Update Linux to v5.10.109
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.109.tar.xz
Change-Id: I19bca9fc6762d4e63bcf3e4cba88bbe560d9c76c
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
new file mode 100644
index 0000000..8123c79
--- /dev/null
+++ b/net/mptcp/protocol.c
@@ -0,0 +1,2900 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Multipath TCP
+ *
+ * Copyright (c) 2017 - 2019, Intel Corporation.
+ */
+
+#define pr_fmt(fmt) "MPTCP: " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/sched/signal.h>
+#include <linux/atomic.h>
+#include <net/sock.h>
+#include <net/inet_common.h>
+#include <net/inet_hashtables.h>
+#include <net/protocol.h>
+#include <net/tcp.h>
+#include <net/tcp_states.h>
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+#include <net/transp_v6.h>
+#endif
+#include <net/mptcp.h>
+#include "protocol.h"
+#include "mib.h"
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+struct mptcp6_sock {
+ struct mptcp_sock msk;
+ struct ipv6_pinfo np;
+};
+#endif
+
+struct mptcp_skb_cb {
+ u64 map_seq;
+ u64 end_seq;
+ u32 offset;
+};
+
+#define MPTCP_SKB_CB(__skb) ((struct mptcp_skb_cb *)&((__skb)->cb[0]))
+
+static struct percpu_counter mptcp_sockets_allocated;
+
+/* If msk has an initial subflow socket, and the MP_CAPABLE handshake has not
+ * completed yet or has failed, return the subflow socket.
+ * Otherwise return NULL.
+ */
+static struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk)
+{
+ if (!msk->subflow || READ_ONCE(msk->can_ack))
+ return NULL;
+
+ return msk->subflow;
+}
+
+static bool mptcp_is_tcpsk(struct sock *sk)
+{
+ struct socket *sock = sk->sk_socket;
+
+ if (unlikely(sk->sk_prot == &tcp_prot)) {
+ /* we are being invoked after mptcp_accept() has
+ * accepted a non-mp-capable flow: sk is a tcp_sk,
+ * not an mptcp one.
+ *
+ * Hand the socket over to tcp so all further socket ops
+ * bypass mptcp.
+ */
+ sock->ops = &inet_stream_ops;
+ return true;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ } else if (unlikely(sk->sk_prot == &tcpv6_prot)) {
+ sock->ops = &inet6_stream_ops;
+ return true;
+#endif
+ }
+
+ return false;
+}
+
+static struct sock *__mptcp_tcp_fallback(struct mptcp_sock *msk)
+{
+ sock_owned_by_me((const struct sock *)msk);
+
+ if (likely(!__mptcp_check_fallback(msk)))
+ return NULL;
+
+ return msk->first;
+}
+
+static int __mptcp_socket_create(struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow;
+ struct sock *sk = (struct sock *)msk;
+ struct socket *ssock;
+ int err;
+
+ err = mptcp_subflow_create_socket(sk, &ssock);
+ if (err)
+ return err;
+
+ msk->first = ssock->sk;
+ msk->subflow = ssock;
+ subflow = mptcp_subflow_ctx(ssock->sk);
+ list_add(&subflow->node, &msk->conn_list);
+ subflow->request_mptcp = 1;
+
+ /* accept() will wait on first subflow sk_wq, and we always wakes up
+ * via msk->sk_socket
+ */
+ RCU_INIT_POINTER(msk->first->sk_wq, &sk->sk_socket->wq);
+
+ return 0;
+}
+
+static void mptcp_drop(struct sock *sk, struct sk_buff *skb)
+{
+ sk_drops_add(sk, skb);
+ __kfree_skb(skb);
+}
+
+static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to,
+ struct sk_buff *from)
+{
+ bool fragstolen;
+ int delta;
+
+ if (MPTCP_SKB_CB(from)->offset ||
+ !skb_try_coalesce(to, from, &fragstolen, &delta))
+ return false;
+
+ pr_debug("colesced seq %llx into %llx new len %d new end seq %llx",
+ MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq,
+ to->len, MPTCP_SKB_CB(from)->end_seq);
+ MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq;
+ kfree_skb_partial(from, fragstolen);
+ atomic_add(delta, &sk->sk_rmem_alloc);
+ sk_mem_charge(sk, delta);
+ return true;
+}
+
+static bool mptcp_ooo_try_coalesce(struct mptcp_sock *msk, struct sk_buff *to,
+ struct sk_buff *from)
+{
+ if (MPTCP_SKB_CB(from)->map_seq != MPTCP_SKB_CB(to)->end_seq)
+ return false;
+
+ return mptcp_try_coalesce((struct sock *)msk, to, from);
+}
+
+/* "inspired" by tcp_data_queue_ofo(), main differences:
+ * - use mptcp seqs
+ * - don't cope with sacks
+ */
+static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb)
+{
+ struct sock *sk = (struct sock *)msk;
+ struct rb_node **p, *parent;
+ u64 seq, end_seq, max_seq;
+ struct sk_buff *skb1;
+ int space;
+
+ seq = MPTCP_SKB_CB(skb)->map_seq;
+ end_seq = MPTCP_SKB_CB(skb)->end_seq;
+ space = tcp_space(sk);
+ max_seq = space > 0 ? space + msk->ack_seq : msk->ack_seq;
+
+ pr_debug("msk=%p seq=%llx limit=%llx empty=%d", msk, seq, max_seq,
+ RB_EMPTY_ROOT(&msk->out_of_order_queue));
+ if (after64(seq, max_seq)) {
+ /* out of window */
+ mptcp_drop(sk, skb);
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_NODSSWINDOW);
+ return;
+ }
+
+ p = &msk->out_of_order_queue.rb_node;
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUE);
+ if (RB_EMPTY_ROOT(&msk->out_of_order_queue)) {
+ rb_link_node(&skb->rbnode, NULL, p);
+ rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
+ msk->ooo_last_skb = skb;
+ goto end;
+ }
+
+ /* with 2 subflows, adding at end of ooo queue is quite likely
+ * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup.
+ */
+ if (mptcp_ooo_try_coalesce(msk, msk->ooo_last_skb, skb)) {
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
+ return;
+ }
+
+ /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */
+ if (!before64(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) {
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
+ parent = &msk->ooo_last_skb->rbnode;
+ p = &parent->rb_right;
+ goto insert;
+ }
+
+ /* Find place to insert this segment. Handle overlaps on the way. */
+ parent = NULL;
+ while (*p) {
+ parent = *p;
+ skb1 = rb_to_skb(parent);
+ if (before64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
+ p = &parent->rb_left;
+ continue;
+ }
+ if (before64(seq, MPTCP_SKB_CB(skb1)->end_seq)) {
+ if (!after64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) {
+ /* All the bits are present. Drop. */
+ mptcp_drop(sk, skb);
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
+ return;
+ }
+ if (after64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
+ /* partial overlap:
+ * | skb |
+ * | skb1 |
+ * continue traversing
+ */
+ } else {
+ /* skb's seq == skb1's seq and skb covers skb1.
+ * Replace skb1 with skb.
+ */
+ rb_replace_node(&skb1->rbnode, &skb->rbnode,
+ &msk->out_of_order_queue);
+ mptcp_drop(sk, skb1);
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
+ goto merge_right;
+ }
+ } else if (mptcp_ooo_try_coalesce(msk, skb1, skb)) {
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
+ return;
+ }
+ p = &parent->rb_right;
+ }
+
+insert:
+ /* Insert segment into RB tree. */
+ rb_link_node(&skb->rbnode, parent, p);
+ rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
+
+merge_right:
+ /* Remove other segments covered by skb. */
+ while ((skb1 = skb_rb_next(skb)) != NULL) {
+ if (before64(end_seq, MPTCP_SKB_CB(skb1)->end_seq))
+ break;
+ rb_erase(&skb1->rbnode, &msk->out_of_order_queue);
+ mptcp_drop(sk, skb1);
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
+ }
+ /* If there is no skb after us, we are the last_skb ! */
+ if (!skb1)
+ msk->ooo_last_skb = skb;
+
+end:
+ skb_condense(skb);
+ skb_set_owner_r(skb, sk);
+}
+
+static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk,
+ struct sk_buff *skb, unsigned int offset,
+ size_t copy_len)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ struct sock *sk = (struct sock *)msk;
+ struct sk_buff *tail;
+
+ __skb_unlink(skb, &ssk->sk_receive_queue);
+
+ skb_ext_reset(skb);
+ skb_orphan(skb);
+
+ /* try to fetch required memory from subflow */
+ if (!sk_rmem_schedule(sk, skb, skb->truesize)) {
+ int amount = sk_mem_pages(skb->truesize) << SK_MEM_QUANTUM_SHIFT;
+
+ if (ssk->sk_forward_alloc < amount)
+ goto drop;
+
+ ssk->sk_forward_alloc -= amount;
+ sk->sk_forward_alloc += amount;
+ }
+
+ /* the skb map_seq accounts for the skb offset:
+ * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq
+ * value
+ */
+ MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow);
+ MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len;
+ MPTCP_SKB_CB(skb)->offset = offset;
+
+ if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) {
+ /* in sequence */
+ WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len);
+ tail = skb_peek_tail(&sk->sk_receive_queue);
+ if (tail && mptcp_try_coalesce(sk, tail, skb))
+ return true;
+
+ skb_set_owner_r(skb, sk);
+ __skb_queue_tail(&sk->sk_receive_queue, skb);
+ return true;
+ } else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) {
+ mptcp_data_queue_ofo(msk, skb);
+ return false;
+ }
+
+ /* old data, keep it simple and drop the whole pkt, sender
+ * will retransmit as needed, if needed.
+ */
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
+drop:
+ mptcp_drop(sk, skb);
+ return false;
+}
+
+static void mptcp_stop_timer(struct sock *sk)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+
+ sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
+ mptcp_sk(sk)->timer_ival = 0;
+}
+
+static void mptcp_check_data_fin_ack(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ if (__mptcp_check_fallback(msk))
+ return;
+
+ /* Look for an acknowledged DATA_FIN */
+ if (((1 << sk->sk_state) &
+ (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) &&
+ msk->write_seq == atomic64_read(&msk->snd_una)) {
+ mptcp_stop_timer(sk);
+
+ WRITE_ONCE(msk->snd_data_fin_enable, 0);
+
+ switch (sk->sk_state) {
+ case TCP_FIN_WAIT1:
+ inet_sk_state_store(sk, TCP_FIN_WAIT2);
+ sk->sk_state_change(sk);
+ break;
+ case TCP_CLOSING:
+ case TCP_LAST_ACK:
+ inet_sk_state_store(sk, TCP_CLOSE);
+ sk->sk_state_change(sk);
+ break;
+ }
+
+ if (sk->sk_shutdown == SHUTDOWN_MASK ||
+ sk->sk_state == TCP_CLOSE)
+ sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
+ else
+ sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
+ }
+}
+
+static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ if (READ_ONCE(msk->rcv_data_fin) &&
+ ((1 << sk->sk_state) &
+ (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) {
+ u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq);
+
+ if (msk->ack_seq == rcv_data_fin_seq) {
+ if (seq)
+ *seq = rcv_data_fin_seq;
+
+ return true;
+ }
+ }
+
+ return false;
+}
+
+static void mptcp_set_timeout(const struct sock *sk, const struct sock *ssk)
+{
+ long tout = ssk && inet_csk(ssk)->icsk_pending ?
