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>
25 #include <asm/ioctls.h>
29 #define CREATE_TRACE_POINTS
30 #include <trace/events/mptcp.h>
32 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
34 struct mptcp_sock msk;
46 #define MPTCP_SKB_CB(__skb) ((struct mptcp_skb_cb *)&((__skb)->cb[0]))
49 MPTCP_CMSG_TS = BIT(0),
50 MPTCP_CMSG_INQ = BIT(1),
53 static struct percpu_counter mptcp_sockets_allocated ____cacheline_aligned_in_smp;
55 static void __mptcp_destroy_sock(struct sock *sk);
56 static void __mptcp_check_send_data_fin(struct sock *sk);
58 DEFINE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
59 static struct net_device mptcp_napi_dev;
61 /* If msk has an initial subflow socket, and the MP_CAPABLE handshake has not
62 * completed yet or has failed, return the subflow socket.
63 * Otherwise return NULL.
65 struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk)
67 if (!msk->subflow || READ_ONCE(msk->can_ack))
73 /* Returns end sequence number of the receiver's advertised window */
74 static u64 mptcp_wnd_end(const struct mptcp_sock *msk)
76 return READ_ONCE(msk->wnd_end);
79 static bool mptcp_is_tcpsk(struct sock *sk)
81 struct socket *sock = sk->sk_socket;
83 if (unlikely(sk->sk_prot == &tcp_prot)) {
84 /* we are being invoked after mptcp_accept() has
85 * accepted a non-mp-capable flow: sk is a tcp_sk,
88 * Hand the socket over to tcp so all further socket ops
91 sock->ops = &inet_stream_ops;
93 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
94 } else if (unlikely(sk->sk_prot == &tcpv6_prot)) {
95 sock->ops = &inet6_stream_ops;
103 static int __mptcp_socket_create(struct mptcp_sock *msk)
105 struct mptcp_subflow_context *subflow;
106 struct sock *sk = (struct sock *)msk;
107 struct socket *ssock;
110 err = mptcp_subflow_create_socket(sk, sk->sk_family, &ssock);
114 WRITE_ONCE(msk->first, ssock->sk);
115 WRITE_ONCE(msk->subflow, ssock);
116 subflow = mptcp_subflow_ctx(ssock->sk);
117 list_add(&subflow->node, &msk->conn_list);
118 sock_hold(ssock->sk);
119 subflow->request_mptcp = 1;
121 /* This is the first subflow, always with id 0 */
122 subflow->local_id_valid = 1;
123 mptcp_sock_graft(msk->first, sk->sk_socket);
128 static void mptcp_drop(struct sock *sk, struct sk_buff *skb)
130 sk_drops_add(sk, skb);
134 static void mptcp_rmem_charge(struct sock *sk, int size)
136 mptcp_sk(sk)->rmem_fwd_alloc -= size;
139 static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to,
140 struct sk_buff *from)
145 if (MPTCP_SKB_CB(from)->offset ||
146 !skb_try_coalesce(to, from, &fragstolen, &delta))
149 pr_debug("colesced seq %llx into %llx new len %d new end seq %llx",
150 MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq,
151 to->len, MPTCP_SKB_CB(from)->end_seq);
152 MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq;
154 /* note the fwd memory can reach a negative value after accounting
155 * for the delta, but the later skb free will restore a non
158 atomic_add(delta, &sk->sk_rmem_alloc);
159 mptcp_rmem_charge(sk, delta);
160 kfree_skb_partial(from, fragstolen);
165 static bool mptcp_ooo_try_coalesce(struct mptcp_sock *msk, struct sk_buff *to,
166 struct sk_buff *from)
168 if (MPTCP_SKB_CB(from)->map_seq != MPTCP_SKB_CB(to)->end_seq)
171 return mptcp_try_coalesce((struct sock *)msk, to, from);
174 static void __mptcp_rmem_reclaim(struct sock *sk, int amount)
176 amount >>= PAGE_SHIFT;
177 mptcp_sk(sk)->rmem_fwd_alloc -= amount << PAGE_SHIFT;
178 __sk_mem_reduce_allocated(sk, amount);
181 static void mptcp_rmem_uncharge(struct sock *sk, int size)
183 struct mptcp_sock *msk = mptcp_sk(sk);
186 msk->rmem_fwd_alloc += size;
187 reclaimable = msk->rmem_fwd_alloc - sk_unused_reserved_mem(sk);
189 /* see sk_mem_uncharge() for the rationale behind the following schema */
190 if (unlikely(reclaimable >= PAGE_SIZE))
191 __mptcp_rmem_reclaim(sk, reclaimable);
194 static void mptcp_rfree(struct sk_buff *skb)
196 unsigned int len = skb->truesize;
197 struct sock *sk = skb->sk;
199 atomic_sub(len, &sk->sk_rmem_alloc);
200 mptcp_rmem_uncharge(sk, len);
203 static void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk)
207 skb->destructor = mptcp_rfree;
208 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
209 mptcp_rmem_charge(sk, skb->truesize);
212 /* "inspired" by tcp_data_queue_ofo(), main differences:
214 * - don't cope with sacks
216 static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb)
218 struct sock *sk = (struct sock *)msk;
219 struct rb_node **p, *parent;
220 u64 seq, end_seq, max_seq;
221 struct sk_buff *skb1;
223 seq = MPTCP_SKB_CB(skb)->map_seq;
224 end_seq = MPTCP_SKB_CB(skb)->end_seq;
225 max_seq = atomic64_read(&msk->rcv_wnd_sent);
227 pr_debug("msk=%p seq=%llx limit=%llx empty=%d", msk, seq, max_seq,
228 RB_EMPTY_ROOT(&msk->out_of_order_queue));
229 if (after64(end_seq, max_seq)) {
232 pr_debug("oow by %lld, rcv_wnd_sent %llu\n",
233 (unsigned long long)end_seq - (unsigned long)max_seq,
234 (unsigned long long)atomic64_read(&msk->rcv_wnd_sent));
235 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_NODSSWINDOW);
239 p = &msk->out_of_order_queue.rb_node;
240 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUE);
241 if (RB_EMPTY_ROOT(&msk->out_of_order_queue)) {
242 rb_link_node(&skb->rbnode, NULL, p);
243 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
244 msk->ooo_last_skb = skb;
248 /* with 2 subflows, adding at end of ooo queue is quite likely
249 * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup.
251 if (mptcp_ooo_try_coalesce(msk, msk->ooo_last_skb, skb)) {
252 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
253 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
257 /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */
258 if (!before64(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) {
259 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
260 parent = &msk->ooo_last_skb->rbnode;
261 p = &parent->rb_right;
265 /* Find place to insert this segment. Handle overlaps on the way. */
269 skb1 = rb_to_skb(parent);
270 if (before64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
271 p = &parent->rb_left;
274 if (before64(seq, MPTCP_SKB_CB(skb1)->end_seq)) {
275 if (!after64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) {
276 /* All the bits are present. Drop. */
278 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
281 if (after64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
285 * continue traversing
288 /* skb's seq == skb1's seq and skb covers skb1.
289 * Replace skb1 with skb.
291 rb_replace_node(&skb1->rbnode, &skb->rbnode,
292 &msk->out_of_order_queue);
293 mptcp_drop(sk, skb1);
294 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
297 } else if (mptcp_ooo_try_coalesce(msk, skb1, skb)) {
298 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
301 p = &parent->rb_right;
305 /* Insert segment into RB tree. */
306 rb_link_node(&skb->rbnode, parent, p);
307 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
310 /* Remove other segments covered by skb. */
311 while ((skb1 = skb_rb_next(skb)) != NULL) {
312 if (before64(end_seq, MPTCP_SKB_CB(skb1)->end_seq))
314 rb_erase(&skb1->rbnode, &msk->out_of_order_queue);
315 mptcp_drop(sk, skb1);
316 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
318 /* If there is no skb after us, we are the last_skb ! */
320 msk->ooo_last_skb = skb;
324 mptcp_set_owner_r(skb, sk);
327 static bool mptcp_rmem_schedule(struct sock *sk, struct sock *ssk, int size)
329 struct mptcp_sock *msk = mptcp_sk(sk);
332 if (size <= msk->rmem_fwd_alloc)
335 size -= msk->rmem_fwd_alloc;
336 amt = sk_mem_pages(size);
337 amount = amt << PAGE_SHIFT;
338 if (!__sk_mem_raise_allocated(sk, size, amt, SK_MEM_RECV))
341 msk->rmem_fwd_alloc += amount;
345 static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk,
346 struct sk_buff *skb, unsigned int offset,
349 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
350 struct sock *sk = (struct sock *)msk;
351 struct sk_buff *tail;
354 __skb_unlink(skb, &ssk->sk_receive_queue);
359 /* try to fetch required memory from subflow */
360 if (!mptcp_rmem_schedule(sk, ssk, skb->truesize))
363 has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp;
365 /* the skb map_seq accounts for the skb offset:
366 * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq
369 MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow);
370 MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len;
371 MPTCP_SKB_CB(skb)->offset = offset;
372 MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp;
374 if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) {
376 WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len);
377 tail = skb_peek_tail(&sk->sk_receive_queue);
378 if (tail && mptcp_try_coalesce(sk, tail, skb))
381 mptcp_set_owner_r(skb, sk);
382 __skb_queue_tail(&sk->sk_receive_queue, skb);
384 } else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) {
385 mptcp_data_queue_ofo(msk, skb);
389 /* old data, keep it simple and drop the whole pkt, sender
390 * will retransmit as needed, if needed.
392 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
398 static void mptcp_stop_timer(struct sock *sk)
400 struct inet_connection_sock *icsk = inet_csk(sk);
402 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
403 mptcp_sk(sk)->timer_ival = 0;
406 static void mptcp_close_wake_up(struct sock *sk)
408 if (sock_flag(sk, SOCK_DEAD))
411 sk->sk_state_change(sk);
412 if (sk->sk_shutdown == SHUTDOWN_MASK ||
413 sk->sk_state == TCP_CLOSE)
414 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
416 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
419 static bool mptcp_pending_data_fin_ack(struct sock *sk)
421 struct mptcp_sock *msk = mptcp_sk(sk);
423 return !__mptcp_check_fallback(msk) &&
424 ((1 << sk->sk_state) &
425 (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) &&
426 msk->write_seq == READ_ONCE(msk->snd_una);
429 static void mptcp_check_data_fin_ack(struct sock *sk)
431 struct mptcp_sock *msk = mptcp_sk(sk);
433 /* Look for an acknowledged DATA_FIN */
434 if (mptcp_pending_data_fin_ack(sk)) {
435 WRITE_ONCE(msk->snd_data_fin_enable, 0);
437 switch (sk->sk_state) {
439 inet_sk_state_store(sk, TCP_FIN_WAIT2);
443 inet_sk_state_store(sk, TCP_CLOSE);
447 mptcp_close_wake_up(sk);
451 static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq)
453 struct mptcp_sock *msk = mptcp_sk(sk);
455 if (READ_ONCE(msk->rcv_data_fin) &&
456 ((1 << sk->sk_state) &
457 (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) {
458 u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq);
460 if (msk->ack_seq == rcv_data_fin_seq) {
462 *seq = rcv_data_fin_seq;
471 static void mptcp_set_datafin_timeout(const struct sock *sk)
473 struct inet_connection_sock *icsk = inet_csk(sk);
476 retransmits = min_t(u32, icsk->icsk_retransmits,
477 ilog2(TCP_RTO_MAX / TCP_RTO_MIN));
479 mptcp_sk(sk)->timer_ival = TCP_RTO_MIN << retransmits;
482 static void __mptcp_set_timeout(struct sock *sk, long tout)
484 mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
487 static long mptcp_timeout_from_subflow(const struct mptcp_subflow_context *subflow)
489 const struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
491 return inet_csk(ssk)->icsk_pending && !subflow->stale_count ?
492 inet_csk(ssk)->icsk_timeout - jiffies : 0;
495 static void mptcp_set_timeout(struct sock *sk)
497 struct mptcp_subflow_context *subflow;
500 mptcp_for_each_subflow(mptcp_sk(sk), subflow)
501 tout = max(tout, mptcp_timeout_from_subflow(subflow));
502 __mptcp_set_timeout(sk, tout);
505 static inline bool tcp_can_send_ack(const struct sock *ssk)
507 return !((1 << inet_sk_state_load(ssk)) &
508 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE | TCPF_LISTEN));
511 void __mptcp_subflow_send_ack(struct sock *ssk)
513 if (tcp_can_send_ack(ssk))
517 static void mptcp_subflow_send_ack(struct sock *ssk)
521 slow = lock_sock_fast(ssk);
522 __mptcp_subflow_send_ack(ssk);
523 unlock_sock_fast(ssk, slow);
526 static void mptcp_send_ack(struct mptcp_sock *msk)
528 struct mptcp_subflow_context *subflow;
530 mptcp_for_each_subflow(msk, subflow)
531 mptcp_subflow_send_ack(mptcp_subflow_tcp_sock(subflow));
534 static void mptcp_subflow_cleanup_rbuf(struct sock *ssk)
538 slow = lock_sock_fast(ssk);
539 if (tcp_can_send_ack(ssk))
540 tcp_cleanup_rbuf(ssk, 1);
541 unlock_sock_fast(ssk, slow);
544 static bool mptcp_subflow_could_cleanup(const struct sock *ssk, bool rx_empty)
546 const struct inet_connection_sock *icsk = inet_csk(ssk);
547 u8 ack_pending = READ_ONCE(icsk->icsk_ack.pending);
548 const struct tcp_sock *tp = tcp_sk(ssk);
550 return (ack_pending & ICSK_ACK_SCHED) &&
551 ((READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->rcv_wup) >
552 READ_ONCE(icsk->icsk_ack.rcv_mss)) ||
553 (rx_empty && ack_pending &
554 (ICSK_ACK_PUSHED2 | ICSK_ACK_PUSHED)));
557 static void mptcp_cleanup_rbuf(struct mptcp_sock *msk)
559 int old_space = READ_ONCE(msk->old_wspace);
560 struct mptcp_subflow_context *subflow;
561 struct sock *sk = (struct sock *)msk;
562 int space = __mptcp_space(sk);
563 bool cleanup, rx_empty;
565 cleanup = (space > 0) && (space >= (old_space << 1));
566 rx_empty = !__mptcp_rmem(sk);
568 mptcp_for_each_subflow(msk, subflow) {
569 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
571 if (cleanup || mptcp_subflow_could_cleanup(ssk, rx_empty))
572 mptcp_subflow_cleanup_rbuf(ssk);
576 static bool mptcp_check_data_fin(struct sock *sk)
578 struct mptcp_sock *msk = mptcp_sk(sk);
579 u64 rcv_data_fin_seq;
582 if (__mptcp_check_fallback(msk))
585 /* Need to ack a DATA_FIN received from a peer while this side
586 * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2.
