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)
33 struct mptcp6_sock {
34 struct mptcp_sock msk;
35 struct ipv6_pinfo np;
36 };
37 #endif
38
39 enum {
40 MPTCP_CMSG_TS = BIT(0),
41 MPTCP_CMSG_INQ = BIT(1),
42 };
43
44 static struct percpu_counter mptcp_sockets_allocated ____cacheline_aligned_in_smp;
45
46 static void __mptcp_destroy_sock(struct sock *sk);
47 static void mptcp_check_send_data_fin(struct sock *sk);
48
49 DEFINE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
50 static struct net_device mptcp_napi_dev;
51
52 /* Returns end sequence number of the receiver's advertised window */
mptcp_wnd_end(const struct mptcp_sock * msk)53 static u64 mptcp_wnd_end(const struct mptcp_sock *msk)
54 {
55 return READ_ONCE(msk->wnd_end);
56 }
57
mptcp_fallback_tcp_ops(const struct sock * sk)58 static 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
__mptcp_socket_create(struct mptcp_sock * msk)68 static 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 */
__mptcp_nmpc_sk(struct mptcp_sock * msk)98 struct 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
mptcp_drop(struct sock * sk,struct sk_buff * skb)115 static void mptcp_drop(struct sock *sk, struct sk_buff *skb)
116 {
117 sk_drops_add(sk, skb);
118 __kfree_skb(skb);
119 }
120
mptcp_rmem_fwd_alloc_add(struct sock * sk,int size)121 static 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
mptcp_rmem_charge(struct sock * sk,int size)127 static void mptcp_rmem_charge(struct sock *sk, int size)
128 {
129 mptcp_rmem_fwd_alloc_add(sk, -size);
130 }
131
mptcp_try_coalesce(struct sock * sk,struct sk_buff * to,struct sk_buff * from)132 static 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 !skb_try_coalesce(to, from, &fragstolen, &delta))
140 return false;
141
142 pr_debug("colesced seq %llx into %llx new len %d new end seq %llx\n",
143 MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq,
144 to->len, MPTCP_SKB_CB(from)->end_seq);
145 MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq;
146
147 /* note the fwd memory can reach a negative value after accounting
148 * for the delta, but the later skb free will restore a non
149 * negative one
150 */
151 atomic_add(delta, &sk->sk_rmem_alloc);
152 mptcp_rmem_charge(sk, delta);
153 kfree_skb_partial(from, fragstolen);
154
155 return true;
156 }
157
mptcp_ooo_try_coalesce(struct mptcp_sock * msk,struct sk_buff * to,struct sk_buff * from)158 static bool mptcp_ooo_try_coalesce(struct mptcp_sock *msk, struct sk_buff *to,
159 struct sk_buff *from)
160 {
161 if (MPTCP_SKB_CB(from)->map_seq != MPTCP_SKB_CB(to)->end_seq)
162 return false;
163
164 return mptcp_try_coalesce((struct sock *)msk, to, from);
165 }
166
__mptcp_rmem_reclaim(struct sock * sk,int amount)167 static void __mptcp_rmem_reclaim(struct sock *sk, int amount)
168 {
169 amount >>= PAGE_SHIFT;
170 mptcp_rmem_charge(sk, amount << PAGE_SHIFT);
171 __sk_mem_reduce_allocated(sk, amount);
172 }
173
mptcp_rmem_uncharge(struct sock * sk,int size)174 static void mptcp_rmem_uncharge(struct sock *sk, int size)
175 {
176 struct mptcp_sock *msk = mptcp_sk(sk);
177 int reclaimable;
178
179 mptcp_rmem_fwd_alloc_add(sk, size);
180 reclaimable = msk->rmem_fwd_alloc - sk_unused_reserved_mem(sk);
181
182 /* see sk_mem_uncharge() for the rationale behind the following schema */
183 if (unlikely(reclaimable >= PAGE_SIZE))
184 __mptcp_rmem_reclaim(sk, reclaimable);
185 }
186
mptcp_rfree(struct sk_buff * skb)187 static void mptcp_rfree(struct sk_buff *skb)
188 {
189 unsigned int len = skb->truesize;
190 struct sock *sk = skb->sk;
191
192 atomic_sub(len, &sk->sk_rmem_alloc);
193 mptcp_rmem_uncharge(sk, len);
194 }
195
mptcp_set_owner_r(struct sk_buff * skb,struct sock * sk)196 void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk)
197 {
198 skb_orphan(skb);
199 skb->sk = sk;
200 skb->destructor = mptcp_rfree;
201 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
202 mptcp_rmem_charge(sk, skb->truesize);
203 }
204
205 /* "inspired" by tcp_data_queue_ofo(), main differences:
206 * - use mptcp seqs
207 * - don't cope with sacks
208 */
mptcp_data_queue_ofo(struct mptcp_sock * msk,struct sk_buff * skb)209 static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb)
210 {
211 struct sock *sk = (struct sock *)msk;
212 struct rb_node **p, *parent;
213 u64 seq, end_seq, max_seq;
214 struct sk_buff *skb1;
215
216 seq = MPTCP_SKB_CB(skb)->map_seq;
217 end_seq = MPTCP_SKB_CB(skb)->end_seq;
218 max_seq = atomic64_read(&msk->rcv_wnd_sent);
219
220 pr_debug("msk=%p seq=%llx limit=%llx empty=%d\n", msk, seq, max_seq,
221 RB_EMPTY_ROOT(&msk->out_of_order_queue));
222 if (after64(end_seq, max_seq)) {
223 /* out of window */
224 mptcp_drop(sk, skb);
225 pr_debug("oow by %lld, rcv_wnd_sent %llu\n",
226 (unsigned long long)end_seq - (unsigned long)max_seq,
227 (unsigned long long)atomic64_read(&msk->rcv_wnd_sent));
228 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_NODSSWINDOW);
229 return;
230 }
231
232 p = &msk->out_of_order_queue.rb_node;
233 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUE);
234 if (RB_EMPTY_ROOT(&msk->out_of_order_queue)) {
235 rb_link_node(&skb->rbnode, NULL, p);
236 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
237 msk->ooo_last_skb = skb;
238 goto end;
239 }
240
241 /* with 2 subflows, adding at end of ooo queue is quite likely
242 * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup.
243 */
244 if (mptcp_ooo_try_coalesce(msk, msk->ooo_last_skb, skb)) {
245 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
246 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
247 return;
248 }
249
250 /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */
251 if (!before64(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) {
252 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
253 parent = &msk->ooo_last_skb->rbnode;
254 p = &parent->rb_right;
255 goto insert;
256 }
257
258 /* Find place to insert this segment. Handle overlaps on the way. */
259 parent = NULL;
260 while (*p) {
261 parent = *p;
262 skb1 = rb_to_skb(parent);
263 if (before64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
264 p = &parent->rb_left;
265 continue;
266 }
267 if (before64(seq, MPTCP_SKB_CB(skb1)->end_seq)) {
268 if (!after64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) {
269 /* All the bits are present. Drop. */
270 mptcp_drop(sk, skb);
271 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
272 return;
273 }
274 if (after64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
275 /* partial overlap:
276 * | skb |
277 * | skb1 |
278 * continue traversing
279 */
280 } else {
281 /* skb's seq == skb1's seq and skb covers skb1.
282 * Replace skb1 with skb.
283 */
284 rb_replace_node(&skb1->rbnode, &skb->rbnode,
285 &msk->out_of_order_queue);
286 mptcp_drop(sk, skb1);
287 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
288 goto merge_right;
289 }
290 } else if (mptcp_ooo_try_coalesce(msk, skb1, skb)) {
291 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
292 return;
293 }
294 p = &parent->rb_right;
295 }
296
297 insert:
298 /* Insert segment into RB tree. */
299 rb_link_node(&skb->rbnode, parent, p);
300 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
301
302 merge_right:
303 /* Remove other segments covered by skb. */
304 while ((skb1 = skb_rb_next(skb)) != NULL) {
305 if (before64(end_seq, MPTCP_SKB_CB(skb1)->end_seq))
306 break;
307 rb_erase(&skb1->rbnode, &msk->out_of_order_queue);
308 mptcp_drop(sk, skb1);
309 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
310 }
311 /* If there is no skb after us, we are the last_skb ! */
312 if (!skb1)
313 msk->ooo_last_skb = skb;
314
315 end:
316 skb_condense(skb);
317 mptcp_set_owner_r(skb, sk);
318 }
319
mptcp_rmem_schedule(struct sock * sk,struct sock * ssk,int size)320 static bool mptcp_rmem_schedule(struct sock *sk, struct sock *ssk, int size)
321 {
322 struct mptcp_sock *msk = mptcp_sk(sk);
323 int amt, amount;
324
325 if (size <= msk->rmem_fwd_alloc)
326 return true;
327
328 size -= msk->rmem_fwd_alloc;
329 amt = sk_mem_pages(size);
330 amount = amt << PAGE_SHIFT;
331 if (!__sk_mem_raise_allocated(sk, size, amt, SK_MEM_RECV))
332 return false;
333
334 mptcp_rmem_fwd_alloc_add(sk, amount);
335 return true;
336 }
337
__mptcp_move_skb(struct mptcp_sock * msk,struct sock * ssk,struct sk_buff * skb,unsigned int offset,size_t copy_len)338 static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk,
339 struct sk_buff *skb, unsigned int offset,
340 size_t copy_len)
341 {
342 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
343 struct sock *sk = (struct sock *)msk;
344 struct sk_buff *tail;
345 bool has_rxtstamp;
346
347 __skb_unlink(skb, &ssk->sk_receive_queue);
348
349 skb_ext_reset(skb);
350 skb_orphan(skb);
351
352 /* try to fetch required memory from subflow */
353 if (!mptcp_rmem_schedule(sk, ssk, skb->truesize)) {
354 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED);
355 goto drop;
356 }
357
358 has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp;
359
360 /* the skb map_seq accounts for the skb offset:
361 * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq
362 * value
363 */
364 MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow);
365 MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len;
366 MPTCP_SKB_CB(skb)->offset = offset;
367 MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp;
368
369 if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) {
370 /* in sequence */
371 msk->bytes_received += copy_len;
372 WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len);
373 tail = skb_peek_tail(&sk->sk_receive_queue);
374 if (tail && mptcp_try_coalesce(sk, tail, skb))
375 return true;
376
377 mptcp_set_owner_r(skb, sk);
378 __skb_queue_tail(&sk->sk_receive_queue, skb);
379 return true;
380 } else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) {
381 mptcp_data_queue_ofo(msk, skb);
382 return false;
383 }
384
385 /* old data, keep it simple and drop the whole pkt, sender
386 * will retransmit as needed, if needed.
387 */
388 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
389 drop:
390 mptcp_drop(sk, skb);
391 return false;
392 }
393
mptcp_stop_rtx_timer(struct sock * sk)394 static void mptcp_stop_rtx_timer(struct sock *sk)
395 {
396 struct inet_connection_sock *icsk = inet_csk(sk);
397
398 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
399 mptcp_sk(sk)->timer_ival = 0;
400 }
401
mptcp_close_wake_up(struct sock * sk)402 static void mptcp_close_wake_up(struct sock *sk)
403 {
404 if (sock_flag(sk, SOCK_DEAD))
405 return;
406
407 sk->sk_state_change(sk);
408 if (sk->sk_shutdown == SHUTDOWN_MASK ||
409 sk->sk_state == TCP_CLOSE)
410 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
411 else
412 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
413 }
414
415 /* called under the msk socket lock */
mptcp_pending_data_fin_ack(struct sock * sk)416 static bool mptcp_pending_data_fin_ack(struct sock *sk)
417 {
418 struct mptcp_sock *msk = mptcp_sk(sk);
419
420 return ((1 << sk->sk_state) &
421 (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) &&
422 msk->write_seq == READ_ONCE(msk->snd_una);
423 }
424
mptcp_check_data_fin_ack(struct sock * sk)425 static void mptcp_check_data_fin_ack(struct sock *sk)
426 {
427 struct mptcp_sock *msk = mptcp_sk(sk);
428
429 /* Look for an acknowledged DATA_FIN */
430 if (mptcp_pending_data_fin_ack(sk)) {
431 WRITE_ONCE(msk->snd_data_fin_enable, 0);
432
433 switch (sk->sk_state) {
434 case TCP_FIN_WAIT1:
435 mptcp_set_state(sk, TCP_FIN_WAIT2);
436 break;
437 case TCP_CLOSING:
438 case TCP_LAST_ACK:
439 mptcp_set_state(sk, TCP_CLOSE);
440 break;
441 }
442
443 mptcp_close_wake_up(sk);
444 }
445 }
446
447 /* can be called with no lock acquired */
mptcp_pending_data_fin(struct sock * sk,u64 * seq)448 static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq)
449 {
450 struct mptcp_sock *msk = mptcp_sk(sk);
451
452 if (READ_ONCE(msk->rcv_data_fin) &&
453 ((1 << inet_sk_state_load(sk)) &
454 (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) {
455 u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq);
456
457 if (READ_ONCE(msk->ack_seq) == rcv_data_fin_seq) {
458 if (seq)
459 *seq = rcv_data_fin_seq;
460
461 return true;
462 }
463 }
464
465 return false;
466 }
467
mptcp_set_datafin_timeout(struct sock * sk)468 static void mptcp_set_datafin_timeout(struct sock *sk)
469 {
470 struct inet_connection_sock *icsk = inet_csk(sk);
471 u32 retransmits;
472
473 retransmits = min_t(u32, icsk->icsk_retransmits,
474 ilog2(TCP_RTO_MAX / TCP_RTO_MIN));
475
476 mptcp_sk(sk)->timer_ival = TCP_RTO_MIN << retransmits;
477 }
478
__mptcp_set_timeout(struct sock * sk,long tout)479 static void __mptcp_set_timeout(struct sock *sk, long tout)
480 {
481 mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
482 }
483
mptcp_timeout_from_subflow(const struct mptcp_subflow_context * subflow)484 static long mptcp_timeout_from_subflow(const struct mptcp_subflow_context *subflow)
485 {
486 const struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
487
488 return inet_csk(ssk)->icsk_pending && !subflow->stale_count ?
489 inet_csk(ssk)->icsk_timeout - jiffies : 0;
490 }
491
mptcp_set_timeout(struct sock * sk)492 static void mptcp_set_timeout(struct sock *sk)
493 {
494 struct mptcp_subflow_context *subflow;
495 long tout = 0;
496
497 mptcp_for_each_subflow(mptcp_sk(sk), subflow)
498 tout = max(tout, mptcp_timeout_from_subflow(subflow));
499 __mptcp_set_timeout(sk, tout);
500 }
501
tcp_can_send_ack(const struct sock * ssk)502 static inline bool tcp_can_send_ack(const struct sock *ssk)
503 {
504 return !((1 << inet_sk_state_load(ssk)) &
505 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE | TCPF_LISTEN));
506 }
507
__mptcp_subflow_send_ack(struct sock * ssk)508 void __mptcp_subflow_send_ack(struct sock *ssk)
509 {
510 if (tcp_can_send_ack(ssk))
511 tcp_send_ack(ssk);
512 }
513
mptcp_subflow_send_ack(struct sock * ssk)514 static void mptcp_subflow_send_ack(struct sock *ssk)
515 {
516 bool slow;
517
518 slow = lock_sock_fast(ssk);
519 __mptcp_subflow_send_ack(ssk);
520 unlock_sock_fast(ssk, slow);
521 }
522
mptcp_send_ack(struct mptcp_sock * msk)523 static void mptcp_send_ack(struct mptcp_sock *msk)
524 {
525 struct mptcp_subflow_context *subflow;
526
527 mptcp_for_each_subflow(msk, subflow)
528 mptcp_subflow_send_ack(mptcp_subflow_tcp_sock(subflow));
529 }
530
mptcp_subflow_cleanup_rbuf(struct sock * ssk)531 static void mptcp_subflow_cleanup_rbuf(struct sock *ssk)
532 {
533 bool slow;
534
535 slow = lock_sock_fast(ssk);
536 if (tcp_can_send_ack(ssk))
537 tcp_cleanup_rbuf(ssk, 1);
538 unlock_sock_fast(ssk, slow);
539 }
540
mptcp_subflow_could_cleanup(const struct sock * ssk,bool rx_empty)541 static bool mptcp_subflow_could_cleanup(const struct sock *ssk, bool rx_empty)
542 {
543 const struct inet_connection_sock *icsk = inet_csk(ssk);
544 u8 ack_pending = READ_ONCE(icsk->icsk_ack.pending);
545 const struct tcp_sock *tp = tcp_sk(ssk);
546
547 return (ack_pending & ICSK_ACK_SCHED) &&
548 ((READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->rcv_wup) >
549 READ_ONCE(icsk->icsk_ack.rcv_mss)) ||
550 (rx_empty && ack_pending &
551 (ICSK_ACK_PUSHED2 | ICSK_ACK_PUSHED)));
552 }
553
mptcp_cleanup_rbuf(struct mptcp_sock * msk)554 static void mptcp_cleanup_rbuf(struct mptcp_sock *msk)
555 {
556 int old_space = READ_ONCE(msk->old_wspace);
557 struct mptcp_subflow_context *subflow;
558 struct sock *sk = (struct sock *)msk;
559 int space = __mptcp_space(sk);
560 bool cleanup, rx_empty;
561
562 cleanup = (space > 0) && (space >= (old_space << 1));
563 rx_empty = !__mptcp_rmem(sk);
564
565 mptcp_for_each_subflow(msk, subflow) {
566 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
567
568 if (cleanup || mptcp_subflow_could_cleanup(ssk, rx_empty))
569 mptcp_subflow_cleanup_rbuf(ssk);
570 }
571 }
572
mptcp_check_data_fin(struct sock * sk)573 static bool mptcp_check_data_fin(struct sock *sk)
574 {
575 struct mptcp_sock *msk = mptcp_sk(sk);
576 u64 rcv_data_fin_seq;
577 bool ret = false;
578
579 /* Need to ack a DATA_FIN received from a peer while this side
580 * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2.
581 * msk->rcv_data_fin was set when parsing the incoming options
582 * at the subflow level and the msk lock was not held, so this
583 * is the first opportunity to act on the DATA_FIN and change
584 * the msk state.
585 *
586 * If we are caught up to the sequence number of the incoming
587 * DATA_FIN, send the DATA_ACK now and do state transition. If
588 * not caught up, do nothing and let the recv code send DATA_ACK
589 * when catching up.
