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>
15 #include <net/inet_common.h>
16 #include <net/inet_hashtables.h>
17 #include <net/protocol.h>
19 #include <net/tcp_states.h>
20 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
21 #include <net/transp_v6.h>
23 #include <net/mptcp.h>
28 #define CREATE_TRACE_POINTS
29 #include <trace/events/mptcp.h>
31 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
33 struct mptcp_sock msk;
45 #define MPTCP_SKB_CB(__skb) ((struct mptcp_skb_cb *)&((__skb)->cb[0]))
48 MPTCP_CMSG_TS = BIT(0),
51 static struct percpu_counter mptcp_sockets_allocated;
53 static void __mptcp_destroy_sock(struct sock *sk);
54 static void __mptcp_check_send_data_fin(struct sock *sk);
56 DEFINE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
57 static struct net_device mptcp_napi_dev;
59 /* If msk has an initial subflow socket, and the MP_CAPABLE handshake has not
60 * completed yet or has failed, return the subflow socket.
61 * Otherwise return NULL.
63 struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk)
65 if (!msk->subflow || READ_ONCE(msk->can_ack))
71 /* Returns end sequence number of the receiver's advertised window */
72 static u64 mptcp_wnd_end(const struct mptcp_sock *msk)
74 return READ_ONCE(msk->wnd_end);
77 static bool mptcp_is_tcpsk(struct sock *sk)
79 struct socket *sock = sk->sk_socket;
81 if (unlikely(sk->sk_prot == &tcp_prot)) {
82 /* we are being invoked after mptcp_accept() has
83 * accepted a non-mp-capable flow: sk is a tcp_sk,
86 * Hand the socket over to tcp so all further socket ops
89 sock->ops = &inet_stream_ops;
91 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
92 } else if (unlikely(sk->sk_prot == &tcpv6_prot)) {
93 sock->ops = &inet6_stream_ops;
101 static int __mptcp_socket_create(struct mptcp_sock *msk)
103 struct mptcp_subflow_context *subflow;
104 struct sock *sk = (struct sock *)msk;
105 struct socket *ssock;
108 err = mptcp_subflow_create_socket(sk, &ssock);
112 msk->first = ssock->sk;
113 msk->subflow = ssock;
114 subflow = mptcp_subflow_ctx(ssock->sk);
115 list_add(&subflow->node, &msk->conn_list);
116 sock_hold(ssock->sk);
117 subflow->request_mptcp = 1;
118 mptcp_sock_graft(msk->first, sk->sk_socket);
123 static void mptcp_drop(struct sock *sk, struct sk_buff *skb)
125 sk_drops_add(sk, skb);
129 static void mptcp_rmem_charge(struct sock *sk, int size)
131 mptcp_sk(sk)->rmem_fwd_alloc -= size;
134 static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to,
135 struct sk_buff *from)
140 if (MPTCP_SKB_CB(from)->offset ||
141 !skb_try_coalesce(to, from, &fragstolen, &delta))
144 pr_debug("colesced seq %llx into %llx new len %d new end seq %llx",
145 MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq,
146 to->len, MPTCP_SKB_CB(from)->end_seq);
147 MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq;
148 kfree_skb_partial(from, fragstolen);
149 atomic_add(delta, &sk->sk_rmem_alloc);
150 mptcp_rmem_charge(sk, delta);
154 static bool mptcp_ooo_try_coalesce(struct mptcp_sock *msk, struct sk_buff *to,
155 struct sk_buff *from)
157 if (MPTCP_SKB_CB(from)->map_seq != MPTCP_SKB_CB(to)->end_seq)
160 return mptcp_try_coalesce((struct sock *)msk, to, from);
163 static void __mptcp_rmem_reclaim(struct sock *sk, int amount)
165 amount >>= SK_MEM_QUANTUM_SHIFT;
166 mptcp_sk(sk)->rmem_fwd_alloc -= amount << SK_MEM_QUANTUM_SHIFT;
167 __sk_mem_reduce_allocated(sk, amount);
170 static void mptcp_rmem_uncharge(struct sock *sk, int size)
172 struct mptcp_sock *msk = mptcp_sk(sk);
175 msk->rmem_fwd_alloc += size;
176 reclaimable = msk->rmem_fwd_alloc - sk_unused_reserved_mem(sk);
178 /* see sk_mem_uncharge() for the rationale behind the following schema */
179 if (unlikely(reclaimable >= SK_RECLAIM_THRESHOLD))
180 __mptcp_rmem_reclaim(sk, SK_RECLAIM_CHUNK);
183 static void mptcp_rfree(struct sk_buff *skb)
185 unsigned int len = skb->truesize;
186 struct sock *sk = skb->sk;
188 atomic_sub(len, &sk->sk_rmem_alloc);
189 mptcp_rmem_uncharge(sk, len);
192 static void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk)
196 skb->destructor = mptcp_rfree;
197 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
198 mptcp_rmem_charge(sk, skb->truesize);
201 /* "inspired" by tcp_data_queue_ofo(), main differences:
203 * - don't cope with sacks
205 static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb)
207 struct sock *sk = (struct sock *)msk;
208 struct rb_node **p, *parent;
209 u64 seq, end_seq, max_seq;
210 struct sk_buff *skb1;
212 seq = MPTCP_SKB_CB(skb)->map_seq;
213 end_seq = MPTCP_SKB_CB(skb)->end_seq;
214 max_seq = READ_ONCE(msk->rcv_wnd_sent);
216 pr_debug("msk=%p seq=%llx limit=%llx empty=%d", msk, seq, max_seq,
217 RB_EMPTY_ROOT(&msk->out_of_order_queue));
218 if (after64(end_seq, max_seq)) {
221 pr_debug("oow by %lld, rcv_wnd_sent %llu\n",
222 (unsigned long long)end_seq - (unsigned long)max_seq,
223 (unsigned long long)msk->rcv_wnd_sent);
224 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_NODSSWINDOW);
228 p = &msk->out_of_order_queue.rb_node;
229 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUE);
230 if (RB_EMPTY_ROOT(&msk->out_of_order_queue)) {
231 rb_link_node(&skb->rbnode, NULL, p);
232 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
233 msk->ooo_last_skb = skb;
237 /* with 2 subflows, adding at end of ooo queue is quite likely
238 * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup.
240 if (mptcp_ooo_try_coalesce(msk, msk->ooo_last_skb, skb)) {
241 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
242 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
246 /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */
247 if (!before64(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) {
248 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
249 parent = &msk->ooo_last_skb->rbnode;
250 p = &parent->rb_right;
254 /* Find place to insert this segment. Handle overlaps on the way. */
258 skb1 = rb_to_skb(parent);
259 if (before64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
260 p = &parent->rb_left;
263 if (before64(seq, MPTCP_SKB_CB(skb1)->end_seq)) {
264 if (!after64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) {
265 /* All the bits are present. Drop. */
267 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
270 if (after64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
274 * continue traversing
277 /* skb's seq == skb1's seq and skb covers skb1.
278 * Replace skb1 with skb.
280 rb_replace_node(&skb1->rbnode, &skb->rbnode,
281 &msk->out_of_order_queue);
282 mptcp_drop(sk, skb1);
283 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
286 } else if (mptcp_ooo_try_coalesce(msk, skb1, skb)) {
287 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
290 p = &parent->rb_right;
294 /* Insert segment into RB tree. */
295 rb_link_node(&skb->rbnode, parent, p);
296 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
299 /* Remove other segments covered by skb. */
300 while ((skb1 = skb_rb_next(skb)) != NULL) {
301 if (before64(end_seq, MPTCP_SKB_CB(skb1)->end_seq))
303 rb_erase(&skb1->rbnode, &msk->out_of_order_queue);
304 mptcp_drop(sk, skb1);
305 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
307 /* If there is no skb after us, we are the last_skb ! */
309 msk->ooo_last_skb = skb;
313 mptcp_set_owner_r(skb, sk);
316 static bool mptcp_rmem_schedule(struct sock *sk, struct sock *ssk, int size)
318 struct mptcp_sock *msk = mptcp_sk(sk);
321 if (size < msk->rmem_fwd_alloc)
324 amt = sk_mem_pages(size);
325 amount = amt << SK_MEM_QUANTUM_SHIFT;
326 msk->rmem_fwd_alloc += amount;
327 if (!__sk_mem_raise_allocated(sk, size, amt, SK_MEM_RECV)) {
328 if (ssk->sk_forward_alloc < amount) {
329 msk->rmem_fwd_alloc -= amount;
333 ssk->sk_forward_alloc -= amount;
338 static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk,
339 struct sk_buff *skb, unsigned int offset,
342 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
343 struct sock *sk = (struct sock *)msk;
344 struct sk_buff *tail;
347 __skb_unlink(skb, &ssk->sk_receive_queue);
352 /* try to fetch required memory from subflow */
353 if (!mptcp_rmem_schedule(sk, ssk, skb->truesize))
356 has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp;
358 /* the skb map_seq accounts for the skb offset:
359 * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq
362 MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow);
363 MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len;
364 MPTCP_SKB_CB(skb)->offset = offset;
365 MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp;
367 if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) {
369 WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len);
370 tail = skb_peek_tail(&sk->sk_receive_queue);
371 if (tail && mptcp_try_coalesce(sk, tail, skb))
374 mptcp_set_owner_r(skb, sk);
375 __skb_queue_tail(&sk->sk_receive_queue, skb);
377 } else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) {
378 mptcp_data_queue_ofo(msk, skb);
382 /* old data, keep it simple and drop the whole pkt, sender
383 * will retransmit as needed, if needed.
385 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
391 static void mptcp_stop_timer(struct sock *sk)
393 struct inet_connection_sock *icsk = inet_csk(sk);
395 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
396 mptcp_sk(sk)->timer_ival = 0;
399 static void mptcp_close_wake_up(struct sock *sk)
401 if (sock_flag(sk, SOCK_DEAD))
404 sk->sk_state_change(sk);
405 if (sk->sk_shutdown == SHUTDOWN_MASK ||
406 sk->sk_state == TCP_CLOSE)
407 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
409 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
412 static bool mptcp_pending_data_fin_ack(struct sock *sk)
414 struct mptcp_sock *msk = mptcp_sk(sk);
416 return !__mptcp_check_fallback(msk) &&
417 ((1 << sk->sk_state) &
418 (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) &&
419 msk->write_seq == READ_ONCE(msk->snd_una);
422 static void mptcp_check_data_fin_ack(struct sock *sk)
424 struct mptcp_sock *msk = mptcp_sk(sk);
426 /* Look for an acknowledged DATA_FIN */
427 if (mptcp_pending_data_fin_ack(sk)) {
428 WRITE_ONCE(msk->snd_data_fin_enable, 0);
430 switch (sk->sk_state) {
432 inet_sk_state_store(sk, TCP_FIN_WAIT2);
436 inet_sk_state_store(sk, TCP_CLOSE);
440 mptcp_close_wake_up(sk);
444 static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq)
446 struct mptcp_sock *msk = mptcp_sk(sk);
448 if (READ_ONCE(msk->rcv_data_fin) &&
449 ((1 << sk->sk_state) &
450 (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) {
451 u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq);
453 if (msk->ack_seq == rcv_data_fin_seq) {
455 *seq = rcv_data_fin_seq;
464 static void mptcp_set_datafin_timeout(const struct sock *sk)
466 struct inet_connection_sock *icsk = inet_csk(sk);
468 mptcp_sk(sk)->timer_ival = min(TCP_RTO_MAX,
469 TCP_RTO_MIN << icsk->icsk_retransmits);
472 static void __mptcp_set_timeout(struct sock *sk, long tout)
474 mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
477 static long mptcp_timeout_from_subflow(const struct mptcp_subflow_context *subflow)
479 const struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
481 return inet_csk(ssk)->icsk_pending && !subflow->stale_count ?
