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 ((to->len + from->len) > (sk->sk_rcvbuf >> 3)) ||
140 !skb_try_coalesce(to, from, &fragstolen, &delta))
141 return false;
142
143 pr_debug("colesced seq %llx into %llx new len %d new end seq %llx\n",
144 MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq,
145 to->len, MPTCP_SKB_CB(from)->end_seq);
146 MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq;
147
148 /* note the fwd memory can reach a negative value after accounting
149 * for the delta, but the later skb free will restore a non
150 * negative one
151 */
152 atomic_add(delta, &sk->sk_rmem_alloc);
153 mptcp_rmem_charge(sk, delta);
154 kfree_skb_partial(from, fragstolen);
155
156 return true;
157 }
158
mptcp_ooo_try_coalesce(struct mptcp_sock * msk,struct sk_buff * to,struct sk_buff * from)159 static bool mptcp_ooo_try_coalesce(struct mptcp_sock *msk, struct sk_buff *to,
160 struct sk_buff *from)
161 {
162 if (MPTCP_SKB_CB(from)->map_seq != MPTCP_SKB_CB(to)->end_seq)
163 return false;
164
165 return mptcp_try_coalesce((struct sock *)msk, to, from);
166 }
167
__mptcp_rmem_reclaim(struct sock * sk,int amount)168 static void __mptcp_rmem_reclaim(struct sock *sk, int amount)
169 {
170 amount >>= PAGE_SHIFT;
171 mptcp_rmem_charge(sk, amount << PAGE_SHIFT);
172 __sk_mem_reduce_allocated(sk, amount);
173 }
174
mptcp_rmem_uncharge(struct sock * sk,int size)175 static void mptcp_rmem_uncharge(struct sock *sk, int size)
176 {
177 struct mptcp_sock *msk = mptcp_sk(sk);
178 int reclaimable;
179
180 mptcp_rmem_fwd_alloc_add(sk, size);
181 reclaimable = msk->rmem_fwd_alloc - sk_unused_reserved_mem(sk);
182
183 /* see sk_mem_uncharge() for the rationale behind the following schema */
184 if (unlikely(reclaimable >= PAGE_SIZE))
185 __mptcp_rmem_reclaim(sk, reclaimable);
186 }
187
mptcp_rfree(struct sk_buff * skb)188 static void mptcp_rfree(struct sk_buff *skb)
189 {
190 unsigned int len = skb->truesize;
191 struct sock *sk = skb->sk;
192
193 atomic_sub(len, &sk->sk_rmem_alloc);
194 mptcp_rmem_uncharge(sk, len);
195 }
196
mptcp_set_owner_r(struct sk_buff * skb,struct sock * sk)197 void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk)
198 {
199 skb_orphan(skb);
200 skb->sk = sk;
201 skb->destructor = mptcp_rfree;
202 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
203 mptcp_rmem_charge(sk, skb->truesize);
204 }
205
206 /* "inspired" by tcp_data_queue_ofo(), main differences:
207 * - use mptcp seqs
208 * - don't cope with sacks
209 */
mptcp_data_queue_ofo(struct mptcp_sock * msk,struct sk_buff * skb)210 static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb)
211 {
212 struct sock *sk = (struct sock *)msk;
213 struct rb_node **p, *parent;
214 u64 seq, end_seq, max_seq;
215 struct sk_buff *skb1;
216
217 seq = MPTCP_SKB_CB(skb)->map_seq;
218 end_seq = MPTCP_SKB_CB(skb)->end_seq;
219 max_seq = atomic64_read(&msk->rcv_wnd_sent);
220
221 pr_debug("msk=%p seq=%llx limit=%llx empty=%d\n", msk, seq, max_seq,
222 RB_EMPTY_ROOT(&msk->out_of_order_queue));
223 if (after64(end_seq, max_seq)) {
224 /* out of window */
225 mptcp_drop(sk, skb);
226 pr_debug("oow by %lld, rcv_wnd_sent %llu\n",
227 (unsigned long long)end_seq - (unsigned long)max_seq,
228 (unsigned long long)atomic64_read(&msk->rcv_wnd_sent));
229 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_NODSSWINDOW);
230 return;
231 }
232
233 p = &msk->out_of_order_queue.rb_node;
234 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUE);
235 if (RB_EMPTY_ROOT(&msk->out_of_order_queue)) {
236 rb_link_node(&skb->rbnode, NULL, p);
237 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
238 msk->ooo_last_skb = skb;
239 goto end;
240 }
241
242 /* with 2 subflows, adding at end of ooo queue is quite likely
243 * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup.
244 */
245 if (mptcp_ooo_try_coalesce(msk, msk->ooo_last_skb, skb)) {
246 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
247 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
248 return;
249 }
250
251 /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */
252 if (!before64(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) {
253 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
254 parent = &msk->ooo_last_skb->rbnode;
255 p = &parent->rb_right;
256 goto insert;
257 }
258
259 /* Find place to insert this segment. Handle overlaps on the way. */
260 parent = NULL;
261 while (*p) {
262 parent = *p;
263 skb1 = rb_to_skb(parent);
264 if (before64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
265 p = &parent->rb_left;
266 continue;
267 }
268 if (before64(seq, MPTCP_SKB_CB(skb1)->end_seq)) {
269 if (!after64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) {
270 /* All the bits are present. Drop. */
271 mptcp_drop(sk, skb);
272 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
273 return;
274 }
275 if (after64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
276 /* partial overlap:
277 * | skb |
278 * | skb1 |
279 * continue traversing
280 */
281 } else {
282 /* skb's seq == skb1's seq and skb covers skb1.
283 * Replace skb1 with skb.
284 */
285 rb_replace_node(&skb1->rbnode, &skb->rbnode,
286 &msk->out_of_order_queue);
287 mptcp_drop(sk, skb1);
288 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
289 goto merge_right;
290 }
291 } else if (mptcp_ooo_try_coalesce(msk, skb1, skb)) {
292 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
293 return;
294 }
295 p = &parent->rb_right;
296 }
297
298 insert:
299 /* Insert segment into RB tree. */
300 rb_link_node(&skb->rbnode, parent, p);
301 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
302
303 merge_right:
304 /* Remove other segments covered by skb. */
305 while ((skb1 = skb_rb_next(skb)) != NULL) {
306 if (before64(end_seq, MPTCP_SKB_CB(skb1)->end_seq))
307 break;
308 rb_erase(&skb1->rbnode, &msk->out_of_order_queue);
309 mptcp_drop(sk, skb1);
310 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
311 }
312 /* If there is no skb after us, we are the last_skb ! */
313 if (!skb1)
314 msk->ooo_last_skb = skb;
315
316 end:
317 skb_condense(skb);
318 mptcp_set_owner_r(skb, sk);
319 }
320
mptcp_rmem_schedule(struct sock * sk,struct sock * ssk,int size)321 static bool mptcp_rmem_schedule(struct sock *sk, struct sock *ssk, int size)
322 {
323 struct mptcp_sock *msk = mptcp_sk(sk);
324 int amt, amount;
325
326 if (size <= msk->rmem_fwd_alloc)
327 return true;
328
329 size -= msk->rmem_fwd_alloc;
330 amt = sk_mem_pages(size);
331 amount = amt << PAGE_SHIFT;
332 if (!__sk_mem_raise_allocated(sk, size, amt, SK_MEM_RECV))
333 return false;
334
335 mptcp_rmem_fwd_alloc_add(sk, amount);
336 return true;
337 }
338
__mptcp_move_skb(struct mptcp_sock * msk,struct sock * ssk,struct sk_buff * skb,unsigned int offset,size_t copy_len)339 static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk,
340 struct sk_buff *skb, unsigned int offset,
341 size_t copy_len)
342 {
343 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
344 struct sock *sk = (struct sock *)msk;
345 struct sk_buff *tail;
346 bool has_rxtstamp;
347
348 __skb_unlink(skb, &ssk->sk_receive_queue);
349
350 skb_ext_reset(skb);
351 skb_orphan(skb);
352
353 /* try to fetch required memory from subflow */
354 if (!mptcp_rmem_schedule(sk, ssk, skb->truesize)) {
355 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED);
356 goto drop;
357 }
358
359 has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp;
360
361 /* the skb map_seq accounts for the skb offset:
362 * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq
363 * value
364 */
365 MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow);
366 MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len;
367 MPTCP_SKB_CB(skb)->offset = offset;
368 MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp;
369
370 if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) {
371 /* in sequence */
372 msk->bytes_received += copy_len;
373 WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len);
374 tail = skb_peek_tail(&sk->sk_receive_queue);
375 if (tail && mptcp_try_coalesce(sk, tail, skb))
376 return true;
377
378 mptcp_set_owner_r(skb, sk);
379 __skb_queue_tail(&sk->sk_receive_queue, skb);
380 return true;
381 } else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) {
382 mptcp_data_queue_ofo(msk, skb);
383 return false;
384 }
385
386 /* old data, keep it simple and drop the whole pkt, sender
387 * will retransmit as needed, if needed.
388 */
389 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
390 drop:
391 mptcp_drop(sk, skb);
392 return false;
393 }
394
mptcp_stop_rtx_timer(struct sock * sk)395 static void mptcp_stop_rtx_timer(struct sock *sk)
396 {
397 struct inet_connection_sock *icsk = inet_csk(sk);
398
399 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
400 mptcp_sk(sk)->timer_ival = 0;
401 }
402
mptcp_close_wake_up(struct sock * sk)403 static void mptcp_close_wake_up(struct sock *sk)
404 {
405 if (sock_flag(sk, SOCK_DEAD))
406 return;
407
408 sk->sk_state_change(sk);
409 if (sk->sk_shutdown == SHUTDOWN_MASK ||
410 sk->sk_state == TCP_CLOSE)
411 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
412 else
413 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
414 }
415
416 /* called under the msk socket lock */
mptcp_pending_data_fin_ack(struct sock * sk)417 static bool mptcp_pending_data_fin_ack(struct sock *sk)
418 {
419 struct mptcp_sock *msk = mptcp_sk(sk);
420
421 return ((1 << sk->sk_state) &
422 (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) &&
423 msk->write_seq == READ_ONCE(msk->snd_una);
424 }
425
mptcp_check_data_fin_ack(struct sock * sk)426 static void mptcp_check_data_fin_ack(struct sock *sk)
427 {
428 struct mptcp_sock *msk = mptcp_sk(sk);
429
430 /* Look for an acknowledged DATA_FIN */
431 if (mptcp_pending_data_fin_ack(sk)) {
432 WRITE_ONCE(msk->snd_data_fin_enable, 0);
433
434 switch (sk->sk_state) {
435 case TCP_FIN_WAIT1:
436 mptcp_set_state(sk, TCP_FIN_WAIT2);
437 break;
438 case TCP_CLOSING:
439 case TCP_LAST_ACK:
440 mptcp_set_state(sk, TCP_CLOSE);
441 break;
442 }
443
444 mptcp_close_wake_up(sk);
445 }
446 }
447
448 /* can be called with no lock acquired */
mptcp_pending_data_fin(struct sock * sk,u64 * seq)449 static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq)
450 {
451 struct mptcp_sock *msk = mptcp_sk(sk);
452
453 if (READ_ONCE(msk->rcv_data_fin) &&
454 ((1 << inet_sk_state_load(sk)) &
455 (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) {
456 u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq);
457
458 if (READ_ONCE(msk->ack_seq) == rcv_data_fin_seq) {
459 if (seq)
460 *seq = rcv_data_fin_seq;
461
462 return true;
463 }
464 }
465
466 return false;
467 }
468
mptcp_set_datafin_timeout(struct sock * sk)469 static void mptcp_set_datafin_timeout(struct sock *sk)
470 {
471 struct inet_connection_sock *icsk = inet_csk(sk);
472 u32 retransmits;
473
474 retransmits = min_t(u32, icsk->icsk_retransmits,
475 ilog2(TCP_RTO_MAX / TCP_RTO_MIN));
476
477 mptcp_sk(sk)->timer_ival = TCP_RTO_MIN << retransmits;
478 }
479
__mptcp_set_timeout(struct sock * sk,long tout)480 static void __mptcp_set_timeout(struct sock *sk, long tout)
481 {
482 mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
483 }
484
mptcp_timeout_from_subflow(const struct mptcp_subflow_context * subflow)485 static long mptcp_timeout_from_subflow(const struct mptcp_subflow_context *subflow)
486 {
487 const struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
488
489 return inet_csk(ssk)->icsk_pending && !subflow->stale_count ?
490 inet_csk(ssk)->icsk_timeout - jiffies : 0;
491 }
492
mptcp_set_timeout(struct sock * sk)493 static void mptcp_set_timeout(struct sock *sk)
494 {
495 struct mptcp_subflow_context *subflow;
496 long tout = 0;
497
498 mptcp_for_each_subflow(mptcp_sk(sk), subflow)
499 tout = max(tout, mptcp_timeout_from_subflow(subflow));
500 __mptcp_set_timeout(sk, tout);
501 }
502
tcp_can_send_ack(const struct sock * ssk)503 static inline bool tcp_can_send_ack(const struct sock *ssk)
504 {
505 return !((1 << inet_sk_state_load(ssk)) &
506 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE | TCPF_LISTEN));
507 }
508
__mptcp_subflow_send_ack(struct sock * ssk)509 void __mptcp_subflow_send_ack(struct sock *ssk)
510 {
511 if (tcp_can_send_ack(ssk))
512 tcp_send_ack(ssk);
513 }
514
mptcp_subflow_send_ack(struct sock * ssk)515 static void mptcp_subflow_send_ack(struct sock *ssk)
516 {
517 bool slow;
518
519 slow = lock_sock_fast(ssk);
520 __mptcp_subflow_send_ack(ssk);
521 unlock_sock_fast(ssk, slow);
522 }
523
mptcp_send_ack(struct mptcp_sock * msk)524 static void mptcp_send_ack(struct mptcp_sock *msk)
525 {
526 struct mptcp_subflow_context *subflow;
527
528 mptcp_for_each_subflow(msk, subflow)
529 mptcp_subflow_send_ack(mptcp_subflow_tcp_sock(subflow));
530 }
531
mptcp_subflow_cleanup_rbuf(struct sock * ssk,int copied)532 static void mptcp_subflow_cleanup_rbuf(struct sock *ssk, int copied)
533 {
534 bool slow;
535
536 slow = lock_sock_fast(ssk);
537 if (tcp_can_send_ack(ssk))
538 tcp_cleanup_rbuf(ssk, copied);
539 unlock_sock_fast(ssk, slow);
540 }
541
mptcp_subflow_could_cleanup(const struct sock * ssk,bool rx_empty)542 static bool mptcp_subflow_could_cleanup(const struct sock *ssk, bool rx_empty)
543 {
544 const struct inet_connection_sock *icsk = inet_csk(ssk);
545 u8 ack_pending = READ_ONCE(icsk->icsk_ack.pending);
546 const struct tcp_sock *tp = tcp_sk(ssk);
547
548 return (ack_pending & ICSK_ACK_SCHED) &&
549 ((READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->rcv_wup) >
550 READ_ONCE(icsk->icsk_ack.rcv_mss)) ||
551 (rx_empty && ack_pending &
552 (ICSK_ACK_PUSHED2 | ICSK_ACK_PUSHED)));
553 }
554
mptcp_cleanup_rbuf(struct mptcp_sock * msk,int copied)555 static void mptcp_cleanup_rbuf(struct mptcp_sock *msk, int copied)
556 {
557 int old_space = READ_ONCE(msk->old_wspace);
558 struct mptcp_subflow_context *subflow;
559 struct sock *sk = (struct sock *)msk;
560 int space = __mptcp_space(sk);
561 bool cleanup, rx_empty;
562
563 cleanup = (space > 0) && (space >= (old_space << 1)) && copied;
564 rx_empty = !__mptcp_rmem(sk) && copied;
565
566 mptcp_for_each_subflow(msk, subflow) {
567 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
568
569 if (cleanup || mptcp_subflow_could_cleanup(ssk, rx_empty))
570 mptcp_subflow_cleanup_rbuf(ssk, copied);
571 }
572 }
573
mptcp_check_data_fin(struct sock * sk)574 static bool mptcp_check_data_fin(struct sock *sk)
575 {
576 struct mptcp_sock *msk = mptcp_sk(sk);
577 u64 rcv_data_fin_seq;
578 bool ret = false;
579
580 /* Need to ack a DATA_FIN received from a peer while this side
581 * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2.
582 * msk->rcv_data_fin was set when parsing the incoming options
583 * at the subflow level and the msk lock was not held, so this
584 * is the first opportunity to act on the DATA_FIN and change
585 * the msk state.
586 *
587 * If we are caught up to the sequence number of the incoming
588 * DATA_FIN, send the DATA_ACK now and do state transition. If
589 * not caught up, do nothing and let the recv code send DATA_ACK
590 * when catching up.
591 */
592
593 if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) {
594 WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1);
595 WRITE_ONCE(msk->rcv_data_fin, 0);
596
597 WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | RCV_SHUTDOWN);
598 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
599
600 switch (sk->sk_state) {
601 case TCP_ESTABLISHED:
602 mptcp_set_state(sk, TCP_CLOSE_WAIT);
603 break;
604 case TCP_FIN_WAIT1:
605 mptcp_set_state(sk, TCP_CLOSING);
606 break;
607 case TCP_FIN_WAIT2:
608 mptcp_set_state(sk, TCP_CLOSE);
609 break;
610 default:
611 /* Other states not expected */
612 WARN_ON_ONCE(1);
613 break;
614 }
615
616 ret = true;
617 if (!__mptcp_check_fallback(msk))
618 mptcp_send_ack(msk);
619 mptcp_close_wake_up(sk);
620 }
621 return ret;
622 }
623
mptcp_dss_corruption(struct mptcp_sock * msk,struct sock * ssk)624 static void mptcp_dss_corruption(struct mptcp_sock *msk, struct sock *ssk)
625 {
626 if (READ_ONCE(msk->allow_infinite_fallback)) {
627 MPTCP_INC_STATS(sock_net(ssk),
628 MPTCP_MIB_DSSCORRUPTIONFALLBACK);
629 mptcp_do_fallback(ssk);
630 } else {
631 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DSSCORRUPTIONRESET);
632 mptcp_subflow_reset(ssk);
633 }
634 }
635
__mptcp_move_skbs_from_subflow(struct mptcp_sock * msk,struct sock * ssk,unsigned int * bytes)636 static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
637 struct sock *ssk,
638 unsigned int *bytes)
639 {
640 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
641 struct sock *sk = (struct sock *)msk;
642 unsigned int moved = 0;
643 bool more_data_avail;
644 struct tcp_sock *tp;
645 bool done = false;
646 int sk_rbuf;
647
648 sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
649
650 if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
651 int ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
652
653 if (unlikely(ssk_rbuf > sk_rbuf)) {
654 WRITE_ONCE(sk->sk_rcvbuf, ssk_rbuf);
655 sk_rbuf = ssk_rbuf;
656 }
657 }
658
659 pr_debug("msk=%p ssk=%p\n", msk, ssk);
660 tp = tcp_sk(ssk);
661 do {
662 u32 map_remaining, offset;
663 u32 seq = tp->copied_seq;
664 struct sk_buff *skb;
665 bool fin;
666
667 /* try to move as much data as available */
668 map_remaining = subflow->map_data_len -
669 mptcp_subflow_get_map_offset(subflow);
670
671 skb = skb_peek(&ssk->sk_receive_queue);
672 if (!skb) {
673 /* With racing move_skbs_to_msk() and __mptcp_move_skbs(),
674 * a different CPU can have already processed the pending
675 * data, stop here or we can enter an infinite loop
676 */
677 if (!moved)
678 done = true;
679 break;
680 }
681
682 if (__mptcp_check_fallback(msk)) {
683 /* Under fallback skbs have no MPTCP extension and TCP could
684 * collapse them between the dummy map creation and the
685 * current dequeue. Be sure to adjust the map size.