590 */
591
592 if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) {
593 WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1);
594 WRITE_ONCE(msk->rcv_data_fin, 0);
595
596 WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | RCV_SHUTDOWN);
597 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
598
599 switch (sk->sk_state) {
600 case TCP_ESTABLISHED:
601 mptcp_set_state(sk, TCP_CLOSE_WAIT);
602 break;
603 case TCP_FIN_WAIT1:
604 mptcp_set_state(sk, TCP_CLOSING);
605 break;
606 case TCP_FIN_WAIT2:
607 mptcp_set_state(sk, TCP_CLOSE);
608 break;
609 default:
610 /* Other states not expected */
611 WARN_ON_ONCE(1);
612 break;
613 }
614
615 ret = true;
616 if (!__mptcp_check_fallback(msk))
617 mptcp_send_ack(msk);
618 mptcp_close_wake_up(sk);
619 }
620 return ret;
621 }
622
__mptcp_move_skbs_from_subflow(struct mptcp_sock * msk,struct sock * ssk,unsigned int * bytes)623 static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
624 struct sock *ssk,
625 unsigned int *bytes)
626 {
627 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
628 struct sock *sk = (struct sock *)msk;
629 unsigned int moved = 0;
630 bool more_data_avail;
631 struct tcp_sock *tp;
632 bool done = false;
633 int sk_rbuf;
634
635 sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
636
637 if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
638 int ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
639
640 if (unlikely(ssk_rbuf > sk_rbuf)) {
641 WRITE_ONCE(sk->sk_rcvbuf, ssk_rbuf);
642 sk_rbuf = ssk_rbuf;
643 }
644 }
645
646 pr_debug("msk=%p ssk=%p\n", msk, ssk);
647 tp = tcp_sk(ssk);
648 do {
649 u32 map_remaining, offset;
650 u32 seq = tp->copied_seq;
651 struct sk_buff *skb;
652 bool fin;
653
654 /* try to move as much data as available */
655 map_remaining = subflow->map_data_len -
656 mptcp_subflow_get_map_offset(subflow);
657
658 skb = skb_peek(&ssk->sk_receive_queue);
659 if (!skb) {
660 /* With racing move_skbs_to_msk() and __mptcp_move_skbs(),
661 * a different CPU can have already processed the pending
662 * data, stop here or we can enter an infinite loop
663 */
664 if (!moved)
665 done = true;
666 break;
667 }
668
669 if (__mptcp_check_fallback(msk)) {
670 /* Under fallback skbs have no MPTCP extension and TCP could
671 * collapse them between the dummy map creation and the
672 * current dequeue. Be sure to adjust the map size.
673 */
674 map_remaining = skb->len;
675 subflow->map_data_len = skb->len;
676 }
677
678 offset = seq - TCP_SKB_CB(skb)->seq;
679 fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
680 if (fin) {
681 done = true;
682 seq++;
683 }
684
685 if (offset < skb->len) {
686 size_t len = skb->len - offset;
687
688 if (tp->urg_data)
689 done = true;
690
691 if (__mptcp_move_skb(msk, ssk, skb, offset, len))
692 moved += len;
693 seq += len;
694
695 if (WARN_ON_ONCE(map_remaining < len))
696 break;
697 } else {
698 WARN_ON_ONCE(!fin);
699 sk_eat_skb(ssk, skb);
700 done = true;
701 }
702
703 WRITE_ONCE(tp->copied_seq, seq);
704 more_data_avail = mptcp_subflow_data_available(ssk);
705
706 if (atomic_read(&sk->sk_rmem_alloc) > sk_rbuf) {
707 done = true;
708 break;
709 }
710 } while (more_data_avail);
711
712 if (moved > 0)
713 msk->last_data_recv = tcp_jiffies32;
714 *bytes += moved;
715 return done;
716 }
717
__mptcp_ofo_queue(struct mptcp_sock * msk)718 static bool __mptcp_ofo_queue(struct mptcp_sock *msk)
719 {
720 struct sock *sk = (struct sock *)msk;
721 struct sk_buff *skb, *tail;
722 bool moved = false;
723 struct rb_node *p;
724 u64 end_seq;
725
726 p = rb_first(&msk->out_of_order_queue);
727 pr_debug("msk=%p empty=%d\n", msk, RB_EMPTY_ROOT(&msk->out_of_order_queue));
728 while (p) {
729 skb = rb_to_skb(p);
730 if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq))
731 break;
732
733 p = rb_next(p);
734 rb_erase(&skb->rbnode, &msk->out_of_order_queue);
735
736 if (unlikely(!after64(MPTCP_SKB_CB(skb)->end_seq,
737 msk->ack_seq))) {
738 mptcp_drop(sk, skb);
739 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
740 continue;
741 }
742
743 end_seq = MPTCP_SKB_CB(skb)->end_seq;
744 tail = skb_peek_tail(&sk->sk_receive_queue);
745 if (!tail || !mptcp_ooo_try_coalesce(msk, tail, skb)) {
746 int delta = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq;
747
748 /* skip overlapping data, if any */
749 pr_debug("uncoalesced seq=%llx ack seq=%llx delta=%d\n",
750 MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq,
751 delta);
752 MPTCP_SKB_CB(skb)->offset += delta;
753 MPTCP_SKB_CB(skb)->map_seq += delta;
754 __skb_queue_tail(&sk->sk_receive_queue, skb);
755 }
756 msk->bytes_received += end_seq - msk->ack_seq;
757 WRITE_ONCE(msk->ack_seq, end_seq);
758 moved = true;
759 }
760 return moved;
761 }
762
__mptcp_subflow_error_report(struct sock * sk,struct sock * ssk)763 static bool __mptcp_subflow_error_report(struct sock *sk, struct sock *ssk)
764 {
765 int err = sock_error(ssk);
766 int ssk_state;
767
768 if (!err)
769 return false;
770
771 /* only propagate errors on fallen-back sockets or
772 * on MPC connect
773 */
774 if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(mptcp_sk(sk)))
775 return false;
776
777 /* We need to propagate only transition to CLOSE state.
778 * Orphaned socket will see such state change via
779 * subflow_sched_work_if_closed() and that path will properly
780 * destroy the msk as needed.
781 */
782 ssk_state = inet_sk_state_load(ssk);
783 if (ssk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DEAD))
784 mptcp_set_state(sk, ssk_state);
785 WRITE_ONCE(sk->sk_err, -err);
786
787 /* This barrier is coupled with smp_rmb() in mptcp_poll() */
788 smp_wmb();
789 sk_error_report(sk);
790 return true;
791 }
792
__mptcp_error_report(struct sock * sk)793 void __mptcp_error_report(struct sock *sk)
794 {
795 struct mptcp_subflow_context *subflow;
796 struct mptcp_sock *msk = mptcp_sk(sk);
797
798 mptcp_for_each_subflow(msk, subflow)
799 if (__mptcp_subflow_error_report(sk, mptcp_subflow_tcp_sock(subflow)))
800 break;
801 }
802
803 /* In most cases we will be able to lock the mptcp socket. If its already
804 * owned, we need to defer to the work queue to avoid ABBA deadlock.
805 */
move_skbs_to_msk(struct mptcp_sock * msk,struct sock * ssk)806 static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk)
807 {
808 struct sock *sk = (struct sock *)msk;
809 unsigned int moved = 0;
810
811 __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
812 __mptcp_ofo_queue(msk);
813 if (unlikely(ssk->sk_err)) {
814 if (!sock_owned_by_user(sk))
815 __mptcp_error_report(sk);
816 else
817 __set_bit(MPTCP_ERROR_REPORT, &msk->cb_flags);
818 }
819
820 /* If the moves have caught up with the DATA_FIN sequence number
821 * it's time to ack the DATA_FIN and change socket state, but
822 * this is not a good place to change state. Let the workqueue
823 * do it.
824 */
825 if (mptcp_pending_data_fin(sk, NULL))
826 mptcp_schedule_work(sk);
827 return moved > 0;
828 }
829
mptcp_data_ready(struct sock * sk,struct sock * ssk)830 void mptcp_data_ready(struct sock *sk, struct sock *ssk)
831 {
832 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
833 struct mptcp_sock *msk = mptcp_sk(sk);
834 int sk_rbuf, ssk_rbuf;
835
836 /* The peer can send data while we are shutting down this
837 * subflow at msk destruction time, but we must avoid enqueuing
838 * more data to the msk receive queue
839 */
840 if (unlikely(subflow->disposable))
841 return;
842
843 ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
844 sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
845 if (unlikely(ssk_rbuf > sk_rbuf))
846 sk_rbuf = ssk_rbuf;
847
848 /* over limit? can't append more skbs to msk, Also, no need to wake-up*/
849 if (__mptcp_rmem(sk) > sk_rbuf)
850 return;
851
852 /* Wake-up the reader only for in-sequence data */
853 mptcp_data_lock(sk);
854 if (move_skbs_to_msk(msk, ssk) && mptcp_epollin_ready(sk))
855 sk->sk_data_ready(sk);
856 mptcp_data_unlock(sk);
857 }
858
mptcp_subflow_joined(struct mptcp_sock * msk,struct sock * ssk)859 static void mptcp_subflow_joined(struct mptcp_sock *msk, struct sock *ssk)
860 {
861 mptcp_subflow_ctx(ssk)->map_seq = READ_ONCE(msk->ack_seq);
862 WRITE_ONCE(msk->allow_infinite_fallback, false);
863 mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC);
864 }
865
__mptcp_finish_join(struct mptcp_sock * msk,struct sock * ssk)866 static bool __mptcp_finish_join(struct mptcp_sock *msk, struct sock *ssk)
867 {
868 struct sock *sk = (struct sock *)msk;
869
870 if (sk->sk_state != TCP_ESTABLISHED)
871 return false;
872
873 /* attach to msk socket only after we are sure we will deal with it
874 * at close time
875 */
876 if (sk->sk_socket && !ssk->sk_socket)
877 mptcp_sock_graft(ssk, sk->sk_socket);
878
879 mptcp_subflow_ctx(ssk)->subflow_id = msk->subflow_id++;
880 mptcp_sockopt_sync_locked(msk, ssk);
881 mptcp_subflow_joined(msk, ssk);
882 mptcp_stop_tout_timer(sk);
883 __mptcp_propagate_sndbuf(sk, ssk);
884 return true;
885 }
886
__mptcp_flush_join_list(struct sock * sk,struct list_head * join_list)887 static void __mptcp_flush_join_list(struct sock *sk, struct list_head *join_list)
888 {
889 struct mptcp_subflow_context *tmp, *subflow;
890 struct mptcp_sock *msk = mptcp_sk(sk);
891
892 list_for_each_entry_safe(subflow, tmp, join_list, node) {
893 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
894 bool slow = lock_sock_fast(ssk);
895
896 list_move_tail(&subflow->node, &msk->conn_list);
897 if (!__mptcp_finish_join(msk, ssk))
898 mptcp_subflow_reset(ssk);
899 unlock_sock_fast(ssk, slow);
900 }
901 }
902
mptcp_rtx_timer_pending(struct sock * sk)903 static bool mptcp_rtx_timer_pending(struct sock *sk)
904 {
905 return timer_pending(&inet_csk(sk)->icsk_retransmit_timer);
906 }
907
mptcp_reset_rtx_timer(struct sock * sk)908 static void mptcp_reset_rtx_timer(struct sock *sk)
909 {
910 struct inet_connection_sock *icsk = inet_csk(sk);
911 unsigned long tout;
912
913 /* prevent rescheduling on close */
914 if (unlikely(inet_sk_state_load(sk) == TCP_CLOSE))
915 return;
916
917 tout = mptcp_sk(sk)->timer_ival;
918 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout);
919 }
920
mptcp_schedule_work(struct sock * sk)921 bool mptcp_schedule_work(struct sock *sk)
922 {
923 if (inet_sk_state_load(sk) != TCP_CLOSE &&
924 schedule_work(&mptcp_sk(sk)->work)) {
925 /* each subflow already holds a reference to the sk, and the
926 * workqueue is invoked by a subflow, so sk can't go away here.
927 */
928 sock_hold(sk);
929 return true;
930 }
931 return false;
932 }
933
mptcp_subflow_recv_lookup(const struct mptcp_sock * msk)934 static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk)
935 {
936 struct mptcp_subflow_context *subflow;
937
938 msk_owned_by_me(msk);
939
940 mptcp_for_each_subflow(msk, subflow) {
941 if (READ_ONCE(subflow->data_avail))
942 return mptcp_subflow_tcp_sock(subflow);
943 }
944
945 return NULL;
946 }
947
mptcp_skb_can_collapse_to(u64 write_seq,const struct sk_buff * skb,const struct mptcp_ext * mpext)948 static bool mptcp_skb_can_collapse_to(u64 write_seq,
949 const struct sk_buff *skb,
950 const struct mptcp_ext *mpext)
951 {
952 if (!tcp_skb_can_collapse_to(skb))
953 return false;
954
955 /* can collapse only if MPTCP level sequence is in order and this
956 * mapping has not been xmitted yet
957 */
958 return mpext && mpext->data_seq + mpext->data_len == write_seq &&
959 !mpext->frozen;
960 }
961
962 /* we can append data to the given data frag if:
963 * - there is space available in the backing page_frag
964 * - the data frag tail matches the current page_frag free offset
965 * - the data frag end sequence number matches the current write seq
966 */
mptcp_frag_can_collapse_to(const struct mptcp_sock * msk,const struct page_frag * pfrag,const struct mptcp_data_frag * df)967 static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk,
968 const struct page_frag *pfrag,
969 const struct mptcp_data_frag *df)
970 {
971 return df && pfrag->page == df->page &&
972 pfrag->size - pfrag->offset > 0 &&
973 pfrag->offset == (df->offset + df->data_len) &&
974 df->data_seq + df->data_len == msk->write_seq;
975 }
976
dfrag_uncharge(struct sock * sk,int len)977 static void dfrag_uncharge(struct sock *sk, int len)
978 {
979 sk_mem_uncharge(sk, len);
980 sk_wmem_queued_add(sk, -len);
981 }
982
dfrag_clear(struct sock * sk,struct mptcp_data_frag * dfrag)983 static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag)
984 {
985 int len = dfrag->data_len + dfrag->overhead;
986
987 list_del(&dfrag->list);
988 dfrag_uncharge(sk, len);
989 put_page(dfrag->page);
990 }
991
992 /* called under both the msk socket lock and the data lock */
__mptcp_clean_una(struct sock * sk)993 static void __mptcp_clean_una(struct sock *sk)
994 {
995 struct mptcp_sock *msk = mptcp_sk(sk);
996 struct mptcp_data_frag *dtmp, *dfrag;
997 u64 snd_una;
998
999 snd_una = msk->snd_una;
1000 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) {
1001 if (after64(dfrag->data_seq + dfrag->data_len, snd_una))
1002 break;
1003
1004 if (unlikely(dfrag == msk->first_pending)) {
1005 /* in recovery mode can see ack after the current snd head */
1006 if (WARN_ON_ONCE(!msk->recovery))
1007 break;
1008
1009 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1010 }
1011
1012 dfrag_clear(sk, dfrag);
1013 }
1014
1015 dfrag = mptcp_rtx_head(sk);
1016 if (dfrag && after64(snd_una, dfrag->data_seq)) {
1017 u64 delta = snd_una - dfrag->data_seq;
1018
1019 /* prevent wrap around in recovery mode */
1020 if (unlikely(delta > dfrag->already_sent)) {
1021 if (WARN_ON_ONCE(!msk->recovery))
1022 goto out;
1023 if (WARN_ON_ONCE(delta > dfrag->data_len))
1024 goto out;
1025 dfrag->already_sent += delta - dfrag->already_sent;
1026 }
1027
1028 dfrag->data_seq += delta;
1029 dfrag->offset += delta;
1030 dfrag->data_len -= delta;
1031 dfrag->already_sent -= delta;
1032
1033 dfrag_uncharge(sk, delta);
1034 }
1035
1036 /* all retransmitted data acked, recovery completed */
1037 if (unlikely(msk->recovery) && after64(msk->snd_una, msk->recovery_snd_nxt))
1038 msk->recovery = false;
1039
1040 out:
1041 if (snd_una == msk->snd_nxt && snd_una == msk->write_seq) {
1042 if (mptcp_rtx_timer_pending(sk) && !mptcp_data_fin_enabled(msk))
1043 mptcp_stop_rtx_timer(sk);
1044 } else {
1045 mptcp_reset_rtx_timer(sk);
1046 }
1047
1048 if (mptcp_pending_data_fin_ack(sk))
1049 mptcp_schedule_work(sk);
1050 }
1051
__mptcp_clean_una_wakeup(struct sock * sk)1052 static void __mptcp_clean_una_wakeup(struct sock *sk)
1053 {
1054 lockdep_assert_held_once(&sk->sk_lock.slock);
1055
1056 __mptcp_clean_una(sk);
1057 mptcp_write_space(sk);
1058 }
1059
mptcp_clean_una_wakeup(struct sock * sk)1060 static void mptcp_clean_una_wakeup(struct sock *sk)
1061 {
1062 mptcp_data_lock(sk);
1063 __mptcp_clean_una_wakeup(sk);
1064 mptcp_data_unlock(sk);
1065 }
1066
mptcp_enter_memory_pressure(struct sock * sk)1067 static void mptcp_enter_memory_pressure(struct sock *sk)
1068 {
1069 struct mptcp_subflow_context *subflow;
1070 struct mptcp_sock *msk = mptcp_sk(sk);
1071 bool first = true;
1072
1073 mptcp_for_each_subflow(msk, subflow) {
1074 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
1075
1076 if (first)
1077 tcp_enter_memory_pressure(ssk);
1078 sk_stream_moderate_sndbuf(ssk);
1079
1080 first = false;
1081 }
1082 __mptcp_sync_sndbuf(sk);
1083 }
1084
1085 /* ensure we get enough memory for the frag hdr, beyond some minimal amount of
1086 * data
1087 */
mptcp_page_frag_refill(struct sock * sk,struct page_frag * pfrag)1088 static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag)
1089 {
1090 if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag),
1091 pfrag, sk->sk_allocation)))
1092 return true;
1093
1094 mptcp_enter_memory_pressure(sk);
1095 return false;
1096 }
1097
1098 static struct mptcp_data_frag *
mptcp_carve_data_frag(const struct mptcp_sock * msk,struct page_frag * pfrag,int orig_offset)1099 mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag,
1100 int orig_offset)
1101 {
1102 int offset = ALIGN(orig_offset, sizeof(long));
1103 struct mptcp_data_frag *dfrag;
1104
1105 dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset);
1106 dfrag->data_len = 0;
1107 dfrag->data_seq = msk->write_seq;
1108 dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag);
1109 dfrag->offset = offset + sizeof(struct mptcp_data_frag);
1110 dfrag->already_sent = 0;
1111 dfrag->page = pfrag->page;
1112
1113 return dfrag;
1114 }
1115
1116 struct mptcp_sendmsg_info {
1117 int mss_now;
1118 int size_goal;
1119 u16 limit;
1120 u16 sent;
1121 unsigned int flags;
1122 bool data_lock_held;
1123 };
1124
mptcp_check_allowed_size(const struct mptcp_sock * msk,struct sock * ssk,u64 data_seq,int avail_size)1125 static int mptcp_check_allowed_size(const struct mptcp_sock *msk, struct sock *ssk,
1126 u64 data_seq, int avail_size)
1127 {
1128 u64 window_end = mptcp_wnd_end(msk);
1129 u64 mptcp_snd_wnd;
1130
1131 if (__mptcp_check_fallback(msk))
1132 return avail_size;
1133
1134 mptcp_snd_wnd = window_end - data_seq;
1135 avail_size = min_t(unsigned int, mptcp_snd_wnd, avail_size);
1136
1137 if (unlikely(tcp_sk(ssk)->snd_wnd < mptcp_snd_wnd)) {
1138 tcp_sk(ssk)->snd_wnd = min_t(u64, U32_MAX, mptcp_snd_wnd);
1139 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_SNDWNDSHARED);
1140 }
1141
1142 return avail_size;
1143 }
1144
__mptcp_add_ext(struct sk_buff * skb,gfp_t gfp)1145 static bool __mptcp_add_ext(struct sk_buff *skb, gfp_t gfp)
1146 {
1147 struct skb_ext *mpext = __skb_ext_alloc(gfp);
1148
1149 if (!mpext)
1150 return false;
1151 __skb_ext_set(skb, SKB_EXT_MPTCP, mpext);
1152 return true;
1153 }
1154
__mptcp_do_alloc_tx_skb(struct sock * sk,gfp_t gfp)1155 static struct sk_buff *__mptcp_do_alloc_tx_skb(struct sock *sk, gfp_t gfp)
1156 {
1157 struct sk_buff *skb;
1158
1159 skb = alloc_skb_fclone(MAX_TCP_HEADER, gfp);
1160 if (likely(skb)) {
1161 if (likely(__mptcp_add_ext(skb, gfp))) {
1162 skb_reserve(skb, MAX_TCP_HEADER);
1163 skb->ip_summed = CHECKSUM_PARTIAL;
1164 INIT_LIST_HEAD(&skb->tcp_tsorted_anchor);
1165 return skb;
1166 }
1167 __kfree_skb(skb);
1168 } else {
1169 mptcp_enter_memory_pressure(sk);
1170 }
1171 return NULL;
1172 }
1173
__mptcp_alloc_tx_skb(struct sock * sk,struct sock * ssk,gfp_t gfp)1174 static struct sk_buff *__mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, gfp_t gfp)
1175 {
1176 struct sk_buff *skb;
1177
1178 skb = __mptcp_do_alloc_tx_skb(sk, gfp);
1179 if (!skb)
1180 return NULL;
1181
1182 if (likely(sk_wmem_schedule(ssk, skb->truesize))) {
1183 tcp_skb_entail(ssk, skb);
1184 return skb;
1185 }
1186 tcp_skb_tsorted_anchor_cleanup(skb);
1187 kfree_skb(skb);
1188 return NULL;
1189 }
1190
mptcp_alloc_tx_skb(struct sock * sk,struct sock * ssk,bool data_lock_held)1191 static struct sk_buff *mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, bool data_lock_held)
1192 {
1193 gfp_t gfp = data_lock_held ? GFP_ATOMIC : sk->sk_allocation;
1194
1195 return __mptcp_alloc_tx_skb(sk, ssk, gfp);
1196 }
1197
1198 /* note: this always recompute the csum on the whole skb, even
1199 * if we just appended a single frag. More status info needed
1200 */
mptcp_update_data_checksum(struct sk_buff * skb,int added)1201 static void mptcp_update_data_checksum(struct sk_buff *skb, int added)
1202 {
1203 struct mptcp_ext *mpext = mptcp_get_ext(skb);
1204 __wsum csum = ~csum_unfold(mpext->csum);
1205 int offset = skb->len - added;
1206
1207 mpext->csum = csum_fold(csum_block_add(csum, skb_checksum(skb, offset, added, 0), offset));
1208 }
1209
mptcp_update_infinite_map(struct mptcp_sock * msk,struct sock * ssk,struct mptcp_ext * mpext)1210 static void mptcp_update_infinite_map(struct mptcp_sock *msk,
1211 struct sock *ssk,
1212 struct mptcp_ext *mpext)
1213 {
1214 if (!mpext)
1215 return;
1216
1217 mpext->infinite_map = 1;
1218 mpext->data_len = 0;
1219
1220 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPTX);
1221 mptcp_subflow_ctx(ssk)->send_infinite_map = 0;
1222 pr_fallback(msk);
1223 mptcp_do_fallback(ssk);
1224 }
1225
1226 #define MPTCP_MAX_GSO_SIZE (GSO_LEGACY_MAX_SIZE - (MAX_TCP_HEADER + 1))
1227
mptcp_sendmsg_frag(struct sock * sk,struct sock * ssk,struct mptcp_data_frag * dfrag,struct mptcp_sendmsg_info * info)1228 static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
1229 struct mptcp_data_frag *dfrag,
1230 struct mptcp_sendmsg_info *info)
1231 {
1232 u64 data_seq = dfrag->data_seq + info->sent;
1233 int offset = dfrag->offset + info->sent;
1234 struct mptcp_sock *msk = mptcp_sk(sk);
1235 bool zero_window_probe = false;
1236 struct mptcp_ext *mpext = NULL;
1237 bool can_coalesce = false;
1238 bool reuse_skb = true;
1239 struct sk_buff *skb;
1240 size_t copy;
1241 int i;
1242
1243 pr_debug("msk=%p ssk=%p sending dfrag at seq=%llu len=%u already sent=%u\n",
1244 msk, ssk, dfrag->data_seq, dfrag->data_len, info->sent);
1245
1246 if (WARN_ON_ONCE(info->sent > info->limit ||
1247 info->limit > dfrag->data_len))
1248 return 0;
1249
1250 if (unlikely(!__tcp_can_send(ssk)))
1251 return -EAGAIN;
1252
1253 /* compute send limit */
1254 if (unlikely(ssk->sk_gso_max_size > MPTCP_MAX_GSO_SIZE))
1255 ssk->sk_gso_max_size = MPTCP_MAX_GSO_SIZE;
1256 info->mss_now = tcp_send_mss(ssk, &info->size_goal, info->flags);
1257 copy = info->size_goal;
1258
1259 skb = tcp_write_queue_tail(ssk);
1260 if (skb && copy > skb->len) {
1261 /* Limit the write to the size available in the
1262 * current skb, if any, so that we create at most a new skb.
