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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /net/mptcp/protocol.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'net/mptcp/protocol.c')
-rw-r--r--net/mptcp/protocol.c4099
1 files changed, 4099 insertions, 0 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
new file mode 100644
index 000000000..76539d100
--- /dev/null
+++ b/net/mptcp/protocol.c
@@ -0,0 +1,4099 @@
+// 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 <net/xfrm.h>
+#include <asm/ioctls.h>
+#include "protocol.h"
+#include "mib.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/mptcp.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;
+ u8 has_rxtstamp:1;
+};
+
+#define MPTCP_SKB_CB(__skb) ((struct mptcp_skb_cb *)&((__skb)->cb[0]))
+
+enum {
+ MPTCP_CMSG_TS = BIT(0),
+ MPTCP_CMSG_INQ = BIT(1),
+};
+
+static struct percpu_counter mptcp_sockets_allocated ____cacheline_aligned_in_smp;
+
+static void __mptcp_destroy_sock(struct sock *sk);
+static void mptcp_check_send_data_fin(struct sock *sk);
+
+DEFINE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
+static struct net_device mptcp_napi_dev;
+
+/* 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.
+ */
+struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk)
+{
+ if (!msk->subflow || READ_ONCE(msk->can_ack))
+ return NULL;
+
+ return msk->subflow;
+}
+
+/* Returns end sequence number of the receiver's advertised window */
+static u64 mptcp_wnd_end(const struct mptcp_sock *msk)
+{
+ return READ_ONCE(msk->wnd_end);
+}
+
+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 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, sk->sk_family, &ssock);
+ if (err)
+ return err;
+
+ WRITE_ONCE(msk->first, ssock->sk);
+ WRITE_ONCE(msk->subflow, ssock);
+ subflow = mptcp_subflow_ctx(ssock->sk);
+ list_add(&subflow->node, &msk->conn_list);
+ sock_hold(ssock->sk);
+ subflow->request_mptcp = 1;
+
+ /* This is the first subflow, always with id 0 */
+ subflow->local_id_valid = 1;
+ mptcp_sock_graft(msk->first, sk->sk_socket);
+
+ return 0;
+}
+
+static void mptcp_drop(struct sock *sk, struct sk_buff *skb)
+{
+ sk_drops_add(sk, skb);
+ __kfree_skb(skb);
+}
+
+static void mptcp_rmem_fwd_alloc_add(struct sock *sk, int size)
+{
+ WRITE_ONCE(mptcp_sk(sk)->rmem_fwd_alloc,
+ mptcp_sk(sk)->rmem_fwd_alloc + size);
+}
+
+static void mptcp_rmem_charge(struct sock *sk, int size)
+{
+ mptcp_rmem_fwd_alloc_add(sk, -size);
+}
+
+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;
+
+ /* note the fwd memory can reach a negative value after accounting
+ * for the delta, but the later skb free will restore a non
+ * negative one
+ */
+ atomic_add(delta, &sk->sk_rmem_alloc);
+ mptcp_rmem_charge(sk, delta);
+ kfree_skb_partial(from, fragstolen);
+
+ 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);
+}
+
+static void __mptcp_rmem_reclaim(struct sock *sk, int amount)
+{
+ amount >>= PAGE_SHIFT;
+ mptcp_rmem_charge(sk, amount << PAGE_SHIFT);
+ __sk_mem_reduce_allocated(sk, amount);
+}
+
+static void mptcp_rmem_uncharge(struct sock *sk, int size)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ int reclaimable;
+
+ mptcp_rmem_fwd_alloc_add(sk, size);
+ reclaimable = msk->rmem_fwd_alloc - sk_unused_reserved_mem(sk);
+
+ /* see sk_mem_uncharge() for the rationale behind the following schema */
+ if (unlikely(reclaimable >= PAGE_SIZE))
+ __mptcp_rmem_reclaim(sk, reclaimable);
+}
+
+static void mptcp_rfree(struct sk_buff *skb)
+{
+ unsigned int len = skb->truesize;
+ struct sock *sk = skb->sk;
+
+ atomic_sub(len, &sk->sk_rmem_alloc);
+ mptcp_rmem_uncharge(sk, len);
+}
+
+static void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk)
+{
+ skb_orphan(skb);
+ skb->sk = sk;
+ skb->destructor = mptcp_rfree;
+ atomic_add(skb->truesize, &sk->sk_rmem_alloc);
+ mptcp_rmem_charge(sk, skb->truesize);
+}
+
+/* "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;
+
+ seq = MPTCP_SKB_CB(skb)->map_seq;
+ end_seq = MPTCP_SKB_CB(skb)->end_seq;
+ max_seq = atomic64_read(&msk->rcv_wnd_sent);
+
+ pr_debug("msk=%p seq=%llx limit=%llx empty=%d", msk, seq, max_seq,
+ RB_EMPTY_ROOT(&msk->out_of_order_queue));
+ if (after64(end_seq, max_seq)) {
+ /* out of window */
+ mptcp_drop(sk, skb);
+ pr_debug("oow by %lld, rcv_wnd_sent %llu\n",
+ (unsigned long long)end_seq - (unsigned long)max_seq,
+ (unsigned long long)atomic64_read(&msk->rcv_wnd_sent));
+ 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);
+ mptcp_set_owner_r(skb, sk);
+}
+
+static bool mptcp_rmem_schedule(struct sock *sk, struct sock *ssk, int size)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ int amt, amount;
+
+ if (size <= msk->rmem_fwd_alloc)
+ return true;
+
+ size -= msk->rmem_fwd_alloc;
+ amt = sk_mem_pages(size);
+ amount = amt << PAGE_SHIFT;
+ if (!__sk_mem_raise_allocated(sk, size, amt, SK_MEM_RECV))
+ return false;
+
+ mptcp_rmem_fwd_alloc_add(sk, amount);
+ return true;
+}
+
+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;
+ bool has_rxtstamp;
+
+ __skb_unlink(skb, &ssk->sk_receive_queue);
+
+ skb_ext_reset(skb);
+ skb_orphan(skb);
+
+ /* try to fetch required memory from subflow */
+ if (!mptcp_rmem_schedule(sk, ssk, skb->truesize))
+ goto drop;
+
+ has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp;
+
+ /* 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;
+ MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp;
+
+ 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;
+
+ mptcp_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_rtx_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_close_wake_up(struct sock *sk)
+{
+ if (sock_flag(sk, SOCK_DEAD))
+ return;
+
+ 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_pending_data_fin_ack(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ return ((1 << sk->sk_state) &
+ (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) &&
+ msk->write_seq == READ_ONCE(msk->snd_una);
+}
+
+static void mptcp_check_data_fin_ack(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ /* Look for an acknowledged DATA_FIN */
+ if (mptcp_pending_data_fin_ack(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);
+ break;
+ case TCP_CLOSING:
+ case TCP_LAST_ACK:
+ inet_sk_state_store(sk, TCP_CLOSE);
+ break;
+ }
+
+ mptcp_close_wake_up(sk);
+ }
+}
+
+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_datafin_timeout(const struct sock *sk)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ u32 retransmits;
+
+ retransmits = min_t(u32, icsk->icsk_retransmits,
+ ilog2(TCP_RTO_MAX / TCP_RTO_MIN));
+
+ mptcp_sk(sk)->timer_ival = TCP_RTO_MIN << retransmits;
+}
+
+static void __mptcp_set_timeout(struct sock *sk, long tout)
+{
+ mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
+}
+
+static long mptcp_timeout_from_subflow(const struct mptcp_subflow_context *subflow)
+{
+ const struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ return inet_csk(ssk)->icsk_pending && !subflow->stale_count ?
+ inet_csk(ssk)->icsk_timeout - jiffies : 0;
+}
+
+static void mptcp_set_timeout(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow;
+ long tout = 0;
+
+ mptcp_for_each_subflow(mptcp_sk(sk), subflow)
+ tout = max(tout, mptcp_timeout_from_subflow(subflow));
+ __mptcp_set_timeout(sk, tout);
+}
+
+static inline bool tcp_can_send_ack(const struct sock *ssk)
+{
+ return !((1 << inet_sk_state_load(ssk)) &
+ (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE | TCPF_LISTEN));
+}
+
+void __mptcp_subflow_send_ack(struct sock *ssk)
+{
+ if (tcp_can_send_ack(ssk))
+ tcp_send_ack(ssk);
+}
+
+static void mptcp_subflow_send_ack(struct sock *ssk)
+{
+ bool slow;
+
+ slow = lock_sock_fast(ssk);
+ __mptcp_subflow_send_ack(ssk);
+ unlock_sock_fast(ssk, slow);
+}
+
+static void mptcp_send_ack(struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow;
+
+ mptcp_for_each_subflow(msk, subflow)
+ mptcp_subflow_send_ack(mptcp_subflow_tcp_sock(subflow));
+}
+
+static void mptcp_subflow_cleanup_rbuf(struct sock *ssk)
+{
+ bool slow;
+
+ slow = lock_sock_fast(ssk);
+ if (tcp_can_send_ack(ssk))
+ tcp_cleanup_rbuf(ssk, 1);
+ unlock_sock_fast(ssk, slow);
+}
+
+static bool mptcp_subflow_could_cleanup(const struct sock *ssk, bool rx_empty)
+{
+ const struct inet_connection_sock *icsk = inet_csk(ssk);
+ u8 ack_pending = READ_ONCE(icsk->icsk_ack.pending);
+ const struct tcp_sock *tp = tcp_sk(ssk);
+
+ return (ack_pending & ICSK_ACK_SCHED) &&
+ ((READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->rcv_wup) >
+ READ_ONCE(icsk->icsk_ack.rcv_mss)) ||
+ (rx_empty && ack_pending &
+ (ICSK_ACK_PUSHED2 | ICSK_ACK_PUSHED)));
+}
+
+static void mptcp_cleanup_rbuf(struct mptcp_sock *msk)
+{
+ int old_space = READ_ONCE(msk->old_wspace);
+ struct mptcp_subflow_context *subflow;
+ struct sock *sk = (struct sock *)msk;
+ int space = __mptcp_space(sk);
+ bool cleanup, rx_empty;
+
+ cleanup = (space > 0) && (space >= (old_space << 1));
+ rx_empty = !__mptcp_rmem(sk);
+
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ if (cleanup || mptcp_subflow_could_cleanup(ssk, rx_empty))
+ mptcp_subflow_cleanup_rbuf(ssk);
+ }
+}
+
+static bool mptcp_check_data_fin(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ u64 rcv_data_fin_seq;
+ bool ret = false;
+
+ /* 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)) {
+ WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1);
+ WRITE_ONCE(msk->rcv_data_fin, 0);
+
+ WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | RCV_SHUTDOWN);
+ smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
+
+ 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);
+ break;
+ default:
+ /* Other states not expected */
+ WARN_ON_ONCE(1);
+ break;
+ }
+
+ ret = true;
+ if (!__mptcp_check_fallback(msk))
+ mptcp_send_ack(msk);
+ mptcp_close_wake_up(sk);
+ }
+ return ret;
+}
+
+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;
+ bool done = false;
+ int sk_rbuf;
+
+ sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
+
+ if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
+ int ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
+
+ if (unlikely(ssk_rbuf > sk_rbuf)) {
+ WRITE_ONCE(sk->sk_rcvbuf, ssk_rbuf);
+ sk_rbuf = ssk_rbuf;
+ }
+ }
+
+ pr_debug("msk=%p ssk=%p", msk, ssk);
+ tp = tcp_sk(ssk);
+ 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) {
+ /* With racing move_skbs_to_msk() and __mptcp_move_skbs(),
+ * a different CPU can have already processed the pending
+ * data, stop here or we can enter an infinite loop
+ */
+ if (!moved)
+ done = true;
+ break;
+ }
+
+ if (__mptcp_check_fallback(msk)) {
+ /* Under fallback skbs have no MPTCP extension and TCP could
+ * collapse them between the dummy map creation and the
+ * current dequeue. Be sure to adjust the map 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) > sk_rbuf) {
+ done = true;
+ break;
+ }
+ } while (more_data_avail);
+
+ *bytes += moved;
+ 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;
+ MPTCP_SKB_CB(skb)->map_seq += delta;
+ __skb_queue_tail(&sk->sk_receive_queue, skb);
+ }
+ msk->ack_seq = end_seq;
+ moved = true;
+ }
+ return moved;
+}
+
+static bool __mptcp_subflow_error_report(struct sock *sk, struct sock *ssk)
+{
+ int err = sock_error(ssk);
+ int ssk_state;
+
+ if (!err)
+ return false;
+
+ /* only propagate errors on fallen-back sockets or
+ * on MPC connect
+ */
+ if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(mptcp_sk(sk)))
+ return false;
+
+ /* We need to propagate only transition to CLOSE state.
