socket will see such state change via
798 * subflow_sched_work_if_closed() and that path will properly
799 * destroy the msk as needed.
800 */
801 ssk_state = inet_sk_state_load(ssk);
802 if (ssk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DEAD))
803 mptcp_set_state(sk, ssk_state);
804 WRITE_ONCE(sk->sk_err, -err);
805
806 /* This barrier is coupled with smp_rmb() in mptcp_poll() */
807 smp_wmb();
808 sk_error_report(sk);
809 return true;
810}
811
812void __mptcp_error_report(struct sock *sk)
813{
814 struct mptcp_subflow_context *subflow;
815 struct mptcp_sock *msk = mptcp_sk(sk);
816
817 mptcp_for_each_subflow(msk, subflow)
818 if (__mptcp_subflow_error_report(sk, mptcp_subflow_tcp_sock(subflow)))
819 break;
820}
821
822/* In most cases we will be able to lock the mptcp socket. If its already
823 * owned, we need to defer to the work queue to avoid ABBA deadlock.
824 */
825static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk)
826{
827 struct sock *sk = (struct sock *)msk;
828 unsigned int moved = 0;
829
830 __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
831 __mptcp_ofo_queue(msk);
832 if (unlikely(ssk->sk_err)) {
833 if (!sock_owned_by_user(sk))
834 __mptcp_error_report(sk);
835 else
836 __set_bit(MPTCP_ERROR_REPORT, &msk->cb_flags);
837 }
838
839 /* If the moves have caught up with the DATA_FIN sequence number
840 * it's time to ack the DATA_FIN and change socket state, but
841 * this is not a good place to change state. Let the workqueue
842 * do it.
843 */
844 if (mptcp_pending_data_fin(sk, NULL))
845 mptcp_schedule_work(sk);
846 return moved > 0;
847}
848
849void mptcp_data_ready(struct sock *sk, struct sock *ssk)
850{
851 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
852 struct mptcp_sock *msk = mptcp_sk(sk);
853 int sk_rbuf, ssk_rbuf;
854
855 /* The peer can send data while we are shutting down this
856 * subflow at msk destruction time, but we must avoid enqueuing
857 * more data to the msk receive queue
858 */
859 if (unlikely(subflow->disposable))
860 return;
861
862 ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
863 sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
864 if (unlikely(ssk_rbuf > sk_rbuf))
865 sk_rbuf = ssk_rbuf;
866
867 /* over limit? can't append more skbs to msk, Also, no need to wake-up*/
868 if (__mptcp_rmem(sk) > sk_rbuf)
869 return;
870
871 /* Wake-up the reader only for in-sequence data */
872 mptcp_data_lock(sk);
873 if (move_skbs_to_msk(msk, ssk) && mptcp_epollin_ready(sk))
874 sk->sk_data_ready(sk);
875 mptcp_data_unlock(sk);
876}
877
878static void mptcp_subflow_joined(struct mptcp_sock *msk, struct sock *ssk)
879{
880 mptcp_subflow_ctx(ssk)->map_seq = READ_ONCE(msk->ack_seq);
881 WRITE_ONCE(msk->allow_infinite_fallback, false);
882 mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC);
883}
884
885static bool __mptcp_finish_join(struct mptcp_sock *msk, struct sock *ssk)
886{
887 struct sock *sk = (struct sock *)msk;
888
889 if (sk->sk_state != TCP_ESTABLISHED)
890 return false;
891
892 /* attach to msk socket only after we are sure we will deal with it
893 * at close time
894 */
895 if (sk->sk_socket && !ssk->sk_socket)
896 mptcp_sock_graft(ssk, sk->sk_socket);
897
898 mptcp_subflow_ctx(ssk)->subflow_id = msk->subflow_id++;
899 mptcp_sockopt_sync_locked(msk, ssk);
900 mptcp_subflow_joined(msk, ssk);
901 mptcp_stop_tout_timer(sk);
902 __mptcp_propagate_sndbuf(sk, ssk);
903 return true;
904}
905
906static void __mptcp_flush_join_list(struct sock *sk, struct list_head *join_list)
907{
908 struct mptcp_subflow_context *tmp, *subflow;
909 struct mptcp_sock *msk = mptcp_sk(sk);
910
911 list_for_each_entry_safe(subflow, tmp, join_list, node) {
912 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
913 bool slow = lock_sock_fast(ssk);
914
915 list_move_tail(&subflow->node, &msk->conn_list);
916 if (!__mptcp_finish_join(msk, ssk))
917 mptcp_subflow_reset(ssk);
918 unlock_sock_fast(ssk, slow);
919 }
920}
921
922static bool mptcp_rtx_timer_pending(struct sock *sk)
923{
924 return timer_pending(&inet_csk(sk)->icsk_retransmit_timer);
925}
926
927static void mptcp_reset_rtx_timer(struct sock *sk)
928{
929 struct inet_connection_sock *icsk = inet_csk(sk);
930 unsigned long tout;
931
932 /* prevent rescheduling on close */
933 if (unlikely(inet_sk_state_load(sk) == TCP_CLOSE))
934 return;
935
936 tout = mptcp_sk(sk)->timer_ival;
937 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout);
938}
939
940bool mptcp_schedule_work(struct sock *sk)
941{
942 if (inet_sk_state_load(sk) != TCP_CLOSE &&
943 schedule_work(&mptcp_sk(sk)->work)) {
944 /* each subflow already holds a reference to the sk, and the
945 * workqueue is invoked by a subflow, so sk can't go away here.
946 */
947 sock_hold(sk);
948 return true;
949 }
950 return false;
951}
952
953static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk)
954{
955 struct mptcp_subflow_context *subflow;
956
957 msk_owned_by_me(msk);
958
959 mptcp_for_each_subflow(msk, subflow) {
960 if (READ_ONCE(subflow->data_avail))
961 return mptcp_subflow_tcp_sock(subflow);
962 }
963
964 return NULL;
965}
966
967static bool mptcp_skb_can_collapse_to(u64 write_seq,
968 const struct sk_buff *skb,
969 const struct mptcp_ext *mpext)
970{
971 if (!tcp_skb_can_collapse_to(skb))
972 return false;
973
974 /* can collapse only if MPTCP level sequence is in order and this
975 * mapping has not been xmitted yet
976 */
977 return mpext && mpext->data_seq + mpext->data_len == write_seq &&
978 !mpext->frozen;
979}
980
981/* we can append data to the given data frag if:
982 * - there is space available in the backing page_frag
983 * - the data frag tail matches the current page_frag free offset
984 * - the data frag end sequence number matches the current write seq
985 */
986static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk,
987 const struct page_frag *pfrag,
988 const struct mptcp_data_frag *df)
989{
990 return df && pfrag->page == df->page &&
991 pfrag->size - pfrag->offset > 0 &&
992 pfrag->offset == (df->offset + df->data_len) &&
993 df->data_seq + df->data_len == msk->write_seq;
994}
995
996static void dfrag_uncharge(struct sock *sk, int len)
997{
998 sk_mem_uncharge(sk, len);
999 sk_wmem_queued_add(sk, -len);
1000}
1001
1002static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag)
1003{
1004 int len = dfrag->data_len + dfrag->overhead;
1005
1006 list_del(&dfrag->list);
1007 dfrag_uncharge(sk, len);
1008 put_page(dfrag->page);
1009}
1010
1011/* called under both the msk socket lock and the data lock */
1012static void __mptcp_clean_una(struct sock *sk)
1013{
1014 struct mptcp_sock *msk = mptcp_sk(sk);
1015 struct mptcp_data_frag *dtmp, *dfrag;
1016 u64 snd_una;
1017
1018 snd_una = msk->snd_una;
1019 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) {
1020 if (after64(dfrag->data_seq + dfrag->data_len, snd_una))
1021 break;
1022
1023 if (unlikely(dfrag == msk->first_pending)) {
1024 /* in recovery mode can see ack after the current snd head */
1025 if (WARN_ON_ONCE(!msk->recovery))
1026 break;
1027
1028 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1029 }
1030
1031 dfrag_clear(sk, dfrag);
1032 }
1033
1034 dfrag = mptcp_rtx_head(sk);
1035 if (dfrag && after64(snd_una, dfrag->data_seq)) {
1036 u64 delta = snd_una - dfrag->data_seq;
1037
1038 /* prevent wrap around in recovery mode */
1039 if (unlikely(delta > dfrag->already_sent)) {
1040 if (WARN_ON_ONCE(!msk->recovery))
1041 goto out;
1042 if (WARN_ON_ONCE(delta > dfrag->data_len))
1043 goto out;
1044 dfrag->already_sent += delta - dfrag->already_sent;
1045 }
1046
1047 dfrag->data_seq += delta;
1048 dfrag->offset += delta;
1049 dfrag->data_len -= delta;
1050 dfrag->already_sent -= delta;
1051
1052 dfrag_uncharge(sk, delta);
1053 }
1054
1055 /* all retransmitted data acked, recovery completed */
1056 if (unlikely(msk->recovery) && after64(msk->snd_una, msk->recovery_snd_nxt))
1057 msk->recovery = false;
1058
1059out:
1060 if (snd_una == msk->snd_nxt && snd_una == msk->write_seq) {
1061 if (mptcp_rtx_timer_pending(sk) && !mptcp_data_fin_enabled(msk))
1062 mptcp_stop_rtx_timer(sk);
1063 } else {
1064 mptcp_reset_rtx_timer(sk);
1065 }
1066
1067 if (mptcp_pending_data_fin_ack(sk))
1068 mptcp_schedule_work(sk);
1069}
1070
1071static void __mptcp_clean_una_wakeup(struct sock *sk)
1072{
1073 lockdep_assert_held_once(&sk->sk_lock.slock);
1074
1075 __mptcp_clean_una(sk);
1076 mptcp_write_space(sk);
1077}
1078
1079static void mptcp_clean_una_wakeup(struct sock *sk)
1080{
1081 mptcp_data_lock(sk);
1082 __mptcp_clean_una_wakeup(sk);
1083 mptcp_data_unlock(sk);
1084}
1085
1086static void mptcp_enter_memory_pressure(struct sock *sk)
1087{
1088 struct mptcp_subflow_context *subflow;
1089 struct mptcp_sock *msk = mptcp_sk(sk);
1090 bool first = true;
1091
1092 mptcp_for_each_subflow(msk, subflow) {
1093 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
1094
1095 if (first)
1096 tcp_enter_memory_pressure(ssk);
1097 sk_stream_moderate_sndbuf(ssk);
1098
1099 first = false;
1100 }
1101 __mptcp_sync_sndbuf(sk);
1102}
1103
1104/* ensure we get enough memory for the frag hdr, beyond some minimal amount of
1105 * data
1106 */
1107static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag)
1108{
1109 if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag),
1110 pfrag, sk->sk_allocation)))
1111 return true;
1112
1113 mptcp_enter_memory_pressure(sk);
1114 return false;
1115}
1116
1117static struct mptcp_data_frag *
1118mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag,
1119 int orig_offset)
1120{
1121 int offset = ALIGN(orig_offset, sizeof(long));
1122 struct mptcp_data_frag *dfrag;
1123
1124 dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset);
1125 dfrag->data_len = 0;
1126 dfrag->data_seq = msk->write_seq;
1127 dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag);
1128 dfrag->offset = offset + sizeof(struct mptcp_data_frag);
1129 dfrag->already_sent = 0;
1130 dfrag->page = pfrag->page;
1131
1132 return dfrag;
1133}
1134
1135struct mptcp_sendmsg_info {
1136 int mss_now;
1137 int size_goal;
1138 u16 limit;
1139 u16 sent;
1140 unsigned int flags;
1141 bool data_lock_held;
1142};
1143
1144static int mptcp_check_allowed_size(const struct mptcp_sock *msk, struct sock *ssk,
1145 u64 data_seq, int avail_size)
1146{
1147 u64 window_end = mptcp_wnd_end(msk);
1148 u64 mptcp_snd_wnd;
1149
1150 if (__mptcp_check_fallback(msk))
1151 return avail_size;
1152
1153 mptcp_snd_wnd = window_end - data_seq;
1154 avail_size = min_t(unsigned int, mptcp_snd_wnd, avail_size);
1155
1156 if (unlikely(tcp_sk(ssk)->snd_wnd < mptcp_snd_wnd)) {
1157 tcp_sk(ssk)->snd_wnd = min_t(u64, U32_MAX, mptcp_snd_wnd);
1158 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_SNDWNDSHARED);
1159 }
1160
1161 return avail_size;
1162}
1163
1164static bool __mptcp_add_ext(struct sk_buff *skb, gfp_t gfp)
1165{
1166 struct skb_ext *mpext = __skb_ext_alloc(gfp);
1167
1168 if (!mpext)
1169 return false;
1170 __skb_ext_set(skb, SKB_EXT_MPTCP, mpext);
1171 return true;
1172}
1173
1174static struct sk_buff *__mptcp_do_alloc_tx_skb(struct sock *sk, gfp_t gfp)
1175{
1176 struct sk_buff *skb;
1177
1178 skb = alloc_skb_fclone(MAX_TCP_HEADER, gfp);
1179 if (likely(skb)) {
1180 if (likely(__mptcp_add_ext(skb, gfp))) {
1181 skb_reserve(skb, MAX_TCP_HEADER);
1182 skb->ip_summed = CHECKSUM_PARTIAL;
1183 INIT_LIST_HEAD(&skb->tcp_tsorted_anchor);
1184 return skb;
1185 }
1186 __kfree_skb(skb);
1187 } else {
1188 mptcp_enter_memory_pressure(sk);
1189 }
1190 return NULL;
1191}
1192
1193static struct sk_buff *__mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, gfp_t gfp)
1194{
1195 struct sk_buff *skb;
1196
1197 skb = __mptcp_do_alloc_tx_skb(sk, gfp);
1198 if (!skb)
1199 return NULL;
1200
1201 if (likely(sk_wmem_schedule(ssk, skb->truesize))) {
1202 tcp_skb_entail(ssk, skb);
1203 return skb;
1204 }
1205 tcp_skb_tsorted_anchor_cleanup(skb);
1206 kfree_skb(skb);
1207 return NULL;
1208}
1209
1210static struct sk_buff *mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, bool data_lock_held)
1211{
1212 gfp_t gfp = data_lock_held ? GFP_ATOMIC : sk->sk_allocation;
1213
1214 return __mptcp_alloc_tx_skb(sk, ssk, gfp);
1215}
1216
1217/* note: this always recompute the csum on the whole skb, even
1218 * if we just appended a single frag. More status info needed
1219 */
1220static void mptcp_update_data_checksum(struct sk_buff *skb, int added)
1221{
1222 struct mptcp_ext *mpext = mptcp_get_ext(skb);
1223 __wsum csum = ~csum_unfold(mpext->csum);
1224 int offset = skb->len - added;
1225
1226 mpext->csum = csum_fold(csum_block_add(csum, skb_checksum(skb, offset, added, 0), offset));
1227}
1228
1229static void mptcp_update_infinite_map(struct mptcp_sock *msk,
1230 struct sock *ssk,
1231 struct mptcp_ext *mpext)
1232{
1233 if (!mpext)
1234 return;
1235
1236 mpext->infinite_map = 1;
1237 mpext->data_len = 0;
1238
1239 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPTX);
1240 mptcp_subflow_ctx(ssk)->send_infinite_map = 0;
1241 pr_fallback(msk);
1242 mptcp_do_fallback(ssk);
1243}
1244
1245#define MPTCP_MAX_GSO_SIZE (GSO_LEGACY_MAX_SIZE - (MAX_TCP_HEADER + 1))
1246
1247static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
1248 struct mptcp_data_frag *dfrag,
1249 struct mptcp_sendmsg_info *info)
1250{
1251 u64 data_seq = dfrag->data_seq + info->sent;
1252 int offset = dfrag->offset + info->sent;
1253 struct mptcp_sock *msk = mptcp_sk(sk);
1254 bool zero_window_probe = false;
1255 struct mptcp_ext *mpext = NULL;
1256 bool can_coalesce = false;
1257 bool reuse_skb = true;
1258 struct sk_buff *skb;
1259 size_t copy;
1260 int i;
1261
1262 pr_debug("msk=%p ssk=%p sending dfrag at seq=%llu len=%u already sent=%u\n",
1263 msk, ssk, dfrag->data_seq, dfrag->data_len, info->sent);
1264
1265 if (WARN_ON_ONCE(info->sent > info->limit ||
1266 info->limit > dfrag->data_len))
1267 return 0;
1268
1269 if (unlikely(!__tcp_can_send(ssk)))
1270 return -EAGAIN;
1271
1272 /* compute send limit */
1273 if (unlikely(ssk->sk_gso_max_size > MPTCP_MAX_GSO_SIZE))
1274 ssk->sk_gso_max_size = MPTCP_MAX_GSO_SIZE;
1275 info->mss_now = tcp_send_mss(ssk, &info->size_goal, info->flags);
1276 copy = info->size_goal;
1277
1278 skb = tcp_write_queue_tail(ssk);
1279 if (skb && copy > skb->len) {
1280 /* Limit the write to the size available in the
1281 * current skb, if any, so that we create at most a new skb.
1282 * Explicitly tells TCP internals to avoid collapsing on later
1283 * queue management operation, to avoid breaking the ext <->
1284 * SSN association set here
1285 */
1286 mpext = mptcp_get_ext(skb);
1287 if (!mptcp_skb_can_collapse_to(data_seq, skb, mpext)) {
1288 TCP_SKB_CB(skb)->eor = 1;
1289 tcp_mark_push(tcp_sk(ssk), skb);
1290 goto alloc_skb;
1291 }
1292
1293 i = skb_shinfo(skb)->nr_frags;
1294 can_coalesce = skb_can_coalesce(skb, i, dfrag->page, offset);
1295 if (!can_coalesce && i >= READ_ONCE(net_hotdata.sysctl_max_skb_frags)) {
1296 tcp_mark_push(tcp_sk(ssk), skb);
1297 goto alloc_skb;
1298 }
1299
1300 copy -= skb->len;
1301 } else {
1302alloc_skb:
1303 skb = mptcp_alloc_tx_skb(sk, ssk, info->data_lock_held);
1304 if (!skb)
1305 return -ENOMEM;
1306
1307 i = skb_shinfo(skb)->nr_frags;
1308 reuse_skb = false;
1309 mpext = mptcp_get_ext(skb);
1310 }
1311
1312 /* Zero window and all data acked? Probe. */
1313 copy = mptcp_check_allowed_size(msk, ssk, data_seq, copy);
1314 if (copy == 0) {
1315 u64 snd_una = READ_ONCE(msk->snd_una);
1316
1317 if (snd_una != msk->snd_nxt || tcp_write_queue_tail(ssk)) {
1318 tcp_remove_empty_skb(ssk);
1319 return 0;
1320 }
1321
1322 zero_window_probe = true;
1323 data_seq = snd_una - 1;
1324 copy = 1;
1325 }
1326
1327 copy = min_t(size_t, copy, info->limit - info->sent);
1328 if (!sk_wmem_schedule(ssk, copy)) {
1329 tcp_remove_empty_skb(ssk);
1330 return -ENOMEM;
1331 }
1332
1333 if (can_coalesce) {
1334 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1335 } else {
1336 get_page(dfrag->page);
1337 skb_fill_page_desc(skb, i, dfrag->page, offset, copy);
1338 }
1339
1340 skb->len += copy;
1341 skb->data_len += copy;
1342 skb->truesize += copy;
1343 sk_wmem_queued_add(ssk, copy);
1344 sk_mem_charge(ssk, copy);
1345 WRITE_ONCE(tcp_sk(ssk)->write_seq, tcp_sk(ssk)->write_seq + copy);
1346 TCP_SKB_CB(skb)->end_seq += copy;
1347 tcp_skb_pcount_set(skb, 0);
1348
1349 /* on skb reuse we just need to update the DSS len */
1350 if (reuse_skb) {
1351 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1352 mpext->data_len += copy;
1353 goto out;
1354 }
1355
1356 memset(mpext, 0, sizeof(*mpext));
1357 mpext->data_seq = data_seq;
1358 mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq;
1359 mpext->data_len = copy;
1360 mpext->use_map = 1;
1361 mpext->dsn64 = 1;
1362
1363 pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d\n",
1364 mpext->data_seq, mpext->subflow_seq, mpext->data_len,
1365 mpext->dsn64);
1366
1367 if (zero_window_probe) {
1368 mptcp_subflow_ctx(ssk)->rel_write_seq += copy;
1369 mpext->frozen = 1;
1370 if (READ_ONCE(msk->csum_enabled))
1371 mptcp_update_data_checksum(skb, copy);
1372 tcp_push_pending_frames(ssk);
1373 return 0;
1374 }
1375out:
1376 if (READ_ONCE(msk->csum_enabled))
1377 mptcp_update_data_checksum(skb, copy);
1378 if (mptcp_subflow_ctx(ssk)->send_infinite_map)
1379 mptcp_update_infinite_map(msk, ssk, mpext);
1380 trace_mptcp_sendmsg_frag(mpext);
1381 mptcp_subflow_ctx(ssk)->rel_write_seq += copy;
1382 return copy;
1383}
1384
1385#define MPTCP_SEND_BURST_SIZE ((1 << 16) - \
1386 sizeof(struct tcphdr) - \
1387 MAX_TCP_OPTION_SPACE - \
1388 sizeof(struct ipv6hdr) - \
1389 sizeof(struct frag_hdr))
1390
1391struct subflow_send_info {
1392 struct sock *ssk;
1393 u64 linger_time;
1394};
1395
1396void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow)
1397{
1398 if (!subflow->stale)
1399 return;
1400
1401 subflow->stale = 0;
1402 MPTCP_INC_STATS(sock_net(mptcp_subflow_tcp_sock(subflow)), MPTCP_MIB_SUBFLOWRECOVER);
1403}
1404
1405bool mptcp_subflow_active(struct mptcp_subflow_context *subflow)
1406{
1407 if (unlikely(subflow->stale)) {
1408 u32 rcv_tstamp = READ_ONCE(tcp_sk(mptcp_subflow_tcp_sock(subflow))->rcv_tstamp);
1409
1410 if (subflow->stale_rcv_tstamp == rcv_tstamp)
1411 return false;
1412
1413 mptcp_subflow_set_active(subflow);
1414 }
1415 return __mptcp_subflow_active(subflow);
1416}
1417
1418#define SSK_MODE_ACTIVE 0
1419#define SSK_MODE_BACKUP 1
1420#define SSK_MODE_MAX 2
1421
1422/* implement the mptcp packet scheduler;
1423 * returns the subflow that will transmit the next DSS
1424 * additionally updates the rtx timeout
1425 */
1426struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk)
1427{
1428 struct subflow_send_info send_info[SSK_MODE_MAX];
1429 struct mptcp_subflow_context *subflow;
1430 struct sock *sk = (struct sock *)msk;
1431 u32 pace, burst, wmem;
1432 int i, nr_active = 0;
1433 struct sock *ssk;
1434 u64 linger_time;
1435 long tout = 0;
1436
1437 /* pick the subflow with the lower wmem/wspace ratio */
1438 for (i = 0; i < SSK_MODE_MAX; ++i) {
1439 send_info[i].ssk = NULL;
1440 send_info[i].linger_time = -1;
1441 }
1442
1443 mptcp_for_each_subflow(msk, subflow) {
1444 bool backup = subflow->backup || subflow->request_bkup;
1445
1446 trace_mptcp_subflow_get_send(subflow);
1447 ssk = mptcp_subflow_tcp_sock(subflow);
1448 if (!mptcp_subflow_active(subflow))
1449 continue;
1450
1451 tout = max(tout, mptcp_timeout_from_subflow(subflow));
1452 nr_active += !backup;
1453 pace = subflow->avg_pacing_rate;
1454 if (unlikely(!pace)) {
1455 /* init pacing rate from socket */
1456 subflow->avg_pacing_rate = READ_ONCE(ssk->sk_pacing_rate);
1457 pace = subflow->avg_pacing_rate;
1458 if (!pace)
1459 continue;
1460 }
1461
1462 linger_time = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32, pace);
1463 if (linger_time < send_info[backup].linger_time) {
1464 send_info[backup].ssk = ssk;
1465 send_info[backup].linger_time = linger_time;
1466 }
1467 }
1468 __mptcp_set_timeout(sk, tout);
1469
1470 /* pick the best backup if no other subflow is active */
1471 if (!nr_active)
1472 send_info[SSK_MODE_ACTIVE].ssk = send_info[SSK_MODE_BACKUP].ssk;
1473
1474 /* According to the blest algorithm, to avoid HoL blocking for the
1475 * faster flow, we need to:
1476 * - estimate the faster flow linger time
1477 * - use the above to estimate the amount of byte transferred
1478 * by the faster flow
1479 * - check that the amount of queued data is greter than the above,
1480 * otherwise do not use the picked, slower, subflow
1481 * We select the subflow with the shorter estimated time to flush
1482 * the queued mem, which basically ensure the above. We just need
1483 * to check that subflow has a non empty cwin.
1484 */
1485 ssk = send_info[SSK_MODE_ACTIVE].ssk;
1486 if (!ssk || !sk_stream_memory_free(ssk))
1487 return NULL;
1488
1489 burst = min_t(int, MPTCP_SEND_BURST_SIZE, mptcp_wnd_end(msk) - msk->snd_nxt);
1490 wmem = READ_ONCE(ssk->sk_wmem_queued);
1491 if (!burst)
1492 return ssk;
1493
1494 subflow = mptcp_subflow_ctx(ssk);
1495 subflow->avg_pacing_rate = div_u64((u64)subflow->avg_pacing_rate * wmem +
1496 READ_ONCE(ssk->sk_pacing_rate) * burst,
1497 burst + wmem);
1498 msk->snd_burst = burst;
1499 return ssk;
1500}
1501
1502static void mptcp_push_release(struct sock *ssk, struct mptcp_sendmsg_info *info)
1503{
1504 tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal);
1505 release_sock(ssk);
1506}
1507
1508static void mptcp_update_post_push(struct mptcp_sock *msk,
1509 struct mptcp_data_frag *dfrag,
1510 u32 sent)
1511{
1512 u64 snd_nxt_new = dfrag->data_seq;
1513
1514 dfrag->already_sent += sent;
1515
1516 msk->snd_burst -= sent;
1517
1518 snd_nxt_new += dfrag->already_sent;
1519
1520 /* snd_nxt_new can be smaller than snd_nxt in case mptcp
1521 * is recovering after a failover. In that event, this re-sends
1522 * old segments.
1523 *
1524 * Thus compute snd_nxt_new candidate based on
1525 * the dfrag->data_seq that was sent and the data
1526 * that has been handed to the subflow for transmission
1527 * and skip update in case it was old dfrag.