482 inet_csk(ssk)->icsk_timeout - jiffies : 0;
485 static void mptcp_set_timeout(struct sock *sk)
487 struct mptcp_subflow_context *subflow;
490 mptcp_for_each_subflow(mptcp_sk(sk), subflow)
491 tout = max(tout, mptcp_timeout_from_subflow(subflow));
492 __mptcp_set_timeout(sk, tout);
495 static bool tcp_can_send_ack(const struct sock *ssk)
497 return !((1 << inet_sk_state_load(ssk)) &
498 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE | TCPF_LISTEN));
501 void mptcp_subflow_send_ack(struct sock *ssk)
505 slow = lock_sock_fast(ssk);
506 if (tcp_can_send_ack(ssk))
508 unlock_sock_fast(ssk, slow);
511 static void mptcp_send_ack(struct mptcp_sock *msk)
513 struct mptcp_subflow_context *subflow;
515 mptcp_for_each_subflow(msk, subflow)
516 mptcp_subflow_send_ack(mptcp_subflow_tcp_sock(subflow));
519 static void mptcp_subflow_cleanup_rbuf(struct sock *ssk)
523 slow = lock_sock_fast(ssk);
524 if (tcp_can_send_ack(ssk))
525 tcp_cleanup_rbuf(ssk, 1);
526 unlock_sock_fast(ssk, slow);
529 static bool mptcp_subflow_could_cleanup(const struct sock *ssk, bool rx_empty)
531 const struct inet_connection_sock *icsk = inet_csk(ssk);
532 u8 ack_pending = READ_ONCE(icsk->icsk_ack.pending);
533 const struct tcp_sock *tp = tcp_sk(ssk);
535 return (ack_pending & ICSK_ACK_SCHED) &&
536 ((READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->rcv_wup) >
537 READ_ONCE(icsk->icsk_ack.rcv_mss)) ||
538 (rx_empty && ack_pending &
539 (ICSK_ACK_PUSHED2 | ICSK_ACK_PUSHED)));
542 static void mptcp_cleanup_rbuf(struct mptcp_sock *msk)
544 int old_space = READ_ONCE(msk->old_wspace);
545 struct mptcp_subflow_context *subflow;
546 struct sock *sk = (struct sock *)msk;
547 int space = __mptcp_space(sk);
548 bool cleanup, rx_empty;
550 cleanup = (space > 0) && (space >= (old_space << 1));
551 rx_empty = !__mptcp_rmem(sk);
553 mptcp_for_each_subflow(msk, subflow) {
554 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
556 if (cleanup || mptcp_subflow_could_cleanup(ssk, rx_empty))
557 mptcp_subflow_cleanup_rbuf(ssk);
561 static bool mptcp_check_data_fin(struct sock *sk)
563 struct mptcp_sock *msk = mptcp_sk(sk);
564 u64 rcv_data_fin_seq;
567 if (__mptcp_check_fallback(msk))
570 /* Need to ack a DATA_FIN received from a peer while this side
571 * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2.
572 * msk->rcv_data_fin was set when parsing the incoming options
573 * at the subflow level and the msk lock was not held, so this
574 * is the first opportunity to act on the DATA_FIN and change
577 * If we are caught up to the sequence number of the incoming
578 * DATA_FIN, send the DATA_ACK now and do state transition. If
579 * not caught up, do nothing and let the recv code send DATA_ACK
583 if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) {
584 WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1);
585 WRITE_ONCE(msk->rcv_data_fin, 0);
587 sk->sk_shutdown |= RCV_SHUTDOWN;
588 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
590 switch (sk->sk_state) {
591 case TCP_ESTABLISHED:
592 inet_sk_state_store(sk, TCP_CLOSE_WAIT);
595 inet_sk_state_store(sk, TCP_CLOSING);
598 inet_sk_state_store(sk, TCP_CLOSE);
601 /* Other states not expected */
608 mptcp_close_wake_up(sk);
613 static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
617 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
618 struct sock *sk = (struct sock *)msk;
619 unsigned int moved = 0;
620 bool more_data_avail;
625 sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
627 if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
628 int ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
630 if (unlikely(ssk_rbuf > sk_rbuf)) {
631 WRITE_ONCE(sk->sk_rcvbuf, ssk_rbuf);
636 pr_debug("msk=%p ssk=%p", msk, ssk);
639 u32 map_remaining, offset;
640 u32 seq = tp->copied_seq;
644 /* try to move as much data as available */
645 map_remaining = subflow->map_data_len -
646 mptcp_subflow_get_map_offset(subflow);
648 skb = skb_peek(&ssk->sk_receive_queue);
650 /* if no data is found, a racing workqueue/recvmsg
651 * already processed the new data, stop here or we
652 * can enter an infinite loop
659 if (__mptcp_check_fallback(msk)) {
660 /* if we are running under the workqueue, TCP could have
661 * collapsed skbs between dummy map creation and now
662 * be sure to adjust the size
664 map_remaining = skb->len;
665 subflow->map_data_len = skb->len;
668 offset = seq - TCP_SKB_CB(skb)->seq;
669 fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
675 if (offset < skb->len) {
676 size_t len = skb->len - offset;
681 if (__mptcp_move_skb(msk, ssk, skb, offset, len))
685 if (WARN_ON_ONCE(map_remaining < len))
689 sk_eat_skb(ssk, skb);
693 WRITE_ONCE(tp->copied_seq, seq);
694 more_data_avail = mptcp_subflow_data_available(ssk);
696 if (atomic_read(&sk->sk_rmem_alloc) > sk_rbuf) {
700 } while (more_data_avail);
706 static bool __mptcp_ofo_queue(struct mptcp_sock *msk)
708 struct sock *sk = (struct sock *)msk;
709 struct sk_buff *skb, *tail;
714 p = rb_first(&msk->out_of_order_queue);
715 pr_debug("msk=%p empty=%d", msk, RB_EMPTY_ROOT(&msk->out_of_order_queue));
718 if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq))
722 rb_erase(&skb->rbnode, &msk->out_of_order_queue);
724 if (unlikely(!after64(MPTCP_SKB_CB(skb)->end_seq,
727 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
731 end_seq = MPTCP_SKB_CB(skb)->end_seq;
732 tail = skb_peek_tail(&sk->sk_receive_queue);
733 if (!tail || !mptcp_ooo_try_coalesce(msk, tail, skb)) {
734 int delta = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq;
736 /* skip overlapping data, if any */
737 pr_debug("uncoalesced seq=%llx ack seq=%llx delta=%d",
738 MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq,
740 MPTCP_SKB_CB(skb)->offset += delta;
741 __skb_queue_tail(&sk->sk_receive_queue, skb);
743 msk->ack_seq = end_seq;
749 /* In most cases we will be able to lock the mptcp socket. If its already
750 * owned, we need to defer to the work queue to avoid ABBA deadlock.
752 static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk)
754 struct sock *sk = (struct sock *)msk;
755 unsigned int moved = 0;
757 __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
758 __mptcp_ofo_queue(msk);
759 if (unlikely(ssk->sk_err)) {
760 if (!sock_owned_by_user(sk))
761 __mptcp_error_report(sk);
763 set_bit(MPTCP_ERROR_REPORT, &msk->flags);
766 /* If the moves have caught up with the DATA_FIN sequence number
767 * it's time to ack the DATA_FIN and change socket state, but
768 * this is not a good place to change state. Let the workqueue
771 if (mptcp_pending_data_fin(sk, NULL))
772 mptcp_schedule_work(sk);
776 void mptcp_data_ready(struct sock *sk, struct sock *ssk)
778 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
779 struct mptcp_sock *msk = mptcp_sk(sk);
780 int sk_rbuf, ssk_rbuf;
782 /* The peer can send data while we are shutting down this
783 * subflow at msk destruction time, but we must avoid enqueuing
784 * more data to the msk receive queue
786 if (unlikely(subflow->disposable))
789 ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
790 sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
791 if (unlikely(ssk_rbuf > sk_rbuf))
794 /* over limit? can't append more skbs to msk, Also, no need to wake-up*/
795 if (__mptcp_rmem(sk) > sk_rbuf) {
796 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED);
800 /* Wake-up the reader only for in-sequence data */
802 if (move_skbs_to_msk(msk, ssk))
803 sk->sk_data_ready(sk);
805 mptcp_data_unlock(sk);
808 static bool mptcp_do_flush_join_list(struct mptcp_sock *msk)
810 struct mptcp_subflow_context *subflow;
813 if (likely(list_empty(&msk->join_list)))
816 spin_lock_bh(&msk->join_list_lock);
817 list_for_each_entry(subflow, &msk->join_list, node) {
818 u32 sseq = READ_ONCE(subflow->setsockopt_seq);
820 mptcp_propagate_sndbuf((struct sock *)msk, mptcp_subflow_tcp_sock(subflow));
821 if (READ_ONCE(msk->setsockopt_seq) != sseq)
824 list_splice_tail_init(&msk->join_list, &msk->conn_list);
825 spin_unlock_bh(&msk->join_list_lock);
830 void __mptcp_flush_join_list(struct mptcp_sock *msk)
832 if (likely(!mptcp_do_flush_join_list(msk)))
835 if (!test_and_set_bit(MPTCP_WORK_SYNC_SETSOCKOPT, &msk->flags))
836 mptcp_schedule_work((struct sock *)msk);
839 static void mptcp_flush_join_list(struct mptcp_sock *msk)
841 bool sync_needed = test_and_clear_bit(MPTCP_WORK_SYNC_SETSOCKOPT, &msk->flags);
845 if (!mptcp_do_flush_join_list(msk) && !sync_needed)
848 mptcp_sockopt_sync_all(msk);
851 static bool mptcp_timer_pending(struct sock *sk)
853 return timer_pending(&inet_csk(sk)->icsk_retransmit_timer);
856 static void mptcp_reset_timer(struct sock *sk)
858 struct inet_connection_sock *icsk = inet_csk(sk);
861 /* prevent rescheduling on close */
862 if (unlikely(inet_sk_state_load(sk) == TCP_CLOSE))
865 tout = mptcp_sk(sk)->timer_ival;
866 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout);
869 bool mptcp_schedule_work(struct sock *sk)
871 if (inet_sk_state_load(sk) != TCP_CLOSE &&
872 schedule_work(&mptcp_sk(sk)->work)) {
873 /* each subflow already holds a reference to the sk, and the
874 * workqueue is invoked by a subflow, so sk can't go away here.