1263 * Explicitly tells TCP internals to avoid collapsing on later
1264 * queue management operation, to avoid breaking the ext <->
1265 * SSN association set here
1266 */
1267 mpext = mptcp_get_ext(skb);
1268 if (!mptcp_skb_can_collapse_to(data_seq, skb, mpext)) {
1269 TCP_SKB_CB(skb)->eor = 1;
1270 tcp_mark_push(tcp_sk(ssk), skb);
1271 goto alloc_skb;
1272 }
1273
1274 i = skb_shinfo(skb)->nr_frags;
1275 can_coalesce = skb_can_coalesce(skb, i, dfrag->page, offset);
1276 if (!can_coalesce && i >= READ_ONCE(net_hotdata.sysctl_max_skb_frags)) {
1277 tcp_mark_push(tcp_sk(ssk), skb);
1278 goto alloc_skb;
1279 }
1280
1281 copy -= skb->len;
1282 } else {
1283 alloc_skb:
1284 skb = mptcp_alloc_tx_skb(sk, ssk, info->data_lock_held);
1285 if (!skb)
1286 return -ENOMEM;
1287
1288 i = skb_shinfo(skb)->nr_frags;
1289 reuse_skb = false;
1290 mpext = mptcp_get_ext(skb);
1291 }
1292
1293 /* Zero window and all data acked? Probe. */
1294 copy = mptcp_check_allowed_size(msk, ssk, data_seq, copy);
1295 if (copy == 0) {
1296 u64 snd_una = READ_ONCE(msk->snd_una);
1297
1298 if (snd_una != msk->snd_nxt || tcp_write_queue_tail(ssk)) {
1299 tcp_remove_empty_skb(ssk);
1300 return 0;
1301 }
1302
1303 zero_window_probe = true;
1304 data_seq = snd_una - 1;
1305 copy = 1;
1306 }
1307
1308 copy = min_t(size_t, copy, info->limit - info->sent);
1309 if (!sk_wmem_schedule(ssk, copy)) {
1310 tcp_remove_empty_skb(ssk);
1311 return -ENOMEM;
1312 }
1313
1314 if (can_coalesce) {
1315 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1316 } else {
1317 get_page(dfrag->page);
1318 skb_fill_page_desc(skb, i, dfrag->page, offset, copy);
1319 }
1320
1321 skb->len += copy;
1322 skb->data_len += copy;
1323 skb->truesize += copy;
1324 sk_wmem_queued_add(ssk, copy);
1325 sk_mem_charge(ssk, copy);
1326 WRITE_ONCE(tcp_sk(ssk)->write_seq, tcp_sk(ssk)->write_seq + copy);
1327 TCP_SKB_CB(skb)->end_seq += copy;
1328 tcp_skb_pcount_set(skb, 0);
1329
1330 /* on skb reuse we just need to update the DSS len */
1331 if (reuse_skb) {
1332 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1333 mpext->data_len += copy;
1334 goto out;
1335 }
1336
1337 memset(mpext, 0, sizeof(*mpext));
1338 mpext->data_seq = data_seq;
1339 mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq;
1340 mpext->data_len = copy;
1341 mpext->use_map = 1;
1342 mpext->dsn64 = 1;
1343
1344 pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d\n",
1345 mpext->data_seq, mpext->subflow_seq, mpext->data_len,
1346 mpext->dsn64);
1347
1348 if (zero_window_probe) {
1349 mptcp_subflow_ctx(ssk)->rel_write_seq += copy;
1350 mpext->frozen = 1;
1351 if (READ_ONCE(msk->csum_enabled))
1352 mptcp_update_data_checksum(skb, copy);
1353 tcp_push_pending_frames(ssk);
1354 return 0;
1355 }
1356 out:
1357 if (READ_ONCE(msk->csum_enabled))
1358 mptcp_update_data_checksum(skb, copy);
1359 if (mptcp_subflow_ctx(ssk)->send_infinite_map)
1360 mptcp_update_infinite_map(msk, ssk, mpext);
1361 trace_mptcp_sendmsg_frag(mpext);
1362 mptcp_subflow_ctx(ssk)->rel_write_seq += copy;
1363 return copy;
1364 }
1365
1366 #define MPTCP_SEND_BURST_SIZE ((1 << 16) - \
1367 sizeof(struct tcphdr) - \
1368 MAX_TCP_OPTION_SPACE - \
1369 sizeof(struct ipv6hdr) - \
1370 sizeof(struct frag_hdr))
1371
1372 struct subflow_send_info {
1373 struct sock *ssk;
1374 u64 linger_time;
1375 };
1376
mptcp_subflow_set_active(struct mptcp_subflow_context * subflow)1377 void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow)
1378 {
1379 if (!subflow->stale)
1380 return;
1381
1382 subflow->stale = 0;
1383 MPTCP_INC_STATS(sock_net(mptcp_subflow_tcp_sock(subflow)), MPTCP_MIB_SUBFLOWRECOVER);
1384 }
1385
mptcp_subflow_active(struct mptcp_subflow_context * subflow)1386 bool mptcp_subflow_active(struct mptcp_subflow_context *subflow)
1387 {
1388 if (unlikely(subflow->stale)) {
1389 u32 rcv_tstamp = READ_ONCE(tcp_sk(mptcp_subflow_tcp_sock(subflow))->rcv_tstamp);
1390
1391 if (subflow->stale_rcv_tstamp == rcv_tstamp)
1392 return false;
1393
1394 mptcp_subflow_set_active(subflow);
1395 }
1396 return __mptcp_subflow_active(subflow);
1397 }
1398
1399 #define SSK_MODE_ACTIVE 0
1400 #define SSK_MODE_BACKUP 1
1401 #define SSK_MODE_MAX 2
1402
1403 /* implement the mptcp packet scheduler;
1404 * returns the subflow that will transmit the next DSS
1405 * additionally updates the rtx timeout
1406 */
mptcp_subflow_get_send(struct mptcp_sock * msk)1407 struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk)
1408 {
1409 struct subflow_send_info send_info[SSK_MODE_MAX];
1410 struct mptcp_subflow_context *subflow;
1411 struct sock *sk = (struct sock *)msk;
1412 u32 pace, burst, wmem;
1413 int i, nr_active = 0;
1414 struct sock *ssk;
1415 u64 linger_time;
1416 long tout = 0;
1417
1418 /* pick the subflow with the lower wmem/wspace ratio */
1419 for (i = 0; i < SSK_MODE_MAX; ++i) {
1420 send_info[i].ssk = NULL;
1421 send_info[i].linger_time = -1;
1422 }
1423
1424 mptcp_for_each_subflow(msk, subflow) {
1425 bool backup = subflow->backup || subflow->request_bkup;
1426
1427 trace_mptcp_subflow_get_send(subflow);
1428 ssk = mptcp_subflow_tcp_sock(subflow);
1429 if (!mptcp_subflow_active(subflow))
1430 continue;
1431
1432 tout = max(tout, mptcp_timeout_from_subflow(subflow));
1433 nr_active += !backup;
1434 pace = subflow->avg_pacing_rate;
1435 if (unlikely(!pace)) {
1436 /* init pacing rate from socket */
1437 subflow->avg_pacing_rate = READ_ONCE(ssk->sk_pacing_rate);
1438 pace = subflow->avg_pacing_rate;
1439 if (!pace)
1440 continue;
1441 }
1442
1443 linger_time = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32, pace);
1444 if (linger_time < send_info[backup].linger_time) {
1445 send_info[backup].ssk = ssk;
1446 send_info[backup].linger_time = linger_time;
1447 }
1448 }
1449 __mptcp_set_timeout(sk, tout);
1450
1451 /* pick the best backup if no other subflow is active */
1452 if (!nr_active)
1453 send_info[SSK_MODE_ACTIVE].ssk = send_info[SSK_MODE_BACKUP].ssk;
1454
1455 /* According to the blest algorithm, to avoid HoL blocking for the
1456 * faster flow, we need to:
1457 * - estimate the faster flow linger time
1458 * - use the above to estimate the amount of byte transferred
1459 * by the faster flow
1460 * - check that the amount of queued data is greter than the above,
1461 * otherwise do not use the picked, slower, subflow
1462 * We select the subflow with the shorter estimated time to flush
1463 * the queued mem, which basically ensure the above. We just need
1464 * to check that subflow has a non empty cwin.
1465 */
1466 ssk = send_info[SSK_MODE_ACTIVE].ssk;
1467 if (!ssk || !sk_stream_memory_free(ssk))
1468 return NULL;
1469
1470 burst = min_t(int, MPTCP_SEND_BURST_SIZE, mptcp_wnd_end(msk) - msk->snd_nxt);
1471 wmem = READ_ONCE(ssk->sk_wmem_queued);
1472 if (!burst)
1473 return ssk;
1474
1475 subflow = mptcp_subflow_ctx(ssk);
1476 subflow->avg_pacing_rate = div_u64((u64)subflow->avg_pacing_rate * wmem +
1477 READ_ONCE(ssk->sk_pacing_rate) * burst,
1478 burst + wmem);
1479 msk->snd_burst = burst;
1480 return ssk;
1481 }
1482
mptcp_push_release(struct sock * ssk,struct mptcp_sendmsg_info * info)1483 static void mptcp_push_release(struct sock *ssk, struct mptcp_sendmsg_info *info)
1484 {
1485 tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal);
1486 release_sock(ssk);
1487 }
1488
mptcp_update_post_push(struct mptcp_sock * msk,struct mptcp_data_frag * dfrag,u32 sent)1489 static void mptcp_update_post_push(struct mptcp_sock *msk,
1490 struct mptcp_data_frag *dfrag,
1491 u32 sent)
1492 {
1493 u64 snd_nxt_new = dfrag->data_seq;
1494
1495 dfrag->already_sent += sent;
1496
1497 msk->snd_burst -= sent;
1498
1499 snd_nxt_new += dfrag->already_sent;
1500
1501 /* snd_nxt_new can be smaller than snd_nxt in case mptcp
1502 * is recovering after a failover. In that event, this re-sends
1503 * old segments.
1504 *
1505 * Thus compute snd_nxt_new candidate based on
1506 * the dfrag->data_seq that was sent and the data
1507 * that has been handed to the subflow for transmission
1508 * and skip update in case it was old dfrag.
1509 */
1510 if (likely(after64(snd_nxt_new, msk->snd_nxt))) {
1511 msk->bytes_sent += snd_nxt_new - msk->snd_nxt;
1512 WRITE_ONCE(msk->snd_nxt, snd_nxt_new);
1513 }
1514 }
1515
mptcp_check_and_set_pending(struct sock * sk)1516 void mptcp_check_and_set_pending(struct sock *sk)
1517 {
1518 if (mptcp_send_head(sk)) {
1519 mptcp_data_lock(sk);
1520 mptcp_sk(sk)->cb_flags |= BIT(MPTCP_PUSH_PENDING);
1521 mptcp_data_unlock(sk);
1522 }
1523 }
1524
__subflow_push_pending(struct sock * sk,struct sock * ssk,struct mptcp_sendmsg_info * info)1525 static int __subflow_push_pending(struct sock *sk, struct sock *ssk,
1526 struct mptcp_sendmsg_info *info)
1527 {
1528 struct mptcp_sock *msk = mptcp_sk(sk);
1529 struct mptcp_data_frag *dfrag;
1530 int len, copied = 0, err = 0;
1531
1532 while ((dfrag = mptcp_send_head(sk))) {
1533 info->sent = dfrag->already_sent;
1534 info->limit = dfrag->data_len;
1535 len = dfrag->data_len - dfrag->already_sent;
1536 while (len > 0) {
1537 int ret = 0;
1538
1539 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, info);
1540 if (ret <= 0) {
1541 err = copied ? : ret;
1542 goto out;
1543 }
1544
1545 info->sent += ret;
1546 copied += ret;
1547 len -= ret;
1548
1549 mptcp_update_post_push(msk, dfrag, ret);
1550 }
1551 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1552
1553 if (msk->snd_burst <= 0 ||
1554 !sk_stream_memory_free(ssk) ||
1555 !mptcp_subflow_active(mptcp_subflow_ctx(ssk))) {
1556 err = copied;
1557 goto out;
1558 }
1559 mptcp_set_timeout(sk);
1560 }
1561 err = copied;
1562
1563 out:
1564 if (err > 0)
1565 msk->last_data_sent = tcp_jiffies32;
1566 return err;
1567 }
1568
__mptcp_push_pending(struct sock * sk,unsigned int flags)1569 void __mptcp_push_pending(struct sock *sk, unsigned int flags)
1570 {
1571 struct sock *prev_ssk = NULL, *ssk = NULL;
1572 struct mptcp_sock *msk = mptcp_sk(sk);
1573 struct mptcp_sendmsg_info info = {
1574 .flags = flags,
1575 };
1576 bool do_check_data_fin = false;
1577 int push_count = 1;
1578
1579 while (mptcp_send_head(sk) && (push_count > 0)) {
1580 struct mptcp_subflow_context *subflow;
1581 int ret = 0;
1582
1583 if (mptcp_sched_get_send(msk))
1584 break;
1585
1586 push_count = 0;
1587
1588 mptcp_for_each_subflow(msk, subflow) {
1589 if (READ_ONCE(subflow->scheduled)) {
1590 mptcp_subflow_set_scheduled(subflow, false);
1591
1592 prev_ssk = ssk;
1593 ssk = mptcp_subflow_tcp_sock(subflow);
1594 if (ssk != prev_ssk) {
1595 /* First check. If the ssk has changed since
1596 * the last round, release prev_ssk
1597 */
1598 if (prev_ssk)
1599 mptcp_push_release(prev_ssk, &info);
1600
1601 /* Need to lock the new subflow only if different
1602 * from the previous one, otherwise we are still
1603 * helding the relevant lock
1604 */
1605 lock_sock(ssk);
1606 }
1607
1608 push_count++;
1609
1610 ret = __subflow_push_pending(sk, ssk, &info);
1611 if (ret <= 0) {
1612 if (ret != -EAGAIN ||
1613 (1 << ssk->sk_state) &
1614 (TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSE))
1615 push_count--;
1616 continue;
1617 }
1618 do_check_data_fin = true;
1619 }
1620 }
1621 }
1622
1623 /* at this point we held the socket lock for the last subflow we used */
1624 if (ssk)
1625 mptcp_push_release(ssk, &info);
1626
1627 /* ensure the rtx timer is running */
1628 if (!mptcp_rtx_timer_pending(sk))
1629 mptcp_reset_rtx_timer(sk);
1630 if (do_check_data_fin)
1631 mptcp_check_send_data_fin(sk);
1632 }
1633
__mptcp_subflow_push_pending(struct sock * sk,struct sock * ssk,bool first)1634 static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk, bool first)
1635 {
1636 struct mptcp_sock *msk = mptcp_sk(sk);
1637 struct mptcp_sendmsg_info info = {
1638 .data_lock_held = true,
1639 };
1640 bool keep_pushing = true;
1641 struct sock *xmit_ssk;
1642 int copied = 0;
1643
1644 info.flags = 0;
1645 while (mptcp_send_head(sk) && keep_pushing) {
1646 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1647 int ret = 0;
1648
1649 /* check for a different subflow usage only after
1650 * spooling the first chunk of data
1651 */
1652 if (first) {
1653 mptcp_subflow_set_scheduled(subflow, false);
1654 ret = __subflow_push_pending(sk, ssk, &info);
1655 first = false;
1656 if (ret <= 0)
1657 break;
1658 copied += ret;
1659 continue;
1660 }
1661
1662 if (mptcp_sched_get_send(msk))
1663 goto out;
1664
1665 if (READ_ONCE(subflow->scheduled)) {
1666 mptcp_subflow_set_scheduled(subflow, false);
1667 ret = __subflow_push_pending(sk, ssk, &info);
1668 if (ret <= 0)
1669 keep_pushing = false;
1670 copied += ret;
1671 }
1672
1673 mptcp_for_each_subflow(msk, subflow) {
1674 if (READ_ONCE(subflow->scheduled)) {
1675 xmit_ssk = mptcp_subflow_tcp_sock(subflow);
1676 if (xmit_ssk != ssk) {
1677 mptcp_subflow_delegate(subflow,
1678 MPTCP_DELEGATE_SEND);
1679 keep_pushing = false;
1680 }
1681 }
1682 }
1683 }
1684
1685 out:
1686 /* __mptcp_alloc_tx_skb could have released some wmem and we are
1687 * not going to flush it via release_sock()
1688 */
1689 if (copied) {
1690 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
1691 info.size_goal);
1692 if (!mptcp_rtx_timer_pending(sk))
1693 mptcp_reset_rtx_timer(sk);
1694
1695 if (msk->snd_data_fin_enable &&
1696 msk->snd_nxt + 1 == msk->write_seq)
1697 mptcp_schedule_work(sk);
1698 }
1699 }
1700
1701 static int mptcp_disconnect(struct sock *sk, int flags);
1702
mptcp_sendmsg_fastopen(struct sock * sk,struct msghdr * msg,size_t len,int * copied_syn)1703 static int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
1704 size_t len, int *copied_syn)
1705 {
1706 unsigned int saved_flags = msg->msg_flags;
1707 struct mptcp_sock *msk = mptcp_sk(sk);
1708 struct sock *ssk;
1709 int ret;
1710
1711 /* on flags based fastopen the mptcp is supposed to create the
1712 * first subflow right now. Otherwise we are in the defer_connect
1713 * path, and the first subflow must be already present.