587 * msk->rcv_data_fin was set when parsing the incoming options
588 * at the subflow level and the msk lock was not held, so this
589 * is the first opportunity to act on the DATA_FIN and change
592 * If we are caught up to the sequence number of the incoming
593 * DATA_FIN, send the DATA_ACK now and do state transition. If
594 * not caught up, do nothing and let the recv code send DATA_ACK
598 if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) {
599 WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1);
600 WRITE_ONCE(msk->rcv_data_fin, 0);
602 WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | RCV_SHUTDOWN);
603 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
605 switch (sk->sk_state) {
606 case TCP_ESTABLISHED:
607 inet_sk_state_store(sk, TCP_CLOSE_WAIT);
610 inet_sk_state_store(sk, TCP_CLOSING);
613 inet_sk_state_store(sk, TCP_CLOSE);
616 /* Other states not expected */
623 mptcp_close_wake_up(sk);
628 static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
632 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
633 struct sock *sk = (struct sock *)msk;
634 unsigned int moved = 0;
635 bool more_data_avail;
640 sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
642 if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
643 int ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
645 if (unlikely(ssk_rbuf > sk_rbuf)) {
646 WRITE_ONCE(sk->sk_rcvbuf, ssk_rbuf);
651 pr_debug("msk=%p ssk=%p", msk, ssk);
654 u32 map_remaining, offset;
655 u32 seq = tp->copied_seq;
659 /* try to move as much data as available */
660 map_remaining = subflow->map_data_len -
661 mptcp_subflow_get_map_offset(subflow);
663 skb = skb_peek(&ssk->sk_receive_queue);
665 /* With racing move_skbs_to_msk() and __mptcp_move_skbs(),
666 * a different CPU can have already processed the pending
667 * data, stop here or we can enter an infinite loop
674 if (__mptcp_check_fallback(msk)) {
675 /* Under fallback skbs have no MPTCP extension and TCP could
676 * collapse them between the dummy map creation and the
677 * current dequeue. Be sure to adjust the map size.
679 map_remaining = skb->len;
680 subflow->map_data_len = skb->len;
683 offset = seq - TCP_SKB_CB(skb)->seq;
684 fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
690 if (offset < skb->len) {
691 size_t len = skb->len - offset;
696 if (__mptcp_move_skb(msk, ssk, skb, offset, len))
700 if (WARN_ON_ONCE(map_remaining < len))
704 sk_eat_skb(ssk, skb);
708 WRITE_ONCE(tp->copied_seq, seq);
709 more_data_avail = mptcp_subflow_data_available(ssk);
711 if (atomic_read(&sk->sk_rmem_alloc) > sk_rbuf) {
715 } while (more_data_avail);
721 static bool __mptcp_ofo_queue(struct mptcp_sock *msk)
723 struct sock *sk = (struct sock *)msk;
724 struct sk_buff *skb, *tail;
729 p = rb_first(&msk->out_of_order_queue);
730 pr_debug("msk=%p empty=%d", msk, RB_EMPTY_ROOT(&msk->out_of_order_queue));
733 if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq))
737 rb_erase(&skb->rbnode, &msk->out_of_order_queue);
739 if (unlikely(!after64(MPTCP_SKB_CB(skb)->end_seq,
742 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
746 end_seq = MPTCP_SKB_CB(skb)->end_seq;
747 tail = skb_peek_tail(&sk->sk_receive_queue);
748 if (!tail || !mptcp_ooo_try_coalesce(msk, tail, skb)) {
749 int delta = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq;
751 /* skip overlapping data, if any */
752 pr_debug("uncoalesced seq=%llx ack seq=%llx delta=%d",
753 MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq,
755 MPTCP_SKB_CB(skb)->offset += delta;
756 MPTCP_SKB_CB(skb)->map_seq += delta;
757 __skb_queue_tail(&sk->sk_receive_queue, skb);
759 msk->ack_seq = end_seq;
765 /* In most cases we will be able to lock the mptcp socket. If its already
766 * owned, we need to defer to the work queue to avoid ABBA deadlock.
768 static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk)
770 struct sock *sk = (struct sock *)msk;
771 unsigned int moved = 0;
773 __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
774 __mptcp_ofo_queue(msk);
775 if (unlikely(ssk->sk_err)) {
776 if (!sock_owned_by_user(sk))
777 __mptcp_error_report(sk);
779 __set_bit(MPTCP_ERROR_REPORT, &msk->cb_flags);
782 /* If the moves have caught up with the DATA_FIN sequence number
783 * it's time to ack the DATA_FIN and change socket state, but
784 * this is not a good place to change state. Let the workqueue
787 if (mptcp_pending_data_fin(sk, NULL))
788 mptcp_schedule_work(sk);
792 void mptcp_data_ready(struct sock *sk, struct sock *ssk)
794 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
795 struct mptcp_sock *msk = mptcp_sk(sk);
796 int sk_rbuf, ssk_rbuf;
798 /* The peer can send data while we are shutting down this
799 * subflow at msk destruction time, but we must avoid enqueuing
800 * more data to the msk receive queue
802 if (unlikely(subflow->disposable))
805 ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
806 sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
807 if (unlikely(ssk_rbuf > sk_rbuf))
810 /* over limit? can't append more skbs to msk, Also, no need to wake-up*/
811 if (__mptcp_rmem(sk) > sk_rbuf) {
812 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED);
816 /* Wake-up the reader only for in-sequence data */
818 if (move_skbs_to_msk(msk, ssk))
819 sk->sk_data_ready(sk);
821 mptcp_data_unlock(sk);
824 static void mptcp_subflow_joined(struct mptcp_sock *msk, struct sock *ssk)
826 mptcp_subflow_ctx(ssk)->map_seq = READ_ONCE(msk->ack_seq);
827 WRITE_ONCE(msk->allow_infinite_fallback, false);
828 mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC);
831 static bool __mptcp_finish_join(struct mptcp_sock *msk, struct sock *ssk)
833 struct sock *sk = (struct sock *)msk;
835 if (sk->sk_state != TCP_ESTABLISHED)
838 /* attach to msk socket only after we are sure we will deal with it
841 if (sk->sk_socket && !ssk->sk_socket)
842 mptcp_sock_graft(ssk, sk->sk_socket);
844 mptcp_sockopt_sync_locked(msk, ssk);
845 mptcp_subflow_joined(msk, ssk);
849 static void __mptcp_flush_join_list(struct sock *sk)
851 struct mptcp_subflow_context *tmp, *subflow;
852 struct mptcp_sock *msk = mptcp_sk(sk);
854 list_for_each_entry_safe(subflow, tmp, &msk->join_list, node) {
855 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
856 bool slow = lock_sock_fast(ssk);
858 list_move_tail(&subflow->node, &msk->conn_list);
859 if (!__mptcp_finish_join(msk, ssk))
860 mptcp_subflow_reset(ssk);
861 unlock_sock_fast(ssk, slow);
865 static bool mptcp_timer_pending(struct sock *sk)
867 return timer_pending(&inet_csk(sk)->icsk_retransmit_timer);
870 static void mptcp_reset_timer(struct sock *sk)
872 struct inet_connection_sock *icsk = inet_csk(sk);
875 /* prevent rescheduling on close */
876 if (unlikely(inet_sk_state_load(sk) == TCP_CLOSE))
879 tout = mptcp_sk(sk)->timer_ival;
880 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout);
883 bool mptcp_schedule_work(struct sock *sk)
885 if (inet_sk_state_load(sk) != TCP_CLOSE &&
886 schedule_work(&mptcp_sk(sk)->work)) {
887 /* each subflow already holds a reference to the sk, and the
888 * workqueue is invoked by a subflow, so sk can't go away here.
896 void mptcp_subflow_eof(struct sock *sk)
898 if (!test_and_set_bit(MPTCP_WORK_EOF, &mptcp_sk(sk)->flags))
899 mptcp_schedule_work(sk);
902 static void mptcp_check_for_eof(struct mptcp_sock *msk)
904 struct mptcp_subflow_context *subflow;
905 struct sock *sk = (struct sock *)msk;
908 mptcp_for_each_subflow(msk, subflow)
909 receivers += !subflow->rx_eof;
913 if (!(sk->sk_shutdown & RCV_SHUTDOWN)) {
914 /* hopefully temporary hack: propagate shutdown status
915 * to msk, when all subflows agree on it
917 WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | RCV_SHUTDOWN);
919 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
920 sk->sk_data_ready(sk);
923 switch (sk->sk_state) {
924 case TCP_ESTABLISHED:
925 inet_sk_state_store(sk, TCP_CLOSE_WAIT);
928 inet_sk_state_store(sk, TCP_CLOSING);
931 inet_sk_state_store(sk, TCP_CLOSE);
936 mptcp_close_wake_up(sk);
939 static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk)
941 struct mptcp_subflow_context *subflow;
942 struct sock *sk = (struct sock *)msk;
944 sock_owned_by_me(sk);
946 mptcp_for_each_subflow(msk, subflow) {
947 if (READ_ONCE(subflow->data_avail))
948 return mptcp_subflow_tcp_sock(subflow);
954 static bool mptcp_skb_can_collapse_to(u64 write_seq,
955 const struct sk_buff *skb,
956 const struct mptcp_ext *mpext)
958 if (!tcp_skb_can_collapse_to(skb))
961 /* can collapse only if MPTCP level sequence is in order and this
962 * mapping has not been xmitted yet
964 return mpext && mpext->data_seq + mpext->data_len == write_seq &&
968 /* we can append data to the given data frag if:
969 * - there is space available in the backing page_frag
970 * - the data frag tail matches the current page_frag free offset
971 * - the data frag end sequence number matches the current write seq
973 static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk,
974 const struct page_frag *pfrag,
975 const struct mptcp_data_frag *df)
977 return df && pfrag->page == df->page &&
978 pfrag->size - pfrag->offset > 0 &&
979 pfrag->offset == (df->offset + df->data_len) &&
980 df->data_seq + df->data_len == msk->write_seq;
983 static void dfrag_uncharge(struct sock *sk, int len)
985 sk_mem_uncharge(sk, len);
986 sk_wmem_queued_add(sk, -len);
989 static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag)
991 int len = dfrag->data_len + dfrag->overhead;
993 list_del(&dfrag->list);
994 dfrag_uncharge(sk, len);
995 put_page(dfrag->page);
998 static void __mptcp_clean_una(struct sock *sk)
1000 struct mptcp_sock *msk = mptcp_sk(sk);
1001 struct mptcp_data_frag *dtmp, *dfrag;
1004 /* on fallback we just need to ignore snd_una, as this is really
1007 if (__mptcp_check_fallback(msk))
1008 msk->snd_una = READ_ONCE(msk->snd_nxt);
1010 snd_una = msk->snd_una;
1011 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) {
1012 if (after64(dfrag->data_seq + dfrag->data_len, snd_una))
1015 if (unlikely(dfrag == msk->first_pending)) {
1016 /* in recovery mode can see ack after the current snd head */
1017 if (WARN_ON_ONCE(!msk->recovery))
1020 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1023 dfrag_clear(sk, dfrag);
1026 dfrag = mptcp_rtx_head(sk);
1027 if (dfrag && after64(snd_una, dfrag->data_seq)) {
1028 u64 delta = snd_una - dfrag->data_seq;
1030 /* prevent wrap around in recovery mode */
1031 if (unlikely(delta > dfrag->already_sent)) {
1032 if (WARN_ON_ONCE(!msk->recovery))
1034 if (WARN_ON_ONCE(delta > dfrag->data_len))
1036 dfrag->already_sent += 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);
1047 /* all retransmitted data acked, recovery completed */
1048 if (unlikely(msk->recovery) && after64(msk->snd_una, msk->recovery_snd_nxt))
1049 msk->recovery = false;
1052 if (snd_una == READ_ONCE(msk->snd_nxt) &&
1053 snd_una == READ_ONCE(msk->write_seq)) {
1054 if (mptcp_timer_pending(sk) && !mptcp_data_fin_enabled(msk))
1055 mptcp_stop_timer(sk);
1057 mptcp_reset_timer(sk);
1061 static void __mptcp_clean_una_wakeup(struct sock *sk)
1063 lockdep_assert_held_once(&sk->sk_lock.slock);
1065 __mptcp_clean_una(sk);
1066 mptcp_write_space(sk);
1069 static void mptcp_clean_una_wakeup(struct sock *sk)
1071 mptcp_data_lock(sk);
1072 __mptcp_clean_una_wakeup(sk);
1073 mptcp_data_unlock(sk);
