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/aligned_data.h>
15 #include <net/rps.h>
16 #include <net/sock.h>
17 #include <net/inet_common.h>
18 #include <net/inet_hashtables.h>
19 #include <net/protocol.h>
20 #include <net/tcp_states.h>
21 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
22 #include <net/transp_v6.h>
23 #endif
24 #include <net/mptcp.h>
25 #include <net/hotdata.h>
26 #include <net/xfrm.h>
27 #include <asm/ioctls.h>
28 #include "protocol.h"
29 #include "mib.h"
30
31 #define CREATE_TRACE_POINTS
32 #include <trace/events/mptcp.h>
33
34 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
35 struct mptcp6_sock {
36 struct mptcp_sock msk;
37 struct ipv6_pinfo np;
38 };
39 #endif
40
41 enum {
42 MPTCP_CMSG_TS = BIT(0),
43 MPTCP_CMSG_INQ = BIT(1),
44 };
45
46 static struct percpu_counter mptcp_sockets_allocated ____cacheline_aligned_in_smp;
47
48 static void __mptcp_destroy_sock(struct sock *sk);
49 static void mptcp_check_send_data_fin(struct sock *sk);
50
51 DEFINE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions) = {
52 .bh_lock = INIT_LOCAL_LOCK(bh_lock),
53 };
54 static struct net_device *mptcp_napi_dev;
55
56 /* Returns end sequence number of the receiver's advertised window */
mptcp_wnd_end(const struct mptcp_sock * msk)57 static u64 mptcp_wnd_end(const struct mptcp_sock *msk)
58 {
59 return READ_ONCE(msk->wnd_end);
60 }
61
mptcp_fallback_tcp_ops(const struct sock * sk)62 static const struct proto_ops *mptcp_fallback_tcp_ops(const struct sock *sk)
63 {
64 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
65 if (sk->sk_prot == &tcpv6_prot)
66 return &inet6_stream_ops;
67 #endif
68 WARN_ON_ONCE(sk->sk_prot != &tcp_prot);
69 return &inet_stream_ops;
70 }
71
__mptcp_try_fallback(struct mptcp_sock * msk,int fb_mib)72 bool __mptcp_try_fallback(struct mptcp_sock *msk, int fb_mib)
73 {
74 struct net *net = sock_net((struct sock *)msk);
75
76 if (__mptcp_check_fallback(msk))
77 return true;
78
79 spin_lock_bh(&msk->fallback_lock);
80 if (!msk->allow_infinite_fallback) {
81 spin_unlock_bh(&msk->fallback_lock);
82 return false;
83 }
84
85 msk->allow_subflows = false;
86 set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
87 __MPTCP_INC_STATS(net, fb_mib);
88 spin_unlock_bh(&msk->fallback_lock);
89 return true;
90 }
91
__mptcp_socket_create(struct mptcp_sock * msk)92 static int __mptcp_socket_create(struct mptcp_sock *msk)
93 {
94 struct mptcp_subflow_context *subflow;
95 struct sock *sk = (struct sock *)msk;
96 struct socket *ssock;
97 int err;
98
99 err = mptcp_subflow_create_socket(sk, sk->sk_family, &ssock);
100 if (err)
101 return err;
102
103 msk->scaling_ratio = tcp_sk(ssock->sk)->scaling_ratio;
104 WRITE_ONCE(msk->first, ssock->sk);
105 subflow = mptcp_subflow_ctx(ssock->sk);
106 list_add(&subflow->node, &msk->conn_list);
107 sock_hold(ssock->sk);
108 subflow->request_mptcp = 1;
109 subflow->subflow_id = msk->subflow_id++;
110
111 /* This is the first subflow, always with id 0 */
112 WRITE_ONCE(subflow->local_id, 0);
113 mptcp_sock_graft(msk->first, sk->sk_socket);
114 iput(SOCK_INODE(ssock));
115
116 return 0;
117 }
118
119 /* If the MPC handshake is not started, returns the first subflow,
120 * eventually allocating it.
121 */
__mptcp_nmpc_sk(struct mptcp_sock * msk)122 struct sock *__mptcp_nmpc_sk(struct mptcp_sock *msk)
123 {
124 struct sock *sk = (struct sock *)msk;
125 int ret;
126
127 if (!((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
128 return ERR_PTR(-EINVAL);
129
130 if (!msk->first) {
131 ret = __mptcp_socket_create(msk);
132 if (ret)
133 return ERR_PTR(ret);
134 }
135
136 return msk->first;
137 }
138
mptcp_drop(struct sock * sk,struct sk_buff * skb)139 static void mptcp_drop(struct sock *sk, struct sk_buff *skb)
140 {
141 sk_drops_skbadd(sk, skb);
142 __kfree_skb(skb);
143 }
144
__mptcp_try_coalesce(struct sock * sk,struct sk_buff * to,struct sk_buff * from,bool * fragstolen,int * delta)145 static bool __mptcp_try_coalesce(struct sock *sk, struct sk_buff *to,
146 struct sk_buff *from, bool *fragstolen,
147 int *delta)
148 {
149 int limit = READ_ONCE(sk->sk_rcvbuf);
150
151 if (unlikely(MPTCP_SKB_CB(to)->cant_coalesce) ||
152 MPTCP_SKB_CB(from)->offset ||
153 ((to->len + from->len) > (limit >> 3)) ||
154 !skb_try_coalesce(to, from, fragstolen, delta))
155 return false;
156
157 pr_debug("colesced seq %llx into %llx new len %d new end seq %llx\n",
158 MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq,
159 to->len, MPTCP_SKB_CB(from)->end_seq);
160 MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq;
161 return true;
162 }
163
mptcp_try_coalesce(struct sock * sk,struct sk_buff * to,struct sk_buff * from)164 static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to,
165 struct sk_buff *from)
166 {
167 bool fragstolen;
168 int delta;
169
170 if (!__mptcp_try_coalesce(sk, to, from, &fragstolen, &delta))
171 return false;
172
173 /* note the fwd memory can reach a negative value after accounting
174 * for the delta, but the later skb free will restore a non
175 * negative one
176 */
177 atomic_add(delta, &sk->sk_rmem_alloc);
178 sk_mem_charge(sk, delta);
179 kfree_skb_partial(from, fragstolen);
180
181 return true;
182 }
183
mptcp_ooo_try_coalesce(struct mptcp_sock * msk,struct sk_buff * to,struct sk_buff * from)184 static bool mptcp_ooo_try_coalesce(struct mptcp_sock *msk, struct sk_buff *to,
185 struct sk_buff *from)
186 {
187 if (MPTCP_SKB_CB(from)->map_seq != MPTCP_SKB_CB(to)->end_seq)
188 return false;
189
190 return mptcp_try_coalesce((struct sock *)msk, to, from);
191 }
192
193 /* "inspired" by tcp_rcvbuf_grow(), main difference:
194 * - mptcp does not maintain a msk-level window clamp
195 * - returns true when the receive buffer is actually updated
196 */
mptcp_rcvbuf_grow(struct sock * sk)197 static bool mptcp_rcvbuf_grow(struct sock *sk)
198 {
199 struct mptcp_sock *msk = mptcp_sk(sk);
200 const struct net *net = sock_net(sk);
201 int rcvwin, rcvbuf, cap;
202
203 if (!READ_ONCE(net->ipv4.sysctl_tcp_moderate_rcvbuf) ||
204 (sk->sk_userlocks & SOCK_RCVBUF_LOCK))
205 return false;
206
207 rcvwin = msk->rcvq_space.space << 1;
208
209 if (!RB_EMPTY_ROOT(&msk->out_of_order_queue))
210 rcvwin += MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq - msk->ack_seq;
211
212 cap = READ_ONCE(net->ipv4.sysctl_tcp_rmem[2]);
213
214 rcvbuf = min_t(u32, mptcp_space_from_win(sk, rcvwin), cap);
215 if (rcvbuf > sk->sk_rcvbuf) {
216 WRITE_ONCE(sk->sk_rcvbuf, rcvbuf);
217 return true;
218 }
219 return false;
220 }
221
222 /* "inspired" by tcp_data_queue_ofo(), main differences:
223 * - use mptcp seqs
224 * - don't cope with sacks
225 */
mptcp_data_queue_ofo(struct mptcp_sock * msk,struct sk_buff * skb)226 static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb)
227 {
228 struct sock *sk = (struct sock *)msk;
229 struct rb_node **p, *parent;
230 u64 seq, end_seq, max_seq;
231 struct sk_buff *skb1;
232
233 seq = MPTCP_SKB_CB(skb)->map_seq;
234 end_seq = MPTCP_SKB_CB(skb)->end_seq;
235 max_seq = atomic64_read(&msk->rcv_wnd_sent);
236
237 pr_debug("msk=%p seq=%llx limit=%llx empty=%d\n", msk, seq, max_seq,
238 RB_EMPTY_ROOT(&msk->out_of_order_queue));
239 if (after64(end_seq, max_seq)) {
240 /* out of window */
241 mptcp_drop(sk, skb);
242 pr_debug("oow by %lld, rcv_wnd_sent %llu\n",
243 (unsigned long long)end_seq - (unsigned long)max_seq,
244 (unsigned long long)atomic64_read(&msk->rcv_wnd_sent));
245 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_NODSSWINDOW);
246 return;
247 }
248
249 p = &msk->out_of_order_queue.rb_node;
250 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUE);
251 if (RB_EMPTY_ROOT(&msk->out_of_order_queue)) {
252 rb_link_node(&skb->rbnode, NULL, p);
253 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
254 msk->ooo_last_skb = skb;
255 goto end;
256 }
257
258 /* with 2 subflows, adding at end of ooo queue is quite likely
259 * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup.
260 */
261 if (mptcp_ooo_try_coalesce(msk, msk->ooo_last_skb, skb)) {
262 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
263 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
264 return;
265 }
266
267 /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */
268 if (!before64(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) {
269 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
270 parent = &msk->ooo_last_skb->rbnode;
271 p = &parent->rb_right;
272 goto insert;
273 }
274
275 /* Find place to insert this segment. Handle overlaps on the way. */
276 parent = NULL;
277 while (*p) {
278 parent = *p;
279 skb1 = rb_to_skb(parent);
280 if (before64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
281 p = &parent->rb_left;
282 continue;
283 }
284 if (before64(seq, MPTCP_SKB_CB(skb1)->end_seq)) {
285 if (!after64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) {
286 /* All the bits are present. Drop. */
287 mptcp_drop(sk, skb);
288 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
289 return;
290 }
291 if (after64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
292 /* partial overlap:
293 * | skb |
294 * | skb1 |
295 * continue traversing
296 */
297 } else {
298 /* skb's seq == skb1's seq and skb covers skb1.
299 * Replace skb1 with skb.
300 */
301 rb_replace_node(&skb1->rbnode, &skb->rbnode,
302 &msk->out_of_order_queue);
303 mptcp_drop(sk, skb1);
304 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
305 goto merge_right;
306 }
307 } else if (mptcp_ooo_try_coalesce(msk, skb1, skb)) {
308 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
309 return;
310 }
311 p = &parent->rb_right;
312 }
313
314 insert:
315 /* Insert segment into RB tree. */
316 rb_link_node(&skb->rbnode, parent, p);
317 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
318
319 merge_right:
320 /* Remove other segments covered by skb. */
321 while ((skb1 = skb_rb_next(skb)) != NULL) {
322 if (before64(end_seq, MPTCP_SKB_CB(skb1)->end_seq))
323 break;
324 rb_erase(&skb1->rbnode, &msk->out_of_order_queue);
325 mptcp_drop(sk, skb1);
326 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
327 }
328 /* If there is no skb after us, we are the last_skb ! */
329 if (!skb1)
330 msk->ooo_last_skb = skb;
331
332 end:
333 skb_condense(skb);
334 skb_set_owner_r(skb, sk);
335 /* do not grow rcvbuf for not-yet-accepted or orphaned sockets. */
336 if (sk->sk_socket)
337 mptcp_rcvbuf_grow(sk);
338 }
339
mptcp_init_skb(struct sock * ssk,struct sk_buff * skb,int offset,int copy_len)340 static void mptcp_init_skb(struct sock *ssk, struct sk_buff *skb, int offset,
341 int copy_len)
342 {
343 const struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
344 bool has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp;
345
346 /* the skb map_seq accounts for the skb offset:
347 * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq
348 * value
349 */
350 MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow);
351 MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len;
352 MPTCP_SKB_CB(skb)->offset = offset;
353 MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp;
354 MPTCP_SKB_CB(skb)->cant_coalesce = 0;
355
356 __skb_unlink(skb, &ssk->sk_receive_queue);
357
358 skb_ext_reset(skb);
359 skb_dst_drop(skb);
360 }
361
__mptcp_move_skb(struct sock * sk,struct sk_buff * skb)362 static bool __mptcp_move_skb(struct sock *sk, struct sk_buff *skb)
363 {
364 u64 copy_len = MPTCP_SKB_CB(skb)->end_seq - MPTCP_SKB_CB(skb)->map_seq;
365 struct mptcp_sock *msk = mptcp_sk(sk);
366 struct sk_buff *tail;
367
368 /* try to fetch required memory from subflow */
369 if (!sk_rmem_schedule(sk, skb, skb->truesize)) {
370 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED);
371 goto drop;
372 }
373
374 if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) {
375 /* in sequence */
376 msk->bytes_received += copy_len;
377 WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len);
378 tail = skb_peek_tail(&sk->sk_receive_queue);
379 if (tail && mptcp_try_coalesce(sk, tail, skb))
380 return true;
381
382 skb_set_owner_r(skb, sk);
383 __skb_queue_tail(&sk->sk_receive_queue, skb);
384 return true;
385 } else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) {
386 mptcp_data_queue_ofo(msk, skb);
387 return false;
388 }
389
390 /* old data, keep it simple and drop the whole pkt, sender
391 * will retransmit as needed, if needed.
392 */
393 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
394 drop:
395 mptcp_drop(sk, skb);
396 return false;
397 }
398
mptcp_stop_rtx_timer(struct sock * sk)399 static void mptcp_stop_rtx_timer(struct sock *sk)
400 {
401 struct inet_connection_sock *icsk = inet_csk(sk);
402
403 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
404 mptcp_sk(sk)->timer_ival = 0;
405 }
406
mptcp_close_wake_up(struct sock * sk)407 static void mptcp_close_wake_up(struct sock *sk)
408 {
409 if (sock_flag(sk, SOCK_DEAD))
410 return;
411
412 sk->sk_state_change(sk);
413 if (sk->sk_shutdown == SHUTDOWN_MASK ||
414 sk->sk_state == TCP_CLOSE)
415 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
416 else
417 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
418 }
419
mptcp_shutdown_subflows(struct mptcp_sock * msk)420 static void mptcp_shutdown_subflows(struct mptcp_sock *msk)
421 {
422 struct mptcp_subflow_context *subflow;
423
424 mptcp_for_each_subflow(msk, subflow) {
425 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
426 bool slow;
427
428 slow = lock_sock_fast(ssk);
429 tcp_shutdown(ssk, SEND_SHUTDOWN);
430 unlock_sock_fast(ssk, slow);
431 }
432 }
433
434 /* called under the msk socket lock */
mptcp_pending_data_fin_ack(struct sock * sk)435 static bool mptcp_pending_data_fin_ack(struct sock *sk)
436 {
437 struct mptcp_sock *msk = mptcp_sk(sk);
438
439 return ((1 << sk->sk_state) &
440 (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) &&
441 msk->write_seq == READ_ONCE(msk->snd_una);
442 }
443
mptcp_check_data_fin_ack(struct sock * sk)444 static void mptcp_check_data_fin_ack(struct sock *sk)
445 {
446 struct mptcp_sock *msk = mptcp_sk(sk);
447
448 /* Look for an acknowledged DATA_FIN */
449 if (mptcp_pending_data_fin_ack(sk)) {
450 WRITE_ONCE(msk->snd_data_fin_enable, 0);
451
452 switch (sk->sk_state) {
453 case TCP_FIN_WAIT1:
454 mptcp_set_state(sk, TCP_FIN_WAIT2);
455 break;
456 case TCP_CLOSING:
457 case TCP_LAST_ACK:
458 mptcp_shutdown_subflows(msk);
459 mptcp_set_state(sk, TCP_CLOSE);
460 break;
461 }
462
463 mptcp_close_wake_up(sk);
464 }
465 }
466
467 /* can be called with no lock acquired */
mptcp_pending_data_fin(struct sock * sk,u64 * seq)468 static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq)
469 {
470 struct mptcp_sock *msk = mptcp_sk(sk);
471
472 if (READ_ONCE(msk->rcv_data_fin) &&
473 ((1 << inet_sk_state_load(sk)) &
474 (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) {
475 u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq);
476
477 if (READ_ONCE(msk->ack_seq) == rcv_data_fin_seq) {
478 if (seq)
479 *seq = rcv_data_fin_seq;
480
481 return true;
482 }
483 }
484
485 return false;
486 }
487
mptcp_set_datafin_timeout(struct sock * sk)488 static void mptcp_set_datafin_timeout(struct sock *sk)
489 {
490 struct inet_connection_sock *icsk = inet_csk(sk);
491 u32 retransmits;
492
493 retransmits = min_t(u32, icsk->icsk_retransmits,
494 ilog2(TCP_RTO_MAX / TCP_RTO_MIN));
495
496 mptcp_sk(sk)->timer_ival = TCP_RTO_MIN << retransmits;
497 }
498
__mptcp_set_timeout(struct sock * sk,long tout)499 static void __mptcp_set_timeout(struct sock *sk, long tout)
500 {
501 mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
502 }
503
mptcp_timeout_from_subflow(const struct mptcp_subflow_context * subflow)504 static long mptcp_timeout_from_subflow(const struct mptcp_subflow_context *subflow)
505 {
506 const struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
507
508 return inet_csk(ssk)->icsk_pending && !subflow->stale_count ?
509 icsk_timeout(inet_csk(ssk)) - jiffies : 0;
510 }
511
mptcp_set_timeout(struct sock * sk)512 static void mptcp_set_timeout(struct sock *sk)
513 {
514 struct mptcp_subflow_context *subflow;
515 long tout = 0;
516
517 mptcp_for_each_subflow(mptcp_sk(sk), subflow)
518 tout = max(tout, mptcp_timeout_from_subflow(subflow));
519 __mptcp_set_timeout(sk, tout);
520 }
521
tcp_can_send_ack(const struct sock * ssk)522 static inline bool tcp_can_send_ack(const struct sock *ssk)
523 {
524 return !((1 << inet_sk_state_load(ssk)) &
525 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE | TCPF_LISTEN));
526 }
527
__mptcp_subflow_send_ack(struct sock * ssk)528 void __mptcp_subflow_send_ack(struct sock *ssk)
529 {
530 if (tcp_can_send_ack(ssk))
531 tcp_send_ack(ssk);
532 }
533
mptcp_subflow_send_ack(struct sock * ssk)534 static void mptcp_subflow_send_ack(struct sock *ssk)
535 {
536 bool slow;
537
538 slow = lock_sock_fast(ssk);
539 __mptcp_subflow_send_ack(ssk);
540 unlock_sock_fast(ssk, slow);
541 }
542
mptcp_send_ack(struct mptcp_sock * msk)543 static void mptcp_send_ack(struct mptcp_sock *msk)
544 {
545 struct mptcp_subflow_context *subflow;
546
547 mptcp_for_each_subflow(msk, subflow)
548 mptcp_subflow_send_ack(mptcp_subflow_tcp_sock(subflow));
549 }
550
mptcp_subflow_cleanup_rbuf(struct sock * ssk,int copied)551 static void mptcp_subflow_cleanup_rbuf(struct sock *ssk, int copied)
552 {
553 bool slow;
554
555 slow = lock_sock_fast(ssk);
556 if (tcp_can_send_ack(ssk))
557 tcp_cleanup_rbuf(ssk, copied);
558 unlock_sock_fast(ssk, slow);
559 }
560
mptcp_subflow_could_cleanup(const struct sock * ssk,bool rx_empty)561 static bool mptcp_subflow_could_cleanup(const struct sock *ssk, bool rx_empty)
562 {
563 const struct inet_connection_sock *icsk = inet_csk(ssk);
564 u8 ack_pending = READ_ONCE(icsk->icsk_ack.pending);
565 const struct tcp_sock *tp = tcp_sk(ssk);
566
567 return (ack_pending & ICSK_ACK_SCHED) &&
568 ((READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->rcv_wup) >
569 READ_ONCE(icsk->icsk_ack.rcv_mss)) ||
570 (rx_empty && ack_pending &
571 (ICSK_ACK_PUSHED2 | ICSK_ACK_PUSHED)));
572 }
573
mptcp_cleanup_rbuf(struct mptcp_sock * msk,int copied)574 static void mptcp_cleanup_rbuf(struct mptcp_sock *msk, int copied)
575 {
576 int old_space = READ_ONCE(msk->old_wspace);
577 struct mptcp_subflow_context *subflow;
578 struct sock *sk = (struct sock *)msk;
579 int space = __mptcp_space(sk);
580 bool cleanup, rx_empty;
581
582 cleanup = (space > 0) && (space >= (old_space << 1)) && copied;
583 rx_empty = !sk_rmem_alloc_get(sk) && copied;
584
585 mptcp_for_each_subflow(msk, subflow) {
586 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
587
588 if (cleanup || mptcp_subflow_could_cleanup(ssk, rx_empty))
589 mptcp_subflow_cleanup_rbuf(ssk, copied);
590 }
591 }
592
mptcp_check_data_fin(struct sock * sk)593 static void mptcp_check_data_fin(struct sock *sk)
594 {
595 struct mptcp_sock *msk = mptcp_sk(sk);
596 u64 rcv_data_fin_seq;
597
598 /* Need to ack a DATA_FIN received from a peer while this side
599 * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2.