1714 * Since the defer_connect flag is cleared after the first succsful
1715 * fastopen attempt, no need to check for additional subflow status.
1716 */
1717 if (msg->msg_flags & MSG_FASTOPEN) {
1718 ssk = __mptcp_nmpc_sk(msk);
1719 if (IS_ERR(ssk))
1720 return PTR_ERR(ssk);
1721 }
1722 if (!msk->first)
1723 return -EINVAL;
1724
1725 ssk = msk->first;
1726
1727 lock_sock(ssk);
1728 msg->msg_flags |= MSG_DONTWAIT;
1729 msk->fastopening = 1;
1730 ret = tcp_sendmsg_fastopen(ssk, msg, copied_syn, len, NULL);
1731 msk->fastopening = 0;
1732 msg->msg_flags = saved_flags;
1733 release_sock(ssk);
1734
1735 /* do the blocking bits of inet_stream_connect outside the ssk socket lock */
1736 if (ret == -EINPROGRESS && !(msg->msg_flags & MSG_DONTWAIT)) {
1737 ret = __inet_stream_connect(sk->sk_socket, msg->msg_name,
1738 msg->msg_namelen, msg->msg_flags, 1);
1739
1740 /* Keep the same behaviour of plain TCP: zero the copied bytes in
1741 * case of any error, except timeout or signal
1742 */
1743 if (ret && ret != -EINPROGRESS && ret != -ERESTARTSYS && ret != -EINTR)
1744 *copied_syn = 0;
1745 } else if (ret && ret != -EINPROGRESS) {
1746 /* The disconnect() op called by tcp_sendmsg_fastopen()/
1747 * __inet_stream_connect() can fail, due to looking check,
1748 * see mptcp_disconnect().
1749 * Attempt it again outside the problematic scope.
1750 */
1751 if (!mptcp_disconnect(sk, 0))
1752 sk->sk_socket->state = SS_UNCONNECTED;
1753 }
1754 inet_clear_bit(DEFER_CONNECT, sk);
1755
1756 return ret;
1757 }
1758
do_copy_data_nocache(struct sock * sk,int copy,struct iov_iter * from,char * to)1759 static int do_copy_data_nocache(struct sock *sk, int copy,
1760 struct iov_iter *from, char *to)
1761 {
1762 if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) {
1763 if (!copy_from_iter_full_nocache(to, copy, from))
1764 return -EFAULT;
1765 } else if (!copy_from_iter_full(to, copy, from)) {
1766 return -EFAULT;
1767 }
1768 return 0;
1769 }
1770
1771 /* open-code sk_stream_memory_free() plus sent limit computation to
1772 * avoid indirect calls in fast-path.
1773 * Called under the msk socket lock, so we can avoid a bunch of ONCE
1774 * annotations.
1775 */
mptcp_send_limit(const struct sock * sk)1776 static u32 mptcp_send_limit(const struct sock *sk)
1777 {
1778 const struct mptcp_sock *msk = mptcp_sk(sk);
1779 u32 limit, not_sent;
1780
1781 if (sk->sk_wmem_queued >= READ_ONCE(sk->sk_sndbuf))
1782 return 0;
1783
1784 limit = mptcp_notsent_lowat(sk);
1785 if (limit == UINT_MAX)
1786 return UINT_MAX;
1787
1788 not_sent = msk->write_seq - msk->snd_nxt;
1789 if (not_sent >= limit)
1790 return 0;
1791
1792 return limit - not_sent;
1793 }
1794
mptcp_sendmsg(struct sock * sk,struct msghdr * msg,size_t len)1795 static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
1796 {
1797 struct mptcp_sock *msk = mptcp_sk(sk);
1798 struct page_frag *pfrag;
1799 size_t copied = 0;
1800 int ret = 0;
1801 long timeo;
1802
1803 /* silently ignore everything else */
1804 msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | MSG_FASTOPEN;
1805
1806 lock_sock(sk);
1807
1808 if (unlikely(inet_test_bit(DEFER_CONNECT, sk) ||
1809 msg->msg_flags & MSG_FASTOPEN)) {
1810 int copied_syn = 0;
1811
1812 ret = mptcp_sendmsg_fastopen(sk, msg, len, &copied_syn);
1813 copied += copied_syn;
1814 if (ret == -EINPROGRESS && copied_syn > 0)
1815 goto out;
1816 else if (ret)
1817 goto do_error;
1818 }
1819
1820 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1821
1822 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
1823 ret = sk_stream_wait_connect(sk, &timeo);
1824 if (ret)
1825 goto do_error;
1826 }
1827
1828 ret = -EPIPE;
1829 if (unlikely(sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)))
1830 goto do_error;
1831
1832 pfrag = sk_page_frag(sk);
1833
1834 while (msg_data_left(msg)) {
1835 int total_ts, frag_truesize = 0;
1836 struct mptcp_data_frag *dfrag;
1837 bool dfrag_collapsed;
1838 size_t psize, offset;
1839 u32 copy_limit;
1840
1841 /* ensure fitting the notsent_lowat() constraint */
1842 copy_limit = mptcp_send_limit(sk);
1843 if (!copy_limit)
1844 goto wait_for_memory;
1845
1846 /* reuse tail pfrag, if possible, or carve a new one from the
1847 * page allocator
1848 */
1849 dfrag = mptcp_pending_tail(sk);
1850 dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag);
1851 if (!dfrag_collapsed) {
1852 if (!mptcp_page_frag_refill(sk, pfrag))
1853 goto wait_for_memory;
1854
1855 dfrag = mptcp_carve_data_frag(msk, pfrag, pfrag->offset);
1856 frag_truesize = dfrag->overhead;
1857 }
1858
1859 /* we do not bound vs wspace, to allow a single packet.
1860 * memory accounting will prevent execessive memory usage
1861 * anyway
1862 */
1863 offset = dfrag->offset + dfrag->data_len;
1864 psize = pfrag->size - offset;
1865 psize = min_t(size_t, psize, msg_data_left(msg));
1866 psize = min_t(size_t, psize, copy_limit);
1867 total_ts = psize + frag_truesize;
1868
1869 if (!sk_wmem_schedule(sk, total_ts))
1870 goto wait_for_memory;
1871
1872 ret = do_copy_data_nocache(sk, psize, &msg->msg_iter,
1873 page_address(dfrag->page) + offset);
1874 if (ret)
1875 goto do_error;
1876
1877 /* data successfully copied into the write queue */
1878 sk_forward_alloc_add(sk, -total_ts);
1879 copied += psize;
1880 dfrag->data_len += psize;
1881 frag_truesize += psize;
1882 pfrag->offset += frag_truesize;
1883 WRITE_ONCE(msk->write_seq, msk->write_seq + psize);
1884
1885 /* charge data on mptcp pending queue to the msk socket
1886 * Note: we charge such data both to sk and ssk
1887 */
1888 sk_wmem_queued_add(sk, frag_truesize);
1889 if (!dfrag_collapsed) {
1890 get_page(dfrag->page);
1891 list_add_tail(&dfrag->list, &msk->rtx_queue);
1892 if (!msk->first_pending)
1893 WRITE_ONCE(msk->first_pending, dfrag);
1894 }
1895 pr_debug("msk=%p dfrag at seq=%llu len=%u sent=%u new=%d\n", msk,
1896 dfrag->data_seq, dfrag->data_len, dfrag->already_sent,
1897 !dfrag_collapsed);
1898
1899 continue;
1900
1901 wait_for_memory:
1902 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1903 __mptcp_push_pending(sk, msg->msg_flags);
1904 ret = sk_stream_wait_memory(sk, &timeo);
1905 if (ret)
1906 goto do_error;
1907 }
1908
1909 if (copied)
1910 __mptcp_push_pending(sk, msg->msg_flags);
1911
1912 out:
1913 release_sock(sk);
1914 return copied;
1915
1916 do_error:
1917 if (copied)
1918 goto out;
1919
1920 copied = sk_stream_error(sk, msg->msg_flags, ret);
1921 goto out;
1922 }
1923
__mptcp_recvmsg_mskq(struct mptcp_sock * msk,struct msghdr * msg,size_t len,int flags,struct scm_timestamping_internal * tss,int * cmsg_flags)1924 static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk,
1925 struct msghdr *msg,
1926 size_t len, int flags,
1927 struct scm_timestamping_internal *tss,
1928 int *cmsg_flags)
1929 {
1930 struct sk_buff *skb, *tmp;
1931 int copied = 0;
1932
1933 skb_queue_walk_safe(&msk->receive_queue, skb, tmp) {
1934 u32 offset = MPTCP_SKB_CB(skb)->offset;
1935 u32 data_len = skb->len - offset;
1936 u32 count = min_t(size_t, len - copied, data_len);
1937 int err;
1938
1939 if (!(flags & MSG_TRUNC)) {
1940 err = skb_copy_datagram_msg(skb, offset, msg, count);
1941 if (unlikely(err < 0)) {
1942 if (!copied)
1943 return err;
1944 break;
1945 }
1946 }
1947
1948 if (MPTCP_SKB_CB(skb)->has_rxtstamp) {
1949 tcp_update_recv_tstamps(skb, tss);
1950 *cmsg_flags |= MPTCP_CMSG_TS;
1951 }
1952
1953 copied += count;
1954
1955 if (count < data_len) {
1956 if (!(flags & MSG_PEEK)) {
1957 MPTCP_SKB_CB(skb)->offset += count;
1958 MPTCP_SKB_CB(skb)->map_seq += count;
1959 msk->bytes_consumed += count;
1960 }
1961 break;
1962 }
1963
1964 if (!(flags & MSG_PEEK)) {
1965 /* we will bulk release the skb memory later */
1966 skb->destructor = NULL;
1967 WRITE_ONCE(msk->rmem_released, msk->rmem_released + skb->truesize);
1968 __skb_unlink(skb, &msk->receive_queue);
1969 __kfree_skb(skb);
1970 msk->bytes_consumed += count;
1971 }
1972
1973 if (copied >= len)
1974 break;
1975 }
1976
1977 return copied;
1978 }
1979
1980 /* receive buffer autotuning. See tcp_rcv_space_adjust for more information.
1981 *
1982 * Only difference: Use highest rtt estimate of the subflows in use.
1983 */
mptcp_rcv_space_adjust(struct mptcp_sock * msk,int copied)1984 static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied)
1985 {
1986 struct mptcp_subflow_context *subflow;
1987 struct sock *sk = (struct sock *)msk;
1988 u8 scaling_ratio = U8_MAX;
1989 u32 time, advmss = 1;
1990 u64 rtt_us, mstamp;
1991
1992 msk_owned_by_me(msk);
1993
1994 if (copied <= 0)
1995 return;
1996
1997 if (!msk->rcvspace_init)
1998 mptcp_rcv_space_init(msk, msk->first);
1999
2000 msk->rcvq_space.copied += copied;
2001
2002 mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC);
2003 time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time);
2004
2005 rtt_us = msk->rcvq_space.rtt_us;
2006 if (rtt_us && time < (rtt_us >> 3))
2007 return;
2008
2009 rtt_us = 0;
2010 mptcp_for_each_subflow(msk, subflow) {
2011 const struct tcp_sock *tp;
2012 u64 sf_rtt_us;
2013 u32 sf_advmss;
2014
2015 tp = tcp_sk(mptcp_subflow_tcp_sock(subflow));
2016
2017 sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us);
2018 sf_advmss = READ_ONCE(tp->advmss);
2019
2020 rtt_us = max(sf_rtt_us, rtt_us);
2021 advmss = max(sf_advmss, advmss);
2022 scaling_ratio = min(tp->scaling_ratio, scaling_ratio);
2023 }
2024
2025 msk->rcvq_space.rtt_us = rtt_us;
2026 msk->scaling_ratio = scaling_ratio;
2027 if (time < (rtt_us >> 3) || rtt_us == 0)
2028 return;
2029
2030 if (msk->rcvq_space.copied <= msk->rcvq_space.space)
2031 goto new_measure;
2032
2033 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf) &&
2034 !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
2035 u64 rcvwin, grow;
2036 int rcvbuf;
2037
2038 rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss;
2039
2040 grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space);
2041
2042 do_div(grow, msk->rcvq_space.space);
2043 rcvwin += (grow << 1);
2044
2045 rcvbuf = min_t(u64, mptcp_space_from_win(sk, rcvwin),
2046 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[2]));
2047
2048 if (rcvbuf > sk->sk_rcvbuf) {
2049 u32 window_clamp;
2050
2051 window_clamp = mptcp_win_from_space(sk, rcvbuf);
2052 WRITE_ONCE(sk->sk_rcvbuf, rcvbuf);
2053
2054 /* Make subflows follow along. If we do not do this, we
2055 * get drops at subflow level if skbs can't be moved to
2056 * the mptcp rx queue fast enough (announced rcv_win can
2057 * exceed ssk->sk_rcvbuf).
2058 */
2059 mptcp_for_each_subflow(msk, subflow) {
2060 struct sock *ssk;
2061 bool slow;
2062
2063 ssk = mptcp_subflow_tcp_sock(subflow);
2064 slow = lock_sock_fast(ssk);
2065 WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf);
2066 WRITE_ONCE(tcp_sk(ssk)->window_clamp, window_clamp);
2067 tcp_cleanup_rbuf(ssk, 1);
2068 unlock_sock_fast(ssk, slow);
2069 }
2070 }
2071 }
2072
2073 msk->rcvq_space.space = msk->rcvq_space.copied;
2074 new_measure:
2075 msk->rcvq_space.copied = 0;
2076 msk->rcvq_space.time = mstamp;
2077 }
2078
__mptcp_update_rmem(struct sock * sk)2079 static void __mptcp_update_rmem(struct sock *sk)
2080 {
2081 struct mptcp_sock *msk = mptcp_sk(sk);
2082
2083 if (!msk->rmem_released)
2084 return;
2085
2086 atomic_sub(msk->rmem_released, &sk->sk_rmem_alloc);
2087 mptcp_rmem_uncharge(sk, msk->rmem_released);
2088 WRITE_ONCE(msk->rmem_released, 0);
2089 }
2090
__mptcp_splice_receive_queue(struct sock * sk)2091 static void __mptcp_splice_receive_queue(struct sock *sk)
2092 {
2093 struct mptcp_sock *msk = mptcp_sk(sk);
2094
2095 skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue);
2096 }
2097
__mptcp_move_skbs(struct mptcp_sock * msk)2098 static bool __mptcp_move_skbs(struct mptcp_sock *msk)
2099 {
2100 struct sock *sk = (struct sock *)msk;
2101 unsigned int moved = 0;
2102 bool ret, done;
2103
2104 do {
2105 struct sock *ssk = mptcp_subflow_recv_lookup(msk);
2106 bool slowpath;
2107
2108 /* we can have data pending in the subflows only if the msk
2109 * receive buffer was full at subflow_data_ready() time,
2110 * that is an unlikely slow path.