+ inet_csk(ssk)->icsk_timeout - jiffies : 0;
+
+ if (tout <= 0)
+ tout = mptcp_sk(sk)->timer_ival;
+ mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
+}
+
+static void mptcp_check_data_fin(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ u64 rcv_data_fin_seq;
+
+ if (__mptcp_check_fallback(msk) || !msk->first)
+ return;
+
+ /* Need to ack a DATA_FIN received from a peer while this side
+ * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2.
+ * msk->rcv_data_fin was set when parsing the incoming options
+ * at the subflow level and the msk lock was not held, so this
+ * is the first opportunity to act on the DATA_FIN and change
+ * the msk state.
+ *
+ * If we are caught up to the sequence number of the incoming
+ * DATA_FIN, send the DATA_ACK now and do state transition. If
+ * not caught up, do nothing and let the recv code send DATA_ACK
+ * when catching up.
+ */
+
+ if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) {
+ struct mptcp_subflow_context *subflow;
+
+ WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1);
+ WRITE_ONCE(msk->rcv_data_fin, 0);
+
+ sk->sk_shutdown |= RCV_SHUTDOWN;
+ smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
+ set_bit(MPTCP_DATA_READY, &msk->flags);
+
+ switch (sk->sk_state) {
+ case TCP_ESTABLISHED:
+ inet_sk_state_store(sk, TCP_CLOSE_WAIT);
+ break;
+ case TCP_FIN_WAIT1:
+ inet_sk_state_store(sk, TCP_CLOSING);
+ break;
+ case TCP_FIN_WAIT2:
+ inet_sk_state_store(sk, TCP_CLOSE);
+ // @@ Close subflows now?
+ break;
+ default:
+ /* Other states not expected */
+ WARN_ON_ONCE(1);
+ break;
+ }
+
+ mptcp_set_timeout(sk, NULL);
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ lock_sock(ssk);
+ tcp_send_ack(ssk);
+ release_sock(ssk);
+ }
+
+ sk->sk_state_change(sk);
+
+ if (sk->sk_shutdown == SHUTDOWN_MASK ||
+ sk->sk_state == TCP_CLOSE)
+ sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
+ else
+ sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
+ }
+}
+
+static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
+ struct sock *ssk,
+ unsigned int *bytes)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ struct sock *sk = (struct sock *)msk;
+ unsigned int moved = 0;
+ bool more_data_avail;
+ struct tcp_sock *tp;
+ u32 old_copied_seq;
+ bool done = false;
+
+ pr_debug("msk=%p ssk=%p", msk, ssk);
+ tp = tcp_sk(ssk);
+ old_copied_seq = tp->copied_seq;
+ do {
+ u32 map_remaining, offset;
+ u32 seq = tp->copied_seq;
+ struct sk_buff *skb;
+ bool fin;
+
+ /* try to move as much data as available */
+ map_remaining = subflow->map_data_len -
+ mptcp_subflow_get_map_offset(subflow);
+
+ skb = skb_peek(&ssk->sk_receive_queue);
+ if (!skb) {
+ /* if no data is found, a racing workqueue/recvmsg
+ * already processed the new data, stop here or we
+ * can enter an infinite loop
+ */
+ if (!moved)
+ done = true;
+ break;
+ }
+
+ if (__mptcp_check_fallback(msk)) {
+ /* if we are running under the workqueue, TCP could have
+ * collapsed skbs between dummy map creation and now
+ * be sure to adjust the size
+ */
+ map_remaining = skb->len;
+ subflow->map_data_len = skb->len;
+ }
+
+ offset = seq - TCP_SKB_CB(skb)->seq;
+ fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
+ if (fin) {
+ done = true;
+ seq++;
+ }
+
+ if (offset < skb->len) {
+ size_t len = skb->len - offset;
+
+ if (tp->urg_data)
+ done = true;
+
+ if (__mptcp_move_skb(msk, ssk, skb, offset, len))
+ moved += len;
+ seq += len;
+
+ if (WARN_ON_ONCE(map_remaining < len))
+ break;
+ } else {
+ WARN_ON_ONCE(!fin);
+ sk_eat_skb(ssk, skb);
+ done = true;
+ }
+
+ WRITE_ONCE(tp->copied_seq, seq);
+ more_data_avail = mptcp_subflow_data_available(ssk);
+
+ if (atomic_read(&sk->sk_rmem_alloc) > READ_ONCE(sk->sk_rcvbuf)) {
+ done = true;
+ break;
+ }
+ } while (more_data_avail);
+
+ *bytes += moved;
+ if (tp->copied_seq != old_copied_seq)
+ tcp_cleanup_rbuf(ssk, 1);
+
+ return done;
+}
+
+static bool mptcp_ofo_queue(struct mptcp_sock *msk)
+{
+ struct sock *sk = (struct sock *)msk;
+ struct sk_buff *skb, *tail;
+ bool moved = false;
+ struct rb_node *p;
+ u64 end_seq;
+
+ p = rb_first(&msk->out_of_order_queue);
+ pr_debug("msk=%p empty=%d", msk, RB_EMPTY_ROOT(&msk->out_of_order_queue));
+ while (p) {
+ skb = rb_to_skb(p);
+ if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq))
+ break;
+
+ p = rb_next(p);
+ rb_erase(&skb->rbnode, &msk->out_of_order_queue);
+
+ if (unlikely(!after64(MPTCP_SKB_CB(skb)->end_seq,
+ msk->ack_seq))) {
+ mptcp_drop(sk, skb);
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
+ continue;
+ }
+
+ end_seq = MPTCP_SKB_CB(skb)->end_seq;
+ tail = skb_peek_tail(&sk->sk_receive_queue);
+ if (!tail || !mptcp_ooo_try_coalesce(msk, tail, skb)) {
+ int delta = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq;
+
+ /* skip overlapping data, if any */
+ pr_debug("uncoalesced seq=%llx ack seq=%llx delta=%d",
+ MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq,
+ delta);
+ MPTCP_SKB_CB(skb)->offset += delta;
+ __skb_queue_tail(&sk->sk_receive_queue, skb);
+ }
+ msk->ack_seq = end_seq;
+ moved = true;
+ }
+ return moved;
+}
+
+/* In most cases we will be able to lock the mptcp socket. If its already
+ * owned, we need to defer to the work queue to avoid ABBA deadlock.
+ */
+static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk)
+{
+ struct sock *sk = (struct sock *)msk;
+ unsigned int moved = 0;
+
+ if (READ_ONCE(sk->sk_lock.owned))
+ return false;
+
+ if (unlikely(!spin_trylock_bh(&sk->sk_lock.slock)))
+ return false;
+
+ /* must re-check after taking the lock */
+ if (!READ_ONCE(sk->sk_lock.owned)) {
+ __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
+ mptcp_ofo_queue(msk);
+
+ /* If the moves have caught up with the DATA_FIN sequence number
+ * it's time to ack the DATA_FIN and change socket state, but
+ * this is not a good place to change state. Let the workqueue
+ * do it.
+ */
+ if (mptcp_pending_data_fin(sk, NULL) &&
+ schedule_work(&msk->work))
+ sock_hold(sk);
+ }
+
+ spin_unlock_bh(&sk->sk_lock.slock);
+
+ return moved > 0;
+}
+
+void mptcp_data_ready(struct sock *sk, struct sock *ssk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ bool wake;
+
+ /* move_skbs_to_msk below can legitly clear the data_avail flag,
+ * but we will need later to properly woke the reader, cache its
+ * value
+ */
+ wake = subflow->data_avail == MPTCP_SUBFLOW_DATA_AVAIL;
+ if (wake)
+ set_bit(MPTCP_DATA_READY, &msk->flags);
+
+ if (atomic_read(&sk->sk_rmem_alloc) < READ_ONCE(sk->sk_rcvbuf) &&
+ move_skbs_to_msk(msk, ssk))
+ goto wake;
+
+ /* don't schedule if mptcp sk is (still) over limit */
+ if (atomic_read(&sk->sk_rmem_alloc) > READ_ONCE(sk->sk_rcvbuf))
+ goto wake;
+
+ /* mptcp socket is owned, release_cb should retry */
+ if (!test_and_set_bit(TCP_DELACK_TIMER_DEFERRED,
+ &sk->sk_tsq_flags)) {
+ sock_hold(sk);
+
+ /* need to try again, its possible release_cb() has already
+ * been called after the test_and_set_bit() above.