882 void mptcp_subflow_eof(struct sock *sk)
884 if (!test_and_set_bit(MPTCP_WORK_EOF, &mptcp_sk(sk)->flags))
885 mptcp_schedule_work(sk);
888 static void mptcp_check_for_eof(struct mptcp_sock *msk)
890 struct mptcp_subflow_context *subflow;
891 struct sock *sk = (struct sock *)msk;
894 mptcp_for_each_subflow(msk, subflow)
895 receivers += !subflow->rx_eof;
899 if (!(sk->sk_shutdown & RCV_SHUTDOWN)) {
900 /* hopefully temporary hack: propagate shutdown status
901 * to msk, when all subflows agree on it
903 sk->sk_shutdown |= RCV_SHUTDOWN;
905 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
906 sk->sk_data_ready(sk);
909 switch (sk->sk_state) {
910 case TCP_ESTABLISHED:
911 inet_sk_state_store(sk, TCP_CLOSE_WAIT);
914 inet_sk_state_store(sk, TCP_CLOSING);
917 inet_sk_state_store(sk, TCP_CLOSE);
922 mptcp_close_wake_up(sk);
925 static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk)
927 struct mptcp_subflow_context *subflow;
928 struct sock *sk = (struct sock *)msk;
930 sock_owned_by_me(sk);
932 mptcp_for_each_subflow(msk, subflow) {
933 if (READ_ONCE(subflow->data_avail))
934 return mptcp_subflow_tcp_sock(subflow);
940 static bool mptcp_skb_can_collapse_to(u64 write_seq,
941 const struct sk_buff *skb,
942 const struct mptcp_ext *mpext)
944 if (!tcp_skb_can_collapse_to(skb))
947 /* can collapse only if MPTCP level sequence is in order and this
948 * mapping has not been xmitted yet
950 return mpext && mpext->data_seq + mpext->data_len == write_seq &&
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
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)
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;
969 static void __mptcp_mem_reclaim_partial(struct sock *sk)
971 int reclaimable = mptcp_sk(sk)->rmem_fwd_alloc - sk_unused_reserved_mem(sk);
973 lockdep_assert_held_once(&sk->sk_lock.slock);
975 __mptcp_rmem_reclaim(sk, reclaimable - 1);
976 sk_mem_reclaim_partial(sk);
979 static void mptcp_mem_reclaim_partial(struct sock *sk)
982 __mptcp_mem_reclaim_partial(sk);
983 mptcp_data_unlock(sk);
986 static void dfrag_uncharge(struct sock *sk, int len)
988 sk_mem_uncharge(sk, len);
989 sk_wmem_queued_add(sk, -len);
992 static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag)
994 int len = dfrag->data_len + dfrag->overhead;
996 list_del(&dfrag->list);
997 dfrag_uncharge(sk, len);
998 put_page(dfrag->page);
1001 static void __mptcp_clean_una(struct sock *sk)
1003 struct mptcp_sock *msk = mptcp_sk(sk);
1004 struct mptcp_data_frag *dtmp, *dfrag;
1005 bool cleaned = false;
1008 /* on fallback we just need to ignore snd_una, as this is really
1011 if (__mptcp_check_fallback(msk))
1012 msk->snd_una = READ_ONCE(msk->snd_nxt);
1014 snd_una = msk->snd_una;
1015 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) {
1016 if (after64(dfrag->data_seq + dfrag->data_len, snd_una))
1019 if (unlikely(dfrag == msk->first_pending)) {
1020 /* in recovery mode can see ack after the current snd head */
1021 if (WARN_ON_ONCE(!msk->recovery))
1024 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1027 dfrag_clear(sk, dfrag);
1031 dfrag = mptcp_rtx_head(sk);
1032 if (dfrag && after64(snd_una, dfrag->data_seq)) {
1033 u64 delta = snd_una - dfrag->data_seq;
1035 /* prevent wrap around in recovery mode */
1036 if (unlikely(delta > dfrag->already_sent)) {
1037 if (WARN_ON_ONCE(!msk->recovery))
1039 if (WARN_ON_ONCE(delta > dfrag->data_len))
1041 dfrag->already_sent += delta - dfrag->already_sent;
1044 dfrag->data_seq += delta;
1045 dfrag->offset += delta;
1046 dfrag->data_len -= delta;
1047 dfrag->already_sent -= delta;
1049 dfrag_uncharge(sk, delta);
1053 /* all retransmitted data acked, recovery completed */
1054 if (unlikely(msk->recovery) && after64(msk->snd_una, msk->recovery_snd_nxt))
1055 msk->recovery = false;
1058 if (cleaned && tcp_under_memory_pressure(sk))
1059 __mptcp_mem_reclaim_partial(sk);
1061 if (snd_una == READ_ONCE(msk->snd_nxt) &&
1062 snd_una == READ_ONCE(msk->write_seq)) {
1063 if (mptcp_timer_pending(sk) && !mptcp_data_fin_enabled(msk))
1064 mptcp_stop_timer(sk);
1066 mptcp_reset_timer(sk);
1070 static void __mptcp_clean_una_wakeup(struct sock *sk)
1072 lockdep_assert_held_once(&sk->sk_lock.slock);
1074 __mptcp_clean_una(sk);
1075 mptcp_write_space(sk);
1078 static void mptcp_clean_una_wakeup(struct sock *sk)
1080 mptcp_data_lock(sk);
1081 __mptcp_clean_una_wakeup(sk);
1082 mptcp_data_unlock(sk);
1085 static void mptcp_enter_memory_pressure(struct sock *sk)
1087 struct mptcp_subflow_context *subflow;
1088 struct mptcp_sock *msk = mptcp_sk(sk);
1091 sk_stream_moderate_sndbuf(sk);
1092 mptcp_for_each_subflow(msk, subflow) {
1093 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
1096 tcp_enter_memory_pressure(ssk);
1097 sk_stream_moderate_sndbuf(ssk);
1102 /* ensure we get enough memory for the frag hdr, beyond some minimal amount of
1105 static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag)
1107 if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag),
1108 pfrag, sk->sk_allocation)))
1111 mptcp_enter_memory_pressure(sk);
1115 static struct mptcp_data_frag *
1116 mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag,
1119 int offset = ALIGN(orig_offset, sizeof(long));
1120 struct mptcp_data_frag *dfrag;
1122 dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset);
1123 dfrag->data_len = 0;
1124 dfrag->data_seq = msk->write_seq;
1125 dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag);
1126 dfrag->offset = offset + sizeof(struct mptcp_data_frag);
1127 dfrag->already_sent = 0;
1128 dfrag->page = pfrag->page;
1133 struct mptcp_sendmsg_info {
1139 bool data_lock_held;
1142 static int mptcp_check_allowed_size(struct mptcp_sock *msk, u64 data_seq,
1145 u64 window_end = mptcp_wnd_end(msk);
1147 if (__mptcp_check_fallback(msk))
1150 if (!before64(data_seq + avail_size, window_end)) {
1151 u64 allowed_size = window_end - data_seq;
1153 return min_t(unsigned int, allowed_size, avail_size);
1159 static bool __mptcp_add_ext(struct sk_buff *skb, gfp_t gfp)
1161 struct skb_ext *mpext = __skb_ext_alloc(gfp);
1165 __skb_ext_set(skb, SKB_EXT_MPTCP, mpext);
1169 static struct sk_buff *__mptcp_do_alloc_tx_skb(struct sock *sk, gfp_t gfp)
1171 struct sk_buff *skb;
1173 skb = alloc_skb_fclone(MAX_TCP_HEADER, gfp);
1175 if (likely(__mptcp_add_ext(skb, gfp))) {
1176 skb_reserve(skb, MAX_TCP_HEADER);
1177 skb->ip_summed = CHECKSUM_PARTIAL;
1178 INIT_LIST_HEAD(&skb->tcp_tsorted_anchor);
1183 mptcp_enter_memory_pressure(sk);
1188 static struct sk_buff *__mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, gfp_t gfp)
1190 struct sk_buff *skb;
1192 skb = __mptcp_do_alloc_tx_skb(sk, gfp);
1196 if (likely(sk_wmem_schedule(ssk, skb->truesize))) {
1197 tcp_skb_entail(ssk, skb);
1204 static struct sk_buff *mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, bool data_lock_held)
1206 gfp_t gfp = data_lock_held ? GFP_ATOMIC : sk->sk_allocation;
1208 if (unlikely(tcp_under_memory_pressure(sk))) {
1210 __mptcp_mem_reclaim_partial(sk);
1212 mptcp_mem_reclaim_partial(sk);
1214 return __mptcp_alloc_tx_skb(sk, ssk, gfp);
1217 /* note: this always recompute the csum on the whole skb, even
1218 * if we just appended a single frag. More status info needed
1220 static void mptcp_update_data_checksum(struct sk_buff *skb, int added)
1222 struct mptcp_ext *mpext = mptcp_get_ext(skb);
1223 __wsum csum = ~csum_unfold(mpext->csum);
1224 int offset = skb->len - added;
1226 mpext->csum = csum_fold(csum_block_add(csum, skb_checksum(skb, offset, added, 0), offset));
1229 static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
1230 struct mptcp_data_frag *dfrag,
1231 struct mptcp_sendmsg_info *info)
1233 u64 data_seq = dfrag->data_seq + info->sent;
1234 int offset = dfrag->offset + info->sent;
1235 struct mptcp_sock *msk = mptcp_sk(sk);
1236 bool zero_window_probe = false;
1237 struct mptcp_ext *mpext = NULL;
1238 bool can_coalesce = false;
1239 bool reuse_skb = true;
1240 struct sk_buff *skb;
1244 pr_debug("msk=%p ssk=%p sending dfrag at seq=%llu len=%u already sent=%u",
1245 msk, ssk, dfrag->data_seq, dfrag->data_len, info->sent);
1247 if (WARN_ON_ONCE(info->sent > info->limit ||
1248 info->limit > dfrag->data_len))
1251 /* compute send limit */
1252 info->mss_now = tcp_send_mss(ssk, &info->size_goal, info->flags);
1253 copy = info->size_goal;
1255 skb = tcp_write_queue_tail(ssk);
1256 if (skb && copy > skb->len) {
1257 /* Limit the write to the size available in the
1258 * current skb, if any, so that we create at most a new skb.
1259 * Explicitly tells TCP internals to avoid collapsing on later
1260 * queue management operation, to avoid breaking the ext <->
1261 * SSN association set here
1263 mpext = skb_ext_find(skb, SKB_EXT_MPTCP);
1264 if (!mptcp_skb_can_collapse_to(data_seq, skb, mpext)) {
1265 TCP_SKB_CB(skb)->eor = 1;
1269 i = skb_shinfo(skb)->nr_frags;
1270 can_coalesce = skb_can_coalesce(skb, i, dfrag->page, offset);
1271 if (!can_coalesce && i >= sysctl_max_skb_frags) {
1272 tcp_mark_push(tcp_sk(ssk), skb);
1279 skb = mptcp_alloc_tx_skb(sk, ssk, info->data_lock_held);
1283 i = skb_shinfo(skb)->nr_frags;
1285 mpext = skb_ext_find(skb, SKB_EXT_MPTCP);
1288 /* Zero window and all data acked? Probe. */
1289 copy = mptcp_check_allowed_size(msk, data_seq, copy);
1291 u64 snd_una = READ_ONCE(msk->snd_una);
1293 if (snd_una != msk->snd_nxt) {
1294 tcp_remove_empty_skb(ssk);
1298 zero_window_probe = true;
1299 data_seq = snd_una - 1;
1302 /* all mptcp-level data is acked, no skbs should be present into the
1305 WARN_ON_ONCE(reuse_skb);
1308 copy = min_t(size_t, copy, info->limit - info->sent);
1309 if (!sk_wmem_schedule(ssk, copy)) {
1310 tcp_remove_empty_skb(ssk);
1315 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1317 get_page(dfrag->page);
1318 skb_fill_page_desc(skb, i, dfrag->page, offset, copy);
1322 skb->data_len += copy;
1323 skb->truesize += copy;
1324 sk_wmem_queued_add(ssk, copy);
1325 sk_mem_charge(ssk, copy);
1326 WRITE_ONCE(tcp_sk(ssk)->write_seq, tcp_sk(ssk)->write_seq + copy);
1327 TCP_SKB_CB(skb)->end_seq += copy;
1328 tcp_skb_pcount_set(skb, 0);
1330 /* on skb reuse we just need to update the DSS len */
1332 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1333 mpext->data_len += copy;
1334 WARN_ON_ONCE(zero_window_probe);
1338 memset(mpext, 0, sizeof(*mpext));
1339 mpext->data_seq = data_seq;
1340 mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq;
1341 mpext->data_len = copy;
1345 pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d",
1346 mpext->data_seq, mpext->subflow_seq, mpext->data_len,
1349 if (zero_window_probe) {
1350 mptcp_subflow_ctx(ssk)->rel_write_seq += copy;
1352 if (READ_ONCE(msk->csum_enabled))
1353 mptcp_update_data_checksum(skb, copy);
1354 tcp_push_pending_frames(ssk);
1358 if (READ_ONCE(msk->csum_enabled))
1359 mptcp_update_data_checksum(skb, copy);
1360 mptcp_subflow_ctx(ssk)->rel_write_seq += copy;
1364 #define MPTCP_SEND_BURST_SIZE ((1 << 16) - \
1365 sizeof(struct tcphdr) - \
1366 MAX_TCP_OPTION_SPACE - \
1367 sizeof(struct ipv6hdr) - \
1368 sizeof(struct frag_hdr))
1370 struct subflow_send_info {
1375 void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow)
1377 if (!subflow->stale)
1381 MPTCP_INC_STATS(sock_net(mptcp_subflow_tcp_sock(subflow)), MPTCP_MIB_SUBFLOWRECOVER);
1384 bool mptcp_subflow_active(struct mptcp_subflow_context *subflow)
1386 if (unlikely(subflow->stale)) {
1387 u32 rcv_tstamp = READ_ONCE(tcp_sk(mptcp_subflow_tcp_sock(subflow))->rcv_tstamp);
1389 if (subflow->stale_rcv_tstamp == rcv_tstamp)
1392 mptcp_subflow_set_active(subflow);
1394 return __mptcp_subflow_active(subflow);
1397 /* implement the mptcp packet scheduler;
1398 * returns the subflow that will transmit the next DSS
1399 * additionally updates the rtx timeout
1401 static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk)
1403 struct subflow_send_info send_info[2];
1404 struct mptcp_subflow_context *subflow;
1405 struct sock *sk = (struct sock *)msk;
1406 int i, nr_active = 0;
1412 sock_owned_by_me(sk);
1414 if (__mptcp_check_fallback(msk)) {
1417 return sk_stream_memory_free(msk->first) ? msk->first : NULL;
1420 /* re-use last subflow, if the burst allow that */
1421 if (msk->last_snd && msk->snd_burst > 0 &&
1422 sk_stream_memory_free(msk->last_snd) &&
1423 mptcp_subflow_active(mptcp_subflow_ctx(msk->last_snd))) {
1424 mptcp_set_timeout(sk);
1425 return msk->last_snd;
1428 /* pick the subflow with the lower wmem/wspace ratio */
1429 for (i = 0; i < 2; ++i) {
1430 send_info[i].ssk = NULL;
1431 send_info[i].ratio = -1;
1433 mptcp_for_each_subflow(msk, subflow) {
1434 trace_mptcp_subflow_get_send(subflow);
1435 ssk = mptcp_subflow_tcp_sock(subflow);
1436 if (!mptcp_subflow_active(subflow))
1439 tout = max(tout, mptcp_timeout_from_subflow(subflow));
1440 nr_active += !subflow->backup;
1441 if (!sk_stream_memory_free(subflow->tcp_sock) || !tcp_sk(ssk)->snd_wnd)
1444 pace = READ_ONCE(ssk->sk_pacing_rate);
1448 ratio = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32,
1450 if (ratio < send_info[subflow->backup].ratio) {
1451 send_info[subflow->backup].ssk = ssk;
1452 send_info[subflow->backup].ratio = ratio;
1455 __mptcp_set_timeout(sk, tout);
1457 /* pick the best backup if no other subflow is active */
1459 send_info[0].ssk = send_info[1].ssk;
1461 if (send_info[0].ssk) {
1462 msk->last_snd = send_info[0].ssk;
1463 msk->snd_burst = min_t(int, MPTCP_SEND_BURST_SIZE,
1464 tcp_sk(msk->last_snd)->snd_wnd);
1465 return msk->last_snd;
1471 static void mptcp_push_release(struct sock *ssk, struct mptcp_sendmsg_info *info)
1473 tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal);
1477 static void mptcp_update_post_push(struct mptcp_sock *msk,
1478 struct mptcp_data_frag *dfrag,
1481 u64 snd_nxt_new = dfrag->data_seq;
1483 dfrag->already_sent += sent;
1485 msk->snd_burst -= sent;
1487 snd_nxt_new += dfrag->already_sent;
1489 /* snd_nxt_new can be smaller than snd_nxt in case mptcp
1490 * is recovering after a failover. In that event, this re-sends
1493 * Thus compute snd_nxt_new candidate based on
1494 * the dfrag->data_seq that was sent and the data
1495 * that has been handed to the subflow for transmission
1496 * and skip update in case it was old dfrag.