1528 */
1529 if (likely(after64(snd_nxt_new, msk->snd_nxt))) {
1530 msk->bytes_sent += snd_nxt_new - msk->snd_nxt;
1531 WRITE_ONCE(msk->snd_nxt, snd_nxt_new);
1532 }
1533}
1534
1535void mptcp_check_and_set_pending(struct sock *sk)
1536{
1537 if (mptcp_send_head(sk)) {
1538 mptcp_data_lock(sk);
1539 mptcp_sk(sk)->cb_flags |= BIT(MPTCP_PUSH_PENDING);
1540 mptcp_data_unlock(sk);
1541 }
1542}
1543
1544static int __subflow_push_pending(struct sock *sk, struct sock *ssk,
1545 struct mptcp_sendmsg_info *info)
1546{
1547 struct mptcp_sock *msk = mptcp_sk(sk);
1548 struct mptcp_data_frag *dfrag;
1549 int len, copied = 0, err = 0;
1550
1551 while ((dfrag = mptcp_send_head(sk))) {
1552 info->sent = dfrag->already_sent;
1553 info->limit = dfrag->data_len;
1554 len = dfrag->data_len - dfrag->already_sent;
1555 while (len > 0) {
1556 int ret = 0;
1557
1558 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, info);
1559 if (ret <= 0) {
1560 err = copied ? : ret;
1561 goto out;
1562 }
1563
1564 info->sent += ret;
1565 copied += ret;
1566 len -= ret;
1567
1568 mptcp_update_post_push(msk, dfrag, ret);
1569 }
1570 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1571
1572 if (msk->snd_burst <= 0 ||
1573 !sk_stream_memory_free(ssk) ||
1574 !mptcp_subflow_active(mptcp_subflow_ctx(ssk))) {
1575 err = copied;
1576 goto out;
1577 }
1578 mptcp_set_timeout(sk);
1579 }
1580 err = copied;
1581
1582out:
1583 if (err > 0)
1584 msk->last_data_sent = tcp_jiffies32;
1585 return err;
1586}
1587
1588void __mptcp_push_pending(struct sock *sk, unsigned int flags)
1589{
1590 struct sock *prev_ssk = NULL, *ssk = NULL;
1591 struct mptcp_sock *msk = mptcp_sk(sk);
1592 struct mptcp_sendmsg_info info = {
1593 .flags = flags,
1594 };
1595 bool do_check_data_fin = false;
1596 int push_count = 1;
1597
1598 while (mptcp_send_head(sk) && (push_count > 0)) {
1599 struct mptcp_subflow_context *subflow;
1600 int ret = 0;
1601
1602 if (mptcp_sched_get_send(msk))
1603 break;
1604
1605 push_count = 0;
1606
1607 mptcp_for_each_subflow(msk, subflow) {
1608 if (READ_ONCE(subflow->scheduled)) {
1609 mptcp_subflow_set_scheduled(subflow, false);
1610
1611 prev_ssk = ssk;
1612 ssk = mptcp_subflow_tcp_sock(subflow);
1613 if (ssk != prev_ssk) {
1614 /* First check. If the ssk has changed since
1615 * the last round, release prev_ssk
1616 */
1617 if (prev_ssk)
1618 mptcp_push_release(prev_ssk, &info);
1619
1620 /* Need to lock the new subflow only if different
1621 * from the previous one, otherwise we are still
1622 * helding the relevant lock
1623 */
1624 lock_sock(ssk);
1625 }
1626
1627 push_count++;
1628
1629 ret = __subflow_push_pending(sk, ssk, &info);
1630 if (ret <= 0) {
1631 if (ret != -EAGAIN ||
1632 (1 << ssk->sk_state) &
1633 (TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSE))
1634 push_count--;
1635 continue;
1636 }
1637 do_check_data_fin = true;
1638 }
1639 }
1640 }
1641
1642 /* at this point we held the socket lock for the last subflow we used */
1643 if (ssk)
1644 mptcp_push_release(ssk, &info);
1645
1646 /* ensure the rtx timer is running */
1647 if (!mptcp_rtx_timer_pending(sk))
1648 mptcp_reset_rtx_timer(sk);
1649 if (do_check_data_fin)
1650 mptcp_check_send_data_fin(sk);
1651}
1652
1653static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk, bool first)
1654{
1655 struct mptcp_sock *msk = mptcp_sk(sk);
1656 struct mptcp_sendmsg_info info = {
1657 .data_lock_held = true,
1658 };
1659 bool keep_pushing = true;
1660 struct sock *xmit_ssk;
1661 int copied = 0;
1662
1663 info.flags = 0;
1664 while (mptcp_send_head(sk) && keep_pushing) {
1665 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1666 int ret = 0;
1667
1668 /* check for a different subflow usage only after
1669 * spooling the first chunk of data
1670 */
1671 if (first) {
1672 mptcp_subflow_set_scheduled(subflow, false);
1673 ret = __subflow_push_pending(sk, ssk, &info);
1674 first = false;
1675 if (ret <= 0)
1676 break;
1677 copied += ret;
1678 continue;
1679 }
1680
1681 if (mptcp_sched_get_send(msk))
1682 goto out;
1683
1684 if (READ_ONCE(subflow->scheduled)) {
1685 mptcp_subflow_set_scheduled(subflow, false);
1686 ret = __subflow_push_pending(sk, ssk, &info);
1687 if (ret <= 0)
1688 keep_pushing = false;
1689 copied += ret;
1690 }
1691
1692 mptcp_for_each_subflow(msk, subflow) {
1693 if (READ_ONCE(subflow->scheduled)) {
1694 xmit_ssk = mptcp_subflow_tcp_sock(subflow);
1695 if (xmit_ssk != ssk) {
1696 mptcp_subflow_delegate(subflow,
1697 MPTCP_DELEGATE_SEND);
1698 keep_pushing = false;
1699 }
1700 }
1701 }
1702 }
1703
1704out:
1705 /* __mptcp_alloc_tx_skb could have released some wmem and we are
1706 * not going to flush it via release_sock()
1707 */
1708 if (copied) {
1709 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
1710 info.size_goal);
1711 if (!mptcp_rtx_timer_pending(sk))
1712 mptcp_reset_rtx_timer(sk);
1713
1714 if (msk->snd_data_fin_enable &&
1715 msk->snd_nxt + 1 == msk->write_seq)
1716 mptcp_schedule_work(sk);
1717 }
1718}
1719
1720static int mptcp_disconnect(struct sock *sk, int flags);
1721
1722static int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
1723 size_t len, int *copied_syn)
1724{
1725 unsigned int saved_flags = msg->msg_flags;
1726 struct mptcp_sock *msk = mptcp_sk(sk);
1727 struct sock *ssk;
1728 int ret;
1729
1730 /* on flags based fastopen the mptcp is supposed to create the
1731 * first subflow right now. Otherwise we are in the defer_connect
1732 * path, and the first subflow must be already present.
1733 * Since the defer_connect flag is cleared after the first succsful
1734 * fastopen attempt, no need to check for additional subflow status.
1735 */
1736 if (msg->msg_flags & MSG_FASTOPEN) {
1737 ssk = __mptcp_nmpc_sk(msk);
1738 if (IS_ERR(ssk))
1739 return PTR_ERR(ssk);
1740 }
1741 if (!msk->first)
1742 return -EINVAL;
1743
1744 ssk = msk->first;
1745
1746 lock_sock(ssk);
1747 msg->msg_flags |= MSG_DONTWAIT;
1748 msk->fastopening = 1;
1749 ret = tcp_sendmsg_fastopen(ssk, msg, copied_syn, len, NULL);
1750 msk->fastopening = 0;
1751 msg->msg_flags = saved_flags;
1752 release_sock(ssk);
1753
1754 /* do the blocking bits of inet_stream_connect outside the ssk socket lock */
1755 if (ret == -EINPROGRESS && !(msg->msg_flags & MSG_DONTWAIT)) {
1756 ret = __inet_stream_connect(sk->sk_socket, msg->msg_name,
1757 msg->msg_namelen, msg->msg_flags, 1);
1758
1759 /* Keep the same behaviour of plain TCP: zero the copied bytes in
1760 * case of any error, except timeout or signal
1761 */
1762 if (ret && ret != -EINPROGRESS && ret != -ERESTARTSYS && ret != -EINTR)
1763 *copied_syn = 0;
1764 } else if (ret && ret != -EINPROGRESS) {
1765 /* The disconnect() op called by tcp_sendmsg_fastopen()/
1766 * __inet_stream_connect() can fail, due to looking check,
1767 * see mptcp_disconnect().
1768 * Attempt it again outside the problematic scope.
1769 */
1770 if (!mptcp_disconnect(sk, 0)) {
1771 sk->sk_disconnects++;
1772 sk->sk_socket->state = SS_UNCONNECTED;
1773 }
1774 }
1775 inet_clear_bit(DEFER_CONNECT, sk);
1776
1777 return ret;
1778}
1779
1780static int do_copy_data_nocache(struct sock *sk, int copy,
1781 struct iov_iter *from, char *to)
1782{
1783 if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) {
1784 if (!copy_from_iter_full_nocache(to, copy, from))
1785 return -EFAULT;
1786 } else if (!copy_from_iter_full(to, copy, from)) {
1787 return -EFAULT;
1788 }
1789 return 0;
1790}
1791
1792/* open-code sk_stream_memory_free() plus sent limit computation to
1793 * avoid indirect calls in fast-path.
1794 * Called under the msk socket lock, so we can avoid a bunch of ONCE
1795 * annotations.
1796 */
1797static u32 mptcp_send_limit(const struct sock *sk)
1798{
1799 const struct mptcp_sock *msk = mptcp_sk(sk);
1800 u32 limit, not_sent;
1801
1802 if (sk->sk_wmem_queued >= READ_ONCE(sk->sk_sndbuf))
1803 return 0;
1804
1805 limit = mptcp_notsent_lowat(sk);
1806 if (limit == UINT_MAX)
1807 return UINT_MAX;
1808
1809 not_sent = msk->write_seq - msk->snd_nxt;
1810 if (not_sent >= limit)
1811 return 0;
1812
1813 return limit - not_sent;
1814}
1815
1816static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
1817{
1818 struct mptcp_sock *msk = mptcp_sk(sk);
1819 struct page_frag *pfrag;
1820 size_t copied = 0;
1821 int ret = 0;
1822 long timeo;
1823
1824 /* silently ignore everything else */
1825 msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | MSG_FASTOPEN;
1826
1827 lock_sock(sk);
1828
1829 if (unlikely(inet_test_bit(DEFER_CONNECT, sk) ||
1830 msg->msg_flags & MSG_FASTOPEN)) {
1831 int copied_syn = 0;
1832
1833 ret = mptcp_sendmsg_fastopen(sk, msg, len, &copied_syn);
1834 copied += copied_syn;
1835 if (ret == -EINPROGRESS && copied_syn > 0)
1836 goto out;
1837 else if (ret)
1838 goto do_error;
1839 }
1840
1841 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1842
1843 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
1844 ret = sk_stream_wait_connect(sk, &timeo);
1845 if (ret)
1846 goto do_error;
1847 }
1848
1849 ret = -EPIPE;
1850 if (unlikely(sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)))
1851 goto do_error;
1852
1853 pfrag = sk_page_frag(sk);
1854
1855 while (msg_data_left(msg)) {
1856 int total_ts, frag_truesize = 0;
1857 struct mptcp_data_frag *dfrag;
1858 bool dfrag_collapsed;
1859 size_t psize, offset;
1860 u32 copy_limit;
1861
1862 /* ensure fitting the notsent_lowat() constraint */
1863 copy_limit = mptcp_send_limit(sk);
1864 if (!copy_limit)
1865 goto wait_for_memory;
1866
1867 /* reuse tail pfrag, if possible, or carve a new one from the
1868 * page allocator
1869 */
1870 dfrag = mptcp_pending_tail(sk);
1871 dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag);
1872 if (!dfrag_collapsed) {
1873 if (!mptcp_page_frag_refill(sk, pfrag))
1874 goto wait_for_memory;
1875
1876 dfrag = mptcp_carve_data_frag(msk, pfrag, pfrag->offset);
1877 frag_truesize = dfrag->overhead;
1878 }
1879
1880 /* we do not bound vs wspace, to allow a single packet.
1881 * memory accounting will prevent execessive memory usage
1882 * anyway
1883 */
1884 offset = dfrag->offset + dfrag->data_len;
1885 psize = pfrag->size - offset;
1886 psize = min_t(size_t, psize, msg_data_left(msg));
1887 psize = min_t(size_t, psize, copy_limit);
1888 total_ts = psize + frag_truesize;
1889
1890 if (!sk_wmem_schedule(sk, total_ts))
1891 goto wait_for_memory;
1892
1893 ret = do_copy_data_nocache(sk, psize, &msg->msg_iter,
1894 page_address(dfrag->page) + offset);
1895 if (ret)
1896 goto do_error;
1897
1898 /* data successfully copied into the write queue */
1899 sk_forward_alloc_add(sk, -total_ts);
1900 copied += psize;
1901 dfrag->data_len += psize;
1902 frag_truesize += psize;
1903 pfrag->offset += frag_truesize;
1904 WRITE_ONCE(msk->write_seq, msk->write_seq + psize);
1905
1906 /* charge data on mptcp pending queue to the msk socket
1907 * Note: we charge such data both to sk and ssk
1908 */
1909 sk_wmem_queued_add(sk, frag_truesize);
1910 if (!dfrag_collapsed) {
1911 get_page(dfrag->page);
1912 list_add_tail(&dfrag->list, &msk->rtx_queue);
1913 if (!msk->first_pending)
1914 WRITE_ONCE(msk->first_pending, dfrag);
1915 }
1916 pr_debug("msk=%p dfrag at seq=%llu len=%u sent=%u new=%d\n", msk,
1917 dfrag->data_seq, dfrag->data_len, dfrag->already_sent,
1918 !dfrag_collapsed);
1919
1920 continue;
1921
1922wait_for_memory:
1923 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1924 __mptcp_push_pending(sk, msg->msg_flags);
1925 ret = sk_stream_wait_memory(sk, &timeo);
1926 if (ret)
1927 goto do_error;
1928 }
1929
1930 if (copied)
1931 __mptcp_push_pending(sk, msg->msg_flags);
1932
1933out:
1934 release_sock(sk);
1935 return copied;
1936
1937do_error:
1938 if (copied)
1939 goto out;
1940
1941 copied = sk_stream_error(sk, msg->msg_flags, ret);
1942 goto out;
1943}
1944
1945static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied);
1946
1947static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk,
1948 struct msghdr *msg,
1949 size_t len, int flags,
1950 struct scm_timestamping_internal *tss,
1951 int *cmsg_flags)
1952{
1953 struct sk_buff *skb, *tmp;
1954 int copied = 0;
1955
1956 skb_queue_walk_safe(&msk->receive_queue, skb, tmp) {
1957 u32 offset = MPTCP_SKB_CB(skb)->offset;
1958 u32 data_len = skb->len - offset;
1959 u32 count = min_t(size_t, len - copied, data_len);
1960 int err;
1961
1962 if (!(flags & MSG_TRUNC)) {
1963 err = skb_copy_datagram_msg(skb, offset, msg, count);
1964 if (unlikely(err < 0)) {
1965 if (!copied)
1966 return err;
1967 break;
1968 }
1969 }
1970
1971 if (MPTCP_SKB_CB(skb)->has_rxtstamp) {
1972 tcp_update_recv_tstamps(skb, tss);
1973 *cmsg_flags |= MPTCP_CMSG_TS;
1974 }
1975
1976 copied += count;
1977
1978 if (count < data_len) {
1979 if (!(flags & MSG_PEEK)) {
1980 MPTCP_SKB_CB(skb)->offset += count;
1981 MPTCP_SKB_CB(skb)->map_seq += count;
1982 msk->bytes_consumed += count;
1983 }
1984 break;
1985 }
1986
1987 if (!(flags & MSG_PEEK)) {
1988 /* we will bulk release the skb memory later */
1989 skb->destructor = NULL;
1990 WRITE_ONCE(msk->rmem_released, msk->rmem_released + skb->truesize);
1991 __skb_unlink(skb, &msk->receive_queue);
1992 __kfree_skb(skb);
1993 msk->bytes_consumed += count;
1994 }
1995
1996 if (copied >= len)
1997 break;
1998 }
1999
2000 mptcp_rcv_space_adjust(msk, copied);
2001 return copied;
2002}
2003
2004/* receive buffer autotuning. See tcp_rcv_space_adjust for more information.
2005 *
2006 * Only difference: Use highest rtt estimate of the subflows in use.
2007 */
2008static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied)
2009{
2010 struct mptcp_subflow_context *subflow;
2011 struct sock *sk = (struct sock *)msk;
2012 u8 scaling_ratio = U8_MAX;
2013 u32 time, advmss = 1;
2014 u64 rtt_us, mstamp;
2015
2016 msk_owned_by_me(msk);
2017
2018 if (copied <= 0)
2019 return;
2020
2021 if (!msk->rcvspace_init)
2022 mptcp_rcv_space_init(msk, msk->first);
2023
2024 msk->rcvq_space.copied += copied;
2025
2026 mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC);
2027 time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time);
2028
2029 rtt_us = msk->rcvq_space.rtt_us;
2030 if (rtt_us && time < (rtt_us >> 3))
2031 return;
2032
2033 rtt_us = 0;
2034 mptcp_for_each_subflow(msk, subflow) {
2035 const struct tcp_sock *tp;
2036 u64 sf_rtt_us;
2037 u32 sf_advmss;
2038
2039 tp = tcp_sk(mptcp_subflow_tcp_sock(subflow));
2040
2041 sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us);
2042 sf_advmss = READ_ONCE(tp->advmss);
2043
2044 rtt_us = max(sf_rtt_us, rtt_us);
2045 advmss = max(sf_advmss, advmss);
2046 scaling_ratio = min(tp->scaling_ratio, scaling_ratio);
2047 }
2048
2049 msk->rcvq_space.rtt_us = rtt_us;
2050 msk->scaling_ratio = scaling_ratio;
2051 if (time < (rtt_us >> 3) || rtt_us == 0)
2052 return;
2053
2054 if (msk->rcvq_space.copied <= msk->rcvq_space.space)
2055 goto new_measure;
2056
2057 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf) &&
2058 !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
2059 u64 rcvwin, grow;
2060 int rcvbuf;
2061
2062 rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss;
2063
2064 grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space);
2065
2066 do_div(grow, msk->rcvq_space.space);
2067 rcvwin += (grow << 1);
2068
2069 rcvbuf = min_t(u64, mptcp_space_from_win(sk, rcvwin),
2070 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[2]));
2071
2072 if (rcvbuf > sk->sk_rcvbuf) {
2073 u32 window_clamp;
2074
2075 window_clamp = mptcp_win_from_space(sk, rcvbuf);
2076 WRITE_ONCE(sk->sk_rcvbuf, rcvbuf);
2077
2078 /* Make subflows follow along. If we do not do this, we
2079 * get drops at subflow level if skbs can't be moved to
2080 * the mptcp rx queue fast enough (announced rcv_win can
2081 * exceed ssk->sk_rcvbuf).
2082 */
2083 mptcp_for_each_subflow(msk, subflow) {
2084 struct sock *ssk;
2085 bool slow;
2086
2087 ssk = mptcp_subflow_tcp_sock(subflow);
2088 slow = lock_sock_fast(ssk);
2089 WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf);
2090 WRITE_ONCE(tcp_sk(ssk)->window_clamp, window_clamp);
2091 if (tcp_can_send_ack(ssk))
2092 tcp_cleanup_rbuf(ssk, 1);
2093 unlock_sock_fast(ssk, slow);
2094 }
2095 }
2096 }
2097
2098 msk->rcvq_space.space = msk->rcvq_space.copied;
2099new_measure:
2100 msk->rcvq_space.copied = 0;
2101 msk->rcvq_space.time = mstamp;
2102}
2103
2104static void __mptcp_update_rmem(struct sock *sk)
2105{
2106 struct mptcp_sock *msk = mptcp_sk(sk);
2107
2108 if (!msk->rmem_released)
2109 return;
2110
2111 atomic_sub(msk->rmem_released, &sk->sk_rmem_alloc);
2112 mptcp_rmem_uncharge(sk, msk->rmem_released);
2113 WRITE_ONCE(msk->rmem_released, 0);
2114}
2115
2116static void __mptcp_splice_receive_queue(struct sock *sk)
2117{
2118 struct mptcp_sock *msk = mptcp_sk(sk);
2119
2120 skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue);
2121}
2122
2123static bool __mptcp_move_skbs(struct mptcp_sock *msk)
2124{
2125 struct sock *sk = (struct sock *)msk;
2126 unsigned int moved = 0;
2127 bool ret, done;
2128
2129 do {
2130 struct sock *ssk = mptcp_subflow_recv_lookup(msk);
2131 bool slowpath;
2132
2133 /* we can have data pending in the subflows only if the msk
2134 * receive buffer was full at subflow_data_ready() time,
2135 * that is an unlikely slow path.
2136 */
2137 if (likely(!ssk))
2138 break;
2139
2140 slowpath = lock_sock_fast(ssk);
2141 mptcp_data_lock(sk);
2142 __mptcp_update_rmem(sk);
2143 done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
2144 mptcp_data_unlock(sk);
2145
2146 if (unlikely(ssk->sk_err))
2147 __mptcp_error_report(sk);
2148 unlock_sock_fast(ssk, slowpath);
2149 } while (!done);
2150
2151 /* acquire the data lock only if some input data is pending */
2152 ret = moved > 0;
2153 if (!RB_EMPTY_ROOT(&msk->out_of_order_queue) ||
2154 !skb_queue_empty_lockless(&sk->sk_receive_queue)) {
2155 mptcp_data_lock(sk);
2156 __mptcp_update_rmem(sk);
2157 ret |= __mptcp_ofo_queue(msk);
2158 __mptcp_splice_receive_queue(sk);
2159 mptcp_data_unlock(sk);
2160 }
2161 if (ret)
2162 mptcp_check_data_fin((struct sock *)msk);
2163 return !skb_queue_empty(&msk->receive_queue);
2164}
2165
2166static unsigned int mptcp_inq_hint(const struct sock *sk)
2167{
2168 const struct mptcp_sock *msk = mptcp_sk(sk);
2169 const struct sk_buff *skb;
2170
2171 skb = skb_peek(&msk->receive_queue);
2172 if (skb) {
2173 u64 hint_val = READ_ONCE(msk->ack_seq) - MPTCP_SKB_CB(skb)->map_seq;
2174
2175 if (hint_val >= INT_MAX)
2176 return INT_MAX;
2177
2178 return (unsigned int)hint_val;
2179 }
2180
2181 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
2182 return 1;
2183
2184 return 0;
2185}
2186
2187static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
2188 int flags, int *addr_len)
2189{
2190 struct mptcp_sock *msk = mptcp_sk(sk);
2191 struct scm_timestamping_internal tss;
2192 int copied = 0, cmsg_flags = 0;
2193 int target;
2194 long timeo;
2195
2196 /* MSG_ERRQUEUE is really a no-op till we support IP_RECVERR */
2197 if (unlikely(flags & MSG_ERRQUEUE))
2198 return inet_recv_error(sk, msg, len, addr_len);
2199
2200 lock_sock(sk);
2201 if (unlikely(sk->sk_state == TCP_LISTEN)) {
2202 copied = -ENOTCONN;
2203 goto out_err;
2204 }
2205
2206 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2207
2208 len = min_t(size_t, len, INT_MAX);
2209 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
2210
2211 if (unlikely(msk->recvmsg_inq))
2212 cmsg_flags = MPTCP_CMSG_INQ;
2213
2214 while (copied < len) {
2215 int err, bytes_read;
2216
2217 bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags, &tss, &cmsg_flags);
2218 if (unlikely(bytes_read < 0)) {
2219 if (!copied)
2220 copied = bytes_read;
2221 goto out_err;
2222 }
2223
2224 copied += bytes_read;
2225
2226 if (skb_queue_empty(&msk->receive_queue) && __mptcp_move_skbs(msk))
2227 continue;
2228
2229 /* only the MPTCP socket status is relevant here. The exit
2230 * conditions mirror closely tcp_recvmsg()
2231 */
2232 if (copied >= target)
2233 break;
2234
2235 if (copied) {
2236 if (sk->sk_err ||
2237 sk->sk_state == TCP_CLOSE ||
2238 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2239 !timeo ||
2240 signal_pending(current))
2241 break;
2242 } else {
2243 if (sk->sk_err) {
2244 copied = sock_error(sk);
2245 break;
2246 }
2247
2248 if (sk->sk_shutdown & RCV_SHUTDOWN) {
2249 /* race breaker: the shutdown could be after the
2250 * previous receive queue check
2251 */
2252 if (__mptcp_move_skbs(msk))
2253 continue;
2254 break;
2255 }
2256
2257 if (sk->sk_state == TCP_CLOSE) {
2258 copied = -ENOTCONN;
2259 break;
2260 }
2261
2262 if (!timeo) {
2263 copied = -EAGAIN;
2264 break;
2265 }
2266
2267 if (signal_pending(current)) {
2268 copied = sock_intr_errno(timeo);
2269 break;
2270 }
2271 }
2272
2273 pr_debug("block timeout %ld\n", timeo);
2274 mptcp_cleanup_rbuf(msk, copied);
2275 err = sk_wait_data(sk, &timeo, NULL);
2276 if (err < 0) {
2277 err = copied ? : err;
2278 goto out_err;
2279 }
2280 }
2281
2282 mptcp_cleanup_rbuf(msk, copied);
2283
2284out_err:
2285 if (cmsg_flags && copied >= 0) {
2286 if (cmsg_flags & MPTCP_CMSG_TS)
2287 tcp_recv_timestamp(msg, sk, &tss);
2288
2289 if (cmsg_flags & MPTCP_CMSG_INQ) {
2290 unsigned int inq = mptcp_inq_hint(sk);
2291
2292 put_cmsg(msg, SOL_TCP, TCP_CM_INQ, sizeof(inq), &inq);
2293 }
2294 }
2295
2296 pr_debug("msk=%p rx queue empty=%d:%d copied=%d\n",
2297 msk, skb_queue_empty_lockless(&sk->sk_receive_queue),
2298 skb_queue_empty(&msk->receive_queue), copied);
2299
2300 release_sock(sk);
2301 return copied;
2302}
2303
2304static void mptcp_retransmit_timer(struct timer_list *t)
2305{
2306 struct inet_connection_sock *icsk = from_timer(icsk, t,
2307 icsk_retransmit_timer);
2308 struct sock *sk = &icsk->icsk_inet.sk;
2309 struct mptcp_sock *msk = mptcp_sk(sk);
2310
2311 bh_lock_sock(sk);
2312 if (!sock_owned_by_user(sk)) {
2313 /* we need a process context to retransmit */
2314 if (!test_and_set_bit(MPTCP_WORK_RTX, &msk->flags))
2315 mptcp_schedule_work(sk);
2316 } else {
2317 /* delegate our work to tcp_release_cb() */
2318 __set_bit(MPTCP_RETRANSMIT, &msk->cb_flags);
2319 }
2320 bh_unlock_sock(sk);
2321 sock_put(sk);
2322}
2323
2324static void mptcp_tout_timer(struct timer_list *t)
2325{
2326 struct sock *sk = from_timer(sk, t, sk_timer);
2327
2328 mptcp_schedule_work(sk);
2329 sock_put(sk);
2330}
2331
2332/* Find an idle subflow. Return NULL if there is unacked data at tcp
2333 * level.
2334 *
2335 * A backup subflow is returned only if that is the only kind available.
2336 */
2337struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk)
2338{
2339 struct sock *backup = NULL, *pick = NULL;
2340 struct mptcp_subflow_context *subflow;
2341 int min_stale_count = INT_MAX;
2342
2343 mptcp_for_each_subflow(msk, subflow) {
2344 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2345
2346 if (!__mptcp_subflow_active(subflow))
2347 continue;
2348
2349 /* still data outstanding at TCP level? skip this */
2350 if (!tcp_rtx_and_write_queues_empty(ssk)) {
2351 mptcp_pm_subflow_chk_stale(msk, ssk);
2352 min_stale_count = min_t(int, min_stale_count, subflow->stale_count);
2353 continue;
2354 }
2355
2356 if (subflow->backup || subflow->request_bkup) {
2357 if (!backup)
2358 backup = ssk;
2359 continue;
2360 }
2361
2362 if (!pick)
2363 pick = ssk;
2364 }
2365
2366 if (pick)
2367 return pick;
2368
2369 /* use backup only if there are no progresses anywhere */
2370 return min_stale_count > 1 ? backup : NULL;
2371}
2372
2373bool __mptcp_retransmit_pending_data(struct sock *sk)
2374{
2375 struct mptcp_data_frag *cur, *rtx_head;
2376 struct mptcp_sock *msk = mptcp_sk(sk);
2377
2378 if (__mptcp_check_fallback(msk))
2379 return false;
2380
2381 /* the closing socket has some data untransmitted and/or unacked:
2382 * some data in the mptcp rtx queue has not really xmitted yet.
2383 * keep it simple and re-inject the whole mptcp level rtx queue
2384 */
2385 mptcp_data_lock(sk);
2386 __mptcp_clean_una_wakeup(sk);
2387 rtx_head = mptcp_rtx_head(sk);
2388 if (!rtx_head) {
2389 mptcp_data_unlock(sk);
2390 return false;
2391 }
2392
2393 msk->recovery_snd_nxt = msk->snd_nxt;
2394 msk->recovery = true;
2395 mptcp_data_unlock(sk);
2396
2397 msk->first_pending = rtx_head;
2398 msk->snd_burst = 0;
2399
2400 /* be sure to clear the "sent status" on all re-injected fragments */
2401 list_for_each_entry(cur, &msk->rtx_queue, list) {
2402 if (!cur->already_sent)
2403 break;
2404 cur->already_sent = 0;
2405 }
2406
2407 return true;
2408}
2409
2410/* flags for __mptcp_close_ssk() */
2411#define MPTCP_CF_PUSH BIT(1)
2412#define MPTCP_CF_FASTCLOSE BIT(2)
2413
2414/* be sure to send a reset only if the caller asked for it, also
2415 * clean completely the subflow status when the subflow reaches
2416 * TCP_CLOSE state
2417 */
2418static void __mptcp_subflow_disconnect(struct sock *ssk,
2419 struct mptcp_subflow_context *subflow,
2420 unsigned int flags)
2421{
2422 if (((1 << ssk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) ||
2423 (flags & MPTCP_CF_FASTCLOSE)) {
2424 /* The MPTCP code never wait on the subflow sockets, TCP-level
2425 * disconnect should never fail
2426 */
2427 WARN_ON_ONCE(tcp_disconnect(ssk, 0));
2428 mptcp_subflow_ctx_reset(subflow);
2429 } else {
2430 tcp_shutdown(ssk, SEND_SHUTDOWN);
2431 }
2432}
2433
2434/* subflow sockets can be either outgoing (connect) or incoming
2435 * (accept).
2436 *
2437 * Outgoing subflows use in-kernel sockets.
2438 * Incoming subflows do not have their own 'struct socket' allocated,
2439 * so we need to use tcp_close() after detaching them from the mptcp
2440 * parent socket.
2441 */
2442static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
2443 struct mptcp_subflow_context *subflow,
2444 unsigned int flags)
2445{
2446 struct mptcp_sock *msk = mptcp_sk(sk);
2447 bool dispose_it, need_push = false;
2448
2449 /* If the first subflow moved to a close state before accept, e.g. due
2450 * to an incoming reset or listener shutdown, the subflow socket is
2451 * already deleted by inet_child_forget() and the mptcp socket can't
2452 * survive too.
2453 */
2454 if (msk->in_accept_queue && msk->first == ssk &&
2455 (sock_flag(sk, SOCK_DEAD) || sock_flag(ssk, SOCK_DEAD))) {
2456 /* ensure later check in mptcp_worker() will dispose the msk */
2457 sock_set_flag(sk, SOCK_DEAD);
2458 mptcp_set_close_tout(sk, tcp_jiffies32 - (mptcp_close_timeout(sk) + 1));
2459 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
2460 mptcp_subflow_drop_ctx(ssk);
2461 goto out_release;
2462 }
2463
2464 dispose_it = msk->free_first || ssk != msk->first;
2465 if (dispose_it)
2466 list_del(&subflow->node);
2467
2468 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
2469
2470 if ((flags & MPTCP_CF_FASTCLOSE) && !__mptcp_check_fallback(msk)) {
2471 /* be sure to force the tcp_close path
2472 * to generate the egress reset
2473 */
2474 ssk->sk_lingertime = 0;
2475 sock_set_flag(ssk, SOCK_LINGER);
2476 subflow->send_fastclose = 1;
2477 }
2478
2479 need_push = (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(sk);
2480 if (!dispose_it) {
2481 __mptcp_subflow_disconnect(ssk, subflow, flags);
2482 release_sock(ssk);
2483
2484 goto out;
2485 }
2486
2487 subflow->disposable = 1;
2488
2489 /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops
2490 * the ssk has been already destroyed, we just need to release the
2491 * reference owned by msk;
2492 */
2493 if (!inet_csk(ssk)->icsk_ulp_ops) {
2494 WARN_ON_ONCE(!sock_flag(ssk, SOCK_DEAD));
2495 kfree_rcu(subflow, rcu);
2496 } else {
2497 /* otherwise tcp will dispose of the ssk and subflow ctx */
2498 __tcp_close(ssk, 0);
2499
2500 /* close acquired an extra ref */
2501 __sock_put(ssk);
2502 }
2503
2504out_release:
2505 __mptcp_subflow_error_report(sk, ssk);
2506 release_sock(ssk);
2507
2508 sock_put(ssk);
2509
2510 if (ssk == msk->first)
2511 WRITE_ONCE(msk->first, NULL);
2512
2513out:
2514 __mptcp_sync_sndbuf(sk);
2515 if (need_push)
2516 __mptcp_push_pending(sk, 0);
2517
2518 /* Catch every 'all subflows closed' scenario, including peers silently
2519 * closing them, e.g. due to timeout.