+ */
+ move_skbs_to_msk(msk, ssk);
+ }
+wake:
+ if (wake)
+ sk->sk_data_ready(sk);
+}
+
+static void __mptcp_flush_join_list(struct mptcp_sock *msk)
+{
+ if (likely(list_empty(&msk->join_list)))
+ return;
+
+ spin_lock_bh(&msk->join_list_lock);
+ list_splice_tail_init(&msk->join_list, &msk->conn_list);
+ spin_unlock_bh(&msk->join_list_lock);
+}
+
+static bool mptcp_timer_pending(struct sock *sk)
+{
+ return timer_pending(&inet_csk(sk)->icsk_retransmit_timer);
+}
+
+static void mptcp_reset_timer(struct sock *sk)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ unsigned long tout;
+
+ /* should never be called with mptcp level timer cleared */
+ tout = READ_ONCE(mptcp_sk(sk)->timer_ival);
+ if (WARN_ON_ONCE(!tout))
+ tout = TCP_RTO_MIN;
+ sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout);
+}
+
+void mptcp_data_acked(struct sock *sk)
+{
+ mptcp_reset_timer(sk);
+
+ if ((!test_bit(MPTCP_SEND_SPACE, &mptcp_sk(sk)->flags) ||
+ (inet_sk_state_load(sk) != TCP_ESTABLISHED)) &&
+ schedule_work(&mptcp_sk(sk)->work))
+ sock_hold(sk);
+}
+
+void mptcp_subflow_eof(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ if (!test_and_set_bit(MPTCP_WORK_EOF, &msk->flags) &&
+ schedule_work(&msk->work))
+ sock_hold(sk);
+}
+
+static void mptcp_check_for_eof(struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow;
+ struct sock *sk = (struct sock *)msk;
+ int receivers = 0;
+
+ mptcp_for_each_subflow(msk, subflow)
+ receivers += !subflow->rx_eof;
+
+ if (!receivers && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
+ /* hopefully temporary hack: propagate shutdown status
+ * to msk, when all subflows agree on it
+ */
+ sk->sk_shutdown |= RCV_SHUTDOWN;
+
+ smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
+ set_bit(MPTCP_DATA_READY, &msk->flags);
+ sk->sk_data_ready(sk);
+ }
+}
+
+static bool mptcp_ext_cache_refill(struct mptcp_sock *msk)
+{
+ const struct sock *sk = (const struct sock *)msk;
+
+ if (!msk->cached_ext)
+ msk->cached_ext = __skb_ext_alloc(sk->sk_allocation);
+
+ return !!msk->cached_ext;
+}
+
+static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow;
+ struct sock *sk = (struct sock *)msk;
+
+ sock_owned_by_me(sk);
+
+ mptcp_for_each_subflow(msk, subflow) {
+ if (subflow->data_avail)
+ return mptcp_subflow_tcp_sock(subflow);
+ }
+
+ return NULL;
+}
+
+static bool mptcp_skb_can_collapse_to(u64 write_seq,
+ const struct sk_buff *skb,
+ const struct mptcp_ext *mpext)
+{
+ if (!tcp_skb_can_collapse_to(skb))
+ return false;
+
+ /* can collapse only if MPTCP level sequence is in order */
+ return mpext && mpext->data_seq + mpext->data_len == write_seq;
+}
+
+/* we can append data to the given data frag if:
+ * - there is space available in the backing page_frag
+ * - the data frag tail matches the current page_frag free offset
+ * - the data frag end sequence number matches the current write seq
+ */
+static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk,
+ const struct page_frag *pfrag,
+ const struct mptcp_data_frag *df)
+{
+ return df && pfrag->page == df->page &&
+ pfrag->offset == (df->offset + df->data_len) &&
+ df->data_seq + df->data_len == msk->write_seq;
+}
+
+static void dfrag_uncharge(struct sock *sk, int len)
+{
+ sk_mem_uncharge(sk, len);
+ sk_wmem_queued_add(sk, -len);
+}
+
+static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag)
+{
+ int len = dfrag->data_len + dfrag->overhead;
+
+ list_del(&dfrag->list);
+ dfrag_uncharge(sk, len);
+ put_page(dfrag->page);
+}
+
+static bool mptcp_is_writeable(struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow;
+
+ if (!sk_stream_is_writeable((struct sock *)msk))
+ return false;
+
+ mptcp_for_each_subflow(msk, subflow) {
+ if (sk_stream_is_writeable(subflow->tcp_sock))
+ return true;
+ }
+ return false;
+}
+
+static void mptcp_clean_una(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct mptcp_data_frag *dtmp, *dfrag;
+ bool cleaned = false;
+ u64 snd_una;
+
+ /* on fallback we just need to ignore snd_una, as this is really
+ * plain TCP
+ */
+ if (__mptcp_check_fallback(msk))
+ atomic64_set(&msk->snd_una, msk->write_seq);
+ snd_una = atomic64_read(&msk->snd_una);
+
+ list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) {
+ if (after64(dfrag->data_seq + dfrag->data_len, snd_una))
+ break;
+
+ dfrag_clear(sk, dfrag);
+ cleaned = true;
+ }
+
+ dfrag = mptcp_rtx_head(sk);
+ if (dfrag && after64(snd_una, dfrag->data_seq)) {
+ u64 delta = snd_una - dfrag->data_seq;
+
+ if (WARN_ON_ONCE(delta > dfrag->data_len))
+ goto out;
+
+ dfrag->data_seq += delta;
+ dfrag->offset += delta;
+ dfrag->data_len -= delta;
+
+ dfrag_uncharge(sk, delta);
+ cleaned = true;
+ }
+
+out:
+ if (cleaned) {
+ sk_mem_reclaim_partial(sk);
+
+ /* Only wake up writers if a subflow is ready */
+ if (mptcp_is_writeable(msk)) {
+ set_bit(MPTCP_SEND_SPACE, &mptcp_sk(sk)->flags);
+ smp_mb__after_atomic();
+
+ /* set SEND_SPACE before sk_stream_write_space clears
+ * NOSPACE
+ */
+ sk_stream_write_space(sk);
+ }
+ }
+}
+
+/* ensure we get enough memory for the frag hdr, beyond some minimal amount of
+ * data
+ */
+static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag)
+{
+ if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag),
+ pfrag, sk->sk_allocation)))
+ return true;
+
+ sk->sk_prot->enter_memory_pressure(sk);
+ sk_stream_moderate_sndbuf(sk);
+ return false;
+}
+
+static struct mptcp_data_frag *
+mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag,
+ int orig_offset)
+{
+ int offset = ALIGN(orig_offset, sizeof(long));
+ struct mptcp_data_frag *dfrag;
+
+ dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset);
+ dfrag->data_len = 0;
+ dfrag->data_seq = msk->write_seq;
+ dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag);
+ dfrag->offset = offset + sizeof(struct mptcp_data_frag);
+ dfrag->page = pfrag->page;
+
+ return dfrag;
+}
+
+static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
+ struct msghdr *msg, struct mptcp_data_frag *dfrag,
+ long *timeo, int *pmss_now,
+ int *ps_goal)
+{
+ int mss_now, avail_size, size_goal, offset, ret, frag_truesize = 0;
+ bool dfrag_collapsed, can_collapse = false;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct mptcp_ext *mpext = NULL;
+ bool retransmission = !!dfrag;
+ struct sk_buff *skb, *tail;
+ struct page_frag *pfrag;
+ struct page *page;
+ u64 *write_seq;
+ size_t psize;
+
+ /* use the mptcp page cache so that we can easily move the data
+ * from one substream to another, but do per subflow memory accounting
+ * Note: pfrag is used only !retransmission, but the compiler if
+ * fooled into a warning if we don't init here
+ */
+ pfrag = sk_page_frag(sk);
+ if (!retransmission) {
+ write_seq = &msk->write_seq;
+ page = pfrag->page;
+ } else {
+ write_seq = &dfrag->data_seq;
+ page = dfrag->page;
+ }
+
+ /* compute copy limit */
+ mss_now = tcp_send_mss(ssk, &size_goal, msg->msg_flags);
+ *pmss_now = mss_now;
+ *ps_goal = size_goal;
+ avail_size = size_goal;
+ skb = tcp_write_queue_tail(ssk);
+ if (skb) {
+ mpext = skb_ext_find(skb, SKB_EXT_MPTCP);
+
+ /* Limit the write to the size available in the
+ * current skb, if any, so that we create at most a new skb.
+ * Explicitly tells TCP internals to avoid collapsing on later
+ * queue management operation, to avoid breaking the ext <->
+ * SSN association set here
+ */
+ can_collapse = (size_goal - skb->len > 0) &&
+ mptcp_skb_can_collapse_to(*write_seq, skb, mpext);
+ if (!can_collapse)
+ TCP_SKB_CB(skb)->eor = 1;
+ else
+ avail_size = size_goal - skb->len;
+ }
+
+ if (!retransmission) {
+ /* reuse tail pfrag, if possible, or carve a new one from the
+ * page allocator
+ */
+ dfrag = mptcp_rtx_tail(sk);
+ offset = pfrag->offset;
+ dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag);
+ if (!dfrag_collapsed) {
+ dfrag = mptcp_carve_data_frag(msk, pfrag, offset);
+ offset = dfrag->offset;
+ frag_truesize = dfrag->overhead;
+ }
+ psize = min_t(size_t, pfrag->size - offset, avail_size);
+
+ /* Copy to page */
+ pr_debug("left=%zu", msg_data_left(msg));
+ psize = copy_page_from_iter(pfrag->page, offset,
+ min_t(size_t, msg_data_left(msg),
+ psize),
+ &msg->msg_iter);
+ pr_debug("left=%zu", msg_data_left(msg));
+ if (!psize)
+ return -EINVAL;
+
+ if (!sk_wmem_schedule(sk, psize + dfrag->overhead)) {
+ iov_iter_revert(&msg->msg_iter, psize);
+ return -ENOMEM;
+ }
+ } else {
+ offset = dfrag->offset;
+ psize = min_t(size_t, dfrag->data_len, avail_size);
+ }
+
+ /* tell the TCP stack to delay the push so that we can safely
+ * access the skb after the sendpages call
+ */
+ ret = do_tcp_sendpages(ssk, page, offset, psize,
+ msg->msg_flags | MSG_SENDPAGE_NOTLAST | MSG_DONTWAIT);
+ if (ret <= 0) {
+ if (!retransmission)
+ iov_iter_revert(&msg->msg_iter, psize);
+ return ret;
+ }
+
+ frag_truesize += ret;
+ if (!retransmission) {
+ if (unlikely(ret < psize))
+ iov_iter_revert(&msg->msg_iter, psize - ret);
+
+ /* send successful, keep track of sent data for mptcp-level
+ * retransmission
+ */
+ dfrag->data_len += ret;
+ if (!dfrag_collapsed) {
+ get_page(dfrag->page);
+ list_add_tail(&dfrag->list, &msk->rtx_queue);
+ sk_wmem_queued_add(sk, frag_truesize);
+ } else {
+ sk_wmem_queued_add(sk, ret);
+ }
+
+ /* charge data on mptcp rtx queue to the master socket
+ * Note: we charge such data both to sk and ssk
+ */
+ sk->sk_forward_alloc -= frag_truesize;
+ }
+
+ /* if the tail skb extension is still the cached one, collapsing
+ * really happened. Note: we can't check for 'same skb' as the sk_buff
+ * hdr on tail can be transmitted, freed and re-allocated by the
+ * do_tcp_sendpages() call
+ */
+ tail = tcp_write_queue_tail(ssk);
+ if (mpext && tail && mpext == skb_ext_find(tail, SKB_EXT_MPTCP)) {
+ WARN_ON_ONCE(!can_collapse);
+ mpext->data_len += ret;
+ goto out;
+ }
+
+ skb = tcp_write_queue_tail(ssk);
+ mpext = __skb_ext_set(skb, SKB_EXT_MPTCP, msk->cached_ext);
+ msk->cached_ext = NULL;
+
+ memset(mpext, 0, sizeof(*mpext));
+ mpext->data_seq = *write_seq;
+ mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq;
+ mpext->data_len = ret;
+ mpext->use_map = 1;
+ mpext->dsn64 = 1;
+
+ pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d",
+ mpext->data_seq, mpext->subflow_seq, mpext->data_len,
+ mpext->dsn64);
+
+out:
+ if (!retransmission)
+ pfrag->offset += frag_truesize;
+ WRITE_ONCE(*write_seq, *write_seq + ret);
+ mptcp_subflow_ctx(ssk)->rel_write_seq += ret;