+ * Orphaned socket will see such state change via
+ * subflow_sched_work_if_closed() and that path will properly
+ * destroy the msk as needed.
+ */
+ ssk_state = inet_sk_state_load(ssk);
+ if (ssk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DEAD))
+ inet_sk_state_store(sk, ssk_state);
+ WRITE_ONCE(sk->sk_err, -err);
+
+ /* This barrier is coupled with smp_rmb() in mptcp_poll() */
+ smp_wmb();
+ sk_error_report(sk);
+ return true;
+}
+
+void __mptcp_error_report(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ mptcp_for_each_subflow(msk, subflow)
+ if (__mptcp_subflow_error_report(sk, mptcp_subflow_tcp_sock(subflow)))
+ break;
+}
+
+/* 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;
+
+ __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
+ __mptcp_ofo_queue(msk);
+ if (unlikely(ssk->sk_err)) {
+ if (!sock_owned_by_user(sk))
+ __mptcp_error_report(sk);
+ else
+ __set_bit(MPTCP_ERROR_REPORT, &msk->cb_flags);
+ }
+
+ /* 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))
+ mptcp_schedule_work(sk);
+ 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);
+ int sk_rbuf, ssk_rbuf;
+
+ /* The peer can send data while we are shutting down this
+ * subflow at msk destruction time, but we must avoid enqueuing
+ * more data to the msk receive queue
+ */
+ if (unlikely(subflow->disposable))
+ return;
+
+ ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
+ sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
+ if (unlikely(ssk_rbuf > sk_rbuf))
+ sk_rbuf = ssk_rbuf;
+
+ /* over limit? can't append more skbs to msk, Also, no need to wake-up*/
+ if (__mptcp_rmem(sk) > sk_rbuf) {
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED);
+ return;
+ }
+
+ /* Wake-up the reader only for in-sequence data */
+ mptcp_data_lock(sk);
+ if (move_skbs_to_msk(msk, ssk))
+ sk->sk_data_ready(sk);
+
+ mptcp_data_unlock(sk);
+}
+
+static void mptcp_subflow_joined(struct mptcp_sock *msk, struct sock *ssk)
+{
+ mptcp_subflow_ctx(ssk)->map_seq = READ_ONCE(msk->ack_seq);
+ WRITE_ONCE(msk->allow_infinite_fallback, false);
+ mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC);
+}
+
+static bool __mptcp_finish_join(struct mptcp_sock *msk, struct sock *ssk)
+{
+ struct sock *sk = (struct sock *)msk;
+
+ if (sk->sk_state != TCP_ESTABLISHED)
+ return false;
+
+ /* attach to msk socket only after we are sure we will deal with it
+ * at close time
+ */
+ if (sk->sk_socket && !ssk->sk_socket)
+ mptcp_sock_graft(ssk, sk->sk_socket);
+
+ mptcp_sockopt_sync_locked(msk, ssk);
+ mptcp_subflow_joined(msk, ssk);
+ mptcp_stop_tout_timer(sk);
+ return true;
+}
+
+static void __mptcp_flush_join_list(struct sock *sk, struct list_head *join_list)
+{
+ struct mptcp_subflow_context *tmp, *subflow;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ list_for_each_entry_safe(subflow, tmp, join_list, node) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+ bool slow = lock_sock_fast(ssk);
+
+ list_move_tail(&subflow->node, &msk->conn_list);
+ if (!__mptcp_finish_join(msk, ssk))
+ mptcp_subflow_reset(ssk);
+ unlock_sock_fast(ssk, slow);
+ }
+}
+
+static bool mptcp_rtx_timer_pending(struct sock *sk)
+{
+ return timer_pending(&inet_csk(sk)->icsk_retransmit_timer);
+}
+
+static void mptcp_reset_rtx_timer(struct sock *sk)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ unsigned long tout;
+
+ /* prevent rescheduling on close */
+ if (unlikely(inet_sk_state_load(sk) == TCP_CLOSE))
+ return;
+
+ tout = mptcp_sk(sk)->timer_ival;
+ sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout);
+}
+
+bool mptcp_schedule_work(struct sock *sk)
+{
+ if (inet_sk_state_load(sk) != TCP_CLOSE &&
+ schedule_work(&mptcp_sk(sk)->work)) {
+ /* each subflow already holds a reference to the sk, and the
+ * workqueue is invoked by a subflow, so sk can't go away here.
+ */
+ sock_hold(sk);
+ return true;
+ }
+ return false;
+}
+
+void mptcp_subflow_eof(struct sock *sk)
+{
+ if (!test_and_set_bit(MPTCP_WORK_EOF, &mptcp_sk(sk)->flags))
+ mptcp_schedule_work(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)
+ return;
+
+ if (!(sk->sk_shutdown & RCV_SHUTDOWN)) {
+ /* hopefully temporary hack: propagate shutdown status
+ * to msk, when all subflows agree on it
+ */
+ WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | RCV_SHUTDOWN);
+
+ smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
+ sk->sk_data_ready(sk);
+ }
+
+ 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);
+ break;
+ default:
+ return;
+ }
+ mptcp_close_wake_up(sk);
+}
+
+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 (READ_ONCE(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 and this
+ * mapping has not been xmitted yet
+ */
+ return mpext && mpext->data_seq + mpext->data_len == write_seq &&
+ !mpext->frozen;
+}
+
+/* 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->size - pfrag->offset > 0 &&
+ 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 void __mptcp_clean_una(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct mptcp_data_frag *dtmp, *dfrag;
+ u64 snd_una;
+
+ /* on fallback we just need to ignore snd_una, as this is really
+ * plain TCP
+ */
+ if (__mptcp_check_fallback(msk))
+ msk->snd_una = READ_ONCE(msk->snd_nxt);
+
+ snd_una = 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;
+
+ if (unlikely(dfrag == msk->first_pending)) {
+ /* in recovery mode can see ack after the current snd head */
+ if (WARN_ON_ONCE(!msk->recovery))
+ break;
+
+ WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
+ }
+
+ dfrag_clear(sk, dfrag);
+ }
+
+ dfrag = mptcp_rtx_head(sk);
+ if (dfrag && after64(snd_una, dfrag->data_seq)) {
+ u64 delta = snd_una - dfrag->data_seq;
+
+ /* prevent wrap around in recovery mode */
+ if (unlikely(delta > dfrag->already_sent)) {
+ if (WARN_ON_ONCE(!msk->recovery))
+ goto out;
+ if (WARN_ON_ONCE(delta > dfrag->data_len))
+ goto out;
+ dfrag->already_sent += delta - dfrag->already_sent;
+ }
+
+ dfrag->data_seq += delta;
+ dfrag->offset += delta;
+ dfrag->data_len -= delta;
+ dfrag->already_sent -= delta;
+
+ dfrag_uncharge(sk, delta);
+ }
+
+ /* all retransmitted data acked, recovery completed */
+ if (unlikely(msk->recovery) && after64(msk->snd_una, msk->recovery_snd_nxt))
+ msk->recovery = false;
+
+out:
+ if (snd_una == READ_ONCE(msk->snd_nxt) &&
+ snd_una == READ_ONCE(msk->write_seq)) {
+ if (mptcp_rtx_timer_pending(sk) && !mptcp_data_fin_enabled(msk))
+ mptcp_stop_rtx_timer(sk);
+ } else {
+ mptcp_reset_rtx_timer(sk);
+ }
+}
+
+static void __mptcp_clean_una_wakeup(struct sock *sk)
+{
+ lockdep_assert_held_once(&sk->sk_lock.slock);
+
+ __mptcp_clean_una(sk);
+ mptcp_write_space(sk);
+}
+
+static void mptcp_clean_una_wakeup(struct sock *sk)
+{
+ mptcp_data_lock(sk);
+ __mptcp_clean_una_wakeup(sk);
+ mptcp_data_unlock(sk);
+}
+
+static void mptcp_enter_memory_pressure(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ bool first = true;
+
+ sk_stream_moderate_sndbuf(sk);
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ if (first)
+ tcp_enter_memory_pressure(ssk);
+ sk_stream_moderate_sndbuf(ssk);
+ first = false;
+ }
+}
+
+/* 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;
+
+ mptcp_enter_memory_pressure(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->already_sent = 0;
+ dfrag->page = pfrag->page;
+
+ return dfrag;
+}
+
+struct mptcp_sendmsg_info {
+ int mss_now;
+ int size_goal;
+ u16 limit;
+ u16 sent;
+ unsigned int flags;
+ bool data_lock_held;
+};
+
+static int mptcp_check_allowed_size(const struct mptcp_sock *msk, struct sock *ssk,
+ u64 data_seq, int avail_size)
+{
+ u64 window_end = mptcp_wnd_end(msk);
+ u64 mptcp_snd_wnd;
+
+ if (__mptcp_check_fallback(msk))
+ return avail_size;
+
+ mptcp_snd_wnd = window_end - data_seq;
+ avail_size = min_t(unsigned int, mptcp_snd_wnd, avail_size);
+
+ if (unlikely(tcp_sk(ssk)->snd_wnd < mptcp_snd_wnd)) {
+ tcp_sk(ssk)->snd_wnd = min_t(u64, U32_MAX, mptcp_snd_wnd);
+ MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_SNDWNDSHARED);
+ }
+
+ return avail_size;
+}
+
+static bool __mptcp_add_ext(struct sk_buff *skb, gfp_t gfp)
+{
+ struct skb_ext *mpext = __skb_ext_alloc(gfp);
+
+ if (!mpext)
+ return false;
+ __skb_ext_set(skb, SKB_EXT_MPTCP, mpext);
+ return true;
+}
+
+static struct sk_buff *__mptcp_do_alloc_tx_skb(struct sock *sk, gfp_t gfp)
+{
+ struct sk_buff *skb;
+
+ skb = alloc_skb_fclone(MAX_TCP_HEADER, gfp);
+ if (likely(skb)) {
+ if (likely(__mptcp_add_ext(skb, gfp))) {
+ skb_reserve(skb, MAX_TCP_HEADER);
+ skb->ip_summed = CHECKSUM_PARTIAL;
+ INIT_LIST_HEAD(&skb->tcp_tsorted_anchor);
+ return skb;
+ }
+ __kfree_skb(skb);
+ } else {
+ mptcp_enter_memory_pressure(sk);
+ }
+ return NULL;
+}
+
+static struct sk_buff *__mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, gfp_t gfp)
+{
+ struct sk_buff *skb;
+
+ skb = __mptcp_do_alloc_tx_skb(sk, gfp);
+ if (!skb)
+ return NULL;
+
+ if (likely(sk_wmem_schedule(ssk, skb->truesize))) {
+ tcp_skb_entail(ssk, skb);
+ return skb;
+ }
+ tcp_skb_tsorted_anchor_cleanup(skb);