2111 */
2112 if (likely(!ssk))
2113 break;
2114
2115 slowpath = lock_sock_fast(ssk);
2116 mptcp_data_lock(sk);
2117 __mptcp_update_rmem(sk);
2118 done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
2119 mptcp_data_unlock(sk);
2120
2121 if (unlikely(ssk->sk_err))
2122 __mptcp_error_report(sk);
2123 unlock_sock_fast(ssk, slowpath);
2124 } while (!done);
2125
2126 /* acquire the data lock only if some input data is pending */
2127 ret = moved > 0;
2128 if (!RB_EMPTY_ROOT(&msk->out_of_order_queue) ||
2129 !skb_queue_empty_lockless(&sk->sk_receive_queue)) {
2130 mptcp_data_lock(sk);
2131 __mptcp_update_rmem(sk);
2132 ret |= __mptcp_ofo_queue(msk);
2133 __mptcp_splice_receive_queue(sk);
2134 mptcp_data_unlock(sk);
2135 }
2136 if (ret)
2137 mptcp_check_data_fin((struct sock *)msk);
2138 return !skb_queue_empty(&msk->receive_queue);
2139 }
2140
mptcp_inq_hint(const struct sock * sk)2141 static unsigned int mptcp_inq_hint(const struct sock *sk)
2142 {
2143 const struct mptcp_sock *msk = mptcp_sk(sk);
2144 const struct sk_buff *skb;
2145
2146 skb = skb_peek(&msk->receive_queue);
2147 if (skb) {
2148 u64 hint_val = READ_ONCE(msk->ack_seq) - MPTCP_SKB_CB(skb)->map_seq;
2149
2150 if (hint_val >= INT_MAX)
2151 return INT_MAX;
2152
2153 return (unsigned int)hint_val;
2154 }
2155
2156 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
2157 return 1;
2158
2159 return 0;
2160 }
2161
mptcp_recvmsg(struct sock * sk,struct msghdr * msg,size_t len,int flags,int * addr_len)2162 static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
2163 int flags, int *addr_len)
2164 {
2165 struct mptcp_sock *msk = mptcp_sk(sk);
2166 struct scm_timestamping_internal tss;
2167 int copied = 0, cmsg_flags = 0;
2168 int target;
2169 long timeo;
2170
2171 /* MSG_ERRQUEUE is really a no-op till we support IP_RECVERR */
2172 if (unlikely(flags & MSG_ERRQUEUE))
2173 return inet_recv_error(sk, msg, len, addr_len);
2174
2175 lock_sock(sk);
2176 if (unlikely(sk->sk_state == TCP_LISTEN)) {
2177 copied = -ENOTCONN;
2178 goto out_err;
2179 }
2180
2181 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2182
2183 len = min_t(size_t, len, INT_MAX);
2184 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
2185
2186 if (unlikely(msk->recvmsg_inq))
2187 cmsg_flags = MPTCP_CMSG_INQ;
2188
2189 while (copied < len) {
2190 int bytes_read;
2191
2192 bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags, &tss, &cmsg_flags);
2193 if (unlikely(bytes_read < 0)) {
2194 if (!copied)
2195 copied = bytes_read;
2196 goto out_err;
2197 }
2198
2199 copied += bytes_read;
2200
2201 /* be sure to advertise window change */
2202 mptcp_cleanup_rbuf(msk);
2203
2204 if (skb_queue_empty(&msk->receive_queue) && __mptcp_move_skbs(msk))
2205 continue;
2206
2207 /* only the MPTCP socket status is relevant here. The exit
2208 * conditions mirror closely tcp_recvmsg()
2209 */
2210 if (copied >= target)
2211 break;
2212
2213 if (copied) {
2214 if (sk->sk_err ||
2215 sk->sk_state == TCP_CLOSE ||
2216 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2217 !timeo ||
2218 signal_pending(current))
2219 break;
2220 } else {
2221 if (sk->sk_err) {
2222 copied = sock_error(sk);
2223 break;
2224 }
2225
2226 if (sk->sk_shutdown & RCV_SHUTDOWN) {
2227 /* race breaker: the shutdown could be after the
2228 * previous receive queue check
2229 */
2230 if (__mptcp_move_skbs(msk))
2231 continue;
2232 break;
2233 }
2234
2235 if (sk->sk_state == TCP_CLOSE) {
2236 copied = -ENOTCONN;
2237 break;
2238 }
2239
2240 if (!timeo) {
2241 copied = -EAGAIN;
2242 break;
2243 }
2244
2245 if (signal_pending(current)) {
2246 copied = sock_intr_errno(timeo);
2247 break;
2248 }
2249 }
2250
2251 pr_debug("block timeout %ld\n", timeo);
2252 sk_wait_data(sk, &timeo, NULL);
2253 }
2254
2255 out_err:
2256 if (cmsg_flags && copied >= 0) {
2257 if (cmsg_flags & MPTCP_CMSG_TS)
2258 tcp_recv_timestamp(msg, sk, &tss);
2259
2260 if (cmsg_flags & MPTCP_CMSG_INQ) {
2261 unsigned int inq = mptcp_inq_hint(sk);
2262
2263 put_cmsg(msg, SOL_TCP, TCP_CM_INQ, sizeof(inq), &inq);
2264 }
2265 }
2266
2267 pr_debug("msk=%p rx queue empty=%d:%d copied=%d\n",
2268 msk, skb_queue_empty_lockless(&sk->sk_receive_queue),
2269 skb_queue_empty(&msk->receive_queue), copied);
2270 if (!(flags & MSG_PEEK))
2271 mptcp_rcv_space_adjust(msk, copied);
2272
2273 release_sock(sk);
2274 return copied;
2275 }
2276
mptcp_retransmit_timer(struct timer_list * t)2277 static void mptcp_retransmit_timer(struct timer_list *t)
2278 {
2279 struct inet_connection_sock *icsk = from_timer(icsk, t,
2280 icsk_retransmit_timer);
2281 struct sock *sk = &icsk->icsk_inet.sk;
2282 struct mptcp_sock *msk = mptcp_sk(sk);
2283
2284 bh_lock_sock(sk);
2285 if (!sock_owned_by_user(sk)) {
2286 /* we need a process context to retransmit */
2287 if (!test_and_set_bit(MPTCP_WORK_RTX, &msk->flags))
2288 mptcp_schedule_work(sk);
2289 } else {
2290 /* delegate our work to tcp_release_cb() */
2291 __set_bit(MPTCP_RETRANSMIT, &msk->cb_flags);
2292 }
2293 bh_unlock_sock(sk);
2294 sock_put(sk);
2295 }
2296
mptcp_tout_timer(struct timer_list * t)2297 static void mptcp_tout_timer(struct timer_list *t)
2298 {
2299 struct sock *sk = from_timer(sk, t, sk_timer);
2300
2301 mptcp_schedule_work(sk);
2302 sock_put(sk);
2303 }
2304
2305 /* Find an idle subflow. Return NULL if there is unacked data at tcp
2306 * level.
2307 *
2308 * A backup subflow is returned only if that is the only kind available.
2309 */
mptcp_subflow_get_retrans(struct mptcp_sock * msk)2310 struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk)
2311 {
2312 struct sock *backup = NULL, *pick = NULL;
2313 struct mptcp_subflow_context *subflow;
2314 int min_stale_count = INT_MAX;
2315
2316 mptcp_for_each_subflow(msk, subflow) {
2317 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2318
2319 if (!__mptcp_subflow_active(subflow))
2320 continue;
2321
2322 /* still data outstanding at TCP level? skip this */
2323 if (!tcp_rtx_and_write_queues_empty(ssk)) {
2324 mptcp_pm_subflow_chk_stale(msk, ssk);
2325 min_stale_count = min_t(int, min_stale_count, subflow->stale_count);
2326 continue;
2327 }
2328
2329 if (subflow->backup || subflow->request_bkup) {
2330 if (!backup)
2331 backup = ssk;
2332 continue;
2333 }
2334
2335 if (!pick)
2336 pick = ssk;
2337 }
2338
2339 if (pick)
2340 return pick;
2341
2342 /* use backup only if there are no progresses anywhere */
2343 return min_stale_count > 1 ? backup : NULL;
2344 }
2345
__mptcp_retransmit_pending_data(struct sock * sk)2346 bool __mptcp_retransmit_pending_data(struct sock *sk)
2347 {
2348 struct mptcp_data_frag *cur, *rtx_head;
2349 struct mptcp_sock *msk = mptcp_sk(sk);
2350
2351 if (__mptcp_check_fallback(msk))
2352 return false;
2353
2354 /* the closing socket has some data untransmitted and/or unacked:
2355 * some data in the mptcp rtx queue has not really xmitted yet.
2356 * keep it simple and re-inject the whole mptcp level rtx queue
2357 */
2358 mptcp_data_lock(sk);
2359 __mptcp_clean_una_wakeup(sk);
2360 rtx_head = mptcp_rtx_head(sk);
2361 if (!rtx_head) {
2362 mptcp_data_unlock(sk);
2363 return false;
2364 }
2365
2366 msk->recovery_snd_nxt = msk->snd_nxt;
2367 msk->recovery = true;
2368 mptcp_data_unlock(sk);
2369
2370 msk->first_pending = rtx_head;
2371 msk->snd_burst = 0;
2372
2373 /* be sure to clear the "sent status" on all re-injected fragments */
2374 list_for_each_entry(cur, &msk->rtx_queue, list) {
2375 if (!cur->already_sent)
2376 break;
2377 cur->already_sent = 0;
2378 }
2379
2380 return true;
2381 }
2382
2383 /* flags for __mptcp_close_ssk() */
2384 #define MPTCP_CF_PUSH BIT(1)
2385 #define MPTCP_CF_FASTCLOSE BIT(2)
2386
2387 /* be sure to send a reset only if the caller asked for it, also
2388 * clean completely the subflow status when the subflow reaches
2389 * TCP_CLOSE state
2390 */
__mptcp_subflow_disconnect(struct sock * ssk,struct mptcp_subflow_context * subflow,unsigned int flags)2391 static void __mptcp_subflow_disconnect(struct sock *ssk,
2392 struct mptcp_subflow_context *subflow,
2393 unsigned int flags)
2394 {
2395 if (((1 << ssk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) ||
2396 (flags & MPTCP_CF_FASTCLOSE)) {
2397 /* The MPTCP code never wait on the subflow sockets, TCP-level
2398 * disconnect should never fail
2399 */
2400 WARN_ON_ONCE(tcp_disconnect(ssk, 0));
2401 mptcp_subflow_ctx_reset(subflow);
2402 } else {
2403 tcp_shutdown(ssk, SEND_SHUTDOWN);
2404 }
2405 }
2406
2407 /* subflow sockets can be either outgoing (connect) or incoming
2408 * (accept).
2409 *
2410 * Outgoing subflows use in-kernel sockets.
2411 * Incoming subflows do not have their own 'struct socket' allocated,
2412 * so we need to use tcp_close() after detaching them from the mptcp
2413 * parent socket.
2414 */
__mptcp_close_ssk(struct sock * sk,struct sock * ssk,struct mptcp_subflow_context * subflow,unsigned int flags)2415 static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
2416 struct mptcp_subflow_context *subflow,
2417 unsigned int flags)
2418 {
2419 struct mptcp_sock *msk = mptcp_sk(sk);
2420 bool dispose_it, need_push = false;
2421
2422 /* If the first subflow moved to a close state before accept, e.g. due
2423 * to an incoming reset or listener shutdown, the subflow socket is
2424 * already deleted by inet_child_forget() and the mptcp socket can't
2425 * survive too.
2426 */
2427 if (msk->in_accept_queue && msk->first == ssk &&
2428 (sock_flag(sk, SOCK_DEAD) || sock_flag(ssk, SOCK_DEAD))) {
2429 /* ensure later check in mptcp_worker() will dispose the msk */
2430 sock_set_flag(sk, SOCK_DEAD);
2431 mptcp_set_close_tout(sk, tcp_jiffies32 - (mptcp_close_timeout(sk) + 1));
2432 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
2433 mptcp_subflow_drop_ctx(ssk);
2434 goto out_release;
2435 }
2436
2437 dispose_it = msk->free_first || ssk != msk->first;
2438 if (dispose_it)
2439 list_del(&subflow->node);
2440
2441 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
2442
2443 if ((flags & MPTCP_CF_FASTCLOSE) && !__mptcp_check_fallback(msk)) {
2444 /* be sure to force the tcp_close path
2445 * to generate the egress reset
2446 */
2447 ssk->sk_lingertime = 0;
2448 sock_set_flag(ssk, SOCK_LINGER);
2449 subflow->send_fastclose = 1;
2450 }
2451
2452 need_push = (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(sk);
2453 if (!dispose_it) {
2454 __mptcp_subflow_disconnect(ssk, subflow, flags);
2455 release_sock(ssk);
2456
2457 goto out;
2458 }
2459
2460 subflow->disposable = 1;
2461
2462 /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops
2463 * the ssk has been already destroyed, we just need to release the
2464 * reference owned by msk;
2465 */
2466 if (!inet_csk(ssk)->icsk_ulp_ops) {
2467 WARN_ON_ONCE(!sock_flag(ssk, SOCK_DEAD));
2468 kfree_rcu(subflow, rcu);
2469 } else {
2470 /* otherwise tcp will dispose of the ssk and subflow ctx */
2471 __tcp_close(ssk, 0);
2472
2473 /* close acquired an extra ref */
2474 __sock_put(ssk);
2475 }
2476
2477 out_release:
2478 __mptcp_subflow_error_report(sk, ssk);
2479 release_sock(ssk);
2480
2481 sock_put(ssk);
2482
2483 if (ssk == msk->first)
2484 WRITE_ONCE(msk->first, NULL);
2485
2486 out:
2487 __mptcp_sync_sndbuf(sk);
2488 if (need_push)
2489 __mptcp_push_pending(sk, 0);
2490
2491 /* Catch every 'all subflows closed' scenario, including peers silently
2492 * closing them, e.g. due to timeout.
2493 * For established sockets, allow an additional timeout before closing,
2494 * as the protocol can still create more subflows.
2495 */
2496 if (list_is_singular(&msk->conn_list) && msk->first &&
2497 inet_sk_state_load(msk->first) == TCP_CLOSE) {
2498 if (sk->sk_state != TCP_ESTABLISHED ||
2499 msk->in_accept_queue || sock_flag(sk, SOCK_DEAD)) {
2500 mptcp_set_state(sk, TCP_CLOSE);
2501 mptcp_close_wake_up(sk);
2502 } else {
2503 mptcp_start_tout_timer(sk);
2504 }
2505 }
2506 }
2507
mptcp_close_ssk(struct sock * sk,struct sock * ssk,struct mptcp_subflow_context * subflow)2508 void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
2509 struct mptcp_subflow_context *subflow)
2510 {
2511 /* The first subflow can already be closed and still in the list */
2512 if (subflow->close_event_done)
2513 return;
2514
2515 subflow->close_event_done = true;
2516
2517 if (sk->sk_state == TCP_ESTABLISHED)
2518 mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL);
2519
2520 /* subflow aborted before reaching the fully_established status
2521 * attempt the creation of the next subflow
2522 */
2523 mptcp_pm_subflow_check_next(mptcp_sk(sk), subflow);
2524
2525 __mptcp_close_ssk(sk, ssk, subflow, MPTCP_CF_PUSH);
2526 }
2527
mptcp_sync_mss(struct sock * sk,u32 pmtu)2528 static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu)
2529 {
2530 return 0;
2531 }
2532
__mptcp_close_subflow(struct sock * sk)2533 static void __mptcp_close_subflow(struct sock *sk)
2534 {
2535 struct mptcp_subflow_context *subflow, *tmp;
2536 struct mptcp_sock *msk = mptcp_sk(sk);
2537
2538 might_sleep();
2539
2540 mptcp_for_each_subflow_safe(msk, subflow, tmp) {
2541 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2542 int ssk_state = inet_sk_state_load(ssk);
2543
2544 if (ssk_state != TCP_CLOSE &&
2545 (ssk_state != TCP_CLOSE_WAIT ||
2546 inet_sk_state_load(sk) != TCP_ESTABLISHED))
2547 continue;
2548
2549 /* 'subflow_data_ready' will re-sched once rx queue is empty */
2550 if (!skb_queue_empty_lockless(&ssk->sk_receive_queue))
2551 continue;
2552
2553 mptcp_close_ssk(sk, ssk, subflow);
2554 }
2555
2556 }
2557
mptcp_close_tout_expired(const struct sock * sk)2558 static bool mptcp_close_tout_expired(const struct sock *sk)
2559 {
2560 if (!inet_csk(sk)->icsk_mtup.probe_timestamp ||
2561 sk->sk_state == TCP_CLOSE)
2562 return false;
2563
2564 return time_after32(tcp_jiffies32,
2565 inet_csk(sk)->icsk_mtup.probe_timestamp + mptcp_close_timeout(sk));
2566 }
2567
mptcp_check_fastclose(struct mptcp_sock * msk)2568 static void mptcp_check_fastclose(struct mptcp_sock *msk)
2569 {
2570 struct mptcp_subflow_context *subflow, *tmp;
2571 struct sock *sk = (struct sock *)msk;
2572
2573 if (likely(!READ_ONCE(msk->rcv_fastclose)))
2574 return;
2575
2576 mptcp_token_destroy(msk);
2577
2578 mptcp_for_each_subflow_safe(msk, subflow, tmp) {
2579 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
2580 bool slow;
2581
2582 slow = lock_sock_fast(tcp_sk);
2583 if (tcp_sk->sk_state != TCP_CLOSE) {
2584 mptcp_send_active_reset_reason(tcp_sk);
2585 tcp_set_state(tcp_sk, TCP_CLOSE);
2586 }
2587 unlock_sock_fast(tcp_sk, slow);
2588 }
2589
2590 /* Mirror the tcp_reset() error propagation */
2591 switch (sk->sk_state) {
2592 case TCP_SYN_SENT:
2593 WRITE_ONCE(sk->sk_err, ECONNREFUSED);
2594 break;
2595 case TCP_CLOSE_WAIT:
2596 WRITE_ONCE(sk->sk_err, EPIPE);
2597 break;
2598 case TCP_CLOSE:
2599 return;
2600 default:
2601 WRITE_ONCE(sk->sk_err, ECONNRESET);
2602 }
2603
2604 mptcp_set_state(sk, TCP_CLOSE);
2605 WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
2606 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
2607 set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags);
2608
2609 /* the calling mptcp_worker will properly destroy the socket */
2610 if (sock_flag(sk, SOCK_DEAD))
2611 return;
2612
2613 sk->sk_state_change(sk);
2614 sk_error_report(sk);
2615 }
2616
__mptcp_retrans(struct sock * sk)2617 static void __mptcp_retrans(struct sock *sk)
2618 {
2619 struct mptcp_sock *msk = mptcp_sk(sk);
2620 struct mptcp_subflow_context *subflow;
2621 struct mptcp_sendmsg_info info = {};
2622 struct mptcp_data_frag *dfrag;
2623 struct sock *ssk;
2624 int ret, err;
2625 u16 len = 0;
2626
2627 mptcp_clean_una_wakeup(sk);
2628
2629 /* first check ssk: need to kick "stale" logic */
2630 err = mptcp_sched_get_retrans(msk);
2631 dfrag = mptcp_rtx_head(sk);
2632 if (!dfrag) {
2633 if (mptcp_data_fin_enabled(msk)) {
2634 struct inet_connection_sock *icsk = inet_csk(sk);
2635
2636 icsk->icsk_retransmits++;
2637 mptcp_set_datafin_timeout(sk);
2638 mptcp_send_ack(msk);
2639
2640 goto reset_timer;
2641 }
2642
2643 if (!mptcp_send_head(sk))
2644 return;
2645
2646 goto reset_timer;
2647 }
2648
2649 if (err)
2650 goto reset_timer;
2651
2652 mptcp_for_each_subflow(msk, subflow) {
2653 if (READ_ONCE(subflow->scheduled)) {
2654 u16 copied = 0;
2655
2656 mptcp_subflow_set_scheduled(subflow, false);
2657
2658 ssk = mptcp_subflow_tcp_sock(subflow);
2659
2660 lock_sock(ssk);
2661
