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813e0a683d
linux-next/net/mptcp/protocol.c
Paolo Abeni 813e0a683d mptcp: try to push pending data on snd una updates 
After the previous patch we may end-up with unsent data
in the write buffer. If such buffer is full, the writer
will block for unlimited time.

We need to trigger the MPTCP xmit path even for the
subflow rx path, on MPTCP snd_una updates.

Keep things simple and just schedule the work queue if
needed.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-11-16 10:46:07 -08:00

2999 lines
73 KiB
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// 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 "protocol.h"
#include "mib.h"
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
struct mptcp6_sock {
struct mptcp_sock msk;
struct ipv6_pinfo np;
};
#endif
struct mptcp_skb_cb {
u64 map_seq;
u64 end_seq;
u32 offset;
};
#define MPTCP_SKB_CB(__skb) ((struct mptcp_skb_cb *)&((__skb)->cb[0]))
static struct percpu_counter mptcp_sockets_allocated;
static void __mptcp_destroy_sock(struct sock *sk);
static void __mptcp_check_send_data_fin(struct sock *sk);
/* If msk has an initial subflow socket, and the MP_CAPABLE handshake has not
* completed yet or has failed, return the subflow socket.
* Otherwise return NULL.
*/
static struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk)
{
if (!msk->subflow || READ_ONCE(msk->can_ack))
return NULL;
return msk->subflow;
}
static bool mptcp_is_tcpsk(struct sock *sk)
{
struct socket *sock = sk->sk_socket;
if (unlikely(sk->sk_prot == &tcp_prot)) {
/* we are being invoked after mptcp_accept() has
* accepted a non-mp-capable flow: sk is a tcp_sk,
* not an mptcp one.
*
* Hand the socket over to tcp so all further socket ops
* bypass mptcp.
*/
sock->ops = &inet_stream_ops;
return true;
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
} else if (unlikely(sk->sk_prot == &tcpv6_prot)) {
sock->ops = &inet6_stream_ops;
return true;
#endif
}
return false;
}
static struct sock *__mptcp_tcp_fallback(struct mptcp_sock *msk)
{
sock_owned_by_me((const struct sock *)msk);
if (likely(!__mptcp_check_fallback(msk)))
return NULL;
return msk->first;
}
static int __mptcp_socket_create(struct mptcp_sock *msk)
{
struct mptcp_subflow_context *subflow;
struct sock *sk = (struct sock *)msk;
struct socket *ssock;
int err;
err = mptcp_subflow_create_socket(sk, &ssock);
if (err)
return err;
msk->first = ssock->sk;
msk->subflow = ssock;
subflow = mptcp_subflow_ctx(ssock->sk);
list_add(&subflow->node, &msk->conn_list);
sock_hold(ssock->sk);
subflow->request_mptcp = 1;
/* accept() will wait on first subflow sk_wq, and we always wakes up
* via msk->sk_socket
*/
RCU_INIT_POINTER(msk->first->sk_wq, &sk->sk_socket->wq);
return 0;
}
static void mptcp_drop(struct sock *sk, struct sk_buff *skb)
{
sk_drops_add(sk, skb);
__kfree_skb(skb);
}
static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to,
struct sk_buff *from)
{
bool fragstolen;
int delta;
if (MPTCP_SKB_CB(from)->offset ||
!skb_try_coalesce(to, from, &fragstolen, &delta))
return false;
pr_debug("colesced seq %llx into %llx new len %d new end seq %llx",
MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq,
to->len, MPTCP_SKB_CB(from)->end_seq);
MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq;
kfree_skb_partial(from, fragstolen);
atomic_add(delta, &sk->sk_rmem_alloc);
sk_mem_charge(sk, delta);
return true;
}
static bool mptcp_ooo_try_coalesce(struct mptcp_sock *msk, struct sk_buff *to,
struct sk_buff *from)
{
if (MPTCP_SKB_CB(from)->map_seq != MPTCP_SKB_CB(to)->end_seq)
return false;
return mptcp_try_coalesce((struct sock *)msk, to, from);
}
/* "inspired" by tcp_data_queue_ofo(), main differences:
* - use mptcp seqs
* - don't cope with sacks
*/
static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb)
{
struct sock *sk = (struct sock *)msk;
struct rb_node **p, *parent;
u64 seq, end_seq, max_seq;
struct sk_buff *skb1;
int space;
seq = MPTCP_SKB_CB(skb)->map_seq;
end_seq = MPTCP_SKB_CB(skb)->end_seq;
space = tcp_space(sk);
max_seq = space > 0 ? space + msk->ack_seq : msk->ack_seq;
pr_debug("msk=%p seq=%llx limit=%llx empty=%d", msk, seq, max_seq,
RB_EMPTY_ROOT(&msk->out_of_order_queue));
if (after64(seq, max_seq)) {
/* out of window */
mptcp_drop(sk, skb);
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_NODSSWINDOW);
return;
}
p = &msk->out_of_order_queue.rb_node;
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUE);
if (RB_EMPTY_ROOT(&msk->out_of_order_queue)) {
rb_link_node(&skb->rbnode, NULL, p);
rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
msk->ooo_last_skb = skb;
goto end;
}
/* with 2 subflows, adding at end of ooo queue is quite likely
* Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup.
*/
if (mptcp_ooo_try_coalesce(msk, msk->ooo_last_skb, skb)) {
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
return;
}
/* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */
if (!before64(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) {
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
parent = &msk->ooo_last_skb->rbnode;
p = &parent->rb_right;
goto insert;
}
/* Find place to insert this segment. Handle overlaps on the way. */
parent = NULL;
while (*p) {
parent = *p;
skb1 = rb_to_skb(parent);
if (before64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
p = &parent->rb_left;
continue;
}
if (before64(seq, MPTCP_SKB_CB(skb1)->end_seq)) {
if (!after64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) {
/* All the bits are present. Drop. */
mptcp_drop(sk, skb);
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
return;
}
if (after64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
/* partial overlap:
* | skb |
* | skb1 |
* continue traversing
*/
} else {
/* skb's seq == skb1's seq and skb covers skb1.
* Replace skb1 with skb.
*/
rb_replace_node(&skb1->rbnode, &skb->rbnode,
&msk->out_of_order_queue);
mptcp_drop(sk, skb1);
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
goto merge_right;
}
} else if (mptcp_ooo_try_coalesce(msk, skb1, skb)) {
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
return;
}
p = &parent->rb_right;
}
insert:
/* Insert segment into RB tree. */
rb_link_node(&skb->rbnode, parent, p);
rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
merge_right:
/* Remove other segments covered by skb. */
while ((skb1 = skb_rb_next(skb)) != NULL) {
if (before64(end_seq, MPTCP_SKB_CB(skb1)->end_seq))
break;
rb_erase(&skb1->rbnode, &msk->out_of_order_queue);
mptcp_drop(sk, skb1);
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
}
/* If there is no skb after us, we are the last_skb ! */
if (!skb1)
msk->ooo_last_skb = skb;
end:
skb_condense(skb);
skb_set_owner_r(skb, sk);
}
static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk,
struct sk_buff *skb, unsigned int offset,
size_t copy_len)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
struct sock *sk = (struct sock *)msk;
struct sk_buff *tail;
__skb_unlink(skb, &ssk->sk_receive_queue);
skb_ext_reset(skb);
skb_orphan(skb);
/* try to fetch required memory from subflow */
if (!sk_rmem_schedule(sk, skb, skb->truesize)) {
if (ssk->sk_forward_alloc < skb->truesize)
goto drop;
__sk_mem_reclaim(ssk, skb->truesize);
if (!sk_rmem_schedule(sk, skb, skb->truesize))
goto drop;
}
/* the skb map_seq accounts for the skb offset:
* mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq
* value
*/
MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow);
MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len;
MPTCP_SKB_CB(skb)->offset = offset;
if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) {
/* in sequence */
WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len);
tail = skb_peek_tail(&sk->sk_receive_queue);
if (tail && mptcp_try_coalesce(sk, tail, skb))
return true;
skb_set_owner_r(skb, sk);
__skb_queue_tail(&sk->sk_receive_queue, skb);
return true;
} else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) {
mptcp_data_queue_ofo(msk, skb);
return false;
}
/* old data, keep it simple and drop the whole pkt, sender
* will retransmit as needed, if needed.
*/
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
drop:
mptcp_drop(sk, skb);
return false;
}
static void mptcp_stop_timer(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
mptcp_sk(sk)->timer_ival = 0;
}
static void mptcp_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 void mptcp_check_data_fin_ack(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
if (__mptcp_check_fallback(msk))
return;
/* Look for an acknowledged DATA_FIN */
if (((1 << sk->sk_state) &
(TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) &&
msk->write_seq == atomic64_read(&msk->snd_una)) {
mptcp_stop_timer(sk);
WRITE_ONCE(msk->snd_data_fin_enable, 0);
switch (sk->sk_state) {
case TCP_FIN_WAIT1:
inet_sk_state_store(sk, TCP_FIN_WAIT2);
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_timeout(const struct sock *sk, const struct sock *ssk)
{
long tout = ssk && inet_csk(ssk)->icsk_pending ?
inet_csk(ssk)->icsk_timeout - jiffies : 0;
if (tout <= 0)
tout = mptcp_sk(sk)->timer_ival;
mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
}
static void mptcp_check_data_fin(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
u64 rcv_data_fin_seq;
if (__mptcp_check_fallback(msk) || !msk->first)
return;
/* Need to ack a DATA_FIN received from a peer while this side
* of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2.
