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linux-zen-desktop/net/mptcp/protocol.c

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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 <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
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_charge(struct sock *sk, int size)
{
mptcp_sk(sk)->rmem_fwd_alloc -= 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_sk(sk)->rmem_fwd_alloc -= 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;
msk->rmem_fwd_alloc += 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);
}
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;
msk->rmem_fwd_alloc += 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_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 !__mptcp_check_fallback(msk) &&
((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;
if (__mptcp_check_fallback(msk))
return ret;
/* 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;
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;
}
/* 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);
return true;
}
static void __mptcp_flush_join_list(struct sock *sk)
{
struct mptcp_subflow_context *tmp, *subflow;
struct mptcp_sock *msk = mptcp_sk(sk);
list_for_each_entry_safe(subflow, tmp, &msk->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_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;
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;
msk_owned_by_me(msk);
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_timer_pending(sk) && !mptcp_data_fin_enabled(msk))
mptcp_stop_timer(sk);
} else {
mptcp_reset_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);
}
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 */
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_remove_empty_skb(ssk);
return 0;
}
zero_window_probe = true;
data_seq = snd_una - 1;
copy = 1;
/* all mptcp-level data is acked, no skbs should be present into the
* ssk write queue
*/
WARN_ON_ONCE(reuse_skb);
}
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;
WARN_ON_ONCE(zero_window_probe);
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;
msk_owned_by_me(msk);
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_timer_pending(sk))
mptcp_reset_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, bool first)
{
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;
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;
/* check for a different subflow usage only after
* spooling the first chunk of data
*/
xmit_ssk = first ? ssk : mptcp_subflow_get_send(msk);
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_timer_pending(sk))
mptcp_reset_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) {
mptcp_disconnect(sk, 0);
}
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;
/* silently ignore everything else */
msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | MSG_FASTOPEN;
lock_sock(sk);
ssock = __mptcp_nmpc_socket(msk);
if (unlikely(ssock && (inet_sk(ssock->sk)->defer_connect ||
msg->msg_flags & MSG_FASTOPEN))) {
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->sk_forward_alloc -= 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;
msk_owned_by_me(msk);
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_timeout_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;
msk_owned_by_me(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(msk))
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)
/* 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, mptcp either:
* - if either the subflow or the msk are dead, destroy the context
* (the subflow socket is deleted by inet_child_forget) and the msk
* - otherwise do nothing at the moment and take action at accept and/or
* listener shutdown - user-space must be able to accept() the closed
* socket.
*/
if (msk->in_accept_queue && msk->first == ssk) {
if (!sock_flag(sk, SOCK_DEAD) && !sock_flag(ssk, SOCK_DEAD))
return;
/* ensure later check in mptcp_worker() will dispose the msk */
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) {
/* be sure to force the tcp_disconnect() 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) {
tcp_disconnect(ssk, 0);
msk->subflow->state = SS_UNCONNECTED;
mptcp_subflow_ctx_reset(subflow);
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 */
if (ssk->sk_state == TCP_LISTEN) {
tcp_set_state(ssk, TCP_CLOSE);
mptcp_subflow_queue_clean(sk, ssk);
inet_csk_listen_stop(ssk);
mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CLOSED);
}
__tcp_close(ssk, 0);
/* close acquired an extra ref */
__sock_put(ssk);
}
out_release:
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);
}
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_should_close(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 || mptcp_sk(sk)->in_accept_queue)
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_check_fastclose(struct mptcp_sock *msk)
{
struct mptcp_subflow_context *subflow, *tmp;
struct sock *sk = (struct sock *)msk;
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:
sk->sk_err = ECONNREFUSED;
break;
case TCP_CLOSE_WAIT:
sk->sk_err = EPIPE;
break;
case TCP_CLOSE:
return;
default:
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_timer_pending(sk))