2520 * For established sockets, allow an additional timeout before closing,
2521 * as the protocol can still create more subflows.
2522 */
2523 if (list_is_singular(&msk->conn_list) && msk->first &&
2524 inet_sk_state_load(msk->first) == TCP_CLOSE) {
2525 if (sk->sk_state != TCP_ESTABLISHED ||
2526 msk->in_accept_queue || sock_flag(sk, SOCK_DEAD)) {
2527 mptcp_set_state(sk, TCP_CLOSE);
2528 mptcp_close_wake_up(sk);
2529 } else {
2530 mptcp_start_tout_timer(sk);
2531 }
2532 }
2533}
2534
2535void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
2536 struct mptcp_subflow_context *subflow)
2537{
2538 /* The first subflow can already be closed and still in the list */
2539 if (subflow->close_event_done)
2540 return;
2541
2542 subflow->close_event_done = true;
2543
2544 if (sk->sk_state == TCP_ESTABLISHED)
2545 mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL);
2546
2547 /* subflow aborted before reaching the fully_established status
2548 * attempt the creation of the next subflow
2549 */
2550 mptcp_pm_subflow_check_next(mptcp_sk(sk), subflow);
2551
2552 __mptcp_close_ssk(sk, ssk, subflow, MPTCP_CF_PUSH);
2553}
2554
2555static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu)
2556{
2557 return 0;
2558}
2559
2560static void __mptcp_close_subflow(struct sock *sk)
2561{
2562 struct mptcp_subflow_context *subflow, *tmp;
2563 struct mptcp_sock *msk = mptcp_sk(sk);
2564
2565 might_sleep();
2566
2567 mptcp_for_each_subflow_safe(msk, subflow, tmp) {
2568 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2569 int ssk_state = inet_sk_state_load(ssk);
2570
2571 if (ssk_state != TCP_CLOSE &&
2572 (ssk_state != TCP_CLOSE_WAIT ||
2573 inet_sk_state_load(sk) != TCP_ESTABLISHED))
2574 continue;
2575
2576 /* 'subflow_data_ready' will re-sched once rx queue is empty */
2577 if (!skb_queue_empty_lockless(&ssk->sk_receive_queue))
2578 continue;
2579
2580 mptcp_close_ssk(sk, ssk, subflow);
2581 }
2582
2583}
2584
2585static bool mptcp_close_tout_expired(const struct sock *sk)
2586{
2587 if (!inet_csk(sk)->icsk_mtup.probe_timestamp ||
2588 sk->sk_state == TCP_CLOSE)
2589 return false;
2590
2591 return time_after32(tcp_jiffies32,
2592 inet_csk(sk)->icsk_mtup.probe_timestamp + mptcp_close_timeout(sk));
2593}
2594
2595static void mptcp_check_fastclose(struct mptcp_sock *msk)
2596{
2597 struct mptcp_subflow_context *subflow, *tmp;
2598 struct sock *sk = (struct sock *)msk;
2599
2600 if (likely(!READ_ONCE(msk->rcv_fastclose)))
2601 return;
2602
2603 mptcp_token_destroy(msk);
2604
2605 mptcp_for_each_subflow_safe(msk, subflow, tmp) {
2606 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
2607 bool slow;
2608
2609 slow = lock_sock_fast(tcp_sk);
2610 if (tcp_sk->sk_state != TCP_CLOSE) {
2611 mptcp_send_active_reset_reason(tcp_sk);
2612 tcp_set_state(tcp_sk, TCP_CLOSE);
2613 }
2614 unlock_sock_fast(tcp_sk, slow);
2615 }
2616
2617 /* Mirror the tcp_reset() error propagation */
2618 switch (sk->sk_state) {
2619 case TCP_SYN_SENT:
2620 WRITE_ONCE(sk->sk_err, ECONNREFUSED);
2621 break;
2622 case TCP_CLOSE_WAIT:
2623 WRITE_ONCE(sk->sk_err, EPIPE);
2624 break;
2625 case TCP_CLOSE:
2626 return;
2627 default:
2628 WRITE_ONCE(sk->sk_err, ECONNRESET);
2629 }
2630
2631 mptcp_set_state(sk, TCP_CLOSE);
2632 WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
2633 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
2634 set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags);
2635
2636 /* the calling mptcp_worker will properly destroy the socket */
2637 if (sock_flag(sk, SOCK_DEAD))
2638 return;
2639
2640 sk->sk_state_change(sk);
2641 sk_error_report(sk);
2642}
2643
2644static void __mptcp_retrans(struct sock *sk)
2645{
2646 struct mptcp_sock *msk = mptcp_sk(sk);
2647 struct mptcp_subflow_context *subflow;
2648 struct mptcp_sendmsg_info info = {};
2649 struct mptcp_data_frag *dfrag;
2650 struct sock *ssk;
2651 int ret, err;
2652 u16 len = 0;
2653
2654 mptcp_clean_una_wakeup(sk);
2655
2656 /* first check ssk: need to kick "stale" logic */
2657 err = mptcp_sched_get_retrans(msk);
2658 dfrag = mptcp_rtx_head(sk);
2659 if (!dfrag) {
2660 if (mptcp_data_fin_enabled(msk)) {
2661 struct inet_connection_sock *icsk = inet_csk(sk);
2662
2663 icsk->icsk_retransmits++;
2664 mptcp_set_datafin_timeout(sk);
2665 mptcp_send_ack(msk);
2666
2667 goto reset_timer;
2668 }
2669
2670 if (!mptcp_send_head(sk))
2671 return;
2672
2673 goto reset_timer;
2674 }
2675
2676 if (err)
2677 goto reset_timer;
2678
2679 mptcp_for_each_subflow(msk, subflow) {
2680 if (READ_ONCE(subflow->scheduled)) {
2681 u16 copied = 0;
2682
2683 mptcp_subflow_set_scheduled(subflow, false);
2684
2685 ssk = mptcp_subflow_tcp_sock(subflow);
2686
2687 lock_sock(ssk);
2688
2689 /* limit retransmission to the bytes already sent on some subflows */
2690 info.sent = 0;
2691 info.limit = READ_ONCE(msk->csum_enabled) ? dfrag->data_len :
2692 dfrag->already_sent;
2693 while (info.sent < info.limit) {
2694 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
2695 if (ret <= 0)
2696 break;
2697
2698 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS);
2699 copied += ret;
2700 info.sent += ret;
2701 }
2702 if (copied) {
2703 len = max(copied, len);
2704 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
2705 info.size_goal);
2706 WRITE_ONCE(msk->allow_infinite_fallback, false);
2707 }
2708
2709 release_sock(ssk);
2710 }
2711 }
2712
2713 msk->bytes_retrans += len;
2714 dfrag->already_sent = max(dfrag->already_sent, len);
2715
2716reset_timer:
2717 mptcp_check_and_set_pending(sk);
2718
2719 if (!mptcp_rtx_timer_pending(sk))
2720 mptcp_reset_rtx_timer(sk);
2721}
2722
2723/* schedule the timeout timer for the relevant event: either close timeout
2724 * or mp_fail timeout. The close timeout takes precedence on the mp_fail one
2725 */
2726void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout)
2727{
2728 struct sock *sk = (struct sock *)msk;
2729 unsigned long timeout, close_timeout;
2730
2731 if (!fail_tout && !inet_csk(sk)->icsk_mtup.probe_timestamp)
2732 return;
2733
2734 close_timeout = (unsigned long)inet_csk(sk)->icsk_mtup.probe_timestamp -
2735 tcp_jiffies32 + jiffies + mptcp_close_timeout(sk);
2736
2737 /* the close timeout takes precedence on the fail one, and here at least one of
2738 * them is active
2739 */
2740 timeout = inet_csk(sk)->icsk_mtup.probe_timestamp ? close_timeout : fail_tout;
2741
2742 sk_reset_timer(sk, &sk->sk_timer, timeout);
2743}
2744
2745static void mptcp_mp_fail_no_response(struct mptcp_sock *msk)
2746{
2747 struct sock *ssk = msk->first;
2748 bool slow;
2749
2750 if (!ssk)
2751 return;
2752
2753 pr_debug("MP_FAIL doesn't respond, reset the subflow\n");
2754
2755 slow = lock_sock_fast(ssk);
2756 mptcp_subflow_reset(ssk);
2757 WRITE_ONCE(mptcp_subflow_ctx(ssk)->fail_tout, 0);
2758 unlock_sock_fast(ssk, slow);
2759}
2760
2761static void mptcp_do_fastclose(struct sock *sk)
2762{
2763 struct mptcp_subflow_context *subflow, *tmp;
2764 struct mptcp_sock *msk = mptcp_sk(sk);
2765
2766 mptcp_set_state(sk, TCP_CLOSE);
2767 mptcp_for_each_subflow_safe(msk, subflow, tmp)
2768 __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow),
2769 subflow, MPTCP_CF_FASTCLOSE);
2770}
2771
2772static void mptcp_worker(struct work_struct *work)
2773{
2774 struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
2775 struct sock *sk = (struct sock *)msk;
2776 unsigned long fail_tout;
2777 int state;
2778
2779 lock_sock(sk);
2780 state = sk->sk_state;
2781 if (unlikely((1 << state) & (TCPF_CLOSE | TCPF_LISTEN)))
2782 goto unlock;
2783
2784 mptcp_check_fastclose(msk);
2785
2786 mptcp_pm_nl_work(msk);
2787
2788 mptcp_check_send_data_fin(sk);
2789 mptcp_check_data_fin_ack(sk);
2790 mptcp_check_data_fin(sk);
2791
2792 if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
2793 __mptcp_close_subflow(sk);
2794
2795 if (mptcp_close_tout_expired(sk)) {
2796 mptcp_do_fastclose(sk);
2797 mptcp_close_wake_up(sk);
2798 }
2799
2800 if (sock_flag(sk, SOCK_DEAD) && sk->sk_state == TCP_CLOSE) {
2801 __mptcp_destroy_sock(sk);
2802 goto unlock;
2803 }
2804
2805 if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
2806 __mptcp_retrans(sk);
2807
2808 fail_tout = msk->first ? READ_ONCE(mptcp_subflow_ctx(msk->first)->fail_tout) : 0;
2809 if (fail_tout && time_after(jiffies, fail_tout))
2810 mptcp_mp_fail_no_response(msk);
2811
2812unlock:
2813 release_sock(sk);
2814 sock_put(sk);
2815}
2816
2817static void __mptcp_init_sock(struct sock *sk)
2818{
2819 struct mptcp_sock *msk = mptcp_sk(sk);
2820
2821 INIT_LIST_HEAD(&msk->conn_list);
2822 INIT_LIST_HEAD(&msk->join_list);
2823 INIT_LIST_HEAD(&msk->rtx_queue);
2824 INIT_WORK(&msk->work, mptcp_worker);
2825 __skb_queue_head_init(&msk->receive_queue);
2826 msk->out_of_order_queue = RB_ROOT;
2827 msk->first_pending = NULL;
2828 WRITE_ONCE(msk->rmem_fwd_alloc, 0);
2829 WRITE_ONCE(msk->rmem_released, 0);
2830 msk->timer_ival = TCP_RTO_MIN;
2831 msk->scaling_ratio = TCP_DEFAULT_SCALING_RATIO;
2832
2833 WRITE_ONCE(msk->first, NULL);
2834 inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss;
2835 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
2836 WRITE_ONCE(msk->allow_infinite_fallback, true);
2837 msk->recovery = false;
2838 msk->subflow_id = 1;
2839 msk->last_data_sent = tcp_jiffies32;
2840 msk->last_data_recv = tcp_jiffies32;
2841 msk->last_ack_recv = tcp_jiffies32;
2842
2843 mptcp_pm_data_init(msk);
2844
2845 /* re-use the csk retrans timer for MPTCP-level retrans */
2846 timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0);
2847 timer_setup(&sk->sk_timer, mptcp_tout_timer, 0);
2848}
2849
2850static void mptcp_ca_reset(struct sock *sk)
2851{
2852 struct inet_connection_sock *icsk = inet_csk(sk);
2853
2854 tcp_assign_congestion_control(sk);
2855 strscpy(mptcp_sk(sk)->ca_name, icsk->icsk_ca_ops->name,
2856 sizeof(mptcp_sk(sk)->ca_name));
2857
2858 /* no need to keep a reference to the ops, the name will suffice */
2859 tcp_cleanup_congestion_control(sk);
2860 icsk->icsk_ca_ops = NULL;
2861}
2862
2863static int mptcp_init_sock(struct sock *sk)
2864{
2865 struct net *net = sock_net(sk);
2866 int ret;
2867
2868 __mptcp_init_sock(sk);
2869
2870 if (!mptcp_is_enabled(net))
2871 return -ENOPROTOOPT;
2872
2873 if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net))
2874 return -ENOMEM;
2875
2876 rcu_read_lock();
2877 ret = mptcp_init_sched(mptcp_sk(sk),
2878 mptcp_sched_find(mptcp_get_scheduler(net)));
2879 rcu_read_unlock();
2880 if (ret)
2881 return ret;
2882
2883 set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags);
2884
2885 /* fetch the ca name; do it outside __mptcp_init_sock(), so that clone will
2886 * propagate the correct value
2887 */
2888 mptcp_ca_reset(sk);
2889
2890 sk_sockets_allocated_inc(sk);
2891 sk->sk_rcvbuf = READ_ONCE(net->ipv4.sysctl_tcp_rmem[1]);
2892 sk->sk_sndbuf = READ_ONCE(net->ipv4.sysctl_tcp_wmem[1]);
2893
2894 return 0;
2895}
2896
2897static void __mptcp_clear_xmit(struct sock *sk)
2898{
2899 struct mptcp_sock *msk = mptcp_sk(sk);
2900 struct mptcp_data_frag *dtmp, *dfrag;
2901
2902 WRITE_ONCE(msk->first_pending, NULL);
2903 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list)
2904 dfrag_clear(sk, dfrag);
2905}
2906
2907void mptcp_cancel_work(struct sock *sk)
2908{
2909 struct mptcp_sock *msk = mptcp_sk(sk);
2910
2911 if (cancel_work_sync(&msk->work))
2912 __sock_put(sk);
2913}
2914
2915void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how)
2916{
2917 lock_sock(ssk);
2918
2919 switch (ssk->sk_state) {
2920 case TCP_LISTEN:
2921 if (!(how & RCV_SHUTDOWN))
2922 break;
2923 fallthrough;
2924 case TCP_SYN_SENT:
2925 WARN_ON_ONCE(tcp_disconnect(ssk, O_NONBLOCK));
2926 break;
2927 default:
2928 if (__mptcp_check_fallback(mptcp_sk(sk))) {
2929 pr_debug("Fallback\n");
2930 ssk->sk_shutdown |= how;
2931 tcp_shutdown(ssk, how);
2932
2933 /* simulate the data_fin ack reception to let the state
2934 * machine move forward
2935 */
2936 WRITE_ONCE(mptcp_sk(sk)->snd_una, mptcp_sk(sk)->snd_nxt);
2937 mptcp_schedule_work(sk);
2938 } else {
2939 pr_debug("Sending DATA_FIN on subflow %p\n", ssk);
2940 tcp_send_ack(ssk);
2941 if (!mptcp_rtx_timer_pending(sk))
2942 mptcp_reset_rtx_timer(sk);
2943 }
2944 break;
2945 }
2946
2947 release_sock(ssk);
2948}
2949
2950void mptcp_set_state(struct sock *sk, int state)
2951{
2952 int oldstate = sk->sk_state;
2953
2954 switch (state) {
2955 case TCP_ESTABLISHED:
2956 if (oldstate != TCP_ESTABLISHED)
2957 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_CURRESTAB);
2958 break;
2959 case TCP_CLOSE_WAIT:
2960 /* Unlike TCP, MPTCP sk would not have the TCP_SYN_RECV state:
2961 * MPTCP "accepted" sockets will be created later on. So no
2962 * transition from TCP_SYN_RECV to TCP_CLOSE_WAIT.
2963 */
2964 break;
2965 default:
2966 if (oldstate == TCP_ESTABLISHED || oldstate == TCP_CLOSE_WAIT)
2967 MPTCP_DEC_STATS(sock_net(sk), MPTCP_MIB_CURRESTAB);
2968 }
2969
2970 inet_sk_state_store(sk, state);
2971}
2972
2973static const unsigned char new_state[16] = {
2974 /* current state: new state: action: */
2975 [0 /* (Invalid) */] = TCP_CLOSE,
2976 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2977 [TCP_SYN_SENT] = TCP_CLOSE,
2978 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2979 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1,
2980 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2,
2981 [TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */
2982 [TCP_CLOSE] = TCP_CLOSE,
2983 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN,
2984 [TCP_LAST_ACK] = TCP_LAST_ACK,
2985 [TCP_LISTEN] = TCP_CLOSE,
2986 [TCP_CLOSING] = TCP_CLOSING,
2987 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */
2988};
2989
2990static int mptcp_close_state(struct sock *sk)
2991{
2992 int next = (int)new_state[sk->sk_state];
2993 int ns = next & TCP_STATE_MASK;
2994
2995 mptcp_set_state(sk, ns);
2996
2997 return next & TCP_ACTION_FIN;
2998}
2999
3000static void mptcp_check_send_data_fin(struct sock *sk)
3001{
3002 struct mptcp_subflow_context *subflow;
3003 struct mptcp_sock *msk = mptcp_sk(sk);
3004
3005 pr_debug("msk=%p snd_data_fin_enable=%d pending=%d snd_nxt=%llu write_seq=%llu\n",
3006 msk, msk->snd_data_fin_enable, !!mptcp_send_head(sk),
3007 msk->snd_nxt, msk->write_seq);
3008
3009 /* we still need to enqueue subflows or not really shutting down,
3010 * skip this
3011 */
3012 if (!msk->snd_data_fin_enable || msk->snd_nxt + 1 != msk->write_seq ||
3013 mptcp_send_head(sk))
3014 return;
3015
3016 WRITE_ONCE(msk->snd_nxt, msk->write_seq);
3017
3018 mptcp_for_each_subflow(msk, subflow) {
3019 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
3020
3021 mptcp_subflow_shutdown(sk, tcp_sk, SEND_SHUTDOWN);
3022 }
3023}
3024
3025static void __mptcp_wr_shutdown(struct sock *sk)
3026{
3027 struct mptcp_sock *msk = mptcp_sk(sk);
3028
3029 pr_debug("msk=%p snd_data_fin_enable=%d shutdown=%x state=%d pending=%d\n",
3030 msk, msk->snd_data_fin_enable, sk->sk_shutdown, sk->sk_state,
3031 !!mptcp_send_head(sk));
3032
3033 /* will be ignored by fallback sockets */
3034 WRITE_ONCE(msk->write_seq, msk->write_seq + 1);
3035 WRITE_ONCE(msk->snd_data_fin_enable, 1);
3036
3037 mptcp_check_send_data_fin(sk);
3038}
3039
3040static void __mptcp_destroy_sock(struct sock *sk)
3041{
3042 struct mptcp_sock *msk = mptcp_sk(sk);
3043
3044 pr_debug("msk=%p\n", msk);
3045
3046 might_sleep();
3047
3048 mptcp_stop_rtx_timer(sk);
3049 sk_stop_timer(sk, &sk->sk_timer);
3050 msk->pm.status = 0;
3051 mptcp_release_sched(msk);
3052
3053 sk->sk_prot->destroy(sk);
3054
3055 WARN_ON_ONCE(READ_ONCE(msk->rmem_fwd_alloc));
3056 WARN_ON_ONCE(msk->rmem_released);
3057 sk_stream_kill_queues(sk);
3058 xfrm_sk_free_policy(sk);
3059
3060 sock_put(sk);
3061}
3062
3063void __mptcp_unaccepted_force_close(struct sock *sk)
3064{
3065 sock_set_flag(sk, SOCK_DEAD);
3066 mptcp_do_fastclose(sk);
3067 __mptcp_destroy_sock(sk);
3068}
3069
3070static __poll_t mptcp_check_readable(struct sock *sk)
3071{
3072 return mptcp_epollin_ready(sk) ? EPOLLIN | EPOLLRDNORM : 0;
3073}
3074
3075static void mptcp_check_listen_stop(struct sock *sk)
3076{
3077 struct sock *ssk;
3078
3079 if (inet_sk_state_load(sk) != TCP_LISTEN)
3080 return;
3081
3082 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
3083 ssk = mptcp_sk(sk)->first;
3084 if (WARN_ON_ONCE(!ssk || inet_sk_state_load(ssk) != TCP_LISTEN))
3085 return;
3086
3087 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
3088 tcp_set_state(ssk, TCP_CLOSE);
3089 mptcp_subflow_queue_clean(sk, ssk);
3090 inet_csk_listen_stop(ssk);
3091 mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CLOSED);
3092 release_sock(ssk);
3093}
3094
3095bool __mptcp_close(struct sock *sk, long timeout)
3096{
3097 struct mptcp_subflow_context *subflow;
3098 struct mptcp_sock *msk = mptcp_sk(sk);
3099 bool do_cancel_work = false;
3100 int subflows_alive = 0;
3101
3102 WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
3103
3104 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) {
3105 mptcp_check_listen_stop(sk);
3106 mptcp_set_state(sk, TCP_CLOSE);
3107 goto cleanup;
3108 }
3109
3110 if (mptcp_data_avail(msk) || timeout < 0) {
3111 /* If the msk has read data, or the caller explicitly ask it,
3112 * do the MPTCP equivalent of TCP reset, aka MPTCP fastclose
3113 */
3114 mptcp_do_fastclose(sk);
3115 timeout = 0;
3116 } else if (mptcp_close_state(sk)) {
3117 __mptcp_wr_shutdown(sk);
3118 }
3119
3120 sk_stream_wait_close(sk, timeout);
3121
3122cleanup:
3123 /* orphan all the subflows */
3124 mptcp_for_each_subflow(msk, subflow) {
3125 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3126 bool slow = lock_sock_fast_nested(ssk);
3127
3128 subflows_alive += ssk->sk_state != TCP_CLOSE;
3129
3130 /* since the close timeout takes precedence on the fail one,
3131 * cancel the latter
3132 */
3133 if (ssk == msk->first)
3134 subflow->fail_tout = 0;
3135
3136 /* detach from the parent socket, but allow data_ready to
3137 * push incoming data into the mptcp stack, to properly ack it
3138 */
3139 ssk->sk_socket = NULL;
3140 ssk->sk_wq = NULL;
3141 unlock_sock_fast(ssk, slow);
3142 }
3143 sock_orphan(sk);
3144
3145 /* all the subflows are closed, only timeout can change the msk
3146 * state, let's not keep resources busy for no reasons
3147 */
3148 if (subflows_alive == 0)
3149 mptcp_set_state(sk, TCP_CLOSE);
3150
3151 sock_hold(sk);
3152 pr_debug("msk=%p state=%d\n", sk, sk->sk_state);
3153 mptcp_pm_connection_closed(msk);
3154
3155 if (sk->sk_state == TCP_CLOSE) {
3156 __mptcp_destroy_sock(sk);
3157 do_cancel_work = true;
3158 } else {
3159 mptcp_start_tout_timer(sk);
3160 }
3161
3162 return do_cancel_work;
3163}
3164
3165static void mptcp_close(struct sock *sk, long timeout)
3166{
3167 bool do_cancel_work;
3168
3169 lock_sock(sk);
3170
3171 do_cancel_work = __mptcp_close(sk, timeout);
3172 release_sock(sk);
3173 if (do_cancel_work)
3174 mptcp_cancel_work(sk);
3175
3176 sock_put(sk);
3177}
3178
3179static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk)
3180{
3181#if IS_ENABLED(CONFIG_MPTCP_IPV6)
3182 const struct ipv6_pinfo *ssk6 = inet6_sk(ssk);
3183 struct ipv6_pinfo *msk6 = inet6_sk(msk);
3184
3185 msk->sk_v6_daddr = ssk->sk_v6_daddr;
3186 msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr;
3187
3188 if (msk6 && ssk6) {
3189 msk6->saddr = ssk6->saddr;
3190 msk6->flow_label = ssk6->flow_label;
3191 }
3192#endif
3193
3194 inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num;
3195 inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport;
3196 inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport;
3197 inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr;
3198 inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr;
3199 inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr;
3200}
3201
3202static int mptcp_disconnect(struct sock *sk, int flags)
3203{
3204 struct mptcp_sock *msk = mptcp_sk(sk);
3205
3206 /* We are on the fastopen error path. We can't call straight into the
3207 * subflows cleanup code due to lock nesting (we are already under
3208 * msk->firstsocket lock).