600 * msk->rcv_data_fin was set when parsing the incoming options
601 * at the subflow level and the msk lock was not held, so this
602 * is the first opportunity to act on the DATA_FIN and change
603 * the msk state.
604 *
605 * If we are caught up to the sequence number of the incoming
606 * DATA_FIN, send the DATA_ACK now and do state transition. If
607 * not caught up, do nothing and let the recv code send DATA_ACK
608 * when catching up.
609 */
610
611 if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) {
612 WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1);
613 WRITE_ONCE(msk->rcv_data_fin, 0);
614
615 WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | RCV_SHUTDOWN);
616 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
617
618 switch (sk->sk_state) {
619 case TCP_ESTABLISHED:
620 mptcp_set_state(sk, TCP_CLOSE_WAIT);
621 break;
622 case TCP_FIN_WAIT1:
623 mptcp_set_state(sk, TCP_CLOSING);
624 break;
625 case TCP_FIN_WAIT2:
626 mptcp_shutdown_subflows(msk);
627 mptcp_set_state(sk, TCP_CLOSE);
628 break;
629 default:
630 /* Other states not expected */
631 WARN_ON_ONCE(1);
632 break;
633 }
634
635 if (!__mptcp_check_fallback(msk))
636 mptcp_send_ack(msk);
637 mptcp_close_wake_up(sk);
638 }
639 }
640
mptcp_dss_corruption(struct mptcp_sock * msk,struct sock * ssk)641 static void mptcp_dss_corruption(struct mptcp_sock *msk, struct sock *ssk)
642 {
643 if (!mptcp_try_fallback(ssk, MPTCP_MIB_DSSCORRUPTIONFALLBACK)) {
644 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DSSCORRUPTIONRESET);
645 mptcp_subflow_reset(ssk);
646 }
647 }
648
__mptcp_move_skbs_from_subflow(struct mptcp_sock * msk,struct sock * ssk)649 static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
650 struct sock *ssk)
651 {
652 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
653 struct sock *sk = (struct sock *)msk;
654 bool more_data_avail;
655 struct tcp_sock *tp;
656 bool ret = false;
657
658 pr_debug("msk=%p ssk=%p\n", msk, ssk);
659 tp = tcp_sk(ssk);
660 do {
661 u32 map_remaining, offset;
662 u32 seq = tp->copied_seq;
663 struct sk_buff *skb;
664 bool fin;
665
666 if (sk_rmem_alloc_get(sk) > sk->sk_rcvbuf)
667 break;
668
669 /* try to move as much data as available */
670 map_remaining = subflow->map_data_len -
671 mptcp_subflow_get_map_offset(subflow);
672
673 skb = skb_peek(&ssk->sk_receive_queue);
674 if (unlikely(!skb))
675 break;
676
677 if (__mptcp_check_fallback(msk)) {
678 /* Under fallback skbs have no MPTCP extension and TCP could
679 * collapse them between the dummy map creation and the
680 * current dequeue. Be sure to adjust the map size.
681 */
682 map_remaining = skb->len;
683 subflow->map_data_len = skb->len;
684 }
685
686 offset = seq - TCP_SKB_CB(skb)->seq;
687 fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
688 if (fin)
689 seq++;
690
691 if (offset < skb->len) {
692 size_t len = skb->len - offset;
693
694 mptcp_init_skb(ssk, skb, offset, len);
695 skb_orphan(skb);
696 ret = __mptcp_move_skb(sk, skb) || ret;
697 seq += len;
698
699 if (unlikely(map_remaining < len)) {
700 DEBUG_NET_WARN_ON_ONCE(1);
701 mptcp_dss_corruption(msk, ssk);
702 }
703 } else {
704 if (unlikely(!fin)) {
705 DEBUG_NET_WARN_ON_ONCE(1);
706 mptcp_dss_corruption(msk, ssk);
707 }
708
709 sk_eat_skb(ssk, skb);
710 }
711
712 WRITE_ONCE(tp->copied_seq, seq);
713 more_data_avail = mptcp_subflow_data_available(ssk);
714
715 } while (more_data_avail);
716
717 if (ret)
718 msk->last_data_recv = tcp_jiffies32;
719 return ret;
720 }
721
__mptcp_ofo_queue(struct mptcp_sock * msk)722 static bool __mptcp_ofo_queue(struct mptcp_sock *msk)
723 {
724 struct sock *sk = (struct sock *)msk;
725 struct sk_buff *skb, *tail;
726 bool moved = false;
727 struct rb_node *p;
728 u64 end_seq;
729
730 p = rb_first(&msk->out_of_order_queue);
731 pr_debug("msk=%p empty=%d\n", msk, RB_EMPTY_ROOT(&msk->out_of_order_queue));
732 while (p) {
733 skb = rb_to_skb(p);
734 if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq))
735 break;
736
737 p = rb_next(p);
738 rb_erase(&skb->rbnode, &msk->out_of_order_queue);
739
740 if (unlikely(!after64(MPTCP_SKB_CB(skb)->end_seq,
741 msk->ack_seq))) {
742 mptcp_drop(sk, skb);
743 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
744 continue;
745 }
746
747 end_seq = MPTCP_SKB_CB(skb)->end_seq;
748 tail = skb_peek_tail(&sk->sk_receive_queue);
749 if (!tail || !mptcp_ooo_try_coalesce(msk, tail, skb)) {
750 int delta = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq;
751
752 /* skip overlapping data, if any */
753 pr_debug("uncoalesced seq=%llx ack seq=%llx delta=%d\n",
754 MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq,
755 delta);
756 MPTCP_SKB_CB(skb)->offset += delta;
757 MPTCP_SKB_CB(skb)->map_seq += delta;
758 __skb_queue_tail(&sk->sk_receive_queue, skb);
759 }
760 msk->bytes_received += end_seq - msk->ack_seq;
761 WRITE_ONCE(msk->ack_seq, end_seq);
762 moved = true;
763 }
764 return moved;
765 }
766
__mptcp_subflow_error_report(struct sock * sk,struct sock * ssk)767 static bool __mptcp_subflow_error_report(struct sock *sk, struct sock *ssk)
768 {
769 int err = sock_error(ssk);
770 int ssk_state;
771
772 if (!err)
773 return false;
774
775 /* only propagate errors on fallen-back sockets or
776 * on MPC connect
777 */
778 if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(mptcp_sk(sk)))
779 return false;
780
781 /* We need to propagate only transition to CLOSE state.
782 * Orphaned socket will see such state change via
783 * subflow_sched_work_if_closed() and that path will properly
784 * destroy the msk as needed.
785 */
786 ssk_state = inet_sk_state_load(ssk);
787 if (ssk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DEAD))
788 mptcp_set_state(sk, ssk_state);
789 WRITE_ONCE(sk->sk_err, -err);
790
791 /* This barrier is coupled with smp_rmb() in mptcp_poll() */
792 smp_wmb();
793 sk_error_report(sk);
794 return true;
795 }
796
__mptcp_error_report(struct sock * sk)797 void __mptcp_error_report(struct sock *sk)
798 {
799 struct mptcp_subflow_context *subflow;
800 struct mptcp_sock *msk = mptcp_sk(sk);
801
802 mptcp_for_each_subflow(msk, subflow)
803 if (__mptcp_subflow_error_report(sk, mptcp_subflow_tcp_sock(subflow)))
804 break;
805 }
806
807 /* In most cases we will be able to lock the mptcp socket. If its already
808 * owned, we need to defer to the work queue to avoid ABBA deadlock.
809 */
move_skbs_to_msk(struct mptcp_sock * msk,struct sock * ssk)810 static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk)
811 {
812 struct sock *sk = (struct sock *)msk;
813 bool moved;
814
815 moved = __mptcp_move_skbs_from_subflow(msk, ssk);
816 __mptcp_ofo_queue(msk);
817 if (unlikely(ssk->sk_err))
818 __mptcp_subflow_error_report(sk, ssk);
819
820 /* If the moves have caught up with the DATA_FIN sequence number
821 * it's time to ack the DATA_FIN and change socket state, but
822 * this is not a good place to change state. Let the workqueue
823 * do it.
824 */
825 if (mptcp_pending_data_fin(sk, NULL))
826 mptcp_schedule_work(sk);
827 return moved;
828 }
829
__mptcp_data_ready(struct sock * sk,struct sock * ssk)830 static void __mptcp_data_ready(struct sock *sk, struct sock *ssk)
831 {
832 struct mptcp_sock *msk = mptcp_sk(sk);
833
834 /* Wake-up the reader only for in-sequence data */
835 if (move_skbs_to_msk(msk, ssk) && mptcp_epollin_ready(sk))
836 sk->sk_data_ready(sk);
837 }
838
mptcp_data_ready(struct sock * sk,struct sock * ssk)839 void mptcp_data_ready(struct sock *sk, struct sock *ssk)
840 {
841 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
842
843 /* The peer can send data while we are shutting down this
844 * subflow at msk destruction time, but we must avoid enqueuing
845 * more data to the msk receive queue
846 */
847 if (unlikely(subflow->disposable))
848 return;
849
850 mptcp_data_lock(sk);
851 if (!sock_owned_by_user(sk))
852 __mptcp_data_ready(sk, ssk);
853 else
854 __set_bit(MPTCP_DEQUEUE, &mptcp_sk(sk)->cb_flags);
855 mptcp_data_unlock(sk);
856 }
857
mptcp_subflow_joined(struct mptcp_sock * msk,struct sock * ssk)858 static void mptcp_subflow_joined(struct mptcp_sock *msk, struct sock *ssk)
859 {
860 mptcp_subflow_ctx(ssk)->map_seq = READ_ONCE(msk->ack_seq);
861 msk->allow_infinite_fallback = false;
862 mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC);
863 }
864
__mptcp_finish_join(struct mptcp_sock * msk,struct sock * ssk)865 static bool __mptcp_finish_join(struct mptcp_sock *msk, struct sock *ssk)
866 {
867 struct sock *sk = (struct sock *)msk;
868
869 if (sk->sk_state != TCP_ESTABLISHED)
870 return false;
871
872 spin_lock_bh(&msk->fallback_lock);
873 if (!msk->allow_subflows) {
874 spin_unlock_bh(&msk->fallback_lock);
875 return false;
876 }
877 mptcp_subflow_joined(msk, ssk);
878 spin_unlock_bh(&msk->fallback_lock);
879
880 /* attach to msk socket only after we are sure we will deal with it
881 * at close time
882 */
883 if (sk->sk_socket && !ssk->sk_socket)
884 mptcp_sock_graft(ssk, sk->sk_socket);
885
886 mptcp_subflow_ctx(ssk)->subflow_id = msk->subflow_id++;
887 mptcp_sockopt_sync_locked(msk, ssk);
888 mptcp_stop_tout_timer(sk);
889 __mptcp_propagate_sndbuf(sk, ssk);
890 return true;
891 }
892
__mptcp_flush_join_list(struct sock * sk,struct list_head * join_list)893 static void __mptcp_flush_join_list(struct sock *sk, struct list_head *join_list)
894 {
895 struct mptcp_subflow_context *tmp, *subflow;
896 struct mptcp_sock *msk = mptcp_sk(sk);
897
898 list_for_each_entry_safe(subflow, tmp, join_list, node) {
899 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
900 bool slow = lock_sock_fast(ssk);
901
902 list_move_tail(&subflow->node, &msk->conn_list);
903 if (!__mptcp_finish_join(msk, ssk))
904 mptcp_subflow_reset(ssk);
905 unlock_sock_fast(ssk, slow);
906 }
907 }
908
mptcp_rtx_timer_pending(struct sock * sk)909 static bool mptcp_rtx_timer_pending(struct sock *sk)
910 {
911 return timer_pending(&inet_csk(sk)->icsk_retransmit_timer);
912 }
913
mptcp_reset_rtx_timer(struct sock * sk)914 static void mptcp_reset_rtx_timer(struct sock *sk)
915 {
916 struct inet_connection_sock *icsk = inet_csk(sk);
917 unsigned long tout;
918
919 /* prevent rescheduling on close */
920 if (unlikely(inet_sk_state_load(sk) == TCP_CLOSE))
921 return;
922
923 tout = mptcp_sk(sk)->timer_ival;
924 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout);
925 }
926
mptcp_schedule_work(struct sock * sk)927 bool mptcp_schedule_work(struct sock *sk)
928 {
929 if (inet_sk_state_load(sk) != TCP_CLOSE &&
930 schedule_work(&mptcp_sk(sk)->work)) {
931 /* each subflow already holds a reference to the sk, and the
932 * workqueue is invoked by a subflow, so sk can't go away here.
