1 // SPDX-License-Identifier: GPL-2.0
4 * Copyright (c) 2017 - 2019, Intel Corporation.
7 #define pr_fmt(fmt) "MPTCP: " fmt
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 <linux/igmp.h>
16 #include <net/inet_common.h>
17 #include <net/inet_hashtables.h>
18 #include <net/protocol.h>
20 #include <net/tcp_states.h>
21 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
22 #include <net/transp_v6.h>
23 #include <net/addrconf.h>
25 #include <net/mptcp.h>
30 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
32 struct mptcp_sock msk;
43 #define MPTCP_SKB_CB(__skb) ((struct mptcp_skb_cb *)&((__skb)->cb[0]))
45 static struct percpu_counter mptcp_sockets_allocated;
47 static void __mptcp_destroy_sock(struct sock *sk);
48 static void __mptcp_check_send_data_fin(struct sock *sk);
50 DEFINE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
51 static struct net_device mptcp_napi_dev;
53 /* If msk has an initial subflow socket, and the MP_CAPABLE handshake has not
54 * completed yet or has failed, return the subflow socket.
55 * Otherwise return NULL.
57 struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk)
59 if (!msk->subflow || READ_ONCE(msk->can_ack))
65 /* Returns end sequence number of the receiver's advertised window */
66 static u64 mptcp_wnd_end(const struct mptcp_sock *msk)
68 return READ_ONCE(msk->wnd_end);
71 static bool mptcp_is_tcpsk(struct sock *sk)
73 struct socket *sock = sk->sk_socket;
75 if (unlikely(sk->sk_prot == &tcp_prot)) {
76 /* we are being invoked after mptcp_accept() has
77 * accepted a non-mp-capable flow: sk is a tcp_sk,
80 * Hand the socket over to tcp so all further socket ops
83 sock->ops = &inet_stream_ops;
85 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
86 } else if (unlikely(sk->sk_prot == &tcpv6_prot)) {
87 sock->ops = &inet6_stream_ops;
95 static struct sock *__mptcp_tcp_fallback(struct mptcp_sock *msk)
97 sock_owned_by_me((const struct sock *)msk);
99 if (likely(!__mptcp_check_fallback(msk)))
105 static int __mptcp_socket_create(struct mptcp_sock *msk)
107 struct mptcp_subflow_context *subflow;
108 struct sock *sk = (struct sock *)msk;
109 struct socket *ssock;
112 err = mptcp_subflow_create_socket(sk, &ssock);
116 msk->first = ssock->sk;
117 msk->subflow = ssock;
118 subflow = mptcp_subflow_ctx(ssock->sk);
119 list_add(&subflow->node, &msk->conn_list);
120 sock_hold(ssock->sk);
121 subflow->request_mptcp = 1;
122 mptcp_sock_graft(msk->first, sk->sk_socket);
127 static void mptcp_drop(struct sock *sk, struct sk_buff *skb)
129 sk_drops_add(sk, skb);
133 static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to,
134 struct sk_buff *from)
139 if (MPTCP_SKB_CB(from)->offset ||
140 !skb_try_coalesce(to, from, &fragstolen, &delta))
143 pr_debug("colesced seq %llx into %llx new len %d new end seq %llx",
144 MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq,
145 to->len, MPTCP_SKB_CB(from)->end_seq);
146 MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq;
147 kfree_skb_partial(from, fragstolen);
148 atomic_add(delta, &sk->sk_rmem_alloc);
149 sk_mem_charge(sk, delta);
153 static bool mptcp_ooo_try_coalesce(struct mptcp_sock *msk, struct sk_buff *to,
154 struct sk_buff *from)
156 if (MPTCP_SKB_CB(from)->map_seq != MPTCP_SKB_CB(to)->end_seq)
159 return mptcp_try_coalesce((struct sock *)msk, to, from);
162 /* "inspired" by tcp_data_queue_ofo(), main differences:
164 * - don't cope with sacks
166 static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb)
168 struct sock *sk = (struct sock *)msk;
169 struct rb_node **p, *parent;
170 u64 seq, end_seq, max_seq;
171 struct sk_buff *skb1;
173 seq = MPTCP_SKB_CB(skb)->map_seq;
174 end_seq = MPTCP_SKB_CB(skb)->end_seq;
175 max_seq = READ_ONCE(msk->rcv_wnd_sent);
177 pr_debug("msk=%p seq=%llx limit=%llx empty=%d", msk, seq, max_seq,
178 RB_EMPTY_ROOT(&msk->out_of_order_queue));
179 if (after64(end_seq, max_seq)) {
182 pr_debug("oow by %lld, rcv_wnd_sent %llu\n",
183 (unsigned long long)end_seq - (unsigned long)max_seq,
184 (unsigned long long)msk->rcv_wnd_sent);
185 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_NODSSWINDOW);
189 p = &msk->out_of_order_queue.rb_node;
190 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUE);
191 if (RB_EMPTY_ROOT(&msk->out_of_order_queue)) {
192 rb_link_node(&skb->rbnode, NULL, p);
193 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
194 msk->ooo_last_skb = skb;
198 /* with 2 subflows, adding at end of ooo queue is quite likely
199 * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup.
201 if (mptcp_ooo_try_coalesce(msk, msk->ooo_last_skb, skb)) {
202 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
203 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
207 /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */
208 if (!before64(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) {
209 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
210 parent = &msk->ooo_last_skb->rbnode;
211 p = &parent->rb_right;
215 /* Find place to insert this segment. Handle overlaps on the way. */
219 skb1 = rb_to_skb(parent);
220 if (before64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
221 p = &parent->rb_left;
224 if (before64(seq, MPTCP_SKB_CB(skb1)->end_seq)) {
225 if (!after64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) {
226 /* All the bits are present. Drop. */
228 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
231 if (after64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
235 * continue traversing
238 /* skb's seq == skb1's seq and skb covers skb1.
239 * Replace skb1 with skb.
241 rb_replace_node(&skb1->rbnode, &skb->rbnode,
242 &msk->out_of_order_queue);
243 mptcp_drop(sk, skb1);
244 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
247 } else if (mptcp_ooo_try_coalesce(msk, skb1, skb)) {
248 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
251 p = &parent->rb_right;
255 /* Insert segment into RB tree. */
256 rb_link_node(&skb->rbnode, parent, p);
257 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
260 /* Remove other segments covered by skb. */
261 while ((skb1 = skb_rb_next(skb)) != NULL) {
262 if (before64(end_seq, MPTCP_SKB_CB(skb1)->end_seq))
264 rb_erase(&skb1->rbnode, &msk->out_of_order_queue);
265 mptcp_drop(sk, skb1);
266 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
268 /* If there is no skb after us, we are the last_skb ! */
270 msk->ooo_last_skb = skb;
274 skb_set_owner_r(skb, sk);
277 static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk,
278 struct sk_buff *skb, unsigned int offset,
281 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
282 struct sock *sk = (struct sock *)msk;
283 struct sk_buff *tail;
285 __skb_unlink(skb, &ssk->sk_receive_queue);
290 /* try to fetch required memory from subflow */
291 if (!sk_rmem_schedule(sk, skb, skb->truesize)) {
292 if (ssk->sk_forward_alloc < skb->truesize)
294 __sk_mem_reclaim(ssk, skb->truesize);
295 if (!sk_rmem_schedule(sk, skb, skb->truesize))
299 /* the skb map_seq accounts for the skb offset:
300 * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq
303 MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow);
304 MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len;
305 MPTCP_SKB_CB(skb)->offset = offset;
307 if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) {
309 WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len);
310 tail = skb_peek_tail(&sk->sk_receive_queue);
311 if (tail && mptcp_try_coalesce(sk, tail, skb))
314 skb_set_owner_r(skb, sk);
315 __skb_queue_tail(&sk->sk_receive_queue, skb);
317 } else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) {
318 mptcp_data_queue_ofo(msk, skb);
322 /* old data, keep it simple and drop the whole pkt, sender
323 * will retransmit as needed, if needed.
325 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
331 static void mptcp_stop_timer(struct sock *sk)
333 struct inet_connection_sock *icsk = inet_csk(sk);
335 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
336 mptcp_sk(sk)->timer_ival = 0;
339 static void mptcp_close_wake_up(struct sock *sk)
341 if (sock_flag(sk, SOCK_DEAD))
344 sk->sk_state_change(sk);
345 if (sk->sk_shutdown == SHUTDOWN_MASK ||
346 sk->sk_state == TCP_CLOSE)
347 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
349 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
352 static bool mptcp_pending_data_fin_ack(struct sock *sk)
354 struct mptcp_sock *msk = mptcp_sk(sk);
356 return !__mptcp_check_fallback(msk) &&
357 ((1 << sk->sk_state) &
358 (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) &&
359 msk->write_seq == READ_ONCE(msk->snd_una);
362 static void mptcp_check_data_fin_ack(struct sock *sk)
364 struct mptcp_sock *msk = mptcp_sk(sk);
366 /* Look for an acknowledged DATA_FIN */
367 if (mptcp_pending_data_fin_ack(sk)) {
368 WRITE_ONCE(msk->snd_data_fin_enable, 0);
370 switch (sk->sk_state) {
372 inet_sk_state_store(sk, TCP_FIN_WAIT2);
376 inet_sk_state_store(sk, TCP_CLOSE);
380 mptcp_close_wake_up(sk);
384 static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq)
386 struct mptcp_sock *msk = mptcp_sk(sk);
388 if (READ_ONCE(msk->rcv_data_fin) &&
389 ((1 << sk->sk_state) &
390 (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) {
391 u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq);
393 if (msk->ack_seq == rcv_data_fin_seq) {
395 *seq = rcv_data_fin_seq;
404 static void mptcp_set_timeout(const struct sock *sk, const struct sock *ssk)
406 long tout = ssk && inet_csk(ssk)->icsk_pending ?
407 inet_csk(ssk)->icsk_timeout - jiffies : 0;
410 tout = mptcp_sk(sk)->timer_ival;
411 mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
414 static bool mptcp_subflow_active(struct mptcp_subflow_context *subflow)
416 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
418 /* can't send if JOIN hasn't completed yet (i.e. is usable for mptcp) */
419 if (subflow->request_join && !subflow->fully_established)
422 /* only send if our side has not closed yet */
423 return ((1 << ssk->sk_state) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT));
426 static bool tcp_can_send_ack(const struct sock *ssk)
428 return !((1 << inet_sk_state_load(ssk)) &
429 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE | TCPF_LISTEN));
432 static void mptcp_send_ack(struct mptcp_sock *msk)
434 struct mptcp_subflow_context *subflow;
436 mptcp_for_each_subflow(msk, subflow) {
437 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
440 if (tcp_can_send_ack(ssk))
446 static bool mptcp_subflow_cleanup_rbuf(struct sock *ssk)
451 ret = tcp_can_send_ack(ssk);
453 tcp_cleanup_rbuf(ssk, 1);
458 static void mptcp_cleanup_rbuf(struct mptcp_sock *msk)
460 struct sock *ack_hint = READ_ONCE(msk->ack_hint);
461 int old_space = READ_ONCE(msk->old_wspace);
462 struct mptcp_subflow_context *subflow;
463 struct sock *sk = (struct sock *)msk;
466 /* this is a simple superset of what tcp_cleanup_rbuf() implements
467 * so that we don't have to acquire the ssk socket lock most of the time
468 * to do actually nothing
470 cleanup = __mptcp_space(sk) - old_space >= max(0, old_space);
474 /* if the hinted ssk is still active, try to use it */
475 if (likely(ack_hint)) {
476 mptcp_for_each_subflow(msk, subflow) {
477 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
479 if (ack_hint == ssk && mptcp_subflow_cleanup_rbuf(ssk))
484 /* otherwise pick the first active subflow */
485 mptcp_for_each_subflow(msk, subflow)
486 if (mptcp_subflow_cleanup_rbuf(mptcp_subflow_tcp_sock(subflow)))
490 static bool mptcp_check_data_fin(struct sock *sk)
492 struct mptcp_sock *msk = mptcp_sk(sk);
493 u64 rcv_data_fin_seq;
496 if (__mptcp_check_fallback(msk) || !msk->first)
499 /* Need to ack a DATA_FIN received from a peer while this side
500 * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2.