+
+ return ret;
+}
+
+static void mptcp_nospace(struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow;
+
+ clear_bit(MPTCP_SEND_SPACE, &msk->flags);
+ smp_mb__after_atomic(); /* msk->flags is changed by write_space cb */
+
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+ struct socket *sock = READ_ONCE(ssk->sk_socket);
+
+ /* enables ssk->write_space() callbacks */
+ if (sock)
+ set_bit(SOCK_NOSPACE, &sock->flags);
+ }
+}
+
+static bool mptcp_subflow_active(struct mptcp_subflow_context *subflow)
+{
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ /* can't send if JOIN hasn't completed yet (i.e. is usable for mptcp) */
+ if (subflow->request_join && !subflow->fully_established)
+ return false;
+
+ /* only send if our side has not closed yet */
+ return ((1 << ssk->sk_state) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT));
+}
+
+#define MPTCP_SEND_BURST_SIZE ((1 << 16) - \
+ sizeof(struct tcphdr) - \
+ MAX_TCP_OPTION_SPACE - \
+ sizeof(struct ipv6hdr) - \
+ sizeof(struct frag_hdr))
+
+struct subflow_send_info {
+ struct sock *ssk;
+ u64 ratio;
+};
+
+static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk,
+ u32 *sndbuf)
+{
+ struct subflow_send_info send_info[2];
+ struct mptcp_subflow_context *subflow;
+ int i, nr_active = 0;
+ struct sock *ssk;
+ u64 ratio;
+ u32 pace;
+
+ sock_owned_by_me((struct sock *)msk);
+
+ *sndbuf = 0;
+ if (!mptcp_ext_cache_refill(msk))
+ return NULL;
+
+ if (__mptcp_check_fallback(msk)) {
+ if (!msk->first)
+ return NULL;
+ *sndbuf = msk->first->sk_sndbuf;
+ return sk_stream_memory_free(msk->first) ? msk->first : NULL;
+ }
+
+ /* re-use last subflow, if the burst allow that */
+ if (msk->last_snd && msk->snd_burst > 0 &&
+ sk_stream_memory_free(msk->last_snd) &&
+ mptcp_subflow_active(mptcp_subflow_ctx(msk->last_snd))) {
+ mptcp_for_each_subflow(msk, subflow) {
+ ssk = mptcp_subflow_tcp_sock(subflow);
+ *sndbuf = max(tcp_sk(ssk)->snd_wnd, *sndbuf);
+ }
+ return msk->last_snd;
+ }
+
+ /* pick the subflow with the lower wmem/wspace ratio */
+ for (i = 0; i < 2; ++i) {
+ send_info[i].ssk = NULL;
+ send_info[i].ratio = -1;
+ }
+ mptcp_for_each_subflow(msk, subflow) {
+ ssk = mptcp_subflow_tcp_sock(subflow);
+ if (!mptcp_subflow_active(subflow))
+ continue;
+
+ nr_active += !subflow->backup;
+ *sndbuf = max(tcp_sk(ssk)->snd_wnd, *sndbuf);
+ if (!sk_stream_memory_free(subflow->tcp_sock))
+ continue;
+
+ pace = READ_ONCE(ssk->sk_pacing_rate);
+ if (!pace)
+ continue;
+
+ ratio = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32,
+ pace);
+ if (ratio < send_info[subflow->backup].ratio) {
+ send_info[subflow->backup].ssk = ssk;
+ send_info[subflow->backup].ratio = ratio;
+ }
+ }
+
+ pr_debug("msk=%p nr_active=%d ssk=%p:%lld backup=%p:%lld",
+ msk, nr_active, send_info[0].ssk, send_info[0].ratio,
+ send_info[1].ssk, send_info[1].ratio);
+
+ /* pick the best backup if no other subflow is active */
+ if (!nr_active)
+ send_info[0].ssk = send_info[1].ssk;
+
+ if (send_info[0].ssk) {
+ msk->last_snd = send_info[0].ssk;
+ msk->snd_burst = min_t(int, MPTCP_SEND_BURST_SIZE,
+ sk_stream_wspace(msk->last_snd));
+ return msk->last_snd;
+ }
+ return NULL;
+}
+
+static void ssk_check_wmem(struct mptcp_sock *msk)
+{
+ if (unlikely(!mptcp_is_writeable(msk)))
+ mptcp_nospace(msk);
+}
+
+static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
+{
+ int mss_now = 0, size_goal = 0, ret = 0;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct page_frag *pfrag;
+ size_t copied = 0;
+ struct sock *ssk;
+ u32 sndbuf;
+ bool tx_ok;
+ long timeo;
+
+ if (msg->msg_flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL))
+ return -EOPNOTSUPP;
+
+ lock_sock(sk);
+
+ timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
+
+ if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
+ ret = sk_stream_wait_connect(sk, &timeo);
+ if (ret)
+ goto out;
+ }
+
+ pfrag = sk_page_frag(sk);
+restart:
+ mptcp_clean_una(sk);
+
+ if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) {
+ ret = -EPIPE;
+ goto out;
+ }
+
+ __mptcp_flush_join_list(msk);
+ ssk = mptcp_subflow_get_send(msk, &sndbuf);
+ while (!sk_stream_memory_free(sk) ||
+ !ssk ||
+ !mptcp_page_frag_refill(ssk, pfrag)) {
+ if (ssk) {
+ /* make sure retransmit timer is
+ * running before we wait for memory.
+ *
+ * The retransmit timer might be needed
+ * to make the peer send an up-to-date
+ * MPTCP Ack.
+ */
+ mptcp_set_timeout(sk, ssk);
+ if (!mptcp_timer_pending(sk))
+ mptcp_reset_timer(sk);
+ }
+
+ mptcp_nospace(msk);
+ ret = sk_stream_wait_memory(sk, &timeo);
+ if (ret)
+ goto out;
+
+ mptcp_clean_una(sk);
+
+ ssk = mptcp_subflow_get_send(msk, &sndbuf);
+ if (list_empty(&msk->conn_list)) {
+ ret = -ENOTCONN;
+ goto out;
+ }
+ }
+
+ /* do auto tuning */
+ if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK) &&
+ sndbuf > READ_ONCE(sk->sk_sndbuf))
+ WRITE_ONCE(sk->sk_sndbuf, sndbuf);
+
+ pr_debug("conn_list->subflow=%p", ssk);
+
+ lock_sock(ssk);
+ tx_ok = msg_data_left(msg);
+ while (tx_ok) {
+ ret = mptcp_sendmsg_frag(sk, ssk, msg, NULL, &timeo, &mss_now,
+ &size_goal);
+ if (ret < 0) {
+ if (ret == -EAGAIN && timeo > 0) {
+ mptcp_set_timeout(sk, ssk);
+ release_sock(ssk);
+ goto restart;
+ }
+ break;
+ }
+
+ /* burst can be negative, we will try move to the next subflow
+ * at selection time, if possible.
+ */
+ msk->snd_burst -= ret;
+ copied += ret;
+
+ tx_ok = msg_data_left(msg);
+ if (!tx_ok)
+ break;
+
+ if (!sk_stream_memory_free(ssk) ||
+ !mptcp_page_frag_refill(ssk, pfrag) ||
+ !mptcp_ext_cache_refill(msk)) {
+ tcp_push(ssk, msg->msg_flags, mss_now,
+ tcp_sk(ssk)->nonagle, size_goal);
+ mptcp_set_timeout(sk, ssk);
+ release_sock(ssk);
+ goto restart;
+ }
+
+ /* memory is charged to mptcp level socket as well, i.e.
+ * if msg is very large, mptcp socket may run out of buffer
+ * space. mptcp_clean_una() will release data that has
+ * been acked at mptcp level in the mean time, so there is
+ * a good chance we can continue sending data right away.
+ *
+ * Normally, when the tcp subflow can accept more data, then
+ * so can the MPTCP socket. However, we need to cope with
+ * peers that might lag behind in their MPTCP-level
+ * acknowledgements, i.e. data might have been acked at
+ * tcp level only. So, we must also check the MPTCP socket
+ * limits before we send more data.
+ */
+ if (unlikely(!sk_stream_memory_free(sk))) {
+ tcp_push(ssk, msg->msg_flags, mss_now,
+ tcp_sk(ssk)->nonagle, size_goal);
+ mptcp_clean_una(sk);
+ if (!sk_stream_memory_free(sk)) {
+ /* can't send more for now, need to wait for
+ * MPTCP-level ACKs from peer.
+ *
+ * Wakeup will happen via mptcp_clean_una().
+ */
+ mptcp_set_timeout(sk, ssk);
+ release_sock(ssk);
+ goto restart;
+ }
+ }
+ }
+
+ mptcp_set_timeout(sk, ssk);
+ if (copied) {
+ tcp_push(ssk, msg->msg_flags, mss_now, tcp_sk(ssk)->nonagle,
+ size_goal);
+
+ /* start the timer, if it's not pending */
+ if (!mptcp_timer_pending(sk))
+ mptcp_reset_timer(sk);
+ }
+
+ release_sock(ssk);
+out:
+ ssk_check_wmem(msk);
+ release_sock(sk);
+ return copied ? : ret;
+}
+
+static void mptcp_wait_data(struct sock *sk, long *timeo)
+{
+ DEFINE_WAIT_FUNC(wait, woken_wake_function);
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ add_wait_queue(sk_sleep(sk), &wait);
+ sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
+
+ sk_wait_event(sk, timeo,
+ test_and_clear_bit(MPTCP_DATA_READY, &msk->flags), &wait);
+
+ sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
+ remove_wait_queue(sk_sleep(sk), &wait);
+}
+
+static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk,
+ struct msghdr *msg,
+ size_t len)
+{
+ struct sock *sk = (struct sock *)msk;
+ struct sk_buff *skb;
+ int copied = 0;
+
+ while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
+ u32 offset = MPTCP_SKB_CB(skb)->offset;
+ u32 data_len = skb->len - offset;
+ u32 count = min_t(size_t, len - copied, data_len);
+ int err;
+
+ err = skb_copy_datagram_msg(skb, offset, msg, count);
+ if (unlikely(err < 0)) {
+ if (!copied)
+ return err;
+ break;
+ }
+
+ copied += count;
+
+ if (count < data_len) {
+ MPTCP_SKB_CB(skb)->offset += count;
+ break;
+ }
+
+ __skb_unlink(skb, &sk->sk_receive_queue);
+ __kfree_skb(skb);
+
+ if (copied >= len)
+ break;
+ }
+
+ return copied;
+}
+
+/* receive buffer autotuning. See tcp_rcv_space_adjust for more information.
+ *
+ * Only difference: Use highest rtt estimate of the subflows in use.
+ */
+static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied)
+{
+ struct mptcp_subflow_context *subflow;
+ struct sock *sk = (struct sock *)msk;
+ u32 time, advmss = 1;
+ u64 rtt_us, mstamp;
+
+ sock_owned_by_me(sk);
+
+ if (copied <= 0)
+ return;
+
+ msk->rcvq_space.copied += copied;
+
+ mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC);
+ time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time);
+
+ rtt_us = msk->rcvq_space.rtt_us;
+ if (rtt_us && time < (rtt_us >> 3))
+ return;
+
+ rtt_us = 0;
+ mptcp_for_each_subflow(msk, subflow) {
+ const struct tcp_sock *tp;
+ u64 sf_rtt_us;
+ u32 sf_advmss;
+
+ tp = tcp_sk(mptcp_subflow_tcp_sock(subflow));
+
+ sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us);
+ sf_advmss = READ_ONCE(tp->advmss);
+
+ rtt_us = max(sf_rtt_us, rtt_us);
+ advmss = max(sf_advmss, advmss);
+ }
+
+ msk->rcvq_space.rtt_us = rtt_us;
+ if (time < (rtt_us >> 3) || rtt_us == 0)
+ return;
+
+ if (msk->rcvq_space.copied <= msk->rcvq_space.space)
+ goto new_measure;
+
+ if (sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf &&
+ !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
+ int rcvmem, rcvbuf;
+ u64 rcvwin, grow;
+
+ rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss;
+
+ grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space);
+
+ do_div(grow, msk->rcvq_space.space);
+ rcvwin += (grow << 1);
+
+ rcvmem = SKB_TRUESIZE(advmss + MAX_TCP_HEADER);
+ while (tcp_win_from_space(sk, rcvmem) < advmss)
+ rcvmem += 128;
+
+ do_div(rcvwin, advmss);
+ rcvbuf = min_t(u64, rcvwin * rcvmem,
+ sock_net(sk)->ipv4.sysctl_tcp_rmem[2]);
+
+ if (rcvbuf > sk->sk_rcvbuf) {
+ u32 window_clamp;
+
+ window_clamp = tcp_win_from_space(sk, rcvbuf);
+ WRITE_ONCE(sk->sk_rcvbuf, rcvbuf);
+
+ /* Make subflows follow along. If we do not do this, we
+ * get drops at subflow level if skbs can't be moved to
+ * the mptcp rx queue fast enough (announced rcv_win can
+ * exceed ssk->sk_rcvbuf).