+ kfree_skb(skb);
+ return NULL;
+}
+
+static struct sk_buff *mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, bool data_lock_held)
+{
+ gfp_t gfp = data_lock_held ? GFP_ATOMIC : sk->sk_allocation;
+
+ return __mptcp_alloc_tx_skb(sk, ssk, gfp);
+}
+
+/* note: this always recompute the csum on the whole skb, even
+ * if we just appended a single frag. More status info needed
+ */
+static void mptcp_update_data_checksum(struct sk_buff *skb, int added)
+{
+ struct mptcp_ext *mpext = mptcp_get_ext(skb);
+ __wsum csum = ~csum_unfold(mpext->csum);
+ int offset = skb->len - added;
+
+ mpext->csum = csum_fold(csum_block_add(csum, skb_checksum(skb, offset, added, 0), offset));
+}
+
+static void mptcp_update_infinite_map(struct mptcp_sock *msk,
+ struct sock *ssk,
+ struct mptcp_ext *mpext)
+{
+ if (!mpext)
+ return;
+
+ mpext->infinite_map = 1;
+ mpext->data_len = 0;
+
+ MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPTX);
+ mptcp_subflow_ctx(ssk)->send_infinite_map = 0;
+ pr_fallback(msk);
+ mptcp_do_fallback(ssk);
+}
+
+#define MPTCP_MAX_GSO_SIZE (GSO_LEGACY_MAX_SIZE - (MAX_TCP_HEADER + 1))
+
+static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
+ struct mptcp_data_frag *dfrag,
+ struct mptcp_sendmsg_info *info)
+{
+ u64 data_seq = dfrag->data_seq + info->sent;
+ int offset = dfrag->offset + info->sent;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ bool zero_window_probe = false;
+ struct mptcp_ext *mpext = NULL;
+ bool can_coalesce = false;
+ bool reuse_skb = true;
+ struct sk_buff *skb;
+ size_t copy;
+ int i;
+
+ pr_debug("msk=%p ssk=%p sending dfrag at seq=%llu len=%u already sent=%u",
+ msk, ssk, dfrag->data_seq, dfrag->data_len, info->sent);
+
+ if (WARN_ON_ONCE(info->sent > info->limit ||
+ info->limit > dfrag->data_len))
+ return 0;
+
+ if (unlikely(!__tcp_can_send(ssk)))
+ return -EAGAIN;
+
+ /* compute send limit */
+ if (unlikely(ssk->sk_gso_max_size > MPTCP_MAX_GSO_SIZE))
+ ssk->sk_gso_max_size = MPTCP_MAX_GSO_SIZE;
+ info->mss_now = tcp_send_mss(ssk, &info->size_goal, info->flags);
+ copy = info->size_goal;
+
+ skb = tcp_write_queue_tail(ssk);
+ if (skb && copy > skb->len) {
+ /* 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
+ */
+ mpext = skb_ext_find(skb, SKB_EXT_MPTCP);
+ if (!mptcp_skb_can_collapse_to(data_seq, skb, mpext)) {
+ TCP_SKB_CB(skb)->eor = 1;
+ goto alloc_skb;
+ }
+
+ i = skb_shinfo(skb)->nr_frags;
+ can_coalesce = skb_can_coalesce(skb, i, dfrag->page, offset);
+ if (!can_coalesce && i >= READ_ONCE(sysctl_max_skb_frags)) {
+ tcp_mark_push(tcp_sk(ssk), skb);
+ goto alloc_skb;
+ }
+
+ copy -= skb->len;
+ } else {
+alloc_skb:
+ skb = mptcp_alloc_tx_skb(sk, ssk, info->data_lock_held);
+ if (!skb)
+ return -ENOMEM;
+
+ i = skb_shinfo(skb)->nr_frags;
+ reuse_skb = false;
+ mpext = skb_ext_find(skb, SKB_EXT_MPTCP);
+ }
+
+ /* Zero window and all data acked? Probe. */
+ copy = mptcp_check_allowed_size(msk, ssk, data_seq, copy);
+ if (copy == 0) {
+ u64 snd_una = READ_ONCE(msk->snd_una);
+
+ if (snd_una != msk->snd_nxt || tcp_write_queue_tail(ssk)) {
+ tcp_remove_empty_skb(ssk);
+ return 0;
+ }
+
+ zero_window_probe = true;
+ data_seq = snd_una - 1;
+ copy = 1;
+ }
+
+ copy = min_t(size_t, copy, info->limit - info->sent);
+ if (!sk_wmem_schedule(ssk, copy)) {
+ tcp_remove_empty_skb(ssk);
+ return -ENOMEM;
+ }
+
+ if (can_coalesce) {
+ skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
+ } else {
+ get_page(dfrag->page);
+ skb_fill_page_desc(skb, i, dfrag->page, offset, copy);
+ }
+
+ skb->len += copy;
+ skb->data_len += copy;
+ skb->truesize += copy;
+ sk_wmem_queued_add(ssk, copy);
+ sk_mem_charge(ssk, copy);
+ WRITE_ONCE(tcp_sk(ssk)->write_seq, tcp_sk(ssk)->write_seq + copy);
+ TCP_SKB_CB(skb)->end_seq += copy;
+ tcp_skb_pcount_set(skb, 0);
+
+ /* on skb reuse we just need to update the DSS len */
+ if (reuse_skb) {
+ TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
+ mpext->data_len += copy;
+ goto out;
+ }
+
+ memset(mpext, 0, sizeof(*mpext));
+ mpext->data_seq = data_seq;
+ mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq;
+ mpext->data_len = copy;
+ 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);
+
+ if (zero_window_probe) {
+ mptcp_subflow_ctx(ssk)->rel_write_seq += copy;
+ mpext->frozen = 1;
+ if (READ_ONCE(msk->csum_enabled))
+ mptcp_update_data_checksum(skb, copy);
+ tcp_push_pending_frames(ssk);
+ return 0;
+ }
+out:
+ if (READ_ONCE(msk->csum_enabled))
+ mptcp_update_data_checksum(skb, copy);
+ if (mptcp_subflow_ctx(ssk)->send_infinite_map)
+ mptcp_update_infinite_map(msk, ssk, mpext);
+ trace_mptcp_sendmsg_frag(mpext);
+ mptcp_subflow_ctx(ssk)->rel_write_seq += copy;
+ return copy;
+}
+
+#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 linger_time;
+};
+
+void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow)
+{
+ if (!subflow->stale)
+ return;
+
+ subflow->stale = 0;
+ MPTCP_INC_STATS(sock_net(mptcp_subflow_tcp_sock(subflow)), MPTCP_MIB_SUBFLOWRECOVER);
+}
+
+bool mptcp_subflow_active(struct mptcp_subflow_context *subflow)
+{
+ if (unlikely(subflow->stale)) {
+ u32 rcv_tstamp = READ_ONCE(tcp_sk(mptcp_subflow_tcp_sock(subflow))->rcv_tstamp);
+
+ if (subflow->stale_rcv_tstamp == rcv_tstamp)
+ return false;
+
+ mptcp_subflow_set_active(subflow);
+ }
+ return __mptcp_subflow_active(subflow);
+}
+
+#define SSK_MODE_ACTIVE 0
+#define SSK_MODE_BACKUP 1
+#define SSK_MODE_MAX 2
+
+/* implement the mptcp packet scheduler;
+ * returns the subflow that will transmit the next DSS
+ * additionally updates the rtx timeout
+ */
+static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk)
+{
+ struct subflow_send_info send_info[SSK_MODE_MAX];
+ struct mptcp_subflow_context *subflow;
+ struct sock *sk = (struct sock *)msk;
+ u32 pace, burst, wmem;
+ int i, nr_active = 0;
+ struct sock *ssk;
+ u64 linger_time;
+ long tout = 0;
+
+ sock_owned_by_me(sk);
+
+ if (__mptcp_check_fallback(msk)) {
+ if (!msk->first)
+ return NULL;
+ return __tcp_can_send(msk->first) &&
+ 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_set_timeout(sk);
+ return msk->last_snd;
+ }
+
+ /* pick the subflow with the lower wmem/wspace ratio */
+ for (i = 0; i < SSK_MODE_MAX; ++i) {
+ send_info[i].ssk = NULL;
+ send_info[i].linger_time = -1;
+ }
+
+ mptcp_for_each_subflow(msk, subflow) {
+ trace_mptcp_subflow_get_send(subflow);
+ ssk = mptcp_subflow_tcp_sock(subflow);
+ if (!mptcp_subflow_active(subflow))
+ continue;
+
+ tout = max(tout, mptcp_timeout_from_subflow(subflow));
+ nr_active += !subflow->backup;
+ pace = subflow->avg_pacing_rate;
+ if (unlikely(!pace)) {
+ /* init pacing rate from socket */
+ subflow->avg_pacing_rate = READ_ONCE(ssk->sk_pacing_rate);
+ pace = subflow->avg_pacing_rate;
+ if (!pace)
+ continue;
+ }
+
+ linger_time = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32, pace);
+ if (linger_time < send_info[subflow->backup].linger_time) {
+ send_info[subflow->backup].ssk = ssk;
+ send_info[subflow->backup].linger_time = linger_time;
+ }
+ }
+ __mptcp_set_timeout(sk, tout);
+
+ /* pick the best backup if no other subflow is active */
+ if (!nr_active)
+ send_info[SSK_MODE_ACTIVE].ssk = send_info[SSK_MODE_BACKUP].ssk;
+
+ /* According to the blest algorithm, to avoid HoL blocking for the
+ * faster flow, we need to:
+ * - estimate the faster flow linger time
+ * - use the above to estimate the amount of byte transferred
+ * by the faster flow
+ * - check that the amount of queued data is greter than the above,
+ * otherwise do not use the picked, slower, subflow
+ * We select the subflow with the shorter estimated time to flush
+ * the queued mem, which basically ensure the above. We just need
+ * to check that subflow has a non empty cwin.
+ */
+ ssk = send_info[SSK_MODE_ACTIVE].ssk;
+ if (!ssk || !sk_stream_memory_free(ssk))
+ return NULL;
+
+ burst = min_t(int, MPTCP_SEND_BURST_SIZE, mptcp_wnd_end(msk) - msk->snd_nxt);
+ wmem = READ_ONCE(ssk->sk_wmem_queued);
+ if (!burst) {
+ msk->last_snd = NULL;
+ return ssk;
+ }
+
+ subflow = mptcp_subflow_ctx(ssk);
+ subflow->avg_pacing_rate = div_u64((u64)subflow->avg_pacing_rate * wmem +
+ READ_ONCE(ssk->sk_pacing_rate) * burst,
+ burst + wmem);
+ msk->last_snd = ssk;
+ msk->snd_burst = burst;
+ return ssk;
+}
+
+static void mptcp_push_release(struct sock *ssk, struct mptcp_sendmsg_info *info)
+{
+ tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal);
+ release_sock(ssk);
+}
+
+static void mptcp_update_post_push(struct mptcp_sock *msk,
+ struct mptcp_data_frag *dfrag,
+ u32 sent)
+{
+ u64 snd_nxt_new = dfrag->data_seq;
+
+ dfrag->already_sent += sent;
+
+ msk->snd_burst -= sent;
+
+ snd_nxt_new += dfrag->already_sent;
+
+ /* snd_nxt_new can be smaller than snd_nxt in case mptcp
+ * is recovering after a failover. In that event, this re-sends
+ * old segments.
+ *
+ * Thus compute snd_nxt_new candidate based on
+ * the dfrag->data_seq that was sent and the data
+ * that has been handed to the subflow for transmission
+ * and skip update in case it was old dfrag.