501 * msk->rcv_data_fin was set when parsing the incoming options
502 * at the subflow level and the msk lock was not held, so this
503 * is the first opportunity to act on the DATA_FIN and change
506 * If we are caught up to the sequence number of the incoming
507 * DATA_FIN, send the DATA_ACK now and do state transition. If
508 * not caught up, do nothing and let the recv code send DATA_ACK
512 if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) {
513 WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1);
514 WRITE_ONCE(msk->rcv_data_fin, 0);
516 sk->sk_shutdown |= RCV_SHUTDOWN;
517 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
518 set_bit(MPTCP_DATA_READY, &msk->flags);
520 switch (sk->sk_state) {
521 case TCP_ESTABLISHED:
522 inet_sk_state_store(sk, TCP_CLOSE_WAIT);
525 inet_sk_state_store(sk, TCP_CLOSING);
528 inet_sk_state_store(sk, TCP_CLOSE);
531 /* Other states not expected */
537 mptcp_set_timeout(sk, NULL);
539 mptcp_close_wake_up(sk);
544 static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
548 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
549 struct sock *sk = (struct sock *)msk;
550 unsigned int moved = 0;
551 bool more_data_avail;
556 sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
558 if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
559 int ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
561 if (unlikely(ssk_rbuf > sk_rbuf)) {
562 WRITE_ONCE(sk->sk_rcvbuf, ssk_rbuf);
567 pr_debug("msk=%p ssk=%p", msk, ssk);
570 u32 map_remaining, offset;
571 u32 seq = tp->copied_seq;
575 /* try to move as much data as available */
576 map_remaining = subflow->map_data_len -
577 mptcp_subflow_get_map_offset(subflow);
579 skb = skb_peek(&ssk->sk_receive_queue);
581 /* if no data is found, a racing workqueue/recvmsg
582 * already processed the new data, stop here or we
583 * can enter an infinite loop
590 if (__mptcp_check_fallback(msk)) {
591 /* if we are running under the workqueue, TCP could have
592 * collapsed skbs between dummy map creation and now
593 * be sure to adjust the size
595 map_remaining = skb->len;
596 subflow->map_data_len = skb->len;
599 offset = seq - TCP_SKB_CB(skb)->seq;
600 fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
606 if (offset < skb->len) {
607 size_t len = skb->len - offset;
612 if (__mptcp_move_skb(msk, ssk, skb, offset, len))
616 if (WARN_ON_ONCE(map_remaining < len))
620 sk_eat_skb(ssk, skb);
624 WRITE_ONCE(tp->copied_seq, seq);
625 more_data_avail = mptcp_subflow_data_available(ssk);
627 if (atomic_read(&sk->sk_rmem_alloc) > sk_rbuf) {
631 } while (more_data_avail);
632 WRITE_ONCE(msk->ack_hint, ssk);
638 static bool __mptcp_ofo_queue(struct mptcp_sock *msk)
640 struct sock *sk = (struct sock *)msk;
641 struct sk_buff *skb, *tail;
646 p = rb_first(&msk->out_of_order_queue);
647 pr_debug("msk=%p empty=%d", msk, RB_EMPTY_ROOT(&msk->out_of_order_queue));
650 if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq))
654 rb_erase(&skb->rbnode, &msk->out_of_order_queue);
656 if (unlikely(!after64(MPTCP_SKB_CB(skb)->end_seq,
659 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
663 end_seq = MPTCP_SKB_CB(skb)->end_seq;
664 tail = skb_peek_tail(&sk->sk_receive_queue);
665 if (!tail || !mptcp_ooo_try_coalesce(msk, tail, skb)) {
666 int delta = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq;
668 /* skip overlapping data, if any */
669 pr_debug("uncoalesced seq=%llx ack seq=%llx delta=%d",
670 MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq,
672 MPTCP_SKB_CB(skb)->offset += delta;
673 __skb_queue_tail(&sk->sk_receive_queue, skb);
675 msk->ack_seq = end_seq;
681 /* In most cases we will be able to lock the mptcp socket. If its already
682 * owned, we need to defer to the work queue to avoid ABBA deadlock.
684 static void move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk)
686 struct sock *sk = (struct sock *)msk;
687 unsigned int moved = 0;
689 if (inet_sk_state_load(sk) == TCP_CLOSE)
694 __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
695 __mptcp_ofo_queue(msk);
697 /* If the moves have caught up with the DATA_FIN sequence number
698 * it's time to ack the DATA_FIN and change socket state, but
699 * this is not a good place to change state. Let the workqueue
702 if (mptcp_pending_data_fin(sk, NULL))
703 mptcp_schedule_work(sk);
704 mptcp_data_unlock(sk);
707 void mptcp_data_ready(struct sock *sk, struct sock *ssk)
709 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
710 struct mptcp_sock *msk = mptcp_sk(sk);
711 int sk_rbuf, ssk_rbuf;
714 /* The peer can send data while we are shutting down this
715 * subflow at msk destruction time, but we must avoid enqueuing
716 * more data to the msk receive queue
718 if (unlikely(subflow->disposable))
721 /* move_skbs_to_msk below can legitly clear the data_avail flag,
722 * but we will need later to properly woke the reader, cache its
725 wake = subflow->data_avail == MPTCP_SUBFLOW_DATA_AVAIL;
727 set_bit(MPTCP_DATA_READY, &msk->flags);
729 ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
730 sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
731 if (unlikely(ssk_rbuf > sk_rbuf))
734 /* over limit? can't append more skbs to msk */
735 if (atomic_read(&sk->sk_rmem_alloc) > sk_rbuf)
738 move_skbs_to_msk(msk, ssk);
742 sk->sk_data_ready(sk);
745 void __mptcp_flush_join_list(struct mptcp_sock *msk)
747 struct mptcp_subflow_context *subflow;
749 if (likely(list_empty(&msk->join_list)))
752 spin_lock_bh(&msk->join_list_lock);
753 list_for_each_entry(subflow, &msk->join_list, node)
754 mptcp_propagate_sndbuf((struct sock *)msk, mptcp_subflow_tcp_sock(subflow));
755 list_splice_tail_init(&msk->join_list, &msk->conn_list);
756 spin_unlock_bh(&msk->join_list_lock);
759 static bool mptcp_timer_pending(struct sock *sk)
761 return timer_pending(&inet_csk(sk)->icsk_retransmit_timer);
764 static void mptcp_reset_timer(struct sock *sk)
766 struct inet_connection_sock *icsk = inet_csk(sk);
769 /* prevent rescheduling on close */
770 if (unlikely(inet_sk_state_load(sk) == TCP_CLOSE))
773 /* should never be called with mptcp level timer cleared */
774 tout = READ_ONCE(mptcp_sk(sk)->timer_ival);
775 if (WARN_ON_ONCE(!tout))
777 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout);
780 bool mptcp_schedule_work(struct sock *sk)
782 if (inet_sk_state_load(sk) != TCP_CLOSE &&
783 schedule_work(&mptcp_sk(sk)->work)) {
784 /* each subflow already holds a reference to the sk, and the
785 * workqueue is invoked by a subflow, so sk can't go away here.
793 void mptcp_subflow_eof(struct sock *sk)
795 if (!test_and_set_bit(MPTCP_WORK_EOF, &mptcp_sk(sk)->flags))
796 mptcp_schedule_work(sk);
799 static void mptcp_check_for_eof(struct mptcp_sock *msk)
801 struct mptcp_subflow_context *subflow;
802 struct sock *sk = (struct sock *)msk;
805 mptcp_for_each_subflow(msk, subflow)
806 receivers += !subflow->rx_eof;
810 if (!(sk->sk_shutdown & RCV_SHUTDOWN)) {
811 /* hopefully temporary hack: propagate shutdown status
812 * to msk, when all subflows agree on it
814 sk->sk_shutdown |= RCV_SHUTDOWN;
816 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
817 set_bit(MPTCP_DATA_READY, &msk->flags);
818 sk->sk_data_ready(sk);
821 switch (sk->sk_state) {
822 case TCP_ESTABLISHED:
823 inet_sk_state_store(sk, TCP_CLOSE_WAIT);
826 inet_sk_state_store(sk, TCP_CLOSING);
829 inet_sk_state_store(sk, TCP_CLOSE);
834 mptcp_close_wake_up(sk);
837 static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk)
839 struct mptcp_subflow_context *subflow;
840 struct sock *sk = (struct sock *)msk;
842 sock_owned_by_me(sk);
844 mptcp_for_each_subflow(msk, subflow) {
845 if (subflow->data_avail)
846 return mptcp_subflow_tcp_sock(subflow);
852 static bool mptcp_skb_can_collapse_to(u64 write_seq,
853 const struct sk_buff *skb,
854 const struct mptcp_ext *mpext)
856 if (!tcp_skb_can_collapse_to(skb))
859 /* can collapse only if MPTCP level sequence is in order and this
860 * mapping has not been xmitted yet
862 return mpext && mpext->data_seq + mpext->data_len == write_seq &&
866 static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk,
867 const struct page_frag *pfrag,
868 const struct mptcp_data_frag *df)
870 return df && pfrag->page == df->page &&
871 pfrag->size - pfrag->offset > 0 &&
872 df->data_seq + df->data_len == msk->write_seq;
875 static int mptcp_wmem_with_overhead(struct sock *sk, int size)
877 struct mptcp_sock *msk = mptcp_sk(sk);
880 ret = size + ((sizeof(struct mptcp_data_frag) * size) >> PAGE_SHIFT);
881 skbs = (msk->tx_pending_data + size) / msk->size_goal_cache;
882 if (skbs < msk->skb_tx_cache.qlen)
885 return ret + (skbs - msk->skb_tx_cache.qlen) * SKB_TRUESIZE(MAX_TCP_HEADER);
888 static void __mptcp_wmem_reserve(struct sock *sk, int size)
890 int amount = mptcp_wmem_with_overhead(sk, size);
891 struct mptcp_sock *msk = mptcp_sk(sk);
893 WARN_ON_ONCE(msk->wmem_reserved);
894 if (WARN_ON_ONCE(amount < 0))
897 if (amount <= sk->sk_forward_alloc)
900 /* under memory pressure try to reserve at most a single page
901 * otherwise try to reserve the full estimate and fallback
902 * to a single page before entering the error path
904 if ((tcp_under_memory_pressure(sk) && amount > PAGE_SIZE) ||
905 !sk_wmem_schedule(sk, amount)) {