933 */
934 sock_hold(sk);
935 return true;
936 }
937 return false;
938 }
939
mptcp_skb_can_collapse_to(u64 write_seq,const struct sk_buff * skb,const struct mptcp_ext * mpext)940 static bool mptcp_skb_can_collapse_to(u64 write_seq,
941 const struct sk_buff *skb,
942 const struct mptcp_ext *mpext)
943 {
944 if (!tcp_skb_can_collapse_to(skb))
945 return false;
946
947 /* can collapse only if MPTCP level sequence is in order and this
948 * mapping has not been xmitted yet
949 */
950 return mpext && mpext->data_seq + mpext->data_len == write_seq &&
951 !mpext->frozen;
952 }
953
954 /* we can append data to the given data frag if:
955 * - there is space available in the backing page_frag
956 * - the data frag tail matches the current page_frag free offset
957 * - the data frag end sequence number matches the current write seq
958 */
mptcp_frag_can_collapse_to(const struct mptcp_sock * msk,const struct page_frag * pfrag,const struct mptcp_data_frag * df)959 static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk,
960 const struct page_frag *pfrag,
961 const struct mptcp_data_frag *df)
962 {
963 return df && pfrag->page == df->page &&
964 pfrag->size - pfrag->offset > 0 &&
965 pfrag->offset == (df->offset + df->data_len) &&
966 df->data_seq + df->data_len == msk->write_seq;
967 }
968
dfrag_uncharge(struct sock * sk,int len)969 static void dfrag_uncharge(struct sock *sk, int len)
970 {
971 sk_mem_uncharge(sk, len);
972 sk_wmem_queued_add(sk, -len);
973 }
974
dfrag_clear(struct sock * sk,struct mptcp_data_frag * dfrag)975 static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag)
976 {
977 int len = dfrag->data_len + dfrag->overhead;
978
979 list_del(&dfrag->list);
980 dfrag_uncharge(sk, len);
981 put_page(dfrag->page);
982 }
983
984 /* called under both the msk socket lock and the data lock */
__mptcp_clean_una(struct sock * sk)985 static void __mptcp_clean_una(struct sock *sk)
986 {
987 struct mptcp_sock *msk = mptcp_sk(sk);
988 struct mptcp_data_frag *dtmp, *dfrag;
989 u64 snd_una;
990
991 snd_una = msk->snd_una;
992 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) {
993 if (after64(dfrag->data_seq + dfrag->data_len, snd_una))
994 break;
995
996 if (unlikely(dfrag == msk->first_pending)) {
997 /* in recovery mode can see ack after the current snd head */
998 if (WARN_ON_ONCE(!msk->recovery))
999 break;
1000
1001 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1002 }
1003
1004 dfrag_clear(sk, dfrag);
1005 }
1006
1007 dfrag = mptcp_rtx_head(sk);
1008 if (dfrag && after64(snd_una, dfrag->data_seq)) {
1009 u64 delta = snd_una - dfrag->data_seq;
1010
1011 /* prevent wrap around in recovery mode */
1012 if (unlikely(delta > dfrag->already_sent)) {
1013 if (WARN_ON_ONCE(!msk->recovery))
1014 goto out;
1015 if (WARN_ON_ONCE(delta > dfrag->data_len))
1016 goto out;
1017 dfrag->already_sent += delta - dfrag->already_sent;
1018 }
1019
1020 dfrag->data_seq += delta;
1021 dfrag->offset += delta;
1022 dfrag->data_len -= delta;
1023 dfrag->already_sent -= delta;
1024
1025 dfrag_uncharge(sk, delta);
1026 }
1027
1028 /* all retransmitted data acked, recovery completed */
1029 if (unlikely(msk->recovery) && after64(msk->snd_una, msk->recovery_snd_nxt))
1030 msk->recovery = false;
1031
1032 out:
1033 if (snd_una == msk->snd_nxt && snd_una == msk->write_seq) {
1034 if (mptcp_rtx_timer_pending(sk) && !mptcp_data_fin_enabled(msk))
1035 mptcp_stop_rtx_timer(sk);
1036 } else {
1037 mptcp_reset_rtx_timer(sk);
1038 }
1039
1040 if (mptcp_pending_data_fin_ack(sk))
1041 mptcp_schedule_work(sk);
1042 }
1043
__mptcp_clean_una_wakeup(struct sock * sk)1044 static void __mptcp_clean_una_wakeup(struct sock *sk)
1045 {
1046 lockdep_assert_held_once(&sk->sk_lock.slock);
1047
1048 __mptcp_clean_una(sk);
1049 mptcp_write_space(sk);
1050 }
1051
mptcp_clean_una_wakeup(struct sock * sk)1052 static void mptcp_clean_una_wakeup(struct sock *sk)
1053 {
1054 mptcp_data_lock(sk);
1055 __mptcp_clean_una_wakeup(sk);
1056 mptcp_data_unlock(sk);
1057 }
1058
mptcp_enter_memory_pressure(struct sock * sk)1059 static void mptcp_enter_memory_pressure(struct sock *sk)
1060 {
1061 struct mptcp_subflow_context *subflow;
1062 struct mptcp_sock *msk = mptcp_sk(sk);
1063 bool first = true;
1064
1065 mptcp_for_each_subflow(msk, subflow) {
1066 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
1067
1068 if (first)
1069 tcp_enter_memory_pressure(ssk);
1070 sk_stream_moderate_sndbuf(ssk);
1071
1072 first = false;
1073 }
1074 __mptcp_sync_sndbuf(sk);
1075 }
1076
1077 /* ensure we get enough memory for the frag hdr, beyond some minimal amount of
1078 * data
1079 */
mptcp_page_frag_refill(struct sock * sk,struct page_frag * pfrag)1080 static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag)
1081 {
1082 if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag),
1083 pfrag, sk->sk_allocation)))
1084 return true;
1085
1086 mptcp_enter_memory_pressure(sk);
1087 return false;
1088 }
1089
1090 static struct mptcp_data_frag *
mptcp_carve_data_frag(const struct mptcp_sock * msk,struct page_frag * pfrag,int orig_offset)1091 mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag,
1092 int orig_offset)
1093 {
1094 int offset = ALIGN(orig_offset, sizeof(long));
1095 struct mptcp_data_frag *dfrag;
1096
1097 dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset);
1098 dfrag->data_len = 0;
1099 dfrag->data_seq = msk->write_seq;
1100 dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag);
1101 dfrag->offset = offset + sizeof(struct mptcp_data_frag);
1102 dfrag->already_sent = 0;
1103 dfrag->page = pfrag->page;
1104
1105 return dfrag;
1106 }
1107
1108 struct mptcp_sendmsg_info {
1109 int mss_now;
1110 int size_goal;
1111 u16 limit;
1112 u16 sent;
1113 unsigned int flags;
1114 bool data_lock_held;
1115 };
1116
mptcp_check_allowed_size(const struct mptcp_sock * msk,struct sock * ssk,u64 data_seq,int avail_size)1117 static int mptcp_check_allowed_size(const struct mptcp_sock *msk, struct sock *ssk,
1118 u64 data_seq, int avail_size)
1119 {
1120 u64 window_end = mptcp_wnd_end(msk);
1121 u64 mptcp_snd_wnd;
1122
1123 if (__mptcp_check_fallback(msk))
1124 return avail_size;
1125
1126 mptcp_snd_wnd = window_end - data_seq;
1127 avail_size = min_t(unsigned int, mptcp_snd_wnd, avail_size);
1128
1129 if (unlikely(tcp_sk(ssk)->snd_wnd < mptcp_snd_wnd)) {
1130 tcp_sk(ssk)->snd_wnd = min_t(u64, U32_MAX, mptcp_snd_wnd);
1131 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_SNDWNDSHARED);
1132 }
1133
1134 return avail_size;
1135 }
1136
__mptcp_add_ext(struct sk_buff * skb,gfp_t gfp)1137 static bool __mptcp_add_ext(struct sk_buff *skb, gfp_t gfp)
1138 {
1139 struct skb_ext *mpext = __skb_ext_alloc(gfp);
1140
1141 if (!mpext)
1142 return false;
1143 __skb_ext_set(skb, SKB_EXT_MPTCP, mpext);
1144 return true;
1145 }
1146
__mptcp_do_alloc_tx_skb(struct sock * sk,gfp_t gfp)1147 static struct sk_buff *__mptcp_do_alloc_tx_skb(struct sock *sk, gfp_t gfp)
1148 {
1149 struct sk_buff *skb;
1150
1151 skb = alloc_skb_fclone(MAX_TCP_HEADER, gfp);
1152 if (likely(skb)) {
1153 if (likely(__mptcp_add_ext(skb, gfp))) {
1154 skb_reserve(skb, MAX_TCP_HEADER);
1155 skb->ip_summed = CHECKSUM_PARTIAL;
1156 INIT_LIST_HEAD(&skb->tcp_tsorted_anchor);
1157 return skb;
1158 }
1159 __kfree_skb(skb);
1160 } else {
1161 mptcp_enter_memory_pressure(sk);
1162 }
1163 return NULL;
1164 }
1165
__mptcp_alloc_tx_skb(struct sock * sk,struct sock * ssk,gfp_t gfp)1166 static struct sk_buff *__mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, gfp_t gfp)
1167 {
1168 struct sk_buff *skb;
1169
1170 skb = __mptcp_do_alloc_tx_skb(sk, gfp);
1171 if (!skb)
1172 return NULL;
1173
1174 if (likely(sk_wmem_schedule(ssk, skb->truesize))) {
1175 tcp_skb_entail(ssk, skb);
1176 return skb;
1177 }
1178 tcp_skb_tsorted_anchor_cleanup(skb);
1179 kfree_skb(skb);
1180 return NULL;
1181 }
1182
mptcp_alloc_tx_skb(struct sock * sk,struct sock * ssk,bool data_lock_held)1183 static struct sk_buff *mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, bool data_lock_held)
1184 {
1185 gfp_t gfp = data_lock_held ? GFP_ATOMIC : sk->sk_allocation;
1186
1187 return __mptcp_alloc_tx_skb(sk, ssk, gfp);
1188 }
1189
1190 /* note: this always recompute the csum on the whole skb, even
1191 * if we just appended a single frag. More status info needed
1192 */
mptcp_update_data_checksum(struct sk_buff * skb,int added)1193 static void mptcp_update_data_checksum(struct sk_buff *skb, int added)
1194 {
1195 struct mptcp_ext *mpext = mptcp_get_ext(skb);
1196 __wsum csum = ~csum_unfold(mpext->csum);
1197 int offset = skb->len - added;
1198
1199 mpext->csum = csum_fold(csum_block_add(csum, skb_checksum(skb, offset, added, 0), offset));
1200 }
1201
mptcp_update_infinite_map(struct mptcp_sock * msk,struct sock * ssk,struct mptcp_ext * mpext)1202 static void mptcp_update_infinite_map(struct mptcp_sock *msk,
1203 struct sock *ssk,
1204 struct mptcp_ext *mpext)
1205 {
1206 if (!mpext)
1207 return;
1208
1209 mpext->infinite_map = 1;
1210 mpext->data_len = 0;
1211
1212 if (!mptcp_try_fallback(ssk, MPTCP_MIB_INFINITEMAPTX)) {
1213 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_FALLBACKFAILED);
1214 mptcp_subflow_reset(ssk);
1215 return;
1216 }
1217
1218 mptcp_subflow_ctx(ssk)->send_infinite_map = 0;
1219 }
1220
1221 #define MPTCP_MAX_GSO_SIZE (GSO_LEGACY_MAX_SIZE - (MAX_TCP_HEADER + 1))
1222
mptcp_sendmsg_frag(struct sock * sk,struct sock * ssk,struct mptcp_data_frag * dfrag,struct mptcp_sendmsg_info * info)1223 static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
1224 struct mptcp_data_frag *dfrag,
1225 struct mptcp_sendmsg_info *info)
1226 {
1227 u64 data_seq = dfrag->data_seq + info->sent;
1228 int offset = dfrag->offset + info->sent;
1229 struct mptcp_sock *msk = mptcp_sk(sk);
1230 bool zero_window_probe = false;
1231 struct mptcp_ext *mpext = NULL;
1232 bool can_coalesce = false;
1233 bool reuse_skb = true;
1234 struct sk_buff *skb;
1235 size_t copy;
1236 int i;
1237
1238 pr_debug("msk=%p ssk=%p sending dfrag at seq=%llu len=%u already sent=%u\n",
1239 msk, ssk, dfrag->data_seq, dfrag->data_len, info->sent);
1240
1241 if (WARN_ON_ONCE(info->sent > info->limit ||
1242 info->limit > dfrag->data_len))
1243 return 0;
1244
1245 if (unlikely(!__tcp_can_send(ssk)))
1246 return -EAGAIN;
1247
1248 /* compute send limit */
1249 if (unlikely(ssk->sk_gso_max_size > MPTCP_MAX_GSO_SIZE))
1250 ssk->sk_gso_max_size = MPTCP_MAX_GSO_SIZE;
1251 info->mss_now = tcp_send_mss(ssk, &info->size_goal, info->flags);
1252 copy = info->size_goal;
1253
1254 skb = tcp_write_queue_tail(ssk);
1255 if (skb && copy > skb->len) {
1256 /* Limit the write to the size available in the
1257 * current skb, if any, so that we create at most a new skb.
1258 * Explicitly tells TCP internals to avoid collapsing on later
1259 * queue management operation, to avoid breaking the ext <->
1260 * SSN association set here
1261 */
1262 mpext = mptcp_get_ext(skb);
1263 if (!mptcp_skb_can_collapse_to(data_seq, skb, mpext)) {
1264 TCP_SKB_CB(skb)->eor = 1;
1265 tcp_mark_push(tcp_sk(ssk), skb);
1266 goto alloc_skb;
1267 }
1268
1269 i = skb_shinfo(skb)->nr_frags;
1270 can_coalesce = skb_can_coalesce(skb, i, dfrag->page, offset);
1271 if (!can_coalesce && i >= READ_ONCE(net_hotdata.sysctl_max_skb_frags)) {
1272 tcp_mark_push(tcp_sk(ssk), skb);
1273 goto alloc_skb;
1274 }
1275
1276 copy -= skb->len;
1277 } else {
1278 alloc_skb:
1279 skb = mptcp_alloc_tx_skb(sk, ssk, info->data_lock_held);
1280 if (!skb)
1281 return -ENOMEM;
1282
1283 i = skb_shinfo(skb)->nr_frags;
1284 reuse_skb = false;
1285 mpext = mptcp_get_ext(skb);
1286 }
1287
1288 /* Zero window and all data acked? Probe. */
1289 copy = mptcp_check_allowed_size(msk, ssk, data_seq, copy);
1290 if (copy == 0) {
1291 u64 snd_una = READ_ONCE(msk->snd_una);
1292
1293 if (snd_una != msk->snd_nxt || tcp_write_queue_tail(ssk)) {
1294 tcp_remove_empty_skb(ssk);
1295 return 0;
1296 }
1297
1298 zero_window_probe = true;
1299 data_seq = snd_una - 1;
1300 copy = 1;
1301 }
1302
1303 copy = min_t(size_t, copy, info->limit - info->sent);
1304 if (!sk_wmem_schedule(ssk, copy)) {
1305 tcp_remove_empty_skb(ssk);
1306 return -ENOMEM;
1307 }
1308
1309 if (can_coalesce) {
1310 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1311 } else {
1312 get_page(dfrag->page);
1313 skb_fill_page_desc(skb, i, dfrag->page, offset, copy);
1314 }
1315
1316 skb->len += copy;
1317 skb->data_len += copy;
1318 skb->truesize += copy;
1319 sk_wmem_queued_add(ssk, copy);
1320 sk_mem_charge(ssk, copy);
1321 WRITE_ONCE(tcp_sk(ssk)->write_seq, tcp_sk(ssk)->write_seq + copy);
1322 TCP_SKB_CB(skb)->end_seq += copy;
1323 tcp_skb_pcount_set(skb, 0);
1324
1325 /* on skb reuse we just need to update the DSS len */
1326 if (reuse_skb) {
1327 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1328 mpext->data_len += copy;
1329 goto out;
1330 }
1331
1332 memset(mpext, 0, sizeof(*mpext));
1333 mpext->data_seq = data_seq;
1334 mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq;
1335 mpext->data_len = copy;
1336 mpext->use_map = 1;
1337 mpext->dsn64 = 1;
1338
1339 pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d\n",
1340 mpext->data_seq, mpext->subflow_seq, mpext->data_len,
1341 mpext->dsn64);
1342
1343 if (zero_window_probe) {
1344 mptcp_subflow_ctx(ssk)->rel_write_seq += copy;
1345 mpext->frozen = 1;
1346 if (READ_ONCE(msk->csum_enabled))
1347 mptcp_update_data_checksum(skb, copy);
1348 tcp_push_pending_frames(ssk);
1349 return 0;
1350 }
1351 out:
1352 if (READ_ONCE(msk->csum_enabled))
1353 mptcp_update_data_checksum(skb, copy);
1354 if (mptcp_subflow_ctx(ssk)->send_infinite_map)
1355 mptcp_update_infinite_map(msk, ssk, mpext);
1356 trace_mptcp_sendmsg_frag(mpext);
1357 mptcp_subflow_ctx(ssk)->rel_write_seq += copy;
1358 return copy;
1359 }
1360
1361 #define MPTCP_SEND_BURST_SIZE ((1 << 16) - \
1362 sizeof(struct tcphdr) - \
1363 MAX_TCP_OPTION_SPACE - \
1364 sizeof(struct ipv6hdr) - \
1365 sizeof(struct frag_hdr))
1366
1367 struct subflow_send_info {
1368 struct sock *ssk;
1369 u64 linger_time;
1370 };
1371
mptcp_subflow_set_active(struct mptcp_subflow_context * subflow)1372 void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow)
1373 {
1374 if (!subflow->stale)
1375 return;
1376
1377 subflow->stale = 0;
1378 MPTCP_INC_STATS(sock_net(mptcp_subflow_tcp_sock(subflow)), MPTCP_MIB_SUBFLOWRECOVER);
1379 }
1380
mptcp_subflow_active(struct mptcp_subflow_context * subflow)1381 bool mptcp_subflow_active(struct mptcp_subflow_context *subflow)
1382 {
1383 if (unlikely(subflow->stale)) {
1384 u32 rcv_tstamp = READ_ONCE(tcp_sk(mptcp_subflow_tcp_sock(subflow))->rcv_tstamp);
1385
1386 if (subflow->stale_rcv_tstamp == rcv_tstamp)
1387 return false;
1388
1389 mptcp_subflow_set_active(subflow);
1390 }
1391 return __mptcp_subflow_active(subflow);
1392 }
1393
1394 #define SSK_MODE_ACTIVE 0
1395 #define SSK_MODE_BACKUP 1
1396 #define SSK_MODE_MAX 2
1397
1398 /* implement the mptcp packet scheduler;
1399 * returns the subflow that will transmit the next DSS
1400 * additionally updates the rtx timeout
1401 */
mptcp_subflow_get_send(struct mptcp_sock * msk)1402 struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk)
1403 {
1404 struct subflow_send_info send_info[SSK_MODE_MAX];
1405 struct mptcp_subflow_context *subflow;
1406 struct sock *sk = (struct sock *)msk;
1407 u32 pace, burst, wmem;
1408 int i, nr_active = 0;
1409 struct sock *ssk;
1410 u64 linger_time;
1411 long tout = 0;
1412
1413 /* pick the subflow with the lower wmem/wspace ratio */
1414 for (i = 0; i < SSK_MODE_MAX; ++i) {
1415 send_info[i].ssk = NULL;
1416 send_info[i].linger_time = -1;
1417 }
1418
1419 mptcp_for_each_subflow(msk, subflow) {
1420 bool backup = subflow->backup || subflow->request_bkup;
1421
1422 trace_mptcp_subflow_get_send(subflow);
1423 ssk = mptcp_subflow_tcp_sock(subflow);
1424 if (!mptcp_subflow_active(subflow))
1425 continue;
1426
1427 tout = max(tout, mptcp_timeout_from_subflow(subflow));
1428 nr_active += !backup;
1429 pace = subflow->avg_pacing_rate;
1430 if (unlikely(!pace)) {
1431 /* init pacing rate from socket */
1432 subflow->avg_pacing_rate = READ_ONCE(ssk->sk_pacing_rate);
1433 pace = subflow->avg_pacing_rate;
1434 if (!pace)
1435 continue;
1436 }
1437
1438 linger_time = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32, pace);
1439 if (linger_time < send_info[backup].linger_time) {
1440 send_info[backup].ssk = ssk;
1441 send_info[backup].linger_time = linger_time;
1442 }
1443 }
1444 __mptcp_set_timeout(sk, tout);
1445
1446 /* pick the best backup if no other subflow is active */
1447 if (!nr_active)
1448 send_info[SSK_MODE_ACTIVE].ssk = send_info[SSK_MODE_BACKUP].ssk;
1449
1450 /* According to the blest algorithm, to avoid HoL blocking for the
1451 * faster flow, we need to:
1452 * - estimate the faster flow linger time
1453 * - use the above to estimate the amount of byte transferred
1454 * by the faster flow
1455 * - check that the amount of queued data is greater than the above,
1456 * otherwise do not use the picked, slower, subflow
1457 * We select the subflow with the shorter estimated time to flush
1458 * the queued mem, which basically ensure the above. We just need
1459 * to check that subflow has a non empty cwin.
1460 */
1461 ssk = send_info[SSK_MODE_ACTIVE].ssk;
1462 if (!ssk || !sk_stream_memory_free(ssk))
1463 return NULL;
1464
1465 burst = min_t(int, MPTCP_SEND_BURST_SIZE, mptcp_wnd_end(msk) - msk->snd_nxt);
1466 wmem = READ_ONCE(ssk->sk_wmem_queued);
1467 if (!burst)
1468 return ssk;
1469
1470 subflow = mptcp_subflow_ctx(ssk);
1471 subflow->avg_pacing_rate = div_u64((u64)subflow->avg_pacing_rate * wmem +
1472 READ_ONCE(ssk->sk_pacing_rate) * burst,
1473 burst + wmem);
1474 msk->snd_burst = burst;
1475 return ssk;
1476 }
1477
mptcp_push_release(struct sock * ssk,struct mptcp_sendmsg_info * info)1478 static void mptcp_push_release(struct sock *ssk, struct mptcp_sendmsg_info *info)
1479 {
1480 tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal);
1481 release_sock(ssk);
1482 }
1483
mptcp_update_post_push(struct mptcp_sock * msk,struct mptcp_data_frag * dfrag,u32 sent)1484 static void mptcp_update_post_push(struct mptcp_sock *msk,
1485 struct mptcp_data_frag *dfrag,
1486 u32 sent)
1487 {
1488 u64 snd_nxt_new = dfrag->data_seq;
1489
1490 dfrag->already_sent += sent;
1491
1492 msk->snd_burst -= sent;
1493
1494 snd_nxt_new += dfrag->already_sent;
1495
1496 /* snd_nxt_new can be smaller than snd_nxt in case mptcp
1497 * is recovering after a failover. In that event, this re-sends
1498 * old segments.
1499 *
1500 * Thus compute snd_nxt_new candidate based on
1501 * the dfrag->data_seq that was sent and the data
1502 * that has been handed to the subflow for transmission
1503 * and skip update in case it was old dfrag.