mptcp_reset_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_timeout(struct mptcp_sock *msk, unsigned long fail_tout)
{
struct sock *sk = (struct sock *)msk;
unsigned long timeout, close_timeout;
if (!fail_tout && !sock_flag(sk, SOCK_DEAD))
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 = sock_flag(sk, SOCK_DEAD) ? 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);
mptcp_reset_timeout(msk, 0);
}
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 = (struct sock *)msk;
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_data_fin_ack(sk);
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(sk);
if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
__mptcp_close_subflow(sk);
/* There is no point in keeping around an orphaned sk timedout or
* closed, but we need the msk around to reply to incoming DATA_FIN,
* even if it is orphaned and in FIN_WAIT2 state
*/
if (sock_flag(sk, SOCK_DEAD)) {
if (mptcp_should_close(sk)) {
inet_sk_state_store(sk, TCP_CLOSE);
mptcp_do_fastclose(sk);
}
if (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_timeout_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;
set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags);
/* 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(net->ipv4.sysctl_tcp_rmem[1]);
sk->sk_sndbuf = READ_ONCE(net->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:
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);
tcp_send_ack(ssk);
if (!mptcp_timer_pending(sk))
mptcp_reset_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);
/* fallback socket will not get data_fin/ack, can move to the next
* state now
*/
if (__mptcp_check_fallback(msk)) {
WRITE_ONCE(msk->snd_una, msk->write_seq);
if ((1 << sk->sk_state) & (TCPF_CLOSING | TCPF_LAST_ACK)) {
inet_sk_state_store(sk, TCP_CLOSE);
mptcp_close_wake_up(sk);
} else if (sk->sk_state == TCP_FIN_WAIT1) {
inet_sk_state_store(sk, TCP_FIN_WAIT2);
}
}
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_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);
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_listen_inuse_dec(struct sock *sk)
{
if (inet_sk_state_load(sk) == TCP_LISTEN)
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
}
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_listen_inuse_dec(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 */
inet_csk(sk)->icsk_mtup.probe_timestamp = tcp_jiffies32;
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 (msk->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_reset_timeout(msk, 0);
}
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). Do nothing and leave the cleanup to the
* caller.
*/
if (msk->fastopening)
return 0;
mptcp_listen_inuse_dec(sk);
inet_sk_state_store(sk, TCP_CLOSE);
mptcp_stop_timer(sk);
sk_stop_timer(sk, &sk->sk_timer);
if (msk->token)
mptcp_event(MPTCP_EVENT_CLOSED, msk, 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;
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;
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->sk_forward_alloc += msk->rmem_fwd_alloc;
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))
__mptcp_subflow_push_pending(sk, ssk, false);
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;
if (!flags)
break;
/* 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);
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)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
struct sock *sk = subflow->conn;
if (test_bit(MPTCP_DELEGATE_SEND, &subflow->delegated_status)) {
mptcp_data_lock(sk);
if (!sock_owned_by_user(sk))
__mptcp_subflow_push_pending(sk, ssk, true);
else
__set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags);
mptcp_data_unlock(sk);
mptcp_subflow_delegated_done(subflow, MPTCP_DELEGATE_SEND);
}
if (test_bit(MPTCP_DELEGATE_ACK, &subflow->delegated_status)) {
schedule_3rdack_retransmission(ssk);
mptcp_subflow_delegated_done(subflow, MPTCP_DELEGATE_ACK);
}
}
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;
subflow = mptcp_subflow_ctx(ssk);
sk = subflow->conn;
msk = mptcp_sk(sk);
pr_debug("msk=%p, token=%u", sk, subflow->token);
subflow->map_seq = subflow->iasn;
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->local_key, subflow->local_key);
WRITE_ONCE(msk->write_seq, subflow->idsn + 1);
WRITE_ONCE(msk->snd_nxt, msk->write_seq);
WRITE_ONCE(msk->snd_una, msk->write_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 sk->sk_forward_alloc + 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);
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) {
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
mptcp_copy_inaddrs(sk, ssock->sk);
}
mptcp_event_pm_listener(ssock->sk, MPTCP_EVENT_LISTENER_CREATED);
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;
set_bit(SOCK_CUSTOM_SOCKOPT, &newsock->flags);
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 (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_has_delegated_action(subflow))
mptcp_subflow_process_delegated(ssk);
/* ... elsewhere 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.
*/
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
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