906 if (amount <= PAGE_SIZE)
910 if (!sk_wmem_schedule(sk, amount))
915 msk->wmem_reserved = amount;
916 sk->sk_forward_alloc -= amount;
920 /* we will wait for memory on next allocation */
921 msk->wmem_reserved = -1;
924 static void __mptcp_update_wmem(struct sock *sk)
926 struct mptcp_sock *msk = mptcp_sk(sk);
928 if (!msk->wmem_reserved)
931 if (msk->wmem_reserved < 0)
932 msk->wmem_reserved = 0;
933 if (msk->wmem_reserved > 0) {
934 sk->sk_forward_alloc += msk->wmem_reserved;
935 msk->wmem_reserved = 0;
939 static bool mptcp_wmem_alloc(struct sock *sk, int size)
941 struct mptcp_sock *msk = mptcp_sk(sk);
943 /* check for pre-existing error condition */
944 if (msk->wmem_reserved < 0)
947 if (msk->wmem_reserved >= size)
951 if (!sk_wmem_schedule(sk, size)) {
952 mptcp_data_unlock(sk);
956 sk->sk_forward_alloc -= size;
957 msk->wmem_reserved += size;
958 mptcp_data_unlock(sk);
961 msk->wmem_reserved -= size;
965 static void mptcp_wmem_uncharge(struct sock *sk, int size)
967 struct mptcp_sock *msk = mptcp_sk(sk);
969 if (msk->wmem_reserved < 0)
970 msk->wmem_reserved = 0;
971 msk->wmem_reserved += size;
974 static void mptcp_mem_reclaim_partial(struct sock *sk)
976 struct mptcp_sock *msk = mptcp_sk(sk);
978 /* if we are experiencing a transint allocation error,
979 * the forward allocation memory has been already
982 if (msk->wmem_reserved < 0)
986 sk->sk_forward_alloc += msk->wmem_reserved;
987 sk_mem_reclaim_partial(sk);
988 msk->wmem_reserved = sk->sk_forward_alloc;
989 sk->sk_forward_alloc = 0;
990 mptcp_data_unlock(sk);
993 static void dfrag_uncharge(struct sock *sk, int len)
995 sk_mem_uncharge(sk, len);
996 sk_wmem_queued_add(sk, -len);
999 static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag)
1001 int len = dfrag->data_len + dfrag->overhead;
1003 list_del(&dfrag->list);
1004 dfrag_uncharge(sk, len);
1005 put_page(dfrag->page);
1008 static void __mptcp_clean_una(struct sock *sk)
1010 struct mptcp_sock *msk = mptcp_sk(sk);
1011 struct mptcp_data_frag *dtmp, *dfrag;
1012 bool cleaned = false;
1015 /* on fallback we just need to ignore snd_una, as this is really
1018 if (__mptcp_check_fallback(msk))
1019 msk->snd_una = READ_ONCE(msk->snd_nxt);
1021 snd_una = msk->snd_una;
1022 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) {
1023 if (after64(dfrag->data_seq + dfrag->data_len, snd_una))
1026 if (WARN_ON_ONCE(dfrag == msk->first_pending))
1028 dfrag_clear(sk, dfrag);
1032 dfrag = mptcp_rtx_head(sk);
1033 if (dfrag && after64(snd_una, dfrag->data_seq)) {
1034 u64 delta = snd_una - dfrag->data_seq;
1036 if (WARN_ON_ONCE(delta > dfrag->already_sent))
1039 dfrag->data_seq += delta;
1040 dfrag->offset += delta;
1041 dfrag->data_len -= delta;
1042 dfrag->already_sent -= delta;
1044 dfrag_uncharge(sk, delta);
1050 if (tcp_under_memory_pressure(sk)) {
1051 __mptcp_update_wmem(sk);
1052 sk_mem_reclaim_partial(sk);
1056 if (snd_una == READ_ONCE(msk->snd_nxt)) {
1057 if (msk->timer_ival)
1058 mptcp_stop_timer(sk);
1060 mptcp_reset_timer(sk);
1064 static void __mptcp_clean_una_wakeup(struct sock *sk)
1066 __mptcp_clean_una(sk);
1067 mptcp_write_space(sk);
1070 static void mptcp_enter_memory_pressure(struct sock *sk)
1072 struct mptcp_subflow_context *subflow;
1073 struct mptcp_sock *msk = mptcp_sk(sk);
1076 sk_stream_moderate_sndbuf(sk);
1077 mptcp_for_each_subflow(msk, subflow) {
1078 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
1081 tcp_enter_memory_pressure(ssk);
1082 sk_stream_moderate_sndbuf(ssk);
1087 /* ensure we get enough memory for the frag hdr, beyond some minimal amount of
1090 static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag)
1092 if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag),
1093 pfrag, sk->sk_allocation)))
1096 mptcp_enter_memory_pressure(sk);
1100 static struct mptcp_data_frag *
1101 mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag,
1104 int offset = ALIGN(orig_offset, sizeof(long));
1105 struct mptcp_data_frag *dfrag;
1107 dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset);
1108 dfrag->data_len = 0;
1109 dfrag->data_seq = msk->write_seq;
1110 dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag);
1111 dfrag->offset = offset + sizeof(struct mptcp_data_frag);
1112 dfrag->already_sent = 0;
1113 dfrag->page = pfrag->page;
1118 struct mptcp_sendmsg_info {
1126 static int mptcp_check_allowed_size(struct mptcp_sock *msk, u64 data_seq,
1129 u64 window_end = mptcp_wnd_end(msk);
1131 if (__mptcp_check_fallback(msk))
1134 if (!before64(data_seq + avail_size, window_end)) {
1135 u64 allowed_size = window_end - data_seq;
1137 return min_t(unsigned int, allowed_size, avail_size);
1143 static bool __mptcp_add_ext(struct sk_buff *skb, gfp_t gfp)
1145 struct skb_ext *mpext = __skb_ext_alloc(gfp);
1149 __skb_ext_set(skb, SKB_EXT_MPTCP, mpext);
1153 static struct sk_buff *__mptcp_do_alloc_tx_skb(struct sock *sk, gfp_t gfp)
1155 struct sk_buff *skb;
1157 skb = alloc_skb_fclone(MAX_TCP_HEADER, gfp);
1159 if (likely(__mptcp_add_ext(skb, gfp))) {
1160 skb_reserve(skb, MAX_TCP_HEADER);
1161 skb->reserved_tailroom = skb->end - skb->tail;
1166 mptcp_enter_memory_pressure(sk);
1171 static bool mptcp_tx_cache_refill(struct sock *sk, int size,
1172 struct sk_buff_head *skbs, int *total_ts)
1174 struct mptcp_sock *msk = mptcp_sk(sk);
1175 struct sk_buff *skb;
1178 if (unlikely(tcp_under_memory_pressure(sk))) {
1179 mptcp_mem_reclaim_partial(sk);
1181 /* under pressure pre-allocate at most a single skb */
1182 if (msk->skb_tx_cache.qlen)
1184 space_needed = msk->size_goal_cache;
1186 space_needed = msk->tx_pending_data + size -
1187 msk->skb_tx_cache.qlen * msk->size_goal_cache;
1190 while (space_needed > 0) {
1191 skb = __mptcp_do_alloc_tx_skb(sk, sk->sk_allocation);
1192 if (unlikely(!skb)) {
1193 /* under memory pressure, try to pass the caller a
1194 * single skb to allow forward progress
1196 while (skbs->qlen > 1) {
1197 skb = __skb_dequeue_tail(skbs);
1198 *total_ts -= skb->truesize;
1201 return skbs->qlen > 0;
1204 *total_ts += skb->truesize;
1205 __skb_queue_tail(skbs, skb);
1206 space_needed -= msk->size_goal_cache;
1211 static bool __mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, gfp_t gfp)
1213 struct mptcp_sock *msk = mptcp_sk(sk);
1214 struct sk_buff *skb;
1216 if (ssk->sk_tx_skb_cache) {
1217 skb = ssk->sk_tx_skb_cache;
1218 if (unlikely(!skb_ext_find(skb, SKB_EXT_MPTCP) &&
1219 !__mptcp_add_ext(skb, gfp)))
1224 skb = skb_peek(&msk->skb_tx_cache);
1226 if (likely(sk_wmem_schedule(ssk, skb->truesize))) {
1227 skb = __skb_dequeue(&msk->skb_tx_cache);
1228 if (WARN_ON_ONCE(!skb))
1231 mptcp_wmem_uncharge(sk, skb->truesize);
1232 ssk->sk_tx_skb_cache = skb;
1236 /* over memory limit, no point to try to allocate a new skb */
1240 skb = __mptcp_do_alloc_tx_skb(sk, gfp);
1244 if (likely(sk_wmem_schedule(ssk, skb->truesize))) {
1245 ssk->sk_tx_skb_cache = skb;
1252 static bool mptcp_must_reclaim_memory(struct sock *sk, struct sock *ssk)
1254 return !ssk->sk_tx_skb_cache &&
1255 !skb_peek(&mptcp_sk(sk)->skb_tx_cache) &&
1256 tcp_under_memory_pressure(sk);
1259 static bool mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk)
1261 if (unlikely(mptcp_must_reclaim_memory(sk, ssk)))
1262 mptcp_mem_reclaim_partial(sk);
1263 return __mptcp_alloc_tx_skb(sk, ssk, sk->sk_allocation);
1266 static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
1267 struct mptcp_data_frag *dfrag,
1268 struct mptcp_sendmsg_info *info)
1270 u64 data_seq = dfrag->data_seq + info->sent;
1271 struct mptcp_sock *msk = mptcp_sk(sk);
1272 bool zero_window_probe = false;
1273 struct mptcp_ext *mpext = NULL;
1274 struct sk_buff *skb, *tail;
1275 bool can_collapse = false;
1280 pr_debug("msk=%p ssk=%p sending dfrag at seq=%lld len=%d already sent=%d",
1281 msk, ssk, dfrag->data_seq, dfrag->data_len, info->sent);
1283 /* compute send limit */
1284 info->mss_now = tcp_send_mss(ssk, &info->size_goal, info->flags);
1285 avail_size = info->size_goal;
1286 msk->size_goal_cache = info->size_goal;
1287 skb = tcp_write_queue_tail(ssk);
1289 /* Limit the write to the size available in the
1290 * current skb, if any, so that we create at most a new skb.
1291 * Explicitly tells TCP internals to avoid collapsing on later
1292 * queue management operation, to avoid breaking the ext <->
1293 * SSN association set here
1295 mpext = skb_ext_find(skb, SKB_EXT_MPTCP);
1296 can_collapse = (info->size_goal - skb->len > 0) &&
1297 mptcp_skb_can_collapse_to(data_seq, skb, mpext);
1298 if (!can_collapse) {
1299 TCP_SKB_CB(skb)->eor = 1;
1301 size_bias = skb->len;
1302 avail_size = info->size_goal - skb->len;
1306 /* Zero window and all data acked? Probe. */
1307 avail_size = mptcp_check_allowed_size(msk, data_seq, avail_size);
1308 if (avail_size == 0) {
1309 u64 snd_una = READ_ONCE(msk->snd_una);
1311 if (skb || snd_una != msk->snd_nxt)
1313 zero_window_probe = true;
1314 data_seq = snd_una - 1;
1318 if (WARN_ON_ONCE(info->sent > info->limit ||
1319 info->limit > dfrag->data_len))
1322 ret = info->limit - info->sent;
1323 tail = tcp_build_frag(ssk, avail_size + size_bias, info->flags,
1324 dfrag->page, dfrag->offset + info->sent, &ret);
1326 tcp_remove_empty_skb(sk, tcp_write_queue_tail(ssk));
1330 /* if the tail skb is still the cached one, collapsing really happened.