+ */
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk;
+ bool slow;
+
+ ssk = mptcp_subflow_tcp_sock(subflow);
+ slow = lock_sock_fast(ssk);
+ WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf);
+ tcp_sk(ssk)->window_clamp = window_clamp;
+ tcp_cleanup_rbuf(ssk, 1);
+ unlock_sock_fast(ssk, slow);
+ }
+ }
+ }
+
+ msk->rcvq_space.space = msk->rcvq_space.copied;
+new_measure:
+ msk->rcvq_space.copied = 0;
+ msk->rcvq_space.time = mstamp;
+}
+
+static bool __mptcp_move_skbs(struct mptcp_sock *msk)
+{
+ unsigned int moved = 0;
+ bool done;
+
+ /* avoid looping forever below on racing close */
+ if (((struct sock *)msk)->sk_state == TCP_CLOSE)
+ return false;
+
+ __mptcp_flush_join_list(msk);
+ do {
+ struct sock *ssk = mptcp_subflow_recv_lookup(msk);
+
+ if (!ssk)
+ break;
+
+ lock_sock(ssk);
+ done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
+ release_sock(ssk);
+ } while (!done);
+
+ if (mptcp_ofo_queue(msk) || moved > 0) {
+ mptcp_check_data_fin((struct sock *)msk);
+ return true;
+ }
+ return false;
+}
+
+static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
+ int nonblock, int flags, int *addr_len)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ int copied = 0;
+ int target;
+ long timeo;
+
+ if (msg->msg_flags & ~(MSG_WAITALL | MSG_DONTWAIT))
+ return -EOPNOTSUPP;
+
+ lock_sock(sk);
+ timeo = sock_rcvtimeo(sk, nonblock);
+
+ len = min_t(size_t, len, INT_MAX);
+ target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
+ __mptcp_flush_join_list(msk);
+
+ while (len > (size_t)copied) {
+ int bytes_read;
+
+ bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied);
+ if (unlikely(bytes_read < 0)) {
+ if (!copied)
+ copied = bytes_read;
+ goto out_err;
+ }
+
+ copied += bytes_read;
+
+ if (skb_queue_empty(&sk->sk_receive_queue) &&
+ __mptcp_move_skbs(msk))
+ continue;
+
+ /* only the master socket status is relevant here. The exit
+ * conditions mirror closely tcp_recvmsg()
+ */
+ if (copied >= target)
+ break;
+
+ if (copied) {
+ if (sk->sk_err ||
+ sk->sk_state == TCP_CLOSE ||
+ (sk->sk_shutdown & RCV_SHUTDOWN) ||
+ !timeo ||
+ signal_pending(current))
+ break;
+ } else {
+ if (sk->sk_err) {
+ copied = sock_error(sk);
+ break;
+ }
+
+ if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
+ mptcp_check_for_eof(msk);
+
+ if (sk->sk_shutdown & RCV_SHUTDOWN)
+ break;
+
+ if (sk->sk_state == TCP_CLOSE) {
+ copied = -ENOTCONN;
+ break;
+ }
+
+ if (!timeo) {
+ copied = -EAGAIN;
+ break;
+ }
+
+ if (signal_pending(current)) {
+ copied = sock_intr_errno(timeo);
+ break;
+ }
+ }
+
+ pr_debug("block timeout %ld", timeo);
+ mptcp_wait_data(sk, &timeo);
+ }
+
+ if (skb_queue_empty(&sk->sk_receive_queue)) {
+ /* entire backlog drained, clear DATA_READY. */
+ clear_bit(MPTCP_DATA_READY, &msk->flags);
+
+ /* .. race-breaker: ssk might have gotten new data
+ * after last __mptcp_move_skbs() returned false.
+ */
+ if (unlikely(__mptcp_move_skbs(msk)))
+ set_bit(MPTCP_DATA_READY, &msk->flags);
+ } else if (unlikely(!test_bit(MPTCP_DATA_READY, &msk->flags))) {
+ /* data to read but mptcp_wait_data() cleared DATA_READY */
+ set_bit(MPTCP_DATA_READY, &msk->flags);
+ }
+out_err:
+ pr_debug("msk=%p data_ready=%d rx queue empty=%d copied=%d",
+ msk, test_bit(MPTCP_DATA_READY, &msk->flags),
+ skb_queue_empty(&sk->sk_receive_queue), copied);
+ mptcp_rcv_space_adjust(msk, copied);
+
+ release_sock(sk);
+ return copied;
+}
+
+static void mptcp_retransmit_handler(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ if (atomic64_read(&msk->snd_una) == READ_ONCE(msk->write_seq)) {
+ mptcp_stop_timer(sk);
+ } else {
+ set_bit(MPTCP_WORK_RTX, &msk->flags);
+ if (schedule_work(&msk->work))
+ sock_hold(sk);
+ }
+}
+
+static void mptcp_retransmit_timer(struct timer_list *t)
+{
+ struct inet_connection_sock *icsk = from_timer(icsk, t,
+ icsk_retransmit_timer);
+ struct sock *sk = &icsk->icsk_inet.sk;
+
+ bh_lock_sock(sk);
+ if (!sock_owned_by_user(sk)) {
+ mptcp_retransmit_handler(sk);
+ } else {
+ /* delegate our work to tcp_release_cb() */
+ if (!test_and_set_bit(TCP_WRITE_TIMER_DEFERRED,
+ &sk->sk_tsq_flags))
+ sock_hold(sk);
+ }
+ bh_unlock_sock(sk);
+ sock_put(sk);
+}
+
+/* Find an idle subflow. Return NULL if there is unacked data at tcp
+ * level.
+ *
+ * A backup subflow is returned only if that is the only kind available.
+ */
+static struct sock *mptcp_subflow_get_retrans(const struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow;
+ struct sock *backup = NULL;
+
+ sock_owned_by_me((const struct sock *)msk);
+
+ if (__mptcp_check_fallback(msk))
+ return msk->first;
+
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ if (!mptcp_subflow_active(subflow))
+ continue;
+
+ /* still data outstanding at TCP level? Don't retransmit. */
+ if (!tcp_write_queue_empty(ssk)) {
+ if (inet_csk(ssk)->icsk_ca_state >= TCP_CA_Loss)
+ continue;
+ return NULL;
+ }
+
+ if (subflow->backup) {
+ if (!backup)
+ backup = ssk;
+ continue;
+ }
+
+ return ssk;
+ }
+
+ return backup;
+}
+
+/* subflow sockets can be either outgoing (connect) or incoming
+ * (accept).
+ *
+ * Outgoing subflows use in-kernel sockets.
+ * Incoming subflows do not have their own 'struct socket' allocated,
+ * so we need to use tcp_close() after detaching them from the mptcp
+ * parent socket.
+ */
+void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
+ struct mptcp_subflow_context *subflow,
+ long timeout)
+{
+ struct socket *sock = READ_ONCE(ssk->sk_socket);
+
+ list_del(&subflow->node);
+
+ if (sock && sock != sk->sk_socket) {
+ /* outgoing subflow */
+ sock_release(sock);
+ } else {
+ /* incoming subflow */
+ tcp_close(ssk, timeout);
+ }
+}
+
+static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu)
+{
+ return 0;
+}
+
+static void pm_work(struct mptcp_sock *msk)
+{
+ struct mptcp_pm_data *pm = &msk->pm;
+
+ spin_lock_bh(&msk->pm.lock);
+
+ pr_debug("msk=%p status=%x", msk, pm->status);
+ if (pm->status & BIT(MPTCP_PM_ADD_ADDR_RECEIVED)) {
+ pm->status &= ~BIT(MPTCP_PM_ADD_ADDR_RECEIVED);
+ mptcp_pm_nl_add_addr_received(msk);
+ }
+ if (pm->status & BIT(MPTCP_PM_RM_ADDR_RECEIVED)) {
+ pm->status &= ~BIT(MPTCP_PM_RM_ADDR_RECEIVED);
+ mptcp_pm_nl_rm_addr_received(msk);
+ }
+ if (pm->status & BIT(MPTCP_PM_ESTABLISHED)) {
+ pm->status &= ~BIT(MPTCP_PM_ESTABLISHED);
+ mptcp_pm_nl_fully_established(msk);
+ }
+ if (pm->status & BIT(MPTCP_PM_SUBFLOW_ESTABLISHED)) {
+ pm->status &= ~BIT(MPTCP_PM_SUBFLOW_ESTABLISHED);
+ mptcp_pm_nl_subflow_established(msk);
+ }
+
+ spin_unlock_bh(&msk->pm.lock);
+}
+
+static void __mptcp_close_subflow(struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow, *tmp;
+
+ list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ if (inet_sk_state_load(ssk) != TCP_CLOSE)
+ continue;
+
+ __mptcp_close_ssk((struct sock *)msk, ssk, subflow, 0);
+ }
+}
+
+static void mptcp_worker(struct work_struct *work)
+{
+ struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
+ struct sock *ssk, *sk = &msk->sk.icsk_inet.sk;
+ int orig_len, orig_offset, mss_now = 0, size_goal = 0;
+ struct mptcp_data_frag *dfrag;
+ u64 orig_write_seq;
+ size_t copied = 0;
+ struct msghdr msg = {
+ .msg_flags = MSG_DONTWAIT,
+ };
+ long timeo = 0;
+
+ lock_sock(sk);
+ mptcp_clean_una(sk);
+ mptcp_check_data_fin_ack(sk);
+ __mptcp_flush_join_list(msk);
+ if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
+ __mptcp_close_subflow(msk);
+
+ __mptcp_move_skbs(msk);
+
+ if (msk->pm.status)
+ pm_work(msk);
+
+ if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
+ mptcp_check_for_eof(msk);
+
+ mptcp_check_data_fin(sk);
+
+ if (!test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
+ goto unlock;
+
+ dfrag = mptcp_rtx_head(sk);
+ if (!dfrag)
+ goto unlock;
+
+ if (!mptcp_ext_cache_refill(msk))
+ goto reset_unlock;
+
+ ssk = mptcp_subflow_get_retrans(msk);
+ if (!ssk)
+ goto reset_unlock;
+
+ lock_sock(ssk);
+
+ orig_len = dfrag->data_len;
+ orig_offset = dfrag->offset;
+ orig_write_seq = dfrag->data_seq;
+ while (dfrag->data_len > 0) {
+ int ret = mptcp_sendmsg_frag(sk, ssk, &msg, dfrag, &timeo,
+ &mss_now, &size_goal);
+ if (ret < 0)
+ break;
+
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS);
+ copied += ret;
+ dfrag->data_len -= ret;
+ dfrag->offset += ret;
+
+ if (!mptcp_ext_cache_refill(msk))
+ break;
+ }
+ if (copied)
+ tcp_push(ssk, msg.msg_flags, mss_now, tcp_sk(ssk)->nonagle,
+ size_goal);
+
+ dfrag->data_seq = orig_write_seq;
+ dfrag->offset = orig_offset;
+ dfrag->data_len = orig_len;
+
+ mptcp_set_timeout(sk, ssk);
+ release_sock(ssk);
+
+reset_unlock:
+ if (!mptcp_timer_pending(sk))
+ mptcp_reset_timer(sk);
+
+unlock:
+ release_sock(sk);
+ sock_put(sk);
+}
+
+static int __mptcp_init_sock(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ spin_lock_init(&msk->join_list_lock);
+
+ INIT_LIST_HEAD(&msk->conn_list);
+ INIT_LIST_HEAD(&msk->join_list);
+ INIT_LIST_HEAD(&msk->rtx_queue);
+ __set_bit(MPTCP_SEND_SPACE, &msk->flags);
+ INIT_WORK(&msk->work, mptcp_worker);
+ msk->out_of_order_queue = RB_ROOT;
+
+ msk->first = NULL;
+ inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss;
+
+ mptcp_pm_data_init(msk);
+
+ /* re-use the csk retrans timer for MPTCP-level retrans */
+ timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0);
+
+ return 0;
+}
+
+static int mptcp_init_sock(struct sock *sk)
+{
+ struct net *net = sock_net(sk);
+ int ret;