* msk->rcv_data_fin was set when parsing the incoming options
* at the subflow level and the msk lock was not held, so this
* is the first opportunity to act on the DATA_FIN and change
* the msk state.
*
* If we are caught up to the sequence number of the incoming
* DATA_FIN, send the DATA_ACK now and do state transition. If
* not caught up, do nothing and let the recv code send DATA_ACK
* when catching up.
*/
if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) {
struct mptcp_subflow_context *subflow;
WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1);
WRITE_ONCE(msk->rcv_data_fin, 0);
sk->sk_shutdown |= RCV_SHUTDOWN;
smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
set_bit(MPTCP_DATA_READY, &msk->flags);
switch (sk->sk_state) {
case TCP_ESTABLISHED:
inet_sk_state_store(sk, TCP_CLOSE_WAIT);
break;
case TCP_FIN_WAIT1:
inet_sk_state_store(sk, TCP_CLOSING);
break;
case TCP_FIN_WAIT2:
inet_sk_state_store(sk, TCP_CLOSE);
break;
default:
/* Other states not expected */
WARN_ON_ONCE(1);
break;
}
mptcp_set_timeout(sk, NULL);
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
lock_sock(ssk);
tcp_send_ack(ssk);
release_sock(ssk);
}
mptcp_close_wake_up(sk);
}
}
static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
struct sock *ssk,
unsigned int *bytes)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
struct sock *sk = (struct sock *)msk;
unsigned int moved = 0;
bool more_data_avail;
struct tcp_sock *tp;
u32 old_copied_seq;
bool done = false;
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);
old_copied_seq = tp->copied_seq;
do {
u32 map_remaining, offset;
u32 seq = tp->copied_seq;
struct sk_buff *skb;
bool fin;
/* try to move as much data as available */
map_remaining = subflow->map_data_len -
mptcp_subflow_get_map_offset(subflow);
skb = skb_peek(&ssk->sk_receive_queue);
if (!skb) {
/* if no data is found, a racing workqueue/recvmsg
* already processed the new data, stop here or we
* can enter an infinite loop
*/
if (!moved)
done = true;
break;
}
if (__mptcp_check_fallback(msk)) {
/* if we are running under the workqueue, TCP could have
* collapsed skbs between dummy map creation and now
* be sure to adjust the size
*/
map_remaining = skb->len;
subflow->map_data_len = skb->len;
}
offset = seq - TCP_SKB_CB(skb)->seq;
fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
if (fin) {
done = true;
seq++;
}
if (offset < skb->len) {
size_t len = skb->len - offset;
if (tp->urg_data)
done = true;
if (__mptcp_move_skb(msk, ssk, skb, offset, len))
moved += len;
seq += len;
if (WARN_ON_ONCE(map_remaining < len))
break;
} else {
WARN_ON_ONCE(!fin);
sk_eat_skb(ssk, skb);
done = true;
}
WRITE_ONCE(tp->copied_seq, seq);
more_data_avail = mptcp_subflow_data_available(ssk);
if (atomic_read(&sk->sk_rmem_alloc) > sk_rbuf) {
done = true;
break;
}
} while (more_data_avail);
*bytes += moved;
if (tp->copied_seq != old_copied_seq)
tcp_cleanup_rbuf(ssk, 1);
return done;
}
static bool mptcp_ofo_queue(struct mptcp_sock *msk)
{
struct sock *sk = (struct sock *)msk;
struct sk_buff *skb, *tail;
bool moved = false;
struct rb_node *p;
u64 end_seq;
p = rb_first(&msk->out_of_order_queue);
pr_debug("msk=%p empty=%d", msk, RB_EMPTY_ROOT(&msk->out_of_order_queue));
while (p) {
skb = rb_to_skb(p);
if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq))
break;
p = rb_next(p);
rb_erase(&skb->rbnode, &msk->out_of_order_queue);
if (unlikely(!after64(MPTCP_SKB_CB(skb)->end_seq,
msk->ack_seq))) {
mptcp_drop(sk, skb);
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
continue;
}
end_seq = MPTCP_SKB_CB(skb)->end_seq;
tail = skb_peek_tail(&sk->sk_receive_queue);
if (!tail || !mptcp_ooo_try_coalesce(msk, tail, skb)) {
int delta = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq;
/* skip overlapping data, if any */
pr_debug("uncoalesced seq=%llx ack seq=%llx delta=%d",
MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq,
delta);
MPTCP_SKB_CB(skb)->offset += delta;
__skb_queue_tail(&sk->sk_receive_queue, skb);
}
msk->ack_seq = end_seq;
moved = true;
}
return moved;
}
/* In most cases we will be able to lock the mptcp socket. If its already
* owned, we need to defer to the work queue to avoid ABBA deadlock.
*/
static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk)
{
struct sock *sk = (struct sock *)msk;
unsigned int moved = 0;
if (READ_ONCE(sk->sk_lock.owned))
return false;
if (unlikely(!spin_trylock_bh(&sk->sk_lock.slock)))
return false;
/* must re-check after taking the lock */
if (!READ_ONCE(sk->sk_lock.owned)) {
__mptcp_move_skbs_from_subflow(msk, ssk, &moved);
mptcp_ofo_queue(msk);
/* If the moves have caught up with the DATA_FIN sequence number
* it's time to ack the DATA_FIN and change socket state, but
* this is not a good place to change state. Let the workqueue
* do it.
*/
if (mptcp_pending_data_fin(sk, NULL))
mptcp_schedule_work(sk);
}
spin_unlock_bh(&sk->sk_lock.slock);
return moved > 0;
}
void mptcp_data_ready(struct sock *sk, struct sock *ssk)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
struct mptcp_sock *msk = mptcp_sk(sk);
int sk_rbuf, ssk_rbuf;
bool wake;
/* move_skbs_to_msk below can legitly clear the data_avail flag,
* but we will need later to properly woke the reader, cache its
* value
*/
wake = subflow->data_avail == MPTCP_SUBFLOW_DATA_AVAIL;
if (wake)
set_bit(MPTCP_DATA_READY, &msk->flags);
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 */
if (atomic_read(&sk->sk_rmem_alloc) > sk_rbuf)
goto wake;
if (move_skbs_to_msk(msk, ssk))
goto wake;
/* mptcp socket is owned, release_cb should retry */
if (!test_and_set_bit(TCP_DELACK_TIMER_DEFERRED,
&sk->sk_tsq_flags)) {
sock_hold(sk);
/* need to try again, its possible release_cb() has already
* been called after the test_and_set_bit() above.