1333 TCP_SKB_CB(tail)->tcp_flags &= ~TCPHDR_PSH;
1334 mpext->data_len += ret;
1335 WARN_ON_ONCE(!can_collapse);
1336 WARN_ON_ONCE(zero_window_probe);
1340 mpext = skb_ext_find(tail, SKB_EXT_MPTCP);
1341 if (WARN_ON_ONCE(!mpext)) {
1342 /* should never reach here, stream corrupted */
1346 memset(mpext, 0, sizeof(*mpext));
1347 mpext->data_seq = data_seq;
1348 mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq;
1349 mpext->data_len = ret;
1353 pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d",
1354 mpext->data_seq, mpext->subflow_seq, mpext->data_len,
1357 if (zero_window_probe) {
1358 mptcp_subflow_ctx(ssk)->rel_write_seq += ret;
1361 tcp_push_pending_frames(ssk);
1364 mptcp_subflow_ctx(ssk)->rel_write_seq += ret;
1368 #define MPTCP_SEND_BURST_SIZE ((1 << 16) - \
1369 sizeof(struct tcphdr) - \
1370 MAX_TCP_OPTION_SPACE - \
1371 sizeof(struct ipv6hdr) - \
1372 sizeof(struct frag_hdr))
1374 struct subflow_send_info {
1379 static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk)
1381 struct subflow_send_info send_info[2];
1382 struct mptcp_subflow_context *subflow;
1383 int i, nr_active = 0;
1388 sock_owned_by_me((struct sock *)msk);
1390 if (__mptcp_check_fallback(msk)) {
1393 return sk_stream_memory_free(msk->first) ? msk->first : NULL;
1396 /* re-use last subflow, if the burst allow that */
1397 if (msk->last_snd && msk->snd_burst > 0 &&
1398 sk_stream_memory_free(msk->last_snd) &&
1399 mptcp_subflow_active(mptcp_subflow_ctx(msk->last_snd)))
1400 return msk->last_snd;
1402 /* pick the subflow with the lower wmem/wspace ratio */
1403 for (i = 0; i < 2; ++i) {
1404 send_info[i].ssk = NULL;
1405 send_info[i].ratio = -1;
1407 mptcp_for_each_subflow(msk, subflow) {
1408 ssk = mptcp_subflow_tcp_sock(subflow);
1409 if (!mptcp_subflow_active(subflow))
1412 nr_active += !subflow->backup;
1413 if (!sk_stream_memory_free(subflow->tcp_sock) || !tcp_sk(ssk)->snd_wnd)
1416 pace = READ_ONCE(ssk->sk_pacing_rate);
1420 ratio = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32,
1422 if (ratio < send_info[subflow->backup].ratio) {
1423 send_info[subflow->backup].ssk = ssk;
1424 send_info[subflow->backup].ratio = ratio;
1428 pr_debug("msk=%p nr_active=%d ssk=%p:%lld backup=%p:%lld",
1429 msk, nr_active, send_info[0].ssk, send_info[0].ratio,
1430 send_info[1].ssk, send_info[1].ratio);
1432 /* pick the best backup if no other subflow is active */
1434 send_info[0].ssk = send_info[1].ssk;
1436 if (send_info[0].ssk) {
1437 msk->last_snd = send_info[0].ssk;
1438 msk->snd_burst = min_t(int, MPTCP_SEND_BURST_SIZE,
1439 tcp_sk(msk->last_snd)->snd_wnd);
1440 return msk->last_snd;
1446 static void mptcp_push_release(struct sock *sk, struct sock *ssk,
1447 struct mptcp_sendmsg_info *info)
1449 mptcp_set_timeout(sk, ssk);
1450 tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal);
1454 static void __mptcp_push_pending(struct sock *sk, unsigned int flags)
1456 struct sock *prev_ssk = NULL, *ssk = NULL;
1457 struct mptcp_sock *msk = mptcp_sk(sk);
1458 struct mptcp_sendmsg_info info = {
1461 struct mptcp_data_frag *dfrag;
1462 int len, copied = 0;
1464 while ((dfrag = mptcp_send_head(sk))) {
1465 info.sent = dfrag->already_sent;
1466 info.limit = dfrag->data_len;
1467 len = dfrag->data_len - dfrag->already_sent;
1472 __mptcp_flush_join_list(msk);
1473 ssk = mptcp_subflow_get_send(msk);
1475 /* try to keep the subflow socket lock across
1476 * consecutive xmit on the same socket
1478 if (ssk != prev_ssk && prev_ssk)
1479 mptcp_push_release(sk, prev_ssk, &info);
1483 if (ssk != prev_ssk || !prev_ssk)
1486 /* keep it simple and always provide a new skb for the
1487 * subflow, even if we will not use it when collapsing
1488 * on the pending one
1490 if (!mptcp_alloc_tx_skb(sk, ssk)) {
1491 mptcp_push_release(sk, ssk, &info);
1495 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
1497 mptcp_push_release(sk, ssk, &info);
1502 dfrag->already_sent += ret;
1503 msk->snd_nxt += ret;
1504 msk->snd_burst -= ret;
1505 msk->tx_pending_data -= ret;
1509 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1512 /* at this point we held the socket lock for the last subflow we used */
1514 mptcp_push_release(sk, ssk, &info);
1518 /* start the timer, if it's not pending */
1519 if (!mptcp_timer_pending(sk))
1520 mptcp_reset_timer(sk);
1521 __mptcp_check_send_data_fin(sk);
1525 static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk)
1527 struct mptcp_sock *msk = mptcp_sk(sk);
1528 struct mptcp_sendmsg_info info;
1529 struct mptcp_data_frag *dfrag;
1530 struct sock *xmit_ssk;
1531 int len, copied = 0;
1535 while ((dfrag = mptcp_send_head(sk))) {
1536 info.sent = dfrag->already_sent;
1537 info.limit = dfrag->data_len;
1538 len = dfrag->data_len - dfrag->already_sent;
1542 /* the caller already invoked the packet scheduler,
1543 * check for a different subflow usage only after
1544 * spooling the first chunk of data
1546 xmit_ssk = first ? ssk : mptcp_subflow_get_send(mptcp_sk(sk));
1549 if (xmit_ssk != ssk) {
1550 mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk));
1554 if (unlikely(mptcp_must_reclaim_memory(sk, ssk))) {
1555 __mptcp_update_wmem(sk);
1556 sk_mem_reclaim_partial(sk);
1558 if (!__mptcp_alloc_tx_skb(sk, ssk, GFP_ATOMIC))
1561 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
1566 dfrag->already_sent += ret;
1567 msk->snd_nxt += ret;
1568 msk->snd_burst -= ret;
1569 msk->tx_pending_data -= ret;
1574 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1578 /* __mptcp_alloc_tx_skb could have released some wmem and we are
1579 * not going to flush it via release_sock()
1581 __mptcp_update_wmem(sk);
1583 mptcp_set_timeout(sk, ssk);
1584 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
1586 if (!mptcp_timer_pending(sk))
1587 mptcp_reset_timer(sk);
1589 if (msk->snd_data_fin_enable &&
1590 msk->snd_nxt + 1 == msk->write_seq)
1591 mptcp_schedule_work(sk);
1595 static void mptcp_set_nospace(struct sock *sk)
1597 /* enable autotune */
1598 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1600 /* will be cleared on avail space */
1601 set_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags);
1604 static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
1606 struct mptcp_sock *msk = mptcp_sk(sk);
1607 struct page_frag *pfrag;
1612 if (msg->msg_flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL))
1615 mptcp_lock_sock(sk, __mptcp_wmem_reserve(sk, min_t(size_t, 1 << 20, len)));
1617 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1619 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
1620 ret = sk_stream_wait_connect(sk, &timeo);
1625 pfrag = sk_page_frag(sk);
1627 while (msg_data_left(msg)) {
1628 int total_ts, frag_truesize = 0;
1629 struct mptcp_data_frag *dfrag;
1630 struct sk_buff_head skbs;
1631 bool dfrag_collapsed;
1632 size_t psize, offset;
1634 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) {
1639 /* reuse tail pfrag, if possible, or carve a new one from the
1642 dfrag = mptcp_pending_tail(sk);
1643 dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag);
1644 if (!dfrag_collapsed) {
1645 if (!sk_stream_memory_free(sk))
1646 goto wait_for_memory;
1648 if (!mptcp_page_frag_refill(sk, pfrag))
1649 goto wait_for_memory;
1651 dfrag = mptcp_carve_data_frag(msk, pfrag, pfrag->offset);
1652 frag_truesize = dfrag->overhead;
1655 /* we do not bound vs wspace, to allow a single packet.
1656 * memory accounting will prevent execessive memory usage
1659 offset = dfrag->offset + dfrag->data_len;
1660 psize = pfrag->size - offset;
1661 psize = min_t(size_t, psize, msg_data_left(msg));
1662 total_ts = psize + frag_truesize;
1663 __skb_queue_head_init(&skbs);
1664 if (!mptcp_tx_cache_refill(sk, psize, &skbs, &total_ts))
1665 goto wait_for_memory;
1667 if (!mptcp_wmem_alloc(sk, total_ts)) {
1668 __skb_queue_purge(&skbs);
1669 goto wait_for_memory;
1672 skb_queue_splice_tail(&skbs, &msk->skb_tx_cache);
1673 if (copy_page_from_iter(dfrag->page, offset, psize,
1674 &msg->msg_iter) != psize) {
1675 mptcp_wmem_uncharge(sk, psize + frag_truesize);
1680 /* data successfully copied into the write queue */
1682 dfrag->data_len += psize;
1683 frag_truesize += psize;
1684 pfrag->offset += frag_truesize;
1685 WRITE_ONCE(msk->write_seq, msk->write_seq + psize);
1686 msk->tx_pending_data += psize;
1688 /* charge data on mptcp pending queue to the msk socket
1689 * Note: we charge such data both to sk and ssk
1691 sk_wmem_queued_add(sk, frag_truesize);
1692 if (!dfrag_collapsed) {
1693 get_page(dfrag->page);
1694 list_add_tail(&dfrag->list, &msk->rtx_queue);
1695 if (!msk->first_pending)
1696 WRITE_ONCE(msk->first_pending, dfrag);
1698 pr_debug("msk=%p dfrag at seq=%lld len=%d sent=%d new=%d", msk,
1699 dfrag->data_seq, dfrag->data_len, dfrag->already_sent,
1705 mptcp_set_nospace(sk);
1706 __mptcp_push_pending(sk, msg->msg_flags);
1707 ret = sk_stream_wait_memory(sk, &timeo);
1713 __mptcp_push_pending(sk, msg->msg_flags);
1717 return copied ? : ret;
1720 static void mptcp_wait_data(struct sock *sk, long *timeo)
1722 DEFINE_WAIT_FUNC(wait, woken_wake_function);
1723 struct mptcp_sock *msk = mptcp_sk(sk);
1725 add_wait_queue(sk_sleep(sk), &wait);
1726 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
1728 sk_wait_event(sk, timeo,
1729 test_and_clear_bit(MPTCP_DATA_READY, &msk->flags), &wait);
1731 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
1732 remove_wait_queue(sk_sleep(sk), &wait);
1735 static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk,
1739 struct sk_buff *skb;
1742 while ((skb = skb_peek(&msk->receive_queue)) != NULL) {
1743 u32 offset = MPTCP_SKB_CB(skb)->offset;
1744 u32 data_len = skb->len - offset;
1745 u32 count = min_t(size_t, len - copied, data_len);
1748 err = skb_copy_datagram_msg(skb, offset, msg, count);
1749 if (unlikely(err < 0)) {
1757 if (count < data_len) {
1758 MPTCP_SKB_CB(skb)->offset += count;
1762 /* we will bulk release the skb memory later */
1763 skb->destructor = NULL;
1764 msk->rmem_released += skb->truesize;
1765 __skb_unlink(skb, &msk->receive_queue);
1775 /* receive buffer autotuning. See tcp_rcv_space_adjust for more information.
1777 * Only difference: Use highest rtt estimate of the subflows in use.
1779 static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied)
1781 struct mptcp_subflow_context *subflow;
1782 struct sock *sk = (struct sock *)msk;
1783 u32 time, advmss = 1;
1786 sock_owned_by_me(sk);
1791 msk->rcvq_space.copied += copied;
1793 mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC);
1794 time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time);
1796 rtt_us = msk->rcvq_space.rtt_us;
1797 if (rtt_us && time < (rtt_us >> 3))
1801 mptcp_for_each_subflow(msk, subflow) {
1802 const struct tcp_sock *tp;
1806 tp = tcp_sk(mptcp_subflow_tcp_sock(subflow));
1808 sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us);
1809 sf_advmss = READ_ONCE(tp->advmss);
1811 rtt_us = max(sf_rtt_us, rtt_us);
1812 advmss = max(sf_advmss, advmss);
1815 msk->rcvq_space.rtt_us = rtt_us;
1816 if (time < (rtt_us >> 3) || rtt_us == 0)
1819 if (msk->rcvq_space.copied <= msk->rcvq_space.space)
1822 if (sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf &&
1823 !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
1827 rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss;
1829 grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space);
1831 do_div(grow, msk->rcvq_space.space);
1832 rcvwin += (grow << 1);
1834 rcvmem = SKB_TRUESIZE(advmss + MAX_TCP_HEADER);
1835 while (tcp_win_from_space(sk, rcvmem) < advmss)
1838 do_div(rcvwin, advmss);
1839 rcvbuf = min_t(u64, rcvwin * rcvmem,
1840 sock_net(sk)->ipv4.sysctl_tcp_rmem[2]);
1842 if (rcvbuf > sk->sk_rcvbuf) {
1845 window_clamp = tcp_win_from_space(sk, rcvbuf);
1846 WRITE_ONCE(sk->sk_rcvbuf, rcvbuf);
1848 /* Make subflows follow along. If we do not do this, we
1849 * get drops at subflow level if skbs can't be moved to
1850 * the mptcp rx queue fast enough (announced rcv_win can
1851 * exceed ssk->sk_rcvbuf).