2662 /* limit retransmission to the bytes already sent on some subflows */
2663 info.sent = 0;
2664 info.limit = READ_ONCE(msk->csum_enabled) ? dfrag->data_len :
2665 dfrag->already_sent;
2666 while (info.sent < info.limit) {
2667 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
2668 if (ret <= 0)
2669 break;
2670
2671 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS);
2672 copied += ret;
2673 info.sent += ret;
2674 }
2675 if (copied) {
2676 len = max(copied, len);
2677 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
2678 info.size_goal);
2679 WRITE_ONCE(msk->allow_infinite_fallback, false);
2680 }
2681
2682 release_sock(ssk);
2683 }
2684 }
2685
2686 msk->bytes_retrans += len;
2687 dfrag->already_sent = max(dfrag->already_sent, len);
2688
2689 reset_timer:
2690 mptcp_check_and_set_pending(sk);
2691
2692 if (!mptcp_rtx_timer_pending(sk))
2693 mptcp_reset_rtx_timer(sk);
2694 }
2695
2696 /* schedule the timeout timer for the relevant event: either close timeout
2697 * or mp_fail timeout. The close timeout takes precedence on the mp_fail one
2698 */
mptcp_reset_tout_timer(struct mptcp_sock * msk,unsigned long fail_tout)2699 void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout)
2700 {
2701 struct sock *sk = (struct sock *)msk;
2702 unsigned long timeout, close_timeout;
2703
2704 if (!fail_tout && !inet_csk(sk)->icsk_mtup.probe_timestamp)
2705 return;
2706
2707 close_timeout = inet_csk(sk)->icsk_mtup.probe_timestamp - tcp_jiffies32 + jiffies +
2708 mptcp_close_timeout(sk);
2709
2710 /* the close timeout takes precedence on the fail one, and here at least one of
2711 * them is active
2712 */
2713 timeout = inet_csk(sk)->icsk_mtup.probe_timestamp ? close_timeout : fail_tout;
2714
2715 sk_reset_timer(sk, &sk->sk_timer, timeout);
2716 }
2717
mptcp_mp_fail_no_response(struct mptcp_sock * msk)2718 static void mptcp_mp_fail_no_response(struct mptcp_sock *msk)
2719 {
2720 struct sock *ssk = msk->first;
2721 bool slow;
2722
2723 if (!ssk)
2724 return;
2725
2726 pr_debug("MP_FAIL doesn't respond, reset the subflow\n");
2727
2728 slow = lock_sock_fast(ssk);
2729 mptcp_subflow_reset(ssk);
2730 WRITE_ONCE(mptcp_subflow_ctx(ssk)->fail_tout, 0);
2731 unlock_sock_fast(ssk, slow);
2732 }
2733
mptcp_do_fastclose(struct sock * sk)2734 static void mptcp_do_fastclose(struct sock *sk)
2735 {
2736 struct mptcp_subflow_context *subflow, *tmp;
2737 struct mptcp_sock *msk = mptcp_sk(sk);
2738
2739 mptcp_set_state(sk, TCP_CLOSE);
2740 mptcp_for_each_subflow_safe(msk, subflow, tmp)
2741 __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow),
2742 subflow, MPTCP_CF_FASTCLOSE);
2743 }
2744
mptcp_worker(struct work_struct * work)2745 static void mptcp_worker(struct work_struct *work)
2746 {
2747 struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
2748 struct sock *sk = (struct sock *)msk;
2749 unsigned long fail_tout;
2750 int state;
2751
2752 lock_sock(sk);
2753 state = sk->sk_state;
2754 if (unlikely((1 << state) & (TCPF_CLOSE | TCPF_LISTEN)))
2755 goto unlock;
2756
2757 mptcp_check_fastclose(msk);
2758
2759 mptcp_pm_nl_work(msk);
2760
2761 mptcp_check_send_data_fin(sk);
2762 mptcp_check_data_fin_ack(sk);
2763 mptcp_check_data_fin(sk);
2764
2765 if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
2766 __mptcp_close_subflow(sk);
2767
2768 if (mptcp_close_tout_expired(sk)) {
2769 mptcp_do_fastclose(sk);
2770 mptcp_close_wake_up(sk);
2771 }
2772
2773 if (sock_flag(sk, SOCK_DEAD) && sk->sk_state == TCP_CLOSE) {
2774 __mptcp_destroy_sock(sk);
2775 goto unlock;
2776 }
2777
2778 if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
2779 __mptcp_retrans(sk);
2780
2781 fail_tout = msk->first ? READ_ONCE(mptcp_subflow_ctx(msk->first)->fail_tout) : 0;
2782 if (fail_tout && time_after(jiffies, fail_tout))
2783 mptcp_mp_fail_no_response(msk);
2784
2785 unlock:
2786 release_sock(sk);
2787 sock_put(sk);
2788 }
2789
__mptcp_init_sock(struct sock * sk)2790 static void __mptcp_init_sock(struct sock *sk)
2791 {
2792 struct mptcp_sock *msk = mptcp_sk(sk);
2793
2794 INIT_LIST_HEAD(&msk->conn_list);
2795 INIT_LIST_HEAD(&msk->join_list);
2796 INIT_LIST_HEAD(&msk->rtx_queue);
2797 INIT_WORK(&msk->work, mptcp_worker);
2798 __skb_queue_head_init(&msk->receive_queue);
2799 msk->out_of_order_queue = RB_ROOT;
2800 msk->first_pending = NULL;
2801 WRITE_ONCE(msk->rmem_fwd_alloc, 0);
2802 WRITE_ONCE(msk->rmem_released, 0);
2803 msk->timer_ival = TCP_RTO_MIN;
2804 msk->scaling_ratio = TCP_DEFAULT_SCALING_RATIO;
2805
2806 WRITE_ONCE(msk->first, NULL);
2807 inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss;
2808 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
2809 WRITE_ONCE(msk->allow_infinite_fallback, true);
2810 msk->recovery = false;
2811 msk->subflow_id = 1;
2812 msk->last_data_sent = tcp_jiffies32;
2813 msk->last_data_recv = tcp_jiffies32;
2814 msk->last_ack_recv = tcp_jiffies32;
2815
2816 mptcp_pm_data_init(msk);
2817
2818 /* re-use the csk retrans timer for MPTCP-level retrans */
2819 timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0);
2820 timer_setup(&sk->sk_timer, mptcp_tout_timer, 0);
2821 }
2822
mptcp_ca_reset(struct sock * sk)2823 static void mptcp_ca_reset(struct sock *sk)
2824 {
2825 struct inet_connection_sock *icsk = inet_csk(sk);
2826
2827 tcp_assign_congestion_control(sk);
2828 strscpy(mptcp_sk(sk)->ca_name, icsk->icsk_ca_ops->name,
2829 sizeof(mptcp_sk(sk)->ca_name));
2830
2831 /* no need to keep a reference to the ops, the name will suffice */
2832 tcp_cleanup_congestion_control(sk);
2833 icsk->icsk_ca_ops = NULL;
2834 }
2835
mptcp_init_sock(struct sock * sk)2836 static int mptcp_init_sock(struct sock *sk)
2837 {
2838 struct net *net = sock_net(sk);
2839 int ret;
2840
2841 __mptcp_init_sock(sk);
2842
2843 if (!mptcp_is_enabled(net))
2844 return -ENOPROTOOPT;
2845
2846 if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net))
2847 return -ENOMEM;
2848
2849 ret = mptcp_init_sched(mptcp_sk(sk),
2850 mptcp_sched_find(mptcp_get_scheduler(net)));
2851 if (ret)
2852 return ret;
2853
2854 set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags);
2855
2856 /* fetch the ca name; do it outside __mptcp_init_sock(), so that clone will
2857 * propagate the correct value
2858 */
2859 mptcp_ca_reset(sk);
2860
2861 sk_sockets_allocated_inc(sk);
2862 sk->sk_rcvbuf = READ_ONCE(net->ipv4.sysctl_tcp_rmem[1]);
2863 sk->sk_sndbuf = READ_ONCE(net->ipv4.sysctl_tcp_wmem[1]);
2864
2865 return 0;
2866 }
2867
__mptcp_clear_xmit(struct sock * sk)2868 static void __mptcp_clear_xmit(struct sock *sk)
2869 {
2870 struct mptcp_sock *msk = mptcp_sk(sk);
2871 struct mptcp_data_frag *dtmp, *dfrag;
2872
2873 WRITE_ONCE(msk->first_pending, NULL);
2874 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list)
2875 dfrag_clear(sk, dfrag);
2876 }
2877
mptcp_cancel_work(struct sock * sk)2878 void mptcp_cancel_work(struct sock *sk)
2879 {
2880 struct mptcp_sock *msk = mptcp_sk(sk);
2881
2882 if (cancel_work_sync(&msk->work))
2883 __sock_put(sk);
2884 }
2885
mptcp_subflow_shutdown(struct sock * sk,struct sock * ssk,int how)2886 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how)
2887 {
2888 lock_sock(ssk);
2889
2890 switch (ssk->sk_state) {
2891 case TCP_LISTEN:
2892 if (!(how & RCV_SHUTDOWN))
2893 break;
2894 fallthrough;
2895 case TCP_SYN_SENT:
2896 WARN_ON_ONCE(tcp_disconnect(ssk, O_NONBLOCK));
2897 break;
2898 default:
2899 if (__mptcp_check_fallback(mptcp_sk(sk))) {
2900 pr_debug("Fallback\n");
2901 ssk->sk_shutdown |= how;
2902 tcp_shutdown(ssk, how);
2903
2904 /* simulate the data_fin ack reception to let the state
2905 * machine move forward
2906 */
2907 WRITE_ONCE(mptcp_sk(sk)->snd_una, mptcp_sk(sk)->snd_nxt);
2908 mptcp_schedule_work(sk);
2909 } else {
2910 pr_debug("Sending DATA_FIN on subflow %p\n", ssk);
2911 tcp_send_ack(ssk);
2912 if (!mptcp_rtx_timer_pending(sk))
2913 mptcp_reset_rtx_timer(sk);
2914 }
2915 break;
2916 }
2917
2918 release_sock(ssk);
2919 }
2920
mptcp_set_state(struct sock * sk,int state)2921 void mptcp_set_state(struct sock *sk, int state)
2922 {
2923 int oldstate = sk->sk_state;
2924
2925 switch (state) {
2926 case TCP_ESTABLISHED:
2927 if (oldstate != TCP_ESTABLISHED)
2928 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_CURRESTAB);
2929 break;
2930 case TCP_CLOSE_WAIT:
2931 /* Unlike TCP, MPTCP sk would not have the TCP_SYN_RECV state:
2932 * MPTCP "accepted" sockets will be created later on. So no
2933 * transition from TCP_SYN_RECV to TCP_CLOSE_WAIT.
2934 */
2935 break;
2936 default:
2937 if (oldstate == TCP_ESTABLISHED || oldstate == TCP_CLOSE_WAIT)
2938 MPTCP_DEC_STATS(sock_net(sk), MPTCP_MIB_CURRESTAB);
2939 }
2940
2941 inet_sk_state_store(sk, state);
2942 }
2943
2944 static const unsigned char new_state[16] = {
2945 /* current state: new state: action: */
2946 [0 /* (Invalid) */] = TCP_CLOSE,
2947 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2948 [TCP_SYN_SENT] = TCP_CLOSE,
2949 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2950 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1,
2951 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2,
2952 [TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */
2953 [TCP_CLOSE] = TCP_CLOSE,
2954 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN,
2955 [TCP_LAST_ACK] = TCP_LAST_ACK,
2956 [TCP_LISTEN] = TCP_CLOSE,
2957 [TCP_CLOSING] = TCP_CLOSING,
2958 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */
2959 };
2960
mptcp_close_state(struct sock * sk)2961 static int mptcp_close_state(struct sock *sk)
2962 {
2963 int next = (int)new_state[sk->sk_state];
2964 int ns = next & TCP_STATE_MASK;
2965
2966 mptcp_set_state(sk, ns);
2967
2968 return next & TCP_ACTION_FIN;
2969 }
2970
mptcp_check_send_data_fin(struct sock * sk)2971 static void mptcp_check_send_data_fin(struct sock *sk)
2972 {
2973 struct mptcp_subflow_context *subflow;
2974 struct mptcp_sock *msk = mptcp_sk(sk);
2975
2976 pr_debug("msk=%p snd_data_fin_enable=%d pending=%d snd_nxt=%llu write_seq=%llu\n",
2977 msk, msk->snd_data_fin_enable, !!mptcp_send_head(sk),
2978 msk->snd_nxt, msk->write_seq);
2979
2980 /* we still need to enqueue subflows or not really shutting down,
2981 * skip this
2982 */
2983 if (!msk->snd_data_fin_enable || msk->snd_nxt + 1 != msk->write_seq ||
2984 mptcp_send_head(sk))
2985 return;
2986
2987 WRITE_ONCE(msk->snd_nxt, msk->write_seq);
2988
2989 mptcp_for_each_subflow(msk, subflow) {
2990 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
2991
2992 mptcp_subflow_shutdown(sk, tcp_sk, SEND_SHUTDOWN);
2993 }
2994 }
2995
__mptcp_wr_shutdown(struct sock * sk)2996 static void __mptcp_wr_shutdown(struct sock *sk)
2997 {
2998 struct mptcp_sock *msk = mptcp_sk(sk);
2999
3000 pr_debug("msk=%p snd_data_fin_enable=%d shutdown=%x state=%d pending=%d\n",
3001 msk, msk->snd_data_fin_enable, sk->sk_shutdown, sk->sk_state,
3002 !!mptcp_send_head(sk));
3003
3004 /* will be ignored by fallback sockets */
3005 WRITE_ONCE(msk->write_seq, msk->write_seq + 1);
3006 WRITE_ONCE(msk->snd_data_fin_enable, 1);
3007
3008 mptcp_check_send_data_fin(sk);
3009 }
3010
__mptcp_destroy_sock(struct sock * sk)3011 static void __mptcp_destroy_sock(struct sock *sk)
3012 {
3013 struct mptcp_sock *msk = mptcp_sk(sk);
3014
3015 pr_debug("msk=%p\n", msk);
3016
3017 might_sleep();
3018
3019 mptcp_stop_rtx_timer(sk);
3020 sk_stop_timer(sk, &sk->sk_timer);
3021 msk->pm.status = 0;
3022 mptcp_release_sched(msk);
3023
3024 sk->sk_prot->destroy(sk);
3025
3026 WARN_ON_ONCE(READ_ONCE(msk->rmem_fwd_alloc));
3027 WARN_ON_ONCE(msk->rmem_released);
3028 sk_stream_kill_queues(sk);
3029 xfrm_sk_free_policy(sk);
3030
3031 sock_put(sk);
3032 }
3033
__mptcp_unaccepted_force_close(struct sock * sk)3034 void __mptcp_unaccepted_force_close(struct sock *sk)
3035 {
3036 sock_set_flag(sk, SOCK_DEAD);
3037 mptcp_do_fastclose(sk);
3038 __mptcp_destroy_sock(sk);
3039 }
3040
mptcp_check_readable(struct sock * sk)3041 static __poll_t mptcp_check_readable(struct sock *sk)
3042 {
3043 return mptcp_epollin_ready(sk) ? EPOLLIN | EPOLLRDNORM : 0;
3044 }
3045
mptcp_check_listen_stop(struct sock * sk)3046 static void mptcp_check_listen_stop(struct sock *sk)
3047 {
3048 struct sock *ssk;
3049
3050 if (inet_sk_state_load(sk) != TCP_LISTEN)
3051 return;
3052
3053 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
3054 ssk = mptcp_sk(sk)->first;
3055 if (WARN_ON_ONCE(!ssk || inet_sk_state_load(ssk) != TCP_LISTEN))
3056 return;
3057
3058 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
3059 tcp_set_state(ssk, TCP_CLOSE);
3060 mptcp_subflow_queue_clean(sk, ssk);
3061 inet_csk_listen_stop(ssk);
3062 mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CLOSED);
3063 release_sock(ssk);
3064 }
3065
__mptcp_close(struct sock * sk,long timeout)3066 bool __mptcp_close(struct sock *sk, long timeout)
3067 {
3068 struct mptcp_subflow_context *subflow;
3069 struct mptcp_sock *msk = mptcp_sk(sk);
3070 bool do_cancel_work = false;
3071 int subflows_alive = 0;
3072
3073 WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
3074
3075 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) {
3076 mptcp_check_listen_stop(sk);
3077 mptcp_set_state(sk, TCP_CLOSE);
3078 goto cleanup;
3079 }
3080
3081 if (mptcp_data_avail(msk) || timeout < 0) {
3082 /* If the msk has read data, or the caller explicitly ask it,
3083 * do the MPTCP equivalent of TCP reset, aka MPTCP fastclose
3084 */
3085 mptcp_do_fastclose(sk);
3086 timeout = 0;
3087 } else if (mptcp_close_state(sk)) {
3088 __mptcp_wr_shutdown(sk);
3089 }
3090
3091 sk_stream_wait_close(sk, timeout);
3092
3093 cleanup:
3094 /* orphan all the subflows */
3095 mptcp_for_each_subflow(msk, subflow) {
3096 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3097 bool slow = lock_sock_fast_nested(ssk);
3098
3099 subflows_alive += ssk->sk_state != TCP_CLOSE;
3100
3101 /* since the close timeout takes precedence on the fail one,
3102 * cancel the latter
3103 */
3104 if (ssk == msk->first)
3105 subflow->fail_tout = 0;
3106
3107 /* detach from the parent socket, but allow data_ready to
3108 * push incoming data into the mptcp stack, to properly ack it
3109 */
3110 ssk->sk_socket = NULL;
3111 ssk->sk_wq = NULL;
3112 unlock_sock_fast(ssk, slow);
3113 }
3114 sock_orphan(sk);
3115
3116 /* all the subflows are closed, only timeout can change the msk
3117 * state, let's not keep resources busy for no reasons
3118 */
3119 if (subflows_alive == 0)
3120 mptcp_set_state(sk, TCP_CLOSE);
3121
3122 sock_hold(sk);
3123 pr_debug("msk=%p state=%d\n", sk, sk->sk_state);
3124 if (msk->token)
3125 mptcp_event(MPTCP_EVENT_CLOSED, msk, NULL, GFP_KERNEL);
3126
3127 if (sk->sk_state == TCP_CLOSE) {
3128 __mptcp_destroy_sock(sk);
3129 do_cancel_work = true;
3130 } else {
3131 mptcp_start_tout_timer(sk);
3132 }
3133
3134 return do_cancel_work;
3135 }
3136
mptcp_close(struct sock * sk,long timeout)3137 static void mptcp_close(struct sock *sk, long timeout)
3138 {
3139 bool do_cancel_work;
3140
3141 lock_sock(sk);
3142
3143 do_cancel_work = __mptcp_close(sk, timeout);
3144 release_sock(sk);
3145 if (do_cancel_work)
3146 mptcp_cancel_work(sk);
3147
3148 sock_put(sk);
3149 }
3150
mptcp_copy_inaddrs(struct sock * msk,const struct sock * ssk)3151 static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk)
3152 {
3153 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
3154 const struct ipv6_pinfo *ssk6 = inet6_sk(ssk);
3155 struct ipv6_pinfo *msk6 = inet6_sk(msk);
3156
3157 msk->sk_v6_daddr = ssk->sk_v6_daddr;
3158 msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr;
3159
3160 if (msk6 && ssk6) {
3161 msk6->saddr = ssk6->saddr;
3162 msk6->flow_label = ssk6->flow_label;
3163 }
3164 #endif
3165
3166 inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num;
3167 inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport;
3168 inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport;
3169 inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr;
3170 inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr;
3171 inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr;
3172 }
3173
mptcp_disconnect(struct sock * sk,int flags)3174 static int mptcp_disconnect(struct sock *sk, int flags)
3175 {
3176 struct mptcp_sock *msk = mptcp_sk(sk);
3177
3178 /* We are on the fastopen error path. We can't call straight into the
3179 * subflows cleanup code due to lock nesting (we are already under
3180 * msk->firstsocket lock).