686 */
687 map_remaining = skb->len;
688 subflow->map_data_len = skb->len;
689 }
690
691 offset = seq - TCP_SKB_CB(skb)->seq;
692 fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
693 if (fin) {
694 done = true;
695 seq++;
696 }
697
698 if (offset < skb->len) {
699 size_t len = skb->len - offset;
700
701 if (tp->urg_data)
702 done = true;
703
704 if (__mptcp_move_skb(msk, ssk, skb, offset, len))
705 moved += len;
706 seq += len;
707
708 if (unlikely(map_remaining < len)) {
709 DEBUG_NET_WARN_ON_ONCE(1);
710 mptcp_dss_corruption(msk, ssk);
711 }
712 } else {
713 if (unlikely(!fin)) {
714 DEBUG_NET_WARN_ON_ONCE(1);
715 mptcp_dss_corruption(msk, ssk);
716 }
717
718 sk_eat_skb(ssk, skb);
719 done = true;
720 }
721
722 WRITE_ONCE(tp->copied_seq, seq);
723 more_data_avail = mptcp_subflow_data_available(ssk);
724
725 if (atomic_read(&sk->sk_rmem_alloc) > sk_rbuf) {
726 done = true;
727 break;
728 }
729 } while (more_data_avail);
730
731 if (moved > 0)
732 msk->last_data_recv = tcp_jiffies32;
733 *bytes += moved;
734 return done;
735 }
736
__mptcp_ofo_queue(struct mptcp_sock * msk)737 static bool __mptcp_ofo_queue(struct mptcp_sock *msk)
738 {
739 struct sock *sk = (struct sock *)msk;
740 struct sk_buff *skb, *tail;
741 bool moved = false;
742 struct rb_node *p;
743 u64 end_seq;
744
745 p = rb_first(&msk->out_of_order_queue);
746 pr_debug("msk=%p empty=%d\n", msk, RB_EMPTY_ROOT(&msk->out_of_order_queue));
747 while (p) {
748 skb = rb_to_skb(p);
749 if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq))
750 break;
751
752 p = rb_next(p);
753 rb_erase(&skb->rbnode, &msk->out_of_order_queue);
754
755 if (unlikely(!after64(MPTCP_SKB_CB(skb)->end_seq,
756 msk->ack_seq))) {
757 mptcp_drop(sk, skb);
758 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
759 continue;
760 }
761
762 end_seq = MPTCP_SKB_CB(skb)->end_seq;
763 tail = skb_peek_tail(&sk->sk_receive_queue);
764 if (!tail || !mptcp_ooo_try_coalesce(msk, tail, skb)) {
765 int delta = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq;
766
767 /* skip overlapping data, if any */
768 pr_debug("uncoalesced seq=%llx ack seq=%llx delta=%d\n",
769 MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq,
770 delta);
771 MPTCP_SKB_CB(skb)->offset += delta;
772 MPTCP_SKB_CB(skb)->map_seq += delta;
773 __skb_queue_tail(&sk->sk_receive_queue, skb);
774 }
775 msk->bytes_received += end_seq - msk->ack_seq;
776 WRITE_ONCE(msk->ack_seq, end_seq);
777 moved = true;
778 }
779 return moved;
780 }
781
__mptcp_subflow_error_report(struct sock * sk,struct sock * ssk)782 static bool __mptcp_subflow_error_report(struct sock *sk, struct sock *ssk)
783 {
784 int err = sock_error(ssk);
785 int ssk_state;
786
787 if (!err)
788 return false;
789
790 /* only propagate errors on fallen-back sockets or
791 * on MPC connect
792 */
793 if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(mptcp_sk(sk)))
794 return false;
795
796 /* We need to propagate only transition to CLOSE state.
797 * Orphaned socket will see such state change via
798 * subflow_sched_work_if_closed() and that path will properly
799 * destroy the msk as needed.
800 */
801 ssk_state = inet_sk_state_load(ssk);
802 if (ssk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DEAD))
803 mptcp_set_state(sk, ssk_state);
804 WRITE_ONCE(sk->sk_err, -err);
805
806 /* This barrier is coupled with smp_rmb() in mptcp_poll() */
807 smp_wmb();
808 sk_error_report(sk);
809 return true;
810 }
811
__mptcp_error_report(struct sock * sk)812 void __mptcp_error_report(struct sock *sk)
813 {
814 struct mptcp_subflow_context *subflow;
815 struct mptcp_sock *msk = mptcp_sk(sk);
816
817 mptcp_for_each_subflow(msk, subflow)
818 if (__mptcp_subflow_error_report(sk, mptcp_subflow_tcp_sock(subflow)))
819 break;
820 }
821
822 /* In most cases we will be able to lock the mptcp socket. If its already
823 * owned, we need to defer to the work queue to avoid ABBA deadlock.
824 */
move_skbs_to_msk(struct mptcp_sock * msk,struct sock * ssk)825 static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk)
826 {
827 struct sock *sk = (struct sock *)msk;
828 unsigned int moved = 0;
829
830 __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
831 __mptcp_ofo_queue(msk);
832 if (unlikely(ssk->sk_err)) {
833 if (!sock_owned_by_user(sk))
834 __mptcp_error_report(sk);
835 else
836 __set_bit(MPTCP_ERROR_REPORT, &msk->cb_flags);
837 }
838
839 /* If the moves have caught up with the DATA_FIN sequence number
840 * it's time to ack the DATA_FIN and change socket state, but
841 * this is not a good place to change state. Let the workqueue
842 * do it.
843 */
844 if (mptcp_pending_data_fin(sk, NULL))
845 mptcp_schedule_work(sk);
846 return moved > 0;
847 }
848
mptcp_data_ready(struct sock * sk,struct sock * ssk)849 void mptcp_data_ready(struct sock *sk, struct sock *ssk)
850 {
851 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
852 struct mptcp_sock *msk = mptcp_sk(sk);
853 int sk_rbuf, ssk_rbuf;
854
855 /* The peer can send data while we are shutting down this
856 * subflow at msk destruction time, but we must avoid enqueuing
857 * more data to the msk receive queue
858 */
859 if (unlikely(subflow->disposable))
860 return;
861
862 ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
863 sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
864 if (unlikely(ssk_rbuf > sk_rbuf))
865 sk_rbuf = ssk_rbuf;
866
867 /* over limit? can't append more skbs to msk, Also, no need to wake-up*/
868 if (__mptcp_rmem(sk) > sk_rbuf)
869 return;
870
871 /* Wake-up the reader only for in-sequence data */
872 mptcp_data_lock(sk);
873 if (move_skbs_to_msk(msk, ssk) && mptcp_epollin_ready(sk))
874 sk->sk_data_ready(sk);
875 mptcp_data_unlock(sk);
876 }
877
mptcp_subflow_joined(struct mptcp_sock * msk,struct sock * ssk)878 static void mptcp_subflow_joined(struct mptcp_sock *msk, struct sock *ssk)
879 {
880 mptcp_subflow_ctx(ssk)->map_seq = READ_ONCE(msk->ack_seq);
881 WRITE_ONCE(msk->allow_infinite_fallback, false);
882 mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC);
883 }
884
__mptcp_finish_join(struct mptcp_sock * msk,struct sock * ssk)885 static bool __mptcp_finish_join(struct mptcp_sock *msk, struct sock *ssk)
886 {
887 struct sock *sk = (struct sock *)msk;
888
889 if (sk->sk_state != TCP_ESTABLISHED)
890 return false;
891
892 /* attach to msk socket only after we are sure we will deal with it
893 * at close time
894 */
895 if (sk->sk_socket && !ssk->sk_socket)
896 mptcp_sock_graft(ssk, sk->sk_socket);
897
898 mptcp_subflow_ctx(ssk)->subflow_id = msk->subflow_id++;
899 mptcp_sockopt_sync_locked(msk, ssk);
900 mptcp_subflow_joined(msk, ssk);
901 mptcp_stop_tout_timer(sk);
902 __mptcp_propagate_sndbuf(sk, ssk);
903 return true;
904 }
905
__mptcp_flush_join_list(struct sock * sk,struct list_head * join_list)906 static void __mptcp_flush_join_list(struct sock *sk, struct list_head *join_list)
907 {
908 struct mptcp_subflow_context *tmp, *subflow;
909 struct mptcp_sock *msk = mptcp_sk(sk);
910
911 list_for_each_entry_safe(subflow, tmp, join_list, node) {
912 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
913 bool slow = lock_sock_fast(ssk);
914
915 list_move_tail(&subflow->node, &msk->conn_list);
916 if (!__mptcp_finish_join(msk, ssk))
917 mptcp_subflow_reset(ssk);
918 unlock_sock_fast(ssk, slow);
919 }
920 }
921
mptcp_rtx_timer_pending(struct sock * sk)922 static bool mptcp_rtx_timer_pending(struct sock *sk)
923 {
924 return timer_pending(&inet_csk(sk)->icsk_retransmit_timer);
925 }
926
mptcp_reset_rtx_timer(struct sock * sk)927 static void mptcp_reset_rtx_timer(struct sock *sk)
928 {
929 struct inet_connection_sock *icsk = inet_csk(sk);
930 unsigned long tout;
931
932 /* prevent rescheduling on close */
933 if (unlikely(inet_sk_state_load(sk) == TCP_CLOSE))
934 return;
935
936 tout = mptcp_sk(sk)->timer_ival;
937 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout);
938 }
939
mptcp_schedule_work(struct sock * sk)940 bool mptcp_schedule_work(struct sock *sk)
941 {
942 if (inet_sk_state_load(sk) != TCP_CLOSE &&
943 schedule_work(&mptcp_sk(sk)->work)) {
944 /* each subflow already holds a reference to the sk, and the
945 * workqueue is invoked by a subflow, so sk can't go away here.
946 */
947 sock_hold(sk);
948 return true;
949 }
950 return false;
951 }
952
mptcp_subflow_recv_lookup(const struct mptcp_sock * msk)953 static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk)
954 {
955 struct mptcp_subflow_context *subflow;
956
957 msk_owned_by_me(msk);
958
959 mptcp_for_each_subflow(msk, subflow) {
960 if (READ_ONCE(subflow->data_avail))
961 return mptcp_subflow_tcp_sock(subflow);
962 }
963
964 return NULL;
965 }
966
mptcp_skb_can_collapse_to(u64 write_seq,const struct sk_buff * skb,const struct mptcp_ext * mpext)967 static bool mptcp_skb_can_collapse_to(u64 write_seq,
968 const struct sk_buff *skb,
969 const struct mptcp_ext *mpext)
970 {
971 if (!tcp_skb_can_collapse_to(skb))
972 return false;
973
974 /* can collapse only if MPTCP level sequence is in order and this
975 * mapping has not been xmitted yet
976 */
977 return mpext && mpext->data_seq + mpext->data_len == write_seq &&
978 !mpext->frozen;
979 }
980
981 /* we can append data to the given data frag if:
982 * - there is space available in the backing page_frag
983 * - the data frag tail matches the current page_frag free offset
984 * - the data frag end sequence number matches the current write seq
985 */
mptcp_frag_can_collapse_to(const struct mptcp_sock * msk,const struct page_frag * pfrag,const struct mptcp_data_frag * df)986 static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk,
987 const struct page_frag *pfrag,
988 const struct mptcp_data_frag *df)
989 {
990 return df && pfrag->page == df->page &&
991 pfrag->size - pfrag->offset > 0 &&
992 pfrag->offset == (df->offset + df->data_len) &&
993 df->data_seq + df->data_len == msk->write_seq;
994 }
995
dfrag_uncharge(struct sock * sk,int len)996 static void dfrag_uncharge(struct sock *sk, int len)
997 {
998 sk_mem_uncharge(sk, len);
999 sk_wmem_queued_add(sk, -len);
1000 }
1001
dfrag_clear(struct sock * sk,struct mptcp_data_frag * dfrag)1002 static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag)
1003 {
1004 int len = dfrag->data_len + dfrag->overhead;
1005
1006 list_del(&dfrag->list);
1007 dfrag_uncharge(sk, len);
1008 put_page(dfrag->page);
1009 }
1010
1011 /* called under both the msk socket lock and the data lock */
__mptcp_clean_una(struct sock * sk)1012 static void __mptcp_clean_una(struct sock *sk)
1013 {
1014 struct mptcp_sock *msk = mptcp_sk(sk);
1015 struct mptcp_data_frag *dtmp, *dfrag;
1016 u64 snd_una;
1017
1018 snd_una = msk->snd_una;
1019 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) {
1020 if (after64(dfrag->data_seq + dfrag->data_len, snd_una))
1021 break;
1022
1023 if (unlikely(dfrag == msk->first_pending)) {
1024 /* in recovery mode can see ack after the current snd head */
1025 if (WARN_ON_ONCE(!msk->recovery))
1026 break;
1027
1028 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1029 }
1030
1031 dfrag_clear(sk, dfrag);
1032 }
1033
1034 dfrag = mptcp_rtx_head(sk);
1035 if (dfrag && after64(snd_una, dfrag->data_seq)) {
1036 u64 delta = snd_una - dfrag->data_seq;
1037
1038 /* prevent wrap around in recovery mode */
1039 if (unlikely(delta > dfrag->already_sent)) {
1040 if (WARN_ON_ONCE(!msk->recovery))
1041 goto out;
1042 if (WARN_ON_ONCE(delta > dfrag->data_len))
1043 goto out;
1044 dfrag->already_sent += delta - dfrag->already_sent;
1045 }
1046
1047 dfrag->data_seq += delta;
1048 dfrag->offset += delta;
1049 dfrag->data_len -= delta;
1050 dfrag->already_sent -= delta;
1051
1052 dfrag_uncharge(sk, delta);
1053 }
1054
1055 /* all retransmitted data acked, recovery completed */
1056 if (unlikely(msk->recovery) && after64(msk->snd_una, msk->recovery_snd_nxt))
1057 msk->recovery = false;
1058
1059 out:
1060 if (snd_una == msk->snd_nxt && snd_una == msk->write_seq) {
1061 if (mptcp_rtx_timer_pending(sk) && !mptcp_data_fin_enabled(msk))
1062 mptcp_stop_rtx_timer(sk);
1063 } else {
1064 mptcp_reset_rtx_timer(sk);
1065 }
1066
1067 if (mptcp_pending_data_fin_ack(sk))
1068 mptcp_schedule_work(sk);
1069 }
1070
__mptcp_clean_una_wakeup(struct sock * sk)1071 static void __mptcp_clean_una_wakeup(struct sock *sk)
1072 {
1073 lockdep_assert_held_once(&sk->sk_lock.slock);
1074
1075 __mptcp_clean_una(sk);
1076 mptcp_write_space(sk);
1077 }
1078
mptcp_clean_una_wakeup(struct sock * sk)1079 static void mptcp_clean_una_wakeup(struct sock *sk)
1080 {
1081 mptcp_data_lock(sk);
1082 __mptcp_clean_una_wakeup(sk);
1083 mptcp_data_unlock(sk);
1084 }
1085
mptcp_enter_memory_pressure(struct sock * sk)1086 static void mptcp_enter_memory_pressure(struct sock *sk)
1087 {
1088 struct mptcp_subflow_context *subflow;
1089 struct mptcp_sock *msk = mptcp_sk(sk);
1090 bool first = true;
1091
1092 mptcp_for_each_subflow(msk, subflow) {
1093 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
1094
1095 if (first)
1096 tcp_enter_memory_pressure(ssk);
1097 sk_stream_moderate_sndbuf(ssk);
1098
1099 first = false;
1100 }
1101 __mptcp_sync_sndbuf(sk);
1102 }
1103
1104 /* ensure we get enough memory for the frag hdr, beyond some minimal amount of
1105 * data
1106 */
mptcp_page_frag_refill(struct sock * sk,struct page_frag * pfrag)1107 static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag)
1108 {
1109 if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag),
1110 pfrag, sk->sk_allocation)))
1111 return true;
1112
1113 mptcp_enter_memory_pressure(sk);
1114 return false;
1115 }
1116
1117 static struct mptcp_data_frag *
mptcp_carve_data_frag(const struct mptcp_sock * msk,struct page_frag * pfrag,int orig_offset)1118 mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag,
1119 int orig_offset)
1120 {
1121 int offset = ALIGN(orig_offset, sizeof(long));
1122 struct mptcp_data_frag *dfrag;
1123
1124 dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset);
1125 dfrag->data_len = 0;
1126 dfrag->data_seq = msk->write_seq;
1127 dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag);
1128 dfrag->offset = offset + sizeof(struct mptcp_data_frag);
1129 dfrag->already_sent = 0;
1130 dfrag->page = pfrag->page;
1131
1132 return dfrag;
1133 }
1134
1135 struct mptcp_sendmsg_info {
1136 int mss_now;
1137 int size_goal;
1138 u16 limit;
1139 u16 sent;
1140 unsigned int flags;
1141 bool data_lock_held;
1142 };
1143
mptcp_check_allowed_size(const struct mptcp_sock * msk,struct sock * ssk,u64 data_seq,int avail_size)1144 static int mptcp_check_allowed_size(const struct mptcp_sock *msk, struct sock *ssk,
1145 u64 data_seq, int avail_size)
1146 {
1147 u64 window_end = mptcp_wnd_end(msk);
1148 u64 mptcp_snd_wnd;
1149
1150 if (__mptcp_check_fallback(msk))
1151 return avail_size;
1152
1153 mptcp_snd_wnd = window_end - data_seq;
1154 avail_size = min_t(unsigned int, mptcp_snd_wnd, avail_size);
1155
1156 if (unlikely(tcp_sk(ssk)->snd_wnd < mptcp_snd_wnd)) {
1157 tcp_sk(ssk)->snd_wnd = min_t(u64, U32_MAX, mptcp_snd_wnd);
1158 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_SNDWNDSHARED);
1159 }
1160
1161 return avail_size;
1162 }
1163
__mptcp_add_ext(struct sk_buff * skb,gfp_t gfp)1164 static bool __mptcp_add_ext(struct sk_buff *skb, gfp_t gfp)
1165 {
1166 struct skb_ext *mpext = __skb_ext_alloc(gfp);
1167
1168 if (!mpext)
1169 return false;
1170 __skb_ext_set(skb, SKB_EXT_MPTCP, mpext);
1171 return true;
1172 }
1173
__mptcp_do_alloc_tx_skb(struct sock * sk,gfp_t gfp)1174 static struct sk_buff *__mptcp_do_alloc_tx_skb(struct sock *sk, gfp_t gfp)
1175 {
1176 struct sk_buff *skb;
1177
1178 skb = alloc_skb_fclone(MAX_TCP_HEADER, gfp);
1179 if (likely(skb)) {
1180 if (likely(__mptcp_add_ext(skb, gfp))) {
1181 skb_reserve(skb, MAX_TCP_HEADER);
1182 skb->ip_summed = CHECKSUM_PARTIAL;
1183 INIT_LIST_HEAD(&skb->tcp_tsorted_anchor);
1184 return skb;
1185 }
1186 __kfree_skb(skb);
1187 } else {
1188 mptcp_enter_memory_pressure(sk);
1189 }
1190 return NULL;
1191 }
1192
__mptcp_alloc_tx_skb(struct sock * sk,struct sock * ssk,gfp_t gfp)1193 static struct sk_buff *__mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, gfp_t gfp)
1194 {
1195 struct sk_buff *skb;
1196
1197 skb = __mptcp_do_alloc_tx_skb(sk, gfp);
1198 if (!skb)
1199 return NULL;
1200
1201 if (likely(sk_wmem_schedule(ssk, skb->truesize))) {
1202 tcp_skb_entail(ssk, skb);
1203 return skb;
1204 }
1205 tcp_skb_tsorted_anchor_cleanup(skb);
1206 kfree_skb(skb);
1207 return NULL;
1208 }
1209
mptcp_alloc_tx_skb(struct sock * sk,struct sock * ssk,bool data_lock_held)1210 static struct sk_buff *mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, bool data_lock_held)
1211 {
1212 gfp_t gfp = data_lock_held ? GFP_ATOMIC : sk->sk_allocation;
1213
1214 return __mptcp_alloc_tx_skb(sk, ssk, gfp);
1215 }
1216
1217 /* note: this always recompute the csum on the whole skb, even
1218 * if we just appended a single frag. More status info needed
1219 */
mptcp_update_data_checksum(struct sk_buff * skb,int added)1220 static void mptcp_update_data_checksum(struct sk_buff *skb, int added)
1221 {
1222 struct mptcp_ext *mpext = mptcp_get_ext(skb);
1223 __wsum csum = ~csum_unfold(mpext->csum);
1224 int offset = skb->len - added;
1225
1226 mpext->csum = csum_fold(csum_block_add(csum, skb_checksum(skb, offset, added, 0), offset));
1227 }
1228
mptcp_update_infinite_map(struct mptcp_sock * msk,struct sock * ssk,struct mptcp_ext * mpext)1229 static void mptcp_update_infinite_map(struct mptcp_sock *msk,
1230 struct sock *ssk,
1231 struct mptcp_ext *mpext)
1232 {
1233 if (!mpext)
1234 return;
1235
1236 mpext->infinite_map = 1;
1237 mpext->data_len = 0;
1238
1239 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPTX);
1240 mptcp_subflow_ctx(ssk)->send_infinite_map = 0;
1241 pr_fallback(msk);
1242 mptcp_do_fallback(ssk);
1243 }
1244
1245 #define MPTCP_MAX_GSO_SIZE (GSO_LEGACY_MAX_SIZE - (MAX_TCP_HEADER + 1))
1246
mptcp_sendmsg_frag(struct sock * sk,struct sock * ssk,struct mptcp_data_frag * dfrag,struct mptcp_sendmsg_info * info)1247 static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
1248 struct mptcp_data_frag *dfrag,
1249 struct mptcp_sendmsg_info *info)
1250 {
1251 u64 data_seq = dfrag->data_seq + info->sent;
1252 int offset = dfrag->offset + info->sent;
1253 struct mptcp_sock *msk = mptcp_sk(sk);
1254 bool zero_window_probe = false;
1255 struct mptcp_ext *mpext = NULL;
1256 bool can_coalesce = false;
1257 bool reuse_skb = true;
1258 struct sk_buff *skb;
1259 size_t copy;
1260 int i;
1261
1262 pr_debug("msk=%p ssk=%p sending dfrag at seq=%llu len=%u already sent=%u\n",
1263 msk, ssk, dfrag->data_seq, dfrag->data_len, info->sent);
1264
1265 if (WARN_ON_ONCE(info->sent > info->limit ||
1266 info->limit > dfrag->data_len))
1267 return 0;
1268
1269 if (unlikely(!__tcp_can_send(ssk)))
1270 return -EAGAIN;
1271
1272 /* compute send limit */
1273 if (unlikely(ssk->sk_gso_max_size > MPTCP_MAX_GSO_SIZE))
1274 ssk->sk_gso_max_size = MPTCP_MAX_GSO_SIZE;
1275 info->mss_now = tcp_send_mss(ssk, &info->size_goal, info->flags);
1276 copy = info->size_goal;
1277
1278 skb = tcp_write_queue_tail(ssk);
1279 if (skb && copy > skb->len) {
1280 /* Limit the write to the size available in the
1281 * current skb, if any, so that we create at most a new skb.