3209 */
3210 if (msk->fastopening)
3211 return -EBUSY;
3212
3213 mptcp_check_listen_stop(sk);
3214 mptcp_set_state(sk, TCP_CLOSE);
3215
3216 mptcp_stop_rtx_timer(sk);
3217 mptcp_stop_tout_timer(sk);
3218
3219 mptcp_pm_connection_closed(msk);
3220
3221 /* msk->subflow is still intact, the following will not free the first
3222 * subflow
3223 */
3224 mptcp_destroy_common(msk, MPTCP_CF_FASTCLOSE);
3225 WRITE_ONCE(msk->flags, 0);
3226 msk->cb_flags = 0;
3227 msk->recovery = false;
3228 WRITE_ONCE(msk->can_ack, false);
3229 WRITE_ONCE(msk->fully_established, false);
3230 WRITE_ONCE(msk->rcv_data_fin, false);
3231 WRITE_ONCE(msk->snd_data_fin_enable, false);
3232 WRITE_ONCE(msk->rcv_fastclose, false);
3233 WRITE_ONCE(msk->use_64bit_ack, false);
3234 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
3235 mptcp_pm_data_reset(msk);
3236 mptcp_ca_reset(sk);
3237 msk->bytes_consumed = 0;
3238 msk->bytes_acked = 0;
3239 msk->bytes_received = 0;
3240 msk->bytes_sent = 0;
3241 msk->bytes_retrans = 0;
3242 msk->rcvspace_init = 0;
3243
3244 WRITE_ONCE(sk->sk_shutdown, 0);
3245 sk_error_report(sk);
3246 return 0;
3247}
3248
3249#if IS_ENABLED(CONFIG_MPTCP_IPV6)
3250static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk)
3251{
3252 unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo);
3253
3254 return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
3255}
3256
3257static void mptcp_copy_ip6_options(struct sock *newsk, const struct sock *sk)
3258{
3259 const struct ipv6_pinfo *np = inet6_sk(sk);
3260 struct ipv6_txoptions *opt;
3261 struct ipv6_pinfo *newnp;
3262
3263 newnp = inet6_sk(newsk);
3264
3265 rcu_read_lock();
3266 opt = rcu_dereference(np->opt);
3267 if (opt) {
3268 opt = ipv6_dup_options(newsk, opt);
3269 if (!opt)
3270 net_warn_ratelimited("%s: Failed to copy ip6 options\n", __func__);
3271 }
3272 RCU_INIT_POINTER(newnp->opt, opt);
3273 rcu_read_unlock();
3274}
3275#endif
3276
3277static void mptcp_copy_ip_options(struct sock *newsk, const struct sock *sk)
3278{
3279 struct ip_options_rcu *inet_opt, *newopt = NULL;
3280 const struct inet_sock *inet = inet_sk(sk);
3281 struct inet_sock *newinet;
3282
3283 newinet = inet_sk(newsk);
3284
3285 rcu_read_lock();
3286 inet_opt = rcu_dereference(inet->inet_opt);
3287 if (inet_opt) {
3288 newopt = sock_kmalloc(newsk, sizeof(*inet_opt) +
3289 inet_opt->opt.optlen, GFP_ATOMIC);
3290 if (newopt)
3291 memcpy(newopt, inet_opt, sizeof(*inet_opt) +
3292 inet_opt->opt.optlen);
3293 else
3294 net_warn_ratelimited("%s: Failed to copy ip options\n", __func__);
3295 }
3296 RCU_INIT_POINTER(newinet->inet_opt, newopt);
3297 rcu_read_unlock();
3298}
3299
3300struct sock *mptcp_sk_clone_init(const struct sock *sk,
3301 const struct mptcp_options_received *mp_opt,
3302 struct sock *ssk,
3303 struct request_sock *req)
3304{
3305 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
3306 struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC);
3307 struct mptcp_subflow_context *subflow;
3308 struct mptcp_sock *msk;
3309
3310 if (!nsk)
3311 return NULL;
3312
3313#if IS_ENABLED(CONFIG_MPTCP_IPV6)
3314 if (nsk->sk_family == AF_INET6)
3315 inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk);
3316#endif
3317
3318 __mptcp_init_sock(nsk);
3319
3320#if IS_ENABLED(CONFIG_MPTCP_IPV6)
3321 if (nsk->sk_family == AF_INET6)
3322 mptcp_copy_ip6_options(nsk, sk);
3323 else
3324#endif
3325 mptcp_copy_ip_options(nsk, sk);
3326
3327 msk = mptcp_sk(nsk);
3328 WRITE_ONCE(msk->local_key, subflow_req->local_key);
3329 WRITE_ONCE(msk->token, subflow_req->token);
3330 msk->in_accept_queue = 1;
3331 WRITE_ONCE(msk->fully_established, false);
3332 if (mp_opt->suboptions & OPTION_MPTCP_CSUMREQD)
3333 WRITE_ONCE(msk->csum_enabled, true);
3334
3335 WRITE_ONCE(msk->write_seq, subflow_req->idsn + 1);
3336 WRITE_ONCE(msk->snd_nxt, msk->write_seq);
3337 WRITE_ONCE(msk->snd_una, msk->write_seq);
3338 WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd);
3339 msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq;
3340 mptcp_init_sched(msk, mptcp_sk(sk)->sched);
3341
3342 /* passive msk is created after the first/MPC subflow */
3343 msk->subflow_id = 2;
3344
3345 sock_reset_flag(nsk, SOCK_RCU_FREE);
3346 security_inet_csk_clone(nsk, req);
3347
3348 /* this can't race with mptcp_close(), as the msk is
3349 * not yet exposted to user-space
3350 */
3351 mptcp_set_state(nsk, TCP_ESTABLISHED);
3352
3353 /* The msk maintain a ref to each subflow in the connections list */
3354 WRITE_ONCE(msk->first, ssk);
3355 subflow = mptcp_subflow_ctx(ssk);
3356 list_add(&subflow->node, &msk->conn_list);
3357 sock_hold(ssk);
3358
3359 /* new mpc subflow takes ownership of the newly
3360 * created mptcp socket
3361 */
3362 mptcp_token_accept(subflow_req, msk);
3363
3364 /* set msk addresses early to ensure mptcp_pm_get_local_id()
3365 * uses the correct data
3366 */
3367 mptcp_copy_inaddrs(nsk, ssk);
3368 __mptcp_propagate_sndbuf(nsk, ssk);
3369
3370 mptcp_rcv_space_init(msk, ssk);
3371
3372 if (mp_opt->suboptions & OPTION_MPTCP_MPC_ACK)
3373 __mptcp_subflow_fully_established(msk, subflow, mp_opt);
3374 bh_unlock_sock(nsk);
3375
3376 /* note: the newly allocated socket refcount is 2 now */
3377 return nsk;
3378}
3379
3380void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk)
3381{
3382 const struct tcp_sock *tp = tcp_sk(ssk);
3383
3384 msk->rcvspace_init = 1;
3385 msk->rcvq_space.copied = 0;
3386 msk->rcvq_space.rtt_us = 0;
3387
3388 msk->rcvq_space.time = tp->tcp_mstamp;
3389
3390 /* initial rcv_space offering made to peer */
3391 msk->rcvq_space.space = min_t(u32, tp->rcv_wnd,
3392 TCP_INIT_CWND * tp->advmss);
3393 if (msk->rcvq_space.space == 0)
3394 msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT;
3395}
3396
3397void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags)
3398{
3399 struct mptcp_subflow_context *subflow, *tmp;
3400 struct sock *sk = (struct sock *)msk;
3401
3402 __mptcp_clear_xmit(sk);
3403
3404 /* join list will be eventually flushed (with rst) at sock lock release time */
3405 mptcp_for_each_subflow_safe(msk, subflow, tmp)
3406 __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), subflow, flags);
3407
3408 /* move to sk_receive_queue, sk_stream_kill_queues will purge it */
3409 mptcp_data_lock(sk);
3410 skb_queue_splice_tail_init(&msk->receive_queue, &sk->sk_receive_queue);
3411 __skb_queue_purge(&sk->sk_receive_queue);
3412 skb_rbtree_purge(&msk->out_of_order_queue);
3413 mptcp_data_unlock(sk);
3414
3415 /* move all the rx fwd alloc into the sk_mem_reclaim_final in
3416 * inet_sock_destruct() will dispose it
3417 */
3418 sk_forward_alloc_add(sk, msk->rmem_fwd_alloc);
3419 WRITE_ONCE(msk->rmem_fwd_alloc, 0);
3420 mptcp_token_destroy(msk);
3421 mptcp_pm_free_anno_list(msk);
3422 mptcp_free_local_addr_list(msk);
3423}
3424
3425static void mptcp_destroy(struct sock *sk)
3426{
3427 struct mptcp_sock *msk = mptcp_sk(sk);
3428
3429 /* allow the following to close even the initial subflow */
3430 msk->free_first = 1;
3431 mptcp_destroy_common(msk, 0);
3432 sk_sockets_allocated_dec(sk);
3433}
3434
3435void __mptcp_data_acked(struct sock *sk)
3436{
3437 if (!sock_owned_by_user(sk))
3438 __mptcp_clean_una(sk);
3439 else
3440 __set_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->cb_flags);
3441}
3442
3443void __mptcp_check_push(struct sock *sk, struct sock *ssk)
3444{
3445 if (!mptcp_send_head(sk))
3446 return;
3447
3448 if (!sock_owned_by_user(sk))
3449 __mptcp_subflow_push_pending(sk, ssk, false);
3450 else
3451 __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags);
3452}
3453
3454#define MPTCP_FLAGS_PROCESS_CTX_NEED (BIT(MPTCP_PUSH_PENDING) | \
3455 BIT(MPTCP_RETRANSMIT) | \
3456 BIT(MPTCP_FLUSH_JOIN_LIST))
3457
3458/* processes deferred events and flush wmem */
3459static void mptcp_release_cb(struct sock *sk)
3460 __must_hold(&sk->sk_lock.slock)
3461{
3462 struct mptcp_sock *msk = mptcp_sk(sk);
3463
3464 for (;;) {
3465 unsigned long flags = (msk->cb_flags & MPTCP_FLAGS_PROCESS_CTX_NEED);
3466 struct list_head join_list;
3467
3468 if (!flags)
3469 break;
3470
3471 INIT_LIST_HEAD(&join_list);
3472 list_splice_init(&msk->join_list, &join_list);
3473
3474 /* the following actions acquire the subflow socket lock
3475 *
3476 * 1) can't be invoked in atomic scope
3477 * 2) must avoid ABBA deadlock with msk socket spinlock: the RX
3478 * datapath acquires the msk socket spinlock while helding
3479 * the subflow socket lock
3480 */
3481 msk->cb_flags &= ~flags;
3482 spin_unlock_bh(&sk->sk_lock.slock);
3483
3484 if (flags & BIT(MPTCP_FLUSH_JOIN_LIST))
3485 __mptcp_flush_join_list(sk, &join_list);
3486 if (flags & BIT(MPTCP_PUSH_PENDING))
3487 __mptcp_push_pending(sk, 0);
3488 if (flags & BIT(MPTCP_RETRANSMIT))
3489 __mptcp_retrans(sk);
3490
3491 cond_resched();
3492 spin_lock_bh(&sk->sk_lock.slock);
3493 }
3494
3495 if (__test_and_clear_bit(MPTCP_CLEAN_UNA, &msk->cb_flags))
3496 __mptcp_clean_una_wakeup(sk);
3497 if (unlikely(msk->cb_flags)) {
3498 /* be sure to sync the msk state before taking actions
3499 * depending on sk_state (MPTCP_ERROR_REPORT)
3500 * On sk release avoid actions depending on the first subflow
3501 */
3502 if (__test_and_clear_bit(MPTCP_SYNC_STATE, &msk->cb_flags) && msk->first)
3503 __mptcp_sync_state(sk, msk->pending_state);
3504 if (__test_and_clear_bit(MPTCP_ERROR_REPORT, &msk->cb_flags))
3505 __mptcp_error_report(sk);
3506 if (__test_and_clear_bit(MPTCP_SYNC_SNDBUF, &msk->cb_flags))
3507 __mptcp_sync_sndbuf(sk);
3508 }
3509
3510 __mptcp_update_rmem(sk);
3511}
3512
3513/* MP_JOIN client subflow must wait for 4th ack before sending any data:
3514 * TCP can't schedule delack timer before the subflow is fully established.
3515 * MPTCP uses the delack timer to do 3rd ack retransmissions
3516 */
3517static void schedule_3rdack_retransmission(struct sock *ssk)
3518{
3519 struct inet_connection_sock *icsk = inet_csk(ssk);
3520 struct tcp_sock *tp = tcp_sk(ssk);
3521 unsigned long timeout;
3522
3523 if (READ_ONCE(mptcp_subflow_ctx(ssk)->fully_established))
3524 return;
3525
3526 /* reschedule with a timeout above RTT, as we must look only for drop */
3527 if (tp->srtt_us)
3528 timeout = usecs_to_jiffies(tp->srtt_us >> (3 - 1));
3529 else
3530 timeout = TCP_TIMEOUT_INIT;
3531 timeout += jiffies;
3532
3533 WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER);
3534 smp_store_release(&icsk->icsk_ack.pending,
3535 icsk->icsk_ack.pending | ICSK_ACK_SCHED | ICSK_ACK_TIMER);
3536 icsk->icsk_ack.timeout = timeout;
3537 sk_reset_timer(ssk, &icsk->icsk_delack_timer, timeout);
3538}
3539
3540void mptcp_subflow_process_delegated(struct sock *ssk, long status)
3541{
3542 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
3543 struct sock *sk = subflow->conn;
3544
3545 if (status & BIT(MPTCP_DELEGATE_SEND)) {
3546 mptcp_data_lock(sk);
3547 if (!sock_owned_by_user(sk))
3548 __mptcp_subflow_push_pending(sk, ssk, true);
3549 else
3550 __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags);
3551 mptcp_data_unlock(sk);
3552 }
3553 if (status & BIT(MPTCP_DELEGATE_SNDBUF)) {
3554 mptcp_data_lock(sk);
3555 if (!sock_owned_by_user(sk))
3556 __mptcp_sync_sndbuf(sk);
3557 else
3558 __set_bit(MPTCP_SYNC_SNDBUF, &mptcp_sk(sk)->cb_flags);
3559 mptcp_data_unlock(sk);
3560 }
3561 if (status & BIT(MPTCP_DELEGATE_ACK))
3562 schedule_3rdack_retransmission(ssk);
3563}
3564
3565static int mptcp_hash(struct sock *sk)
3566{
3567 /* should never be called,
3568 * we hash the TCP subflows not the MPTCP socket
3569 */
3570 WARN_ON_ONCE(1);
3571 return 0;
3572}
3573
3574static void mptcp_unhash(struct sock *sk)
3575{
3576 /* called from sk_common_release(), but nothing to do here */
3577}
3578
3579static int mptcp_get_port(struct sock *sk, unsigned short snum)
3580{
3581 struct mptcp_sock *msk = mptcp_sk(sk);
3582
3583 pr_debug("msk=%p, ssk=%p\n", msk, msk->first);
3584 if (WARN_ON_ONCE(!msk->first))
3585 return -EINVAL;
3586
3587 return inet_csk_get_port(msk->first, snum);
3588}
3589
3590void mptcp_finish_connect(struct sock *ssk)
3591{
3592 struct mptcp_subflow_context *subflow;
3593 struct mptcp_sock *msk;
3594 struct sock *sk;
3595
3596 subflow = mptcp_subflow_ctx(ssk);
3597 sk = subflow->conn;
3598 msk = mptcp_sk(sk);
3599
3600 pr_debug("msk=%p, token=%u\n", sk, subflow->token);
3601
3602 subflow->map_seq = subflow->iasn;
3603 subflow->map_subflow_seq = 1;
3604
3605 /* the socket is not connected yet, no msk/subflow ops can access/race
3606 * accessing the field below
3607 */
3608 WRITE_ONCE(msk->local_key, subflow->local_key);
3609
3610 mptcp_pm_new_connection(msk, ssk, 0);
3611}
3612
3613void mptcp_sock_graft(struct sock *sk, struct socket *parent)
3614{
3615 write_lock_bh(&sk->sk_callback_lock);
3616 rcu_assign_pointer(sk->sk_wq, &parent->wq);
3617 sk_set_socket(sk, parent);
3618 sk->sk_uid = SOCK_INODE(parent)->i_uid;
3619 write_unlock_bh(&sk->sk_callback_lock);
3620}
3621
3622bool mptcp_finish_join(struct sock *ssk)
3623{
3624 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
3625 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
3626 struct sock *parent = (void *)msk;
3627 bool ret = true;
3628
3629 pr_debug("msk=%p, subflow=%p\n", msk, subflow);
3630
3631 /* mptcp socket already closing? */
3632 if (!mptcp_is_fully_established(parent)) {
3633 subflow->reset_reason = MPTCP_RST_EMPTCP;
3634 return false;
3635 }
3636
3637 /* active subflow, already present inside the conn_list */
3638 if (!list_empty(&subflow->node)) {
3639 mptcp_subflow_joined(msk, ssk);
3640 mptcp_propagate_sndbuf(parent, ssk);
3641 return true;
3642 }
3643
3644 if (!mptcp_pm_allow_new_subflow(msk))
3645 goto err_prohibited;
3646
3647 /* If we can't acquire msk socket lock here, let the release callback
3648 * handle it
3649 */
3650 mptcp_data_lock(parent);
3651 if (!sock_owned_by_user(parent)) {
3652 ret = __mptcp_finish_join(msk, ssk);
3653 if (ret) {
3654 sock_hold(ssk);
3655 list_add_tail(&subflow->node, &msk->conn_list);
3656 }
3657 } else {
3658 sock_hold(ssk);
3659 list_add_tail(&subflow->node, &msk->join_list);
3660 __set_bit(MPTCP_FLUSH_JOIN_LIST, &msk->cb_flags);
3661 }
3662 mptcp_data_unlock(parent);
3663
3664 if (!ret) {
3665err_prohibited:
3666 subflow->reset_reason = MPTCP_RST_EPROHIBIT;
3667 return false;
3668 }
3669
3670 return true;
3671}
3672
3673static void mptcp_shutdown(struct sock *sk, int how)
3674{
3675 pr_debug("sk=%p, how=%d\n", sk, how);
3676
3677 if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk))
3678 __mptcp_wr_shutdown(sk);
3679}
3680
3681static int mptcp_forward_alloc_get(const struct sock *sk)
3682{
3683 return READ_ONCE(sk->sk_forward_alloc) +
3684 READ_ONCE(mptcp_sk(sk)->rmem_fwd_alloc);
3685}
3686
3687static int mptcp_ioctl_outq(const struct mptcp_sock *msk, u64 v)
3688{
3689 const struct sock *sk = (void *)msk;
3690 u64 delta;
3691
3692 if (sk->sk_state == TCP_LISTEN)
3693 return -EINVAL;
3694
3695 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
3696 return 0;
3697
3698 delta = msk->write_seq - v;
3699 if (__mptcp_check_fallback(msk) && msk->first) {
3700 struct tcp_sock *tp = tcp_sk(msk->first);
3701
3702 /* the first subflow is disconnected after close - see
3703 * __mptcp_close_ssk(). tcp_disconnect() moves the write_seq
3704 * so ignore that status, too.
3705 */
3706 if (!((1 << msk->first->sk_state) &
3707 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE)))
3708 delta += READ_ONCE(tp->write_seq) - tp->snd_una;
3709 }
3710 if (delta > INT_MAX)
3711 delta = INT_MAX;
3712
3713 return (int)delta;
3714}
3715
3716static int mptcp_ioctl(struct sock *sk, int cmd, int *karg)
3717{
3718 struct mptcp_sock *msk = mptcp_sk(sk);
3719 bool slow;
3720
3721 switch (cmd) {
3722 case SIOCINQ:
3723 if (sk->sk_state == TCP_LISTEN)
3724 return -EINVAL;
3725
3726 lock_sock(sk);
3727 __mptcp_move_skbs(msk);
3728 *karg = mptcp_inq_hint(sk);
3729 release_sock(sk);
3730 break;
3731 case SIOCOUTQ:
3732 slow = lock_sock_fast(sk);
3733 *karg = mptcp_ioctl_outq(msk, READ_ONCE(msk->snd_una));
3734 unlock_sock_fast(sk, slow);
3735 break;
3736 case SIOCOUTQNSD:
3737 slow = lock_sock_fast(sk);
3738 *karg = mptcp_ioctl_outq(msk, msk->snd_nxt);
3739 unlock_sock_fast(sk, slow);
3740 break;
3741 default:
3742 return -ENOIOCTLCMD;
3743 }
3744
3745 return 0;
3746}
3747
3748static int mptcp_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
3749{
3750 struct mptcp_subflow_context *subflow;
3751 struct mptcp_sock *msk = mptcp_sk(sk);
3752 int err = -EINVAL;
3753 struct sock *ssk;
3754
3755 ssk = __mptcp_nmpc_sk(msk);
3756 if (IS_ERR(ssk))
3757 return PTR_ERR(ssk);
3758
3759 mptcp_set_state(sk, TCP_SYN_SENT);
3760 subflow = mptcp_subflow_ctx(ssk);
3761#ifdef CONFIG_TCP_MD5SIG
3762 /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
3763 * TCP option space.
3764 */
3765 if (rcu_access_pointer(tcp_sk(ssk)->md5sig_info))
3766 mptcp_subflow_early_fallback(msk, subflow);
3767#endif
3768 if (subflow->request_mptcp) {
3769 if (mptcp_active_should_disable(sk)) {
3770 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_MPCAPABLEACTIVEDISABLED);
3771 mptcp_subflow_early_fallback(msk, subflow);
3772 } else if (mptcp_token_new_connect(ssk) < 0) {
3773 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_TOKENFALLBACKINIT);
3774 mptcp_subflow_early_fallback(msk, subflow);
3775 }
3776 }
3777
3778 WRITE_ONCE(msk->write_seq, subflow->idsn);
3779 WRITE_ONCE(msk->snd_nxt, subflow->idsn);
3780 WRITE_ONCE(msk->snd_una, subflow->idsn);
3781 if (likely(!__mptcp_check_fallback(msk)))
3782 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVE);
3783
3784 /* if reaching here via the fastopen/sendmsg path, the caller already
3785 * acquired the subflow socket lock, too.
3786 */
3787 if (!msk->fastopening)
3788 lock_sock(ssk);
3789
3790 /* the following mirrors closely a very small chunk of code from
3791 * __inet_stream_connect()
3792 */
3793 if (ssk->sk_state != TCP_CLOSE)
3794 goto out;
3795
3796 if (BPF_CGROUP_PRE_CONNECT_ENABLED(ssk)) {
3797 err = ssk->sk_prot->pre_connect(ssk, uaddr, addr_len);
3798 if (err)
3799 goto out;
3800 }
3801
3802 err = ssk->sk_prot->connect(ssk, uaddr, addr_len);
3803 if (err < 0)
3804 goto out;
3805
3806 inet_assign_bit(DEFER_CONNECT, sk, inet_test_bit(DEFER_CONNECT, ssk));
3807
3808out:
3809 if (!msk->fastopening)
3810 release_sock(ssk);
3811
3812 /* on successful connect, the msk state will be moved to established by
3813 * subflow_finish_connect()
3814 */
3815 if (unlikely(err)) {
3816 /* avoid leaving a dangling token in an unconnected socket */
3817 mptcp_token_destroy(msk);
3818 mptcp_set_state(sk, TCP_CLOSE);
3819 return err;
3820 }
3821
3822 mptcp_copy_inaddrs(sk, ssk);
3823 return 0;
3824}
3825
3826static struct proto mptcp_prot = {
3827 .name = "MPTCP",
3828 .owner = THIS_MODULE,
3829 .init = mptcp_init_sock,
3830 .connect = mptcp_connect,
3831 .disconnect = mptcp_disconnect,
3832 .close = mptcp_close,
3833 .setsockopt = mptcp_setsockopt,
3834 .getsockopt = mptcp_getsockopt,
3835 .shutdown = mptcp_shutdown,
3836 .destroy = mptcp_destroy,
3837 .sendmsg = mptcp_sendmsg,
3838 .ioctl = mptcp_ioctl,
3839 .recvmsg = mptcp_recvmsg,
3840 .release_cb = mptcp_release_cb,
3841 .hash = mptcp_hash,
3842 .unhash = mptcp_unhash,
3843 .get_port = mptcp_get_port,
3844 .forward_alloc_get = mptcp_forward_alloc_get,
3845 .stream_memory_free = mptcp_stream_memory_free,
3846 .sockets_allocated = &mptcp_sockets_allocated,
3847
3848 .memory_allocated = &tcp_memory_allocated,
3849 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc,
3850
3851 .memory_pressure = &tcp_memory_pressure,
3852 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
3853 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
3854 .sysctl_mem = sysctl_tcp_mem,
3855 .obj_size = sizeof(struct mptcp_sock),
3856 .slab_flags = SLAB_TYPESAFE_BY_RCU,
3857 .no_autobind = true,
3858};
3859
3860static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
3861{
3862 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3863 struct sock *ssk, *sk = sock->sk;
3864 int err = -EINVAL;
3865
3866 lock_sock(sk);
3867 ssk = __mptcp_nmpc_sk(msk);
3868 if (IS_ERR(ssk)) {
3869 err = PTR_ERR(ssk);
3870 goto unlock;
3871 }
3872
3873 if (sk->sk_family == AF_INET)
3874 err = inet_bind_sk(ssk, uaddr, addr_len);
3875#if IS_ENABLED(CONFIG_MPTCP_IPV6)
3876 else if (sk->sk_family == AF_INET6)
3877 err = inet6_bind_sk(ssk, uaddr, addr_len);
3878#endif
3879 if (!err)
3880 mptcp_copy_inaddrs(sk, ssk);
3881
3882unlock:
3883 release_sock(sk);
3884 return err;
3885}
3886
3887static int mptcp_listen(struct socket *sock, int backlog)
3888{
3889 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3890 struct sock *sk = sock->sk;
3891 struct sock *ssk;
3892 int err;
3893
3894 pr_debug("msk=%p\n", msk);
3895
3896 lock_sock(sk);
3897
3898 err = -EINVAL;
3899 if (sock->state != SS_UNCONNECTED || sock->type != SOCK_STREAM)
3900 goto unlock;
3901
3902 ssk = __mptcp_nmpc_sk(msk);
3903 if (IS_ERR(ssk)) {
3904 err = PTR_ERR(ssk);
3905 goto unlock;
3906 }
3907
3908 mptcp_set_state(sk, TCP_LISTEN);
3909 sock_set_flag(sk, SOCK_RCU_FREE);
3910
3911 lock_sock(ssk);
3912 err = __inet_listen_sk(ssk, backlog);
3913 release_sock(ssk);
3914 mptcp_set_state(sk, inet_sk_state_load(ssk));
3915
3916 if (!err) {
3917 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
3918 mptcp_copy_inaddrs(sk, ssk);
3919 mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CREATED);
3920 }
3921
3922unlock:
3923 release_sock(sk);
3924 return err;
3925}
3926
3927static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
3928 struct proto_accept_arg *arg)
3929{
3930 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3931 struct sock *ssk, *newsk;
3932
3933 pr_debug("msk=%p\n", msk);
3934
3935 /* Buggy applications can call accept on socket states other then LISTEN
3936 * but no need to allocate the first subflow just to error out.
3937 */
3938 ssk = READ_ONCE(msk->first);
3939 if (!ssk)
3940 return -EINVAL;
3941
3942 pr_debug("ssk=%p, listener=%p\n", ssk, mptcp_subflow_ctx(ssk));
3943 newsk = inet_csk_accept(ssk, arg);
3944 if (!newsk)
3945 return arg->err;
3946
3947 pr_debug("newsk=%p, subflow is mptcp=%d\n", newsk, sk_is_mptcp(newsk));
3948 if (sk_is_mptcp(newsk)) {
3949 struct mptcp_subflow_context *subflow;
3950 struct sock *new_mptcp_sock;
3951
3952 subflow = mptcp_subflow_ctx(newsk);
3953 new_mptcp_sock = subflow->conn;
3954
3955 /* is_mptcp should be false if subflow->conn is missing, see
3956 * subflow_syn_recv_sock()
3957 */
3958 if (WARN_ON_ONCE(!new_mptcp_sock)) {
3959 tcp_sk(newsk)->is_mptcp = 0;
3960 goto tcpfallback;
3961 }
3962
3963 newsk = new_mptcp_sock;
3964 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_MPCAPABLEPASSIVEACK);
3965
3966 newsk->sk_kern_sock = arg->kern;
3967 lock_sock(newsk);
3968 __inet_accept(sock, newsock, newsk);
3969
3970 set_bit(SOCK_CUSTOM_SOCKOPT, &newsock->flags);
3971 msk = mptcp_sk(newsk);
3972 msk->in_accept_queue = 0;
3973
3974 /* set ssk->sk_socket of accept()ed flows to mptcp socket.
3975 * This is needed so NOSPACE flag can be set from tcp stack.
3976 */
3977 mptcp_for_each_subflow(msk, subflow) {
3978 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3979
3980 if (!ssk->sk_socket)
3981 mptcp_sock_graft(ssk, newsock);
3982 }
3983
3984 /* Do late cleanup for the first subflow as necessary. Also
3985 * deal with bad peers not doing a complete shutdown.
3986 */
3987 if (unlikely(inet_sk_state_load(msk->first) == TCP_CLOSE)) {
3988 __mptcp_close_ssk(newsk, msk->first,
3989 mptcp_subflow_ctx(msk->first), 0);
3990 if (unlikely(list_is_singular(&msk->conn_list)))
3991 mptcp_set_state(newsk, TCP_CLOSE);
3992 }
3993 } else {
3994tcpfallback:
3995 newsk->sk_kern_sock = arg->kern;
3996 lock_sock(newsk);
3997 __inet_accept(sock, newsock, newsk);
3998 /* we are being invoked after accepting a non-mp-capable
3999 * flow: sk is a tcp_sk, not an mptcp one.
4000 *
4001 * Hand the socket over to tcp so all further socket ops
4002 * bypass mptcp.
4003 */
4004 WRITE_ONCE(newsock->sk->sk_socket->ops,
4005 mptcp_fallback_tcp_ops(newsock->sk));
4006 }
4007 release_sock(newsk);
4008
4009 return 0;
4010}
4011
4012static __poll_t mptcp_check_writeable(struct mptcp_sock *msk)
4013{
4014 struct sock *sk = (struct sock *)msk;
4015
4016 if (__mptcp_stream_is_writeable(sk, 1))
4017 return EPOLLOUT | EPOLLWRNORM;
4018
4019 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
4020 smp_mb__after_atomic(); /* NOSPACE is changed by mptcp_write_space() */
4021 if (__mptcp_stream_is_writeable(sk, 1))
4022 return EPOLLOUT | EPOLLWRNORM;
4023
4024 return 0;
4025}
4026
4027static __poll_t mptcp_poll(struct file *file, struct socket *sock,
4028 struct poll_table_struct *wait)
4029{
4030 struct sock *sk = sock->sk;
4031 struct mptcp_sock *msk;
4032 __poll_t mask = 0;
4033 u8 shutdown;
4034 int state;
4035
4036 msk = mptcp_sk(sk);
4037 sock_poll_wait(file, sock, wait);
4038
4039 state = inet_sk_state_load(sk);
4040 pr_debug("msk=%p state=%d flags=%lx\n", msk, state, msk->flags);
4041 if (state == TCP_LISTEN) {
4042 struct sock *ssk = READ_ONCE(msk->first);
4043
4044 if (WARN_ON_ONCE(!ssk))
4045 return 0;
4046
4047 return inet_csk_listen_poll(ssk);
4048 }
4049
4050 shutdown = READ_ONCE(sk->sk_shutdown);
4051 if (shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
4052 mask |= EPOLLHUP;
4053 if (shutdown & RCV_SHUTDOWN)
4054 mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
4055
4056 if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) {
4057 mask |= mptcp_check_readable(sk);
4058 if (shutdown & SEND_SHUTDOWN)
4059 mask |= EPOLLOUT | EPOLLWRNORM;
4060 else
4061 mask |= mptcp_check_writeable(msk);
4062 } else if (state == TCP_SYN_SENT &&
4063 inet_test_bit(DEFER_CONNECT, sk)) {
4064 /* cf tcp_poll() note about TFO */
4065 mask |= EPOLLOUT | EPOLLWRNORM;
4066 }
4067
4068 /* This barrier is coupled with smp_wmb() in __mptcp_error_report() */
4069 smp_rmb();
4070 if (READ_ONCE(sk->sk_err))
4071 mask |= EPOLLERR;
4072
4073 return mask;
4074}
4075
4076static const struct proto_ops mptcp_stream_ops = {
4077 .family = PF_INET,
4078 .owner = THIS_MODULE,
4079 .release = inet_release,
4080 .bind = mptcp_bind,
4081 .connect = inet_stream_connect,
4082 .socketpair = sock_no_socketpair,
4083 .accept = mptcp_stream_accept,
4084 .getname = inet_getname,
4085 .poll = mptcp_poll,
4086 .ioctl = inet_ioctl,
4087 .gettstamp = sock_gettstamp,
4088 .listen = mptcp_listen,
4089 .shutdown = inet_shutdown,
4090 .setsockopt = sock_common_setsockopt,
4091 .getsockopt = sock_common_getsockopt,
4092 .sendmsg = inet_sendmsg,
4093 .recvmsg = inet_recvmsg,
4094 .mmap = sock_no_mmap,
4095 .set_rcvlowat = mptcp_set_rcvlowat,
4096};
4097
4098static struct inet_protosw mptcp_protosw = {
4099 .type = SOCK_STREAM,
4100 .protocol = IPPROTO_MPTCP,
4101 .prot = &mptcp_prot,
4102 .ops = &mptcp_stream_ops,
4103 .flags = INET_PROTOSW_ICSK,
4104};
4105
4106static int mptcp_napi_poll(struct napi_struct *napi, int budget)
4107{
4108 struct mptcp_delegated_action *delegated;
4109 struct mptcp_subflow_context *subflow;
4110 int work_done = 0;
4111
4112 delegated = container_of(napi, struct mptcp_delegated_action, napi);
4113 while ((subflow = mptcp_subflow_delegated_next(delegated)) != NULL) {
4114 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
4115
4116 bh_lock_sock_nested(ssk);
4117 if (!sock_owned_by_user(ssk)) {
4118 mptcp_subflow_process_delegated(ssk, xchg(&subflow->delegated_status, 0));
4119 } else {
4120 /* tcp_release_cb_override already processed
4121 * the action or will do at next release_sock().