1498 if (likely(after64(snd_nxt_new, msk->snd_nxt)))
1499 msk->snd_nxt = snd_nxt_new;
1502 static void mptcp_check_and_set_pending(struct sock *sk)
1504 if (mptcp_send_head(sk) &&
1505 !test_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags))
1506 set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags);
1509 void __mptcp_push_pending(struct sock *sk, unsigned int flags)
1511 struct sock *prev_ssk = NULL, *ssk = NULL;
1512 struct mptcp_sock *msk = mptcp_sk(sk);
1513 struct mptcp_sendmsg_info info = {
1516 struct mptcp_data_frag *dfrag;
1517 int len, copied = 0;
1519 while ((dfrag = mptcp_send_head(sk))) {
1520 info.sent = dfrag->already_sent;
1521 info.limit = dfrag->data_len;
1522 len = dfrag->data_len - dfrag->already_sent;
1527 mptcp_flush_join_list(msk);
1528 ssk = mptcp_subflow_get_send(msk);
1530 /* First check. If the ssk has changed since
1531 * the last round, release prev_ssk
1533 if (ssk != prev_ssk && prev_ssk)
1534 mptcp_push_release(prev_ssk, &info);
1538 /* Need to lock the new subflow only if different
1539 * from the previous one, otherwise we are still
1540 * helding the relevant lock
1542 if (ssk != prev_ssk)
1545 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
1547 mptcp_push_release(ssk, &info);
1555 mptcp_update_post_push(msk, dfrag, ret);
1557 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1560 /* at this point we held the socket lock for the last subflow we used */
1562 mptcp_push_release(ssk, &info);
1565 /* ensure the rtx timer is running */
1566 if (!mptcp_timer_pending(sk))
1567 mptcp_reset_timer(sk);
1569 __mptcp_check_send_data_fin(sk);
1572 static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk)
1574 struct mptcp_sock *msk = mptcp_sk(sk);
1575 struct mptcp_sendmsg_info info = {
1576 .data_lock_held = true,
1578 struct mptcp_data_frag *dfrag;
1579 struct sock *xmit_ssk;
1580 int len, copied = 0;
1584 while ((dfrag = mptcp_send_head(sk))) {
1585 info.sent = dfrag->already_sent;
1586 info.limit = dfrag->data_len;
1587 len = dfrag->data_len - dfrag->already_sent;
1591 /* the caller already invoked the packet scheduler,
1592 * check for a different subflow usage only after
1593 * spooling the first chunk of data
1595 xmit_ssk = first ? ssk : mptcp_subflow_get_send(mptcp_sk(sk));
1598 if (xmit_ssk != ssk) {
1599 mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk));
1603 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
1612 mptcp_update_post_push(msk, dfrag, ret);
1614 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1618 /* __mptcp_alloc_tx_skb could have released some wmem and we are
1619 * not going to flush it via release_sock()
1622 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
1624 if (!mptcp_timer_pending(sk))
1625 mptcp_reset_timer(sk);
1627 if (msk->snd_data_fin_enable &&
1628 msk->snd_nxt + 1 == msk->write_seq)
1629 mptcp_schedule_work(sk);
1633 static void mptcp_set_nospace(struct sock *sk)
1635 /* enable autotune */
1636 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1638 /* will be cleared on avail space */
1639 set_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags);
1642 static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
1644 struct mptcp_sock *msk = mptcp_sk(sk);
1645 struct page_frag *pfrag;
1650 /* we don't support FASTOPEN yet */
1651 if (msg->msg_flags & MSG_FASTOPEN)
1654 /* silently ignore everything else */
1655 msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL;
1659 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1661 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
1662 ret = sk_stream_wait_connect(sk, &timeo);
1667 pfrag = sk_page_frag(sk);
1669 while (msg_data_left(msg)) {
1670 int total_ts, frag_truesize = 0;
1671 struct mptcp_data_frag *dfrag;
1672 bool dfrag_collapsed;
1673 size_t psize, offset;
1675 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) {
1680 /* reuse tail pfrag, if possible, or carve a new one from the
1683 dfrag = mptcp_pending_tail(sk);
1684 dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag);
1685 if (!dfrag_collapsed) {
1686 if (!sk_stream_memory_free(sk))
1687 goto wait_for_memory;
1689 if (!mptcp_page_frag_refill(sk, pfrag))
1690 goto wait_for_memory;
1692 dfrag = mptcp_carve_data_frag(msk, pfrag, pfrag->offset);
1693 frag_truesize = dfrag->overhead;
1696 /* we do not bound vs wspace, to allow a single packet.
1697 * memory accounting will prevent execessive memory usage
1700 offset = dfrag->offset + dfrag->data_len;
1701 psize = pfrag->size - offset;
1702 psize = min_t(size_t, psize, msg_data_left(msg));
1703 total_ts = psize + frag_truesize;
1705 if (!sk_wmem_schedule(sk, total_ts))
1706 goto wait_for_memory;
1708 if (copy_page_from_iter(dfrag->page, offset, psize,
1709 &msg->msg_iter) != psize) {
1714 /* data successfully copied into the write queue */
1715 sk->sk_forward_alloc -= total_ts;
1717 dfrag->data_len += psize;
1718 frag_truesize += psize;
1719 pfrag->offset += frag_truesize;
1720 WRITE_ONCE(msk->write_seq, msk->write_seq + psize);
1722 /* charge data on mptcp pending queue to the msk socket
1723 * Note: we charge such data both to sk and ssk
1725 sk_wmem_queued_add(sk, frag_truesize);
1726 if (!dfrag_collapsed) {
1727 get_page(dfrag->page);
1728 list_add_tail(&dfrag->list, &msk->rtx_queue);
1729 if (!msk->first_pending)
1730 WRITE_ONCE(msk->first_pending, dfrag);
1732 pr_debug("msk=%p dfrag at seq=%llu len=%u sent=%u new=%d", msk,
1733 dfrag->data_seq, dfrag->data_len, dfrag->already_sent,
1739 mptcp_set_nospace(sk);
1740 __mptcp_push_pending(sk, msg->msg_flags);
1741 ret = sk_stream_wait_memory(sk, &timeo);
1747 __mptcp_push_pending(sk, msg->msg_flags);
1751 return copied ? : ret;
1754 static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk,
1756 size_t len, int flags,
1757 struct scm_timestamping_internal *tss,
1760 struct sk_buff *skb, *tmp;
1763 skb_queue_walk_safe(&msk->receive_queue, skb, tmp) {
1764 u32 offset = MPTCP_SKB_CB(skb)->offset;
1765 u32 data_len = skb->len - offset;
1766 u32 count = min_t(size_t, len - copied, data_len);
1769 if (!(flags & MSG_TRUNC)) {
1770 err = skb_copy_datagram_msg(skb, offset, msg, count);
1771 if (unlikely(err < 0)) {
1778 if (MPTCP_SKB_CB(skb)->has_rxtstamp) {
1779 tcp_update_recv_tstamps(skb, tss);
1780 *cmsg_flags |= MPTCP_CMSG_TS;
1785 if (count < data_len) {
1786 if (!(flags & MSG_PEEK))
1787 MPTCP_SKB_CB(skb)->offset += count;
1791 if (!(flags & MSG_PEEK)) {
1792 /* we will bulk release the skb memory later */
1793 skb->destructor = NULL;
1794 WRITE_ONCE(msk->rmem_released, msk->rmem_released + skb->truesize);
1795 __skb_unlink(skb, &msk->receive_queue);
1806 /* receive buffer autotuning. See tcp_rcv_space_adjust for more information.
1808 * Only difference: Use highest rtt estimate of the subflows in use.
1810 static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied)
1812 struct mptcp_subflow_context *subflow;
1813 struct sock *sk = (struct sock *)msk;
1814 u32 time, advmss = 1;
1817 sock_owned_by_me(sk);
1822 msk->rcvq_space.copied += copied;
1824 mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC);
1825 time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time);
1827 rtt_us = msk->rcvq_space.rtt_us;
1828 if (rtt_us && time < (rtt_us >> 3))
1832 mptcp_for_each_subflow(msk, subflow) {
1833 const struct tcp_sock *tp;
1837 tp = tcp_sk(mptcp_subflow_tcp_sock(subflow));
1839 sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us);
1840 sf_advmss = READ_ONCE(tp->advmss);
1842 rtt_us = max(sf_rtt_us, rtt_us);
1843 advmss = max(sf_advmss, advmss);
1846 msk->rcvq_space.rtt_us = rtt_us;
1847 if (time < (rtt_us >> 3) || rtt_us == 0)
1850 if (msk->rcvq_space.copied <= msk->rcvq_space.space)
1853 if (sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf &&
1854 !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
1858 rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss;
1860 grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space);
1862 do_div(grow, msk->rcvq_space.space);
1863 rcvwin += (grow << 1);
1865 rcvmem = SKB_TRUESIZE(advmss + MAX_TCP_HEADER);
1866 while (tcp_win_from_space(sk, rcvmem) < advmss)
1869 do_div(rcvwin, advmss);
1870 rcvbuf = min_t(u64, rcvwin * rcvmem,
1871 sock_net(sk)->ipv4.sysctl_tcp_rmem[2]);
1873 if (rcvbuf > sk->sk_rcvbuf) {
1876 window_clamp = tcp_win_from_space(sk, rcvbuf);
1877 WRITE_ONCE(sk->sk_rcvbuf, rcvbuf);
1879 /* Make subflows follow along. If we do not do this, we
1880 * get drops at subflow level if skbs can't be moved to
1881 * the mptcp rx queue fast enough (announced rcv_win can
1882 * exceed ssk->sk_rcvbuf).