*/
move_skbs_to_msk(msk, ssk);
}
wake:
if (wake)
sk->sk_data_ready(sk);
}
static void __mptcp_flush_join_list(struct mptcp_sock *msk)
{
if (likely(list_empty(&msk->join_list)))
return;
spin_lock_bh(&msk->join_list_lock);
list_splice_tail_init(&msk->join_list, &msk->conn_list);
spin_unlock_bh(&msk->join_list_lock);
}
static bool mptcp_timer_pending(struct sock *sk)
{
return timer_pending(&inet_csk(sk)->icsk_retransmit_timer);
}
static void mptcp_reset_timer(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
unsigned long tout;
/* prevent rescheduling on close */
if (unlikely(inet_sk_state_load(sk) == TCP_CLOSE))
return;
/* should never be called with mptcp level timer cleared */
tout = READ_ONCE(mptcp_sk(sk)->timer_ival);
if (WARN_ON_ONCE(!tout))
tout = TCP_RTO_MIN;
sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout);
}
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_data_acked(struct sock *sk)
{
mptcp_reset_timer(sk);
if ((!test_bit(MPTCP_SEND_SPACE, &mptcp_sk(sk)->flags) ||
mptcp_send_head(sk) ||
(inet_sk_state_load(sk) != TCP_ESTABLISHED)))
mptcp_schedule_work(sk);
}
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
*/
sk->sk_shutdown |= RCV_SHUTDOWN;
smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
set_bit(MPTCP_DATA_READY, &msk->flags);
sk->sk_data_ready(sk);
}
switch (sk->sk_state) {
case TCP_ESTABLISHED:
inet_sk_state_store(sk, TCP_CLOSE_WAIT);
break;
case TCP_FIN_WAIT1:
/* fallback sockets skip TCP_CLOSING - TCP will take care */
inet_sk_state_store(sk, TCP_CLOSE);
break;
default:
return;
}
mptcp_close_wake_up(sk);
}
static bool mptcp_ext_cache_refill(struct mptcp_sock *msk)
{
const struct sock *sk = (const struct sock *)msk;
if (!msk->cached_ext)
msk->cached_ext = __skb_ext_alloc(sk->sk_allocation);
return !!msk->cached_ext;
}
static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk)
{
struct mptcp_subflow_context *subflow;
struct sock *sk = (struct sock *)msk;
sock_owned_by_me(sk);
mptcp_for_each_subflow(msk, subflow) {
if (subflow->data_avail)
return mptcp_subflow_tcp_sock(subflow);
}
return NULL;
}
static bool mptcp_skb_can_collapse_to(u64 write_seq,
const struct sk_buff *skb,
const struct mptcp_ext *mpext)
{
if (!tcp_skb_can_collapse_to(skb))
return false;
/* can collapse only if MPTCP level sequence is in order and this
* mapping has not been xmitted yet
*/
return mpext && mpext->data_seq + mpext->data_len == write_seq &&
!mpext->frozen;
}
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 &&
df->data_seq + df->data_len == msk->write_seq;
}
static void dfrag_uncharge(struct sock *sk, int len)
{
sk_mem_uncharge(sk, len);
sk_wmem_queued_add(sk, -len);
}
static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag)
{
int len = dfrag->data_len + dfrag->overhead;
list_del(&dfrag->list);
dfrag_uncharge(sk, len);
put_page(dfrag->page);
}
static bool mptcp_is_writeable(struct mptcp_sock *msk)
{
struct mptcp_subflow_context *subflow;
if (!sk_stream_is_writeable((struct sock *)msk))
return false;
mptcp_for_each_subflow(msk, subflow) {
if (sk_stream_is_writeable(subflow->tcp_sock))
return true;
}
return false;
}
static void mptcp_clean_una(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
struct mptcp_data_frag *dtmp, *dfrag;
bool cleaned = false;
u64 snd_una;
/* on fallback we just need to ignore snd_una, as this is really
* plain TCP
*/
if (__mptcp_check_fallback(msk))
atomic64_set(&msk->snd_una, msk->snd_nxt);
snd_una = atomic64_read(&msk->snd_una);
list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) {
if (after64(dfrag->data_seq + dfrag->data_len, snd_una))
break;
if (WARN_ON_ONCE(dfrag == msk->first_pending))
break;
dfrag_clear(sk, dfrag);
cleaned = true;
}
dfrag = mptcp_rtx_head(sk);
if (dfrag && after64(snd_una, dfrag->data_seq)) {
u64 delta = snd_una - dfrag->data_seq;
if (WARN_ON_ONCE(delta > dfrag->already_sent))
goto out;
dfrag->data_seq += delta;
dfrag->offset += delta;
dfrag->data_len -= delta;
dfrag->already_sent -= delta;
dfrag_uncharge(sk, delta);
cleaned = true;
}
out:
if (cleaned)
sk_mem_reclaim_partial(sk);
}
static void mptcp_clean_una_wakeup(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
mptcp_clean_una(sk);
/* Only wake up writers if a subflow is ready */
if (mptcp_is_writeable(msk)) {
set_bit(MPTCP_SEND_SPACE, &msk->flags);
smp_mb__after_atomic();
/* set SEND_SPACE before sk_stream_write_space clears
* NOSPACE
*/
sk_stream_write_space(sk);
}
}
/* ensure we get enough memory for the frag hdr, beyond some minimal amount of
* data
*/
static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag)
{
struct mptcp_subflow_context *subflow;
struct mptcp_sock *msk = mptcp_sk(sk);
bool first = true;
if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag),
pfrag, sk->sk_allocation)))
return 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;
}
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;
};
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;
struct mptcp_sock *msk = mptcp_sk(sk);
struct mptcp_ext *mpext = NULL;
struct sk_buff *skb, *tail;
bool can_collapse = false;
int avail_size;
size_t ret;
pr_debug("msk=%p ssk=%p sending dfrag at seq=%lld len=%d already sent=%d",
msk, ssk, dfrag->data_seq, dfrag->data_len, info->sent);
/* compute send limit */
info->mss_now = tcp_send_mss(ssk, &info->size_goal, info->flags);
avail_size = info->size_goal;
skb = tcp_write_queue_tail(ssk);
if (skb) {
/* 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);
can_collapse = (info->size_goal - skb->len > 0) &&
mptcp_skb_can_collapse_to(data_seq, skb, mpext);
if (!can_collapse)
TCP_SKB_CB(skb)->eor = 1;
else
avail_size = info->size_goal - skb->len;
}
if (WARN_ON_ONCE(info->sent > info->limit ||
info->limit > dfrag->data_len))
return 0;
ret = info->limit - info->sent;
tail = tcp_build_frag(ssk, avail_size, info->flags, dfrag->page,
dfrag->offset + info->sent, &ret);
if (!tail) {
tcp_remove_empty_skb(sk, tcp_write_queue_tail(ssk));
return -ENOMEM;
}
/* if the tail skb is still the cached one, collapsing really happened.
*/
if (skb == tail) {
WARN_ON_ONCE(!can_collapse);
mpext->data_len += ret;
goto out;
}
mpext = __skb_ext_set(tail, SKB_EXT_MPTCP, msk->cached_ext);
msk->cached_ext = NULL;
memset(mpext, 0, sizeof(*mpext));
mpext->data_seq = data_seq;
mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq;
mpext->data_len = ret;
mpext->use_map = 1;
mpext->dsn64 = 1;
pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d",
mpext->data_seq, mpext->subflow_seq, mpext->data_len,
mpext->dsn64);
out:
mptcp_subflow_ctx(ssk)->rel_write_seq += ret;
return ret;
}
static void mptcp_nospace(struct mptcp_sock *msk)
{
struct mptcp_subflow_context *subflow;
clear_bit(MPTCP_SEND_SPACE, &msk->flags);
smp_mb__after_atomic(); /* msk->flags is changed by write_space cb */
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
struct socket *sock = READ_ONCE(ssk->sk_socket);
/* enables ssk->write_space() callbacks */
if (sock)
set_bit(SOCK_NOSPACE, &sock->flags);
}
}
static bool mptcp_subflow_active(struct mptcp_subflow_context *subflow)
{
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
/* can't send if JOIN hasn't completed yet (i.e. is usable for mptcp) */
if (subflow->request_join && !subflow->fully_established)
return false;
/* only send if our side has not closed yet */
return ((1 << ssk->sk_state) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT));
}
#define MPTCP_SEND_BURST_SIZE ((1 << 16) - \
sizeof(struct tcphdr) - \
MAX_TCP_OPTION_SPACE - \
sizeof(struct ipv6hdr) - \
sizeof(struct frag_hdr))
struct subflow_send_info {
struct sock *ssk;
u64 ratio;
};
static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk,
u32 *sndbuf)
{
struct subflow_send_info send_info[2];
struct mptcp_subflow_context *subflow;
int i, nr_active = 0;
struct sock *ssk;
u64 ratio;
u32 pace;
sock_owned_by_me((struct sock *)msk);
*sndbuf = 0;
if (!mptcp_ext_cache_refill(msk))
return NULL;
if (__mptcp_check_fallback(msk)) {
if (!msk->first)
return NULL;
*sndbuf = msk->first->sk_sndbuf;
return sk_stream_memory_free(msk->first) ? msk->first : NULL;
}
/* re-use last subflow, if the burst allow that */
if (msk->last_snd && msk->snd_burst > 0 &&
sk_stream_memory_free(msk->last_snd) &&
mptcp_subflow_active(mptcp_subflow_ctx(msk->last_snd))) {
mptcp_for_each_subflow(msk, subflow) {
ssk = mptcp_subflow_tcp_sock(subflow);
*sndbuf = max(tcp_sk(ssk)->snd_wnd, *sndbuf);
}
return msk->last_snd;
}
/* pick the subflow with the lower wmem/wspace ratio */
for (i = 0; i < 2; ++i) {
send_info[i].ssk = NULL;
send_info[i].ratio = -1;
}
mptcp_for_each_subflow(msk, subflow) {
ssk = mptcp_subflow_tcp_sock(subflow);
if (!mptcp_subflow_active(subflow))
continue;
nr_active += !subflow->backup;
*sndbuf = max(tcp_sk(ssk)->snd_wnd, *sndbuf);
if (!sk_stream_memory_free(subflow->tcp_sock))
continue;
pace = READ_ONCE(ssk->sk_pacing_rate);
if (!pace)
continue;
ratio = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32,
pace);
if (ratio < send_info[subflow->backup].ratio) {
send_info[subflow->backup].ssk = ssk;
send_info[subflow->backup].ratio = ratio;
}
}
pr_debug("msk=%p nr_active=%d ssk=%p:%lld backup=%p:%lld",
msk, nr_active, send_info[0].ssk, send_info[0].ratio,