+
+ ret = __mptcp_init_sock(sk);
+ if (ret)
+ return ret;
+
+ if (!mptcp_is_enabled(net))
+ return -ENOPROTOOPT;
+
+ if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net))
+ return -ENOMEM;
+
+ ret = __mptcp_socket_create(mptcp_sk(sk));
+ if (ret)
+ return ret;
+
+ sk_sockets_allocated_inc(sk);
+ sk->sk_rcvbuf = sock_net(sk)->ipv4.sysctl_tcp_rmem[1];
+ sk->sk_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[1];
+
+ return 0;
+}
+
+static void __mptcp_clear_xmit(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct mptcp_data_frag *dtmp, *dfrag;
+
+ sk_stop_timer(sk, &msk->sk.icsk_retransmit_timer);
+
+ list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list)
+ dfrag_clear(sk, dfrag);
+}
+
+static void mptcp_cancel_work(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ if (cancel_work_sync(&msk->work))
+ sock_put(sk);
+}
+
+void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how)
+{
+ lock_sock(ssk);
+
+ switch (ssk->sk_state) {
+ case TCP_LISTEN:
+ if (!(how & RCV_SHUTDOWN))
+ break;
+ fallthrough;
+ case TCP_SYN_SENT:
+ tcp_disconnect(ssk, O_NONBLOCK);
+ break;
+ default:
+ if (__mptcp_check_fallback(mptcp_sk(sk))) {
+ pr_debug("Fallback");
+ ssk->sk_shutdown |= how;
+ tcp_shutdown(ssk, how);
+ } else {
+ pr_debug("Sending DATA_FIN on subflow %p", ssk);
+ mptcp_set_timeout(sk, ssk);
+ tcp_send_ack(ssk);
+ }
+ break;
+ }
+
+ release_sock(ssk);
+}
+
+static const unsigned char new_state[16] = {
+ /* current state: new state: action: */
+ [0 /* (Invalid) */] = TCP_CLOSE,
+ [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
+ [TCP_SYN_SENT] = TCP_CLOSE,
+ [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
+ [TCP_FIN_WAIT1] = TCP_FIN_WAIT1,
+ [TCP_FIN_WAIT2] = TCP_FIN_WAIT2,
+ [TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */
+ [TCP_CLOSE] = TCP_CLOSE,
+ [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN,
+ [TCP_LAST_ACK] = TCP_LAST_ACK,
+ [TCP_LISTEN] = TCP_CLOSE,
+ [TCP_CLOSING] = TCP_CLOSING,
+ [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */
+};
+
+static int mptcp_close_state(struct sock *sk)
+{
+ int next = (int)new_state[sk->sk_state];
+ int ns = next & TCP_STATE_MASK;
+
+ inet_sk_state_store(sk, ns);
+
+ return next & TCP_ACTION_FIN;
+}
+
+static void mptcp_close(struct sock *sk, long timeout)
+{
+ struct mptcp_subflow_context *subflow, *tmp;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ LIST_HEAD(conn_list);
+
+ lock_sock(sk);
+ sk->sk_shutdown = SHUTDOWN_MASK;
+
+ if (sk->sk_state == TCP_LISTEN) {
+ inet_sk_state_store(sk, TCP_CLOSE);
+ goto cleanup;
+ } else if (sk->sk_state == TCP_CLOSE) {
+ goto cleanup;
+ }
+
+ if (__mptcp_check_fallback(msk)) {
+ goto update_state;
+ } else if (mptcp_close_state(sk)) {
+ pr_debug("Sending DATA_FIN sk=%p", sk);
+ WRITE_ONCE(msk->write_seq, msk->write_seq + 1);
+ WRITE_ONCE(msk->snd_data_fin_enable, 1);
+
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
+
+ mptcp_subflow_shutdown(sk, tcp_sk, SHUTDOWN_MASK);
+ }
+ }
+
+ sk_stream_wait_close(sk, timeout);
+
+update_state:
+ inet_sk_state_store(sk, TCP_CLOSE);
+
+cleanup:
+ /* be sure to always acquire the join list lock, to sync vs
+ * mptcp_finish_join().
+ */
+ spin_lock_bh(&msk->join_list_lock);
+ list_splice_tail_init(&msk->join_list, &msk->conn_list);
+ spin_unlock_bh(&msk->join_list_lock);
+ list_splice_init(&msk->conn_list, &conn_list);
+
+ __mptcp_clear_xmit(sk);
+
+ release_sock(sk);
+
+ list_for_each_entry_safe(subflow, tmp, &conn_list, node) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+ __mptcp_close_ssk(sk, ssk, subflow, timeout);
+ }
+
+ mptcp_cancel_work(sk);
+
+ __skb_queue_purge(&sk->sk_receive_queue);
+
+ sk_common_release(sk);
+}
+
+static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk)
+{
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ const struct ipv6_pinfo *ssk6 = inet6_sk(ssk);
+ struct ipv6_pinfo *msk6 = inet6_sk(msk);
+
+ msk->sk_v6_daddr = ssk->sk_v6_daddr;
+ msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr;
+
+ if (msk6 && ssk6) {
+ msk6->saddr = ssk6->saddr;
+ msk6->flow_label = ssk6->flow_label;
+ }
+#endif
+
+ inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num;
+ inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport;
+ inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport;
+ inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr;
+ inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr;
+ inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr;
+}
+
+static int mptcp_disconnect(struct sock *sk, int flags)
+{
+ /* Should never be called.
+ * inet_stream_connect() calls ->disconnect, but that
+ * refers to the subflow socket, not the mptcp one.
+ */
+ WARN_ON_ONCE(1);
+ return 0;
+}
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk)
+{
+ unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo);
+
+ return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
+}
+#endif
+
+struct sock *mptcp_sk_clone(const struct sock *sk,
+ const struct mptcp_options_received *mp_opt,
+ struct request_sock *req)
+{
+ struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
+ struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC);
+ struct mptcp_sock *msk;
+ u64 ack_seq;
+
+ if (!nsk)
+ return NULL;
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ if (nsk->sk_family == AF_INET6)
+ inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk);
+#endif
+
+ __mptcp_init_sock(nsk);
+
+ msk = mptcp_sk(nsk);
+ msk->local_key = subflow_req->local_key;
+ msk->token = subflow_req->token;
+ msk->subflow = NULL;
+ WRITE_ONCE(msk->fully_established, false);
+
+ msk->write_seq = subflow_req->idsn + 1;
+ atomic64_set(&msk->snd_una, msk->write_seq);
+ if (mp_opt->mp_capable) {
+ msk->can_ack = true;
+ msk->remote_key = mp_opt->sndr_key;
+ mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq);
+ ack_seq++;
+ WRITE_ONCE(msk->ack_seq, ack_seq);
+ }
+
+ sock_reset_flag(nsk, SOCK_RCU_FREE);
+ /* will be fully established after successful MPC subflow creation */
+ inet_sk_state_store(nsk, TCP_SYN_RECV);
+
+ security_inet_csk_clone(nsk, req);
+ bh_unlock_sock(nsk);
+
+ /* keep a single reference */
+ __sock_put(nsk);
+ return nsk;
+}
+
+void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk)
+{
+ const struct tcp_sock *tp = tcp_sk(ssk);
+
+ msk->rcvq_space.copied = 0;
+ msk->rcvq_space.rtt_us = 0;
+
+ msk->rcvq_space.time = tp->tcp_mstamp;
+
+ /* initial rcv_space offering made to peer */
+ msk->rcvq_space.space = min_t(u32, tp->rcv_wnd,
+ TCP_INIT_CWND * tp->advmss);
+ if (msk->rcvq_space.space == 0)
+ msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT;
+}
+
+static struct sock *mptcp_accept(struct sock *sk, int flags, int *err,
+ bool kern)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct socket *listener;
+ struct sock *newsk;
+
+ listener = __mptcp_nmpc_socket(msk);
+ if (WARN_ON_ONCE(!listener)) {
+ *err = -EINVAL;
+ return NULL;
+ }
+
+ pr_debug("msk=%p, listener=%p", msk, mptcp_subflow_ctx(listener->sk));
+ newsk = inet_csk_accept(listener->sk, flags, err, kern);
+ if (!newsk)
+ return NULL;
+
+ pr_debug("msk=%p, subflow is mptcp=%d", msk, sk_is_mptcp(newsk));
+ if (sk_is_mptcp(newsk)) {
+ struct mptcp_subflow_context *subflow;
+ struct sock *new_mptcp_sock;
+ struct sock *ssk = newsk;
+
+ subflow = mptcp_subflow_ctx(newsk);
+ new_mptcp_sock = subflow->conn;
+
+ /* is_mptcp should be false if subflow->conn is missing, see
+ * subflow_syn_recv_sock()
+ */
+ if (WARN_ON_ONCE(!new_mptcp_sock)) {
+ tcp_sk(newsk)->is_mptcp = 0;
+ goto out;
+ }
+
+ /* acquire the 2nd reference for the owning socket */
+ sock_hold(new_mptcp_sock);
+
+ local_bh_disable();
+ bh_lock_sock(new_mptcp_sock);
+ msk = mptcp_sk(new_mptcp_sock);
+ msk->first = newsk;
+
+ newsk = new_mptcp_sock;
+ mptcp_copy_inaddrs(newsk, ssk);
+ list_add(&subflow->node, &msk->conn_list);
+
+ mptcp_rcv_space_init(msk, ssk);
+ bh_unlock_sock(new_mptcp_sock);
+
+ __MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEPASSIVEACK);
+ local_bh_enable();
+ } else {
+ MPTCP_INC_STATS(sock_net(sk),
+ MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK);
+ }
+
+out:
+ newsk->sk_kern_sock = kern;
+ return newsk;
+}
+
+void mptcp_destroy_common(struct mptcp_sock *msk)
+{
+ skb_rbtree_purge(&msk->out_of_order_queue);
+ mptcp_token_destroy(msk);
+ mptcp_pm_free_anno_list(msk);
+}
+
+static void mptcp_destroy(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ if (msk->cached_ext)
+ __skb_ext_put(msk->cached_ext);
+
+ mptcp_destroy_common(msk);
+ sk_sockets_allocated_dec(sk);
+}
+
+static int mptcp_setsockopt_sol_socket(struct mptcp_sock *msk, int optname,
+ sockptr_t optval, unsigned int optlen)
+{
+ struct sock *sk = (struct sock *)msk;
+ struct socket *ssock;
+ int ret;
+
+ switch (optname) {
+ case SO_REUSEPORT:
+ case SO_REUSEADDR:
+ lock_sock(sk);
+ ssock = __mptcp_nmpc_socket(msk);
+ if (!ssock) {
+ release_sock(sk);
+ return -EINVAL;
+ }
+
+ ret = sock_setsockopt(ssock, SOL_SOCKET, optname, optval, optlen);
+ if (ret == 0) {
+ if (optname == SO_REUSEPORT)
+ sk->sk_reuseport = ssock->sk->sk_reuseport;
+ else if (optname == SO_REUSEADDR)
+ sk->sk_reuse = ssock->sk->sk_reuse;
+ }
+ release_sock(sk);
+ return ret;
+ }
+
+ return sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname, optval, optlen);
+}
+
+static int mptcp_setsockopt_v6(struct mptcp_sock *msk, int optname,