1282 * Explicitly tells TCP internals to avoid collapsing on later
1283 * queue management operation, to avoid breaking the ext <->
1284 * SSN association set here
1285 */
1286 mpext = mptcp_get_ext(skb);
1287 if (!mptcp_skb_can_collapse_to(data_seq, skb, mpext)) {
1288 TCP_SKB_CB(skb)->eor = 1;
1289 tcp_mark_push(tcp_sk(ssk), skb);
1290 goto alloc_skb;
1291 }
1292
1293 i = skb_shinfo(skb)->nr_frags;
1294 can_coalesce = skb_can_coalesce(skb, i, dfrag->page, offset);
1295 if (!can_coalesce && i >= READ_ONCE(net_hotdata.sysctl_max_skb_frags)) {
1296 tcp_mark_push(tcp_sk(ssk), skb);
1297 goto alloc_skb;
1298 }
1299
1300 copy -= skb->len;
1301 } else {
1302 alloc_skb:
1303 skb = mptcp_alloc_tx_skb(sk, ssk, info->data_lock_held);
1304 if (!skb)
1305 return -ENOMEM;
1306
1307 i = skb_shinfo(skb)->nr_frags;
1308 reuse_skb = false;
1309 mpext = mptcp_get_ext(skb);
1310 }
1311
1312 /* Zero window and all data acked? Probe. */
1313 copy = mptcp_check_allowed_size(msk, ssk, data_seq, copy);
1314 if (copy == 0) {
1315 u64 snd_una = READ_ONCE(msk->snd_una);
1316
1317 if (snd_una != msk->snd_nxt || tcp_write_queue_tail(ssk)) {
1318 tcp_remove_empty_skb(ssk);
1319 return 0;
1320 }
1321
1322 zero_window_probe = true;
1323 data_seq = snd_una - 1;
1324 copy = 1;
1325 }
1326
1327 copy = min_t(size_t, copy, info->limit - info->sent);
1328 if (!sk_wmem_schedule(ssk, copy)) {
1329 tcp_remove_empty_skb(ssk);
1330 return -ENOMEM;
1331 }
1332
1333 if (can_coalesce) {
1334 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1335 } else {
1336 get_page(dfrag->page);
1337 skb_fill_page_desc(skb, i, dfrag->page, offset, copy);
1338 }
1339
1340 skb->len += copy;
1341 skb->data_len += copy;
1342 skb->truesize += copy;
1343 sk_wmem_queued_add(ssk, copy);
1344 sk_mem_charge(ssk, copy);
1345 WRITE_ONCE(tcp_sk(ssk)->write_seq, tcp_sk(ssk)->write_seq + copy);
1346 TCP_SKB_CB(skb)->end_seq += copy;
1347 tcp_skb_pcount_set(skb, 0);
1348
1349 /* on skb reuse we just need to update the DSS len */
1350 if (reuse_skb) {
1351 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1352 mpext->data_len += copy;
1353 goto out;
1354 }
1355
1356 memset(mpext, 0, sizeof(*mpext));
1357 mpext->data_seq = data_seq;
1358 mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq;
1359 mpext->data_len = copy;
1360 mpext->use_map = 1;
1361 mpext->dsn64 = 1;
1362
1363 pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d\n",
1364 mpext->data_seq, mpext->subflow_seq, mpext->data_len,
1365 mpext->dsn64);
1366
1367 if (zero_window_probe) {
1368 mptcp_subflow_ctx(ssk)->rel_write_seq += copy;
1369 mpext->frozen = 1;
1370 if (READ_ONCE(msk->csum_enabled))
1371 mptcp_update_data_checksum(skb, copy);
1372 tcp_push_pending_frames(ssk);
1373 return 0;
1374 }
1375 out:
1376 if (READ_ONCE(msk->csum_enabled))
1377 mptcp_update_data_checksum(skb, copy);
1378 if (mptcp_subflow_ctx(ssk)->send_infinite_map)
1379 mptcp_update_infinite_map(msk, ssk, mpext);
1380 trace_mptcp_sendmsg_frag(mpext);
1381 mptcp_subflow_ctx(ssk)->rel_write_seq += copy;
1382 return copy;
1383 }
1384
1385 #define MPTCP_SEND_BURST_SIZE ((1 << 16) - \
1386 sizeof(struct tcphdr) - \
1387 MAX_TCP_OPTION_SPACE - \
1388 sizeof(struct ipv6hdr) - \
1389 sizeof(struct frag_hdr))
1390
1391 struct subflow_send_info {
1392 struct sock *ssk;
1393 u64 linger_time;
1394 };
1395
mptcp_subflow_set_active(struct mptcp_subflow_context * subflow)1396 void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow)
1397 {
1398 if (!subflow->stale)
1399 return;
1400
1401 subflow->stale = 0;
1402 MPTCP_INC_STATS(sock_net(mptcp_subflow_tcp_sock(subflow)), MPTCP_MIB_SUBFLOWRECOVER);
1403 }
1404
mptcp_subflow_active(struct mptcp_subflow_context * subflow)1405 bool mptcp_subflow_active(struct mptcp_subflow_context *subflow)
1406 {
1407 if (unlikely(subflow->stale)) {
1408 u32 rcv_tstamp = READ_ONCE(tcp_sk(mptcp_subflow_tcp_sock(subflow))->rcv_tstamp);
1409
1410 if (subflow->stale_rcv_tstamp == rcv_tstamp)
1411 return false;
1412
1413 mptcp_subflow_set_active(subflow);
1414 }
1415 return __mptcp_subflow_active(subflow);
1416 }
1417
1418 #define SSK_MODE_ACTIVE 0
1419 #define SSK_MODE_BACKUP 1
1420 #define SSK_MODE_MAX 2
1421
1422 /* implement the mptcp packet scheduler;
1423 * returns the subflow that will transmit the next DSS
1424 * additionally updates the rtx timeout
1425 */
mptcp_subflow_get_send(struct mptcp_sock * msk)1426 struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk)
1427 {
1428 struct subflow_send_info send_info[SSK_MODE_MAX];
1429 struct mptcp_subflow_context *subflow;
1430 struct sock *sk = (struct sock *)msk;
1431 u32 pace, burst, wmem;
1432 int i, nr_active = 0;
1433 struct sock *ssk;
1434 u64 linger_time;
1435 long tout = 0;
1436
1437 /* pick the subflow with the lower wmem/wspace ratio */
1438 for (i = 0; i < SSK_MODE_MAX; ++i) {
1439 send_info[i].ssk = NULL;
1440 send_info[i].linger_time = -1;
1441 }
1442
1443 mptcp_for_each_subflow(msk, subflow) {
1444 bool backup = subflow->backup || subflow->request_bkup;
1445
1446 trace_mptcp_subflow_get_send(subflow);
1447 ssk = mptcp_subflow_tcp_sock(subflow);
1448 if (!mptcp_subflow_active(subflow))
1449 continue;
1450
1451 tout = max(tout, mptcp_timeout_from_subflow(subflow));
1452 nr_active += !backup;
1453 pace = subflow->avg_pacing_rate;
1454 if (unlikely(!pace)) {
1455 /* init pacing rate from socket */
1456 subflow->avg_pacing_rate = READ_ONCE(ssk->sk_pacing_rate);
1457 pace = subflow->avg_pacing_rate;
1458 if (!pace)
1459 continue;
1460 }
1461
1462 linger_time = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32, pace);
1463 if (linger_time < send_info[backup].linger_time) {
1464 send_info[backup].ssk = ssk;
1465 send_info[backup].linger_time = linger_time;
1466 }
1467 }
1468 __mptcp_set_timeout(sk, tout);
1469
1470 /* pick the best backup if no other subflow is active */
1471 if (!nr_active)
1472 send_info[SSK_MODE_ACTIVE].ssk = send_info[SSK_MODE_BACKUP].ssk;
1473
1474 /* According to the blest algorithm, to avoid HoL blocking for the
1475 * faster flow, we need to:
1476 * - estimate the faster flow linger time
1477 * - use the above to estimate the amount of byte transferred
1478 * by the faster flow
1479 * - check that the amount of queued data is greter than the above,
1480 * otherwise do not use the picked, slower, subflow
1481 * We select the subflow with the shorter estimated time to flush
1482 * the queued mem, which basically ensure the above. We just need
1483 * to check that subflow has a non empty cwin.
1484 */
1485 ssk = send_info[SSK_MODE_ACTIVE].ssk;
1486 if (!ssk || !sk_stream_memory_free(ssk))
1487 return NULL;
1488
1489 burst = min_t(int, MPTCP_SEND_BURST_SIZE, mptcp_wnd_end(msk) - msk->snd_nxt);
1490 wmem = READ_ONCE(ssk->sk_wmem_queued);
1491 if (!burst)
1492 return ssk;
1493
1494 subflow = mptcp_subflow_ctx(ssk);
1495 subflow->avg_pacing_rate = div_u64((u64)subflow->avg_pacing_rate * wmem +
1496 READ_ONCE(ssk->sk_pacing_rate) * burst,
1497 burst + wmem);
1498 msk->snd_burst = burst;
1499 return ssk;
1500 }
1501
mptcp_push_release(struct sock * ssk,struct mptcp_sendmsg_info * info)1502 static void mptcp_push_release(struct sock *ssk, struct mptcp_sendmsg_info *info)
1503 {
1504 tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal);
1505 release_sock(ssk);
1506 }
1507
mptcp_update_post_push(struct mptcp_sock * msk,struct mptcp_data_frag * dfrag,u32 sent)1508 static void mptcp_update_post_push(struct mptcp_sock *msk,
1509 struct mptcp_data_frag *dfrag,
1510 u32 sent)
1511 {
1512 u64 snd_nxt_new = dfrag->data_seq;
1513
1514 dfrag->already_sent += sent;
1515
1516 msk->snd_burst -= sent;
1517
1518 snd_nxt_new += dfrag->already_sent;
1519
1520 /* snd_nxt_new can be smaller than snd_nxt in case mptcp
1521 * is recovering after a failover. In that event, this re-sends
1522 * old segments.
1523 *
1524 * Thus compute snd_nxt_new candidate based on
1525 * the dfrag->data_seq that was sent and the data
1526 * that has been handed to the subflow for transmission
1527 * and skip update in case it was old dfrag.
1528 */
1529 if (likely(after64(snd_nxt_new, msk->snd_nxt))) {
1530 msk->bytes_sent += snd_nxt_new - msk->snd_nxt;
1531 WRITE_ONCE(msk->snd_nxt, snd_nxt_new);
1532 }
1533 }
1534
mptcp_check_and_set_pending(struct sock * sk)1535 void mptcp_check_and_set_pending(struct sock *sk)
1536 {
1537 if (mptcp_send_head(sk)) {
1538 mptcp_data_lock(sk);
1539 mptcp_sk(sk)->cb_flags |= BIT(MPTCP_PUSH_PENDING);
1540 mptcp_data_unlock(sk);
1541 }
1542 }
1543
__subflow_push_pending(struct sock * sk,struct sock * ssk,struct mptcp_sendmsg_info * info)1544 static int __subflow_push_pending(struct sock *sk, struct sock *ssk,
1545 struct mptcp_sendmsg_info *info)
1546 {
1547 struct mptcp_sock *msk = mptcp_sk(sk);
1548 struct mptcp_data_frag *dfrag;
1549 int len, copied = 0, err = 0;
1550
1551 while ((dfrag = mptcp_send_head(sk))) {
1552 info->sent = dfrag->already_sent;
1553 info->limit = dfrag->data_len;
1554 len = dfrag->data_len - dfrag->already_sent;
1555 while (len > 0) {
1556 int ret = 0;
1557
1558 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, info);
1559 if (ret <= 0) {
1560 err = copied ? : ret;
1561 goto out;
1562 }
1563
1564 info->sent += ret;
1565 copied += ret;
1566 len -= ret;
1567
1568 mptcp_update_post_push(msk, dfrag, ret);
1569 }
1570 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1571
1572 if (msk->snd_burst <= 0 ||
1573 !sk_stream_memory_free(ssk) ||
1574 !mptcp_subflow_active(mptcp_subflow_ctx(ssk))) {
1575 err = copied;
1576 goto out;
1577 }
1578 mptcp_set_timeout(sk);
1579 }
1580 err = copied;
1581
1582 out:
1583 if (err > 0)
1584 msk->last_data_sent = tcp_jiffies32;
1585 return err;
1586 }
1587
__mptcp_push_pending(struct sock * sk,unsigned int flags)1588 void __mptcp_push_pending(struct sock *sk, unsigned int flags)
1589 {
1590 struct sock *prev_ssk = NULL, *ssk = NULL;
1591 struct mptcp_sock *msk = mptcp_sk(sk);
1592 struct mptcp_sendmsg_info info = {
1593 .flags = flags,
1594 };
1595 bool do_check_data_fin = false;
1596 int push_count = 1;
1597
1598 while (mptcp_send_head(sk) && (push_count > 0)) {
1599 struct mptcp_subflow_context *subflow;
1600 int ret = 0;
1601
1602 if (mptcp_sched_get_send(msk))
1603 break;
1604
1605 push_count = 0;
1606
1607 mptcp_for_each_subflow(msk, subflow) {
1608 if (READ_ONCE(subflow->scheduled)) {
1609 mptcp_subflow_set_scheduled(subflow, false);
1610
1611 prev_ssk = ssk;
1612 ssk = mptcp_subflow_tcp_sock(subflow);
1613 if (ssk != prev_ssk) {
1614 /* First check. If the ssk has changed since
1615 * the last round, release prev_ssk
1616 */
1617 if (prev_ssk)
1618 mptcp_push_release(prev_ssk, &info);
1619
1620 /* Need to lock the new subflow only if different
1621 * from the previous one, otherwise we are still
1622 * helding the relevant lock
1623 */
1624 lock_sock(ssk);
1625 }
1626
1627 push_count++;
1628
1629 ret = __subflow_push_pending(sk, ssk, &info);
1630 if (ret <= 0) {
1631 if (ret != -EAGAIN ||
1632 (1 << ssk->sk_state) &
1633 (TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSE))
1634 push_count--;
1635 continue;
1636 }
1637 do_check_data_fin = true;
1638 }
1639 }
1640 }
1641
1642 /* at this point we held the socket lock for the last subflow we used */
1643 if (ssk)
1644 mptcp_push_release(ssk, &info);
1645
1646 /* ensure the rtx timer is running */
1647 if (!mptcp_rtx_timer_pending(sk))
1648 mptcp_reset_rtx_timer(sk);
1649 if (do_check_data_fin)
1650 mptcp_check_send_data_fin(sk);
1651 }
1652
__mptcp_subflow_push_pending(struct sock * sk,struct sock * ssk,bool first)1653 static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk, bool first)
1654 {
1655 struct mptcp_sock *msk = mptcp_sk(sk);
1656 struct mptcp_sendmsg_info info = {
1657 .data_lock_held = true,
1658 };
1659 bool keep_pushing = true;
1660 struct sock *xmit_ssk;
1661 int copied = 0;
1662
1663 info.flags = 0;
1664 while (mptcp_send_head(sk) && keep_pushing) {
1665 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1666 int ret = 0;
1667
1668 /* check for a different subflow usage only after
1669 * spooling the first chunk of data
1670 */
1671 if (first) {
1672 mptcp_subflow_set_scheduled(subflow, false);
1673 ret = __subflow_push_pending(sk, ssk, &info);
1674 first = false;
1675 if (ret <= 0)
1676 break;
1677 copied += ret;
1678 continue;
1679 }
1680
1681 if (mptcp_sched_get_send(msk))
1682 goto out;
1683
1684 if (READ_ONCE(subflow->scheduled)) {
1685 mptcp_subflow_set_scheduled(subflow, false);
1686 ret = __subflow_push_pending(sk, ssk, &info);
1687 if (ret <= 0)
1688 keep_pushing = false;
1689 copied += ret;
1690 }
1691
1692 mptcp_for_each_subflow(msk, subflow) {
1693 if (READ_ONCE(subflow->scheduled)) {
1694 xmit_ssk = mptcp_subflow_tcp_sock(subflow);
1695 if (xmit_ssk != ssk) {
1696 mptcp_subflow_delegate(subflow,
1697 MPTCP_DELEGATE_SEND);
1698 keep_pushing = false;
1699 }
1700 }
1701 }
1702 }
1703
1704 out:
1705 /* __mptcp_alloc_tx_skb could have released some wmem and we are
1706 * not going to flush it via release_sock()
1707 */
1708 if (copied) {
1709 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
1710 info.size_goal);
1711 if (!mptcp_rtx_timer_pending(sk))
1712 mptcp_reset_rtx_timer(sk);
1713
1714 if (msk->snd_data_fin_enable &&
1715 msk->snd_nxt + 1 == msk->write_seq)
1716 mptcp_schedule_work(sk);
1717 }
1718 }
1719
1720 static int mptcp_disconnect(struct sock *sk, int flags);
1721
mptcp_sendmsg_fastopen(struct sock * sk,struct msghdr * msg,size_t len,int * copied_syn)1722 static int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
1723 size_t len, int *copied_syn)
1724 {
1725 unsigned int saved_flags = msg->msg_flags;
1726 struct mptcp_sock *msk = mptcp_sk(sk);
1727 struct sock *ssk;
1728 int ret;
1729
1730 /* on flags based fastopen the mptcp is supposed to create the
1731 * first subflow right now. Otherwise we are in the defer_connect
1732 * path, and the first subflow must be already present.