send_info[1].ssk, send_info[1].ratio);
/* pick the best backup if no other subflow is active */
if (!nr_active)
send_info[0].ssk = send_info[1].ssk;
if (send_info[0].ssk) {
msk->last_snd = send_info[0].ssk;
msk->snd_burst = min_t(int, MPTCP_SEND_BURST_SIZE,
sk_stream_wspace(msk->last_snd));
return msk->last_snd;
}
return NULL;
}
static void ssk_check_wmem(struct mptcp_sock *msk)
{
if (unlikely(!mptcp_is_writeable(msk)))
mptcp_nospace(msk);
}
static void mptcp_push_release(struct sock *sk, struct sock *ssk,
struct mptcp_sendmsg_info *info)
{
mptcp_set_timeout(sk, ssk);
tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal);
release_sock(ssk);
}
static 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,
};
struct mptcp_data_frag *dfrag;
int len, copied = 0;
u32 sndbuf;
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;
__mptcp_flush_join_list(msk);
ssk = mptcp_subflow_get_send(msk, &sndbuf);
/* do auto tuning */
if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK) &&
sndbuf > READ_ONCE(sk->sk_sndbuf))
WRITE_ONCE(sk->sk_sndbuf, sndbuf);
/* try to keep the subflow socket lock across
* consecutive xmit on the same socket
*/
if (ssk != prev_ssk && prev_ssk)
mptcp_push_release(sk, prev_ssk, &info);
if (!ssk)
goto out;
if (ssk != prev_ssk || !prev_ssk)
lock_sock(ssk);
ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
if (ret <= 0) {
mptcp_push_release(sk, ssk, &info);
goto out;
}
info.sent += ret;
dfrag->already_sent += ret;
msk->snd_nxt += ret;
msk->snd_burst -= ret;
copied += ret;
len -= 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(sk, ssk, &info);
out:
/* start the timer, if it's not pending */
if (!mptcp_timer_pending(sk))
mptcp_reset_timer(sk);
if (copied)
__mptcp_check_send_data_fin(sk);
}
static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
{
struct mptcp_sock *msk = mptcp_sk(sk);
struct page_frag *pfrag;
size_t copied = 0;
int ret = 0;
long timeo;
if (msg->msg_flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL))
return -EOPNOTSUPP;
lock_sock(sk);
timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
ret = sk_stream_wait_connect(sk, &timeo);
if (ret)
goto out;
}
pfrag = sk_page_frag(sk);
mptcp_clean_una(sk);
while (msg_data_left(msg)) {
struct mptcp_data_frag *dfrag;
int frag_truesize = 0;
bool dfrag_collapsed;
size_t psize, offset;
if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) {
ret = -EPIPE;
goto out;
}
/* 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)) {
mptcp_push_pending(sk, msg->msg_flags);
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));
if (!sk_wmem_schedule(sk, psize + frag_truesize))
goto wait_for_memory;
if (copy_page_from_iter(dfrag->page, offset, psize,
&msg->msg_iter) != psize) {
ret = -EFAULT;
goto out;
}
/* data successfully copied into the write queue */
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);
sk->sk_forward_alloc -= 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=%lld len=%d sent=%d new=%d", msk,
dfrag->data_seq, dfrag->data_len, dfrag->already_sent,
!dfrag_collapsed);
if (!mptcp_ext_cache_refill(msk))
goto wait_for_memory;
continue;
wait_for_memory:
mptcp_nospace(msk);
mptcp_clean_una(sk);
if (mptcp_timer_pending(sk))
mptcp_reset_timer(sk);
ret = sk_stream_wait_memory(sk, &timeo);
if (ret)
goto out;
}
if (copied)
mptcp_push_pending(sk, msg->msg_flags);
out:
ssk_check_wmem(msk);
release_sock(sk);
return copied ? : ret;
}
static void mptcp_wait_data(struct sock *sk, long *timeo)
{
DEFINE_WAIT_FUNC(wait, woken_wake_function);
struct mptcp_sock *msk = mptcp_sk(sk);
add_wait_queue(sk_sleep(sk), &wait);
sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
sk_wait_event(sk, timeo,
test_and_clear_bit(MPTCP_DATA_READY, &msk->flags), &wait);
sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
remove_wait_queue(sk_sleep(sk), &wait);
}
static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk,
struct msghdr *msg,
size_t len)
{
struct sock *sk = (struct sock *)msk;
struct sk_buff *skb;
int copied = 0;
while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
u32 offset = MPTCP_SKB_CB(skb)->offset;
u32 data_len = skb->len - offset;
u32 count = min_t(size_t, len - copied, data_len);
int err;
err = skb_copy_datagram_msg(skb, offset, msg, count);
if (unlikely(err < 0)) {
if (!copied)
return err;
break;
}
copied += count;
if (count < data_len) {
MPTCP_SKB_CB(skb)->offset += count;
break;
}
__skb_unlink(skb, &sk->sk_receive_queue);
__kfree_skb(skb);
if (copied >= len)
break;
}
return copied;
}
/* receive buffer autotuning. See tcp_rcv_space_adjust for more information.
*
* Only difference: Use highest rtt estimate of the subflows in use.
*/
static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied)
{
struct mptcp_subflow_context *subflow;
struct sock *sk = (struct sock *)msk;
u32 time, advmss = 1;
u64 rtt_us, mstamp;
sock_owned_by_me(sk);
if (copied <= 0)
return;
msk->rcvq_space.copied += copied;
mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC);
time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time);
rtt_us = msk->rcvq_space.rtt_us;
if (rtt_us && time < (rtt_us >> 3))
return;
rtt_us = 0;
mptcp_for_each_subflow(msk, subflow) {
const struct tcp_sock *tp;
u64 sf_rtt_us;
u32 sf_advmss;
tp = tcp_sk(mptcp_subflow_tcp_sock(subflow));
sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us);
sf_advmss = READ_ONCE(tp->advmss);
rtt_us = max(sf_rtt_us, rtt_us);
advmss = max(sf_advmss, advmss);
}
msk->rcvq_space.rtt_us = rtt_us;
if (time < (rtt_us >> 3) || rtt_us == 0)
return;
if (msk->rcvq_space.copied <= msk->rcvq_space.space)
goto new_measure;
if (sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf &&
!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
int rcvmem, rcvbuf;
u64 rcvwin, grow;
rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss;
grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space);
do_div(grow, msk->rcvq_space.space);
rcvwin += (grow << 1);
rcvmem = SKB_TRUESIZE(advmss + MAX_TCP_HEADER);
while (tcp_win_from_space(sk, rcvmem) < advmss)
rcvmem += 128;
do_div(rcvwin, advmss);
rcvbuf = min_t(u64, rcvwin * rcvmem,
sock_net(sk)->ipv4.sysctl_tcp_rmem[2]);
if (rcvbuf > sk->sk_rcvbuf) {
u32 window_clamp;
window_clamp = tcp_win_from_space(sk, rcvbuf);
WRITE_ONCE(sk->sk_rcvbuf, rcvbuf);
/* Make subflows follow along. If we do not do this, we
* get drops at subflow level if skbs can't be moved to
* the mptcp rx queue fast enough (announced rcv_win can
* exceed ssk->sk_rcvbuf).
*/
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk;
bool slow;
ssk = mptcp_subflow_tcp_sock(subflow);
slow = lock_sock_fast(ssk);
WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf);
tcp_sk(ssk)->window_clamp = window_clamp;
tcp_cleanup_rbuf(ssk, 1);
unlock_sock_fast(ssk, slow);
}
}
}
msk->rcvq_space.space = msk->rcvq_space.copied;
new_measure:
msk->rcvq_space.copied = 0;
msk->rcvq_space.time = mstamp;
}
static bool __mptcp_move_skbs(struct mptcp_sock *msk)
{
unsigned int moved = 0;
bool done;
/* avoid looping forever below on racing close */
if (((struct sock *)msk)->sk_state == TCP_CLOSE)
return false;
__mptcp_flush_join_list(msk);
do {
struct sock *ssk = mptcp_subflow_recv_lookup(msk);
bool slowpath;
if (!ssk)
break;
slowpath = lock_sock_fast(ssk);
done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
unlock_sock_fast(ssk, slowpath);
} while (!done);
if (mptcp_ofo_queue(msk) || moved > 0) {
mptcp_check_data_fin((struct sock *)msk);
return true;
}
return false;
}
static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
int nonblock, int flags, int *addr_len)
{
struct mptcp_sock *msk = mptcp_sk(sk);
int copied = 0;
int target;
long timeo;
if (msg->msg_flags & ~(MSG_WAITALL | MSG_DONTWAIT))
return -EOPNOTSUPP;
lock_sock(sk);
timeo = sock_rcvtimeo(sk, nonblock);
len = min_t(size_t, len, INT_MAX);
target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
__mptcp_flush_join_list(msk);
while (len > (size_t)copied) {
int bytes_read;
bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied);
if (unlikely(bytes_read < 0)) {
if (!copied)
copied = bytes_read;
goto out_err;
}
copied += bytes_read;
if (skb_queue_empty(&sk->sk_receive_queue) &&
__mptcp_move_skbs(msk))
continue;
/* only the master socket status is relevant here. The exit
* conditions mirror closely tcp_recvmsg()
*/
if (copied >= target)
break;
if (copied) {
if (sk->sk_err ||
sk->sk_state == TCP_CLOSE ||
(sk->sk_shutdown & RCV_SHUTDOWN) ||
!timeo ||
signal_pending(current))
break;
} else {
if (sk->sk_err) {
copied = sock_error(sk);
break;
}
if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
mptcp_check_for_eof(msk);
if (sk->sk_shutdown & RCV_SHUTDOWN)
break;
if (sk->sk_state == TCP_CLOSE) {
copied = -ENOTCONN;
break;
}
if (!timeo) {
copied = -EAGAIN;
break;
}
if (signal_pending(current)) {
copied = sock_intr_errno(timeo);
break;
}
}
pr_debug("block timeout %ld", timeo);
mptcp_wait_data(sk, &timeo);
}
if (skb_queue_empty(&sk->sk_receive_queue)) {
/* entire backlog drained, clear DATA_READY. */
clear_bit(MPTCP_DATA_READY, &msk->flags);
/* .. race-breaker: ssk might have gotten new data
* after last __mptcp_move_skbs() returned false.