1884 mptcp_for_each_subflow(msk, subflow) {
1888 ssk = mptcp_subflow_tcp_sock(subflow);
1889 slow = lock_sock_fast(ssk);
1890 WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf);
1891 tcp_sk(ssk)->window_clamp = window_clamp;
1892 tcp_cleanup_rbuf(ssk, 1);
1893 unlock_sock_fast(ssk, slow);
1898 msk->rcvq_space.space = msk->rcvq_space.copied;
1900 msk->rcvq_space.copied = 0;
1901 msk->rcvq_space.time = mstamp;
1904 static void __mptcp_update_rmem(struct sock *sk)
1906 struct mptcp_sock *msk = mptcp_sk(sk);
1908 if (!msk->rmem_released)
1911 atomic_sub(msk->rmem_released, &sk->sk_rmem_alloc);
1912 mptcp_rmem_uncharge(sk, msk->rmem_released);
1913 WRITE_ONCE(msk->rmem_released, 0);
1916 static void __mptcp_splice_receive_queue(struct sock *sk)
1918 struct mptcp_sock *msk = mptcp_sk(sk);
1920 skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue);
1923 static bool __mptcp_move_skbs(struct mptcp_sock *msk)
1925 struct sock *sk = (struct sock *)msk;
1926 unsigned int moved = 0;
1929 mptcp_flush_join_list(msk);
1931 struct sock *ssk = mptcp_subflow_recv_lookup(msk);
1934 /* we can have data pending in the subflows only if the msk
1935 * receive buffer was full at subflow_data_ready() time,
1936 * that is an unlikely slow path.
1941 slowpath = lock_sock_fast(ssk);
1942 mptcp_data_lock(sk);
1943 __mptcp_update_rmem(sk);
1944 done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
1945 mptcp_data_unlock(sk);
1947 if (unlikely(ssk->sk_err))
1948 __mptcp_error_report(sk);
1949 unlock_sock_fast(ssk, slowpath);
1952 /* acquire the data lock only if some input data is pending */
1954 if (!RB_EMPTY_ROOT(&msk->out_of_order_queue) ||
1955 !skb_queue_empty_lockless(&sk->sk_receive_queue)) {
1956 mptcp_data_lock(sk);
1957 __mptcp_update_rmem(sk);
1958 ret |= __mptcp_ofo_queue(msk);
1959 __mptcp_splice_receive_queue(sk);
1960 mptcp_data_unlock(sk);
1963 mptcp_check_data_fin((struct sock *)msk);
1964 return !skb_queue_empty(&msk->receive_queue);
1967 static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
1968 int nonblock, int flags, int *addr_len)
1970 struct mptcp_sock *msk = mptcp_sk(sk);
1971 struct scm_timestamping_internal tss;
1972 int copied = 0, cmsg_flags = 0;
1976 /* MSG_ERRQUEUE is really a no-op till we support IP_RECVERR */
1977 if (unlikely(flags & MSG_ERRQUEUE))
1978 return inet_recv_error(sk, msg, len, addr_len);
1981 if (unlikely(sk->sk_state == TCP_LISTEN)) {
1986 timeo = sock_rcvtimeo(sk, nonblock);
1988 len = min_t(size_t, len, INT_MAX);
1989 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1991 while (copied < len) {
1994 bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags, &tss, &cmsg_flags);
1995 if (unlikely(bytes_read < 0)) {
1997 copied = bytes_read;
2001 copied += bytes_read;
2003 /* be sure to advertise window change */
2004 mptcp_cleanup_rbuf(msk);
2006 if (skb_queue_empty(&msk->receive_queue) && __mptcp_move_skbs(msk))
2009 /* only the master socket status is relevant here. The exit
2010 * conditions mirror closely tcp_recvmsg()
2012 if (copied >= target)
2017 sk->sk_state == TCP_CLOSE ||
2018 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2020 signal_pending(current))
2024 copied = sock_error(sk);
2028 if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
2029 mptcp_check_for_eof(msk);
2031 if (sk->sk_shutdown & RCV_SHUTDOWN) {
2032 /* race breaker: the shutdown could be after the
2033 * previous receive queue check
2035 if (__mptcp_move_skbs(msk))
2040 if (sk->sk_state == TCP_CLOSE) {
2050 if (signal_pending(current)) {
2051 copied = sock_intr_errno(timeo);
2056 pr_debug("block timeout %ld", timeo);
2057 sk_wait_data(sk, &timeo, NULL);
2061 if (cmsg_flags && copied >= 0) {
2062 if (cmsg_flags & MPTCP_CMSG_TS)
2063 tcp_recv_timestamp(msg, sk, &tss);
2066 pr_debug("msk=%p rx queue empty=%d:%d copied=%d",
2067 msk, skb_queue_empty_lockless(&sk->sk_receive_queue),
2068 skb_queue_empty(&msk->receive_queue), copied);
2069 if (!(flags & MSG_PEEK))
2070 mptcp_rcv_space_adjust(msk, copied);
2076 static void mptcp_retransmit_timer(struct timer_list *t)
2078 struct inet_connection_sock *icsk = from_timer(icsk, t,
2079 icsk_retransmit_timer);
2080 struct sock *sk = &icsk->icsk_inet.sk;
2081 struct mptcp_sock *msk = mptcp_sk(sk);
2084 if (!sock_owned_by_user(sk)) {
2085 /* we need a process context to retransmit */
2086 if (!test_and_set_bit(MPTCP_WORK_RTX, &msk->flags))
2087 mptcp_schedule_work(sk);
2089 /* delegate our work to tcp_release_cb() */
2090 set_bit(MPTCP_RETRANSMIT, &msk->flags);
2096 static void mptcp_timeout_timer(struct timer_list *t)
2098 struct sock *sk = from_timer(sk, t, sk_timer);
2100 mptcp_schedule_work(sk);
2104 /* Find an idle subflow. Return NULL if there is unacked data at tcp
2107 * A backup subflow is returned only if that is the only kind available.
2109 static struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk)
2111 struct sock *backup = NULL, *pick = NULL;
2112 struct mptcp_subflow_context *subflow;
2113 int min_stale_count = INT_MAX;
2115 sock_owned_by_me((const struct sock *)msk);
2117 if (__mptcp_check_fallback(msk))
2120 mptcp_for_each_subflow(msk, subflow) {
2121 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2123 if (!__mptcp_subflow_active(subflow))
2126 /* still data outstanding at TCP level? skip this */
2127 if (!tcp_rtx_and_write_queues_empty(ssk)) {
2128 mptcp_pm_subflow_chk_stale(msk, ssk);
2129 min_stale_count = min_t(int, min_stale_count, subflow->stale_count);
2133 if (subflow->backup) {
2146 /* use backup only if there are no progresses anywhere */
2147 return min_stale_count > 1 ? backup : NULL;
2150 static void mptcp_dispose_initial_subflow(struct mptcp_sock *msk)
2153 iput(SOCK_INODE(msk->subflow));
2154 msk->subflow = NULL;
2158 bool __mptcp_retransmit_pending_data(struct sock *sk)
2160 struct mptcp_data_frag *cur, *rtx_head;
2161 struct mptcp_sock *msk = mptcp_sk(sk);
2163 if (__mptcp_check_fallback(mptcp_sk(sk)))
2166 if (tcp_rtx_and_write_queues_empty(sk))
2169 /* the closing socket has some data untransmitted and/or unacked:
2170 * some data in the mptcp rtx queue has not really xmitted yet.
2171 * keep it simple and re-inject the whole mptcp level rtx queue
2173 mptcp_data_lock(sk);
2174 __mptcp_clean_una_wakeup(sk);
2175 rtx_head = mptcp_rtx_head(sk);
2177 mptcp_data_unlock(sk);
2181 msk->recovery_snd_nxt = msk->snd_nxt;
2182 msk->recovery = true;
2183 mptcp_data_unlock(sk);
2185 msk->first_pending = rtx_head;
2188 /* be sure to clear the "sent status" on all re-injected fragments */
2189 list_for_each_entry(cur, &msk->rtx_queue, list) {
2190 if (!cur->already_sent)
2192 cur->already_sent = 0;
2198 /* subflow sockets can be either outgoing (connect) or incoming
2201 * Outgoing subflows use in-kernel sockets.
2202 * Incoming subflows do not have their own 'struct socket' allocated,
2203 * so we need to use tcp_close() after detaching them from the mptcp
2206 static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
2207 struct mptcp_subflow_context *subflow)
2209 struct mptcp_sock *msk = mptcp_sk(sk);
2212 list_del(&subflow->node);
2214 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
2216 /* if we are invoked by the msk cleanup code, the subflow is
2222 need_push = __mptcp_retransmit_pending_data(sk);
2223 subflow->disposable = 1;
2225 /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops
2226 * the ssk has been already destroyed, we just need to release the
2227 * reference owned by msk;
2229 if (!inet_csk(ssk)->icsk_ulp_ops) {
2230 kfree_rcu(subflow, rcu);
2232 /* otherwise tcp will dispose of the ssk and subflow ctx */
2233 __tcp_close(ssk, 0);
2235 /* close acquired an extra ref */
2242 if (ssk == msk->last_snd)
2243 msk->last_snd = NULL;
2245 if (ssk == msk->first)
2248 if (msk->subflow && ssk == msk->subflow->sk)
2249 mptcp_dispose_initial_subflow(msk);
2252 __mptcp_push_pending(sk, 0);
2255 void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
2256 struct mptcp_subflow_context *subflow)
2258 if (sk->sk_state == TCP_ESTABLISHED)
2259 mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL);
2260 __mptcp_close_ssk(sk, ssk, subflow);
2263 static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu)
2268 static void __mptcp_close_subflow(struct mptcp_sock *msk)
2270 struct mptcp_subflow_context *subflow, *tmp;
2274 list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
2275 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2277 if (inet_sk_state_load(ssk) != TCP_CLOSE)
2280 /* 'subflow_data_ready' will re-sched once rx queue is empty */
2281 if (!skb_queue_empty_lockless(&ssk->sk_receive_queue))
2284 mptcp_close_ssk((struct sock *)msk, ssk, subflow);
2288 static bool mptcp_check_close_timeout(const struct sock *sk)