1076 static void mptcp_enter_memory_pressure(struct sock *sk)
1078 struct mptcp_subflow_context *subflow;
1079 struct mptcp_sock *msk = mptcp_sk(sk);
1082 sk_stream_moderate_sndbuf(sk);
1083 mptcp_for_each_subflow(msk, subflow) {
1084 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
1087 tcp_enter_memory_pressure(ssk);
1088 sk_stream_moderate_sndbuf(ssk);
1093 /* ensure we get enough memory for the frag hdr, beyond some minimal amount of
1096 static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag)
1098 if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag),
1099 pfrag, sk->sk_allocation)))
1102 mptcp_enter_memory_pressure(sk);
1106 static struct mptcp_data_frag *
1107 mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag,
1110 int offset = ALIGN(orig_offset, sizeof(long));
1111 struct mptcp_data_frag *dfrag;
1113 dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset);
1114 dfrag->data_len = 0;
1115 dfrag->data_seq = msk->write_seq;
1116 dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag);
1117 dfrag->offset = offset + sizeof(struct mptcp_data_frag);
1118 dfrag->already_sent = 0;
1119 dfrag->page = pfrag->page;
1124 struct mptcp_sendmsg_info {
1130 bool data_lock_held;
1133 static int mptcp_check_allowed_size(const struct mptcp_sock *msk, struct sock *ssk,
1134 u64 data_seq, int avail_size)
1136 u64 window_end = mptcp_wnd_end(msk);
1139 if (__mptcp_check_fallback(msk))
1142 mptcp_snd_wnd = window_end - data_seq;
1143 avail_size = min_t(unsigned int, mptcp_snd_wnd, avail_size);
1145 if (unlikely(tcp_sk(ssk)->snd_wnd < mptcp_snd_wnd)) {
1146 tcp_sk(ssk)->snd_wnd = min_t(u64, U32_MAX, mptcp_snd_wnd);
1147 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_SNDWNDSHARED);
1153 static bool __mptcp_add_ext(struct sk_buff *skb, gfp_t gfp)
1155 struct skb_ext *mpext = __skb_ext_alloc(gfp);
1159 __skb_ext_set(skb, SKB_EXT_MPTCP, mpext);
1163 static struct sk_buff *__mptcp_do_alloc_tx_skb(struct sock *sk, gfp_t gfp)
1165 struct sk_buff *skb;
1167 skb = alloc_skb_fclone(MAX_TCP_HEADER, gfp);
1169 if (likely(__mptcp_add_ext(skb, gfp))) {
1170 skb_reserve(skb, MAX_TCP_HEADER);
1171 skb->ip_summed = CHECKSUM_PARTIAL;
1172 INIT_LIST_HEAD(&skb->tcp_tsorted_anchor);
1177 mptcp_enter_memory_pressure(sk);
1182 static struct sk_buff *__mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, gfp_t gfp)
1184 struct sk_buff *skb;
1186 skb = __mptcp_do_alloc_tx_skb(sk, gfp);
1190 if (likely(sk_wmem_schedule(ssk, skb->truesize))) {
1191 tcp_skb_entail(ssk, skb);
1194 tcp_skb_tsorted_anchor_cleanup(skb);
1199 static struct sk_buff *mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, bool data_lock_held)
1201 gfp_t gfp = data_lock_held ? GFP_ATOMIC : sk->sk_allocation;
1203 return __mptcp_alloc_tx_skb(sk, ssk, gfp);
1206 /* note: this always recompute the csum on the whole skb, even
1207 * if we just appended a single frag. More status info needed
1209 static void mptcp_update_data_checksum(struct sk_buff *skb, int added)
1211 struct mptcp_ext *mpext = mptcp_get_ext(skb);
1212 __wsum csum = ~csum_unfold(mpext->csum);
1213 int offset = skb->len - added;
1215 mpext->csum = csum_fold(csum_block_add(csum, skb_checksum(skb, offset, added, 0), offset));
1218 static void mptcp_update_infinite_map(struct mptcp_sock *msk,
1220 struct mptcp_ext *mpext)
1225 mpext->infinite_map = 1;
1226 mpext->data_len = 0;
1228 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPTX);
1229 mptcp_subflow_ctx(ssk)->send_infinite_map = 0;
1231 mptcp_do_fallback(ssk);
1234 static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
1235 struct mptcp_data_frag *dfrag,
1236 struct mptcp_sendmsg_info *info)
1238 u64 data_seq = dfrag->data_seq + info->sent;
1239 int offset = dfrag->offset + info->sent;
1240 struct mptcp_sock *msk = mptcp_sk(sk);
1241 bool zero_window_probe = false;
1242 struct mptcp_ext *mpext = NULL;
1243 bool can_coalesce = false;
1244 bool reuse_skb = true;
1245 struct sk_buff *skb;
1249 pr_debug("msk=%p ssk=%p sending dfrag at seq=%llu len=%u already sent=%u",
1250 msk, ssk, dfrag->data_seq, dfrag->data_len, info->sent);
1252 if (WARN_ON_ONCE(info->sent > info->limit ||
1253 info->limit > dfrag->data_len))
1256 if (unlikely(!__tcp_can_send(ssk)))
1259 /* compute send limit */
1260 info->mss_now = tcp_send_mss(ssk, &info->size_goal, info->flags);
1261 copy = info->size_goal;
1263 skb = tcp_write_queue_tail(ssk);
1264 if (skb && copy > skb->len) {
1265 /* Limit the write to the size available in the
1266 * current skb, if any, so that we create at most a new skb.
1267 * Explicitly tells TCP internals to avoid collapsing on later
1268 * queue management operation, to avoid breaking the ext <->
1269 * SSN association set here
1271 mpext = skb_ext_find(skb, SKB_EXT_MPTCP);
1272 if (!mptcp_skb_can_collapse_to(data_seq, skb, mpext)) {
1273 TCP_SKB_CB(skb)->eor = 1;
1277 i = skb_shinfo(skb)->nr_frags;
1278 can_coalesce = skb_can_coalesce(skb, i, dfrag->page, offset);
1279 if (!can_coalesce && i >= READ_ONCE(sysctl_max_skb_frags)) {
1280 tcp_mark_push(tcp_sk(ssk), skb);
1287 skb = mptcp_alloc_tx_skb(sk, ssk, info->data_lock_held);
1291 i = skb_shinfo(skb)->nr_frags;
1293 mpext = skb_ext_find(skb, SKB_EXT_MPTCP);
1296 /* Zero window and all data acked? Probe. */
1297 copy = mptcp_check_allowed_size(msk, ssk, data_seq, copy);
1299 u64 snd_una = READ_ONCE(msk->snd_una);
1301 if (snd_una != msk->snd_nxt) {
1302 tcp_remove_empty_skb(ssk);
1306 zero_window_probe = true;
1307 data_seq = snd_una - 1;
1310 /* all mptcp-level data is acked, no skbs should be present into the
1313 WARN_ON_ONCE(reuse_skb);
1316 copy = min_t(size_t, copy, info->limit - info->sent);
1317 if (!sk_wmem_schedule(ssk, copy)) {
1318 tcp_remove_empty_skb(ssk);
1323 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1325 get_page(dfrag->page);
1326 skb_fill_page_desc(skb, i, dfrag->page, offset, copy);
1330 skb->data_len += copy;
1331 skb->truesize += copy;
1332 sk_wmem_queued_add(ssk, copy);
1333 sk_mem_charge(ssk, copy);
1334 WRITE_ONCE(tcp_sk(ssk)->write_seq, tcp_sk(ssk)->write_seq + copy);
1335 TCP_SKB_CB(skb)->end_seq += copy;
1336 tcp_skb_pcount_set(skb, 0);
1338 /* on skb reuse we just need to update the DSS len */
1340 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1341 mpext->data_len += copy;
1342 WARN_ON_ONCE(zero_window_probe);
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 = copy;
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 += copy;
1360 if (READ_ONCE(msk->csum_enabled))
1361 mptcp_update_data_checksum(skb, copy);
1362 tcp_push_pending_frames(ssk);
1366 if (READ_ONCE(msk->csum_enabled))
1367 mptcp_update_data_checksum(skb, copy);
1368 if (mptcp_subflow_ctx(ssk)->send_infinite_map)
1369 mptcp_update_infinite_map(msk, ssk, mpext);
1370 trace_mptcp_sendmsg_frag(mpext);
1371 mptcp_subflow_ctx(ssk)->rel_write_seq += copy;
1375 #define MPTCP_SEND_BURST_SIZE ((1 << 16) - \
1376 sizeof(struct tcphdr) - \
1377 MAX_TCP_OPTION_SPACE - \
1378 sizeof(struct ipv6hdr) - \
1379 sizeof(struct frag_hdr))
1381 struct subflow_send_info {
1386 void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow)
1388 if (!subflow->stale)
1392 MPTCP_INC_STATS(sock_net(mptcp_subflow_tcp_sock(subflow)), MPTCP_MIB_SUBFLOWRECOVER);
1395 bool mptcp_subflow_active(struct mptcp_subflow_context *subflow)
1397 if (unlikely(subflow->stale)) {
1398 u32 rcv_tstamp = READ_ONCE(tcp_sk(mptcp_subflow_tcp_sock(subflow))->rcv_tstamp);
1400 if (subflow->stale_rcv_tstamp == rcv_tstamp)
1403 mptcp_subflow_set_active(subflow);
1405 return __mptcp_subflow_active(subflow);
1408 #define SSK_MODE_ACTIVE 0
1409 #define SSK_MODE_BACKUP 1
1410 #define SSK_MODE_MAX 2
1412 /* implement the mptcp packet scheduler;
1413 * returns the subflow that will transmit the next DSS
1414 * additionally updates the rtx timeout
1416 static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk)
1418 struct subflow_send_info send_info[SSK_MODE_MAX];
1419 struct mptcp_subflow_context *subflow;
1420 struct sock *sk = (struct sock *)msk;
1421 u32 pace, burst, wmem;
1422 int i, nr_active = 0;
1427 sock_owned_by_me(sk);
1429 if (__mptcp_check_fallback(msk)) {
1432 return __tcp_can_send(msk->first) &&
1433 sk_stream_memory_free(msk->first) ? msk->first : NULL;
1436 /* re-use last subflow, if the burst allow that */
1437 if (msk->last_snd && msk->snd_burst > 0 &&
1438 sk_stream_memory_free(msk->last_snd) &&
1439 mptcp_subflow_active(mptcp_subflow_ctx(msk->last_snd))) {
1440 mptcp_set_timeout(sk);
1441 return msk->last_snd;
1444 /* pick the subflow with the lower wmem/wspace ratio */
1445 for (i = 0; i < SSK_MODE_MAX; ++i) {
1446 send_info[i].ssk = NULL;
1447 send_info[i].linger_time = -1;
1450 mptcp_for_each_subflow(msk, subflow) {
1451 trace_mptcp_subflow_get_send(subflow);
1452 ssk = mptcp_subflow_tcp_sock(subflow);
1453 if (!mptcp_subflow_active(subflow))
1456 tout = max(tout, mptcp_timeout_from_subflow(subflow));
1457 nr_active += !subflow->backup;
1458 pace = subflow->avg_pacing_rate;
1459 if (unlikely(!pace)) {
1460 /* init pacing rate from socket */
1461 subflow->avg_pacing_rate = READ_ONCE(ssk->sk_pacing_rate);
1462 pace = subflow->avg_pacing_rate;
1467 linger_time = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32, pace);
1468 if (linger_time < send_info[subflow->backup].linger_time) {
1469 send_info[subflow->backup].ssk = ssk;
1470 send_info[subflow->backup].linger_time = linger_time;
1473 __mptcp_set_timeout(sk, tout);
1475 /* pick the best backup if no other subflow is active */
1477 send_info[SSK_MODE_ACTIVE].ssk = send_info[SSK_MODE_BACKUP].ssk;
1479 /* According to the blest algorithm, to avoid HoL blocking for the
1480 * faster flow, we need to:
1481 * - estimate the faster flow linger time
1482 * - use the above to estimate the amount of byte transferred
1483 * by the faster flow
1484 * - check that the amount of queued data is greter than the above,
1485 * otherwise do not use the picked, slower, subflow
1486 * We select the subflow with the shorter estimated time to flush
1487 * the queued mem, which basically ensure the above. We just need
1488 * to check that subflow has a non empty cwin.
1490 ssk = send_info[SSK_MODE_ACTIVE].ssk;
1491 if (!ssk || !sk_stream_memory_free(ssk))
1494 burst = min_t(int, MPTCP_SEND_BURST_SIZE, mptcp_wnd_end(msk) - msk->snd_nxt);
1495 wmem = READ_ONCE(ssk->sk_wmem_queued);
1497 msk->last_snd = NULL;
1501 subflow = mptcp_subflow_ctx(ssk);
1502 subflow->avg_pacing_rate = div_u64((u64)subflow->avg_pacing_rate * wmem +
1503 READ_ONCE(ssk->sk_pacing_rate) * burst,
1505 msk->last_snd = ssk;
1506 msk->snd_burst = burst;
1510 static void mptcp_push_release(struct sock *ssk, struct mptcp_sendmsg_info *info)
1512 tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal);
1516 static void mptcp_update_post_push(struct mptcp_sock *msk,
1517 struct mptcp_data_frag *dfrag,
1520 u64 snd_nxt_new = dfrag->data_seq;
1522 dfrag->already_sent += sent;
1524 msk->snd_burst -= sent;
1526 snd_nxt_new += dfrag->already_sent;
1528 /* snd_nxt_new can be smaller than snd_nxt in case mptcp
1529 * is recovering after a failover. In that event, this re-sends
1532 * Thus compute snd_nxt_new candidate based on
1533 * the dfrag->data_seq that was sent and the data
1534 * that has been handed to the subflow for transmission
1535 * and skip update in case it was old dfrag.