*/
if (unlikely(__mptcp_move_skbs(msk)))
set_bit(MPTCP_DATA_READY, &msk->flags);
} else if (unlikely(!test_bit(MPTCP_DATA_READY, &msk->flags))) {
/* data to read but mptcp_wait_data() cleared DATA_READY */
set_bit(MPTCP_DATA_READY, &msk->flags);
}
out_err:
pr_debug("msk=%p data_ready=%d rx queue empty=%d copied=%d",
msk, test_bit(MPTCP_DATA_READY, &msk->flags),
skb_queue_empty(&sk->sk_receive_queue), copied);
mptcp_rcv_space_adjust(msk, copied);
release_sock(sk);
return copied;
}
static void mptcp_retransmit_handler(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
if (atomic64_read(&msk->snd_una) == READ_ONCE(msk->snd_nxt)) {
mptcp_stop_timer(sk);
} else {
set_bit(MPTCP_WORK_RTX, &msk->flags);
mptcp_schedule_work(sk);
}
}
static void mptcp_retransmit_timer(struct timer_list *t)
{
struct inet_connection_sock *icsk = from_timer(icsk, t,
icsk_retransmit_timer);
struct sock *sk = &icsk->icsk_inet.sk;
bh_lock_sock(sk);
if (!sock_owned_by_user(sk)) {
mptcp_retransmit_handler(sk);
} else {
/* delegate our work to tcp_release_cb() */
if (!test_and_set_bit(TCP_WRITE_TIMER_DEFERRED,
&sk->sk_tsq_flags))
sock_hold(sk);
}
bh_unlock_sock(sk);
sock_put(sk);
}
static void mptcp_timeout_timer(struct timer_list *t)
{
struct sock *sk = from_timer(sk, t, sk_timer);
mptcp_schedule_work(sk);
}
/* Find an idle subflow. Return NULL if there is unacked data at tcp
* level.
*
* A backup subflow is returned only if that is the only kind available.
*/
static struct sock *mptcp_subflow_get_retrans(const struct mptcp_sock *msk)
{
struct mptcp_subflow_context *subflow;
struct sock *backup = NULL;
sock_owned_by_me((const struct sock *)msk);
if (__mptcp_check_fallback(msk))
return 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? Don't retransmit. */
if (!tcp_write_queue_empty(ssk))
return NULL;
if (subflow->backup) {
if (!backup)
backup = ssk;
continue;
}
return ssk;
}
return backup;
}
/* subflow sockets can be either outgoing (connect) or incoming
* (accept).
*
* Outgoing subflows use in-kernel sockets.
* Incoming subflows do not have their own 'struct socket' allocated,
* so we need to use tcp_close() after detaching them from the mptcp
* parent socket.
*/
void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
struct mptcp_subflow_context *subflow)
{
bool dispose_socket = false;
struct socket *sock;
list_del(&subflow->node);
lock_sock(ssk);
/* if we are invoked by the msk cleanup code, the subflow is
* already orphaned
*/
sock = ssk->sk_socket;
if (sock) {
dispose_socket = sock != sk->sk_socket;
sock_orphan(ssk);
}
/* 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) {
kfree_rcu(subflow, rcu);
} else {
/* otherwise ask tcp do dispose of ssk and subflow ctx */
subflow->disposable = 1;
__tcp_close(ssk, 0);
/* close acquired an extra ref */
__sock_put(ssk);
}
release_sock(ssk);
if (dispose_socket)
iput(SOCK_INODE(sock));
sock_put(ssk);
}
static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu)
{
return 0;
}
static void pm_work(struct mptcp_sock *msk)
{
struct mptcp_pm_data *pm = &msk->pm;
spin_lock_bh(&msk->pm.lock);
pr_debug("msk=%p status=%x", msk, pm->status);
if (pm->status & BIT(MPTCP_PM_ADD_ADDR_RECEIVED)) {
pm->status &= ~BIT(MPTCP_PM_ADD_ADDR_RECEIVED);
mptcp_pm_nl_add_addr_received(msk);
}
if (pm->status & BIT(MPTCP_PM_RM_ADDR_RECEIVED)) {
pm->status &= ~BIT(MPTCP_PM_RM_ADDR_RECEIVED);
mptcp_pm_nl_rm_addr_received(msk);
}
if (pm->status & BIT(MPTCP_PM_ESTABLISHED)) {
pm->status &= ~BIT(MPTCP_PM_ESTABLISHED);
mptcp_pm_nl_fully_established(msk);
}
if (pm->status & BIT(MPTCP_PM_SUBFLOW_ESTABLISHED)) {
pm->status &= ~BIT(MPTCP_PM_SUBFLOW_ESTABLISHED);
mptcp_pm_nl_subflow_established(msk);
}
spin_unlock_bh(&msk->pm.lock);
}
static void __mptcp_close_subflow(struct mptcp_sock *msk)
{
struct mptcp_subflow_context *subflow, *tmp;
list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
if (inet_sk_state_load(ssk) != TCP_CLOSE)
continue;
__mptcp_close_ssk((struct sock *)msk, ssk, subflow);
}
}
static bool mptcp_check_close_timeout(const struct sock *sk)
{
s32 delta = tcp_jiffies32 - inet_csk(sk)->icsk_mtup.probe_timestamp;
struct mptcp_subflow_context *subflow;
if (delta >= TCP_TIMEWAIT_LEN)
return true;
/* if all subflows are in closed status don't bother with additional
* timeout
*/
mptcp_for_each_subflow(mptcp_sk(sk), subflow) {
if (inet_sk_state_load(mptcp_subflow_tcp_sock(subflow)) !=
TCP_CLOSE)
return false;
}
return true;
}
static void mptcp_worker(struct work_struct *work)
{
struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
struct sock *ssk, *sk = &msk->sk.icsk_inet.sk;
struct mptcp_sendmsg_info info = {};
struct mptcp_data_frag *dfrag;
size_t copied = 0;
int state, ret;
lock_sock(sk);
set_bit(MPTCP_WORKER_RUNNING, &msk->flags);
state = sk->sk_state;
if (unlikely(state == TCP_CLOSE))
goto unlock;
mptcp_clean_una_wakeup(sk);
mptcp_check_data_fin_ack(sk);
__mptcp_flush_join_list(msk);
if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
__mptcp_close_subflow(msk);
__mptcp_move_skbs(msk);
if (mptcp_send_head(sk))
mptcp_push_pending(sk, 0);
if (msk->pm.status)
pm_work(msk);
if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
mptcp_check_for_eof(msk);
mptcp_check_data_fin(sk);
/* if the msk data is completely acked, or the socket timedout,
* there is no point in keeping around an orphaned sk
*/
if (sock_flag(sk, SOCK_DEAD) &&
(mptcp_check_close_timeout(sk) ||
(state != sk->sk_state &&
((1 << inet_sk_state_load(sk)) & (TCPF_CLOSE | TCPF_FIN_WAIT2))))) {
inet_sk_state_store(sk, TCP_CLOSE);
__mptcp_destroy_sock(sk);
goto unlock;
}
if (!test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
goto unlock;
dfrag = mptcp_rtx_head(sk);
if (!dfrag)
goto unlock;
if (!mptcp_ext_cache_refill(msk))
goto reset_unlock;
ssk = mptcp_subflow_get_retrans(msk);
if (!ssk)
goto reset_unlock;
lock_sock(ssk);
/* limit retransmission to the bytes already sent on some subflows */
info.sent = 0;
info.limit = dfrag->already_sent;
while (info.sent < dfrag->already_sent) {
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 (!mptcp_ext_cache_refill(msk))
break;
}
if (copied)
tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle,
info.size_goal);
mptcp_set_timeout(sk, ssk);
release_sock(ssk);
reset_unlock:
if (!mptcp_timer_pending(sk))
mptcp_reset_timer(sk);
unlock:
clear_bit(MPTCP_WORKER_RUNNING, &msk->flags);
release_sock(sk);
sock_put(sk);
}
static int __mptcp_init_sock(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
spin_lock_init(&msk->join_list_lock);
INIT_LIST_HEAD(&msk->conn_list);
INIT_LIST_HEAD(&msk->join_list);
INIT_LIST_HEAD(&msk->rtx_queue);
__set_bit(MPTCP_SEND_SPACE, &msk->flags);
INIT_WORK(&msk->work, mptcp_worker);
msk->out_of_order_queue = RB_ROOT;
msk->first_pending = NULL;
msk->first = NULL;
inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss;
mptcp_pm_data_init(msk);
/* re-use the csk retrans timer for MPTCP-level retrans */
timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0);
timer_setup(&sk->sk_timer, mptcp_timeout_timer, 0);
return 0;
}
static int mptcp_init_sock(struct sock *sk)
{
struct net *net = sock_net(sk);
int ret;
ret = __mptcp_init_sock(sk);
if (ret)
return ret;
if (!mptcp_is_enabled(net))
return -ENOPROTOOPT;
if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net))
return -ENOMEM;
ret = __mptcp_socket_create(mptcp_sk(sk));
if (ret)
return ret;
sk_sockets_allocated_inc(sk);
sk->sk_rcvbuf = sock_net(sk)->ipv4.sysctl_tcp_rmem[1];
sk->sk_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[1];
return 0;
}
static void __mptcp_clear_xmit(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
struct mptcp_data_frag *dtmp, *dfrag;
sk_stop_timer(sk, &msk->sk.icsk_retransmit_timer);
WRITE_ONCE(msk->first_pending, NULL);
list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list)
dfrag_clear(sk, dfrag);
}
static void mptcp_cancel_work(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
/* if called by the work itself, do not try to cancel the work, or
* we will hang.