2290 s32 delta = tcp_jiffies32 - inet_csk(sk)->icsk_mtup.probe_timestamp;
2291 struct mptcp_subflow_context *subflow;
2293 if (delta >= TCP_TIMEWAIT_LEN)
2296 /* if all subflows are in closed status don't bother with additional
2299 mptcp_for_each_subflow(mptcp_sk(sk), subflow) {
2300 if (inet_sk_state_load(mptcp_subflow_tcp_sock(subflow)) !=
2307 static void mptcp_check_fastclose(struct mptcp_sock *msk)
2309 struct mptcp_subflow_context *subflow, *tmp;
2310 struct sock *sk = &msk->sk.icsk_inet.sk;
2312 if (likely(!READ_ONCE(msk->rcv_fastclose)))
2315 mptcp_token_destroy(msk);
2317 list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
2318 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
2321 slow = lock_sock_fast(tcp_sk);
2322 if (tcp_sk->sk_state != TCP_CLOSE) {
2323 tcp_send_active_reset(tcp_sk, GFP_ATOMIC);
2324 tcp_set_state(tcp_sk, TCP_CLOSE);
2326 unlock_sock_fast(tcp_sk, slow);
2329 inet_sk_state_store(sk, TCP_CLOSE);
2330 sk->sk_shutdown = SHUTDOWN_MASK;
2331 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
2332 set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags);
2334 mptcp_close_wake_up(sk);
2337 static void __mptcp_retrans(struct sock *sk)
2339 struct mptcp_sock *msk = mptcp_sk(sk);
2340 struct mptcp_sendmsg_info info = {};
2341 struct mptcp_data_frag *dfrag;
2346 mptcp_clean_una_wakeup(sk);
2348 /* first check ssk: need to kick "stale" logic */
2349 ssk = mptcp_subflow_get_retrans(msk);
2350 dfrag = mptcp_rtx_head(sk);
2352 if (mptcp_data_fin_enabled(msk)) {
2353 struct inet_connection_sock *icsk = inet_csk(sk);
2355 icsk->icsk_retransmits++;
2356 mptcp_set_datafin_timeout(sk);
2357 mptcp_send_ack(msk);
2362 if (!mptcp_send_head(sk))
2373 /* limit retransmission to the bytes already sent on some subflows */
2375 info.limit = READ_ONCE(msk->csum_enabled) ? dfrag->data_len : dfrag->already_sent;
2376 while (info.sent < info.limit) {
2377 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
2381 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS);
2386 dfrag->already_sent = max(dfrag->already_sent, info.sent);
2387 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
2394 mptcp_check_and_set_pending(sk);
2396 if (!mptcp_timer_pending(sk))
2397 mptcp_reset_timer(sk);
2400 static void mptcp_worker(struct work_struct *work)
2402 struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
2403 struct sock *sk = &msk->sk.icsk_inet.sk;
2407 state = sk->sk_state;
2408 if (unlikely(state == TCP_CLOSE))
2411 mptcp_check_data_fin_ack(sk);
2412 mptcp_flush_join_list(msk);
2414 mptcp_check_fastclose(msk);
2417 mptcp_pm_nl_work(msk);
2419 if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
2420 mptcp_check_for_eof(msk);
2422 __mptcp_check_send_data_fin(sk);
2423 mptcp_check_data_fin(sk);
2425 /* There is no point in keeping around an orphaned sk timedout or
2426 * closed, but we need the msk around to reply to incoming DATA_FIN,
2427 * even if it is orphaned and in FIN_WAIT2 state
2429 if (sock_flag(sk, SOCK_DEAD) &&
2430 (mptcp_check_close_timeout(sk) || sk->sk_state == TCP_CLOSE)) {
2431 inet_sk_state_store(sk, TCP_CLOSE);
2432 __mptcp_destroy_sock(sk);
2436 if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
2437 __mptcp_close_subflow(msk);
2439 if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
2440 __mptcp_retrans(sk);
2447 static int __mptcp_init_sock(struct sock *sk)
2449 struct mptcp_sock *msk = mptcp_sk(sk);
2451 spin_lock_init(&msk->join_list_lock);
2453 INIT_LIST_HEAD(&msk->conn_list);
2454 INIT_LIST_HEAD(&msk->join_list);
2455 INIT_LIST_HEAD(&msk->rtx_queue);
2456 INIT_WORK(&msk->work, mptcp_worker);
2457 __skb_queue_head_init(&msk->receive_queue);
2458 msk->out_of_order_queue = RB_ROOT;
2459 msk->first_pending = NULL;
2460 msk->rmem_fwd_alloc = 0;
2461 WRITE_ONCE(msk->rmem_released, 0);
2462 msk->timer_ival = TCP_RTO_MIN;
2465 inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss;
2466 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
2467 msk->recovery = false;
2469 mptcp_pm_data_init(msk);
2471 /* re-use the csk retrans timer for MPTCP-level retrans */
2472 timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0);
2473 timer_setup(&sk->sk_timer, mptcp_timeout_timer, 0);
2478 static int mptcp_init_sock(struct sock *sk)
2480 struct inet_connection_sock *icsk = inet_csk(sk);
2481 struct net *net = sock_net(sk);
2484 ret = __mptcp_init_sock(sk);
2488 if (!mptcp_is_enabled(net))
2489 return -ENOPROTOOPT;
2491 if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net))
2494 ret = __mptcp_socket_create(mptcp_sk(sk));
2498 /* fetch the ca name; do it outside __mptcp_init_sock(), so that clone will
2499 * propagate the correct value
2501 tcp_assign_congestion_control(sk);
2502 strcpy(mptcp_sk(sk)->ca_name, icsk->icsk_ca_ops->name);
2504 /* no need to keep a reference to the ops, the name will suffice */
2505 tcp_cleanup_congestion_control(sk);
2506 icsk->icsk_ca_ops = NULL;
2508 sk_sockets_allocated_inc(sk);
2509 sk->sk_rcvbuf = sock_net(sk)->ipv4.sysctl_tcp_rmem[1];
2510 sk->sk_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[1];
2515 static void __mptcp_clear_xmit(struct sock *sk)
2517 struct mptcp_sock *msk = mptcp_sk(sk);
2518 struct mptcp_data_frag *dtmp, *dfrag;
2520 WRITE_ONCE(msk->first_pending, NULL);
2521 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list)
2522 dfrag_clear(sk, dfrag);
2525 static void mptcp_cancel_work(struct sock *sk)
2527 struct mptcp_sock *msk = mptcp_sk(sk);
2529 if (cancel_work_sync(&msk->work))
2533 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how)
2537 switch (ssk->sk_state) {
2539 if (!(how & RCV_SHUTDOWN))
2543 tcp_disconnect(ssk, O_NONBLOCK);
2546 if (__mptcp_check_fallback(mptcp_sk(sk))) {
2547 pr_debug("Fallback");
2548 ssk->sk_shutdown |= how;
2549 tcp_shutdown(ssk, how);
2551 pr_debug("Sending DATA_FIN on subflow %p", ssk);
2553 if (!mptcp_timer_pending(sk))
2554 mptcp_reset_timer(sk);
2562 static const unsigned char new_state[16] = {
2563 /* current state: new state: action: */
2564 [0 /* (Invalid) */] = TCP_CLOSE,
2565 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2566 [TCP_SYN_SENT] = TCP_CLOSE,
2567 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2568 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1,
2569 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2,
2570 [TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */
2571 [TCP_CLOSE] = TCP_CLOSE,
2572 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN,
2573 [TCP_LAST_ACK] = TCP_LAST_ACK,
2574 [TCP_LISTEN] = TCP_CLOSE,
2575 [TCP_CLOSING] = TCP_CLOSING,
2576 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */
2579 static int mptcp_close_state(struct sock *sk)
2581 int next = (int)new_state[sk->sk_state];
2582 int ns = next & TCP_STATE_MASK;
2584 inet_sk_state_store(sk, ns);
2586 return next & TCP_ACTION_FIN;
2589 static void __mptcp_check_send_data_fin(struct sock *sk)
2591 struct mptcp_subflow_context *subflow;
2592 struct mptcp_sock *msk = mptcp_sk(sk);
2594 pr_debug("msk=%p snd_data_fin_enable=%d pending=%d snd_nxt=%llu write_seq=%llu",
2595 msk, msk->snd_data_fin_enable, !!mptcp_send_head(sk),
2596 msk->snd_nxt, msk->write_seq);
2598 /* we still need to enqueue subflows or not really shutting down,
2601 if (!msk->snd_data_fin_enable || msk->snd_nxt + 1 != msk->write_seq ||
2602 mptcp_send_head(sk))
2605 WRITE_ONCE(msk->snd_nxt, msk->write_seq);
2607 /* fallback socket will not get data_fin/ack, can move to the next
2610 if (__mptcp_check_fallback(msk)) {
2611 if ((1 << sk->sk_state) & (TCPF_CLOSING | TCPF_LAST_ACK)) {
2612 inet_sk_state_store(sk, TCP_CLOSE);
2613 mptcp_close_wake_up(sk);
2614 } else if (sk->sk_state == TCP_FIN_WAIT1) {
2615 inet_sk_state_store(sk, TCP_FIN_WAIT2);
2619 mptcp_flush_join_list(msk);
2620 mptcp_for_each_subflow(msk, subflow) {
2621 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
2623 mptcp_subflow_shutdown(sk, tcp_sk, SEND_SHUTDOWN);
2627 static void __mptcp_wr_shutdown(struct sock *sk)
2629 struct mptcp_sock *msk = mptcp_sk(sk);
2631 pr_debug("msk=%p snd_data_fin_enable=%d shutdown=%x state=%d pending=%d",
2632 msk, msk->snd_data_fin_enable, sk->sk_shutdown, sk->sk_state,
2633 !!mptcp_send_head(sk));
2635 /* will be ignored by fallback sockets */
2636 WRITE_ONCE(msk->write_seq, msk->write_seq + 1);
2637 WRITE_ONCE(msk->snd_data_fin_enable, 1);
2639 __mptcp_check_send_data_fin(sk);
2642 static void __mptcp_destroy_sock(struct sock *sk)
2644 struct mptcp_subflow_context *subflow, *tmp;
2645 struct mptcp_sock *msk = mptcp_sk(sk);
2646 LIST_HEAD(conn_list);
2648 pr_debug("msk=%p", msk);
2652 /* be sure to always acquire the join list lock, to sync vs
2653 * mptcp_finish_join().