1504 */
1505 if (likely(after64(snd_nxt_new, msk->snd_nxt))) {
1506 msk->bytes_sent += snd_nxt_new - msk->snd_nxt;
1507 WRITE_ONCE(msk->snd_nxt, snd_nxt_new);
1508 }
1509 }
1510
mptcp_check_and_set_pending(struct sock * sk)1511 void mptcp_check_and_set_pending(struct sock *sk)
1512 {
1513 if (mptcp_send_head(sk)) {
1514 mptcp_data_lock(sk);
1515 mptcp_sk(sk)->cb_flags |= BIT(MPTCP_PUSH_PENDING);
1516 mptcp_data_unlock(sk);
1517 }
1518 }
1519
__subflow_push_pending(struct sock * sk,struct sock * ssk,struct mptcp_sendmsg_info * info)1520 static int __subflow_push_pending(struct sock *sk, struct sock *ssk,
1521 struct mptcp_sendmsg_info *info)
1522 {
1523 struct mptcp_sock *msk = mptcp_sk(sk);
1524 struct mptcp_data_frag *dfrag;
1525 int len, copied = 0, err = 0;
1526
1527 while ((dfrag = mptcp_send_head(sk))) {
1528 info->sent = dfrag->already_sent;
1529 info->limit = dfrag->data_len;
1530 len = dfrag->data_len - dfrag->already_sent;
1531 while (len > 0) {
1532 int ret = 0;
1533
1534 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, info);
1535 if (ret <= 0) {
1536 err = copied ? : ret;
1537 goto out;
1538 }
1539
1540 info->sent += ret;
1541 copied += ret;
1542 len -= ret;
1543
1544 mptcp_update_post_push(msk, dfrag, ret);
1545 }
1546 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1547
1548 if (msk->snd_burst <= 0 ||
1549 !sk_stream_memory_free(ssk) ||
1550 !mptcp_subflow_active(mptcp_subflow_ctx(ssk))) {
1551 err = copied;
1552 goto out;
1553 }
1554 mptcp_set_timeout(sk);
1555 }
1556 err = copied;
1557
1558 out:
1559 if (err > 0)
1560 msk->last_data_sent = tcp_jiffies32;
1561 return err;
1562 }
1563
__mptcp_push_pending(struct sock * sk,unsigned int flags)1564 void __mptcp_push_pending(struct sock *sk, unsigned int flags)
1565 {
1566 struct sock *prev_ssk = NULL, *ssk = NULL;
1567 struct mptcp_sock *msk = mptcp_sk(sk);
1568 struct mptcp_sendmsg_info info = {
1569 .flags = flags,
1570 };
1571 bool do_check_data_fin = false;
1572 int push_count = 1;
1573
1574 while (mptcp_send_head(sk) && (push_count > 0)) {
1575 struct mptcp_subflow_context *subflow;
1576 int ret = 0;
1577
1578 if (mptcp_sched_get_send(msk))
1579 break;
1580
1581 push_count = 0;
1582
1583 mptcp_for_each_subflow(msk, subflow) {
1584 if (READ_ONCE(subflow->scheduled)) {
1585 mptcp_subflow_set_scheduled(subflow, false);
1586
1587 prev_ssk = ssk;
1588 ssk = mptcp_subflow_tcp_sock(subflow);
1589 if (ssk != prev_ssk) {
1590 /* First check. If the ssk has changed since
1591 * the last round, release prev_ssk
1592 */
1593 if (prev_ssk)
1594 mptcp_push_release(prev_ssk, &info);
1595
1596 /* Need to lock the new subflow only if different
1597 * from the previous one, otherwise we are still
1598 * helding the relevant lock
1599 */
1600 lock_sock(ssk);
1601 }
1602
1603 push_count++;
1604
1605 ret = __subflow_push_pending(sk, ssk, &info);
1606 if (ret <= 0) {
1607 if (ret != -EAGAIN ||
1608 (1 << ssk->sk_state) &
1609 (TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSE))
1610 push_count--;
1611 continue;
1612 }
1613 do_check_data_fin = true;
1614 }
1615 }
1616 }
1617
1618 /* at this point we held the socket lock for the last subflow we used */
1619 if (ssk)
1620 mptcp_push_release(ssk, &info);
1621
1622 /* ensure the rtx timer is running */
1623 if (!mptcp_rtx_timer_pending(sk))
1624 mptcp_reset_rtx_timer(sk);
1625 if (do_check_data_fin)
1626 mptcp_check_send_data_fin(sk);
1627 }
1628
__mptcp_subflow_push_pending(struct sock * sk,struct sock * ssk,bool first)1629 static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk, bool first)
1630 {
1631 struct mptcp_sock *msk = mptcp_sk(sk);
1632 struct mptcp_sendmsg_info info = {
1633 .data_lock_held = true,
1634 };
1635 bool keep_pushing = true;
1636 struct sock *xmit_ssk;
1637 int copied = 0;
1638
1639 info.flags = 0;
1640 while (mptcp_send_head(sk) && keep_pushing) {
1641 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1642 int ret = 0;
1643
1644 /* check for a different subflow usage only after
1645 * spooling the first chunk of data
1646 */
1647 if (first) {
1648 mptcp_subflow_set_scheduled(subflow, false);
1649 ret = __subflow_push_pending(sk, ssk, &info);
1650 first = false;
1651 if (ret <= 0)
1652 break;
1653 copied += ret;
1654 continue;
1655 }
1656
1657 if (mptcp_sched_get_send(msk))
1658 goto out;
1659
1660 if (READ_ONCE(subflow->scheduled)) {
1661 mptcp_subflow_set_scheduled(subflow, false);
1662 ret = __subflow_push_pending(sk, ssk, &info);
1663 if (ret <= 0)
1664 keep_pushing = false;
1665 copied += ret;
1666 }
1667
1668 mptcp_for_each_subflow(msk, subflow) {
1669 if (READ_ONCE(subflow->scheduled)) {
1670 xmit_ssk = mptcp_subflow_tcp_sock(subflow);
1671 if (xmit_ssk != ssk) {
1672 mptcp_subflow_delegate(subflow,
1673 MPTCP_DELEGATE_SEND);
1674 keep_pushing = false;
1675 }
1676 }
1677 }
1678 }
1679
1680 out:
1681 /* __mptcp_alloc_tx_skb could have released some wmem and we are
1682 * not going to flush it via release_sock()
1683 */
1684 if (copied) {
1685 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
1686 info.size_goal);
1687 if (!mptcp_rtx_timer_pending(sk))
1688 mptcp_reset_rtx_timer(sk);
1689
1690 if (msk->snd_data_fin_enable &&
1691 msk->snd_nxt + 1 == msk->write_seq)
1692 mptcp_schedule_work(sk);
1693 }
1694 }
1695
1696 static int mptcp_disconnect(struct sock *sk, int flags);
1697
mptcp_sendmsg_fastopen(struct sock * sk,struct msghdr * msg,size_t len,int * copied_syn)1698 static int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
1699 size_t len, int *copied_syn)
1700 {
1701 unsigned int saved_flags = msg->msg_flags;
1702 struct mptcp_sock *msk = mptcp_sk(sk);
1703 struct sock *ssk;
1704 int ret;
1705
1706 /* on flags based fastopen the mptcp is supposed to create the
1707 * first subflow right now. Otherwise we are in the defer_connect
1708 * path, and the first subflow must be already present.
1709 * Since the defer_connect flag is cleared after the first succsful
1710 * fastopen attempt, no need to check for additional subflow status.
1711 */
1712 if (msg->msg_flags & MSG_FASTOPEN) {
1713 ssk = __mptcp_nmpc_sk(msk);
1714 if (IS_ERR(ssk))
1715 return PTR_ERR(ssk);
1716 }
1717 if (!msk->first)
1718 return -EINVAL;
1719
1720 ssk = msk->first;
1721
1722 lock_sock(ssk);
1723 msg->msg_flags |= MSG_DONTWAIT;
1724 msk->fastopening = 1;
1725 ret = tcp_sendmsg_fastopen(ssk, msg, copied_syn, len, NULL);
1726 msk->fastopening = 0;
1727 msg->msg_flags = saved_flags;
1728 release_sock(ssk);
1729
1730 /* do the blocking bits of inet_stream_connect outside the ssk socket lock */
1731 if (ret == -EINPROGRESS && !(msg->msg_flags & MSG_DONTWAIT)) {
1732 ret = __inet_stream_connect(sk->sk_socket, msg->msg_name,
1733 msg->msg_namelen, msg->msg_flags, 1);
1734
1735 /* Keep the same behaviour of plain TCP: zero the copied bytes in
1736 * case of any error, except timeout or signal
1737 */
1738 if (ret && ret != -EINPROGRESS && ret != -ERESTARTSYS && ret != -EINTR)
1739 *copied_syn = 0;
1740 } else if (ret && ret != -EINPROGRESS) {
1741 /* The disconnect() op called by tcp_sendmsg_fastopen()/
1742 * __inet_stream_connect() can fail, due to looking check,
1743 * see mptcp_disconnect().
1744 * Attempt it again outside the problematic scope.
1745 */
1746 if (!mptcp_disconnect(sk, 0)) {
1747 sk->sk_disconnects++;
1748 sk->sk_socket->state = SS_UNCONNECTED;
1749 }
1750 }
1751 inet_clear_bit(DEFER_CONNECT, sk);
1752
1753 return ret;
1754 }
1755
do_copy_data_nocache(struct sock * sk,int copy,struct iov_iter * from,char * to)1756 static int do_copy_data_nocache(struct sock *sk, int copy,
1757 struct iov_iter *from, char *to)
1758 {
1759 if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) {
1760 if (!copy_from_iter_full_nocache(to, copy, from))
1761 return -EFAULT;
1762 } else if (!copy_from_iter_full(to, copy, from)) {
1763 return -EFAULT;
1764 }
1765 return 0;
1766 }
1767
1768 /* open-code sk_stream_memory_free() plus sent limit computation to
1769 * avoid indirect calls in fast-path.
1770 * Called under the msk socket lock, so we can avoid a bunch of ONCE
1771 * annotations.
1772 */
mptcp_send_limit(const struct sock * sk)1773 static u32 mptcp_send_limit(const struct sock *sk)
1774 {
1775 const struct mptcp_sock *msk = mptcp_sk(sk);
1776 u32 limit, not_sent;
1777
1778 if (sk->sk_wmem_queued >= READ_ONCE(sk->sk_sndbuf))
1779 return 0;
1780
1781 limit = mptcp_notsent_lowat(sk);
1782 if (limit == UINT_MAX)
1783 return UINT_MAX;
1784
1785 not_sent = msk->write_seq - msk->snd_nxt;
1786 if (not_sent >= limit)
1787 return 0;
1788
1789 return limit - not_sent;
1790 }
1791
mptcp_rps_record_subflows(const struct mptcp_sock * msk)1792 static void mptcp_rps_record_subflows(const struct mptcp_sock *msk)
1793 {
1794 struct mptcp_subflow_context *subflow;
1795
1796 if (!rfs_is_needed())
1797 return;
1798
1799 mptcp_for_each_subflow(msk, subflow) {
1800 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
1801
1802 sock_rps_record_flow(ssk);
1803 }
1804 }
1805
mptcp_sendmsg(struct sock * sk,struct msghdr * msg,size_t len)1806 static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
1807 {
1808 struct mptcp_sock *msk = mptcp_sk(sk);
1809 struct page_frag *pfrag;
1810 size_t copied = 0;
1811 int ret = 0;
1812 long timeo;
1813
1814 /* silently ignore everything else */
1815 msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | MSG_FASTOPEN;
1816
1817 lock_sock(sk);
1818
1819 mptcp_rps_record_subflows(msk);
1820
1821 if (unlikely(inet_test_bit(DEFER_CONNECT, sk) ||
1822 msg->msg_flags & MSG_FASTOPEN)) {
1823 int copied_syn = 0;
1824
1825 ret = mptcp_sendmsg_fastopen(sk, msg, len, &copied_syn);
1826 copied += copied_syn;
1827 if (ret == -EINPROGRESS && copied_syn > 0)
1828 goto out;
1829 else if (ret)
1830 goto do_error;
1831 }
1832
1833 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1834
1835 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
1836 ret = sk_stream_wait_connect(sk, &timeo);
1837 if (ret)
1838 goto do_error;
1839 }
1840
1841 ret = -EPIPE;
1842 if (unlikely(sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)))
1843 goto do_error;
1844
1845 pfrag = sk_page_frag(sk);
1846
1847 while (msg_data_left(msg)) {
1848 int total_ts, frag_truesize = 0;
1849 struct mptcp_data_frag *dfrag;
1850 bool dfrag_collapsed;
1851 size_t psize, offset;
1852 u32 copy_limit;
1853
1854 /* ensure fitting the notsent_lowat() constraint */
1855 copy_limit = mptcp_send_limit(sk);
1856 if (!copy_limit)
1857 goto wait_for_memory;
1858
1859 /* reuse tail pfrag, if possible, or carve a new one from the
1860 * page allocator
1861 */
1862 dfrag = mptcp_pending_tail(sk);
1863 dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag);
1864 if (!dfrag_collapsed) {
1865 if (!mptcp_page_frag_refill(sk, pfrag))
1866 goto wait_for_memory;
1867
1868 dfrag = mptcp_carve_data_frag(msk, pfrag, pfrag->offset);
1869 frag_truesize = dfrag->overhead;
1870 }
1871
1872 /* we do not bound vs wspace, to allow a single packet.
1873 * memory accounting will prevent execessive memory usage
1874 * anyway
1875 */
1876 offset = dfrag->offset + dfrag->data_len;
1877 psize = pfrag->size - offset;
1878 psize = min_t(size_t, psize, msg_data_left(msg));
1879 psize = min_t(size_t, psize, copy_limit);
1880 total_ts = psize + frag_truesize;
1881
1882 if (!sk_wmem_schedule(sk, total_ts))
1883 goto wait_for_memory;
1884
1885 ret = do_copy_data_nocache(sk, psize, &msg->msg_iter,
1886 page_address(dfrag->page) + offset);
1887 if (ret)
1888 goto do_error;
1889
1890 /* data successfully copied into the write queue */
1891 sk_forward_alloc_add(sk, -total_ts);
1892 copied += psize;
1893 dfrag->data_len += psize;
1894 frag_truesize += psize;
1895 pfrag->offset += frag_truesize;
1896 WRITE_ONCE(msk->write_seq, msk->write_seq + psize);
1897
1898 /* charge data on mptcp pending queue to the msk socket
1899 * Note: we charge such data both to sk and ssk
1900 */
1901 sk_wmem_queued_add(sk, frag_truesize);
1902 if (!dfrag_collapsed) {
1903 get_page(dfrag->page);
1904 list_add_tail(&dfrag->list, &msk->rtx_queue);
1905 if (!msk->first_pending)
1906 WRITE_ONCE(msk->first_pending, dfrag);
1907 }
1908 pr_debug("msk=%p dfrag at seq=%llu len=%u sent=%u new=%d\n", msk,
1909 dfrag->data_seq, dfrag->data_len, dfrag->already_sent,
1910 !dfrag_collapsed);
1911
1912 continue;
1913
1914 wait_for_memory:
1915 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1916 __mptcp_push_pending(sk, msg->msg_flags);
1917 ret = sk_stream_wait_memory(sk, &timeo);
1918 if (ret)
1919 goto do_error;
1920 }
1921
1922 if (copied)
1923 __mptcp_push_pending(sk, msg->msg_flags);
1924
1925 out:
1926 release_sock(sk);
1927 return copied;
1928
1929 do_error:
1930 if (copied)
1931 goto out;
1932
1933 copied = sk_stream_error(sk, msg->msg_flags, ret);
1934 goto out;
1935 }
1936
1937 static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied);
1938
__mptcp_recvmsg_mskq(struct sock * sk,struct msghdr * msg,size_t len,int flags,struct scm_timestamping_internal * tss,int * cmsg_flags)1939 static int __mptcp_recvmsg_mskq(struct sock *sk,
1940 struct msghdr *msg,
1941 size_t len, int flags,
1942 struct scm_timestamping_internal *tss,
1943 int *cmsg_flags)
1944 {
1945 struct mptcp_sock *msk = mptcp_sk(sk);
1946 struct sk_buff *skb, *tmp;
1947 int copied = 0;
1948
1949 skb_queue_walk_safe(&sk->sk_receive_queue, skb, tmp) {
1950 u32 offset = MPTCP_SKB_CB(skb)->offset;
1951 u32 data_len = skb->len - offset;
1952 u32 count = min_t(size_t, len - copied, data_len);
1953 int err;
1954
1955 if (!(flags & MSG_TRUNC)) {
1956 err = skb_copy_datagram_msg(skb, offset, msg, count);
1957 if (unlikely(err < 0)) {
1958 if (!copied)
1959 return err;
1960 break;
1961 }
1962 }
1963
1964 if (MPTCP_SKB_CB(skb)->has_rxtstamp) {
1965 tcp_update_recv_tstamps(skb, tss);
1966 *cmsg_flags |= MPTCP_CMSG_TS;
1967 }
1968
1969 copied += count;
1970
1971 if (count < data_len) {
1972 if (!(flags & MSG_PEEK)) {
1973 MPTCP_SKB_CB(skb)->offset += count;
1974 MPTCP_SKB_CB(skb)->map_seq += count;
1975 msk->bytes_consumed += count;
1976 }
1977 break;
1978 }
1979
1980 if (!(flags & MSG_PEEK)) {
1981 /* avoid the indirect call, we know the destructor is sock_rfree */
1982 skb->destructor = NULL;
1983 skb->sk = NULL;
1984 atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
1985 sk_mem_uncharge(sk, skb->truesize);
1986 __skb_unlink(skb, &sk->sk_receive_queue);
1987 skb_attempt_defer_free(skb);
1988 msk->bytes_consumed += count;
1989 }
1990
1991 if (copied >= len)
1992 break;
1993 }
1994
1995 mptcp_rcv_space_adjust(msk, copied);
1996 return copied;
1997 }
1998
1999 /* receive buffer autotuning. See tcp_rcv_space_adjust for more information.
2000 *
2001 * Only difference: Use highest rtt estimate of the subflows in use.
2002 */
mptcp_rcv_space_adjust(struct mptcp_sock * msk,int copied)2003 static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied)
2004 {
2005 struct mptcp_subflow_context *subflow;
2006 struct sock *sk = (struct sock *)msk;
2007 u8 scaling_ratio = U8_MAX;
2008 u32 time, advmss = 1;
2009 u64 rtt_us, mstamp;
2010
2011 msk_owned_by_me(msk);
2012
2013 if (copied <= 0)
2014 return;
2015
2016 if (!msk->rcvspace_init)
2017 mptcp_rcv_space_init(msk, msk->first);
2018
2019 msk->rcvq_space.copied += copied;
2020
2021 mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC);
2022 time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time);
2023
2024 rtt_us = msk->rcvq_space.rtt_us;
2025 if (rtt_us && time < (rtt_us >> 3))
2026 return;
2027
2028 rtt_us = 0;
2029 mptcp_for_each_subflow(msk, subflow) {
2030 const struct tcp_sock *tp;
2031 u64 sf_rtt_us;
2032 u32 sf_advmss;
2033
2034 tp = tcp_sk(mptcp_subflow_tcp_sock(subflow));
2035
2036 sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us);
2037 sf_advmss = READ_ONCE(tp->advmss);
2038
2039 rtt_us = max(sf_rtt_us, rtt_us);
2040 advmss = max(sf_advmss, advmss);
2041 scaling_ratio = min(tp->scaling_ratio, scaling_ratio);
2042 }
2043
2044 msk->rcvq_space.rtt_us = rtt_us;
2045 msk->scaling_ratio = scaling_ratio;
2046 if (time < (rtt_us >> 3) || rtt_us == 0)
2047 return;
2048
2049 if (msk->rcvq_space.copied <= msk->rcvq_space.space)
2050 goto new_measure;
2051
2052 msk->rcvq_space.space = msk->rcvq_space.copied;
2053 if (mptcp_rcvbuf_grow(sk)) {
2054
2055 /* Make subflows follow along. If we do not do this, we
2056 * get drops at subflow level if skbs can't be moved to
2057 * the mptcp rx queue fast enough (announced rcv_win can
2058 * exceed ssk->sk_rcvbuf).