1853 mptcp_for_each_subflow(msk, subflow) {
1857 ssk = mptcp_subflow_tcp_sock(subflow);
1858 slow = lock_sock_fast(ssk);
1859 WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf);
1860 tcp_sk(ssk)->window_clamp = window_clamp;
1861 tcp_cleanup_rbuf(ssk, 1);
1862 unlock_sock_fast(ssk, slow);
1867 msk->rcvq_space.space = msk->rcvq_space.copied;
1869 msk->rcvq_space.copied = 0;
1870 msk->rcvq_space.time = mstamp;
1873 static void __mptcp_update_rmem(struct sock *sk)
1875 struct mptcp_sock *msk = mptcp_sk(sk);
1877 if (!msk->rmem_released)
1880 atomic_sub(msk->rmem_released, &sk->sk_rmem_alloc);
1881 sk_mem_uncharge(sk, msk->rmem_released);
1882 msk->rmem_released = 0;
1885 static void __mptcp_splice_receive_queue(struct sock *sk)
1887 struct mptcp_sock *msk = mptcp_sk(sk);
1889 skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue);
1892 static bool __mptcp_move_skbs(struct mptcp_sock *msk)
1894 struct sock *sk = (struct sock *)msk;
1895 unsigned int moved = 0;
1898 __mptcp_flush_join_list(msk);
1900 struct sock *ssk = mptcp_subflow_recv_lookup(msk);
1903 /* we can have data pending in the subflows only if the msk
1904 * receive buffer was full at subflow_data_ready() time,
1905 * that is an unlikely slow path.
1910 slowpath = lock_sock_fast(ssk);
1911 mptcp_data_lock(sk);
1912 __mptcp_update_rmem(sk);
1913 done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
1914 mptcp_data_unlock(sk);
1915 tcp_cleanup_rbuf(ssk, moved);
1916 unlock_sock_fast(ssk, slowpath);
1919 /* acquire the data lock only if some input data is pending */
1921 if (!RB_EMPTY_ROOT(&msk->out_of_order_queue) ||
1922 !skb_queue_empty_lockless(&sk->sk_receive_queue)) {
1923 mptcp_data_lock(sk);
1924 __mptcp_update_rmem(sk);
1925 ret |= __mptcp_ofo_queue(msk);
1926 __mptcp_splice_receive_queue(sk);
1927 mptcp_data_unlock(sk);
1928 mptcp_cleanup_rbuf(msk);
1931 mptcp_check_data_fin((struct sock *)msk);
1932 return !skb_queue_empty(&msk->receive_queue);
1935 static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
1936 int nonblock, int flags, int *addr_len)
1938 struct mptcp_sock *msk = mptcp_sk(sk);
1943 if (msg->msg_flags & ~(MSG_WAITALL | MSG_DONTWAIT))
1946 mptcp_lock_sock(sk, __mptcp_splice_receive_queue(sk));
1947 if (unlikely(sk->sk_state == TCP_LISTEN)) {
1952 timeo = sock_rcvtimeo(sk, nonblock);
1954 len = min_t(size_t, len, INT_MAX);
1955 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1957 while (copied < len) {
1960 bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied);
1961 if (unlikely(bytes_read < 0)) {
1963 copied = bytes_read;
1967 copied += bytes_read;
1969 /* be sure to advertise window change */
1970 mptcp_cleanup_rbuf(msk);
1972 if (skb_queue_empty(&msk->receive_queue) && __mptcp_move_skbs(msk))
1975 /* only the master socket status is relevant here. The exit
1976 * conditions mirror closely tcp_recvmsg()
1978 if (copied >= target)
1983 sk->sk_state == TCP_CLOSE ||
1984 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1986 signal_pending(current))
1990 copied = sock_error(sk);
1994 if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
1995 mptcp_check_for_eof(msk);
1997 if (sk->sk_shutdown & RCV_SHUTDOWN) {
1998 /* race breaker: the shutdown could be after the
1999 * previous receive queue check
2001 if (__mptcp_move_skbs(msk))
2006 if (sk->sk_state == TCP_CLOSE) {
2016 if (signal_pending(current)) {
2017 copied = sock_intr_errno(timeo);
2022 pr_debug("block timeout %ld", timeo);
2023 mptcp_wait_data(sk, &timeo);
2026 if (skb_queue_empty_lockless(&sk->sk_receive_queue) &&
2027 skb_queue_empty(&msk->receive_queue)) {
2028 /* entire backlog drained, clear DATA_READY. */
2029 clear_bit(MPTCP_DATA_READY, &msk->flags);
2031 /* .. race-breaker: ssk might have gotten new data
2032 * after last __mptcp_move_skbs() returned false.
2034 if (unlikely(__mptcp_move_skbs(msk)))
2035 set_bit(MPTCP_DATA_READY, &msk->flags);
2036 } else if (unlikely(!test_bit(MPTCP_DATA_READY, &msk->flags))) {
2037 /* data to read but mptcp_wait_data() cleared DATA_READY */
2038 set_bit(MPTCP_DATA_READY, &msk->flags);
2041 pr_debug("msk=%p data_ready=%d rx queue empty=%d copied=%d",
2042 msk, test_bit(MPTCP_DATA_READY, &msk->flags),
2043 skb_queue_empty_lockless(&sk->sk_receive_queue), copied);
2044 mptcp_rcv_space_adjust(msk, copied);
2050 static void mptcp_retransmit_handler(struct sock *sk)
2052 struct mptcp_sock *msk = mptcp_sk(sk);
2054 set_bit(MPTCP_WORK_RTX, &msk->flags);
2055 mptcp_schedule_work(sk);
2058 static void mptcp_retransmit_timer(struct timer_list *t)
2060 struct inet_connection_sock *icsk = from_timer(icsk, t,
2061 icsk_retransmit_timer);
2062 struct sock *sk = &icsk->icsk_inet.sk;
2065 if (!sock_owned_by_user(sk)) {
2066 mptcp_retransmit_handler(sk);
2068 /* delegate our work to tcp_release_cb() */
2069 if (!test_and_set_bit(TCP_WRITE_TIMER_DEFERRED,
2077 static void mptcp_timeout_timer(struct timer_list *t)
2079 struct sock *sk = from_timer(sk, t, sk_timer);
2081 mptcp_schedule_work(sk);
2085 /* Find an idle subflow. Return NULL if there is unacked data at tcp
2088 * A backup subflow is returned only if that is the only kind available.
2090 static struct sock *mptcp_subflow_get_retrans(const struct mptcp_sock *msk)
2092 struct mptcp_subflow_context *subflow;
2093 struct sock *backup = NULL;
2095 sock_owned_by_me((const struct sock *)msk);
2097 if (__mptcp_check_fallback(msk))
2100 mptcp_for_each_subflow(msk, subflow) {
2101 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2103 if (!mptcp_subflow_active(subflow))
2106 /* still data outstanding at TCP level? Don't retransmit. */
2107 if (!tcp_write_queue_empty(ssk)) {
2108 if (inet_csk(ssk)->icsk_ca_state >= TCP_CA_Loss)
2113 if (subflow->backup) {
2125 static void mptcp_dispose_initial_subflow(struct mptcp_sock *msk)
2128 iput(SOCK_INODE(msk->subflow));
2129 msk->subflow = NULL;
2133 /* subflow sockets can be either outgoing (connect) or incoming
2136 * Outgoing subflows use in-kernel sockets.
2137 * Incoming subflows do not have their own 'struct socket' allocated,
2138 * so we need to use tcp_close() after detaching them from the mptcp
2141 static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
2142 struct mptcp_subflow_context *subflow)
2144 struct mptcp_sock *msk = mptcp_sk(sk);
2146 list_del(&subflow->node);
2148 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
2150 /* if we are invoked by the msk cleanup code, the subflow is
2156 subflow->disposable = 1;
2158 /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops
2159 * the ssk has been already destroyed, we just need to release the
2160 * reference owned by msk;
2162 if (!inet_csk(ssk)->icsk_ulp_ops) {
2163 kfree_rcu(subflow, rcu);
2165 /* otherwise tcp will dispose of the ssk and subflow ctx */
2166 __tcp_close(ssk, 0);
2168 /* close acquired an extra ref */
2175 if (ssk == msk->last_snd)
2176 msk->last_snd = NULL;
2178 if (ssk == msk->ack_hint)
2179 msk->ack_hint = NULL;
2181 if (ssk == msk->first)
2184 if (msk->subflow && ssk == msk->subflow->sk)
2185 mptcp_dispose_initial_subflow(msk);
2188 void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
2189 struct mptcp_subflow_context *subflow)
2191 if (sk->sk_state == TCP_ESTABLISHED)
2192 mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL);
2193 __mptcp_close_ssk(sk, ssk, subflow);
2196 static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu)
2201 static void __mptcp_close_subflow(struct mptcp_sock *msk)
2203 struct mptcp_subflow_context *subflow, *tmp;
2207 list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
2208 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2210 if (inet_sk_state_load(ssk) != TCP_CLOSE)
2213 /* 'subflow_data_ready' will re-sched once rx queue is empty */
2214 if (!skb_queue_empty_lockless(&ssk->sk_receive_queue))
2217 mptcp_close_ssk((struct sock *)msk, ssk, subflow);
2221 static bool mptcp_check_close_timeout(const struct sock *sk)
2223 s32 delta = tcp_jiffies32 - inet_csk(sk)->icsk_mtup.probe_timestamp;
2224 struct mptcp_subflow_context *subflow;
2226 if (delta >= TCP_TIMEWAIT_LEN)
2229 /* if all subflows are in closed status don't bother with additional
2232 mptcp_for_each_subflow(mptcp_sk(sk), subflow) {
2233 if (inet_sk_state_load(mptcp_subflow_tcp_sock(subflow)) !=
2240 static void mptcp_check_fastclose(struct mptcp_sock *msk)
2242 struct mptcp_subflow_context *subflow, *tmp;
2243 struct sock *sk = &msk->sk.icsk_inet.sk;
2245 if (likely(!READ_ONCE(msk->rcv_fastclose)))
2248 mptcp_token_destroy(msk);
2250 list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
2251 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
2254 if (tcp_sk->sk_state != TCP_CLOSE) {
2255 tcp_send_active_reset(tcp_sk, GFP_ATOMIC);
2256 tcp_set_state(tcp_sk, TCP_CLOSE);
2258 release_sock(tcp_sk);
2261 inet_sk_state_store(sk, TCP_CLOSE);
2262 sk->sk_shutdown = SHUTDOWN_MASK;
2263 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
2264 set_bit(MPTCP_DATA_READY, &msk->flags);
2265 set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags);
2267 mptcp_close_wake_up(sk);
2270 static void __mptcp_retrans(struct sock *sk)
2272 struct mptcp_sock *msk = mptcp_sk(sk);
2273 struct mptcp_sendmsg_info info = {};
2274 struct mptcp_data_frag *dfrag;
2279 __mptcp_clean_una_wakeup(sk);
2280 dfrag = mptcp_rtx_head(sk);
2284 ssk = mptcp_subflow_get_retrans(msk);
2290 /* limit retransmission to the bytes already sent on some subflows */
2292 info.limit = dfrag->already_sent;
2293 while (info.sent < dfrag->already_sent) {
2294 if (!mptcp_alloc_tx_skb(sk, ssk))
2297 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
2301 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS);
2306 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
2309 mptcp_set_timeout(sk, ssk);
2313 if (!mptcp_timer_pending(sk))
2314 mptcp_reset_timer(sk);
2317 static void mptcp_worker(struct work_struct *work)
2319 struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
2320 struct sock *sk = &msk->sk.icsk_inet.sk;
2324 state = sk->sk_state;
2325 if (unlikely(state == TCP_CLOSE))
2328 mptcp_check_data_fin_ack(sk);
2329 __mptcp_flush_join_list(msk);
2331 mptcp_check_fastclose(msk);
2334 mptcp_pm_nl_work(msk);
2336 if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
2337 mptcp_check_for_eof(msk);
2339 __mptcp_check_send_data_fin(sk);
2340 mptcp_check_data_fin(sk);
2342 /* There is no point in keeping around an orphaned sk timedout or
2343 * closed, but we need the msk around to reply to incoming DATA_FIN,
2344 * even if it is orphaned and in FIN_WAIT2 state
2346 if (sock_flag(sk, SOCK_DEAD) &&
2347 (mptcp_check_close_timeout(sk) || sk->sk_state == TCP_CLOSE)) {
2348 inet_sk_state_store(sk, TCP_CLOSE);
2349 __mptcp_destroy_sock(sk);
2353 if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
2354 __mptcp_close_subflow(msk);
2356 if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
2357 __mptcp_retrans(sk);
2364 static int __mptcp_init_sock(struct sock *sk)
2366 struct mptcp_sock *msk = mptcp_sk(sk);
2368 spin_lock_init(&msk->join_list_lock);
2370 INIT_LIST_HEAD(&msk->conn_list);
2371 INIT_LIST_HEAD(&msk->join_list);
2372 INIT_LIST_HEAD(&msk->rtx_queue);
2373 INIT_WORK(&msk->work, mptcp_worker);
2374 __skb_queue_head_init(&msk->receive_queue);
2375 __skb_queue_head_init(&msk->skb_tx_cache);
2376 msk->out_of_order_queue = RB_ROOT;
2377 msk->first_pending = NULL;
2378 msk->wmem_reserved = 0;
2379 msk->rmem_released = 0;
2380 msk->tx_pending_data = 0;
2381 msk->size_goal_cache = TCP_BASE_MSS;
2383 msk->ack_hint = NULL;
2385 inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss;
2387 mptcp_pm_data_init(msk);
2389 /* re-use the csk retrans timer for MPTCP-level retrans */
2390 timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0);
2391 timer_setup(&sk->sk_timer, mptcp_timeout_timer, 0);
2395 static int mptcp_init_sock(struct sock *sk)
2397 struct net *net = sock_net(sk);
2400 ret = __mptcp_init_sock(sk);
2404 if (!mptcp_is_enabled(net))
2405 return -ENOPROTOOPT;
2407 if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net))
