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Message-Id: <20200323212642.34104-9-mathew.j.martineau@linux.intel.com>
Date: Mon, 23 Mar 2020 14:26:33 -0700
From: Mat Martineau <mathew.j.martineau@...ux.intel.com>
To: netdev@...r.kernel.org
Cc: Paolo Abeni <pabeni@...hat.com>, eric.dumazet@...il.com,
Mat Martineau <mathew.j.martineau@...ux.intel.com>
Subject: [PATCH net-next 08/17] mptcp: introduce MPTCP retransmission timer
From: Paolo Abeni <pabeni@...hat.com>
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@...hat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@...ux.intel.com>
---
net/mptcp/options.c | 4 +-
net/mptcp/protocol.c | 89 +++++++++++++++++++++++++++++++++++++++++++-
net/mptcp/protocol.h | 2 +
3 files changed, 93 insertions(+), 2 deletions(-)
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index b0ff8ad702a3..bd220ee4aac9 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -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;
+ }
}
}
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index b06100509901..48eb054ae19e 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -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)
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index a1fdb879259a..d222eea11922 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -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);
--
2.26.0
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