2059 */
2060 mptcp_for_each_subflow(msk, subflow) {
2061 struct sock *ssk;
2062 bool slow;
2063
2064 ssk = mptcp_subflow_tcp_sock(subflow);
2065 slow = lock_sock_fast(ssk);
2066 tcp_sk(ssk)->rcvq_space.space = msk->rcvq_space.copied;
2067 tcp_rcvbuf_grow(ssk);
2068 unlock_sock_fast(ssk, slow);
2069 }
2070 }
2071
2072 new_measure:
2073 msk->rcvq_space.copied = 0;
2074 msk->rcvq_space.time = mstamp;
2075 }
2076
2077 static struct mptcp_subflow_context *
__mptcp_first_ready_from(struct mptcp_sock * msk,struct mptcp_subflow_context * subflow)2078 __mptcp_first_ready_from(struct mptcp_sock *msk,
2079 struct mptcp_subflow_context *subflow)
2080 {
2081 struct mptcp_subflow_context *start_subflow = subflow;
2082
2083 while (!READ_ONCE(subflow->data_avail)) {
2084 subflow = mptcp_next_subflow(msk, subflow);
2085 if (subflow == start_subflow)
2086 return NULL;
2087 }
2088 return subflow;
2089 }
2090
__mptcp_move_skbs(struct sock * sk)2091 static bool __mptcp_move_skbs(struct sock *sk)
2092 {
2093 struct mptcp_subflow_context *subflow;
2094 struct mptcp_sock *msk = mptcp_sk(sk);
2095 bool ret = false;
2096
2097 if (list_empty(&msk->conn_list))
2098 return false;
2099
2100 subflow = list_first_entry(&msk->conn_list,
2101 struct mptcp_subflow_context, node);
2102 for (;;) {
2103 struct sock *ssk;
2104 bool slowpath;
2105
2106 /*
2107 * As an optimization avoid traversing the subflows list
2108 * and ev. acquiring the subflow socket lock before baling out
2109 */
2110 if (sk_rmem_alloc_get(sk) > sk->sk_rcvbuf)
2111 break;
2112
2113 subflow = __mptcp_first_ready_from(msk, subflow);
2114 if (!subflow)
2115 break;
2116
2117 ssk = mptcp_subflow_tcp_sock(subflow);
2118 slowpath = lock_sock_fast(ssk);
2119 ret = __mptcp_move_skbs_from_subflow(msk, ssk) || ret;
2120 if (unlikely(ssk->sk_err))
2121 __mptcp_error_report(sk);
2122 unlock_sock_fast(ssk, slowpath);
2123
2124 subflow = mptcp_next_subflow(msk, subflow);
2125 }
2126
2127 __mptcp_ofo_queue(msk);
2128 if (ret)
2129 mptcp_check_data_fin((struct sock *)msk);
2130 return ret;
2131 }
2132
mptcp_inq_hint(const struct sock * sk)2133 static unsigned int mptcp_inq_hint(const struct sock *sk)
2134 {
2135 const struct mptcp_sock *msk = mptcp_sk(sk);
2136 const struct sk_buff *skb;
2137
2138 skb = skb_peek(&sk->sk_receive_queue);
2139 if (skb) {
2140 u64 hint_val = READ_ONCE(msk->ack_seq) - MPTCP_SKB_CB(skb)->map_seq;
2141
2142 if (hint_val >= INT_MAX)
2143 return INT_MAX;
2144
2145 return (unsigned int)hint_val;
2146 }
2147
2148 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
2149 return 1;
2150
2151 return 0;
2152 }
2153
mptcp_recvmsg(struct sock * sk,struct msghdr * msg,size_t len,int flags,int * addr_len)2154 static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
2155 int flags, int *addr_len)
2156 {
2157 struct mptcp_sock *msk = mptcp_sk(sk);
2158 struct scm_timestamping_internal tss;
2159 int copied = 0, cmsg_flags = 0;
2160 int target;
2161 long timeo;
2162
2163 /* MSG_ERRQUEUE is really a no-op till we support IP_RECVERR */
2164 if (unlikely(flags & MSG_ERRQUEUE))
2165 return inet_recv_error(sk, msg, len, addr_len);
2166
2167 lock_sock(sk);
2168 if (unlikely(sk->sk_state == TCP_LISTEN)) {
2169 copied = -ENOTCONN;
2170 goto out_err;
2171 }
2172
2173 mptcp_rps_record_subflows(msk);
2174
2175 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2176
2177 len = min_t(size_t, len, INT_MAX);
2178 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
2179
2180 if (unlikely(msk->recvmsg_inq))
2181 cmsg_flags = MPTCP_CMSG_INQ;
2182
2183 while (copied < len) {
2184 int err, bytes_read;
2185
2186 bytes_read = __mptcp_recvmsg_mskq(sk, msg, len - copied, flags, &tss, &cmsg_flags);
2187 if (unlikely(bytes_read < 0)) {
2188 if (!copied)
2189 copied = bytes_read;
2190 goto out_err;
2191 }
2192
2193 copied += bytes_read;
2194
2195 if (skb_queue_empty(&sk->sk_receive_queue) && __mptcp_move_skbs(sk))
2196 continue;
2197
2198 /* only the MPTCP socket status is relevant here. The exit
2199 * conditions mirror closely tcp_recvmsg()
2200 */
2201 if (copied >= target)
2202 break;
2203
2204 if (copied) {
2205 if (sk->sk_err ||
2206 sk->sk_state == TCP_CLOSE ||
2207 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2208 !timeo ||
2209 signal_pending(current))
2210 break;
2211 } else {
2212 if (sk->sk_err) {
2213 copied = sock_error(sk);
2214 break;
2215 }
2216
2217 if (sk->sk_shutdown & RCV_SHUTDOWN)
2218 break;
2219
2220 if (sk->sk_state == TCP_CLOSE) {
2221 copied = -ENOTCONN;
2222 break;
2223 }
2224
2225 if (!timeo) {
2226 copied = -EAGAIN;
2227 break;
2228 }
2229
2230 if (signal_pending(current)) {
2231 copied = sock_intr_errno(timeo);
2232 break;
2233 }
2234 }
2235
2236 pr_debug("block timeout %ld\n", timeo);
2237 mptcp_cleanup_rbuf(msk, copied);
2238 err = sk_wait_data(sk, &timeo, NULL);
2239 if (err < 0) {
2240 err = copied ? : err;
2241 goto out_err;
2242 }
2243 }
2244
2245 mptcp_cleanup_rbuf(msk, copied);
2246
2247 out_err:
2248 if (cmsg_flags && copied >= 0) {
2249 if (cmsg_flags & MPTCP_CMSG_TS)
2250 tcp_recv_timestamp(msg, sk, &tss);
2251
2252 if (cmsg_flags & MPTCP_CMSG_INQ) {
2253 unsigned int inq = mptcp_inq_hint(sk);
2254
2255 put_cmsg(msg, SOL_TCP, TCP_CM_INQ, sizeof(inq), &inq);
2256 }
2257 }
2258
2259 pr_debug("msk=%p rx queue empty=%d copied=%d\n",
2260 msk, skb_queue_empty(&sk->sk_receive_queue), copied);
2261
2262 release_sock(sk);
2263 return copied;
2264 }
2265
mptcp_retransmit_timer(struct timer_list * t)2266 static void mptcp_retransmit_timer(struct timer_list *t)
2267 {
2268 struct inet_connection_sock *icsk = timer_container_of(icsk, t,
2269 icsk_retransmit_timer);
2270 struct sock *sk = &icsk->icsk_inet.sk;
2271 struct mptcp_sock *msk = mptcp_sk(sk);
2272
2273 bh_lock_sock(sk);
2274 if (!sock_owned_by_user(sk)) {
2275 /* we need a process context to retransmit */
2276 if (!test_and_set_bit(MPTCP_WORK_RTX, &msk->flags))
2277 mptcp_schedule_work(sk);
2278 } else {
2279 /* delegate our work to tcp_release_cb() */
2280 __set_bit(MPTCP_RETRANSMIT, &msk->cb_flags);
2281 }
2282 bh_unlock_sock(sk);
2283 sock_put(sk);
2284 }
2285
mptcp_tout_timer(struct timer_list * t)2286 static void mptcp_tout_timer(struct timer_list *t)
2287 {
2288 struct sock *sk = timer_container_of(sk, t, sk_timer);
2289
2290 mptcp_schedule_work(sk);
2291 sock_put(sk);
2292 }
2293
2294 /* Find an idle subflow. Return NULL if there is unacked data at tcp
2295 * level.
2296 *
2297 * A backup subflow is returned only if that is the only kind available.
2298 */
mptcp_subflow_get_retrans(struct mptcp_sock * msk)2299 struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk)
2300 {
2301 struct sock *backup = NULL, *pick = NULL;
2302 struct mptcp_subflow_context *subflow;
2303 int min_stale_count = INT_MAX;
2304
2305 mptcp_for_each_subflow(msk, subflow) {
2306 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2307
2308 if (!__mptcp_subflow_active(subflow))
2309 continue;
2310
2311 /* still data outstanding at TCP level? skip this */
2312 if (!tcp_rtx_and_write_queues_empty(ssk)) {
2313 mptcp_pm_subflow_chk_stale(msk, ssk);
2314 min_stale_count = min_t(int, min_stale_count, subflow->stale_count);
2315 continue;
2316 }
2317
2318 if (subflow->backup || subflow->request_bkup) {
2319 if (!backup)
2320 backup = ssk;
2321 continue;
2322 }
2323
2324 if (!pick)
2325 pick = ssk;
2326 }
2327
2328 if (pick)
2329 return pick;
2330
2331 /* use backup only if there are no progresses anywhere */
2332 return min_stale_count > 1 ? backup : NULL;
2333 }
2334
__mptcp_retransmit_pending_data(struct sock * sk)2335 bool __mptcp_retransmit_pending_data(struct sock *sk)
2336 {
2337 struct mptcp_data_frag *cur, *rtx_head;
2338 struct mptcp_sock *msk = mptcp_sk(sk);
2339
2340 if (__mptcp_check_fallback(msk))
2341 return false;
2342
2343 /* the closing socket has some data untransmitted and/or unacked:
2344 * some data in the mptcp rtx queue has not really xmitted yet.
2345 * keep it simple and re-inject the whole mptcp level rtx queue
2346 */
2347 mptcp_data_lock(sk);
2348 __mptcp_clean_una_wakeup(sk);
2349 rtx_head = mptcp_rtx_head(sk);
2350 if (!rtx_head) {
2351 mptcp_data_unlock(sk);
2352 return false;
2353 }
2354
2355 msk->recovery_snd_nxt = msk->snd_nxt;
2356 msk->recovery = true;
2357 mptcp_data_unlock(sk);
2358
2359 msk->first_pending = rtx_head;
2360 msk->snd_burst = 0;
2361
2362 /* be sure to clear the "sent status" on all re-injected fragments */
2363 list_for_each_entry(cur, &msk->rtx_queue, list) {
2364 if (!cur->already_sent)
2365 break;
2366 cur->already_sent = 0;
2367 }
2368
2369 return true;
2370 }
2371
2372 /* flags for __mptcp_close_ssk() */
2373 #define MPTCP_CF_PUSH BIT(1)
2374 #define MPTCP_CF_FASTCLOSE BIT(2)
2375
2376 /* be sure to send a reset only if the caller asked for it, also
2377 * clean completely the subflow status when the subflow reaches
2378 * TCP_CLOSE state
2379 */
__mptcp_subflow_disconnect(struct sock * ssk,struct mptcp_subflow_context * subflow,unsigned int flags)2380 static void __mptcp_subflow_disconnect(struct sock *ssk,
2381 struct mptcp_subflow_context *subflow,
2382 unsigned int flags)
2383 {
2384 if (((1 << ssk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) ||
2385 (flags & MPTCP_CF_FASTCLOSE)) {
2386 /* The MPTCP code never wait on the subflow sockets, TCP-level
2387 * disconnect should never fail
2388 */
2389 WARN_ON_ONCE(tcp_disconnect(ssk, 0));
2390 mptcp_subflow_ctx_reset(subflow);
2391 } else {
2392 tcp_shutdown(ssk, SEND_SHUTDOWN);
2393 }
2394 }
2395
2396 /* subflow sockets can be either outgoing (connect) or incoming
2397 * (accept).
2398 *
2399 * Outgoing subflows use in-kernel sockets.
2400 * Incoming subflows do not have their own 'struct socket' allocated,
2401 * so we need to use tcp_close() after detaching them from the mptcp
2402 * parent socket.
2403 */
__mptcp_close_ssk(struct sock * sk,struct sock * ssk,struct mptcp_subflow_context * subflow,unsigned int flags)2404 static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
2405 struct mptcp_subflow_context *subflow,
2406 unsigned int flags)
2407 {
2408 struct mptcp_sock *msk = mptcp_sk(sk);
2409 bool dispose_it, need_push = false;
2410
2411 /* If the first subflow moved to a close state before accept, e.g. due
2412 * to an incoming reset or listener shutdown, the subflow socket is
2413 * already deleted by inet_child_forget() and the mptcp socket can't
2414 * survive too.
2415 */
2416 if (msk->in_accept_queue && msk->first == ssk &&
2417 (sock_flag(sk, SOCK_DEAD) || sock_flag(ssk, SOCK_DEAD))) {
2418 /* ensure later check in mptcp_worker() will dispose the msk */
2419 sock_set_flag(sk, SOCK_DEAD);
2420 mptcp_set_close_tout(sk, tcp_jiffies32 - (mptcp_close_timeout(sk) + 1));
2421 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
2422 mptcp_subflow_drop_ctx(ssk);
2423 goto out_release;
2424 }
2425
2426 dispose_it = msk->free_first || ssk != msk->first;
2427 if (dispose_it)
2428 list_del(&subflow->node);
2429
2430 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
2431
2432 if ((flags & MPTCP_CF_FASTCLOSE) && !__mptcp_check_fallback(msk)) {
2433 /* be sure to force the tcp_close path
2434 * to generate the egress reset
2435 */
2436 ssk->sk_lingertime = 0;
2437 sock_set_flag(ssk, SOCK_LINGER);
2438 subflow->send_fastclose = 1;
2439 }
2440
2441 need_push = (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(sk);
2442 if (!dispose_it) {
2443 __mptcp_subflow_disconnect(ssk, subflow, flags);
2444 release_sock(ssk);
2445
2446 goto out;
2447 }
2448
2449 subflow->disposable = 1;
2450
2451 /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops
2452 * the ssk has been already destroyed, we just need to release the
2453 * reference owned by msk;
2454 */
2455 if (!inet_csk(ssk)->icsk_ulp_ops) {
2456 WARN_ON_ONCE(!sock_flag(ssk, SOCK_DEAD));
2457 kfree_rcu(subflow, rcu);
2458 } else {
2459 /* otherwise tcp will dispose of the ssk and subflow ctx */
2460 __tcp_close(ssk, 0);
2461
2462 /* close acquired an extra ref */
2463 __sock_put(ssk);
2464 }
2465
2466 out_release:
2467 __mptcp_subflow_error_report(sk, ssk);
2468 release_sock(ssk);
2469
2470 sock_put(ssk);
2471
2472 if (ssk == msk->first)
2473 WRITE_ONCE(msk->first, NULL);
2474
2475 out:
2476 __mptcp_sync_sndbuf(sk);
2477 if (need_push)
2478 __mptcp_push_pending(sk, 0);
2479
2480 /* Catch every 'all subflows closed' scenario, including peers silently
2481 * closing them, e.g. due to timeout.
2482 * For established sockets, allow an additional timeout before closing,
2483 * as the protocol can still create more subflows.
2484 */
2485 if (list_is_singular(&msk->conn_list) && msk->first &&
2486 inet_sk_state_load(msk->first) == TCP_CLOSE) {
2487 if (sk->sk_state != TCP_ESTABLISHED ||
2488 msk->in_accept_queue || sock_flag(sk, SOCK_DEAD)) {
2489 mptcp_set_state(sk, TCP_CLOSE);
2490 mptcp_close_wake_up(sk);
2491 } else {
2492 mptcp_start_tout_timer(sk);
2493 }
2494 }
2495 }
2496
mptcp_close_ssk(struct sock * sk,struct sock * ssk,struct mptcp_subflow_context * subflow)2497 void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
2498 struct mptcp_subflow_context *subflow)
2499 {
2500 /* The first subflow can already be closed and still in the list */
2501 if (subflow->close_event_done)
2502 return;
2503
2504 subflow->close_event_done = true;
2505
2506 if (sk->sk_state == TCP_ESTABLISHED)
2507 mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL);
2508
2509 /* subflow aborted before reaching the fully_established status
2510 * attempt the creation of the next subflow
2511 */
2512 mptcp_pm_subflow_check_next(mptcp_sk(sk), subflow);
2513
2514 __mptcp_close_ssk(sk, ssk, subflow, MPTCP_CF_PUSH);
2515 }
2516
mptcp_sync_mss(struct sock * sk,u32 pmtu)2517 static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu)
2518 {
2519 return 0;
2520 }
2521
__mptcp_close_subflow(struct sock * sk)2522 static void __mptcp_close_subflow(struct sock *sk)
2523 {
2524 struct mptcp_subflow_context *subflow, *tmp;
2525 struct mptcp_sock *msk = mptcp_sk(sk);
2526
2527 might_sleep();
2528
2529 mptcp_for_each_subflow_safe(msk, subflow, tmp) {
2530 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2531 int ssk_state = inet_sk_state_load(ssk);
2532
2533 if (ssk_state != TCP_CLOSE &&
2534 (ssk_state != TCP_CLOSE_WAIT ||
2535 inet_sk_state_load(sk) != TCP_ESTABLISHED))
2536 continue;
2537
2538 /* 'subflow_data_ready' will re-sched once rx queue is empty */
2539 if (!skb_queue_empty_lockless(&ssk->sk_receive_queue))
2540 continue;
2541
2542 mptcp_close_ssk(sk, ssk, subflow);
2543 }
2544
2545 }
2546
mptcp_close_tout_expired(const struct sock * sk)2547 static bool mptcp_close_tout_expired(const struct sock *sk)
2548 {
2549 if (!inet_csk(sk)->icsk_mtup.probe_timestamp ||
2550 sk->sk_state == TCP_CLOSE)
2551 return false;
2552
2553 return time_after32(tcp_jiffies32,
2554 inet_csk(sk)->icsk_mtup.probe_timestamp + mptcp_close_timeout(sk));
2555 }
2556
mptcp_check_fastclose(struct mptcp_sock * msk)2557 static void mptcp_check_fastclose(struct mptcp_sock *msk)
2558 {
2559 struct mptcp_subflow_context *subflow, *tmp;
2560 struct sock *sk = (struct sock *)msk;
2561
2562 if (likely(!READ_ONCE(msk->rcv_fastclose)))
2563 return;
2564
2565 mptcp_token_destroy(msk);
2566
2567 mptcp_for_each_subflow_safe(msk, subflow, tmp) {
2568 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
2569 bool slow;
2570
2571 slow = lock_sock_fast(tcp_sk);
2572 if (tcp_sk->sk_state != TCP_CLOSE) {
2573 mptcp_send_active_reset_reason(tcp_sk);
2574 tcp_set_state(tcp_sk, TCP_CLOSE);
2575 }
2576 unlock_sock_fast(tcp_sk, slow);
2577 }
2578
2579 /* Mirror the tcp_reset() error propagation */
2580 switch (sk->sk_state) {
2581 case TCP_SYN_SENT:
2582 WRITE_ONCE(sk->sk_err, ECONNREFUSED);
2583 break;
2584 case TCP_CLOSE_WAIT:
2585 WRITE_ONCE(sk->sk_err, EPIPE);
2586 break;
2587 case TCP_CLOSE:
2588 return;
2589 default:
2590 WRITE_ONCE(sk->sk_err, ECONNRESET);
2591 }
2592
2593 mptcp_set_state(sk, TCP_CLOSE);
2594 WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
2595 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
2596 set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags);
2597
2598 /* the calling mptcp_worker will properly destroy the socket */
2599 if (sock_flag(sk, SOCK_DEAD))
2600 return;
2601
2602 sk->sk_state_change(sk);
2603 sk_error_report(sk);
2604 }
2605
__mptcp_retrans(struct sock * sk)2606 static void __mptcp_retrans(struct sock *sk)
2607 {
2608 struct mptcp_sendmsg_info info = { .data_lock_held = true, };
2609 struct mptcp_sock *msk = mptcp_sk(sk);
2610 struct mptcp_subflow_context *subflow;
2611 struct mptcp_data_frag *dfrag;
2612 struct sock *ssk;
2613 int ret, err;
2614 u16 len = 0;
2615
2616 mptcp_clean_una_wakeup(sk);
2617
2618 /* first check ssk: need to kick "stale" logic */
2619 err = mptcp_sched_get_retrans(msk);
2620 dfrag = mptcp_rtx_head(sk);
2621 if (!dfrag) {
2622 if (mptcp_data_fin_enabled(msk)) {
2623 struct inet_connection_sock *icsk = inet_csk(sk);
2624
2625 WRITE_ONCE(icsk->icsk_retransmits,
2626 icsk->icsk_retransmits + 1);