2410 ret = __mptcp_socket_create(mptcp_sk(sk));
2414 sk_sockets_allocated_inc(sk);
2415 sk->sk_rcvbuf = sock_net(sk)->ipv4.sysctl_tcp_rmem[1];
2416 sk->sk_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[1];
2421 static void __mptcp_clear_xmit(struct sock *sk)
2423 struct mptcp_sock *msk = mptcp_sk(sk);
2424 struct mptcp_data_frag *dtmp, *dfrag;
2425 struct sk_buff *skb;
2427 WRITE_ONCE(msk->first_pending, NULL);
2428 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list)
2429 dfrag_clear(sk, dfrag);
2430 while ((skb = __skb_dequeue(&msk->skb_tx_cache)) != NULL) {
2431 sk->sk_forward_alloc += skb->truesize;
2436 static void mptcp_cancel_work(struct sock *sk)
2438 struct mptcp_sock *msk = mptcp_sk(sk);
2440 if (cancel_work_sync(&msk->work))
2444 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how)
2448 switch (ssk->sk_state) {
2450 if (!(how & RCV_SHUTDOWN))
2454 tcp_disconnect(ssk, O_NONBLOCK);
2457 if (__mptcp_check_fallback(mptcp_sk(sk))) {
2458 pr_debug("Fallback");
2459 ssk->sk_shutdown |= how;
2460 tcp_shutdown(ssk, how);
2462 pr_debug("Sending DATA_FIN on subflow %p", ssk);
2463 mptcp_set_timeout(sk, ssk);
2472 static const unsigned char new_state[16] = {
2473 /* current state: new state: action: */
2474 [0 /* (Invalid) */] = TCP_CLOSE,
2475 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2476 [TCP_SYN_SENT] = TCP_CLOSE,
2477 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2478 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1,
2479 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2,
2480 [TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */
2481 [TCP_CLOSE] = TCP_CLOSE,
2482 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN,
2483 [TCP_LAST_ACK] = TCP_LAST_ACK,
2484 [TCP_LISTEN] = TCP_CLOSE,
2485 [TCP_CLOSING] = TCP_CLOSING,
2486 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */
2489 static int mptcp_close_state(struct sock *sk)
2491 int next = (int)new_state[sk->sk_state];
2492 int ns = next & TCP_STATE_MASK;
2494 inet_sk_state_store(sk, ns);
2496 return next & TCP_ACTION_FIN;
2499 static void __mptcp_check_send_data_fin(struct sock *sk)
2501 struct mptcp_subflow_context *subflow;
2502 struct mptcp_sock *msk = mptcp_sk(sk);
2504 pr_debug("msk=%p snd_data_fin_enable=%d pending=%d snd_nxt=%llu write_seq=%llu",
2505 msk, msk->snd_data_fin_enable, !!mptcp_send_head(sk),
2506 msk->snd_nxt, msk->write_seq);
2508 /* we still need to enqueue subflows or not really shutting down,
2511 if (!msk->snd_data_fin_enable || msk->snd_nxt + 1 != msk->write_seq ||
2512 mptcp_send_head(sk))
2515 WRITE_ONCE(msk->snd_nxt, msk->write_seq);
2517 /* fallback socket will not get data_fin/ack, can move to the next
2520 if (__mptcp_check_fallback(msk)) {
2521 if ((1 << sk->sk_state) & (TCPF_CLOSING | TCPF_LAST_ACK)) {
2522 inet_sk_state_store(sk, TCP_CLOSE);
2523 mptcp_close_wake_up(sk);
2524 } else if (sk->sk_state == TCP_FIN_WAIT1) {
2525 inet_sk_state_store(sk, TCP_FIN_WAIT2);
2529 __mptcp_flush_join_list(msk);
2530 mptcp_for_each_subflow(msk, subflow) {
2531 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
2533 mptcp_subflow_shutdown(sk, tcp_sk, SEND_SHUTDOWN);
2537 static void __mptcp_wr_shutdown(struct sock *sk)
2539 struct mptcp_sock *msk = mptcp_sk(sk);
2541 pr_debug("msk=%p snd_data_fin_enable=%d shutdown=%x state=%d pending=%d",
2542 msk, msk->snd_data_fin_enable, sk->sk_shutdown, sk->sk_state,
2543 !!mptcp_send_head(sk));
2545 /* will be ignored by fallback sockets */
2546 WRITE_ONCE(msk->write_seq, msk->write_seq + 1);
2547 WRITE_ONCE(msk->snd_data_fin_enable, 1);
2549 __mptcp_check_send_data_fin(sk);
2552 static void __mptcp_destroy_sock(struct sock *sk)
2554 struct mptcp_subflow_context *subflow, *tmp;
2555 struct mptcp_sock *msk = mptcp_sk(sk);
2556 LIST_HEAD(conn_list);
2558 pr_debug("msk=%p", msk);
2562 /* be sure to always acquire the join list lock, to sync vs
2563 * mptcp_finish_join().
2565 spin_lock_bh(&msk->join_list_lock);
2566 list_splice_tail_init(&msk->join_list, &msk->conn_list);
2567 spin_unlock_bh(&msk->join_list_lock);
2568 list_splice_init(&msk->conn_list, &conn_list);
2570 sk_stop_timer(sk, &msk->sk.icsk_retransmit_timer);
2571 sk_stop_timer(sk, &sk->sk_timer);
2574 list_for_each_entry_safe(subflow, tmp, &conn_list, node) {
2575 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2576 __mptcp_close_ssk(sk, ssk, subflow);
2579 sk->sk_prot->destroy(sk);
2581 WARN_ON_ONCE(msk->wmem_reserved);
2582 WARN_ON_ONCE(msk->rmem_released);
2583 sk_stream_kill_queues(sk);
2584 xfrm_sk_free_policy(sk);
2585 sk_refcnt_debug_release(sk);
2586 mptcp_dispose_initial_subflow(msk);
2590 static void mptcp_close(struct sock *sk, long timeout)
2592 struct mptcp_subflow_context *subflow;
2593 bool do_cancel_work = false;
2596 sk->sk_shutdown = SHUTDOWN_MASK;
2598 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) {
2599 inet_sk_state_store(sk, TCP_CLOSE);
2603 if (mptcp_close_state(sk))
2604 __mptcp_wr_shutdown(sk);
2606 sk_stream_wait_close(sk, timeout);
2609 /* orphan all the subflows */
2610 inet_csk(sk)->icsk_mtup.probe_timestamp = tcp_jiffies32;
2611 list_for_each_entry(subflow, &mptcp_sk(sk)->conn_list, node) {
2612 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2613 bool slow = lock_sock_fast(ssk);
2616 unlock_sock_fast(ssk, slow);
2621 pr_debug("msk=%p state=%d", sk, sk->sk_state);
2622 if (sk->sk_state == TCP_CLOSE) {
2623 __mptcp_destroy_sock(sk);
2624 do_cancel_work = true;
2626 sk_reset_timer(sk, &sk->sk_timer, jiffies + TCP_TIMEWAIT_LEN);
2630 mptcp_cancel_work(sk);
2632 if (mptcp_sk(sk)->token)
2633 mptcp_event(MPTCP_EVENT_CLOSED, mptcp_sk(sk), NULL, GFP_KERNEL);
2638 static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk)
2640 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
2641 const struct ipv6_pinfo *ssk6 = inet6_sk(ssk);
2642 struct ipv6_pinfo *msk6 = inet6_sk(msk);
2644 msk->sk_v6_daddr = ssk->sk_v6_daddr;
2645 msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr;
2648 msk6->saddr = ssk6->saddr;
2649 msk6->flow_label = ssk6->flow_label;
2653 inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num;
2654 inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport;
2655 inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport;
2656 inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr;
2657 inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr;
2658 inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr;
2661 static int mptcp_disconnect(struct sock *sk, int flags)
2663 struct mptcp_subflow_context *subflow;
2664 struct mptcp_sock *msk = mptcp_sk(sk);
2666 __mptcp_flush_join_list(msk);
2667 mptcp_for_each_subflow(msk, subflow) {
2668 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2671 tcp_disconnect(ssk, flags);
2677 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
2678 static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk)
2680 unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo);
2682 return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
2686 struct sock *mptcp_sk_clone(const struct sock *sk,
2687 const struct mptcp_options_received *mp_opt,
2688 struct request_sock *req)
2690 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
2691 struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC);
2692 struct mptcp_sock *msk;
2698 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
2699 if (nsk->sk_family == AF_INET6)
2700 inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk);
2703 __mptcp_init_sock(nsk);
2705 msk = mptcp_sk(nsk);
2706 msk->local_key = subflow_req->local_key;
2707 msk->token = subflow_req->token;
2708 msk->subflow = NULL;
2709 WRITE_ONCE(msk->fully_established, false);
2711 msk->write_seq = subflow_req->idsn + 1;
2712 msk->snd_nxt = msk->write_seq;
2713 msk->snd_una = msk->write_seq;
2714 msk->wnd_end = msk->snd_nxt + req->rsk_rcv_wnd;
2716 if (mp_opt->mp_capable) {
2717 msk->can_ack = true;
2718 msk->remote_key = mp_opt->sndr_key;
2719 mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq);
2721 WRITE_ONCE(msk->ack_seq, ack_seq);
2722 WRITE_ONCE(msk->rcv_wnd_sent, ack_seq);
2725 sock_reset_flag(nsk, SOCK_RCU_FREE);
2726 /* will be fully established after successful MPC subflow creation */
2727 inet_sk_state_store(nsk, TCP_SYN_RECV);
2729 security_inet_csk_clone(nsk, req);
2730 bh_unlock_sock(nsk);
2732 /* keep a single reference */
2737 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk)
2739 const struct tcp_sock *tp = tcp_sk(ssk);
2741 msk->rcvq_space.copied = 0;
2742 msk->rcvq_space.rtt_us = 0;
2744 msk->rcvq_space.time = tp->tcp_mstamp;
2746 /* initial rcv_space offering made to peer */
2747 msk->rcvq_space.space = min_t(u32, tp->rcv_wnd,
2748 TCP_INIT_CWND * tp->advmss);
2749 if (msk->rcvq_space.space == 0)
2750 msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT;
2752 WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd);
2755 static struct sock *mptcp_accept(struct sock *sk, int flags, int *err,
2758 struct mptcp_sock *msk = mptcp_sk(sk);
2759 struct socket *listener;
2762 listener = __mptcp_nmpc_socket(msk);
2763 if (WARN_ON_ONCE(!listener)) {
2768 pr_debug("msk=%p, listener=%p", msk, mptcp_subflow_ctx(listener->sk));
2769 newsk = inet_csk_accept(listener->sk, flags, err, kern);
2773 pr_debug("msk=%p, subflow is mptcp=%d", msk, sk_is_mptcp(newsk));
2774 if (sk_is_mptcp(newsk)) {
2775 struct mptcp_subflow_context *subflow;
2776 struct sock *new_mptcp_sock;
2778 subflow = mptcp_subflow_ctx(newsk);
2779 new_mptcp_sock = subflow->conn;
2781 /* is_mptcp should be false if subflow->conn is missing, see
2782 * subflow_syn_recv_sock()
2784 if (WARN_ON_ONCE(!new_mptcp_sock)) {
2785 tcp_sk(newsk)->is_mptcp = 0;
2789 /* acquire the 2nd reference for the owning socket */
2790 sock_hold(new_mptcp_sock);
2791 newsk = new_mptcp_sock;
2792 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEPASSIVEACK);
2794 MPTCP_INC_STATS(sock_net(sk),
2795 MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK);
2801 void mptcp_destroy_common(struct mptcp_sock *msk)
2803 struct sock *sk = (struct sock *)msk;
2805 __mptcp_clear_xmit(sk);
2807 /* move to sk_receive_queue, sk_stream_kill_queues will purge it */
2808 skb_queue_splice_tail_init(&msk->receive_queue, &sk->sk_receive_queue);
2810 skb_rbtree_purge(&msk->out_of_order_queue);
2811 mptcp_token_destroy(msk);
2812 mptcp_pm_free_anno_list(msk);
2815 static void mptcp_destroy(struct sock *sk)
2817 struct mptcp_sock *msk = mptcp_sk(sk);
2819 mptcp_destroy_common(msk);
2820 sk_sockets_allocated_dec(sk);
2823 static int mptcp_setsockopt_sol_socket(struct mptcp_sock *msk, int optname,
2824 sockptr_t optval, unsigned int optlen)
2826 struct sock *sk = (struct sock *)msk;
2827 struct socket *ssock;
2834 ssock = __mptcp_nmpc_socket(msk);
2840 ret = sock_setsockopt(ssock, SOL_SOCKET, optname, optval, optlen);
2842 if (optname == SO_REUSEPORT)
2843 sk->sk_reuseport = ssock->sk->sk_reuseport;
2844 else if (optname == SO_REUSEADDR)
2845 sk->sk_reuse = ssock->sk->sk_reuse;
2851 return sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname, optval, optlen);
2854 static int mptcp_setsockopt_v6(struct mptcp_sock *msk, int optname,
2855 sockptr_t optval, unsigned int optlen)
2857 struct sock *sk = (struct sock *)msk;
2858 int ret = -EOPNOTSUPP;
2859 struct socket *ssock;
2864 ssock = __mptcp_nmpc_socket(msk);
2870 ret = tcp_setsockopt(ssock->sk, SOL_IPV6, optname, optval, optlen);
2872 sk->sk_ipv6only = ssock->sk->sk_ipv6only;
2881 static int mptcp_setsockopt(struct sock *sk, int level, int optname,
2882 sockptr_t optval, unsigned int optlen)
2884 struct mptcp_sock *msk = mptcp_sk(sk);
2887 pr_debug("msk=%p", msk);
2889 if (level == SOL_SOCKET)
2890 return mptcp_setsockopt_sol_socket(msk, optname, optval, optlen);
2892 /* @@ the meaning of setsockopt() when the socket is connected and
2893 * there are multiple subflows is not yet defined. It is up to the
2894 * MPTCP-level socket to configure the subflows until the subflow
2895 * is in TCP fallback, when TCP socket options are passed through
2896 * to the one remaining subflow.