+ */
+ if (likely(after64(snd_nxt_new, msk->snd_nxt)))
+ msk->snd_nxt = snd_nxt_new;
+}
+
+void mptcp_check_and_set_pending(struct sock *sk)
+{
+ if (mptcp_send_head(sk))
+ mptcp_sk(sk)->push_pending |= BIT(MPTCP_PUSH_PENDING);
+}
+
+void __mptcp_push_pending(struct sock *sk, unsigned int flags)
+{
+ struct sock *prev_ssk = NULL, *ssk = NULL;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct mptcp_sendmsg_info info = {
+ .flags = flags,
+ };
+ bool do_check_data_fin = false;
+ struct mptcp_data_frag *dfrag;
+ int len;
+
+ while ((dfrag = mptcp_send_head(sk))) {
+ info.sent = dfrag->already_sent;
+ info.limit = dfrag->data_len;
+ len = dfrag->data_len - dfrag->already_sent;
+ while (len > 0) {
+ int ret = 0;
+
+ prev_ssk = ssk;
+ ssk = mptcp_subflow_get_send(msk);
+
+ /* First check. If the ssk has changed since
+ * the last round, release prev_ssk
+ */
+ if (ssk != prev_ssk && prev_ssk)
+ mptcp_push_release(prev_ssk, &info);
+ if (!ssk)
+ goto out;
+
+ /* Need to lock the new subflow only if different
+ * from the previous one, otherwise we are still
+ * helding the relevant lock
+ */
+ if (ssk != prev_ssk)
+ lock_sock(ssk);
+
+ ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
+ if (ret <= 0) {
+ if (ret == -EAGAIN)
+ continue;
+ mptcp_push_release(ssk, &info);
+ goto out;
+ }
+
+ do_check_data_fin = true;
+ info.sent += ret;
+ len -= ret;
+
+ mptcp_update_post_push(msk, dfrag, ret);
+ }
+ WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
+ }
+
+ /* at this point we held the socket lock for the last subflow we used */
+ if (ssk)
+ mptcp_push_release(ssk, &info);
+
+out:
+ /* ensure the rtx timer is running */
+ if (!mptcp_rtx_timer_pending(sk))
+ mptcp_reset_rtx_timer(sk);
+ if (do_check_data_fin)
+ mptcp_check_send_data_fin(sk);
+}
+
+static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct mptcp_sendmsg_info info = {
+ .data_lock_held = true,
+ };
+ struct mptcp_data_frag *dfrag;
+ struct sock *xmit_ssk;
+ int len, copied = 0;
+ bool first = true;
+
+ info.flags = 0;
+ while ((dfrag = mptcp_send_head(sk))) {
+ info.sent = dfrag->already_sent;
+ info.limit = dfrag->data_len;
+ len = dfrag->data_len - dfrag->already_sent;
+ while (len > 0) {
+ int ret = 0;
+
+ /* the caller already invoked the packet scheduler,
+ * check for a different subflow usage only after
+ * spooling the first chunk of data
+ */
+ xmit_ssk = first ? ssk : mptcp_subflow_get_send(mptcp_sk(sk));
+ if (!xmit_ssk)
+ goto out;
+ if (xmit_ssk != ssk) {
+ mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk),
+ MPTCP_DELEGATE_SEND);
+ goto out;
+ }
+
+ ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
+ if (ret <= 0)
+ goto out;
+
+ info.sent += ret;
+ copied += ret;
+ len -= ret;
+ first = false;
+
+ mptcp_update_post_push(msk, dfrag, ret);
+ }
+ WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
+ }
+
+out:
+ /* __mptcp_alloc_tx_skb could have released some wmem and we are
+ * not going to flush it via release_sock()
+ */
+ if (copied) {
+ tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
+ info.size_goal);
+ if (!mptcp_rtx_timer_pending(sk))
+ mptcp_reset_rtx_timer(sk);
+
+ if (msk->snd_data_fin_enable &&
+ msk->snd_nxt + 1 == msk->write_seq)
+ mptcp_schedule_work(sk);
+ }
+}
+
+static void mptcp_set_nospace(struct sock *sk)
+{
+ /* enable autotune */
+ set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
+
+ /* will be cleared on avail space */
+ set_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags);
+}
+
+static int mptcp_disconnect(struct sock *sk, int flags);
+
+static int mptcp_sendmsg_fastopen(struct sock *sk, struct sock *ssk, struct msghdr *msg,
+ size_t len, int *copied_syn)
+{
+ unsigned int saved_flags = msg->msg_flags;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ int ret;
+
+ lock_sock(ssk);
+ msg->msg_flags |= MSG_DONTWAIT;
+ msk->fastopening = 1;
+ ret = tcp_sendmsg_fastopen(ssk, msg, copied_syn, len, NULL);
+ msk->fastopening = 0;
+ msg->msg_flags = saved_flags;
+ release_sock(ssk);
+
+ /* do the blocking bits of inet_stream_connect outside the ssk socket lock */
+ if (ret == -EINPROGRESS && !(msg->msg_flags & MSG_DONTWAIT)) {
+ ret = __inet_stream_connect(sk->sk_socket, msg->msg_name,
+ msg->msg_namelen, msg->msg_flags, 1);
+
+ /* Keep the same behaviour of plain TCP: zero the copied bytes in
+ * case of any error, except timeout or signal
+ */
+ if (ret && ret != -EINPROGRESS && ret != -ERESTARTSYS && ret != -EINTR)
+ *copied_syn = 0;
+ } else if (ret && ret != -EINPROGRESS) {
+ /* The disconnect() op called by tcp_sendmsg_fastopen()/
+ * __inet_stream_connect() can fail, due to looking check,
+ * see mptcp_disconnect().
+ * Attempt it again outside the problematic scope.
+ */
+ if (!mptcp_disconnect(sk, 0))
+ sk->sk_socket->state = SS_UNCONNECTED;
+ }
+
+ return ret;
+}
+
+static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct page_frag *pfrag;
+ struct socket *ssock;
+ size_t copied = 0;
+ int ret = 0;
+ long timeo;
+
+ /* we don't support FASTOPEN yet */
+ if (msg->msg_flags & MSG_FASTOPEN)
+ return -EOPNOTSUPP;
+
+ /* silently ignore everything else */
+ msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL;
+
+ lock_sock(sk);
+
+ ssock = __mptcp_nmpc_socket(msk);
+ if (unlikely(ssock && inet_sk(ssock->sk)->defer_connect)) {
+ int copied_syn = 0;
+
+ ret = mptcp_sendmsg_fastopen(sk, ssock->sk, msg, len, &copied_syn);
+ copied += copied_syn;
+ if (ret == -EINPROGRESS && copied_syn > 0)
+ goto out;
+ else if (ret)
+ goto do_error;
+ }
+
+ 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 do_error;
+ }
+
+ ret = -EPIPE;
+ if (unlikely(sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)))
+ goto do_error;
+
+ pfrag = sk_page_frag(sk);
+
+ while (msg_data_left(msg)) {
+ int total_ts, frag_truesize = 0;
+ struct mptcp_data_frag *dfrag;
+ bool dfrag_collapsed;
+ size_t psize, offset;
+
+ /* reuse tail pfrag, if possible, or carve a new one from the
+ * page allocator
+ */
+ dfrag = mptcp_pending_tail(sk);
+ dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag);
+ if (!dfrag_collapsed) {
+ if (!sk_stream_memory_free(sk))
+ goto wait_for_memory;
+
+ if (!mptcp_page_frag_refill(sk, pfrag))
+ goto wait_for_memory;
+
+ dfrag = mptcp_carve_data_frag(msk, pfrag, pfrag->offset);
+ frag_truesize = dfrag->overhead;
+ }
+
+ /* we do not bound vs wspace, to allow a single packet.
+ * memory accounting will prevent execessive memory usage
+ * anyway
+ */
+ offset = dfrag->offset + dfrag->data_len;
+ psize = pfrag->size - offset;
+ psize = min_t(size_t, psize, msg_data_left(msg));
+ total_ts = psize + frag_truesize;
+
+ if (!sk_wmem_schedule(sk, total_ts))
+ goto wait_for_memory;
+
+ if (copy_page_from_iter(dfrag->page, offset, psize,
+ &msg->msg_iter) != psize) {
+ ret = -EFAULT;
+ goto do_error;
+ }
+
+ /* data successfully copied into the write queue */
+ sk_forward_alloc_add(sk, -total_ts);
+ copied += psize;
+ dfrag->data_len += psize;
+ frag_truesize += psize;
+ pfrag->offset += frag_truesize;
+ WRITE_ONCE(msk->write_seq, msk->write_seq + psize);
+
+ /* charge data on mptcp pending queue to the msk socket
+ * Note: we charge such data both to sk and ssk
+ */
+ sk_wmem_queued_add(sk, frag_truesize);
+ if (!dfrag_collapsed) {
+ get_page(dfrag->page);
+ list_add_tail(&dfrag->list, &msk->rtx_queue);
+ if (!msk->first_pending)
+ WRITE_ONCE(msk->first_pending, dfrag);
+ }
+ pr_debug("msk=%p dfrag at seq=%llu len=%u sent=%u new=%d", msk,
+ dfrag->data_seq, dfrag->data_len, dfrag->already_sent,
+ !dfrag_collapsed);
+
+ continue;
+
+wait_for_memory:
+ mptcp_set_nospace(sk);
+ __mptcp_push_pending(sk, msg->msg_flags);
+ ret = sk_stream_wait_memory(sk, &timeo);
+ if (ret)
+ goto do_error;
+ }
+
+ if (copied)
+ __mptcp_push_pending(sk, msg->msg_flags);
+
+out:
+ release_sock(sk);
+ return copied;
+
+do_error:
+ if (copied)
+ goto out;
+
+ copied = sk_stream_error(sk, msg->msg_flags, ret);
+ goto out;
+}
+
+static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk,
+ struct msghdr *msg,
+ size_t len, int flags,
+ struct scm_timestamping_internal *tss,
+ int *cmsg_flags)
+{
+ struct sk_buff *skb, *tmp;
+ int copied = 0;
+
+ skb_queue_walk_safe(&msk->receive_queue, skb, tmp) {
+ 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;
+
+ if (!(flags & MSG_TRUNC)) {
+ err = skb_copy_datagram_msg(skb, offset, msg, count);
+ if (unlikely(err < 0)) {
+ if (!copied)
+ return err;
+ break;
+ }
+ }
+
+ if (MPTCP_SKB_CB(skb)->has_rxtstamp) {
+ tcp_update_recv_tstamps(skb, tss);
+ *cmsg_flags |= MPTCP_CMSG_TS;
+ }
+
+ copied += count;
+
+ if (count < data_len) {
+ if (!(flags & MSG_PEEK)) {
+ MPTCP_SKB_CB(skb)->offset += count;
+ MPTCP_SKB_CB(skb)->map_seq += count;
+ }
+ break;
+ }
+
+ if (!(flags & MSG_PEEK)) {
+ /* we will bulk release the skb memory later */
+ skb->destructor = NULL;
+ WRITE_ONCE(msk->rmem_released, msk->rmem_released + skb->truesize);
+ __skb_unlink(skb, &msk->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 (READ_ONCE(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,
+ READ_ONCE(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 void __mptcp_update_rmem(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ if (!msk->rmem_released)
+ return;
+
+ atomic_sub(msk->rmem_released, &sk->sk_rmem_alloc);
+ mptcp_rmem_uncharge(sk, msk->rmem_released);
+ WRITE_ONCE(msk->rmem_released, 0);
+}
+
+static void __mptcp_splice_receive_queue(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue);
+}
+
+static bool __mptcp_move_skbs(struct mptcp_sock *msk)
+{
+ struct sock *sk = (struct sock *)msk;
+ unsigned int moved = 0;
+ bool ret, done;
+
+ do {
+ struct sock *ssk = mptcp_subflow_recv_lookup(msk);
+ bool slowpath;
+
+ /* we can have data pending in the subflows only if the msk
+ * receive buffer was full at subflow_data_ready() time,
+ * that is an unlikely slow path.