1733 * Since the defer_connect flag is cleared after the first succsful
1734 * fastopen attempt, no need to check for additional subflow status.
1735 */
1736 if (msg->msg_flags & MSG_FASTOPEN) {
1737 ssk = __mptcp_nmpc_sk(msk);
1738 if (IS_ERR(ssk))
1739 return PTR_ERR(ssk);
1740 }
1741 if (!msk->first)
1742 return -EINVAL;
1743
1744 ssk = msk->first;
1745
1746 lock_sock(ssk);
1747 msg->msg_flags |= MSG_DONTWAIT;
1748 msk->fastopening = 1;
1749 ret = tcp_sendmsg_fastopen(ssk, msg, copied_syn, len, NULL);
1750 msk->fastopening = 0;
1751 msg->msg_flags = saved_flags;
1752 release_sock(ssk);
1753
1754 /* do the blocking bits of inet_stream_connect outside the ssk socket lock */
1755 if (ret == -EINPROGRESS && !(msg->msg_flags & MSG_DONTWAIT)) {
1756 ret = __inet_stream_connect(sk->sk_socket, msg->msg_name,
1757 msg->msg_namelen, msg->msg_flags, 1);
1758
1759 /* Keep the same behaviour of plain TCP: zero the copied bytes in
1760 * case of any error, except timeout or signal
1761 */
1762 if (ret && ret != -EINPROGRESS && ret != -ERESTARTSYS && ret != -EINTR)
1763 *copied_syn = 0;
1764 } else if (ret && ret != -EINPROGRESS) {
1765 /* The disconnect() op called by tcp_sendmsg_fastopen()/
1766 * __inet_stream_connect() can fail, due to looking check,
1767 * see mptcp_disconnect().
1768 * Attempt it again outside the problematic scope.
1769 */
1770 if (!mptcp_disconnect(sk, 0)) {
1771 sk->sk_disconnects++;
1772 sk->sk_socket->state = SS_UNCONNECTED;
1773 }
1774 }
1775 inet_clear_bit(DEFER_CONNECT, sk);
1776
1777 return ret;
1778 }
1779
do_copy_data_nocache(struct sock * sk,int copy,struct iov_iter * from,char * to)1780 static int do_copy_data_nocache(struct sock *sk, int copy,
1781 struct iov_iter *from, char *to)
1782 {
1783 if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) {
1784 if (!copy_from_iter_full_nocache(to, copy, from))
1785 return -EFAULT;
1786 } else if (!copy_from_iter_full(to, copy, from)) {
1787 return -EFAULT;
1788 }
1789 return 0;
1790 }
1791
1792 /* open-code sk_stream_memory_free() plus sent limit computation to
1793 * avoid indirect calls in fast-path.
1794 * Called under the msk socket lock, so we can avoid a bunch of ONCE
1795 * annotations.
1796 */
mptcp_send_limit(const struct sock * sk)1797 static u32 mptcp_send_limit(const struct sock *sk)
1798 {
1799 const struct mptcp_sock *msk = mptcp_sk(sk);
1800 u32 limit, not_sent;
1801
1802 if (sk->sk_wmem_queued >= READ_ONCE(sk->sk_sndbuf))
1803 return 0;
1804
1805 limit = mptcp_notsent_lowat(sk);
1806 if (limit == UINT_MAX)
1807 return UINT_MAX;
1808
1809 not_sent = msk->write_seq - msk->snd_nxt;
1810 if (not_sent >= limit)
1811 return 0;
1812
1813 return limit - not_sent;
1814 }
1815
mptcp_sendmsg(struct sock * sk,struct msghdr * msg,size_t len)1816 static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
1817 {
1818 struct mptcp_sock *msk = mptcp_sk(sk);
1819 struct page_frag *pfrag;
1820 size_t copied = 0;
1821 int ret = 0;
1822 long timeo;
1823
1824 /* silently ignore everything else */
1825 msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | MSG_FASTOPEN;
1826
1827 lock_sock(sk);
1828
1829 if (unlikely(inet_test_bit(DEFER_CONNECT, sk) ||
1830 msg->msg_flags & MSG_FASTOPEN)) {
1831 int copied_syn = 0;
1832
1833 ret = mptcp_sendmsg_fastopen(sk, msg, len, &copied_syn);
1834 copied += copied_syn;
1835 if (ret == -EINPROGRESS && copied_syn > 0)
1836 goto out;
1837 else if (ret)
1838 goto do_error;
1839 }
1840
1841 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1842
1843 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
1844 ret = sk_stream_wait_connect(sk, &timeo);
1845 if (ret)
1846 goto do_error;
1847 }
1848
1849 ret = -EPIPE;
1850 if (unlikely(sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)))
1851 goto do_error;
1852
1853 pfrag = sk_page_frag(sk);
1854
1855 while (msg_data_left(msg)) {
1856 int total_ts, frag_truesize = 0;
1857 struct mptcp_data_frag *dfrag;
1858 bool dfrag_collapsed;
1859 size_t psize, offset;
1860 u32 copy_limit;
1861
1862 /* ensure fitting the notsent_lowat() constraint */
1863 copy_limit = mptcp_send_limit(sk);
1864 if (!copy_limit)
1865 goto wait_for_memory;
1866
1867 /* reuse tail pfrag, if possible, or carve a new one from the
1868 * page allocator
1869 */
1870 dfrag = mptcp_pending_tail(sk);
1871 dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag);
1872 if (!dfrag_collapsed) {
1873 if (!mptcp_page_frag_refill(sk, pfrag))
1874 goto wait_for_memory;
1875
1876 dfrag = mptcp_carve_data_frag(msk, pfrag, pfrag->offset);
1877 frag_truesize = dfrag->overhead;
1878 }
1879
1880 /* we do not bound vs wspace, to allow a single packet.
1881 * memory accounting will prevent execessive memory usage
1882 * anyway
1883 */
1884 offset = dfrag->offset + dfrag->data_len;
1885 psize = pfrag->size - offset;
1886 psize = min_t(size_t, psize, msg_data_left(msg));
1887 psize = min_t(size_t, psize, copy_limit);
1888 total_ts = psize + frag_truesize;
1889
1890 if (!sk_wmem_schedule(sk, total_ts))
1891 goto wait_for_memory;
1892
1893 ret = do_copy_data_nocache(sk, psize, &msg->msg_iter,
1894 page_address(dfrag->page) + offset);
1895 if (ret)
1896 goto do_error;
1897
1898 /* data successfully copied into the write queue */
1899 sk_forward_alloc_add(sk, -total_ts);
1900 copied += psize;
1901 dfrag->data_len += psize;
1902 frag_truesize += psize;
1903 pfrag->offset += frag_truesize;
1904 WRITE_ONCE(msk->write_seq, msk->write_seq + psize);
1905
1906 /* charge data on mptcp pending queue to the msk socket
1907 * Note: we charge such data both to sk and ssk
1908 */
1909 sk_wmem_queued_add(sk, frag_truesize);
1910 if (!dfrag_collapsed) {
1911 get_page(dfrag->page);
1912 list_add_tail(&dfrag->list, &msk->rtx_queue);
1913 if (!msk->first_pending)
1914 WRITE_ONCE(msk->first_pending, dfrag);
1915 }
1916 pr_debug("msk=%p dfrag at seq=%llu len=%u sent=%u new=%d\n", msk,
1917 dfrag->data_seq, dfrag->data_len, dfrag->already_sent,
1918 !dfrag_collapsed);
1919
1920 continue;
1921
1922 wait_for_memory:
1923 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1924 __mptcp_push_pending(sk, msg->msg_flags);
1925 ret = sk_stream_wait_memory(sk, &timeo);
1926 if (ret)
1927 goto do_error;
1928 }
1929
1930 if (copied)
1931 __mptcp_push_pending(sk, msg->msg_flags);
1932
1933 out:
1934 release_sock(sk);
1935 return copied;
1936
1937 do_error:
1938 if (copied)
1939 goto out;
1940
1941 copied = sk_stream_error(sk, msg->msg_flags, ret);
1942 goto out;
1943 }
1944
1945 static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied);
1946
__mptcp_recvmsg_mskq(struct mptcp_sock * msk,struct msghdr * msg,size_t len,int flags,struct scm_timestamping_internal * tss,int * cmsg_flags)1947 static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk,
1948 struct msghdr *msg,
1949 size_t len, int flags,
1950 struct scm_timestamping_internal *tss,
1951 int *cmsg_flags)
1952 {
1953 struct sk_buff *skb, *tmp;
1954 int copied = 0;
1955
1956 skb_queue_walk_safe(&msk->receive_queue, skb, tmp) {
1957 u32 offset = MPTCP_SKB_CB(skb)->offset;
1958 u32 data_len = skb->len - offset;
1959 u32 count = min_t(size_t, len - copied, data_len);
1960 int err;
1961
1962 if (!(flags & MSG_TRUNC)) {
1963 err = skb_copy_datagram_msg(skb, offset, msg, count);
1964 if (unlikely(err < 0)) {
1965 if (!copied)
1966 return err;
1967 break;
1968 }
1969 }
1970
1971 if (MPTCP_SKB_CB(skb)->has_rxtstamp) {
1972 tcp_update_recv_tstamps(skb, tss);
1973 *cmsg_flags |= MPTCP_CMSG_TS;
1974 }
1975
1976 copied += count;
1977
1978 if (count < data_len) {
1979 if (!(flags & MSG_PEEK)) {
1980 MPTCP_SKB_CB(skb)->offset += count;
1981 MPTCP_SKB_CB(skb)->map_seq += count;
1982 msk->bytes_consumed += count;
1983 }
1984 break;
1985 }
1986
1987 if (!(flags & MSG_PEEK)) {
1988 /* we will bulk release the skb memory later */
1989 skb->destructor = NULL;
1990 WRITE_ONCE(msk->rmem_released, msk->rmem_released + skb->truesize);
1991 __skb_unlink(skb, &msk->receive_queue);
1992 __kfree_skb(skb);
1993 msk->bytes_consumed += count;
1994 }
1995
1996 if (copied >= len)
1997 break;
1998 }
1999
2000 mptcp_rcv_space_adjust(msk, copied);
2001 return copied;
2002 }
2003
2004 /* receive buffer autotuning. See tcp_rcv_space_adjust for more information.
2005 *
2006 * Only difference: Use highest rtt estimate of the subflows in use.
2007 */
mptcp_rcv_space_adjust(struct mptcp_sock * msk,int copied)2008 static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied)
2009 {
2010 struct mptcp_subflow_context *subflow;
2011 struct sock *sk = (struct sock *)msk;
2012 u8 scaling_ratio = U8_MAX;
2013 u32 time, advmss = 1;
2014 u64 rtt_us, mstamp;
2015
2016 msk_owned_by_me(msk);
2017
2018 if (copied <= 0)
2019 return;
2020
2021 if (!msk->rcvspace_init)
2022 mptcp_rcv_space_init(msk, msk->first);
2023
2024 msk->rcvq_space.copied += copied;
2025
2026 mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC);
2027 time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time);
2028
2029 rtt_us = msk->rcvq_space.rtt_us;
2030 if (rtt_us && time < (rtt_us >> 3))
2031 return;
2032
2033 rtt_us = 0;
2034 mptcp_for_each_subflow(msk, subflow) {
2035 const struct tcp_sock *tp;
2036 u64 sf_rtt_us;
2037 u32 sf_advmss;
2038
2039 tp = tcp_sk(mptcp_subflow_tcp_sock(subflow));
2040
2041 sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us);
2042 sf_advmss = READ_ONCE(tp->advmss);
2043
2044 rtt_us = max(sf_rtt_us, rtt_us);
2045 advmss = max(sf_advmss, advmss);
2046 scaling_ratio = min(tp->scaling_ratio, scaling_ratio);
2047 }
2048
2049 msk->rcvq_space.rtt_us = rtt_us;
2050 msk->scaling_ratio = scaling_ratio;
2051 if (time < (rtt_us >> 3) || rtt_us == 0)
2052 return;
2053
2054 if (msk->rcvq_space.copied <= msk->rcvq_space.space)
2055 goto new_measure;
2056
2057 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf) &&
2058 !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
2059 u64 rcvwin, grow;
2060 int rcvbuf;
2061
2062 rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss;
2063
2064 grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space);
2065
2066 do_div(grow, msk->rcvq_space.space);
2067 rcvwin += (grow << 1);
2068
2069 rcvbuf = min_t(u64, mptcp_space_from_win(sk, rcvwin),
2070 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[2]));
2071
2072 if (rcvbuf > sk->sk_rcvbuf) {
2073 u32 window_clamp;
2074
2075 window_clamp = mptcp_win_from_space(sk, rcvbuf);
2076 WRITE_ONCE(sk->sk_rcvbuf, rcvbuf);
2077
2078 /* Make subflows follow along. If we do not do this, we
2079 * get drops at subflow level if skbs can't be moved to
2080 * the mptcp rx queue fast enough (announced rcv_win can
2081 * exceed ssk->sk_rcvbuf).
2082 */
2083 mptcp_for_each_subflow(msk, subflow) {
2084 struct sock *ssk;
2085 bool slow;
2086
2087 ssk = mptcp_subflow_tcp_sock(subflow);
2088 slow = lock_sock_fast(ssk);
2089 WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf);
2090 WRITE_ONCE(tcp_sk(ssk)->window_clamp, window_clamp);
2091 if (tcp_can_send_ack(ssk))
2092 tcp_cleanup_rbuf(ssk, 1);
2093 unlock_sock_fast(ssk, slow);
2094 }
2095 }
2096 }
2097
2098 msk->rcvq_space.space = msk->rcvq_space.copied;
2099 new_measure:
2100 msk->rcvq_space.copied = 0;
2101 msk->rcvq_space.time = mstamp;
2102 }
2103
__mptcp_update_rmem(struct sock * sk)2104 static void __mptcp_update_rmem(struct sock *sk)
2105 {
2106 struct mptcp_sock *msk = mptcp_sk(sk);
2107
2108 if (!msk->rmem_released)
2109 return;
2110
2111 atomic_sub(msk->rmem_released, &sk->sk_rmem_alloc);
2112 mptcp_rmem_uncharge(sk, msk->rmem_released);
2113 WRITE_ONCE(msk->rmem_released, 0);
2114 }
2115
__mptcp_splice_receive_queue(struct sock * sk)2116 static void __mptcp_splice_receive_queue(struct sock *sk)
2117 {
2118 struct mptcp_sock *msk = mptcp_sk(sk);
2119
2120 skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue);
2121 }
2122
__mptcp_move_skbs(struct mptcp_sock * msk)2123 static bool __mptcp_move_skbs(struct mptcp_sock *msk)
2124 {
2125 struct sock *sk = (struct sock *)msk;
2126 unsigned int moved = 0;
2127 bool ret, done;
2128
2129 do {
2130 struct sock *ssk = mptcp_subflow_recv_lookup(msk);
2131 bool slowpath;
2132
2133 /* we can have data pending in the subflows only if the msk
2134 * receive buffer was full at subflow_data_ready() time,
2135 * that is an unlikely slow path.