*/
if (!test_bit(MPTCP_WORKER_RUNNING, &msk->flags) &&
cancel_work_sync(&msk->work))
__sock_put(sk);
}
void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how)
{
lock_sock(ssk);
switch (ssk->sk_state) {
case TCP_LISTEN:
if (!(how & RCV_SHUTDOWN))
break;
fallthrough;
case TCP_SYN_SENT:
tcp_disconnect(ssk, O_NONBLOCK);
break;
default:
if (__mptcp_check_fallback(mptcp_sk(sk))) {
pr_debug("Fallback");
ssk->sk_shutdown |= how;
tcp_shutdown(ssk, how);
} else {
pr_debug("Sending DATA_FIN on subflow %p", ssk);
mptcp_set_timeout(sk, ssk);
tcp_send_ack(ssk);
}
break;
}
release_sock(ssk);
}
static const unsigned char new_state[16] = {
/* current state: new state: action: */
[0 /* (Invalid) */] = TCP_CLOSE,
[TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
[TCP_SYN_SENT] = TCP_CLOSE,
[TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
[TCP_FIN_WAIT1] = TCP_FIN_WAIT1,
[TCP_FIN_WAIT2] = TCP_FIN_WAIT2,
[TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */
[TCP_CLOSE] = TCP_CLOSE,
[TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN,
[TCP_LAST_ACK] = TCP_LAST_ACK,
[TCP_LISTEN] = TCP_CLOSE,
[TCP_CLOSING] = TCP_CLOSING,
[TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */
};
static int mptcp_close_state(struct sock *sk)
{
int next = (int)new_state[sk->sk_state];
int ns = next & TCP_STATE_MASK;
inet_sk_state_store(sk, ns);
return next & TCP_ACTION_FIN;
}
static void __mptcp_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);
/* fallback socket will not get data_fin/ack, can move to close now */
if (__mptcp_check_fallback(msk) && sk->sk_state == TCP_LAST_ACK) {
inet_sk_state_store(sk, TCP_CLOSE);
mptcp_close_wake_up(sk);
}
__mptcp_flush_join_list(msk);
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_subflow_context *subflow, *tmp;
struct mptcp_sock *msk = mptcp_sk(sk);
LIST_HEAD(conn_list);
pr_debug("msk=%p", msk);
/* be sure to always acquire the join list lock, to sync vs
* mptcp_finish_join().
*/
spin_lock_bh(&msk->join_list_lock);
list_splice_tail_init(&msk->join_list, &msk->conn_list);
spin_unlock_bh(&msk->join_list_lock);
list_splice_init(&msk->conn_list, &conn_list);
__mptcp_clear_xmit(sk);
sk_stop_timer(sk, &sk->sk_timer);
msk->pm.status = 0;
list_for_each_entry_safe(subflow, tmp, &conn_list, node) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
__mptcp_close_ssk(sk, ssk, subflow);
}
sk->sk_prot->destroy(sk);
sk_stream_kill_queues(sk);
xfrm_sk_free_policy(sk);
sk_refcnt_debug_release(sk);
sock_put(sk);
}
static void mptcp_close(struct sock *sk, long timeout)
{
struct mptcp_subflow_context *subflow;
bool do_cancel_work = false;
lock_sock(sk);
sk->sk_shutdown = SHUTDOWN_MASK;
if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) {
inet_sk_state_store(sk, TCP_CLOSE);
goto cleanup;
}
if (mptcp_close_state(sk))
__mptcp_wr_shutdown(sk);
sk_stream_wait_close(sk, timeout);
cleanup:
/* orphan all the subflows */
inet_csk(sk)->icsk_mtup.probe_timestamp = tcp_jiffies32;
list_for_each_entry(subflow, &mptcp_sk(sk)->conn_list, node) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
bool slow, dispose_socket;
struct socket *sock;
slow = lock_sock_fast(ssk);
sock = ssk->sk_socket;
dispose_socket = sock && sock != sk->sk_socket;
sock_orphan(ssk);
unlock_sock_fast(ssk, slow);
/* for the outgoing subflows we additionally need to free
* the associated socket
*/
if (dispose_socket)
iput(SOCK_INODE(sock));
}
sock_orphan(sk);
sock_hold(sk);
pr_debug("msk=%p state=%d", sk, sk->sk_state);
if (sk->sk_state == TCP_CLOSE) {
__mptcp_destroy_sock(sk);
do_cancel_work = true;
} else {
sk_reset_timer(sk, &sk->sk_timer, jiffies + TCP_TIMEWAIT_LEN);
}
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)
{
/* Should never be called.
* inet_stream_connect() calls ->disconnect, but that
* refers to the subflow socket, not the mptcp one.
*/
WARN_ON_ONCE(1);
return 0;
}
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk)
{
unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo);
return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
}
#endif
struct sock *mptcp_sk_clone(const struct sock *sk,
const struct mptcp_options_received *mp_opt,
struct request_sock *req)
{
struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC);
struct mptcp_sock *msk;
u64 ack_seq;
if (!nsk)
return NULL;
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
if (nsk->sk_family == AF_INET6)
inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk);
#endif
__mptcp_init_sock(nsk);
msk = mptcp_sk(nsk);
msk->local_key = subflow_req->local_key;
msk->token = subflow_req->token;
msk->subflow = NULL;
WRITE_ONCE(msk->fully_established, false);
msk->write_seq = subflow_req->idsn + 1;
msk->snd_nxt = msk->write_seq;
atomic64_set(&msk->snd_una, msk->write_seq);
if (mp_opt->mp_capable) {
msk->can_ack = true;
msk->remote_key = mp_opt->sndr_key;
mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq);
ack_seq++;
WRITE_ONCE(msk->ack_seq, ack_seq);
}
sock_reset_flag(nsk, SOCK_RCU_FREE);
/* will be fully established after successful MPC subflow creation */
inet_sk_state_store(nsk, TCP_SYN_RECV);
bh_unlock_sock(nsk);
/* keep a single reference */
__sock_put(nsk);
return nsk;
}
void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk)
{
const struct tcp_sock *tp = tcp_sk(ssk);
msk->rcvq_space.copied = 0;
msk->rcvq_space.rtt_us = 0;
msk->rcvq_space.time = tp->tcp_mstamp;
/* initial rcv_space offering made to peer */
msk->rcvq_space.space = min_t(u32, tp->rcv_wnd,
TCP_INIT_CWND * tp->advmss);
if (msk->rcvq_space.space == 0)
msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT;
}
static struct sock *mptcp_accept(struct sock *sk, int flags, int *err,
bool kern)
{
struct mptcp_sock *msk = mptcp_sk(sk);
struct socket *listener;
struct sock *newsk;
listener = __mptcp_nmpc_socket(msk);
if (WARN_ON_ONCE(!listener)) {
*err = -EINVAL;
return NULL;
}
pr_debug("msk=%p, listener=%p", msk, mptcp_subflow_ctx(listener->sk));
newsk = inet_csk_accept(listener->sk, flags, err, kern);
if (!newsk)
return NULL;
pr_debug("msk=%p, subflow is mptcp=%d", msk, sk_is_mptcp(newsk));
if (sk_is_mptcp(newsk)) {
struct mptcp_subflow_context *subflow;
struct sock *new_mptcp_sock;
struct sock *ssk = newsk;
subflow = mptcp_subflow_ctx(newsk);
new_mptcp_sock = subflow->conn;
/* is_mptcp should be false if subflow->conn is missing, see
* subflow_syn_recv_sock()
*/
if (WARN_ON_ONCE(!new_mptcp_sock)) {
tcp_sk(newsk)->is_mptcp = 0;
return newsk;
}
/* acquire the 2nd reference for the owning socket */
sock_hold(new_mptcp_sock);
local_bh_disable();
bh_lock_sock(new_mptcp_sock);
msk = mptcp_sk(new_mptcp_sock);
msk->first = newsk;
newsk = new_mptcp_sock;
mptcp_copy_inaddrs(newsk, ssk);
list_add(&subflow->node, &msk->conn_list);
sock_hold(ssk);
mptcp_rcv_space_init(msk, ssk);
bh_unlock_sock(new_mptcp_sock);
__MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEPASSIVEACK);
local_bh_enable();
} else {
MPTCP_INC_STATS(sock_net(sk),
MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK);
}
return newsk;
}
void mptcp_destroy_common(struct mptcp_sock *msk)
{
skb_rbtree_purge(&msk->out_of_order_queue);
mptcp_token_destroy(msk);
mptcp_pm_free_anno_list(msk);
}
static void mptcp_destroy(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
if (msk->cached_ext)
__skb_ext_put(msk->cached_ext);
mptcp_destroy_common(msk);
sk_sockets_allocated_dec(sk);
}
static int mptcp_setsockopt_sol_socket(struct mptcp_sock *msk, int optname,
sockptr_t optval, unsigned int optlen)
{
struct sock *sk = (struct sock *)msk;
struct socket *ssock;
int ret;
switch (optname) {
case SO_REUSEPORT:
case SO_REUSEADDR:
lock_sock(sk);
ssock = __mptcp_nmpc_socket(msk);
if (!ssock) {
release_sock(sk);
return -EINVAL;
}
ret = sock_setsockopt(ssock, SOL_SOCKET, optname, optval, optlen);
if (ret == 0) {
if (optname == SO_REUSEPORT)
sk->sk_reuseport = ssock->sk->sk_reuseport;
else if (optname == SO_REUSEADDR)
sk->sk_reuse = ssock->sk->sk_reuse;
}
release_sock(sk);
return ret;
}
return sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname, optval, optlen);
}
static int mptcp_setsockopt_v6(struct mptcp_sock *msk, int optname,
sockptr_t optval, unsigned int optlen)
{
struct sock *sk = (struct sock *)msk;
int ret = -EOPNOTSUPP;
struct socket *ssock;
switch (optname) {
case IPV6_V6ONLY:
lock_sock(sk);
ssock = __mptcp_nmpc_socket(msk);
if (!ssock) {
release_sock(sk);
return -EINVAL;
}
ret = tcp_setsockopt(ssock->sk, SOL_IPV6, optname, optval, optlen);
if (ret == 0)
sk->sk_ipv6only = ssock->sk->sk_ipv6only;
release_sock(sk);
break;
}
return ret;
}
static int mptcp_setsockopt(struct sock *sk, int level, int optname,
sockptr_t optval, unsigned int optlen)
{
struct mptcp_sock *msk = mptcp_sk(sk);
struct sock *ssk;
pr_debug("msk=%p", msk);
if (level == SOL_SOCKET)
return mptcp_setsockopt_sol_socket(msk, optname, optval, optlen);
/* @@ the meaning of setsockopt() when the socket is connected and
* there are multiple subflows is not yet defined. It is up to the
* MPTCP-level socket to configure the subflows until the subflow
* is in TCP fallback, when TCP socket options are passed through
* to the one remaining subflow.