+ */
+ if (likely(!ssk))
+ break;
+
+ slowpath = lock_sock_fast(ssk);
+ mptcp_data_lock(sk);
+ __mptcp_update_rmem(sk);
+ done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
+ mptcp_data_unlock(sk);
+
+ if (unlikely(ssk->sk_err))
+ __mptcp_error_report(sk);
+ unlock_sock_fast(ssk, slowpath);
+ } while (!done);
+
+ /* acquire the data lock only if some input data is pending */
+ ret = moved > 0;
+ if (!RB_EMPTY_ROOT(&msk->out_of_order_queue) ||
+ !skb_queue_empty_lockless(&sk->sk_receive_queue)) {
+ mptcp_data_lock(sk);
+ __mptcp_update_rmem(sk);
+ ret |= __mptcp_ofo_queue(msk);
+ __mptcp_splice_receive_queue(sk);
+ mptcp_data_unlock(sk);
+ }
+ if (ret)
+ mptcp_check_data_fin((struct sock *)msk);
+ return !skb_queue_empty(&msk->receive_queue);
+}
+
+static unsigned int mptcp_inq_hint(const struct sock *sk)
+{
+ const struct mptcp_sock *msk = mptcp_sk(sk);
+ const struct sk_buff *skb;
+
+ skb = skb_peek(&msk->receive_queue);
+ if (skb) {
+ u64 hint_val = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq;
+
+ if (hint_val >= INT_MAX)
+ return INT_MAX;
+
+ return (unsigned int)hint_val;
+ }
+
+ if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
+ return 1;
+
+ return 0;
+}
+
+static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
+ int flags, int *addr_len)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct scm_timestamping_internal tss;
+ int copied = 0, cmsg_flags = 0;
+ int target;
+ long timeo;
+
+ /* MSG_ERRQUEUE is really a no-op till we support IP_RECVERR */
+ if (unlikely(flags & MSG_ERRQUEUE))
+ return inet_recv_error(sk, msg, len, addr_len);
+
+ lock_sock(sk);
+ if (unlikely(sk->sk_state == TCP_LISTEN)) {
+ copied = -ENOTCONN;
+ goto out_err;
+ }
+
+ timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
+
+ len = min_t(size_t, len, INT_MAX);
+ target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
+
+ if (unlikely(msk->recvmsg_inq))
+ cmsg_flags = MPTCP_CMSG_INQ;
+
+ while (copied < len) {
+ int bytes_read;
+
+ bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags, &tss, &cmsg_flags);
+ if (unlikely(bytes_read < 0)) {
+ if (!copied)
+ copied = bytes_read;
+ goto out_err;
+ }
+
+ copied += bytes_read;
+
+ /* be sure to advertise window change */
+ mptcp_cleanup_rbuf(msk);
+
+ if (skb_queue_empty(&msk->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) {
+ /* race breaker: the shutdown could be after the
+ * previous receive queue check
+ */
+ if (__mptcp_move_skbs(msk))
+ continue;
+ 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);
+ sk_wait_data(sk, &timeo, NULL);
+ }
+
+out_err:
+ if (cmsg_flags && copied >= 0) {
+ if (cmsg_flags & MPTCP_CMSG_TS)
+ tcp_recv_timestamp(msg, sk, &tss);
+
+ if (cmsg_flags & MPTCP_CMSG_INQ) {
+ unsigned int inq = mptcp_inq_hint(sk);
+
+ put_cmsg(msg, SOL_TCP, TCP_CM_INQ, sizeof(inq), &inq);
+ }
+ }
+
+ pr_debug("msk=%p rx queue empty=%d:%d copied=%d",
+ msk, skb_queue_empty_lockless(&sk->sk_receive_queue),
+ skb_queue_empty(&msk->receive_queue), copied);
+ if (!(flags & MSG_PEEK))
+ mptcp_rcv_space_adjust(msk, copied);
+
+ release_sock(sk);
+ return copied;
+}
+
+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;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ bh_lock_sock(sk);
+ if (!sock_owned_by_user(sk)) {
+ /* we need a process context to retransmit */
+ if (!test_and_set_bit(MPTCP_WORK_RTX, &msk->flags))
+ mptcp_schedule_work(sk);
+ } else {
+ /* delegate our work to tcp_release_cb() */
+ __set_bit(MPTCP_RETRANSMIT, &msk->cb_flags);
+ }
+ bh_unlock_sock(sk);
+ sock_put(sk);
+}
+
+static void mptcp_tout_timer(struct timer_list *t)
+{
+ struct sock *sk = from_timer(sk, t, sk_timer);
+
+ mptcp_schedule_work(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(struct mptcp_sock *msk)
+{
+ struct sock *backup = NULL, *pick = NULL;
+ struct mptcp_subflow_context *subflow;
+ int min_stale_count = INT_MAX;
+
+ sock_owned_by_me((const struct sock *)msk);
+
+ if (__mptcp_check_fallback(msk))
+ return NULL;
+
+ 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? skip this */
+ if (!tcp_rtx_and_write_queues_empty(ssk)) {
+ mptcp_pm_subflow_chk_stale(msk, ssk);
+ min_stale_count = min_t(int, min_stale_count, subflow->stale_count);
+ continue;
+ }
+
+ if (subflow->backup) {
+ if (!backup)
+ backup = ssk;
+ continue;
+ }
+
+ if (!pick)
+ pick = ssk;
+ }
+
+ if (pick)
+ return pick;
+
+ /* use backup only if there are no progresses anywhere */
+ return min_stale_count > 1 ? backup : NULL;
+}
+
+static void mptcp_dispose_initial_subflow(struct mptcp_sock *msk)
+{
+ if (msk->subflow) {
+ iput(SOCK_INODE(msk->subflow));
+ WRITE_ONCE(msk->subflow, NULL);
+ }
+}
+
+bool __mptcp_retransmit_pending_data(struct sock *sk)
+{
+ struct mptcp_data_frag *cur, *rtx_head;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ if (__mptcp_check_fallback(mptcp_sk(sk)))
+ return false;
+
+ if (tcp_rtx_and_write_queues_empty(sk))
+ return false;
+
+ /* the closing socket has some data untransmitted and/or unacked:
+ * some data in the mptcp rtx queue has not really xmitted yet.
+ * keep it simple and re-inject the whole mptcp level rtx queue
+ */
+ mptcp_data_lock(sk);
+ __mptcp_clean_una_wakeup(sk);
+ rtx_head = mptcp_rtx_head(sk);
+ if (!rtx_head) {
+ mptcp_data_unlock(sk);
+ return false;
+ }
+
+ msk->recovery_snd_nxt = msk->snd_nxt;
+ msk->recovery = true;
+ mptcp_data_unlock(sk);
+
+ msk->first_pending = rtx_head;
+ msk->snd_burst = 0;
+
+ /* be sure to clear the "sent status" on all re-injected fragments */
+ list_for_each_entry(cur, &msk->rtx_queue, list) {
+ if (!cur->already_sent)
+ break;
+ cur->already_sent = 0;
+ }
+
+ return true;
+}
+
+/* flags for __mptcp_close_ssk() */
+#define MPTCP_CF_PUSH BIT(1)
+#define MPTCP_CF_FASTCLOSE BIT(2)
+
+/* be sure to send a reset only if the caller asked for it, also
+ * clean completely the subflow status when the subflow reaches
+ * TCP_CLOSE state
+ */
+static void __mptcp_subflow_disconnect(struct sock *ssk,
+ struct mptcp_subflow_context *subflow,
+ unsigned int flags)
+{
+ if (((1 << ssk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) ||
+ (flags & MPTCP_CF_FASTCLOSE)) {
+ /* The MPTCP code never wait on the subflow sockets, TCP-level
+ * disconnect should never fail
+ */
+ WARN_ON_ONCE(tcp_disconnect(ssk, 0));
+ mptcp_subflow_ctx_reset(subflow);
+ } else {
+ tcp_shutdown(ssk, SEND_SHUTDOWN);
+ }
+}
+
+/* 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.
+ */
+static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
+ struct mptcp_subflow_context *subflow,
+ unsigned int flags)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ bool dispose_it, need_push = false;
+
+ /* If the first subflow moved to a close state before accept, e.g. due
+ * to an incoming reset or listener shutdown, the subflow socket is
+ * already deleted by inet_child_forget() and the mptcp socket can't
+ * survive too.
+ */
+ if (msk->in_accept_queue && msk->first == ssk &&
+ (sock_flag(sk, SOCK_DEAD) || sock_flag(ssk, SOCK_DEAD))) {
+ /* ensure later check in mptcp_worker() will dispose the msk */
+ mptcp_set_close_tout(sk, tcp_jiffies32 - (TCP_TIMEWAIT_LEN + 1));
+ sock_set_flag(sk, SOCK_DEAD);
+ lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
+ mptcp_subflow_drop_ctx(ssk);
+ goto out_release;
+ }
+
+ dispose_it = !msk->subflow || ssk != msk->subflow->sk;
+ if (dispose_it)
+ list_del(&subflow->node);
+
+ lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
+
+ if ((flags & MPTCP_CF_FASTCLOSE) && !__mptcp_check_fallback(msk)) {
+ /* be sure to force the tcp_close path
+ * to generate the egress reset
+ */
+ ssk->sk_lingertime = 0;
+ sock_set_flag(ssk, SOCK_LINGER);
+ subflow->send_fastclose = 1;
+ }
+
+ need_push = (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(sk);
+ if (!dispose_it) {
+ __mptcp_subflow_disconnect(ssk, subflow, flags);
+ msk->subflow->state = SS_UNCONNECTED;
+ release_sock(ssk);
+
+ goto out;
+ }
+
+ subflow->disposable = 1;
+
+ /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops
+ * the ssk has been already destroyed, we just need to release the
+ * reference owned by msk;
+ */
+ if (!inet_csk(ssk)->icsk_ulp_ops) {
+ WARN_ON_ONCE(!sock_flag(ssk, SOCK_DEAD));
+ kfree_rcu(subflow, rcu);
+ } else {
+ /* otherwise tcp will dispose of the ssk and subflow ctx */
+ __tcp_close(ssk, 0);
+
+ /* close acquired an extra ref */
+ __sock_put(ssk);
+ }
+
+out_release:
+ __mptcp_subflow_error_report(sk, ssk);
+ release_sock(ssk);
+
+ sock_put(ssk);
+
+ if (ssk == msk->first)
+ WRITE_ONCE(msk->first, NULL);
+
+out:
+ if (ssk == msk->last_snd)
+ msk->last_snd = NULL;
+
+ if (need_push)
+ __mptcp_push_pending(sk, 0);
+
+ /* Catch every 'all subflows closed' scenario, including peers silently
+ * closing them, e.g. due to timeout.
+ * For established sockets, allow an additional timeout before closing,
+ * as the protocol can still create more subflows.