1537 if (likely(after64(snd_nxt_new, msk->snd_nxt)))
1538 msk->snd_nxt = snd_nxt_new;
1541 void mptcp_check_and_set_pending(struct sock *sk)
1543 if (mptcp_send_head(sk))
1544 mptcp_sk(sk)->push_pending |= BIT(MPTCP_PUSH_PENDING);
1547 void __mptcp_push_pending(struct sock *sk, unsigned int flags)
1549 struct sock *prev_ssk = NULL, *ssk = NULL;
1550 struct mptcp_sock *msk = mptcp_sk(sk);
1551 struct mptcp_sendmsg_info info = {
1554 bool do_check_data_fin = false;
1555 struct mptcp_data_frag *dfrag;
1558 while ((dfrag = mptcp_send_head(sk))) {
1559 info.sent = dfrag->already_sent;
1560 info.limit = dfrag->data_len;
1561 len = dfrag->data_len - dfrag->already_sent;
1566 ssk = mptcp_subflow_get_send(msk);
1568 /* First check. If the ssk has changed since
1569 * the last round, release prev_ssk
1571 if (ssk != prev_ssk && prev_ssk)
1572 mptcp_push_release(prev_ssk, &info);
1576 /* Need to lock the new subflow only if different
1577 * from the previous one, otherwise we are still
1578 * helding the relevant lock
1580 if (ssk != prev_ssk)
1583 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
1587 mptcp_push_release(ssk, &info);
1591 do_check_data_fin = true;
1595 mptcp_update_post_push(msk, dfrag, ret);
1597 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1600 /* at this point we held the socket lock for the last subflow we used */
1602 mptcp_push_release(ssk, &info);
1605 /* ensure the rtx timer is running */
1606 if (!mptcp_timer_pending(sk))
1607 mptcp_reset_timer(sk);
1608 if (do_check_data_fin)
1609 __mptcp_check_send_data_fin(sk);
1612 static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk)
1614 struct mptcp_sock *msk = mptcp_sk(sk);
1615 struct mptcp_sendmsg_info info = {
1616 .data_lock_held = true,
1618 struct mptcp_data_frag *dfrag;
1619 struct sock *xmit_ssk;
1620 int len, copied = 0;
1624 while ((dfrag = mptcp_send_head(sk))) {
1625 info.sent = dfrag->already_sent;
1626 info.limit = dfrag->data_len;
1627 len = dfrag->data_len - dfrag->already_sent;
1631 /* the caller already invoked the packet scheduler,
1632 * check for a different subflow usage only after
1633 * spooling the first chunk of data
1635 xmit_ssk = first ? ssk : mptcp_subflow_get_send(mptcp_sk(sk));
1638 if (xmit_ssk != ssk) {
1639 mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk),
1640 MPTCP_DELEGATE_SEND);
1644 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
1653 mptcp_update_post_push(msk, dfrag, ret);
1655 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
1659 /* __mptcp_alloc_tx_skb could have released some wmem and we are
1660 * not going to flush it via release_sock()
1663 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
1665 if (!mptcp_timer_pending(sk))
1666 mptcp_reset_timer(sk);
1668 if (msk->snd_data_fin_enable &&
1669 msk->snd_nxt + 1 == msk->write_seq)
1670 mptcp_schedule_work(sk);
1674 static void mptcp_set_nospace(struct sock *sk)
1676 /* enable autotune */
1677 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1679 /* will be cleared on avail space */
1680 set_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags);
1683 static int mptcp_disconnect(struct sock *sk, int flags);
1685 static int mptcp_sendmsg_fastopen(struct sock *sk, struct sock *ssk, struct msghdr *msg,
1686 size_t len, int *copied_syn)
1688 unsigned int saved_flags = msg->msg_flags;
1689 struct mptcp_sock *msk = mptcp_sk(sk);
1693 msg->msg_flags |= MSG_DONTWAIT;
1694 msk->fastopening = 1;
1695 ret = tcp_sendmsg_fastopen(ssk, msg, copied_syn, len, NULL);
1696 msk->fastopening = 0;
1697 msg->msg_flags = saved_flags;
1700 /* do the blocking bits of inet_stream_connect outside the ssk socket lock */
1701 if (ret == -EINPROGRESS && !(msg->msg_flags & MSG_DONTWAIT)) {
1702 ret = __inet_stream_connect(sk->sk_socket, msg->msg_name,
1703 msg->msg_namelen, msg->msg_flags, 1);
1705 /* Keep the same behaviour of plain TCP: zero the copied bytes in
1706 * case of any error, except timeout or signal
1708 if (ret && ret != -EINPROGRESS && ret != -ERESTARTSYS && ret != -EINTR)
1710 } else if (ret && ret != -EINPROGRESS) {
1711 mptcp_disconnect(sk, 0);
1717 static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
1719 struct mptcp_sock *msk = mptcp_sk(sk);
1720 struct page_frag *pfrag;
1721 struct socket *ssock;
1726 /* we don't support FASTOPEN yet */
1727 if (msg->msg_flags & MSG_FASTOPEN)
1730 /* silently ignore everything else */
1731 msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL;
1735 ssock = __mptcp_nmpc_socket(msk);
1736 if (unlikely(ssock && inet_sk(ssock->sk)->defer_connect)) {
1739 ret = mptcp_sendmsg_fastopen(sk, ssock->sk, msg, len, &copied_syn);
1740 copied += copied_syn;
1741 if (ret == -EINPROGRESS && copied_syn > 0)
1747 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1749 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
1750 ret = sk_stream_wait_connect(sk, &timeo);
1756 if (unlikely(sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)))
1759 pfrag = sk_page_frag(sk);
1761 while (msg_data_left(msg)) {
1762 int total_ts, frag_truesize = 0;
1763 struct mptcp_data_frag *dfrag;
1764 bool dfrag_collapsed;
1765 size_t psize, offset;
1767 /* reuse tail pfrag, if possible, or carve a new one from the
1770 dfrag = mptcp_pending_tail(sk);
1771 dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag);
1772 if (!dfrag_collapsed) {
1773 if (!sk_stream_memory_free(sk))
1774 goto wait_for_memory;
1776 if (!mptcp_page_frag_refill(sk, pfrag))
1777 goto wait_for_memory;
1779 dfrag = mptcp_carve_data_frag(msk, pfrag, pfrag->offset);
1780 frag_truesize = dfrag->overhead;
1783 /* we do not bound vs wspace, to allow a single packet.
1784 * memory accounting will prevent execessive memory usage
1787 offset = dfrag->offset + dfrag->data_len;
1788 psize = pfrag->size - offset;
1789 psize = min_t(size_t, psize, msg_data_left(msg));
1790 total_ts = psize + frag_truesize;
1792 if (!sk_wmem_schedule(sk, total_ts))
1793 goto wait_for_memory;
1795 if (copy_page_from_iter(dfrag->page, offset, psize,
1796 &msg->msg_iter) != psize) {
1801 /* data successfully copied into the write queue */
1802 sk->sk_forward_alloc -= total_ts;
1804 dfrag->data_len += psize;
1805 frag_truesize += psize;
1806 pfrag->offset += frag_truesize;
1807 WRITE_ONCE(msk->write_seq, msk->write_seq + psize);
1809 /* charge data on mptcp pending queue to the msk socket
1810 * Note: we charge such data both to sk and ssk
1812 sk_wmem_queued_add(sk, frag_truesize);
1813 if (!dfrag_collapsed) {
1814 get_page(dfrag->page);
1815 list_add_tail(&dfrag->list, &msk->rtx_queue);
1816 if (!msk->first_pending)
1817 WRITE_ONCE(msk->first_pending, dfrag);
1819 pr_debug("msk=%p dfrag at seq=%llu len=%u sent=%u new=%d", msk,
1820 dfrag->data_seq, dfrag->data_len, dfrag->already_sent,
1826 mptcp_set_nospace(sk);
1827 __mptcp_push_pending(sk, msg->msg_flags);
1828 ret = sk_stream_wait_memory(sk, &timeo);
1834 __mptcp_push_pending(sk, msg->msg_flags);
1844 copied = sk_stream_error(sk, msg->msg_flags, ret);
1848 static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk,
1850 size_t len, int flags,
1851 struct scm_timestamping_internal *tss,
1854 struct sk_buff *skb, *tmp;
1857 skb_queue_walk_safe(&msk->receive_queue, skb, tmp) {
1858 u32 offset = MPTCP_SKB_CB(skb)->offset;
1859 u32 data_len = skb->len - offset;
1860 u32 count = min_t(size_t, len - copied, data_len);
1863 if (!(flags & MSG_TRUNC)) {
1864 err = skb_copy_datagram_msg(skb, offset, msg, count);
1865 if (unlikely(err < 0)) {
1872 if (MPTCP_SKB_CB(skb)->has_rxtstamp) {
1873 tcp_update_recv_tstamps(skb, tss);
1874 *cmsg_flags |= MPTCP_CMSG_TS;
1879 if (count < data_len) {
1880 if (!(flags & MSG_PEEK)) {
1881 MPTCP_SKB_CB(skb)->offset += count;
1882 MPTCP_SKB_CB(skb)->map_seq += count;
1887 if (!(flags & MSG_PEEK)) {
1888 /* we will bulk release the skb memory later */
1889 skb->destructor = NULL;
1890 WRITE_ONCE(msk->rmem_released, msk->rmem_released + skb->truesize);
1891 __skb_unlink(skb, &msk->receive_queue);
1902 /* receive buffer autotuning. See tcp_rcv_space_adjust for more information.
1904 * Only difference: Use highest rtt estimate of the subflows in use.
1906 static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied)
1908 struct mptcp_subflow_context *subflow;
1909 struct sock *sk = (struct sock *)msk;
1910 u32 time, advmss = 1;
1913 sock_owned_by_me(sk);
1918 msk->rcvq_space.copied += copied;
1920 mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC);
1921 time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time);
1923 rtt_us = msk->rcvq_space.rtt_us;
1924 if (rtt_us && time < (rtt_us >> 3))
1928 mptcp_for_each_subflow(msk, subflow) {
1929 const struct tcp_sock *tp;
1933 tp = tcp_sk(mptcp_subflow_tcp_sock(subflow));
1935 sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us);
1936 sf_advmss = READ_ONCE(tp->advmss);
1938 rtt_us = max(sf_rtt_us, rtt_us);
1939 advmss = max(sf_advmss, advmss);
1942 msk->rcvq_space.rtt_us = rtt_us;
1943 if (time < (rtt_us >> 3) || rtt_us == 0)
1946 if (msk->rcvq_space.copied <= msk->rcvq_space.space)
1949 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf) &&
1950 !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
1954 rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss;
1956 grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space);
1958 do_div(grow, msk->rcvq_space.space);
1959 rcvwin += (grow << 1);
1961 rcvmem = SKB_TRUESIZE(advmss + MAX_TCP_HEADER);
1962 while (tcp_win_from_space(sk, rcvmem) < advmss)
1965 do_div(rcvwin, advmss);
1966 rcvbuf = min_t(u64, rcvwin * rcvmem,
1967 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[2]));
1969 if (rcvbuf > sk->sk_rcvbuf) {
1972 window_clamp = tcp_win_from_space(sk, rcvbuf);
1973 WRITE_ONCE(sk->sk_rcvbuf, rcvbuf);
1975 /* Make subflows follow along. If we do not do this, we
1976 * get drops at subflow level if skbs can't be moved to
1977 * the mptcp rx queue fast enough (announced rcv_win can
1978 * exceed ssk->sk_rcvbuf).
1980 mptcp_for_each_subflow(msk, subflow) {
1984 ssk = mptcp_subflow_tcp_sock(subflow);
1985 slow = lock_sock_fast(ssk);
1986 WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf);
1987 tcp_sk(ssk)->window_clamp = window_clamp;
1988 tcp_cleanup_rbuf(ssk, 1);
1989 unlock_sock_fast(ssk, slow);
1994 msk->rcvq_space.space = msk->rcvq_space.copied;
1996 msk->rcvq_space.copied = 0;
1997 msk->rcvq_space.time = mstamp;
2000 static void __mptcp_update_rmem(struct sock *sk)
2002 struct mptcp_sock *msk = mptcp_sk(sk);
2004 if (!msk->rmem_released)
2007 atomic_sub(msk->rmem_released, &sk->sk_rmem_alloc);
2008 mptcp_rmem_uncharge(sk, msk->rmem_released);
2009 WRITE_ONCE(msk->rmem_released, 0);
2012 static void __mptcp_splice_receive_queue(struct sock *sk)
2014 struct mptcp_sock *msk = mptcp_sk(sk);
2016 skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue);
2019 static bool __mptcp_move_skbs(struct mptcp_sock *msk)
2021 struct sock *sk = (struct sock *)msk;
2022 unsigned int moved = 0;
2026 struct sock *ssk = mptcp_subflow_recv_lookup(msk);
2029 /* we can have data pending in the subflows only if the msk
2030 * receive buffer was full at subflow_data_ready() time,
2031 * that is an unlikely slow path.