*/
lock_sock(sk);
ssk = __mptcp_tcp_fallback(msk);
release_sock(sk);
if (ssk)
return tcp_setsockopt(ssk, level, optname, optval, optlen);
if (level == SOL_IPV6)
return mptcp_setsockopt_v6(msk, optname, optval, optlen);
return -EOPNOTSUPP;
}
static int mptcp_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *option)
{
struct mptcp_sock *msk = mptcp_sk(sk);
struct sock *ssk;
pr_debug("msk=%p", msk);
/* @@ the meaning of setsockopt() when the socket is connected and
* there are multiple subflows is not yet defined. It is up to the
* MPTCP-level socket to configure the subflows until the subflow
* is in TCP fallback, when socket options are passed through
* to the one remaining subflow.
*/
lock_sock(sk);
ssk = __mptcp_tcp_fallback(msk);
release_sock(sk);
if (ssk)
return tcp_getsockopt(ssk, level, optname, optval, option);
return -EOPNOTSUPP;
}
#define MPTCP_DEFERRED_ALL (TCPF_DELACK_TIMER_DEFERRED | \
TCPF_WRITE_TIMER_DEFERRED)
/* this is very alike tcp_release_cb() but we must handle differently a
* different set of events
*/
static void mptcp_release_cb(struct sock *sk)
{
unsigned long flags, nflags;
do {
flags = sk->sk_tsq_flags;
if (!(flags & MPTCP_DEFERRED_ALL))
return;
nflags = flags & ~MPTCP_DEFERRED_ALL;
} while (cmpxchg(&sk->sk_tsq_flags, flags, nflags) != flags);
sock_release_ownership(sk);
if (flags & TCPF_DELACK_TIMER_DEFERRED) {
struct mptcp_sock *msk = mptcp_sk(sk);
struct sock *ssk;
ssk = mptcp_subflow_recv_lookup(msk);
if (!ssk || sk->sk_state == TCP_CLOSE ||
!schedule_work(&msk->work))
__sock_put(sk);
}
if (flags & TCPF_WRITE_TIMER_DEFERRED) {
mptcp_retransmit_handler(sk);
__sock_put(sk);
}
}
static int mptcp_hash(struct sock *sk)
{
/* should never be called,
* we hash the TCP subflows not the master socket
*/
WARN_ON_ONCE(1);
return 0;
}
static void mptcp_unhash(struct sock *sk)
{
/* called from sk_common_release(), but nothing to do here */
}
static int mptcp_get_port(struct sock *sk, unsigned short snum)
{
struct mptcp_sock *msk = mptcp_sk(sk);
struct socket *ssock;
ssock = __mptcp_nmpc_socket(msk);
pr_debug("msk=%p, subflow=%p", msk, ssock);
if (WARN_ON_ONCE(!ssock))
return -EINVAL;
return inet_csk_get_port(ssock->sk, snum);
}
void mptcp_finish_connect(struct sock *ssk)
{
struct mptcp_subflow_context *subflow;
struct mptcp_sock *msk;
struct sock *sk;
u64 ack_seq;
subflow = mptcp_subflow_ctx(ssk);
sk = subflow->conn;
msk = mptcp_sk(sk);
pr_debug("msk=%p, token=%u", sk, subflow->token);
mptcp_crypto_key_sha(subflow->remote_key, NULL, &ack_seq);
ack_seq++;
subflow->map_seq = ack_seq;
subflow->map_subflow_seq = 1;
/* the socket is not connected yet, no msk/subflow ops can access/race
* accessing the field below
*/
WRITE_ONCE(msk->remote_key, subflow->remote_key);
WRITE_ONCE(msk->local_key, subflow->local_key);
WRITE_ONCE(msk->write_seq, subflow->idsn + 1);
WRITE_ONCE(msk->snd_nxt, msk->write_seq);
WRITE_ONCE(msk->ack_seq, ack_seq);
WRITE_ONCE(msk->can_ack, 1);
atomic64_set(&msk->snd_una, msk->write_seq);
mptcp_pm_new_connection(msk, 0);
mptcp_rcv_space_init(msk, ssk);
}
static void mptcp_sock_graft(struct sock *sk, struct socket *parent)
{
write_lock_bh(&sk->sk_callback_lock);
rcu_assign_pointer(sk->sk_wq, &parent->wq);
sk_set_socket(sk, parent);
sk->sk_uid = SOCK_INODE(parent)->i_uid;
write_unlock_bh(&sk->sk_callback_lock);
}
bool mptcp_finish_join(struct sock *ssk)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
struct mptcp_sock *msk = mptcp_sk(subflow->conn);
struct sock *parent = (void *)msk;
struct socket *parent_sock;
bool ret;
pr_debug("msk=%p, subflow=%p", msk, subflow);
/* mptcp socket already closing? */
if (!mptcp_is_fully_established(parent))
return false;
if (!msk->pm.server_side)
return true;
if (!mptcp_pm_allow_new_subflow(msk))
return false;
/* active connections are already on conn_list, and we can't acquire
* msk lock here.
* use the join list lock as synchronization point and double-check
* msk status to avoid racing with __mptcp_destroy_sock()
*/
spin_lock_bh(&msk->join_list_lock);
ret = inet_sk_state_load(parent) == TCP_ESTABLISHED;
if (ret && !WARN_ON_ONCE(!list_empty(&subflow->node))) {
list_add_tail(&subflow->node, &msk->join_list);
sock_hold(ssk);
}
spin_unlock_bh(&msk->join_list_lock);
if (!ret)
return false;
/* attach to msk socket only after we are sure he will deal with us
* at close time
*/
parent_sock = READ_ONCE(parent->sk_socket);
if (parent_sock && !ssk->sk_socket)
mptcp_sock_graft(ssk, parent_sock);
subflow->map_seq = READ_ONCE(msk->ack_seq);
return true;
}
static bool mptcp_memory_free(const struct sock *sk, int wake)
{
struct mptcp_sock *msk = mptcp_sk(sk);
return wake ? test_bit(MPTCP_SEND_SPACE, &msk->flags) : true;
}
static struct proto mptcp_prot = {
.name = "MPTCP",
.owner = THIS_MODULE,
.init = mptcp_init_sock,
.disconnect = mptcp_disconnect,
.close = mptcp_close,
.accept = mptcp_accept,
.setsockopt = mptcp_setsockopt,
.getsockopt = mptcp_getsockopt,
.shutdown = tcp_shutdown,
.destroy = mptcp_destroy,
.sendmsg = mptcp_sendmsg,
.recvmsg = mptcp_recvmsg,
.release_cb = mptcp_release_cb,
.hash = mptcp_hash,
.unhash = mptcp_unhash,
.get_port = mptcp_get_port,
.sockets_allocated = &mptcp_sockets_allocated,
.memory_allocated = &tcp_memory_allocated,
.memory_pressure = &tcp_memory_pressure,
.stream_memory_free = mptcp_memory_free,
.sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
.sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
.sysctl_mem = sysctl_tcp_mem,
.obj_size = sizeof(struct mptcp_sock),
.slab_flags = SLAB_TYPESAFE_BY_RCU,
.no_autobind = true,
};
static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
struct mptcp_sock *msk = mptcp_sk(sock->sk);
struct socket *ssock;
int err;
lock_sock(sock->sk);
ssock = __mptcp_nmpc_socket(msk);
if (!ssock) {
err = -EINVAL;
goto unlock;
}
err = ssock->ops->bind(ssock, uaddr, addr_len);
if (!err)
mptcp_copy_inaddrs(sock->sk, ssock->sk);
unlock:
release_sock(sock->sk);
return err;
}
static void mptcp_subflow_early_fallback(struct mptcp_sock *msk,
struct mptcp_subflow_context *subflow)
{
subflow->request_mptcp = 0;
__mptcp_do_fallback(msk);
}
static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
int addr_len, int flags)
{
struct mptcp_sock *msk = mptcp_sk(sock->sk);
struct mptcp_subflow_context *subflow;
struct socket *ssock;
int err;
lock_sock(sock->sk);
if (sock->state != SS_UNCONNECTED && msk->subflow) {
/* pending connection or invalid state, let existing subflow
* cope with that
*/
ssock = msk->subflow;
goto do_connect;
}
ssock = __mptcp_nmpc_socket(msk);
if (!ssock) {
err = -EINVAL;
goto unlock;
}
mptcp_token_destroy(msk);
inet_sk_state_store(sock->sk, TCP_SYN_SENT);
subflow = mptcp_subflow_ctx(ssock->sk);
#ifdef CONFIG_TCP_MD5SIG
/* no MPTCP if MD5SIG is enabled on this socket or we may run out of
* TCP option space.