2655 spin_lock_bh(&msk->join_list_lock);
2656 list_splice_tail_init(&msk->join_list, &msk->conn_list);
2657 spin_unlock_bh(&msk->join_list_lock);
2658 list_splice_init(&msk->conn_list, &conn_list);
2660 sk_stop_timer(sk, &msk->sk.icsk_retransmit_timer);
2661 sk_stop_timer(sk, &sk->sk_timer);
2664 list_for_each_entry_safe(subflow, tmp, &conn_list, node) {
2665 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2666 __mptcp_close_ssk(sk, ssk, subflow);
2669 sk->sk_prot->destroy(sk);
2671 WARN_ON_ONCE(msk->rmem_fwd_alloc);
2672 WARN_ON_ONCE(msk->rmem_released);
2673 sk_stream_kill_queues(sk);
2674 xfrm_sk_free_policy(sk);
2676 sk_refcnt_debug_release(sk);
2677 mptcp_dispose_initial_subflow(msk);
2681 static void mptcp_close(struct sock *sk, long timeout)
2683 struct mptcp_subflow_context *subflow;
2684 bool do_cancel_work = false;
2687 sk->sk_shutdown = SHUTDOWN_MASK;
2689 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) {
2690 inet_sk_state_store(sk, TCP_CLOSE);
2694 if (mptcp_close_state(sk))
2695 __mptcp_wr_shutdown(sk);
2697 sk_stream_wait_close(sk, timeout);
2700 /* orphan all the subflows */
2701 inet_csk(sk)->icsk_mtup.probe_timestamp = tcp_jiffies32;
2702 mptcp_for_each_subflow(mptcp_sk(sk), subflow) {
2703 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2704 bool slow = lock_sock_fast_nested(ssk);
2707 unlock_sock_fast(ssk, slow);
2712 pr_debug("msk=%p state=%d", sk, sk->sk_state);
2713 if (sk->sk_state == TCP_CLOSE) {
2714 __mptcp_destroy_sock(sk);
2715 do_cancel_work = true;
2717 sk_reset_timer(sk, &sk->sk_timer, jiffies + TCP_TIMEWAIT_LEN);
2721 mptcp_cancel_work(sk);
2723 if (mptcp_sk(sk)->token)
2724 mptcp_event(MPTCP_EVENT_CLOSED, mptcp_sk(sk), NULL, GFP_KERNEL);
2729 static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk)
2731 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
2732 const struct ipv6_pinfo *ssk6 = inet6_sk(ssk);
2733 struct ipv6_pinfo *msk6 = inet6_sk(msk);
2735 msk->sk_v6_daddr = ssk->sk_v6_daddr;
2736 msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr;
2739 msk6->saddr = ssk6->saddr;
2740 msk6->flow_label = ssk6->flow_label;
2744 inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num;
2745 inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport;
2746 inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport;
2747 inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr;
2748 inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr;
2749 inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr;
2752 static int mptcp_disconnect(struct sock *sk, int flags)
2754 struct mptcp_subflow_context *subflow;
2755 struct mptcp_sock *msk = mptcp_sk(sk);
2757 mptcp_do_flush_join_list(msk);
2759 mptcp_for_each_subflow(msk, subflow) {
2760 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2763 tcp_disconnect(ssk, flags);
2769 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
2770 static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk)
2772 unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo);
2774 return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
2778 struct sock *mptcp_sk_clone(const struct sock *sk,
2779 const struct mptcp_options_received *mp_opt,
2780 struct request_sock *req)
2782 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
2783 struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC);
2784 struct mptcp_sock *msk;
2790 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
2791 if (nsk->sk_family == AF_INET6)
2792 inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk);
2795 __mptcp_init_sock(nsk);
2797 msk = mptcp_sk(nsk);
2798 msk->local_key = subflow_req->local_key;
2799 msk->token = subflow_req->token;
2800 msk->subflow = NULL;
2801 WRITE_ONCE(msk->fully_established, false);
2802 if (mp_opt->suboptions & OPTION_MPTCP_CSUMREQD)
2803 WRITE_ONCE(msk->csum_enabled, true);
2805 msk->write_seq = subflow_req->idsn + 1;
2806 msk->snd_nxt = msk->write_seq;
2807 msk->snd_una = msk->write_seq;
2808 msk->wnd_end = msk->snd_nxt + req->rsk_rcv_wnd;
2809 msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq;
2811 if (mp_opt->suboptions & OPTIONS_MPTCP_MPC) {
2812 msk->can_ack = true;
2813 msk->remote_key = mp_opt->sndr_key;
2814 mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq);
2816 WRITE_ONCE(msk->ack_seq, ack_seq);
2817 WRITE_ONCE(msk->rcv_wnd_sent, ack_seq);
2820 sock_reset_flag(nsk, SOCK_RCU_FREE);
2821 /* will be fully established after successful MPC subflow creation */
2822 inet_sk_state_store(nsk, TCP_SYN_RECV);
2824 security_inet_csk_clone(nsk, req);
2825 bh_unlock_sock(nsk);
2827 /* keep a single reference */
2832 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk)
2834 const struct tcp_sock *tp = tcp_sk(ssk);
2836 msk->rcvq_space.copied = 0;
2837 msk->rcvq_space.rtt_us = 0;
2839 msk->rcvq_space.time = tp->tcp_mstamp;
2841 /* initial rcv_space offering made to peer */
2842 msk->rcvq_space.space = min_t(u32, tp->rcv_wnd,
2843 TCP_INIT_CWND * tp->advmss);
2844 if (msk->rcvq_space.space == 0)
2845 msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT;
2847 WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd);
2850 static struct sock *mptcp_accept(struct sock *sk, int flags, int *err,
2853 struct mptcp_sock *msk = mptcp_sk(sk);
2854 struct socket *listener;
2857 listener = __mptcp_nmpc_socket(msk);
2858 if (WARN_ON_ONCE(!listener)) {
2863 pr_debug("msk=%p, listener=%p", msk, mptcp_subflow_ctx(listener->sk));
2864 newsk = inet_csk_accept(listener->sk, flags, err, kern);
2868 pr_debug("msk=%p, subflow is mptcp=%d", msk, sk_is_mptcp(newsk));
2869 if (sk_is_mptcp(newsk)) {
2870 struct mptcp_subflow_context *subflow;
2871 struct sock *new_mptcp_sock;
2873 subflow = mptcp_subflow_ctx(newsk);
2874 new_mptcp_sock = subflow->conn;
2876 /* is_mptcp should be false if subflow->conn is missing, see
2877 * subflow_syn_recv_sock()
2879 if (WARN_ON_ONCE(!new_mptcp_sock)) {
2880 tcp_sk(newsk)->is_mptcp = 0;
2884 /* acquire the 2nd reference for the owning socket */
2885 sock_hold(new_mptcp_sock);
2886 newsk = new_mptcp_sock;
2887 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEPASSIVEACK);
2889 MPTCP_INC_STATS(sock_net(sk),
2890 MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK);
2896 void mptcp_destroy_common(struct mptcp_sock *msk)
2898 struct sock *sk = (struct sock *)msk;
2900 __mptcp_clear_xmit(sk);
2902 /* move to sk_receive_queue, sk_stream_kill_queues will purge it */
2903 skb_queue_splice_tail_init(&msk->receive_queue, &sk->sk_receive_queue);
2904 __skb_queue_purge(&sk->sk_receive_queue);
2905 skb_rbtree_purge(&msk->out_of_order_queue);
2907 /* move all the rx fwd alloc into the sk_mem_reclaim_final in
2908 * inet_sock_destruct() will dispose it
2910 sk->sk_forward_alloc += msk->rmem_fwd_alloc;
2911 msk->rmem_fwd_alloc = 0;
2912 mptcp_token_destroy(msk);
2913 mptcp_pm_free_anno_list(msk);
2916 static void mptcp_destroy(struct sock *sk)
2918 struct mptcp_sock *msk = mptcp_sk(sk);
2920 mptcp_destroy_common(msk);
2921 sk_sockets_allocated_dec(sk);
2924 void __mptcp_data_acked(struct sock *sk)
2926 if (!sock_owned_by_user(sk))
2927 __mptcp_clean_una(sk);
2929 set_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->flags);
2931 if (mptcp_pending_data_fin_ack(sk))
2932 mptcp_schedule_work(sk);
2935 void __mptcp_check_push(struct sock *sk, struct sock *ssk)
2937 if (!mptcp_send_head(sk))
2940 if (!sock_owned_by_user(sk)) {
2941 struct sock *xmit_ssk = mptcp_subflow_get_send(mptcp_sk(sk));
2943 if (xmit_ssk == ssk)
2944 __mptcp_subflow_push_pending(sk, ssk);
2946 mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk));
2948 set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags);
2952 /* processes deferred events and flush wmem */
2953 static void mptcp_release_cb(struct sock *sk)
2956 unsigned long flags = 0;
2958 if (test_and_clear_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags))
2959 flags |= BIT(MPTCP_PUSH_PENDING);
2960 if (test_and_clear_bit(MPTCP_RETRANSMIT, &mptcp_sk(sk)->flags))
2961 flags |= BIT(MPTCP_RETRANSMIT);
2965 /* the following actions acquire the subflow socket lock
2967 * 1) can't be invoked in atomic scope
2968 * 2) must avoid ABBA deadlock with msk socket spinlock: the RX
2969 * datapath acquires the msk socket spinlock while helding
2970 * the subflow socket lock
2973 spin_unlock_bh(&sk->sk_lock.slock);
2974 if (flags & BIT(MPTCP_PUSH_PENDING))
2975 __mptcp_push_pending(sk, 0);
2976 if (flags & BIT(MPTCP_RETRANSMIT))
2977 __mptcp_retrans(sk);
2980 spin_lock_bh(&sk->sk_lock.slock);
2983 /* be sure to set the current sk state before tacking actions
2984 * depending on sk_state
2986 if (test_and_clear_bit(MPTCP_CONNECTED, &mptcp_sk(sk)->flags))
2987 __mptcp_set_connected(sk);
2988 if (test_and_clear_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->flags))
2989 __mptcp_clean_una_wakeup(sk);
2990 if (test_and_clear_bit(MPTCP_ERROR_REPORT, &mptcp_sk(sk)->flags))
2991 __mptcp_error_report(sk);
2993 __mptcp_update_rmem(sk);
2996 void mptcp_subflow_process_delegated(struct sock *ssk)
2998 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
2999 struct sock *sk = subflow->conn;
3001 mptcp_data_lock(sk);
3002 if (!sock_owned_by_user(sk))
3003 __mptcp_subflow_push_pending(sk, ssk);
3005 set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags);
3006 mptcp_data_unlock(sk);
3007 mptcp_subflow_delegated_done(subflow);
3010 static int mptcp_hash(struct sock *sk)
3012 /* should never be called,
3013 * we hash the TCP subflows not the master socket
3019 static void mptcp_unhash(struct sock *sk)
3021 /* called from sk_common_release(), but nothing to do here */
3024 static int mptcp_get_port(struct sock *sk, unsigned short snum)
3026 struct mptcp_sock *msk = mptcp_sk(sk);
3027 struct socket *ssock;
3029 ssock = __mptcp_nmpc_socket(msk);
3030 pr_debug("msk=%p, subflow=%p", msk, ssock);
3031 if (WARN_ON_ONCE(!ssock))
3034 return inet_csk_get_port(ssock->sk, snum);
3037 void mptcp_finish_connect(struct sock *ssk)
3039 struct mptcp_subflow_context *subflow;
3040 struct mptcp_sock *msk;
3044 subflow = mptcp_subflow_ctx(ssk);
3048 pr_debug("msk=%p, token=%u", sk, subflow->token);
3050 mptcp_crypto_key_sha(subflow->remote_key, NULL, &ack_seq);
3052 subflow->map_seq = ack_seq;
3053 subflow->map_subflow_seq = 1;
3055 /* the socket is not connected yet, no msk/subflow ops can access/race
3056 * accessing the field below
3058 WRITE_ONCE(msk->remote_key, subflow->remote_key);
3059 WRITE_ONCE(msk->local_key, subflow->local_key);
3060 WRITE_ONCE(msk->write_seq, subflow->idsn + 1);
3061 WRITE_ONCE(msk->snd_nxt, msk->write_seq);
3062 WRITE_ONCE(msk->ack_seq, ack_seq);
3063 WRITE_ONCE(msk->rcv_wnd_sent, ack_seq);
3064 WRITE_ONCE(msk->can_ack, 1);
3065 WRITE_ONCE(msk->snd_una, msk->write_seq);
3067 mptcp_pm_new_connection(msk, ssk, 0);
3069 mptcp_rcv_space_init(msk, ssk);
3072 void mptcp_sock_graft(struct sock *sk, struct socket *parent)
3074 write_lock_bh(&sk->sk_callback_lock);
3075 rcu_assign_pointer(sk->sk_wq, &parent->wq);
3076 sk_set_socket(sk, parent);
3077 sk->sk_uid = SOCK_INODE(parent)->i_uid;
3078 write_unlock_bh(&sk->sk_callback_lock);
3081 bool mptcp_finish_join(struct sock *ssk)
3083 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
3084 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
3085 struct sock *parent = (void *)msk;
3086 struct socket *parent_sock;
3089 pr_debug("msk=%p, subflow=%p", msk, subflow);
3091 /* mptcp socket already closing? */
3092 if (!mptcp_is_fully_established(parent)) {
3093 subflow->reset_reason = MPTCP_RST_EMPTCP;
3097 if (!msk->pm.server_side)
3100 if (!mptcp_pm_allow_new_subflow(msk)) {
3101 subflow->reset_reason = MPTCP_RST_EPROHIBIT;
3105 /* active connections are already on conn_list, and we can't acquire
3107 * use the join list lock as synchronization point and double-check
3108 * msk status to avoid racing with __mptcp_destroy_sock()