2036 slowpath = lock_sock_fast(ssk);
2037 mptcp_data_lock(sk);
2038 __mptcp_update_rmem(sk);
2039 done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
2040 mptcp_data_unlock(sk);
2042 if (unlikely(ssk->sk_err))
2043 __mptcp_error_report(sk);
2044 unlock_sock_fast(ssk, slowpath);
2047 /* acquire the data lock only if some input data is pending */
2049 if (!RB_EMPTY_ROOT(&msk->out_of_order_queue) ||
2050 !skb_queue_empty_lockless(&sk->sk_receive_queue)) {
2051 mptcp_data_lock(sk);
2052 __mptcp_update_rmem(sk);
2053 ret |= __mptcp_ofo_queue(msk);
2054 __mptcp_splice_receive_queue(sk);
2055 mptcp_data_unlock(sk);
2058 mptcp_check_data_fin((struct sock *)msk);
2059 return !skb_queue_empty(&msk->receive_queue);
2062 static unsigned int mptcp_inq_hint(const struct sock *sk)
2064 const struct mptcp_sock *msk = mptcp_sk(sk);
2065 const struct sk_buff *skb;
2067 skb = skb_peek(&msk->receive_queue);
2069 u64 hint_val = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq;
2071 if (hint_val >= INT_MAX)
2074 return (unsigned int)hint_val;
2077 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
2083 static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
2084 int flags, int *addr_len)
2086 struct mptcp_sock *msk = mptcp_sk(sk);
2087 struct scm_timestamping_internal tss;
2088 int copied = 0, cmsg_flags = 0;
2092 /* MSG_ERRQUEUE is really a no-op till we support IP_RECVERR */
2093 if (unlikely(flags & MSG_ERRQUEUE))
2094 return inet_recv_error(sk, msg, len, addr_len);
2097 if (unlikely(sk->sk_state == TCP_LISTEN)) {
2102 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2104 len = min_t(size_t, len, INT_MAX);
2105 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
2107 if (unlikely(msk->recvmsg_inq))
2108 cmsg_flags = MPTCP_CMSG_INQ;
2110 while (copied < len) {
2113 bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags, &tss, &cmsg_flags);
2114 if (unlikely(bytes_read < 0)) {
2116 copied = bytes_read;
2120 copied += bytes_read;
2122 /* be sure to advertise window change */
2123 mptcp_cleanup_rbuf(msk);
2125 if (skb_queue_empty(&msk->receive_queue) && __mptcp_move_skbs(msk))
2128 /* only the master socket status is relevant here. The exit
2129 * conditions mirror closely tcp_recvmsg()
2131 if (copied >= target)
2136 sk->sk_state == TCP_CLOSE ||
2137 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2139 signal_pending(current))
2143 copied = sock_error(sk);
2147 if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
2148 mptcp_check_for_eof(msk);
2150 if (sk->sk_shutdown & RCV_SHUTDOWN) {
2151 /* race breaker: the shutdown could be after the
2152 * previous receive queue check
2154 if (__mptcp_move_skbs(msk))
2159 if (sk->sk_state == TCP_CLOSE) {
2169 if (signal_pending(current)) {
2170 copied = sock_intr_errno(timeo);
2175 pr_debug("block timeout %ld", timeo);
2176 sk_wait_data(sk, &timeo, NULL);
2180 if (cmsg_flags && copied >= 0) {
2181 if (cmsg_flags & MPTCP_CMSG_TS)
2182 tcp_recv_timestamp(msg, sk, &tss);
2184 if (cmsg_flags & MPTCP_CMSG_INQ) {
2185 unsigned int inq = mptcp_inq_hint(sk);
2187 put_cmsg(msg, SOL_TCP, TCP_CM_INQ, sizeof(inq), &inq);
2191 pr_debug("msk=%p rx queue empty=%d:%d copied=%d",
2192 msk, skb_queue_empty_lockless(&sk->sk_receive_queue),
2193 skb_queue_empty(&msk->receive_queue), copied);
2194 if (!(flags & MSG_PEEK))
2195 mptcp_rcv_space_adjust(msk, copied);
2201 static void mptcp_retransmit_timer(struct timer_list *t)
2203 struct inet_connection_sock *icsk = from_timer(icsk, t,
2204 icsk_retransmit_timer);
2205 struct sock *sk = &icsk->icsk_inet.sk;
2206 struct mptcp_sock *msk = mptcp_sk(sk);
2209 if (!sock_owned_by_user(sk)) {
2210 /* we need a process context to retransmit */
2211 if (!test_and_set_bit(MPTCP_WORK_RTX, &msk->flags))
2212 mptcp_schedule_work(sk);
2214 /* delegate our work to tcp_release_cb() */
2215 __set_bit(MPTCP_RETRANSMIT, &msk->cb_flags);
2221 static void mptcp_timeout_timer(struct timer_list *t)
2223 struct sock *sk = from_timer(sk, t, sk_timer);
2225 mptcp_schedule_work(sk);
2229 /* Find an idle subflow. Return NULL if there is unacked data at tcp
2232 * A backup subflow is returned only if that is the only kind available.
2234 static struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk)
2236 struct sock *backup = NULL, *pick = NULL;
2237 struct mptcp_subflow_context *subflow;
2238 int min_stale_count = INT_MAX;
2240 sock_owned_by_me((const struct sock *)msk);
2242 if (__mptcp_check_fallback(msk))
2245 mptcp_for_each_subflow(msk, subflow) {
2246 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2248 if (!__mptcp_subflow_active(subflow))
2251 /* still data outstanding at TCP level? skip this */
2252 if (!tcp_rtx_and_write_queues_empty(ssk)) {
2253 mptcp_pm_subflow_chk_stale(msk, ssk);
2254 min_stale_count = min_t(int, min_stale_count, subflow->stale_count);
2258 if (subflow->backup) {
2271 /* use backup only if there are no progresses anywhere */
2272 return min_stale_count > 1 ? backup : NULL;
2275 static void mptcp_dispose_initial_subflow(struct mptcp_sock *msk)
2278 iput(SOCK_INODE(msk->subflow));
2279 WRITE_ONCE(msk->subflow, NULL);
2283 bool __mptcp_retransmit_pending_data(struct sock *sk)
2285 struct mptcp_data_frag *cur, *rtx_head;
2286 struct mptcp_sock *msk = mptcp_sk(sk);
2288 if (__mptcp_check_fallback(mptcp_sk(sk)))
2291 if (tcp_rtx_and_write_queues_empty(sk))
2294 /* the closing socket has some data untransmitted and/or unacked:
2295 * some data in the mptcp rtx queue has not really xmitted yet.
2296 * keep it simple and re-inject the whole mptcp level rtx queue
2298 mptcp_data_lock(sk);
2299 __mptcp_clean_una_wakeup(sk);
2300 rtx_head = mptcp_rtx_head(sk);
2302 mptcp_data_unlock(sk);
2306 msk->recovery_snd_nxt = msk->snd_nxt;
2307 msk->recovery = true;
2308 mptcp_data_unlock(sk);
2310 msk->first_pending = rtx_head;
2313 /* be sure to clear the "sent status" on all re-injected fragments */
2314 list_for_each_entry(cur, &msk->rtx_queue, list) {
2315 if (!cur->already_sent)
2317 cur->already_sent = 0;
2323 /* flags for __mptcp_close_ssk() */
2324 #define MPTCP_CF_PUSH BIT(1)
2325 #define MPTCP_CF_FASTCLOSE BIT(2)
2327 /* subflow sockets can be either outgoing (connect) or incoming
2330 * Outgoing subflows use in-kernel sockets.
2331 * Incoming subflows do not have their own 'struct socket' allocated,
2332 * so we need to use tcp_close() after detaching them from the mptcp
2335 static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
2336 struct mptcp_subflow_context *subflow,
2339 struct mptcp_sock *msk = mptcp_sk(sk);
2340 bool dispose_it, need_push = false;
2342 /* If the first subflow moved to a close state before accept, e.g. due
2343 * to an incoming reset, mptcp either:
2344 * - if either the subflow or the msk are dead, destroy the context
2345 * (the subflow socket is deleted by inet_child_forget) and the msk
2346 * - otherwise do nothing at the moment and take action at accept and/or
2347 * listener shutdown - user-space must be able to accept() the closed
2350 if (msk->in_accept_queue && msk->first == ssk) {
2351 if (!sock_flag(sk, SOCK_DEAD) && !sock_flag(ssk, SOCK_DEAD))
2354 /* ensure later check in mptcp_worker() will dispose the msk */
2355 sock_set_flag(sk, SOCK_DEAD);
2356 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
2357 mptcp_subflow_drop_ctx(ssk);
2361 dispose_it = !msk->subflow || ssk != msk->subflow->sk;
2363 list_del(&subflow->node);
2365 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
2367 if (flags & MPTCP_CF_FASTCLOSE) {
2368 /* be sure to force the tcp_disconnect() path,
2369 * to generate the egress reset
2371 ssk->sk_lingertime = 0;
2372 sock_set_flag(ssk, SOCK_LINGER);
2373 subflow->send_fastclose = 1;
2376 need_push = (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(sk);
2378 tcp_disconnect(ssk, 0);
2379 msk->subflow->state = SS_UNCONNECTED;
2380 mptcp_subflow_ctx_reset(subflow);
2386 subflow->disposable = 1;
2388 /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops
2389 * the ssk has been already destroyed, we just need to release the
2390 * reference owned by msk;
2392 if (!inet_csk(ssk)->icsk_ulp_ops) {
2393 WARN_ON_ONCE(!sock_flag(ssk, SOCK_DEAD));
2394 kfree_rcu(subflow, rcu);
2396 /* otherwise tcp will dispose of the ssk and subflow ctx */
2397 if (ssk->sk_state == TCP_LISTEN) {
2398 tcp_set_state(ssk, TCP_CLOSE);
2399 mptcp_subflow_queue_clean(sk, ssk);
2400 inet_csk_listen_stop(ssk);
2403 __tcp_close(ssk, 0);
2405 /* close acquired an extra ref */
2414 if (ssk == msk->first)
2415 WRITE_ONCE(msk->first, NULL);
2418 if (ssk == msk->last_snd)
2419 msk->last_snd = NULL;
2422 __mptcp_push_pending(sk, 0);
2425 void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
2426 struct mptcp_subflow_context *subflow)
2428 if (sk->sk_state == TCP_ESTABLISHED)
2429 mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL);
2431 /* subflow aborted before reaching the fully_established status
2432 * attempt the creation of the next subflow
2434 mptcp_pm_subflow_check_next(mptcp_sk(sk), ssk, subflow);
2436 __mptcp_close_ssk(sk, ssk, subflow, MPTCP_CF_PUSH);
2439 static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu)
2444 static void __mptcp_close_subflow(struct sock *sk)
2446 struct mptcp_subflow_context *subflow, *tmp;
2447 struct mptcp_sock *msk = mptcp_sk(sk);
2451 mptcp_for_each_subflow_safe(msk, subflow, tmp) {
2452 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2454 if (inet_sk_state_load(ssk) != TCP_CLOSE)
2457 /* 'subflow_data_ready' will re-sched once rx queue is empty */
2458 if (!skb_queue_empty_lockless(&ssk->sk_receive_queue))
2461 mptcp_close_ssk(sk, ssk, subflow);
2466 static bool mptcp_should_close(const struct sock *sk)
2468 s32 delta = tcp_jiffies32 - inet_csk(sk)->icsk_mtup.probe_timestamp;
2469 struct mptcp_subflow_context *subflow;
2471 if (delta >= TCP_TIMEWAIT_LEN || mptcp_sk(sk)->in_accept_queue)
2474 /* if all subflows are in closed status don't bother with additional
2477 mptcp_for_each_subflow(mptcp_sk(sk), subflow) {
2478 if (inet_sk_state_load(mptcp_subflow_tcp_sock(subflow)) !=
2485 static void mptcp_check_fastclose(struct mptcp_sock *msk)
2487 struct mptcp_subflow_context *subflow, *tmp;
2488 struct sock *sk = &msk->sk.icsk_inet.sk;
2490 if (likely(!READ_ONCE(msk->rcv_fastclose)))
2493 mptcp_token_destroy(msk);
2495 mptcp_for_each_subflow_safe(msk, subflow, tmp) {
2496 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
2499 slow = lock_sock_fast(tcp_sk);
2500 if (tcp_sk->sk_state != TCP_CLOSE) {
2501 tcp_send_active_reset(tcp_sk, GFP_ATOMIC);
2502 tcp_set_state(tcp_sk, TCP_CLOSE);
2504 unlock_sock_fast(tcp_sk, slow);
2507 /* Mirror the tcp_reset() error propagation */
2508 switch (sk->sk_state) {
2510 sk->sk_err = ECONNREFUSED;
2512 case TCP_CLOSE_WAIT:
2518 sk->sk_err = ECONNRESET;
2521 inet_sk_state_store(sk, TCP_CLOSE);
2522 WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
2523 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
2524 set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags);
2526 /* the calling mptcp_worker will properly destroy the socket */
2527 if (sock_flag(sk, SOCK_DEAD))
2530 sk->sk_state_change(sk);
2531 sk_error_report(sk);
2534 static void __mptcp_retrans(struct sock *sk)
2536 struct mptcp_sock *msk = mptcp_sk(sk);
2537 struct mptcp_sendmsg_info info = {};
2538 struct mptcp_data_frag *dfrag;
2543 mptcp_clean_una_wakeup(sk);
2545 /* first check ssk: need to kick "stale" logic */
2546 ssk = mptcp_subflow_get_retrans(msk);
2547 dfrag = mptcp_rtx_head(sk);
2549 if (mptcp_data_fin_enabled(msk)) {
2550 struct inet_connection_sock *icsk = inet_csk(sk);
2552 icsk->icsk_retransmits++;
2553 mptcp_set_datafin_timeout(sk);
2554 mptcp_send_ack(msk);
2559 if (!mptcp_send_head(sk))
2570 /* limit retransmission to the bytes already sent on some subflows */
2572 info.limit = READ_ONCE(msk->csum_enabled) ? dfrag->data_len : dfrag->already_sent;
2573 while (info.sent < info.limit) {
2574 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
2578 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS);
2583 dfrag->already_sent = max(dfrag->already_sent, info.sent);
2584 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
2586 WRITE_ONCE(msk->allow_infinite_fallback, false);
2592 mptcp_check_and_set_pending(sk);
2594 if (!mptcp_timer_pending(sk))
2595 mptcp_reset_timer(sk);
2598 /* schedule the timeout timer for the relevant event: either close timeout
2599 * or mp_fail timeout. The close timeout takes precedence on the mp_fail one
2601 void mptcp_reset_timeout(struct mptcp_sock *msk, unsigned long fail_tout)