+ sockptr_t optval, unsigned int optlen)
+{
+ struct sock *sk = (struct sock *)msk;
+ int ret = -EOPNOTSUPP;
+ struct socket *ssock;
+
+ switch (optname) {
+ case IPV6_V6ONLY:
+ lock_sock(sk);
+ ssock = __mptcp_nmpc_socket(msk);
+ if (!ssock) {
+ release_sock(sk);
+ return -EINVAL;
+ }
+
+ ret = tcp_setsockopt(ssock->sk, SOL_IPV6, optname, optval, optlen);
+ if (ret == 0)
+ sk->sk_ipv6only = ssock->sk->sk_ipv6only;
+
+ release_sock(sk);
+ break;
+ }
+
+ return ret;
+}
+
+static bool mptcp_unsupported(int level, int optname)
+{
+ if (level == SOL_IP) {
+ switch (optname) {
+ case IP_ADD_MEMBERSHIP:
+ case IP_ADD_SOURCE_MEMBERSHIP:
+ case IP_DROP_MEMBERSHIP:
+ case IP_DROP_SOURCE_MEMBERSHIP:
+ case IP_BLOCK_SOURCE:
+ case IP_UNBLOCK_SOURCE:
+ case MCAST_JOIN_GROUP:
+ case MCAST_LEAVE_GROUP:
+ case MCAST_JOIN_SOURCE_GROUP:
+ case MCAST_LEAVE_SOURCE_GROUP:
+ case MCAST_BLOCK_SOURCE:
+ case MCAST_UNBLOCK_SOURCE:
+ case MCAST_MSFILTER:
+ return true;
+ }
+ return false;
+ }
+ if (level == SOL_IPV6) {
+ switch (optname) {
+ case IPV6_ADDRFORM:
+ case IPV6_ADD_MEMBERSHIP:
+ case IPV6_DROP_MEMBERSHIP:
+ case IPV6_JOIN_ANYCAST:
+ case IPV6_LEAVE_ANYCAST:
+ case MCAST_JOIN_GROUP:
+ case MCAST_LEAVE_GROUP:
+ case MCAST_JOIN_SOURCE_GROUP:
+ case MCAST_LEAVE_SOURCE_GROUP:
+ case MCAST_BLOCK_SOURCE:
+ case MCAST_UNBLOCK_SOURCE:
+ case MCAST_MSFILTER:
+ return true;
+ }
+ return false;
+ }
+ return false;
+}
+
+static int mptcp_setsockopt(struct sock *sk, int level, int optname,
+ sockptr_t optval, unsigned int optlen)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct sock *ssk;
+
+ pr_debug("msk=%p", msk);
+
+ if (mptcp_unsupported(level, optname))
+ return -ENOPROTOOPT;
+
+ if (level == SOL_SOCKET)
+ return mptcp_setsockopt_sol_socket(msk, optname, optval, optlen);
+
+ /* @@ the meaning of setsockopt() when the socket is connected and
+ * there are multiple subflows is not yet defined. It is up to the
+ * MPTCP-level socket to configure the subflows until the subflow
+ * is in TCP fallback, when TCP socket options are passed through
+ * to the one remaining subflow.
+ */
+ lock_sock(sk);
+ ssk = __mptcp_tcp_fallback(msk);
+ release_sock(sk);
+ if (ssk)
+ return tcp_setsockopt(ssk, level, optname, optval, optlen);
+
+ if (level == SOL_IPV6)
+ return mptcp_setsockopt_v6(msk, optname, optval, optlen);
+
+ return -EOPNOTSUPP;
+}
+
+static int mptcp_getsockopt(struct sock *sk, int level, int optname,
+ char __user *optval, int __user *option)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct sock *ssk;
+
+ pr_debug("msk=%p", msk);
+
+ /* @@ the meaning of setsockopt() when the socket is connected and
+ * there are multiple subflows is not yet defined. It is up to the
+ * MPTCP-level socket to configure the subflows until the subflow
+ * is in TCP fallback, when socket options are passed through
+ * to the one remaining subflow.
+ */
+ lock_sock(sk);
+ ssk = __mptcp_tcp_fallback(msk);
+ release_sock(sk);
+ if (ssk)
+ return tcp_getsockopt(ssk, level, optname, optval, option);
+
+ return -EOPNOTSUPP;
+}
+
+#define MPTCP_DEFERRED_ALL (TCPF_DELACK_TIMER_DEFERRED | \
+ TCPF_WRITE_TIMER_DEFERRED)
+
+/* this is very alike tcp_release_cb() but we must handle differently a
+ * different set of events
+ */
+static void mptcp_release_cb(struct sock *sk)
+{
+ unsigned long flags, nflags;
+
+ do {
+ flags = sk->sk_tsq_flags;
+ if (!(flags & MPTCP_DEFERRED_ALL))
+ return;
+ nflags = flags & ~MPTCP_DEFERRED_ALL;
+ } while (cmpxchg(&sk->sk_tsq_flags, flags, nflags) != flags);
+
+ sock_release_ownership(sk);
+
+ if (flags & TCPF_DELACK_TIMER_DEFERRED) {
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct sock *ssk;
+
+ ssk = mptcp_subflow_recv_lookup(msk);
+ if (!ssk || !schedule_work(&msk->work))
+ __sock_put(sk);
+ }
+
+ if (flags & TCPF_WRITE_TIMER_DEFERRED) {
+ mptcp_retransmit_handler(sk);
+ __sock_put(sk);
+ }
+}
+
+static int mptcp_hash(struct sock *sk)
+{
+ /* should never be called,
+ * we hash the TCP subflows not the master socket
+ */
+ WARN_ON_ONCE(1);
+ return 0;
+}
+
+static void mptcp_unhash(struct sock *sk)
+{
+ /* called from sk_common_release(), but nothing to do here */
+}
+
+static int mptcp_get_port(struct sock *sk, unsigned short snum)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct socket *ssock;
+
+ ssock = __mptcp_nmpc_socket(msk);
+ pr_debug("msk=%p, subflow=%p", msk, ssock);
+ if (WARN_ON_ONCE(!ssock))
+ return -EINVAL;
+
+ return inet_csk_get_port(ssock->sk, snum);
+}
+
+void mptcp_finish_connect(struct sock *ssk)
+{
+ struct mptcp_subflow_context *subflow;
+ struct mptcp_sock *msk;
+ struct sock *sk;
+ u64 ack_seq;
+
+ subflow = mptcp_subflow_ctx(ssk);
+ sk = subflow->conn;
+ msk = mptcp_sk(sk);
+
+ pr_debug("msk=%p, token=%u", sk, subflow->token);
+
+ mptcp_crypto_key_sha(subflow->remote_key, NULL, &ack_seq);
+ ack_seq++;
+ subflow->map_seq = ack_seq;
+ subflow->map_subflow_seq = 1;
+
+ /* the socket is not connected yet, no msk/subflow ops can access/race
+ * accessing the field below
+ */
+ WRITE_ONCE(msk->remote_key, subflow->remote_key);
+ WRITE_ONCE(msk->local_key, subflow->local_key);
+ WRITE_ONCE(msk->write_seq, subflow->idsn + 1);
+ WRITE_ONCE(msk->ack_seq, ack_seq);
+ WRITE_ONCE(msk->can_ack, 1);
+ atomic64_set(&msk->snd_una, msk->write_seq);
+
+ mptcp_pm_new_connection(msk, 0);
+
+ mptcp_rcv_space_init(msk, ssk);
+}
+
+static void mptcp_sock_graft(struct sock *sk, struct socket *parent)
+{
+ write_lock_bh(&sk->sk_callback_lock);
+ rcu_assign_pointer(sk->sk_wq, &parent->wq);
+ sk_set_socket(sk, parent);
+ sk->sk_uid = SOCK_INODE(parent)->i_uid;
+ write_unlock_bh(&sk->sk_callback_lock);
+}
+
+bool mptcp_finish_join(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct mptcp_sock *msk = mptcp_sk(subflow->conn);
+ struct sock *parent = (void *)msk;
+ struct socket *parent_sock;
+ bool ret;
+
+ pr_debug("msk=%p, subflow=%p", msk, subflow);
+
+ /* mptcp socket already closing? */
+ if (!mptcp_is_fully_established(parent))
+ return false;
+
+ if (!msk->pm.server_side)
+ return true;
+
+ if (!mptcp_pm_allow_new_subflow(msk))
+ return false;
+
+ /* active connections are already on conn_list, and we can't acquire
+ * msk lock here.
+ * use the join list lock as synchronization point and double-check
+ * msk status to avoid racing with mptcp_close()
+ */
+ spin_lock_bh(&msk->join_list_lock);
+ ret = inet_sk_state_load(parent) == TCP_ESTABLISHED;
+ if (ret && !WARN_ON_ONCE(!list_empty(&subflow->node)))
+ list_add_tail(&subflow->node, &msk->join_list);
+ spin_unlock_bh(&msk->join_list_lock);
+ if (!ret)
+ return false;
+
+ /* attach to msk socket only after we are sure he will deal with us
+ * at close time
+ */
+ parent_sock = READ_ONCE(parent->sk_socket);
+ if (parent_sock && !sk->sk_socket)
+ mptcp_sock_graft(sk, parent_sock);
+ subflow->map_seq = READ_ONCE(msk->ack_seq);
+ return true;
+}
+
+static bool mptcp_memory_free(const struct sock *sk, int wake)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ return wake ? test_bit(MPTCP_SEND_SPACE, &msk->flags) : true;
+}
+
+static struct proto mptcp_prot = {
+ .name = "MPTCP",
+ .owner = THIS_MODULE,
+ .init = mptcp_init_sock,
+ .disconnect = mptcp_disconnect,
+ .close = mptcp_close,
+ .accept = mptcp_accept,
+ .setsockopt = mptcp_setsockopt,
+ .getsockopt = mptcp_getsockopt,
+ .shutdown = tcp_shutdown,
+ .destroy = mptcp_destroy,
+ .sendmsg = mptcp_sendmsg,
+ .recvmsg = mptcp_recvmsg,
+ .release_cb = mptcp_release_cb,
+ .hash = mptcp_hash,
+ .unhash = mptcp_unhash,
+ .get_port = mptcp_get_port,
+ .sockets_allocated = &mptcp_sockets_allocated,
+ .memory_allocated = &tcp_memory_allocated,
+ .memory_pressure = &tcp_memory_pressure,
+ .stream_memory_free = mptcp_memory_free,
+ .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
+ .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
+ .sysctl_mem = sysctl_tcp_mem,
+ .obj_size = sizeof(struct mptcp_sock),
+ .slab_flags = SLAB_TYPESAFE_BY_RCU,
+ .no_autobind = true,
+};
+
+static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
+{
+ struct mptcp_sock *msk = mptcp_sk(sock->sk);
+ struct socket *ssock;
+ int err;
+
+ lock_sock(sock->sk);
+ ssock = __mptcp_nmpc_socket(msk);
+ if (!ssock) {
+ err = -EINVAL;
+ goto unlock;
+ }
+
+ err = ssock->ops->bind(ssock, uaddr, addr_len);
+ if (!err)
+ mptcp_copy_inaddrs(sock->sk, ssock->sk);
+
+unlock:
+ release_sock(sock->sk);
+ return err;
+}
+
+static void mptcp_subflow_early_fallback(struct mptcp_sock *msk,
+ struct mptcp_subflow_context *subflow)
+{
+ subflow->request_mptcp = 0;
+ __mptcp_do_fallback(msk);
+}
+
+static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
+ int addr_len, int flags)
+{
+ struct mptcp_sock *msk = mptcp_sk(sock->sk);
+ struct mptcp_subflow_context *subflow;
+ struct socket *ssock;
+ int err;
+
+ lock_sock(sock->sk);
+ if (sock->state != SS_UNCONNECTED && msk->subflow) {
+ /* pending connection or invalid state, let existing subflow
+ * cope with that
+ */
+ ssock = msk->subflow;
+ goto do_connect;
+ }
+
+ ssock = __mptcp_nmpc_socket(msk);
+ if (!ssock) {
+ err = -EINVAL;
+ goto unlock;
+ }
+
+ mptcp_token_destroy(msk);
+ inet_sk_state_store(sock->sk, TCP_SYN_SENT);
+ subflow = mptcp_subflow_ctx(ssock->sk);
+#ifdef CONFIG_TCP_MD5SIG
+ /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
+ * TCP option space.