4122 * In both case must dequeue the subflow here - on the same
4123 * CPU that scheduled it.
4124 */
4125 smp_wmb();
4126 clear_bit(MPTCP_DELEGATE_SCHEDULED, &subflow->delegated_status);
4127 }
4128 bh_unlock_sock(ssk);
4129 sock_put(ssk);
4130
4131 if (++work_done == budget)
4132 return budget;
4133 }
4134
4135 /* always provide a 0 'work_done' argument, so that napi_complete_done
4136 * will not try accessing the NULL napi->dev ptr
4137 */
4138 napi_complete_done(napi, 0);
4139 return work_done;
4140}
4141
4142void __init mptcp_proto_init(void)
4143{
4144 struct mptcp_delegated_action *delegated;
4145 int cpu;
4146
4147 mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo;
4148
4149 if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL))
4150 panic("Failed to allocate MPTCP pcpu counter\n");
4151
4152 init_dummy_netdev(&mptcp_napi_dev);
4153 for_each_possible_cpu(cpu) {
4154 delegated = per_cpu_ptr(&mptcp_delegated_actions, cpu);
4155 INIT_LIST_HEAD(&delegated->head);
4156 netif_napi_add_tx(&mptcp_napi_dev, &delegated->napi,
4157 mptcp_napi_poll);
4158 napi_enable(&delegated->napi);
4159 }
4160
4161 mptcp_subflow_init();
4162 mptcp_pm_init();
4163 mptcp_sched_init();
4164 mptcp_token_init();
4165
4166 if (proto_register(&mptcp_prot, 1) != 0)
4167 panic("Failed to register MPTCP proto.\n");
4168
4169 inet_register_protosw(&mptcp_protosw);
4170
4171 BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb));
4172}
4173
4174#if IS_ENABLED(CONFIG_MPTCP_IPV6)
4175static const struct proto_ops mptcp_v6_stream_ops = {
4176 .family = PF_INET6,
4177 .owner = THIS_MODULE,
4178 .release = inet6_release,
4179 .bind = mptcp_bind,
4180 .connect = inet_stream_connect,
4181 .socketpair = sock_no_socketpair,
4182 .accept = mptcp_stream_accept,
4183 .getname = inet6_getname,
4184 .poll = mptcp_poll,
4185 .ioctl = inet6_ioctl,
4186 .gettstamp = sock_gettstamp,
4187 .listen = mptcp_listen,
4188 .shutdown = inet_shutdown,
4189 .setsockopt = sock_common_setsockopt,
4190 .getsockopt = sock_common_getsockopt,
4191 .sendmsg = inet6_sendmsg,
4192 .recvmsg = inet6_recvmsg,
4193 .mmap = sock_no_mmap,
4194#ifdef CONFIG_COMPAT
4195 .compat_ioctl = inet6_compat_ioctl,
4196#endif
4197 .set_rcvlowat = mptcp_set_rcvlowat,
4198};
4199
4200static struct proto mptcp_v6_prot;
4201
4202static struct inet_protosw mptcp_v6_protosw = {
4203 .type = SOCK_STREAM,
4204 .protocol = IPPROTO_MPTCP,
4205 .prot = &mptcp_v6_prot,
4206 .ops = &mptcp_v6_stream_ops,
4207 .flags = INET_PROTOSW_ICSK,
4208};
4209
4210int __init mptcp_proto_v6_init(void)
4211{
4212 int err;
4213
4214 mptcp_v6_prot = mptcp_prot;
4215 strscpy(mptcp_v6_prot.name, "MPTCPv6", sizeof(mptcp_v6_prot.name));
4216 mptcp_v6_prot.slab = NULL;
4217 mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock);
4218 mptcp_v6_prot.ipv6_pinfo_offset = offsetof(struct mptcp6_sock, np);
4219
4220 err = proto_register(&mptcp_v6_prot, 1);
4221 if (err)
4222 return err;
4223
4224 err = inet6_register_protosw(&mptcp_v6_protosw);
4225 if (err)
4226 proto_unregister(&mptcp_v6_prot);
4227
4228 return err;
4229}
4230#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.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 "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
38struct mptcp_skb_cb {
39 u64 map_seq;
40 u64 end_seq;
41 u32 offset;
42 u8 has_rxtstamp:1;
43};
44
45#define MPTCP_SKB_CB(__skb) ((struct mptcp_skb_cb *)&((__skb)->cb[0]))
46
47enum {
48 MPTCP_CMSG_TS = BIT(0),
49};
50
51static struct percpu_counter mptcp_sockets_allocated;
52
53static void __mptcp_destroy_sock(struct sock *sk);
54static void __mptcp_check_send_data_fin(struct sock *sk);
55
56DEFINE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
57static struct net_device mptcp_napi_dev;
58
59/* If msk has an initial subflow socket, and the MP_CAPABLE handshake has not
60 * completed yet or has failed, return the subflow socket.
61 * Otherwise return NULL.
62 */
63struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk)
64{
65 if (!msk->subflow || READ_ONCE(msk->can_ack))
66 return NULL;
67
68 return msk->subflow;
69}
70
71/* Returns end sequence number of the receiver's advertised window */
72static u64 mptcp_wnd_end(const struct mptcp_sock *msk)
73{
74 return READ_ONCE(msk->wnd_end);
75}
76
77static bool mptcp_is_tcpsk(struct sock *sk)
78{
79 struct socket *sock = sk->sk_socket;
80
81 if (unlikely(sk->sk_prot == &tcp_prot)) {
82 /* we are being invoked after mptcp_accept() has
83 * accepted a non-mp-capable flow: sk is a tcp_sk,
84 * not an mptcp one.
85 *
86 * Hand the socket over to tcp so all further socket ops
87 * bypass mptcp.
88 */
89 sock->ops = &inet_stream_ops;
90 return true;
91#if IS_ENABLED(CONFIG_MPTCP_IPV6)
92 } else if (unlikely(sk->sk_prot == &tcpv6_prot)) {
93 sock->ops = &inet6_stream_ops;
94 return true;
95#endif
96 }
97
98 return false;
99}
100
101static int __mptcp_socket_create(struct mptcp_sock *msk)
102{
103 struct mptcp_subflow_context *subflow;
104 struct sock *sk = (struct sock *)msk;
105 struct socket *ssock;
106 int err;
107
108 err = mptcp_subflow_create_socket(sk, &ssock);
109 if (err)
110 return err;
111
112 msk->first = ssock->sk;
113 msk->subflow = ssock;
114 subflow = mptcp_subflow_ctx(ssock->sk);
115 list_add(&subflow->node, &msk->conn_list);
116 sock_hold(ssock->sk);
117 subflow->request_mptcp = 1;
118 mptcp_sock_graft(msk->first, sk->sk_socket);
119
120 return 0;
121}
122
123static void mptcp_drop(struct sock *sk, struct sk_buff *skb)
124{
125 sk_drops_add(sk, skb);
126 __kfree_skb(skb);
127}
128
129static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to,
130 struct sk_buff *from)
131{
132 bool fragstolen;
133 int delta;
134
135 if (MPTCP_SKB_CB(from)->offset ||
136 !skb_try_coalesce(to, from, &fragstolen, &delta))
137 return false;
138
139 pr_debug("colesced seq %llx into %llx new len %d new end seq %llx",
140 MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq,
141 to->len, MPTCP_SKB_CB(from)->end_seq);
142 MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq;
143 kfree_skb_partial(from, fragstolen);
144 atomic_add(delta, &sk->sk_rmem_alloc);
145 sk_mem_charge(sk, delta);
146 return true;
147}
148
149static bool mptcp_ooo_try_coalesce(struct mptcp_sock *msk, struct sk_buff *to,
150 struct sk_buff *from)
151{
152 if (MPTCP_SKB_CB(from)->map_seq != MPTCP_SKB_CB(to)->end_seq)
153 return false;
154
155 return mptcp_try_coalesce((struct sock *)msk, to, from);
156}
157
158/* "inspired" by tcp_data_queue_ofo(), main differences:
159 * - use mptcp seqs
160 * - don't cope with sacks
161 */
162static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb)
163{
164 struct sock *sk = (struct sock *)msk;
165 struct rb_node **p, *parent;
166 u64 seq, end_seq, max_seq;
167 struct sk_buff *skb1;
168
169 seq = MPTCP_SKB_CB(skb)->map_seq;
170 end_seq = MPTCP_SKB_CB(skb)->end_seq;
171 max_seq = READ_ONCE(msk->rcv_wnd_sent);
172
173 pr_debug("msk=%p seq=%llx limit=%llx empty=%d", msk, seq, max_seq,
174 RB_EMPTY_ROOT(&msk->out_of_order_queue));
175 if (after64(end_seq, max_seq)) {
176 /* out of window */
177 mptcp_drop(sk, skb);
178 pr_debug("oow by %lld, rcv_wnd_sent %llu\n",
179 (unsigned long long)end_seq - (unsigned long)max_seq,
180 (unsigned long long)msk->rcv_wnd_sent);
181 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_NODSSWINDOW);
182 return;
183 }
184
185 p = &msk->out_of_order_queue.rb_node;
186 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUE);
187 if (RB_EMPTY_ROOT(&msk->out_of_order_queue)) {
188 rb_link_node(&skb->rbnode, NULL, p);
189 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
190 msk->ooo_last_skb = skb;
191 goto end;
192 }
193
194 /* with 2 subflows, adding at end of ooo queue is quite likely
195 * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup.
196 */
197 if (mptcp_ooo_try_coalesce(msk, msk->ooo_last_skb, skb)) {
198 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
199 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
200 return;
201 }
202
203 /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */
204 if (!before64(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) {
205 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
206 parent = &msk->ooo_last_skb->rbnode;
207 p = &parent->rb_right;
208 goto insert;
209 }
210
211 /* Find place to insert this segment. Handle overlaps on the way. */
212 parent = NULL;
213 while (*p) {
214 parent = *p;
215 skb1 = rb_to_skb(parent);
216 if (before64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
217 p = &parent->rb_left;
218 continue;
219 }
220 if (before64(seq, MPTCP_SKB_CB(skb1)->end_seq)) {
221 if (!after64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) {
222 /* All the bits are present. Drop. */
223 mptcp_drop(sk, skb);
224 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
225 return;
226 }
227 if (after64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
228 /* partial overlap:
229 * | skb |
230 * | skb1 |
231 * continue traversing
232 */
233 } else {
234 /* skb's seq == skb1's seq and skb covers skb1.
235 * Replace skb1 with skb.
236 */
237 rb_replace_node(&skb1->rbnode, &skb->rbnode,
238 &msk->out_of_order_queue);
239 mptcp_drop(sk, skb1);
240 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
241 goto merge_right;
242 }
243 } else if (mptcp_ooo_try_coalesce(msk, skb1, skb)) {
244 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
245 return;
246 }
247 p = &parent->rb_right;
248 }
249
250insert:
251 /* Insert segment into RB tree. */
252 rb_link_node(&skb->rbnode, parent, p);
253 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
254
255merge_right:
256 /* Remove other segments covered by skb. */
257 while ((skb1 = skb_rb_next(skb)) != NULL) {
258 if (before64(end_seq, MPTCP_SKB_CB(skb1)->end_seq))
259 break;
260 rb_erase(&skb1->rbnode, &msk->out_of_order_queue);
261 mptcp_drop(sk, skb1);
262 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
263 }
264 /* If there is no skb after us, we are the last_skb ! */
265 if (!skb1)
266 msk->ooo_last_skb = skb;
267
268end:
269 skb_condense(skb);
270 skb_set_owner_r(skb, sk);
271}
272
273static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk,
274 struct sk_buff *skb, unsigned int offset,
275 size_t copy_len)
276{
277 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
278 struct sock *sk = (struct sock *)msk;
279 struct sk_buff *tail;
280 bool has_rxtstamp;
281
282 __skb_unlink(skb, &ssk->sk_receive_queue);
283
284 skb_ext_reset(skb);
285 skb_orphan(skb);
286
287 /* try to fetch required memory from subflow */
288 if (!sk_rmem_schedule(sk, skb, skb->truesize)) {
289 int amount = sk_mem_pages(skb->truesize) << SK_MEM_QUANTUM_SHIFT;
290
291 if (ssk->sk_forward_alloc < amount)
292 goto drop;
293
294 ssk->sk_forward_alloc -= amount;
295 sk->sk_forward_alloc += amount;
296 }
297
298 has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp;
299
300 /* the skb map_seq accounts for the skb offset:
301 * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq
302 * value
303 */
304 MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow);
305 MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len;
306 MPTCP_SKB_CB(skb)->offset = offset;
307 MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp;
308
309 if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) {
310 /* in sequence */
311 WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len);
312 tail = skb_peek_tail(&sk->sk_receive_queue);
313 if (tail && mptcp_try_coalesce(sk, tail, skb))
314 return true;
315
316 skb_set_owner_r(skb, sk);
317 __skb_queue_tail(&sk->sk_receive_queue, skb);
318 return true;
319 } else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) {
320 mptcp_data_queue_ofo(msk, skb);
321 return false;
322 }
323
324 /* old data, keep it simple and drop the whole pkt, sender
325 * will retransmit as needed, if needed.
326 */
327 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
328drop:
329 mptcp_drop(sk, skb);
330 return false;
331}
332
333static void mptcp_stop_timer(struct sock *sk)
334{
335 struct inet_connection_sock *icsk = inet_csk(sk);
336
337 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
338 mptcp_sk(sk)->timer_ival = 0;
339}
340
341static void mptcp_close_wake_up(struct sock *sk)
342{
343 if (sock_flag(sk, SOCK_DEAD))
344 return;
345
346 sk->sk_state_change(sk);
347 if (sk->sk_shutdown == SHUTDOWN_MASK ||
348 sk->sk_state == TCP_CLOSE)
349 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
350 else
351 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
352}
353
354static bool mptcp_pending_data_fin_ack(struct sock *sk)
355{
356 struct mptcp_sock *msk = mptcp_sk(sk);
357
358 return !__mptcp_check_fallback(msk) &&
359 ((1 << sk->sk_state) &
360 (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) &&
361 msk->write_seq == READ_ONCE(msk->snd_una);
362}
363
364static void mptcp_check_data_fin_ack(struct sock *sk)
365{
366 struct mptcp_sock *msk = mptcp_sk(sk);
367
368 /* Look for an acknowledged DATA_FIN */
369 if (mptcp_pending_data_fin_ack(sk)) {
370 WRITE_ONCE(msk->snd_data_fin_enable, 0);
371
372 switch (sk->sk_state) {
373 case TCP_FIN_WAIT1:
374 inet_sk_state_store(sk, TCP_FIN_WAIT2);
375 break;
376 case TCP_CLOSING:
377 case TCP_LAST_ACK:
378 inet_sk_state_store(sk, TCP_CLOSE);
379 break;
380 }
381
382 mptcp_close_wake_up(sk);
383 }
384}
385
386static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq)
387{
388 struct mptcp_sock *msk = mptcp_sk(sk);
389
390 if (READ_ONCE(msk->rcv_data_fin) &&
391 ((1 << sk->sk_state) &
392 (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) {
393 u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq);
394
395 if (msk->ack_seq == rcv_data_fin_seq) {
396 if (seq)
397 *seq = rcv_data_fin_seq;
398
399 return true;
400 }
401 }
402
403 return false;
404}
405
406static void mptcp_set_datafin_timeout(const struct sock *sk)
407{
408 struct inet_connection_sock *icsk = inet_csk(sk);
409
410 mptcp_sk(sk)->timer_ival = min(TCP_RTO_MAX,
411 TCP_RTO_MIN << icsk->icsk_retransmits);
412}
413
414static void mptcp_set_timeout(const struct sock *sk, const struct sock *ssk)
415{
416 long tout = ssk && inet_csk(ssk)->icsk_pending ?
417 inet_csk(ssk)->icsk_timeout - jiffies : 0;
418
419 if (tout <= 0)
420 tout = mptcp_sk(sk)->timer_ival;
421 mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
422}
423
424static bool tcp_can_send_ack(const struct sock *ssk)
425{
426 return !((1 << inet_sk_state_load(ssk)) &
427 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE | TCPF_LISTEN));
428}
429
430void mptcp_subflow_send_ack(struct sock *ssk)
431{
432 bool slow;
433
434 slow = lock_sock_fast(ssk);
435 if (tcp_can_send_ack(ssk))
436 tcp_send_ack(ssk);
437 unlock_sock_fast(ssk, slow);
438}
439
440static void mptcp_send_ack(struct mptcp_sock *msk)
441{
442 struct mptcp_subflow_context *subflow;
443
444 mptcp_for_each_subflow(msk, subflow)
445 mptcp_subflow_send_ack(mptcp_subflow_tcp_sock(subflow));
446}
447
448static void mptcp_subflow_cleanup_rbuf(struct sock *ssk)
449{
450 bool slow;
451
452 slow = lock_sock_fast(ssk);
453 if (tcp_can_send_ack(ssk))
454 tcp_cleanup_rbuf(ssk, 1);
455 unlock_sock_fast(ssk, slow);
456}
457
458static bool mptcp_subflow_could_cleanup(const struct sock *ssk, bool rx_empty)
459{
460 const struct inet_connection_sock *icsk = inet_csk(ssk);
461 u8 ack_pending = READ_ONCE(icsk->icsk_ack.pending);
462 const struct tcp_sock *tp = tcp_sk(ssk);
463
464 return (ack_pending & ICSK_ACK_SCHED) &&
465 ((READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->rcv_wup) >
466 READ_ONCE(icsk->icsk_ack.rcv_mss)) ||
467 (rx_empty && ack_pending &
468 (ICSK_ACK_PUSHED2 | ICSK_ACK_PUSHED)));
469}
470
471static void mptcp_cleanup_rbuf(struct mptcp_sock *msk)
472{
473 int old_space = READ_ONCE(msk->old_wspace);
474 struct mptcp_subflow_context *subflow;
475 struct sock *sk = (struct sock *)msk;
476 int space = __mptcp_space(sk);
477 bool cleanup, rx_empty;
478
479 cleanup = (space > 0) && (space >= (old_space << 1));
480 rx_empty = !__mptcp_rmem(sk);
481
482 mptcp_for_each_subflow(msk, subflow) {
483 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
484
485 if (cleanup || mptcp_subflow_could_cleanup(ssk, rx_empty))
486 mptcp_subflow_cleanup_rbuf(ssk);
487 }
488}
489
490static bool mptcp_check_data_fin(struct sock *sk)
491{
492 struct mptcp_sock *msk = mptcp_sk(sk);
493 u64 rcv_data_fin_seq;
494 bool ret = false;
495
496 if (__mptcp_check_fallback(msk))
497 return ret;
498
499 /* Need to ack a DATA_FIN received from a peer while this side
500 * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2.
501 * msk->rcv_data_fin was set when parsing the incoming options
502 * at the subflow level and the msk lock was not held, so this
503 * is the first opportunity to act on the DATA_FIN and change
504 * the msk state.
505 *
506 * If we are caught up to the sequence number of the incoming
507 * DATA_FIN, send the DATA_ACK now and do state transition. If
508 * not caught up, do nothing and let the recv code send DATA_ACK
509 * when catching up.
510 */
511
512 if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) {
513 WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1);
514 WRITE_ONCE(msk->rcv_data_fin, 0);
515
516 sk->sk_shutdown |= RCV_SHUTDOWN;
517 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
518
519 switch (sk->sk_state) {
520 case TCP_ESTABLISHED:
521 inet_sk_state_store(sk, TCP_CLOSE_WAIT);
522 break;
523 case TCP_FIN_WAIT1:
524 inet_sk_state_store(sk, TCP_CLOSING);
525 break;
526 case TCP_FIN_WAIT2:
527 inet_sk_state_store(sk, TCP_CLOSE);
528 break;
529 default:
530 /* Other states not expected */
531 WARN_ON_ONCE(1);
532 break;
533 }
534
535 ret = true;
536 mptcp_set_timeout(sk, NULL);
537 mptcp_send_ack(msk);
538 mptcp_close_wake_up(sk);
539 }
540 return ret;
541}
542
543static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
544 struct sock *ssk,
545 unsigned int *bytes)
546{
547 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
548 struct sock *sk = (struct sock *)msk;
549 unsigned int moved = 0;
550 bool more_data_avail;
551 struct tcp_sock *tp;
552 bool done = false;
553 int sk_rbuf;
554
555 sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
556
557 if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
558 int ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
559
560 if (unlikely(ssk_rbuf > sk_rbuf)) {
561 WRITE_ONCE(sk->sk_rcvbuf, ssk_rbuf);
562 sk_rbuf = ssk_rbuf;
563 }
564 }
565
566 pr_debug("msk=%p ssk=%p", msk, ssk);
567 tp = tcp_sk(ssk);
568 do {
569 u32 map_remaining, offset;
570 u32 seq = tp->copied_seq;
571 struct sk_buff *skb;
572 bool fin;
573
574 /* try to move as much data as available */
575 map_remaining = subflow->map_data_len -
576 mptcp_subflow_get_map_offset(subflow);
577
578 skb = skb_peek(&ssk->sk_receive_queue);
579 if (!skb) {
580 /* if no data is found, a racing workqueue/recvmsg
581 * already processed the new data, stop here or we
582 * can enter an infinite loop
583 */
584 if (!moved)
585 done = true;
586 break;
587 }
588
589 if (__mptcp_check_fallback(msk)) {
590 /* if we are running under the workqueue, TCP could have
591 * collapsed skbs between dummy map creation and now
592 * be sure to adjust the size
593 */
594 map_remaining = skb->len;
595 subflow->map_data_len = skb->len;
596 }
597
598 offset = seq - TCP_SKB_CB(skb)->seq;
599 fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
600 if (fin) {
601 done = true;
602 seq++;
603 }
604
605 if (offset < skb->len) {
606 size_t len = skb->len - offset;
607
608 if (tp->urg_data)
609 done = true;
610
611 if (__mptcp_move_skb(msk, ssk, skb, offset, len))
612 moved += len;
613 seq += len;
614
615 if (WARN_ON_ONCE(map_remaining < len))
616 break;
617 } else {
618 WARN_ON_ONCE(!fin);
619 sk_eat_skb(ssk, skb);
620 done = true;
621 }
622
623 WRITE_ONCE(tp->copied_seq, seq);
624 more_data_avail = mptcp_subflow_data_available(ssk);
625
626 if (atomic_read(&sk->sk_rmem_alloc) > sk_rbuf) {
627 done = true;
628 break;
629 }
630 } while (more_data_avail);
631
632 *bytes += moved;
633 return done;
634}
635
636static bool __mptcp_ofo_queue(struct mptcp_sock *msk)
637{
638 struct sock *sk = (struct sock *)msk;
639 struct sk_buff *skb, *tail;
640 bool moved = false;
641 struct rb_node *p;
642 u64 end_seq;
643
644 p = rb_first(&msk->out_of_order_queue);
645 pr_debug("msk=%p empty=%d", msk, RB_EMPTY_ROOT(&msk->out_of_order_queue));
646 while (p) {
647 skb = rb_to_skb(p);
648 if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq))
649 break;
650
651 p = rb_next(p);
652 rb_erase(&skb->rbnode, &msk->out_of_order_queue);
653
654 if (unlikely(!after64(MPTCP_SKB_CB(skb)->end_seq,
655 msk->ack_seq))) {
656 mptcp_drop(sk, skb);
657 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
658 continue;
659 }
660
661 end_seq = MPTCP_SKB_CB(skb)->end_seq;
662 tail = skb_peek_tail(&sk->sk_receive_queue);
663 if (!tail || !mptcp_ooo_try_coalesce(msk, tail, skb)) {
664 int delta = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq;
665
666 /* skip overlapping data, if any */
667 pr_debug("uncoalesced seq=%llx ack seq=%llx delta=%d",
668 MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq,
669 delta);
670 MPTCP_SKB_CB(skb)->offset += delta;
671 __skb_queue_tail(&sk->sk_receive_queue, skb);
672 }
673 msk->ack_seq = end_seq;
674 moved = true;
675 }
676 return moved;
677}
678
679/* In most cases we will be able to lock the mptcp socket. If its already
680 * owned, we need to defer to the work queue to avoid ABBA deadlock.
681 */
682static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk)
683{
684 struct sock *sk = (struct sock *)msk;
685 unsigned int moved = 0;
686
687 __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
688 __mptcp_ofo_queue(msk);
689 if (unlikely(ssk->sk_err)) {
690 if (!sock_owned_by_user(sk))
691 __mptcp_error_report(sk);
692 else
693 set_bit(MPTCP_ERROR_REPORT, &msk->flags);
694 }
695
696 /* If the moves have caught up with the DATA_FIN sequence number
697 * it's time to ack the DATA_FIN and change socket state, but
698 * this is not a good place to change state. Let the workqueue
699 * do it.
700 */
701 if (mptcp_pending_data_fin(sk, NULL))
702 mptcp_schedule_work(sk);
703 return moved > 0;
704}
705
706void mptcp_data_ready(struct sock *sk, struct sock *ssk)
707{
708 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
709 struct mptcp_sock *msk = mptcp_sk(sk);
710 int sk_rbuf, ssk_rbuf;
711
712 /* The peer can send data while we are shutting down this
713 * subflow at msk destruction time, but we must avoid enqueuing
714 * more data to the msk receive queue
715 */
716 if (unlikely(subflow->disposable))
717 return;
718
719 ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
720 sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
721 if (unlikely(ssk_rbuf > sk_rbuf))
722 sk_rbuf = ssk_rbuf;
723
724 /* over limit? can't append more skbs to msk, Also, no need to wake-up*/
725 if (__mptcp_rmem(sk) > sk_rbuf) {
726 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED);
727 return;
728 }
729
730 /* Wake-up the reader only for in-sequence data */
731 mptcp_data_lock(sk);
732 if (move_skbs_to_msk(msk, ssk))
733 sk->sk_data_ready(sk);
734
735 mptcp_data_unlock(sk);
736}
737
738static bool mptcp_do_flush_join_list(struct mptcp_sock *msk)
739{
740 struct mptcp_subflow_context *subflow;
741 bool ret = false;
742
743 if (likely(list_empty(&msk->join_list)))
744 return false;
745
746 spin_lock_bh(&msk->join_list_lock);
747 list_for_each_entry(subflow, &msk->join_list, node) {
748 u32 sseq = READ_ONCE(subflow->setsockopt_seq);
749
750 mptcp_propagate_sndbuf((struct sock *)msk, mptcp_subflow_tcp_sock(subflow));
751 if (READ_ONCE(msk->setsockopt_seq) != sseq)
752 ret = true;
753 }
754 list_splice_tail_init(&msk->join_list, &msk->conn_list);
755 spin_unlock_bh(&msk->join_list_lock);
756
757 return ret;
758}
759
760void __mptcp_flush_join_list(struct mptcp_sock *msk)
761{
762 if (likely(!mptcp_do_flush_join_list(msk)))
763 return;
764
765 if (!test_and_set_bit(MPTCP_WORK_SYNC_SETSOCKOPT, &msk->flags))
766 mptcp_schedule_work((struct sock *)msk);
767}
768
769static void mptcp_flush_join_list(struct mptcp_sock *msk)
770{
771 bool sync_needed = test_and_clear_bit(MPTCP_WORK_SYNC_SETSOCKOPT, &msk->flags);
772
773 might_sleep();
774
775 if (!mptcp_do_flush_join_list(msk) && !sync_needed)
776 return;
777
778 mptcp_sockopt_sync_all(msk);
779}
780
781static bool mptcp_timer_pending(struct sock *sk)
782{
783 return timer_pending(&inet_csk(sk)->icsk_retransmit_timer);
784}
785
786static void mptcp_reset_timer(struct sock *sk)
787{
788 struct inet_connection_sock *icsk = inet_csk(sk);
789 unsigned long tout;
790
791 /* prevent rescheduling on close */
792 if (unlikely(inet_sk_state_load(sk) == TCP_CLOSE))
793 return;
794
795 /* should never be called with mptcp level timer cleared */
796 tout = READ_ONCE(mptcp_sk(sk)->timer_ival);
797 if (WARN_ON_ONCE(!tout))
798 tout = TCP_RTO_MIN;
799 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout);
800}
801
802bool mptcp_schedule_work(struct sock *sk)
803{
804 if (inet_sk_state_load(sk) != TCP_CLOSE &&
805 schedule_work(&mptcp_sk(sk)->work)) {
806 /* each subflow already holds a reference to the sk, and the
807 * workqueue is invoked by a subflow, so sk can't go away here.