2603 struct sock *sk = (struct sock *)msk;
2604 unsigned long timeout, close_timeout;
2606 if (!fail_tout && !sock_flag(sk, SOCK_DEAD))
2609 close_timeout = inet_csk(sk)->icsk_mtup.probe_timestamp - tcp_jiffies32 + jiffies + TCP_TIMEWAIT_LEN;
2611 /* the close timeout takes precedence on the fail one, and here at least one of
2614 timeout = sock_flag(sk, SOCK_DEAD) ? close_timeout : fail_tout;
2616 sk_reset_timer(sk, &sk->sk_timer, timeout);
2619 static void mptcp_mp_fail_no_response(struct mptcp_sock *msk)
2621 struct sock *ssk = msk->first;
2627 pr_debug("MP_FAIL doesn't respond, reset the subflow");
2629 slow = lock_sock_fast(ssk);
2630 mptcp_subflow_reset(ssk);
2631 WRITE_ONCE(mptcp_subflow_ctx(ssk)->fail_tout, 0);
2632 unlock_sock_fast(ssk, slow);
2634 mptcp_reset_timeout(msk, 0);
2637 static void mptcp_do_fastclose(struct sock *sk)
2639 struct mptcp_subflow_context *subflow, *tmp;
2640 struct mptcp_sock *msk = mptcp_sk(sk);
2642 mptcp_for_each_subflow_safe(msk, subflow, tmp)
2643 __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow),
2644 subflow, MPTCP_CF_FASTCLOSE);
2647 static void mptcp_worker(struct work_struct *work)
2649 struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
2650 struct sock *sk = &msk->sk.icsk_inet.sk;
2651 unsigned long fail_tout;
2655 state = sk->sk_state;
2656 if (unlikely((1 << state) & (TCPF_CLOSE | TCPF_LISTEN)))
2659 mptcp_check_data_fin_ack(sk);
2661 mptcp_check_fastclose(msk);
2663 mptcp_pm_nl_work(msk);
2665 if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
2666 mptcp_check_for_eof(msk);
2668 __mptcp_check_send_data_fin(sk);
2669 mptcp_check_data_fin(sk);
2671 if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
2672 __mptcp_close_subflow(sk);
2674 /* There is no point in keeping around an orphaned sk timedout or
2675 * closed, but we need the msk around to reply to incoming DATA_FIN,
2676 * even if it is orphaned and in FIN_WAIT2 state
2678 if (sock_flag(sk, SOCK_DEAD)) {
2679 if (mptcp_should_close(sk)) {
2680 inet_sk_state_store(sk, TCP_CLOSE);
2681 mptcp_do_fastclose(sk);
2683 if (sk->sk_state == TCP_CLOSE) {
2684 __mptcp_destroy_sock(sk);
2689 if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
2690 __mptcp_retrans(sk);
2692 fail_tout = msk->first ? READ_ONCE(mptcp_subflow_ctx(msk->first)->fail_tout) : 0;
2693 if (fail_tout && time_after(jiffies, fail_tout))
2694 mptcp_mp_fail_no_response(msk);
2701 static int __mptcp_init_sock(struct sock *sk)
2703 struct mptcp_sock *msk = mptcp_sk(sk);
2705 INIT_LIST_HEAD(&msk->conn_list);
2706 INIT_LIST_HEAD(&msk->join_list);
2707 INIT_LIST_HEAD(&msk->rtx_queue);
2708 INIT_WORK(&msk->work, mptcp_worker);
2709 __skb_queue_head_init(&msk->receive_queue);
2710 msk->out_of_order_queue = RB_ROOT;
2711 msk->first_pending = NULL;
2712 msk->rmem_fwd_alloc = 0;
2713 WRITE_ONCE(msk->rmem_released, 0);
2714 msk->timer_ival = TCP_RTO_MIN;
2716 WRITE_ONCE(msk->first, NULL);
2717 inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss;
2718 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
2719 WRITE_ONCE(msk->allow_infinite_fallback, true);
2720 msk->recovery = false;
2722 mptcp_pm_data_init(msk);
2724 /* re-use the csk retrans timer for MPTCP-level retrans */
2725 timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0);
2726 timer_setup(&sk->sk_timer, mptcp_timeout_timer, 0);
2731 static void mptcp_ca_reset(struct sock *sk)
2733 struct inet_connection_sock *icsk = inet_csk(sk);
2735 tcp_assign_congestion_control(sk);
2736 strcpy(mptcp_sk(sk)->ca_name, icsk->icsk_ca_ops->name);
2738 /* no need to keep a reference to the ops, the name will suffice */
2739 tcp_cleanup_congestion_control(sk);
2740 icsk->icsk_ca_ops = NULL;
2743 static int mptcp_init_sock(struct sock *sk)
2745 struct net *net = sock_net(sk);
2748 ret = __mptcp_init_sock(sk);
2752 if (!mptcp_is_enabled(net))
2753 return -ENOPROTOOPT;
2755 if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net))
2758 ret = __mptcp_socket_create(mptcp_sk(sk));
2762 /* fetch the ca name; do it outside __mptcp_init_sock(), so that clone will
2763 * propagate the correct value
2767 sk_sockets_allocated_inc(sk);
2768 sk->sk_rcvbuf = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[1]);
2769 sk->sk_sndbuf = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[1]);
2774 static void __mptcp_clear_xmit(struct sock *sk)
2776 struct mptcp_sock *msk = mptcp_sk(sk);
2777 struct mptcp_data_frag *dtmp, *dfrag;
2779 WRITE_ONCE(msk->first_pending, NULL);
2780 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list)
2781 dfrag_clear(sk, dfrag);
2784 void mptcp_cancel_work(struct sock *sk)
2786 struct mptcp_sock *msk = mptcp_sk(sk);
2788 if (cancel_work_sync(&msk->work))
2792 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how)
2796 switch (ssk->sk_state) {
2798 if (!(how & RCV_SHUTDOWN))
2802 tcp_disconnect(ssk, O_NONBLOCK);
2805 if (__mptcp_check_fallback(mptcp_sk(sk))) {
2806 pr_debug("Fallback");
2807 ssk->sk_shutdown |= how;
2808 tcp_shutdown(ssk, how);
2810 pr_debug("Sending DATA_FIN on subflow %p", ssk);
2812 if (!mptcp_timer_pending(sk))
2813 mptcp_reset_timer(sk);
2821 static const unsigned char new_state[16] = {
2822 /* current state: new state: action: */
2823 [0 /* (Invalid) */] = TCP_CLOSE,
2824 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2825 [TCP_SYN_SENT] = TCP_CLOSE,
2826 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2827 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1,
2828 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2,
2829 [TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */
2830 [TCP_CLOSE] = TCP_CLOSE,
2831 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN,
2832 [TCP_LAST_ACK] = TCP_LAST_ACK,
2833 [TCP_LISTEN] = TCP_CLOSE,
2834 [TCP_CLOSING] = TCP_CLOSING,
2835 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */
2838 static int mptcp_close_state(struct sock *sk)
2840 int next = (int)new_state[sk->sk_state];
2841 int ns = next & TCP_STATE_MASK;
2843 inet_sk_state_store(sk, ns);
2845 return next & TCP_ACTION_FIN;
2848 static void __mptcp_check_send_data_fin(struct sock *sk)
2850 struct mptcp_subflow_context *subflow;
2851 struct mptcp_sock *msk = mptcp_sk(sk);
2853 pr_debug("msk=%p snd_data_fin_enable=%d pending=%d snd_nxt=%llu write_seq=%llu",
2854 msk, msk->snd_data_fin_enable, !!mptcp_send_head(sk),
2855 msk->snd_nxt, msk->write_seq);
2857 /* we still need to enqueue subflows or not really shutting down,
2860 if (!msk->snd_data_fin_enable || msk->snd_nxt + 1 != msk->write_seq ||
2861 mptcp_send_head(sk))
2864 WRITE_ONCE(msk->snd_nxt, msk->write_seq);
2866 /* fallback socket will not get data_fin/ack, can move to the next
2869 if (__mptcp_check_fallback(msk)) {
2870 WRITE_ONCE(msk->snd_una, msk->write_seq);
2871 if ((1 << sk->sk_state) & (TCPF_CLOSING | TCPF_LAST_ACK)) {
2872 inet_sk_state_store(sk, TCP_CLOSE);
2873 mptcp_close_wake_up(sk);
2874 } else if (sk->sk_state == TCP_FIN_WAIT1) {
2875 inet_sk_state_store(sk, TCP_FIN_WAIT2);
2879 mptcp_for_each_subflow(msk, subflow) {
2880 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
2882 mptcp_subflow_shutdown(sk, tcp_sk, SEND_SHUTDOWN);
2886 static void __mptcp_wr_shutdown(struct sock *sk)
2888 struct mptcp_sock *msk = mptcp_sk(sk);
2890 pr_debug("msk=%p snd_data_fin_enable=%d shutdown=%x state=%d pending=%d",
2891 msk, msk->snd_data_fin_enable, sk->sk_shutdown, sk->sk_state,
2892 !!mptcp_send_head(sk));
2894 /* will be ignored by fallback sockets */
2895 WRITE_ONCE(msk->write_seq, msk->write_seq + 1);
2896 WRITE_ONCE(msk->snd_data_fin_enable, 1);
2898 __mptcp_check_send_data_fin(sk);
2901 static void __mptcp_destroy_sock(struct sock *sk)
2903 struct mptcp_sock *msk = mptcp_sk(sk);
2905 pr_debug("msk=%p", msk);
2909 mptcp_stop_timer(sk);
2910 sk_stop_timer(sk, &sk->sk_timer);
2913 sk->sk_prot->destroy(sk);
2915 WARN_ON_ONCE(msk->rmem_fwd_alloc);
2916 WARN_ON_ONCE(msk->rmem_released);
2917 sk_stream_kill_queues(sk);
2918 xfrm_sk_free_policy(sk);
2920 sk_refcnt_debug_release(sk);
2924 void __mptcp_unaccepted_force_close(struct sock *sk)
2926 sock_set_flag(sk, SOCK_DEAD);
2927 inet_sk_state_store(sk, TCP_CLOSE);
2928 mptcp_do_fastclose(sk);
2929 __mptcp_destroy_sock(sk);
2932 static __poll_t mptcp_check_readable(struct mptcp_sock *msk)
2934 /* Concurrent splices from sk_receive_queue into receive_queue will
2935 * always show at least one non-empty queue when checked in this order.
2937 if (skb_queue_empty_lockless(&((struct sock *)msk)->sk_receive_queue) &&
2938 skb_queue_empty_lockless(&msk->receive_queue))
2941 return EPOLLIN | EPOLLRDNORM;
2944 bool __mptcp_close(struct sock *sk, long timeout)
2946 struct mptcp_subflow_context *subflow;
2947 struct mptcp_sock *msk = mptcp_sk(sk);
2948 bool do_cancel_work = false;
2949 int subflows_alive = 0;
2951 WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
2953 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) {
2954 inet_sk_state_store(sk, TCP_CLOSE);
2958 if (mptcp_check_readable(msk)) {
2959 /* the msk has read data, do the MPTCP equivalent of TCP reset */
2960 inet_sk_state_store(sk, TCP_CLOSE);
2961 mptcp_do_fastclose(sk);
2962 } else if (mptcp_close_state(sk)) {
2963 __mptcp_wr_shutdown(sk);
2966 sk_stream_wait_close(sk, timeout);
2969 /* orphan all the subflows */
2970 inet_csk(sk)->icsk_mtup.probe_timestamp = tcp_jiffies32;
2971 mptcp_for_each_subflow(msk, subflow) {
2972 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
2973 bool slow = lock_sock_fast_nested(ssk);
2975 subflows_alive += ssk->sk_state != TCP_CLOSE;
2977 /* since the close timeout takes precedence on the fail one,
2980 if (ssk == msk->first)
2981 subflow->fail_tout = 0;
2983 /* detach from the parent socket, but allow data_ready to
2984 * push incoming data into the mptcp stack, to properly ack it
2986 ssk->sk_socket = NULL;
2988 unlock_sock_fast(ssk, slow);
2992 /* all the subflows are closed, only timeout can change the msk
2993 * state, let's not keep resources busy for no reasons
2995 if (subflows_alive == 0)
2996 inet_sk_state_store(sk, TCP_CLOSE);
2999 pr_debug("msk=%p state=%d", sk, sk->sk_state);
3000 if (mptcp_sk(sk)->token)
3001 mptcp_event(MPTCP_EVENT_CLOSED, msk, NULL, GFP_KERNEL);
3003 if (sk->sk_state == TCP_CLOSE) {
3004 __mptcp_destroy_sock(sk);
3005 do_cancel_work = true;
3007 mptcp_reset_timeout(msk, 0);
3010 return do_cancel_work;
3013 static void mptcp_close(struct sock *sk, long timeout)
3015 bool do_cancel_work;
3019 do_cancel_work = __mptcp_close(sk, timeout);
3022 mptcp_cancel_work(sk);
3027 static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk)
3029 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
3030 const struct ipv6_pinfo *ssk6 = inet6_sk(ssk);
3031 struct ipv6_pinfo *msk6 = inet6_sk(msk);
3033 msk->sk_v6_daddr = ssk->sk_v6_daddr;
3034 msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr;
3037 msk6->saddr = ssk6->saddr;
3038 msk6->flow_label = ssk6->flow_label;
3042 inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num;
3043 inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport;
3044 inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport;
3045 inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr;
3046 inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr;
3047 inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr;
3050 static int mptcp_disconnect(struct sock *sk, int flags)
3052 struct mptcp_sock *msk = mptcp_sk(sk);
3054 /* We are on the fastopen error path. We can't call straight into the
3055 * subflows cleanup code due to lock nesting (we are already under
3056 * msk->firstsocket lock). Do nothing and leave the cleanup to the
3059 if (msk->fastopening)
3062 inet_sk_state_store(sk, TCP_CLOSE);
3064 mptcp_stop_timer(sk);
3065 sk_stop_timer(sk, &sk->sk_timer);
3067 if (mptcp_sk(sk)->token)
3068 mptcp_event(MPTCP_EVENT_CLOSED, mptcp_sk(sk), NULL, GFP_KERNEL);
3070 /* msk->subflow is still intact, the following will not free the first
3073 mptcp_destroy_common(msk, MPTCP_CF_FASTCLOSE);
3074 msk->last_snd = NULL;
3075 WRITE_ONCE(msk->flags, 0);
3077 msk->push_pending = 0;
3078 msk->recovery = false;
3079 msk->can_ack = false;
3080 msk->fully_established = false;
3081 msk->rcv_data_fin = false;
3082 msk->snd_data_fin_enable = false;
3083 msk->rcv_fastclose = false;
3084 msk->use_64bit_ack = false;
3085 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
3086 mptcp_pm_data_reset(msk);
3089 WRITE_ONCE(sk->sk_shutdown, 0);
3090 sk_error_report(sk);
3094 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