2136 */
2137 if (likely(!ssk))
2138 break;
2139
2140 slowpath = lock_sock_fast(ssk);
2141 mptcp_data_lock(sk);
2142 __mptcp_update_rmem(sk);
2143 done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
2144 mptcp_data_unlock(sk);
2145
2146 if (unlikely(ssk->sk_err))
2147 __mptcp_error_report(sk);
2148 unlock_sock_fast(ssk, slowpath);
2149 } while (!done);
2150
2151 /* acquire the data lock only if some input data is pending */
2152 ret = moved > 0;
2153 if (!RB_EMPTY_ROOT(&msk->out_of_order_queue) ||
2154 !skb_queue_empty_lockless(&sk->sk_receive_queue)) {
2155 mptcp_data_lock(sk);
2156 __mptcp_update_rmem(sk);
2157 ret |= __mptcp_ofo_queue(msk);
2158 __mptcp_splice_receive_queue(sk);
2159 mptcp_data_unlock(sk);
2160 }
2161 if (ret)
2162 mptcp_check_data_fin((struct sock *)msk);
2163 return !skb_queue_empty(&msk->receive_queue);
2164 }
2165
mptcp_inq_hint(const struct sock * sk)2166 static unsigned int mptcp_inq_hint(const struct sock *sk)
2167 {
2168 const struct mptcp_sock *msk = mptcp_sk(sk);
2169 const struct sk_buff *skb;
2170
2171 skb = skb_peek(&msk->receive_queue);
2172 if (skb) {
2173 u64 hint_val = READ_ONCE(msk->ack_seq) - MPTCP_SKB_CB(skb)->map_seq;
2174
2175 if (hint_val >= INT_MAX)
2176 return INT_MAX;
2177
2178 return (unsigned int)hint_val;
2179 }
2180
2181 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
2182 return 1;
2183
2184 return 0;
2185 }
2186
mptcp_recvmsg(struct sock * sk,struct msghdr * msg,size_t len,int flags,int * addr_len)2187 static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
2188 int flags, int *addr_len)
2189 {
2190 struct mptcp_sock *msk = mptcp_sk(sk);
2191 struct scm_timestamping_internal tss;
2192 int copied = 0, cmsg_flags = 0;
2193 int target;
2194 long timeo;
2195
2196 /* MSG_ERRQUEUE is really a no-op till we support IP_RECVERR */
2197 if (unlikely(flags & MSG_ERRQUEUE))
2198 return inet_recv_error(sk, msg, len, addr_len);
2199
2200 lock_sock(sk);
2201 if (unlikely(sk->sk_state == TCP_LISTEN)) {
2202 copied = -ENOTCONN;
2203 goto out_err;
2204 }
2205
2206 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2207
2208 len = min_t(size_t, len, INT_MAX);
2209 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
2210
2211 if (unlikely(msk->recvmsg_inq))
2212 cmsg_flags = MPTCP_CMSG_INQ;
2213
2214 while (copied < len) {
2215 int err, bytes_read;
2216
2217 bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags, &tss, &cmsg_flags);
2218 if (unlikely(bytes_read < 0)) {
2219 if (!copied)
2220 copied = bytes_read;
2221 goto out_err;
2222 }
2223
2224 copied += bytes_read;
2225
2226 if (skb_queue_empty(&msk->receive_queue) && __mptcp_move_skbs(msk))
2227 continue;
2228
2229 /* only the MPTCP socket status is relevant here. The exit
2230 * conditions mirror closely tcp_recvmsg()
2231 */
2232 if (copied >= target)
2233 break;
2234
2235 if (copied) {
2236 if (sk->sk_err ||
2237 sk->sk_state == TCP_CLOSE ||
2238 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2239 !timeo ||
2240 signal_pending(current))
2241 break;
2242 } else {
2243 if (sk->sk_err) {
2244 copied = sock_error(sk);
2245 break;
2246 }
2247
2248 if (sk->sk_shutdown & RCV_SHUTDOWN) {
2249 /* race breaker: the shutdown could be after the
2250 * previous receive queue check
2251 */
2252 if (__mptcp_move_skbs(msk))
2253 continue;
2254 break;
2255 }
2256
2257 if (sk->sk_state == TCP_CLOSE) {
2258 copied = -ENOTCONN;
2259 break;
2260 }
2261
2262 if (!timeo) {
2263 copied = -EAGAIN;
2264 break;
2265 }
2266
2267 if (signal_pending(current)) {
2268 copied = sock_intr_errno(timeo);
2269 break;
2270 }
2271 }
2272
2273 pr_debug("block timeout %ld\n", timeo);
2274 mptcp_cleanup_rbuf(msk, copied);
2275 err = sk_wait_data(sk, &timeo, NULL);
2276 if (err < 0) {
2277 err = copied ? : err;
2278 goto out_err;
2279 }
2280 }
2281
2282 mptcp_cleanup_rbuf(msk, copied);
2283
2284 out_err:
2285 if (cmsg_flags && copied >= 0) {
2286 if (cmsg_flags & MPTCP_CMSG_TS)
2287 tcp_recv_timestamp(msg, sk, &tss);
2288
2289 if (cmsg_flags & MPTCP_CMSG_INQ) {
2290 unsigned int inq = mptcp_inq_hint(sk);
2291
2292 put_cmsg(msg, SOL_TCP, TCP_CM_INQ, sizeof(inq), &inq);
2293 }
2294 }
2295
2296 pr_debug("msk=%p rx queue empty=%d:%d copied=%d\n",
2297 msk, skb_queue_empty_lockless(&sk->sk_receive_queue),
2298 skb_queue_empty(&msk->receive_queue), copied);
2299
2300 release_sock(sk);
2301 return copied;
2302 }
2303
mptcp_retransmit_timer(struct timer_list * t)2304 static void mptcp_retransmit_timer(struct timer_list *t)
2305 {
2306 struct inet_connection_sock *icsk = from_timer(icsk, t,
2307 icsk_retransmit_timer);
2308 struct sock *sk = &icsk->icsk_inet.sk;
2309 struct mptcp_sock *msk = mptcp_sk(sk);
2310
2311 bh_lock_sock(sk);
2312 if (!sock_owned_by_user(sk)) {
2313 /* we need a process context to retransmit */
2314 if (!test_and_set_bit(MPTCP_WORK_RTX, &msk->flags))
2315 mptcp_schedule_work(sk);
2316 } else {
2317 /* delegate our work to tcp_release_cb() */
2318 __set_bit(MPTCP_RETRANSMIT, &msk->cb_flags);
2319 }
2320 bh_unlock_sock(sk);
2321 sock_put(sk);
2322 }
2323
mptcp_tout_timer(struct timer_list * t)2324 static void mptcp_tout_timer(struct timer_list *t)
2325 {
2326 struct sock *sk = from_timer(sk, t, sk_timer);
2327
2328 mptcp_schedule_work(sk);
2329 sock_put(sk);
2330 }
2331
2332 /* Find an idle subflow. Return NULL if there is unacked data at tcp
2333 * level.
2334 *
2335 * A backup subflow is returned only if that is the only kind available.
2336 */
mptcp_subflow_get_retrans(struct mptcp_sock * msk)2337 struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk)
2338 {
2339 struct sock *backup = NULL, *pick = NULL;
2340 struct mptcp_subflow_context *subflow;
2341 int min_stale_count = INT_MAX;
2342
2343 mptcp_for_each_subflow(msk, subflow) {
2344 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2345
2346 if (!__mptcp_subflow_active(subflow))
2347 continue;
2348
2349 /* still data outstanding at TCP level? skip this */
2350 if (!tcp_rtx_and_write_queues_empty(ssk)) {
2351 mptcp_pm_subflow_chk_stale(msk, ssk);
2352 min_stale_count = min_t(int, min_stale_count, subflow->stale_count);
2353 continue;
2354 }
2355
2356 if (subflow->backup || subflow->request_bkup) {
2357 if (!backup)
2358 backup = ssk;
2359 continue;
2360 }
2361
2362 if (!pick)
2363 pick = ssk;
2364 }
2365
2366 if (pick)
2367 return pick;
2368
2369 /* use backup only if there are no progresses anywhere */
2370 return min_stale_count > 1 ? backup : NULL;
2371 }
2372
__mptcp_retransmit_pending_data(struct sock * sk)2373 bool __mptcp_retransmit_pending_data(struct sock *sk)
2374 {
2375 struct mptcp_data_frag *cur, *rtx_head;
2376 struct mptcp_sock *msk = mptcp_sk(sk);
2377
2378 if (__mptcp_check_fallback(msk))
2379 return false;
2380
2381 /* the closing socket has some data untransmitted and/or unacked:
2382 * some data in the mptcp rtx queue has not really xmitted yet.
2383 * keep it simple and re-inject the whole mptcp level rtx queue
2384 */
2385 mptcp_data_lock(sk);
2386 __mptcp_clean_una_wakeup(sk);
2387 rtx_head = mptcp_rtx_head(sk);
2388 if (!rtx_head) {
2389 mptcp_data_unlock(sk);
2390 return false;
2391 }
2392
2393 msk->recovery_snd_nxt = msk->snd_nxt;
2394 msk->recovery = true;
2395 mptcp_data_unlock(sk);
2396
2397 msk->first_pending = rtx_head;
2398 msk->snd_burst = 0;
2399
2400 /* be sure to clear the "sent status" on all re-injected fragments */
2401 list_for_each_entry(cur, &msk->rtx_queue, list) {
2402 if (!cur->already_sent)
2403 break;
2404 cur->already_sent = 0;
2405 }
2406
2407 return true;
2408 }
2409
2410 /* flags for __mptcp_close_ssk() */
2411 #define MPTCP_CF_PUSH BIT(1)
2412 #define MPTCP_CF_FASTCLOSE BIT(2)
2413
2414 /* be sure to send a reset only if the caller asked for it, also
2415 * clean completely the subflow status when the subflow reaches
2416 * TCP_CLOSE state
2417 */
__mptcp_subflow_disconnect(struct sock * ssk,struct mptcp_subflow_context * subflow,unsigned int flags)2418 static void __mptcp_subflow_disconnect(struct sock *ssk,
2419 struct mptcp_subflow_context *subflow,
2420 unsigned int flags)
2421 {
2422 if (((1 << ssk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) ||
2423 (flags & MPTCP_CF_FASTCLOSE)) {
2424 /* The MPTCP code never wait on the subflow sockets, TCP-level
2425 * disconnect should never fail
2426 */
2427 WARN_ON_ONCE(tcp_disconnect(ssk, 0));
2428 mptcp_subflow_ctx_reset(subflow);
2429 } else {
2430 tcp_shutdown(ssk, SEND_SHUTDOWN);
2431 }
2432 }
2433
2434 /* subflow sockets can be either outgoing (connect) or incoming
2435 * (accept).
2436 *
2437 * Outgoing subflows use in-kernel sockets.
2438 * Incoming subflows do not have their own 'struct socket' allocated,
2439 * so we need to use tcp_close() after detaching them from the mptcp
2440 * parent socket.
2441 */
__mptcp_close_ssk(struct sock * sk,struct sock * ssk,struct mptcp_subflow_context * subflow,unsigned int flags)2442 static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
2443 struct mptcp_subflow_context *subflow,
2444 unsigned int flags)
2445 {
2446 struct mptcp_sock *msk = mptcp_sk(sk);
2447 bool dispose_it, need_push = false;
2448
2449 /* If the first subflow moved to a close state before accept, e.g. due
2450 * to an incoming reset or listener shutdown, the subflow socket is
2451 * already deleted by inet_child_forget() and the mptcp socket can't
2452 * survive too.
2453 */
2454 if (msk->in_accept_queue && msk->first == ssk &&
2455 (sock_flag(sk, SOCK_DEAD) || sock_flag(ssk, SOCK_DEAD))) {
2456 /* ensure later check in mptcp_worker() will dispose the msk */
2457 sock_set_flag(sk, SOCK_DEAD);
2458 mptcp_set_close_tout(sk, tcp_jiffies32 - (mptcp_close_timeout(sk) + 1));
2459 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
2460 mptcp_subflow_drop_ctx(ssk);
2461 goto out_release;
2462 }
2463
2464 dispose_it = msk->free_first || ssk != msk->first;
2465 if (dispose_it)
2466 list_del(&subflow->node);
2467
2468 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
2469
2470 if ((flags & MPTCP_CF_FASTCLOSE) && !__mptcp_check_fallback(msk)) {
2471 /* be sure to force the tcp_close path
2472 * to generate the egress reset
2473 */
2474 ssk->sk_lingertime = 0;
2475 sock_set_flag(ssk, SOCK_LINGER);
2476 subflow->send_fastclose = 1;
2477 }
2478
2479 need_push = (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(sk);
2480 if (!dispose_it) {
2481 __mptcp_subflow_disconnect(ssk, subflow, flags);
2482 release_sock(ssk);
2483
2484 goto out;
2485 }
2486
2487 subflow->disposable = 1;
2488
2489 /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops
2490 * the ssk has been already destroyed, we just need to release the
2491 * reference owned by msk;
2492 */
2493 if (!inet_csk(ssk)->icsk_ulp_ops) {
2494 WARN_ON_ONCE(!sock_flag(ssk, SOCK_DEAD));
2495 kfree_rcu(subflow, rcu);
2496 } else {
2497 /* otherwise tcp will dispose of the ssk and subflow ctx */
2498 __tcp_close(ssk, 0);
2499
2500 /* close acquired an extra ref */
2501 __sock_put(ssk);
2502 }
2503
2504 out_release:
2505 __mptcp_subflow_error_report(sk, ssk);
2506 release_sock(ssk);
2507
2508 sock_put(ssk);
2509
2510 if (ssk == msk->first)
2511 WRITE_ONCE(msk->first, NULL);
2512
2513 out:
2514 __mptcp_sync_sndbuf(sk);
2515 if (need_push)
2516 __mptcp_push_pending(sk, 0);
2517
2518 /* Catch every 'all subflows closed' scenario, including peers silently
2519 * closing them, e.g. due to timeout.
2520 * For established sockets, allow an additional timeout before closing,
2521 * as the protocol can still create more subflows.
2522 */
2523 if (list_is_singular(&msk->conn_list) && msk->first &&
2524 inet_sk_state_load(msk->first) == TCP_CLOSE) {
2525 if (sk->sk_state != TCP_ESTABLISHED ||
2526 msk->in_accept_queue || sock_flag(sk, SOCK_DEAD)) {
2527 mptcp_set_state(sk, TCP_CLOSE);
2528 mptcp_close_wake_up(sk);
2529 } else {
2530 mptcp_start_tout_timer(sk);
2531 }
2532 }
2533 }
2534
mptcp_close_ssk(struct sock * sk,struct sock * ssk,struct mptcp_subflow_context * subflow)2535 void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
2536 struct mptcp_subflow_context *subflow)
2537 {
2538 /* The first subflow can already be closed and still in the list */
2539 if (subflow->close_event_done)
2540 return;
2541
2542 subflow->close_event_done = true;
2543
2544 if (sk->sk_state == TCP_ESTABLISHED)
2545 mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL);
2546
2547 /* subflow aborted before reaching the fully_established status
2548 * attempt the creation of the next subflow
2549 */
2550 mptcp_pm_subflow_check_next(mptcp_sk(sk), subflow);
2551
2552 __mptcp_close_ssk(sk, ssk, subflow, MPTCP_CF_PUSH);
2553 }
2554
mptcp_sync_mss(struct sock * sk,u32 pmtu)2555 static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu)
2556 {
2557 return 0;
2558 }
2559
__mptcp_close_subflow(struct sock * sk)2560 static void __mptcp_close_subflow(struct sock *sk)
2561 {
2562 struct mptcp_subflow_context *subflow, *tmp;
2563 struct mptcp_sock *msk = mptcp_sk(sk);
2564
2565 might_sleep();
2566
2567 mptcp_for_each_subflow_safe(msk, subflow, tmp) {
2568 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2569 int ssk_state = inet_sk_state_load(ssk);
2570
2571 if (ssk_state != TCP_CLOSE &&
2572 (ssk_state != TCP_CLOSE_WAIT ||
2573 inet_sk_state_load(sk) != TCP_ESTABLISHED))
2574 continue;
2575
2576 /* 'subflow_data_ready' will re-sched once rx queue is empty */
2577 if (!skb_queue_empty_lockless(&ssk->sk_receive_queue))
2578 continue;
2579
2580 mptcp_close_ssk(sk, ssk, subflow);
2581 }
2582
2583 }
2584
mptcp_close_tout_expired(const struct sock * sk)2585 static bool mptcp_close_tout_expired(const struct sock *sk)
2586 {
2587 if (!inet_csk(sk)->icsk_mtup.probe_timestamp ||
2588 sk->sk_state == TCP_CLOSE)
2589 return false;
2590
2591 return time_after32(tcp_jiffies32,
2592 inet_csk(sk)->icsk_mtup.probe_timestamp + mptcp_close_timeout(sk));
2593 }
2594
mptcp_check_fastclose(struct mptcp_sock * msk)2595 static void mptcp_check_fastclose(struct mptcp_sock *msk)
2596 {
2597 struct mptcp_subflow_context *subflow, *tmp;
2598 struct sock *sk = (struct sock *)msk;
2599
2600 if (likely(!READ_ONCE(msk->rcv_fastclose)))
2601 return;
2602
2603 mptcp_token_destroy(msk);
2604
2605 mptcp_for_each_subflow_safe(msk, subflow, tmp) {
2606 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
2607 bool slow;
2608
2609 slow = lock_sock_fast(tcp_sk);
2610 if (tcp_sk->sk_state != TCP_CLOSE) {
2611 mptcp_send_active_reset_reason(tcp_sk);
2612 tcp_set_state(tcp_sk, TCP_CLOSE);
2613 }
2614 unlock_sock_fast(tcp_sk, slow);
2615 }
2616
2617 /* Mirror the tcp_reset() error propagation */
2618 switch (sk->sk_state) {
2619 case TCP_SYN_SENT:
2620 WRITE_ONCE(sk->sk_err, ECONNREFUSED);
2621 break;
2622 case TCP_CLOSE_WAIT:
2623 WRITE_ONCE(sk->sk_err, EPIPE);
2624 break;
2625 case TCP_CLOSE:
2626 return;
2627 default:
2628 WRITE_ONCE(sk->sk_err, ECONNRESET);
2629 }
2630
2631 mptcp_set_state(sk, TCP_CLOSE);
2632 WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
2633 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
2634 set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags);
2635
2636 /* the calling mptcp_worker will properly destroy the socket */
2637 if (sock_flag(sk, SOCK_DEAD))
2638 return;
2639
2640 sk->sk_state_change(sk);
2641 sk_error_report(sk);
2642 }
2643
__mptcp_retrans(struct sock * sk)2644 static void __mptcp_retrans(struct sock *sk)
2645 {
2646 struct mptcp_sock *msk = mptcp_sk(sk);
2647 struct mptcp_subflow_context *subflow;
2648 struct mptcp_sendmsg_info info = {};
2649 struct mptcp_data_frag *dfrag;
2650 struct sock *ssk;
2651 int ret, err;
2652 u16 len = 0;
2653
2654 mptcp_clean_una_wakeup(sk);
2655
2656 /* first check ssk: need to kick "stale" logic */
2657 err = mptcp_sched_get_retrans(msk);
2658 dfrag = mptcp_rtx_head(sk);
2659 if (!dfrag) {
2660 if (mptcp_data_fin_enabled(msk)) {
2661 struct inet_connection_sock *icsk = inet_csk(sk);
2662
2663 icsk->icsk_retransmits++;
2664 mptcp_set_datafin_timeout(sk);
2665 mptcp_send_ack(msk);
2666
2667 goto reset_timer;
2668 }
2669
2670 if (!mptcp_send_head(sk))
2671 return;
2672
2673 goto reset_timer;
2674 }
2675
2676 if (err)
2677 goto reset_timer;
2678
2679 mptcp_for_each_subflow(msk, subflow) {
2680 if (READ_ONCE(subflow->scheduled)) {
2681 u16 copied = 0;
2682
2683 mptcp_subflow_set_scheduled(subflow, false);
2684
2685 ssk = mptcp_subflow_tcp_sock(subflow);
2686
2687 lock_sock(ssk);
2688