*/
if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info))
mptcp_subflow_early_fallback(msk, subflow);
#endif
if (subflow->request_mptcp && mptcp_token_new_connect(ssock->sk))
mptcp_subflow_early_fallback(msk, subflow);
do_connect:
err = ssock->ops->connect(ssock, uaddr, addr_len, flags);
sock->state = ssock->state;
/* on successful connect, the msk state will be moved to established by
* subflow_finish_connect()
*/
if (!err || err == -EINPROGRESS)
mptcp_copy_inaddrs(sock->sk, ssock->sk);
else
inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
unlock:
release_sock(sock->sk);
return err;
}
static int mptcp_listen(struct socket *sock, int backlog)
{
struct mptcp_sock *msk = mptcp_sk(sock->sk);
struct socket *ssock;
int err;
pr_debug("msk=%p", msk);
lock_sock(sock->sk);
ssock = __mptcp_nmpc_socket(msk);
if (!ssock) {
err = -EINVAL;
goto unlock;
}
mptcp_token_destroy(msk);
inet_sk_state_store(sock->sk, TCP_LISTEN);
sock_set_flag(sock->sk, SOCK_RCU_FREE);
err = ssock->ops->listen(ssock, backlog);
inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
if (!err)
mptcp_copy_inaddrs(sock->sk, ssock->sk);
unlock:
release_sock(sock->sk);
return err;
}
static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
int flags, bool kern)
{
struct mptcp_sock *msk = mptcp_sk(sock->sk);
struct socket *ssock;
int err;
pr_debug("msk=%p", msk);
lock_sock(sock->sk);
if (sock->sk->sk_state != TCP_LISTEN)
goto unlock_fail;
ssock = __mptcp_nmpc_socket(msk);
if (!ssock)
goto unlock_fail;
clear_bit(MPTCP_DATA_READY, &msk->flags);
sock_hold(ssock->sk);
release_sock(sock->sk);
err = ssock->ops->accept(sock, newsock, flags, kern);
if (err == 0 && !mptcp_is_tcpsk(newsock->sk)) {
struct mptcp_sock *msk = mptcp_sk(newsock->sk);
struct mptcp_subflow_context *subflow;
/* set ssk->sk_socket of accept()ed flows to mptcp socket.
* This is needed so NOSPACE flag can be set from tcp stack.
*/
__mptcp_flush_join_list(msk);
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
if (!ssk->sk_socket)
mptcp_sock_graft(ssk, newsock);
}
}
if (inet_csk_listen_poll(ssock->sk))
set_bit(MPTCP_DATA_READY, &msk->flags);
sock_put(ssock->sk);
return err;
unlock_fail:
release_sock(sock->sk);
return -EINVAL;
}
static __poll_t mptcp_check_readable(struct mptcp_sock *msk)
{
return test_bit(MPTCP_DATA_READY, &msk->flags) ? EPOLLIN | EPOLLRDNORM :
0;
}
static __poll_t mptcp_poll(struct file *file, struct socket *sock,
struct poll_table_struct *wait)
{
struct sock *sk = sock->sk;
struct mptcp_sock *msk;
__poll_t mask = 0;
int state;
msk = mptcp_sk(sk);
sock_poll_wait(file, sock, wait);
state = inet_sk_state_load(sk);
pr_debug("msk=%p state=%d flags=%lx", msk, state, msk->flags);
if (state == TCP_LISTEN)
return mptcp_check_readable(msk);
if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) {
mask |= mptcp_check_readable(msk);
if (test_bit(MPTCP_SEND_SPACE, &msk->flags))
mask |= EPOLLOUT | EPOLLWRNORM;
}
if (sk->sk_shutdown & RCV_SHUTDOWN)
mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
return mask;
}
static int mptcp_shutdown(struct socket *sock, int how)
{
struct mptcp_sock *msk = mptcp_sk(sock->sk);
struct sock *sk = sock->sk;
int ret = 0;
pr_debug("sk=%p, how=%d", msk, how);
lock_sock(sk);
how++;
if ((how & ~SHUTDOWN_MASK) || !how) {
ret = -EINVAL;
goto out_unlock;
}
if (sock->state == SS_CONNECTING) {
if ((1 << sk->sk_state) &
(TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE))
sock->state = SS_DISCONNECTING;
else
sock->state = SS_CONNECTED;
}
sk->sk_shutdown |= how;
if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk))
__mptcp_wr_shutdown(sk);
/* Wake up anyone sleeping in poll. */
sk->sk_state_change(sk);
out_unlock:
release_sock(sk);
return ret;
}
static const struct proto_ops mptcp_stream_ops = {
.family = PF_INET,
.owner = THIS_MODULE,
.release = inet_release,
.bind = mptcp_bind,
.connect = mptcp_stream_connect,
.socketpair = sock_no_socketpair,
.accept = mptcp_stream_accept,
.getname = inet_getname,
.poll = mptcp_poll,
.ioctl = inet_ioctl,
.gettstamp = sock_gettstamp,
.listen = mptcp_listen,
.shutdown = mptcp_shutdown,
.setsockopt = sock_common_setsockopt,
.getsockopt = sock_common_getsockopt,
.sendmsg = inet_sendmsg,
.recvmsg = inet_recvmsg,
.mmap = sock_no_mmap,
.sendpage = inet_sendpage,
};
static struct inet_protosw mptcp_protosw = {
.type = SOCK_STREAM,
.protocol = IPPROTO_MPTCP,
.prot = &mptcp_prot,
.ops = &mptcp_stream_ops,
.flags = INET_PROTOSW_ICSK,
};
void __init mptcp_proto_init(void)
{
mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo;
if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL))
panic("Failed to allocate MPTCP pcpu counter\n");
mptcp_subflow_init();
mptcp_pm_init();
mptcp_token_init();
if (proto_register(&mptcp_prot, 1) != 0)
panic("Failed to register MPTCP proto.\n");
inet_register_protosw(&mptcp_protosw);
BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb));
}
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
static const struct proto_ops mptcp_v6_stream_ops = {
.family = PF_INET6,
.owner = THIS_MODULE,
.release = inet6_release,
.bind = mptcp_bind,
.connect = mptcp_stream_connect,
.socketpair = sock_no_socketpair,
.accept = mptcp_stream_accept,
.getname = inet6_getname,
.poll = mptcp_poll,
.ioctl = inet6_ioctl,
.gettstamp = sock_gettstamp,
.listen = mptcp_listen,
.shutdown = mptcp_shutdown,
.setsockopt = sock_common_setsockopt,
.getsockopt = sock_common_getsockopt,
.sendmsg = inet6_sendmsg,
.recvmsg = inet6_recvmsg,
.mmap = sock_no_mmap,
.sendpage = inet_sendpage,
#ifdef CONFIG_COMPAT
.compat_ioctl = inet6_compat_ioctl,
#endif
};
static struct proto mptcp_v6_prot;
static void mptcp_v6_destroy(struct sock *sk)
{
mptcp_destroy(sk);
inet6_destroy_sock(sk);
}
static struct inet_protosw mptcp_v6_protosw = {
.type = SOCK_STREAM,
.protocol = IPPROTO_MPTCP,
.prot = &mptcp_v6_prot,
.ops = &mptcp_v6_stream_ops,
.flags = INET_PROTOSW_ICSK,
};
int __init mptcp_proto_v6_init(void)
{
int err;
mptcp_v6_prot = mptcp_prot;
strcpy(mptcp_v6_prot.name, "MPTCPv6");
mptcp_v6_prot.slab = NULL;
mptcp_v6_prot.destroy = mptcp_v6_destroy;
mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock);
err = proto_register(&mptcp_v6_prot, 1);
if (err)
return err;
err = inet6_register_protosw(&mptcp_v6_protosw);
if (err)
proto_unregister(&mptcp_v6_prot);
return err;
}
#endif
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