3181 */
3182 if (msk->fastopening)
3183 return -EBUSY;
3184
3185 mptcp_check_listen_stop(sk);
3186 mptcp_set_state(sk, TCP_CLOSE);
3187
3188 mptcp_stop_rtx_timer(sk);
3189 mptcp_stop_tout_timer(sk);
3190
3191 if (msk->token)
3192 mptcp_event(MPTCP_EVENT_CLOSED, msk, NULL, GFP_KERNEL);
3193
3194 /* msk->subflow is still intact, the following will not free the first
3195 * subflow
3196 */
3197 mptcp_destroy_common(msk, MPTCP_CF_FASTCLOSE);
3198 WRITE_ONCE(msk->flags, 0);
3199 msk->cb_flags = 0;
3200 msk->recovery = false;
3201 WRITE_ONCE(msk->can_ack, false);
3202 WRITE_ONCE(msk->fully_established, false);
3203 WRITE_ONCE(msk->rcv_data_fin, false);
3204 WRITE_ONCE(msk->snd_data_fin_enable, false);
3205 WRITE_ONCE(msk->rcv_fastclose, false);
3206 WRITE_ONCE(msk->use_64bit_ack, false);
3207 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
3208 mptcp_pm_data_reset(msk);
3209 mptcp_ca_reset(sk);
3210 msk->bytes_consumed = 0;
3211 msk->bytes_acked = 0;
3212 msk->bytes_received = 0;
3213 msk->bytes_sent = 0;
3214 msk->bytes_retrans = 0;
3215 msk->rcvspace_init = 0;
3216
3217 WRITE_ONCE(sk->sk_shutdown, 0);
3218 sk_error_report(sk);
3219 return 0;
3220 }
3221
3222 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
mptcp_inet6_sk(const struct sock * sk)3223 static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk)
3224 {
3225 unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo);
3226
3227 return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
3228 }
3229
mptcp_copy_ip6_options(struct sock * newsk,const struct sock * sk)3230 static void mptcp_copy_ip6_options(struct sock *newsk, const struct sock *sk)
3231 {
3232 const struct ipv6_pinfo *np = inet6_sk(sk);
3233 struct ipv6_txoptions *opt;
3234 struct ipv6_pinfo *newnp;
3235
3236 newnp = inet6_sk(newsk);
3237
3238 rcu_read_lock();
3239 opt = rcu_dereference(np->opt);
3240 if (opt) {
3241 opt = ipv6_dup_options(newsk, opt);
3242 if (!opt)
3243 net_warn_ratelimited("%s: Failed to copy ip6 options\n", __func__);
3244 }
3245 RCU_INIT_POINTER(newnp->opt, opt);
3246 rcu_read_unlock();
3247 }
3248 #endif
3249
mptcp_copy_ip_options(struct sock * newsk,const struct sock * sk)3250 static void mptcp_copy_ip_options(struct sock *newsk, const struct sock *sk)
3251 {
3252 struct ip_options_rcu *inet_opt, *newopt = NULL;
3253 const struct inet_sock *inet = inet_sk(sk);
3254 struct inet_sock *newinet;
3255
3256 newinet = inet_sk(newsk);
3257
3258 rcu_read_lock();
3259 inet_opt = rcu_dereference(inet->inet_opt);
3260 if (inet_opt) {
3261 newopt = sock_kmalloc(newsk, sizeof(*inet_opt) +
3262 inet_opt->opt.optlen, GFP_ATOMIC);
3263 if (newopt)
3264 memcpy(newopt, inet_opt, sizeof(*inet_opt) +
3265 inet_opt->opt.optlen);
3266 else
3267 net_warn_ratelimited("%s: Failed to copy ip options\n", __func__);
3268 }
3269 RCU_INIT_POINTER(newinet->inet_opt, newopt);
3270 rcu_read_unlock();
3271 }
3272
mptcp_sk_clone_init(const struct sock * sk,const struct mptcp_options_received * mp_opt,struct sock * ssk,struct request_sock * req)3273 struct sock *mptcp_sk_clone_init(const struct sock *sk,
3274 const struct mptcp_options_received *mp_opt,
3275 struct sock *ssk,
3276 struct request_sock *req)
3277 {
3278 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
3279 struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC);
3280 struct mptcp_subflow_context *subflow;
3281 struct mptcp_sock *msk;
3282
3283 if (!nsk)
3284 return NULL;
3285
3286 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
3287 if (nsk->sk_family == AF_INET6)
3288 inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk);
3289 #endif
3290
3291 __mptcp_init_sock(nsk);
3292
3293 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
3294 if (nsk->sk_family == AF_INET6)
3295 mptcp_copy_ip6_options(nsk, sk);
3296 else
3297 #endif
3298 mptcp_copy_ip_options(nsk, sk);
3299
3300 msk = mptcp_sk(nsk);
3301 WRITE_ONCE(msk->local_key, subflow_req->local_key);
3302 WRITE_ONCE(msk->token, subflow_req->token);
3303 msk->in_accept_queue = 1;
3304 WRITE_ONCE(msk->fully_established, false);
3305 if (mp_opt->suboptions & OPTION_MPTCP_CSUMREQD)
3306 WRITE_ONCE(msk->csum_enabled, true);
3307
3308 WRITE_ONCE(msk->write_seq, subflow_req->idsn + 1);
3309 WRITE_ONCE(msk->snd_nxt, msk->write_seq);
3310 WRITE_ONCE(msk->snd_una, msk->write_seq);
3311 WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd);
3312 msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq;
3313 mptcp_init_sched(msk, mptcp_sk(sk)->sched);
3314
3315 /* passive msk is created after the first/MPC subflow */
3316 msk->subflow_id = 2;
3317
3318 sock_reset_flag(nsk, SOCK_RCU_FREE);
3319 security_inet_csk_clone(nsk, req);
3320
3321 /* this can't race with mptcp_close(), as the msk is
3322 * not yet exposted to user-space
3323 */
3324 mptcp_set_state(nsk, TCP_ESTABLISHED);
3325
3326 /* The msk maintain a ref to each subflow in the connections list */
3327 WRITE_ONCE(msk->first, ssk);
3328 subflow = mptcp_subflow_ctx(ssk);
3329 list_add(&subflow->node, &msk->conn_list);
3330 sock_hold(ssk);
3331
3332 /* new mpc subflow takes ownership of the newly
3333 * created mptcp socket
3334 */
3335 mptcp_token_accept(subflow_req, msk);
3336
3337 /* set msk addresses early to ensure mptcp_pm_get_local_id()
3338 * uses the correct data
3339 */
3340 mptcp_copy_inaddrs(nsk, ssk);
3341 __mptcp_propagate_sndbuf(nsk, ssk);
3342
3343 mptcp_rcv_space_init(msk, ssk);
3344
3345 if (mp_opt->suboptions & OPTION_MPTCP_MPC_ACK)
3346 __mptcp_subflow_fully_established(msk, subflow, mp_opt);
3347 bh_unlock_sock(nsk);
3348
3349 /* note: the newly allocated socket refcount is 2 now */
3350 return nsk;
3351 }
3352
mptcp_rcv_space_init(struct mptcp_sock * msk,const struct sock * ssk)3353 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk)
3354 {
3355 const struct tcp_sock *tp = tcp_sk(ssk);
3356
3357 msk->rcvspace_init = 1;
3358 msk->rcvq_space.copied = 0;
3359 msk->rcvq_space.rtt_us = 0;
3360
3361 msk->rcvq_space.time = tp->tcp_mstamp;
3362
3363 /* initial rcv_space offering made to peer */
3364 msk->rcvq_space.space = min_t(u32, tp->rcv_wnd,
3365 TCP_INIT_CWND * tp->advmss);
3366 if (msk->rcvq_space.space == 0)
3367 msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT;
3368 }
3369
mptcp_destroy_common(struct mptcp_sock * msk,unsigned int flags)3370 void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags)
3371 {
3372 struct mptcp_subflow_context *subflow, *tmp;
3373 struct sock *sk = (struct sock *)msk;
3374
3375 __mptcp_clear_xmit(sk);
3376
3377 /* join list will be eventually flushed (with rst) at sock lock release time */
3378 mptcp_for_each_subflow_safe(msk, subflow, tmp)
3379 __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), subflow, flags);
3380
3381 /* move to sk_receive_queue, sk_stream_kill_queues will purge it */
3382 mptcp_data_lock(sk);
3383 skb_queue_splice_tail_init(&msk->receive_queue, &sk->sk_receive_queue);
3384 __skb_queue_purge(&sk->sk_receive_queue);
3385 skb_rbtree_purge(&msk->out_of_order_queue);
3386 mptcp_data_unlock(sk);
3387
3388 /* move all the rx fwd alloc into the sk_mem_reclaim_final in
3389 * inet_sock_destruct() will dispose it
3390 */
3391 sk_forward_alloc_add(sk, msk->rmem_fwd_alloc);
3392 WRITE_ONCE(msk->rmem_fwd_alloc, 0);
3393 mptcp_token_destroy(msk);
3394 mptcp_pm_free_anno_list(msk);
3395 mptcp_free_local_addr_list(msk);
3396 }
3397
mptcp_destroy(struct sock * sk)3398 static void mptcp_destroy(struct sock *sk)
3399 {
3400 struct mptcp_sock *msk = mptcp_sk(sk);
3401
3402 /* allow the following to close even the initial subflow */
3403 msk->free_first = 1;
3404 mptcp_destroy_common(msk, 0);
3405 sk_sockets_allocated_dec(sk);
3406 }
3407
__mptcp_data_acked(struct sock * sk)3408 void __mptcp_data_acked(struct sock *sk)
3409 {
3410 if (!sock_owned_by_user(sk))
3411 __mptcp_clean_una(sk);
3412 else
3413 __set_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->cb_flags);
3414 }
3415
__mptcp_check_push(struct sock * sk,struct sock * ssk)3416 void __mptcp_check_push(struct sock *sk, struct sock *ssk)
3417 {
3418 if (!mptcp_send_head(sk))
3419 return;
3420
3421 if (!sock_owned_by_user(sk))
3422 __mptcp_subflow_push_pending(sk, ssk, false);
3423 else
3424 __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags);
3425 }
3426
3427 #define MPTCP_FLAGS_PROCESS_CTX_NEED (BIT(MPTCP_PUSH_PENDING) | \
3428 BIT(MPTCP_RETRANSMIT) | \
3429 BIT(MPTCP_FLUSH_JOIN_LIST))
3430
3431 /* processes deferred events and flush wmem */
mptcp_release_cb(struct sock * sk)3432 static void mptcp_release_cb(struct sock *sk)
3433 __must_hold(&sk->sk_lock.slock)
3434 {
3435 struct mptcp_sock *msk = mptcp_sk(sk);
3436
3437 for (;;) {
3438 unsigned long flags = (msk->cb_flags & MPTCP_FLAGS_PROCESS_CTX_NEED);
3439 struct list_head join_list;
3440
3441 if (!flags)
3442 break;
3443
3444 INIT_LIST_HEAD(&join_list);
3445 list_splice_init(&msk->join_list, &join_list);
3446
3447 /* the following actions acquire the subflow socket lock
3448 *
3449 * 1) can't be invoked in atomic scope
3450 * 2) must avoid ABBA deadlock with msk socket spinlock: the RX
3451 * datapath acquires the msk socket spinlock while helding
3452 * the subflow socket lock
3453 */
3454 msk->cb_flags &= ~flags;
3455 spin_unlock_bh(&sk->sk_lock.slock);
3456
3457 if (flags & BIT(MPTCP_FLUSH_JOIN_LIST))
3458 __mptcp_flush_join_list(sk, &join_list);
3459 if (flags & BIT(MPTCP_PUSH_PENDING))
3460 __mptcp_push_pending(sk, 0);
3461 if (flags & BIT(MPTCP_RETRANSMIT))
3462 __mptcp_retrans(sk);
3463
3464 cond_resched();
3465 spin_lock_bh(&sk->sk_lock.slock);
3466 }
3467
3468 if (__test_and_clear_bit(MPTCP_CLEAN_UNA, &msk->cb_flags))
3469 __mptcp_clean_una_wakeup(sk);
3470 if (unlikely(msk->cb_flags)) {
3471 /* be sure to sync the msk state before taking actions
3472 * depending on sk_state (MPTCP_ERROR_REPORT)
3473 * On sk release avoid actions depending on the first subflow
3474 */
3475 if (__test_and_clear_bit(MPTCP_SYNC_STATE, &msk->cb_flags) && msk->first)
3476 __mptcp_sync_state(sk, msk->pending_state);
3477 if (__test_and_clear_bit(MPTCP_ERROR_REPORT, &msk->cb_flags))
3478 __mptcp_error_report(sk);
3479 if (__test_and_clear_bit(MPTCP_SYNC_SNDBUF, &msk->cb_flags))
3480 __mptcp_sync_sndbuf(sk);
3481 }
3482
3483 __mptcp_update_rmem(sk);
3484 }
3485
3486 /* MP_JOIN client subflow must wait for 4th ack before sending any data:
3487 * TCP can't schedule delack timer before the subflow is fully established.
3488 * MPTCP uses the delack timer to do 3rd ack retransmissions
3489 */
schedule_3rdack_retransmission(struct sock * ssk)3490 static void schedule_3rdack_retransmission(struct sock *ssk)
3491 {
3492 struct inet_connection_sock *icsk = inet_csk(ssk);
3493 struct tcp_sock *tp = tcp_sk(ssk);
3494 unsigned long timeout;
3495
3496 if (mptcp_subflow_ctx(ssk)->fully_established)
3497 return;
3498
3499 /* reschedule with a timeout above RTT, as we must look only for drop */
3500 if (tp->srtt_us)
3501 timeout = usecs_to_jiffies(tp->srtt_us >> (3 - 1));
3502 else
3503 timeout = TCP_TIMEOUT_INIT;
3504 timeout += jiffies;
3505
3506 WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER);
3507 icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
3508 icsk->icsk_ack.timeout = timeout;
3509 sk_reset_timer(ssk, &icsk->icsk_delack_timer, timeout);
3510 }
3511
mptcp_subflow_process_delegated(struct sock * ssk,long status)3512 void mptcp_subflow_process_delegated(struct sock *ssk, long status)
3513 {
3514 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
3515 struct sock *sk = subflow->conn;
3516
3517 if (status & BIT(MPTCP_DELEGATE_SEND)) {
3518 mptcp_data_lock(sk);
3519 if (!sock_owned_by_user(sk))
3520 __mptcp_subflow_push_pending(sk, ssk, true);
3521 else
3522 __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags);
3523 mptcp_data_unlock(sk);
3524 }
3525 if (status & BIT(MPTCP_DELEGATE_SNDBUF)) {
3526 mptcp_data_lock(sk);
3527 if (!sock_owned_by_user(sk))
3528 __mptcp_sync_sndbuf(sk);
3529 else
3530 __set_bit(MPTCP_SYNC_SNDBUF, &mptcp_sk(sk)->cb_flags);
3531 mptcp_data_unlock(sk);
3532 }
3533 if (status & BIT(MPTCP_DELEGATE_ACK))
3534 schedule_3rdack_retransmission(ssk);
3535 }
3536
mptcp_hash(struct sock * sk)3537 static int mptcp_hash(struct sock *sk)
3538 {
3539 /* should never be called,
3540 * we hash the TCP subflows not the MPTCP socket
3541 */
3542 WARN_ON_ONCE(1);
3543 return 0;
3544 }
3545
mptcp_unhash(struct sock * sk)3546 static void mptcp_unhash(struct sock *sk)
3547 {
3548 /* called from sk_common_release(), but nothing to do here */
3549 }
3550
mptcp_get_port(struct sock * sk,unsigned short snum)3551 static int mptcp_get_port(struct sock *sk, unsigned short snum)
3552 {
3553 struct mptcp_sock *msk = mptcp_sk(sk);
3554
3555 pr_debug("msk=%p, ssk=%p\n", msk, msk->first);
3556 if (WARN_ON_ONCE(!msk->first))
3557 return -EINVAL;
3558
3559 return inet_csk_get_port(msk->first, snum);
3560 }
3561
mptcp_finish_connect(struct sock * ssk)3562 void mptcp_finish_connect(struct sock *ssk)
3563 {
3564 struct mptcp_subflow_context *subflow;
3565 struct mptcp_sock *msk;
3566 struct sock *sk;
3567
3568 subflow = mptcp_subflow_ctx(ssk);
3569 sk = subflow->conn;
3570 msk = mptcp_sk(sk);
3571
3572 pr_debug("msk=%p, token=%u\n", sk, subflow->token);
3573
3574 subflow->map_seq = subflow->iasn;
3575 subflow->map_subflow_seq = 1;
3576
3577 /* the socket is not connected yet, no msk/subflow ops can access/race
3578 * accessing the field below
3579 */
3580 WRITE_ONCE(msk->local_key, subflow->local_key);
3581
3582 mptcp_pm_new_connection(msk, ssk, 0);
3583 }
3584
mptcp_sock_graft(struct sock * sk,struct socket * parent)3585 void mptcp_sock_graft(struct sock *sk, struct socket *parent)
3586 {
3587 write_lock_bh(&sk->sk_callback_lock);
3588 rcu_assign_pointer(sk->sk_wq, &parent->wq);
3589 sk_set_socket(sk, parent);
3590 sk->sk_uid = SOCK_INODE(parent)->i_uid;
3591 write_unlock_bh(&sk->sk_callback_lock);
3592 }
3593
mptcp_finish_join(struct sock * ssk)3594 bool mptcp_finish_join(struct sock *ssk)
3595 {
3596 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
3597 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
3598 struct sock *parent = (void *)msk;
3599 bool ret = true;
3600
3601 pr_debug("msk=%p, subflow=%p\n", msk, subflow);
3602
3603 /* mptcp socket already closing? */
3604 if (!mptcp_is_fully_established(parent)) {
3605 subflow->reset_reason = MPTCP_RST_EMPTCP;
3606 return false;
3607 }
3608
3609 /* active subflow, already present inside the conn_list */
3610 if (!list_empty(&subflow->node)) {
3611 mptcp_subflow_joined(msk, ssk);
3612 mptcp_propagate_sndbuf(parent, ssk);
3613 return true;
3614 }
3615
3616 if (!mptcp_pm_allow_new_subflow(msk))
3617 goto err_prohibited;
3618
3619 /* If we can't acquire msk socket lock here, let the release callback
3620 * handle it
3621 */
3622 mptcp_data_lock(parent);
3623 if (!sock_owned_by_user(parent)) {
3624 ret = __mptcp_finish_join(msk, ssk);
3625 if (ret) {
3626 sock_hold(ssk);
3627 list_add_tail(&subflow->node, &msk->conn_list);
3628 }
3629 } else {
3630 sock_hold(ssk);
3631 list_add_tail(&subflow->node, &msk->join_list);
3632 __set_bit(MPTCP_FLUSH_JOIN_LIST, &msk->cb_flags);
3633 }
3634 mptcp_data_unlock(parent);
3635
3636 if (!ret) {
3637 err_prohibited:
3638 subflow->reset_reason = MPTCP_RST_EPROHIBIT;
3639 return false;
3640 }
3641
3642 return true;
3643 }
3644
mptcp_shutdown(struct sock * sk,int how)3645 static void mptcp_shutdown(struct sock *sk, int how)
3646 {
3647 pr_debug("sk=%p, how=%d\n", sk, how);
3648
3649 if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk))
3650 __mptcp_wr_shutdown(sk);
3651 }
3652
mptcp_forward_alloc_get(const struct sock * sk)3653 static int mptcp_forward_alloc_get(const struct sock *sk)
3654 {
3655 return READ_ONCE(sk->sk_forward_alloc) +
3656 READ_ONCE(mptcp_sk(sk)->rmem_fwd_alloc);
3657 }
3658
mptcp_ioctl_outq(const struct mptcp_sock * msk,u64 v)3659 static int mptcp_ioctl_outq(const struct mptcp_sock *msk, u64 v)
3660 {
3661 const struct sock *sk = (void *)msk;
3662 u64 delta;
3663
3664 if (sk->sk_state == TCP_LISTEN)
3665 return -EINVAL;
3666
3667 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
3668 return 0;
3669
3670 delta = msk->write_seq - v;
3671 if (__mptcp_check_fallback(msk) && msk->first) {
3672 struct tcp_sock *tp = tcp_sk(msk->first);
3673
3674 /* the first subflow is disconnected after close - see
3675 * __mptcp_close_ssk(). tcp_disconnect() moves the write_seq
3676 * so ignore that status, too.