2627 mptcp_set_datafin_timeout(sk);
2628 mptcp_send_ack(msk);
2629
2630 goto reset_timer;
2631 }
2632
2633 if (!mptcp_send_head(sk))
2634 return;
2635
2636 goto reset_timer;
2637 }
2638
2639 if (err)
2640 goto reset_timer;
2641
2642 mptcp_for_each_subflow(msk, subflow) {
2643 if (READ_ONCE(subflow->scheduled)) {
2644 u16 copied = 0;
2645
2646 mptcp_subflow_set_scheduled(subflow, false);
2647
2648 ssk = mptcp_subflow_tcp_sock(subflow);
2649
2650 lock_sock(ssk);
2651
2652 /* limit retransmission to the bytes already sent on some subflows */
2653 info.sent = 0;
2654 info.limit = READ_ONCE(msk->csum_enabled) ? dfrag->data_len :
2655 dfrag->already_sent;
2656
2657 /*
2658 * make the whole retrans decision, xmit, disallow
2659 * fallback atomic
2660 */
2661 spin_lock_bh(&msk->fallback_lock);
2662 if (__mptcp_check_fallback(msk)) {
2663 spin_unlock_bh(&msk->fallback_lock);
2664 release_sock(ssk);
2665 return;
2666 }
2667
2668 while (info.sent < info.limit) {
2669 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
2670 if (ret <= 0)
2671 break;
2672
2673 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS);
2674 copied += ret;
2675 info.sent += ret;
2676 }
2677 if (copied) {
2678 len = max(copied, len);
2679 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
2680 info.size_goal);
2681 msk->allow_infinite_fallback = false;
2682 }
2683 spin_unlock_bh(&msk->fallback_lock);
2684
2685 release_sock(ssk);
2686 }
2687 }
2688
2689 msk->bytes_retrans += len;
2690 dfrag->already_sent = max(dfrag->already_sent, len);
2691
2692 reset_timer:
2693 mptcp_check_and_set_pending(sk);
2694
2695 if (!mptcp_rtx_timer_pending(sk))
2696 mptcp_reset_rtx_timer(sk);
2697 }
2698
2699 /* schedule the timeout timer for the relevant event: either close timeout
2700 * or mp_fail timeout. The close timeout takes precedence on the mp_fail one
2701 */
mptcp_reset_tout_timer(struct mptcp_sock * msk,unsigned long fail_tout)2702 void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout)
2703 {
2704 struct sock *sk = (struct sock *)msk;
2705 unsigned long timeout, close_timeout;
2706
2707 if (!fail_tout && !inet_csk(sk)->icsk_mtup.probe_timestamp)
2708 return;
2709
2710 close_timeout = (unsigned long)inet_csk(sk)->icsk_mtup.probe_timestamp -
2711 tcp_jiffies32 + jiffies + mptcp_close_timeout(sk);
2712
2713 /* the close timeout takes precedence on the fail one, and here at least one of
2714 * them is active
2715 */
2716 timeout = inet_csk(sk)->icsk_mtup.probe_timestamp ? close_timeout : fail_tout;
2717
2718 sk_reset_timer(sk, &sk->sk_timer, timeout);
2719 }
2720
mptcp_mp_fail_no_response(struct mptcp_sock * msk)2721 static void mptcp_mp_fail_no_response(struct mptcp_sock *msk)
2722 {
2723 struct sock *ssk = msk->first;
2724 bool slow;
2725
2726 if (!ssk)
2727 return;
2728
2729 pr_debug("MP_FAIL doesn't respond, reset the subflow\n");
2730
2731 slow = lock_sock_fast(ssk);
2732 mptcp_subflow_reset(ssk);
2733 WRITE_ONCE(mptcp_subflow_ctx(ssk)->fail_tout, 0);
2734 unlock_sock_fast(ssk, slow);
2735 }
2736
mptcp_do_fastclose(struct sock * sk)2737 static void mptcp_do_fastclose(struct sock *sk)
2738 {
2739 struct mptcp_subflow_context *subflow, *tmp;
2740 struct mptcp_sock *msk = mptcp_sk(sk);
2741
2742 mptcp_set_state(sk, TCP_CLOSE);
2743 mptcp_for_each_subflow_safe(msk, subflow, tmp)
2744 __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow),
2745 subflow, MPTCP_CF_FASTCLOSE);
2746 }
2747
mptcp_worker(struct work_struct * work)2748 static void mptcp_worker(struct work_struct *work)
2749 {
2750 struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
2751 struct sock *sk = (struct sock *)msk;
2752 unsigned long fail_tout;
2753 int state;
2754
2755 lock_sock(sk);
2756 state = sk->sk_state;
2757 if (unlikely((1 << state) & (TCPF_CLOSE | TCPF_LISTEN)))
2758 goto unlock;
2759
2760 mptcp_check_fastclose(msk);
2761
2762 mptcp_pm_worker(msk);
2763
2764 mptcp_check_send_data_fin(sk);
2765 mptcp_check_data_fin_ack(sk);
2766 mptcp_check_data_fin(sk);
2767
2768 if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
2769 __mptcp_close_subflow(sk);
2770
2771 if (mptcp_close_tout_expired(sk)) {
2772 mptcp_do_fastclose(sk);
2773 mptcp_close_wake_up(sk);
2774 }
2775
2776 if (sock_flag(sk, SOCK_DEAD) && sk->sk_state == TCP_CLOSE) {
2777 __mptcp_destroy_sock(sk);
2778 goto unlock;
2779 }
2780
2781 if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
2782 __mptcp_retrans(sk);
2783
2784 fail_tout = msk->first ? READ_ONCE(mptcp_subflow_ctx(msk->first)->fail_tout) : 0;
2785 if (fail_tout && time_after(jiffies, fail_tout))
2786 mptcp_mp_fail_no_response(msk);
2787
2788 unlock:
2789 release_sock(sk);
2790 sock_put(sk);
2791 }
2792
__mptcp_init_sock(struct sock * sk)2793 static void __mptcp_init_sock(struct sock *sk)
2794 {
2795 struct mptcp_sock *msk = mptcp_sk(sk);
2796
2797 INIT_LIST_HEAD(&msk->conn_list);
2798 INIT_LIST_HEAD(&msk->join_list);
2799 INIT_LIST_HEAD(&msk->rtx_queue);
2800 INIT_WORK(&msk->work, mptcp_worker);
2801 msk->out_of_order_queue = RB_ROOT;
2802 msk->first_pending = NULL;
2803 msk->timer_ival = TCP_RTO_MIN;
2804 msk->scaling_ratio = TCP_DEFAULT_SCALING_RATIO;
2805
2806 WRITE_ONCE(msk->first, NULL);
2807 inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss;
2808 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
2809 msk->allow_infinite_fallback = true;
2810 msk->allow_subflows = true;
2811 msk->recovery = false;
2812 msk->subflow_id = 1;
2813 msk->last_data_sent = tcp_jiffies32;
2814 msk->last_data_recv = tcp_jiffies32;
2815 msk->last_ack_recv = tcp_jiffies32;
2816
2817 mptcp_pm_data_init(msk);
2818 spin_lock_init(&msk->fallback_lock);
2819
2820 /* re-use the csk retrans timer for MPTCP-level retrans */
2821 timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0);
2822 timer_setup(&sk->sk_timer, mptcp_tout_timer, 0);
2823 }
2824
mptcp_ca_reset(struct sock * sk)2825 static void mptcp_ca_reset(struct sock *sk)
2826 {
2827 struct inet_connection_sock *icsk = inet_csk(sk);
2828
2829 tcp_assign_congestion_control(sk);
2830 strscpy(mptcp_sk(sk)->ca_name, icsk->icsk_ca_ops->name,
2831 sizeof(mptcp_sk(sk)->ca_name));
2832
2833 /* no need to keep a reference to the ops, the name will suffice */
2834 tcp_cleanup_congestion_control(sk);
2835 icsk->icsk_ca_ops = NULL;
2836 }
2837
mptcp_init_sock(struct sock * sk)2838 static int mptcp_init_sock(struct sock *sk)
2839 {
2840 struct net *net = sock_net(sk);
2841 int ret;
2842
2843 __mptcp_init_sock(sk);
2844
2845 if (!mptcp_is_enabled(net))
2846 return -ENOPROTOOPT;
2847
2848 if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net))
2849 return -ENOMEM;
2850
2851 rcu_read_lock();
2852 ret = mptcp_init_sched(mptcp_sk(sk),
2853 mptcp_sched_find(mptcp_get_scheduler(net)));
2854 rcu_read_unlock();
2855 if (ret)
2856 return ret;
2857
2858 set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags);
2859
2860 /* fetch the ca name; do it outside __mptcp_init_sock(), so that clone will
2861 * propagate the correct value
2862 */
2863 mptcp_ca_reset(sk);
2864
2865 sk_sockets_allocated_inc(sk);
2866 sk->sk_rcvbuf = READ_ONCE(net->ipv4.sysctl_tcp_rmem[1]);
2867 sk->sk_sndbuf = READ_ONCE(net->ipv4.sysctl_tcp_wmem[1]);
2868
2869 return 0;
2870 }
2871
__mptcp_clear_xmit(struct sock * sk)2872 static void __mptcp_clear_xmit(struct sock *sk)
2873 {
2874 struct mptcp_sock *msk = mptcp_sk(sk);
2875 struct mptcp_data_frag *dtmp, *dfrag;
2876
2877 WRITE_ONCE(msk->first_pending, NULL);
2878 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list)
2879 dfrag_clear(sk, dfrag);
2880 }
2881
mptcp_cancel_work(struct sock * sk)2882 void mptcp_cancel_work(struct sock *sk)
2883 {
2884 struct mptcp_sock *msk = mptcp_sk(sk);
2885
2886 if (cancel_work_sync(&msk->work))
2887 __sock_put(sk);
2888 }
2889
mptcp_subflow_shutdown(struct sock * sk,struct sock * ssk,int how)2890 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how)
2891 {
2892 lock_sock(ssk);
2893
2894 switch (ssk->sk_state) {
2895 case TCP_LISTEN:
2896 if (!(how & RCV_SHUTDOWN))
2897 break;
2898 fallthrough;
2899 case TCP_SYN_SENT:
2900 WARN_ON_ONCE(tcp_disconnect(ssk, O_NONBLOCK));
2901 break;
2902 default:
2903 if (__mptcp_check_fallback(mptcp_sk(sk))) {
2904 pr_debug("Fallback\n");
2905 ssk->sk_shutdown |= how;
2906 tcp_shutdown(ssk, how);
2907
2908 /* simulate the data_fin ack reception to let the state
2909 * machine move forward
2910 */
2911 WRITE_ONCE(mptcp_sk(sk)->snd_una, mptcp_sk(sk)->snd_nxt);
2912 mptcp_schedule_work(sk);
2913 } else {
2914 pr_debug("Sending DATA_FIN on subflow %p\n", ssk);
2915 tcp_send_ack(ssk);
2916 if (!mptcp_rtx_timer_pending(sk))
2917 mptcp_reset_rtx_timer(sk);
2918 }
2919 break;
2920 }
2921
2922 release_sock(ssk);
2923 }
2924
mptcp_set_state(struct sock * sk,int state)2925 void mptcp_set_state(struct sock *sk, int state)
2926 {
2927 int oldstate = sk->sk_state;
2928
2929 switch (state) {
2930 case TCP_ESTABLISHED:
2931 if (oldstate != TCP_ESTABLISHED)
2932 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_CURRESTAB);
2933 break;
2934 case TCP_CLOSE_WAIT:
2935 /* Unlike TCP, MPTCP sk would not have the TCP_SYN_RECV state:
2936 * MPTCP "accepted" sockets will be created later on. So no
2937 * transition from TCP_SYN_RECV to TCP_CLOSE_WAIT.
2938 */
2939 break;
2940 default:
2941 if (oldstate == TCP_ESTABLISHED || oldstate == TCP_CLOSE_WAIT)
2942 MPTCP_DEC_STATS(sock_net(sk), MPTCP_MIB_CURRESTAB);
2943 }
2944
2945 inet_sk_state_store(sk, state);
2946 }
2947
2948 static const unsigned char new_state[16] = {
2949 /* current state: new state: action: */
2950 [0 /* (Invalid) */] = TCP_CLOSE,
2951 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2952 [TCP_SYN_SENT] = TCP_CLOSE,
2953 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2954 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1,
2955 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2,
2956 [TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */
2957 [TCP_CLOSE] = TCP_CLOSE,
2958 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN,
2959 [TCP_LAST_ACK] = TCP_LAST_ACK,
2960 [TCP_LISTEN] = TCP_CLOSE,
2961 [TCP_CLOSING] = TCP_CLOSING,
2962 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */
2963 };
2964
mptcp_close_state(struct sock * sk)2965 static int mptcp_close_state(struct sock *sk)
2966 {
2967 int next = (int)new_state[sk->sk_state];
2968 int ns = next & TCP_STATE_MASK;
2969
2970 mptcp_set_state(sk, ns);
2971
2972 return next & TCP_ACTION_FIN;
2973 }
2974
mptcp_check_send_data_fin(struct sock * sk)2975 static void mptcp_check_send_data_fin(struct sock *sk)
2976 {
2977 struct mptcp_subflow_context *subflow;
2978 struct mptcp_sock *msk = mptcp_sk(sk);
2979
2980 pr_debug("msk=%p snd_data_fin_enable=%d pending=%d snd_nxt=%llu write_seq=%llu\n",
2981 msk, msk->snd_data_fin_enable, !!mptcp_send_head(sk),
2982 msk->snd_nxt, msk->write_seq);
2983
2984 /* we still need to enqueue subflows or not really shutting down,
2985 * skip this
2986 */
2987 if (!msk->snd_data_fin_enable || msk->snd_nxt + 1 != msk->write_seq ||
2988 mptcp_send_head(sk))
2989 return;
2990
2991 WRITE_ONCE(msk->snd_nxt, msk->write_seq);
2992
2993 mptcp_for_each_subflow(msk, subflow) {
2994 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
2995
2996 mptcp_subflow_shutdown(sk, tcp_sk, SEND_SHUTDOWN);
2997 }
2998 }
2999
__mptcp_wr_shutdown(struct sock * sk)3000 static void __mptcp_wr_shutdown(struct sock *sk)
3001 {
3002 struct mptcp_sock *msk = mptcp_sk(sk);
3003
3004 pr_debug("msk=%p snd_data_fin_enable=%d shutdown=%x state=%d pending=%d\n",
3005 msk, msk->snd_data_fin_enable, sk->sk_shutdown, sk->sk_state,
3006 !!mptcp_send_head(sk));
3007
3008 /* will be ignored by fallback sockets */
3009 WRITE_ONCE(msk->write_seq, msk->write_seq + 1);
3010 WRITE_ONCE(msk->snd_data_fin_enable, 1);
3011
3012 mptcp_check_send_data_fin(sk);
3013 }
3014
__mptcp_destroy_sock(struct sock * sk)3015 static void __mptcp_destroy_sock(struct sock *sk)
3016 {
3017 struct mptcp_sock *msk = mptcp_sk(sk);
3018
3019 pr_debug("msk=%p\n", msk);
3020
3021 might_sleep();
3022
3023 mptcp_stop_rtx_timer(sk);
3024 sk_stop_timer(sk, &sk->sk_timer);
3025 msk->pm.status = 0;
3026 mptcp_release_sched(msk);
3027
3028 sk->sk_prot->destroy(sk);
3029
3030 sk_stream_kill_queues(sk);
3031 xfrm_sk_free_policy(sk);
3032
3033 sock_put(sk);
3034 }
3035
__mptcp_unaccepted_force_close(struct sock * sk)3036 void __mptcp_unaccepted_force_close(struct sock *sk)
3037 {
3038 sock_set_flag(sk, SOCK_DEAD);
3039 mptcp_do_fastclose(sk);
3040 __mptcp_destroy_sock(sk);
3041 }
3042
mptcp_check_readable(struct sock * sk)3043 static __poll_t mptcp_check_readable(struct sock *sk)
3044 {
3045 return mptcp_epollin_ready(sk) ? EPOLLIN | EPOLLRDNORM : 0;
3046 }
3047
mptcp_check_listen_stop(struct sock * sk)3048 static void mptcp_check_listen_stop(struct sock *sk)
3049 {
3050 struct sock *ssk;
3051
3052 if (inet_sk_state_load(sk) != TCP_LISTEN)
3053 return;
3054
3055 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
3056 ssk = mptcp_sk(sk)->first;
3057 if (WARN_ON_ONCE(!ssk || inet_sk_state_load(ssk) != TCP_LISTEN))
3058 return;
3059
3060 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
3061 tcp_set_state(ssk, TCP_CLOSE);
3062 mptcp_subflow_queue_clean(sk, ssk);
3063 inet_csk_listen_stop(ssk);
3064 mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CLOSED);
3065 release_sock(ssk);
3066 }
3067
__mptcp_close(struct sock * sk,long timeout)3068 bool __mptcp_close(struct sock *sk, long timeout)
3069 {
3070 struct mptcp_subflow_context *subflow;
3071 struct mptcp_sock *msk = mptcp_sk(sk);
3072 bool do_cancel_work = false;
3073 int subflows_alive = 0;
3074
3075 WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
3076
3077 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) {
3078 mptcp_check_listen_stop(sk);
3079 mptcp_set_state(sk, TCP_CLOSE);
3080 goto cleanup;
3081 }
3082
3083 if (mptcp_data_avail(msk) || timeout < 0) {
3084 /* If the msk has read data, or the caller explicitly ask it,
3085 * do the MPTCP equivalent of TCP reset, aka MPTCP fastclose
3086 */
3087 mptcp_do_fastclose(sk);
3088 timeout = 0;
3089 } else if (mptcp_close_state(sk)) {
3090 __mptcp_wr_shutdown(sk);
3091 }
3092
3093 sk_stream_wait_close(sk, timeout);
3094
3095 cleanup:
3096 /* orphan all the subflows */
3097 mptcp_for_each_subflow(msk, subflow) {
3098 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3099 bool slow = lock_sock_fast_nested(ssk);
3100
3101 subflows_alive += ssk->sk_state != TCP_CLOSE;
3102
3103 /* since the close timeout takes precedence on the fail one,
3104 * cancel the latter
3105 */
3106 if (ssk == msk->first)
3107 subflow->fail_tout = 0;
3108
3109 /* detach from the parent socket, but allow data_ready to
3110 * push incoming data into the mptcp stack, to properly ack it
3111 */
3112 ssk->sk_socket = NULL;
3113 ssk->sk_wq = NULL;
3114 unlock_sock_fast(ssk, slow);
3115 }
3116 sock_orphan(sk);
3117
3118 /* all the subflows are closed, only timeout can change the msk
3119 * state, let's not keep resources busy for no reasons
3120 */
3121 if (subflows_alive == 0)
3122 mptcp_set_state(sk, TCP_CLOSE);
3123
3124 sock_hold(sk);
3125 pr_debug("msk=%p state=%d\n", sk, sk->sk_state);
3126 mptcp_pm_connection_closed(msk);
3127
3128 if (sk->sk_state == TCP_CLOSE) {
3129 __mptcp_destroy_sock(sk);
3130 do_cancel_work = true;
3131 } else {
3132 mptcp_start_tout_timer(sk);
3133 }
3134
3135 return do_cancel_work;
3136 }
3137
mptcp_close(struct sock * sk,long timeout)3138 static void mptcp_close(struct sock *sk, long timeout)
3139 {
3140 bool do_cancel_work;
3141
3142 lock_sock(sk);
3143
3144 do_cancel_work = __mptcp_close(sk, timeout);
3145 release_sock(sk);
3146 if (do_cancel_work)
3147 mptcp_cancel_work(sk);
3148
3149 sock_put(sk);
3150 }
3151
mptcp_copy_inaddrs(struct sock * msk,const struct sock * ssk)3152 static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk)
3153 {
3154 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
3155 const struct ipv6_pinfo *ssk6 = inet6_sk(ssk);
3156 struct ipv6_pinfo *msk6 = inet6_sk(msk);
3157
3158 msk->sk_v6_daddr = ssk->sk_v6_daddr;
3159 msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr;
3160
3161 if (msk6 && ssk6) {
3162 msk6->saddr = ssk6->saddr;
3163 msk6->flow_label = ssk6->flow_label;
3164 }
3165 #endif
3166
3167 inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num;
3168 inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport;
3169 inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport;
3170 inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr;
3171 inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr;
3172 inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr;
3173 }
3174
mptcp_disconnect(struct sock * sk,int flags)3175 static int mptcp_disconnect(struct sock *sk, int flags)
3176 {
3177 struct mptcp_sock *msk = mptcp_sk(sk);
3178
3179 /* We are on the fastopen error path. We can't call straight into the
3180 * subflows cleanup code due to lock nesting (we are already under
3181 * msk->firstsocket lock).