808 */
809 sock_hold(sk);
810 return true;
811 }
812 return false;
813}
814
815void mptcp_subflow_eof(struct sock *sk)
816{
817 if (!test_and_set_bit(MPTCP_WORK_EOF, &mptcp_sk(sk)->flags))
818 mptcp_schedule_work(sk);
819}
820
821static void mptcp_check_for_eof(struct mptcp_sock *msk)
822{
823 struct mptcp_subflow_context *subflow;
824 struct sock *sk = (struct sock *)msk;
825 int receivers = 0;
826
827 mptcp_for_each_subflow(msk, subflow)
828 receivers += !subflow->rx_eof;
829 if (receivers)
830 return;
831
832 if (!(sk->sk_shutdown & RCV_SHUTDOWN)) {
833 /* hopefully temporary hack: propagate shutdown status
834 * to msk, when all subflows agree on it
835 */
836 sk->sk_shutdown |= RCV_SHUTDOWN;
837
838 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
839 sk->sk_data_ready(sk);
840 }
841
842 switch (sk->sk_state) {
843 case TCP_ESTABLISHED:
844 inet_sk_state_store(sk, TCP_CLOSE_WAIT);
845 break;
846 case TCP_FIN_WAIT1:
847 inet_sk_state_store(sk, TCP_CLOSING);
848 break;
849 case TCP_FIN_WAIT2:
850 inet_sk_state_store(sk, TCP_CLOSE);
851 break;
852 default:
853 return;
854 }
855 mptcp_close_wake_up(sk);
856}
857
858static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk)
859{
860 struct mptcp_subflow_context *subflow;
861 struct sock *sk = (struct sock *)msk;
862
863 sock_owned_by_me(sk);
864
865 mptcp_for_each_subflow(msk, subflow) {
866 if (READ_ONCE(subflow->data_avail))
867 return mptcp_subflow_tcp_sock(subflow);
868 }
869
870 return NULL;
871}
872
873static bool mptcp_skb_can_collapse_to(u64 write_seq,
874 const struct sk_buff *skb,
875 const struct mptcp_ext *mpext)
876{
877 if (!tcp_skb_can_collapse_to(skb))
878 return false;
879
880 /* can collapse only if MPTCP level sequence is in order and this
881 * mapping has not been xmitted yet
882 */
883 return mpext && mpext->data_seq + mpext->data_len == write_seq &&
884 !mpext->frozen;
885}
886
887/* we can append data to the given data frag if:
888 * - there is space available in the backing page_frag
889 * - the data frag tail matches the current page_frag free offset
890 * - the data frag end sequence number matches the current write seq
891 */
892static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk,
893 const struct page_frag *pfrag,
894 const struct mptcp_data_frag *df)
895{
896 return df && pfrag->page == df->page &&
897 pfrag->size - pfrag->offset > 0 &&
898 pfrag->offset == (df->offset + df->data_len) &&
899 df->data_seq + df->data_len == msk->write_seq;
900}
901
902static int mptcp_wmem_with_overhead(int size)
903{
904 return size + ((sizeof(struct mptcp_data_frag) * size) >> PAGE_SHIFT);
905}
906
907static void __mptcp_wmem_reserve(struct sock *sk, int size)
908{
909 int amount = mptcp_wmem_with_overhead(size);
910 struct mptcp_sock *msk = mptcp_sk(sk);
911
912 WARN_ON_ONCE(msk->wmem_reserved);
913 if (WARN_ON_ONCE(amount < 0))
914 amount = 0;
915
916 if (amount <= sk->sk_forward_alloc)
917 goto reserve;
918
919 /* under memory pressure try to reserve at most a single page
920 * otherwise try to reserve the full estimate and fallback
921 * to a single page before entering the error path
922 */
923 if ((tcp_under_memory_pressure(sk) && amount > PAGE_SIZE) ||
924 !sk_wmem_schedule(sk, amount)) {
925 if (amount <= PAGE_SIZE)
926 goto nomem;
927
928 amount = PAGE_SIZE;
929 if (!sk_wmem_schedule(sk, amount))
930 goto nomem;
931 }
932
933reserve:
934 msk->wmem_reserved = amount;
935 sk->sk_forward_alloc -= amount;
936 return;
937
938nomem:
939 /* we will wait for memory on next allocation */
940 msk->wmem_reserved = -1;
941}
942
943static void __mptcp_update_wmem(struct sock *sk)
944{
945 struct mptcp_sock *msk = mptcp_sk(sk);
946
947#ifdef CONFIG_LOCKDEP
948 WARN_ON_ONCE(!lockdep_is_held(&sk->sk_lock.slock));
949#endif
950
951 if (!msk->wmem_reserved)
952 return;
953
954 if (msk->wmem_reserved < 0)
955 msk->wmem_reserved = 0;
956 if (msk->wmem_reserved > 0) {
957 sk->sk_forward_alloc += msk->wmem_reserved;
958 msk->wmem_reserved = 0;
959 }
960}
961
962static bool mptcp_wmem_alloc(struct sock *sk, int size)
963{
964 struct mptcp_sock *msk = mptcp_sk(sk);
965
966 /* check for pre-existing error condition */
967 if (msk->wmem_reserved < 0)
968 return false;
969
970 if (msk->wmem_reserved >= size)
971 goto account;
972
973 mptcp_data_lock(sk);
974 if (!sk_wmem_schedule(sk, size)) {
975 mptcp_data_unlock(sk);
976 return false;
977 }
978
979 sk->sk_forward_alloc -= size;
980 msk->wmem_reserved += size;
981 mptcp_data_unlock(sk);
982
983account:
984 msk->wmem_reserved -= size;
985 return true;
986}
987
988static void mptcp_wmem_uncharge(struct sock *sk, int size)
989{
990 struct mptcp_sock *msk = mptcp_sk(sk);
991
992 if (msk->wmem_reserved < 0)
993 msk->wmem_reserved = 0;
994 msk->wmem_reserved += size;
995}
996
997static void __mptcp_mem_reclaim_partial(struct sock *sk)
998{
999 lockdep_assert_held_once(&sk->sk_lock.slock);
1000 __mptcp_update_wmem(sk);
1001 sk_mem_reclaim_partial(sk);
1002}
1003
1004static void mptcp_mem_reclaim_partial(struct sock *sk)
1005{
1006 struct mptcp_sock *msk = mptcp_sk(sk);
1007
1008 /* if we are experiencing a transint allocation error,
1009 * the forward allocation memory has been already
1010 * released
1011 */
1012 if (msk->wmem_reserved < 0)
1013 return;
1014
1015 mptcp_data_lock(sk);
1016 sk->sk_forward_alloc += msk->wmem_reserved;
1017 sk_mem_reclaim_partial(sk);
1018 msk->wmem_reserved = sk->sk_forward_alloc;
1019 sk->sk_forward_alloc = 0;
1020 mptcp_data_unlock(sk);
1021}
1022
1023static void dfrag_uncharge(struct sock *sk, int len)
1024{
1025 sk_mem_uncharge(sk, len);
1026 sk_wmem_queued_add(sk, -len);
1027}
1028
1029static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag)
1030{
1031 int len = dfrag->data_len + dfrag->overhead;
1032
1033 list_del(&dfrag->list);
1034 dfrag_uncharge(sk, len);
1035 put_page(dfrag->page);
1036}
1037
1038static void __mptcp_clean_una(struct sock *sk)
1039{
1040 struct mptcp_sock *msk = mptcp_sk(sk);
1041 struct mptcp_data_frag *dtmp, *dfrag;
1042 bool cleaned = false;
1043 u64 snd_una;
1044
1045 /* on fallback we just need to ignore snd_una, as this is really
1046 * plain TCP
1047 */
1048 if (__mptcp_check_fallback(msk))
1049 msk->snd_una = READ_ONCE(msk->snd_nxt);
1050
1051 snd_una = msk->snd_una;
1052 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) {
1053 if (after64(dfrag->data_seq + dfrag->data_len, snd_una))
1054 break;
1055
1056 if (WARN_ON_ONCE(dfrag == msk->first_pending))
1057 break;
1058 dfrag_clear(sk, dfrag);
1059 cleaned = true;
1060 }
1061
1062 dfrag = mptcp_rtx_head(sk);
1063 if (dfrag && after64(snd_una, dfrag->data_seq)) {
1064 u64 delta = snd_una - dfrag->data_seq;
1065
1066 if (WARN_ON_ONCE(delta > dfrag->already_sent))
1067 goto out;
1068
1069 dfrag->data_seq += delta;
1070 dfrag->offset += delta;
1071 dfrag->data_len -= delta;
1072 dfrag->already_sent -= delta;
1073
1074 dfrag_uncharge(sk, delta);
1075 cleaned = true;
1076 }
1077
1078out:
1079 if (cleaned && tcp_under_memory_pressure(sk))
1080 __mptcp_mem_reclaim_partial(sk);
1081
1082 if (snd_una == READ_ONCE(msk->snd_nxt)) {
1083 if (msk->timer_ival && !mptcp_data_fin_enabled(msk))
1084 mptcp_stop_timer(sk);
1085 } else {
1086 mptcp_reset_timer(sk);
1087 }
1088}
1089
1090static void __mptcp_clean_una_wakeup(struct sock *sk)
1091{
1092#ifdef CONFIG_LOCKDEP
1093 WARN_ON_ONCE(!lockdep_is_held(&sk->sk_lock.slock));
1094#endif
1095 __mptcp_clean_una(sk);
1096 mptcp_write_space(sk);
1097}
1098
1099static void mptcp_clean_una_wakeup(struct sock *sk)
1100{
1101 mptcp_data_lock(sk);
1102 __mptcp_clean_una_wakeup(sk);
1103 mptcp_data_unlock(sk);
1104}
1105
1106static void mptcp_enter_memory_pressure(struct sock *sk)
1107{
1108 struct mptcp_subflow_context *subflow;
1109 struct mptcp_sock *msk = mptcp_sk(sk);
1110 bool first = true;
1111
1112 sk_stream_moderate_sndbuf(sk);
1113 mptcp_for_each_subflow(msk, subflow) {
1114 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
1115
1116 if (first)
1117 tcp_enter_memory_pressure(ssk);
1118 sk_stream_moderate_sndbuf(ssk);
1119 first = false;
1120 }
1121}
1122
1123/* ensure we get enough memory for the frag hdr, beyond some minimal amount of
1124 * data
1125 */
1126static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag)
1127{
1128 if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag),
1129 pfrag, sk->sk_allocation)))
1130 return true;
1131
1132 mptcp_enter_memory_pressure(sk);
1133 return false;
1134}
1135
1136static struct mptcp_data_frag *
1137mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag,
1138 int orig_offset)
1139{
1140 int offset = ALIGN(orig_offset, sizeof(long));
1141 struct mptcp_data_frag *dfrag;
1142
1143 dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset);
1144 dfrag->data_len = 0;
1145 dfrag->data_seq = msk->write_seq;
1146 dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag);
1147 dfrag->offset = offset + sizeof(struct mptcp_data_frag);
1148 dfrag->already_sent = 0;
1149 dfrag->page = pfrag->page;
1150
1151 return dfrag;
1152}
1153
1154struct mptcp_sendmsg_info {
1155 int mss_now;
1156 int size_goal;
1157 u16 limit;
1158 u16 sent;
1159 unsigned int flags;
1160 bool data_lock_held;
1161};
1162
1163static int mptcp_check_allowed_size(struct mptcp_sock *msk, u64 data_seq,
1164 int avail_size)
1165{
1166 u64 window_end = mptcp_wnd_end(msk);
1167
1168 if (__mptcp_check_fallback(msk))
1169 return avail_size;
1170
1171 if (!before64(data_seq + avail_size, window_end)) {
1172 u64 allowed_size = window_end - data_seq;
1173
1174 return min_t(unsigned int, allowed_size, avail_size);
1175 }
1176
1177 return avail_size;
1178}
1179
1180static bool __mptcp_add_ext(struct sk_buff *skb, gfp_t gfp)
1181{
1182 struct skb_ext *mpext = __skb_ext_alloc(gfp);
1183
1184 if (!mpext)
1185 return false;
1186 __skb_ext_set(skb, SKB_EXT_MPTCP, mpext);
1187 return true;
1188}
1189
1190static struct sk_buff *__mptcp_do_alloc_tx_skb(struct sock *sk, gfp_t gfp)
1191{
1192 struct sk_buff *skb;
1193
1194 skb = alloc_skb_fclone(MAX_TCP_HEADER, gfp);
1195 if (likely(skb)) {
1196 if (likely(__mptcp_add_ext(skb, gfp))) {
1197 skb_reserve(skb, MAX_TCP_HEADER);
1198 skb->reserved_tailroom = skb->end - skb->tail;
1199 return skb;
1200 }
1201 __kfree_skb(skb);
1202 } else {
1203 mptcp_enter_memory_pressure(sk);
1204 }
1205 return NULL;
1206}
1207
1208static bool __mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, gfp_t gfp)
1209{
1210 struct sk_buff *skb;
1211
1212 if (ssk->sk_tx_skb_cache) {
1213 skb = ssk->sk_tx_skb_cache;
1214 if (unlikely(!skb_ext_find(skb, SKB_EXT_MPTCP) &&
1215 !__mptcp_add_ext(skb, gfp)))
1216 return false;
1217 return true;
1218 }
1219
1220 skb = __mptcp_do_alloc_tx_skb(sk, gfp);
1221 if (!skb)
1222 return false;
1223
1224 if (likely(sk_wmem_schedule(ssk, skb->truesize))) {
1225 ssk->sk_tx_skb_cache = skb;
1226 return true;
1227 }
1228 kfree_skb(skb);
1229 return false;
1230}
1231
1232static bool mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, bool data_lock_held)
1233{
1234 gfp_t gfp = data_lock_held ? GFP_ATOMIC : sk->sk_allocation;
1235
1236 if (unlikely(tcp_under_memory_pressure(sk))) {
1237 if (data_lock_held)
1238 __mptcp_mem_reclaim_partial(sk);
1239 else
1240 mptcp_mem_reclaim_partial(sk);
1241 }
1242 return __mptcp_alloc_tx_skb(sk, ssk, gfp);
1243}
1244
1245/* note: this always recompute the csum on the whole skb, even
1246 * if we just appended a single frag. More status info needed
1247 */
1248static void mptcp_update_data_checksum(struct sk_buff *skb, int added)
1249{
1250 struct mptcp_ext *mpext = mptcp_get_ext(skb);
1251 __wsum csum = ~csum_unfold(mpext->csum);
1252 int offset = skb->len - added;
1253
1254 mpext->csum = csum_fold(csum_block_add(csum, skb_checksum(skb, offset, added, 0), offset));
1255}
1256
1257static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
1258 struct mptcp_data_frag *dfrag,
1259 struct mptcp_sendmsg_info *info)
1260{
1261 u64 data_seq = dfrag->data_seq + info->sent;
1262 struct mptcp_sock *msk = mptcp_sk(sk);
1263 bool zero_window_probe = false;
1264 struct mptcp_ext *mpext = NULL;
1265 struct sk_buff *skb, *tail;
1266 bool must_collapse = false;
1267 int size_bias = 0;
1268 int avail_size;
1269 size_t ret = 0;
1270
1271 pr_debug("msk=%p ssk=%p sending dfrag at seq=%llu len=%u already sent=%u",
1272 msk, ssk, dfrag->data_seq, dfrag->data_len, info->sent);
1273
1274 /* compute send limit */
1275 info->mss_now = tcp_send_mss(ssk, &info->size_goal, info->flags);
1276 avail_size = info->size_goal;
1277 skb = tcp_write_queue_tail(ssk);
1278 if (skb) {
1279 /* Limit the write to the size available in the
1280 * current skb, if any, so that we create at most a new skb.
1281 * Explicitly tells TCP internals to avoid collapsing on later
1282 * queue management operation, to avoid breaking the ext <->
1283 * SSN association set here
1284 */
1285 mpext = skb_ext_find(skb, SKB_EXT_MPTCP);
1286 if (!mptcp_skb_can_collapse_to(data_seq, skb, mpext)) {
1287 TCP_SKB_CB(skb)->eor = 1;
1288 goto alloc_skb;
1289 }
1290
1291 must_collapse = (info->size_goal > skb->len) &&
1292 (skb_shinfo(skb)->nr_frags < sysctl_max_skb_frags);
1293 if (must_collapse) {
1294 size_bias = skb->len;
1295 avail_size = info->size_goal - skb->len;
1296 }
1297 }
1298
1299alloc_skb:
1300 if (!must_collapse &&
1301 !mptcp_alloc_tx_skb(sk, ssk, info->data_lock_held))
1302 return 0;
1303
1304 /* Zero window and all data acked? Probe. */
1305 avail_size = mptcp_check_allowed_size(msk, data_seq, avail_size);
1306 if (avail_size == 0) {
1307 u64 snd_una = READ_ONCE(msk->snd_una);
1308
1309 if (skb || snd_una != msk->snd_nxt)
1310 return 0;
1311 zero_window_probe = true;
1312 data_seq = snd_una - 1;
1313 avail_size = 1;
1314 }
1315
1316 if (WARN_ON_ONCE(info->sent > info->limit ||
1317 info->limit > dfrag->data_len))
1318 return 0;
1319
1320 ret = info->limit - info->sent;
1321 tail = tcp_build_frag(ssk, avail_size + size_bias, info->flags,
1322 dfrag->page, dfrag->offset + info->sent, &ret);
1323 if (!tail) {
1324 tcp_remove_empty_skb(sk, tcp_write_queue_tail(ssk));
1325 return -ENOMEM;
1326 }
1327
1328 /* if the tail skb is still the cached one, collapsing really happened.
1329 */
1330 if (skb == tail) {
1331 TCP_SKB_CB(tail)->tcp_flags &= ~TCPHDR_PSH;
1332 mpext->data_len += ret;
1333 WARN_ON_ONCE(zero_window_probe);
1334 goto out;
1335 }
1336
1337 mpext = skb_ext_find(tail, SKB_EXT_MPTCP);
1338 if (WARN_ON_ONCE(!mpext)) {
1339 /* should never reach here, stream corrupted */
1340 return -EINVAL;
1341 }
1342
1343 memset(mpext, 0, sizeof(*mpext));
1344 mpext->data_seq = data_seq;
1345 mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq;
1346 mpext->data_len = ret;
1347 mpext->use_map = 1;
1348 mpext->dsn64 = 1;
1349
1350 pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d",
1351 mpext->data_seq, mpext->subflow_seq, mpext->data_len,
1352 mpext->dsn64);
1353
1354 if (zero_window_probe) {
1355 mptcp_subflow_ctx(ssk)->rel_write_seq += ret;
1356 mpext->frozen = 1;
1357 if (READ_ONCE(msk->csum_enabled))
1358 mptcp_update_data_checksum(tail, ret);
1359 tcp_push_pending_frames(ssk);
1360 return 0;
1361 }
1362out:
1363 if (READ_ONCE(msk->csum_enabled))
1364 mptcp_update_data_checksum(tail, ret);
1365 mptcp_subflow_ctx(ssk)->rel_write_seq += ret;
1366 return ret;
1367}
1368
1369#define MPTCP_SEND_BURST_SIZE ((1 << 16) - \
1370 sizeof(struct tcphdr) - \
1371 MAX_TCP_OPTION_SPACE - \
1372 sizeof(struct ipv6hdr) - \
1373 sizeof(struct frag_hdr))
1374
1375struct subflow_send_info {
1376 struct sock *ssk;
1377 u64 ratio;
1378};
1379
1380static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk)
1381{
1382 struct subflow_send_info send_info[2];
1383 struct mptcp_subflow_context *subflow;
1384 int i, nr_active = 0;
1385 struct sock *ssk;
1386 u64 ratio;
1387 u32 pace;
1388
1389 sock_owned_by_me((struct sock *)msk);
1390
1391 if (__mptcp_check_fallback(msk)) {
1392 if (!msk->first)
1393 return NULL;
1394 return sk_stream_memory_free(msk->first) ? msk->first : NULL;
1395 }
1396
1397 /* re-use last subflow, if the burst allow that */
1398 if (msk->last_snd && msk->snd_burst > 0 &&
1399 sk_stream_memory_free(msk->last_snd) &&
1400 mptcp_subflow_active(mptcp_subflow_ctx(msk->last_snd)))
1401 return msk->last_snd;
1402
1403 /* pick the subflow with the lower wmem/wspace ratio */
1404 for (i = 0; i < 2; ++i) {
1405 send_info[i].ssk = NULL;
1406 send_info[i].ratio = -1;
1407 }
1408 mptcp_for_each_subflow(msk, subflow) {
1409 trace_mptcp_subflow_get_send(subflow);
1410 ssk = mptcp_subflow_tcp_sock(subflow);
1411 if (!mptcp_subflow_active(subflow))
1412 continue;
1413
1414 nr_active += !subflow->backup;
1415 if (!sk_stream_memory_free(subflow->tcp_sock) || !tcp_sk(ssk)->snd_wnd)
1416 continue;
1417
1418 pace = READ_ONCE(ssk->sk_pacing_rate);
1419 if (!pace)
1420 continue;
1421
1422 ratio = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32,
1423 pace);
1424 if (ratio < send_info[subflow->backup].ratio) {
1425 send_info[subflow->backup].ssk = ssk;
1426 send_info[subflow->backup].ratio = ratio;
1427 }
1428 }
1429
1430 /* pick the best backup if no other subflow is active */
1431 if (!nr_active)
1432 send_info[0].ssk = send_info[1].ssk;
1433
1434 if (send_info[0].ssk) {
1435 msk->last_snd = send_info[0].ssk;
1436 msk->snd_burst = min_t(int, MPTCP_SEND_BURST_SIZE,
1437 tcp_sk(msk->last_snd)->snd_wnd);
1438 return msk->last_snd;
1439 }
1440
1441 return NULL;
1442}
1443
1444static void mptcp_push_release(struct sock *sk, struct sock *ssk,
1445 struct mptcp_sendmsg_info *info)
1446{
1447 mptcp_set_timeout(sk, ssk);
1448 tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal);
1449 release_sock(ssk);
1450}
1451
1452static void __mptcp_push_pending(struct sock *sk, unsigned int flags)
1453{
1454 struct sock *prev_ssk = NULL, *ssk = NULL;
1455 struct mptcp_sock *msk = mptcp_sk(sk);
1456 struct mptcp_sendmsg_info info = {
1457 .flags = flags,
1458 };
1459 struct mptcp_data_frag *dfrag;
1460 int len, copied = 0;
1461
1462 while ((dfrag = mptcp_send_head(sk))) {
1463 info.sent = dfrag->already_sent;
1464 info.limit = dfrag->data_len;
1465 len = dfrag->data_len - dfrag->already_sent;
1466 while (len > 0) {
1467 int ret = 0;
1468
1469 prev_ssk = ssk;
1470 mptcp_flush_join_list(msk);
1471 ssk = mptcp_subflow_get_send(msk);
1472
1473 /* try to keep the subflow socket lock across
1474 * consecutive xmit on the same socket
1475 */
1476 if (ssk != prev_ssk && prev_ssk)
1477 mptcp_push_release(sk, prev_ssk, &info);
1478 if (!ssk)
1479 goto out;
1480
1481 if (ssk != prev_ssk || !prev_ssk)
1482 lock_sock(ssk);
1483
1484 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
1485 if (ret <= 0) {
1486 mptcp_push_release(sk, ssk, &info);
1487 goto out;
1488 }
1489
1490 info.sent += ret;
1491 dfrag->already_sent += ret;
1492 msk->snd_nxt += ret;
1493 msk->snd_burst -= ret;
1494 msk->tx_pending_data -= ret;
1495 copied += ret;
1496 len -= ret;
1497 }
1498 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1499 }
1500
1501 /* at this point we held the socket lock for the last subflow we used */
1502 if (ssk)
1503 mptcp_push_release(sk, ssk, &info);
1504
1505out:
1506 if (copied) {
1507 /* start the timer, if it's not pending */
1508 if (!mptcp_timer_pending(sk))
1509 mptcp_reset_timer(sk);
1510 __mptcp_check_send_data_fin(sk);
1511 }
1512}
1513
1514static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk)
1515{
1516 struct mptcp_sock *msk = mptcp_sk(sk);
1517 struct mptcp_sendmsg_info info = {
1518 .data_lock_held = true,
1519 };
1520 struct mptcp_data_frag *dfrag;
1521 struct sock *xmit_ssk;
1522 int len, copied = 0;
1523 bool first = true;
1524
1525 info.flags = 0;
1526 while ((dfrag = mptcp_send_head(sk))) {
1527 info.sent = dfrag->already_sent;
1528 info.limit = dfrag->data_len;
1529 len = dfrag->data_len - dfrag->already_sent;
1530 while (len > 0) {
1531 int ret = 0;
1532
1533 /* the caller already invoked the packet scheduler,
1534 * check for a different subflow usage only after
1535 * spooling the first chunk of data
1536 */
1537 xmit_ssk = first ? ssk : mptcp_subflow_get_send(mptcp_sk(sk));
1538 if (!xmit_ssk)
1539 goto out;
1540 if (xmit_ssk != ssk) {
1541 mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk));
1542 goto out;
1543 }
1544
1545 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
1546 if (ret <= 0)
1547 goto out;
1548
1549 info.sent += ret;
1550 dfrag->already_sent += ret;
1551 msk->snd_nxt += ret;
1552 msk->snd_burst -= ret;
1553 msk->tx_pending_data -= ret;
1554 copied += ret;
1555 len -= ret;
1556 first = false;
1557 }
1558 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1559 }
1560
1561out:
1562 /* __mptcp_alloc_tx_skb could have released some wmem and we are
1563 * not going to flush it via release_sock()
1564 */
1565 __mptcp_update_wmem(sk);
1566 if (copied) {
1567 mptcp_set_timeout(sk, ssk);
1568 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
1569 info.size_goal);
1570 if (!mptcp_timer_pending(sk))
1571 mptcp_reset_timer(sk);
1572
1573 if (msk->snd_data_fin_enable &&
1574 msk->snd_nxt + 1 == msk->write_seq)
1575 mptcp_schedule_work(sk);
1576 }
1577}
1578
1579static void mptcp_set_nospace(struct sock *sk)
1580{
1581 /* enable autotune */
1582 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1583
1584 /* will be cleared on avail space */
1585 set_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags);
1586}
1587
1588static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
1589{
1590 struct mptcp_sock *msk = mptcp_sk(sk);
1591 struct page_frag *pfrag;
1592 size_t copied = 0;
1593 int ret = 0;
1594 long timeo;
1595
1596 /* we don't support FASTOPEN yet */
1597 if (msg->msg_flags & MSG_FASTOPEN)
1598 return -EOPNOTSUPP;
1599
1600 /* silently ignore everything else */
1601 msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL;
1602
1603 mptcp_lock_sock(sk, __mptcp_wmem_reserve(sk, min_t(size_t, 1 << 20, len)));
1604
1605 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1606
1607 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
1608 ret = sk_stream_wait_connect(sk, &timeo);
1609 if (ret)
1610 goto out;
1611 }
1612
1613 pfrag = sk_page_frag(sk);
1614
1615 while (msg_data_left(msg)) {
1616 int total_ts, frag_truesize = 0;
1617 struct mptcp_data_frag *dfrag;
1618 bool dfrag_collapsed;
1619 size_t psize, offset;
1620
1621 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) {
1622 ret = -EPIPE;
1623 goto out;
1624 }
1625
1626 /* reuse tail pfrag, if possible, or carve a new one from the
1627 * page allocator
1628 */
1629 dfrag = mptcp_pending_tail(sk);
1630 dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag);
1631 if (!dfrag_collapsed) {
1632 if (!sk_stream_memory_free(sk))
1633 goto wait_for_memory;
1634
1635 if (!mptcp_page_frag_refill(sk, pfrag))
1636 goto wait_for_memory;
1637
1638 dfrag = mptcp_carve_data_frag(msk, pfrag, pfrag->offset);
1639 frag_truesize = dfrag->overhead;
1640 }
1641
1642 /* we do not bound vs wspace, to allow a single packet.
1643 * memory accounting will prevent execessive memory usage
1644 * anyway
1645 */
1646 offset = dfrag->offset + dfrag->data_len;
1647 psize = pfrag->size - offset;
1648 psize = min_t(size_t, psize, msg_data_left(msg));
1649 total_ts = psize + frag_truesize;
1650
1651 if (!mptcp_wmem_alloc(sk, total_ts))
1652 goto wait_for_memory;
1653
1654 if (copy_page_from_iter(dfrag->page, offset, psize,
1655 &msg->msg_iter) != psize) {
1656 mptcp_wmem_uncharge(sk, psize + frag_truesize);
1657 ret = -EFAULT;
1658 goto out;
1659 }
1660
1661 /* data successfully copied into the write queue */
1662 copied += psize;
1663 dfrag->data_len += psize;
1664 frag_truesize += psize;
1665 pfrag->offset += frag_truesize;
1666 WRITE_ONCE(msk->write_seq, msk->write_seq + psize);
1667 msk->tx_pending_data += psize;
1668
1669 /* charge data on mptcp pending queue to the msk socket
1670 * Note: we charge such data both to sk and ssk
1671 */
1672 sk_wmem_queued_add(sk, frag_truesize);
1673 if (!dfrag_collapsed) {
1674 get_page(dfrag->page);
1675 list_add_tail(&dfrag->list, &msk->rtx_queue);
1676 if (!msk->first_pending)
1677 WRITE_ONCE(msk->first_pending, dfrag);
1678 }
1679 pr_debug("msk=%p dfrag at seq=%llu len=%u sent=%u new=%d", msk,
1680 dfrag->data_seq, dfrag->data_len, dfrag->already_sent,
1681 !dfrag_collapsed);
1682
1683 continue;
1684
1685wait_for_memory:
1686 mptcp_set_nospace(sk);
1687 __mptcp_push_pending(sk, msg->msg_flags);
1688 ret = sk_stream_wait_memory(sk, &timeo);
1689 if (ret)
1690 goto out;
1691 }
1692
1693 if (copied)
1694 __mptcp_push_pending(sk, msg->msg_flags);
1695
1696out:
1697 release_sock(sk);
1698 return copied ? : ret;
1699}
1700
1701static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk,
1702 struct msghdr *msg,
1703 size_t len, int flags,
1704 struct scm_timestamping_internal *tss,
1705 int *cmsg_flags)
1706{
1707 struct sk_buff *skb, *tmp;
1708 int copied = 0;
1709
1710 skb_queue_walk_safe(&msk->receive_queue, skb, tmp) {
1711 u32 offset = MPTCP_SKB_CB(skb)->offset;
1712 u32 data_len = skb->len - offset;
1713 u32 count = min_t(size_t, len - copied, data_len);
1714 int err;
1715
1716 if (!(flags & MSG_TRUNC)) {
1717 err = skb_copy_datagram_msg(skb, offset, msg, count);
1718 if (unlikely(err < 0)) {
1719 if (!copied)
1720 return err;
1721 break;
1722 }
1723 }
1724
1725 if (MPTCP_SKB_CB(skb)->has_rxtstamp) {
1726 tcp_update_recv_tstamps(skb, tss);
1727 *cmsg_flags |= MPTCP_CMSG_TS;
1728 }
1729
1730 copied += count;
1731
1732 if (count < data_len) {
1733 if (!(flags & MSG_PEEK))
1734 MPTCP_SKB_CB(skb)->offset += count;
1735 break;
1736 }
1737
1738 if (!(flags & MSG_PEEK)) {
1739 /* we will bulk release the skb memory later */
1740 skb->destructor = NULL;
1741 WRITE_ONCE(msk->rmem_released, msk->rmem_released + skb->truesize);
1742 __skb_unlink(skb, &msk->receive_queue);
1743 __kfree_skb(skb);
1744 }
1745
1746 if (copied >= len)
1747 break;
1748 }
1749
1750 return copied;
1751}
1752
1753/* receive buffer autotuning. See tcp_rcv_space_adjust for more information.