2899 ssk = __mptcp_tcp_fallback(msk);
2902 return tcp_setsockopt(ssk, level, optname, optval, optlen);
2904 if (level == SOL_IPV6)
2905 return mptcp_setsockopt_v6(msk, optname, optval, optlen);
2910 static int mptcp_getsockopt(struct sock *sk, int level, int optname,
2911 char __user *optval, int __user *option)
2913 struct mptcp_sock *msk = mptcp_sk(sk);
2916 pr_debug("msk=%p", msk);
2918 /* @@ the meaning of setsockopt() when the socket is connected and
2919 * there are multiple subflows is not yet defined. It is up to the
2920 * MPTCP-level socket to configure the subflows until the subflow
2921 * is in TCP fallback, when socket options are passed through
2922 * to the one remaining subflow.
2925 ssk = __mptcp_tcp_fallback(msk);
2928 return tcp_getsockopt(ssk, level, optname, optval, option);
2933 void __mptcp_data_acked(struct sock *sk)
2935 if (!sock_owned_by_user(sk))
2936 __mptcp_clean_una(sk);
2938 set_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->flags);
2940 if (mptcp_pending_data_fin_ack(sk))
2941 mptcp_schedule_work(sk);
2944 void __mptcp_check_push(struct sock *sk, struct sock *ssk)
2946 if (!mptcp_send_head(sk))
2949 if (!sock_owned_by_user(sk)) {
2950 struct sock *xmit_ssk = mptcp_subflow_get_send(mptcp_sk(sk));
2952 if (xmit_ssk == ssk)
2953 __mptcp_subflow_push_pending(sk, ssk);
2955 mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk));
2957 set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags);
2961 #define MPTCP_DEFERRED_ALL (TCPF_WRITE_TIMER_DEFERRED)
2963 /* processes deferred events and flush wmem */
2964 static void mptcp_release_cb(struct sock *sk)
2966 unsigned long flags, nflags;
2970 if (test_and_clear_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags))
2971 flags |= MPTCP_PUSH_PENDING;
2975 /* the following actions acquire the subflow socket lock
2977 * 1) can't be invoked in atomic scope
2978 * 2) must avoid ABBA deadlock with msk socket spinlock: the RX
2979 * datapath acquires the msk socket spinlock while helding
2980 * the subflow socket lock
2983 spin_unlock_bh(&sk->sk_lock.slock);
2984 if (flags & MPTCP_PUSH_PENDING)
2985 __mptcp_push_pending(sk, 0);
2988 spin_lock_bh(&sk->sk_lock.slock);
2991 if (test_and_clear_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->flags))
2992 __mptcp_clean_una_wakeup(sk);
2993 if (test_and_clear_bit(MPTCP_ERROR_REPORT, &mptcp_sk(sk)->flags))
2994 __mptcp_error_report(sk);
2996 /* push_pending may touch wmem_reserved, ensure we do the cleanup
2999 __mptcp_update_wmem(sk);
3000 __mptcp_update_rmem(sk);
3003 flags = sk->sk_tsq_flags;
3004 if (!(flags & MPTCP_DEFERRED_ALL))
3006 nflags = flags & ~MPTCP_DEFERRED_ALL;
3007 } while (cmpxchg(&sk->sk_tsq_flags, flags, nflags) != flags);
3009 sock_release_ownership(sk);
3011 if (flags & TCPF_WRITE_TIMER_DEFERRED) {
3012 mptcp_retransmit_handler(sk);
3017 void mptcp_subflow_process_delegated(struct sock *ssk)
3019 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
3020 struct sock *sk = subflow->conn;
3022 mptcp_data_lock(sk);
3023 if (!sock_owned_by_user(sk))
3024 __mptcp_subflow_push_pending(sk, ssk);
3026 set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags);
3027 mptcp_data_unlock(sk);
3028 mptcp_subflow_delegated_done(subflow);
3031 static int mptcp_hash(struct sock *sk)
3033 /* should never be called,
3034 * we hash the TCP subflows not the master socket
3040 static void mptcp_unhash(struct sock *sk)
3042 /* called from sk_common_release(), but nothing to do here */
3045 static int mptcp_get_port(struct sock *sk, unsigned short snum)
3047 struct mptcp_sock *msk = mptcp_sk(sk);
3048 struct socket *ssock;
3050 ssock = __mptcp_nmpc_socket(msk);
3051 pr_debug("msk=%p, subflow=%p", msk, ssock);
3052 if (WARN_ON_ONCE(!ssock))
3055 return inet_csk_get_port(ssock->sk, snum);
3058 void mptcp_finish_connect(struct sock *ssk)
3060 struct mptcp_subflow_context *subflow;
3061 struct mptcp_sock *msk;
3065 subflow = mptcp_subflow_ctx(ssk);
3069 pr_debug("msk=%p, token=%u", sk, subflow->token);
3071 mptcp_crypto_key_sha(subflow->remote_key, NULL, &ack_seq);
3073 subflow->map_seq = ack_seq;
3074 subflow->map_subflow_seq = 1;
3076 /* the socket is not connected yet, no msk/subflow ops can access/race
3077 * accessing the field below
3079 WRITE_ONCE(msk->remote_key, subflow->remote_key);
3080 WRITE_ONCE(msk->local_key, subflow->local_key);
3081 WRITE_ONCE(msk->write_seq, subflow->idsn + 1);
3082 WRITE_ONCE(msk->snd_nxt, msk->write_seq);
3083 WRITE_ONCE(msk->ack_seq, ack_seq);
3084 WRITE_ONCE(msk->rcv_wnd_sent, ack_seq);
3085 WRITE_ONCE(msk->can_ack, 1);
3086 WRITE_ONCE(msk->snd_una, msk->write_seq);
3088 mptcp_pm_new_connection(msk, ssk, 0);
3090 mptcp_rcv_space_init(msk, ssk);
3093 void mptcp_sock_graft(struct sock *sk, struct socket *parent)
3095 write_lock_bh(&sk->sk_callback_lock);
3096 rcu_assign_pointer(sk->sk_wq, &parent->wq);
3097 sk_set_socket(sk, parent);
3098 sk->sk_uid = SOCK_INODE(parent)->i_uid;
3099 write_unlock_bh(&sk->sk_callback_lock);
3102 bool mptcp_finish_join(struct sock *ssk)
3104 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
3105 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
3106 struct sock *parent = (void *)msk;
3107 struct socket *parent_sock;
3110 pr_debug("msk=%p, subflow=%p", msk, subflow);
3112 /* mptcp socket already closing? */
3113 if (!mptcp_is_fully_established(parent))
3116 if (!msk->pm.server_side)
3119 if (!mptcp_pm_allow_new_subflow(msk))
3122 /* active connections are already on conn_list, and we can't acquire
3124 * use the join list lock as synchronization point and double-check
3125 * msk status to avoid racing with __mptcp_destroy_sock()
3127 spin_lock_bh(&msk->join_list_lock);
3128 ret = inet_sk_state_load(parent) == TCP_ESTABLISHED;
3129 if (ret && !WARN_ON_ONCE(!list_empty(&subflow->node))) {
3130 list_add_tail(&subflow->node, &msk->join_list);
3133 spin_unlock_bh(&msk->join_list_lock);
3137 /* attach to msk socket only after we are sure he will deal with us
3140 parent_sock = READ_ONCE(parent->sk_socket);
3141 if (parent_sock && !ssk->sk_socket)
3142 mptcp_sock_graft(ssk, parent_sock);
3143 subflow->map_seq = READ_ONCE(msk->ack_seq);
3145 mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC);
3149 static void mptcp_shutdown(struct sock *sk, int how)
3151 pr_debug("sk=%p, how=%d", sk, how);
3153 if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk))
3154 __mptcp_wr_shutdown(sk);
3157 static struct proto mptcp_prot = {
3159 .owner = THIS_MODULE,
3160 .init = mptcp_init_sock,
3161 .disconnect = mptcp_disconnect,
3162 .close = mptcp_close,
3163 .accept = mptcp_accept,
3164 .setsockopt = mptcp_setsockopt,
3165 .getsockopt = mptcp_getsockopt,
3166 .shutdown = mptcp_shutdown,
3167 .destroy = mptcp_destroy,
3168 .sendmsg = mptcp_sendmsg,
3169 .recvmsg = mptcp_recvmsg,
3170 .release_cb = mptcp_release_cb,
3172 .unhash = mptcp_unhash,
3173 .get_port = mptcp_get_port,
3174 .sockets_allocated = &mptcp_sockets_allocated,
3175 .memory_allocated = &tcp_memory_allocated,
3176 .memory_pressure = &tcp_memory_pressure,
3177 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
3178 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
3179 .sysctl_mem = sysctl_tcp_mem,
3180 .obj_size = sizeof(struct mptcp_sock),
3181 .slab_flags = SLAB_TYPESAFE_BY_RCU,
3182 .no_autobind = true,
3185 static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
3187 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3188 struct socket *ssock;
3191 lock_sock(sock->sk);
3192 ssock = __mptcp_nmpc_socket(msk);
3198 err = ssock->ops->bind(ssock, uaddr, addr_len);
3200 mptcp_copy_inaddrs(sock->sk, ssock->sk);
3203 release_sock(sock->sk);
3207 static void mptcp_subflow_early_fallback(struct mptcp_sock *msk,
3208 struct mptcp_subflow_context *subflow)
3210 subflow->request_mptcp = 0;
3211 __mptcp_do_fallback(msk);
3214 static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
3215 int addr_len, int flags)
3217 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3218 struct mptcp_subflow_context *subflow;
3219 struct socket *ssock;
3222 lock_sock(sock->sk);
3223 if (sock->state != SS_UNCONNECTED && msk->subflow) {
3224 /* pending connection or invalid state, let existing subflow
3227 ssock = msk->subflow;
3231 ssock = __mptcp_nmpc_socket(msk);
3237 mptcp_token_destroy(msk);
3238 inet_sk_state_store(sock->sk, TCP_SYN_SENT);
3239 subflow = mptcp_subflow_ctx(ssock->sk);
3240 #ifdef CONFIG_TCP_MD5SIG
3241 /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
3244 if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info))
3245 mptcp_subflow_early_fallback(msk, subflow);
3247 if (subflow->request_mptcp && mptcp_token_new_connect(ssock->sk))
3248 mptcp_subflow_early_fallback(msk, subflow);