3110 spin_lock_bh(&msk->join_list_lock);
3111 ret = inet_sk_state_load(parent) == TCP_ESTABLISHED;
3112 if (ret && !WARN_ON_ONCE(!list_empty(&subflow->node))) {
3113 list_add_tail(&subflow->node, &msk->join_list);
3116 spin_unlock_bh(&msk->join_list_lock);
3118 subflow->reset_reason = MPTCP_RST_EPROHIBIT;
3122 /* attach to msk socket only after we are sure he will deal with us
3125 parent_sock = READ_ONCE(parent->sk_socket);
3126 if (parent_sock && !ssk->sk_socket)
3127 mptcp_sock_graft(ssk, parent_sock);
3128 subflow->map_seq = READ_ONCE(msk->ack_seq);
3130 mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC);
3134 static void mptcp_shutdown(struct sock *sk, int how)
3136 pr_debug("sk=%p, how=%d", sk, how);
3138 if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk))
3139 __mptcp_wr_shutdown(sk);
3142 static int mptcp_forward_alloc_get(const struct sock *sk)
3144 return sk->sk_forward_alloc + mptcp_sk(sk)->rmem_fwd_alloc;
3147 static struct proto mptcp_prot = {
3149 .owner = THIS_MODULE,
3150 .init = mptcp_init_sock,
3151 .disconnect = mptcp_disconnect,
3152 .close = mptcp_close,
3153 .accept = mptcp_accept,
3154 .setsockopt = mptcp_setsockopt,
3155 .getsockopt = mptcp_getsockopt,
3156 .shutdown = mptcp_shutdown,
3157 .destroy = mptcp_destroy,
3158 .sendmsg = mptcp_sendmsg,
3159 .recvmsg = mptcp_recvmsg,
3160 .release_cb = mptcp_release_cb,
3162 .unhash = mptcp_unhash,
3163 .get_port = mptcp_get_port,
3164 .forward_alloc_get = mptcp_forward_alloc_get,
3165 .sockets_allocated = &mptcp_sockets_allocated,
3166 .memory_allocated = &tcp_memory_allocated,
3167 .memory_pressure = &tcp_memory_pressure,
3168 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
3169 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
3170 .sysctl_mem = sysctl_tcp_mem,
3171 .obj_size = sizeof(struct mptcp_sock),
3172 .slab_flags = SLAB_TYPESAFE_BY_RCU,
3173 .no_autobind = true,
3176 static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
3178 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3179 struct socket *ssock;
3182 lock_sock(sock->sk);
3183 ssock = __mptcp_nmpc_socket(msk);
3189 err = ssock->ops->bind(ssock, uaddr, addr_len);
3191 mptcp_copy_inaddrs(sock->sk, ssock->sk);
3194 release_sock(sock->sk);
3198 static void mptcp_subflow_early_fallback(struct mptcp_sock *msk,
3199 struct mptcp_subflow_context *subflow)
3201 subflow->request_mptcp = 0;
3202 __mptcp_do_fallback(msk);
3205 static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
3206 int addr_len, int flags)
3208 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3209 struct mptcp_subflow_context *subflow;
3210 struct socket *ssock;
3213 lock_sock(sock->sk);
3214 if (sock->state != SS_UNCONNECTED && msk->subflow) {
3215 /* pending connection or invalid state, let existing subflow
3218 ssock = msk->subflow;
3222 ssock = __mptcp_nmpc_socket(msk);
3228 mptcp_token_destroy(msk);
3229 inet_sk_state_store(sock->sk, TCP_SYN_SENT);
3230 subflow = mptcp_subflow_ctx(ssock->sk);
3231 #ifdef CONFIG_TCP_MD5SIG
3232 /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
3235 if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info))
3236 mptcp_subflow_early_fallback(msk, subflow);
3238 if (subflow->request_mptcp && mptcp_token_new_connect(ssock->sk)) {
3239 MPTCP_INC_STATS(sock_net(ssock->sk), MPTCP_MIB_TOKENFALLBACKINIT);
3240 mptcp_subflow_early_fallback(msk, subflow);
3242 if (likely(!__mptcp_check_fallback(msk)))
3243 MPTCP_INC_STATS(sock_net(sock->sk), MPTCP_MIB_MPCAPABLEACTIVE);
3246 err = ssock->ops->connect(ssock, uaddr, addr_len, flags);
3247 sock->state = ssock->state;
3249 /* on successful connect, the msk state will be moved to established by
3250 * subflow_finish_connect()
3252 if (!err || err == -EINPROGRESS)
3253 mptcp_copy_inaddrs(sock->sk, ssock->sk);
3255 inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
3258 release_sock(sock->sk);
3262 static int mptcp_listen(struct socket *sock, int backlog)
3264 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3265 struct socket *ssock;
3268 pr_debug("msk=%p", msk);
3270 lock_sock(sock->sk);
3271 ssock = __mptcp_nmpc_socket(msk);
3277 mptcp_token_destroy(msk);
3278 inet_sk_state_store(sock->sk, TCP_LISTEN);
3279 sock_set_flag(sock->sk, SOCK_RCU_FREE);
3281 err = ssock->ops->listen(ssock, backlog);
3282 inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
3284 mptcp_copy_inaddrs(sock->sk, ssock->sk);
3287 release_sock(sock->sk);
3291 static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
3292 int flags, bool kern)
3294 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3295 struct socket *ssock;
3298 pr_debug("msk=%p", msk);
3300 lock_sock(sock->sk);
3301 if (sock->sk->sk_state != TCP_LISTEN)
3304 ssock = __mptcp_nmpc_socket(msk);
3308 clear_bit(MPTCP_DATA_READY, &msk->flags);
3309 sock_hold(ssock->sk);
3310 release_sock(sock->sk);
3312 err = ssock->ops->accept(sock, newsock, flags, kern);
3313 if (err == 0 && !mptcp_is_tcpsk(newsock->sk)) {
3314 struct mptcp_sock *msk = mptcp_sk(newsock->sk);
3315 struct mptcp_subflow_context *subflow;
3316 struct sock *newsk = newsock->sk;
3320 /* PM/worker can now acquire the first subflow socket
3321 * lock without racing with listener queue cleanup,
3322 * we can notify it, if needed.
3324 * Even if remote has reset the initial subflow by now
3325 * the refcnt is still at least one.
3327 subflow = mptcp_subflow_ctx(msk->first);
3328 list_add(&subflow->node, &msk->conn_list);
3329 sock_hold(msk->first);
3330 if (mptcp_is_fully_established(newsk))
3331 mptcp_pm_fully_established(msk, msk->first, GFP_KERNEL);
3333 mptcp_copy_inaddrs(newsk, msk->first);
3334 mptcp_rcv_space_init(msk, msk->first);
3335 mptcp_propagate_sndbuf(newsk, msk->first);
3337 /* set ssk->sk_socket of accept()ed flows to mptcp socket.
3338 * This is needed so NOSPACE flag can be set from tcp stack.
3340 mptcp_flush_join_list(msk);
3341 mptcp_for_each_subflow(msk, subflow) {
3342 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3344 if (!ssk->sk_socket)
3345 mptcp_sock_graft(ssk, newsock);
3347 release_sock(newsk);
3350 if (inet_csk_listen_poll(ssock->sk))
3351 set_bit(MPTCP_DATA_READY, &msk->flags);
3352 sock_put(ssock->sk);
3356 release_sock(sock->sk);
3360 static __poll_t mptcp_check_readable(struct mptcp_sock *msk)
3362 /* Concurrent splices from sk_receive_queue into receive_queue will
3363 * always show at least one non-empty queue when checked in this order.
3365 if (skb_queue_empty_lockless(&((struct sock *)msk)->sk_receive_queue) &&
3366 skb_queue_empty_lockless(&msk->receive_queue))
3369 return EPOLLIN | EPOLLRDNORM;
3372 static __poll_t mptcp_check_writeable(struct mptcp_sock *msk)
3374 struct sock *sk = (struct sock *)msk;
3376 if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
3377 return EPOLLOUT | EPOLLWRNORM;
3379 if (sk_stream_is_writeable(sk))
3380 return EPOLLOUT | EPOLLWRNORM;
3382 mptcp_set_nospace(sk);
3383 smp_mb__after_atomic(); /* msk->flags is changed by write_space cb */
3384 if (sk_stream_is_writeable(sk))
3385 return EPOLLOUT | EPOLLWRNORM;
3390 static __poll_t mptcp_poll(struct file *file, struct socket *sock,
3391 struct poll_table_struct *wait)
3393 struct sock *sk = sock->sk;
3394 struct mptcp_sock *msk;
3399 sock_poll_wait(file, sock, wait);
3401 state = inet_sk_state_load(sk);
3402 pr_debug("msk=%p state=%d flags=%lx", msk, state, msk->flags);
3403 if (state == TCP_LISTEN)
3404 return test_bit(MPTCP_DATA_READY, &msk->flags) ? EPOLLIN | EPOLLRDNORM : 0;
3406 if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) {
3407 mask |= mptcp_check_readable(msk);
3408 mask |= mptcp_check_writeable(msk);
3410 if (sk->sk_shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
3412 if (sk->sk_shutdown & RCV_SHUTDOWN)
3413 mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
3415 /* This barrier is coupled with smp_wmb() in tcp_reset() */
3423 static const struct proto_ops mptcp_stream_ops = {
3425 .owner = THIS_MODULE,
3426 .release = inet_release,
3428 .connect = mptcp_stream_connect,
3429 .socketpair = sock_no_socketpair,
3430 .accept = mptcp_stream_accept,
3431 .getname = inet_getname,
3433 .ioctl = inet_ioctl,
3434 .gettstamp = sock_gettstamp,
3435 .listen = mptcp_listen,
3436 .shutdown = inet_shutdown,
3437 .setsockopt = sock_common_setsockopt,
3438 .getsockopt = sock_common_getsockopt,
3439 .sendmsg = inet_sendmsg,
3440 .recvmsg = inet_recvmsg,
3441 .mmap = sock_no_mmap,
3442 .sendpage = inet_sendpage,
3445 static struct inet_protosw mptcp_protosw = {
3446 .type = SOCK_STREAM,
3447 .protocol = IPPROTO_MPTCP,
3448 .prot = &mptcp_prot,
3449 .ops = &mptcp_stream_ops,
3450 .flags = INET_PROTOSW_ICSK,
3453 static int mptcp_napi_poll(struct napi_struct *napi, int budget)
3455 struct mptcp_delegated_action *delegated;
3456 struct mptcp_subflow_context *subflow;
3459 delegated = container_of(napi, struct mptcp_delegated_action, napi);
3460 while ((subflow = mptcp_subflow_delegated_next(delegated)) != NULL) {
3461 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3463 bh_lock_sock_nested(ssk);
3464 if (!sock_owned_by_user(ssk) &&
3465 mptcp_subflow_has_delegated_action(subflow))
3466 mptcp_subflow_process_delegated(ssk);
3467 /* ... elsewhere tcp_release_cb_override already processed
3468 * the action or will do at next release_sock().
3469 * In both case must dequeue the subflow here - on the same
3470 * CPU that scheduled it.
3472 bh_unlock_sock(ssk);
3475 if (++work_done == budget)
3479 /* always provide a 0 'work_done' argument, so that napi_complete_done
3480 * will not try accessing the NULL napi->dev ptr
3482 napi_complete_done(napi, 0);
3486 void __init mptcp_proto_init(void)
3488 struct mptcp_delegated_action *delegated;
3491 mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo;
3493 if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL))
3494 panic("Failed to allocate MPTCP pcpu counter\n");
3496 init_dummy_netdev(&mptcp_napi_dev);
3497 for_each_possible_cpu(cpu) {
3498 delegated = per_cpu_ptr(&mptcp_delegated_actions, cpu);
3499 INIT_LIST_HEAD(&delegated->head);
3500 netif_tx_napi_add(&mptcp_napi_dev, &delegated->napi, mptcp_napi_poll,
3502 napi_enable(&delegated->napi);
3505 mptcp_subflow_init();
3509 if (proto_register(&mptcp_prot, 1) != 0)
3510 panic("Failed to register MPTCP proto.\n");
3512 inet_register_protosw(&mptcp_protosw);
3514 BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb));
3517 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
3518 static const struct proto_ops mptcp_v6_stream_ops = {
3520 .owner = THIS_MODULE,
3521 .release = inet6_release,
3523 .connect = mptcp_stream_connect,
3524 .socketpair = sock_no_socketpair,
3525 .accept = mptcp_stream_accept,
3526 .getname = inet6_getname,
3528 .ioctl = inet6_ioctl,
3529 .gettstamp = sock_gettstamp,
3530 .listen = mptcp_listen,
3531 .shutdown = inet_shutdown,
3532 .setsockopt = sock_common_setsockopt,
3533 .getsockopt = sock_common_getsockopt,
3534 .sendmsg = inet6_sendmsg,
3535 .recvmsg = inet6_recvmsg,
3536 .mmap = sock_no_mmap,
3537 .sendpage = inet_sendpage,
3538 #ifdef CONFIG_COMPAT
3539 .compat_ioctl = inet6_compat_ioctl,
3543 static struct proto mptcp_v6_prot;
3545 static void mptcp_v6_destroy(struct sock *sk)
3548 inet6_destroy_sock(sk);
3551 static struct inet_protosw mptcp_v6_protosw = {
3552 .type = SOCK_STREAM,
3553 .protocol = IPPROTO_MPTCP,
3554 .prot = &mptcp_v6_prot,
3555 .ops = &mptcp_v6_stream_ops,
3556 .flags = INET_PROTOSW_ICSK,
3559 int __init mptcp_proto_v6_init(void)
3563 mptcp_v6_prot = mptcp_prot;
3564 strcpy(mptcp_v6_prot.name, "MPTCPv6");
3565 mptcp_v6_prot.slab = NULL;
3566 mptcp_v6_prot.destroy = mptcp_v6_destroy;
3567 mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock);
3569 err = proto_register(&mptcp_v6_prot, 1);
3573 err = inet6_register_protosw(&mptcp_v6_protosw);
3575 proto_unregister(&mptcp_v6_prot);