2689 /* limit retransmission to the bytes already sent on some subflows */
2690 info.sent = 0;
2691 info.limit = READ_ONCE(msk->csum_enabled) ? dfrag->data_len :
2692 dfrag->already_sent;
2693 while (info.sent < info.limit) {
2694 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
2695 if (ret <= 0)
2696 break;
2697
2698 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS);
2699 copied += ret;
2700 info.sent += ret;
2701 }
2702 if (copied) {
2703 len = max(copied, len);
2704 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
2705 info.size_goal);
2706 WRITE_ONCE(msk->allow_infinite_fallback, false);
2707 }
2708
2709 release_sock(ssk);
2710 }
2711 }
2712
2713 msk->bytes_retrans += len;
2714 dfrag->already_sent = max(dfrag->already_sent, len);
2715
2716 reset_timer:
2717 mptcp_check_and_set_pending(sk);
2718
2719 if (!mptcp_rtx_timer_pending(sk))
2720 mptcp_reset_rtx_timer(sk);
2721 }
2722
2723 /* schedule the timeout timer for the relevant event: either close timeout
2724 * or mp_fail timeout. The close timeout takes precedence on the mp_fail one
2725 */
mptcp_reset_tout_timer(struct mptcp_sock * msk,unsigned long fail_tout)2726 void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout)
2727 {
2728 struct sock *sk = (struct sock *)msk;
2729 unsigned long timeout, close_timeout;
2730
2731 if (!fail_tout && !inet_csk(sk)->icsk_mtup.probe_timestamp)
2732 return;
2733
2734 close_timeout = (unsigned long)inet_csk(sk)->icsk_mtup.probe_timestamp -
2735 tcp_jiffies32 + jiffies + mptcp_close_timeout(sk);
2736
2737 /* the close timeout takes precedence on the fail one, and here at least one of
2738 * them is active
2739 */
2740 timeout = inet_csk(sk)->icsk_mtup.probe_timestamp ? close_timeout : fail_tout;
2741
2742 sk_reset_timer(sk, &sk->sk_timer, timeout);
2743 }
2744
mptcp_mp_fail_no_response(struct mptcp_sock * msk)2745 static void mptcp_mp_fail_no_response(struct mptcp_sock *msk)
2746 {
2747 struct sock *ssk = msk->first;
2748 bool slow;
2749
2750 if (!ssk)
2751 return;
2752
2753 pr_debug("MP_FAIL doesn't respond, reset the subflow\n");
2754
2755 slow = lock_sock_fast(ssk);
2756 mptcp_subflow_reset(ssk);
2757 WRITE_ONCE(mptcp_subflow_ctx(ssk)->fail_tout, 0);
2758 unlock_sock_fast(ssk, slow);
2759 }
2760
mptcp_do_fastclose(struct sock * sk)2761 static void mptcp_do_fastclose(struct sock *sk)
2762 {
2763 struct mptcp_subflow_context *subflow, *tmp;
2764 struct mptcp_sock *msk = mptcp_sk(sk);
2765
2766 mptcp_set_state(sk, TCP_CLOSE);
2767 mptcp_for_each_subflow_safe(msk, subflow, tmp)
2768 __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow),
2769 subflow, MPTCP_CF_FASTCLOSE);
2770 }
2771
mptcp_worker(struct work_struct * work)2772 static void mptcp_worker(struct work_struct *work)
2773 {
2774 struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
2775 struct sock *sk = (struct sock *)msk;
2776 unsigned long fail_tout;
2777 int state;
2778
2779 lock_sock(sk);
2780 state = sk->sk_state;
2781 if (unlikely((1 << state) & (TCPF_CLOSE | TCPF_LISTEN)))
2782 goto unlock;
2783
2784 mptcp_check_fastclose(msk);
2785
2786 mptcp_pm_nl_work(msk);
2787
2788 mptcp_check_send_data_fin(sk);
2789 mptcp_check_data_fin_ack(sk);
2790 mptcp_check_data_fin(sk);
2791
2792 if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
2793 __mptcp_close_subflow(sk);
2794
2795 if (mptcp_close_tout_expired(sk)) {
2796 mptcp_do_fastclose(sk);
2797 mptcp_close_wake_up(sk);
2798 }
2799
2800 if (sock_flag(sk, SOCK_DEAD) && sk->sk_state == TCP_CLOSE) {
2801 __mptcp_destroy_sock(sk);
2802 goto unlock;
2803 }
2804
2805 if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
2806 __mptcp_retrans(sk);
2807
2808 fail_tout = msk->first ? READ_ONCE(mptcp_subflow_ctx(msk->first)->fail_tout) : 0;
2809 if (fail_tout && time_after(jiffies, fail_tout))
2810 mptcp_mp_fail_no_response(msk);
2811
2812 unlock:
2813 release_sock(sk);
2814 sock_put(sk);
2815 }
2816
__mptcp_init_sock(struct sock * sk)2817 static void __mptcp_init_sock(struct sock *sk)
2818 {
2819 struct mptcp_sock *msk = mptcp_sk(sk);
2820
2821 INIT_LIST_HEAD(&msk->conn_list);
2822 INIT_LIST_HEAD(&msk->join_list);
2823 INIT_LIST_HEAD(&msk->rtx_queue);
2824 INIT_WORK(&msk->work, mptcp_worker);
2825 __skb_queue_head_init(&msk->receive_queue);
2826 msk->out_of_order_queue = RB_ROOT;
2827 msk->first_pending = NULL;
2828 WRITE_ONCE(msk->rmem_fwd_alloc, 0);
2829 WRITE_ONCE(msk->rmem_released, 0);
2830 msk->timer_ival = TCP_RTO_MIN;
2831 msk->scaling_ratio = TCP_DEFAULT_SCALING_RATIO;
2832
2833 WRITE_ONCE(msk->first, NULL);
2834 inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss;
2835 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
2836 WRITE_ONCE(msk->allow_infinite_fallback, true);
2837 msk->recovery = false;
2838 msk->subflow_id = 1;
2839 msk->last_data_sent = tcp_jiffies32;
2840 msk->last_data_recv = tcp_jiffies32;
2841 msk->last_ack_recv = tcp_jiffies32;
2842
2843 mptcp_pm_data_init(msk);
2844
2845 /* re-use the csk retrans timer for MPTCP-level retrans */
2846 timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0);
2847 timer_setup(&sk->sk_timer, mptcp_tout_timer, 0);
2848 }
2849
mptcp_ca_reset(struct sock * sk)2850 static void mptcp_ca_reset(struct sock *sk)
2851 {
2852 struct inet_connection_sock *icsk = inet_csk(sk);
2853
2854 tcp_assign_congestion_control(sk);
2855 strscpy(mptcp_sk(sk)->ca_name, icsk->icsk_ca_ops->name,
2856 sizeof(mptcp_sk(sk)->ca_name));
2857
2858 /* no need to keep a reference to the ops, the name will suffice */
2859 tcp_cleanup_congestion_control(sk);
2860 icsk->icsk_ca_ops = NULL;
2861 }
2862
mptcp_init_sock(struct sock * sk)2863 static int mptcp_init_sock(struct sock *sk)
2864 {
2865 struct net *net = sock_net(sk);
2866 int ret;
2867
2868 __mptcp_init_sock(sk);
2869
2870 if (!mptcp_is_enabled(net))
2871 return -ENOPROTOOPT;
2872
2873 if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net))
2874 return -ENOMEM;
2875
2876 rcu_read_lock();
2877 ret = mptcp_init_sched(mptcp_sk(sk),
2878 mptcp_sched_find(mptcp_get_scheduler(net)));
2879 rcu_read_unlock();
2880 if (ret)
2881 return ret;
2882
2883 set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags);
2884
2885 /* fetch the ca name; do it outside __mptcp_init_sock(), so that clone will
2886 * propagate the correct value
2887 */
2888 mptcp_ca_reset(sk);
2889
2890 sk_sockets_allocated_inc(sk);
2891 sk->sk_rcvbuf = READ_ONCE(net->ipv4.sysctl_tcp_rmem[1]);
2892 sk->sk_sndbuf = READ_ONCE(net->ipv4.sysctl_tcp_wmem[1]);
2893
2894 return 0;
2895 }
2896
__mptcp_clear_xmit(struct sock * sk)2897 static void __mptcp_clear_xmit(struct sock *sk)
2898 {
2899 struct mptcp_sock *msk = mptcp_sk(sk);
2900 struct mptcp_data_frag *dtmp, *dfrag;
2901
2902 WRITE_ONCE(msk->first_pending, NULL);
2903 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list)
2904 dfrag_clear(sk, dfrag);
2905 }
2906
mptcp_cancel_work(struct sock * sk)2907 void mptcp_cancel_work(struct sock *sk)
2908 {
2909 struct mptcp_sock *msk = mptcp_sk(sk);
2910
2911 if (cancel_work_sync(&msk->work))
2912 __sock_put(sk);
2913 }
2914
mptcp_subflow_shutdown(struct sock * sk,struct sock * ssk,int how)2915 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how)
2916 {
2917 lock_sock(ssk);
2918
2919 switch (ssk->sk_state) {
2920 case TCP_LISTEN:
2921 if (!(how & RCV_SHUTDOWN))
2922 break;
2923 fallthrough;
2924 case TCP_SYN_SENT:
2925 WARN_ON_ONCE(tcp_disconnect(ssk, O_NONBLOCK));
2926 break;
2927 default:
2928 if (__mptcp_check_fallback(mptcp_sk(sk))) {
2929 pr_debug("Fallback\n");
2930 ssk->sk_shutdown |= how;
2931 tcp_shutdown(ssk, how);
2932
2933 /* simulate the data_fin ack reception to let the state
2934 * machine move forward
2935 */
2936 WRITE_ONCE(mptcp_sk(sk)->snd_una, mptcp_sk(sk)->snd_nxt);
2937 mptcp_schedule_work(sk);
2938 } else {
2939 pr_debug("Sending DATA_FIN on subflow %p\n", ssk);
2940 tcp_send_ack(ssk);
2941 if (!mptcp_rtx_timer_pending(sk))
2942 mptcp_reset_rtx_timer(sk);
2943 }
2944 break;
2945 }
2946
2947 release_sock(ssk);
2948 }
2949
mptcp_set_state(struct sock * sk,int state)2950 void mptcp_set_state(struct sock *sk, int state)
2951 {
2952 int oldstate = sk->sk_state;
2953
2954 switch (state) {
2955 case TCP_ESTABLISHED:
2956 if (oldstate != TCP_ESTABLISHED)
2957 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_CURRESTAB);
2958 break;
2959 case TCP_CLOSE_WAIT:
2960 /* Unlike TCP, MPTCP sk would not have the TCP_SYN_RECV state:
2961 * MPTCP "accepted" sockets will be created later on. So no
2962 * transition from TCP_SYN_RECV to TCP_CLOSE_WAIT.
2963 */
2964 break;
2965 default:
2966 if (oldstate == TCP_ESTABLISHED || oldstate == TCP_CLOSE_WAIT)
2967 MPTCP_DEC_STATS(sock_net(sk), MPTCP_MIB_CURRESTAB);
2968 }
2969
2970 inet_sk_state_store(sk, state);
2971 }
2972
2973 static const unsigned char new_state[16] = {
2974 /* current state: new state: action: */
2975 [0 /* (Invalid) */] = TCP_CLOSE,
2976 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2977 [TCP_SYN_SENT] = TCP_CLOSE,
2978 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2979 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1,
2980 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2,
2981 [TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */
2982 [TCP_CLOSE] = TCP_CLOSE,
2983 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN,
2984 [TCP_LAST_ACK] = TCP_LAST_ACK,
2985 [TCP_LISTEN] = TCP_CLOSE,
2986 [TCP_CLOSING] = TCP_CLOSING,
2987 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */
2988 };
2989
mptcp_close_state(struct sock * sk)2990 static int mptcp_close_state(struct sock *sk)
2991 {
2992 int next = (int)new_state[sk->sk_state];
2993 int ns = next & TCP_STATE_MASK;
2994
2995 mptcp_set_state(sk, ns);
2996
2997 return next & TCP_ACTION_FIN;
2998 }
2999
mptcp_check_send_data_fin(struct sock * sk)3000 static void mptcp_check_send_data_fin(struct sock *sk)
3001 {
3002 struct mptcp_subflow_context *subflow;
3003 struct mptcp_sock *msk = mptcp_sk(sk);
3004
3005 pr_debug("msk=%p snd_data_fin_enable=%d pending=%d snd_nxt=%llu write_seq=%llu\n",
3006 msk, msk->snd_data_fin_enable, !!mptcp_send_head(sk),
3007 msk->snd_nxt, msk->write_seq);
3008
3009 /* we still need to enqueue subflows or not really shutting down,
3010 * skip this
3011 */
3012 if (!msk->snd_data_fin_enable || msk->snd_nxt + 1 != msk->write_seq ||
3013 mptcp_send_head(sk))
3014 return;
3015
3016 WRITE_ONCE(msk->snd_nxt, msk->write_seq);
3017
3018 mptcp_for_each_subflow(msk, subflow) {
3019 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
3020
3021 mptcp_subflow_shutdown(sk, tcp_sk, SEND_SHUTDOWN);
3022 }
3023 }
3024
__mptcp_wr_shutdown(struct sock * sk)3025 static void __mptcp_wr_shutdown(struct sock *sk)
3026 {
3027 struct mptcp_sock *msk = mptcp_sk(sk);
3028
3029 pr_debug("msk=%p snd_data_fin_enable=%d shutdown=%x state=%d pending=%d\n",
3030 msk, msk->snd_data_fin_enable, sk->sk_shutdown, sk->sk_state,
3031 !!mptcp_send_head(sk));
3032
3033 /* will be ignored by fallback sockets */
3034 WRITE_ONCE(msk->write_seq, msk->write_seq + 1);
3035 WRITE_ONCE(msk->snd_data_fin_enable, 1);
3036
3037 mptcp_check_send_data_fin(sk);
3038 }
3039
__mptcp_destroy_sock(struct sock * sk)3040 static void __mptcp_destroy_sock(struct sock *sk)
3041 {
3042 struct mptcp_sock *msk = mptcp_sk(sk);
3043
3044 pr_debug("msk=%p\n", msk);
3045
3046 might_sleep();
3047
3048 mptcp_stop_rtx_timer(sk);
3049 sk_stop_timer(sk, &sk->sk_timer);
3050 msk->pm.status = 0;
3051 mptcp_release_sched(msk);
3052
3053 sk->sk_prot->destroy(sk);
3054
3055 WARN_ON_ONCE(READ_ONCE(msk->rmem_fwd_alloc));
3056 WARN_ON_ONCE(msk->rmem_released);
3057 sk_stream_kill_queues(sk);
3058 xfrm_sk_free_policy(sk);
3059
3060 sock_put(sk);
3061 }
3062
__mptcp_unaccepted_force_close(struct sock * sk)3063 void __mptcp_unaccepted_force_close(struct sock *sk)
3064 {
3065 sock_set_flag(sk, SOCK_DEAD);
3066 mptcp_do_fastclose(sk);
3067 __mptcp_destroy_sock(sk);
3068 }
3069
mptcp_check_readable(struct sock * sk)3070 static __poll_t mptcp_check_readable(struct sock *sk)
3071 {
3072 return mptcp_epollin_ready(sk) ? EPOLLIN | EPOLLRDNORM : 0;
3073 }
3074
mptcp_check_listen_stop(struct sock * sk)3075 static void mptcp_check_listen_stop(struct sock *sk)
3076 {
3077 struct sock *ssk;
3078
3079 if (inet_sk_state_load(sk) != TCP_LISTEN)
3080 return;
3081
3082 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
3083 ssk = mptcp_sk(sk)->first;
3084 if (WARN_ON_ONCE(!ssk || inet_sk_state_load(ssk) != TCP_LISTEN))
3085 return;
3086
3087 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
3088 tcp_set_state(ssk, TCP_CLOSE);
3089 mptcp_subflow_queue_clean(sk, ssk);
3090 inet_csk_listen_stop(ssk);
3091 mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CLOSED);
3092 release_sock(ssk);
3093 }
3094
__mptcp_close(struct sock * sk,long timeout)3095 bool __mptcp_close(struct sock *sk, long timeout)
3096 {
3097 struct mptcp_subflow_context *subflow;
3098 struct mptcp_sock *msk = mptcp_sk(sk);
3099 bool do_cancel_work = false;
3100 int subflows_alive = 0;
3101
3102 WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
3103
3104 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) {
3105 mptcp_check_listen_stop(sk);
3106 mptcp_set_state(sk, TCP_CLOSE);
3107 goto cleanup;
3108 }
3109
3110 if (mptcp_data_avail(msk) || timeout < 0) {
3111 /* If the msk has read data, or the caller explicitly ask it,
3112 * do the MPTCP equivalent of TCP reset, aka MPTCP fastclose
3113 */
3114 mptcp_do_fastclose(sk);
3115 timeout = 0;
3116 } else if (mptcp_close_state(sk)) {
3117 __mptcp_wr_shutdown(sk);
3118 }
3119
3120 sk_stream_wait_close(sk, timeout);
3121
3122 cleanup:
3123 /* orphan all the subflows */
3124 mptcp_for_each_subflow(msk, subflow) {
3125 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3126 bool slow = lock_sock_fast_nested(ssk);
3127
3128 subflows_alive += ssk->sk_state != TCP_CLOSE;
3129
3130 /* since the close timeout takes precedence on the fail one,
3131 * cancel the latter
3132 */
3133 if (ssk == msk->first)
3134 subflow->fail_tout = 0;
3135
3136 /* detach from the parent socket, but allow data_ready to
3137 * push incoming data into the mptcp stack, to properly ack it
3138 */
3139 ssk->sk_socket = NULL;
3140 ssk->sk_wq = NULL;
3141 unlock_sock_fast(ssk, slow);
3142 }
3143 sock_orphan(sk);
3144
3145 /* all the subflows are closed, only timeout can change the msk
3146 * state, let's not keep resources busy for no reasons
3147 */
3148 if (subflows_alive == 0)
3149 mptcp_set_state(sk, TCP_CLOSE);
3150
3151 sock_hold(sk);
3152 pr_debug("msk=%p state=%d\n", sk, sk->sk_state);
3153 mptcp_pm_connection_closed(msk);
3154
3155 if (sk->sk_state == TCP_CLOSE) {
3156 __mptcp_destroy_sock(sk);
3157 do_cancel_work = true;
3158 } else {
3159 mptcp_start_tout_timer(sk);
3160 }
3161
3162 return do_cancel_work;
3163 }
3164
mptcp_close(struct sock * sk,long timeout)3165 static void mptcp_close(struct sock *sk, long timeout)
3166 {
3167 bool do_cancel_work;
3168
3169 lock_sock(sk);
3170
3171 do_cancel_work = __mptcp_close(sk, timeout);
3172 release_sock(sk);
3173 if (do_cancel_work)
3174 mptcp_cancel_work(sk);
3175
3176 sock_put(sk);
3177 }
3178
mptcp_copy_inaddrs(struct sock * msk,const struct sock * ssk)3179 static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk)
3180 {
3181 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
3182 const struct ipv6_pinfo *ssk6 = inet6_sk(ssk);
3183 struct ipv6_pinfo *msk6 = inet6_sk(msk);
3184
3185 msk->sk_v6_daddr = ssk->sk_v6_daddr;
3186 msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr;
3187
3188 if (msk6 && ssk6) {
3189 msk6->saddr = ssk6->saddr;
3190 msk6->flow_label = ssk6->flow_label;
3191 }
3192 #endif
3193
3194 inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num;
3195 inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport;
3196 inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport;
3197 inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr;
3198 inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr;
3199 inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr;
3200 }
3201
mptcp_disconnect(struct sock * sk,int flags)3202 static int mptcp_disconnect(struct sock *sk, int flags)
3203 {
3204 struct mptcp_sock *msk = mptcp_sk(sk);
3205
3206 /* We are on the fastopen error path. We can't call straight into the
3207 * subflows cleanup code due to lock nesting (we are already under
3208 * msk->firstsocket lock).