+ */
+ if (list_is_singular(&msk->conn_list) && msk->first &&
+ inet_sk_state_load(msk->first) == TCP_CLOSE) {
+ if (sk->sk_state != TCP_ESTABLISHED ||
+ msk->in_accept_queue || sock_flag(sk, SOCK_DEAD)) {
+ inet_sk_state_store(sk, TCP_CLOSE);
+ mptcp_close_wake_up(sk);
+ } else {
+ mptcp_start_tout_timer(sk);
+ }
+ }
+}
+
+void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
+ struct mptcp_subflow_context *subflow)
+{
+ if (sk->sk_state == TCP_ESTABLISHED)
+ mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL);
+
+ /* subflow aborted before reaching the fully_established status
+ * attempt the creation of the next subflow
+ */
+ mptcp_pm_subflow_check_next(mptcp_sk(sk), ssk, subflow);
+
+ __mptcp_close_ssk(sk, ssk, subflow, MPTCP_CF_PUSH);
+}
+
+static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu)
+{
+ return 0;
+}
+
+static void __mptcp_close_subflow(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow, *tmp;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ might_sleep();
+
+ mptcp_for_each_subflow_safe(msk, subflow, tmp) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ if (inet_sk_state_load(ssk) != TCP_CLOSE)
+ continue;
+
+ /* 'subflow_data_ready' will re-sched once rx queue is empty */
+ if (!skb_queue_empty_lockless(&ssk->sk_receive_queue))
+ continue;
+
+ mptcp_close_ssk(sk, ssk, subflow);
+ }
+
+}
+
+static bool mptcp_close_tout_expired(const struct sock *sk)
+{
+ if (!inet_csk(sk)->icsk_mtup.probe_timestamp ||
+ sk->sk_state == TCP_CLOSE)
+ return false;
+
+ return time_after32(tcp_jiffies32,
+ inet_csk(sk)->icsk_mtup.probe_timestamp + TCP_TIMEWAIT_LEN);
+}
+
+static void mptcp_check_fastclose(struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow, *tmp;
+ struct sock *sk = &msk->sk.icsk_inet.sk;
+
+ if (likely(!READ_ONCE(msk->rcv_fastclose)))
+ return;
+
+ mptcp_token_destroy(msk);
+
+ mptcp_for_each_subflow_safe(msk, subflow, tmp) {
+ struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
+ bool slow;
+
+ slow = lock_sock_fast(tcp_sk);
+ if (tcp_sk->sk_state != TCP_CLOSE) {
+ tcp_send_active_reset(tcp_sk, GFP_ATOMIC);
+ tcp_set_state(tcp_sk, TCP_CLOSE);
+ }
+ unlock_sock_fast(tcp_sk, slow);
+ }
+
+ /* Mirror the tcp_reset() error propagation */
+ switch (sk->sk_state) {
+ case TCP_SYN_SENT:
+ WRITE_ONCE(sk->sk_err, ECONNREFUSED);
+ break;
+ case TCP_CLOSE_WAIT:
+ WRITE_ONCE(sk->sk_err, EPIPE);
+ break;
+ case TCP_CLOSE:
+ return;
+ default:
+ WRITE_ONCE(sk->sk_err, ECONNRESET);
+ }
+
+ inet_sk_state_store(sk, TCP_CLOSE);
+ WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
+ smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
+ set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags);
+
+ /* the calling mptcp_worker will properly destroy the socket */
+ if (sock_flag(sk, SOCK_DEAD))
+ return;
+
+ sk->sk_state_change(sk);
+ sk_error_report(sk);
+}
+
+static void __mptcp_retrans(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct mptcp_sendmsg_info info = {};
+ struct mptcp_data_frag *dfrag;
+ size_t copied = 0;
+ struct sock *ssk;
+ int ret;
+
+ mptcp_clean_una_wakeup(sk);
+
+ /* first check ssk: need to kick "stale" logic */
+ ssk = mptcp_subflow_get_retrans(msk);
+ dfrag = mptcp_rtx_head(sk);
+ if (!dfrag) {
+ if (mptcp_data_fin_enabled(msk)) {
+ struct inet_connection_sock *icsk = inet_csk(sk);
+
+ icsk->icsk_retransmits++;
+ mptcp_set_datafin_timeout(sk);
+ mptcp_send_ack(msk);
+
+ goto reset_timer;
+ }
+
+ if (!mptcp_send_head(sk))
+ return;
+
+ goto reset_timer;
+ }
+
+ if (!ssk)
+ goto reset_timer;
+
+ lock_sock(ssk);
+
+ /* limit retransmission to the bytes already sent on some subflows */
+ info.sent = 0;
+ info.limit = READ_ONCE(msk->csum_enabled) ? dfrag->data_len : dfrag->already_sent;
+ while (info.sent < info.limit) {
+ ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
+ if (ret <= 0)
+ break;
+
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS);
+ copied += ret;
+ info.sent += ret;
+ }
+ if (copied) {
+ dfrag->already_sent = max(dfrag->already_sent, info.sent);
+ tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
+ info.size_goal);
+ WRITE_ONCE(msk->allow_infinite_fallback, false);
+ }
+
+ release_sock(ssk);
+
+reset_timer:
+ mptcp_check_and_set_pending(sk);
+
+ if (!mptcp_rtx_timer_pending(sk))
+ mptcp_reset_rtx_timer(sk);
+}
+
+/* schedule the timeout timer for the relevant event: either close timeout
+ * or mp_fail timeout. The close timeout takes precedence on the mp_fail one
+ */
+void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout)
+{
+ struct sock *sk = (struct sock *)msk;
+ unsigned long timeout, close_timeout;
+
+ if (!fail_tout && !inet_csk(sk)->icsk_mtup.probe_timestamp)
+ return;
+
+ close_timeout = inet_csk(sk)->icsk_mtup.probe_timestamp - tcp_jiffies32 + jiffies +
+ TCP_TIMEWAIT_LEN;
+
+ /* the close timeout takes precedence on the fail one, and here at least one of
+ * them is active
+ */
+ timeout = inet_csk(sk)->icsk_mtup.probe_timestamp ? close_timeout : fail_tout;
+
+ sk_reset_timer(sk, &sk->sk_timer, timeout);
+}
+
+static void mptcp_mp_fail_no_response(struct mptcp_sock *msk)
+{
+ struct sock *ssk = msk->first;
+ bool slow;
+
+ if (!ssk)
+ return;
+
+ pr_debug("MP_FAIL doesn't respond, reset the subflow");
+
+ slow = lock_sock_fast(ssk);
+ mptcp_subflow_reset(ssk);
+ WRITE_ONCE(mptcp_subflow_ctx(ssk)->fail_tout, 0);
+ unlock_sock_fast(ssk, slow);
+}
+
+static void mptcp_do_fastclose(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow, *tmp;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ mptcp_for_each_subflow_safe(msk, subflow, tmp)
+ __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow),
+ subflow, MPTCP_CF_FASTCLOSE);
+}
+
+static void mptcp_worker(struct work_struct *work)
+{
+ struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
+ struct sock *sk = &msk->sk.icsk_inet.sk;
+ unsigned long fail_tout;
+ int state;
+
+ lock_sock(sk);
+ state = sk->sk_state;
+ if (unlikely((1 << state) & (TCPF_CLOSE | TCPF_LISTEN)))
+ goto unlock;
+
+ mptcp_check_fastclose(msk);
+
+ mptcp_pm_nl_work(msk);
+
+ if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
+ mptcp_check_for_eof(msk);
+
+ mptcp_check_send_data_fin(sk);
+ mptcp_check_data_fin_ack(sk);
+ mptcp_check_data_fin(sk);
+
+ if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
+ __mptcp_close_subflow(sk);
+
+ if (mptcp_close_tout_expired(sk)) {
+ inet_sk_state_store(sk, TCP_CLOSE);
+ mptcp_do_fastclose(sk);
+ mptcp_close_wake_up(sk);
+ }
+
+ if (sock_flag(sk, SOCK_DEAD) && sk->sk_state == TCP_CLOSE) {
+ __mptcp_destroy_sock(sk);
+ goto unlock;
+ }
+
+ if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
+ __mptcp_retrans(sk);
+
+ fail_tout = msk->first ? READ_ONCE(mptcp_subflow_ctx(msk->first)->fail_tout) : 0;
+ if (fail_tout && time_after(jiffies, fail_tout))
+ mptcp_mp_fail_no_response(msk);
+
+unlock:
+ release_sock(sk);
+ sock_put(sk);
+}
+
+static int __mptcp_init_sock(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ INIT_LIST_HEAD(&msk->conn_list);
+ INIT_LIST_HEAD(&msk->join_list);
+ INIT_LIST_HEAD(&msk->rtx_queue);
+ INIT_WORK(&msk->work, mptcp_worker);
+ __skb_queue_head_init(&msk->receive_queue);
+ msk->out_of_order_queue = RB_ROOT;
+ msk->first_pending = NULL;
+ msk->rmem_fwd_alloc = 0;
+ WRITE_ONCE(msk->rmem_released, 0);
+ msk->timer_ival = TCP_RTO_MIN;
+
+ WRITE_ONCE(msk->first, NULL);
+ inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss;
+ WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
+ WRITE_ONCE(msk->allow_infinite_fallback, true);
+ msk->recovery = false;
+
+ 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);
+ timer_setup(&sk->sk_timer, mptcp_tout_timer, 0);
+
+ return 0;
+}
+
+static void mptcp_ca_reset(struct sock *sk)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+
+ tcp_assign_congestion_control(sk);
+ strcpy(mptcp_sk(sk)->ca_name, icsk->icsk_ca_ops->name);
+
+ /* no need to keep a reference to the ops, the name will suffice */
+ tcp_cleanup_congestion_control(sk);
+ icsk->icsk_ca_ops = NULL;
+}
+
+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;
+
+ /* fetch the ca name; do it outside __mptcp_init_sock(), so that clone will
+ * propagate the correct value
+ */
+ mptcp_ca_reset(sk);
+
+ sk_sockets_allocated_inc(sk);
+ sk->sk_rcvbuf = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[1]);
+ sk->sk_sndbuf = READ_ONCE(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;
+
+ WRITE_ONCE(msk->first_pending, NULL);
+ list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list)
+ dfrag_clear(sk, dfrag);
+}
+
+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:
+ WARN_ON_ONCE(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);
+
+ /* simulate the data_fin ack reception to let the state
+ * machine move forward
+ */
+ WRITE_ONCE(mptcp_sk(sk)->snd_una, mptcp_sk(sk)->snd_nxt);
+ mptcp_schedule_work(sk);
+ } else {
+ pr_debug("Sending DATA_FIN on subflow %p", ssk);
+ tcp_send_ack(ssk);
+ if (!mptcp_rtx_timer_pending(sk))
+ mptcp_reset_rtx_timer(sk);
+ }
+ 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_check_send_data_fin(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ pr_debug("msk=%p snd_data_fin_enable=%d pending=%d snd_nxt=%llu write_seq=%llu",
+ msk, msk->snd_data_fin_enable, !!mptcp_send_head(sk),
+ msk->snd_nxt, msk->write_seq);
+
+ /* we still need to enqueue subflows or not really shutting down,
+ * skip this
+ */
+ if (!msk->snd_data_fin_enable || msk->snd_nxt + 1 != msk->write_seq ||
+ mptcp_send_head(sk))
+ return;
+
+ WRITE_ONCE(msk->snd_nxt, msk->write_seq);
+
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
+
+ mptcp_subflow_shutdown(sk, tcp_sk, SEND_SHUTDOWN);
+ }
+}
+
+static void __mptcp_wr_shutdown(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ pr_debug("msk=%p snd_data_fin_enable=%d shutdown=%x state=%d pending=%d",
+ msk, msk->snd_data_fin_enable, sk->sk_shutdown, sk->sk_state,
+ !!mptcp_send_head(sk));
+
+ /* will be ignored by fallback sockets */
+ WRITE_ONCE(msk->write_seq, msk->write_seq + 1);
+ WRITE_ONCE(msk->snd_data_fin_enable, 1);
+
+ mptcp_check_send_data_fin(sk);
+}
+
+static void __mptcp_destroy_sock(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ pr_debug("msk=%p", msk);
+
+ might_sleep();
+
+ mptcp_stop_rtx_timer(sk);
+ sk_stop_timer(sk, &sk->sk_timer);
+ msk->pm.status = 0;
+
+ sk->sk_prot->destroy(sk);
+
+ WARN_ON_ONCE(msk->rmem_fwd_alloc);
+ WARN_ON_ONCE(msk->rmem_released);
+ sk_stream_kill_queues(sk);
+ xfrm_sk_free_policy(sk);
+
+ sk_refcnt_debug_release(sk);
+ sock_put(sk);
+}
+
+void __mptcp_unaccepted_force_close(struct sock *sk)
+{
+ sock_set_flag(sk, SOCK_DEAD);
+ inet_sk_state_store(sk, TCP_CLOSE);
+ mptcp_do_fastclose(sk);
+ __mptcp_destroy_sock(sk);
+}
+
+static __poll_t mptcp_check_readable(struct mptcp_sock *msk)
+{
+ /* Concurrent splices from sk_receive_queue into receive_queue will
+ * always show at least one non-empty queue when checked in this order.
+ */
+ if (skb_queue_empty_lockless(&((struct sock *)msk)->sk_receive_queue) &&
+ skb_queue_empty_lockless(&msk->receive_queue))
+ return 0;
+
+ return EPOLLIN | EPOLLRDNORM;
+}
+
+static void mptcp_check_listen_stop(struct sock *sk)
+{
+ struct sock *ssk;
+
+ if (inet_sk_state_load(sk) != TCP_LISTEN)
+ return;
+
+ ssk = mptcp_sk(sk)->first;
+ if (WARN_ON_ONCE(!ssk || inet_sk_state_load(ssk) != TCP_LISTEN))
+ return;
+
+ lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
+ tcp_set_state(ssk, TCP_CLOSE);
+ mptcp_subflow_queue_clean(sk, ssk);
+ inet_csk_listen_stop(ssk);
+ release_sock(ssk);
+}
+
+bool __mptcp_close(struct sock *sk, long timeout)
+{
+ struct mptcp_subflow_context *subflow;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ bool do_cancel_work = false;
+ int subflows_alive = 0;
+
+ WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
+
+ if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) {
+ mptcp_check_listen_stop(sk);
+ inet_sk_state_store(sk, TCP_CLOSE);
+ goto cleanup;
+ }
+
+ if (mptcp_check_readable(msk)) {
+ /* the msk has read data, do the MPTCP equivalent of TCP reset */
+ inet_sk_state_store(sk, TCP_CLOSE);
+ mptcp_do_fastclose(sk);
+ } else if (mptcp_close_state(sk)) {
+ __mptcp_wr_shutdown(sk);
+ }
+
+ sk_stream_wait_close(sk, timeout);
+
+cleanup:
+ /* orphan all the subflows */
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+ bool slow = lock_sock_fast_nested(ssk);
+
+ subflows_alive += ssk->sk_state != TCP_CLOSE;
+
+ /* since the close timeout takes precedence on the fail one,
+ * cancel the latter
+ */
+ if (ssk == msk->first)
+ subflow->fail_tout = 0;
+
+ /* detach from the parent socket, but allow data_ready to
+ * push incoming data into the mptcp stack, to properly ack it
+ */
+ ssk->sk_socket = NULL;
+ ssk->sk_wq = NULL;
+ unlock_sock_fast(ssk, slow);
+ }
+ sock_orphan(sk);
+
+ /* all the subflows are closed, only timeout can change the msk
+ * state, let's not keep resources busy for no reasons
+ */
+ if (subflows_alive == 0)
+ inet_sk_state_store(sk, TCP_CLOSE);
+
+ sock_hold(sk);
+ pr_debug("msk=%p state=%d", sk, sk->sk_state);
+ if (mptcp_sk(sk)->token)
+ mptcp_event(MPTCP_EVENT_CLOSED, msk, NULL, GFP_KERNEL);
+
+ if (sk->sk_state == TCP_CLOSE) {
+ __mptcp_destroy_sock(sk);
+ do_cancel_work = true;
+ } else {
+ mptcp_start_tout_timer(sk);
+ }
+
+ return do_cancel_work;
+}
+
+static void mptcp_close(struct sock *sk, long timeout)
+{
+ bool do_cancel_work;
+
+ lock_sock(sk);
+
+ do_cancel_work = __mptcp_close(sk, timeout);
+ release_sock(sk);
+ if (do_cancel_work)
+ mptcp_cancel_work(sk);
+
+ sock_put(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)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ /* We are on the fastopen error path. We can't call straight into the
+ * subflows cleanup code due to lock nesting (we are already under
+ * msk->firstsocket lock).