+ */
+ if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info))
+ mptcp_subflow_early_fallback(msk, subflow);
+#endif
+ if (subflow->request_mptcp && mptcp_token_new_connect(ssock->sk))
+ mptcp_subflow_early_fallback(msk, subflow);
+
+do_connect:
+ err = ssock->ops->connect(ssock, uaddr, addr_len, flags);
+ sock->state = ssock->state;
+
+ /* on successful connect, the msk state will be moved to established by
+ * subflow_finish_connect()
+ */
+ if (!err || err == -EINPROGRESS)
+ mptcp_copy_inaddrs(sock->sk, ssock->sk);
+ else
+ inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
+
+unlock:
+ release_sock(sock->sk);
+ return err;
+}
+
+static int mptcp_listen(struct socket *sock, int backlog)
+{
+ struct mptcp_sock *msk = mptcp_sk(sock->sk);
+ struct socket *ssock;
+ int err;
+
+ pr_debug("msk=%p", msk);
+
+ lock_sock(sock->sk);
+ ssock = __mptcp_nmpc_socket(msk);
+ if (!ssock) {
+ err = -EINVAL;
+ goto unlock;
+ }
+
+ mptcp_token_destroy(msk);
+ inet_sk_state_store(sock->sk, TCP_LISTEN);
+ sock_set_flag(sock->sk, SOCK_RCU_FREE);
+
+ err = ssock->ops->listen(ssock, backlog);
+ inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
+ if (!err)
+ mptcp_copy_inaddrs(sock->sk, ssock->sk);
+
+unlock:
+ release_sock(sock->sk);
+ return err;
+}
+
+static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
+ int flags, bool kern)
+{
+ struct mptcp_sock *msk = mptcp_sk(sock->sk);
+ struct socket *ssock;
+ int err;
+
+ pr_debug("msk=%p", msk);
+
+ lock_sock(sock->sk);
+ if (sock->sk->sk_state != TCP_LISTEN)
+ goto unlock_fail;
+
+ ssock = __mptcp_nmpc_socket(msk);
+ if (!ssock)
+ goto unlock_fail;
+
+ clear_bit(MPTCP_DATA_READY, &msk->flags);
+ sock_hold(ssock->sk);
+ release_sock(sock->sk);
+
+ err = ssock->ops->accept(sock, newsock, flags, kern);
+ if (err == 0 && !mptcp_is_tcpsk(newsock->sk)) {
+ struct mptcp_sock *msk = mptcp_sk(newsock->sk);
+ struct mptcp_subflow_context *subflow;
+
+ /* set ssk->sk_socket of accept()ed flows to mptcp socket.
+ * This is needed so NOSPACE flag can be set from tcp stack.
+ */
+ __mptcp_flush_join_list(msk);
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ if (!ssk->sk_socket)
+ mptcp_sock_graft(ssk, newsock);
+ }
+ }
+
+ if (inet_csk_listen_poll(ssock->sk))
+ set_bit(MPTCP_DATA_READY, &msk->flags);
+ sock_put(ssock->sk);
+ return err;
+
+unlock_fail:
+ release_sock(sock->sk);
+ return -EINVAL;
+}
+
+static __poll_t mptcp_check_readable(struct mptcp_sock *msk)
+{
+ return test_bit(MPTCP_DATA_READY, &msk->flags) ? EPOLLIN | EPOLLRDNORM :
+ 0;
+}
+
+static __poll_t mptcp_poll(struct file *file, struct socket *sock,
+ struct poll_table_struct *wait)
+{
+ struct sock *sk = sock->sk;
+ struct mptcp_sock *msk;
+ __poll_t mask = 0;
+ int state;
+
+ msk = mptcp_sk(sk);
+ sock_poll_wait(file, sock, wait);
+
+ state = inet_sk_state_load(sk);
+ pr_debug("msk=%p state=%d flags=%lx", msk, state, msk->flags);
+ if (state == TCP_LISTEN)
+ return mptcp_check_readable(msk);
+
+ if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) {
+ mask |= mptcp_check_readable(msk);
+ if (test_bit(MPTCP_SEND_SPACE, &msk->flags))
+ mask |= EPOLLOUT | EPOLLWRNORM;
+ }
+ if (sk->sk_shutdown & RCV_SHUTDOWN)
+ mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
+
+ return mask;
+}
+
+static int mptcp_shutdown(struct socket *sock, int how)
+{
+ struct mptcp_sock *msk = mptcp_sk(sock->sk);
+ struct mptcp_subflow_context *subflow;
+ int ret = 0;
+
+ pr_debug("sk=%p, how=%d", msk, how);
+
+ lock_sock(sock->sk);
+
+ how++;
+ if ((how & ~SHUTDOWN_MASK) || !how) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+
+ if (sock->state == SS_CONNECTING) {
+ if ((1 << sock->sk->sk_state) &
+ (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE))
+ sock->state = SS_DISCONNECTING;
+ else
+ sock->state = SS_CONNECTED;
+ }
+
+ /* If we've already sent a FIN, or it's a closed state, skip this. */
+ if (__mptcp_check_fallback(msk)) {
+ if (how == SHUT_WR || how == SHUT_RDWR)
+ inet_sk_state_store(sock->sk, TCP_FIN_WAIT1);
+
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
+
+ mptcp_subflow_shutdown(sock->sk, tcp_sk, how);
+ }
+ } else if ((how & SEND_SHUTDOWN) &&
+ ((1 << sock->sk->sk_state) &
+ (TCPF_ESTABLISHED | TCPF_SYN_SENT |
+ TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) &&
+ mptcp_close_state(sock->sk)) {
+ __mptcp_flush_join_list(msk);
+
+ WRITE_ONCE(msk->write_seq, msk->write_seq + 1);
+ WRITE_ONCE(msk->snd_data_fin_enable, 1);
+
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
+
+ mptcp_subflow_shutdown(sock->sk, tcp_sk, how);
+ }
+ }
+
+ /* Wake up anyone sleeping in poll. */
+ sock->sk->sk_state_change(sock->sk);
+
+out_unlock:
+ release_sock(sock->sk);
+
+ return ret;
+}
+
+static const struct proto_ops mptcp_stream_ops = {
+ .family = PF_INET,
+ .owner = THIS_MODULE,
+ .release = inet_release,
+ .bind = mptcp_bind,
+ .connect = mptcp_stream_connect,
+ .socketpair = sock_no_socketpair,
+ .accept = mptcp_stream_accept,
+ .getname = inet_getname,
+ .poll = mptcp_poll,
+ .ioctl = inet_ioctl,
+ .gettstamp = sock_gettstamp,
+ .listen = mptcp_listen,
+ .shutdown = mptcp_shutdown,
+ .setsockopt = sock_common_setsockopt,
+ .getsockopt = sock_common_getsockopt,
+ .sendmsg = inet_sendmsg,
+ .recvmsg = inet_recvmsg,
+ .mmap = sock_no_mmap,
+ .sendpage = inet_sendpage,
+};
+
+static struct inet_protosw mptcp_protosw = {
+ .type = SOCK_STREAM,
+ .protocol = IPPROTO_MPTCP,
+ .prot = &mptcp_prot,
+ .ops = &mptcp_stream_ops,
+ .flags = INET_PROTOSW_ICSK,
+};
+
+void __init mptcp_proto_init(void)
+{
+ mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo;
+
+ if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL))
+ panic("Failed to allocate MPTCP pcpu counter\n");
+
+ mptcp_subflow_init();
+ mptcp_pm_init();
+ mptcp_token_init();
+
+ if (proto_register(&mptcp_prot, 1) != 0)
+ panic("Failed to register MPTCP proto.\n");
+
+ inet_register_protosw(&mptcp_protosw);
+
+ BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb));
+}
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+static const struct proto_ops mptcp_v6_stream_ops = {
+ .family = PF_INET6,
+ .owner = THIS_MODULE,
+ .release = inet6_release,
+ .bind = mptcp_bind,
+ .connect = mptcp_stream_connect,
+ .socketpair = sock_no_socketpair,
+ .accept = mptcp_stream_accept,
+ .getname = inet6_getname,
+ .poll = mptcp_poll,
+ .ioctl = inet6_ioctl,
+ .gettstamp = sock_gettstamp,
+ .listen = mptcp_listen,
+ .shutdown = mptcp_shutdown,
+ .setsockopt = sock_common_setsockopt,
+ .getsockopt = sock_common_getsockopt,
+ .sendmsg = inet6_sendmsg,
+ .recvmsg = inet6_recvmsg,
+ .mmap = sock_no_mmap,
+ .sendpage = inet_sendpage,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = inet6_compat_ioctl,
+#endif
+};
+
+static struct proto mptcp_v6_prot;
+
+static void mptcp_v6_destroy(struct sock *sk)
+{
+ mptcp_destroy(sk);
+ inet6_destroy_sock(sk);
+}
+
+static struct inet_protosw mptcp_v6_protosw = {
+ .type = SOCK_STREAM,
+ .protocol = IPPROTO_MPTCP,
+ .prot = &mptcp_v6_prot,
+ .ops = &mptcp_v6_stream_ops,
+ .flags = INET_PROTOSW_ICSK,
+};
+
+int __init mptcp_proto_v6_init(void)
+{
+ int err;
+
+ mptcp_v6_prot = mptcp_prot;
+ strcpy(mptcp_v6_prot.name, "MPTCPv6");
+ mptcp_v6_prot.slab = NULL;
+ mptcp_v6_prot.destroy = mptcp_v6_destroy;
+ mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock);
+
+ err = proto_register(&mptcp_v6_prot, 1);
+ if (err)
+ return err;
+
+ err = inet6_register_protosw(&mptcp_v6_protosw);
+ if (err)
+ proto_unregister(&mptcp_v6_prot);
+
+ return err;
+}
+#endif