1754 *
1755 * Only difference: Use highest rtt estimate of the subflows in use.
1756 */
1757static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied)
1758{
1759 struct mptcp_subflow_context *subflow;
1760 struct sock *sk = (struct sock *)msk;
1761 u32 time, advmss = 1;
1762 u64 rtt_us, mstamp;
1763
1764 sock_owned_by_me(sk);
1765
1766 if (copied <= 0)
1767 return;
1768
1769 msk->rcvq_space.copied += copied;
1770
1771 mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC);
1772 time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time);
1773
1774 rtt_us = msk->rcvq_space.rtt_us;
1775 if (rtt_us && time < (rtt_us >> 3))
1776 return;
1777
1778 rtt_us = 0;
1779 mptcp_for_each_subflow(msk, subflow) {
1780 const struct tcp_sock *tp;
1781 u64 sf_rtt_us;
1782 u32 sf_advmss;
1783
1784 tp = tcp_sk(mptcp_subflow_tcp_sock(subflow));
1785
1786 sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us);
1787 sf_advmss = READ_ONCE(tp->advmss);
1788
1789 rtt_us = max(sf_rtt_us, rtt_us);
1790 advmss = max(sf_advmss, advmss);
1791 }
1792
1793 msk->rcvq_space.rtt_us = rtt_us;
1794 if (time < (rtt_us >> 3) || rtt_us == 0)
1795 return;
1796
1797 if (msk->rcvq_space.copied <= msk->rcvq_space.space)
1798 goto new_measure;
1799
1800 if (sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf &&
1801 !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
1802 int rcvmem, rcvbuf;
1803 u64 rcvwin, grow;
1804
1805 rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss;
1806
1807 grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space);
1808
1809 do_div(grow, msk->rcvq_space.space);
1810 rcvwin += (grow << 1);
1811
1812 rcvmem = SKB_TRUESIZE(advmss + MAX_TCP_HEADER);
1813 while (tcp_win_from_space(sk, rcvmem) < advmss)
1814 rcvmem += 128;
1815
1816 do_div(rcvwin, advmss);
1817 rcvbuf = min_t(u64, rcvwin * rcvmem,
1818 sock_net(sk)->ipv4.sysctl_tcp_rmem[2]);
1819
1820 if (rcvbuf > sk->sk_rcvbuf) {
1821 u32 window_clamp;
1822
1823 window_clamp = tcp_win_from_space(sk, rcvbuf);
1824 WRITE_ONCE(sk->sk_rcvbuf, rcvbuf);
1825
1826 /* Make subflows follow along. If we do not do this, we
1827 * get drops at subflow level if skbs can't be moved to
1828 * the mptcp rx queue fast enough (announced rcv_win can
1829 * exceed ssk->sk_rcvbuf).
1830 */
1831 mptcp_for_each_subflow(msk, subflow) {
1832 struct sock *ssk;
1833 bool slow;
1834
1835 ssk = mptcp_subflow_tcp_sock(subflow);
1836 slow = lock_sock_fast(ssk);
1837 WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf);
1838 tcp_sk(ssk)->window_clamp = window_clamp;
1839 tcp_cleanup_rbuf(ssk, 1);
1840 unlock_sock_fast(ssk, slow);
1841 }
1842 }
1843 }
1844
1845 msk->rcvq_space.space = msk->rcvq_space.copied;
1846new_measure:
1847 msk->rcvq_space.copied = 0;
1848 msk->rcvq_space.time = mstamp;
1849}
1850
1851static void __mptcp_update_rmem(struct sock *sk)
1852{
1853 struct mptcp_sock *msk = mptcp_sk(sk);
1854
1855 if (!msk->rmem_released)
1856 return;
1857
1858 atomic_sub(msk->rmem_released, &sk->sk_rmem_alloc);
1859 sk_mem_uncharge(sk, msk->rmem_released);
1860 WRITE_ONCE(msk->rmem_released, 0);
1861}
1862
1863static void __mptcp_splice_receive_queue(struct sock *sk)
1864{
1865 struct mptcp_sock *msk = mptcp_sk(sk);
1866
1867 skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue);
1868}
1869
1870static bool __mptcp_move_skbs(struct mptcp_sock *msk)
1871{
1872 struct sock *sk = (struct sock *)msk;
1873 unsigned int moved = 0;
1874 bool ret, done;
1875
1876 mptcp_flush_join_list(msk);
1877 do {
1878 struct sock *ssk = mptcp_subflow_recv_lookup(msk);
1879 bool slowpath;
1880
1881 /* we can have data pending in the subflows only if the msk
1882 * receive buffer was full at subflow_data_ready() time,
1883 * that is an unlikely slow path.
1884 */
1885 if (likely(!ssk))
1886 break;
1887
1888 slowpath = lock_sock_fast(ssk);
1889 mptcp_data_lock(sk);
1890 __mptcp_update_rmem(sk);
1891 done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
1892 mptcp_data_unlock(sk);
1893
1894 if (unlikely(ssk->sk_err))
1895 __mptcp_error_report(sk);
1896 unlock_sock_fast(ssk, slowpath);
1897 } while (!done);
1898
1899 /* acquire the data lock only if some input data is pending */
1900 ret = moved > 0;
1901 if (!RB_EMPTY_ROOT(&msk->out_of_order_queue) ||
1902 !skb_queue_empty_lockless(&sk->sk_receive_queue)) {
1903 mptcp_data_lock(sk);
1904 __mptcp_update_rmem(sk);
1905 ret |= __mptcp_ofo_queue(msk);
1906 __mptcp_splice_receive_queue(sk);
1907 mptcp_data_unlock(sk);
1908 }
1909 if (ret)
1910 mptcp_check_data_fin((struct sock *)msk);
1911 return !skb_queue_empty(&msk->receive_queue);
1912}
1913
1914static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
1915 int nonblock, int flags, int *addr_len)
1916{
1917 struct mptcp_sock *msk = mptcp_sk(sk);
1918 struct scm_timestamping_internal tss;
1919 int copied = 0, cmsg_flags = 0;
1920 int target;
1921 long timeo;
1922
1923 /* MSG_ERRQUEUE is really a no-op till we support IP_RECVERR */
1924 if (unlikely(flags & MSG_ERRQUEUE))
1925 return inet_recv_error(sk, msg, len, addr_len);
1926
1927 mptcp_lock_sock(sk, __mptcp_splice_receive_queue(sk));
1928 if (unlikely(sk->sk_state == TCP_LISTEN)) {
1929 copied = -ENOTCONN;
1930 goto out_err;
1931 }
1932
1933 timeo = sock_rcvtimeo(sk, nonblock);
1934
1935 len = min_t(size_t, len, INT_MAX);
1936 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1937
1938 while (copied < len) {
1939 int bytes_read;
1940
1941 bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags, &tss, &cmsg_flags);
1942 if (unlikely(bytes_read < 0)) {
1943 if (!copied)
1944 copied = bytes_read;
1945 goto out_err;
1946 }
1947
1948 copied += bytes_read;
1949
1950 /* be sure to advertise window change */
1951 mptcp_cleanup_rbuf(msk);
1952
1953 if (skb_queue_empty(&msk->receive_queue) && __mptcp_move_skbs(msk))
1954 continue;
1955
1956 /* only the master socket status is relevant here. The exit
1957 * conditions mirror closely tcp_recvmsg()
1958 */
1959 if (copied >= target)
1960 break;
1961
1962 if (copied) {
1963 if (sk->sk_err ||
1964 sk->sk_state == TCP_CLOSE ||
1965 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1966 !timeo ||
1967 signal_pending(current))
1968 break;
1969 } else {
1970 if (sk->sk_err) {
1971 copied = sock_error(sk);
1972 break;
1973 }
1974
1975 if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
1976 mptcp_check_for_eof(msk);
1977
1978 if (sk->sk_shutdown & RCV_SHUTDOWN) {
1979 /* race breaker: the shutdown could be after the
1980 * previous receive queue check
1981 */
1982 if (__mptcp_move_skbs(msk))
1983 continue;
1984 break;
1985 }
1986
1987 if (sk->sk_state == TCP_CLOSE) {
1988 copied = -ENOTCONN;
1989 break;
1990 }
1991
1992 if (!timeo) {
1993 copied = -EAGAIN;
1994 break;
1995 }
1996
1997 if (signal_pending(current)) {
1998 copied = sock_intr_errno(timeo);
1999 break;
2000 }
2001 }
2002
2003 pr_debug("block timeout %ld", timeo);
2004 sk_wait_data(sk, &timeo, NULL);
2005 }
2006
2007out_err:
2008 if (cmsg_flags && copied >= 0) {
2009 if (cmsg_flags & MPTCP_CMSG_TS)
2010 tcp_recv_timestamp(msg, sk, &tss);
2011 }
2012
2013 pr_debug("msk=%p rx queue empty=%d:%d copied=%d",
2014 msk, skb_queue_empty_lockless(&sk->sk_receive_queue),
2015 skb_queue_empty(&msk->receive_queue), copied);
2016 if (!(flags & MSG_PEEK))
2017 mptcp_rcv_space_adjust(msk, copied);
2018
2019 release_sock(sk);
2020 return copied;
2021}
2022
2023static void mptcp_retransmit_timer(struct timer_list *t)
2024{
2025 struct inet_connection_sock *icsk = from_timer(icsk, t,
2026 icsk_retransmit_timer);
2027 struct sock *sk = &icsk->icsk_inet.sk;
2028 struct mptcp_sock *msk = mptcp_sk(sk);
2029
2030 bh_lock_sock(sk);
2031 if (!sock_owned_by_user(sk)) {
2032 /* we need a process context to retransmit */
2033 if (!test_and_set_bit(MPTCP_WORK_RTX, &msk->flags))
2034 mptcp_schedule_work(sk);
2035 } else {
2036 /* delegate our work to tcp_release_cb() */
2037 set_bit(MPTCP_RETRANSMIT, &msk->flags);
2038 }
2039 bh_unlock_sock(sk);
2040 sock_put(sk);
2041}
2042
2043static void mptcp_timeout_timer(struct timer_list *t)
2044{
2045 struct sock *sk = from_timer(sk, t, sk_timer);
2046
2047 mptcp_schedule_work(sk);
2048 sock_put(sk);
2049}
2050
2051/* Find an idle subflow. Return NULL if there is unacked data at tcp
2052 * level.
2053 *
2054 * A backup subflow is returned only if that is the only kind available.
2055 */
2056static struct sock *mptcp_subflow_get_retrans(const struct mptcp_sock *msk)
2057{
2058 struct mptcp_subflow_context *subflow;
2059 struct sock *backup = NULL;
2060
2061 sock_owned_by_me((const struct sock *)msk);
2062
2063 if (__mptcp_check_fallback(msk))
2064 return NULL;
2065
2066 mptcp_for_each_subflow(msk, subflow) {
2067 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2068
2069 if (!mptcp_subflow_active(subflow))
2070 continue;
2071
2072 /* still data outstanding at TCP level? Don't retransmit. */
2073 if (!tcp_write_queue_empty(ssk)) {
2074 if (inet_csk(ssk)->icsk_ca_state >= TCP_CA_Loss)
2075 continue;
2076 return NULL;
2077 }
2078
2079 if (subflow->backup) {
2080 if (!backup)
2081 backup = ssk;
2082 continue;
2083 }
2084
2085 return ssk;
2086 }
2087
2088 return backup;
2089}
2090
2091static void mptcp_dispose_initial_subflow(struct mptcp_sock *msk)
2092{
2093 if (msk->subflow) {
2094 iput(SOCK_INODE(msk->subflow));
2095 msk->subflow = NULL;
2096 }
2097}
2098
2099/* subflow sockets can be either outgoing (connect) or incoming
2100 * (accept).
2101 *
2102 * Outgoing subflows use in-kernel sockets.
2103 * Incoming subflows do not have their own 'struct socket' allocated,
2104 * so we need to use tcp_close() after detaching them from the mptcp
2105 * parent socket.
2106 */
2107static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
2108 struct mptcp_subflow_context *subflow)
2109{
2110 struct mptcp_sock *msk = mptcp_sk(sk);
2111
2112 list_del(&subflow->node);
2113
2114 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
2115
2116 /* if we are invoked by the msk cleanup code, the subflow is
2117 * already orphaned
2118 */
2119 if (ssk->sk_socket)
2120 sock_orphan(ssk);
2121
2122 subflow->disposable = 1;
2123
2124 /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops
2125 * the ssk has been already destroyed, we just need to release the
2126 * reference owned by msk;
2127 */
2128 if (!inet_csk(ssk)->icsk_ulp_ops) {
2129 kfree_rcu(subflow, rcu);
2130 } else {
2131 /* otherwise tcp will dispose of the ssk and subflow ctx */
2132 __tcp_close(ssk, 0);
2133
2134 /* close acquired an extra ref */
2135 __sock_put(ssk);
2136 }
2137 release_sock(ssk);
2138
2139 sock_put(ssk);
2140
2141 if (ssk == msk->last_snd)
2142 msk->last_snd = NULL;
2143
2144 if (ssk == msk->first)
2145 msk->first = NULL;
2146
2147 if (msk->subflow && ssk == msk->subflow->sk)
2148 mptcp_dispose_initial_subflow(msk);
2149}
2150
2151void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
2152 struct mptcp_subflow_context *subflow)
2153{
2154 if (sk->sk_state == TCP_ESTABLISHED)
2155 mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL);
2156 __mptcp_close_ssk(sk, ssk, subflow);
2157}
2158
2159static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu)
2160{
2161 return 0;
2162}
2163
2164static void __mptcp_close_subflow(struct mptcp_sock *msk)
2165{
2166 struct mptcp_subflow_context *subflow, *tmp;
2167
2168 might_sleep();
2169
2170 list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
2171 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2172
2173 if (inet_sk_state_load(ssk) != TCP_CLOSE)
2174 continue;
2175
2176 /* 'subflow_data_ready' will re-sched once rx queue is empty */
2177 if (!skb_queue_empty_lockless(&ssk->sk_receive_queue))
2178 continue;
2179
2180 mptcp_close_ssk((struct sock *)msk, ssk, subflow);
2181 }
2182}
2183
2184static bool mptcp_check_close_timeout(const struct sock *sk)
2185{
2186 s32 delta = tcp_jiffies32 - inet_csk(sk)->icsk_mtup.probe_timestamp;
2187 struct mptcp_subflow_context *subflow;
2188
2189 if (delta >= TCP_TIMEWAIT_LEN)
2190 return true;
2191
2192 /* if all subflows are in closed status don't bother with additional
2193 * timeout
2194 */
2195 mptcp_for_each_subflow(mptcp_sk(sk), subflow) {
2196 if (inet_sk_state_load(mptcp_subflow_tcp_sock(subflow)) !=
2197 TCP_CLOSE)
2198 return false;
2199 }
2200 return true;
2201}
2202
2203static void mptcp_check_fastclose(struct mptcp_sock *msk)
2204{
2205 struct mptcp_subflow_context *subflow, *tmp;
2206 struct sock *sk = &msk->sk.icsk_inet.sk;
2207
2208 if (likely(!READ_ONCE(msk->rcv_fastclose)))
2209 return;
2210
2211 mptcp_token_destroy(msk);
2212
2213 list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
2214 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
2215 bool slow;
2216
2217 slow = lock_sock_fast(tcp_sk);
2218 if (tcp_sk->sk_state != TCP_CLOSE) {
2219 tcp_send_active_reset(tcp_sk, GFP_ATOMIC);
2220 tcp_set_state(tcp_sk, TCP_CLOSE);
2221 }
2222 unlock_sock_fast(tcp_sk, slow);
2223 }
2224
2225 inet_sk_state_store(sk, TCP_CLOSE);
2226 sk->sk_shutdown = SHUTDOWN_MASK;
2227 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
2228 set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags);
2229
2230 mptcp_close_wake_up(sk);
2231}
2232
2233static void __mptcp_retrans(struct sock *sk)
2234{
2235 struct mptcp_sock *msk = mptcp_sk(sk);
2236 struct mptcp_sendmsg_info info = {};
2237 struct mptcp_data_frag *dfrag;
2238 size_t copied = 0;
2239 struct sock *ssk;
2240 int ret;
2241
2242 mptcp_clean_una_wakeup(sk);
2243 dfrag = mptcp_rtx_head(sk);
2244 if (!dfrag) {
2245 if (mptcp_data_fin_enabled(msk)) {
2246 struct inet_connection_sock *icsk = inet_csk(sk);
2247
2248 icsk->icsk_retransmits++;
2249 mptcp_set_datafin_timeout(sk);
2250 mptcp_send_ack(msk);
2251
2252 goto reset_timer;
2253 }
2254
2255 return;
2256 }
2257
2258 ssk = mptcp_subflow_get_retrans(msk);
2259 if (!ssk)
2260 goto reset_timer;
2261
2262 lock_sock(ssk);
2263
2264 /* limit retransmission to the bytes already sent on some subflows */
2265 info.sent = 0;
2266 info.limit = READ_ONCE(msk->csum_enabled) ? dfrag->data_len : dfrag->already_sent;
2267 while (info.sent < info.limit) {
2268 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
2269 if (ret <= 0)
2270 break;
2271
2272 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS);
2273 copied += ret;
2274 info.sent += ret;
2275 }
2276 if (copied) {
2277 dfrag->already_sent = max(dfrag->already_sent, info.sent);
2278 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
2279 info.size_goal);
2280 }
2281
2282 mptcp_set_timeout(sk, ssk);
2283 release_sock(ssk);
2284
2285reset_timer:
2286 if (!mptcp_timer_pending(sk))
2287 mptcp_reset_timer(sk);
2288}
2289
2290static void mptcp_worker(struct work_struct *work)
2291{
2292 struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
2293 struct sock *sk = &msk->sk.icsk_inet.sk;
2294 int state;
2295
2296 lock_sock(sk);
2297 state = sk->sk_state;
2298 if (unlikely(state == TCP_CLOSE))
2299 goto unlock;
2300
2301 mptcp_check_data_fin_ack(sk);
2302 mptcp_flush_join_list(msk);
2303
2304 mptcp_check_fastclose(msk);
2305
2306 if (msk->pm.status)
2307 mptcp_pm_nl_work(msk);
2308
2309 if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
2310 mptcp_check_for_eof(msk);
2311
2312 __mptcp_check_send_data_fin(sk);
2313 mptcp_check_data_fin(sk);
2314
2315 /* There is no point in keeping around an orphaned sk timedout or
2316 * closed, but we need the msk around to reply to incoming DATA_FIN,
2317 * even if it is orphaned and in FIN_WAIT2 state
2318 */
2319 if (sock_flag(sk, SOCK_DEAD) &&
2320 (mptcp_check_close_timeout(sk) || sk->sk_state == TCP_CLOSE)) {
2321 inet_sk_state_store(sk, TCP_CLOSE);
2322 __mptcp_destroy_sock(sk);
2323 goto unlock;
2324 }
2325
2326 if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
2327 __mptcp_close_subflow(msk);
2328
2329 if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
2330 __mptcp_retrans(sk);
2331
2332unlock:
2333 release_sock(sk);
2334 sock_put(sk);
2335}
2336
2337static int __mptcp_init_sock(struct sock *sk)
2338{
2339 struct mptcp_sock *msk = mptcp_sk(sk);
2340
2341 spin_lock_init(&msk->join_list_lock);
2342
2343 INIT_LIST_HEAD(&msk->conn_list);
2344 INIT_LIST_HEAD(&msk->join_list);
2345 INIT_LIST_HEAD(&msk->rtx_queue);
2346 INIT_WORK(&msk->work, mptcp_worker);
2347 __skb_queue_head_init(&msk->receive_queue);
2348 msk->out_of_order_queue = RB_ROOT;
2349 msk->first_pending = NULL;
2350 msk->wmem_reserved = 0;
2351 WRITE_ONCE(msk->rmem_released, 0);
2352 msk->tx_pending_data = 0;
2353
2354 msk->first = NULL;
2355 inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss;
2356 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
2357
2358 mptcp_pm_data_init(msk);
2359
2360 /* re-use the csk retrans timer for MPTCP-level retrans */
2361 timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0);
2362 timer_setup(&sk->sk_timer, mptcp_timeout_timer, 0);
2363
2364 return 0;
2365}
2366
2367static int mptcp_init_sock(struct sock *sk)
2368{
2369 struct inet_connection_sock *icsk = inet_csk(sk);
2370 struct net *net = sock_net(sk);
2371 int ret;
2372
2373 ret = __mptcp_init_sock(sk);
2374 if (ret)
2375 return ret;
2376
2377 if (!mptcp_is_enabled(net))
2378 return -ENOPROTOOPT;
2379
2380 if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net))
2381 return -ENOMEM;
2382
2383 ret = __mptcp_socket_create(mptcp_sk(sk));
2384 if (ret)
2385 return ret;
2386
2387 /* fetch the ca name; do it outside __mptcp_init_sock(), so that clone will
2388 * propagate the correct value
2389 */
2390 tcp_assign_congestion_control(sk);
2391 strcpy(mptcp_sk(sk)->ca_name, icsk->icsk_ca_ops->name);
2392
2393 /* no need to keep a reference to the ops, the name will suffice */
2394 tcp_cleanup_congestion_control(sk);
2395 icsk->icsk_ca_ops = NULL;
2396
2397 sk_sockets_allocated_inc(sk);
2398 sk->sk_rcvbuf = sock_net(sk)->ipv4.sysctl_tcp_rmem[1];
2399 sk->sk_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[1];
2400
2401 return 0;
2402}
2403
2404static void __mptcp_clear_xmit(struct sock *sk)
2405{
2406 struct mptcp_sock *msk = mptcp_sk(sk);
2407 struct mptcp_data_frag *dtmp, *dfrag;
2408
2409 WRITE_ONCE(msk->first_pending, NULL);
2410 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list)
2411 dfrag_clear(sk, dfrag);
2412}
2413
2414static void mptcp_cancel_work(struct sock *sk)
2415{
2416 struct mptcp_sock *msk = mptcp_sk(sk);
2417
2418 if (cancel_work_sync(&msk->work))
2419 __sock_put(sk);
2420}
2421
2422void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how)
2423{
2424 lock_sock(ssk);
2425
2426 switch (ssk->sk_state) {
2427 case TCP_LISTEN:
2428 if (!(how & RCV_SHUTDOWN))
2429 break;
2430 fallthrough;
2431 case TCP_SYN_SENT:
2432 tcp_disconnect(ssk, O_NONBLOCK);
2433 break;
2434 default:
2435 if (__mptcp_check_fallback(mptcp_sk(sk))) {
2436 pr_debug("Fallback");
2437 ssk->sk_shutdown |= how;
2438 tcp_shutdown(ssk, how);
2439 } else {
2440 pr_debug("Sending DATA_FIN on subflow %p", ssk);
2441 mptcp_set_timeout(sk, ssk);
2442 tcp_send_ack(ssk);
2443 if (!mptcp_timer_pending(sk))
2444 mptcp_reset_timer(sk);
2445 }
2446 break;
2447 }
2448
2449 release_sock(ssk);
2450}
2451
2452static const unsigned char new_state[16] = {
2453 /* current state: new state: action: */
2454 [0 /* (Invalid) */] = TCP_CLOSE,
2455 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2456 [TCP_SYN_SENT] = TCP_CLOSE,
2457 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2458 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1,
2459 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2,
2460 [TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */
2461 [TCP_CLOSE] = TCP_CLOSE,
2462 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN,
2463 [TCP_LAST_ACK] = TCP_LAST_ACK,
2464 [TCP_LISTEN] = TCP_CLOSE,
2465 [TCP_CLOSING] = TCP_CLOSING,
2466 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */
2467};
2468
2469static int mptcp_close_state(struct sock *sk)
2470{
2471 int next = (int)new_state[sk->sk_state];
2472 int ns = next & TCP_STATE_MASK;
2473
2474 inet_sk_state_store(sk, ns);
2475
2476 return next & TCP_ACTION_FIN;
2477}
2478
2479static void __mptcp_check_send_data_fin(struct sock *sk)
2480{
2481 struct mptcp_subflow_context *subflow;
2482 struct mptcp_sock *msk = mptcp_sk(sk);
2483
2484 pr_debug("msk=%p snd_data_fin_enable=%d pending=%d snd_nxt=%llu write_seq=%llu",
2485 msk, msk->snd_data_fin_enable, !!mptcp_send_head(sk),
2486 msk->snd_nxt, msk->write_seq);
2487
2488 /* we still need to enqueue subflows or not really shutting down,
2489 * skip this
2490 */
2491 if (!msk->snd_data_fin_enable || msk->snd_nxt + 1 != msk->write_seq ||
2492 mptcp_send_head(sk))
2493 return;
2494
2495 WRITE_ONCE(msk->snd_nxt, msk->write_seq);
2496
2497 /* fallback socket will not get data_fin/ack, can move to the next
2498 * state now
2499 */
2500 if (__mptcp_check_fallback(msk)) {
2501 if ((1 << sk->sk_state) & (TCPF_CLOSING | TCPF_LAST_ACK)) {
2502 inet_sk_state_store(sk, TCP_CLOSE);
2503 mptcp_close_wake_up(sk);
2504 } else if (sk->sk_state == TCP_FIN_WAIT1) {
2505 inet_sk_state_store(sk, TCP_FIN_WAIT2);
2506 }
2507 }
2508
2509 mptcp_flush_join_list(msk);
2510 mptcp_for_each_subflow(msk, subflow) {
2511 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
2512
2513 mptcp_subflow_shutdown(sk, tcp_sk, SEND_SHUTDOWN);
2514 }
2515}
2516
2517static void __mptcp_wr_shutdown(struct sock *sk)
2518{
2519 struct mptcp_sock *msk = mptcp_sk(sk);
2520
2521 pr_debug("msk=%p snd_data_fin_enable=%d shutdown=%x state=%d pending=%d",
2522 msk, msk->snd_data_fin_enable, sk->sk_shutdown, sk->sk_state,
2523 !!mptcp_send_head(sk));
2524
2525 /* will be ignored by fallback sockets */
2526 WRITE_ONCE(msk->write_seq, msk->write_seq + 1);
2527 WRITE_ONCE(msk->snd_data_fin_enable, 1);
2528
2529 __mptcp_check_send_data_fin(sk);
2530}
2531
2532static void __mptcp_destroy_sock(struct sock *sk)
2533{
2534 struct mptcp_subflow_context *subflow, *tmp;
2535 struct mptcp_sock *msk = mptcp_sk(sk);
2536 LIST_HEAD(conn_list);
2537
2538 pr_debug("msk=%p", msk);
2539
2540 might_sleep();
2541
2542 /* be sure to always acquire the join list lock, to sync vs
2543 * mptcp_finish_join().