+ */
+ if (msk->fastopening)
+ return -EBUSY;
+
+ mptcp_check_listen_stop(sk);
+ inet_sk_state_store(sk, TCP_CLOSE);
+
+ mptcp_stop_rtx_timer(sk);
+ mptcp_stop_tout_timer(sk);
+
+ if (mptcp_sk(sk)->token)
+ mptcp_event(MPTCP_EVENT_CLOSED, mptcp_sk(sk), NULL, GFP_KERNEL);
+
+ /* msk->subflow is still intact, the following will not free the first
+ * subflow
+ */
+ mptcp_destroy_common(msk, MPTCP_CF_FASTCLOSE);
+ msk->last_snd = NULL;
+ WRITE_ONCE(msk->flags, 0);
+ msk->cb_flags = 0;
+ msk->push_pending = 0;
+ msk->recovery = false;
+ msk->can_ack = false;
+ msk->fully_established = false;
+ msk->rcv_data_fin = false;
+ msk->snd_data_fin_enable = false;
+ msk->rcv_fastclose = false;
+ msk->use_64bit_ack = false;
+ WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
+ mptcp_pm_data_reset(msk);
+ mptcp_ca_reset(sk);
+
+ WRITE_ONCE(sk->sk_shutdown, 0);
+ sk_error_report(sk);
+ 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_init(const struct sock *sk,
+ const struct mptcp_options_received *mp_opt,
+ struct sock *ssk,
+ 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;
+ WRITE_ONCE(msk->subflow, NULL);
+ msk->in_accept_queue = 1;
+ WRITE_ONCE(msk->fully_established, false);
+ if (mp_opt->suboptions & OPTION_MPTCP_CSUMREQD)
+ WRITE_ONCE(msk->csum_enabled, true);
+
+ msk->write_seq = subflow_req->idsn + 1;
+ msk->snd_nxt = msk->write_seq;
+ msk->snd_una = msk->write_seq;
+ msk->wnd_end = msk->snd_nxt + req->rsk_rcv_wnd;
+ msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq;
+
+ if (mp_opt->suboptions & OPTIONS_MPTCP_MPC) {
+ 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);
+ atomic64_set(&msk->rcv_wnd_sent, ack_seq);
+ }
+
+ sock_reset_flag(nsk, SOCK_RCU_FREE);
+ security_inet_csk_clone(nsk, req);
+
+ /* this can't race with mptcp_close(), as the msk is
+ * not yet exposted to user-space
+ */
+ inet_sk_state_store(nsk, TCP_ESTABLISHED);
+
+ /* The msk maintain a ref to each subflow in the connections list */
+ WRITE_ONCE(msk->first, ssk);
+ list_add(&mptcp_subflow_ctx(ssk)->node, &msk->conn_list);
+ sock_hold(ssk);
+
+ /* new mpc subflow takes ownership of the newly
+ * created mptcp socket
+ */
+ mptcp_token_accept(subflow_req, msk);
+
+ /* set msk addresses early to ensure mptcp_pm_get_local_id()
+ * uses the correct data
+ */
+ mptcp_copy_inaddrs(nsk, ssk);
+ mptcp_propagate_sndbuf(nsk, ssk);
+
+ mptcp_rcv_space_init(msk, ssk);
+ bh_unlock_sock(nsk);
+
+ /* note: the newly allocated socket refcount is 2 now */
+ 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;
+
+ WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd);
+}
+
+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 = READ_ONCE(msk->subflow);
+ 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;
+
+ 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;
+ }
+
+ newsk = new_mptcp_sock;
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEPASSIVEACK);
+ } 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, unsigned int flags)
+{
+ struct mptcp_subflow_context *subflow, *tmp;
+ struct sock *sk = (struct sock *)msk;
+
+ __mptcp_clear_xmit(sk);
+
+ /* join list will be eventually flushed (with rst) at sock lock release time */
+ mptcp_for_each_subflow_safe(msk, subflow, tmp)
+ __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), subflow, flags);
+
+ /* move to sk_receive_queue, sk_stream_kill_queues will purge it */
+ mptcp_data_lock(sk);
+ skb_queue_splice_tail_init(&msk->receive_queue, &sk->sk_receive_queue);
+ __skb_queue_purge(&sk->sk_receive_queue);
+ skb_rbtree_purge(&msk->out_of_order_queue);
+ mptcp_data_unlock(sk);
+
+ /* move all the rx fwd alloc into the sk_mem_reclaim_final in
+ * inet_sock_destruct() will dispose it
+ */
+ sk_forward_alloc_add(sk, msk->rmem_fwd_alloc);
+ WRITE_ONCE(msk->rmem_fwd_alloc, 0);
+ mptcp_token_destroy(msk);
+ mptcp_pm_free_anno_list(msk);
+ mptcp_free_local_addr_list(msk);
+}
+
+static void mptcp_destroy(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ /* clears msk->subflow, allowing the following to close
+ * even the initial subflow
+ */
+ mptcp_dispose_initial_subflow(msk);
+ mptcp_destroy_common(msk, 0);
+ sk_sockets_allocated_dec(sk);
+}
+
+void __mptcp_data_acked(struct sock *sk)
+{
+ if (!sock_owned_by_user(sk))
+ __mptcp_clean_una(sk);
+ else
+ __set_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->cb_flags);
+
+ if (mptcp_pending_data_fin_ack(sk))
+ mptcp_schedule_work(sk);
+}
+
+void __mptcp_check_push(struct sock *sk, struct sock *ssk)
+{
+ if (!mptcp_send_head(sk))
+ return;
+
+ if (!sock_owned_by_user(sk)) {
+ struct sock *xmit_ssk = mptcp_subflow_get_send(mptcp_sk(sk));
+
+ if (xmit_ssk == ssk)
+ __mptcp_subflow_push_pending(sk, ssk);
+ else if (xmit_ssk)
+ mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk), MPTCP_DELEGATE_SEND);
+ } else {
+ __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags);
+ }
+}
+
+#define MPTCP_FLAGS_PROCESS_CTX_NEED (BIT(MPTCP_PUSH_PENDING) | \
+ BIT(MPTCP_RETRANSMIT) | \
+ BIT(MPTCP_FLUSH_JOIN_LIST))
+
+/* processes deferred events and flush wmem */
+static void mptcp_release_cb(struct sock *sk)
+ __must_hold(&sk->sk_lock.slock)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ for (;;) {
+ unsigned long flags = (msk->cb_flags & MPTCP_FLAGS_PROCESS_CTX_NEED) |
+ msk->push_pending;
+ struct list_head join_list;
+
+ if (!flags)
+ break;
+
+ INIT_LIST_HEAD(&join_list);
+ list_splice_init(&msk->join_list, &join_list);
+
+ /* the following actions acquire the subflow socket lock
+ *
+ * 1) can't be invoked in atomic scope
+ * 2) must avoid ABBA deadlock with msk socket spinlock: the RX
+ * datapath acquires the msk socket spinlock while helding
+ * the subflow socket lock
+ */
+ msk->push_pending = 0;
+ msk->cb_flags &= ~flags;
+ spin_unlock_bh(&sk->sk_lock.slock);
+
+ if (flags & BIT(MPTCP_FLUSH_JOIN_LIST))
+ __mptcp_flush_join_list(sk, &join_list);
+ if (flags & BIT(MPTCP_PUSH_PENDING))
+ __mptcp_push_pending(sk, 0);
+ if (flags & BIT(MPTCP_RETRANSMIT))
+ __mptcp_retrans(sk);
+
+ cond_resched();
+ spin_lock_bh(&sk->sk_lock.slock);
+ }
+
+ if (__test_and_clear_bit(MPTCP_CLEAN_UNA, &msk->cb_flags))
+ __mptcp_clean_una_wakeup(sk);
+ if (unlikely(msk->cb_flags)) {
+ /* be sure to set the current sk state before tacking actions
+ * depending on sk_state, that is processing MPTCP_ERROR_REPORT
+ */
+ if (__test_and_clear_bit(MPTCP_CONNECTED, &msk->cb_flags))
+ __mptcp_set_connected(sk);
+ if (__test_and_clear_bit(MPTCP_ERROR_REPORT, &msk->cb_flags))
+ __mptcp_error_report(sk);
+ if (__test_and_clear_bit(MPTCP_RESET_SCHEDULER, &msk->cb_flags))
+ msk->last_snd = NULL;
+ }
+
+ __mptcp_update_rmem(sk);
+}
+
+/* MP_JOIN client subflow must wait for 4th ack before sending any data:
+ * TCP can't schedule delack timer before the subflow is fully established.