3095 static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk)
3097 unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo);
3099 return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
3103 struct sock *mptcp_sk_clone_init(const struct sock *sk,
3104 const struct mptcp_options_received *mp_opt,
3106 struct request_sock *req)
3108 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
3109 struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC);
3110 struct mptcp_sock *msk;
3116 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
3117 if (nsk->sk_family == AF_INET6)
3118 inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk);
3121 __mptcp_init_sock(nsk);
3123 msk = mptcp_sk(nsk);
3124 msk->local_key = subflow_req->local_key;
3125 msk->token = subflow_req->token;
3126 WRITE_ONCE(msk->subflow, NULL);
3127 msk->in_accept_queue = 1;
3128 WRITE_ONCE(msk->fully_established, false);
3129 if (mp_opt->suboptions & OPTION_MPTCP_CSUMREQD)
3130 WRITE_ONCE(msk->csum_enabled, true);
3132 msk->write_seq = subflow_req->idsn + 1;
3133 msk->snd_nxt = msk->write_seq;
3134 msk->snd_una = msk->write_seq;
3135 msk->wnd_end = msk->snd_nxt + req->rsk_rcv_wnd;
3136 msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq;
3138 if (mp_opt->suboptions & OPTIONS_MPTCP_MPC) {
3139 msk->can_ack = true;
3140 msk->remote_key = mp_opt->sndr_key;
3141 mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq);
3143 WRITE_ONCE(msk->ack_seq, ack_seq);
3144 atomic64_set(&msk->rcv_wnd_sent, ack_seq);
3147 sock_reset_flag(nsk, SOCK_RCU_FREE);
3148 security_inet_csk_clone(nsk, req);
3150 /* this can't race with mptcp_close(), as the msk is
3151 * not yet exposted to user-space
3153 inet_sk_state_store(nsk, TCP_ESTABLISHED);
3155 /* The msk maintain a ref to each subflow in the connections list */
3156 WRITE_ONCE(msk->first, ssk);
3157 list_add(&mptcp_subflow_ctx(ssk)->node, &msk->conn_list);
3160 /* new mpc subflow takes ownership of the newly
3161 * created mptcp socket
3163 mptcp_token_accept(subflow_req, msk);
3165 /* set msk addresses early to ensure mptcp_pm_get_local_id()
3166 * uses the correct data
3168 mptcp_copy_inaddrs(nsk, ssk);
3169 mptcp_propagate_sndbuf(nsk, ssk);
3171 mptcp_rcv_space_init(msk, ssk);
3172 bh_unlock_sock(nsk);
3174 /* note: the newly allocated socket refcount is 2 now */
3178 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk)
3180 const struct tcp_sock *tp = tcp_sk(ssk);
3182 msk->rcvq_space.copied = 0;
3183 msk->rcvq_space.rtt_us = 0;
3185 msk->rcvq_space.time = tp->tcp_mstamp;
3187 /* initial rcv_space offering made to peer */
3188 msk->rcvq_space.space = min_t(u32, tp->rcv_wnd,
3189 TCP_INIT_CWND * tp->advmss);
3190 if (msk->rcvq_space.space == 0)
3191 msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT;
3193 WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd);
3196 static struct sock *mptcp_accept(struct sock *sk, int flags, int *err,
3199 struct mptcp_sock *msk = mptcp_sk(sk);
3200 struct socket *listener;
3203 listener = READ_ONCE(msk->subflow);
3204 if (WARN_ON_ONCE(!listener)) {
3209 pr_debug("msk=%p, listener=%p", msk, mptcp_subflow_ctx(listener->sk));
3210 newsk = inet_csk_accept(listener->sk, flags, err, kern);
3214 pr_debug("msk=%p, subflow is mptcp=%d", msk, sk_is_mptcp(newsk));
3215 if (sk_is_mptcp(newsk)) {
3216 struct mptcp_subflow_context *subflow;
3217 struct sock *new_mptcp_sock;
3219 subflow = mptcp_subflow_ctx(newsk);
3220 new_mptcp_sock = subflow->conn;
3222 /* is_mptcp should be false if subflow->conn is missing, see
3223 * subflow_syn_recv_sock()
3225 if (WARN_ON_ONCE(!new_mptcp_sock)) {
3226 tcp_sk(newsk)->is_mptcp = 0;
3230 newsk = new_mptcp_sock;
3231 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEPASSIVEACK);
3233 MPTCP_INC_STATS(sock_net(sk),
3234 MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK);
3238 newsk->sk_kern_sock = kern;
3242 void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags)
3244 struct mptcp_subflow_context *subflow, *tmp;
3245 struct sock *sk = (struct sock *)msk;
3247 __mptcp_clear_xmit(sk);
3249 /* join list will be eventually flushed (with rst) at sock lock release time */
3250 mptcp_for_each_subflow_safe(msk, subflow, tmp)
3251 __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), subflow, flags);
3253 /* move to sk_receive_queue, sk_stream_kill_queues will purge it */
3254 mptcp_data_lock(sk);
3255 skb_queue_splice_tail_init(&msk->receive_queue, &sk->sk_receive_queue);
3256 __skb_queue_purge(&sk->sk_receive_queue);
3257 skb_rbtree_purge(&msk->out_of_order_queue);
3258 mptcp_data_unlock(sk);
3260 /* move all the rx fwd alloc into the sk_mem_reclaim_final in
3261 * inet_sock_destruct() will dispose it
3263 sk->sk_forward_alloc += msk->rmem_fwd_alloc;
3264 msk->rmem_fwd_alloc = 0;
3265 mptcp_token_destroy(msk);
3266 mptcp_pm_free_anno_list(msk);
3267 mptcp_free_local_addr_list(msk);
3270 static void mptcp_destroy(struct sock *sk)
3272 struct mptcp_sock *msk = mptcp_sk(sk);
3274 /* clears msk->subflow, allowing the following to close
3275 * even the initial subflow
3277 mptcp_dispose_initial_subflow(msk);
3278 mptcp_destroy_common(msk, 0);
3279 sk_sockets_allocated_dec(sk);
3282 void __mptcp_data_acked(struct sock *sk)
3284 if (!sock_owned_by_user(sk))
3285 __mptcp_clean_una(sk);
3287 __set_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->cb_flags);
3289 if (mptcp_pending_data_fin_ack(sk))
3290 mptcp_schedule_work(sk);
3293 void __mptcp_check_push(struct sock *sk, struct sock *ssk)
3295 if (!mptcp_send_head(sk))
3298 if (!sock_owned_by_user(sk)) {
3299 struct sock *xmit_ssk = mptcp_subflow_get_send(mptcp_sk(sk));
3301 if (xmit_ssk == ssk)
3302 __mptcp_subflow_push_pending(sk, ssk);
3304 mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk), MPTCP_DELEGATE_SEND);
3306 __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags);
3310 #define MPTCP_FLAGS_PROCESS_CTX_NEED (BIT(MPTCP_PUSH_PENDING) | \
3311 BIT(MPTCP_RETRANSMIT) | \
3312 BIT(MPTCP_FLUSH_JOIN_LIST))
3314 /* processes deferred events and flush wmem */
3315 static void mptcp_release_cb(struct sock *sk)
3316 __must_hold(&sk->sk_lock.slock)
3318 struct mptcp_sock *msk = mptcp_sk(sk);
3321 unsigned long flags = (msk->cb_flags & MPTCP_FLAGS_PROCESS_CTX_NEED) |
3326 /* the following actions acquire the subflow socket lock
3328 * 1) can't be invoked in atomic scope
3329 * 2) must avoid ABBA deadlock with msk socket spinlock: the RX
3330 * datapath acquires the msk socket spinlock while helding
3331 * the subflow socket lock
3333 msk->push_pending = 0;
3334 msk->cb_flags &= ~flags;
3335 spin_unlock_bh(&sk->sk_lock.slock);
3336 if (flags & BIT(MPTCP_FLUSH_JOIN_LIST))
3337 __mptcp_flush_join_list(sk);
3338 if (flags & BIT(MPTCP_PUSH_PENDING))
3339 __mptcp_push_pending(sk, 0);
3340 if (flags & BIT(MPTCP_RETRANSMIT))
3341 __mptcp_retrans(sk);
3344 spin_lock_bh(&sk->sk_lock.slock);
3347 if (__test_and_clear_bit(MPTCP_CLEAN_UNA, &msk->cb_flags))
3348 __mptcp_clean_una_wakeup(sk);
3349 if (unlikely(&msk->cb_flags)) {
3350 /* be sure to set the current sk state before tacking actions
3351 * depending on sk_state, that is processing MPTCP_ERROR_REPORT
3353 if (__test_and_clear_bit(MPTCP_CONNECTED, &msk->cb_flags))
3354 __mptcp_set_connected(sk);
3355 if (__test_and_clear_bit(MPTCP_ERROR_REPORT, &msk->cb_flags))
3356 __mptcp_error_report(sk);
3357 if (__test_and_clear_bit(MPTCP_RESET_SCHEDULER, &msk->cb_flags))
3358 msk->last_snd = NULL;
3361 __mptcp_update_rmem(sk);
3364 /* MP_JOIN client subflow must wait for 4th ack before sending any data:
3365 * TCP can't schedule delack timer before the subflow is fully established.
3366 * MPTCP uses the delack timer to do 3rd ack retransmissions
3368 static void schedule_3rdack_retransmission(struct sock *ssk)
3370 struct inet_connection_sock *icsk = inet_csk(ssk);
3371 struct tcp_sock *tp = tcp_sk(ssk);
3372 unsigned long timeout;
3374 if (mptcp_subflow_ctx(ssk)->fully_established)
3377 /* reschedule with a timeout above RTT, as we must look only for drop */
3379 timeout = usecs_to_jiffies(tp->srtt_us >> (3 - 1));
3381 timeout = TCP_TIMEOUT_INIT;
3384 WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER);
3385 icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
3386 icsk->icsk_ack.timeout = timeout;
3387 sk_reset_timer(ssk, &icsk->icsk_delack_timer, timeout);
3390 void mptcp_subflow_process_delegated(struct sock *ssk)
3392 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
3393 struct sock *sk = subflow->conn;
3395 if (test_bit(MPTCP_DELEGATE_SEND, &subflow->delegated_status)) {
3396 mptcp_data_lock(sk);
3397 if (!sock_owned_by_user(sk))
3398 __mptcp_subflow_push_pending(sk, ssk);
3400 __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags);
3401 mptcp_data_unlock(sk);
3402 mptcp_subflow_delegated_done(subflow, MPTCP_DELEGATE_SEND);
3404 if (test_bit(MPTCP_DELEGATE_ACK, &subflow->delegated_status)) {
3405 schedule_3rdack_retransmission(ssk);
3406 mptcp_subflow_delegated_done(subflow, MPTCP_DELEGATE_ACK);
3410 static int mptcp_hash(struct sock *sk)
3412 /* should never be called,
3413 * we hash the TCP subflows not the master socket
3419 static void mptcp_unhash(struct sock *sk)
3421 /* called from sk_common_release(), but nothing to do here */
3424 static int mptcp_get_port(struct sock *sk, unsigned short snum)
3426 struct mptcp_sock *msk = mptcp_sk(sk);
3427 struct socket *ssock;
3429 ssock = msk->subflow;
3430 pr_debug("msk=%p, subflow=%p", msk, ssock);
3431 if (WARN_ON_ONCE(!ssock))
3434 return inet_csk_get_port(ssock->sk, snum);
3437 void mptcp_finish_connect(struct sock *ssk)
3439 struct mptcp_subflow_context *subflow;
3440 struct mptcp_sock *msk;
3444 subflow = mptcp_subflow_ctx(ssk);
3448 pr_debug("msk=%p, token=%u", sk, subflow->token);
3450 mptcp_crypto_key_sha(subflow->remote_key, NULL, &ack_seq);
3452 subflow->map_seq = ack_seq;
3453 subflow->map_subflow_seq = 1;
3455 /* the socket is not connected yet, no msk/subflow ops can access/race
3456 * accessing the field below
3458 WRITE_ONCE(msk->remote_key, subflow->remote_key);
3459 WRITE_ONCE(msk->local_key, subflow->local_key);
3460 WRITE_ONCE(msk->write_seq, subflow->idsn + 1);
3461 WRITE_ONCE(msk->snd_nxt, msk->write_seq);
3462 WRITE_ONCE(msk->ack_seq, ack_seq);
3463 WRITE_ONCE(msk->can_ack, 1);
3464 WRITE_ONCE(msk->snd_una, msk->write_seq);
3465 atomic64_set(&msk->rcv_wnd_sent, ack_seq);
3467 mptcp_pm_new_connection(msk, ssk, 0);
3469 mptcp_rcv_space_init(msk, ssk);
3472 void mptcp_sock_graft(struct sock *sk, struct socket *parent)
3474 write_lock_bh(&sk->sk_callback_lock);
3475 rcu_assign_pointer(sk->sk_wq, &parent->wq);
3476 sk_set_socket(sk, parent);
3477 sk->sk_uid = SOCK_INODE(parent)->i_uid;
3478 write_unlock_bh(&sk->sk_callback_lock);
3481 bool mptcp_finish_join(struct sock *ssk)
3483 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
3484 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
3485 struct sock *parent = (void *)msk;
3488 pr_debug("msk=%p, subflow=%p", msk, subflow);
3490 /* mptcp socket already closing? */
3491 if (!mptcp_is_fully_established(parent)) {
3492 subflow->reset_reason = MPTCP_RST_EMPTCP;
3496 /* active subflow, already present inside the conn_list */
3497 if (!list_empty(&subflow->node)) {
3498 mptcp_subflow_joined(msk, ssk);
3502 if (!mptcp_pm_allow_new_subflow(msk))
3503 goto err_prohibited;
3505 /* If we can't acquire msk socket lock here, let the release callback
3508 mptcp_data_lock(parent);
3509 if (!sock_owned_by_user(parent)) {
3510 ret = __mptcp_finish_join(msk, ssk);
3513 list_add_tail(&subflow->node, &msk->conn_list);
3517 list_add_tail(&subflow->node, &msk->join_list);
3518 __set_bit(MPTCP_FLUSH_JOIN_LIST, &msk->cb_flags);
3520 mptcp_data_unlock(parent);
3524 subflow->reset_reason = MPTCP_RST_EPROHIBIT;
3531 static void mptcp_shutdown(struct sock *sk, int how)
3533 pr_debug("sk=%p, how=%d", sk, how);
3535 if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk))
3536 __mptcp_wr_shutdown(sk);
3539 static int mptcp_forward_alloc_get(const struct sock *sk)
3541 return sk->sk_forward_alloc + mptcp_sk(sk)->rmem_fwd_alloc;
3544 static int mptcp_ioctl_outq(const struct mptcp_sock *msk, u64 v)
3546 const struct sock *sk = (void *)msk;
3549 if (sk->sk_state == TCP_LISTEN)
3552 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
3555 delta = msk->write_seq - v;
3556 if (__mptcp_check_fallback(msk) && msk->first) {
3557 struct tcp_sock *tp = tcp_sk(msk->first);
3559 /* the first subflow is disconnected after close - see
3560 * __mptcp_close_ssk(). tcp_disconnect() moves the write_seq
3561 * so ignore that status, too.