3182 */
3183 if (msk->fastopening)
3184 return -EBUSY;
3185
3186 mptcp_check_listen_stop(sk);
3187 mptcp_set_state(sk, TCP_CLOSE);
3188
3189 mptcp_stop_rtx_timer(sk);
3190 mptcp_stop_tout_timer(sk);
3191
3192 mptcp_pm_connection_closed(msk);
3193
3194 /* msk->subflow is still intact, the following will not free the first
3195 * subflow
3196 */
3197 mptcp_destroy_common(msk, MPTCP_CF_FASTCLOSE);
3198
3199 /* The first subflow is already in TCP_CLOSE status, the following
3200 * can't overlap with a fallback anymore
3201 */
3202 spin_lock_bh(&msk->fallback_lock);
3203 msk->allow_subflows = true;
3204 msk->allow_infinite_fallback = true;
3205 WRITE_ONCE(msk->flags, 0);
3206 spin_unlock_bh(&msk->fallback_lock);
3207
3208 msk->cb_flags = 0;
3209 msk->recovery = false;
3210 WRITE_ONCE(msk->can_ack, false);
3211 WRITE_ONCE(msk->fully_established, false);
3212 WRITE_ONCE(msk->rcv_data_fin, false);
3213 WRITE_ONCE(msk->snd_data_fin_enable, false);
3214 WRITE_ONCE(msk->rcv_fastclose, false);
3215 WRITE_ONCE(msk->use_64bit_ack, false);
3216 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
3217 mptcp_pm_data_reset(msk);
3218 mptcp_ca_reset(sk);
3219 msk->bytes_consumed = 0;
3220 msk->bytes_acked = 0;
3221 msk->bytes_received = 0;
3222 msk->bytes_sent = 0;
3223 msk->bytes_retrans = 0;
3224 msk->rcvspace_init = 0;
3225
3226 WRITE_ONCE(sk->sk_shutdown, 0);
3227 sk_error_report(sk);
3228 return 0;
3229 }
3230
3231 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
mptcp_inet6_sk(const struct sock * sk)3232 static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk)
3233 {
3234 struct mptcp6_sock *msk6 = container_of(mptcp_sk(sk), struct mptcp6_sock, msk);
3235
3236 return &msk6->np;
3237 }
3238
mptcp_copy_ip6_options(struct sock * newsk,const struct sock * sk)3239 static void mptcp_copy_ip6_options(struct sock *newsk, const struct sock *sk)
3240 {
3241 const struct ipv6_pinfo *np = inet6_sk(sk);
3242 struct ipv6_txoptions *opt;
3243 struct ipv6_pinfo *newnp;
3244
3245 newnp = inet6_sk(newsk);
3246
3247 rcu_read_lock();
3248 opt = rcu_dereference(np->opt);
3249 if (opt) {
3250 opt = ipv6_dup_options(newsk, opt);
3251 if (!opt)
3252 net_warn_ratelimited("%s: Failed to copy ip6 options\n", __func__);
3253 }
3254 RCU_INIT_POINTER(newnp->opt, opt);
3255 rcu_read_unlock();
3256 }
3257 #endif
3258
mptcp_copy_ip_options(struct sock * newsk,const struct sock * sk)3259 static void mptcp_copy_ip_options(struct sock *newsk, const struct sock *sk)
3260 {
3261 struct ip_options_rcu *inet_opt, *newopt = NULL;
3262 const struct inet_sock *inet = inet_sk(sk);
3263 struct inet_sock *newinet;
3264
3265 newinet = inet_sk(newsk);
3266
3267 rcu_read_lock();
3268 inet_opt = rcu_dereference(inet->inet_opt);
3269 if (inet_opt) {
3270 newopt = sock_kmemdup(newsk, inet_opt, sizeof(*inet_opt) +
3271 inet_opt->opt.optlen, GFP_ATOMIC);
3272 if (!newopt)
3273 net_warn_ratelimited("%s: Failed to copy ip options\n", __func__);
3274 }
3275 RCU_INIT_POINTER(newinet->inet_opt, newopt);
3276 rcu_read_unlock();
3277 }
3278
mptcp_sk_clone_init(const struct sock * sk,const struct mptcp_options_received * mp_opt,struct sock * ssk,struct request_sock * req)3279 struct sock *mptcp_sk_clone_init(const struct sock *sk,
3280 const struct mptcp_options_received *mp_opt,
3281 struct sock *ssk,
3282 struct request_sock *req)
3283 {
3284 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
3285 struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC);
3286 struct mptcp_subflow_context *subflow;
3287 struct mptcp_sock *msk;
3288
3289 if (!nsk)
3290 return NULL;
3291
3292 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
3293 if (nsk->sk_family == AF_INET6)
3294 inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk);
3295 #endif
3296
3297 __mptcp_init_sock(nsk);
3298
3299 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
3300 if (nsk->sk_family == AF_INET6)
3301 mptcp_copy_ip6_options(nsk, sk);
3302 else
3303 #endif
3304 mptcp_copy_ip_options(nsk, sk);
3305
3306 msk = mptcp_sk(nsk);
3307 WRITE_ONCE(msk->local_key, subflow_req->local_key);
3308 WRITE_ONCE(msk->token, subflow_req->token);
3309 msk->in_accept_queue = 1;
3310 WRITE_ONCE(msk->fully_established, false);
3311 if (mp_opt->suboptions & OPTION_MPTCP_CSUMREQD)
3312 WRITE_ONCE(msk->csum_enabled, true);
3313
3314 WRITE_ONCE(msk->write_seq, subflow_req->idsn + 1);
3315 WRITE_ONCE(msk->snd_nxt, msk->write_seq);
3316 WRITE_ONCE(msk->snd_una, msk->write_seq);
3317 WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd);
3318 msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq;
3319 mptcp_init_sched(msk, mptcp_sk(sk)->sched);
3320
3321 /* passive msk is created after the first/MPC subflow */
3322 msk->subflow_id = 2;
3323
3324 sock_reset_flag(nsk, SOCK_RCU_FREE);
3325 security_inet_csk_clone(nsk, req);
3326
3327 /* this can't race with mptcp_close(), as the msk is
3328 * not yet exposted to user-space
3329 */
3330 mptcp_set_state(nsk, TCP_ESTABLISHED);
3331
3332 /* The msk maintain a ref to each subflow in the connections list */
3333 WRITE_ONCE(msk->first, ssk);
3334 subflow = mptcp_subflow_ctx(ssk);
3335 list_add(&subflow->node, &msk->conn_list);
3336 sock_hold(ssk);
3337
3338 /* new mpc subflow takes ownership of the newly
3339 * created mptcp socket
3340 */
3341 mptcp_token_accept(subflow_req, msk);
3342
3343 /* set msk addresses early to ensure mptcp_pm_get_local_id()
3344 * uses the correct data
3345 */
3346 mptcp_copy_inaddrs(nsk, ssk);
3347 __mptcp_propagate_sndbuf(nsk, ssk);
3348
3349 mptcp_rcv_space_init(msk, ssk);
3350
3351 if (mp_opt->suboptions & OPTION_MPTCP_MPC_ACK)
3352 __mptcp_subflow_fully_established(msk, subflow, mp_opt);
3353 bh_unlock_sock(nsk);
3354
3355 /* note: the newly allocated socket refcount is 2 now */
3356 return nsk;
3357 }
3358
mptcp_rcv_space_init(struct mptcp_sock * msk,const struct sock * ssk)3359 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk)
3360 {
3361 const struct tcp_sock *tp = tcp_sk(ssk);
3362
3363 msk->rcvspace_init = 1;
3364 msk->rcvq_space.copied = 0;
3365 msk->rcvq_space.rtt_us = 0;
3366
3367 msk->rcvq_space.time = tp->tcp_mstamp;
3368
3369 /* initial rcv_space offering made to peer */
3370 msk->rcvq_space.space = min_t(u32, tp->rcv_wnd,
3371 TCP_INIT_CWND * tp->advmss);
3372 if (msk->rcvq_space.space == 0)
3373 msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT;
3374 }
3375
mptcp_destroy_common(struct mptcp_sock * msk,unsigned int flags)3376 void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags)
3377 {
3378 struct mptcp_subflow_context *subflow, *tmp;
3379 struct sock *sk = (struct sock *)msk;
3380
3381 __mptcp_clear_xmit(sk);
3382
3383 /* join list will be eventually flushed (with rst) at sock lock release time */
3384 mptcp_for_each_subflow_safe(msk, subflow, tmp)
3385 __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), subflow, flags);
3386
3387 __skb_queue_purge(&sk->sk_receive_queue);
3388 skb_rbtree_purge(&msk->out_of_order_queue);
3389
3390 /* move all the rx fwd alloc into the sk_mem_reclaim_final in
3391 * inet_sock_destruct() will dispose it
3392 */
3393 mptcp_token_destroy(msk);
3394 mptcp_pm_destroy(msk);
3395 }
3396
mptcp_destroy(struct sock * sk)3397 static void mptcp_destroy(struct sock *sk)
3398 {
3399 struct mptcp_sock *msk = mptcp_sk(sk);
3400
3401 /* allow the following to close even the initial subflow */
3402 msk->free_first = 1;
3403 mptcp_destroy_common(msk, 0);
3404 sk_sockets_allocated_dec(sk);
3405 }
3406
__mptcp_data_acked(struct sock * sk)3407 void __mptcp_data_acked(struct sock *sk)
3408 {
3409 if (!sock_owned_by_user(sk))
3410 __mptcp_clean_una(sk);
3411 else
3412 __set_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->cb_flags);
3413 }
3414
__mptcp_check_push(struct sock * sk,struct sock * ssk)3415 void __mptcp_check_push(struct sock *sk, struct sock *ssk)
3416 {
3417 if (!mptcp_send_head(sk))
3418 return;
3419
3420 if (!sock_owned_by_user(sk))
3421 __mptcp_subflow_push_pending(sk, ssk, false);
3422 else
3423 __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags);
3424 }
3425
3426 #define MPTCP_FLAGS_PROCESS_CTX_NEED (BIT(MPTCP_PUSH_PENDING) | \
3427 BIT(MPTCP_RETRANSMIT) | \
3428 BIT(MPTCP_FLUSH_JOIN_LIST) | \
3429 BIT(MPTCP_DEQUEUE))
3430
3431 /* processes deferred events and flush wmem */
mptcp_release_cb(struct sock * sk)3432 static void mptcp_release_cb(struct sock *sk)
3433 __must_hold(&sk->sk_lock.slock)
3434 {
3435 struct mptcp_sock *msk = mptcp_sk(sk);
3436
3437 for (;;) {
3438 unsigned long flags = (msk->cb_flags & MPTCP_FLAGS_PROCESS_CTX_NEED);
3439 struct list_head join_list;
3440
3441 if (!flags)
3442 break;
3443
3444 INIT_LIST_HEAD(&join_list);
3445 list_splice_init(&msk->join_list, &join_list);
3446
3447 /* the following actions acquire the subflow socket lock
3448 *
3449 * 1) can't be invoked in atomic scope
3450 * 2) must avoid ABBA deadlock with msk socket spinlock: the RX
3451 * datapath acquires the msk socket spinlock while helding
3452 * the subflow socket lock
3453 */
3454 msk->cb_flags &= ~flags;
3455 spin_unlock_bh(&sk->sk_lock.slock);
3456
3457 if (flags & BIT(MPTCP_FLUSH_JOIN_LIST))
3458 __mptcp_flush_join_list(sk, &join_list);
3459 if (flags & BIT(MPTCP_PUSH_PENDING))
3460 __mptcp_push_pending(sk, 0);
3461 if (flags & BIT(MPTCP_RETRANSMIT))
3462 __mptcp_retrans(sk);
3463 if ((flags & BIT(MPTCP_DEQUEUE)) && __mptcp_move_skbs(sk)) {
3464 /* notify ack seq update */
3465 mptcp_cleanup_rbuf(msk, 0);
3466 sk->sk_data_ready(sk);
3467 }
3468
3469 cond_resched();
3470 spin_lock_bh(&sk->sk_lock.slock);
3471 }
3472
3473 if (__test_and_clear_bit(MPTCP_CLEAN_UNA, &msk->cb_flags))
3474 __mptcp_clean_una_wakeup(sk);
3475 if (unlikely(msk->cb_flags)) {
3476 /* be sure to sync the msk state before taking actions
3477 * depending on sk_state (MPTCP_ERROR_REPORT)
3478 * On sk release avoid actions depending on the first subflow
3479 */
3480 if (__test_and_clear_bit(MPTCP_SYNC_STATE, &msk->cb_flags) && msk->first)
3481 __mptcp_sync_state(sk, msk->pending_state);
3482 if (__test_and_clear_bit(MPTCP_ERROR_REPORT, &msk->cb_flags))
3483 __mptcp_error_report(sk);
3484 if (__test_and_clear_bit(MPTCP_SYNC_SNDBUF, &msk->cb_flags))
3485 __mptcp_sync_sndbuf(sk);
3486 }
3487 }
3488
3489 /* MP_JOIN client subflow must wait for 4th ack before sending any data:
3490 * TCP can't schedule delack timer before the subflow is fully established.
3491 * MPTCP uses the delack timer to do 3rd ack retransmissions
3492 */
schedule_3rdack_retransmission(struct sock * ssk)3493 static void schedule_3rdack_retransmission(struct sock *ssk)
3494 {
3495 struct inet_connection_sock *icsk = inet_csk(ssk);
3496 struct tcp_sock *tp = tcp_sk(ssk);
3497 unsigned long timeout;
3498
3499 if (READ_ONCE(mptcp_subflow_ctx(ssk)->fully_established))
3500 return;
3501
3502 /* reschedule with a timeout above RTT, as we must look only for drop */
3503 if (tp->srtt_us)
3504 timeout = usecs_to_jiffies(tp->srtt_us >> (3 - 1));
3505 else
3506 timeout = TCP_TIMEOUT_INIT;
3507 timeout += jiffies;
3508
3509 WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER);
3510 smp_store_release(&icsk->icsk_ack.pending,
3511 icsk->icsk_ack.pending | ICSK_ACK_SCHED | ICSK_ACK_TIMER);
3512 sk_reset_timer(ssk, &icsk->icsk_delack_timer, timeout);
3513 }
3514
mptcp_subflow_process_delegated(struct sock * ssk,long status)3515 void mptcp_subflow_process_delegated(struct sock *ssk, long status)
3516 {
3517 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
3518 struct sock *sk = subflow->conn;
3519
3520 if (status & BIT(MPTCP_DELEGATE_SEND)) {
3521 mptcp_data_lock(sk);
3522 if (!sock_owned_by_user(sk))
3523 __mptcp_subflow_push_pending(sk, ssk, true);
3524 else
3525 __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags);
3526 mptcp_data_unlock(sk);
3527 }
3528 if (status & BIT(MPTCP_DELEGATE_SNDBUF)) {
3529 mptcp_data_lock(sk);
3530 if (!sock_owned_by_user(sk))
3531 __mptcp_sync_sndbuf(sk);
3532 else
3533 __set_bit(MPTCP_SYNC_SNDBUF, &mptcp_sk(sk)->cb_flags);
3534 mptcp_data_unlock(sk);
3535 }
3536 if (status & BIT(MPTCP_DELEGATE_ACK))
3537 schedule_3rdack_retransmission(ssk);
3538 }
3539
mptcp_hash(struct sock * sk)3540 static int mptcp_hash(struct sock *sk)
3541 {
3542 /* should never be called,
3543 * we hash the TCP subflows not the MPTCP socket
3544 */
3545 WARN_ON_ONCE(1);
3546 return 0;
3547 }
3548
mptcp_unhash(struct sock * sk)3549 static void mptcp_unhash(struct sock *sk)
3550 {
3551 /* called from sk_common_release(), but nothing to do here */
3552 }
3553
mptcp_get_port(struct sock * sk,unsigned short snum)3554 static int mptcp_get_port(struct sock *sk, unsigned short snum)
3555 {
3556 struct mptcp_sock *msk = mptcp_sk(sk);
3557
3558 pr_debug("msk=%p, ssk=%p\n", msk, msk->first);
3559 if (WARN_ON_ONCE(!msk->first))
3560 return -EINVAL;
3561
3562 return inet_csk_get_port(msk->first, snum);
3563 }
3564
mptcp_finish_connect(struct sock * ssk)3565 void mptcp_finish_connect(struct sock *ssk)
3566 {
3567 struct mptcp_subflow_context *subflow;
3568 struct mptcp_sock *msk;
3569 struct sock *sk;
3570
3571 subflow = mptcp_subflow_ctx(ssk);
3572 sk = subflow->conn;
3573 msk = mptcp_sk(sk);
3574
3575 pr_debug("msk=%p, token=%u\n", sk, subflow->token);
3576
3577 subflow->map_seq = subflow->iasn;
3578 subflow->map_subflow_seq = 1;
3579
3580 /* the socket is not connected yet, no msk/subflow ops can access/race
3581 * accessing the field below
3582 */
3583 WRITE_ONCE(msk->local_key, subflow->local_key);
3584
3585 mptcp_pm_new_connection(msk, ssk, 0);
3586 }
3587
mptcp_sock_graft(struct sock * sk,struct socket * parent)3588 void mptcp_sock_graft(struct sock *sk, struct socket *parent)
3589 {
3590 write_lock_bh(&sk->sk_callback_lock);
3591 rcu_assign_pointer(sk->sk_wq, &parent->wq);
3592 sk_set_socket(sk, parent);
3593 write_unlock_bh(&sk->sk_callback_lock);
3594 }
3595
mptcp_finish_join(struct sock * ssk)3596 bool mptcp_finish_join(struct sock *ssk)
3597 {
3598 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
3599 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
3600 struct sock *parent = (void *)msk;
3601 bool ret = true;
3602
3603 pr_debug("msk=%p, subflow=%p\n", msk, subflow);
3604
3605 /* mptcp socket already closing? */
3606 if (!mptcp_is_fully_established(parent)) {
3607 subflow->reset_reason = MPTCP_RST_EMPTCP;
3608 return false;
3609 }
3610
3611 /* active subflow, already present inside the conn_list */
3612 if (!list_empty(&subflow->node)) {
3613 spin_lock_bh(&msk->fallback_lock);
3614 if (!msk->allow_subflows) {
3615 spin_unlock_bh(&msk->fallback_lock);
3616 return false;
3617 }
3618 mptcp_subflow_joined(msk, ssk);
3619 spin_unlock_bh(&msk->fallback_lock);
3620 mptcp_propagate_sndbuf(parent, ssk);
3621 return true;
3622 }
3623
3624 if (!mptcp_pm_allow_new_subflow(msk)) {
3625 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_JOINREJECTED);
3626 goto err_prohibited;
3627 }
3628
3629 /* If we can't acquire msk socket lock here, let the release callback
3630 * handle it
3631 */
3632 mptcp_data_lock(parent);
3633 if (!sock_owned_by_user(parent)) {
3634 ret = __mptcp_finish_join(msk, ssk);
3635 if (ret) {
3636 sock_hold(ssk);
3637 list_add_tail(&subflow->node, &msk->conn_list);
3638 }
3639 } else {
3640 sock_hold(ssk);
3641 list_add_tail(&subflow->node, &msk->join_list);
3642 __set_bit(MPTCP_FLUSH_JOIN_LIST, &msk->cb_flags);
3643 }
3644 mptcp_data_unlock(parent);
3645
3646 if (!ret) {
3647 err_prohibited:
3648 subflow->reset_reason = MPTCP_RST_EPROHIBIT;
3649 return false;
3650 }
3651
3652 return true;
3653 }
3654
mptcp_shutdown(struct sock * sk,int how)3655 static void mptcp_shutdown(struct sock *sk, int how)
3656 {
3657 pr_debug("sk=%p, how=%d\n", sk, how);
3658
3659 if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk))
3660 __mptcp_wr_shutdown(sk);
3661 }
3662
mptcp_ioctl_outq(const struct mptcp_sock * msk,u64 v)3663 static int mptcp_ioctl_outq(const struct mptcp_sock *msk, u64 v)
3664 {
3665 const struct sock *sk = (void *)msk;
3666 u64 delta;
3667
3668 if (sk->sk_state == TCP_LISTEN)
3669 return -EINVAL;
3670
3671 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
3672 return 0;
3673
3674 delta = msk->write_seq - v;
3675 if (__mptcp_check_fallback(msk) && msk->first) {
3676 struct tcp_sock *tp = tcp_sk(msk->first);
3677
3678 /* the first subflow is disconnected after close - see
3679 * __mptcp_close_ssk(). tcp_disconnect() moves the write_seq
3680 * so ignore that status, too.
