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Date: Wed, 2 Oct 2019 16:36:47 -0700
From: Mat Martineau <mathew.j.martineau@...ux.intel.com>
To: netdev@...r.kernel.org, edumazet@...gle.com
Cc: Paolo Abeni <pabeni@...hat.com>, cpaasch@...le.com, fw@...len.de,
peter.krystad@...ux.intel.com, dcaratti@...hat.com,
matthieu.baerts@...sares.net
Subject: [RFC PATCH v2 37/45] 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>
---
net/mptcp/options.c | 4 +-
net/mptcp/protocol.c | 99 ++++++++++++++++++++++++++++++++++++++++++++
net/mptcp/protocol.h | 2 +
3 files changed, 104 insertions(+), 1 deletion(-)
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 2427fff98091..5e575999e281 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -568,8 +568,10 @@ void update_una(struct mptcp_sock *msk, struct mptcp_options_received *mp_opt)
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_reset_timer((struct sock *)msk);
break;
+ }
}
}
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index c2e89e8cbc0e..1f7a090ed25c 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -19,6 +19,41 @@
#include <net/mptcp.h>
#include "protocol.h"
+static void mptcp_set_timeout(const struct sock *sk, const struct sock *ssk)
+{
+ unsigned 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;
+}
+
+bool mptcp_timer_pending(struct sock *sk)
+{
+ return timer_pending(&inet_csk(sk)->icsk_retransmit_timer);
+}
+
+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);
+}
+
+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 struct socket *__mptcp_fallback_get_ref(const struct mptcp_sock *msk)
{
sock_owned_by_me((const struct sock *)msk);
@@ -308,10 +343,15 @@ 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);
}
release_sock(ssk);
@@ -680,6 +720,35 @@ 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);
+}
+
static int __mptcp_init_sock(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
@@ -687,6 +756,9 @@ static int __mptcp_init_sock(struct sock *sk)
INIT_LIST_HEAD(&msk->conn_list);
INIT_LIST_HEAD(&msk->rtx_queue);
+ /* re-use the csk retrans timer for MPTCP-level retrans */
+ timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0);
+
return 0;
}
@@ -708,6 +780,8 @@ 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);
}
@@ -884,6 +958,30 @@ static int mptcp_getsockopt(struct sock *sk, int level, int optname,
return -EOPNOTSUPP;
}
+#define MPTCP_DEFERRED_ALL TCPF_WRITE_TIMER_DEFERRED
+
+/* this is very alike tcp_release_cb() but we must handle differently a
+ * different set of events
+ */
+static void mptcp_release_cb(struct sock *sk)
+{
+ unsigned long flags, nflags;
+
+ do {
+ flags = sk->sk_tsq_flags;
+ if (!(flags & MPTCP_DEFERRED_ALL))
+ return;
+ nflags = flags & ~MPTCP_DEFERRED_ALL;
+ } while (cmpxchg(&sk->sk_tsq_flags, flags, nflags) != flags);
+
+ sock_release_ownership(sk);
+
+ if (flags & TCPF_WRITE_TIMER_DEFERRED) {
+ mptcp_retransmit_handler(sk);
+ __sock_put(sk);
+ }
+}
+
static int mptcp_get_port(struct sock *sk, unsigned short snum)
{
struct mptcp_sock *msk = mptcp_sk(sk);
@@ -986,6 +1084,7 @@ static struct proto mptcp_prot = {
.destroy = mptcp_destroy,
.sendmsg = mptcp_sendmsg,
.recvmsg = mptcp_recvmsg,
+ .release_cb = mptcp_release_cb,
.hash = inet_hash,
.unhash = inet_unhash,
.get_port = mptcp_get_port,
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index e09db0f85bfc..ef35d0aa8eb7 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -129,6 +129,7 @@ struct mptcp_sock {
u64 write_seq;
u64 ack_seq;
atomic64_t snd_una;
+ unsigned long timer_ival;
u32 token;
unsigned long flags;
u16 dport;
@@ -252,6 +253,7 @@ void mptcp_get_options(const struct sk_buff *skb,
void mptcp_finish_connect(struct sock *sk, int mp_capable);
void mptcp_finish_join(struct sock *sk);
+void mptcp_reset_timer(struct sock *sk);
int mptcp_token_new_request(struct request_sock *req);
void mptcp_token_destroy_request(u32 token);
--
2.23.0
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