3563 if (!((1 << msk->first->sk_state) &
3564 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE)))
3565 delta += READ_ONCE(tp->write_seq) - tp->snd_una;
3567 if (delta > INT_MAX)
3573 static int mptcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
3575 struct mptcp_sock *msk = mptcp_sk(sk);
3581 if (sk->sk_state == TCP_LISTEN)
3585 __mptcp_move_skbs(msk);
3586 answ = mptcp_inq_hint(sk);
3590 slow = lock_sock_fast(sk);
3591 answ = mptcp_ioctl_outq(msk, READ_ONCE(msk->snd_una));
3592 unlock_sock_fast(sk, slow);
3595 slow = lock_sock_fast(sk);
3596 answ = mptcp_ioctl_outq(msk, msk->snd_nxt);
3597 unlock_sock_fast(sk, slow);
3600 return -ENOIOCTLCMD;
3603 return put_user(answ, (int __user *)arg);
3606 static void mptcp_subflow_early_fallback(struct mptcp_sock *msk,
3607 struct mptcp_subflow_context *subflow)
3609 subflow->request_mptcp = 0;
3610 __mptcp_do_fallback(msk);
3613 static int mptcp_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
3615 struct mptcp_subflow_context *subflow;
3616 struct mptcp_sock *msk = mptcp_sk(sk);
3617 struct socket *ssock;
3620 ssock = __mptcp_nmpc_socket(msk);
3624 mptcp_token_destroy(msk);
3625 inet_sk_state_store(sk, TCP_SYN_SENT);
3626 subflow = mptcp_subflow_ctx(ssock->sk);
3627 #ifdef CONFIG_TCP_MD5SIG
3628 /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
3631 if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info))
3632 mptcp_subflow_early_fallback(msk, subflow);
3634 if (subflow->request_mptcp && mptcp_token_new_connect(ssock->sk)) {
3635 MPTCP_INC_STATS(sock_net(ssock->sk), MPTCP_MIB_TOKENFALLBACKINIT);
3636 mptcp_subflow_early_fallback(msk, subflow);
3638 if (likely(!__mptcp_check_fallback(msk)))
3639 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVE);
3641 /* if reaching here via the fastopen/sendmsg path, the caller already
3642 * acquired the subflow socket lock, too.
3644 if (msk->fastopening)
3645 err = __inet_stream_connect(ssock, uaddr, addr_len, O_NONBLOCK, 1);
3647 err = inet_stream_connect(ssock, uaddr, addr_len, O_NONBLOCK);
3648 inet_sk(sk)->defer_connect = inet_sk(ssock->sk)->defer_connect;
3650 /* on successful connect, the msk state will be moved to established by
3651 * subflow_finish_connect()
3653 if (unlikely(err && err != -EINPROGRESS)) {
3654 inet_sk_state_store(sk, inet_sk_state_load(ssock->sk));
3658 mptcp_copy_inaddrs(sk, ssock->sk);
3660 /* silence EINPROGRESS and let the caller inet_stream_connect
3661 * handle the connection in progress
3666 static struct proto mptcp_prot = {
3668 .owner = THIS_MODULE,
3669 .init = mptcp_init_sock,
3670 .connect = mptcp_connect,
3671 .disconnect = mptcp_disconnect,
3672 .close = mptcp_close,
3673 .accept = mptcp_accept,
3674 .setsockopt = mptcp_setsockopt,
3675 .getsockopt = mptcp_getsockopt,
3676 .shutdown = mptcp_shutdown,
3677 .destroy = mptcp_destroy,
3678 .sendmsg = mptcp_sendmsg,
3679 .ioctl = mptcp_ioctl,
3680 .recvmsg = mptcp_recvmsg,
3681 .release_cb = mptcp_release_cb,
3683 .unhash = mptcp_unhash,
3684 .get_port = mptcp_get_port,
3685 .forward_alloc_get = mptcp_forward_alloc_get,
3686 .sockets_allocated = &mptcp_sockets_allocated,
3688 .memory_allocated = &tcp_memory_allocated,
3689 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc,
3691 .memory_pressure = &tcp_memory_pressure,
3692 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
3693 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
3694 .sysctl_mem = sysctl_tcp_mem,
3695 .obj_size = sizeof(struct mptcp_sock),
3696 .slab_flags = SLAB_TYPESAFE_BY_RCU,
3697 .no_autobind = true,
3700 static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
3702 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3703 struct socket *ssock;
3706 lock_sock(sock->sk);
3707 ssock = __mptcp_nmpc_socket(msk);
3713 err = ssock->ops->bind(ssock, uaddr, addr_len);
3715 mptcp_copy_inaddrs(sock->sk, ssock->sk);
3718 release_sock(sock->sk);
3722 static int mptcp_listen(struct socket *sock, int backlog)
3724 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3725 struct socket *ssock;
3728 pr_debug("msk=%p", msk);
3730 lock_sock(sock->sk);
3731 ssock = __mptcp_nmpc_socket(msk);
3737 mptcp_token_destroy(msk);
3738 inet_sk_state_store(sock->sk, TCP_LISTEN);
3739 sock_set_flag(sock->sk, SOCK_RCU_FREE);
3741 err = ssock->ops->listen(ssock, backlog);
3742 inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
3744 mptcp_copy_inaddrs(sock->sk, ssock->sk);
3747 release_sock(sock->sk);
3751 static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
3752 int flags, bool kern)
3754 struct mptcp_sock *msk = mptcp_sk(sock->sk);
3755 struct socket *ssock;
3758 pr_debug("msk=%p", msk);
3760 /* Buggy applications can call accept on socket states other then LISTEN
3761 * but no need to allocate the first subflow just to error out.
3763 ssock = READ_ONCE(msk->subflow);
3767 err = ssock->ops->accept(sock, newsock, flags, kern);
3768 if (err == 0 && !mptcp_is_tcpsk(newsock->sk)) {
3769 struct mptcp_sock *msk = mptcp_sk(newsock->sk);
3770 struct mptcp_subflow_context *subflow;
3771 struct sock *newsk = newsock->sk;
3773 msk->in_accept_queue = 0;
3777 /* set ssk->sk_socket of accept()ed flows to mptcp socket.
3778 * This is needed so NOSPACE flag can be set from tcp stack.
3780 mptcp_for_each_subflow(msk, subflow) {
3781 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3783 if (!ssk->sk_socket)
3784 mptcp_sock_graft(ssk, newsock);
3787 /* Do late cleanup for the first subflow as necessary. Also
3788 * deal with bad peers not doing a complete shutdown.
3791 unlikely(inet_sk_state_load(msk->first) == TCP_CLOSE)) {
3792 __mptcp_close_ssk(newsk, msk->first,
3793 mptcp_subflow_ctx(msk->first), 0);
3794 if (unlikely(list_empty(&msk->conn_list)))
3795 inet_sk_state_store(newsk, TCP_CLOSE);
3798 release_sock(newsk);
3804 static __poll_t mptcp_check_writeable(struct mptcp_sock *msk)
3806 struct sock *sk = (struct sock *)msk;
3808 if (sk_stream_is_writeable(sk))
3809 return EPOLLOUT | EPOLLWRNORM;
3811 mptcp_set_nospace(sk);
3812 smp_mb__after_atomic(); /* msk->flags is changed by write_space cb */
3813 if (sk_stream_is_writeable(sk))
3814 return EPOLLOUT | EPOLLWRNORM;
3819 static __poll_t mptcp_poll(struct file *file, struct socket *sock,
3820 struct poll_table_struct *wait)
3822 struct sock *sk = sock->sk;
3823 struct mptcp_sock *msk;
3829 sock_poll_wait(file, sock, wait);
3831 state = inet_sk_state_load(sk);
3832 pr_debug("msk=%p state=%d flags=%lx", msk, state, msk->flags);
3833 if (state == TCP_LISTEN) {
3834 struct socket *ssock = READ_ONCE(msk->subflow);
3836 if (WARN_ON_ONCE(!ssock || !ssock->sk))
3839 return inet_csk_listen_poll(ssock->sk);
3842 shutdown = READ_ONCE(sk->sk_shutdown);
3843 if (shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
3845 if (shutdown & RCV_SHUTDOWN)
3846 mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
3848 if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) {
3849 mask |= mptcp_check_readable(msk);
3850 if (shutdown & SEND_SHUTDOWN)
3851 mask |= EPOLLOUT | EPOLLWRNORM;
3853 mask |= mptcp_check_writeable(msk);
3854 } else if (state == TCP_SYN_SENT && inet_sk(sk)->defer_connect) {
3855 /* cf tcp_poll() note about TFO */
3856 mask |= EPOLLOUT | EPOLLWRNORM;
3859 /* This barrier is coupled with smp_wmb() in __mptcp_error_report() */
3867 static const struct proto_ops mptcp_stream_ops = {
3869 .owner = THIS_MODULE,
3870 .release = inet_release,
3872 .connect = inet_stream_connect,
3873 .socketpair = sock_no_socketpair,
3874 .accept = mptcp_stream_accept,
3875 .getname = inet_getname,
3877 .ioctl = inet_ioctl,
3878 .gettstamp = sock_gettstamp,
3879 .listen = mptcp_listen,
3880 .shutdown = inet_shutdown,
3881 .setsockopt = sock_common_setsockopt,
3882 .getsockopt = sock_common_getsockopt,
3883 .sendmsg = inet_sendmsg,
3884 .recvmsg = inet_recvmsg,
3885 .mmap = sock_no_mmap,
3886 .sendpage = inet_sendpage,
3889 static struct inet_protosw mptcp_protosw = {
3890 .type = SOCK_STREAM,
3891 .protocol = IPPROTO_MPTCP,
3892 .prot = &mptcp_prot,
3893 .ops = &mptcp_stream_ops,
3894 .flags = INET_PROTOSW_ICSK,
3897 static int mptcp_napi_poll(struct napi_struct *napi, int budget)
3899 struct mptcp_delegated_action *delegated;
3900 struct mptcp_subflow_context *subflow;
3903 delegated = container_of(napi, struct mptcp_delegated_action, napi);
3904 while ((subflow = mptcp_subflow_delegated_next(delegated)) != NULL) {
3905 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
3907 bh_lock_sock_nested(ssk);
3908 if (!sock_owned_by_user(ssk) &&
3909 mptcp_subflow_has_delegated_action(subflow))
3910 mptcp_subflow_process_delegated(ssk);
3911 /* ... elsewhere tcp_release_cb_override already processed
3912 * the action or will do at next release_sock().
3913 * In both case must dequeue the subflow here - on the same
3914 * CPU that scheduled it.
3916 bh_unlock_sock(ssk);
3919 if (++work_done == budget)
3923 /* always provide a 0 'work_done' argument, so that napi_complete_done
3924 * will not try accessing the NULL napi->dev ptr
3926 napi_complete_done(napi, 0);
3930 void __init mptcp_proto_init(void)
3932 struct mptcp_delegated_action *delegated;
3935 mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo;
3937 if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL))
3938 panic("Failed to allocate MPTCP pcpu counter\n");
3940 init_dummy_netdev(&mptcp_napi_dev);
3941 for_each_possible_cpu(cpu) {
3942 delegated = per_cpu_ptr(&mptcp_delegated_actions, cpu);
3943 INIT_LIST_HEAD(&delegated->head);
3944 netif_napi_add_tx(&mptcp_napi_dev, &delegated->napi,
3946 napi_enable(&delegated->napi);
3949 mptcp_subflow_init();
3953 if (proto_register(&mptcp_prot, 1) != 0)
3954 panic("Failed to register MPTCP proto.\n");
3956 inet_register_protosw(&mptcp_protosw);
3958 BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb));
3961 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
3962 static const struct proto_ops mptcp_v6_stream_ops = {
3964 .owner = THIS_MODULE,
3965 .release = inet6_release,
3967 .connect = inet_stream_connect,
3968 .socketpair = sock_no_socketpair,
3969 .accept = mptcp_stream_accept,
3970 .getname = inet6_getname,
3972 .ioctl = inet6_ioctl,
3973 .gettstamp = sock_gettstamp,
3974 .listen = mptcp_listen,
3975 .shutdown = inet_shutdown,
3976 .setsockopt = sock_common_setsockopt,
3977 .getsockopt = sock_common_getsockopt,
3978 .sendmsg = inet6_sendmsg,
3979 .recvmsg = inet6_recvmsg,
3980 .mmap = sock_no_mmap,
3981 .sendpage = inet_sendpage,
3982 #ifdef CONFIG_COMPAT
3983 .compat_ioctl = inet6_compat_ioctl,
3987 static struct proto mptcp_v6_prot;
3989 static struct inet_protosw mptcp_v6_protosw = {
3990 .type = SOCK_STREAM,
3991 .protocol = IPPROTO_MPTCP,
3992 .prot = &mptcp_v6_prot,
3993 .ops = &mptcp_v6_stream_ops,
3994 .flags = INET_PROTOSW_ICSK,
3997 int __init mptcp_proto_v6_init(void)
4001 mptcp_v6_prot = mptcp_prot;
4002 strcpy(mptcp_v6_prot.name, "MPTCPv6");
4003 mptcp_v6_prot.slab = NULL;
4004 mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock);
4006 err = proto_register(&mptcp_v6_prot, 1);
4010 err = inet6_register_protosw(&mptcp_v6_protosw);
4012 proto_unregister(&mptcp_v6_prot);