2544 */
2545 spin_lock_bh(&msk->join_list_lock);
2546 list_splice_tail_init(&msk->join_list, &msk->conn_list);
2547 spin_unlock_bh(&msk->join_list_lock);
2548 list_splice_init(&msk->conn_list, &conn_list);
2549
2550 sk_stop_timer(sk, &msk->sk.icsk_retransmit_timer);
2551 sk_stop_timer(sk, &sk->sk_timer);
2552 msk->pm.status = 0;
2553
2554 list_for_each_entry_safe(subflow, tmp, &conn_list, node) {
2555 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2556 __mptcp_close_ssk(sk, ssk, subflow);
2557 }
2558
2559 sk->sk_prot->destroy(sk);
2560
2561 WARN_ON_ONCE(msk->wmem_reserved);
2562 WARN_ON_ONCE(msk->rmem_released);
2563 sk_stream_kill_queues(sk);
2564 xfrm_sk_free_policy(sk);
2565
2566 sk_refcnt_debug_release(sk);
2567 mptcp_dispose_initial_subflow(msk);
2568 sock_put(sk);
2569}
2570
2571static void mptcp_close(struct sock *sk, long timeout)
2572{
2573 struct mptcp_subflow_context *subflow;
2574 bool do_cancel_work = false;
2575
2576 lock_sock(sk);
2577 sk->sk_shutdown = SHUTDOWN_MASK;
2578
2579 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) {
2580 inet_sk_state_store(sk, TCP_CLOSE);
2581 goto cleanup;
2582 }
2583
2584 if (mptcp_close_state(sk))
2585 __mptcp_wr_shutdown(sk);
2586
2587 sk_stream_wait_close(sk, timeout);
2588
2589cleanup:
2590 /* orphan all the subflows */
2591 inet_csk(sk)->icsk_mtup.probe_timestamp = tcp_jiffies32;
2592 mptcp_for_each_subflow(mptcp_sk(sk), subflow) {
2593 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2594 bool slow = lock_sock_fast(ssk);
2595
2596 sock_orphan(ssk);
2597 unlock_sock_fast(ssk, slow);
2598 }
2599 sock_orphan(sk);
2600
2601 sock_hold(sk);
2602 pr_debug("msk=%p state=%d", sk, sk->sk_state);
2603 if (sk->sk_state == TCP_CLOSE) {
2604 __mptcp_destroy_sock(sk);
2605 do_cancel_work = true;
2606 } else {
2607 sk_reset_timer(sk, &sk->sk_timer, jiffies + TCP_TIMEWAIT_LEN);
2608 }
2609 release_sock(sk);
2610 if (do_cancel_work)
2611 mptcp_cancel_work(sk);
2612
2613 if (mptcp_sk(sk)->token)
2614 mptcp_event(MPTCP_EVENT_CLOSED, mptcp_sk(sk), NULL, GFP_KERNEL);
2615
2616 sock_put(sk);
2617}
2618
2619static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk)
2620{
2621#if IS_ENABLED(CONFIG_MPTCP_IPV6)
2622 const struct ipv6_pinfo *ssk6 = inet6_sk(ssk);
2623 struct ipv6_pinfo *msk6 = inet6_sk(msk);
2624
2625 msk->sk_v6_daddr = ssk->sk_v6_daddr;
2626 msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr;
2627
2628 if (msk6 && ssk6) {
2629 msk6->saddr = ssk6->saddr;
2630 msk6->flow_label = ssk6->flow_label;
2631 }
2632#endif
2633
2634 inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num;
2635 inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport;
2636 inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport;
2637 inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr;
2638 inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr;
2639 inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr;
2640}
2641
2642static int mptcp_disconnect(struct sock *sk, int flags)
2643{
2644 struct mptcp_subflow_context *subflow;
2645 struct mptcp_sock *msk = mptcp_sk(sk);
2646
2647 mptcp_do_flush_join_list(msk);
2648
2649 mptcp_for_each_subflow(msk, subflow) {
2650 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2651
2652 lock_sock(ssk);
2653 tcp_disconnect(ssk, flags);
2654 release_sock(ssk);
2655 }
2656 return 0;
2657}
2658
2659#if IS_ENABLED(CONFIG_MPTCP_IPV6)
2660static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk)
2661{
2662 unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo);
2663
2664 return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
2665}
2666#endif
2667
2668struct sock *mptcp_sk_clone(const struct sock *sk,
2669 const struct mptcp_options_received *mp_opt,
2670 struct request_sock *req)
2671{
2672 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
2673 struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC);
2674 struct mptcp_sock *msk;
2675 u64 ack_seq;
2676
2677 if (!nsk)
2678 return NULL;
2679
2680#if IS_ENABLED(CONFIG_MPTCP_IPV6)
2681 if (nsk->sk_family == AF_INET6)
2682 inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk);
2683#endif
2684
2685 __mptcp_init_sock(nsk);
2686
2687 msk = mptcp_sk(nsk);
2688 msk->local_key = subflow_req->local_key;
2689 msk->token = subflow_req->token;
2690 msk->subflow = NULL;
2691 WRITE_ONCE(msk->fully_established, false);
2692 if (mp_opt->csum_reqd)
2693 WRITE_ONCE(msk->csum_enabled, true);
2694
2695 msk->write_seq = subflow_req->idsn + 1;
2696 msk->snd_nxt = msk->write_seq;
2697 msk->snd_una = msk->write_seq;
2698 msk->wnd_end = msk->snd_nxt + req->rsk_rcv_wnd;
2699 msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq;
2700
2701 if (mp_opt->mp_capable) {
2702 msk->can_ack = true;
2703 msk->remote_key = mp_opt->sndr_key;
2704 mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq);
2705 ack_seq++;
2706 WRITE_ONCE(msk->ack_seq, ack_seq);
2707 WRITE_ONCE(msk->rcv_wnd_sent, ack_seq);
2708 }
2709
2710 sock_reset_flag(nsk, SOCK_RCU_FREE);
2711 /* will be fully established after successful MPC subflow creation */
2712 inet_sk_state_store(nsk, TCP_SYN_RECV);
2713
2714 security_inet_csk_clone(nsk, req);
2715 bh_unlock_sock(nsk);
2716
2717 /* keep a single reference */
2718 __sock_put(nsk);
2719 return nsk;
2720}
2721
2722void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk)
2723{
2724 const struct tcp_sock *tp = tcp_sk(ssk);
2725
2726 msk->rcvq_space.copied = 0;
2727 msk->rcvq_space.rtt_us = 0;
2728
2729 msk->rcvq_space.time = tp->tcp_mstamp;
2730
2731 /* initial rcv_space offering made to peer */
2732 msk->rcvq_space.space = min_t(u32, tp->rcv_wnd,
2733 TCP_INIT_CWND * tp->advmss);
2734 if (msk->rcvq_space.space == 0)
2735 msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT;
2736
2737 WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd);
2738}
2739
2740static struct sock *mptcp_accept(struct sock *sk, int flags, int *err,
2741 bool kern)
2742{
2743 struct mptcp_sock *msk = mptcp_sk(sk);
2744 struct socket *listener;
2745 struct sock *newsk;
2746
2747 listener = __mptcp_nmpc_socket(msk);
2748 if (WARN_ON_ONCE(!listener)) {
2749 *err = -EINVAL;
2750 return NULL;
2751 }
2752
2753 pr_debug("msk=%p, listener=%p", msk, mptcp_subflow_ctx(listener->sk));
2754 newsk = inet_csk_accept(listener->sk, flags, err, kern);
2755 if (!newsk)
2756 return NULL;
2757
2758 pr_debug("msk=%p, subflow is mptcp=%d", msk, sk_is_mptcp(newsk));
2759 if (sk_is_mptcp(newsk)) {
2760 struct mptcp_subflow_context *subflow;
2761 struct sock *new_mptcp_sock;
2762
2763 subflow = mptcp_subflow_ctx(newsk);
2764 new_mptcp_sock = subflow->conn;
2765
2766 /* is_mptcp should be false if subflow->conn is missing, see
2767 * subflow_syn_recv_sock()
2768 */
2769 if (WARN_ON_ONCE(!new_mptcp_sock)) {
2770 tcp_sk(newsk)->is_mptcp = 0;
2771 return newsk;
2772 }
2773
2774 /* acquire the 2nd reference for the owning socket */
2775 sock_hold(new_mptcp_sock);
2776 newsk = new_mptcp_sock;
2777 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEPASSIVEACK);
2778 } else {
2779 MPTCP_INC_STATS(sock_net(sk),
2780 MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK);
2781 }
2782
2783 return newsk;
2784}
2785
2786void mptcp_destroy_common(struct mptcp_sock *msk)
2787{
2788 struct sock *sk = (struct sock *)msk;
2789
2790 __mptcp_clear_xmit(sk);
2791
2792 /* move to sk_receive_queue, sk_stream_kill_queues will purge it */
2793 skb_queue_splice_tail_init(&msk->receive_queue, &sk->sk_receive_queue);
2794
2795 skb_rbtree_purge(&msk->out_of_order_queue);
2796 mptcp_token_destroy(msk);
2797 mptcp_pm_free_anno_list(msk);
2798}
2799
2800static void mptcp_destroy(struct sock *sk)
2801{
2802 struct mptcp_sock *msk = mptcp_sk(sk);
2803
2804 mptcp_destroy_common(msk);
2805 sk_sockets_allocated_dec(sk);
2806}
2807
2808void __mptcp_data_acked(struct sock *sk)
2809{
2810 if (!sock_owned_by_user(sk))
2811 __mptcp_clean_una(sk);
2812 else
2813 set_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->flags);
2814
2815 if (mptcp_pending_data_fin_ack(sk))
2816 mptcp_schedule_work(sk);
2817}
2818
2819void __mptcp_check_push(struct sock *sk, struct sock *ssk)
2820{
2821 if (!mptcp_send_head(sk))
2822 return;
2823
2824 if (!sock_owned_by_user(sk)) {
2825 struct sock *xmit_ssk = mptcp_subflow_get_send(mptcp_sk(sk));
2826
2827 if (xmit_ssk == ssk)
2828 __mptcp_subflow_push_pending(sk, ssk);
2829 else if (xmit_ssk)
2830 mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk));
2831 } else {
2832 set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags);
2833 }
2834}
2835
2836/* processes deferred events and flush wmem */
2837static void mptcp_release_cb(struct sock *sk)
2838{
2839 for (;;) {
2840 unsigned long flags = 0;
2841
2842 if (test_and_clear_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags))
2843 flags |= BIT(MPTCP_PUSH_PENDING);
2844 if (test_and_clear_bit(MPTCP_RETRANSMIT, &mptcp_sk(sk)->flags))
2845 flags |= BIT(MPTCP_RETRANSMIT);
2846 if (!flags)
2847 break;
2848
2849 /* the following actions acquire the subflow socket lock
2850 *
2851 * 1) can't be invoked in atomic scope
2852 * 2) must avoid ABBA deadlock with msk socket spinlock: the RX
2853 * datapath acquires the msk socket spinlock while helding
2854 * the subflow socket lock
2855 */
2856
2857 spin_unlock_bh(&sk->sk_lock.slock);
2858 if (flags & BIT(MPTCP_PUSH_PENDING))
2859 __mptcp_push_pending(sk, 0);
2860 if (flags & BIT(MPTCP_RETRANSMIT))
2861 __mptcp_retrans(sk);
2862
2863 cond_resched();
2864 spin_lock_bh(&sk->sk_lock.slock);
2865 }
2866
2867 /* be sure to set the current sk state before tacking actions
2868 * depending on sk_state
2869 */
2870 if (test_and_clear_bit(MPTCP_CONNECTED, &mptcp_sk(sk)->flags))
2871 __mptcp_set_connected(sk);
2872 if (test_and_clear_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->flags))
2873 __mptcp_clean_una_wakeup(sk);
2874 if (test_and_clear_bit(MPTCP_ERROR_REPORT, &mptcp_sk(sk)->flags))
2875 __mptcp_error_report(sk);
2876
2877 /* push_pending may touch wmem_reserved, ensure we do the cleanup
2878 * later
2879 */
2880 __mptcp_update_wmem(sk);
2881 __mptcp_update_rmem(sk);
2882}
2883
2884void mptcp_subflow_process_delegated(struct sock *ssk)
2885{
2886 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
2887 struct sock *sk = subflow->conn;
2888
2889 mptcp_data_lock(sk);
2890 if (!sock_owned_by_user(sk))
2891 __mptcp_subflow_push_pending(sk, ssk);
2892 else
2893 set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags);
2894 mptcp_data_unlock(sk);
2895 mptcp_subflow_delegated_done(subflow);
2896}
2897
2898static int mptcp_hash(struct sock *sk)
2899{
2900 /* should never be called,
2901 * we hash the TCP subflows not the master socket
2902 */
2903 WARN_ON_ONCE(1);
2904 return 0;
2905}
2906
2907static void mptcp_unhash(struct sock *sk)
2908{
2909 /* called from sk_common_release(), but nothing to do here */
2910}
2911
2912static int mptcp_get_port(struct sock *sk, unsigned short snum)
2913{
2914 struct mptcp_sock *msk = mptcp_sk(sk);
2915 struct socket *ssock;
2916
2917 ssock = __mptcp_nmpc_socket(msk);
2918 pr_debug("msk=%p, subflow=%p", msk, ssock);
2919 if (WARN_ON_ONCE(!ssock))
2920 return -EINVAL;
2921
2922 return inet_csk_get_port(ssock->sk, snum);
2923}
2924
2925void mptcp_finish_connect(struct sock *ssk)
2926{
2927 struct mptcp_subflow_context *subflow;
2928 struct mptcp_sock *msk;
2929 struct sock *sk;
2930 u64 ack_seq;
2931
2932 subflow = mptcp_subflow_ctx(ssk);
2933 sk = subflow->conn;
2934 msk = mptcp_sk(sk);
2935
2936 pr_debug("msk=%p, token=%u", sk, subflow->token);
2937
2938 mptcp_crypto_key_sha(subflow->remote_key, NULL, &ack_seq);
2939 ack_seq++;
2940 subflow->map_seq = ack_seq;
2941 subflow->map_subflow_seq = 1;
2942
2943 /* the socket is not connected yet, no msk/subflow ops can access/race
2944 * accessing the field below
2945 */
2946 WRITE_ONCE(msk->remote_key, subflow->remote_key);
2947 WRITE_ONCE(msk->local_key, subflow->local_key);
2948 WRITE_ONCE(msk->write_seq, subflow->idsn + 1);
2949 WRITE_ONCE(msk->snd_nxt, msk->write_seq);
2950 WRITE_ONCE(msk->ack_seq, ack_seq);
2951 WRITE_ONCE(msk->rcv_wnd_sent, ack_seq);
2952 WRITE_ONCE(msk->can_ack, 1);
2953 WRITE_ONCE(msk->snd_una, msk->write_seq);
2954
2955 mptcp_pm_new_connection(msk, ssk, 0);
2956
2957 mptcp_rcv_space_init(msk, ssk);
2958}
2959
2960void mptcp_sock_graft(struct sock *sk, struct socket *parent)
2961{
2962 write_lock_bh(&sk->sk_callback_lock);
2963 rcu_assign_pointer(sk->sk_wq, &parent->wq);
2964 sk_set_socket(sk, parent);
2965 sk->sk_uid = SOCK_INODE(parent)->i_uid;
2966 write_unlock_bh(&sk->sk_callback_lock);
2967}
2968
2969bool mptcp_finish_join(struct sock *ssk)
2970{
2971 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
2972 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
2973 struct sock *parent = (void *)msk;
2974 struct socket *parent_sock;
2975 bool ret;
2976
2977 pr_debug("msk=%p, subflow=%p", msk, subflow);
2978
2979 /* mptcp socket already closing? */
2980 if (!mptcp_is_fully_established(parent)) {
2981 subflow->reset_reason = MPTCP_RST_EMPTCP;
2982 return false;
2983 }
2984
2985 if (!msk->pm.server_side)
2986 goto out;
2987
2988 if (!mptcp_pm_allow_new_subflow(msk)) {
2989 subflow->reset_reason = MPTCP_RST_EPROHIBIT;
2990 return false;
2991 }
2992
2993 /* active connections are already on conn_list, and we can't acquire
2994 * msk lock here.
2995 * use the join list lock as synchronization point and double-check
2996 * msk status to avoid racing with __mptcp_destroy_sock()
2997 */
2998 spin_lock_bh(&msk->join_list_lock);
2999 ret = inet_sk_state_load(parent) == TCP_ESTABLISHED;
3000 if (ret && !WARN_ON_ONCE(!list_empty(&subflow->node))) {
3001 list_add_tail(&subflow->node, &msk->join_list);
3002 sock_hold(ssk);
3003 }
3004 spin_unlock_bh(&msk->join_list_lock);
3005 if (!ret) {
3006 subflow->reset_reason = MPTCP_RST_EPROHIBIT;
3007 return false;
3008 }
3009
3010 /* attach to msk socket only after we are sure he will deal with us
3011 * at close time
3012 */
3013 parent_sock = READ_ONCE(parent->sk_socket);
3014 if (parent_sock && !ssk->sk_socket)
3015 mptcp_sock_graft(ssk, parent_sock);
3016 subflow->map_seq = READ_ONCE(msk->ack_seq);
3017out:
3018 mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC);
3019 return true;
3020}
3021
3022static void mptcp_shutdown(struct sock *sk, int how)
3023{
3024 pr_debug("sk=%p, how=%d", sk, how);
3025
3026 if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk))
3027 __mptcp_wr_shutdown(sk);
3028}
3029
3030static struct proto mptcp_prot = {
3031 .name = "MPTCP",
3032 .owner = THIS_MODULE,
3033 .init = mptcp_init_sock,
3034 .disconnect = mptcp_disconnect,
3035 .close = mptcp_close,
3036 .accept = mptcp_accept,
3037 .setsockopt = mptcp_setsockopt,
3038 .getsockopt = mptcp_getsockopt,
3039 .shutdown = mptcp_shutdown,
3040 .destroy = mptcp_destroy,
3041 .sendmsg = mptcp_sendmsg,
3042 .recvmsg = mptcp_recvmsg,
3043 .release_cb = mptcp_release_cb,
3044 .hash = mptcp_hash,
3045 .unhash = mptcp_unhash,
3046 .get_port = mptcp_get_port,
3047 .sockets_allocated = &mptcp_sockets_allocated,
3048 .memory_allocated = &tcp_memory_allocated,
3049 .memory_pressure = &tcp_memory_pressure,
3050 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
3051 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
3052 .sysctl_mem = sysctl_tcp_mem,
3053 .obj_size = sizeof(struct mptcp_sock),
3054 .slab_flags = SLAB_TYPESAFE_BY_RCU,
3055 .no_autobind = true,
3056};
3057
3058static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
3059{
3060 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3061 struct socket *ssock;
3062 int err;
3063
3064 lock_sock(sock->sk);
3065 ssock = __mptcp_nmpc_socket(msk);
3066 if (!ssock) {
3067 err = -EINVAL;
3068 goto unlock;
3069 }
3070
3071 err = ssock->ops->bind(ssock, uaddr, addr_len);
3072 if (!err)
3073 mptcp_copy_inaddrs(sock->sk, ssock->sk);
3074
3075unlock:
3076 release_sock(sock->sk);
3077 return err;
3078}
3079
3080static void mptcp_subflow_early_fallback(struct mptcp_sock *msk,
3081 struct mptcp_subflow_context *subflow)
3082{
3083 subflow->request_mptcp = 0;
3084 __mptcp_do_fallback(msk);
3085}
3086
3087static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
3088 int addr_len, int flags)
3089{
3090 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3091 struct mptcp_subflow_context *subflow;
3092 struct socket *ssock;
3093 int err;
3094
3095 lock_sock(sock->sk);
3096 if (sock->state != SS_UNCONNECTED && msk->subflow) {
3097 /* pending connection or invalid state, let existing subflow
3098 * cope with that
3099 */
3100 ssock = msk->subflow;
3101 goto do_connect;
3102 }
3103
3104 ssock = __mptcp_nmpc_socket(msk);
3105 if (!ssock) {
3106 err = -EINVAL;
3107 goto unlock;
3108 }
3109
3110 mptcp_token_destroy(msk);
3111 inet_sk_state_store(sock->sk, TCP_SYN_SENT);
3112 subflow = mptcp_subflow_ctx(ssock->sk);
3113#ifdef CONFIG_TCP_MD5SIG
3114 /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
3115 * TCP option space.
3116 */
3117 if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info))
3118 mptcp_subflow_early_fallback(msk, subflow);
3119#endif
3120 if (subflow->request_mptcp && mptcp_token_new_connect(ssock->sk)) {
3121 MPTCP_INC_STATS(sock_net(ssock->sk), MPTCP_MIB_TOKENFALLBACKINIT);
3122 mptcp_subflow_early_fallback(msk, subflow);
3123 }
3124 if (likely(!__mptcp_check_fallback(msk)))
3125 MPTCP_INC_STATS(sock_net(sock->sk), MPTCP_MIB_MPCAPABLEACTIVE);
3126
3127do_connect:
3128 err = ssock->ops->connect(ssock, uaddr, addr_len, flags);
3129 sock->state = ssock->state;
3130
3131 /* on successful connect, the msk state will be moved to established by
3132 * subflow_finish_connect()
3133 */
3134 if (!err || err == -EINPROGRESS)
3135 mptcp_copy_inaddrs(sock->sk, ssock->sk);
3136 else
3137 inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
3138
3139unlock:
3140 release_sock(sock->sk);
3141 return err;
3142}
3143
3144static int mptcp_listen(struct socket *sock, int backlog)
3145{
3146 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3147 struct socket *ssock;
3148 int err;
3149
3150 pr_debug("msk=%p", msk);
3151
3152 lock_sock(sock->sk);
3153 ssock = __mptcp_nmpc_socket(msk);
3154 if (!ssock) {
3155 err = -EINVAL;
3156 goto unlock;
3157 }
3158
3159 mptcp_token_destroy(msk);
3160 inet_sk_state_store(sock->sk, TCP_LISTEN);
3161 sock_set_flag(sock->sk, SOCK_RCU_FREE);
3162
3163 err = ssock->ops->listen(ssock, backlog);
3164 inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
3165 if (!err)
3166 mptcp_copy_inaddrs(sock->sk, ssock->sk);
3167
3168unlock:
3169 release_sock(sock->sk);
3170 return err;
3171}
3172
3173static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
3174 int flags, bool kern)
3175{
3176 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3177 struct socket *ssock;
3178 int err;
3179
3180 pr_debug("msk=%p", msk);
3181
3182 lock_sock(sock->sk);
3183 if (sock->sk->sk_state != TCP_LISTEN)
3184 goto unlock_fail;
3185
3186 ssock = __mptcp_nmpc_socket(msk);
3187 if (!ssock)
3188 goto unlock_fail;
3189
3190 clear_bit(MPTCP_DATA_READY, &msk->flags);
3191 sock_hold(ssock->sk);
3192 release_sock(sock->sk);
3193
3194 err = ssock->ops->accept(sock, newsock, flags, kern);
3195 if (err == 0 && !mptcp_is_tcpsk(newsock->sk)) {
3196 struct mptcp_sock *msk = mptcp_sk(newsock->sk);
3197 struct mptcp_subflow_context *subflow;
3198 struct sock *newsk = newsock->sk;
3199
3200 lock_sock(newsk);
3201
3202 /* PM/worker can now acquire the first subflow socket
3203 * lock without racing with listener queue cleanup,
3204 * we can notify it, if needed.
3205 *
3206 * Even if remote has reset the initial subflow by now
3207 * the refcnt is still at least one.
3208 */
3209 subflow = mptcp_subflow_ctx(msk->first);
3210 list_add(&subflow->node, &msk->conn_list);
3211 sock_hold(msk->first);
3212 if (mptcp_is_fully_established(newsk))
3213 mptcp_pm_fully_established(msk, msk->first, GFP_KERNEL);
3214
3215 mptcp_copy_inaddrs(newsk, msk->first);
3216 mptcp_rcv_space_init(msk, msk->first);
3217 mptcp_propagate_sndbuf(newsk, msk->first);
3218
3219 /* set ssk->sk_socket of accept()ed flows to mptcp socket.
3220 * This is needed so NOSPACE flag can be set from tcp stack.
3221 */
3222 mptcp_flush_join_list(msk);
3223 mptcp_for_each_subflow(msk, subflow) {
3224 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3225
3226 if (!ssk->sk_socket)
3227 mptcp_sock_graft(ssk, newsock);
3228 }
3229 release_sock(newsk);
3230 }
3231
3232 if (inet_csk_listen_poll(ssock->sk))
3233 set_bit(MPTCP_DATA_READY, &msk->flags);
3234 sock_put(ssock->sk);
3235 return err;
3236
3237unlock_fail:
3238 release_sock(sock->sk);
3239 return -EINVAL;
3240}
3241
3242static __poll_t mptcp_check_readable(struct mptcp_sock *msk)
3243{
3244 /* Concurrent splices from sk_receive_queue into receive_queue will
3245 * always show at least one non-empty queue when checked in this order.
3246 */
3247 if (skb_queue_empty_lockless(&((struct sock *)msk)->sk_receive_queue) &&
3248 skb_queue_empty_lockless(&msk->receive_queue))
3249 return 0;
3250
3251 return EPOLLIN | EPOLLRDNORM;
3252}
3253
3254static __poll_t mptcp_check_writeable(struct mptcp_sock *msk)
3255{
3256 struct sock *sk = (struct sock *)msk;
3257
3258 if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
3259 return EPOLLOUT | EPOLLWRNORM;
3260
3261 if (sk_stream_is_writeable(sk))
3262 return EPOLLOUT | EPOLLWRNORM;
3263
3264 mptcp_set_nospace(sk);
3265 smp_mb__after_atomic(); /* msk->flags is changed by write_space cb */
3266 if (sk_stream_is_writeable(sk))
3267 return EPOLLOUT | EPOLLWRNORM;
3268
3269 return 0;
3270}
3271
3272static __poll_t mptcp_poll(struct file *file, struct socket *sock,
3273 struct poll_table_struct *wait)
3274{
3275 struct sock *sk = sock->sk;
3276 struct mptcp_sock *msk;
3277 __poll_t mask = 0;
3278 int state;
3279
3280 msk = mptcp_sk(sk);
3281 sock_poll_wait(file, sock, wait);
3282
3283 state = inet_sk_state_load(sk);
3284 pr_debug("msk=%p state=%d flags=%lx", msk, state, msk->flags);
3285 if (state == TCP_LISTEN)
3286 return test_bit(MPTCP_DATA_READY, &msk->flags) ? EPOLLIN | EPOLLRDNORM : 0;
3287
3288 if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) {
3289 mask |= mptcp_check_readable(msk);
3290 mask |= mptcp_check_writeable(msk);
3291 }
3292 if (sk->sk_shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
3293 mask |= EPOLLHUP;
3294 if (sk->sk_shutdown & RCV_SHUTDOWN)
3295 mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
3296
3297 /* This barrier is coupled with smp_wmb() in tcp_reset() */
3298 smp_rmb();
3299 if (sk->sk_err)
3300 mask |= EPOLLERR;
3301
3302 return mask;
3303}
3304
3305static const struct proto_ops mptcp_stream_ops = {
3306 .family = PF_INET,
3307 .owner = THIS_MODULE,
3308 .release = inet_release,
3309 .bind = mptcp_bind,
3310 .connect = mptcp_stream_connect,
3311 .socketpair = sock_no_socketpair,
3312 .accept = mptcp_stream_accept,
3313 .getname = inet_getname,
3314 .poll = mptcp_poll,
3315 .ioctl = inet_ioctl,
3316 .gettstamp = sock_gettstamp,
3317 .listen = mptcp_listen,
3318 .shutdown = inet_shutdown,
3319 .setsockopt = sock_common_setsockopt,
3320 .getsockopt = sock_common_getsockopt,
3321 .sendmsg = inet_sendmsg,
3322 .recvmsg = inet_recvmsg,
3323 .mmap = sock_no_mmap,
3324 .sendpage = inet_sendpage,
3325};
3326
3327static struct inet_protosw mptcp_protosw = {
3328 .type = SOCK_STREAM,
3329 .protocol = IPPROTO_MPTCP,
3330 .prot = &mptcp_prot,
3331 .ops = &mptcp_stream_ops,
3332 .flags = INET_PROTOSW_ICSK,
3333};
3334
3335static int mptcp_napi_poll(struct napi_struct *napi, int budget)
3336{
3337 struct mptcp_delegated_action *delegated;
3338 struct mptcp_subflow_context *subflow;
3339 int work_done = 0;
3340
3341 delegated = container_of(napi, struct mptcp_delegated_action, napi);
3342 while ((subflow = mptcp_subflow_delegated_next(delegated)) != NULL) {
3343 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3344
3345 bh_lock_sock_nested(ssk);
3346 if (!sock_owned_by_user(ssk) &&
3347 mptcp_subflow_has_delegated_action(subflow))
3348 mptcp_subflow_process_delegated(ssk);
3349 /* ... elsewhere tcp_release_cb_override already processed
3350 * the action or will do at next release_sock().
3351 * In both case must dequeue the subflow here - on the same
3352 * CPU that scheduled it.
3353 */
3354 bh_unlock_sock(ssk);
3355 sock_put(ssk);
3356
3357 if (++work_done == budget)
3358 return budget;
3359 }
3360
3361 /* always provide a 0 'work_done' argument, so that napi_complete_done
3362 * will not try accessing the NULL napi->dev ptr
3363 */
3364 napi_complete_done(napi, 0);
3365 return work_done;
3366}
3367
3368void __init mptcp_proto_init(void)
3369{
3370 struct mptcp_delegated_action *delegated;
3371 int cpu;
3372
3373 mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo;
3374
3375 if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL))
3376 panic("Failed to allocate MPTCP pcpu counter\n");
3377
3378 init_dummy_netdev(&mptcp_napi_dev);
3379 for_each_possible_cpu(cpu) {
3380 delegated = per_cpu_ptr(&mptcp_delegated_actions, cpu);
3381 INIT_LIST_HEAD(&delegated->head);
3382 netif_tx_napi_add(&mptcp_napi_dev, &delegated->napi, mptcp_napi_poll,
3383 NAPI_POLL_WEIGHT);
3384 napi_enable(&delegated->napi);
3385 }
3386
3387 mptcp_subflow_init();
3388 mptcp_pm_init();
3389 mptcp_token_init();
3390
3391 if (proto_register(&mptcp_prot, 1) != 0)
3392 panic("Failed to register MPTCP proto.\n");
3393
3394 inet_register_protosw(&mptcp_protosw);
3395
3396 BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb));
3397}
3398
3399#if IS_ENABLED(CONFIG_MPTCP_IPV6)
3400static const struct proto_ops mptcp_v6_stream_ops = {
3401 .family = PF_INET6,
3402 .owner = THIS_MODULE,
3403 .release = inet6_release,
3404 .bind = mptcp_bind,
3405 .connect = mptcp_stream_connect,
3406 .socketpair = sock_no_socketpair,
3407 .accept = mptcp_stream_accept,
3408 .getname = inet6_getname,
3409 .poll = mptcp_poll,
3410 .ioctl = inet6_ioctl,
3411 .gettstamp = sock_gettstamp,
3412 .listen = mptcp_listen,
3413 .shutdown = inet_shutdown,
3414 .setsockopt = sock_common_setsockopt,
3415 .getsockopt = sock_common_getsockopt,
3416 .sendmsg = inet6_sendmsg,
3417 .recvmsg = inet6_recvmsg,
3418 .mmap = sock_no_mmap,
3419 .sendpage = inet_sendpage,
3420#ifdef CONFIG_COMPAT
3421 .compat_ioctl = inet6_compat_ioctl,
3422#endif
3423};
3424
3425static struct proto mptcp_v6_prot;
3426
3427static void mptcp_v6_destroy(struct sock *sk)
3428{
3429 mptcp_destroy(sk);
3430 inet6_destroy_sock(sk);
3431}
3432
3433static struct inet_protosw mptcp_v6_protosw = {
3434 .type = SOCK_STREAM,
3435 .protocol = IPPROTO_MPTCP,
3436 .prot = &mptcp_v6_prot,
3437 .ops = &mptcp_v6_stream_ops,
3438 .flags = INET_PROTOSW_ICSK,
3439};
3440
3441int __init mptcp_proto_v6_init(void)
3442{
3443 int err;
3444
3445 mptcp_v6_prot = mptcp_prot;
3446 strcpy(mptcp_v6_prot.name, "MPTCPv6");
3447 mptcp_v6_prot.slab = NULL;
3448 mptcp_v6_prot.destroy = mptcp_v6_destroy;
3449 mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock);
3450
3451 err = proto_register(&mptcp_v6_prot, 1);
3452 if (err)
3453 return err;
3454
3455 err = inet6_register_protosw(&mptcp_v6_protosw);
3456 if (err)
3457 proto_unregister(&mptcp_v6_prot);
3458
3459 return err;
3460}
3461#endif