3251 err = ssock->ops->connect(ssock, uaddr, addr_len, flags);
3252 sock->state = ssock->state;
3254 /* on successful connect, the msk state will be moved to established by
3255 * subflow_finish_connect()
3257 if (!err || err == -EINPROGRESS)
3258 mptcp_copy_inaddrs(sock->sk, ssock->sk);
3260 inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
3263 release_sock(sock->sk);
3267 static int mptcp_listen(struct socket *sock, int backlog)
3269 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3270 struct socket *ssock;
3273 pr_debug("msk=%p", msk);
3275 lock_sock(sock->sk);
3276 ssock = __mptcp_nmpc_socket(msk);
3282 mptcp_token_destroy(msk);
3283 inet_sk_state_store(sock->sk, TCP_LISTEN);
3284 sock_set_flag(sock->sk, SOCK_RCU_FREE);
3286 err = ssock->ops->listen(ssock, backlog);
3287 inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
3289 mptcp_copy_inaddrs(sock->sk, ssock->sk);
3292 release_sock(sock->sk);
3296 static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
3297 int flags, bool kern)
3299 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3300 struct socket *ssock;
3303 pr_debug("msk=%p", msk);
3305 lock_sock(sock->sk);
3306 if (sock->sk->sk_state != TCP_LISTEN)
3309 ssock = __mptcp_nmpc_socket(msk);
3313 clear_bit(MPTCP_DATA_READY, &msk->flags);
3314 sock_hold(ssock->sk);
3315 release_sock(sock->sk);
3317 err = ssock->ops->accept(sock, newsock, flags, kern);
3318 if (err == 0 && !mptcp_is_tcpsk(newsock->sk)) {
3319 struct mptcp_sock *msk = mptcp_sk(newsock->sk);
3320 struct mptcp_subflow_context *subflow;
3321 struct sock *newsk = newsock->sk;
3325 /* PM/worker can now acquire the first subflow socket
3326 * lock without racing with listener queue cleanup,
3327 * we can notify it, if needed.
3329 * Even if remote has reset the initial subflow by now
3330 * the refcnt is still at least one.
3332 subflow = mptcp_subflow_ctx(msk->first);
3333 list_add(&subflow->node, &msk->conn_list);
3334 sock_hold(msk->first);
3335 if (mptcp_is_fully_established(newsk))
3336 mptcp_pm_fully_established(msk, msk->first, GFP_KERNEL);
3338 mptcp_copy_inaddrs(newsk, msk->first);
3339 mptcp_rcv_space_init(msk, msk->first);
3340 mptcp_propagate_sndbuf(newsk, msk->first);
3342 /* set ssk->sk_socket of accept()ed flows to mptcp socket.
3343 * This is needed so NOSPACE flag can be set from tcp stack.
3345 __mptcp_flush_join_list(msk);
3346 mptcp_for_each_subflow(msk, subflow) {
3347 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3349 if (!ssk->sk_socket)
3350 mptcp_sock_graft(ssk, newsock);
3352 release_sock(newsk);
3355 if (inet_csk_listen_poll(ssock->sk))
3356 set_bit(MPTCP_DATA_READY, &msk->flags);
3357 sock_put(ssock->sk);
3361 release_sock(sock->sk);
3365 static __poll_t mptcp_check_readable(struct mptcp_sock *msk)
3367 return test_bit(MPTCP_DATA_READY, &msk->flags) ? EPOLLIN | EPOLLRDNORM :
3371 static __poll_t mptcp_check_writeable(struct mptcp_sock *msk)
3373 struct sock *sk = (struct sock *)msk;
3375 if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
3376 return EPOLLOUT | EPOLLWRNORM;
3378 if (sk_stream_is_writeable(sk))
3379 return EPOLLOUT | EPOLLWRNORM;
3381 mptcp_set_nospace(sk);
3382 smp_mb__after_atomic(); /* msk->flags is changed by write_space cb */
3383 if (sk_stream_is_writeable(sk))
3384 return EPOLLOUT | EPOLLWRNORM;
3389 static __poll_t mptcp_poll(struct file *file, struct socket *sock,
3390 struct poll_table_struct *wait)
3392 struct sock *sk = sock->sk;
3393 struct mptcp_sock *msk;
3398 sock_poll_wait(file, sock, wait);
3400 state = inet_sk_state_load(sk);
3401 pr_debug("msk=%p state=%d flags=%lx", msk, state, msk->flags);
3402 if (state == TCP_LISTEN)
3403 return mptcp_check_readable(msk);
3405 if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) {
3406 mask |= mptcp_check_readable(msk);
3407 mask |= mptcp_check_writeable(msk);
3409 if (sk->sk_shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
3411 if (sk->sk_shutdown & RCV_SHUTDOWN)
3412 mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
3414 /* This barrier is coupled with smp_wmb() in tcp_reset() */
3422 static int mptcp_release(struct socket *sock)
3424 struct mptcp_subflow_context *subflow;
3425 struct sock *sk = sock->sk;
3426 struct mptcp_sock *msk;
3435 mptcp_for_each_subflow(msk, subflow) {
3436 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3438 ip_mc_drop_socket(ssk);
3443 return inet_release(sock);
3446 static const struct proto_ops mptcp_stream_ops = {
3448 .owner = THIS_MODULE,
3449 .release = mptcp_release,
3451 .connect = mptcp_stream_connect,
3452 .socketpair = sock_no_socketpair,
3453 .accept = mptcp_stream_accept,
3454 .getname = inet_getname,
3456 .ioctl = inet_ioctl,
3457 .gettstamp = sock_gettstamp,
3458 .listen = mptcp_listen,
3459 .shutdown = inet_shutdown,
3460 .setsockopt = sock_common_setsockopt,
3461 .getsockopt = sock_common_getsockopt,
3462 .sendmsg = inet_sendmsg,
3463 .recvmsg = inet_recvmsg,
3464 .mmap = sock_no_mmap,
3465 .sendpage = inet_sendpage,
3468 static struct inet_protosw mptcp_protosw = {
3469 .type = SOCK_STREAM,
3470 .protocol = IPPROTO_MPTCP,
3471 .prot = &mptcp_prot,
3472 .ops = &mptcp_stream_ops,
3473 .flags = INET_PROTOSW_ICSK,
3476 static int mptcp_napi_poll(struct napi_struct *napi, int budget)
3478 struct mptcp_delegated_action *delegated;
3479 struct mptcp_subflow_context *subflow;
3482 delegated = container_of(napi, struct mptcp_delegated_action, napi);
3483 while ((subflow = mptcp_subflow_delegated_next(delegated)) != NULL) {
3484 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3486 bh_lock_sock_nested(ssk);
3487 if (!sock_owned_by_user(ssk) &&
3488 mptcp_subflow_has_delegated_action(subflow))
3489 mptcp_subflow_process_delegated(ssk);
3490 /* ... elsewhere tcp_release_cb_override already processed
3491 * the action or will do at next release_sock().
3492 * In both case must dequeue the subflow here - on the same
3493 * CPU that scheduled it.
3495 bh_unlock_sock(ssk);
3498 if (++work_done == budget)
3502 /* always provide a 0 'work_done' argument, so that napi_complete_done
3503 * will not try accessing the NULL napi->dev ptr
3505 napi_complete_done(napi, 0);
3509 void __init mptcp_proto_init(void)
3511 struct mptcp_delegated_action *delegated;
3514 mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo;
3516 if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL))
3517 panic("Failed to allocate MPTCP pcpu counter\n");
3519 init_dummy_netdev(&mptcp_napi_dev);
3520 for_each_possible_cpu(cpu) {
3521 delegated = per_cpu_ptr(&mptcp_delegated_actions, cpu);
3522 INIT_LIST_HEAD(&delegated->head);
3523 netif_tx_napi_add(&mptcp_napi_dev, &delegated->napi, mptcp_napi_poll,
3525 napi_enable(&delegated->napi);
3528 mptcp_subflow_init();
3532 if (proto_register(&mptcp_prot, 1) != 0)
3533 panic("Failed to register MPTCP proto.\n");
3535 inet_register_protosw(&mptcp_protosw);
3537 BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb));
3540 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
3541 static int mptcp6_release(struct socket *sock)
3543 struct mptcp_subflow_context *subflow;
3544 struct mptcp_sock *msk;
3545 struct sock *sk = sock->sk;
3554 mptcp_for_each_subflow(msk, subflow) {
3555 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3557 ip_mc_drop_socket(ssk);
3558 ipv6_sock_mc_close(ssk);
3559 ipv6_sock_ac_close(ssk);
3563 return inet6_release(sock);
3566 static const struct proto_ops mptcp_v6_stream_ops = {
3568 .owner = THIS_MODULE,
3569 .release = mptcp6_release,
3571 .connect = mptcp_stream_connect,
3572 .socketpair = sock_no_socketpair,
3573 .accept = mptcp_stream_accept,
3574 .getname = inet6_getname,
3576 .ioctl = inet6_ioctl,
3577 .gettstamp = sock_gettstamp,
3578 .listen = mptcp_listen,
3579 .shutdown = inet_shutdown,
3580 .setsockopt = sock_common_setsockopt,
3581 .getsockopt = sock_common_getsockopt,
3582 .sendmsg = inet6_sendmsg,
3583 .recvmsg = inet6_recvmsg,
3584 .mmap = sock_no_mmap,
3585 .sendpage = inet_sendpage,
3586 #ifdef CONFIG_COMPAT
3587 .compat_ioctl = inet6_compat_ioctl,
3591 static struct proto mptcp_v6_prot;
3593 static void mptcp_v6_destroy(struct sock *sk)
3596 inet6_destroy_sock(sk);
3599 static struct inet_protosw mptcp_v6_protosw = {
3600 .type = SOCK_STREAM,
3601 .protocol = IPPROTO_MPTCP,
3602 .prot = &mptcp_v6_prot,
3603 .ops = &mptcp_v6_stream_ops,
3604 .flags = INET_PROTOSW_ICSK,
3607 int __init mptcp_proto_v6_init(void)
3611 mptcp_v6_prot = mptcp_prot;
3612 strcpy(mptcp_v6_prot.name, "MPTCPv6");
3613 mptcp_v6_prot.slab = NULL;
3614 mptcp_v6_prot.destroy = mptcp_v6_destroy;
3615 mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock);
3617 err = proto_register(&mptcp_v6_prot, 1);
3621 err = inet6_register_protosw(&mptcp_v6_protosw);
3623 proto_unregister(&mptcp_v6_prot);