+ * MPTCP uses the delack timer to do 3rd ack retransmissions
+ */
+static void schedule_3rdack_retransmission(struct sock *ssk)
+{
+ struct inet_connection_sock *icsk = inet_csk(ssk);
+ struct tcp_sock *tp = tcp_sk(ssk);
+ unsigned long timeout;
+
+ if (mptcp_subflow_ctx(ssk)->fully_established)
+ return;
+
+ /* reschedule with a timeout above RTT, as we must look only for drop */
+ if (tp->srtt_us)
+ timeout = usecs_to_jiffies(tp->srtt_us >> (3 - 1));
+ else
+ timeout = TCP_TIMEOUT_INIT;
+ timeout += jiffies;
+
+ WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER);
+ icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
+ icsk->icsk_ack.timeout = timeout;
+ sk_reset_timer(ssk, &icsk->icsk_delack_timer, timeout);
+}
+
+void mptcp_subflow_process_delegated(struct sock *ssk, long status)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ struct sock *sk = subflow->conn;
+
+ if (status & BIT(MPTCP_DELEGATE_SEND)) {
+ mptcp_data_lock(sk);
+ if (!sock_owned_by_user(sk))
+ __mptcp_subflow_push_pending(sk, ssk);
+ else
+ __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags);
+ mptcp_data_unlock(sk);
+ }
+ if (status & BIT(MPTCP_DELEGATE_ACK))
+ schedule_3rdack_retransmission(ssk);
+}
+
+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 = msk->subflow;
+ 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->snd_nxt, msk->write_seq);
+ WRITE_ONCE(msk->ack_seq, ack_seq);
+ WRITE_ONCE(msk->can_ack, 1);
+ WRITE_ONCE(msk->snd_una, msk->write_seq);
+ atomic64_set(&msk->rcv_wnd_sent, ack_seq);
+
+ mptcp_pm_new_connection(msk, ssk, 0);
+
+ mptcp_rcv_space_init(msk, ssk);
+}
+
+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 *ssk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ struct mptcp_sock *msk = mptcp_sk(subflow->conn);
+ struct sock *parent = (void *)msk;
+ bool ret = true;
+
+ pr_debug("msk=%p, subflow=%p", msk, subflow);
+
+ /* mptcp socket already closing? */
+ if (!mptcp_is_fully_established(parent)) {
+ subflow->reset_reason = MPTCP_RST_EMPTCP;
+ return false;
+ }
+
+ /* active subflow, already present inside the conn_list */
+ if (!list_empty(&subflow->node)) {
+ mptcp_subflow_joined(msk, ssk);
+ return true;
+ }
+
+ if (!mptcp_pm_allow_new_subflow(msk))
+ goto err_prohibited;
+
+ /* If we can't acquire msk socket lock here, let the release callback
+ * handle it
+ */
+ mptcp_data_lock(parent);
+ if (!sock_owned_by_user(parent)) {
+ ret = __mptcp_finish_join(msk, ssk);
+ if (ret) {
+ sock_hold(ssk);
+ list_add_tail(&subflow->node, &msk->conn_list);
+ }
+ } else {
+ sock_hold(ssk);
+ list_add_tail(&subflow->node, &msk->join_list);
+ __set_bit(MPTCP_FLUSH_JOIN_LIST, &msk->cb_flags);
+ }
+ mptcp_data_unlock(parent);
+
+ if (!ret) {
+err_prohibited:
+ subflow->reset_reason = MPTCP_RST_EPROHIBIT;
+ return false;
+ }
+
+ return true;
+}
+
+static void mptcp_shutdown(struct sock *sk, int how)
+{
+ pr_debug("sk=%p, how=%d", sk, how);
+
+ if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk))
+ __mptcp_wr_shutdown(sk);
+}
+
+static int mptcp_forward_alloc_get(const struct sock *sk)
+{
+ return READ_ONCE(sk->sk_forward_alloc) +
+ READ_ONCE(mptcp_sk(sk)->rmem_fwd_alloc);
+}
+
+static int mptcp_ioctl_outq(const struct mptcp_sock *msk, u64 v)
+{
+ const struct sock *sk = (void *)msk;
+ u64 delta;
+
+ if (sk->sk_state == TCP_LISTEN)
+ return -EINVAL;
+
+ if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
+ return 0;
+
+ delta = msk->write_seq - v;
+ if (__mptcp_check_fallback(msk) && msk->first) {
+ struct tcp_sock *tp = tcp_sk(msk->first);
+
+ /* the first subflow is disconnected after close - see
+ * __mptcp_close_ssk(). tcp_disconnect() moves the write_seq
+ * so ignore that status, too.
+ */
+ if (!((1 << msk->first->sk_state) &
+ (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE)))
+ delta += READ_ONCE(tp->write_seq) - tp->snd_una;
+ }
+ if (delta > INT_MAX)
+ delta = INT_MAX;
+
+ return (int)delta;
+}
+
+static int mptcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ bool slow;
+ int answ;
+
+ switch (cmd) {
+ case SIOCINQ:
+ if (sk->sk_state == TCP_LISTEN)
+ return -EINVAL;
+
+ lock_sock(sk);
+ __mptcp_move_skbs(msk);
+ answ = mptcp_inq_hint(sk);
+ release_sock(sk);
+ break;
+ case SIOCOUTQ:
+ slow = lock_sock_fast(sk);
+ answ = mptcp_ioctl_outq(msk, READ_ONCE(msk->snd_una));
+ unlock_sock_fast(sk, slow);
+ break;
+ case SIOCOUTQNSD:
+ slow = lock_sock_fast(sk);
+ answ = mptcp_ioctl_outq(msk, msk->snd_nxt);
+ unlock_sock_fast(sk, slow);
+ break;
+ default:
+ return -ENOIOCTLCMD;
+ }
+
+ return put_user(answ, (int __user *)arg);
+}
+
+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_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
+{
+ struct mptcp_subflow_context *subflow;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct socket *ssock;
+ int err = -EINVAL;
+
+ ssock = __mptcp_nmpc_socket(msk);
+ if (!ssock)
+ return -EINVAL;
+
+ mptcp_token_destroy(msk);
+ inet_sk_state_store(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_INC_STATS(sock_net(ssock->sk), MPTCP_MIB_TOKENFALLBACKINIT);
+ mptcp_subflow_early_fallback(msk, subflow);
+ }
+ if (likely(!__mptcp_check_fallback(msk)))
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVE);
+
+ /* if reaching here via the fastopen/sendmsg path, the caller already
+ * acquired the subflow socket lock, too.
+ */
+ if (msk->fastopening)
+ err = __inet_stream_connect(ssock, uaddr, addr_len, O_NONBLOCK, 1);
+ else
+ err = inet_stream_connect(ssock, uaddr, addr_len, O_NONBLOCK);
+ inet_sk(sk)->defer_connect = inet_sk(ssock->sk)->defer_connect;
+
+ /* on successful connect, the msk state will be moved to established by
+ * subflow_finish_connect()
+ */
+ if (unlikely(err && err != -EINPROGRESS)) {
+ inet_sk_state_store(sk, inet_sk_state_load(ssock->sk));
+ return err;
+ }
+
+ mptcp_copy_inaddrs(sk, ssock->sk);
+
+ /* silence EINPROGRESS and let the caller inet_stream_connect
+ * handle the connection in progress
+ */
+ return 0;
+}
+
+static struct proto mptcp_prot = {
+ .name = "MPTCP",
+ .owner = THIS_MODULE,
+ .init = mptcp_init_sock,
+ .connect = mptcp_connect,
+ .disconnect = mptcp_disconnect,
+ .close = mptcp_close,
+ .accept = mptcp_accept,
+ .setsockopt = mptcp_setsockopt,
+ .getsockopt = mptcp_getsockopt,
+ .shutdown = mptcp_shutdown,
+ .destroy = mptcp_destroy,
+ .sendmsg = mptcp_sendmsg,
+ .ioctl = mptcp_ioctl,
+ .recvmsg = mptcp_recvmsg,
+ .release_cb = mptcp_release_cb,
+ .hash = mptcp_hash,
+ .unhash = mptcp_unhash,
+ .get_port = mptcp_get_port,
+ .forward_alloc_get = mptcp_forward_alloc_get,
+ .sockets_allocated = &mptcp_sockets_allocated,
+
+ .memory_allocated = &tcp_memory_allocated,
+ .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc,
+
+ .memory_pressure = &tcp_memory_pressure,
+ .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 int mptcp_listen(struct socket *sock, int backlog)
+{
+ struct mptcp_sock *msk = mptcp_sk(sock->sk);
+ struct sock *sk = sock->sk;
+ struct socket *ssock;
+ int err;
+
+ pr_debug("msk=%p", msk);
+
+ lock_sock(sk);
+
+ err = -EINVAL;
+ if (sock->state != SS_UNCONNECTED || sock->type != SOCK_STREAM)
+ goto unlock;
+
+ ssock = __mptcp_nmpc_socket(msk);
+ if (!ssock) {
+ err = -EINVAL;
+ goto unlock;
+ }
+
+ mptcp_token_destroy(msk);
+ inet_sk_state_store(sk, TCP_LISTEN);
+ sock_set_flag(sk, SOCK_RCU_FREE);
+
+ err = ssock->ops->listen(ssock, backlog);
+ inet_sk_state_store(sk, inet_sk_state_load(ssock->sk));
+ if (!err)
+ mptcp_copy_inaddrs(sk, ssock->sk);
+
+unlock:
+ release_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);
+
+ /* Buggy applications can call accept on socket states other then LISTEN
+ * but no need to allocate the first subflow just to error out.
+ */
+ ssock = READ_ONCE(msk->subflow);
+ if (!ssock)
+ return -EINVAL;
+
+ 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;
+ struct sock *newsk = newsock->sk;
+
+ msk->in_accept_queue = 0;
+
+ lock_sock(newsk);
+
+ /* set ssk->sk_socket of accept()ed flows to mptcp socket.
+ * This is needed so NOSPACE flag can be set from tcp stack.
+ */
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ if (!ssk->sk_socket)
+ mptcp_sock_graft(ssk, newsock);
+ }
+
+ /* Do late cleanup for the first subflow as necessary. Also
+ * deal with bad peers not doing a complete shutdown.
+ */
+ if (msk->first &&
+ unlikely(inet_sk_state_load(msk->first) == TCP_CLOSE)) {
+ __mptcp_close_ssk(newsk, msk->first,
+ mptcp_subflow_ctx(msk->first), 0);
+ if (unlikely(list_empty(&msk->conn_list)))
+ inet_sk_state_store(newsk, TCP_CLOSE);
+ }
+
+ release_sock(newsk);
+ }
+
+ return err;
+}
+
+static __poll_t mptcp_check_writeable(struct mptcp_sock *msk)
+{
+ struct sock *sk = (struct sock *)msk;
+
+ if (sk_stream_is_writeable(sk))
+ return EPOLLOUT | EPOLLWRNORM;
+
+ mptcp_set_nospace(sk);
+ smp_mb__after_atomic(); /* msk->flags is changed by write_space cb */
+ if (sk_stream_is_writeable(sk))
+ return EPOLLOUT | EPOLLWRNORM;
+
+ return 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;
+ u8 shutdown;
+ 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) {
+ struct socket *ssock = READ_ONCE(msk->subflow);
+
+ if (WARN_ON_ONCE(!ssock || !ssock->sk))
+ return 0;
+
+ return inet_csk_listen_poll(ssock->sk);
+ }
+
+ shutdown = READ_ONCE(sk->sk_shutdown);
+ if (shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
+ mask |= EPOLLHUP;
+ if (shutdown & RCV_SHUTDOWN)
+ mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
+
+ if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) {
+ mask |= mptcp_check_readable(msk);
+ if (shutdown & SEND_SHUTDOWN)
+ mask |= EPOLLOUT | EPOLLWRNORM;
+ else
+ mask |= mptcp_check_writeable(msk);
+ } else if (state == TCP_SYN_SENT && inet_sk(sk)->defer_connect) {
+ /* cf tcp_poll() note about TFO */
+ mask |= EPOLLOUT | EPOLLWRNORM;
+ }
+
+ /* This barrier is coupled with smp_wmb() in __mptcp_error_report() */
+ smp_rmb();
+ if (READ_ONCE(sk->sk_err))
+ mask |= EPOLLERR;
+
+ return mask;
+}
+
+static const struct proto_ops mptcp_stream_ops = {
+ .family = PF_INET,
+ .owner = THIS_MODULE,
+ .release = inet_release,
+ .bind = mptcp_bind,
+ .connect = inet_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 = inet_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,
+};
+
+static int mptcp_napi_poll(struct napi_struct *napi, int budget)
+{
+ struct mptcp_delegated_action *delegated;
+ struct mptcp_subflow_context *subflow;
+ int work_done = 0;
+
+ delegated = container_of(napi, struct mptcp_delegated_action, napi);
+ while ((subflow = mptcp_subflow_delegated_next(delegated)) != NULL) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ bh_lock_sock_nested(ssk);
+ if (!sock_owned_by_user(ssk)) {
+ mptcp_subflow_process_delegated(ssk, xchg(&subflow->delegated_status, 0));
+ } else {
+ /* tcp_release_cb_override already processed
+ * the action or will do at next release_sock().
+ * In both case must dequeue the subflow here - on the same
+ * CPU that scheduled it.
+ */
+ smp_wmb();
+ clear_bit(MPTCP_DELEGATE_SCHEDULED, &subflow->delegated_status);
+ }
+ bh_unlock_sock(ssk);
+ sock_put(ssk);
+
+ if (++work_done == budget)
+ return budget;
+ }
+
+ /* always provide a 0 'work_done' argument, so that napi_complete_done
+ * will not try accessing the NULL napi->dev ptr
+ */
+ napi_complete_done(napi, 0);
+ return work_done;
+}
+
+void __init mptcp_proto_init(void)
+{
+ struct mptcp_delegated_action *delegated;
+ int cpu;
+
+ 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");
+
+ init_dummy_netdev(&mptcp_napi_dev);
+ for_each_possible_cpu(cpu) {
+ delegated = per_cpu_ptr(&mptcp_delegated_actions, cpu);
+ INIT_LIST_HEAD(&delegated->head);
+ netif_napi_add_tx(&mptcp_napi_dev, &delegated->napi,
+ mptcp_napi_poll);
+ napi_enable(&delegated->napi);
+ }
+
+ 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 = inet_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 = inet_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 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.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