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mptcp: introduce MPTCP retransmission timer

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The timer will be used to schedule retransmission. It's
frequency is based on the current subflow RTO estimation and
is reset on every una_seq update

The timer is clearer for good by __mptcp_clear_xmit()

Also clean MPTCP rtx queue before each transmission.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paolo Abeni 2020-03-27 14:48:44 -07:00 committed by David S. Miller
parent 18b683bff8
commit b51f9b80c0
3 changed files with 93 additions and 2 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

4
net/mptcp/options.c
View file

@ -779,8 +779,10 @@ static void update_una(struct mptcp_sock *msk,
snd_una = old_snd_una;
old_snd_una = atomic64_cmpxchg(&msk->snd_una, snd_una,
new_snd_una);
if (old_snd_una == snd_una)
if (old_snd_una == snd_una) {
mptcp_data_acked((struct sock *)msk);
break;
}
}
}

89
net/mptcp/protocol.c
View file

@ -251,6 +251,46 @@ static void __mptcp_flush_join_list(struct mptcp_sock *msk)
spin_unlock_bh(&msk->join_list_lock);
}
static void mptcp_set_timeout(const struct sock *sk, const struct sock *ssk)
{
long tout = ssk && inet_csk(ssk)->icsk_pending ?
inet_csk(ssk)->icsk_timeout - jiffies : 0;
if (tout <= 0)
tout = mptcp_sk(sk)->timer_ival;
mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
}
static bool mptcp_timer_pending(struct sock *sk)
{
return timer_pending(&inet_csk(sk)->icsk_retransmit_timer);
}
static void mptcp_reset_timer(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
unsigned long tout;
/* should never be called with mptcp level timer cleared */
tout = READ_ONCE(mptcp_sk(sk)->timer_ival);
if (WARN_ON_ONCE(!tout))
tout = TCP_RTO_MIN;
sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout);
}
void mptcp_data_acked(struct sock *sk)
{
mptcp_reset_timer(sk);
}
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 bool mptcp_ext_cache_refill(struct mptcp_sock *msk)
{
if (!msk->cached_ext)
@ -596,10 +636,15 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
copied += ret;
}
mptcp_set_timeout(sk, ssk);
if (copied) {
ret = copied;
tcp_push(ssk, msg->msg_flags, mss_now, tcp_sk(ssk)->nonagle,
size_goal);
/* start the timer, if it's not pending */
if (!mptcp_timer_pending(sk))
mptcp_reset_timer(sk);
}
ssk_check_wmem(msk, ssk);
@ -787,6 +832,35 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
return copied;
}
static void mptcp_retransmit_handler(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
if (atomic64_read(&msk->snd_una) == msk->write_seq)
mptcp_stop_timer(sk);
else
mptcp_reset_timer(sk);
}
static void mptcp_retransmit_timer(struct timer_list *t)
{
struct inet_connection_sock *icsk = from_timer(icsk, t,
icsk_retransmit_timer);
struct sock *sk = &icsk->icsk_inet.sk;
bh_lock_sock(sk);
if (!sock_owned_by_user(sk)) {
mptcp_retransmit_handler(sk);
} else {
/* delegate our work to tcp_release_cb() */
if (!test_and_set_bit(TCP_WRITE_TIMER_DEFERRED,
&sk->sk_tsq_flags))
sock_hold(sk);
}
bh_unlock_sock(sk);
sock_put(sk);
}
/* subflow sockets can be either outgoing (connect) or incoming
* (accept).
*
@ -846,6 +920,9 @@ static int __mptcp_init_sock(struct sock *sk)
mptcp_pm_data_init(msk);
/* re-use the csk retrans timer for MPTCP-level retrans */
timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0);
return 0;
}
@ -867,6 +944,8 @@ static void __mptcp_clear_xmit(struct sock *sk)
struct mptcp_sock *msk = mptcp_sk(sk);
struct mptcp_data_frag *dtmp, *dfrag;
sk_stop_timer(sk, &msk->sk.icsk_retransmit_timer);
list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list)
dfrag_clear(dfrag);
}
@ -1155,7 +1234,8 @@ static int mptcp_getsockopt(struct sock *sk, int level, int optname,
return -EOPNOTSUPP;
}
#define MPTCP_DEFERRED_ALL TCPF_DELACK_TIMER_DEFERRED
#define MPTCP_DEFERRED_ALL (TCPF_DELACK_TIMER_DEFERRED | \
TCPF_WRITE_TIMER_DEFERRED)
/* this is very alike tcp_release_cb() but we must handle differently a
* different set of events
@ -1171,6 +1251,8 @@ static void mptcp_release_cb(struct sock *sk)
nflags = flags & ~MPTCP_DEFERRED_ALL;
} while (cmpxchg(&sk->sk_tsq_flags, flags, nflags) != flags);
sock_release_ownership(sk);
if (flags & TCPF_DELACK_TIMER_DEFERRED) {
struct mptcp_sock *msk = mptcp_sk(sk);
struct sock *ssk;
@ -1179,6 +1261,11 @@ static void mptcp_release_cb(struct sock *sk)
if (!ssk || !schedule_work(&msk->work))
__sock_put(sk);
}
if (flags & TCPF_WRITE_TIMER_DEFERRED) {
mptcp_retransmit_handler(sk);
__sock_put(sk);
}
}
static int mptcp_get_port(struct sock *sk, unsigned short snum)

2
net/mptcp/protocol.h
View file

@ -157,6 +157,7 @@ struct mptcp_sock {
u64 write_seq;
u64 ack_seq;
atomic64_t snd_una;
unsigned long timer_ival;
u32 token;
unsigned long flags;
bool can_ack;
@ -326,6 +327,7 @@ void mptcp_get_options(const struct sk_buff *skb,
void mptcp_finish_connect(struct sock *sk);
void mptcp_data_ready(struct sock *sk, struct sock *ssk);
bool mptcp_finish_join(struct sock *sk);
void mptcp_data_acked(struct sock *sk);
int mptcp_token_new_request(struct request_sock *req);
void mptcp_token_destroy_request(u32 token);