3209 */
3210 if (msk->fastopening)
3211 return -EBUSY;
3212
3213 mptcp_check_listen_stop(sk);
3214 mptcp_set_state(sk, TCP_CLOSE);
3215
3216 mptcp_stop_rtx_timer(sk);
3217 mptcp_stop_tout_timer(sk);
3218
3219 mptcp_pm_connection_closed(msk);
3220
3221 /* msk->subflow is still intact, the following will not free the first
3222 * subflow
3223 */
3224 mptcp_destroy_common(msk, MPTCP_CF_FASTCLOSE);
3225 WRITE_ONCE(msk->flags, 0);
3226 msk->cb_flags = 0;
3227 msk->recovery = false;
3228 WRITE_ONCE(msk->can_ack, false);
3229 WRITE_ONCE(msk->fully_established, false);
3230 WRITE_ONCE(msk->rcv_data_fin, false);
3231 WRITE_ONCE(msk->snd_data_fin_enable, false);
3232 WRITE_ONCE(msk->rcv_fastclose, false);
3233 WRITE_ONCE(msk->use_64bit_ack, false);
3234 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
3235 mptcp_pm_data_reset(msk);
3236 mptcp_ca_reset(sk);
3237 msk->bytes_consumed = 0;
3238 msk->bytes_acked = 0;
3239 msk->bytes_received = 0;
3240 msk->bytes_sent = 0;
3241 msk->bytes_retrans = 0;
3242 msk->rcvspace_init = 0;
3243
3244 WRITE_ONCE(sk->sk_shutdown, 0);
3245 sk_error_report(sk);
3246 return 0;
3247 }
3248
3249 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
mptcp_inet6_sk(const struct sock * sk)3250 static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk)
3251 {
3252 unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo);
3253
3254 return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
3255 }
3256
mptcp_copy_ip6_options(struct sock * newsk,const struct sock * sk)3257 static void mptcp_copy_ip6_options(struct sock *newsk, const struct sock *sk)
3258 {
3259 const struct ipv6_pinfo *np = inet6_sk(sk);
3260 struct ipv6_txoptions *opt;
3261 struct ipv6_pinfo *newnp;
3262
3263 newnp = inet6_sk(newsk);
3264
3265 rcu_read_lock();
3266 opt = rcu_dereference(np->opt);
3267 if (opt) {
3268 opt = ipv6_dup_options(newsk, opt);
3269 if (!opt)
3270 net_warn_ratelimited("%s: Failed to copy ip6 options\n", __func__);
3271 }
3272 RCU_INIT_POINTER(newnp->opt, opt);
3273 rcu_read_unlock();
3274 }
3275 #endif
3276
mptcp_copy_ip_options(struct sock * newsk,const struct sock * sk)3277 static void mptcp_copy_ip_options(struct sock *newsk, const struct sock *sk)
3278 {
3279 struct ip_options_rcu *inet_opt, *newopt = NULL;
3280 const struct inet_sock *inet = inet_sk(sk);
3281 struct inet_sock *newinet;
3282
3283 newinet = inet_sk(newsk);
3284
3285 rcu_read_lock();
3286 inet_opt = rcu_dereference(inet->inet_opt);
3287 if (inet_opt) {
3288 newopt = sock_kmalloc(newsk, sizeof(*inet_opt) +
3289 inet_opt->opt.optlen, GFP_ATOMIC);
3290 if (newopt)
3291 memcpy(newopt, inet_opt, sizeof(*inet_opt) +
3292 inet_opt->opt.optlen);
3293 else
3294 net_warn_ratelimited("%s: Failed to copy ip options\n", __func__);
3295 }
3296 RCU_INIT_POINTER(newinet->inet_opt, newopt);
3297 rcu_read_unlock();
3298 }
3299
mptcp_sk_clone_init(const struct sock * sk,const struct mptcp_options_received * mp_opt,struct sock * ssk,struct request_sock * req)3300 struct sock *mptcp_sk_clone_init(const struct sock *sk,
3301 const struct mptcp_options_received *mp_opt,
3302 struct sock *ssk,
3303 struct request_sock *req)
3304 {
3305 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
3306 struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC);
3307 struct mptcp_subflow_context *subflow;
3308 struct mptcp_sock *msk;
3309
3310 if (!nsk)
3311 return NULL;
3312
3313 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
3314 if (nsk->sk_family == AF_INET6)
3315 inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk);
3316 #endif
3317
3318 __mptcp_init_sock(nsk);
3319
3320 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
3321 if (nsk->sk_family == AF_INET6)
3322 mptcp_copy_ip6_options(nsk, sk);
3323 else
3324 #endif
3325 mptcp_copy_ip_options(nsk, sk);
3326
3327 msk = mptcp_sk(nsk);
3328 WRITE_ONCE(msk->local_key, subflow_req->local_key);
3329 WRITE_ONCE(msk->token, subflow_req->token);
3330 msk->in_accept_queue = 1;
3331 WRITE_ONCE(msk->fully_established, false);
3332 if (mp_opt->suboptions & OPTION_MPTCP_CSUMREQD)
3333 WRITE_ONCE(msk->csum_enabled, true);
3334
3335 WRITE_ONCE(msk->write_seq, subflow_req->idsn + 1);
3336 WRITE_ONCE(msk->snd_nxt, msk->write_seq);
3337 WRITE_ONCE(msk->snd_una, msk->write_seq);
3338 WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd);
3339 msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq;
3340 mptcp_init_sched(msk, mptcp_sk(sk)->sched);
3341
3342 /* passive msk is created after the first/MPC subflow */
3343 msk->subflow_id = 2;
3344
3345 sock_reset_flag(nsk, SOCK_RCU_FREE);
3346 security_inet_csk_clone(nsk, req);
3347
3348 /* this can't race with mptcp_close(), as the msk is
3349 * not yet exposted to user-space
3350 */
3351 mptcp_set_state(nsk, TCP_ESTABLISHED);
3352
3353 /* The msk maintain a ref to each subflow in the connections list */
3354 WRITE_ONCE(msk->first, ssk);
3355 subflow = mptcp_subflow_ctx(ssk);
3356 list_add(&subflow->node, &msk->conn_list);
3357 sock_hold(ssk);
3358
3359 /* new mpc subflow takes ownership of the newly
3360 * created mptcp socket
3361 */
3362 mptcp_token_accept(subflow_req, msk);
3363
3364 /* set msk addresses early to ensure mptcp_pm_get_local_id()
3365 * uses the correct data
3366 */
3367 mptcp_copy_inaddrs(nsk, ssk);
3368 __mptcp_propagate_sndbuf(nsk, ssk);
3369
3370 mptcp_rcv_space_init(msk, ssk);
3371
3372 if (mp_opt->suboptions & OPTION_MPTCP_MPC_ACK)
3373 __mptcp_subflow_fully_established(msk, subflow, mp_opt);
3374 bh_unlock_sock(nsk);
3375
3376 /* note: the newly allocated socket refcount is 2 now */
3377 return nsk;
3378 }
3379
mptcp_rcv_space_init(struct mptcp_sock * msk,const struct sock * ssk)3380 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk)
3381 {
3382 const struct tcp_sock *tp = tcp_sk(ssk);
3383
3384 msk->rcvspace_init = 1;
3385 msk->rcvq_space.copied = 0;
3386 msk->rcvq_space.rtt_us = 0;
3387
3388 msk->rcvq_space.time = tp->tcp_mstamp;
3389
3390 /* initial rcv_space offering made to peer */
3391 msk->rcvq_space.space = min_t(u32, tp->rcv_wnd,
3392 TCP_INIT_CWND * tp->advmss);
3393 if (msk->rcvq_space.space == 0)
3394 msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT;
3395 }
3396
mptcp_destroy_common(struct mptcp_sock * msk,unsigned int flags)3397 void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags)
3398 {
3399 struct mptcp_subflow_context *subflow, *tmp;
3400 struct sock *sk = (struct sock *)msk;
3401
3402 __mptcp_clear_xmit(sk);
3403
3404 /* join list will be eventually flushed (with rst) at sock lock release time */
3405 mptcp_for_each_subflow_safe(msk, subflow, tmp)
3406 __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), subflow, flags);
3407
3408 /* move to sk_receive_queue, sk_stream_kill_queues will purge it */
3409 mptcp_data_lock(sk);
3410 skb_queue_splice_tail_init(&msk->receive_queue, &sk->sk_receive_queue);
3411 __skb_queue_purge(&sk->sk_receive_queue);
3412 skb_rbtree_purge(&msk->out_of_order_queue);
3413 mptcp_data_unlock(sk);
3414
3415 /* move all the rx fwd alloc into the sk_mem_reclaim_final in
3416 * inet_sock_destruct() will dispose it
3417 */
3418 sk_forward_alloc_add(sk, msk->rmem_fwd_alloc);
3419 WRITE_ONCE(msk->rmem_fwd_alloc, 0);
3420 mptcp_token_destroy(msk);
3421 mptcp_pm_free_anno_list(msk);
3422 mptcp_free_local_addr_list(msk);
3423 }
3424
mptcp_destroy(struct sock * sk)3425 static void mptcp_destroy(struct sock *sk)
3426 {
3427 struct mptcp_sock *msk = mptcp_sk(sk);
3428
3429 /* allow the following to close even the initial subflow */
3430 msk->free_first = 1;
3431 mptcp_destroy_common(msk, 0);
3432 sk_sockets_allocated_dec(sk);
3433 }
3434
__mptcp_data_acked(struct sock * sk)3435 void __mptcp_data_acked(struct sock *sk)
3436 {
3437 if (!sock_owned_by_user(sk))
3438 __mptcp_clean_una(sk);
3439 else
3440 __set_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->cb_flags);
3441 }
3442
__mptcp_check_push(struct sock * sk,struct sock * ssk)3443 void __mptcp_check_push(struct sock *sk, struct sock *ssk)
3444 {
3445 if (!mptcp_send_head(sk))
3446 return;
3447
3448 if (!sock_owned_by_user(sk))
3449 __mptcp_subflow_push_pending(sk, ssk, false);
3450 else
3451 __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags);
3452 }
3453
3454 #define MPTCP_FLAGS_PROCESS_CTX_NEED (BIT(MPTCP_PUSH_PENDING) | \
3455 BIT(MPTCP_RETRANSMIT) | \
3456 BIT(MPTCP_FLUSH_JOIN_LIST))
3457
3458 /* processes deferred events and flush wmem */
mptcp_release_cb(struct sock * sk)3459 static void mptcp_release_cb(struct sock *sk)
3460 __must_hold(&sk->sk_lock.slock)
3461 {
3462 struct mptcp_sock *msk = mptcp_sk(sk);
3463
3464 for (;;) {
3465 unsigned long flags = (msk->cb_flags & MPTCP_FLAGS_PROCESS_CTX_NEED);
3466 struct list_head join_list;
3467
3468 if (!flags)
3469 break;
3470
3471 INIT_LIST_HEAD(&join_list);
3472 list_splice_init(&msk->join_list, &join_list);
3473
3474 /* the following actions acquire the subflow socket lock
3475 *
3476 * 1) can't be invoked in atomic scope
3477 * 2) must avoid ABBA deadlock with msk socket spinlock: the RX
3478 * datapath acquires the msk socket spinlock while helding
3479 * the subflow socket lock
3480 */
3481 msk->cb_flags &= ~flags;
3482 spin_unlock_bh(&sk->sk_lock.slock);
3483
3484 if (flags & BIT(MPTCP_FLUSH_JOIN_LIST))
3485 __mptcp_flush_join_list(sk, &join_list);
3486 if (flags & BIT(MPTCP_PUSH_PENDING))
3487 __mptcp_push_pending(sk, 0);
3488 if (flags & BIT(MPTCP_RETRANSMIT))
3489 __mptcp_retrans(sk);
3490
3491 cond_resched();
3492 spin_lock_bh(&sk->sk_lock.slock);
3493 }
3494
3495 if (__test_and_clear_bit(MPTCP_CLEAN_UNA, &msk->cb_flags))
3496 __mptcp_clean_una_wakeup(sk);
3497 if (unlikely(msk->cb_flags)) {
3498 /* be sure to sync the msk state before taking actions
3499 * depending on sk_state (MPTCP_ERROR_REPORT)
3500 * On sk release avoid actions depending on the first subflow
3501 */
3502 if (__test_and_clear_bit(MPTCP_SYNC_STATE, &msk->cb_flags) && msk->first)
3503 __mptcp_sync_state(sk, msk->pending_state);
3504 if (__test_and_clear_bit(MPTCP_ERROR_REPORT, &msk->cb_flags))
3505 __mptcp_error_report(sk);
3506 if (__test_and_clear_bit(MPTCP_SYNC_SNDBUF, &msk->cb_flags))
3507 __mptcp_sync_sndbuf(sk);
3508 }
3509
3510 __mptcp_update_rmem(sk);
3511 }
3512
3513 /* MP_JOIN client subflow must wait for 4th ack before sending any data:
3514 * TCP can't schedule delack timer before the subflow is fully established.
3515 * MPTCP uses the delack timer to do 3rd ack retransmissions
3516 */
schedule_3rdack_retransmission(struct sock * ssk)3517 static void schedule_3rdack_retransmission(struct sock *ssk)
3518 {
3519 struct inet_connection_sock *icsk = inet_csk(ssk);
3520 struct tcp_sock *tp = tcp_sk(ssk);
3521 unsigned long timeout;
3522
3523 if (READ_ONCE(mptcp_subflow_ctx(ssk)->fully_established))
3524 return;
3525
3526 /* reschedule with a timeout above RTT, as we must look only for drop */
3527 if (tp->srtt_us)
3528 timeout = usecs_to_jiffies(tp->srtt_us >> (3 - 1));
3529 else
3530 timeout = TCP_TIMEOUT_INIT;
3531 timeout += jiffies;
3532
3533 WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER);
3534 smp_store_release(&icsk->icsk_ack.pending,
3535 icsk->icsk_ack.pending | ICSK_ACK_SCHED | ICSK_ACK_TIMER);
3536 icsk->icsk_ack.timeout = timeout;
3537 sk_reset_timer(ssk, &icsk->icsk_delack_timer, timeout);
3538 }
3539
mptcp_subflow_process_delegated(struct sock * ssk,long status)3540 void mptcp_subflow_process_delegated(struct sock *ssk, long status)
3541 {
3542 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
3543 struct sock *sk = subflow->conn;
3544
3545 if (status & BIT(MPTCP_DELEGATE_SEND)) {
3546 mptcp_data_lock(sk);
3547 if (!sock_owned_by_user(sk))
3548 __mptcp_subflow_push_pending(sk, ssk, true);
3549 else
3550 __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags);
3551 mptcp_data_unlock(sk);
3552 }
3553 if (status & BIT(MPTCP_DELEGATE_SNDBUF)) {
3554 mptcp_data_lock(sk);
3555 if (!sock_owned_by_user(sk))
3556 __mptcp_sync_sndbuf(sk);
3557 else
3558 __set_bit(MPTCP_SYNC_SNDBUF, &mptcp_sk(sk)->cb_flags);
3559 mptcp_data_unlock(sk);
3560 }
3561 if (status & BIT(MPTCP_DELEGATE_ACK))
3562 schedule_3rdack_retransmission(ssk);
3563 }
3564
mptcp_hash(struct sock * sk)3565 static int mptcp_hash(struct sock *sk)
3566 {
3567 /* should never be called,
3568 * we hash the TCP subflows not the MPTCP socket
3569 */
3570 WARN_ON_ONCE(1);
3571 return 0;
3572 }
3573
mptcp_unhash(struct sock * sk)3574 static void mptcp_unhash(struct sock *sk)
3575 {
3576 /* called from sk_common_release(), but nothing to do here */
3577 }
3578
mptcp_get_port(struct sock * sk,unsigned short snum)3579 static int mptcp_get_port(struct sock *sk, unsigned short snum)
3580 {
3581 struct mptcp_sock *msk = mptcp_sk(sk);
3582
3583 pr_debug("msk=%p, ssk=%p\n", msk, msk->first);
3584 if (WARN_ON_ONCE(!msk->first))
3585 return -EINVAL;
3586
3587 return inet_csk_get_port(msk->first, snum);
3588 }
3589
mptcp_finish_connect(struct sock * ssk)3590 void mptcp_finish_connect(struct sock *ssk)
3591 {
3592 struct mptcp_subflow_context *subflow;
3593 struct mptcp_sock *msk;
3594 struct sock *sk;
3595
3596 subflow = mptcp_subflow_ctx(ssk);
3597 sk = subflow->conn;
3598 msk = mptcp_sk(sk);
3599
3600 pr_debug("msk=%p, token=%u\n", sk, subflow->token);
3601
3602 subflow->map_seq = subflow->iasn;
3603 subflow->map_subflow_seq = 1;
3604
3605 /* the socket is not connected yet, no msk/subflow ops can access/race
3606 * accessing the field below
3607 */
3608 WRITE_ONCE(msk->local_key, subflow->local_key);
3609
3610 mptcp_pm_new_connection(msk, ssk, 0);
3611 }
3612
mptcp_sock_graft(struct sock * sk,struct socket * parent)3613 void mptcp_sock_graft(struct sock *sk, struct socket *parent)
3614 {
3615 write_lock_bh(&sk->sk_callback_lock);
3616 rcu_assign_pointer(sk->sk_wq, &parent->wq);
3617 sk_set_socket(sk, parent);
3618 sk->sk_uid = SOCK_INODE(parent)->i_uid;
3619 write_unlock_bh(&sk->sk_callback_lock);
3620 }
3621
mptcp_finish_join(struct sock * ssk)3622 bool mptcp_finish_join(struct sock *ssk)
3623 {
3624 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
3625 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
3626 struct sock *parent = (void *)msk;
3627 bool ret = true;
3628
3629 pr_debug("msk=%p, subflow=%p\n", msk, subflow);
3630
3631 /* mptcp socket already closing? */
3632 if (!mptcp_is_fully_established(parent)) {
3633 subflow->reset_reason = MPTCP_RST_EMPTCP;
3634 return false;
3635 }
3636
3637 /* active subflow, already present inside the conn_list */
3638 if (!list_empty(&subflow->node)) {
3639 mptcp_subflow_joined(msk, ssk);
3640 mptcp_propagate_sndbuf(parent, ssk);
3641 return true;
3642 }
3643
3644 if (!mptcp_pm_allow_new_subflow(msk))
3645 goto err_prohibited;
3646
3647 /* If we can't acquire msk socket lock here, let the release callback
3648 * handle it
3649 */
3650 mptcp_data_lock(parent);
3651 if (!sock_owned_by_user(parent)) {
3652 ret = __mptcp_finish_join(msk, ssk);
3653 if (ret) {
3654 sock_hold(ssk);
3655 list_add_tail(&subflow->node, &msk->conn_list);
3656 }
3657 } else {
3658 sock_hold(ssk);
3659 list_add_tail(&subflow->node, &msk->join_list);
3660 __set_bit(MPTCP_FLUSH_JOIN_LIST, &msk->cb_flags);
3661 }
3662 mptcp_data_unlock(parent);
3663
3664 if (!ret) {
3665 err_prohibited:
3666 subflow->reset_reason = MPTCP_RST_EPROHIBIT;
3667 return false;
3668 }
3669
3670 return true;
3671 }
3672
mptcp_shutdown(struct sock * sk,int how)3673 static void mptcp_shutdown(struct sock *sk, int how)
3674 {
3675 pr_debug("sk=%p, how=%d\n", sk, how);
3676
3677 if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk))
3678 __mptcp_wr_shutdown(sk);
3679 }
3680
mptcp_forward_alloc_get(const struct sock * sk)3681 static int mptcp_forward_alloc_get(const struct sock *sk)
3682 {
3683 return READ_ONCE(sk->sk_forward_alloc) +
3684 READ_ONCE(mptcp_sk(sk)->rmem_fwd_alloc);
3685 }
3686
mptcp_ioctl_outq(const struct mptcp_sock * msk,u64 v)3687 static int mptcp_ioctl_outq(const struct mptcp_sock *msk, u64 v)
3688 {
3689 const struct sock *sk = (void *)msk;
3690 u64 delta;
3691
3692 if (sk->sk_state == TCP_LISTEN)
3693 return -EINVAL;
3694
3695 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
3696 return 0;
3697
3698 delta = msk->write_seq - v;
3699 if (__mptcp_check_fallback(msk) && msk->first) {
3700 struct tcp_sock *tp = tcp_sk(msk->first);
3701
3702 /* the first subflow is disconnected after close - see
3703 * __mptcp_close_ssk(). tcp_disconnect() moves the write_seq
3704 * so ignore that status, too.