3677 */
3678 if (!((1 << msk->first->sk_state) &
3679 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE)))
3680 delta += READ_ONCE(tp->write_seq) - tp->snd_una;
3681 }
3682 if (delta > INT_MAX)
3683 delta = INT_MAX;
3684
3685 return (int)delta;
3686 }
3687
mptcp_ioctl(struct sock * sk,int cmd,int * karg)3688 static int mptcp_ioctl(struct sock *sk, int cmd, int *karg)
3689 {
3690 struct mptcp_sock *msk = mptcp_sk(sk);
3691 bool slow;
3692
3693 switch (cmd) {
3694 case SIOCINQ:
3695 if (sk->sk_state == TCP_LISTEN)
3696 return -EINVAL;
3697
3698 lock_sock(sk);
3699 __mptcp_move_skbs(msk);
3700 *karg = mptcp_inq_hint(sk);
3701 release_sock(sk);
3702 break;
3703 case SIOCOUTQ:
3704 slow = lock_sock_fast(sk);
3705 *karg = mptcp_ioctl_outq(msk, READ_ONCE(msk->snd_una));
3706 unlock_sock_fast(sk, slow);
3707 break;
3708 case SIOCOUTQNSD:
3709 slow = lock_sock_fast(sk);
3710 *karg = mptcp_ioctl_outq(msk, msk->snd_nxt);
3711 unlock_sock_fast(sk, slow);
3712 break;
3713 default:
3714 return -ENOIOCTLCMD;
3715 }
3716
3717 return 0;
3718 }
3719
mptcp_connect(struct sock * sk,struct sockaddr * uaddr,int addr_len)3720 static int mptcp_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
3721 {
3722 struct mptcp_subflow_context *subflow;
3723 struct mptcp_sock *msk = mptcp_sk(sk);
3724 int err = -EINVAL;
3725 struct sock *ssk;
3726
3727 ssk = __mptcp_nmpc_sk(msk);
3728 if (IS_ERR(ssk))
3729 return PTR_ERR(ssk);
3730
3731 mptcp_set_state(sk, TCP_SYN_SENT);
3732 subflow = mptcp_subflow_ctx(ssk);
3733 #ifdef CONFIG_TCP_MD5SIG
3734 /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
3735 * TCP option space.
3736 */
3737 if (rcu_access_pointer(tcp_sk(ssk)->md5sig_info))
3738 mptcp_subflow_early_fallback(msk, subflow);
3739 #endif
3740 if (subflow->request_mptcp) {
3741 if (mptcp_active_should_disable(sk)) {
3742 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_MPCAPABLEACTIVEDISABLED);
3743 mptcp_subflow_early_fallback(msk, subflow);
3744 } else if (mptcp_token_new_connect(ssk) < 0) {
3745 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_TOKENFALLBACKINIT);
3746 mptcp_subflow_early_fallback(msk, subflow);
3747 }
3748 }
3749
3750 WRITE_ONCE(msk->write_seq, subflow->idsn);
3751 WRITE_ONCE(msk->snd_nxt, subflow->idsn);
3752 WRITE_ONCE(msk->snd_una, subflow->idsn);
3753 if (likely(!__mptcp_check_fallback(msk)))
3754 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVE);
3755
3756 /* if reaching here via the fastopen/sendmsg path, the caller already
3757 * acquired the subflow socket lock, too.
3758 */
3759 if (!msk->fastopening)
3760 lock_sock(ssk);
3761
3762 /* the following mirrors closely a very small chunk of code from
3763 * __inet_stream_connect()
3764 */
3765 if (ssk->sk_state != TCP_CLOSE)
3766 goto out;
3767
3768 if (BPF_CGROUP_PRE_CONNECT_ENABLED(ssk)) {
3769 err = ssk->sk_prot->pre_connect(ssk, uaddr, addr_len);
3770 if (err)
3771 goto out;
3772 }
3773
3774 err = ssk->sk_prot->connect(ssk, uaddr, addr_len);
3775 if (err < 0)
3776 goto out;
3777
3778 inet_assign_bit(DEFER_CONNECT, sk, inet_test_bit(DEFER_CONNECT, ssk));
3779
3780 out:
3781 if (!msk->fastopening)
3782 release_sock(ssk);
3783
3784 /* on successful connect, the msk state will be moved to established by
3785 * subflow_finish_connect()
3786 */
3787 if (unlikely(err)) {
3788 /* avoid leaving a dangling token in an unconnected socket */
3789 mptcp_token_destroy(msk);
3790 mptcp_set_state(sk, TCP_CLOSE);
3791 return err;
3792 }
3793
3794 mptcp_copy_inaddrs(sk, ssk);
3795 return 0;
3796 }
3797
3798 static struct proto mptcp_prot = {
3799 .name = "MPTCP",
3800 .owner = THIS_MODULE,
3801 .init = mptcp_init_sock,
3802 .connect = mptcp_connect,
3803 .disconnect = mptcp_disconnect,
3804 .close = mptcp_close,
3805 .setsockopt = mptcp_setsockopt,
3806 .getsockopt = mptcp_getsockopt,
3807 .shutdown = mptcp_shutdown,
3808 .destroy = mptcp_destroy,
3809 .sendmsg = mptcp_sendmsg,
3810 .ioctl = mptcp_ioctl,
3811 .recvmsg = mptcp_recvmsg,
3812 .release_cb = mptcp_release_cb,
3813 .hash = mptcp_hash,
3814 .unhash = mptcp_unhash,
3815 .get_port = mptcp_get_port,
3816 .forward_alloc_get = mptcp_forward_alloc_get,
3817 .stream_memory_free = mptcp_stream_memory_free,
3818 .sockets_allocated = &mptcp_sockets_allocated,
3819
3820 .memory_allocated = &tcp_memory_allocated,
3821 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc,
3822
3823 .memory_pressure = &tcp_memory_pressure,
3824 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
3825 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
3826 .sysctl_mem = sysctl_tcp_mem,
3827 .obj_size = sizeof(struct mptcp_sock),
3828 .slab_flags = SLAB_TYPESAFE_BY_RCU,
3829 .no_autobind = true,
3830 };
3831
mptcp_bind(struct socket * sock,struct sockaddr * uaddr,int addr_len)3832 static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
3833 {
3834 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3835 struct sock *ssk, *sk = sock->sk;
3836 int err = -EINVAL;
3837
3838 lock_sock(sk);
3839 ssk = __mptcp_nmpc_sk(msk);
3840 if (IS_ERR(ssk)) {
3841 err = PTR_ERR(ssk);
3842 goto unlock;
3843 }
3844
3845 if (sk->sk_family == AF_INET)
3846 err = inet_bind_sk(ssk, uaddr, addr_len);
3847 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
3848 else if (sk->sk_family == AF_INET6)
3849 err = inet6_bind_sk(ssk, uaddr, addr_len);
3850 #endif
3851 if (!err)
3852 mptcp_copy_inaddrs(sk, ssk);
3853
3854 unlock:
3855 release_sock(sk);
3856 return err;
3857 }
3858
mptcp_listen(struct socket * sock,int backlog)3859 static int mptcp_listen(struct socket *sock, int backlog)
3860 {
3861 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3862 struct sock *sk = sock->sk;
3863 struct sock *ssk;
3864 int err;
3865
3866 pr_debug("msk=%p\n", msk);
3867
3868 lock_sock(sk);
3869
3870 err = -EINVAL;
3871 if (sock->state != SS_UNCONNECTED || sock->type != SOCK_STREAM)
3872 goto unlock;
3873
3874 ssk = __mptcp_nmpc_sk(msk);
3875 if (IS_ERR(ssk)) {
3876 err = PTR_ERR(ssk);
3877 goto unlock;
3878 }
3879
3880 mptcp_set_state(sk, TCP_LISTEN);
3881 sock_set_flag(sk, SOCK_RCU_FREE);
3882
3883 lock_sock(ssk);
3884 err = __inet_listen_sk(ssk, backlog);
3885 release_sock(ssk);
3886 mptcp_set_state(sk, inet_sk_state_load(ssk));
3887
3888 if (!err) {
3889 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
3890 mptcp_copy_inaddrs(sk, ssk);
3891 mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CREATED);
3892 }
3893
3894 unlock:
3895 release_sock(sk);
3896 return err;
3897 }
3898
mptcp_stream_accept(struct socket * sock,struct socket * newsock,struct proto_accept_arg * arg)3899 static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
3900 struct proto_accept_arg *arg)
3901 {
3902 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3903 struct sock *ssk, *newsk;
3904
3905 pr_debug("msk=%p\n", msk);
3906
3907 /* Buggy applications can call accept on socket states other then LISTEN
3908 * but no need to allocate the first subflow just to error out.
3909 */
3910 ssk = READ_ONCE(msk->first);
3911 if (!ssk)
3912 return -EINVAL;
3913
3914 pr_debug("ssk=%p, listener=%p\n", ssk, mptcp_subflow_ctx(ssk));
3915 newsk = inet_csk_accept(ssk, arg);
3916 if (!newsk)
3917 return arg->err;
3918
3919 pr_debug("newsk=%p, subflow is mptcp=%d\n", newsk, sk_is_mptcp(newsk));
3920 if (sk_is_mptcp(newsk)) {
3921 struct mptcp_subflow_context *subflow;
3922 struct sock *new_mptcp_sock;
3923
3924 subflow = mptcp_subflow_ctx(newsk);
3925 new_mptcp_sock = subflow->conn;
3926
3927 /* is_mptcp should be false if subflow->conn is missing, see
3928 * subflow_syn_recv_sock()
3929 */
3930 if (WARN_ON_ONCE(!new_mptcp_sock)) {
3931 tcp_sk(newsk)->is_mptcp = 0;
3932 goto tcpfallback;
3933 }
3934
3935 newsk = new_mptcp_sock;
3936 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_MPCAPABLEPASSIVEACK);
3937
3938 newsk->sk_kern_sock = arg->kern;
3939 lock_sock(newsk);
3940 __inet_accept(sock, newsock, newsk);
3941
3942 set_bit(SOCK_CUSTOM_SOCKOPT, &newsock->flags);
3943 msk = mptcp_sk(newsk);
3944 msk->in_accept_queue = 0;
3945
3946 /* set ssk->sk_socket of accept()ed flows to mptcp socket.
3947 * This is needed so NOSPACE flag can be set from tcp stack.
3948 */
3949 mptcp_for_each_subflow(msk, subflow) {
3950 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3951
3952 if (!ssk->sk_socket)
3953 mptcp_sock_graft(ssk, newsock);
3954 }
3955
3956 /* Do late cleanup for the first subflow as necessary. Also
3957 * deal with bad peers not doing a complete shutdown.
3958 */
3959 if (unlikely(inet_sk_state_load(msk->first) == TCP_CLOSE)) {
3960 __mptcp_close_ssk(newsk, msk->first,
3961 mptcp_subflow_ctx(msk->first), 0);
3962 if (unlikely(list_is_singular(&msk->conn_list)))
3963 mptcp_set_state(newsk, TCP_CLOSE);
3964 }
3965 } else {
3966 tcpfallback:
3967 newsk->sk_kern_sock = arg->kern;
3968 lock_sock(newsk);
3969 __inet_accept(sock, newsock, newsk);
3970 /* we are being invoked after accepting a non-mp-capable
3971 * flow: sk is a tcp_sk, not an mptcp one.
3972 *
3973 * Hand the socket over to tcp so all further socket ops
3974 * bypass mptcp.
3975 */
3976 WRITE_ONCE(newsock->sk->sk_socket->ops,
3977 mptcp_fallback_tcp_ops(newsock->sk));
3978 }
3979 release_sock(newsk);
3980
3981 return 0;
3982 }
3983
mptcp_check_writeable(struct mptcp_sock * msk)3984 static __poll_t mptcp_check_writeable(struct mptcp_sock *msk)
3985 {
3986 struct sock *sk = (struct sock *)msk;
3987
3988 if (__mptcp_stream_is_writeable(sk, 1))
3989 return EPOLLOUT | EPOLLWRNORM;
3990
3991 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
3992 smp_mb__after_atomic(); /* NOSPACE is changed by mptcp_write_space() */
3993 if (__mptcp_stream_is_writeable(sk, 1))
3994 return EPOLLOUT | EPOLLWRNORM;
3995
3996 return 0;
3997 }
3998
mptcp_poll(struct file * file,struct socket * sock,struct poll_table_struct * wait)3999 static __poll_t mptcp_poll(struct file *file, struct socket *sock,
4000 struct poll_table_struct *wait)
4001 {
4002 struct sock *sk = sock->sk;
4003 struct mptcp_sock *msk;
4004 __poll_t mask = 0;
4005 u8 shutdown;
4006 int state;
4007
4008 msk = mptcp_sk(sk);
4009 sock_poll_wait(file, sock, wait);
4010
4011 state = inet_sk_state_load(sk);
4012 pr_debug("msk=%p state=%d flags=%lx\n", msk, state, msk->flags);
4013 if (state == TCP_LISTEN) {
4014 struct sock *ssk = READ_ONCE(msk->first);
4015
4016 if (WARN_ON_ONCE(!ssk))
4017 return 0;
4018
4019 return inet_csk_listen_poll(ssk);
4020 }
4021
4022 shutdown = READ_ONCE(sk->sk_shutdown);
4023 if (shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
4024 mask |= EPOLLHUP;
4025 if (shutdown & RCV_SHUTDOWN)
4026 mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
4027
4028 if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) {
4029 mask |= mptcp_check_readable(sk);
4030 if (shutdown & SEND_SHUTDOWN)
4031 mask |= EPOLLOUT | EPOLLWRNORM;
4032 else
4033 mask |= mptcp_check_writeable(msk);
4034 } else if (state == TCP_SYN_SENT &&
4035 inet_test_bit(DEFER_CONNECT, sk)) {
4036 /* cf tcp_poll() note about TFO */
4037 mask |= EPOLLOUT | EPOLLWRNORM;
4038 }
4039
4040 /* This barrier is coupled with smp_wmb() in __mptcp_error_report() */
4041 smp_rmb();
4042 if (READ_ONCE(sk->sk_err))
4043 mask |= EPOLLERR;
4044
4045 return mask;
4046 }
4047
4048 static const struct proto_ops mptcp_stream_ops = {
4049 .family = PF_INET,
4050 .owner = THIS_MODULE,
4051 .release = inet_release,
4052 .bind = mptcp_bind,
4053 .connect = inet_stream_connect,
4054 .socketpair = sock_no_socketpair,
4055 .accept = mptcp_stream_accept,
4056 .getname = inet_getname,
4057 .poll = mptcp_poll,
4058 .ioctl = inet_ioctl,
4059 .gettstamp = sock_gettstamp,
4060 .listen = mptcp_listen,
4061 .shutdown = inet_shutdown,
4062 .setsockopt = sock_common_setsockopt,
4063 .getsockopt = sock_common_getsockopt,
4064 .sendmsg = inet_sendmsg,
4065 .recvmsg = inet_recvmsg,
4066 .mmap = sock_no_mmap,
4067 .set_rcvlowat = mptcp_set_rcvlowat,
4068 };
4069
4070 static struct inet_protosw mptcp_protosw = {
4071 .type = SOCK_STREAM,
4072 .protocol = IPPROTO_MPTCP,
4073 .prot = &mptcp_prot,
4074 .ops = &mptcp_stream_ops,
4075 .flags = INET_PROTOSW_ICSK,
4076 };
4077
mptcp_napi_poll(struct napi_struct * napi,int budget)4078 static int mptcp_napi_poll(struct napi_struct *napi, int budget)
4079 {
4080 struct mptcp_delegated_action *delegated;
4081 struct mptcp_subflow_context *subflow;
4082 int work_done = 0;
4083
4084 delegated = container_of(napi, struct mptcp_delegated_action, napi);
4085 while ((subflow = mptcp_subflow_delegated_next(delegated)) != NULL) {
4086 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
4087
4088 bh_lock_sock_nested(ssk);
4089 if (!sock_owned_by_user(ssk)) {
4090 mptcp_subflow_process_delegated(ssk, xchg(&subflow->delegated_status, 0));
4091 } else {
4092 /* tcp_release_cb_override already processed
4093 * the action or will do at next release_sock().
4094 * In both case must dequeue the subflow here - on the same
4095 * CPU that scheduled it.
4096 */
4097 smp_wmb();
4098 clear_bit(MPTCP_DELEGATE_SCHEDULED, &subflow->delegated_status);
4099 }
4100 bh_unlock_sock(ssk);
4101 sock_put(ssk);
4102
4103 if (++work_done == budget)
4104 return budget;
4105 }
4106
4107 /* always provide a 0 'work_done' argument, so that napi_complete_done
4108 * will not try accessing the NULL napi->dev ptr
4109 */
4110 napi_complete_done(napi, 0);
4111 return work_done;
4112 }
4113
mptcp_proto_init(void)4114 void __init mptcp_proto_init(void)
4115 {
4116 struct mptcp_delegated_action *delegated;
4117 int cpu;
4118
4119 mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo;
4120
4121 if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL))
4122 panic("Failed to allocate MPTCP pcpu counter\n");
4123
4124 init_dummy_netdev(&mptcp_napi_dev);
4125 for_each_possible_cpu(cpu) {
4126 delegated = per_cpu_ptr(&mptcp_delegated_actions, cpu);
4127 INIT_LIST_HEAD(&delegated->head);
4128 netif_napi_add_tx(&mptcp_napi_dev, &delegated->napi,
4129 mptcp_napi_poll);
4130 napi_enable(&delegated->napi);
4131 }
4132
4133 mptcp_subflow_init();
4134 mptcp_pm_init();
4135 mptcp_sched_init();
4136 mptcp_token_init();
4137
4138 if (proto_register(&mptcp_prot, 1) != 0)
4139 panic("Failed to register MPTCP proto.\n");
4140
4141 inet_register_protosw(&mptcp_protosw);
4142
4143 BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb));
4144 }
4145
4146 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
4147 static const struct proto_ops mptcp_v6_stream_ops = {
4148 .family = PF_INET6,
4149 .owner = THIS_MODULE,
4150 .release = inet6_release,
4151 .bind = mptcp_bind,
4152 .connect = inet_stream_connect,
4153 .socketpair = sock_no_socketpair,
4154 .accept = mptcp_stream_accept,
4155 .getname = inet6_getname,
4156 .poll = mptcp_poll,
4157 .ioctl = inet6_ioctl,
4158 .gettstamp = sock_gettstamp,
4159 .listen = mptcp_listen,
4160 .shutdown = inet_shutdown,
4161 .setsockopt = sock_common_setsockopt,
4162 .getsockopt = sock_common_getsockopt,
4163 .sendmsg = inet6_sendmsg,
4164 .recvmsg = inet6_recvmsg,
4165 .mmap = sock_no_mmap,
4166 #ifdef CONFIG_COMPAT
4167 .compat_ioctl = inet6_compat_ioctl,
4168 #endif
4169 .set_rcvlowat = mptcp_set_rcvlowat,
4170 };
4171
4172 static struct proto mptcp_v6_prot;
4173
4174 static struct inet_protosw mptcp_v6_protosw = {
4175 .type = SOCK_STREAM,
4176 .protocol = IPPROTO_MPTCP,
4177 .prot = &mptcp_v6_prot,
4178 .ops = &mptcp_v6_stream_ops,
4179 .flags = INET_PROTOSW_ICSK,
4180 };
4181
mptcp_proto_v6_init(void)4182 int __init mptcp_proto_v6_init(void)
4183 {
4184 int err;
4185
4186 mptcp_v6_prot = mptcp_prot;
4187 strscpy(mptcp_v6_prot.name, "MPTCPv6", sizeof(mptcp_v6_prot.name));
4188 mptcp_v6_prot.slab = NULL;
4189 mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock);
4190 mptcp_v6_prot.ipv6_pinfo_offset = offsetof(struct mptcp6_sock, np);
4191
4192 err = proto_register(&mptcp_v6_prot, 1);
4193 if (err)
4194 return err;
4195
4196 err = inet6_register_protosw(&mptcp_v6_protosw);
4197 if (err)
4198 proto_unregister(&mptcp_v6_prot);
4199
4200 return err;
4201 }
4202 #endif
4203