3681 */
3682 if (!((1 << msk->first->sk_state) &
3683 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE)))
3684 delta += READ_ONCE(tp->write_seq) - tp->snd_una;
3685 }
3686 if (delta > INT_MAX)
3687 delta = INT_MAX;
3688
3689 return (int)delta;
3690 }
3691
mptcp_ioctl(struct sock * sk,int cmd,int * karg)3692 static int mptcp_ioctl(struct sock *sk, int cmd, int *karg)
3693 {
3694 struct mptcp_sock *msk = mptcp_sk(sk);
3695 bool slow;
3696
3697 switch (cmd) {
3698 case SIOCINQ:
3699 if (sk->sk_state == TCP_LISTEN)
3700 return -EINVAL;
3701
3702 lock_sock(sk);
3703 if (__mptcp_move_skbs(sk))
3704 mptcp_cleanup_rbuf(msk, 0);
3705 *karg = mptcp_inq_hint(sk);
3706 release_sock(sk);
3707 break;
3708 case SIOCOUTQ:
3709 slow = lock_sock_fast(sk);
3710 *karg = mptcp_ioctl_outq(msk, READ_ONCE(msk->snd_una));
3711 unlock_sock_fast(sk, slow);
3712 break;
3713 case SIOCOUTQNSD:
3714 slow = lock_sock_fast(sk);
3715 *karg = mptcp_ioctl_outq(msk, msk->snd_nxt);
3716 unlock_sock_fast(sk, slow);
3717 break;
3718 default:
3719 return -ENOIOCTLCMD;
3720 }
3721
3722 return 0;
3723 }
3724
mptcp_connect(struct sock * sk,struct sockaddr * uaddr,int addr_len)3725 static int mptcp_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
3726 {
3727 struct mptcp_subflow_context *subflow;
3728 struct mptcp_sock *msk = mptcp_sk(sk);
3729 int err = -EINVAL;
3730 struct sock *ssk;
3731
3732 ssk = __mptcp_nmpc_sk(msk);
3733 if (IS_ERR(ssk))
3734 return PTR_ERR(ssk);
3735
3736 mptcp_set_state(sk, TCP_SYN_SENT);
3737 subflow = mptcp_subflow_ctx(ssk);
3738 #ifdef CONFIG_TCP_MD5SIG
3739 /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
3740 * TCP option space.
3741 */
3742 if (rcu_access_pointer(tcp_sk(ssk)->md5sig_info))
3743 mptcp_early_fallback(msk, subflow, MPTCP_MIB_MD5SIGFALLBACK);
3744 #endif
3745 if (subflow->request_mptcp) {
3746 if (mptcp_active_should_disable(sk))
3747 mptcp_early_fallback(msk, subflow,
3748 MPTCP_MIB_MPCAPABLEACTIVEDISABLED);
3749 else if (mptcp_token_new_connect(ssk) < 0)
3750 mptcp_early_fallback(msk, subflow,
3751 MPTCP_MIB_TOKENFALLBACKINIT);
3752 }
3753
3754 WRITE_ONCE(msk->write_seq, subflow->idsn);
3755 WRITE_ONCE(msk->snd_nxt, subflow->idsn);
3756 WRITE_ONCE(msk->snd_una, subflow->idsn);
3757 if (likely(!__mptcp_check_fallback(msk)))
3758 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVE);
3759
3760 /* if reaching here via the fastopen/sendmsg path, the caller already
3761 * acquired the subflow socket lock, too.
3762 */
3763 if (!msk->fastopening)
3764 lock_sock(ssk);
3765
3766 /* the following mirrors closely a very small chunk of code from
3767 * __inet_stream_connect()
3768 */
3769 if (ssk->sk_state != TCP_CLOSE)
3770 goto out;
3771
3772 if (BPF_CGROUP_PRE_CONNECT_ENABLED(ssk)) {
3773 err = ssk->sk_prot->pre_connect(ssk, uaddr, addr_len);
3774 if (err)
3775 goto out;
3776 }
3777
3778 err = ssk->sk_prot->connect(ssk, uaddr, addr_len);
3779 if (err < 0)
3780 goto out;
3781
3782 inet_assign_bit(DEFER_CONNECT, sk, inet_test_bit(DEFER_CONNECT, ssk));
3783
3784 out:
3785 if (!msk->fastopening)
3786 release_sock(ssk);
3787
3788 /* on successful connect, the msk state will be moved to established by
3789 * subflow_finish_connect()
3790 */
3791 if (unlikely(err)) {
3792 /* avoid leaving a dangling token in an unconnected socket */
3793 mptcp_token_destroy(msk);
3794 mptcp_set_state(sk, TCP_CLOSE);
3795 return err;
3796 }
3797
3798 mptcp_copy_inaddrs(sk, ssk);
3799 return 0;
3800 }
3801
3802 static struct proto mptcp_prot = {
3803 .name = "MPTCP",
3804 .owner = THIS_MODULE,
3805 .init = mptcp_init_sock,
3806 .connect = mptcp_connect,
3807 .disconnect = mptcp_disconnect,
3808 .close = mptcp_close,
3809 .setsockopt = mptcp_setsockopt,
3810 .getsockopt = mptcp_getsockopt,
3811 .shutdown = mptcp_shutdown,
3812 .destroy = mptcp_destroy,
3813 .sendmsg = mptcp_sendmsg,
3814 .ioctl = mptcp_ioctl,
3815 .recvmsg = mptcp_recvmsg,
3816 .release_cb = mptcp_release_cb,
3817 .hash = mptcp_hash,
3818 .unhash = mptcp_unhash,
3819 .get_port = mptcp_get_port,
3820 .stream_memory_free = mptcp_stream_memory_free,
3821 .sockets_allocated = &mptcp_sockets_allocated,
3822
3823 .memory_allocated = &net_aligned_data.tcp_memory_allocated,
3824 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc,
3825
3826 .memory_pressure = &tcp_memory_pressure,
3827 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
3828 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
3829 .sysctl_mem = sysctl_tcp_mem,
3830 .obj_size = sizeof(struct mptcp_sock),
3831 .slab_flags = SLAB_TYPESAFE_BY_RCU,
3832 .no_autobind = true,
3833 };
3834
mptcp_bind(struct socket * sock,struct sockaddr * uaddr,int addr_len)3835 static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
3836 {
3837 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3838 struct sock *ssk, *sk = sock->sk;
3839 int err = -EINVAL;
3840
3841 lock_sock(sk);
3842 ssk = __mptcp_nmpc_sk(msk);
3843 if (IS_ERR(ssk)) {
3844 err = PTR_ERR(ssk);
3845 goto unlock;
3846 }
3847
3848 if (sk->sk_family == AF_INET)
3849 err = inet_bind_sk(ssk, uaddr, addr_len);
3850 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
3851 else if (sk->sk_family == AF_INET6)
3852 err = inet6_bind_sk(ssk, uaddr, addr_len);
3853 #endif
3854 if (!err)
3855 mptcp_copy_inaddrs(sk, ssk);
3856
3857 unlock:
3858 release_sock(sk);
3859 return err;
3860 }
3861
mptcp_listen(struct socket * sock,int backlog)3862 static int mptcp_listen(struct socket *sock, int backlog)
3863 {
3864 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3865 struct sock *sk = sock->sk;
3866 struct sock *ssk;
3867 int err;
3868
3869 pr_debug("msk=%p\n", msk);
3870
3871 lock_sock(sk);
3872
3873 err = -EINVAL;
3874 if (sock->state != SS_UNCONNECTED || sock->type != SOCK_STREAM)
3875 goto unlock;
3876
3877 ssk = __mptcp_nmpc_sk(msk);
3878 if (IS_ERR(ssk)) {
3879 err = PTR_ERR(ssk);
3880 goto unlock;
3881 }
3882
3883 mptcp_set_state(sk, TCP_LISTEN);
3884 sock_set_flag(sk, SOCK_RCU_FREE);
3885
3886 lock_sock(ssk);
3887 err = __inet_listen_sk(ssk, backlog);
3888 release_sock(ssk);
3889 mptcp_set_state(sk, inet_sk_state_load(ssk));
3890
3891 if (!err) {
3892 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
3893 mptcp_copy_inaddrs(sk, ssk);
3894 mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CREATED);
3895 }
3896
3897 unlock:
3898 release_sock(sk);
3899 return err;
3900 }
3901
mptcp_stream_accept(struct socket * sock,struct socket * newsock,struct proto_accept_arg * arg)3902 static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
3903 struct proto_accept_arg *arg)
3904 {
3905 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3906 struct sock *ssk, *newsk;
3907
3908 pr_debug("msk=%p\n", msk);
3909
3910 /* Buggy applications can call accept on socket states other then LISTEN
3911 * but no need to allocate the first subflow just to error out.
3912 */
3913 ssk = READ_ONCE(msk->first);
3914 if (!ssk)
3915 return -EINVAL;
3916
3917 pr_debug("ssk=%p, listener=%p\n", ssk, mptcp_subflow_ctx(ssk));
3918 newsk = inet_csk_accept(ssk, arg);
3919 if (!newsk)
3920 return arg->err;
3921
3922 pr_debug("newsk=%p, subflow is mptcp=%d\n", newsk, sk_is_mptcp(newsk));
3923 if (sk_is_mptcp(newsk)) {
3924 struct mptcp_subflow_context *subflow;
3925 struct sock *new_mptcp_sock;
3926
3927 subflow = mptcp_subflow_ctx(newsk);
3928 new_mptcp_sock = subflow->conn;
3929
3930 /* is_mptcp should be false if subflow->conn is missing, see
3931 * subflow_syn_recv_sock()
3932 */
3933 if (WARN_ON_ONCE(!new_mptcp_sock)) {
3934 tcp_sk(newsk)->is_mptcp = 0;
3935 goto tcpfallback;
3936 }
3937
3938 newsk = new_mptcp_sock;
3939 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_MPCAPABLEPASSIVEACK);
3940
3941 newsk->sk_kern_sock = arg->kern;
3942 lock_sock(newsk);
3943 __inet_accept(sock, newsock, newsk);
3944
3945 set_bit(SOCK_CUSTOM_SOCKOPT, &newsock->flags);
3946 msk = mptcp_sk(newsk);
3947 msk->in_accept_queue = 0;
3948
3949 /* set ssk->sk_socket of accept()ed flows to mptcp socket.
3950 * This is needed so NOSPACE flag can be set from tcp stack.
3951 */
3952 mptcp_for_each_subflow(msk, subflow) {
3953 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3954
3955 if (!ssk->sk_socket)
3956 mptcp_sock_graft(ssk, newsock);
3957 }
3958
3959 mptcp_rps_record_subflows(msk);
3960
3961 /* Do late cleanup for the first subflow as necessary. Also
3962 * deal with bad peers not doing a complete shutdown.
3963 */
3964 if (unlikely(inet_sk_state_load(msk->first) == TCP_CLOSE)) {
3965 __mptcp_close_ssk(newsk, msk->first,
3966 mptcp_subflow_ctx(msk->first), 0);
3967 if (unlikely(list_is_singular(&msk->conn_list)))
3968 mptcp_set_state(newsk, TCP_CLOSE);
3969 }
3970 } else {
3971 tcpfallback:
3972 newsk->sk_kern_sock = arg->kern;
3973 lock_sock(newsk);
3974 __inet_accept(sock, newsock, newsk);
3975 /* we are being invoked after accepting a non-mp-capable
3976 * flow: sk is a tcp_sk, not an mptcp one.
3977 *
3978 * Hand the socket over to tcp so all further socket ops
3979 * bypass mptcp.
3980 */
3981 WRITE_ONCE(newsock->sk->sk_socket->ops,
3982 mptcp_fallback_tcp_ops(newsock->sk));
3983 }
3984 release_sock(newsk);
3985
3986 return 0;
3987 }
3988
mptcp_check_writeable(struct mptcp_sock * msk)3989 static __poll_t mptcp_check_writeable(struct mptcp_sock *msk)
3990 {
3991 struct sock *sk = (struct sock *)msk;
3992
3993 if (__mptcp_stream_is_writeable(sk, 1))
3994 return EPOLLOUT | EPOLLWRNORM;
3995
3996 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
3997 smp_mb__after_atomic(); /* NOSPACE is changed by mptcp_write_space() */
3998 if (__mptcp_stream_is_writeable(sk, 1))
3999 return EPOLLOUT | EPOLLWRNORM;
4000
4001 return 0;
4002 }
4003
mptcp_poll(struct file * file,struct socket * sock,struct poll_table_struct * wait)4004 static __poll_t mptcp_poll(struct file *file, struct socket *sock,
4005 struct poll_table_struct *wait)
4006 {
4007 struct sock *sk = sock->sk;
4008 struct mptcp_sock *msk;
4009 __poll_t mask = 0;
4010 u8 shutdown;
4011 int state;
4012
4013 msk = mptcp_sk(sk);
4014 sock_poll_wait(file, sock, wait);
4015
4016 state = inet_sk_state_load(sk);
4017 pr_debug("msk=%p state=%d flags=%lx\n", msk, state, msk->flags);
4018 if (state == TCP_LISTEN) {
4019 struct sock *ssk = READ_ONCE(msk->first);
4020
4021 if (WARN_ON_ONCE(!ssk))
4022 return 0;
4023
4024 return inet_csk_listen_poll(ssk);
4025 }
4026
4027 shutdown = READ_ONCE(sk->sk_shutdown);
4028 if (shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
4029 mask |= EPOLLHUP;
4030 if (shutdown & RCV_SHUTDOWN)
4031 mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
4032
4033 if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) {
4034 mask |= mptcp_check_readable(sk);
4035 if (shutdown & SEND_SHUTDOWN)
4036 mask |= EPOLLOUT | EPOLLWRNORM;
4037 else
4038 mask |= mptcp_check_writeable(msk);
4039 } else if (state == TCP_SYN_SENT &&
4040 inet_test_bit(DEFER_CONNECT, sk)) {
4041 /* cf tcp_poll() note about TFO */
4042 mask |= EPOLLOUT | EPOLLWRNORM;
4043 }
4044
4045 /* This barrier is coupled with smp_wmb() in __mptcp_error_report() */
4046 smp_rmb();
4047 if (READ_ONCE(sk->sk_err))
4048 mask |= EPOLLERR;
4049
4050 return mask;
4051 }
4052
4053 static const struct proto_ops mptcp_stream_ops = {
4054 .family = PF_INET,
4055 .owner = THIS_MODULE,
4056 .release = inet_release,
4057 .bind = mptcp_bind,
4058 .connect = inet_stream_connect,
4059 .socketpair = sock_no_socketpair,
4060 .accept = mptcp_stream_accept,
4061 .getname = inet_getname,
4062 .poll = mptcp_poll,
4063 .ioctl = inet_ioctl,
4064 .gettstamp = sock_gettstamp,
4065 .listen = mptcp_listen,
4066 .shutdown = inet_shutdown,
4067 .setsockopt = sock_common_setsockopt,
4068 .getsockopt = sock_common_getsockopt,
4069 .sendmsg = inet_sendmsg,
4070 .recvmsg = inet_recvmsg,
4071 .mmap = sock_no_mmap,
4072 .set_rcvlowat = mptcp_set_rcvlowat,
4073 };
4074
4075 static struct inet_protosw mptcp_protosw = {
4076 .type = SOCK_STREAM,
4077 .protocol = IPPROTO_MPTCP,
4078 .prot = &mptcp_prot,
4079 .ops = &mptcp_stream_ops,
4080 .flags = INET_PROTOSW_ICSK,
4081 };
4082
mptcp_napi_poll(struct napi_struct * napi,int budget)4083 static int mptcp_napi_poll(struct napi_struct *napi, int budget)
4084 {
4085 struct mptcp_delegated_action *delegated;
4086 struct mptcp_subflow_context *subflow;
4087 int work_done = 0;
4088
4089 delegated = container_of(napi, struct mptcp_delegated_action, napi);
4090 while ((subflow = mptcp_subflow_delegated_next(delegated)) != NULL) {
4091 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
4092
4093 bh_lock_sock_nested(ssk);
4094 if (!sock_owned_by_user(ssk)) {
4095 mptcp_subflow_process_delegated(ssk, xchg(&subflow->delegated_status, 0));
4096 } else {
4097 /* tcp_release_cb_override already processed
4098 * the action or will do at next release_sock().
4099 * In both case must dequeue the subflow here - on the same
4100 * CPU that scheduled it.
4101 */
4102 smp_wmb();
4103 clear_bit(MPTCP_DELEGATE_SCHEDULED, &subflow->delegated_status);
4104 }
4105 bh_unlock_sock(ssk);
4106 sock_put(ssk);
4107
4108 if (++work_done == budget)
4109 return budget;
4110 }
4111
4112 /* always provide a 0 'work_done' argument, so that napi_complete_done
4113 * will not try accessing the NULL napi->dev ptr
4114 */
4115 napi_complete_done(napi, 0);
4116 return work_done;
4117 }
4118
mptcp_proto_init(void)4119 void __init mptcp_proto_init(void)
4120 {
4121 struct mptcp_delegated_action *delegated;
4122 int cpu;
4123
4124 mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo;
4125
4126 if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL))
4127 panic("Failed to allocate MPTCP pcpu counter\n");
4128
4129 mptcp_napi_dev = alloc_netdev_dummy(0);
4130 if (!mptcp_napi_dev)
4131 panic("Failed to allocate MPTCP dummy netdev\n");
4132 for_each_possible_cpu(cpu) {
4133 delegated = per_cpu_ptr(&mptcp_delegated_actions, cpu);
4134 INIT_LIST_HEAD(&delegated->head);
4135 netif_napi_add_tx(mptcp_napi_dev, &delegated->napi,
4136 mptcp_napi_poll);
4137 napi_enable(&delegated->napi);
4138 }
4139
4140 mptcp_subflow_init();
4141 mptcp_pm_init();
4142 mptcp_sched_init();
4143 mptcp_token_init();
4144
4145 if (proto_register(&mptcp_prot, 1) != 0)
4146 panic("Failed to register MPTCP proto.\n");
4147
4148 inet_register_protosw(&mptcp_protosw);
4149
4150 BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb));
4151 }
4152
4153 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
4154 static const struct proto_ops mptcp_v6_stream_ops = {
4155 .family = PF_INET6,
4156 .owner = THIS_MODULE,
4157 .release = inet6_release,
4158 .bind = mptcp_bind,
4159 .connect = inet_stream_connect,
4160 .socketpair = sock_no_socketpair,
4161 .accept = mptcp_stream_accept,
4162 .getname = inet6_getname,
4163 .poll = mptcp_poll,
4164 .ioctl = inet6_ioctl,
4165 .gettstamp = sock_gettstamp,
4166 .listen = mptcp_listen,
4167 .shutdown = inet_shutdown,
4168 .setsockopt = sock_common_setsockopt,
4169 .getsockopt = sock_common_getsockopt,
4170 .sendmsg = inet6_sendmsg,
4171 .recvmsg = inet6_recvmsg,
4172 .mmap = sock_no_mmap,
4173 #ifdef CONFIG_COMPAT
4174 .compat_ioctl = inet6_compat_ioctl,
4175 #endif
4176 .set_rcvlowat = mptcp_set_rcvlowat,
4177 };
4178
4179 static struct proto mptcp_v6_prot;
4180
4181 static struct inet_protosw mptcp_v6_protosw = {
4182 .type = SOCK_STREAM,
4183 .protocol = IPPROTO_MPTCP,
4184 .prot = &mptcp_v6_prot,
4185 .ops = &mptcp_v6_stream_ops,
4186 .flags = INET_PROTOSW_ICSK,
4187 };
4188
mptcp_proto_v6_init(void)4189 int __init mptcp_proto_v6_init(void)
4190 {
4191 int err;
4192
4193 mptcp_v6_prot = mptcp_prot;
4194 strscpy(mptcp_v6_prot.name, "MPTCPv6", sizeof(mptcp_v6_prot.name));
4195 mptcp_v6_prot.slab = NULL;
4196 mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock);
4197 mptcp_v6_prot.ipv6_pinfo_offset = offsetof(struct mptcp6_sock, np);
4198
4199 err = proto_register(&mptcp_v6_prot, 1);
4200 if (err)
4201 return err;
4202
4203 err = inet6_register_protosw(&mptcp_v6_protosw);
4204 if (err)
4205 proto_unregister(&mptcp_v6_prot);
4206
4207 return err;
4208 }
4209 #endif
4210