3705 */
3706 if (!((1 << msk->first->sk_state) &
3707 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE)))
3708 delta += READ_ONCE(tp->write_seq) - tp->snd_una;
3709 }
3710 if (delta > INT_MAX)
3711 delta = INT_MAX;
3712
3713 return (int)delta;
3714 }
3715
mptcp_ioctl(struct sock * sk,int cmd,int * karg)3716 static int mptcp_ioctl(struct sock *sk, int cmd, int *karg)
3717 {
3718 struct mptcp_sock *msk = mptcp_sk(sk);
3719 bool slow;
3720
3721 switch (cmd) {
3722 case SIOCINQ:
3723 if (sk->sk_state == TCP_LISTEN)
3724 return -EINVAL;
3725
3726 lock_sock(sk);
3727 __mptcp_move_skbs(msk);
3728 *karg = mptcp_inq_hint(sk);
3729 release_sock(sk);
3730 break;
3731 case SIOCOUTQ:
3732 slow = lock_sock_fast(sk);
3733 *karg = mptcp_ioctl_outq(msk, READ_ONCE(msk->snd_una));
3734 unlock_sock_fast(sk, slow);
3735 break;
3736 case SIOCOUTQNSD:
3737 slow = lock_sock_fast(sk);
3738 *karg = mptcp_ioctl_outq(msk, msk->snd_nxt);
3739 unlock_sock_fast(sk, slow);
3740 break;
3741 default:
3742 return -ENOIOCTLCMD;
3743 }
3744
3745 return 0;
3746 }
3747
mptcp_connect(struct sock * sk,struct sockaddr * uaddr,int addr_len)3748 static int mptcp_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
3749 {
3750 struct mptcp_subflow_context *subflow;
3751 struct mptcp_sock *msk = mptcp_sk(sk);
3752 int err = -EINVAL;
3753 struct sock *ssk;
3754
3755 ssk = __mptcp_nmpc_sk(msk);
3756 if (IS_ERR(ssk))
3757 return PTR_ERR(ssk);
3758
3759 mptcp_set_state(sk, TCP_SYN_SENT);
3760 subflow = mptcp_subflow_ctx(ssk);
3761 #ifdef CONFIG_TCP_MD5SIG
3762 /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
3763 * TCP option space.
3764 */
3765 if (rcu_access_pointer(tcp_sk(ssk)->md5sig_info))
3766 mptcp_subflow_early_fallback(msk, subflow);
3767 #endif
3768 if (subflow->request_mptcp) {
3769 if (mptcp_active_should_disable(sk)) {
3770 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_MPCAPABLEACTIVEDISABLED);
3771 mptcp_subflow_early_fallback(msk, subflow);
3772 } else if (mptcp_token_new_connect(ssk) < 0) {
3773 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_TOKENFALLBACKINIT);
3774 mptcp_subflow_early_fallback(msk, subflow);
3775 }
3776 }
3777
3778 WRITE_ONCE(msk->write_seq, subflow->idsn);
3779 WRITE_ONCE(msk->snd_nxt, subflow->idsn);
3780 WRITE_ONCE(msk->snd_una, subflow->idsn);
3781 if (likely(!__mptcp_check_fallback(msk)))
3782 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVE);
3783
3784 /* if reaching here via the fastopen/sendmsg path, the caller already
3785 * acquired the subflow socket lock, too.
3786 */
3787 if (!msk->fastopening)
3788 lock_sock(ssk);
3789
3790 /* the following mirrors closely a very small chunk of code from
3791 * __inet_stream_connect()
3792 */
3793 if (ssk->sk_state != TCP_CLOSE)
3794 goto out;
3795
3796 if (BPF_CGROUP_PRE_CONNECT_ENABLED(ssk)) {
3797 err = ssk->sk_prot->pre_connect(ssk, uaddr, addr_len);
3798 if (err)
3799 goto out;
3800 }
3801
3802 err = ssk->sk_prot->connect(ssk, uaddr, addr_len);
3803 if (err < 0)
3804 goto out;
3805
3806 inet_assign_bit(DEFER_CONNECT, sk, inet_test_bit(DEFER_CONNECT, ssk));
3807
3808 out:
3809 if (!msk->fastopening)
3810 release_sock(ssk);
3811
3812 /* on successful connect, the msk state will be moved to established by
3813 * subflow_finish_connect()
3814 */
3815 if (unlikely(err)) {
3816 /* avoid leaving a dangling token in an unconnected socket */
3817 mptcp_token_destroy(msk);
3818 mptcp_set_state(sk, TCP_CLOSE);
3819 return err;
3820 }
3821
3822 mptcp_copy_inaddrs(sk, ssk);
3823 return 0;
3824 }
3825
3826 static struct proto mptcp_prot = {
3827 .name = "MPTCP",
3828 .owner = THIS_MODULE,
3829 .init = mptcp_init_sock,
3830 .connect = mptcp_connect,
3831 .disconnect = mptcp_disconnect,
3832 .close = mptcp_close,
3833 .setsockopt = mptcp_setsockopt,
3834 .getsockopt = mptcp_getsockopt,
3835 .shutdown = mptcp_shutdown,
3836 .destroy = mptcp_destroy,
3837 .sendmsg = mptcp_sendmsg,
3838 .ioctl = mptcp_ioctl,
3839 .recvmsg = mptcp_recvmsg,
3840 .release_cb = mptcp_release_cb,
3841 .hash = mptcp_hash,
3842 .unhash = mptcp_unhash,
3843 .get_port = mptcp_get_port,
3844 .forward_alloc_get = mptcp_forward_alloc_get,
3845 .stream_memory_free = mptcp_stream_memory_free,
3846 .sockets_allocated = &mptcp_sockets_allocated,
3847
3848 .memory_allocated = &tcp_memory_allocated,
3849 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc,
3850
3851 .memory_pressure = &tcp_memory_pressure,
3852 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
3853 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
3854 .sysctl_mem = sysctl_tcp_mem,
3855 .obj_size = sizeof(struct mptcp_sock),
3856 .slab_flags = SLAB_TYPESAFE_BY_RCU,
3857 .no_autobind = true,
3858 };
3859
mptcp_bind(struct socket * sock,struct sockaddr * uaddr,int addr_len)3860 static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
3861 {
3862 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3863 struct sock *ssk, *sk = sock->sk;
3864 int err = -EINVAL;
3865
3866 lock_sock(sk);
3867 ssk = __mptcp_nmpc_sk(msk);
3868 if (IS_ERR(ssk)) {
3869 err = PTR_ERR(ssk);
3870 goto unlock;
3871 }
3872
3873 if (sk->sk_family == AF_INET)
3874 err = inet_bind_sk(ssk, uaddr, addr_len);
3875 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
3876 else if (sk->sk_family == AF_INET6)
3877 err = inet6_bind_sk(ssk, uaddr, addr_len);
3878 #endif
3879 if (!err)
3880 mptcp_copy_inaddrs(sk, ssk);
3881
3882 unlock:
3883 release_sock(sk);
3884 return err;
3885 }
3886
mptcp_listen(struct socket * sock,int backlog)3887 static int mptcp_listen(struct socket *sock, int backlog)
3888 {
3889 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3890 struct sock *sk = sock->sk;
3891 struct sock *ssk;
3892 int err;
3893
3894 pr_debug("msk=%p\n", msk);
3895
3896 lock_sock(sk);
3897
3898 err = -EINVAL;
3899 if (sock->state != SS_UNCONNECTED || sock->type != SOCK_STREAM)
3900 goto unlock;
3901
3902 ssk = __mptcp_nmpc_sk(msk);
3903 if (IS_ERR(ssk)) {
3904 err = PTR_ERR(ssk);
3905 goto unlock;
3906 }
3907
3908 mptcp_set_state(sk, TCP_LISTEN);
3909 sock_set_flag(sk, SOCK_RCU_FREE);
3910
3911 lock_sock(ssk);
3912 err = __inet_listen_sk(ssk, backlog);
3913 release_sock(ssk);
3914 mptcp_set_state(sk, inet_sk_state_load(ssk));
3915
3916 if (!err) {
3917 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
3918 mptcp_copy_inaddrs(sk, ssk);
3919 mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CREATED);
3920 }
3921
3922 unlock:
3923 release_sock(sk);
3924 return err;
3925 }
3926
mptcp_stream_accept(struct socket * sock,struct socket * newsock,struct proto_accept_arg * arg)3927 static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
3928 struct proto_accept_arg *arg)
3929 {
3930 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3931 struct sock *ssk, *newsk;
3932
3933 pr_debug("msk=%p\n", msk);
3934
3935 /* Buggy applications can call accept on socket states other then LISTEN
3936 * but no need to allocate the first subflow just to error out.
3937 */
3938 ssk = READ_ONCE(msk->first);
3939 if (!ssk)
3940 return -EINVAL;
3941
3942 pr_debug("ssk=%p, listener=%p\n", ssk, mptcp_subflow_ctx(ssk));
3943 newsk = inet_csk_accept(ssk, arg);
3944 if (!newsk)
3945 return arg->err;
3946
3947 pr_debug("newsk=%p, subflow is mptcp=%d\n", newsk, sk_is_mptcp(newsk));
3948 if (sk_is_mptcp(newsk)) {
3949 struct mptcp_subflow_context *subflow;
3950 struct sock *new_mptcp_sock;
3951
3952 subflow = mptcp_subflow_ctx(newsk);
3953 new_mptcp_sock = subflow->conn;
3954
3955 /* is_mptcp should be false if subflow->conn is missing, see
3956 * subflow_syn_recv_sock()
3957 */
3958 if (WARN_ON_ONCE(!new_mptcp_sock)) {
3959 tcp_sk(newsk)->is_mptcp = 0;
3960 goto tcpfallback;
3961 }
3962
3963 newsk = new_mptcp_sock;
3964 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_MPCAPABLEPASSIVEACK);
3965
3966 newsk->sk_kern_sock = arg->kern;
3967 lock_sock(newsk);
3968 __inet_accept(sock, newsock, newsk);
3969
3970 set_bit(SOCK_CUSTOM_SOCKOPT, &newsock->flags);
3971 msk = mptcp_sk(newsk);
3972 msk->in_accept_queue = 0;
3973
3974 /* set ssk->sk_socket of accept()ed flows to mptcp socket.
3975 * This is needed so NOSPACE flag can be set from tcp stack.
3976 */
3977 mptcp_for_each_subflow(msk, subflow) {
3978 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3979
3980 if (!ssk->sk_socket)
3981 mptcp_sock_graft(ssk, newsock);
3982 }
3983
3984 /* Do late cleanup for the first subflow as necessary. Also
3985 * deal with bad peers not doing a complete shutdown.
3986 */
3987 if (unlikely(inet_sk_state_load(msk->first) == TCP_CLOSE)) {
3988 __mptcp_close_ssk(newsk, msk->first,
3989 mptcp_subflow_ctx(msk->first), 0);
3990 if (unlikely(list_is_singular(&msk->conn_list)))
3991 mptcp_set_state(newsk, TCP_CLOSE);
3992 }
3993 } else {
3994 tcpfallback:
3995 newsk->sk_kern_sock = arg->kern;
3996 lock_sock(newsk);
3997 __inet_accept(sock, newsock, newsk);
3998 /* we are being invoked after accepting a non-mp-capable
3999 * flow: sk is a tcp_sk, not an mptcp one.
4000 *
4001 * Hand the socket over to tcp so all further socket ops
4002 * bypass mptcp.
4003 */
4004 WRITE_ONCE(newsock->sk->sk_socket->ops,
4005 mptcp_fallback_tcp_ops(newsock->sk));
4006 }
4007 release_sock(newsk);
4008
4009 return 0;
4010 }
4011
mptcp_check_writeable(struct mptcp_sock * msk)4012 static __poll_t mptcp_check_writeable(struct mptcp_sock *msk)
4013 {
4014 struct sock *sk = (struct sock *)msk;
4015
4016 if (__mptcp_stream_is_writeable(sk, 1))
4017 return EPOLLOUT | EPOLLWRNORM;
4018
4019 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
4020 smp_mb__after_atomic(); /* NOSPACE is changed by mptcp_write_space() */
4021 if (__mptcp_stream_is_writeable(sk, 1))
4022 return EPOLLOUT | EPOLLWRNORM;
4023
4024 return 0;
4025 }
4026
mptcp_poll(struct file * file,struct socket * sock,struct poll_table_struct * wait)4027 static __poll_t mptcp_poll(struct file *file, struct socket *sock,
4028 struct poll_table_struct *wait)
4029 {
4030 struct sock *sk = sock->sk;
4031 struct mptcp_sock *msk;
4032 __poll_t mask = 0;
4033 u8 shutdown;
4034 int state;
4035
4036 msk = mptcp_sk(sk);
4037 sock_poll_wait(file, sock, wait);
4038
4039 state = inet_sk_state_load(sk);
4040 pr_debug("msk=%p state=%d flags=%lx\n", msk, state, msk->flags);
4041 if (state == TCP_LISTEN) {
4042 struct sock *ssk = READ_ONCE(msk->first);
4043
4044 if (WARN_ON_ONCE(!ssk))
4045 return 0;
4046
4047 return inet_csk_listen_poll(ssk);
4048 }
4049
4050 shutdown = READ_ONCE(sk->sk_shutdown);
4051 if (shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
4052 mask |= EPOLLHUP;
4053 if (shutdown & RCV_SHUTDOWN)
4054 mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
4055
4056 if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) {
4057 mask |= mptcp_check_readable(sk);
4058 if (shutdown & SEND_SHUTDOWN)
4059 mask |= EPOLLOUT | EPOLLWRNORM;
4060 else
4061 mask |= mptcp_check_writeable(msk);
4062 } else if (state == TCP_SYN_SENT &&
4063 inet_test_bit(DEFER_CONNECT, sk)) {
4064 /* cf tcp_poll() note about TFO */
4065 mask |= EPOLLOUT | EPOLLWRNORM;
4066 }
4067
4068 /* This barrier is coupled with smp_wmb() in __mptcp_error_report() */
4069 smp_rmb();
4070 if (READ_ONCE(sk->sk_err))
4071 mask |= EPOLLERR;
4072
4073 return mask;
4074 }
4075
4076 static const struct proto_ops mptcp_stream_ops = {
4077 .family = PF_INET,
4078 .owner = THIS_MODULE,
4079 .release = inet_release,
4080 .bind = mptcp_bind,
4081 .connect = inet_stream_connect,
4082 .socketpair = sock_no_socketpair,
4083 .accept = mptcp_stream_accept,
4084 .getname = inet_getname,
4085 .poll = mptcp_poll,
4086 .ioctl = inet_ioctl,
4087 .gettstamp = sock_gettstamp,
4088 .listen = mptcp_listen,
4089 .shutdown = inet_shutdown,
4090 .setsockopt = sock_common_setsockopt,
4091 .getsockopt = sock_common_getsockopt,
4092 .sendmsg = inet_sendmsg,
4093 .recvmsg = inet_recvmsg,
4094 .mmap = sock_no_mmap,
4095 .set_rcvlowat = mptcp_set_rcvlowat,
4096 };
4097
4098 static struct inet_protosw mptcp_protosw = {
4099 .type = SOCK_STREAM,
4100 .protocol = IPPROTO_MPTCP,
4101 .prot = &mptcp_prot,
4102 .ops = &mptcp_stream_ops,
4103 .flags = INET_PROTOSW_ICSK,
4104 };
4105
mptcp_napi_poll(struct napi_struct * napi,int budget)4106 static int mptcp_napi_poll(struct napi_struct *napi, int budget)
4107 {
4108 struct mptcp_delegated_action *delegated;
4109 struct mptcp_subflow_context *subflow;
4110 int work_done = 0;
4111
4112 delegated = container_of(napi, struct mptcp_delegated_action, napi);
4113 while ((subflow = mptcp_subflow_delegated_next(delegated)) != NULL) {
4114 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
4115
4116 bh_lock_sock_nested(ssk);
4117 if (!sock_owned_by_user(ssk)) {
4118 mptcp_subflow_process_delegated(ssk, xchg(&subflow->delegated_status, 0));
4119 } else {
4120 /* tcp_release_cb_override already processed
4121 * the action or will do at next release_sock().
4122 * In both case must dequeue the subflow here - on the same
4123 * CPU that scheduled it.
4124 */
4125 smp_wmb();
4126 clear_bit(MPTCP_DELEGATE_SCHEDULED, &subflow->delegated_status);
4127 }
4128 bh_unlock_sock(ssk);
4129 sock_put(ssk);
4130
4131 if (++work_done == budget)
4132 return budget;
4133 }
4134
4135 /* always provide a 0 'work_done' argument, so that napi_complete_done
4136 * will not try accessing the NULL napi->dev ptr
4137 */
4138 napi_complete_done(napi, 0);
4139 return work_done;
4140 }
4141
mptcp_proto_init(void)4142 void __init mptcp_proto_init(void)
4143 {
4144 struct mptcp_delegated_action *delegated;
4145 int cpu;
4146
4147 mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo;
4148
4149 if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL))
4150 panic("Failed to allocate MPTCP pcpu counter\n");
4151
4152 mptcp_napi_dev = alloc_netdev_dummy(0);
4153 if (!mptcp_napi_dev)
4154 panic("Failed to allocate MPTCP dummy netdev\n");
4155 for_each_possible_cpu(cpu) {
4156 delegated = per_cpu_ptr(&mptcp_delegated_actions, cpu);
4157 INIT_LIST_HEAD(&delegated->head);
4158 netif_napi_add_tx(mptcp_napi_dev, &delegated->napi,
4159 mptcp_napi_poll);
4160 napi_enable(&delegated->napi);
4161 }
4162
4163 mptcp_subflow_init();
4164 mptcp_pm_init();
4165 mptcp_sched_init();
4166 mptcp_token_init();
4167
4168 if (proto_register(&mptcp_prot, 1) != 0)
4169 panic("Failed to register MPTCP proto.\n");
4170
4171 inet_register_protosw(&mptcp_protosw);
4172
4173 BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb));
4174 }
4175
4176 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
4177 static const struct proto_ops mptcp_v6_stream_ops = {
4178 .family = PF_INET6,
4179 .owner = THIS_MODULE,
4180 .release = inet6_release,
4181 .bind = mptcp_bind,
4182 .connect = inet_stream_connect,
4183 .socketpair = sock_no_socketpair,
4184 .accept = mptcp_stream_accept,
4185 .getname = inet6_getname,
4186 .poll = mptcp_poll,
4187 .ioctl = inet6_ioctl,
4188 .gettstamp = sock_gettstamp,
4189 .listen = mptcp_listen,
4190 .shutdown = inet_shutdown,
4191 .setsockopt = sock_common_setsockopt,
4192 .getsockopt = sock_common_getsockopt,
4193 .sendmsg = inet6_sendmsg,
4194 .recvmsg = inet6_recvmsg,
4195 .mmap = sock_no_mmap,
4196 #ifdef CONFIG_COMPAT
4197 .compat_ioctl = inet6_compat_ioctl,
4198 #endif
4199 .set_rcvlowat = mptcp_set_rcvlowat,
4200 };
4201
4202 static struct proto mptcp_v6_prot;
4203
4204 static struct inet_protosw mptcp_v6_protosw = {
4205 .type = SOCK_STREAM,
4206 .protocol = IPPROTO_MPTCP,
4207 .prot = &mptcp_v6_prot,
4208 .ops = &mptcp_v6_stream_ops,
4209 .flags = INET_PROTOSW_ICSK,
4210 };
4211
mptcp_proto_v6_init(void)4212 int __init mptcp_proto_v6_init(void)
4213 {
4214 int err;
4215
4216 mptcp_v6_prot = mptcp_prot;
4217 strscpy(mptcp_v6_prot.name, "MPTCPv6", sizeof(mptcp_v6_prot.name));
4218 mptcp_v6_prot.slab = NULL;
4219 mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock);
4220 mptcp_v6_prot.ipv6_pinfo_offset = offsetof(struct mptcp6_sock, np);
4221
4222 err = proto_register(&mptcp_v6_prot, 1);
4223 if (err)
4224 return err;
4225
4226 err = inet6_register_protosw(&mptcp_v6_protosw);
4227 if (err)
4228 proto_unregister(&mptcp_v6_prot);
4229
4230 return err;
4231 }
4232 #endif
4233